-@c Copyright (C) 1988,1989,1992,1993,1994,1995,1996,1997,1998,1999,2000,2001,2002
+@c Copyright (C) 1988,1989,1992,1993,1994,1995,1996,1997,1998,1999,2000,2001,
+@c 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009
@c Free Software Foundation, Inc.
@c This is part of the GCC manual.
@c For copying conditions, see the file gcc.texi.
* Per-Function Data:: Defining data structures for per-function information.
* Storage Layout:: Defining sizes and alignments of data.
* Type Layout:: Defining sizes and properties of basic user data types.
-* Escape Sequences:: Defining the value of target character escape sequences
* Registers:: Naming and describing the hardware registers.
* Register Classes:: Defining the classes of hardware registers.
+* Old Constraints:: The old way to define machine-specific constraints.
* Stack and Calling:: Defining which way the stack grows and by how much.
-* Varargs:: Defining the varargs macros.
+* Varargs:: Defining the varargs macros.
* Trampolines:: Code set up at run time to enter a nested function.
* Library Calls:: Controlling how library routines are implicitly called.
* Addressing Modes:: Defining addressing modes valid for memory operands.
+* Anchored Addresses:: Defining how @option{-fsection-anchors} should work.
* Condition Code:: Defining how insns update the condition code.
* Costs:: Defining relative costs of different operations.
* Scheduling:: Adjusting the behavior of the instruction scheduler.
* Sections:: Dividing storage into text, data, and other sections.
-* PIC:: Macros for position independent code.
+* PIC:: Macros for position independent code.
* Assembler Format:: Defining how to write insns and pseudo-ops to output.
* Debugging Info:: Defining the format of debugging output.
-* Cross-compilation:: Handling floating point for cross-compilers.
+* Floating Point:: Handling floating point for cross-compilers.
* Mode Switching:: Insertion of mode-switching instructions.
* Target Attributes:: Defining target-specific uses of @code{__attribute__}.
+* Emulated TLS:: Emulated TLS support.
+* MIPS Coprocessors:: MIPS coprocessor support and how to customize it.
+* PCH Target:: Validity checking for precompiled headers.
+* C++ ABI:: Controlling C++ ABI changes.
* Misc:: Everything else.
@end menu
@c prevent bad page break with this line
You can control the compilation driver.
-@table @code
-@findex SWITCH_TAKES_ARG
-@item SWITCH_TAKES_ARG (@var{char})
+@defmac SWITCH_TAKES_ARG (@var{char})
A C expression which determines whether the option @option{-@var{char}}
takes arguments. The value should be the number of arguments that
option takes--zero, for many options.
wish to add additional options which take arguments. Any redefinition
should call @code{DEFAULT_SWITCH_TAKES_ARG} and then check for
additional options.
+@end defmac
-@findex WORD_SWITCH_TAKES_ARG
-@item WORD_SWITCH_TAKES_ARG (@var{name})
+@defmac WORD_SWITCH_TAKES_ARG (@var{name})
A C expression which determines whether the option @option{-@var{name}}
takes arguments. The value should be the number of arguments that
option takes--zero, for many options. This macro rather than
wish to add additional options which take arguments. Any redefinition
should call @code{DEFAULT_WORD_SWITCH_TAKES_ARG} and then check for
additional options.
+@end defmac
-@findex SWITCH_CURTAILS_COMPILATION
-@item SWITCH_CURTAILS_COMPILATION (@var{char})
+@defmac SWITCH_CURTAILS_COMPILATION (@var{char})
A C expression which determines whether the option @option{-@var{char}}
stops compilation before the generation of an executable. The value is
boolean, nonzero if the option does stop an executable from being
options which affect the generation of an executable. Any redefinition
should call @code{DEFAULT_SWITCH_CURTAILS_COMPILATION} and then check
for additional options.
+@end defmac
-@findex SWITCHES_NEED_SPACES
-@item SWITCHES_NEED_SPACES
+@defmac SWITCHES_NEED_SPACES
A string-valued C expression which enumerates the options for which
the linker needs a space between the option and its argument.
If this macro is not defined, the default value is @code{""}.
+@end defmac
-@findex TARGET_OPTION_TRANSLATE_TABLE
-@item TARGET_OPTION_TRANSLATE_TABLE
+@defmac TARGET_OPTION_TRANSLATE_TABLE
If defined, a list of pairs of strings, the first of which is a
potential command line target to the @file{gcc} driver program, and the
second of which is a space-separated (tabs and other whitespace are not
must be the @code{-opt} style. It is the intention of this macro to
provide a mechanism for substitution that affects the multilibs chosen,
such as one option that enables many options, some of which select
-multilibs. Example nonsensical definition, where @code{-malt-abi},
-@code{-EB}, and @code{-mspoo} cause different multilibs to be chosen:
+multilibs. Example nonsensical definition, where @option{-malt-abi},
+@option{-EB}, and @option{-mspoo} cause different multilibs to be chosen:
@smallexample
#define TARGET_OPTION_TRANSLATE_TABLE \
@{ "-fast", "-march=fast-foo -malt-abi -I/usr/fast-foo" @}, \
@{ "-compat", "-EB -malign=4 -mspoo" @}
@end smallexample
+@end defmac
-@findex CPP_SPEC
-@item CPP_SPEC
+@defmac DRIVER_SELF_SPECS
+A list of specs for the driver itself. It should be a suitable
+initializer for an array of strings, with no surrounding braces.
+
+The driver applies these specs to its own command line between loading
+default @file{specs} files (but not command-line specified ones) and
+choosing the multilib directory or running any subcommands. It
+applies them in the order given, so each spec can depend on the
+options added by earlier ones. It is also possible to remove options
+using @samp{%<@var{option}} in the usual way.
+
+This macro can be useful when a port has several interdependent target
+options. It provides a way of standardizing the command line so
+that the other specs are easier to write.
+
+Do not define this macro if it does not need to do anything.
+@end defmac
+
+@defmac OPTION_DEFAULT_SPECS
+A list of specs used to support configure-time default options (i.e.@:
+@option{--with} options) in the driver. It should be a suitable initializer
+for an array of structures, each containing two strings, without the
+outermost pair of surrounding braces.
+
+The first item in the pair is the name of the default. This must match
+the code in @file{config.gcc} for the target. The second item is a spec
+to apply if a default with this name was specified. The string
+@samp{%(VALUE)} in the spec will be replaced by the value of the default
+everywhere it occurs.
+
+The driver will apply these specs to its own command line between loading
+default @file{specs} files and processing @code{DRIVER_SELF_SPECS}, using
+the same mechanism as @code{DRIVER_SELF_SPECS}.
+
+Do not define this macro if it does not need to do anything.
+@end defmac
+
+@defmac CPP_SPEC
A C string constant that tells the GCC driver program options to
pass to CPP@. It can also specify how to translate options you
give to GCC into options for GCC to pass to the CPP@.
Do not define this macro if it does not need to do anything.
+@end defmac
-@findex CPLUSPLUS_CPP_SPEC
-@item CPLUSPLUS_CPP_SPEC
+@defmac CPLUSPLUS_CPP_SPEC
This macro is just like @code{CPP_SPEC}, but is used for C++, rather
than C@. If you do not define this macro, then the value of
@code{CPP_SPEC} (if any) will be used instead.
+@end defmac
-@findex NO_BUILTIN_SIZE_TYPE
-@item NO_BUILTIN_SIZE_TYPE
-If this macro is defined, the preprocessor will not define the built-in macro
-@code{__SIZE_TYPE__}. The macro @code{__SIZE_TYPE__} must then be defined
-by @code{CPP_SPEC} instead.
-
-This should be defined if @code{SIZE_TYPE} depends on target dependent flags
-which are not accessible to the preprocessor. Otherwise, it should not
-be defined.
-
-@findex NO_BUILTIN_PTRDIFF_TYPE
-@item NO_BUILTIN_PTRDIFF_TYPE
-If this macro is defined, the preprocessor will not define the built-in macro
-@code{__PTRDIFF_TYPE__}. The macro @code{__PTRDIFF_TYPE__} must then be
-defined by @code{CPP_SPEC} instead.
-
-This should be defined if @code{PTRDIFF_TYPE} depends on target dependent flags
-which are not accessible to the preprocessor. Otherwise, it should not
-be defined.
-
-@findex NO_BUILTIN_WCHAR_TYPE
-@item NO_BUILTIN_WCHAR_TYPE
-If this macro is defined, the preprocessor will not define the built-in macro
-@code{__WCHAR_TYPE__}. The macro @code{__WCHAR_TYPE__} must then be
-defined by @code{CPP_SPEC} instead.
-
-This should be defined if @code{WCHAR_TYPE} depends on target dependent flags
-which are not accessible to the preprocessor. Otherwise, it should not
-be defined.
-
-@findex NO_BUILTIN_WINT_TYPE
-@item NO_BUILTIN_WINT_TYPE
-If this macro is defined, the preprocessor will not define the built-in macro
-@code{__WINT_TYPE__}. The macro @code{__WINT_TYPE__} must then be
-defined by @code{CPP_SPEC} instead.
-
-This should be defined if @code{WINT_TYPE} depends on target dependent flags
-which are not accessible to the preprocessor. Otherwise, it should not
-be defined.
-
-@findex CC1_SPEC
-@item CC1_SPEC
+@defmac CC1_SPEC
A C string constant that tells the GCC driver program options to
pass to @code{cc1}, @code{cc1plus}, @code{f771}, and the other language
front ends.
for GCC to pass to front ends.
Do not define this macro if it does not need to do anything.
+@end defmac
-@findex CC1PLUS_SPEC
-@item CC1PLUS_SPEC
+@defmac CC1PLUS_SPEC
A C string constant that tells the GCC driver program options to
pass to @code{cc1plus}. It can also specify how to translate options you
give to GCC into options for GCC to pass to the @code{cc1plus}.
Note that everything defined in CC1_SPEC is already passed to
@code{cc1plus} so there is no need to duplicate the contents of
CC1_SPEC in CC1PLUS_SPEC@.
+@end defmac
-@findex ASM_SPEC
-@item ASM_SPEC
+@defmac ASM_SPEC
A C string constant that tells the GCC driver program options to
pass to the assembler. It can also specify how to translate options
you give to GCC into options for GCC to pass to the assembler.
See the file @file{sun3.h} for an example of this.
Do not define this macro if it does not need to do anything.
+@end defmac
-@findex ASM_FINAL_SPEC
-@item ASM_FINAL_SPEC
+@defmac ASM_FINAL_SPEC
A C string constant that tells the GCC driver program how to
run any programs which cleanup after the normal assembler.
Normally, this is not needed. See the file @file{mips.h} for
an example of this.
Do not define this macro if it does not need to do anything.
-
-@findex LINK_SPEC
-@item LINK_SPEC
+@end defmac
+
+@defmac AS_NEEDS_DASH_FOR_PIPED_INPUT
+Define this macro, with no value, if the driver should give the assembler
+an argument consisting of a single dash, @option{-}, to instruct it to
+read from its standard input (which will be a pipe connected to the
+output of the compiler proper). This argument is given after any
+@option{-o} option specifying the name of the output file.
+
+If you do not define this macro, the assembler is assumed to read its
+standard input if given no non-option arguments. If your assembler
+cannot read standard input at all, use a @samp{%@{pipe:%e@}} construct;
+see @file{mips.h} for instance.
+@end defmac
+
+@defmac LINK_SPEC
A C string constant that tells the GCC driver program options to
pass to the linker. It can also specify how to translate options you
give to GCC into options for GCC to pass to the linker.
Do not define this macro if it does not need to do anything.
+@end defmac
-@findex LIB_SPEC
-@item LIB_SPEC
+@defmac LIB_SPEC
Another C string constant used much like @code{LINK_SPEC}. The difference
between the two is that @code{LIB_SPEC} is used at the end of the
command given to the linker.
If this macro is not defined, a default is provided that
loads the standard C library from the usual place. See @file{gcc.c}.
+@end defmac
-@findex LIBGCC_SPEC
-@item LIBGCC_SPEC
+@defmac LIBGCC_SPEC
Another C string constant that tells the GCC driver program
how and when to place a reference to @file{libgcc.a} into the
linker command line. This constant is placed both before and after
If this macro is not defined, the GCC driver provides a default that
passes the string @option{-lgcc} to the linker.
-
-@findex STARTFILE_SPEC
-@item STARTFILE_SPEC
+@end defmac
+
+@defmac REAL_LIBGCC_SPEC
+By default, if @code{ENABLE_SHARED_LIBGCC} is defined, the
+@code{LIBGCC_SPEC} is not directly used by the driver program but is
+instead modified to refer to different versions of @file{libgcc.a}
+depending on the values of the command line flags @option{-static},
+@option{-shared}, @option{-static-libgcc}, and @option{-shared-libgcc}. On
+targets where these modifications are inappropriate, define
+@code{REAL_LIBGCC_SPEC} instead. @code{REAL_LIBGCC_SPEC} tells the
+driver how to place a reference to @file{libgcc} on the link command
+line, but, unlike @code{LIBGCC_SPEC}, it is used unmodified.
+@end defmac
+
+@defmac USE_LD_AS_NEEDED
+A macro that controls the modifications to @code{LIBGCC_SPEC}
+mentioned in @code{REAL_LIBGCC_SPEC}. If nonzero, a spec will be
+generated that uses --as-needed and the shared libgcc in place of the
+static exception handler library, when linking without any of
+@code{-static}, @code{-static-libgcc}, or @code{-shared-libgcc}.
+@end defmac
+
+@defmac LINK_EH_SPEC
+If defined, this C string constant is added to @code{LINK_SPEC}.
+When @code{USE_LD_AS_NEEDED} is zero or undefined, it also affects
+the modifications to @code{LIBGCC_SPEC} mentioned in
+@code{REAL_LIBGCC_SPEC}.
+@end defmac
+
+@defmac STARTFILE_SPEC
Another C string constant used much like @code{LINK_SPEC}. The
difference between the two is that @code{STARTFILE_SPEC} is used at
the very beginning of the command given to the linker.
If this macro is not defined, a default is provided that loads the
standard C startup file from the usual place. See @file{gcc.c}.
+@end defmac
-@findex ENDFILE_SPEC
-@item ENDFILE_SPEC
+@defmac ENDFILE_SPEC
Another C string constant used much like @code{LINK_SPEC}. The
difference between the two is that @code{ENDFILE_SPEC} is used at
the very end of the command given to the linker.
Do not define this macro if it does not need to do anything.
+@end defmac
-@findex THREAD_MODEL_SPEC
-@item THREAD_MODEL_SPEC
+@defmac THREAD_MODEL_SPEC
GCC @code{-v} will print the thread model GCC was configured to use.
However, this doesn't work on platforms that are multilibbed on thread
models, such as AIX 4.3. On such platforms, define
blanks that names one of the recognized thread models. @code{%*}, the
default value of this macro, will expand to the value of
@code{thread_file} set in @file{config.gcc}.
-
-@findex EXTRA_SPECS
-@item EXTRA_SPECS
+@end defmac
+
+@defmac SYSROOT_SUFFIX_SPEC
+Define this macro to add a suffix to the target sysroot when GCC is
+configured with a sysroot. This will cause GCC to search for usr/lib,
+et al, within sysroot+suffix.
+@end defmac
+
+@defmac SYSROOT_HEADERS_SUFFIX_SPEC
+Define this macro to add a headers_suffix to the target sysroot when
+GCC is configured with a sysroot. This will cause GCC to pass the
+updated sysroot+headers_suffix to CPP, causing it to search for
+usr/include, et al, within sysroot+headers_suffix.
+@end defmac
+
+@defmac EXTRA_SPECS
Define this macro to provide additional specifications to put in the
@file{specs} file that can be used in various specifications like
@code{CC1_SPEC}.
The @file{config/rs6000/rs6000.h} target file defines:
-@example
+@smallexample
#define EXTRA_SPECS \
@{ "cpp_sysv_default", CPP_SYSV_DEFAULT @},
#define CPP_SYS_DEFAULT ""
-@end example
+@end smallexample
The @file{config/rs6000/sysv.h} target file defines:
@smallexample
#undef CPP_SPEC
#define CPP_SPEC \
"%@{posix: -D_POSIX_SOURCE @} \
-%@{mcall-sysv: -D_CALL_SYSV @} %@{mcall-aix: -D_CALL_AIX @} \
-%@{!mcall-sysv: %@{!mcall-aix: %(cpp_sysv_default) @}@} \
+%@{mcall-sysv: -D_CALL_SYSV @} \
+%@{!mcall-sysv: %(cpp_sysv_default) @} \
%@{msoft-float: -D_SOFT_FLOAT@} %@{mcpu=403: -D_SOFT_FLOAT@}"
#undef CPP_SYSV_DEFAULT
#undef CPP_SYSV_DEFAULT
#define CPP_SYSV_DEFAULT "-D_CALL_AIX"
@end smallexample
+@end defmac
-@findex LINK_LIBGCC_SPECIAL
-@item LINK_LIBGCC_SPECIAL
-Define this macro if the driver program should find the library
-@file{libgcc.a} itself and should not pass @option{-L} options to the
-linker. If you do not define this macro, the driver program will pass
-the argument @option{-lgcc} to tell the linker to do the search and will
-pass @option{-L} options to it.
-
-@findex LINK_LIBGCC_SPECIAL_1
-@item LINK_LIBGCC_SPECIAL_1
+@defmac LINK_LIBGCC_SPECIAL_1
Define this macro if the driver program should find the library
@file{libgcc.a}. If you do not define this macro, the driver program will pass
the argument @option{-lgcc} to tell the linker to do the search.
-This macro is similar to @code{LINK_LIBGCC_SPECIAL}, except that it does
-not affect @option{-L} options.
+@end defmac
-@findex LINK_GCC_C_SEQUENCE_SPEC
-@item LINK_GCC_C_SEQUENCE_SPEC
+@defmac LINK_GCC_C_SEQUENCE_SPEC
The sequence in which libgcc and libc are specified to the linker.
By default this is @code{%G %L %G}.
+@end defmac
-@findex LINK_COMMAND_SPEC
-@item LINK_COMMAND_SPEC
+@defmac LINK_COMMAND_SPEC
A C string constant giving the complete command line need to execute the
linker. When you do this, you will need to update your port each time a
change is made to the link command line within @file{gcc.c}. Therefore,
line for invoking the linker and there is no other way to accomplish
the effect you need. Overriding this macro may be avoidable by overriding
@code{LINK_GCC_C_SEQUENCE_SPEC} instead.
+@end defmac
-@findex LINK_ELIMINATE_DUPLICATE_LDIRECTORIES
-@item LINK_ELIMINATE_DUPLICATE_LDIRECTORIES
+@defmac LINK_ELIMINATE_DUPLICATE_LDIRECTORIES
A nonzero value causes @command{collect2} to remove duplicate @option{-L@var{directory}} search
directories from linking commands. Do not give it a nonzero value if
removing duplicate search directories changes the linker's semantics.
+@end defmac
-@findex MULTILIB_DEFAULTS
-@item MULTILIB_DEFAULTS
+@defmac MULTILIB_DEFAULTS
Define this macro as a C expression for the initializer of an array of
string to tell the driver program which options are defaults for this
target and thus do not need to be handled specially when using
the target makefile fragment or if none of the options listed in
@code{MULTILIB_OPTIONS} are set by default.
@xref{Target Fragment}.
+@end defmac
-@findex RELATIVE_PREFIX_NOT_LINKDIR
-@item RELATIVE_PREFIX_NOT_LINKDIR
-Define this macro to tell @code{gcc} that it should only translate
+@defmac RELATIVE_PREFIX_NOT_LINKDIR
+Define this macro to tell @command{gcc} that it should only translate
a @option{-B} prefix into a @option{-L} linker option if the prefix
indicates an absolute file name.
+@end defmac
-@findex STANDARD_EXEC_PREFIX
-@item STANDARD_EXEC_PREFIX
-Define this macro as a C string constant if you wish to override the
-standard choice of @file{/usr/local/lib/gcc-lib/} as the default prefix to
-try when searching for the executable files of the compiler.
-
-@findex MD_EXEC_PREFIX
-@item MD_EXEC_PREFIX
+@defmac MD_EXEC_PREFIX
If defined, this macro is an additional prefix to try after
@code{STANDARD_EXEC_PREFIX}. @code{MD_EXEC_PREFIX} is not searched
when the @option{-b} option is used, or the compiler is built as a cross
compiler. If you define @code{MD_EXEC_PREFIX}, then be sure to add it
to the list of directories used to find the assembler in @file{configure.in}.
+@end defmac
-@findex STANDARD_STARTFILE_PREFIX
-@item STANDARD_STARTFILE_PREFIX
+@defmac STANDARD_STARTFILE_PREFIX
Define this macro as a C string constant if you wish to override the
-standard choice of @file{/usr/local/lib/} as the default prefix to
+standard choice of @code{libdir} as the default prefix to
try when searching for startup files such as @file{crt0.o}.
+@code{STANDARD_STARTFILE_PREFIX} is not searched when the compiler
+is built as a cross compiler.
+@end defmac
+
+@defmac STANDARD_STARTFILE_PREFIX_1
+Define this macro as a C string constant if you wish to override the
+standard choice of @code{/lib} as a prefix to try after the default prefix
+when searching for startup files such as @file{crt0.o}.
+@code{STANDARD_STARTFILE_PREFIX_1} is not searched when the compiler
+is built as a cross compiler.
+@end defmac
+
+@defmac STANDARD_STARTFILE_PREFIX_2
+Define this macro as a C string constant if you wish to override the
+standard choice of @code{/lib} as yet another prefix to try after the
+default prefix when searching for startup files such as @file{crt0.o}.
+@code{STANDARD_STARTFILE_PREFIX_2} is not searched when the compiler
+is built as a cross compiler.
+@end defmac
-@findex MD_STARTFILE_PREFIX
-@item MD_STARTFILE_PREFIX
+@defmac MD_STARTFILE_PREFIX
If defined, this macro supplies an additional prefix to try after the
standard prefixes. @code{MD_EXEC_PREFIX} is not searched when the
@option{-b} option is used, or when the compiler is built as a cross
compiler.
+@end defmac
-@findex MD_STARTFILE_PREFIX_1
-@item MD_STARTFILE_PREFIX_1
+@defmac MD_STARTFILE_PREFIX_1
If defined, this macro supplies yet another prefix to try after the
standard prefixes. It is not searched when the @option{-b} option is
used, or when the compiler is built as a cross compiler.
+@end defmac
-@findex INIT_ENVIRONMENT
-@item INIT_ENVIRONMENT
+@defmac INIT_ENVIRONMENT
Define this macro as a C string constant if you wish to set environment
variables for programs called by the driver, such as the assembler and
loader. The driver passes the value of this macro to @code{putenv} to
initialize the necessary environment variables.
+@end defmac
-@findex LOCAL_INCLUDE_DIR
-@item LOCAL_INCLUDE_DIR
+@defmac LOCAL_INCLUDE_DIR
Define this macro as a C string constant if you wish to override the
standard choice of @file{/usr/local/include} as the default prefix to
try when searching for local header files. @code{LOCAL_INCLUDE_DIR}
Cross compilers do not search either @file{/usr/local/include} or its
replacement.
+@end defmac
-@findex MODIFY_TARGET_NAME
-@item MODIFY_TARGET_NAME
-Define this macro if you with to define command-line switches that modify the
-default target name
+@defmac MODIFY_TARGET_NAME
+Define this macro if you wish to define command-line switches that
+modify the default target name.
For each switch, you can include a string to be appended to the first
part of the configuration name or a string to be deleted from the
@{ @{ "-32", DELETE, "64"@}, \
@{"-64", ADD, "64"@}@}
@end smallexample
+@end defmac
-
-@findex SYSTEM_INCLUDE_DIR
-@item SYSTEM_INCLUDE_DIR
+@defmac SYSTEM_INCLUDE_DIR
Define this macro as a C string constant if you wish to specify a
system-specific directory to search for header files before the standard
directory. @code{SYSTEM_INCLUDE_DIR} comes before
Cross compilers do not use this macro and do not search the directory
specified.
+@end defmac
-@findex STANDARD_INCLUDE_DIR
-@item STANDARD_INCLUDE_DIR
+@defmac STANDARD_INCLUDE_DIR
Define this macro as a C string constant if you wish to override the
standard choice of @file{/usr/include} as the default prefix to
try when searching for header files.
-Cross compilers do not use this macro and do not search either
+Cross compilers ignore this macro and do not search either
@file{/usr/include} or its replacement.
+@end defmac
-@findex STANDARD_INCLUDE_COMPONENT
-@item STANDARD_INCLUDE_COMPONENT
+@defmac STANDARD_INCLUDE_COMPONENT
The ``component'' corresponding to @code{STANDARD_INCLUDE_DIR}.
See @code{INCLUDE_DEFAULTS}, below, for the description of components.
If you do not define this macro, no component is used.
+@end defmac
-@findex INCLUDE_DEFAULTS
-@item INCLUDE_DEFAULTS
+@defmac INCLUDE_DEFAULTS
Define this macro if you wish to override the entire default search path
for include files. For a native compiler, the default search path
usually consists of @code{GCC_INCLUDE_DIR}, @code{LOCAL_INCLUDE_DIR},
the array with a null element.
The component name denotes what GNU package the include file is part of,
-if any, in all upper-case letters. For example, it might be @samp{GCC}
+if any, in all uppercase letters. For example, it might be @samp{GCC}
or @samp{BINUTILS}. If the package is part of a vendor-supplied
operating system, code the component name as @samp{0}.
For example, here is the definition used for VAX/VMS:
-@example
+@smallexample
#define INCLUDE_DEFAULTS \
@{ \
@{ "GNU_GXX_INCLUDE:", "G++", 1, 1@}, \
@{ ".", 0, 0, 0@}, \
@{ 0, 0, 0, 0@} \
@}
-@end example
-@end table
+@end smallexample
+@end defmac
Here is the order of prefixes tried for exec files:
Any prefixes specified by the user with @option{-B}.
@item
-The environment variable @code{GCC_EXEC_PREFIX}, if any.
+The environment variable @code{GCC_EXEC_PREFIX} or, if @code{GCC_EXEC_PREFIX}
+is not set and the compiler has not been installed in the configure-time
+@var{prefix}, the location in which the compiler has actually been installed.
@item
The directories specified by the environment variable @code{COMPILER_PATH}.
@item
-The macro @code{STANDARD_EXEC_PREFIX}.
+The macro @code{STANDARD_EXEC_PREFIX}, if the compiler has been installed
+in the configured-time @var{prefix}.
+
+@item
+The location @file{/usr/libexec/gcc/}, but only if this is a native compiler.
@item
-@file{/usr/lib/gcc/}.
+The location @file{/usr/lib/gcc/}, but only if this is a native compiler.
@item
-The macro @code{MD_EXEC_PREFIX}, if any.
+The macro @code{MD_EXEC_PREFIX}, if defined, but only if this is a native
+compiler.
@end enumerate
Here is the order of prefixes tried for startfiles:
Any prefixes specified by the user with @option{-B}.
@item
-The environment variable @code{GCC_EXEC_PREFIX}, if any.
+The environment variable @code{GCC_EXEC_PREFIX} or its automatically determined
+value based on the installed toolchain location.
@item
The directories specified by the environment variable @code{LIBRARY_PATH}
(or port-specific name; native only, cross compilers do not use this).
@item
-The macro @code{STANDARD_EXEC_PREFIX}.
+The macro @code{STANDARD_EXEC_PREFIX}, but only if the toolchain is installed
+in the configured @var{prefix} or this is a native compiler.
+
+@item
+The location @file{/usr/lib/gcc/}, but only if this is a native compiler.
@item
-@file{/usr/lib/gcc/}.
+The macro @code{MD_EXEC_PREFIX}, if defined, but only if this is a native
+compiler.
@item
-The macro @code{MD_EXEC_PREFIX}, if any.
+The macro @code{MD_STARTFILE_PREFIX}, if defined, but only if this is a
+native compiler, or we have a target system root.
@item
-The macro @code{MD_STARTFILE_PREFIX}, if any.
+The macro @code{MD_STARTFILE_PREFIX_1}, if defined, but only if this is a
+native compiler, or we have a target system root.
@item
-The macro @code{STANDARD_STARTFILE_PREFIX}.
+The macro @code{STANDARD_STARTFILE_PREFIX}, with any sysroot modifications.
+If this path is relative it will be prefixed by @code{GCC_EXEC_PREFIX} and
+the machine suffix or @code{STANDARD_EXEC_PREFIX} and the machine suffix.
@item
+The macro @code{STANDARD_STARTFILE_PREFIX_1}, but only if this is a native
+compiler, or we have a target system root. The default for this macro is
@file{/lib/}.
@item
+The macro @code{STANDARD_STARTFILE_PREFIX_2}, but only if this is a native
+compiler, or we have a target system root. The default for this macro is
@file{/usr/lib/}.
@end enumerate
@c prevent bad page break with this line
Here are run-time target specifications.
-@table @code
-@findex CPP_PREDEFINES
-@item CPP_PREDEFINES
-Define this to be a string constant containing @option{-D} options to
-define the predefined macros that identify this machine and system.
-These macros will be predefined unless the @option{-ansi} option (or a
-@option{-std} option for strict ISO C conformance) is specified.
-
-In addition, a parallel set of macros are predefined, whose names are
-made by appending @samp{__} at the beginning and at the end. These
-@samp{__} macros are permitted by the ISO standard, so they are
-predefined regardless of whether @option{-ansi} or a @option{-std} option
-is specified.
-
-For example, on the Sun, one can use the following value:
-
-@smallexample
-"-Dmc68000 -Dsun -Dunix"
-@end smallexample
-
-The result is to define the macros @code{__mc68000__}, @code{__sun__}
-and @code{__unix__} unconditionally, and the macros @code{mc68000},
-@code{sun} and @code{unix} provided @option{-ansi} is not specified.
+@defmac TARGET_CPU_CPP_BUILTINS ()
+This function-like macro expands to a block of code that defines
+built-in preprocessor macros and assertions for the target CPU, using
+the functions @code{builtin_define}, @code{builtin_define_std} and
+@code{builtin_assert}. When the front end
+calls this macro it provides a trailing semicolon, and since it has
+finished command line option processing your code can use those
+results freely.
+
+@code{builtin_assert} takes a string in the form you pass to the
+command-line option @option{-A}, such as @code{cpu=mips}, and creates
+the assertion. @code{builtin_define} takes a string in the form
+accepted by option @option{-D} and unconditionally defines the macro.
+
+@code{builtin_define_std} takes a string representing the name of an
+object-like macro. If it doesn't lie in the user's namespace,
+@code{builtin_define_std} defines it unconditionally. Otherwise, it
+defines a version with two leading underscores, and another version
+with two leading and trailing underscores, and defines the original
+only if an ISO standard was not requested on the command line. For
+example, passing @code{unix} defines @code{__unix}, @code{__unix__}
+and possibly @code{unix}; passing @code{_mips} defines @code{__mips},
+@code{__mips__} and possibly @code{_mips}, and passing @code{_ABI64}
+defines only @code{_ABI64}.
+
+You can also test for the C dialect being compiled. The variable
+@code{c_language} is set to one of @code{clk_c}, @code{clk_cplusplus}
+or @code{clk_objective_c}. Note that if we are preprocessing
+assembler, this variable will be @code{clk_c} but the function-like
+macro @code{preprocessing_asm_p()} will return true, so you might want
+to check for that first. If you need to check for strict ANSI, the
+variable @code{flag_iso} can be used. The function-like macro
+@code{preprocessing_trad_p()} can be used to check for traditional
+preprocessing.
+@end defmac
+
+@defmac TARGET_OS_CPP_BUILTINS ()
+Similarly to @code{TARGET_CPU_CPP_BUILTINS} but this macro is optional
+and is used for the target operating system instead.
+@end defmac
+
+@defmac TARGET_OBJFMT_CPP_BUILTINS ()
+Similarly to @code{TARGET_CPU_CPP_BUILTINS} but this macro is optional
+and is used for the target object format. @file{elfos.h} uses this
+macro to define @code{__ELF__}, so you probably do not need to define
+it yourself.
+@end defmac
+
+@deftypevar {extern int} target_flags
+This variable is declared in @file{options.h}, which is included before
+any target-specific headers.
+@end deftypevar
-@findex extern int target_flags
-@item extern int target_flags;
-This declaration should be present.
+@deftypevar {Target Hook} int TARGET_DEFAULT_TARGET_FLAGS
+This variable specifies the initial value of @code{target_flags}.
+Its default setting is 0.
+@end deftypevar
@cindex optional hardware or system features
@cindex features, optional, in system conventions
-@item TARGET_@dots{}
-This series of macros is to allow compiler command arguments to
-enable or disable the use of optional features of the target machine.
-For example, one machine description serves both the 68000 and
-the 68020; a command argument tells the compiler whether it should
-use 68020-only instructions or not. This command argument works
-by means of a macro @code{TARGET_68020} that tests a bit in
-@code{target_flags}.
-
-Define a macro @code{TARGET_@var{featurename}} for each such option.
-Its definition should test a bit in @code{target_flags}. It is
-recommended that a helper macro @code{TARGET_MASK_@var{featurename}}
-is defined for each bit-value to test, and used in
-@code{TARGET_@var{featurename}} and @code{TARGET_SWITCHES}. For
-example:
-
-@smallexample
-#define TARGET_MASK_68020 1
-#define TARGET_68020 (target_flags & TARGET_MASK_68020)
-@end smallexample
-
-One place where these macros are used is in the condition-expressions
-of instruction patterns. Note how @code{TARGET_68020} appears
-frequently in the 68000 machine description file, @file{m68k.md}.
-Another place they are used is in the definitions of the other
-macros in the @file{@var{machine}.h} file.
-
-@findex TARGET_SWITCHES
-@item TARGET_SWITCHES
-This macro defines names of command options to set and clear
-bits in @code{target_flags}. Its definition is an initializer
-with a subgrouping for each command option.
-
-Each subgrouping contains a string constant, that defines the option
-name, a number, which contains the bits to set in
-@code{target_flags}, and a second string which is the description
-displayed by @option{--help}. If the number is negative then the bits specified
-by the number are cleared instead of being set. If the description
-string is present but empty, then no help information will be displayed
-for that option, but it will not count as an undocumented option. The
-actual option name is made by appending @samp{-m} to the specified name.
-Non-empty description strings should be marked with @code{N_(@dots{})} for
-@command{xgettext}. Please do not mark empty strings because the empty
-string is reserved by GNU gettext. @code{gettext("")} returns the header entry
-of the message catalog with meta information, not the empty string.
-
-In addition to the description for @option{--help},
-more detailed documentation for each option should be added to
-@file{invoke.texi}.
-
-One of the subgroupings should have a null string. The number in
-this grouping is the default value for @code{target_flags}. Any
-target options act starting with that value.
-
-Here is an example which defines @option{-m68000} and @option{-m68020}
-with opposite meanings, and picks the latter as the default:
-
-@smallexample
-#define TARGET_SWITCHES \
- @{ @{ "68020", TARGET_MASK_68020, "" @}, \
- @{ "68000", -TARGET_MASK_68020, \
- N_("Compile for the 68000") @}, \
- @{ "", TARGET_MASK_68020, "" @}@}
-@end smallexample
-@findex TARGET_OPTIONS
-@item TARGET_OPTIONS
-This macro is similar to @code{TARGET_SWITCHES} but defines names of command
-options that have values. Its definition is an initializer with a
-subgrouping for each command option.
-
-Each subgrouping contains a string constant, that defines the fixed part
-of the option name, the address of a variable, and a description string.
-Non-empty description strings should be marked with @code{N_(@dots{})} for
-@command{xgettext}. Please do not mark empty strings because the empty
-string is reserved by GNU gettext. @code{gettext("")} returns the header entry
-of the message catalog with meta information, not the empty string.
-
-The variable, type @code{char *}, is set to the variable part of the
-given option if the fixed part matches. The actual option name is made
-by appending @samp{-m} to the specified name. Again, each option should
-also be documented in @file{invoke.texi}.
-
-Here is an example which defines @option{-mshort-data-@var{number}}. If the
-given option is @option{-mshort-data-512}, the variable @code{m88k_short_data}
-will be set to the string @code{"512"}.
+@deftypefn {Target Hook} bool TARGET_HANDLE_OPTION (size_t @var{code}, const char *@var{arg}, int @var{value})
+This hook is called whenever the user specifies one of the
+target-specific options described by the @file{.opt} definition files
+(@pxref{Options}). It has the opportunity to do some option-specific
+processing and should return true if the option is valid. The default
+definition does nothing but return true.
+
+@var{code} specifies the @code{OPT_@var{name}} enumeration value
+associated with the selected option; @var{name} is just a rendering of
+the option name in which non-alphanumeric characters are replaced by
+underscores. @var{arg} specifies the string argument and is null if
+no argument was given. If the option is flagged as a @code{UInteger}
+(@pxref{Option properties}), @var{value} is the numeric value of the
+argument. Otherwise @var{value} is 1 if the positive form of the
+option was used and 0 if the ``no-'' form was.
+@end deftypefn
-@smallexample
-extern char *m88k_short_data;
-#define TARGET_OPTIONS \
- @{ @{ "short-data-", &m88k_short_data, \
- N_("Specify the size of the short data section") @} @}
-@end smallexample
+@deftypefn {Target Hook} bool TARGET_HANDLE_C_OPTION (size_t @var{code}, const char *@var{arg}, int @var{value})
+This target hook is called whenever the user specifies one of the
+target-specific C language family options described by the @file{.opt}
+definition files(@pxref{Options}). It has the opportunity to do some
+option-specific processing and should return true if the option is
+valid. The default definition does nothing but return false.
+
+In general, you should use @code{TARGET_HANDLE_OPTION} to handle
+options. However, if processing an option requires routines that are
+only available in the C (and related language) front ends, then you
+should use @code{TARGET_HANDLE_C_OPTION} instead.
+@end deftypefn
-@findex TARGET_VERSION
-@item TARGET_VERSION
+@defmac TARGET_VERSION
This macro is a C statement to print on @code{stderr} a string
describing the particular machine description choice. Every machine
description should define @code{TARGET_VERSION}. For example:
fprintf (stderr, " (68k, MIT syntax)");
#endif
@end smallexample
+@end defmac
-@findex OVERRIDE_OPTIONS
-@item OVERRIDE_OPTIONS
+@defmac OVERRIDE_OPTIONS
Sometimes certain combinations of command options do not make sense on
a particular target machine. You can define a macro
@code{OVERRIDE_OPTIONS} to take account of this. This macro, if
Don't use this macro to turn on various extra optimizations for
@option{-O}. That is what @code{OPTIMIZATION_OPTIONS} is for.
+@end defmac
+
+@defmac C_COMMON_OVERRIDE_OPTIONS
+This is similar to @code{OVERRIDE_OPTIONS} but is only used in the C
+language frontends (C, Objective-C, C++, Objective-C++) and so can be
+used to alter option flag variables which only exist in those
+frontends.
+@end defmac
-@findex OPTIMIZATION_OPTIONS
-@item OPTIMIZATION_OPTIONS (@var{level}, @var{size})
+@defmac OPTIMIZATION_OPTIONS (@var{level}, @var{size})
Some machines may desire to change what optimizations are performed for
various optimization levels. This macro, if defined, is executed once
just after the optimization level is determined and before the remainder
@var{size} is nonzero if @option{-Os} is specified and zero otherwise.
-You should not use this macro to change options that are not
-machine-specific. These should uniformly selected by the same
-optimization level on all supported machines. Use this macro to enable
-machine-specific optimizations.
+This macro is run once at program startup and when the optimization
+options are changed via @code{#pragma GCC optimize} or by using the
+@code{optimize} attribute.
@strong{Do not examine @code{write_symbols} in
this macro!} The debugging options are not supposed to alter the
generated code.
+@end defmac
-@findex CAN_DEBUG_WITHOUT_FP
-@item CAN_DEBUG_WITHOUT_FP
+@deftypefn {Target Hook} bool TARGET_HELP (void)
+This hook is called in response to the user invoking
+@option{--target-help} on the command line. It gives the target a
+chance to display extra information on the target specific command
+line options found in its @file{.opt} file.
+@end deftypefn
+
+@defmac CAN_DEBUG_WITHOUT_FP
Define this macro if debugging can be performed even without a frame
pointer. If this macro is defined, GCC will turn on the
@option{-fomit-frame-pointer} option whenever @option{-O} is specified.
-@end table
+@end defmac
@node Per-Function Data
@section Defining data structures for per-function information.
to their own specific data.
If a target needs per-function specific data it should define the type
-@code{struct machine_function} and also the macro
-@code{INIT_EXPANDERS}. This macro should be used to initialize some or
-all of the function pointers @code{init_machine_status},
-@code{free_machine_status} and @code{mark_machine_status}. These
-pointers are explained below.
+@code{struct machine_function} and also the macro @code{INIT_EXPANDERS}.
+This macro should be used to initialize the function pointer
+@code{init_machine_status}. This pointer is explained below.
One typical use of per-function, target specific data is to create an
RTX to hold the register containing the function's return address. This
single data area approach is no longer used, these pointers are no
longer supported.
-The macro and function pointers are described below.
-
-@table @code
-@findex INIT_EXPANDERS
-@item INIT_EXPANDERS
+@defmac INIT_EXPANDERS
Macro called to initialize any target specific information. This macro
is called once per function, before generation of any RTL has begun.
The intention of this macro is to allow the initialization of the
-function pointers below.
-
-@findex init_machine_status
-@item init_machine_status
-This is a @code{void (*)(struct function *)} function pointer. If this
-pointer is non-@code{NULL} it will be called once per function, before function
-compilation starts, in order to allow the target to perform any target
-specific initialization of the @code{struct function} structure. It is
-intended that this would be used to initialize the @code{machine} of
-that structure.
-
-@findex free_machine_status
-@item free_machine_status
-This is a @code{void (*)(struct function *)} function pointer. If this
-pointer is non-@code{NULL} it will be called once per function, after the
-function has been compiled, in order to allow any memory allocated
-during the @code{init_machine_status} function call to be freed.
-
-@findex mark_machine_status
-@item mark_machine_status
-This is a @code{void (*)(struct function *)} function pointer. If this
-pointer is non-@code{NULL} it will be called once per function in order to mark
-any data items in the @code{struct machine_function} structure which
-need garbage collection.
-
-@end table
+function pointer @code{init_machine_status}.
+@end defmac
+
+@deftypevar {void (*)(struct function *)} init_machine_status
+If this function pointer is non-@code{NULL} it will be called once per
+function, before function compilation starts, in order to allow the
+target to perform any target specific initialization of the
+@code{struct function} structure. It is intended that this would be
+used to initialize the @code{machine} of that structure.
+
+@code{struct machine_function} structures are expected to be freed by GC@.
+Generally, any memory that they reference must be allocated by using
+@code{ggc_alloc}, including the structure itself.
+@end deftypevar
@node Storage Layout
@section Storage Layout
expressions that refer to static variables, such as the @code{target_flags}.
@xref{Run-time Target}.
-@table @code
-@findex BITS_BIG_ENDIAN
-@item BITS_BIG_ENDIAN
+@defmac BITS_BIG_ENDIAN
Define this macro to have the value 1 if the most significant bit in a
byte has the lowest number; otherwise define it to have the value zero.
This means that bit-field instructions count from the most significant
This macro does not affect the way structure fields are packed into
bytes or words; that is controlled by @code{BYTES_BIG_ENDIAN}.
+@end defmac
-@findex BYTES_BIG_ENDIAN
-@item BYTES_BIG_ENDIAN
+@defmac BYTES_BIG_ENDIAN
Define this macro to have the value 1 if the most significant byte in a
word has the lowest number. This macro need not be a constant.
+@end defmac
-@findex WORDS_BIG_ENDIAN
-@item WORDS_BIG_ENDIAN
+@defmac WORDS_BIG_ENDIAN
Define this macro to have the value 1 if, in a multiword object, the
most significant word has the lowest number. This applies to both
memory locations and registers; GCC fundamentally assumes that the
order of words in memory is the same as the order in registers. This
macro need not be a constant.
+@end defmac
-@findex LIBGCC2_WORDS_BIG_ENDIAN
-@item LIBGCC2_WORDS_BIG_ENDIAN
+@defmac LIBGCC2_WORDS_BIG_ENDIAN
Define this macro if @code{WORDS_BIG_ENDIAN} is not constant. This must be a
constant value with the same meaning as @code{WORDS_BIG_ENDIAN}, which will be
used only when compiling @file{libgcc2.c}. Typically the value will be set
based on preprocessor defines.
+@end defmac
-@findex FLOAT_WORDS_BIG_ENDIAN
-@item FLOAT_WORDS_BIG_ENDIAN
+@defmac FLOAT_WORDS_BIG_ENDIAN
Define this macro to have the value 1 if @code{DFmode}, @code{XFmode} or
@code{TFmode} floating point numbers are stored in memory with the word
containing the sign bit at the lowest address; otherwise define it to
You need not define this macro if the ordering is the same as for
multi-word integers.
+@end defmac
-@findex BITS_PER_UNIT
-@item BITS_PER_UNIT
+@defmac BITS_PER_UNIT
Define this macro to be the number of bits in an addressable storage
-unit (byte); normally 8.
+unit (byte). If you do not define this macro the default is 8.
+@end defmac
-@findex BITS_PER_WORD
-@item BITS_PER_WORD
-Number of bits in a word; normally 32.
+@defmac BITS_PER_WORD
+Number of bits in a word. If you do not define this macro, the default
+is @code{BITS_PER_UNIT * UNITS_PER_WORD}.
+@end defmac
-@findex MAX_BITS_PER_WORD
-@item MAX_BITS_PER_WORD
+@defmac MAX_BITS_PER_WORD
Maximum number of bits in a word. If this is undefined, the default is
@code{BITS_PER_WORD}. Otherwise, it is the constant value that is the
largest value that @code{BITS_PER_WORD} can have at run-time.
+@end defmac
-@findex UNITS_PER_WORD
-@item UNITS_PER_WORD
-Number of storage units in a word; normally 4.
+@defmac UNITS_PER_WORD
+Number of storage units in a word; normally the size of a general-purpose
+register, a power of two from 1 or 8.
+@end defmac
-@findex MIN_UNITS_PER_WORD
-@item MIN_UNITS_PER_WORD
+@defmac MIN_UNITS_PER_WORD
Minimum number of units in a word. If this is undefined, the default is
@code{UNITS_PER_WORD}. Otherwise, it is the constant value that is the
smallest value that @code{UNITS_PER_WORD} can have at run-time.
+@end defmac
+
+@defmac UNITS_PER_SIMD_WORD (@var{mode})
+Number of units in the vectors that the vectorizer can produce for
+scalar mode @var{mode}. The default is equal to @code{UNITS_PER_WORD},
+because the vectorizer can do some transformations even in absence of
+specialized @acronym{SIMD} hardware.
+@end defmac
-@findex POINTER_SIZE
-@item POINTER_SIZE
+@defmac POINTER_SIZE
Width of a pointer, in bits. You must specify a value no wider than the
width of @code{Pmode}. If it is not equal to the width of @code{Pmode},
-you must define @code{POINTERS_EXTEND_UNSIGNED}.
-
-@findex POINTERS_EXTEND_UNSIGNED
-@item POINTERS_EXTEND_UNSIGNED
-A C expression whose value is greater than zero if pointers that need to be
-extended from being @code{POINTER_SIZE} bits wide to @code{Pmode} are to
-be zero-extended and zero if they are to be sign-extended. If the value
-is less then zero then there must be an "ptr_extend" instruction that
-extends a pointer from @code{POINTER_SIZE} to @code{Pmode}.
-
-You need not define this macro if the @code{POINTER_SIZE} is equal
-to the width of @code{Pmode}.
-
-@findex PROMOTE_MODE
-@item PROMOTE_MODE (@var{m}, @var{unsignedp}, @var{type})
+you must define @code{POINTERS_EXTEND_UNSIGNED}. If you do not specify
+a value the default is @code{BITS_PER_WORD}.
+@end defmac
+
+@defmac POINTERS_EXTEND_UNSIGNED
+A C expression that determines how pointers should be extended from
+@code{ptr_mode} to either @code{Pmode} or @code{word_mode}. It is
+greater than zero if pointers should be zero-extended, zero if they
+should be sign-extended, and negative if some other sort of conversion
+is needed. In the last case, the extension is done by the target's
+@code{ptr_extend} instruction.
+
+You need not define this macro if the @code{ptr_mode}, @code{Pmode}
+and @code{word_mode} are all the same width.
+@end defmac
+
+@defmac PROMOTE_MODE (@var{m}, @var{unsignedp}, @var{type})
A macro to update @var{m} and @var{unsignedp} when an object whose type
is @var{type} and which has the specified mode and signedness is to be
stored in a register. This macro is only called when @var{type} is a
@var{unsignedp} according to which kind of extension is more efficient.
Do not define this macro if it would never modify @var{m}.
+@end defmac
+
+@defmac PROMOTE_FUNCTION_MODE
+Like @code{PROMOTE_MODE}, but is applied to outgoing function arguments or
+function return values, as specified by @code{TARGET_PROMOTE_FUNCTION_ARGS}
+and @code{TARGET_PROMOTE_FUNCTION_RETURN}, respectively.
-@findex PROMOTE_FUNCTION_ARGS
-@item PROMOTE_FUNCTION_ARGS
-Define this macro if the promotion described by @code{PROMOTE_MODE}
-should also be done for outgoing function arguments.
+The default is @code{PROMOTE_MODE}.
+@end defmac
-@findex PROMOTE_FUNCTION_RETURN
-@item PROMOTE_FUNCTION_RETURN
-Define this macro if the promotion described by @code{PROMOTE_MODE}
-should also be done for the return value of functions.
+@deftypefn {Target Hook} bool TARGET_PROMOTE_FUNCTION_ARGS (tree @var{fntype})
+This target hook should return @code{true} if the promotion described by
+@code{PROMOTE_FUNCTION_MODE} should be done for outgoing function
+arguments.
+@end deftypefn
-If this macro is defined, @code{FUNCTION_VALUE} must perform the same
-promotions done by @code{PROMOTE_MODE}.
+@deftypefn {Target Hook} bool TARGET_PROMOTE_FUNCTION_RETURN (tree @var{fntype})
+This target hook should return @code{true} if the promotion described by
+@code{PROMOTE_FUNCTION_MODE} should be done for the return value of
+functions.
-@findex PROMOTE_FOR_CALL_ONLY
-@item PROMOTE_FOR_CALL_ONLY
-Define this macro if the promotion described by @code{PROMOTE_MODE}
-should @emph{only} be performed for outgoing function arguments or
-function return values, as specified by @code{PROMOTE_FUNCTION_ARGS}
-and @code{PROMOTE_FUNCTION_RETURN}, respectively.
+If this target hook returns @code{true}, @code{TARGET_FUNCTION_VALUE}
+must perform the same promotions done by @code{PROMOTE_FUNCTION_MODE}.
+@end deftypefn
-@findex PARM_BOUNDARY
-@item PARM_BOUNDARY
+@defmac PARM_BOUNDARY
Normal alignment required for function parameters on the stack, in
bits. All stack parameters receive at least this much alignment
regardless of data type. On most machines, this is the same as the
size of an integer.
+@end defmac
-@findex STACK_BOUNDARY
-@item STACK_BOUNDARY
+@defmac STACK_BOUNDARY
Define this macro to the minimum alignment enforced by hardware for the
stack pointer on this machine. The definition is a C expression for the
desired alignment (measured in bits). This value is used as a default
if @code{PREFERRED_STACK_BOUNDARY} is not defined. On most machines,
this should be the same as @code{PARM_BOUNDARY}.
+@end defmac
-@findex PREFERRED_STACK_BOUNDARY
-@item PREFERRED_STACK_BOUNDARY
+@defmac PREFERRED_STACK_BOUNDARY
Define this macro if you wish to preserve a certain alignment for the
stack pointer, greater than what the hardware enforces. The definition
is a C expression for the desired alignment (measured in bits). This
macro must evaluate to a value equal to or larger than
@code{STACK_BOUNDARY}.
+@end defmac
-@findex FORCE_PREFERRED_STACK_BOUNDARY_IN_MAIN
-@item FORCE_PREFERRED_STACK_BOUNDARY_IN_MAIN
-A C expression that evaluates true if @code{PREFERRED_STACK_BOUNDARY} is
-not guaranteed by the runtime and we should emit code to align the stack
-at the beginning of @code{main}.
+@defmac INCOMING_STACK_BOUNDARY
+Define this macro if the incoming stack boundary may be different
+from @code{PREFERRED_STACK_BOUNDARY}. This macro must evaluate
+to a value equal to or larger than @code{STACK_BOUNDARY}.
+@end defmac
-@cindex @code{PUSH_ROUNDING}, interaction with @code{PREFERRED_STACK_BOUNDARY}
-If @code{PUSH_ROUNDING} is not defined, the stack will always be aligned
-to the specified boundary. If @code{PUSH_ROUNDING} is defined and specifies
-a less strict alignment than @code{PREFERRED_STACK_BOUNDARY}, the stack may
-be momentarily unaligned while pushing arguments.
-
-@findex FUNCTION_BOUNDARY
-@item FUNCTION_BOUNDARY
+@defmac FUNCTION_BOUNDARY
Alignment required for a function entry point, in bits.
+@end defmac
+
+@defmac BIGGEST_ALIGNMENT
+Biggest alignment that any data type can require on this machine, in
+bits. Note that this is not the biggest alignment that is supported,
+just the biggest alignment that, when violated, may cause a fault.
+@end defmac
-@findex BIGGEST_ALIGNMENT
-@item BIGGEST_ALIGNMENT
-Biggest alignment that any data type can require on this machine, in bits.
+@defmac MALLOC_ABI_ALIGNMENT
+Alignment, in bits, a C conformant malloc implementation has to
+provide. If not defined, the default value is @code{BITS_PER_WORD}.
+@end defmac
-@findex MINIMUM_ATOMIC_ALIGNMENT
-@item MINIMUM_ATOMIC_ALIGNMENT
+@defmac ATTRIBUTE_ALIGNED_VALUE
+Alignment used by the @code{__attribute__ ((aligned))} construct. If
+not defined, the default value is @code{BIGGEST_ALIGNMENT}.
+@end defmac
+
+@defmac MINIMUM_ATOMIC_ALIGNMENT
If defined, the smallest alignment, in bits, that can be given to an
object that can be referenced in one operation, without disturbing any
nearby object. Normally, this is @code{BITS_PER_UNIT}, but may be larger
on machines that don't have byte or half-word store operations.
+@end defmac
-@findex BIGGEST_FIELD_ALIGNMENT
-@item BIGGEST_FIELD_ALIGNMENT
+@defmac BIGGEST_FIELD_ALIGNMENT
Biggest alignment that any structure or union field can require on this
machine, in bits. If defined, this overrides @code{BIGGEST_ALIGNMENT} for
structure and union fields only, unless the field alignment has been set
by the @code{__attribute__ ((aligned (@var{n})))} construct.
+@end defmac
-@findex ADJUST_FIELD_ALIGN
-@item ADJUST_FIELD_ALIGN (@var{field}, @var{computed})
+@defmac ADJUST_FIELD_ALIGN (@var{field}, @var{computed})
An expression for the alignment of a structure field @var{field} if the
alignment computed in the usual way (including applying of
@code{BIGGEST_ALIGNMENT} and @code{BIGGEST_FIELD_ALIGNMENT} to the
alignment) is @var{computed}. It overrides alignment only if the
field alignment has not been set by the
@code{__attribute__ ((aligned (@var{n})))} construct.
+@end defmac
+
+@defmac MAX_STACK_ALIGNMENT
+Biggest stack alignment guaranteed by the backend. Use this macro
+to specify the maximum alignment of a variable on stack.
+
+If not defined, the default value is @code{STACK_BOUNDARY}.
+
+@c FIXME: The default should be @code{PREFERRED_STACK_BOUNDARY}.
+@c But the fix for PR 32893 indicates that we can only guarantee
+@c maximum stack alignment on stack up to @code{STACK_BOUNDARY}, not
+@c @code{PREFERRED_STACK_BOUNDARY}, if stack alignment isn't supported.
+@end defmac
-@findex MAX_OFILE_ALIGNMENT
-@item MAX_OFILE_ALIGNMENT
+@defmac MAX_OFILE_ALIGNMENT
Biggest alignment supported by the object file format of this machine.
Use this macro to limit the alignment which can be specified using the
@code{__attribute__ ((aligned (@var{n})))} construct. If not defined,
the default value is @code{BIGGEST_ALIGNMENT}.
-@findex DATA_ALIGNMENT
-@item DATA_ALIGNMENT (@var{type}, @var{basic-align})
+On systems that use ELF, the default (in @file{config/elfos.h}) is
+the largest supported 32-bit ELF section alignment representable on
+a 32-bit host e.g. @samp{(((unsigned HOST_WIDEST_INT) 1 << 28) * 8)}.
+On 32-bit ELF the largest supported section alignment in bits is
+@samp{(0x80000000 * 8)}, but this is not representable on 32-bit hosts.
+@end defmac
+
+@defmac DATA_ALIGNMENT (@var{type}, @var{basic-align})
If defined, a C expression to compute the alignment for a variable in
the static store. @var{type} is the data type, and @var{basic-align} is
the alignment that the object would ordinarily have. The value of this
make it all fit in fewer cache lines. Another is to cause character
arrays to be word-aligned so that @code{strcpy} calls that copy
constants to character arrays can be done inline.
+@end defmac
-@findex CONSTANT_ALIGNMENT
-@item CONSTANT_ALIGNMENT (@var{constant}, @var{basic-align})
+@defmac CONSTANT_ALIGNMENT (@var{constant}, @var{basic-align})
If defined, a C expression to compute the alignment given to a constant
that is being placed in memory. @var{constant} is the constant and
@var{basic-align} is the alignment that the object would ordinarily
The typical use of this macro is to increase alignment for string
constants to be word aligned so that @code{strcpy} calls that copy
constants can be done inline.
+@end defmac
-@findex LOCAL_ALIGNMENT
-@item LOCAL_ALIGNMENT (@var{type}, @var{basic-align})
+@defmac LOCAL_ALIGNMENT (@var{type}, @var{basic-align})
If defined, a C expression to compute the alignment for a variable in
the local store. @var{type} is the data type, and @var{basic-align} is
the alignment that the object would ordinarily have. The value of this
One use of this macro is to increase alignment of medium-size data to
make it all fit in fewer cache lines.
+@end defmac
+
+@defmac STACK_SLOT_ALIGNMENT (@var{type}, @var{mode}, @var{basic-align})
+If defined, a C expression to compute the alignment for stack slot.
+@var{type} is the data type, @var{mode} is the widest mode available,
+and @var{basic-align} is the alignment that the slot would ordinarily
+have. The value of this macro is used instead of that alignment to
+align the slot.
+
+If this macro is not defined, then @var{basic-align} is used when
+@var{type} is @code{NULL}. Otherwise, @code{LOCAL_ALIGNMENT} will
+be used.
+
+This macro is to set alignment of stack slot to the maximum alignment
+of all possible modes which the slot may have.
+@end defmac
+
+@defmac LOCAL_DECL_ALIGNMENT (@var{decl})
+If defined, a C expression to compute the alignment for a local
+variable @var{decl}.
+
+If this macro is not defined, then
+@code{LOCAL_ALIGNMENT (TREE_TYPE (@var{decl}), DECL_ALIGN (@var{decl}))}
+is used.
+
+One use of this macro is to increase alignment of medium-size data to
+make it all fit in fewer cache lines.
+@end defmac
+
+@defmac MINIMUM_ALIGNMENT (@var{exp}, @var{mode}, @var{align})
+If defined, a C expression to compute the minimum required alignment
+for dynamic stack realignment purposes for @var{exp} (a type or decl),
+@var{mode}, assuming normal alignment @var{align}.
+
+If this macro is not defined, then @var{align} will be used.
+@end defmac
-@findex EMPTY_FIELD_BOUNDARY
-@item EMPTY_FIELD_BOUNDARY
+@defmac EMPTY_FIELD_BOUNDARY
Alignment in bits to be given to a structure bit-field that follows an
empty field such as @code{int : 0;}.
-Note that @code{PCC_BITFIELD_TYPE_MATTERS} also affects the alignment
-that results from an empty field.
+If @code{PCC_BITFIELD_TYPE_MATTERS} is true, it overrides this macro.
+@end defmac
-@findex STRUCTURE_SIZE_BOUNDARY
-@item STRUCTURE_SIZE_BOUNDARY
+@defmac STRUCTURE_SIZE_BOUNDARY
Number of bits which any structure or union's size must be a multiple of.
Each structure or union's size is rounded up to a multiple of this.
If you do not define this macro, the default is the same as
@code{BITS_PER_UNIT}.
+@end defmac
-@findex STRICT_ALIGNMENT
-@item STRICT_ALIGNMENT
+@defmac STRICT_ALIGNMENT
Define this macro to be the value 1 if instructions will fail to work
if given data not on the nominal alignment. If instructions will merely
go slower in that case, define this macro as 0.
+@end defmac
-@findex PCC_BITFIELD_TYPE_MATTERS
-@item PCC_BITFIELD_TYPE_MATTERS
+@defmac PCC_BITFIELD_TYPE_MATTERS
Define this if you wish to imitate the way many other C compilers handle
alignment of bit-fields and the structures that contain them.
-The behavior is that the type written for a bit-field (@code{int},
-@code{short}, or other integer type) imposes an alignment for the
-entire structure, as if the structure really did contain an ordinary
-field of that type. In addition, the bit-field is placed within the
-structure so that it would fit within such a field, not crossing a
-boundary for it.
+The behavior is that the type written for a named bit-field (@code{int},
+@code{short}, or other integer type) imposes an alignment for the entire
+structure, as if the structure really did contain an ordinary field of
+that type. In addition, the bit-field is placed within the structure so
+that it would fit within such a field, not crossing a boundary for it.
-Thus, on most machines, a bit-field whose type is written as @code{int}
-would not cross a four-byte boundary, and would force four-byte
-alignment for the whole structure. (The alignment used may not be four
-bytes; it is controlled by the other alignment parameters.)
+Thus, on most machines, a named bit-field whose type is written as
+@code{int} would not cross a four-byte boundary, and would force
+four-byte alignment for the whole structure. (The alignment used may
+not be four bytes; it is controlled by the other alignment parameters.)
+
+An unnamed bit-field will not affect the alignment of the containing
+structure.
If the macro is defined, its definition should be a C expression;
a nonzero value for the expression enables this behavior.
bit-fields as are used by another compiler, here is how to investigate
what the other compiler does. Compile and run this program:
-@example
+@smallexample
struct foo1
@{
char x;
sizeof (struct foo2));
exit (0);
@}
-@end example
+@end smallexample
If this prints 2 and 5, then the compiler's behavior is what you would
get from @code{PCC_BITFIELD_TYPE_MATTERS}.
+@end defmac
-@findex BITFIELD_NBYTES_LIMITED
-@item BITFIELD_NBYTES_LIMITED
+@defmac BITFIELD_NBYTES_LIMITED
Like @code{PCC_BITFIELD_TYPE_MATTERS} except that its effect is limited
to aligning a bit-field within the structure.
+@end defmac
-@findex MEMBER_TYPE_FORCES_BLK
-@item MEMBER_TYPE_FORCES_BLK (@var{field})
-Return 1 if a structure or array containing @var{field} should be accessed using
-@code{BLKMODE}.
+@deftypefn {Target Hook} bool TARGET_ALIGN_ANON_BITFIELD (void)
+When @code{PCC_BITFIELD_TYPE_MATTERS} is true this hook will determine
+whether unnamed bitfields affect the alignment of the containing
+structure. The hook should return true if the structure should inherit
+the alignment requirements of an unnamed bitfield's type.
+@end deftypefn
-Normally, this is not needed. See the file @file{c4x.h} for an example
-of how to use this macro to prevent a structure having a floating point
-field from being accessed in an integer mode.
+@deftypefn {Target Hook} bool TARGET_NARROW_VOLATILE_BITFIELD (void)
+This target hook should return @code{true} if accesses to volatile bitfields
+should use the narrowest mode possible. It should return @code{false} if
+these accesses should use the bitfield container type.
+
+The default is @code{!TARGET_STRICT_ALIGN}.
+@end deftypefn
-@findex ROUND_TYPE_SIZE
-@item ROUND_TYPE_SIZE (@var{type}, @var{computed}, @var{specified})
-Define this macro as an expression for the overall size of a type
-(given by @var{type} as a tree node) when the size computed in the
-usual way is @var{computed} and the alignment is @var{specified}.
+@defmac MEMBER_TYPE_FORCES_BLK (@var{field}, @var{mode})
+Return 1 if a structure or array containing @var{field} should be accessed using
+@code{BLKMODE}.
-The default is to round @var{computed} up to a multiple of @var{specified}.
+If @var{field} is the only field in the structure, @var{mode} is its
+mode, otherwise @var{mode} is VOIDmode. @var{mode} is provided in the
+case where structures of one field would require the structure's mode to
+retain the field's mode.
-@findex ROUND_TYPE_SIZE_UNIT
-@item ROUND_TYPE_SIZE_UNIT (@var{type}, @var{computed}, @var{specified})
-Similar to @code{ROUND_TYPE_SIZE}, but sizes and alignments are
-specified in units (bytes). If you define @code{ROUND_TYPE_SIZE},
-you must also define this macro and they must be defined consistently
-with each other.
+Normally, this is not needed.
+@end defmac
-@findex ROUND_TYPE_ALIGN
-@item ROUND_TYPE_ALIGN (@var{type}, @var{computed}, @var{specified})
+@defmac ROUND_TYPE_ALIGN (@var{type}, @var{computed}, @var{specified})
Define this macro as an expression for the alignment of a type (given
by @var{type} as a tree node) if the alignment computed in the usual
way is @var{computed} and the alignment explicitly specified was
The default is to use @var{specified} if it is larger; otherwise, use
the smaller of @var{computed} and @code{BIGGEST_ALIGNMENT}
+@end defmac
-@findex MAX_FIXED_MODE_SIZE
-@item MAX_FIXED_MODE_SIZE
+@defmac MAX_FIXED_MODE_SIZE
An integer expression for the size in bits of the largest integer
machine mode that should actually be used. All integer machine modes of
this size or smaller can be used for structures and unions with the
appropriate sizes. If this macro is undefined, @code{GET_MODE_BITSIZE
(DImode)} is assumed.
+@end defmac
-@findex VECTOR_MODE_SUPPORTED_P
-@item VECTOR_MODE_SUPPORTED_P(@var{mode})
-Define this macro to be nonzero if the port is prepared to handle insns
-involving vector mode @var{mode}. At the very least, it must have move
-patterns for this mode.
-
-@findex STACK_SAVEAREA_MODE
-@item STACK_SAVEAREA_MODE (@var{save_level})
+@defmac STACK_SAVEAREA_MODE (@var{save_level})
If defined, an expression of type @code{enum machine_mode} that
specifies the mode of the save area operand of a
@code{save_stack_@var{level}} named pattern (@pxref{Standard Names}).
would most commonly define this macro if the
@code{save_stack_@var{level}} patterns need to support both a 32- and a
64-bit mode.
+@end defmac
-@findex STACK_SIZE_MODE
-@item STACK_SIZE_MODE
+@defmac STACK_SIZE_MODE
If defined, an expression of type @code{enum machine_mode} that
specifies the mode of the size increment operand of an
@code{allocate_stack} named pattern (@pxref{Standard Names}).
You need not define this macro if it always returns @code{word_mode}.
You would most commonly define this macro if the @code{allocate_stack}
pattern needs to support both a 32- and a 64-bit mode.
+@end defmac
-@findex CHECK_FLOAT_VALUE
-@item CHECK_FLOAT_VALUE (@var{mode}, @var{value}, @var{overflow})
-A C statement to validate the value @var{value} (of type
-@code{double}) for mode @var{mode}. This means that you check whether
-@var{value} fits within the possible range of values for mode
-@var{mode} on this target machine. The mode @var{mode} is always
-a mode of class @code{MODE_FLOAT}. @var{overflow} is nonzero if
-the value is already known to be out of range.
-
-If @var{value} is not valid or if @var{overflow} is nonzero, you should
-set @var{overflow} to 1 and then assign some valid value to @var{value}.
-Allowing an invalid value to go through the compiler can produce
-incorrect assembler code which may even cause Unix assemblers to crash.
-
-This macro need not be defined if there is no work for it to do.
-
-@findex TARGET_FLOAT_FORMAT
-@item TARGET_FLOAT_FORMAT
-A code distinguishing the floating point format of the target machine.
-There are five defined values:
-
-@table @code
-@findex IEEE_FLOAT_FORMAT
-@item IEEE_FLOAT_FORMAT
-This code indicates IEEE floating point. It is the default; there is no
-need to define this macro when the format is IEEE@.
-
-@findex VAX_FLOAT_FORMAT
-@item VAX_FLOAT_FORMAT
-This code indicates the ``D float'' format used on the VAX@.
-
-@findex IBM_FLOAT_FORMAT
-@item IBM_FLOAT_FORMAT
-This code indicates the format used on the IBM System/370.
-
-@findex C4X_FLOAT_FORMAT
-@item C4X_FLOAT_FORMAT
-This code indicates the format used on the TMS320C3x/C4x.
-
-@findex UNKNOWN_FLOAT_FORMAT
-@item UNKNOWN_FLOAT_FORMAT
-This code indicates any other format.
-@end table
+@deftypefn {Target Hook} {enum machine_mode} TARGET_LIBGCC_CMP_RETURN_MODE ()
+This target hook should return the mode to be used for the return value
+of compare instructions expanded to libgcc calls. If not defined
+@code{word_mode} is returned which is the right choice for a majority of
+targets.
+@end deftypefn
+
+@deftypefn {Target Hook} {enum machine_mode} TARGET_LIBGCC_SHIFT_COUNT_MODE ()
+This target hook should return the mode to be used for the shift count operand
+of shift instructions expanded to libgcc calls. If not defined
+@code{word_mode} is returned which is the right choice for a majority of
+targets.
+@end deftypefn
-The value of this macro is compared with @code{HOST_FLOAT_FORMAT}, which
-is defined by the @command{configure} script, to determine whether the
-target machine has the same format as the host machine. If any other
-formats are actually in use on supported machines, new codes should be
-defined for them.
+@defmac ROUND_TOWARDS_ZERO
+If defined, this macro should be true if the prevailing rounding
+mode is towards zero.
-The ordering of the component words of floating point values stored in
-memory is controlled by @code{FLOAT_WORDS_BIG_ENDIAN}.
+Defining this macro only affects the way @file{libgcc.a} emulates
+floating-point arithmetic.
-@end table
+Not defining this macro is equivalent to returning zero.
+@end defmac
+
+@defmac LARGEST_EXPONENT_IS_NORMAL (@var{size})
+This macro should return true if floats with @var{size}
+bits do not have a NaN or infinity representation, but use the largest
+exponent for normal numbers instead.
+
+Defining this macro only affects the way @file{libgcc.a} emulates
+floating-point arithmetic.
+
+The default definition of this macro returns false for all sizes.
+@end defmac
+
+@deftypefn {Target Hook} bool TARGET_VECTOR_OPAQUE_P (tree @var{type})
+This target hook should return @code{true} a vector is opaque. That
+is, if no cast is needed when copying a vector value of type
+@var{type} into another vector lvalue of the same size. Vector opaque
+types cannot be initialized. The default is that there are no such
+types.
+@end deftypefn
@deftypefn {Target Hook} bool TARGET_MS_BITFIELD_LAYOUT_P (tree @var{record_type})
This target hook returns @code{true} if bit-fields in the given
bit-field; (ii) a zero-sized bit-field will affect the alignment of
the whole enclosing structure, even if it is unnamed; except that
(iii) a zero-sized bit-field will be disregarded unless it follows
-another bit-field of non-zero size. If this hook returns @code{true},
+another bit-field of nonzero size. If this hook returns @code{true},
other macros that control bit-field layout are ignored.
+
+When a bit-field is inserted into a packed record, the whole size
+of the underlying type is used by one or more same-size adjacent
+bit-fields (that is, if its long:3, 32 bits is used in the record,
+and any additional adjacent long bit-fields are packed into the same
+chunk of 32 bits. However, if the size changes, a new field of that
+size is allocated). In an unpacked record, this is the same as using
+alignment, but not equivalent when packing.
+
+If both MS bit-fields and @samp{__attribute__((packed))} are used,
+the latter will take precedence. If @samp{__attribute__((packed))} is
+used on a single field when MS bit-fields are in use, it will take
+precedence for that field, but the alignment of the rest of the structure
+may affect its placement.
+@end deftypefn
+
+@deftypefn {Target Hook} {bool} TARGET_DECIMAL_FLOAT_SUPPORTED_P (void)
+Returns true if the target supports decimal floating point.
+@end deftypefn
+
+@deftypefn {Target Hook} {bool} TARGET_FIXED_POINT_SUPPORTED_P (void)
+Returns true if the target supports fixed-point arithmetic.
+@end deftypefn
+
+@deftypefn {Target Hook} void TARGET_EXPAND_TO_RTL_HOOK (void)
+This hook is called just before expansion into rtl, allowing the target
+to perform additional initializations or analysis before the expansion.
+For example, the rs6000 port uses it to allocate a scratch stack slot
+for use in copying SDmode values between memory and floating point
+registers whenever the function being expanded has any SDmode
+usage.
+@end deftypefn
+
+@deftypefn {Target Hook} void TARGET_INSTANTIATE_DECLS (void)
+This hook allows the backend to perform additional instantiations on rtl
+that are not actually in any insns yet, but will be later.
+@end deftypefn
+
+@deftypefn {Target Hook} {const char *} TARGET_MANGLE_TYPE (tree @var{type})
+If your target defines any fundamental types, or any types your target
+uses should be mangled differently from the default, define this hook
+to return the appropriate encoding for these types as part of a C++
+mangled name. The @var{type} argument is the tree structure representing
+the type to be mangled. The hook may be applied to trees which are
+not target-specific fundamental types; it should return @code{NULL}
+for all such types, as well as arguments it does not recognize. If the
+return value is not @code{NULL}, it must point to a statically-allocated
+string constant.
+
+Target-specific fundamental types might be new fundamental types or
+qualified versions of ordinary fundamental types. Encode new
+fundamental types as @samp{@w{u @var{n} @var{name}}}, where @var{name}
+is the name used for the type in source code, and @var{n} is the
+length of @var{name} in decimal. Encode qualified versions of
+ordinary types as @samp{@w{U @var{n} @var{name} @var{code}}}, where
+@var{name} is the name used for the type qualifier in source code,
+@var{n} is the length of @var{name} as above, and @var{code} is the
+code used to represent the unqualified version of this type. (See
+@code{write_builtin_type} in @file{cp/mangle.c} for the list of
+codes.) In both cases the spaces are for clarity; do not include any
+spaces in your string.
+
+This hook is applied to types prior to typedef resolution. If the mangled
+name for a particular type depends only on that type's main variant, you
+can perform typedef resolution yourself using @code{TYPE_MAIN_VARIANT}
+before mangling.
+
+The default version of this hook always returns @code{NULL}, which is
+appropriate for a target that does not define any new fundamental
+types.
@end deftypefn
@node Type Layout
the previous section, these apply to specific features of C and related
languages, rather than to fundamental aspects of storage layout.
-@table @code
-@findex INT_TYPE_SIZE
-@item INT_TYPE_SIZE
+@defmac INT_TYPE_SIZE
A C expression for the size in bits of the type @code{int} on the
target machine. If you don't define this, the default is one word.
+@end defmac
-@findex SHORT_TYPE_SIZE
-@item SHORT_TYPE_SIZE
+@defmac SHORT_TYPE_SIZE
A C expression for the size in bits of the type @code{short} on the
target machine. If you don't define this, the default is half a word.
(If this would be less than one storage unit, it is rounded up to one
unit.)
+@end defmac
-@findex LONG_TYPE_SIZE
-@item LONG_TYPE_SIZE
+@defmac LONG_TYPE_SIZE
A C expression for the size in bits of the type @code{long} on the
target machine. If you don't define this, the default is one word.
+@end defmac
-@findex ADA_LONG_TYPE_SIZE
-@item ADA_LONG_TYPE_SIZE
+@defmac ADA_LONG_TYPE_SIZE
On some machines, the size used for the Ada equivalent of the type
-@code{long} by a native Ada compiler differs from that used by C. In
+@code{long} by a native Ada compiler differs from that used by C@. In
that situation, define this macro to be a C expression to be used for
the size of that type. If you don't define this, the default is the
value of @code{LONG_TYPE_SIZE}.
+@end defmac
-@findex MAX_LONG_TYPE_SIZE
-@item MAX_LONG_TYPE_SIZE
-Maximum number for the size in bits of the type @code{long} on the
-target machine. If this is undefined, the default is
-@code{LONG_TYPE_SIZE}. Otherwise, it is the constant value that is the
-largest value that @code{LONG_TYPE_SIZE} can have at run-time. This is
-used in @code{cpp}.
-
-@findex LONG_LONG_TYPE_SIZE
-@item LONG_LONG_TYPE_SIZE
+@defmac LONG_LONG_TYPE_SIZE
A C expression for the size in bits of the type @code{long long} on the
target machine. If you don't define this, the default is two
words. If you want to support GNU Ada on your machine, the value of this
macro must be at least 64.
+@end defmac
-@findex CHAR_TYPE_SIZE
-@item CHAR_TYPE_SIZE
+@defmac CHAR_TYPE_SIZE
A C expression for the size in bits of the type @code{char} on the
target machine. If you don't define this, the default is
@code{BITS_PER_UNIT}.
+@end defmac
-@findex MAX_CHAR_TYPE_SIZE
-@item MAX_CHAR_TYPE_SIZE
-Maximum number for the size in bits of the type @code{char} on the
-target machine. If this is undefined, the default is
-@code{CHAR_TYPE_SIZE}. Otherwise, it is the constant value that is the
-largest value that @code{CHAR_TYPE_SIZE} can have at run-time. This is
-used in @code{cpp}.
-
-@findex BOOL_TYPE_SIZE
-@item BOOL_TYPE_SIZE
+@defmac BOOL_TYPE_SIZE
A C expression for the size in bits of the C++ type @code{bool} and
C99 type @code{_Bool} on the target machine. If you don't define
this, and you probably shouldn't, the default is @code{CHAR_TYPE_SIZE}.
+@end defmac
-@findex FLOAT_TYPE_SIZE
-@item FLOAT_TYPE_SIZE
+@defmac FLOAT_TYPE_SIZE
A C expression for the size in bits of the type @code{float} on the
target machine. If you don't define this, the default is one word.
+@end defmac
-@findex DOUBLE_TYPE_SIZE
-@item DOUBLE_TYPE_SIZE
+@defmac DOUBLE_TYPE_SIZE
A C expression for the size in bits of the type @code{double} on the
target machine. If you don't define this, the default is two
words.
+@end defmac
-@findex LONG_DOUBLE_TYPE_SIZE
-@item LONG_DOUBLE_TYPE_SIZE
+@defmac LONG_DOUBLE_TYPE_SIZE
A C expression for the size in bits of the type @code{long double} on
the target machine. If you don't define this, the default is two
words.
+@end defmac
-@findex MAX_LONG_DOUBLE_TYPE_SIZE
-Maximum number for the size in bits of the type @code{long double} on the
-target machine. If this is undefined, the default is
-@code{LONG_DOUBLE_TYPE_SIZE}. Otherwise, it is the constant value that is
-the largest value that @code{LONG_DOUBLE_TYPE_SIZE} can have at run-time.
-This is used in @code{cpp}.
-
-@findex INTEL_EXTENDED_IEEE_FORMAT
-Define this macro to be 1 if the target machine uses 80-bit floating-point
-values with 128-bit size and alignment. This is used in @file{real.c}.
-
-@findex WIDEST_HARDWARE_FP_SIZE
-@item WIDEST_HARDWARE_FP_SIZE
+@defmac SHORT_FRACT_TYPE_SIZE
+A C expression for the size in bits of the type @code{short _Fract} on
+the target machine. If you don't define this, the default is
+@code{BITS_PER_UNIT}.
+@end defmac
+
+@defmac FRACT_TYPE_SIZE
+A C expression for the size in bits of the type @code{_Fract} on
+the target machine. If you don't define this, the default is
+@code{BITS_PER_UNIT * 2}.
+@end defmac
+
+@defmac LONG_FRACT_TYPE_SIZE
+A C expression for the size in bits of the type @code{long _Fract} on
+the target machine. If you don't define this, the default is
+@code{BITS_PER_UNIT * 4}.
+@end defmac
+
+@defmac LONG_LONG_FRACT_TYPE_SIZE
+A C expression for the size in bits of the type @code{long long _Fract} on
+the target machine. If you don't define this, the default is
+@code{BITS_PER_UNIT * 8}.
+@end defmac
+
+@defmac SHORT_ACCUM_TYPE_SIZE
+A C expression for the size in bits of the type @code{short _Accum} on
+the target machine. If you don't define this, the default is
+@code{BITS_PER_UNIT * 2}.
+@end defmac
+
+@defmac ACCUM_TYPE_SIZE
+A C expression for the size in bits of the type @code{_Accum} on
+the target machine. If you don't define this, the default is
+@code{BITS_PER_UNIT * 4}.
+@end defmac
+
+@defmac LONG_ACCUM_TYPE_SIZE
+A C expression for the size in bits of the type @code{long _Accum} on
+the target machine. If you don't define this, the default is
+@code{BITS_PER_UNIT * 8}.
+@end defmac
+
+@defmac LONG_LONG_ACCUM_TYPE_SIZE
+A C expression for the size in bits of the type @code{long long _Accum} on
+the target machine. If you don't define this, the default is
+@code{BITS_PER_UNIT * 16}.
+@end defmac
+
+@defmac LIBGCC2_LONG_DOUBLE_TYPE_SIZE
+Define this macro if @code{LONG_DOUBLE_TYPE_SIZE} is not constant or
+if you want routines in @file{libgcc2.a} for a size other than
+@code{LONG_DOUBLE_TYPE_SIZE}. If you don't define this, the
+default is @code{LONG_DOUBLE_TYPE_SIZE}.
+@end defmac
+
+@defmac LIBGCC2_HAS_DF_MODE
+Define this macro if neither @code{LIBGCC2_DOUBLE_TYPE_SIZE} nor
+@code{LIBGCC2_LONG_DOUBLE_TYPE_SIZE} is
+@code{DFmode} but you want @code{DFmode} routines in @file{libgcc2.a}
+anyway. If you don't define this and either @code{LIBGCC2_DOUBLE_TYPE_SIZE}
+or @code{LIBGCC2_LONG_DOUBLE_TYPE_SIZE} is 64 then the default is 1,
+otherwise it is 0.
+@end defmac
+
+@defmac LIBGCC2_HAS_XF_MODE
+Define this macro if @code{LIBGCC2_LONG_DOUBLE_TYPE_SIZE} is not
+@code{XFmode} but you want @code{XFmode} routines in @file{libgcc2.a}
+anyway. If you don't define this and @code{LIBGCC2_LONG_DOUBLE_TYPE_SIZE}
+is 80 then the default is 1, otherwise it is 0.
+@end defmac
+
+@defmac LIBGCC2_HAS_TF_MODE
+Define this macro if @code{LIBGCC2_LONG_DOUBLE_TYPE_SIZE} is not
+@code{TFmode} but you want @code{TFmode} routines in @file{libgcc2.a}
+anyway. If you don't define this and @code{LIBGCC2_LONG_DOUBLE_TYPE_SIZE}
+is 128 then the default is 1, otherwise it is 0.
+@end defmac
+
+@defmac SF_SIZE
+@defmacx DF_SIZE
+@defmacx XF_SIZE
+@defmacx TF_SIZE
+Define these macros to be the size in bits of the mantissa of
+@code{SFmode}, @code{DFmode}, @code{XFmode} and @code{TFmode} values,
+if the defaults in @file{libgcc2.h} are inappropriate. By default,
+@code{FLT_MANT_DIG} is used for @code{SF_SIZE}, @code{LDBL_MANT_DIG}
+for @code{XF_SIZE} and @code{TF_SIZE}, and @code{DBL_MANT_DIG} or
+@code{LDBL_MANT_DIG} for @code{DF_SIZE} according to whether
+@code{LIBGCC2_DOUBLE_TYPE_SIZE} or
+@code{LIBGCC2_LONG_DOUBLE_TYPE_SIZE} is 64.
+@end defmac
+
+@defmac TARGET_FLT_EVAL_METHOD
+A C expression for the value for @code{FLT_EVAL_METHOD} in @file{float.h},
+assuming, if applicable, that the floating-point control word is in its
+default state. If you do not define this macro the value of
+@code{FLT_EVAL_METHOD} will be zero.
+@end defmac
+
+@defmac WIDEST_HARDWARE_FP_SIZE
A C expression for the size in bits of the widest floating-point format
supported by the hardware. If you define this macro, you must specify a
value less than or equal to the value of @code{LONG_DOUBLE_TYPE_SIZE}.
If you do not define this macro, the value of @code{LONG_DOUBLE_TYPE_SIZE}
is the default.
+@end defmac
-@findex DEFAULT_SIGNED_CHAR
-@item DEFAULT_SIGNED_CHAR
+@defmac DEFAULT_SIGNED_CHAR
An expression whose value is 1 or 0, according to whether the type
@code{char} should be signed or unsigned by default. The user can
always override this default with the options @option{-fsigned-char}
and @option{-funsigned-char}.
+@end defmac
-@findex DEFAULT_SHORT_ENUMS
-@item DEFAULT_SHORT_ENUMS
-A C expression to determine whether to give an @code{enum} type
-only as many bytes as it takes to represent the range of possible values
-of that type. A nonzero value means to do that; a zero value means all
+@deftypefn {Target Hook} bool TARGET_DEFAULT_SHORT_ENUMS (void)
+This target hook should return true if the compiler should give an
+@code{enum} type only as many bytes as it takes to represent the range
+of possible values of that type. It should return false if all
@code{enum} types should be allocated like @code{int}.
-If you don't define the macro, the default is 0.
+The default is to return false.
+@end deftypefn
-@findex SIZE_TYPE
-@item SIZE_TYPE
+@defmac SIZE_TYPE
A C expression for a string describing the name of the data type to use
for size values. The typedef name @code{size_t} is defined using the
contents of the string.
If you don't define this macro, the default is @code{"long unsigned
int"}.
+@end defmac
-@findex PTRDIFF_TYPE
-@item PTRDIFF_TYPE
+@defmac PTRDIFF_TYPE
A C expression for a string describing the name of the data type to use
for the result of subtracting two pointers. The typedef name
@code{ptrdiff_t} is defined using the contents of the string. See
@code{SIZE_TYPE} above for more information.
If you don't define this macro, the default is @code{"long int"}.
+@end defmac
-@findex WCHAR_TYPE
-@item WCHAR_TYPE
+@defmac WCHAR_TYPE
A C expression for a string describing the name of the data type to use
for wide characters. The typedef name @code{wchar_t} is defined using
the contents of the string. See @code{SIZE_TYPE} above for more
information.
If you don't define this macro, the default is @code{"int"}.
+@end defmac
-@findex WCHAR_TYPE_SIZE
-@item WCHAR_TYPE_SIZE
+@defmac WCHAR_TYPE_SIZE
A C expression for the size in bits of the data type for wide
characters. This is used in @code{cpp}, which cannot make use of
@code{WCHAR_TYPE}.
+@end defmac
-@findex MAX_WCHAR_TYPE_SIZE
-@item MAX_WCHAR_TYPE_SIZE
-Maximum number for the size in bits of the data type for wide
-characters. If this is undefined, the default is
-@code{WCHAR_TYPE_SIZE}. Otherwise, it is the constant value that is the
-largest value that @code{WCHAR_TYPE_SIZE} can have at run-time. This is
-used in @code{cpp}.
-
-@findex GCOV_TYPE_SIZE
-@item GCOV_TYPE_SIZE
-A C expression for the size in bits of the type used for gcov counters on the
-target machine. If you don't define this, the default is one
-@code{LONG_TYPE_SIZE} in case it is greater or equal to 64-bit and
-@code{LONG_LONG_TYPE_SIZE} otherwise. You may want to re-define the type to
-ensure atomicity for counters in multithreaded programs.
-
-@findex WINT_TYPE
-@item WINT_TYPE
+@defmac WINT_TYPE
A C expression for a string describing the name of the data type to
use for wide characters passed to @code{printf} and returned from
@code{getwc}. The typedef name @code{wint_t} is defined using the
information.
If you don't define this macro, the default is @code{"unsigned int"}.
+@end defmac
-@findex INTMAX_TYPE
-@item INTMAX_TYPE
+@defmac INTMAX_TYPE
A C expression for a string describing the name of the data type that
can represent any value of any standard or extended signed integer type.
The typedef name @code{intmax_t} is defined using the contents of the
If you don't define this macro, the default is the first of
@code{"int"}, @code{"long int"}, or @code{"long long int"} that has as
much precision as @code{long long int}.
+@end defmac
-@findex UINTMAX_TYPE
-@item UINTMAX_TYPE
+@defmac UINTMAX_TYPE
A C expression for a string describing the name of the data type that
can represent any value of any standard or extended unsigned integer
type. The typedef name @code{uintmax_t} is defined using the contents
@code{"unsigned int"}, @code{"long unsigned int"}, or @code{"long long
unsigned int"} that has as much precision as @code{long long unsigned
int}.
+@end defmac
-@findex TARGET_PTRMEMFUNC_VBIT_LOCATION
-@item TARGET_PTRMEMFUNC_VBIT_LOCATION
+@defmac TARGET_PTRMEMFUNC_VBIT_LOCATION
The C++ compiler represents a pointer-to-member-function with a struct
that looks like:
-@example
+@smallexample
struct @{
union @{
void (*fn)();
@};
ptrdiff_t delta;
@};
-@end example
+@end smallexample
@noindent
The C++ compiler must use one bit to indicate whether the function that
in which function addresses are always even, according to
@code{FUNCTION_BOUNDARY}, GCC will automatically define this macro to
@code{ptrmemfunc_vbit_in_pfn}.
+@end defmac
-@findex TARGET_VTABLE_USES_DESCRIPTORS
-@item TARGET_VTABLE_USES_DESCRIPTORS
+@defmac TARGET_VTABLE_USES_DESCRIPTORS
Normally, the C++ compiler uses function pointers in vtables. This
macro allows the target to change to use ``function descriptors''
instead. Function descriptors are found on targets for whom a
If vtables are used, the value of this macro should be the number
of words that the function descriptor occupies.
-@end table
-
-@node Escape Sequences
-@section Target Character Escape Sequences
-@cindex escape sequences
-
-By default, GCC assumes that the C character escape sequences take on
-their ASCII values for the target. If this is not correct, you must
-explicitly define all of the macros below.
-
-@table @code
-@findex TARGET_BELL
-@item TARGET_BELL
-A C constant expression for the integer value for escape sequence
-@samp{\a}.
-
-@findex TARGET_ESC
-@item TARGET_ESC
-A C constant expression for the integer value of the target escape
-character. As an extension, GCC evaluates the escape sequences
-@samp{\e} and @samp{\E} to this.
-
-@findex TARGET_TAB
-@findex TARGET_BS
-@findex TARGET_NEWLINE
-@item TARGET_BS
-@itemx TARGET_TAB
-@itemx TARGET_NEWLINE
-C constant expressions for the integer values for escape sequences
-@samp{\b}, @samp{\t} and @samp{\n}.
-
-@findex TARGET_VT
-@findex TARGET_FF
-@findex TARGET_CR
-@item TARGET_VT
-@itemx TARGET_FF
-@itemx TARGET_CR
-C constant expressions for the integer values for escape sequences
-@samp{\v}, @samp{\f} and @samp{\r}.
-@end table
+@end defmac
+
+@defmac TARGET_VTABLE_ENTRY_ALIGN
+By default, the vtable entries are void pointers, the so the alignment
+is the same as pointer alignment. The value of this macro specifies
+the alignment of the vtable entry in bits. It should be defined only
+when special alignment is necessary. */
+@end defmac
+
+@defmac TARGET_VTABLE_DATA_ENTRY_DISTANCE
+There are a few non-descriptor entries in the vtable at offsets below
+zero. If these entries must be padded (say, to preserve the alignment
+specified by @code{TARGET_VTABLE_ENTRY_ALIGN}), set this to the number
+of words in each data entry.
+@end defmac
@node Registers
@section Register Usage
For returning values in registers, see @ref{Scalar Return}.
@menu
-* Register Basics:: Number and kinds of registers.
-* Allocation Order:: Order in which registers are allocated.
-* Values in Registers:: What kinds of values each reg can hold.
-* Leaf Functions:: Renumbering registers for leaf functions.
-* Stack Registers:: Handling a register stack such as 80387.
+* Register Basics:: Number and kinds of registers.
+* Allocation Order:: Order in which registers are allocated.
+* Values in Registers:: What kinds of values each reg can hold.
+* Leaf Functions:: Renumbering registers for leaf functions.
+* Stack Registers:: Handling a register stack such as 80387.
@end menu
@node Register Basics
@c prevent bad page break with this line
Registers have various characteristics.
-@table @code
-@findex FIRST_PSEUDO_REGISTER
-@item FIRST_PSEUDO_REGISTER
+@defmac FIRST_PSEUDO_REGISTER
Number of hardware registers known to the compiler. They receive
numbers 0 through @code{FIRST_PSEUDO_REGISTER-1}; thus, the first
pseudo register's number really is assigned the number
@code{FIRST_PSEUDO_REGISTER}.
+@end defmac
-@item FIXED_REGISTERS
-@findex FIXED_REGISTERS
+@defmac FIXED_REGISTERS
@cindex fixed register
An initializer that says which registers are used for fixed purposes
all throughout the compiled code and are therefore not available for
by the actions of the macro @code{CONDITIONAL_REGISTER_USAGE}, or by
the user with the command options @option{-ffixed-@var{reg}},
@option{-fcall-used-@var{reg}} and @option{-fcall-saved-@var{reg}}.
+@end defmac
-@findex CALL_USED_REGISTERS
-@item CALL_USED_REGISTERS
+@defmac CALL_USED_REGISTERS
@cindex call-used register
@cindex call-clobbered register
@cindex call-saved register
If a register has 0 in @code{CALL_USED_REGISTERS}, the compiler
automatically saves it on function entry and restores it on function
exit, if the register is used within the function.
+@end defmac
-@findex CALL_REALLY_USED_REGISTERS
-@item CALL_REALLY_USED_REGISTERS
+@defmac CALL_REALLY_USED_REGISTERS
@cindex call-used register
@cindex call-clobbered register
@cindex call-saved register
(@code{CALL_USED_REGISTERS} must be a superset of @code{FIXED_REGISTERS}).
This macro is optional. If not specified, it defaults to the value
of @code{CALL_USED_REGISTERS}.
+@end defmac
-@findex HARD_REGNO_CALL_PART_CLOBBERED
-@item HARD_REGNO_CALL_PART_CLOBBERED (@var{regno}, @var{mode})
+@defmac HARD_REGNO_CALL_PART_CLOBBERED (@var{regno}, @var{mode})
@cindex call-used register
@cindex call-clobbered register
@cindex call-saved register
call without some part of it being clobbered. For most machines this
macro need not be defined. It is only required for machines that do not
preserve the entire contents of a register across a call.
+@end defmac
-@findex CONDITIONAL_REGISTER_USAGE
@findex fixed_regs
@findex call_used_regs
-@item CONDITIONAL_REGISTER_USAGE
+@findex global_regs
+@findex reg_names
+@findex reg_class_contents
+@defmac CONDITIONAL_REGISTER_USAGE
Zero or more C statements that may conditionally modify five variables
@code{fixed_regs}, @code{call_used_regs}, @code{global_regs},
@code{reg_names}, and @code{reg_class_contents}, to take into account
flags, you may indicate this to GCC by using this macro to modify
@code{fixed_regs} and @code{call_used_regs} to 1 for each of the
registers in the classes which should not be used by GCC@. Also define
-the macro @code{REG_CLASS_FROM_LETTER} to return @code{NO_REGS} if it
+the macro @code{REG_CLASS_FROM_LETTER} / @code{REG_CLASS_FROM_CONSTRAINT}
+to return @code{NO_REGS} if it
is called with a letter for a class that shouldn't be used.
(However, if this class is not included in @code{GENERAL_REGS} and all
of the insn patterns whose constraints permit this class are
controlled by target switches, then GCC will automatically avoid using
these registers when the target switches are opposed to them.)
+@end defmac
-@findex NON_SAVING_SETJMP
-@item NON_SAVING_SETJMP
-If this macro is defined and has a nonzero value, it means that
-@code{setjmp} and related functions fail to save the registers, or that
-@code{longjmp} fails to restore them. To compensate, the compiler
-avoids putting variables in registers in functions that use
-@code{setjmp}.
-
-@findex INCOMING_REGNO
-@item INCOMING_REGNO (@var{out})
+@defmac INCOMING_REGNO (@var{out})
Define this macro if the target machine has register windows. This C
expression returns the register number as seen by the called function
corresponding to the register number @var{out} as seen by the calling
function. Return @var{out} if register number @var{out} is not an
outbound register.
+@end defmac
-@findex OUTGOING_REGNO
-@item OUTGOING_REGNO (@var{in})
+@defmac OUTGOING_REGNO (@var{in})
Define this macro if the target machine has register windows. This C
expression returns the register number as seen by the calling function
corresponding to the register number @var{in} as seen by the called
function. Return @var{in} if register number @var{in} is not an inbound
register.
+@end defmac
-@findex LOCAL_REGNO
-@item LOCAL_REGNO (@var{regno})
+@defmac LOCAL_REGNO (@var{regno})
Define this macro if the target machine has register windows. This C
expression returns true if the register is call-saved but is in the
register window. Unlike most call-saved registers, such registers
need not be explicitly restored on function exit or during non-local
gotos.
+@end defmac
-@ignore
-@findex PC_REGNUM
-@item PC_REGNUM
+@defmac PC_REGNUM
If the program counter has a register number, define this as that
register number. Otherwise, do not define it.
-@end ignore
-@end table
+@end defmac
@node Allocation Order
@subsection Order of Allocation of Registers
@c prevent bad page break with this line
Registers are allocated in order.
-@table @code
-@findex REG_ALLOC_ORDER
-@item REG_ALLOC_ORDER
+@defmac REG_ALLOC_ORDER
If defined, an initializer for a vector of integers, containing the
numbers of hard registers in the order in which GCC should prefer
to use them (from most preferred to least).
instruction supports only sequences of consecutive registers. On such
machines, define @code{REG_ALLOC_ORDER} to be an initializer that lists
the highest numbered allocable register first.
+@end defmac
-@findex ORDER_REGS_FOR_LOCAL_ALLOC
-@item ORDER_REGS_FOR_LOCAL_ALLOC
+@defmac ORDER_REGS_FOR_LOCAL_ALLOC
A C statement (sans semicolon) to choose the order in which to allocate
hard registers for pseudo-registers local to a basic block.
@code{reg_alloc_order} before execution of the macro.
On most machines, it is not necessary to define this macro.
-@end table
+@end defmac
+
+@defmac IRA_HARD_REGNO_ADD_COST_MULTIPLIER (@var{regno})
+In some case register allocation order is not enough for the
+Integrated Register Allocator (@acronym{IRA}) to generate a good code.
+If this macro is defined, it should return a floating point value
+based on @var{regno}. The cost of using @var{regno} for a pseudo will
+be increased by approximately the pseudo's usage frequency times the
+value returned by this macro. Not defining this macro is equivalent
+to having it always return @code{0.0}.
+
+On most machines, it is not necessary to define this macro.
+@end defmac
@node Values in Registers
@subsection How Values Fit in Registers
(specifically, which machine modes) each register can hold, and how many
consecutive registers are needed for a given mode.
-@table @code
-@findex HARD_REGNO_NREGS
-@item HARD_REGNO_NREGS (@var{regno}, @var{mode})
+@defmac HARD_REGNO_NREGS (@var{regno}, @var{mode})
A C expression for the number of consecutive hard registers, starting
at register number @var{regno}, required to hold a value of mode
-@var{mode}.
+@var{mode}. This macro must never return zero, even if a register
+cannot hold the requested mode - indicate that with HARD_REGNO_MODE_OK
+and/or CANNOT_CHANGE_MODE_CLASS instead.
On a machine where all registers are exactly one word, a suitable
definition of this macro is
((GET_MODE_SIZE (MODE) + UNITS_PER_WORD - 1) \
/ UNITS_PER_WORD)
@end smallexample
-
-@findex HARD_REGNO_MODE_OK
-@item HARD_REGNO_MODE_OK (@var{regno}, @var{mode})
+@end defmac
+
+@defmac HARD_REGNO_NREGS_HAS_PADDING (@var{regno}, @var{mode})
+A C expression that is nonzero if a value of mode @var{mode}, stored
+in memory, ends with padding that causes it to take up more space than
+in registers starting at register number @var{regno} (as determined by
+multiplying GCC's notion of the size of the register when containing
+this mode by the number of registers returned by
+@code{HARD_REGNO_NREGS}). By default this is zero.
+
+For example, if a floating-point value is stored in three 32-bit
+registers but takes up 128 bits in memory, then this would be
+nonzero.
+
+This macros only needs to be defined if there are cases where
+@code{subreg_get_info}
+would otherwise wrongly determine that a @code{subreg} can be
+represented by an offset to the register number, when in fact such a
+@code{subreg} would contain some of the padding not stored in
+registers and so not be representable.
+@end defmac
+
+@defmac HARD_REGNO_NREGS_WITH_PADDING (@var{regno}, @var{mode})
+For values of @var{regno} and @var{mode} for which
+@code{HARD_REGNO_NREGS_HAS_PADDING} returns nonzero, a C expression
+returning the greater number of registers required to hold the value
+including any padding. In the example above, the value would be four.
+@end defmac
+
+@defmac REGMODE_NATURAL_SIZE (@var{mode})
+Define this macro if the natural size of registers that hold values
+of mode @var{mode} is not the word size. It is a C expression that
+should give the natural size in bytes for the specified mode. It is
+used by the register allocator to try to optimize its results. This
+happens for example on SPARC 64-bit where the natural size of
+floating-point registers is still 32-bit.
+@end defmac
+
+@defmac HARD_REGNO_MODE_OK (@var{regno}, @var{mode})
A C expression that is nonzero if it is permissible to store a value
of mode @var{mode} in hard register number @var{regno} (or in several
registers starting with that one). For a machine where all registers
register if floating point arithmetic is not being done. As long as the
floating registers are not in class @code{GENERAL_REGS}, they will not
be used unless some pattern's constraint asks for one.
+@end defmac
+
+@defmac HARD_REGNO_RENAME_OK (@var{from}, @var{to})
+A C expression that is nonzero if it is OK to rename a hard register
+@var{from} to another hard register @var{to}.
+
+One common use of this macro is to prevent renaming of a register to
+another register that is not saved by a prologue in an interrupt
+handler.
-@findex MODES_TIEABLE_P
-@item MODES_TIEABLE_P (@var{mode1}, @var{mode2})
+The default is always nonzero.
+@end defmac
+
+@defmac MODES_TIEABLE_P (@var{mode1}, @var{mode2})
A C expression that is nonzero if a value of mode
@var{mode1} is accessible in mode @var{mode2} without copying.
You should define this macro to return nonzero in as many cases as
possible since doing so will allow GCC to perform better register
allocation.
+@end defmac
+
+@deftypefn {Target Hook} bool TARGET_HARD_REGNO_SCRATCH_OK (unsigned int @var{regno})
+This target hook should return @code{true} if it is OK to use a hard register
+@var{regno} as scratch reg in peephole2.
+
+One common use of this macro is to prevent using of a register that
+is not saved by a prologue in an interrupt handler.
+
+The default version of this hook always returns @code{true}.
+@end deftypefn
-@findex AVOID_CCMODE_COPIES
-@item AVOID_CCMODE_COPIES
+@defmac AVOID_CCMODE_COPIES
Define this macro if the compiler should avoid copies to/from @code{CCmode}
registers. You should only define this macro if support for copying to/from
@code{CCmode} is incomplete.
-@end table
+@end defmac
@node Leaf Functions
@subsection Handling Leaf Functions
registers in order to output a leaf function. The following macros
accomplish this.
-@table @code
-@findex LEAF_REGISTERS
-@item LEAF_REGISTERS
+@defmac LEAF_REGISTERS
Name of a char vector, indexed by hard register number, which
contains 1 for a register that is allowable in a candidate for leaf
function treatment.
Define this macro only if the target machine offers a way to optimize
the treatment of leaf functions.
+@end defmac
-@findex LEAF_REG_REMAP
-@item LEAF_REG_REMAP (@var{regno})
+@defmac LEAF_REG_REMAP (@var{regno})
A C expression whose value is the register number to which @var{regno}
should be renumbered, when a function is treated as a leaf function.
Define this macro only if the target machine offers a way to optimize the
treatment of leaf functions, and registers need to be renumbered to do
this.
-@end table
+@end defmac
@findex current_function_is_leaf
@findex current_function_uses_only_leaf_regs
compiler passes. They can also test the C variable
@code{current_function_uses_only_leaf_regs} which is nonzero for leaf
functions which only use leaf registers.
-@code{current_function_uses_only_leaf_regs} is valid after reload and is
-only useful if @code{LEAF_REGISTERS} is defined.
+@code{current_function_uses_only_leaf_regs} is valid after all passes
+that modify the instructions have been run and is only useful if
+@code{LEAF_REGISTERS} is defined.
@c changed this to fix overfull. ALSO: why the "it" at the beginning
@c of the next paragraph?! --mew 2feb93
@subsection Registers That Form a Stack
There are special features to handle computers where some of the
-``registers'' form a stack, as in the 80387 coprocessor for the 80386.
-Stack registers are normally written by pushing onto the stack, and are
-numbered relative to the top of the stack.
+``registers'' form a stack. Stack registers are normally written by
+pushing onto the stack, and are numbered relative to the top of the
+stack.
Currently, GCC can only handle one group of stack-like registers, and
-they must be consecutively numbered.
-
-@table @code
-@findex STACK_REGS
-@item STACK_REGS
+they must be consecutively numbered. Furthermore, the existing
+support for stack-like registers is specific to the 80387 floating
+point coprocessor. If you have a new architecture that uses
+stack-like registers, you will need to do substantial work on
+@file{reg-stack.c} and write your machine description to cooperate
+with it, as well as defining these macros.
+
+@defmac STACK_REGS
Define this if the machine has any stack-like registers.
+@end defmac
-@findex FIRST_STACK_REG
-@item FIRST_STACK_REG
+@defmac FIRST_STACK_REG
The number of the first stack-like register. This one is the top
of the stack.
+@end defmac
-@findex LAST_STACK_REG
-@item LAST_STACK_REG
+@defmac LAST_STACK_REG
The number of the last stack-like register. This one is the bottom of
the stack.
-@end table
+@end defmac
@node Register Classes
@section Register Classes
single-byte values can be loaded or stored. This is so that
@code{PREFERRED_RELOAD_CLASS} can always have a possible value to return.
-@table @code
-@findex enum reg_class
-@item enum reg_class
-An enumeral type that must be defined with all the register class names
-as enumeral values. @code{NO_REGS} must be first. @code{ALL_REGS}
-must be the last register class, followed by one more enumeral value,
+@deftp {Data type} {enum reg_class}
+An enumerated type that must be defined with all the register class names
+as enumerated values. @code{NO_REGS} must be first. @code{ALL_REGS}
+must be the last register class, followed by one more enumerated value,
@code{LIM_REG_CLASSES}, which is not a register class but rather
tells how many classes there are.
Each register class has a number, which is the value of casting
the class name to type @code{int}. The number serves as an index
in many of the tables described below.
+@end deftp
-@findex N_REG_CLASSES
-@item N_REG_CLASSES
+@defmac N_REG_CLASSES
The number of distinct register classes, defined as follows:
-@example
+@smallexample
#define N_REG_CLASSES (int) LIM_REG_CLASSES
-@end example
+@end smallexample
+@end defmac
-@findex REG_CLASS_NAMES
-@item REG_CLASS_NAMES
+@defmac REG_CLASS_NAMES
An initializer containing the names of the register classes as C string
constants. These names are used in writing some of the debugging dumps.
+@end defmac
-@findex REG_CLASS_CONTENTS
-@item REG_CLASS_CONTENTS
+@defmac REG_CLASS_CONTENTS
An initializer containing the contents of the register classes, as integers
which are bit masks. The @var{n}th integer specifies the contents of class
@var{n}. The way the integer @var{mask} is interpreted is that
In this situation, the first integer in each sub-initializer corresponds to
registers 0 through 31, the second integer to registers 32 through 63, and
so on.
+@end defmac
-@findex REGNO_REG_CLASS
-@item REGNO_REG_CLASS (@var{regno})
+@defmac REGNO_REG_CLASS (@var{regno})
A C expression whose value is a register class containing hard register
@var{regno}. In general there is more than one such class; choose a class
which is @dfn{minimal}, meaning that no smaller class also contains the
register.
+@end defmac
-@findex BASE_REG_CLASS
-@item BASE_REG_CLASS
+@defmac BASE_REG_CLASS
A macro whose definition is the name of the class to which a valid
base register must belong. A base register is one used in an address
which is the register value plus a displacement.
+@end defmac
-@findex MODE_BASE_REG_CLASS
-@item MODE_BASE_REG_CLASS (@var{mode})
+@defmac MODE_BASE_REG_CLASS (@var{mode})
This is a variation of the @code{BASE_REG_CLASS} macro which allows
-the selection of a base register in a mode depenedent manner. If
+the selection of a base register in a mode dependent manner. If
@var{mode} is VOIDmode then it should return the same value as
@code{BASE_REG_CLASS}.
-
-@findex INDEX_REG_CLASS
-@item INDEX_REG_CLASS
+@end defmac
+
+@defmac MODE_BASE_REG_REG_CLASS (@var{mode})
+A C expression whose value is the register class to which a valid
+base register must belong in order to be used in a base plus index
+register address. You should define this macro if base plus index
+addresses have different requirements than other base register uses.
+@end defmac
+
+@defmac MODE_CODE_BASE_REG_CLASS (@var{mode}, @var{outer_code}, @var{index_code})
+A C expression whose value is the register class to which a valid
+base register must belong. @var{outer_code} and @var{index_code} define the
+context in which the base register occurs. @var{outer_code} is the code of
+the immediately enclosing expression (@code{MEM} for the top level of an
+address, @code{ADDRESS} for something that occurs in an
+@code{address_operand}). @var{index_code} is the code of the corresponding
+index expression if @var{outer_code} is @code{PLUS}; @code{SCRATCH} otherwise.
+@end defmac
+
+@defmac INDEX_REG_CLASS
A macro whose definition is the name of the class to which a valid
index register must belong. An index register is one used in an
address where its value is either multiplied by a scale factor or
added to another register (as well as added to a displacement).
+@end defmac
-@findex REG_CLASS_FROM_LETTER
-@item REG_CLASS_FROM_LETTER (@var{char})
-A C expression which defines the machine-dependent operand constraint
-letters for register classes. If @var{char} is such a letter, the
-value should be the register class corresponding to it. Otherwise,
-the value should be @code{NO_REGS}. The register letter @samp{r},
-corresponding to class @code{GENERAL_REGS}, will not be passed
-to this macro; you do not need to handle it.
-
-@findex REGNO_OK_FOR_BASE_P
-@item REGNO_OK_FOR_BASE_P (@var{num})
+@defmac REGNO_OK_FOR_BASE_P (@var{num})
A C expression which is nonzero if register number @var{num} is
suitable for use as a base register in operand addresses. It may be
either a suitable hard register or a pseudo register that has been
allocated such a hard register.
+@end defmac
-@findex REGNO_MODE_OK_FOR_BASE_P
-@item REGNO_MODE_OK_FOR_BASE_P (@var{num}, @var{mode})
+@defmac REGNO_MODE_OK_FOR_BASE_P (@var{num}, @var{mode})
A C expression that is just like @code{REGNO_OK_FOR_BASE_P}, except that
that expression may examine the mode of the memory reference in
@var{mode}. You should define this macro if the mode of the memory
reference affects whether a register may be used as a base register. If
you define this macro, the compiler will use it instead of
-@code{REGNO_OK_FOR_BASE_P}.
-
-@findex REGNO_OK_FOR_INDEX_P
-@item REGNO_OK_FOR_INDEX_P (@var{num})
+@code{REGNO_OK_FOR_BASE_P}. The mode may be @code{VOIDmode} for
+addresses that appear outside a @code{MEM}, i.e., as an
+@code{address_operand}.
+
+@end defmac
+
+@defmac REGNO_MODE_OK_FOR_REG_BASE_P (@var{num}, @var{mode})
+A C expression which is nonzero if register number @var{num} is suitable for
+use as a base register in base plus index operand addresses, accessing
+memory in mode @var{mode}. It may be either a suitable hard register or a
+pseudo register that has been allocated such a hard register. You should
+define this macro if base plus index addresses have different requirements
+than other base register uses.
+
+Use of this macro is deprecated; please use the more general
+@code{REGNO_MODE_CODE_OK_FOR_BASE_P}.
+@end defmac
+
+@defmac REGNO_MODE_CODE_OK_FOR_BASE_P (@var{num}, @var{mode}, @var{outer_code}, @var{index_code})
+A C expression that is just like @code{REGNO_MODE_OK_FOR_BASE_P}, except
+that that expression may examine the context in which the register
+appears in the memory reference. @var{outer_code} is the code of the
+immediately enclosing expression (@code{MEM} if at the top level of the
+address, @code{ADDRESS} for something that occurs in an
+@code{address_operand}). @var{index_code} is the code of the
+corresponding index expression if @var{outer_code} is @code{PLUS};
+@code{SCRATCH} otherwise. The mode may be @code{VOIDmode} for addresses
+that appear outside a @code{MEM}, i.e., as an @code{address_operand}.
+@end defmac
+
+@defmac REGNO_OK_FOR_INDEX_P (@var{num})
A C expression which is nonzero if register number @var{num} is
suitable for use as an index register in operand addresses. It may be
either a suitable hard register or a pseudo register that has been
may serve in each capacity. The compiler will try both labelings,
looking for one that is valid, and will reload one or both registers
only if neither labeling works.
+@end defmac
-@findex PREFERRED_RELOAD_CLASS
-@item PREFERRED_RELOAD_CLASS (@var{x}, @var{class})
+@defmac PREFERRED_RELOAD_CLASS (@var{x}, @var{class})
A C expression that places additional restrictions on the register class
to use when it is necessary to copy value @var{x} into a register in class
@var{class}. The value is a register class; perhaps @var{class}, or perhaps
another, smaller class. On many machines, the following definition is
safe:
-@example
+@smallexample
#define PREFERRED_RELOAD_CLASS(X,CLASS) CLASS
-@end example
+@end smallexample
Sometimes returning a more restrictive class makes better code. For
example, on the 68000, when @var{x} is an integer constant that is in range
@code{DATA_REGS} as long as @var{class} includes the data registers.
Requiring a data register guarantees that a @samp{moveq} will be used.
-If @var{x} is a @code{const_double}, by returning @code{NO_REGS}
-you can force @var{x} into a memory constant. This is useful on
-certain machines where immediate floating values cannot be loaded into
-certain kinds of registers.
-
-@findex PREFERRED_OUTPUT_RELOAD_CLASS
-@item PREFERRED_OUTPUT_RELOAD_CLASS (@var{x}, @var{class})
+One case where @code{PREFERRED_RELOAD_CLASS} must not return
+@var{class} is if @var{x} is a legitimate constant which cannot be
+loaded into some register class. By returning @code{NO_REGS} you can
+force @var{x} into a memory location. For example, rs6000 can load
+immediate values into general-purpose registers, but does not have an
+instruction for loading an immediate value into a floating-point
+register, so @code{PREFERRED_RELOAD_CLASS} returns @code{NO_REGS} when
+@var{x} is a floating-point constant. If the constant can't be loaded
+into any kind of register, code generation will be better if
+@code{LEGITIMATE_CONSTANT_P} makes the constant illegitimate instead
+of using @code{PREFERRED_RELOAD_CLASS}.
+
+If an insn has pseudos in it after register allocation, reload will go
+through the alternatives and call repeatedly @code{PREFERRED_RELOAD_CLASS}
+to find the best one. Returning @code{NO_REGS}, in this case, makes
+reload add a @code{!} in front of the constraint: the x86 back-end uses
+this feature to discourage usage of 387 registers when math is done in
+the SSE registers (and vice versa).
+@end defmac
+
+@defmac PREFERRED_OUTPUT_RELOAD_CLASS (@var{x}, @var{class})
Like @code{PREFERRED_RELOAD_CLASS}, but for output reloads instead of
input reloads. If you don't define this macro, the default is to use
@var{class}, unchanged.
-@findex LIMIT_RELOAD_CLASS
-@item LIMIT_RELOAD_CLASS (@var{mode}, @var{class})
+You can also use @code{PREFERRED_OUTPUT_RELOAD_CLASS} to discourage
+reload from using some alternatives, like @code{PREFERRED_RELOAD_CLASS}.
+@end defmac
+
+@defmac LIMIT_RELOAD_CLASS (@var{mode}, @var{class})
A C expression that places additional restrictions on the register class
to use when it is necessary to be able to hold a value of mode
@var{mode} in a reload register for which class @var{class} would
Don't define this macro unless the target machine has limitations which
require the macro to do something nontrivial.
+@end defmac
-@findex SECONDARY_RELOAD_CLASS
-@findex SECONDARY_INPUT_RELOAD_CLASS
-@findex SECONDARY_OUTPUT_RELOAD_CLASS
-@item SECONDARY_RELOAD_CLASS (@var{class}, @var{mode}, @var{x})
-@itemx SECONDARY_INPUT_RELOAD_CLASS (@var{class}, @var{mode}, @var{x})
-@itemx SECONDARY_OUTPUT_RELOAD_CLASS (@var{class}, @var{mode}, @var{x})
+@deftypefn {Target Hook} {enum reg_class} TARGET_SECONDARY_RELOAD (bool @var{in_p}, rtx @var{x}, enum reg_class @var{reload_class}, enum machine_mode @var{reload_mode}, secondary_reload_info *@var{sri})
Many machines have some registers that cannot be copied directly to or
from memory or even from other types of registers. An example is the
@samp{MQ} register, which on most machines, can only be copied to or
-from general registers, but not memory. Some machines allow copying all
-registers to and from memory, but require a scratch register for stores
-to some memory locations (e.g., those with symbolic address on the RT,
-and those with certain symbolic address on the Sparc when compiling
-PIC)@. In some cases, both an intermediate and a scratch register are
-required.
+from general registers, but not memory. Below, we shall be using the
+term 'intermediate register' when a move operation cannot be performed
+directly, but has to be done by copying the source into the intermediate
+register first, and then copying the intermediate register to the
+destination. An intermediate register always has the same mode as
+source and destination. Since it holds the actual value being copied,
+reload might apply optimizations to re-use an intermediate register
+and eliding the copy from the source when it can determine that the
+intermediate register still holds the required value.
+
+Another kind of secondary reload is required on some machines which
+allow copying all registers to and from memory, but require a scratch
+register for stores to some memory locations (e.g., those with symbolic
+address on the RT, and those with certain symbolic address on the SPARC
+when compiling PIC)@. Scratch registers need not have the same mode
+as the value being copied, and usually hold a different value that
+that being copied. Special patterns in the md file are needed to
+describe how the copy is performed with the help of the scratch register;
+these patterns also describe the number, register class(es) and mode(s)
+of the scratch register(s).
+
+In some cases, both an intermediate and a scratch register are required.
+
+For input reloads, this target hook is called with nonzero @var{in_p},
+and @var{x} is an rtx that needs to be copied to a register of class
+@var{reload_class} in @var{reload_mode}. For output reloads, this target
+hook is called with zero @var{in_p}, and a register of class @var{reload_class}
+needs to be copied to rtx @var{x} in @var{reload_mode}.
+
+If copying a register of @var{reload_class} from/to @var{x} requires
+an intermediate register, the hook @code{secondary_reload} should
+return the register class required for this intermediate register.
+If no intermediate register is required, it should return NO_REGS.
+If more than one intermediate register is required, describe the one
+that is closest in the copy chain to the reload register.
+
+If scratch registers are needed, you also have to describe how to
+perform the copy from/to the reload register to/from this
+closest intermediate register. Or if no intermediate register is
+required, but still a scratch register is needed, describe the
+copy from/to the reload register to/from the reload operand @var{x}.
+
+You do this by setting @code{sri->icode} to the instruction code of a pattern
+in the md file which performs the move. Operands 0 and 1 are the output
+and input of this copy, respectively. Operands from operand 2 onward are
+for scratch operands. These scratch operands must have a mode, and a
+single-register-class
+@c [later: or memory]
+output constraint.
+
+When an intermediate register is used, the @code{secondary_reload}
+hook will be called again to determine how to copy the intermediate
+register to/from the reload operand @var{x}, so your hook must also
+have code to handle the register class of the intermediate operand.
+
+@c [For later: maybe we'll allow multi-alternative reload patterns -
+@c the port maintainer could name a mov<mode> pattern that has clobbers -
+@c and match the constraints of input and output to determine the required
+@c alternative. A restriction would be that constraints used to match
+@c against reloads registers would have to be written as register class
+@c constraints, or we need a new target macro / hook that tells us if an
+@c arbitrary constraint can match an unknown register of a given class.
+@c Such a macro / hook would also be useful in other places.]
+
+
+@var{x} might be a pseudo-register or a @code{subreg} of a
+pseudo-register, which could either be in a hard register or in memory.
+Use @code{true_regnum} to find out; it will return @minus{}1 if the pseudo is
+in memory and the hard register number if it is in a register.
-You should define these macros to indicate to the reload phase that it may
+Scratch operands in memory (constraint @code{"=m"} / @code{"=&m"}) are
+currently not supported. For the time being, you will have to continue
+to use @code{SECONDARY_MEMORY_NEEDED} for that purpose.
+
+@code{copy_cost} also uses this target hook to find out how values are
+copied. If you want it to include some extra cost for the need to allocate
+(a) scratch register(s), set @code{sri->extra_cost} to the additional cost.
+Or if two dependent moves are supposed to have a lower cost than the sum
+of the individual moves due to expected fortuitous scheduling and/or special
+forwarding logic, you can set @code{sri->extra_cost} to a negative amount.
+@end deftypefn
+
+@defmac SECONDARY_RELOAD_CLASS (@var{class}, @var{mode}, @var{x})
+@defmacx SECONDARY_INPUT_RELOAD_CLASS (@var{class}, @var{mode}, @var{x})
+@defmacx SECONDARY_OUTPUT_RELOAD_CLASS (@var{class}, @var{mode}, @var{x})
+These macros are obsolete, new ports should use the target hook
+@code{TARGET_SECONDARY_RELOAD} instead.
+
+These are obsolete macros, replaced by the @code{TARGET_SECONDARY_RELOAD}
+target hook. Older ports still define these macros to indicate to the
+reload phase that it may
need to allocate at least one register for a reload in addition to the
register to contain the data. Specifically, if copying @var{x} to a
register @var{class} in @var{mode} requires an intermediate register,
-you should define @code{SECONDARY_INPUT_RELOAD_CLASS} to return the
+you were supposed to define @code{SECONDARY_INPUT_RELOAD_CLASS} to return the
largest register class all of whose registers can be used as
intermediate registers or scratch registers.
If copying a register @var{class} in @var{mode} to @var{x} requires an
intermediate or scratch register, @code{SECONDARY_OUTPUT_RELOAD_CLASS}
-should be defined to return the largest register class required. If the
-requirements for input and output reloads are the same, the macro
-@code{SECONDARY_RELOAD_CLASS} should be used instead of defining both
+was supposed to be defined be defined to return the largest register
+class required. If the
+requirements for input and output reloads were the same, the macro
+@code{SECONDARY_RELOAD_CLASS} should have been used instead of defining both
macros identically.
The values returned by these macros are often @code{GENERAL_REGS}.
macro if it would always return @code{NO_REGS}.
If a scratch register is required (either with or without an
-intermediate register), you should define patterns for
+intermediate register), you were supposed to define patterns for
@samp{reload_in@var{m}} or @samp{reload_out@var{m}}, as required
-(@pxref{Standard Names}. These patterns, which will normally be
+(@pxref{Standard Names}. These patterns, which were normally
implemented with a @code{define_expand}, should be similar to the
@samp{mov@var{m}} patterns, except that operand 2 is the scratch
register.
-Define constraints for the reload register and scratch register that
+These patterns need constraints for the reload register and scratch
+register that
contain a single register class. If the original reload register (whose
class is @var{class}) can meet the constraint given in the pattern, the
value returned by these macros is used for the class of the scratch
the copy and the @code{mov@var{m}} pattern should use memory as an
intermediate storage. This case often occurs between floating-point and
general registers.
+@end defmac
-@findex SECONDARY_MEMORY_NEEDED
-@item SECONDARY_MEMORY_NEEDED (@var{class1}, @var{class2}, @var{m})
+@defmac SECONDARY_MEMORY_NEEDED (@var{class1}, @var{class2}, @var{m})
Certain machines have the property that some registers cannot be copied
to some other registers without using memory. Define this macro on
those machines to be a C expression that is nonzero if objects of mode
and loading that memory location into a register of @var{class2}.
Do not define this macro if its value would always be zero.
+@end defmac
-@findex SECONDARY_MEMORY_NEEDED_RTX
-@item SECONDARY_MEMORY_NEEDED_RTX (@var{mode})
+@defmac SECONDARY_MEMORY_NEEDED_RTX (@var{mode})
Normally when @code{SECONDARY_MEMORY_NEEDED} is defined, the compiler
allocates a stack slot for a memory location needed for register copies.
If this macro is defined, the compiler instead uses the memory location
Do not define this macro if you do not define
@code{SECONDARY_MEMORY_NEEDED}.
+@end defmac
-@findex SECONDARY_MEMORY_NEEDED_MODE
-@item SECONDARY_MEMORY_NEEDED_MODE (@var{mode})
+@defmac SECONDARY_MEMORY_NEEDED_MODE (@var{mode})
When the compiler needs a secondary memory location to copy between two
registers of mode @var{mode}, it normally allocates sufficient memory to
hold a quantity of @code{BITS_PER_WORD} bits and performs the store and
Do not define this macro if you do not define
@code{SECONDARY_MEMORY_NEEDED} or if widening @var{mode} to a mode that
is @code{BITS_PER_WORD} bits wide is correct for your machine.
+@end defmac
-@findex SMALL_REGISTER_CLASSES
-@item SMALL_REGISTER_CLASSES
+@defmac SMALL_REGISTER_CLASSES
On some machines, it is risky to let hard registers live across arbitrary
insns. Typically, these machines have instructions that require values
to be in specific registers (like an accumulator), and reload will fail
with a nonzero value when it is required, the compiler will run out of
spill registers and print a fatal error message. For most machines, you
should not define this macro at all.
+@end defmac
-@findex CLASS_LIKELY_SPILLED_P
-@item CLASS_LIKELY_SPILLED_P (@var{class})
+@defmac CLASS_LIKELY_SPILLED_P (@var{class})
A C expression whose value is nonzero if pseudos that have been assigned
to registers of class @var{class} would likely be spilled because
registers of @var{class} are needed for spill registers.
reallocation, you should not change the definition of this macro since
the only effect of such a definition would be to slow down register
allocation.
+@end defmac
-@findex CLASS_MAX_NREGS
-@item CLASS_MAX_NREGS (@var{class}, @var{mode})
+@defmac CLASS_MAX_NREGS (@var{class}, @var{mode})
A C expression for the maximum number of consecutive registers
of class @var{class} needed to hold a value of mode @var{mode}.
This macro helps control the handling of multiple-word values
in the reload pass.
+@end defmac
-@item CLASS_CANNOT_CHANGE_MODE
-If defined, a C expression for a class that contains registers for
-which the compiler may not change modes arbitrarily.
-
-@item CLASS_CANNOT_CHANGE_MODE_P(@var{from}, @var{to})
-A C expression that is true if, for a register in
-@code{CLASS_CANNOT_CHANGE_MODE}, the requested mode punning is invalid.
+@defmac CANNOT_CHANGE_MODE_CLASS (@var{from}, @var{to}, @var{class})
+If defined, a C expression that returns nonzero for a @var{class} for which
+a change from mode @var{from} to mode @var{to} is invalid.
For the example, loading 32-bit integer or floating-point objects into
floating-point registers on the Alpha extends them to 64 bits.
Therefore loading a 64-bit object and then storing it as a 32-bit object
does not store the low-order 32 bits, as would be the case for a normal
-register. Therefore, @file{alpha.h} defines @code{CLASS_CANNOT_CHANGE_MODE}
-as @code{FLOAT_REGS} and @code{CLASS_CANNOT_CHANGE_MODE_P} restricts
-mode changes to same-size modes.
+register. Therefore, @file{alpha.h} defines @code{CANNOT_CHANGE_MODE_CLASS}
+as below:
-Compare this to IA-64, which extends floating-point values to 82 bits,
-and stores 64-bit integers in a different format than 64-bit doubles.
-Therefore @code{CLASS_CANNOT_CHANGE_MODE_P} is always true.
-@end table
+@smallexample
+#define CANNOT_CHANGE_MODE_CLASS(FROM, TO, CLASS) \
+ (GET_MODE_SIZE (FROM) != GET_MODE_SIZE (TO) \
+ ? reg_classes_intersect_p (FLOAT_REGS, (CLASS)) : 0)
+@end smallexample
+@end defmac
+
+@deftypefn {Target Hook} {const enum reg_class *} TARGET_IRA_COVER_CLASSES ()
+Return an array of cover classes for the Integrated Register Allocator
+(@acronym{IRA}). Cover classes are a set of non-intersecting register
+classes covering all hard registers used for register allocation
+purposes. If a move between two registers in the same cover class is
+possible, it should be cheaper than a load or store of the registers.
+The array is terminated by a @code{LIM_REG_CLASSES} element.
+
+This hook is called once at compiler startup, after the command-line
+options have been processed. It is then re-examined by every call to
+@code{target_reinit}.
+
+The default implementation returns @code{IRA_COVER_CLASSES}, if defined,
+otherwise there is no default implementation. You must define either this
+macro or @code{IRA_COVER_CLASSES} in order to use the integrated register
+allocator with Chaitin-Briggs coloring. If the macro is not defined,
+the only available coloring algorithm is Chow's priority coloring.
+@end deftypefn
+
+@defmac IRA_COVER_CLASSES
+See the documentation for @code{TARGET_IRA_COVER_CLASSES}.
+@end defmac
+
+@node Old Constraints
+@section Obsolete Macros for Defining Constraints
+@cindex defining constraints, obsolete method
+@cindex constraints, defining, obsolete method
+
+Machine-specific constraints can be defined with these macros instead
+of the machine description constructs described in @ref{Define
+Constraints}. This mechanism is obsolete. New ports should not use
+it; old ports should convert to the new mechanism.
+
+@defmac CONSTRAINT_LEN (@var{char}, @var{str})
+For the constraint at the start of @var{str}, which starts with the letter
+@var{c}, return the length. This allows you to have register class /
+constant / extra constraints that are longer than a single letter;
+you don't need to define this macro if you can do with single-letter
+constraints only. The definition of this macro should use
+DEFAULT_CONSTRAINT_LEN for all the characters that you don't want
+to handle specially.
+There are some sanity checks in genoutput.c that check the constraint lengths
+for the md file, so you can also use this macro to help you while you are
+transitioning from a byzantine single-letter-constraint scheme: when you
+return a negative length for a constraint you want to re-use, genoutput
+will complain about every instance where it is used in the md file.
+@end defmac
+
+@defmac REG_CLASS_FROM_LETTER (@var{char})
+A C expression which defines the machine-dependent operand constraint
+letters for register classes. If @var{char} is such a letter, the
+value should be the register class corresponding to it. Otherwise,
+the value should be @code{NO_REGS}. The register letter @samp{r},
+corresponding to class @code{GENERAL_REGS}, will not be passed
+to this macro; you do not need to handle it.
+@end defmac
-Three other special macros describe which operands fit which constraint
-letters.
+@defmac REG_CLASS_FROM_CONSTRAINT (@var{char}, @var{str})
+Like @code{REG_CLASS_FROM_LETTER}, but you also get the constraint string
+passed in @var{str}, so that you can use suffixes to distinguish between
+different variants.
+@end defmac
-@table @code
-@findex CONST_OK_FOR_LETTER_P
-@item CONST_OK_FOR_LETTER_P (@var{value}, @var{c})
+@defmac CONST_OK_FOR_LETTER_P (@var{value}, @var{c})
A C expression that defines the machine-dependent operand constraint
letters (@samp{I}, @samp{J}, @samp{K}, @dots{} @samp{P}) that specify
particular ranges of integer values. If @var{c} is one of those
the appropriate range and return 1 if so, 0 otherwise. If @var{c} is
not one of those letters, the value should be 0 regardless of
@var{value}.
+@end defmac
-@findex CONST_DOUBLE_OK_FOR_LETTER_P
-@item CONST_DOUBLE_OK_FOR_LETTER_P (@var{value}, @var{c})
+@defmac CONST_OK_FOR_CONSTRAINT_P (@var{value}, @var{c}, @var{str})
+Like @code{CONST_OK_FOR_LETTER_P}, but you also get the constraint
+string passed in @var{str}, so that you can use suffixes to distinguish
+between different variants.
+@end defmac
+
+@defmac CONST_DOUBLE_OK_FOR_LETTER_P (@var{value}, @var{c})
A C expression that defines the machine-dependent operand constraint
letters that specify particular ranges of @code{const_double} values
(@samp{G} or @samp{H}).
@code{DImode} fixed-point constants. A given letter can accept either
or both kinds of values. It can use @code{GET_MODE} to distinguish
between these kinds.
+@end defmac
+
+@defmac CONST_DOUBLE_OK_FOR_CONSTRAINT_P (@var{value}, @var{c}, @var{str})
+Like @code{CONST_DOUBLE_OK_FOR_LETTER_P}, but you also get the constraint
+string passed in @var{str}, so that you can use suffixes to distinguish
+between different variants.
+@end defmac
-@findex EXTRA_CONSTRAINT
-@item EXTRA_CONSTRAINT (@var{value}, @var{c})
+@defmac EXTRA_CONSTRAINT (@var{value}, @var{c})
A C expression that defines the optional machine-dependent constraint
letters that can be used to segregate specific types of operands, usually
memory references, for the target machine. Any letter that is not
-elsewhere defined and not matched by @code{REG_CLASS_FROM_LETTER}
+elsewhere defined and not matched by @code{REG_CLASS_FROM_LETTER} /
+@code{REG_CLASS_FROM_CONSTRAINT}
may be used. Normally this macro will not be defined.
If it is required for a particular target machine, it should return 1
a @samp{Q} constraint on the input and @samp{r} on the output. The next
alternative specifies @samp{m} on the input and a register class that
does not include r0 on the output.
-@end table
+@end defmac
+
+@defmac EXTRA_CONSTRAINT_STR (@var{value}, @var{c}, @var{str})
+Like @code{EXTRA_CONSTRAINT}, but you also get the constraint string passed
+in @var{str}, so that you can use suffixes to distinguish between different
+variants.
+@end defmac
+
+@defmac EXTRA_MEMORY_CONSTRAINT (@var{c}, @var{str})
+A C expression that defines the optional machine-dependent constraint
+letters, amongst those accepted by @code{EXTRA_CONSTRAINT}, that should
+be treated like memory constraints by the reload pass.
+
+It should return 1 if the operand type represented by the constraint
+at the start of @var{str}, the first letter of which is the letter @var{c},
+comprises a subset of all memory references including
+all those whose address is simply a base register. This allows the reload
+pass to reload an operand, if it does not directly correspond to the operand
+type of @var{c}, by copying its address into a base register.
+
+For example, on the S/390, some instructions do not accept arbitrary
+memory references, but only those that do not make use of an index
+register. The constraint letter @samp{Q} is defined via
+@code{EXTRA_CONSTRAINT} as representing a memory address of this type.
+If the letter @samp{Q} is marked as @code{EXTRA_MEMORY_CONSTRAINT},
+a @samp{Q} constraint can handle any memory operand, because the
+reload pass knows it can be reloaded by copying the memory address
+into a base register if required. This is analogous to the way
+a @samp{o} constraint can handle any memory operand.
+@end defmac
+
+@defmac EXTRA_ADDRESS_CONSTRAINT (@var{c}, @var{str})
+A C expression that defines the optional machine-dependent constraint
+letters, amongst those accepted by @code{EXTRA_CONSTRAINT} /
+@code{EXTRA_CONSTRAINT_STR}, that should
+be treated like address constraints by the reload pass.
+
+It should return 1 if the operand type represented by the constraint
+at the start of @var{str}, which starts with the letter @var{c}, comprises
+a subset of all memory addresses including
+all those that consist of just a base register. This allows the reload
+pass to reload an operand, if it does not directly correspond to the operand
+type of @var{str}, by copying it into a base register.
+
+Any constraint marked as @code{EXTRA_ADDRESS_CONSTRAINT} can only
+be used with the @code{address_operand} predicate. It is treated
+analogously to the @samp{p} constraint.
+@end defmac
@node Stack and Calling
@section Stack Layout and Calling Conventions
* Function Entry::
* Profiling::
* Tail Calls::
+* Stack Smashing Protection::
@end menu
@node Frame Layout
@c prevent bad page break with this line
Here is the basic stack layout.
-@table @code
-@findex STACK_GROWS_DOWNWARD
-@item STACK_GROWS_DOWNWARD
+@defmac STACK_GROWS_DOWNWARD
Define this macro if pushing a word onto the stack moves the stack
pointer to a smaller address.
-When we say, ``define this macro if @dots{},'' it means that the
+When we say, ``define this macro if @dots{}'', it means that the
compiler checks this macro only with @code{#ifdef} so the precise
definition used does not matter.
+@end defmac
-@findex STACK_PUSH_CODE
-@item STACK_PUSH_CODE
-
+@defmac STACK_PUSH_CODE
This macro defines the operation used when something is pushed
on the stack. In RTL, a push operation will be
-@code{(set (mem (STACK_PUSH_CODE (reg sp))) ...)}
+@code{(set (mem (STACK_PUSH_CODE (reg sp))) @dots{})}
The choices are @code{PRE_DEC}, @code{POST_DEC}, @code{PRE_INC},
and @code{POST_INC}. Which of these is correct depends on
The default is @code{PRE_DEC} when @code{STACK_GROWS_DOWNWARD} is
defined, which is almost always right, and @code{PRE_INC} otherwise,
which is often wrong.
+@end defmac
-@findex FRAME_GROWS_DOWNWARD
-@item FRAME_GROWS_DOWNWARD
-Define this macro if the addresses of local variable slots are at negative
-offsets from the frame pointer.
+@defmac FRAME_GROWS_DOWNWARD
+Define this macro to nonzero value if the addresses of local variable slots
+are at negative offsets from the frame pointer.
+@end defmac
-@findex ARGS_GROW_DOWNWARD
-@item ARGS_GROW_DOWNWARD
+@defmac ARGS_GROW_DOWNWARD
Define this macro if successive arguments to a function occupy decreasing
addresses on the stack.
+@end defmac
-@findex STARTING_FRAME_OFFSET
-@item STARTING_FRAME_OFFSET
+@defmac STARTING_FRAME_OFFSET
Offset from the frame pointer to the first local variable slot to be allocated.
If @code{FRAME_GROWS_DOWNWARD}, find the next slot's offset by
value @code{STARTING_FRAME_OFFSET}.
@c i'm not sure if the above is still correct.. had to change it to get
@c rid of an overfull. --mew 2feb93
+@end defmac
-@findex STACK_POINTER_OFFSET
-@item STACK_POINTER_OFFSET
+@defmac STACK_ALIGNMENT_NEEDED
+Define to zero to disable final alignment of the stack during reload.
+The nonzero default for this macro is suitable for most ports.
+
+On ports where @code{STARTING_FRAME_OFFSET} is nonzero or where there
+is a register save block following the local block that doesn't require
+alignment to @code{STACK_BOUNDARY}, it may be beneficial to disable
+stack alignment and do it in the backend.
+@end defmac
+
+@defmac STACK_POINTER_OFFSET
Offset from the stack pointer register to the first location at which
outgoing arguments are placed. If not specified, the default value of
zero is used. This is the proper value for most machines.
If @code{ARGS_GROW_DOWNWARD}, this is the offset to the location above
the first location at which outgoing arguments are placed.
+@end defmac
-@findex FIRST_PARM_OFFSET
-@item FIRST_PARM_OFFSET (@var{fundecl})
+@defmac FIRST_PARM_OFFSET (@var{fundecl})
Offset from the argument pointer register to the first argument's
address. On some machines it may depend on the data type of the
function.
If @code{ARGS_GROW_DOWNWARD}, this is the offset to the location above
the first argument's address.
+@end defmac
-@findex STACK_DYNAMIC_OFFSET
-@item STACK_DYNAMIC_OFFSET (@var{fundecl})
+@defmac STACK_DYNAMIC_OFFSET (@var{fundecl})
Offset from the stack pointer register to an item dynamically allocated
on the stack, e.g., by @code{alloca}.
The default value for this macro is @code{STACK_POINTER_OFFSET} plus the
length of the outgoing arguments. The default is correct for most
machines. See @file{function.c} for details.
-
-@findex DYNAMIC_CHAIN_ADDRESS
-@item DYNAMIC_CHAIN_ADDRESS (@var{frameaddr})
+@end defmac
+
+@defmac INITIAL_FRAME_ADDRESS_RTX
+A C expression whose value is RTL representing the address of the initial
+stack frame. This address is passed to @code{RETURN_ADDR_RTX} and
+@code{DYNAMIC_CHAIN_ADDRESS}. If you don't define this macro, a reasonable
+default value will be used. Define this macro in order to make frame pointer
+elimination work in the presence of @code{__builtin_frame_address (count)} and
+@code{__builtin_return_address (count)} for @code{count} not equal to zero.
+@end defmac
+
+@defmac DYNAMIC_CHAIN_ADDRESS (@var{frameaddr})
A C expression whose value is RTL representing the address in a stack
frame where the pointer to the caller's frame is stored. Assume that
@var{frameaddr} is an RTL expression for the address of the stack frame
If you don't define this macro, the default is to return the value
of @var{frameaddr}---that is, the stack frame address is also the
address of the stack word that points to the previous frame.
+@end defmac
-@findex SETUP_FRAME_ADDRESSES
-@item SETUP_FRAME_ADDRESSES
+@defmac SETUP_FRAME_ADDRESSES
If defined, a C expression that produces the machine-specific code to
setup the stack so that arbitrary frames can be accessed. For example,
-on the Sparc, we must flush all of the register windows to the stack
+on the SPARC, we must flush all of the register windows to the stack
before we can access arbitrary stack frames. You will seldom need to
define this macro.
+@end defmac
-@findex BUILTIN_SETJMP_FRAME_VALUE
-@item BUILTIN_SETJMP_FRAME_VALUE
-If defined, a C expression that contains an rtx that is used to store
+@deftypefn {Target Hook} bool TARGET_BUILTIN_SETJMP_FRAME_VALUE ()
+This target hook should return an rtx that is used to store
the address of the current frame into the built in @code{setjmp} buffer.
The default value, @code{virtual_stack_vars_rtx}, is correct for most
-machines. One reason you may need to define this macro is if
+machines. One reason you may need to define this target hook is if
@code{hard_frame_pointer_rtx} is the appropriate value on your machine.
+@end deftypefn
-@findex RETURN_ADDR_RTX
-@item RETURN_ADDR_RTX (@var{count}, @var{frameaddr})
+@defmac FRAME_ADDR_RTX (@var{frameaddr})
+A C expression whose value is RTL representing the value of the frame
+address for the current frame. @var{frameaddr} is the frame pointer
+of the current frame. This is used for __builtin_frame_address.
+You need only define this macro if the frame address is not the same
+as the frame pointer. Most machines do not need to define it.
+@end defmac
+
+@defmac RETURN_ADDR_RTX (@var{count}, @var{frameaddr})
A C expression whose value is RTL representing the value of the return
address for the frame @var{count} steps up from the current frame, after
the prologue. @var{frameaddr} is the frame pointer of the @var{count}
@code{RETURN_ADDR_IN_PREVIOUS_FRAME} is defined.
The value of the expression must always be the correct address when
-@var{count} is zero, but may be @code{NULL_RTX} if there is not way to
+@var{count} is zero, but may be @code{NULL_RTX} if there is no way to
determine the return address of other frames.
+@end defmac
-@findex RETURN_ADDR_IN_PREVIOUS_FRAME
-@item RETURN_ADDR_IN_PREVIOUS_FRAME
+@defmac RETURN_ADDR_IN_PREVIOUS_FRAME
Define this if the return address of a particular stack frame is accessed
from the frame pointer of the previous stack frame.
+@end defmac
-@findex INCOMING_RETURN_ADDR_RTX
-@item INCOMING_RETURN_ADDR_RTX
+@defmac INCOMING_RETURN_ADDR_RTX
A C expression whose value is RTL representing the location of the
incoming return address at the beginning of any function, before the
prologue. This RTL is either a @code{REG}, indicating that the return
If this RTL is a @code{REG}, you should also define
@code{DWARF_FRAME_RETURN_COLUMN} to @code{DWARF_FRAME_REGNUM (REGNO)}.
+@end defmac
+
+@defmac DWARF_ALT_FRAME_RETURN_COLUMN
+A C expression whose value is an integer giving a DWARF 2 column
+number that may be used as an alternative return column. The column
+must not correspond to any gcc hard register (that is, it must not
+be in the range of @code{DWARF_FRAME_REGNUM}).
+
+This macro can be useful if @code{DWARF_FRAME_RETURN_COLUMN} is set to a
+general register, but an alternative column needs to be used for signal
+frames. Some targets have also used different frame return columns
+over time.
+@end defmac
+
+@defmac DWARF_ZERO_REG
+A C expression whose value is an integer giving a DWARF 2 register
+number that is considered to always have the value zero. This should
+only be defined if the target has an architected zero register, and
+someone decided it was a good idea to use that register number to
+terminate the stack backtrace. New ports should avoid this.
+@end defmac
+
+@deftypefn {Target Hook} void TARGET_DWARF_HANDLE_FRAME_UNSPEC (const char *@var{label}, rtx @var{pattern}, int @var{index})
+This target hook allows the backend to emit frame-related insns that
+contain UNSPECs or UNSPEC_VOLATILEs. The DWARF 2 call frame debugging
+info engine will invoke it on insns of the form
+@smallexample
+(set (reg) (unspec [@dots{}] UNSPEC_INDEX))
+@end smallexample
+and
+@smallexample
+(set (reg) (unspec_volatile [@dots{}] UNSPECV_INDEX)).
+@end smallexample
+to let the backend emit the call frame instructions. @var{label} is
+the CFI label attached to the insn, @var{pattern} is the pattern of
+the insn and @var{index} is @code{UNSPEC_INDEX} or @code{UNSPECV_INDEX}.
+@end deftypefn
-@findex INCOMING_FRAME_SP_OFFSET
-@item INCOMING_FRAME_SP_OFFSET
+@defmac INCOMING_FRAME_SP_OFFSET
A C expression whose value is an integer giving the offset, in bytes,
from the value of the stack pointer register to the top of the stack
frame at the beginning of any function, before the prologue. The top of
You only need to define this macro if you want to support call frame
debugging information like that provided by DWARF 2.
+@end defmac
-@findex ARG_POINTER_CFA_OFFSET
-@item ARG_POINTER_CFA_OFFSET (@var{fundecl})
+@defmac ARG_POINTER_CFA_OFFSET (@var{fundecl})
A C expression whose value is an integer giving the offset, in bytes,
from the argument pointer to the canonical frame address (cfa). The
final value should coincide with that calculated by
You only need to define this macro if the default is incorrect, and you
want to support call frame debugging information like that provided by
DWARF 2.
-
-@findex SMALL_STACK
-@item SMALL_STACK
-Define this macro if the stack size for the target is very small. This
-has the effect of disabling gcc's built-in @samp{alloca}, though
-@samp{__builtin_alloca} is not affected.
-@end table
+@end defmac
+
+@defmac FRAME_POINTER_CFA_OFFSET (@var{fundecl})
+If defined, a C expression whose value is an integer giving the offset
+in bytes from the frame pointer to the canonical frame address (cfa).
+The final value should coincide with that calculated by
+@code{INCOMING_FRAME_SP_OFFSET}.
+
+Normally the CFA is calculated as an offset from the argument pointer,
+via @code{ARG_POINTER_CFA_OFFSET}, but if the argument pointer is
+variable due to the ABI, this may not be possible. If this macro is
+defined, it implies that the virtual register instantiation should be
+based on the frame pointer instead of the argument pointer. Only one
+of @code{FRAME_POINTER_CFA_OFFSET} and @code{ARG_POINTER_CFA_OFFSET}
+should be defined.
+@end defmac
+
+@defmac CFA_FRAME_BASE_OFFSET (@var{fundecl})
+If defined, a C expression whose value is an integer giving the offset
+in bytes from the canonical frame address (cfa) to the frame base used
+in DWARF 2 debug information. The default is zero. A different value
+may reduce the size of debug information on some ports.
+@end defmac
@node Exception Handling
@subsection Exception Handling Support
@cindex exception handling
-@table @code
-@findex EH_RETURN_DATA_REGNO
-@item EH_RETURN_DATA_REGNO (@var{N})
+@defmac EH_RETURN_DATA_REGNO (@var{N})
A C expression whose value is the @var{N}th register number used for
data by exception handlers, or @code{INVALID_REGNUM} if fewer than
@var{N} registers are usable.
You must define this macro if you want to support call frame exception
handling like that provided by DWARF 2.
+@end defmac
-@findex EH_RETURN_STACKADJ_RTX
-@item EH_RETURN_STACKADJ_RTX
+@defmac EH_RETURN_STACKADJ_RTX
A C expression whose value is RTL representing a location in which
to store a stack adjustment to be applied before function return.
This is used to unwind the stack to an exception handler's call frame.
Typically this is a call-clobbered hard register that is otherwise
untouched by the epilogue, but could also be a stack slot.
-You must define this macro if you want to support call frame exception
-handling like that provided by DWARF 2.
+Do not define this macro if the stack pointer is saved and restored
+by the regular prolog and epilog code in the call frame itself; in
+this case, the exception handling library routines will update the
+stack location to be restored in place. Otherwise, you must define
+this macro if you want to support call frame exception handling like
+that provided by DWARF 2.
+@end defmac
-@findex EH_RETURN_HANDLER_RTX
-@item EH_RETURN_HANDLER_RTX
+@defmac EH_RETURN_HANDLER_RTX
A C expression whose value is RTL representing a location in which
to store the address of an exception handler to which we should
return. It will not be assigned on code paths that return normally.
return address is stored. For targets that return by popping an
address off the stack, this might be a memory address just below
the @emph{target} call frame rather than inside the current call
-frame. @code{EH_RETURN_STACKADJ_RTX} will have already been assigned,
-so it may be used to calculate the location of the target call frame.
+frame. If defined, @code{EH_RETURN_STACKADJ_RTX} will have already
+been assigned, so it may be used to calculate the location of the
+target call frame.
Some targets have more complex requirements than storing to an
address calculable during initial code generation. In that case
If you want to support call frame exception handling, you must
define either this macro or the @code{eh_return} instruction pattern.
+@end defmac
-@findex ASM_PREFERRED_EH_DATA_FORMAT
-@item ASM_PREFERRED_EH_DATA_FORMAT(@var{code}, @var{global})
+@defmac RETURN_ADDR_OFFSET
+If defined, an integer-valued C expression for which rtl will be generated
+to add it to the exception handler address before it is searched in the
+exception handling tables, and to subtract it again from the address before
+using it to return to the exception handler.
+@end defmac
+
+@defmac ASM_PREFERRED_EH_DATA_FORMAT (@var{code}, @var{global})
This macro chooses the encoding of pointers embedded in the exception
handling sections. If at all possible, this should be defined such
that the exception handling section will not require dynamic relocations,
If this macro is not defined, pointers will not be encoded but
represented directly.
+@end defmac
-@findex ASM_MAYBE_OUTPUT_ENCODED_ADDR_RTX
-@item ASM_MAYBE_OUTPUT_ENCODED_ADDR_RTX(@var{file}, @var{encoding}, @var{size}, @var{addr}, @var{done})
+@defmac ASM_MAYBE_OUTPUT_ENCODED_ADDR_RTX (@var{file}, @var{encoding}, @var{size}, @var{addr}, @var{done})
This macro allows the target to emit whatever special magic is required
to represent the encoding chosen by @code{ASM_PREFERRED_EH_DATA_FORMAT}.
Generic code takes care of pc-relative and indirect encodings; this must
handled. @var{encoding} is the format chosen, @var{size} is the number
of bytes that the format occupies, @var{addr} is the @code{SYMBOL_REF}
to be emitted.
+@end defmac
+
+@defmac MD_UNWIND_SUPPORT
+A string specifying a file to be #include'd in unwind-dw2.c. The file
+so included typically defines @code{MD_FALLBACK_FRAME_STATE_FOR}.
+@end defmac
-@findex MD_FALLBACK_FRAME_STATE_FOR
-@item MD_FALLBACK_FRAME_STATE_FOR(@var{context}, @var{fs}, @var{success})
-This macro allows the target to add cpu and operating system specific
+@defmac MD_FALLBACK_FRAME_STATE_FOR (@var{context}, @var{fs})
+This macro allows the target to add CPU and operating system specific
code to the call-frame unwinder for use when there is no unwind data
available. The most common reason to implement this macro is to unwind
through signal frames.
-This macro is called from @code{uw_frame_state_for} in @file{unwind-dw2.c}
-and @file{unwind-ia64.c}. @var{context} is an @code{_Unwind_Context};
+This macro is called from @code{uw_frame_state_for} in
+@file{unwind-dw2.c}, @file{unwind-dw2-xtensa.c} and
+@file{unwind-ia64.c}. @var{context} is an @code{_Unwind_Context};
@var{fs} is an @code{_Unwind_FrameState}. Examine @code{context->ra}
for the address of the code being executed and @code{context->cfa} for
-the stack pointer value. If the frame can be decoded, the register save
-addresses should be updated in @var{fs} and the macro should branch to
-@var{success}. If the frame cannot be decoded, the macro should do
-nothing.
-@end table
+the stack pointer value. If the frame can be decoded, the register
+save addresses should be updated in @var{fs} and the macro should
+evaluate to @code{_URC_NO_REASON}. If the frame cannot be decoded,
+the macro should evaluate to @code{_URC_END_OF_STACK}.
+
+For proper signal handling in Java this macro is accompanied by
+@code{MAKE_THROW_FRAME}, defined in @file{libjava/include/*-signal.h} headers.
+@end defmac
+
+@defmac MD_HANDLE_UNWABI (@var{context}, @var{fs})
+This macro allows the target to add operating system specific code to the
+call-frame unwinder to handle the IA-64 @code{.unwabi} unwinding directive,
+usually used for signal or interrupt frames.
+
+This macro is called from @code{uw_update_context} in @file{unwind-ia64.c}.
+@var{context} is an @code{_Unwind_Context};
+@var{fs} is an @code{_Unwind_FrameState}. Examine @code{fs->unwabi}
+for the abi and context in the @code{.unwabi} directive. If the
+@code{.unwabi} directive can be handled, the register save addresses should
+be updated in @var{fs}.
+@end defmac
+
+@defmac TARGET_USES_WEAK_UNWIND_INFO
+A C expression that evaluates to true if the target requires unwind
+info to be given comdat linkage. Define it to be @code{1} if comdat
+linkage is necessary. The default is @code{0}.
+@end defmac
@node Stack Checking
@subsection Specifying How Stack Checking is Done
-GCC will check that stack references are within the boundaries of
-the stack, if the @option{-fstack-check} is specified, in one of three ways:
+GCC will check that stack references are within the boundaries of the
+stack, if the option @option{-fstack-check} is specified, in one of
+three ways:
@enumerate
@item
If the value of the @code{STACK_CHECK_BUILTIN} macro is nonzero, GCC
-will assume that you have arranged for stack checking to be done at
-appropriate places in the configuration files, e.g., in
-@code{TARGET_ASM_FUNCTION_PROLOGUE}. GCC will do not other special
-processing.
+will assume that you have arranged for full stack checking to be done
+at appropriate places in the configuration files. GCC will not do
+other special processing.
@item
-If @code{STACK_CHECK_BUILTIN} is zero and you defined a named pattern
-called @code{check_stack} in your @file{md} file, GCC will call that
-pattern with one argument which is the address to compare the stack
-value against. You must arrange for this pattern to report an error if
-the stack pointer is out of range.
+If @code{STACK_CHECK_BUILTIN} is zero and the value of the
+@code{STACK_CHECK_STATIC_BUILTIN} macro is nonzero, GCC will assume
+that you have arranged for static stack checking (checking of the
+static stack frame of functions) to be done at appropriate places
+in the configuration files. GCC will only emit code to do dynamic
+stack checking (checking on dynamic stack allocations) using the third
+approach below.
@item
If neither of the above are true, GCC will generate code to periodically
``probe'' the stack pointer using the values of the macros defined below.
@end enumerate
-Normally, you will use the default values of these macros, so GCC
-will use the third approach.
+If neither STACK_CHECK_BUILTIN nor STACK_CHECK_STATIC_BUILTIN is defined,
+GCC will change its allocation strategy for large objects if the option
+@option{-fstack-check} is specified: they will always be allocated
+dynamically if their size exceeds @code{STACK_CHECK_MAX_VAR_SIZE} bytes.
-@table @code
-@findex STACK_CHECK_BUILTIN
-@item STACK_CHECK_BUILTIN
+@defmac STACK_CHECK_BUILTIN
A nonzero value if stack checking is done by the configuration files in a
machine-dependent manner. You should define this macro if stack checking
-is require by the ABI of your machine or if you would like to have to stack
-checking in some more efficient way than GCC's portable approach.
-The default value of this macro is zero.
-
-@findex STACK_CHECK_PROBE_INTERVAL
-@item STACK_CHECK_PROBE_INTERVAL
+is require by the ABI of your machine or if you would like to do stack
+checking in some more efficient way than the generic approach. The default
+value of this macro is zero.
+@end defmac
+
+@defmac STACK_CHECK_STATIC_BUILTIN
+A nonzero value if static stack checking is done by the configuration files
+in a machine-dependent manner. You should define this macro if you would
+like to do static stack checking in some more efficient way than the generic
+approach. The default value of this macro is zero.
+@end defmac
+
+@defmac STACK_CHECK_PROBE_INTERVAL
An integer representing the interval at which GCC must generate stack
probe instructions. You will normally define this macro to be no larger
than the size of the ``guard pages'' at the end of a stack area. The
default value of 4096 is suitable for most systems.
+@end defmac
-@findex STACK_CHECK_PROBE_LOAD
-@item STACK_CHECK_PROBE_LOAD
-A integer which is nonzero if GCC should perform the stack probe
+@defmac STACK_CHECK_PROBE_LOAD
+An integer which is nonzero if GCC should perform the stack probe
as a load instruction and zero if GCC should use a store instruction.
The default is zero, which is the most efficient choice on most systems.
+@end defmac
-@findex STACK_CHECK_PROTECT
-@item STACK_CHECK_PROTECT
+@defmac STACK_CHECK_PROTECT
The number of bytes of stack needed to recover from a stack overflow,
for languages where such a recovery is supported. The default value of
75 words should be adequate for most machines.
+@end defmac
+
+The following macros are relevant only if neither STACK_CHECK_BUILTIN
+nor STACK_CHECK_STATIC_BUILTIN is defined; you can omit them altogether
+in the opposite case.
-@findex STACK_CHECK_MAX_FRAME_SIZE
-@item STACK_CHECK_MAX_FRAME_SIZE
+@defmac STACK_CHECK_MAX_FRAME_SIZE
The maximum size of a stack frame, in bytes. GCC will generate probe
instructions in non-leaf functions to ensure at least this many bytes of
stack are available. If a stack frame is larger than this size, stack
checking will not be reliable and GCC will issue a warning. The
default is chosen so that GCC only generates one instruction on most
systems. You should normally not change the default value of this macro.
+@end defmac
-@findex STACK_CHECK_FIXED_FRAME_SIZE
-@item STACK_CHECK_FIXED_FRAME_SIZE
+@defmac STACK_CHECK_FIXED_FRAME_SIZE
GCC uses this value to generate the above warning message. It
represents the amount of fixed frame used by a function, not including
space for any callee-saved registers, temporaries and user variables.
You need only specify an upper bound for this amount and will normally
use the default of four words.
+@end defmac
-@findex STACK_CHECK_MAX_VAR_SIZE
-@item STACK_CHECK_MAX_VAR_SIZE
+@defmac STACK_CHECK_MAX_VAR_SIZE
The maximum size, in bytes, of an object that GCC will place in the
fixed area of the stack frame when the user specifies
@option{-fstack-check}.
GCC computed the default from the values of the above macros and you will
normally not need to override that default.
-@end table
+@end defmac
@need 2000
@node Frame Registers
@c prevent bad page break with this line
This discusses registers that address the stack frame.
-@table @code
-@findex STACK_POINTER_REGNUM
-@item STACK_POINTER_REGNUM
+@defmac STACK_POINTER_REGNUM
The register number of the stack pointer register, which must also be a
fixed register according to @code{FIXED_REGISTERS}. On most machines,
the hardware determines which register this is.
+@end defmac
-@findex FRAME_POINTER_REGNUM
-@item FRAME_POINTER_REGNUM
+@defmac FRAME_POINTER_REGNUM
The register number of the frame pointer register, which is used to
access automatic variables in the stack frame. On some machines, the
hardware determines which register this is. On other machines, you can
choose any register you wish for this purpose.
+@end defmac
-@findex HARD_FRAME_POINTER_REGNUM
-@item HARD_FRAME_POINTER_REGNUM
+@defmac HARD_FRAME_POINTER_REGNUM
On some machines the offset between the frame pointer and starting
offset of the automatic variables is not known until after register
allocation has been done (for example, because the saved registers are
Do not define this macro if it would be the same as
@code{FRAME_POINTER_REGNUM}.
+@end defmac
-@findex ARG_POINTER_REGNUM
-@item ARG_POINTER_REGNUM
+@defmac ARG_POINTER_REGNUM
The register number of the arg pointer register, which is used to access
the function's argument list. On some machines, this is the same as the
frame pointer register. On some machines, the hardware determines which
pointer register, then you must mark it as a fixed register according to
@code{FIXED_REGISTERS}, or arrange to be able to eliminate it
(@pxref{Elimination}).
+@end defmac
-@findex RETURN_ADDRESS_POINTER_REGNUM
-@item RETURN_ADDRESS_POINTER_REGNUM
+@defmac RETURN_ADDRESS_POINTER_REGNUM
The register number of the return address pointer register, which is used to
access the current function's return address from the stack. On some
machines, the return address is not at a fixed offset from the frame
Do not define this macro unless there is no other way to get the return
address from the stack.
+@end defmac
-@findex STATIC_CHAIN_REGNUM
-@findex STATIC_CHAIN_INCOMING_REGNUM
-@item STATIC_CHAIN_REGNUM
-@itemx STATIC_CHAIN_INCOMING_REGNUM
+@defmac STATIC_CHAIN_REGNUM
+@defmacx STATIC_CHAIN_INCOMING_REGNUM
Register numbers used for passing a function's static chain pointer. If
register windows are used, the register number as seen by the called
function is @code{STATIC_CHAIN_INCOMING_REGNUM}, while the register
If the static chain is passed in memory, these macros should not be
defined; instead, the next two macros should be defined.
+@end defmac
-@findex STATIC_CHAIN
-@findex STATIC_CHAIN_INCOMING
-@item STATIC_CHAIN
-@itemx STATIC_CHAIN_INCOMING
+@defmac STATIC_CHAIN
+@defmacx STATIC_CHAIN_INCOMING
If the static chain is passed in memory, these macros provide rtx giving
@code{mem} expressions that denote where they are stored.
@code{STATIC_CHAIN} and @code{STATIC_CHAIN_INCOMING} give the locations
If the static chain is passed in a register, the two previous macros should
be defined instead.
+@end defmac
-@findex DWARF_FRAME_REGISTERS
-@item DWARF_FRAME_REGISTERS
+@defmac DWARF_FRAME_REGISTERS
This macro specifies the maximum number of hard registers that can be
saved in a call frame. This is used to size data structures used in
DWARF2 exception handling.
If this macro is not defined, it defaults to
@code{FIRST_PSEUDO_REGISTER}.
+@end defmac
-@findex PRE_GCC3_DWARF_FRAME_REGISTERS
-@item PRE_GCC3_DWARF_FRAME_REGISTERS
+@defmac PRE_GCC3_DWARF_FRAME_REGISTERS
This macro is similar to @code{DWARF_FRAME_REGISTERS}, but is provided
for backward compatibility in pre GCC 3.0 compiled code.
If this macro is not defined, it defaults to
@code{DWARF_FRAME_REGISTERS}.
+@end defmac
-@end table
+@defmac DWARF_REG_TO_UNWIND_COLUMN (@var{regno})
+
+Define this macro if the target's representation for dwarf registers
+is different than the internal representation for unwind column.
+Given a dwarf register, this macro should return the internal unwind
+column number to use instead.
+
+See the PowerPC's SPE target for an example.
+@end defmac
+
+@defmac DWARF_FRAME_REGNUM (@var{regno})
+
+Define this macro if the target's representation for dwarf registers
+used in .eh_frame or .debug_frame is different from that used in other
+debug info sections. Given a GCC hard register number, this macro
+should return the .eh_frame register number. The default is
+@code{DBX_REGISTER_NUMBER (@var{regno})}.
+
+@end defmac
+
+@defmac DWARF2_FRAME_REG_OUT (@var{regno}, @var{for_eh})
+
+Define this macro to map register numbers held in the call frame info
+that GCC has collected using @code{DWARF_FRAME_REGNUM} to those that
+should be output in .debug_frame (@code{@var{for_eh}} is zero) and
+.eh_frame (@code{@var{for_eh}} is nonzero). The default is to
+return @code{@var{regno}}.
+
+@end defmac
@node Elimination
@subsection Eliminating Frame Pointer and Arg Pointer
@c prevent bad page break with this line
This is about eliminating the frame pointer and arg pointer.
-@table @code
-@findex FRAME_POINTER_REQUIRED
-@item FRAME_POINTER_REQUIRED
+@defmac FRAME_POINTER_REQUIRED
A C expression which is nonzero if a function must have and use a frame
pointer. This expression is evaluated in the reload pass. If its value is
nonzero the function will have a frame pointer.
In a function that does not require a frame pointer, the frame pointer
register can be allocated for ordinary usage, unless you mark it as a
fixed register. See @code{FIXED_REGISTERS} for more information.
+@end defmac
-@findex INITIAL_FRAME_POINTER_OFFSET
@findex get_frame_size
-@item INITIAL_FRAME_POINTER_OFFSET (@var{depth-var})
+@defmac INITIAL_FRAME_POINTER_OFFSET (@var{depth-var})
A C statement to store in the variable @var{depth-var} the difference
between the frame pointer and the stack pointer values immediately after
the function prologue. The value would be computed from information
need not be defined. Otherwise, it must be defined even if
@code{FRAME_POINTER_REQUIRED} is defined to always be true; in that
case, you may set @var{depth-var} to anything.
+@end defmac
-@findex ELIMINABLE_REGS
-@item ELIMINABLE_REGS
+@defmac ELIMINABLE_REGS
If defined, this macro specifies a table of register pairs used to
eliminate unneeded registers that point into the stack frame. If it is not
defined, the only elimination attempted by the compiler is to replace
depending on whether or not the frame pointer has been eliminated.
In this case, you might specify:
-@example
+@smallexample
#define ELIMINABLE_REGS \
@{@{ARG_POINTER_REGNUM, STACK_POINTER_REGNUM@}, \
@{ARG_POINTER_REGNUM, FRAME_POINTER_REGNUM@}, \
@{FRAME_POINTER_REGNUM, STACK_POINTER_REGNUM@}@}
-@end example
+@end smallexample
Note that the elimination of the argument pointer with the stack pointer is
specified first since that is the preferred elimination.
+@end defmac
-@findex CAN_ELIMINATE
-@item CAN_ELIMINATE (@var{from-reg}, @var{to-reg})
+@defmac CAN_ELIMINATE (@var{from-reg}, @var{to-reg})
A C expression that returns nonzero if the compiler is allowed to try
to replace register number @var{from-reg} with register number
@var{to-reg}. This macro need only be defined if @code{ELIMINABLE_REGS}
is defined, and will usually be the constant 1, since most of the cases
preventing register elimination are things that the compiler already
knows about.
+@end defmac
-@findex INITIAL_ELIMINATION_OFFSET
-@item INITIAL_ELIMINATION_OFFSET (@var{from-reg}, @var{to-reg}, @var{offset-var})
+@defmac INITIAL_ELIMINATION_OFFSET (@var{from-reg}, @var{to-reg}, @var{offset-var})
This macro is similar to @code{INITIAL_FRAME_POINTER_OFFSET}. It
specifies the initial difference between the specified pair of
registers. This macro must be defined if @code{ELIMINABLE_REGS} is
defined.
-@end table
+@end defmac
@node Stack Arguments
@subsection Passing Function Arguments on the Stack
on the stack. See the following section for other macros that
control passing certain arguments in registers.
-@table @code
-@findex PROMOTE_PROTOTYPES
-@item PROMOTE_PROTOTYPES
-A C expression whose value is nonzero if an argument declared in
-a prototype as an integral type smaller than @code{int} should
-actually be passed as an @code{int}. In addition to avoiding
-errors in certain cases of mismatch, it also makes for better
-code on certain machines. If the macro is not defined in target
-header files, it defaults to 0.
-
-@findex PUSH_ARGS
-@item PUSH_ARGS
+@deftypefn {Target Hook} bool TARGET_PROMOTE_PROTOTYPES (tree @var{fntype})
+This target hook returns @code{true} if an argument declared in a
+prototype as an integral type smaller than @code{int} should actually be
+passed as an @code{int}. In addition to avoiding errors in certain
+cases of mismatch, it also makes for better code on certain machines.
+The default is to not promote prototypes.
+@end deftypefn
+
+@defmac PUSH_ARGS
A C expression. If nonzero, push insns will be used to pass
outgoing arguments.
If the target machine does not have a push instruction, set it to zero.
That directs GCC to use an alternate strategy: to
allocate the entire argument block and then store the arguments into
it. When @code{PUSH_ARGS} is nonzero, @code{PUSH_ROUNDING} must be defined too.
+@end defmac
+
+@defmac PUSH_ARGS_REVERSED
+A C expression. If nonzero, function arguments will be evaluated from
+last to first, rather than from first to last. If this macro is not
+defined, it defaults to @code{PUSH_ARGS} on targets where the stack
+and args grow in opposite directions, and 0 otherwise.
+@end defmac
-@findex PUSH_ROUNDING
-@item PUSH_ROUNDING (@var{npushed})
+@defmac PUSH_ROUNDING (@var{npushed})
A C expression that is the number of bytes actually pushed onto the
stack when an instruction attempts to push @var{npushed} bytes.
On some machines, the definition
-@example
+@smallexample
#define PUSH_ROUNDING(BYTES) (BYTES)
-@end example
+@end smallexample
@noindent
will suffice. But on other machines, instructions that appear
to push one byte actually push two bytes in an attempt to maintain
alignment. Then the definition should be
-@example
+@smallexample
#define PUSH_ROUNDING(BYTES) (((BYTES) + 1) & ~1)
-@end example
+@end smallexample
+@end defmac
-@findex ACCUMULATE_OUTGOING_ARGS
@findex current_function_outgoing_args_size
-@item ACCUMULATE_OUTGOING_ARGS
+@defmac ACCUMULATE_OUTGOING_ARGS
A C expression. If nonzero, the maximum amount of space required for outgoing arguments
will be computed and placed into the variable
@code{current_function_outgoing_args_size}. No space will be pushed
Setting both @code{PUSH_ARGS} and @code{ACCUMULATE_OUTGOING_ARGS}
is not proper.
+@end defmac
-@findex REG_PARM_STACK_SPACE
-@item REG_PARM_STACK_SPACE (@var{fndecl})
+@defmac REG_PARM_STACK_SPACE (@var{fndecl})
Define this macro if functions should assume that stack space has been
allocated for arguments even when their values are passed in
registers.
The value of this macro is the size, in bytes, of the area reserved for
arguments passed in registers for the function represented by @var{fndecl},
which can be zero if GCC is calling a library function.
+The argument @var{fndecl} can be the FUNCTION_DECL, or the type itself
+of the function.
This space can be allocated by the caller, or be a part of the
machine-dependent stack frame: @code{OUTGOING_REG_PARM_STACK_SPACE} says
which.
+@end defmac
@c above is overfull. not sure what to do. --mew 5feb93 did
@c something, not sure if it looks good. --mew 10feb93
-@findex MAYBE_REG_PARM_STACK_SPACE
-@findex FINAL_REG_PARM_STACK_SPACE
-@item MAYBE_REG_PARM_STACK_SPACE
-@itemx FINAL_REG_PARM_STACK_SPACE (@var{const_size}, @var{var_size})
-Define these macros in addition to the one above if functions might
-allocate stack space for arguments even when their values are passed
-in registers. These should be used when the stack space allocated
-for arguments in registers is not a simple constant independent of the
-function declaration.
-
-The value of the first macro is the size, in bytes, of the area that
-we should initially assume would be reserved for arguments passed in registers.
-
-The value of the second macro is the actual size, in bytes, of the area
-that will be reserved for arguments passed in registers. This takes two
-arguments: an integer representing the number of bytes of fixed sized
-arguments on the stack, and a tree representing the number of bytes of
-variable sized arguments on the stack.
-
-When these macros are defined, @code{REG_PARM_STACK_SPACE} will only be
-called for libcall functions, the current function, or for a function
-being called when it is known that such stack space must be allocated.
-In each case this value can be easily computed.
-
-When deciding whether a called function needs such stack space, and how
-much space to reserve, GCC uses these two macros instead of
-@code{REG_PARM_STACK_SPACE}.
-
-@findex OUTGOING_REG_PARM_STACK_SPACE
-@item OUTGOING_REG_PARM_STACK_SPACE
-Define this if it is the responsibility of the caller to allocate the area
-reserved for arguments passed in registers.
+@defmac OUTGOING_REG_PARM_STACK_SPACE (@var{fntype})
+Define this to a nonzero value if it is the responsibility of the
+caller to allocate the area reserved for arguments passed in registers
+when calling a function of @var{fntype}. @var{fntype} may be NULL
+if the function called is a library function.
If @code{ACCUMULATE_OUTGOING_ARGS} is defined, this macro controls
whether the space for these arguments counts in the value of
@code{current_function_outgoing_args_size}.
+@end defmac
-@findex STACK_PARMS_IN_REG_PARM_AREA
-@item STACK_PARMS_IN_REG_PARM_AREA
+@defmac STACK_PARMS_IN_REG_PARM_AREA
Define this macro if @code{REG_PARM_STACK_SPACE} is defined, but the
stack parameters don't skip the area specified by it.
@c i changed this, makes more sens and it should have taken care of the
stack beyond the @code{REG_PARM_STACK_SPACE} area. Defining this macro
suppresses this behavior and causes the parameter to be passed on the
stack in its natural location.
+@end defmac
-@findex RETURN_POPS_ARGS
-@item RETURN_POPS_ARGS (@var{fundecl}, @var{funtype}, @var{stack-size})
+@defmac RETURN_POPS_ARGS (@var{fundecl}, @var{funtype}, @var{stack-size})
A C expression that should indicate the number of bytes of its own
arguments that a function pops on returning, or 0 if the
function pops no arguments and the caller must therefore pop them all
nothing (the caller pops all). When this convention is in use,
@var{funtype} is examined to determine whether a function takes a fixed
number of arguments.
+@end defmac
-@findex CALL_POPS_ARGS
-@item CALL_POPS_ARGS (@var{cum})
+@defmac CALL_POPS_ARGS (@var{cum})
A C expression that should indicate the number of bytes a call sequence
pops off the stack. It is added to the value of @code{RETURN_POPS_ARGS}
when compiling a function call.
that have been passed to the function. Since this is a property of the
call site, not of the called function, @code{RETURN_POPS_ARGS} is not
appropriate.
-
-@end table
+@end defmac
@node Register Arguments
@subsection Passing Arguments in Registers
types of arguments are passed in registers or how they are arranged in
the stack.
-@table @code
-@findex FUNCTION_ARG
-@item FUNCTION_ARG (@var{cum}, @var{mode}, @var{type}, @var{named})
+@defmac FUNCTION_ARG (@var{cum}, @var{mode}, @var{type}, @var{named})
A C expression that controls whether a function argument is passed
in a register, and which register.
The value of the expression can also be a @code{parallel} RTX@. This is
used when an argument is passed in multiple locations. The mode of the
-of the @code{parallel} should be the mode of the entire argument. The
+@code{parallel} should be the mode of the entire argument. The
@code{parallel} holds any number of @code{expr_list} pairs; each one
describes where part of the argument is passed. In each
@code{expr_list} the first operand must be a @code{reg} RTX for the hard
nameless arguments to be passed on the stack instead. This is done
by making @code{FUNCTION_ARG} return 0 whenever @var{named} is 0.
-@cindex @code{MUST_PASS_IN_STACK}, and @code{FUNCTION_ARG}
+@cindex @code{TARGET_MUST_PASS_IN_STACK}, and @code{FUNCTION_ARG}
@cindex @code{REG_PARM_STACK_SPACE}, and @code{FUNCTION_ARG}
-You may use the macro @code{MUST_PASS_IN_STACK (@var{mode}, @var{type})}
+You may use the hook @code{targetm.calls.must_pass_in_stack}
in the definition of this macro to determine if this argument is of a
type that must be passed in the stack. If @code{REG_PARM_STACK_SPACE}
is not defined and @code{FUNCTION_ARG} returns nonzero for such an
argument, the compiler will abort. If @code{REG_PARM_STACK_SPACE} is
defined, the argument will be computed in the stack and then loaded into
a register.
+@end defmac
-@findex MUST_PASS_IN_STACK
-@item MUST_PASS_IN_STACK (@var{mode}, @var{type})
-Define as a C expression that evaluates to nonzero if we do not know how
-to pass TYPE solely in registers. The file @file{expr.h} defines a
+@deftypefn {Target Hook} bool TARGET_MUST_PASS_IN_STACK (enum machine_mode @var{mode}, tree @var{type})
+This target hook should return @code{true} if we should not pass @var{type}
+solely in registers. The file @file{expr.h} defines a
definition that is usually appropriate, refer to @file{expr.h} for additional
documentation.
+@end deftypefn
-@findex FUNCTION_INCOMING_ARG
-@item FUNCTION_INCOMING_ARG (@var{cum}, @var{mode}, @var{type}, @var{named})
+@defmac FUNCTION_INCOMING_ARG (@var{cum}, @var{mode}, @var{type}, @var{named})
Define this macro if the target machine has ``register windows'', so
that the register in which a function sees an arguments is not
necessarily the same as the one in which the caller passed the
If @code{FUNCTION_INCOMING_ARG} is not defined, @code{FUNCTION_ARG}
serves both purposes.
+@end defmac
-@findex FUNCTION_ARG_PARTIAL_NREGS
-@item FUNCTION_ARG_PARTIAL_NREGS (@var{cum}, @var{mode}, @var{type}, @var{named})
-A C expression for the number of words, at the beginning of an
-argument, that must be put in registers. The value must be zero for
+@deftypefn {Target Hook} int TARGET_ARG_PARTIAL_BYTES (CUMULATIVE_ARGS *@var{cum}, enum machine_mode @var{mode}, tree @var{type}, bool @var{named})
+This target hook returns the number of bytes at the beginning of an
+argument that must be put in registers. The value must be zero for
arguments that are passed entirely in registers or that are entirely
pushed on the stack.
On some machines, certain arguments must be passed partially in
registers and partially in memory. On these machines, typically the
-first @var{n} words of arguments are passed in registers, and the rest
+first few words of arguments are passed in registers, and the rest
on the stack. If a multi-word argument (a @code{double} or a
structure) crosses that boundary, its first few words must be passed
in registers and the rest must be pushed. This macro tells the
-compiler when this occurs, and how many of the words should go in
-registers.
+compiler when this occurs, and how many bytes should go in registers.
@code{FUNCTION_ARG} for these arguments should return the first
register to be used by the caller for this argument; likewise
@code{FUNCTION_INCOMING_ARG}, for the called function.
+@end deftypefn
+
+@deftypefn {Target Hook} bool TARGET_PASS_BY_REFERENCE (CUMULATIVE_ARGS *@var{cum}, enum machine_mode @var{mode}, tree @var{type}, bool @var{named})
+This target hook should return @code{true} if an argument at the
+position indicated by @var{cum} should be passed by reference. This
+predicate is queried after target independent reasons for being
+passed by reference, such as @code{TREE_ADDRESSABLE (type)}.
-@findex FUNCTION_ARG_PASS_BY_REFERENCE
-@item FUNCTION_ARG_PASS_BY_REFERENCE (@var{cum}, @var{mode}, @var{type}, @var{named})
-A C expression that indicates when an argument must be passed by reference.
-If nonzero for an argument, a copy of that argument is made in memory and a
+If the hook returns true, a copy of that argument is made in memory and a
pointer to the argument is passed instead of the argument itself.
The pointer is passed in whatever way is appropriate for passing a pointer
to that type.
+@end deftypefn
-On machines where @code{REG_PARM_STACK_SPACE} is not defined, a suitable
-definition of this macro might be
-@smallexample
-#define FUNCTION_ARG_PASS_BY_REFERENCE\
-(CUM, MODE, TYPE, NAMED) \
- MUST_PASS_IN_STACK (MODE, TYPE)
-@end smallexample
-@c this is *still* too long. --mew 5feb93
-
-@findex FUNCTION_ARG_CALLEE_COPIES
-@item FUNCTION_ARG_CALLEE_COPIES (@var{cum}, @var{mode}, @var{type}, @var{named})
-If defined, a C expression that indicates when it is the called function's
-responsibility to make a copy of arguments passed by invisible reference.
-Normally, the caller makes a copy and passes the address of the copy to the
-routine being called. When @code{FUNCTION_ARG_CALLEE_COPIES} is defined and is
-nonzero, the caller does not make a copy. Instead, it passes a pointer to the
-``live'' value. The called function must not modify this value. If it can be
-determined that the value won't be modified, it need not make a copy;
-otherwise a copy must be made.
-
-@findex FUNCTION_ARG_REG_LITTLE_ENDIAN
-@item FUNCTION_ARG_REG_LITTLE_ENDIAN
-If defined TRUE on a big-endian system then structure arguments passed
-(and returned) in registers are passed in a little-endian manner instead of
-the big-endian manner. On the HP-UX IA64 and PA64 platforms structures are
-aligned differently then integral values and setting this value to true will
-allow for the special handling of structure arguments and return values.
-
-@findex CUMULATIVE_ARGS
-@item CUMULATIVE_ARGS
+@deftypefn {Target Hook} bool TARGET_CALLEE_COPIES (CUMULATIVE_ARGS *@var{cum}, enum machine_mode @var{mode}, tree @var{type}, bool @var{named})
+The function argument described by the parameters to this hook is
+known to be passed by reference. The hook should return true if the
+function argument should be copied by the callee instead of copied
+by the caller.
+
+For any argument for which the hook returns true, if it can be
+determined that the argument is not modified, then a copy need
+not be generated.
+
+The default version of this hook always returns false.
+@end deftypefn
+
+@defmac CUMULATIVE_ARGS
A C type for declaring a variable that is used as the first argument of
@code{FUNCTION_ARG} and other related values. For some target machines,
the type @code{int} suffices and can hold the number of bytes of
arguments are passed on the stack, there is no need to store anything in
@code{CUMULATIVE_ARGS}; however, the data structure must exist and
should not be empty, so use @code{int}.
-
-@findex INIT_CUMULATIVE_ARGS
-@item INIT_CUMULATIVE_ARGS (@var{cum}, @var{fntype}, @var{libname}, @var{indirect})
-A C statement (sans semicolon) for initializing the variable @var{cum}
-for the state at the beginning of the argument list. The variable has
-type @code{CUMULATIVE_ARGS}. The value of @var{fntype} is the tree node
-for the data type of the function which will receive the args, or 0
-if the args are to a compiler support library function. The value of
-@var{indirect} is nonzero when processing an indirect call, for example
-a call through a function pointer. The value of @var{indirect} is zero
-for a call to an explicitly named function, a library function call, or when
+@end defmac
+
+@defmac OVERRIDE_ABI_FORMAT (@var{fndecl})
+If defined, this macro is called before generating any code for a
+function, but after the @var{cfun} descriptor for the function has been
+created. The back end may use this macro to update @var{cfun} to
+reflect an ABI other than that which would normally be used by default.
+If the compiler is generating code for a compiler-generated function,
+@var{fndecl} may be @code{NULL}.
+@end defmac
+
+@defmac INIT_CUMULATIVE_ARGS (@var{cum}, @var{fntype}, @var{libname}, @var{fndecl}, @var{n_named_args})
+A C statement (sans semicolon) for initializing the variable
+@var{cum} for the state at the beginning of the argument list. The
+variable has type @code{CUMULATIVE_ARGS}. The value of @var{fntype}
+is the tree node for the data type of the function which will receive
+the args, or 0 if the args are to a compiler support library function.
+For direct calls that are not libcalls, @var{fndecl} contain the
+declaration node of the function. @var{fndecl} is also set when
@code{INIT_CUMULATIVE_ARGS} is used to find arguments for the function
-being compiled.
+being compiled. @var{n_named_args} is set to the number of named
+arguments, including a structure return address if it is passed as a
+parameter, when making a call. When processing incoming arguments,
+@var{n_named_args} is set to @minus{}1.
When processing a call to a compiler support library function,
@var{libname} identifies which one. It is a @code{symbol_ref} rtx which
an ordinary C function call is being processed. Thus, each time this
macro is called, either @var{libname} or @var{fntype} is nonzero, but
never both of them at once.
+@end defmac
-@findex INIT_CUMULATIVE_LIBCALL_ARGS
-@item INIT_CUMULATIVE_LIBCALL_ARGS (@var{cum}, @var{mode}, @var{libname})
+@defmac INIT_CUMULATIVE_LIBCALL_ARGS (@var{cum}, @var{mode}, @var{libname})
Like @code{INIT_CUMULATIVE_ARGS} but only used for outgoing libcalls,
it gets a @code{MODE} argument instead of @var{fntype}, that would be
@code{NULL}. @var{indirect} would always be zero, too. If this macro
is not defined, @code{INIT_CUMULATIVE_ARGS (cum, NULL_RTX, libname,
0)} is used instead.
+@end defmac
-@findex INIT_CUMULATIVE_INCOMING_ARGS
-@item INIT_CUMULATIVE_INCOMING_ARGS (@var{cum}, @var{fntype}, @var{libname})
+@defmac INIT_CUMULATIVE_INCOMING_ARGS (@var{cum}, @var{fntype}, @var{libname})
Like @code{INIT_CUMULATIVE_ARGS} but overrides it for the purposes of
finding the arguments for the function being compiled. If this macro is
undefined, @code{INIT_CUMULATIVE_ARGS} is used instead.
@code{INIT_CUMULATIVE_ARGS}.
@c could use "this macro" in place of @code{INIT_CUMULATIVE_ARGS}, maybe.
@c --mew 5feb93 i switched the order of the sentences. --mew 10feb93
+@end defmac
-@findex FUNCTION_ARG_ADVANCE
-@item FUNCTION_ARG_ADVANCE (@var{cum}, @var{mode}, @var{type}, @var{named})
+@defmac FUNCTION_ARG_ADVANCE (@var{cum}, @var{mode}, @var{type}, @var{named})
A C statement (sans semicolon) to update the summarizer variable
@var{cum} to advance past an argument in the argument list. The
values @var{mode}, @var{type} and @var{named} describe that argument.
This macro need not do anything if the argument in question was passed
on the stack. The compiler knows how to track the amount of stack space
used for arguments without any special help.
+@end defmac
+
+
+@defmac FUNCTION_ARG_OFFSET (@var{mode}, @var{type})
+If defined, a C expression that is the number of bytes to add to the
+offset of the argument passed in memory. This is needed for the SPU,
+which passes @code{char} and @code{short} arguments in the preferred
+slot that is in the middle of the quad word instead of starting at the
+top.
+@end defmac
-@findex FUNCTION_ARG_PADDING
-@item FUNCTION_ARG_PADDING (@var{mode}, @var{type})
+@defmac FUNCTION_ARG_PADDING (@var{mode}, @var{type})
If defined, a C expression which determines whether, and in which direction,
to pad out an argument with extra space. The value should be of type
@code{enum direction}: either @code{upward} to pad above the argument,
For little-endian machines, the default is to pad upward. For
big-endian machines, the default is to pad downward for an argument of
constant size shorter than an @code{int}, and upward otherwise.
+@end defmac
-@findex PAD_VARARGS_DOWN
-@item PAD_VARARGS_DOWN
+@defmac PAD_VARARGS_DOWN
If defined, a C expression which determines whether the default
implementation of va_arg will attempt to pad down before reading the
next argument, if that argument is smaller than its aligned space as
controlled by @code{PARM_BOUNDARY}. If this macro is not defined, all such
arguments are padded down if @code{BYTES_BIG_ENDIAN} is true.
+@end defmac
+
+@defmac BLOCK_REG_PADDING (@var{mode}, @var{type}, @var{first})
+Specify padding for the last element of a block move between registers and
+memory. @var{first} is nonzero if this is the only element. Defining this
+macro allows better control of register function parameters on big-endian
+machines, without using @code{PARALLEL} rtl. In particular,
+@code{MUST_PASS_IN_STACK} need not test padding and mode of types in
+registers, as there is no longer a "wrong" part of a register; For example,
+a three byte aggregate may be passed in the high part of a register if so
+required.
+@end defmac
-@findex FUNCTION_ARG_BOUNDARY
-@item FUNCTION_ARG_BOUNDARY (@var{mode}, @var{type})
+@defmac FUNCTION_ARG_BOUNDARY (@var{mode}, @var{type})
If defined, a C expression that gives the alignment boundary, in bits,
of an argument with the specified mode and type. If it is not defined,
@code{PARM_BOUNDARY} is used for all arguments.
+@end defmac
-@findex FUNCTION_ARG_REGNO_P
-@item FUNCTION_ARG_REGNO_P (@var{regno})
+@defmac FUNCTION_ARG_REGNO_P (@var{regno})
A C expression that is nonzero if @var{regno} is the number of a hard
register in which function arguments are sometimes passed. This does
@emph{not} include implicit arguments such as the static chain and
the structure-value address. On many machines, no registers can be
used for this purpose since all function arguments are pushed on the
stack.
+@end defmac
+
+@deftypefn {Target Hook} bool TARGET_SPLIT_COMPLEX_ARG (tree @var{type})
+This hook should return true if parameter of type @var{type} are passed
+as two scalar parameters. By default, GCC will attempt to pack complex
+arguments into the target's word size. Some ABIs require complex arguments
+to be split and treated as their individual components. For example, on
+AIX64, complex floats should be passed in a pair of floating point
+registers, even though a complex float would fit in one 64-bit floating
+point register.
+
+The default value of this hook is @code{NULL}, which is treated as always
+false.
+@end deftypefn
-@findex LOAD_ARGS_REVERSED
-@item LOAD_ARGS_REVERSED
-If defined, the order in which arguments are loaded into their
-respective argument registers is reversed so that the last
-argument is loaded first. This macro only affects arguments
-passed in registers.
+@deftypefn {Target Hook} tree TARGET_BUILD_BUILTIN_VA_LIST (void)
+This hook returns a type node for @code{va_list} for the target.
+The default version of the hook returns @code{void*}.
+@end deftypefn
-@end table
+@deftypefn {Target Hook} tree TARGET_FN_ABI_VA_LIST (tree @var{fndecl})
+This hook returns the va_list type of the calling convention specified by
+@var{fndecl}.
+The default version of this hook returns @code{va_list_type_node}.
+@end deftypefn
+
+@deftypefn {Target Hook} tree TARGET_CANONICAL_VA_LIST_TYPE (tree @var{type})
+This hook returns the va_list type of the calling convention specified by the
+type of @var{type}. If @var{type} is not a valid va_list type, it returns
+@code{NULL_TREE}.
+@end deftypefn
+
+@deftypefn {Target Hook} tree TARGET_GIMPLIFY_VA_ARG_EXPR (tree @var{valist}, tree @var{type}, tree *@var{pre_p}, tree *@var{post_p})
+This hook performs target-specific gimplification of
+@code{VA_ARG_EXPR}. The first two parameters correspond to the
+arguments to @code{va_arg}; the latter two are as in
+@code{gimplify.c:gimplify_expr}.
+@end deftypefn
+
+@deftypefn {Target Hook} bool TARGET_VALID_POINTER_MODE (enum machine_mode @var{mode})
+Define this to return nonzero if the port can handle pointers
+with machine mode @var{mode}. The default version of this
+hook returns true for both @code{ptr_mode} and @code{Pmode}.
+@end deftypefn
+
+@deftypefn {Target Hook} bool TARGET_SCALAR_MODE_SUPPORTED_P (enum machine_mode @var{mode})
+Define this to return nonzero if the port is prepared to handle
+insns involving scalar mode @var{mode}. For a scalar mode to be
+considered supported, all the basic arithmetic and comparisons
+must work.
+
+The default version of this hook returns true for any mode
+required to handle the basic C types (as defined by the port).
+Included here are the double-word arithmetic supported by the
+code in @file{optabs.c}.
+@end deftypefn
+
+@deftypefn {Target Hook} bool TARGET_VECTOR_MODE_SUPPORTED_P (enum machine_mode @var{mode})
+Define this to return nonzero if the port is prepared to handle
+insns involving vector mode @var{mode}. At the very least, it
+must have move patterns for this mode.
+@end deftypefn
@node Scalar Return
@subsection How Scalar Function Values Are Returned
This section discusses the macros that control returning scalars as
values---values that can fit in registers.
-@table @code
-@findex TRADITIONAL_RETURN_FLOAT
-@item TRADITIONAL_RETURN_FLOAT
-Define this macro if @option{-traditional} should not cause functions
-declared to return @code{float} to convert the value to @code{double}.
-
-@findex FUNCTION_VALUE
-@item FUNCTION_VALUE (@var{valtype}, @var{func})
-A C expression to create an RTX representing the place where a
-function returns a value of data type @var{valtype}. @var{valtype} is
-a tree node representing a data type. Write @code{TYPE_MODE
-(@var{valtype})} to get the machine mode used to represent that type.
-On many machines, only the mode is relevant. (Actually, on most
-machines, scalar values are returned in the same place regardless of
-mode).
-
-The value of the expression is usually a @code{reg} RTX for the hard
-register where the return value is stored. The value can also be a
-@code{parallel} RTX, if the return value is in multiple places. See
-@code{FUNCTION_ARG} for an explanation of the @code{parallel} form.
-
-If @code{PROMOTE_FUNCTION_RETURN} is defined, you must apply the same
-promotion rules specified in @code{PROMOTE_MODE} if @var{valtype} is a
-scalar type.
+@deftypefn {Target Hook} rtx TARGET_FUNCTION_VALUE (tree @var{ret_type}, tree @var{fn_decl_or_type}, bool @var{outgoing})
+
+Define this to return an RTX representing the place where a function
+returns or receives a value of data type @var{ret_type}, a tree node
+node representing a data type. @var{fn_decl_or_type} is a tree node
+representing @code{FUNCTION_DECL} or @code{FUNCTION_TYPE} of a
+function being called. If @var{outgoing} is false, the hook should
+compute the register in which the caller will see the return value.
+Otherwise, the hook should return an RTX representing the place where
+a function returns a value.
+
+On many machines, only @code{TYPE_MODE (@var{ret_type})} is relevant.
+(Actually, on most machines, scalar values are returned in the same
+place regardless of mode.) The value of the expression is usually a
+@code{reg} RTX for the hard register where the return value is stored.
+The value can also be a @code{parallel} RTX, if the return value is in
+multiple places. See @code{FUNCTION_ARG} for an explanation of the
+@code{parallel} form. Note that the callee will populate every
+location specified in the @code{parallel}, but if the first element of
+the @code{parallel} contains the whole return value, callers will use
+that element as the canonical location and ignore the others. The m68k
+port uses this type of @code{parallel} to return pointers in both
+@samp{%a0} (the canonical location) and @samp{%d0}.
+
+If @code{TARGET_PROMOTE_FUNCTION_RETURN} returns true, you must apply
+the same promotion rules specified in @code{PROMOTE_MODE} if
+@var{valtype} is a scalar type.
If the precise function being called is known, @var{func} is a tree
node (@code{FUNCTION_DECL}) for it; otherwise, @var{func} is a null
convention for specific functions when all their calls are
known.
-@code{FUNCTION_VALUE} is not used for return vales with aggregate data
-types, because these are returned in another way. See
-@code{STRUCT_VALUE_REGNUM} and related macros, below.
-
-@findex FUNCTION_OUTGOING_VALUE
-@item FUNCTION_OUTGOING_VALUE (@var{valtype}, @var{func})
-Define this macro if the target machine has ``register windows''
-so that the register in which a function returns its value is not
-the same as the one in which the caller sees the value.
+Some target machines have ``register windows'' so that the register in
+which a function returns its value is not the same as the one in which
+the caller sees the value. For such machines, you should return
+different RTX depending on @var{outgoing}.
-For such machines, @code{FUNCTION_VALUE} computes the register in which
-the caller will see the value. @code{FUNCTION_OUTGOING_VALUE} should be
-defined in a similar fashion to tell the function where to put the
-value.
+@code{TARGET_FUNCTION_VALUE} is not used for return values with
+aggregate data types, because these are returned in another way. See
+@code{TARGET_STRUCT_VALUE_RTX} and related macros, below.
+@end deftypefn
-If @code{FUNCTION_OUTGOING_VALUE} is not defined,
-@code{FUNCTION_VALUE} serves both purposes.
+@defmac FUNCTION_VALUE (@var{valtype}, @var{func})
+This macro has been deprecated. Use @code{TARGET_FUNCTION_VALUE} for
+a new target instead.
+@end defmac
-@code{FUNCTION_OUTGOING_VALUE} is not used for return vales with
-aggregate data types, because these are returned in another way. See
-@code{STRUCT_VALUE_REGNUM} and related macros, below.
+@defmac FUNCTION_OUTGOING_VALUE (@var{valtype}, @var{func})
+This macro has been deprecated. Use @code{TARGET_FUNCTION_VALUE} for
+a new target instead.
+@end defmac
-@findex LIBCALL_VALUE
-@item LIBCALL_VALUE (@var{mode})
+@defmac LIBCALL_VALUE (@var{mode})
A C expression to create an RTX representing the place where a library
-function returns a value of mode @var{mode}. If the precise function
-being called is known, @var{func} is a tree node
-(@code{FUNCTION_DECL}) for it; otherwise, @var{func} is a null
-pointer. This makes it possible to use a different value-returning
-convention for specific functions when all their calls are
-known.
+function returns a value of mode @var{mode}.
Note that ``library function'' in this context means a compiler
support routine, used to perform arithmetic, whose name is known
specially by the compiler and was not mentioned in the C code being
compiled.
+@end defmac
-The definition of @code{LIBRARY_VALUE} need not be concerned aggregate
-data types, because none of the library functions returns such types.
-
-@findex FUNCTION_VALUE_REGNO_P
-@item FUNCTION_VALUE_REGNO_P (@var{regno})
+@defmac FUNCTION_VALUE_REGNO_P (@var{regno})
A C expression that is nonzero if @var{regno} is the number of a hard
register in which the values of called function may come back.
recognized by this macro. So for most machines, this definition
suffices:
-@example
+@smallexample
#define FUNCTION_VALUE_REGNO_P(N) ((N) == 0)
-@end example
+@end smallexample
If the machine has register windows, so that the caller and the called
function use different registers for the return value, this macro
should recognize only the caller's register numbers.
+@end defmac
-@findex APPLY_RESULT_SIZE
-@item APPLY_RESULT_SIZE
+@defmac TARGET_ENUM_VA_LIST (@var{idx}, @var{pname}, @var{ptype})
+This target macro is used in function @code{c_common_nodes_and_builtins}
+to iterate through the target specific builtin types for va_list. The
+variable @var{idx} is used as iterator. @var{pname} has to be a pointer
+to a @code{const char *} and @var{ptype} a pointer to a @code{tree} typed
+variable.
+The arguments @var{pname} and @var{ptype} are used to store the result of
+this macro and are set to the name of the va_list builtin type and its
+internal type.
+If the return value of this macro is zero, then there is no more element.
+Otherwise the @var{IDX} should be increased for the next call of this
+macro to iterate through all types.
+@end defmac
+
+@defmac APPLY_RESULT_SIZE
Define this macro if @samp{untyped_call} and @samp{untyped_return}
need more space than is implied by @code{FUNCTION_VALUE_REGNO_P} for
saving and restoring an arbitrary return value.
-@end table
+@end defmac
+
+@deftypefn {Target Hook} bool TARGET_RETURN_IN_MSB (tree @var{type})
+This hook should return true if values of type @var{type} are returned
+at the most significant end of a register (in other words, if they are
+padded at the least significant end). You can assume that @var{type}
+is returned in a register; the caller is required to check this.
+
+Note that the register provided by @code{TARGET_FUNCTION_VALUE} must
+be able to hold the complete return value. For example, if a 1-, 2-
+or 3-byte structure is returned at the most significant end of a
+4-byte register, @code{TARGET_FUNCTION_VALUE} should provide an
+@code{SImode} rtx.
+@end deftypefn
@node Aggregate Return
@subsection How Large Values Are Returned
@cindex structure value address
When a function value's mode is @code{BLKmode} (and in some other
-cases), the value is not returned according to @code{FUNCTION_VALUE}
-(@pxref{Scalar Return}). Instead, the caller passes the address of a
-block of memory in which the value should be stored. This address
-is called the @dfn{structure value address}.
+cases), the value is not returned according to
+@code{TARGET_FUNCTION_VALUE} (@pxref{Scalar Return}). Instead, the
+caller passes the address of a block of memory in which the value
+should be stored. This address is called the @dfn{structure value
+address}.
This section describes how to control returning structure values in
memory.
-@table @code
-@findex RETURN_IN_MEMORY
-@item RETURN_IN_MEMORY (@var{type})
-A C expression which can inhibit the returning of certain function
-values in registers, based on the type of value. A nonzero value says
-to return the function value in memory, just as large structures are
-always returned. Here @var{type} will be a C expression of type
-@code{tree}, representing the data type of the value.
+@deftypefn {Target Hook} bool TARGET_RETURN_IN_MEMORY (tree @var{type}, tree @var{fntype})
+This target hook should return a nonzero value to say to return the
+function value in memory, just as large structures are always returned.
+Here @var{type} will be the data type of the value, and @var{fntype}
+will be the type of the function doing the returning, or @code{NULL} for
+libcalls.
Note that values of mode @code{BLKmode} must be explicitly handled
-by this macro. Also, the option @option{-fpcc-struct-return}
+by this function. Also, the option @option{-fpcc-struct-return}
takes effect regardless of this macro. On most systems, it is
-possible to leave the macro undefined; this causes a default
+possible to leave the hook undefined; this causes a default
definition to be used, whose value is the constant 1 for @code{BLKmode}
values, and 0 otherwise.
-Do not use this macro to indicate that structures and unions should always
+Do not use this hook to indicate that structures and unions should always
be returned in memory. You should instead use @code{DEFAULT_PCC_STRUCT_RETURN}
to indicate this.
+@end deftypefn
-@findex DEFAULT_PCC_STRUCT_RETURN
-@item DEFAULT_PCC_STRUCT_RETURN
+@defmac DEFAULT_PCC_STRUCT_RETURN
Define this macro to be 1 if all structure and union return values must be
in memory. Since this results in slower code, this should be defined
only if needed for compatibility with other compilers or with an ABI@.
If you define this macro to be 0, then the conventions used for structure
-and union return values are decided by the @code{RETURN_IN_MEMORY} macro.
+and union return values are decided by the @code{TARGET_RETURN_IN_MEMORY}
+target hook.
If not defined, this defaults to the value 1.
+@end defmac
+
+@deftypefn {Target Hook} rtx TARGET_STRUCT_VALUE_RTX (tree @var{fndecl}, int @var{incoming})
+This target hook should return the location of the structure value
+address (normally a @code{mem} or @code{reg}), or 0 if the address is
+passed as an ``invisible'' first argument. Note that @var{fndecl} may
+be @code{NULL}, for libcalls. You do not need to define this target
+hook if the address is always passed as an ``invisible'' first
+argument.
-@findex STRUCT_VALUE_REGNUM
-@item STRUCT_VALUE_REGNUM
-If the structure value address is passed in a register, then
-@code{STRUCT_VALUE_REGNUM} should be the number of that register.
-
-@findex STRUCT_VALUE
-@item STRUCT_VALUE
-If the structure value address is not passed in a register, define
-@code{STRUCT_VALUE} as an expression returning an RTX for the place
-where the address is passed. If it returns 0, the address is passed as
-an ``invisible'' first argument.
-
-@findex STRUCT_VALUE_INCOMING_REGNUM
-@item STRUCT_VALUE_INCOMING_REGNUM
On some architectures the place where the structure value address
is found by the called function is not the same place that the
caller put it. This can be due to register windows, or it could
be because the function prologue moves it to a different place.
+@var{incoming} is @code{1} or @code{2} when the location is needed in
+the context of the called function, and @code{0} in the context of
+the caller.
+
+If @var{incoming} is nonzero and the address is to be found on the
+stack, return a @code{mem} which refers to the frame pointer. If
+@var{incoming} is @code{2}, the result is being used to fetch the
+structure value address at the beginning of a function. If you need
+to emit adjusting code, you should do it at this point.
+@end deftypefn
-If the incoming location of the structure value address is in a
-register, define this macro as the register number.
-
-@findex STRUCT_VALUE_INCOMING
-@item STRUCT_VALUE_INCOMING
-If the incoming location is not a register, then you should define
-@code{STRUCT_VALUE_INCOMING} as an expression for an RTX for where the
-called function should find the value. If it should find the value on
-the stack, define this to create a @code{mem} which refers to the frame
-pointer. A definition of 0 means that the address is passed as an
-``invisible'' first argument.
-
-@findex PCC_STATIC_STRUCT_RETURN
-@item PCC_STATIC_STRUCT_RETURN
+@defmac PCC_STATIC_STRUCT_RETURN
Define this macro if the usual system convention on the target machine
for returning structures and unions is for the called function to return
the address of a static variable containing the value.
This macro has effect in @option{-fpcc-struct-return} mode, but it does
nothing when you use @option{-freg-struct-return} mode.
-@end table
+@end defmac
@node Caller Saves
@subsection Caller-Saves Register Allocation
makes it possible to use call-clobbered registers to hold variables that
must live across calls.
-@table @code
-@findex DEFAULT_CALLER_SAVES
-@item DEFAULT_CALLER_SAVES
-Define this macro if function calls on the target machine do not preserve
-any registers; in other words, if @code{CALL_USED_REGISTERS} has 1
-for all registers. When defined, this macro enables @option{-fcaller-saves}
-by default for all optimization levels. It has no effect for optimization
-levels 2 and higher, where @option{-fcaller-saves} is the default.
-
-@findex CALLER_SAVE_PROFITABLE
-@item CALLER_SAVE_PROFITABLE (@var{refs}, @var{calls})
+@defmac CALLER_SAVE_PROFITABLE (@var{refs}, @var{calls})
A C expression to determine whether it is worthwhile to consider placing
a pseudo-register in a call-clobbered hard register and saving and
restoring it around each function call. The expression should be 1 when
If you don't define this macro, a default is used which is good on most
machines: @code{4 * @var{calls} < @var{refs}}.
+@end defmac
-@findex HARD_REGNO_CALLER_SAVE_MODE
-@item HARD_REGNO_CALLER_SAVE_MODE (@var{regno}, @var{nregs})
+@defmac HARD_REGNO_CALLER_SAVE_MODE (@var{regno}, @var{nregs})
A C expression specifying which mode is required for saving @var{nregs}
of a pseudo-register in call-clobbered hard register @var{regno}. If
@var{regno} is unsuitable for caller save, @code{VOIDmode} should be
returned. For most machines this macro need not be defined since GCC
will select the smallest suitable mode.
-@end table
+@end defmac
@node Function Entry
@subsection Function Entry and Exit
@c tell? --mew 5feb93
@end deftypefn
-@table @code
-
@itemize @bullet
@item
@findex current_function_pretend_args_size
yet, because the function prologue itself does all the pushing.) This
region is used on machines where an argument may be passed partly in
registers and partly in memory, and, in some cases to support the
-features in @code{<varargs.h>} and @code{<stdarg.h>}.
+features in @code{<stdarg.h>}.
@item
An area of memory used to save certain registers used by the function.
argument lists of the function. @xref{Stack Arguments}.
@end itemize
-Normally, it is necessary for the macros
-@code{TARGET_ASM_FUNCTION_PROLOGUE} and
-@code{TARGET_ASM_FUNCTION_EPILOGUE} to treat leaf functions specially.
-The C variable @code{current_function_is_leaf} is nonzero for such a
-function.
-
-@findex EXIT_IGNORE_STACK
-@item EXIT_IGNORE_STACK
+@defmac EXIT_IGNORE_STACK
Define this macro as a C expression that is nonzero if the return
instruction or the function epilogue ignores the value of the stack
pointer; in other words, if it is safe to delete an instruction to
-adjust the stack pointer before a return from the function.
+adjust the stack pointer before a return from the function. The
+default is 0.
Note that this macro's value is relevant only for functions for which
frame pointers are maintained. It is never safe to delete a final
stack adjustment in a function that has no frame pointer, and the
compiler knows this regardless of @code{EXIT_IGNORE_STACK}.
+@end defmac
-@findex EPILOGUE_USES
-@item EPILOGUE_USES (@var{regno})
+@defmac EPILOGUE_USES (@var{regno})
Define this macro as a C expression that is nonzero for registers that are
used by the epilogue or the @samp{return} pattern. The stack and frame
-pointer registers are already be assumed to be used as needed.
+pointer registers are already assumed to be used as needed.
+@end defmac
-@findex EH_USES
-@item EH_USES (@var{regno})
+@defmac EH_USES (@var{regno})
Define this macro as a C expression that is nonzero for registers that are
used by the exception handling mechanism, and so should be considered live
on entry to an exception edge.
+@end defmac
-@findex DELAY_SLOTS_FOR_EPILOGUE
-@item DELAY_SLOTS_FOR_EPILOGUE
+@defmac DELAY_SLOTS_FOR_EPILOGUE
Define this macro if the function epilogue contains delay slots to which
instructions from the rest of the function can be ``moved''. The
definition should be a C expression whose value is an integer
representing the number of delay slots there.
+@end defmac
-@findex ELIGIBLE_FOR_EPILOGUE_DELAY
-@item ELIGIBLE_FOR_EPILOGUE_DELAY (@var{insn}, @var{n})
+@defmac ELIGIBLE_FOR_EPILOGUE_DELAY (@var{insn}, @var{n})
A C expression that returns 1 if @var{insn} can be placed in delay
slot number @var{n} of the epilogue.
You need not define this macro if you did not define
@code{DELAY_SLOTS_FOR_EPILOGUE}.
+@end defmac
-@findex ASM_OUTPUT_MI_THUNK
-@item ASM_OUTPUT_MI_THUNK (@var{file}, @var{thunk_fndecl}, @var{delta}, @var{function})
-A C compound statement that outputs the assembler code for a thunk
+@deftypefn {Target Hook} void TARGET_ASM_OUTPUT_MI_THUNK (FILE *@var{file}, tree @var{thunk_fndecl}, HOST_WIDE_INT @var{delta}, HOST_WIDE_INT @var{vcall_offset}, tree @var{function})
+A function that outputs the assembler code for a thunk
function, used to implement C++ virtual function calls with multiple
inheritance. The thunk acts as a wrapper around a virtual function,
adjusting the implicit object parameter before handing control off to
e.g.@: @samp{%o0} on a sparc. The addition must preserve the values of
all other incoming arguments.
-After the addition, emit code to jump to @var{function}, which is a
+Then, if @var{vcall_offset} is nonzero, an additional adjustment should be
+made after adding @code{delta}. In particular, if @var{p} is the
+adjusted pointer, the following adjustment should be made:
+
+@smallexample
+p += (*((ptrdiff_t **)p))[vcall_offset/sizeof(ptrdiff_t)]
+@end smallexample
+
+After the additions, emit code to jump to @var{function}, which is a
@code{FUNCTION_DECL}. This is a direct pure jump, not a call, and does
not touch the return address. Hence returning from @var{FUNCTION} will
return to whoever called the current @samp{thunk}.
front end will generate a less efficient heavyweight thunk that calls
@var{function} instead of jumping to it. The generic approach does
not support varargs.
-@end table
+@end deftypefn
+
+@deftypefn {Target Hook} bool TARGET_ASM_CAN_OUTPUT_MI_THUNK (tree @var{thunk_fndecl}, HOST_WIDE_INT @var{delta}, HOST_WIDE_INT @var{vcall_offset}, tree @var{function})
+A function that returns true if TARGET_ASM_OUTPUT_MI_THUNK would be able
+to output the assembler code for the thunk function specified by the
+arguments it is passed, and false otherwise. In the latter case, the
+generic approach will be used by the C++ front end, with the limitations
+previously exposed.
+@end deftypefn
@node Profiling
@subsection Generating Code for Profiling
These macros will help you generate code for profiling.
-@table @code
-@findex FUNCTION_PROFILER
-@item FUNCTION_PROFILER (@var{file}, @var{labelno})
+@defmac FUNCTION_PROFILER (@var{file}, @var{labelno})
A C statement or compound statement to output to @var{file} some
assembler code to call the profiling subroutine @code{mcount}.
variable to be loaded into some register. The name of this variable is
@samp{LP} followed by the number @var{labelno}, so you would generate
the name using @samp{LP%d} in a @code{fprintf}.
+@end defmac
-@findex PROFILE_HOOK
-@item PROFILE_HOOK
+@defmac PROFILE_HOOK
A C statement or compound statement to output to @var{file} some assembly
code to call the profiling subroutine @code{mcount} even the target does
not support profiling.
+@end defmac
-@findex NO_PROFILE_COUNTERS
-@item NO_PROFILE_COUNTERS
-Define this macro if the @code{mcount} subroutine on your system does
-not need a counter variable allocated for each function. This is true
-for almost all modern implementations. If you define this macro, you
-must not use the @var{labelno} argument to @code{FUNCTION_PROFILER}.
+@defmac NO_PROFILE_COUNTERS
+Define this macro to be an expression with a nonzero value if the
+@code{mcount} subroutine on your system does not need a counter variable
+allocated for each function. This is true for almost all modern
+implementations. If you define this macro, you must not use the
+@var{labelno} argument to @code{FUNCTION_PROFILER}.
+@end defmac
-@findex PROFILE_BEFORE_PROLOGUE
-@item PROFILE_BEFORE_PROLOGUE
+@defmac PROFILE_BEFORE_PROLOGUE
Define this macro if the code for function profiling should come before
the function prologue. Normally, the profiling code comes after.
-
-
-@findex TARGET_ALLOWS_PROFILING_WITHOUT_FRAME_POINTER
-@item TARGET_ALLOWS_PROFILING_WITHOUT_FRAME_POINTER
-On some targets, it is impossible to use profiling when the frame
-pointer has been omitted. For example, on x86 GNU/Linux systems,
-the @code{mcount} routine provided by the GNU C Library finds the
-address of the routine that called the routine that called @code{mcount}
-by looking in the immediate caller's stack frame. If the immediate
-caller has no frame pointer, this lookup will fail.
-
-By default, GCC assumes that the target does allow profiling when the
-frame pointer is omitted. This macro should be defined to a C
-expression that evaluates to @code{false} if the target does not allow
-profiling when the frame pointer is omitted.
-
-@end table
+@end defmac
@node Tail Calls
@subsection Permitting tail calls
@cindex tail calls
-@table @code
-@findex FUNCTION_OK_FOR_SIBCALL
-@item FUNCTION_OK_FOR_SIBCALL (@var{decl})
-A C expression that evaluates to true if it is ok to perform a sibling
-call to @var{decl} from the current function.
+@deftypefn {Target Hook} bool TARGET_FUNCTION_OK_FOR_SIBCALL (tree @var{decl}, tree @var{exp})
+True if it is ok to do sibling call optimization for the specified
+call expression @var{exp}. @var{decl} will be the called function,
+or @code{NULL} if this is an indirect call.
It is not uncommon for limitations of calling conventions to prevent
tail calls to functions outside the current unit of translation, or
-during PIC compilation. Use this macro to enforce these restrictions,
+during PIC compilation. The hook is used to enforce these restrictions,
as the @code{sibcall} md pattern can not fail, or fall over to a
-``normal'' call.
-@end table
+``normal'' call. The criteria for successful sibling call optimization
+may vary greatly between different architectures.
+@end deftypefn
+
+@deftypefn {Target Hook} void TARGET_EXTRA_LIVE_ON_ENTRY (bitmap *@var{regs})
+Add any hard registers to @var{regs} that are live on entry to the
+function. This hook only needs to be defined to provide registers that
+cannot be found by examination of FUNCTION_ARG_REGNO_P, the callee saved
+registers, STATIC_CHAIN_INCOMING_REGNUM, STATIC_CHAIN_REGNUM,
+TARGET_STRUCT_VALUE_RTX, FRAME_POINTER_REGNUM, EH_USES,
+FRAME_POINTER_REGNUM, ARG_POINTER_REGNUM, and the PIC_OFFSET_TABLE_REGNUM.
+@end deftypefn
+
+@node Stack Smashing Protection
+@subsection Stack smashing protection
+@cindex stack smashing protection
+
+@deftypefn {Target Hook} tree TARGET_STACK_PROTECT_GUARD (void)
+This hook returns a @code{DECL} node for the external variable to use
+for the stack protection guard. This variable is initialized by the
+runtime to some random value and is used to initialize the guard value
+that is placed at the top of the local stack frame. The type of this
+variable must be @code{ptr_type_node}.
+
+The default version of this hook creates a variable called
+@samp{__stack_chk_guard}, which is normally defined in @file{libgcc2.c}.
+@end deftypefn
+
+@deftypefn {Target Hook} tree TARGET_STACK_PROTECT_FAIL (void)
+This hook returns a tree expression that alerts the runtime that the
+stack protect guard variable has been modified. This expression should
+involve a call to a @code{noreturn} function.
+
+The default version of this hook invokes a function called
+@samp{__stack_chk_fail}, taking no arguments. This function is
+normally defined in @file{libgcc2.c}.
+@end deftypefn
@node Varargs
@section Implementing the Varargs Macros
the end of the named arguments is with the built-in functions described
below.
-@table @code
-@findex __builtin_saveregs
-@item __builtin_saveregs ()
+@defmac __builtin_saveregs ()
Use this built-in function to save the argument registers in memory so
that the varargs mechanism can access them. Both ISO and traditional
versions of @code{va_start} must use @code{__builtin_saveregs}, unless
-you use @code{SETUP_INCOMING_VARARGS} (see below) instead.
+you use @code{TARGET_SETUP_INCOMING_VARARGS} (see below) instead.
On some machines, @code{__builtin_saveregs} is open-coded under the
-control of the macro @code{EXPAND_BUILTIN_SAVEREGS}. On other machines,
-it calls a routine written in assembler language, found in
-@file{libgcc2.c}.
+control of the target hook @code{TARGET_EXPAND_BUILTIN_SAVEREGS}. On
+other machines, it calls a routine written in assembler language,
+found in @file{libgcc2.c}.
Code generated for the call to @code{__builtin_saveregs} appears at the
beginning of the function, as opposed to where the call to
to use them for its own purposes.
@c i rewrote the first sentence above to fix an overfull hbox. --mew
@c 10feb93
+@end defmac
-@findex __builtin_args_info
-@item __builtin_args_info (@var{category})
+@defmac __builtin_args_info (@var{category})
Use this built-in function to find the first anonymous arguments in
registers.
value in the @code{va_list} object. This is because @code{va_list} will
have to update the values, and there is no way to alter the
values accessed by @code{__builtin_args_info}.
+@end defmac
-@findex __builtin_next_arg
-@item __builtin_next_arg (@var{lastarg})
+@defmac __builtin_next_arg (@var{lastarg})
This is the equivalent of @code{__builtin_args_info}, for stack
arguments. It returns the address of the first anonymous stack
argument, as type @code{void *}. If @code{ARGS_GROW_DOWNWARD}, it
fetching arguments from the stack. Also use it in @code{va_start} to
verify that the second parameter @var{lastarg} is the last named argument
of the current function.
+@end defmac
-@findex __builtin_classify_type
-@item __builtin_classify_type (@var{object})
+@defmac __builtin_classify_type (@var{object})
Since each machine has its own conventions for which data types are
passed in which kind of register, your implementation of @code{va_arg}
has to embody these conventions. The easiest way to categorize the
The file @file{typeclass.h} defines an enumeration that you can use to
interpret the values of @code{__builtin_classify_type}.
-@end table
+@end defmac
These machine description macros help implement varargs:
-@table @code
-@findex EXPAND_BUILTIN_SAVEREGS
-@item EXPAND_BUILTIN_SAVEREGS ()
-If defined, is a C expression that produces the machine-specific code
-for a call to @code{__builtin_saveregs}. This code will be moved to the
-very beginning of the function, before any parameter access are made.
-The return value of this function should be an RTX that contains the
-value to use as the return of @code{__builtin_saveregs}.
-
-@findex SETUP_INCOMING_VARARGS
-@item SETUP_INCOMING_VARARGS (@var{args_so_far}, @var{mode}, @var{type}, @var{pretend_args_size}, @var{second_time})
-This macro offers an alternative to using @code{__builtin_saveregs} and
-defining the macro @code{EXPAND_BUILTIN_SAVEREGS}. Use it to store the
-anonymous register arguments into the stack so that all the arguments
-appear to have been passed consecutively on the stack. Once this is
-done, you can use the standard implementation of varargs that works for
-machines that pass all their arguments on the stack.
-
-The argument @var{args_so_far} is the @code{CUMULATIVE_ARGS} data
+@deftypefn {Target Hook} rtx TARGET_EXPAND_BUILTIN_SAVEREGS (void)
+If defined, this hook produces the machine-specific code for a call to
+@code{__builtin_saveregs}. This code will be moved to the very
+beginning of the function, before any parameter access are made. The
+return value of this function should be an RTX that contains the value
+to use as the return of @code{__builtin_saveregs}.
+@end deftypefn
+
+@deftypefn {Target Hook} void TARGET_SETUP_INCOMING_VARARGS (CUMULATIVE_ARGS *@var{args_so_far}, enum machine_mode @var{mode}, tree @var{type}, int *@var{pretend_args_size}, int @var{second_time})
+This target hook offers an alternative to using
+@code{__builtin_saveregs} and defining the hook
+@code{TARGET_EXPAND_BUILTIN_SAVEREGS}. Use it to store the anonymous
+register arguments into the stack so that all the arguments appear to
+have been passed consecutively on the stack. Once this is done, you can
+use the standard implementation of varargs that works for machines that
+pass all their arguments on the stack.
+
+The argument @var{args_so_far} points to the @code{CUMULATIVE_ARGS} data
structure, containing the values that are obtained after processing the
named arguments. The arguments @var{mode} and @var{type} describe the
last named argument---its machine mode and its data type as a tree node.
-The macro implementation should do two things: first, push onto the
-stack all the argument registers @emph{not} used for the named
-arguments, and second, store the size of the data thus pushed into the
-@code{int}-valued variable whose name is supplied as the argument
-@var{pretend_args_size}. The value that you store here will serve as
-additional offset for setting up the stack frame.
+The target hook should do two things: first, push onto the stack all the
+argument registers @emph{not} used for the named arguments, and second,
+store the size of the data thus pushed into the @code{int}-valued
+variable pointed to by @var{pretend_args_size}. The value that you
+store here will serve as additional offset for setting up the stack
+frame.
Because you must generate code to push the anonymous arguments at
compile time without knowing their data types,
-@code{SETUP_INCOMING_VARARGS} is only useful on machines that have just
-a single category of argument register and use it uniformly for all data
-types.
+@code{TARGET_SETUP_INCOMING_VARARGS} is only useful on machines that
+have just a single category of argument register and use it uniformly
+for all data types.
If the argument @var{second_time} is nonzero, it means that the
arguments of the function are being analyzed for the second time. This
happens for an inline function, which is not actually compiled until the
-end of the source file. The macro @code{SETUP_INCOMING_VARARGS} should
+end of the source file. The hook @code{TARGET_SETUP_INCOMING_VARARGS} should
not generate any instructions in this case.
+@end deftypefn
-@findex STRICT_ARGUMENT_NAMING
-@item STRICT_ARGUMENT_NAMING
-Define this macro to be a nonzero value if the location where a function
+@deftypefn {Target Hook} bool TARGET_STRICT_ARGUMENT_NAMING (CUMULATIVE_ARGS *@var{ca})
+Define this hook to return @code{true} if the location where a function
argument is passed depends on whether or not it is a named argument.
-This macro controls how the @var{named} argument to @code{FUNCTION_ARG}
-is set for varargs and stdarg functions. If this macro returns a
-nonzero value, the @var{named} argument is always true for named
-arguments, and false for unnamed arguments. If it returns a value of
-zero, but @code{SETUP_INCOMING_VARARGS} is defined, then all arguments
-are treated as named. Otherwise, all named arguments except the last
-are treated as named.
+This hook controls how the @var{named} argument to @code{FUNCTION_ARG}
+is set for varargs and stdarg functions. If this hook returns
+@code{true}, the @var{named} argument is always true for named
+arguments, and false for unnamed arguments. If it returns @code{false},
+but @code{TARGET_PRETEND_OUTGOING_VARARGS_NAMED} returns @code{true},
+then all arguments are treated as named. Otherwise, all named arguments
+except the last are treated as named.
-You need not define this macro if it always returns zero.
+You need not define this hook if it always returns zero.
+@end deftypefn
-@findex PRETEND_OUTGOING_VARARGS_NAMED
-@item PRETEND_OUTGOING_VARARGS_NAMED
+@deftypefn {Target Hook} bool TARGET_PRETEND_OUTGOING_VARARGS_NAMED
If you need to conditionally change ABIs so that one works with
-@code{SETUP_INCOMING_VARARGS}, but the other works like neither
-@code{SETUP_INCOMING_VARARGS} nor @code{STRICT_ARGUMENT_NAMING} was
-defined, then define this macro to return nonzero if
-@code{SETUP_INCOMING_VARARGS} is used, zero otherwise.
-Otherwise, you should not define this macro.
-@end table
+@code{TARGET_SETUP_INCOMING_VARARGS}, but the other works like neither
+@code{TARGET_SETUP_INCOMING_VARARGS} nor @code{TARGET_STRICT_ARGUMENT_NAMING} was
+defined, then define this hook to return @code{true} if
+@code{TARGET_SETUP_INCOMING_VARARGS} is used, @code{false} otherwise.
+Otherwise, you should not define this hook.
+@end deftypefn
@node Trampolines
@section Trampolines for Nested Functions
may be necessary to take out pieces of the address and store them
separately.
-@table @code
-@findex TRAMPOLINE_TEMPLATE
-@item TRAMPOLINE_TEMPLATE (@var{file})
+@defmac TRAMPOLINE_TEMPLATE (@var{file})
A C statement to output, on the stream @var{file}, assembler code for a
block of data that contains the constant parts of a trampoline. This
code should not include a label---the label is taken care of
for the target. Do not define this macro on systems where the block move
code to copy the trampoline into place would be larger than the code
to generate it on the spot.
+@end defmac
-@findex TRAMPOLINE_SECTION
-@item TRAMPOLINE_SECTION
-The name of a subroutine to switch to the section in which the
-trampoline template is to be placed (@pxref{Sections}). The default is
-a value of @samp{readonly_data_section}, which places the trampoline in
-the section containing read-only data.
+@defmac TRAMPOLINE_SECTION
+Return the section into which the trampoline template is to be placed
+(@pxref{Sections}). The default value is @code{readonly_data_section}.
+@end defmac
-@findex TRAMPOLINE_SIZE
-@item TRAMPOLINE_SIZE
+@defmac TRAMPOLINE_SIZE
A C expression for the size in bytes of the trampoline, as an integer.
+@end defmac
-@findex TRAMPOLINE_ALIGNMENT
-@item TRAMPOLINE_ALIGNMENT
+@defmac TRAMPOLINE_ALIGNMENT
Alignment required for trampolines, in bits.
If you don't define this macro, the value of @code{BIGGEST_ALIGNMENT}
is used for aligning trampolines.
+@end defmac
-@findex INITIALIZE_TRAMPOLINE
-@item INITIALIZE_TRAMPOLINE (@var{addr}, @var{fnaddr}, @var{static_chain})
+@defmac INITIALIZE_TRAMPOLINE (@var{addr}, @var{fnaddr}, @var{static_chain})
A C statement to initialize the variable parts of a trampoline.
@var{addr} is an RTX for the address of the trampoline; @var{fnaddr} is
an RTX for the address of the nested function; @var{static_chain} is an
RTX for the static chain value that should be passed to the function
when it is called.
+@end defmac
-@findex TRAMPOLINE_ADJUST_ADDRESS
-@item TRAMPOLINE_ADJUST_ADDRESS (@var{addr})
+@defmac TRAMPOLINE_ADJUST_ADDRESS (@var{addr})
A C statement that should perform any machine-specific adjustment in
the address of the trampoline. Its argument contains the address that
was passed to @code{INITIALIZE_TRAMPOLINE}. In case the address to be
@var{addr}. If this macro is not defined, @var{addr} will be used for
function calls.
-@findex ALLOCATE_TRAMPOLINE
-@item ALLOCATE_TRAMPOLINE (@var{fp})
-A C expression to allocate run-time space for a trampoline. The
-expression value should be an RTX representing a memory reference to the
-space for the trampoline.
-
@cindex @code{TARGET_ASM_FUNCTION_EPILOGUE} and trampolines
@cindex @code{TARGET_ASM_FUNCTION_PROLOGUE} and trampolines
If this macro is not defined, by default the trampoline is allocated as
@var{fp} points to a data structure, a @code{struct function}, which
describes the compilation status of the immediate containing function of
-the function which the trampoline is for. Normally (when
-@code{ALLOCATE_TRAMPOLINE} is not defined), the stack slot for the
+the function which the trampoline is for. The stack slot for the
trampoline is in the stack frame of this containing function. Other
allocation strategies probably must do something analogous with this
information.
-@end table
+@end defmac
Implementing trampolines is difficult on many machines because they have
separate instruction and data caches. Writing into a stack location
latter makes initialization faster.
To clear the instruction cache when a trampoline is initialized, define
-the following macros which describe the shape of the cache.
-
-@table @code
-@findex INSN_CACHE_SIZE
-@item INSN_CACHE_SIZE
-The total size in bytes of the cache.
-
-@findex INSN_CACHE_LINE_WIDTH
-@item INSN_CACHE_LINE_WIDTH
-The length in bytes of each cache line. The cache is divided into cache
-lines which are disjoint slots, each holding a contiguous chunk of data
-fetched from memory. Each time data is brought into the cache, an
-entire line is read at once. The data loaded into a cache line is
-always aligned on a boundary equal to the line size.
-
-@findex INSN_CACHE_DEPTH
-@item INSN_CACHE_DEPTH
-The number of alternative cache lines that can hold any particular memory
-location.
-@end table
-
-Alternatively, if the machine has system calls or instructions to clear
-the instruction cache directly, you can define the following macro.
+the following macro.
-@table @code
-@findex CLEAR_INSN_CACHE
-@item CLEAR_INSN_CACHE (@var{beg}, @var{end})
+@defmac CLEAR_INSN_CACHE (@var{beg}, @var{end})
If defined, expands to a C expression clearing the @emph{instruction
-cache} in the specified interval. If it is not defined, and the macro
-@code{INSN_CACHE_SIZE} is defined, some generic code is generated to clear the
-cache. The definition of this macro would typically be a series of
-@code{asm} statements. Both @var{beg} and @var{end} are both pointer
-expressions.
-@end table
+cache} in the specified interval. The definition of this macro would
+typically be a series of @code{asm} statements. Both @var{beg} and
+@var{end} are both pointer expressions.
+@end defmac
+
+The operating system may also require the stack to be made executable
+before calling the trampoline. To implement this requirement, define
+the following macro.
+
+@defmac ENABLE_EXECUTE_STACK
+Define this macro if certain operations must be performed before executing
+code located on the stack. The macro should expand to a series of C
+file-scope constructs (e.g.@: functions) and provide a unique entry point
+named @code{__enable_execute_stack}. The target is responsible for
+emitting calls to the entry point in the code, for example from the
+@code{INITIALIZE_TRAMPOLINE} macro.
+@end defmac
To use a standard subroutine, define the following macro. In addition,
you must make sure that the instructions in a trampoline fill an entire
beginning of the trampoline code is always aligned at the same point in
its cache line. Look in @file{m68k.h} as a guide.
-@table @code
-@findex TRANSFER_FROM_TRAMPOLINE
-@item TRANSFER_FROM_TRAMPOLINE
+@defmac TRANSFER_FROM_TRAMPOLINE
Define this macro if trampolines need a special subroutine to do their
work. The macro should expand to a series of @code{asm} statements
which will be compiled with GCC@. They go in a library function named
statement to generate an assembler label, and another to make the label
global. Then trampolines can use that label to jump directly to your
special assembler code.
-@end table
+@end defmac
@node Library Calls
@section Implicit Calls to Library Routines
@c prevent bad page break with this line
Here is an explanation of implicit calls to library routines.
-@table @code
-@findex MULSI3_LIBCALL
-@item MULSI3_LIBCALL
-A C string constant giving the name of the function to call for
-multiplication of one signed full-word by another. If you do not
-define this macro, the default name is used, which is @code{__mulsi3},
-a function defined in @file{libgcc.a}.
-
-@findex DIVSI3_LIBCALL
-@item DIVSI3_LIBCALL
-A C string constant giving the name of the function to call for
-division of one signed full-word by another. If you do not define
-this macro, the default name is used, which is @code{__divsi3}, a
-function defined in @file{libgcc.a}.
-
-@findex UDIVSI3_LIBCALL
-@item UDIVSI3_LIBCALL
-A C string constant giving the name of the function to call for
-division of one unsigned full-word by another. If you do not define
-this macro, the default name is used, which is @code{__udivsi3}, a
-function defined in @file{libgcc.a}.
-
-@findex MODSI3_LIBCALL
-@item MODSI3_LIBCALL
-A C string constant giving the name of the function to call for the
-remainder in division of one signed full-word by another. If you do
-not define this macro, the default name is used, which is
-@code{__modsi3}, a function defined in @file{libgcc.a}.
-
-@findex UMODSI3_LIBCALL
-@item UMODSI3_LIBCALL
-A C string constant giving the name of the function to call for the
-remainder in division of one unsigned full-word by another. If you do
-not define this macro, the default name is used, which is
-@code{__umodsi3}, a function defined in @file{libgcc.a}.
-
-@findex MULDI3_LIBCALL
-@item MULDI3_LIBCALL
-A C string constant giving the name of the function to call for
-multiplication of one signed double-word by another. If you do not
-define this macro, the default name is used, which is @code{__muldi3},
-a function defined in @file{libgcc.a}.
-
-@findex DIVDI3_LIBCALL
-@item DIVDI3_LIBCALL
-A C string constant giving the name of the function to call for
-division of one signed double-word by another. If you do not define
-this macro, the default name is used, which is @code{__divdi3}, a
-function defined in @file{libgcc.a}.
-
-@findex UDIVDI3_LIBCALL
-@item UDIVDI3_LIBCALL
-A C string constant giving the name of the function to call for
-division of one unsigned full-word by another. If you do not define
-this macro, the default name is used, which is @code{__udivdi3}, a
-function defined in @file{libgcc.a}.
-
-@findex MODDI3_LIBCALL
-@item MODDI3_LIBCALL
-A C string constant giving the name of the function to call for the
-remainder in division of one signed double-word by another. If you do
-not define this macro, the default name is used, which is
-@code{__moddi3}, a function defined in @file{libgcc.a}.
-
-@findex UMODDI3_LIBCALL
-@item UMODDI3_LIBCALL
-A C string constant giving the name of the function to call for the
-remainder in division of one unsigned full-word by another. If you do
-not define this macro, the default name is used, which is
-@code{__umoddi3}, a function defined in @file{libgcc.a}.
-
-@findex INIT_TARGET_OPTABS
-@item INIT_TARGET_OPTABS
-Define this macro as a C statement that declares additional library
-routines renames existing ones. @code{init_optabs} calls this macro after
-initializing all the normal library routines.
-
-@findex FLOAT_LIB_COMPARE_RETURNS_BOOL (@var{mode}, @var{comparison})
-@item FLOAT_LIB_COMPARE_RETURNS_BOOL
-Define this macro as a C statement that returns nonzero if a call to
-the floating point comparison library function will return a boolean
-value that indicates the result of the comparison. It should return
-zero if one of gcc's own libgcc functions is called.
-
-Most ports don't need to define this macro.
-
-@findex TARGET_EDOM
+@defmac DECLARE_LIBRARY_RENAMES
+This macro, if defined, should expand to a piece of C code that will get
+expanded when compiling functions for libgcc.a. It can be used to
+provide alternate names for GCC's internal library functions if there
+are ABI-mandated names that the compiler should provide.
+@end defmac
+
+@findex init_one_libfunc
+@findex set_optab_libfunc
+@deftypefn {Target Hook} void TARGET_INIT_LIBFUNCS (void)
+This hook should declare additional library routines or rename
+existing ones, using the functions @code{set_optab_libfunc} and
+@code{init_one_libfunc} defined in @file{optabs.c}.
+@code{init_optabs} calls this macro after initializing all the normal
+library routines.
+
+The default is to do nothing. Most ports don't need to define this hook.
+@end deftypefn
+
+@defmac FLOAT_LIB_COMPARE_RETURNS_BOOL (@var{mode}, @var{comparison})
+This macro should return @code{true} if the library routine that
+implements the floating point comparison operator @var{comparison} in
+mode @var{mode} will return a boolean, and @var{false} if it will
+return a tristate.
+
+GCC's own floating point libraries return tristates from the
+comparison operators, so the default returns false always. Most ports
+don't need to define this macro.
+@end defmac
+
+@defmac TARGET_LIB_INT_CMP_BIASED
+This macro should evaluate to @code{true} if the integer comparison
+functions (like @code{__cmpdi2}) return 0 to indicate that the first
+operand is smaller than the second, 1 to indicate that they are equal,
+and 2 to indicate that the first operand is greater than the second.
+If this macro evaluates to @code{false} the comparison functions return
+@minus{}1, 0, and 1 instead of 0, 1, and 2. If the target uses the routines
+in @file{libgcc.a}, you do not need to define this macro.
+@end defmac
+
+@cindex US Software GOFAST, floating point emulation library
+@cindex floating point emulation library, US Software GOFAST
+@cindex GOFAST, floating point emulation library
+@findex gofast_maybe_init_libfuncs
+@defmac US_SOFTWARE_GOFAST
+Define this macro if your system C library uses the US Software GOFAST
+library to provide floating point emulation.
+
+In addition to defining this macro, your architecture must set
+@code{TARGET_INIT_LIBFUNCS} to @code{gofast_maybe_init_libfuncs}, or
+else call that function from its version of that hook. It is defined
+in @file{config/gofast.h}, which must be included by your
+architecture's @file{@var{cpu}.c} file. See @file{sparc/sparc.c} for
+an example.
+
+If this macro is defined, the
+@code{TARGET_FLOAT_LIB_COMPARE_RETURNS_BOOL} target hook must return
+false for @code{SFmode} and @code{DFmode} comparisons.
+@end defmac
+
@cindex @code{EDOM}, implicit usage
-@item TARGET_EDOM
+@findex matherr
+@defmac TARGET_EDOM
The value of @code{EDOM} on the target machine, as a C integer constant
expression. If you don't define this macro, GCC does not attempt to
deposit the value of @code{EDOM} into @code{errno} directly. Look in
error. If mathematical functions on your system use @code{matherr} when
there is an error, then you should leave @code{TARGET_EDOM} undefined so
that @code{matherr} is used normally.
+@end defmac
-@findex GEN_ERRNO_RTX
@cindex @code{errno}, implicit usage
-@item GEN_ERRNO_RTX
+@defmac GEN_ERRNO_RTX
Define this macro as a C expression to create an rtl expression that
refers to the global ``variable'' @code{errno}. (On certain systems,
@code{errno} may not actually be a variable.) If you don't define this
macro, a reasonable default is used.
+@end defmac
+
+@cindex C99 math functions, implicit usage
+@defmac TARGET_C99_FUNCTIONS
+When this macro is nonzero, GCC will implicitly optimize @code{sin} calls into
+@code{sinf} and similarly for other functions defined by C99 standard. The
+default is zero because a number of existing systems lack support for these
+functions in their runtime so this macro needs to be redefined to one on
+systems that do support the C99 runtime.
+@end defmac
+
+@cindex sincos math function, implicit usage
+@defmac TARGET_HAS_SINCOS
+When this macro is nonzero, GCC will implicitly optimize calls to @code{sin}
+and @code{cos} with the same argument to a call to @code{sincos}. The
+default is zero. The target has to provide the following functions:
+@smallexample
+void sincos(double x, double *sin, double *cos);
+void sincosf(float x, float *sin, float *cos);
+void sincosl(long double x, long double *sin, long double *cos);
+@end smallexample
+@end defmac
-@findex TARGET_MEM_FUNCTIONS
-@cindex @code{bcopy}, implicit usage
-@cindex @code{memcpy}, implicit usage
-@cindex @code{memmove}, implicit usage
-@cindex @code{bzero}, implicit usage
-@cindex @code{memset}, implicit usage
-@item TARGET_MEM_FUNCTIONS
-Define this macro if GCC should generate calls to the ISO C
-(and System V) library functions @code{memcpy}, @code{memmove} and
-@code{memset} rather than the BSD functions @code{bcopy} and @code{bzero}.
-
-@findex LIBGCC_NEEDS_DOUBLE
-@item LIBGCC_NEEDS_DOUBLE
-Define this macro if @code{float} arguments cannot be passed to library
-routines (so they must be converted to @code{double}). This macro
-affects both how library calls are generated and how the library
-routines in @file{libgcc.a} accept their arguments. It is useful on
-machines where floating and fixed point arguments are passed
-differently, such as the i860.
-
-@findex NEXT_OBJC_RUNTIME
-@item NEXT_OBJC_RUNTIME
+@defmac NEXT_OBJC_RUNTIME
Define this macro to generate code for Objective-C message sending using
the calling convention of the NeXT system. This calling convention
involves passing the object, the selector and the method arguments all
The default calling convention passes just the object and the selector
to the lookup function, which returns a pointer to the method.
-@end table
+@end defmac
@node Addressing Modes
@section Addressing Modes
@c prevent bad page break with this line
This is about addressing modes.
-@table @code
-@findex HAVE_PRE_INCREMENT
-@findex HAVE_PRE_DECREMENT
-@findex HAVE_POST_INCREMENT
-@findex HAVE_POST_DECREMENT
-@item HAVE_PRE_INCREMENT
-@itemx HAVE_PRE_DECREMENT
-@itemx HAVE_POST_INCREMENT
-@itemx HAVE_POST_DECREMENT
+@defmac HAVE_PRE_INCREMENT
+@defmacx HAVE_PRE_DECREMENT
+@defmacx HAVE_POST_INCREMENT
+@defmacx HAVE_POST_DECREMENT
A C expression that is nonzero if the machine supports pre-increment,
pre-decrement, post-increment, or post-decrement addressing respectively.
+@end defmac
-@findex HAVE_POST_MODIFY_DISP
-@findex HAVE_PRE_MODIFY_DISP
-@item HAVE_PRE_MODIFY_DISP
-@itemx HAVE_POST_MODIFY_DISP
+@defmac HAVE_PRE_MODIFY_DISP
+@defmacx HAVE_POST_MODIFY_DISP
A C expression that is nonzero if the machine supports pre- or
post-address side-effect generation involving constants other than
the size of the memory operand.
+@end defmac
-@findex HAVE_POST_MODIFY_REG
-@findex HAVE_PRE_MODIFY_REG
-@item HAVE_PRE_MODIFY_REG
-@itemx HAVE_POST_MODIFY_REG
+@defmac HAVE_PRE_MODIFY_REG
+@defmacx HAVE_POST_MODIFY_REG
A C expression that is nonzero if the machine supports pre- or
post-address side-effect generation involving a register displacement.
+@end defmac
-@findex CONSTANT_ADDRESS_P
-@item CONSTANT_ADDRESS_P (@var{x})
+@defmac CONSTANT_ADDRESS_P (@var{x})
A C expression that is 1 if the RTX @var{x} is a constant which
is a valid address. On most machines, this can be defined as
@code{CONSTANT_P (@var{x})}, but a few machines are more restrictive
in which constant addresses are supported.
+@end defmac
-@findex CONSTANT_P
-@code{CONSTANT_P} accepts integer-values expressions whose values are
-not explicitly known, such as @code{symbol_ref}, @code{label_ref}, and
-@code{high} expressions and @code{const} arithmetic expressions, in
-addition to @code{const_int} and @code{const_double} expressions.
+@defmac CONSTANT_P (@var{x})
+@code{CONSTANT_P}, which is defined by target-independent code,
+accepts integer-values expressions whose values are not explicitly
+known, such as @code{symbol_ref}, @code{label_ref}, and @code{high}
+expressions and @code{const} arithmetic expressions, in addition to
+@code{const_int} and @code{const_double} expressions.
+@end defmac
-@findex MAX_REGS_PER_ADDRESS
-@item MAX_REGS_PER_ADDRESS
+@defmac MAX_REGS_PER_ADDRESS
A number, the maximum number of registers that can appear in a valid
memory address. Note that it is up to you to specify a value equal to
the maximum number that @code{GO_IF_LEGITIMATE_ADDRESS} would ever
accept.
+@end defmac
-@findex GO_IF_LEGITIMATE_ADDRESS
-@item GO_IF_LEGITIMATE_ADDRESS (@var{mode}, @var{x}, @var{label})
+@defmac GO_IF_LEGITIMATE_ADDRESS (@var{mode}, @var{x}, @var{label})
A C compound statement with a conditional @code{goto @var{label};}
executed if @var{x} (an RTX) is a legitimate memory address on the
target machine for a memory operand of mode @var{mode}.
naked constant sums as illegitimate addresses, so that none of them will
be given to @code{PRINT_OPERAND_ADDRESS}.
-@cindex @code{ENCODE_SECTION_INFO} and address validation
+@cindex @code{TARGET_ENCODE_SECTION_INFO} and address validation
On some machines, whether a symbolic address is legitimate depends on
the section that the address refers to. On these machines, define the
-macro @code{ENCODE_SECTION_INFO} to store the information into the
-@code{symbol_ref}, and then check for it here. When you see a
+target hook @code{TARGET_ENCODE_SECTION_INFO} to store the information
+into the @code{symbol_ref}, and then check for it here. When you see a
@code{const}, you will have to look inside it to find the
@code{symbol_ref} in order to determine the section. @xref{Assembler
Format}.
-
-@findex saveable_obstack
-The best way to modify the name string is by adding text to the
-beginning, with suitable punctuation to prevent any ambiguity. Allocate
-the new name in @code{saveable_obstack}. You will have to modify
-@code{ASM_OUTPUT_LABELREF} to remove and decode the added text and
-output the name accordingly, and define @code{STRIP_NAME_ENCODING} to
-access the original name string.
-
-You can check the information stored here into the @code{symbol_ref} in
-the definitions of the macros @code{GO_IF_LEGITIMATE_ADDRESS} and
-@code{PRINT_OPERAND_ADDRESS}.
-
-@findex REG_OK_FOR_BASE_P
-@item REG_OK_FOR_BASE_P (@var{x})
-A C expression that is nonzero if @var{x} (assumed to be a @code{reg}
-RTX) is valid for use as a base register. For hard registers, it
-should always accept those which the hardware permits and reject the
-others. Whether the macro accepts or rejects pseudo registers must be
-controlled by @code{REG_OK_STRICT} as described above. This usually
-requires two variant definitions, of which @code{REG_OK_STRICT}
-controls the one actually used.
-
-@findex REG_MODE_OK_FOR_BASE_P
-@item REG_MODE_OK_FOR_BASE_P (@var{x}, @var{mode})
-A C expression that is just like @code{REG_OK_FOR_BASE_P}, except that
-that expression may examine the mode of the memory reference in
-@var{mode}. You should define this macro if the mode of the memory
-reference affects whether a register may be used as a base register. If
-you define this macro, the compiler will use it instead of
-@code{REG_OK_FOR_BASE_P}.
-
-@findex REG_OK_FOR_INDEX_P
-@item REG_OK_FOR_INDEX_P (@var{x})
-A C expression that is nonzero if @var{x} (assumed to be a @code{reg}
-RTX) is valid for use as an index register.
-
-The difference between an index register and a base register is that
-the index register may be scaled. If an address involves the sum of
-two registers, neither one of them scaled, then either one may be
-labeled the ``base'' and the other the ``index''; but whichever
-labeling is used must fit the machine's constraints of which registers
-may serve in each capacity. The compiler will try both labelings,
-looking for one that is valid, and will reload one or both registers
-only if neither labeling works.
-
-@findex FIND_BASE_TERM
-@item FIND_BASE_TERM (@var{x})
-A C expression to determine the base term of address @var{x}.
-This macro is used in only one place: `find_base_term' in alias.c.
+@end defmac
+
+@defmac TARGET_MEM_CONSTRAINT
+A single character to be used instead of the default @code{'m'}
+character for general memory addresses. This defines the constraint
+letter which matches the memory addresses accepted by
+@code{GO_IF_LEGITIMATE_ADDRESS_P}. Define this macro if you want to
+support new address formats in your back end without changing the
+semantics of the @code{'m'} constraint. This is necessary in order to
+preserve functionality of inline assembly constructs using the
+@code{'m'} constraint.
+@end defmac
+
+@defmac FIND_BASE_TERM (@var{x})
+A C expression to determine the base term of address @var{x},
+or to provide a simplified version of @var{x} from which @file{alias.c}
+can easily find the base term. This macro is used in only two places:
+@code{find_base_value} and @code{find_base_term} in @file{alias.c}.
It is always safe for this macro to not be defined. It exists so
that alias analysis can understand machine-dependent addresses.
The typical use of this macro is to handle addresses containing
a label_ref or symbol_ref within an UNSPEC@.
+@end defmac
-@findex LEGITIMIZE_ADDRESS
-@item LEGITIMIZE_ADDRESS (@var{x}, @var{oldx}, @var{mode}, @var{win})
+@defmac LEGITIMIZE_ADDRESS (@var{x}, @var{oldx}, @var{mode}, @var{win})
A C compound statement that attempts to replace @var{x} with a valid
memory address for an operand of mode @var{mode}. @var{win} will be a
C statement label elsewhere in the code; the macro definition may use
-@example
+@smallexample
GO_IF_LEGITIMATE_ADDRESS (@var{mode}, @var{x}, @var{win});
-@end example
+@end smallexample
@noindent
to avoid further processing if the address has become legitimate.
It is not necessary for this macro to come up with a legitimate
address. The compiler has standard ways of doing so in all cases. In
-fact, it is safe for this macro to do nothing. But often a
+fact, it is safe to omit this macro. But often a
machine-dependent strategy can generate better code.
+@end defmac
-@findex LEGITIMIZE_RELOAD_ADDRESS
-@item LEGITIMIZE_RELOAD_ADDRESS (@var{x}, @var{mode}, @var{opnum}, @var{type}, @var{ind_levels}, @var{win})
+@defmac LEGITIMIZE_RELOAD_ADDRESS (@var{x}, @var{mode}, @var{opnum}, @var{type}, @var{ind_levels}, @var{win})
A C compound statement that attempts to replace @var{x}, which is an address
that needs reloading, with a valid memory address for an operand of mode
@var{mode}. @var{win} will be a C statement label elsewhere in the code.
@findex copy_rtx
If you want to change only a part of @var{x}, one standard way of doing
-this is to use @code{copy_rtx}. Note, however, that is unshares only a
+this is to use @code{copy_rtx}. Note, however, that it unshares only a
single level of rtl. Thus, if the part to be changed is not at the
top level, you'll need to replace first the top level.
It is not necessary for this macro to come up with a legitimate
address; but often a machine-dependent strategy can generate better code.
+@end defmac
-@findex GO_IF_MODE_DEPENDENT_ADDRESS
-@item GO_IF_MODE_DEPENDENT_ADDRESS (@var{addr}, @var{label})
+@defmac GO_IF_MODE_DEPENDENT_ADDRESS (@var{addr}, @var{label})
A C statement or compound statement with a conditional @code{goto
@var{label};} executed if memory address @var{x} (an RTX) can have
different meanings depending on the machine mode of the memory
addresses. Many RISC machines have no mode-dependent addresses.
You may assume that @var{addr} is a valid address for the machine.
+@end defmac
-@findex LEGITIMATE_CONSTANT_P
-@item LEGITIMATE_CONSTANT_P (@var{x})
+@defmac LEGITIMATE_CONSTANT_P (@var{x})
A C expression that is nonzero if @var{x} is a legitimate constant for
an immediate operand on the target machine. You can assume that
@var{x} satisfies @code{CONSTANT_P}, so you need not check this. In fact,
@samp{1} is a suitable definition for this macro on machines where
anything @code{CONSTANT_P} is valid.
-@end table
+@end defmac
+
+@deftypefn {Target Hook} rtx TARGET_DELEGITIMIZE_ADDRESS (rtx @var{x})
+This hook is used to undo the possibly obfuscating effects of the
+@code{LEGITIMIZE_ADDRESS} and @code{LEGITIMIZE_RELOAD_ADDRESS} target
+macros. Some backend implementations of these macros wrap symbol
+references inside an @code{UNSPEC} rtx to represent PIC or similar
+addressing modes. This target hook allows GCC's optimizers to understand
+the semantics of these opaque @code{UNSPEC}s by converting them back
+into their original form.
+@end deftypefn
+
+@deftypefn {Target Hook} bool TARGET_CANNOT_FORCE_CONST_MEM (rtx @var{x})
+This hook should return true if @var{x} is of a form that cannot (or
+should not) be spilled to the constant pool. The default version of
+this hook returns false.
+
+The primary reason to define this hook is to prevent reload from
+deciding that a non-legitimate constant would be better reloaded
+from the constant pool instead of spilling and reloading a register
+holding the constant. This restriction is often true of addresses
+of TLS symbols for various targets.
+@end deftypefn
+
+@deftypefn {Target Hook} bool TARGET_USE_BLOCKS_FOR_CONSTANT_P (enum machine_mode @var{mode}, rtx @var{x})
+This hook should return true if pool entries for constant @var{x} can
+be placed in an @code{object_block} structure. @var{mode} is the mode
+of @var{x}.
+
+The default version returns false for all constants.
+@end deftypefn
+
+@deftypefn {Target Hook} tree TARGET_BUILTIN_RECIPROCAL (enum tree_code @var{fn}, bool @var{tm_fn}, bool @var{sqrt})
+This hook should return the DECL of a function that implements reciprocal of
+the builtin function with builtin function code @var{fn}, or
+@code{NULL_TREE} if such a function is not available. @var{tm_fn} is true
+when @var{fn} is a code of a machine-dependent builtin function. When
+@var{sqrt} is true, additional optimizations that apply only to the reciprocal
+of a square root function are performed, and only reciprocals of @code{sqrt}
+function are valid.
+@end deftypefn
+
+@deftypefn {Target Hook} tree TARGET_VECTORIZE_BUILTIN_MASK_FOR_LOAD (void)
+This hook should return the DECL of a function @var{f} that given an
+address @var{addr} as an argument returns a mask @var{m} that can be
+used to extract from two vectors the relevant data that resides in
+@var{addr} in case @var{addr} is not properly aligned.
+
+The autovectorizer, when vectorizing a load operation from an address
+@var{addr} that may be unaligned, will generate two vector loads from
+the two aligned addresses around @var{addr}. It then generates a
+@code{REALIGN_LOAD} operation to extract the relevant data from the
+two loaded vectors. The first two arguments to @code{REALIGN_LOAD},
+@var{v1} and @var{v2}, are the two vectors, each of size @var{VS}, and
+the third argument, @var{OFF}, defines how the data will be extracted
+from these two vectors: if @var{OFF} is 0, then the returned vector is
+@var{v2}; otherwise, the returned vector is composed from the last
+@var{VS}-@var{OFF} elements of @var{v1} concatenated to the first
+@var{OFF} elements of @var{v2}.
+
+If this hook is defined, the autovectorizer will generate a call
+to @var{f} (using the DECL tree that this hook returns) and will
+use the return value of @var{f} as the argument @var{OFF} to
+@code{REALIGN_LOAD}. Therefore, the mask @var{m} returned by @var{f}
+should comply with the semantics expected by @code{REALIGN_LOAD}
+described above.
+If this hook is not defined, then @var{addr} will be used as
+the argument @var{OFF} to @code{REALIGN_LOAD}, in which case the low
+log2(@var{VS})-1 bits of @var{addr} will be considered.
+@end deftypefn
+
+@deftypefn {Target Hook} tree TARGET_VECTORIZE_BUILTIN_MUL_WIDEN_EVEN (tree @var{x})
+This hook should return the DECL of a function @var{f} that implements
+widening multiplication of the even elements of two input vectors of type @var{x}.
+
+If this hook is defined, the autovectorizer will use it along with the
+@code{TARGET_VECTORIZE_BUILTIN_MUL_WIDEN_ODD} target hook when vectorizing
+widening multiplication in cases that the order of the results does not have to be
+preserved (e.g.@: used only by a reduction computation). Otherwise, the
+@code{widen_mult_hi/lo} idioms will be used.
+@end deftypefn
+
+@deftypefn {Target Hook} tree TARGET_VECTORIZE_BUILTIN_MUL_WIDEN_ODD (tree @var{x})
+This hook should return the DECL of a function @var{f} that implements
+widening multiplication of the odd elements of two input vectors of type @var{x}.
+
+If this hook is defined, the autovectorizer will use it along with the
+@code{TARGET_VECTORIZE_BUILTIN_MUL_WIDEN_EVEN} target hook when vectorizing
+widening multiplication in cases that the order of the results does not have to be
+preserved (e.g.@: used only by a reduction computation). Otherwise, the
+@code{widen_mult_hi/lo} idioms will be used.
+@end deftypefn
+
+@deftypefn {Target Hook} tree TARGET_VECTORIZE_BUILTIN_CONVERSION (enum tree_code @var{code}, tree @var{type})
+This hook should return the DECL of a function that implements conversion of the
+input vector of type @var{type}.
+If @var{type} is an integral type, the result of the conversion is a vector of
+floating-point type of the same size.
+If @var{type} is a floating-point type, the result of the conversion is a vector
+of integral type of the same size.
+@var{code} specifies how the conversion is to be applied
+(truncation, rounding, etc.).
+
+If this hook is defined, the autovectorizer will use the
+@code{TARGET_VECTORIZE_BUILTIN_CONVERSION} target hook when vectorizing
+conversion. Otherwise, it will return @code{NULL_TREE}.
+@end deftypefn
+
+@deftypefn {Target Hook} tree TARGET_VECTORIZE_BUILTIN_VECTORIZED_FUNCTION (enum built_in_function @var{code}, tree @var{vec_type_out}, tree @var{vec_type_in})
+This hook should return the decl of a function that implements the vectorized
+variant of the builtin function with builtin function code @var{code} or
+@code{NULL_TREE} if such a function is not available. The return type of
+the vectorized function shall be of vector type @var{vec_type_out} and the
+argument types should be @var{vec_type_in}.
+@end deftypefn
+
+@node Anchored Addresses
+@section Anchored Addresses
+@cindex anchored addresses
+@cindex @option{-fsection-anchors}
+
+GCC usually addresses every static object as a separate entity.
+For example, if we have:
+
+@smallexample
+static int a, b, c;
+int foo (void) @{ return a + b + c; @}
+@end smallexample
+
+the code for @code{foo} will usually calculate three separate symbolic
+addresses: those of @code{a}, @code{b} and @code{c}. On some targets,
+it would be better to calculate just one symbolic address and access
+the three variables relative to it. The equivalent pseudocode would
+be something like:
+
+@smallexample
+int foo (void)
+@{
+ register int *xr = &x;
+ return xr[&a - &x] + xr[&b - &x] + xr[&c - &x];
+@}
+@end smallexample
+
+(which isn't valid C). We refer to shared addresses like @code{x} as
+``section anchors''. Their use is controlled by @option{-fsection-anchors}.
+
+The hooks below describe the target properties that GCC needs to know
+in order to make effective use of section anchors. It won't use
+section anchors at all unless either @code{TARGET_MIN_ANCHOR_OFFSET}
+or @code{TARGET_MAX_ANCHOR_OFFSET} is set to a nonzero value.
+
+@deftypevar {Target Hook} HOST_WIDE_INT TARGET_MIN_ANCHOR_OFFSET
+The minimum offset that should be applied to a section anchor.
+On most targets, it should be the smallest offset that can be
+applied to a base register while still giving a legitimate address
+for every mode. The default value is 0.
+@end deftypevar
+
+@deftypevar {Target Hook} HOST_WIDE_INT TARGET_MAX_ANCHOR_OFFSET
+Like @code{TARGET_MIN_ANCHOR_OFFSET}, but the maximum (inclusive)
+offset that should be applied to section anchors. The default
+value is 0.
+@end deftypevar
+
+@deftypefn {Target Hook} void TARGET_ASM_OUTPUT_ANCHOR (rtx @var{x})
+Write the assembly code to define section anchor @var{x}, which is a
+@code{SYMBOL_REF} for which @samp{SYMBOL_REF_ANCHOR_P (@var{x})} is true.
+The hook is called with the assembly output position set to the beginning
+of @code{SYMBOL_REF_BLOCK (@var{x})}.
+
+If @code{ASM_OUTPUT_DEF} is available, the hook's default definition uses
+it to define the symbol as @samp{. + SYMBOL_REF_BLOCK_OFFSET (@var{x})}.
+If @code{ASM_OUTPUT_DEF} is not available, the hook's default definition
+is @code{NULL}, which disables the use of section anchors altogether.
+@end deftypefn
+
+@deftypefn {Target Hook} bool TARGET_USE_ANCHORS_FOR_SYMBOL_P (rtx @var{x})
+Return true if GCC should attempt to use anchors to access @code{SYMBOL_REF}
+@var{x}. You can assume @samp{SYMBOL_REF_HAS_BLOCK_INFO_P (@var{x})} and
+@samp{!SYMBOL_REF_ANCHOR_P (@var{x})}.
+
+The default version is correct for most targets, but you might need to
+intercept this hook to handle things like target-specific attributes
+or target-specific sections.
+@end deftypefn
@node Condition Code
@section Condition Code Status
description header file. It can also add additional machine-specific
information by defining @code{CC_STATUS_MDEP}.
-@table @code
-@findex CC_STATUS_MDEP
-@item CC_STATUS_MDEP
+@defmac CC_STATUS_MDEP
C code for a data type which is used for declaring the @code{mdep}
component of @code{cc_status}. It defaults to @code{int}.
This macro is not used on machines that do not use @code{cc0}.
+@end defmac
-@findex CC_STATUS_MDEP_INIT
-@item CC_STATUS_MDEP_INIT
+@defmac CC_STATUS_MDEP_INIT
A C expression to initialize the @code{mdep} field to ``empty''.
The default definition does nothing, since most machines don't use
the field anyway. If you want to use the field, you should probably
define this macro to initialize it.
This macro is not used on machines that do not use @code{cc0}.
+@end defmac
-@findex NOTICE_UPDATE_CC
-@item NOTICE_UPDATE_CC (@var{exp}, @var{insn})
+@defmac NOTICE_UPDATE_CC (@var{exp}, @var{insn})
A C compound statement to set the components of @code{cc_status}
appropriately for an insn @var{insn} whose body is @var{exp}. It is
this macro's responsibility to recognize insns that set the condition
that looks at an attribute (@pxref{Insn Attributes}) named, for example,
@samp{cc}. This avoids having detailed information about patterns in
two places, the @file{md} file and in @code{NOTICE_UPDATE_CC}.
+@end defmac
-@findex EXTRA_CC_MODES
-@item EXTRA_CC_MODES
-A list of additional modes for condition code values in registers
-(@pxref{Jump Patterns}). This macro should expand to a sequence of
-calls of the macro @code{CC} separated by white space. @code{CC} takes
-two arguments. The first is the enumeration name of the mode, which
-should begin with @samp{CC} and end with @samp{mode}. The second is a C
-string giving the printable name of the mode; it should be the same as
-the first argument, but with the trailing @samp{mode} removed.
-
-You should only define this macro if additional modes are required.
-
-A sample definition of @code{EXTRA_CC_MODES} is:
-@smallexample
-#define EXTRA_CC_MODES \
- CC(CC_NOOVmode, "CC_NOOV") \
- CC(CCFPmode, "CCFP") \
- CC(CCFPEmode, "CCFPE")
-@end smallexample
-
-@findex SELECT_CC_MODE
-@item SELECT_CC_MODE (@var{op}, @var{x}, @var{y})
+@defmac SELECT_CC_MODE (@var{op}, @var{x}, @var{y})
Returns a mode from class @code{MODE_CC} to be used when comparison
operation code @var{op} is applied to rtx @var{x} and @var{y}. For
-example, on the Sparc, @code{SELECT_CC_MODE} is defined as (see
+example, on the SPARC, @code{SELECT_CC_MODE} is defined as (see
@pxref{Jump Patterns} for a description of the reason for this
definition)
? CC_NOOVmode : CCmode))
@end smallexample
-You need not define this macro if @code{EXTRA_CC_MODES} is not defined.
+You should define this macro if and only if you define extra CC modes
+in @file{@var{machine}-modes.def}.
+@end defmac
-@findex CANONICALIZE_COMPARISON
-@item CANONICALIZE_COMPARISON (@var{code}, @var{op0}, @var{op1})
+@defmac CANONICALIZE_COMPARISON (@var{code}, @var{op0}, @var{op1})
On some machines not all possible comparisons are defined, but you can
convert an invalid comparison into a valid one. For example, the Alpha
does not have a @code{GT} comparison, but you can use an @code{LT}
You need not define this macro if it would never change the comparison
code or operands.
+@end defmac
-@findex REVERSIBLE_CC_MODE
-@item REVERSIBLE_CC_MODE (@var{mode})
+@defmac REVERSIBLE_CC_MODE (@var{mode})
A C expression whose value is one if it is always safe to reverse a
comparison whose mode is @var{mode}. If @code{SELECT_CC_MODE}
can ever return @var{mode} for a floating-point inequality comparison,
You need not define this macro if it would always returns zero or if the
floating-point format is anything other than @code{IEEE_FLOAT_FORMAT}.
-For example, here is the definition used on the Sparc, where floating-point
+For example, here is the definition used on the SPARC, where floating-point
inequality comparisons are always given @code{CCFPEmode}:
@smallexample
#define REVERSIBLE_CC_MODE(MODE) ((MODE) != CCFPEmode)
@end smallexample
+@end defmac
-@findex REVERSE_CONDITION (@var{code}, @var{mode})
+@defmac REVERSE_CONDITION (@var{code}, @var{mode})
A C expression whose value is reversed condition code of the @var{code} for
comparison done in CC_MODE @var{mode}. The macro is used only in case
@code{REVERSIBLE_CC_MODE (@var{mode})} is nonzero. Define this macro in case
((MODE) != CCFPmode ? reverse_condition (CODE) \
: reverse_condition_maybe_unordered (CODE))
@end smallexample
+@end defmac
-@findex REVERSE_CONDEXEC_PREDICATES_P
-@item REVERSE_CONDEXEC_PREDICATES_P (@var{code1}, @var{code2})
+@defmac REVERSE_CONDEXEC_PREDICATES_P (@var{op1}, @var{op2})
A C expression that returns true if the conditional execution predicate
-@var{code1} is the inverse of @var{code2} and vice versa. Define this to
-return 0 if the target has conditional execution predicates that cannot be
-reversed safely. If no expansion is specified, this macro is defined as
-follows:
+@var{op1}, a comparison operation, is the inverse of @var{op2} and vice
+versa. Define this to return 0 if the target has conditional execution
+predicates that cannot be reversed safely. There is no need to validate
+that the arguments of op1 and op2 are the same, this is done separately.
+If no expansion is specified, this macro is defined as follows:
@smallexample
#define REVERSE_CONDEXEC_PREDICATES_P (x, y) \
- ((x) == reverse_condition (y))
+ (GET_CODE ((x)) == reversed_comparison_code ((y), NULL))
@end smallexample
+@end defmac
+
+@deftypefn {Target Hook} bool TARGET_FIXED_CONDITION_CODE_REGS (unsigned int *, unsigned int *)
+On targets which do not use @code{(cc0)}, and which use a hard
+register rather than a pseudo-register to hold condition codes, the
+regular CSE passes are often not able to identify cases in which the
+hard register is set to a common value. Use this hook to enable a
+small pass which optimizes such cases. This hook should return true
+to enable this pass, and it should set the integers to which its
+arguments point to the hard register numbers used for condition codes.
+When there is only one such register, as is true on most systems, the
+integer pointed to by the second argument should be set to
+@code{INVALID_REGNUM}.
+
+The default version of this hook returns false.
+@end deftypefn
-@end table
+@deftypefn {Target Hook} enum machine_mode TARGET_CC_MODES_COMPATIBLE (enum machine_mode, enum machine_mode)
+On targets which use multiple condition code modes in class
+@code{MODE_CC}, it is sometimes the case that a comparison can be
+validly done in more than one mode. On such a system, define this
+target hook to take two mode arguments and to return a mode in which
+both comparisons may be validly done. If there is no such mode,
+return @code{VOIDmode}.
+
+The default version of this hook checks whether the modes are the
+same. If they are, it returns that mode. If they are different, it
+returns @code{VOIDmode}.
+@end deftypefn
@node Costs
@section Describing Relative Costs of Operations
These macros let you describe the relative speed of various operations
on the target machine.
-@table @code
-@findex CONST_COSTS
-@item CONST_COSTS (@var{x}, @var{code}, @var{outer_code})
-A part of a C @code{switch} statement that describes the relative costs
-of constant RTL expressions. It must contain @code{case} labels for
-expression codes @code{const_int}, @code{const}, @code{symbol_ref},
-@code{label_ref} and @code{const_double}. Each case must ultimately
-reach a @code{return} statement to return the relative cost of the use
-of that kind of constant value in an expression. The cost may depend on
-the precise value of the constant, which is available for examination in
-@var{x}, and the rtx code of the expression in which it is contained,
-found in @var{outer_code}.
-
-@var{code} is the expression code---redundant, since it can be
-obtained with @code{GET_CODE (@var{x})}.
-
-@findex RTX_COSTS
-@findex COSTS_N_INSNS
-@item RTX_COSTS (@var{x}, @var{code}, @var{outer_code})
-Like @code{CONST_COSTS} but applies to nonconstant RTL expressions.
-This can be used, for example, to indicate how costly a multiply
-instruction is. In writing this macro, you can use the construct
-@code{COSTS_N_INSNS (@var{n})} to specify a cost equal to @var{n} fast
-instructions. @var{outer_code} is the code of the expression in which
-@var{x} is contained.
-
-This macro is optional; do not define it if the default cost assumptions
-are adequate for the target machine.
-
-@findex DEFAULT_RTX_COSTS
-@item DEFAULT_RTX_COSTS (@var{x}, @var{code}, @var{outer_code})
-This macro, if defined, is called for any case not handled by the
-@code{RTX_COSTS} or @code{CONST_COSTS} macros. This eliminates the need
-to put case labels into the macro, but the code, or any functions it
-calls, must assume that the RTL in @var{x} could be of any type that has
-not already been handled. The arguments are the same as for
-@code{RTX_COSTS}, and the macro should execute a return statement giving
-the cost of any RTL expressions that it can handle. The default cost
-calculation is used for any RTL for which this macro does not return a
-value.
-
-This macro is optional; do not define it if the default cost assumptions
-are adequate for the target machine.
-
-@findex ADDRESS_COST
-@item ADDRESS_COST (@var{address})
-An expression giving the cost of an addressing mode that contains
-@var{address}. If not defined, the cost is computed from
-the @var{address} expression and the @code{CONST_COSTS} values.
-
-For most CISC machines, the default cost is a good approximation of the
-true cost of the addressing mode. However, on RISC machines, all
-instructions normally have the same length and execution time. Hence
-all addresses will have equal costs.
-
-In cases where more than one form of an address is known, the form with
-the lowest cost will be used. If multiple forms have the same, lowest,
-cost, the one that is the most complex will be used.
-
-For example, suppose an address that is equal to the sum of a register
-and a constant is used twice in the same basic block. When this macro
-is not defined, the address will be computed in a register and memory
-references will be indirect through that register. On machines where
-the cost of the addressing mode containing the sum is no higher than
-that of a simple indirect reference, this will produce an additional
-instruction and possibly require an additional register. Proper
-specification of this macro eliminates this overhead for such machines.
-
-Similar use of this macro is made in strength reduction of loops.
-
-@var{address} need not be valid as an address. In such a case, the cost
-is not relevant and can be any value; invalid addresses need not be
-assigned a different cost.
-
-On machines where an address involving more than one register is as
-cheap as an address computation involving only one register, defining
-@code{ADDRESS_COST} to reflect this can cause two registers to be live
-over a region of code where only one would have been if
-@code{ADDRESS_COST} were not defined in that manner. This effect should
-be considered in the definition of this macro. Equivalent costs should
-probably only be given to addresses with different numbers of registers
-on machines with lots of registers.
-
-This macro will normally either not be defined or be defined as a
-constant.
-
-@findex REGISTER_MOVE_COST
-@item REGISTER_MOVE_COST (@var{mode}, @var{from}, @var{to})
+@defmac REGISTER_MOVE_COST (@var{mode}, @var{from}, @var{to})
A C expression for the cost of moving data of mode @var{mode} from a
register in class @var{from} to one in class @var{to}. The classes are
expressed using the enumeration values such as @code{GENERAL_REGS}. A
constraints of the insn are met. Setting a cost of other than 2 will
allow reload to verify that the constraints are met. You should do this
if the @samp{mov@var{m}} pattern's constraints do not allow such copying.
+@end defmac
-@findex MEMORY_MOVE_COST
-@item MEMORY_MOVE_COST (@var{mode}, @var{class}, @var{in})
+@defmac MEMORY_MOVE_COST (@var{mode}, @var{class}, @var{in})
A C expression for the cost of moving data of mode @var{mode} between a
register of class @var{class} and memory; @var{in} is zero if the value
is to be written to memory, nonzero if it is to be read in. This cost
4 is not correct for your machine, define this macro to add some other
value to the result of that function. The arguments to that function
are the same as to this macro.
-
-@findex BRANCH_COST
-@item BRANCH_COST
-A C expression for the cost of a branch instruction. A value of 1 is
-the default; other values are interpreted relative to that.
-@end table
+@end defmac
+
+@defmac BRANCH_COST (@var{speed_p}, @var{predictable_p})
+A C expression for the cost of a branch instruction. A value of 1 is the
+default; other values are interpreted relative to that. Parameter @var{speed_p}
+is true when the branch in question should be optimized for speed. When
+it is false, @code{BRANCH_COST} should be returning value optimal for code size
+rather then performance considerations. @var{predictable_p} is true for well
+predictable branches. On many architectures the @code{BRANCH_COST} can be
+reduced then.
+@end defmac
Here are additional macros which do not specify precise relative costs,
but only that certain actions are more expensive than GCC would
ordinarily expect.
-@table @code
-@findex SLOW_BYTE_ACCESS
-@item SLOW_BYTE_ACCESS
+@defmac SLOW_BYTE_ACCESS
Define this macro as a C expression which is nonzero if accessing less
than a word of memory (i.e.@: a @code{char} or a @code{short}) is no
faster than accessing a word of memory, i.e., if such access
faster than word accesses, using word accesses is preferable since it
may eliminate subsequent memory access if subsequent accesses occur to
other fields in the same word of the structure, but to different bytes.
+@end defmac
-@findex SLOW_UNALIGNED_ACCESS
-@item SLOW_UNALIGNED_ACCESS (@var{mode}, @var{alignment})
+@defmac SLOW_UNALIGNED_ACCESS (@var{mode}, @var{alignment})
Define this macro to be the value 1 if memory accesses described by the
@var{mode} and @var{alignment} parameters have a cost many times greater
than aligned accesses, for example if they are emulated in a trap
If the value of this macro is always zero, it need not be defined. If
this macro is defined, it should produce a nonzero value when
@code{STRICT_ALIGNMENT} is nonzero.
+@end defmac
-@findex DONT_REDUCE_ADDR
-@item DONT_REDUCE_ADDR
-Define this macro to inhibit strength reduction of memory addresses.
-(On some machines, such strength reduction seems to do harm rather
-than good.)
-
-@findex MOVE_RATIO
-@item MOVE_RATIO
+@defmac MOVE_RATIO
The threshold of number of scalar memory-to-memory move insns, @emph{below}
which a sequence of insns should be generated instead of a
string move insn or a library call. Increasing the value will always
the number of such sequences.
If you don't define this, a reasonable default is used.
+@end defmac
-@findex MOVE_BY_PIECES_P
-@item MOVE_BY_PIECES_P (@var{size}, @var{alignment})
+@defmac MOVE_BY_PIECES_P (@var{size}, @var{alignment})
A C expression used to determine whether @code{move_by_pieces} will be used to
copy a chunk of memory, or whether some other block move mechanism
will be used. Defaults to 1 if @code{move_by_pieces_ninsns} returns less
than @code{MOVE_RATIO}.
+@end defmac
-@findex MOVE_MAX_PIECES
-@item MOVE_MAX_PIECES
+@defmac MOVE_MAX_PIECES
A C expression used by @code{move_by_pieces} to determine the largest unit
a load or store used to copy memory is. Defaults to @code{MOVE_MAX}.
+@end defmac
-@findex USE_LOAD_POST_INCREMENT
-@item USE_LOAD_POST_INCREMENT (@var{mode})
+@defmac CLEAR_RATIO
+The threshold of number of scalar move insns, @emph{below} which a sequence
+of insns should be generated to clear memory instead of a string clear insn
+or a library call. Increasing the value will always make code faster, but
+eventually incurs high cost in increased code size.
+
+If you don't define this, a reasonable default is used.
+@end defmac
+
+@defmac CLEAR_BY_PIECES_P (@var{size}, @var{alignment})
+A C expression used to determine whether @code{clear_by_pieces} will be used
+to clear a chunk of memory, or whether some other block clear mechanism
+will be used. Defaults to 1 if @code{move_by_pieces_ninsns} returns less
+than @code{CLEAR_RATIO}.
+@end defmac
+
+@defmac SET_RATIO
+The threshold of number of scalar move insns, @emph{below} which a sequence
+of insns should be generated to set memory to a constant value, instead of
+a block set insn or a library call.
+Increasing the value will always make code faster, but
+eventually incurs high cost in increased code size.
+
+If you don't define this, it defaults to the value of @code{MOVE_RATIO}.
+@end defmac
+
+@defmac SET_BY_PIECES_P (@var{size}, @var{alignment})
+A C expression used to determine whether @code{store_by_pieces} will be
+used to set a chunk of memory to a constant value, or whether some
+other mechanism will be used. Used by @code{__builtin_memset} when
+storing values other than constant zero.
+Defaults to 1 if @code{move_by_pieces_ninsns} returns less
+than @code{SET_RATIO}.
+@end defmac
+
+@defmac STORE_BY_PIECES_P (@var{size}, @var{alignment})
+A C expression used to determine whether @code{store_by_pieces} will be
+used to set a chunk of memory to a constant string value, or whether some
+other mechanism will be used. Used by @code{__builtin_strcpy} when
+called with a constant source string.
+Defaults to 1 if @code{move_by_pieces_ninsns} returns less
+than @code{MOVE_RATIO}.
+@end defmac
+
+@defmac USE_LOAD_POST_INCREMENT (@var{mode})
A C expression used to determine whether a load postincrement is a good
thing to use for a given mode. Defaults to the value of
@code{HAVE_POST_INCREMENT}.
+@end defmac
-@findex USE_LOAD_POST_DECREMENT
-@item USE_LOAD_POST_DECREMENT (@var{mode})
+@defmac USE_LOAD_POST_DECREMENT (@var{mode})
A C expression used to determine whether a load postdecrement is a good
thing to use for a given mode. Defaults to the value of
@code{HAVE_POST_DECREMENT}.
+@end defmac
-@findex USE_LOAD_PRE_INCREMENT
-@item USE_LOAD_PRE_INCREMENT (@var{mode})
+@defmac USE_LOAD_PRE_INCREMENT (@var{mode})
A C expression used to determine whether a load preincrement is a good
thing to use for a given mode. Defaults to the value of
@code{HAVE_PRE_INCREMENT}.
+@end defmac
-@findex USE_LOAD_PRE_DECREMENT
-@item USE_LOAD_PRE_DECREMENT (@var{mode})
+@defmac USE_LOAD_PRE_DECREMENT (@var{mode})
A C expression used to determine whether a load predecrement is a good
thing to use for a given mode. Defaults to the value of
@code{HAVE_PRE_DECREMENT}.
+@end defmac
-@findex USE_STORE_POST_INCREMENT
-@item USE_STORE_POST_INCREMENT (@var{mode})
+@defmac USE_STORE_POST_INCREMENT (@var{mode})
A C expression used to determine whether a store postincrement is a good
thing to use for a given mode. Defaults to the value of
@code{HAVE_POST_INCREMENT}.
+@end defmac
-@findex USE_STORE_POST_DECREMENT
-@item USE_STORE_POST_DECREMENT (@var{mode})
+@defmac USE_STORE_POST_DECREMENT (@var{mode})
A C expression used to determine whether a store postdecrement is a good
thing to use for a given mode. Defaults to the value of
@code{HAVE_POST_DECREMENT}.
+@end defmac
-@findex USE_STORE_PRE_INCREMENT
-@item USE_STORE_PRE_INCREMENT (@var{mode})
+@defmac USE_STORE_PRE_INCREMENT (@var{mode})
This macro is used to determine whether a store preincrement is a good
thing to use for a given mode. Defaults to the value of
@code{HAVE_PRE_INCREMENT}.
+@end defmac
-@findex USE_STORE_PRE_DECREMENT
-@item USE_STORE_PRE_DECREMENT (@var{mode})
+@defmac USE_STORE_PRE_DECREMENT (@var{mode})
This macro is used to determine whether a store predecrement is a good
thing to use for a given mode. Defaults to the value of
@code{HAVE_PRE_DECREMENT}.
+@end defmac
-@findex NO_FUNCTION_CSE
-@item NO_FUNCTION_CSE
+@defmac NO_FUNCTION_CSE
Define this macro if it is as good or better to call a constant
function address than to call an address kept in a register.
+@end defmac
-@findex NO_RECURSIVE_FUNCTION_CSE
-@item NO_RECURSIVE_FUNCTION_CSE
-Define this macro if it is as good or better for a function to call
-itself with an explicit address than to call an address kept in a
-register.
-@end table
+@defmac RANGE_TEST_NON_SHORT_CIRCUIT
+Define this macro if a non-short-circuit operation produced by
+@samp{fold_range_test ()} is optimal. This macro defaults to true if
+@code{BRANCH_COST} is greater than or equal to the value 2.
+@end defmac
+
+@deftypefn {Target Hook} bool TARGET_RTX_COSTS (rtx @var{x}, int @var{code}, int @var{outer_code}, int *@var{total})
+This target hook describes the relative costs of RTL expressions.
+
+The cost may depend on the precise form of the expression, which is
+available for examination in @var{x}, and the rtx code of the expression
+in which it is contained, found in @var{outer_code}. @var{code} is the
+expression code---redundant, since it can be obtained with
+@code{GET_CODE (@var{x})}.
+
+In implementing this hook, you can use the construct
+@code{COSTS_N_INSNS (@var{n})} to specify a cost equal to @var{n} fast
+instructions.
+
+On entry to the hook, @code{*@var{total}} contains a default estimate
+for the cost of the expression. The hook should modify this value as
+necessary. Traditionally, the default costs are @code{COSTS_N_INSNS (5)}
+for multiplications, @code{COSTS_N_INSNS (7)} for division and modulus
+operations, and @code{COSTS_N_INSNS (1)} for all other operations.
+
+When optimizing for code size, i.e.@: when @code{optimize_size} is
+nonzero, this target hook should be used to estimate the relative
+size cost of an expression, again relative to @code{COSTS_N_INSNS}.
+
+The hook returns true when all subexpressions of @var{x} have been
+processed, and false when @code{rtx_cost} should recurse.
+@end deftypefn
+
+@deftypefn {Target Hook} int TARGET_ADDRESS_COST (rtx @var{address})
+This hook computes the cost of an addressing mode that contains
+@var{address}. If not defined, the cost is computed from
+the @var{address} expression and the @code{TARGET_RTX_COST} hook.
+
+For most CISC machines, the default cost is a good approximation of the
+true cost of the addressing mode. However, on RISC machines, all
+instructions normally have the same length and execution time. Hence
+all addresses will have equal costs.
+
+In cases where more than one form of an address is known, the form with
+the lowest cost will be used. If multiple forms have the same, lowest,
+cost, the one that is the most complex will be used.
+
+For example, suppose an address that is equal to the sum of a register
+and a constant is used twice in the same basic block. When this macro
+is not defined, the address will be computed in a register and memory
+references will be indirect through that register. On machines where
+the cost of the addressing mode containing the sum is no higher than
+that of a simple indirect reference, this will produce an additional
+instruction and possibly require an additional register. Proper
+specification of this macro eliminates this overhead for such machines.
+
+This hook is never called with an invalid address.
+
+On machines where an address involving more than one register is as
+cheap as an address computation involving only one register, defining
+@code{TARGET_ADDRESS_COST} to reflect this can cause two registers to
+be live over a region of code where only one would have been if
+@code{TARGET_ADDRESS_COST} were not defined in that manner. This effect
+should be considered in the definition of this macro. Equivalent costs
+should probably only be given to addresses with different numbers of
+registers on machines with lots of registers.
+@end deftypefn
@node Scheduling
@section Adjusting the Instruction Scheduler
them: try the first ones in this list first.
@deftypefn {Target Hook} int TARGET_SCHED_ISSUE_RATE (void)
-This hook returns the maximum number of instructions that can ever issue
-at the same time on the target machine. The default is one. This value
-must be constant over the entire compilation. If you need it to vary
-depending on what the instructions are, you must use
+This hook returns the maximum number of instructions that can ever
+issue at the same time on the target machine. The default is one.
+Although the insn scheduler can define itself the possibility of issue
+an insn on the same cycle, the value can serve as an additional
+constraint to issue insns on the same simulated processor cycle (see
+hooks @samp{TARGET_SCHED_REORDER} and @samp{TARGET_SCHED_REORDER2}).
+This value must be constant over the entire compilation. If you need
+it to vary depending on what the instructions are, you must use
@samp{TARGET_SCHED_VARIABLE_ISSUE}.
@end deftypefn
@deftypefn {Target Hook} int TARGET_SCHED_VARIABLE_ISSUE (FILE *@var{file}, int @var{verbose}, rtx @var{insn}, int @var{more})
This hook is executed by the scheduler after it has scheduled an insn
from the ready list. It should return the number of insns which can
-still be issued in the current cycle. Normally this is
-@samp{@w{@var{more} - 1}}. You should define this hook if some insns
-take more machine resources than others, so that fewer insns can follow
-them in the same cycle. @var{file} is either a null pointer, or a stdio
-stream to write any debug output to. @var{verbose} is the verbose level
-provided by @option{-fsched-verbose-@var{n}}. @var{insn} is the
-instruction that was scheduled.
+still be issued in the current cycle. The default is
+@samp{@w{@var{more} - 1}} for insns other than @code{CLOBBER} and
+@code{USE}, which normally are not counted against the issue rate.
+You should define this hook if some insns take more machine resources
+than others, so that fewer insns can follow them in the same cycle.
+@var{file} is either a null pointer, or a stdio stream to write any
+debug output to. @var{verbose} is the verbose level provided by
+@option{-fsched-verbose-@var{n}}. @var{insn} is the instruction that
+was scheduled.
@end deftypefn
@deftypefn {Target Hook} int TARGET_SCHED_ADJUST_COST (rtx @var{insn}, rtx @var{link}, rtx @var{dep_insn}, int @var{cost})
-This function corrects the value of @var{cost} based on the relationship
-between @var{insn} and @var{dep_insn} through the dependence @var{link}.
-It should return the new value. The default is to make no adjustment to
-@var{cost}. This can be used for example to specify to the scheduler
+This function corrects the value of @var{cost} based on the
+relationship between @var{insn} and @var{dep_insn} through the
+dependence @var{link}. It should return the new value. The default
+is to make no adjustment to @var{cost}. This can be used for example
+to specify to the scheduler using the traditional pipeline description
that an output- or anti-dependence does not incur the same cost as a
-data-dependence.
+data-dependence. If the scheduler using the automaton based pipeline
+description, the cost of anti-dependence is zero and the cost of
+output-dependence is maximum of one and the difference of latency
+times of the first and the second insns. If these values are not
+acceptable, you could use the hook to modify them too. See also
+@pxref{Processor pipeline description}.
@end deftypefn
@deftypefn {Target Hook} int TARGET_SCHED_ADJUST_PRIORITY (rtx @var{insn}, int @var{priority})
This hook adjusts the integer scheduling priority @var{priority} of
-@var{insn}. It should return the new priority. Reduce the priority to
-execute @var{insn} earlier, increase the priority to execute @var{insn}
+@var{insn}. It should return the new priority. Increase the priority to
+execute @var{insn} earlier, reduce the priority to execute @var{insn}
later. Do not define this hook if you do not need to adjust the
scheduling priorities of insns.
@end deftypefn
cycle. These other insns can then be taken into account properly.
@end deftypefn
+@deftypefn {Target Hook} void TARGET_SCHED_DEPENDENCIES_EVALUATION_HOOK (rtx @var{head}, rtx @var{tail})
+This hook is called after evaluation forward dependencies of insns in
+chain given by two parameter values (@var{head} and @var{tail}
+correspondingly) but before insns scheduling of the insn chain. For
+example, it can be used for better insn classification if it requires
+analysis of dependencies. This hook can use backward and forward
+dependencies of the insn scheduler because they are already
+calculated.
+@end deftypefn
+
@deftypefn {Target Hook} void TARGET_SCHED_INIT (FILE *@var{file}, int @var{verbose}, int @var{max_ready})
This hook is executed by the scheduler at the beginning of each block of
instructions that are to be scheduled. @var{file} is either a null
is the verbose level provided by @option{-fsched-verbose-@var{n}}.
@var{max_ready} is the maximum number of insns in the current scheduling
region that can be live at the same time. This can be used to allocate
-scratch space if it is needed, e.g. by @samp{TARGET_SCHED_REORDER}.
+scratch space if it is needed, e.g.@: by @samp{TARGET_SCHED_REORDER}.
@end deftypefn
@deftypefn {Target Hook} void TARGET_SCHED_FINISH (FILE *@var{file}, int @var{verbose})
@option{-fsched-verbose-@var{n}}.
@end deftypefn
-@deftypefn {Target Hook} rtx TARGET_SCHED_CYCLE_DISPLAY (int @var{clock}, rtx @var{last})
-This hook is called in verbose mode only, at the beginning of each pass
-over a basic block. It should insert an insn into the chain after
-@var{last}, which has no effect, but records the value @var{clock} in
-RTL dumps and assembly output. Define this hook only if you need this
-level of detail about what the scheduler is doing.
+@deftypefn {Target Hook} void TARGET_SCHED_INIT_GLOBAL (FILE *@var{file}, int @var{verbose}, int @var{old_max_uid})
+This hook is executed by the scheduler after function level initializations.
+@var{file} is either a null pointer, or a stdio stream to write any debug output to.
+@var{verbose} is the verbose level provided by @option{-fsched-verbose-@var{n}}.
+@var{old_max_uid} is the maximum insn uid when scheduling begins.
@end deftypefn
-@node Sections
-@section Dividing the Output into Sections (Texts, Data, @dots{})
-@c the above section title is WAY too long. maybe cut the part between
-@c the (...)? --mew 10feb93
+@deftypefn {Target Hook} void TARGET_SCHED_FINISH_GLOBAL (FILE *@var{file}, int @var{verbose})
+This is the cleanup hook corresponding to @code{TARGET_SCHED_INIT_GLOBAL}.
+@var{file} is either a null pointer, or a stdio stream to write any debug output to.
+@var{verbose} is the verbose level provided by @option{-fsched-verbose-@var{n}}.
+@end deftypefn
-An object file is divided into sections containing different types of
-data. In the most common case, there are three sections: the @dfn{text
-section}, which holds instructions and read-only data; the @dfn{data
-section}, which holds initialized writable data; and the @dfn{bss
-section}, which holds uninitialized data. Some systems have other kinds
-of sections.
+@deftypefn {Target Hook} int TARGET_SCHED_DFA_PRE_CYCLE_INSN (void)
+The hook returns an RTL insn. The automaton state used in the
+pipeline hazard recognizer is changed as if the insn were scheduled
+when the new simulated processor cycle starts. Usage of the hook may
+simplify the automaton pipeline description for some @acronym{VLIW}
+processors. If the hook is defined, it is used only for the automaton
+based pipeline description. The default is not to change the state
+when the new simulated processor cycle starts.
+@end deftypefn
-The compiler must tell the assembler when to switch sections. These
-macros control what commands to output to tell the assembler this. You
-can also define additional sections.
+@deftypefn {Target Hook} void TARGET_SCHED_INIT_DFA_PRE_CYCLE_INSN (void)
+The hook can be used to initialize data used by the previous hook.
+@end deftypefn
-@table @code
-@findex TEXT_SECTION_ASM_OP
-@item TEXT_SECTION_ASM_OP
-A C expression whose value is a string, including spacing, containing the
-assembler operation that should precede instructions and read-only data.
-Normally @code{"\t.text"} is right.
+@deftypefn {Target Hook} int TARGET_SCHED_DFA_POST_CYCLE_INSN (void)
+The hook is analogous to @samp{TARGET_SCHED_DFA_PRE_CYCLE_INSN} but used
+to changed the state as if the insn were scheduled when the new
+simulated processor cycle finishes.
+@end deftypefn
-@findex TEXT_SECTION
-@item TEXT_SECTION
-A C statement that switches to the default section containing instructions.
-Normally this is not needed, as simply defining @code{TEXT_SECTION_ASM_OP}
-is enough. The MIPS port uses this to sort all functions after all data
-declarations.
+@deftypefn {Target Hook} void TARGET_SCHED_INIT_DFA_POST_CYCLE_INSN (void)
+The hook is analogous to @samp{TARGET_SCHED_INIT_DFA_PRE_CYCLE_INSN} but
+used to initialize data used by the previous hook.
+@end deftypefn
-@findex DATA_SECTION_ASM_OP
-@item DATA_SECTION_ASM_OP
+@deftypefn {Target Hook} void TARGET_SCHED_DFA_PRE_CYCLE_ADVANCE (void)
+The hook to notify target that the current simulated cycle is about to finish.
+The hook is analogous to @samp{TARGET_SCHED_DFA_PRE_CYCLE_INSN} but used
+to change the state in more complicated situations - e.g., when advancing
+state on a single insn is not enough.
+@end deftypefn
+
+@deftypefn {Target Hook} void TARGET_SCHED_DFA_POST_CYCLE_ADVANCE (void)
+The hook to notify target that new simulated cycle has just started.
+The hook is analogous to @samp{TARGET_SCHED_DFA_POST_CYCLE_INSN} but used
+to change the state in more complicated situations - e.g., when advancing
+state on a single insn is not enough.
+@end deftypefn
+
+@deftypefn {Target Hook} int TARGET_SCHED_FIRST_CYCLE_MULTIPASS_DFA_LOOKAHEAD (void)
+This hook controls better choosing an insn from the ready insn queue
+for the @acronym{DFA}-based insn scheduler. Usually the scheduler
+chooses the first insn from the queue. If the hook returns a positive
+value, an additional scheduler code tries all permutations of
+@samp{TARGET_SCHED_FIRST_CYCLE_MULTIPASS_DFA_LOOKAHEAD ()}
+subsequent ready insns to choose an insn whose issue will result in
+maximal number of issued insns on the same cycle. For the
+@acronym{VLIW} processor, the code could actually solve the problem of
+packing simple insns into the @acronym{VLIW} insn. Of course, if the
+rules of @acronym{VLIW} packing are described in the automaton.
+
+This code also could be used for superscalar @acronym{RISC}
+processors. Let us consider a superscalar @acronym{RISC} processor
+with 3 pipelines. Some insns can be executed in pipelines @var{A} or
+@var{B}, some insns can be executed only in pipelines @var{B} or
+@var{C}, and one insn can be executed in pipeline @var{B}. The
+processor may issue the 1st insn into @var{A} and the 2nd one into
+@var{B}. In this case, the 3rd insn will wait for freeing @var{B}
+until the next cycle. If the scheduler issues the 3rd insn the first,
+the processor could issue all 3 insns per cycle.
+
+Actually this code demonstrates advantages of the automaton based
+pipeline hazard recognizer. We try quickly and easy many insn
+schedules to choose the best one.
+
+The default is no multipass scheduling.
+@end deftypefn
+
+@deftypefn {Target Hook} int TARGET_SCHED_FIRST_CYCLE_MULTIPASS_DFA_LOOKAHEAD_GUARD (rtx)
+
+This hook controls what insns from the ready insn queue will be
+considered for the multipass insn scheduling. If the hook returns
+zero for insn passed as the parameter, the insn will be not chosen to
+be issued.
+
+The default is that any ready insns can be chosen to be issued.
+@end deftypefn
+
+@deftypefn {Target Hook} int TARGET_SCHED_DFA_NEW_CYCLE (FILE *, int, rtx, int, int, int *)
+
+This hook is called by the insn scheduler before issuing insn passed
+as the third parameter on given cycle. If the hook returns nonzero,
+the insn is not issued on given processors cycle. Instead of that,
+the processor cycle is advanced. If the value passed through the last
+parameter is zero, the insn ready queue is not sorted on the new cycle
+start as usually. The first parameter passes file for debugging
+output. The second one passes the scheduler verbose level of the
+debugging output. The forth and the fifth parameter values are
+correspondingly processor cycle on which the previous insn has been
+issued and the current processor cycle.
+@end deftypefn
+
+@deftypefn {Target Hook} bool TARGET_SCHED_IS_COSTLY_DEPENDENCE (struct dep_def *@var{_dep}, int @var{cost}, int @var{distance})
+This hook is used to define which dependences are considered costly by
+the target, so costly that it is not advisable to schedule the insns that
+are involved in the dependence too close to one another. The parameters
+to this hook are as follows: The first parameter @var{_dep} is the dependence
+being evaluated. The second parameter @var{cost} is the cost of the
+dependence, and the third
+parameter @var{distance} is the distance in cycles between the two insns.
+The hook returns @code{true} if considering the distance between the two
+insns the dependence between them is considered costly by the target,
+and @code{false} otherwise.
+
+Defining this hook can be useful in multiple-issue out-of-order machines,
+where (a) it's practically hopeless to predict the actual data/resource
+delays, however: (b) there's a better chance to predict the actual grouping
+that will be formed, and (c) correctly emulating the grouping can be very
+important. In such targets one may want to allow issuing dependent insns
+closer to one another---i.e., closer than the dependence distance; however,
+not in cases of "costly dependences", which this hooks allows to define.
+@end deftypefn
+
+@deftypefn {Target Hook} void TARGET_SCHED_H_I_D_EXTENDED (void)
+This hook is called by the insn scheduler after emitting a new instruction to
+the instruction stream. The hook notifies a target backend to extend its
+per instruction data structures.
+@end deftypefn
+
+@deftypefn {Target Hook} void * TARGET_SCHED_ALLOC_SCHED_CONTEXT (void)
+Return a pointer to a store large enough to hold target scheduling context.
+@end deftypefn
+
+@deftypefn {Target Hook} void TARGET_SCHED_INIT_SCHED_CONTEXT (void *@var{tc}, bool @var{clean_p})
+Initialize store pointed to by @var{tc} to hold target scheduling context.
+It @var{clean_p} is true then initialize @var{tc} as if scheduler is at the
+beginning of the block. Otherwise, make a copy of the current context in
+@var{tc}.
+@end deftypefn
+
+@deftypefn {Target Hook} void TARGET_SCHED_SET_SCHED_CONTEXT (void *@var{tc})
+Copy target scheduling context pointer to by @var{tc} to the current context.
+@end deftypefn
+
+@deftypefn {Target Hook} void TARGET_SCHED_CLEAR_SCHED_CONTEXT (void *@var{tc})
+Deallocate internal data in target scheduling context pointed to by @var{tc}.
+@end deftypefn
+
+@deftypefn {Target Hook} void TARGET_SCHED_FREE_SCHED_CONTEXT (void *@var{tc})
+Deallocate a store for target scheduling context pointed to by @var{tc}.
+@end deftypefn
+
+@deftypefn {Target Hook} void * TARGET_SCHED_ALLOC_SCHED_CONTEXT (void)
+Return a pointer to a store large enough to hold target scheduling context.
+@end deftypefn
+
+@deftypefn {Target Hook} void TARGET_SCHED_INIT_SCHED_CONTEXT (void *@var{tc}, bool @var{clean_p})
+Initialize store pointed to by @var{tc} to hold target scheduling context.
+It @var{clean_p} is true then initialize @var{tc} as if scheduler is at the
+beginning of the block. Otherwise, make a copy of the current context in
+@var{tc}.
+@end deftypefn
+
+@deftypefn {Target Hook} void TARGET_SCHED_SET_SCHED_CONTEXT (void *@var{tc})
+Copy target scheduling context pointer to by @var{tc} to the current context.
+@end deftypefn
+
+@deftypefn {Target Hook} void TARGET_SCHED_CLEAR_SCHED_CONTEXT (void *@var{tc})
+Deallocate internal data in target scheduling context pointed to by @var{tc}.
+@end deftypefn
+
+@deftypefn {Target Hook} void TARGET_SCHED_FREE_SCHED_CONTEXT (void *@var{tc})
+Deallocate a store for target scheduling context pointed to by @var{tc}.
+@end deftypefn
+
+@deftypefn {Target Hook} int TARGET_SCHED_SPECULATE_INSN (rtx @var{insn}, int @var{request}, rtx *@var{new_pat})
+This hook is called by the insn scheduler when @var{insn} has only
+speculative dependencies and therefore can be scheduled speculatively.
+The hook is used to check if the pattern of @var{insn} has a speculative
+version and, in case of successful check, to generate that speculative
+pattern. The hook should return 1, if the instruction has a speculative form,
+or -1, if it doesn't. @var{request} describes the type of requested
+speculation. If the return value equals 1 then @var{new_pat} is assigned
+the generated speculative pattern.
+@end deftypefn
+
+@deftypefn {Target Hook} int TARGET_SCHED_NEEDS_BLOCK_P (rtx @var{insn})
+This hook is called by the insn scheduler during generation of recovery code
+for @var{insn}. It should return nonzero, if the corresponding check
+instruction should branch to recovery code, or zero otherwise.
+@end deftypefn
+
+@deftypefn {Target Hook} rtx TARGET_SCHED_GEN_CHECK (rtx @var{insn}, rtx @var{label}, int @var{mutate_p})
+This hook is called by the insn scheduler to generate a pattern for recovery
+check instruction. If @var{mutate_p} is zero, then @var{insn} is a
+speculative instruction for which the check should be generated.
+@var{label} is either a label of a basic block, where recovery code should
+be emitted, or a null pointer, when requested check doesn't branch to
+recovery code (a simple check). If @var{mutate_p} is nonzero, then
+a pattern for a branchy check corresponding to a simple check denoted by
+@var{insn} should be generated. In this case @var{label} can't be null.
+@end deftypefn
+
+@deftypefn {Target Hook} int TARGET_SCHED_FIRST_CYCLE_MULTIPASS_DFA_LOOKAHEAD_GUARD_SPEC (rtx @var{insn})
+This hook is used as a workaround for
+@samp{TARGET_SCHED_FIRST_CYCLE_MULTIPASS_DFA_LOOKAHEAD_GUARD} not being
+called on the first instruction of the ready list. The hook is used to
+discard speculative instruction that stand first in the ready list from
+being scheduled on the current cycle. For non-speculative instructions,
+the hook should always return nonzero. For example, in the ia64 backend
+the hook is used to cancel data speculative insns when the ALAT table
+is nearly full.
+@end deftypefn
+
+@deftypefn {Target Hook} void TARGET_SCHED_SET_SCHED_FLAGS (unsigned int *@var{flags}, spec_info_t @var{spec_info})
+This hook is used by the insn scheduler to find out what features should be
+enabled/used. @var{flags} initially may have either the SCHED_RGN or SCHED_EBB
+bit set. This denotes the scheduler pass for which the data should be
+provided. The target backend should modify @var{flags} by modifying
+the bits corresponding to the following features: USE_DEPS_LIST, USE_GLAT,
+DETACH_LIFE_INFO, and DO_SPECULATION@. For the DO_SPECULATION feature
+an additional structure @var{spec_info} should be filled by the target.
+The structure describes speculation types that can be used in the scheduler.
+@end deftypefn
+
+@deftypefn {Target Hook} int TARGET_SCHED_SMS_RES_MII (struct ddg *@var{g})
+This hook is called by the swing modulo scheduler to calculate a
+resource-based lower bound which is based on the resources available in
+the machine and the resources required by each instruction. The target
+backend can use @var{g} to calculate such bound. A very simple lower
+bound will be used in case this hook is not implemented: the total number
+of instructions divided by the issue rate.
+@end deftypefn
+
+@node Sections
+@section Dividing the Output into Sections (Texts, Data, @dots{})
+@c the above section title is WAY too long. maybe cut the part between
+@c the (...)? --mew 10feb93
+
+An object file is divided into sections containing different types of
+data. In the most common case, there are three sections: the @dfn{text
+section}, which holds instructions and read-only data; the @dfn{data
+section}, which holds initialized writable data; and the @dfn{bss
+section}, which holds uninitialized data. Some systems have other kinds
+of sections.
+
+@file{varasm.c} provides several well-known sections, such as
+@code{text_section}, @code{data_section} and @code{bss_section}.
+The normal way of controlling a @code{@var{foo}_section} variable
+is to define the associated @code{@var{FOO}_SECTION_ASM_OP} macro,
+as described below. The macros are only read once, when @file{varasm.c}
+initializes itself, so their values must be run-time constants.
+They may however depend on command-line flags.
+
+@emph{Note:} Some run-time files, such @file{crtstuff.c}, also make
+use of the @code{@var{FOO}_SECTION_ASM_OP} macros, and expect them
+to be string literals.
+
+Some assemblers require a different string to be written every time a
+section is selected. If your assembler falls into this category, you
+should define the @code{TARGET_ASM_INIT_SECTIONS} hook and use
+@code{get_unnamed_section} to set up the sections.
+
+You must always create a @code{text_section}, either by defining
+@code{TEXT_SECTION_ASM_OP} or by initializing @code{text_section}
+in @code{TARGET_ASM_INIT_SECTIONS}. The same is true of
+@code{data_section} and @code{DATA_SECTION_ASM_OP}. If you do not
+create a distinct @code{readonly_data_section}, the default is to
+reuse @code{text_section}.
+
+All the other @file{varasm.c} sections are optional, and are null
+if the target does not provide them.
+
+@defmac TEXT_SECTION_ASM_OP
+A C expression whose value is a string, including spacing, containing the
+assembler operation that should precede instructions and read-only data.
+Normally @code{"\t.text"} is right.
+@end defmac
+
+@defmac HOT_TEXT_SECTION_NAME
+If defined, a C string constant for the name of the section containing most
+frequently executed functions of the program. If not defined, GCC will provide
+a default definition if the target supports named sections.
+@end defmac
+
+@defmac UNLIKELY_EXECUTED_TEXT_SECTION_NAME
+If defined, a C string constant for the name of the section containing unlikely
+executed functions in the program.
+@end defmac
+
+@defmac DATA_SECTION_ASM_OP
A C expression whose value is a string, including spacing, containing the
assembler operation to identify the following data as writable initialized
data. Normally @code{"\t.data"} is right.
+@end defmac
-@findex SHARED_SECTION_ASM_OP
-@item SHARED_SECTION_ASM_OP
+@defmac SDATA_SECTION_ASM_OP
If defined, a C expression whose value is a string, including spacing,
containing the assembler operation to identify the following data as
-shared data. If not defined, @code{DATA_SECTION_ASM_OP} will be used.
+initialized, writable small data.
+@end defmac
-@findex BSS_SECTION_ASM_OP
-@item BSS_SECTION_ASM_OP
+@defmac READONLY_DATA_SECTION_ASM_OP
+A C expression whose value is a string, including spacing, containing the
+assembler operation to identify the following data as read-only initialized
+data.
+@end defmac
+
+@defmac BSS_SECTION_ASM_OP
If defined, a C expression whose value is a string, including spacing,
containing the assembler operation to identify the following data as
uninitialized global data. If not defined, and neither
uninitialized global data will be output in the data section if
@option{-fno-common} is passed, otherwise @code{ASM_OUTPUT_COMMON} will be
used.
+@end defmac
-@findex SHARED_BSS_SECTION_ASM_OP
-@item SHARED_BSS_SECTION_ASM_OP
+@defmac SBSS_SECTION_ASM_OP
If defined, a C expression whose value is a string, including spacing,
containing the assembler operation to identify the following data as
-uninitialized global shared data. If not defined, and
-@code{BSS_SECTION_ASM_OP} is, the latter will be used.
+uninitialized, writable small data.
+@end defmac
-@findex INIT_SECTION_ASM_OP
-@item INIT_SECTION_ASM_OP
+@defmac INIT_SECTION_ASM_OP
If defined, a C expression whose value is a string, including spacing,
containing the assembler operation to identify the following data as
initialization code. If not defined, GCC will assume such a section does
-not exist.
+not exist. This section has no corresponding @code{init_section}
+variable; it is used entirely in runtime code.
+@end defmac
-@findex FINI_SECTION_ASM_OP
-@item FINI_SECTION_ASM_OP
+@defmac FINI_SECTION_ASM_OP
If defined, a C expression whose value is a string, including spacing,
containing the assembler operation to identify the following data as
finalization code. If not defined, GCC will assume such a section does
-not exist.
+not exist. This section has no corresponding @code{fini_section}
+variable; it is used entirely in runtime code.
+@end defmac
-@findex CRT_CALL_STATIC_FUNCTION
-@item CRT_CALL_STATIC_FUNCTION (@var{section_op}, @var{function})
+@defmac INIT_ARRAY_SECTION_ASM_OP
+If defined, a C expression whose value is a string, including spacing,
+containing the assembler operation to identify the following data as
+part of the @code{.init_array} (or equivalent) section. If not
+defined, GCC will assume such a section does not exist. Do not define
+both this macro and @code{INIT_SECTION_ASM_OP}.
+@end defmac
+
+@defmac FINI_ARRAY_SECTION_ASM_OP
+If defined, a C expression whose value is a string, including spacing,
+containing the assembler operation to identify the following data as
+part of the @code{.fini_array} (or equivalent) section. If not
+defined, GCC will assume such a section does not exist. Do not define
+both this macro and @code{FINI_SECTION_ASM_OP}.
+@end defmac
+
+@defmac CRT_CALL_STATIC_FUNCTION (@var{section_op}, @var{function})
If defined, an ASM statement that switches to a different section
via @var{section_op}, calls @var{function}, and switches back to
the text section. This is used in @file{crtstuff.c} if
ports need hand-crafted assembly code to avoid dependencies on
registers initialized in the function prologue or to ensure that
constant pools don't end up too far way in the text section.
-
-@findex FORCE_CODE_SECTION_ALIGN
-@item FORCE_CODE_SECTION_ALIGN
+@end defmac
+
+@defmac TARGET_LIBGCC_SDATA_SECTION
+If defined, a string which names the section into which small
+variables defined in crtstuff and libgcc should go. This is useful
+when the target has options for optimizing access to small data, and
+you want the crtstuff and libgcc routines to be conservative in what
+they expect of your application yet liberal in what your application
+expects. For example, for targets with a @code{.sdata} section (like
+MIPS), you could compile crtstuff with @code{-G 0} so that it doesn't
+require small data support from your application, but use this macro
+to put small data into @code{.sdata} so that your application can
+access these variables whether it uses small data or not.
+@end defmac
+
+@defmac FORCE_CODE_SECTION_ALIGN
If defined, an ASM statement that aligns a code section to some
arbitrary boundary. This is used to force all fragments of the
@code{.init} and @code{.fini} sections to have to same alignment
and thus prevent the linker from having to add any padding.
+@end defmac
-@findex EXTRA_SECTIONS
-@findex in_text
-@findex in_data
-@item EXTRA_SECTIONS
-A list of names for sections other than the standard two, which are
-@code{in_text} and @code{in_data}. You need not define this macro
-on a system with no other sections (that GCC needs to use).
-
-@findex EXTRA_SECTION_FUNCTIONS
-@findex text_section
-@findex data_section
-@item EXTRA_SECTION_FUNCTIONS
-One or more functions to be defined in @file{varasm.c}. These
-functions should do jobs analogous to those of @code{text_section} and
-@code{data_section}, for your additional sections. Do not define this
-macro if you do not define @code{EXTRA_SECTIONS}.
-
-@findex READONLY_DATA_SECTION
-@item READONLY_DATA_SECTION
-On most machines, read-only variables, constants, and jump tables are
-placed in the text section. If this is not the case on your machine,
-this macro should be defined to be the name of a function (either
-@code{data_section} or a function defined in @code{EXTRA_SECTIONS}) that
-switches to the section to be used for read-only items.
-
-If these items should be placed in the text section, this macro should
-not be defined.
-
-@findex SELECT_SECTION
-@item SELECT_SECTION (@var{exp}, @var{reloc}, @var{align})
-A C statement or statements to switch to the appropriate section for
-output of @var{exp}. You can assume that @var{exp} is either a
-@code{VAR_DECL} node or a constant of some sort. @var{reloc}
-indicates whether the initial value of @var{exp} requires link-time
-relocations. Bit 1 is set when variable contains local relocations
-only, while bit 2 is set for global relocations.
-Select the section by calling @code{text_section} or one
-of the alternatives for other sections. @var{align} is the constant
-alignment in bits.
-
-Do not define this macro if you put all read-only variables and
-constants in the read-only data section (usually the text section).
-
-@findex SELECT_RTX_SECTION
-@item SELECT_RTX_SECTION (@var{mode}, @var{rtx}, @var{align})
-A C statement or statements to switch to the appropriate section for
-output of @var{rtx} in mode @var{mode}. You can assume that @var{rtx}
-is some kind of constant in RTL@. The argument @var{mode} is redundant
-except in the case of a @code{const_int} rtx. Select the section by
-calling @code{text_section} or one of the alternatives for other
-sections. @var{align} is the constant alignment in bits.
-
-Do not define this macro if you put all constants in the read-only
-data section.
-
-@findex JUMP_TABLES_IN_TEXT_SECTION
-@item JUMP_TABLES_IN_TEXT_SECTION
+@defmac JUMP_TABLES_IN_TEXT_SECTION
Define this macro to be an expression with a nonzero value if jump
tables (for @code{tablejump} insns) should be output in the text
section, along with the assembler instructions. Otherwise, the
readonly data section is used.
This macro is irrelevant if there is no separate readonly data section.
+@end defmac
+
+@deftypefn {Target Hook} void TARGET_ASM_INIT_SECTIONS (void)
+Define this hook if you need to do something special to set up the
+@file{varasm.c} sections, or if your target has some special sections
+of its own that you need to create.
+
+GCC calls this hook after processing the command line, but before writing
+any assembly code, and before calling any of the section-returning hooks
+described below.
+@end deftypefn
+
+@deftypefn {Target Hook} TARGET_ASM_RELOC_RW_MASK (void)
+Return a mask describing how relocations should be treated when
+selecting sections. Bit 1 should be set if global relocations
+should be placed in a read-write section; bit 0 should be set if
+local relocations should be placed in a read-write section.
+
+The default version of this function returns 3 when @option{-fpic}
+is in effect, and 0 otherwise. The hook is typically redefined
+when the target cannot support (some kinds of) dynamic relocations
+in read-only sections even in executables.
+@end deftypefn
+
+@deftypefn {Target Hook} {section *} TARGET_ASM_SELECT_SECTION (tree @var{exp}, int @var{reloc}, unsigned HOST_WIDE_INT @var{align})
+Return the section into which @var{exp} should be placed. You can
+assume that @var{exp} is either a @code{VAR_DECL} node or a constant of
+some sort. @var{reloc} indicates whether the initial value of @var{exp}
+requires link-time relocations. Bit 0 is set when variable contains
+local relocations only, while bit 1 is set for global relocations.
+@var{align} is the constant alignment in bits.
+
+The default version of this function takes care of putting read-only
+variables in @code{readonly_data_section}.
+
+See also @var{USE_SELECT_SECTION_FOR_FUNCTIONS}.
+@end deftypefn
-@findex ENCODE_SECTION_INFO
-@item ENCODE_SECTION_INFO (@var{decl})
-Define this macro if references to a symbol or a constant must be
+@defmac USE_SELECT_SECTION_FOR_FUNCTIONS
+Define this macro if you wish TARGET_ASM_SELECT_SECTION to be called
+for @code{FUNCTION_DECL}s as well as for variables and constants.
+
+In the case of a @code{FUNCTION_DECL}, @var{reloc} will be zero if the
+function has been determined to be likely to be called, and nonzero if
+it is unlikely to be called.
+@end defmac
+
+@deftypefn {Target Hook} void TARGET_ASM_UNIQUE_SECTION (tree @var{decl}, int @var{reloc})
+Build up a unique section name, expressed as a @code{STRING_CST} node,
+and assign it to @samp{DECL_SECTION_NAME (@var{decl})}.
+As with @code{TARGET_ASM_SELECT_SECTION}, @var{reloc} indicates whether
+the initial value of @var{exp} requires link-time relocations.
+
+The default version of this function appends the symbol name to the
+ELF section name that would normally be used for the symbol. For
+example, the function @code{foo} would be placed in @code{.text.foo}.
+Whatever the actual target object format, this is often good enough.
+@end deftypefn
+
+@deftypefn {Target Hook} {section *} TARGET_ASM_FUNCTION_RODATA_SECTION (tree @var{decl})
+Return the readonly data section associated with
+@samp{DECL_SECTION_NAME (@var{decl})}.
+The default version of this function selects @code{.gnu.linkonce.r.name} if
+the function's section is @code{.gnu.linkonce.t.name}, @code{.rodata.name}
+if function is in @code{.text.name}, and the normal readonly-data section
+otherwise.
+@end deftypefn
+
+@deftypefn {Target Hook} {section *} TARGET_ASM_SELECT_RTX_SECTION (enum machine_mode @var{mode}, rtx @var{x}, unsigned HOST_WIDE_INT @var{align})
+Return the section into which a constant @var{x}, of mode @var{mode},
+should be placed. You can assume that @var{x} is some kind of
+constant in RTL@. The argument @var{mode} is redundant except in the
+case of a @code{const_int} rtx. @var{align} is the constant alignment
+in bits.
+
+The default version of this function takes care of putting symbolic
+constants in @code{flag_pic} mode in @code{data_section} and everything
+else in @code{readonly_data_section}.
+@end deftypefn
+
+@deftypefn {Target Hook} void TARGET_MANGLE_DECL_ASSEMBLER_NAME (tree @var{decl}, tree @var{id})
+Define this hook if you need to postprocess the assembler name generated
+by target-independent code. The @var{id} provided to this hook will be
+the computed name (e.g., the macro @code{DECL_NAME} of the @var{decl} in C,
+or the mangled name of the @var{decl} in C++). The return value of the
+hook is an @code{IDENTIFIER_NODE} for the appropriate mangled name on
+your target system. The default implementation of this hook just
+returns the @var{id} provided.
+@end deftypefn
+
+@deftypefn {Target Hook} void TARGET_ENCODE_SECTION_INFO (tree @var{decl}, rtx @var{rtl}, int @var{new_decl_p})
+Define this hook if references to a symbol or a constant must be
treated differently depending on something about the variable or
function named by the symbol (such as what section it is in).
-The macro definition, if any, is executed under two circumstances. One
-is immediately after the rtl for @var{decl} that represents a variable
-or a function has been created and stored in @code{DECL_RTL
-(@var{decl})}. The value of the rtl will be a @code{mem} whose address
-is a @code{symbol_ref}. The other is immediately after the rtl for
-@var{decl} that represents a constant has been created and stored in
-@code{TREE_CST_RTL (@var{decl})}. The macro is called once for each
-distinct constant in a source file.
-
-@cindex @code{SYMBOL_REF_FLAG}, in @code{ENCODE_SECTION_INFO}
-The usual thing for this macro to do is to record a flag in the
-@code{symbol_ref} (such as @code{SYMBOL_REF_FLAG}) or to store a
-modified name string in the @code{symbol_ref} (if one bit is not enough
-information).
-
-@findex STRIP_NAME_ENCODING
-@item STRIP_NAME_ENCODING (@var{var}, @var{sym_name})
-Decode @var{sym_name} and store the real name part in @var{var}, sans
-the characters that encode section info. Define this macro if
-@code{ENCODE_SECTION_INFO} alters the symbol's name string.
-
-@findex UNIQUE_SECTION
-@item UNIQUE_SECTION (@var{decl}, @var{reloc})
-A C statement to build up a unique section name, expressed as a
-@code{STRING_CST} node, and assign it to @samp{DECL_SECTION_NAME (@var{decl})}.
-@var{reloc} indicates whether the initial value of @var{exp} requires
-link-time relocations. If you do not define this macro, GCC will use
-the symbol name prefixed by @samp{.} as the section name. Note - this
-macro can now be called for uninitialized data items as well as
-initialized data and functions.
-@end table
+The hook is executed immediately after rtl has been created for
+@var{decl}, which may be a variable or function declaration or
+an entry in the constant pool. In either case, @var{rtl} is the
+rtl in question. Do @emph{not} use @code{DECL_RTL (@var{decl})}
+in this hook; that field may not have been initialized yet.
+
+In the case of a constant, it is safe to assume that the rtl is
+a @code{mem} whose address is a @code{symbol_ref}. Most decls
+will also have this form, but that is not guaranteed. Global
+register variables, for instance, will have a @code{reg} for their
+rtl. (Normally the right thing to do with such unusual rtl is
+leave it alone.)
+
+The @var{new_decl_p} argument will be true if this is the first time
+that @code{TARGET_ENCODE_SECTION_INFO} has been invoked on this decl. It will
+be false for subsequent invocations, which will happen for duplicate
+declarations. Whether or not anything must be done for the duplicate
+declaration depends on whether the hook examines @code{DECL_ATTRIBUTES}.
+@var{new_decl_p} is always true when the hook is called for a constant.
+
+@cindex @code{SYMBOL_REF_FLAG}, in @code{TARGET_ENCODE_SECTION_INFO}
+The usual thing for this hook to do is to record flags in the
+@code{symbol_ref}, using @code{SYMBOL_REF_FLAG} or @code{SYMBOL_REF_FLAGS}.
+Historically, the name string was modified if it was necessary to
+encode more than one bit of information, but this practice is now
+discouraged; use @code{SYMBOL_REF_FLAGS}.
+
+The default definition of this hook, @code{default_encode_section_info}
+in @file{varasm.c}, sets a number of commonly-useful bits in
+@code{SYMBOL_REF_FLAGS}. Check whether the default does what you need
+before overriding it.
+@end deftypefn
+
+@deftypefn {Target Hook} const char *TARGET_STRIP_NAME_ENCODING (const char *name)
+Decode @var{name} and return the real name part, sans
+the characters that @code{TARGET_ENCODE_SECTION_INFO}
+may have added.
+@end deftypefn
+
+@deftypefn {Target Hook} bool TARGET_IN_SMALL_DATA_P (tree @var{exp})
+Returns true if @var{exp} should be placed into a ``small data'' section.
+The default version of this hook always returns false.
+@end deftypefn
+
+@deftypevar {Target Hook} bool TARGET_HAVE_SRODATA_SECTION
+Contains the value true if the target places read-only
+``small data'' into a separate section. The default value is false.
+@end deftypevar
+
+@deftypefn {Target Hook} bool TARGET_BINDS_LOCAL_P (tree @var{exp})
+Returns true if @var{exp} names an object for which name resolution
+rules must resolve to the current ``module'' (dynamic shared library
+or executable image).
+
+The default version of this hook implements the name resolution rules
+for ELF, which has a looser model of global name binding than other
+currently supported object file formats.
+@end deftypefn
+
+@deftypevar {Target Hook} bool TARGET_HAVE_TLS
+Contains the value true if the target supports thread-local storage.
+The default value is false.
+@end deftypevar
+
@node PIC
@section Position Independent Code
@c i rearranged the order of the macros above to try to force one of
@c them to the next line, to eliminate an overfull hbox. --mew 10feb93
-@table @code
-@findex PIC_OFFSET_TABLE_REGNUM
-@item PIC_OFFSET_TABLE_REGNUM
+@defmac PIC_OFFSET_TABLE_REGNUM
The register number of the register used to address a table of static
data addresses in memory. In some cases this register is defined by a
processor's ``application binary interface'' (ABI)@. When this macro
is up to the machine-dependent files to allocate such a register (if
necessary). Note that this register must be fixed when in use (e.g.@:
when @code{flag_pic} is true).
+@end defmac
-@findex PIC_OFFSET_TABLE_REG_CALL_CLOBBERED
-@item PIC_OFFSET_TABLE_REG_CALL_CLOBBERED
+@defmac PIC_OFFSET_TABLE_REG_CALL_CLOBBERED
Define this macro if the register defined by
@code{PIC_OFFSET_TABLE_REGNUM} is clobbered by calls. Do not define
this macro if @code{PIC_OFFSET_TABLE_REGNUM} is not defined.
+@end defmac
-@findex FINALIZE_PIC
-@item FINALIZE_PIC
-By generating position-independent code, when two different programs (A
-and B) share a common library (libC.a), the text of the library can be
-shared whether or not the library is linked at the same address for both
-programs. In some of these environments, position-independent code
-requires not only the use of different addressing modes, but also
-special code to enable the use of these addressing modes.
-
-The @code{FINALIZE_PIC} macro serves as a hook to emit these special
-codes once the function is being compiled into assembly code, but not
-before. (It is not done before, because in the case of compiling an
-inline function, it would lead to multiple PIC prologues being
-included in functions which used inline functions and were compiled to
-assembly language.)
-
-@findex LEGITIMATE_PIC_OPERAND_P
-@item LEGITIMATE_PIC_OPERAND_P (@var{x})
+@defmac LEGITIMATE_PIC_OPERAND_P (@var{x})
A C expression that is nonzero if @var{x} is a legitimate immediate
operand on the target machine when generating position independent code.
You can assume that @var{x} satisfies @code{CONSTANT_P}, so you need not
check it either. You need not define this macro if all constants
(including @code{SYMBOL_REF}) can be immediate operands when generating
position independent code.
-@end table
+@end defmac
@node Assembler Format
@section Defining the Output Assembler Language
* Uninitialized Data:: Output of uninitialized variables.
* Label Output:: Output and generation of labels.
* Initialization:: General principles of initialization
- and termination routines.
+ and termination routines.
* Macros for Initialization::
- Specific macros that control the handling of
- initialization and termination routines.
+ Specific macros that control the handling of
+ initialization and termination routines.
* Instruction Output:: Output of actual instructions.
* Dispatch Tables:: Output of jump tables.
* Exception Region Output:: Output of exception region code.
@cindex output of assembler code
@c prevent bad page break with this line
-This describes the overall framework of an assembler file.
-
-@table @code
-@findex ASM_FILE_START
-@item ASM_FILE_START (@var{stream})
-A C expression which outputs to the stdio stream @var{stream}
-some appropriate text to go at the start of an assembler file.
-
-Normally this macro is defined to output a line containing
-@samp{#NO_APP}, which is a comment that has no effect on most
-assemblers but tells the GNU assembler that it can save time by not
-checking for certain assembler constructs.
+This describes the overall framework of an assembly file.
+
+@deftypefn {Target Hook} void TARGET_ASM_FILE_START ()
+@findex default_file_start
+Output to @code{asm_out_file} any text which the assembler expects to
+find at the beginning of a file. The default behavior is controlled
+by two flags, documented below. Unless your target's assembler is
+quite unusual, if you override the default, you should call
+@code{default_file_start} at some point in your target hook. This
+lets other target files rely on these variables.
+@end deftypefn
-On systems that use SDB, it is necessary to output certain commands;
-see @file{attasm.h}.
+@deftypevr {Target Hook} bool TARGET_ASM_FILE_START_APP_OFF
+If this flag is true, the text of the macro @code{ASM_APP_OFF} will be
+printed as the very first line in the assembly file, unless
+@option{-fverbose-asm} is in effect. (If that macro has been defined
+to the empty string, this variable has no effect.) With the normal
+definition of @code{ASM_APP_OFF}, the effect is to notify the GNU
+assembler that it need not bother stripping comments or extra
+whitespace from its input. This allows it to work a bit faster.
+
+The default is false. You should not set it to true unless you have
+verified that your port does not generate any extra whitespace or
+comments that will cause GAS to issue errors in NO_APP mode.
+@end deftypevr
-@findex ASM_FILE_END
-@item ASM_FILE_END (@var{stream})
-A C expression which outputs to the stdio stream @var{stream}
-some appropriate text to go at the end of an assembler file.
+@deftypevr {Target Hook} bool TARGET_ASM_FILE_START_FILE_DIRECTIVE
+If this flag is true, @code{output_file_directive} will be called
+for the primary source file, immediately after printing
+@code{ASM_APP_OFF} (if that is enabled). Most ELF assemblers expect
+this to be done. The default is false.
+@end deftypevr
-If this macro is not defined, the default is to output nothing
-special at the end of the file. Most systems don't require any
-definition.
+@deftypefn {Target Hook} void TARGET_ASM_FILE_END ()
+Output to @code{asm_out_file} any text which the assembler expects
+to find at the end of a file. The default is to output nothing.
+@end deftypefn
-On systems that use SDB, it is necessary to output certain commands;
-see @file{attasm.h}.
+@deftypefun void file_end_indicate_exec_stack ()
+Some systems use a common convention, the @samp{.note.GNU-stack}
+special section, to indicate whether or not an object file relies on
+the stack being executable. If your system uses this convention, you
+should define @code{TARGET_ASM_FILE_END} to this function. If you
+need to do other things in that hook, have your hook function call
+this function.
+@end deftypefun
-@findex ASM_COMMENT_START
-@item ASM_COMMENT_START
+@defmac ASM_COMMENT_START
A C string constant describing how to begin a comment in the target
assembler language. The compiler assumes that the comment will end at
the end of the line.
+@end defmac
-@findex ASM_APP_ON
-@item ASM_APP_ON
+@defmac ASM_APP_ON
A C string constant for text to be output before each @code{asm}
statement or group of consecutive ones. Normally this is
@code{"#APP"}, which is a comment that has no effect on most
assemblers but tells the GNU assembler that it must check the lines
that follow for all valid assembler constructs.
+@end defmac
-@findex ASM_APP_OFF
-@item ASM_APP_OFF
+@defmac ASM_APP_OFF
A C string constant for text to be output after each @code{asm}
statement or group of consecutive ones. Normally this is
@code{"#NO_APP"}, which tells the GNU assembler to resume making the
time-saving assumptions that are valid for ordinary compiler output.
+@end defmac
-@findex ASM_OUTPUT_SOURCE_FILENAME
-@item ASM_OUTPUT_SOURCE_FILENAME (@var{stream}, @var{name})
+@defmac ASM_OUTPUT_SOURCE_FILENAME (@var{stream}, @var{name})
A C statement to output COFF information or DWARF debugging information
which indicates that filename @var{name} is the current source file to
the stdio stream @var{stream}.
This macro need not be defined if the standard form of output
for the file format in use is appropriate.
+@end defmac
-@findex OUTPUT_QUOTED_STRING
-@item OUTPUT_QUOTED_STRING (@var{stream}, @var{string})
+@defmac OUTPUT_QUOTED_STRING (@var{stream}, @var{string})
A C statement to output the string @var{string} to the stdio stream
@var{stream}. If you do not call the function @code{output_quoted_string}
in your config files, GCC will only call it to output filenames to
the assembler source. So you can use it to canonicalize the format
of the filename using this macro.
+@end defmac
-@findex ASM_OUTPUT_SOURCE_LINE
-@item ASM_OUTPUT_SOURCE_LINE (@var{stream}, @var{line})
-A C statement to output DBX or SDB debugging information before code
-for line number @var{line} of the current source file to the
-stdio stream @var{stream}.
-
-This macro need not be defined if the standard form of debugging
-information for the debugger in use is appropriate.
-
-@findex ASM_OUTPUT_IDENT
-@item ASM_OUTPUT_IDENT (@var{stream}, @var{string})
+@defmac ASM_OUTPUT_IDENT (@var{stream}, @var{string})
A C statement to output something to the assembler file to handle a
@samp{#ident} directive containing the text @var{string}. If this
macro is not defined, nothing is output for a @samp{#ident} directive.
-
-@findex OBJC_PROLOGUE
-@item OBJC_PROLOGUE
-A C statement to output any assembler statements which are required to
-precede any Objective-C object definitions or message sending. The
-statement is executed only when compiling an Objective-C program.
-@end table
+@end defmac
@deftypefn {Target Hook} void TARGET_ASM_NAMED_SECTION (const char *@var{name}, unsigned int @var{flags}, unsigned int @var{align})
Output assembly directives to switch to section @var{name}. The section
This flag is true if the target supports @code{TARGET_ASM_NAMED_SECTION}.
@end deftypefn
+@anchor{TARGET_HAVE_SWITCHABLE_BSS_SECTIONS}
+@deftypefn {Target Hook} bool TARGET_HAVE_SWITCHABLE_BSS_SECTIONS
+This flag is true if we can create zeroed data by switching to a BSS
+section and then using @code{ASM_OUTPUT_SKIP} to allocate the space.
+This is true on most ELF targets.
+@end deftypefn
+
@deftypefn {Target Hook} {unsigned int} TARGET_SECTION_TYPE_FLAGS (tree @var{decl}, const char *@var{name}, int @var{reloc})
Choose a set of section attributes for use by @code{TARGET_ASM_NAMED_SECTION}
based on a variable or function decl, a section name, and whether or not the
declaration's initializer may contain runtime relocations. @var{decl} may be
- null, in which case read-write data should be assumed.
+null, in which case read-write data should be assumed.
-The default version if this function handles choosing code vs data,
+The default version of this function handles choosing code vs data,
read-only vs read-write data, and @code{flag_pic}. You should only
need to override this if your target has special flags that might be
set via @code{__attribute__}.
@end deftypefn
+@deftypefn {Target Hook} {int} TARGET_ASM_RECORD_GCC_SWITCHES (print_switch_type @var{type}, const char * @var{text})
+Provides the target with the ability to record the gcc command line
+switches that have been passed to the compiler, and options that are
+enabled. The @var{type} argument specifies what is being recorded.
+It can take the following values:
+
+@table @gcctabopt
+@item SWITCH_TYPE_PASSED
+@var{text} is a command line switch that has been set by the user.
+
+@item SWITCH_TYPE_ENABLED
+@var{text} is an option which has been enabled. This might be as a
+direct result of a command line switch, or because it is enabled by
+default or because it has been enabled as a side effect of a different
+command line switch. For example, the @option{-O2} switch enables
+various different individual optimization passes.
+
+@item SWITCH_TYPE_DESCRIPTIVE
+@var{text} is either NULL or some descriptive text which should be
+ignored. If @var{text} is NULL then it is being used to warn the
+target hook that either recording is starting or ending. The first
+time @var{type} is SWITCH_TYPE_DESCRIPTIVE and @var{text} is NULL, the
+warning is for start up and the second time the warning is for
+wind down. This feature is to allow the target hook to make any
+necessary preparations before it starts to record switches and to
+perform any necessary tidying up after it has finished recording
+switches.
+
+@item SWITCH_TYPE_LINE_START
+This option can be ignored by this target hook.
+
+@item SWITCH_TYPE_LINE_END
+This option can be ignored by this target hook.
+@end table
+
+The hook's return value must be zero. Other return values may be
+supported in the future.
+
+By default this hook is set to NULL, but an example implementation is
+provided for ELF based targets. Called @var{elf_record_gcc_switches},
+it records the switches as ASCII text inside a new, string mergeable
+section in the assembler output file. The name of the new section is
+provided by the @code{TARGET_ASM_RECORD_GCC_SWITCHES_SECTION} target
+hook.
+@end deftypefn
+
+@deftypefn {Target Hook} {const char *} TARGET_ASM_RECORD_GCC_SWITCHES_SECTION
+This is the name of the section that will be created by the example
+ELF implementation of the @code{TARGET_ASM_RECORD_GCC_SWITCHES} target
+hook.
+@end deftypefn
+
@need 2000
@node Data Output
@subsection Output of Data
when the relevant string is @code{NULL}.
@end deftypefn
-@table @code
-@findex OUTPUT_ADDR_CONST_EXTRA
-@item OUTPUT_ADDR_CONST_EXTRA (@var{stream}, @var{x}, @var{fail})
+@defmac OUTPUT_ADDR_CONST_EXTRA (@var{stream}, @var{x}, @var{fail})
A C statement to recognize @var{rtx} patterns that
@code{output_addr_const} can't deal with, and output assembly code to
@var{stream} corresponding to the pattern @var{x}. This may be used to
@code{goto fail}, so that a standard error message is printed. If it
prints an error message itself, by calling, for example,
@code{output_operand_lossage}, it may just complete normally.
+@end defmac
-@findex ASM_OUTPUT_ASCII
-@item ASM_OUTPUT_ASCII (@var{stream}, @var{ptr}, @var{len})
+@defmac ASM_OUTPUT_ASCII (@var{stream}, @var{ptr}, @var{len})
A C statement to output to the stdio stream @var{stream} an assembler
instruction to assemble a string constant containing the @var{len}
bytes at @var{ptr}. @var{ptr} will be a C expression of type
If the assembler has a @code{.ascii} pseudo-op as found in the
Berkeley Unix assembler, do not define the macro
@code{ASM_OUTPUT_ASCII}.
+@end defmac
-@findex ASM_OUTPUT_FDESC
-@item ASM_OUTPUT_FDESC (@var{stream}, @var{decl}, @var{n})
+@defmac ASM_OUTPUT_FDESC (@var{stream}, @var{decl}, @var{n})
A C statement to output word @var{n} of a function descriptor for
@var{decl}. This must be defined if @code{TARGET_VTABLE_USES_DESCRIPTORS}
is defined, and is otherwise unused.
+@end defmac
-@findex CONSTANT_POOL_BEFORE_FUNCTION
-@item CONSTANT_POOL_BEFORE_FUNCTION
+@defmac CONSTANT_POOL_BEFORE_FUNCTION
You may define this macro as a C expression. You should define the
expression to have a nonzero value if GCC should output the constant
pool for a function before the code for the function, or a zero value if
GCC should output the constant pool after the function. If you do
not define this macro, the usual case, GCC will output the constant
pool before the function.
+@end defmac
-@findex ASM_OUTPUT_POOL_PROLOGUE
-@item ASM_OUTPUT_POOL_PROLOGUE (@var{file}, @var{funname}, @var{fundecl}, @var{size})
+@defmac ASM_OUTPUT_POOL_PROLOGUE (@var{file}, @var{funname}, @var{fundecl}, @var{size})
A C statement to output assembler commands to define the start of the
constant pool for a function. @var{funname} is a string giving
the name of the function. Should the return type of the function
If no constant-pool prefix is required, the usual case, this macro need
not be defined.
+@end defmac
-@findex ASM_OUTPUT_SPECIAL_POOL_ENTRY
-@item ASM_OUTPUT_SPECIAL_POOL_ENTRY (@var{file}, @var{x}, @var{mode}, @var{align}, @var{labelno}, @var{jumpto})
+@defmac ASM_OUTPUT_SPECIAL_POOL_ENTRY (@var{file}, @var{x}, @var{mode}, @var{align}, @var{labelno}, @var{jumpto})
A C statement (with or without semicolon) to output a constant in the
constant pool, if it needs special treatment. (This macro need not do
anything for RTL expressions that can be output normally.)
responsible for outputting the label definition at the proper place.
Here is how to do this:
-@example
-ASM_OUTPUT_INTERNAL_LABEL (@var{file}, "LC", @var{labelno});
-@end example
+@smallexample
+@code{(*targetm.asm_out.internal_label)} (@var{file}, "LC", @var{labelno});
+@end smallexample
When you output a pool entry specially, you should end with a
@code{goto} to the label @var{jumpto}. This will prevent the same pool
entry from being output a second time in the usual manner.
You need not define this macro if it would do nothing.
+@end defmac
-@findex CONSTANT_AFTER_FUNCTION_P
-@item CONSTANT_AFTER_FUNCTION_P (@var{exp})
-Define this macro as a C expression which is nonzero if the constant
-@var{exp}, of type @code{tree}, should be output after the code for a
-function. The compiler will normally output all constants before the
-function; you need not define this macro if this is OK@.
-
-@findex ASM_OUTPUT_POOL_EPILOGUE
-@item ASM_OUTPUT_POOL_EPILOGUE (@var{file} @var{funname} @var{fundecl} @var{size})
+@defmac ASM_OUTPUT_POOL_EPILOGUE (@var{file} @var{funname} @var{fundecl} @var{size})
A C statement to output assembler commands to at the end of the constant
pool for a function. @var{funname} is a string giving the name of the
function. Should the return type of the function be required, you can
If no constant-pool epilogue is required, the usual case, you need not
define this macro.
+@end defmac
-@findex IS_ASM_LOGICAL_LINE_SEPARATOR
-@item IS_ASM_LOGICAL_LINE_SEPARATOR (@var{C})
+@defmac IS_ASM_LOGICAL_LINE_SEPARATOR (@var{C}, @var{STR})
Define this macro as a C expression which is nonzero if @var{C} is
-used as a logical line separator by the assembler.
+used as a logical line separator by the assembler. @var{STR} points
+to the position in the string where @var{C} was found; this can be used if
+a line separator uses multiple characters.
If you do not define this macro, the default is that only
the character @samp{;} is treated as a logical line separator.
-@end table
+@end defmac
@deftypevr {Target Hook} {const char *} TARGET_ASM_OPEN_PAREN
@deftypevrx {Target Hook} {const char *} TARGET_ASM_CLOSE_PAREN
default to normal parentheses, which is correct for most assemblers.
@end deftypevr
- These macros are provided by @file{real.h} for writing the definitions
+These macros are provided by @file{real.h} for writing the definitions
of @code{ASM_OUTPUT_DOUBLE} and the like:
-@table @code
-@item REAL_VALUE_TO_TARGET_SINGLE (@var{x}, @var{l})
-@itemx REAL_VALUE_TO_TARGET_DOUBLE (@var{x}, @var{l})
-@itemx REAL_VALUE_TO_TARGET_LONG_DOUBLE (@var{x}, @var{l})
-@findex REAL_VALUE_TO_TARGET_SINGLE
-@findex REAL_VALUE_TO_TARGET_DOUBLE
-@findex REAL_VALUE_TO_TARGET_LONG_DOUBLE
-These translate @var{x}, of type @code{REAL_VALUE_TYPE}, to the target's
-floating point representation, and store its bit pattern in the array of
-@code{long int} whose address is @var{l}. The number of elements in the
-output array is determined by the size of the desired target floating
-point data type: 32 bits of it go in each @code{long int} array
-element. Each array element holds 32 bits of the result, even if
-@code{long int} is wider than 32 bits on the host machine.
+@defmac REAL_VALUE_TO_TARGET_SINGLE (@var{x}, @var{l})
+@defmacx REAL_VALUE_TO_TARGET_DOUBLE (@var{x}, @var{l})
+@defmacx REAL_VALUE_TO_TARGET_LONG_DOUBLE (@var{x}, @var{l})
+@defmacx REAL_VALUE_TO_TARGET_DECIMAL32 (@var{x}, @var{l})
+@defmacx REAL_VALUE_TO_TARGET_DECIMAL64 (@var{x}, @var{l})
+@defmacx REAL_VALUE_TO_TARGET_DECIMAL128 (@var{x}, @var{l})
+These translate @var{x}, of type @code{REAL_VALUE_TYPE}, to the
+target's floating point representation, and store its bit pattern in
+the variable @var{l}. For @code{REAL_VALUE_TO_TARGET_SINGLE} and
+@code{REAL_VALUE_TO_TARGET_DECIMAL32}, this variable should be a
+simple @code{long int}. For the others, it should be an array of
+@code{long int}. The number of elements in this array is determined
+by the size of the desired target floating point data type: 32 bits of
+it go in each @code{long int} array element. Each array element holds
+32 bits of the result, even if @code{long int} is wider than 32 bits
+on the host machine.
The array element values are designed so that you can print them out
using @code{fprintf} in the order they should appear in the target
machine's memory.
-
-@item REAL_VALUE_TO_DECIMAL (@var{x}, @var{format}, @var{string})
-@findex REAL_VALUE_TO_DECIMAL
-This macro converts @var{x}, of type @code{REAL_VALUE_TYPE}, to a
-decimal number and stores it as a string into @var{string}.
-You must pass, as @var{string}, the address of a long enough block
-of space to hold the result.
-
-The argument @var{format} is a @code{printf}-specification that serves
-as a suggestion for how to format the output string.
-@end table
+@end defmac
@node Uninitialized Data
@subsection Output of Uninitialized Variables
Each of the macros in this section is used to do the whole job of
outputting a single uninitialized variable.
-@table @code
-@findex ASM_OUTPUT_COMMON
-@item ASM_OUTPUT_COMMON (@var{stream}, @var{name}, @var{size}, @var{rounded})
+@defmac ASM_OUTPUT_COMMON (@var{stream}, @var{name}, @var{size}, @var{rounded})
A C statement (sans semicolon) to output to the stdio stream
@var{stream} the assembler definition of a common-label named
@var{name} whose size is @var{size} bytes. The variable @var{rounded}
This macro controls how the assembler definitions of uninitialized
common global variables are output.
+@end defmac
-@findex ASM_OUTPUT_ALIGNED_COMMON
-@item ASM_OUTPUT_ALIGNED_COMMON (@var{stream}, @var{name}, @var{size}, @var{alignment})
+@defmac ASM_OUTPUT_ALIGNED_COMMON (@var{stream}, @var{name}, @var{size}, @var{alignment})
Like @code{ASM_OUTPUT_COMMON} except takes the required alignment as a
separate, explicit argument. If you define this macro, it is used in
place of @code{ASM_OUTPUT_COMMON}, and gives you more flexibility in
handling the required alignment of the variable. The alignment is specified
as the number of bits.
+@end defmac
-@findex ASM_OUTPUT_ALIGNED_DECL_COMMON
-@item ASM_OUTPUT_ALIGNED_DECL_COMMON (@var{stream}, @var{decl}, @var{name}, @var{size}, @var{alignment})
+@defmac ASM_OUTPUT_ALIGNED_DECL_COMMON (@var{stream}, @var{decl}, @var{name}, @var{size}, @var{alignment})
Like @code{ASM_OUTPUT_ALIGNED_COMMON} except that @var{decl} of the
variable to be output, if there is one, or @code{NULL_TREE} if there
is no corresponding variable. If you define this macro, GCC will use it
in place of both @code{ASM_OUTPUT_COMMON} and
@code{ASM_OUTPUT_ALIGNED_COMMON}. Define this macro when you need to see
the variable's decl in order to chose what to output.
+@end defmac
-@findex ASM_OUTPUT_SHARED_COMMON
-@item ASM_OUTPUT_SHARED_COMMON (@var{stream}, @var{name}, @var{size}, @var{rounded})
-If defined, it is similar to @code{ASM_OUTPUT_COMMON}, except that it
-is used when @var{name} is shared. If not defined, @code{ASM_OUTPUT_COMMON}
-will be used.
-
-@findex ASM_OUTPUT_BSS
-@item ASM_OUTPUT_BSS (@var{stream}, @var{decl}, @var{name}, @var{size}, @var{rounded})
+@defmac ASM_OUTPUT_BSS (@var{stream}, @var{decl}, @var{name}, @var{size}, @var{rounded})
A C statement (sans semicolon) to output to the stdio stream
@var{stream} the assembler definition of uninitialized global @var{decl} named
@var{name} whose size is @var{size} bytes. The variable @var{rounded}
before and after that, output the additional assembler syntax for defining
the name, and a newline.
-This macro controls how the assembler definitions of uninitialized global
-variables are output. This macro exists to properly support languages like
-C++ which do not have @code{common} data. However, this macro currently
-is not defined for all targets. If this macro and
-@code{ASM_OUTPUT_ALIGNED_BSS} are not defined then @code{ASM_OUTPUT_COMMON}
-or @code{ASM_OUTPUT_ALIGNED_COMMON} or
-@code{ASM_OUTPUT_ALIGNED_DECL_COMMON} is used.
+There are two ways of handling global BSS@. One is to define either
+this macro or its aligned counterpart, @code{ASM_OUTPUT_ALIGNED_BSS}.
+The other is to have @code{TARGET_ASM_SELECT_SECTION} return a
+switchable BSS section (@pxref{TARGET_HAVE_SWITCHABLE_BSS_SECTIONS}).
+You do not need to do both.
-@findex ASM_OUTPUT_ALIGNED_BSS
-@item ASM_OUTPUT_ALIGNED_BSS (@var{stream}, @var{decl}, @var{name}, @var{size}, @var{alignment})
+Some languages do not have @code{common} data, and require a
+non-common form of global BSS in order to handle uninitialized globals
+efficiently. C++ is one example of this. However, if the target does
+not support global BSS, the front end may choose to make globals
+common in order to save space in the object file.
+@end defmac
+
+@defmac ASM_OUTPUT_ALIGNED_BSS (@var{stream}, @var{decl}, @var{name}, @var{size}, @var{alignment})
Like @code{ASM_OUTPUT_BSS} except takes the required alignment as a
separate, explicit argument. If you define this macro, it is used in
place of @code{ASM_OUTPUT_BSS}, and gives you more flexibility in
Try to use function @code{asm_output_aligned_bss} defined in file
@file{varasm.c} when defining this macro.
+@end defmac
-@findex ASM_OUTPUT_SHARED_BSS
-@item ASM_OUTPUT_SHARED_BSS (@var{stream}, @var{decl}, @var{name}, @var{size}, @var{rounded})
-If defined, it is similar to @code{ASM_OUTPUT_BSS}, except that it
-is used when @var{name} is shared. If not defined, @code{ASM_OUTPUT_BSS}
-will be used.
-
-@findex ASM_OUTPUT_LOCAL
-@item ASM_OUTPUT_LOCAL (@var{stream}, @var{name}, @var{size}, @var{rounded})
+@defmac ASM_OUTPUT_LOCAL (@var{stream}, @var{name}, @var{size}, @var{rounded})
A C statement (sans semicolon) to output to the stdio stream
@var{stream} the assembler definition of a local-common-label named
@var{name} whose size is @var{size} bytes. The variable @var{rounded}
This macro controls how the assembler definitions of uninitialized
static variables are output.
+@end defmac
-@findex ASM_OUTPUT_ALIGNED_LOCAL
-@item ASM_OUTPUT_ALIGNED_LOCAL (@var{stream}, @var{name}, @var{size}, @var{alignment})
+@defmac ASM_OUTPUT_ALIGNED_LOCAL (@var{stream}, @var{name}, @var{size}, @var{alignment})
Like @code{ASM_OUTPUT_LOCAL} except takes the required alignment as a
separate, explicit argument. If you define this macro, it is used in
place of @code{ASM_OUTPUT_LOCAL}, and gives you more flexibility in
handling the required alignment of the variable. The alignment is specified
as the number of bits.
+@end defmac
-@findex ASM_OUTPUT_ALIGNED_DECL_LOCAL
-@item ASM_OUTPUT_ALIGNED_DECL_LOCAL (@var{stream}, @var{decl}, @var{name}, @var{size}, @var{alignment})
+@defmac ASM_OUTPUT_ALIGNED_DECL_LOCAL (@var{stream}, @var{decl}, @var{name}, @var{size}, @var{alignment})
Like @code{ASM_OUTPUT_ALIGNED_DECL} except that @var{decl} of the
variable to be output, if there is one, or @code{NULL_TREE} if there
is no corresponding variable. If you define this macro, GCC will use it
in place of both @code{ASM_OUTPUT_DECL} and
@code{ASM_OUTPUT_ALIGNED_DECL}. Define this macro when you need to see
the variable's decl in order to chose what to output.
-
-@findex ASM_OUTPUT_SHARED_LOCAL
-@item ASM_OUTPUT_SHARED_LOCAL (@var{stream}, @var{name}, @var{size}, @var{rounded})
-If defined, it is similar to @code{ASM_OUTPUT_LOCAL}, except that it
-is used when @var{name} is shared. If not defined, @code{ASM_OUTPUT_LOCAL}
-will be used.
-@end table
+@end defmac
@node Label Output
@subsection Output and Generation of Labels
@c prevent bad page break with this line
This is about outputting labels.
-@table @code
-@findex ASM_OUTPUT_LABEL
@findex assemble_name
-@item ASM_OUTPUT_LABEL (@var{stream}, @var{name})
+@defmac ASM_OUTPUT_LABEL (@var{stream}, @var{name})
A C statement (sans semicolon) to output to the stdio stream
@var{stream} the assembler definition of a label named @var{name}.
Use the expression @code{assemble_name (@var{stream}, @var{name})} to
output the name itself; before and after that, output the additional
-assembler syntax for defining the name, and a newline.
+assembler syntax for defining the name, and a newline. A default
+definition of this macro is provided which is correct for most systems.
+@end defmac
+
+@findex assemble_name_raw
+@defmac ASM_OUTPUT_INTERNAL_LABEL (@var{stream}, @var{name})
+Identical to @code{ASM_OUTPUT_LABEL}, except that @var{name} is known
+to refer to a compiler-generated label. The default definition uses
+@code{assemble_name_raw}, which is like @code{assemble_name} except
+that it is more efficient.
+@end defmac
+
+@defmac SIZE_ASM_OP
+A C string containing the appropriate assembler directive to specify the
+size of a symbol, without any arguments. On systems that use ELF, the
+default (in @file{config/elfos.h}) is @samp{"\t.size\t"}; on other
+systems, the default is not to define this macro.
+
+Define this macro only if it is correct to use the default definitions
+of @code{ASM_OUTPUT_SIZE_DIRECTIVE} and @code{ASM_OUTPUT_MEASURED_SIZE}
+for your system. If you need your own custom definitions of those
+macros, or if you do not need explicit symbol sizes at all, do not
+define this macro.
+@end defmac
+
+@defmac ASM_OUTPUT_SIZE_DIRECTIVE (@var{stream}, @var{name}, @var{size})
+A C statement (sans semicolon) to output to the stdio stream
+@var{stream} a directive telling the assembler that the size of the
+symbol @var{name} is @var{size}. @var{size} is a @code{HOST_WIDE_INT}.
+If you define @code{SIZE_ASM_OP}, a default definition of this macro is
+provided.
+@end defmac
+
+@defmac ASM_OUTPUT_MEASURED_SIZE (@var{stream}, @var{name})
+A C statement (sans semicolon) to output to the stdio stream
+@var{stream} a directive telling the assembler to calculate the size of
+the symbol @var{name} by subtracting its address from the current
+address.
+
+If you define @code{SIZE_ASM_OP}, a default definition of this macro is
+provided. The default assumes that the assembler recognizes a special
+@samp{.} symbol as referring to the current address, and can calculate
+the difference between this and another symbol. If your assembler does
+not recognize @samp{.} or cannot do calculations with it, you will need
+to redefine @code{ASM_OUTPUT_MEASURED_SIZE} to use some other technique.
+@end defmac
+
+@defmac TYPE_ASM_OP
+A C string containing the appropriate assembler directive to specify the
+type of a symbol, without any arguments. On systems that use ELF, the
+default (in @file{config/elfos.h}) is @samp{"\t.type\t"}; on other
+systems, the default is not to define this macro.
+
+Define this macro only if it is correct to use the default definition of
+@code{ASM_OUTPUT_TYPE_DIRECTIVE} for your system. If you need your own
+custom definition of this macro, or if you do not need explicit symbol
+types at all, do not define this macro.
+@end defmac
+
+@defmac TYPE_OPERAND_FMT
+A C string which specifies (using @code{printf} syntax) the format of
+the second operand to @code{TYPE_ASM_OP}. On systems that use ELF, the
+default (in @file{config/elfos.h}) is @samp{"@@%s"}; on other systems,
+the default is not to define this macro.
+
+Define this macro only if it is correct to use the default definition of
+@code{ASM_OUTPUT_TYPE_DIRECTIVE} for your system. If you need your own
+custom definition of this macro, or if you do not need explicit symbol
+types at all, do not define this macro.
+@end defmac
+
+@defmac ASM_OUTPUT_TYPE_DIRECTIVE (@var{stream}, @var{type})
+A C statement (sans semicolon) to output to the stdio stream
+@var{stream} a directive telling the assembler that the type of the
+symbol @var{name} is @var{type}. @var{type} is a C string; currently,
+that string is always either @samp{"function"} or @samp{"object"}, but
+you should not count on this.
-@findex ASM_DECLARE_FUNCTION_NAME
-@item ASM_DECLARE_FUNCTION_NAME (@var{stream}, @var{name}, @var{decl})
+If you define @code{TYPE_ASM_OP} and @code{TYPE_OPERAND_FMT}, a default
+definition of this macro is provided.
+@end defmac
+
+@defmac ASM_DECLARE_FUNCTION_NAME (@var{stream}, @var{name}, @var{decl})
A C statement (sans semicolon) to output to the stdio stream
@var{stream} any text necessary for declaring the name @var{name} of a
function which is being defined. This macro is responsible for
If this macro is not defined, then the function name is defined in the
usual manner as a label (by means of @code{ASM_OUTPUT_LABEL}).
-@findex ASM_DECLARE_FUNCTION_SIZE
-@item ASM_DECLARE_FUNCTION_SIZE (@var{stream}, @var{name}, @var{decl})
+You may wish to use @code{ASM_OUTPUT_TYPE_DIRECTIVE} in the definition
+of this macro.
+@end defmac
+
+@defmac ASM_DECLARE_FUNCTION_SIZE (@var{stream}, @var{name}, @var{decl})
A C statement (sans semicolon) to output to the stdio stream
@var{stream} any text necessary for declaring the size of a function
which is being defined. The argument @var{name} is the name of the
If this macro is not defined, then the function size is not defined.
-@findex ASM_DECLARE_OBJECT_NAME
-@item ASM_DECLARE_OBJECT_NAME (@var{stream}, @var{name}, @var{decl})
+You may wish to use @code{ASM_OUTPUT_MEASURED_SIZE} in the definition
+of this macro.
+@end defmac
+
+@defmac ASM_DECLARE_OBJECT_NAME (@var{stream}, @var{name}, @var{decl})
A C statement (sans semicolon) to output to the stdio stream
@var{stream} any text necessary for declaring the name @var{name} of an
initialized variable which is being defined. This macro must output the
If this macro is not defined, then the variable name is defined in the
usual manner as a label (by means of @code{ASM_OUTPUT_LABEL}).
-@findex ASM_DECLARE_REGISTER_GLOBAL
-@item ASM_DECLARE_REGISTER_GLOBAL (@var{stream}, @var{decl}, @var{regno}, @var{name})
+You may wish to use @code{ASM_OUTPUT_TYPE_DIRECTIVE} and/or
+@code{ASM_OUTPUT_SIZE_DIRECTIVE} in the definition of this macro.
+@end defmac
+
+@defmac ASM_DECLARE_CONSTANT_NAME (@var{stream}, @var{name}, @var{exp}, @var{size})
+A C statement (sans semicolon) to output to the stdio stream
+@var{stream} any text necessary for declaring the name @var{name} of a
+constant which is being defined. This macro is responsible for
+outputting the label definition (perhaps using
+@code{ASM_OUTPUT_LABEL}). The argument @var{exp} is the
+value of the constant, and @var{size} is the size of the constant
+in bytes. @var{name} will be an internal label.
+
+If this macro is not defined, then the @var{name} is defined in the
+usual manner as a label (by means of @code{ASM_OUTPUT_LABEL}).
+
+You may wish to use @code{ASM_OUTPUT_TYPE_DIRECTIVE} in the definition
+of this macro.
+@end defmac
+
+@defmac ASM_DECLARE_REGISTER_GLOBAL (@var{stream}, @var{decl}, @var{regno}, @var{name})
A C statement (sans semicolon) to output to the stdio stream
@var{stream} any text necessary for claiming a register @var{regno}
for a global variable @var{decl} with name @var{name}.
If you don't define this macro, that is equivalent to defining it to do
nothing.
+@end defmac
-@findex ASM_FINISH_DECLARE_OBJECT
-@item ASM_FINISH_DECLARE_OBJECT (@var{stream}, @var{decl}, @var{toplevel}, @var{atend})
+@defmac ASM_FINISH_DECLARE_OBJECT (@var{stream}, @var{decl}, @var{toplevel}, @var{atend})
A C statement (sans semicolon) to finish up declaring a variable name
once the compiler has processed its initializer fully and thus has had a
chance to determine the size of an array when controlled by an
If you don't define this macro, that is equivalent to defining it to do
nothing.
-@findex ASM_GLOBALIZE_LABEL
-@item ASM_GLOBALIZE_LABEL (@var{stream}, @var{name})
-A C statement (sans semicolon) to output to the stdio stream
+You may wish to use @code{ASM_OUTPUT_SIZE_DIRECTIVE} and/or
+@code{ASM_OUTPUT_MEASURED_SIZE} in the definition of this macro.
+@end defmac
+
+@deftypefn {Target Hook} void TARGET_ASM_GLOBALIZE_LABEL (FILE *@var{stream}, const char *@var{name})
+This target hook is a function to output to the stdio stream
@var{stream} some commands that will make the label @var{name} global;
-that is, available for reference from other files. Use the expression
-@code{assemble_name (@var{stream}, @var{name})} to output the name
-itself; before and after that, output the additional assembler syntax
-for making that name global, and a newline.
+that is, available for reference from other files.
+
+The default implementation relies on a proper definition of
+@code{GLOBAL_ASM_OP}.
+@end deftypefn
+
+@deftypefn {Target Hook} void TARGET_ASM_GLOBALIZE_DECL_NAME (FILE *@var{stream}, tree @var{decl})
+This target hook is a function to output to the stdio stream
+@var{stream} some commands that will make the name associated with @var{decl}
+global; that is, available for reference from other files.
+
+The default implementation uses the TARGET_ASM_GLOBALIZE_LABEL target hook.
+@end deftypefn
-@findex ASM_WEAKEN_LABEL
-@item ASM_WEAKEN_LABEL (@var{stream}, @var{name})
+@defmac ASM_WEAKEN_LABEL (@var{stream}, @var{name})
A C statement (sans semicolon) to output to the stdio stream
@var{stream} some commands that will make the label @var{name} weak;
that is, available for reference from other files but only used if
If you don't define this macro or @code{ASM_WEAKEN_DECL}, GCC will not
support weak symbols and you should not define the @code{SUPPORTS_WEAK}
macro.
+@end defmac
-@findex ASM_WEAKEN_DECL
-@item ASM_WEAKEN_DECL (@var{stream}, @var{decl}, @var{name}, @var{value})
+@defmac ASM_WEAKEN_DECL (@var{stream}, @var{decl}, @var{name}, @var{value})
Combines (and replaces) the function of @code{ASM_WEAKEN_LABEL} and
@code{ASM_OUTPUT_WEAK_ALIAS}, allowing access to the associated function
or variable decl. If @var{value} is not @code{NULL}, this C statement
defines (equates) the weak symbol @var{name} to have the value
@var{value}. If @var{value} is @code{NULL}, it should output commands
to make @var{name} weak.
+@end defmac
-@findex SUPPORTS_WEAK
-@item SUPPORTS_WEAK
+@defmac ASM_OUTPUT_WEAKREF (@var{stream}, @var{decl}, @var{name}, @var{value})
+Outputs a directive that enables @var{name} to be used to refer to
+symbol @var{value} with weak-symbol semantics. @code{decl} is the
+declaration of @code{name}.
+@end defmac
+
+@defmac SUPPORTS_WEAK
A C expression which evaluates to true if the target supports weak symbols.
If you don't define this macro, @file{defaults.h} provides a default
is defined, the default definition is @samp{1}; otherwise, it is
@samp{0}. Define this macro if you want to control weak symbol support
with a compiler flag such as @option{-melf}.
+@end defmac
-@findex MAKE_DECL_ONE_ONLY (@var{decl})
-@item MAKE_DECL_ONE_ONLY
+@defmac MAKE_DECL_ONE_ONLY (@var{decl})
A C statement (sans semicolon) to mark @var{decl} to be emitted as a
public symbol such that extra copies in multiple translation units will
be discarded by the linker. Define this macro if your object file
format provides support for this concept, such as the @samp{COMDAT}
section flags in the Microsoft Windows PE/COFF format, and this support
requires changes to @var{decl}, such as putting it in a separate section.
+@end defmac
-@findex SUPPORTS_ONE_ONLY
-@item SUPPORTS_ONE_ONLY
+@defmac SUPPORTS_ONE_ONLY
A C expression which evaluates to true if the target supports one-only
semantics.
you want to control one-only symbol support with a compiler flag, or if
setting the @code{DECL_ONE_ONLY} flag is enough to mark a declaration to
be emitted as one-only.
+@end defmac
+
+@deftypefn {Target Hook} void TARGET_ASM_ASSEMBLE_VISIBILITY (tree @var{decl}, const char *@var{visibility})
+This target hook is a function to output to @var{asm_out_file} some
+commands that will make the symbol(s) associated with @var{decl} have
+hidden, protected or internal visibility as specified by @var{visibility}.
+@end deftypefn
-@findex ASM_OUTPUT_EXTERNAL
-@item ASM_OUTPUT_EXTERNAL (@var{stream}, @var{decl}, @var{name})
+@defmac TARGET_WEAK_NOT_IN_ARCHIVE_TOC
+A C expression that evaluates to true if the target's linker expects
+that weak symbols do not appear in a static archive's table of contents.
+The default is @code{0}.
+
+Leaving weak symbols out of an archive's table of contents means that,
+if a symbol will only have a definition in one translation unit and
+will have undefined references from other translation units, that
+symbol should not be weak. Defining this macro to be nonzero will
+thus have the effect that certain symbols that would normally be weak
+(explicit template instantiations, and vtables for polymorphic classes
+with noninline key methods) will instead be nonweak.
+
+The C++ ABI requires this macro to be zero. Define this macro for
+targets where full C++ ABI compliance is impossible and where linker
+restrictions require weak symbols to be left out of a static archive's
+table of contents.
+@end defmac
+
+@defmac ASM_OUTPUT_EXTERNAL (@var{stream}, @var{decl}, @var{name})
A C statement (sans semicolon) to output to the stdio stream
@var{stream} any text necessary for declaring the name of an external
symbol named @var{name} which is referenced in this compilation but
This macro need not be defined if it does not need to output anything.
The GNU assembler and most Unix assemblers don't require anything.
+@end defmac
-@findex ASM_OUTPUT_EXTERNAL_LIBCALL
-@item ASM_OUTPUT_EXTERNAL_LIBCALL (@var{stream}, @var{symref})
-A C statement (sans semicolon) to output on @var{stream} an assembler
+@deftypefn {Target Hook} void TARGET_ASM_EXTERNAL_LIBCALL (rtx @var{symref})
+This target hook is a function to output to @var{asm_out_file} an assembler
pseudo-op to declare a library function name external. The name of the
-library function is given by @var{symref}, which has type @code{rtx} and
-is a @code{symbol_ref}.
+library function is given by @var{symref}, which is a @code{symbol_ref}.
+@end deftypefn
-This macro need not be defined if it does not need to output anything.
-The GNU assembler and most Unix assemblers don't require anything.
+@deftypefn {Target Hook} void TARGET_ASM_MARK_DECL_PRESERVED (tree @var{decl})
+This target hook is a function to output to @var{asm_out_file} an assembler
+directive to annotate used symbol. Darwin target use .no_dead_code_strip
+directive.
+@end deftypefn
-@findex ASM_OUTPUT_LABELREF
-@item ASM_OUTPUT_LABELREF (@var{stream}, @var{name})
+@defmac ASM_OUTPUT_LABELREF (@var{stream}, @var{name})
A C statement (sans semicolon) to output to the stdio stream
@var{stream} a reference in assembler syntax to a label named
@var{name}. This should add @samp{_} to the front of the name, if that
is customary on your operating system, as it is in most Berkeley Unix
systems. This macro is used in @code{assemble_name}.
+@end defmac
-@findex ASM_OUTPUT_SYMBOL_REF
-@item ASM_OUTPUT_SYMBOL_REF (@var{stream}, @var{sym})
+@defmac ASM_OUTPUT_SYMBOL_REF (@var{stream}, @var{sym})
A C statement (sans semicolon) to output a reference to
@code{SYMBOL_REF} @var{sym}. If not defined, @code{assemble_name}
will be used to output the name of the symbol. This macro may be used
to modify the way a symbol is referenced depending on information
-encoded by @code{ENCODE_SECTION_INFO}.
+encoded by @code{TARGET_ENCODE_SECTION_INFO}.
+@end defmac
-@findex ASM_OUTPUT_LABEL_REF
-@item ASM_OUTPUT_LABEL_REF (@var{stream}, @var{buf})
+@defmac ASM_OUTPUT_LABEL_REF (@var{stream}, @var{buf})
A C statement (sans semicolon) to output a reference to @var{buf}, the
-result of ASM_GENERATE_INTERNAL_LABEL. If not defined,
+result of @code{ASM_GENERATE_INTERNAL_LABEL}. If not defined,
@code{assemble_name} will be used to output the name of the symbol.
This macro is not used by @code{output_asm_label}, or the @code{%l}
specifier that calls it; the intention is that this macro should be set
-when it is necessary to output a label differently when its address
-is being taken.
+when it is necessary to output a label differently when its address is
+being taken.
+@end defmac
-@findex ASM_OUTPUT_INTERNAL_LABEL
-@item ASM_OUTPUT_INTERNAL_LABEL (@var{stream}, @var{prefix}, @var{num})
-A C statement to output to the stdio stream @var{stream} a label whose
-name is made from the string @var{prefix} and the number @var{num}.
+@deftypefn {Target Hook} void TARGET_ASM_INTERNAL_LABEL (FILE *@var{stream}, const char *@var{prefix}, unsigned long @var{labelno})
+A function to output to the stdio stream @var{stream} a label whose
+name is made from the string @var{prefix} and the number @var{labelno}.
It is absolutely essential that these labels be distinct from the labels
used for user-level functions and variables. Otherwise, certain programs
beginning of a label has this effect. You should find out what
convention your system uses, and follow it.
-The usual definition of this macro is as follows:
-
-@example
-fprintf (@var{stream}, "L%s%d:\n", @var{prefix}, @var{num})
-@end example
+The default version of this function utilizes @code{ASM_GENERATE_INTERNAL_LABEL}.
+@end deftypefn
-@findex ASM_OUTPUT_DEBUG_LABEL
-@item ASM_OUTPUT_DEBUG_LABEL (@var{stream}, @var{prefix}, @var{num})
+@defmac ASM_OUTPUT_DEBUG_LABEL (@var{stream}, @var{prefix}, @var{num})
A C statement to output to the stdio stream @var{stream} a debug info
label whose name is made from the string @var{prefix} and the number
@var{num}. This is useful for VLIW targets, where debug info labels
bundles, but debug info labels can occur in the middle of instruction
bundles.
-If this macro is not defined, then @code{ASM_OUTPUT_INTERNAL_LABEL} will be
+If this macro is not defined, then @code{(*targetm.asm_out.internal_label)} will be
used.
+@end defmac
-@findex ASM_OUTPUT_ALTERNATE_LABEL_NAME
-@item ASM_OUTPUT_ALTERNATE_LABEL_NAME (@var{stream}, @var{string})
-A C statement to output to the stdio stream @var{stream} the string
-@var{string}.
-
-The default definition of this macro is as follows:
-
-@example
-fprintf (@var{stream}, "%s:\n", LABEL_ALTERNATE_NAME (INSN))
-@end example
-
-@findex ASM_GENERATE_INTERNAL_LABEL
-@item ASM_GENERATE_INTERNAL_LABEL (@var{string}, @var{prefix}, @var{num})
+@defmac ASM_GENERATE_INTERNAL_LABEL (@var{string}, @var{prefix}, @var{num})
A C statement to store into the string @var{string} a label whose name
is made from the string @var{prefix} and the number @var{num}.
This string, when output subsequently by @code{assemble_name}, should
-produce the output that @code{ASM_OUTPUT_INTERNAL_LABEL} would produce
+produce the output that @code{(*targetm.asm_out.internal_label)} would produce
with the same @var{prefix} and @var{num}.
If the string begins with @samp{*}, then @code{assemble_name} will
to output the string, and may change it. (Of course,
@code{ASM_OUTPUT_LABELREF} is also part of your machine description, so
you should know what it does on your machine.)
+@end defmac
-@findex ASM_FORMAT_PRIVATE_NAME
-@item ASM_FORMAT_PRIVATE_NAME (@var{outvar}, @var{name}, @var{number})
+@defmac ASM_FORMAT_PRIVATE_NAME (@var{outvar}, @var{name}, @var{number})
A C expression to assign to @var{outvar} (which is a variable of type
@code{char *}) a newly allocated string made from the string
@var{name} and the number @var{number}, with some suitable punctuation
or percent signs in assembler symbols; putting at least one of these
between the name and the number will suffice.
-@findex ASM_OUTPUT_DEF
-@item ASM_OUTPUT_DEF (@var{stream}, @var{name}, @var{value})
+If this macro is not defined, a default definition will be provided
+which is correct for most systems.
+@end defmac
+
+@defmac ASM_OUTPUT_DEF (@var{stream}, @var{name}, @var{value})
A C statement to output to the stdio stream @var{stream} assembler code
which defines (equates) the symbol @var{name} to have the value @var{value}.
@findex SET_ASM_OP
If @code{SET_ASM_OP} is defined, a default definition is provided which is
correct for most systems.
+@end defmac
-@findex ASM_OUTPUT_DEF_FROM_DECLS
-@item ASM_OUTPUT_DEF_FROM_DECLS (@var{stream}, @var{decl_of_name}, @var{decl_of_value})
+@defmac ASM_OUTPUT_DEF_FROM_DECLS (@var{stream}, @var{decl_of_name}, @var{decl_of_value})
A C statement to output to the stdio stream @var{stream} assembler code
which defines (equates) the symbol whose tree node is @var{decl_of_name}
to have the value of the tree node @var{decl_of_value}. This macro will
be used in preference to @samp{ASM_OUTPUT_DEF} if it is defined and if
the tree nodes are available.
-@findex ASM_OUTPUT_DEFINE_LABEL_DIFFERENCE_SYMBOL
-@item ASM_OUTPUT_DEFINE_LABEL_DIFFERENCE_SYMBOL (@var{stream}, @var{symbol}, @var{high}, @var{low})
-A C statement to output to the stdio stream @var{stream} assembler code
-which defines (equates) the symbol @var{symbol} to have a value equal to
-the difference of the two symbols @var{high} and @var{low},
-i.e.@: @var{high} minus @var{low}. GCC guarantees that the symbols @var{high}
-and @var{low} are already known by the assembler so that the difference
-resolves into a constant.
-
@findex SET_ASM_OP
If @code{SET_ASM_OP} is defined, a default definition is provided which is
correct for most systems.
-
-@findex ASM_OUTPUT_WEAK_ALIAS
-@item ASM_OUTPUT_WEAK_ALIAS (@var{stream}, @var{name}, @var{value})
+@end defmac
+
+@defmac TARGET_DEFERRED_OUTPUT_DEFS (@var{decl_of_name}, @var{decl_of_value})
+A C statement that evaluates to true if the assembler code which defines
+(equates) the symbol whose tree node is @var{decl_of_name} to have the value
+of the tree node @var{decl_of_value} should be emitted near the end of the
+current compilation unit. The default is to not defer output of defines.
+This macro affects defines output by @samp{ASM_OUTPUT_DEF} and
+@samp{ASM_OUTPUT_DEF_FROM_DECLS}.
+@end defmac
+
+@defmac ASM_OUTPUT_WEAK_ALIAS (@var{stream}, @var{name}, @var{value})
A C statement to output to the stdio stream @var{stream} assembler code
which defines (equates) the weak symbol @var{name} to have the value
@var{value}. If @var{value} is @code{NULL}, it defines @var{name} as
Define this macro if the target only supports weak aliases; define
@code{ASM_OUTPUT_DEF} instead if possible.
+@end defmac
-@findex OBJC_GEN_METHOD_LABEL
-@item OBJC_GEN_METHOD_LABEL (@var{buf}, @var{is_inst}, @var{class_name}, @var{cat_name}, @var{sel_name})
+@defmac OBJC_GEN_METHOD_LABEL (@var{buf}, @var{is_inst}, @var{class_name}, @var{cat_name}, @var{sel_name})
Define this macro to override the default assembler names used for
Objective-C methods.
On systems where the assembler can handle quoted names, you can use this
macro to provide more human-readable names.
+@end defmac
-@findex ASM_DECLARE_CLASS_REFERENCE
-@item ASM_DECLARE_CLASS_REFERENCE (@var{stream}, @var{name})
+@defmac ASM_DECLARE_CLASS_REFERENCE (@var{stream}, @var{name})
A C statement (sans semicolon) to output to the stdio stream
@var{stream} commands to declare that the label @var{name} is an
Objective-C class reference. This is only needed for targets whose
linkers have special support for NeXT-style runtimes.
+@end defmac
-@findex ASM_DECLARE_UNRESOLVED_REFERENCE
-@item ASM_DECLARE_UNRESOLVED_REFERENCE (@var{stream}, @var{name})
+@defmac ASM_DECLARE_UNRESOLVED_REFERENCE (@var{stream}, @var{name})
A C statement (sans semicolon) to output to the stdio stream
@var{stream} commands to declare that the label @var{name} is an
unresolved Objective-C class reference. This is only needed for targets
whose linkers have special support for NeXT-style runtimes.
-@end table
+@end defmac
@node Initialization
@subsection How Initialization Functions Are Handled
upon how the code in @file{crtstuff.c} is called. On systems that
support a @dfn{.init} section which is executed at program startup,
parts of @file{crtstuff.c} are compiled into that section. The
-program is linked by the @code{gcc} driver like this:
+program is linked by the @command{gcc} driver like this:
-@example
+@smallexample
ld -o @var{output_file} crti.o crtbegin.o @dots{} -lgcc crtend.o crtn.o
-@end example
+@end smallexample
The prologue of a function (@code{__init}) appears in the @code{.init}
section of @file{crti.o}; the epilogue appears in @file{crtn.o}. Likewise
Here are the macros that control how the compiler handles initialization
and termination functions:
-@table @code
-@findex INIT_SECTION_ASM_OP
-@item INIT_SECTION_ASM_OP
+@defmac INIT_SECTION_ASM_OP
If defined, a C string constant, including spacing, for the assembler
operation to identify the following data as initialization code. If not
defined, GCC will assume such a section does not exist. When you are
using special sections for initialization and termination functions, this
macro also controls how @file{crtstuff.c} and @file{libgcc2.c} arrange to
run the initialization functions.
+@end defmac
-@item HAS_INIT_SECTION
-@findex HAS_INIT_SECTION
+@defmac HAS_INIT_SECTION
If defined, @code{main} will not call @code{__main} as described above.
This macro should be defined for systems that control start-up code
on a symbol-by-symbol basis, such as OSF/1, and should not
be defined explicitly for systems that support @code{INIT_SECTION_ASM_OP}.
+@end defmac
-@item LD_INIT_SWITCH
-@findex LD_INIT_SWITCH
+@defmac LD_INIT_SWITCH
If defined, a C string constant for a switch that tells the linker that
the following symbol is an initialization routine.
+@end defmac
-@item LD_FINI_SWITCH
-@findex LD_FINI_SWITCH
+@defmac LD_FINI_SWITCH
If defined, a C string constant for a switch that tells the linker that
the following symbol is a finalization routine.
+@end defmac
-@item COLLECT_SHARED_INIT_FUNC (@var{stream}, @var{func})
+@defmac COLLECT_SHARED_INIT_FUNC (@var{stream}, @var{func})
If defined, a C statement that will write a function that can be
automatically called when a shared library is loaded. The function
should call @var{func}, which takes no arguments. If not defined, and
This function and the following one are used by collect2 when linking a
shared library that needs constructors or destructors, or has DWARF2
exception tables embedded in the code.
+@end defmac
-@item COLLECT_SHARED_FINI_FUNC (@var{stream}, @var{func})
+@defmac COLLECT_SHARED_FINI_FUNC (@var{stream}, @var{func})
If defined, a C statement that will write a function that can be
automatically called when a shared library is unloaded. The function
should call @var{func}, which takes no arguments. If not defined, and
the object format requires an explicit finalization function, then a
function called @code{_GLOBAL__DD} will be generated.
+@end defmac
-@item INVOKE__main
-@findex INVOKE__main
+@defmac INVOKE__main
If defined, @code{main} will call @code{__main} despite the presence of
@code{INIT_SECTION_ASM_OP}. This macro should be defined for systems
where the init section is not actually run automatically, but is still
useful for collecting the lists of constructors and destructors.
+@end defmac
-@item SUPPORTS_INIT_PRIORITY
-@findex SUPPORTS_INIT_PRIORITY
+@defmac SUPPORTS_INIT_PRIORITY
If nonzero, the C++ @code{init_priority} attribute is supported and the
compiler should emit instructions to control the order of initialization
of objects. If zero, the compiler will issue an error message upon
encountering an @code{init_priority} attribute.
-@end table
+@end defmac
@deftypefn {Target Hook} bool TARGET_HAVE_CTORS_DTORS
This value is true if the target supports some ``native'' method of
constructors, then that program normally uses @command{nm} to scan
an object file for constructor functions to be called.
-On certain kinds of systems, you can define these macros to make
+On certain kinds of systems, you can define this macro to make
@command{collect2} work faster (and, in some cases, make it work at all):
-@table @code
-@findex OBJECT_FORMAT_COFF
-@item OBJECT_FORMAT_COFF
+@defmac OBJECT_FORMAT_COFF
Define this macro if the system uses COFF (Common Object File Format)
object files, so that @command{collect2} can assume this format and scan
object files directly for dynamic constructor/destructor functions.
-@findex OBJECT_FORMAT_ROSE
-@item OBJECT_FORMAT_ROSE
-Define this macro if the system uses ROSE format object files, so that
-@command{collect2} can assume this format and scan object files directly
-for dynamic constructor/destructor functions.
-
-These macros are effective only in a native compiler; @command{collect2} as
+This macro is effective only in a native compiler; @command{collect2} as
part of a cross compiler always uses @command{nm} for the target machine.
+@end defmac
-@findex REAL_NM_FILE_NAME
-@item REAL_NM_FILE_NAME
+@defmac REAL_NM_FILE_NAME
Define this macro as a C string constant containing the file name to use
to execute @command{nm}. The default is to search the path normally for
@command{nm}.
dynamic dependencies of a given library or executable, you can define
these macros to enable support for running initialization and
termination functions in shared libraries:
+@end defmac
-@findex LDD_SUFFIX
-@item LDD_SUFFIX
+@defmac LDD_SUFFIX
Define this macro to a C string constant containing the name of the program
which lists dynamic dependencies, like @command{"ldd"} under SunOS 4.
+@end defmac
-@findex PARSE_LDD_OUTPUT
-@item PARSE_LDD_OUTPUT (@var{ptr})
+@defmac PARSE_LDD_OUTPUT (@var{ptr})
Define this macro to be C code that extracts filenames from the output
of the program denoted by @code{LDD_SUFFIX}. @var{ptr} is a variable
of type @code{char *} that points to the beginning of a line of output
from @code{LDD_SUFFIX}. If the line lists a dynamic dependency, the
code must advance @var{ptr} to the beginning of the filename on that
line. Otherwise, it must set @var{ptr} to @code{NULL}.
-@end table
+@end defmac
+
+@defmac SHLIB_SUFFIX
+Define this macro to a C string constant containing the default shared
+library extension of the target (e.g., @samp{".so"}). @command{collect2}
+strips version information after this suffix when generating global
+constructor and destructor names. This define is only needed on targets
+that use @command{collect2} to process constructors and destructors.
+@end defmac
@node Instruction Output
@subsection Output of Assembler Instructions
@c prevent bad page break with this line
This describes assembler instruction output.
-@table @code
-@findex REGISTER_NAMES
-@item REGISTER_NAMES
+@defmac REGISTER_NAMES
A C initializer containing the assembler's names for the machine
registers, each one as a C string constant. This is what translates
register numbers in the compiler into assembler language.
+@end defmac
-@findex ADDITIONAL_REGISTER_NAMES
-@item ADDITIONAL_REGISTER_NAMES
+@defmac ADDITIONAL_REGISTER_NAMES
If defined, a C initializer for an array of structures containing a name
and a register number. This macro defines additional names for hard
registers, thus allowing the @code{asm} option in declarations to refer
to registers using alternate names.
+@end defmac
-@findex ASM_OUTPUT_OPCODE
-@item ASM_OUTPUT_OPCODE (@var{stream}, @var{ptr})
+@defmac ASM_OUTPUT_OPCODE (@var{stream}, @var{ptr})
Define this macro if you are using an unusual assembler that
requires different names for the machine instructions.
If the macro definition does nothing, the instruction is output
in the usual way.
+@end defmac
-@findex FINAL_PRESCAN_INSN
-@item FINAL_PRESCAN_INSN (@var{insn}, @var{opvec}, @var{noperands})
+@defmac FINAL_PRESCAN_INSN (@var{insn}, @var{opvec}, @var{noperands})
If defined, a C statement to be executed just prior to the output of
assembler code for @var{insn}, to modify the extracted operands so
they will be output differently.
writing conditional output routines in those patterns.
If this macro is not defined, it is equivalent to a null statement.
+@end defmac
-@findex FINAL_PRESCAN_LABEL
-@item FINAL_PRESCAN_LABEL
-If defined, @code{FINAL_PRESCAN_INSN} will be called on each
-@code{CODE_LABEL}. In that case, @var{opvec} will be a null pointer and
-@var{noperands} will be zero.
-
-@findex PRINT_OPERAND
-@item PRINT_OPERAND (@var{stream}, @var{x}, @var{code})
+@defmac PRINT_OPERAND (@var{stream}, @var{x}, @var{code})
A C compound statement to output to stdio stream @var{stream} the
assembler syntax for an instruction operand @var{x}. @var{x} is an
RTL expression.
(a @samp{%} followed by a punctuation character), this macro is called
with a null pointer for @var{x} and the punctuation character for
@var{code}.
+@end defmac
-@findex PRINT_OPERAND_PUNCT_VALID_P
-@item PRINT_OPERAND_PUNCT_VALID_P (@var{code})
+@defmac PRINT_OPERAND_PUNCT_VALID_P (@var{code})
A C expression which evaluates to true if @var{code} is a valid
punctuation character for use in the @code{PRINT_OPERAND} macro. If
@code{PRINT_OPERAND_PUNCT_VALID_P} is not defined, it means that no
punctuation characters (except for the standard one, @samp{%}) are used
in this way.
+@end defmac
-@findex PRINT_OPERAND_ADDRESS
-@item PRINT_OPERAND_ADDRESS (@var{stream}, @var{x})
+@defmac PRINT_OPERAND_ADDRESS (@var{stream}, @var{x})
A C compound statement to output to stdio stream @var{stream} the
assembler syntax for an instruction operand that is a memory reference
whose address is @var{x}. @var{x} is an RTL expression.
-@cindex @code{ENCODE_SECTION_INFO} usage
+@cindex @code{TARGET_ENCODE_SECTION_INFO} usage
On some machines, the syntax for a symbolic address depends on the
-section that the address refers to. On these machines, define the macro
-@code{ENCODE_SECTION_INFO} to store the information into the
-@code{symbol_ref}, and then check for it here. @xref{Assembler Format}.
+section that the address refers to. On these machines, define the hook
+@code{TARGET_ENCODE_SECTION_INFO} to store the information into the
+@code{symbol_ref}, and then check for it here. @xref{Assembler
+Format}.
+@end defmac
-@findex DBR_OUTPUT_SEQEND
@findex dbr_sequence_length
-@item DBR_OUTPUT_SEQEND(@var{file})
+@defmac DBR_OUTPUT_SEQEND (@var{file})
A C statement, to be executed after all slot-filler instructions have
been output. If necessary, call @code{dbr_sequence_length} to
determine the number of slots filled in a sequence (zero if not
Don't define this macro if it has nothing to do, but it is helpful in
reading assembly output if the extent of the delay sequence is made
explicit (e.g.@: with white space).
+@end defmac
@findex final_sequence
Note that output routines for instructions with delay slots must be
processing a sequence, otherwise it contains the @code{sequence} rtx
being output.
-@findex REGISTER_PREFIX
-@findex LOCAL_LABEL_PREFIX
-@findex USER_LABEL_PREFIX
-@findex IMMEDIATE_PREFIX
@findex asm_fprintf
-@item REGISTER_PREFIX
-@itemx LOCAL_LABEL_PREFIX
-@itemx USER_LABEL_PREFIX
-@itemx IMMEDIATE_PREFIX
+@defmac REGISTER_PREFIX
+@defmacx LOCAL_LABEL_PREFIX
+@defmacx USER_LABEL_PREFIX
+@defmacx IMMEDIATE_PREFIX
If defined, C string expressions to be used for the @samp{%R}, @samp{%L},
@samp{%U}, and @samp{%I} options of @code{asm_fprintf} (see
@file{final.c}). These are useful when a single @file{md} file must
support multiple assembler formats. In that case, the various @file{tm.h}
files can define these macros differently.
+@end defmac
-@item ASM_FPRINTF_EXTENSIONS(@var{file}, @var{argptr}, @var{format})
-@findex ASM_FPRINTF_EXTENSIONS
+@defmac ASM_FPRINTF_EXTENSIONS (@var{file}, @var{argptr}, @var{format})
If defined this macro should expand to a series of @code{case}
statements which will be parsed inside the @code{switch} statement of
the @code{asm_fprintf} function. This allows targets to define extra
printf formats which may useful when generating their assembler
-statements. Note that upper case letters are reserved for future
+statements. Note that uppercase letters are reserved for future
generic extensions to asm_fprintf, and so are not available to target
specific code. The output file is given by the parameter @var{file}.
The varargs input pointer is @var{argptr} and the rest of the format
string, starting the character after the one that is being switched
upon, is pointed to by @var{format}.
+@end defmac
-@findex ASSEMBLER_DIALECT
-@item ASSEMBLER_DIALECT
+@defmac ASSEMBLER_DIALECT
If your target supports multiple dialects of assembler language (such as
different opcodes), define this macro as a C expression that gives the
numeric index of the assembler language dialect to use, with zero as the
@code{ASSEMBLER_DIALECT} and use the @samp{@{option0|option1@}} syntax
if the syntax variant are larger and involve such things as different
opcodes or operand order.
+@end defmac
-@findex ASM_OUTPUT_REG_PUSH
-@item ASM_OUTPUT_REG_PUSH (@var{stream}, @var{regno})
+@defmac ASM_OUTPUT_REG_PUSH (@var{stream}, @var{regno})
A C expression to output to @var{stream} some assembler code
which will push hard register number @var{regno} onto the stack.
The code need not be optimal, since this macro is used only when
profiling.
+@end defmac
-@findex ASM_OUTPUT_REG_POP
-@item ASM_OUTPUT_REG_POP (@var{stream}, @var{regno})
+@defmac ASM_OUTPUT_REG_POP (@var{stream}, @var{regno})
A C expression to output to @var{stream} some assembler code
which will pop hard register number @var{regno} off of the stack.
The code need not be optimal, since this macro is used only when
profiling.
-@end table
+@end defmac
@node Dispatch Tables
@subsection Output of Dispatch Tables
@c prevent bad page break with this line
This concerns dispatch tables.
-@table @code
@cindex dispatch table
-@findex ASM_OUTPUT_ADDR_DIFF_ELT
-@item ASM_OUTPUT_ADDR_DIFF_ELT (@var{stream}, @var{body}, @var{value}, @var{rel})
+@defmac ASM_OUTPUT_ADDR_DIFF_ELT (@var{stream}, @var{body}, @var{value}, @var{rel})
A C statement to output to the stdio stream @var{stream} an assembler
pseudo-instruction to generate a difference between two labels.
@var{value} and @var{rel} are the numbers of two internal labels. The
definitions of these labels are output using
-@code{ASM_OUTPUT_INTERNAL_LABEL}, and they must be printed in the same
+@code{(*targetm.asm_out.internal_label)}, and they must be printed in the same
way here. For example,
-@example
+@smallexample
fprintf (@var{stream}, "\t.word L%d-L%d\n",
@var{value}, @var{rel})
-@end example
+@end smallexample
You must provide this macro on machines where the addresses in a
dispatch table are relative to the table's own address. If defined, GCC
will also use this macro on all machines when producing PIC@.
@var{body} is the body of the @code{ADDR_DIFF_VEC}; it is provided so that the
mode and flags can be read.
+@end defmac
-@findex ASM_OUTPUT_ADDR_VEC_ELT
-@item ASM_OUTPUT_ADDR_VEC_ELT (@var{stream}, @var{value})
+@defmac ASM_OUTPUT_ADDR_VEC_ELT (@var{stream}, @var{value})
This macro should be provided on machines where the addresses
in a dispatch table are absolute.
The definition should be a C statement to output to the stdio stream
@var{stream} an assembler pseudo-instruction to generate a reference to
a label. @var{value} is the number of an internal label whose
-definition is output using @code{ASM_OUTPUT_INTERNAL_LABEL}.
+definition is output using @code{(*targetm.asm_out.internal_label)}.
For example,
-@example
+@smallexample
fprintf (@var{stream}, "\t.word L%d\n", @var{value})
-@end example
+@end smallexample
+@end defmac
-@findex ASM_OUTPUT_CASE_LABEL
-@item ASM_OUTPUT_CASE_LABEL (@var{stream}, @var{prefix}, @var{num}, @var{table})
+@defmac ASM_OUTPUT_CASE_LABEL (@var{stream}, @var{prefix}, @var{num}, @var{table})
Define this if the label before a jump-table needs to be output
specially. The first three arguments are the same as for
-@code{ASM_OUTPUT_INTERNAL_LABEL}; the fourth argument is the
+@code{(*targetm.asm_out.internal_label)}; the fourth argument is the
jump-table which follows (a @code{jump_insn} containing an
@code{addr_vec} or @code{addr_diff_vec}).
for the table.
If this macro is not defined, these labels are output with
-@code{ASM_OUTPUT_INTERNAL_LABEL}.
+@code{(*targetm.asm_out.internal_label)}.
+@end defmac
-@findex ASM_OUTPUT_CASE_END
-@item ASM_OUTPUT_CASE_END (@var{stream}, @var{num}, @var{table})
+@defmac ASM_OUTPUT_CASE_END (@var{stream}, @var{num}, @var{table})
Define this if something special must be output at the end of a
jump-table. The definition should be a C statement to be executed
after the assembler code for the table is written. It should write
If this macro is not defined, nothing special is output at the end of
the jump-table.
-@end table
+@end defmac
+
+@deftypefn {Target Hook} void TARGET_ASM_EMIT_UNWIND_LABEL (@var{stream}, @var{decl}, @var{for_eh}, @var{empty})
+This target hook emits a label at the beginning of each FDE@. It
+should be defined on targets where FDEs need special labels, and it
+should write the appropriate label, for the FDE associated with the
+function declaration @var{decl}, to the stdio stream @var{stream}.
+The third argument, @var{for_eh}, is a boolean: true if this is for an
+exception table. The fourth argument, @var{empty}, is a boolean:
+true if this is a placeholder label for an omitted FDE@.
+
+The default is that FDEs are not given nonlocal labels.
+@end deftypefn
+
+@deftypefn {Target Hook} void TARGET_ASM_EMIT_EXCEPT_TABLE_LABEL (@var{stream})
+This target hook emits a label at the beginning of the exception table.
+It should be defined on targets where it is desirable for the table
+to be broken up according to function.
+
+The default is that no label is emitted.
+@end deftypefn
+
+@deftypefn {Target Hook} void TARGET_UNWIND_EMIT (FILE * @var{stream}, rtx @var{insn})
+This target hook emits and assembly directives required to unwind the
+given instruction. This is only used when TARGET_UNWIND_INFO is set.
+@end deftypefn
@node Exception Region Output
@subsection Assembler Commands for Exception Regions
This describes commands marking the start and the end of an exception
region.
-@table @code
-@findex EH_FRAME_SECTION_NAME
-@item EH_FRAME_SECTION_NAME
+@defmac EH_FRAME_SECTION_NAME
If defined, a C string constant for the name of the section containing
exception handling frame unwind information. If not defined, GCC will
provide a default definition if the target supports named sections.
You should define this symbol if your target supports DWARF 2 frame
unwind information and the default definition does not work.
+@end defmac
-@findex EH_FRAME_IN_DATA_SECTION
-@item EH_FRAME_IN_DATA_SECTION
+@defmac EH_FRAME_IN_DATA_SECTION
If defined, DWARF 2 frame unwind information will be placed in the
data section even though the target supports named sections. This
might be necessary, for instance, if the system linker does garbage
Do not define this macro unless @code{TARGET_ASM_NAMED_SECTION} is
also defined.
+@end defmac
+
+@defmac EH_TABLES_CAN_BE_READ_ONLY
+Define this macro to 1 if your target is such that no frame unwind
+information encoding used with non-PIC code will ever require a
+runtime relocation, but the linker may not support merging read-only
+and read-write sections into a single read-write section.
+@end defmac
-@findex MASK_RETURN_ADDR
-@item MASK_RETURN_ADDR
+@defmac MASK_RETURN_ADDR
An rtx used to mask the return address found via @code{RETURN_ADDR_RTX}, so
that it does not contain any extraneous set bits in it.
+@end defmac
-@findex DWARF2_UNWIND_INFO
-@item DWARF2_UNWIND_INFO
+@defmac DWARF2_UNWIND_INFO
Define this macro to 0 if your target supports DWARF 2 frame unwind
information, but it does not yet work with exception handling.
Otherwise, if your target supports this information (if it defines
@samp{INCOMING_RETURN_ADDR_RTX} and either @samp{UNALIGNED_INT_ASM_OP}
-or @samp{OBJECT_FORMAT_ELF}), GCC will provide a default definition of
-1.
+or @samp{OBJECT_FORMAT_ELF}), GCC will provide a default definition of 1.
+
+If @code{TARGET_UNWIND_INFO} is defined, the target specific unwinder
+will be used in all cases. Defining this macro will enable the generation
+of DWARF 2 frame debugging information.
-If this macro is defined to 1, the DWARF 2 unwinder will be the default
-exception handling mechanism; otherwise, @code{setjmp}/@code{longjmp} will be used by
+If @code{TARGET_UNWIND_INFO} is not defined, and this macro is defined to 1,
+the DWARF 2 unwinder will be the default exception handling mechanism;
+otherwise, the @code{setjmp}/@code{longjmp}-based scheme will be used by
default.
+@end defmac
-If this macro is defined to anything, the DWARF 2 unwinder will be used
-instead of inline unwinders and @code{__unwind_function} in the non-@code{setjmp} case.
+@defmac TARGET_UNWIND_INFO
+Define this macro if your target has ABI specified unwind tables. Usually
+these will be output by @code{TARGET_UNWIND_EMIT}.
+@end defmac
-@findex DWARF_CIE_DATA_ALIGNMENT
-@item DWARF_CIE_DATA_ALIGNMENT
+@deftypevar {Target Hook} bool TARGET_UNWIND_TABLES_DEFAULT
+This variable should be set to @code{true} if the target ABI requires unwinding
+tables even when exceptions are not used.
+@end deftypevar
+
+@defmac MUST_USE_SJLJ_EXCEPTIONS
+This macro need only be defined if @code{DWARF2_UNWIND_INFO} is
+runtime-variable. In that case, @file{except.h} cannot correctly
+determine the corresponding definition of @code{MUST_USE_SJLJ_EXCEPTIONS},
+so the target must provide it directly.
+@end defmac
+
+@defmac DONT_USE_BUILTIN_SETJMP
+Define this macro to 1 if the @code{setjmp}/@code{longjmp}-based scheme
+should use the @code{setjmp}/@code{longjmp} functions from the C library
+instead of the @code{__builtin_setjmp}/@code{__builtin_longjmp} machinery.
+@end defmac
+
+@defmac DWARF_CIE_DATA_ALIGNMENT
This macro need only be defined if the target might save registers in the
function prologue at an offset to the stack pointer that is not aligned to
@code{UNITS_PER_WORD}. The definition should be the negative minimum
alignment if @code{STACK_GROWS_DOWNWARD} is defined, and the positive
minimum alignment otherwise. @xref{SDB and DWARF}. Only applicable if
the target supports DWARF 2 frame unwind information.
+@end defmac
-@end table
+@deftypevar {Target Hook} bool TARGET_TERMINATE_DW2_EH_FRAME_INFO
+Contains the value true if the target should add a zero word onto the
+end of a Dwarf-2 frame info section when used for exception handling.
+Default value is false if @code{EH_FRAME_SECTION_NAME} is defined, and
+true otherwise.
+@end deftypevar
+
+@deftypefn {Target Hook} rtx TARGET_DWARF_REGISTER_SPAN (rtx @var{reg})
+Given a register, this hook should return a parallel of registers to
+represent where to find the register pieces. Define this hook if the
+register and its mode are represented in Dwarf in non-contiguous
+locations, or if the register should be represented in more than one
+register in Dwarf. Otherwise, this hook should return @code{NULL_RTX}.
+If not defined, the default is to return @code{NULL_RTX}.
+@end deftypefn
+
+@deftypefn {Target Hook} void TARGET_INIT_DWARF_REG_SIZES_EXTRA (tree @var{address})
+If some registers are represented in Dwarf-2 unwind information in
+multiple pieces, define this hook to fill in information about the
+sizes of those pieces in the table used by the unwinder at runtime.
+It will be called by @code{expand_builtin_init_dwarf_reg_sizes} after
+filling in a single size corresponding to each hard register;
+@var{address} is the address of the table.
+@end deftypefn
-@deftypefn {Target Hook} void TARGET_ASM_EXCEPTION_SECTION ()
-If defined, a function that switches to the section in which the main
-exception table is to be placed (@pxref{Sections}). The default is a
-function that switches to a section named @code{.gcc_except_table} on
-machines that support named sections via
-@code{TARGET_ASM_NAMED_SECTION}, otherwise if @option{-fpic} or
-@option{-fPIC} is in effect, the @code{data_section}, otherwise the
-@code{readonly_data_section}.
+@deftypefn {Target Hook} bool TARGET_ASM_TTYPE (rtx @var{sym})
+This hook is used to output a reference from a frame unwinding table to
+the type_info object identified by @var{sym}. It should return @code{true}
+if the reference was output. Returning @code{false} will cause the
+reference to be output using the normal Dwarf2 routines.
@end deftypefn
-@deftypefn {Target Hook} void TARGET_ASM_EH_FRAME_SECTION ()
-If defined, a function that switches to the section in which the DWARF 2
-frame unwind information to be placed (@pxref{Sections}). The default
-is a function that outputs a standard GAS section directive, if
-@code{EH_FRAME_SECTION_NAME} is defined, or else a data section
-directive followed by a synthetic label.
+@deftypefn {Target Hook} bool TARGET_ARM_EABI_UNWINDER
+This hook should be set to @code{true} on targets that use an ARM EABI
+based unwinding library, and @code{false} on other targets. This effects
+the format of unwinding tables, and how the unwinder in entered after
+running a cleanup. The default is @code{false}.
@end deftypefn
@node Alignment Output
@c prevent bad page break with this line
This describes commands for alignment.
-@table @code
-@findex JUMP_ALIGN
-@item JUMP_ALIGN (@var{label})
+@defmac JUMP_ALIGN (@var{label})
The alignment (log base 2) to put in front of @var{label}, which is
a common destination of jumps and has no fallthru incoming edge.
to set the variable @var{align_jumps} in the target's
@code{OVERRIDE_OPTIONS}. Otherwise, you should try to honor the user's
selection in @var{align_jumps} in a @code{JUMP_ALIGN} implementation.
+@end defmac
-@findex LABEL_ALIGN_AFTER_BARRIER
-@item LABEL_ALIGN_AFTER_BARRIER (@var{label})
+@defmac LABEL_ALIGN_AFTER_BARRIER (@var{label})
The alignment (log base 2) to put in front of @var{label}, which follows
a @code{BARRIER}.
This macro need not be defined if you don't want any special alignment
to be done at such a time. Most machine descriptions do not currently
define the macro.
+@end defmac
-@findex LABEL_ALIGN_AFTER_BARRIER_MAX_SKIP
-@item LABEL_ALIGN_AFTER_BARRIER_MAX_SKIP
+@defmac LABEL_ALIGN_AFTER_BARRIER_MAX_SKIP
The maximum number of bytes to skip when applying
@code{LABEL_ALIGN_AFTER_BARRIER}. This works only if
@code{ASM_OUTPUT_MAX_SKIP_ALIGN} is defined.
+@end defmac
-@findex LOOP_ALIGN
-@item LOOP_ALIGN (@var{label})
+@defmac LOOP_ALIGN (@var{label})
The alignment (log base 2) to put in front of @var{label}, which follows
a @code{NOTE_INSN_LOOP_BEG} note.
to set the variable @code{align_loops} in the target's
@code{OVERRIDE_OPTIONS}. Otherwise, you should try to honor the user's
selection in @code{align_loops} in a @code{LOOP_ALIGN} implementation.
+@end defmac
-@findex LOOP_ALIGN_MAX_SKIP
-@item LOOP_ALIGN_MAX_SKIP
+@defmac LOOP_ALIGN_MAX_SKIP
The maximum number of bytes to skip when applying @code{LOOP_ALIGN}.
This works only if @code{ASM_OUTPUT_MAX_SKIP_ALIGN} is defined.
+@end defmac
-@findex LABEL_ALIGN
-@item LABEL_ALIGN (@var{label})
+@defmac LABEL_ALIGN (@var{label})
The alignment (log base 2) to put in front of @var{label}.
If @code{LABEL_ALIGN_AFTER_BARRIER} / @code{LOOP_ALIGN} specify a different alignment,
the maximum of the specified values is used.
to set the variable @code{align_labels} in the target's
@code{OVERRIDE_OPTIONS}. Otherwise, you should try to honor the user's
selection in @code{align_labels} in a @code{LABEL_ALIGN} implementation.
+@end defmac
-@findex LABEL_ALIGN_MAX_SKIP
-@item LABEL_ALIGN_MAX_SKIP
+@defmac LABEL_ALIGN_MAX_SKIP
The maximum number of bytes to skip when applying @code{LABEL_ALIGN}.
This works only if @code{ASM_OUTPUT_MAX_SKIP_ALIGN} is defined.
+@end defmac
-@findex ASM_OUTPUT_SKIP
-@item ASM_OUTPUT_SKIP (@var{stream}, @var{nbytes})
+@defmac ASM_OUTPUT_SKIP (@var{stream}, @var{nbytes})
A C statement to output to the stdio stream @var{stream} an assembler
instruction to advance the location counter by @var{nbytes} bytes.
Those bytes should be zero when loaded. @var{nbytes} will be a C
-expression of type @code{int}.
+expression of type @code{unsigned HOST_WIDE_INT}.
+@end defmac
-@findex ASM_NO_SKIP_IN_TEXT
-@item ASM_NO_SKIP_IN_TEXT
+@defmac ASM_NO_SKIP_IN_TEXT
Define this macro if @code{ASM_OUTPUT_SKIP} should not be used in the
text section because it fails to put zeros in the bytes that are skipped.
This is true on many Unix systems, where the pseudo--op to skip bytes
produces no-op instructions rather than zeros when used in the text
section.
+@end defmac
-@findex ASM_OUTPUT_ALIGN
-@item ASM_OUTPUT_ALIGN (@var{stream}, @var{power})
+@defmac ASM_OUTPUT_ALIGN (@var{stream}, @var{power})
A C statement to output to the stdio stream @var{stream} an assembler
command to advance the location counter to a multiple of 2 to the
@var{power} bytes. @var{power} will be a C expression of type @code{int}.
+@end defmac
+
+@defmac ASM_OUTPUT_ALIGN_WITH_NOP (@var{stream}, @var{power})
+Like @code{ASM_OUTPUT_ALIGN}, except that the ``nop'' instruction is used
+for padding, if necessary.
+@end defmac
-@findex ASM_OUTPUT_MAX_SKIP_ALIGN
-@item ASM_OUTPUT_MAX_SKIP_ALIGN (@var{stream}, @var{power}, @var{max_skip})
+@defmac ASM_OUTPUT_MAX_SKIP_ALIGN (@var{stream}, @var{power}, @var{max_skip})
A C statement to output to the stdio stream @var{stream} an assembler
command to advance the location counter to a multiple of 2 to the
@var{power} bytes, but only if @var{max_skip} or fewer bytes are needed to
satisfy the alignment request. @var{power} and @var{max_skip} will be
a C expression of type @code{int}.
-@end table
+@end defmac
@need 3000
@node Debugging Info
@c prevent bad page break with this line
These macros affect all debugging formats.
-@table @code
-@findex DBX_REGISTER_NUMBER
-@item DBX_REGISTER_NUMBER (@var{regno})
+@defmac DBX_REGISTER_NUMBER (@var{regno})
A C expression that returns the DBX register number for the compiler
register number @var{regno}. In the default macro provided, the value
of this expression will be @var{regno} itself. But sometimes there are
If you find yourself defining @code{DBX_REGISTER_NUMBER} in way that
does not preserve register pairs, then what you must do instead is
redefine the actual register numbering scheme.
+@end defmac
-@findex DEBUGGER_AUTO_OFFSET
-@item DEBUGGER_AUTO_OFFSET (@var{x})
+@defmac DEBUGGER_AUTO_OFFSET (@var{x})
A C expression that returns the integer offset value for an automatic
variable having address @var{x} (an RTL expression). The default
computation assumes that @var{x} is based on the frame-pointer and
that produce debugging output for DBX or COFF-style debugging output
for SDB and allow the frame-pointer to be eliminated when the
@option{-g} options is used.
+@end defmac
-@findex DEBUGGER_ARG_OFFSET
-@item DEBUGGER_ARG_OFFSET (@var{offset}, @var{x})
+@defmac DEBUGGER_ARG_OFFSET (@var{offset}, @var{x})
A C expression that returns the integer offset value for an argument
having address @var{x} (an RTL expression). The nominal offset is
@var{offset}.
+@end defmac
-@findex PREFERRED_DEBUGGING_TYPE
-@item PREFERRED_DEBUGGING_TYPE
+@defmac PREFERRED_DEBUGGING_TYPE
A C expression that returns the type of debugging output GCC should
produce when the user specifies just @option{-g}. Define
this if you have arranged for GCC to support more than one format of
When the user specifies @option{-ggdb}, GCC normally also uses the
value of this macro to select the debugging output format, but with two
-exceptions. If @code{DWARF2_DEBUGGING_INFO} is defined and
-@code{LINKER_DOES_NOT_WORK_WITH_DWARF2} is not defined, GCC uses the
+exceptions. If @code{DWARF2_DEBUGGING_INFO} is defined, GCC uses the
value @code{DWARF2_DEBUG}. Otherwise, if @code{DBX_DEBUGGING_INFO} is
defined, GCC uses @code{DBX_DEBUG}.
The value of this macro only affects the default debugging output; the
user can always get a specific type of output by using @option{-gstabs},
-@option{-gcoff}, @option{-gdwarf-1}, @option{-gdwarf-2}, @option{-gxcoff},
-or @option{-gvms}.
-@end table
+@option{-gcoff}, @option{-gdwarf-2}, @option{-gxcoff}, or @option{-gvms}.
+@end defmac
@node DBX Options
@subsection Specific Options for DBX Output
@c prevent bad page break with this line
These are specific options for DBX output.
-@table @code
-@findex DBX_DEBUGGING_INFO
-@item DBX_DEBUGGING_INFO
+@defmac DBX_DEBUGGING_INFO
Define this macro if GCC should produce debugging output for DBX
in response to the @option{-g} option.
+@end defmac
-@findex XCOFF_DEBUGGING_INFO
-@item XCOFF_DEBUGGING_INFO
+@defmac XCOFF_DEBUGGING_INFO
Define this macro if GCC should produce XCOFF format debugging output
in response to the @option{-g} option. This is a variant of DBX format.
+@end defmac
-@findex DEFAULT_GDB_EXTENSIONS
-@item DEFAULT_GDB_EXTENSIONS
+@defmac DEFAULT_GDB_EXTENSIONS
Define this macro to control whether GCC should by default generate
GDB's extended version of DBX debugging information (assuming DBX-format
debugging information is enabled at all). If you don't define the
macro, the default is 1: always generate the extended information
if there is any occasion to.
+@end defmac
-@findex DEBUG_SYMS_TEXT
-@item DEBUG_SYMS_TEXT
+@defmac DEBUG_SYMS_TEXT
Define this macro if all @code{.stabs} commands should be output while
in the text section.
+@end defmac
-@findex ASM_STABS_OP
-@item ASM_STABS_OP
+@defmac ASM_STABS_OP
A C string constant, including spacing, naming the assembler pseudo op to
use instead of @code{"\t.stabs\t"} to define an ordinary debugging symbol.
If you don't define this macro, @code{"\t.stabs\t"} is used. This macro
applies only to DBX debugging information format.
+@end defmac
-@findex ASM_STABD_OP
-@item ASM_STABD_OP
+@defmac ASM_STABD_OP
A C string constant, including spacing, naming the assembler pseudo op to
use instead of @code{"\t.stabd\t"} to define a debugging symbol whose
value is the current location. If you don't define this macro,
@code{"\t.stabd\t"} is used. This macro applies only to DBX debugging
information format.
+@end defmac
-@findex ASM_STABN_OP
-@item ASM_STABN_OP
+@defmac ASM_STABN_OP
A C string constant, including spacing, naming the assembler pseudo op to
use instead of @code{"\t.stabn\t"} to define a debugging symbol with no
name. If you don't define this macro, @code{"\t.stabn\t"} is used. This
macro applies only to DBX debugging information format.
+@end defmac
-@findex DBX_NO_XREFS
-@item DBX_NO_XREFS
+@defmac DBX_NO_XREFS
Define this macro if DBX on your system does not support the construct
@samp{xs@var{tagname}}. On some systems, this construct is used to
describe a forward reference to a structure named @var{tagname}.
On other systems, this construct is not supported at all.
+@end defmac
-@findex DBX_CONTIN_LENGTH
-@item DBX_CONTIN_LENGTH
+@defmac DBX_CONTIN_LENGTH
A symbol name in DBX-format debugging information is normally
continued (split into two separate @code{.stabs} directives) when it
exceeds a certain length (by default, 80 characters). On some
must not be done. You can inhibit splitting by defining this macro
with the value zero. You can override the default splitting-length by
defining this macro as an expression for the length you desire.
+@end defmac
-@findex DBX_CONTIN_CHAR
-@item DBX_CONTIN_CHAR
+@defmac DBX_CONTIN_CHAR
Normally continuation is indicated by adding a @samp{\} character to
the end of a @code{.stabs} string when a continuation follows. To use
a different character instead, define this macro as a character
constant for the character you want to use. Do not define this macro
if backslash is correct for your system.
+@end defmac
-@findex DBX_STATIC_STAB_DATA_SECTION
-@item DBX_STATIC_STAB_DATA_SECTION
+@defmac DBX_STATIC_STAB_DATA_SECTION
Define this macro if it is necessary to go to the data section before
outputting the @samp{.stabs} pseudo-op for a non-global static
variable.
+@end defmac
-@findex DBX_TYPE_DECL_STABS_CODE
-@item DBX_TYPE_DECL_STABS_CODE
+@defmac DBX_TYPE_DECL_STABS_CODE
The value to use in the ``code'' field of the @code{.stabs} directive
for a typedef. The default is @code{N_LSYM}.
+@end defmac
-@findex DBX_STATIC_CONST_VAR_CODE
-@item DBX_STATIC_CONST_VAR_CODE
+@defmac DBX_STATIC_CONST_VAR_CODE
The value to use in the ``code'' field of the @code{.stabs} directive
for a static variable located in the text section. DBX format does not
provide any ``right'' way to do this. The default is @code{N_FUN}.
+@end defmac
-@findex DBX_REGPARM_STABS_CODE
-@item DBX_REGPARM_STABS_CODE
+@defmac DBX_REGPARM_STABS_CODE
The value to use in the ``code'' field of the @code{.stabs} directive
for a parameter passed in registers. DBX format does not provide any
``right'' way to do this. The default is @code{N_RSYM}.
+@end defmac
-@findex DBX_REGPARM_STABS_LETTER
-@item DBX_REGPARM_STABS_LETTER
+@defmac DBX_REGPARM_STABS_LETTER
The letter to use in DBX symbol data to identify a symbol as a parameter
passed in registers. DBX format does not customarily provide any way to
do this. The default is @code{'P'}.
+@end defmac
-@findex DBX_MEMPARM_STABS_LETTER
-@item DBX_MEMPARM_STABS_LETTER
-The letter to use in DBX symbol data to identify a symbol as a stack
-parameter. The default is @code{'p'}.
-
-@findex DBX_FUNCTION_FIRST
-@item DBX_FUNCTION_FIRST
+@defmac DBX_FUNCTION_FIRST
Define this macro if the DBX information for a function and its
arguments should precede the assembler code for the function. Normally,
in DBX format, the debugging information entirely follows the assembler
code.
-
-@findex DBX_LBRAC_FIRST
-@item DBX_LBRAC_FIRST
-Define this macro if the @code{N_LBRAC} symbol for a block should
-precede the debugging information for variables and functions defined in
-that block. Normally, in DBX format, the @code{N_LBRAC} symbol comes
-first.
-
-@findex DBX_BLOCKS_FUNCTION_RELATIVE
-@item DBX_BLOCKS_FUNCTION_RELATIVE
-Define this macro if the value of a symbol describing the scope of a
-block (@code{N_LBRAC} or @code{N_RBRAC}) should be relative to the start
-of the enclosing function. Normally, GCC uses an absolute address.
-
-@findex DBX_USE_BINCL
-@item DBX_USE_BINCL
+@end defmac
+
+@defmac DBX_BLOCKS_FUNCTION_RELATIVE
+Define this macro, with value 1, if the value of a symbol describing
+the scope of a block (@code{N_LBRAC} or @code{N_RBRAC}) should be
+relative to the start of the enclosing function. Normally, GCC uses
+an absolute address.
+@end defmac
+
+@defmac DBX_LINES_FUNCTION_RELATIVE
+Define this macro, with value 1, if the value of a symbol indicating
+the current line number (@code{N_SLINE}) should be relative to the
+start of the enclosing function. Normally, GCC uses an absolute address.
+@end defmac
+
+@defmac DBX_USE_BINCL
Define this macro if GCC should generate @code{N_BINCL} and
@code{N_EINCL} stabs for included header files, as on Sun systems. This
macro also directs GCC to output a type number as a pair of a file
number and a type number within the file. Normally, GCC does not
generate @code{N_BINCL} or @code{N_EINCL} stabs, and it outputs a single
number for a type number.
-@end table
+@end defmac
@node DBX Hooks
@subsection Open-Ended Hooks for DBX Format
@c prevent bad page break with this line
These are hooks for DBX format.
-@table @code
-@findex DBX_OUTPUT_LBRAC
-@item DBX_OUTPUT_LBRAC (@var{stream}, @var{name})
+@defmac DBX_OUTPUT_LBRAC (@var{stream}, @var{name})
Define this macro to say how to output to @var{stream} the debugging
information for the start of a scope level for variable names. The
argument @var{name} is the name of an assembler symbol (for use with
@code{assemble_name}) whose value is the address where the scope begins.
+@end defmac
-@findex DBX_OUTPUT_RBRAC
-@item DBX_OUTPUT_RBRAC (@var{stream}, @var{name})
+@defmac DBX_OUTPUT_RBRAC (@var{stream}, @var{name})
Like @code{DBX_OUTPUT_LBRAC}, but for the end of a scope level.
+@end defmac
-@findex DBX_OUTPUT_NFUN
-@item DBX_OUTPUT_NFUN (@var{stream}, @var{lscope_label}, @var{decl})
+@defmac DBX_OUTPUT_NFUN (@var{stream}, @var{lscope_label}, @var{decl})
Define this macro if the target machine requires special handling to
output an @code{N_FUN} entry for the function @var{decl}.
+@end defmac
-@findex DBX_OUTPUT_ENUM
-@item DBX_OUTPUT_ENUM (@var{stream}, @var{type})
-Define this macro if the target machine requires special handling to
-output an enumeration type. The definition should be a C statement
-(sans semicolon) to output the appropriate information to @var{stream}
-for the type @var{type}.
-
-@findex DBX_OUTPUT_FUNCTION_END
-@item DBX_OUTPUT_FUNCTION_END (@var{stream}, @var{function})
-Define this macro if the target machine requires special output at the
-end of the debugging information for a function. The definition should
-be a C statement (sans semicolon) to output the appropriate information
-to @var{stream}. @var{function} is the @code{FUNCTION_DECL} node for
-the function.
-
-@findex DBX_OUTPUT_STANDARD_TYPES
-@item DBX_OUTPUT_STANDARD_TYPES (@var{syms})
-Define this macro if you need to control the order of output of the
-standard data types at the beginning of compilation. The argument
-@var{syms} is a @code{tree} which is a chain of all the predefined
-global symbols, including names of data types.
-
-Normally, DBX output starts with definitions of the types for integers
-and characters, followed by all the other predefined types of the
-particular language in no particular order.
-
-On some machines, it is necessary to output different particular types
-first. To do this, define @code{DBX_OUTPUT_STANDARD_TYPES} to output
-those symbols in the necessary order. Any predefined types that you
-don't explicitly output will be output afterward in no particular order.
-
-Be careful not to define this macro so that it works only for C@. There
-are no global variables to access most of the built-in types, because
-another language may have another set of types. The way to output a
-particular type is to look through @var{syms} to see if you can find it.
-Here is an example:
-
-@smallexample
-@{
- tree decl;
- for (decl = syms; decl; decl = TREE_CHAIN (decl))
- if (!strcmp (IDENTIFIER_POINTER (DECL_NAME (decl)),
- "long int"))
- dbxout_symbol (decl);
- @dots{}
-@}
-@end smallexample
-
-@noindent
-This does nothing if the expected type does not exist.
-
-See the function @code{init_decl_processing} in @file{c-decl.c} to find
-the names to use for all the built-in C types.
+@defmac DBX_OUTPUT_SOURCE_LINE (@var{stream}, @var{line}, @var{counter})
+A C statement to output DBX debugging information before code for line
+number @var{line} of the current source file to the stdio stream
+@var{stream}. @var{counter} is the number of time the macro was
+invoked, including the current invocation; it is intended to generate
+unique labels in the assembly output.
-Here is another way of finding a particular type:
+This macro should not be defined if the default output is correct, or
+if it can be made correct by defining @code{DBX_LINES_FUNCTION_RELATIVE}.
+@end defmac
-@c this is still overfull. --mew 10feb93
-@smallexample
-@{
- tree decl;
- for (decl = syms; decl; decl = TREE_CHAIN (decl))
- if (TREE_CODE (decl) == TYPE_DECL
- && (TREE_CODE (TREE_TYPE (decl))
- == INTEGER_CST)
- && TYPE_PRECISION (TREE_TYPE (decl)) == 16
- && TYPE_UNSIGNED (TREE_TYPE (decl)))
-@group
- /* @r{This must be @code{unsigned short}.} */
- dbxout_symbol (decl);
- @dots{}
-@}
-@end group
-@end smallexample
-
-@findex NO_DBX_FUNCTION_END
-@item NO_DBX_FUNCTION_END
+@defmac NO_DBX_FUNCTION_END
Some stabs encapsulation formats (in particular ECOFF), cannot handle the
@code{.stabs "",N_FUN,,0,0,Lscope-function-1} gdb dbx extension construct.
On those machines, define this macro to turn this feature off without
disturbing the rest of the gdb extensions.
+@end defmac
-@end table
+@defmac NO_DBX_BNSYM_ENSYM
+Some assemblers cannot handle the @code{.stabd BNSYM/ENSYM,0,0} gdb dbx
+extension construct. On those machines, define this macro to turn this
+feature off without disturbing the rest of the gdb extensions.
+@end defmac
@node File Names and DBX
@subsection File Names in DBX Format
@c prevent bad page break with this line
This describes file names in DBX format.
-@table @code
-@findex DBX_WORKING_DIRECTORY
-@item DBX_WORKING_DIRECTORY
-Define this if DBX wants to have the current directory recorded in each
-object file.
-
-Note that the working directory is always recorded if GDB extensions are
-enabled.
-
-@findex DBX_OUTPUT_MAIN_SOURCE_FILENAME
-@item DBX_OUTPUT_MAIN_SOURCE_FILENAME (@var{stream}, @var{name})
+@defmac DBX_OUTPUT_MAIN_SOURCE_FILENAME (@var{stream}, @var{name})
A C statement to output DBX debugging information to the stdio stream
-@var{stream} which indicates that file @var{name} is the main source
+@var{stream}, which indicates that file @var{name} is the main source
file---the file specified as the input file for compilation.
This macro is called only once, at the beginning of compilation.
This macro need not be defined if the standard form of output
for DBX debugging information is appropriate.
-@findex DBX_OUTPUT_MAIN_SOURCE_DIRECTORY
-@item DBX_OUTPUT_MAIN_SOURCE_DIRECTORY (@var{stream}, @var{name})
-A C statement to output DBX debugging information to the stdio stream
-@var{stream} which indicates that the current directory during
-compilation is named @var{name}.
-
-This macro need not be defined if the standard form of output
-for DBX debugging information is appropriate.
-
-@findex DBX_OUTPUT_MAIN_SOURCE_FILE_END
-@item DBX_OUTPUT_MAIN_SOURCE_FILE_END (@var{stream}, @var{name})
+It may be necessary to refer to a label equal to the beginning of the
+text section. You can use @samp{assemble_name (stream, ltext_label_name)}
+to do so. If you do this, you must also set the variable
+@var{used_ltext_label_name} to @code{true}.
+@end defmac
+
+@defmac NO_DBX_MAIN_SOURCE_DIRECTORY
+Define this macro, with value 1, if GCC should not emit an indication
+of the current directory for compilation and current source language at
+the beginning of the file.
+@end defmac
+
+@defmac NO_DBX_GCC_MARKER
+Define this macro, with value 1, if GCC should not emit an indication
+that this object file was compiled by GCC@. The default is to emit
+an @code{N_OPT} stab at the beginning of every source file, with
+@samp{gcc2_compiled.} for the string and value 0.
+@end defmac
+
+@defmac DBX_OUTPUT_MAIN_SOURCE_FILE_END (@var{stream}, @var{name})
A C statement to output DBX debugging information at the end of
-compilation of the main source file @var{name}.
+compilation of the main source file @var{name}. Output should be
+written to the stdio stream @var{stream}.
If you don't define this macro, nothing special is output at the end
of compilation, which is correct for most machines.
+@end defmac
-@findex DBX_OUTPUT_SOURCE_FILENAME
-@item DBX_OUTPUT_SOURCE_FILENAME (@var{stream}, @var{name})
-A C statement to output DBX debugging information to the stdio stream
-@var{stream} which indicates that file @var{name} is the current source
-file. This output is generated each time input shifts to a different
-source file as a result of @samp{#include}, the end of an included file,
-or a @samp{#line} command.
-
-This macro need not be defined if the standard form of output
-for DBX debugging information is appropriate.
-@end table
+@defmac DBX_OUTPUT_NULL_N_SO_AT_MAIN_SOURCE_FILE_END
+Define this macro @emph{instead of} defining
+@code{DBX_OUTPUT_MAIN_SOURCE_FILE_END}, if what needs to be output at
+the end of compilation is a @code{N_SO} stab with an empty string,
+whose value is the highest absolute text address in the file.
+@end defmac
@need 2000
@node SDB and DWARF
@c prevent bad page break with this line
Here are macros for SDB and DWARF output.
-@table @code
-@findex SDB_DEBUGGING_INFO
-@item SDB_DEBUGGING_INFO
+@defmac SDB_DEBUGGING_INFO
Define this macro if GCC should produce COFF-style debugging output
for SDB in response to the @option{-g} option.
+@end defmac
-@findex DWARF_DEBUGGING_INFO
-@item DWARF_DEBUGGING_INFO
-Define this macro if GCC should produce dwarf format debugging output
-in response to the @option{-g} option.
-
-@findex DWARF2_DEBUGGING_INFO
-@item DWARF2_DEBUGGING_INFO
+@defmac DWARF2_DEBUGGING_INFO
Define this macro if GCC should produce dwarf version 2 format
debugging output in response to the @option{-g} option.
+@deftypefn {Target Hook} int TARGET_DWARF_CALLING_CONVENTION (tree @var{function})
+Define this to enable the dwarf attribute @code{DW_AT_calling_convention} to
+be emitted for each function. Instead of an integer return the enum
+value for the @code{DW_CC_} tag.
+@end deftypefn
+
To support optional call frame debugging information, you must also
define @code{INCOMING_RETURN_ADDR_RTX} and either set
@code{RTX_FRAME_RELATED_P} on the prologue insns if you use RTL for the
prologue, or call @code{dwarf2out_def_cfa} and @code{dwarf2out_reg_save}
as appropriate from @code{TARGET_ASM_FUNCTION_PROLOGUE} if you don't.
+@end defmac
-@findex DWARF2_FRAME_INFO
-@item DWARF2_FRAME_INFO
+@defmac DWARF2_FRAME_INFO
Define this macro to a nonzero value if GCC should always output
Dwarf 2 frame information. If @code{DWARF2_UNWIND_INFO}
(@pxref{Exception Region Output} is nonzero, GCC will output this
information not matter how you define @code{DWARF2_FRAME_INFO}.
+@end defmac
-@findex LINKER_DOES_NOT_WORK_WITH_DWARF2
-@item LINKER_DOES_NOT_WORK_WITH_DWARF2
-Define this macro if the linker does not work with Dwarf version 2.
-Normally, if the user specifies only @option{-ggdb} GCC will use Dwarf
-version 2 if available; this macro disables this. See the description
-of the @code{PREFERRED_DEBUGGING_TYPE} macro for more details.
-
-@findex DWARF2_GENERATE_TEXT_SECTION_LABEL
-@item DWARF2_GENERATE_TEXT_SECTION_LABEL
-By default, the Dwarf 2 debugging information generator will generate a
-label to mark the beginning of the text section. If it is better simply
-to use the name of the text section itself, rather than an explicit label,
-to indicate the beginning of the text section, define this macro to zero.
-
-@findex DWARF2_ASM_LINE_DEBUG_INFO
-@item DWARF2_ASM_LINE_DEBUG_INFO
+@defmac DWARF2_ASM_LINE_DEBUG_INFO
Define this macro to be a nonzero value if the assembler can generate Dwarf 2
line debug info sections. This will result in much more compact line number
tables, and hence is desirable if it works.
+@end defmac
+
+@defmac ASM_OUTPUT_DWARF_DELTA (@var{stream}, @var{size}, @var{label1}, @var{label2})
+A C statement to issue assembly directives that create a difference
+@var{lab1} minus @var{lab2}, using an integer of the given @var{size}.
+@end defmac
+
+@defmac ASM_OUTPUT_DWARF_OFFSET (@var{stream}, @var{size}, @var{label}, @var{section})
+A C statement to issue assembly directives that create a
+section-relative reference to the given @var{label}, using an integer of the
+given @var{size}. The label is known to be defined in the given @var{section}.
+@end defmac
+
+@defmac ASM_OUTPUT_DWARF_PCREL (@var{stream}, @var{size}, @var{label})
+A C statement to issue assembly directives that create a self-relative
+reference to the given @var{label}, using an integer of the given @var{size}.
+@end defmac
+
+@deftypefn {Target Hook} void TARGET_ASM_OUTPUT_DWARF_DTPREL (FILE *@var{FILE}, int @var{size}, rtx @var{x})
+If defined, this target hook is a function which outputs a DTP-relative
+reference to the given TLS symbol of the specified size.
+@end deftypefn
-@findex PUT_SDB_@dots{}
-@item PUT_SDB_@dots{}
+@defmac PUT_SDB_@dots{}
Define these macros to override the assembler syntax for the special
SDB assembler directives. See @file{sdbout.c} for a list of these
macros and their arguments. If the standard syntax is used, you need
not define them yourself.
+@end defmac
-@findex SDB_DELIM
-@item SDB_DELIM
+@defmac SDB_DELIM
Some assemblers do not support a semicolon as a delimiter, even between
SDB assembler directives. In that case, define this macro to be the
delimiter to use (usually @samp{\n}). It is not necessary to define
a new set of @code{PUT_SDB_@var{op}} macros if this is the only change
required.
+@end defmac
-@findex SDB_GENERATE_FAKE
-@item SDB_GENERATE_FAKE
-Define this macro to override the usual method of constructing a dummy
-name for anonymous structure and union types. See @file{sdbout.c} for
-more information.
-
-@findex SDB_ALLOW_UNKNOWN_REFERENCES
-@item SDB_ALLOW_UNKNOWN_REFERENCES
+@defmac SDB_ALLOW_UNKNOWN_REFERENCES
Define this macro to allow references to unknown structure,
union, or enumeration tags to be emitted. Standard COFF does not
allow handling of unknown references, MIPS ECOFF has support for
it.
+@end defmac
-@findex SDB_ALLOW_FORWARD_REFERENCES
-@item SDB_ALLOW_FORWARD_REFERENCES
+@defmac SDB_ALLOW_FORWARD_REFERENCES
Define this macro to allow references to structure, union, or
enumeration tags that have not yet been seen to be handled. Some
assemblers choke if forward tags are used, while some require it.
-@end table
+@end defmac
+
+@defmac SDB_OUTPUT_SOURCE_LINE (@var{stream}, @var{line})
+A C statement to output SDB debugging information before code for line
+number @var{line} of the current source file to the stdio stream
+@var{stream}. The default is to emit an @code{.ln} directive.
+@end defmac
@need 2000
@node VMS Debug
@c prevent bad page break with this line
Here are macros for VMS debug format.
-@table @code
-@findex VMS_DEBUGGING_INFO
-@item VMS_DEBUGGING_INFO
+@defmac VMS_DEBUGGING_INFO
Define this macro if GCC should produce debugging output for VMS
in response to the @option{-g} option. The default behavior for VMS
is to generate minimal debug info for a traceback in the absence of
@option{-g} unless explicitly overridden with @option{-g0}. This
behavior is controlled by @code{OPTIMIZATION_OPTIONS} and
@code{OVERRIDE_OPTIONS}.
-@end table
+@end defmac
-@node Cross-compilation
+@node Floating Point
@section Cross Compilation and Floating Point
@cindex cross compilation and floating point
@cindex floating point and cross compilation
-While all modern machines use 2's complement representation for integers,
+While all modern machines use twos-complement representation for integers,
there are a variety of representations for floating point numbers. This
means that in a cross-compiler the representation of floating point numbers
in the compiled program may be different from that used in the machine
doing the compilation.
-@findex atof
Because different representation systems may offer different amounts of
-range and precision, the cross compiler cannot safely use the host
-machine's floating point arithmetic. Therefore, floating point constants
-must be represented in the target machine's format. This means that the
-cross compiler cannot use @code{atof} to parse a floating point constant;
-it must have its own special routine to use instead. Also, constant
-folding must emulate the target machine's arithmetic (or must not be done
-at all).
-
-The macros in the following table should be defined only if you are cross
-compiling between different floating point formats.
-
-Otherwise, don't define them. Then default definitions will be set up which
-use @code{double} as the data type, @code{==} to test for equality, etc.
-
-You don't need to worry about how many times you use an operand of any
-of these macros. The compiler never uses operands which have side effects.
-
-@table @code
-@findex REAL_VALUE_TYPE
-@item REAL_VALUE_TYPE
-A macro for the C data type to be used to hold a floating point value
-in the target machine's format. Typically this would be a
-@code{struct} containing an array of @code{int}.
-
-@findex REAL_VALUES_EQUAL
-@item REAL_VALUES_EQUAL (@var{x}, @var{y})
-A macro for a C expression which compares for equality the two values,
-@var{x} and @var{y}, both of type @code{REAL_VALUE_TYPE}.
-
-@findex REAL_VALUES_LESS
-@item REAL_VALUES_LESS (@var{x}, @var{y})
-A macro for a C expression which tests whether @var{x} is less than
-@var{y}, both values being of type @code{REAL_VALUE_TYPE} and
-interpreted as floating point numbers in the target machine's
-representation.
-
-@findex REAL_VALUE_LDEXP
-@findex ldexp
-@item REAL_VALUE_LDEXP (@var{x}, @var{scale})
-A macro for a C expression which performs the standard library
-function @code{ldexp}, but using the target machine's floating point
-representation. Both @var{x} and the value of the expression have
-type @code{REAL_VALUE_TYPE}. The second argument, @var{scale}, is an
-integer.
-
-@findex REAL_VALUE_FIX
-@item REAL_VALUE_FIX (@var{x})
-A macro whose definition is a C expression to convert the target-machine
-floating point value @var{x} to a signed integer. @var{x} has type
-@code{REAL_VALUE_TYPE}.
-
-@findex REAL_VALUE_UNSIGNED_FIX
-@item REAL_VALUE_UNSIGNED_FIX (@var{x})
-A macro whose definition is a C expression to convert the target-machine
-floating point value @var{x} to an unsigned integer. @var{x} has type
-@code{REAL_VALUE_TYPE}.
-
-@findex REAL_VALUE_RNDZINT
-@item REAL_VALUE_RNDZINT (@var{x})
-A macro whose definition is a C expression to round the target-machine
-floating point value @var{x} towards zero to an integer value (but still
-as a floating point number). @var{x} has type @code{REAL_VALUE_TYPE},
-and so does the value.
-
-@findex REAL_VALUE_UNSIGNED_RNDZINT
-@item REAL_VALUE_UNSIGNED_RNDZINT (@var{x})
-A macro whose definition is a C expression to round the target-machine
-floating point value @var{x} towards zero to an unsigned integer value
-(but still represented as a floating point number). @var{x} has type
-@code{REAL_VALUE_TYPE}, and so does the value.
-
-@findex REAL_VALUE_ATOF
-@item REAL_VALUE_ATOF (@var{string}, @var{mode})
-A macro for a C expression which converts @var{string}, an expression of
-type @code{char *}, into a floating point number in the target machine's
-representation for mode @var{mode}. The value has type
-@code{REAL_VALUE_TYPE}.
-
-@findex REAL_INFINITY
-@item REAL_INFINITY
-Define this macro if infinity is a possible floating point value, and
-therefore division by 0 is legitimate.
-
-@findex REAL_VALUE_ISINF
-@findex isinf
-@item REAL_VALUE_ISINF (@var{x})
-A macro for a C expression which determines whether @var{x}, a floating
-point value, is infinity. The value has type @code{int}.
-By default, this is defined to call @code{isinf}.
-
-@findex REAL_VALUE_ISNAN
-@findex isnan
-@item REAL_VALUE_ISNAN (@var{x})
-A macro for a C expression which determines whether @var{x}, a floating
-point value, is a ``nan'' (not-a-number). The value has type
-@code{int}. By default, this is defined to call @code{isnan}.
-@end table
+range and precision, all floating point constants must be represented in
+the target machine's format. Therefore, the cross compiler cannot
+safely use the host machine's floating point arithmetic; it must emulate
+the target's arithmetic. To ensure consistency, GCC always uses
+emulation to work with floating point values, even when the host and
+target floating point formats are identical.
+
+The following macros are provided by @file{real.h} for the compiler to
+use. All parts of the compiler which generate or optimize
+floating-point calculations must use these macros. They may evaluate
+their operands more than once, so operands must not have side effects.
+
+@defmac REAL_VALUE_TYPE
+The C data type to be used to hold a floating point value in the target
+machine's format. Typically this is a @code{struct} containing an
+array of @code{HOST_WIDE_INT}, but all code should treat it as an opaque
+quantity.
+@end defmac
+
+@deftypefn Macro int REAL_VALUES_EQUAL (REAL_VALUE_TYPE @var{x}, REAL_VALUE_TYPE @var{y})
+Compares for equality the two values, @var{x} and @var{y}. If the target
+floating point format supports negative zeroes and/or NaNs,
+@samp{REAL_VALUES_EQUAL (-0.0, 0.0)} is true, and
+@samp{REAL_VALUES_EQUAL (NaN, NaN)} is false.
+@end deftypefn
-@cindex constant folding and floating point
-Define the following additional macros if you want to make floating
-point constant folding work while cross compiling. If you don't
-define them, cross compilation is still possible, but constant folding
-will not happen for floating point values.
-
-@table @code
-@findex REAL_ARITHMETIC
-@item REAL_ARITHMETIC (@var{output}, @var{code}, @var{x}, @var{y})
-A macro for a C statement which calculates an arithmetic operation of
-the two floating point values @var{x} and @var{y}, both of type
-@code{REAL_VALUE_TYPE} in the target machine's representation, to
-produce a result of the same type and representation which is stored
-in @var{output} (which will be a variable).
-
-The operation to be performed is specified by @var{code}, a tree code
-which will always be one of the following: @code{PLUS_EXPR},
-@code{MINUS_EXPR}, @code{MULT_EXPR}, @code{RDIV_EXPR},
-@code{MAX_EXPR}, @code{MIN_EXPR}.
-
-@cindex overflow while constant folding
-The expansion of this macro is responsible for checking for overflow.
-If overflow happens, the macro expansion should execute the statement
-@code{return 0;}, which indicates the inability to perform the
-arithmetic operation requested.
-
-@findex REAL_VALUE_NEGATE
-@item REAL_VALUE_NEGATE (@var{x})
-A macro for a C expression which returns the negative of the floating
-point value @var{x}. Both @var{x} and the value of the expression
-have type @code{REAL_VALUE_TYPE} and are in the target machine's
-floating point representation.
-
-There is no way for this macro to report overflow, since overflow
-can't happen in the negation operation.
-
-@findex REAL_VALUE_TRUNCATE
-@item REAL_VALUE_TRUNCATE (@var{mode}, @var{x})
-A macro for a C expression which converts the floating point value
-@var{x} to mode @var{mode}.
-
-Both @var{x} and the value of the expression are in the target machine's
-floating point representation and have type @code{REAL_VALUE_TYPE}.
-However, the value should have an appropriate bit pattern to be output
-properly as a floating constant whose precision accords with mode
-@var{mode}.
-
-There is no way for this macro to report overflow.
-
-@findex REAL_VALUE_TO_INT
-@item REAL_VALUE_TO_INT (@var{low}, @var{high}, @var{x})
-A macro for a C expression which converts a floating point value
-@var{x} into a double-precision integer which is then stored into
-@var{low} and @var{high}, two variables of type @var{int}.
-
-@item REAL_VALUE_FROM_INT (@var{x}, @var{low}, @var{high}, @var{mode})
-@findex REAL_VALUE_FROM_INT
-A macro for a C expression which converts a double-precision integer
-found in @var{low} and @var{high}, two variables of type @var{int},
-into a floating point value which is then stored into @var{x}.
-The value is in the target machine's representation for mode @var{mode}
-and has the type @code{REAL_VALUE_TYPE}.
-@end table
+@deftypefn Macro int REAL_VALUES_LESS (REAL_VALUE_TYPE @var{x}, REAL_VALUE_TYPE @var{y})
+Tests whether @var{x} is less than @var{y}.
+@end deftypefn
+
+@deftypefn Macro HOST_WIDE_INT REAL_VALUE_FIX (REAL_VALUE_TYPE @var{x})
+Truncates @var{x} to a signed integer, rounding toward zero.
+@end deftypefn
+
+@deftypefn Macro {unsigned HOST_WIDE_INT} REAL_VALUE_UNSIGNED_FIX (REAL_VALUE_TYPE @var{x})
+Truncates @var{x} to an unsigned integer, rounding toward zero. If
+@var{x} is negative, returns zero.
+@end deftypefn
+
+@deftypefn Macro REAL_VALUE_TYPE REAL_VALUE_ATOF (const char *@var{string}, enum machine_mode @var{mode})
+Converts @var{string} into a floating point number in the target machine's
+representation for mode @var{mode}. This routine can handle both
+decimal and hexadecimal floating point constants, using the syntax
+defined by the C language for both.
+@end deftypefn
+
+@deftypefn Macro int REAL_VALUE_NEGATIVE (REAL_VALUE_TYPE @var{x})
+Returns 1 if @var{x} is negative (including negative zero), 0 otherwise.
+@end deftypefn
+
+@deftypefn Macro int REAL_VALUE_ISINF (REAL_VALUE_TYPE @var{x})
+Determines whether @var{x} represents infinity (positive or negative).
+@end deftypefn
+
+@deftypefn Macro int REAL_VALUE_ISNAN (REAL_VALUE_TYPE @var{x})
+Determines whether @var{x} represents a ``NaN'' (not-a-number).
+@end deftypefn
+
+@deftypefn Macro void REAL_ARITHMETIC (REAL_VALUE_TYPE @var{output}, enum tree_code @var{code}, REAL_VALUE_TYPE @var{x}, REAL_VALUE_TYPE @var{y})
+Calculates an arithmetic operation on the two floating point values
+@var{x} and @var{y}, storing the result in @var{output} (which must be a
+variable).
+
+The operation to be performed is specified by @var{code}. Only the
+following codes are supported: @code{PLUS_EXPR}, @code{MINUS_EXPR},
+@code{MULT_EXPR}, @code{RDIV_EXPR}, @code{MAX_EXPR}, @code{MIN_EXPR}.
+
+If @code{REAL_ARITHMETIC} is asked to evaluate division by zero and the
+target's floating point format cannot represent infinity, it will call
+@code{abort}. Callers should check for this situation first, using
+@code{MODE_HAS_INFINITIES}. @xref{Storage Layout}.
+@end deftypefn
+
+@deftypefn Macro REAL_VALUE_TYPE REAL_VALUE_NEGATE (REAL_VALUE_TYPE @var{x})
+Returns the negative of the floating point value @var{x}.
+@end deftypefn
+
+@deftypefn Macro REAL_VALUE_TYPE REAL_VALUE_ABS (REAL_VALUE_TYPE @var{x})
+Returns the absolute value of @var{x}.
+@end deftypefn
+
+@deftypefn Macro REAL_VALUE_TYPE REAL_VALUE_TRUNCATE (REAL_VALUE_TYPE @var{mode}, enum machine_mode @var{x})
+Truncates the floating point value @var{x} to fit in @var{mode}. The
+return value is still a full-size @code{REAL_VALUE_TYPE}, but it has an
+appropriate bit pattern to be output as a floating constant whose
+precision accords with mode @var{mode}.
+@end deftypefn
+
+@deftypefn Macro void REAL_VALUE_TO_INT (HOST_WIDE_INT @var{low}, HOST_WIDE_INT @var{high}, REAL_VALUE_TYPE @var{x})
+Converts a floating point value @var{x} into a double-precision integer
+which is then stored into @var{low} and @var{high}. If the value is not
+integral, it is truncated.
+@end deftypefn
+
+@deftypefn Macro void REAL_VALUE_FROM_INT (REAL_VALUE_TYPE @var{x}, HOST_WIDE_INT @var{low}, HOST_WIDE_INT @var{high}, enum machine_mode @var{mode})
+Converts a double-precision integer found in @var{low} and @var{high},
+into a floating point value which is then stored into @var{x}. The
+value is truncated to fit in mode @var{mode}.
+@end deftypefn
@node Mode Switching
@section Mode Switching Instructions
@cindex mode switching
The following macros control mode switching optimizations:
-@table @code
-@findex OPTIMIZE_MODE_SWITCHING
-@item OPTIMIZE_MODE_SWITCHING (@var{entity})
+@defmac OPTIMIZE_MODE_SWITCHING (@var{entity})
Define this macro if the port needs extra instructions inserted for mode
switching in an optimizing compilation.
operation, this bit has to be set. Changing the PR bit requires a general
purpose register as a scratch register, hence these FPSCR sets have to
be inserted before reload, i.e.@: you can't put this into instruction emitting
-or @code{MACHINE_DEPENDENT_REORG}.
+or @code{TARGET_MACHINE_DEPENDENT_REORG}.
You can have multiple entities that are mode-switched, and select at run time
which entities actually need it. @code{OPTIMIZE_MODE_SWITCHING} should
If you define this macro, you also have to define
@code{NUM_MODES_FOR_MODE_SWITCHING}, @code{MODE_NEEDED},
@code{MODE_PRIORITY_TO_MODE} and @code{EMIT_MODE_SET}.
-@code{NORMAL_MODE} is optional.
+@code{MODE_AFTER}, @code{MODE_ENTRY}, and @code{MODE_EXIT}
+are optional.
+@end defmac
-@findex NUM_MODES_FOR_MODE_SWITCHING
-@item NUM_MODES_FOR_MODE_SWITCHING
+@defmac NUM_MODES_FOR_MODE_SWITCHING
If you define @code{OPTIMIZE_MODE_SWITCHING}, you have to define this as
initializer for an array of integers. Each initializer element
N refers to an entity that needs mode switching, and specifies the number
of different modes that might need to be set for this entity.
-The position of the initializer in the initializer - starting counting at
-zero - determines the integer that is used to refer to the mode-switched
+The position of the initializer in the initializer---starting counting at
+zero---determines the integer that is used to refer to the mode-switched
entity in question.
In macros that take mode arguments / yield a mode result, modes are
represented as numbers 0 @dots{} N @minus{} 1. N is used to specify that no mode
switch is needed / supplied.
+@end defmac
-@findex MODE_NEEDED
-@item MODE_NEEDED (@var{entity}, @var{insn})
+@defmac MODE_NEEDED (@var{entity}, @var{insn})
@var{entity} is an integer specifying a mode-switched entity. If
@code{OPTIMIZE_MODE_SWITCHING} is defined, you must define this macro to
return an integer value not larger than the corresponding element in
@code{NUM_MODES_FOR_MODE_SWITCHING}, to denote the mode that @var{entity} must
be switched into prior to the execution of @var{insn}.
+@end defmac
+
+@defmac MODE_AFTER (@var{mode}, @var{insn})
+If this macro is defined, it is evaluated for every @var{insn} during
+mode switching. It determines the mode that an insn results in (if
+different from the incoming mode).
+@end defmac
-@findex NORMAL_MODE
-@item NORMAL_MODE (@var{entity})
+@defmac MODE_ENTRY (@var{entity})
If this macro is defined, it is evaluated for every @var{entity} that needs
mode switching. It should evaluate to an integer, which is a mode that
-@var{entity} is assumed to be switched to at function entry and exit.
+@var{entity} is assumed to be switched to at function entry. If @code{MODE_ENTRY}
+is defined then @code{MODE_EXIT} must be defined.
+@end defmac
-@findex MODE_PRIORITY_TO_MODE
-@item MODE_PRIORITY_TO_MODE (@var{entity}, @var{n})
+@defmac MODE_EXIT (@var{entity})
+If this macro is defined, it is evaluated for every @var{entity} that needs
+mode switching. It should evaluate to an integer, which is a mode that
+@var{entity} is assumed to be switched to at function exit. If @code{MODE_EXIT}
+is defined then @code{MODE_ENTRY} must be defined.
+@end defmac
+
+@defmac MODE_PRIORITY_TO_MODE (@var{entity}, @var{n})
This macro specifies the order in which modes for @var{entity} are processed.
0 is the highest priority, @code{NUM_MODES_FOR_MODE_SWITCHING[@var{entity}] - 1} the
lowest. The value of the macro should be an integer designating a mode
for @var{entity}. For any fixed @var{entity}, @code{mode_priority_to_mode}
(@var{entity}, @var{n}) shall be a bijection in 0 @dots{}
@code{num_modes_for_mode_switching[@var{entity}] - 1}.
+@end defmac
-@findex EMIT_MODE_SET
-@item EMIT_MODE_SET (@var{entity}, @var{mode}, @var{hard_regs_live})
+@defmac EMIT_MODE_SET (@var{entity}, @var{mode}, @var{hard_regs_live})
Generate one or more insns to set @var{entity} to @var{mode}.
@var{hard_reg_live} is the set of hard registers live at the point where
the insn(s) are to be inserted.
-@end table
+@end defmac
@node Target Attributes
@section Defining target-specific uses of @code{__attribute__}
call @code{merge_attributes} to handle machine-independent merging.
@findex TARGET_DLLIMPORT_DECL_ATTRIBUTES
-If the only target-specific handling you require is @samp{dllimport} for
-Windows targets, you should define the macro
-@code{TARGET_DLLIMPORT_DECL_ATTRIBUTES}. This links in a function
-called @code{merge_dllimport_decl_attributes} which can then be defined
-as the expansion of @code{TARGET_MERGE_DECL_ATTRIBUTES}. This is done
-in @file{i386/cygwin.h} and @file{i386/i386.c}, for example.
+If the only target-specific handling you require is @samp{dllimport}
+for Microsoft Windows targets, you should define the macro
+@code{TARGET_DLLIMPORT_DECL_ATTRIBUTES} to @code{1}. The compiler
+will then define a function called
+@code{merge_dllimport_decl_attributes} which can then be defined as
+the expansion of @code{TARGET_MERGE_DECL_ATTRIBUTES}. You can also
+add @code{handle_dll_attribute} in the attribute table for your port
+to perform initial processing of the @samp{dllimport} and
+@samp{dllexport} attributes. This is done in @file{i386/cygwin.h} and
+@file{i386/i386.c}, for example.
@end deftypefn
+@deftypefn {Target Hook} bool TARGET_VALID_DLLIMPORT_ATTRIBUTE_P (tree @var{decl})
+@var{decl} is a variable or function with @code{__attribute__((dllimport))}
+specified. Use this hook if the target needs to add extra validation
+checks to @code{handle_dll_attribute}.
+@end deftypefn
+
+@defmac TARGET_DECLSPEC
+Define this macro to a nonzero value if you want to treat
+@code{__declspec(X)} as equivalent to @code{__attribute((X))}. By
+default, this behavior is enabled only for targets that define
+@code{TARGET_DLLIMPORT_DECL_ATTRIBUTES}. The current implementation
+of @code{__declspec} is via a built-in macro, but you should not rely
+on this implementation detail.
+@end defmac
+
@deftypefn {Target Hook} void TARGET_INSERT_ATTRIBUTES (tree @var{node}, tree *@var{attr_ptr})
Define this target hook if you want to be able to add attributes to a decl
when it is being created. This is normally useful for back ends which
target specific attribute attached to it, it will not be inlined.
@end deftypefn
-@node Misc
-@section Miscellaneous Parameters
-@cindex parameters, miscellaneous
+@deftypefn {Target Hook} bool TARGET_VALID_OPTION_ATTRIBUTE_P (tree @var{fndecl}, tree @var{name}, tree @var{args}, int @var{flags})
+This hook is called to parse the @code{attribute(option("..."))}, and
+it allows the function to set different target machine compile time
+options for the current function that might be different than the
+options specified on the command line. The hook should return
+@code{true} if the options are valid.
-@c prevent bad page break with this line
-Here are several miscellaneous parameters.
+The hook should set the @var{DECL_FUNCTION_SPECIFIC_TARGET} field in
+the function declaration to hold a pointer to a target specific
+@var{struct cl_target_option} structure.
+@end deftypefn
+
+@deftypefn {Target Hook} void TARGET_OPTION_SAVE (struct cl_target_option *@var{ptr})
+This hook is called to save any additional target specific information
+in the @var{struct cl_target_option} structure for function specific
+options.
+@xref{Option file format}.
+@end deftypefn
+
+@deftypefn {Target Hook} void TARGET_OPTION_RESTORE (struct cl_target_option *@var{ptr})
+This hook is called to restore any additional target specific
+information in the @var{struct cl_target_option} structure for
+function specific options.
+@end deftypefn
+
+@deftypefn {Target Hook} void TARGET_OPTION_PRINT (struct cl_target_option *@var{ptr})
+This hook is called to print any additional target specific
+information in the @var{struct cl_target_option} structure for
+function specific options.
+@end deftypefn
+
+@deftypefn {Target Hook} bool TARGET_OPTION_PRAGMA_PARSE (target @var{args})
+This target hook parses the options for @code{#pragma GCC option} to
+set the machine specific options for functions that occur later in the
+input stream. The options should be the same as handled by the
+@code{TARGET_VALID_OPTION_ATTRIBUTE_P} hook.
+@end deftypefn
-@table @code
-@item PREDICATE_CODES
-@findex PREDICATE_CODES
-Define this if you have defined special-purpose predicates in the file
-@file{@var{machine}.c}. This macro is called within an initializer of an
-array of structures. The first field in the structure is the name of a
-predicate and the second field is an array of rtl codes. For each
-predicate, list all rtl codes that can be in expressions matched by the
-predicate. The list should have a trailing comma. Here is an example
-of two entries in the list for a typical RISC machine:
+@deftypefn {Target Hook} bool TARGET_CAN_INLINE_P (tree @var{caller}, tree @var{callee})
+This target hook returns @code{false} if the @var{caller} function
+cannot inline @var{callee}, based on target specific information. By
+default, inlining is not allowed if the callee function has function
+specific target options and the caller does not use the same options.
+@end deftypefn
+
+@node Emulated TLS
+@section Emulating TLS
+@cindex Emulated TLS
+
+For targets whose psABI does not provide Thread Local Storage via
+specific relocations and instruction sequences, an emulation layer is
+used. A set of target hooks allows this emulation layer to be
+configured for the requirements of a particular target. For instance
+the psABI may in fact specify TLS support in terms of an emulation
+layer.
+
+The emulation layer works by creating a control object for every TLS
+object. To access the TLS object, a lookup function is provided
+which, when given the address of the control object, will return the
+address of the current thread's instance of the TLS object.
+
+@deftypevr {Target Hook} {const char *} TARGET_EMUTLS_GET_ADDRESS
+Contains the name of the helper function that uses a TLS control
+object to locate a TLS instance. The default causes libgcc's
+emulated TLS helper function to be used.
+@end deftypevr
+
+@deftypevr {Target Hook} {const char *} TARGET_EMUTLS_REGISTER_COMMON
+Contains the name of the helper function that should be used at
+program startup to register TLS objects that are implicitly
+initialized to zero. If this is @code{NULL}, all TLS objects will
+have explicit initializers. The default causes libgcc's emulated TLS
+registration function to be used.
+@end deftypevr
+
+@deftypevr {Target Hook} {const char *} TARGET_EMUTLS_VAR_SECTION
+Contains the name of the section in which TLS control variables should
+be placed. The default of @code{NULL} allows these to be placed in
+any section.
+@end deftypevr
+
+@deftypevr {Target Hook} {const char *} TARGET_EMUTLS_TMPL_SECTION
+Contains the name of the section in which TLS initializers should be
+placed. The default of @code{NULL} allows these to be placed in any
+section.
+@end deftypevr
+
+@deftypevr {Target Hook} {const char *} TARGET_EMUTLS_VAR_PREFIX
+Contains the prefix to be prepended to TLS control variable names.
+The default of @code{NULL} uses a target-specific prefix.
+@end deftypevr
+
+@deftypevr {Target Hook} {const char *} TARGET_EMUTLS_TMPL_PREFIX
+Contains the prefix to be prepended to TLS initializer objects. The
+default of @code{NULL} uses a target-specific prefix.
+@end deftypevr
+
+@deftypefn {Target Hook} tree TARGET_EMUTLS_VAR_FIELDS (tree @var{type}, tree *@var{name})
+Specifies a function that generates the FIELD_DECLs for a TLS control
+object type. @var{type} is the RECORD_TYPE the fields are for and
+@var{name} should be filled with the structure tag, if the default of
+@code{__emutls_object} is unsuitable. The default creates a type suitable
+for libgcc's emulated TLS function.
+@end deftypefn
+
+@deftypefn {Target Hook} tree TARGET_EMUTLS_VAR_INIT (tree @var{var}, tree @var{decl}, tree @var{tmpl_addr})
+Specifies a function that generates the CONSTRUCTOR to initialize a
+TLS control object. @var{var} is the TLS control object, @var{decl}
+is the TLS object and @var{tmpl_addr} is the address of the
+initializer. The default initializes libgcc's emulated TLS control object.
+@end deftypefn
+
+@deftypevr {Target Hook} {bool} TARGET_EMUTLS_VAR_ALIGN_FIXED
+Specifies whether the alignment of TLS control variable objects is
+fixed and should not be increased as some backends may do to optimize
+single objects. The default is false.
+@end deftypevr
+
+@deftypevr {Target Hook} {bool} TARGET_EMUTLS_DEBUG_FORM_TLS_ADDRESS
+Specifies whether a DWARF @code{DW_OP_form_tls_address} location descriptor
+may be used to describe emulated TLS control objects.
+@end deftypevr
+
+@node MIPS Coprocessors
+@section Defining coprocessor specifics for MIPS targets.
+@cindex MIPS coprocessor-definition macros
+
+The MIPS specification allows MIPS implementations to have as many as 4
+coprocessors, each with as many as 32 private registers. GCC supports
+accessing these registers and transferring values between the registers
+and memory using asm-ized variables. For example:
@smallexample
-#define PREDICATE_CODES \
- @{"gen_reg_rtx_operand", @{SUBREG, REG@}@}, \
- @{"reg_or_short_cint_operand", @{SUBREG, REG, CONST_INT@}@},
+ register unsigned int cp0count asm ("c0r1");
+ unsigned int d;
+
+ d = cp0count + 3;
@end smallexample
-Defining this macro does not affect the generated code (however,
-incorrect definitions that omit an rtl code that may be matched by the
-predicate can cause the compiler to malfunction). Instead, it allows
-the table built by @file{genrecog} to be more compact and efficient,
-thus speeding up the compiler. The most important predicates to include
-in the list specified by this macro are those used in the most insn
-patterns.
-
-For each predicate function named in @code{PREDICATE_CODES}, a
-declaration will be generated in @file{insn-codes.h}.
-
-@item SPECIAL_MODE_PREDICATES
-@findex SPECIAL_MODE_PREDICATES
-Define this if you have special predicates that know special things
-about modes. Genrecog will warn about certain forms of
-@code{match_operand} without a mode; if the operand predicate is
-listed in @code{SPECIAL_MODE_PREDICATES}, the warning will be
-suppressed.
-
-Here is an example from the IA-32 port (@code{ext_register_operand}
-specially checks for @code{HImode} or @code{SImode} in preparation
-for a byte extraction from @code{%ah} etc.).
+(``c0r1'' is the default name of register 1 in coprocessor 0; alternate
+names may be added as described below, or the default names may be
+overridden entirely in @code{SUBTARGET_CONDITIONAL_REGISTER_USAGE}.)
+Coprocessor registers are assumed to be epilogue-used; sets to them will
+be preserved even if it does not appear that the register is used again
+later in the function.
+
+Another note: according to the MIPS spec, coprocessor 1 (if present) is
+the FPU@. One accesses COP1 registers through standard mips
+floating-point support; they are not included in this mechanism.
+
+There is one macro used in defining the MIPS coprocessor interface which
+you may want to override in subtargets; it is described below.
+
+@defmac ALL_COP_ADDITIONAL_REGISTER_NAMES
+A comma-separated list (with leading comma) of pairs describing the
+alternate names of coprocessor registers. The format of each entry should be
@smallexample
-#define SPECIAL_MODE_PREDICATES \
- "ext_register_operand",
+@{ @var{alternatename}, @var{register_number}@}
@end smallexample
+Default: empty.
+@end defmac
+
+@node PCH Target
+@section Parameters for Precompiled Header Validity Checking
+@cindex parameters, precompiled headers
+
+@deftypefn {Target Hook} void *TARGET_GET_PCH_VALIDITY (size_t *@var{sz})
+This hook returns the data needed by @code{TARGET_PCH_VALID_P} and sets
+@samp{*@var{sz}} to the size of the data in bytes.
+@end deftypefn
+
+@deftypefn {Target Hook} const char *TARGET_PCH_VALID_P (const void *@var{data}, size_t @var{sz})
+This hook checks whether the options used to create a PCH file are
+compatible with the current settings. It returns @code{NULL}
+if so and a suitable error message if not. Error messages will
+be presented to the user and must be localized using @samp{_(@var{msg})}.
-@findex CASE_VECTOR_MODE
-@item CASE_VECTOR_MODE
+@var{data} is the data that was returned by @code{TARGET_GET_PCH_VALIDITY}
+when the PCH file was created and @var{sz} is the size of that data in bytes.
+It's safe to assume that the data was created by the same version of the
+compiler, so no format checking is needed.
+
+The default definition of @code{default_pch_valid_p} should be
+suitable for most targets.
+@end deftypefn
+
+@deftypefn {Target Hook} const char *TARGET_CHECK_PCH_TARGET_FLAGS (int @var{pch_flags})
+If this hook is nonnull, the default implementation of
+@code{TARGET_PCH_VALID_P} will use it to check for compatible values
+of @code{target_flags}. @var{pch_flags} specifies the value that
+@code{target_flags} had when the PCH file was created. The return
+value is the same as for @code{TARGET_PCH_VALID_P}.
+@end deftypefn
+
+@node C++ ABI
+@section C++ ABI parameters
+@cindex parameters, c++ abi
+
+@deftypefn {Target Hook} tree TARGET_CXX_GUARD_TYPE (void)
+Define this hook to override the integer type used for guard variables.
+These are used to implement one-time construction of static objects. The
+default is long_long_integer_type_node.
+@end deftypefn
+
+@deftypefn {Target Hook} bool TARGET_CXX_GUARD_MASK_BIT (void)
+This hook determines how guard variables are used. It should return
+@code{false} (the default) if first byte should be used. A return value of
+@code{true} indicates the least significant bit should be used.
+@end deftypefn
+
+@deftypefn {Target Hook} tree TARGET_CXX_GET_COOKIE_SIZE (tree @var{type})
+This hook returns the size of the cookie to use when allocating an array
+whose elements have the indicated @var{type}. Assumes that it is already
+known that a cookie is needed. The default is
+@code{max(sizeof (size_t), alignof(type))}, as defined in section 2.7 of the
+IA64/Generic C++ ABI@.
+@end deftypefn
+
+@deftypefn {Target Hook} bool TARGET_CXX_COOKIE_HAS_SIZE (void)
+This hook should return @code{true} if the element size should be stored in
+array cookies. The default is to return @code{false}.
+@end deftypefn
+
+@deftypefn {Target Hook} int TARGET_CXX_IMPORT_EXPORT_CLASS (tree @var{type}, int @var{import_export})
+If defined by a backend this hook allows the decision made to export
+class @var{type} to be overruled. Upon entry @var{import_export}
+will contain 1 if the class is going to be exported, @minus{}1 if it is going
+to be imported and 0 otherwise. This function should return the
+modified value and perform any other actions necessary to support the
+backend's targeted operating system.
+@end deftypefn
+
+@deftypefn {Target Hook} bool TARGET_CXX_CDTOR_RETURNS_THIS (void)
+This hook should return @code{true} if constructors and destructors return
+the address of the object created/destroyed. The default is to return
+@code{false}.
+@end deftypefn
+
+@deftypefn {Target Hook} bool TARGET_CXX_KEY_METHOD_MAY_BE_INLINE (void)
+This hook returns true if the key method for a class (i.e., the method
+which, if defined in the current translation unit, causes the virtual
+table to be emitted) may be an inline function. Under the standard
+Itanium C++ ABI the key method may be an inline function so long as
+the function is not declared inline in the class definition. Under
+some variants of the ABI, an inline function can never be the key
+method. The default is to return @code{true}.
+@end deftypefn
+
+@deftypefn {Target Hook} void TARGET_CXX_DETERMINE_CLASS_DATA_VISIBILITY (tree @var{decl})
+@var{decl} is a virtual table, virtual table table, typeinfo object,
+or other similar implicit class data object that will be emitted with
+external linkage in this translation unit. No ELF visibility has been
+explicitly specified. If the target needs to specify a visibility
+other than that of the containing class, use this hook to set
+@code{DECL_VISIBILITY} and @code{DECL_VISIBILITY_SPECIFIED}.
+@end deftypefn
+
+@deftypefn {Target Hook} bool TARGET_CXX_CLASS_DATA_ALWAYS_COMDAT (void)
+This hook returns true (the default) if virtual tables and other
+similar implicit class data objects are always COMDAT if they have
+external linkage. If this hook returns false, then class data for
+classes whose virtual table will be emitted in only one translation
+unit will not be COMDAT.
+@end deftypefn
+
+@deftypefn {Target Hook} bool TARGET_CXX_LIBRARY_RTTI_COMDAT (void)
+This hook returns true (the default) if the RTTI information for
+the basic types which is defined in the C++ runtime should always
+be COMDAT, false if it should not be COMDAT.
+@end deftypefn
+
+@deftypefn {Target Hook} bool TARGET_CXX_USE_AEABI_ATEXIT (void)
+This hook returns true if @code{__aeabi_atexit} (as defined by the ARM EABI)
+should be used to register static destructors when @option{-fuse-cxa-atexit}
+is in effect. The default is to return false to use @code{__cxa_atexit}.
+@end deftypefn
+
+@deftypefn {Target Hook} bool TARGET_CXX_USE_ATEXIT_FOR_CXA_ATEXIT (void)
+This hook returns true if the target @code{atexit} function can be used
+in the same manner as @code{__cxa_atexit} to register C++ static
+destructors. This requires that @code{atexit}-registered functions in
+shared libraries are run in the correct order when the libraries are
+unloaded. The default is to return false.
+@end deftypefn
+
+@deftypefn {Target Hook} void TARGET_CXX_ADJUST_CLASS_AT_DEFINITION (tree @var{type})
+@var{type} is a C++ class (i.e., RECORD_TYPE or UNION_TYPE) that has just been
+defined. Use this hook to make adjustments to the class (eg, tweak
+visibility or perform any other required target modifications).
+@end deftypefn
+
+@node Misc
+@section Miscellaneous Parameters
+@cindex parameters, miscellaneous
+
+@c prevent bad page break with this line
+Here are several miscellaneous parameters.
+
+@defmac HAS_LONG_COND_BRANCH
+Define this boolean macro to indicate whether or not your architecture
+has conditional branches that can span all of memory. It is used in
+conjunction with an optimization that partitions hot and cold basic
+blocks into separate sections of the executable. If this macro is
+set to false, gcc will convert any conditional branches that attempt
+to cross between sections into unconditional branches or indirect jumps.
+@end defmac
+
+@defmac HAS_LONG_UNCOND_BRANCH
+Define this boolean macro to indicate whether or not your architecture
+has unconditional branches that can span all of memory. It is used in
+conjunction with an optimization that partitions hot and cold basic
+blocks into separate sections of the executable. If this macro is
+set to false, gcc will convert any unconditional branches that attempt
+to cross between sections into indirect jumps.
+@end defmac
+
+@defmac CASE_VECTOR_MODE
An alias for a machine mode name. This is the machine mode that
elements of a jump-table should have.
+@end defmac
-@findex CASE_VECTOR_SHORTEN_MODE
-@item CASE_VECTOR_SHORTEN_MODE (@var{min_offset}, @var{max_offset}, @var{body})
+@defmac CASE_VECTOR_SHORTEN_MODE (@var{min_offset}, @var{max_offset}, @var{body})
Optional: return the preferred mode for an @code{addr_diff_vec}
when the minimum and maximum offset are known. If you define this,
it enables extra code in branch shortening to deal with @code{addr_diff_vec}.
-To make this work, you also have to define INSN_ALIGN and
+To make this work, you also have to define @code{INSN_ALIGN} and
make the alignment for @code{addr_diff_vec} explicit.
The @var{body} argument is provided so that the offset_unsigned and scale
flags can be updated.
+@end defmac
-@findex CASE_VECTOR_PC_RELATIVE
-@item CASE_VECTOR_PC_RELATIVE
+@defmac CASE_VECTOR_PC_RELATIVE
Define this macro to be a C expression to indicate when jump-tables
-should contain relative addresses. If jump-tables never contain
-relative addresses, then you need not define this macro.
+should contain relative addresses. You need not define this macro if
+jump-tables never contain relative addresses, or jump-tables should
+contain relative addresses only when @option{-fPIC} or @option{-fPIC}
+is in effect.
+@end defmac
-@findex CASE_DROPS_THROUGH
-@item CASE_DROPS_THROUGH
-Define this if control falls through a @code{case} insn when the index
-value is out of range. This means the specified default-label is
-actually ignored by the @code{case} insn proper.
-
-@findex CASE_VALUES_THRESHOLD
-@item CASE_VALUES_THRESHOLD
+@defmac CASE_VALUES_THRESHOLD
Define this to be the smallest number of different values for which it
is best to use a jump-table instead of a tree of conditional branches.
The default is four for machines with a @code{casesi} instruction and
five otherwise. This is best for most machines.
-
-@findex WORD_REGISTER_OPERATIONS
-@item WORD_REGISTER_OPERATIONS
+@end defmac
+
+@defmac CASE_USE_BIT_TESTS
+Define this macro to be a C expression to indicate whether C switch
+statements may be implemented by a sequence of bit tests. This is
+advantageous on processors that can efficiently implement left shift
+of 1 by the number of bits held in a register, but inappropriate on
+targets that would require a loop. By default, this macro returns
+@code{true} if the target defines an @code{ashlsi3} pattern, and
+@code{false} otherwise.
+@end defmac
+
+@defmac WORD_REGISTER_OPERATIONS
Define this macro if operations between registers with integral mode
smaller than a word are always performed on the entire register.
Most RISC machines have this property and most CISC machines do not.
+@end defmac
-@findex LOAD_EXTEND_OP
-@item LOAD_EXTEND_OP (@var{mode})
+@defmac LOAD_EXTEND_OP (@var{mem_mode})
Define this macro to be a C expression indicating when insns that read
-memory in @var{mode}, an integral mode narrower than a word, set the
-bits outside of @var{mode} to be either the sign-extension or the
+memory in @var{mem_mode}, an integral mode narrower than a word, set the
+bits outside of @var{mem_mode} to be either the sign-extension or the
zero-extension of the data read. Return @code{SIGN_EXTEND} for values
-of @var{mode} for which the
+of @var{mem_mode} for which the
insn sign-extends, @code{ZERO_EXTEND} for which it zero-extends, and
-@code{NIL} for other modes.
+@code{UNKNOWN} for other modes.
-This macro is not called with @var{mode} non-integral or with a width
+This macro is not called with @var{mem_mode} non-integral or with a width
greater than or equal to @code{BITS_PER_WORD}, so you may return any
value in this case. Do not define this macro if it would always return
-@code{NIL}. On machines where this macro is defined, you will normally
+@code{UNKNOWN}. On machines where this macro is defined, you will normally
define it as the constant @code{SIGN_EXTEND} or @code{ZERO_EXTEND}.
-@findex SHORT_IMMEDIATES_SIGN_EXTEND
-@item SHORT_IMMEDIATES_SIGN_EXTEND
+You may return a non-@code{UNKNOWN} value even if for some hard registers
+the sign extension is not performed, if for the @code{REGNO_REG_CLASS}
+of these hard registers @code{CANNOT_CHANGE_MODE_CLASS} returns nonzero
+when the @var{from} mode is @var{mem_mode} and the @var{to} mode is any
+integral mode larger than this but not larger than @code{word_mode}.
+
+You must return @code{UNKNOWN} if for some hard registers that allow this
+mode, @code{CANNOT_CHANGE_MODE_CLASS} says that they cannot change to
+@code{word_mode}, but that they can change to another integral mode that
+is larger then @var{mem_mode} but still smaller than @code{word_mode}.
+@end defmac
+
+@defmac SHORT_IMMEDIATES_SIGN_EXTEND
Define this macro if loading short immediate values into registers sign
extends.
+@end defmac
-@findex FIXUNS_TRUNC_LIKE_FIX_TRUNC
-@item FIXUNS_TRUNC_LIKE_FIX_TRUNC
+@defmac FIXUNS_TRUNC_LIKE_FIX_TRUNC
Define this macro if the same instructions that convert a floating
point number to a signed fixed point number also convert validly to an
unsigned one.
+@end defmac
+
+@deftypefn {Target Hook} int TARGET_MIN_DIVISIONS_FOR_RECIP_MUL (enum machine_mode @var{mode})
+When @option{-ffast-math} is in effect, GCC tries to optimize
+divisions by the same divisor, by turning them into multiplications by
+the reciprocal. This target hook specifies the minimum number of divisions
+that should be there for GCC to perform the optimization for a variable
+of mode @var{mode}. The default implementation returns 3 if the machine
+has an instruction for the division, and 2 if it does not.
+@end deftypefn
-@findex MOVE_MAX
-@item MOVE_MAX
+@defmac MOVE_MAX
The maximum number of bytes that a single instruction can move quickly
between memory and registers or between two memory locations.
+@end defmac
-@findex MAX_MOVE_MAX
-@item MAX_MOVE_MAX
+@defmac MAX_MOVE_MAX
The maximum number of bytes that a single instruction can move quickly
between memory and registers or between two memory locations. If this
is undefined, the default is @code{MOVE_MAX}. Otherwise, it is the
constant value that is the largest value that @code{MOVE_MAX} can have
at run-time.
+@end defmac
-@findex SHIFT_COUNT_TRUNCATED
-@item SHIFT_COUNT_TRUNCATED
+@defmac SHIFT_COUNT_TRUNCATED
A C expression that is nonzero if on this machine the number of bits
actually used for the count of a shift operation is equal to the number
of bits needed to represent the size of the object being shifted. When
the implied truncation of the shift instructions.
You need not define this macro if it would always have the value of zero.
+@end defmac
+
+@anchor{TARGET_SHIFT_TRUNCATION_MASK}
+@deftypefn {Target Hook} int TARGET_SHIFT_TRUNCATION_MASK (enum machine_mode @var{mode})
+This function describes how the standard shift patterns for @var{mode}
+deal with shifts by negative amounts or by more than the width of the mode.
+@xref{shift patterns}.
+
+On many machines, the shift patterns will apply a mask @var{m} to the
+shift count, meaning that a fixed-width shift of @var{x} by @var{y} is
+equivalent to an arbitrary-width shift of @var{x} by @var{y & m}. If
+this is true for mode @var{mode}, the function should return @var{m},
+otherwise it should return 0. A return value of 0 indicates that no
+particular behavior is guaranteed.
+
+Note that, unlike @code{SHIFT_COUNT_TRUNCATED}, this function does
+@emph{not} apply to general shift rtxes; it applies only to instructions
+that are generated by the named shift patterns.
+
+The default implementation of this function returns
+@code{GET_MODE_BITSIZE (@var{mode}) - 1} if @code{SHIFT_COUNT_TRUNCATED}
+and 0 otherwise. This definition is always safe, but if
+@code{SHIFT_COUNT_TRUNCATED} is false, and some shift patterns
+nevertheless truncate the shift count, you may get better code
+by overriding it.
+@end deftypefn
-@findex TRULY_NOOP_TRUNCATION
-@item TRULY_NOOP_TRUNCATION (@var{outprec}, @var{inprec})
+@defmac TRULY_NOOP_TRUNCATION (@var{outprec}, @var{inprec})
A C expression which is nonzero if on this machine it is safe to
``convert'' an integer of @var{inprec} bits to one of @var{outprec}
bits (where @var{outprec} is smaller than @var{inprec}) by merely
modes for which @code{MODES_TIEABLE_P} is 0, suboptimal code can result.
If this is the case, making @code{TRULY_NOOP_TRUNCATION} return 0 in
such cases may improve things.
+@end defmac
+
+@deftypefn {Target Hook} int TARGET_MODE_REP_EXTENDED (enum machine_mode @var{mode}, enum machine_mode @var{rep_mode})
+The representation of an integral mode can be such that the values
+are always extended to a wider integral mode. Return
+@code{SIGN_EXTEND} if values of @var{mode} are represented in
+sign-extended form to @var{rep_mode}. Return @code{UNKNOWN}
+otherwise. (Currently, none of the targets use zero-extended
+representation this way so unlike @code{LOAD_EXTEND_OP},
+@code{TARGET_MODE_REP_EXTENDED} is expected to return either
+@code{SIGN_EXTEND} or @code{UNKNOWN}. Also no target extends
+@var{mode} to @var{mode_rep} so that @var{mode_rep} is not the next
+widest integral mode and currently we take advantage of this fact.)
+
+Similarly to @code{LOAD_EXTEND_OP} you may return a non-@code{UNKNOWN}
+value even if the extension is not performed on certain hard registers
+as long as for the @code{REGNO_REG_CLASS} of these hard registers
+@code{CANNOT_CHANGE_MODE_CLASS} returns nonzero.
+
+Note that @code{TARGET_MODE_REP_EXTENDED} and @code{LOAD_EXTEND_OP}
+describe two related properties. If you define
+@code{TARGET_MODE_REP_EXTENDED (mode, word_mode)} you probably also want
+to define @code{LOAD_EXTEND_OP (mode)} to return the same type of
+extension.
+
+In order to enforce the representation of @code{mode},
+@code{TRULY_NOOP_TRUNCATION} should return false when truncating to
+@code{mode}.
+@end deftypefn
-@findex STORE_FLAG_VALUE
-@item STORE_FLAG_VALUE
+@defmac STORE_FLAG_VALUE
A C expression describing the value returned by a comparison operator
with an integral mode and stored by a store-flag instruction
(@samp{s@var{cond}}) when the condition is true. This description must
@file{rs6000.md} for some examples. The GNU Superoptizer can be used to
find such instruction sequences on other machines.
-You need not define @code{STORE_FLAG_VALUE} if the machine has no store-flag
-instructions.
+If this macro is not defined, the default value, 1, is used. You need
+not define @code{STORE_FLAG_VALUE} if the machine has no store-flag
+instructions, or if the value generated by these instructions is 1.
+@end defmac
-@findex FLOAT_STORE_FLAG_VALUE
-@item FLOAT_STORE_FLAG_VALUE (@var{mode})
+@defmac FLOAT_STORE_FLAG_VALUE (@var{mode})
A C expression that gives a nonzero @code{REAL_VALUE_TYPE} value that is
returned when comparison operators with floating-point results are true.
-Define this macro on machine that have comparison operations that return
+Define this macro on machines that have comparison operations that return
floating-point values. If there are no such operations, do not define
this macro.
-
-@findex Pmode
-@item Pmode
+@end defmac
+
+@defmac VECTOR_STORE_FLAG_VALUE (@var{mode})
+A C expression that gives a rtx representing the nonzero true element
+for vector comparisons. The returned rtx should be valid for the inner
+mode of @var{mode} which is guaranteed to be a vector mode. Define
+this macro on machines that have vector comparison operations that
+return a vector result. If there are no such operations, do not define
+this macro. Typically, this macro is defined as @code{const1_rtx} or
+@code{constm1_rtx}. This macro may return @code{NULL_RTX} to prevent
+the compiler optimizing such vector comparison operations for the
+given mode.
+@end defmac
+
+@defmac CLZ_DEFINED_VALUE_AT_ZERO (@var{mode}, @var{value})
+@defmacx CTZ_DEFINED_VALUE_AT_ZERO (@var{mode}, @var{value})
+A C expression that indicates whether the architecture defines a value
+for @code{clz} or @code{ctz} with a zero operand.
+A result of @code{0} indicates the value is undefined.
+If the value is defined for only the RTL expression, the macro should
+evaluate to @code{1}; if the value applies also to the corresponding optab
+entry (which is normally the case if it expands directly into
+the corresponding RTL), then the macro should evaluate to @code{2}.
+In the cases where the value is defined, @var{value} should be set to
+this value.
+
+If this macro is not defined, the value of @code{clz} or
+@code{ctz} at zero is assumed to be undefined.
+
+This macro must be defined if the target's expansion for @code{ffs}
+relies on a particular value to get correct results. Otherwise it
+is not necessary, though it may be used to optimize some corner cases, and
+to provide a default expansion for the @code{ffs} optab.
+
+Note that regardless of this macro the ``definedness'' of @code{clz}
+and @code{ctz} at zero do @emph{not} extend to the builtin functions
+visible to the user. Thus one may be free to adjust the value at will
+to match the target expansion of these operations without fear of
+breaking the API@.
+@end defmac
+
+@defmac Pmode
An alias for the machine mode for pointers. On most machines, define
this to be the integer mode corresponding to the width of a hardware
pointer; @code{SImode} on 32-bit machine or @code{DImode} on 64-bit machines.
@code{POINTER_SIZE}. If it is not equal, you must define the macro
@code{POINTERS_EXTEND_UNSIGNED} to specify how pointers are extended
to @code{Pmode}.
+@end defmac
-@findex FUNCTION_MODE
-@item FUNCTION_MODE
+@defmac FUNCTION_MODE
An alias for the machine mode used for memory references to functions
-being called, in @code{call} RTL expressions. On most machines this
-should be @code{QImode}.
-
-@findex INTEGRATE_THRESHOLD
-@item INTEGRATE_THRESHOLD (@var{decl})
-A C expression for the maximum number of instructions above which the
-function @var{decl} should not be inlined. @var{decl} is a
-@code{FUNCTION_DECL} node.
-
-The default definition of this macro is 64 plus 8 times the number of
-arguments that the function accepts. Some people think a larger
-threshold should be used on RISC machines.
-
-@findex STDC_0_IN_SYSTEM_HEADERS
-@item STDC_0_IN_SYSTEM_HEADERS
+being called, in @code{call} RTL expressions. On most CISC machines,
+where an instruction can begin at any byte address, this should be
+@code{QImode}. On most RISC machines, where all instructions have fixed
+size and alignment, this should be a mode with the same size and alignment
+as the machine instruction words - typically @code{SImode} or @code{HImode}.
+@end defmac
+
+@defmac STDC_0_IN_SYSTEM_HEADERS
In normal operation, the preprocessor expands @code{__STDC__} to the
constant 1, to signify that GCC conforms to ISO Standard C@. On some
hosts, like Solaris, the system compiler uses a different convention,
Defining @code{STDC_0_IN_SYSTEM_HEADERS} makes GNU CPP follows the host
convention when processing system header files, but when processing user
files @code{__STDC__} will always expand to 1.
+@end defmac
-@findex SCCS_DIRECTIVE
-@item SCCS_DIRECTIVE
-Define this if the preprocessor should ignore @code{#sccs} directives
-and print no error message.
-
-@findex NO_IMPLICIT_EXTERN_C
-@item NO_IMPLICIT_EXTERN_C
+@defmac NO_IMPLICIT_EXTERN_C
Define this macro if the system header files support C++ as well as C@.
This macro inhibits the usual method of using system header files in
C++, which is to pretend that the file's contents are enclosed in
@samp{extern "C" @{@dots{}@}}.
+@end defmac
-@findex HANDLE_PRAGMA
-@item HANDLE_PRAGMA (@var{getc}, @var{ungetc}, @var{name})
-This macro is no longer supported. You must use
-@code{REGISTER_TARGET_PRAGMAS} instead.
-
-@findex REGISTER_TARGET_PRAGMAS
@findex #pragma
@findex pragma
-@item REGISTER_TARGET_PRAGMAS (@var{pfile})
+@defmac REGISTER_TARGET_PRAGMAS ()
Define this macro if you want to implement any target-specific pragmas.
If defined, it is a C expression which makes a series of calls to
-@code{cpp_register_pragma} for each pragma, with @var{pfile} passed as
-the first argument to to these functions. The macro may also do any
+@code{c_register_pragma} or @code{c_register_pragma_with_expansion}
+for each pragma. The macro may also do any
setup required for the pragmas.
The primary reason to define this macro is to provide compatibility with
Preprocessor macros that appear on pragma lines are not expanded. All
@samp{#pragma} directives that do not match any registered pragma are
silently ignored, unless the user specifies @option{-Wunknown-pragmas}.
+@end defmac
-@deftypefun void cpp_register_pragma (cpp_reader *@var{pfile}, const char *@var{space}, const char *@var{name}, void (*@var{callback}) (cpp_reader *))
+@deftypefun void c_register_pragma (const char *@var{space}, const char *@var{name}, void (*@var{callback}) (struct cpp_reader *))
+@deftypefunx void c_register_pragma_with_expansion (const char *@var{space}, const char *@var{name}, void (*@var{callback}) (struct cpp_reader *))
-Each call to @code{cpp_register_pragma} establishes one pragma. The
+Each call to @code{c_register_pragma} or
+@code{c_register_pragma_with_expansion} establishes one pragma. The
@var{callback} routine will be called when the preprocessor encounters a
pragma of the form
@code{NULL} to put the pragma in the global namespace. The callback
routine receives @var{pfile} as its first argument, which can be passed
on to cpplib's functions if necessary. You can lex tokens after the
-@var{name} by calling @code{c_lex}. Tokens that are not read by the
+@var{name} by calling @code{pragma_lex}. Tokens that are not read by the
callback will be silently ignored. The end of the line is indicated by
-a token of type @code{CPP_EOF}.
+a token of type @code{CPP_EOF}. Macro expansion occurs on the
+arguments of pragmas registered with
+@code{c_register_pragma_with_expansion} but not on the arguments of
+pragmas registered with @code{c_register_pragma}.
-For an example use of this routine, see @file{c4x.h} and the callback
-routines defined in @file{c4x-c.c}.
-
-Note that the use of @code{c_lex} is specific to the C and C++
+Note that the use of @code{pragma_lex} is specific to the C and C++
compilers. It will not work in the Java or Fortran compilers, or any
-other language compilers for that matter. Thus if @code{c_lex} is going
+other language compilers for that matter. Thus if @code{pragma_lex} is going
to be called from target-specific code, it must only be done so when
building the C and C++ compilers. This can be done by defining the
variables @code{c_target_objs} and @code{cxx_target_objs} in the
target entry in the @file{config.gcc} file. These variables should name
the target-specific, language-specific object file which contains the
-code that uses @code{c_lex}. Note it will also be necessary to add a
+code that uses @code{pragma_lex}. Note it will also be necessary to add a
rule to the makefile fragment pointed to by @code{tmake_file} that shows
how to build this object file.
@end deftypefun
-@findex HANDLE_SYSV_PRAGMA
@findex #pragma
@findex pragma
-@item HANDLE_SYSV_PRAGMA
+@defmac HANDLE_SYSV_PRAGMA
Define this macro (to a value of 1) if you want the System V style
pragmas @samp{#pragma pack(<n>)} and @samp{#pragma weak <name>
[=<value>]} to be supported by gcc.
@samp{__packed__} @code{__attribute__}s do. A pack value of zero resets
the behavior to the default.
+A subtlety for Microsoft Visual C/C++ style bit-field packing
+(e.g.@: -mms-bitfields) for targets that support it:
+When a bit-field is inserted into a packed record, the whole size
+of the underlying type is used by one or more same-size adjacent
+bit-fields (that is, if its long:3, 32 bits is used in the record,
+and any additional adjacent long bit-fields are packed into the same
+chunk of 32 bits. However, if the size changes, a new field of that
+size is allocated).
+
+If both MS bit-fields and @samp{__attribute__((packed))} are used,
+the latter will take precedence. If @samp{__attribute__((packed))} is
+used on a single field when MS bit-fields are in use, it will take
+precedence for that field, but the alignment of the rest of the structure
+may affect its placement.
+
The weak pragma only works if @code{SUPPORTS_WEAK} and
@code{ASM_WEAKEN_LABEL} are defined. If enabled it allows the creation
of specifically named weak labels, optionally with a value.
+@end defmac
-@findex HANDLE_PRAGMA_PACK_PUSH_POP
@findex #pragma
@findex pragma
-@item HANDLE_PRAGMA_PACK_PUSH_POP
+@defmac HANDLE_PRAGMA_PACK_PUSH_POP
Define this macro (to a value of 1) if you want to support the Win32
-style pragmas @samp{#pragma pack(push,@var{n})} and @samp{#pragma
-pack(pop)}. The @samp{pack(push,@var{n})} pragma specifies the maximum alignment
-(in bytes) of fields within a structure, in much the same way as the
-@samp{__aligned__} and @samp{__packed__} @code{__attribute__}s do. A
+style pragmas @samp{#pragma pack(push[,@var{n}])} and @samp{#pragma
+pack(pop)}. The @samp{pack(push,[@var{n}])} pragma specifies the maximum
+alignment (in bytes) of fields within a structure, in much the same way as
+the @samp{__aligned__} and @samp{__packed__} @code{__attribute__}s do. A
pack value of zero resets the behavior to the default. Successive
invocations of this pragma cause the previous values to be stacked, so
that invocations of @samp{#pragma pack(pop)} will return to the previous
value.
-
-@findex DOLLARS_IN_IDENTIFIERS
-@item DOLLARS_IN_IDENTIFIERS
-Define this macro to control use of the character @samp{$} in identifier
-names. 0 means @samp{$} is not allowed by default; 1 means it is allowed.
-1 is the default; there is no need to define this macro in that case.
-This macro controls the compiler proper; it does not affect the preprocessor.
-
-@findex NO_DOLLAR_IN_LABEL
-@item NO_DOLLAR_IN_LABEL
+@end defmac
+
+@defmac HANDLE_PRAGMA_PACK_WITH_EXPANSION
+Define this macro, as well as
+@code{HANDLE_SYSV_PRAGMA}, if macros should be expanded in the
+arguments of @samp{#pragma pack}.
+@end defmac
+
+@defmac TARGET_DEFAULT_PACK_STRUCT
+If your target requires a structure packing default other than 0 (meaning
+the machine default), define this macro to the necessary value (in bytes).
+This must be a value that would also be valid to use with
+@samp{#pragma pack()} (that is, a small power of two).
+@end defmac
+
+@defmac DOLLARS_IN_IDENTIFIERS
+Define this macro to control use of the character @samp{$} in
+identifier names for the C family of languages. 0 means @samp{$} is
+not allowed by default; 1 means it is allowed. 1 is the default;
+there is no need to define this macro in that case.
+@end defmac
+
+@defmac NO_DOLLAR_IN_LABEL
Define this macro if the assembler does not accept the character
@samp{$} in label names. By default constructors and destructors in
G++ have @samp{$} in the identifiers. If this macro is defined,
@samp{.} is used instead.
+@end defmac
-@findex NO_DOT_IN_LABEL
-@item NO_DOT_IN_LABEL
+@defmac NO_DOT_IN_LABEL
Define this macro if the assembler does not accept the character
@samp{.} in label names. By default constructors and destructors in G++
have names that use @samp{.}. If this macro is defined, these names
are rewritten to avoid @samp{.}.
+@end defmac
-@findex DEFAULT_MAIN_RETURN
-@item DEFAULT_MAIN_RETURN
-Define this macro if the target system expects every program's @code{main}
-function to return a standard ``success'' value by default (if no other
-value is explicitly returned).
-
-The definition should be a C statement (sans semicolon) to generate the
-appropriate rtl instructions. It is used only when compiling the end of
-@code{main}.
-
-@item NEED_ATEXIT
-@findex NEED_ATEXIT
-Define this if the target system lacks the function @code{atexit}
-from the ISO C standard. If this macro is defined, a default definition
-will be provided to support C++. If @code{ON_EXIT} is not defined,
-a default @code{exit} function will also be provided.
-
-@item ON_EXIT
-@findex ON_EXIT
-Define this macro if the target has another way to implement atexit
-functionality without replacing @code{exit}. For instance, SunOS 4 has
-a similar @code{on_exit} library function.
-
-The definition should be a functional macro which can be used just like
-the @code{atexit} function.
-
-@item EXIT_BODY
-@findex EXIT_BODY
-Define this if your @code{exit} function needs to do something
-besides calling an external function @code{_cleanup} before
-terminating with @code{_exit}. The @code{EXIT_BODY} macro is
-only needed if @code{NEED_ATEXIT} is defined and @code{ON_EXIT} is not
-defined.
-
-@findex INSN_SETS_ARE_DELAYED
-@item INSN_SETS_ARE_DELAYED (@var{insn})
+@defmac INSN_SETS_ARE_DELAYED (@var{insn})
Define this macro as a C expression that is nonzero if it is safe for the
delay slot scheduler to place instructions in the delay slot of @var{insn},
even if they appear to use a resource set or clobbered in @var{insn}.
you should define this macro.
You need not define this macro if it would always return zero.
+@end defmac
-@findex INSN_REFERENCES_ARE_DELAYED
-@item INSN_REFERENCES_ARE_DELAYED (@var{insn})
+@defmac INSN_REFERENCES_ARE_DELAYED (@var{insn})
Define this macro as a C expression that is nonzero if it is safe for the
delay slot scheduler to place instructions in the delay slot of @var{insn},
even if they appear to set or clobber a resource referenced in @var{insn}.
slot of @var{insn}.
You need not define this macro if it would always return zero.
+@end defmac
+
+@defmac MULTIPLE_SYMBOL_SPACES
+Define this macro as a C expression that is nonzero if, in some cases,
+global symbols from one translation unit may not be bound to undefined
+symbols in another translation unit without user intervention. For
+instance, under Microsoft Windows symbols must be explicitly imported
+from shared libraries (DLLs).
+
+You need not define this macro if it would always evaluate to zero.
+@end defmac
+
+@deftypefn {Target Hook} tree TARGET_MD_ASM_CLOBBERS (tree @var{outputs}, tree @var{inputs}, tree @var{clobbers})
+This target hook should add to @var{clobbers} @code{STRING_CST} trees for
+any hard regs the port wishes to automatically clobber for an asm.
+It should return the result of the last @code{tree_cons} used to add a
+clobber. The @var{outputs}, @var{inputs} and @var{clobber} lists are the
+corresponding parameters to the asm and may be inspected to avoid
+clobbering a register that is an input or output of the asm. You can use
+@code{tree_overlaps_hard_reg_set}, declared in @file{tree.h}, to test
+for overlap with regards to asm-declared registers.
+@end deftypefn
-@findex MACHINE_DEPENDENT_REORG
-@item MACHINE_DEPENDENT_REORG (@var{insn})
-In rare cases, correct code generation requires extra machine
-dependent processing between the second jump optimization pass and
-delayed branch scheduling. On those machines, define this macro as a C
-statement to act on the code starting at @var{insn}.
-
-@findex MULTIPLE_SYMBOL_SPACES
-@item MULTIPLE_SYMBOL_SPACES
-Define this macro if in some cases global symbols from one translation
-unit may not be bound to undefined symbols in another translation unit
-without user intervention. For instance, under Microsoft Windows
-symbols must be explicitly imported from shared libraries (DLLs).
-
-@findex MD_ASM_CLOBBERS
-@item MD_ASM_CLOBBERS (@var{clobbers})
-A C statement that adds to @var{clobbers} @code{STRING_CST} trees for
-any hard regs the port wishes to automatically clobber for all asms.
-
-@findex MAX_INTEGER_COMPUTATION_MODE
-@item MAX_INTEGER_COMPUTATION_MODE
-Define this to the largest integer machine mode which can be used for
-operations other than load, store and copy operations.
-
-You need only define this macro if the target holds values larger than
-@code{word_mode} in general purpose registers. Most targets should not define
-this macro.
-
-@findex MATH_LIBRARY
-@item MATH_LIBRARY
+@defmac MATH_LIBRARY
Define this macro as a C string constant for the linker argument to link
in the system math library, or @samp{""} if the target does not have a
separate math library.
You need only define this macro if the default of @samp{"-lm"} is wrong.
+@end defmac
-@findex LIBRARY_PATH_ENV
-@item LIBRARY_PATH_ENV
+@defmac LIBRARY_PATH_ENV
Define this macro as a C string constant for the environment variable that
specifies where the linker should look for libraries.
You need only define this macro if the default of @samp{"LIBRARY_PATH"}
is wrong.
+@end defmac
-@findex TARGET_HAS_F_SETLKW
-@item TARGET_HAS_F_SETLKW
-Define this macro if the target supports file locking with fcntl / F_SETLKW@.
-Note that this functionality is part of POSIX@.
-Defining @code{TARGET_HAS_F_SETLKW} will enable the test coverage code
+@defmac TARGET_POSIX_IO
+Define this macro if the target supports the following POSIX@ file
+functions, access, mkdir and file locking with fcntl / F_SETLKW@.
+Defining @code{TARGET_POSIX_IO} will enable the test coverage code
to use file locking when exiting a program, which avoids race conditions
-if the program has forked.
+if the program has forked. It will also create directories at run-time
+for cross-profiling.
+@end defmac
-@findex MAX_CONDITIONAL_EXECUTE
-@item MAX_CONDITIONAL_EXECUTE
+@defmac MAX_CONDITIONAL_EXECUTE
A C expression for the maximum number of instructions to execute via
conditional execution instructions instead of a branch. A value of
@code{BRANCH_COST}+1 is the default if the machine does not use cc0, and
1 if it does use cc0.
-
-@findex IFCVT_MODIFY_TESTS
-@item IFCVT_MODIFY_TESTS
-A C expression to modify the tests in @code{TRUE_EXPR}, and
-@code{FALSE_EXPR} for use in converting insns in @code{TEST_BB},
-@code{THEN_BB}, @code{ELSE_BB}, and @code{JOIN_BB} basic blocks to
-conditional execution. Set either @code{TRUE_EXPR} or @code{FALSE_EXPR}
-to a null pointer if the tests cannot be converted.
-
-@findex IFCVT_MODIFY_INSN
-@item IFCVT_MODIFY_INSN
-A C expression to modify the @code{PATTERN} of an @code{INSN} that is to
-be converted to conditional execution format.
-
-@findex IFCVT_MODIFY_FINAL
-@item IFCVT_MODIFY_FINAL
+@end defmac
+
+@defmac IFCVT_MODIFY_TESTS (@var{ce_info}, @var{true_expr}, @var{false_expr})
+Used if the target needs to perform machine-dependent modifications on the
+conditionals used for turning basic blocks into conditionally executed code.
+@var{ce_info} points to a data structure, @code{struct ce_if_block}, which
+contains information about the currently processed blocks. @var{true_expr}
+and @var{false_expr} are the tests that are used for converting the
+then-block and the else-block, respectively. Set either @var{true_expr} or
+@var{false_expr} to a null pointer if the tests cannot be converted.
+@end defmac
+
+@defmac IFCVT_MODIFY_MULTIPLE_TESTS (@var{ce_info}, @var{bb}, @var{true_expr}, @var{false_expr})
+Like @code{IFCVT_MODIFY_TESTS}, but used when converting more complicated
+if-statements into conditions combined by @code{and} and @code{or} operations.
+@var{bb} contains the basic block that contains the test that is currently
+being processed and about to be turned into a condition.
+@end defmac
+
+@defmac IFCVT_MODIFY_INSN (@var{ce_info}, @var{pattern}, @var{insn})
+A C expression to modify the @var{PATTERN} of an @var{INSN} that is to
+be converted to conditional execution format. @var{ce_info} points to
+a data structure, @code{struct ce_if_block}, which contains information
+about the currently processed blocks.
+@end defmac
+
+@defmac IFCVT_MODIFY_FINAL (@var{ce_info})
A C expression to perform any final machine dependent modifications in
-converting code to conditional execution in the basic blocks
-@code{TEST_BB}, @code{THEN_BB}, @code{ELSE_BB}, and @code{JOIN_BB}.
+converting code to conditional execution. The involved basic blocks
+can be found in the @code{struct ce_if_block} structure that is pointed
+to by @var{ce_info}.
+@end defmac
-@findex IFCVT_MODIFY_CANCEL
-@item IFCVT_MODIFY_CANCEL
+@defmac IFCVT_MODIFY_CANCEL (@var{ce_info})
A C expression to cancel any machine dependent modifications in
-converting code to conditional execution in the basic blocks
-@code{TEST_BB}, @code{THEN_BB}, @code{ELSE_BB}, and @code{JOIN_BB}.
-@end table
+converting code to conditional execution. The involved basic blocks
+can be found in the @code{struct ce_if_block} structure that is pointed
+to by @var{ce_info}.
+@end defmac
+
+@defmac IFCVT_INIT_EXTRA_FIELDS (@var{ce_info})
+A C expression to initialize any extra fields in a @code{struct ce_if_block}
+structure, which are defined by the @code{IFCVT_EXTRA_FIELDS} macro.
+@end defmac
+
+@defmac IFCVT_EXTRA_FIELDS
+If defined, it should expand to a set of field declarations that will be
+added to the @code{struct ce_if_block} structure. These should be initialized
+by the @code{IFCVT_INIT_EXTRA_FIELDS} macro.
+@end defmac
+
+@deftypefn {Target Hook} void TARGET_MACHINE_DEPENDENT_REORG ()
+If non-null, this hook performs a target-specific pass over the
+instruction stream. The compiler will run it at all optimization levels,
+just before the point at which it normally does delayed-branch scheduling.
+
+The exact purpose of the hook varies from target to target. Some use
+it to do transformations that are necessary for correctness, such as
+laying out in-function constant pools or avoiding hardware hazards.
+Others use it as an opportunity to do some machine-dependent optimizations.
+
+You need not implement the hook if it has nothing to do. The default
+definition is null.
+@end deftypefn
@deftypefn {Target Hook} void TARGET_INIT_BUILTINS ()
Define this hook if you have any machine-specific built-in functions
they have no equivalent in the source language (for example, SIMD vector
instructions or prefetch instructions).
-To create a built-in function, call the function @code{builtin_function}
+To create a built-in function, call the function
+@code{lang_hooks.builtin_function}
which is defined by the language front end. You can use any type nodes set
up by @code{build_common_tree_nodes} and @code{build_common_tree_nodes_2};
only language front ends that use those two functions will call
built-in function.
@end deftypefn
-@table @code
-@findex MD_CAN_REDIRECT_BRANCH
-@item MD_CAN_REDIRECT_BRANCH(@var{branch1}, @var{branch2})
+@deftypefn {Target Hook} tree TARGET_RESOLVE_OVERLOADED_BUILTIN (tree @var{fndecl}, tree @var{arglist})
+
+Select a replacement for a machine specific built-in function that
+was set up by @samp{TARGET_INIT_BUILTINS}. This is done
+@emph{before} regular type checking, and so allows the target to
+implement a crude form of function overloading. @var{fndecl} is the
+declaration of the built-in function. @var{arglist} is the list of
+arguments passed to the built-in function. The result is a
+complete expression that implements the operation, usually
+another @code{CALL_EXPR}.
+@end deftypefn
+
+@deftypefn {Target Hook} tree TARGET_FOLD_BUILTIN (tree @var{fndecl}, tree @var{arglist}, bool @var{ignore})
+
+Fold a call to a machine specific built-in function that was set up by
+@samp{TARGET_INIT_BUILTINS}. @var{fndecl} is the declaration of the
+built-in function. @var{arglist} is the list of arguments passed to
+the built-in function. The result is another tree containing a
+simplified expression for the call's result. If @var{ignore} is true
+the value will be ignored.
+@end deftypefn
+
+@deftypefn {Target Hook} const char * TARGET_INVALID_WITHIN_DOLOOP (rtx @var{insn})
+
+Take an instruction in @var{insn} and return NULL if it is valid within a
+low-overhead loop, otherwise return a string why doloop could not be applied.
+
+Many targets use special registers for low-overhead looping. For any
+instruction that clobbers these this function should return a string indicating
+the reason why the doloop could not be applied.
+By default, the RTL loop optimizer does not use a present doloop pattern for
+loops containing function calls or branch on table instructions.
+@end deftypefn
+
+@defmac MD_CAN_REDIRECT_BRANCH (@var{branch1}, @var{branch2})
Take a branch insn in @var{branch1} and another in @var{branch2}.
Return true if redirecting @var{branch1} to the destination of
On some targets, branches may have a limited range. Optimizing the
filling of delay slots can result in branches being redirected, and this
may in turn cause a branch offset to overflow.
+@end defmac
+
+@deftypefn {Target Hook} bool TARGET_COMMUTATIVE_P (rtx @var{x}, @var{outer_code})
+This target hook returns @code{true} if @var{x} is considered to be commutative.
+Usually, this is just COMMUTATIVE_P (@var{x}), but the HP PA doesn't consider
+PLUS to be commutative inside a MEM@. @var{outer_code} is the rtx code
+of the enclosing rtl, if known, otherwise it is UNKNOWN.
+@end deftypefn
-@findex ALLOCATE_INITIAL_VALUE
-@item ALLOCATE_INITIAL_VALUE(@var{hard_reg})
+@deftypefn {Target Hook} rtx TARGET_ALLOCATE_INITIAL_VALUE (rtx @var{hard_reg})
When the initial value of a hard register has been copied in a pseudo
register, it is often not necessary to actually allocate another register
to this pseudo register, because the original hard register or a stack slot
-it has been saved into can be used. @code{ALLOCATE_INITIAL_VALUE}, if
-defined, is called at the start of register allocation once for each
-hard register that had its initial value copied by using
+it has been saved into can be used. @code{TARGET_ALLOCATE_INITIAL_VALUE}
+is called at the start of register allocation once for each hard register
+that had its initial value copied by using
@code{get_func_hard_reg_initial_val} or @code{get_hard_reg_initial_val}.
Possible values are @code{NULL_RTX}, if you don't want
to do any special allocation, a @code{REG} rtx---that would typically be
@code{MEM}.
If you are returning a @code{MEM}, this is only a hint for the allocator;
it might decide to use another register anyways.
-You may use @code{current_function_leaf_function} in the definition of the
-macro, functions that use @code{REG_N_SETS}, to determine if the hard
+You may use @code{current_function_leaf_function} in the hook, functions
+that use @code{REG_N_SETS}, to determine if the hard
register in question will not be clobbered.
+The default value of this hook is @code{NULL}, which disables any special
+allocation.
+@end deftypefn
+
+@deftypefn {Target Hook} int TARGET_UNSPEC_MAY_TRAP_P (const_rtx @var{x}, unsigned @var{flags})
+This target hook returns nonzero if @var{x}, an @code{unspec} or
+@code{unspec_volatile} operation, might cause a trap. Targets can use
+this hook to enhance precision of analysis for @code{unspec} and
+@code{unspec_volatile} operations. You may call @code{may_trap_p_1}
+to analyze inner elements of @var{x} in which case @var{flags} should be
+passed along.
+@end deftypefn
+
+@deftypefn {Target Hook} void TARGET_SET_CURRENT_FUNCTION (tree @var{decl})
+The compiler invokes this hook whenever it changes its current function
+context (@code{cfun}). You can define this function if
+the back end needs to perform any initialization or reset actions on a
+per-function basis. For example, it may be used to implement function
+attributes that affect register usage or code generation patterns.
+The argument @var{decl} is the declaration for the new function context,
+and may be null to indicate that the compiler has left a function context
+and is returning to processing at the top level.
+The default hook function does nothing.
+
+GCC sets @code{cfun} to a dummy function context during initialization of
+some parts of the back end. The hook function is not invoked in this
+situation; you need not worry about the hook being invoked recursively,
+or when the back end is in a partially-initialized state.
+@end deftypefn
-@findex TARGET_OBJECT_SUFFIX
-@item TARGET_OBJECT_SUFFIX
+@defmac TARGET_OBJECT_SUFFIX
Define this macro to be a C string representing the suffix for object
files on your target machine. If you do not define this macro, GCC will
use @samp{.o} as the suffix for object files.
+@end defmac
-@findex TARGET_EXECUTABLE_SUFFIX
-@item TARGET_EXECUTABLE_SUFFIX
+@defmac TARGET_EXECUTABLE_SUFFIX
Define this macro to be a C string representing the suffix to be
automatically added to executable files on your target machine. If you
do not define this macro, GCC will use the null string as the suffix for
executable files.
+@end defmac
-@findex COLLECT_EXPORT_LIST
-@item COLLECT_EXPORT_LIST
+@defmac COLLECT_EXPORT_LIST
If defined, @code{collect2} will scan the individual object files
specified on its command line and create an export list for the linker.
Define this macro for systems like AIX, where the linker discards
object files that are not referenced from @code{main} and uses export
lists.
+@end defmac
-@end table
+@defmac MODIFY_JNI_METHOD_CALL (@var{mdecl})
+Define this macro to a C expression representing a variant of the
+method call @var{mdecl}, if Java Native Interface (JNI) methods
+must be invoked differently from other methods on your target.
+For example, on 32-bit Microsoft Windows, JNI methods must be invoked using
+the @code{stdcall} calling convention and this macro is then
+defined as this expression:
+
+@smallexample
+build_type_attribute_variant (@var{mdecl},
+ build_tree_list
+ (get_identifier ("stdcall"),
+ NULL))
+@end smallexample
+@end defmac
@deftypefn {Target Hook} bool TARGET_CANNOT_MODIFY_JUMPS_P (void)
This target hook returns @code{true} past the point in which new jump
@}
@end smallexample
@end deftypefn
+
+@deftypefn {Target Hook} int TARGET_BRANCH_TARGET_REGISTER_CLASS (void)
+This target hook returns a register class for which branch target register
+optimizations should be applied. All registers in this class should be
+usable interchangeably. After reload, registers in this class will be
+re-allocated and loads will be hoisted out of loops and be subjected
+to inter-block scheduling.
+@end deftypefn
+
+@deftypefn {Target Hook} bool TARGET_BRANCH_TARGET_REGISTER_CALLEE_SAVED (bool @var{after_prologue_epilogue_gen})
+Branch target register optimization will by default exclude callee-saved
+registers
+that are not already live during the current function; if this target hook
+returns true, they will be included. The target code must than make sure
+that all target registers in the class returned by
+@samp{TARGET_BRANCH_TARGET_REGISTER_CLASS} that might need saving are
+saved. @var{after_prologue_epilogue_gen} indicates if prologues and
+epilogues have already been generated. Note, even if you only return
+true when @var{after_prologue_epilogue_gen} is false, you still are likely
+to have to make special provisions in @code{INITIAL_ELIMINATION_OFFSET}
+to reserve space for caller-saved target registers.
+@end deftypefn
+
+@defmac POWI_MAX_MULTS
+If defined, this macro is interpreted as a signed integer C expression
+that specifies the maximum number of floating point multiplications
+that should be emitted when expanding exponentiation by an integer
+constant inline. When this value is defined, exponentiation requiring
+more than this number of multiplications is implemented by calling the
+system library's @code{pow}, @code{powf} or @code{powl} routines.
+The default value places no upper bound on the multiplication count.
+@end defmac
+
+@deftypefn Macro void TARGET_EXTRA_INCLUDES (const char *@var{sysroot}, const char *@var{iprefix}, int @var{stdinc})
+This target hook should register any extra include files for the
+target. The parameter @var{stdinc} indicates if normal include files
+are present. The parameter @var{sysroot} is the system root directory.
+The parameter @var{iprefix} is the prefix for the gcc directory.
+@end deftypefn
+
+@deftypefn Macro void TARGET_EXTRA_PRE_INCLUDES (const char *@var{sysroot}, const char *@var{iprefix}, int @var{stdinc})
+This target hook should register any extra include files for the
+target before any standard headers. The parameter @var{stdinc}
+indicates if normal include files are present. The parameter
+@var{sysroot} is the system root directory. The parameter
+@var{iprefix} is the prefix for the gcc directory.
+@end deftypefn
+
+@deftypefn Macro void TARGET_OPTF (char *@var{path})
+This target hook should register special include paths for the target.
+The parameter @var{path} is the include to register. On Darwin
+systems, this is used for Framework includes, which have semantics
+that are different from @option{-I}.
+@end deftypefn
+
+@deftypefn {Target Hook} bool TARGET_USE_LOCAL_THUNK_ALIAS_P (tree @var{fndecl})
+This target hook returns @code{true} if it is safe to use a local alias
+for a virtual function @var{fndecl} when constructing thunks,
+@code{false} otherwise. By default, the hook returns @code{true} for all
+functions, if a target supports aliases (i.e.@: defines
+@code{ASM_OUTPUT_DEF}), @code{false} otherwise,
+@end deftypefn
+
+@defmac TARGET_FORMAT_TYPES
+If defined, this macro is the name of a global variable containing
+target-specific format checking information for the @option{-Wformat}
+option. The default is to have no target-specific format checks.
+@end defmac
+
+@defmac TARGET_N_FORMAT_TYPES
+If defined, this macro is the number of entries in
+@code{TARGET_FORMAT_TYPES}.
+@end defmac
+
+@defmac TARGET_OVERRIDES_FORMAT_ATTRIBUTES
+If defined, this macro is the name of a global variable containing
+target-specific format overrides for the @option{-Wformat} option. The
+default is to have no target-specific format overrides. If defined,
+@code{TARGET_FORMAT_TYPES} must be defined, too.
+@end defmac
+
+@defmac TARGET_OVERRIDES_FORMAT_ATTRIBUTES_COUNT
+If defined, this macro specifies the number of entries in
+@code{TARGET_OVERRIDES_FORMAT_ATTRIBUTES}.
+@end defmac
+
+@defmac TARGET_OVERRIDES_FORMAT_INIT
+If defined, this macro specifies the optional initialization
+routine for target specific customizations of the system printf
+and scanf formatter settings.
+@end defmac
+
+@deftypefn {Target Hook} bool TARGET_RELAXED_ORDERING
+If set to @code{true}, means that the target's memory model does not
+guarantee that loads which do not depend on one another will access
+main memory in the order of the instruction stream; if ordering is
+important, an explicit memory barrier must be used. This is true of
+many recent processors which implement a policy of ``relaxed,''
+``weak,'' or ``release'' memory consistency, such as Alpha, PowerPC,
+and ia64. The default is @code{false}.
+@end deftypefn
+
+@deftypefn {Target Hook} const char *TARGET_INVALID_ARG_FOR_UNPROTOTYPED_FN (tree @var{typelist}, tree @var{funcdecl}, tree @var{val})
+If defined, this macro returns the diagnostic message when it is
+illegal to pass argument @var{val} to function @var{funcdecl}
+with prototype @var{typelist}.
+@end deftypefn
+
+@deftypefn {Target Hook} {const char *} TARGET_INVALID_CONVERSION (tree @var{fromtype}, tree @var{totype})
+If defined, this macro returns the diagnostic message when it is
+invalid to convert from @var{fromtype} to @var{totype}, or @code{NULL}
+if validity should be determined by the front end.
+@end deftypefn
+
+@deftypefn {Target Hook} {const char *} TARGET_INVALID_UNARY_OP (int @var{op}, tree @var{type})
+If defined, this macro returns the diagnostic message when it is
+invalid to apply operation @var{op} (where unary plus is denoted by
+@code{CONVERT_EXPR}) to an operand of type @var{type}, or @code{NULL}
+if validity should be determined by the front end.
+@end deftypefn
+
+@deftypefn {Target Hook} {const char *} TARGET_INVALID_BINARY_OP (int @var{op}, tree @var{type1}, tree @var{type2})
+If defined, this macro returns the diagnostic message when it is
+invalid to apply operation @var{op} to operands of types @var{type1}
+and @var{type2}, or @code{NULL} if validity should be determined by
+the front end.
+@end deftypefn
+
+@defmac TARGET_USE_JCR_SECTION
+This macro determines whether to use the JCR section to register Java
+classes. By default, TARGET_USE_JCR_SECTION is defined to 1 if both
+SUPPORTS_WEAK and TARGET_HAVE_NAMED_SECTIONS are true, else 0.
+@end defmac
+
+@defmac OBJC_JBLEN
+This macro determines the size of the objective C jump buffer for the
+NeXT runtime. By default, OBJC_JBLEN is defined to an innocuous value.
+@end defmac
+
+@defmac LIBGCC2_UNWIND_ATTRIBUTE
+Define this macro if any target-specific attributes need to be attached
+to the functions in @file{libgcc} that provide low-level support for
+call stack unwinding. It is used in declarations in @file{unwind-generic.h}
+and the associated definitions of those functions.
+@end defmac
+
+@deftypefn {Target Hook} void TARGET_UPDATE_STACK_BOUNDARY (void)
+Define this macro to update the current function stack boundary if
+necessary.
+@end deftypefn
+
+@deftypefn {Target Hook} rtx TARGET_GET_DRAP_RTX (void)
+Define this macro to an rtx for Dynamic Realign Argument Pointer if a
+different argument pointer register is needed to access the function's
+argument list when stack is aligned.
+@end deftypefn
+
+@deftypefn {Target Hook} {bool} TARGET_ALLOCATE_STACK_SLOTS_FOR_ARGS (void)
+When optimization is disabled, this hook indicates whether or not
+arguments should be allocated to stack slots. Normally, GCC allocates
+stacks slots for arguments when not optimizing in order to make
+debugging easier. However, when a function is declared with
+@code{__attribute__((naked))}, there is no stack frame, and the compiler
+cannot safely move arguments from the registers in which they are passed
+to the stack. Therefore, this hook should return true in general, but
+false for naked functions. The default implementation always returns true.
+@end deftypefn
projects / msp430-gcc.git / blobdiff