+++ /dev/null
-README for libffi-2.00
-
-libffi-2.00 has not been released yet! This is a development snapshot!
-
-libffi-1.20 was released on [SOME FUTURE DAY]. Check the libffi web
-page for updates: <URL:http://sourceware.cygnus.com/libffi/>.
-
-
-What is libffi?
-===============
-
-Compilers for high level languages generate code that follow certain
-conventions. These conventions are necessary, in part, for separate
-compilation to work. One such convention is the "calling
-convention". The "calling convention" is essentially a set of
-assumptions made by the compiler about where function arguments will
-be found on entry to a function. A "calling convention" also specifies
-where the return value for a function is found.
-
-Some programs may not know at the time of compilation what arguments
-are to be passed to a function. For instance, an interpreter may be
-told at run-time about the number and types of arguments used to call
-a given function. Libffi can be used in such programs to provide a
-bridge from the interpreter program to compiled code.
-
-The libffi library provides a portable, high level programming
-interface to various calling conventions. This allows a programmer to
-call any function specified by a call interface description at run
-time.
-
-Ffi stands for Foreign Function Interface. A foreign function
-interface is the popular name for the interface that allows code
-written in one language to call code written in another language. The
-libffi library really only provides the lowest, machine dependent
-layer of a fully featured foreign function interface. A layer must
-exist above libffi that handles type conversions for values passed
-between the two languages.
-
-
-Supported Platforms and Prerequisites
-=====================================
-
-Libffi has been ported to:
-
- SunOS 4.1.3 & Solaris 2.x (Sparc v8)
-
- Irix 5.3 & 6.2 (System V/o32 & n32)
-
- Intel x86 - Linux (System V ABI)
-
- Alpha - Linux and OSF/1
-
- m68k - Linux (System V ABI)
-
- PowerPC - Linux (System V ABI, Darwin, AIX)
-
- ARM - Linux (System V ABI)
-
-Libffi has been tested with the egcs 1.0.2 gcc compiler. Chances are
-that other versions will work. Libffi has also been built and tested
-with the SGI compiler tools.
-
-On PowerPC, the tests failed (see the note below).
-
-You must use GNU make to build libffi. SGI's make will not work.
-Sun's probably won't either.
-
-If you port libffi to another platform, please let me know! I assume
-that some will be easy (x86 NetBSD), and others will be more difficult
-(HP).
-
-
-Installing libffi
-=================
-
-[Note: before actually performing any of these installation steps,
- you may wish to read the "Platform Specific Notes" below.]
-
-First you must configure the distribution for your particular
-system. Go to the directory you wish to build libffi in and run the
-"configure" program found in the root directory of the libffi source
-distribution.
-
-You may want to tell configure where to install the libffi library and
-header files. To do that, use the --prefix configure switch. Libffi
-will install under /usr/local by default.
-
-If you want to enable extra run-time debugging checks use the the
---enable-debug configure switch. This is useful when your program dies
-mysteriously while using libffi.
-
-Another useful configure switch is --enable-purify-safety. Using this
-will add some extra code which will suppress certain warnings when you
-are using Purify with libffi. Only use this switch when using
-Purify, as it will slow down the library.
-
-Configure has many other options. Use "configure --help" to see them all.
-
-Once configure has finished, type "make". Note that you must be using
-GNU make. SGI's make will not work. Sun's probably won't either.
-You can ftp GNU make from prep.ai.mit.edu:/pub/gnu.
-
-To ensure that libffi is working as advertised, type "make test".
-
-To install the library and header files, type "make install".
-
-
-Using libffi
-============
-
- The Basics
- ----------
-
-Libffi assumes that you have a pointer to the function you wish to
-call and that you know the number and types of arguments to pass it,
-as well as the return type of the function.
-
-The first thing you must do is create an ffi_cif object that matches
-the signature of the function you wish to call. The cif in ffi_cif
-stands for Call InterFace. To prepare a call interface object, use the
-following function:
-
-ffi_status ffi_prep_cif(ffi_cif *cif, ffi_abi abi,
- unsigned int nargs,
- ffi_type *rtype, ffi_type **atypes);
-
- CIF is a pointer to the call interface object you wish
- to initialize.
-
- ABI is an enum that specifies the calling convention
- to use for the call. FFI_DEFAULT_ABI defaults
- to the system's native calling convention. Other
- ABI's may be used with care. They are system
- specific.
-
- NARGS is the number of arguments this function accepts.
- libffi does not yet support vararg functions.
-
- RTYPE is a pointer to an ffi_type structure that represents
- the return type of the function. Ffi_type objects
- describe the types of values. libffi provides
- ffi_type objects for many of the native C types:
- signed int, unsigned int, signed char, unsigned char,
- etc. There is also a pointer ffi_type object and
- a void ffi_type. Use &ffi_type_void for functions that
- don't return values.
-
- ATYPES is a vector of ffi_type pointers. ARGS must be NARGS long.
- If NARGS is 0, this is ignored.
-
-
-ffi_prep_cif will return a status code that you are responsible
-for checking. It will be one of the following:
-
- FFI_OK - All is good.
-
- FFI_BAD_TYPEDEF - One of the ffi_type objects that ffi_prep_cif
- came across is bad.
-
-
-Before making the call, the VALUES vector should be initialized
-with pointers to the appropriate argument values.
-
-To call the the function using the initialized ffi_cif, use the
-ffi_call function:
-
-void ffi_call(ffi_cif *cif, void *fn, void *rvalue, void **avalues);
-
- CIF is a pointer to the ffi_cif initialized specifically
- for this function.
-
- FN is a pointer to the function you want to call.
-
- RVALUE is a pointer to a chunk of memory that is to hold the
- result of the function call. Currently, it must be
- at least one word in size (except for the n32 version
- under Irix 6.x, which must be a pointer to an 8 byte
- aligned value (a long long). It must also be at least
- word aligned (depending on the return type, and the
- system's alignment requirements). If RTYPE is
- &ffi_type_void, this is ignored. If RVALUE is NULL,
- the return value is discarded.
-
- AVALUES is a vector of void* that point to the memory locations
- holding the argument values for a call.
- If NARGS is 0, this is ignored.
-
-
-If you are expecting a return value from FN it will have been stored
-at RVALUE.
-
-
-
- An Example
- ----------
-
-Here is a trivial example that calls puts() a few times.
-
- #include <stdio.h>
- #include <ffi.h>
-
- int main()
- {
- ffi_cif cif;
- ffi_type *args[1];
- void *values[1];
- char *s;
- int rc;
-
- /* Initialize the argument info vectors */
- args[0] = &ffi_type_uint;
- values[0] = &s;
-
- /* Initialize the cif */
- if (ffi_prep_cif(&cif, FFI_DEFAULT_ABI, 1,
- &ffi_type_uint, args) == FFI_OK)
- {
- s = "Hello World!";
- ffi_call(&cif, puts, &rc, values);
- /* rc now holds the result of the call to puts */
-
- /* values holds a pointer to the function's arg, so to
- call puts() again all we need to do is change the
- value of s */
- s = "This is cool!";
- ffi_call(&cif, puts, &rc, values);
- }
-
- return 0;
- }
-
-
-
- Aggregate Types
- ---------------
-
-Although libffi has no special support for unions or bit-fields, it is
-perfectly happy passing structures back and forth. You must first
-describe the structure to libffi by creating a new ffi_type object
-for it. Here is the definition of ffi_type:
-
- typedef struct _ffi_type
- {
- unsigned size;
- short alignment;
- short type;
- struct _ffi_type **elements;
- } ffi_type;
-
-All structures must have type set to FFI_TYPE_STRUCT. You may set
-size and alignment to 0. These will be calculated and reset to the
-appropriate values by ffi_prep_cif().
-
-elements is a NULL terminated array of pointers to ffi_type objects
-that describe the type of the structure elements. These may, in turn,
-be structure elements.
-
-The following example initializes a ffi_type object representing the
-tm struct from Linux's time.h:
-
- struct tm {
- int tm_sec;
- int tm_min;
- int tm_hour;
- int tm_mday;
- int tm_mon;
- int tm_year;
- int tm_wday;
- int tm_yday;
- int tm_isdst;
- /* Those are for future use. */
- long int __tm_gmtoff__;
- __const char *__tm_zone__;
- };
-
- {
- ffi_type tm_type;
- ffi_type *tm_type_elements[12];
- int i;
-
- tm_type.size = tm_type.alignment = 0;
- tm_type.elements = &tm_type_elements;
-
- for (i = 0; i < 9; i++)
- tm_type_elements[i] = &ffi_type_sint;
-
- tm_type_elements[9] = &ffi_type_slong;
- tm_type_elements[10] = &ffi_type_pointer;
- tm_type_elements[11] = NULL;
-
- /* tm_type can now be used to represent tm argument types and
- return types for ffi_prep_cif() */
- }
-
-
-
-Platform Specific Notes
-=======================
-
- Intel x86
- ---------
-
-There are no known problems with the x86 port.
-
- Sun Sparc - SunOS 4.1.3 & Solaris 2.x
- -------------------------------------
-
-There's a bug in the structure passing code for sparc processors.
-Struct arguments that are passed in value actually end up being passed
-by reference. This will be fixed Real Soon Now.
-
-"long long" values are not supported yet.
-
-You must use GNU Make to build libffi on Sun platforms.
-
- MIPS - Irix 5.3 & 6.x
- ---------------------
-
-Irix 6.2 and better supports three different calling conventions: o32,
-n32 and n64. Currently, libffi only supports both o32 and n32 under
-Irix 6.x, but only o32 under Irix 5.3. Libffi will automatically be
-configured for whichever calling convention it was built for.
-
-By default, the configure script will try to build libffi with the GNU
-development tools. To build libffi with the SGI development tools, set
-the environment variable CC to either "cc -32" or "cc -n32" before
-running configure under Irix 6.x (depending on whether you want an o32
-or n32 library), or just "cc" for Irix 5.3.
-
-With the n32 calling convention, when returning structures smaller
-than 16 bytes, be sure to provide an RVALUE that is 8 byte aligned.
-Here's one way of forcing this:
-
- double struct_storage[2];
- my_small_struct *s = (my_small_struct *) struct_storage;
- /* Use s for RVALUE */
-
-If you don't do this you are liable to get spurious bus errors.
-
-"long long" values are not supported yet.
-
-You must use GNU Make to build libffi on SGI platforms.
-
- ARM - System V ABI
- ------------------
-
-The ARM port was performed on a NetWinder running ARM Linux ELF
-(2.0.31) and gcc 2.8.1.
-
-
-
- PowerPC System V ABI
- --------------------
-
-There are two `System V ABI's which libffi implements for PowerPC.
-They differ only in how small structures are returned from functions.
-
-In the FFI_SYSV version, structures that are 8 bytes or smaller are
-returned in registers. This is what GCC does when it is configured
-for solaris, and is what the System V ABI I have (dated September
-1995) says.
-
-In the FFI_GCC_SYSV version, all structures are returned the same way:
-by passing a pointer as the first argument to the function. This is
-what GCC does when it is configured for linux or a generic sysv
-target.
-
-EGCS 1.0.1 (and probably other versions of EGCS/GCC) also has a
-inconsistency with the SysV ABI: When a procedure is called with many
-floating-point arguments, some of them get put on the stack. They are
-all supposed to be stored in double-precision format, even if they are
-only single-precision, but EGCS stores single-precision arguments as
-single-precision anyway. This causes one test to fail (the `many
-arguments' test).
-
-
-What's With The Crazy Comments?
-===============================
-
-You might notice a number of cryptic comments in the code, delimited
-by /*@ and @*/. These are annotations read by the program LCLint, a
-tool for statically checking C programs. You can read all about it at
-<http://larch-www.lcs.mit.edu:8001/larch/lclint/index.html>.
-
-
-History
-=======
-
-1.20 Oct-5-98
- Raffaele Sena produces ARM port.
-
-1.19 Oct-5-98
- Fixed x86 long double and long long return support.
- m68k bug fixes from Andreas Schwab.
- Patch for DU assembler compatibility for the Alpha from Richard
- Henderson.
-
-1.18 Apr-17-98
- Bug fixes and MIPS configuration changes.
-
-1.17 Feb-24-98
- Bug fixes and m68k port from Andreas Schwab. PowerPC port from
- Geoffrey Keating. Various bug x86, Sparc and MIPS bug fixes.
-
-1.16 Feb-11-98
- Richard Henderson produces Alpha port.
-
-1.15 Dec-4-97
- Fixed an n32 ABI bug. New libtool, auto* support.
-
-1.14 May-13-97
- libtool is now used to generate shared and static libraries.
- Fixed a minor portability problem reported by Russ McManus
- <mcmanr@eq.gs.com>.
-
-1.13 Dec-2-96
- Added --enable-purify-safety to keep Purify from complaining
- about certain low level code.
- Sparc fix for calling functions with < 6 args.
- Linux x86 a.out fix.
-
-1.12 Nov-22-96
- Added missing ffi_type_void, needed for supporting void return
- types. Fixed test case for non MIPS machines. Cygnus Support
- is now Cygnus Solutions.
-
-1.11 Oct-30-96
- Added notes about GNU make.
-
-1.10 Oct-29-96
- Added configuration fix for non GNU compilers.
-
-1.09 Oct-29-96
- Added --enable-debug configure switch. Clean-ups based on LCLint
- feedback. ffi_mips.h is always installed. Many configuration
- fixes. Fixed ffitest.c for sparc builds.
-
-1.08 Oct-15-96
- Fixed n32 problem. Many clean-ups.
-
-1.07 Oct-14-96
- Gordon Irlam rewrites v8.S again. Bug fixes.
-
-1.06 Oct-14-96
- Gordon Irlam improved the sparc port.
-
-1.05 Oct-14-96
- Interface changes based on feedback.
-
-1.04 Oct-11-96
- Sparc port complete (modulo struct passing bug).
-
-1.03 Oct-10-96
- Passing struct args, and returning struct values works for
- all architectures/calling conventions. Expanded tests.
-
-1.02 Oct-9-96
- Added SGI n32 support. Fixed bugs in both o32 and Linux support.
- Added "make test".
-
-1.01 Oct-8-96
- Fixed float passing bug in mips version. Restructured some
- of the code. Builds cleanly with SGI tools.
-
-1.00 Oct-7-96
- First release. No public announcement.
-
-
-Authors & Credits
-=================
-
-libffi was written by Anthony Green <green@cygnus.com>.
-
-Portions of libffi were derived from Gianni Mariani's free gencall
-library for Silicon Graphics machines.
-
-The closure mechanism was designed and implemented by Kresten Krab
-Thorup.
-
-The Sparc port was derived from code contributed by the fine folks at
-Visible Decisions Inc <http://www.vdi.com>. Further enhancements were
-made by Gordon Irlam at Cygnus Solutions <http://www.cygnus.com>.
-
-The Alpha port was written by Richard Henderson at Cygnus Solutions.
-
-Andreas Schwab ported libffi to m68k Linux and provided a number of
-bug fixes.
-
-Geoffrey Keating ported libffi to the PowerPC.
-
-Raffaele Sena ported libffi to the ARM.
-
-Jesper Skov and Andrew Haley both did more than their fair share of
-stepping through the code and tracking down bugs.
-
-Thanks also to Tom Tromey for bug fixes and configuration help.
-
-Thanks to Jim Blandy, who provided some useful feedback on the libffi
-interface.
-
-If you have a problem, or have found a bug, please send a note to
-green@cygnus.com.
projects / msp430-gcc.git / blobdiff