+++ /dev/null
-This is a rough history of garbage collector bugs and versions.
-
-This has been maintained with varying diligence over the years.
-
-I made an attempt to include recent contributors here. I apologize for any
-omissions.
-
--------------------------
-
- Version 1.3 and immediately preceding versions contained spurious
-assembly language assignments to TMP_SP. Only the assignment in the PC/RT
-code is necessary. On other machines, with certain compiler options,
-the assignments can lead to an unsaved register being overwritten.
-Known to cause problems under SunOS 3.5 WITHOUT the -O option. (With
--O the compiler recognizes it as dead code. It probably shouldn't,
-but that's another story.)
-
- Version 1.4 and earlier versions used compile time determined values
-for the stack base. This no longer works on Sun 3s, since Sun 3/80s use
-a different stack base. We now use a straightforward heuristic on all
-machines on which it is known to work (incl. Sun 3s) and compile-time
-determined values for the rest. There should really be library calls
-to determine such values.
-
- Version 1.5 and earlier did not ensure 8 byte alignment for objects
-allocated on a sparc based machine.
-
- Version 1.8 added ULTRIX support in gc_private.h.
-
- Version 1.9 fixed a major bug in gc_realloc.
-
- Version 2.0 introduced a consistent naming convention for collector
-routines and added support for registering dynamic library data segments
-in the standard mark_roots.c. Most of the data structures were revamped.
-The treatment of interior pointers was completely changed. Finalization
-was added. Support for locking was added. Object kinds were added.
-We added a black listing facility to avoid allocating at addresses known
-to occur as integers somewhere in the address space. Much of this
-was accomplished by adapting ideas and code from the PCR collector.
-The test program was changed and expanded.
-
- Version 2.1 was the first stable version since 1.9, and added support
-for PPCR.
-
- Version 2.2 added debugging allocation, and fixed various bugs. Among them:
-- GC_realloc could fail to extend the size of the object for certain large object sizes.
-- A blatant subscript range error in GC_printf, which unfortunately
- wasn't exercised on machines with sufficient stack alignment constraints.
-- GC_register_displacement did the wrong thing if it was called after
- any allocation had taken place.
-- The leak finding code would eventually break after 2048 byte
- byte objects leaked.
-- interface.c didn't compile.
-- The heap size remained much too small for large stacks.
-- The stack clearing code behaved badly for large stacks, and perhaps
- on HP/PA machines.
-
- Version 2.3 added ALL_INTERIOR_POINTERS and fixed the following bugs:
-- Missing declaration of etext in the A/UX version.
-- Some PCR root-finding problems.
-- Blacklisting was not 100% effective, because the plausible future
- heap bounds were being miscalculated.
-- GC_realloc didn't handle out-of-memory correctly.
-- GC_base could return a nonzero value for addresses inside free blocks.
-- test.c wasn't really thread safe, and could erroneously report failure
- in a multithreaded environment. (The locking primitives need to be
- replaced for other threads packages.)
-- GC_CONS was thoroughly broken.
-- On a SPARC with dynamic linking, signals stayed diabled while the
- client code was running.
- (Thanks to Manuel Serrano at INRIA for reporting the last two.)
-
- Version 2.4 added GC_free_space_divisor as a tuning knob, added
- support for OS/2 and linux, and fixed the following bugs:
-- On machines with unaligned pointers (e.g. Sun 3), every 128th word could
- fail to be considered for marking.
-- Dynamic_load.c erroneously added 4 bytes to the length of the data and
- bss sections of the dynamic library. This could result in a bad memory
- reference if the actual length was a multiple of a page. (Observed on
- Sun 3. Can probably also happen on a Sun 4.)
- (Thanks to Robert Brazile for pointing out that the Sun 3 version
- was broken. Dynamic library handling is still broken on Sun 3s
- under 4.1.1U1, but apparently not 4.1.1. If you have such a machine,
- use -Bstatic.)
-
- Version 2.5 fixed the following bugs:
-- Removed an explicit call to exit(1)
-- Fixed calls to GC_printf and GC_err_printf, so the correct number of
- arguments are always supplied. The OS/2 C compiler gets confused if
- the number of actuals and the number of formals differ. (ANSI C
- doesn't require this to work. The ANSI sanctioned way of doing things
- causes too many compatibility problems.)
-
- Version 3.0 added generational/incremental collection and stubborn
- objects.
-
- Version 3.1 added the following features:
-- A workaround for a SunOS 4.X SPARC C compiler
- misfeature that caused problems when the collector was turned into
- a dynamic library.
-- A fix for a bug in GC_base that could result in a memory fault.
-- A fix for a performance bug (and several other misfeatures) pointed
- out by Dave Detlefs and Al Dosser.
-- Use of dirty bit information for static data under Solaris 2.X.
-- DEC Alpha/OSF1 support (thanks to Al Dosser).
-- Incremental collection on more platforms.
-- A more refined heap expansion policy. Less space usage by default.
-- Various minor enhancements to reduce space usage, and to reduce
- the amount of memory scanned by the collector.
-- Uncollectable allocation without per object overhead.
-- More conscientious handling of out-of-memory conditions.
-- Fixed a bug in debugging stubborn allocation.
-- Fixed a bug that resulted in occasional erroneous reporting of smashed
- objects with debugging allocation.
-- Fixed bogus leak reports of size 4096 blocks with FIND_LEAK.
-
- Version 3.2 fixed a serious and not entirely repeatable bug in
- the incremental collector. It appeared only when dirty bit info
- on the roots was available, which is normally only under Solaris.
- It also added GC_general_register_disappearing_link, and some
- testing code. Interface.c disappeared.
-
- Version 3.3 fixes several bugs and adds new ports:
-- PCR-specific bugs.
-- Missing locking in GC_free, redundant FASTUNLOCK
- in GC_malloc_stubborn, and 2 bugs in
- GC_unregister_disappearing_link.
- All of the above were pointed out by Neil Sharman
- (neil@cs.mu.oz.au).
-- Common symbols allocated by the SunOS4.X dynamic loader
- were not included in the root set.
-- Bug in GC_finalize (reported by Brian Beuning and Al Dosser)
-- Merged Amiga port from Jesper Peterson (untested)
-- Merged NeXT port from Thomas Funke (significantly
- modified and untested)
-
- Version 3.4:
-- Fixed a performance bug in GC_realloc.
-- Updated the amiga port.
-- Added NetBSD and 386BSD ports.
-- Added cord library.
-- Added trivial performance enhancement for
- ALL_INTERIOR_POINTERS. (Don't scan last word.)
-
- Version 3.5
-- Minor collections now mark from roots only once, if that
- doesn't cause an excessive pause.
-- The stack clearing heuristic was refined to prevent anomalies
- with very heavily recursive programs and sparse stacks.
-- Fixed a bug that prevented mark stack growth in some cases.
- GC_objects_are_marked should be set to TRUE after a call
- to GC_push_roots and as part of GC_push_marked, since
- both can now set mark bits. I think this is only a performance
- bug, but I wouldn't bet on it. It's certainly very hard to argue
- that the old version was correct.
-- Fixed an incremental collection bug that prevented it from
- working at all when HBLKSIZE != getpagesize()
-- Changed dynamic_loading.c to include gc_priv.h before testing
- DYNAMIC_LOADING. SunOS dynamic library scanning
- must have been broken in 3.4.
-- Object size rounding now adapts to program behavior.
-- Added a workaround (provided by Manuel Serrano and
- colleagues) to a long-standing SunOS 4.X (and 3.X?) ld bug
- that I had incorrectly assumed to have been squished.
- The collector was broken if the text segment size was within
- 32 bytes of a multiple of 8K bytes, and if the beginning of
- the data segment contained interesting roots. The workaround
- assumes a demand-loadable executable. The original may have
- have "worked" in some other cases.
-- Added dynamic library support under IRIX5.
-- Added support for EMX under OS/2 (thanks to Ari Huttunen).
-
-Version 3.6:
-- fixed a bug in the mark stack growth code that was introduced
- in 3.4.
-- fixed Makefile to work around DEC AXP compiler tail recursion
- bug.
-
-Version 3.7:
-- Added a workaround for an HP/UX compiler bug.
-- Fixed another stack clearing performance bug. Reworked
- that code once more.
-
-Version 4.0:
-- Added support for Solaris threads (which was possible
- only by reimplementing some fraction of Solaris threads,
- since Sun doesn't currently make the thread debugging
- interface available).
-- Added non-threads win32 and win32S support.
-- (Grudgingly, with suitable muttering of obscenities) renamed
- files so that the collector distribution could live on a FAT
- file system. Files that are guaranteed to be useless on
- a PC still have long names. Gc_inline.h and gc_private.h
- still exist, but now just include gc_inl.h and gc_priv.h.
-- Fixed a really obscure bug in finalization that could cause
- undetected mark stack overflows. (I would be surprised if
- any real code ever tickled this one.)
-- Changed finalization code to dynamically resize the hash
- tables it maintains. (This probably does not matter for well-
- -written code. It no doubt does for C++ code that overuses
- destructors.)
-- Added typed allocation primitives. Rewrote the marker to
- accommodate them with more reasonable efficiency. This
- change should also speed up marking for GC_malloc allocated
- objects a little. See gc_typed.h for new primitives.
-- Improved debugging facilities slightly. Allocation time
- stack traces are now kept by default on SPARC/SUNOS4.
- (Thanks to Scott Schwartz.)
-- Added better support for small heap applications.
-- Significantly extended cord package. Fixed a bug in the
- implementation of lazily read files. Printf and friends now
- have cord variants. Cord traversals are a bit faster.
-- Made ALL_INTERIOR_POINTERS recognition the default.
-- Fixed de so that it can run in constant space, independent
- of file size. Added simple string searching to cords and de.
-- Added the Hull-Ellis C++ interface.
-- Added dynamic library support for OSF/1.
- (Thanks to Al Dosser and Tim Bingham at DEC.)
-- Changed argument to GC_expand_hp to be expressed
- in units of bytes instead of heap blocks. (Necessary
- since the heap block size now varies depending on
- configuration. The old version was never very clean.)
-- Added GC_get_heap_size(). The previous "equivalent"
- was broken.
-- Restructured the Makefile a bit.
-
-Since version 4.0:
-- Changed finalization implementation to guarantee that
- finalization procedures are called outside of the allocation
- lock, making direct use of the interface a little less dangerous.
- MAY BREAK EXISTING CLIENTS that assume finalizers
- are protected by a lock. Since there seem to be few multithreaded
- clients that use finalization, this is hopefully not much of
- a problem.
-- Fixed a gross bug in CORD_prev.
-- Fixed a bug in blacklst.c that could result in unbounded
- heap growth during startup on machines that do not clear
- memory obtained from the OS (e.g. win32S).
-- Ported de editor to win32/win32S. (This is now the only
- version with a mouse-sensitive UI.)
-- Added GC_malloc_ignore_off_page to allocate large arrays
- in the presence of ALL_INTERIOR_POINTERS.
-- Changed GC_call_with_alloc_lock to not disable signals in
- the single-threaded case.
-- Reduced retry count in GC_collect_or_expand for garbage
- collecting when out of memory.
-- Made uncollectable allocations bypass black-listing, as they
- should.
-- Fixed a bug in typed_test in test.c that could cause (legitimate)
- GC crashes.
-- Fixed some potential synchronization problems in finalize.c
-- Fixed a real locking problem in typd_mlc.c.
-- Worked around an AIX 3.2 compiler feature that results in
- out of bounds memory references.
-- Partially worked around an IRIX5.2 beta problem (which may
- or may not persist to the final release).
-- Fixed a bug in the heap integrity checking code that could
- result in explicitly deallocated objects being identified as
- smashed. Fixed a bug in the dbg_mlc stack saving code
- that caused old argument pointers to be considered live.
-- Fixed a bug in CORD_ncmp (and hence CORD_str).
-- Repaired the OS2 port, which had suffered from bit rot
- in 4.0. Worked around what appears to be CSet/2 V1.0
- optimizer bug.
-- Fixed a Makefile bug for target "c++".
-
-Since version 4.1:
-- Multiple bug fixes/workarounds in the Solaris threads version.
- (It occasionally failed to locate some register contents for
- marking. It also turns out that thr_suspend and friends are
- unreliable in Solaris 2.3. Dirty bit reads appear
- to be unreliable under some weird
- circumstances. My stack marking code
- contained a serious performance bug. The new code is
- extremely defensive, and has not failed in several cpu
- hours of testing. But no guarantees ...)
-- Added MacOS support (thanks to Patrick Beard.)
-- Fixed several syntactic bugs in gc_c++.h and friends. (These
- didn't bother g++, but did bother most other compilers.)
- Fixed gc_c++.h finalization interface. (It didn't.)
-- 64 bit alignment for allocated objects was not guaranteed in a
- few cases in which it should have been.
-- Added GC_malloc_atomic_ignore_off_page.
-- Added GC_collect_a_little.
-- Added some prototypes to gc.h.
-- Some other minor bug fixes (notably in Makefile).
-- Fixed OS/2 / EMX port (thanks to Ari Huttunen).
-- Fixed AmigaDOS port. (thanks to Michel Schinz).
-- Fixed the DATASTART definition under Solaris. There
- was a 1 in 16K chance of the collector missing the first
- 64K of static data (and thus crashing).
-- Fixed some blatant anachronisms in the README file.
-- Fixed PCR-Makefile for upcoming PPCR release.
-
-Since version 4.2:
-- Fixed SPARC alignment problem with GC_DEBUG.
-- Fixed Solaris threads /proc workaround. The real
- problem was an interaction with mprotect.
-- Incorporated fix from Patrick Beard for gc_c++.h (now gc_cpp.h).
-- Slightly improved allocator space utilization by
- fixing the GC_size_map mechanism.
-- Integrated some Sony News and MIPS RISCos 4.51
- patches. (Thanks to Nobuyuki Hikichi of
- Software Research Associates, Inc. Japan)
-- Fixed HP_PA alignment problem. (Thanks to
- xjam@cork.cs.berkeley.edu.)
-- Added GC_same_obj and friends. Changed GC_base
- to return 0 for pointers past the end of large objects.
- Improved GC_base performance with ALL_INTERIOR_POINTERS
- on machines with a slow integer mod operation.
- Added GC_PTR_ADD, GC_PTR_STORE, etc. to prepare
- for preprocessor.
-- changed the default on most UNIX machines to be that
- signals are not disabled during critical GC operations.
- This is still ANSI-conforming, though somewhat dangerous
- in the presence of signal handlers. But the performance
- cost of the alternative is sometimes problematic.
- Can be changed back with a minor Makefile edit.
-- renamed IS_STRING in gc.h, to CORD_IS_STRING, thus
- following my own naming convention. Added the function
- CORD_to_const_char_star.
-- Fixed a gross bug in GC_finalize. Symptom: occasional
- address faults in that function. (Thanks to Anselm
- Baird-Smith (Anselm.BairdSmith@inria.fr)
-- Added port to ICL DRS6000 running DRS/NX. Restructured
- things a bit to factor out common code, and remove obsolete
- code. Collector should now run under SUNOS5 with either
- mprotect or /proc dirty bits. (Thanks to Douglas Steel
- (doug@wg.icl.co.uk)).
-- More bug fixes and workarounds for Solaris 2.X. (These were
- mostly related to putting the collector in a dynamic library,
- which didn't really work before. Also SOLARIS_THREADS
- didn't interact well with dl_open.) Thanks to btlewis@eng.sun.com.
-- Fixed a serious performance bug on the DEC Alpha. The text
- segment was getting registered as part of the root set.
- (Amazingly, the result was still fast enough that the bug
- was not conspicuous.) The fix works on OSF/1, version 1.3.
- Hopefully it also works on other versions of OSF/1 ...
-- Fixed a bug in GC_clear_roots.
-- Fixed a bug in GC_generic_malloc_words_small that broke
- gc_inl.h. (Reported by Antoine de Maricourt. I broke it
- in trying to tweak the Mac port.)
-- Fixed some problems with cord/de under Linux.
-- Fixed some cord problems, notably with CORD_riter4.
-- Added DG/UX port.
- Thanks to Ben A. Mesander (ben@piglet.cr.usgs.gov)
-- Added finalization registration routines with weaker ordering
- constraints. (This is necessary for C++ finalization with
- multiple inheritance, since the compiler often adds self-cycles.)
-- Filled the holes in the SCO port. (Thanks to Michael Arnoldus
- <chime@proinf.dk>.)
-- John Ellis' additions to the C++ support: From John:
-
-* I completely rewrote the documentation in the interface gc_c++.h
-(later renamed gc_cpp.h). I've tried to make it both clearer and more
-precise.
-
-* The definition of accessibility now ignores pointers from an
-finalizable object (an object with a clean-up function) to itself.
-This allows objects with virtual base classes to be finalizable by the
-collector. Compilers typically implement virtual base classes using
-pointers from an object to itself, which under the old definition of
-accessibility prevented objects with virtual base classes from ever
-being collected or finalized.
-
-* gc_cleanup now includes gc as a virtual base. This was enabled by
-the change in the definition of accessibility.
-
-* I added support for operator new[]. Since most (all?) compilers
-don't yet support operator new[], it is conditionalized on
--DOPERATOR_NEW_ARRAY. The code is untested, but its trivial and looks
-correct.
-
-* The test program test_gc_c++ (later renamed test_cpp.cc)
-tries to test for the C++-specific functionality not tested by the
-other programs.
-- Added <unistd.h> include to misc.c. (Needed for ppcr.)
-- Added PowerMac port. (Thanks to Patrick Beard again.)
-- Fixed "srcdir"-related Makefile problems. Changed things so
- that all externally visible include files always appear in the
- include subdirectory of the source. Made gc.h directly
- includable from C++ code. (These were at Per
- Bothner's suggestion.)
-- Changed Intel code to also mark from ebp (Kevin Warne's
- suggestion).
-- Renamed C++ related files so they could live in a FAT
- file system. (Charles Fiterman's suggestion.)
-- Changed Windows NT Makefile to include C++ support in
- gc.lib. Added C++ test as Makefile target.
-
-Since version 4.3:
- - ASM_CLEAR_CODE was erroneously defined for HP
- PA machines, resulting in a compile error.
- - Fixed OS/2 Makefile to create a library. (Thanks to
- Mark Boulter (mboulter@vnet.ibm.com)).
- - Gc_cleanup objects didn't work if they were created on
- the stack. Fixed.
- - One copy of Gc_cpp.h in the distribution was out of
- synch, and failed to document some known compiler
- problems with explicit destructor invocation. Partially
- fixed. There are probably other compilers on which
- gc_cleanup is miscompiled.
- - Fixed Makefile to pass C compiler flags to C++ compiler.
- - Added Mac fixes.
- - Fixed os_dep.c to work around what appears to be
- a new and different VirtualQuery bug under newer
- versions of win32S.
- - GC_non_gc_bytes was not correctly maintained by
- GC_free. Fixed. Thanks to James Clark (jjc@jclark.com).
- - Added GC_set_max_heap_size.
- - Changed allocation code to ignore blacklisting if it is preventing
- use of a very large block of memory. This has the advantage
- that naive code allocating very large objects is much more
- likely to work. The downside is you might no
- longer find out that such code should really use
- GC_malloc_ignore_off_page.
- - Changed GC_printf under win32 to close and reopen the file
- between calls. FAT file systems otherwise make the log file
- useless for debugging.
- - Added GC_try_to_collect and GC_get_bytes_since_gc. These
- allow starting an abortable collection during idle times.
- This facility does not require special OS support. (Thanks to
- Michael Spertus of Geodesic Systems for suggesting this. It was
- actually an easy addition. Kumar Srikantan previously added a similar
- facility to a now ancient version of the collector. At the time
- this was much harder, and the result was less convincing.)
- - Added some support for the Borland development environment. (Thanks
- to John Ellis and Michael Spertus.)
- - Removed a misfeature from checksums.c that caused unexpected
- heap growth. (Thanks to Scott Schwartz.)
- - Changed finalize.c to call WARN if it encounters a finalization cycle.
- WARN is defined in gc_priv.h to write a message, usually to stdout.
- In many environments, this may be inappropriate.
- - Renamed NO_PARAMS in gc.h to GC_NO_PARAMS, thus adhering to my own
- naming convention.
- - Added GC_set_warn_proc to intercept warnings.
- - Fixed Amiga port. (Thanks to Michel Schinz (schinz@alphanet.ch).)
- - Fixed a bug in mark.c that could result in an access to unmapped
- memory from GC_mark_from_mark_stack on machines with unaligned
- pointers.
- - Fixed a win32 specific performance bug that could result in scanning of
- objects allocated with the system malloc.
- - Added REDIRECT_MALLOC.
-
-Since version 4.4:
- - Fixed many minor and one major README bugs. (Thanks to Franklin Chen
- (chen@adi.com) for pointing out many of them.)
- - Fixed ALPHA/OSF/1 dynamic library support. (Thanks to Jonathan Bachrach
- (jonathan@harlequin.com)).
- - Added incremental GC support (MPROTECT_VDB) for Linux (with some
- help from Bruno Haible).
- - Altered SPARC recognition tests in gc.h and config.h (mostly as
- suggested by Fergus Henderson).
- - Added basic incremental GC support for win32, as implemented by
- Windows NT and Windows 95. GC_enable_incremental is a noop
- under win32s, which doesn't implement enough of the VM interface.
- - Added -DLARGE_CONFIG.
- - Fixed GC_..._ignore_off_page to also function without
- -DALL_INTERIOR_POINTERS.
- - (Hopefully) fixed RS/6000 port. (Only the test was broken.)
- - Fixed a performance bug in the nonincremental collector running
- on machines supporting incremental collection with MPROTECT_VDB
- (e.g. SunOS 4, DEC AXP). This turned into a correctness bug under
- win32s with win32 incremental collection. (Not all memory protection
- was disabled.)
- - Fixed some ppcr related bit rot.
- - Caused dynamic libraries to be unregistered before reregistering.
- The old way turned out to be a performance bug on some machines.
- - GC_root_size was not properly maintained under MSWIN32.
- - Added -DNO_DEBUGGING and GC_dump.
- - Fixed a couple of bugs arising with SOLARIS_THREADS +
- REDIRECT_MALLOC.
- - Added NetBSD/M68K port. (Thanks to Peter Seebach
- <seebs@taniemarie.solon.com>.)
- - Fixed a serious realloc bug. For certain object sizes, the collector
- wouldn't scan the expanded part of the object. (Thanks to Clay Spence
- (cds@peanut.sarnoff.com) for noticing the problem, and helping me to
- track it down.)
-
-Since version 4.5:
- - Added Linux ELF support. (Thanks to Arrigo Triulzi <arrigo@ic.ac.uk>.)
- - GC_base crashed if it was called before any other GC_ routines.
- This could happen if a gc_cleanup object was allocated outside the heap
- before any heap allocation.
- - The heap expansion heuristic was not stable if all objects had finalization
- enabled. Fixed finalize.c to count memory in finalization queue and
- avoid explicit deallocation. Changed alloc.c to also consider this count.
- (This is still not recommended. It's expensive if nothing else.) Thanks
- to John Ellis for pointing this out.
- - GC_malloc_uncollectable(0) was broken. Thanks to Phong Vo for pointing
- this out.
- - The collector didn't compile under Linux 1.3.X. (Thanks to Fred Gilham for
- pointing this out.) The current workaround is ugly, but expected to be
- temporary.
- - Fixed a formatting problem for SPARC stack traces.
- - Fixed some '=='s in os_dep.c that should have been assignments.
- Fortunately these were in code that should never be executed anyway.
- (Thanks to Fergus Henderson.)
- - Fixed the heap block allocator to only drop blacklisted blocks in small
- chunks. Made BL_LIMIT self adjusting. (Both of these were in response
- to heap growth observed by Paul Graham.)
- - Fixed the Metrowerks/68K Mac code to also mark from a6. (Thanks
- to Patrick Beard.)
- - Significantly updated README.debugging.
- - Fixed some problems with longjmps out of signal handlers, especially under
- Solaris. Added a workaround for the fact that siglongjmp doesn't appear to
- do the right thing with -lthread under Solaris.
- - Added MSDOS/djgpp port. (Thanks to Mitch Harris (maharri@uiuc.edu).)
- - Added "make reserved_namespace" and "make user_namespace". The
- first renames ALL "GC_xxx" identifiers as "_GC_xxx". The second is the
- inverse transformation. Note that doing this is guaranteed to break all
- clients written for the other names.
- - descriptor field for kind NORMAL in GC_obj_kinds with ADD_BYTE_AT_END
- defined should be -ALIGNMENT not WORDS_TO_BYTES(-1). This is
- a serious bug on machines with pointer alignment of less than a word.
- - GC_ignore_self_finalize_mark_proc didn't handle pointers to very near the
- end of the object correctly. Caused failures of the C++ test on a DEC Alpha
- with g++.
- - gc_inl.h still had problems. Partially fixed. Added warnings at the
- beginning to hopefully specify the remaining dangers.
- - Added DATAEND definition to config.h.
- - Fixed some of the .h file organization. Fixed "make floppy".
-
-Since version 4.6:
- - Fixed some compilation problems with -DCHECKSUMS (thanks to Ian Searle)
- - Updated some Mac specific files to synchronize with Patrick Beard.
- - Fixed a serious bug for machines with non-word-aligned pointers.
- (Thanks to Patrick Beard for pointing out the problem. The collector
- should fail almost any conceivable test immediately on such machines.)
-
-Since version 4.7:
- - Changed a "comment" in a MacOS specific part of mach-dep.c that caused
- gcc to fail on other platforms.
-
-Since version 4.8
- - More README.debugging fixes.
- - Objects ready for finalization, but not finalized in the same GC
- cycle, could be prematurely collected. This occasionally happened
- in test_cpp.
- - Too little memory was obtained from the system for very large
- objects. That could cause a heap explosion if these objects were
- not contiguous (e.g. under PCR), and too much of them was blacklisted.
- - Due to an improper initialization, the collector was too hesitant to
- allocate blacklisted objects immediately after system startup.
- - Moved GC_arrays from the data into the bss segment by not explicitly
- initializing it to zero. This significantly
- reduces the size of executables, and probably avoids some disk accesses
- on program startup. It's conceivable that it might break a port that I
- didn't test.
- - Fixed EMX_MAKEFILE to reflect the gc_c++.h to gc_cpp.h renaming which
- occurred a while ago.
-
-Since 4.9:
- - Fixed a typo around a call to GC_collect_or_expand in alloc.c. It broke
- handling of out of memory. (Thanks to Patrick Beard for noticing.)
-
-Since 4.10:
- - Rationalized (hopefully) GC_try_to_collect in an incremental collection
- environment. It appeared to not handle a call while a collection was in
- progress, and was otherwise too conservative.
- - Merged GC_reclaim_or_delete_all into GC_reclaim_all to get rid of some
- code.
- - Added Patrick Beard's Mac fixes, with substantial completely untested
- modifications.
- - Fixed the MPROTECT_VDB code to deal with large pages and imprecise
- fault addresses (as on an UltraSPARC running Solaris 2.5). Note that this
- was not a problem in the default configuration, which uses PROC_VDB.
- - The DEC Alpha assembly code needed to restore $gp between calls.
- Thanks to Fergus Henderson for tracking this down and supplying a
- patch.
- - The write command for "de" was completely broken for large files.
- I used the easiest portable fix, which involved changing the semantics
- so that f.new is written instead of overwriting f. That's safer anyway.
- - Added README.solaris2 with a discussion of the possible problems of
- mixing the collector's sbrk allocation with malloc/realloc.
- - Changed the data segment starting address for SGI machines. The
- old code failed under IRIX6.
- - Required double word alignment for MIPS.
- - Various minor fixes to remove warnings.
- - Attempted to fix some Solaris threads problems reported by Zhiying Chen.
- In particular, the collector could try to fork a thread with the
- world stopped as part of GC_thr_init. It also failed to deal with
- the case in which the original thread terminated before the whole
- process did.
- - Added -DNO_EXECUTE_PERMISSION. This has a major performance impact
- on the incremental collector under Irix, and perhaps under other
- operating systems.
- - Added some code to support allocating the heap with mmap. This may
- be preferable under some circumstances.
- - Integrated dynamic library support for HP.
- (Thanks to Knut Tvedten <knuttv@ifi.uio.no>.)
- - Integrated James Clark's win32 threads support, and made a number
- of changes to it, many of which were suggested by Pontus Rydin.
- This is still not 100% solid.
- - Integrated Alistair Crooks' support for UTS4 running on an Amdahl
- 370-class machine.
- - Fixed a serious bug in explicitly typed allocation. Objects requiring
- large descriptors where handled in a way that usually resulted in
- a segmentation fault in the marker. (Thanks to Jeremy Fitzhardinge
- for helping to track this down.)
- - Added partial support for GNU win32 development. (Thanks to Fergus
- Henderson.)
- - Added optional support for Java-style finalization semantics. (Thanks
- to Patrick Bridges.) This is recommended only for Java implementations.
- - GC_malloc_uncollectable faulted instead of returning 0 when out of
- memory. (Thanks to dan@math.uiuc.edu for noticing.)
- - Calls to GC_base before the collector was initialized failed on a
- DEC Alpha. (Thanks to Matthew Flatt.)
- - Added base pointer checking to GC_REGISTER_FINALIZER in debugging
- mode, at the suggestion of Jeremy Fitzhardinge.
- - GC_debug_realloc failed for uncollectable objects. (Thanks to
- Jeremy Fitzhardinge.)
- - Explicitly typed allocation could crash if it ran out of memory.
- (Thanks to Jeremy Fitzhardinge.)
- - Added minimal support for a DEC Alpha running Linux.
- - Fixed a problem with allocation of objects whose size overflowed
- ptrdiff_t. (This now fails unconditionally, as it should.)
- - Added the beginning of Irix pthread support.
- - Integrated Xiaokun Zhu's fixes for djgpp 2.01.
- - Added SGI-style STL allocator support (gc_alloc.h).
- - Fixed a serious bug in README.solaris2. Multithreaded programs must include
- gc.h with SOLARIS_THREADS defined.
- - Changed GC_free so it actually deallocates uncollectable objects.
- (Thanks to Peter Chubb for pointing out the problem.)
- - Added Linux ELF support for dynamic libararies. (Thanks again to
- Patrick Bridges.)
- - Changed the Borland cc configuration so that the assembler is not
- required.
- - Fixed a bug in the C++ test that caused it to fail in 64-bit
- environments.
-
-Since 4.11:
- - Fixed ElfW definition in dyn_load.c. (Thanks to Fergus Henderson.)
- This prevented the dynamic library support from compiling on some
- older ELF Linux systems.
- - Fixed UTS4 port (which I apparently mangled during the integration)
- (Thanks to again to Alistair Crooks.)
- - "Make C++" failed on Suns with SC4.0, due to a problem with "bool".
- Fixed in gc_priv.h.
- - Added more pieces for GNU win32. (Thanks to Timothy N. Newsham.)
- The current state of things should suffice for at least some
- applications.
- - Changed the out of memory retry count handling as suggested by
- Kenjiro Taura. (This matters only if GC_max_retries > 0, which
- is no longer the default.)
- - If a /proc read failed repeatedly, GC_written_pages was not updated
- correctly. (Thanks to Peter Chubb for diagnosing this.)
- - Under unlikely circumstances, the allocator could infinite loop in
- an out of memory situation. (Thanks again to Kenjiro Taura for
- identifying the problem and supplying a fix.)
- - Fixed a syntactic error in the DJGPP code. (Thanks to Fergus
- Henderson for finding this by inspection.) Also fixed a test program
- problem with DJGPP (Thanks to Peter Monks.)
- - Atomic uncollectable objects were not treated correctly by the
- incremental collector. This resulted in weird log statistics and
- occasional performance problems. (Thanks to Peter Chubb for pointing
- this out.)
- - Fixed some problems resulting from compilers that dont define
- __STDC__. In this case void * and char * were used inconsistently
- in some cases. (Void * should not have been used at all. If
- you have an ANSI superset compiler that does not define __STDC__,
- please compile with -D__STDC__=0. Thanks to Manuel Serrano and others
- for pointing out the problem.)
- - Fixed a compilation problem on Irix with -n32 and -DIRIX_THREADS.
- Also fixed some other IRIX_THREADS problems which may or may not have
- had observable symptoms.
- - Fixed an HP PA compilation problem in dyn_load.c. (Thanks to
- Philippe Queinnec.)
- - SEGV fault handlers sometimes did not get reset correctly. (Thanks
- to David Pickens.)
- - Added a fix for SOLARIS_THREADS on Intel. (Thanks again to David
- Pickens.) This probably needs more work to become functional.
- - Fixed struct sigcontext_struct in os_dep.c for compilation under
- Linux 2.1.X. (Thanks to Fergus Henderson.)
- - Changed the DJGPP STACKBOTTOM and DATASTART values to those suggested
- by Kristian Kristensen. These may still not be right, but it is
- it is likely to work more often than what was there before. They may
- even be exactly right.
- - Added a #include <string.h> to test_cpp.cc. This appears to help
- with HP/UX and gcc. (Thanks to assar@sics.se.)
- - Version 4.11 failed to run in incremental mode on recent 64-bit Irix
- kernels. This was a problem related to page unaligned heap segments.
- Changed the code to page align heap sections on all platforms.
- (I had mistakenly identified this as a kernel problem earlier.
- It was not.)
- - Version 4.11 did not make allocated storage executable, except on
- one or two platforms, due to a bug in a #if test. (Thanks to Dave
- Grove for pointing this out.)
- - Added sparc_sunos4_mach_dep.s to support Sun's compilers under SunOS4.
- - Added GC_exclude_static_roots.
- - Fixed the object size mapping algorithm. This shouldn't matter,
- but the old code was ugly.
- - Heap checking code could die if one of the allocated objects was
- larger than its base address. (Unsigned underflow problem. Thanks
- to Clay Spence for isolating the problem.)
- - Added RS6000 (AIX) dynamic library support and fixed STACK_BOTTOM.
- (Thanks to Fred Stearns.)
- - Added Fergus Henderson's patches for improved robustness with large
- heaps and lots of blacklisting.
- - Added Peter Chubb's changes to support Solaris Pthreads, to support
- MMAP allocation in Solaris, to allow Solaris to find dynamic libraries
- through /proc, to add malloc_typed_ignore_off_page, and a few other
- minor features and bug fixes.
- - The Solaris 2 port should not use sbrk. I received confirmation from
- Sun that the use of sbrk and malloc in the same program is not
- supported. The collector now defines USE_MMAP by default on Solaris.
- - Replaced the djgpp makefile with Gary Leavens' version.
- - Fixed MSWIN32 detection test.
- - Added Fergus Henderson's patches to allow putting the collector into
- a DLL under GNU win32.
- - Added Ivan V. Demakov's port to Watcom C on X86.
- - Added Ian Piumarta's Linux/PowerPC port.
- - On Brian Burton's suggestion added PointerFreeGC to the placement
- options in gc_cpp.h. This is of course unsafe, and may be controversial.
- On the other hand, it seems to be needed often enough that it's worth
- adding as a standard facility.
-
-Since 4.12:
- - Fixed a crucial bug in the Watcom port. There was a redundant decl
- of GC_push_one in gc_priv.h.
- - Added FINALIZE_ON_DEMAND.
- - Fixed some pre-ANSI cc problems in test.c.
- - Removed getpagesize() use for Solaris. It seems to be missing in one
- or two versions.
- - Fixed bool handling for SPARCCompiler version 4.2.
- - Fixed some files in include that had gotten unlinked from the main
- copy.
- - Some RS/6000 fixes (missing casts). Thanks to Toralf Foerster.
- - Fixed several problems in GC_debug_realloc, affecting mostly the
- FIND_LEAK case.
- - GC_exclude_static_roots contained a buggy unsigned comparison to
- terminate a loop. (Thanks to Wilson Ho.)
- - CORD_str failed if the substring occurred at the last possible position.
- (Only affects cord users.)
- - Fixed Linux code to deal with RedHat 5.0 and integrated Peter Bigot's
- os_dep.c code for dealing with various Linux versions.
- - Added workaround for Irix pthreads sigaction bug and possible signal
- misdirection problems.
-Since alpha1:
- - Changed RS6000 STACKBOTTOM.
- - Integrated Patrick Beard's Mac changes.
- - Alpha1 didn't compile on Irix m.n, m < 6.
- - Replaced Makefile.dj with a new one from Gary Leavens.
- - Added Andrew Stitcher's changes to support SCO OpenServer.
- - Added PRINT_BLACK_LIST, to allow debugging of high densities of false
- pointers.
- - Added code to debug allocator to keep track of return address
- in GC_malloc caller, thus giving a bit more context.
- - Changed default behavior of large block allocator to more
- aggressively avoid fragmentation. This is likely to slow down the
- collector when it succeeds at reducing space cost.
- - Integrated Fergus Henderson's CYGWIN32 changes. They are untested,
- but needed for newer versions.
- - USE_MMAP had some serious bugs. This caused the collector to fail
- consistently on Solaris with -DSMALL_CONFIG.
- - Added Linux threads support, thanks largely to Fergus Henderson.
-Since alpha2:
- - Fixed more Linux threads problems.
- - Changed default GC_free_space_divisor to 3 with new large block allocation.
- (Thanks to Matthew Flatt for some measurements that suggest the old
- value sometimes favors space too much over time.)
- - More CYGWIN32 fixes.
- - Integrated Tyson-Dowd's Linux-M68K port.
- - Minor HP PA and DEC UNIX fixes from Fergus Henderson.
- - Integrated Christoffe Raffali's Linux-SPARC changes.
- - Allowed for one more GC fixup iteration after a full GC in incremental
- mode. Some quick measurements suggested that this significantly
- reduces pause times even with smaller GC_RATE values.
- - Moved some more GC data structures into GC_arrays. This decreases
- pause times and GC overhead, but makes debugging slightly less convenient.
- - Fixed namespace pollution problem ("excl_table").
- - Made GC_incremental a constant for -DSMALL_CONFIG, hopefully shrinking
- that slightly.
- - Added some win32 threads fixes.
- - Integrated Ivan Demakov and David Stes' Watcom fixes.
- - Various other minor fixes contributed by many people.
- - Renamed config.h to gcconfig.h, since config.h tends to be used for
- many other things.
- - Integrated Matthew Flatt's support for 68K MacOS "far globals".
- - Fixed up some of the dynamic library Makefile targets for consistency
- across platforms.
- - Fixed a USE_MMAP typo that caused out-of-memory handling to fail
- on Solaris.
- - Added code to test.c to test thread creation a bit more.
- - Integrated GC_win32_free_heap, as suggested by Ivan Demakov.
- - Fixed Solaris 2.7 stack base finding problem. (This may actually
- have been done in an earlier alpha release.)
-Since alpha3:
- - Fixed MSWIN32 recognition test, which interfered with cygwin.
- - Removed unnecessary gc_watcom.asm from distribution. Removed
- some obsolete README.win32 text.
- - Added Alpha Linux incremental GC support. (Thanks to Philipp Tomsich
- for code for retrieving the fault address in a signal handler.)
- Changed Linux signal handler context argument to be a pointer.
- - Took care of some new warnings generated by the 7.3 SGI compiler.
- - Integrated Phillip Musumeci's FreeBSD/ELF fixes.
- - -DIRIX_THREADS was broken with the -o32 ABI (typo in gc_priv.h>
-
-Since 4.13:
- - Fixed GC_print_source_ptr to not use a prototype.
- - generalized CYGWIN test.
- - gc::new did the wrong thing with PointerFreeGC placement.
- (Thanks to Rauli Ruohonen.)
- - In the ALL_INTERIOR_POINTERS (default) case, some callee-save register
- values could fail to be scanned if the register was saved and
- reused in a GC frame. This showed up in verbose mode with gctest
- compiled with an unreleased SGI compiler. I vaguely recall an old
- bug report that may have been related. The bug was probably quite old.
- (The problem was that the stack scanning could be deferred until
- after the relevant frame was overwritten, and the new save location
- might be outside the scanned area. Fixed by more eager stack scanning.)
- - PRINT_BLACK_LIST had some problems. A few source addresses were garbage.
- - Replaced Makefile.dj and added -I flags to cord make targets.
- (Thanks to Gary Leavens.)
- - GC_try_to_collect was broken with the nonincremental collector.
- - gc_cleanup destructors could pass the wrong address to
- GC_register_finalizer_ignore_self in the presence of multiple
- inheritance. (Thanks to Darrell Schiebel.)
- - Changed PowerPC Linux stack finding code.
-
-Since 4.14alpha1
- - -DSMALL_CONFIG did not work reliably with large (> 4K) pages.
- Recycling the mark stack during expansion could result in a size
- zero heap segment, which confused things. (This was probably also an
- issue with the normal config and huge pages.)
- - Did more work to make sure that callee-save registers were scanned
- completely, even with the setjmp-based code. Added USE_GENERIC_PUSH_REGS
- macro to facilitate testing on machines I have access to.
- - Added code to explicitly push register contents for win32 threads.
- This seems to be necessary. (Thanks to Pierre de Rop.)
-
-Since 4.14alpha2
- - changed STACKBOTTOM for DJGPP (Thanks to Salvador Eduardo Tropea).
-
-Since 4.14
- - Reworked large block allocator. Now uses multiple doubly linked free
- lists to approximate best fit.
- - Changed heap expansion heuristic. Entirely free blocks are no longer
- counted towards the heap size. This seems to have a major impact on
- heap size stability; the old version could expand the heap way too
- much in the presence of large block fragmentation.
- - added -DGC_ASSERTIONS and some simple assertions inside the collector.
- This is mainlyt for collector debugging.
- - added -DUSE_MUNMAP to allow the heap to shrink. Suupported on only
- a few UNIX-like platforms for now.
- - added GC_dump_regions() for debugging of fragmentation issues.
- - Changed PowerPC pointer alignment under Linux to 4. (This needs
- checking by someone who has one. The suggestions came to me via a
- rather circuitous path.)
- - Changed the Linux/Alpha port to walk the data segment backwards until
- it encounters a SIGSEGV. The old way to find the start of the data
- segment broke with a recent release.
- - cordxtra.c needed to call GC_REGISTER_FINALIZER instead of
- GC_register_finalizer, so that it would continue to work with GC_DEBUG.
- - allochblk sometimes cleared the wrong block for debugging purposes
- when it dropped blacklisted blocks. This could result in spurious
- error reports with GC_DEBUG.
- - added MACOS X Server support. (Thanks to Andrew Stone.)
- - Changed the Solaris threads code to ignore stack limits > 8 MB with
- a warning. Empirically, it is not safe to access arbitrary pages
- in such large stacks. And the dirty bit implementation does not
- guarantee that none of them will be accessed.
- - Integrated Martin Tauchmann's Amiga changes.
- - Integrated James Dominy's OpenBSD/SPARC port.
-
-Since 5.0alpha1
- - Fixed bugs introduced in alpha1 (OpenBSD & large block initialization).
- - Added -DKEEP_BACK_PTRS and backptr.h interface. (The implementation
- idea came from Al Demers.)
-
-Since 5.0alpha2
- - Added some highly incomplete code to support a copied young generation.
- Comments on nursery.h are appreciated.
- - Changed -DFIND_LEAK, -DJAVA_FINALIZATION, and -DFINALIZE_ON_DEMAND,
- so the same effect could be obtained with a runtime switch. This is
- a step towards standardizing on a single dynamic GC library.
- - Significantly changed the way leak detection is handled, as a consequence
- of the above.
-
-Since 5.0 alpha3
- - Added protection fault handling patch for Linux/M68K from Fergus
- Henderson and Roman Hodek.
- - Removed the tests for SGI_SOURCE in new_gc_alloc.h. This was causing that
- interface to fail on nonSGI platforms.
- - Changed the Linux stack finding code to use /proc, after changing it
- to use HEURISTIC1. (Thanks to David Mossberger for pointing out the
- /proc hook.)
- - Added HP/UX incremental GC support and HP/UX 11 thread support.
- Thread support is currently still flakey.
- - Added basic Linux/IA64 support.
- - Integrated Anthony Green's PicoJava support.
- - Integrated Scott Ananian's StrongARM/NetBSD support.
- - Fixed some fairly serious performance bugs in the incremental
- collector. These have probably been there essentially forever.
- (Mark bits were sometimes set before scanning dirty pages.
- The reclaim phase unnecessarily dirtied full small object pages.)
- - Changed the reclaim phase to ignore nearly full pages to avoid
- touching them.
- - Limited GC_black_list_spacing to roughly the heap growth increment.
- - Changed full collection triggering heuristic to decrease full GC
- frequency by default, but to explicitly trigger full GCs during
- heap growth. This doesn't always improve things, but on average it's
- probably a win.
- - GC_debug_free(0, ...) failed. Thanks to Fergus Henderson for the
- bug report and fix.
-
-Since 5.0 alpha4
- - GC_malloc_explicitly_typed and friends sometimes failed to
- initialize first word.
- - Added allocation routines and support in the marker for mark descriptors
- in a type structure referenced by the first word of an object. This was
- introduced to support gcj, but hopefully in a way that makes it
- generically useful.
- - Added GC_requested_heapsize, and inhibited collections in nonincremental
- mode if the actual used heap size is less than what was explicitly
- requested.
- - The Solaris pthreads version of GC_pthread_create didn't handle a NULL
- attribute pointer. Solaris thread support used the wrong default thread
- stack size. (Thanks to Melissa O'Neill for the patch.)
- - Changed PUSH_CONTENTS macro to no longer modify first parameter.
- This usually doesn't matter, but it was certainly an accident waiting
- to happen ...
- - Added GC_register_finalizer_no_order and friends to gc.h. They're
- needed by Java implementations.
- - Integrated a fix for a win32 deadlock resulting from clock() calling
- malloc. (Thanks to Chris Dodd.)
- - Integrated Hiroshi Kawashima's port to Linux/MIPS. This was designed
- for a handheld platform, and may or may not be sufficient for other
- machines.
- - Fixed a va_arg problem with the %c specifier in cordprnt.c. It appears
- that this was always broken, but recent versions of gcc are the first to
- report the (statically detectable) bug.
- - Added an attempt at a more general solution to dlopen races/deadlocks.
- GC_dlopen now temporarily disables collection. Still not ideal, but ...
- - Added -DUSE_I686_PREFETCH, -DUSE_3DNOW_PREFETCH, and support for IA64
- prefetch instructions. May improve performance measurably, but I'm not
- sure the code will run correctly on processors that don't support the
- instruction. Won't build except with very recent gcc.
- - Added caching for header lookups in the marker. This seems to result
- in a barely measurable performance gain. Added support for interleaved
- lookups of two pointers, but unconfigured that since the performance
- gain is currently near zero, and it adds to code size.
- - Changed Linux DATA_START definition to check both data_start and
- __data_start, since nothing else seems to be portable.
- - Added -DUSE_LD_WRAP to optionally take advantage of the GNU ld function
- wrapping mechanism. Probably currently useful only on Linux.
- - Moved some variables for the scratch allocator into GC_arrays, on
- Martin Hirzel's suggestion.
- - Fixed a win32 threads bug that caused the collector to not look for
- interior pointers from one of the thread stacks without
- ALL_INTERIOR_POINTERS. (Thanks to Jeff Sturm.)
- - Added Mingw32 support. (Thanks again to Jeff Sturm for the patch.)
- - Changed the alpha port to use the generic register scanning code instead
- of alpha_mach_dep.s. Alpha_mach_dep.s doesn't look for pointers in fp
- registers, but gcc sometimes spills pointers there. (Thanks to Manuel
- Serrano for helping me debug this by email.) Changed the IA64 code to
- do something similar for similar reasons.
-
-[5.0alpha5 doesn't really exist, but it may have escaped.]
-
-Since 5.0alpha6:
- - -DREDIRECT_MALLOC was broken in alpha6. Fixed.
- - Cleaned up gc_ccp.h slightly, thus also causing the HP C++ compiler to
- accept it.
- - Removed accidental reference to dbg_mlc.c, which caused dbg_mlc.o to be
- linked into every executable.
- - Added PREFETCH to bitmap marker. Changed it to use the header cache.
- - GC_push_marked sometimes pushed one object too many, resulting in a
- segmentation fault in GC_mark_from_mark_stack. This was probably an old
- bug. It finally showed up in gctest on win32.
- - Gc_priv.h erroneously #defined GC_incremental to be TRUE instead of FALSE
- when SMALL_CONFIG was defined. This was no doubt a major performance bug for
- the default win32 configuration.
- - Removed -DSMALL_CONFIG from NT_MAKEFILE. It seemed like an anchronism now
- that the average PC has 64MB or so.
- - Integrated Bryce McKinley's patches for linux threads and dynamic loading
- from the libgcj tree. Turned on dynamic loading support for Linux/PPC.
- - Changed the stack finding code to use environ on HP/UX. (Thanks
- to Gustavo Rodriguez-Rivera for the suggestion.) This should probably
- be done on other platforms, too. Since I can't test those, that'll
- wait until after 5.0.
-
-Since 5.0alpha7:
- - Fixed threadlibs.c for linux threads. -DUSE_LD_WRAP was broken and
- -ldl was omitted. Fixed Linux stack finding code to handle
- -DUSE_LD_WRAP correctly.
- - Added MSWIN32 exception handler around marker, so that the collector
- can recover from root segments that are unmapped during the collection.
- This caused occasional failures under Windows 98, and may also be
- an issue under Windows NT/2000.
-
-Since 5.0
- - Fixed a gc.h header bug which showed up under Irix. (Thanks to
- Dan Sullivan.)
- - Fixed a typo in GC_double_descr in typd_mlc.c.
- This probably could result in objects described by array descriptors not
- getting traced correctly. (Thanks to Ben Hutchings for pointing this out.)
- - The block nearly full tests in reclaim.c were not correct for 64 bit
- environments. This could result in unnecessary heap growth under unlikely
- conditions.
-
-Since 5.1
- - dyn_load.c declared GC_scratch_last_end_ptr as an extern even if it
- was defined as a macro. This prevented the collector from building on
- Irix.
- - We quietly assumed that indirect mark descriptors were never 0.
- Our own typed allocation interface violated that. This could result
- in segmentation faults in the marker with typed allocation.
- - Fixed a _DUSE_MUNMAP bug in the heap block allocation code.
- (Thanks to Ben Hutchings for the patch.)
- - Taught the collector about VC++ handling array operator new.
- (Thanks again to Ben Hutchings for the patch.)
- - The two copies of gc_hdrs.h had diverged. Made one a link to the other
- again.
-
-Since 5.2 (A few 5.2 patches are not in 6.0alpha1)
- - Fixed _end declaration for OSF1.
- - There were lots of spurious leak reports in leak detection mode, caused
- by the fact that some pages were not being swept, and hence unmarked
- objects weren't making it onto free lists. (This bug dated back to 5.0.)
- - Fixed a typo in the liblinuxgc.so Makefile rule.
- - Added the GetExitCodeThread to Win32 GC_stop_world to (mostly) work
- around a Windows 95 GetOpenFileName problem. (Thanks to Jacob Navia.)
-
-Since 5.3
- - Fixed a typo that prevented compilation with -DUSE_3DNOW_PREFETCH.
- (Thanks to Shawn Wagner for actually testing this.)
- - Fixed GC_is_thread_stack in solaris_threads.c. It forgot to return a value
- in the common case. I wonder why nobody noticed?
- - Fixed another silly syntax problem in GC_double_descr. (Thanks to
- Fergus Henderson for finding it.)
- - Fixed a GC_gcj_malloc bug: It tended to release the allocator lock twice.
-
-Since 5.4 (A few 5.3 patches are not in 6.0alpha2)
- - Added HP/PA prefetch support.
- - Added -DDBG_HDRS_ALL and -DSHORT_DBG_HDRS to reduce the cost and improve
- the reliability of generating pointer backtrace information, e.g. in
- the Bigloo environment.
- - Added parallel marking support (-DPARALLEL_MARK). This currently
- works only under IA32 and IA64 Linux, but it shouldn't be hard to adapt
- to other platforms. This is intended to be a lighter-weight (less
- new code, probably not as scalable) solution than the work by Toshio Endo
- et al, at the University of Tokyo. A number of their ideas were
- reused, though the code wasn't, and the underlying data structure
- is significantly different. In particular, we keep the global mark
- stack as a single shared data structure, but most of the work is done
- on smaller thread-local mark stacks.
- - Changed GC_malloc_many to be cheaper, and to require less mutual exclusion
- with -DPARALLEL_MARK.
- - Added full support for thread local allocation under Linux
- (-DTHREAD_LOCAL_ALLOC). This is a thin veneer on GC_malloc_many, and
- should be easily portable to other platforms, especially those that
- support pthreads.
- - CLEAR_DOUBLE was not always getting invoked when it should have been.
- - GC_gcj_malloc and friends used different out of memory handling than
- everything else, probably because I forgot about one when I implemented
- the other. They now both call GC_oom_fn(), not GC_oom_action().
- - Integrated Jakub Jelinek's fixes for Linux/SPARC.
- - Moved GC_objfreelist, GC_aobjfreelist, and GC_words_allocd out of
- GC_arrays, and separately registered the first two as excluded roots.
- This makes code compiled with gc_inl.h less dependent on the
- collector version. (It would be nice to remove the inclusion of
- gc_priv.h by gc_inl.h completely, but we're not there yet. The
- locking definitions in gc_priv.h are still referenced.)
- This change was later coniditoned on SEPARATE_GLOBALS, which
- is not defined by default, since it involves a performance hit.
- - Register GC_obj_kinds separately as an excluded root region. The
- attempt to register it with GC_arrays was usually failing. (This wasn't
- serious, but seemed to generate some confusion.)
- - Moved backptr.h to gc_backptr.h.
-
-Since 6.0alpha1
- - Added USE_MARK_BYTES to reduce the need for compare-and-swap on platforms
- for which that's expensive.
- - Fixed a locking bug ib GC_gcj_malloc and some locking assertion problems.
- - Added a missing volatile to OR_WORD and renamed the parameter to
- GC_compare_and_swap so it's not a C++ reserved word. (Thanks to
- Toshio Endo for pointing out both of those.)
- - Changed Linux dynamic library registration code to look at /proc/self/maps
- instead of the rld data structures when REDIRECT_MALLOC is defined.
- Otherwise some of the rld data data structures may be prematurely garbage
- collected. (Thanks to Eric Benson for helping to track this down.)
- - Fixed USE_LD_WRAP a bit more, so it should now work without threads.
- - Renamed XXX_THREADS macros to GC_XXX_THREADS for namespace correctness.
- Tomporarily added some backward compatibility definitions. Renamed
- USE_LD_WRAP to GC_USE_LD_WRAP.
- - Many MACOSX POWERPC changes, some additions to the gctest output, and
- a few minor generic bug fixes. (Thanks to Dietmar Planitzer.)
-
-Since 6.0 alpha2
- - Fixed the /proc/self/maps code to not seek, since that apparently is not
- reliable across all interesting kernels.
- - Fixed some compilation problems in the absence of PARALLEL_MARK
- (introduced in alpha2).
- - Fixed an algorithmic problem with PARALLEL_MARK. If work needs to
- be given back to the main mark "stack", the BOTTOM entries of the local
- stack should be given away, not the top ones. This has substantial
- performance impact, especially for > 2 processors, from what I can tell.
- - Extracted gc_lock.h from gc_priv.h. This should eventually make it a
- bit easier to avoid including gc_priv.h in clients.
- - Moved all include files to include/ and removed duplicate links to the
- same file. The old scheme was a bad idea because it was too easy to get the
- copies out of sync, and many systems don't support hard links.
- Unfortunately, it's likely that I broke some of the non-Unix Makefiles in
- the process, although I tried to update them appropriately.
- - Removed the partial support for a copied nursery. It's not clear that
- this would be a tremendous win, since we don't consistently lose to
- generational copying collectors. And it would significantly complicate
- many things. May be reintroduced if/when it really turns out to win.
- - Removed references to IRIX_JDK_THREADS, since I believe there never
- were and never will be any clients.
- - Added some code to linux_threads.c to possibly support HPUX threads
- using the Linux code. Unfortunately, it doesn't work yet, and is
- currently disabled.
- - Added support under Linux/X86 for saving the call chain, both in (debug)
- objects for client debugging, and in GC_arrays._last_stack for GC
- debugging. This was previously supported only under Solaris. It is
- not enabled by default under X86, since it requires that code be compiled
- to explicitly dave frame pointers on the call stack. (With gcc this
- currently happens by default, but is often turned off explicitly.)
- To turn it on, define SAVE_CALL_CHAIN.
-
-Since 6.0 alpha3
- - Moved up the detection of mostly full blocks to the initiatiation of the
- sweep phase. This eliminates some lock conention in the PARALLEL_MARK case,
- as multiple threads try to look at mostly full blocks concurrently.
- - Restored the code in GC_malloc_many that grabs a prefix of the global
- free list. This avoids the case in which every GC_malloc_many call
- tries and fails to allocate a new heap block, and the returns a single
- object from the global free list.
- - Some minor fixes in new_hblk.c. (Attempted to build free lists in order
- of increasing addresses instead of decreasing addresses for cache performance
- reasons. But this seems to be only a very minor gain with -DEAGER_SWEEP,
- and a loss in other cases. So the change was backed out.)
- - Fixed some of the documentation. (Thanks in large part to Fergus
- Henderson.)
- - Fixed the Linux USE_PROC_FOR_LIBRARIES code to deal with apps that perform
- large numbers of mmaps. (Thanks to Eric Benson.) Also fixed that code to
- deal with short reads.
- - Added GC_get_total_bytes().
- - Fixed leak detection mode to avoid spurious messages under linuxthreads.
- (This should also now be easy for the other supported threads packages.
- But the code is tricky enough that I'm hesitant to do it without being able
- to test. Everything allocated in the GC thread support itself should be
- explicitly deallocated.)
- - Made it possible (with luck) to redirect malloc to GC_local_malloc.
-
-Since 6.0 alpha4
- - Changed the definition of GC_pause in linux_threads.c to use a volatile
- asm. Some versions of gcc apparently optimize away writes to local volatile
- variables. This caused poor locking behaviour starting at about
- 4 processors.
- - Added GC_start_blocking(), GC_end_blocking() calls and wrapper for sleep
- to linux_threads.c.
- The first two calls could be used to generally avoid sending GC signals to
- blocked threads, avoiding both premature wakeups and unnecessary overhead.
- - Fixed a serious bug in thread-local allocation. At thread termination,
- GC_free could get called on small integers. Changed the code for thread
- termination to more efficiently return left-over free-lists.
- - Integrated Kjetil Matheussen's BeOS support.
- - Rearranged the directory structure to create the doc and tests
- subdirectories.
- - Sort of integrated Eric Benson's patch for OSF1. This provided basic
- OSF1 thread support by suitably extending hpux_irix_threads.c. Based
- on earlier email conversations with David Butenhof, I suspect that it
- will be more reliable in the long run to base this on linux_threads.c
- instead. Thus I attempted to patch up linux_threads.c based on Eric's code.
- The result is almost certainly broken, but hopefully close enough that
- someone with access to a machine can pick it up.
- - Integrated lots of minor changes from the NetBSD distribution. (These
- were supplied by David Brownlee. I'm not sure about the original
- authors.)
- - Hacked a bit more on the HP/UX thread-support in linux_threads.c. It
- now appears to work in the absence of incremental collection. Renamed
- hpux_irix_threads.c back to irix_threads.c, and removed the attempt to
- support HPUX there.
- - Changed gc.h to define _REENTRANT in cases in which it should already
- have been defined. It is still safer to also define it on the command
- line.
-
-Since 6.0alpha5:
- - Changed the definition of DATASTART on ALPHA and IA64, where data_start
- and __data_start are not defined by earlier versions of glibc. This might
- need to be fixed on other platforms as well.
- - Changed the way the stack base and backing store base are found on IA64.
- This should now remain reliable on future kernels. But since it relies
- on /proc, it will no longer work in the simulated NUE environment.
- - Made the call to random() in dbg_mlc.c with -DKEEP_BACK_PTRS dependent
- on the OS. On non-Unix systems, rand() should be used instead. Handled
- small RAND_MAX. (Thanks to Peter Ross for pointing this out.)
- - Fixed the cord make rules to create the cord subdirectory, if necessary.
- (Thanks to Doug Moen.)
- - Changed fo_object_size calculation in finalize.c. Turned finalization
- of nonheap object into a no-op. Removed anachronism from GC_size()
- implementation.
- - Changed GC_push_dirty call in solaris_threads.c to GC_push_selected.
- It was missed in a previous renaming. (Thanks to Vladimir Tsichevski
- for pointing this out.)
- - Arranged to not not mask SIGABRT in linux_threads.c. (Thanks to Bryce
- McKinlay.)
- - Added GC_no_dls hook for applications that want to register their own
- roots.
- - Integrated Kjetil Matheussen's Amiga changes.
- - Added FREEBSD_STACKBOTTOM. Changed the X86/FreeBSD port to use it.
- (Thanks to Matthew Flatt.)
- - Added pthread_detach interception for platforms supported by linux_threads.c
- and irix_threads.c. Should also be added for Solaris?
- - Changed the USE_MMAP code to check for the case in which we got the
- high end of the address space, i.e. mem_ptr + mem_sz == 0. It appears
- that this can happen under Solaris 7. It seems to be allowed by what
- I would claim is an oversight in the mmap specification. (Thanks to Toshio
- Endo for pointing out the problem.)
- - Cleanup of linux_threads.c. Some code was originally cloned from
- irix_threads.c and now unnecessary. Some comments were obviously wrong.
- - (Mostly) fixed a longstanding problem with setting of dirty bits from
- a signal handler. In the presence of threads, dirty bits could get lost,
- since the etting of a bit in the bit vector was not atomic with respect
- to other updates. The fix is 100% correct only for platforms for which
- GC_test_and_set is defined. The goal is to make that all platforms with
- thread support. Matters only if incremental GC and threads are both
- enabled.
- - made GC_all_interior_pointers (a.k.a. ALL_INTERIOR_POINTERS) an
- initialization time, instead of build-time option. This is a
- nontrivial, high risk change. It should slow down the code measurably
- only if MERGE_SIZES is not defined, which is a very nonstandard
- configuration.
- - Added doc/README.environment, and implemented what it describes. This
- allows a number of additional configuration options to be set through
- the environment. It documents a few previously undocumented options.
- - Integrated Eric Benson's leak testing improvements.
- - Removed the option to throw away the beginning of each page (DISCARD_WORDS).
- This became less and less useful as processors enforce stricter alignment.
- And it hadn't been tested in ages, and was thus probably broken anyway.
-
-Since 6.0alpha6:
- - Added GC_finalizer_notifier. Fixed GC_finalize_on_demand. (The variable
- actually wasn't being tested at the right points. The build-time flag
- was.)
- - Added Tom Tromey's S390 Linux patch.
- - Added code to push GC_finalize_now in GC_push_finalizer_structures.
- (Thanks to Matthew Flatt.)
- - Added GC_push_gc_structures() to push all GC internal roots.
- - Integrated some FreeBSD changes from Matthew Flatt.
- - It looks like USRSTACK is not always correctly defined under Solaris.
- Hacked gcconfig.h to attempt to work around the problem. The result
- is not well tested. (Thanks again to Matthew Flatt for pointing this
- out. The gross hack is mine. - HB)
- - Added Ji-Yong Chung's win32 threads and C++ fixes.
- - Arranged for hpux_test_and_clear.s to no longer be needed or built.
- It was causing build problems with gas, and it's not clear this is
- better than the pthreads alternative on this platform.
- - Some MINGW32 fixes from Hubert Garavel.
- - Added Initial Hitachi SH4 port from Kaz Kojima.
- - Ported thread-local allocation and parallel mark code to HP/UX on PA_RISC.
- - Made include/gc_mark.h more public and separated out the really private
- pieces. This is probably still not quite sufficient for clients that
- want to supply their own kind of type information. But it's a start.
- This involved lots of identifier renaming to make it namespace clean.
- - Added GC_dont_precollect for clients that need complete control over
- the root set.
- - GC_is_visible didn't do the right thing with gcj objects. (Not that
- many people are likely to care, but ...)
- - Don't redefine read with GC_USE_LD_WRAP.
- - Initial port to LINUX/HP_PA. Incremental collection and threads are not
- yet supported. (Incremental collection should work if you have the
- right kernel. Threads may work with a sufficiently patched pthread
- library.)
- - Changed gcconfig.h to recognize __i386__ as an alternative to i386 in
- many places. (Thanks to Benjamin Lerman.)
- - Made win32_threads.c more tolerant of detaching a thread that it didn't
- know about. (Thanks to Paul Nash.)
- - Added Makefile.am and configure.in from gcc to the distribution, with
- minimal changes. For the moment, those are just placeholders. In the
- future, we're planning to switch to a GNU-style build environment for
- Un*x-like systems, though the old Makefile will remain as a backup.
- - Turned off STUBBORN_ALLOC by default, and added it back as a Makefile
- option.
- - Redistributed some functions between malloc.c and mallocx.c, so that
- simple statically linked apps no longer pull in mallocx.o.
- - Changed large object allocation to clear the first and last few words
- of each block before releassing the lock. Otherwise the marker could see
- objects with nonsensical type descriptors.
- - Fixed a couple of subtle problems that could result in not recognizing
- interior pointers from the stack. (I believe these were introduced
- in 6.0alpha6.)
- - GC_debug_free_inner called GC_free, which tried to reacquire the
- allocator lock, and hence deadlocked. (DBG_HDRS_ALL probably never worked
- with threads?)
- - Fixed several problems with back traces. Accidental references to a free
- list could cause the free list pointer to be overwritten by a back pointer.
- There seemed to be some problems with the encoding of root and finalizer
- references.
-
-Since 6.0alpha7:
- - Changed GC_debug_malloc_replacement and GC_debug_realloc_replacement
- so that they compile under Irix. (Thanks to Dave Love.)
- - Updated powerpc_macosx_mach_dep.s so that it works if the collector
- is in a dynamic library. (Thanks to Andrew Begel.)
- - Transformed README.debugging into debugging.html, updating and
- expanding it in the process. Added gcdescr.html and tree.html
- from the web site to the GC distribution.
- - Fixed several problems related to PRINT_BLACK_LIST. This involved
- restructuring some of the marker macros.
- - Fixed some problems with the sizing of objects with debug information.
- Finalization was broken KEEP_BACK_PTRS or PRINT_BLACK_LIST. Reduced the
- object size with SHORT_DEBUG_HDRS by another word.
- - The "Needed to allocate blacklisted ..." warning had inadvertently
- been turned off by default, due to a buggy test in allchblk.c. Turned
- it back on.
- - Removed the marker macros to deal with 2 pointers in interleaved fashion.
- They were messy and the performance improvement seemed minimal. We'll
- leave such scheduling issues to the compiler.
- - Changed Linux/PowerPC test to also check for __powerpc__ in response
- to a discussion on the gcc mailing list.
- - On Matthew Flatt's suggestion removed the "static" from the jmp_buf
- declaration in GC_generic_push_regs. This was causing problems in
- systems that register all of their own roots. It looks far more correct
- to me without the "static" anyway.
- - Fixed several problems with thread local allocation of pointerfree or
- typed objects. The collector was reclaiming thread-local free lists, since
- it wasn't following the link fields.
- - There was apparently a long-standing race condition related to multithreaded
- incremental collection. A collection could be started and a thread stopped
- between the memory unprotect system call and the setting of the
- corresponding dirt bit. I believe this did not affect Solaris or PCR, which
- use a different dirty-bit implementation. Fixed this by installing
- signal handlers with sigaction instead of signal, and disabling the thread
- suspend signal while in the write-protect handler. (It is unclear
- whether this scenario ever actually occurred. I found it while tracking
- down the following:)
- - Incremental collection did not cooperate correctly with the PARALLEL_MARK
- implementation of GC_malloc_many or the local_malloc primitves. It still
- doesn't work well, but it shouldn't lose memory anymore.
- - Integrated some changes from the gcc source tree that I had previously
- missed. (Thanks to Bryce McKinley for the reminder/diff.)
- - Added Makefile.direct as a copy of the default Makefile, which would
- normally be overwritten if configure is run.
- - Changed the gc.tar target in Makefile.direct to embed the version number
- in the gc directory name. This will affect future tar file distributions.
- - Changed the Irix dynamic library finding code to no longer try to
- eliminate writable text segments under Irix6.x, since that is probably no
- longer necessary, and can apparently be unsafe on occasion. (Thanks to
- Shiro Kawai for pointing this out.)
- - GC_cleanup with GC_DEBUG enabled passed a real object base address to
- GC_debug_register_finalizer_ignore_self, which expected a pointer past the
- debug header. Call GC_register_finalizer_ignore_self instead, even with
- debugging enabled. (Thanks to Jean-Daniel Fekete for catching this.)
- - The collector didn't build with call chain saving enabled but NARGS=0.
- (Thanks to Maarten Thibaut.)
- - Fixed up the GNU-style build files enough so that they work in some
- obvious cases.
- - Added initial port to Digital Mars compiler for win32. (Thanks to Walter
- Bright.)
-
-Since 6.0alpha8:
- - added README.macros.
- - Made gc.mak a symbolic link to work around winzip's tendency to ignore
- hard links.
- - Simplified the setting of NEED_FIND_LIMIT in os_dep.c, possibly breaking
- it on untested platforms.
- - Integrated initial GNU HURD port. (Thanks to Chris Lingard and Igor
- Khavkine.)
- - A few more fixes for Digital Mars compiler (Walter Bright).
- - Fixed gcc version recognition. Renamed OPERATOR_NEW_ARRAY to
- GC_OPERATOR_NEW_ARRAY. Changed GC_OPERATOR_NEW_ARRAY to be the default.
- It can be overridden with -DGC_NO_OPERATOR_NEW_ARRAY. (Thanks to
- Cesar Eduardo Barros.)
- - Changed the byte size to free-list mapping in thread local allocation
- so that size 0 allocations are handled correctly.
- - Fixed Linux/MIPS stackbottom for new toolchain. (Thanks to Ryan Murray.)
- - Changed finalization registration to invoke GC_oom_fn when it runs out
- of memory.
- - Removed lvalue cast in finalize.c. This caused some debug configurations
- not to build with some non-gcc compilers.
-
-Since 6.0alpha9:
- - Two more bug fixes for KEEP_BACK_PTRS and DBG_HDRS_ALL.
- - Fixed a stack clearing problem that resulted in SIGILL with a
- misaligned stack pointer for multithreaded SPARC builds.
- - Integrated another HURD patch (thanks to Igor Khavkine).
-
-Since 6.0:
- - Non-debug, atomic allocations could result in bogus smashed object
- reports with debugging on. (Thanks to Patrick Doyle for the small
- test case.)
- - Fixed GC_get_register_stack_base (Itanium only) to work around a glibc
- 2.2.4 bug.
- - Initial port to HP/UX on Itanium. Thread support and both 32 and 64
- bit ABIs appear to work. Parallel mark support doesn't yet, due to
- some inline assembly code issues. Thread local allocation does appear
- to work.
- - ifdef'ed out glibc2.1/Itanium workaround. I suspect nobody is using
- that combination anymore.
- - Added a patch to make new_gc_alloc.h usable with gcc3.0. (Thanks to
- Dimitris Vyzovitis for the patch.)
- - Debugged 64-bit support on HP/UX PA-RISC.
- - Turned on dynamic loading support for FreeBSD/ELF. (Thanks to Peter
- Housel.)
- - Unregistering of finalizers with debugging allocation was broken.
- (Thanks to Jani Kajala for the test case.)
- - Old finalizers were not returned correctly from GC_debug_register_finalizer.
- - Disabled MPROTECT_VDB for Linux/M68K based on a report that it doesn't work.
- - Cleaned up some statistics gathering code in reclaim.c (Thanks to Walter
- Bright.)
- - Added some support for OpenBSD/ELF/Linux. (Thanks to Suzuki Toshiya.)
- - Added Jakub Jelinek's patch to use dl_iterate_phdr for dynamic library
- traversal to dyn_load.c. Changed it to weakly reference dl_iterate_phdr,
- so that the old code is stilll used with old versions of glibc.
- - Cleaned up feature test macros for various threads packages and
- integrated (partially functional) FreeBSD threads code from Loren Rittle.
- It's likely that the cleanup broke something, since it touched lots of
- code. It's also likelly that it fixed some unreported bugs in the
- less common thread implementations, since some of the original code
- didn't stand up to close scrutiny. Support for the next pthreads
- implementation should be easier to add.
-
-Since 6.1alpha1:
- - No longer wrap read by default in multithreaded applications. It was
- pointed out on the libgcj list that this holds the allocation lock for
- way too long if the read blocks. For now, reads into the heap are
- broken with incremental collection. It's possible to turn this back on
- if you make sure that read calls don't block (e.g. by calling select
- first).
- - Fix ifdef in Solaris_threads.h to refer to GC_SOLARIS_THREADS.
- - Added check for environment variable GC_IGNORE_GCJ_INFO.
- - Added printing of stop-the-world GC times if GC_PRINT_STATS environment
- variable is set.
- - The calloc definition in leak_detector.h was missing parentheses, and
- realloc was missing a second argument to GC_REALLOC.
- (Thanks to Elrond (elrond<at>samba-tng.org).)
- - Added GC_PRINT_BACK_HEIGHT environment variable and associated
- code, mostly in the new file backgraph.c. See doc/README.environment.
- - Added -DUSE_GLOBAL_ALLOC to work around a Windows NT issue. (Thanks to
- Jonathan Clark.)
- - Integrated port to NEC EWS4800 (MIPS-based workstation, with somewhat
- different address-space layout). This may help for other machines with
- holes in the data segment. (Thanks to Hironori Sakamoto.)
- - Changed the order in which GC_push_roots and friends push things onto
- the mark stack. GC_push_all calls need to come first, since we can't
- necessarily recovere if those overflow the mark stack. (Thanks to
- Matthew Flatt for tracking down the problem.)
- - Some minor cleanups to mostly support the Intel compiler on Linux/IA64.
-
-Since 6.1 alpha2:
- - Minor cleanup on the gcconfig.h section for SPARC.
- - Minor fix to support Intel compiler for I386/Linux. (Thanks to Sven
- Hartrumpf.)
- - Added SPARC V9 (64-bit) support. (Thanks to Jeff Sturm.)
- - Restructured the way in which we determine whether or not to keep
- call stacks for debug allocation. By default SAVE_CALL_COUNT is
- now zero on all platforms. Added SAVE_CALL_NARGS parameters.
- If possible, use execinfo.h to capture call stack. (This should
- add support for a number of new platforms, though often at
- considerable runtime expense.)
- - Try to print symbolic information for call stacks. On Linux, we
- do this with a combination of execinfo.h and running addr2line in
- a separate process. This is both much more expensive and much more
- useful. Amazingly, it seems to be fast enough for most purposes.
- - Redefined strdup if -DREDIRECT_MALLOC is given.
- - Changed incremental collector and MPROTECT_VDB implementation so that,
- under favorable conditions, pointerfree objects are not protected.
- Added GC_incremental_protection_needs() to determine ahead of time whether
- pointerfree objects may be protected. Replaced GC_write_hint() with
- GC_remove_protection().
- - Added test for GC_ENABLE_INCREMENTAL environment variable.
- - Made GC_time_limit runtime configurable. Added GC_PAUSE_TIME_TARGET
- environment variable.
- - Eliminated GC_page_sz, a duplicate of GC_page_size.
- - Caused the Solaris and Irix thread creation primitives to call
- GC_init_inner().
-
-
-To do:
- - There seem to be outstanding issues on Solaris/X86, possibly with
- finding the data segment starting address. Information/patches would
- be appreciated.
- - Very large root set sizes (> 16 MB or so) could cause the collector
- to abort with an unexpected mark stack overflow. (Thanks again to
- Peter Chubb.) NOT YET FIXED. Workaround is to increase the initial
- size.
- - The SGI version of the collector marks from mmapped pages, even
- if they are not part of dynamic library static data areas. This
- causes performance problems with some SGI libraries that use mmap
- as a bitmap allocator. NOT YET FIXED. It may be possible to turn
- off DYNAMIC_LOADING in the collector as a workaround. It may also
- be possible to conditionally intercept mmap and use GC_exclude_static_roots.
- The real fix is to walk rld data structures, which looks possible.
- - Incremental collector should handle large objects better. Currently,
- it looks like the whole object is treated as dirty if any part of it
- is.
- - Cord/cordprnt.c doesn't build on a few platforms (notably PowerPC), since
- we make some unwarranted assumptions about how varargs are handled. This
- currently makes the cord-aware versions of printf unusable on some platforms.
- Fixing this is unfortunately not trivial.
projects / msp430-gcc.git / blobdiff