add TODO file.
* ChangeLog: add note; append the contents of doc/README.changes.
* doc/README.changes: remove.
* Makefile.direct (DOC_FILES): Remove doc/README.changes.
* doc/doc.am (dist_pkgdata_DATA): Ditto.
* doc/README.contributors: Replace doc/README.changes with ChangeLog.
* Makefile.am (EXTRA_DIST): Add TODO.
* Makefile.direct (DOC_FILES): Ditto.
* Makefile.dj (OTHER_FILES): Ditto.
* Makefile.in: Regenerate.
+Retired in favor of Git commit log. No longer updated.
+
+
2011-07-26 Ivan Maidanski <ivmai@mail.ru>
* tests/realloc_test.c: New file.
* ltmain.sh: Likewise.
* ChangeLog: Created.
-See doc/README.changes for earlier changes.
+-------------------------
+
+Contents of README.changes for earlier changes:
+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.
+
+RECENT UPDATES ARE RECORDED above INSTEAD TO CONFORM TO
+MORE COMMON CONVENTIONS.
+
+
+ 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().
+
+Since 6.1alpha3:
+ - Fixed typo in sparc_mach_dep.S, preventing the 64-bit version from
+ building. Increased 64-bit heap size limit in test.c slightly, since
+ a functional SPARC collector seems to slightly exceed the old limits.
+ (Thanks again to Jeff Sturm.)
+ - Use NPRGREG in solaris_threads.c, thus printing all registers if things
+ go wrong.
+ - Added GC_MARKERS environment variable to allow use of a single marker
+ thread on an MP without confusing the lock implementation.
+ - Collect much less aggressively in incremental mode with GC_TIME_UNLIMITED.
+ This is really a purely generational mode, and we can afford to
+ postpone the collection until the heap is (nearly) full.
+ - Remove read() wrapper for MPROTECT_VDB. It was causing more harm than
+ good. It is often no longer needed if system calls avoid writing to
+ pointerfull heap objects.
+ - Fix MACOSX test in gcconfig.h. (Thanks to John Clements.)
+ - Change GC_test_and_set so that it consistently has one argument.
+ Add spaces to ::: in powerpc assembly code in gc_locks.h.
+ (Thanks to Ryan Murray.)
+ - Fixed a formatting error in dbg_mlc.c. Added prototype to GC_abort()
+ declaration. (Thanks to Michael Smith.)
+ - Removed "source" argument to GC_find_start(). Eliminate GC_FIND_START().
+ - Added win32 recognition code in configure.in. Changed some of the
+ dllimport/export defines in gc.h. (Thanks to Adam Megacz.)
+ - GC_malloc_many didn't set hb_last_reclaimed when it called
+ GC_reclaim_generic. (I'm not sure this matters much, but ...)
+ - Allocating uncollectable objects with debug information sometimes
+ allocated objects that were one byte too small, since uncollectable
+ objects don't have the extra byte added at the end. (Thanks to
+ Wink Saville for pointing this out.)
+ - Added a bit more assertion checking to make sure that gcj objects
+ on free lists never have a nonzero second word.
+ - Replaced BCC_MAKEFILE with an up-to-date one. (Thanks to
+ Andre Leiradella.)
+ - Upgraded libtool, cinfigure.in and some related files to hopefully
+ support NetBSD/SPARC. (Thanks to Adrian Bunk.) Unfortunately,
+ libtool 1.4.2 seemed to be buggy due to missing quotes in several
+ "test" invocations. Fixed those in the ltmain.sh script.
+ - Some win32-specific patches, including the introduction of
+ GC_CreateThread. (Thanks to Adam Megacz.)
+ - Merged in gcj changes from Anthony Green to support embedded systems.
+ - Tried to consistently rename preprocessed assembly files with a capital
+ .S extension.
+ - Use alpha_mach_dep.S on ALPHA again. It doesn't really matter, but this
+ makes our distribution consistent with the gcc one, avoiding future merge
+ problems.
+ - Move GET_MEM definition into gcconfig.h. Include gcconfig.h slightly
+ later in gc_priv.h to avoid forward references to ptr_t.
+ - Add some testing of local allocation to test.c.
+ - Change definition of INVALID_QTID in specific.h. The -1 value was used
+ inconsistently, and too likely to collide with a valid stack address.
+ Some general clean-up of specific.[ch]. Added assertions. (Thanks
+ to Michael Smith for tracking down an intermittent bug to this
+ general area. I'm not sure it has been squashed yet, however.)
+ - On Pthread systems it was not safe to call GC_malloc() between fork()
+ and exec(). According to the applicable standards, it doesn't appear
+ to be safe to call malloc() or many other libc functions either, thus
+ it's not clear this is fixable. Added experimental support for
+ -DHANDLE_FORK in linux_threads.c which tries to support it. It may
+ succeed if libc does the right thing. I'm not sure whether it does.
+ (Thanks to Kenneth Schalk for pointing out this issue.)
+ - Documented thread local allocation primitives to require an
+ explicit GC_init call. GC_init_parallel is no longer declared to
+ be a constructor function, since that isn't portable and often
+ seems to lead to initialization order problems.
+ - Changed gc_cpp.cc and gc_cpp.h in one more attempt to make them
+ compatible with Visual C++ 6. (Thanks to Wink Saville for the
+ patch.)
+ - Some more patches for Linux on HP PA-RISC.
+ - Added include/gc_allocator.h. It implements (hopefully) standard
+ conforming (as opposed to SGI-style) allocators that allocate
+ collectable (gc_allocator) or GC-traceable, but not collectable
+ (traceable_allocator) objects. This borrows heavily from libstc++,
+ which borrows heavily from the SGI implementation, this part of
+ which was written by Matt Austern. Changed test_cpp.cc to very
+ minimally test this.
+ - On Linux/X86, retry mmap with a different start argument. That should
+ allow the collector to use more (closer to 3GB) of the address space.
+ (Thanks to Jeffrey Mark Siskind for tracking this down.)
+ - Force 64 bit alignment with GCJ support. (Reflects Bryce McKinley's
+ patch to the gcc tree.)
+ - Refined the choice of sa_handler vs. sa_sigaction in GC_dirty_init
+ to accomodate some glibc5 systems. (Thanks to Dan Fandrich for the
+ patch.)
+ - Compensated for the fact that current versions of glibc set
+ __libc_stack_end incorrectly on Linux/IA64 while initialization code
+ is running. This could cause the collector to miss 16 bytes of
+ the memory stack if GC_malloc or friends where called before main().
+ - Mostly integrated Takis Psarogiannakopoulos' port to DG/UX Inix 86.
+ This will probably take another iteration to work, since his
+ patch conflicted with the libtool upgrade.
+ - Added README.arm.cross containing some information about cross-
+ compiling to an ARM processor from Margaret Fleck.
+
+Since 6.1alpha4:
+ - Added GC_finalizer_mem_freed, and changed some of the code that
+ decided on heap expansion to look at it. Memory explicitly
+ deallocated by finalizers essentially needs to be counted as reclaimed
+ by the GC. Otherwise there are cases in which the heap can grow
+ unboundedly. (Thanks to Mark Reichert for the test case.)
+ - Integrated Adam Megacz patches to not scan dynamic libraries if
+ we are compiling with gcc on win32. Otherwise we need structured
+ exception handling to deal with asynchronously unmapped root
+ segments, and gcc doesn't directly support that.
+ - Integrated Anthony Green's patch to support Wine.
+ - GC_OPERATOR_NEW_ARRAY was misspelled OPERATOR_NEW_ARRAY in several
+ places, including gc_cpp.cc. (Thanks to Wink Saville for pointing
+ this out.)
+ - Integrated Loren James Rittle's Alpha FreeBSD patches. In
+ response to Richard Henderson's suggestion, these also
+ changed the declarations of symbols like _end on many platforms to
+ that they wouldn't mistakenly be declared as short data symbols.
+ - Integrated changes from the Debian distribution. (Thanks to Ryan Murray
+ for pointing these out.) Fix C++ comments in POWERPC port. Add ARM32
+ incremental GC support. Get rid of USE_GENERIC_PUSH_REGS for alpha/Linux,
+ this time for real. Use va_copy to get rid of cord printf problems
+ (finally).
+ - Close file descriptor used to count cpus. Thanks to Jeff Sturm for
+ pointing out the omission.
+ - Don't just drop gcj free lists in GC_start_reclaim, since that can
+ eventually cause the marker to see a bogus mark descriptor in the
+ dropped objects. The usual symptom was a very intermittent segmentation
+ fault in the marker. This mattered only if one of the GC_gcj_malloc
+ variants was used. (Thanks to Michael Smith, Jeff Sturm, Bryce
+ McKinley and Tom Tromey for helping to track this down.)
+ - Fixed Linux and Solaris/64 SPARC configuration. (Thanks to David Miller,
+ Jeff Sturm, Tom Tromey, and Christian Joensson.)
+ - Fixed a typo in strdup definition. (Thanks to Gerard A Allan.)
+ - Changed Makefile.direct to invoke $(CC) to assemble alpha_mach_dep.S.
+ This is needed on Linux. I'm not sure whether it's better or worse
+ on Tru64.
+ - Changed gc_cpp.h once more to declare operator new and friends only in
+ a Microsoft environment. This may need further fine tuning. (Thanks to
+ Johannes Schmidt for pointing out that the older code breaks on gcc3.0.4.)
+ - Don't ever override strdup if it's already macro defined. (Thanks to
+ Adnan Ali for pointing out the problem.)
+ - Changed gc_cpp.h yet again to also overload placement new. Due to the
+ C++ overloading rules, the other overloaded new operations otherwise hide
+ placement new, which causes many STL uses to break. (Thanks to Reza
+ Shahidi for reporting this, and to Matt Austern for proposing a fix.)
+ - Integrated cygwin pthreads support from Dan Bonachea.
+ - Turn on DYNAMIC_LOADING for NetBSD. (Thanks to Krister Walfridsson.)
+ - Changed printing code to print more complete GC times.
+ - Applied Mark Mitchell's Irix patch to correct some bitrot.
+ - Clarified which object-printing routines in dbg_mlc.c should hold
+ the allocation lock. Restructured the code to allow reasonable object
+ printing with -DREDIRECT_MALLOC.
+ - Fix the Linux mmap code to always start with 0x1000 as the initial hint.
+ Minor patches for 64-bit AIX, particularly to STACKBOTTOM.
+ (Thanks again to Jeffrey Mark Siskind.)
+ - Renamed "SUSPENDED" flag for Solaris threads support to avoid a conflict
+ with a system header. (Thanks to Philp Brown.)
+ - Cause win32_threads.c to handle an out of range stack pointer correctly,
+ though currently with a warning. (Thanks to Jonathan Clark for
+ observing that win32 applications may temporarily use the stack
+ pointer for other purposes, and suggesting a fix. Unfortunately, it's
+ not clear that there is a complete solution to this problem.)
+
+Since 6.1alpha5:
+ - Added GC_MAXIMUM_HEAP_SIZE environment variable.
+ - Fix configure.in for MIPS/LINUX. (Thanks to H.J. Lu.)
+ - Double page hash table size for -DLARGE_CONFIG.
+ - Integrated Bo Thorsen's X86-64 support.
+ - STACKBOTTOM definition for LINUX/MIPS was partially changed back.
+ (Thanks to H.J. Lu and Hiroshi Kawashima for resolving this.)
+ - Replaced all occurrences of LINUX_DATA_START in gcconfig.h with
+ SEARCH_FOR_DATA_START. It doesn't hurt to falll back to a search.
+ And __data_start doesn't seem to get defined correctly of the GC
+ library is loaded with LD_PRELOAD, e.g. for leak detection.
+ - If the GC_find_leak environment variable is set, do a
+ atexit(GC_gcollect) to give us at least one chance to detect leaks.
+ This may report some very benign leaks, but ...
+ - Addeded REDIRECT_FREE. It's necessary if we want leak detection with
+ LD_PRELOAD.
+ - Defer printing of leaked objects, as for smashed objects.
+ - Fixed process and descriptor leak in GC_print_callers. Try for
+ line number even if we got function name.)
+ - Ported parallel GC support and thread local allocation to Alpha.
+ Not yet well-tested.
+ - Added GC_DUMP_REGULARLY and added finalization statistics to GC_dump().
+ - Fixed Makefile.am to mention alpha_mach_dep.S instead of the defunct
+ alpha_mach_dep.s. (Thanks to Fergus Henderson.)
+ - Incorporated a change to new_gc_alloc.h, suggested by Johannes Schmidt,
+ which should make it work with gcc3.1. (I would still like to encourage
+ use of gc_allocator.h instead.)
+ - Use alpha_mach_dep.S only on Linux. (It's not clear that this is
+ optimal, but it otherwise didn't build on Tru64. Thanks to Fergus
+ Henderson.)
+ - Added ifdef to guard free() in os_dep.c. Otherwise we get a
+ compilation error on Irix. (Thanks to Dai Sato.)
+ - Added an experimental version of GC_memalign to mallocx.c. This can't
+ always work, since we don't handle alignment requests in the hblk-level
+ allocator, and we can't handle arbitrary pointer displacements unless
+ GC_all_interior_pointers is enabled. But it should work for alignment
+ requests up to HBLKSIZE. This is not yet documented in the standard
+ places.
+ - Finally debugged the OSF1/Tru64 thread support. This needs more testing,
+ since I needed to add a somewhat unconvincing workaround for signal
+ delivery issues that I don't yet completely understand. But it does
+ pass my tests, even in parallel GC mode. Incremental GC support is
+ disabled if thread support is enabled, due to the signal issues.
+ - Eliminated name-space-incorrect definition of _cdecl from gc_cpp.h.
+ - Added GC_debug_malloc_replacement and GC_debug_realloc_replacement
+ declarations to gc.h. On IA64, this is required for REDIRECT_MALLOC
+ to work correctly with these.
+ - Fixed Linux USE_PROC_FOR_LIBRARIES to work with a 64-bit /proc format.
+
+Since 6.1:
+ - Guard the test for GC_DUMP_REGULARLY in misc.c with
+ "#ifndef NO_DEBUGGING". Otherwise it fails to build with NO_DEBUGGING
+ defined. (Thanks to Manuel Serrano.)
+ - Message about retrying suspend signals was incorrectly generated even when
+ flag was not set.
+ - Cleaned up MACOSX/NEXT root registration code. There was apparently a
+ separate ifdef case in GC_register_data_segments() for no reason.
+ - Removed MPROTECT_VDB for MACOSX port, based on one negative report.
+ - Arrange for gc.h and friends to be correctly installed with GNU-style
+ "make install".
+ - Enable the GNU-style build facility include C++ support in the library
+ with --enable-cplusplus. (Thanks to Thomas Maier for some of the patch.)
+ - Mark from GC_thread_key in linux_threads.c, in case that's allocated
+ from the garbage collected heap, as it is with our own thread-specific
+ storage implementation. (Thanks to Jeff Sturm.)
+ - Mark all free list header blocks if they are heap allocated. This avoids
+ some unnecessary tracing. And it remains correct if we clear the
+ root set. (Thanks to Jeff Sturm for identifying the bug.)
+ - Improved S390/Linux support. Add S390/Linux 64-bit support. (Thanks
+ to Ulrich Weigand.)
+ - Corrected the spelling of GC_{M,C}ALLOC_EXPLICTLY_TYPED to
+ GC_{M,C}ALLOC_EXPLICITLY_TYPED in gc_typed.h. This is technically
+ an interface change. Based on the fact that nobody reported this,
+ I suspect/hope there were no clients.
+ - Cleaned up gc_typed.h so that (1) it adds an extern "C" declaration
+ when appropriate, (2) doesn't generate references to undefined internal
+ macros, and (3) allows easier manual construction of descriptors.
+ - Close the file descriptor used by GC_print_address_map().
+ - Set the "close-on-exec" bit for various file descriptors maintained
+ for the collector's internal use.
+ - Added a hack to find memory segments owned by the system allocator
+ under win32. Based on my tests, this tends to eventually find all
+ segments, though it may take a while. There appear to be cleaner,
+ but slower solutions under NT/XP. But they rely on an API that's
+ unsupported under 9X.
+ - Changed Linux PowerPC stack finding to LINUX_STACKBOTTOM. (Thanks
+ to Akira Tagoh for pointing out that HEURISTIC1 doesn't work on
+ 64-bit kernels.)
+ - Added GC_set_free_space_divisor to avoid some Windows dll issues.
+ - Added FIXUP_POINTER, POINTER_SHIFT, POINTER_MASK to allow preprocessing
+ of candidate pointers for tagging, etc.
+ - Always lock around GC_notify_full_gc(). Simplified code for
+ invoking GC_notify_full_gc().
+ - Changed the way DATASTART is defined on FreeBSD to be robust against
+ an unmapped page after etext. (Thanks to Hironori Sakamoto for
+ tracking down the intermittent failure.)
+ - Made GC_enable() and GC_disable() official. Deprecated direct update
+ of GC_dont_gc. Changed GC_gcollect to be a noop when garbage collection
+ is disabled.
+ - Call GC_register_dynamic_libraries before stopping the world on Linux,
+ in order to avoid a potential deadlock due to the dl_iterate_phdr lock.
+ - Introduced a more general mechanism for platform-dependent code to
+ decide whether the main data segment should be handled separately
+ from dynamic libraries, or registered by GC_register_dynamic_libraries.
+ The latter is more reliable and easier on Linux with dl_iterate_phdr.
+
+Since 6.2alpha1:
+ - Fixed the completely broken FreeBSD code in 6.2alpha1. (Thanks to
+ Hironori Sakamoto for the patch.)
+ - Changed IRIX reference in dbg_mlc.c to IRIX5. (Thanks to Marcus Herbert.)
+ - Attempted to work around the problems with .S filenames and the SGI
+ compiler. (Reported by several people. Untested.)
+ - Worked around an HP/UX make issue with the GNU-style build process.
+ - Fixed the --enable-cplusplus build machinery to allow builds without
+ a C++ compiler. (That was always the intent ...)
+ - Changed the debugging allocation macros to explicitly pass the return
+ address for Linux and XXXBSD on hardware for which we can't get stack
+ traces. Use __builtin_return_address(0) to generate it when possible.
+ Some of the configuration work was cleaned up (good) and moved to gc.h
+ (bad, but necessary). This should make leak detection more useful
+ on a number of platforms. (Thanks to Fabian Thylman for the suggestion.)
+ - Fixed compilation problems in dbg_mlc.c with GC_ADD_CALLER.
+ - Bumped revision number for dynamic library.
+
+Since 6.2alpha2:
+ - Don't include execinfo.h in os_dep.c when it's not needed, and may not exist.
+
+Since 6.2alpha3:
+ - Use LINUX_STACKBOTTOM for >= glibc2.2 on Linux/MIPS. (See Debian bug
+ # 177204)
+ - Integrated Jeff Sturm and Jesse Rosenstock's MACOSX threads patches.
+ - Integrated Grzegorz Jakacki's substantial GNU build patch. "Make dist"
+ should now work for the GNU build process. Documentation files
+ are installed under share/gc.
+ - Tweaked gc_cpp.h to again support the Borland compiler. (Thanks to
+ Rene Girard for pointing out the problems.)
+ - Updated BCC_MAKEFILE (thanks to Rene Girard).
+ - Added GC_ASSERT check for minimum thread stack size.
+ - Added --enable-gc-assertions.
+ - Added some web documentation to the distribution. Updated it in the
+ process.
+ - Separate gc_conf_macros.h from gc.h.
+ - Added generic GC_THREADS client-defined macro to set the appropriate
+ GC_XXX_THREADS internal macro. (gc_config_macros.h.)
+ - Add debugging versions of _ignore_off_page allocation primitves.
+ - Moved declarations of GC_make_closure and GC_debug_invoke_finalizer
+ from gc.h to gc_priv.h.
+ - Reset GC_fail_count even if only a small allocation succeeds.
+ - Integrated Brian Alliet's patch for dynamic library support on Darwin.
+ - gc_cpp.h's gc_cleanup destructor called GC_REGISTER_FINALIZER_IGNORE_SELF
+ when it should have called the lower case version, since it was
+ explicitly computing a base pointer.
+
+Since 6.2alpha4:
+ - GC_invoke_finalizers could, under rare conditions, set
+ GC_finalizer_mem_freed to an essentially random value. This could
+ possibly cause unbounded heap growth for long-running applications
+ under some conditions. (The bug was introduced in 6.1alpha5, and
+ is not in gcc3.3. Thanks to Ben Hutchings for finding it.)
+ - Attempted to sanitize the various DLL macros. GC_USE_DLL disappeared.
+ GC_DLL is used instead. All internal tests are now on GC_DLL.
+ README.macros is now more precise about the intended meaning.
+ - Include DllMain in the multithreaded win32 version only if the
+ collector is actually built as a dll. (Thanks to Mohan Embar for
+ a version of the patch.)
+ - Hide the cygwin threadAttach/Detach functions. They were violating our
+ namespace rules.
+ - Fixed an assertion in GC_check_heap_proc. Added GC_STATIC_ASSERT.
+ (Thanks again to Ben Hutchings.)
+ - Removed some obsolete definitions for Linux/PowerPC in gcconfig.h.
+ - CORD_cat was not rebalancing unbalanced trees in some cases, violating
+ a CORD invariant. Also tweaked the rebalancing rule for
+ CORD_cat_char_star. (Thanks to Alexandr Petrosian for the bug report
+ and patch.)
+ - Added hand-coded structured exception handling support to mark.c.
+ This should enable support of dynamic libraries under win32 with
+ gcc-compiled code. (Thanks to Ranjit Mathew for the patch.)
+ Turned on dynamic library scanning for win32/gcc.
+ - Removed some remnants of read wrapping. (Thanks to Kenneth Schalk.)
+ GC_USE_LD_WRAP ws probably broken in recent versions.
+ - The build could fail on some platforms since gcconfig.h could include
+ declarations mentioning ptr_t, which was not defined, e.g. when if_mach
+ was built. (Thanks to Yann Dirson for pointing this out.) Also
+ cleaned up tests for GC_PRIVATE_H in gcconfig.h a bit.
+ - The GC_LOOP_ON_ABORT environment variable interfered with incremental
+ collection, since the write fault handler was erroneously overridden.
+ Handlers are now set up in the correct order.
+ - It used to be possible to call GC_mark_thread_local_free_lists() while
+ the world was not stopped during an incremental GC. This was not safe.
+ Fortunately, it was also unnecessary. Added GC_world_stopped flag
+ to avoid it. (This caused occasional crashes in GC_set_fl_marks
+ with thread local allocation and incremental GC. This probably happened
+ primarily on old, slow multiprocessors.)
+ - Allowed overriding of MAX_THREADS in win32_threads.c from the build
+ command line. (Patch from Yannis Bres.)
+ - Taught the IA64/linux code to determine the register backing store base from
+ /proc/self/maps after checking the __libc symbol, but before guessing.
+ (__libc symbols are on the endangered list, and the guess is likely to not
+ always be right for 2.6 kernels.) Restructured the code to read and parse
+ /proc/self/maps so it only exists in one place (all platforms).
+ - The -DUSE_PROC_FOR_LIBRARIES code was broken on Linux. It claimed that it
+ also registered the main data segment, but didn't actually do so. (I don't
+ think anyone actually uses this configuration, but ...)
+ - Made another attempt to get --enablecplusplus to do the right thing.
+ Since there are unavoidable problems with C programs linking against a
+ dynamic library that includes C++ code, I separated out the c++ code into
+ libgccpp.
+
+Since 6.2alpha5:
+ - There was an extra underscore in the name of GC_save_registers_in_stack
+ for NetBSD/SPARC. (Thanks to Jaap Boender for the patch.)
+ - Integrated Brian Alliet's patch for Darwin. This restructured the
+ linuxthreads/pthreads support to separate generic pthreads support
+ from more the system-dependent thread-stopping code. I believe this
+ should make it easier to eliminate the code duplication between
+ pthreads platforms in the future. The patch included some other
+ code cleanups.
+ - Integrated Dan Bonachea's patch to support AIX threads. This required
+ substantial manual integration, mostly due to conflicts with other
+ recent threads changes. It may take another iteration to
+ get it to work.
+ - Removed HPUX/PA-RISC support from aix_irix_threads.c. It wasn't used
+ anyway and it cluttered up the code. And anything we can do to migrate
+ towards generic pthreads support is a good thing.
+ - Added a more explicit test for tracing of function arguments to test.c.
+ (Thanks to Dan Grayson.)
+ - Added Akira Tagoh's PowerPC64 patch.
+ - Fixed some bit rot in the Cygwin port. (Thanks to Dan Bonachea for
+ pointing it out.) Gc.h now includes just windows.h, not winbase.h.
+ - Declared GC_save_regs_in_stack() in gc_priv.h. Remove other declarations.
+ - Changed --enable-cplusplus to use automake consitionals. The old way
+ confused libtool. "Make install" didn't work correctly for the old version.
+ Previously --enable-cplusplus was broken on cygwin.
+ - Changed the C version of GC_push_regs to fail at compile time if it is
+ generated with an empty body. This seems to have been the cause of one
+ or two subtle failures on unusual platforms. Those failures should
+ now occur at build time and be easily fixable.
+
+Since 6.2alpha6:
+ - Integrated a second round of Irix/AIX patches from Dan Bonachea.
+ Renamed mips_sgi_mach_dep.S back to mips_sgi_mach_dep.s, since it requires
+ the Irix assembler to do the C preprocessing; gcc -E doesn't work.
+ - Fixed Makefile.direct for DARWIN. (Thanks to Manuel Serrano.)
+ - There was a race between GC_pthread_detach and thread exit that could
+ result in a thread structure being deallocated by GC_pthread_detach
+ eventhough it was still needed by the thread exit code. (Thanks to
+ Dick Porter for the small test case that allowed this to be debugged.)
+ - Fixed version parsing for non-alpha versions in acinclude.m4 and
+ version checking in version.h.
+
+Since 6.2:
+ - Integrated some NetBSD patches forwarded to me by Marc Recht. These
+ were already in the NetBSD package.
+ - GC_pthread_create waited for the semaphore even if pthread_create failed.
+ Thanks to Dick Porter for the pthread_support.c patch. Applied the
+ analogous fix for aix_irix_threads.c.
+ - Added Rainer Orth's Tru64 fixes.
+ - The check for exceeding the thread table size in win32 threadDetach
+ was incorrect. (Thanks to Alexandr Petrosian for the patch.)
+ - Applied Andrew Begel's patch to correct some reentrancy issues
+ with dynamic loading on Darwin.
+ - GC_CreateThread() was neglecting to duplicate the thread handle in
+ the table. (Thanks to Tum Nguyen for the patch.)
+ - Pass +ESdbgasm only on PA-RISC machines with vendor compiler.
+ (Thanks to Roger Sayle for the patch.)
+ - Applied more AIX threads patches from Scott Ananian.
+
+Since 6.3alpha1:
+ - Reenabled I_HOLD_LOCK assertion in aix_irix_threads.h.
+ - Put back the WINABI qualifier for GC_CreateThread. (Thanks to
+ Danny Smith for the patch. 6.3alpha1 had the qualifier in one place
+ but not elsewhere, which was clearly wrong.)
+ - Sometimes explicitly define __private_extern__ before DARWIN dyld.h
+ include. (Thanks to Andreas Tobker for postting the patch.)
+ - Included signal.h from pthread_support.c. Removed GC_looping_handler,
+ which was dead code.
+ - GC_find_start was misdeclared by gc_pmark.h if PRINT_BLACK_LIST was
+ defined. (Thanks to Glauco Masotti for testing and reporting this.)
+ Changed GC_find_start to never just return 0. According to its
+ comment it doesn't, and it's unclear that's correct.
+ - GC_alloc_large had several largely compensating bugs in the
+ computation of GC_words_wasted. (It was confused about bytes vs.
+ words in two places.)
+ - Integrated Slava Sysoltev's patch to support more recent versions of
+ the Intel compiler on IA64/Linux.
+ - Changed win32 spinlock initialization to conditionally set a spin count.
+ (Emmanual Stumpf pointed out that enabling this makes a large performance
+ difference on win32 multiprocessors.) Also cleaned up the win32 spinlock
+ initialization code a bit.
+ - Fixed thread support for HP/UX/IA64. The register backing store base for
+ the main thread was sometimes not set correctly. (Thanks to Laurent
+ Morichetti.)
+ - Added -DEMPTY_GETENV_RESULTS flag to work around Wine problem.
+ - Declare GC_stack_alloc and GC_stack_free in solaris_threads.h to
+ avoid 64-bit size mismatches. (Thanks to Bernie Solomon.)
+ - Fixed GC_generic_push_regs to avoid a potential and very unfortunate
+ tail call optimization. This could lead to prematurely reclaimed
+ objects on configurations that used the generic routine and the new
+ build infrastructure (which potentially optimizes mach_dep.c).
+ This was a serious bug, but it's unclear whether it has resulted in
+ any real failures.
+ - Fixed CORD_str to deal with signed characters. (Thanks to Alexandr
+ Petrosian for noticing the problem and supplying the patch.)
+ - Merged a couple of NOSYS/ECOS tests into os_dep.c from gcj. (Thanks
+ to Anthony Green.)
+ - Partially merged a win32 patch from Ben Hutchings, and substantially
+ revised other parts of win32_threads.c. It had several problems.
+ Under MinGW with a statically linked library, the main thread was
+ not registered. Cygwin detached threads leaked thread descriptors.
+ There were several race conditions. For now, unfortunately the
+ static threads limit remains, though we increased it, and made table
+ traversal cost depend on the actual thread count.
+ There is also still some code duplication with pthread_support.c.
+ (Thread descriptors did become much smaller, since Ben Hutchings
+ removed the thread context from them.)
+ - Integrated a Solaris configure.in patch from Rainer Orth.
+ - Added GC_IGNORE_FB and associated warning to very partially address
+ the issue of the collector treating a mapped frame buffer as part
+ of the root set. (Thanks to David Peroutka for providing some
+ insight. More would be helpful. Is there anything that can be used
+ to at least partially identify such memory segments?)
+
+Since 6.3alpha2:
+ - Removed -DSMALL_CONFIG from BCC_MAKEFILE.
+ - Changed macros to test for an ARM processor (Patch from Richard Earnshaw.)
+ - Mostly applied a DJGPP patch from Doug Kaufman. Especially Makefile.dj
+ had suffered from serious bit rot.
+ - Rewrote GC_apply_to_maps, eliminating an off-by-one subscript error,
+ and a call to alloca (for lcc compatibility).
+ - Changed USE_MUNMAP behavior on posixy platforms to immediately remap
+ the memory with PROT_NONE instead of unmapping it. The latter risks
+ an intervening mmap grabbing the address space out from underneath us.
+ Updated this code to reflect a cleaner patch from Ulrich Drepper.
+ - Replaced _T with _Tp in new_gc_alloc.h to avoid a MACOS X conflict.
+ (Patch from Andrew Begel.)
+ - Dynamically choose whether or not lock should spin on win32. (Thanks
+ to Maurizio Vairani for the patch.) This may be a significant performance
+ improvement for win32.
+ - Fix Makefile.direct to actually include NT_STATIC_THREADS_MAKEFILE
+ in the distribution. (Again thanks to Maurizio Vairani.)
+ - Maybe_install_looping_handler() was accidentally exported, violating
+ our name space convention.
+ - Made os_dep.c use sigsetjmp and SA_NODEFER for NetBSD. (Thanks to
+ Christian Limpach.) (I generalized the patch to use sigsetjmp on all
+ UNIX_LIKE platforms, admittedly a slightly risky move. But it may avoid
+ similar problems on some other platforms. I also cleaned up the defn
+ of UNIX_LIKE a bit. - Hans)
+ - Integrated Andrew Begel's Darwin threads patch, adjusted according to
+ some of Fergus Hendersons's comments. (Patch didn't apply cleanly,
+ errors are possible.)
+ - Added another test or two for the Intel 8.0 compiler to avoid
+ confusing it with gcc. The single-threaded collector should now build
+ with icc, at least on ia64.
+
+Since 6.3alpha3:
+ - USE_MMAP was broken by confusion in the code dealing with USE_MMAP_ANON.
+ (This was pointed out, and fixes were suggested by several other people.)
+ - Darwin supprt was broken in alpha3 as a result of my misintegration of
+ Andrew Begel's patches. Fixed with another patch from Andrew Begel.
+ - A new sanity check in pthread_stop_world.c:GC_push_all_stacks() was
+ overly aggressive. We may collect from an unregistered thread during
+ thread creation. Fixed by explicitly checking for that case. (Added
+ GC_in_thread_creation.)
+
+Since 6.3alpha4:
+ - Fix & vs && typo in GC_generic_malloc and
+ GC_generic_malloc_ignore_off_page. (Propagated from the gcc tree.)
+ - Removed SA_NODEFER hack from NetBSD and Solaris write-protect handler.
+ (According to Christian Limpach, the NetBSD problem is fixed.
+ Presumably so is the Solaris 2.3 problem.)
+ - Removed placement delete from gc_cpp.h for the SGI compiler.
+ (Thanks to Simon Gornall for the patch.)
+ - Changed semantics of the GC_IGNORE_FB environment variable, based
+ on experimentation by Nicolas Cannasse pointing out that the old
+ interpretation was useless. We still need help in identifying win32
+ graphics memory mappings. The current "solution" is a hack.
+ - Removed "MAKEOVERRIDES =" from Makefile.am and thus Makefile.in.
+ It probably made more sense in the gcc context.
+ - Explicitly ensure that NEED_FIND_LIMIT is defined for {Open,Net}BSD/ELF.
+ - Replaced USE_HPUX_TLS macro by USE_COMPILER_TLS, since gcc often
+ supports the same extension on various platforms.
+ - Added some basic (completely untested) defines for win64, in support
+ of future work.
+ - Declared GC_jmp_buf in os_dep.s as JMP_BUF instead of jmp_buf, fixing
+ a memory overwrite bug on Solaris and perhaps other platforms.
+ - Added 0 != __libc_stack_end test to GC_linux_stack_base. (Thanks to Jakub
+ Jelinek, both for the patch, and for explaining the problem to me.)
+ Otherwise "prelink"ing could cause the collector to fail.
+ - Changed default thread local storage implementation to USE_PTHREAD_SPECIFIC
+ for HP/UX with gcc. The compiler-based implementation appears to work
+ only with the vendor compiler.
+ - Export GC_debug_header_size and GC_USR_PTR_FROM_BASE from gc_mark.h,
+ making client mark code cleaner and less dependent on GC version.
+ - Export several new procedures and GC_generic_malloc from gc_mark.h
+ to support user-defined kinds. Use the new procedures to replace existing
+ code in gcj_mlc.c and typd_mlc.c.
+ - Added support for GC_BACKTRACES.
+ - Fixed a remaining problem in CORD_str with signed characters. (Thanks
+ to Alexandr Petrosian for the patch.)
+ - Removed supposedly redundant, but very buggy, definitions of finalizer
+ macros from javaxfc.h. Fortunately this file probably has no users.
+ The correct declarations were already in gc.h.
+ - Also need to set GC_in_thread_creation while waiting for GC during
+ thread termination, since it is also possible to collect from an
+ unregistered thread in that case.
+ - Define NO_GETENV for Windows CE, since getenv doesn't appear to exist.
+ + some other minor WinCE fixes. (Thanks to Alain Novak.)
+ - Added GC_register_describe_type_fn.
+ - Arrange for debugging finalizer registration to ignore non-heap
+ registrations, since the regular version of the routine also behaves
+ that way.
+ - GC_gcj_malloc and friends need to check for finalizers waiting to be run.
+ One of the more obscure allocation routines with missing a LOCK() call.
+ - Fixed cvtres invocations in NT_MAKEFILE and NT_STATIC_THREADS_MAKEFILE
+ to work with VS.NET.
+ - Cleaned up GC_INIT calls in test. Updated gc.man to encourage GC_INIT
+ use in portable code.
+ - Taught the GC to use libunwind if --enable-full-debug is specified on
+ IA64 and libunwind is present.
+ - The USE_MUNMAP code could get confused about the age of a block and
+ prematurely unmap it. GC_unmap_old had a bug related to wrapping of
+ GC_gc_no. GC_freehblk and GC_merge_unmapped didn't maintain
+ hb_last_reclaimed reasonably when blocks were merged. The code was
+ fixed to reflect original intent, but that may not always be an
+ improvement. See todo list item.
+
+Since 6.3alpha5:
+ - Define USE_GENERIC_PUSH_REGS for NetBSD/M68K.
+ - Fixed the X86_64 PREFETCH macros to correctly handle ia32e (which uses
+ different prefetch instructions from AMD64). (Thanks to H.J. Lu.)
+ - GC_config_macros.h did not correctly define GC_WIN32_THREADS from
+ GC_THREADS.
+ - Added simple_example.html.
+ - Merged Andrew Gray's patch to correctly restore signal handlers on
+ FreeBSD.
+ - Merged a patch from Andreas Jaeger to deal with prefetch-related warnings
+ on x86-64. Added some other casts so that the PREFETCH macros
+ always get a ptr_t argument. Removed some casts inthe PREFETCH
+ implementations.
+ - At Jesse Jones suggestion: Added a header guard for gc_allocator.h
+ and changed GC_debug_free to clobber contents of deallocated object.
+ - The signal masking code in pthread_stop_world.c contained some errors.
+ In particular SIGSEGV was masked in the handler, in spite of the fact that
+ it wrote to the heap. This could lead to an uncaught SIGSEGV, which
+ apparently became much more likely in Linux 2.6. Also fixed some
+ typos, and reduced code duplication in the same area.
+ - Remove ltconfig, clean up configure messages for DGUX (thanks to
+ Adrian Bunk for the patches).
+ - Integrated NetBSD/OpenBSD patches from Marc Recht and Matthias Drochner.
+
+Since 6.3alpha6:
+ - Compile test_cpp.cc with CXXCOMPILE instead of COMPILE.
+ - Very large allocations could cause a collector hang. Correct
+ calculation of GC_collect_at_heapsize.
+ - GC_print_hblkfreelist printed some bogus results if USE_MUNMAP
+ was defined.
+ - Include gc_config_macros.h in threadlibs.c.
+ - Correct MacOSX thread stop code. (Thanks to Dick Porter.)
+ - SMALL_OBJ definition was off by one. This could cause crashes
+ at startup. (Thanks to Zoltan Varga for narrowing this down to
+ a trivial test case.)
+ - Integrate Paolo Molara's patch to deal with a race in the Darwin
+ thread stopping code.
+ - Changed X86_64 implementation to use SA_SIGINFO in the MPROTECT_VDB
+ implementation. The old approach appears to have been broken by
+ recent kernels.
+ - Added GC_ATTR_UNUSED to eliminate a warning in gc_allocator.h (Thanks
+ to Andrew Begel.)
+ - Fix GC_task_self declaration in os_dep.c. (Thanks to Andrew Pinski.)
+ - Increase INITIAL_BUF_SZ in os_dep.c for Solaris /proc reads.
+
+Since gc6.3:
+ - Merge gcconfig.h changes from gcc tree.
+ - Unconditionally include gc_priv.h in solaris_pthreads.c, win32_threads.h,
+ aix_irix_threads.c, and solaris_threads.c to get thread definitions.
+ - Start marker threads in GC_thr_init, so that they get started even
+ if no other threads are ever started. (Oddly enough, the parallel
+ collector worked correctly, though not well, with no helper threads.)
+ - Go ahead and split large blocks in GC_allochblk_nth if GC_dont_gc
+ is set. (Thanks to Alexander Petrossian.)
+ - GC_PRINT_BACK_HEIGHT would deadlock with thread support.
+ - Let in_progress_space in backgraph.s grow dynamically.
+ - Fix README.solaris2. The GC_thr_init() hack doesn't work anymore.
+ - Convert GC_finalizer_mem_freed to bytes in allchblk.c.
+ - Add missing declaration for GC_generic_malloc_words_small_inner.
+ Without it, s390x breaks. (Thanks to Ulrich Weigand.)
+ - Applied several MacOSX patches to support older tool chains.
+ (Thanks to Stefan Ring.)
+ - Bug fix for NetBSD/amd64. (Thanks to Marc Recht.) Add NetBSD/sh3
+ support. (Thanks to Uchiyama Yasushi.)
+ - Fixed an uninitialized variable in cordprnt.c. (Thanks to gcc for
+ providing the warning.)
+ - Eliminated some, but not all, gcc -Wall warnings.
+ - Changed some old style casts to reinterpret_cast in new_gc_alloc.h.
+ (Thanks to Dan Grayson.)
+ - GC_extend_size_map shouldn't adjust for GC_all_interior_pointers if
+ GC_DONT_ADD_BYTE_AT_END is set.
+ - Changed some (long) casts to (word) in preparation for win64.
+ (Thanks to Peter Colson.)
+ - Changed "int stack_size" declaration in pthread_support.c to use
+ size_t. (Only mattered with GC_ASSERTIONS enabled.)
+ - Added CRIS (etrax) support. (Thanks to Simon Posnjak and
+ Hans-Peter Nilsson.)
+ - Removed GC_IGNORE_FB frame buffer recognition, and replaced
+ it with a check that the mapping type is MEM_IMAGE.
+ In theory, this should work much better, but it is a high
+ risk change for win32. (Thanks to Ashley Bone for the crucial
+ experimental data behind this, and to Rutger Ovidus for
+ some further experiments.)
+ - GC_allochblk_nth incremented GC_words_wasted by bytes rather than
+ words.
+ - Consider GC_words_wasted in GC_adj_words_allocd only if it is within
+ reason. (A hack to avoid some extremely unlikely scenarios in which
+ we manage to allocate only "wasted" space. 7.0 has a better fix.)
+ - Changed PowerPC GC_clear implementation to use lwsync instead of
+ eieio, since the documentation recommends against eieio, and
+ it seems to be incorrect if the preceding memory op is a load.
+ - Fixed print_block_list to print the correct kind number for
+ STUBBORN. (Thanks to Rutger Ovidus.)
+ - Have configure.in generate an error if it is asked to support
+ pthreads, but doesn't know how to.
+ - Added Kazuhiro Inaoka's patch for Renesas M32R support.
+ - Have the GNU build mechanism link with -ldl. Rename THREADLIBS
+ to THREADDLLIBS to reflect this. (Thanks to Sven Verdoolaege.)
+ - Added Hannes Mehnert's patch for FreeBSD/SPARC support.
+ - Merged some FreeBSD specific patches to threadlibs.c and dyn_load.c.
+ (Thanks tp John Merryweather Cooper.)
+ - Define MPROTECT_VDB on MACOSX only if threads are being used, since the
+ dirty page tracking mechanism uses threads. (This avoids an undefined
+ reference to _GC_darwin_register_mach_handler_thread.)
+ - By popular demand, use __libc symbols only if we are built with
+ USE_LIBC_PRIVATES, which is off by default, and not otherwise documented.
+ - Ignore GC_enable_incremental() requests when KEEP_BACK_PTRS is set.
+ The GC itself will dirty lots of pages in this cases, probably making
+ it counterproductive on all platforms. And the DARWIN port crashes.
+
+Since gc6.4:
+ - Integrated Paolo Molaro's patch to deal with EINTR in sem_wait.
+ - Make GC_approx_sp() write to dummy location to ensure that stack
+ is grown here, when sp looks reasonable, rather than later, when
+ it might look like a bad memory reference. (Problem was never
+ observed that I know of. But on rereading the code it seemed
+ dubious.)
+ - Separate out GC_with_callee_saves_pushed and sometimes call
+ it from GC_suspend_handler in pthread_stop_world.c. Callee-save
+ register values sometimes failed to get traced under HP/UX on
+ PA-RISC. Linux/IA64 had the same problem, though non-stacked
+ callee-save registers seem to be so rarely used there that nobody
+ ever noticed.
+ - Integrated an ancient Darwin powerpc_darwin_machine_dep.s patch
+ from Andreas Tobler, which I had lost.
+ - Fix compare_and_exchange implementation for gcc/IA64 to deal with
+ pickier compiler versions.
+ - Fixed Itanium 32-bit ABI support (HP/UX). In particular, the
+ compare_and_exchange implementation didn't consider that possibility.
+ - Undefine GC_pthread_detach in win32_threads.c. (Thanks to
+ Tagliapietra Tommaso.)
+ - Fixed inclusion of frame.h for NETBSD in os_dep.c.
+ - Applied Dan Bonachea's patch to use mmap on AIX.
+ - Several fixes to resurrect the Irix port on recent OS versions.
+ - Change ALPHA to use LINUX_STACKBOTTOM.
+ - Change SPARC64/LINUX to also use LINUX_STACKBOTTOM. Deal with potential
+ bad values of __libc_stack_end on that platform. (Thanks to David Miller.)
+ - Relax gctest to allow larger heap if ALIGN_DOUBLE isn't set.
+ (Unnecessary in 7.0)
+ - Force a define of __STDC__=0 for the IBM compiler on AIX, so that
+ we get prototypes. (Unnecessary in 7.0)
+ - GC_INIT definition for AIX and CYGWIN referred to DATASTART and DATAEND
+ which are only defined in private include files.
+ - Integrated some small gcconfig.h patches from Dan Bonachea. Also
+ relaxed assertion about FreeBSD stack size in pthread_support.c.
+ - Integrated Andrew Begel's darwin_stop_world.c patch for 64-bit
+ support. This may need additional work.
+ - Avoided potentially infinite recursion in GC_save_callers if
+ the system backtrace calls malloc. The workaround currently requires
+ __thread support if this code is used with threads.
+ - Avoided another similar infinite recursion by conditionally
+ invoking GC_save_callers in alloc.c. (Thanks to Matthias Andree
+ for helping to track down both of these.)
+ - Removed all traces of aix_irix_threads.c. AIX and Irix now use
+ pthread_support.c and pthread_stop_world.c. The old code appeared
+ to be unreliable for AIX, and was not regularly maintained.
+ - On Irix, ignore segments with MA_FETCHOP or MA_NOTCACHED attributed;
+ they're not always safe to read.
+ - Fixed a previously vacuous assertion (diagnosed by the SGI compiler)
+ in GC_remove_from_fl.
+ - Fix stack_size assertion in GC_pthread_create.
+ - Fix assertion in GC_steal_mark_stack.
+
+Since gc6.5:
+ - Fix CPU count detection for Irix and FreeBSD. (Thanks to Dan Bonachea.)
+ - Integrate Dan Bonachea's patch for the IBM XLC compiler on Darwin.
+ - Integrated Andreas Tobler's FreeBSD/PowerPC patch.
+ - Don't access the GC thread structure from the restart handler. It's
+ unsafe, since the handler may run too late. (Thanks to Ben Maurer for
+ tracking this down.)
+ - Applied Christian Thalinger's patch to change comment syntax in
+ alpha_mach_dep.S.
+ - Added test for GC_no_dls in GC_dyld_image_add for DARWIN. (Thanks to
+ Juan Jose Garcia Ripoli).
+ - Use LINUX_STACKBOTTOM for Linux/SH and LINUX/ARM. (Thanks to Sugioka
+ Toshinobu and Christian Thalinger.)
+ - Rewrote GC_parse_map_entry. This assumed a fixed column layout of
+ /proc/self/maps on Linux. This ceased to be true about 2 years ago.
+ The old code is probably quite problemetic with -DREDIRECT_MALLOC. It
+ is also used by default for IA64, though I haven't seen actual failures
+ there.
+ - More consistently define HBLKSIZE to 4096 on 64 bit architectures with
+ 4K pages. (Thanks to Andrew Haley.)
+ - With win32 threads, GC_stop_world needs to acquire GC_write_cs. (Thanks
+ to Ben Hutchings for the observation and patch.)
+ - Move up struct callinfo declaration to make gcc 4.0.2. happy.
+
+Since 6.6:
+ - Add "int" to Solaris "end" and "etext" declaration in gc.h. Declared
+ the symbols with underscores and as arrays, since that's what's actually
+ used. Perhaps this could all just be removed? (Thanks to John Bowman.)
+ - Fixed ARM GC_test_and_set code. (Thanks to Kazu Hirata and Paul Brook.)
+ - Added casts for assignments to hb_last_reclaimed, which truncate the
+ value. Added a cast to GC_adj_words_allocd. Use GetModuleHandleA
+ when retrieving a handle to kernel32.dll under win32. (Thanks to the
+ Visual Prolog developers.)
+ - Added Tandem S-Series support. (Thanks to Craig McDaniel. A modified
+ version of his patch was applied, and hence breakage is probably not
+ his fault.)
+ - Remove spurious gc:: qualifier for operator delete[] in gc_cpp.h.
+ (Thanks to Hanno Boeck.)
+ - Changed a test for LINUX in config_macros.h to one for __linux__.
+ - Add prototypes for GC_finalizer_notifier and GC_thr_init. (Thanks to
+ David Ayers.)
+ - Use ld instead of nonexitent ldz instruction in Darwin FindTopOfStack.
+ (Thanks to Andreas Tobler.)
+ - Add support for Darwin/X86. (Thanks to Geoff Norton and the Mono
+ developers.)
+ - Merge in some recent gcc fixes. Add ppc64 asm code. (Thanks to Bryce
+ McKinley and other gcj developers.)
+ - Scan MEM_PRIVATE sections under Windows ME and predecessors.
+ - Interior pointers with some largish offsets into large objects could
+ be ignored, if GC_all_interior_pointers was set. (Oddly this worked
+ correctly for stack references if it was not set. Otherwise it failed
+ for both stack and heap references.) Thanks to Andrew McKinlay for the
+ critical test case.
+ - Integrated Tatsuya Bizenn's NETBSD threads support, with some
+ untested changes.
+ - Added GC_strdup and friends to make leak detection work correctly
+ for strdup clients. (Thanks to Jon Moore.) Fixed the existing strdup
+ with malloc redirection to handle a null malloc return correctly.
+
+Since gc6.7:
+ - Added some support for Dragonfly BSD. (Thanks to Joerg Sonnenberger and
+ Thomas Klausner.)
+ - Improvements to the HP/UX section of configure.in/configure.ac.
+ (Thanks to Andreas Tobler)
+ - GC_unix_get_mem could neglect to release the malloc lock on Irix, under
+ extremely unlikely circumstances. Thanks to Jean-Baptiste Nivois for
+ some careful code reading.
+ - Added support for kFreeBSD + glibc (Thanks to Petr Salinger)
+ - Fix more MacOS threads memory leaks (Thanks to Allan Hsu)
+ - Added initial Solaris/X86-64 support (Thanks to Rainer Orth)
+
+Since gc6.8:
+ - Fix typo in PREFETCH implementation for X86_64. (Thanks to Peter Wang.)
+ - Fix M68K LINUX port. (Thanks to Debian packagers.)
+ - __GNUC__ was misspelled as __GNUC in new_gc_alloc.h. (Thanks to Peter Wang.)
+ - Integrated Allan Hsu's patch for OS X VM deallocation problems.
+ - Applied FreeBSD/X86_64 patch.
+
+Since gc6.9:
+ - Remove GC_PROTO, VOLATILE, GC_PTR, and GC_CONST. Assume ANSI C compiler
+ and use ANSI constructs unconditionally.
+ - Introduce #elif and #error in some of the appropriate places.
+ - Remove GC_printf cruft. Use stdargs.
+ - Remove separate Solaris threads support. Use the more generic Posix
+ implementation.
+ - Use atomic_ops for atomic operations and memory barriers.
+ - Clean up MPROTECT_VDB implementation. Use SA_SIGINFO wherever
+ possible.
+ - Remove broken SIGNALS stuff.
+ - Use size_t instead of word, where appropriate.
+ - Add .S.o rule to Makefile.am.
+ - Officially unsupport SunOS4, several old flavors of M68K (SunOS4,
+ A/UX, HP), IBM PC/RTs and RISCOS/Irix4. (I doubt the old code worked.
+ If anyone cares, these should be easy to resurrect.)
+ - Add EXPECT() in some critical places.
+ - Redefined hb_sz and hb_body to deal with bytes rather than words.
+ This affected a great deal of code. I would like to consistently use
+ byte offsets and sizes where there's not a convincing reason to do
+ otherwise.
+ - Redefined several other variables (GC_mem_found, GC_words_allocd)
+ etc. to use units of bytes. Most of these were also renamed to
+ reflect that fact.
+ - Killed as many "register" declarations as possible.
+ - Partially replaced stubborn allocation with manual write barrier.
+ It's currently broken.
+ - Restructured mark code, to allow mark bits to be kept either on
+ a per allocation granule or per object basis. The emphasis is
+ now on the -DUSE_MARK_BYTES option, since individual bits perform
+ quite badly on hyperthreaded P4s, and are probably suboptimal on
+ other architectures. -DUSE_MARK_BITS is currently broken, and may
+ be resurrected only for the single-threaded case. This significantly
+ reduced the cache footprint required by auxiliary GC data structures.
+ It also reduces space overhead for small heaps. It probably slows
+ things down slightly if interior pointers are very common.
+ - As part of the above, we now maintain an approximate count of set
+ mark bits in each heap block.
+ - As part of the above, the semantics of hb_map changed drastically.
+ For MARK_BIT_PER_OBJ, it doesn't exist. For MARK_BIT_PER_GRANULE,
+ it is purely a way to replace a mod instruction with a table lookup.
+ (Somewhat to my surprise, this still wins on modern hardware.)
+ - Removed PRINTSTATS, GATHERSTATS, and SILENT macros. Everything is
+ now controlled by GC_print_stats variable and GC_PRINT_STATS
+ and new GC_PRINT_VERBOSE_STATS environment variables.
+ - Add GC_log_printf and use it consistently for logging output.
+ - Unconditionally count the objects we reclaim in the sweep phase.
+ For thread local allocation, we need that anyway, and we expect
+ that's increasingly the only case that matters. And it simplifies
+ the code. In general expect minor performance hacks that benefit
+ only the single-threaded case to disappear.
+ - Remove GC_quiet from gc.h and elsewhere.
+ - Changed the heap expansion heuristic, and the definition of
+ GC_free_space_divisor, to refer to live data size, instead of total
+ heap size. I believe this is much more robust. It wasn't previously
+ possible, because we didn't have access to live data size.
+ - Thread local allocation added the extra byte in twice: Once in
+ thread_local_alloc, and once in malloc_many.
+ - Removed GC_malloc_words_small and GC_gcj_fast_malloc. A new
+ mechanism based on the thread local allocation data structures
+ is expected to be added instead. This should allow inlined code
+ that is both fast and doesn't rely on collector internals.
+ - Changed both free lists and reclaim lists to be indexed by granules
+ instead of words, norming halving their size.
+ - MERGE_SIZE is now the only option, and the macro was removed.
+ (Without it, we need a memory reference to GC_all_interior_pointers
+ anyway. Thus it costs us nothing.)
+ - Change GC_size_map to map to granules instead of words. Make sure
+ that every possible size up to TINY_FREELISTS is present.
+ - Split of macros need for fast inline allocation into gc_tiny_fl.h
+ in anticipation of a new inline allocator that doesn't rely on GC
+ internals.
+ - Changed thread local allocation to use GRANULE_BYTES and TINY_FREELISTS
+ in anticipation of a merge with the inline allocation code.
+ - Removed ALIGN_DOUBLE. This is mostly handled by GRANULE_BYTES.
+ - Make locking on most platforms conditional on GC_need_to_lock.
+
+Since gc7.0alpha1:
+ - GC_bytes_allocd was incremented by a possibly uninitialized variable
+ in GC_generic_malloc_inner. (Bug introduced in gc7.0alpha1. Thanks
+ to Ben Hutchings for tracking it down.)
+ - Win32 fixes. (Thanks to Ben Hutchings and Maurizio Vairani.)
+ - Integrated Ben Hutchings' GetWriteWatch-based virtual dirty bit
+ implementation for win32.
+ - Removed pc_gc.tar and floppy targets in Makefile.direct. Removed
+ pc_excludes file.
+ - No longer include GC_bytes_wasted when evaluating allocation progress.
+ Since we are now counting live memory, it no longer makes sense.
+ - Applied Davide Angelocola's configury patch. There are now separate
+ Makefile.am's in the cord and tests subdirectory, more tests, etc.
+ - Renamed configure.in to configure.ac.
+ - Merged a very small number of Nathanael Nerode's configure.ac
+ cleanups from the gcc tree. Unfortunately, that file is a bit
+ different from ours.
+ - Changed EINTR handling in sem_wait slightly.
+ - Restructure the root marking code. Remove all traces of
+ USE_GENERIC_PUSH_REGS, and effectively make it the default.
+ Make it easier to pass a context pointer to the mark routine, in
+ case we ever want to do precise stack marking.
+ - Replace GC_start_blocking() and GC_end_blocking() with GC_do_blocking().
+ This remains undocumented, and only implemented for pthreads. But it
+ removes an otherwise unavoidable race with stores of callee-save
+ registers.
+ - Fix GC_n_mark_bits for the default MARK_BIT_PER_GRANULE case. This
+ resulted in bogus complaints in heap dumps.
+ - Upgrade to libatomic_ops-1.0, and update build structure to match.
+ - Remove SRC_M3 support. Clean up lock initialization code in misc.c.
+ - Removed gc_local_alloc.h. If THREAD_LOCAL_ALLOC is defined, the
+ thread local allocation routines are now called automatically.
+ - Renamed gc_inl.h back to gc_inline.h. Changed the interface appreciably
+ since locking has turned into a dominant issue, and in-line allocation
+ only makes sense if it's no worse than thread-local allocation.
+ Gc_inline.h is now also used to implement thread-local allocation.
+ - Finished replacing stubborn allocation with manual write barrier.
+ Untested.
+ - Use thread-local allocation code by default.
+ - Added GC_register_my_thread and friends for Posix and win32.
+ - Patch for GWW_VDB from Ben Hutchings.
+ - Removed explicit THREAD_LOCAL_ALLOC tests, since that now always
+ redefines GC_malloc.
+ - Removed now unused AIX memory allocation code.
+ - Various minor fixes for bugs introduced in 7.0alpha1.
+
+Since gc7.0alpha2:
+ - Added support for dlopen-based interception of pthread functions.
+ This is only half done. The gc.h redefinitions currently interfere.
+ - Integrated major automake overhaul from Petter Urkedal.
+
+Since gc7.0alpha3:
+ (various 6.5, 6.6 changes)
+ - Removed GC_brief_async_signal_safe_sleep and used atomic_ops instead.
+ (Thanks to Ben Maurer.)
+ - Integrated build patches from David Angelocola and Petter Urkedal.
+ - Fix dynamic-linker-based pthread call redirection.
+ - Renamed RS6000 to POWERPC/AIX.
+ - Allow recovery from SIGSEGV in marker on Linux. This works around
+ a race in thread stack marking if /proc is used to find roots. We do
+ that by default with malloc redirection and threads. This involved
+ moving some GC_find_limit and SETJMP related declarations to gc_priv.h.
+ - Added doc/porting.html file.
+ - Added ADD_HEAP_GUARD_PAGES for sbrk/*nix platforms to debug extreme
+ memory overwrite errors.
+ - Added trivial NO_INCREMENTAL flag to facilitate debugging.
+ - Added GC_getattr_np-based GC_get_stack_base (untested).
+ - Separated thread local allocation into a separate file and added the
+ beginning of win32 support for that.
+
+Since gc7.0alpha4:
+ (more 6.6, 6.7 changes)
+ - Some Solaris fixes, including some more general changes in how
+ the assembly pieces of mach_dep.c are handled.
+ - Removed a lot of SOLARIS_THREADS-specific code that was only
+ needed with the old implementation. This included many (mostly no-op)
+ versions of GC_is_fresh.
+ - Don't use atomic_ops in gc_locks.h unless we need threads.
+ - Fixed USE_MARK_BITS, which is once againthe default without PARALLEL_MARK.
+ - Removed Solaris GC_INIT hack. It's a workaround for a long dead bug,
+ and it seemed to be wrong anyway.
+ - Changed win32_threads.c to require preprocessor-based interception
+ of thread routines by default. A client call to GC_use_DllMain is
+ now required to get the old behavior in which DllMain is used to implicitly
+ register threads. This was doen for uniformity with other platforms, and
+ because the DllMain solution seemed to require very tricky code which,
+ at least in the past, imposed hard bounds onthe number of threads.
+ - Many small changes to make thread support work again on Cygwin.
+ - Moved definition of allocator lock etc. to pthread_support.c and
+ win32_threads.c for those two cases.
+ - Got rid of the FASTLOCK() machinery. It doesn't seem useful on modern
+ platforms.
+ - Cleaned up the uncollectable allocation routines, speeding up the
+ slower paths. The code did enough unnecessary work off the critical path
+ that the underlying logic was getting hard to extract.
+ - No longer turn off THREAD_LOCAL_ALLOC with DBG_HDRS_ALL. Indications
+ are it just works, and I think the reasons for it not working disappeared
+ a while ago.
+ - Fixed bugs in hb_n_marks calculation and assertion.
+ - Don't use __builtin_expect for pre-3.0 gcc.
+ - Define GWW_VDB only for recent Microsoft tool chains.
+ - Add overview.html to doc directory.
+ - Fix NT_STATIC_THREADS_MAKEFILE, various compiler warnings.
+ - Made thread local allocation sort of work with Cygwin. The code should
+ be there to deal with other Windows variants, But non-Cygwin Windows
+ threads need more bug fixes.
+
+Since gc7.0alpha5:
+ (more 6.7 changes)
+ - Declare GC_dump() in gc.h.
+ - Add --enable-large-config, which just defines the LARGE_CONFIG macro.
+ - Make GlobalAlloc address alignment a bit more intuitive. (Thanks to
+ Charles Mills.)
+ - Use #elif in the definitions of GET_MEM.
+ - Overhaul porting.html. Remove corresponding text from README.
+ - Fix typo in DARWIN section of gcconfig.h.
+ - Fix Darwin thread memory leak. (Thanks to Bruce Mitchener.)
+ - Update x86 AO_test_and_set implementation to use "=q".
+ - Add $(EXEEXT) to many tests in tests/tests.am. (Corresponds to a
+ 6.7 fix, which no longer applied.)
+ - Fix Darwin/PPC port.
+ - Fix Cygwin/threads port.
+ - Fix gcj malloc support.
+ - For GNU-style make, don't build libatomic_ops unless threads are requested.
+ This should allow single-threaded builds on platforms which do not
+ currently support libatomic_ops.
+ - Clean up and hopefully fix the CFLAGS calculation for GNU build.
+ (Substantially improves things on HP/UX.)
+ - Integrated Andrei Polushin's Visual C++ patches. These provide for
+ stack traces, better C++ debug support, and better log file handling.
+ Note that these change the location of the log file to a the path of the
+ executable with a .log extension. To get the old behavior back, define
+ OLD_WIN32_LOG_FILE. For the time being, I'm checking his project
+ files and the like into a windows-untested subdirectory. They
+ are almost certainly already out of date, but better than what we had
+ before.
+ - Fixed some win32 threads bugs, and added support for _beginthreadex.
+ - Fix zero size thread local allocation so that explicit deallocation
+ works correctly.
+ - Removed serious bug in GC_malloc_uncollectable(large size).
+ - Do not try to do thread-local gcj allocation in incremental mode. There
+ are races in setting up the descriptor.
+ - Add GC_INIT() to middle.c, fix some more GC_printfn calls.
+ - Some assertions erroneously used I_HOLD_LOCK() negatively, eventhough
+ it can now spuriously return TRUE.
+ - Rename SUNOS5 macro and OS name to SOLARIS and SUNOS5DL to SOLARISDL.
+ - On Linux and some Un*x variants, allocate memory by first trying sbrk,
+ and then switching to mmap if that fails.
+ - Fixed /proc/x/maps reading to deal with asynchronous deletions.
+ - Fix REDIRECT_MALLOC with threads on Linux. It now usually seems to work
+ with ugly hacks that include having calloc behave differently when it is
+ called from ld.so or the pthreads library. A reasonable amount of
+ infrastructure was added to support some of this. Thanks to Roland McGrath
+ for ideas and information.
+ - Import various updated build scripts.
+ - Add GC_register_has_static_roots_callback. (Thanks to Andrew Haley.)
+ - Fix serious bugs in GC_malloc_atomic_uncollectable().
+ - Return GC_SUCCESS form GC_get_stack_base().
+ - Fix several atomic_ops problems on IA64 with HP Compiler.
+ - Update to atomic_ops-1.2.
+ - Fix hb_n_marks description and reclaim.c assertion.
+ - Various additional win32 threads fixes.
+ - Enable GC_ASSERTIONS for Debug build with NT_THREADS_MAKEFILE.
+
+[gc7.0alpha7 was released and version bumped to gc7.0alpha8]
+
+Since first gc7.0alpha8 version:
+ [ Some gc6.9 changes ]
+ - Change FindTopOfStack decl in darwin_stop_world.c.
+ - Move some static tests from misc.c to gcconfig.h. Use #error.
+ - Add GC_print_free_list() function. (Thanks to Bruce Hoult.)
+ - Add GC_GNU_THREADS support on HURD. (Thanks to Aleksey Demakov,
+ Barry DeFreese, and possibly other Debian maintainers.)
+ - __GNUC__ was misspelled as __GNUC in thread_local_alloc.h.
+ (Thanks to Peter Wang.)
+ - Integrated various MacOSX patches and tried to reconcile them.
+ Thanks to Allan Hsu, several contributers at Apple, and probably
+ others.
+ - Added some casts to powerpc.h in libatomic_ops to silence warnings.
+
+To do (OLD):
+ - REDIRECT_MALLOC and threads combination should work on more platforms,
+ and needs more testing on Linux.
+ - Clone marker inner loop to support arch-dependent prefetching,
+ and counting of objects marked for finalization.
+ - The USE_MUNMAP code should really use a separate data structure
+ indexed by physical page to keep track of time since last use of
+ a page. Using hblk headers means we lose track of ages when
+ blocks are merged, and we can't unmap pages that have been allocated and
+ dropped by the blacklisting code. I suspect both of these matter.
+ - A dynamic libgc.so references dlopen unconditionally, but doesn't link
+ against libdl.
+ - GC_proc_fd for Solaris is not correctly updated in response to a
+ fork() call. Thus incremental collection in the child won't work
+ correctly. (Thanks to Ben Cottrell for pointing this out.)
+ - --enable-redirect-malloc is mostly untested and known not to work
+ on some platforms.
+ - 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.
# documentation which is not installed
#
-EXTRA_DIST += README.QUICK
+EXTRA_DIST += README.QUICK TODO
# other makefiles
# :GOTCHA: deliberately we do not include 'Makefile'
include/private/darwin_stop_world.h include/private/thread_local_alloc.h \
$(CORD_SRCS)
-DOC_FILES= README.QUICK doc/README.Mac doc/README.MacOSX doc/README.OS2 \
+DOC_FILES= README.QUICK TODO doc/README.Mac doc/README.MacOSX doc/README.OS2 \
doc/README.amiga doc/README.cords doc/debugging.html \
doc/porting.html doc/overview.html \
doc/README.dj doc/README.hp doc/README.linux doc/README.rs6000 \
doc/README.sgi doc/README.solaris2 doc/README.uts \
doc/README.win32 doc/barrett_diagram doc/README \
- doc/README.contributors doc/README.changes doc/gc.man \
+ doc/README.contributors doc/gc.man \
doc/README.environment doc/tree.html doc/gcdescr.html \
doc/README.autoconf doc/README.macros doc/README.ews4800 \
doc/README.DGUX386 doc/README.arm.cross doc/leak.html \
OTHER_FILES= Makefile PCR-Makefile OS2_MAKEFILE NT_MAKEFILE BCC_MAKEFILE \
README tests/test.c test_cpp.cc extra/setjmp_t.c SMakefile.amiga \
SCoptions.amiga README.amiga README.win32 cord/README \
- README.rs6000 README.QUICK callprocs pc_excludes \
+ README.rs6000 README.QUICK TODO callprocs pc_excludes \
barrett_diagram README.OS2 README.Mac MacProjects.sit.hqx \
extra/MacOS.c EMX_MAKEFILE README.debugging \
Mac_files/datastart.c Mac_files/dataend.c \
# The libatomic_ops library. This is not ideal, since we pick up junk from
# there.
-EXTRA_DIST = gc_cpp.cpp README.QUICK BCC_MAKEFILE NT_MAKEFILE \
+EXTRA_DIST = gc_cpp.cpp README.QUICK TODO BCC_MAKEFILE NT_MAKEFILE \
OS2_MAKEFILE PCR-Makefile digimars.mak EMX_MAKEFILE \
Makefile.direct Makefile.dj Makefile.DLLs SMakefile.amiga \
WCC_MAKEFILE autogen.sh build_atomic_ops.sh \
doc/README.amiga \
doc/README.arm.cross \
doc/README.autoconf \
- doc/README.changes \
doc/README.cmake \
doc/README.contributors \
doc/README.cords \
--- /dev/null
+TODO tasks
+==========
+++ /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.
-
-RECENT UPDATES ARE RECORDED IN ../ChangeLog FILE INSTEAD TO CONFORM TO
-MORE COMMON CONVENTIONS.
-
--------------------------
-
- 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().
-
-Since 6.1alpha3:
- - Fixed typo in sparc_mach_dep.S, preventing the 64-bit version from
- building. Increased 64-bit heap size limit in test.c slightly, since
- a functional SPARC collector seems to slightly exceed the old limits.
- (Thanks again to Jeff Sturm.)
- - Use NPRGREG in solaris_threads.c, thus printing all registers if things
- go wrong.
- - Added GC_MARKERS environment variable to allow use of a single marker
- thread on an MP without confusing the lock implementation.
- - Collect much less aggressively in incremental mode with GC_TIME_UNLIMITED.
- This is really a purely generational mode, and we can afford to
- postpone the collection until the heap is (nearly) full.
- - Remove read() wrapper for MPROTECT_VDB. It was causing more harm than
- good. It is often no longer needed if system calls avoid writing to
- pointerfull heap objects.
- - Fix MACOSX test in gcconfig.h. (Thanks to John Clements.)
- - Change GC_test_and_set so that it consistently has one argument.
- Add spaces to ::: in powerpc assembly code in gc_locks.h.
- (Thanks to Ryan Murray.)
- - Fixed a formatting error in dbg_mlc.c. Added prototype to GC_abort()
- declaration. (Thanks to Michael Smith.)
- - Removed "source" argument to GC_find_start(). Eliminate GC_FIND_START().
- - Added win32 recognition code in configure.in. Changed some of the
- dllimport/export defines in gc.h. (Thanks to Adam Megacz.)
- - GC_malloc_many didn't set hb_last_reclaimed when it called
- GC_reclaim_generic. (I'm not sure this matters much, but ...)
- - Allocating uncollectable objects with debug information sometimes
- allocated objects that were one byte too small, since uncollectable
- objects don't have the extra byte added at the end. (Thanks to
- Wink Saville for pointing this out.)
- - Added a bit more assertion checking to make sure that gcj objects
- on free lists never have a nonzero second word.
- - Replaced BCC_MAKEFILE with an up-to-date one. (Thanks to
- Andre Leiradella.)
- - Upgraded libtool, cinfigure.in and some related files to hopefully
- support NetBSD/SPARC. (Thanks to Adrian Bunk.) Unfortunately,
- libtool 1.4.2 seemed to be buggy due to missing quotes in several
- "test" invocations. Fixed those in the ltmain.sh script.
- - Some win32-specific patches, including the introduction of
- GC_CreateThread. (Thanks to Adam Megacz.)
- - Merged in gcj changes from Anthony Green to support embedded systems.
- - Tried to consistently rename preprocessed assembly files with a capital
- .S extension.
- - Use alpha_mach_dep.S on ALPHA again. It doesn't really matter, but this
- makes our distribution consistent with the gcc one, avoiding future merge
- problems.
- - Move GET_MEM definition into gcconfig.h. Include gcconfig.h slightly
- later in gc_priv.h to avoid forward references to ptr_t.
- - Add some testing of local allocation to test.c.
- - Change definition of INVALID_QTID in specific.h. The -1 value was used
- inconsistently, and too likely to collide with a valid stack address.
- Some general clean-up of specific.[ch]. Added assertions. (Thanks
- to Michael Smith for tracking down an intermittent bug to this
- general area. I'm not sure it has been squashed yet, however.)
- - On Pthread systems it was not safe to call GC_malloc() between fork()
- and exec(). According to the applicable standards, it doesn't appear
- to be safe to call malloc() or many other libc functions either, thus
- it's not clear this is fixable. Added experimental support for
- -DHANDLE_FORK in linux_threads.c which tries to support it. It may
- succeed if libc does the right thing. I'm not sure whether it does.
- (Thanks to Kenneth Schalk for pointing out this issue.)
- - Documented thread local allocation primitives to require an
- explicit GC_init call. GC_init_parallel is no longer declared to
- be a constructor function, since that isn't portable and often
- seems to lead to initialization order problems.
- - Changed gc_cpp.cc and gc_cpp.h in one more attempt to make them
- compatible with Visual C++ 6. (Thanks to Wink Saville for the
- patch.)
- - Some more patches for Linux on HP PA-RISC.
- - Added include/gc_allocator.h. It implements (hopefully) standard
- conforming (as opposed to SGI-style) allocators that allocate
- collectable (gc_allocator) or GC-traceable, but not collectable
- (traceable_allocator) objects. This borrows heavily from libstc++,
- which borrows heavily from the SGI implementation, this part of
- which was written by Matt Austern. Changed test_cpp.cc to very
- minimally test this.
- - On Linux/X86, retry mmap with a different start argument. That should
- allow the collector to use more (closer to 3GB) of the address space.
- (Thanks to Jeffrey Mark Siskind for tracking this down.)
- - Force 64 bit alignment with GCJ support. (Reflects Bryce McKinley's
- patch to the gcc tree.)
- - Refined the choice of sa_handler vs. sa_sigaction in GC_dirty_init
- to accomodate some glibc5 systems. (Thanks to Dan Fandrich for the
- patch.)
- - Compensated for the fact that current versions of glibc set
- __libc_stack_end incorrectly on Linux/IA64 while initialization code
- is running. This could cause the collector to miss 16 bytes of
- the memory stack if GC_malloc or friends where called before main().
- - Mostly integrated Takis Psarogiannakopoulos' port to DG/UX Inix 86.
- This will probably take another iteration to work, since his
- patch conflicted with the libtool upgrade.
- - Added README.arm.cross containing some information about cross-
- compiling to an ARM processor from Margaret Fleck.
-
-Since 6.1alpha4:
- - Added GC_finalizer_mem_freed, and changed some of the code that
- decided on heap expansion to look at it. Memory explicitly
- deallocated by finalizers essentially needs to be counted as reclaimed
- by the GC. Otherwise there are cases in which the heap can grow
- unboundedly. (Thanks to Mark Reichert for the test case.)
- - Integrated Adam Megacz patches to not scan dynamic libraries if
- we are compiling with gcc on win32. Otherwise we need structured
- exception handling to deal with asynchronously unmapped root
- segments, and gcc doesn't directly support that.
- - Integrated Anthony Green's patch to support Wine.
- - GC_OPERATOR_NEW_ARRAY was misspelled OPERATOR_NEW_ARRAY in several
- places, including gc_cpp.cc. (Thanks to Wink Saville for pointing
- this out.)
- - Integrated Loren James Rittle's Alpha FreeBSD patches. In
- response to Richard Henderson's suggestion, these also
- changed the declarations of symbols like _end on many platforms to
- that they wouldn't mistakenly be declared as short data symbols.
- - Integrated changes from the Debian distribution. (Thanks to Ryan Murray
- for pointing these out.) Fix C++ comments in POWERPC port. Add ARM32
- incremental GC support. Get rid of USE_GENERIC_PUSH_REGS for alpha/Linux,
- this time for real. Use va_copy to get rid of cord printf problems
- (finally).
- - Close file descriptor used to count cpus. Thanks to Jeff Sturm for
- pointing out the omission.
- - Don't just drop gcj free lists in GC_start_reclaim, since that can
- eventually cause the marker to see a bogus mark descriptor in the
- dropped objects. The usual symptom was a very intermittent segmentation
- fault in the marker. This mattered only if one of the GC_gcj_malloc
- variants was used. (Thanks to Michael Smith, Jeff Sturm, Bryce
- McKinley and Tom Tromey for helping to track this down.)
- - Fixed Linux and Solaris/64 SPARC configuration. (Thanks to David Miller,
- Jeff Sturm, Tom Tromey, and Christian Joensson.)
- - Fixed a typo in strdup definition. (Thanks to Gerard A Allan.)
- - Changed Makefile.direct to invoke $(CC) to assemble alpha_mach_dep.S.
- This is needed on Linux. I'm not sure whether it's better or worse
- on Tru64.
- - Changed gc_cpp.h once more to declare operator new and friends only in
- a Microsoft environment. This may need further fine tuning. (Thanks to
- Johannes Schmidt for pointing out that the older code breaks on gcc3.0.4.)
- - Don't ever override strdup if it's already macro defined. (Thanks to
- Adnan Ali for pointing out the problem.)
- - Changed gc_cpp.h yet again to also overload placement new. Due to the
- C++ overloading rules, the other overloaded new operations otherwise hide
- placement new, which causes many STL uses to break. (Thanks to Reza
- Shahidi for reporting this, and to Matt Austern for proposing a fix.)
- - Integrated cygwin pthreads support from Dan Bonachea.
- - Turn on DYNAMIC_LOADING for NetBSD. (Thanks to Krister Walfridsson.)
- - Changed printing code to print more complete GC times.
- - Applied Mark Mitchell's Irix patch to correct some bitrot.
- - Clarified which object-printing routines in dbg_mlc.c should hold
- the allocation lock. Restructured the code to allow reasonable object
- printing with -DREDIRECT_MALLOC.
- - Fix the Linux mmap code to always start with 0x1000 as the initial hint.
- Minor patches for 64-bit AIX, particularly to STACKBOTTOM.
- (Thanks again to Jeffrey Mark Siskind.)
- - Renamed "SUSPENDED" flag for Solaris threads support to avoid a conflict
- with a system header. (Thanks to Philp Brown.)
- - Cause win32_threads.c to handle an out of range stack pointer correctly,
- though currently with a warning. (Thanks to Jonathan Clark for
- observing that win32 applications may temporarily use the stack
- pointer for other purposes, and suggesting a fix. Unfortunately, it's
- not clear that there is a complete solution to this problem.)
-
-Since 6.1alpha5:
- - Added GC_MAXIMUM_HEAP_SIZE environment variable.
- - Fix configure.in for MIPS/LINUX. (Thanks to H.J. Lu.)
- - Double page hash table size for -DLARGE_CONFIG.
- - Integrated Bo Thorsen's X86-64 support.
- - STACKBOTTOM definition for LINUX/MIPS was partially changed back.
- (Thanks to H.J. Lu and Hiroshi Kawashima for resolving this.)
- - Replaced all occurrences of LINUX_DATA_START in gcconfig.h with
- SEARCH_FOR_DATA_START. It doesn't hurt to falll back to a search.
- And __data_start doesn't seem to get defined correctly of the GC
- library is loaded with LD_PRELOAD, e.g. for leak detection.
- - If the GC_find_leak environment variable is set, do a
- atexit(GC_gcollect) to give us at least one chance to detect leaks.
- This may report some very benign leaks, but ...
- - Addeded REDIRECT_FREE. It's necessary if we want leak detection with
- LD_PRELOAD.
- - Defer printing of leaked objects, as for smashed objects.
- - Fixed process and descriptor leak in GC_print_callers. Try for
- line number even if we got function name.)
- - Ported parallel GC support and thread local allocation to Alpha.
- Not yet well-tested.
- - Added GC_DUMP_REGULARLY and added finalization statistics to GC_dump().
- - Fixed Makefile.am to mention alpha_mach_dep.S instead of the defunct
- alpha_mach_dep.s. (Thanks to Fergus Henderson.)
- - Incorporated a change to new_gc_alloc.h, suggested by Johannes Schmidt,
- which should make it work with gcc3.1. (I would still like to encourage
- use of gc_allocator.h instead.)
- - Use alpha_mach_dep.S only on Linux. (It's not clear that this is
- optimal, but it otherwise didn't build on Tru64. Thanks to Fergus
- Henderson.)
- - Added ifdef to guard free() in os_dep.c. Otherwise we get a
- compilation error on Irix. (Thanks to Dai Sato.)
- - Added an experimental version of GC_memalign to mallocx.c. This can't
- always work, since we don't handle alignment requests in the hblk-level
- allocator, and we can't handle arbitrary pointer displacements unless
- GC_all_interior_pointers is enabled. But it should work for alignment
- requests up to HBLKSIZE. This is not yet documented in the standard
- places.
- - Finally debugged the OSF1/Tru64 thread support. This needs more testing,
- since I needed to add a somewhat unconvincing workaround for signal
- delivery issues that I don't yet completely understand. But it does
- pass my tests, even in parallel GC mode. Incremental GC support is
- disabled if thread support is enabled, due to the signal issues.
- - Eliminated name-space-incorrect definition of _cdecl from gc_cpp.h.
- - Added GC_debug_malloc_replacement and GC_debug_realloc_replacement
- declarations to gc.h. On IA64, this is required for REDIRECT_MALLOC
- to work correctly with these.
- - Fixed Linux USE_PROC_FOR_LIBRARIES to work with a 64-bit /proc format.
-
-Since 6.1:
- - Guard the test for GC_DUMP_REGULARLY in misc.c with
- "#ifndef NO_DEBUGGING". Otherwise it fails to build with NO_DEBUGGING
- defined. (Thanks to Manuel Serrano.)
- - Message about retrying suspend signals was incorrectly generated even when
- flag was not set.
- - Cleaned up MACOSX/NEXT root registration code. There was apparently a
- separate ifdef case in GC_register_data_segments() for no reason.
- - Removed MPROTECT_VDB for MACOSX port, based on one negative report.
- - Arrange for gc.h and friends to be correctly installed with GNU-style
- "make install".
- - Enable the GNU-style build facility include C++ support in the library
- with --enable-cplusplus. (Thanks to Thomas Maier for some of the patch.)
- - Mark from GC_thread_key in linux_threads.c, in case that's allocated
- from the garbage collected heap, as it is with our own thread-specific
- storage implementation. (Thanks to Jeff Sturm.)
- - Mark all free list header blocks if they are heap allocated. This avoids
- some unnecessary tracing. And it remains correct if we clear the
- root set. (Thanks to Jeff Sturm for identifying the bug.)
- - Improved S390/Linux support. Add S390/Linux 64-bit support. (Thanks
- to Ulrich Weigand.)
- - Corrected the spelling of GC_{M,C}ALLOC_EXPLICTLY_TYPED to
- GC_{M,C}ALLOC_EXPLICITLY_TYPED in gc_typed.h. This is technically
- an interface change. Based on the fact that nobody reported this,
- I suspect/hope there were no clients.
- - Cleaned up gc_typed.h so that (1) it adds an extern "C" declaration
- when appropriate, (2) doesn't generate references to undefined internal
- macros, and (3) allows easier manual construction of descriptors.
- - Close the file descriptor used by GC_print_address_map().
- - Set the "close-on-exec" bit for various file descriptors maintained
- for the collector's internal use.
- - Added a hack to find memory segments owned by the system allocator
- under win32. Based on my tests, this tends to eventually find all
- segments, though it may take a while. There appear to be cleaner,
- but slower solutions under NT/XP. But they rely on an API that's
- unsupported under 9X.
- - Changed Linux PowerPC stack finding to LINUX_STACKBOTTOM. (Thanks
- to Akira Tagoh for pointing out that HEURISTIC1 doesn't work on
- 64-bit kernels.)
- - Added GC_set_free_space_divisor to avoid some Windows dll issues.
- - Added FIXUP_POINTER, POINTER_SHIFT, POINTER_MASK to allow preprocessing
- of candidate pointers for tagging, etc.
- - Always lock around GC_notify_full_gc(). Simplified code for
- invoking GC_notify_full_gc().
- - Changed the way DATASTART is defined on FreeBSD to be robust against
- an unmapped page after etext. (Thanks to Hironori Sakamoto for
- tracking down the intermittent failure.)
- - Made GC_enable() and GC_disable() official. Deprecated direct update
- of GC_dont_gc. Changed GC_gcollect to be a noop when garbage collection
- is disabled.
- - Call GC_register_dynamic_libraries before stopping the world on Linux,
- in order to avoid a potential deadlock due to the dl_iterate_phdr lock.
- - Introduced a more general mechanism for platform-dependent code to
- decide whether the main data segment should be handled separately
- from dynamic libraries, or registered by GC_register_dynamic_libraries.
- The latter is more reliable and easier on Linux with dl_iterate_phdr.
-
-Since 6.2alpha1:
- - Fixed the completely broken FreeBSD code in 6.2alpha1. (Thanks to
- Hironori Sakamoto for the patch.)
- - Changed IRIX reference in dbg_mlc.c to IRIX5. (Thanks to Marcus Herbert.)
- - Attempted to work around the problems with .S filenames and the SGI
- compiler. (Reported by several people. Untested.)
- - Worked around an HP/UX make issue with the GNU-style build process.
- - Fixed the --enable-cplusplus build machinery to allow builds without
- a C++ compiler. (That was always the intent ...)
- - Changed the debugging allocation macros to explicitly pass the return
- address for Linux and XXXBSD on hardware for which we can't get stack
- traces. Use __builtin_return_address(0) to generate it when possible.
- Some of the configuration work was cleaned up (good) and moved to gc.h
- (bad, but necessary). This should make leak detection more useful
- on a number of platforms. (Thanks to Fabian Thylman for the suggestion.)
- - Fixed compilation problems in dbg_mlc.c with GC_ADD_CALLER.
- - Bumped revision number for dynamic library.
-
-Since 6.2alpha2:
- - Don't include execinfo.h in os_dep.c when it's not needed, and may not exist.
-
-Since 6.2alpha3:
- - Use LINUX_STACKBOTTOM for >= glibc2.2 on Linux/MIPS. (See Debian bug
- # 177204)
- - Integrated Jeff Sturm and Jesse Rosenstock's MACOSX threads patches.
- - Integrated Grzegorz Jakacki's substantial GNU build patch. "Make dist"
- should now work for the GNU build process. Documentation files
- are installed under share/gc.
- - Tweaked gc_cpp.h to again support the Borland compiler. (Thanks to
- Rene Girard for pointing out the problems.)
- - Updated BCC_MAKEFILE (thanks to Rene Girard).
- - Added GC_ASSERT check for minimum thread stack size.
- - Added --enable-gc-assertions.
- - Added some web documentation to the distribution. Updated it in the
- process.
- - Separate gc_conf_macros.h from gc.h.
- - Added generic GC_THREADS client-defined macro to set the appropriate
- GC_XXX_THREADS internal macro. (gc_config_macros.h.)
- - Add debugging versions of _ignore_off_page allocation primitves.
- - Moved declarations of GC_make_closure and GC_debug_invoke_finalizer
- from gc.h to gc_priv.h.
- - Reset GC_fail_count even if only a small allocation succeeds.
- - Integrated Brian Alliet's patch for dynamic library support on Darwin.
- - gc_cpp.h's gc_cleanup destructor called GC_REGISTER_FINALIZER_IGNORE_SELF
- when it should have called the lower case version, since it was
- explicitly computing a base pointer.
-
-Since 6.2alpha4:
- - GC_invoke_finalizers could, under rare conditions, set
- GC_finalizer_mem_freed to an essentially random value. This could
- possibly cause unbounded heap growth for long-running applications
- under some conditions. (The bug was introduced in 6.1alpha5, and
- is not in gcc3.3. Thanks to Ben Hutchings for finding it.)
- - Attempted to sanitize the various DLL macros. GC_USE_DLL disappeared.
- GC_DLL is used instead. All internal tests are now on GC_DLL.
- README.macros is now more precise about the intended meaning.
- - Include DllMain in the multithreaded win32 version only if the
- collector is actually built as a dll. (Thanks to Mohan Embar for
- a version of the patch.)
- - Hide the cygwin threadAttach/Detach functions. They were violating our
- namespace rules.
- - Fixed an assertion in GC_check_heap_proc. Added GC_STATIC_ASSERT.
- (Thanks again to Ben Hutchings.)
- - Removed some obsolete definitions for Linux/PowerPC in gcconfig.h.
- - CORD_cat was not rebalancing unbalanced trees in some cases, violating
- a CORD invariant. Also tweaked the rebalancing rule for
- CORD_cat_char_star. (Thanks to Alexandr Petrosian for the bug report
- and patch.)
- - Added hand-coded structured exception handling support to mark.c.
- This should enable support of dynamic libraries under win32 with
- gcc-compiled code. (Thanks to Ranjit Mathew for the patch.)
- Turned on dynamic library scanning for win32/gcc.
- - Removed some remnants of read wrapping. (Thanks to Kenneth Schalk.)
- GC_USE_LD_WRAP ws probably broken in recent versions.
- - The build could fail on some platforms since gcconfig.h could include
- declarations mentioning ptr_t, which was not defined, e.g. when if_mach
- was built. (Thanks to Yann Dirson for pointing this out.) Also
- cleaned up tests for GC_PRIVATE_H in gcconfig.h a bit.
- - The GC_LOOP_ON_ABORT environment variable interfered with incremental
- collection, since the write fault handler was erroneously overridden.
- Handlers are now set up in the correct order.
- - It used to be possible to call GC_mark_thread_local_free_lists() while
- the world was not stopped during an incremental GC. This was not safe.
- Fortunately, it was also unnecessary. Added GC_world_stopped flag
- to avoid it. (This caused occasional crashes in GC_set_fl_marks
- with thread local allocation and incremental GC. This probably happened
- primarily on old, slow multiprocessors.)
- - Allowed overriding of MAX_THREADS in win32_threads.c from the build
- command line. (Patch from Yannis Bres.)
- - Taught the IA64/linux code to determine the register backing store base from
- /proc/self/maps after checking the __libc symbol, but before guessing.
- (__libc symbols are on the endangered list, and the guess is likely to not
- always be right for 2.6 kernels.) Restructured the code to read and parse
- /proc/self/maps so it only exists in one place (all platforms).
- - The -DUSE_PROC_FOR_LIBRARIES code was broken on Linux. It claimed that it
- also registered the main data segment, but didn't actually do so. (I don't
- think anyone actually uses this configuration, but ...)
- - Made another attempt to get --enablecplusplus to do the right thing.
- Since there are unavoidable problems with C programs linking against a
- dynamic library that includes C++ code, I separated out the c++ code into
- libgccpp.
-
-Since 6.2alpha5:
- - There was an extra underscore in the name of GC_save_registers_in_stack
- for NetBSD/SPARC. (Thanks to Jaap Boender for the patch.)
- - Integrated Brian Alliet's patch for Darwin. This restructured the
- linuxthreads/pthreads support to separate generic pthreads support
- from more the system-dependent thread-stopping code. I believe this
- should make it easier to eliminate the code duplication between
- pthreads platforms in the future. The patch included some other
- code cleanups.
- - Integrated Dan Bonachea's patch to support AIX threads. This required
- substantial manual integration, mostly due to conflicts with other
- recent threads changes. It may take another iteration to
- get it to work.
- - Removed HPUX/PA-RISC support from aix_irix_threads.c. It wasn't used
- anyway and it cluttered up the code. And anything we can do to migrate
- towards generic pthreads support is a good thing.
- - Added a more explicit test for tracing of function arguments to test.c.
- (Thanks to Dan Grayson.)
- - Added Akira Tagoh's PowerPC64 patch.
- - Fixed some bit rot in the Cygwin port. (Thanks to Dan Bonachea for
- pointing it out.) Gc.h now includes just windows.h, not winbase.h.
- - Declared GC_save_regs_in_stack() in gc_priv.h. Remove other declarations.
- - Changed --enable-cplusplus to use automake consitionals. The old way
- confused libtool. "Make install" didn't work correctly for the old version.
- Previously --enable-cplusplus was broken on cygwin.
- - Changed the C version of GC_push_regs to fail at compile time if it is
- generated with an empty body. This seems to have been the cause of one
- or two subtle failures on unusual platforms. Those failures should
- now occur at build time and be easily fixable.
-
-Since 6.2alpha6:
- - Integrated a second round of Irix/AIX patches from Dan Bonachea.
- Renamed mips_sgi_mach_dep.S back to mips_sgi_mach_dep.s, since it requires
- the Irix assembler to do the C preprocessing; gcc -E doesn't work.
- - Fixed Makefile.direct for DARWIN. (Thanks to Manuel Serrano.)
- - There was a race between GC_pthread_detach and thread exit that could
- result in a thread structure being deallocated by GC_pthread_detach
- eventhough it was still needed by the thread exit code. (Thanks to
- Dick Porter for the small test case that allowed this to be debugged.)
- - Fixed version parsing for non-alpha versions in acinclude.m4 and
- version checking in version.h.
-
-Since 6.2:
- - Integrated some NetBSD patches forwarded to me by Marc Recht. These
- were already in the NetBSD package.
- - GC_pthread_create waited for the semaphore even if pthread_create failed.
- Thanks to Dick Porter for the pthread_support.c patch. Applied the
- analogous fix for aix_irix_threads.c.
- - Added Rainer Orth's Tru64 fixes.
- - The check for exceeding the thread table size in win32 threadDetach
- was incorrect. (Thanks to Alexandr Petrosian for the patch.)
- - Applied Andrew Begel's patch to correct some reentrancy issues
- with dynamic loading on Darwin.
- - GC_CreateThread() was neglecting to duplicate the thread handle in
- the table. (Thanks to Tum Nguyen for the patch.)
- - Pass +ESdbgasm only on PA-RISC machines with vendor compiler.
- (Thanks to Roger Sayle for the patch.)
- - Applied more AIX threads patches from Scott Ananian.
-
-Since 6.3alpha1:
- - Reenabled I_HOLD_LOCK assertion in aix_irix_threads.h.
- - Put back the WINABI qualifier for GC_CreateThread. (Thanks to
- Danny Smith for the patch. 6.3alpha1 had the qualifier in one place
- but not elsewhere, which was clearly wrong.)
- - Sometimes explicitly define __private_extern__ before DARWIN dyld.h
- include. (Thanks to Andreas Tobker for postting the patch.)
- - Included signal.h from pthread_support.c. Removed GC_looping_handler,
- which was dead code.
- - GC_find_start was misdeclared by gc_pmark.h if PRINT_BLACK_LIST was
- defined. (Thanks to Glauco Masotti for testing and reporting this.)
- Changed GC_find_start to never just return 0. According to its
- comment it doesn't, and it's unclear that's correct.
- - GC_alloc_large had several largely compensating bugs in the
- computation of GC_words_wasted. (It was confused about bytes vs.
- words in two places.)
- - Integrated Slava Sysoltev's patch to support more recent versions of
- the Intel compiler on IA64/Linux.
- - Changed win32 spinlock initialization to conditionally set a spin count.
- (Emmanual Stumpf pointed out that enabling this makes a large performance
- difference on win32 multiprocessors.) Also cleaned up the win32 spinlock
- initialization code a bit.
- - Fixed thread support for HP/UX/IA64. The register backing store base for
- the main thread was sometimes not set correctly. (Thanks to Laurent
- Morichetti.)
- - Added -DEMPTY_GETENV_RESULTS flag to work around Wine problem.
- - Declare GC_stack_alloc and GC_stack_free in solaris_threads.h to
- avoid 64-bit size mismatches. (Thanks to Bernie Solomon.)
- - Fixed GC_generic_push_regs to avoid a potential and very unfortunate
- tail call optimization. This could lead to prematurely reclaimed
- objects on configurations that used the generic routine and the new
- build infrastructure (which potentially optimizes mach_dep.c).
- This was a serious bug, but it's unclear whether it has resulted in
- any real failures.
- - Fixed CORD_str to deal with signed characters. (Thanks to Alexandr
- Petrosian for noticing the problem and supplying the patch.)
- - Merged a couple of NOSYS/ECOS tests into os_dep.c from gcj. (Thanks
- to Anthony Green.)
- - Partially merged a win32 patch from Ben Hutchings, and substantially
- revised other parts of win32_threads.c. It had several problems.
- Under MinGW with a statically linked library, the main thread was
- not registered. Cygwin detached threads leaked thread descriptors.
- There were several race conditions. For now, unfortunately the
- static threads limit remains, though we increased it, and made table
- traversal cost depend on the actual thread count.
- There is also still some code duplication with pthread_support.c.
- (Thread descriptors did become much smaller, since Ben Hutchings
- removed the thread context from them.)
- - Integrated a Solaris configure.in patch from Rainer Orth.
- - Added GC_IGNORE_FB and associated warning to very partially address
- the issue of the collector treating a mapped frame buffer as part
- of the root set. (Thanks to David Peroutka for providing some
- insight. More would be helpful. Is there anything that can be used
- to at least partially identify such memory segments?)
-
-Since 6.3alpha2:
- - Removed -DSMALL_CONFIG from BCC_MAKEFILE.
- - Changed macros to test for an ARM processor (Patch from Richard Earnshaw.)
- - Mostly applied a DJGPP patch from Doug Kaufman. Especially Makefile.dj
- had suffered from serious bit rot.
- - Rewrote GC_apply_to_maps, eliminating an off-by-one subscript error,
- and a call to alloca (for lcc compatibility).
- - Changed USE_MUNMAP behavior on posixy platforms to immediately remap
- the memory with PROT_NONE instead of unmapping it. The latter risks
- an intervening mmap grabbing the address space out from underneath us.
- Updated this code to reflect a cleaner patch from Ulrich Drepper.
- - Replaced _T with _Tp in new_gc_alloc.h to avoid a MACOS X conflict.
- (Patch from Andrew Begel.)
- - Dynamically choose whether or not lock should spin on win32. (Thanks
- to Maurizio Vairani for the patch.) This may be a significant performance
- improvement for win32.
- - Fix Makefile.direct to actually include NT_STATIC_THREADS_MAKEFILE
- in the distribution. (Again thanks to Maurizio Vairani.)
- - Maybe_install_looping_handler() was accidentally exported, violating
- our name space convention.
- - Made os_dep.c use sigsetjmp and SA_NODEFER for NetBSD. (Thanks to
- Christian Limpach.) (I generalized the patch to use sigsetjmp on all
- UNIX_LIKE platforms, admittedly a slightly risky move. But it may avoid
- similar problems on some other platforms. I also cleaned up the defn
- of UNIX_LIKE a bit. - Hans)
- - Integrated Andrew Begel's Darwin threads patch, adjusted according to
- some of Fergus Hendersons's comments. (Patch didn't apply cleanly,
- errors are possible.)
- - Added another test or two for the Intel 8.0 compiler to avoid
- confusing it with gcc. The single-threaded collector should now build
- with icc, at least on ia64.
-
-Since 6.3alpha3:
- - USE_MMAP was broken by confusion in the code dealing with USE_MMAP_ANON.
- (This was pointed out, and fixes were suggested by several other people.)
- - Darwin supprt was broken in alpha3 as a result of my misintegration of
- Andrew Begel's patches. Fixed with another patch from Andrew Begel.
- - A new sanity check in pthread_stop_world.c:GC_push_all_stacks() was
- overly aggressive. We may collect from an unregistered thread during
- thread creation. Fixed by explicitly checking for that case. (Added
- GC_in_thread_creation.)
-
-Since 6.3alpha4:
- - Fix & vs && typo in GC_generic_malloc and
- GC_generic_malloc_ignore_off_page. (Propagated from the gcc tree.)
- - Removed SA_NODEFER hack from NetBSD and Solaris write-protect handler.
- (According to Christian Limpach, the NetBSD problem is fixed.
- Presumably so is the Solaris 2.3 problem.)
- - Removed placement delete from gc_cpp.h for the SGI compiler.
- (Thanks to Simon Gornall for the patch.)
- - Changed semantics of the GC_IGNORE_FB environment variable, based
- on experimentation by Nicolas Cannasse pointing out that the old
- interpretation was useless. We still need help in identifying win32
- graphics memory mappings. The current "solution" is a hack.
- - Removed "MAKEOVERRIDES =" from Makefile.am and thus Makefile.in.
- It probably made more sense in the gcc context.
- - Explicitly ensure that NEED_FIND_LIMIT is defined for {Open,Net}BSD/ELF.
- - Replaced USE_HPUX_TLS macro by USE_COMPILER_TLS, since gcc often
- supports the same extension on various platforms.
- - Added some basic (completely untested) defines for win64, in support
- of future work.
- - Declared GC_jmp_buf in os_dep.s as JMP_BUF instead of jmp_buf, fixing
- a memory overwrite bug on Solaris and perhaps other platforms.
- - Added 0 != __libc_stack_end test to GC_linux_stack_base. (Thanks to Jakub
- Jelinek, both for the patch, and for explaining the problem to me.)
- Otherwise "prelink"ing could cause the collector to fail.
- - Changed default thread local storage implementation to USE_PTHREAD_SPECIFIC
- for HP/UX with gcc. The compiler-based implementation appears to work
- only with the vendor compiler.
- - Export GC_debug_header_size and GC_USR_PTR_FROM_BASE from gc_mark.h,
- making client mark code cleaner and less dependent on GC version.
- - Export several new procedures and GC_generic_malloc from gc_mark.h
- to support user-defined kinds. Use the new procedures to replace existing
- code in gcj_mlc.c and typd_mlc.c.
- - Added support for GC_BACKTRACES.
- - Fixed a remaining problem in CORD_str with signed characters. (Thanks
- to Alexandr Petrosian for the patch.)
- - Removed supposedly redundant, but very buggy, definitions of finalizer
- macros from javaxfc.h. Fortunately this file probably has no users.
- The correct declarations were already in gc.h.
- - Also need to set GC_in_thread_creation while waiting for GC during
- thread termination, since it is also possible to collect from an
- unregistered thread in that case.
- - Define NO_GETENV for Windows CE, since getenv doesn't appear to exist.
- + some other minor WinCE fixes. (Thanks to Alain Novak.)
- - Added GC_register_describe_type_fn.
- - Arrange for debugging finalizer registration to ignore non-heap
- registrations, since the regular version of the routine also behaves
- that way.
- - GC_gcj_malloc and friends need to check for finalizers waiting to be run.
- One of the more obscure allocation routines with missing a LOCK() call.
- - Fixed cvtres invocations in NT_MAKEFILE and NT_STATIC_THREADS_MAKEFILE
- to work with VS.NET.
- - Cleaned up GC_INIT calls in test. Updated gc.man to encourage GC_INIT
- use in portable code.
- - Taught the GC to use libunwind if --enable-full-debug is specified on
- IA64 and libunwind is present.
- - The USE_MUNMAP code could get confused about the age of a block and
- prematurely unmap it. GC_unmap_old had a bug related to wrapping of
- GC_gc_no. GC_freehblk and GC_merge_unmapped didn't maintain
- hb_last_reclaimed reasonably when blocks were merged. The code was
- fixed to reflect original intent, but that may not always be an
- improvement. See todo list item.
-
-Since 6.3alpha5:
- - Define USE_GENERIC_PUSH_REGS for NetBSD/M68K.
- - Fixed the X86_64 PREFETCH macros to correctly handle ia32e (which uses
- different prefetch instructions from AMD64). (Thanks to H.J. Lu.)
- - GC_config_macros.h did not correctly define GC_WIN32_THREADS from
- GC_THREADS.
- - Added simple_example.html.
- - Merged Andrew Gray's patch to correctly restore signal handlers on
- FreeBSD.
- - Merged a patch from Andreas Jaeger to deal with prefetch-related warnings
- on x86-64. Added some other casts so that the PREFETCH macros
- always get a ptr_t argument. Removed some casts inthe PREFETCH
- implementations.
- - At Jesse Jones suggestion: Added a header guard for gc_allocator.h
- and changed GC_debug_free to clobber contents of deallocated object.
- - The signal masking code in pthread_stop_world.c contained some errors.
- In particular SIGSEGV was masked in the handler, in spite of the fact that
- it wrote to the heap. This could lead to an uncaught SIGSEGV, which
- apparently became much more likely in Linux 2.6. Also fixed some
- typos, and reduced code duplication in the same area.
- - Remove ltconfig, clean up configure messages for DGUX (thanks to
- Adrian Bunk for the patches).
- - Integrated NetBSD/OpenBSD patches from Marc Recht and Matthias Drochner.
-
-Since 6.3alpha6:
- - Compile test_cpp.cc with CXXCOMPILE instead of COMPILE.
- - Very large allocations could cause a collector hang. Correct
- calculation of GC_collect_at_heapsize.
- - GC_print_hblkfreelist printed some bogus results if USE_MUNMAP
- was defined.
- - Include gc_config_macros.h in threadlibs.c.
- - Correct MacOSX thread stop code. (Thanks to Dick Porter.)
- - SMALL_OBJ definition was off by one. This could cause crashes
- at startup. (Thanks to Zoltan Varga for narrowing this down to
- a trivial test case.)
- - Integrate Paolo Molara's patch to deal with a race in the Darwin
- thread stopping code.
- - Changed X86_64 implementation to use SA_SIGINFO in the MPROTECT_VDB
- implementation. The old approach appears to have been broken by
- recent kernels.
- - Added GC_ATTR_UNUSED to eliminate a warning in gc_allocator.h (Thanks
- to Andrew Begel.)
- - Fix GC_task_self declaration in os_dep.c. (Thanks to Andrew Pinski.)
- - Increase INITIAL_BUF_SZ in os_dep.c for Solaris /proc reads.
-
-Since gc6.3:
- - Merge gcconfig.h changes from gcc tree.
- - Unconditionally include gc_priv.h in solaris_pthreads.c, win32_threads.h,
- aix_irix_threads.c, and solaris_threads.c to get thread definitions.
- - Start marker threads in GC_thr_init, so that they get started even
- if no other threads are ever started. (Oddly enough, the parallel
- collector worked correctly, though not well, with no helper threads.)
- - Go ahead and split large blocks in GC_allochblk_nth if GC_dont_gc
- is set. (Thanks to Alexander Petrossian.)
- - GC_PRINT_BACK_HEIGHT would deadlock with thread support.
- - Let in_progress_space in backgraph.s grow dynamically.
- - Fix README.solaris2. The GC_thr_init() hack doesn't work anymore.
- - Convert GC_finalizer_mem_freed to bytes in allchblk.c.
- - Add missing declaration for GC_generic_malloc_words_small_inner.
- Without it, s390x breaks. (Thanks to Ulrich Weigand.)
- - Applied several MacOSX patches to support older tool chains.
- (Thanks to Stefan Ring.)
- - Bug fix for NetBSD/amd64. (Thanks to Marc Recht.) Add NetBSD/sh3
- support. (Thanks to Uchiyama Yasushi.)
- - Fixed an uninitialized variable in cordprnt.c. (Thanks to gcc for
- providing the warning.)
- - Eliminated some, but not all, gcc -Wall warnings.
- - Changed some old style casts to reinterpret_cast in new_gc_alloc.h.
- (Thanks to Dan Grayson.)
- - GC_extend_size_map shouldn't adjust for GC_all_interior_pointers if
- GC_DONT_ADD_BYTE_AT_END is set.
- - Changed some (long) casts to (word) in preparation for win64.
- (Thanks to Peter Colson.)
- - Changed "int stack_size" declaration in pthread_support.c to use
- size_t. (Only mattered with GC_ASSERTIONS enabled.)
- - Added CRIS (etrax) support. (Thanks to Simon Posnjak and
- Hans-Peter Nilsson.)
- - Removed GC_IGNORE_FB frame buffer recognition, and replaced
- it with a check that the mapping type is MEM_IMAGE.
- In theory, this should work much better, but it is a high
- risk change for win32. (Thanks to Ashley Bone for the crucial
- experimental data behind this, and to Rutger Ovidus for
- some further experiments.)
- - GC_allochblk_nth incremented GC_words_wasted by bytes rather than
- words.
- - Consider GC_words_wasted in GC_adj_words_allocd only if it is within
- reason. (A hack to avoid some extremely unlikely scenarios in which
- we manage to allocate only "wasted" space. 7.0 has a better fix.)
- - Changed PowerPC GC_clear implementation to use lwsync instead of
- eieio, since the documentation recommends against eieio, and
- it seems to be incorrect if the preceding memory op is a load.
- - Fixed print_block_list to print the correct kind number for
- STUBBORN. (Thanks to Rutger Ovidus.)
- - Have configure.in generate an error if it is asked to support
- pthreads, but doesn't know how to.
- - Added Kazuhiro Inaoka's patch for Renesas M32R support.
- - Have the GNU build mechanism link with -ldl. Rename THREADLIBS
- to THREADDLLIBS to reflect this. (Thanks to Sven Verdoolaege.)
- - Added Hannes Mehnert's patch for FreeBSD/SPARC support.
- - Merged some FreeBSD specific patches to threadlibs.c and dyn_load.c.
- (Thanks tp John Merryweather Cooper.)
- - Define MPROTECT_VDB on MACOSX only if threads are being used, since the
- dirty page tracking mechanism uses threads. (This avoids an undefined
- reference to _GC_darwin_register_mach_handler_thread.)
- - By popular demand, use __libc symbols only if we are built with
- USE_LIBC_PRIVATES, which is off by default, and not otherwise documented.
- - Ignore GC_enable_incremental() requests when KEEP_BACK_PTRS is set.
- The GC itself will dirty lots of pages in this cases, probably making
- it counterproductive on all platforms. And the DARWIN port crashes.
-
-Since gc6.4:
- - Integrated Paolo Molaro's patch to deal with EINTR in sem_wait.
- - Make GC_approx_sp() write to dummy location to ensure that stack
- is grown here, when sp looks reasonable, rather than later, when
- it might look like a bad memory reference. (Problem was never
- observed that I know of. But on rereading the code it seemed
- dubious.)
- - Separate out GC_with_callee_saves_pushed and sometimes call
- it from GC_suspend_handler in pthread_stop_world.c. Callee-save
- register values sometimes failed to get traced under HP/UX on
- PA-RISC. Linux/IA64 had the same problem, though non-stacked
- callee-save registers seem to be so rarely used there that nobody
- ever noticed.
- - Integrated an ancient Darwin powerpc_darwin_machine_dep.s patch
- from Andreas Tobler, which I had lost.
- - Fix compare_and_exchange implementation for gcc/IA64 to deal with
- pickier compiler versions.
- - Fixed Itanium 32-bit ABI support (HP/UX). In particular, the
- compare_and_exchange implementation didn't consider that possibility.
- - Undefine GC_pthread_detach in win32_threads.c. (Thanks to
- Tagliapietra Tommaso.)
- - Fixed inclusion of frame.h for NETBSD in os_dep.c.
- - Applied Dan Bonachea's patch to use mmap on AIX.
- - Several fixes to resurrect the Irix port on recent OS versions.
- - Change ALPHA to use LINUX_STACKBOTTOM.
- - Change SPARC64/LINUX to also use LINUX_STACKBOTTOM. Deal with potential
- bad values of __libc_stack_end on that platform. (Thanks to David Miller.)
- - Relax gctest to allow larger heap if ALIGN_DOUBLE isn't set.
- (Unnecessary in 7.0)
- - Force a define of __STDC__=0 for the IBM compiler on AIX, so that
- we get prototypes. (Unnecessary in 7.0)
- - GC_INIT definition for AIX and CYGWIN referred to DATASTART and DATAEND
- which are only defined in private include files.
- - Integrated some small gcconfig.h patches from Dan Bonachea. Also
- relaxed assertion about FreeBSD stack size in pthread_support.c.
- - Integrated Andrew Begel's darwin_stop_world.c patch for 64-bit
- support. This may need additional work.
- - Avoided potentially infinite recursion in GC_save_callers if
- the system backtrace calls malloc. The workaround currently requires
- __thread support if this code is used with threads.
- - Avoided another similar infinite recursion by conditionally
- invoking GC_save_callers in alloc.c. (Thanks to Matthias Andree
- for helping to track down both of these.)
- - Removed all traces of aix_irix_threads.c. AIX and Irix now use
- pthread_support.c and pthread_stop_world.c. The old code appeared
- to be unreliable for AIX, and was not regularly maintained.
- - On Irix, ignore segments with MA_FETCHOP or MA_NOTCACHED attributed;
- they're not always safe to read.
- - Fixed a previously vacuous assertion (diagnosed by the SGI compiler)
- in GC_remove_from_fl.
- - Fix stack_size assertion in GC_pthread_create.
- - Fix assertion in GC_steal_mark_stack.
-
-Since gc6.5:
- - Fix CPU count detection for Irix and FreeBSD. (Thanks to Dan Bonachea.)
- - Integrate Dan Bonachea's patch for the IBM XLC compiler on Darwin.
- - Integrated Andreas Tobler's FreeBSD/PowerPC patch.
- - Don't access the GC thread structure from the restart handler. It's
- unsafe, since the handler may run too late. (Thanks to Ben Maurer for
- tracking this down.)
- - Applied Christian Thalinger's patch to change comment syntax in
- alpha_mach_dep.S.
- - Added test for GC_no_dls in GC_dyld_image_add for DARWIN. (Thanks to
- Juan Jose Garcia Ripoli).
- - Use LINUX_STACKBOTTOM for Linux/SH and LINUX/ARM. (Thanks to Sugioka
- Toshinobu and Christian Thalinger.)
- - Rewrote GC_parse_map_entry. This assumed a fixed column layout of
- /proc/self/maps on Linux. This ceased to be true about 2 years ago.
- The old code is probably quite problemetic with -DREDIRECT_MALLOC. It
- is also used by default for IA64, though I haven't seen actual failures
- there.
- - More consistently define HBLKSIZE to 4096 on 64 bit architectures with
- 4K pages. (Thanks to Andrew Haley.)
- - With win32 threads, GC_stop_world needs to acquire GC_write_cs. (Thanks
- to Ben Hutchings for the observation and patch.)
- - Move up struct callinfo declaration to make gcc 4.0.2. happy.
-
-Since 6.6:
- - Add "int" to Solaris "end" and "etext" declaration in gc.h. Declared
- the symbols with underscores and as arrays, since that's what's actually
- used. Perhaps this could all just be removed? (Thanks to John Bowman.)
- - Fixed ARM GC_test_and_set code. (Thanks to Kazu Hirata and Paul Brook.)
- - Added casts for assignments to hb_last_reclaimed, which truncate the
- value. Added a cast to GC_adj_words_allocd. Use GetModuleHandleA
- when retrieving a handle to kernel32.dll under win32. (Thanks to the
- Visual Prolog developers.)
- - Added Tandem S-Series support. (Thanks to Craig McDaniel. A modified
- version of his patch was applied, and hence breakage is probably not
- his fault.)
- - Remove spurious gc:: qualifier for operator delete[] in gc_cpp.h.
- (Thanks to Hanno Boeck.)
- - Changed a test for LINUX in config_macros.h to one for __linux__.
- - Add prototypes for GC_finalizer_notifier and GC_thr_init. (Thanks to
- David Ayers.)
- - Use ld instead of nonexitent ldz instruction in Darwin FindTopOfStack.
- (Thanks to Andreas Tobler.)
- - Add support for Darwin/X86. (Thanks to Geoff Norton and the Mono
- developers.)
- - Merge in some recent gcc fixes. Add ppc64 asm code. (Thanks to Bryce
- McKinley and other gcj developers.)
- - Scan MEM_PRIVATE sections under Windows ME and predecessors.
- - Interior pointers with some largish offsets into large objects could
- be ignored, if GC_all_interior_pointers was set. (Oddly this worked
- correctly for stack references if it was not set. Otherwise it failed
- for both stack and heap references.) Thanks to Andrew McKinlay for the
- critical test case.
- - Integrated Tatsuya Bizenn's NETBSD threads support, with some
- untested changes.
- - Added GC_strdup and friends to make leak detection work correctly
- for strdup clients. (Thanks to Jon Moore.) Fixed the existing strdup
- with malloc redirection to handle a null malloc return correctly.
-
-Since gc6.7:
- - Added some support for Dragonfly BSD. (Thanks to Joerg Sonnenberger and
- Thomas Klausner.)
- - Improvements to the HP/UX section of configure.in/configure.ac.
- (Thanks to Andreas Tobler)
- - GC_unix_get_mem could neglect to release the malloc lock on Irix, under
- extremely unlikely circumstances. Thanks to Jean-Baptiste Nivois for
- some careful code reading.
- - Added support for kFreeBSD + glibc (Thanks to Petr Salinger)
- - Fix more MacOS threads memory leaks (Thanks to Allan Hsu)
- - Added initial Solaris/X86-64 support (Thanks to Rainer Orth)
-
-Since gc6.8:
- - Fix typo in PREFETCH implementation for X86_64. (Thanks to Peter Wang.)
- - Fix M68K LINUX port. (Thanks to Debian packagers.)
- - __GNUC__ was misspelled as __GNUC in new_gc_alloc.h. (Thanks to Peter Wang.)
- - Integrated Allan Hsu's patch for OS X VM deallocation problems.
- - Applied FreeBSD/X86_64 patch.
-
-Since gc6.9:
- - Remove GC_PROTO, VOLATILE, GC_PTR, and GC_CONST. Assume ANSI C compiler
- and use ANSI constructs unconditionally.
- - Introduce #elif and #error in some of the appropriate places.
- - Remove GC_printf cruft. Use stdargs.
- - Remove separate Solaris threads support. Use the more generic Posix
- implementation.
- - Use atomic_ops for atomic operations and memory barriers.
- - Clean up MPROTECT_VDB implementation. Use SA_SIGINFO wherever
- possible.
- - Remove broken SIGNALS stuff.
- - Use size_t instead of word, where appropriate.
- - Add .S.o rule to Makefile.am.
- - Officially unsupport SunOS4, several old flavors of M68K (SunOS4,
- A/UX, HP), IBM PC/RTs and RISCOS/Irix4. (I doubt the old code worked.
- If anyone cares, these should be easy to resurrect.)
- - Add EXPECT() in some critical places.
- - Redefined hb_sz and hb_body to deal with bytes rather than words.
- This affected a great deal of code. I would like to consistently use
- byte offsets and sizes where there's not a convincing reason to do
- otherwise.
- - Redefined several other variables (GC_mem_found, GC_words_allocd)
- etc. to use units of bytes. Most of these were also renamed to
- reflect that fact.
- - Killed as many "register" declarations as possible.
- - Partially replaced stubborn allocation with manual write barrier.
- It's currently broken.
- - Restructured mark code, to allow mark bits to be kept either on
- a per allocation granule or per object basis. The emphasis is
- now on the -DUSE_MARK_BYTES option, since individual bits perform
- quite badly on hyperthreaded P4s, and are probably suboptimal on
- other architectures. -DUSE_MARK_BITS is currently broken, and may
- be resurrected only for the single-threaded case. This significantly
- reduced the cache footprint required by auxiliary GC data structures.
- It also reduces space overhead for small heaps. It probably slows
- things down slightly if interior pointers are very common.
- - As part of the above, we now maintain an approximate count of set
- mark bits in each heap block.
- - As part of the above, the semantics of hb_map changed drastically.
- For MARK_BIT_PER_OBJ, it doesn't exist. For MARK_BIT_PER_GRANULE,
- it is purely a way to replace a mod instruction with a table lookup.
- (Somewhat to my surprise, this still wins on modern hardware.)
- - Removed PRINTSTATS, GATHERSTATS, and SILENT macros. Everything is
- now controlled by GC_print_stats variable and GC_PRINT_STATS
- and new GC_PRINT_VERBOSE_STATS environment variables.
- - Add GC_log_printf and use it consistently for logging output.
- - Unconditionally count the objects we reclaim in the sweep phase.
- For thread local allocation, we need that anyway, and we expect
- that's increasingly the only case that matters. And it simplifies
- the code. In general expect minor performance hacks that benefit
- only the single-threaded case to disappear.
- - Remove GC_quiet from gc.h and elsewhere.
- - Changed the heap expansion heuristic, and the definition of
- GC_free_space_divisor, to refer to live data size, instead of total
- heap size. I believe this is much more robust. It wasn't previously
- possible, because we didn't have access to live data size.
- - Thread local allocation added the extra byte in twice: Once in
- thread_local_alloc, and once in malloc_many.
- - Removed GC_malloc_words_small and GC_gcj_fast_malloc. A new
- mechanism based on the thread local allocation data structures
- is expected to be added instead. This should allow inlined code
- that is both fast and doesn't rely on collector internals.
- - Changed both free lists and reclaim lists to be indexed by granules
- instead of words, norming halving their size.
- - MERGE_SIZE is now the only option, and the macro was removed.
- (Without it, we need a memory reference to GC_all_interior_pointers
- anyway. Thus it costs us nothing.)
- - Change GC_size_map to map to granules instead of words. Make sure
- that every possible size up to TINY_FREELISTS is present.
- - Split of macros need for fast inline allocation into gc_tiny_fl.h
- in anticipation of a new inline allocator that doesn't rely on GC
- internals.
- - Changed thread local allocation to use GRANULE_BYTES and TINY_FREELISTS
- in anticipation of a merge with the inline allocation code.
- - Removed ALIGN_DOUBLE. This is mostly handled by GRANULE_BYTES.
- - Make locking on most platforms conditional on GC_need_to_lock.
-
-Since gc7.0alpha1:
- - GC_bytes_allocd was incremented by a possibly uninitialized variable
- in GC_generic_malloc_inner. (Bug introduced in gc7.0alpha1. Thanks
- to Ben Hutchings for tracking it down.)
- - Win32 fixes. (Thanks to Ben Hutchings and Maurizio Vairani.)
- - Integrated Ben Hutchings' GetWriteWatch-based virtual dirty bit
- implementation for win32.
- - Removed pc_gc.tar and floppy targets in Makefile.direct. Removed
- pc_excludes file.
- - No longer include GC_bytes_wasted when evaluating allocation progress.
- Since we are now counting live memory, it no longer makes sense.
- - Applied Davide Angelocola's configury patch. There are now separate
- Makefile.am's in the cord and tests subdirectory, more tests, etc.
- - Renamed configure.in to configure.ac.
- - Merged a very small number of Nathanael Nerode's configure.ac
- cleanups from the gcc tree. Unfortunately, that file is a bit
- different from ours.
- - Changed EINTR handling in sem_wait slightly.
- - Restructure the root marking code. Remove all traces of
- USE_GENERIC_PUSH_REGS, and effectively make it the default.
- Make it easier to pass a context pointer to the mark routine, in
- case we ever want to do precise stack marking.
- - Replace GC_start_blocking() and GC_end_blocking() with GC_do_blocking().
- This remains undocumented, and only implemented for pthreads. But it
- removes an otherwise unavoidable race with stores of callee-save
- registers.
- - Fix GC_n_mark_bits for the default MARK_BIT_PER_GRANULE case. This
- resulted in bogus complaints in heap dumps.
- - Upgrade to libatomic_ops-1.0, and update build structure to match.
- - Remove SRC_M3 support. Clean up lock initialization code in misc.c.
- - Removed gc_local_alloc.h. If THREAD_LOCAL_ALLOC is defined, the
- thread local allocation routines are now called automatically.
- - Renamed gc_inl.h back to gc_inline.h. Changed the interface appreciably
- since locking has turned into a dominant issue, and in-line allocation
- only makes sense if it's no worse than thread-local allocation.
- Gc_inline.h is now also used to implement thread-local allocation.
- - Finished replacing stubborn allocation with manual write barrier.
- Untested.
- - Use thread-local allocation code by default.
- - Added GC_register_my_thread and friends for Posix and win32.
- - Patch for GWW_VDB from Ben Hutchings.
- - Removed explicit THREAD_LOCAL_ALLOC tests, since that now always
- redefines GC_malloc.
- - Removed now unused AIX memory allocation code.
- - Various minor fixes for bugs introduced in 7.0alpha1.
-
-Since gc7.0alpha2
- - Added support for dlopen-based interception of pthread functions.
- This is only half done. The gc.h redefinitions currently interfere.
- - Integrated major automake overhaul from Petter Urkedal.
-
-Since gc7.0alpha3
- (various 6.5, 6.6 changes)
- - Removed GC_brief_async_signal_safe_sleep and used atomic_ops instead.
- (Thanks to Ben Maurer.)
- - Integrated build patches from David Angelocola and Petter Urkedal.
- - Fix dynamic-linker-based pthread call redirection.
- - Renamed RS6000 to POWERPC/AIX.
- - Allow recovery from SIGSEGV in marker on Linux. This works around
- a race in thread stack marking if /proc is used to find roots. We do
- that by default with malloc redirection and threads. This involved
- moving some GC_find_limit and SETJMP related declarations to gc_priv.h.
- - Added doc/porting.html file.
- - Added ADD_HEAP_GUARD_PAGES for sbrk/*nix platforms to debug extreme
- memory overwrite errors.
- - Added trivial NO_INCREMENTAL flag to facilitate debugging.
- - Added GC_getattr_np-based GC_get_stack_base (untested).
- - Separated thread local allocation into a separate file and added the
- beginning of win32 support for that.
-
-Since gc7.0alpha4
- (more 6.6, 6.7 changes)
- - Some Solaris fixes, including some more general changes in how
- the assembly pieces of mach_dep.c are handled.
- - Removed a lot of SOLARIS_THREADS-specific code that was only
- needed with the old implementation. This included many (mostly no-op)
- versions of GC_is_fresh.
- - Don't use atomic_ops in gc_locks.h unless we need threads.
- - Fixed USE_MARK_BITS, which is once againthe default without PARALLEL_MARK.
- - Removed Solaris GC_INIT hack. It's a workaround for a long dead bug,
- and it seemed to be wrong anyway.
- - Changed win32_threads.c to require preprocessor-based interception
- of thread routines by default. A client call to GC_use_DllMain is
- now required to get the old behavior in which DllMain is used to implicitly
- register threads. This was doen for uniformity with other platforms, and
- because the DllMain solution seemed to require very tricky code which,
- at least in the past, imposed hard bounds onthe number of threads.
- - Many small changes to make thread support work again on Cygwin.
- - Moved definition of allocator lock etc. to pthread_support.c and
- win32_threads.c for those two cases.
- - Got rid of the FASTLOCK() machinery. It doesn't seem useful on modern
- platforms.
- - Cleaned up the uncollectable allocation routines, speeding up the
- slower paths. The code did enough unnecessary work off the critical path
- that the underlying logic was getting hard to extract.
- - No longer turn off THREAD_LOCAL_ALLOC with DBG_HDRS_ALL. Indications
- are it just works, and I think the reasons for it not working disappeared
- a while ago.
- - Fixed bugs in hb_n_marks calculation and assertion.
- - Don't use __builtin_expect for pre-3.0 gcc.
- - Define GWW_VDB only for recent Microsoft tool chains.
- - Add overview.html to doc directory.
- - Fix NT_STATIC_THREADS_MAKEFILE, various compiler warnings.
- - Made thread local allocation sort of work with Cygwin. The code should
- be there to deal with other Windows variants, But non-Cygwin Windows
- threads need more bug fixes.
-
-Since gc7.0alpha5
- (more 6.7 changes)
- - Declare GC_dump() in gc.h.
- - Add --enable-large-config, which just defines the LARGE_CONFIG macro.
- - Make GlobalAlloc address alignment a bit more intuitive. (Thanks to
- Charles Mills.)
- - Use #elif in the definitions of GET_MEM.
- - Overhaul porting.html. Remove corresponding text from README.
- - Fix typo in DARWIN section of gcconfig.h.
- - Fix Darwin thread memory leak. (Thanks to Bruce Mitchener.)
- - Update x86 AO_test_and_set implementation to use "=q".
- - Add $(EXEEXT) to many tests in tests/tests.am. (Corresponds to a
- 6.7 fix, which no longer applied.)
- - Fix Darwin/PPC port.
- - Fix Cygwin/threads port.
- - Fix gcj malloc support.
- - For GNU-style make, don't build libatomic_ops unless threads are requested.
- This should allow single-threaded builds on platforms which do not
- currently support libatomic_ops.
- - Clean up and hopefully fix the CFLAGS calculation for GNU build.
- (Substantially improves things on HP/UX.)
- - Integrated Andrei Polushin's Visual C++ patches. These provide for
- stack traces, better C++ debug support, and better log file handling.
- Note that these change the location of the log file to a the path of the
- executable with a .log extension. To get the old behavior back, define
- OLD_WIN32_LOG_FILE. For the time being, I'm checking his project
- files and the like into a windows-untested subdirectory. They
- are almost certainly already out of date, but better than what we had
- before.
- - Fixed some win32 threads bugs, and added support for _beginthreadex.
- - Fix zero size thread local allocation so that explicit deallocation
- works correctly.
- - Removed serious bug in GC_malloc_uncollectable(large size).
- - Do not try to do thread-local gcj allocation in incremental mode. There
- are races in setting up the descriptor.
- - Add GC_INIT() to middle.c, fix some more GC_printfn calls.
- - Some assertions erroneously used I_HOLD_LOCK() negatively, eventhough
- it can now spuriously return TRUE.
- - Rename SUNOS5 macro and OS name to SOLARIS and SUNOS5DL to SOLARISDL.
- - On Linux and some Un*x variants, allocate memory by first trying sbrk,
- and then switching to mmap if that fails.
- - Fixed /proc/x/maps reading to deal with asynchronous deletions.
- - Fix REDIRECT_MALLOC with threads on Linux. It now usually seems to work
- with ugly hacks that include having calloc behave differently when it is
- called from ld.so or the pthreads library. A reasonable amount of
- infrastructure was added to support some of this. Thanks to Roland McGrath
- for ideas and information.
- - Import various updated build scripts.
- - Add GC_register_has_static_roots_callback. (Thanks to Andrew Haley.)
- - Fix serious bugs in GC_malloc_atomic_uncollectable().
- - Return GC_SUCCESS form GC_get_stack_base().
- - Fix several atomic_ops problems on IA64 with HP Compiler.
- - Update to atomic_ops-1.2.
- - Fix hb_n_marks description and reclaim.c assertion.
- - Various additional win32 threads fixes.
- - Enable GC_ASSERTIONS for Debug build with NT_THREADS_MAKEFILE.
-
-[gc7.0alpha7 was released and version bumped to gc7.0alpha8]
-
-Since first gc7.0alpha8 version:
- [ Some gc6.9 changes ]
- - Change FindTopOfStack decl in darwin_stop_world.c.
- - Move some static tests from misc.c to gcconfig.h. Use #error.
- - Add GC_print_free_list() function. (Thanks to Bruce Hoult.)
- - Add GC_GNU_THREADS support on HURD. (Thanks to Aleksey Demakov,
- Barry DeFreese, and possibly other Debian maintainers.)
- - __GNUC__ was misspelled as __GNUC in thread_local_alloc.h.
- (Thanks to Peter Wang.)
- - Integrated various MacOSX patches and tried to reconcile them.
- Thanks to Allan Hsu, several contributers at Apple, and probably
- others.
- - Added some casts to powerpc.h in libatomic_ops to silence warnings.
-
-FOR FURTHER UPDATES SEE ../ChangeLog FILE.
-
-To do:
- - REDIRECT_MALLOC and threads combination should work on more platforms,
- and needs more testing on Linux.
- - Clone marker inner loop to support arch-dependent prefetching,
- and counting of objects marked for finalization.
- - The USE_MUNMAP code should really use a separate data structure
- indexed by physical page to keep track of time since last use of
- a page. Using hblk headers means we lose track of ages when
- blocks are merged, and we can't unmap pages that have been allocated and
- dropped by the blacklisting code. I suspect both of these matter.
- - A dynamic libgc.so references dlopen unconditionally, but doesn't link
- against libdl.
- - GC_proc_fd for Solaris is not correctly updated in response to a
- fork() call. Thus incremental collection in the child won't work
- correctly. (Thanks to Ben Cottrell for pointing this out.)
- - --enable-redirect-malloc is mostly untested and known not to work
- on some platforms.
- - 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.
-
-FOR FURTHER UPDATES SEE ../ChangeLog FILE.
This is an attempt to acknowledge early contributions to the garbage
collector. Later contributions should instead be mentioned in
-README.changes.
+ChangeLog.
HISTORY -
The garbage collector originated as part of the run-time system for
the Russell programming language implementation. The first version of the
garbage collector was written primarily by Al Demers. It was then refined
-and mostly rewritten, primarily by Hans-J. Boehm, at Cornell U.,
+and mostly rewritten, primarily by Hans-J. Boehm, at Cornell U.,
the University of Washington, Rice University (where it was first used for
C and assembly code), Xerox PARC, SGI, and HP Labs. However, significant
contributions have also been made by many others.
-Some other contributors:
+Some other contributors:
More recent contributors are mentioned in the modification history in
-README.changes. My apologies for any omissions.
+ChangeLog. My apologies for any omissions.
The SPARC specific code was originally contributed by Mark Weiser.
The Encore Multimax modifications were supplied by
Zhong Shao performed much of the experimentation that led to the
current typed allocation facility. (His dynamic type inference code hasn't
made it into the released version of the collector, yet.)
-
-#
+#
# THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED
# OR IMPLIED. ANY USE IS AT YOUR OWN RISK.
-#
+#
# Permission is hereby granted to use or copy this program
# for any purpose, provided the above notices are retained on all copies.
# Permission to modify the code and to distribute modified code is granted,
doc/README.amiga \
doc/README.arm.cross \
doc/README.autoconf \
- doc/README.changes \
doc/README.cmake \
doc/README.contributors \
doc/README.cords \
projects / gc / commitdiff