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diff --git a/boehm-gc/doc/README.win32 b/boehm-gc/doc/README.win32 new file mode 100644 index 000000000..6f57db117 --- /dev/null +++ b/boehm-gc/doc/README.win32 @@ -0,0 +1,215 @@ +The collector has at various times been compiled under Windows 95 & later, NT, +and XP, with the original Microsoft SDK, with Visual C++ 2.0, 4.0, and 6, with +the GNU win32 tools, with Borland 4.5, with Watcom C, and recently +with the Digital Mars compiler. It is likely that some of these have been +broken in the meantime. Patches are appreciated. + +For historical reasons, +the collector test program "gctest" is linked as a GUI application, +but does not open any windows. Its output appears in the file +"gc.log". It may be started from the file manager. The hour glass +cursor may appear as long as it's running. If it is started from the +command line, it will usually run in the background. Wait a few +minutes (a few seconds on a modern machine) before you check the output. +You should see either a failure indication or a "Collector appears to +work" message. + +The cord test program has not been ported (but should port +easily). A toy editor (cord/de.exe) based on cords (heavyweight +strings represented as trees) has been ported and is included. +It runs fine under either win32 or win32S. It serves as an example +of a true Windows application, except that it was written by a +nonexpert Windows programmer. (There are some peculiarities +in the way files are displayed. The <cr> is displayed explicitly +for standard DOS text files. As in the UNIX version, control +characters are displayed explicitly, but in this case as red text. +This may be suboptimal for some tastes and/or sets of default +window colors.) + +In general -DREDIRECT_MALLOC is unlikely to work unless the +application is completely statically linked. + +The collector normally allocates memory from the OS with VirtualAlloc. +This appears to cause problems under Windows NT and Windows 2000 (but +not Windows 95/98) if the memory is later passed to CreateDIBitmap. +To work around this problem, build the collector with -DUSE_GLOBAL_ALLOC. +This is currently incompatible with -DUSE_MUNMAP. (Thanks to Jonathan +Clark for tracking this down. There's some chance this may be fixed +in 6.1alpha4, since we now separate heap sections with an unused page.) + +Microsoft Tools +--------------- +For Microsoft development tools, rename NT_MAKEFILE as +MAKEFILE. (Make sure that the CPU environment variable is defined +to be i386.) In order to use the gc_cpp.h C++ interface, all +client code should include gc_cpp.h. + +For historical reasons, +the collector test program "gctest" is linked as a GUI application, +but does not open any windows. Its output appears in the file +"gc.log". It may be started from the file manager. The hour glass +cursor may appear as long as it's running. If it is started from the +command line, it will usually run in the background. Wait a few +minutes (a few seconds on a modern machine) before you check the output. +You should see either a failure indication or a "Collector appears to +work" message. + +If you would prefer a VC++.NET project file, ask boehm@acm.org. One has +been contributed, but it seems to contain some absolute paths etc., so +it can presumably only be a starting point, and is not in the standard +distribution. It is unclear (to me, Hans Boehm) whether it is feasible to +change that. + +Clients may need to define GC_NOT_DLL before including gc.h, if the +collector was built as a static library (as it normally is in the +absence of thread support). + +GNU Tools +--------- +For GNU-win32, use the regular makefile, possibly after uncommenting +the line "include Makefile.DLLs". The latter should be necessary only +if you want to package the collector as a DLL. +[Is the following sentence obsolete? -HB] The GNU-win32 port is +believed to work only for b18, not b19, probably due to linker changes +in b19. This is probably fixable with a different definition of +DATASTART and DATAEND in gcconfig.h. + +The collector should also be buildable under Cygwin with either the +old standard Makefile, or with the "configure;make" machinery. + +Borland Tools +------------- +[Rarely tested.] +For Borland tools, use BCC_MAKEFILE. Note that +Borland's compiler defaults to 1 byte alignment in structures (-a1), +whereas Visual C++ appears to default to 8 byte alignment (/Zp8). +The garbage collector in its default configuration EXPECTS AT +LEAST 4 BYTE ALIGNMENT. Thus the BORLAND DEFAULT MUST +BE OVERRIDDEN. (In my opinion, it should usually be anyway. +I expect that -a1 introduces major performance penalties on a +486 or Pentium.) Note that this changes structure layouts. (As a last +resort, gcconfig.h can be changed to allow 1 byte alignment. But +this has significant negative performance implications.) +The Makefile is set up to assume Borland 4.5. If you have another +version, change the line near the top. By default, it does not +require the assembler. If you do have the assembler, I recommend +removing the -DUSE_GENERIC. + +Incremental Collection +---------------------- +There is some support for incremental collection. This is +currently pretty simple-minded. Pages are protected. Protection +faults are caught by a handler installed at the bottom of the handler +stack. This is both slow and interacts poorly with a debugger. +Whenever possible, I recommend adding a call to +GC_enable_incremental at the last possible moment, after most +debugging is complete. Unlike the UNIX versions, no system +calls are wrapped by the collector itself. It may be necessary +to wrap ReadFile calls that use a buffer in the heap, so that the +call does not encounter a protection fault while it's running. +(As usual, none of this is an issue unless GC_enable_incremental +is called.) + +Note that incremental collection is disabled with -DSMALL_CONFIG. + +Threads +------- + +James Clark has contributed the necessary code to support win32 threads +with the collector in a DLL. +Use NT_THREADS_MAKEFILE (a.k.a gc.mak) instead of NT_MAKEFILE +to build this version. Note that this requires some files whose names +are more than 8 + 3 characters long. Thus you should unpack the tar file +so that long file names are preserved. To build the garbage collector +test with VC++ from the command line, use + +nmake /F ".\gc.mak" CFG="gctest - Win32 Release" + +This requires that the subdirectory gctest\Release exist. +The test program and DLL will reside in the Release directory. + +This version relies on the collector residing in a dll. + +This version currently supports incremental collection only if it is +enabled before any additional threads are created. + +Since 6.3alpha2, threads are also better supported in static library builds +with Microsoft tools (use NT_STATIC_THREADS_MAKEFILE) and with the GNU +tools. In all cases,the collector must be built with GC_WIN32_THREADS +defined, even if the Cygwin pthreads interface is used. +(NT_STATIC_THREADS_MAKEFILE does this implicitly. Under Cygwin, +./configure --enable-threads=posix defines GC_WIN32_THREADS.) Threads must be +created with GC_CreateThread. This can be accomplished by +including gc.h and then calling CreateThread, which is redefined +by gc.h. + +For the statically linked versions, it is required that GC_init() +be called before other GC calls, since there seems to be no implicit way +to initialize the allocation lock. The easiest way to ensure this in +portable code is to call GC_INIT() from the main executable (not +a dynamic library) before calling any other GC_ routines. + +We strongly advise against using the TerminateThread() win32 API call, +especially with the garbage collector. Any use is likely to provoke a +crash in the GC, since it makes it impossible for the collector to +correctly track threads. + + +Watcom compiler +--------------- + +Ivan V. Demakov's README for the Watcom port: + +The collector has been compiled with Watcom C 10.6 and 11.0. +It runs under win32, win32s, and even under msdos with dos4gw +dos-extender. It should also run under OS/2, though this isn't +tested. Under win32 the collector can be built either as dll +or as static library. + +Note that all compilations were done under Windows 95 or NT. +For unknown reason compiling under Windows 3.11 for NT (one +attempt has been made) leads to broken executables. + +Incremental collection is not supported. + +cord is not ported. + +Before compiling you may need to edit WCC_MAKEFILE to set target +platform, library type (dynamic or static), calling conventions, and +optimization options. + +To compile the collector and testing programs use the command: + wmake -f WCC_MAKEFILE + +All programs using gc should be compiled with 4-byte alignment. +For further explanations on this see comments about Borland. + +If the gc is compiled as dll, the macro ``GC_DLL'' should be defined before +including "gc.h" (for example, with -DGC_DLL compiler option). It's +important, otherwise resulting programs will not run. + +Ivan Demakov (email: ivan@tgrad.nsk.su) + +Win32S +------ + +[The following is probably obsolete. The win32s support is still in the +collector, but I doubt anyone cares, or has tested it recently.] + +The collector runs under both win32s and win32, but with different semantics. +Under win32, all writable pages outside of the heaps and stack are +scanned for roots. Thus the collector sees pointers in DLL data +segments. Under win32s, only the main data segment is scanned. +(The main data segment should always be scanned. Under some +versions of win32s, other regions may also be scanned.) +Thus all accessible objects should be accessible from local variables +or variables in the main data segment. Alternatively, other data +segments (e.g. in DLLs) may be registered with the collector by +calling GC_init() and then GC_register_root_section(a), where +a is the address of some variable inside the data segment. (Duplicate +registrations are ignored, but not terribly quickly.) + +(There are two reasons for this. We didn't want to see many 16:16 +pointers. And the VirtualQuery call has different semantics under +the two systems, and under different versions of win32s.) + |