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Annotation of OpenXM_contrib2/asir2000/gc/doc/README.win32, Revision 1.2

1.1       noro        1: The collector has at various times been compiled under Windows 95 & NT,
                      2: with the original Microsoft SDK, with Visual C++ 2.0, 4.0, and 6, with
                      3: the GNU win32 environment, with Borland 4.5,  with Watcom C, and recently
                      4: with the Digital Mars compiler.  It is likely that some of these have been
                      5: broken in the meantime.  Patches are appreciated.
                      6:
                      7: It runs under both win32s and win32, but with different semantics.
                      8: Under win32, all writable pages outside of the heaps and stack are
                      9: scanned for roots.  Thus the collector sees pointers in DLL data
                     10: segments.  Under win32s, only the main data segment is scanned.
                     11: (The main data segment should always be scanned.  Under some
                     12: versions of win32s, other regions may also be scanned.)
                     13: Thus all accessible objects should be accessible from local variables
                     14: or variables in the main data segment.  Alternatively, other data
                     15: segments (e.g. in DLLs) may be registered with the collector by
                     16: calling GC_init() and then GC_register_root_section(a), where
                     17: a is the address of some variable inside the data segment.  (Duplicate
                     18: registrations are ignored, but not terribly quickly.)
                     19:
                     20: (There are two reasons for this.  We didn't want to see many 16:16
                     21: pointers.  And the VirtualQuery call has different semantics under
                     22: the two systems, and under different versions of win32s.)
                     23:
                     24: Win32 applications compiled with some flavor of gcc currently behave
                     25: like win32s applications, in that dynamic library data segments are
                     26: not scanned.  (Gcc does not directly support Microsoft's "structured
                     27: exception handling".  It turns out that use of this feature is
1.2     ! noro       28: unavoidable if you scan arbitrary memory segments obtained from
1.1       noro       29: VirtualQuery.)
                     30:
                     31: The collector test program "gctest" is linked as a GUI application,
                     32: but does not open any windows.  Its output appears in the file
                     33: "gc.log".  It may be started from the file manager.  The hour glass
                     34: cursor may appear as long as it's running.  If it is started from the
                     35: command line, it will usually run in the background.  Wait a few
                     36: minutes (a few seconds on a modern machine) before you check the output.
                     37: You should see either a failure indication or a "Collector appears to
                     38: work" message.
                     39:
                     40: The cord test program has not been ported (but should port
                     41: easily).  A toy editor (cord/de.exe) based on cords (heavyweight
                     42: strings represented as trees) has been ported and is included.
                     43: It runs fine under either win32 or win32S.  It serves as an example
                     44: of a true Windows application, except that it was written by a
                     45: nonexpert Windows programmer.  (There are some peculiarities
                     46: in the way files are displayed.  The <cr> is displayed explicitly
                     47: for standard DOS text files.  As in the UNIX version, control
                     48: characters are displayed explicitly, but in this case as red text.
                     49: This may be suboptimal for some tastes and/or sets of default
                     50: window colors.)
                     51:
                     52: In general -DREDIRECT_MALLOC is unlikely to work unless the
                     53: application is completely statically linked.
                     54:
                     55: The collector normally allocates memory from the OS with VirtualAlloc.
                     56: This appears to cause problems under Windows NT and Windows 2000 (but
                     57: not Windows 95/98) if the memory is later passed to CreateDIBitmap.
                     58: To work around this problem, build the collector with -DUSE_GLOBAL_ALLOC.
                     59: This is currently incompatible with -DUSE_MUNMAP.  (Thanks to Jonathan
                     60: Clark for tracking this down.  There's some chance this may be fixed
                     61: in 6.1alpha4, since we now separate heap sections with an unused page.)
                     62:
                     63: For Microsoft development tools, rename NT_MAKEFILE as
                     64: MAKEFILE.  (Make sure that the CPU environment variable is defined
                     65: to be i386.)  In order to use the gc_cpp.h C++ interface, all
                     66: client code should include gc_cpp.h.
                     67:
1.2     ! noro       68: If you would prefer a VC++.NET project file, ask boehm@acm.org.  One has
        !            69: been contributed, but it seems to contain some absolute paths etc., so
        !            70: it can presumably only be a starting point, and is not in the standard
        !            71: distribution.  It is unclear (to me, Hans Boehm) whether it is feasible to
        !            72: change that.
        !            73:
1.1       noro       74: Clients may need to define GC_NOT_DLL before including gc.h, if the
                     75: collector was built as a static library (as it normally is in the
                     76: absence of thread support).
                     77:
                     78: For GNU-win32, use the regular makefile, possibly after uncommenting
                     79: the line "include Makefile.DLLs".  The latter should be necessary only
                     80: if you want to package the collector as a DLL.  The GNU-win32 port is
                     81: believed to work only for b18, not b19, probably due to linker changes
                     82: in b19.  This is probably fixable with a different definition of
                     83: DATASTART and DATAEND in gcconfig.h.
                     84:
                     85: For Borland tools, use BCC_MAKEFILE.  Note that
                     86: Borland's compiler defaults to 1 byte alignment in structures (-a1),
                     87: whereas Visual C++ appears to default to 8 byte alignment (/Zp8).
                     88: The garbage collector in its default configuration EXPECTS AT
                     89: LEAST 4 BYTE ALIGNMENT.  Thus the BORLAND DEFAULT MUST
                     90: BE OVERRIDDEN.  (In my opinion, it should usually be anyway.
                     91: I expect that -a1 introduces major performance penalties on a
                     92: 486 or Pentium.)  Note that this changes structure layouts.  (As a last
                     93: resort, gcconfig.h can be changed to allow 1 byte alignment.  But
                     94: this has significant negative performance implications.)
                     95: The Makefile is set up to assume Borland 4.5.  If you have another
                     96: version, change the line near the top.  By default, it does not
                     97: require the assembler.  If you do have the assembler, I recommend
                     98: removing the -DUSE_GENERIC.
                     99:
                    100: There is some support for incremental collection.  This is
                    101: currently pretty simple-minded.  Pages are protected.  Protection
                    102: faults are caught by a handler installed at the bottom of the handler
                    103: stack.  This is both slow and interacts poorly with a debugger.
                    104: Whenever possible, I recommend adding a call to
                    105: GC_enable_incremental at the last possible moment, after most
                    106: debugging is complete.  Unlike the UNIX versions, no system
                    107: calls are wrapped by the collector itself.  It may be necessary
                    108: to wrap ReadFile calls that use a buffer in the heap, so that the
                    109: call does not encounter a protection fault while it's running.
                    110: (As usual, none of this is an issue unless GC_enable_incremental
                    111: is called.)
                    112:
                    113: Note that incremental collection is disabled with -DSMALL_CONFIG.
                    114:
                    115: James Clark has contributed the necessary code to support win32 threads.
                    116: Use NT_THREADS_MAKEFILE (a.k.a gc.mak) instead of NT_MAKEFILE
                    117: to build this version.  Note that this requires some files whose names
                    118: are more than 8 + 3 characters long.  Thus you should unpack the tar file
                    119: so that long file names are preserved.  To build the garbage collector
                    120: test with VC++ from the command line, use
                    121:
                    122: nmake /F ".\gc.mak" CFG="gctest - Win32 Release"
                    123:
                    124: This requires that the subdirectory gctest\Release exist.
                    125: The test program and DLL will reside in the Release directory.
                    126:
                    127: This version relies on the collector residing in a dll.
                    128:
                    129: This version currently supports incremental collection only if it is
                    130: enabled before any additional threads are created.
                    131: Version 4.13 attempts to fix some of the earlier problems, but there
                    132: may be other issues.  If you need solid support for win32 threads, you
                    133: might check with Geodesic Systems.  Their collector must be licensed,
                    134: but they have invested far more time in win32-specific issues.
                    135:
                    136: Hans
                    137:
                    138: Ivan V. Demakov's README for the Watcom port:
                    139:
                    140: The collector has been compiled with Watcom C 10.6 and 11.0.
                    141: It runs under win32, win32s, and even under msdos with dos4gw
                    142: dos-extender. It should also run under OS/2, though this isn't
                    143: tested. Under win32 the collector can be built either as dll
                    144: or as static library.
                    145:
                    146: Note that all compilations were done under Windows 95 or NT.
                    147: For unknown reason compiling under Windows 3.11 for NT (one
                    148: attempt has been made) leads to broken executables.
                    149:
                    150: Incremental collection is not supported.
                    151:
                    152: cord is not ported.
                    153:
                    154: Before compiling you may need to edit WCC_MAKEFILE to set target
                    155: platform, library type (dynamic or static), calling conventions, and
                    156: optimization options.
                    157:
                    158: To compile the collector and testing programs use the command:
                    159:     wmake -f WCC_MAKEFILE
                    160:
                    161: All programs using gc should be compiled with 4-byte alignment.
                    162: For further explanations on this see comments about Borland.
                    163:
1.2     ! noro      164: If the gc is compiled as dll, the macro ``GC_DLL'' should be defined before
1.1       noro      165: including "gc.h" (for example, with -DGC_DLL compiler option). It's
                    166: important, otherwise resulting programs will not run.
                    167:
                    168: Ivan Demakov (email: ivan@tgrad.nsk.su)
                    169:
                    170: