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Annotation of OpenXM_contrib2/asir2000/gc/gc.h, Revision 1.2

1.1       noro        1: /*
                      2:  * Copyright 1988, 1989 Hans-J. Boehm, Alan J. Demers
                      3:  * Copyright (c) 1991-1995 by Xerox Corporation.  All rights reserved.
                      4:  * Copyright 1996 by Silicon Graphics.  All rights reserved.
                      5:  *
                      6:  * THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED
                      7:  * OR IMPLIED.  ANY USE IS AT YOUR OWN RISK.
                      8:  *
                      9:  * Permission is hereby granted to use or copy this program
                     10:  * for any purpose,  provided the above notices are retained on all copies.
                     11:  * Permission to modify the code and to distribute modified code is granted,
                     12:  * provided the above notices are retained, and a notice that the code was
                     13:  * modified is included with the above copyright notice.
                     14:  */
                     15:
                     16: /*
                     17:  * Note that this defines a large number of tuning hooks, which can
                     18:  * safely be ignored in nearly all cases.  For normal use it suffices
                     19:  * to call only GC_MALLOC and perhaps GC_REALLOC.
                     20:  * For better performance, also look at GC_MALLOC_ATOMIC, and
                     21:  * GC_enable_incremental.  If you need an action to be performed
                     22:  * immediately before an object is collected, look at GC_register_finalizer.
                     23:  * If you are using Solaris threads, look at the end of this file.
                     24:  * Everything else is best ignored unless you encounter performance
                     25:  * problems.
                     26:  */
                     27:
                     28: #ifndef _GC_H
                     29:
                     30: # define _GC_H
                     31: # define __GC
                     32: # include <stddef.h>
                     33:
                     34: #if defined(__CYGWIN32__) && defined(GC_USE_DLL)
                     35: #include "libgc_globals.h"
                     36: #endif
                     37:
                     38: #if defined(_MSC_VER) && defined(_DLL)
                     39: # ifdef GC_BUILD
                     40: #   define GC_API __declspec(dllexport)
                     41: # else
                     42: #   define GC_API __declspec(dllimport)
                     43: # endif
                     44: #endif
                     45:
                     46: #if defined(__WATCOMC__) && defined(GC_DLL)
                     47: # ifdef GC_BUILD
                     48: #   define GC_API extern __declspec(dllexport)
                     49: # else
                     50: #   define GC_API extern __declspec(dllimport)
                     51: # endif
                     52: #endif
                     53:
                     54: #ifndef GC_API
                     55: #define GC_API extern
                     56: #endif
                     57:
                     58: # if defined(__STDC__) || defined(__cplusplus)
                     59: #   define GC_PROTO(args) args
                     60:     typedef void * GC_PTR;
1.2     ! noro       61: #   define GC_CONST const
1.1       noro       62: # else
                     63: #   define GC_PROTO(args) ()
                     64:     typedef char * GC_PTR;
1.2     ! noro       65: #   define GC_CONST
1.1       noro       66: #  endif
                     67:
                     68: # ifdef __cplusplus
                     69:     extern "C" {
                     70: # endif
                     71:
                     72:
                     73: /* Define word and signed_word to be unsigned and signed types of the  */
                     74: /* size as char * or void *.  There seems to be no way to do this      */
                     75: /* even semi-portably.  The following is probably no better/worse      */
                     76: /* than almost anything else.                                          */
                     77: /* The ANSI standard suggests that size_t and ptr_diff_t might be      */
                     78: /* better choices.  But those appear to have incorrect definitions     */
                     79: /* on may systems.  Notably "typedef int size_t" seems to be both      */
                     80: /* frequent and WRONG.                                                 */
                     81: typedef unsigned long GC_word;
                     82: typedef long GC_signed_word;
                     83:
                     84: /* Public read-only variables */
                     85:
                     86: GC_API GC_word GC_gc_no;/* Counter incremented per collection.         */
                     87:                        /* Includes empty GCs at startup.               */
                     88:
                     89:
                     90: /* Public R/W variables */
                     91:
                     92: GC_API GC_PTR (*GC_oom_fn) GC_PROTO((size_t bytes_requested));
                     93:                        /* When there is insufficient memory to satisfy */
                     94:                        /* an allocation request, we return             */
                     95:                        /* (*GC_oom_fn)().  By default this just        */
                     96:                        /* returns 0.                                   */
                     97:                        /* If it returns, it must return 0 or a valid   */
                     98:                        /* pointer to a previously allocated heap       */
                     99:                        /* object.                                      */
                    100:
1.2     ! noro      101: GC_API int GC_find_leak;
        !           102:                        /* Do not actually garbage collect, but simply  */
        !           103:                        /* report inaccessible memory that was not      */
        !           104:                        /* deallocated with GC_free.  Initial value     */
        !           105:                        /* is determined by FIND_LEAK macro.            */
        !           106:
1.1       noro      107: GC_API int GC_quiet;   /* Disable statistics output.  Only matters if  */
                    108:                        /* collector has been compiled with statistics  */
                    109:                        /* enabled.  This involves a performance cost,  */
                    110:                        /* and is thus not the default.                 */
                    111:
1.2     ! noro      112: GC_API int GC_finalize_on_demand;
        !           113:                        /* If nonzero, finalizers will only be run in   */
        !           114:                        /* response to an eplit GC_invoke_finalizers    */
        !           115:                        /* call.  The default is determined by whether  */
        !           116:                        /* the FINALIZE_ON_DEMAND macro is defined      */
        !           117:                        /* when the collector is built.                 */
        !           118:
        !           119: GC_API int GC_java_finalization;
        !           120:                        /* Mark objects reachable from finalizable      */
        !           121:                        /* objects in a separate postpass.  This makes  */
        !           122:                        /* it a bit safer to use non-topologically-     */
        !           123:                        /* ordered finalization.  Default value is      */
        !           124:                        /* determined by JAVA_FINALIZATION macro.       */
        !           125:
1.1       noro      126: GC_API int GC_dont_gc; /* Dont collect unless explicitly requested, e.g. */
                    127:                        /* because it's not safe.                         */
                    128:
                    129: GC_API int GC_dont_expand;
                    130:                        /* Dont expand heap unless explicitly requested */
                    131:                        /* or forced to.                                */
                    132:
                    133: GC_API int GC_full_freq;    /* Number of partial collections between   */
                    134:                            /* full collections.  Matters only if       */
                    135:                            /* GC_incremental is set.                   */
1.2     ! noro      136:                            /* Full collections are also triggered if   */
        !           137:                            /* the collector detects a substantial      */
        !           138:                            /* increase in the number of in-use heap    */
        !           139:                            /* blocks.  Values in the tens are now      */
        !           140:                            /* perfectly reasonable, unlike for         */
        !           141:                            /* earlier GC versions.                     */
1.1       noro      142:
                    143: GC_API GC_word GC_non_gc_bytes;
                    144:                        /* Bytes not considered candidates for collection. */
                    145:                        /* Used only to control scheduling of collections. */
                    146:
                    147: GC_API GC_word GC_free_space_divisor;
                    148:                        /* We try to make sure that we allocate at      */
                    149:                        /* least N/GC_free_space_divisor bytes between  */
                    150:                        /* collections, where N is the heap size plus   */
                    151:                        /* a rough estimate of the root set size.       */
                    152:                        /* Initially, GC_free_space_divisor = 4.        */
                    153:                        /* Increasing its value will use less space     */
                    154:                        /* but more collection time.  Decreasing it     */
                    155:                        /* will appreciably decrease collection time    */
                    156:                        /* at the expense of space.                     */
                    157:                        /* GC_free_space_divisor = 1 will effectively   */
                    158:                        /* disable collections.                         */
                    159:
                    160: GC_API GC_word GC_max_retries;
                    161:                        /* The maximum number of GCs attempted before   */
                    162:                        /* reporting out of memory after heap           */
                    163:                        /* expansion fails.  Initially 0.               */
                    164:
                    165:
                    166: GC_API char *GC_stackbottom;   /* Cool end of user stack.              */
                    167:                                /* May be set in the client prior to    */
                    168:                                /* calling any GC_ routines.  This      */
                    169:                                /* avoids some overhead, and            */
                    170:                                /* potentially some signals that can    */
                    171:                                /* confuse debuggers.  Otherwise the    */
                    172:                                /* collector attempts to set it         */
                    173:                                /* automatically.                       */
                    174:                                /* For multithreaded code, this is the  */
                    175:                                /* cold end of the stack for the        */
                    176:                                /* primordial thread.                   */
                    177:
                    178: /* Public procedures */
                    179: /*
                    180:  * general purpose allocation routines, with roughly malloc calling conv.
                    181:  * The atomic versions promise that no relevant pointers are contained
                    182:  * in the object.  The nonatomic versions guarantee that the new object
                    183:  * is cleared.  GC_malloc_stubborn promises that no changes to the object
                    184:  * will occur after GC_end_stubborn_change has been called on the
                    185:  * result of GC_malloc_stubborn. GC_malloc_uncollectable allocates an object
                    186:  * that is scanned for pointers to collectable objects, but is not itself
                    187:  * collectable.  GC_malloc_uncollectable and GC_free called on the resulting
                    188:  * object implicitly update GC_non_gc_bytes appropriately.
                    189:  */
                    190: GC_API GC_PTR GC_malloc GC_PROTO((size_t size_in_bytes));
                    191: GC_API GC_PTR GC_malloc_atomic GC_PROTO((size_t size_in_bytes));
                    192: GC_API GC_PTR GC_malloc_uncollectable GC_PROTO((size_t size_in_bytes));
                    193: GC_API GC_PTR GC_malloc_stubborn GC_PROTO((size_t size_in_bytes));
                    194:
                    195: /* The following is only defined if the library has been suitably      */
                    196: /* compiled:                                                           */
                    197: GC_API GC_PTR GC_malloc_atomic_uncollectable GC_PROTO((size_t size_in_bytes));
                    198:
                    199: /* Explicitly deallocate an object.  Dangerous if used incorrectly.     */
                    200: /* Requires a pointer to the base of an object.                                */
                    201: /* If the argument is stubborn, it should not be changeable when freed. */
                    202: /* An object should not be enable for finalization when it is          */
                    203: /* explicitly deallocated.                                             */
                    204: /* GC_free(0) is a no-op, as required by ANSI C for free.              */
                    205: GC_API void GC_free GC_PROTO((GC_PTR object_addr));
                    206:
                    207: /*
                    208:  * Stubborn objects may be changed only if the collector is explicitly informed.
                    209:  * The collector is implicitly informed of coming change when such
                    210:  * an object is first allocated.  The following routines inform the
                    211:  * collector that an object will no longer be changed, or that it will
                    212:  * once again be changed.  Only nonNIL pointer stores into the object
                    213:  * are considered to be changes.  The argument to GC_end_stubborn_change
                    214:  * must be exacly the value returned by GC_malloc_stubborn or passed to
                    215:  * GC_change_stubborn.  (In the second case it may be an interior pointer
                    216:  * within 512 bytes of the beginning of the objects.)
                    217:  * There is a performance penalty for allowing more than
                    218:  * one stubborn object to be changed at once, but it is acceptable to
                    219:  * do so.  The same applies to dropping stubborn objects that are still
                    220:  * changeable.
                    221:  */
                    222: GC_API void GC_change_stubborn GC_PROTO((GC_PTR));
                    223: GC_API void GC_end_stubborn_change GC_PROTO((GC_PTR));
                    224:
                    225: /* Return a pointer to the base (lowest address) of an object given    */
                    226: /* a pointer to a location within the object.                          */
                    227: /* Return 0 if displaced_pointer doesn't point to within a valid       */
                    228: /* object.                                                             */
                    229: GC_API GC_PTR GC_base GC_PROTO((GC_PTR displaced_pointer));
                    230:
                    231: /* Given a pointer to the base of an object, return its size in bytes. */
                    232: /* The returned size may be slightly larger than what was originally   */
                    233: /* requested.                                                          */
                    234: GC_API size_t GC_size GC_PROTO((GC_PTR object_addr));
                    235:
                    236: /* For compatibility with C library.  This is occasionally faster than */
                    237: /* a malloc followed by a bcopy.  But if you rely on that, either here */
                    238: /* or with the standard C library, your code is broken.  In my         */
                    239: /* opinion, it shouldn't have been invented, but now we're stuck. -HB  */
                    240: /* The resulting object has the same kind as the original.             */
                    241: /* If the argument is stubborn, the result will have changes enabled.  */
                    242: /* It is an error to have changes enabled for the original object.     */
                    243: /* Follows ANSI comventions for NULL old_object.                       */
                    244: GC_API GC_PTR GC_realloc
                    245:        GC_PROTO((GC_PTR old_object, size_t new_size_in_bytes));
                    246:
                    247: /* Explicitly increase the heap size.  */
                    248: /* Returns 0 on failure, 1 on success.  */
                    249: GC_API int GC_expand_hp GC_PROTO((size_t number_of_bytes));
                    250:
                    251: /* Limit the heap size to n bytes.  Useful when you're debugging,      */
                    252: /* especially on systems that don't handle running out of memory well. */
                    253: /* n == 0 ==> unbounded.  This is the default.                         */
                    254: GC_API void GC_set_max_heap_size GC_PROTO((GC_word n));
                    255:
                    256: /* Inform the collector that a certain section of statically allocated */
                    257: /* memory contains no pointers to garbage collected memory.  Thus it   */
                    258: /* need not be scanned.  This is sometimes important if the application */
                    259: /* maps large read/write files into the address space, which could be  */
                    260: /* mistaken for dynamic library data segments on some systems.         */
                    261: GC_API void GC_exclude_static_roots GC_PROTO((GC_PTR start, GC_PTR finish));
                    262:
                    263: /* Clear the set of root segments.  Wizards only. */
                    264: GC_API void GC_clear_roots GC_PROTO((void));
                    265:
                    266: /* Add a root segment.  Wizards only. */
                    267: GC_API void GC_add_roots GC_PROTO((char * low_address,
                    268:                                   char * high_address_plus_1));
                    269:
                    270: /* Add a displacement to the set of those considered valid by the      */
                    271: /* collector.  GC_register_displacement(n) means that if p was returned */
                    272: /* by GC_malloc, then (char *)p + n will be considered to be a valid   */
                    273: /* pointer to n.  N must be small and less than the size of p.         */
                    274: /* (All pointers to the interior of objects from the stack are         */
                    275: /* considered valid in any case.  This applies to heap objects and     */
                    276: /* static data.)                                                       */
                    277: /* Preferably, this should be called before any other GC procedures.   */
                    278: /* Calling it later adds to the probability of excess memory           */
                    279: /* retention.                                                          */
                    280: /* This is a no-op if the collector was compiled with recognition of   */
                    281: /* arbitrary interior pointers enabled, which is now the default.      */
                    282: GC_API void GC_register_displacement GC_PROTO((GC_word n));
                    283:
                    284: /* The following version should be used if any debugging allocation is */
                    285: /* being done.                                                         */
                    286: GC_API void GC_debug_register_displacement GC_PROTO((GC_word n));
                    287:
                    288: /* Explicitly trigger a full, world-stop collection.   */
                    289: GC_API void GC_gcollect GC_PROTO((void));
                    290:
                    291: /* Trigger a full world-stopped collection.  Abort the collection if   */
                    292: /* and when stop_func returns a nonzero value.  Stop_func will be      */
                    293: /* called frequently, and should be reasonably fast.  This works even  */
                    294: /* if virtual dirty bits, and hence incremental collection is not      */
                    295: /* available for this architecture.  Collections can be aborted faster */
                    296: /* than normal pause times for incremental collection.  However,       */
                    297: /* aborted collections do no useful work; the next collection needs    */
                    298: /* to start from the beginning.                                                */
                    299: /* Return 0 if the collection was aborted, 1 if it succeeded.          */
                    300: typedef int (* GC_stop_func) GC_PROTO((void));
                    301: GC_API int GC_try_to_collect GC_PROTO((GC_stop_func stop_func));
                    302:
                    303: /* Return the number of bytes in the heap.  Excludes collector private */
                    304: /* data structures.  Includes empty blocks and fragmentation loss.     */
                    305: /* Includes some pages that were allocated but never written.          */
                    306: GC_API size_t GC_get_heap_size GC_PROTO((void));
                    307:
1.2     ! noro      308: /* Return a lower bound on the number of free bytes in the heap.       */
        !           309: GC_API size_t GC_get_free_bytes GC_PROTO((void));
        !           310:
1.1       noro      311: /* Return the number of bytes allocated since the last collection.     */
                    312: GC_API size_t GC_get_bytes_since_gc GC_PROTO((void));
                    313:
                    314: /* Enable incremental/generational collection. */
                    315: /* Not advisable unless dirty bits are                 */
                    316: /* available or most heap objects are          */
                    317: /* pointerfree(atomic) or immutable.           */
                    318: /* Don't use in leak finding mode.             */
                    319: /* Ignored if GC_dont_gc is true.              */
                    320: GC_API void GC_enable_incremental GC_PROTO((void));
                    321:
                    322: /* Perform some garbage collection work, if appropriate.       */
                    323: /* Return 0 if there is no more work to be done.               */
                    324: /* Typically performs an amount of work corresponding roughly  */
                    325: /* to marking from one page.  May do more work if further      */
                    326: /* progress requires it, e.g. if incremental collection is     */
                    327: /* disabled.  It is reasonable to call this in a wait loop     */
                    328: /* until it returns 0.                                         */
                    329: GC_API int GC_collect_a_little GC_PROTO((void));
                    330:
                    331: /* Allocate an object of size lb bytes.  The client guarantees that    */
                    332: /* as long as the object is live, it will be referenced by a pointer   */
                    333: /* that points to somewhere within the first 256 bytes of the object.  */
                    334: /* (This should normally be declared volatile to prevent the compiler  */
                    335: /* from invalidating this assertion.)  This routine is only useful     */
                    336: /* if a large array is being allocated.  It reduces the chance of      */
                    337: /* accidentally retaining such an array as a result of scanning an     */
                    338: /* integer that happens to be an address inside the array.  (Actually, */
                    339: /* it reduces the chance of the allocator not finding space for such   */
                    340: /* an array, since it will try hard to avoid introducing such a false  */
                    341: /* reference.)  On a SunOS 4.X or MS Windows system this is recommended */
                    342: /* for arrays likely to be larger than 100K or so.  For other systems, */
                    343: /* or if the collector is not configured to recognize all interior     */
                    344: /* pointers, the threshold is normally much higher.                    */
                    345: GC_API GC_PTR GC_malloc_ignore_off_page GC_PROTO((size_t lb));
                    346: GC_API GC_PTR GC_malloc_atomic_ignore_off_page GC_PROTO((size_t lb));
                    347:
                    348: #if defined(__sgi) && !defined(__GNUC__) && _COMPILER_VERSION >= 720
                    349: #   define GC_ADD_CALLER
                    350: #   define GC_RETURN_ADDR (GC_word)__return_address
                    351: #endif
                    352:
                    353: #ifdef GC_ADD_CALLER
                    354: #  define GC_EXTRAS GC_RETURN_ADDR, __FILE__, __LINE__
1.2     ! noro      355: #  define GC_EXTRA_PARAMS GC_word ra, GC_CONST char * descr_string,
        !           356:                          int descr_int
1.1       noro      357: #else
                    358: #  define GC_EXTRAS __FILE__, __LINE__
1.2     ! noro      359: #  define GC_EXTRA_PARAMS GC_CONST char * descr_string, int descr_int
1.1       noro      360: #endif
                    361:
                    362: /* Debugging (annotated) allocation.  GC_gcollect will check           */
                    363: /* objects allocated in this way for overwrites, etc.                  */
                    364: GC_API GC_PTR GC_debug_malloc
                    365:        GC_PROTO((size_t size_in_bytes, GC_EXTRA_PARAMS));
                    366: GC_API GC_PTR GC_debug_malloc_atomic
                    367:        GC_PROTO((size_t size_in_bytes, GC_EXTRA_PARAMS));
                    368: GC_API GC_PTR GC_debug_malloc_uncollectable
                    369:        GC_PROTO((size_t size_in_bytes, GC_EXTRA_PARAMS));
                    370: GC_API GC_PTR GC_debug_malloc_stubborn
                    371:        GC_PROTO((size_t size_in_bytes, GC_EXTRA_PARAMS));
                    372: GC_API void GC_debug_free GC_PROTO((GC_PTR object_addr));
                    373: GC_API GC_PTR GC_debug_realloc
                    374:        GC_PROTO((GC_PTR old_object, size_t new_size_in_bytes,
                    375:                  GC_EXTRA_PARAMS));
                    376:
                    377: GC_API void GC_debug_change_stubborn GC_PROTO((GC_PTR));
                    378: GC_API void GC_debug_end_stubborn_change GC_PROTO((GC_PTR));
                    379: # ifdef GC_DEBUG
                    380: #   define GC_MALLOC(sz) GC_debug_malloc(sz, GC_EXTRAS)
                    381: #   define GC_MALLOC_ATOMIC(sz) GC_debug_malloc_atomic(sz, GC_EXTRAS)
                    382: #   define GC_MALLOC_UNCOLLECTABLE(sz) GC_debug_malloc_uncollectable(sz, \
                    383:                                                        GC_EXTRAS)
                    384: #   define GC_REALLOC(old, sz) GC_debug_realloc(old, sz, GC_EXTRAS)
                    385: #   define GC_FREE(p) GC_debug_free(p)
                    386: #   define GC_REGISTER_FINALIZER(p, f, d, of, od) \
                    387:        GC_debug_register_finalizer(p, f, d, of, od)
                    388: #   define GC_REGISTER_FINALIZER_IGNORE_SELF(p, f, d, of, od) \
                    389:        GC_debug_register_finalizer_ignore_self(p, f, d, of, od)
                    390: #   define GC_MALLOC_STUBBORN(sz) GC_debug_malloc_stubborn(sz, GC_EXTRAS);
                    391: #   define GC_CHANGE_STUBBORN(p) GC_debug_change_stubborn(p)
                    392: #   define GC_END_STUBBORN_CHANGE(p) GC_debug_end_stubborn_change(p)
                    393: #   define GC_GENERAL_REGISTER_DISAPPEARING_LINK(link, obj) \
                    394:        GC_general_register_disappearing_link(link, GC_base(obj))
                    395: #   define GC_REGISTER_DISPLACEMENT(n) GC_debug_register_displacement(n)
                    396: # else
                    397: #   define GC_MALLOC(sz) GC_malloc(sz)
                    398: #   define GC_MALLOC_ATOMIC(sz) GC_malloc_atomic(sz)
                    399: #   define GC_MALLOC_UNCOLLECTABLE(sz) GC_malloc_uncollectable(sz)
                    400: #   define GC_REALLOC(old, sz) GC_realloc(old, sz)
                    401: #   define GC_FREE(p) GC_free(p)
                    402: #   define GC_REGISTER_FINALIZER(p, f, d, of, od) \
                    403:        GC_register_finalizer(p, f, d, of, od)
                    404: #   define GC_REGISTER_FINALIZER_IGNORE_SELF(p, f, d, of, od) \
                    405:        GC_register_finalizer_ignore_self(p, f, d, of, od)
                    406: #   define GC_MALLOC_STUBBORN(sz) GC_malloc_stubborn(sz)
                    407: #   define GC_CHANGE_STUBBORN(p) GC_change_stubborn(p)
                    408: #   define GC_END_STUBBORN_CHANGE(p) GC_end_stubborn_change(p)
                    409: #   define GC_GENERAL_REGISTER_DISAPPEARING_LINK(link, obj) \
                    410:        GC_general_register_disappearing_link(link, obj)
                    411: #   define GC_REGISTER_DISPLACEMENT(n) GC_register_displacement(n)
                    412: # endif
                    413: /* The following are included because they are often convenient, and   */
                    414: /* reduce the chance for a misspecifed size argument.  But calls may   */
                    415: /* expand to something syntactically incorrect if t is a complicated   */
                    416: /* type expression.                                                    */
                    417: # define GC_NEW(t) (t *)GC_MALLOC(sizeof (t))
                    418: # define GC_NEW_ATOMIC(t) (t *)GC_MALLOC_ATOMIC(sizeof (t))
                    419: # define GC_NEW_STUBBORN(t) (t *)GC_MALLOC_STUBBORN(sizeof (t))
                    420: # define GC_NEW_UNCOLLECTABLE(t) (t *)GC_MALLOC_UNCOLLECTABLE(sizeof (t))
                    421:
                    422: /* Finalization.  Some of these primitives are grossly unsafe.         */
                    423: /* The idea is to make them both cheap, and sufficient to build                */
                    424: /* a safer layer, closer to PCedar finalization.                       */
                    425: /* The interface represents my conclusions from a long discussion      */
                    426: /* with Alan Demers, Dan Greene, Carl Hauser, Barry Hayes,             */
                    427: /* Christian Jacobi, and Russ Atkinson.  It's not perfect, and         */
                    428: /* probably nobody else agrees with it.            Hans-J. Boehm  3/13/92      */
                    429: typedef void (*GC_finalization_proc)
                    430:        GC_PROTO((GC_PTR obj, GC_PTR client_data));
                    431:
                    432: GC_API void GC_register_finalizer
                    433:        GC_PROTO((GC_PTR obj, GC_finalization_proc fn, GC_PTR cd,
                    434:                  GC_finalization_proc *ofn, GC_PTR *ocd));
                    435: GC_API void GC_debug_register_finalizer
                    436:        GC_PROTO((GC_PTR obj, GC_finalization_proc fn, GC_PTR cd,
                    437:                  GC_finalization_proc *ofn, GC_PTR *ocd));
                    438:        /* When obj is no longer accessible, invoke             */
                    439:        /* (*fn)(obj, cd).  If a and b are inaccessible, and    */
                    440:        /* a points to b (after disappearing links have been    */
                    441:        /* made to disappear), then only a will be              */
                    442:        /* finalized.  (If this does not create any new         */
                    443:        /* pointers to b, then b will be finalized after the    */
                    444:        /* next collection.)  Any finalizable object that       */
                    445:        /* is reachable from itself by following one or more    */
                    446:        /* pointers will not be finalized (or collected).       */
                    447:        /* Thus cycles involving finalizable objects should     */
                    448:        /* be avoided, or broken by disappearing links.         */
                    449:        /* All but the last finalizer registered for an object  */
                    450:        /* is ignored.                                          */
                    451:        /* Finalization may be removed by passing 0 as fn.      */
                    452:        /* Finalizers are implicitly unregistered just before   */
                    453:        /* they are invoked.                                    */
                    454:        /* The old finalizer and client data are stored in      */
                    455:        /* *ofn and *ocd.                                       */
                    456:        /* Fn is never invoked on an accessible object,         */
                    457:        /* provided hidden pointers are converted to real       */
                    458:        /* pointers only if the allocation lock is held, and    */
                    459:        /* such conversions are not performed by finalization   */
                    460:        /* routines.                                            */
                    461:        /* If GC_register_finalizer is aborted as a result of   */
                    462:        /* a signal, the object may be left with no             */
                    463:        /* finalization, even if neither the old nor new        */
                    464:        /* finalizer were NULL.                                 */
                    465:        /* Obj should be the nonNULL starting address of an     */
                    466:        /* object allocated by GC_malloc or friends.            */
                    467:        /* Note that any garbage collectable object referenced  */
                    468:        /* by cd will be considered accessible until the        */
                    469:        /* finalizer is invoked.                                */
                    470:
                    471: /* Another versions of the above follow.  It ignores           */
                    472: /* self-cycles, i.e. pointers from a finalizable object to     */
                    473: /* itself.  There is a stylistic argument that this is wrong,  */
                    474: /* but it's unavoidable for C++, since the compiler may                */
                    475: /* silently introduce these.  It's also benign in that specific        */
                    476: /* case.                                                       */
                    477: GC_API void GC_register_finalizer_ignore_self
                    478:        GC_PROTO((GC_PTR obj, GC_finalization_proc fn, GC_PTR cd,
                    479:                  GC_finalization_proc *ofn, GC_PTR *ocd));
                    480: GC_API void GC_debug_register_finalizer_ignore_self
                    481:        GC_PROTO((GC_PTR obj, GC_finalization_proc fn, GC_PTR cd,
                    482:                  GC_finalization_proc *ofn, GC_PTR *ocd));
                    483:
                    484: /* The following routine may be used to break cycles between   */
                    485: /* finalizable objects, thus causing cyclic finalizable                */
                    486: /* objects to be finalized in the correct order.  Standard     */
                    487: /* use involves calling GC_register_disappearing_link(&p),     */
                    488: /* where p is a pointer that is not followed by finalization   */
                    489: /* code, and should not be considered in determining           */
                    490: /* finalization order.                                         */
                    491: GC_API int GC_register_disappearing_link GC_PROTO((GC_PTR * /* link */));
                    492:        /* Link should point to a field of a heap allocated     */
                    493:        /* object obj.  *link will be cleared when obj is       */
                    494:        /* found to be inaccessible.  This happens BEFORE any   */
                    495:        /* finalization code is invoked, and BEFORE any         */
                    496:        /* decisions about finalization order are made.         */
                    497:        /* This is useful in telling the finalizer that         */
                    498:        /* some pointers are not essential for proper           */
                    499:        /* finalization.  This may avoid finalization cycles.   */
                    500:        /* Note that obj may be resurrected by another          */
                    501:        /* finalizer, and thus the clearing of *link may        */
                    502:        /* be visible to non-finalization code.                 */
                    503:        /* There's an argument that an arbitrary action should  */
                    504:        /* be allowed here, instead of just clearing a pointer. */
                    505:        /* But this causes problems if that action alters, or   */
                    506:        /* examines connectivity.                               */
                    507:        /* Returns 1 if link was already registered, 0          */
                    508:        /* otherwise.                                           */
                    509:        /* Only exists for backward compatibility.  See below:  */
                    510:
                    511: GC_API int GC_general_register_disappearing_link
                    512:        GC_PROTO((GC_PTR * /* link */, GC_PTR obj));
                    513:        /* A slight generalization of the above. *link is       */
                    514:        /* cleared when obj first becomes inaccessible.  This   */
                    515:        /* can be used to implement weak pointers easily and    */
                    516:        /* safely. Typically link will point to a location      */
                    517:        /* holding a disguised pointer to obj.  (A pointer      */
                    518:        /* inside an "atomic" object is effectively             */
                    519:        /* disguised.)   In this way soft                       */
                    520:        /* pointers are broken before any object                */
                    521:        /* reachable from them are finalized.  Each link        */
                    522:        /* May be registered only once, i.e. with one obj       */
                    523:        /* value.  This was added after a long email discussion */
                    524:        /* with John Ellis.                                     */
                    525:        /* Obj must be a pointer to the first word of an object */
                    526:        /* we allocated.  It is unsafe to explicitly deallocate */
                    527:        /* the object containing link.  Explicitly deallocating */
                    528:        /* obj may or may not cause link to eventually be       */
                    529:        /* cleared.                                             */
                    530: GC_API int GC_unregister_disappearing_link GC_PROTO((GC_PTR * /* link */));
                    531:        /* Returns 0 if link was not actually registered.       */
                    532:        /* Undoes a registration by either of the above two     */
                    533:        /* routines.                                            */
                    534:
                    535: /* Auxiliary fns to make finalization work correctly with displaced    */
                    536: /* pointers introduced by the debugging allocators.                    */
                    537: GC_API GC_PTR GC_make_closure GC_PROTO((GC_finalization_proc fn, GC_PTR data));
                    538: GC_API void GC_debug_invoke_finalizer GC_PROTO((GC_PTR obj, GC_PTR data));
                    539:
                    540: GC_API int GC_invoke_finalizers GC_PROTO((void));
                    541:        /* Run finalizers for all objects that are ready to     */
                    542:        /* be finalized.  Return the number of finalizers       */
                    543:        /* that were run.  Normally this is also called         */
                    544:        /* implicitly during some allocations.  If              */
1.2     ! noro      545:        /* GC-finalize_on_demand is nonzero, it must be called  */
1.1       noro      546:        /* explicitly.                                          */
                    547:
                    548: /* GC_set_warn_proc can be used to redirect or filter warning messages.        */
                    549: /* p may not be a NULL pointer.                                                */
                    550: typedef void (*GC_warn_proc) GC_PROTO((char *msg, GC_word arg));
                    551: GC_API GC_warn_proc GC_set_warn_proc GC_PROTO((GC_warn_proc p));
                    552:     /* Returns old warning procedure.  */
                    553:
                    554: /* The following is intended to be used by a higher level      */
                    555: /* (e.g. cedar-like) finalization facility.  It is expected    */
                    556: /* that finalization code will arrange for hidden pointers to  */
                    557: /* disappear.  Otherwise objects can be accessed after they    */
                    558: /* have been collected.                                                */
                    559: /* Note that putting pointers in atomic objects or in          */
                    560: /* nonpointer slots of "typed" objects is equivalent to        */
                    561: /* disguising them in this way, and may have other advantages. */
                    562: # if defined(I_HIDE_POINTERS) || defined(GC_I_HIDE_POINTERS)
                    563:     typedef GC_word GC_hidden_pointer;
                    564: #   define HIDE_POINTER(p) (~(GC_hidden_pointer)(p))
                    565: #   define REVEAL_POINTER(p) ((GC_PTR)(HIDE_POINTER(p)))
                    566:     /* Converting a hidden pointer to a real pointer requires verifying        */
                    567:     /* that the object still exists.  This involves acquiring the      */
                    568:     /* allocator lock to avoid a race with the collector.              */
                    569: # endif /* I_HIDE_POINTERS */
                    570:
                    571: typedef GC_PTR (*GC_fn_type) GC_PROTO((GC_PTR client_data));
                    572: GC_API GC_PTR GC_call_with_alloc_lock
                    573:                GC_PROTO((GC_fn_type fn, GC_PTR client_data));
                    574:
                    575: /* Check that p and q point to the same object.                */
                    576: /* Fail conspicuously if they don't.                           */
                    577: /* Returns the first argument.                                 */
                    578: /* Succeeds if neither p nor q points to the heap.             */
                    579: /* May succeed if both p and q point to between heap objects.  */
                    580: GC_API GC_PTR GC_same_obj GC_PROTO((GC_PTR p, GC_PTR q));
                    581:
                    582: /* Checked pointer pre- and post- increment operations.  Note that     */
                    583: /* the second argument is in units of bytes, not multiples of the      */
                    584: /* object size.  This should either be invoked from a macro, or the    */
                    585: /* call should be automatically generated.                             */
                    586: GC_API GC_PTR GC_pre_incr GC_PROTO((GC_PTR *p, size_t how_much));
                    587: GC_API GC_PTR GC_post_incr GC_PROTO((GC_PTR *p, size_t how_much));
                    588:
                    589: /* Check that p is visible                                             */
                    590: /* to the collector as a possibly pointer containing location.         */
                    591: /* If it isn't fail conspicuously.                                     */
                    592: /* Returns the argument in all cases.  May erroneously succeed         */
                    593: /* in hard cases.  (This is intended for debugging use with            */
                    594: /* untyped allocations.  The idea is that it should be possible, though        */
                    595: /* slow, to add such a call to all indirect pointer stores.)           */
                    596: /* Currently useless for multithreaded worlds.                         */
                    597: GC_API GC_PTR GC_is_visible GC_PROTO((GC_PTR p));
                    598:
                    599: /* Check that if p is a pointer to a heap page, then it points to      */
                    600: /* a valid displacement within a heap object.                          */
                    601: /* Fail conspicuously if this property does not hold.                  */
                    602: /* Uninteresting with ALL_INTERIOR_POINTERS.                           */
                    603: /* Always returns its argument.                                                */
                    604: GC_API GC_PTR GC_is_valid_displacement GC_PROTO((GC_PTR        p));
                    605:
                    606: /* Safer, but slow, pointer addition.  Probably useful mainly with     */
                    607: /* a preprocessor.  Useful only for heap pointers.                     */
                    608: #ifdef GC_DEBUG
                    609: #   define GC_PTR_ADD3(x, n, type_of_result) \
                    610:        ((type_of_result)GC_same_obj((x)+(n), (x)))
                    611: #   define GC_PRE_INCR3(x, n, type_of_result) \
                    612:        ((type_of_result)GC_pre_incr(&(x), (n)*sizeof(*x))
                    613: #   define GC_POST_INCR2(x, type_of_result) \
                    614:        ((type_of_result)GC_post_incr(&(x), sizeof(*x))
                    615: #   ifdef __GNUC__
                    616: #       define GC_PTR_ADD(x, n) \
                    617:            GC_PTR_ADD3(x, n, typeof(x))
                    618: #   define GC_PRE_INCR(x, n) \
                    619:            GC_PRE_INCR3(x, n, typeof(x))
                    620: #   define GC_POST_INCR(x, n) \
                    621:            GC_POST_INCR3(x, typeof(x))
                    622: #   else
                    623:        /* We can't do this right without typeof, which ANSI    */
                    624:        /* decided was not sufficiently useful.  Repeatedly     */
                    625:        /* mentioning the arguments seems too dangerous to be   */
                    626:        /* useful.  So does not casting the result.             */
                    627: #      define GC_PTR_ADD(x, n) ((x)+(n))
                    628: #   endif
                    629: #else  /* !GC_DEBUG */
                    630: #   define GC_PTR_ADD3(x, n, type_of_result) ((x)+(n))
                    631: #   define GC_PTR_ADD(x, n) ((x)+(n))
                    632: #   define GC_PRE_INCR3(x, n, type_of_result) ((x) += (n))
                    633: #   define GC_PRE_INCR(x, n) ((x) += (n))
                    634: #   define GC_POST_INCR2(x, n, type_of_result) ((x)++)
                    635: #   define GC_POST_INCR(x, n) ((x)++)
                    636: #endif
                    637:
                    638: /* Safer assignment of a pointer to a nonstack location.       */
                    639: #ifdef GC_DEBUG
                    640: # ifdef __STDC__
                    641: #   define GC_PTR_STORE(p, q) \
                    642:        (*(void **)GC_is_visible(p) = GC_is_valid_displacement(q))
                    643: # else
                    644: #   define GC_PTR_STORE(p, q) \
                    645:        (*(char **)GC_is_visible(p) = GC_is_valid_displacement(q))
                    646: # endif
                    647: #else /* !GC_DEBUG */
                    648: #   define GC_PTR_STORE(p, q) *((p) = (q))
                    649: #endif
                    650:
                    651: /* Fynctions called to report pointer checking errors */
                    652: GC_API void (*GC_same_obj_print_proc) GC_PROTO((GC_PTR p, GC_PTR q));
                    653:
                    654: GC_API void (*GC_is_valid_displacement_print_proc)
                    655:        GC_PROTO((GC_PTR p));
                    656:
                    657: GC_API void (*GC_is_visible_print_proc)
                    658:        GC_PROTO((GC_PTR p));
                    659:
                    660: #if defined(_SOLARIS_PTHREADS) && !defined(SOLARIS_THREADS)
                    661: #   define SOLARIS_THREADS
                    662: #endif
                    663:
                    664: #ifdef SOLARIS_THREADS
                    665: /* We need to intercept calls to many of the threads primitives, so    */
                    666: /* that we can locate thread stacks and stop the world.                        */
                    667: /* Note also that the collector cannot see thread specific data.       */
                    668: /* Thread specific data should generally consist of pointers to                */
                    669: /* uncollectable objects, which are deallocated using the destructor   */
                    670: /* facility in thr_keycreate.                                          */
                    671: # include <thread.h>
                    672: # include <signal.h>
                    673:   int GC_thr_create(void *stack_base, size_t stack_size,
                    674:                     void *(*start_routine)(void *), void *arg, long flags,
                    675:                     thread_t *new_thread);
                    676:   int GC_thr_join(thread_t wait_for, thread_t *departed, void **status);
                    677:   int GC_thr_suspend(thread_t target_thread);
                    678:   int GC_thr_continue(thread_t target_thread);
                    679:   void * GC_dlopen(const char *path, int mode);
                    680:
                    681: # ifdef _SOLARIS_PTHREADS
                    682: #   include <pthread.h>
                    683:     extern int GC_pthread_create(pthread_t *new_thread,
                    684:                                 const pthread_attr_t *attr,
                    685:                                 void * (*thread_execp)(void *), void *arg);
                    686:     extern int GC_pthread_join(pthread_t wait_for, void **status);
                    687:
                    688: #   undef thread_t
                    689:
                    690: #   define pthread_join GC_pthread_join
                    691: #   define pthread_create GC_pthread_create
                    692: #endif
                    693:
                    694: # define thr_create GC_thr_create
                    695: # define thr_join GC_thr_join
                    696: # define thr_suspend GC_thr_suspend
                    697: # define thr_continue GC_thr_continue
                    698: # define dlopen GC_dlopen
                    699:
                    700: # endif /* SOLARIS_THREADS */
                    701:
                    702:
1.2     ! noro      703: #if defined(IRIX_THREADS) || defined(LINUX_THREADS) || defined(HPUX_THREADS)
1.1       noro      704: /* We treat these similarly. */
                    705: # include <pthread.h>
                    706: # include <signal.h>
                    707:
                    708:   int GC_pthread_create(pthread_t *new_thread,
                    709:                         const pthread_attr_t *attr,
                    710:                        void *(*start_routine)(void *), void *arg);
                    711:   int GC_pthread_sigmask(int how, const sigset_t *set, sigset_t *oset);
                    712:   int GC_pthread_join(pthread_t thread, void **retval);
                    713:
                    714: # define pthread_create GC_pthread_create
                    715: # define pthread_sigmask GC_pthread_sigmask
                    716: # define pthread_join GC_pthread_join
                    717:
                    718: #endif /* IRIX_THREADS || LINUX_THREADS */
                    719:
                    720: # if defined(PCR) || defined(SOLARIS_THREADS) || defined(WIN32_THREADS) || \
                    721:        defined(IRIX_THREADS) || defined(LINUX_THREADS) || \
1.2     ! noro      722:        defined(IRIX_JDK_THREADS) || defined(HPUX_THREADS)
1.1       noro      723:        /* Any flavor of threads except SRC_M3. */
                    724: /* This returns a list of objects, linked through their first          */
                    725: /* word.  Its use can greatly reduce lock contention problems, since   */
                    726: /* the allocation lock can be acquired and released many fewer times.  */
                    727: /* lb must be large enough to hold the pointer field.                  */
                    728: GC_PTR GC_malloc_many(size_t lb);
                    729: #define GC_NEXT(p) (*(GC_PTR *)(p))    /* Retrieve the next element    */
                    730:                                        /* in returned list.            */
                    731: extern void GC_thr_init();     /* Needed for Solaris/X86       */
                    732:
                    733: #endif /* THREADS && !SRC_M3 */
                    734:
                    735: /*
                    736:  * If you are planning on putting
                    737:  * the collector in a SunOS 5 dynamic library, you need to call GC_INIT()
                    738:  * from the statically loaded program section.
                    739:  * This circumvents a Solaris 2.X (X<=4) linker bug.
                    740:  */
                    741: #if defined(sparc) || defined(__sparc)
                    742: #   define GC_INIT() { extern end, etext; \
                    743:                       GC_noop(&end, &etext); }
                    744: #else
                    745: # if defined(__CYGWIN32__) && defined(GC_USE_DLL)
                    746:     /*
                    747:      * Similarly gnu-win32 DLLs need explicit initialization
                    748:      */
                    749: #   define GC_INIT() { GC_add_roots(DATASTART, DATAEND); }
                    750: # else
                    751: #   define GC_INIT()
                    752: # endif
                    753: #endif
                    754:
                    755: #if (defined(_MSDOS) || defined(_MSC_VER)) && (_M_IX86 >= 300) \
                    756:      || defined(_WIN32)
                    757:   /* win32S may not free all resources on process exit.  */
                    758:   /* This explicitly deallocates the heap.              */
                    759:     GC_API void GC_win32_free_heap ();
                    760: #endif
                    761:
                    762: #ifdef __cplusplus
                    763:     }  /* end of extern "C" */
                    764: #endif
                    765:
                    766: #endif /* _GC_H */

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