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Annotation of OpenXM_contrib2/asir2000/gc/include/gc.h, Revision 1.1.1.1

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

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