Annotation of OpenXM_contrib/gc/gc.h, Revision 1.1
1.1 ! maekawa 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: GC_PTR GC_malloc_many(size_t lb);
! 696: #define GC_NEXT(p) (*(GC_PTR *)(p)) /* Retrieve the next element */
! 697: /* in returned list. */
! 698: extern void GC_thr_init(); /* Needed for Solaris/X86 */
! 699:
! 700: #endif /* THREADS && !SRC_M3 */
! 701:
! 702: /*
! 703: * If you are planning on putting
! 704: * the collector in a SunOS 5 dynamic library, you need to call GC_INIT()
! 705: * from the statically loaded program section.
! 706: * This circumvents a Solaris 2.X (X<=4) linker bug.
! 707: */
! 708: #if defined(sparc) || defined(__sparc)
! 709: # define GC_INIT() { extern end, etext; \
! 710: GC_noop(&end, &etext); }
! 711: #else
! 712: # if defined(__CYGWIN32__) && defined(GC_USE_DLL)
! 713: /*
! 714: * Similarly gnu-win32 DLLs need explicit initialization
! 715: */
! 716: # define GC_INIT() { GC_add_roots(DATASTART, DATAEND); }
! 717: # else
! 718: # define GC_INIT()
! 719: # endif
! 720: #endif
! 721:
! 722: #if (defined(_MSDOS) || defined(_MSC_VER)) && (_M_IX86 >= 300) \
! 723: || defined(_WIN32)
! 724: /* win32S may not free all resources on process exit. */
! 725: /* This explicitly deallocates the heap. */
! 726: GC_API void GC_win32_free_heap ();
! 727: #endif
! 728:
! 729: #ifdef __cplusplus
! 730: } /* end of extern "C" */
! 731: #endif
! 732:
! 733: #endif /* _GC_H */
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