2 * Copyright 1988, 1989 Hans-J. Boehm, Alan J. Demers
3 * Copyright (c) 1991-1995 by Xerox Corporation. All rights reserved.
4 * Copyright 1996-1999 by Silicon Graphics. All rights reserved.
5 * Copyright 1999 by Hewlett-Packard Company. All rights reserved.
7 * THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED
8 * OR IMPLIED. ANY USE IS AT YOUR OWN RISK.
10 * Permission is hereby granted to use or copy this program
11 * for any purpose, provided the above notices are retained on all copies.
12 * Permission to modify the code and to distribute modified code is granted,
13 * provided the above notices are retained, and a notice that the code was
14 * modified is included with the above copyright notice.
18 * Note that this defines a large number of tuning hooks, which can
19 * safely be ignored in nearly all cases. For normal use it suffices
20 * to call only GC_MALLOC and perhaps GC_REALLOC.
21 * For better performance, also look at GC_MALLOC_ATOMIC, and
22 * GC_enable_incremental. If you need an action to be performed
23 * immediately before an object is collected, look at GC_register_finalizer.
24 * If you are using Solaris threads, look at the end of this file.
25 * Everything else is best ignored unless you encounter performance
33 # include "gc_config_macros.h"
35 # if defined(__STDC__) || defined(__cplusplus)
36 # define GC_PROTO(args) args
37 typedef void * GC_PTR;
38 # define GC_CONST const
40 # define GC_PROTO(args) ()
41 typedef char * GC_PTR;
50 /* Define word and signed_word to be unsigned and signed types of the */
51 /* size as char * or void *. There seems to be no way to do this */
52 /* even semi-portably. The following is probably no better/worse */
53 /* than almost anything else. */
54 /* The ANSI standard suggests that size_t and ptr_diff_t might be */
55 /* better choices. But those appear to have incorrect definitions */
56 /* on may systems. Notably "typedef int size_t" seems to be both */
57 /* frequent and WRONG. */
58 typedef unsigned long GC_word;
59 typedef long GC_signed_word;
61 /* Public read-only variables */
63 GC_API GC_word GC_gc_no;/* Counter incremented per collection. */
64 /* Includes empty GCs at startup. */
66 GC_API int GC_parallel; /* GC is parallelized for performance on */
67 /* multiprocessors. Currently set only */
68 /* implicitly if collector is built with */
69 /* -DPARALLEL_MARK and if either: */
70 /* Env variable GC_NPROC is set to > 1, or */
71 /* GC_NPROC is not set and this is an MP. */
72 /* If GC_parallel is set, incremental */
73 /* collection is only partially functional, */
74 /* and may not be desirable. */
77 /* Public R/W variables */
79 GC_API GC_PTR (*GC_oom_fn) GC_PROTO((size_t bytes_requested));
80 /* When there is insufficient memory to satisfy */
81 /* an allocation request, we return */
82 /* (*GC_oom_fn)(). By default this just */
84 /* If it returns, it must return 0 or a valid */
85 /* pointer to a previously allocated heap */
88 GC_API int GC_find_leak;
89 /* Do not actually garbage collect, but simply */
90 /* report inaccessible memory that was not */
91 /* deallocated with GC_free. Initial value */
92 /* is determined by FIND_LEAK macro. */
94 GC_API int GC_all_interior_pointers;
95 /* Arrange for pointers to object interiors to */
96 /* be recognized as valid. May not be changed */
97 /* after GC initialization. */
98 /* Initial value is determined by */
99 /* -DALL_INTERIOR_POINTERS. */
100 /* Unless DONT_ADD_BYTE_AT_END is defined, this */
101 /* also affects whether sizes are increased by */
102 /* at least a byte to allow "off the end" */
103 /* pointer recognition. */
104 /* MUST BE 0 or 1. */
106 GC_API int GC_quiet; /* Disable statistics output. Only matters if */
107 /* collector has been compiled with statistics */
108 /* enabled. This involves a performance cost, */
109 /* and is thus not the default. */
111 GC_API int GC_finalize_on_demand;
112 /* If nonzero, finalizers will only be run in */
113 /* response to an explicit GC_invoke_finalizers */
114 /* call. The default is determined by whether */
115 /* the FINALIZE_ON_DEMAND macro is defined */
116 /* when the collector is built. */
118 GC_API int GC_java_finalization;
119 /* Mark objects reachable from finalizable */
120 /* objects in a separate postpass. This makes */
121 /* it a bit safer to use non-topologically- */
122 /* ordered finalization. Default value is */
123 /* determined by JAVA_FINALIZATION macro. */
125 GC_API void (* GC_finalizer_notifier)();
126 /* Invoked by the collector when there are */
127 /* objects to be finalized. Invoked at most */
128 /* once per GC cycle. Never invoked unless */
129 /* GC_finalize_on_demand is set. */
130 /* Typically this will notify a finalization */
131 /* thread, which will call GC_invoke_finalizers */
134 GC_API int GC_dont_gc; /* != 0 ==> Dont collect. In versions 7.2a1+, */
135 /* this overrides explicit GC_gcollect() calls. */
136 /* Used as a counter, so that nested enabling */
137 /* and disabling work correctly. Should */
138 /* normally be updated with GC_enable() and */
139 /* GC_disable() calls. */
140 /* Direct assignment to GC_dont_gc is */
143 GC_API int GC_dont_expand;
144 /* Dont expand heap unless explicitly requested */
147 GC_API int GC_use_entire_heap;
148 /* Causes the nonincremental collector to use the */
149 /* entire heap before collecting. This was the only */
150 /* option for GC versions < 5.0. This sometimes */
151 /* results in more large block fragmentation, since */
152 /* very larg blocks will tend to get broken up */
153 /* during each GC cycle. It is likely to result in a */
154 /* larger working set, but lower collection */
155 /* frequencies, and hence fewer instructions executed */
156 /* in the collector. */
158 GC_API int GC_full_freq; /* Number of partial collections between */
159 /* full collections. Matters only if */
160 /* GC_incremental is set. */
161 /* Full collections are also triggered if */
162 /* the collector detects a substantial */
163 /* increase in the number of in-use heap */
164 /* blocks. Values in the tens are now */
165 /* perfectly reasonable, unlike for */
166 /* earlier GC versions. */
168 GC_API GC_word GC_non_gc_bytes;
169 /* Bytes not considered candidates for collection. */
170 /* Used only to control scheduling of collections. */
171 /* Updated by GC_malloc_uncollectable and GC_free. */
174 GC_API int GC_no_dls;
175 /* Don't register dynamic library data segments. */
176 /* Wizards only. Should be used only if the */
177 /* application explicitly registers all roots. */
178 /* In Microsoft Windows environments, this will */
179 /* usually also prevent registration of the */
180 /* main data segment as part of the root set. */
182 GC_API GC_word GC_free_space_divisor;
183 /* We try to make sure that we allocate at */
184 /* least N/GC_free_space_divisor bytes between */
185 /* collections, where N is the heap size plus */
186 /* a rough estimate of the root set size. */
187 /* Initially, GC_free_space_divisor = 4. */
188 /* Increasing its value will use less space */
189 /* but more collection time. Decreasing it */
190 /* will appreciably decrease collection time */
191 /* at the expense of space. */
192 /* GC_free_space_divisor = 1 will effectively */
193 /* disable collections. */
195 GC_API GC_word GC_max_retries;
196 /* The maximum number of GCs attempted before */
197 /* reporting out of memory after heap */
198 /* expansion fails. Initially 0. */
201 GC_API char *GC_stackbottom; /* Cool end of user stack. */
202 /* May be set in the client prior to */
203 /* calling any GC_ routines. This */
204 /* avoids some overhead, and */
205 /* potentially some signals that can */
206 /* confuse debuggers. Otherwise the */
207 /* collector attempts to set it */
209 /* For multithreaded code, this is the */
210 /* cold end of the stack for the */
211 /* primordial thread. */
213 GC_API int GC_dont_precollect; /* Don't collect as part of */
214 /* initialization. Should be set only */
215 /* if the client wants a chance to */
216 /* manually initialize the root set */
217 /* before the first collection. */
218 /* Interferes with blacklisting. */
221 GC_API unsigned long GC_time_limit;
222 /* If incremental collection is enabled, */
223 /* We try to terminate collections */
224 /* after this many milliseconds. Not a */
225 /* hard time bound. Setting this to */
226 /* GC_TIME_UNLIMITED will essentially */
227 /* disable incremental collection while */
228 /* leaving generational collection */
230 # define GC_TIME_UNLIMITED 999999
231 /* Setting GC_time_limit to this value */
232 /* will disable the "pause time exceeded"*/
235 /* Public procedures */
237 /* Initialize the collector. This is only required when using thread-local
238 * allocation, since unlike the regular allocation routines, GC_local_malloc
239 * is not self-initializing. If you use GC_local_malloc you should arrange
240 * to call this somehow (e.g. from a constructor) before doing any allocation.
242 GC_API void GC_init GC_PROTO((void));
245 * general purpose allocation routines, with roughly malloc calling conv.
246 * The atomic versions promise that no relevant pointers are contained
247 * in the object. The nonatomic versions guarantee that the new object
248 * is cleared. GC_malloc_stubborn promises that no changes to the object
249 * will occur after GC_end_stubborn_change has been called on the
250 * result of GC_malloc_stubborn. GC_malloc_uncollectable allocates an object
251 * that is scanned for pointers to collectable objects, but is not itself
252 * collectable. The object is scanned even if it does not appear to
253 * be reachable. GC_malloc_uncollectable and GC_free called on the resulting
254 * object implicitly update GC_non_gc_bytes appropriately.
256 * Note that the GC_malloc_stubborn support is stubbed out by default
257 * starting in 6.0. GC_malloc_stubborn is an alias for GC_malloc unless
258 * the collector is built with STUBBORN_ALLOC defined.
260 GC_API GC_PTR GC_malloc GC_PROTO((size_t size_in_bytes));
261 GC_API GC_PTR GC_malloc_atomic GC_PROTO((size_t size_in_bytes));
262 GC_API GC_PTR GC_malloc_uncollectable GC_PROTO((size_t size_in_bytes));
263 GC_API GC_PTR GC_malloc_stubborn GC_PROTO((size_t size_in_bytes));
265 /* The following is only defined if the library has been suitably */
267 GC_API GC_PTR GC_malloc_atomic_uncollectable GC_PROTO((size_t size_in_bytes));
269 /* Explicitly deallocate an object. Dangerous if used incorrectly. */
270 /* Requires a pointer to the base of an object. */
271 /* If the argument is stubborn, it should not be changeable when freed. */
272 /* An object should not be enable for finalization when it is */
273 /* explicitly deallocated. */
274 /* GC_free(0) is a no-op, as required by ANSI C for free. */
275 GC_API void GC_free GC_PROTO((GC_PTR object_addr));
278 * Stubborn objects may be changed only if the collector is explicitly informed.
279 * The collector is implicitly informed of coming change when such
280 * an object is first allocated. The following routines inform the
281 * collector that an object will no longer be changed, or that it will
282 * once again be changed. Only nonNIL pointer stores into the object
283 * are considered to be changes. The argument to GC_end_stubborn_change
284 * must be exacly the value returned by GC_malloc_stubborn or passed to
285 * GC_change_stubborn. (In the second case it may be an interior pointer
286 * within 512 bytes of the beginning of the objects.)
287 * There is a performance penalty for allowing more than
288 * one stubborn object to be changed at once, but it is acceptable to
289 * do so. The same applies to dropping stubborn objects that are still
292 GC_API void GC_change_stubborn GC_PROTO((GC_PTR));
293 GC_API void GC_end_stubborn_change GC_PROTO((GC_PTR));
295 /* Return a pointer to the base (lowest address) of an object given */
296 /* a pointer to a location within the object. */
297 /* I.e. map an interior pointer to the corresponding bas pointer. */
298 /* Note that with debugging allocation, this returns a pointer to the */
299 /* actual base of the object, i.e. the debug information, not to */
300 /* the base of the user object. */
301 /* Return 0 if displaced_pointer doesn't point to within a valid */
303 GC_API GC_PTR GC_base GC_PROTO((GC_PTR displaced_pointer));
305 /* Given a pointer to the base of an object, return its size in bytes. */
306 /* The returned size may be slightly larger than what was originally */
308 GC_API size_t GC_size GC_PROTO((GC_PTR object_addr));
310 /* For compatibility with C library. This is occasionally faster than */
311 /* a malloc followed by a bcopy. But if you rely on that, either here */
312 /* or with the standard C library, your code is broken. In my */
313 /* opinion, it shouldn't have been invented, but now we're stuck. -HB */
314 /* The resulting object has the same kind as the original. */
315 /* If the argument is stubborn, the result will have changes enabled. */
316 /* It is an error to have changes enabled for the original object. */
317 /* Follows ANSI comventions for NULL old_object. */
318 GC_API GC_PTR GC_realloc
319 GC_PROTO((GC_PTR old_object, size_t new_size_in_bytes));
321 /* Explicitly increase the heap size. */
322 /* Returns 0 on failure, 1 on success. */
323 GC_API int GC_expand_hp GC_PROTO((size_t number_of_bytes));
325 /* Limit the heap size to n bytes. Useful when you're debugging, */
326 /* especially on systems that don't handle running out of memory well. */
327 /* n == 0 ==> unbounded. This is the default. */
328 GC_API void GC_set_max_heap_size GC_PROTO((GC_word n));
330 /* Inform the collector that a certain section of statically allocated */
331 /* memory contains no pointers to garbage collected memory. Thus it */
332 /* need not be scanned. This is sometimes important if the application */
333 /* maps large read/write files into the address space, which could be */
334 /* mistaken for dynamic library data segments on some systems. */
335 GC_API void GC_exclude_static_roots GC_PROTO((GC_PTR start, GC_PTR finish));
337 /* Clear the set of root segments. Wizards only. */
338 GC_API void GC_clear_roots GC_PROTO((void));
340 /* Add a root segment. Wizards only. */
341 GC_API void GC_add_roots GC_PROTO((char * low_address,
342 char * high_address_plus_1));
344 /* Remove a root segment. Wizards only. */
345 GC_API void GC_remove_roots GC_PROTO((char * low_address,
346 char * high_address_plus_1));
348 /* Add a displacement to the set of those considered valid by the */
349 /* collector. GC_register_displacement(n) means that if p was returned */
350 /* by GC_malloc, then (char *)p + n will be considered to be a valid */
351 /* pointer to p. N must be small and less than the size of p. */
352 /* (All pointers to the interior of objects from the stack are */
353 /* considered valid in any case. This applies to heap objects and */
355 /* Preferably, this should be called before any other GC procedures. */
356 /* Calling it later adds to the probability of excess memory */
358 /* This is a no-op if the collector has recognition of */
359 /* arbitrary interior pointers enabled, which is now the default. */
360 GC_API void GC_register_displacement GC_PROTO((GC_word n));
362 /* The following version should be used if any debugging allocation is */
364 GC_API void GC_debug_register_displacement GC_PROTO((GC_word n));
366 /* Explicitly trigger a full, world-stop collection. */
367 GC_API void GC_gcollect GC_PROTO((void));
369 /* Trigger a full world-stopped collection. Abort the collection if */
370 /* and when stop_func returns a nonzero value. Stop_func will be */
371 /* called frequently, and should be reasonably fast. This works even */
372 /* if virtual dirty bits, and hence incremental collection is not */
373 /* available for this architecture. Collections can be aborted faster */
374 /* than normal pause times for incremental collection. However, */
375 /* aborted collections do no useful work; the next collection needs */
376 /* to start from the beginning. */
377 /* Return 0 if the collection was aborted, 1 if it succeeded. */
378 typedef int (* GC_stop_func) GC_PROTO((void));
379 GC_API int GC_try_to_collect GC_PROTO((GC_stop_func stop_func));
381 /* Return the number of bytes in the heap. Excludes collector private */
382 /* data structures. Includes empty blocks and fragmentation loss. */
383 /* Includes some pages that were allocated but never written. */
384 GC_API size_t GC_get_heap_size GC_PROTO((void));
386 /* Return a lower bound on the number of free bytes in the heap. */
387 GC_API size_t GC_get_free_bytes GC_PROTO((void));
389 /* Return the number of bytes allocated since the last collection. */
390 GC_API size_t GC_get_bytes_since_gc GC_PROTO((void));
392 /* Return the total number of bytes allocated in this process. */
393 /* Never decreases, except due to wrapping. */
394 GC_API size_t GC_get_total_bytes GC_PROTO((void));
396 /* Disable garbage collection. Even GC_gcollect calls will be */
398 GC_API void GC_disable GC_PROTO((void));
400 /* Reenable garbage collection. GC_diable() and GC_enable() calls */
401 /* nest. Garbage collection is enabled if the number of calls to both */
402 /* both functions is equal. */
403 GC_API void GC_enable GC_PROTO((void));
405 /* Enable incremental/generational collection. */
406 /* Not advisable unless dirty bits are */
407 /* available or most heap objects are */
408 /* pointerfree(atomic) or immutable. */
409 /* Don't use in leak finding mode. */
410 /* Ignored if GC_dont_gc is true. */
411 /* Only the generational piece of this is */
412 /* functional if GC_parallel is TRUE */
413 /* or if GC_time_limit is GC_TIME_UNLIMITED. */
414 /* Causes GC_local_gcj_malloc() to revert to */
415 /* locked allocation. Must be called */
416 /* before any GC_local_gcj_malloc() calls. */
417 GC_API void GC_enable_incremental GC_PROTO((void));
419 /* Does incremental mode write-protect pages? Returns zero or */
420 /* more of the following, or'ed together: */
421 #define GC_PROTECTS_POINTER_HEAP 1 /* May protect non-atomic objs. */
422 #define GC_PROTECTS_PTRFREE_HEAP 2
423 #define GC_PROTECTS_STATIC_DATA 4 /* Curently never. */
424 #define GC_PROTECTS_STACK 8 /* Probably impractical. */
426 #define GC_PROTECTS_NONE 0
427 GC_API int GC_incremental_protection_needs GC_PROTO((void));
429 /* Perform some garbage collection work, if appropriate. */
430 /* Return 0 if there is no more work to be done. */
431 /* Typically performs an amount of work corresponding roughly */
432 /* to marking from one page. May do more work if further */
433 /* progress requires it, e.g. if incremental collection is */
434 /* disabled. It is reasonable to call this in a wait loop */
435 /* until it returns 0. */
436 GC_API int GC_collect_a_little GC_PROTO((void));
438 /* Allocate an object of size lb bytes. The client guarantees that */
439 /* as long as the object is live, it will be referenced by a pointer */
440 /* that points to somewhere within the first 256 bytes of the object. */
441 /* (This should normally be declared volatile to prevent the compiler */
442 /* from invalidating this assertion.) This routine is only useful */
443 /* if a large array is being allocated. It reduces the chance of */
444 /* accidentally retaining such an array as a result of scanning an */
445 /* integer that happens to be an address inside the array. (Actually, */
446 /* it reduces the chance of the allocator not finding space for such */
447 /* an array, since it will try hard to avoid introducing such a false */
448 /* reference.) On a SunOS 4.X or MS Windows system this is recommended */
449 /* for arrays likely to be larger than 100K or so. For other systems, */
450 /* or if the collector is not configured to recognize all interior */
451 /* pointers, the threshold is normally much higher. */
452 GC_API GC_PTR GC_malloc_ignore_off_page GC_PROTO((size_t lb));
453 GC_API GC_PTR GC_malloc_atomic_ignore_off_page GC_PROTO((size_t lb));
455 #if defined(__sgi) && !defined(__GNUC__) && _COMPILER_VERSION >= 720
456 # define GC_ADD_CALLER
457 # define GC_RETURN_ADDR (GC_word)__return_address
461 # include <features.h>
462 # if (__GLIBC__ == 2 && __GLIBC_MINOR__ >= 1 || __GLIBC__ > 2) \
463 && !defined(__ia64__)
464 # define GC_HAVE_BUILTIN_BACKTRACE
465 # define GC_CAN_SAVE_CALL_STACKS
467 # if defined(__i386__) || defined(__x86_64__)
468 # define GC_CAN_SAVE_CALL_STACKS
472 #if defined(__sparc__)
473 # define GC_CAN_SAVE_CALL_STACKS
476 /* If we're on an a platform on which we can't save call stacks, but */
477 /* gcc is normally used, we go ahead and define GC_ADD_CALLER. */
478 /* We make this decision independent of whether gcc is actually being */
479 /* used, in order to keep the interface consistent, and allow mixing */
481 /* This may also be desirable if it is possible but expensive to */
482 /* retrieve the call chain. */
483 #if (defined(__linux__) || defined(__NetBSD__) || defined(__OpenBSD__) \
484 || defined(__FreeBSD__)) & !defined(GC_CAN_SAVE_CALL_STACKS)
485 # define GC_ADD_CALLER
486 # if __GNUC__ >= 3 || (__GNUC__ == 2 && __GNUC_MINOR__ >= 95)
487 /* gcc knows how to retrieve return address, but we don't know */
488 /* how to generate call stacks. */
489 # define GC_RETURN_ADDR (GC_word)__builtin_return_address(0)
491 /* Just pass 0 for gcc compatibility. */
492 # define GC_RETURN_ADDR 0
497 # define GC_EXTRAS GC_RETURN_ADDR, __FILE__, __LINE__
498 # define GC_EXTRA_PARAMS GC_word ra, GC_CONST char * s, int i
500 # define GC_EXTRAS __FILE__, __LINE__
501 # define GC_EXTRA_PARAMS GC_CONST char * s, int i
504 /* Debugging (annotated) allocation. GC_gcollect will check */
505 /* objects allocated in this way for overwrites, etc. */
506 GC_API GC_PTR GC_debug_malloc
507 GC_PROTO((size_t size_in_bytes, GC_EXTRA_PARAMS));
508 GC_API GC_PTR GC_debug_malloc_atomic
509 GC_PROTO((size_t size_in_bytes, GC_EXTRA_PARAMS));
510 GC_API GC_PTR GC_debug_malloc_uncollectable
511 GC_PROTO((size_t size_in_bytes, GC_EXTRA_PARAMS));
512 GC_API GC_PTR GC_debug_malloc_stubborn
513 GC_PROTO((size_t size_in_bytes, GC_EXTRA_PARAMS));
514 GC_API GC_PTR GC_debug_malloc_ignore_off_page
515 GC_PROTO((size_t size_in_bytes, GC_EXTRA_PARAMS));
516 GC_API GC_PTR GC_debug_malloc_atomic_ignore_off_page
517 GC_PROTO((size_t size_in_bytes, GC_EXTRA_PARAMS));
518 GC_API void GC_debug_free GC_PROTO((GC_PTR object_addr));
519 GC_API GC_PTR GC_debug_realloc
520 GC_PROTO((GC_PTR old_object, size_t new_size_in_bytes,
522 GC_API void GC_debug_change_stubborn GC_PROTO((GC_PTR));
523 GC_API void GC_debug_end_stubborn_change GC_PROTO((GC_PTR));
525 /* Routines that allocate objects with debug information (like the */
526 /* above), but just fill in dummy file and line number information. */
527 /* Thus they can serve as drop-in malloc/realloc replacements. This */
528 /* can be useful for two reasons: */
529 /* 1) It allows the collector to be built with DBG_HDRS_ALL defined */
530 /* even if some allocation calls come from 3rd party libraries */
531 /* that can't be recompiled. */
532 /* 2) On some platforms, the file and line information is redundant, */
533 /* since it can be reconstructed from a stack trace. On such */
534 /* platforms it may be more convenient not to recompile, e.g. for */
535 /* leak detection. This can be accomplished by instructing the */
536 /* linker to replace malloc/realloc with these. */
537 GC_API GC_PTR GC_debug_malloc_replacement GC_PROTO((size_t size_in_bytes));
538 GC_API GC_PTR GC_debug_realloc_replacement
539 GC_PROTO((GC_PTR object_addr, size_t size_in_bytes));
542 # define GC_MALLOC(sz) GC_debug_malloc(sz, GC_EXTRAS)
543 # define GC_MALLOC_ATOMIC(sz) GC_debug_malloc_atomic(sz, GC_EXTRAS)
544 # define GC_MALLOC_UNCOLLECTABLE(sz) \
545 GC_debug_malloc_uncollectable(sz, GC_EXTRAS)
546 # define GC_MALLOC_IGNORE_OFF_PAGE(sz) \
547 GC_debug_malloc_ignore_off_page(sz, GC_EXTRAS)
548 # define GC_MALLOC_ATOMIC_IGNORE_OFF_PAGE(sz) \
549 GC_debug_malloc_atomic_ignore_off_page(sz, GC_EXTRAS)
550 # define GC_REALLOC(old, sz) GC_debug_realloc(old, sz, GC_EXTRAS)
551 # define GC_FREE(p) GC_debug_free(p)
552 # define GC_REGISTER_FINALIZER(p, f, d, of, od) \
553 GC_debug_register_finalizer(p, f, d, of, od)
554 # define GC_REGISTER_FINALIZER_IGNORE_SELF(p, f, d, of, od) \
555 GC_debug_register_finalizer_ignore_self(p, f, d, of, od)
556 # define GC_REGISTER_FINALIZER_NO_ORDER(p, f, d, of, od) \
557 GC_debug_register_finalizer_no_order(p, f, d, of, od)
558 # define GC_MALLOC_STUBBORN(sz) GC_debug_malloc_stubborn(sz, GC_EXTRAS);
559 # define GC_CHANGE_STUBBORN(p) GC_debug_change_stubborn(p)
560 # define GC_END_STUBBORN_CHANGE(p) GC_debug_end_stubborn_change(p)
561 # define GC_GENERAL_REGISTER_DISAPPEARING_LINK(link, obj) \
562 GC_general_register_disappearing_link(link, GC_base(obj))
563 # define GC_REGISTER_DISPLACEMENT(n) GC_debug_register_displacement(n)
565 # define GC_MALLOC(sz) GC_malloc(sz)
566 # define GC_MALLOC_ATOMIC(sz) GC_malloc_atomic(sz)
567 # define GC_MALLOC_UNCOLLECTABLE(sz) GC_malloc_uncollectable(sz)
568 # define GC_MALLOC_IGNORE_OFF_PAGE(sz) \
569 GC_malloc_ignore_off_page(sz)
570 # define GC_MALLOC_ATOMIC_IGNORE_OFF_PAGE(sz) \
571 GC_malloc_atomic_ignore_off_page(sz)
572 # define GC_REALLOC(old, sz) GC_realloc(old, sz)
573 # define GC_FREE(p) GC_free(p)
574 # define GC_REGISTER_FINALIZER(p, f, d, of, od) \
575 GC_register_finalizer(p, f, d, of, od)
576 # define GC_REGISTER_FINALIZER_IGNORE_SELF(p, f, d, of, od) \
577 GC_register_finalizer_ignore_self(p, f, d, of, od)
578 # define GC_REGISTER_FINALIZER_NO_ORDER(p, f, d, of, od) \
579 GC_register_finalizer_no_order(p, f, d, of, od)
580 # define GC_MALLOC_STUBBORN(sz) GC_malloc_stubborn(sz)
581 # define GC_CHANGE_STUBBORN(p) GC_change_stubborn(p)
582 # define GC_END_STUBBORN_CHANGE(p) GC_end_stubborn_change(p)
583 # define GC_GENERAL_REGISTER_DISAPPEARING_LINK(link, obj) \
584 GC_general_register_disappearing_link(link, obj)
585 # define GC_REGISTER_DISPLACEMENT(n) GC_register_displacement(n)
587 /* The following are included because they are often convenient, and */
588 /* reduce the chance for a misspecifed size argument. But calls may */
589 /* expand to something syntactically incorrect if t is a complicated */
590 /* type expression. */
591 # define GC_NEW(t) (t *)GC_MALLOC(sizeof (t))
592 # define GC_NEW_ATOMIC(t) (t *)GC_MALLOC_ATOMIC(sizeof (t))
593 # define GC_NEW_STUBBORN(t) (t *)GC_MALLOC_STUBBORN(sizeof (t))
594 # define GC_NEW_UNCOLLECTABLE(t) (t *)GC_MALLOC_UNCOLLECTABLE(sizeof (t))
596 /* Finalization. Some of these primitives are grossly unsafe. */
597 /* The idea is to make them both cheap, and sufficient to build */
598 /* a safer layer, closer to PCedar finalization. */
599 /* The interface represents my conclusions from a long discussion */
600 /* with Alan Demers, Dan Greene, Carl Hauser, Barry Hayes, */
601 /* Christian Jacobi, and Russ Atkinson. It's not perfect, and */
602 /* probably nobody else agrees with it. Hans-J. Boehm 3/13/92 */
603 typedef void (*GC_finalization_proc)
604 GC_PROTO((GC_PTR obj, GC_PTR client_data));
606 GC_API void GC_register_finalizer
607 GC_PROTO((GC_PTR obj, GC_finalization_proc fn, GC_PTR cd,
608 GC_finalization_proc *ofn, GC_PTR *ocd));
609 GC_API void GC_debug_register_finalizer
610 GC_PROTO((GC_PTR obj, GC_finalization_proc fn, GC_PTR cd,
611 GC_finalization_proc *ofn, GC_PTR *ocd));
612 /* When obj is no longer accessible, invoke */
613 /* (*fn)(obj, cd). If a and b are inaccessible, and */
614 /* a points to b (after disappearing links have been */
615 /* made to disappear), then only a will be */
616 /* finalized. (If this does not create any new */
617 /* pointers to b, then b will be finalized after the */
618 /* next collection.) Any finalizable object that */
619 /* is reachable from itself by following one or more */
620 /* pointers will not be finalized (or collected). */
621 /* Thus cycles involving finalizable objects should */
622 /* be avoided, or broken by disappearing links. */
623 /* All but the last finalizer registered for an object */
625 /* Finalization may be removed by passing 0 as fn. */
626 /* Finalizers are implicitly unregistered just before */
627 /* they are invoked. */
628 /* The old finalizer and client data are stored in */
630 /* Fn is never invoked on an accessible object, */
631 /* provided hidden pointers are converted to real */
632 /* pointers only if the allocation lock is held, and */
633 /* such conversions are not performed by finalization */
635 /* If GC_register_finalizer is aborted as a result of */
636 /* a signal, the object may be left with no */
637 /* finalization, even if neither the old nor new */
638 /* finalizer were NULL. */
639 /* Obj should be the nonNULL starting address of an */
640 /* object allocated by GC_malloc or friends. */
641 /* Note that any garbage collectable object referenced */
642 /* by cd will be considered accessible until the */
643 /* finalizer is invoked. */
645 /* Another versions of the above follow. It ignores */
646 /* self-cycles, i.e. pointers from a finalizable object to */
647 /* itself. There is a stylistic argument that this is wrong, */
648 /* but it's unavoidable for C++, since the compiler may */
649 /* silently introduce these. It's also benign in that specific */
650 /* case. And it helps if finalizable objects are split to */
652 /* Note that cd will still be viewed as accessible, even if it */
653 /* refers to the object itself. */
654 GC_API void GC_register_finalizer_ignore_self
655 GC_PROTO((GC_PTR obj, GC_finalization_proc fn, GC_PTR cd,
656 GC_finalization_proc *ofn, GC_PTR *ocd));
657 GC_API void GC_debug_register_finalizer_ignore_self
658 GC_PROTO((GC_PTR obj, GC_finalization_proc fn, GC_PTR cd,
659 GC_finalization_proc *ofn, GC_PTR *ocd));
661 /* Another version of the above. It ignores all cycles. */
662 /* It should probably only be used by Java implementations. */
663 /* Note that cd will still be viewed as accessible, even if it */
664 /* refers to the object itself. */
665 GC_API void GC_register_finalizer_no_order
666 GC_PROTO((GC_PTR obj, GC_finalization_proc fn, GC_PTR cd,
667 GC_finalization_proc *ofn, GC_PTR *ocd));
668 GC_API void GC_debug_register_finalizer_no_order
669 GC_PROTO((GC_PTR obj, GC_finalization_proc fn, GC_PTR cd,
670 GC_finalization_proc *ofn, GC_PTR *ocd));
673 /* The following routine may be used to break cycles between */
674 /* finalizable objects, thus causing cyclic finalizable */
675 /* objects to be finalized in the correct order. Standard */
676 /* use involves calling GC_register_disappearing_link(&p), */
677 /* where p is a pointer that is not followed by finalization */
678 /* code, and should not be considered in determining */
679 /* finalization order. */
680 GC_API int GC_register_disappearing_link GC_PROTO((GC_PTR * /* link */));
681 /* Link should point to a field of a heap allocated */
682 /* object obj. *link will be cleared when obj is */
683 /* found to be inaccessible. This happens BEFORE any */
684 /* finalization code is invoked, and BEFORE any */
685 /* decisions about finalization order are made. */
686 /* This is useful in telling the finalizer that */
687 /* some pointers are not essential for proper */
688 /* finalization. This may avoid finalization cycles. */
689 /* Note that obj may be resurrected by another */
690 /* finalizer, and thus the clearing of *link may */
691 /* be visible to non-finalization code. */
692 /* There's an argument that an arbitrary action should */
693 /* be allowed here, instead of just clearing a pointer. */
694 /* But this causes problems if that action alters, or */
695 /* examines connectivity. */
696 /* Returns 1 if link was already registered, 0 */
698 /* Only exists for backward compatibility. See below: */
700 GC_API int GC_general_register_disappearing_link
701 GC_PROTO((GC_PTR * /* link */, GC_PTR obj));
702 /* A slight generalization of the above. *link is */
703 /* cleared when obj first becomes inaccessible. This */
704 /* can be used to implement weak pointers easily and */
705 /* safely. Typically link will point to a location */
706 /* holding a disguised pointer to obj. (A pointer */
707 /* inside an "atomic" object is effectively */
708 /* disguised.) In this way soft */
709 /* pointers are broken before any object */
710 /* reachable from them are finalized. Each link */
711 /* May be registered only once, i.e. with one obj */
712 /* value. This was added after a long email discussion */
713 /* with John Ellis. */
714 /* Obj must be a pointer to the first word of an object */
715 /* we allocated. It is unsafe to explicitly deallocate */
716 /* the object containing link. Explicitly deallocating */
717 /* obj may or may not cause link to eventually be */
719 GC_API int GC_unregister_disappearing_link GC_PROTO((GC_PTR * /* link */));
720 /* Returns 0 if link was not actually registered. */
721 /* Undoes a registration by either of the above two */
724 /* Returns !=0 if GC_invoke_finalizers has something to do. */
725 GC_API int GC_should_invoke_finalizers GC_PROTO((void));
727 GC_API int GC_invoke_finalizers GC_PROTO((void));
728 /* Run finalizers for all objects that are ready to */
729 /* be finalized. Return the number of finalizers */
730 /* that were run. Normally this is also called */
731 /* implicitly during some allocations. If */
732 /* GC-finalize_on_demand is nonzero, it must be called */
735 /* GC_set_warn_proc can be used to redirect or filter warning messages. */
736 /* p may not be a NULL pointer. */
737 typedef void (*GC_warn_proc) GC_PROTO((char *msg, GC_word arg));
738 GC_API GC_warn_proc GC_set_warn_proc GC_PROTO((GC_warn_proc p));
739 /* Returns old warning procedure. */
741 GC_API GC_word GC_set_free_space_divisor GC_PROTO((GC_word value));
742 /* Set free_space_divisor. See above for definition. */
743 /* Returns old value. */
745 /* The following is intended to be used by a higher level */
746 /* (e.g. Java-like) finalization facility. It is expected */
747 /* that finalization code will arrange for hidden pointers to */
748 /* disappear. Otherwise objects can be accessed after they */
749 /* have been collected. */
750 /* Note that putting pointers in atomic objects or in */
751 /* nonpointer slots of "typed" objects is equivalent to */
752 /* disguising them in this way, and may have other advantages. */
753 # if defined(I_HIDE_POINTERS) || defined(GC_I_HIDE_POINTERS)
754 typedef GC_word GC_hidden_pointer;
755 # define HIDE_POINTER(p) (~(GC_hidden_pointer)(p))
756 # define REVEAL_POINTER(p) ((GC_PTR)(HIDE_POINTER(p)))
757 /* Converting a hidden pointer to a real pointer requires verifying */
758 /* that the object still exists. This involves acquiring the */
759 /* allocator lock to avoid a race with the collector. */
760 # endif /* I_HIDE_POINTERS */
762 typedef GC_PTR (*GC_fn_type) GC_PROTO((GC_PTR client_data));
763 GC_API GC_PTR GC_call_with_alloc_lock
764 GC_PROTO((GC_fn_type fn, GC_PTR client_data));
766 /* The following routines are primarily intended for use with a */
767 /* preprocessor which inserts calls to check C pointer arithmetic. */
769 /* Check that p and q point to the same object. */
770 /* Fail conspicuously if they don't. */
771 /* Returns the first argument. */
772 /* Succeeds if neither p nor q points to the heap. */
773 /* May succeed if both p and q point to between heap objects. */
774 GC_API GC_PTR GC_same_obj GC_PROTO((GC_PTR p, GC_PTR q));
776 /* Checked pointer pre- and post- increment operations. Note that */
777 /* the second argument is in units of bytes, not multiples of the */
778 /* object size. This should either be invoked from a macro, or the */
779 /* call should be automatically generated. */
780 GC_API GC_PTR GC_pre_incr GC_PROTO((GC_PTR *p, size_t how_much));
781 GC_API GC_PTR GC_post_incr GC_PROTO((GC_PTR *p, size_t how_much));
783 /* Check that p is visible */
784 /* to the collector as a possibly pointer containing location. */
785 /* If it isn't fail conspicuously. */
786 /* Returns the argument in all cases. May erroneously succeed */
787 /* in hard cases. (This is intended for debugging use with */
788 /* untyped allocations. The idea is that it should be possible, though */
789 /* slow, to add such a call to all indirect pointer stores.) */
790 /* Currently useless for multithreaded worlds. */
791 GC_API GC_PTR GC_is_visible GC_PROTO((GC_PTR p));
793 /* Check that if p is a pointer to a heap page, then it points to */
794 /* a valid displacement within a heap object. */
795 /* Fail conspicuously if this property does not hold. */
796 /* Uninteresting with GC_all_interior_pointers. */
797 /* Always returns its argument. */
798 GC_API GC_PTR GC_is_valid_displacement GC_PROTO((GC_PTR p));
800 /* Safer, but slow, pointer addition. Probably useful mainly with */
801 /* a preprocessor. Useful only for heap pointers. */
803 # define GC_PTR_ADD3(x, n, type_of_result) \
804 ((type_of_result)GC_same_obj((x)+(n), (x)))
805 # define GC_PRE_INCR3(x, n, type_of_result) \
806 ((type_of_result)GC_pre_incr(&(x), (n)*sizeof(*x))
807 # define GC_POST_INCR2(x, type_of_result) \
808 ((type_of_result)GC_post_incr(&(x), sizeof(*x))
810 # define GC_PTR_ADD(x, n) \
811 GC_PTR_ADD3(x, n, typeof(x))
812 # define GC_PRE_INCR(x, n) \
813 GC_PRE_INCR3(x, n, typeof(x))
814 # define GC_POST_INCR(x, n) \
815 GC_POST_INCR3(x, typeof(x))
817 /* We can't do this right without typeof, which ANSI */
818 /* decided was not sufficiently useful. Repeatedly */
819 /* mentioning the arguments seems too dangerous to be */
820 /* useful. So does not casting the result. */
821 # define GC_PTR_ADD(x, n) ((x)+(n))
823 #else /* !GC_DEBUG */
824 # define GC_PTR_ADD3(x, n, type_of_result) ((x)+(n))
825 # define GC_PTR_ADD(x, n) ((x)+(n))
826 # define GC_PRE_INCR3(x, n, type_of_result) ((x) += (n))
827 # define GC_PRE_INCR(x, n) ((x) += (n))
828 # define GC_POST_INCR2(x, n, type_of_result) ((x)++)
829 # define GC_POST_INCR(x, n) ((x)++)
832 /* Safer assignment of a pointer to a nonstack location. */
835 # define GC_PTR_STORE(p, q) \
836 (*(void **)GC_is_visible(p) = GC_is_valid_displacement(q))
838 # define GC_PTR_STORE(p, q) \
839 (*(char **)GC_is_visible(p) = GC_is_valid_displacement(q))
841 #else /* !GC_DEBUG */
842 # define GC_PTR_STORE(p, q) *((p) = (q))
845 /* Fynctions called to report pointer checking errors */
846 GC_API void (*GC_same_obj_print_proc) GC_PROTO((GC_PTR p, GC_PTR q));
848 GC_API void (*GC_is_valid_displacement_print_proc)
849 GC_PROTO((GC_PTR p));
851 GC_API void (*GC_is_visible_print_proc)
852 GC_PROTO((GC_PTR p));
855 /* For pthread support, we generally need to intercept a number of */
856 /* thread library calls. We do that here by macro defining them. */
858 #if !defined(GC_USE_LD_WRAP) && \
859 (defined(GC_PTHREADS) || defined(GC_SOLARIS_THREADS))
860 # include "gc_pthread_redirects.h"
863 # if defined(PCR) || defined(GC_SOLARIS_THREADS) || \
864 defined(GC_PTHREADS) || defined(GC_WIN32_THREADS)
865 /* Any flavor of threads except SRC_M3. */
866 /* This returns a list of objects, linked through their first */
867 /* word. Its use can greatly reduce lock contention problems, since */
868 /* the allocation lock can be acquired and released many fewer times. */
869 /* lb must be large enough to hold the pointer field. */
870 /* It is used internally by gc_local_alloc.h, which provides a simpler */
871 /* programming interface on Linux. */
872 GC_PTR GC_malloc_many(size_t lb);
873 #define GC_NEXT(p) (*(GC_PTR *)(p)) /* Retrieve the next element */
874 /* in returned list. */
875 extern void GC_thr_init(); /* Needed for Solaris/X86 */
877 #endif /* THREADS && !SRC_M3 */
879 #if defined(GC_WIN32_THREADS) && !defined(__CYGWIN32__) && !defined(__CYGWIN__)
880 # include <windows.h>
883 * All threads must be created using GC_CreateThread, so that they will be
884 * recorded in the thread table. For backwards compatibility, this is not
885 * technically true if the GC is built as a dynamic library, since it can
886 * and does then use DllMain to keep track of thread creations. But new code
887 * should be built to call GC_CreateThread.
889 GC_API HANDLE GC_CreateThread(
890 LPSECURITY_ATTRIBUTES lpThreadAttributes,
891 DWORD dwStackSize, LPTHREAD_START_ROUTINE lpStartAddress,
892 LPVOID lpParameter, DWORD dwCreationFlags, LPDWORD lpThreadId );
894 # if defined(_WIN32_WCE)
896 * win32_threads.c implements the real WinMain, which will start a new thread
897 * to call GC_WinMain after initializing the garbage collector.
899 int WINAPI GC_WinMain(
901 HINSTANCE hPrevInstance,
906 # define WinMain GC_WinMain
907 # define CreateThread GC_CreateThread
909 # endif /* defined(_WIN32_WCE) */
911 #endif /* defined(GC_WIN32_THREADS) && !cygwin */
914 * If you are planning on putting
915 * the collector in a SunOS 5 dynamic library, you need to call GC_INIT()
916 * from the statically loaded program section.
917 * This circumvents a Solaris 2.X (X<=4) linker bug.
919 #if defined(sparc) || defined(__sparc)
920 # define GC_INIT() { extern end, etext; \
921 GC_noop(&end, &etext); }
923 # if defined(__CYGWIN32__) && defined(GC_DLL) || defined (_AIX)
925 * Similarly gnu-win32 DLLs need explicit initialization from
926 * the main program, as does AIX.
928 # define GC_INIT() { GC_add_roots(DATASTART, DATAEND); }
930 # if defined(__APPLE__) && defined(__MACH__)
931 # define GC_INIT() { GC_init(); }
938 #if !defined(_WIN32_WCE) \
939 && ((defined(_MSDOS) || defined(_MSC_VER)) && (_M_IX86 >= 300) \
940 || defined(_WIN32) && !defined(__CYGWIN32__) && !defined(__CYGWIN__))
941 /* win32S may not free all resources on process exit. */
942 /* This explicitly deallocates the heap. */
943 GC_API void GC_win32_free_heap ();
946 #if ( defined(_AMIGA) && !defined(GC_AMIGA_MAKINGLIB) )
947 /* Allocation really goes through GC_amiga_allocwrapper_do */
948 # include "gc_amiga_redirects.h"
951 #if defined(GC_REDIRECT_TO_LOCAL) && !defined(GC_LOCAL_ALLOC_H)
952 # include "gc_local_alloc.h"
956 } /* end of extern "C" */
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