| blob | cfc8658ac39962962f2b5b13717ec57cad9a0607 |
1 /*
2 * Copyright 1988, 1989 Hans-J. Boehm, Alan J. Demers
3 * Copyright (c) 1991-1995 by Xerox Corporation. All rights reserved.
4 * Copyright 1996-1999 by Silicon Graphics. All rights reserved.
5 * Copyright 1999 by Hewlett-Packard Company. All rights reserved.
6 *
7 * THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED
8 * OR IMPLIED. ANY USE IS AT YOUR OWN RISK.
9 *
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.
15 */
17 /*
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
26 * problems.
27 */
29 #ifndef _GC_H
31 # define _GC_H
33 /*
34 * As this header includes gc_config.h, preprocessor conflicts can occur with
35 * clients that include their own autoconf headers. The following #undef's
36 * work around some likely conflicts.
37 */
39 # ifdef PACKAGE_NAME
40 # undef PACKAGE_NAME
41 # endif
42 # ifdef PACKAGE_BUGREPORT
43 # undef PACKAGE_BUGREPORT
44 # endif
45 # ifdef PACKAGE_STRING
46 # undef PACKAGE_STRING
47 # endif
48 # ifdef PACKAGE_TARNAME
49 # undef PACKAGE_TARNAME
50 # endif
51 # ifdef PACKAGE_VERSION
52 # undef PACKAGE_VERSION
53 # endif
55 # include <gc_config.h>
58 # if defined(__STDC__) || defined(__cplusplus) || defined(_AIX)
59 # define GC_PROTO(args) args
61 # define GC_CONST const
62 # else
63 # define GC_PROTO(args) ()
65 # define GC_CONST
66 # endif
68 # ifdef __cplusplus
70 # endif
73 /* Define word and signed_word to be unsigned and signed types of the */
74 /* size as char * or void *. There seems to be no way to do this */
75 /* even semi-portably. The following is probably no better/worse */
76 /* than almost anything else. */
77 /* The ANSI standard suggests that size_t and ptr_diff_t might be */
78 /* better choices. But those had incorrect definitions on some older */
79 /* systems. Notably "typedef int size_t" is WRONG. */
80 #ifndef _WIN64
83 #else
84 /* Win64 isn't really supported yet, but this is the first step. And */
85 /* it might cause error messages to show up in more plausible places. */
86 /* This needs basetsd.h, which is included by windows.h. */
89 #endif
91 /* Public read-only variables */
94 /* Includes empty GCs at startup. */
97 /* multiprocessors. Currently set only */
98 /* implicitly if collector is built with */
99 /* -DPARALLEL_MARK and if either: */
100 /* Env variable GC_NPROC is set to > 1, or */
101 /* GC_NPROC is not set and this is an MP. */
102 /* If GC_parallel is set, incremental */
103 /* collection is only partially functional, */
104 /* and may not be desirable. */
107 /* Public R/W variables */
110 /* When there is insufficient memory to satisfy */
111 /* an allocation request, we return */
112 /* (*GC_oom_fn)(). By default this just */
113 /* returns 0. */
114 /* If it returns, it must return 0 or a valid */
115 /* pointer to a previously allocated heap */
116 /* object. */
119 /* Do not actually garbage collect, but simply */
120 /* report inaccessible memory that was not */
121 /* deallocated with GC_free. Initial value */
122 /* is determined by FIND_LEAK macro. */
125 /* Arrange for pointers to object interiors to */
126 /* be recognized as valid. May not be changed */
127 /* after GC initialization. */
128 /* Initial value is determined by */
129 /* -DALL_INTERIOR_POINTERS. */
130 /* Unless DONT_ADD_BYTE_AT_END is defined, this */
131 /* also affects whether sizes are increased by */
132 /* at least a byte to allow "off the end" */
133 /* pointer recognition. */
134 /* MUST BE 0 or 1. */
137 /* collector has been compiled with statistics */
138 /* enabled. This involves a performance cost, */
139 /* and is thus not the default. */
142 /* If nonzero, finalizers will only be run in */
143 /* response to an explicit GC_invoke_finalizers */
144 /* call. The default is determined by whether */
145 /* the FINALIZE_ON_DEMAND macro is defined */
146 /* when the collector is built. */
149 /* Mark objects reachable from finalizable */
150 /* objects in a separate postpass. This makes */
151 /* it a bit safer to use non-topologically- */
152 /* ordered finalization. Default value is */
153 /* determined by JAVA_FINALIZATION macro. */
156 /* Invoked by the collector when there are */
157 /* objects to be finalized. Invoked at most */
158 /* once per GC cycle. Never invoked unless */
159 /* GC_finalize_on_demand is set. */
160 /* Typically this will notify a finalization */
161 /* thread, which will call GC_invoke_finalizers */
162 /* in response. */
165 /* this overrides explicit GC_gcollect() calls. */
166 /* Used as a counter, so that nested enabling */
167 /* and disabling work correctly. Should */
168 /* normally be updated with GC_enable() and */
169 /* GC_disable() calls. */
170 /* Direct assignment to GC_dont_gc is */
171 /* deprecated. */
174 /* Dont expand heap unless explicitly requested */
175 /* or forced to. */
178 /* Causes the nonincremental collector to use the */
179 /* entire heap before collecting. This was the only */
180 /* option for GC versions < 5.0. This sometimes */
181 /* results in more large block fragmentation, since */
182 /* very larg blocks will tend to get broken up */
183 /* during each GC cycle. It is likely to result in a */
184 /* larger working set, but lower collection */
185 /* frequencies, and hence fewer instructions executed */
186 /* in the collector. */
189 /* full collections. Matters only if */
190 /* GC_incremental is set. */
191 /* Full collections are also triggered if */
192 /* the collector detects a substantial */
193 /* increase in the number of in-use heap */
194 /* blocks. Values in the tens are now */
195 /* perfectly reasonable, unlike for */
196 /* earlier GC versions. */
198 GC_API GC_word GC_non_gc_bytes;
199 /* Bytes not considered candidates for collection. */
200 /* Used only to control scheduling of collections. */
201 /* Updated by GC_malloc_uncollectable and GC_free. */
202 /* Wizards only. */
205 /* Don't register dynamic library data segments. */
206 /* Wizards only. Should be used only if the */
207 /* application explicitly registers all roots. */
208 /* In Microsoft Windows environments, this will */
209 /* usually also prevent registration of the */
210 /* main data segment as part of the root set. */
212 GC_API GC_word GC_free_space_divisor;
213 /* We try to make sure that we allocate at */
214 /* least N/GC_free_space_divisor bytes between */
215 /* collections, where N is the heap size plus */
216 /* a rough estimate of the root set size. */
217 /* Initially, GC_free_space_divisor = 3. */
218 /* Increasing its value will use less space */
219 /* but more collection time. Decreasing it */
220 /* will appreciably decrease collection time */
221 /* at the expense of space. */
222 /* GC_free_space_divisor = 1 will effectively */
223 /* disable collections. */
225 GC_API GC_word GC_max_retries;
226 /* The maximum number of GCs attempted before */
227 /* reporting out of memory after heap */
228 /* expansion fails. Initially 0. */
232 /* May be set in the client prior to */
233 /* calling any GC_ routines. This */
234 /* avoids some overhead, and */
235 /* potentially some signals that can */
236 /* confuse debuggers. Otherwise the */
237 /* collector attempts to set it */
238 /* automatically. */
239 /* For multithreaded code, this is the */
240 /* cold end of the stack for the */
241 /* primordial thread. */
244 /* initialization. Should be set only */
245 /* if the client wants a chance to */
246 /* manually initialize the root set */
247 /* before the first collection. */
248 /* Interferes with blacklisting. */
249 /* Wizards only. */
251 /* Public procedures */
253 /* Initialize the collector. This is only required when using thread-local
254 * allocation, since unlike the regular allocation routines, GC_local_malloc
255 * is not self-initializing. If you use GC_local_malloc you should arrange
256 * to call this somehow (e.g. from a constructor) before doing any allocation.
257 */
261 /* If incremental collection is enabled, */
262 /* We try to terminate collections */
263 /* after this many milliseconds. Not a */
264 /* hard time bound. Setting this to */
265 /* GC_TIME_UNLIMITED will essentially */
266 /* disable incremental collection while */
267 /* leaving generational collection */
268 /* enabled. */
269 # define GC_TIME_UNLIMITED 999999
270 /* Setting GC_time_limit to this value */
271 /* will disable the "pause time exceeded"*/
272 /* tests. */
274 /* Public procedures */
276 /* Initialize the collector. This is only required when using thread-local
277 * allocation, since unlike the regular allocation routines, GC_local_malloc
278 * is not self-initializing. If you use GC_local_malloc you should arrange
279 * to call this somehow (e.g. from a constructor) before doing any allocation.
280 * For win32 threads, it needs to be called explicitly.
281 */
284 /*
285 * general purpose allocation routines, with roughly malloc calling conv.
286 * The atomic versions promise that no relevant pointers are contained
287 * in the object. The nonatomic versions guarantee that the new object
288 * is cleared. GC_malloc_stubborn promises that no changes to the object
289 * will occur after GC_end_stubborn_change has been called on the
290 * result of GC_malloc_stubborn. GC_malloc_uncollectable allocates an object
291 * that is scanned for pointers to collectable objects, but is not itself
292 * collectable. The object is scanned even if it does not appear to
293 * be reachable. GC_malloc_uncollectable and GC_free called on the resulting
294 * object implicitly update GC_non_gc_bytes appropriately.
295 *
296 * Note that the GC_malloc_stubborn support is stubbed out by default
297 * starting in 6.0. GC_malloc_stubborn is an alias for GC_malloc unless
298 * the collector is built with STUBBORN_ALLOC defined.
299 */
305 /* The following is only defined if the library has been suitably */
306 /* compiled: */
309 /* Explicitly deallocate an object. Dangerous if used incorrectly. */
310 /* Requires a pointer to the base of an object. */
311 /* If the argument is stubborn, it should not be changeable when freed. */
312 /* An object should not be enable for finalization when it is */
313 /* explicitly deallocated. */
314 /* GC_free(0) is a no-op, as required by ANSI C for free. */
317 /*
318 * Stubborn objects may be changed only if the collector is explicitly informed.
319 * The collector is implicitly informed of coming change when such
320 * an object is first allocated. The following routines inform the
321 * collector that an object will no longer be changed, or that it will
322 * once again be changed. Only nonNIL pointer stores into the object
323 * are considered to be changes. The argument to GC_end_stubborn_change
324 * must be exacly the value returned by GC_malloc_stubborn or passed to
325 * GC_change_stubborn. (In the second case it may be an interior pointer
326 * within 512 bytes of the beginning of the objects.)
327 * There is a performance penalty for allowing more than
328 * one stubborn object to be changed at once, but it is acceptable to
329 * do so. The same applies to dropping stubborn objects that are still
330 * changeable.
331 */
335 /* Return a pointer to the base (lowest address) of an object given */
336 /* a pointer to a location within the object. */
337 /* I.e. map an interior pointer to the corresponding bas pointer. */
338 /* Note that with debugging allocation, this returns a pointer to the */
339 /* actual base of the object, i.e. the debug information, not to */
340 /* the base of the user object. */
341 /* Return 0 if displaced_pointer doesn't point to within a valid */
342 /* object. */
343 /* Note that a deallocated object in the garbage collected heap */
344 /* may be considered valid, even if it has been deallocated with */
345 /* GC_free. */
348 /* Given a pointer to the base of an object, return its size in bytes. */
349 /* The returned size may be slightly larger than what was originally */
350 /* requested. */
353 /* For compatibility with C library. This is occasionally faster than */
354 /* a malloc followed by a bcopy. But if you rely on that, either here */
355 /* or with the standard C library, your code is broken. In my */
356 /* opinion, it shouldn't have been invented, but now we're stuck. -HB */
357 /* The resulting object has the same kind as the original. */
358 /* If the argument is stubborn, the result will have changes enabled. */
359 /* It is an error to have changes enabled for the original object. */
360 /* Follows ANSI comventions for NULL old_object. */
361 GC_API GC_PTR GC_realloc
364 /* Explicitly increase the heap size. */
365 /* Returns 0 on failure, 1 on success. */
368 /* Limit the heap size to n bytes. Useful when you're debugging, */
369 /* especially on systems that don't handle running out of memory well. */
370 /* n == 0 ==> unbounded. This is the default. */
373 /* Inform the collector that a certain section of statically allocated */
374 /* memory contains no pointers to garbage collected memory. Thus it */
375 /* need not be scanned. This is sometimes important if the application */
376 /* maps large read/write files into the address space, which could be */
377 /* mistaken for dynamic library data segments on some systems. */
380 /* Clear the set of root segments. Wizards only. */
383 /* Add a root segment. Wizards only. */
387 /* Remove a root segment. Wizards only. */
391 /* Add a displacement to the set of those considered valid by the */
392 /* collector. GC_register_displacement(n) means that if p was returned */
393 /* by GC_malloc, then (char *)p + n will be considered to be a valid */
394 /* pointer to p. N must be small and less than the size of p. */
395 /* (All pointers to the interior of objects from the stack are */
396 /* considered valid in any case. This applies to heap objects and */
397 /* static data.) */
398 /* Preferably, this should be called before any other GC procedures. */
399 /* Calling it later adds to the probability of excess memory */
400 /* retention. */
401 /* This is a no-op if the collector has recognition of */
402 /* arbitrary interior pointers enabled, which is now the default. */
405 /* The following version should be used if any debugging allocation is */
406 /* being done. */
409 /* Explicitly trigger a full, world-stop collection. */
412 /* Trigger a full world-stopped collection. Abort the collection if */
413 /* and when stop_func returns a nonzero value. Stop_func will be */
414 /* called frequently, and should be reasonably fast. This works even */
415 /* if virtual dirty bits, and hence incremental collection is not */
416 /* available for this architecture. Collections can be aborted faster */
417 /* than normal pause times for incremental collection. However, */
418 /* aborted collections do no useful work; the next collection needs */
419 /* to start from the beginning. */
420 /* Return 0 if the collection was aborted, 1 if it succeeded. */
424 /* Return the number of bytes in the heap. Excludes collector private */
425 /* data structures. Includes empty blocks and fragmentation loss. */
426 /* Includes some pages that were allocated but never written. */
429 /* Return a lower bound on the number of free bytes in the heap. */
432 /* Return the number of bytes allocated since the last collection. */
435 /* Return the total number of bytes allocated in this process. */
436 /* Never decreases, except due to wrapping. */
439 /* Disable garbage collection. Even GC_gcollect calls will be */
440 /* ineffective. */
443 /* Reenable garbage collection. GC_disable() and GC_enable() calls */
444 /* nest. Garbage collection is enabled if the number of calls to both */
445 /* both functions is equal. */
448 /* Enable incremental/generational collection. */
449 /* Not advisable unless dirty bits are */
450 /* available or most heap objects are */
451 /* pointerfree(atomic) or immutable. */
452 /* Don't use in leak finding mode. */
453 /* Ignored if GC_dont_gc is true. */
454 /* Only the generational piece of this is */
455 /* functional if GC_parallel is TRUE */
456 /* or if GC_time_limit is GC_TIME_UNLIMITED. */
457 /* Causes GC_local_gcj_malloc() to revert to */
458 /* locked allocation. Must be called */
459 /* before any GC_local_gcj_malloc() calls. */
462 /* Does incremental mode write-protect pages? Returns zero or */
463 /* more of the following, or'ed together: */
465 #define GC_PROTECTS_PTRFREE_HEAP 2
469 #define GC_PROTECTS_NONE 0
472 /* Perform some garbage collection work, if appropriate. */
473 /* Return 0 if there is no more work to be done. */
474 /* Typically performs an amount of work corresponding roughly */
475 /* to marking from one page. May do more work if further */
476 /* progress requires it, e.g. if incremental collection is */
477 /* disabled. It is reasonable to call this in a wait loop */
478 /* until it returns 0. */
481 /* Allocate an object of size lb bytes. The client guarantees that */
482 /* as long as the object is live, it will be referenced by a pointer */
483 /* that points to somewhere within the first 256 bytes of the object. */
484 /* (This should normally be declared volatile to prevent the compiler */
485 /* from invalidating this assertion.) This routine is only useful */
486 /* if a large array is being allocated. It reduces the chance of */
487 /* accidentally retaining such an array as a result of scanning an */
488 /* integer that happens to be an address inside the array. (Actually, */
489 /* it reduces the chance of the allocator not finding space for such */
490 /* an array, since it will try hard to avoid introducing such a false */
491 /* reference.) On a SunOS 4.X or MS Windows system this is recommended */
492 /* for arrays likely to be larger than 100K or so. For other systems, */
493 /* or if the collector is not configured to recognize all interior */
494 /* pointers, the threshold is normally much higher. */
498 #if defined(__sgi) && !defined(__GNUC__) && _COMPILER_VERSION >= 720
499 # define GC_ADD_CALLER
500 # define GC_RETURN_ADDR (GC_word)__return_address
501 #endif
503 #ifdef __linux__
504 # include <features.h>
505 # if (__GLIBC__ == 2 && __GLIBC_MINOR__ >= 1 || __GLIBC__ > 2) \
506 && !defined(__ia64__)
507 # ifndef GC_HAVE_BUILTIN_BACKTRACE
508 # define GC_HAVE_BUILTIN_BACKTRACE
509 # endif
510 # endif
511 # if defined(__i386__) || defined(__x86_64__)
512 # define GC_CAN_SAVE_CALL_STACKS
513 # endif
514 #endif
516 #if defined(GC_HAVE_BUILTIN_BACKTRACE) && !defined(GC_CAN_SAVE_CALL_STACKS)
517 # define GC_CAN_SAVE_CALL_STACKS
518 #endif
520 #if defined(__sparc__)
521 # define GC_CAN_SAVE_CALL_STACKS
522 #endif
524 /* If we're on an a platform on which we can't save call stacks, but */
525 /* gcc is normally used, we go ahead and define GC_ADD_CALLER. */
526 /* We make this decision independent of whether gcc is actually being */
527 /* used, in order to keep the interface consistent, and allow mixing */
528 /* of compilers. */
529 /* This may also be desirable if it is possible but expensive to */
530 /* retrieve the call chain. */
531 #if (defined(__linux__) || defined(__NetBSD__) || defined(__OpenBSD__) \
532 || defined(__FreeBSD__)) & !defined(GC_CAN_SAVE_CALL_STACKS)
533 # define GC_ADD_CALLER
534 # if __GNUC__ >= 3 || (__GNUC__ == 2 && __GNUC_MINOR__ >= 95)
535 /* gcc knows how to retrieve return address, but we don't know */
536 /* how to generate call stacks. */
537 # define GC_RETURN_ADDR (GC_word)__builtin_return_address(0)
538 # else
539 /* Just pass 0 for gcc compatibility. */
540 # define GC_RETURN_ADDR 0
541 # endif
542 #endif
544 #ifdef GC_ADD_CALLER
545 # define GC_EXTRAS GC_RETURN_ADDR, __FILE__, __LINE__
546 # define GC_EXTRA_PARAMS GC_word ra, GC_CONST char * s, int i
547 #else
548 # define GC_EXTRAS __FILE__, __LINE__
549 # define GC_EXTRA_PARAMS GC_CONST char * s, int i
550 #endif
552 /* Debugging (annotated) allocation. GC_gcollect will check */
553 /* objects allocated in this way for overwrites, etc. */
554 GC_API GC_PTR GC_debug_malloc
556 GC_API GC_PTR GC_debug_malloc_atomic
558 GC_API GC_PTR GC_debug_malloc_uncollectable
560 GC_API GC_PTR GC_debug_malloc_stubborn
562 GC_API GC_PTR GC_debug_malloc_ignore_off_page
564 GC_API GC_PTR GC_debug_malloc_atomic_ignore_off_page
567 GC_API GC_PTR GC_debug_realloc
569 GC_EXTRA_PARAMS));
573 /* Routines that allocate objects with debug information (like the */
574 /* above), but just fill in dummy file and line number information. */
575 /* Thus they can serve as drop-in malloc/realloc replacements. This */
576 /* can be useful for two reasons: */
577 /* 1) It allows the collector to be built with DBG_HDRS_ALL defined */
578 /* even if some allocation calls come from 3rd party libraries */
579 /* that can't be recompiled. */
580 /* 2) On some platforms, the file and line information is redundant, */
581 /* since it can be reconstructed from a stack trace. On such */
582 /* platforms it may be more convenient not to recompile, e.g. for */
583 /* leak detection. This can be accomplished by instructing the */
584 /* linker to replace malloc/realloc with these. */
586 GC_API GC_PTR GC_debug_realloc_replacement
589 # ifdef GC_DEBUG
590 # define GC_MALLOC(sz) GC_debug_malloc(sz, GC_EXTRAS)
591 # define GC_MALLOC_ATOMIC(sz) GC_debug_malloc_atomic(sz, GC_EXTRAS)
592 # define GC_MALLOC_UNCOLLECTABLE(sz) \
593 GC_debug_malloc_uncollectable(sz, GC_EXTRAS)
594 # define GC_MALLOC_IGNORE_OFF_PAGE(sz) \
595 GC_debug_malloc_ignore_off_page(sz, GC_EXTRAS)
596 # define GC_MALLOC_ATOMIC_IGNORE_OFF_PAGE(sz) \
597 GC_debug_malloc_atomic_ignore_off_page(sz, GC_EXTRAS)
598 # define GC_REALLOC(old, sz) GC_debug_realloc(old, sz, GC_EXTRAS)
599 # define GC_FREE(p) GC_debug_free(p)
600 # define GC_REGISTER_FINALIZER(p, f, d, of, od) \
601 GC_debug_register_finalizer(p, f, d, of, od)
602 # define GC_REGISTER_FINALIZER_IGNORE_SELF(p, f, d, of, od) \
603 GC_debug_register_finalizer_ignore_self(p, f, d, of, od)
604 # define GC_REGISTER_FINALIZER_NO_ORDER(p, f, d, of, od) \
605 GC_debug_register_finalizer_no_order(p, f, d, of, od)
606 # define GC_MALLOC_STUBBORN(sz) GC_debug_malloc_stubborn(sz, GC_EXTRAS);
607 # define GC_CHANGE_STUBBORN(p) GC_debug_change_stubborn(p)
608 # define GC_END_STUBBORN_CHANGE(p) GC_debug_end_stubborn_change(p)
609 # define GC_GENERAL_REGISTER_DISAPPEARING_LINK(link, obj) \
610 GC_general_register_disappearing_link(link, GC_base(obj))
611 # define GC_REGISTER_DISPLACEMENT(n) GC_debug_register_displacement(n)
612 # else
613 # define GC_MALLOC(sz) GC_malloc(sz)
614 # define GC_MALLOC_ATOMIC(sz) GC_malloc_atomic(sz)
615 # define GC_MALLOC_UNCOLLECTABLE(sz) GC_malloc_uncollectable(sz)
616 # define GC_MALLOC_IGNORE_OFF_PAGE(sz) \
617 GC_malloc_ignore_off_page(sz)
618 # define GC_MALLOC_ATOMIC_IGNORE_OFF_PAGE(sz) \
619 GC_malloc_atomic_ignore_off_page(sz)
620 # define GC_REALLOC(old, sz) GC_realloc(old, sz)
621 # define GC_FREE(p) GC_free(p)
622 # define GC_REGISTER_FINALIZER(p, f, d, of, od) \
623 GC_register_finalizer(p, f, d, of, od)
624 # define GC_REGISTER_FINALIZER_IGNORE_SELF(p, f, d, of, od) \
625 GC_register_finalizer_ignore_self(p, f, d, of, od)
626 # define GC_REGISTER_FINALIZER_NO_ORDER(p, f, d, of, od) \
627 GC_register_finalizer_no_order(p, f, d, of, od)
628 # define GC_MALLOC_STUBBORN(sz) GC_malloc_stubborn(sz)
629 # define GC_CHANGE_STUBBORN(p) GC_change_stubborn(p)
630 # define GC_END_STUBBORN_CHANGE(p) GC_end_stubborn_change(p)
631 # define GC_GENERAL_REGISTER_DISAPPEARING_LINK(link, obj) \
632 GC_general_register_disappearing_link(link, obj)
633 # define GC_REGISTER_DISPLACEMENT(n) GC_register_displacement(n)
634 # endif
635 /* The following are included because they are often convenient, and */
636 /* reduce the chance for a misspecifed size argument. But calls may */
637 /* expand to something syntactically incorrect if t is a complicated */
638 /* type expression. */
639 # define GC_NEW(t) (t *)GC_MALLOC(sizeof (t))
640 # define GC_NEW_ATOMIC(t) (t *)GC_MALLOC_ATOMIC(sizeof (t))
641 # define GC_NEW_STUBBORN(t) (t *)GC_MALLOC_STUBBORN(sizeof (t))
642 # define GC_NEW_UNCOLLECTABLE(t) (t *)GC_MALLOC_UNCOLLECTABLE(sizeof (t))
644 /* Finalization. Some of these primitives are grossly unsafe. */
645 /* The idea is to make them both cheap, and sufficient to build */
646 /* a safer layer, closer to Modula-3, Java, or PCedar finalization. */
647 /* The interface represents my conclusions from a long discussion */
648 /* with Alan Demers, Dan Greene, Carl Hauser, Barry Hayes, */
649 /* Christian Jacobi, and Russ Atkinson. It's not perfect, and */
650 /* probably nobody else agrees with it. Hans-J. Boehm 3/13/92 */
654 GC_API void GC_register_finalizer
657 GC_API void GC_debug_register_finalizer
660 /* When obj is no longer accessible, invoke */
661 /* (*fn)(obj, cd). If a and b are inaccessible, and */
662 /* a points to b (after disappearing links have been */
663 /* made to disappear), then only a will be */
664 /* finalized. (If this does not create any new */
665 /* pointers to b, then b will be finalized after the */
666 /* next collection.) Any finalizable object that */
667 /* is reachable from itself by following one or more */
668 /* pointers will not be finalized (or collected). */
669 /* Thus cycles involving finalizable objects should */
670 /* be avoided, or broken by disappearing links. */
671 /* All but the last finalizer registered for an object */
672 /* is ignored. */
673 /* Finalization may be removed by passing 0 as fn. */
674 /* Finalizers are implicitly unregistered just before */
675 /* they are invoked. */
676 /* The old finalizer and client data are stored in */
677 /* *ofn and *ocd. */
678 /* Fn is never invoked on an accessible object, */
679 /* provided hidden pointers are converted to real */
680 /* pointers only if the allocation lock is held, and */
681 /* such conversions are not performed by finalization */
682 /* routines. */
683 /* If GC_register_finalizer is aborted as a result of */
684 /* a signal, the object may be left with no */
685 /* finalization, even if neither the old nor new */
686 /* finalizer were NULL. */
687 /* Obj should be the nonNULL starting address of an */
688 /* object allocated by GC_malloc or friends. */
689 /* Note that any garbage collectable object referenced */
690 /* by cd will be considered accessible until the */
691 /* finalizer is invoked. */
693 /* Another versions of the above follow. It ignores */
694 /* self-cycles, i.e. pointers from a finalizable object to */
695 /* itself. There is a stylistic argument that this is wrong, */
696 /* but it's unavoidable for C++, since the compiler may */
697 /* silently introduce these. It's also benign in that specific */
698 /* case. And it helps if finalizable objects are split to */
699 /* avoid cycles. */
700 /* Note that cd will still be viewed as accessible, even if it */
701 /* refers to the object itself. */
702 GC_API void GC_register_finalizer_ignore_self
705 GC_API void GC_debug_register_finalizer_ignore_self
709 /* Another version of the above. It ignores all cycles. */
710 /* It should probably only be used by Java implementations. */
711 /* Note that cd will still be viewed as accessible, even if it */
712 /* refers to the object itself. */
713 GC_API void GC_register_finalizer_no_order
716 GC_API void GC_debug_register_finalizer_no_order
721 /* The following routine may be used to break cycles between */
722 /* finalizable objects, thus causing cyclic finalizable */
723 /* objects to be finalized in the correct order. Standard */
724 /* use involves calling GC_register_disappearing_link(&p), */
725 /* where p is a pointer that is not followed by finalization */
726 /* code, and should not be considered in determining */
727 /* finalization order. */
729 /* Link should point to a field of a heap allocated */
730 /* object obj. *link will be cleared when obj is */
731 /* found to be inaccessible. This happens BEFORE any */
732 /* finalization code is invoked, and BEFORE any */
733 /* decisions about finalization order are made. */
734 /* This is useful in telling the finalizer that */
735 /* some pointers are not essential for proper */
736 /* finalization. This may avoid finalization cycles. */
737 /* Note that obj may be resurrected by another */
738 /* finalizer, and thus the clearing of *link may */
739 /* be visible to non-finalization code. */
740 /* There's an argument that an arbitrary action should */
741 /* be allowed here, instead of just clearing a pointer. */
742 /* But this causes problems if that action alters, or */
743 /* examines connectivity. */
744 /* Returns 1 if link was already registered, 0 */
745 /* otherwise. */
746 /* Only exists for backward compatibility. See below: */
748 GC_API int GC_general_register_disappearing_link
750 /* A slight generalization of the above. *link is */
751 /* cleared when obj first becomes inaccessible. This */
752 /* can be used to implement weak pointers easily and */
753 /* safely. Typically link will point to a location */
754 /* holding a disguised pointer to obj. (A pointer */
755 /* inside an "atomic" object is effectively */
756 /* disguised.) In this way soft */
757 /* pointers are broken before any object */
758 /* reachable from them are finalized. Each link */
759 /* May be registered only once, i.e. with one obj */
760 /* value. This was added after a long email discussion */
761 /* with John Ellis. */
762 /* Obj must be a pointer to the first word of an object */
763 /* we allocated. It is unsafe to explicitly deallocate */
764 /* the object containing link. Explicitly deallocating */
765 /* obj may or may not cause link to eventually be */
766 /* cleared. */
768 /* Returns 0 if link was not actually registered. */
769 /* Undoes a registration by either of the above two */
770 /* routines. */
772 /* Returns !=0 if GC_invoke_finalizers has something to do. */
776 /* Run finalizers for all objects that are ready to */
777 /* be finalized. Return the number of finalizers */
778 /* that were run. Normally this is also called */
779 /* implicitly during some allocations. If */
780 /* GC-finalize_on_demand is nonzero, it must be called */
781 /* explicitly. */
783 /* GC_set_warn_proc can be used to redirect or filter warning messages. */
784 /* p may not be a NULL pointer. */
787 /* Returns old warning procedure. */
790 /* Set free_space_divisor. See above for definition. */
791 /* Returns old value. */
793 /* The following is intended to be used by a higher level */
794 /* (e.g. Java-like) finalization facility. It is expected */
795 /* that finalization code will arrange for hidden pointers to */
796 /* disappear. Otherwise objects can be accessed after they */
797 /* have been collected. */
798 /* Note that putting pointers in atomic objects or in */
799 /* nonpointer slots of "typed" objects is equivalent to */
800 /* disguising them in this way, and may have other advantages. */
801 # if defined(I_HIDE_POINTERS) || defined(GC_I_HIDE_POINTERS)
803 # define HIDE_POINTER(p) (~(GC_hidden_pointer)(p))
804 # define REVEAL_POINTER(p) ((GC_PTR)(HIDE_POINTER(p)))
805 /* Converting a hidden pointer to a real pointer requires verifying */
806 /* that the object still exists. This involves acquiring the */
807 /* allocator lock to avoid a race with the collector. */
811 GC_API GC_PTR GC_call_with_alloc_lock
814 /* The following routines are primarily intended for use with a */
815 /* preprocessor which inserts calls to check C pointer arithmetic. */
816 /* They indicate failure by invoking the corresponding _print_proc. */
818 /* Check that p and q point to the same object. */
819 /* Fail conspicuously if they don't. */
820 /* Returns the first argument. */
821 /* Succeeds if neither p nor q points to the heap. */
822 /* May succeed if both p and q point to between heap objects. */
825 /* Checked pointer pre- and post- increment operations. Note that */
826 /* the second argument is in units of bytes, not multiples of the */
827 /* object size. This should either be invoked from a macro, or the */
828 /* call should be automatically generated. */
832 /* Check that p is visible */
833 /* to the collector as a possibly pointer containing location. */
834 /* If it isn't fail conspicuously. */
835 /* Returns the argument in all cases. May erroneously succeed */
836 /* in hard cases. (This is intended for debugging use with */
837 /* untyped allocations. The idea is that it should be possible, though */
838 /* slow, to add such a call to all indirect pointer stores.) */
839 /* Currently useless for multithreaded worlds. */
842 /* Check that if p is a pointer to a heap page, then it points to */
843 /* a valid displacement within a heap object. */
844 /* Fail conspicuously if this property does not hold. */
845 /* Uninteresting with GC_all_interior_pointers. */
846 /* Always returns its argument. */
849 /* Safer, but slow, pointer addition. Probably useful mainly with */
850 /* a preprocessor. Useful only for heap pointers. */
851 #ifdef GC_DEBUG
852 # define GC_PTR_ADD3(x, n, type_of_result) \
853 ((type_of_result)GC_same_obj((x)+(n), (x)))
854 # define GC_PRE_INCR3(x, n, type_of_result) \
855 ((type_of_result)GC_pre_incr(&(x), (n)*sizeof(*x))
856 # define GC_POST_INCR2(x, type_of_result) \
857 ((type_of_result)GC_post_incr(&(x), sizeof(*x))
858 # ifdef __GNUC__
859 # define GC_PTR_ADD(x, n) \
860 GC_PTR_ADD3(x, n, typeof(x))
861 # define GC_PRE_INCR(x, n) \
862 GC_PRE_INCR3(x, n, typeof(x))
863 # define GC_POST_INCR(x, n) \
864 GC_POST_INCR3(x, typeof(x))
865 # else
866 /* We can't do this right without typeof, which ANSI */
867 /* decided was not sufficiently useful. Repeatedly */
868 /* mentioning the arguments seems too dangerous to be */
869 /* useful. So does not casting the result. */
870 # define GC_PTR_ADD(x, n) ((x)+(n))
871 # endif
873 # define GC_PTR_ADD3(x, n, type_of_result) ((x)+(n))
874 # define GC_PTR_ADD(x, n) ((x)+(n))
875 # define GC_PRE_INCR3(x, n, type_of_result) ((x) += (n))
876 # define GC_PRE_INCR(x, n) ((x) += (n))
877 # define GC_POST_INCR2(x, n, type_of_result) ((x)++)
878 # define GC_POST_INCR(x, n) ((x)++)
879 #endif
881 /* Safer assignment of a pointer to a nonstack location. */
882 #ifdef GC_DEBUG
883 # if defined(__STDC__) || defined(_AIX)
884 # define GC_PTR_STORE(p, q) \
885 (*(void **)GC_is_visible(p) = GC_is_valid_displacement(q))
886 # else
887 # define GC_PTR_STORE(p, q) \
888 (*(char **)GC_is_visible(p) = GC_is_valid_displacement(q))
889 # endif
891 # define GC_PTR_STORE(p, q) *((p) = (q))
892 #endif
894 /* Functions called to report pointer checking errors */
904 /* For pthread support, we generally need to intercept a number of */
905 /* thread library calls. We do that here by macro defining them. */
907 #if !defined(GC_USE_LD_WRAP) && \
908 (defined(GC_PTHREADS) || defined(GC_SOLARIS_THREADS))
910 #endif
912 # if defined(PCR) || defined(GC_SOLARIS_THREADS) || \
913 defined(GC_PTHREADS) || defined(GC_WIN32_THREADS)
914 /* Any flavor of threads except SRC_M3. */
915 /* This returns a list of objects, linked through their first */
916 /* word. Its use can greatly reduce lock contention problems, since */
917 /* the allocation lock can be acquired and released many fewer times. */
918 /* lb must be large enough to hold the pointer field. */
919 /* It is used internally by gc_local_alloc.h, which provides a simpler */
920 /* programming interface on Linux. */
923 /* in returned list. */
928 #if defined(GC_WIN32_THREADS) && !defined(__CYGWIN32__) && !defined(__CYGWIN__)
929 # include <windows.h>
931 /*
932 * All threads must be created using GC_CreateThread, so that they will be
933 * recorded in the thread table. For backwards compatibility, this is not
934 * technically true if the GC is built as a dynamic library, since it can
935 * and does then use DllMain to keep track of thread creations. But new code
936 * should be built to call GC_CreateThread.
937 */
939 LPSECURITY_ATTRIBUTES lpThreadAttributes,
943 # if defined(_WIN32_WCE)
944 /*
945 * win32_threads.c implements the real WinMain, which will start a new thread
946 * to call GC_WinMain after initializing the garbage collector.
947 */
949 HINSTANCE hInstance,
950 HINSTANCE hPrevInstance,
951 LPWSTR lpCmdLine,
954 # ifndef GC_BUILD
955 # define WinMain GC_WinMain
956 # define CreateThread GC_CreateThread
957 # endif
962 /*
963 * Fully portable code should call GC_INIT() from the main program
964 * before making any other GC_ calls. On most platforms this is a
965 * no-op and the collector self-initializes. But a number of platforms
966 * make that too hard.
967 */
968 #if (defined(sparc) || defined(__sparc)) && defined(sun)
969 /*
970 * If you are planning on putting
971 * the collector in a SunOS 5 dynamic library, you need to call GC_INIT()
972 * from the statically loaded program section.
973 * This circumvents a Solaris 2.X (X<=4) linker bug.
974 */
975 # define GC_INIT() { extern end, etext; \
976 GC_noop(&end, &etext); }
977 #else
978 # if defined(__CYGWIN32__) || defined (_AIX)
979 /*
980 * Similarly gnu-win32 DLLs need explicit initialization from
981 * the main program, as does AIX.
982 */
983 # ifdef __CYGWIN32__
988 # define GC_MAX(x,y) ((x) > (y) ? (x) : (y))
989 # define GC_MIN(x,y) ((x) < (y) ? (x) : (y))
990 # define GC_DATASTART ((GC_PTR) GC_MIN(_data_start__, _bss_start__))
991 # define GC_DATAEND ((GC_PTR) GC_MAX(_data_end__, _bss_end__))
992 # ifdef GC_DLL
993 # define GC_INIT() { GC_add_roots(GC_DATASTART, GC_DATAEND); }
994 # else
995 # define GC_INIT()
996 # endif
997 # endif
998 # if defined(_AIX)
1000 # define GC_DATASTART ((GC_PTR)((ulong)_data))
1001 # define GC_DATAEND ((GC_PTR)((ulong)_end))
1002 # define GC_INIT() { GC_add_roots(GC_DATASTART, GC_DATAEND); }
1003 # endif
1004 # else
1005 # if defined(__APPLE__) && defined(__MACH__) || defined(GC_WIN32_THREADS)
1006 # define GC_INIT() { GC_init(); }
1007 # else
1008 # define GC_INIT()
1013 #if !defined(_WIN32_WCE) \
1014 && ((defined(_MSDOS) || defined(_MSC_VER)) && (_M_IX86 >= 300) \
1015 || defined(_WIN32) && !defined(__CYGWIN32__) && !defined(__CYGWIN__))
1016 /* win32S may not free all resources on process exit. */
1017 /* This explicitly deallocates the heap. */
1019 #endif
1021 #if ( defined(_AMIGA) && !defined(GC_AMIGA_MAKINGLIB) )
1022 /* Allocation really goes through GC_amiga_allocwrapper_do */
1024 #endif
1026 #if defined(GC_REDIRECT_TO_LOCAL) && !defined(GC_LOCAL_ALLOC_H)
1028 #endif
1030 #ifdef __cplusplus
1032 #endif