2 * Copyright 1988, 1989 Hans-J. Boehm, Alan J. Demers
3 * Copyright (c) 1991-1996 by Xerox Corporation. All rights reserved.
4 * Copyright (c) 1996-1999 by Silicon Graphics. All rights reserved.
5 * Copyright (C) 2007 Free Software Foundation, Inc
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.
17 #include "private/gc_pmark.h"
19 #ifndef GC_NO_FINALIZATION
21 /* Type of mark procedure used for marking from finalizable object. */
22 /* This procedure normally does not mark the object, only its */
24 typedef void (* finalization_mark_proc)(ptr_t /* finalizable_obj_ptr */);
26 #define HASH3(addr,size,log_size) \
27 ((((word)(addr) >> 3) ^ ((word)(addr) >> (3 + (log_size)))) \
29 #define HASH2(addr,log_size) HASH3(addr, 1 << (log_size), log_size)
31 struct hash_chain_entry {
33 struct hash_chain_entry * next;
36 STATIC struct disappearing_link {
37 struct hash_chain_entry prolog;
38 # define dl_hidden_link prolog.hidden_key
39 /* Field to be cleared. */
40 # define dl_next(x) (struct disappearing_link *)((x) -> prolog.next)
41 # define dl_set_next(x, y) \
42 (void)((x)->prolog.next = (struct hash_chain_entry *)(y))
44 word dl_hidden_obj; /* Pointer to object base */
47 STATIC struct dl_hashtbl_s {
48 struct disappearing_link **head;
51 } GC_dl_hashtbl = { /* head */ NULL, /* log_size */ -1, /* entries */ 0}
52 #ifndef GC_LONG_REFS_NOT_NEEDED
53 , GC_ll_hashtbl = { /* head */ NULL, /* log_size */ -1, /* entries */ 0}
54 #endif /* !GC_LONG_REFS_NOT_NEEDED */
57 STATIC struct finalizable_object {
58 struct hash_chain_entry prolog;
59 # define fo_hidden_base prolog.hidden_key
60 /* Pointer to object base. */
61 /* No longer hidden once object */
62 /* is on finalize_now queue. */
63 # define fo_next(x) (struct finalizable_object *)((x) -> prolog.next)
64 # define fo_set_next(x,y) ((x)->prolog.next = (struct hash_chain_entry *)(y))
65 GC_finalization_proc fo_fn; /* Finalizer. */
67 word fo_object_size; /* In bytes. */
68 finalization_mark_proc fo_mark_proc; /* Mark-through procedure */
71 STATIC struct finalizable_object * GC_finalize_now = 0;
72 /* List of objects that should be finalized now. */
74 static signed_word log_fo_table_size = -1;
76 GC_INNER void GC_push_finalizer_structures(void)
78 GC_ASSERT((word)&GC_dl_hashtbl.head % sizeof(word) == 0);
79 GC_ASSERT((word)&GC_fo_head % sizeof(word) == 0);
80 GC_ASSERT((word)&GC_finalize_now % sizeof(word) == 0);
82 #ifndef GC_LONG_REFS_NOT_NEEDED
83 GC_ASSERT((word)&GC_ll_hashtbl.head % sizeof(word) == 0);
84 GC_push_all((ptr_t)(&GC_ll_hashtbl.head),
85 (ptr_t)(&GC_ll_hashtbl.head) + sizeof(word));
86 #endif /* !GC_LONG_REFS_NOT_NEEDED */
88 GC_push_all((ptr_t)(&GC_dl_hashtbl.head),
89 (ptr_t)(&GC_dl_hashtbl.head) + sizeof(word));
90 GC_push_all((ptr_t)(&GC_fo_head), (ptr_t)(&GC_fo_head) + sizeof(word));
91 GC_push_all((ptr_t)(&GC_finalize_now),
92 (ptr_t)(&GC_finalize_now) + sizeof(word));
95 /* Double the size of a hash table. *size_ptr is the log of its current */
96 /* size. May be a no-op. */
97 /* *table is a pointer to an array of hash headers. If we succeed, we */
98 /* update both *table and *log_size_ptr. */
100 STATIC void GC_grow_table(struct hash_chain_entry ***table,
101 signed_word *log_size_ptr)
104 register struct hash_chain_entry *p;
105 signed_word log_old_size = *log_size_ptr;
106 signed_word log_new_size = log_old_size + 1;
107 word old_size = ((log_old_size == -1)? 0: (1 << log_old_size));
108 word new_size = (word)1 << log_new_size;
109 /* FIXME: Power of 2 size often gets rounded up to one more page. */
110 struct hash_chain_entry **new_table = (struct hash_chain_entry **)
111 GC_INTERNAL_MALLOC_IGNORE_OFF_PAGE(
112 (size_t)new_size * sizeof(struct hash_chain_entry *), NORMAL);
114 if (new_table == 0) {
116 ABORT("Insufficient space for initial table allocation");
121 for (i = 0; i < old_size; i++) {
124 ptr_t real_key = GC_REVEAL_POINTER(p -> hidden_key);
125 struct hash_chain_entry *next = p -> next;
126 size_t new_hash = HASH3(real_key, new_size, log_new_size);
128 p -> next = new_table[new_hash];
129 new_table[new_hash] = p;
133 *log_size_ptr = log_new_size;
137 GC_API int GC_CALL GC_register_disappearing_link(void * * link)
141 base = (ptr_t)GC_base(link);
143 ABORT("Bad arg to GC_register_disappearing_link");
144 return(GC_general_register_disappearing_link(link, base));
147 STATIC int GC_register_disappearing_link_inner(
148 struct dl_hashtbl_s *dl_hashtbl, void **link,
151 struct disappearing_link *curr_dl;
153 struct disappearing_link * new_dl;
157 GC_ASSERT(obj != NULL && GC_base_C(obj) == obj);
158 if (dl_hashtbl -> log_size == -1
159 || dl_hashtbl -> entries > ((word)1 << dl_hashtbl -> log_size)) {
160 GC_grow_table((struct hash_chain_entry ***)&dl_hashtbl -> head,
161 &dl_hashtbl -> log_size);
162 GC_COND_LOG_PRINTF("Grew dl table to %u entries\n",
163 1 << (unsigned)dl_hashtbl -> log_size);
165 index = HASH2(link, dl_hashtbl -> log_size);
166 for (curr_dl = dl_hashtbl -> head[index]; curr_dl != 0;
167 curr_dl = dl_next(curr_dl)) {
168 if (curr_dl -> dl_hidden_link == GC_HIDE_POINTER(link)) {
169 curr_dl -> dl_hidden_obj = GC_HIDE_POINTER(obj);
174 new_dl = (struct disappearing_link *)
175 GC_INTERNAL_MALLOC(sizeof(struct disappearing_link),NORMAL);
177 GC_oom_func oom_fn = GC_oom_fn;
179 new_dl = (struct disappearing_link *)
180 (*oom_fn)(sizeof(struct disappearing_link));
184 /* It's not likely we'll make it here, but ... */
186 /* Recalculate index since the table may grow. */
187 index = HASH2(link, dl_hashtbl -> log_size);
188 /* Check again that our disappearing link not in the table. */
189 for (curr_dl = dl_hashtbl -> head[index]; curr_dl != 0;
190 curr_dl = dl_next(curr_dl)) {
191 if (curr_dl -> dl_hidden_link == GC_HIDE_POINTER(link)) {
192 curr_dl -> dl_hidden_obj = GC_HIDE_POINTER(obj);
194 # ifndef DBG_HDRS_ALL
195 /* Free unused new_dl returned by GC_oom_fn() */
196 GC_free((void *)new_dl);
202 new_dl -> dl_hidden_obj = GC_HIDE_POINTER(obj);
203 new_dl -> dl_hidden_link = GC_HIDE_POINTER(link);
204 dl_set_next(new_dl, dl_hashtbl -> head[index]);
205 dl_hashtbl -> head[index] = new_dl;
206 dl_hashtbl -> entries++;
211 GC_API int GC_CALL GC_general_register_disappearing_link(void * * link,
214 if (((word)link & (ALIGNMENT-1)) != 0 || NULL == link)
215 ABORT("Bad arg to GC_general_register_disappearing_link");
216 return GC_register_disappearing_link_inner(&GC_dl_hashtbl, link, obj);
220 # define FREE_DL_ENTRY(curr_dl) dl_set_next(curr_dl, NULL)
222 # define FREE_DL_ENTRY(curr_dl) GC_free(curr_dl)
225 /* Unregisters given link and returns the link entry to free. */
226 /* Assume the lock is held. */
227 GC_INLINE struct disappearing_link *GC_unregister_disappearing_link_inner(
228 struct dl_hashtbl_s *dl_hashtbl, void **link)
230 struct disappearing_link *curr_dl;
231 struct disappearing_link *prev_dl = NULL;
232 size_t index = HASH2(link, dl_hashtbl->log_size);
234 for (curr_dl = dl_hashtbl -> head[index]; curr_dl;
235 curr_dl = dl_next(curr_dl)) {
236 if (curr_dl -> dl_hidden_link == GC_HIDE_POINTER(link)) {
237 /* Remove found entry from the table. */
238 if (NULL == prev_dl) {
239 dl_hashtbl -> head[index] = dl_next(curr_dl);
241 dl_set_next(prev_dl, dl_next(curr_dl));
243 dl_hashtbl -> entries--;
251 GC_API int GC_CALL GC_unregister_disappearing_link(void * * link)
253 struct disappearing_link *curr_dl;
256 if (((word)link & (ALIGNMENT-1)) != 0) return(0); /* Nothing to do. */
259 curr_dl = GC_unregister_disappearing_link_inner(&GC_dl_hashtbl, link);
261 if (NULL == curr_dl) return 0;
262 FREE_DL_ENTRY(curr_dl);
266 #ifndef GC_LONG_REFS_NOT_NEEDED
267 GC_API int GC_CALL GC_register_long_link(void * * link, const void * obj)
269 if (((word)link & (ALIGNMENT-1)) != 0 || NULL == link)
270 ABORT("Bad arg to GC_register_long_link");
271 return GC_register_disappearing_link_inner(&GC_ll_hashtbl, link, obj);
274 GC_API int GC_CALL GC_unregister_long_link(void * * link)
276 struct disappearing_link *curr_dl;
279 if (((word)link & (ALIGNMENT-1)) != 0) return(0); /* Nothing to do. */
282 curr_dl = GC_unregister_disappearing_link_inner(&GC_ll_hashtbl, link);
284 if (NULL == curr_dl) return 0;
285 FREE_DL_ENTRY(curr_dl);
288 #endif /* !GC_LONG_REFS_NOT_NEEDED */
290 #ifndef GC_MOVE_DISAPPEARING_LINK_NOT_NEEDED
291 /* Moves a link. Assume the lock is held. */
292 STATIC int GC_move_disappearing_link_inner(
293 struct dl_hashtbl_s *dl_hashtbl,
294 void **link, void **new_link)
296 struct disappearing_link *curr_dl, *prev_dl, *new_dl;
297 size_t curr_index, new_index;
298 word curr_hidden_link;
299 word new_hidden_link;
301 /* Find current link. */
302 curr_index = HASH2(link, dl_hashtbl -> log_size);
303 curr_hidden_link = GC_HIDE_POINTER(link);
305 for (curr_dl = dl_hashtbl -> head[curr_index]; curr_dl;
306 curr_dl = dl_next(curr_dl)) {
307 if (curr_dl -> dl_hidden_link == curr_hidden_link)
312 if (NULL == curr_dl) {
316 if (link == new_link) {
317 return GC_SUCCESS; /* Nothing to do. */
320 /* link found; now check new_link not present. */
321 new_index = HASH2(new_link, dl_hashtbl -> log_size);
322 new_hidden_link = GC_HIDE_POINTER(new_link);
323 for (new_dl = dl_hashtbl -> head[new_index]; new_dl;
324 new_dl = dl_next(new_dl)) {
325 if (new_dl -> dl_hidden_link == new_hidden_link) {
326 /* Target already registered; bail. */
331 /* Remove from old, add to new, update link. */
332 if (NULL == prev_dl) {
333 dl_hashtbl -> head[curr_index] = dl_next(curr_dl);
335 dl_set_next(prev_dl, dl_next(curr_dl));
337 curr_dl -> dl_hidden_link = new_hidden_link;
338 dl_set_next(curr_dl, dl_hashtbl -> head[new_index]);
339 dl_hashtbl -> head[new_index] = curr_dl;
343 GC_API int GC_CALL GC_move_disappearing_link(void **link, void **new_link)
348 if (((word)new_link & (ALIGNMENT-1)) != 0 || new_link == NULL)
349 ABORT("Bad new_link arg to GC_move_disappearing_link");
350 if (((word)link & (ALIGNMENT-1)) != 0)
351 return GC_NOT_FOUND; /* Nothing to do. */
354 result = GC_move_disappearing_link_inner(&GC_dl_hashtbl, link, new_link);
359 # ifndef GC_LONG_REFS_NOT_NEEDED
360 GC_API int GC_CALL GC_move_long_link(void **link, void **new_link)
365 if (((word)new_link & (ALIGNMENT-1)) != 0 || new_link == NULL)
366 ABORT("Bad new_link arg to GC_move_disappearing_link");
367 if (((word)link & (ALIGNMENT-1)) != 0)
368 return GC_NOT_FOUND; /* Nothing to do. */
371 result = GC_move_disappearing_link_inner(&GC_ll_hashtbl, link, new_link);
375 # endif /* !GC_LONG_REFS_NOT_NEEDED */
377 #endif /* !GC_MOVE_DISAPPEARING_LINK_NOT_NEEDED */
379 /* Possible finalization_marker procedures. Note that mark stack */
380 /* overflow is handled by the caller, and is not a disaster. */
381 STATIC void GC_normal_finalize_mark_proc(ptr_t p)
385 PUSH_OBJ(p, hhdr, GC_mark_stack_top,
386 &(GC_mark_stack[GC_mark_stack_size]));
389 /* This only pays very partial attention to the mark descriptor. */
390 /* It does the right thing for normal and atomic objects, and treats */
391 /* most others as normal. */
392 STATIC void GC_ignore_self_finalize_mark_proc(ptr_t p)
395 word descr = hhdr -> hb_descr;
399 ptr_t target_limit = p + hhdr -> hb_sz - 1;
401 if ((descr & GC_DS_TAGS) == GC_DS_LENGTH) {
402 scan_limit = p + descr - sizeof(word);
404 scan_limit = target_limit + 1 - sizeof(word);
406 for (q = p; (word)q <= (word)scan_limit; q += ALIGNMENT) {
408 if (r < (word)p || r > (word)target_limit) {
409 GC_PUSH_ONE_HEAP(r, q, GC_mark_stack_top);
414 STATIC void GC_null_finalize_mark_proc(ptr_t p GC_ATTR_UNUSED) {}
416 /* Possible finalization_marker procedures. Note that mark stack */
417 /* overflow is handled by the caller, and is not a disaster. */
419 /* GC_unreachable_finalize_mark_proc is an alias for normal marking, */
420 /* but it is explicitly tested for, and triggers different */
421 /* behavior. Objects registered in this way are not finalized */
422 /* if they are reachable by other finalizable objects, even if those */
423 /* other objects specify no ordering. */
424 STATIC void GC_unreachable_finalize_mark_proc(ptr_t p)
426 GC_normal_finalize_mark_proc(p);
429 /* Register a finalization function. See gc.h for details. */
430 /* The last parameter is a procedure that determines */
431 /* marking for finalization ordering. Any objects marked */
432 /* by that procedure will be guaranteed to not have been */
433 /* finalized when this finalizer is invoked. */
434 STATIC void GC_register_finalizer_inner(void * obj,
435 GC_finalization_proc fn, void *cd,
436 GC_finalization_proc *ofn, void **ocd,
437 finalization_mark_proc mp)
440 struct finalizable_object * curr_fo, * prev_fo;
442 struct finalizable_object *new_fo = 0;
443 hdr *hhdr = NULL; /* initialized to prevent warning. */
448 if (log_fo_table_size == -1
449 || GC_fo_entries > ((word)1 << log_fo_table_size)) {
450 GC_grow_table((struct hash_chain_entry ***)&GC_fo_head,
452 GC_COND_LOG_PRINTF("Grew fo table to %u entries\n",
453 1 << (unsigned)log_fo_table_size);
455 /* in the THREADS case we hold allocation lock. */
458 index = HASH2(base, log_fo_table_size);
460 curr_fo = GC_fo_head[index];
461 while (curr_fo != 0) {
462 GC_ASSERT(GC_size(curr_fo) >= sizeof(struct finalizable_object));
463 if (curr_fo -> fo_hidden_base == GC_HIDE_POINTER(base)) {
464 /* Interruption by a signal in the middle of this */
465 /* should be safe. The client may see only *ocd */
466 /* updated, but we'll declare that to be his problem. */
467 if (ocd) *ocd = (void *) (curr_fo -> fo_client_data);
468 if (ofn) *ofn = curr_fo -> fo_fn;
469 /* Delete the structure for base. */
471 GC_fo_head[index] = fo_next(curr_fo);
473 fo_set_next(prev_fo, fo_next(curr_fo));
477 /* May not happen if we get a signal. But a high */
478 /* estimate will only make the table larger than */
480 # if !defined(THREADS) && !defined(DBG_HDRS_ALL)
481 GC_free((void *)curr_fo);
484 curr_fo -> fo_fn = fn;
485 curr_fo -> fo_client_data = (ptr_t)cd;
486 curr_fo -> fo_mark_proc = mp;
487 /* Reinsert it. We deleted it first to maintain */
488 /* consistency in the event of a signal. */
490 GC_fo_head[index] = curr_fo;
492 fo_set_next(prev_fo, curr_fo);
496 # ifndef DBG_HDRS_ALL
497 if (EXPECT(new_fo != 0, FALSE)) {
498 /* Free unused new_fo returned by GC_oom_fn() */
499 GC_free((void *)new_fo);
505 curr_fo = fo_next(curr_fo);
507 if (EXPECT(new_fo != 0, FALSE)) {
508 /* new_fo is returned by GC_oom_fn(), so fn != 0 and hhdr != 0. */
518 if (EXPECT(0 == hhdr, FALSE)) {
519 /* We won't collect it, hence finalizer wouldn't be run. */
525 new_fo = (struct finalizable_object *)
526 GC_INTERNAL_MALLOC(sizeof(struct finalizable_object),NORMAL);
527 if (EXPECT(new_fo != 0, TRUE))
531 new_fo = (struct finalizable_object *)
532 (*oom_fn)(sizeof(struct finalizable_object));
534 /* No enough memory. *ocd and *ofn remains unchanged. */
537 /* It's not likely we'll make it here, but ... */
539 /* Recalculate index since the table may grow and */
540 /* check again that our finalizer is not in the table. */
542 GC_ASSERT(GC_size(new_fo) >= sizeof(struct finalizable_object));
545 new_fo -> fo_hidden_base = GC_HIDE_POINTER(base);
546 new_fo -> fo_fn = fn;
547 new_fo -> fo_client_data = (ptr_t)cd;
548 new_fo -> fo_object_size = hhdr -> hb_sz;
549 new_fo -> fo_mark_proc = mp;
550 fo_set_next(new_fo, GC_fo_head[index]);
552 GC_fo_head[index] = new_fo;
556 GC_API void GC_CALL GC_register_finalizer(void * obj,
557 GC_finalization_proc fn, void * cd,
558 GC_finalization_proc *ofn, void ** ocd)
560 GC_register_finalizer_inner(obj, fn, cd, ofn,
561 ocd, GC_normal_finalize_mark_proc);
564 GC_API void GC_CALL GC_register_finalizer_ignore_self(void * obj,
565 GC_finalization_proc fn, void * cd,
566 GC_finalization_proc *ofn, void ** ocd)
568 GC_register_finalizer_inner(obj, fn, cd, ofn,
569 ocd, GC_ignore_self_finalize_mark_proc);
572 GC_API void GC_CALL GC_register_finalizer_no_order(void * obj,
573 GC_finalization_proc fn, void * cd,
574 GC_finalization_proc *ofn, void ** ocd)
576 GC_register_finalizer_inner(obj, fn, cd, ofn,
577 ocd, GC_null_finalize_mark_proc);
580 static GC_bool need_unreachable_finalization = FALSE;
581 /* Avoid the work if this isn't used. */
583 GC_API void GC_CALL GC_register_finalizer_unreachable(void * obj,
584 GC_finalization_proc fn, void * cd,
585 GC_finalization_proc *ofn, void ** ocd)
587 need_unreachable_finalization = TRUE;
588 GC_ASSERT(GC_java_finalization);
589 GC_register_finalizer_inner(obj, fn, cd, ofn,
590 ocd, GC_unreachable_finalize_mark_proc);
594 STATIC void GC_dump_finalization_links(struct dl_hashtbl_s* dl_hashtbl)
596 struct disappearing_link * curr_dl;
597 ptr_t real_ptr, real_link;
598 size_t dl_size = dl_hashtbl -> log_size == -1 ? 0 :
599 1 << dl_hashtbl -> log_size;
602 for (i = 0; i < dl_size; i++) {
603 for (curr_dl = dl_hashtbl -> head[i]; curr_dl != 0;
604 curr_dl = dl_next(curr_dl)) {
605 real_ptr = GC_REVEAL_POINTER(curr_dl -> dl_hidden_obj);
606 real_link = GC_REVEAL_POINTER(curr_dl -> dl_hidden_link);
607 GC_printf("Object: %p, Link:%p\n", real_ptr, real_link);
612 void GC_dump_finalization(void)
614 struct finalizable_object * curr_fo;
615 size_t fo_size = log_fo_table_size == -1 ? 0 : 1 << log_fo_table_size;
619 GC_printf("Disappearing short links:\n");
620 GC_dump_finalization_links(&GC_dl_hashtbl);
621 #ifndef GC_LONG_REFS_NOT_NEEDED
622 GC_printf("Disappearing long links:\n");
623 GC_dump_finalization_links(&GC_ll_hashtbl);
624 #endif /* !GC_LONG_REFS_NOT_NEEDED */
625 GC_printf("Finalizers:\n");
626 for (i = 0; i < fo_size; i++) {
627 for (curr_fo = GC_fo_head[i]; curr_fo != 0;
628 curr_fo = fo_next(curr_fo)) {
629 real_ptr = GC_REVEAL_POINTER(curr_fo -> fo_hidden_base);
630 GC_printf("Finalizable object: %p\n", real_ptr);
634 #endif /* !NO_DEBUGGING */
637 /* for stats printing */
638 STATIC word GC_old_dl_entries = 0, GC_old_ll_entries = 0;
642 /* Global variables to minimize the level of recursion when a client */
643 /* finalizer allocates memory. */
644 STATIC int GC_finalizer_nested = 0;
645 /* Only the lowest byte is used, the rest is */
646 /* padding for proper global data alignment */
647 /* required for some compilers (like Watcom). */
648 STATIC unsigned GC_finalizer_skipped = 0;
650 /* Checks and updates the level of finalizers recursion. */
651 /* Returns NULL if GC_invoke_finalizers() should not be called by the */
652 /* collector (to minimize the risk of a deep finalizers recursion), */
653 /* otherwise returns a pointer to GC_finalizer_nested. */
654 STATIC unsigned char *GC_check_finalizer_nested(void)
656 unsigned nesting_level = *(unsigned char *)&GC_finalizer_nested;
658 /* We are inside another GC_invoke_finalizers(). */
659 /* Skip some implicitly-called GC_invoke_finalizers() */
660 /* depending on the nesting (recursion) level. */
661 if (++GC_finalizer_skipped < (1U << nesting_level)) return NULL;
662 GC_finalizer_skipped = 0;
664 *(char *)&GC_finalizer_nested = (char)(nesting_level + 1);
665 return (unsigned char *)&GC_finalizer_nested;
669 #define ITERATE_DL_HASHTBL_BEGIN(dl_hashtbl, curr_dl, prev_dl) \
672 size_t dl_size = dl_hashtbl->log_size == -1 ? 0 : \
673 1 << dl_hashtbl->log_size; \
674 for (i = 0; i < dl_size; i++) { \
675 curr_dl = dl_hashtbl -> head[i]; \
679 #define ITERATE_DL_HASHTBL_END(curr_dl, prev_dl) \
681 curr_dl = dl_next(curr_dl); \
686 #define DELETE_DL_HASHTBL_ENTRY(dl_hashtbl, curr_dl, prev_dl, next_dl) \
688 next_dl = dl_next(curr_dl); \
689 if (NULL == prev_dl) { \
690 dl_hashtbl -> head[i] = next_dl; \
692 dl_set_next(prev_dl, next_dl); \
694 GC_clear_mark_bit(curr_dl); \
695 dl_hashtbl -> entries--; \
700 GC_INLINE void GC_make_disappearing_links_disappear(
701 struct dl_hashtbl_s* dl_hashtbl)
703 struct disappearing_link *curr, *prev, *next;
704 ptr_t real_ptr, real_link;
706 ITERATE_DL_HASHTBL_BEGIN(dl_hashtbl, curr, prev)
707 real_ptr = GC_REVEAL_POINTER(curr -> dl_hidden_obj);
708 real_link = GC_REVEAL_POINTER(curr -> dl_hidden_link);
709 if (!GC_is_marked(real_ptr)) {
710 *(word *)real_link = 0;
711 GC_clear_mark_bit(curr);
712 DELETE_DL_HASHTBL_ENTRY(dl_hashtbl, curr, prev, next);
714 ITERATE_DL_HASHTBL_END(curr, prev)
717 GC_INLINE void GC_remove_dangling_disappearing_links(
718 struct dl_hashtbl_s* dl_hashtbl)
720 struct disappearing_link *curr, *prev, *next;
723 ITERATE_DL_HASHTBL_BEGIN(dl_hashtbl, curr, prev)
724 real_link = GC_base(GC_REVEAL_POINTER(curr -> dl_hidden_link));
725 if (NULL != real_link && !GC_is_marked(real_link)) {
726 GC_clear_mark_bit(curr);
727 DELETE_DL_HASHTBL_ENTRY(dl_hashtbl, curr, prev, next);
729 ITERATE_DL_HASHTBL_END(curr, prev)
732 /* Called with held lock (but the world is running). */
733 /* Cause disappearing links to disappear and unreachable objects to be */
734 /* enqueued for finalization. */
735 GC_INNER void GC_finalize(void)
737 struct finalizable_object * curr_fo, * prev_fo, * next_fo;
740 size_t fo_size = log_fo_table_size == -1 ? 0 : 1 << log_fo_table_size;
742 # ifndef SMALL_CONFIG
743 /* Save current GC_[dl/ll]_entries value for stats printing */
744 GC_old_dl_entries = GC_dl_hashtbl.entries;
745 # ifndef GC_LONG_REFS_NOT_NEEDED
746 GC_old_ll_entries = GC_ll_hashtbl.entries;
747 # endif /* !GC_LONG_REFS_NOT_NEEDED */
750 GC_make_disappearing_links_disappear(&GC_dl_hashtbl);
752 /* Mark all objects reachable via chains of 1 or more pointers */
753 /* from finalizable objects. */
754 GC_ASSERT(GC_mark_state == MS_NONE);
755 for (i = 0; i < fo_size; i++) {
756 for (curr_fo = GC_fo_head[i]; curr_fo != 0;
757 curr_fo = fo_next(curr_fo)) {
758 GC_ASSERT(GC_size(curr_fo) >= sizeof(struct finalizable_object));
759 real_ptr = GC_REVEAL_POINTER(curr_fo -> fo_hidden_base);
760 if (!GC_is_marked(real_ptr)) {
761 GC_MARKED_FOR_FINALIZATION(real_ptr);
762 GC_MARK_FO(real_ptr, curr_fo -> fo_mark_proc);
763 if (GC_is_marked(real_ptr)) {
764 WARN("Finalization cycle involving %p\n", real_ptr);
769 /* Enqueue for finalization all objects that are still */
771 GC_bytes_finalized = 0;
772 for (i = 0; i < fo_size; i++) {
773 curr_fo = GC_fo_head[i];
775 while (curr_fo != 0) {
776 real_ptr = GC_REVEAL_POINTER(curr_fo -> fo_hidden_base);
777 if (!GC_is_marked(real_ptr)) {
778 if (!GC_java_finalization) {
779 GC_set_mark_bit(real_ptr);
781 /* Delete from hash table */
782 next_fo = fo_next(curr_fo);
784 GC_fo_head[i] = next_fo;
786 fo_set_next(prev_fo, next_fo);
789 /* Add to list of objects awaiting finalization. */
790 fo_set_next(curr_fo, GC_finalize_now);
791 GC_finalize_now = curr_fo;
792 /* unhide object pointer so any future collections will */
794 curr_fo -> fo_hidden_base =
795 (word)GC_REVEAL_POINTER(curr_fo -> fo_hidden_base);
796 GC_bytes_finalized +=
797 curr_fo -> fo_object_size
798 + sizeof(struct finalizable_object);
799 GC_ASSERT(GC_is_marked(GC_base(curr_fo)));
803 curr_fo = fo_next(curr_fo);
808 if (GC_java_finalization) {
809 /* make sure we mark everything reachable from objects finalized
810 using the no_order mark_proc */
811 for (curr_fo = GC_finalize_now;
812 curr_fo != NULL; curr_fo = fo_next(curr_fo)) {
813 real_ptr = (ptr_t)curr_fo -> fo_hidden_base;
814 if (!GC_is_marked(real_ptr)) {
815 if (curr_fo -> fo_mark_proc == GC_null_finalize_mark_proc) {
816 GC_MARK_FO(real_ptr, GC_normal_finalize_mark_proc);
818 if (curr_fo -> fo_mark_proc != GC_unreachable_finalize_mark_proc) {
819 GC_set_mark_bit(real_ptr);
824 /* now revive finalize-when-unreachable objects reachable from
825 other finalizable objects */
826 if (need_unreachable_finalization) {
827 curr_fo = GC_finalize_now;
829 while (curr_fo != 0) {
830 next_fo = fo_next(curr_fo);
831 if (curr_fo -> fo_mark_proc == GC_unreachable_finalize_mark_proc) {
832 real_ptr = (ptr_t)curr_fo -> fo_hidden_base;
833 if (!GC_is_marked(real_ptr)) {
834 GC_set_mark_bit(real_ptr);
837 GC_finalize_now = next_fo;
839 fo_set_next(prev_fo, next_fo);
841 curr_fo -> fo_hidden_base =
842 GC_HIDE_POINTER(curr_fo -> fo_hidden_base);
843 GC_bytes_finalized -=
844 curr_fo->fo_object_size + sizeof(struct finalizable_object);
846 i = HASH2(real_ptr, log_fo_table_size);
847 fo_set_next (curr_fo, GC_fo_head[i]);
849 GC_fo_head[i] = curr_fo;
859 GC_remove_dangling_disappearing_links(&GC_dl_hashtbl);
861 # ifndef GC_LONG_REFS_NOT_NEEDED
862 GC_make_disappearing_links_disappear(&GC_ll_hashtbl);
863 GC_remove_dangling_disappearing_links(&GC_ll_hashtbl);
864 # endif /* !GC_LONG_REFS_NOT_NEEDED */
867 /* Don't prevent running finalizers if there has been an allocation */
868 /* failure recently. */
870 GC_reset_finalizer_nested();
872 GC_finalizer_nested = 0;
877 #ifndef JAVA_FINALIZATION_NOT_NEEDED
879 /* Enqueue all remaining finalizers to be run - Assumes lock is held. */
880 STATIC void GC_enqueue_all_finalizers(void)
882 struct finalizable_object * curr_fo, * prev_fo, * next_fo;
887 fo_size = log_fo_table_size == -1 ? 0 : 1 << log_fo_table_size;
888 GC_bytes_finalized = 0;
889 for (i = 0; i < fo_size; i++) {
890 curr_fo = GC_fo_head[i];
892 while (curr_fo != 0) {
893 real_ptr = GC_REVEAL_POINTER(curr_fo -> fo_hidden_base);
894 GC_MARK_FO(real_ptr, GC_normal_finalize_mark_proc);
895 GC_set_mark_bit(real_ptr);
897 /* Delete from hash table */
898 next_fo = fo_next(curr_fo);
900 GC_fo_head[i] = next_fo;
902 fo_set_next(prev_fo, next_fo);
906 /* Add to list of objects awaiting finalization. */
907 fo_set_next(curr_fo, GC_finalize_now);
908 GC_finalize_now = curr_fo;
910 /* unhide object pointer so any future collections will */
912 curr_fo -> fo_hidden_base =
913 (word)GC_REVEAL_POINTER(curr_fo -> fo_hidden_base);
914 GC_bytes_finalized +=
915 curr_fo -> fo_object_size + sizeof(struct finalizable_object);
921 /* Invoke all remaining finalizers that haven't yet been run.
922 * This is needed for strict compliance with the Java standard,
923 * which can make the runtime guarantee that all finalizers are run.
924 * Unfortunately, the Java standard implies we have to keep running
925 * finalizers until there are no more left, a potential infinite loop.
927 * Note that this is even more dangerous than the usual Java
928 * finalizers, in that objects reachable from static variables
929 * may have been finalized when these finalizers are run.
930 * Finalizers run at this point must be prepared to deal with a
931 * mostly broken world.
932 * This routine is externally callable, so is called without
933 * the allocation lock.
935 GC_API void GC_CALL GC_finalize_all(void)
940 while (GC_fo_entries > 0) {
941 GC_enqueue_all_finalizers();
943 GC_invoke_finalizers();
944 /* Running the finalizers in this thread is arguably not a good */
945 /* idea when we should be notifying another thread to run them. */
946 /* But otherwise we don't have a great way to wait for them to */
953 #endif /* !JAVA_FINALIZATION_NOT_NEEDED */
955 /* Returns true if it is worth calling GC_invoke_finalizers. (Useful if */
956 /* finalizers can only be called from some kind of `safe state' and */
957 /* getting into that safe state is expensive.) */
958 GC_API int GC_CALL GC_should_invoke_finalizers(void)
960 return GC_finalize_now != 0;
963 /* Invoke finalizers for all objects that are ready to be finalized. */
964 /* Should be called without allocation lock. */
965 GC_API int GC_CALL GC_invoke_finalizers(void)
967 struct finalizable_object * curr_fo;
969 word bytes_freed_before = 0; /* initialized to prevent warning. */
972 while (GC_finalize_now != 0) {
977 bytes_freed_before = GC_bytes_freed;
978 /* Don't do this outside, since we need the lock. */
980 curr_fo = GC_finalize_now;
982 if (curr_fo != 0) GC_finalize_now = fo_next(curr_fo);
984 if (curr_fo == 0) break;
986 GC_finalize_now = fo_next(curr_fo);
988 fo_set_next(curr_fo, 0);
989 (*(curr_fo -> fo_fn))((ptr_t)(curr_fo -> fo_hidden_base),
990 curr_fo -> fo_client_data);
991 curr_fo -> fo_client_data = 0;
994 /* This is probably a bad idea. It throws off accounting if */
995 /* nearly all objects are finalizable. O.w. it shouldn't */
997 GC_free((void *)curr_fo);
1000 /* bytes_freed_before is initialized whenever count != 0 */
1001 if (count != 0 && bytes_freed_before != GC_bytes_freed) {
1003 GC_finalizer_bytes_freed += (GC_bytes_freed - bytes_freed_before);
1009 static GC_word last_finalizer_notification = 0;
1011 GC_INNER void GC_notify_or_invoke_finalizers(void)
1013 GC_finalizer_notifier_proc notifier_fn = 0;
1014 # if defined(KEEP_BACK_PTRS) || defined(MAKE_BACK_GRAPH)
1015 static word last_back_trace_gc_no = 1; /* Skip first one. */
1019 # if defined(THREADS) && !defined(KEEP_BACK_PTRS) \
1020 && !defined(MAKE_BACK_GRAPH)
1021 /* Quick check (while unlocked) for an empty finalization queue. */
1022 if (GC_finalize_now == 0) return;
1026 /* This is a convenient place to generate backtraces if appropriate, */
1027 /* since that code is not callable with the allocation lock. */
1028 # if defined(KEEP_BACK_PTRS) || defined(MAKE_BACK_GRAPH)
1029 if (GC_gc_no > last_back_trace_gc_no) {
1030 # ifdef KEEP_BACK_PTRS
1032 /* Stops when GC_gc_no wraps; that's OK. */
1033 last_back_trace_gc_no = (word)(-1); /* disable others. */
1034 for (i = 0; i < GC_backtraces; ++i) {
1035 /* FIXME: This tolerates concurrent heap mutation, */
1036 /* which may cause occasional mysterious results. */
1037 /* We need to release the GC lock, since GC_print_callers */
1038 /* acquires it. It probably shouldn't. */
1040 GC_generate_random_backtrace_no_gc();
1043 last_back_trace_gc_no = GC_gc_no;
1045 # ifdef MAKE_BACK_GRAPH
1046 if (GC_print_back_height) {
1048 GC_print_back_graph_stats();
1054 if (GC_finalize_now == 0) {
1059 if (!GC_finalize_on_demand) {
1060 unsigned char *pnested = GC_check_finalizer_nested();
1062 /* Skip GC_invoke_finalizers() if nested */
1063 if (pnested != NULL) {
1064 (void) GC_invoke_finalizers();
1065 *pnested = 0; /* Reset since no more finalizers. */
1067 GC_ASSERT(GC_finalize_now == 0);
1068 # endif /* Otherwise GC can run concurrently and add more */
1073 /* These variables require synchronization to avoid data races. */
1074 if (last_finalizer_notification != GC_gc_no) {
1075 last_finalizer_notification = GC_gc_no;
1076 notifier_fn = GC_finalizer_notifier;
1079 if (notifier_fn != 0)
1080 (*notifier_fn)(); /* Invoke the notifier */
1083 #ifndef SMALL_CONFIG
1084 GC_INNER void GC_print_finalization_stats(void)
1086 struct finalizable_object *fo = GC_finalize_now;
1087 unsigned long ready = 0;
1089 # ifndef GC_LONG_REFS_NOT_NEEDED
1091 "%lu finalization table entries; "
1092 "%lu short/%lu long disappearing links alive\n",
1093 (unsigned long)GC_fo_entries,
1094 (unsigned long)GC_dl_hashtbl.entries,
1095 (unsigned long)GC_ll_hashtbl.entries);
1096 for (; 0 != fo; fo = fo_next(fo)) ++ready;
1097 GC_log_printf("%lu objects are ready for finalization; "
1098 "%ld short/%ld long links cleared\n",
1100 (long)GC_old_dl_entries - (long)GC_dl_hashtbl.entries,
1101 (long)GC_old_ll_entries - (long)GC_ll_hashtbl.entries);
1102 # else /* GC_LONG_REFS_NOT_NEEDED */
1104 "%lu finalization table entries; "
1105 "%lu disappearing links alive\n",
1106 (unsigned long)GC_fo_entries,
1107 (unsigned long)GC_dl_hashtbl.entries);
1108 for (; 0 != fo; fo = fo_next(fo)) ++ready;
1109 GC_log_printf("%lu objects are ready for finalization; "
1110 "%ld links cleared\n",
1112 (long)GC_old_dl_entries - (long)GC_dl_hashtbl.entries);
1113 # endif /* !GC_LONG_REFS_NOT_NEEDED */
1115 #endif /* !SMALL_CONFIG */
1117 #endif /* !GC_NO_FINALIZATION */