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 GC_ll_hashtbl = { /* head */ NULL, /* log_size */ -1, /* entries */ 0};
54 STATIC struct finalizable_object {
55 struct hash_chain_entry prolog;
56 # define fo_hidden_base prolog.hidden_key
57 /* Pointer to object base. */
58 /* No longer hidden once object */
59 /* is on finalize_now queue. */
60 # define fo_next(x) (struct finalizable_object *)((x) -> prolog.next)
61 # define fo_set_next(x,y) ((x)->prolog.next = (struct hash_chain_entry *)(y))
62 GC_finalization_proc fo_fn; /* Finalizer. */
64 word fo_object_size; /* In bytes. */
65 finalization_mark_proc fo_mark_proc; /* Mark-through procedure */
68 STATIC struct finalizable_object * GC_finalize_now = 0;
69 /* List of objects that should be finalized now. */
71 static signed_word log_fo_table_size = -1;
73 GC_INNER void GC_push_finalizer_structures(void)
75 GC_ASSERT((word)&GC_dl_hashtbl.head % sizeof(word) == 0);
76 GC_ASSERT((word)&GC_ll_hashtbl.head % sizeof(word) == 0);
77 GC_ASSERT((word)&GC_fo_head % sizeof(word) == 0);
78 GC_ASSERT((word)&GC_finalize_now % sizeof(word) == 0);
80 GC_push_all((ptr_t)(&GC_dl_hashtbl.head),
81 (ptr_t)(&GC_dl_hashtbl.head) + sizeof(word));
82 GC_push_all((ptr_t)(&GC_ll_hashtbl.head),
83 (ptr_t)(&GC_ll_hashtbl.head) + sizeof(word));
84 GC_push_all((ptr_t)(&GC_fo_head), (ptr_t)(&GC_fo_head) + sizeof(word));
85 GC_push_all((ptr_t)(&GC_finalize_now),
86 (ptr_t)(&GC_finalize_now) + sizeof(word));
89 /* Double the size of a hash table. *size_ptr is the log of its current */
90 /* size. May be a no-op. */
91 /* *table is a pointer to an array of hash headers. If we succeed, we */
92 /* update both *table and *log_size_ptr. */
94 STATIC void GC_grow_table(struct hash_chain_entry ***table,
95 signed_word *log_size_ptr)
98 register struct hash_chain_entry *p;
99 signed_word log_old_size = *log_size_ptr;
100 signed_word log_new_size = log_old_size + 1;
101 word old_size = ((log_old_size == -1)? 0: (1 << log_old_size));
102 word new_size = (word)1 << log_new_size;
103 /* FIXME: Power of 2 size often gets rounded up to one more page. */
104 struct hash_chain_entry **new_table = (struct hash_chain_entry **)
105 GC_INTERNAL_MALLOC_IGNORE_OFF_PAGE(
106 (size_t)new_size * sizeof(struct hash_chain_entry *), NORMAL);
108 if (new_table == 0) {
110 ABORT("Insufficient space for initial table allocation");
115 for (i = 0; i < old_size; i++) {
118 ptr_t real_key = GC_REVEAL_POINTER(p -> hidden_key);
119 struct hash_chain_entry *next = p -> next;
120 size_t new_hash = HASH3(real_key, new_size, log_new_size);
122 p -> next = new_table[new_hash];
123 new_table[new_hash] = p;
127 *log_size_ptr = log_new_size;
131 GC_API int GC_CALL GC_register_disappearing_link(void * * link)
135 base = (ptr_t)GC_base(link);
137 ABORT("Bad arg to GC_register_disappearing_link");
138 return(GC_general_register_disappearing_link(link, base));
141 GC_INLINE int GC_register_disappearing_link_inner(
142 struct dl_hashtbl_s *dl_hashtbl, void **link,
145 struct disappearing_link *curr_dl;
147 struct disappearing_link * new_dl;
151 GC_ASSERT(obj != NULL && GC_base_C(obj) == obj);
152 if (dl_hashtbl -> log_size == -1
153 || dl_hashtbl -> entries > ((word)1 << dl_hashtbl -> log_size)) {
154 GC_grow_table((struct hash_chain_entry ***)&dl_hashtbl -> head,
155 &dl_hashtbl -> log_size);
156 GC_COND_LOG_PRINTF("Grew dl table to %u entries\n",
157 1 << (unsigned)dl_hashtbl -> log_size);
159 index = HASH2(link, dl_hashtbl -> log_size);
160 for (curr_dl = dl_hashtbl -> head[index]; curr_dl != 0;
161 curr_dl = dl_next(curr_dl)) {
162 if (curr_dl -> dl_hidden_link == GC_HIDE_POINTER(link)) {
163 curr_dl -> dl_hidden_obj = GC_HIDE_POINTER(obj);
168 new_dl = (struct disappearing_link *)
169 GC_INTERNAL_MALLOC(sizeof(struct disappearing_link),NORMAL);
171 GC_oom_func oom_fn = GC_oom_fn;
173 new_dl = (struct disappearing_link *)
174 (*oom_fn)(sizeof(struct disappearing_link));
178 /* It's not likely we'll make it here, but ... */
180 /* Recalculate index since the table may grow. */
181 index = HASH2(link, dl_hashtbl -> log_size);
182 /* Check again that our disappearing link not in the table. */
183 for (curr_dl = dl_hashtbl -> head[index]; curr_dl != 0;
184 curr_dl = dl_next(curr_dl)) {
185 if (curr_dl -> dl_hidden_link == GC_HIDE_POINTER(link)) {
186 curr_dl -> dl_hidden_obj = GC_HIDE_POINTER(obj);
188 # ifndef DBG_HDRS_ALL
189 /* Free unused new_dl returned by GC_oom_fn() */
190 GC_free((void *)new_dl);
196 new_dl -> dl_hidden_obj = GC_HIDE_POINTER(obj);
197 new_dl -> dl_hidden_link = GC_HIDE_POINTER(link);
198 dl_set_next(new_dl, dl_hashtbl -> head[index]);
199 dl_hashtbl -> head[index] = new_dl;
200 dl_hashtbl -> entries++;
205 GC_API int GC_CALL GC_general_register_disappearing_link(void * * link,
208 if (((word)link & (ALIGNMENT-1)) != 0 || NULL == link)
209 ABORT("Bad arg to GC_general_register_disappearing_link");
210 return GC_register_disappearing_link_inner(&GC_dl_hashtbl, link, obj);
213 GC_API int GC_CALL GC_register_long_link(void * * link, const void * obj)
215 if (((word)link & (ALIGNMENT-1)) != 0 || NULL == link)
216 ABORT("Bad arg to GC_register_long_link");
217 return GC_register_disappearing_link_inner(&GC_ll_hashtbl, link, obj);
221 # define FREE_DL_ENTRY(curr_dl) dl_set_next(curr_dl, NULL)
223 # define FREE_DL_ENTRY(curr_dl) GC_free(curr_dl)
226 /* Unregisters given link and returns the link entry to free. */
227 /* Assume the lock is held. */
228 GC_INLINE struct disappearing_link *GC_unregister_disappearing_link_inner(
229 struct dl_hashtbl_s *dl_hashtbl, void **link)
231 struct disappearing_link *curr_dl;
232 struct disappearing_link *prev_dl = NULL;
233 size_t index = HASH2(link, dl_hashtbl->log_size);
235 for (curr_dl = dl_hashtbl -> head[index]; curr_dl;
236 curr_dl = dl_next(curr_dl)) {
237 if (curr_dl -> dl_hidden_link == GC_HIDE_POINTER(link)) {
238 /* Remove found entry from the table. */
239 if (NULL == prev_dl) {
240 dl_hashtbl -> head[index] = dl_next(curr_dl);
242 dl_set_next(prev_dl, dl_next(curr_dl));
244 dl_hashtbl -> entries--;
252 GC_API int GC_CALL GC_unregister_disappearing_link(void * * link)
254 struct disappearing_link *curr_dl;
257 if (((word)link & (ALIGNMENT-1)) != 0) return(0); /* Nothing to do. */
260 curr_dl = GC_unregister_disappearing_link_inner(&GC_dl_hashtbl, link);
262 if (NULL == curr_dl) return 0;
263 FREE_DL_ENTRY(curr_dl);
267 GC_API int GC_CALL GC_unregister_long_link(void * * link)
269 struct disappearing_link *curr_dl;
272 if (((word)link & (ALIGNMENT-1)) != 0) return(0); /* Nothing to do. */
275 curr_dl = GC_unregister_disappearing_link_inner(&GC_ll_hashtbl, link);
277 if (NULL == curr_dl) return 0;
278 FREE_DL_ENTRY(curr_dl);
282 #ifndef GC_MOVE_DISAPPEARING_LINK_NOT_NEEDED
283 /* Moves a link. Assume the lock is held. */
284 GC_INLINE int GC_move_disappearing_link_inner(
285 struct dl_hashtbl_s *dl_hashtbl,
286 void **link, void **new_link)
288 struct disappearing_link *curr_dl, *prev_dl, *new_dl;
289 size_t curr_index, new_index;
290 word curr_hidden_link;
291 word new_hidden_link;
293 /* Find current link. */
294 curr_index = HASH2(link, dl_hashtbl -> log_size);
295 curr_hidden_link = GC_HIDE_POINTER(link);
297 for (curr_dl = dl_hashtbl -> head[curr_index]; curr_dl;
298 curr_dl = dl_next(curr_dl)) {
299 if (curr_dl -> dl_hidden_link == curr_hidden_link)
304 if (NULL == curr_dl) {
308 if (link == new_link) {
309 return GC_SUCCESS; /* Nothing to do. */
312 /* link found; now check new_link not present. */
313 new_index = HASH2(new_link, dl_hashtbl -> log_size);
314 new_hidden_link = GC_HIDE_POINTER(new_link);
315 for (new_dl = dl_hashtbl -> head[new_index]; new_dl;
316 new_dl = dl_next(new_dl)) {
317 if (new_dl -> dl_hidden_link == new_hidden_link) {
318 /* Target already registered; bail. */
323 /* Remove from old, add to new, update link. */
324 if (NULL == prev_dl) {
325 dl_hashtbl -> head[curr_index] = dl_next(curr_dl);
327 dl_set_next(prev_dl, dl_next(curr_dl));
329 curr_dl -> dl_hidden_link = new_hidden_link;
330 dl_set_next(curr_dl, dl_hashtbl -> head[new_index]);
331 dl_hashtbl -> head[new_index] = curr_dl;
335 GC_API int GC_CALL GC_move_disappearing_link(void **link, void **new_link)
340 if (((word)new_link & (ALIGNMENT-1)) != 0 || new_link == NULL)
341 ABORT("Bad new_link arg to GC_move_disappearing_link");
342 if (((word)link & (ALIGNMENT-1)) != 0)
343 return GC_NOT_FOUND; /* Nothing to do. */
346 result = GC_move_disappearing_link_inner(&GC_dl_hashtbl, link, new_link);
351 GC_API int GC_CALL GC_move_long_link(void **link, void **new_link)
356 if (((word)new_link & (ALIGNMENT-1)) != 0 || new_link == NULL)
357 ABORT("Bad new_link arg to GC_move_disappearing_link");
358 if (((word)link & (ALIGNMENT-1)) != 0)
359 return GC_NOT_FOUND; /* Nothing to do. */
362 result = GC_move_disappearing_link_inner(&GC_ll_hashtbl, link, new_link);
366 #endif /* !GC_MOVE_DISAPPEARING_LINK_NOT_NEEDED */
368 /* Possible finalization_marker procedures. Note that mark stack */
369 /* overflow is handled by the caller, and is not a disaster. */
370 STATIC void GC_normal_finalize_mark_proc(ptr_t p)
374 PUSH_OBJ(p, hhdr, GC_mark_stack_top,
375 &(GC_mark_stack[GC_mark_stack_size]));
378 /* This only pays very partial attention to the mark descriptor. */
379 /* It does the right thing for normal and atomic objects, and treats */
380 /* most others as normal. */
381 STATIC void GC_ignore_self_finalize_mark_proc(ptr_t p)
384 word descr = hhdr -> hb_descr;
388 ptr_t target_limit = p + hhdr -> hb_sz - 1;
390 if ((descr & GC_DS_TAGS) == GC_DS_LENGTH) {
391 scan_limit = p + descr - sizeof(word);
393 scan_limit = target_limit + 1 - sizeof(word);
395 for (q = p; (word)q <= (word)scan_limit; q += ALIGNMENT) {
397 if (r < (word)p || r > (word)target_limit) {
398 GC_PUSH_ONE_HEAP(r, q, GC_mark_stack_top);
403 STATIC void GC_null_finalize_mark_proc(ptr_t p GC_ATTR_UNUSED) {}
405 /* Possible finalization_marker procedures. Note that mark stack */
406 /* overflow is handled by the caller, and is not a disaster. */
408 /* GC_unreachable_finalize_mark_proc is an alias for normal marking, */
409 /* but it is explicitly tested for, and triggers different */
410 /* behavior. Objects registered in this way are not finalized */
411 /* if they are reachable by other finalizable objects, even if those */
412 /* other objects specify no ordering. */
413 STATIC void GC_unreachable_finalize_mark_proc(ptr_t p)
415 GC_normal_finalize_mark_proc(p);
418 /* Register a finalization function. See gc.h for details. */
419 /* The last parameter is a procedure that determines */
420 /* marking for finalization ordering. Any objects marked */
421 /* by that procedure will be guaranteed to not have been */
422 /* finalized when this finalizer is invoked. */
423 STATIC void GC_register_finalizer_inner(void * obj,
424 GC_finalization_proc fn, void *cd,
425 GC_finalization_proc *ofn, void **ocd,
426 finalization_mark_proc mp)
429 struct finalizable_object * curr_fo, * prev_fo;
431 struct finalizable_object *new_fo = 0;
432 hdr *hhdr = NULL; /* initialized to prevent warning. */
437 if (log_fo_table_size == -1
438 || GC_fo_entries > ((word)1 << log_fo_table_size)) {
439 GC_grow_table((struct hash_chain_entry ***)&GC_fo_head,
441 GC_COND_LOG_PRINTF("Grew fo table to %u entries\n",
442 1 << (unsigned)log_fo_table_size);
444 /* in the THREADS case we hold allocation lock. */
447 index = HASH2(base, log_fo_table_size);
449 curr_fo = GC_fo_head[index];
450 while (curr_fo != 0) {
451 GC_ASSERT(GC_size(curr_fo) >= sizeof(struct finalizable_object));
452 if (curr_fo -> fo_hidden_base == GC_HIDE_POINTER(base)) {
453 /* Interruption by a signal in the middle of this */
454 /* should be safe. The client may see only *ocd */
455 /* updated, but we'll declare that to be his problem. */
456 if (ocd) *ocd = (void *) (curr_fo -> fo_client_data);
457 if (ofn) *ofn = curr_fo -> fo_fn;
458 /* Delete the structure for base. */
460 GC_fo_head[index] = fo_next(curr_fo);
462 fo_set_next(prev_fo, fo_next(curr_fo));
466 /* May not happen if we get a signal. But a high */
467 /* estimate will only make the table larger than */
469 # if !defined(THREADS) && !defined(DBG_HDRS_ALL)
470 GC_free((void *)curr_fo);
473 curr_fo -> fo_fn = fn;
474 curr_fo -> fo_client_data = (ptr_t)cd;
475 curr_fo -> fo_mark_proc = mp;
476 /* Reinsert it. We deleted it first to maintain */
477 /* consistency in the event of a signal. */
479 GC_fo_head[index] = curr_fo;
481 fo_set_next(prev_fo, curr_fo);
485 # ifndef DBG_HDRS_ALL
486 if (EXPECT(new_fo != 0, FALSE)) {
487 /* Free unused new_fo returned by GC_oom_fn() */
488 GC_free((void *)new_fo);
494 curr_fo = fo_next(curr_fo);
496 if (EXPECT(new_fo != 0, FALSE)) {
497 /* new_fo is returned by GC_oom_fn(), so fn != 0 and hhdr != 0. */
507 if (EXPECT(0 == hhdr, FALSE)) {
508 /* We won't collect it, hence finalizer wouldn't be run. */
514 new_fo = (struct finalizable_object *)
515 GC_INTERNAL_MALLOC(sizeof(struct finalizable_object),NORMAL);
516 if (EXPECT(new_fo != 0, TRUE))
520 new_fo = (struct finalizable_object *)
521 (*oom_fn)(sizeof(struct finalizable_object));
523 /* No enough memory. *ocd and *ofn remains unchanged. */
526 /* It's not likely we'll make it here, but ... */
528 /* Recalculate index since the table may grow and */
529 /* check again that our finalizer is not in the table. */
531 GC_ASSERT(GC_size(new_fo) >= sizeof(struct finalizable_object));
534 new_fo -> fo_hidden_base = GC_HIDE_POINTER(base);
535 new_fo -> fo_fn = fn;
536 new_fo -> fo_client_data = (ptr_t)cd;
537 new_fo -> fo_object_size = hhdr -> hb_sz;
538 new_fo -> fo_mark_proc = mp;
539 fo_set_next(new_fo, GC_fo_head[index]);
541 GC_fo_head[index] = new_fo;
545 GC_API void GC_CALL GC_register_finalizer(void * obj,
546 GC_finalization_proc fn, void * cd,
547 GC_finalization_proc *ofn, void ** ocd)
549 GC_register_finalizer_inner(obj, fn, cd, ofn,
550 ocd, GC_normal_finalize_mark_proc);
553 GC_API void GC_CALL GC_register_finalizer_ignore_self(void * obj,
554 GC_finalization_proc fn, void * cd,
555 GC_finalization_proc *ofn, void ** ocd)
557 GC_register_finalizer_inner(obj, fn, cd, ofn,
558 ocd, GC_ignore_self_finalize_mark_proc);
561 GC_API void GC_CALL GC_register_finalizer_no_order(void * obj,
562 GC_finalization_proc fn, void * cd,
563 GC_finalization_proc *ofn, void ** ocd)
565 GC_register_finalizer_inner(obj, fn, cd, ofn,
566 ocd, GC_null_finalize_mark_proc);
569 static GC_bool need_unreachable_finalization = FALSE;
570 /* Avoid the work if this isn't used. */
572 GC_API void GC_CALL GC_register_finalizer_unreachable(void * obj,
573 GC_finalization_proc fn, void * cd,
574 GC_finalization_proc *ofn, void ** ocd)
576 need_unreachable_finalization = TRUE;
577 GC_ASSERT(GC_java_finalization);
578 GC_register_finalizer_inner(obj, fn, cd, ofn,
579 ocd, GC_unreachable_finalize_mark_proc);
583 GC_INLINE void GC_dump_finalization_links(struct dl_hashtbl_s* dl_hashtbl)
585 struct disappearing_link * curr_dl;
586 ptr_t real_ptr, real_link;
587 size_t dl_size = dl_hashtbl -> log_size == -1 ? 0 :
588 1 << dl_hashtbl -> log_size;
591 for (i = 0; i < dl_size; i++) {
592 for (curr_dl = dl_hashtbl -> head[i]; curr_dl != 0;
593 curr_dl = dl_next(curr_dl)) {
594 real_ptr = GC_REVEAL_POINTER(curr_dl -> dl_hidden_obj);
595 real_link = GC_REVEAL_POINTER(curr_dl -> dl_hidden_link);
596 GC_printf("Object: %p, Link:%p\n", real_ptr, real_link);
601 void GC_dump_finalization(void)
603 struct finalizable_object * curr_fo;
604 size_t fo_size = log_fo_table_size == -1 ? 0 : 1 << log_fo_table_size;
608 GC_printf("Disappearing short links:\n");
609 GC_dump_finalization_links(&GC_dl_hashtbl);
610 GC_printf("Disappearing long links:\n");
611 GC_dump_finalization_links(&GC_ll_hashtbl);
612 GC_printf("Finalizers:\n");
613 for (i = 0; i < fo_size; i++) {
614 for (curr_fo = GC_fo_head[i]; curr_fo != 0;
615 curr_fo = fo_next(curr_fo)) {
616 real_ptr = GC_REVEAL_POINTER(curr_fo -> fo_hidden_base);
617 GC_printf("Finalizable object: %p\n", real_ptr);
621 #endif /* !NO_DEBUGGING */
624 /* for stats printing */
625 STATIC word GC_old_dl_entries = 0, GC_old_ll_entries = 0;
629 /* Global variables to minimize the level of recursion when a client */
630 /* finalizer allocates memory. */
631 STATIC int GC_finalizer_nested = 0;
632 /* Only the lowest byte is used, the rest is */
633 /* padding for proper global data alignment */
634 /* required for some compilers (like Watcom). */
635 STATIC unsigned GC_finalizer_skipped = 0;
637 /* Checks and updates the level of finalizers recursion. */
638 /* Returns NULL if GC_invoke_finalizers() should not be called by the */
639 /* collector (to minimize the risk of a deep finalizers recursion), */
640 /* otherwise returns a pointer to GC_finalizer_nested. */
641 STATIC unsigned char *GC_check_finalizer_nested(void)
643 unsigned nesting_level = *(unsigned char *)&GC_finalizer_nested;
645 /* We are inside another GC_invoke_finalizers(). */
646 /* Skip some implicitly-called GC_invoke_finalizers() */
647 /* depending on the nesting (recursion) level. */
648 if (++GC_finalizer_skipped < (1U << nesting_level)) return NULL;
649 GC_finalizer_skipped = 0;
651 *(char *)&GC_finalizer_nested = (char)(nesting_level + 1);
652 return (unsigned char *)&GC_finalizer_nested;
656 #define ITERATE_DL_HASHTBL_BEGIN(dl_hashtbl, curr_dl, prev_dl) \
659 size_t dl_size = dl_hashtbl->log_size == -1 ? 0 : \
660 1 << dl_hashtbl->log_size; \
661 for (i = 0; i < dl_size; i++) { \
662 curr_dl = dl_hashtbl -> head[i]; \
666 #define ITERATE_DL_HASHTBL_END(curr_dl, prev_dl) \
668 curr_dl = dl_next(curr_dl); \
673 #define DELETE_DL_HASHTBL_ENTRY(dl_hashtbl, curr_dl, prev_dl, next_dl) \
675 next_dl = dl_next(curr_dl); \
676 if (NULL == prev_dl) { \
677 dl_hashtbl -> head[i] = next_dl; \
679 dl_set_next(prev_dl, next_dl); \
681 GC_clear_mark_bit(curr_dl); \
682 dl_hashtbl -> entries--; \
687 GC_INLINE void GC_make_disappearing_links_disappear(
688 struct dl_hashtbl_s* dl_hashtbl)
690 struct disappearing_link *curr, *prev, *next;
691 ptr_t real_ptr, real_link;
693 ITERATE_DL_HASHTBL_BEGIN(dl_hashtbl, curr, prev)
694 real_ptr = GC_REVEAL_POINTER(curr -> dl_hidden_obj);
695 real_link = GC_REVEAL_POINTER(curr -> dl_hidden_link);
696 if (!GC_is_marked(real_ptr)) {
697 *(word *)real_link = 0;
698 GC_clear_mark_bit(curr);
699 DELETE_DL_HASHTBL_ENTRY(dl_hashtbl, curr, prev, next);
701 ITERATE_DL_HASHTBL_END(curr, prev)
704 GC_INLINE void GC_remove_dangling_disappearing_links(
705 struct dl_hashtbl_s* dl_hashtbl)
707 struct disappearing_link *curr, *prev, *next;
710 ITERATE_DL_HASHTBL_BEGIN(dl_hashtbl, curr, prev)
711 real_link = GC_base(GC_REVEAL_POINTER(curr -> dl_hidden_link));
712 if (NULL != real_link && !GC_is_marked(real_link)) {
713 GC_clear_mark_bit(curr);
714 DELETE_DL_HASHTBL_ENTRY(dl_hashtbl, curr, prev, next);
716 ITERATE_DL_HASHTBL_END(curr, prev)
719 /* Called with held lock (but the world is running). */
720 /* Cause disappearing links to disappear and unreachable objects to be */
721 /* enqueued for finalization. */
722 GC_INNER void GC_finalize(void)
724 struct finalizable_object * curr_fo, * prev_fo, * next_fo;
727 size_t fo_size = log_fo_table_size == -1 ? 0 : 1 << log_fo_table_size;
729 # ifndef SMALL_CONFIG
730 /* Save current GC_[dl/ll]_entries value for stats printing */
731 GC_old_dl_entries = GC_dl_hashtbl.entries;
732 GC_old_ll_entries = GC_ll_hashtbl.entries;
735 GC_make_disappearing_links_disappear(&GC_dl_hashtbl);
737 /* Mark all objects reachable via chains of 1 or more pointers */
738 /* from finalizable objects. */
739 GC_ASSERT(GC_mark_state == MS_NONE);
740 for (i = 0; i < fo_size; i++) {
741 for (curr_fo = GC_fo_head[i]; curr_fo != 0;
742 curr_fo = fo_next(curr_fo)) {
743 GC_ASSERT(GC_size(curr_fo) >= sizeof(struct finalizable_object));
744 real_ptr = GC_REVEAL_POINTER(curr_fo -> fo_hidden_base);
745 if (!GC_is_marked(real_ptr)) {
746 GC_MARKED_FOR_FINALIZATION(real_ptr);
747 GC_MARK_FO(real_ptr, curr_fo -> fo_mark_proc);
748 if (GC_is_marked(real_ptr)) {
749 WARN("Finalization cycle involving %p\n", real_ptr);
754 /* Enqueue for finalization all objects that are still */
756 GC_bytes_finalized = 0;
757 for (i = 0; i < fo_size; i++) {
758 curr_fo = GC_fo_head[i];
760 while (curr_fo != 0) {
761 real_ptr = GC_REVEAL_POINTER(curr_fo -> fo_hidden_base);
762 if (!GC_is_marked(real_ptr)) {
763 if (!GC_java_finalization) {
764 GC_set_mark_bit(real_ptr);
766 /* Delete from hash table */
767 next_fo = fo_next(curr_fo);
769 GC_fo_head[i] = next_fo;
771 fo_set_next(prev_fo, next_fo);
774 /* Add to list of objects awaiting finalization. */
775 fo_set_next(curr_fo, GC_finalize_now);
776 GC_finalize_now = curr_fo;
777 /* unhide object pointer so any future collections will */
779 curr_fo -> fo_hidden_base =
780 (word)GC_REVEAL_POINTER(curr_fo -> fo_hidden_base);
781 GC_bytes_finalized +=
782 curr_fo -> fo_object_size
783 + sizeof(struct finalizable_object);
784 GC_ASSERT(GC_is_marked(GC_base(curr_fo)));
788 curr_fo = fo_next(curr_fo);
793 if (GC_java_finalization) {
794 /* make sure we mark everything reachable from objects finalized
795 using the no_order mark_proc */
796 for (curr_fo = GC_finalize_now;
797 curr_fo != NULL; curr_fo = fo_next(curr_fo)) {
798 real_ptr = (ptr_t)curr_fo -> fo_hidden_base;
799 if (!GC_is_marked(real_ptr)) {
800 if (curr_fo -> fo_mark_proc == GC_null_finalize_mark_proc) {
801 GC_MARK_FO(real_ptr, GC_normal_finalize_mark_proc);
803 if (curr_fo -> fo_mark_proc != GC_unreachable_finalize_mark_proc) {
804 GC_set_mark_bit(real_ptr);
809 /* now revive finalize-when-unreachable objects reachable from
810 other finalizable objects */
811 if (need_unreachable_finalization) {
812 curr_fo = GC_finalize_now;
814 while (curr_fo != 0) {
815 next_fo = fo_next(curr_fo);
816 if (curr_fo -> fo_mark_proc == GC_unreachable_finalize_mark_proc) {
817 real_ptr = (ptr_t)curr_fo -> fo_hidden_base;
818 if (!GC_is_marked(real_ptr)) {
819 GC_set_mark_bit(real_ptr);
822 GC_finalize_now = next_fo;
824 fo_set_next(prev_fo, next_fo);
826 curr_fo -> fo_hidden_base =
827 GC_HIDE_POINTER(curr_fo -> fo_hidden_base);
828 GC_bytes_finalized -=
829 curr_fo->fo_object_size + sizeof(struct finalizable_object);
831 i = HASH2(real_ptr, log_fo_table_size);
832 fo_set_next (curr_fo, GC_fo_head[i]);
834 GC_fo_head[i] = curr_fo;
844 GC_make_disappearing_links_disappear(&GC_ll_hashtbl);
846 GC_remove_dangling_disappearing_links(&GC_dl_hashtbl);
847 GC_remove_dangling_disappearing_links(&GC_ll_hashtbl);
850 /* Don't prevent running finalizers if there has been an allocation */
851 /* failure recently. */
853 GC_reset_finalizer_nested();
855 GC_finalizer_nested = 0;
860 #ifndef JAVA_FINALIZATION_NOT_NEEDED
862 /* Enqueue all remaining finalizers to be run - Assumes lock is held. */
863 STATIC void GC_enqueue_all_finalizers(void)
865 struct finalizable_object * curr_fo, * prev_fo, * next_fo;
870 fo_size = log_fo_table_size == -1 ? 0 : 1 << log_fo_table_size;
871 GC_bytes_finalized = 0;
872 for (i = 0; i < fo_size; i++) {
873 curr_fo = GC_fo_head[i];
875 while (curr_fo != 0) {
876 real_ptr = GC_REVEAL_POINTER(curr_fo -> fo_hidden_base);
877 GC_MARK_FO(real_ptr, GC_normal_finalize_mark_proc);
878 GC_set_mark_bit(real_ptr);
880 /* Delete from hash table */
881 next_fo = fo_next(curr_fo);
883 GC_fo_head[i] = next_fo;
885 fo_set_next(prev_fo, next_fo);
889 /* Add to list of objects awaiting finalization. */
890 fo_set_next(curr_fo, GC_finalize_now);
891 GC_finalize_now = curr_fo;
893 /* unhide object pointer so any future collections will */
895 curr_fo -> fo_hidden_base =
896 (word)GC_REVEAL_POINTER(curr_fo -> fo_hidden_base);
897 GC_bytes_finalized +=
898 curr_fo -> fo_object_size + sizeof(struct finalizable_object);
904 /* Invoke all remaining finalizers that haven't yet been run.
905 * This is needed for strict compliance with the Java standard,
906 * which can make the runtime guarantee that all finalizers are run.
907 * Unfortunately, the Java standard implies we have to keep running
908 * finalizers until there are no more left, a potential infinite loop.
910 * Note that this is even more dangerous than the usual Java
911 * finalizers, in that objects reachable from static variables
912 * may have been finalized when these finalizers are run.
913 * Finalizers run at this point must be prepared to deal with a
914 * mostly broken world.
915 * This routine is externally callable, so is called without
916 * the allocation lock.
918 GC_API void GC_CALL GC_finalize_all(void)
923 while (GC_fo_entries > 0) {
924 GC_enqueue_all_finalizers();
926 GC_invoke_finalizers();
927 /* Running the finalizers in this thread is arguably not a good */
928 /* idea when we should be notifying another thread to run them. */
929 /* But otherwise we don't have a great way to wait for them to */
936 #endif /* !JAVA_FINALIZATION_NOT_NEEDED */
938 /* Returns true if it is worth calling GC_invoke_finalizers. (Useful if */
939 /* finalizers can only be called from some kind of `safe state' and */
940 /* getting into that safe state is expensive.) */
941 GC_API int GC_CALL GC_should_invoke_finalizers(void)
943 return GC_finalize_now != 0;
946 /* Invoke finalizers for all objects that are ready to be finalized. */
947 /* Should be called without allocation lock. */
948 GC_API int GC_CALL GC_invoke_finalizers(void)
950 struct finalizable_object * curr_fo;
952 word bytes_freed_before = 0; /* initialized to prevent warning. */
955 while (GC_finalize_now != 0) {
960 bytes_freed_before = GC_bytes_freed;
961 /* Don't do this outside, since we need the lock. */
963 curr_fo = GC_finalize_now;
965 if (curr_fo != 0) GC_finalize_now = fo_next(curr_fo);
967 if (curr_fo == 0) break;
969 GC_finalize_now = fo_next(curr_fo);
971 fo_set_next(curr_fo, 0);
972 (*(curr_fo -> fo_fn))((ptr_t)(curr_fo -> fo_hidden_base),
973 curr_fo -> fo_client_data);
974 curr_fo -> fo_client_data = 0;
977 /* This is probably a bad idea. It throws off accounting if */
978 /* nearly all objects are finalizable. O.w. it shouldn't */
980 GC_free((void *)curr_fo);
983 /* bytes_freed_before is initialized whenever count != 0 */
984 if (count != 0 && bytes_freed_before != GC_bytes_freed) {
986 GC_finalizer_bytes_freed += (GC_bytes_freed - bytes_freed_before);
992 static GC_word last_finalizer_notification = 0;
994 GC_INNER void GC_notify_or_invoke_finalizers(void)
996 GC_finalizer_notifier_proc notifier_fn = 0;
997 # if defined(KEEP_BACK_PTRS) || defined(MAKE_BACK_GRAPH)
998 static word last_back_trace_gc_no = 1; /* Skip first one. */
1002 # if defined(THREADS) && !defined(KEEP_BACK_PTRS) \
1003 && !defined(MAKE_BACK_GRAPH)
1004 /* Quick check (while unlocked) for an empty finalization queue. */
1005 if (GC_finalize_now == 0) return;
1009 /* This is a convenient place to generate backtraces if appropriate, */
1010 /* since that code is not callable with the allocation lock. */
1011 # if defined(KEEP_BACK_PTRS) || defined(MAKE_BACK_GRAPH)
1012 if (GC_gc_no > last_back_trace_gc_no) {
1013 # ifdef KEEP_BACK_PTRS
1015 /* Stops when GC_gc_no wraps; that's OK. */
1016 last_back_trace_gc_no = (word)(-1); /* disable others. */
1017 for (i = 0; i < GC_backtraces; ++i) {
1018 /* FIXME: This tolerates concurrent heap mutation, */
1019 /* which may cause occasional mysterious results. */
1020 /* We need to release the GC lock, since GC_print_callers */
1021 /* acquires it. It probably shouldn't. */
1023 GC_generate_random_backtrace_no_gc();
1026 last_back_trace_gc_no = GC_gc_no;
1028 # ifdef MAKE_BACK_GRAPH
1029 if (GC_print_back_height) {
1031 GC_print_back_graph_stats();
1037 if (GC_finalize_now == 0) {
1042 if (!GC_finalize_on_demand) {
1043 unsigned char *pnested = GC_check_finalizer_nested();
1045 /* Skip GC_invoke_finalizers() if nested */
1046 if (pnested != NULL) {
1047 (void) GC_invoke_finalizers();
1048 *pnested = 0; /* Reset since no more finalizers. */
1050 GC_ASSERT(GC_finalize_now == 0);
1051 # endif /* Otherwise GC can run concurrently and add more */
1056 /* These variables require synchronization to avoid data races. */
1057 if (last_finalizer_notification != GC_gc_no) {
1058 last_finalizer_notification = GC_gc_no;
1059 notifier_fn = GC_finalizer_notifier;
1062 if (notifier_fn != 0)
1063 (*notifier_fn)(); /* Invoke the notifier */
1066 #ifndef SMALL_CONFIG
1067 GC_INNER void GC_print_finalization_stats(void)
1069 struct finalizable_object *fo = GC_finalize_now;
1070 unsigned long ready = 0;
1073 "%lu finalization table entries; "
1074 "%lu short/%lu long disappearing links alive\n",
1075 (unsigned long)GC_fo_entries,
1076 (unsigned long)GC_dl_hashtbl.entries,
1077 (unsigned long)GC_ll_hashtbl.entries);
1078 for (; 0 != fo; fo = fo_next(fo)) ++ready;
1079 GC_log_printf("%lu objects are ready for finalization; "
1080 "%ld short/%ld long links cleared\n",
1082 (long)GC_old_dl_entries - (long)GC_dl_hashtbl.entries,
1083 (long)GC_old_ll_entries - (long)GC_ll_hashtbl.entries);
1085 #endif /* !SMALL_CONFIG */
1087 #endif /* !GC_NO_FINALIZATION */