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 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))
43 word dl_hidden_obj; /* Pointer to object base */
47 struct disappearing_link **head;
52 STATIC struct dl_hashtbl_s GC_dl_hashtbl = {
53 /* head */ NULL, /* log_size */ -1, /* entries */ 0 };
54 #ifndef GC_LONG_REFS_NOT_NEEDED
55 STATIC struct dl_hashtbl_s GC_ll_hashtbl = { NULL, -1, 0 };
58 STATIC struct finalizable_object {
59 struct hash_chain_entry prolog;
60 # define fo_hidden_base prolog.hidden_key
61 /* Pointer to object base. */
62 /* No longer hidden once object */
63 /* is on finalize_now queue. */
64 # define fo_next(x) (struct finalizable_object *)((x) -> prolog.next)
65 # define fo_set_next(x,y) ((x)->prolog.next = (struct hash_chain_entry *)(y))
66 GC_finalization_proc fo_fn; /* Finalizer. */
68 word fo_object_size; /* In bytes. */
69 finalization_mark_proc fo_mark_proc; /* Mark-through procedure */
72 STATIC struct finalizable_object * GC_finalize_now = 0;
73 /* List of objects that should be finalized now. */
75 static signed_word log_fo_table_size = -1;
77 GC_INNER void GC_push_finalizer_structures(void)
79 GC_ASSERT((word)&GC_dl_hashtbl.head % sizeof(word) == 0);
80 GC_ASSERT((word)&GC_fo_head % sizeof(word) == 0);
81 GC_ASSERT((word)&GC_finalize_now % sizeof(word) == 0);
83 # ifndef GC_LONG_REFS_NOT_NEEDED
84 GC_ASSERT((word)&GC_ll_hashtbl.head % sizeof(word) == 0);
85 GC_push_all((ptr_t)(&GC_ll_hashtbl.head),
86 (ptr_t)(&GC_ll_hashtbl.head) + sizeof(word));
89 GC_push_all((ptr_t)(&GC_dl_hashtbl.head),
90 (ptr_t)(&GC_dl_hashtbl.head) + sizeof(word));
91 GC_push_all((ptr_t)(&GC_fo_head), (ptr_t)(&GC_fo_head) + sizeof(word));
92 GC_push_all((ptr_t)(&GC_finalize_now),
93 (ptr_t)(&GC_finalize_now) + sizeof(word));
96 /* Double the size of a hash table. *size_ptr is the log of its current */
97 /* size. May be a no-op. */
98 /* *table is a pointer to an array of hash headers. If we succeed, we */
99 /* update both *table and *log_size_ptr. Lock is held. */
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 /* Finalizer callback support. */
267 STATIC GC_await_finalize_proc GC_object_finalized_proc = 0;
269 GC_API void GC_CALL GC_set_await_finalize_proc(GC_await_finalize_proc fn)
274 GC_object_finalized_proc = fn;
278 GC_API GC_await_finalize_proc GC_CALL GC_get_await_finalize_proc(void)
280 GC_await_finalize_proc fn;
284 fn = GC_object_finalized_proc;
289 #ifndef GC_LONG_REFS_NOT_NEEDED
290 GC_API int GC_CALL GC_register_long_link(void * * link, const void * obj)
292 if (((word)link & (ALIGNMENT-1)) != 0 || NULL == link)
293 ABORT("Bad arg to GC_register_long_link");
294 return GC_register_disappearing_link_inner(&GC_ll_hashtbl, link, obj);
297 GC_API int GC_CALL GC_unregister_long_link(void * * link)
299 struct disappearing_link *curr_dl;
302 if (((word)link & (ALIGNMENT-1)) != 0) return(0); /* Nothing to do. */
305 curr_dl = GC_unregister_disappearing_link_inner(&GC_ll_hashtbl, link);
307 if (NULL == curr_dl) return 0;
308 FREE_DL_ENTRY(curr_dl);
311 #endif /* !GC_LONG_REFS_NOT_NEEDED */
313 #ifndef GC_MOVE_DISAPPEARING_LINK_NOT_NEEDED
314 /* Moves a link. Assume the lock is held. */
315 STATIC int GC_move_disappearing_link_inner(
316 struct dl_hashtbl_s *dl_hashtbl,
317 void **link, void **new_link)
319 struct disappearing_link *curr_dl, *prev_dl, *new_dl;
320 size_t curr_index, new_index;
321 word curr_hidden_link;
322 word new_hidden_link;
324 /* Find current link. */
325 curr_index = HASH2(link, dl_hashtbl -> log_size);
326 curr_hidden_link = GC_HIDE_POINTER(link);
328 for (curr_dl = dl_hashtbl -> head[curr_index]; curr_dl;
329 curr_dl = dl_next(curr_dl)) {
330 if (curr_dl -> dl_hidden_link == curr_hidden_link)
335 if (NULL == curr_dl) {
339 if (link == new_link) {
340 return GC_SUCCESS; /* Nothing to do. */
343 /* link found; now check new_link not present. */
344 new_index = HASH2(new_link, dl_hashtbl -> log_size);
345 new_hidden_link = GC_HIDE_POINTER(new_link);
346 for (new_dl = dl_hashtbl -> head[new_index]; new_dl;
347 new_dl = dl_next(new_dl)) {
348 if (new_dl -> dl_hidden_link == new_hidden_link) {
349 /* Target already registered; bail. */
354 /* Remove from old, add to new, update link. */
355 if (NULL == prev_dl) {
356 dl_hashtbl -> head[curr_index] = dl_next(curr_dl);
358 dl_set_next(prev_dl, dl_next(curr_dl));
360 curr_dl -> dl_hidden_link = new_hidden_link;
361 dl_set_next(curr_dl, dl_hashtbl -> head[new_index]);
362 dl_hashtbl -> head[new_index] = curr_dl;
366 GC_API int GC_CALL GC_move_disappearing_link(void **link, void **new_link)
371 if (((word)new_link & (ALIGNMENT-1)) != 0 || new_link == NULL)
372 ABORT("Bad new_link arg to GC_move_disappearing_link");
373 if (((word)link & (ALIGNMENT-1)) != 0)
374 return GC_NOT_FOUND; /* Nothing to do. */
377 result = GC_move_disappearing_link_inner(&GC_dl_hashtbl, link, new_link);
382 # ifndef GC_LONG_REFS_NOT_NEEDED
383 GC_API int GC_CALL GC_move_long_link(void **link, void **new_link)
388 if (((word)new_link & (ALIGNMENT-1)) != 0 || new_link == NULL)
389 ABORT("Bad new_link arg to GC_move_disappearing_link");
390 if (((word)link & (ALIGNMENT-1)) != 0)
391 return GC_NOT_FOUND; /* Nothing to do. */
394 result = GC_move_disappearing_link_inner(&GC_ll_hashtbl, link, new_link);
398 # endif /* !GC_LONG_REFS_NOT_NEEDED */
399 #endif /* !GC_MOVE_DISAPPEARING_LINK_NOT_NEEDED */
401 /* Possible finalization_marker procedures. Note that mark stack */
402 /* overflow is handled by the caller, and is not a disaster. */
403 STATIC void GC_normal_finalize_mark_proc(ptr_t p)
407 PUSH_OBJ(p, hhdr, GC_mark_stack_top,
408 &(GC_mark_stack[GC_mark_stack_size]));
411 /* This only pays very partial attention to the mark descriptor. */
412 /* It does the right thing for normal and atomic objects, and treats */
413 /* most others as normal. */
414 STATIC void GC_ignore_self_finalize_mark_proc(ptr_t p)
417 word descr = hhdr -> hb_descr;
421 ptr_t target_limit = p + hhdr -> hb_sz - 1;
423 if ((descr & GC_DS_TAGS) == GC_DS_LENGTH) {
424 scan_limit = p + descr - sizeof(word);
426 scan_limit = target_limit + 1 - sizeof(word);
428 for (q = p; (word)q <= (word)scan_limit; q += ALIGNMENT) {
430 if (r < (word)p || r > (word)target_limit) {
431 GC_PUSH_ONE_HEAP(r, q, GC_mark_stack_top);
436 STATIC void GC_null_finalize_mark_proc(ptr_t p GC_ATTR_UNUSED) {}
438 /* Possible finalization_marker procedures. Note that mark stack */
439 /* overflow is handled by the caller, and is not a disaster. */
441 /* GC_unreachable_finalize_mark_proc is an alias for normal marking, */
442 /* but it is explicitly tested for, and triggers different */
443 /* behavior. Objects registered in this way are not finalized */
444 /* if they are reachable by other finalizable objects, even if those */
445 /* other objects specify no ordering. */
446 STATIC void GC_unreachable_finalize_mark_proc(ptr_t p)
448 GC_normal_finalize_mark_proc(p);
451 /* Register a finalization function. See gc.h for details. */
452 /* The last parameter is a procedure that determines */
453 /* marking for finalization ordering. Any objects marked */
454 /* by that procedure will be guaranteed to not have been */
455 /* finalized when this finalizer is invoked. */
456 STATIC void GC_register_finalizer_inner(void * obj,
457 GC_finalization_proc fn, void *cd,
458 GC_finalization_proc *ofn, void **ocd,
459 finalization_mark_proc mp)
462 struct finalizable_object * curr_fo, * prev_fo;
464 struct finalizable_object *new_fo = 0;
465 hdr *hhdr = NULL; /* initialized to prevent warning. */
470 if (log_fo_table_size == -1
471 || GC_fo_entries > ((word)1 << log_fo_table_size)) {
472 GC_grow_table((struct hash_chain_entry ***)&GC_fo_head,
474 GC_COND_LOG_PRINTF("Grew fo table to %u entries\n",
475 1 << (unsigned)log_fo_table_size);
477 /* in the THREADS case we hold allocation lock. */
480 index = HASH2(base, log_fo_table_size);
482 curr_fo = GC_fo_head[index];
483 while (curr_fo != 0) {
484 GC_ASSERT(GC_size(curr_fo) >= sizeof(struct finalizable_object));
485 if (curr_fo -> fo_hidden_base == GC_HIDE_POINTER(base)) {
486 /* Interruption by a signal in the middle of this */
487 /* should be safe. The client may see only *ocd */
488 /* updated, but we'll declare that to be his problem. */
489 if (ocd) *ocd = (void *) (curr_fo -> fo_client_data);
490 if (ofn) *ofn = curr_fo -> fo_fn;
491 /* Delete the structure for base. */
493 GC_fo_head[index] = fo_next(curr_fo);
495 fo_set_next(prev_fo, fo_next(curr_fo));
499 /* May not happen if we get a signal. But a high */
500 /* estimate will only make the table larger than */
502 # if !defined(THREADS) && !defined(DBG_HDRS_ALL)
503 GC_free((void *)curr_fo);
506 curr_fo -> fo_fn = fn;
507 curr_fo -> fo_client_data = (ptr_t)cd;
508 curr_fo -> fo_mark_proc = mp;
509 /* Reinsert it. We deleted it first to maintain */
510 /* consistency in the event of a signal. */
512 GC_fo_head[index] = curr_fo;
514 fo_set_next(prev_fo, curr_fo);
518 # ifndef DBG_HDRS_ALL
519 if (EXPECT(new_fo != 0, FALSE)) {
520 /* Free unused new_fo returned by GC_oom_fn() */
521 GC_free((void *)new_fo);
527 curr_fo = fo_next(curr_fo);
529 if (EXPECT(new_fo != 0, FALSE)) {
530 /* new_fo is returned by GC_oom_fn(), so fn != 0 and hhdr != 0. */
540 if (EXPECT(0 == hhdr, FALSE)) {
541 /* We won't collect it, hence finalizer wouldn't be run. */
547 new_fo = (struct finalizable_object *)
548 GC_INTERNAL_MALLOC(sizeof(struct finalizable_object),NORMAL);
549 if (EXPECT(new_fo != 0, TRUE))
553 new_fo = (struct finalizable_object *)
554 (*oom_fn)(sizeof(struct finalizable_object));
556 /* No enough memory. *ocd and *ofn remains unchanged. */
559 /* It's not likely we'll make it here, but ... */
561 /* Recalculate index since the table may grow and */
562 /* check again that our finalizer is not in the table. */
564 GC_ASSERT(GC_size(new_fo) >= sizeof(struct finalizable_object));
567 new_fo -> fo_hidden_base = GC_HIDE_POINTER(base);
568 new_fo -> fo_fn = fn;
569 new_fo -> fo_client_data = (ptr_t)cd;
570 new_fo -> fo_object_size = hhdr -> hb_sz;
571 new_fo -> fo_mark_proc = mp;
572 fo_set_next(new_fo, GC_fo_head[index]);
574 GC_fo_head[index] = new_fo;
578 GC_API void GC_CALL GC_register_finalizer(void * obj,
579 GC_finalization_proc fn, void * cd,
580 GC_finalization_proc *ofn, void ** ocd)
582 GC_register_finalizer_inner(obj, fn, cd, ofn,
583 ocd, GC_normal_finalize_mark_proc);
586 GC_API void GC_CALL GC_register_finalizer_ignore_self(void * obj,
587 GC_finalization_proc fn, void * cd,
588 GC_finalization_proc *ofn, void ** ocd)
590 GC_register_finalizer_inner(obj, fn, cd, ofn,
591 ocd, GC_ignore_self_finalize_mark_proc);
594 GC_API void GC_CALL GC_register_finalizer_no_order(void * obj,
595 GC_finalization_proc fn, void * cd,
596 GC_finalization_proc *ofn, void ** ocd)
598 GC_register_finalizer_inner(obj, fn, cd, ofn,
599 ocd, GC_null_finalize_mark_proc);
602 static GC_bool need_unreachable_finalization = FALSE;
603 /* Avoid the work if this isn't used. */
605 GC_API void GC_CALL GC_register_finalizer_unreachable(void * obj,
606 GC_finalization_proc fn, void * cd,
607 GC_finalization_proc *ofn, void ** ocd)
609 need_unreachable_finalization = TRUE;
610 GC_ASSERT(GC_java_finalization);
611 GC_register_finalizer_inner(obj, fn, cd, ofn,
612 ocd, GC_unreachable_finalize_mark_proc);
616 STATIC void GC_dump_finalization_links(
617 const struct dl_hashtbl_s *dl_hashtbl)
619 struct disappearing_link *curr_dl;
620 ptr_t real_ptr, real_link;
621 size_t dl_size = dl_hashtbl->log_size == -1 ? 0 :
622 1 << dl_hashtbl->log_size;
625 for (i = 0; i < dl_size; i++) {
626 for (curr_dl = dl_hashtbl -> head[i]; curr_dl != 0;
627 curr_dl = dl_next(curr_dl)) {
628 real_ptr = GC_REVEAL_POINTER(curr_dl -> dl_hidden_obj);
629 real_link = GC_REVEAL_POINTER(curr_dl -> dl_hidden_link);
630 GC_printf("Object: %p, link: %p\n", real_ptr, real_link);
635 void GC_dump_finalization(void)
637 struct finalizable_object * curr_fo;
638 size_t fo_size = log_fo_table_size == -1 ? 0 : 1 << log_fo_table_size;
642 GC_printf("Disappearing (short) links:\n");
643 GC_dump_finalization_links(&GC_dl_hashtbl);
644 # ifndef GC_LONG_REFS_NOT_NEEDED
645 GC_printf("Disappearing long links:\n");
646 GC_dump_finalization_links(&GC_ll_hashtbl);
648 GC_printf("Finalizers:\n");
649 for (i = 0; i < fo_size; i++) {
650 for (curr_fo = GC_fo_head[i]; curr_fo != 0;
651 curr_fo = fo_next(curr_fo)) {
652 real_ptr = GC_REVEAL_POINTER(curr_fo -> fo_hidden_base);
653 GC_printf("Finalizable object: %p\n", real_ptr);
657 #endif /* !NO_DEBUGGING */
660 STATIC word GC_old_dl_entries = 0; /* for stats printing */
661 # ifndef GC_LONG_REFS_NOT_NEEDED
662 STATIC word GC_old_ll_entries = 0;
664 #endif /* !SMALL_CONFIG */
667 /* Global variables to minimize the level of recursion when a client */
668 /* finalizer allocates memory. */
669 STATIC int GC_finalizer_nested = 0;
670 /* Only the lowest byte is used, the rest is */
671 /* padding for proper global data alignment */
672 /* required for some compilers (like Watcom). */
673 STATIC unsigned GC_finalizer_skipped = 0;
675 /* Checks and updates the level of finalizers recursion. */
676 /* Returns NULL if GC_invoke_finalizers() should not be called by the */
677 /* collector (to minimize the risk of a deep finalizers recursion), */
678 /* otherwise returns a pointer to GC_finalizer_nested. */
679 STATIC unsigned char *GC_check_finalizer_nested(void)
681 unsigned nesting_level = *(unsigned char *)&GC_finalizer_nested;
683 /* We are inside another GC_invoke_finalizers(). */
684 /* Skip some implicitly-called GC_invoke_finalizers() */
685 /* depending on the nesting (recursion) level. */
686 if (++GC_finalizer_skipped < (1U << nesting_level)) return NULL;
687 GC_finalizer_skipped = 0;
689 *(char *)&GC_finalizer_nested = (char)(nesting_level + 1);
690 return (unsigned char *)&GC_finalizer_nested;
694 #define ITERATE_DL_HASHTBL_BEGIN(dl_hashtbl, curr_dl, prev_dl) \
697 size_t dl_size = dl_hashtbl->log_size == -1 ? 0 : \
698 1 << dl_hashtbl->log_size; \
699 for (i = 0; i < dl_size; i++) { \
700 curr_dl = dl_hashtbl -> head[i]; \
704 #define ITERATE_DL_HASHTBL_END(curr_dl, prev_dl) \
706 curr_dl = dl_next(curr_dl); \
711 #define DELETE_DL_HASHTBL_ENTRY(dl_hashtbl, curr_dl, prev_dl, next_dl) \
713 next_dl = dl_next(curr_dl); \
714 if (NULL == prev_dl) { \
715 dl_hashtbl -> head[i] = next_dl; \
717 dl_set_next(prev_dl, next_dl); \
719 GC_clear_mark_bit(curr_dl); \
720 dl_hashtbl -> entries--; \
725 GC_INLINE void GC_make_disappearing_links_disappear(
726 struct dl_hashtbl_s* dl_hashtbl)
728 struct disappearing_link *curr, *prev, *next;
729 ptr_t real_ptr, real_link;
731 ITERATE_DL_HASHTBL_BEGIN(dl_hashtbl, curr, prev)
732 real_ptr = GC_REVEAL_POINTER(curr -> dl_hidden_obj);
733 real_link = GC_REVEAL_POINTER(curr -> dl_hidden_link);
734 if (!GC_is_marked(real_ptr)) {
735 *(word *)real_link = 0;
736 GC_clear_mark_bit(curr);
737 DELETE_DL_HASHTBL_ENTRY(dl_hashtbl, curr, prev, next);
739 ITERATE_DL_HASHTBL_END(curr, prev)
742 GC_INLINE void GC_remove_dangling_disappearing_links(
743 struct dl_hashtbl_s* dl_hashtbl)
745 struct disappearing_link *curr, *prev, *next;
748 ITERATE_DL_HASHTBL_BEGIN(dl_hashtbl, curr, prev)
749 real_link = GC_base(GC_REVEAL_POINTER(curr -> dl_hidden_link));
750 if (NULL != real_link && !GC_is_marked(real_link)) {
751 GC_clear_mark_bit(curr);
752 DELETE_DL_HASHTBL_ENTRY(dl_hashtbl, curr, prev, next);
754 ITERATE_DL_HASHTBL_END(curr, prev)
757 /* Called with held lock (but the world is running). */
758 /* Cause disappearing links to disappear and unreachable objects to be */
759 /* enqueued for finalization. */
760 GC_INNER void GC_finalize(void)
762 struct finalizable_object * curr_fo, * prev_fo, * next_fo;
765 size_t fo_size = log_fo_table_size == -1 ? 0 : 1 << log_fo_table_size;
767 # ifndef SMALL_CONFIG
768 /* Save current GC_[dl/ll]_entries value for stats printing */
769 GC_old_dl_entries = GC_dl_hashtbl.entries;
770 # ifndef GC_LONG_REFS_NOT_NEEDED
771 GC_old_ll_entries = GC_ll_hashtbl.entries;
775 GC_make_disappearing_links_disappear(&GC_dl_hashtbl);
777 /* Mark all objects reachable via chains of 1 or more pointers */
778 /* from finalizable objects. */
779 GC_ASSERT(GC_mark_state == MS_NONE);
780 for (i = 0; i < fo_size; i++) {
781 for (curr_fo = GC_fo_head[i]; curr_fo != 0;
782 curr_fo = fo_next(curr_fo)) {
783 GC_ASSERT(GC_size(curr_fo) >= sizeof(struct finalizable_object));
784 real_ptr = GC_REVEAL_POINTER(curr_fo -> fo_hidden_base);
785 if (!GC_is_marked(real_ptr)) {
786 GC_MARKED_FOR_FINALIZATION(real_ptr);
787 GC_MARK_FO(real_ptr, curr_fo -> fo_mark_proc);
788 if (GC_is_marked(real_ptr)) {
789 WARN("Finalization cycle involving %p\n", real_ptr);
794 /* Enqueue for finalization all objects that are still */
796 GC_bytes_finalized = 0;
797 for (i = 0; i < fo_size; i++) {
798 curr_fo = GC_fo_head[i];
800 while (curr_fo != 0) {
801 real_ptr = GC_REVEAL_POINTER(curr_fo -> fo_hidden_base);
802 if (!GC_is_marked(real_ptr)) {
803 if (!GC_java_finalization) {
804 GC_set_mark_bit(real_ptr);
806 /* Delete from hash table */
807 next_fo = fo_next(curr_fo);
809 GC_fo_head[i] = next_fo;
811 fo_set_next(prev_fo, next_fo);
814 if (GC_object_finalized_proc)
815 GC_object_finalized_proc(real_ptr);
817 /* Add to list of objects awaiting finalization. */
818 fo_set_next(curr_fo, GC_finalize_now);
819 GC_finalize_now = curr_fo;
820 /* unhide object pointer so any future collections will */
822 curr_fo -> fo_hidden_base =
823 (word)GC_REVEAL_POINTER(curr_fo -> fo_hidden_base);
824 GC_bytes_finalized +=
825 curr_fo -> fo_object_size
826 + sizeof(struct finalizable_object);
827 GC_ASSERT(GC_is_marked(GC_base(curr_fo)));
831 curr_fo = fo_next(curr_fo);
836 if (GC_java_finalization) {
837 /* make sure we mark everything reachable from objects finalized
838 using the no_order mark_proc */
839 for (curr_fo = GC_finalize_now;
840 curr_fo != NULL; curr_fo = fo_next(curr_fo)) {
841 real_ptr = (ptr_t)curr_fo -> fo_hidden_base;
842 if (!GC_is_marked(real_ptr)) {
843 if (curr_fo -> fo_mark_proc == GC_null_finalize_mark_proc) {
844 GC_MARK_FO(real_ptr, GC_normal_finalize_mark_proc);
846 if (curr_fo -> fo_mark_proc != GC_unreachable_finalize_mark_proc) {
847 GC_set_mark_bit(real_ptr);
852 /* now revive finalize-when-unreachable objects reachable from
853 other finalizable objects */
854 if (need_unreachable_finalization) {
855 curr_fo = GC_finalize_now;
857 while (curr_fo != 0) {
858 next_fo = fo_next(curr_fo);
859 if (curr_fo -> fo_mark_proc == GC_unreachable_finalize_mark_proc) {
860 real_ptr = (ptr_t)curr_fo -> fo_hidden_base;
861 if (!GC_is_marked(real_ptr)) {
862 GC_set_mark_bit(real_ptr);
865 GC_finalize_now = next_fo;
867 fo_set_next(prev_fo, next_fo);
869 curr_fo -> fo_hidden_base =
870 GC_HIDE_POINTER(curr_fo -> fo_hidden_base);
871 GC_bytes_finalized -=
872 curr_fo->fo_object_size + sizeof(struct finalizable_object);
874 i = HASH2(real_ptr, log_fo_table_size);
875 fo_set_next (curr_fo, GC_fo_head[i]);
877 GC_fo_head[i] = curr_fo;
887 GC_remove_dangling_disappearing_links(&GC_dl_hashtbl);
888 # ifndef GC_LONG_REFS_NOT_NEEDED
889 GC_make_disappearing_links_disappear(&GC_ll_hashtbl);
890 GC_remove_dangling_disappearing_links(&GC_ll_hashtbl);
894 /* Don't prevent running finalizers if there has been an allocation */
895 /* failure recently. */
897 GC_reset_finalizer_nested();
899 GC_finalizer_nested = 0;
904 #ifndef JAVA_FINALIZATION_NOT_NEEDED
906 /* Enqueue all remaining finalizers to be run - Assumes lock is held. */
907 STATIC void GC_enqueue_all_finalizers(void)
909 struct finalizable_object * curr_fo, * prev_fo, * next_fo;
914 fo_size = log_fo_table_size == -1 ? 0 : 1 << log_fo_table_size;
915 GC_bytes_finalized = 0;
916 for (i = 0; i < fo_size; i++) {
917 curr_fo = GC_fo_head[i];
919 while (curr_fo != 0) {
920 real_ptr = GC_REVEAL_POINTER(curr_fo -> fo_hidden_base);
921 GC_MARK_FO(real_ptr, GC_normal_finalize_mark_proc);
922 GC_set_mark_bit(real_ptr);
924 /* Delete from hash table */
925 next_fo = fo_next(curr_fo);
927 GC_fo_head[i] = next_fo;
929 fo_set_next(prev_fo, next_fo);
933 /* Add to list of objects awaiting finalization. */
934 fo_set_next(curr_fo, GC_finalize_now);
935 GC_finalize_now = curr_fo;
937 /* unhide object pointer so any future collections will */
939 curr_fo -> fo_hidden_base =
940 (word)GC_REVEAL_POINTER(curr_fo -> fo_hidden_base);
941 GC_bytes_finalized +=
942 curr_fo -> fo_object_size + sizeof(struct finalizable_object);
948 /* Invoke all remaining finalizers that haven't yet been run.
949 * This is needed for strict compliance with the Java standard,
950 * which can make the runtime guarantee that all finalizers are run.
951 * Unfortunately, the Java standard implies we have to keep running
952 * finalizers until there are no more left, a potential infinite loop.
954 * Note that this is even more dangerous than the usual Java
955 * finalizers, in that objects reachable from static variables
956 * may have been finalized when these finalizers are run.
957 * Finalizers run at this point must be prepared to deal with a
958 * mostly broken world.
959 * This routine is externally callable, so is called without
960 * the allocation lock.
962 GC_API void GC_CALL GC_finalize_all(void)
967 while (GC_fo_entries > 0) {
968 GC_enqueue_all_finalizers();
970 GC_invoke_finalizers();
971 /* Running the finalizers in this thread is arguably not a good */
972 /* idea when we should be notifying another thread to run them. */
973 /* But otherwise we don't have a great way to wait for them to */
980 #endif /* !JAVA_FINALIZATION_NOT_NEEDED */
982 /* Returns true if it is worth calling GC_invoke_finalizers. (Useful if */
983 /* finalizers can only be called from some kind of "safe state" and */
984 /* getting into that safe state is expensive.) */
985 GC_API int GC_CALL GC_should_invoke_finalizers(void)
987 return GC_finalize_now != 0;
990 /* Invoke finalizers for all objects that are ready to be finalized. */
991 /* Should be called without allocation lock. */
992 GC_API int GC_CALL GC_invoke_finalizers(void)
994 struct finalizable_object * curr_fo;
996 word bytes_freed_before = 0; /* initialized to prevent warning. */
999 while (GC_finalize_now != 0) {
1004 bytes_freed_before = GC_bytes_freed;
1005 /* Don't do this outside, since we need the lock. */
1007 curr_fo = GC_finalize_now;
1009 if (curr_fo != 0) GC_finalize_now = fo_next(curr_fo);
1011 if (curr_fo == 0) break;
1013 GC_finalize_now = fo_next(curr_fo);
1015 fo_set_next(curr_fo, 0);
1016 (*(curr_fo -> fo_fn))((ptr_t)(curr_fo -> fo_hidden_base),
1017 curr_fo -> fo_client_data);
1018 curr_fo -> fo_client_data = 0;
1021 /* This is probably a bad idea. It throws off accounting if */
1022 /* nearly all objects are finalizable. O.w. it shouldn't */
1024 GC_free((void *)curr_fo);
1027 /* bytes_freed_before is initialized whenever count != 0 */
1028 if (count != 0 && bytes_freed_before != GC_bytes_freed) {
1030 GC_finalizer_bytes_freed += (GC_bytes_freed - bytes_freed_before);
1036 static word last_finalizer_notification = 0;
1038 GC_INNER void GC_notify_or_invoke_finalizers(void)
1040 GC_finalizer_notifier_proc notifier_fn = 0;
1041 # if defined(KEEP_BACK_PTRS) || defined(MAKE_BACK_GRAPH)
1042 static word last_back_trace_gc_no = 1; /* Skip first one. */
1046 # if defined(THREADS) && !defined(KEEP_BACK_PTRS) \
1047 && !defined(MAKE_BACK_GRAPH)
1048 /* Quick check (while unlocked) for an empty finalization queue. */
1049 if (GC_finalize_now == 0) return;
1053 /* This is a convenient place to generate backtraces if appropriate, */
1054 /* since that code is not callable with the allocation lock. */
1055 # if defined(KEEP_BACK_PTRS) || defined(MAKE_BACK_GRAPH)
1056 if (GC_gc_no > last_back_trace_gc_no) {
1057 # ifdef KEEP_BACK_PTRS
1059 /* Stops when GC_gc_no wraps; that's OK. */
1060 last_back_trace_gc_no = (word)(-1); /* disable others. */
1061 for (i = 0; i < GC_backtraces; ++i) {
1062 /* FIXME: This tolerates concurrent heap mutation, */
1063 /* which may cause occasional mysterious results. */
1064 /* We need to release the GC lock, since GC_print_callers */
1065 /* acquires it. It probably shouldn't. */
1067 GC_generate_random_backtrace_no_gc();
1070 last_back_trace_gc_no = GC_gc_no;
1072 # ifdef MAKE_BACK_GRAPH
1073 if (GC_print_back_height) {
1075 GC_print_back_graph_stats();
1081 if (GC_finalize_now == 0) {
1086 if (!GC_finalize_on_demand) {
1087 unsigned char *pnested = GC_check_finalizer_nested();
1089 /* Skip GC_invoke_finalizers() if nested */
1090 if (pnested != NULL) {
1091 (void) GC_invoke_finalizers();
1092 *pnested = 0; /* Reset since no more finalizers. */
1094 GC_ASSERT(GC_finalize_now == 0);
1095 # endif /* Otherwise GC can run concurrently and add more */
1100 /* These variables require synchronization to avoid data races. */
1101 if (last_finalizer_notification != GC_gc_no) {
1102 last_finalizer_notification = GC_gc_no;
1103 notifier_fn = GC_finalizer_notifier;
1106 if (notifier_fn != 0)
1107 (*notifier_fn)(); /* Invoke the notifier */
1110 #ifndef SMALL_CONFIG
1111 # ifndef GC_LONG_REFS_NOT_NEEDED
1112 # define IF_LONG_REFS_PRESENT_ELSE(x,y) (x)
1114 # define IF_LONG_REFS_PRESENT_ELSE(x,y) (y)
1117 GC_INNER void GC_print_finalization_stats(void)
1119 struct finalizable_object *fo;
1120 unsigned long ready = 0;
1122 GC_log_printf("%lu finalization entries;"
1123 " %lu/%lu short/long disappearing links alive\n",
1124 (unsigned long)GC_fo_entries,
1125 (unsigned long)GC_dl_hashtbl.entries,
1126 (unsigned long)IF_LONG_REFS_PRESENT_ELSE(
1127 GC_ll_hashtbl.entries, 0));
1129 for (fo = GC_finalize_now; 0 != fo; fo = fo_next(fo))
1131 GC_log_printf("%lu finalization-ready objects;"
1132 " %ld/%ld short/long links cleared\n",
1134 (long)GC_old_dl_entries - (long)GC_dl_hashtbl.entries,
1135 (long)IF_LONG_REFS_PRESENT_ELSE(
1136 GC_old_ll_entries - GC_ll_hashtbl.entries, 0));
1138 #endif /* !SMALL_CONFIG */
1140 #endif /* !GC_NO_FINALIZATION */