1 /*
2 * Copyright 1988, 1989 Hans-J. Boehm, Alan J. Demers
3 * Copyright (c) 1991-1996 by Xerox Corporation. All rights reserved.
4 * Copyright (c) 1998 by Silicon Graphics. All rights reserved.
5 * Copyright (c) 1999 by Hewlett-Packard Company. All rights reserved.
6 *
7 * THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED
8 * OR IMPLIED. ANY USE IS AT YOUR OWN RISK.
9 *
10 * Permission is hereby granted to use or copy this program
11 * for any purpose, provided the above notices are retained on all copies.
12 * Permission to modify the code and to distribute modified code is granted,
13 * provided the above notices are retained, and a notice that the code was
14 * modified is included with the above copyright notice.
15 *
16 */
17
18
19 # include "private/gc_priv.h"
20
21 # include <stdio.h>
22 # if !defined(MACOS) && !defined(MSWINCE)
23 # include <signal.h>
24 # include <sys/types.h>
25 # endif
26
27 /*
28 * Separate free lists are maintained for different sized objects
29 * up to MAXOBJSZ.
30 * The call GC_allocobj(i,k) ensures that the freelist for
31 * kind k objects of size i points to a non-empty
32 * free list. It returns a pointer to the first entry on the free list.
33 * In a single-threaded world, GC_allocobj may be called to allocate
34 * an object of (small) size i as follows:
35 *
36 * opp = &(GC_objfreelist[i]);
37 * if (*opp == 0) GC_allocobj(i, NORMAL);
38 * ptr = *opp;
39 * *opp = obj_link(ptr);
40 *
41 * Note that this is very fast if the free list is non-empty; it should
42 * only involve the execution of 4 or 5 simple instructions.
43 * All composite objects on freelists are cleared, except for
44 * their first word.
45 */
46
47 /*
48 * The allocator uses GC_allochblk to allocate large chunks of objects.
49 * These chunks all start on addresses which are multiples of
50 * HBLKSZ. Each allocated chunk has an associated header,
51 * which can be located quickly based on the address of the chunk.
52 * (See headers.c for details.)
53 * This makes it possible to check quickly whether an
54 * arbitrary address corresponds to an object administered by the
55 * allocator.
56 */
57
58 word GC_non_gc_bytes = 0; /* Number of bytes not intended to be collected */
59
60 word GC_gc_no = 0;
61
62 #ifndef SMALL_CONFIG
63 int GC_incremental = 0; /* By default, stop the world. */
64 #endif
65
66 int GC_parallel = FALSE; /* By default, parallel GC is off. */
67
68 int GC_full_freq = 19; /* Every 20th collection is a full */
69 /* collection, whether we need it */
70 /* or not. */
71
72 GC_bool GC_need_full_gc = FALSE;
73 /* Need full GC do to heap growth. */
74
75 #ifdef THREADS
76 GC_bool GC_world_stopped = FALSE;
77 # define IF_THREADS(x) x
78 #else
79 # define IF_THREADS(x)
80 #endif
81
82 word GC_used_heap_size_after_full = 0;
83
84 char * GC_copyright[] =
85 {"Copyright 1988,1989 Hans-J. Boehm and Alan J. Demers ",
86 "Copyright (c) 1991-1995 by Xerox Corporation. All rights reserved. ",
87 "Copyright (c) 1996-1998 by Silicon Graphics. All rights reserved. ",
88 "Copyright (c) 1999-2001 by Hewlett-Packard Company. All rights reserved. ",
89 "THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY",
90 " EXPRESSED OR IMPLIED. ANY USE IS AT YOUR OWN RISK.",
91 "See source code for details." };
92
93 # include "version.h"
94
95 #if defined(SAVE_CALL_CHAIN) && \
96 !(defined(REDIRECT_MALLOC) && defined(GC_HAVE_BUILTIN_BACKTRACE))
97 # define SAVE_CALL_CHAIN_IN_GC
98 /* This is only safe if the call chain save mechanism won't end up */
99 /* calling GC_malloc. The GNU C library documentation suggests */
100 /* that backtrace doesn't use malloc, but at least the initial */
101 /* call in some versions does seem to invoke the dynamic linker, */
102 /* which uses malloc. */
103 #endif
104
105 /* some more variables */
106
107 extern signed_word GC_mem_found; /* Number of reclaimed longwords */
108 /* after garbage collection */
109
110 GC_bool GC_dont_expand = 0;
111
112 word GC_free_space_divisor = 3;
113
114 extern GC_bool GC_collection_in_progress();
115 /* Collection is in progress, or was abandoned. */
116
GC_never_stop_func(void)117 int GC_never_stop_func GC_PROTO((void)) { return(0); }
118
119 unsigned long GC_time_limit = TIME_LIMIT;
120
121 CLOCK_TYPE GC_start_time; /* Time at which we stopped world. */
122 /* used only in GC_timeout_stop_func. */
123
124 int GC_n_attempts = 0; /* Number of attempts at finishing */
125 /* collection within GC_time_limit. */
126
127 #if defined(SMALL_CONFIG) || defined(NO_CLOCK)
128 # define GC_timeout_stop_func GC_never_stop_func
129 #else
GC_timeout_stop_func(void)130 int GC_timeout_stop_func GC_PROTO((void))
131 {
132 CLOCK_TYPE current_time;
133 static unsigned count = 0;
134 unsigned long time_diff;
135
136 if ((count++ & 3) != 0) return(0);
137 GET_TIME(current_time);
138 time_diff = MS_TIME_DIFF(current_time,GC_start_time);
139 if (time_diff >= GC_time_limit) {
140 # ifdef CONDPRINT
141 if (GC_print_stats) {
142 GC_printf0("Abandoning stopped marking after ");
143 GC_printf1("%lu msecs", (unsigned long)time_diff);
144 GC_printf1("(attempt %ld)\n", (unsigned long) GC_n_attempts);
145 }
146 # endif
147 return(1);
148 }
149 return(0);
150 }
151 #endif /* !SMALL_CONFIG */
152
153 /* Return the minimum number of words that must be allocated between */
154 /* collections to amortize the collection cost. */
min_words_allocd()155 static word min_words_allocd()
156 {
157 # ifdef THREADS
158 /* We punt, for now. */
159 register signed_word stack_size = 10000;
160 # else
161 int dummy;
162 register signed_word stack_size = (ptr_t)(&dummy) - GC_stackbottom;
163 # endif
164 word total_root_size; /* includes double stack size, */
165 /* since the stack is expensive */
166 /* to scan. */
167 word scan_size; /* Estimate of memory to be scanned */
168 /* during normal GC. */
169
170 if (stack_size < 0) stack_size = -stack_size;
171 total_root_size = 2 * stack_size + GC_root_size;
172 scan_size = BYTES_TO_WORDS(GC_heapsize - GC_large_free_bytes
173 + (GC_large_free_bytes >> 2)
174 /* use a bit more of large empty heap */
175 + total_root_size);
176 if (TRUE_INCREMENTAL) {
177 return scan_size / (2 * GC_free_space_divisor);
178 } else {
179 return scan_size / GC_free_space_divisor;
180 }
181 }
182
183 /* Return the number of words allocated, adjusted for explicit storage */
184 /* management, etc.. This number is used in deciding when to trigger */
185 /* collections. */
GC_adj_words_allocd()186 word GC_adj_words_allocd()
187 {
188 register signed_word result;
189 register signed_word expl_managed =
190 BYTES_TO_WORDS((long)GC_non_gc_bytes
191 - (long)GC_non_gc_bytes_at_gc);
192
193 /* Don't count what was explicitly freed, or newly allocated for */
194 /* explicit management. Note that deallocating an explicitly */
195 /* managed object should not alter result, assuming the client */
196 /* is playing by the rules. */
197 result = (signed_word)GC_words_allocd
198 - (signed_word)GC_mem_freed
199 + (signed_word)GC_finalizer_mem_freed - expl_managed;
200 if (result > (signed_word)GC_words_allocd) {
201 result = GC_words_allocd;
202 /* probably client bug or unfortunate scheduling */
203 }
204 result += GC_words_finalized;
205 /* We count objects enqueued for finalization as though they */
206 /* had been reallocated this round. Finalization is user */
207 /* visible progress. And if we don't count this, we have */
208 /* stability problems for programs that finalize all objects. */
209 if ((GC_words_wasted >> 3) < result)
210 result += GC_words_wasted;
211 /* This doesn't reflect useful work. But if there is lots of */
212 /* new fragmentation, the same is probably true of the heap, */
213 /* and the collection will be correspondingly cheaper. */
214 if (result < (signed_word)(GC_words_allocd >> 3)) {
215 /* Always count at least 1/8 of the allocations. We don't want */
216 /* to collect too infrequently, since that would inhibit */
217 /* coalescing of free storage blocks. */
218 /* This also makes us partially robust against client bugs. */
219 return(GC_words_allocd >> 3);
220 } else {
221 return(result);
222 }
223 }
224
225
226 /* Clear up a few frames worth of garbage left at the top of the stack. */
227 /* This is used to prevent us from accidentally treating garbade left */
228 /* on the stack by other parts of the collector as roots. This */
229 /* differs from the code in misc.c, which actually tries to keep the */
230 /* stack clear of long-lived, client-generated garbage. */
GC_clear_a_few_frames()231 void GC_clear_a_few_frames()
232 {
233 # define NWORDS 64
234 word frames[NWORDS];
235 /* Some compilers will warn that frames was set but never used. */
236 /* That's the whole idea ... */
237 register int i;
238
239 for (i = 0; i < NWORDS; i++) frames[i] = 0;
240 }
241
242 /* Heap size at which we need a collection to avoid expanding past */
243 /* limits used by blacklisting. */
244 static word GC_collect_at_heapsize = (word)(-1);
245
246 /* Have we allocated enough to amortize a collection? */
GC_should_collect()247 GC_bool GC_should_collect()
248 {
249 return(GC_adj_words_allocd() >= min_words_allocd()
250 || GC_heapsize >= GC_collect_at_heapsize);
251 }
252
253
GC_notify_full_gc()254 void GC_notify_full_gc()
255 {
256 if (GC_start_call_back != (void (*) GC_PROTO((void)))0) {
257 (*GC_start_call_back)();
258 }
259 }
260
261 GC_bool GC_is_full_gc = FALSE;
262
263 /*
264 * Initiate a garbage collection if appropriate.
265 * Choose judiciously
266 * between partial, full, and stop-world collections.
267 * Assumes lock held, signals disabled.
268 */
GC_maybe_gc()269 void GC_maybe_gc()
270 {
271 static int n_partial_gcs = 0;
272
273 if (GC_should_collect()) {
274 if (!GC_incremental) {
275 GC_gcollect_inner();
276 n_partial_gcs = 0;
277 return;
278 } else {
279 # ifdef PARALLEL_MARK
280 GC_wait_for_reclaim();
281 # endif
282 if (GC_need_full_gc || n_partial_gcs >= GC_full_freq) {
283 # ifdef CONDPRINT
284 if (GC_print_stats) {
285 GC_printf2(
286 "***>Full mark for collection %lu after %ld allocd bytes\n",
287 (unsigned long) GC_gc_no+1,
288 (long)WORDS_TO_BYTES(GC_words_allocd));
289 }
290 # endif
291 GC_promote_black_lists();
292 (void)GC_reclaim_all((GC_stop_func)0, TRUE);
293 GC_clear_marks();
294 n_partial_gcs = 0;
295 GC_notify_full_gc();
296 GC_is_full_gc = TRUE;
297 } else {
298 n_partial_gcs++;
299 }
300 }
301 /* We try to mark with the world stopped. */
302 /* If we run out of time, this turns into */
303 /* incremental marking. */
304 # ifndef NO_CLOCK
305 if (GC_time_limit != GC_TIME_UNLIMITED) { GET_TIME(GC_start_time); }
306 # endif
307 if (GC_stopped_mark(GC_time_limit == GC_TIME_UNLIMITED?
308 GC_never_stop_func : GC_timeout_stop_func)) {
309 # ifdef SAVE_CALL_CHAIN_IN_GC
310 GC_save_callers(GC_last_stack);
311 # endif
312 GC_finish_collection();
313 } else {
314 if (!GC_is_full_gc) {
315 /* Count this as the first attempt */
316 GC_n_attempts++;
317 }
318 }
319 }
320 }
321
322
323 /*
324 * Stop the world garbage collection. Assumes lock held, signals disabled.
325 * If stop_func is not GC_never_stop_func, then abort if stop_func returns TRUE.
326 * Return TRUE if we successfully completed the collection.
327 */
GC_try_to_collect_inner(stop_func)328 GC_bool GC_try_to_collect_inner(stop_func)
329 GC_stop_func stop_func;
330 {
331 # ifdef CONDPRINT
332 CLOCK_TYPE start_time, current_time;
333 # endif
334 if (GC_dont_gc) return FALSE;
335 if (GC_incremental && GC_collection_in_progress()) {
336 # ifdef CONDPRINT
337 if (GC_print_stats) {
338 GC_printf0(
339 "GC_try_to_collect_inner: finishing collection in progress\n");
340 }
341 # endif /* CONDPRINT */
342 /* Just finish collection already in progress. */
343 while(GC_collection_in_progress()) {
344 if (stop_func()) return(FALSE);
345 GC_collect_a_little_inner(1);
346 }
347 }
348 if (stop_func == GC_never_stop_func) GC_notify_full_gc();
349 # ifdef CONDPRINT
350 if (GC_print_stats) {
351 if (GC_print_stats) GET_TIME(start_time);
352 GC_printf2(
353 "Initiating full world-stop collection %lu after %ld allocd bytes\n",
354 (unsigned long) GC_gc_no+1,
355 (long)WORDS_TO_BYTES(GC_words_allocd));
356 }
357 # endif
358 GC_promote_black_lists();
359 /* Make sure all blocks have been reclaimed, so sweep routines */
360 /* don't see cleared mark bits. */
361 /* If we're guaranteed to finish, then this is unnecessary. */
362 /* In the find_leak case, we have to finish to guarantee that */
363 /* previously unmarked objects are not reported as leaks. */
364 # ifdef PARALLEL_MARK
365 GC_wait_for_reclaim();
366 # endif
367 if ((GC_find_leak || stop_func != GC_never_stop_func)
368 && !GC_reclaim_all(stop_func, FALSE)) {
369 /* Aborted. So far everything is still consistent. */
370 return(FALSE);
371 }
372 GC_invalidate_mark_state(); /* Flush mark stack. */
373 GC_clear_marks();
374 # ifdef SAVE_CALL_CHAIN_IN_GC
375 GC_save_callers(GC_last_stack);
376 # endif
377 GC_is_full_gc = TRUE;
378 if (!GC_stopped_mark(stop_func)) {
379 if (!GC_incremental) {
380 /* We're partially done and have no way to complete or use */
381 /* current work. Reestablish invariants as cheaply as */
382 /* possible. */
383 GC_invalidate_mark_state();
384 GC_unpromote_black_lists();
385 } /* else we claim the world is already still consistent. We'll */
386 /* finish incrementally. */
387 return(FALSE);
388 }
389 GC_finish_collection();
390 # if defined(CONDPRINT)
391 if (GC_print_stats) {
392 GET_TIME(current_time);
393 GC_printf1("Complete collection took %lu msecs\n",
394 MS_TIME_DIFF(current_time,start_time));
395 }
396 # endif
397 return(TRUE);
398 }
399
400
401
402 /*
403 * Perform n units of garbage collection work. A unit is intended to touch
404 * roughly GC_RATE pages. Every once in a while, we do more than that.
405 * This needa to be a fairly large number with our current incremental
406 * GC strategy, since otherwise we allocate too much during GC, and the
407 * cleanup gets expensive.
408 */
409 # define GC_RATE 10
410 # define MAX_PRIOR_ATTEMPTS 1
411 /* Maximum number of prior attempts at world stop marking */
412 /* A value of 1 means that we finish the second time, no matter */
413 /* how long it takes. Doesn't count the initial root scan */
414 /* for a full GC. */
415
416 int GC_deficit = 0; /* The number of extra calls to GC_mark_some */
417 /* that we have made. */
418
GC_collect_a_little_inner(n)419 void GC_collect_a_little_inner(n)
420 int n;
421 {
422 register int i;
423
424 if (GC_dont_gc) return;
425 if (GC_incremental && GC_collection_in_progress()) {
426 for (i = GC_deficit; i < GC_RATE*n; i++) {
427 if (GC_mark_some((ptr_t)0)) {
428 /* Need to finish a collection */
429 # ifdef SAVE_CALL_CHAIN_IN_GC
430 GC_save_callers(GC_last_stack);
431 # endif
432 # ifdef PARALLEL_MARK
433 GC_wait_for_reclaim();
434 # endif
435 if (GC_n_attempts < MAX_PRIOR_ATTEMPTS
436 && GC_time_limit != GC_TIME_UNLIMITED) {
437 GET_TIME(GC_start_time);
438 if (!GC_stopped_mark(GC_timeout_stop_func)) {
439 GC_n_attempts++;
440 break;
441 }
442 } else {
443 (void)GC_stopped_mark(GC_never_stop_func);
444 }
445 GC_finish_collection();
446 break;
447 }
448 }
449 if (GC_deficit > 0) GC_deficit -= GC_RATE*n;
450 if (GC_deficit < 0) GC_deficit = 0;
451 } else {
452 GC_maybe_gc();
453 }
454 }
455
GC_collect_a_little()456 int GC_collect_a_little GC_PROTO(())
457 {
458 int result;
459 DCL_LOCK_STATE;
460
461 DISABLE_SIGNALS();
462 LOCK();
463 GC_collect_a_little_inner(1);
464 result = (int)GC_collection_in_progress();
465 UNLOCK();
466 ENABLE_SIGNALS();
467 if (!result && GC_debugging_started) GC_print_all_smashed();
468 return(result);
469 }
470
471 /*
472 * Assumes lock is held, signals are disabled.
473 * We stop the world.
474 * If stop_func() ever returns TRUE, we may fail and return FALSE.
475 * Increment GC_gc_no if we succeed.
476 */
GC_stopped_mark(stop_func)477 GC_bool GC_stopped_mark(stop_func)
478 GC_stop_func stop_func;
479 {
480 register int i;
481 int dummy;
482 # if defined(PRINTTIMES) || defined(CONDPRINT)
483 CLOCK_TYPE start_time, current_time;
484 # endif
485
486 # ifdef PRINTTIMES
487 GET_TIME(start_time);
488 # endif
489 # if defined(CONDPRINT) && !defined(PRINTTIMES)
490 if (GC_print_stats) GET_TIME(start_time);
491 # endif
492 # if defined(REGISTER_LIBRARIES_EARLY)
493 GC_cond_register_dynamic_libraries();
494 # endif
495 STOP_WORLD();
496 IF_THREADS(GC_world_stopped = TRUE);
497 # ifdef CONDPRINT
498 if (GC_print_stats) {
499 GC_printf1("--> Marking for collection %lu ",
500 (unsigned long) GC_gc_no + 1);
501 GC_printf2("after %lu allocd bytes + %lu wasted bytes\n",
502 (unsigned long) WORDS_TO_BYTES(GC_words_allocd),
503 (unsigned long) WORDS_TO_BYTES(GC_words_wasted));
504 }
505 # endif
506 # ifdef MAKE_BACK_GRAPH
507 if (GC_print_back_height) {
508 GC_build_back_graph();
509 }
510 # endif
511
512 /* Mark from all roots. */
513 /* Minimize junk left in my registers and on the stack */
514 GC_clear_a_few_frames();
515 GC_noop(0,0,0,0,0,0);
516 GC_initiate_gc();
517 for(i = 0;;i++) {
518 if ((*stop_func)()) {
519 # ifdef CONDPRINT
520 if (GC_print_stats) {
521 GC_printf0("Abandoned stopped marking after ");
522 GC_printf1("%lu iterations\n",
523 (unsigned long)i);
524 }
525 # endif
526 GC_deficit = i; /* Give the mutator a chance. */
527 IF_THREADS(GC_world_stopped = FALSE);
528 START_WORLD();
529 return(FALSE);
530 }
531 if (GC_mark_some((ptr_t)(&dummy))) break;
532 }
533
534 GC_gc_no++;
535 # ifdef PRINTSTATS
536 GC_printf2("Collection %lu reclaimed %ld bytes",
537 (unsigned long) GC_gc_no - 1,
538 (long)WORDS_TO_BYTES(GC_mem_found));
539 # else
540 # ifdef CONDPRINT
541 if (GC_print_stats) {
542 GC_printf1("Collection %lu finished", (unsigned long) GC_gc_no - 1);
543 }
544 # endif
545 # endif /* !PRINTSTATS */
546 # ifdef CONDPRINT
547 if (GC_print_stats) {
548 GC_printf1(" ---> heapsize = %lu bytes\n",
549 (unsigned long) GC_heapsize);
550 /* Printf arguments may be pushed in funny places. Clear the */
551 /* space. */
552 GC_printf0("");
553 }
554 # endif /* CONDPRINT */
555
556 /* Check all debugged objects for consistency */
557 if (GC_debugging_started) {
558 (*GC_check_heap)();
559 }
560
561 IF_THREADS(GC_world_stopped = FALSE);
562 START_WORLD();
563 # ifdef PRINTTIMES
564 GET_TIME(current_time);
565 GC_printf1("World-stopped marking took %lu msecs\n",
566 MS_TIME_DIFF(current_time,start_time));
567 # else
568 # ifdef CONDPRINT
569 if (GC_print_stats) {
570 GET_TIME(current_time);
571 GC_printf1("World-stopped marking took %lu msecs\n",
572 MS_TIME_DIFF(current_time,start_time));
573 }
574 # endif
575 # endif
576 return(TRUE);
577 }
578
579 /* Set all mark bits for the free list whose first entry is q */
580 #ifdef __STDC__
GC_set_fl_marks(ptr_t q)581 void GC_set_fl_marks(ptr_t q)
582 #else
583 void GC_set_fl_marks(q)
584 ptr_t q;
585 #endif
586 {
587 ptr_t p;
588 struct hblk * h, * last_h = 0;
589 hdr *hhdr;
590 int word_no;
591
592 for (p = q; p != 0; p = obj_link(p)){
593 h = HBLKPTR(p);
594 if (h != last_h) {
595 last_h = h;
596 hhdr = HDR(h);
597 }
598 word_no = (((word *)p) - ((word *)h));
599 set_mark_bit_from_hdr(hhdr, word_no);
600 }
601 }
602
603 /* Clear all mark bits for the free list whose first entry is q */
604 /* Decrement GC_mem_found by number of words on free list. */
605 #ifdef __STDC__
GC_clear_fl_marks(ptr_t q)606 void GC_clear_fl_marks(ptr_t q)
607 #else
608 void GC_clear_fl_marks(q)
609 ptr_t q;
610 #endif
611 {
612 ptr_t p;
613 struct hblk * h, * last_h = 0;
614 hdr *hhdr;
615 int word_no;
616
617 for (p = q; p != 0; p = obj_link(p)){
618 h = HBLKPTR(p);
619 if (h != last_h) {
620 last_h = h;
621 hhdr = HDR(h);
622 }
623 word_no = (((word *)p) - ((word *)h));
624 clear_mark_bit_from_hdr(hhdr, word_no);
625 # ifdef GATHERSTATS
626 GC_mem_found -= hhdr -> hb_sz;
627 # endif
628 }
629 }
630
631 /* Finish up a collection. Assumes lock is held, signals are disabled, */
632 /* but the world is otherwise running. */
GC_finish_collection()633 void GC_finish_collection()
634 {
635 # ifdef PRINTTIMES
636 CLOCK_TYPE start_time;
637 CLOCK_TYPE finalize_time;
638 CLOCK_TYPE done_time;
639
640 GET_TIME(start_time);
641 finalize_time = start_time;
642 # endif
643
644 # ifdef GATHERSTATS
645 GC_mem_found = 0;
646 # endif
647 # if defined(LINUX) && defined(__ELF__) && !defined(SMALL_CONFIG)
648 if (getenv("GC_PRINT_ADDRESS_MAP") != 0) {
649 GC_print_address_map();
650 }
651 # endif
652 COND_DUMP;
653 if (GC_find_leak) {
654 /* Mark all objects on the free list. All objects should be */
655 /* marked when we're done. */
656 {
657 register word size; /* current object size */
658 int kind;
659 ptr_t q;
660
661 for (kind = 0; kind < GC_n_kinds; kind++) {
662 for (size = 1; size <= MAXOBJSZ; size++) {
663 q = GC_obj_kinds[kind].ok_freelist[size];
664 if (q != 0) GC_set_fl_marks(q);
665 }
666 }
667 }
668 GC_start_reclaim(TRUE);
669 /* The above just checks; it doesn't really reclaim anything. */
670 }
671
672 GC_finalize();
673 # ifdef STUBBORN_ALLOC
674 GC_clean_changing_list();
675 # endif
676
677 # ifdef PRINTTIMES
678 GET_TIME(finalize_time);
679 # endif
680
681 if (GC_print_back_height) {
682 # ifdef MAKE_BACK_GRAPH
683 GC_traverse_back_graph();
684 # else
685 # ifndef SMALL_CONFIG
686 GC_err_printf0("Back height not available: "
687 "Rebuild collector with -DMAKE_BACK_GRAPH\n");
688 # endif
689 # endif
690 }
691
692 /* Clear free list mark bits, in case they got accidentally marked */
693 /* (or GC_find_leak is set and they were intentionally marked). */
694 /* Also subtract memory remaining from GC_mem_found count. */
695 /* Note that composite objects on free list are cleared. */
696 /* Thus accidentally marking a free list is not a problem; only */
697 /* objects on the list itself will be marked, and that's fixed here. */
698 {
699 register word size; /* current object size */
700 register ptr_t q; /* pointer to current object */
701 int kind;
702
703 for (kind = 0; kind < GC_n_kinds; kind++) {
704 for (size = 1; size <= MAXOBJSZ; size++) {
705 q = GC_obj_kinds[kind].ok_freelist[size];
706 if (q != 0) GC_clear_fl_marks(q);
707 }
708 }
709 }
710
711
712 # ifdef PRINTSTATS
713 GC_printf1("Bytes recovered before sweep - f.l. count = %ld\n",
714 (long)WORDS_TO_BYTES(GC_mem_found));
715 # endif
716 /* Reconstruct free lists to contain everything not marked */
717 GC_start_reclaim(FALSE);
718 if (GC_is_full_gc) {
719 GC_used_heap_size_after_full = USED_HEAP_SIZE;
720 GC_need_full_gc = FALSE;
721 } else {
722 GC_need_full_gc =
723 BYTES_TO_WORDS(USED_HEAP_SIZE - GC_used_heap_size_after_full)
724 > min_words_allocd();
725 }
726
727 # ifdef PRINTSTATS
728 GC_printf2(
729 "Immediately reclaimed %ld bytes in heap of size %lu bytes",
730 (long)WORDS_TO_BYTES(GC_mem_found),
731 (unsigned long)GC_heapsize);
732 # ifdef USE_MUNMAP
733 GC_printf1("(%lu unmapped)", GC_unmapped_bytes);
734 # endif
735 GC_printf2(
736 "\n%lu (atomic) + %lu (composite) collectable bytes in use\n",
737 (unsigned long)WORDS_TO_BYTES(GC_atomic_in_use),
738 (unsigned long)WORDS_TO_BYTES(GC_composite_in_use));
739 # endif
740
741 GC_n_attempts = 0;
742 GC_is_full_gc = FALSE;
743 /* Reset or increment counters for next cycle */
744 GC_words_allocd_before_gc += GC_words_allocd;
745 GC_non_gc_bytes_at_gc = GC_non_gc_bytes;
746 GC_words_allocd = 0;
747 GC_words_wasted = 0;
748 GC_mem_freed = 0;
749 GC_finalizer_mem_freed = 0;
750
751 # ifdef USE_MUNMAP
752 GC_unmap_old();
753 # endif
754 # ifdef PRINTTIMES
755 GET_TIME(done_time);
756 GC_printf2("Finalize + initiate sweep took %lu + %lu msecs\n",
757 MS_TIME_DIFF(finalize_time,start_time),
758 MS_TIME_DIFF(done_time,finalize_time));
759 # endif
760 }
761
762 /* Externally callable routine to invoke full, stop-world collection */
763 # if defined(__STDC__) || defined(__cplusplus)
GC_try_to_collect(GC_stop_func stop_func)764 int GC_try_to_collect(GC_stop_func stop_func)
765 # else
766 int GC_try_to_collect(stop_func)
767 GC_stop_func stop_func;
768 # endif
769 {
770 int result;
771 DCL_LOCK_STATE;
772
773 if (GC_debugging_started) GC_print_all_smashed();
774 GC_INVOKE_FINALIZERS();
775 DISABLE_SIGNALS();
776 LOCK();
777 ENTER_GC();
778 if (!GC_is_initialized) GC_init_inner();
779 /* Minimize junk left in my registers */
780 GC_noop(0,0,0,0,0,0);
781 result = (int)GC_try_to_collect_inner(stop_func);
782 EXIT_GC();
783 UNLOCK();
784 ENABLE_SIGNALS();
785 if(result) {
786 if (GC_debugging_started) GC_print_all_smashed();
787 GC_INVOKE_FINALIZERS();
788 }
789 return(result);
790 }
791
GC_gcollect()792 void GC_gcollect GC_PROTO(())
793 {
794 (void)GC_try_to_collect(GC_never_stop_func);
795 if (GC_have_errors) GC_print_all_errors();
796 }
797
798 word GC_n_heap_sects = 0; /* Number of sections currently in heap. */
799
800 /*
801 * Use the chunk of memory starting at p of size bytes as part of the heap.
802 * Assumes p is HBLKSIZE aligned, and bytes is a multiple of HBLKSIZE.
803 */
GC_add_to_heap(p,bytes)804 void GC_add_to_heap(p, bytes)
805 struct hblk *p;
806 word bytes;
807 {
808 word words;
809 hdr * phdr;
810
811 if (GC_n_heap_sects >= MAX_HEAP_SECTS) {
812 ABORT("Too many heap sections: Increase MAXHINCR or MAX_HEAP_SECTS");
813 }
814 phdr = GC_install_header(p);
815 if (0 == phdr) {
816 /* This is extremely unlikely. Can't add it. This will */
817 /* almost certainly result in a 0 return from the allocator, */
818 /* which is entirely appropriate. */
819 return;
820 }
821 GC_heap_sects[GC_n_heap_sects].hs_start = (ptr_t)p;
822 GC_heap_sects[GC_n_heap_sects].hs_bytes = bytes;
823 GC_n_heap_sects++;
824 words = BYTES_TO_WORDS(bytes);
825 phdr -> hb_sz = words;
826 phdr -> hb_map = (unsigned char *)1; /* A value != GC_invalid_map */
827 phdr -> hb_flags = 0;
828 GC_freehblk(p);
829 GC_heapsize += bytes;
830 if ((ptr_t)p <= (ptr_t)GC_least_plausible_heap_addr
831 || GC_least_plausible_heap_addr == 0) {
832 GC_least_plausible_heap_addr = (GC_PTR)((ptr_t)p - sizeof(word));
833 /* Making it a little smaller than necessary prevents */
834 /* us from getting a false hit from the variable */
835 /* itself. There's some unintentional reflection */
836 /* here. */
837 }
838 if ((ptr_t)p + bytes >= (ptr_t)GC_greatest_plausible_heap_addr) {
839 GC_greatest_plausible_heap_addr = (GC_PTR)((ptr_t)p + bytes);
840 }
841 }
842
843 # if !defined(NO_DEBUGGING)
GC_print_heap_sects()844 void GC_print_heap_sects()
845 {
846 register unsigned i;
847
848 GC_printf1("Total heap size: %lu\n", (unsigned long) GC_heapsize);
849 for (i = 0; i < GC_n_heap_sects; i++) {
850 unsigned long start = (unsigned long) GC_heap_sects[i].hs_start;
851 unsigned long len = (unsigned long) GC_heap_sects[i].hs_bytes;
852 struct hblk *h;
853 unsigned nbl = 0;
854
855 GC_printf3("Section %ld from 0x%lx to 0x%lx ", (unsigned long)i,
856 start, (unsigned long)(start + len));
857 for (h = (struct hblk *)start; h < (struct hblk *)(start + len); h++) {
858 if (GC_is_black_listed(h, HBLKSIZE)) nbl++;
859 }
860 GC_printf2("%lu/%lu blacklisted\n", (unsigned long)nbl,
861 (unsigned long)(len/HBLKSIZE));
862 }
863 }
864 # endif
865
866 GC_PTR GC_least_plausible_heap_addr = (GC_PTR)ONES;
867 GC_PTR GC_greatest_plausible_heap_addr = 0;
868
GC_max(x,y)869 ptr_t GC_max(x,y)
870 ptr_t x, y;
871 {
872 return(x > y? x : y);
873 }
874
GC_min(x,y)875 ptr_t GC_min(x,y)
876 ptr_t x, y;
877 {
878 return(x < y? x : y);
879 }
880
881 # if defined(__STDC__) || defined(__cplusplus)
GC_set_max_heap_size(GC_word n)882 void GC_set_max_heap_size(GC_word n)
883 # else
884 void GC_set_max_heap_size(n)
885 GC_word n;
886 # endif
887 {
888 GC_max_heapsize = n;
889 }
890
891 GC_word GC_max_retries = 0;
892
893 /*
894 * this explicitly increases the size of the heap. It is used
895 * internally, but may also be invoked from GC_expand_hp by the user.
896 * The argument is in units of HBLKSIZE.
897 * Tiny values of n are rounded up.
898 * Returns FALSE on failure.
899 */
GC_expand_hp_inner(n)900 GC_bool GC_expand_hp_inner(n)
901 word n;
902 {
903 word bytes;
904 struct hblk * space;
905 word expansion_slop; /* Number of bytes by which we expect the */
906 /* heap to expand soon. */
907
908 if (n < MINHINCR) n = MINHINCR;
909 bytes = n * HBLKSIZE;
910 /* Make sure bytes is a multiple of GC_page_size */
911 {
912 word mask = GC_page_size - 1;
913 bytes += mask;
914 bytes &= ~mask;
915 }
916
917 if (GC_max_heapsize != 0 && GC_heapsize + bytes > GC_max_heapsize) {
918 /* Exceeded self-imposed limit */
919 return(FALSE);
920 }
921 space = GET_MEM(bytes);
922 if( space == 0 ) {
923 # ifdef CONDPRINT
924 if (GC_print_stats) {
925 GC_printf1("Failed to expand heap by %ld bytes\n",
926 (unsigned long)bytes);
927 }
928 # endif
929 return(FALSE);
930 }
931 # ifdef CONDPRINT
932 if (GC_print_stats) {
933 GC_printf2("Increasing heap size by %lu after %lu allocated bytes\n",
934 (unsigned long)bytes,
935 (unsigned long)WORDS_TO_BYTES(GC_words_allocd));
936 # ifdef UNDEFINED
937 GC_printf1("Root size = %lu\n", GC_root_size);
938 GC_print_block_list(); GC_print_hblkfreelist();
939 GC_printf0("\n");
940 # endif
941 }
942 # endif
943 expansion_slop = WORDS_TO_BYTES(min_words_allocd()) + 4*MAXHINCR*HBLKSIZE;
944 if (GC_last_heap_addr == 0 && !((word)space & SIGNB)
945 || (GC_last_heap_addr != 0 && GC_last_heap_addr < (ptr_t)space)) {
946 /* Assume the heap is growing up */
947 GC_greatest_plausible_heap_addr =
948 (GC_PTR)GC_max((ptr_t)GC_greatest_plausible_heap_addr,
949 (ptr_t)space + bytes + expansion_slop);
950 } else {
951 /* Heap is growing down */
952 GC_least_plausible_heap_addr =
953 (GC_PTR)GC_min((ptr_t)GC_least_plausible_heap_addr,
954 (ptr_t)space - expansion_slop);
955 }
956 # if defined(LARGE_CONFIG)
957 if (((ptr_t)GC_greatest_plausible_heap_addr <= (ptr_t)space + bytes
958 || (ptr_t)GC_least_plausible_heap_addr >= (ptr_t)space)
959 && GC_heapsize > 0) {
960 /* GC_add_to_heap will fix this, but ... */
961 WARN("Too close to address space limit: blacklisting ineffective\n", 0);
962 }
963 # endif
964 GC_prev_heap_addr = GC_last_heap_addr;
965 GC_last_heap_addr = (ptr_t)space;
966 GC_add_to_heap(space, bytes);
967 /* Force GC before we are likely to allocate past expansion_slop */
968 GC_collect_at_heapsize =
969 GC_heapsize + expansion_slop - 2*MAXHINCR*HBLKSIZE;
970 # if defined(LARGE_CONFIG)
971 if (GC_collect_at_heapsize < GC_heapsize /* wrapped */)
972 GC_collect_at_heapsize = (word)(-1);
973 # endif
974 return(TRUE);
975 }
976
977 /* Really returns a bool, but it's externally visible, so that's clumsy. */
978 /* Arguments is in bytes. */
979 # if defined(__STDC__) || defined(__cplusplus)
GC_expand_hp(size_t bytes)980 int GC_expand_hp(size_t bytes)
981 # else
982 int GC_expand_hp(bytes)
983 size_t bytes;
984 # endif
985 {
986 int result;
987 DCL_LOCK_STATE;
988
989 DISABLE_SIGNALS();
990 LOCK();
991 if (!GC_is_initialized) GC_init_inner();
992 result = (int)GC_expand_hp_inner(divHBLKSZ((word)bytes));
993 if (result) GC_requested_heapsize += bytes;
994 UNLOCK();
995 ENABLE_SIGNALS();
996 return(result);
997 }
998
999 unsigned GC_fail_count = 0;
1000 /* How many consecutive GC/expansion failures? */
1001 /* Reset by GC_allochblk. */
1002
GC_collect_or_expand(needed_blocks,ignore_off_page)1003 GC_bool GC_collect_or_expand(needed_blocks, ignore_off_page)
1004 word needed_blocks;
1005 GC_bool ignore_off_page;
1006 {
1007 if (!GC_incremental && !GC_dont_gc &&
1008 ((GC_dont_expand && GC_words_allocd > 0) || GC_should_collect())) {
1009 GC_gcollect_inner();
1010 } else {
1011 word blocks_to_get = GC_heapsize/(HBLKSIZE*GC_free_space_divisor)
1012 + needed_blocks;
1013
1014 if (blocks_to_get > MAXHINCR) {
1015 word slop;
1016
1017 /* Get the minimum required to make it likely that we */
1018 /* can satisfy the current request in the presence of black- */
1019 /* listing. This will probably be more than MAXHINCR. */
1020 if (ignore_off_page) {
1021 slop = 4;
1022 } else {
1023 slop = 2*divHBLKSZ(BL_LIMIT);
1024 if (slop > needed_blocks) slop = needed_blocks;
1025 }
1026 if (needed_blocks + slop > MAXHINCR) {
1027 blocks_to_get = needed_blocks + slop;
1028 } else {
1029 blocks_to_get = MAXHINCR;
1030 }
1031 }
1032 if (!GC_expand_hp_inner(blocks_to_get)
1033 && !GC_expand_hp_inner(needed_blocks)) {
1034 if (GC_fail_count++ < GC_max_retries) {
1035 WARN("Out of Memory! Trying to continue ...\n", 0);
1036 GC_gcollect_inner();
1037 } else {
1038 # if !defined(AMIGA) || !defined(GC_AMIGA_FASTALLOC)
1039 WARN("Out of Memory! Returning NIL!\n", 0);
1040 # endif
1041 return(FALSE);
1042 }
1043 } else {
1044 # ifdef CONDPRINT
1045 if (GC_fail_count && GC_print_stats) {
1046 GC_printf0("Memory available again ...\n");
1047 }
1048 # endif
1049 }
1050 }
1051 return(TRUE);
1052 }
1053
1054 /*
1055 * Make sure the object free list for sz is not empty.
1056 * Return a pointer to the first object on the free list.
1057 * The object MUST BE REMOVED FROM THE FREE LIST BY THE CALLER.
1058 * Assumes we hold the allocator lock and signals are disabled.
1059 *
1060 */
GC_allocobj(sz,kind)1061 ptr_t GC_allocobj(sz, kind)
1062 word sz;
1063 int kind;
1064 {
1065 ptr_t * flh = &(GC_obj_kinds[kind].ok_freelist[sz]);
1066 GC_bool tried_minor = FALSE;
1067
1068 if (sz == 0) return(0);
1069
1070 while (*flh == 0) {
1071 ENTER_GC();
1072 /* Do our share of marking work */
1073 if(TRUE_INCREMENTAL) GC_collect_a_little_inner(1);
1074 /* Sweep blocks for objects of this size */
1075 GC_continue_reclaim(sz, kind);
1076 EXIT_GC();
1077 if (*flh == 0) {
1078 GC_new_hblk(sz, kind);
1079 }
1080 if (*flh == 0) {
1081 ENTER_GC();
1082 if (GC_incremental && GC_time_limit == GC_TIME_UNLIMITED
1083 && ! tried_minor ) {
1084 GC_collect_a_little_inner(1);
1085 tried_minor = TRUE;
1086 } else {
1087 if (!GC_collect_or_expand((word)1,FALSE)) {
1088 EXIT_GC();
1089 return(0);
1090 }
1091 }
1092 EXIT_GC();
1093 }
1094 }
1095 /* Successful allocation; reset failure count. */
1096 GC_fail_count = 0;
1097
1098 return(*flh);
1099 }
1100