function.c (keep_stack_depressed): Don't use delete_insn.
[gcc.git] / gcc / ggc-common.c
1 /* Simple garbage collection for the GNU compiler.
2 Copyright (C) 1999, 2000, 2001 Free Software Foundation, Inc.
3
4 This file is part of GCC.
5
6 GCC is free software; you can redistribute it and/or modify it under
7 the terms of the GNU General Public License as published by the Free
8 Software Foundation; either version 2, or (at your option) any later
9 version.
10
11 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
12 WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 for more details.
15
16 You should have received a copy of the GNU General Public License
17 along with GCC; see the file COPYING. If not, write to the Free
18 Software Foundation, 59 Temple Place - Suite 330, Boston, MA
19 02111-1307, USA. */
20
21 /* Generic garbage collection (GC) functions and data, not specific to
22 any particular GC implementation. */
23
24 #include "config.h"
25 #include "system.h"
26 #include "rtl.h"
27 #include "tree.h"
28 #include "tm_p.h"
29 #include "hash.h"
30 #include "hashtab.h"
31 #include "varray.h"
32 #include "ggc.h"
33
34 /* Statistics about the allocation. */
35 static ggc_statistics *ggc_stats;
36
37 /* The FALSE_LABEL_STACK, declared in except.h, has language-dependent
38 semantics. If a front-end needs to mark the false label stack, it
39 should set this pointer to a non-NULL value. Otherwise, no marking
40 will be done. */
41 void (*lang_mark_false_label_stack) PARAMS ((struct label_node *));
42
43 /* Trees that have been marked, but whose children still need marking. */
44 varray_type ggc_pending_trees;
45
46 static void ggc_mark_rtx_ptr PARAMS ((void *));
47 static void ggc_mark_tree_ptr PARAMS ((void *));
48 static void ggc_mark_rtx_varray_ptr PARAMS ((void *));
49 static void ggc_mark_tree_varray_ptr PARAMS ((void *));
50 static void ggc_mark_tree_hash_table_ptr PARAMS ((void *));
51 static int ggc_htab_delete PARAMS ((void **, void *));
52 static void ggc_mark_trees PARAMS ((void));
53 static bool ggc_mark_tree_hash_table_entry PARAMS ((struct hash_entry *,
54 hash_table_key));
55
56 /* Maintain global roots that are preserved during GC. */
57
58 /* Global roots that are preserved during calls to gc. */
59
60 struct ggc_root
61 {
62 struct ggc_root *next;
63 void *base;
64 int nelt;
65 int size;
66 void (*cb) PARAMS ((void *));
67 };
68
69 static struct ggc_root *roots;
70
71 /* Add BASE as a new garbage collection root. It is an array of
72 length NELT with each element SIZE bytes long. CB is a
73 function that will be called with a pointer to each element
74 of the array; it is the intention that CB call the appropriate
75 routine to mark gc-able memory for that element. */
76
77 void
78 ggc_add_root (base, nelt, size, cb)
79 void *base;
80 int nelt, size;
81 void (*cb) PARAMS ((void *));
82 {
83 struct ggc_root *x = (struct ggc_root *) xmalloc (sizeof (*x));
84
85 x->next = roots;
86 x->base = base;
87 x->nelt = nelt;
88 x->size = size;
89 x->cb = cb;
90
91 roots = x;
92 }
93
94 /* Register an array of rtx as a GC root. */
95
96 void
97 ggc_add_rtx_root (base, nelt)
98 rtx *base;
99 int nelt;
100 {
101 ggc_add_root (base, nelt, sizeof (rtx), ggc_mark_rtx_ptr);
102 }
103
104 /* Register an array of trees as a GC root. */
105
106 void
107 ggc_add_tree_root (base, nelt)
108 tree *base;
109 int nelt;
110 {
111 ggc_add_root (base, nelt, sizeof (tree), ggc_mark_tree_ptr);
112 }
113
114 /* Register a varray of rtxs as a GC root. */
115
116 void
117 ggc_add_rtx_varray_root (base, nelt)
118 varray_type *base;
119 int nelt;
120 {
121 ggc_add_root (base, nelt, sizeof (varray_type),
122 ggc_mark_rtx_varray_ptr);
123 }
124
125 /* Register a varray of trees as a GC root. */
126
127 void
128 ggc_add_tree_varray_root (base, nelt)
129 varray_type *base;
130 int nelt;
131 {
132 ggc_add_root (base, nelt, sizeof (varray_type),
133 ggc_mark_tree_varray_ptr);
134 }
135
136 /* Register a hash table of trees as a GC root. */
137
138 void
139 ggc_add_tree_hash_table_root (base, nelt)
140 struct hash_table **base;
141 int nelt;
142 {
143 ggc_add_root (base, nelt, sizeof (struct hash_table *),
144 ggc_mark_tree_hash_table_ptr);
145 }
146
147 /* Remove the previously registered GC root at BASE. */
148
149 void
150 ggc_del_root (base)
151 void *base;
152 {
153 struct ggc_root *x, **p;
154
155 p = &roots, x = roots;
156 while (x)
157 {
158 if (x->base == base)
159 {
160 *p = x->next;
161 free (x);
162 return;
163 }
164 p = &x->next;
165 x = x->next;
166 }
167
168 abort();
169 }
170
171 /* Add a hash table to be scanned when all roots have been processed. We
172 delete any entry in the table that has not been marked. */
173
174 struct d_htab_root
175 {
176 struct d_htab_root *next;
177 htab_t htab;
178 ggc_htab_marked_p marked_p;
179 ggc_htab_mark mark;
180 };
181
182 static struct d_htab_root *d_htab_roots;
183
184 /* Add X, an htab, to a list of htabs that contain objects which are allocated
185 from GC memory. Once all other roots are marked, we check each object in
186 the htab to see if it has already been marked. If not, it is deleted.
187
188 MARKED_P, if specified, is a function that returns 1 if the entry is to
189 be considered as "marked". If not present, the data structure pointed to
190 by the htab slot is tested. This function should be supplied if some
191 other object (such as something pointed to by that object) should be tested
192 in which case the function tests whether that object (or objects) are
193 marked (using ggc_marked_p) and returns nonzero if it is.
194
195 MARK, if specified, is a function that is passed the contents of a slot
196 that has been determined to have been "marked" (via the above function)
197 and marks any other objects pointed to by that object. For example,
198 we might have a hash table of memory attribute blocks, which are pointed
199 to by a MEM RTL but have a pointer to a DECL. MARKED_P in that case will
200 not be specified because we want to know if the attribute block is pointed
201 to by the MEM, but MARK must be specified because if the block has been
202 marked, we need to mark the DECL. */
203
204 void
205 ggc_add_deletable_htab (x, marked_p, mark)
206 PTR x;
207 ggc_htab_marked_p marked_p;
208 ggc_htab_mark mark;
209 {
210 struct d_htab_root *r
211 = (struct d_htab_root *) xmalloc (sizeof (struct d_htab_root));
212
213 r->next = d_htab_roots;
214 r->htab = (htab_t) x;
215 r->marked_p = marked_p ? marked_p : ggc_marked_p;
216 r->mark = mark;
217 d_htab_roots = r;
218 }
219
220 /* Process a slot of an htab by deleting it if it has not been marked. */
221
222 static int
223 ggc_htab_delete (slot, info)
224 void **slot;
225 void *info;
226 {
227 struct d_htab_root *r = (struct d_htab_root *) info;
228
229 if (! (*r->marked_p) (*slot))
230 htab_clear_slot (r->htab, slot);
231 else if (r->mark)
232 (*r->mark) (*slot);
233
234 return 1;
235 }
236
237 /* Iterate through all registered roots and mark each element. */
238
239 void
240 ggc_mark_roots ()
241 {
242 struct ggc_root *x;
243 struct d_htab_root *y;
244
245 VARRAY_TREE_INIT (ggc_pending_trees, 4096, "ggc_pending_trees");
246
247 for (x = roots; x != NULL; x = x->next)
248 {
249 char *elt = x->base;
250 int s = x->size, n = x->nelt;
251 void (*cb) PARAMS ((void *)) = x->cb;
252 int i;
253
254 for (i = 0; i < n; ++i, elt += s)
255 (*cb)(elt);
256 }
257
258 /* Mark all the queued up trees, and their children. */
259 ggc_mark_trees ();
260 VARRAY_FREE (ggc_pending_trees);
261
262 /* Now scan all hash tables that have objects which are to be deleted if
263 they are not already marked. Since these may mark more trees, we need
264 to reinitialize that varray. */
265 VARRAY_TREE_INIT (ggc_pending_trees, 1024, "ggc_pending_trees");
266
267 for (y = d_htab_roots; y != NULL; y = y->next)
268 htab_traverse (y->htab, ggc_htab_delete, (PTR) y);
269 ggc_mark_trees ();
270 VARRAY_FREE (ggc_pending_trees);
271 }
272
273 /* R had not been previously marked, but has now been marked via
274 ggc_set_mark. Now recurse and process the children. */
275
276 void
277 ggc_mark_rtx_children (r)
278 rtx r;
279 {
280 const char *fmt;
281 int i;
282 rtx next_rtx;
283
284 do
285 {
286 enum rtx_code code = GET_CODE (r);
287 /* This gets set to a child rtx to eliminate tail recursion. */
288 next_rtx = NULL;
289
290 /* Collect statistics, if appropriate. */
291 if (ggc_stats)
292 {
293 ++ggc_stats->num_rtxs[(int) code];
294 ggc_stats->size_rtxs[(int) code] += ggc_get_size (r);
295 }
296
297 /* ??? If (some of) these are really pass-dependent info, do we
298 have any right poking our noses in? */
299 switch (code)
300 {
301 case MEM:
302 ggc_mark (MEM_ATTRS (r));
303 break;
304 case JUMP_INSN:
305 ggc_mark_rtx (JUMP_LABEL (r));
306 break;
307 case CODE_LABEL:
308 ggc_mark_rtx (LABEL_REFS (r));
309 break;
310 case LABEL_REF:
311 ggc_mark_rtx (LABEL_NEXTREF (r));
312 ggc_mark_rtx (CONTAINING_INSN (r));
313 break;
314 case ADDRESSOF:
315 ggc_mark_tree (ADDRESSOF_DECL (r));
316 break;
317 case CONST_DOUBLE:
318 ggc_mark_rtx (CONST_DOUBLE_CHAIN (r));
319 break;
320 case NOTE:
321 switch (NOTE_LINE_NUMBER (r))
322 {
323 case NOTE_INSN_RANGE_BEG:
324 case NOTE_INSN_RANGE_END:
325 case NOTE_INSN_LIVE:
326 case NOTE_INSN_EXPECTED_VALUE:
327 ggc_mark_rtx (NOTE_RANGE_INFO (r));
328 break;
329
330 case NOTE_INSN_BLOCK_BEG:
331 case NOTE_INSN_BLOCK_END:
332 ggc_mark_tree (NOTE_BLOCK (r));
333 break;
334
335 default:
336 break;
337 }
338 break;
339
340 default:
341 break;
342 }
343
344 for (fmt = GET_RTX_FORMAT (GET_CODE (r)), i = 0; *fmt ; ++fmt, ++i)
345 {
346 rtx exp;
347 switch (*fmt)
348 {
349 case 'e': case 'u':
350 exp = XEXP (r, i);
351 if (ggc_test_and_set_mark (exp))
352 {
353 if (next_rtx == NULL)
354 next_rtx = exp;
355 else
356 ggc_mark_rtx_children (exp);
357 }
358 break;
359 case 'V': case 'E':
360 ggc_mark_rtvec (XVEC (r, i));
361 break;
362 }
363 }
364 }
365 while ((r = next_rtx) != NULL);
366 }
367
368 /* V had not been previously marked, but has now been marked via
369 ggc_set_mark. Now recurse and process the children. */
370
371 void
372 ggc_mark_rtvec_children (v)
373 rtvec v;
374 {
375 int i;
376
377 i = GET_NUM_ELEM (v);
378 while (--i >= 0)
379 ggc_mark_rtx (RTVEC_ELT (v, i));
380 }
381
382 /* Recursively set marks on all of the children of the
383 GCC_PENDING_TREES. */
384
385 static void
386 ggc_mark_trees ()
387 {
388 while (ggc_pending_trees->elements_used)
389 {
390 tree t;
391 enum tree_code code;
392
393 t = VARRAY_TOP_TREE (ggc_pending_trees);
394 VARRAY_POP (ggc_pending_trees);
395 code = TREE_CODE (t);
396
397 /* Collect statistics, if appropriate. */
398 if (ggc_stats)
399 {
400 ++ggc_stats->num_trees[(int) code];
401 ggc_stats->size_trees[(int) code] += ggc_get_size (t);
402 }
403
404 /* Bits from common. */
405 ggc_mark_tree (TREE_TYPE (t));
406 ggc_mark_tree (TREE_CHAIN (t));
407
408 /* Some nodes require special handling. */
409 switch (code)
410 {
411 case TREE_LIST:
412 ggc_mark_tree (TREE_PURPOSE (t));
413 ggc_mark_tree (TREE_VALUE (t));
414 continue;
415
416 case TREE_VEC:
417 {
418 int i = TREE_VEC_LENGTH (t);
419
420 while (--i >= 0)
421 ggc_mark_tree (TREE_VEC_ELT (t, i));
422 continue;
423 }
424
425 case COMPLEX_CST:
426 ggc_mark_tree (TREE_REALPART (t));
427 ggc_mark_tree (TREE_IMAGPART (t));
428 break;
429
430 case PARM_DECL:
431 ggc_mark_rtx (DECL_INCOMING_RTL (t));
432 break;
433
434 case FIELD_DECL:
435 ggc_mark_tree (DECL_FIELD_BIT_OFFSET (t));
436 break;
437
438 case IDENTIFIER_NODE:
439 lang_mark_tree (t);
440 continue;
441
442 default:
443 break;
444 }
445
446 /* But in general we can handle them by class. */
447 switch (TREE_CODE_CLASS (code))
448 {
449 case 'd': /* A decl node. */
450 ggc_mark_tree (DECL_SIZE (t));
451 ggc_mark_tree (DECL_SIZE_UNIT (t));
452 ggc_mark_tree (DECL_NAME (t));
453 ggc_mark_tree (DECL_CONTEXT (t));
454 ggc_mark_tree (DECL_ARGUMENTS (t));
455 ggc_mark_tree (DECL_RESULT_FLD (t));
456 ggc_mark_tree (DECL_INITIAL (t));
457 ggc_mark_tree (DECL_ABSTRACT_ORIGIN (t));
458 ggc_mark_tree (DECL_SECTION_NAME (t));
459 ggc_mark_tree (DECL_ATTRIBUTES (t));
460 if (DECL_RTL_SET_P (t))
461 ggc_mark_rtx (DECL_RTL (t));
462 ggc_mark_rtx (DECL_LIVE_RANGE_RTL (t));
463 ggc_mark_tree (DECL_VINDEX (t));
464 if (DECL_ASSEMBLER_NAME_SET_P (t))
465 ggc_mark_tree (DECL_ASSEMBLER_NAME (t));
466 if (TREE_CODE (t) == FUNCTION_DECL && DECL_SAVED_INSNS (t))
467 ggc_mark_struct_function (DECL_SAVED_INSNS (t));
468 lang_mark_tree (t);
469 break;
470
471 case 't': /* A type node. */
472 ggc_mark_tree (TYPE_SIZE (t));
473 ggc_mark_tree (TYPE_SIZE_UNIT (t));
474 ggc_mark_tree (TYPE_ATTRIBUTES (t));
475 ggc_mark_tree (TYPE_VALUES (t));
476 ggc_mark_tree (TYPE_POINTER_TO (t));
477 ggc_mark_tree (TYPE_REFERENCE_TO (t));
478 ggc_mark_tree (TYPE_NAME (t));
479 ggc_mark_tree (TYPE_MIN_VALUE (t));
480 ggc_mark_tree (TYPE_MAX_VALUE (t));
481 ggc_mark_tree (TYPE_NEXT_VARIANT (t));
482 ggc_mark_tree (TYPE_MAIN_VARIANT (t));
483 ggc_mark_tree (TYPE_BINFO (t));
484 ggc_mark_tree (TYPE_CONTEXT (t));
485 lang_mark_tree (t);
486 break;
487
488 case 'b': /* A lexical block. */
489 ggc_mark_tree (BLOCK_VARS (t));
490 ggc_mark_tree (BLOCK_SUBBLOCKS (t));
491 ggc_mark_tree (BLOCK_SUPERCONTEXT (t));
492 ggc_mark_tree (BLOCK_ABSTRACT_ORIGIN (t));
493 break;
494
495 case 'c': /* A constant. */
496 ggc_mark_rtx (TREE_CST_RTL (t));
497 break;
498
499 case 'r': case '<': case '1':
500 case '2': case 'e': case 's': /* Expressions. */
501 {
502 int i = TREE_CODE_LENGTH (TREE_CODE (t));
503 int first_rtl = first_rtl_op (TREE_CODE (t));
504
505 while (--i >= 0)
506 {
507 if (i >= first_rtl)
508 ggc_mark_rtx ((rtx) TREE_OPERAND (t, i));
509 else
510 ggc_mark_tree (TREE_OPERAND (t, i));
511 }
512 break;
513 }
514
515 case 'x':
516 lang_mark_tree (t);
517 break;
518 }
519 }
520 }
521
522 /* Mark all the elements of the varray V, which contains rtxs. */
523
524 void
525 ggc_mark_rtx_varray (v)
526 varray_type v;
527 {
528 int i;
529
530 if (v)
531 for (i = v->num_elements - 1; i >= 0; --i)
532 ggc_mark_rtx (VARRAY_RTX (v, i));
533 }
534
535 /* Mark all the elements of the varray V, which contains trees. */
536
537 void
538 ggc_mark_tree_varray (v)
539 varray_type v;
540 {
541 int i;
542
543 if (v)
544 for (i = v->num_elements - 1; i >= 0; --i)
545 ggc_mark_tree (VARRAY_TREE (v, i));
546 }
547
548 /* Mark the hash table-entry HE. Its key field is really a tree. */
549
550 static bool
551 ggc_mark_tree_hash_table_entry (he, k)
552 struct hash_entry *he;
553 hash_table_key k ATTRIBUTE_UNUSED;
554 {
555 ggc_mark_tree ((tree) he->key);
556 return true;
557 }
558
559 /* Mark all the elements of the hash-table H, which contains trees. */
560
561 void
562 ggc_mark_tree_hash_table (ht)
563 struct hash_table *ht;
564 {
565 hash_traverse (ht, ggc_mark_tree_hash_table_entry, /*info=*/0);
566 }
567
568 /* Type-correct function to pass to ggc_add_root. It just forwards
569 *ELT (which is an rtx) to ggc_mark_rtx. */
570
571 static void
572 ggc_mark_rtx_ptr (elt)
573 void *elt;
574 {
575 ggc_mark_rtx (*(rtx *) elt);
576 }
577
578 /* Type-correct function to pass to ggc_add_root. It just forwards
579 *ELT (which is a tree) to ggc_mark_tree. */
580
581 static void
582 ggc_mark_tree_ptr (elt)
583 void *elt;
584 {
585 ggc_mark_tree (*(tree *) elt);
586 }
587
588 /* Type-correct function to pass to ggc_add_root. It just forwards
589 ELT (which is really a varray_type *) to ggc_mark_rtx_varray. */
590
591 static void
592 ggc_mark_rtx_varray_ptr (elt)
593 void *elt;
594 {
595 ggc_mark_rtx_varray (*(varray_type *) elt);
596 }
597
598 /* Type-correct function to pass to ggc_add_root. It just forwards
599 ELT (which is really a varray_type *) to ggc_mark_tree_varray. */
600
601 static void
602 ggc_mark_tree_varray_ptr (elt)
603 void *elt;
604 {
605 ggc_mark_tree_varray (*(varray_type *) elt);
606 }
607
608 /* Type-correct function to pass to ggc_add_root. It just forwards
609 ELT (which is really a struct hash_table **) to
610 ggc_mark_tree_hash_table. */
611
612 static void
613 ggc_mark_tree_hash_table_ptr (elt)
614 void *elt;
615 {
616 ggc_mark_tree_hash_table (*(struct hash_table **) elt);
617 }
618
619 /* Allocate a block of memory, then clear it. */
620 void *
621 ggc_alloc_cleared (size)
622 size_t size;
623 {
624 void *buf = ggc_alloc (size);
625 memset (buf, 0, size);
626 return buf;
627 }
628
629 /* Print statistics that are independent of the collector in use. */
630 #define SCALE(x) ((unsigned long) ((x) < 1024*10 \
631 ? (x) \
632 : ((x) < 1024*1024*10 \
633 ? (x) / 1024 \
634 : (x) / (1024*1024))))
635 #define LABEL(x) ((x) < 1024*10 ? ' ' : ((x) < 1024*1024*10 ? 'k' : 'M'))
636
637 void
638 ggc_print_common_statistics (stream, stats)
639 FILE *stream;
640 ggc_statistics *stats;
641 {
642 int code;
643
644 /* Set the pointer so that during collection we will actually gather
645 the statistics. */
646 ggc_stats = stats;
647
648 /* Then do one collection to fill in the statistics. */
649 ggc_collect ();
650
651 /* Total the statistics. */
652 for (code = 0; code < MAX_TREE_CODES; ++code)
653 {
654 stats->total_num_trees += stats->num_trees[code];
655 stats->total_size_trees += stats->size_trees[code];
656 }
657 for (code = 0; code < NUM_RTX_CODE; ++code)
658 {
659 stats->total_num_rtxs += stats->num_rtxs[code];
660 stats->total_size_rtxs += stats->size_rtxs[code];
661 }
662
663 /* Print the statistics for trees. */
664 fprintf (stream, "\n%-17s%10s %16s %10s\n", "Tree",
665 "Number", "Bytes", "% Total");
666 for (code = 0; code < MAX_TREE_CODES; ++code)
667 if (ggc_stats->num_trees[code])
668 {
669 fprintf (stream, "%-17s%10u%16ld%c %10.3f\n",
670 tree_code_name[code],
671 ggc_stats->num_trees[code],
672 SCALE (ggc_stats->size_trees[code]),
673 LABEL (ggc_stats->size_trees[code]),
674 (100 * ((double) ggc_stats->size_trees[code])
675 / ggc_stats->total_size_trees));
676 }
677 fprintf (stream,
678 "%-17s%10u%16ld%c\n", "Total",
679 ggc_stats->total_num_trees,
680 SCALE (ggc_stats->total_size_trees),
681 LABEL (ggc_stats->total_size_trees));
682
683 /* Print the statistics for RTL. */
684 fprintf (stream, "\n%-17s%10s %16s %10s\n", "RTX",
685 "Number", "Bytes", "% Total");
686 for (code = 0; code < NUM_RTX_CODE; ++code)
687 if (ggc_stats->num_rtxs[code])
688 {
689 fprintf (stream, "%-17s%10u%16ld%c %10.3f\n",
690 rtx_name[code],
691 ggc_stats->num_rtxs[code],
692 SCALE (ggc_stats->size_rtxs[code]),
693 LABEL (ggc_stats->size_rtxs[code]),
694 (100 * ((double) ggc_stats->size_rtxs[code])
695 / ggc_stats->total_size_rtxs));
696 }
697 fprintf (stream,
698 "%-17s%10u%16ld%c\n", "Total",
699 ggc_stats->total_num_rtxs,
700 SCALE (ggc_stats->total_size_rtxs),
701 LABEL (ggc_stats->total_size_rtxs));
702
703 /* Don't gather statistics any more. */
704 ggc_stats = NULL;
705 }