1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
|
/* "Bag-of-pages" zone garbage collector for the GNU compiler.
Copyright (C) 1999, 2000, 2001, 2002, 2003 Free Software Foundation, Inc.
Contributed by Richard Henderson (rth@redhat.com) and Daniel Berlin (dberlin@dberlin.org)
This file is part of GCC.
GCC is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free
Software Foundation; either version 2, or (at your option) any later
version.
GCC is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
for more details.
You should have received a copy of the GNU General Public License
along with GCC; see the file COPYING. If not, write to the Free
Software Foundation, 59 Temple Place - Suite 330, Boston, MA
02111-1307, USA. */
#include "config.h"
#include "system.h"
#include "coretypes.h"
#include "tm.h"
#include "tree.h"
#include "rtl.h"
#include "tm_p.h"
#include "toplev.h"
#include "varray.h"
#include "flags.h"
#include "ggc.h"
#include "timevar.h"
#include "params.h"
#include "bitmap.h"
#ifdef ENABLE_VALGRIND_CHECKING
# ifdef HAVE_VALGRIND_MEMCHECK_H
# include <valgrind/memcheck.h>
# elif defined HAVE_MEMCHECK_H
# include <memcheck.h>
# else
# include <valgrind.h>
# endif
#else
/* Avoid #ifdef:s when we can help it. */
#define VALGRIND_DISCARD(x)
#define VALGRIND_MALLOCLIKE_BLOCK(w,x,y,z)
#define VALGRIND_FREELIKE_BLOCK(x,y)
#endif
/* Prefer MAP_ANON(YMOUS) to /dev/zero, since we don't need to keep a
file open. Prefer either to valloc. */
#ifdef HAVE_MMAP_ANON
# undef HAVE_MMAP_DEV_ZERO
# include <sys/mman.h>
# ifndef MAP_FAILED
# define MAP_FAILED -1
# endif
# if !defined (MAP_ANONYMOUS) && defined (MAP_ANON)
# define MAP_ANONYMOUS MAP_ANON
# endif
# define USING_MMAP
#endif
#ifdef HAVE_MMAP_DEV_ZERO
# include <sys/mman.h>
# ifndef MAP_FAILED
# define MAP_FAILED -1
# endif
# define USING_MMAP
#endif
#ifndef USING_MMAP
#define USING_MALLOC_PAGE_GROUPS
#endif
#if (GCC_VERSION < 3001)
#define prefetch(X) ((void) X)
#else
#define prefetch(X) __builtin_prefetch (X)
#endif
/* NOTES:
If we track inter-zone pointers, we can mark single zones at a
time.
If we have a zone where we guarantee no inter-zone pointers, we
could mark that zone seperately.
The garbage zone should not be marked, and we should return 1 in
ggc_set_mark for any object in the garbage zone, which cuts off
marking quickly. */
/* Stategy:
This garbage-collecting allocator segregates objects into zones.
It also segregates objects into "large" and "small" bins. Large
objects are greater or equal to page size.
Pages for small objects are broken up into chunks, each of which
are described by a struct alloc_chunk. One can walk over all
chunks on the page by adding the chunk size to the chunk's data
address. The free space for a page exists in the free chunk bins.
Each page-entry also has a context depth, which is used to track
pushing and popping of allocation contexts. Only objects allocated
in the current (highest-numbered) context may be collected.
Empty pages (of all sizes) are kept on a single page cache list,
and are considered first when new pages are required; they are
deallocated at the start of the next collection if they haven't
been recycled by then. */
/* Define GGC_DEBUG_LEVEL to print debugging information.
0: No debugging output.
1: GC statistics only.
2: Page-entry allocations/deallocations as well.
3: Object allocations as well.
4: Object marks as well. */
#define GGC_DEBUG_LEVEL (0)
#ifndef HOST_BITS_PER_PTR
#define HOST_BITS_PER_PTR HOST_BITS_PER_LONG
#endif
#ifdef COOKIE_CHECKING
#define CHUNK_MAGIC 0x95321123
#define DEADCHUNK_MAGIC 0x12817317
#endif
/* This structure manages small chunks. When the chunk is free, it's
linked with other chunks via free_next. When the chunk is allocated,
the data starts at u. Large chunks are allocated one at a time to
their own page, and so don't come in here.
The "type" field is a placeholder for a future change to do
generational collection. At present it is 0 when free and
and 1 when allocated. */
struct alloc_chunk {
#ifdef COOKIE_CHECKING
unsigned int magic;
#endif
unsigned int type:1;
unsigned int typecode:15;
unsigned int size:15;
unsigned int mark:1;
union {
struct alloc_chunk *next_free;
char data[1];
/* Make sure the data is sufficiently aligned. */
HOST_WIDEST_INT align_i;
#ifdef HAVE_LONG_DOUBLE
long double align_d;
#else
double align_d;
#endif
} u;
} __attribute__ ((packed));
#define CHUNK_OVERHEAD (offsetof (struct alloc_chunk, u))
/* We maintain several bins of free lists for chunks for very small
objects. We never exhaustively search other bins -- if we don't
find one of the proper size, we allocate from the "larger" bin. */
/* Decreasing the number of free bins increases the time it takes to allocate.
Similar with increasing max_free_bin_size without increasing num_free_bins.
After much histogramming of allocation sizes and time spent on gc,
on a powerpc G4 7450 - 667 mhz, and an pentium 4 - 2.8ghz,
these were determined to be the optimal values. */
#define NUM_FREE_BINS 64
#define MAX_FREE_BIN_SIZE 256
#define FREE_BIN_DELTA (MAX_FREE_BIN_SIZE / NUM_FREE_BINS)
#define SIZE_BIN_UP(SIZE) (((SIZE) + FREE_BIN_DELTA - 1) / FREE_BIN_DELTA)
#define SIZE_BIN_DOWN(SIZE) ((SIZE) / FREE_BIN_DELTA)
/* Marker used as chunk->size for a large object. Should correspond
to the size of the bitfield above. */
#define LARGE_OBJECT_SIZE 0x7fff
/* We use this structure to determine the alignment required for
allocations. For power-of-two sized allocations, that's not a
problem, but it does matter for odd-sized allocations. */
struct max_alignment {
char c;
union {
HOST_WIDEST_INT i;
#ifdef HAVE_LONG_DOUBLE
long double d;
#else
double d;
#endif
} u;
};
/* The biggest alignment required. */
#define MAX_ALIGNMENT (offsetof (struct max_alignment, u))
/* Compute the smallest nonnegative number which when added to X gives
a multiple of F. */
#define ROUND_UP_VALUE(x, f) ((f) - 1 - ((f) - 1 + (x)) % (f))
/* Compute the smallest multiple of F that is >= X. */
#define ROUND_UP(x, f) (CEIL (x, f) * (f))
/* A two-level tree is used to look up the page-entry for a given
pointer. Two chunks of the pointer's bits are extracted to index
the first and second levels of the tree, as follows:
HOST_PAGE_SIZE_BITS
32 | |
msb +----------------+----+------+------+ lsb
| | |
PAGE_L1_BITS |
| |
PAGE_L2_BITS
The bottommost HOST_PAGE_SIZE_BITS are ignored, since page-entry
pages are aligned on system page boundaries. The next most
significant PAGE_L2_BITS and PAGE_L1_BITS are the second and first
index values in the lookup table, respectively.
For 32-bit architectures and the settings below, there are no
leftover bits. For architectures with wider pointers, the lookup
tree points to a list of pages, which must be scanned to find the
correct one. */
#define PAGE_L1_BITS (8)
#define PAGE_L2_BITS (32 - PAGE_L1_BITS - G.lg_pagesize)
#define PAGE_L1_SIZE ((size_t) 1 << PAGE_L1_BITS)
#define PAGE_L2_SIZE ((size_t) 1 << PAGE_L2_BITS)
#define LOOKUP_L1(p) \
(((size_t) (p) >> (32 - PAGE_L1_BITS)) & ((1 << PAGE_L1_BITS) - 1))
#define LOOKUP_L2(p) \
(((size_t) (p) >> G.lg_pagesize) & ((1 << PAGE_L2_BITS) - 1))
struct alloc_zone;
/* A page_entry records the status of an allocation page. */
typedef struct page_entry
{
/* The next page-entry with objects of the same size, or NULL if
this is the last page-entry. */
struct page_entry *next;
/* The number of bytes allocated. (This will always be a multiple
of the host system page size.) */
size_t bytes;
/* How many collections we've survived. */
size_t survived;
/* The address at which the memory is allocated. */
char *page;
#ifdef USING_MALLOC_PAGE_GROUPS
/* Back pointer to the page group this page came from. */
struct page_group *group;
#endif
/* Number of bytes on the page unallocated. Only used during
collection, and even then large pages merely set this non-zero. */
size_t bytes_free;
/* Context depth of this page. */
unsigned short context_depth;
/* Does this page contain small objects, or one large object? */
bool large_p;
/* The zone that this page entry belongs to. */
struct alloc_zone *zone;
} page_entry;
#ifdef USING_MALLOC_PAGE_GROUPS
/* A page_group describes a large allocation from malloc, from which
we parcel out aligned pages. */
typedef struct page_group
{
/* A linked list of all extant page groups. */
struct page_group *next;
/* The address we received from malloc. */
char *allocation;
/* The size of the block. */
size_t alloc_size;
/* A bitmask of pages in use. */
unsigned int in_use;
} page_group;
#endif
#if HOST_BITS_PER_PTR <= 32
/* On 32-bit hosts, we use a two level page table, as pictured above. */
typedef page_entry **page_table[PAGE_L1_SIZE];
#else
/* On 64-bit hosts, we use the same two level page tables plus a linked
list that disambiguates the top 32-bits. There will almost always be
exactly one entry in the list. */
typedef struct page_table_chain
{
struct page_table_chain *next;
size_t high_bits;
page_entry **table[PAGE_L1_SIZE];
} *page_table;
#endif
/* The global variables. */
static struct globals
{
/* The page lookup table. A single page can only belong to one
zone. This means free pages are zone-specific ATM. */
page_table lookup;
/* The linked list of zones. */
struct alloc_zone *zones;
/* The system's page size. */
size_t pagesize;
size_t lg_pagesize;
/* A file descriptor open to /dev/zero for reading. */
#if defined (HAVE_MMAP_DEV_ZERO)
int dev_zero_fd;
#endif
/* The file descriptor for debugging output. */
FILE *debug_file;
} G;
/* The zone allocation structure. */
struct alloc_zone
{
/* Name of the zone. */
const char *name;
/* Linked list of pages in a zone. */
page_entry *pages;
/* Linked lists of free storage. Slots 1 ... NUM_FREE_BINS have chunks of size
FREE_BIN_DELTA. All other chunks are in slot 0. */
struct alloc_chunk *free_chunks[NUM_FREE_BINS + 1];
/* Bytes currently allocated. */
size_t allocated;
/* Bytes currently allocated at the end of the last collection. */
size_t allocated_last_gc;
/* Total amount of memory mapped. */
size_t bytes_mapped;
/* Bit N set if any allocations have been done at context depth N. */
unsigned long context_depth_allocations;
/* Bit N set if any collections have been done at context depth N. */
unsigned long context_depth_collections;
/* The current depth in the context stack. */
unsigned short context_depth;
/* A cache of free system pages. */
page_entry *free_pages;
#ifdef USING_MALLOC_PAGE_GROUPS
page_group *page_groups;
#endif
/* Next zone in the linked list of zones. */
struct alloc_zone *next_zone;
/* Return true if this zone was collected during this collection. */
bool was_collected;
} main_zone;
struct alloc_zone *rtl_zone;
struct alloc_zone *garbage_zone;
struct alloc_zone *tree_zone;
/* Allocate pages in chunks of this size, to throttle calls to memory
allocation routines. The first page is used, the rest go onto the
free list. This cannot be larger than HOST_BITS_PER_INT for the
in_use bitmask for page_group. */
#define GGC_QUIRE_SIZE 16
static int ggc_allocated_p (const void *);
static page_entry *lookup_page_table_entry (const void *);
static void set_page_table_entry (void *, page_entry *);
#ifdef USING_MMAP
static char *alloc_anon (char *, size_t, struct alloc_zone *);
#endif
#ifdef USING_MALLOC_PAGE_GROUPS
static size_t page_group_index (char *, char *);
static void set_page_group_in_use (page_group *, char *);
static void clear_page_group_in_use (page_group *, char *);
#endif
static struct page_entry * alloc_small_page ( struct alloc_zone *);
static struct page_entry * alloc_large_page (size_t, struct alloc_zone *);
static void free_chunk (struct alloc_chunk *, size_t, struct alloc_zone *);
static void free_page (struct page_entry *);
static void release_pages (struct alloc_zone *);
static void sweep_pages (struct alloc_zone *);
static void * ggc_alloc_zone_1 (size_t, struct alloc_zone *, short);
static bool ggc_collect_1 (struct alloc_zone *, bool);
static void check_cookies (void);
/* Returns nonzero if P was allocated in GC'able memory. */
static inline int
ggc_allocated_p (const void *p)
{
page_entry ***base;
size_t L1, L2;
#if HOST_BITS_PER_PTR <= 32
base = &G.lookup[0];
#else
page_table table = G.lookup;
size_t high_bits = (size_t) p & ~ (size_t) 0xffffffff;
while (1)
{
if (table == NULL)
return 0;
if (table->high_bits == high_bits)
break;
table = table->next;
}
base = &table->table[0];
#endif
/* Extract the level 1 and 2 indices. */
L1 = LOOKUP_L1 (p);
L2 = LOOKUP_L2 (p);
return base[L1] && base[L1][L2];
}
/* Traverse the page table and find the entry for a page.
Die (probably) if the object wasn't allocated via GC. */
static inline page_entry *
lookup_page_table_entry(const void *p)
{
page_entry ***base;
size_t L1, L2;
#if HOST_BITS_PER_PTR <= 32
base = &G.lookup[0];
#else
page_table table = G.lookup;
size_t high_bits = (size_t) p & ~ (size_t) 0xffffffff;
while (table->high_bits != high_bits)
table = table->next;
base = &table->table[0];
#endif
/* Extract the level 1 and 2 indices. */
L1 = LOOKUP_L1 (p);
L2 = LOOKUP_L2 (p);
return base[L1][L2];
}
/* Set the page table entry for a page. */
static void
set_page_table_entry(void *p, page_entry *entry)
{
page_entry ***base;
size_t L1, L2;
#if HOST_BITS_PER_PTR <= 32
base = &G.lookup[0];
#else
page_table table;
size_t high_bits = (size_t) p & ~ (size_t) 0xffffffff;
for (table = G.lookup; table; table = table->next)
if (table->high_bits == high_bits)
goto found;
/* Not found -- allocate a new table. */
table = (page_table) xcalloc (1, sizeof(*table));
table->next = G.lookup;
table->high_bits = high_bits;
G.lookup = table;
found:
base = &table->table[0];
#endif
/* Extract the level 1 and 2 indices. */
L1 = LOOKUP_L1 (p);
L2 = LOOKUP_L2 (p);
if (base[L1] == NULL)
base[L1] = (page_entry **) xcalloc (PAGE_L2_SIZE, sizeof (page_entry *));
base[L1][L2] = entry;
}
#ifdef USING_MMAP
/* Allocate SIZE bytes of anonymous memory, preferably near PREF,
(if non-null). The ifdef structure here is intended to cause a
compile error unless exactly one of the HAVE_* is defined. */
static inline char *
alloc_anon (char *pref ATTRIBUTE_UNUSED, size_t size, struct alloc_zone *zone)
{
#ifdef HAVE_MMAP_ANON
char *page = (char *) mmap (pref, size, PROT_READ | PROT_WRITE,
MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
#endif
#ifdef HAVE_MMAP_DEV_ZERO
char *page = (char *) mmap (pref, size, PROT_READ | PROT_WRITE,
MAP_PRIVATE, G.dev_zero_fd, 0);
#endif
VALGRIND_MALLOCLIKE_BLOCK(page, size, 0, 0);
if (page == (char *) MAP_FAILED)
{
perror ("virtual memory exhausted");
exit (FATAL_EXIT_CODE);
}
/* Remember that we allocated this memory. */
zone->bytes_mapped += size;
/* Pretend we don't have access to the allocated pages. We'll enable
access to smaller pieces of the area in ggc_alloc. Discard the
handle to avoid handle leak. */
VALGRIND_DISCARD (VALGRIND_MAKE_NOACCESS (page, size));
return page;
}
#endif
#ifdef USING_MALLOC_PAGE_GROUPS
/* Compute the index for this page into the page group. */
static inline size_t
page_group_index (char *allocation, char *page)
{
return (size_t) (page - allocation) >> G.lg_pagesize;
}
/* Set and clear the in_use bit for this page in the page group. */
static inline void
set_page_group_in_use (page_group *group, char *page)
{
group->in_use |= 1 << page_group_index (group->allocation, page);
}
static inline void
clear_page_group_in_use (page_group *group, char *page)
{
group->in_use &= ~(1 << page_group_index (group->allocation, page));
}
#endif
/* Allocate a new page for allocating objects of size 2^ORDER,
and return an entry for it. The entry is not added to the
appropriate page_table list. */
static inline struct page_entry *
alloc_small_page (struct alloc_zone *zone)
{
struct page_entry *entry;
char *page;
#ifdef USING_MALLOC_PAGE_GROUPS
page_group *group;
#endif
page = NULL;
/* Check the list of free pages for one we can use. */
entry = zone->free_pages;
if (entry != NULL)
{
/* Recycle the allocated memory from this page ... */
zone->free_pages = entry->next;
page = entry->page;
#ifdef USING_MALLOC_PAGE_GROUPS
group = entry->group;
#endif
}
#ifdef USING_MMAP
else
{
/* We want just one page. Allocate a bunch of them and put the
extras on the freelist. (Can only do this optimization with
mmap for backing store.) */
struct page_entry *e, *f = zone->free_pages;
int i;
page = alloc_anon (NULL, G.pagesize * GGC_QUIRE_SIZE, zone);
/* This loop counts down so that the chain will be in ascending
memory order. */
for (i = GGC_QUIRE_SIZE - 1; i >= 1; i--)
{
e = (struct page_entry *) xmalloc (sizeof (struct page_entry));
e->bytes = G.pagesize;
e->page = page + (i << G.lg_pagesize);
e->next = f;
f = e;
}
zone->free_pages = f;
}
#endif
#ifdef USING_MALLOC_PAGE_GROUPS
else
{
/* Allocate a large block of memory and serve out the aligned
pages therein. This results in much less memory wastage
than the traditional implementation of valloc. */
char *allocation, *a, *enda;
size_t alloc_size, head_slop, tail_slop;
int multiple_pages = (entry_size == G.pagesize);
if (multiple_pages)
alloc_size = GGC_QUIRE_SIZE * G.pagesize;
else
alloc_size = entry_size + G.pagesize - 1;
allocation = xmalloc (alloc_size);
VALGRIND_MALLOCLIKE_BLOCK(addr, alloc_size, 0, 0);
page = (char *) (((size_t) allocation + G.pagesize - 1) & -G.pagesize);
head_slop = page - allocation;
if (multiple_pages)
tail_slop = ((size_t) allocation + alloc_size) & (G.pagesize - 1);
else
tail_slop = alloc_size - entry_size - head_slop;
enda = allocation + alloc_size - tail_slop;
/* We allocated N pages, which are likely not aligned, leaving
us with N-1 usable pages. We plan to place the page_group
structure somewhere in the slop. */
if (head_slop >= sizeof (page_group))
group = (page_group *)page - 1;
else
{
/* We magically got an aligned allocation. Too bad, we have
to waste a page anyway. */
if (tail_slop == 0)
{
enda -= G.pagesize;
tail_slop += G.pagesize;
}
if (tail_slop < sizeof (page_group))
abort ();
group = (page_group *)enda;
tail_slop -= sizeof (page_group);
}
/* Remember that we allocated this memory. */
group->next = G.page_groups;
group->allocation = allocation;
group->alloc_size = alloc_size;
group->in_use = 0;
zone->page_groups = group;
G.bytes_mapped += alloc_size;
/* If we allocated multiple pages, put the rest on the free list. */
if (multiple_pages)
{
struct page_entry *e, *f = G.free_pages;
for (a = enda - G.pagesize; a != page; a -= G.pagesize)
{
e = (struct page_entry *) xmalloc (sizeof (struct page_entry));
e->bytes = G.pagesize;
e->page = a;
e->group = group;
e->next = f;
f = e;
}
zone->free_pages = f;
}
}
#endif
if (entry == NULL)
entry = (struct page_entry *) xmalloc (sizeof (struct page_entry));
entry->next = 0;
entry->bytes = G.pagesize;
entry->bytes_free = G.pagesize;
entry->page = page;
entry->context_depth = zone->context_depth;
entry->large_p = false;
entry->zone = zone;
zone->context_depth_allocations |= (unsigned long)1 << zone->context_depth;
#ifdef USING_MALLOC_PAGE_GROUPS
entry->group = group;
set_page_group_in_use (group, page);
#endif
set_page_table_entry (page, entry);
if (GGC_DEBUG_LEVEL >= 2)
fprintf (G.debug_file,
"Allocating %s page at %p, data %p-%p\n", entry->zone->name,
(PTR) entry, page, page + G.pagesize - 1);
return entry;
}
/* Allocate a large page of size SIZE in ZONE. */
static inline struct page_entry *
alloc_large_page (size_t size, struct alloc_zone *zone)
{
struct page_entry *entry;
char *page;
page = (char *) xmalloc (size + CHUNK_OVERHEAD + sizeof (struct page_entry));
entry = (struct page_entry *) (page + size + CHUNK_OVERHEAD);
entry->next = 0;
entry->bytes = size;
entry->bytes_free = LARGE_OBJECT_SIZE + CHUNK_OVERHEAD;
entry->page = page;
entry->context_depth = zone->context_depth;
entry->large_p = true;
entry->zone = zone;
zone->context_depth_allocations |= (unsigned long)1 << zone->context_depth;
#ifdef USING_MALLOC_PAGE_GROUPS
entry->group = NULL;
#endif
set_page_table_entry (page, entry);
if (GGC_DEBUG_LEVEL >= 2)
fprintf (G.debug_file,
"Allocating %s large page at %p, data %p-%p\n", entry->zone->name,
(PTR) entry, page, page + size - 1);
return entry;
}
/* For a page that is no longer needed, put it on the free page list. */
static inline void
free_page (page_entry *entry)
{
if (GGC_DEBUG_LEVEL >= 2)
fprintf (G.debug_file,
"Deallocating %s page at %p, data %p-%p\n", entry->zone->name, (PTR) entry,
entry->page, entry->page + entry->bytes - 1);
set_page_table_entry (entry->page, NULL);
if (entry->large_p)
{
free (entry->page);
VALGRIND_FREELIKE_BLOCK (entry->page, entry->bytes);
}
else
{
/* Mark the page as inaccessible. Discard the handle to
avoid handle leak. */
VALGRIND_DISCARD (VALGRIND_MAKE_NOACCESS (entry->page, entry->bytes));
#ifdef USING_MALLOC_PAGE_GROUPS
clear_page_group_in_use (entry->group, entry->page);
#endif
entry->next = entry->zone->free_pages;
entry->zone->free_pages = entry;
}
}
/* Release the free page cache to the system. */
static void
release_pages (struct alloc_zone *zone)
{
#ifdef USING_MMAP
page_entry *p, *next;
char *start;
size_t len;
/* Gather up adjacent pages so they are unmapped together. */
p = zone->free_pages;
while (p)
{
start = p->page;
next = p->next;
len = p->bytes;
free (p);
p = next;
while (p && p->page == start + len)
{
next = p->next;
len += p->bytes;
free (p);
p = next;
}
munmap (start, len);
zone->bytes_mapped -= len;
}
zone->free_pages = NULL;
#endif
#ifdef USING_MALLOC_PAGE_GROUPS
page_entry **pp, *p;
page_group **gp, *g;
/* Remove all pages from free page groups from the list. */
pp = &(zone->free_pages);
while ((p = *pp) != NULL)
if (p->group->in_use == 0)
{
*pp = p->next;
free (p);
}
else
pp = &p->next;
/* Remove all free page groups, and release the storage. */
gp = &(zone->page_groups);
while ((g = *gp) != NULL)
if (g->in_use == 0)
{
*gp = g->next;
zone->bytes_mapped -= g->alloc_size;
free (g->allocation);
VALGRIND_FREELIKE_BLOCK(g->allocation, 0);
}
else
gp = &g->next;
#endif
}
/* Place CHUNK of size SIZE on the free list for ZONE. */
static inline void
free_chunk (struct alloc_chunk *chunk, size_t size, struct alloc_zone *zone)
{
size_t bin = 0;
bin = SIZE_BIN_DOWN (size);
if (bin == 0)
abort ();
if (bin > NUM_FREE_BINS)
bin = 0;
#ifdef COOKIE_CHECKING
if (chunk->magic != CHUNK_MAGIC && chunk->magic != DEADCHUNK_MAGIC)
abort ();
chunk->magic = DEADCHUNK_MAGIC;
#endif
chunk->u.next_free = zone->free_chunks[bin];
zone->free_chunks[bin] = chunk;
if (GGC_DEBUG_LEVEL >= 3)
fprintf (G.debug_file, "Deallocating object, chunk=%p\n", (void *)chunk);
VALGRIND_DISCARD (VALGRIND_MAKE_READABLE (chunk, sizeof (struct alloc_chunk)));
}
/* Allocate a chunk of memory of SIZE bytes. */
static void *
ggc_alloc_zone_1 (size_t size, struct alloc_zone *zone, short type)
{
size_t bin = 0;
size_t lsize = 0;
struct page_entry *entry;
struct alloc_chunk *chunk, *lchunk, **pp;
void *result;
/* Align size, so that we're assured of aligned allocations. */
if (size < FREE_BIN_DELTA)
size = FREE_BIN_DELTA;
size = (size + MAX_ALIGNMENT - 1) & -MAX_ALIGNMENT;
/* Large objects are handled specially. */
if (size >= G.pagesize - 2*CHUNK_OVERHEAD - FREE_BIN_DELTA)
{
entry = alloc_large_page (size, zone);
entry->survived = 0;
entry->next = entry->zone->pages;
entry->zone->pages = entry;
chunk = (struct alloc_chunk *) entry->page;
VALGRIND_DISCARD (VALGRIND_MAKE_WRITABLE (chunk, sizeof (struct alloc_chunk)));
chunk->size = LARGE_OBJECT_SIZE;
goto found;
}
/* First look for a tiny object already segregated into its own
size bucket. */
bin = SIZE_BIN_UP (size);
if (bin <= NUM_FREE_BINS)
{
chunk = zone->free_chunks[bin];
if (chunk)
{
zone->free_chunks[bin] = chunk->u.next_free;
VALGRIND_DISCARD (VALGRIND_MAKE_WRITABLE (chunk, sizeof (struct alloc_chunk)));
goto found;
}
}
/* Failing that, look through the "other" bucket for a chunk
that is large enough. */
pp = &(zone->free_chunks[0]);
chunk = *pp;
while (chunk && chunk->size < size)
{
pp = &chunk->u.next_free;
chunk = *pp;
}
/* Failing that, allocate new storage. */
if (!chunk)
{
entry = alloc_small_page (zone);
entry->next = entry->zone->pages;
entry->zone->pages = entry;
chunk = (struct alloc_chunk *) entry->page;
VALGRIND_DISCARD (VALGRIND_MAKE_WRITABLE (chunk, sizeof (struct alloc_chunk)));
chunk->size = G.pagesize - CHUNK_OVERHEAD;
}
else
{
*pp = chunk->u.next_free;
VALGRIND_DISCARD (VALGRIND_MAKE_WRITABLE (chunk, sizeof (struct alloc_chunk)));
}
/* Release extra memory from a chunk that's too big. */
lsize = chunk->size - size;
if (lsize >= CHUNK_OVERHEAD + FREE_BIN_DELTA)
{
VALGRIND_DISCARD (VALGRIND_MAKE_WRITABLE (chunk, sizeof (struct alloc_chunk)));
chunk->size = size;
lsize -= CHUNK_OVERHEAD;
lchunk = (struct alloc_chunk *)(chunk->u.data + size);
VALGRIND_DISCARD (VALGRIND_MAKE_WRITABLE (lchunk, sizeof (struct alloc_chunk)));
#ifdef COOKIE_CHECKING
lchunk->magic = CHUNK_MAGIC;
#endif
lchunk->type = 0;
lchunk->mark = 0;
lchunk->size = lsize;
free_chunk (lchunk, lsize, zone);
}
/* Calculate the object's address. */
found:
#ifdef COOKIE_CHECKING
chunk->magic = CHUNK_MAGIC;
#endif
chunk->type = 1;
chunk->mark = 0;
chunk->typecode = type;
result = chunk->u.data;
#ifdef ENABLE_GC_CHECKING
/* Keep poisoning-by-writing-0xaf the object, in an attempt to keep the
exact same semantics in presence of memory bugs, regardless of
ENABLE_VALGRIND_CHECKING. We override this request below. Drop the
handle to avoid handle leak. */
VALGRIND_DISCARD (VALGRIND_MAKE_WRITABLE (result, size));
/* `Poison' the entire allocated object. */
memset (result, 0xaf, size);
#endif
/* Tell Valgrind that the memory is there, but its content isn't
defined. The bytes at the end of the object are still marked
unaccessible. */
VALGRIND_DISCARD (VALGRIND_MAKE_WRITABLE (result, size));
/* Keep track of how many bytes are being allocated. This
information is used in deciding when to collect. */
zone->allocated += size + CHUNK_OVERHEAD;
if (GGC_DEBUG_LEVEL >= 3)
fprintf (G.debug_file, "Allocating object, chunk=%p size=%lu at %p\n",
(void *)chunk, (unsigned long) size, result);
return result;
}
/* Allocate a SIZE of chunk memory of GTE type, into an appropriate zone
for that type. */
void *
ggc_alloc_typed (enum gt_types_enum gte, size_t size)
{
switch (gte)
{
case gt_ggc_e_14lang_tree_node:
return ggc_alloc_zone_1 (size, tree_zone, gte);
case gt_ggc_e_7rtx_def:
return ggc_alloc_zone_1 (size, rtl_zone, gte);
case gt_ggc_e_9rtvec_def:
return ggc_alloc_zone_1 (size, rtl_zone, gte);
default:
return ggc_alloc_zone_1 (size, &main_zone, gte);
}
}
/* Normal ggc_alloc simply allocates into the main zone. */
void *
ggc_alloc (size_t size)
{
return ggc_alloc_zone_1 (size, &main_zone, -1);
}
/* Zone allocation allocates into the specified zone. */
void *
ggc_alloc_zone (size_t size, struct alloc_zone *zone)
{
return ggc_alloc_zone_1 (size, zone, -1);
}
/* If P is not marked, mark it and return false. Otherwise return true.
P must have been allocated by the GC allocator; it mustn't point to
static objects, stack variables, or memory allocated with malloc. */
int
ggc_set_mark (const void *p)
{
page_entry *entry;
struct alloc_chunk *chunk;
#ifdef ENABLE_CHECKING
/* Look up the page on which the object is alloced. If the object
wasn't allocated by the collector, we'll probably die. */
entry = lookup_page_table_entry (p);
if (entry == NULL)
abort ();
#endif
chunk = (struct alloc_chunk *) ((char *)p - CHUNK_OVERHEAD);
#ifdef COOKIE_CHECKING
if (chunk->magic != CHUNK_MAGIC)
abort ();
#endif
if (chunk->mark)
return 1;
chunk->mark = 1;
#ifndef ENABLE_CHECKING
entry = lookup_page_table_entry (p);
#endif
/* Large pages are either completely full or completely empty. So if
they are marked, they are completely full. */
if (entry->large_p)
entry->bytes_free = 0;
else
entry->bytes_free -= chunk->size + CHUNK_OVERHEAD;
if (GGC_DEBUG_LEVEL >= 4)
fprintf (G.debug_file, "Marking %p\n", p);
return 0;
}
/* Return 1 if P has been marked, zero otherwise.
P must have been allocated by the GC allocator; it mustn't point to
static objects, stack variables, or memory allocated with malloc. */
int
ggc_marked_p (const void *p)
{
struct alloc_chunk *chunk;
#ifdef ENABLE_CHECKING
{
page_entry *entry = lookup_page_table_entry (p);
if (entry == NULL)
abort ();
}
#endif
chunk = (struct alloc_chunk *) ((char *)p - CHUNK_OVERHEAD);
#ifdef COOKIE_CHECKING
if (chunk->magic != CHUNK_MAGIC)
abort ();
#endif
return chunk->mark;
}
/* Return the size of the gc-able object P. */
size_t
ggc_get_size (const void *p)
{
struct alloc_chunk *chunk;
struct page_entry *entry;
#ifdef ENABLE_CHECKING
entry = lookup_page_table_entry (p);
if (entry == NULL)
abort ();
#endif
chunk = (struct alloc_chunk *) ((char *)p - CHUNK_OVERHEAD);
#ifdef COOKIE_CHECKING
if (chunk->magic != CHUNK_MAGIC)
abort ();
#endif
if (chunk->size == LARGE_OBJECT_SIZE)
{
#ifndef ENABLE_CHECKING
entry = lookup_page_table_entry (p);
#endif
return entry->bytes;
}
return chunk->size;
}
/* Initialize the ggc-zone-mmap allocator. */
void
init_ggc (void)
{
/* Set up the main zone by hand. */
main_zone.name = "Main zone";
G.zones = &main_zone;
/* Allocate the default zones. */
rtl_zone = new_ggc_zone ("RTL zone");
tree_zone = new_ggc_zone ("Tree zone");
garbage_zone = new_ggc_zone ("Garbage zone");
G.pagesize = getpagesize();
G.lg_pagesize = exact_log2 (G.pagesize);
#ifdef HAVE_MMAP_DEV_ZERO
G.dev_zero_fd = open ("/dev/zero", O_RDONLY);
if (G.dev_zero_fd == -1)
abort ();
#endif
#if 0
G.debug_file = fopen ("ggc-mmap.debug", "w");
setlinebuf (G.debug_file);
#else
G.debug_file = stdout;
#endif
#ifdef USING_MMAP
/* StunOS has an amazing off-by-one error for the first mmap allocation
after fiddling with RLIMIT_STACK. The result, as hard as it is to
believe, is an unaligned page allocation, which would cause us to
hork badly if we tried to use it. */
{
char *p = alloc_anon (NULL, G.pagesize, &main_zone);
struct page_entry *e;
if ((size_t)p & (G.pagesize - 1))
{
/* How losing. Discard this one and try another. If we still
can't get something useful, give up. */
p = alloc_anon (NULL, G.pagesize, &main_zone);
if ((size_t)p & (G.pagesize - 1))
abort ();
}
/* We have a good page, might as well hold onto it... */
e = (struct page_entry *) xmalloc (sizeof (struct page_entry));
e->bytes = G.pagesize;
e->page = p;
e->next = main_zone.free_pages;
main_zone.free_pages = e;
}
#endif
}
/* Start a new GGC zone. */
struct alloc_zone *
new_ggc_zone (const char * name)
{
struct alloc_zone *new_zone = xcalloc (1, sizeof (struct alloc_zone));
new_zone->name = name;
new_zone->next_zone = G.zones->next_zone;
G.zones->next_zone = new_zone;
return new_zone;
}
/* Destroy a GGC zone. */
void
destroy_ggc_zone (struct alloc_zone * dead_zone)
{
struct alloc_zone *z;
for (z = G.zones; z && z->next_zone != dead_zone; z = z->next_zone)
/* Just find that zone. */ ;
/* We should have found the zone in the list. Anything else is
fatal.
If we did find the zone, we expect this zone to be empty.
A ggc_collect should have emptied it before we can destroy it. */
if (!z || dead_zone->allocated != 0)
abort ();
/* Unchain the dead zone, release all its pages and free it. */
z->next_zone = z->next_zone->next_zone;
release_pages (dead_zone);
free (dead_zone);
}
/* Increment the `GC context'. Objects allocated in an outer context
are never freed, eliminating the need to register their roots. */
void
ggc_push_context (void)
{
struct alloc_zone *zone;
for (zone = G.zones; zone; zone = zone->next_zone)
++(zone->context_depth);
/* Die on wrap. */
if (main_zone.context_depth >= HOST_BITS_PER_LONG)
abort ();
}
/* Decrement the `GC context'. All objects allocated since the
previous ggc_push_context are migrated to the outer context. */
static void
ggc_pop_context_1 (struct alloc_zone *zone)
{
unsigned long omask;
unsigned depth;
page_entry *p;
depth = --(zone->context_depth);
omask = (unsigned long)1 << (depth + 1);
if (!((zone->context_depth_allocations | zone->context_depth_collections) & omask))
return;
zone->context_depth_allocations |= (zone->context_depth_allocations & omask) >> 1;
zone->context_depth_allocations &= omask - 1;
zone->context_depth_collections &= omask - 1;
/* Any remaining pages in the popped context are lowered to the new
current context; i.e. objects allocated in the popped context and
left over are imported into the previous context. */
for (p = zone->pages; p != NULL; p = p->next)
if (p->context_depth > depth)
p->context_depth = depth;
}
/* Pop all the zone contexts. */
void
ggc_pop_context (void)
{
struct alloc_zone *zone;
for (zone = G.zones; zone; zone = zone->next_zone)
ggc_pop_context_1 (zone);
}
/* Poison the chunk. */
#ifdef ENABLE_GC_CHECKING
#define poison_chunk(CHUNK, SIZE) \
memset ((CHUNK)->u.data, 0xa5, (SIZE))
#else
#define poison_chunk(CHUNK, SIZE)
#endif
/* Free all empty pages and objects within a page for a given zone */
static void
sweep_pages (struct alloc_zone *zone)
{
page_entry **pp, *p, *next;
struct alloc_chunk *chunk, *last_free, *end;
size_t last_free_size, allocated = 0;
/* First, reset the free_chunks lists, since we are going to
re-free free chunks in hopes of coalescing them into large chunks. */
memset (zone->free_chunks, 0, sizeof (zone->free_chunks));
pp = &zone->pages;
for (p = zone->pages; p ; p = next)
{
next = p->next;
/* For empty pages, just free the page. */
if (p->bytes_free == G.pagesize && p->context_depth == zone->context_depth)
{
*pp = next;
#ifdef ENABLE_GC_CHECKING
/* Poison the page. */
memset (p->page, 0xb5, p->bytes);
#endif
free_page (p);
continue;
}
/* Large pages are all or none affairs. Either they are
completely empty, or they are completely full.
Thus, if the above didn't catch it, we need not do anything
except remove the mark and reset the bytes_free.
XXX: Should we bother to increment allocated. */
else if (p->large_p)
{
p->bytes_free = p->bytes;
((struct alloc_chunk *)p->page)->mark = 0;
continue;
}
pp = &p->next;
/* This page has now survived another collection. */
p->survived++;
/* Which leaves full and partial pages. Step through all chunks,
consolidate those that are free and insert them into the free
lists. Note that consolidation slows down collection
slightly. */
chunk = (struct alloc_chunk *)p->page;
end = (struct alloc_chunk *)(p->page + G.pagesize);
last_free = NULL;
last_free_size = 0;
do
{
prefetch ((struct alloc_chunk *)(chunk->u.data + chunk->size));
if (chunk->mark || p->context_depth < zone->context_depth)
{
if (last_free)
{
last_free->type = 0;
last_free->size = last_free_size;
last_free->mark = 0;
poison_chunk (last_free, last_free_size);
free_chunk (last_free, last_free_size, zone);
last_free = NULL;
}
if (chunk->mark)
{
allocated += chunk->size + CHUNK_OVERHEAD;
p->bytes_free += chunk->size + CHUNK_OVERHEAD;
}
chunk->mark = 0;
#ifdef ENABLE_CHECKING
if (p->bytes_free > p->bytes)
abort ();
#endif
}
else
{
if (last_free)
{
last_free_size += CHUNK_OVERHEAD + chunk->size;
}
else
{
last_free = chunk;
last_free_size = chunk->size;
}
}
chunk = (struct alloc_chunk *)(chunk->u.data + chunk->size);
}
while (chunk < end);
if (last_free)
{
last_free->type = 0;
last_free->size = last_free_size;
last_free->mark = 0;
poison_chunk (last_free, last_free_size);
free_chunk (last_free, last_free_size, zone);
}
}
zone->allocated = allocated;
}
/* mark-and-sweep routine for collecting a single zone. NEED_MARKING
is true if we need to mark before sweeping, false if some other
zone collection has already performed marking for us. Returns true
if we collected, false otherwise. */
static bool
ggc_collect_1 (struct alloc_zone *zone, bool need_marking)
{
/* Avoid frequent unnecessary work by skipping collection if the
total allocations haven't expanded much since the last
collection. */
float allocated_last_gc =
MAX (zone->allocated_last_gc, (size_t)PARAM_VALUE (GGC_MIN_HEAPSIZE) * 1024);
float min_expand = allocated_last_gc * PARAM_VALUE (GGC_MIN_EXPAND) / 100;
if (zone->allocated < allocated_last_gc + min_expand)
return false;
if (!quiet_flag)
fprintf (stderr, " {%s GC %luk -> ", zone->name, (unsigned long) zone->allocated / 1024);
/* Zero the total allocated bytes. This will be recalculated in the
sweep phase. */
zone->allocated = 0;
/* Release the pages we freed the last time we collected, but didn't
reuse in the interim. */
release_pages (zone);
/* Indicate that we've seen collections at this context depth. */
zone->context_depth_collections
= ((unsigned long)1 << (zone->context_depth + 1)) - 1;
if (need_marking)
ggc_mark_roots ();
sweep_pages (zone);
zone->was_collected = true;
zone->allocated_last_gc = zone->allocated;
if (!quiet_flag)
fprintf (stderr, "%luk}", (unsigned long) zone->allocated / 1024);
return true;
}
/* Calculate the average page survival rate in terms of number of
collections. */
static float
calculate_average_page_survival (struct alloc_zone *zone)
{
float count = 0.0;
float survival = 0.0;
page_entry *p;
for (p = zone->pages; p; p = p->next)
{
count += 1.0;
survival += p->survived;
}
return survival/count;
}
/* Check the magic cookies all of the chunks contain, to make sure we
aren't doing anything stupid, like stomping on alloc_chunk
structures. */
static inline void
check_cookies (void)
{
#ifdef COOKIE_CHECKING
page_entry *p;
struct alloc_zone *zone;
for (zone = G.zones; zone; zone = zone->next_zone)
{
for (p = zone->pages; p; p = p->next)
{
if (!p->large_p)
{
struct alloc_chunk *chunk = (struct alloc_chunk *)p->page;
struct alloc_chunk *end = (struct alloc_chunk *)(p->page + G.pagesize);
do
{
if (chunk->magic != CHUNK_MAGIC && chunk->magic != DEADCHUNK_MAGIC)
abort ();
chunk = (struct alloc_chunk *)(chunk->u.data + chunk->size);
}
while (chunk < end);
}
}
}
#endif
}
/* Top level collection routine. */
void
ggc_collect (void)
{
struct alloc_zone *zone;
bool marked = false;
float f;
timevar_push (TV_GC);
check_cookies ();
/* Start by possibly collecting the main zone. */
main_zone.was_collected = false;
marked |= ggc_collect_1 (&main_zone, true);
/* In order to keep the number of collections down, we don't
collect other zones unless we are collecting the main zone. This
gives us roughly the same number of collections as we used to
have with the old gc. The number of collection is important
because our main slowdown (according to profiling) is now in
marking. So if we mark twice as often as we used to, we'll be
twice as slow. Hopefully we'll avoid this cost when we mark
zone-at-a-time. */
if (main_zone.was_collected)
{
struct alloc_zone *zone;
for (zone = main_zone.next_zone; zone; zone = zone->next_zone)
{
check_cookies ();
zone->was_collected = false;
marked |= ggc_collect_1 (zone, !marked);
}
}
/* Print page survival stats, if someone wants them. */
if (GGC_DEBUG_LEVEL >= 2)
{
for (zone = G.zones; zone; zone = zone->next_zone)
{
if (zone->was_collected)
{
f = calculate_average_page_survival (zone);
printf ("Average page survival in zone `%s' is %f\n",
zone->name, f);
}
}
}
/* Since we don't mark zone at a time right now, marking in any
zone means marking in every zone. So we have to clear all the
marks in all the zones that weren't collected already. */
if (marked)
{
page_entry *p;
for (zone = G.zones; zone; zone = zone->next_zone)
{
if (zone->was_collected)
continue;
for (p = zone->pages; p; p = p->next)
{
if (!p->large_p)
{
struct alloc_chunk *chunk = (struct alloc_chunk *)p->page;
struct alloc_chunk *end = (struct alloc_chunk *)(p->page + G.pagesize);
do
{
prefetch ((struct alloc_chunk *)(chunk->u.data + chunk->size));
if (chunk->mark || p->context_depth < zone->context_depth)
{
if (chunk->mark)
p->bytes_free += chunk->size + CHUNK_OVERHEAD;
#ifdef ENABLE_CHECKING
if (p->bytes_free > p->bytes)
abort ();
#endif
chunk->mark = 0;
}
chunk = (struct alloc_chunk *)(chunk->u.data + chunk->size);
}
while (chunk < end);
}
else
{
p->bytes_free = p->bytes;
((struct alloc_chunk *)p->page)->mark = 0;
}
}
}
}
timevar_pop (TV_GC);
}
/* Print allocation statistics. */
void
ggc_print_statistics (void)
{
}
struct ggc_pch_data
{
struct ggc_pch_ondisk
{
unsigned total;
} d;
size_t base;
size_t written;
};
/* Initialize the PCH datastructure. */
struct ggc_pch_data *
init_ggc_pch (void)
{
return xcalloc (sizeof (struct ggc_pch_data), 1);
}
/* Add the size of object X to the size of the PCH data. */
void
ggc_pch_count_object (struct ggc_pch_data *d, void *x ATTRIBUTE_UNUSED,
size_t size, bool is_string)
{
if (!is_string)
{
d->d.total += size + CHUNK_OVERHEAD;
}
else
d->d.total += size;
}
/* Return the total size of the PCH data. */
size_t
ggc_pch_total_size (struct ggc_pch_data *d)
{
return d->d.total;
}
/* Set the base address for the objects in the PCH file. */
void
ggc_pch_this_base (struct ggc_pch_data *d, void *base)
{
d->base = (size_t) base;
}
/* Allocate a place for object X of size SIZE in the PCH file. */
char *
ggc_pch_alloc_object (struct ggc_pch_data *d, void *x,
size_t size, bool is_string)
{
char *result;
result = (char *)d->base;
if (!is_string)
{
struct alloc_chunk *chunk = (struct alloc_chunk *) ((char *)x - CHUNK_OVERHEAD);
if (chunk->size == LARGE_OBJECT_SIZE)
d->base += ggc_get_size (x) + CHUNK_OVERHEAD;
else
d->base += chunk->size + CHUNK_OVERHEAD;
return result + CHUNK_OVERHEAD;
}
else
{
d->base += size;
return result;
}
}
/* Prepare to write out the PCH data to file F. */
void
ggc_pch_prepare_write (struct ggc_pch_data *d ATTRIBUTE_UNUSED,
FILE *f ATTRIBUTE_UNUSED)
{
/* Nothing to do. */
}
/* Write out object X of SIZE to file F. */
void
ggc_pch_write_object (struct ggc_pch_data *d ATTRIBUTE_UNUSED,
FILE *f, void *x, void *newx ATTRIBUTE_UNUSED,
size_t size, bool is_string)
{
if (!is_string)
{
struct alloc_chunk *chunk = (struct alloc_chunk *) ((char *)x - CHUNK_OVERHEAD);
size = ggc_get_size (x);
if (fwrite (chunk, size + CHUNK_OVERHEAD, 1, f) != 1)
fatal_error ("can't write PCH file: %m");
d->written += size + CHUNK_OVERHEAD;
}
else
{
if (fwrite (x, size, 1, f) != 1)
fatal_error ("can't write PCH file: %m");
d->written += size;
}
if (d->written == d->d.total
&& fseek (f, ROUND_UP_VALUE (d->d.total, G.pagesize), SEEK_CUR) != 0)
fatal_error ("can't write PCH file: %m");
}
void
ggc_pch_finish (struct ggc_pch_data *d, FILE *f)
{
if (fwrite (&d->d, sizeof (d->d), 1, f) != 1)
fatal_error ("can't write PCH file: %m");
free (d);
}
void
ggc_pch_read (FILE *f, void *addr)
{
struct ggc_pch_ondisk d;
struct page_entry *entry;
char *pte;
if (fread (&d, sizeof (d), 1, f) != 1)
fatal_error ("can't read PCH file: %m");
entry = xcalloc (1, sizeof (struct page_entry));
entry->bytes = d.total;
entry->page = addr;
entry->context_depth = 0;
entry->zone = &main_zone;
for (pte = entry->page;
pte < entry->page + entry->bytes;
pte += G.pagesize)
set_page_table_entry (pte, entry);
}
|