summaryrefslogtreecommitdiffstats
path: root/js/src/gc/Sweeping.cpp
blob: f1827990ebb262831f99e72b6a82706dd6f90eba (plain)
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
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
2030
2031
2032
2033
2034
2035
2036
2037
2038
2039
2040
2041
2042
2043
2044
2045
2046
2047
2048
2049
2050
2051
2052
2053
2054
2055
2056
2057
2058
2059
2060
2061
2062
2063
2064
2065
2066
2067
2068
2069
2070
2071
2072
2073
2074
2075
2076
2077
2078
2079
2080
2081
2082
2083
2084
2085
2086
2087
2088
2089
2090
2091
2092
2093
2094
2095
2096
2097
2098
2099
2100
2101
2102
2103
2104
2105
2106
2107
2108
2109
2110
2111
2112
2113
2114
2115
2116
2117
2118
2119
2120
2121
2122
2123
2124
2125
2126
2127
2128
2129
2130
2131
2132
2133
2134
2135
2136
2137
2138
2139
2140
2141
2142
2143
2144
2145
2146
2147
2148
2149
2150
2151
2152
2153
2154
2155
2156
2157
2158
2159
2160
2161
2162
2163
2164
2165
2166
2167
2168
2169
2170
2171
2172
2173
2174
2175
2176
2177
2178
2179
2180
2181
2182
2183
2184
2185
2186
2187
2188
2189
2190
2191
2192
2193
2194
2195
2196
2197
2198
2199
2200
2201
2202
2203
2204
2205
2206
2207
2208
2209
2210
2211
2212
2213
2214
2215
2216
2217
2218
2219
2220
2221
2222
2223
2224
2225
2226
2227
2228
2229
2230
2231
2232
2233
2234
2235
2236
2237
2238
2239
2240
2241
2242
2243
2244
2245
2246
2247
2248
2249
2250
2251
2252
2253
2254
2255
2256
2257
2258
2259
2260
2261
2262
2263
2264
2265
2266
2267
2268
2269
2270
2271
2272
2273
2274
2275
2276
2277
2278
2279
2280
2281
2282
2283
2284
2285
2286
2287
2288
2289
2290
2291
2292
2293
2294
2295
2296
2297
2298
2299
2300
2301
2302
2303
2304
2305
2306
2307
2308
2309
2310
2311
2312
2313
2314
2315
2316
2317
2318
2319
2320
2321
2322
2323
2324
2325
2326
2327
2328
2329
2330
2331
2332
2333
2334
2335
2336
2337
2338
2339
2340
2341
2342
2343
2344
2345
2346
2347
2348
2349
2350
2351
2352
2353
2354
2355
2356
2357
2358
2359
2360
2361
2362
2363
2364
2365
2366
2367
2368
2369
2370
2371
2372
2373
2374
2375
2376
2377
2378
2379
2380
2381
2382
2383
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
 * vim: set ts=8 sts=2 et sw=2 tw=80:
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

/*
 * Implementation of GC sweeping.
 *
 * In the SpiderMonkey GC, 'sweeping' is used to mean two things:
 *  - updating data structures to remove pointers to dead GC things and updating
 *    pointers to moved GC things
 *  - finalizing dead GC things
 *
 * Furthermore, the GC carries out gray and weak marking after the start of the
 * sweep phase. This is also implemented in this file.
 */

#include "mozilla/Maybe.h"
#include "mozilla/ScopeExit.h"
#include "mozilla/TimeStamp.h"

#include "builtin/FinalizationRegistryObject.h"
#include "builtin/WeakRefObject.h"
#include "debugger/DebugAPI.h"
#include "gc/AllocKind.h"
#include "gc/FinalizationObservers.h"
#include "gc/GCInternals.h"
#include "gc/GCLock.h"
#include "gc/GCProbes.h"
#include "gc/GCRuntime.h"
#include "gc/ParallelWork.h"
#include "gc/Statistics.h"
#include "gc/TraceKind.h"
#include "gc/WeakMap.h"
#include "gc/Zone.h"
#include "jit/JitRuntime.h"
#include "jit/JitZone.h"
#include "proxy/DeadObjectProxy.h"
#include "vm/BigIntType.h"
#include "vm/HelperThreads.h"
#include "vm/JSContext.h"
#include "vm/Time.h"
#include "vm/WrapperObject.h"

#include "gc/PrivateIterators-inl.h"
#include "vm/GeckoProfiler-inl.h"
#include "vm/JSObject-inl.h"
#include "vm/PropMap-inl.h"
#include "vm/Shape-inl.h"
#include "vm/StringType-inl.h"

using namespace js;
using namespace js::gc;

using mozilla::TimeStamp;

struct js::gc::FinalizePhase {
  gcstats::PhaseKind statsPhase;
  AllocKinds kinds;
};

/*
 * Finalization order for objects swept incrementally on the main thread.
 */
static constexpr FinalizePhase ForegroundObjectFinalizePhase = {
    gcstats::PhaseKind::FINALIZE_OBJECT,
    {AllocKind::OBJECT0, AllocKind::OBJECT2, AllocKind::OBJECT4,
     AllocKind::OBJECT8, AllocKind::OBJECT12, AllocKind::OBJECT16}};

/*
 * Finalization order for GC things swept incrementally on the main thread.
 */
static constexpr FinalizePhase ForegroundNonObjectFinalizePhase = {
    gcstats::PhaseKind::FINALIZE_NON_OBJECT,
    {AllocKind::SCRIPT, AllocKind::JITCODE}};

/*
 * Finalization order for GC things swept on the background thread.
 */
static constexpr FinalizePhase BackgroundFinalizePhases[] = {
    {gcstats::PhaseKind::FINALIZE_OBJECT,
     {AllocKind::FUNCTION, AllocKind::FUNCTION_EXTENDED,
      AllocKind::OBJECT0_BACKGROUND, AllocKind::OBJECT2_BACKGROUND,
      AllocKind::ARRAYBUFFER4, AllocKind::OBJECT4_BACKGROUND,
      AllocKind::ARRAYBUFFER8, AllocKind::OBJECT8_BACKGROUND,
      AllocKind::ARRAYBUFFER12, AllocKind::OBJECT12_BACKGROUND,
      AllocKind::ARRAYBUFFER16, AllocKind::OBJECT16_BACKGROUND}},
    {gcstats::PhaseKind::FINALIZE_NON_OBJECT,
     {AllocKind::SCOPE, AllocKind::REGEXP_SHARED, AllocKind::FAT_INLINE_STRING,
      AllocKind::STRING, AllocKind::EXTERNAL_STRING, AllocKind::FAT_INLINE_ATOM,
      AllocKind::ATOM, AllocKind::SYMBOL, AllocKind::BIGINT, AllocKind::SHAPE,
      AllocKind::BASE_SHAPE, AllocKind::GETTER_SETTER,
      AllocKind::COMPACT_PROP_MAP, AllocKind::NORMAL_PROP_MAP,
      AllocKind::DICT_PROP_MAP}}};

template <typename T>
inline size_t Arena::finalize(JS::GCContext* gcx, AllocKind thingKind,
                              size_t thingSize) {
  /* Enforce requirements on size of T. */
  MOZ_ASSERT(thingSize % CellAlignBytes == 0);
  MOZ_ASSERT(thingSize >= MinCellSize);
  MOZ_ASSERT(thingSize <= 255);

  MOZ_ASSERT(allocated());
  MOZ_ASSERT(thingKind == getAllocKind());
  MOZ_ASSERT(thingSize == getThingSize());
  MOZ_ASSERT(!onDelayedMarkingList_);

  uint_fast16_t firstThing = firstThingOffset(thingKind);
  uint_fast16_t firstThingOrSuccessorOfLastMarkedThing = firstThing;
  uint_fast16_t lastThing = ArenaSize - thingSize;

  FreeSpan newListHead;
  FreeSpan* newListTail = &newListHead;
  size_t nmarked = 0, nfinalized = 0;

  for (ArenaCellIterUnderFinalize cell(this); !cell.done(); cell.next()) {
    T* t = cell.as<T>();
    if (TenuredThingIsMarkedAny(t)) {
      uint_fast16_t thing = uintptr_t(t) & ArenaMask;
      if (thing != firstThingOrSuccessorOfLastMarkedThing) {
        // We just finished passing over one or more free things,
        // so record a new FreeSpan.
        newListTail->initBounds(firstThingOrSuccessorOfLastMarkedThing,
                                thing - thingSize, this);
        newListTail = newListTail->nextSpanUnchecked(this);
      }
      firstThingOrSuccessorOfLastMarkedThing = thing + thingSize;
      nmarked++;
    } else {
      t->finalize(gcx);
      AlwaysPoison(t, JS_SWEPT_TENURED_PATTERN, thingSize,
                   MemCheckKind::MakeUndefined);
      gcprobes::TenuredFinalize(t);
      nfinalized++;
    }
  }

  if constexpr (std::is_same_v<T, JSObject>) {
    if (isNewlyCreated_) {
      zone->pretenuring.updateCellCountsInNewlyCreatedArenas(
          nmarked + nfinalized, nmarked);
    }
  }
  isNewlyCreated_ = 0;

  if (thingKind == AllocKind::STRING ||
      thingKind == AllocKind::FAT_INLINE_STRING) {
    zone->markedStrings += nmarked;
    zone->finalizedStrings += nfinalized;
  }

  if (nmarked == 0) {
    // Do nothing. The caller will update the arena appropriately.
    MOZ_ASSERT(newListTail == &newListHead);
    DebugOnlyPoison(data, JS_SWEPT_TENURED_PATTERN, sizeof(data),
                    MemCheckKind::MakeUndefined);
    return nmarked;
  }

  MOZ_ASSERT(firstThingOrSuccessorOfLastMarkedThing != firstThing);
  uint_fast16_t lastMarkedThing =
      firstThingOrSuccessorOfLastMarkedThing - thingSize;
  if (lastThing == lastMarkedThing) {
    // If the last thing was marked, we will have already set the bounds of
    // the final span, and we just need to terminate the list.
    newListTail->initAsEmpty();
  } else {
    // Otherwise, end the list with a span that covers the final stretch of free
    // things.
    newListTail->initFinal(firstThingOrSuccessorOfLastMarkedThing, lastThing,
                           this);
  }

  firstFreeSpan = newListHead;
#ifdef DEBUG
  size_t nfree = numFreeThings(thingSize);
  MOZ_ASSERT(nfree + nmarked == thingsPerArena(thingKind));
#endif
  return nmarked;
}

// Finalize arenas from src list, releasing empty arenas if keepArenas wasn't
// specified and inserting the others into the appropriate destination size
// bins.
template <typename T>
static inline bool FinalizeTypedArenas(JS::GCContext* gcx, ArenaList& src,
                                       SortedArenaList& dest,
                                       AllocKind thingKind,
                                       SliceBudget& budget) {
  MOZ_ASSERT(gcx->isFinalizing());

  size_t thingSize = Arena::thingSize(thingKind);
  size_t thingsPerArena = Arena::thingsPerArena(thingKind);
  size_t markCount = 0;

  auto updateMarkCount = mozilla::MakeScopeExit([&] {
    GCRuntime* gc = &gcx->runtimeFromAnyThread()->gc;
    gc->stats().addCount(gcstats::COUNT_CELLS_MARKED, markCount);
  });

  while (Arena* arena = src.takeFirstArena()) {
    size_t nmarked = arena->finalize<T>(gcx, thingKind, thingSize);
    size_t nfree = thingsPerArena - nmarked;

    markCount += nmarked;

    if (nmarked) {
      dest.insertAt(arena, nfree);
    } else {
      arena->chunk()->recycleArena(arena, dest, thingsPerArena);
    }

    budget.step(thingsPerArena);
    if (budget.isOverBudget()) {
      return false;
    }
  }

  return true;
}

/*
 * Finalize the list of areans.
 */
static bool FinalizeArenas(JS::GCContext* gcx, ArenaList& src,
                           SortedArenaList& dest, AllocKind thingKind,
                           SliceBudget& budget) {
  switch (thingKind) {
#define EXPAND_CASE(allocKind, traceKind, type, sizedType, bgFinal, nursery, \
                    compact)                                                 \
  case AllocKind::allocKind:                                                 \
    return FinalizeTypedArenas<type>(gcx, src, dest, thingKind, budget);
    FOR_EACH_ALLOCKIND(EXPAND_CASE)
#undef EXPAND_CASE

    default:
      MOZ_CRASH("Invalid alloc kind");
  }
}

void GCRuntime::initBackgroundSweep(Zone* zone, JS::GCContext* gcx,
                                    const FinalizePhase& phase) {
  gcstats::AutoPhase ap(stats(), phase.statsPhase);
  for (auto kind : phase.kinds) {
    zone->arenas.initBackgroundSweep(kind);
  }
}

void ArenaLists::initBackgroundSweep(AllocKind thingKind) {
  MOZ_ASSERT(IsBackgroundFinalized(thingKind));
  MOZ_ASSERT(concurrentUse(thingKind) == ConcurrentUse::None);

  if (!collectingArenaList(thingKind).isEmpty()) {
    concurrentUse(thingKind) = ConcurrentUse::BackgroundFinalize;
  }
}

void GCRuntime::backgroundFinalize(JS::GCContext* gcx, Zone* zone,
                                   AllocKind kind, Arena** empty) {
  MOZ_ASSERT(empty);

  ArenaLists* lists = &zone->arenas;
  ArenaList& arenas = lists->collectingArenaList(kind);
  if (arenas.isEmpty()) {
    MOZ_ASSERT(lists->concurrentUse(kind) == ArenaLists::ConcurrentUse::None);
    return;
  }

  SortedArenaList finalizedSorted(Arena::thingsPerArena(kind));

  auto unlimited = SliceBudget::unlimited();
  FinalizeArenas(gcx, arenas, finalizedSorted, kind, unlimited);
  MOZ_ASSERT(arenas.isEmpty());

  finalizedSorted.extractEmpty(empty);

  // When marking begins, all arenas are moved from arenaLists to
  // collectingArenaLists. When the mutator runs, new arenas are allocated in
  // arenaLists. Now that finalization is complete, we want to merge these lists
  // back together.

  // We must take the GC lock to be able to safely modify the ArenaList;
  // however, this does not by itself make the changes visible to all threads,
  // as not all threads take the GC lock to read the ArenaLists.
  // That safety is provided by the ReleaseAcquire memory ordering of the
  // background finalize state, which we explicitly set as the final step.
  {
    AutoLockGC lock(rt);
    MOZ_ASSERT(lists->concurrentUse(kind) ==
               ArenaLists::ConcurrentUse::BackgroundFinalize);
    lists->mergeFinalizedArenas(kind, finalizedSorted);
  }

  lists->concurrentUse(kind) = ArenaLists::ConcurrentUse::None;
}

// After finalizing arenas, merge the following to get the final state of an
// arena list:
//  - arenas allocated during marking
//  - arenas allocated during sweeping
//  - finalized arenas
void ArenaLists::mergeFinalizedArenas(AllocKind kind,
                                      SortedArenaList& finalizedArenas) {
#ifdef DEBUG
  // Updating arena lists off-thread requires taking the GC lock because the
  // main thread uses these when allocating.
  if (IsBackgroundFinalized(kind)) {
    runtimeFromAnyThread()->gc.assertCurrentThreadHasLockedGC();
  }
#endif

  ArenaList& arenas = arenaList(kind);

  ArenaList allocatedDuringCollection = std::move(arenas);
  arenas = finalizedArenas.toArenaList();
  arenas.insertListWithCursorAtEnd(allocatedDuringCollection);

  collectingArenaList(kind).clear();
}

void ArenaLists::queueForegroundThingsForSweep() {
  gcCompactPropMapArenasToUpdate =
      collectingArenaList(AllocKind::COMPACT_PROP_MAP).head();
  gcNormalPropMapArenasToUpdate =
      collectingArenaList(AllocKind::NORMAL_PROP_MAP).head();
}

void GCRuntime::sweepBackgroundThings(ZoneList& zones) {
  if (zones.isEmpty()) {
    return;
  }

  JS::GCContext* gcx = TlsGCContext.get();
  MOZ_ASSERT(gcx->isFinalizing());

  // Sweep zones in order. The atoms zone must be finalized last as other
  // zones may have direct pointers into it.
  while (!zones.isEmpty()) {
    Zone* zone = zones.removeFront();
    MOZ_ASSERT(zone->isGCFinished());

    TimeStamp startTime = TimeStamp::Now();

    Arena* emptyArenas = zone->arenas.takeSweptEmptyArenas();

    // We must finalize thing kinds in the order specified by
    // BackgroundFinalizePhases.
    for (auto phase : BackgroundFinalizePhases) {
      for (auto kind : phase.kinds) {
        backgroundFinalize(gcx, zone, kind, &emptyArenas);
      }
    }

    // Release any arenas that are now empty.
    //
    // Empty arenas are only released after everything has been finalized so
    // that it's still possible to get a thing's zone after the thing has been
    // finalized. The HeapPtr destructor depends on this, and this allows
    // HeapPtrs between things of different alloc kind regardless of
    // finalization order.
    //
    // Periodically drop and reaquire the GC lock every so often to avoid
    // blocking the main thread from allocating chunks.
    static const size_t LockReleasePeriod = 32;

    while (emptyArenas) {
      AutoLockGC lock(this);
      for (size_t i = 0; i < LockReleasePeriod && emptyArenas; i++) {
        Arena* arena = emptyArenas;
        emptyArenas = emptyArenas->next;
        releaseArena(arena, lock);
      }
    }

    // Record time spent sweeping this zone.
    TimeStamp endTime = TimeStamp::Now();
    zone->perZoneGCTime += endTime - startTime;
  }
}

void GCRuntime::assertBackgroundSweepingFinished() {
#ifdef DEBUG
  {
    AutoLockHelperThreadState lock;
    MOZ_ASSERT(backgroundSweepZones.ref().isEmpty());
  }

  for (ZonesIter zone(this, WithAtoms); !zone.done(); zone.next()) {
    for (auto kind : AllAllocKinds()) {
      MOZ_ASSERT_IF(state() != State::Prepare && state() != State::Mark &&
                        state() != State::Sweep,
                    zone->arenas.collectingArenaList(kind).isEmpty());
      MOZ_ASSERT(zone->arenas.doneBackgroundFinalize(kind));
    }
  }
#endif
}

void GCRuntime::queueZonesAndStartBackgroundSweep(ZoneList&& zones) {
  {
    AutoLockHelperThreadState lock;
    MOZ_ASSERT(!requestSliceAfterBackgroundTask);
    backgroundSweepZones.ref().appendList(std::move(zones));
    if (useBackgroundThreads) {
      sweepTask.startOrRunIfIdle(lock);
    }
  }
  if (!useBackgroundThreads) {
    sweepTask.join();
    sweepTask.runFromMainThread();
  }
}

BackgroundSweepTask::BackgroundSweepTask(GCRuntime* gc)
    : GCParallelTask(gc, gcstats::PhaseKind::SWEEP, GCUse::Finalizing) {}

void BackgroundSweepTask::run(AutoLockHelperThreadState& lock) {
  gc->sweepFromBackgroundThread(lock);
}

void GCRuntime::sweepFromBackgroundThread(AutoLockHelperThreadState& lock) {
  do {
    ZoneList zones;
    zones.appendList(std::move(backgroundSweepZones.ref()));

    AutoUnlockHelperThreadState unlock(lock);
    sweepBackgroundThings(zones);

    // The main thread may call queueZonesAndStartBackgroundSweep() while this
    // is running so we must check there is no more work after releasing the
    // lock.
  } while (!backgroundSweepZones.ref().isEmpty());

  maybeRequestGCAfterBackgroundTask(lock);
}

void GCRuntime::waitBackgroundSweepEnd() {
  sweepTask.join();
  if (state() != State::Sweep) {
    assertBackgroundSweepingFinished();
  }
}

void GCRuntime::startBackgroundFree() {
  AutoLockHelperThreadState lock;
  freeTask.startOrRunIfIdle(lock);
}

BackgroundFreeTask::BackgroundFreeTask(GCRuntime* gc)
    : GCParallelTask(gc, gcstats::PhaseKind::NONE) {
  // This can occur outside GCs so doesn't have a stats phase.
}

void BackgroundFreeTask::run(AutoLockHelperThreadState& lock) {
  gc->freeFromBackgroundThread(lock);
}

void GCRuntime::freeFromBackgroundThread(AutoLockHelperThreadState& lock) {
  do {
    LifoAlloc lifoBlocks(JSContext::TEMP_LIFO_ALLOC_PRIMARY_CHUNK_SIZE);
    lifoBlocks.transferFrom(&lifoBlocksToFree.ref());

    Nursery::BufferSet buffers;
    std::swap(buffers, buffersToFreeAfterMinorGC.ref());

    AutoUnlockHelperThreadState unlock(lock);

    lifoBlocks.freeAll();

    JS::GCContext* gcx = TlsGCContext.get();
    for (Nursery::BufferSet::Range r = buffers.all(); !r.empty();
         r.popFront()) {
      // Malloc memory associated with nursery objects is not tracked as these
      // are assumed to be short lived.
      gcx->freeUntracked(r.front());
    }
  } while (!lifoBlocksToFree.ref().isEmpty() ||
           !buffersToFreeAfterMinorGC.ref().empty());
}

void GCRuntime::waitBackgroundFreeEnd() { freeTask.join(); }

template <class ZoneIterT>
IncrementalProgress GCRuntime::markWeakReferences(
    SliceBudget& incrementalBudget) {
  MOZ_ASSERT(!marker().isWeakMarking());

  gcstats::AutoPhase ap1(stats(), gcstats::PhaseKind::SWEEP_MARK_WEAK);

  auto unlimited = SliceBudget::unlimited();
  SliceBudget& budget =
      marker().incrementalWeakMapMarkingEnabled ? incrementalBudget : unlimited;

  // Ensure we don't return to the mutator while we're still in weak marking
  // mode.
  auto leaveOnExit =
      mozilla::MakeScopeExit([&] { marker().leaveWeakMarkingMode(); });

  if (marker().enterWeakMarkingMode()) {
    // If there was an 'enter-weak-marking-mode' token in the queue, then it
    // and everything after it will still be in the queue so we can process
    // them now.
    while (processTestMarkQueue() == QueueYielded) {
    };

    // Do not rely on the information about not-yet-marked weak keys that have
    // been collected by barriers. Clear out the gcEphemeronEdges entries and
    // rebuild the full table. Note that this a cross-zone operation; delegate
    // zone entries will be populated by map zone traversals, so everything
    // needs to be cleared first, then populated.
    if (!marker().incrementalWeakMapMarkingEnabled) {
      for (ZoneIterT zone(this); !zone.done(); zone.next()) {
        AutoEnterOOMUnsafeRegion oomUnsafe;
        if (!zone->gcEphemeronEdges().clear()) {
          oomUnsafe.crash("clearing weak keys when entering weak marking mode");
        }
      }
    }

    for (ZoneIterT zone(this); !zone.done(); zone.next()) {
      if (zone->enterWeakMarkingMode(&marker(), budget) == NotFinished) {
        return NotFinished;
      }
    }
  }

  bool markedAny = true;
  while (markedAny) {
    if (!marker().markUntilBudgetExhausted(budget)) {
      MOZ_ASSERT(marker().incrementalWeakMapMarkingEnabled);
      return NotFinished;
    }

    markedAny = false;

    if (!marker().isWeakMarking()) {
      for (ZoneIterT zone(this); !zone.done(); zone.next()) {
        markedAny |= WeakMapBase::markZoneIteratively(zone, &marker());
      }
    }

    markedAny |= jit::JitRuntime::MarkJitcodeGlobalTableIteratively(&marker());
  }

  assertNoMarkingWork();

  return Finished;
}

IncrementalProgress GCRuntime::markWeakReferencesInCurrentGroup(
    SliceBudget& budget) {
  return markWeakReferences<SweepGroupZonesIter>(budget);
}

template <class ZoneIterT>
IncrementalProgress GCRuntime::markGrayRoots(SliceBudget& budget,
                                             gcstats::PhaseKind phase) {
  MOZ_ASSERT(marker().markColor() == MarkColor::Gray);

  gcstats::AutoPhase ap(stats(), phase);

  AutoUpdateLiveCompartments updateLive(this);
  marker().setRootMarkingMode(true);
  auto guard =
      mozilla::MakeScopeExit([this]() { marker().setRootMarkingMode(false); });

  IncrementalProgress result =
      traceEmbeddingGrayRoots(marker().tracer(), budget);
  if (result == NotFinished) {
    return NotFinished;
  }

  Compartment::traceIncomingCrossCompartmentEdgesForZoneGC(
      marker().tracer(), Compartment::GrayEdges);

  return Finished;
}

IncrementalProgress GCRuntime::markAllWeakReferences() {
  SliceBudget budget = SliceBudget::unlimited();
  return markWeakReferences<GCZonesIter>(budget);
}

void GCRuntime::markAllGrayReferences(gcstats::PhaseKind phase) {
  SliceBudget budget = SliceBudget::unlimited();
  markGrayRoots<GCZonesIter>(budget, phase);
  drainMarkStack();
}

void GCRuntime::dropStringWrappers() {
  /*
   * String "wrappers" are dropped on GC because their presence would require
   * us to sweep the wrappers in all compartments every time we sweep a
   * compartment group.
   */
  for (ZonesIter zone(this, WithAtoms); !zone.done(); zone.next()) {
    zone->dropStringWrappersOnGC();
  }
}

/*
 * Group zones that must be swept at the same time.
 *
 * From the point of view of the mutator, groups of zones transition atomically
 * from marking to sweeping. If compartment A has an edge to an unmarked object
 * in compartment B, then we must not start sweeping A in a later slice than we
 * start sweeping B. That's because a write barrier in A could lead to the
 * unmarked object in B becoming marked. However, if we had already swept that
 * object, we would be in trouble.
 *
 * If we consider these dependencies as a graph, then all the compartments in
 * any strongly-connected component of this graph must start sweeping in the
 * same slice.
 *
 * Tarjan's algorithm is used to calculate the components.
 */

bool Compartment::findSweepGroupEdges() {
  Zone* source = zone();
  for (WrappedObjectCompartmentEnum e(this); !e.empty(); e.popFront()) {
    Compartment* targetComp = e.front();
    Zone* target = targetComp->zone();

    if (!target->isGCMarking() || source->hasSweepGroupEdgeTo(target)) {
      continue;
    }

    for (ObjectWrapperEnum e(this, targetComp); !e.empty(); e.popFront()) {
      JSObject* key = e.front().mutableKey();
      MOZ_ASSERT(key->zone() == target);

      // Add an edge to the wrapped object's zone to ensure that the wrapper
      // zone is not still being marked when we start sweeping the wrapped zone.
      // As an optimization, if the wrapped object is already marked black there
      // is no danger of later marking and we can skip this.
      if (key->isMarkedBlack()) {
        continue;
      }

      if (!source->addSweepGroupEdgeTo(target)) {
        return false;
      }

      // We don't need to consider any more wrappers for this target
      // compartment since we already added an edge.
      break;
    }
  }

  return true;
}

bool Zone::findSweepGroupEdges(Zone* atomsZone) {
  MOZ_ASSERT_IF(this != atomsZone, !isAtomsZone());

#ifdef DEBUG
  if (FinalizationObservers* observers = finalizationObservers()) {
    observers->checkTables();
  }
#endif

  // Any zone may have a pointer to an atom in the atoms zone, and these aren't
  // in the cross compartment map.
  if (atomsZone->wasGCStarted() && !addSweepGroupEdgeTo(atomsZone)) {
    return false;
  }

  for (CompartmentsInZoneIter comp(this); !comp.done(); comp.next()) {
    if (!comp->findSweepGroupEdges()) {
      return false;
    }
  }

  return WeakMapBase::findSweepGroupEdgesForZone(this);
}

bool GCRuntime::addEdgesForMarkQueue() {
#ifdef DEBUG
  // For testing only.
  //
  // Add edges between all objects mentioned in the test mark queue, since
  // otherwise they will get marked in a different order than their sweep
  // groups. Note that this is only done at the beginning of an incremental
  // collection, so it is possible for objects to be added later that do not
  // follow the sweep group ordering. These objects will wait until their sweep
  // group comes up, or will be skipped if their sweep group is already past.
  JS::Zone* prevZone = nullptr;
  for (size_t i = 0; i < testMarkQueue.length(); i++) {
    Value val = testMarkQueue[i].get();
    if (!val.isObject()) {
      continue;
    }
    JSObject* obj = &val.toObject();
    JS::Zone* zone = obj->zone();
    if (!zone->isGCMarking()) {
      continue;
    }
    if (prevZone && prevZone != zone) {
      if (!prevZone->addSweepGroupEdgeTo(zone)) {
        return false;
      }
    }
    prevZone = zone;
  }
#endif
  return true;
}

bool GCRuntime::findSweepGroupEdges() {
  for (GCZonesIter zone(this); !zone.done(); zone.next()) {
    if (!zone->findSweepGroupEdges(atomsZone())) {
      return false;
    }
  }

  if (!addEdgesForMarkQueue()) {
    return false;
  }

  return DebugAPI::findSweepGroupEdges(rt);
}

void GCRuntime::groupZonesForSweeping(JS::GCReason reason) {
#ifdef DEBUG
  for (ZonesIter zone(this, WithAtoms); !zone.done(); zone.next()) {
    MOZ_ASSERT(zone->gcSweepGroupEdges().empty());
  }
#endif

  JSContext* cx = rt->mainContextFromOwnThread();
  ZoneComponentFinder finder(cx);
  if (!isIncremental || !findSweepGroupEdges()) {
    finder.useOneComponent();
  }

  // Use one component for two-slice zeal modes.
  if (useZeal && hasIncrementalTwoSliceZealMode()) {
    finder.useOneComponent();
  }

  for (GCZonesIter zone(this); !zone.done(); zone.next()) {
    MOZ_ASSERT(zone->isGCMarking());
    finder.addNode(zone);
  }
  sweepGroups = finder.getResultsList();
  currentSweepGroup = sweepGroups;
  sweepGroupIndex = 1;

  for (GCZonesIter zone(this); !zone.done(); zone.next()) {
    zone->clearSweepGroupEdges();
  }

#ifdef DEBUG
  unsigned idx = sweepGroupIndex;
  for (Zone* head = currentSweepGroup; head; head = head->nextGroup()) {
    for (Zone* zone = head; zone; zone = zone->nextNodeInGroup()) {
      MOZ_ASSERT(zone->isGCMarking());
      zone->gcSweepGroupIndex = idx;
    }
    idx++;
  }

  MOZ_ASSERT_IF(!isIncremental, !currentSweepGroup->nextGroup());
  for (ZonesIter zone(this, WithAtoms); !zone.done(); zone.next()) {
    MOZ_ASSERT(zone->gcSweepGroupEdges().empty());
  }
#endif
}

void GCRuntime::getNextSweepGroup() {
  currentSweepGroup = currentSweepGroup->nextGroup();
  ++sweepGroupIndex;
  if (!currentSweepGroup) {
    abortSweepAfterCurrentGroup = false;
    return;
  }

  MOZ_ASSERT_IF(abortSweepAfterCurrentGroup, !isIncremental);
  if (!isIncremental) {
    ZoneComponentFinder::mergeGroups(currentSweepGroup);
  }

  for (Zone* zone = currentSweepGroup; zone; zone = zone->nextNodeInGroup()) {
    MOZ_ASSERT(zone->gcState() == zone->initialMarkingState());
    MOZ_ASSERT(!zone->isQueuedForBackgroundSweep());
  }

  if (abortSweepAfterCurrentGroup) {
    markTask.join();

    // Abort collection of subsequent sweep groups.
    for (SweepGroupZonesIter zone(this); !zone.done(); zone.next()) {
      MOZ_ASSERT(!zone->gcNextGraphComponent);
      zone->changeGCState(zone->initialMarkingState(), Zone::NoGC);
      zone->arenas.unmarkPreMarkedFreeCells();
      zone->arenas.mergeArenasFromCollectingLists();
      zone->clearGCSliceThresholds();
    }

    for (SweepGroupCompartmentsIter comp(rt); !comp.done(); comp.next()) {
      resetGrayList(comp);
    }

    abortSweepAfterCurrentGroup = false;
    currentSweepGroup = nullptr;
  }
}

/*
 * Gray marking:
 *
 * At the end of collection, anything reachable from a gray root that has not
 * otherwise been marked black must be marked gray.
 *
 * This means that when marking things gray we must not allow marking to leave
 * the current compartment group, as that could result in things being marked
 * gray when they might subsequently be marked black.  To achieve this, when we
 * find a cross compartment pointer we don't mark the referent but add it to a
 * singly-linked list of incoming gray pointers that is stored with each
 * compartment.
 *
 * The list head is stored in Compartment::gcIncomingGrayPointers and contains
 * cross compartment wrapper objects. The next pointer is stored in the second
 * extra slot of the cross compartment wrapper.
 *
 * The list is created during gray marking when one of the
 * MarkCrossCompartmentXXX functions is called for a pointer that leaves the
 * current compartent group.  This calls DelayCrossCompartmentGrayMarking to
 * push the referring object onto the list.
 *
 * The list is traversed and then unlinked in
 * GCRuntime::markIncomingGrayCrossCompartmentPointers.
 */

static bool IsGrayListObject(JSObject* obj) {
  MOZ_ASSERT(obj);
  return obj->is<CrossCompartmentWrapperObject>() && !IsDeadProxyObject(obj);
}

/* static */
unsigned ProxyObject::grayLinkReservedSlot(JSObject* obj) {
  MOZ_ASSERT(IsGrayListObject(obj));
  return CrossCompartmentWrapperObject::GrayLinkReservedSlot;
}

#ifdef DEBUG
static void AssertNotOnGrayList(JSObject* obj) {
  MOZ_ASSERT_IF(
      IsGrayListObject(obj),
      GetProxyReservedSlot(obj, ProxyObject::grayLinkReservedSlot(obj))
          .isUndefined());
}
#endif

static void AssertNoWrappersInGrayList(JSRuntime* rt) {
#ifdef DEBUG
  for (CompartmentsIter c(rt); !c.done(); c.next()) {
    MOZ_ASSERT(!c->gcIncomingGrayPointers);
    for (Compartment::ObjectWrapperEnum e(c); !e.empty(); e.popFront()) {
      AssertNotOnGrayList(e.front().value().unbarrieredGet());
    }
  }
#endif
}

static JSObject* CrossCompartmentPointerReferent(JSObject* obj) {
  MOZ_ASSERT(IsGrayListObject(obj));
  return &obj->as<ProxyObject>().private_().toObject();
}

static JSObject* NextIncomingCrossCompartmentPointer(JSObject* prev,
                                                     bool unlink) {
  unsigned slot = ProxyObject::grayLinkReservedSlot(prev);
  JSObject* next = GetProxyReservedSlot(prev, slot).toObjectOrNull();
  MOZ_ASSERT_IF(next, IsGrayListObject(next));

  if (unlink) {
    SetProxyReservedSlot(prev, slot, UndefinedValue());
  }

  return next;
}

void js::gc::DelayCrossCompartmentGrayMarking(GCMarker* maybeMarker,
                                              JSObject* src) {
  MOZ_ASSERT_IF(!maybeMarker, !JS::RuntimeHeapIsBusy());
  MOZ_ASSERT(IsGrayListObject(src));
  MOZ_ASSERT(src->isMarkedGray());

  AutoTouchingGrayThings tgt;

  mozilla::Maybe<AutoLockGC> lock;
  if (maybeMarker && maybeMarker->isParallelMarking()) {
    // Synchronize access to JSCompartment::gcIncomingGrayPointers.
    //
    // TODO: Instead of building this list we could scan all incoming CCWs and
    // mark through gray ones when marking gray roots for a sweep group.
    lock.emplace(maybeMarker->runtime());
  }

  /* Called from MarkCrossCompartmentXXX functions. */
  unsigned slot = ProxyObject::grayLinkReservedSlot(src);
  JSObject* dest = CrossCompartmentPointerReferent(src);
  Compartment* comp = dest->compartment();

  if (GetProxyReservedSlot(src, slot).isUndefined()) {
    SetProxyReservedSlot(src, slot,
                         ObjectOrNullValue(comp->gcIncomingGrayPointers));
    comp->gcIncomingGrayPointers = src;
  } else {
    MOZ_ASSERT(GetProxyReservedSlot(src, slot).isObjectOrNull());
  }

#ifdef DEBUG
  /*
   * Assert that the object is in our list, also walking the list to check its
   * integrity.
   */
  JSObject* obj = comp->gcIncomingGrayPointers;
  bool found = false;
  while (obj) {
    if (obj == src) {
      found = true;
    }
    obj = NextIncomingCrossCompartmentPointer(obj, false);
  }
  MOZ_ASSERT(found);
#endif
}

void GCRuntime::markIncomingGrayCrossCompartmentPointers() {
  gcstats::AutoPhase ap(stats(), gcstats::PhaseKind::SWEEP_MARK_INCOMING_GRAY);

  for (SweepGroupCompartmentsIter c(rt); !c.done(); c.next()) {
    MOZ_ASSERT(c->zone()->isGCMarkingBlackAndGray());
    MOZ_ASSERT_IF(c->gcIncomingGrayPointers,
                  IsGrayListObject(c->gcIncomingGrayPointers));

    for (JSObject* src = c->gcIncomingGrayPointers; src;
         src = NextIncomingCrossCompartmentPointer(src, true)) {
      JSObject* dst = CrossCompartmentPointerReferent(src);
      MOZ_ASSERT(dst->compartment() == c);
      MOZ_ASSERT_IF(src->asTenured().isMarkedBlack(),
                    dst->asTenured().isMarkedBlack());

      if (src->asTenured().isMarkedGray()) {
        TraceManuallyBarrieredEdge(marker().tracer(), &dst,
                                   "cross-compartment gray pointer");
      }
    }

    c->gcIncomingGrayPointers = nullptr;
  }
}

static bool RemoveFromGrayList(JSObject* wrapper) {
  AutoTouchingGrayThings tgt;

  if (!IsGrayListObject(wrapper)) {
    return false;
  }

  unsigned slot = ProxyObject::grayLinkReservedSlot(wrapper);
  if (GetProxyReservedSlot(wrapper, slot).isUndefined()) {
    return false; /* Not on our list. */
  }

  JSObject* tail = GetProxyReservedSlot(wrapper, slot).toObjectOrNull();
  SetProxyReservedSlot(wrapper, slot, UndefinedValue());

  Compartment* comp = CrossCompartmentPointerReferent(wrapper)->compartment();
  JSObject* obj = comp->gcIncomingGrayPointers;
  if (obj == wrapper) {
    comp->gcIncomingGrayPointers = tail;
    return true;
  }

  while (obj) {
    unsigned slot = ProxyObject::grayLinkReservedSlot(obj);
    JSObject* next = GetProxyReservedSlot(obj, slot).toObjectOrNull();
    if (next == wrapper) {
      js::detail::SetProxyReservedSlotUnchecked(obj, slot,
                                                ObjectOrNullValue(tail));
      return true;
    }
    obj = next;
  }

  MOZ_CRASH("object not found in gray link list");
}

void GCRuntime::resetGrayList(Compartment* comp) {
  JSObject* src = comp->gcIncomingGrayPointers;
  while (src) {
    src = NextIncomingCrossCompartmentPointer(src, true);
  }
  comp->gcIncomingGrayPointers = nullptr;
}

#ifdef DEBUG
static bool HasIncomingCrossCompartmentPointers(JSRuntime* rt) {
  for (SweepGroupCompartmentsIter c(rt); !c.done(); c.next()) {
    if (c->gcIncomingGrayPointers) {
      return true;
    }
  }

  return false;
}
#endif

void js::NotifyGCNukeWrapper(JSContext* cx, JSObject* wrapper) {
  MOZ_ASSERT(IsCrossCompartmentWrapper(wrapper));

  /*
   * References to target of wrapper are being removed, we no longer have to
   * remember to mark it.
   */
  RemoveFromGrayList(wrapper);

  /*
   * Clean up WeakRef maps which might include this wrapper.
   */
  JSObject* target = UncheckedUnwrapWithoutExpose(wrapper);
  if (target->is<WeakRefObject>()) {
    WeakRefObject* weakRef = &target->as<WeakRefObject>();
    if (weakRef->target()) {
      cx->runtime()->gc.nukeWeakRefWrapper(wrapper, weakRef);
    }
  }

  /*
   * Clean up FinalizationRecord record objects which might be the target of
   * this wrapper.
   */
  if (target->is<FinalizationRecordObject>()) {
    auto* record = &target->as<FinalizationRecordObject>();
    cx->runtime()->gc.nukeFinalizationRecordWrapper(wrapper, record);
  }
}

enum {
  JS_GC_SWAP_OBJECT_A_REMOVED = 1 << 0,
  JS_GC_SWAP_OBJECT_B_REMOVED = 1 << 1
};

unsigned js::NotifyGCPreSwap(JSObject* a, JSObject* b) {
  /*
   * Two objects in the same compartment are about to have had their contents
   * swapped.  If either of them are in our gray pointer list, then we remove
   * them from the lists, returning a bitset indicating what happened.
   */
  return (RemoveFromGrayList(a) ? JS_GC_SWAP_OBJECT_A_REMOVED : 0) |
         (RemoveFromGrayList(b) ? JS_GC_SWAP_OBJECT_B_REMOVED : 0);
}

void js::NotifyGCPostSwap(JSObject* a, JSObject* b, unsigned removedFlags) {
  /*
   * Two objects in the same compartment have had their contents swapped.  If
   * either of them were in our gray pointer list, we re-add them again.
   */
  if (removedFlags & JS_GC_SWAP_OBJECT_A_REMOVED) {
    DelayCrossCompartmentGrayMarking(nullptr, b);
  }
  if (removedFlags & JS_GC_SWAP_OBJECT_B_REMOVED) {
    DelayCrossCompartmentGrayMarking(nullptr, a);
  }
}

static inline void MaybeCheckWeakMapMarking(GCRuntime* gc) {
#if defined(JS_GC_ZEAL) || defined(DEBUG)

  bool shouldCheck;
#  if defined(DEBUG)
  shouldCheck = true;
#  else
  shouldCheck = gc->hasZealMode(ZealMode::CheckWeakMapMarking);
#  endif

  if (shouldCheck) {
    for (SweepGroupZonesIter zone(gc); !zone.done(); zone.next()) {
      MOZ_RELEASE_ASSERT(WeakMapBase::checkMarkingForZone(zone));
    }
  }

#endif
}

IncrementalProgress GCRuntime::beginMarkingSweepGroup(JS::GCContext* gcx,
                                                      SliceBudget& budget) {
#ifdef DEBUG
  MOZ_ASSERT(!markOnBackgroundThreadDuringSweeping);
  assertNoMarkingWork();
  for (auto& marker : markers) {
    MOZ_ASSERT(marker->markColor() == MarkColor::Black);
  }
  MOZ_ASSERT(cellsToAssertNotGray.ref().empty());
#endif

  gcstats::AutoPhase ap(stats(), gcstats::PhaseKind::SWEEP_MARK);

  // Change state of current group to MarkBlackAndGray to restrict gray marking
  // to this group. Note that there may be pointers to the atoms zone, and these
  // will be marked through, as they are not marked with
  // TraceCrossCompartmentEdge.
  for (SweepGroupZonesIter zone(this); !zone.done(); zone.next()) {
    zone->changeGCState(zone->initialMarkingState(), Zone::MarkBlackAndGray);
  }

  AutoSetMarkColor setColorGray(marker(), MarkColor::Gray);

  // Mark incoming gray pointers from previously swept compartments.
  markIncomingGrayCrossCompartmentPointers();

  return Finished;
}

IncrementalProgress GCRuntime::markGrayRootsInCurrentGroup(
    JS::GCContext* gcx, SliceBudget& budget) {
  gcstats::AutoPhase ap(stats(), gcstats::PhaseKind::SWEEP_MARK);

  AutoSetMarkColor setColorGray(marker(), MarkColor::Gray);

  return markGrayRoots<SweepGroupZonesIter>(
      budget, gcstats::PhaseKind::SWEEP_MARK_GRAY);
}

IncrementalProgress GCRuntime::markGray(JS::GCContext* gcx,
                                        SliceBudget& budget) {
  gcstats::AutoPhase ap(stats(), gcstats::PhaseKind::SWEEP_MARK);

  if (markUntilBudgetExhausted(budget, AllowParallelMarking) == NotFinished) {
    return NotFinished;
  }

  return Finished;
}

IncrementalProgress GCRuntime::endMarkingSweepGroup(JS::GCContext* gcx,
                                                    SliceBudget& budget) {
#ifdef DEBUG
  MOZ_ASSERT(!markOnBackgroundThreadDuringSweeping);
  assertNoMarkingWork();
  for (auto& marker : markers) {
    MOZ_ASSERT(marker->markColor() == MarkColor::Black);
  }
  MOZ_ASSERT(!HasIncomingCrossCompartmentPointers(rt));
#endif

  gcstats::AutoPhase ap(stats(), gcstats::PhaseKind::SWEEP_MARK);

  if (markWeakReferencesInCurrentGroup(budget) == NotFinished) {
    return NotFinished;
  }

  AutoSetMarkColor setColorGray(marker(), MarkColor::Gray);

  // Mark transitively inside the current compartment group.
  if (markWeakReferencesInCurrentGroup(budget) == NotFinished) {
    return NotFinished;
  }

  MOZ_ASSERT(marker().isDrained());

  // We must not yield after this point before we start sweeping the group.
  safeToYield = false;

  MaybeCheckWeakMapMarking(this);

  return Finished;
}

// Causes the given WeakCache to be swept when run.
class ImmediateSweepWeakCacheTask : public GCParallelTask {
  Zone* zone;
  JS::detail::WeakCacheBase& cache;

  ImmediateSweepWeakCacheTask(const ImmediateSweepWeakCacheTask&) = delete;

 public:
  ImmediateSweepWeakCacheTask(GCRuntime* gc, Zone* zone,
                              JS::detail::WeakCacheBase& wc)
      : GCParallelTask(gc, gcstats::PhaseKind::SWEEP_WEAK_CACHES),
        zone(zone),
        cache(wc) {}

  ImmediateSweepWeakCacheTask(ImmediateSweepWeakCacheTask&& other)
      : GCParallelTask(std::move(other)),
        zone(other.zone),
        cache(other.cache) {}

  void run(AutoLockHelperThreadState& lock) override {
    AutoUnlockHelperThreadState unlock(lock);
    AutoSetThreadIsSweeping threadIsSweeping(zone);
    SweepingTracer trc(gc->rt);
    cache.traceWeak(&trc, &gc->storeBuffer());
  }
};

void GCRuntime::updateAtomsBitmap() {
  DenseBitmap marked;
  if (atomMarking.computeBitmapFromChunkMarkBits(rt, marked)) {
    for (GCZonesIter zone(this); !zone.done(); zone.next()) {
      atomMarking.refineZoneBitmapForCollectedZone(zone, marked);
    }
  } else {
    // Ignore OOM in computeBitmapFromChunkMarkBits. The
    // refineZoneBitmapForCollectedZone call can only remove atoms from the
    // zone bitmap, so it is conservative to just not call it.
  }

  atomMarking.markAtomsUsedByUncollectedZones(rt);

  // For convenience sweep these tables non-incrementally as part of bitmap
  // sweeping; they are likely to be much smaller than the main atoms table.
  SweepingTracer trc(rt);
  rt->symbolRegistry().traceWeak(&trc);
}

void GCRuntime::sweepCCWrappers() {
  SweepingTracer trc(rt);
  for (SweepGroupZonesIter zone(this); !zone.done(); zone.next()) {
    zone->traceWeakCCWEdges(&trc);
  }
}

void GCRuntime::sweepRealmGlobals() {
  SweepingTracer trc(rt);
  for (SweepGroupRealmsIter r(this); !r.done(); r.next()) {
    AutoSetThreadIsSweeping threadIsSweeping(r->zone());
    r->traceWeakGlobalEdge(&trc);
  }
}

void GCRuntime::sweepMisc() {
  SweepingTracer trc(rt);
  for (SweepGroupRealmsIter r(this); !r.done(); r.next()) {
    AutoSetThreadIsSweeping threadIsSweeping(r->zone());
    r->traceWeakSavedStacks(&trc);
    r->traceWeakRegExps(&trc);
  }
  for (SweepGroupCompartmentsIter c(this); !c.done(); c.next()) {
    AutoSetThreadIsSweeping threadIsSweeping(c->zone());
    c->traceWeakNativeIterators(&trc);
  }
}

void GCRuntime::sweepCompressionTasks() {
  JSRuntime* runtime = rt;

  // Attach finished compression tasks.
  AutoLockHelperThreadState lock;
  AttachFinishedCompressions(runtime, lock);
  SweepPendingCompressions(lock);
}

void GCRuntime::sweepWeakMaps() {
  SweepingTracer trc(rt);
  for (SweepGroupZonesIter zone(this); !zone.done(); zone.next()) {
    /* No need to look up any more weakmap keys from this sweep group. */
    AutoEnterOOMUnsafeRegion oomUnsafe;
    if (!zone->gcEphemeronEdges().clear()) {
      oomUnsafe.crash("clearing weak keys in beginSweepingSweepGroup()");
    }

    // Lock the storebuffer since this may access it when rehashing or resizing
    // the tables.
    AutoLockStoreBuffer lock(&storeBuffer());
    zone->sweepWeakMaps(&trc);
  }
}

void GCRuntime::sweepUniqueIds() {
  for (SweepGroupZonesIter zone(this); !zone.done(); zone.next()) {
    AutoSetThreadIsSweeping threadIsSweeping(zone);
    zone->sweepUniqueIds();
  }
}

void JS::Zone::sweepUniqueIds() {
  SweepingTracer trc(runtimeFromAnyThread());
  uniqueIds().traceWeak(&trc);
}

/* static */
bool UniqueIdGCPolicy::traceWeak(JSTracer* trc, Cell** keyp, uint64_t* valuep) {
  // Since this is only ever used for sweeping, we can optimize it for that
  // case. (Compacting GC updates this table manually when it moves a cell.)
  MOZ_ASSERT(trc->kind() == JS::TracerKind::Sweeping);
  return (*keyp)->isMarkedAny();
}

void GCRuntime::sweepFinalizationObserversOnMainThread() {
  // This calls back into the browser which expects to be called from the main
  // thread.
  gcstats::AutoPhase ap1(stats(), gcstats::PhaseKind::SWEEP_COMPARTMENTS);
  gcstats::AutoPhase ap2(stats(),
                         gcstats::PhaseKind::SWEEP_FINALIZATION_OBSERVERS);
  SweepingTracer trc(rt);
  AutoLockStoreBuffer lock(&storeBuffer());
  for (SweepGroupZonesIter zone(this); !zone.done(); zone.next()) {
    traceWeakFinalizationObserverEdges(&trc, zone);
  }
}

void GCRuntime::startTask(GCParallelTask& task,
                          AutoLockHelperThreadState& lock) {
  if (!CanUseExtraThreads()) {
    AutoUnlockHelperThreadState unlock(lock);
    task.runFromMainThread();
    stats().recordParallelPhase(task.phaseKind, task.duration());
    return;
  }

  task.startWithLockHeld(lock);
}

void GCRuntime::joinTask(GCParallelTask& task,
                         AutoLockHelperThreadState& lock) {
  gcstats::AutoPhase ap(stats(), gcstats::PhaseKind::JOIN_PARALLEL_TASKS);
  task.joinWithLockHeld(lock);
}

void GCRuntime::sweepDebuggerOnMainThread(JS::GCContext* gcx) {
  SweepingTracer trc(rt);
  AutoLockStoreBuffer lock(&storeBuffer());

  // Detach unreachable debuggers and global objects from each other.
  // This can modify weakmaps and so must happen before weakmap sweeping.
  DebugAPI::sweepAll(gcx);

  gcstats::AutoPhase ap(stats(), gcstats::PhaseKind::SWEEP_COMPARTMENTS);

  // Sweep debug environment information. This performs lookups in the Zone's
  // unique IDs table and so must not happen in parallel with sweeping that
  // table.
  {
    gcstats::AutoPhase ap2(stats(), gcstats::PhaseKind::SWEEP_MISC);
    for (SweepGroupRealmsIter r(rt); !r.done(); r.next()) {
      r->traceWeakDebugEnvironmentEdges(&trc);
    }
  }
}

void GCRuntime::sweepJitDataOnMainThread(JS::GCContext* gcx) {
  SweepingTracer trc(rt);
  {
    gcstats::AutoPhase ap(stats(), gcstats::PhaseKind::SWEEP_JIT_DATA);

    if (initialState != State::NotActive) {
      // Cancel any active or pending off thread compilations. We also did
      // this before marking (in DiscardJITCodeForGC) so this is a no-op
      // for non-incremental GCs.
      js::CancelOffThreadIonCompile(rt, JS::Zone::Sweep);
    }

    // Bug 1071218: the following method has not yet been refactored to
    // work on a single zone-group at once.

    // Sweep entries containing about-to-be-finalized JitCode and
    // update relocated TypeSet::Types inside the JitcodeGlobalTable.
    jit::JitRuntime::TraceWeakJitcodeGlobalTable(rt, &trc);
  }

  if (initialState != State::NotActive) {
    gcstats::AutoPhase apdc(stats(), gcstats::PhaseKind::SWEEP_DISCARD_CODE);
    for (SweepGroupZonesIter zone(this); !zone.done(); zone.next()) {
      zone->discardJitCode(gcx);
    }
  }

  // JitZone/JitRealm must be swept *after* discarding JIT code, because
  // Zone::discardJitCode might access CacheIRStubInfos deleted here.
  {
    gcstats::AutoPhase ap(stats(), gcstats::PhaseKind::SWEEP_JIT_DATA);

    for (SweepGroupRealmsIter r(rt); !r.done(); r.next()) {
      r->traceWeakEdgesInJitRealm(&trc);
    }

    for (SweepGroupZonesIter zone(this); !zone.done(); zone.next()) {
      if (jit::JitZone* jitZone = zone->jitZone()) {
        jitZone->traceWeak(&trc);
      }
    }
  }
}

using WeakCacheTaskVector =
    mozilla::Vector<ImmediateSweepWeakCacheTask, 0, SystemAllocPolicy>;

// Call a functor for all weak caches that need to be swept in the current
// sweep group.
template <typename Functor>
static inline bool IterateWeakCaches(JSRuntime* rt, Functor f) {
  for (SweepGroupZonesIter zone(rt); !zone.done(); zone.next()) {
    for (JS::detail::WeakCacheBase* cache : zone->weakCaches()) {
      if (!f(cache, zone.get())) {
        return false;
      }
    }
  }

  for (JS::detail::WeakCacheBase* cache : rt->weakCaches()) {
    if (!f(cache, nullptr)) {
      return false;
    }
  }

  return true;
}

static bool PrepareWeakCacheTasks(JSRuntime* rt,
                                  WeakCacheTaskVector* immediateTasks) {
  // Start incremental sweeping for caches that support it or add to a vector
  // of sweep tasks to run on a helper thread.

  MOZ_ASSERT(immediateTasks->empty());

  GCRuntime* gc = &rt->gc;
  bool ok =
      IterateWeakCaches(rt, [&](JS::detail::WeakCacheBase* cache, Zone* zone) {
        if (cache->empty()) {
          return true;
        }

        // Caches that support incremental sweeping will be swept later.
        if (zone && cache->setIncrementalBarrierTracer(&gc->sweepingTracer)) {
          return true;
        }

        return immediateTasks->emplaceBack(gc, zone, *cache);
      });

  if (!ok) {
    immediateTasks->clearAndFree();
  }

  return ok;
}

static void SweepAllWeakCachesOnMainThread(JSRuntime* rt) {
  // If we ran out of memory, do all the work on the main thread.
  gcstats::AutoPhase ap(rt->gc.stats(), gcstats::PhaseKind::SWEEP_WEAK_CACHES);
  SweepingTracer trc(rt);
  IterateWeakCaches(rt, [&](JS::detail::WeakCacheBase* cache, Zone* zone) {
    if (cache->needsIncrementalBarrier()) {
      cache->setIncrementalBarrierTracer(nullptr);
    }
    cache->traceWeak(&trc, &rt->gc.storeBuffer());
    return true;
  });
}

void GCRuntime::sweepEmbeddingWeakPointers(JS::GCContext* gcx) {
  using namespace gcstats;

  AutoLockStoreBuffer lock(&storeBuffer());

  AutoPhase ap(stats(), PhaseKind::FINALIZE_START);
  callFinalizeCallbacks(gcx, JSFINALIZE_GROUP_PREPARE);
  {
    AutoPhase ap2(stats(), PhaseKind::WEAK_ZONES_CALLBACK);
    callWeakPointerZonesCallbacks(&sweepingTracer);
  }
  {
    AutoPhase ap2(stats(), PhaseKind::WEAK_COMPARTMENT_CALLBACK);
    for (SweepGroupZonesIter zone(this); !zone.done(); zone.next()) {
      for (CompartmentsInZoneIter comp(zone); !comp.done(); comp.next()) {
        callWeakPointerCompartmentCallbacks(&sweepingTracer, comp);
      }
    }
  }
  callFinalizeCallbacks(gcx, JSFINALIZE_GROUP_START);
}

IncrementalProgress GCRuntime::beginSweepingSweepGroup(JS::GCContext* gcx,
                                                       SliceBudget& budget) {
  /*
   * Begin sweeping the group of zones in currentSweepGroup, performing
   * actions that must be done before yielding to caller.
   */

  using namespace gcstats;

  AutoSCC scc(stats(), sweepGroupIndex);

  bool sweepingAtoms = false;
  for (SweepGroupZonesIter zone(this); !zone.done(); zone.next()) {
    /* Set the GC state to sweeping. */
    zone->changeGCState(Zone::MarkBlackAndGray, Zone::Sweep);

    /* Purge the ArenaLists before sweeping. */
    zone->arenas.checkSweepStateNotInUse();
    zone->arenas.unmarkPreMarkedFreeCells();
    zone->arenas.clearFreeLists();

    if (zone->isAtomsZone()) {
      sweepingAtoms = true;
    }
  }

#ifdef JS_GC_ZEAL
  validateIncrementalMarking();
#endif

#ifdef DEBUG
  for (auto cell : cellsToAssertNotGray.ref()) {
    JS::AssertCellIsNotGray(cell);
  }
  cellsToAssertNotGray.ref().clearAndFree();
#endif

  // Updating the atom marking bitmaps. This marks atoms referenced by
  // uncollected zones so cannot be done in parallel with the other sweeping
  // work below.
  if (sweepingAtoms) {
    AutoPhase ap(stats(), PhaseKind::UPDATE_ATOMS_BITMAP);
    updateAtomsBitmap();
  }

  AutoSetThreadIsSweeping threadIsSweeping;

  // This must happen before sweeping realm globals.
  sweepDebuggerOnMainThread(gcx);

  // FinalizationRegistry sweeping touches weak maps and so must not run in
  // parallel with that. This triggers a read barrier and can add marking work
  // for zones that are still marking. Must happen before sweeping realm
  // globals.
  sweepFinalizationObserversOnMainThread();

  // This must happen before updating embedding weak pointers.
  sweepRealmGlobals();

  sweepEmbeddingWeakPointers(gcx);

  {
    AutoLockHelperThreadState lock;

    AutoPhase ap(stats(), PhaseKind::SWEEP_COMPARTMENTS);

    AutoRunParallelTask sweepCCWrappers(this, &GCRuntime::sweepCCWrappers,
                                        PhaseKind::SWEEP_CC_WRAPPER,
                                        GCUse::Sweeping, lock);
    AutoRunParallelTask sweepMisc(this, &GCRuntime::sweepMisc,
                                  PhaseKind::SWEEP_MISC, GCUse::Sweeping, lock);
    AutoRunParallelTask sweepCompTasks(this, &GCRuntime::sweepCompressionTasks,
                                       PhaseKind::SWEEP_COMPRESSION,
                                       GCUse::Sweeping, lock);
    AutoRunParallelTask sweepWeakMaps(this, &GCRuntime::sweepWeakMaps,
                                      PhaseKind::SWEEP_WEAKMAPS,
                                      GCUse::Sweeping, lock);
    AutoRunParallelTask sweepUniqueIds(this, &GCRuntime::sweepUniqueIds,
                                       PhaseKind::SWEEP_UNIQUEIDS,
                                       GCUse::Sweeping, lock);

    WeakCacheTaskVector sweepCacheTasks;
    bool canSweepWeakCachesOffThread =
        PrepareWeakCacheTasks(rt, &sweepCacheTasks);
    if (canSweepWeakCachesOffThread) {
      weakCachesToSweep.ref().emplace(currentSweepGroup);
      for (auto& task : sweepCacheTasks) {
        startTask(task, lock);
      }
    }

    {
      AutoUnlockHelperThreadState unlock(lock);
      sweepJitDataOnMainThread(gcx);

      if (!canSweepWeakCachesOffThread) {
        MOZ_ASSERT(sweepCacheTasks.empty());
        SweepAllWeakCachesOnMainThread(rt);
      }
    }

    for (auto& task : sweepCacheTasks) {
      joinTask(task, lock);
    }
  }

  if (sweepingAtoms) {
    startSweepingAtomsTable();
  }

  // Queue all GC things in all zones for sweeping, either on the foreground
  // or on the background thread.

  for (SweepGroupZonesIter zone(this); !zone.done(); zone.next()) {
    for (const auto& phase : BackgroundFinalizePhases) {
      initBackgroundSweep(zone, gcx, phase);
    }

    zone->arenas.queueForegroundThingsForSweep();
  }

  MOZ_ASSERT(!sweepZone);

  safeToYield = true;
  markOnBackgroundThreadDuringSweeping = CanUseExtraThreads();

  return Finished;
}

#ifdef JS_GC_ZEAL
bool GCRuntime::shouldYieldForZeal(ZealMode mode) {
  bool yield = useZeal && hasZealMode(mode);

  // Only yield on the first sweep slice for this mode.
  bool firstSweepSlice = initialState != State::Sweep;
  if (mode == ZealMode::IncrementalMultipleSlices && !firstSweepSlice) {
    yield = false;
  }

  return yield;
}
#endif

IncrementalProgress GCRuntime::endSweepingSweepGroup(JS::GCContext* gcx,
                                                     SliceBudget& budget) {
  // This is to prevent a race between markTask checking the zone state and
  // us changing it below.
  if (joinBackgroundMarkTask() == NotFinished) {
    return NotFinished;
  }

  assertNoMarkingWork();

  // Disable background marking during sweeping until we start sweeping the next
  // zone group.
  markOnBackgroundThreadDuringSweeping = false;

  {
    gcstats::AutoPhase ap(stats(), gcstats::PhaseKind::FINALIZE_END);
    AutoLockStoreBuffer lock(&storeBuffer());
    callFinalizeCallbacks(gcx, JSFINALIZE_GROUP_END);
  }

  /* Free LIFO blocks on a background thread if possible. */
  startBackgroundFree();

  /* Update the GC state for zones we have swept. */
  for (SweepGroupZonesIter zone(this); !zone.done(); zone.next()) {
    if (jit::JitZone* jitZone = zone->jitZone()) {
      // Clear out any small pools that we're hanging on to.
      jitZone->execAlloc().purge();
    }
    AutoLockGC lock(this);
    zone->changeGCState(Zone::Sweep, Zone::Finished);
    zone->arenas.unmarkPreMarkedFreeCells();
    zone->arenas.checkNoArenasToUpdate();
    zone->pretenuring.clearCellCountsInNewlyCreatedArenas();
  }

  /*
   * Start background thread to sweep zones if required, sweeping any atoms
   * zones last if present.
   */
  ZoneList zones;
  for (SweepGroupZonesIter zone(this); !zone.done(); zone.next()) {
    if (zone->isAtomsZone()) {
      zones.append(zone);
    } else {
      zones.prepend(zone);
    }
  }

  queueZonesAndStartBackgroundSweep(std::move(zones));

  return Finished;
}

IncrementalProgress GCRuntime::markDuringSweeping(JS::GCContext* gcx,
                                                  SliceBudget& budget) {
  MOZ_ASSERT(markTask.isIdle());

  if (markOnBackgroundThreadDuringSweeping) {
    if (!marker().isDrained()) {
      AutoLockHelperThreadState lock;
      MOZ_ASSERT(markTask.isIdle(lock));
      markTask.setBudget(budget);
      markTask.startOrRunIfIdle(lock);
    }
    return Finished;  // This means don't yield to the mutator here.
  }

  gcstats::AutoPhase ap(stats(), gcstats::PhaseKind::SWEEP_MARK);
  return markUntilBudgetExhausted(budget, AllowParallelMarking);
}

void GCRuntime::beginSweepPhase(JS::GCReason reason, AutoGCSession& session) {
  /*
   * Sweep phase.
   *
   * Finalize as we sweep, outside of lock but with RuntimeHeapIsBusy()
   * true so that any attempt to allocate a GC-thing from a finalizer will
   * fail, rather than nest badly and leave the unmarked newborn to be swept.
   */

  MOZ_ASSERT(!abortSweepAfterCurrentGroup);
  MOZ_ASSERT(!markOnBackgroundThreadDuringSweeping);

#ifdef DEBUG
  releaseHeldRelocatedArenas();
  verifyAllChunks();
#endif

#ifdef JS_GC_ZEAL
  computeNonIncrementalMarkingForValidation(session);
#endif

  gcstats::AutoPhase ap(stats(), gcstats::PhaseKind::SWEEP);

  AssertNoWrappersInGrayList(rt);
  dropStringWrappers();

  groupZonesForSweeping(reason);

  sweepActions->assertFinished();
}

bool GCRuntime::foregroundFinalize(JS::GCContext* gcx, Zone* zone,
                                   AllocKind thingKind,
                                   SliceBudget& sliceBudget,
                                   SortedArenaList& sweepList) {
  ArenaLists& lists = zone->arenas;
  lists.checkNoArenasToUpdateForKind(thingKind);

  // Non-empty arenas are reused for use for new allocations as soon as the
  // finalizers for that allocation kind have run. Empty arenas are only
  // released when everything in the zone has been swept (see
  // GCRuntime::sweepBackgroundThings for more details).
  if (!FinalizeArenas(gcx, lists.collectingArenaList(thingKind), sweepList,
                      thingKind, sliceBudget)) {
    // Copy the current contents of sweepList so that ArenaIter can find them.
    lists.setIncrementalSweptArenas(thingKind, sweepList);
    return false;
  }

  sweepList.extractEmpty(&lists.savedEmptyArenas.ref());
  lists.mergeFinalizedArenas(thingKind, sweepList);
  lists.clearIncrementalSweptArenas();

  return true;
}

BackgroundMarkTask::BackgroundMarkTask(GCRuntime* gc)
    : GCParallelTask(gc, gcstats::PhaseKind::SWEEP_MARK, GCUse::Marking),
      budget(SliceBudget::unlimited()) {}

void js::gc::BackgroundMarkTask::run(AutoLockHelperThreadState& lock) {
  AutoUnlockHelperThreadState unlock(lock);

  // Time reporting is handled separately for parallel tasks.
  gc->sweepMarkResult = gc->markUntilBudgetExhausted(
      this->budget, GCRuntime::SingleThreadedMarking, DontReportMarkTime);
}

IncrementalProgress GCRuntime::joinBackgroundMarkTask() {
  AutoLockHelperThreadState lock;
  if (markTask.isIdle(lock)) {
    return Finished;
  }

  joinTask(markTask, lock);

  IncrementalProgress result = sweepMarkResult;
  sweepMarkResult = Finished;
  return result;
}

template <typename T>
static void SweepThing(JS::GCContext* gcx, T* thing) {
  if (!TenuredThingIsMarkedAny(thing)) {
    thing->sweep(gcx);
  }
}

template <typename T>
static bool SweepArenaList(JS::GCContext* gcx, Arena** arenasToSweep,
                           SliceBudget& sliceBudget) {
  while (Arena* arena = *arenasToSweep) {
    MOZ_ASSERT(arena->zone->isGCSweeping());

    for (ArenaCellIterUnderGC cell(arena); !cell.done(); cell.next()) {
      SweepThing(gcx, cell.as<T>());
    }

    Arena* next = arena->next;
    MOZ_ASSERT_IF(next, next->zone == arena->zone);
    *arenasToSweep = next;

    AllocKind kind = MapTypeToAllocKind<T>::kind;
    sliceBudget.step(Arena::thingsPerArena(kind));
    if (sliceBudget.isOverBudget()) {
      return false;
    }
  }

  return true;
}

void GCRuntime::startSweepingAtomsTable() {
  auto& maybeAtoms = maybeAtomsToSweep.ref();
  MOZ_ASSERT(maybeAtoms.isNothing());

  AtomsTable* atomsTable = rt->atomsForSweeping();
  if (!atomsTable) {
    return;
  }

  // Create secondary tables to hold new atoms added while we're sweeping the
  // main tables incrementally.
  if (!atomsTable->startIncrementalSweep(maybeAtoms)) {
    SweepingTracer trc(rt);
    atomsTable->traceWeak(&trc);
  }
}

IncrementalProgress GCRuntime::sweepAtomsTable(JS::GCContext* gcx,
                                               SliceBudget& budget) {
  if (!atomsZone()->isGCSweeping()) {
    return Finished;
  }

  gcstats::AutoPhase ap(stats(), gcstats::PhaseKind::SWEEP_ATOMS_TABLE);

  auto& maybeAtoms = maybeAtomsToSweep.ref();
  if (!maybeAtoms) {
    return Finished;
  }

  if (!rt->atomsForSweeping()->sweepIncrementally(maybeAtoms.ref(), budget)) {
    return NotFinished;
  }

  maybeAtoms.reset();

  return Finished;
}

static size_t IncrementalSweepWeakCache(GCRuntime* gc,
                                        const WeakCacheToSweep& item) {
  AutoSetThreadIsSweeping threadIsSweeping(item.zone);

  JS::detail::WeakCacheBase* cache = item.cache;
  MOZ_ASSERT(cache->needsIncrementalBarrier());

  SweepingTracer trc(gc->rt);
  size_t steps = cache->traceWeak(&trc, &gc->storeBuffer());
  cache->setIncrementalBarrierTracer(nullptr);

  return steps;
}

WeakCacheSweepIterator::WeakCacheSweepIterator(JS::Zone* sweepGroup)
    : sweepZone(sweepGroup), sweepCache(sweepZone->weakCaches().getFirst()) {
  settle();
}

bool WeakCacheSweepIterator::done() const { return !sweepZone; }

WeakCacheToSweep WeakCacheSweepIterator::get() const {
  MOZ_ASSERT(!done());

  return {sweepCache, sweepZone};
}

void WeakCacheSweepIterator::next() {
  MOZ_ASSERT(!done());

  sweepCache = sweepCache->getNext();
  settle();
}

void WeakCacheSweepIterator::settle() {
  while (sweepZone) {
    while (sweepCache && !sweepCache->needsIncrementalBarrier()) {
      sweepCache = sweepCache->getNext();
    }

    if (sweepCache) {
      break;
    }

    sweepZone = sweepZone->nextNodeInGroup();
    if (sweepZone) {
      sweepCache = sweepZone->weakCaches().getFirst();
    }
  }

  MOZ_ASSERT((!sweepZone && !sweepCache) ||
             (sweepCache && sweepCache->needsIncrementalBarrier()));
}

IncrementalProgress GCRuntime::sweepWeakCaches(JS::GCContext* gcx,
                                               SliceBudget& budget) {
  if (weakCachesToSweep.ref().isNothing()) {
    return Finished;
  }

  gcstats::AutoPhase ap(stats(), gcstats::PhaseKind::SWEEP_COMPARTMENTS);

  WeakCacheSweepIterator& work = weakCachesToSweep.ref().ref();

  AutoLockHelperThreadState lock;

  {
    AutoRunParallelWork runWork(this, IncrementalSweepWeakCache,
                                gcstats::PhaseKind::SWEEP_WEAK_CACHES,
                                GCUse::Sweeping, work, budget, lock);
    AutoUnlockHelperThreadState unlock(lock);
  }

  if (work.done()) {
    weakCachesToSweep.ref().reset();
    return Finished;
  }

  return NotFinished;
}

IncrementalProgress GCRuntime::finalizeAllocKind(JS::GCContext* gcx,
                                                 SliceBudget& budget) {
  MOZ_ASSERT(sweepZone->isGCSweeping());

  // Set the number of things per arena for this AllocKind.
  size_t thingsPerArena = Arena::thingsPerArena(sweepAllocKind);
  auto& sweepList = incrementalSweepList.ref();
  sweepList.setThingsPerArena(thingsPerArena);

  AutoSetThreadIsFinalizing threadIsFinalizing(gcx);

  if (!foregroundFinalize(gcx, sweepZone, sweepAllocKind, budget, sweepList)) {
    return NotFinished;
  }

  // Reset the slots of the sweep list that we used.
  sweepList.reset(thingsPerArena);

  return Finished;
}

IncrementalProgress GCRuntime::sweepPropMapTree(JS::GCContext* gcx,
                                                SliceBudget& budget) {
  // Remove dead SharedPropMaps from the tree. This happens incrementally on the
  // main thread. PropMaps are finalized later on the a background thread.

  gcstats::AutoPhase ap(stats(), gcstats::PhaseKind::SWEEP_PROP_MAP);

  ArenaLists& al = sweepZone->arenas;

  if (!SweepArenaList<CompactPropMap>(
          gcx, &al.gcCompactPropMapArenasToUpdate.ref(), budget)) {
    return NotFinished;
  }
  if (!SweepArenaList<NormalPropMap>(
          gcx, &al.gcNormalPropMapArenasToUpdate.ref(), budget)) {
    return NotFinished;
  }

  return Finished;
}

// An iterator for a standard container that provides an STL-like begin()/end()
// interface. This iterator provides a done()/get()/next() style interface.
template <typename Container>
class ContainerIter {
  using Iter = decltype(std::declval<const Container>().begin());
  using Elem = decltype(*std::declval<Iter>());

  Iter iter;
  const Iter end;

 public:
  explicit ContainerIter(const Container& container)
      : iter(container.begin()), end(container.end()) {}

  bool done() const { return iter == end; }

  Elem get() const { return *iter; }

  void next() {
    MOZ_ASSERT(!done());
    ++iter;
  }
};

// IncrementalIter is a template class that makes a normal iterator into one
// that can be used to perform incremental work by using external state that
// persists between instantiations. The state is only initialised on the first
// use and subsequent uses carry on from the previous state.
template <typename Iter>
struct IncrementalIter {
  using State = mozilla::Maybe<Iter>;
  using Elem = decltype(std::declval<Iter>().get());

 private:
  State& maybeIter;

 public:
  template <typename... Args>
  explicit IncrementalIter(State& maybeIter, Args&&... args)
      : maybeIter(maybeIter) {
    if (maybeIter.isNothing()) {
      maybeIter.emplace(std::forward<Args>(args)...);
    }
  }

  ~IncrementalIter() {
    if (done()) {
      maybeIter.reset();
    }
  }

  bool done() const { return maybeIter.ref().done(); }

  Elem get() const { return maybeIter.ref().get(); }

  void next() { maybeIter.ref().next(); }
};

// Iterate through the sweep groups created by
// GCRuntime::groupZonesForSweeping().
class js::gc::SweepGroupsIter {
  GCRuntime* gc;

 public:
  explicit SweepGroupsIter(JSRuntime* rt) : gc(&rt->gc) {
    MOZ_ASSERT(gc->currentSweepGroup);
  }

  bool done() const { return !gc->currentSweepGroup; }

  Zone* get() const { return gc->currentSweepGroup; }

  void next() {
    MOZ_ASSERT(!done());
    gc->getNextSweepGroup();
  }
};

namespace sweepaction {

// Implementation of the SweepAction interface that calls a method on GCRuntime.
class SweepActionCall final : public SweepAction {
  using Method = IncrementalProgress (GCRuntime::*)(JS::GCContext* gcx,
                                                    SliceBudget& budget);

  Method method;

 public:
  explicit SweepActionCall(Method m) : method(m) {}
  IncrementalProgress run(Args& args) override {
    return (args.gc->*method)(args.gcx, args.budget);
  }
  void assertFinished() const override {}
};

// Implementation of the SweepAction interface that yields in a specified zeal
// mode.
class SweepActionMaybeYield final : public SweepAction {
#ifdef JS_GC_ZEAL
  ZealMode mode;
  bool isYielding;
#endif

 public:
  explicit SweepActionMaybeYield(ZealMode mode)
#ifdef JS_GC_ZEAL
      : mode(mode),
        isYielding(false)
#endif
  {
  }

  IncrementalProgress run(Args& args) override {
#ifdef JS_GC_ZEAL
    if (!isYielding && args.gc->shouldYieldForZeal(mode)) {
      isYielding = true;
      return NotFinished;
    }

    isYielding = false;
#endif
    return Finished;
  }

  void assertFinished() const override { MOZ_ASSERT(!isYielding); }

  // These actions should be skipped if GC zeal is not configured.
#ifndef JS_GC_ZEAL
  bool shouldSkip() override { return true; }
#endif
};

// Implementation of the SweepAction interface that calls a list of actions in
// sequence.
class SweepActionSequence final : public SweepAction {
  using ActionVector = Vector<UniquePtr<SweepAction>, 0, SystemAllocPolicy>;
  using Iter = IncrementalIter<ContainerIter<ActionVector>>;

  ActionVector actions;
  typename Iter::State iterState;

 public:
  bool init(UniquePtr<SweepAction>* acts, size_t count) {
    for (size_t i = 0; i < count; i++) {
      auto& action = acts[i];
      if (!action) {
        return false;
      }
      if (action->shouldSkip()) {
        continue;
      }
      if (!actions.emplaceBack(std::move(action))) {
        return false;
      }
    }
    return true;
  }

  IncrementalProgress run(Args& args) override {
    for (Iter iter(iterState, actions); !iter.done(); iter.next()) {
      if (iter.get()->run(args) == NotFinished) {
        return NotFinished;
      }
    }
    return Finished;
  }

  void assertFinished() const override {
    MOZ_ASSERT(iterState.isNothing());
    for (const auto& action : actions) {
      action->assertFinished();
    }
  }
};

template <typename Iter, typename Init>
class SweepActionForEach final : public SweepAction {
  using Elem = decltype(std::declval<Iter>().get());
  using IncrIter = IncrementalIter<Iter>;

  Init iterInit;
  Elem* elemOut;
  UniquePtr<SweepAction> action;
  typename IncrIter::State iterState;

 public:
  SweepActionForEach(const Init& init, Elem* maybeElemOut,
                     UniquePtr<SweepAction> action)
      : iterInit(init), elemOut(maybeElemOut), action(std::move(action)) {}

  IncrementalProgress run(Args& args) override {
    MOZ_ASSERT_IF(elemOut, *elemOut == Elem());
    auto clearElem = mozilla::MakeScopeExit([&] { setElem(Elem()); });
    for (IncrIter iter(iterState, iterInit); !iter.done(); iter.next()) {
      setElem(iter.get());
      if (action->run(args) == NotFinished) {
        return NotFinished;
      }
    }
    return Finished;
  }

  void assertFinished() const override {
    MOZ_ASSERT(iterState.isNothing());
    MOZ_ASSERT_IF(elemOut, *elemOut == Elem());
    action->assertFinished();
  }

 private:
  void setElem(const Elem& value) {
    if (elemOut) {
      *elemOut = value;
    }
  }
};

static UniquePtr<SweepAction> Call(IncrementalProgress (GCRuntime::*method)(
    JS::GCContext* gcx, SliceBudget& budget)) {
  return MakeUnique<SweepActionCall>(method);
}

static UniquePtr<SweepAction> MaybeYield(ZealMode zealMode) {
  return MakeUnique<SweepActionMaybeYield>(zealMode);
}

template <typename... Rest>
static UniquePtr<SweepAction> Sequence(UniquePtr<SweepAction> first,
                                       Rest... rest) {
  UniquePtr<SweepAction> actions[] = {std::move(first), std::move(rest)...};
  auto seq = MakeUnique<SweepActionSequence>();
  if (!seq || !seq->init(actions, std::size(actions))) {
    return nullptr;
  }

  return UniquePtr<SweepAction>(std::move(seq));
}

static UniquePtr<SweepAction> RepeatForSweepGroup(
    JSRuntime* rt, UniquePtr<SweepAction> action) {
  if (!action) {
    return nullptr;
  }

  using Action = SweepActionForEach<SweepGroupsIter, JSRuntime*>;
  return js::MakeUnique<Action>(rt, nullptr, std::move(action));
}

static UniquePtr<SweepAction> ForEachZoneInSweepGroup(
    JSRuntime* rt, Zone** zoneOut, UniquePtr<SweepAction> action) {
  if (!action) {
    return nullptr;
  }

  using Action = SweepActionForEach<SweepGroupZonesIter, JSRuntime*>;
  return js::MakeUnique<Action>(rt, zoneOut, std::move(action));
}

static UniquePtr<SweepAction> ForEachAllocKind(AllocKinds kinds,
                                               AllocKind* kindOut,
                                               UniquePtr<SweepAction> action) {
  if (!action) {
    return nullptr;
  }

  using Action = SweepActionForEach<ContainerIter<AllocKinds>, AllocKinds>;
  return js::MakeUnique<Action>(kinds, kindOut, std::move(action));
}

}  // namespace sweepaction

bool GCRuntime::initSweepActions() {
  using namespace sweepaction;
  using sweepaction::Call;

  sweepActions.ref() = RepeatForSweepGroup(
      rt,
      Sequence(
          Call(&GCRuntime::beginMarkingSweepGroup),
          Call(&GCRuntime::markGrayRootsInCurrentGroup),
          MaybeYield(ZealMode::YieldWhileGrayMarking),
          Call(&GCRuntime::markGray), Call(&GCRuntime::endMarkingSweepGroup),
          Call(&GCRuntime::beginSweepingSweepGroup),
          MaybeYield(ZealMode::IncrementalMultipleSlices),
          MaybeYield(ZealMode::YieldBeforeSweepingAtoms),
          Call(&GCRuntime::sweepAtomsTable),
          MaybeYield(ZealMode::YieldBeforeSweepingCaches),
          Call(&GCRuntime::sweepWeakCaches),
          ForEachZoneInSweepGroup(
              rt, &sweepZone.ref(),
              Sequence(MaybeYield(ZealMode::YieldBeforeSweepingObjects),
                       ForEachAllocKind(ForegroundObjectFinalizePhase.kinds,
                                        &sweepAllocKind.ref(),
                                        Call(&GCRuntime::finalizeAllocKind)),
                       MaybeYield(ZealMode::YieldBeforeSweepingNonObjects),
                       ForEachAllocKind(ForegroundNonObjectFinalizePhase.kinds,
                                        &sweepAllocKind.ref(),
                                        Call(&GCRuntime::finalizeAllocKind)),
                       MaybeYield(ZealMode::YieldBeforeSweepingPropMapTrees),
                       Call(&GCRuntime::sweepPropMapTree))),
          Call(&GCRuntime::endSweepingSweepGroup)));

  return sweepActions != nullptr;
}

IncrementalProgress GCRuntime::performSweepActions(SliceBudget& budget) {
  AutoMajorGCProfilerEntry s(this);
  gcstats::AutoPhase ap(stats(), gcstats::PhaseKind::SWEEP);

  JS::GCContext* gcx = rt->gcContext();
  AutoSetThreadIsSweeping threadIsSweeping(gcx);
  AutoPoisonFreedJitCode pjc(gcx);

  // Don't trigger pre-barriers when finalizing.
  AutoDisableBarriers disableBarriers(this);

  // Drain the mark stack, possibly in a parallel task if we're in a part of
  // sweeping that allows it.
  //
  // In the first sweep slice where we must not yield to the mutator until we've
  // starting sweeping a sweep group but in that case the stack must be empty
  // already.

#ifdef DEBUG
  MOZ_ASSERT(initialState <= State::Sweep);
  if (initialState != State::Sweep) {
    assertNoMarkingWork();
  }
#endif

  if (initialState == State::Sweep &&
      markDuringSweeping(gcx, budget) == NotFinished) {
    return NotFinished;
  }

  // Then continue running sweep actions.

  SweepAction::Args args{this, gcx, budget};
  IncrementalProgress sweepProgress = sweepActions->run(args);
  IncrementalProgress markProgress = joinBackgroundMarkTask();

  if (sweepProgress == Finished && markProgress == Finished) {
    return Finished;
  }

  MOZ_ASSERT(isIncremental);
  return NotFinished;
}

bool GCRuntime::allCCVisibleZonesWereCollected() {
  // Calculate whether the gray marking state is now valid.
  //
  // The gray bits change from invalid to valid if we finished a full GC from
  // the point of view of the cycle collector. We ignore the following:
  //
  //  - Helper thread zones, as these are not reachable from the main heap.
  //  - The atoms zone, since strings and symbols are never marked gray.
  //  - Empty zones.
  //
  // These exceptions ensure that when the CC requests a full GC the gray mark
  // state ends up valid even it we don't collect all of the zones.

  for (ZonesIter zone(this, SkipAtoms); !zone.done(); zone.next()) {
    if (!zone->isCollecting() && !zone->arenas.arenaListsAreEmpty()) {
      return false;
    }
  }

  return true;
}

void GCRuntime::endSweepPhase(bool destroyingRuntime) {
  MOZ_ASSERT(!markOnBackgroundThreadDuringSweeping);

  sweepActions->assertFinished();

  gcstats::AutoPhase ap(stats(), gcstats::PhaseKind::SWEEP);

  MOZ_ASSERT_IF(destroyingRuntime, !useBackgroundThreads);

  {
    gcstats::AutoPhase ap(stats(), gcstats::PhaseKind::DESTROY);

    // Sweep shared script bytecode now all zones have been swept and finalizers
    // for BaseScripts have released their references.
    SweepScriptData(rt);
  }

  {
    gcstats::AutoPhase ap(stats(), gcstats::PhaseKind::FINALIZE_END);
    AutoLockStoreBuffer lock(&storeBuffer());
    callFinalizeCallbacks(rt->gcContext(), JSFINALIZE_COLLECTION_END);

    if (allCCVisibleZonesWereCollected()) {
      grayBitsValid = true;
    }
  }

  if (isIncremental) {
    findDeadCompartments();
  }

#ifdef JS_GC_ZEAL
  finishMarkingValidation();
#endif

#ifdef DEBUG
  for (ZonesIter zone(this, WithAtoms); !zone.done(); zone.next()) {
    for (auto i : AllAllocKinds()) {
      MOZ_ASSERT_IF(!IsBackgroundFinalized(i) || !useBackgroundThreads,
                    zone->arenas.collectingArenaList(i).isEmpty());
    }
  }
#endif

  AssertNoWrappersInGrayList(rt);
}