forked from phoboslab/JavaScriptCore-iOS
-
Notifications
You must be signed in to change notification settings - Fork 0
Expand file tree
/
Copy pathHeap.cpp
More file actions
1101 lines (933 loc) · 30.9 KB
/
Heap.cpp
File metadata and controls
1101 lines (933 loc) · 30.9 KB
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
/*
* Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2011, 2013 Apple Inc. All rights reserved.
* Copyright (C) 2007 Eric Seidel <[email protected]>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*
*/
#include "config.h"
#include "Heap.h"
#include "CodeBlock.h"
#include "ConservativeRoots.h"
#include "CopiedSpace.h"
#include "CopiedSpaceInlines.h"
#include "CopyVisitorInlines.h"
#include "DFGWorklist.h"
#include "DelayedReleaseScope.h"
#include "GCActivityCallback.h"
#include "GCIncomingRefCountedSetInlines.h"
#include "HeapIterationScope.h"
#include "HeapRootVisitor.h"
#include "HeapStatistics.h"
#include "IncrementalSweeper.h"
#include "Interpreter.h"
#include "JSGlobalObject.h"
#include "JSLock.h"
#include "JSONObject.h"
#include "Operations.h"
#include "RecursiveAllocationScope.h"
#include "Tracing.h"
#include "UnlinkedCodeBlock.h"
#include "VM.h"
#include "WeakSetInlines.h"
#include <algorithm>
#include <wtf/RAMSize.h>
#include <wtf/CurrentTime.h>
using namespace std;
using namespace JSC;
namespace JSC {
namespace {
static const size_t largeHeapSize = 32 * MB; // About 1.5X the average webpage.
static const size_t smallHeapSize = 1 * MB; // Matches the FastMalloc per-thread cache.
#define ENABLE_GC_LOGGING 0
#if ENABLE(GC_LOGGING)
#if COMPILER(CLANG)
#define DEFINE_GC_LOGGING_GLOBAL(type, name, arguments) \
_Pragma("clang diagnostic push") \
_Pragma("clang diagnostic ignored \"-Wglobal-constructors\"") \
_Pragma("clang diagnostic ignored \"-Wexit-time-destructors\"") \
static type name arguments; \
_Pragma("clang diagnostic pop")
#else
#define DEFINE_GC_LOGGING_GLOBAL(type, name, arguments) \
static type name arguments;
#endif // COMPILER(CLANG)
struct GCTimer {
GCTimer(const char* name)
: m_time(0)
, m_min(100000000)
, m_max(0)
, m_count(0)
, m_name(name)
{
}
~GCTimer()
{
dataLogF("%s: %.2lfms (avg. %.2lf, min. %.2lf, max. %.2lf)\n", m_name, m_time * 1000, m_time * 1000 / m_count, m_min*1000, m_max*1000);
}
double m_time;
double m_min;
double m_max;
size_t m_count;
const char* m_name;
};
struct GCTimerScope {
GCTimerScope(GCTimer* timer)
: m_timer(timer)
, m_start(WTF::monotonicallyIncreasingTime())
{
}
~GCTimerScope()
{
double delta = WTF::monotonicallyIncreasingTime() - m_start;
if (delta < m_timer->m_min)
m_timer->m_min = delta;
if (delta > m_timer->m_max)
m_timer->m_max = delta;
m_timer->m_count++;
m_timer->m_time += delta;
}
GCTimer* m_timer;
double m_start;
};
struct GCCounter {
GCCounter(const char* name)
: m_name(name)
, m_count(0)
, m_total(0)
, m_min(10000000)
, m_max(0)
{
}
void count(size_t amount)
{
m_count++;
m_total += amount;
if (amount < m_min)
m_min = amount;
if (amount > m_max)
m_max = amount;
}
~GCCounter()
{
dataLogF("%s: %zu values (avg. %zu, min. %zu, max. %zu)\n", m_name, m_total, m_total / m_count, m_min, m_max);
}
const char* m_name;
size_t m_count;
size_t m_total;
size_t m_min;
size_t m_max;
};
#define GCPHASE(name) DEFINE_GC_LOGGING_GLOBAL(GCTimer, name##Timer, (#name)); GCTimerScope name##TimerScope(&name##Timer)
#define COND_GCPHASE(cond, name1, name2) DEFINE_GC_LOGGING_GLOBAL(GCTimer, name1##Timer, (#name1)); DEFINE_GC_LOGGING_GLOBAL(GCTimer, name2##Timer, (#name2)); GCTimerScope name1##CondTimerScope(cond ? &name1##Timer : &name2##Timer)
#define GCCOUNTER(name, value) do { DEFINE_GC_LOGGING_GLOBAL(GCCounter, name##Counter, (#name)); name##Counter.count(value); } while (false)
#else
#define GCPHASE(name) do { } while (false)
#define COND_GCPHASE(cond, name1, name2) do { } while (false)
#define GCCOUNTER(name, value) do { } while (false)
#endif
static inline size_t minHeapSize(HeapType heapType, size_t ramSize)
{
if (heapType == LargeHeap)
return min(largeHeapSize, ramSize / 4);
return smallHeapSize;
}
static inline size_t proportionalHeapSize(size_t heapSize, size_t ramSize)
{
// Try to stay under 1/2 RAM size to leave room for the DOM, rendering, networking, etc.
if (heapSize < ramSize / 4)
return 2 * heapSize;
if (heapSize < ramSize / 2)
return 1.5 * heapSize;
return 1.25 * heapSize;
}
static inline bool isValidSharedInstanceThreadState(VM* vm)
{
return vm->currentThreadIsHoldingAPILock();
}
static inline bool isValidThreadState(VM* vm)
{
if (vm->identifierTable != wtfThreadData().currentIdentifierTable())
return false;
if (vm->isSharedInstance() && !isValidSharedInstanceThreadState(vm))
return false;
return true;
}
struct MarkObject : public MarkedBlock::VoidFunctor {
void operator()(JSCell* cell)
{
if (cell->isZapped())
return;
Heap::heap(cell)->setMarked(cell);
}
};
struct Count : public MarkedBlock::CountFunctor {
void operator()(JSCell*) { count(1); }
};
struct CountIfGlobalObject : MarkedBlock::CountFunctor {
void operator()(JSCell* cell) {
if (!cell->isObject())
return;
if (!asObject(cell)->isGlobalObject())
return;
count(1);
}
};
class RecordType {
public:
typedef PassOwnPtr<TypeCountSet> ReturnType;
RecordType();
void operator()(JSCell*);
ReturnType returnValue();
private:
const char* typeName(JSCell*);
OwnPtr<TypeCountSet> m_typeCountSet;
};
inline RecordType::RecordType()
: m_typeCountSet(adoptPtr(new TypeCountSet))
{
}
inline const char* RecordType::typeName(JSCell* cell)
{
const ClassInfo* info = cell->classInfo();
if (!info || !info->className)
return "[unknown]";
return info->className;
}
inline void RecordType::operator()(JSCell* cell)
{
m_typeCountSet->add(typeName(cell));
}
inline PassOwnPtr<TypeCountSet> RecordType::returnValue()
{
return m_typeCountSet.release();
}
} // anonymous namespace
Heap::Heap(VM* vm, HeapType heapType)
: m_heapType(heapType)
, m_ramSize(ramSize())
, m_minBytesPerCycle(minHeapSize(m_heapType, m_ramSize))
, m_sizeAfterLastCollect(0)
, m_bytesAllocatedThisCycle(0)
, m_bytesAbandonedThisCycle(0)
, m_maxEdenSize(m_minBytesPerCycle)
, m_maxHeapSize(m_minBytesPerCycle)
, m_shouldDoFullCollection(false)
, m_totalBytesVisited(0)
, m_totalBytesCopied(0)
, m_operationInProgress(NoOperation)
, m_blockAllocator()
, m_objectSpace(this)
, m_storageSpace(this)
, m_extraMemoryUsage(0)
, m_machineThreads(this)
, m_sharedData(vm)
, m_slotVisitor(m_sharedData)
, m_copyVisitor(m_sharedData)
, m_handleSet(vm)
, m_isSafeToCollect(false)
, m_writeBarrierBuffer(256)
, m_vm(vm)
, m_lastGCLength(0)
, m_lastCodeDiscardTime(WTF::monotonicallyIncreasingTime())
, m_activityCallback(DefaultGCActivityCallback::create(this))
, m_sweeper(IncrementalSweeper::create(this))
, m_deferralDepth(0)
{
m_storageSpace.init();
}
Heap::~Heap()
{
}
bool Heap::isPagedOut(double deadline)
{
return m_objectSpace.isPagedOut(deadline) || m_storageSpace.isPagedOut(deadline);
}
// The VM is being destroyed and the collector will never run again.
// Run all pending finalizers now because we won't get another chance.
void Heap::lastChanceToFinalize()
{
RELEASE_ASSERT(!m_vm->entryScope);
RELEASE_ASSERT(m_operationInProgress == NoOperation);
m_objectSpace.lastChanceToFinalize();
}
void Heap::reportExtraMemoryCostSlowCase(size_t cost)
{
// Our frequency of garbage collection tries to balance memory use against speed
// by collecting based on the number of newly created values. However, for values
// that hold on to a great deal of memory that's not in the form of other JS values,
// that is not good enough - in some cases a lot of those objects can pile up and
// use crazy amounts of memory without a GC happening. So we track these extra
// memory costs. Only unusually large objects are noted, and we only keep track
// of this extra cost until the next GC. In garbage collected languages, most values
// are either very short lived temporaries, or have extremely long lifetimes. So
// if a large value survives one garbage collection, there is not much point to
// collecting more frequently as long as it stays alive.
didAllocate(cost);
collectIfNecessaryOrDefer();
}
void Heap::reportAbandonedObjectGraph()
{
// Our clients don't know exactly how much memory they
// are abandoning so we just guess for them.
double abandonedBytes = 0.10 * m_sizeAfterLastCollect;
// We want to accelerate the next collection. Because memory has just
// been abandoned, the next collection has the potential to
// be more profitable. Since allocation is the trigger for collection,
// we hasten the next collection by pretending that we've allocated more memory.
didAbandon(abandonedBytes);
}
void Heap::didAbandon(size_t bytes)
{
if (m_activityCallback)
m_activityCallback->didAllocate(m_bytesAllocatedThisCycle + m_bytesAbandonedThisCycle);
m_bytesAbandonedThisCycle += bytes;
}
void Heap::protect(JSValue k)
{
ASSERT(k);
ASSERT(m_vm->currentThreadIsHoldingAPILock());
if (!k.isCell())
return;
m_protectedValues.add(k.asCell());
}
bool Heap::unprotect(JSValue k)
{
ASSERT(k);
ASSERT(m_vm->currentThreadIsHoldingAPILock());
if (!k.isCell())
return false;
return m_protectedValues.remove(k.asCell());
}
void Heap::addReference(JSCell* cell, ArrayBuffer* buffer)
{
if (m_arrayBuffers.addReference(cell, buffer)) {
collectIfNecessaryOrDefer();
didAllocate(buffer->gcSizeEstimateInBytes());
}
}
void Heap::markProtectedObjects(HeapRootVisitor& heapRootVisitor)
{
ProtectCountSet::iterator end = m_protectedValues.end();
for (ProtectCountSet::iterator it = m_protectedValues.begin(); it != end; ++it)
heapRootVisitor.visit(&it->key);
}
void Heap::pushTempSortVector(Vector<ValueStringPair, 0, UnsafeVectorOverflow>* tempVector)
{
m_tempSortingVectors.append(tempVector);
}
void Heap::popTempSortVector(Vector<ValueStringPair, 0, UnsafeVectorOverflow>* tempVector)
{
ASSERT_UNUSED(tempVector, tempVector == m_tempSortingVectors.last());
m_tempSortingVectors.removeLast();
}
void Heap::markTempSortVectors(HeapRootVisitor& heapRootVisitor)
{
typedef Vector<Vector<ValueStringPair, 0, UnsafeVectorOverflow>* > VectorOfValueStringVectors;
VectorOfValueStringVectors::iterator end = m_tempSortingVectors.end();
for (VectorOfValueStringVectors::iterator it = m_tempSortingVectors.begin(); it != end; ++it) {
Vector<ValueStringPair, 0, UnsafeVectorOverflow>* tempSortingVector = *it;
Vector<ValueStringPair>::iterator vectorEnd = tempSortingVector->end();
for (Vector<ValueStringPair>::iterator vectorIt = tempSortingVector->begin(); vectorIt != vectorEnd; ++vectorIt) {
if (vectorIt->first)
heapRootVisitor.visit(&vectorIt->first);
}
}
}
void Heap::harvestWeakReferences()
{
m_slotVisitor.harvestWeakReferences();
}
void Heap::finalizeUnconditionalFinalizers()
{
m_slotVisitor.finalizeUnconditionalFinalizers();
}
inline JSStack& Heap::stack()
{
return m_vm->interpreter->stack();
}
void Heap::willStartIterating()
{
m_objectSpace.willStartIterating();
}
void Heap::didFinishIterating()
{
m_objectSpace.didFinishIterating();
}
void Heap::getConservativeRegisterRoots(HashSet<JSCell*>& roots)
{
ASSERT(isValidThreadState(m_vm));
ConservativeRoots stackRoots(&m_objectSpace.blocks(), &m_storageSpace);
stack().gatherConservativeRoots(stackRoots);
size_t stackRootCount = stackRoots.size();
JSCell** registerRoots = stackRoots.roots();
for (size_t i = 0; i < stackRootCount; i++) {
setMarked(registerRoots[i]);
roots.add(registerRoots[i]);
}
}
void Heap::markRoots()
{
SamplingRegion samplingRegion("Garbage Collection: Tracing");
GCPHASE(MarkRoots);
ASSERT(isValidThreadState(m_vm));
#if ENABLE(OBJECT_MARK_LOGGING)
double gcStartTime = WTF::monotonicallyIncreasingTime();
#endif
void* dummy;
// We gather conservative roots before clearing mark bits because conservative
// gathering uses the mark bits to determine whether a reference is valid.
ConservativeRoots machineThreadRoots(&m_objectSpace.blocks(), &m_storageSpace);
m_jitStubRoutines.clearMarks();
{
GCPHASE(GatherConservativeRoots);
m_machineThreads.gatherConservativeRoots(machineThreadRoots, &dummy);
}
ConservativeRoots stackRoots(&m_objectSpace.blocks(), &m_storageSpace);
m_codeBlocks.clearMarks();
{
GCPHASE(GatherStackRoots);
stack().gatherConservativeRoots(stackRoots, m_jitStubRoutines, m_codeBlocks);
stack().sanitizeStack();
}
#if ENABLE(DFG_JIT)
ConservativeRoots scratchBufferRoots(&m_objectSpace.blocks(), &m_storageSpace);
{
GCPHASE(GatherScratchBufferRoots);
m_vm->gatherConservativeRoots(scratchBufferRoots);
}
#endif
{
GCPHASE(ClearLivenessData);
m_objectSpace.clearNewlyAllocated();
m_objectSpace.clearMarks();
}
m_sharedData.didStartMarking();
SlotVisitor& visitor = m_slotVisitor;
visitor.setup();
HeapRootVisitor heapRootVisitor(visitor);
#if ENABLE(GGC)
Vector<const JSCell*> rememberedSet(m_slotVisitor.markStack().size());
m_slotVisitor.markStack().fillVector(rememberedSet);
#endif
{
ParallelModeEnabler enabler(visitor);
m_vm->smallStrings.visitStrongReferences(visitor);
{
GCPHASE(VisitMachineRoots);
MARK_LOG_ROOT(visitor, "C++ Stack");
visitor.append(machineThreadRoots);
visitor.donateAndDrain();
}
{
GCPHASE(VisitStackRoots);
MARK_LOG_ROOT(visitor, "Stack");
visitor.append(stackRoots);
visitor.donateAndDrain();
}
#if ENABLE(DFG_JIT)
{
GCPHASE(VisitScratchBufferRoots);
MARK_LOG_ROOT(visitor, "Scratch Buffers");
visitor.append(scratchBufferRoots);
visitor.donateAndDrain();
}
#endif
{
GCPHASE(VisitProtectedObjects);
MARK_LOG_ROOT(visitor, "Protected Objects");
markProtectedObjects(heapRootVisitor);
visitor.donateAndDrain();
}
{
GCPHASE(VisitTempSortVectors);
MARK_LOG_ROOT(visitor, "Temp Sort Vectors");
markTempSortVectors(heapRootVisitor);
visitor.donateAndDrain();
}
{
GCPHASE(MarkingArgumentBuffers);
if (m_markListSet && m_markListSet->size()) {
MARK_LOG_ROOT(visitor, "Argument Buffers");
MarkedArgumentBuffer::markLists(heapRootVisitor, *m_markListSet);
visitor.donateAndDrain();
}
}
if (m_vm->exception()) {
GCPHASE(MarkingException);
MARK_LOG_ROOT(visitor, "Exceptions");
heapRootVisitor.visit(m_vm->addressOfException());
visitor.donateAndDrain();
}
{
GCPHASE(VisitStrongHandles);
MARK_LOG_ROOT(visitor, "Strong Handles");
m_handleSet.visitStrongHandles(heapRootVisitor);
visitor.donateAndDrain();
}
{
GCPHASE(HandleStack);
MARK_LOG_ROOT(visitor, "Handle Stack");
m_handleStack.visit(heapRootVisitor);
visitor.donateAndDrain();
}
{
GCPHASE(TraceCodeBlocksAndJITStubRoutines);
MARK_LOG_ROOT(visitor, "Trace Code Blocks and JIT Stub Routines");
m_codeBlocks.traceMarked(visitor);
m_jitStubRoutines.traceMarkedStubRoutines(visitor);
visitor.donateAndDrain();
}
#if ENABLE(PARALLEL_GC)
{
GCPHASE(Convergence);
visitor.drainFromShared(SlotVisitor::MasterDrain);
}
#endif
}
// Weak references must be marked last because their liveness depends on
// the liveness of the rest of the object graph.
{
GCPHASE(VisitingLiveWeakHandles);
MARK_LOG_ROOT(visitor, "Live Weak Handles");
while (true) {
m_objectSpace.visitWeakSets(heapRootVisitor);
harvestWeakReferences();
if (visitor.isEmpty())
break;
{
ParallelModeEnabler enabler(visitor);
visitor.donateAndDrain();
#if ENABLE(PARALLEL_GC)
visitor.drainFromShared(SlotVisitor::MasterDrain);
#endif
}
}
}
#if ENABLE(GGC)
{
GCPHASE(ClearRememberedSet);
for (unsigned i = 0; i < rememberedSet.size(); ++i) {
const JSCell* cell = rememberedSet[i];
MarkedBlock::blockFor(cell)->clearRemembered(cell);
}
}
#endif
GCCOUNTER(VisitedValueCount, visitor.visitCount());
m_sharedData.didFinishMarking();
#if ENABLE(OBJECT_MARK_LOGGING)
size_t visitCount = visitor.visitCount();
#if ENABLE(PARALLEL_GC)
visitCount += m_sharedData.childVisitCount();
#endif
MARK_LOG_MESSAGE2("\nNumber of live Objects after full GC %lu, took %.6f secs\n", visitCount, WTF::monotonicallyIncreasingTime() - gcStartTime);
#endif
if (m_operationInProgress == EdenCollection) {
m_totalBytesVisited += visitor.bytesVisited();
m_totalBytesCopied += visitor.bytesCopied();
} else {
ASSERT(m_operationInProgress == FullCollection);
m_totalBytesVisited = visitor.bytesVisited();
m_totalBytesCopied = visitor.bytesCopied();
}
#if ENABLE(PARALLEL_GC)
m_totalBytesVisited += m_sharedData.childBytesVisited();
m_totalBytesCopied += m_sharedData.childBytesCopied();
#endif
visitor.reset();
#if ENABLE(PARALLEL_GC)
m_sharedData.resetChildren();
#endif
m_sharedData.reset();
}
template <HeapOperation collectionType>
void Heap::copyBackingStores()
{
m_storageSpace.startedCopying<collectionType>();
if (m_storageSpace.shouldDoCopyPhase()) {
m_sharedData.didStartCopying();
m_copyVisitor.startCopying();
m_copyVisitor.copyFromShared();
m_copyVisitor.doneCopying();
// We need to wait for everybody to finish and return their CopiedBlocks
// before signaling that the phase is complete.
m_storageSpace.doneCopying();
m_sharedData.didFinishCopying();
} else
m_storageSpace.doneCopying();
}
size_t Heap::objectCount()
{
return m_objectSpace.objectCount();
}
size_t Heap::extraSize()
{
return m_extraMemoryUsage + m_arrayBuffers.size();
}
size_t Heap::size()
{
return m_objectSpace.size() + m_storageSpace.size() + extraSize();
}
size_t Heap::capacity()
{
return m_objectSpace.capacity() + m_storageSpace.capacity() + extraSize();
}
size_t Heap::sizeAfterCollect()
{
// The result here may not agree with the normal Heap::size().
// This is due to the fact that we only count live copied bytes
// rather than all used (including dead) copied bytes, thus it's
// always the case that m_totalBytesCopied <= m_storageSpace.size().
ASSERT(m_totalBytesCopied <= m_storageSpace.size());
return m_totalBytesVisited + m_totalBytesCopied + extraSize();
}
size_t Heap::protectedGlobalObjectCount()
{
return forEachProtectedCell<CountIfGlobalObject>();
}
size_t Heap::globalObjectCount()
{
HeapIterationScope iterationScope(*this);
return m_objectSpace.forEachLiveCell<CountIfGlobalObject>(iterationScope);
}
size_t Heap::protectedObjectCount()
{
return forEachProtectedCell<Count>();
}
PassOwnPtr<TypeCountSet> Heap::protectedObjectTypeCounts()
{
return forEachProtectedCell<RecordType>();
}
PassOwnPtr<TypeCountSet> Heap::objectTypeCounts()
{
HeapIterationScope iterationScope(*this);
return m_objectSpace.forEachLiveCell<RecordType>(iterationScope);
}
void Heap::deleteAllCompiledCode()
{
// If JavaScript is running, it's not safe to delete code, since we'll end
// up deleting code that is live on the stack.
if (m_vm->entryScope)
return;
for (ExecutableBase* current = m_compiledCode.head(); current; current = current->next()) {
if (!current->isFunctionExecutable())
continue;
static_cast<FunctionExecutable*>(current)->clearCodeIfNotCompiling();
}
m_codeBlocks.clearMarks();
m_codeBlocks.deleteUnmarkedAndUnreferenced();
}
void Heap::deleteUnmarkedCompiledCode()
{
ExecutableBase* next;
for (ExecutableBase* current = m_compiledCode.head(); current; current = next) {
next = current->next();
if (isMarked(current))
continue;
// We do this because executable memory is limited on some platforms and because
// CodeBlock requires eager finalization.
ExecutableBase::clearCodeVirtual(current);
m_compiledCode.remove(current);
}
m_codeBlocks.deleteUnmarkedAndUnreferenced();
m_jitStubRoutines.deleteUnmarkedJettisonedStubRoutines();
}
void Heap::addToRememberedSet(const JSCell* cell)
{
ASSERT(cell);
ASSERT(!Options::enableConcurrentJIT() || !isCompilationThread());
if (isInRememberedSet(cell))
return;
MarkedBlock::blockFor(cell)->setRemembered(cell);
m_slotVisitor.unconditionallyAppend(const_cast<JSCell*>(cell));
}
void Heap::collectAllGarbage()
{
if (!m_isSafeToCollect)
return;
m_shouldDoFullCollection = true;
collect();
SamplingRegion samplingRegion("Garbage Collection: Sweeping");
DelayedReleaseScope delayedReleaseScope(m_objectSpace);
m_objectSpace.sweep();
m_objectSpace.shrink();
}
static double minute = 60.0;
void Heap::collect()
{
#if ENABLE(ALLOCATION_LOGGING)
dataLogF("JSC GC starting collection.\n");
#endif
double before = 0;
if (Options::logGC()) {
dataLog("[GC: ");
before = currentTimeMS();
}
SamplingRegion samplingRegion("Garbage Collection");
RELEASE_ASSERT(!m_deferralDepth);
GCPHASE(Collect);
ASSERT(vm()->currentThreadIsHoldingAPILock());
RELEASE_ASSERT(vm()->identifierTable == wtfThreadData().currentIdentifierTable());
ASSERT(m_isSafeToCollect);
JAVASCRIPTCORE_GC_BEGIN();
RELEASE_ASSERT(m_operationInProgress == NoOperation);
{
RecursiveAllocationScope scope(*this);
m_vm->prepareToDiscardCode();
}
bool isFullCollection = m_shouldDoFullCollection;
if (isFullCollection) {
m_operationInProgress = FullCollection;
m_slotVisitor.clearMarkStack();
m_shouldDoFullCollection = false;
if (Options::logGC())
dataLog("FullCollection, ");
} else {
#if ENABLE(GGC)
m_operationInProgress = EdenCollection;
if (Options::logGC())
dataLog("EdenCollection, ");
#else
m_operationInProgress = FullCollection;
m_slotVisitor.clearMarkStack();
if (Options::logGC())
dataLog("FullCollection, ");
#endif
}
if (m_operationInProgress == FullCollection)
m_extraMemoryUsage = 0;
if (m_activityCallback)
m_activityCallback->willCollect();
double lastGCStartTime = WTF::monotonicallyIncreasingTime();
if (lastGCStartTime - m_lastCodeDiscardTime > minute) {
deleteAllCompiledCode();
m_lastCodeDiscardTime = WTF::monotonicallyIncreasingTime();
}
{
GCPHASE(StopAllocation);
m_objectSpace.stopAllocating();
if (m_operationInProgress == FullCollection)
m_storageSpace.didStartFullCollection();
}
{
GCPHASE(FlushWriteBarrierBuffer);
if (m_operationInProgress == EdenCollection)
m_writeBarrierBuffer.flush(*this);
else
m_writeBarrierBuffer.reset();
}
markRoots();
{
GCPHASE(ReapingWeakHandles);
m_objectSpace.reapWeakSets();
}
JAVASCRIPTCORE_GC_MARKED();
{
GCPHASE(SweepingArrayBuffers);
m_arrayBuffers.sweep();
}
if (m_operationInProgress == FullCollection) {
m_blockSnapshot.resize(m_objectSpace.blocks().set().size());
MarkedBlockSnapshotFunctor functor(m_blockSnapshot);
m_objectSpace.forEachBlock(functor);
}
if (m_operationInProgress == FullCollection)
copyBackingStores<FullCollection>();
else
copyBackingStores<EdenCollection>();
{
GCPHASE(FinalizeUnconditionalFinalizers);
finalizeUnconditionalFinalizers();
}
{
GCPHASE(DeleteCodeBlocks);
deleteUnmarkedCompiledCode();
}
{
GCPHASE(DeleteSourceProviderCaches);
m_vm->clearSourceProviderCaches();
}
if (m_operationInProgress == FullCollection)
m_sweeper->startSweeping(m_blockSnapshot);
{
GCPHASE(AddCurrentlyExecutingCodeBlocksToRememberedSet);
m_codeBlocks.rememberCurrentlyExecutingCodeBlocks(this);
}
m_bytesAbandonedThisCycle = 0;
{
GCPHASE(ResetAllocators);
m_objectSpace.resetAllocators();
}
size_t currentHeapSize = sizeAfterCollect();
if (Options::gcMaxHeapSize() && currentHeapSize > Options::gcMaxHeapSize())
HeapStatistics::exitWithFailure();
if (m_operationInProgress == FullCollection) {
// To avoid pathological GC churn in very small and very large heaps, we set
// the new allocation limit based on the current size of the heap, with a
// fixed minimum.
m_maxHeapSize = max(minHeapSize(m_heapType, m_ramSize), proportionalHeapSize(currentHeapSize, m_ramSize));
m_maxEdenSize = m_maxHeapSize - currentHeapSize;
} else {
ASSERT(currentHeapSize >= m_sizeAfterLastCollect);
m_maxEdenSize = m_maxHeapSize - currentHeapSize;
double edenToOldGenerationRatio = (double)m_maxEdenSize / (double)m_maxHeapSize;
double minEdenToOldGenerationRatio = 1.0 / 3.0;
if (edenToOldGenerationRatio < minEdenToOldGenerationRatio)
m_shouldDoFullCollection = true;
m_maxHeapSize += currentHeapSize - m_sizeAfterLastCollect;
m_maxEdenSize = m_maxHeapSize - currentHeapSize;
}
m_sizeAfterLastCollect = currentHeapSize;
m_bytesAllocatedThisCycle = 0;
double lastGCEndTime = WTF::monotonicallyIncreasingTime();
m_lastGCLength = lastGCEndTime - lastGCStartTime;
if (Options::recordGCPauseTimes())
HeapStatistics::recordGCPauseTime(lastGCStartTime, lastGCEndTime);
RELEASE_ASSERT(m_operationInProgress == EdenCollection || m_operationInProgress == FullCollection);
m_operationInProgress = NoOperation;
JAVASCRIPTCORE_GC_END();
if (Options::useZombieMode())
zombifyDeadObjects();
if (Options::objectsAreImmortal())
markDeadObjects();
if (Options::showObjectStatistics())
HeapStatistics::showObjectStatistics(this);
if (Options::logGC()) {
double after = currentTimeMS();
dataLog(after - before, " ms, ", currentHeapSize / 1024, " kb]\n");
}
}
bool Heap::collectIfNecessaryOrDefer()
{
if (m_deferralDepth)
return false;
if (!shouldCollect())
return false;
collect();
return true;
}
void Heap::markDeadObjects()
{
HeapIterationScope iterationScope(*this);
m_objectSpace.forEachDeadCell<MarkObject>(iterationScope);
}
void Heap::setActivityCallback(PassOwnPtr<GCActivityCallback> activityCallback)
{
m_activityCallback = activityCallback;
}
GCActivityCallback* Heap::activityCallback()
{
return m_activityCallback.get();
}
void Heap::setIncrementalSweeper(PassOwnPtr<IncrementalSweeper> sweeper)
{
m_sweeper = sweeper;
}
IncrementalSweeper* Heap::sweeper()
{
return m_sweeper.get();
}
void Heap::setGarbageCollectionTimerEnabled(bool enable)
{
if (m_activityCallback)
m_activityCallback->setEnabled(enable);
}
void Heap::didAllocate(size_t bytes)
{
if (m_activityCallback)
m_activityCallback->didAllocate(m_bytesAllocatedThisCycle + m_bytesAbandonedThisCycle);