runtime/VM.h

   1 /*
   2  * Copyright (C) 2008, 2009, 2013, 2014 Apple Inc. All rights reserved.
   3  *
   4  * Redistribution and use in source and binary forms, with or without
   5  * modification, are permitted provided that the following conditions
   6  * are met:
   7  *
   8  * 1.  Redistributions of source code must retain the above copyright
   9  *     notice, this list of conditions and the following disclaimer.
  10  * 2.  Redistributions in binary form must reproduce the above copyright
  11  *     notice, this list of conditions and the following disclaimer in the
  12  *     documentation and/or other materials provided with the distribution.
  13  * 3.  Neither the name of Apple Inc. ("Apple") nor the names of
  14  *     its contributors may be used to endorse or promote products derived
  15  *     from this software without specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
  18  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
  19  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  20  * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
  21  * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
  22  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  23  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
  24  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  25  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  26  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  27  */
  28
  29 #ifndef VM_h
  30 #define VM_h
  31
  32 #include "DateInstanceCache.h"
  33 #include "ExecutableAllocator.h"
  34 #include "Heap.h"
  35 #include "Intrinsic.h"
  36 #include "JITThunks.h"
  37 #include "JSCJSValue.h"
  38 #include "JSLock.h"
  39 #include "LLIntData.h"
  40 #include "MacroAssemblerCodeRef.h"
  41 #include "NumericStrings.h"
  42 #include "PrivateName.h"
  43 #include "PrototypeMap.h"
  44 #include "SmallStrings.h"
  45 #include "SourceCode.h"
  46 #include "Strong.h"
  47 #include "ThunkGenerators.h"
  48 #include "TypedArrayController.h"
  49 #include "Watchdog.h"
  50 #include "Watchpoint.h"
  51 #include "WeakRandom.h"
  52 #include <wtf/BumpPointerAllocator.h>
  53 #include <wtf/DateMath.h>
  54 #include <wtf/Forward.h>
  55 #include <wtf/HashMap.h>
  56 #include <wtf/HashSet.h>
  57 #include <wtf/RefCountedArray.h>
  58 #include <wtf/SimpleStats.h>
  59 #include <wtf/StackBounds.h>
  60 #include <wtf/ThreadSafeRefCounted.h>
  61 #include <wtf/ThreadSpecific.h>
  62 #include <wtf/WTFThreadData.h>
  63 #include <wtf/text/WTFString.h>
  64 #if ENABLE(REGEXP_TRACING)
  65 #include <wtf/ListHashSet.h>
  66 #endif
  67
  68 namespace JSC {
  69
  70     class ArityCheckFailReturnThunks;
  71     class BuiltinExecutables;
  72     class CodeBlock;
  73     class CodeCache;
  74     class CommonIdentifiers;
  75     class ExecState;
  76     class HandleStack;
  77     class Identifier;
  78     class Interpreter;
  79     class JSGlobalObject;
  80     class JSObject;
  81     class Keywords;
  82     class LLIntOffsetsExtractor;
  83     class LegacyProfiler;
  84     class NativeExecutable;
  85     class ParserArena;
  86     class RegExpCache;
  87     class SourceProvider;
  88     class SourceProviderCache;
  89     struct StackFrame;
  90     class Stringifier;
  91     class Structure;
  92 #if ENABLE(REGEXP_TRACING)
  93     class RegExp;
  94 #endif
  95     class UnlinkedCodeBlock;
  96     class UnlinkedEvalCodeBlock;
  97     class UnlinkedFunctionExecutable;
  98     class UnlinkedProgramCodeBlock;
  99     class VMEntryScope;
 100     class Watchpoint;
 101     class WatchpointSet;
 102
 103 #if ENABLE(DFG_JIT)
 104     namespace DFG {
 105     class LongLivedState;
 106     }
 107 #endif // ENABLE(DFG_JIT)
 108 #if ENABLE(FTL_JIT)
 109     namespace FTL {
 110     class Thunks;
 111     }
 112 #endif // ENABLE(FTL_JIT)
 113     namespace CommonSlowPaths {
 114     struct ArityCheckData;
 115     }
 116     namespace Profiler {
 117     class Database;
 118     }
 119
 120     struct HashTable;
 121     struct Instruction;
 122
 123     struct LocalTimeOffsetCache {
 124         LocalTimeOffsetCache()
 125             : start(0.0)
 126             , end(-1.0)
 127             , increment(0.0)
 128         {
 129         }
 130
 131         void reset()
 132         {
 133             offset = LocalTimeOffset();
 134             start = 0.0;
 135             end = -1.0;
 136             increment = 0.0;
 137         }
 138
 139         LocalTimeOffset offset;
 140         double start;
 141         double end;
 142         double increment;
 143     };
 144
 145     class ConservativeRoots;
 146
 147 #if COMPILER(MSVC)
 148 #pragma warning(push)
 149 #pragma warning(disable: 4200) // Disable "zero-sized array in struct/union" warning
 150 #endif
 151     struct ScratchBuffer {
 152         ScratchBuffer()
 153         {
 154             u.m_activeLength = 0;
 155         }
 156
 157         static ScratchBuffer* create(size_t size)
 158         {
 159             ScratchBuffer* result = new (fastMalloc(ScratchBuffer::allocationSize(size))) ScratchBuffer;
 160
 161             return result;
 162         }
 163
 164         static size_t allocationSize(size_t bufferSize) { return sizeof(ScratchBuffer) + bufferSize; }
 165         void setActiveLength(size_t activeLength) { u.m_activeLength = activeLength; }
 166         size_t activeLength() const { return u.m_activeLength; };
 167         size_t* activeLengthPtr() { return &u.m_activeLength; };
 168         void* dataBuffer() { return m_buffer; }
 169
 170         union {
 171             size_t m_activeLength;
 172             double pad; // Make sure m_buffer is double aligned.
 173         } u;
 174 #if CPU(MIPS) && (defined WTF_MIPS_ARCH_REV && WTF_MIPS_ARCH_REV == 2)
 175         void* m_buffer[0] __attribute__((aligned(8)));
 176 #else
 177         void* m_buffer[0];
 178 #endif
 179     };
 180 #if COMPILER(MSVC)
 181 #pragma warning(pop)
 182 #endif
 183
 184     class VM : public ThreadSafeRefCounted<VM> {
 185     public:
 186         // WebCore has a one-to-one mapping of threads to VMs;
 187         // either create() or createLeaked() should only be called once
 188         // on a thread, this is the 'default' VM (it uses the
 189         // thread's default string uniquing table from wtfThreadData).
 190         // API contexts created using the new context group aware interface
 191         // create APIContextGroup objects which require less locking of JSC
 192         // than the old singleton APIShared VM created for use by
 193         // the original API.
 194         enum VMType { Default, APIContextGroup, APIShared };
 195
 196         struct ClientData {
 197             JS_EXPORT_PRIVATE virtual ~ClientData() = 0;
 198         };
 199
 200         bool isSharedInstance() { return vmType == APIShared; }
 201         bool usingAPI() { return vmType != Default; }
 202         JS_EXPORT_PRIVATE static bool sharedInstanceExists();
 203         JS_EXPORT_PRIVATE static VM& sharedInstance();
 204
 205         JS_EXPORT_PRIVATE static PassRefPtr<VM> create(HeapType = SmallHeap);
 206         JS_EXPORT_PRIVATE static PassRefPtr<VM> createLeaked(HeapType = SmallHeap);
 207         static PassRefPtr<VM> createContextGroup(HeapType = SmallHeap);
 208         JS_EXPORT_PRIVATE ~VM();
 209
 210         void makeUsableFromMultipleThreads() { heap.machineThreads().makeUsableFromMultipleThreads(); }
 211
 212     private:
 213         RefPtr<JSLock> m_apiLock;
 214
 215     public:
 216 #if ENABLE(ASSEMBLER)
 217         // executableAllocator should be destructed after the heap, as the heap can call executableAllocator
 218         // in its destructor.
 219         ExecutableAllocator executableAllocator;
 220 #endif
 221
 222         // The heap should be just after executableAllocator and before other members to ensure that it's
 223         // destructed after all the objects that reference it.
 224         Heap heap;
 225
 226 #if ENABLE(DFG_JIT)
 227         OwnPtr<DFG::LongLivedState> dfgState;
 228 #endif // ENABLE(DFG_JIT)
 229
 230         VMType vmType;
 231         ClientData* clientData;
 232         ExecState* topCallFrame;
 233         std::unique_ptr<Watchdog> watchdog;
 234
 235         const OwnPtr<const HashTable> arrayConstructorTable;
 236         const OwnPtr<const HashTable> arrayPrototypeTable;
 237         const OwnPtr<const HashTable> booleanPrototypeTable;
 238         const OwnPtr<const HashTable> dataViewTable;
 239         const OwnPtr<const HashTable> dateTable;
 240         const OwnPtr<const HashTable> dateConstructorTable;
 241         const OwnPtr<const HashTable> errorPrototypeTable;
 242         const OwnPtr<const HashTable> globalObjectTable;
 243         const OwnPtr<const HashTable> jsonTable;
 244         const OwnPtr<const HashTable> numberConstructorTable;
 245         const OwnPtr<const HashTable> numberPrototypeTable;
 246         const OwnPtr<const HashTable> objectConstructorTable;
 247         const OwnPtr<const HashTable> privateNamePrototypeTable;
 248         const OwnPtr<const HashTable> regExpTable;
 249         const OwnPtr<const HashTable> regExpConstructorTable;
 250         const OwnPtr<const HashTable> regExpPrototypeTable;
 251         const OwnPtr<const HashTable> stringConstructorTable;
 252 #if ENABLE(PROMISES)
 253         const OwnPtr<const HashTable> promisePrototypeTable;
 254         const OwnPtr<const HashTable> promiseConstructorTable;
 255 #endif
 256
 257         Strong<Structure> structureStructure;
 258         Strong<Structure> structureRareDataStructure;
 259         Strong<Structure> debuggerActivationStructure;
 260         Strong<Structure> terminatedExecutionErrorStructure;
 261         Strong<Structure> stringStructure;
 262         Strong<Structure> notAnObjectStructure;
 263         Strong<Structure> propertyNameIteratorStructure;
 264         Strong<Structure> getterSetterStructure;
 265         Strong<Structure> customGetterSetterStructure;
 266         Strong<Structure> apiWrapperStructure;
 267         Strong<Structure> JSScopeStructure;
 268         Strong<Structure> executableStructure;
 269         Strong<Structure> nativeExecutableStructure;
 270         Strong<Structure> evalExecutableStructure;
 271         Strong<Structure> programExecutableStructure;
 272         Strong<Structure> functionExecutableStructure;
 273         Strong<Structure> regExpStructure;
 274         Strong<Structure> symbolTableStructure;
 275         Strong<Structure> structureChainStructure;
 276         Strong<Structure> sparseArrayValueMapStructure;
 277         Strong<Structure> arrayBufferNeuteringWatchpointStructure;
 278         Strong<Structure> withScopeStructure;
 279         Strong<Structure> unlinkedFunctionExecutableStructure;
 280         Strong<Structure> unlinkedProgramCodeBlockStructure;
 281         Strong<Structure> unlinkedEvalCodeBlockStructure;
 282         Strong<Structure> unlinkedFunctionCodeBlockStructure;
 283         Strong<Structure> propertyTableStructure;
 284         Strong<Structure> mapDataStructure;
 285         Strong<Structure> weakMapDataStructure;
 286 #if ENABLE(PROMISES)
 287         Strong<Structure> promiseDeferredStructure;
 288         Strong<Structure> promiseReactionStructure;
 289 #endif
 290         Strong<JSCell> iterationTerminator;
 291
 292         AtomicStringTable* m_atomicStringTable;
 293         CommonIdentifiers* propertyNames;
 294         const MarkedArgumentBuffer* emptyList; // Lists are supposed to be allocated on the stack to have their elements properly marked, which is not the case here - but this list has nothing to mark.
 295         SmallStrings smallStrings;
 296         NumericStrings numericStrings;
 297         DateInstanceCache dateInstanceCache;
 298         WTF::SimpleStats machineCodeBytesPerBytecodeWordForBaselineJIT;
 299         WeakGCMap<StringImpl*, JSString, PtrHash<StringImpl*>> stringCache;
 300         Strong<JSString> lastCachedString;
 301
 302         AtomicStringTable* atomicStringTable() const { return m_atomicStringTable; }
 303
 304         void setInDefineOwnProperty(bool inDefineOwnProperty)
 305         {
 306             m_inDefineOwnProperty = inDefineOwnProperty;
 307         }
 308
 309         bool isInDefineOwnProperty()
 310         {
 311             return m_inDefineOwnProperty;
 312         }
 313
 314         LegacyProfiler* enabledProfiler() { return m_enabledProfiler; }
 315         void setEnabledProfiler(LegacyProfiler*);
 316
 317         void* enabledProfilerAddress() { return &m_enabledProfiler; }
 318
 319 #if ENABLE(JIT)
 320         bool canUseJIT() { return m_canUseJIT; }
 321 #else
 322         bool canUseJIT() { return false; } // interpreter only
 323 #endif
 324
 325 #if ENABLE(YARR_JIT)
 326         bool canUseRegExpJIT() { return m_canUseRegExpJIT; }
 327 #else
 328         bool canUseRegExpJIT() { return false; } // interpreter only
 329 #endif
 330
 331         SourceProviderCache* addSourceProviderCache(SourceProvider*);
 332         void clearSourceProviderCaches();
 333
 334         PrototypeMap prototypeMap;
 335
 336         OwnPtr<ParserArena> parserArena;
 337         typedef HashMap<RefPtr<SourceProvider>, RefPtr<SourceProviderCache>> SourceProviderCacheMap;
 338         SourceProviderCacheMap sourceProviderCacheMap;
 339         OwnPtr<Keywords> keywords;
 340         Interpreter* interpreter;
 341 #if ENABLE(JIT)
 342         OwnPtr<JITThunks> jitStubs;
 343         MacroAssemblerCodeRef getCTIStub(ThunkGenerator generator)
 344         {
 345             return jitStubs->ctiStub(this, generator);
 346         }
 347         NativeExecutable* getHostFunction(NativeFunction, Intrinsic);
 348
 349         std::unique_ptr<ArityCheckFailReturnThunks> arityCheckFailReturnThunks;
 350 #endif // ENABLE(JIT)
 351         std::unique_ptr<CommonSlowPaths::ArityCheckData> arityCheckData;
 352 #if ENABLE(FTL_JIT)
 353         std::unique_ptr<FTL::Thunks> ftlThunks;
 354 #endif
 355         NativeExecutable* getHostFunction(NativeFunction, NativeFunction constructor);
 356
 357         static ptrdiff_t exceptionOffset()
 358         {
 359             return OBJECT_OFFSETOF(VM, m_exception);
 360         }
 361
 362         static ptrdiff_t callFrameForThrowOffset()
 363         {
 364             return OBJECT_OFFSETOF(VM, callFrameForThrow);
 365         }
 366
 367         static ptrdiff_t targetMachinePCForThrowOffset()
 368         {
 369             return OBJECT_OFFSETOF(VM, targetMachinePCForThrow);
 370         }
 371
 372         JS_EXPORT_PRIVATE void clearException();
 373         JS_EXPORT_PRIVATE void clearExceptionStack();
 374         void getExceptionInfo(JSValue& exception, RefCountedArray<StackFrame>& exceptionStack);
 375         void setExceptionInfo(JSValue& exception, RefCountedArray<StackFrame>& exceptionStack);
 376         JSValue exception() const { return m_exception; }
 377         JSValue* addressOfException() { return &m_exception; }
 378         const RefCountedArray<StackFrame>& exceptionStack() const { return m_exceptionStack; }
 379
 380         JS_EXPORT_PRIVATE JSValue throwException(ExecState*, JSValue);
 381         JS_EXPORT_PRIVATE JSObject* throwException(ExecState*, JSObject*);
 382
 383         void* stackPointerAtVMEntry() const { return m_stackPointerAtVMEntry; }
 384         void setStackPointerAtVMEntry(void*);
 385
 386         size_t reservedZoneSize() const { return m_reservedZoneSize; }
 387         size_t updateReservedZoneSize(size_t reservedZoneSize);
 388
 389 #if ENABLE(FTL_JIT)
 390         void updateFTLLargestStackSize(size_t);
 391         void** addressOfFTLStackLimit() { return &m_ftlStackLimit; }
 392 #endif
 393
 394 #if !ENABLE(JIT)
 395         void* jsStackLimit() { return m_jsStackLimit; }
 396         void setJSStackLimit(void* limit) { m_jsStackLimit = limit; }
 397 #endif
 398         void* stackLimit() { return m_stackLimit; }
 399         void** addressOfStackLimit() { return &m_stackLimit; }
 400
 401         bool isSafeToRecurse(size_t neededStackInBytes = 0) const
 402         {
 403             ASSERT(wtfThreadData().stack().isGrowingDownward());
 404             int8_t* curr = reinterpret_cast<int8_t*>(&curr);
 405             int8_t* limit = reinterpret_cast<int8_t*>(m_stackLimit);
 406             return curr >= limit && static_cast<size_t>(curr - limit) >= neededStackInBytes;
 407         }
 408
 409         void* lastStackTop() { return m_lastStackTop; }
 410         void setLastStackTop(void* lastStackTop) { m_lastStackTop = lastStackTop; }
 411
 412         const ClassInfo* const jsArrayClassInfo;
 413         const ClassInfo* const jsFinalObjectClassInfo;
 414
 415         JSValue hostCallReturnValue;
 416         ExecState* newCallFrameReturnValue;
 417         unsigned varargsLength;
 418         ExecState* callFrameForThrow;
 419         void* targetMachinePCForThrow;
 420         Instruction* targetInterpreterPCForThrow;
 421         uint32_t osrExitIndex;
 422         void* osrExitJumpDestination;
 423         Vector<ScratchBuffer*> scratchBuffers;
 424         size_t sizeOfLastScratchBuffer;
 425
 426         ScratchBuffer* scratchBufferForSize(size_t size)
 427         {
 428             if (!size)
 429                 return 0;
 430
 431             if (size > sizeOfLastScratchBuffer) {
 432                 // Protect against a N^2 memory usage pathology by ensuring
 433                 // that at worst, we get a geometric series, meaning that the
 434                 // total memory usage is somewhere around
 435                 // max(scratch buffer size) * 4.
 436                 sizeOfLastScratchBuffer = size * 2;
 437
 438                 ScratchBuffer* newBuffer = ScratchBuffer::create(sizeOfLastScratchBuffer);
 439                 RELEASE_ASSERT(newBuffer);
 440                 scratchBuffers.append(newBuffer);
 441             }
 442
 443             ScratchBuffer* result = scratchBuffers.last();
 444             result->setActiveLength(0);
 445             return result;
 446         }
 447
 448         void gatherConservativeRoots(ConservativeRoots&);
 449
 450         VMEntryScope* entryScope;
 451
 452         HashSet<JSObject*> stringRecursionCheckVisitedObjects;
 453
 454         LocalTimeOffsetCache localTimeOffsetCache;
 455
 456         String cachedDateString;
 457         double cachedDateStringValue;
 458
 459         OwnPtr<Profiler::Database> m_perBytecodeProfiler;
 460         RefPtr<TypedArrayController> m_typedArrayController;
 461         RegExpCache* m_regExpCache;
 462         BumpPointerAllocator m_regExpAllocator;
 463
 464 #if ENABLE(REGEXP_TRACING)
 465         typedef ListHashSet<RegExp*> RTTraceList;
 466         RTTraceList* m_rtTraceList;
 467 #endif
 468
 469         bool hasExclusiveThread() const { return m_apiLock->hasExclusiveThread(); }
 470         std::thread::id exclusiveThread() const { return m_apiLock->exclusiveThread(); }
 471         void setExclusiveThread(std::thread::id threadId) { m_apiLock->setExclusiveThread(threadId); }
 472
 473         JS_EXPORT_PRIVATE void resetDateCache();
 474
 475         JS_EXPORT_PRIVATE void startSampling();
 476         JS_EXPORT_PRIVATE void stopSampling();
 477         JS_EXPORT_PRIVATE void dumpSampleData(ExecState* exec);
 478         RegExpCache* regExpCache() { return m_regExpCache; }
 479 #if ENABLE(REGEXP_TRACING)
 480         void addRegExpToTrace(RegExp*);
 481 #endif
 482         JS_EXPORT_PRIVATE void dumpRegExpTrace();
 483
 484         bool isCollectorBusy() { return heap.isBusy(); }
 485         JS_EXPORT_PRIVATE void releaseExecutableMemory();
 486
 487 #if ENABLE(GC_VALIDATION)
 488         bool isInitializingObject() const;
 489         void setInitializingObjectClass(const ClassInfo*);
 490 #endif
 491
 492         unsigned m_newStringsSinceLastHashCons;
 493
 494         static const unsigned s_minNumberOfNewStringsToHashCons = 100;
 495
 496         bool haveEnoughNewStringsToHashCons() { return m_newStringsSinceLastHashCons > s_minNumberOfNewStringsToHashCons; }
 497         void resetNewStringsSinceLastHashCons() { m_newStringsSinceLastHashCons = 0; }
 498
 499         bool currentThreadIsHoldingAPILock() const { return m_apiLock->currentThreadIsHoldingLock(); }
 500
 501         JSLock& apiLock() { return *m_apiLock; }
 502         CodeCache* codeCache() { return m_codeCache.get(); }
 503
 504         void waitForCompilationsToComplete();
 505
 506         JS_EXPORT_PRIVATE void discardAllCode();
 507
 508         void registerWatchpointForImpureProperty(const Identifier&, Watchpoint*);
 509         // FIXME: Use AtomicString once it got merged with Identifier.
 510         JS_EXPORT_PRIVATE void addImpureProperty(const String&);
 511
 512         BuiltinExecutables* builtinExecutables() { return m_builtinExecutables.get(); }
 513
 514     private:
 515         friend class LLIntOffsetsExtractor;
 516         friend class ClearExceptionScope;
 517         friend class RecursiveAllocationScope;
 518
 519         VM(VMType, HeapType);
 520         static VM*& sharedInstanceInternal();
 521         void createNativeThunk();
 522
 523         void updateStackLimit();
 524
 525 #if ENABLE(ASSEMBLER)
 526         bool m_canUseAssembler;
 527 #endif
 528 #if ENABLE(JIT)
 529         bool m_canUseJIT;
 530 #endif
 531 #if ENABLE(YARR_JIT)
 532         bool m_canUseRegExpJIT;
 533 #endif
 534 #if ENABLE(GC_VALIDATION)
 535         const ClassInfo* m_initializingObjectClass;
 536 #endif
 537         void* m_stackPointerAtVMEntry;
 538         size_t m_reservedZoneSize;
 539 #if !ENABLE(JIT)
 540         struct {
 541             void* m_stackLimit;
 542             void* m_jsStackLimit;
 543         };
 544 #else
 545         union {
 546             void* m_stackLimit;
 547             void* m_jsStackLimit;
 548         };
 549 #if ENABLE(FTL_JIT)
 550         void* m_ftlStackLimit;
 551         size_t m_largestFTLStackSize;
 552 #endif
 553 #endif
 554         void* m_lastStackTop;
 555         JSValue m_exception;
 556         bool m_inDefineOwnProperty;
 557         OwnPtr<CodeCache> m_codeCache;
 558         LegacyProfiler* m_enabledProfiler;
 559         OwnPtr<BuiltinExecutables> m_builtinExecutables;
 560         RefCountedArray<StackFrame> m_exceptionStack;
 561         HashMap<String, RefPtr<WatchpointSet>> m_impurePropertyWatchpointSets;
 562     };
 563
 564 #if ENABLE(GC_VALIDATION)
 565     inline bool VM::isInitializingObject() const
 566     {
 567         return !!m_initializingObjectClass;
 568     }
 569
 570     inline void VM::setInitializingObjectClass(const ClassInfo* initializingObjectClass)
 571     {
 572         m_initializingObjectClass = initializingObjectClass;
 573     }
 574 #endif
 575
 576     inline Heap* WeakSet::heap() const
 577     {
 578         return &m_vm->heap;
 579     }
 580
 581 #if ENABLE(JIT)
 582     extern "C" void sanitizeStackForVMImpl(VM*);
 583 #endif
 584
 585     void sanitizeStackForVM(VM*);
 586     void logSanitizeStack(VM*);
 587
 588 } // namespace JSC
 589
 590 #endif // VM_h