1/*
2 * Copyright (C) 2012-2019 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 * 1. Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
14 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
16 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR
17 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
18 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
19 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
20 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
21 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
23 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24 */
25
26#pragma once
27
28#include "AllocatorForMode.h"
29#include "AllocatorInlines.h"
30#include "CompleteSubspaceInlines.h"
31#include "CPU.h"
32#include "CallFrameInlines.h"
33#include "DeferGC.h"
34#include "FreeListInlines.h"
35#include "Handle.h"
36#include "HeapInlines.h"
37#include "IsoSubspaceInlines.h"
38#include "JSBigInt.h"
39#include "JSCast.h"
40#include "JSDestructibleObject.h"
41#include "JSObject.h"
42#include "JSString.h"
43#include "LocalAllocatorInlines.h"
44#include "MarkedBlock.h"
45#include "SlotVisitorInlines.h"
46#include "Structure.h"
47#include "Symbol.h"
48#include <wtf/CompilationThread.h>
49
50namespace JSC {
51
52inline JSCell::JSCell(CreatingEarlyCellTag)
53 : m_cellState(CellState::DefinitelyWhite)
54{
55 ASSERT(!isCompilationThread());
56}
57
58inline JSCell::JSCell(VM&, Structure* structure)
59 : m_structureID(structure->id())
60 , m_indexingTypeAndMisc(structure->indexingModeIncludingHistory())
61 , m_type(structure->typeInfo().type())
62 , m_flags(structure->typeInfo().inlineTypeFlags())
63 , m_cellState(CellState::DefinitelyWhite)
64{
65 ASSERT(!isCompilationThread());
66}
67
68inline void JSCell::finishCreation(VM& vm)
69{
70 // This object is ready to be escaped so the concurrent GC may see it at any time. We have
71 // to make sure that none of our stores sink below here.
72 vm.heap.mutatorFence();
73#if ENABLE(GC_VALIDATION)
74 ASSERT(vm.isInitializingObject());
75 vm.setInitializingObjectClass(0);
76#else
77 UNUSED_PARAM(vm);
78#endif
79 ASSERT(m_structureID);
80}
81
82inline void JSCell::finishCreation(VM& vm, Structure* structure, CreatingEarlyCellTag)
83{
84#if ENABLE(GC_VALIDATION)
85 ASSERT(vm.isInitializingObject());
86 vm.setInitializingObjectClass(0);
87 if (structure) {
88#endif
89 m_structureID = structure->id();
90 m_indexingTypeAndMisc = structure->indexingModeIncludingHistory();
91 m_type = structure->typeInfo().type();
92 m_flags = structure->typeInfo().inlineTypeFlags();
93#if ENABLE(GC_VALIDATION)
94 }
95#else
96 UNUSED_PARAM(vm);
97#endif
98 // Very first set of allocations won't have a real structure.
99 ASSERT(m_structureID || !vm.structureStructure);
100}
101
102inline JSType JSCell::type() const
103{
104 return m_type;
105}
106
107inline IndexingType JSCell::indexingTypeAndMisc() const
108{
109 return m_indexingTypeAndMisc;
110}
111
112inline IndexingType JSCell::indexingType() const
113{
114 return indexingTypeAndMisc() & AllWritableArrayTypes;
115}
116
117inline IndexingType JSCell::indexingMode() const
118{
119 return indexingTypeAndMisc() & AllArrayTypes;
120}
121
122ALWAYS_INLINE Structure* JSCell::structure() const
123{
124 return structure(vm());
125}
126
127ALWAYS_INLINE Structure* JSCell::structure(VM& vm) const
128{
129 return vm.getStructure(m_structureID);
130}
131
132inline void JSCell::visitChildren(JSCell* cell, SlotVisitor& visitor)
133{
134 visitor.appendUnbarriered(cell->structure(visitor.vm()));
135}
136
137inline void JSCell::visitOutputConstraints(JSCell*, SlotVisitor&)
138{
139}
140
141ALWAYS_INLINE VM& CallFrame::deprecatedVM() const
142{
143 JSCell* callee = this->callee().asCell();
144 ASSERT(callee);
145 ASSERT(&callee->vm());
146 return callee->vm();
147}
148
149template<typename CellType, SubspaceAccess>
150CompleteSubspace* JSCell::subspaceFor(VM& vm)
151{
152 if (CellType::needsDestruction)
153 return &vm.destructibleCellSpace;
154 return &vm.cellSpace;
155}
156
157template<typename Type>
158inline Allocator allocatorForNonVirtualConcurrently(VM& vm, size_t allocationSize, AllocatorForMode mode)
159{
160 if (auto* subspace = subspaceForConcurrently<Type>(vm))
161 return subspace->allocatorForNonVirtual(allocationSize, mode);
162 return { };
163}
164
165template<typename T>
166ALWAYS_INLINE void* tryAllocateCellHelper(Heap& heap, size_t size, GCDeferralContext* deferralContext, AllocationFailureMode failureMode)
167{
168 VM& vm = heap.vm();
169 ASSERT(deferralContext || !DisallowGC::isInEffectOnCurrentThread());
170 ASSERT(size >= sizeof(T));
171 JSCell* result = static_cast<JSCell*>(subspaceFor<T>(vm)->allocateNonVirtual(vm, size, deferralContext, failureMode));
172 if (failureMode == AllocationFailureMode::ReturnNull && !result)
173 return nullptr;
174#if ENABLE(GC_VALIDATION)
175 ASSERT(!vm.isInitializingObject());
176 vm.setInitializingObjectClass(T::info());
177#endif
178 result->clearStructure();
179 return result;
180}
181
182template<typename T>
183void* allocateCell(Heap& heap, size_t size)
184{
185 return tryAllocateCellHelper<T>(heap, size, nullptr, AllocationFailureMode::Assert);
186}
187
188template<typename T>
189void* tryAllocateCell(Heap& heap, size_t size)
190{
191 return tryAllocateCellHelper<T>(heap, size, nullptr, AllocationFailureMode::ReturnNull);
192}
193
194template<typename T>
195void* allocateCell(Heap& heap, GCDeferralContext* deferralContext, size_t size)
196{
197 return tryAllocateCellHelper<T>(heap, size, deferralContext, AllocationFailureMode::Assert);
198}
199
200template<typename T>
201void* tryAllocateCell(Heap& heap, GCDeferralContext* deferralContext, size_t size)
202{
203 return tryAllocateCellHelper<T>(heap, size, deferralContext, AllocationFailureMode::ReturnNull);
204}
205
206inline bool JSCell::isObject() const
207{
208 return TypeInfo::isObject(m_type);
209}
210
211inline bool JSCell::isString() const
212{
213 return m_type == StringType;
214}
215
216inline bool JSCell::isBigInt() const
217{
218 return m_type == BigIntType;
219}
220
221inline bool JSCell::isSymbol() const
222{
223 return m_type == SymbolType;
224}
225
226inline bool JSCell::isGetterSetter() const
227{
228 return m_type == GetterSetterType;
229}
230
231inline bool JSCell::isCustomGetterSetter() const
232{
233 return m_type == CustomGetterSetterType;
234}
235
236inline bool JSCell::isProxy() const
237{
238 return m_type == ImpureProxyType || m_type == PureForwardingProxyType || m_type == ProxyObjectType;
239}
240
241ALWAYS_INLINE bool JSCell::isFunction(VM& vm)
242{
243 if (type() == JSFunctionType)
244 return true;
245 if (inlineTypeFlags() & OverridesGetCallData) {
246 CallData ignoredCallData;
247 return methodTable(vm)->getCallData(this, ignoredCallData) != CallType::None;
248 }
249 return false;
250}
251
252inline bool JSCell::isCallable(VM& vm, CallType& callType, CallData& callData)
253{
254 if (type() != JSFunctionType && !(inlineTypeFlags() & OverridesGetCallData))
255 return false;
256 callType = methodTable(vm)->getCallData(this, callData);
257 return callType != CallType::None;
258}
259
260inline bool JSCell::isConstructor(VM& vm)
261{
262 ConstructType constructType;
263 ConstructData constructData;
264 return isConstructor(vm, constructType, constructData);
265}
266
267inline bool JSCell::isConstructor(VM& vm, ConstructType& constructType, ConstructData& constructData)
268{
269 constructType = methodTable(vm)->getConstructData(this, constructData);
270 return constructType != ConstructType::None;
271}
272
273inline bool JSCell::isAPIValueWrapper() const
274{
275 return m_type == APIValueWrapperType;
276}
277
278ALWAYS_INLINE void JSCell::setStructure(VM& vm, Structure* structure)
279{
280 ASSERT(structure->classInfo() == this->structure(vm)->classInfo());
281 ASSERT(!this->structure(vm)
282 || this->structure(vm)->transitionWatchpointSetHasBeenInvalidated()
283 || Heap::heap(this)->structureIDTable().get(structure->id()) == structure);
284 m_structureID = structure->id();
285 m_flags = TypeInfo::mergeInlineTypeFlags(structure->typeInfo().inlineTypeFlags(), m_flags);
286 m_type = structure->typeInfo().type();
287 IndexingType newIndexingType = structure->indexingModeIncludingHistory();
288 if (m_indexingTypeAndMisc != newIndexingType) {
289 ASSERT(!(newIndexingType & ~AllArrayTypesAndHistory));
290 for (;;) {
291 IndexingType oldValue = m_indexingTypeAndMisc;
292 IndexingType newValue = (oldValue & ~AllArrayTypesAndHistory) | structure->indexingModeIncludingHistory();
293 if (WTF::atomicCompareExchangeWeakRelaxed(&m_indexingTypeAndMisc, oldValue, newValue))
294 break;
295 }
296 }
297 vm.heap.writeBarrier(this, structure);
298}
299
300inline const MethodTable* JSCell::methodTable(VM& vm) const
301{
302 Structure* structure = this->structure(vm);
303#if !ASSERT_DISABLED
304 if (Structure* rootStructure = structure->structure(vm))
305 ASSERT(rootStructure == rootStructure->structure(vm));
306#endif
307 return &structure->classInfo()->methodTable;
308}
309
310inline bool JSCell::inherits(VM& vm, const ClassInfo* info) const
311{
312 return classInfo(vm)->isSubClassOf(info);
313}
314
315template<typename Target>
316inline bool JSCell::inherits(VM& vm) const
317{
318 return JSCastingHelpers::inherits<Target>(vm, this);
319}
320
321ALWAYS_INLINE JSValue JSCell::fastGetOwnProperty(VM& vm, Structure& structure, PropertyName name)
322{
323 ASSERT(canUseFastGetOwnProperty(structure));
324 PropertyOffset offset = structure.get(vm, name);
325 if (offset != invalidOffset)
326 return asObject(this)->locationForOffset(offset)->get();
327 return JSValue();
328}
329
330inline bool JSCell::canUseFastGetOwnProperty(const Structure& structure)
331{
332 return !structure.hasGetterSetterProperties()
333 && !structure.hasCustomGetterSetterProperties()
334 && !structure.typeInfo().overridesGetOwnPropertySlot();
335}
336
337ALWAYS_INLINE const ClassInfo* JSCell::classInfo(VM& vm) const
338{
339 // What we really want to assert here is that we're not currently destructing this object (which makes its classInfo
340 // invalid). If mutatorState() == MutatorState::Running, then we're not currently sweeping, and therefore cannot be
341 // destructing the object. The GC thread or JIT threads, unlike the mutator thread, are able to access classInfo
342 // independent of whether the mutator thread is sweeping or not. Hence, we also check for !currentThreadIsHoldingAPILock()
343 // to allow the GC thread or JIT threads to pass this assertion.
344 ASSERT(vm.heap.mutatorState() != MutatorState::Sweeping || !vm.currentThreadIsHoldingAPILock());
345 return structure(vm)->classInfo();
346}
347
348inline bool JSCell::toBoolean(JSGlobalObject* globalObject) const
349{
350 if (isString())
351 return static_cast<const JSString*>(this)->toBoolean();
352 if (isBigInt())
353 return static_cast<const JSBigInt*>(this)->toBoolean();
354 return !structure(getVM(globalObject))->masqueradesAsUndefined(globalObject);
355}
356
357inline TriState JSCell::pureToBoolean() const
358{
359 if (isString())
360 return static_cast<const JSString*>(this)->toBoolean() ? TrueTriState : FalseTriState;
361 if (isBigInt())
362 return static_cast<const JSBigInt*>(this)->toBoolean() ? TrueTriState : FalseTriState;
363 if (isSymbol())
364 return TrueTriState;
365 return MixedTriState;
366}
367
368inline void JSCellLock::lock()
369{
370 Atomic<IndexingType>* lock = bitwise_cast<Atomic<IndexingType>*>(&m_indexingTypeAndMisc);
371 if (UNLIKELY(!IndexingTypeLockAlgorithm::lockFast(*lock)))
372 lockSlow();
373}
374
375inline bool JSCellLock::tryLock()
376{
377 Atomic<IndexingType>* lock = bitwise_cast<Atomic<IndexingType>*>(&m_indexingTypeAndMisc);
378 return IndexingTypeLockAlgorithm::tryLock(*lock);
379}
380
381inline void JSCellLock::unlock()
382{
383 Atomic<IndexingType>* lock = bitwise_cast<Atomic<IndexingType>*>(&m_indexingTypeAndMisc);
384 if (UNLIKELY(!IndexingTypeLockAlgorithm::unlockFast(*lock)))
385 unlockSlow();
386}
387
388inline bool JSCellLock::isLocked() const
389{
390 Atomic<IndexingType>* lock = bitwise_cast<Atomic<IndexingType>*>(&m_indexingTypeAndMisc);
391 return IndexingTypeLockAlgorithm::isLocked(*lock);
392}
393
394inline bool JSCell::perCellBit() const
395{
396 return TypeInfo::perCellBit(inlineTypeFlags());
397}
398
399inline void JSCell::setPerCellBit(bool value)
400{
401 if (value == perCellBit())
402 return;
403
404 if (value)
405 m_flags |= static_cast<TypeInfo::InlineTypeFlags>(TypeInfoPerCellBit);
406 else
407 m_flags &= ~static_cast<TypeInfo::InlineTypeFlags>(TypeInfoPerCellBit);
408}
409
410inline JSObject* JSCell::toObject(JSGlobalObject* globalObject) const
411{
412 if (isObject())
413 return jsCast<JSObject*>(const_cast<JSCell*>(this));
414 return toObjectSlow(globalObject);
415}
416
417ALWAYS_INLINE bool JSCell::putInline(JSGlobalObject* globalObject, PropertyName propertyName, JSValue value, PutPropertySlot& slot)
418{
419 auto putMethod = methodTable(getVM(globalObject))->put;
420 if (LIKELY(putMethod == JSObject::put))
421 return JSObject::putInlineForJSObject(asObject(this), globalObject, propertyName, value, slot);
422 return putMethod(this, globalObject, propertyName, value, slot);
423}
424
425inline bool isWebAssemblyToJSCallee(const JSCell* cell)
426{
427 return cell->type() == WebAssemblyToJSCalleeType;
428}
429
430} // namespace JSC
431