runtime/JSCellInlines.h

   1 /*
   2  * Copyright (C) 2012, 2013 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 #ifndef JSCellInlines_h
  27 #define JSCellInlines_h
  28
  29 #include "CallFrame.h"
  30 #include "DeferGC.h"
  31 #include "Handle.h"
  32 #include "JSCell.h"
  33 #include "JSDestructibleObject.h"
  34 #include "JSObject.h"
  35 #include "JSString.h"
  36 #include "MarkedBlock.h"
  37 #include "Structure.h"
  38 #include "Symbol.h"
  39 #include <wtf/CompilationThread.h>
  40
  41 namespace JSC {
  42
  43 inline JSCell::JSCell(CreatingEarlyCellTag)
  44     : m_gcData(NotMarked)
  45 {
  46     ASSERT(!isCompilationThread());
  47 }
  48
  49 inline JSCell::JSCell(VM&, Structure* structure)
  50     : m_structureID(structure->id())
  51     , m_indexingType(structure->indexingType())
  52     , m_type(structure->typeInfo().type())
  53     , m_flags(structure->typeInfo().inlineTypeFlags())
  54     , m_gcData(NotMarked)
  55 {
  56     ASSERT(!isCompilationThread());
  57 }
  58
  59 inline void JSCell::finishCreation(VM& vm)
  60 {
  61 #if ENABLE(GC_VALIDATION)
  62     ASSERT(vm.isInitializingObject());
  63     vm.setInitializingObjectClass(0);
  64 #else
  65     UNUSED_PARAM(vm);
  66 #endif
  67     ASSERT(m_structureID);
  68 }
  69
  70 inline void JSCell::finishCreation(VM& vm, Structure* structure, CreatingEarlyCellTag)
  71 {
  72 #if ENABLE(GC_VALIDATION)
  73     ASSERT(vm.isInitializingObject());
  74     vm.setInitializingObjectClass(0);
  75     if (structure) {
  76 #endif
  77         m_structureID = structure->id();
  78         m_indexingType = structure->indexingType();
  79         m_type = structure->typeInfo().type();
  80         m_flags = structure->typeInfo().inlineTypeFlags();
  81 #if ENABLE(GC_VALIDATION)
  82     }
  83 #else
  84     UNUSED_PARAM(vm);
  85 #endif
  86     // Very first set of allocations won't have a real structure.
  87     ASSERT(m_structureID || !vm.structureStructure);
  88 }
  89
  90 inline JSType JSCell::type() const
  91 {
  92     return m_type;
  93 }
  94
  95 inline IndexingType JSCell::indexingType() const
  96 {
  97     return m_indexingType;
  98 }
  99
 100 inline Structure* JSCell::structure() const
 101 {
 102     return Heap::heap(this)->structureIDTable().get(m_structureID);
 103 }
 104
 105 inline Structure* JSCell::structure(VM& vm) const
 106 {
 107     return vm.heap.structureIDTable().get(m_structureID);
 108 }
 109
 110 inline void JSCell::visitChildren(JSCell* cell, SlotVisitor& visitor)
 111 {
 112     Structure* structure = cell->structure(visitor.vm());
 113     visitor.appendUnbarrieredPointer(&structure);
 114 }
 115
 116 inline VM* JSCell::vm() const
 117 {
 118     return MarkedBlock::blockFor(this)->vm();
 119 }
 120
 121 inline VM& ExecState::vm() const
 122 {
 123     ASSERT(callee());
 124     ASSERT(callee()->vm());
 125     return *calleeAsValue().asCell()->vm();
 126 }
 127
 128 template<typename T>
 129 void* allocateCell(Heap& heap, size_t size)
 130 {
 131     ASSERT(!DisallowGC::isGCDisallowedOnCurrentThread());
 132     ASSERT(size >= sizeof(T));
 133     JSCell* result = static_cast<JSCell*>(heap.allocateObjectOfType<T>(size));
 134 #if ENABLE(GC_VALIDATION)
 135     ASSERT(!heap.vm()->isInitializingObject());
 136     heap.vm()->setInitializingObjectClass(T::info());
 137 #endif
 138     result->clearStructure();
 139     return result;
 140 }
 141
 142 template<typename T>
 143 void* allocateCell(Heap& heap)
 144 {
 145     return allocateCell<T>(heap, sizeof(T));
 146 }
 147
 148 inline bool isZapped(const JSCell* cell)
 149 {
 150     return cell->isZapped();
 151 }
 152
 153 inline bool JSCell::isObject() const
 154 {
 155     return TypeInfo::isObject(m_type);
 156 }
 157
 158 inline bool JSCell::isString() const
 159 {
 160     return m_type == StringType;
 161 }
 162
 163 inline bool JSCell::isSymbol() const
 164 {
 165     return m_type == SymbolType;
 166 }
 167
 168 inline bool JSCell::isGetterSetter() const
 169 {
 170     return m_type == GetterSetterType;
 171 }
 172
 173 inline bool JSCell::isCustomGetterSetter() const
 174 {
 175     return m_type == CustomGetterSetterType;
 176 }
 177
 178 inline bool JSCell::isProxy() const
 179 {
 180     return m_type == ImpureProxyType || m_type == PureForwardingProxyType;
 181 }
 182
 183 inline bool JSCell::isAPIValueWrapper() const
 184 {
 185     return m_type == APIValueWrapperType;
 186 }
 187
 188 inline void JSCell::setStructure(VM& vm, Structure* structure)
 189 {
 190     ASSERT(structure->classInfo() == this->structure()->classInfo());
 191     ASSERT(!this->structure()
 192         || this->structure()->transitionWatchpointSetHasBeenInvalidated()
 193         || Heap::heap(this)->structureIDTable().get(structure->id()) == structure);
 194     vm.heap.writeBarrier(this, structure);
 195     m_structureID = structure->id();
 196     m_flags = structure->typeInfo().inlineTypeFlags();
 197     m_type = structure->typeInfo().type();
 198     m_indexingType = structure->indexingType();
 199 }
 200
 201 inline const MethodTable* JSCell::methodTable() const
 202 {
 203     VM& vm = *Heap::heap(this)->vm();
 204     Structure* structure = this->structure(vm);
 205     if (Structure* rootStructure = structure->structure(vm))
 206         RELEASE_ASSERT(rootStructure == rootStructure->structure(vm));
 207
 208     return &structure->classInfo()->methodTable;
 209 }
 210
 211 inline const MethodTable* JSCell::methodTable(VM& vm) const
 212 {
 213     Structure* structure = this->structure(vm);
 214     if (Structure* rootStructure = structure->structure(vm))
 215         RELEASE_ASSERT(rootStructure == rootStructure->structure(vm));
 216
 217     return &structure->classInfo()->methodTable;
 218 }
 219
 220 inline bool JSCell::inherits(const ClassInfo* info) const
 221 {
 222     return classInfo()->isSubClassOf(info);
 223 }
 224
 225 ALWAYS_INLINE JSValue JSCell::fastGetOwnProperty(VM& vm, Structure& structure, PropertyName name)
 226 {
 227     ASSERT(canUseFastGetOwnProperty(structure));
 228     PropertyOffset offset = structure.get(vm, name);
 229     if (offset != invalidOffset)
 230         return asObject(this)->locationForOffset(offset)->get();
 231     return JSValue();
 232 }
 233
 234 inline bool JSCell::canUseFastGetOwnProperty(const Structure& structure)
 235 {
 236     return !structure.hasGetterSetterProperties()
 237         && !structure.hasCustomGetterSetterProperties()
 238         && !structure.typeInfo().overridesGetOwnPropertySlot();
 239 }
 240
 241 inline const ClassInfo* JSCell::classInfo() const
 242 {
 243     MarkedBlock* block = MarkedBlock::blockFor(this);
 244     if (block->needsDestruction() && !(inlineTypeFlags() & StructureIsImmortal))
 245         return static_cast<const JSDestructibleObject*>(this)->classInfo();
 246     return structure(*block->vm())->classInfo();
 247 }
 248
 249 inline bool JSCell::toBoolean(ExecState* exec) const
 250 {
 251     if (isString())
 252         return static_cast<const JSString*>(this)->toBoolean();
 253     return !structure()->masqueradesAsUndefined(exec->lexicalGlobalObject());
 254 }
 255
 256 inline TriState JSCell::pureToBoolean() const
 257 {
 258     if (isString())
 259         return static_cast<const JSString*>(this)->toBoolean() ? TrueTriState : FalseTriState;
 260     if (isSymbol())
 261         return TrueTriState;
 262     return MixedTriState;
 263 }
 264
 265 } // namespace JSC
 266
 267 #endif // JSCellInlines_h