runtime/JSActivation.h

   1 /*
   2  * Copyright (C) 2008, 2009, 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  *
   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;
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  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 JSActivation_h
  30 #define JSActivation_h
  31
  32 #include "CodeBlock.h"
  33 #include "CopiedSpaceInlines.h"
  34 #include "JSVariableObject.h"
  35 #include "Nodes.h"
  36 #include "SymbolTable.h"
  37
  38 namespace JSC {
  39
  40 class Register;
  41
  42 class JSActivation : public JSVariableObject {
  43 private:
  44     JSActivation(VM&, CallFrame*, Register*, SymbolTable*);
  45
  46 public:
  47     typedef JSVariableObject Base;
  48
  49     static JSActivation* create(VM& vm, CallFrame* callFrame, Register* registers, CodeBlock* codeBlock)
  50     {
  51         SymbolTable* symbolTable = codeBlock->symbolTable();
  52         ASSERT(codeBlock->codeType() == FunctionCode);
  53         JSActivation* activation = new (
  54             NotNull,
  55             allocateCell<JSActivation>(
  56                 vm.heap,
  57                 allocationSize(symbolTable)
  58             )
  59         ) JSActivation(vm, callFrame, registers, symbolTable);
  60         activation->finishCreation(vm);
  61         return activation;
  62     }
  63
  64     static JSActivation* create(VM& vm, CallFrame* callFrame, CodeBlock* codeBlock)
  65     {
  66         return create(vm, callFrame, callFrame->registers() + codeBlock->framePointerOffsetToGetActivationRegisters(), codeBlock);
  67     }
  68
  69     static void visitChildren(JSCell*, SlotVisitor&);
  70
  71     static bool getOwnPropertySlot(JSObject*, ExecState*, PropertyName, PropertySlot&);
  72     static void getOwnNonIndexPropertyNames(JSObject*, ExecState*, PropertyNameArray&, EnumerationMode);
  73
  74     static void put(JSCell*, ExecState*, PropertyName, JSValue, PutPropertySlot&);
  75
  76     static bool deleteProperty(JSCell*, ExecState*, PropertyName);
  77
  78     static JSValue toThis(JSCell*, ExecState*, ECMAMode);
  79
  80     void tearOff(VM&);
  81
  82     DECLARE_INFO;
  83
  84     static Structure* createStructure(VM& vm, JSGlobalObject* globalObject, JSValue proto) { return Structure::create(vm, globalObject, proto, TypeInfo(ActivationObjectType, StructureFlags), info()); }
  85
  86     WriteBarrierBase<Unknown>& registerAt(int) const;
  87     bool isValidIndex(int) const;
  88     bool isValid(const SymbolTableEntry&) const;
  89     bool isTornOff();
  90     int registersOffset();
  91     static int registersOffset(SymbolTable*);
  92
  93 protected:
  94     static const unsigned StructureFlags = OverridesGetOwnPropertySlot | OverridesVisitChildren | OverridesGetPropertyNames | Base::StructureFlags;
  95
  96 private:
  97     bool symbolTableGet(PropertyName, PropertySlot&);
  98     bool symbolTableGet(PropertyName, PropertyDescriptor&);
  99     bool symbolTableGet(PropertyName, PropertySlot&, bool& slotIsWriteable);
 100     bool symbolTablePut(ExecState*, PropertyName, JSValue, bool shouldThrow);
 101     bool symbolTablePutWithAttributes(VM&, PropertyName, JSValue, unsigned attributes);
 102
 103     static EncodedJSValue argumentsGetter(ExecState*, JSObject*, EncodedJSValue, PropertyName);
 104
 105     static size_t allocationSize(SymbolTable*);
 106     static size_t storageOffset();
 107
 108     WriteBarrier<Unknown>* storage(); // captureCount() number of registers.
 109 };
 110
 111 extern int activationCount;
 112 extern int allTheThingsCount;
 113
 114 inline JSActivation::JSActivation(VM& vm, CallFrame* callFrame, Register* registers, SymbolTable* symbolTable)
 115     : Base(
 116         vm,
 117         callFrame->lexicalGlobalObject()->activationStructure(),
 118         registers,
 119         callFrame->scope(),
 120         symbolTable)
 121 {
 122     WriteBarrier<Unknown>* storage = this->storage();
 123     size_t captureCount = symbolTable->captureCount();
 124     for (size_t i = 0; i < captureCount; ++i)
 125         new (NotNull, &storage[i]) WriteBarrier<Unknown>;
 126 }
 127
 128 JSActivation* asActivation(JSValue);
 129
 130 inline JSActivation* asActivation(JSValue value)
 131 {
 132     ASSERT(asObject(value)->inherits(JSActivation::info()));
 133     return jsCast<JSActivation*>(asObject(value));
 134 }
 135
 136 ALWAYS_INLINE JSActivation* Register::activation() const
 137 {
 138     return asActivation(jsValue());
 139 }
 140
 141 inline int JSActivation::registersOffset(SymbolTable* symbolTable)
 142 {
 143     return storageOffset() + ((symbolTable->captureCount() - symbolTable->captureStart()  - 1) * sizeof(WriteBarrier<Unknown>));
 144 }
 145
 146 inline void JSActivation::tearOff(VM& vm)
 147 {
 148     ASSERT(!isTornOff());
 149
 150     WriteBarrierBase<Unknown>* dst = reinterpret_cast_ptr<WriteBarrierBase<Unknown>*>(
 151         reinterpret_cast<char*>(this) + registersOffset(symbolTable()));
 152     WriteBarrierBase<Unknown>* src = m_registers;
 153
 154     int captureEnd = symbolTable()->captureEnd();
 155     for (int i = symbolTable()->captureStart(); i > captureEnd; --i)
 156         dst[i].set(vm, this, src[i].get());
 157
 158     m_registers = dst;
 159     ASSERT(isTornOff());
 160 }
 161
 162 inline bool JSActivation::isTornOff()
 163 {
 164     return m_registers == reinterpret_cast_ptr<WriteBarrierBase<Unknown>*>(
 165         reinterpret_cast<char*>(this) + registersOffset(symbolTable()));
 166 }
 167
 168 inline size_t JSActivation::storageOffset()
 169 {
 170     return WTF::roundUpToMultipleOf<sizeof(WriteBarrier<Unknown>)>(sizeof(JSActivation));
 171 }
 172
 173 inline WriteBarrier<Unknown>* JSActivation::storage()
 174 {
 175     return reinterpret_cast_ptr<WriteBarrier<Unknown>*>(
 176         reinterpret_cast<char*>(this) + storageOffset());
 177 }
 178
 179 inline size_t JSActivation::allocationSize(SymbolTable* symbolTable)
 180 {
 181     size_t objectSizeInBytes = WTF::roundUpToMultipleOf<sizeof(WriteBarrier<Unknown>)>(sizeof(JSActivation));
 182     size_t storageSizeInBytes = symbolTable->captureCount() * sizeof(WriteBarrier<Unknown>);
 183     return objectSizeInBytes + storageSizeInBytes;
 184 }
 185
 186 inline bool JSActivation::isValidIndex(int index) const
 187 {
 188     if (index > symbolTable()->captureStart())
 189         return false;
 190     if (index <= symbolTable()->captureEnd())
 191         return false;
 192     return true;
 193 }
 194
 195 inline bool JSActivation::isValid(const SymbolTableEntry& entry) const
 196 {
 197     return isValidIndex(entry.getIndex());
 198 }
 199
 200 inline WriteBarrierBase<Unknown>& JSActivation::registerAt(int index) const
 201 {
 202     ASSERT(isValidIndex(index));
 203     return Base::registerAt(index);
 204 }
 205
 206 } // namespace JSC
 207
 208 #endif // JSActivation_h