runtime/JSActivation.cpp

   1 /*
   2  * Copyright (C) 2008, 2009 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 Computer, 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 #include "config.h"
  30 #include "JSActivation.h"
  31
  32 #include "Arguments.h"
  33 #include "Interpreter.h"
  34 #include "JSFunction.h"
  35
  36 using namespace std;
  37
  38 namespace JSC {
  39
  40 ASSERT_CLASS_FITS_IN_CELL(JSActivation);
  41
  42 const ClassInfo JSActivation::s_info = { "JSActivation", &Base::s_info, 0, 0, CREATE_METHOD_TABLE(JSActivation) };
  43
  44 JSActivation::JSActivation(CallFrame* callFrame, FunctionExecutable* functionExecutable)
  45     : Base(callFrame->globalData(), callFrame->globalData().activationStructure.get(), functionExecutable->symbolTable(), callFrame->registers())
  46     , m_numCapturedArgs(max(callFrame->argumentCount(), functionExecutable->parameterCount()))
  47     , m_numCapturedVars(functionExecutable->capturedVariableCount())
  48     , m_isTornOff(false)
  49     , m_requiresDynamicChecks(functionExecutable->usesEval() && !functionExecutable->isStrictMode())
  50     , m_argumentsRegister(functionExecutable->generatedBytecode().argumentsRegister())
  51 {
  52 }
  53
  54 void JSActivation::finishCreation(CallFrame* callFrame)
  55 {
  56     Base::finishCreation(callFrame->globalData());
  57     ASSERT(inherits(&s_info));
  58
  59     // We have to manually ref and deref the symbol table as JSVariableObject
  60     // doesn't know about SharedSymbolTable
  61     static_cast<SharedSymbolTable*>(m_symbolTable)->ref();
  62     callFrame->globalData().heap.addFinalizer(this, &finalize);
  63 }
  64
  65 void JSActivation::finalize(JSCell* cell)
  66 {
  67     static_cast<SharedSymbolTable*>(jsCast<JSActivation*>(cell)->m_symbolTable)->deref();
  68 }
  69
  70 void JSActivation::visitChildren(JSCell* cell, SlotVisitor& visitor)
  71 {
  72     JSActivation* thisObject = jsCast<JSActivation*>(cell);
  73     ASSERT_GC_OBJECT_INHERITS(thisObject, &s_info);
  74     COMPILE_ASSERT(StructureFlags & OverridesVisitChildren, OverridesVisitChildrenWithoutSettingFlag);
  75     ASSERT(thisObject->structure()->typeInfo().overridesVisitChildren());
  76     Base::visitChildren(thisObject, visitor);
  77
  78     // No need to mark our registers if they're still in the RegisterFile.
  79     WriteBarrier<Unknown>* registerArray = thisObject->m_registerArray.get();
  80     if (!registerArray)
  81         return;
  82
  83     visitor.appendValues(registerArray, thisObject->m_numCapturedArgs);
  84
  85     // Skip 'this' and call frame, except for callee and scope chain.
  86     int offset = CallFrame::offsetFor(thisObject->m_numCapturedArgs + 1);
  87     visitor.append(registerArray + offset + RegisterFile::ScopeChain);
  88     visitor.append(registerArray + offset + RegisterFile::Callee);
  89
  90     visitor.appendValues(registerArray + offset, thisObject->m_numCapturedVars);
  91 }
  92
  93 inline bool JSActivation::symbolTableGet(const Identifier& propertyName, PropertySlot& slot)
  94 {
  95     SymbolTableEntry entry = symbolTable().inlineGet(propertyName.impl());
  96     if (entry.isNull())
  97         return false;
  98     if (m_isTornOff && entry.getIndex() >= m_numCapturedVars)
  99         return false;
 100
 101     slot.setValue(registerAt(entry.getIndex()).get());
 102     return true;
 103 }
 104
 105 inline bool JSActivation::symbolTablePut(ExecState* exec, const Identifier& propertyName, JSValue value, bool shouldThrow)
 106 {
 107     JSGlobalData& globalData = exec->globalData();
 108     ASSERT(!Heap::heap(value) || Heap::heap(value) == Heap::heap(this));
 109
 110     SymbolTableEntry entry = symbolTable().inlineGet(propertyName.impl());
 111     if (entry.isNull())
 112         return false;
 113     if (entry.isReadOnly()) {
 114         if (shouldThrow)
 115             throwTypeError(exec, StrictModeReadonlyPropertyWriteError);
 116         return true;
 117     }
 118     if (m_isTornOff && entry.getIndex() >= m_numCapturedVars)
 119         return false;
 120
 121     registerAt(entry.getIndex()).set(globalData, this, value);
 122     return true;
 123 }
 124
 125 void JSActivation::getOwnPropertyNames(JSObject* object, ExecState* exec, PropertyNameArray& propertyNames, EnumerationMode mode)
 126 {
 127     JSActivation* thisObject = jsCast<JSActivation*>(object);
 128     SymbolTable::const_iterator end = thisObject->symbolTable().end();
 129     for (SymbolTable::const_iterator it = thisObject->symbolTable().begin(); it != end; ++it) {
 130         if (it->second.getAttributes() & DontEnum && mode != IncludeDontEnumProperties)
 131             continue;
 132         if (it->second.getIndex() >= thisObject->m_numCapturedVars)
 133             continue;
 134         propertyNames.add(Identifier(exec, it->first.get()));
 135     }
 136     // Skip the JSVariableObject implementation of getOwnPropertyNames
 137     JSObject::getOwnPropertyNames(thisObject, exec, propertyNames, mode);
 138 }
 139
 140 inline bool JSActivation::symbolTablePutWithAttributes(JSGlobalData& globalData, const Identifier& propertyName, JSValue value, unsigned attributes)
 141 {
 142     ASSERT(!Heap::heap(value) || Heap::heap(value) == Heap::heap(this));
 143
 144     SymbolTable::iterator iter = symbolTable().find(propertyName.impl());
 145     if (iter == symbolTable().end())
 146         return false;
 147     SymbolTableEntry& entry = iter->second;
 148     ASSERT(!entry.isNull());
 149     if (entry.getIndex() >= m_numCapturedVars)
 150         return false;
 151
 152     entry.setAttributes(attributes);
 153     registerAt(entry.getIndex()).set(globalData, this, value);
 154     return true;
 155 }
 156
 157 bool JSActivation::getOwnPropertySlot(JSCell* cell, ExecState* exec, const Identifier& propertyName, PropertySlot& slot)
 158 {
 159     JSActivation* thisObject = jsCast<JSActivation*>(cell);
 160     if (propertyName == exec->propertyNames().arguments) {
 161         slot.setCustom(thisObject, thisObject->getArgumentsGetter());
 162         return true;
 163     }
 164
 165     if (thisObject->symbolTableGet(propertyName, slot))
 166         return true;
 167
 168     if (WriteBarrierBase<Unknown>* location = thisObject->getDirectLocation(exec->globalData(), propertyName)) {
 169         slot.setValue(location->get());
 170         return true;
 171     }
 172
 173     // We don't call through to JSObject because there's no way to give an
 174     // activation object getter properties or a prototype.
 175     ASSERT(!thisObject->hasGetterSetterProperties());
 176     ASSERT(thisObject->prototype().isNull());
 177     return false;
 178 }
 179
 180 void JSActivation::put(JSCell* cell, ExecState* exec, const Identifier& propertyName, JSValue value, PutPropertySlot& slot)
 181 {
 182     JSActivation* thisObject = jsCast<JSActivation*>(cell);
 183     ASSERT(!Heap::heap(value) || Heap::heap(value) == Heap::heap(thisObject));
 184
 185     if (thisObject->symbolTablePut(exec, propertyName, value, slot.isStrictMode()))
 186         return;
 187
 188     // We don't call through to JSObject because __proto__ and getter/setter
 189     // properties are non-standard extensions that other implementations do not
 190     // expose in the activation object.
 191     ASSERT(!thisObject->hasGetterSetterProperties());
 192     thisObject->putOwnDataProperty(exec->globalData(), propertyName, value, slot);
 193 }
 194
 195 // FIXME: Make this function honor ReadOnly (const) and DontEnum
 196 void JSActivation::putDirectVirtual(JSObject* object, ExecState* exec, const Identifier& propertyName, JSValue value, unsigned attributes)
 197 {
 198     JSActivation* thisObject = jsCast<JSActivation*>(object);
 199     ASSERT(!Heap::heap(value) || Heap::heap(value) == Heap::heap(thisObject));
 200
 201     if (thisObject->symbolTablePutWithAttributes(exec->globalData(), propertyName, value, attributes))
 202         return;
 203
 204     // We don't call through to JSObject because __proto__ and getter/setter
 205     // properties are non-standard extensions that other implementations do not
 206     // expose in the activation object.
 207     ASSERT(!thisObject->hasGetterSetterProperties());
 208     JSObject::putDirectVirtual(thisObject, exec, propertyName, value, attributes);
 209 }
 210
 211 bool JSActivation::deleteProperty(JSCell* cell, ExecState* exec, const Identifier& propertyName)
 212 {
 213     if (propertyName == exec->propertyNames().arguments)
 214         return false;
 215
 216     return Base::deleteProperty(cell, exec, propertyName);
 217 }
 218
 219 JSObject* JSActivation::toThisObject(JSCell*, ExecState* exec)
 220 {
 221     return exec->globalThisValue();
 222 }
 223
 224 JSValue JSActivation::argumentsGetter(ExecState*, JSValue slotBase, const Identifier&)
 225 {
 226     JSActivation* activation = asActivation(slotBase);
 227     CallFrame* callFrame = CallFrame::create(reinterpret_cast<Register*>(activation->m_registers));
 228     int argumentsRegister = activation->m_argumentsRegister;
 229     if (JSValue arguments = callFrame->uncheckedR(argumentsRegister).jsValue())
 230         return arguments;
 231     int realArgumentsRegister = unmodifiedArgumentsRegister(argumentsRegister);
 232
 233     JSValue arguments = JSValue(Arguments::create(callFrame->globalData(), callFrame));
 234     callFrame->uncheckedR(argumentsRegister) = arguments;
 235     callFrame->uncheckedR(realArgumentsRegister) = arguments;
 236
 237     ASSERT(callFrame->uncheckedR(realArgumentsRegister).jsValue().inherits(&Arguments::s_info));
 238     return callFrame->uncheckedR(realArgumentsRegister).jsValue();
 239 }
 240
 241 // These two functions serve the purpose of isolating the common case from a
 242 // PIC branch.
 243
 244 PropertySlot::GetValueFunc JSActivation::getArgumentsGetter()
 245 {
 246     return argumentsGetter;
 247 }
 248
 249 } // namespace JSC