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 namespace JSC {
  37
  38 ASSERT_CLASS_FITS_IN_CELL(JSActivation);
  39
  40 const ClassInfo JSActivation::info = { "JSActivation", 0, 0, 0 };
  41
  42 JSActivation::JSActivation(CallFrame* callFrame, NonNullPassRefPtr<FunctionExecutable> functionExecutable)
  43     : Base(callFrame->globalData().activationStructure, new JSActivationData(functionExecutable, callFrame->registers()))
  44 {
  45 }
  46
  47 JSActivation::~JSActivation()
  48 {
  49     delete d();
  50 }
  51
  52 void JSActivation::markChildren(MarkStack& markStack)
  53 {
  54     Base::markChildren(markStack);
  55
  56     Register* registerArray = d()->registerArray.get();
  57     if (!registerArray)
  58         return;
  59
  60     size_t numParametersMinusThis = d()->functionExecutable->parameterCount();
  61
  62     size_t count = numParametersMinusThis;
  63     markStack.appendValues(registerArray, count);
  64
  65     size_t numVars = d()->functionExecutable->variableCount();
  66
  67     // Skip the call frame, which sits between the parameters and vars.
  68     markStack.appendValues(registerArray + count + RegisterFile::CallFrameHeaderSize, numVars, MayContainNullValues);
  69 }
  70
  71 bool JSActivation::getOwnPropertySlot(ExecState* exec, const Identifier& propertyName, PropertySlot& slot)
  72 {
  73     if (symbolTableGet(propertyName, slot))
  74         return true;
  75
  76     if (JSValue* location = getDirectLocation(propertyName)) {
  77         slot.setValueSlot(location);
  78         return true;
  79     }
  80
  81     // Only return the built-in arguments object if it wasn't overridden above.
  82     if (propertyName == exec->propertyNames().arguments) {
  83         slot.setCustom(this, getArgumentsGetter());
  84         return true;
  85     }
  86
  87     // We don't call through to JSObject because there's no way to give an
  88     // activation object getter properties or a prototype.
  89     ASSERT(!hasGetterSetterProperties());
  90     ASSERT(prototype().isNull());
  91     return false;
  92 }
  93
  94 void JSActivation::put(ExecState*, const Identifier& propertyName, JSValue value, PutPropertySlot& slot)
  95 {
  96     ASSERT(!Heap::heap(value) || Heap::heap(value) == Heap::heap(this));
  97
  98     if (symbolTablePut(propertyName, value))
  99         return;
 100
 101     // We don't call through to JSObject because __proto__ and getter/setter
 102     // properties are non-standard extensions that other implementations do not
 103     // expose in the activation object.
 104     ASSERT(!hasGetterSetterProperties());
 105     putDirect(propertyName, value, 0, true, slot);
 106 }
 107
 108 // FIXME: Make this function honor ReadOnly (const) and DontEnum
 109 void JSActivation::putWithAttributes(ExecState* exec, const Identifier& propertyName, JSValue value, unsigned attributes)
 110 {
 111     ASSERT(!Heap::heap(value) || Heap::heap(value) == Heap::heap(this));
 112
 113     if (symbolTablePutWithAttributes(propertyName, value, attributes))
 114         return;
 115
 116     // We don't call through to JSObject because __proto__ and getter/setter
 117     // properties are non-standard extensions that other implementations do not
 118     // expose in the activation object.
 119     ASSERT(!hasGetterSetterProperties());
 120     PutPropertySlot slot;
 121     JSObject::putWithAttributes(exec, propertyName, value, attributes, true, slot);
 122 }
 123
 124 bool JSActivation::deleteProperty(ExecState* exec, const Identifier& propertyName)
 125 {
 126     if (propertyName == exec->propertyNames().arguments)
 127         return false;
 128
 129     return Base::deleteProperty(exec, propertyName);
 130 }
 131
 132 JSObject* JSActivation::toThisObject(ExecState* exec) const
 133 {
 134     return exec->globalThisValue();
 135 }
 136
 137 bool JSActivation::isDynamicScope() const
 138 {
 139     return d()->functionExecutable->usesEval();
 140 }
 141
 142 JSValue JSActivation::argumentsGetter(ExecState* exec, const Identifier&, const PropertySlot& slot)
 143 {
 144     JSActivation* activation = asActivation(slot.slotBase());
 145
 146     if (activation->d()->functionExecutable->usesArguments()) {
 147         PropertySlot slot;
 148         activation->symbolTableGet(exec->propertyNames().arguments, slot);
 149         return slot.getValue(exec, exec->propertyNames().arguments);
 150     }
 151
 152     CallFrame* callFrame = CallFrame::create(activation->d()->registers);
 153     Arguments* arguments = callFrame->optionalCalleeArguments();
 154     if (!arguments) {
 155         arguments = new (callFrame) Arguments(callFrame);
 156         arguments->copyRegisters();
 157         callFrame->setCalleeArguments(arguments);
 158     }
 159     ASSERT(arguments->inherits(&Arguments::info));
 160
 161     return arguments;
 162 }
 163
 164 // These two functions serve the purpose of isolating the common case from a
 165 // PIC branch.
 166
 167 PropertySlot::GetValueFunc JSActivation::getArgumentsGetter()
 168 {
 169     return argumentsGetter;
 170 }
 171
 172 } // namespace JSC