runtime/JSActivation.cpp

   1 /*
   2  * Copyright (C) 2008 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, PassRefPtr<FunctionBodyNode> functionBody)
  43     : Base(callFrame->globalData().activationStructure, new JSActivationData(functionBody, callFrame))
  44 {
  45 }
  46
  47 JSActivation::~JSActivation()
  48 {
  49     delete d();
  50 }
  51
  52 void JSActivation::mark()
  53 {
  54     Base::mark();
  55
  56     Register* registerArray = d()->registerArray.get();
  57     if (!registerArray)
  58         return;
  59
  60     size_t numParametersMinusThis = d()->functionBody->generatedBytecode().m_numParameters - 1;
  61
  62     size_t i = 0;
  63     size_t count = numParametersMinusThis;
  64     for ( ; i < count; ++i) {
  65         Register& r = registerArray[i];
  66         if (!r.marked())
  67             r.mark();
  68     }
  69
  70     size_t numVars = d()->functionBody->generatedBytecode().m_numVars;
  71
  72     // Skip the call frame, which sits between the parameters and vars.
  73     i += RegisterFile::CallFrameHeaderSize;
  74     count += RegisterFile::CallFrameHeaderSize + numVars;
  75
  76     for ( ; i < count; ++i) {
  77         Register& r = registerArray[i];
  78         if (!r.marked())
  79             r.mark();
  80     }
  81 }
  82
  83 bool JSActivation::getOwnPropertySlot(ExecState* exec, const Identifier& propertyName, PropertySlot& slot)
  84 {
  85     if (symbolTableGet(propertyName, slot))
  86         return true;
  87
  88     if (JSValuePtr* location = getDirectLocation(propertyName)) {
  89         slot.setValueSlot(location);
  90         return true;
  91     }
  92
  93     // Only return the built-in arguments object if it wasn't overridden above.
  94     if (propertyName == exec->propertyNames().arguments) {
  95         slot.setCustom(this, getArgumentsGetter());
  96         return true;
  97     }
  98
  99     // We don't call through to JSObject because there's no way to give an
 100     // activation object getter properties or a prototype.
 101     ASSERT(!hasGetterSetterProperties());
 102     ASSERT(prototype().isNull());
 103     return false;
 104 }
 105
 106 void JSActivation::put(ExecState*, const Identifier& propertyName, JSValuePtr value, PutPropertySlot& slot)
 107 {
 108     ASSERT(!Heap::heap(value) || Heap::heap(value) == Heap::heap(this));
 109
 110     if (symbolTablePut(propertyName, value))
 111         return;
 112
 113     // We don't call through to JSObject because __proto__ and getter/setter
 114     // properties are non-standard extensions that other implementations do not
 115     // expose in the activation object.
 116     ASSERT(!hasGetterSetterProperties());
 117     putDirect(propertyName, value, 0, true, slot);
 118 }
 119
 120 // FIXME: Make this function honor ReadOnly (const) and DontEnum
 121 void JSActivation::putWithAttributes(ExecState*, const Identifier& propertyName, JSValuePtr value, unsigned attributes)
 122 {
 123     ASSERT(!Heap::heap(value) || Heap::heap(value) == Heap::heap(this));
 124
 125     if (symbolTablePutWithAttributes(propertyName, value, attributes))
 126         return;
 127
 128     // We don't call through to JSObject because __proto__ and getter/setter
 129     // properties are non-standard extensions that other implementations do not
 130     // expose in the activation object.
 131     ASSERT(!hasGetterSetterProperties());
 132     PutPropertySlot slot;
 133     putDirect(propertyName, value, attributes, true, slot);
 134 }
 135
 136 bool JSActivation::deleteProperty(ExecState* exec, const Identifier& propertyName)
 137 {
 138     if (propertyName == exec->propertyNames().arguments)
 139         return false;
 140
 141     return Base::deleteProperty(exec, propertyName);
 142 }
 143
 144 JSObject* JSActivation::toThisObject(ExecState* exec) const
 145 {
 146     return exec->globalThisValue();
 147 }
 148
 149 bool JSActivation::isDynamicScope() const
 150 {
 151     return d()->functionBody->usesEval();
 152 }
 153
 154 JSValuePtr JSActivation::argumentsGetter(ExecState* exec, const Identifier&, const PropertySlot& slot)
 155 {
 156     JSActivation* activation = asActivation(slot.slotBase());
 157
 158     if (activation->d()->functionBody->usesArguments()) {
 159         PropertySlot slot;
 160         activation->symbolTableGet(exec->propertyNames().arguments, slot);
 161         return slot.getValue(exec, exec->propertyNames().arguments);
 162     }
 163
 164     CallFrame* callFrame = CallFrame::create(activation->d()->registers);
 165     Arguments* arguments = callFrame->optionalCalleeArguments();
 166     if (!arguments) {
 167         arguments = new (callFrame) Arguments(callFrame);
 168         arguments->copyRegisters();
 169         callFrame->setCalleeArguments(arguments);
 170     }
 171     ASSERT(arguments->isObject(&Arguments::info));
 172
 173     return arguments;
 174 }
 175
 176 // These two functions serve the purpose of isolating the common case from a
 177 // PIC branch.
 178
 179 PropertySlot::GetValueFunc JSActivation::getArgumentsGetter()
 180 {
 181     return argumentsGetter;
 182 }
 183
 184 } // namespace JSC