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 #include "Operations.h"
  36
  37 using namespace std;
  38
  39 namespace JSC {
  40
  41 const ClassInfo JSActivation::s_info = { "JSActivation", &Base::s_info, 0, 0, CREATE_METHOD_TABLE(JSActivation) };
  42
  43 void JSActivation::visitChildren(JSCell* cell, SlotVisitor& visitor)
  44 {
  45     JSActivation* thisObject = jsCast<JSActivation*>(cell);
  46     ASSERT_GC_OBJECT_INHERITS(thisObject, &s_info);
  47     COMPILE_ASSERT(StructureFlags & OverridesVisitChildren, OverridesVisitChildrenWithoutSettingFlag);
  48     ASSERT(thisObject->structure()->typeInfo().overridesVisitChildren());
  49     Base::visitChildren(thisObject, visitor);
  50
  51     // No need to mark our registers if they're still in the JSStack.
  52     if (!thisObject->isTornOff())
  53         return;
  54
  55     for (int i = 0; i < thisObject->symbolTable()->captureCount(); ++i)
  56         visitor.append(&thisObject->storage()[i]);
  57 }
  58
  59 inline bool JSActivation::symbolTableGet(PropertyName propertyName, PropertySlot& slot)
  60 {
  61     SymbolTableEntry entry = symbolTable()->inlineGet(propertyName.publicName());
  62     if (entry.isNull())
  63         return false;
  64
  65     // Defend against the inspector asking for a var after it has been optimized out.
  66     if (isTornOff() && !isValid(entry))
  67         return false;
  68
  69     slot.setValue(registerAt(entry.getIndex()).get());
  70     return true;
  71 }
  72
  73 inline bool JSActivation::symbolTableGet(PropertyName propertyName, PropertyDescriptor& descriptor)
  74 {
  75     SymbolTableEntry entry = symbolTable()->inlineGet(propertyName.publicName());
  76     if (entry.isNull())
  77         return false;
  78
  79     // Defend against the inspector asking for a var after it has been optimized out.
  80     if (isTornOff() && !isValid(entry))
  81         return false;
  82
  83     descriptor.setDescriptor(registerAt(entry.getIndex()).get(), entry.getAttributes());
  84     return true;
  85 }
  86
  87 inline bool JSActivation::symbolTablePut(ExecState* exec, PropertyName propertyName, JSValue value, bool shouldThrow)
  88 {
  89     VM& vm = exec->vm();
  90     ASSERT(!Heap::heap(value) || Heap::heap(value) == Heap::heap(this));
  91
  92     SymbolTableEntry entry = symbolTable()->inlineGet(propertyName.publicName());
  93     if (entry.isNull())
  94         return false;
  95     if (entry.isReadOnly()) {
  96         if (shouldThrow)
  97             throwTypeError(exec, StrictModeReadonlyPropertyWriteError);
  98         return true;
  99     }
 100
 101     // Defend against the inspector asking for a var after it has been optimized out.
 102     if (isTornOff() && !isValid(entry))
 103         return false;
 104
 105     registerAt(entry.getIndex()).set(vm, this, value);
 106     return true;
 107 }
 108
 109 void JSActivation::getOwnNonIndexPropertyNames(JSObject* object, ExecState* exec, PropertyNameArray& propertyNames, EnumerationMode mode)
 110 {
 111     JSActivation* thisObject = jsCast<JSActivation*>(object);
 112
 113     if (mode == IncludeDontEnumProperties && !thisObject->isTornOff())
 114         propertyNames.add(exec->propertyNames().arguments);
 115
 116     SymbolTable::const_iterator end = thisObject->symbolTable()->end();
 117     for (SymbolTable::const_iterator it = thisObject->symbolTable()->begin(); it != end; ++it) {
 118         if (it->value.getAttributes() & DontEnum && mode != IncludeDontEnumProperties)
 119             continue;
 120         if (!thisObject->isValid(it->value))
 121             continue;
 122         propertyNames.add(Identifier(exec, it->key.get()));
 123     }
 124     // Skip the JSVariableObject implementation of getOwnNonIndexPropertyNames
 125     JSObject::getOwnNonIndexPropertyNames(thisObject, exec, propertyNames, mode);
 126 }
 127
 128 inline bool JSActivation::symbolTablePutWithAttributes(VM& vm, PropertyName propertyName, JSValue value, unsigned attributes)
 129 {
 130     ASSERT(!Heap::heap(value) || Heap::heap(value) == Heap::heap(this));
 131
 132     SymbolTable::iterator iter = symbolTable()->find(propertyName.publicName());
 133     if (iter == symbolTable()->end())
 134         return false;
 135     SymbolTableEntry& entry = iter->value;
 136     ASSERT(!entry.isNull());
 137     if (!isValid(entry))
 138         return false;
 139
 140     entry.setAttributes(attributes);
 141     registerAt(entry.getIndex()).set(vm, this, value);
 142     return true;
 143 }
 144
 145 bool JSActivation::getOwnPropertySlot(JSCell* cell, ExecState* exec, PropertyName propertyName, PropertySlot& slot)
 146 {
 147     JSActivation* thisObject = jsCast<JSActivation*>(cell);
 148
 149     if (propertyName == exec->propertyNames().arguments) {
 150         // Defend against the inspector asking for the arguments object after it has been optimized out.
 151         if (!thisObject->isTornOff()) {
 152             slot.setCustom(thisObject, thisObject->getArgumentsGetter());
 153             return true;
 154         }
 155     }
 156
 157     if (thisObject->symbolTableGet(propertyName, slot))
 158         return true;
 159
 160     if (JSValue value = thisObject->getDirect(exec->vm(), propertyName)) {
 161         slot.setValue(value);
 162         return true;
 163     }
 164
 165     // We don't call through to JSObject because there's no way to give an
 166     // activation object getter properties or a prototype.
 167     ASSERT(!thisObject->hasGetterSetterProperties());
 168     ASSERT(thisObject->prototype().isNull());
 169     return false;
 170 }
 171
 172 bool JSActivation::getOwnPropertyDescriptor(JSObject* object, ExecState* exec, PropertyName propertyName, PropertyDescriptor& descriptor)
 173 {
 174     JSActivation* thisObject = jsCast<JSActivation*>(object);
 175
 176     if (propertyName == exec->propertyNames().arguments) {
 177         // Defend against the inspector asking for the arguments object after it has been optimized out.
 178         if (!thisObject->isTornOff()) {
 179             PropertySlot slot;
 180             JSActivation::getOwnPropertySlot(thisObject, exec, propertyName, slot);
 181             descriptor.setDescriptor(slot.getValue(exec, propertyName), DontEnum);
 182             return true;
 183         }
 184     }
 185
 186     if (thisObject->symbolTableGet(propertyName, descriptor))
 187         return true;
 188
 189     return Base::getOwnPropertyDescriptor(object, exec, propertyName, descriptor);
 190 }
 191
 192 void JSActivation::put(JSCell* cell, ExecState* exec, PropertyName propertyName, JSValue value, PutPropertySlot& slot)
 193 {
 194     JSActivation* thisObject = jsCast<JSActivation*>(cell);
 195     ASSERT(!Heap::heap(value) || Heap::heap(value) == Heap::heap(thisObject));
 196
 197     if (thisObject->symbolTablePut(exec, propertyName, value, slot.isStrictMode()))
 198         return;
 199
 200     // We don't call through to JSObject because __proto__ and getter/setter
 201     // properties are non-standard extensions that other implementations do not
 202     // expose in the activation object.
 203     ASSERT(!thisObject->hasGetterSetterProperties());
 204     thisObject->putOwnDataProperty(exec->vm(), propertyName, value, slot);
 205 }
 206
 207 // FIXME: Make this function honor ReadOnly (const) and DontEnum
 208 void JSActivation::putDirectVirtual(JSObject* object, ExecState* exec, PropertyName propertyName, JSValue value, unsigned attributes)
 209 {
 210     JSActivation* thisObject = jsCast<JSActivation*>(object);
 211     ASSERT(!Heap::heap(value) || Heap::heap(value) == Heap::heap(thisObject));
 212
 213     if (thisObject->symbolTablePutWithAttributes(exec->vm(), propertyName, value, attributes))
 214         return;
 215
 216     // We don't call through to JSObject because __proto__ and getter/setter
 217     // properties are non-standard extensions that other implementations do not
 218     // expose in the activation object.
 219     ASSERT(!thisObject->hasGetterSetterProperties());
 220     JSObject::putDirectVirtual(thisObject, exec, propertyName, value, attributes);
 221 }
 222
 223 bool JSActivation::deleteProperty(JSCell* cell, ExecState* exec, PropertyName propertyName)
 224 {
 225     if (propertyName == exec->propertyNames().arguments)
 226         return false;
 227
 228     return Base::deleteProperty(cell, exec, propertyName);
 229 }
 230
 231 JSObject* JSActivation::toThisObject(JSCell*, ExecState* exec)
 232 {
 233     return exec->globalThisValue();
 234 }
 235
 236 JSValue JSActivation::argumentsGetter(ExecState*, JSValue slotBase, PropertyName)
 237 {
 238     JSActivation* activation = jsCast<JSActivation*>(slotBase);
 239     if (activation->isTornOff())
 240         return jsUndefined();
 241
 242     CallFrame* callFrame = CallFrame::create(reinterpret_cast<Register*>(activation->m_registers));
 243     int argumentsRegister = callFrame->codeBlock()->argumentsRegister();
 244     if (JSValue arguments = callFrame->uncheckedR(argumentsRegister).jsValue())
 245         return arguments;
 246     int realArgumentsRegister = unmodifiedArgumentsRegister(argumentsRegister);
 247
 248     JSValue arguments = JSValue(Arguments::create(callFrame->vm(), callFrame));
 249     callFrame->uncheckedR(argumentsRegister) = arguments;
 250     callFrame->uncheckedR(realArgumentsRegister) = arguments;
 251
 252     ASSERT(callFrame->uncheckedR(realArgumentsRegister).jsValue().inherits(&Arguments::s_info));
 253     return callFrame->uncheckedR(realArgumentsRegister).jsValue();
 254 }
 255
 256 // These two functions serve the purpose of isolating the common case from a
 257 // PIC branch.
 258
 259 PropertySlot::GetValueFunc JSActivation::getArgumentsGetter()
 260 {
 261     return argumentsGetter;
 262 }
 263
 264 } // namespace JSC