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