summaryrefslogtreecommitdiffstats
path: root/JavaScriptCore/runtime/Arguments.h
blob: 6bb180c7201f370aadb59207d6e5d5acad00690a (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
/*
 *  Copyright (C) 1999-2000 Harri Porten (porten@kde.org)
 *  Copyright (C) 2003, 2006, 2007, 2008, 2009 Apple Inc. All rights reserved.
 *  Copyright (C) 2007 Cameron Zwarich (cwzwarich@uwaterloo.ca)
 *  Copyright (C) 2007 Maks Orlovich
 *
 *  This library is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Library General Public
 *  License as published by the Free Software Foundation; either
 *  version 2 of the License, or (at your option) any later version.
 *
 *  This library is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 *  Library General Public License for more details.
 *
 *  You should have received a copy of the GNU Library General Public License
 *  along with this library; see the file COPYING.LIB.  If not, write to
 *  the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 *  Boston, MA 02110-1301, USA.
 *
 */

#ifndef Arguments_h
#define Arguments_h

#include "JSActivation.h"
#include "JSFunction.h"
#include "JSGlobalObject.h"
#include "Interpreter.h"
#include "ObjectConstructor.h"
#include "PrototypeFunction.h"

namespace JSC {

    struct ArgumentsData : Noncopyable {
        JSActivation* activation;

        unsigned numParameters;
        ptrdiff_t firstParameterIndex;
        unsigned numArguments;

        Register* registers;
        OwnArrayPtr<Register> registerArray;

        Register* extraArguments;
        OwnArrayPtr<bool> deletedArguments;
        Register extraArgumentsFixedBuffer[4];

        JSFunction* callee;
        bool overrodeLength : 1;
        bool overrodeCallee : 1;
    };


    class Arguments : public JSObject {
    public:
        // Use an enum because otherwise gcc insists on doing a memory
        // read.
        enum { MaxArguments = 0x10000 };

        enum NoParametersType { NoParameters };

        Arguments(CallFrame*);
        Arguments(CallFrame*, NoParametersType);
        virtual ~Arguments();

        static const ClassInfo info;

        virtual void markChildren(MarkStack&);

        void fillArgList(ExecState*, MarkedArgumentBuffer&);

        uint32_t numProvidedArguments(ExecState* exec) const 
        {
            if (UNLIKELY(d->overrodeLength))
                return get(exec, exec->propertyNames().length).toUInt32(exec);
            return d->numArguments; 
        }
        
        void copyToRegisters(ExecState* exec, Register* buffer, uint32_t maxSize);
        void copyRegisters();
        bool isTornOff() const { return d->registerArray; }
        void setActivation(JSActivation* activation)
        {
            d->activation = activation;
            d->registers = &activation->registerAt(0);
        }

        static PassRefPtr<Structure> createStructure(JSValue prototype) 
        { 
            return Structure::create(prototype, TypeInfo(ObjectType, StructureFlags), AnonymousSlotCount); 
        }

    protected:
        static const unsigned StructureFlags = OverridesGetOwnPropertySlot | OverridesMarkChildren | OverridesGetPropertyNames | JSObject::StructureFlags;

    private:
        void getArgumentsData(CallFrame*, JSFunction*&, ptrdiff_t& firstParameterIndex, Register*& argv, int& argc);
        virtual bool getOwnPropertySlot(ExecState*, const Identifier& propertyName, PropertySlot&);
        virtual bool getOwnPropertySlot(ExecState*, unsigned propertyName, PropertySlot&);
        virtual bool getOwnPropertyDescriptor(ExecState*, const Identifier&, PropertyDescriptor&);
        virtual void getOwnPropertyNames(ExecState*, PropertyNameArray&, EnumerationMode mode = ExcludeDontEnumProperties);
        virtual void put(ExecState*, const Identifier& propertyName, JSValue, PutPropertySlot&);
        virtual void put(ExecState*, unsigned propertyName, JSValue, PutPropertySlot&);
        virtual bool deleteProperty(ExecState*, const Identifier& propertyName);
        virtual bool deleteProperty(ExecState*, unsigned propertyName);

        virtual const ClassInfo* classInfo() const { return &info; }

        void init(CallFrame*);

        OwnPtr<ArgumentsData> d;
    };

    Arguments* asArguments(JSValue);

    inline Arguments* asArguments(JSValue value)
    {
        ASSERT(asObject(value)->inherits(&Arguments::info));
        return static_cast<Arguments*>(asObject(value));
    }

    ALWAYS_INLINE void Arguments::getArgumentsData(CallFrame* callFrame, JSFunction*& function, ptrdiff_t& firstParameterIndex, Register*& argv, int& argc)
    {
        function = asFunction(callFrame->callee());

        int numParameters = function->jsExecutable()->parameterCount();
        argc = callFrame->argumentCountIncludingThis();

        if (argc <= numParameters)
            argv = callFrame->registers() - RegisterFile::CallFrameHeaderSize - numParameters;
        else
            argv = callFrame->registers() - RegisterFile::CallFrameHeaderSize - numParameters - argc;

        argc -= 1; // - 1 to skip "this"
        firstParameterIndex = -RegisterFile::CallFrameHeaderSize - numParameters;
    }

    inline Arguments::Arguments(CallFrame* callFrame)
        : JSObject(callFrame->lexicalGlobalObject()->argumentsStructure())
        , d(new ArgumentsData)
    {
        JSFunction* callee;
        ptrdiff_t firstParameterIndex;
        Register* argv;
        int numArguments;
        getArgumentsData(callFrame, callee, firstParameterIndex, argv, numArguments);

        d->numParameters = callee->jsExecutable()->parameterCount();
        d->firstParameterIndex = firstParameterIndex;
        d->numArguments = numArguments;

        d->activation = 0;
        d->registers = callFrame->registers();

        Register* extraArguments;
        if (d->numArguments <= d->numParameters)
            extraArguments = 0;
        else {
            unsigned numExtraArguments = d->numArguments - d->numParameters;
            if (numExtraArguments > sizeof(d->extraArgumentsFixedBuffer) / sizeof(Register))
                extraArguments = new Register[numExtraArguments];
            else
                extraArguments = d->extraArgumentsFixedBuffer;
            for (unsigned i = 0; i < numExtraArguments; ++i)
                extraArguments[i] = argv[d->numParameters + i];
        }

        d->extraArguments = extraArguments;

        d->callee = callee;
        d->overrodeLength = false;
        d->overrodeCallee = false;
    }

    inline Arguments::Arguments(CallFrame* callFrame, NoParametersType)
        : JSObject(callFrame->lexicalGlobalObject()->argumentsStructure())
        , d(new ArgumentsData)
    {
        ASSERT(!asFunction(callFrame->callee())->jsExecutable()->parameterCount());

        unsigned numArguments = callFrame->argumentCount();

        d->numParameters = 0;
        d->numArguments = numArguments;
        d->activation = 0;

        Register* extraArguments;
        if (numArguments > sizeof(d->extraArgumentsFixedBuffer) / sizeof(Register))
            extraArguments = new Register[numArguments];
        else
            extraArguments = d->extraArgumentsFixedBuffer;

        Register* argv = callFrame->registers() - RegisterFile::CallFrameHeaderSize - numArguments - 1;
        for (unsigned i = 0; i < numArguments; ++i)
            extraArguments[i] = argv[i];

        d->extraArguments = extraArguments;

        d->callee = asFunction(callFrame->callee());
        d->overrodeLength = false;
        d->overrodeCallee = false;
    }

    inline void Arguments::copyRegisters()
    {
        ASSERT(!isTornOff());

        if (!d->numParameters)
            return;

        int registerOffset = d->numParameters + RegisterFile::CallFrameHeaderSize;
        size_t registerArraySize = d->numParameters;

        Register* registerArray = new Register[registerArraySize];
        memcpy(registerArray, d->registers - registerOffset, registerArraySize * sizeof(Register));
        d->registerArray.set(registerArray);
        d->registers = registerArray + registerOffset;
    }

    // This JSActivation function is defined here so it can get at Arguments::setRegisters.
    inline void JSActivation::copyRegisters()
    {
        ASSERT(!d()->registerArray);

        size_t numParametersMinusThis = d()->functionExecutable->parameterCount();
        size_t numVars = d()->functionExecutable->variableCount();
        size_t numLocals = numVars + numParametersMinusThis;

        if (!numLocals)
            return;

        int registerOffset = numParametersMinusThis + RegisterFile::CallFrameHeaderSize;
        size_t registerArraySize = numLocals + RegisterFile::CallFrameHeaderSize;

        Register* registerArray = copyRegisterArray(d()->registers - registerOffset, registerArraySize);
        setRegisters(registerArray + registerOffset, registerArray);
    }

} // namespace JSC

#endif // Arguments_h