runtime/Arguments.h

   1 /*
   2  *  Copyright (C) 1999-2000 Harri Porten (porten@kde.org)
   3  *  Copyright (C) 2003, 2006, 2007, 2008, 2009 Apple Inc. All rights reserved.
   4  *  Copyright (C) 2007 Cameron Zwarich (cwzwarich@uwaterloo.ca)
   5  *  Copyright (C) 2007 Maks Orlovich
   6  *
   7  *  This library is free software; you can redistribute it and/or
   8  *  modify it under the terms of the GNU Library General Public
   9  *  License as published by the Free Software Foundation; either
  10  *  version 2 of the License, or (at your option) any later version.
  11  *
  12  *  This library is distributed in the hope that it will be useful,
  13  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  *  Library General Public License for more details.
  16  *
  17  *  You should have received a copy of the GNU Library General Public License
  18  *  along with this library; see the file COPYING.LIB.  If not, write to
  19  *  the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  20  *  Boston, MA 02110-1301, USA.
  21  *
  22  */
  23
  24 #ifndef Arguments_h
  25 #define Arguments_h
  26
  27 #include "JSActivation.h"
  28 #include "JSFunction.h"
  29 #include "JSGlobalObject.h"
  30 #include "Interpreter.h"
  31 #include "ObjectConstructor.h"
  32 #include "PrototypeFunction.h"
  33
  34 namespace JSC {
  35
  36     struct ArgumentsData : Noncopyable {
  37         JSActivation* activation;
  38
  39         unsigned numParameters;
  40         ptrdiff_t firstParameterIndex;
  41         unsigned numArguments;
  42
  43         Register* registers;
  44         OwnArrayPtr<Register> registerArray;
  45
  46         Register* extraArguments;
  47         OwnArrayPtr<bool> deletedArguments;
  48         Register extraArgumentsFixedBuffer[4];
  49
  50         JSFunction* callee;
  51         bool overrodeLength : 1;
  52         bool overrodeCallee : 1;
  53     };
  54
  55
  56     class Arguments : public JSObject {
  57     public:
  58         // Use an enum because otherwise gcc insists on doing a memory
  59         // read.
  60         enum { MaxArguments = 0x10000 };
  61
  62         enum NoParametersType { NoParameters };
  63
  64         Arguments(CallFrame*);
  65         Arguments(CallFrame*, NoParametersType);
  66         virtual ~Arguments();
  67
  68         static const ClassInfo info;
  69
  70         virtual void markChildren(MarkStack&);
  71
  72         void fillArgList(ExecState*, MarkedArgumentBuffer&);
  73
  74         uint32_t numProvidedArguments(ExecState* exec) const
  75         {
  76             if (UNLIKELY(d->overrodeLength))
  77                 return get(exec, exec->propertyNames().length).toUInt32(exec);
  78             return d->numArguments;
  79         }
  80
  81         void copyToRegisters(ExecState* exec, Register* buffer, uint32_t maxSize);
  82         void copyRegisters();
  83         bool isTornOff() const { return d->registerArray; }
  84         void setActivation(JSActivation* activation)
  85         {
  86             d->activation = activation;
  87             d->registers = &activation->registerAt(0);
  88         }
  89
  90         static PassRefPtr<Structure> createStructure(JSValue prototype)
  91         {
  92             return Structure::create(prototype, TypeInfo(ObjectType, StructureFlags), AnonymousSlotCount);
  93         }
  94
  95     protected:
  96         static const unsigned StructureFlags = OverridesGetOwnPropertySlot | OverridesMarkChildren | OverridesGetPropertyNames | JSObject::StructureFlags;
  97
  98     private:
  99         void getArgumentsData(CallFrame*, JSFunction*&, ptrdiff_t& firstParameterIndex, Register*& argv, int& argc);
 100         virtual bool getOwnPropertySlot(ExecState*, const Identifier& propertyName, PropertySlot&);
 101         virtual bool getOwnPropertySlot(ExecState*, unsigned propertyName, PropertySlot&);
 102         virtual bool getOwnPropertyDescriptor(ExecState*, const Identifier&, PropertyDescriptor&);
 103         virtual void getOwnPropertyNames(ExecState*, PropertyNameArray&, EnumerationMode mode = ExcludeDontEnumProperties);
 104         virtual void put(ExecState*, const Identifier& propertyName, JSValue, PutPropertySlot&);
 105         virtual void put(ExecState*, unsigned propertyName, JSValue, PutPropertySlot&);
 106         virtual bool deleteProperty(ExecState*, const Identifier& propertyName);
 107         virtual bool deleteProperty(ExecState*, unsigned propertyName);
 108
 109         virtual const ClassInfo* classInfo() const { return &info; }
 110
 111         void init(CallFrame*);
 112
 113         OwnPtr<ArgumentsData> d;
 114     };
 115
 116     Arguments* asArguments(JSValue);
 117
 118     inline Arguments* asArguments(JSValue value)
 119     {
 120         ASSERT(asObject(value)->inherits(&Arguments::info));
 121         return static_cast<Arguments*>(asObject(value));
 122     }
 123
 124     ALWAYS_INLINE void Arguments::getArgumentsData(CallFrame* callFrame, JSFunction*& function, ptrdiff_t& firstParameterIndex, Register*& argv, int& argc)
 125     {
 126         function = callFrame->callee();
 127
 128         int numParameters = function->jsExecutable()->parameterCount();
 129         argc = callFrame->argumentCount();
 130
 131         if (argc <= numParameters)
 132             argv = callFrame->registers() - RegisterFile::CallFrameHeaderSize - numParameters;
 133         else
 134             argv = callFrame->registers() - RegisterFile::CallFrameHeaderSize - numParameters - argc;
 135
 136         argc -= 1; // - 1 to skip "this"
 137         firstParameterIndex = -RegisterFile::CallFrameHeaderSize - numParameters;
 138     }
 139
 140     inline Arguments::Arguments(CallFrame* callFrame)
 141         : JSObject(callFrame->lexicalGlobalObject()->argumentsStructure())
 142         , d(new ArgumentsData)
 143     {
 144         JSFunction* callee;
 145         ptrdiff_t firstParameterIndex;
 146         Register* argv;
 147         int numArguments;
 148         getArgumentsData(callFrame, callee, firstParameterIndex, argv, numArguments);
 149
 150         d->numParameters = callee->jsExecutable()->parameterCount();
 151         d->firstParameterIndex = firstParameterIndex;
 152         d->numArguments = numArguments;
 153
 154         d->activation = 0;
 155         d->registers = callFrame->registers();
 156
 157         Register* extraArguments;
 158         if (d->numArguments <= d->numParameters)
 159             extraArguments = 0;
 160         else {
 161             unsigned numExtraArguments = d->numArguments - d->numParameters;
 162             if (numExtraArguments > sizeof(d->extraArgumentsFixedBuffer) / sizeof(Register))
 163                 extraArguments = new Register[numExtraArguments];
 164             else
 165                 extraArguments = d->extraArgumentsFixedBuffer;
 166             for (unsigned i = 0; i < numExtraArguments; ++i)
 167                 extraArguments[i] = argv[d->numParameters + i];
 168         }
 169
 170         d->extraArguments = extraArguments;
 171
 172         d->callee = callee;
 173         d->overrodeLength = false;
 174         d->overrodeCallee = false;
 175     }
 176
 177     inline Arguments::Arguments(CallFrame* callFrame, NoParametersType)
 178         : JSObject(callFrame->lexicalGlobalObject()->argumentsStructure())
 179         , d(new ArgumentsData)
 180     {
 181         ASSERT(!callFrame->callee()->jsExecutable()->parameterCount());
 182
 183         unsigned numArguments = callFrame->argumentCount() - 1;
 184
 185         d->numParameters = 0;
 186         d->numArguments = numArguments;
 187         d->activation = 0;
 188
 189         Register* extraArguments;
 190         if (numArguments > sizeof(d->extraArgumentsFixedBuffer) / sizeof(Register))
 191             extraArguments = new Register[numArguments];
 192         else
 193             extraArguments = d->extraArgumentsFixedBuffer;
 194
 195         Register* argv = callFrame->registers() - RegisterFile::CallFrameHeaderSize - numArguments - 1;
 196         for (unsigned i = 0; i < numArguments; ++i)
 197             extraArguments[i] = argv[i];
 198
 199         d->extraArguments = extraArguments;
 200
 201         d->callee = callFrame->callee();
 202         d->overrodeLength = false;
 203         d->overrodeCallee = false;
 204     }
 205
 206     inline void Arguments::copyRegisters()
 207     {
 208         ASSERT(!isTornOff());
 209
 210         if (!d->numParameters)
 211             return;
 212
 213         int registerOffset = d->numParameters + RegisterFile::CallFrameHeaderSize;
 214         size_t registerArraySize = d->numParameters;
 215
 216         Register* registerArray = new Register[registerArraySize];
 217         memcpy(registerArray, d->registers - registerOffset, registerArraySize * sizeof(Register));
 218         d->registerArray.set(registerArray);
 219         d->registers = registerArray + registerOffset;
 220     }
 221
 222     // This JSActivation function is defined here so it can get at Arguments::setRegisters.
 223     inline void JSActivation::copyRegisters(Arguments* arguments)
 224     {
 225         ASSERT(!d()->registerArray);
 226
 227         size_t numParametersMinusThis = d()->functionExecutable->generatedBytecode().m_numParameters - 1;
 228         size_t numVars = d()->functionExecutable->generatedBytecode().m_numVars;
 229         size_t numLocals = numVars + numParametersMinusThis;
 230
 231         if (!numLocals)
 232             return;
 233
 234         int registerOffset = numParametersMinusThis + RegisterFile::CallFrameHeaderSize;
 235         size_t registerArraySize = numLocals + RegisterFile::CallFrameHeaderSize;
 236
 237         Register* registerArray = copyRegisterArray(d()->registers - registerOffset, registerArraySize);
 238         setRegisters(registerArray + registerOffset, registerArray);
 239         if (arguments && !arguments->isTornOff())
 240             static_cast<Arguments*>(arguments)->setActivation(this);
 241     }
 242
 243     ALWAYS_INLINE Arguments* Register::arguments() const
 244     {
 245         if (jsValue() == JSValue())
 246             return 0;
 247         return asArguments(jsValue());
 248     }
 249
 250
 251 } // namespace JSC
 252
 253 #endif // Arguments_h