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         enum NoParametersType { NoParameters };
  59
  60         Arguments(CallFrame*);
  61         Arguments(CallFrame*, NoParametersType);
  62         virtual ~Arguments();
  63
  64         static const ClassInfo info;
  65
  66         virtual void markChildren(MarkStack&);
  67
  68         void fillArgList(ExecState*, MarkedArgumentBuffer&);
  69
  70         uint32_t numProvidedArguments(ExecState* exec) const
  71         {
  72             if (UNLIKELY(d->overrodeLength))
  73                 return get(exec, exec->propertyNames().length).toUInt32(exec);
  74             return d->numArguments;
  75         }
  76
  77         void copyToRegisters(ExecState* exec, Register* buffer, uint32_t maxSize);
  78         void copyRegisters();
  79         bool isTornOff() const { return d->registerArray; }
  80         void setActivation(JSActivation* activation)
  81         {
  82             d->activation = activation;
  83             d->registers = &activation->registerAt(0);
  84         }
  85
  86         static PassRefPtr<Structure> createStructure(JSValue prototype)
  87         {
  88             return Structure::create(prototype, TypeInfo(ObjectType, StructureFlags), AnonymousSlotCount);
  89         }
  90
  91     protected:
  92         static const unsigned StructureFlags = OverridesGetOwnPropertySlot | OverridesMarkChildren | OverridesGetPropertyNames | JSObject::StructureFlags;
  93
  94     private:
  95         void getArgumentsData(CallFrame*, JSFunction*&, ptrdiff_t& firstParameterIndex, Register*& argv, int& argc);
  96         virtual bool getOwnPropertySlot(ExecState*, const Identifier& propertyName, PropertySlot&);
  97         virtual bool getOwnPropertySlot(ExecState*, unsigned propertyName, PropertySlot&);
  98         virtual bool getOwnPropertyDescriptor(ExecState*, const Identifier&, PropertyDescriptor&);
  99         virtual void getOwnPropertyNames(ExecState*, PropertyNameArray&, EnumerationMode mode = ExcludeDontEnumProperties);
 100         virtual void put(ExecState*, const Identifier& propertyName, JSValue, PutPropertySlot&);
 101         virtual void put(ExecState*, unsigned propertyName, JSValue, PutPropertySlot&);
 102         virtual bool deleteProperty(ExecState*, const Identifier& propertyName);
 103         virtual bool deleteProperty(ExecState*, unsigned propertyName);
 104
 105         virtual const ClassInfo* classInfo() const { return &info; }
 106
 107         void init(CallFrame*);
 108
 109         OwnPtr<ArgumentsData> d;
 110     };
 111
 112     Arguments* asArguments(JSValue);
 113
 114     inline Arguments* asArguments(JSValue value)
 115     {
 116         ASSERT(asObject(value)->inherits(&Arguments::info));
 117         return static_cast<Arguments*>(asObject(value));
 118     }
 119
 120     ALWAYS_INLINE void Arguments::getArgumentsData(CallFrame* callFrame, JSFunction*& function, ptrdiff_t& firstParameterIndex, Register*& argv, int& argc)
 121     {
 122         function = callFrame->callee();
 123
 124         int numParameters = function->jsExecutable()->parameterCount();
 125         argc = callFrame->argumentCount();
 126
 127         if (argc <= numParameters)
 128             argv = callFrame->registers() - RegisterFile::CallFrameHeaderSize - numParameters;
 129         else
 130             argv = callFrame->registers() - RegisterFile::CallFrameHeaderSize - numParameters - argc;
 131
 132         argc -= 1; // - 1 to skip "this"
 133         firstParameterIndex = -RegisterFile::CallFrameHeaderSize - numParameters;
 134     }
 135
 136     inline Arguments::Arguments(CallFrame* callFrame)
 137         : JSObject(callFrame->lexicalGlobalObject()->argumentsStructure())
 138         , d(new ArgumentsData)
 139     {
 140         JSFunction* callee;
 141         ptrdiff_t firstParameterIndex;
 142         Register* argv;
 143         int numArguments;
 144         getArgumentsData(callFrame, callee, firstParameterIndex, argv, numArguments);
 145
 146         d->numParameters = callee->jsExecutable()->parameterCount();
 147         d->firstParameterIndex = firstParameterIndex;
 148         d->numArguments = numArguments;
 149
 150         d->activation = 0;
 151         d->registers = callFrame->registers();
 152
 153         Register* extraArguments;
 154         if (d->numArguments <= d->numParameters)
 155             extraArguments = 0;
 156         else {
 157             unsigned numExtraArguments = d->numArguments - d->numParameters;
 158             if (numExtraArguments > sizeof(d->extraArgumentsFixedBuffer) / sizeof(Register))
 159                 extraArguments = new Register[numExtraArguments];
 160             else
 161                 extraArguments = d->extraArgumentsFixedBuffer;
 162             for (unsigned i = 0; i < numExtraArguments; ++i)
 163                 extraArguments[i] = argv[d->numParameters + i];
 164         }
 165
 166         d->extraArguments = extraArguments;
 167
 168         d->callee = callee;
 169         d->overrodeLength = false;
 170         d->overrodeCallee = false;
 171     }
 172
 173     inline Arguments::Arguments(CallFrame* callFrame, NoParametersType)
 174         : JSObject(callFrame->lexicalGlobalObject()->argumentsStructure())
 175         , d(new ArgumentsData)
 176     {
 177         ASSERT(!callFrame->callee()->jsExecutable()->parameterCount());
 178
 179         unsigned numArguments = callFrame->argumentCount() - 1;
 180
 181         d->numParameters = 0;
 182         d->numArguments = numArguments;
 183         d->activation = 0;
 184
 185         Register* extraArguments;
 186         if (numArguments > sizeof(d->extraArgumentsFixedBuffer) / sizeof(Register))
 187             extraArguments = new Register[numArguments];
 188         else
 189             extraArguments = d->extraArgumentsFixedBuffer;
 190
 191         Register* argv = callFrame->registers() - RegisterFile::CallFrameHeaderSize - numArguments - 1;
 192         for (unsigned i = 0; i < numArguments; ++i)
 193             extraArguments[i] = argv[i];
 194
 195         d->extraArguments = extraArguments;
 196
 197         d->callee = callFrame->callee();
 198         d->overrodeLength = false;
 199         d->overrodeCallee = false;
 200     }
 201
 202     inline void Arguments::copyRegisters()
 203     {
 204         ASSERT(!isTornOff());
 205
 206         if (!d->numParameters)
 207             return;
 208
 209         int registerOffset = d->numParameters + RegisterFile::CallFrameHeaderSize;
 210         size_t registerArraySize = d->numParameters;
 211
 212         Register* registerArray = new Register[registerArraySize];
 213         memcpy(registerArray, d->registers - registerOffset, registerArraySize * sizeof(Register));
 214         d->registerArray.set(registerArray);
 215         d->registers = registerArray + registerOffset;
 216     }
 217
 218     // This JSActivation function is defined here so it can get at Arguments::setRegisters.
 219     inline void JSActivation::copyRegisters(Arguments* arguments)
 220     {
 221         ASSERT(!d()->registerArray);
 222
 223         size_t numParametersMinusThis = d()->functionExecutable->generatedBytecode().m_numParameters - 1;
 224         size_t numVars = d()->functionExecutable->generatedBytecode().m_numVars;
 225         size_t numLocals = numVars + numParametersMinusThis;
 226
 227         if (!numLocals)
 228             return;
 229
 230         int registerOffset = numParametersMinusThis + RegisterFile::CallFrameHeaderSize;
 231         size_t registerArraySize = numLocals + RegisterFile::CallFrameHeaderSize;
 232
 233         Register* registerArray = copyRegisterArray(d()->registers - registerOffset, registerArraySize);
 234         setRegisters(registerArray + registerOffset, registerArray);
 235         if (arguments && !arguments->isTornOff())
 236             static_cast<Arguments*>(arguments)->setActivation(this);
 237     }
 238
 239     ALWAYS_INLINE Arguments* Register::arguments() const
 240     {
 241         if (jsValue() == JSValue())
 242             return 0;
 243         return asArguments(jsValue());
 244     }
 245
 246
 247 } // namespace JSC
 248
 249 #endif // Arguments_h