interpreter/CallFrame.h

   1 /*
   2  *  Copyright (C) 1999-2001 Harri Porten (porten@kde.org)
   3  *  Copyright (C) 2001 Peter Kelly (pmk@post.com)
   4  *  Copyright (C) 2003, 2007, 2008, 2011 Apple Inc. All rights reserved.
   5  *
   6  *  This library is free software; you can redistribute it and/or
   7  *  modify it under the terms of the GNU Library General Public
   8  *  License as published by the Free Software Foundation; either
   9  *  version 2 of the License, or (at your option) any later version.
  10  *
  11  *  This library is distributed in the hope that it will be useful,
  12  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  *  Library General Public License for more details.
  15  *
  16  *  You should have received a copy of the GNU Library General Public License
  17  *  along with this library; see the file COPYING.LIB.  If not, write to
  18  *  the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  19  *  Boston, MA 02110-1301, USA.
  20  *
  21  */
  22
  23 #ifndef CallFrame_h
  24 #define CallFrame_h
  25
  26 #include "JSGlobalData.h"
  27 #include "MacroAssemblerCodeRef.h"
  28 #include "RegisterFile.h"
  29
  30 namespace JSC  {
  31
  32     class Arguments;
  33     class JSActivation;
  34     class Interpreter;
  35     class ScopeChainNode;
  36
  37     // Represents the current state of script execution.
  38     // Passed as the first argument to most functions.
  39     class ExecState : private Register {
  40     public:
  41         JSObject* callee() const { return this[RegisterFile::Callee].function(); }
  42         CodeBlock* codeBlock() const { return this[RegisterFile::CodeBlock].Register::codeBlock(); }
  43         ScopeChainNode* scopeChain() const
  44         {
  45             ASSERT(this[RegisterFile::ScopeChain].Register::scopeChain());
  46             return this[RegisterFile::ScopeChain].Register::scopeChain();
  47         }
  48
  49         // Global object in which execution began.
  50         JSGlobalObject* dynamicGlobalObject();
  51
  52         // Global object in which the currently executing code was defined.
  53         // Differs from dynamicGlobalObject() during function calls across web browser frames.
  54         inline JSGlobalObject* lexicalGlobalObject() const;
  55
  56         // Differs from lexicalGlobalObject because this will have DOM window shell rather than
  57         // the actual DOM window, which can't be "this" for security reasons.
  58         inline JSObject* globalThisValue() const;
  59
  60         inline JSGlobalData& globalData() const;
  61
  62         // Convenience functions for access to global data.
  63         // It takes a few memory references to get from a call frame to the global data
  64         // pointer, so these are inefficient, and should be used sparingly in new code.
  65         // But they're used in many places in legacy code, so they're not going away any time soon.
  66
  67         void clearException() { globalData().exception = JSValue(); }
  68         JSValue exception() const { return globalData().exception; }
  69         bool hadException() const { return globalData().exception; }
  70
  71         const CommonIdentifiers& propertyNames() const { return *globalData().propertyNames; }
  72         const MarkedArgumentBuffer& emptyList() const { return *globalData().emptyList; }
  73         Interpreter* interpreter() { return globalData().interpreter; }
  74         Heap* heap() { return &globalData().heap; }
  75 #ifndef NDEBUG
  76         void dumpCaller();
  77 #endif
  78         static const HashTable* arrayConstructorTable(CallFrame* callFrame) { return callFrame->globalData().arrayConstructorTable; }
  79         static const HashTable* arrayPrototypeTable(CallFrame* callFrame) { return callFrame->globalData().arrayPrototypeTable; }
  80         static const HashTable* booleanPrototypeTable(CallFrame* callFrame) { return callFrame->globalData().booleanPrototypeTable; }
  81         static const HashTable* dateTable(CallFrame* callFrame) { return callFrame->globalData().dateTable; }
  82         static const HashTable* dateConstructorTable(CallFrame* callFrame) { return callFrame->globalData().dateConstructorTable; }
  83         static const HashTable* errorPrototypeTable(CallFrame* callFrame) { return callFrame->globalData().errorPrototypeTable; }
  84         static const HashTable* globalObjectTable(CallFrame* callFrame) { return callFrame->globalData().globalObjectTable; }
  85         static const HashTable* jsonTable(CallFrame* callFrame) { return callFrame->globalData().jsonTable; }
  86         static const HashTable* mathTable(CallFrame* callFrame) { return callFrame->globalData().mathTable; }
  87         static const HashTable* numberConstructorTable(CallFrame* callFrame) { return callFrame->globalData().numberConstructorTable; }
  88         static const HashTable* numberPrototypeTable(CallFrame* callFrame) { return callFrame->globalData().numberPrototypeTable; }
  89         static const HashTable* objectConstructorTable(CallFrame* callFrame) { return callFrame->globalData().objectConstructorTable; }
  90         static const HashTable* objectPrototypeTable(CallFrame* callFrame) { return callFrame->globalData().objectPrototypeTable; }
  91         static const HashTable* regExpTable(CallFrame* callFrame) { return callFrame->globalData().regExpTable; }
  92         static const HashTable* regExpConstructorTable(CallFrame* callFrame) { return callFrame->globalData().regExpConstructorTable; }
  93         static const HashTable* regExpPrototypeTable(CallFrame* callFrame) { return callFrame->globalData().regExpPrototypeTable; }
  94         static const HashTable* stringTable(CallFrame* callFrame) { return callFrame->globalData().stringTable; }
  95         static const HashTable* stringConstructorTable(CallFrame* callFrame) { return callFrame->globalData().stringConstructorTable; }
  96
  97         static CallFrame* create(Register* callFrameBase) { return static_cast<CallFrame*>(callFrameBase); }
  98         Register* registers() { return this; }
  99
 100         CallFrame& operator=(const Register& r) { *static_cast<Register*>(this) = r; return *this; }
 101
 102         CallFrame* callerFrame() const { return this[RegisterFile::CallerFrame].callFrame(); }
 103 #if ENABLE(JIT)
 104         ReturnAddressPtr returnPC() const { return ReturnAddressPtr(this[RegisterFile::ReturnPC].vPC()); }
 105 #endif
 106 #if ENABLE(INTERPRETER)
 107         Instruction* returnVPC() const { return this[RegisterFile::ReturnPC].vPC(); }
 108 #endif
 109
 110         void setCallerFrame(CallFrame* callerFrame) { static_cast<Register*>(this)[RegisterFile::CallerFrame] = callerFrame; }
 111         void setScopeChain(ScopeChainNode* scopeChain) { static_cast<Register*>(this)[RegisterFile::ScopeChain] = scopeChain; }
 112
 113         ALWAYS_INLINE void init(CodeBlock* codeBlock, Instruction* vPC, ScopeChainNode* scopeChain,
 114             CallFrame* callerFrame, int argc, JSObject* callee)
 115         {
 116             ASSERT(callerFrame); // Use noCaller() rather than 0 for the outer host call frame caller.
 117             ASSERT(callerFrame == noCaller() || callerFrame->removeHostCallFrameFlag()->registerFile()->end() >= this);
 118
 119             setCodeBlock(codeBlock);
 120             setScopeChain(scopeChain);
 121             setCallerFrame(callerFrame);
 122             setReturnPC(vPC); // This is either an Instruction* or a pointer into JIT generated code stored as an Instruction*.
 123             setArgumentCountIncludingThis(argc); // original argument count (for the sake of the "arguments" object)
 124             setCallee(callee);
 125         }
 126
 127         // Read a register from the codeframe (or constant from the CodeBlock).
 128         inline Register& r(int);
 129         // Read a register for a non-constant
 130         inline Register& uncheckedR(int);
 131
 132         // Access to arguments.
 133         int hostThisRegister() { return -RegisterFile::CallFrameHeaderSize - argumentCountIncludingThis(); }
 134         JSValue hostThisValue() { return this[hostThisRegister()].jsValue(); }
 135         size_t argumentCount() const { return argumentCountIncludingThis() - 1; }
 136         size_t argumentCountIncludingThis() const { return this[RegisterFile::ArgumentCount].i(); }
 137         JSValue argument(int argumentNumber)
 138         {
 139             int argumentIndex = -RegisterFile::CallFrameHeaderSize - this[RegisterFile::ArgumentCount].i() + argumentNumber + 1;
 140             if (argumentIndex >= -RegisterFile::CallFrameHeaderSize)
 141                 return jsUndefined();
 142             return this[argumentIndex].jsValue();
 143         }
 144
 145         static CallFrame* noCaller() { return reinterpret_cast<CallFrame*>(HostCallFrameFlag); }
 146
 147         bool hasHostCallFrameFlag() const { return reinterpret_cast<intptr_t>(this) & HostCallFrameFlag; }
 148         CallFrame* addHostCallFrameFlag() const { return reinterpret_cast<CallFrame*>(reinterpret_cast<intptr_t>(this) | HostCallFrameFlag); }
 149         CallFrame* removeHostCallFrameFlag() { return reinterpret_cast<CallFrame*>(reinterpret_cast<intptr_t>(this) & ~HostCallFrameFlag); }
 150
 151         void setArgumentCountIncludingThis(int count) { static_cast<Register*>(this)[RegisterFile::ArgumentCount] = Register::withInt(count); }
 152         void setCallee(JSObject* callee) { static_cast<Register*>(this)[RegisterFile::Callee] = Register::withCallee(callee); }
 153         void setCodeBlock(CodeBlock* codeBlock) { static_cast<Register*>(this)[RegisterFile::CodeBlock] = codeBlock; }
 154         void setReturnPC(void* value) { static_cast<Register*>(this)[RegisterFile::ReturnPC] = (Instruction*)value; }
 155
 156     private:
 157         static const intptr_t HostCallFrameFlag = 1;
 158 #ifndef NDEBUG
 159         RegisterFile* registerFile();
 160 #endif
 161         ExecState();
 162         ~ExecState();
 163     };
 164
 165 } // namespace JSC
 166
 167 #endif // CallFrame_h