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 "AbstractPC.h"
  27 #include "JSGlobalData.h"
  28 #include "MacroAssemblerCodeRef.h"
  29 #include "RegisterFile.h"
  30
  31 namespace JSC  {
  32
  33     class Arguments;
  34     class JSActivation;
  35     class Interpreter;
  36     class ScopeChainNode;
  37
  38     // Represents the current state of script execution.
  39     // Passed as the first argument to most functions.
  40     class ExecState : private Register {
  41     public:
  42         JSValue calleeAsValue() const { return this[RegisterFile::Callee].jsValue(); }
  43         JSObject* callee() const { return this[RegisterFile::Callee].function(); }
  44         CodeBlock* codeBlock() const { return this[RegisterFile::CodeBlock].Register::codeBlock(); }
  45         ScopeChainNode* scopeChain() const
  46         {
  47             ASSERT(this[RegisterFile::ScopeChain].Register::scopeChain());
  48             return this[RegisterFile::ScopeChain].Register::scopeChain();
  49         }
  50
  51         // Global object in which execution began.
  52         JSGlobalObject* dynamicGlobalObject();
  53
  54         // Global object in which the currently executing code was defined.
  55         // Differs from dynamicGlobalObject() during function calls across web browser frames.
  56         inline JSGlobalObject* lexicalGlobalObject() const;
  57
  58         // Differs from lexicalGlobalObject because this will have DOM window shell rather than
  59         // the actual DOM window, which can't be "this" for security reasons.
  60         inline JSObject* globalThisValue() const;
  61
  62         inline JSGlobalData& globalData() const;
  63
  64         // Convenience functions for access to global data.
  65         // It takes a few memory references to get from a call frame to the global data
  66         // pointer, so these are inefficient, and should be used sparingly in new code.
  67         // But they're used in many places in legacy code, so they're not going away any time soon.
  68
  69         void clearException() { globalData().exception = JSValue(); }
  70         JSValue exception() const { return globalData().exception; }
  71         bool hadException() const { return globalData().exception; }
  72
  73         const CommonIdentifiers& propertyNames() const { return *globalData().propertyNames; }
  74         const MarkedArgumentBuffer& emptyList() const { return *globalData().emptyList; }
  75         Interpreter* interpreter() { return globalData().interpreter; }
  76         Heap* heap() { return &globalData().heap; }
  77 #ifndef NDEBUG
  78         void dumpCaller();
  79 #endif
  80         static const HashTable* arrayConstructorTable(CallFrame* callFrame) { return callFrame->globalData().arrayConstructorTable; }
  81         static const HashTable* arrayPrototypeTable(CallFrame* callFrame) { return callFrame->globalData().arrayPrototypeTable; }
  82         static const HashTable* booleanPrototypeTable(CallFrame* callFrame) { return callFrame->globalData().booleanPrototypeTable; }
  83         static const HashTable* dateTable(CallFrame* callFrame) { return callFrame->globalData().dateTable; }
  84         static const HashTable* dateConstructorTable(CallFrame* callFrame) { return callFrame->globalData().dateConstructorTable; }
  85         static const HashTable* errorPrototypeTable(CallFrame* callFrame) { return callFrame->globalData().errorPrototypeTable; }
  86         static const HashTable* globalObjectTable(CallFrame* callFrame) { return callFrame->globalData().globalObjectTable; }
  87         static const HashTable* jsonTable(CallFrame* callFrame) { return callFrame->globalData().jsonTable; }
  88         static const HashTable* mathTable(CallFrame* callFrame) { return callFrame->globalData().mathTable; }
  89         static const HashTable* numberConstructorTable(CallFrame* callFrame) { return callFrame->globalData().numberConstructorTable; }
  90         static const HashTable* numberPrototypeTable(CallFrame* callFrame) { return callFrame->globalData().numberPrototypeTable; }
  91         static const HashTable* objectConstructorTable(CallFrame* callFrame) { return callFrame->globalData().objectConstructorTable; }
  92         static const HashTable* objectPrototypeTable(CallFrame* callFrame) { return callFrame->globalData().objectPrototypeTable; }
  93         static const HashTable* regExpTable(CallFrame* callFrame) { return callFrame->globalData().regExpTable; }
  94         static const HashTable* regExpConstructorTable(CallFrame* callFrame) { return callFrame->globalData().regExpConstructorTable; }
  95         static const HashTable* regExpPrototypeTable(CallFrame* callFrame) { return callFrame->globalData().regExpPrototypeTable; }
  96         static const HashTable* stringTable(CallFrame* callFrame) { return callFrame->globalData().stringTable; }
  97         static const HashTable* stringConstructorTable(CallFrame* callFrame) { return callFrame->globalData().stringConstructorTable; }
  98
  99         static CallFrame* create(Register* callFrameBase) { return static_cast<CallFrame*>(callFrameBase); }
 100         Register* registers() { return this; }
 101
 102         CallFrame& operator=(const Register& r) { *static_cast<Register*>(this) = r; return *this; }
 103
 104         CallFrame* callerFrame() const { return this[RegisterFile::CallerFrame].callFrame(); }
 105 #if ENABLE(JIT)
 106         ReturnAddressPtr returnPC() const { return ReturnAddressPtr(this[RegisterFile::ReturnPC].vPC()); }
 107         bool hasReturnPC() const { return !!this[RegisterFile::ReturnPC].vPC(); }
 108         void clearReturnPC() { registers()[RegisterFile::ReturnPC] = static_cast<Instruction*>(0); }
 109 #endif
 110         AbstractPC abstractReturnPC(JSGlobalData& globalData) { return AbstractPC(globalData, this); }
 111 #if USE(JSVALUE32_64)
 112         unsigned bytecodeOffsetForNonDFGCode() const;
 113         void setBytecodeOffsetForNonDFGCode(unsigned offset);
 114 #else
 115         unsigned bytecodeOffsetForNonDFGCode() const
 116         {
 117             ASSERT(codeBlock());
 118             return this[RegisterFile::ArgumentCount].tag();
 119         }
 120
 121         void setBytecodeOffsetForNonDFGCode(unsigned offset)
 122         {
 123             ASSERT(codeBlock());
 124             this[RegisterFile::ArgumentCount].tag() = static_cast<int32_t>(offset);
 125         }
 126 #endif
 127
 128         Register* frameExtent()
 129         {
 130             if (!codeBlock())
 131                 return registers();
 132             return frameExtentInternal();
 133         }
 134
 135         Register* frameExtentInternal();
 136
 137 #if ENABLE(DFG_JIT)
 138         InlineCallFrame* inlineCallFrame() const { return this[RegisterFile::ReturnPC].asInlineCallFrame(); }
 139         unsigned codeOriginIndexForDFG() const { return this[RegisterFile::ArgumentCount].tag(); }
 140 #else
 141         // This will never be called if !ENABLE(DFG_JIT) since all calls should be guarded by
 142         // isInlineCallFrame(). But to make it easier to write code without having a bunch of
 143         // #if's, we make a dummy implementation available anyway.
 144         InlineCallFrame* inlineCallFrame() const
 145         {
 146             ASSERT_NOT_REACHED();
 147             return 0;
 148         }
 149 #endif
 150 #if ENABLE(CLASSIC_INTERPRETER)
 151         Instruction* returnVPC() const { return this[RegisterFile::ReturnPC].vPC(); }
 152 #endif
 153 #if USE(JSVALUE32_64)
 154         Instruction* currentVPC() const
 155         {
 156             return bitwise_cast<Instruction*>(this[RegisterFile::ArgumentCount].tag());
 157         }
 158         void setCurrentVPC(Instruction* vpc)
 159         {
 160             this[RegisterFile::ArgumentCount].tag() = bitwise_cast<int32_t>(vpc);
 161         }
 162 #else
 163         Instruction* currentVPC() const;
 164         void setCurrentVPC(Instruction* vpc);
 165 #endif
 166
 167         void setCallerFrame(CallFrame* callerFrame) { static_cast<Register*>(this)[RegisterFile::CallerFrame] = callerFrame; }
 168         void setScopeChain(ScopeChainNode* scopeChain) { static_cast<Register*>(this)[RegisterFile::ScopeChain] = scopeChain; }
 169
 170         ALWAYS_INLINE void init(CodeBlock* codeBlock, Instruction* vPC, ScopeChainNode* scopeChain,
 171             CallFrame* callerFrame, int argc, JSObject* callee)
 172         {
 173             ASSERT(callerFrame); // Use noCaller() rather than 0 for the outer host call frame caller.
 174             ASSERT(callerFrame == noCaller() || callerFrame->removeHostCallFrameFlag()->registerFile()->end() >= this);
 175
 176             setCodeBlock(codeBlock);
 177             setScopeChain(scopeChain);
 178             setCallerFrame(callerFrame);
 179             setReturnPC(vPC); // This is either an Instruction* or a pointer into JIT generated code stored as an Instruction*.
 180             setArgumentCountIncludingThis(argc); // original argument count (for the sake of the "arguments" object)
 181             setCallee(callee);
 182         }
 183
 184         // Read a register from the codeframe (or constant from the CodeBlock).
 185         inline Register& r(int);
 186         // Read a register for a non-constant
 187         inline Register& uncheckedR(int);
 188
 189         // Access to arguments.
 190         size_t argumentCount() const { return argumentCountIncludingThis() - 1; }
 191         size_t argumentCountIncludingThis() const { return this[RegisterFile::ArgumentCount].payload(); }
 192         static int argumentOffset(size_t argument) { return s_firstArgumentOffset - argument; }
 193         static int argumentOffsetIncludingThis(size_t argument) { return s_thisArgumentOffset - argument; }
 194
 195         JSValue argument(size_t argument)
 196         {
 197             if (argument >= argumentCount())
 198                  return jsUndefined();
 199             return this[argumentOffset(argument)].jsValue();
 200         }
 201         void setArgument(size_t argument, JSValue value)
 202         {
 203             this[argumentOffset(argument)] = value;
 204         }
 205
 206         static int thisArgumentOffset() { return argumentOffsetIncludingThis(0); }
 207         JSValue thisValue() { return this[thisArgumentOffset()].jsValue(); }
 208         void setThisValue(JSValue value) { this[thisArgumentOffset()] = value; }
 209
 210         static int offsetFor(size_t argumentCountIncludingThis) { return argumentCountIncludingThis + RegisterFile::CallFrameHeaderSize; }
 211
 212         // FIXME: Remove these.
 213         int hostThisRegister() { return thisArgumentOffset(); }
 214         JSValue hostThisValue() { return thisValue(); }
 215
 216         static CallFrame* noCaller() { return reinterpret_cast<CallFrame*>(HostCallFrameFlag); }
 217
 218         bool hasHostCallFrameFlag() const { return reinterpret_cast<intptr_t>(this) & HostCallFrameFlag; }
 219         CallFrame* addHostCallFrameFlag() const { return reinterpret_cast<CallFrame*>(reinterpret_cast<intptr_t>(this) | HostCallFrameFlag); }
 220         CallFrame* removeHostCallFrameFlag() { return reinterpret_cast<CallFrame*>(reinterpret_cast<intptr_t>(this) & ~HostCallFrameFlag); }
 221
 222         void setArgumentCountIncludingThis(int count) { static_cast<Register*>(this)[RegisterFile::ArgumentCount].payload() = count; }
 223         void setCallee(JSObject* callee) { static_cast<Register*>(this)[RegisterFile::Callee] = Register::withCallee(callee); }
 224         void setCodeBlock(CodeBlock* codeBlock) { static_cast<Register*>(this)[RegisterFile::CodeBlock] = codeBlock; }
 225         void setReturnPC(void* value) { static_cast<Register*>(this)[RegisterFile::ReturnPC] = (Instruction*)value; }
 226
 227 #if ENABLE(DFG_JIT)
 228         bool isInlineCallFrame();
 229
 230         void setInlineCallFrame(InlineCallFrame* inlineCallFrame) { static_cast<Register*>(this)[RegisterFile::ReturnPC] = inlineCallFrame; }
 231
 232         // Call this to get the semantically correct JS CallFrame* for the
 233         // currently executing function.
 234         CallFrame* trueCallFrame(AbstractPC);
 235
 236         // Call this to get the semantically correct JS CallFrame* corresponding
 237         // to the caller. This resolves issues surrounding inlining and the
 238         // HostCallFrameFlag stuff.
 239         CallFrame* trueCallerFrame();
 240 #else
 241         bool isInlineCallFrame() { return false; }
 242
 243         CallFrame* trueCallFrame(AbstractPC) { return this; }
 244         CallFrame* trueCallerFrame() { return callerFrame()->removeHostCallFrameFlag(); }
 245 #endif
 246
 247         // Call this to get the true call frame (accounted for inlining and any
 248         // other optimizations), when you have entered into VM code through one
 249         // of the "blessed" entrypoints (JITStubs or DFGOperations). This means
 250         // that if you're pretty much anywhere in the VM you can safely call this;
 251         // though if you were to magically get an ExecState* by, say, interrupting
 252         // a thread that is running JS code and brutishly scraped the call frame
 253         // register, calling this method would probably lead to horrible things
 254         // happening.
 255         CallFrame* trueCallFrameFromVMCode() { return trueCallFrame(AbstractPC()); }
 256
 257     private:
 258         static const intptr_t HostCallFrameFlag = 1;
 259         static const int s_thisArgumentOffset = -1 - RegisterFile::CallFrameHeaderSize;
 260         static const int s_firstArgumentOffset = s_thisArgumentOffset - 1;
 261
 262 #ifndef NDEBUG
 263         RegisterFile* registerFile();
 264 #endif
 265 #if ENABLE(DFG_JIT)
 266         bool isInlineCallFrameSlow();
 267 #endif
 268         ExecState();
 269         ~ExecState();
 270     };
 271
 272 } // namespace JSC
 273
 274 #endif // CallFrame_h