JavaScriptCore/bytecompiler/BytecodeGenerator.cpp

   1 /*
   2  * Copyright (C) 2008, 2009 Apple Inc. All rights reserved.
   3  * Copyright (C) 2008 Cameron Zwarich <cwzwarich@uwaterloo.ca>
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  *
   9  * 1.  Redistributions of source code must retain the above copyright
  10  *     notice, this list of conditions and the following disclaimer.
  11  * 2.  Redistributions in binary form must reproduce the above copyright
  12  *     notice, this list of conditions and the following disclaimer in the
  13  *     documentation and/or other materials provided with the distribution.
  14  * 3.  Neither the name of Apple Computer, Inc. ("Apple") nor the names of
  15  *     its contributors may be used to endorse or promote products derived
  16  *     from this software without specific prior written permission.
  17  *
  18  * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
  19  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
  20  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  21  * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
  22  * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
  23  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  24  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
  25  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  26  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  27  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  28  */
  29
  30 #include "config.h"
  31 #include "BytecodeGenerator.h"
  32
  33 #include "BatchedTransitionOptimizer.h"
  34 #include "PrototypeFunction.h"
  35 #include "JSFunction.h"
  36 #include "Interpreter.h"
  37 #include "UString.h"
  38
  39 using namespace std;
  40
  41 namespace JSC {
  42
  43 /*
  44     The layout of a register frame looks like this:
  45
  46     For
  47
  48     function f(x, y) {
  49         var v1;
  50         function g() { }
  51         var v2;
  52         return (x) * (y);
  53     }
  54
  55     assuming (x) and (y) generated temporaries t1 and t2, you would have
  56
  57     ------------------------------------
  58     |  x |  y |  g | v2 | v1 | t1 | t2 | <-- value held
  59     ------------------------------------
  60     | -5 | -4 | -3 | -2 | -1 | +0 | +1 | <-- register index
  61     ------------------------------------
  62     | params->|<-locals      | temps->
  63
  64     Because temporary registers are allocated in a stack-like fashion, we
  65     can reclaim them with a simple popping algorithm. The same goes for labels.
  66     (We never reclaim parameter or local registers, because parameters and
  67     locals are DontDelete.)
  68
  69     The register layout before a function call looks like this:
  70
  71     For
  72
  73     function f(x, y)
  74     {
  75     }
  76
  77     f(1);
  78
  79     >                        <------------------------------
  80     <                        >  reserved: call frame  |  1 | <-- value held
  81     >         >snip<         <------------------------------
  82     <                        > +0 | +1 | +2 | +3 | +4 | +5 | <-- register index
  83     >                        <------------------------------
  84     | params->|<-locals      | temps->
  85
  86     The call instruction fills in the "call frame" registers. It also pads
  87     missing arguments at the end of the call:
  88
  89     >                        <-----------------------------------
  90     <                        >  reserved: call frame  |  1 |  ? | <-- value held ("?" stands for "undefined")
  91     >         >snip<         <-----------------------------------
  92     <                        > +0 | +1 | +2 | +3 | +4 | +5 | +6 | <-- register index
  93     >                        <-----------------------------------
  94     | params->|<-locals      | temps->
  95
  96     After filling in missing arguments, the call instruction sets up the new
  97     stack frame to overlap the end of the old stack frame:
  98
  99                              |---------------------------------->                        <
 100                              |  reserved: call frame  |  1 |  ? <                        > <-- value held ("?" stands for "undefined")
 101                              |---------------------------------->         >snip<         <
 102                              | -7 | -6 | -5 | -4 | -3 | -2 | -1 <                        > <-- register index
 103                              |---------------------------------->                        <
 104                              |                        | params->|<-locals       | temps->
 105
 106     That way, arguments are "copied" into the callee's stack frame for free.
 107
 108     If the caller supplies too many arguments, this trick doesn't work. The
 109     extra arguments protrude into space reserved for locals and temporaries.
 110     In that case, the call instruction makes a real copy of the call frame header,
 111     along with just the arguments expected by the callee, leaving the original
 112     call frame header and arguments behind. (The call instruction can't just discard
 113     extra arguments, because the "arguments" object may access them later.)
 114     This copying strategy ensures that all named values will be at the indices
 115     expected by the callee.
 116 */
 117
 118 #ifndef NDEBUG
 119 static bool s_dumpsGeneratedCode = false;
 120 #endif
 121
 122 void BytecodeGenerator::setDumpsGeneratedCode(bool dumpsGeneratedCode)
 123 {
 124 #ifndef NDEBUG
 125     s_dumpsGeneratedCode = dumpsGeneratedCode;
 126 #else
 127     UNUSED_PARAM(dumpsGeneratedCode);
 128 #endif
 129 }
 130
 131 bool BytecodeGenerator::dumpsGeneratedCode()
 132 {
 133 #ifndef NDEBUG
 134     return s_dumpsGeneratedCode;
 135 #else
 136     return false;
 137 #endif
 138 }
 139
 140 void BytecodeGenerator::generate()
 141 {
 142     m_codeBlock->setThisRegister(m_thisRegister.index());
 143
 144     m_scopeNode->emitBytecode(*this);
 145
 146 #ifndef NDEBUG
 147     m_codeBlock->setInstructionCount(m_codeBlock->instructions().size());
 148
 149     if (s_dumpsGeneratedCode)
 150         m_codeBlock->dump(m_scopeChain->globalObject()->globalExec());
 151 #endif
 152
 153     if ((m_codeType == FunctionCode && !m_codeBlock->needsFullScopeChain() && !m_codeBlock->usesArguments()) || m_codeType == EvalCode)
 154         symbolTable().clear();
 155
 156     m_codeBlock->setIsNumericCompareFunction(instructions() == m_globalData->numericCompareFunction(m_scopeChain->globalObject()->globalExec()));
 157
 158 #if !ENABLE(OPCODE_SAMPLING)
 159     if (!m_regeneratingForExceptionInfo && (m_codeType == FunctionCode || m_codeType == EvalCode))
 160         m_codeBlock->clearExceptionInfo();
 161 #endif
 162
 163     m_codeBlock->shrinkToFit();
 164 }
 165
 166 bool BytecodeGenerator::addVar(const Identifier& ident, bool isConstant, RegisterID*& r0)
 167 {
 168     int index = m_calleeRegisters.size();
 169     SymbolTableEntry newEntry(index, isConstant ? ReadOnly : 0);
 170     pair<SymbolTable::iterator, bool> result = symbolTable().add(ident.ustring().rep(), newEntry);
 171
 172     if (!result.second) {
 173         r0 = &registerFor(result.first->second.getIndex());
 174         return false;
 175     }
 176
 177     ++m_codeBlock->m_numVars;
 178     r0 = newRegister();
 179     return true;
 180 }
 181
 182 bool BytecodeGenerator::addGlobalVar(const Identifier& ident, bool isConstant, RegisterID*& r0)
 183 {
 184     int index = m_nextGlobalIndex;
 185     SymbolTableEntry newEntry(index, isConstant ? ReadOnly : 0);
 186     pair<SymbolTable::iterator, bool> result = symbolTable().add(ident.ustring().rep(), newEntry);
 187
 188     if (!result.second)
 189         index = result.first->second.getIndex();
 190     else {
 191         --m_nextGlobalIndex;
 192         m_globals.append(index + m_globalVarStorageOffset);
 193     }
 194
 195     r0 = &registerFor(index);
 196     return result.second;
 197 }
 198
 199 void BytecodeGenerator::preserveLastVar()
 200 {
 201     if ((m_firstConstantIndex = m_calleeRegisters.size()) != 0)
 202         m_lastVar = &m_calleeRegisters.last();
 203 }
 204
 205 BytecodeGenerator::BytecodeGenerator(ProgramNode* programNode, const Debugger* debugger, const ScopeChain& scopeChain, SymbolTable* symbolTable, ProgramCodeBlock* codeBlock)
 206     : m_shouldEmitDebugHooks(!!debugger)
 207     , m_shouldEmitProfileHooks(scopeChain.globalObject()->supportsProfiling())
 208     , m_scopeChain(&scopeChain)
 209     , m_symbolTable(symbolTable)
 210     , m_scopeNode(programNode)
 211     , m_codeBlock(codeBlock)
 212     , m_thisRegister(RegisterFile::ProgramCodeThisRegister)
 213     , m_finallyDepth(0)
 214     , m_dynamicScopeDepth(0)
 215     , m_baseScopeDepth(0)
 216     , m_codeType(GlobalCode)
 217     , m_nextGlobalIndex(-1)
 218     , m_nextConstantOffset(0)
 219     , m_globalConstantIndex(0)
 220     , m_globalData(&scopeChain.globalObject()->globalExec()->globalData())
 221     , m_lastOpcodeID(op_end)
 222     , m_emitNodeDepth(0)
 223     , m_regeneratingForExceptionInfo(false)
 224     , m_codeBlockBeingRegeneratedFrom(0)
 225 {
 226     if (m_shouldEmitDebugHooks)
 227         m_codeBlock->setNeedsFullScopeChain(true);
 228
 229     emitOpcode(op_enter);
 230     codeBlock->setGlobalData(m_globalData);
 231
 232     // FIXME: Move code that modifies the global object to Interpreter::execute.
 233
 234     m_codeBlock->m_numParameters = 1; // Allocate space for "this"
 235
 236     JSGlobalObject* globalObject = scopeChain.globalObject();
 237     ExecState* exec = globalObject->globalExec();
 238     RegisterFile* registerFile = &exec->globalData().interpreter->registerFile();
 239
 240     // Shift register indexes in generated code to elide registers allocated by intermediate stack frames.
 241     m_globalVarStorageOffset = -RegisterFile::CallFrameHeaderSize - m_codeBlock->m_numParameters - registerFile->size();
 242
 243     // Add previously defined symbols to bookkeeping.
 244     m_globals.grow(symbolTable->size());
 245     SymbolTable::iterator end = symbolTable->end();
 246     for (SymbolTable::iterator it = symbolTable->begin(); it != end; ++it)
 247         registerFor(it->second.getIndex()).setIndex(it->second.getIndex() + m_globalVarStorageOffset);
 248
 249     BatchedTransitionOptimizer optimizer(globalObject);
 250
 251     const VarStack& varStack = programNode->varStack();
 252     const FunctionStack& functionStack = programNode->functionStack();
 253     bool canOptimizeNewGlobals = symbolTable->size() + functionStack.size() + varStack.size() < registerFile->maxGlobals();
 254     if (canOptimizeNewGlobals) {
 255         // Shift new symbols so they get stored prior to existing symbols.
 256         m_nextGlobalIndex -= symbolTable->size();
 257
 258         for (size_t i = 0; i < functionStack.size(); ++i) {
 259             FunctionBodyNode* function = functionStack[i];
 260             globalObject->removeDirect(function->ident()); // Make sure our new function is not shadowed by an old property.
 261             emitNewFunction(addGlobalVar(function->ident(), false), function);
 262         }
 263
 264         Vector<RegisterID*, 32> newVars;
 265         for (size_t i = 0; i < varStack.size(); ++i)
 266             if (!globalObject->hasProperty(exec, *varStack[i].first))
 267                 newVars.append(addGlobalVar(*varStack[i].first, varStack[i].second & DeclarationStacks::IsConstant));
 268
 269         preserveLastVar();
 270
 271         for (size_t i = 0; i < newVars.size(); ++i)
 272             emitLoad(newVars[i], jsUndefined());
 273     } else {
 274         for (size_t i = 0; i < functionStack.size(); ++i) {
 275             FunctionBodyNode* function = functionStack[i];
 276             globalObject->putWithAttributes(exec, function->ident(), new (exec) JSFunction(exec, makeFunction(exec, function), scopeChain.node()), DontDelete);
 277         }
 278         for (size_t i = 0; i < varStack.size(); ++i) {
 279             if (globalObject->hasProperty(exec, *varStack[i].first))
 280                 continue;
 281             int attributes = DontDelete;
 282             if (varStack[i].second & DeclarationStacks::IsConstant)
 283                 attributes |= ReadOnly;
 284             globalObject->putWithAttributes(exec, *varStack[i].first, jsUndefined(), attributes);
 285         }
 286
 287         preserveLastVar();
 288     }
 289 }
 290
 291 BytecodeGenerator::BytecodeGenerator(FunctionBodyNode* functionBody, const Debugger* debugger, const ScopeChain& scopeChain, SymbolTable* symbolTable, CodeBlock* codeBlock)
 292     : m_shouldEmitDebugHooks(!!debugger)
 293     , m_shouldEmitProfileHooks(scopeChain.globalObject()->supportsProfiling())
 294     , m_scopeChain(&scopeChain)
 295     , m_symbolTable(symbolTable)
 296     , m_scopeNode(functionBody)
 297     , m_codeBlock(codeBlock)
 298     , m_finallyDepth(0)
 299     , m_dynamicScopeDepth(0)
 300     , m_baseScopeDepth(0)
 301     , m_codeType(FunctionCode)
 302     , m_nextConstantOffset(0)
 303     , m_globalConstantIndex(0)
 304     , m_globalData(&scopeChain.globalObject()->globalExec()->globalData())
 305     , m_lastOpcodeID(op_end)
 306     , m_emitNodeDepth(0)
 307     , m_regeneratingForExceptionInfo(false)
 308     , m_codeBlockBeingRegeneratedFrom(0)
 309 {
 310     if (m_shouldEmitDebugHooks)
 311         m_codeBlock->setNeedsFullScopeChain(true);
 312
 313     codeBlock->setGlobalData(m_globalData);
 314
 315     bool usesArguments = functionBody->usesArguments();
 316     codeBlock->setUsesArguments(usesArguments);
 317     if (usesArguments) {
 318         m_argumentsRegister.setIndex(RegisterFile::OptionalCalleeArguments);
 319         addVar(propertyNames().arguments, false);
 320     }
 321
 322     if (m_codeBlock->needsFullScopeChain()) {
 323         ++m_codeBlock->m_numVars;
 324         m_activationRegisterIndex = newRegister()->index();
 325         emitOpcode(op_enter_with_activation);
 326         instructions().append(m_activationRegisterIndex);
 327     } else
 328         emitOpcode(op_enter);
 329
 330     if (usesArguments) {
 331         emitOpcode(op_init_arguments);
 332
 333         // The debugger currently retrieves the arguments object from an activation rather than pulling
 334         // it from a call frame.  In the long-term it should stop doing that (<rdar://problem/6911886>),
 335         // but for now we force eager creation of the arguments object when debugging.
 336         if (m_shouldEmitDebugHooks)
 337             emitOpcode(op_create_arguments);
 338     }
 339
 340     const DeclarationStacks::FunctionStack& functionStack = functionBody->functionStack();
 341     for (size_t i = 0; i < functionStack.size(); ++i) {
 342         FunctionBodyNode* function = functionStack[i];
 343         const Identifier& ident = function->ident();
 344         m_functions.add(ident.ustring().rep());
 345         emitNewFunction(addVar(ident, false), function);
 346     }
 347
 348     const DeclarationStacks::VarStack& varStack = functionBody->varStack();
 349     for (size_t i = 0; i < varStack.size(); ++i)
 350         addVar(*varStack[i].first, varStack[i].second & DeclarationStacks::IsConstant);
 351
 352     FunctionParameters& parameters = *functionBody->parameters();
 353     size_t parameterCount = parameters.size();
 354     m_nextParameterIndex = -RegisterFile::CallFrameHeaderSize - parameterCount - 1;
 355     m_parameters.grow(1 + parameterCount); // reserve space for "this"
 356
 357     // Add "this" as a parameter
 358     m_thisRegister.setIndex(m_nextParameterIndex);
 359     ++m_nextParameterIndex;
 360     ++m_codeBlock->m_numParameters;
 361
 362     if (functionBody->usesThis() || m_shouldEmitDebugHooks) {
 363         emitOpcode(op_convert_this);
 364         instructions().append(m_thisRegister.index());
 365     }
 366
 367     for (size_t i = 0; i < parameterCount; ++i)
 368         addParameter(parameters[i]);
 369
 370     preserveLastVar();
 371 }
 372
 373 BytecodeGenerator::BytecodeGenerator(EvalNode* evalNode, const Debugger* debugger, const ScopeChain& scopeChain, SymbolTable* symbolTable, EvalCodeBlock* codeBlock)
 374     : m_shouldEmitDebugHooks(!!debugger)
 375     , m_shouldEmitProfileHooks(scopeChain.globalObject()->supportsProfiling())
 376     , m_scopeChain(&scopeChain)
 377     , m_symbolTable(symbolTable)
 378     , m_scopeNode(evalNode)
 379     , m_codeBlock(codeBlock)
 380     , m_thisRegister(RegisterFile::ProgramCodeThisRegister)
 381     , m_finallyDepth(0)
 382     , m_dynamicScopeDepth(0)
 383     , m_baseScopeDepth(codeBlock->baseScopeDepth())
 384     , m_codeType(EvalCode)
 385     , m_nextConstantOffset(0)
 386     , m_globalConstantIndex(0)
 387     , m_globalData(&scopeChain.globalObject()->globalExec()->globalData())
 388     , m_lastOpcodeID(op_end)
 389     , m_emitNodeDepth(0)
 390     , m_regeneratingForExceptionInfo(false)
 391     , m_codeBlockBeingRegeneratedFrom(0)
 392 {
 393     if (m_shouldEmitDebugHooks || m_baseScopeDepth)
 394         m_codeBlock->setNeedsFullScopeChain(true);
 395
 396     emitOpcode(op_enter);
 397     codeBlock->setGlobalData(m_globalData);
 398     m_codeBlock->m_numParameters = 1; // Allocate space for "this"
 399
 400     const DeclarationStacks::FunctionStack& functionStack = evalNode->functionStack();
 401     for (size_t i = 0; i < functionStack.size(); ++i)
 402         m_codeBlock->addFunctionDecl(makeFunction(m_globalData, functionStack[i]));
 403
 404     const DeclarationStacks::VarStack& varStack = evalNode->varStack();
 405     unsigned numVariables = varStack.size();
 406     Vector<Identifier> variables;
 407     variables.reserveCapacity(numVariables);
 408     for (size_t i = 0; i < numVariables; ++i)
 409         variables.append(*varStack[i].first);
 410     codeBlock->adoptVariables(variables);
 411
 412     preserveLastVar();
 413 }
 414
 415 RegisterID* BytecodeGenerator::addParameter(const Identifier& ident)
 416 {
 417     // Parameters overwrite var declarations, but not function declarations.
 418     RegisterID* result = 0;
 419     UString::Rep* rep = ident.ustring().rep();
 420     if (!m_functions.contains(rep)) {
 421         symbolTable().set(rep, m_nextParameterIndex);
 422         RegisterID& parameter = registerFor(m_nextParameterIndex);
 423         parameter.setIndex(m_nextParameterIndex);
 424         result = &parameter;
 425     }
 426
 427     // To maintain the calling convention, we have to allocate unique space for
 428     // each parameter, even if the parameter doesn't make it into the symbol table.
 429     ++m_nextParameterIndex;
 430     ++m_codeBlock->m_numParameters;
 431     return result;
 432 }
 433
 434 RegisterID* BytecodeGenerator::registerFor(const Identifier& ident)
 435 {
 436     if (ident == propertyNames().thisIdentifier)
 437         return &m_thisRegister;
 438
 439     if (!shouldOptimizeLocals())
 440         return 0;
 441
 442     SymbolTableEntry entry = symbolTable().get(ident.ustring().rep());
 443     if (entry.isNull())
 444         return 0;
 445
 446     if (ident == propertyNames().arguments)
 447         createArgumentsIfNecessary();
 448
 449     return &registerFor(entry.getIndex());
 450 }
 451
 452 bool BytecodeGenerator::willResolveToArguments(const Identifier& ident)
 453 {
 454     if (ident != propertyNames().arguments)
 455         return false;
 456
 457     if (!shouldOptimizeLocals())
 458         return false;
 459
 460     SymbolTableEntry entry = symbolTable().get(ident.ustring().rep());
 461     if (entry.isNull())
 462         return false;
 463
 464     if (m_codeBlock->usesArguments() && m_codeType == FunctionCode)
 465         return true;
 466
 467     return false;
 468 }
 469
 470 RegisterID* BytecodeGenerator::uncheckedRegisterForArguments()
 471 {
 472     ASSERT(willResolveToArguments(propertyNames().arguments));
 473
 474     SymbolTableEntry entry = symbolTable().get(propertyNames().arguments.ustring().rep());
 475     ASSERT(!entry.isNull());
 476     return &registerFor(entry.getIndex());
 477 }
 478
 479 RegisterID* BytecodeGenerator::constRegisterFor(const Identifier& ident)
 480 {
 481     if (m_codeType == EvalCode)
 482         return 0;
 483
 484     SymbolTableEntry entry = symbolTable().get(ident.ustring().rep());
 485     if (entry.isNull())
 486         return 0;
 487
 488     return &registerFor(entry.getIndex());
 489 }
 490
 491 bool BytecodeGenerator::isLocal(const Identifier& ident)
 492 {
 493     if (ident == propertyNames().thisIdentifier)
 494         return true;
 495
 496     return shouldOptimizeLocals() && symbolTable().contains(ident.ustring().rep());
 497 }
 498
 499 bool BytecodeGenerator::isLocalConstant(const Identifier& ident)
 500 {
 501     return symbolTable().get(ident.ustring().rep()).isReadOnly();
 502 }
 503
 504 RegisterID* BytecodeGenerator::newRegister()
 505 {
 506     m_calleeRegisters.append(m_calleeRegisters.size());
 507     m_codeBlock->m_numCalleeRegisters = max<int>(m_codeBlock->m_numCalleeRegisters, m_calleeRegisters.size());
 508     return &m_calleeRegisters.last();
 509 }
 510
 511 RegisterID* BytecodeGenerator::newTemporary()
 512 {
 513     // Reclaim free register IDs.
 514     while (m_calleeRegisters.size() && !m_calleeRegisters.last().refCount())
 515         m_calleeRegisters.removeLast();
 516
 517     RegisterID* result = newRegister();
 518     result->setTemporary();
 519     return result;
 520 }
 521
 522 RegisterID* BytecodeGenerator::highestUsedRegister()
 523 {
 524     size_t count = m_codeBlock->m_numCalleeRegisters;
 525     while (m_calleeRegisters.size() < count)
 526         newRegister();
 527     return &m_calleeRegisters.last();
 528 }
 529
 530 PassRefPtr<LabelScope> BytecodeGenerator::newLabelScope(LabelScope::Type type, const Identifier* name)
 531 {
 532     // Reclaim free label scopes.
 533     while (m_labelScopes.size() && !m_labelScopes.last().refCount())
 534         m_labelScopes.removeLast();
 535
 536     // Allocate new label scope.
 537     LabelScope scope(type, name, scopeDepth(), newLabel(), type == LabelScope::Loop ? newLabel() : PassRefPtr<Label>()); // Only loops have continue targets.
 538     m_labelScopes.append(scope);
 539     return &m_labelScopes.last();
 540 }
 541
 542 PassRefPtr<Label> BytecodeGenerator::newLabel()
 543 {
 544     // Reclaim free label IDs.
 545     while (m_labels.size() && !m_labels.last().refCount())
 546         m_labels.removeLast();
 547
 548     // Allocate new label ID.
 549     m_labels.append(m_codeBlock);
 550     return &m_labels.last();
 551 }
 552
 553 PassRefPtr<Label> BytecodeGenerator::emitLabel(Label* l0)
 554 {
 555     unsigned newLabelIndex = instructions().size();
 556     l0->setLocation(newLabelIndex);
 557
 558     if (m_codeBlock->numberOfJumpTargets()) {
 559         unsigned lastLabelIndex = m_codeBlock->lastJumpTarget();
 560         ASSERT(lastLabelIndex <= newLabelIndex);
 561         if (newLabelIndex == lastLabelIndex) {
 562             // Peephole optimizations have already been disabled by emitting the last label
 563             return l0;
 564         }
 565     }
 566
 567     m_codeBlock->addJumpTarget(newLabelIndex);
 568
 569     // This disables peephole optimizations when an instruction is a jump target
 570     m_lastOpcodeID = op_end;
 571     return l0;
 572 }
 573
 574 void BytecodeGenerator::emitOpcode(OpcodeID opcodeID)
 575 {
 576     instructions().append(globalData()->interpreter->getOpcode(opcodeID));
 577     m_lastOpcodeID = opcodeID;
 578 }
 579
 580 void BytecodeGenerator::retrieveLastBinaryOp(int& dstIndex, int& src1Index, int& src2Index)
 581 {
 582     ASSERT(instructions().size() >= 4);
 583     size_t size = instructions().size();
 584     dstIndex = instructions().at(size - 3).u.operand;
 585     src1Index = instructions().at(size - 2).u.operand;
 586     src2Index = instructions().at(size - 1).u.operand;
 587 }
 588
 589 void BytecodeGenerator::retrieveLastUnaryOp(int& dstIndex, int& srcIndex)
 590 {
 591     ASSERT(instructions().size() >= 3);
 592     size_t size = instructions().size();
 593     dstIndex = instructions().at(size - 2).u.operand;
 594     srcIndex = instructions().at(size - 1).u.operand;
 595 }
 596
 597 void ALWAYS_INLINE BytecodeGenerator::rewindBinaryOp()
 598 {
 599     ASSERT(instructions().size() >= 4);
 600     instructions().shrink(instructions().size() - 4);
 601 }
 602
 603 void ALWAYS_INLINE BytecodeGenerator::rewindUnaryOp()
 604 {
 605     ASSERT(instructions().size() >= 3);
 606     instructions().shrink(instructions().size() - 3);
 607 }
 608
 609 PassRefPtr<Label> BytecodeGenerator::emitJump(Label* target)
 610 {
 611     size_t begin = instructions().size();
 612     emitOpcode(target->isForward() ? op_jmp : op_loop);
 613     instructions().append(target->bind(begin, instructions().size()));
 614     return target;
 615 }
 616
 617 PassRefPtr<Label> BytecodeGenerator::emitJumpIfTrue(RegisterID* cond, Label* target)
 618 {
 619     if (m_lastOpcodeID == op_less) {
 620         int dstIndex;
 621         int src1Index;
 622         int src2Index;
 623
 624         retrieveLastBinaryOp(dstIndex, src1Index, src2Index);
 625
 626         if (cond->index() == dstIndex && cond->isTemporary() && !cond->refCount()) {
 627             rewindBinaryOp();
 628
 629             size_t begin = instructions().size();
 630             emitOpcode(target->isForward() ? op_jless : op_loop_if_less);
 631             instructions().append(src1Index);
 632             instructions().append(src2Index);
 633             instructions().append(target->bind(begin, instructions().size()));
 634             return target;
 635         }
 636     } else if (m_lastOpcodeID == op_lesseq && !target->isForward()) {
 637         int dstIndex;
 638         int src1Index;
 639         int src2Index;
 640
 641         retrieveLastBinaryOp(dstIndex, src1Index, src2Index);
 642
 643         if (cond->index() == dstIndex && cond->isTemporary() && !cond->refCount()) {
 644             rewindBinaryOp();
 645
 646             size_t begin = instructions().size();
 647             emitOpcode(op_loop_if_lesseq);
 648             instructions().append(src1Index);
 649             instructions().append(src2Index);
 650             instructions().append(target->bind(begin, instructions().size()));
 651             return target;
 652         }
 653     } else if (m_lastOpcodeID == op_eq_null && target->isForward()) {
 654         int dstIndex;
 655         int srcIndex;
 656
 657         retrieveLastUnaryOp(dstIndex, srcIndex);
 658
 659         if (cond->index() == dstIndex && cond->isTemporary() && !cond->refCount()) {
 660             rewindUnaryOp();
 661
 662             size_t begin = instructions().size();
 663             emitOpcode(op_jeq_null);
 664             instructions().append(srcIndex);
 665             instructions().append(target->bind(begin, instructions().size()));
 666             return target;
 667         }
 668     } else if (m_lastOpcodeID == op_neq_null && target->isForward()) {
 669         int dstIndex;
 670         int srcIndex;
 671
 672         retrieveLastUnaryOp(dstIndex, srcIndex);
 673
 674         if (cond->index() == dstIndex && cond->isTemporary() && !cond->refCount()) {
 675             rewindUnaryOp();
 676
 677             size_t begin = instructions().size();
 678             emitOpcode(op_jneq_null);
 679             instructions().append(srcIndex);
 680             instructions().append(target->bind(begin, instructions().size()));
 681             return target;
 682         }
 683     }
 684
 685     size_t begin = instructions().size();
 686
 687     emitOpcode(target->isForward() ? op_jtrue : op_loop_if_true);
 688     instructions().append(cond->index());
 689     instructions().append(target->bind(begin, instructions().size()));
 690     return target;
 691 }
 692
 693 PassRefPtr<Label> BytecodeGenerator::emitJumpIfFalse(RegisterID* cond, Label* target)
 694 {
 695     if (m_lastOpcodeID == op_less && target->isForward()) {
 696         int dstIndex;
 697         int src1Index;
 698         int src2Index;
 699
 700         retrieveLastBinaryOp(dstIndex, src1Index, src2Index);
 701
 702         if (cond->index() == dstIndex && cond->isTemporary() && !cond->refCount()) {
 703             rewindBinaryOp();
 704
 705             size_t begin = instructions().size();
 706             emitOpcode(op_jnless);
 707             instructions().append(src1Index);
 708             instructions().append(src2Index);
 709             instructions().append(target->bind(begin, instructions().size()));
 710             return target;
 711         }
 712     } else if (m_lastOpcodeID == op_lesseq && target->isForward()) {
 713         int dstIndex;
 714         int src1Index;
 715         int src2Index;
 716
 717         retrieveLastBinaryOp(dstIndex, src1Index, src2Index);
 718
 719         if (cond->index() == dstIndex && cond->isTemporary() && !cond->refCount()) {
 720             rewindBinaryOp();
 721
 722             size_t begin = instructions().size();
 723             emitOpcode(op_jnlesseq);
 724             instructions().append(src1Index);
 725             instructions().append(src2Index);
 726             instructions().append(target->bind(begin, instructions().size()));
 727             return target;
 728         }
 729     } else if (m_lastOpcodeID == op_not) {
 730         int dstIndex;
 731         int srcIndex;
 732
 733         retrieveLastUnaryOp(dstIndex, srcIndex);
 734
 735         if (cond->index() == dstIndex && cond->isTemporary() && !cond->refCount()) {
 736             rewindUnaryOp();
 737
 738             size_t begin = instructions().size();
 739             emitOpcode(target->isForward() ? op_jtrue : op_loop_if_true);
 740             instructions().append(srcIndex);
 741             instructions().append(target->bind(begin, instructions().size()));
 742             return target;
 743         }
 744     } else if (m_lastOpcodeID == op_eq_null && target->isForward()) {
 745         int dstIndex;
 746         int srcIndex;
 747
 748         retrieveLastUnaryOp(dstIndex, srcIndex);
 749
 750         if (cond->index() == dstIndex && cond->isTemporary() && !cond->refCount()) {
 751             rewindUnaryOp();
 752
 753             size_t begin = instructions().size();
 754             emitOpcode(op_jneq_null);
 755             instructions().append(srcIndex);
 756             instructions().append(target->bind(begin, instructions().size()));
 757             return target;
 758         }
 759     } else if (m_lastOpcodeID == op_neq_null && target->isForward()) {
 760         int dstIndex;
 761         int srcIndex;
 762
 763         retrieveLastUnaryOp(dstIndex, srcIndex);
 764
 765         if (cond->index() == dstIndex && cond->isTemporary() && !cond->refCount()) {
 766             rewindUnaryOp();
 767
 768             size_t begin = instructions().size();
 769             emitOpcode(op_jeq_null);
 770             instructions().append(srcIndex);
 771             instructions().append(target->bind(begin, instructions().size()));
 772             return target;
 773         }
 774     }
 775
 776     size_t begin = instructions().size();
 777     emitOpcode(target->isForward() ? op_jfalse : op_loop_if_false);
 778     instructions().append(cond->index());
 779     instructions().append(target->bind(begin, instructions().size()));
 780     return target;
 781 }
 782
 783 PassRefPtr<Label> BytecodeGenerator::emitJumpIfNotFunctionCall(RegisterID* cond, Label* target)
 784 {
 785     size_t begin = instructions().size();
 786
 787     emitOpcode(op_jneq_ptr);
 788     instructions().append(cond->index());
 789     instructions().append(m_scopeChain->globalObject()->d()->callFunction);
 790     instructions().append(target->bind(begin, instructions().size()));
 791     return target;
 792 }
 793
 794 PassRefPtr<Label> BytecodeGenerator::emitJumpIfNotFunctionApply(RegisterID* cond, Label* target)
 795 {
 796     size_t begin = instructions().size();
 797
 798     emitOpcode(op_jneq_ptr);
 799     instructions().append(cond->index());
 800     instructions().append(m_scopeChain->globalObject()->d()->applyFunction);
 801     instructions().append(target->bind(begin, instructions().size()));
 802     return target;
 803 }
 804
 805 unsigned BytecodeGenerator::addConstant(const Identifier& ident)
 806 {
 807     UString::Rep* rep = ident.ustring().rep();
 808     pair<IdentifierMap::iterator, bool> result = m_identifierMap.add(rep, m_codeBlock->numberOfIdentifiers());
 809     if (result.second) // new entry
 810         m_codeBlock->addIdentifier(Identifier(m_globalData, rep));
 811
 812     return result.first->second;
 813 }
 814
 815 RegisterID* BytecodeGenerator::addConstantValue(JSValue v)
 816 {
 817     int index = m_nextConstantOffset;
 818
 819     pair<JSValueMap::iterator, bool> result = m_jsValueMap.add(JSValue::encode(v), m_nextConstantOffset);
 820     if (result.second) {
 821         m_constantPoolRegisters.append(FirstConstantRegisterIndex + m_nextConstantOffset);
 822         ++m_nextConstantOffset;
 823         m_codeBlock->addConstantRegister(JSValue(v));
 824     } else
 825         index = result.first->second;
 826
 827     return &m_constantPoolRegisters[index];
 828 }
 829
 830 unsigned BytecodeGenerator::addRegExp(RegExp* r)
 831 {
 832     return m_codeBlock->addRegExp(r);
 833 }
 834
 835 RegisterID* BytecodeGenerator::emitMove(RegisterID* dst, RegisterID* src)
 836 {
 837     emitOpcode(op_mov);
 838     instructions().append(dst->index());
 839     instructions().append(src->index());
 840     return dst;
 841 }
 842
 843 RegisterID* BytecodeGenerator::emitUnaryOp(OpcodeID opcodeID, RegisterID* dst, RegisterID* src)
 844 {
 845     emitOpcode(opcodeID);
 846     instructions().append(dst->index());
 847     instructions().append(src->index());
 848     return dst;
 849 }
 850
 851 RegisterID* BytecodeGenerator::emitPreInc(RegisterID* srcDst)
 852 {
 853     emitOpcode(op_pre_inc);
 854     instructions().append(srcDst->index());
 855     return srcDst;
 856 }
 857
 858 RegisterID* BytecodeGenerator::emitPreDec(RegisterID* srcDst)
 859 {
 860     emitOpcode(op_pre_dec);
 861     instructions().append(srcDst->index());
 862     return srcDst;
 863 }
 864
 865 RegisterID* BytecodeGenerator::emitPostInc(RegisterID* dst, RegisterID* srcDst)
 866 {
 867     emitOpcode(op_post_inc);
 868     instructions().append(dst->index());
 869     instructions().append(srcDst->index());
 870     return dst;
 871 }
 872
 873 RegisterID* BytecodeGenerator::emitPostDec(RegisterID* dst, RegisterID* srcDst)
 874 {
 875     emitOpcode(op_post_dec);
 876     instructions().append(dst->index());
 877     instructions().append(srcDst->index());
 878     return dst;
 879 }
 880
 881 RegisterID* BytecodeGenerator::emitBinaryOp(OpcodeID opcodeID, RegisterID* dst, RegisterID* src1, RegisterID* src2, OperandTypes types)
 882 {
 883     emitOpcode(opcodeID);
 884     instructions().append(dst->index());
 885     instructions().append(src1->index());
 886     instructions().append(src2->index());
 887
 888     if (opcodeID == op_bitor || opcodeID == op_bitand || opcodeID == op_bitxor ||
 889         opcodeID == op_add || opcodeID == op_mul || opcodeID == op_sub || opcodeID == op_div)
 890         instructions().append(types.toInt());
 891
 892     return dst;
 893 }
 894
 895 RegisterID* BytecodeGenerator::emitEqualityOp(OpcodeID opcodeID, RegisterID* dst, RegisterID* src1, RegisterID* src2)
 896 {
 897     if (m_lastOpcodeID == op_typeof) {
 898         int dstIndex;
 899         int srcIndex;
 900
 901         retrieveLastUnaryOp(dstIndex, srcIndex);
 902
 903         if (src1->index() == dstIndex
 904             && src1->isTemporary()
 905             && m_codeBlock->isConstantRegisterIndex(src2->index())
 906             && m_codeBlock->constantRegister(src2->index()).jsValue().isString()) {
 907             const UString& value = asString(m_codeBlock->constantRegister(src2->index()).jsValue())->tryGetValue();
 908             if (value == "undefined") {
 909                 rewindUnaryOp();
 910                 emitOpcode(op_is_undefined);
 911                 instructions().append(dst->index());
 912                 instructions().append(srcIndex);
 913                 return dst;
 914             }
 915             if (value == "boolean") {
 916                 rewindUnaryOp();
 917                 emitOpcode(op_is_boolean);
 918                 instructions().append(dst->index());
 919                 instructions().append(srcIndex);
 920                 return dst;
 921             }
 922             if (value == "number") {
 923                 rewindUnaryOp();
 924                 emitOpcode(op_is_number);
 925                 instructions().append(dst->index());
 926                 instructions().append(srcIndex);
 927                 return dst;
 928             }
 929             if (value == "string") {
 930                 rewindUnaryOp();
 931                 emitOpcode(op_is_string);
 932                 instructions().append(dst->index());
 933                 instructions().append(srcIndex);
 934                 return dst;
 935             }
 936             if (value == "object") {
 937                 rewindUnaryOp();
 938                 emitOpcode(op_is_object);
 939                 instructions().append(dst->index());
 940                 instructions().append(srcIndex);
 941                 return dst;
 942             }
 943             if (value == "function") {
 944                 rewindUnaryOp();
 945                 emitOpcode(op_is_function);
 946                 instructions().append(dst->index());
 947                 instructions().append(srcIndex);
 948                 return dst;
 949             }
 950         }
 951     }
 952
 953     emitOpcode(opcodeID);
 954     instructions().append(dst->index());
 955     instructions().append(src1->index());
 956     instructions().append(src2->index());
 957     return dst;
 958 }
 959
 960 RegisterID* BytecodeGenerator::emitLoad(RegisterID* dst, bool b)
 961 {
 962     return emitLoad(dst, jsBoolean(b));
 963 }
 964
 965 RegisterID* BytecodeGenerator::emitLoad(RegisterID* dst, double number)
 966 {
 967     // FIXME: Our hash tables won't hold infinity, so we make a new JSNumberCell each time.
 968     // Later we can do the extra work to handle that like the other cases.
 969     if (number == HashTraits<double>::emptyValue() || HashTraits<double>::isDeletedValue(number))
 970         return emitLoad(dst, jsNumber(globalData(), number));
 971     JSValue& valueInMap = m_numberMap.add(number, JSValue()).first->second;
 972     if (!valueInMap)
 973         valueInMap = jsNumber(globalData(), number);
 974     return emitLoad(dst, valueInMap);
 975 }
 976
 977 RegisterID* BytecodeGenerator::emitLoad(RegisterID* dst, const Identifier& identifier)
 978 {
 979     JSString*& stringInMap = m_stringMap.add(identifier.ustring().rep(), 0).first->second;
 980     if (!stringInMap)
 981         stringInMap = jsOwnedString(globalData(), identifier.ustring());
 982     return emitLoad(dst, JSValue(stringInMap));
 983 }
 984
 985 RegisterID* BytecodeGenerator::emitLoad(RegisterID* dst, JSValue v)
 986 {
 987     RegisterID* constantID = addConstantValue(v);
 988     if (dst)
 989         return emitMove(dst, constantID);
 990     return constantID;
 991 }
 992
 993 bool BytecodeGenerator::findScopedProperty(const Identifier& property, int& index, size_t& stackDepth, bool forWriting, JSObject*& globalObject)
 994 {
 995     // Cases where we cannot statically optimize the lookup.
 996     if (property == propertyNames().arguments || !canOptimizeNonLocals()) {
 997         stackDepth = 0;
 998         index = missingSymbolMarker();
 999
1000         if (shouldOptimizeLocals() && m_codeType == GlobalCode) {
1001             ScopeChainIterator iter = m_scopeChain->begin();
1002             globalObject = *iter;
1003             ASSERT((++iter) == m_scopeChain->end());
1004         }
1005         return false;
1006     }
1007
1008     size_t depth = 0;
1009
1010     ScopeChainIterator iter = m_scopeChain->begin();
1011     ScopeChainIterator end = m_scopeChain->end();
1012     for (; iter != end; ++iter, ++depth) {
1013         JSObject* currentScope = *iter;
1014         if (!currentScope->isVariableObject())
1015             break;
1016         JSVariableObject* currentVariableObject = static_cast<JSVariableObject*>(currentScope);
1017         SymbolTableEntry entry = currentVariableObject->symbolTable().get(property.ustring().rep());
1018
1019         // Found the property
1020         if (!entry.isNull()) {
1021             if (entry.isReadOnly() && forWriting) {
1022                 stackDepth = 0;
1023                 index = missingSymbolMarker();
1024                 if (++iter == end)
1025                     globalObject = currentVariableObject;
1026                 return false;
1027             }
1028             stackDepth = depth;
1029             index = entry.getIndex();
1030             if (++iter == end)
1031                 globalObject = currentVariableObject;
1032             return true;
1033         }
1034         if (currentVariableObject->isDynamicScope())
1035             break;
1036     }
1037
1038     // Can't locate the property but we're able to avoid a few lookups.
1039     stackDepth = depth;
1040     index = missingSymbolMarker();
1041     JSObject* scope = *iter;
1042     if (++iter == end)
1043         globalObject = scope;
1044     return true;
1045 }
1046
1047 RegisterID* BytecodeGenerator::emitInstanceOf(RegisterID* dst, RegisterID* value, RegisterID* base, RegisterID* basePrototype)
1048 {
1049     emitOpcode(op_instanceof);
1050     instructions().append(dst->index());
1051     instructions().append(value->index());
1052     instructions().append(base->index());
1053     instructions().append(basePrototype->index());
1054     return dst;
1055 }
1056
1057 RegisterID* BytecodeGenerator::emitResolve(RegisterID* dst, const Identifier& property)
1058 {
1059     size_t depth = 0;
1060     int index = 0;
1061     JSObject* globalObject = 0;
1062     if (!findScopedProperty(property, index, depth, false, globalObject) && !globalObject) {
1063         // We can't optimise at all :-(
1064         emitOpcode(op_resolve);
1065         instructions().append(dst->index());
1066         instructions().append(addConstant(property));
1067         return dst;
1068     }
1069
1070     if (globalObject) {
1071         bool forceGlobalResolve = false;
1072         if (m_regeneratingForExceptionInfo) {
1073 #if ENABLE(JIT)
1074             forceGlobalResolve = m_codeBlockBeingRegeneratedFrom->hasGlobalResolveInfoAtBytecodeOffset(instructions().size());
1075 #else
1076             forceGlobalResolve = m_codeBlockBeingRegeneratedFrom->hasGlobalResolveInstructionAtBytecodeOffset(instructions().size());
1077 #endif
1078         }
1079
1080         if (index != missingSymbolMarker() && !forceGlobalResolve) {
1081             // Directly index the property lookup across multiple scopes.
1082             return emitGetScopedVar(dst, depth, index, globalObject);
1083         }
1084
1085 #if ENABLE(JIT)
1086         m_codeBlock->addGlobalResolveInfo(instructions().size());
1087 #else
1088         m_codeBlock->addGlobalResolveInstruction(instructions().size());
1089 #endif
1090         emitOpcode(op_resolve_global);
1091         instructions().append(dst->index());
1092         instructions().append(globalObject);
1093         instructions().append(addConstant(property));
1094         instructions().append(0);
1095         instructions().append(0);
1096         return dst;
1097     }
1098
1099     if (index != missingSymbolMarker()) {
1100         // Directly index the property lookup across multiple scopes.
1101         return emitGetScopedVar(dst, depth, index, globalObject);
1102     }
1103
1104     // In this case we are at least able to drop a few scope chains from the
1105     // lookup chain, although we still need to hash from then on.
1106     emitOpcode(op_resolve_skip);
1107     instructions().append(dst->index());
1108     instructions().append(addConstant(property));
1109     instructions().append(depth);
1110     return dst;
1111 }
1112
1113 RegisterID* BytecodeGenerator::emitGetScopedVar(RegisterID* dst, size_t depth, int index, JSValue globalObject)
1114 {
1115     if (globalObject) {
1116         emitOpcode(op_get_global_var);
1117         instructions().append(dst->index());
1118         instructions().append(asCell(globalObject));
1119         instructions().append(index);
1120         return dst;
1121     }
1122
1123     emitOpcode(op_get_scoped_var);
1124     instructions().append(dst->index());
1125     instructions().append(index);
1126     instructions().append(depth);
1127     return dst;
1128 }
1129
1130 RegisterID* BytecodeGenerator::emitPutScopedVar(size_t depth, int index, RegisterID* value, JSValue globalObject)
1131 {
1132     if (globalObject) {
1133         emitOpcode(op_put_global_var);
1134         instructions().append(asCell(globalObject));
1135         instructions().append(index);
1136         instructions().append(value->index());
1137         return value;
1138     }
1139     emitOpcode(op_put_scoped_var);
1140     instructions().append(index);
1141     instructions().append(depth);
1142     instructions().append(value->index());
1143     return value;
1144 }
1145
1146 RegisterID* BytecodeGenerator::emitResolveBase(RegisterID* dst, const Identifier& property)
1147 {
1148     size_t depth = 0;
1149     int index = 0;
1150     JSObject* globalObject = 0;
1151     findScopedProperty(property, index, depth, false, globalObject);
1152     if (!globalObject) {
1153         // We can't optimise at all :-(
1154         emitOpcode(op_resolve_base);
1155         instructions().append(dst->index());
1156         instructions().append(addConstant(property));
1157         return dst;
1158     }
1159
1160     // Global object is the base
1161     return emitLoad(dst, JSValue(globalObject));
1162 }
1163
1164 RegisterID* BytecodeGenerator::emitResolveWithBase(RegisterID* baseDst, RegisterID* propDst, const Identifier& property)
1165 {
1166     size_t depth = 0;
1167     int index = 0;
1168     JSObject* globalObject = 0;
1169     if (!findScopedProperty(property, index, depth, false, globalObject) || !globalObject) {
1170         // We can't optimise at all :-(
1171         emitOpcode(op_resolve_with_base);
1172         instructions().append(baseDst->index());
1173         instructions().append(propDst->index());
1174         instructions().append(addConstant(property));
1175         return baseDst;
1176     }
1177
1178     bool forceGlobalResolve = false;
1179     if (m_regeneratingForExceptionInfo) {
1180 #if ENABLE(JIT)
1181         forceGlobalResolve = m_codeBlockBeingRegeneratedFrom->hasGlobalResolveInfoAtBytecodeOffset(instructions().size());
1182 #else
1183         forceGlobalResolve = m_codeBlockBeingRegeneratedFrom->hasGlobalResolveInstructionAtBytecodeOffset(instructions().size());
1184 #endif
1185     }
1186
1187     // Global object is the base
1188     emitLoad(baseDst, JSValue(globalObject));
1189
1190     if (index != missingSymbolMarker() && !forceGlobalResolve) {
1191         // Directly index the property lookup across multiple scopes.
1192         emitGetScopedVar(propDst, depth, index, globalObject);
1193         return baseDst;
1194     }
1195
1196 #if ENABLE(JIT)
1197     m_codeBlock->addGlobalResolveInfo(instructions().size());
1198 #else
1199     m_codeBlock->addGlobalResolveInstruction(instructions().size());
1200 #endif
1201     emitOpcode(op_resolve_global);
1202     instructions().append(propDst->index());
1203     instructions().append(globalObject);
1204     instructions().append(addConstant(property));
1205     instructions().append(0);
1206     instructions().append(0);
1207     return baseDst;
1208 }
1209
1210 void BytecodeGenerator::emitMethodCheck()
1211 {
1212     emitOpcode(op_method_check);
1213 }
1214
1215 RegisterID* BytecodeGenerator::emitGetById(RegisterID* dst, RegisterID* base, const Identifier& property)
1216 {
1217 #if ENABLE(JIT)
1218     m_codeBlock->addStructureStubInfo(StructureStubInfo(access_get_by_id));
1219 #else
1220     m_codeBlock->addPropertyAccessInstruction(instructions().size());
1221 #endif
1222
1223     emitOpcode(op_get_by_id);
1224     instructions().append(dst->index());
1225     instructions().append(base->index());
1226     instructions().append(addConstant(property));
1227     instructions().append(0);
1228     instructions().append(0);
1229     instructions().append(0);
1230     instructions().append(0);
1231     return dst;
1232 }
1233
1234 RegisterID* BytecodeGenerator::emitPutById(RegisterID* base, const Identifier& property, RegisterID* value)
1235 {
1236 #if ENABLE(JIT)
1237     m_codeBlock->addStructureStubInfo(StructureStubInfo(access_put_by_id));
1238 #else
1239     m_codeBlock->addPropertyAccessInstruction(instructions().size());
1240 #endif
1241
1242     emitOpcode(op_put_by_id);
1243     instructions().append(base->index());
1244     instructions().append(addConstant(property));
1245     instructions().append(value->index());
1246     instructions().append(0);
1247     instructions().append(0);
1248     instructions().append(0);
1249     instructions().append(0);
1250     return value;
1251 }
1252
1253 RegisterID* BytecodeGenerator::emitPutGetter(RegisterID* base, const Identifier& property, RegisterID* value)
1254 {
1255     emitOpcode(op_put_getter);
1256     instructions().append(base->index());
1257     instructions().append(addConstant(property));
1258     instructions().append(value->index());
1259     return value;
1260 }
1261
1262 RegisterID* BytecodeGenerator::emitPutSetter(RegisterID* base, const Identifier& property, RegisterID* value)
1263 {
1264     emitOpcode(op_put_setter);
1265     instructions().append(base->index());
1266     instructions().append(addConstant(property));
1267     instructions().append(value->index());
1268     return value;
1269 }
1270
1271 RegisterID* BytecodeGenerator::emitDeleteById(RegisterID* dst, RegisterID* base, const Identifier& property)
1272 {
1273     emitOpcode(op_del_by_id);
1274     instructions().append(dst->index());
1275     instructions().append(base->index());
1276     instructions().append(addConstant(property));
1277     return dst;
1278 }
1279
1280 RegisterID* BytecodeGenerator::emitGetByVal(RegisterID* dst, RegisterID* base, RegisterID* property)
1281 {
1282     for (size_t i = m_forInContextStack.size(); i > 0; i--) {
1283         ForInContext& context = m_forInContextStack[i - 1];
1284         if (context.propertyRegister == property) {
1285             emitOpcode(op_get_by_pname);
1286             instructions().append(dst->index());
1287             instructions().append(base->index());
1288             instructions().append(property->index());
1289             instructions().append(context.expectedSubscriptRegister->index());
1290             instructions().append(context.iterRegister->index());
1291             instructions().append(context.indexRegister->index());
1292             return dst;
1293         }
1294     }
1295     emitOpcode(op_get_by_val);
1296     instructions().append(dst->index());
1297     instructions().append(base->index());
1298     instructions().append(property->index());
1299     return dst;
1300 }
1301
1302 RegisterID* BytecodeGenerator::emitPutByVal(RegisterID* base, RegisterID* property, RegisterID* value)
1303 {
1304     emitOpcode(op_put_by_val);
1305     instructions().append(base->index());
1306     instructions().append(property->index());
1307     instructions().append(value->index());
1308     return value;
1309 }
1310
1311 RegisterID* BytecodeGenerator::emitDeleteByVal(RegisterID* dst, RegisterID* base, RegisterID* property)
1312 {
1313     emitOpcode(op_del_by_val);
1314     instructions().append(dst->index());
1315     instructions().append(base->index());
1316     instructions().append(property->index());
1317     return dst;
1318 }
1319
1320 RegisterID* BytecodeGenerator::emitPutByIndex(RegisterID* base, unsigned index, RegisterID* value)
1321 {
1322     emitOpcode(op_put_by_index);
1323     instructions().append(base->index());
1324     instructions().append(index);
1325     instructions().append(value->index());
1326     return value;
1327 }
1328
1329 RegisterID* BytecodeGenerator::emitNewObject(RegisterID* dst)
1330 {
1331     emitOpcode(op_new_object);
1332     instructions().append(dst->index());
1333     return dst;
1334 }
1335
1336 RegisterID* BytecodeGenerator::emitNewArray(RegisterID* dst, ElementNode* elements)
1337 {
1338     Vector<RefPtr<RegisterID>, 16> argv;
1339     for (ElementNode* n = elements; n; n = n->next()) {
1340         if (n->elision())
1341             break;
1342         argv.append(newTemporary());
1343         // op_new_array requires the initial values to be a sequential range of registers
1344         ASSERT(argv.size() == 1 || argv[argv.size() - 1]->index() == argv[argv.size() - 2]->index() + 1);
1345         emitNode(argv.last().get(), n->value());
1346     }
1347     emitOpcode(op_new_array);
1348     instructions().append(dst->index());
1349     instructions().append(argv.size() ? argv[0]->index() : 0); // argv
1350     instructions().append(argv.size()); // argc
1351     return dst;
1352 }
1353
1354 RegisterID* BytecodeGenerator::emitNewFunction(RegisterID* dst, FunctionBodyNode* function)
1355 {
1356     unsigned index = m_codeBlock->addFunctionDecl(makeFunction(m_globalData, function));
1357
1358     emitOpcode(op_new_func);
1359     instructions().append(dst->index());
1360     instructions().append(index);
1361     return dst;
1362 }
1363
1364 RegisterID* BytecodeGenerator::emitNewRegExp(RegisterID* dst, RegExp* regExp)
1365 {
1366     emitOpcode(op_new_regexp);
1367     instructions().append(dst->index());
1368     instructions().append(addRegExp(regExp));
1369     return dst;
1370 }
1371
1372
1373 RegisterID* BytecodeGenerator::emitNewFunctionExpression(RegisterID* r0, FuncExprNode* n)
1374 {
1375     FunctionBodyNode* function = n->body();
1376     unsigned index = m_codeBlock->addFunctionExpr(makeFunction(m_globalData, function));
1377
1378     emitOpcode(op_new_func_exp);
1379     instructions().append(r0->index());
1380     instructions().append(index);
1381     return r0;
1382 }
1383
1384 RegisterID* BytecodeGenerator::emitCall(RegisterID* dst, RegisterID* func, RegisterID* thisRegister, ArgumentsNode* argumentsNode, unsigned divot, unsigned startOffset, unsigned endOffset)
1385 {
1386     return emitCall(op_call, dst, func, thisRegister, argumentsNode, divot, startOffset, endOffset);
1387 }
1388
1389 void BytecodeGenerator::createArgumentsIfNecessary()
1390 {
1391     if (m_codeBlock->usesArguments() && m_codeType == FunctionCode)
1392         emitOpcode(op_create_arguments);
1393 }
1394
1395 RegisterID* BytecodeGenerator::emitCallEval(RegisterID* dst, RegisterID* func, RegisterID* thisRegister, ArgumentsNode* argumentsNode, unsigned divot, unsigned startOffset, unsigned endOffset)
1396 {
1397     createArgumentsIfNecessary();
1398     return emitCall(op_call_eval, dst, func, thisRegister, argumentsNode, divot, startOffset, endOffset);
1399 }
1400
1401 RegisterID* BytecodeGenerator::emitCall(OpcodeID opcodeID, RegisterID* dst, RegisterID* func, RegisterID* thisRegister, ArgumentsNode* argumentsNode, unsigned divot, unsigned startOffset, unsigned endOffset)
1402 {
1403     ASSERT(opcodeID == op_call || opcodeID == op_call_eval);
1404     ASSERT(func->refCount());
1405     ASSERT(thisRegister->refCount());
1406
1407     RegisterID* originalFunc = func;
1408     if (m_shouldEmitProfileHooks) {
1409         // If codegen decided to recycle func as this call's destination register,
1410         // we need to undo that optimization here so that func will still be around
1411         // for the sake of op_profile_did_call.
1412         if (dst == func) {
1413             RefPtr<RegisterID> movedThisRegister = emitMove(newTemporary(), thisRegister);
1414             RefPtr<RegisterID> movedFunc = emitMove(thisRegister, func);
1415
1416             thisRegister = movedThisRegister.release().releaseRef();
1417             func = movedFunc.release().releaseRef();
1418         }
1419     }
1420
1421     // Generate code for arguments.
1422     Vector<RefPtr<RegisterID>, 16> argv;
1423     argv.append(thisRegister);
1424     for (ArgumentListNode* n = argumentsNode->m_listNode; n; n = n->m_next) {
1425         argv.append(newTemporary());
1426         // op_call requires the arguments to be a sequential range of registers
1427         ASSERT(argv[argv.size() - 1]->index() == argv[argv.size() - 2]->index() + 1);
1428         emitNode(argv.last().get(), n);
1429     }
1430
1431     // Reserve space for call frame.
1432     Vector<RefPtr<RegisterID>, RegisterFile::CallFrameHeaderSize> callFrame;
1433     for (int i = 0; i < RegisterFile::CallFrameHeaderSize; ++i)
1434         callFrame.append(newTemporary());
1435
1436     if (m_shouldEmitProfileHooks) {
1437         emitOpcode(op_profile_will_call);
1438         instructions().append(func->index());
1439
1440 #if ENABLE(JIT)
1441         m_codeBlock->addFunctionRegisterInfo(instructions().size(), func->index());
1442 #endif
1443     }
1444
1445     emitExpressionInfo(divot, startOffset, endOffset);
1446
1447 #if ENABLE(JIT)
1448     m_codeBlock->addCallLinkInfo();
1449 #endif
1450
1451     // Emit call.
1452     emitOpcode(opcodeID);
1453     instructions().append(dst->index()); // dst
1454     instructions().append(func->index()); // func
1455     instructions().append(argv.size()); // argCount
1456     instructions().append(argv[0]->index() + argv.size() + RegisterFile::CallFrameHeaderSize); // registerOffset
1457
1458     if (m_shouldEmitProfileHooks) {
1459         emitOpcode(op_profile_did_call);
1460         instructions().append(func->index());
1461
1462         if (dst == originalFunc) {
1463             thisRegister->deref();
1464             func->deref();
1465         }
1466     }
1467
1468     return dst;
1469 }
1470
1471 RegisterID* BytecodeGenerator::emitLoadVarargs(RegisterID* argCountDst, RegisterID* arguments)
1472 {
1473     ASSERT(argCountDst->index() < arguments->index());
1474     emitOpcode(op_load_varargs);
1475     instructions().append(argCountDst->index());
1476     instructions().append(arguments->index());
1477     return argCountDst;
1478 }
1479
1480 RegisterID* BytecodeGenerator::emitCallVarargs(RegisterID* dst, RegisterID* func, RegisterID* thisRegister, RegisterID* argCountRegister, unsigned divot, unsigned startOffset, unsigned endOffset)
1481 {
1482     ASSERT(func->refCount());
1483     ASSERT(thisRegister->refCount());
1484     ASSERT(dst != func);
1485     if (m_shouldEmitProfileHooks) {
1486         emitOpcode(op_profile_will_call);
1487         instructions().append(func->index());
1488
1489 #if ENABLE(JIT)
1490         m_codeBlock->addFunctionRegisterInfo(instructions().size(), func->index());
1491 #endif
1492     }
1493
1494     emitExpressionInfo(divot, startOffset, endOffset);
1495
1496     // Emit call.
1497     emitOpcode(op_call_varargs);
1498     instructions().append(dst->index()); // dst
1499     instructions().append(func->index()); // func
1500     instructions().append(argCountRegister->index()); // arg count
1501     instructions().append(thisRegister->index() + RegisterFile::CallFrameHeaderSize); // initial registerOffset
1502     if (m_shouldEmitProfileHooks) {
1503         emitOpcode(op_profile_did_call);
1504         instructions().append(func->index());
1505     }
1506     return dst;
1507 }
1508
1509 RegisterID* BytecodeGenerator::emitReturn(RegisterID* src)
1510 {
1511     if (m_codeBlock->needsFullScopeChain()) {
1512         emitOpcode(op_tear_off_activation);
1513         instructions().append(m_activationRegisterIndex);
1514     } else if (m_codeBlock->usesArguments() && m_codeBlock->m_numParameters > 1)
1515         emitOpcode(op_tear_off_arguments);
1516
1517     return emitUnaryNoDstOp(op_ret, src);
1518 }
1519
1520 RegisterID* BytecodeGenerator::emitUnaryNoDstOp(OpcodeID opcodeID, RegisterID* src)
1521 {
1522     emitOpcode(opcodeID);
1523     instructions().append(src->index());
1524     return src;
1525 }
1526
1527 RegisterID* BytecodeGenerator::emitConstruct(RegisterID* dst, RegisterID* func, ArgumentsNode* argumentsNode, unsigned divot, unsigned startOffset, unsigned endOffset)
1528 {
1529     ASSERT(func->refCount());
1530
1531     RegisterID* originalFunc = func;
1532     if (m_shouldEmitProfileHooks) {
1533         // If codegen decided to recycle func as this call's destination register,
1534         // we need to undo that optimization here so that func will still be around
1535         // for the sake of op_profile_did_call.
1536         if (dst == func) {
1537             RefPtr<RegisterID> movedFunc = emitMove(newTemporary(), func);
1538             func = movedFunc.release().releaseRef();
1539         }
1540     }
1541
1542     RefPtr<RegisterID> funcProto = newTemporary();
1543
1544     // Generate code for arguments.
1545     Vector<RefPtr<RegisterID>, 16> argv;
1546     argv.append(newTemporary()); // reserve space for "this"
1547     for (ArgumentListNode* n = argumentsNode ? argumentsNode->m_listNode : 0; n; n = n->m_next) {
1548         argv.append(newTemporary());
1549         // op_construct requires the arguments to be a sequential range of registers
1550         ASSERT(argv[argv.size() - 1]->index() == argv[argv.size() - 2]->index() + 1);
1551         emitNode(argv.last().get(), n);
1552     }
1553
1554     if (m_shouldEmitProfileHooks) {
1555         emitOpcode(op_profile_will_call);
1556         instructions().append(func->index());
1557     }
1558
1559     // Load prototype.
1560     emitExpressionInfo(divot, startOffset, endOffset);
1561     emitGetByIdExceptionInfo(op_construct);
1562     emitGetById(funcProto.get(), func, globalData()->propertyNames->prototype);
1563
1564     // Reserve space for call frame.
1565     Vector<RefPtr<RegisterID>, RegisterFile::CallFrameHeaderSize> callFrame;
1566     for (int i = 0; i < RegisterFile::CallFrameHeaderSize; ++i)
1567         callFrame.append(newTemporary());
1568
1569     emitExpressionInfo(divot, startOffset, endOffset);
1570
1571 #if ENABLE(JIT)
1572     m_codeBlock->addCallLinkInfo();
1573 #endif
1574
1575     emitOpcode(op_construct);
1576     instructions().append(dst->index()); // dst
1577     instructions().append(func->index()); // func
1578     instructions().append(argv.size()); // argCount
1579     instructions().append(argv[0]->index() + argv.size() + RegisterFile::CallFrameHeaderSize); // registerOffset
1580     instructions().append(funcProto->index()); // proto
1581     instructions().append(argv[0]->index()); // thisRegister
1582
1583     emitOpcode(op_construct_verify);
1584     instructions().append(dst->index());
1585     instructions().append(argv[0]->index());
1586
1587     if (m_shouldEmitProfileHooks) {
1588         emitOpcode(op_profile_did_call);
1589         instructions().append(func->index());
1590
1591         if (dst == originalFunc)
1592             func->deref();
1593     }
1594
1595     return dst;
1596 }
1597
1598 RegisterID* BytecodeGenerator::emitStrcat(RegisterID* dst, RegisterID* src, int count)
1599 {
1600     emitOpcode(op_strcat);
1601     instructions().append(dst->index());
1602     instructions().append(src->index());
1603     instructions().append(count);
1604
1605     return dst;
1606 }
1607
1608 void BytecodeGenerator::emitToPrimitive(RegisterID* dst, RegisterID* src)
1609 {
1610     emitOpcode(op_to_primitive);
1611     instructions().append(dst->index());
1612     instructions().append(src->index());
1613 }
1614
1615 RegisterID* BytecodeGenerator::emitPushScope(RegisterID* scope)
1616 {
1617     ASSERT(scope->isTemporary());
1618     ControlFlowContext context;
1619     context.isFinallyBlock = false;
1620     m_scopeContextStack.append(context);
1621     m_dynamicScopeDepth++;
1622     createArgumentsIfNecessary();
1623
1624     return emitUnaryNoDstOp(op_push_scope, scope);
1625 }
1626
1627 void BytecodeGenerator::emitPopScope()
1628 {
1629     ASSERT(m_scopeContextStack.size());
1630     ASSERT(!m_scopeContextStack.last().isFinallyBlock);
1631
1632     emitOpcode(op_pop_scope);
1633
1634     m_scopeContextStack.removeLast();
1635     m_dynamicScopeDepth--;
1636 }
1637
1638 void BytecodeGenerator::emitDebugHook(DebugHookID debugHookID, int firstLine, int lastLine)
1639 {
1640     if (!m_shouldEmitDebugHooks)
1641         return;
1642     emitOpcode(op_debug);
1643     instructions().append(debugHookID);
1644     instructions().append(firstLine);
1645     instructions().append(lastLine);
1646 }
1647
1648 void BytecodeGenerator::pushFinallyContext(Label* target, RegisterID* retAddrDst)
1649 {
1650     ControlFlowContext scope;
1651     scope.isFinallyBlock = true;
1652     FinallyContext context = { target, retAddrDst };
1653     scope.finallyContext = context;
1654     m_scopeContextStack.append(scope);
1655     m_finallyDepth++;
1656 }
1657
1658 void BytecodeGenerator::popFinallyContext()
1659 {
1660     ASSERT(m_scopeContextStack.size());
1661     ASSERT(m_scopeContextStack.last().isFinallyBlock);
1662     ASSERT(m_finallyDepth > 0);
1663     m_scopeContextStack.removeLast();
1664     m_finallyDepth--;
1665 }
1666
1667 LabelScope* BytecodeGenerator::breakTarget(const Identifier& name)
1668 {
1669     // Reclaim free label scopes.
1670     //
1671     // The condition was previously coded as 'm_labelScopes.size() && !m_labelScopes.last().refCount()',
1672     // however sometimes this appears to lead to GCC going a little haywire and entering the loop with
1673     // size 0, leading to segfaulty badness.  We are yet to identify a valid cause within our code to
1674     // cause the GCC codegen to misbehave in this fashion, and as such the following refactoring of the
1675     // loop condition is a workaround.
1676     while (m_labelScopes.size()) {
1677         if  (m_labelScopes.last().refCount())
1678             break;
1679         m_labelScopes.removeLast();
1680     }
1681
1682     if (!m_labelScopes.size())
1683         return 0;
1684
1685     // We special-case the following, which is a syntax error in Firefox:
1686     // label:
1687     //     break;
1688     if (name.isEmpty()) {
1689         for (int i = m_labelScopes.size() - 1; i >= 0; --i) {
1690             LabelScope* scope = &m_labelScopes[i];
1691             if (scope->type() != LabelScope::NamedLabel) {
1692                 ASSERT(scope->breakTarget());
1693                 return scope;
1694             }
1695         }
1696         return 0;
1697     }
1698
1699     for (int i = m_labelScopes.size() - 1; i >= 0; --i) {
1700         LabelScope* scope = &m_labelScopes[i];
1701         if (scope->name() && *scope->name() == name) {
1702             ASSERT(scope->breakTarget());
1703             return scope;
1704         }
1705     }
1706     return 0;
1707 }
1708
1709 LabelScope* BytecodeGenerator::continueTarget(const Identifier& name)
1710 {
1711     // Reclaim free label scopes.
1712     while (m_labelScopes.size() && !m_labelScopes.last().refCount())
1713         m_labelScopes.removeLast();
1714
1715     if (!m_labelScopes.size())
1716         return 0;
1717
1718     if (name.isEmpty()) {
1719         for (int i = m_labelScopes.size() - 1; i >= 0; --i) {
1720             LabelScope* scope = &m_labelScopes[i];
1721             if (scope->type() == LabelScope::Loop) {
1722                 ASSERT(scope->continueTarget());
1723                 return scope;
1724             }
1725         }
1726         return 0;
1727     }
1728
1729     // Continue to the loop nested nearest to the label scope that matches
1730     // 'name'.
1731     LabelScope* result = 0;
1732     for (int i = m_labelScopes.size() - 1; i >= 0; --i) {
1733         LabelScope* scope = &m_labelScopes[i];
1734         if (scope->type() == LabelScope::Loop) {
1735             ASSERT(scope->continueTarget());
1736             result = scope;
1737         }
1738         if (scope->name() && *scope->name() == name)
1739             return result; // may be 0
1740     }
1741     return 0;
1742 }
1743
1744 PassRefPtr<Label> BytecodeGenerator::emitComplexJumpScopes(Label* target, ControlFlowContext* topScope, ControlFlowContext* bottomScope)
1745 {
1746     while (topScope > bottomScope) {
1747         // First we count the number of dynamic scopes we need to remove to get
1748         // to a finally block.
1749         int nNormalScopes = 0;
1750         while (topScope > bottomScope) {
1751             if (topScope->isFinallyBlock)
1752                 break;
1753             ++nNormalScopes;
1754             --topScope;
1755         }
1756
1757         if (nNormalScopes) {
1758             size_t begin = instructions().size();
1759
1760             // We need to remove a number of dynamic scopes to get to the next
1761             // finally block
1762             emitOpcode(op_jmp_scopes);
1763             instructions().append(nNormalScopes);
1764
1765             // If topScope == bottomScope then there isn't actually a finally block
1766             // left to emit, so make the jmp_scopes jump directly to the target label
1767             if (topScope == bottomScope) {
1768                 instructions().append(target->bind(begin, instructions().size()));
1769                 return target;
1770             }
1771
1772             // Otherwise we just use jmp_scopes to pop a group of scopes and go
1773             // to the next instruction
1774             RefPtr<Label> nextInsn = newLabel();
1775             instructions().append(nextInsn->bind(begin, instructions().size()));
1776             emitLabel(nextInsn.get());
1777         }
1778
1779         while (topScope > bottomScope && topScope->isFinallyBlock) {
1780             emitJumpSubroutine(topScope->finallyContext.retAddrDst, topScope->finallyContext.finallyAddr);
1781             --topScope;
1782         }
1783     }
1784     return emitJump(target);
1785 }
1786
1787 PassRefPtr<Label> BytecodeGenerator::emitJumpScopes(Label* target, int targetScopeDepth)
1788 {
1789     ASSERT(scopeDepth() - targetScopeDepth >= 0);
1790     ASSERT(target->isForward());
1791
1792     size_t scopeDelta = scopeDepth() - targetScopeDepth;
1793     ASSERT(scopeDelta <= m_scopeContextStack.size());
1794     if (!scopeDelta)
1795         return emitJump(target);
1796
1797     if (m_finallyDepth)
1798         return emitComplexJumpScopes(target, &m_scopeContextStack.last(), &m_scopeContextStack.last() - scopeDelta);
1799
1800     size_t begin = instructions().size();
1801
1802     emitOpcode(op_jmp_scopes);
1803     instructions().append(scopeDelta);
1804     instructions().append(target->bind(begin, instructions().size()));
1805     return target;
1806 }
1807
1808 RegisterID* BytecodeGenerator::emitGetPropertyNames(RegisterID* dst, RegisterID* base, RegisterID* i, RegisterID* size, Label* breakTarget)
1809 {
1810     size_t begin = instructions().size();
1811
1812     emitOpcode(op_get_pnames);
1813     instructions().append(dst->index());
1814     instructions().append(base->index());
1815     instructions().append(i->index());
1816     instructions().append(size->index());
1817     instructions().append(breakTarget->bind(begin, instructions().size()));
1818     return dst;
1819 }
1820
1821 RegisterID* BytecodeGenerator::emitNextPropertyName(RegisterID* dst, RegisterID* base, RegisterID* i, RegisterID* size, RegisterID* iter, Label* target)
1822 {
1823     size_t begin = instructions().size();
1824
1825     emitOpcode(op_next_pname);
1826     instructions().append(dst->index());
1827     instructions().append(base->index());
1828     instructions().append(i->index());
1829     instructions().append(size->index());
1830     instructions().append(iter->index());
1831     instructions().append(target->bind(begin, instructions().size()));
1832     return dst;
1833 }
1834
1835 RegisterID* BytecodeGenerator::emitCatch(RegisterID* targetRegister, Label* start, Label* end)
1836 {
1837 #if ENABLE(JIT)
1838     HandlerInfo info = { start->bind(0, 0), end->bind(0, 0), instructions().size(), m_dynamicScopeDepth + m_baseScopeDepth, CodeLocationLabel() };
1839 #else
1840     HandlerInfo info = { start->bind(0, 0), end->bind(0, 0), instructions().size(), m_dynamicScopeDepth + m_baseScopeDepth };
1841 #endif
1842
1843     m_codeBlock->addExceptionHandler(info);
1844     emitOpcode(op_catch);
1845     instructions().append(targetRegister->index());
1846     return targetRegister;
1847 }
1848
1849 RegisterID* BytecodeGenerator::emitNewError(RegisterID* dst, ErrorType type, JSValue message)
1850 {
1851     emitOpcode(op_new_error);
1852     instructions().append(dst->index());
1853     instructions().append(static_cast<int>(type));
1854     instructions().append(addConstantValue(message)->index());
1855     return dst;
1856 }
1857
1858 PassRefPtr<Label> BytecodeGenerator::emitJumpSubroutine(RegisterID* retAddrDst, Label* finally)
1859 {
1860     size_t begin = instructions().size();
1861
1862     emitOpcode(op_jsr);
1863     instructions().append(retAddrDst->index());
1864     instructions().append(finally->bind(begin, instructions().size()));
1865     emitLabel(newLabel().get()); // Record the fact that the next instruction is implicitly labeled, because op_sret will return to it.
1866     return finally;
1867 }
1868
1869 void BytecodeGenerator::emitSubroutineReturn(RegisterID* retAddrSrc)
1870 {
1871     emitOpcode(op_sret);
1872     instructions().append(retAddrSrc->index());
1873 }
1874
1875 void BytecodeGenerator::emitPushNewScope(RegisterID* dst, const Identifier& property, RegisterID* value)
1876 {
1877     ControlFlowContext context;
1878     context.isFinallyBlock = false;
1879     m_scopeContextStack.append(context);
1880     m_dynamicScopeDepth++;
1881
1882     createArgumentsIfNecessary();
1883
1884     emitOpcode(op_push_new_scope);
1885     instructions().append(dst->index());
1886     instructions().append(addConstant(property));
1887     instructions().append(value->index());
1888 }
1889
1890 void BytecodeGenerator::beginSwitch(RegisterID* scrutineeRegister, SwitchInfo::SwitchType type)
1891 {
1892     SwitchInfo info = { instructions().size(), type };
1893     switch (type) {
1894         case SwitchInfo::SwitchImmediate:
1895             emitOpcode(op_switch_imm);
1896             break;
1897         case SwitchInfo::SwitchCharacter:
1898             emitOpcode(op_switch_char);
1899             break;
1900         case SwitchInfo::SwitchString:
1901             emitOpcode(op_switch_string);
1902             break;
1903         default:
1904             ASSERT_NOT_REACHED();
1905     }
1906
1907     instructions().append(0); // place holder for table index
1908     instructions().append(0); // place holder for default target
1909     instructions().append(scrutineeRegister->index());
1910     m_switchContextStack.append(info);
1911 }
1912
1913 static int32_t keyForImmediateSwitch(ExpressionNode* node, int32_t min, int32_t max)
1914 {
1915     UNUSED_PARAM(max);
1916     ASSERT(node->isNumber());
1917     double value = static_cast<NumberNode*>(node)->value();
1918     int32_t key = static_cast<int32_t>(value);
1919     ASSERT(key == value);
1920     ASSERT(key >= min);
1921     ASSERT(key <= max);
1922     return key - min;
1923 }
1924
1925 static void prepareJumpTableForImmediateSwitch(SimpleJumpTable& jumpTable, int32_t switchAddress, uint32_t clauseCount, RefPtr<Label>* labels, ExpressionNode** nodes, int32_t min, int32_t max)
1926 {
1927     jumpTable.min = min;
1928     jumpTable.branchOffsets.resize(max - min + 1);
1929     jumpTable.branchOffsets.fill(0);
1930     for (uint32_t i = 0; i < clauseCount; ++i) {
1931         // We're emitting this after the clause labels should have been fixed, so
1932         // the labels should not be "forward" references
1933         ASSERT(!labels[i]->isForward());
1934         jumpTable.add(keyForImmediateSwitch(nodes[i], min, max), labels[i]->bind(switchAddress, switchAddress + 3));
1935     }
1936 }
1937
1938 static int32_t keyForCharacterSwitch(ExpressionNode* node, int32_t min, int32_t max)
1939 {
1940     UNUSED_PARAM(max);
1941     ASSERT(node->isString());
1942     UString::Rep* clause = static_cast<StringNode*>(node)->value().ustring().rep();
1943     ASSERT(clause->size() == 1);
1944
1945     int32_t key = clause->data()[0];
1946     ASSERT(key >= min);
1947     ASSERT(key <= max);
1948     return key - min;
1949 }
1950
1951 static void prepareJumpTableForCharacterSwitch(SimpleJumpTable& jumpTable, int32_t switchAddress, uint32_t clauseCount, RefPtr<Label>* labels, ExpressionNode** nodes, int32_t min, int32_t max)
1952 {
1953     jumpTable.min = min;
1954     jumpTable.branchOffsets.resize(max - min + 1);
1955     jumpTable.branchOffsets.fill(0);
1956     for (uint32_t i = 0; i < clauseCount; ++i) {
1957         // We're emitting this after the clause labels should have been fixed, so
1958         // the labels should not be "forward" references
1959         ASSERT(!labels[i]->isForward());
1960         jumpTable.add(keyForCharacterSwitch(nodes[i], min, max), labels[i]->bind(switchAddress, switchAddress + 3));
1961     }
1962 }
1963
1964 static void prepareJumpTableForStringSwitch(StringJumpTable& jumpTable, int32_t switchAddress, uint32_t clauseCount, RefPtr<Label>* labels, ExpressionNode** nodes)
1965 {
1966     for (uint32_t i = 0; i < clauseCount; ++i) {
1967         // We're emitting this after the clause labels should have been fixed, so
1968         // the labels should not be "forward" references
1969         ASSERT(!labels[i]->isForward());
1970
1971         ASSERT(nodes[i]->isString());
1972         UString::Rep* clause = static_cast<StringNode*>(nodes[i])->value().ustring().rep();
1973         OffsetLocation location;
1974         location.branchOffset = labels[i]->bind(switchAddress, switchAddress + 3);
1975         jumpTable.offsetTable.add(clause, location);
1976     }
1977 }
1978
1979 void BytecodeGenerator::endSwitch(uint32_t clauseCount, RefPtr<Label>* labels, ExpressionNode** nodes, Label* defaultLabel, int32_t min, int32_t max)
1980 {
1981     SwitchInfo switchInfo = m_switchContextStack.last();
1982     m_switchContextStack.removeLast();
1983     if (switchInfo.switchType == SwitchInfo::SwitchImmediate) {
1984         instructions()[switchInfo.bytecodeOffset + 1] = m_codeBlock->numberOfImmediateSwitchJumpTables();
1985         instructions()[switchInfo.bytecodeOffset + 2] = defaultLabel->bind(switchInfo.bytecodeOffset, switchInfo.bytecodeOffset + 3);
1986
1987         SimpleJumpTable& jumpTable = m_codeBlock->addImmediateSwitchJumpTable();
1988         prepareJumpTableForImmediateSwitch(jumpTable, switchInfo.bytecodeOffset, clauseCount, labels, nodes, min, max);
1989     } else if (switchInfo.switchType == SwitchInfo::SwitchCharacter) {
1990         instructions()[switchInfo.bytecodeOffset + 1] = m_codeBlock->numberOfCharacterSwitchJumpTables();
1991         instructions()[switchInfo.bytecodeOffset + 2] = defaultLabel->bind(switchInfo.bytecodeOffset, switchInfo.bytecodeOffset + 3);
1992
1993         SimpleJumpTable& jumpTable = m_codeBlock->addCharacterSwitchJumpTable();
1994         prepareJumpTableForCharacterSwitch(jumpTable, switchInfo.bytecodeOffset, clauseCount, labels, nodes, min, max);
1995     } else {
1996         ASSERT(switchInfo.switchType == SwitchInfo::SwitchString);
1997         instructions()[switchInfo.bytecodeOffset + 1] = m_codeBlock->numberOfStringSwitchJumpTables();
1998         instructions()[switchInfo.bytecodeOffset + 2] = defaultLabel->bind(switchInfo.bytecodeOffset, switchInfo.bytecodeOffset + 3);
1999
2000         StringJumpTable& jumpTable = m_codeBlock->addStringSwitchJumpTable();
2001         prepareJumpTableForStringSwitch(jumpTable, switchInfo.bytecodeOffset, clauseCount, labels, nodes);
2002     }
2003 }
2004
2005 RegisterID* BytecodeGenerator::emitThrowExpressionTooDeepException()
2006 {
2007     // It would be nice to do an even better job of identifying exactly where the expression is.
2008     // And we could make the caller pass the node pointer in, if there was some way of getting
2009     // that from an arbitrary node. However, calling emitExpressionInfo without any useful data
2010     // is still good enough to get us an accurate line number.
2011     emitExpressionInfo(0, 0, 0);
2012     RegisterID* exception = emitNewError(newTemporary(), SyntaxError, jsString(globalData(), "Expression too deep"));
2013     emitThrow(exception);
2014     return exception;
2015 }
2016
2017 } // namespace JSC