Merge WebKit at r75315: Initial merge by git.

Change-Id: I570314b346ce101c935ed22a626b48c2af266b84

6 files changed, 5187 insertions, 0 deletions

diff --git a/Source/JavaScriptCore/bytecompiler/BytecodeGenerator.cpp b/Source/JavaScriptCore/bytecompiler/BytecodeGenerator.cpp
new file mode 100644
index 0000000..3a99957
--- /dev/null
+++ b/Source/JavaScriptCore/bytecompiler/BytecodeGenerator.cpp
@@ -0,0 +1,2233 @@
+/*
+ * Copyright (C) 2008, 2009 Apple Inc. All rights reserved.
+ * Copyright (C) 2008 Cameron Zwarich <cwzwarich@uwaterloo.ca>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1.  Redistributions of source code must retain the above copyright
+ *     notice, this list of conditions and the following disclaimer.
+ * 2.  Redistributions in binary form must reproduce the above copyright
+ *     notice, this list of conditions and the following disclaimer in the
+ *     documentation and/or other materials provided with the distribution.
+ * 3.  Neither the name of Apple Computer, Inc. ("Apple") nor the names of
+ *     its contributors may be used to endorse or promote products derived
+ *     from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "config.h"
+#include "BytecodeGenerator.h"
+
+#include "BatchedTransitionOptimizer.h"
+#include "PrototypeFunction.h"
+#include "JSFunction.h"
+#include "Interpreter.h"
+#include "UString.h"
+
+using namespace std;
+
+namespace JSC {
+
+/*
+    The layout of a register frame looks like this:
+
+    For
+
+    function f(x, y) {
+        var v1;
+        function g() { }
+        var v2;
+        return (x) * (y);
+    }
+
+    assuming (x) and (y) generated temporaries t1 and t2, you would have
+
+    ------------------------------------
+    |  x |  y |  g | v2 | v1 | t1 | t2 | <-- value held
+    ------------------------------------
+    | -5 | -4 | -3 | -2 | -1 | +0 | +1 | <-- register index
+    ------------------------------------
+    | params->|<-locals      | temps->
+
+    Because temporary registers are allocated in a stack-like fashion, we
+    can reclaim them with a simple popping algorithm. The same goes for labels.
+    (We never reclaim parameter or local registers, because parameters and
+    locals are DontDelete.)
+
+    The register layout before a function call looks like this:
+
+    For
+
+    function f(x, y)
+    {
+    }
+
+    f(1);
+
+    >                        <------------------------------
+    <                        >  reserved: call frame  |  1 | <-- value held
+    >         >snip<         <------------------------------
+    <                        > +0 | +1 | +2 | +3 | +4 | +5 | <-- register index
+    >                        <------------------------------
+    | params->|<-locals      | temps->
+
+    The call instruction fills in the "call frame" registers. It also pads
+    missing arguments at the end of the call:
+
+    >                        <-----------------------------------
+    <                        >  reserved: call frame  |  1 |  ? | <-- value held ("?" stands for "undefined")
+    >         >snip<         <-----------------------------------
+    <                        > +0 | +1 | +2 | +3 | +4 | +5 | +6 | <-- register index
+    >                        <-----------------------------------
+    | params->|<-locals      | temps->
+
+    After filling in missing arguments, the call instruction sets up the new
+    stack frame to overlap the end of the old stack frame:
+
+                             |---------------------------------->                        <
+                             |  reserved: call frame  |  1 |  ? <                        > <-- value held ("?" stands for "undefined")
+                             |---------------------------------->         >snip<         <
+                             | -7 | -6 | -5 | -4 | -3 | -2 | -1 <                        > <-- register index
+                             |---------------------------------->                        <
+                             |                        | params->|<-locals       | temps->
+
+    That way, arguments are "copied" into the callee's stack frame for free.
+
+    If the caller supplies too many arguments, this trick doesn't work. The
+    extra arguments protrude into space reserved for locals and temporaries.
+    In that case, the call instruction makes a real copy of the call frame header,
+    along with just the arguments expected by the callee, leaving the original
+    call frame header and arguments behind. (The call instruction can't just discard
+    extra arguments, because the "arguments" object may access them later.)
+    This copying strategy ensures that all named values will be at the indices
+    expected by the callee.
+*/
+
+#ifndef NDEBUG
+static bool s_dumpsGeneratedCode = false;
+#endif
+
+void BytecodeGenerator::setDumpsGeneratedCode(bool dumpsGeneratedCode)
+{
+#ifndef NDEBUG
+    s_dumpsGeneratedCode = dumpsGeneratedCode;
+#else
+    UNUSED_PARAM(dumpsGeneratedCode);
+#endif
+}
+
+bool BytecodeGenerator::dumpsGeneratedCode()
+{
+#ifndef NDEBUG
+    return s_dumpsGeneratedCode;
+#else
+    return false;
+#endif
+}
+
+void BytecodeGenerator::generate()
+{
+    m_codeBlock->setThisRegister(m_thisRegister.index());
+
+    m_scopeNode->emitBytecode(*this);
+
+#ifndef NDEBUG
+    m_codeBlock->setInstructionCount(m_codeBlock->instructions().size());
+
+    if (s_dumpsGeneratedCode)
+        m_codeBlock->dump(m_scopeChain->globalObject()->globalExec());
+#endif
+
+    if ((m_codeType == FunctionCode && !m_codeBlock->needsFullScopeChain() && !m_codeBlock->usesArguments()) || m_codeType == EvalCode)
+        symbolTable().clear();
+
+    m_codeBlock->shrinkToFit();
+}
+
+bool BytecodeGenerator::addVar(const Identifier& ident, bool isConstant, RegisterID*& r0)
+{
+    int index = m_calleeRegisters.size();
+    SymbolTableEntry newEntry(index, isConstant ? ReadOnly : 0);
+    pair<SymbolTable::iterator, bool> result = symbolTable().add(ident.impl(), newEntry);
+
+    if (!result.second) {
+        r0 = &registerFor(result.first->second.getIndex());
+        return false;
+    }
+
+    r0 = addVar();
+    return true;
+}
+
+bool BytecodeGenerator::addGlobalVar(const Identifier& ident, bool isConstant, RegisterID*& r0)
+{
+    int index = m_nextGlobalIndex;
+    SymbolTableEntry newEntry(index, isConstant ? ReadOnly : 0);
+    pair<SymbolTable::iterator, bool> result = symbolTable().add(ident.impl(), newEntry);
+
+    if (!result.second)
+        index = result.first->second.getIndex();
+    else {
+        --m_nextGlobalIndex;
+        m_globals.append(index + m_globalVarStorageOffset);
+    }
+
+    r0 = &registerFor(index);
+    return result.second;
+}
+
+void BytecodeGenerator::preserveLastVar()
+{
+    if ((m_firstConstantIndex = m_calleeRegisters.size()) != 0)
+        m_lastVar = &m_calleeRegisters.last();
+}
+
+BytecodeGenerator::BytecodeGenerator(ProgramNode* programNode, const ScopeChain& scopeChain, SymbolTable* symbolTable, ProgramCodeBlock* codeBlock)
+    : m_shouldEmitDebugHooks(scopeChain.globalObject()->debugger())
+    , m_shouldEmitProfileHooks(scopeChain.globalObject()->supportsProfiling())
+    , m_shouldEmitRichSourceInfo(scopeChain.globalObject()->supportsRichSourceInfo())
+    , m_scopeChain(&scopeChain)
+    , m_symbolTable(symbolTable)
+    , m_scopeNode(programNode)
+    , m_codeBlock(codeBlock)
+    , m_thisRegister(RegisterFile::ProgramCodeThisRegister)
+    , m_finallyDepth(0)
+    , m_dynamicScopeDepth(0)
+    , m_baseScopeDepth(0)
+    , m_codeType(GlobalCode)
+    , m_nextGlobalIndex(-1)
+    , m_nextConstantOffset(0)
+    , m_globalConstantIndex(0)
+    , m_hasCreatedActivation(true)
+    , m_firstLazyFunction(0)
+    , m_lastLazyFunction(0)
+    , m_globalData(&scopeChain.globalObject()->globalData())
+    , m_lastOpcodeID(op_end)
+#ifndef NDEBUG
+    , m_lastOpcodePosition(0)
+#endif
+    , m_stack(m_globalData->stack())
+    , m_usesExceptions(false)
+    , m_regeneratingForExceptionInfo(false)
+    , m_codeBlockBeingRegeneratedFrom(0)
+{
+    if (m_shouldEmitDebugHooks)
+        m_codeBlock->setNeedsFullScopeChain(true);
+
+    emitOpcode(op_enter);
+    codeBlock->setGlobalData(m_globalData);
+
+    // FIXME: Move code that modifies the global object to Interpreter::execute.
+    
+    m_codeBlock->m_numParameters = 1; // Allocate space for "this"
+
+    JSGlobalObject* globalObject = scopeChain.globalObject();
+    ExecState* exec = globalObject->globalExec();
+    RegisterFile* registerFile = &exec->globalData().interpreter->registerFile();
+    
+    // Shift register indexes in generated code to elide registers allocated by intermediate stack frames.
+    m_globalVarStorageOffset = -RegisterFile::CallFrameHeaderSize - m_codeBlock->m_numParameters - registerFile->size();
+
+    // Add previously defined symbols to bookkeeping.
+    m_globals.grow(symbolTable->size());
+    SymbolTable::iterator end = symbolTable->end();
+    for (SymbolTable::iterator it = symbolTable->begin(); it != end; ++it)
+        registerFor(it->second.getIndex()).setIndex(it->second.getIndex() + m_globalVarStorageOffset);
+        
+    BatchedTransitionOptimizer optimizer(globalObject);
+
+    const VarStack& varStack = programNode->varStack();
+    const FunctionStack& functionStack = programNode->functionStack();
+    bool canOptimizeNewGlobals = symbolTable->size() + functionStack.size() + varStack.size() < registerFile->maxGlobals();
+    if (canOptimizeNewGlobals) {
+        // Shift new symbols so they get stored prior to existing symbols.
+        m_nextGlobalIndex -= symbolTable->size();
+
+        for (size_t i = 0; i < functionStack.size(); ++i) {
+            FunctionBodyNode* function = functionStack[i];
+            globalObject->removeDirect(function->ident()); // Make sure our new function is not shadowed by an old property.
+            emitNewFunction(addGlobalVar(function->ident(), false), function);
+        }
+
+        Vector<RegisterID*, 32> newVars;
+        for (size_t i = 0; i < varStack.size(); ++i)
+            if (!globalObject->hasProperty(exec, *varStack[i].first))
+                newVars.append(addGlobalVar(*varStack[i].first, varStack[i].second & DeclarationStacks::IsConstant));
+
+        preserveLastVar();
+
+        for (size_t i = 0; i < newVars.size(); ++i)
+            emitLoad(newVars[i], jsUndefined());
+    } else {
+        for (size_t i = 0; i < functionStack.size(); ++i) {
+            FunctionBodyNode* function = functionStack[i];
+            globalObject->putWithAttributes(exec, function->ident(), new (exec) JSFunction(exec, makeFunction(exec, function), scopeChain.node()), DontDelete);
+        }
+        for (size_t i = 0; i < varStack.size(); ++i) {
+            if (globalObject->hasProperty(exec, *varStack[i].first))
+                continue;
+            int attributes = DontDelete;
+            if (varStack[i].second & DeclarationStacks::IsConstant)
+                attributes |= ReadOnly;
+            globalObject->putWithAttributes(exec, *varStack[i].first, jsUndefined(), attributes);
+        }
+
+        preserveLastVar();
+    }
+    codeBlock->m_numCapturedVars = codeBlock->m_numVars;
+}
+
+BytecodeGenerator::BytecodeGenerator(FunctionBodyNode* functionBody, const ScopeChain& scopeChain, SymbolTable* symbolTable, CodeBlock* codeBlock)
+    : m_shouldEmitDebugHooks(scopeChain.globalObject()->debugger())
+    , m_shouldEmitProfileHooks(scopeChain.globalObject()->supportsProfiling())
+    , m_shouldEmitRichSourceInfo(scopeChain.globalObject()->supportsRichSourceInfo())
+    , m_scopeChain(&scopeChain)
+    , m_symbolTable(symbolTable)
+    , m_scopeNode(functionBody)
+    , m_codeBlock(codeBlock)
+    , m_activationRegister(0)
+    , m_finallyDepth(0)
+    , m_dynamicScopeDepth(0)
+    , m_baseScopeDepth(0)
+    , m_codeType(FunctionCode)
+    , m_nextConstantOffset(0)
+    , m_globalConstantIndex(0)
+    , m_hasCreatedActivation(false)
+    , m_firstLazyFunction(0)
+    , m_lastLazyFunction(0)
+    , m_globalData(&scopeChain.globalObject()->globalData())
+    , m_lastOpcodeID(op_end)
+#ifndef NDEBUG
+    , m_lastOpcodePosition(0)
+#endif
+    , m_stack(m_globalData->stack())
+    , m_usesExceptions(false)
+    , m_regeneratingForExceptionInfo(false)
+    , m_codeBlockBeingRegeneratedFrom(0)
+{
+    if (m_shouldEmitDebugHooks)
+        m_codeBlock->setNeedsFullScopeChain(true);
+
+    codeBlock->setGlobalData(m_globalData);
+    
+    emitOpcode(op_enter);
+    if (m_codeBlock->needsFullScopeChain()) {
+        m_activationRegister = addVar();
+        emitInitLazyRegister(m_activationRegister);
+        m_codeBlock->setActivationRegister(m_activationRegister->index());
+    }
+
+    // Both op_tear_off_activation and op_tear_off_arguments tear off the 'arguments'
+    // object, if created.
+    if (m_codeBlock->needsFullScopeChain() || functionBody->usesArguments()) {
+        RegisterID* unmodifiedArgumentsRegister = addVar(); // Anonymous, so it can't be modified by user code.
+        RegisterID* argumentsRegister = addVar(propertyNames().arguments, false); // Can be changed by assigning to 'arguments'.
+
+        // We can save a little space by hard-coding the knowledge that the two
+        // 'arguments' values are stored in consecutive registers, and storing
+        // only the index of the assignable one.
+        codeBlock->setArgumentsRegister(argumentsRegister->index());
+        ASSERT_UNUSED(unmodifiedArgumentsRegister, unmodifiedArgumentsRegister->index() == JSC::unmodifiedArgumentsRegister(codeBlock->argumentsRegister()));
+
+        emitInitLazyRegister(argumentsRegister);
+        emitInitLazyRegister(unmodifiedArgumentsRegister);
+        
+        if (m_codeBlock->isStrictMode()) {
+            emitOpcode(op_create_arguments);
+            instructions().append(argumentsRegister->index());
+        }
+
+        // The debugger currently retrieves the arguments object from an activation rather than pulling
+        // it from a call frame.  In the long-term it should stop doing that (<rdar://problem/6911886>),
+        // but for now we force eager creation of the arguments object when debugging.
+        if (m_shouldEmitDebugHooks) {
+            emitOpcode(op_create_arguments);
+            instructions().append(argumentsRegister->index());
+        }
+    }
+
+    const DeclarationStacks::FunctionStack& functionStack = functionBody->functionStack();
+    const DeclarationStacks::VarStack& varStack = functionBody->varStack();
+
+    // Captured variables and functions go first so that activations don't have
+    // to step over the non-captured locals to mark them.
+    m_hasCreatedActivation = false;
+    if (functionBody->hasCapturedVariables()) {
+        for (size_t i = 0; i < functionStack.size(); ++i) {
+            FunctionBodyNode* function = functionStack[i];
+            const Identifier& ident = function->ident();
+            if (functionBody->captures(ident)) {
+                if (!m_hasCreatedActivation) {
+                    m_hasCreatedActivation = true;
+                    emitOpcode(op_create_activation);
+                    instructions().append(m_activationRegister->index());
+                }
+                m_functions.add(ident.impl());
+                emitNewFunction(addVar(ident, false), function);
+            }
+        }
+        for (size_t i = 0; i < varStack.size(); ++i) {
+            const Identifier& ident = *varStack[i].first;
+            if (functionBody->captures(ident))
+                addVar(ident, varStack[i].second & DeclarationStacks::IsConstant);
+        }
+    }
+    bool canLazilyCreateFunctions = !functionBody->needsActivationForMoreThanVariables() && !m_shouldEmitDebugHooks;
+    if (!canLazilyCreateFunctions && !m_hasCreatedActivation) {
+        m_hasCreatedActivation = true;
+        emitOpcode(op_create_activation);
+        instructions().append(m_activationRegister->index());
+    }
+
+    codeBlock->m_numCapturedVars = codeBlock->m_numVars;
+    m_firstLazyFunction = codeBlock->m_numVars;
+    for (size_t i = 0; i < functionStack.size(); ++i) {
+        FunctionBodyNode* function = functionStack[i];
+        const Identifier& ident = function->ident();
+        if (!functionBody->captures(ident)) {
+            m_functions.add(ident.impl());
+            RefPtr<RegisterID> reg = addVar(ident, false);
+            // Don't lazily create functions that override the name 'arguments'
+            // as this would complicate lazy instantiation of actual arguments.
+            if (!canLazilyCreateFunctions || ident == propertyNames().arguments)
+                emitNewFunction(reg.get(), function);
+            else {
+                emitInitLazyRegister(reg.get());
+                m_lazyFunctions.set(reg->index(), function);
+            }
+        }
+    }
+    m_lastLazyFunction = canLazilyCreateFunctions ? codeBlock->m_numVars : m_firstLazyFunction;
+    for (size_t i = 0; i < varStack.size(); ++i) {
+        const Identifier& ident = *varStack[i].first;
+        if (!functionBody->captures(ident))
+            addVar(ident, varStack[i].second & DeclarationStacks::IsConstant);
+    }
+    
+    if (m_shouldEmitDebugHooks)
+        codeBlock->m_numCapturedVars = codeBlock->m_numVars;
+
+    FunctionParameters& parameters = *functionBody->parameters();
+    size_t parameterCount = parameters.size();
+    int nextParameterIndex = -RegisterFile::CallFrameHeaderSize - parameterCount - 1;
+    m_parameters.grow(1 + parameterCount); // reserve space for "this"
+
+    // Add "this" as a parameter
+    m_thisRegister.setIndex(nextParameterIndex);
+    ++m_codeBlock->m_numParameters;
+    
+    for (size_t i = 0; i < parameterCount; ++i)
+        addParameter(parameters[i], ++nextParameterIndex);
+
+    preserveLastVar();
+
+    if (isConstructor()) {
+        RefPtr<RegisterID> func = newTemporary();
+        RefPtr<RegisterID> funcProto = newTemporary();
+
+        emitOpcode(op_get_callee);
+        instructions().append(func->index());
+        // Load prototype.
+        emitGetById(funcProto.get(), func.get(), globalData()->propertyNames->prototype);
+
+        emitOpcode(op_create_this);
+        instructions().append(m_thisRegister.index());
+        instructions().append(funcProto->index());
+    } else if (functionBody->usesThis() || m_shouldEmitDebugHooks) {
+        if (codeBlock->isStrictMode())
+            emitOpcode(op_convert_this_strict);
+        else
+            emitOpcode(op_convert_this);
+        instructions().append(m_thisRegister.index());
+    }
+}
+
+BytecodeGenerator::BytecodeGenerator(EvalNode* evalNode, const ScopeChain& scopeChain, SymbolTable* symbolTable, EvalCodeBlock* codeBlock)
+    : m_shouldEmitDebugHooks(scopeChain.globalObject()->debugger())
+    , m_shouldEmitProfileHooks(scopeChain.globalObject()->supportsProfiling())
+    , m_shouldEmitRichSourceInfo(scopeChain.globalObject()->supportsRichSourceInfo())
+    , m_scopeChain(&scopeChain)
+    , m_symbolTable(symbolTable)
+    , m_scopeNode(evalNode)
+    , m_codeBlock(codeBlock)
+    , m_thisRegister(RegisterFile::ProgramCodeThisRegister)
+    , m_finallyDepth(0)
+    , m_dynamicScopeDepth(0)
+    , m_baseScopeDepth(codeBlock->baseScopeDepth())
+    , m_codeType(EvalCode)
+    , m_nextConstantOffset(0)
+    , m_globalConstantIndex(0)
+    , m_hasCreatedActivation(true)
+    , m_firstLazyFunction(0)
+    , m_lastLazyFunction(0)
+    , m_globalData(&scopeChain.globalObject()->globalData())
+    , m_lastOpcodeID(op_end)
+#ifndef NDEBUG
+    , m_lastOpcodePosition(0)
+#endif
+    , m_stack(m_globalData->stack())
+    , m_usesExceptions(false)
+    , m_regeneratingForExceptionInfo(false)
+    , m_codeBlockBeingRegeneratedFrom(0)
+{
+    if (m_shouldEmitDebugHooks || m_baseScopeDepth)
+        m_codeBlock->setNeedsFullScopeChain(true);
+
+    emitOpcode(op_enter);
+    codeBlock->setGlobalData(m_globalData);
+    m_codeBlock->m_numParameters = 1; // Allocate space for "this"
+
+    const DeclarationStacks::FunctionStack& functionStack = evalNode->functionStack();
+    for (size_t i = 0; i < functionStack.size(); ++i)
+        m_codeBlock->addFunctionDecl(makeFunction(m_globalData, functionStack[i]));
+
+    const DeclarationStacks::VarStack& varStack = evalNode->varStack();
+    unsigned numVariables = varStack.size();
+    Vector<Identifier> variables;
+    variables.reserveCapacity(numVariables);
+    for (size_t i = 0; i < numVariables; ++i)
+        variables.append(*varStack[i].first);
+    codeBlock->adoptVariables(variables);
+    codeBlock->m_numCapturedVars = codeBlock->m_numVars;
+    preserveLastVar();
+}
+
+RegisterID* BytecodeGenerator::emitInitLazyRegister(RegisterID* reg)
+{
+    emitOpcode(op_init_lazy_reg);
+    instructions().append(reg->index());
+    return reg;
+}
+
+void BytecodeGenerator::addParameter(const Identifier& ident, int parameterIndex)
+{
+    // Parameters overwrite var declarations, but not function declarations.
+    StringImpl* rep = ident.impl();
+    if (!m_functions.contains(rep)) {
+        symbolTable().set(rep, parameterIndex);
+        RegisterID& parameter = registerFor(parameterIndex);
+        parameter.setIndex(parameterIndex);
+    }
+
+    // To maintain the calling convention, we have to allocate unique space for
+    // each parameter, even if the parameter doesn't make it into the symbol table.
+    ++m_codeBlock->m_numParameters;
+}
+
+RegisterID* BytecodeGenerator::registerFor(const Identifier& ident)
+{
+    if (ident == propertyNames().thisIdentifier)
+        return &m_thisRegister;
+
+    if (!shouldOptimizeLocals())
+        return 0;
+
+    SymbolTableEntry entry = symbolTable().get(ident.impl());
+    if (entry.isNull())
+        return 0;
+
+    if (ident == propertyNames().arguments)
+        createArgumentsIfNecessary();
+
+    return createLazyRegisterIfNecessary(&registerFor(entry.getIndex()));
+}
+
+bool BytecodeGenerator::willResolveToArguments(const Identifier& ident)
+{
+    if (ident != propertyNames().arguments)
+        return false;
+    
+    if (!shouldOptimizeLocals())
+        return false;
+    
+    SymbolTableEntry entry = symbolTable().get(ident.impl());
+    if (entry.isNull())
+        return false;
+    
+    if (m_codeBlock->usesArguments() && m_codeType == FunctionCode)
+        return true;
+    
+    return false;
+}
+
+RegisterID* BytecodeGenerator::uncheckedRegisterForArguments()
+{
+    ASSERT(willResolveToArguments(propertyNames().arguments));
+
+    SymbolTableEntry entry = symbolTable().get(propertyNames().arguments.impl());
+    ASSERT(!entry.isNull());
+    return &registerFor(entry.getIndex());
+}
+
+RegisterID* BytecodeGenerator::createLazyRegisterIfNecessary(RegisterID* reg)
+{
+    if (m_lastLazyFunction <= reg->index() || reg->index() < m_firstLazyFunction)
+        return reg;
+    emitLazyNewFunction(reg, m_lazyFunctions.get(reg->index()));
+    return reg;
+}
+
+RegisterID* BytecodeGenerator::constRegisterFor(const Identifier& ident)
+{
+    if (m_codeType == EvalCode)
+        return 0;
+
+    SymbolTableEntry entry = symbolTable().get(ident.impl());
+    if (entry.isNull())
+        return 0;
+
+    return createLazyRegisterIfNecessary(&registerFor(entry.getIndex()));
+}
+
+bool BytecodeGenerator::isLocal(const Identifier& ident)
+{
+    if (ident == propertyNames().thisIdentifier)
+        return true;
+    
+    return shouldOptimizeLocals() && symbolTable().contains(ident.impl());
+}
+
+bool BytecodeGenerator::isLocalConstant(const Identifier& ident)
+{
+    return symbolTable().get(ident.impl()).isReadOnly();
+}
+
+RegisterID* BytecodeGenerator::newRegister()
+{
+    m_calleeRegisters.append(m_calleeRegisters.size());
+    m_codeBlock->m_numCalleeRegisters = max<int>(m_codeBlock->m_numCalleeRegisters, m_calleeRegisters.size());
+    return &m_calleeRegisters.last();
+}
+
+RegisterID* BytecodeGenerator::newTemporary()
+{
+    // Reclaim free register IDs.
+    while (m_calleeRegisters.size() && !m_calleeRegisters.last().refCount())
+        m_calleeRegisters.removeLast();
+        
+    RegisterID* result = newRegister();
+    result->setTemporary();
+    return result;
+}
+
+RegisterID* BytecodeGenerator::highestUsedRegister()
+{
+    size_t count = m_codeBlock->m_numCalleeRegisters;
+    while (m_calleeRegisters.size() < count)
+        newRegister();
+    return &m_calleeRegisters.last();
+}
+
+PassRefPtr<LabelScope> BytecodeGenerator::newLabelScope(LabelScope::Type type, const Identifier* name)
+{
+    // Reclaim free label scopes.
+    while (m_labelScopes.size() && !m_labelScopes.last().refCount())
+        m_labelScopes.removeLast();
+
+    // Allocate new label scope.
+    LabelScope scope(type, name, scopeDepth(), newLabel(), type == LabelScope::Loop ? newLabel() : PassRefPtr<Label>()); // Only loops have continue targets.
+    m_labelScopes.append(scope);
+    return &m_labelScopes.last();
+}
+
+PassRefPtr<Label> BytecodeGenerator::newLabel()
+{
+    // Reclaim free label IDs.
+    while (m_labels.size() && !m_labels.last().refCount())
+        m_labels.removeLast();
+
+    // Allocate new label ID.
+    m_labels.append(m_codeBlock);
+    return &m_labels.last();
+}
+
+PassRefPtr<Label> BytecodeGenerator::emitLabel(Label* l0)
+{
+    unsigned newLabelIndex = instructions().size();
+    l0->setLocation(newLabelIndex);
+
+    if (m_codeBlock->numberOfJumpTargets()) {
+        unsigned lastLabelIndex = m_codeBlock->lastJumpTarget();
+        ASSERT(lastLabelIndex <= newLabelIndex);
+        if (newLabelIndex == lastLabelIndex) {
+            // Peephole optimizations have already been disabled by emitting the last label
+            return l0;
+        }
+    }
+
+    m_codeBlock->addJumpTarget(newLabelIndex);
+
+    // This disables peephole optimizations when an instruction is a jump target
+    m_lastOpcodeID = op_end;
+    return l0;
+}
+
+void BytecodeGenerator::emitOpcode(OpcodeID opcodeID)
+{
+#ifndef NDEBUG
+    size_t opcodePosition = instructions().size();
+    ASSERT(opcodePosition - m_lastOpcodePosition == opcodeLength(m_lastOpcodeID) || m_lastOpcodeID == op_end);
+    m_lastOpcodePosition = opcodePosition;
+#endif
+    instructions().append(globalData()->interpreter->getOpcode(opcodeID));
+    m_lastOpcodeID = opcodeID;
+}
+
+void BytecodeGenerator::retrieveLastBinaryOp(int& dstIndex, int& src1Index, int& src2Index)
+{
+    ASSERT(instructions().size() >= 4);
+    size_t size = instructions().size();
+    dstIndex = instructions().at(size - 3).u.operand;
+    src1Index = instructions().at(size - 2).u.operand;
+    src2Index = instructions().at(size - 1).u.operand;
+}
+
+void BytecodeGenerator::retrieveLastUnaryOp(int& dstIndex, int& srcIndex)
+{
+    ASSERT(instructions().size() >= 3);
+    size_t size = instructions().size();
+    dstIndex = instructions().at(size - 2).u.operand;
+    srcIndex = instructions().at(size - 1).u.operand;
+}
+
+void ALWAYS_INLINE BytecodeGenerator::rewindBinaryOp()
+{
+    ASSERT(instructions().size() >= 4);
+    instructions().shrink(instructions().size() - 4);
+    m_lastOpcodeID = op_end;
+}
+
+void ALWAYS_INLINE BytecodeGenerator::rewindUnaryOp()
+{
+    ASSERT(instructions().size() >= 3);
+    instructions().shrink(instructions().size() - 3);
+    m_lastOpcodeID = op_end;
+}
+
+PassRefPtr<Label> BytecodeGenerator::emitJump(Label* target)
+{
+    size_t begin = instructions().size();
+    emitOpcode(target->isForward() ? op_jmp : op_loop);
+    instructions().append(target->bind(begin, instructions().size()));
+    return target;
+}
+
+PassRefPtr<Label> BytecodeGenerator::emitJumpIfTrue(RegisterID* cond, Label* target)
+{
+    if (m_lastOpcodeID == op_less) {
+        int dstIndex;
+        int src1Index;
+        int src2Index;
+
+        retrieveLastBinaryOp(dstIndex, src1Index, src2Index);
+
+        if (cond->index() == dstIndex && cond->isTemporary() && !cond->refCount()) {
+            rewindBinaryOp();
+
+            size_t begin = instructions().size();
+            emitOpcode(target->isForward() ? op_jless : op_loop_if_less);
+            instructions().append(src1Index);
+            instructions().append(src2Index);
+            instructions().append(target->bind(begin, instructions().size()));
+            return target;
+        }
+    } else if (m_lastOpcodeID == op_lesseq) {
+        int dstIndex;
+        int src1Index;
+        int src2Index;
+
+        retrieveLastBinaryOp(dstIndex, src1Index, src2Index);
+
+        if (cond->index() == dstIndex && cond->isTemporary() && !cond->refCount()) {
+            rewindBinaryOp();
+
+            size_t begin = instructions().size();
+            emitOpcode(target->isForward() ? op_jlesseq : op_loop_if_lesseq);
+            instructions().append(src1Index);
+            instructions().append(src2Index);
+            instructions().append(target->bind(begin, instructions().size()));
+            return target;
+        }
+    } else if (m_lastOpcodeID == op_eq_null && target->isForward()) {
+        int dstIndex;
+        int srcIndex;
+
+        retrieveLastUnaryOp(dstIndex, srcIndex);
+
+        if (cond->index() == dstIndex && cond->isTemporary() && !cond->refCount()) {
+            rewindUnaryOp();
+
+            size_t begin = instructions().size();
+            emitOpcode(op_jeq_null);
+            instructions().append(srcIndex);
+            instructions().append(target->bind(begin, instructions().size()));
+            return target;
+        }
+    } else if (m_lastOpcodeID == op_neq_null && target->isForward()) {
+        int dstIndex;
+        int srcIndex;
+
+        retrieveLastUnaryOp(dstIndex, srcIndex);
+
+        if (cond->index() == dstIndex && cond->isTemporary() && !cond->refCount()) {
+            rewindUnaryOp();
+
+            size_t begin = instructions().size();
+            emitOpcode(op_jneq_null);
+            instructions().append(srcIndex);
+            instructions().append(target->bind(begin, instructions().size()));
+            return target;
+        }
+    }
+
+    size_t begin = instructions().size();
+
+    emitOpcode(target->isForward() ? op_jtrue : op_loop_if_true);
+    instructions().append(cond->index());
+    instructions().append(target->bind(begin, instructions().size()));
+    return target;
+}
+
+PassRefPtr<Label> BytecodeGenerator::emitJumpIfFalse(RegisterID* cond, Label* target)
+{
+    if (m_lastOpcodeID == op_less && target->isForward()) {
+        int dstIndex;
+        int src1Index;
+        int src2Index;
+
+        retrieveLastBinaryOp(dstIndex, src1Index, src2Index);
+
+        if (cond->index() == dstIndex && cond->isTemporary() && !cond->refCount()) {
+            rewindBinaryOp();
+
+            size_t begin = instructions().size();
+            emitOpcode(op_jnless);
+            instructions().append(src1Index);
+            instructions().append(src2Index);
+            instructions().append(target->bind(begin, instructions().size()));
+            return target;
+        }
+    } else if (m_lastOpcodeID == op_lesseq && target->isForward()) {
+        int dstIndex;
+        int src1Index;
+        int src2Index;
+
+        retrieveLastBinaryOp(dstIndex, src1Index, src2Index);
+
+        if (cond->index() == dstIndex && cond->isTemporary() && !cond->refCount()) {
+            rewindBinaryOp();
+
+            size_t begin = instructions().size();
+            emitOpcode(op_jnlesseq);
+            instructions().append(src1Index);
+            instructions().append(src2Index);
+            instructions().append(target->bind(begin, instructions().size()));
+            return target;
+        }
+    } else if (m_lastOpcodeID == op_not) {
+        int dstIndex;
+        int srcIndex;
+
+        retrieveLastUnaryOp(dstIndex, srcIndex);
+
+        if (cond->index() == dstIndex && cond->isTemporary() && !cond->refCount()) {
+            rewindUnaryOp();
+
+            size_t begin = instructions().size();
+            emitOpcode(target->isForward() ? op_jtrue : op_loop_if_true);
+            instructions().append(srcIndex);
+            instructions().append(target->bind(begin, instructions().size()));
+            return target;
+        }
+    } else if (m_lastOpcodeID == op_eq_null && target->isForward()) {
+        int dstIndex;
+        int srcIndex;
+
+        retrieveLastUnaryOp(dstIndex, srcIndex);
+
+        if (cond->index() == dstIndex && cond->isTemporary() && !cond->refCount()) {
+            rewindUnaryOp();
+
+            size_t begin = instructions().size();
+            emitOpcode(op_jneq_null);
+            instructions().append(srcIndex);
+            instructions().append(target->bind(begin, instructions().size()));
+            return target;
+        }
+    } else if (m_lastOpcodeID == op_neq_null && target->isForward()) {
+        int dstIndex;
+        int srcIndex;
+
+        retrieveLastUnaryOp(dstIndex, srcIndex);
+
+        if (cond->index() == dstIndex && cond->isTemporary() && !cond->refCount()) {
+            rewindUnaryOp();
+
+            size_t begin = instructions().size();
+            emitOpcode(op_jeq_null);
+            instructions().append(srcIndex);
+            instructions().append(target->bind(begin, instructions().size()));
+            return target;
+        }
+    }
+
+    size_t begin = instructions().size();
+    emitOpcode(target->isForward() ? op_jfalse : op_loop_if_false);
+    instructions().append(cond->index());
+    instructions().append(target->bind(begin, instructions().size()));
+    return target;
+}
+
+PassRefPtr<Label> BytecodeGenerator::emitJumpIfNotFunctionCall(RegisterID* cond, Label* target)
+{
+    size_t begin = instructions().size();
+
+    emitOpcode(op_jneq_ptr);
+    instructions().append(cond->index());
+    instructions().append(m_scopeChain->globalObject()->d()->callFunction);
+    instructions().append(target->bind(begin, instructions().size()));
+    return target;
+}
+
+PassRefPtr<Label> BytecodeGenerator::emitJumpIfNotFunctionApply(RegisterID* cond, Label* target)
+{
+    size_t begin = instructions().size();
+
+    emitOpcode(op_jneq_ptr);
+    instructions().append(cond->index());
+    instructions().append(m_scopeChain->globalObject()->d()->applyFunction);
+    instructions().append(target->bind(begin, instructions().size()));
+    return target;
+}
+
+unsigned BytecodeGenerator::addConstant(const Identifier& ident)
+{
+    StringImpl* rep = ident.impl();
+    pair<IdentifierMap::iterator, bool> result = m_identifierMap.add(rep, m_codeBlock->numberOfIdentifiers());
+    if (result.second) // new entry
+        m_codeBlock->addIdentifier(Identifier(m_globalData, rep));
+
+    return result.first->second;
+}
+
+RegisterID* BytecodeGenerator::addConstantValue(JSValue v)
+{
+    int index = m_nextConstantOffset;
+
+    pair<JSValueMap::iterator, bool> result = m_jsValueMap.add(JSValue::encode(v), m_nextConstantOffset);
+    if (result.second) {
+        m_constantPoolRegisters.append(FirstConstantRegisterIndex + m_nextConstantOffset);
+        ++m_nextConstantOffset;
+        m_codeBlock->addConstantRegister(JSValue(v));
+    } else
+        index = result.first->second;
+
+    return &m_constantPoolRegisters[index];
+}
+
+unsigned BytecodeGenerator::addRegExp(RegExp* r)
+{
+    return m_codeBlock->addRegExp(r);
+}
+
+RegisterID* BytecodeGenerator::emitMove(RegisterID* dst, RegisterID* src)
+{
+    emitOpcode(op_mov);
+    instructions().append(dst->index());
+    instructions().append(src->index());
+    return dst;
+}
+
+RegisterID* BytecodeGenerator::emitUnaryOp(OpcodeID opcodeID, RegisterID* dst, RegisterID* src)
+{
+    emitOpcode(opcodeID);
+    instructions().append(dst->index());
+    instructions().append(src->index());
+    return dst;
+}
+
+RegisterID* BytecodeGenerator::emitPreInc(RegisterID* srcDst)
+{
+    emitOpcode(op_pre_inc);
+    instructions().append(srcDst->index());
+    return srcDst;
+}
+
+RegisterID* BytecodeGenerator::emitPreDec(RegisterID* srcDst)
+{
+    emitOpcode(op_pre_dec);
+    instructions().append(srcDst->index());
+    return srcDst;
+}
+
+RegisterID* BytecodeGenerator::emitPostInc(RegisterID* dst, RegisterID* srcDst)
+{
+    emitOpcode(op_post_inc);
+    instructions().append(dst->index());
+    instructions().append(srcDst->index());
+    return dst;
+}
+
+RegisterID* BytecodeGenerator::emitPostDec(RegisterID* dst, RegisterID* srcDst)
+{
+    emitOpcode(op_post_dec);
+    instructions().append(dst->index());
+    instructions().append(srcDst->index());
+    return dst;
+}
+
+RegisterID* BytecodeGenerator::emitBinaryOp(OpcodeID opcodeID, RegisterID* dst, RegisterID* src1, RegisterID* src2, OperandTypes types)
+{
+    emitOpcode(opcodeID);
+    instructions().append(dst->index());
+    instructions().append(src1->index());
+    instructions().append(src2->index());
+
+    if (opcodeID == op_bitor || opcodeID == op_bitand || opcodeID == op_bitxor ||
+        opcodeID == op_add || opcodeID == op_mul || opcodeID == op_sub || opcodeID == op_div)
+        instructions().append(types.toInt());
+
+    return dst;
+}
+
+RegisterID* BytecodeGenerator::emitEqualityOp(OpcodeID opcodeID, RegisterID* dst, RegisterID* src1, RegisterID* src2)
+{
+    if (m_lastOpcodeID == op_typeof) {
+        int dstIndex;
+        int srcIndex;
+
+        retrieveLastUnaryOp(dstIndex, srcIndex);
+
+        if (src1->index() == dstIndex
+            && src1->isTemporary()
+            && m_codeBlock->isConstantRegisterIndex(src2->index())
+            && m_codeBlock->constantRegister(src2->index()).jsValue().isString()) {
+            const UString& value = asString(m_codeBlock->constantRegister(src2->index()).jsValue())->tryGetValue();
+            if (value == "undefined") {
+                rewindUnaryOp();
+                emitOpcode(op_is_undefined);
+                instructions().append(dst->index());
+                instructions().append(srcIndex);
+                return dst;
+            }
+            if (value == "boolean") {
+                rewindUnaryOp();
+                emitOpcode(op_is_boolean);
+                instructions().append(dst->index());
+                instructions().append(srcIndex);
+                return dst;
+            }
+            if (value == "number") {
+                rewindUnaryOp();
+                emitOpcode(op_is_number);
+                instructions().append(dst->index());
+                instructions().append(srcIndex);
+                return dst;
+            }
+            if (value == "string") {
+                rewindUnaryOp();
+                emitOpcode(op_is_string);
+                instructions().append(dst->index());
+                instructions().append(srcIndex);
+                return dst;
+            }
+            if (value == "object") {
+                rewindUnaryOp();
+                emitOpcode(op_is_object);
+                instructions().append(dst->index());
+                instructions().append(srcIndex);
+                return dst;
+            }
+            if (value == "function") {
+                rewindUnaryOp();
+                emitOpcode(op_is_function);
+                instructions().append(dst->index());
+                instructions().append(srcIndex);
+                return dst;
+            }
+        }
+    }
+
+    emitOpcode(opcodeID);
+    instructions().append(dst->index());
+    instructions().append(src1->index());
+    instructions().append(src2->index());
+    return dst;
+}
+
+RegisterID* BytecodeGenerator::emitLoad(RegisterID* dst, bool b)
+{
+    return emitLoad(dst, jsBoolean(b));
+}
+
+RegisterID* BytecodeGenerator::emitLoad(RegisterID* dst, double number)
+{
+    // FIXME: Our hash tables won't hold infinity, so we make a new JSNumberCell each time.
+    // Later we can do the extra work to handle that like the other cases.
+    if (number == HashTraits<double>::emptyValue() || HashTraits<double>::isDeletedValue(number))
+        return emitLoad(dst, jsNumber(number));
+    JSValue& valueInMap = m_numberMap.add(number, JSValue()).first->second;
+    if (!valueInMap)
+        valueInMap = jsNumber(number);
+    return emitLoad(dst, valueInMap);
+}
+
+RegisterID* BytecodeGenerator::emitLoad(RegisterID* dst, const Identifier& identifier)
+{
+    JSString*& stringInMap = m_stringMap.add(identifier.impl(), 0).first->second;
+    if (!stringInMap)
+        stringInMap = jsOwnedString(globalData(), identifier.ustring());
+    return emitLoad(dst, JSValue(stringInMap));
+}
+
+RegisterID* BytecodeGenerator::emitLoad(RegisterID* dst, JSValue v)
+{
+    RegisterID* constantID = addConstantValue(v);
+    if (dst)
+        return emitMove(dst, constantID);
+    return constantID;
+}
+
+bool BytecodeGenerator::findScopedProperty(const Identifier& property, int& index, size_t& stackDepth, bool forWriting, bool& requiresDynamicChecks, JSObject*& globalObject)
+{
+    // Cases where we cannot statically optimize the lookup.
+    if (property == propertyNames().arguments || !canOptimizeNonLocals()) {
+        stackDepth = 0;
+        index = missingSymbolMarker();
+
+        if (shouldOptimizeLocals() && m_codeType == GlobalCode) {
+            ScopeChainIterator iter = m_scopeChain->begin();
+            globalObject = *iter;
+            ASSERT((++iter) == m_scopeChain->end());
+        }
+        return false;
+    }
+
+    size_t depth = 0;
+    requiresDynamicChecks = false;
+    ScopeChainIterator iter = m_scopeChain->begin();
+    ScopeChainIterator end = m_scopeChain->end();
+    for (; iter != end; ++iter, ++depth) {
+        JSObject* currentScope = *iter;
+        if (!currentScope->isVariableObject())
+            break;
+        JSVariableObject* currentVariableObject = static_cast<JSVariableObject*>(currentScope);
+        SymbolTableEntry entry = currentVariableObject->symbolTable().get(property.impl());
+
+        // Found the property
+        if (!entry.isNull()) {
+            if (entry.isReadOnly() && forWriting) {
+                stackDepth = 0;
+                index = missingSymbolMarker();
+                if (++iter == end)
+                    globalObject = currentVariableObject;
+                return false;
+            }
+            stackDepth = depth + m_codeBlock->needsFullScopeChain();
+            index = entry.getIndex();
+            if (++iter == end)
+                globalObject = currentVariableObject;
+            return true;
+        }
+        bool scopeRequiresDynamicChecks = false;
+        if (currentVariableObject->isDynamicScope(scopeRequiresDynamicChecks))
+            break;
+        requiresDynamicChecks |= scopeRequiresDynamicChecks;
+    }
+    // Can't locate the property but we're able to avoid a few lookups.
+    stackDepth = depth + m_codeBlock->needsFullScopeChain();
+    index = missingSymbolMarker();
+    JSObject* scope = *iter;
+    if (++iter == end)
+        globalObject = scope;
+    return true;
+}
+
+void BytecodeGenerator::emitCheckHasInstance(RegisterID* base)
+{ 
+    emitOpcode(op_check_has_instance);
+    instructions().append(base->index());
+}
+
+RegisterID* BytecodeGenerator::emitInstanceOf(RegisterID* dst, RegisterID* value, RegisterID* base, RegisterID* basePrototype)
+{ 
+    emitOpcode(op_instanceof);
+    instructions().append(dst->index());
+    instructions().append(value->index());
+    instructions().append(base->index());
+    instructions().append(basePrototype->index());
+    return dst;
+}
+
+RegisterID* BytecodeGenerator::emitResolve(RegisterID* dst, const Identifier& property)
+{
+    size_t depth = 0;
+    int index = 0;
+    JSObject* globalObject = 0;
+    bool requiresDynamicChecks = false;
+    if (!findScopedProperty(property, index, depth, false, requiresDynamicChecks, globalObject) && !globalObject) {
+        // We can't optimise at all :-(
+        emitOpcode(op_resolve);
+        instructions().append(dst->index());
+        instructions().append(addConstant(property));
+        return dst;
+    }
+
+    if (globalObject) {
+        bool forceGlobalResolve = false;
+        if (m_regeneratingForExceptionInfo) {
+#if ENABLE(JIT)
+            forceGlobalResolve = m_codeBlockBeingRegeneratedFrom->hasGlobalResolveInfoAtBytecodeOffset(instructions().size());
+#else
+            forceGlobalResolve = m_codeBlockBeingRegeneratedFrom->hasGlobalResolveInstructionAtBytecodeOffset(instructions().size());
+#endif
+        }
+
+        if (index != missingSymbolMarker() && !forceGlobalResolve && !requiresDynamicChecks) {
+            // Directly index the property lookup across multiple scopes.
+            return emitGetScopedVar(dst, depth, index, globalObject);
+        }
+
+#if ENABLE(JIT)
+        m_codeBlock->addGlobalResolveInfo(instructions().size());
+#else
+        m_codeBlock->addGlobalResolveInstruction(instructions().size());
+#endif
+        emitOpcode(requiresDynamicChecks ? op_resolve_global_dynamic : op_resolve_global);
+        instructions().append(dst->index());
+        instructions().append(addConstant(property));
+        instructions().append(0);
+        instructions().append(0);
+        if (requiresDynamicChecks)
+            instructions().append(depth);
+        return dst;
+    }
+
+    if (requiresDynamicChecks) {
+        // If we get here we have eval nested inside a |with| just give up
+        emitOpcode(op_resolve);
+        instructions().append(dst->index());
+        instructions().append(addConstant(property));
+        return dst;
+    }
+
+    if (index != missingSymbolMarker()) {
+        // Directly index the property lookup across multiple scopes.
+        return emitGetScopedVar(dst, depth, index, globalObject);
+    }
+
+    // In this case we are at least able to drop a few scope chains from the
+    // lookup chain, although we still need to hash from then on.
+    emitOpcode(op_resolve_skip);
+    instructions().append(dst->index());
+    instructions().append(addConstant(property));
+    instructions().append(depth);
+    return dst;
+}
+
+RegisterID* BytecodeGenerator::emitGetScopedVar(RegisterID* dst, size_t depth, int index, JSValue globalObject)
+{
+    if (globalObject) {
+        emitOpcode(op_get_global_var);
+        instructions().append(dst->index());
+        instructions().append(index);
+        return dst;
+    }
+
+    emitOpcode(op_get_scoped_var);
+    instructions().append(dst->index());
+    instructions().append(index);
+    instructions().append(depth);
+    return dst;
+}
+
+RegisterID* BytecodeGenerator::emitPutScopedVar(size_t depth, int index, RegisterID* value, JSValue globalObject)
+{
+    if (globalObject) {
+        emitOpcode(op_put_global_var);
+        instructions().append(index);
+        instructions().append(value->index());
+        return value;
+    }
+    emitOpcode(op_put_scoped_var);
+    instructions().append(index);
+    instructions().append(depth);
+    instructions().append(value->index());
+    return value;
+}
+
+RegisterID* BytecodeGenerator::emitResolveBase(RegisterID* dst, const Identifier& property)
+{
+    size_t depth = 0;
+    int index = 0;
+    JSObject* globalObject = 0;
+    bool requiresDynamicChecks = false;
+    findScopedProperty(property, index, depth, false, requiresDynamicChecks, globalObject);
+    if (!globalObject || requiresDynamicChecks) {
+        // We can't optimise at all :-(
+        emitOpcode(op_resolve_base);
+        instructions().append(dst->index());
+        instructions().append(addConstant(property));
+        instructions().append(false);
+        return dst;
+    }
+
+    // Global object is the base
+    return emitLoad(dst, JSValue(globalObject));
+}
+
+RegisterID* BytecodeGenerator::emitResolveBaseForPut(RegisterID* dst, const Identifier& property)
+{
+    if (!m_codeBlock->isStrictMode())
+        return emitResolveBase(dst, property);
+    size_t depth = 0;
+    int index = 0;
+    JSObject* globalObject = 0;
+    bool requiresDynamicChecks = false;
+    findScopedProperty(property, index, depth, false, requiresDynamicChecks, globalObject);
+    if (!globalObject || requiresDynamicChecks) {
+        // We can't optimise at all :-(
+        emitOpcode(op_resolve_base);
+        instructions().append(dst->index());
+        instructions().append(addConstant(property));
+        instructions().append(true);
+        return dst;
+    }
+    
+    // Global object is the base
+    RefPtr<RegisterID> result = emitLoad(dst, JSValue(globalObject));
+    emitOpcode(op_ensure_property_exists);
+    instructions().append(dst->index());
+    instructions().append(addConstant(property));
+    return result.get();
+}
+
+RegisterID* BytecodeGenerator::emitResolveWithBase(RegisterID* baseDst, RegisterID* propDst, const Identifier& property)
+{
+    size_t depth = 0;
+    int index = 0;
+    JSObject* globalObject = 0;
+    bool requiresDynamicChecks = false;
+    if (!findScopedProperty(property, index, depth, false, requiresDynamicChecks, globalObject) || !globalObject || requiresDynamicChecks) {
+        // We can't optimise at all :-(
+        emitOpcode(op_resolve_with_base);
+        instructions().append(baseDst->index());
+        instructions().append(propDst->index());
+        instructions().append(addConstant(property));
+        return baseDst;
+    }
+
+    bool forceGlobalResolve = false;
+    if (m_regeneratingForExceptionInfo) {
+#if ENABLE(JIT)
+        forceGlobalResolve = m_codeBlockBeingRegeneratedFrom->hasGlobalResolveInfoAtBytecodeOffset(instructions().size());
+#else
+        forceGlobalResolve = m_codeBlockBeingRegeneratedFrom->hasGlobalResolveInstructionAtBytecodeOffset(instructions().size());
+#endif
+    }
+
+    // Global object is the base
+    emitLoad(baseDst, JSValue(globalObject));
+
+    if (index != missingSymbolMarker() && !forceGlobalResolve) {
+        // Directly index the property lookup across multiple scopes.
+        emitGetScopedVar(propDst, depth, index, globalObject);
+        return baseDst;
+    }
+
+#if ENABLE(JIT)
+    m_codeBlock->addGlobalResolveInfo(instructions().size());
+#else
+    m_codeBlock->addGlobalResolveInstruction(instructions().size());
+#endif
+    emitOpcode(requiresDynamicChecks ? op_resolve_global_dynamic : op_resolve_global);
+    instructions().append(propDst->index());
+    instructions().append(addConstant(property));
+    instructions().append(0);
+    instructions().append(0);
+    if (requiresDynamicChecks)
+        instructions().append(depth);
+    return baseDst;
+}
+
+void BytecodeGenerator::emitMethodCheck()
+{
+    emitOpcode(op_method_check);
+}
+
+RegisterID* BytecodeGenerator::emitGetById(RegisterID* dst, RegisterID* base, const Identifier& property)
+{
+#if ENABLE(JIT)
+    m_codeBlock->addStructureStubInfo(StructureStubInfo(access_get_by_id));
+#else
+    m_codeBlock->addPropertyAccessInstruction(instructions().size());
+#endif
+
+    emitOpcode(op_get_by_id);
+    instructions().append(dst->index());
+    instructions().append(base->index());
+    instructions().append(addConstant(property));
+    instructions().append(0);
+    instructions().append(0);
+    instructions().append(0);
+    instructions().append(0);
+    return dst;
+}
+
+RegisterID* BytecodeGenerator::emitGetArgumentsLength(RegisterID* dst, RegisterID* base)
+{
+    emitOpcode(op_get_arguments_length);
+    instructions().append(dst->index());
+    ASSERT(base->index() == m_codeBlock->argumentsRegister());
+    instructions().append(base->index());
+    instructions().append(addConstant(propertyNames().length));
+    return dst;
+}
+
+RegisterID* BytecodeGenerator::emitPutById(RegisterID* base, const Identifier& property, RegisterID* value)
+{
+#if ENABLE(JIT)
+    m_codeBlock->addStructureStubInfo(StructureStubInfo(access_put_by_id));
+#else
+    m_codeBlock->addPropertyAccessInstruction(instructions().size());
+#endif
+
+    emitOpcode(op_put_by_id);
+    instructions().append(base->index());
+    instructions().append(addConstant(property));
+    instructions().append(value->index());
+    instructions().append(0);
+    instructions().append(0);
+    instructions().append(0);
+    instructions().append(0);
+    instructions().append(0);
+    return value;
+}
+
+RegisterID* BytecodeGenerator::emitDirectPutById(RegisterID* base, const Identifier& property, RegisterID* value)
+{
+#if ENABLE(JIT)
+    m_codeBlock->addStructureStubInfo(StructureStubInfo(access_put_by_id));
+#else
+    m_codeBlock->addPropertyAccessInstruction(instructions().size());
+#endif
+    
+    emitOpcode(op_put_by_id);
+    instructions().append(base->index());
+    instructions().append(addConstant(property));
+    instructions().append(value->index());
+    instructions().append(0);
+    instructions().append(0);
+    instructions().append(0);
+    instructions().append(0);
+    instructions().append(property != m_globalData->propertyNames->underscoreProto);
+    return value;
+}
+
+RegisterID* BytecodeGenerator::emitPutGetter(RegisterID* base, const Identifier& property, RegisterID* value)
+{
+    emitOpcode(op_put_getter);
+    instructions().append(base->index());
+    instructions().append(addConstant(property));
+    instructions().append(value->index());
+    return value;
+}
+
+RegisterID* BytecodeGenerator::emitPutSetter(RegisterID* base, const Identifier& property, RegisterID* value)
+{
+    emitOpcode(op_put_setter);
+    instructions().append(base->index());
+    instructions().append(addConstant(property));
+    instructions().append(value->index());
+    return value;
+}
+
+RegisterID* BytecodeGenerator::emitDeleteById(RegisterID* dst, RegisterID* base, const Identifier& property)
+{
+    emitOpcode(op_del_by_id);
+    instructions().append(dst->index());
+    instructions().append(base->index());
+    instructions().append(addConstant(property));
+    return dst;
+}
+
+RegisterID* BytecodeGenerator::emitGetArgumentByVal(RegisterID* dst, RegisterID* base, RegisterID* property)
+{
+    emitOpcode(op_get_argument_by_val);
+    instructions().append(dst->index());
+    ASSERT(base->index() == m_codeBlock->argumentsRegister());
+    instructions().append(base->index());
+    instructions().append(property->index());
+    return dst;
+}
+
+RegisterID* BytecodeGenerator::emitGetByVal(RegisterID* dst, RegisterID* base, RegisterID* property)
+{
+    for (size_t i = m_forInContextStack.size(); i > 0; i--) {
+        ForInContext& context = m_forInContextStack[i - 1];
+        if (context.propertyRegister == property) {
+            emitOpcode(op_get_by_pname);
+            instructions().append(dst->index());
+            instructions().append(base->index());
+            instructions().append(property->index());
+            instructions().append(context.expectedSubscriptRegister->index());
+            instructions().append(context.iterRegister->index());
+            instructions().append(context.indexRegister->index());
+            return dst;
+        }
+    }
+    emitOpcode(op_get_by_val);
+    instructions().append(dst->index());
+    instructions().append(base->index());
+    instructions().append(property->index());
+    return dst;
+}
+
+RegisterID* BytecodeGenerator::emitPutByVal(RegisterID* base, RegisterID* property, RegisterID* value)
+{
+    emitOpcode(op_put_by_val);
+    instructions().append(base->index());
+    instructions().append(property->index());
+    instructions().append(value->index());
+    return value;
+}
+
+RegisterID* BytecodeGenerator::emitDeleteByVal(RegisterID* dst, RegisterID* base, RegisterID* property)
+{
+    emitOpcode(op_del_by_val);
+    instructions().append(dst->index());
+    instructions().append(base->index());
+    instructions().append(property->index());
+    return dst;
+}
+
+RegisterID* BytecodeGenerator::emitPutByIndex(RegisterID* base, unsigned index, RegisterID* value)
+{
+    emitOpcode(op_put_by_index);
+    instructions().append(base->index());
+    instructions().append(index);
+    instructions().append(value->index());
+    return value;
+}
+
+RegisterID* BytecodeGenerator::emitNewObject(RegisterID* dst)
+{
+    emitOpcode(op_new_object);
+    instructions().append(dst->index());
+    return dst;
+}
+
+RegisterID* BytecodeGenerator::emitNewArray(RegisterID* dst, ElementNode* elements)
+{
+    Vector<RefPtr<RegisterID>, 16> argv;
+    for (ElementNode* n = elements; n; n = n->next()) {
+        if (n->elision())
+            break;
+        argv.append(newTemporary());
+        // op_new_array requires the initial values to be a sequential range of registers
+        ASSERT(argv.size() == 1 || argv[argv.size() - 1]->index() == argv[argv.size() - 2]->index() + 1);
+        emitNode(argv.last().get(), n->value());
+    }
+    emitOpcode(op_new_array);
+    instructions().append(dst->index());
+    instructions().append(argv.size() ? argv[0]->index() : 0); // argv
+    instructions().append(argv.size()); // argc
+    return dst;
+}
+
+RegisterID* BytecodeGenerator::emitNewFunction(RegisterID* dst, FunctionBodyNode* function)
+{
+    return emitNewFunctionInternal(dst, m_codeBlock->addFunctionDecl(makeFunction(m_globalData, function)), false);
+}
+
+RegisterID* BytecodeGenerator::emitLazyNewFunction(RegisterID* dst, FunctionBodyNode* function)
+{
+    std::pair<FunctionOffsetMap::iterator, bool> ptr = m_functionOffsets.add(function, 0);
+    if (ptr.second)
+        ptr.first->second = m_codeBlock->addFunctionDecl(makeFunction(m_globalData, function));
+    return emitNewFunctionInternal(dst, ptr.first->second, true);
+}
+
+RegisterID* BytecodeGenerator::emitNewFunctionInternal(RegisterID* dst, unsigned index, bool doNullCheck)
+{
+    createActivationIfNecessary();
+    emitOpcode(op_new_func);
+    instructions().append(dst->index());
+    instructions().append(index);
+    instructions().append(doNullCheck);
+    return dst;
+}
+
+RegisterID* BytecodeGenerator::emitNewRegExp(RegisterID* dst, RegExp* regExp)
+{
+    emitOpcode(op_new_regexp);
+    instructions().append(dst->index());
+    instructions().append(addRegExp(regExp));
+    return dst;
+}
+
+RegisterID* BytecodeGenerator::emitNewFunctionExpression(RegisterID* r0, FuncExprNode* n)
+{
+    FunctionBodyNode* function = n->body();
+    unsigned index = m_codeBlock->addFunctionExpr(makeFunction(m_globalData, function));
+    
+    createActivationIfNecessary();
+    emitOpcode(op_new_func_exp);
+    instructions().append(r0->index());
+    instructions().append(index);
+    return r0;
+}
+
+RegisterID* BytecodeGenerator::emitCall(RegisterID* dst, RegisterID* func, CallArguments& callArguments, unsigned divot, unsigned startOffset, unsigned endOffset)
+{
+    return emitCall(op_call, dst, func, callArguments, divot, startOffset, endOffset);
+}
+
+void BytecodeGenerator::createArgumentsIfNecessary()
+{
+    if (m_codeType != FunctionCode)
+        return;
+    
+    if (!m_codeBlock->usesArguments())
+        return;
+
+    // If we're in strict mode we tear off the arguments on function
+    // entry, so there's no need to check if we need to create them
+    // now
+    if (m_codeBlock->isStrictMode())
+        return;
+
+    emitOpcode(op_create_arguments);
+    instructions().append(m_codeBlock->argumentsRegister());
+}
+
+void BytecodeGenerator::createActivationIfNecessary()
+{
+    if (m_hasCreatedActivation)
+        return;
+    if (!m_codeBlock->needsFullScopeChain())
+        return;
+    emitOpcode(op_create_activation);
+    instructions().append(m_activationRegister->index());
+}
+
+RegisterID* BytecodeGenerator::emitCallEval(RegisterID* dst, RegisterID* func, CallArguments& callArguments, unsigned divot, unsigned startOffset, unsigned endOffset)
+{
+    return emitCall(op_call_eval, dst, func, callArguments, divot, startOffset, endOffset);
+}
+
+RegisterID* BytecodeGenerator::emitCall(OpcodeID opcodeID, RegisterID* dst, RegisterID* func, CallArguments& callArguments, unsigned divot, unsigned startOffset, unsigned endOffset)
+{
+    ASSERT(opcodeID == op_call || opcodeID == op_call_eval);
+    ASSERT(func->refCount());
+
+    if (m_shouldEmitProfileHooks)
+        emitMove(callArguments.profileHookRegister(), func);
+
+    // Generate code for arguments.
+    unsigned argumentIndex = 0;
+    for (ArgumentListNode* n = callArguments.argumentsNode()->m_listNode; n; n = n->m_next)
+        emitNode(callArguments.argumentRegister(argumentIndex++), n);
+
+    // Reserve space for call frame.
+    Vector<RefPtr<RegisterID>, RegisterFile::CallFrameHeaderSize> callFrame;
+    for (int i = 0; i < RegisterFile::CallFrameHeaderSize; ++i)
+        callFrame.append(newTemporary());
+
+    if (m_shouldEmitProfileHooks) {
+        emitOpcode(op_profile_will_call);
+        instructions().append(callArguments.profileHookRegister()->index());
+    }
+
+    emitExpressionInfo(divot, startOffset, endOffset);
+
+#if ENABLE(JIT)
+    m_codeBlock->addCallLinkInfo();
+#endif
+
+    // Emit call.
+    emitOpcode(opcodeID);
+    instructions().append(func->index()); // func
+    instructions().append(callArguments.count()); // argCount
+    instructions().append(callArguments.callFrame()); // registerOffset
+    if (dst != ignoredResult()) {
+        emitOpcode(op_call_put_result);
+        instructions().append(dst->index()); // dst
+    }
+
+    if (m_shouldEmitProfileHooks) {
+        emitOpcode(op_profile_did_call);
+        instructions().append(callArguments.profileHookRegister()->index());
+    }
+
+    return dst;
+}
+
+RegisterID* BytecodeGenerator::emitLoadVarargs(RegisterID* argCountDst, RegisterID* thisRegister, RegisterID* arguments)
+{
+    ASSERT(argCountDst->index() < arguments->index());
+    emitOpcode(op_load_varargs);
+    instructions().append(argCountDst->index());
+    instructions().append(arguments->index());
+    instructions().append(thisRegister->index() + RegisterFile::CallFrameHeaderSize); // initial registerOffset
+    return argCountDst;
+}
+
+RegisterID* BytecodeGenerator::emitCallVarargs(RegisterID* dst, RegisterID* func, RegisterID* thisRegister, RegisterID* argCountRegister, unsigned divot, unsigned startOffset, unsigned endOffset)
+{
+    ASSERT(func->refCount());
+    ASSERT(thisRegister->refCount());
+    ASSERT(dst != func);
+    if (m_shouldEmitProfileHooks) {
+        emitOpcode(op_profile_will_call);
+        instructions().append(func->index());
+    }
+    
+    emitExpressionInfo(divot, startOffset, endOffset);
+    
+    // Emit call.
+    emitOpcode(op_call_varargs);
+    instructions().append(func->index()); // func
+    instructions().append(argCountRegister->index()); // arg count
+    instructions().append(thisRegister->index() + RegisterFile::CallFrameHeaderSize); // initial registerOffset
+    if (dst != ignoredResult()) {
+        emitOpcode(op_call_put_result);
+        instructions().append(dst->index()); // dst
+    }
+    if (m_shouldEmitProfileHooks) {
+        emitOpcode(op_profile_did_call);
+        instructions().append(func->index());
+    }
+    return dst;
+}
+
+RegisterID* BytecodeGenerator::emitReturn(RegisterID* src)
+{
+    if (m_codeBlock->needsFullScopeChain()) {
+        emitOpcode(op_tear_off_activation);
+        instructions().append(m_activationRegister->index());
+        instructions().append(m_codeBlock->argumentsRegister());
+    } else if (m_codeBlock->usesArguments() && m_codeBlock->m_numParameters > 1
+               && !m_codeBlock->isStrictMode()) { // If there are no named parameters, there's nothing to tear off, since extra / unnamed parameters get copied to the arguments object at construct time.
+        emitOpcode(op_tear_off_arguments);
+        instructions().append(m_codeBlock->argumentsRegister());
+    }
+
+    // Constructors use op_ret_object_or_this to check the result is an
+    // object, unless we can trivially determine the check is not
+    // necessary (currently, if the return value is 'this').
+    if (isConstructor() && (src->index() != m_thisRegister.index())) {
+        emitOpcode(op_ret_object_or_this);
+        instructions().append(src->index());
+        instructions().append(m_thisRegister.index());
+        return src;
+    }
+    return emitUnaryNoDstOp(op_ret, src);
+}
+
+RegisterID* BytecodeGenerator::emitUnaryNoDstOp(OpcodeID opcodeID, RegisterID* src)
+{
+    emitOpcode(opcodeID);
+    instructions().append(src->index());
+    return src;
+}
+
+RegisterID* BytecodeGenerator::emitConstruct(RegisterID* dst, RegisterID* func, CallArguments& callArguments, unsigned divot, unsigned startOffset, unsigned endOffset)
+{
+    ASSERT(func->refCount());
+
+    if (m_shouldEmitProfileHooks)
+        emitMove(callArguments.profileHookRegister(), func);
+
+    // Generate code for arguments.
+    unsigned argumentIndex = 0;
+    if (ArgumentsNode* argumentsNode = callArguments.argumentsNode()) {
+        for (ArgumentListNode* n = argumentsNode->m_listNode; n; n = n->m_next)
+            emitNode(callArguments.argumentRegister(argumentIndex++), n);
+    }
+
+    if (m_shouldEmitProfileHooks) {
+        emitOpcode(op_profile_will_call);
+        instructions().append(callArguments.profileHookRegister()->index());
+    }
+
+    // Reserve space for call frame.
+    Vector<RefPtr<RegisterID>, RegisterFile::CallFrameHeaderSize> callFrame;
+    for (int i = 0; i < RegisterFile::CallFrameHeaderSize; ++i)
+        callFrame.append(newTemporary());
+
+    emitExpressionInfo(divot, startOffset, endOffset);
+
+#if ENABLE(JIT)
+    m_codeBlock->addCallLinkInfo();
+#endif
+
+    emitOpcode(op_construct);
+    instructions().append(func->index()); // func
+    instructions().append(callArguments.count()); // argCount
+    instructions().append(callArguments.callFrame()); // registerOffset
+    if (dst != ignoredResult()) {
+        emitOpcode(op_call_put_result);
+        instructions().append(dst->index()); // dst
+    }
+
+    if (m_shouldEmitProfileHooks) {
+        emitOpcode(op_profile_did_call);
+        instructions().append(callArguments.profileHookRegister()->index());
+    }
+
+    return dst;
+}
+
+RegisterID* BytecodeGenerator::emitStrcat(RegisterID* dst, RegisterID* src, int count)
+{
+    emitOpcode(op_strcat);
+    instructions().append(dst->index());
+    instructions().append(src->index());
+    instructions().append(count);
+
+    return dst;
+}
+
+void BytecodeGenerator::emitToPrimitive(RegisterID* dst, RegisterID* src)
+{
+    emitOpcode(op_to_primitive);
+    instructions().append(dst->index());
+    instructions().append(src->index());
+}
+
+RegisterID* BytecodeGenerator::emitPushScope(RegisterID* scope)
+{
+    ASSERT(scope->isTemporary());
+    ControlFlowContext context;
+    context.isFinallyBlock = false;
+    m_scopeContextStack.append(context);
+    m_dynamicScopeDepth++;
+
+    return emitUnaryNoDstOp(op_push_scope, scope);
+}
+
+void BytecodeGenerator::emitPopScope()
+{
+    ASSERT(m_scopeContextStack.size());
+    ASSERT(!m_scopeContextStack.last().isFinallyBlock);
+
+    emitOpcode(op_pop_scope);
+
+    m_scopeContextStack.removeLast();
+    m_dynamicScopeDepth--;
+}
+
+void BytecodeGenerator::emitDebugHook(DebugHookID debugHookID, int firstLine, int lastLine)
+{
+#if ENABLE(DEBUG_WITH_BREAKPOINT)
+    if (debugHookID != DidReachBreakpoint)
+        return;
+#else
+    if (!m_shouldEmitDebugHooks)
+        return;
+#endif
+    emitOpcode(op_debug);
+    instructions().append(debugHookID);
+    instructions().append(firstLine);
+    instructions().append(lastLine);
+}
+
+void BytecodeGenerator::pushFinallyContext(Label* target, RegisterID* retAddrDst)
+{
+    ControlFlowContext scope;
+    scope.isFinallyBlock = true;
+    FinallyContext context = { target, retAddrDst };
+    scope.finallyContext = context;
+    m_scopeContextStack.append(scope);
+    m_finallyDepth++;
+}
+
+void BytecodeGenerator::popFinallyContext()
+{
+    ASSERT(m_scopeContextStack.size());
+    ASSERT(m_scopeContextStack.last().isFinallyBlock);
+    ASSERT(m_finallyDepth > 0);
+    m_scopeContextStack.removeLast();
+    m_finallyDepth--;
+}
+
+LabelScope* BytecodeGenerator::breakTarget(const Identifier& name)
+{
+    // Reclaim free label scopes.
+    //
+    // The condition was previously coded as 'm_labelScopes.size() && !m_labelScopes.last().refCount()',
+    // however sometimes this appears to lead to GCC going a little haywire and entering the loop with
+    // size 0, leading to segfaulty badness.  We are yet to identify a valid cause within our code to
+    // cause the GCC codegen to misbehave in this fashion, and as such the following refactoring of the
+    // loop condition is a workaround.
+    while (m_labelScopes.size()) {
+        if  (m_labelScopes.last().refCount())
+            break;
+        m_labelScopes.removeLast();
+    }
+
+    if (!m_labelScopes.size())
+        return 0;
+
+    // We special-case the following, which is a syntax error in Firefox:
+    // label:
+    //     break;
+    if (name.isEmpty()) {
+        for (int i = m_labelScopes.size() - 1; i >= 0; --i) {
+            LabelScope* scope = &m_labelScopes[i];
+            if (scope->type() != LabelScope::NamedLabel) {
+                ASSERT(scope->breakTarget());
+                return scope;
+            }
+        }
+        return 0;
+    }
+
+    for (int i = m_labelScopes.size() - 1; i >= 0; --i) {
+        LabelScope* scope = &m_labelScopes[i];
+        if (scope->name() && *scope->name() == name) {
+            ASSERT(scope->breakTarget());
+            return scope;
+        }
+    }
+    return 0;
+}
+
+LabelScope* BytecodeGenerator::continueTarget(const Identifier& name)
+{
+    // Reclaim free label scopes.
+    while (m_labelScopes.size() && !m_labelScopes.last().refCount())
+        m_labelScopes.removeLast();
+
+    if (!m_labelScopes.size())
+        return 0;
+
+    if (name.isEmpty()) {
+        for (int i = m_labelScopes.size() - 1; i >= 0; --i) {
+            LabelScope* scope = &m_labelScopes[i];
+            if (scope->type() == LabelScope::Loop) {
+                ASSERT(scope->continueTarget());
+                return scope;
+            }
+        }
+        return 0;
+    }
+
+    // Continue to the loop nested nearest to the label scope that matches
+    // 'name'.
+    LabelScope* result = 0;
+    for (int i = m_labelScopes.size() - 1; i >= 0; --i) {
+        LabelScope* scope = &m_labelScopes[i];
+        if (scope->type() == LabelScope::Loop) {
+            ASSERT(scope->continueTarget());
+            result = scope;
+        }
+        if (scope->name() && *scope->name() == name)
+            return result; // may be 0
+    }
+    return 0;
+}
+
+PassRefPtr<Label> BytecodeGenerator::emitComplexJumpScopes(Label* target, ControlFlowContext* topScope, ControlFlowContext* bottomScope)
+{
+    while (topScope > bottomScope) {
+        // First we count the number of dynamic scopes we need to remove to get
+        // to a finally block.
+        int nNormalScopes = 0;
+        while (topScope > bottomScope) {
+            if (topScope->isFinallyBlock)
+                break;
+            ++nNormalScopes;
+            --topScope;
+        }
+
+        if (nNormalScopes) {
+            size_t begin = instructions().size();
+
+            // We need to remove a number of dynamic scopes to get to the next
+            // finally block
+            emitOpcode(op_jmp_scopes);
+            instructions().append(nNormalScopes);
+
+            // If topScope == bottomScope then there isn't actually a finally block
+            // left to emit, so make the jmp_scopes jump directly to the target label
+            if (topScope == bottomScope) {
+                instructions().append(target->bind(begin, instructions().size()));
+                return target;
+            }
+
+            // Otherwise we just use jmp_scopes to pop a group of scopes and go
+            // to the next instruction
+            RefPtr<Label> nextInsn = newLabel();
+            instructions().append(nextInsn->bind(begin, instructions().size()));
+            emitLabel(nextInsn.get());
+        }
+
+        while (topScope > bottomScope && topScope->isFinallyBlock) {
+            emitJumpSubroutine(topScope->finallyContext.retAddrDst, topScope->finallyContext.finallyAddr);
+            --topScope;
+        }
+    }
+    return emitJump(target);
+}
+
+PassRefPtr<Label> BytecodeGenerator::emitJumpScopes(Label* target, int targetScopeDepth)
+{
+    ASSERT(scopeDepth() - targetScopeDepth >= 0);
+    ASSERT(target->isForward());
+
+    size_t scopeDelta = scopeDepth() - targetScopeDepth;
+    ASSERT(scopeDelta <= m_scopeContextStack.size());
+    if (!scopeDelta)
+        return emitJump(target);
+
+    if (m_finallyDepth)
+        return emitComplexJumpScopes(target, &m_scopeContextStack.last(), &m_scopeContextStack.last() - scopeDelta);
+
+    size_t begin = instructions().size();
+
+    emitOpcode(op_jmp_scopes);
+    instructions().append(scopeDelta);
+    instructions().append(target->bind(begin, instructions().size()));
+    return target;
+}
+
+RegisterID* BytecodeGenerator::emitGetPropertyNames(RegisterID* dst, RegisterID* base, RegisterID* i, RegisterID* size, Label* breakTarget)
+{
+    size_t begin = instructions().size();
+
+    emitOpcode(op_get_pnames);
+    instructions().append(dst->index());
+    instructions().append(base->index());
+    instructions().append(i->index());
+    instructions().append(size->index());
+    instructions().append(breakTarget->bind(begin, instructions().size()));
+    return dst;
+}
+
+RegisterID* BytecodeGenerator::emitNextPropertyName(RegisterID* dst, RegisterID* base, RegisterID* i, RegisterID* size, RegisterID* iter, Label* target)
+{
+    size_t begin = instructions().size();
+
+    emitOpcode(op_next_pname);
+    instructions().append(dst->index());
+    instructions().append(base->index());
+    instructions().append(i->index());
+    instructions().append(size->index());
+    instructions().append(iter->index());
+    instructions().append(target->bind(begin, instructions().size()));
+    return dst;
+}
+
+RegisterID* BytecodeGenerator::emitCatch(RegisterID* targetRegister, Label* start, Label* end)
+{
+    m_usesExceptions = true;
+#if ENABLE(JIT)
+    HandlerInfo info = { start->bind(0, 0), end->bind(0, 0), instructions().size(), m_dynamicScopeDepth + m_baseScopeDepth, CodeLocationLabel() };
+#else
+    HandlerInfo info = { start->bind(0, 0), end->bind(0, 0), instructions().size(), m_dynamicScopeDepth + m_baseScopeDepth };
+#endif
+
+    m_codeBlock->addExceptionHandler(info);
+    emitOpcode(op_catch);
+    instructions().append(targetRegister->index());
+    return targetRegister;
+}
+
+void BytecodeGenerator::emitThrowReferenceError(const UString& message)
+{
+    emitOpcode(op_throw_reference_error);
+    instructions().append(addConstantValue(jsString(globalData(), message))->index());
+}
+
+void BytecodeGenerator::emitThrowSyntaxError(const UString& message)
+{
+    emitOpcode(op_throw_syntax_error);
+    instructions().append(addConstantValue(jsString(globalData(), message))->index());
+}
+
+PassRefPtr<Label> BytecodeGenerator::emitJumpSubroutine(RegisterID* retAddrDst, Label* finally)
+{
+    size_t begin = instructions().size();
+
+    emitOpcode(op_jsr);
+    instructions().append(retAddrDst->index());
+    instructions().append(finally->bind(begin, instructions().size()));
+    emitLabel(newLabel().get()); // Record the fact that the next instruction is implicitly labeled, because op_sret will return to it.
+    return finally;
+}
+
+void BytecodeGenerator::emitSubroutineReturn(RegisterID* retAddrSrc)
+{
+    emitOpcode(op_sret);
+    instructions().append(retAddrSrc->index());
+}
+
+void BytecodeGenerator::emitPushNewScope(RegisterID* dst, const Identifier& property, RegisterID* value)
+{
+    ControlFlowContext context;
+    context.isFinallyBlock = false;
+    m_scopeContextStack.append(context);
+    m_dynamicScopeDepth++;
+
+    emitOpcode(op_push_new_scope);
+    instructions().append(dst->index());
+    instructions().append(addConstant(property));
+    instructions().append(value->index());
+}
+
+void BytecodeGenerator::beginSwitch(RegisterID* scrutineeRegister, SwitchInfo::SwitchType type)
+{
+    SwitchInfo info = { instructions().size(), type };
+    switch (type) {
+        case SwitchInfo::SwitchImmediate:
+            emitOpcode(op_switch_imm);
+            break;
+        case SwitchInfo::SwitchCharacter:
+            emitOpcode(op_switch_char);
+            break;
+        case SwitchInfo::SwitchString:
+            emitOpcode(op_switch_string);
+            break;
+        default:
+            ASSERT_NOT_REACHED();
+    }
+
+    instructions().append(0); // place holder for table index
+    instructions().append(0); // place holder for default target    
+    instructions().append(scrutineeRegister->index());
+    m_switchContextStack.append(info);
+}
+
+static int32_t keyForImmediateSwitch(ExpressionNode* node, int32_t min, int32_t max)
+{
+    UNUSED_PARAM(max);
+    ASSERT(node->isNumber());
+    double value = static_cast<NumberNode*>(node)->value();
+    int32_t key = static_cast<int32_t>(value);
+    ASSERT(key == value);
+    ASSERT(key >= min);
+    ASSERT(key <= max);
+    return key - min;
+}
+
+static void prepareJumpTableForImmediateSwitch(SimpleJumpTable& jumpTable, int32_t switchAddress, uint32_t clauseCount, RefPtr<Label>* labels, ExpressionNode** nodes, int32_t min, int32_t max)
+{
+    jumpTable.min = min;
+    jumpTable.branchOffsets.resize(max - min + 1);
+    jumpTable.branchOffsets.fill(0);
+    for (uint32_t i = 0; i < clauseCount; ++i) {
+        // We're emitting this after the clause labels should have been fixed, so 
+        // the labels should not be "forward" references
+        ASSERT(!labels[i]->isForward());
+        jumpTable.add(keyForImmediateSwitch(nodes[i], min, max), labels[i]->bind(switchAddress, switchAddress + 3)); 
+    }
+}
+
+static int32_t keyForCharacterSwitch(ExpressionNode* node, int32_t min, int32_t max)
+{
+    UNUSED_PARAM(max);
+    ASSERT(node->isString());
+    StringImpl* clause = static_cast<StringNode*>(node)->value().impl();
+    ASSERT(clause->length() == 1);
+    
+    int32_t key = clause->characters()[0];
+    ASSERT(key >= min);
+    ASSERT(key <= max);
+    return key - min;
+}
+
+static void prepareJumpTableForCharacterSwitch(SimpleJumpTable& jumpTable, int32_t switchAddress, uint32_t clauseCount, RefPtr<Label>* labels, ExpressionNode** nodes, int32_t min, int32_t max)
+{
+    jumpTable.min = min;
+    jumpTable.branchOffsets.resize(max - min + 1);
+    jumpTable.branchOffsets.fill(0);
+    for (uint32_t i = 0; i < clauseCount; ++i) {
+        // We're emitting this after the clause labels should have been fixed, so 
+        // the labels should not be "forward" references
+        ASSERT(!labels[i]->isForward());
+        jumpTable.add(keyForCharacterSwitch(nodes[i], min, max), labels[i]->bind(switchAddress, switchAddress + 3)); 
+    }
+}
+
+static void prepareJumpTableForStringSwitch(StringJumpTable& jumpTable, int32_t switchAddress, uint32_t clauseCount, RefPtr<Label>* labels, ExpressionNode** nodes)
+{
+    for (uint32_t i = 0; i < clauseCount; ++i) {
+        // We're emitting this after the clause labels should have been fixed, so 
+        // the labels should not be "forward" references
+        ASSERT(!labels[i]->isForward());
+        
+        ASSERT(nodes[i]->isString());
+        StringImpl* clause = static_cast<StringNode*>(nodes[i])->value().impl();
+        OffsetLocation location;
+        location.branchOffset = labels[i]->bind(switchAddress, switchAddress + 3);
+        jumpTable.offsetTable.add(clause, location);
+    }
+}
+
+void BytecodeGenerator::endSwitch(uint32_t clauseCount, RefPtr<Label>* labels, ExpressionNode** nodes, Label* defaultLabel, int32_t min, int32_t max)
+{
+    SwitchInfo switchInfo = m_switchContextStack.last();
+    m_switchContextStack.removeLast();
+    if (switchInfo.switchType == SwitchInfo::SwitchImmediate) {
+        instructions()[switchInfo.bytecodeOffset + 1] = m_codeBlock->numberOfImmediateSwitchJumpTables();
+        instructions()[switchInfo.bytecodeOffset + 2] = defaultLabel->bind(switchInfo.bytecodeOffset, switchInfo.bytecodeOffset + 3);
+
+        SimpleJumpTable& jumpTable = m_codeBlock->addImmediateSwitchJumpTable();
+        prepareJumpTableForImmediateSwitch(jumpTable, switchInfo.bytecodeOffset, clauseCount, labels, nodes, min, max);
+    } else if (switchInfo.switchType == SwitchInfo::SwitchCharacter) {
+        instructions()[switchInfo.bytecodeOffset + 1] = m_codeBlock->numberOfCharacterSwitchJumpTables();
+        instructions()[switchInfo.bytecodeOffset + 2] = defaultLabel->bind(switchInfo.bytecodeOffset, switchInfo.bytecodeOffset + 3);
+        
+        SimpleJumpTable& jumpTable = m_codeBlock->addCharacterSwitchJumpTable();
+        prepareJumpTableForCharacterSwitch(jumpTable, switchInfo.bytecodeOffset, clauseCount, labels, nodes, min, max);
+    } else {
+        ASSERT(switchInfo.switchType == SwitchInfo::SwitchString);
+        instructions()[switchInfo.bytecodeOffset + 1] = m_codeBlock->numberOfStringSwitchJumpTables();
+        instructions()[switchInfo.bytecodeOffset + 2] = defaultLabel->bind(switchInfo.bytecodeOffset, switchInfo.bytecodeOffset + 3);
+
+        StringJumpTable& jumpTable = m_codeBlock->addStringSwitchJumpTable();
+        prepareJumpTableForStringSwitch(jumpTable, switchInfo.bytecodeOffset, clauseCount, labels, nodes);
+    }
+}
+
+RegisterID* BytecodeGenerator::emitThrowExpressionTooDeepException()
+{
+    // It would be nice to do an even better job of identifying exactly where the expression is.
+    // And we could make the caller pass the node pointer in, if there was some way of getting
+    // that from an arbitrary node. However, calling emitExpressionInfo without any useful data
+    // is still good enough to get us an accurate line number.
+    emitExpressionInfo(0, 0, 0);
+    emitThrowSyntaxError("Expression too deep");
+    return newTemporary();
+}
+
+void BytecodeGenerator::setIsNumericCompareFunction(bool isNumericCompareFunction)
+{
+    m_codeBlock->setIsNumericCompareFunction(isNumericCompareFunction);
+}
+
+int BytecodeGenerator::argumentNumberFor(const Identifier& ident)
+{
+    int parameterCount = m_parameters.size(); // includes 'this'
+    RegisterID* registerID = registerFor(ident);
+    if (!registerID)
+        return 0;
+    int index = registerID->index() + RegisterFile::CallFrameHeaderSize + parameterCount;
+    return (index > 0 && index < parameterCount) ? index : 0;
+}
+
+} // namespace JSC
diff --git a/Source/JavaScriptCore/bytecompiler/BytecodeGenerator.h b/Source/JavaScriptCore/bytecompiler/BytecodeGenerator.h
new file mode 100644
index 0000000..37756fa
--- /dev/null
+++ b/Source/JavaScriptCore/bytecompiler/BytecodeGenerator.h
@@ -0,0 +1,588 @@
+/*
+ * Copyright (C) 2008, 2009 Apple Inc. All rights reserved.
+ * Copyright (C) 2008 Cameron Zwarich <cwzwarich@uwaterloo.ca>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1.  Redistributions of source code must retain the above copyright
+ *     notice, this list of conditions and the following disclaimer.
+ * 2.  Redistributions in binary form must reproduce the above copyright
+ *     notice, this list of conditions and the following disclaimer in the
+ *     documentation and/or other materials provided with the distribution.
+ * 3.  Neither the name of Apple Computer, Inc. ("Apple") nor the names of
+ *     its contributors may be used to endorse or promote products derived
+ *     from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef BytecodeGenerator_h
+#define BytecodeGenerator_h
+
+#include "CodeBlock.h"
+#include "HashTraits.h"
+#include "Instruction.h"
+#include "Label.h"
+#include "LabelScope.h"
+#include "Interpreter.h"
+#include "RegisterID.h"
+#include "SymbolTable.h"
+#include "Debugger.h"
+#include "Nodes.h"
+#include <wtf/FastAllocBase.h>
+#include <wtf/PassRefPtr.h>
+#include <wtf/SegmentedVector.h>
+#include <wtf/Vector.h>
+
+namespace JSC {
+
+    class Identifier;
+    class ScopeChain;
+    class ScopeNode;
+
+    class CallArguments {
+    public:
+        CallArguments(BytecodeGenerator& generator, ArgumentsNode* argumentsNode);
+
+        RegisterID* thisRegister() { return m_argv[0].get(); }
+        RegisterID* argumentRegister(unsigned i) { return m_argv[i + 1].get(); }
+        unsigned callFrame() { return thisRegister()->index() + count() + RegisterFile::CallFrameHeaderSize; }
+        unsigned count() { return m_argv.size(); }
+        RegisterID* profileHookRegister() { return m_profileHookRegister.get(); }
+        ArgumentsNode* argumentsNode() { return m_argumentsNode; }
+
+    private:
+        RefPtr<RegisterID> m_profileHookRegister;
+        ArgumentsNode* m_argumentsNode;
+        Vector<RefPtr<RegisterID>, 16> m_argv;
+    };
+
+    struct FinallyContext {
+        Label* finallyAddr;
+        RegisterID* retAddrDst;
+    };
+
+    struct ControlFlowContext {
+        bool isFinallyBlock;
+        FinallyContext finallyContext;
+    };
+
+    struct ForInContext {
+        RefPtr<RegisterID> expectedSubscriptRegister;
+        RefPtr<RegisterID> iterRegister;
+        RefPtr<RegisterID> indexRegister;
+        RefPtr<RegisterID> propertyRegister;
+    };
+
+    class BytecodeGenerator : public FastAllocBase {
+    public:
+        typedef DeclarationStacks::VarStack VarStack;
+        typedef DeclarationStacks::FunctionStack FunctionStack;
+
+        static void setDumpsGeneratedCode(bool dumpsGeneratedCode);
+        static bool dumpsGeneratedCode();
+
+        BytecodeGenerator(ProgramNode*, const ScopeChain&, SymbolTable*, ProgramCodeBlock*);
+        BytecodeGenerator(FunctionBodyNode*, const ScopeChain&, SymbolTable*, CodeBlock*);
+        BytecodeGenerator(EvalNode*, const ScopeChain&, SymbolTable*, EvalCodeBlock*);
+
+        JSGlobalData* globalData() const { return m_globalData; }
+        const CommonIdentifiers& propertyNames() const { return *m_globalData->propertyNames; }
+
+        bool isConstructor() { return m_codeBlock->m_isConstructor; }
+
+        void generate();
+
+        // Returns the register corresponding to a local variable, or 0 if no
+        // such register exists. Registers returned by registerFor do not
+        // require explicit reference counting.
+        RegisterID* registerFor(const Identifier&);
+
+        // Returns the agument number if this is an argument, or 0 if not.
+        int argumentNumberFor(const Identifier&);
+
+        void setIsNumericCompareFunction(bool isNumericCompareFunction);
+
+        bool willResolveToArguments(const Identifier&);
+        RegisterID* uncheckedRegisterForArguments();
+
+        // Behaves as registerFor does, but ignores dynamic scope as
+        // dynamic scope should not interfere with const initialisation
+        RegisterID* constRegisterFor(const Identifier&);
+
+        // Searches the scope chain in an attempt to  statically locate the requested
+        // property.  Returns false if for any reason the property cannot be safely
+        // optimised at all.  Otherwise it will return the index and depth of the
+        // VariableObject that defines the property.  If the property cannot be found
+        // statically, depth will contain the depth of the scope chain where dynamic
+        // lookup must begin.
+        bool findScopedProperty(const Identifier&, int& index, size_t& depth, bool forWriting, bool& includesDynamicScopes, JSObject*& globalObject);
+
+        // Returns the register storing "this"
+        RegisterID* thisRegister() { return &m_thisRegister; }
+
+        bool isLocal(const Identifier&);
+        bool isLocalConstant(const Identifier&);
+
+        // Returns the next available temporary register. Registers returned by
+        // newTemporary require a modified form of reference counting: any
+        // register with a refcount of 0 is considered "available", meaning that
+        // the next instruction may overwrite it.
+        RegisterID* newTemporary();
+
+        RegisterID* highestUsedRegister();
+
+        // The same as newTemporary(), but this function returns "suggestion" if
+        // "suggestion" is a temporary. This function is helpful in situations
+        // where you've put "suggestion" in a RefPtr, but you'd like to allow
+        // the next instruction to overwrite it anyway.
+        RegisterID* newTemporaryOr(RegisterID* suggestion) { return suggestion->isTemporary() ? suggestion : newTemporary(); }
+
+        // Functions for handling of dst register
+
+        RegisterID* ignoredResult() { return &m_ignoredResultRegister; }
+
+        // Returns a place to write intermediate values of an operation
+        // which reuses dst if it is safe to do so.
+        RegisterID* tempDestination(RegisterID* dst)
+        {
+            return (dst && dst != ignoredResult() && dst->isTemporary()) ? dst : newTemporary();
+        }
+
+        // Returns the place to write the final output of an operation.
+        RegisterID* finalDestination(RegisterID* originalDst, RegisterID* tempDst = 0)
+        {
+            if (originalDst && originalDst != ignoredResult())
+                return originalDst;
+            ASSERT(tempDst != ignoredResult());
+            if (tempDst && tempDst->isTemporary())
+                return tempDst;
+            return newTemporary();
+        }
+
+        // Returns the place to write the final output of an operation.
+        RegisterID* finalDestinationOrIgnored(RegisterID* originalDst, RegisterID* tempDst = 0)
+        {
+            if (originalDst)
+                return originalDst;
+            ASSERT(tempDst != ignoredResult());
+            if (tempDst && tempDst->isTemporary())
+                return tempDst;
+            return newTemporary();
+        }
+
+        RegisterID* destinationForAssignResult(RegisterID* dst)
+        {
+            if (dst && dst != ignoredResult() && m_codeBlock->needsFullScopeChain())
+                return dst->isTemporary() ? dst : newTemporary();
+            return 0;
+        }
+
+        // Moves src to dst if dst is not null and is different from src, otherwise just returns src.
+        RegisterID* moveToDestinationIfNeeded(RegisterID* dst, RegisterID* src)
+        {
+            return dst == ignoredResult() ? 0 : (dst && dst != src) ? emitMove(dst, src) : src;
+        }
+
+        PassRefPtr<LabelScope> newLabelScope(LabelScope::Type, const Identifier* = 0);
+        PassRefPtr<Label> newLabel();
+
+        // The emitNode functions are just syntactic sugar for calling
+        // Node::emitCode. These functions accept a 0 for the register,
+        // meaning that the node should allocate a register, or ignoredResult(),
+        // meaning that the node need not put the result in a register.
+        // Other emit functions do not accept 0 or ignoredResult().
+        RegisterID* emitNode(RegisterID* dst, Node* n)
+        {
+            // Node::emitCode assumes that dst, if provided, is either a local or a referenced temporary.
+            ASSERT(!dst || dst == ignoredResult() || !dst->isTemporary() || dst->refCount());
+            addLineInfo(n->lineNo());
+            return m_stack.recursionCheck()
+                ? n->emitBytecode(*this, dst)
+                : emitThrowExpressionTooDeepException();
+        }
+
+        RegisterID* emitNode(Node* n)
+        {
+            return emitNode(0, n);
+        }
+
+        void emitNodeInConditionContext(ExpressionNode* n, Label* trueTarget, Label* falseTarget, bool fallThroughMeansTrue)
+        {
+            addLineInfo(n->lineNo());
+            if (m_stack.recursionCheck())
+                n->emitBytecodeInConditionContext(*this, trueTarget, falseTarget, fallThroughMeansTrue);
+            else
+                emitThrowExpressionTooDeepException();
+        }
+
+        void emitExpressionInfo(unsigned divot, unsigned startOffset, unsigned endOffset)
+        {
+            if (!m_shouldEmitRichSourceInfo)
+                return;
+
+            divot -= m_codeBlock->sourceOffset();
+            if (divot > ExpressionRangeInfo::MaxDivot) {
+                // Overflow has occurred, we can only give line number info for errors for this region
+                divot = 0;
+                startOffset = 0;
+                endOffset = 0;
+            } else if (startOffset > ExpressionRangeInfo::MaxOffset) {
+                // If the start offset is out of bounds we clear both offsets
+                // so we only get the divot marker.  Error message will have to be reduced
+                // to line and column number.
+                startOffset = 0;
+                endOffset = 0;
+            } else if (endOffset > ExpressionRangeInfo::MaxOffset) {
+                // The end offset is only used for additional context, and is much more likely
+                // to overflow (eg. function call arguments) so we are willing to drop it without
+                // dropping the rest of the range.
+                endOffset = 0;
+            }
+            
+            ExpressionRangeInfo info;
+            info.instructionOffset = instructions().size();
+            info.divotPoint = divot;
+            info.startOffset = startOffset;
+            info.endOffset = endOffset;
+            m_codeBlock->addExpressionInfo(info);
+        }
+
+        ALWAYS_INLINE bool leftHandSideNeedsCopy(bool rightHasAssignments, bool rightIsPure)
+        {
+            return (m_codeType != FunctionCode || m_codeBlock->needsFullScopeChain() || rightHasAssignments) && !rightIsPure;
+        }
+
+        ALWAYS_INLINE PassRefPtr<RegisterID> emitNodeForLeftHandSide(ExpressionNode* n, bool rightHasAssignments, bool rightIsPure)
+        {
+            if (leftHandSideNeedsCopy(rightHasAssignments, rightIsPure)) {
+                PassRefPtr<RegisterID> dst = newTemporary();
+                emitNode(dst.get(), n);
+                return dst;
+            }
+
+            return PassRefPtr<RegisterID>(emitNode(n));
+        }
+
+        RegisterID* emitLoad(RegisterID* dst, bool);
+        RegisterID* emitLoad(RegisterID* dst, double);
+        RegisterID* emitLoad(RegisterID* dst, const Identifier&);
+        RegisterID* emitLoad(RegisterID* dst, JSValue);
+
+        RegisterID* emitUnaryOp(OpcodeID, RegisterID* dst, RegisterID* src);
+        RegisterID* emitBinaryOp(OpcodeID, RegisterID* dst, RegisterID* src1, RegisterID* src2, OperandTypes);
+        RegisterID* emitEqualityOp(OpcodeID, RegisterID* dst, RegisterID* src1, RegisterID* src2);
+        RegisterID* emitUnaryNoDstOp(OpcodeID, RegisterID* src);
+
+        RegisterID* emitNewObject(RegisterID* dst);
+        RegisterID* emitNewArray(RegisterID* dst, ElementNode*); // stops at first elision
+
+        RegisterID* emitNewFunction(RegisterID* dst, FunctionBodyNode* body);
+        RegisterID* emitLazyNewFunction(RegisterID* dst, FunctionBodyNode* body);
+        RegisterID* emitNewFunctionInternal(RegisterID* dst, unsigned index, bool shouldNullCheck);
+        RegisterID* emitNewFunctionExpression(RegisterID* dst, FuncExprNode* func);
+        RegisterID* emitNewRegExp(RegisterID* dst, RegExp* regExp);
+
+        RegisterID* emitMove(RegisterID* dst, RegisterID* src);
+
+        RegisterID* emitToJSNumber(RegisterID* dst, RegisterID* src) { return emitUnaryOp(op_to_jsnumber, dst, src); }
+        RegisterID* emitPreInc(RegisterID* srcDst);
+        RegisterID* emitPreDec(RegisterID* srcDst);
+        RegisterID* emitPostInc(RegisterID* dst, RegisterID* srcDst);
+        RegisterID* emitPostDec(RegisterID* dst, RegisterID* srcDst);
+
+        void emitCheckHasInstance(RegisterID* base);
+        RegisterID* emitInstanceOf(RegisterID* dst, RegisterID* value, RegisterID* base, RegisterID* basePrototype);
+        RegisterID* emitTypeOf(RegisterID* dst, RegisterID* src) { return emitUnaryOp(op_typeof, dst, src); }
+        RegisterID* emitIn(RegisterID* dst, RegisterID* property, RegisterID* base) { return emitBinaryOp(op_in, dst, property, base, OperandTypes()); }
+
+        RegisterID* emitResolve(RegisterID* dst, const Identifier& property);
+        RegisterID* emitGetScopedVar(RegisterID* dst, size_t skip, int index, JSValue globalObject);
+        RegisterID* emitPutScopedVar(size_t skip, int index, RegisterID* value, JSValue globalObject);
+
+        RegisterID* emitResolveBase(RegisterID* dst, const Identifier& property);
+        RegisterID* emitResolveBaseForPut(RegisterID* dst, const Identifier& property);
+        RegisterID* emitResolveWithBase(RegisterID* baseDst, RegisterID* propDst, const Identifier& property);
+
+        void emitMethodCheck();
+
+        RegisterID* emitGetById(RegisterID* dst, RegisterID* base, const Identifier& property);
+        RegisterID* emitGetArgumentsLength(RegisterID* dst, RegisterID* base);
+        RegisterID* emitPutById(RegisterID* base, const Identifier& property, RegisterID* value);
+        RegisterID* emitDirectPutById(RegisterID* base, const Identifier& property, RegisterID* value);
+        RegisterID* emitDeleteById(RegisterID* dst, RegisterID* base, const Identifier&);
+        RegisterID* emitGetByVal(RegisterID* dst, RegisterID* base, RegisterID* property);
+        RegisterID* emitGetArgumentByVal(RegisterID* dst, RegisterID* base, RegisterID* property);
+        RegisterID* emitPutByVal(RegisterID* base, RegisterID* property, RegisterID* value);
+        RegisterID* emitDeleteByVal(RegisterID* dst, RegisterID* base, RegisterID* property);
+        RegisterID* emitPutByIndex(RegisterID* base, unsigned index, RegisterID* value);
+        RegisterID* emitPutGetter(RegisterID* base, const Identifier& property, RegisterID* value);
+        RegisterID* emitPutSetter(RegisterID* base, const Identifier& property, RegisterID* value);
+
+        RegisterID* emitCall(RegisterID* dst, RegisterID* func, CallArguments&, unsigned divot, unsigned startOffset, unsigned endOffset);
+        RegisterID* emitCallEval(RegisterID* dst, RegisterID* func, CallArguments&, unsigned divot, unsigned startOffset, unsigned endOffset);
+        RegisterID* emitCallVarargs(RegisterID* dst, RegisterID* func, RegisterID* thisRegister, RegisterID* argCount, unsigned divot, unsigned startOffset, unsigned endOffset);
+        RegisterID* emitLoadVarargs(RegisterID* argCountDst, RegisterID* thisRegister, RegisterID* args);
+
+        RegisterID* emitReturn(RegisterID* src);
+        RegisterID* emitEnd(RegisterID* src) { return emitUnaryNoDstOp(op_end, src); }
+
+        RegisterID* emitConstruct(RegisterID* dst, RegisterID* func, CallArguments&, unsigned divot, unsigned startOffset, unsigned endOffset);
+        RegisterID* emitStrcat(RegisterID* dst, RegisterID* src, int count);
+        void emitToPrimitive(RegisterID* dst, RegisterID* src);
+
+        PassRefPtr<Label> emitLabel(Label*);
+        PassRefPtr<Label> emitJump(Label* target);
+        PassRefPtr<Label> emitJumpIfTrue(RegisterID* cond, Label* target);
+        PassRefPtr<Label> emitJumpIfFalse(RegisterID* cond, Label* target);
+        PassRefPtr<Label> emitJumpIfNotFunctionCall(RegisterID* cond, Label* target);
+        PassRefPtr<Label> emitJumpIfNotFunctionApply(RegisterID* cond, Label* target);
+        PassRefPtr<Label> emitJumpScopes(Label* target, int targetScopeDepth);
+
+        PassRefPtr<Label> emitJumpSubroutine(RegisterID* retAddrDst, Label*);
+        void emitSubroutineReturn(RegisterID* retAddrSrc);
+
+        RegisterID* emitGetPropertyNames(RegisterID* dst, RegisterID* base, RegisterID* i, RegisterID* size, Label* breakTarget);
+        RegisterID* emitNextPropertyName(RegisterID* dst, RegisterID* base, RegisterID* i, RegisterID* size, RegisterID* iter, Label* target);
+
+        RegisterID* emitCatch(RegisterID*, Label* start, Label* end);
+        void emitThrow(RegisterID* exc)
+        { 
+            m_usesExceptions = true;
+            emitUnaryNoDstOp(op_throw, exc);
+        }
+
+        void emitThrowReferenceError(const UString& message);
+        void emitThrowSyntaxError(const UString& message);
+
+        void emitPushNewScope(RegisterID* dst, const Identifier& property, RegisterID* value);
+
+        RegisterID* emitPushScope(RegisterID* scope);
+        void emitPopScope();
+
+        void emitDebugHook(DebugHookID, int firstLine, int lastLine);
+
+        int scopeDepth() { return m_dynamicScopeDepth + m_finallyDepth; }
+        bool hasFinaliser() { return m_finallyDepth != 0; }
+
+        void pushFinallyContext(Label* target, RegisterID* returnAddrDst);
+        void popFinallyContext();
+
+        void pushOptimisedForIn(RegisterID* expectedBase, RegisterID* iter, RegisterID* index, RegisterID* propertyRegister)
+        {
+            ForInContext context = { expectedBase, iter, index, propertyRegister };
+            m_forInContextStack.append(context);
+        }
+
+        void popOptimisedForIn()
+        {
+            m_forInContextStack.removeLast();
+        }
+
+        LabelScope* breakTarget(const Identifier&);
+        LabelScope* continueTarget(const Identifier&);
+
+        void beginSwitch(RegisterID*, SwitchInfo::SwitchType);
+        void endSwitch(uint32_t clauseCount, RefPtr<Label>*, ExpressionNode**, Label* defaultLabel, int32_t min, int32_t range);
+
+        CodeType codeType() const { return m_codeType; }
+
+        void setRegeneratingForExceptionInfo(CodeBlock* originalCodeBlock)
+        {
+            m_regeneratingForExceptionInfo = true;
+            m_codeBlockBeingRegeneratedFrom = originalCodeBlock;
+        }
+
+        bool shouldEmitProfileHooks() { return m_shouldEmitProfileHooks; }
+        
+        bool isStrictMode() const { return m_codeBlock->isStrictMode(); }
+
+    private:
+        void emitOpcode(OpcodeID);
+        void retrieveLastBinaryOp(int& dstIndex, int& src1Index, int& src2Index);
+        void retrieveLastUnaryOp(int& dstIndex, int& srcIndex);
+        ALWAYS_INLINE void rewindBinaryOp();
+        ALWAYS_INLINE void rewindUnaryOp();
+
+        PassRefPtr<Label> emitComplexJumpScopes(Label* target, ControlFlowContext* topScope, ControlFlowContext* bottomScope);
+
+        typedef HashMap<EncodedJSValue, unsigned, EncodedJSValueHash, EncodedJSValueHashTraits> JSValueMap;
+
+        struct IdentifierMapIndexHashTraits {
+            typedef int TraitType;
+            typedef IdentifierMapIndexHashTraits StorageTraits;
+            static int emptyValue() { return std::numeric_limits<int>::max(); }
+            static const bool emptyValueIsZero = false;
+            static const bool needsDestruction = false;
+            static const bool needsRef = false;
+        };
+
+        typedef HashMap<RefPtr<StringImpl>, int, IdentifierRepHash, HashTraits<RefPtr<StringImpl> >, IdentifierMapIndexHashTraits> IdentifierMap;
+        typedef HashMap<double, JSValue> NumberMap;
+        typedef HashMap<StringImpl*, JSString*, IdentifierRepHash> IdentifierStringMap;
+        
+        RegisterID* emitCall(OpcodeID, RegisterID* dst, RegisterID* func, CallArguments&, unsigned divot, unsigned startOffset, unsigned endOffset);
+
+        RegisterID* newRegister();
+
+        // Adds a var slot and maps it to the name ident in symbolTable().
+        RegisterID* addVar(const Identifier& ident, bool isConstant)
+        {
+            RegisterID* local;
+            addVar(ident, isConstant, local);
+            return local;
+        }
+
+        // Ditto. Returns true if a new RegisterID was added, false if a pre-existing RegisterID was re-used.
+        bool addVar(const Identifier&, bool isConstant, RegisterID*&);
+        
+        // Adds an anonymous var slot. To give this slot a name, add it to symbolTable().
+        RegisterID* addVar()
+        {
+            ++m_codeBlock->m_numVars;
+            return newRegister();
+        }
+
+        // Returns the RegisterID corresponding to ident.
+        RegisterID* addGlobalVar(const Identifier& ident, bool isConstant)
+        {
+            RegisterID* local;
+            addGlobalVar(ident, isConstant, local);
+            return local;
+        }
+        // Returns true if a new RegisterID was added, false if a pre-existing RegisterID was re-used.
+        bool addGlobalVar(const Identifier&, bool isConstant, RegisterID*&);
+
+        void addParameter(const Identifier&, int parameterIndex);
+        
+        void preserveLastVar();
+
+        RegisterID& registerFor(int index)
+        {
+            if (index >= 0)
+                return m_calleeRegisters[index];
+
+            if (m_parameters.size()) {
+                ASSERT(!m_globals.size());
+                return m_parameters[index + m_parameters.size() + RegisterFile::CallFrameHeaderSize];
+            }
+
+            return m_globals[-index - 1];
+        }
+
+        unsigned addConstant(const Identifier&);
+        RegisterID* addConstantValue(JSValue);
+        unsigned addRegExp(RegExp*);
+
+        PassRefPtr<FunctionExecutable> makeFunction(ExecState* exec, FunctionBodyNode* body)
+        {
+            return FunctionExecutable::create(exec, body->ident(), body->source(), body->usesArguments(), body->parameters(), body->isStrictMode(), body->lineNo(), body->lastLine());
+        }
+
+        PassRefPtr<FunctionExecutable> makeFunction(JSGlobalData* globalData, FunctionBodyNode* body)
+        {
+            return FunctionExecutable::create(globalData, body->ident(), body->source(), body->usesArguments(), body->parameters(), body->isStrictMode(), body->lineNo(), body->lastLine());
+        }
+
+        void addLineInfo(unsigned lineNo)
+        {
+#if !ENABLE(OPCODE_SAMPLING)
+            if (m_shouldEmitRichSourceInfo)
+#endif
+                m_codeBlock->addLineInfo(instructions().size(), lineNo);
+        }
+
+        RegisterID* emitInitLazyRegister(RegisterID*);
+
+        Vector<Instruction>& instructions() { return m_codeBlock->instructions(); }
+        SymbolTable& symbolTable() { return *m_symbolTable; }
+
+        bool shouldOptimizeLocals() { return (m_codeType != EvalCode) && !m_dynamicScopeDepth; }
+        bool canOptimizeNonLocals() { return (m_codeType == FunctionCode) && !m_dynamicScopeDepth && !m_codeBlock->usesEval(); }
+
+        RegisterID* emitThrowExpressionTooDeepException();
+
+        void createArgumentsIfNecessary();
+        void createActivationIfNecessary();
+        RegisterID* createLazyRegisterIfNecessary(RegisterID*);
+
+        bool m_shouldEmitDebugHooks;
+        bool m_shouldEmitProfileHooks;
+        bool m_shouldEmitRichSourceInfo;
+
+        const ScopeChain* m_scopeChain;
+        SymbolTable* m_symbolTable;
+
+        ScopeNode* m_scopeNode;
+        CodeBlock* m_codeBlock;
+
+        // Some of these objects keep pointers to one another. They are arranged
+        // to ensure a sane destruction order that avoids references to freed memory.
+        HashSet<RefPtr<StringImpl>, IdentifierRepHash> m_functions;
+        RegisterID m_ignoredResultRegister;
+        RegisterID m_thisRegister;
+        RegisterID* m_activationRegister;
+        SegmentedVector<RegisterID, 32> m_constantPoolRegisters;
+        SegmentedVector<RegisterID, 32> m_calleeRegisters;
+        SegmentedVector<RegisterID, 32> m_parameters;
+        SegmentedVector<RegisterID, 32> m_globals;
+        SegmentedVector<Label, 32> m_labels;
+        SegmentedVector<LabelScope, 8> m_labelScopes;
+        RefPtr<RegisterID> m_lastVar;
+        int m_finallyDepth;
+        int m_dynamicScopeDepth;
+        int m_baseScopeDepth;
+        CodeType m_codeType;
+
+        Vector<ControlFlowContext> m_scopeContextStack;
+        Vector<SwitchInfo> m_switchContextStack;
+        Vector<ForInContext> m_forInContextStack;
+
+        int m_nextGlobalIndex;
+        int m_firstConstantIndex;
+        int m_nextConstantOffset;
+        unsigned m_globalConstantIndex;
+
+        int m_globalVarStorageOffset;
+
+        bool m_hasCreatedActivation;
+        int m_firstLazyFunction;
+        int m_lastLazyFunction;
+        HashMap<unsigned int, FunctionBodyNode*, WTF::IntHash<unsigned int>, WTF::UnsignedWithZeroKeyHashTraits<unsigned int> > m_lazyFunctions;
+        typedef HashMap<FunctionBodyNode*, unsigned> FunctionOffsetMap;
+        FunctionOffsetMap m_functionOffsets;
+        
+        // Constant pool
+        IdentifierMap m_identifierMap;
+        JSValueMap m_jsValueMap;
+        NumberMap m_numberMap;
+        IdentifierStringMap m_stringMap;
+
+        JSGlobalData* m_globalData;
+
+        OpcodeID m_lastOpcodeID;
+#ifndef NDEBUG
+        size_t m_lastOpcodePosition;
+#endif
+
+        StackBounds m_stack;
+
+        bool m_usesExceptions;
+        bool m_regeneratingForExceptionInfo;
+        CodeBlock* m_codeBlockBeingRegeneratedFrom;
+    };
+
+}
+
+#endif // BytecodeGenerator_h
diff --git a/Source/JavaScriptCore/bytecompiler/Label.h b/Source/JavaScriptCore/bytecompiler/Label.h
new file mode 100644
index 0000000..8cab1db
--- /dev/null
+++ b/Source/JavaScriptCore/bytecompiler/Label.h
@@ -0,0 +1,90 @@
+/*
+ * Copyright (C) 2008 Apple Inc. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1.  Redistributions of source code must retain the above copyright
+ *     notice, this list of conditions and the following disclaimer.
+ * 2.  Redistributions in binary form must reproduce the above copyright
+ *     notice, this list of conditions and the following disclaimer in the
+ *     documentation and/or other materials provided with the distribution.
+ * 3.  Neither the name of Apple Computer, Inc. ("Apple") nor the names of
+ *     its contributors may be used to endorse or promote products derived
+ *     from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef Label_h
+#define Label_h
+
+#include "CodeBlock.h"
+#include "Instruction.h"
+#include <wtf/Assertions.h>
+#include <wtf/Vector.h>
+#include <limits.h>
+
+namespace JSC {
+
+    class Label {
+    public:
+        explicit Label(CodeBlock* codeBlock)
+            : m_refCount(0)
+            , m_location(invalidLocation)
+            , m_codeBlock(codeBlock)
+        {
+        }
+
+        void setLocation(unsigned location)
+        {
+            m_location = location;
+
+            unsigned size = m_unresolvedJumps.size();
+            for (unsigned i = 0; i < size; ++i)
+                m_codeBlock->instructions()[m_unresolvedJumps[i].second].u.operand = m_location - m_unresolvedJumps[i].first;
+        }
+
+        int bind(int opcode, int offset) const
+        {
+            if (m_location == invalidLocation) {
+                m_unresolvedJumps.append(std::make_pair(opcode, offset));
+                return 0;
+            }
+            return m_location - opcode;
+        }
+
+        void ref() { ++m_refCount; }
+        void deref()
+        {
+            --m_refCount;
+            ASSERT(m_refCount >= 0);
+        }
+        int refCount() const { return m_refCount; }
+
+        bool isForward() const { return m_location == invalidLocation; }
+
+    private:
+        typedef Vector<std::pair<int, int>, 8> JumpVector;
+
+        static const unsigned invalidLocation = UINT_MAX;
+
+        int m_refCount;
+        unsigned m_location;
+        CodeBlock* m_codeBlock;
+        mutable JumpVector m_unresolvedJumps;
+    };
+
+} // namespace JSC
+
+#endif // Label_h
diff --git a/Source/JavaScriptCore/bytecompiler/LabelScope.h b/Source/JavaScriptCore/bytecompiler/LabelScope.h
new file mode 100644
index 0000000..cc21fff
--- /dev/null
+++ b/Source/JavaScriptCore/bytecompiler/LabelScope.h
@@ -0,0 +1,79 @@
+/*
+ * Copyright (C) 2008 Apple Inc. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1.  Redistributions of source code must retain the above copyright
+ *     notice, this list of conditions and the following disclaimer.
+ * 2.  Redistributions in binary form must reproduce the above copyright
+ *     notice, this list of conditions and the following disclaimer in the
+ *     documentation and/or other materials provided with the distribution.
+ * 3.  Neither the name of Apple Computer, Inc. ("Apple") nor the names of
+ *     its contributors may be used to endorse or promote products derived
+ *     from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef LabelScope_h
+#define LabelScope_h
+
+#include <wtf/PassRefPtr.h>
+#include "Label.h"
+
+namespace JSC {
+
+    class Identifier;
+
+    class LabelScope {
+    public:
+        enum Type { Loop, Switch, NamedLabel };
+
+        LabelScope(Type type, const Identifier* name, int scopeDepth, PassRefPtr<Label> breakTarget, PassRefPtr<Label> continueTarget)
+            : m_refCount(0)
+            , m_type(type)
+            , m_name(name)
+            , m_scopeDepth(scopeDepth)
+            , m_breakTarget(breakTarget)
+            , m_continueTarget(continueTarget)
+        {
+        }
+
+        void ref() { ++m_refCount; }
+        void deref()
+        {
+            --m_refCount;
+            ASSERT(m_refCount >= 0);
+        }
+        int refCount() const { return m_refCount; }
+
+        Label* breakTarget() const { return m_breakTarget.get(); }
+        Label* continueTarget() const { return m_continueTarget.get(); }
+
+        Type type() const { return m_type; }
+        const Identifier* name() const { return m_name; }
+        int scopeDepth() const { return m_scopeDepth; }
+
+    private:
+        int m_refCount;
+        Type m_type;
+        const Identifier* m_name;
+        int m_scopeDepth;
+        RefPtr<Label> m_breakTarget;
+        RefPtr<Label> m_continueTarget;
+    };
+
+} // namespace JSC
+
+#endif // LabelScope_h
diff --git a/Source/JavaScriptCore/bytecompiler/NodesCodegen.cpp b/Source/JavaScriptCore/bytecompiler/NodesCodegen.cpp
new file mode 100644
index 0000000..a850c96
--- /dev/null
+++ b/Source/JavaScriptCore/bytecompiler/NodesCodegen.cpp
@@ -0,0 +1,2076 @@
+/*
+*  Copyright (C) 1999-2002 Harri Porten (porten@kde.org)
+*  Copyright (C) 2001 Peter Kelly (pmk@post.com)
+*  Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009 Apple Inc. All rights reserved.
+*  Copyright (C) 2007 Cameron Zwarich (cwzwarich@uwaterloo.ca)
+*  Copyright (C) 2007 Maks Orlovich
+*  Copyright (C) 2007 Eric Seidel <eric@webkit.org>
+*
+*  This library is free software; you can redistribute it and/or
+*  modify it under the terms of the GNU Library General Public
+*  License as published by the Free Software Foundation; either
+*  version 2 of the License, or (at your option) any later version.
+*
+*  This library is distributed in the hope that it will be useful,
+*  but WITHOUT ANY WARRANTY; without even the implied warranty of
+*  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+*  Library General Public License for more details.
+*
+*  You should have received a copy of the GNU Library General Public License
+*  along with this library; see the file COPYING.LIB.  If not, write to
+*  the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+*  Boston, MA 02110-1301, USA.
+*
+*/
+
+#include "config.h"
+#include "Nodes.h"
+#include "NodeConstructors.h"
+
+#include "BytecodeGenerator.h"
+#include "CallFrame.h"
+#include "Debugger.h"
+#include "JIT.h"
+#include "JSFunction.h"
+#include "JSGlobalObject.h"
+#include "JSStaticScopeObject.h"
+#include "LabelScope.h"
+#include "Lexer.h"
+#include "Operations.h"
+#include "Parser.h"
+#include "PropertyNameArray.h"
+#include "RegExpCache.h"
+#include "RegExpObject.h"
+#include "SamplingTool.h"
+#include "UStringConcatenate.h"
+#include <wtf/Assertions.h>
+#include <wtf/RefCountedLeakCounter.h>
+#include <wtf/Threading.h>
+
+using namespace WTF;
+
+namespace JSC {
+
+/*
+    Details of the emitBytecode function.
+
+    Return value: The register holding the production's value.
+             dst: An optional parameter specifying the most efficient destination at
+                  which to store the production's value. The callee must honor dst.
+
+    The dst argument provides for a crude form of copy propagation. For example,
+
+        x = 1
+
+    becomes
+    
+        load r[x], 1
+    
+    instead of 
+
+        load r0, 1
+        mov r[x], r0
+    
+    because the assignment node, "x =", passes r[x] as dst to the number node, "1".
+*/
+
+// ------------------------------ ThrowableExpressionData --------------------------------
+
+RegisterID* ThrowableExpressionData::emitThrowReferenceError(BytecodeGenerator& generator, const UString& message)
+{
+    generator.emitExpressionInfo(divot(), startOffset(), endOffset());
+    generator.emitThrowReferenceError(message);
+    return generator.newTemporary();
+}
+
+RegisterID* ThrowableExpressionData::emitThrowSyntaxError(BytecodeGenerator& generator, const UString& message)
+{
+    generator.emitExpressionInfo(divot(), startOffset(), endOffset());
+    generator.emitThrowSyntaxError(message);
+    return generator.newTemporary();
+}
+
+// ------------------------------ NullNode -------------------------------------
+
+RegisterID* NullNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
+{
+    if (dst == generator.ignoredResult())
+        return 0;
+    return generator.emitLoad(dst, jsNull());
+}
+
+// ------------------------------ BooleanNode ----------------------------------
+
+RegisterID* BooleanNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
+{
+    if (dst == generator.ignoredResult())
+        return 0;
+    return generator.emitLoad(dst, m_value);
+}
+
+// ------------------------------ NumberNode -----------------------------------
+
+RegisterID* NumberNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
+{
+    if (dst == generator.ignoredResult())
+        return 0;
+    return generator.emitLoad(dst, m_value);
+}
+
+// ------------------------------ StringNode -----------------------------------
+
+RegisterID* StringNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
+{
+    if (dst == generator.ignoredResult())
+        return 0;
+    return generator.emitLoad(dst, m_value);
+}
+
+// ------------------------------ RegExpNode -----------------------------------
+
+RegisterID* RegExpNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
+{
+    RefPtr<RegExp> regExp = generator.globalData()->regExpCache()->lookupOrCreate(m_pattern.ustring(), m_flags.ustring());
+    if (!regExp->isValid())
+        return emitThrowSyntaxError(generator, makeUString("Invalid regular expression: ", regExp->errorMessage()));
+    if (dst == generator.ignoredResult())
+        return 0;
+    return generator.emitNewRegExp(generator.finalDestination(dst), regExp.get());
+}
+
+// ------------------------------ ThisNode -------------------------------------
+
+RegisterID* ThisNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
+{
+    if (dst == generator.ignoredResult())
+        return 0;
+    return generator.moveToDestinationIfNeeded(dst, generator.thisRegister());
+}
+
+// ------------------------------ ResolveNode ----------------------------------
+
+bool ResolveNode::isPure(BytecodeGenerator& generator) const
+{
+    return generator.isLocal(m_ident);
+}
+
+RegisterID* ResolveNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
+{
+    if (RegisterID* local = generator.registerFor(m_ident)) {
+        if (dst == generator.ignoredResult())
+            return 0;
+        return generator.moveToDestinationIfNeeded(dst, local);
+    }
+    
+    generator.emitExpressionInfo(m_startOffset + m_ident.length(), m_ident.length(), 0);
+    return generator.emitResolve(generator.finalDestination(dst), m_ident);
+}
+
+// ------------------------------ ArrayNode ------------------------------------
+
+RegisterID* ArrayNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
+{
+    // FIXME: Should we put all of this code into emitNewArray?
+
+    unsigned length = 0;
+    ElementNode* firstPutElement;
+    for (firstPutElement = m_element; firstPutElement; firstPutElement = firstPutElement->next()) {
+        if (firstPutElement->elision())
+            break;
+        ++length;
+    }
+
+    if (!firstPutElement && !m_elision)
+        return generator.emitNewArray(generator.finalDestination(dst), m_element);
+
+    RefPtr<RegisterID> array = generator.emitNewArray(generator.tempDestination(dst), m_element);
+
+    for (ElementNode* n = firstPutElement; n; n = n->next()) {
+        RegisterID* value = generator.emitNode(n->value());
+        length += n->elision();
+        generator.emitPutByIndex(array.get(), length++, value);
+    }
+
+    if (m_elision) {
+        RegisterID* value = generator.emitLoad(0, jsNumber(m_elision + length));
+        generator.emitPutById(array.get(), generator.propertyNames().length, value);
+    }
+
+    return generator.moveToDestinationIfNeeded(dst, array.get());
+}
+
+bool ArrayNode::isSimpleArray() const
+{
+    if (m_elision || m_optional)
+        return false;
+    for (ElementNode* ptr = m_element; ptr; ptr = ptr->next()) {
+        if (ptr->elision())
+            return false;
+    }
+    return true;
+}
+
+ArgumentListNode* ArrayNode::toArgumentList(JSGlobalData* globalData) const
+{
+    ASSERT(!m_elision && !m_optional);
+    ElementNode* ptr = m_element;
+    if (!ptr)
+        return 0;
+    ArgumentListNode* head = new (globalData) ArgumentListNode(globalData, ptr->value());
+    ArgumentListNode* tail = head;
+    ptr = ptr->next();
+    for (; ptr; ptr = ptr->next()) {
+        ASSERT(!ptr->elision());
+        tail = new (globalData) ArgumentListNode(globalData, tail, ptr->value());
+    }
+    return head;
+}
+
+// ------------------------------ ObjectLiteralNode ----------------------------
+
+RegisterID* ObjectLiteralNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
+{
+     if (!m_list) {
+         if (dst == generator.ignoredResult())
+             return 0;
+         return generator.emitNewObject(generator.finalDestination(dst));
+     }
+     return generator.emitNode(dst, m_list);
+}
+
+// ------------------------------ PropertyListNode -----------------------------
+
+RegisterID* PropertyListNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
+{
+    RefPtr<RegisterID> newObj = generator.tempDestination(dst);
+    
+    generator.emitNewObject(newObj.get());
+    
+    for (PropertyListNode* p = this; p; p = p->m_next) {
+        RegisterID* value = generator.emitNode(p->m_node->m_assign);
+        
+        switch (p->m_node->m_type) {
+            case PropertyNode::Constant: {
+                generator.emitDirectPutById(newObj.get(), p->m_node->name(), value);
+                break;
+            }
+            case PropertyNode::Getter: {
+                generator.emitPutGetter(newObj.get(), p->m_node->name(), value);
+                break;
+            }
+            case PropertyNode::Setter: {
+                generator.emitPutSetter(newObj.get(), p->m_node->name(), value);
+                break;
+            }
+            default:
+                ASSERT_NOT_REACHED();
+        }
+    }
+    
+    return generator.moveToDestinationIfNeeded(dst, newObj.get());
+}
+
+// ------------------------------ BracketAccessorNode --------------------------------
+
+RegisterID* BracketAccessorNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
+{
+    if (m_base->isResolveNode() && generator.willResolveToArguments(static_cast<ResolveNode*>(m_base)->identifier())) {
+        RegisterID* property = generator.emitNode(m_subscript);
+        generator.emitExpressionInfo(divot(), startOffset(), endOffset());    
+        return generator.emitGetArgumentByVal(generator.finalDestination(dst), generator.uncheckedRegisterForArguments(), property);
+    }
+
+    RefPtr<RegisterID> base = generator.emitNodeForLeftHandSide(m_base, m_subscriptHasAssignments, m_subscript->isPure(generator));
+    RegisterID* property = generator.emitNode(m_subscript);
+    generator.emitExpressionInfo(divot(), startOffset(), endOffset());
+    return generator.emitGetByVal(generator.finalDestination(dst), base.get(), property);
+}
+
+// ------------------------------ DotAccessorNode --------------------------------
+
+RegisterID* DotAccessorNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
+{
+    if (m_ident == generator.propertyNames().length) {
+        if (!m_base->isResolveNode())
+            goto nonArgumentsPath;
+        ResolveNode* resolveNode = static_cast<ResolveNode*>(m_base);
+        if (!generator.willResolveToArguments(resolveNode->identifier()))
+            goto nonArgumentsPath;
+        generator.emitExpressionInfo(divot(), startOffset(), endOffset());    
+        return generator.emitGetArgumentsLength(generator.finalDestination(dst), generator.uncheckedRegisterForArguments());
+    }
+
+nonArgumentsPath:
+    RegisterID* base = generator.emitNode(m_base);
+    generator.emitExpressionInfo(divot(), startOffset(), endOffset());
+    return generator.emitGetById(generator.finalDestination(dst), base, m_ident);
+}
+
+// ------------------------------ ArgumentListNode -----------------------------
+
+RegisterID* ArgumentListNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
+{
+    ASSERT(m_expr);
+    return generator.emitNode(dst, m_expr);
+}
+
+// ------------------------------ NewExprNode ----------------------------------
+
+RegisterID* NewExprNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
+{
+    RefPtr<RegisterID> func = generator.emitNode(m_expr);
+    CallArguments callArguments(generator, m_args);
+    return generator.emitConstruct(generator.finalDestinationOrIgnored(dst), func.get(), callArguments, divot(), startOffset(), endOffset());
+}
+
+CallArguments::CallArguments(BytecodeGenerator& generator, ArgumentsNode* argumentsNode)
+    : m_argumentsNode(argumentsNode)
+{
+    if (generator.shouldEmitProfileHooks())
+        m_profileHookRegister = generator.newTemporary();
+    m_argv.append(generator.newTemporary());
+    if (argumentsNode) {
+        for (ArgumentListNode* n = argumentsNode->m_listNode; n; n = n->m_next) {
+            m_argv.append(generator.newTemporary());
+            // op_call requires the arguments to be a sequential range of registers
+            ASSERT(m_argv[m_argv.size() - 1]->index() == m_argv[m_argv.size() - 2]->index() + 1);
+        }
+    }
+}
+
+// ------------------------------ EvalFunctionCallNode ----------------------------------
+
+RegisterID* EvalFunctionCallNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
+{
+    RefPtr<RegisterID> func = generator.tempDestination(dst);
+    CallArguments callArguments(generator, m_args);
+    generator.emitExpressionInfo(divot() - startOffset() + 4, 4, 0);
+    generator.emitResolveWithBase(callArguments.thisRegister(), func.get(), generator.propertyNames().eval);
+    return generator.emitCallEval(generator.finalDestination(dst, func.get()), func.get(), callArguments, divot(), startOffset(), endOffset());
+}
+
+// ------------------------------ FunctionCallValueNode ----------------------------------
+
+RegisterID* FunctionCallValueNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
+{
+    RefPtr<RegisterID> func = generator.emitNode(m_expr);
+    CallArguments callArguments(generator, m_args);
+    generator.emitLoad(callArguments.thisRegister(), jsUndefined());
+    return generator.emitCall(generator.finalDestinationOrIgnored(dst, func.get()), func.get(), callArguments, divot(), startOffset(), endOffset());
+}
+
+// ------------------------------ FunctionCallResolveNode ----------------------------------
+
+RegisterID* FunctionCallResolveNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
+{
+    if (RefPtr<RegisterID> local = generator.registerFor(m_ident)) {
+        CallArguments callArguments(generator, m_args);
+        generator.emitLoad(callArguments.thisRegister(), jsUndefined());
+        return generator.emitCall(generator.finalDestinationOrIgnored(dst, callArguments.thisRegister()), local.get(), callArguments, divot(), startOffset(), endOffset());
+    }
+
+    int index = 0;
+    size_t depth = 0;
+    JSObject* globalObject = 0;
+    bool requiresDynamicChecks = false;
+    if (generator.findScopedProperty(m_ident, index, depth, false, requiresDynamicChecks, globalObject) && index != missingSymbolMarker() && !requiresDynamicChecks) {
+        RefPtr<RegisterID> func = generator.emitGetScopedVar(generator.newTemporary(), depth, index, globalObject);
+        CallArguments callArguments(generator, m_args);
+        generator.emitLoad(callArguments.thisRegister(), jsUndefined());
+        return generator.emitCall(generator.finalDestinationOrIgnored(dst, func.get()), func.get(), callArguments, divot(), startOffset(), endOffset());
+    }
+
+    RefPtr<RegisterID> func = generator.newTemporary();
+    CallArguments callArguments(generator, m_args);
+    int identifierStart = divot() - startOffset();
+    generator.emitExpressionInfo(identifierStart + m_ident.length(), m_ident.length(), 0);
+    generator.emitResolveWithBase(callArguments.thisRegister(), func.get(), m_ident);
+    return generator.emitCall(generator.finalDestinationOrIgnored(dst, func.get()), func.get(), callArguments, divot(), startOffset(), endOffset());
+}
+
+// ------------------------------ FunctionCallBracketNode ----------------------------------
+
+RegisterID* FunctionCallBracketNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
+{
+    RefPtr<RegisterID> base = generator.emitNode(m_base);
+    RegisterID* property = generator.emitNode(m_subscript);
+    generator.emitExpressionInfo(divot() - m_subexpressionDivotOffset, startOffset() - m_subexpressionDivotOffset, m_subexpressionEndOffset);
+    RefPtr<RegisterID> function = generator.emitGetByVal(generator.tempDestination(dst), base.get(), property);
+    CallArguments callArguments(generator, m_args);
+    generator.emitMove(callArguments.thisRegister(), base.get());
+    return generator.emitCall(generator.finalDestinationOrIgnored(dst, function.get()), function.get(), callArguments, divot(), startOffset(), endOffset());
+}
+
+// ------------------------------ FunctionCallDotNode ----------------------------------
+
+RegisterID* FunctionCallDotNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
+{
+    RefPtr<RegisterID> function = generator.tempDestination(dst);
+    CallArguments callArguments(generator, m_args);
+    generator.emitNode(callArguments.thisRegister(), m_base);
+    generator.emitExpressionInfo(divot() - m_subexpressionDivotOffset, startOffset() - m_subexpressionDivotOffset, m_subexpressionEndOffset);
+    generator.emitMethodCheck();
+    generator.emitGetById(function.get(), callArguments.thisRegister(), m_ident);
+    return generator.emitCall(generator.finalDestinationOrIgnored(dst, function.get()), function.get(), callArguments, divot(), startOffset(), endOffset());
+}
+
+RegisterID* CallFunctionCallDotNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
+{
+    RefPtr<Label> realCall = generator.newLabel();
+    RefPtr<Label> end = generator.newLabel();
+    RefPtr<RegisterID> base = generator.emitNode(m_base);
+    generator.emitExpressionInfo(divot() - m_subexpressionDivotOffset, startOffset() - m_subexpressionDivotOffset, m_subexpressionEndOffset);
+    RefPtr<RegisterID> function = generator.emitGetById(generator.tempDestination(dst), base.get(), m_ident);
+    RefPtr<RegisterID> finalDestinationOrIgnored = generator.finalDestinationOrIgnored(dst, function.get());
+    generator.emitJumpIfNotFunctionCall(function.get(), realCall.get());
+    {
+        if (m_args->m_listNode && m_args->m_listNode->m_expr) {
+            ArgumentListNode* oldList = m_args->m_listNode;
+            m_args->m_listNode = m_args->m_listNode->m_next;
+
+            RefPtr<RegisterID> realFunction = generator.emitMove(generator.tempDestination(dst), base.get());
+            CallArguments callArguments(generator, m_args);
+            generator.emitNode(callArguments.thisRegister(), oldList->m_expr);
+            generator.emitCall(finalDestinationOrIgnored.get(), realFunction.get(), callArguments, divot(), startOffset(), endOffset());
+            generator.emitJump(end.get());
+
+            m_args->m_listNode = oldList;
+
+        } else {
+            RefPtr<RegisterID> realFunction = generator.emitMove(generator.tempDestination(dst), base.get());
+            CallArguments callArguments(generator, m_args);
+            generator.emitLoad(callArguments.thisRegister(), jsUndefined());
+            generator.emitCall(finalDestinationOrIgnored.get(), realFunction.get(), callArguments, divot(), startOffset(), endOffset());
+            generator.emitJump(end.get());
+        }
+    }
+    generator.emitLabel(realCall.get());
+    {
+        CallArguments callArguments(generator, m_args);
+        generator.emitMove(callArguments.thisRegister(), base.get());
+        generator.emitCall(finalDestinationOrIgnored.get(), function.get(), callArguments, divot(), startOffset(), endOffset());
+    }
+    generator.emitLabel(end.get());
+    return finalDestinationOrIgnored.get();
+}
+
+static bool areTrivialApplyArguments(ArgumentsNode* args)
+{
+    return !args->m_listNode || !args->m_listNode->m_expr || !args->m_listNode->m_next
+        || (!args->m_listNode->m_next->m_next && args->m_listNode->m_next->m_expr->isSimpleArray());
+}
+
+RegisterID* ApplyFunctionCallDotNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
+{
+    // A few simple cases can be trivially handled as ordinary function calls.
+    // function.apply(), function.apply(arg) -> identical to function.call
+    // function.apply(thisArg, [arg0, arg1, ...]) -> can be trivially coerced into function.call(thisArg, arg0, arg1, ...) and saves object allocation
+    bool mayBeCall = areTrivialApplyArguments(m_args);
+
+    RefPtr<Label> realCall = generator.newLabel();
+    RefPtr<Label> end = generator.newLabel();
+    RefPtr<RegisterID> base = generator.emitNode(m_base);
+    generator.emitExpressionInfo(divot() - m_subexpressionDivotOffset, startOffset() - m_subexpressionDivotOffset, m_subexpressionEndOffset);
+    RefPtr<RegisterID> function = generator.emitGetById(generator.tempDestination(dst), base.get(), m_ident);
+    RefPtr<RegisterID> finalDestinationOrIgnored = generator.finalDestinationOrIgnored(dst, function.get());
+    generator.emitJumpIfNotFunctionApply(function.get(), realCall.get());
+    {
+        if (mayBeCall) {
+            if (m_args->m_listNode && m_args->m_listNode->m_expr) {
+                ArgumentListNode* oldList = m_args->m_listNode;
+                if (m_args->m_listNode->m_next) {
+                    ASSERT(m_args->m_listNode->m_next->m_expr->isSimpleArray());
+                    ASSERT(!m_args->m_listNode->m_next->m_next);
+                    m_args->m_listNode = static_cast<ArrayNode*>(m_args->m_listNode->m_next->m_expr)->toArgumentList(generator.globalData());
+                    RefPtr<RegisterID> realFunction = generator.emitMove(generator.tempDestination(dst), base.get());
+                    CallArguments callArguments(generator, m_args);
+                    generator.emitNode(callArguments.thisRegister(), oldList->m_expr);
+                    generator.emitCall(finalDestinationOrIgnored.get(), realFunction.get(), callArguments, divot(), startOffset(), endOffset());
+                } else {
+                    m_args->m_listNode = m_args->m_listNode->m_next;
+                    RefPtr<RegisterID> realFunction = generator.emitMove(generator.tempDestination(dst), base.get());
+                    CallArguments callArguments(generator, m_args);
+                    generator.emitNode(callArguments.thisRegister(), oldList->m_expr);
+                    generator.emitCall(finalDestinationOrIgnored.get(), realFunction.get(), callArguments, divot(), startOffset(), endOffset());
+                }
+                m_args->m_listNode = oldList;
+            } else {
+                RefPtr<RegisterID> realFunction = generator.emitMove(generator.tempDestination(dst), base.get());
+                CallArguments callArguments(generator, m_args);
+                generator.emitLoad(callArguments.thisRegister(), jsUndefined());
+                generator.emitCall(finalDestinationOrIgnored.get(), realFunction.get(), callArguments, divot(), startOffset(), endOffset());
+            }
+        } else {
+            ASSERT(m_args->m_listNode && m_args->m_listNode->m_next);
+            RefPtr<RegisterID> realFunction = generator.emitMove(generator.newTemporary(), base.get());
+            RefPtr<RegisterID> argsCountRegister = generator.newTemporary();
+            RefPtr<RegisterID> thisRegister = generator.newTemporary();
+            RefPtr<RegisterID> argsRegister = generator.newTemporary();
+            generator.emitNode(thisRegister.get(), m_args->m_listNode->m_expr);
+            ArgumentListNode* args = m_args->m_listNode->m_next;
+            bool isArgumentsApply = false;
+            if (args->m_expr->isResolveNode()) {
+                ResolveNode* resolveNode = static_cast<ResolveNode*>(args->m_expr);
+                isArgumentsApply = generator.willResolveToArguments(resolveNode->identifier());
+                if (isArgumentsApply)
+                    generator.emitMove(argsRegister.get(), generator.uncheckedRegisterForArguments());
+            }
+            if (!isArgumentsApply)
+                generator.emitNode(argsRegister.get(), args->m_expr);
+            while ((args = args->m_next))
+                generator.emitNode(args->m_expr);
+
+            generator.emitLoadVarargs(argsCountRegister.get(), thisRegister.get(), argsRegister.get());
+            generator.emitCallVarargs(finalDestinationOrIgnored.get(), realFunction.get(), thisRegister.get(), argsCountRegister.get(), divot(), startOffset(), endOffset());
+        }
+        generator.emitJump(end.get());
+    }
+    generator.emitLabel(realCall.get());
+    {
+        CallArguments callArguments(generator, m_args);
+        generator.emitMove(callArguments.thisRegister(), base.get());
+        generator.emitCall(finalDestinationOrIgnored.get(), function.get(), callArguments, divot(), startOffset(), endOffset());
+    }
+    generator.emitLabel(end.get());
+    return finalDestinationOrIgnored.get();
+}
+
+// ------------------------------ PostfixResolveNode ----------------------------------
+
+static RegisterID* emitPreIncOrDec(BytecodeGenerator& generator, RegisterID* srcDst, Operator oper)
+{
+    return (oper == OpPlusPlus) ? generator.emitPreInc(srcDst) : generator.emitPreDec(srcDst);
+}
+
+static RegisterID* emitPostIncOrDec(BytecodeGenerator& generator, RegisterID* dst, RegisterID* srcDst, Operator oper)
+{
+    if (srcDst == dst)
+        return generator.emitToJSNumber(dst, srcDst);
+    return (oper == OpPlusPlus) ? generator.emitPostInc(dst, srcDst) : generator.emitPostDec(dst, srcDst);
+}
+
+RegisterID* PostfixResolveNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
+{
+    if (RegisterID* local = generator.registerFor(m_ident)) {
+        if (generator.isLocalConstant(m_ident)) {
+            if (dst == generator.ignoredResult())
+                return 0;
+            return generator.emitToJSNumber(generator.finalDestination(dst), local);
+        }
+
+        if (dst == generator.ignoredResult())
+            return emitPreIncOrDec(generator, local, m_operator);
+        return emitPostIncOrDec(generator, generator.finalDestination(dst), local, m_operator);
+    }
+
+    int index = 0;
+    size_t depth = 0;
+    JSObject* globalObject = 0;
+    bool requiresDynamicChecks = false;
+    if (generator.findScopedProperty(m_ident, index, depth, true, requiresDynamicChecks, globalObject) && index != missingSymbolMarker() && !requiresDynamicChecks) {
+        RefPtr<RegisterID> value = generator.emitGetScopedVar(generator.newTemporary(), depth, index, globalObject);
+        RegisterID* oldValue;
+        if (dst == generator.ignoredResult()) {
+            oldValue = 0;
+            emitPreIncOrDec(generator, value.get(), m_operator);
+        } else {
+            oldValue = emitPostIncOrDec(generator, generator.finalDestination(dst), value.get(), m_operator);
+        }
+        generator.emitPutScopedVar(depth, index, value.get(), globalObject);
+        return oldValue;
+    }
+
+    generator.emitExpressionInfo(divot(), startOffset(), endOffset());
+    RefPtr<RegisterID> value = generator.newTemporary();
+    RefPtr<RegisterID> base = generator.emitResolveWithBase(generator.newTemporary(), value.get(), m_ident);
+    RegisterID* oldValue;
+    if (dst == generator.ignoredResult()) {
+        oldValue = 0;
+        emitPreIncOrDec(generator, value.get(), m_operator);
+    } else {
+        oldValue = emitPostIncOrDec(generator, generator.finalDestination(dst), value.get(), m_operator);
+    }
+    generator.emitPutById(base.get(), m_ident, value.get());
+    return oldValue;
+}
+
+// ------------------------------ PostfixBracketNode ----------------------------------
+
+RegisterID* PostfixBracketNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
+{
+    RefPtr<RegisterID> base = generator.emitNode(m_base);
+    RefPtr<RegisterID> property = generator.emitNode(m_subscript);
+
+    generator.emitExpressionInfo(divot() - m_subexpressionDivotOffset, startOffset() - m_subexpressionDivotOffset, m_subexpressionEndOffset);
+    RefPtr<RegisterID> value = generator.emitGetByVal(generator.newTemporary(), base.get(), property.get());
+    RegisterID* oldValue;
+    if (dst == generator.ignoredResult()) {
+        oldValue = 0;
+        if (m_operator == OpPlusPlus)
+            generator.emitPreInc(value.get());
+        else
+            generator.emitPreDec(value.get());
+    } else {
+        oldValue = (m_operator == OpPlusPlus) ? generator.emitPostInc(generator.finalDestination(dst), value.get()) : generator.emitPostDec(generator.finalDestination(dst), value.get());
+    }
+    generator.emitExpressionInfo(divot(), startOffset(), endOffset());
+    generator.emitPutByVal(base.get(), property.get(), value.get());
+    return oldValue;
+}
+
+// ------------------------------ PostfixDotNode ----------------------------------
+
+RegisterID* PostfixDotNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
+{
+    RefPtr<RegisterID> base = generator.emitNode(m_base);
+
+    generator.emitExpressionInfo(divot() - m_subexpressionDivotOffset, startOffset() - m_subexpressionDivotOffset, m_subexpressionEndOffset);
+    RefPtr<RegisterID> value = generator.emitGetById(generator.newTemporary(), base.get(), m_ident);
+    RegisterID* oldValue;
+    if (dst == generator.ignoredResult()) {
+        oldValue = 0;
+        if (m_operator == OpPlusPlus)
+            generator.emitPreInc(value.get());
+        else
+            generator.emitPreDec(value.get());
+    } else {
+        oldValue = (m_operator == OpPlusPlus) ? generator.emitPostInc(generator.finalDestination(dst), value.get()) : generator.emitPostDec(generator.finalDestination(dst), value.get());
+    }
+    generator.emitExpressionInfo(divot(), startOffset(), endOffset());
+    generator.emitPutById(base.get(), m_ident, value.get());
+    return oldValue;
+}
+
+// ------------------------------ PostfixErrorNode -----------------------------------
+
+RegisterID* PostfixErrorNode::emitBytecode(BytecodeGenerator& generator, RegisterID*)
+{
+    return emitThrowReferenceError(generator, m_operator == OpPlusPlus
+        ? "Postfix ++ operator applied to value that is not a reference."
+        : "Postfix -- operator applied to value that is not a reference.");
+}
+
+// ------------------------------ DeleteResolveNode -----------------------------------
+
+RegisterID* DeleteResolveNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
+{
+    if (generator.registerFor(m_ident))
+        return generator.emitLoad(generator.finalDestination(dst), false);
+
+    generator.emitExpressionInfo(divot(), startOffset(), endOffset());
+    RegisterID* base = generator.emitResolveBase(generator.tempDestination(dst), m_ident);
+    return generator.emitDeleteById(generator.finalDestination(dst, base), base, m_ident);
+}
+
+// ------------------------------ DeleteBracketNode -----------------------------------
+
+RegisterID* DeleteBracketNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
+{
+    RefPtr<RegisterID> r0 = generator.emitNode(m_base);
+    RegisterID* r1 = generator.emitNode(m_subscript);
+
+    generator.emitExpressionInfo(divot(), startOffset(), endOffset());
+    return generator.emitDeleteByVal(generator.finalDestination(dst), r0.get(), r1);
+}
+
+// ------------------------------ DeleteDotNode -----------------------------------
+
+RegisterID* DeleteDotNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
+{
+    RegisterID* r0 = generator.emitNode(m_base);
+
+    generator.emitExpressionInfo(divot(), startOffset(), endOffset());
+    return generator.emitDeleteById(generator.finalDestination(dst), r0, m_ident);
+}
+
+// ------------------------------ DeleteValueNode -----------------------------------
+
+RegisterID* DeleteValueNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
+{
+    generator.emitNode(generator.ignoredResult(), m_expr);
+
+    // delete on a non-location expression ignores the value and returns true
+    return generator.emitLoad(generator.finalDestination(dst), true);
+}
+
+// ------------------------------ VoidNode -------------------------------------
+
+RegisterID* VoidNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
+{
+    if (dst == generator.ignoredResult()) {
+        generator.emitNode(generator.ignoredResult(), m_expr);
+        return 0;
+    }
+    RefPtr<RegisterID> r0 = generator.emitNode(m_expr);
+    return generator.emitLoad(dst, jsUndefined());
+}
+
+// ------------------------------ TypeOfValueNode -----------------------------------
+
+RegisterID* TypeOfResolveNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
+{
+    if (RegisterID* local = generator.registerFor(m_ident)) {
+        if (dst == generator.ignoredResult())
+            return 0;
+        return generator.emitTypeOf(generator.finalDestination(dst), local);
+    }
+
+    RefPtr<RegisterID> scratch = generator.emitResolveBase(generator.tempDestination(dst), m_ident);
+    generator.emitGetById(scratch.get(), scratch.get(), m_ident);
+    if (dst == generator.ignoredResult())
+        return 0;
+    return generator.emitTypeOf(generator.finalDestination(dst, scratch.get()), scratch.get());
+}
+
+// ------------------------------ TypeOfValueNode -----------------------------------
+
+RegisterID* TypeOfValueNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
+{
+    if (dst == generator.ignoredResult()) {
+        generator.emitNode(generator.ignoredResult(), m_expr);
+        return 0;
+    }
+    RefPtr<RegisterID> src = generator.emitNode(m_expr);
+    return generator.emitTypeOf(generator.finalDestination(dst), src.get());
+}
+
+// ------------------------------ PrefixResolveNode ----------------------------------
+
+RegisterID* PrefixResolveNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
+{
+    if (RegisterID* local = generator.registerFor(m_ident)) {
+        if (generator.isLocalConstant(m_ident)) {
+            if (dst == generator.ignoredResult())
+                return 0;
+            RefPtr<RegisterID> r0 = generator.emitLoad(generator.finalDestination(dst), (m_operator == OpPlusPlus) ? 1.0 : -1.0);
+            return generator.emitBinaryOp(op_add, r0.get(), local, r0.get(), OperandTypes());
+        }
+
+        emitPreIncOrDec(generator, local, m_operator);
+        return generator.moveToDestinationIfNeeded(dst, local);
+    }
+
+    int index = 0;
+    size_t depth = 0;
+    JSObject* globalObject = 0;
+    bool requiresDynamicChecks = false;
+    if (generator.findScopedProperty(m_ident, index, depth, false, requiresDynamicChecks, globalObject) && index != missingSymbolMarker() && !requiresDynamicChecks) {
+        RefPtr<RegisterID> propDst = generator.emitGetScopedVar(generator.tempDestination(dst), depth, index, globalObject);
+        emitPreIncOrDec(generator, propDst.get(), m_operator);
+        generator.emitPutScopedVar(depth, index, propDst.get(), globalObject);
+        return generator.moveToDestinationIfNeeded(dst, propDst.get());
+    }
+
+    generator.emitExpressionInfo(divot(), startOffset(), endOffset());
+    RefPtr<RegisterID> propDst = generator.tempDestination(dst);
+    RefPtr<RegisterID> base = generator.emitResolveWithBase(generator.newTemporary(), propDst.get(), m_ident);
+    emitPreIncOrDec(generator, propDst.get(), m_operator);
+    generator.emitPutById(base.get(), m_ident, propDst.get());
+    return generator.moveToDestinationIfNeeded(dst, propDst.get());
+}
+
+// ------------------------------ PrefixBracketNode ----------------------------------
+
+RegisterID* PrefixBracketNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
+{
+    RefPtr<RegisterID> base = generator.emitNode(m_base);
+    RefPtr<RegisterID> property = generator.emitNode(m_subscript);
+    RefPtr<RegisterID> propDst = generator.tempDestination(dst);
+
+    generator.emitExpressionInfo(divot() + m_subexpressionDivotOffset, m_subexpressionStartOffset, endOffset() - m_subexpressionDivotOffset);
+    RegisterID* value = generator.emitGetByVal(propDst.get(), base.get(), property.get());
+    if (m_operator == OpPlusPlus)
+        generator.emitPreInc(value);
+    else
+        generator.emitPreDec(value);
+    generator.emitExpressionInfo(divot(), startOffset(), endOffset());
+    generator.emitPutByVal(base.get(), property.get(), value);
+    return generator.moveToDestinationIfNeeded(dst, propDst.get());
+}
+
+// ------------------------------ PrefixDotNode ----------------------------------
+
+RegisterID* PrefixDotNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
+{
+    RefPtr<RegisterID> base = generator.emitNode(m_base);
+    RefPtr<RegisterID> propDst = generator.tempDestination(dst);
+
+    generator.emitExpressionInfo(divot() + m_subexpressionDivotOffset, m_subexpressionStartOffset, endOffset() - m_subexpressionDivotOffset);
+    RegisterID* value = generator.emitGetById(propDst.get(), base.get(), m_ident);
+    if (m_operator == OpPlusPlus)
+        generator.emitPreInc(value);
+    else
+        generator.emitPreDec(value);
+    generator.emitExpressionInfo(divot(), startOffset(), endOffset());
+    generator.emitPutById(base.get(), m_ident, value);
+    return generator.moveToDestinationIfNeeded(dst, propDst.get());
+}
+
+// ------------------------------ PrefixErrorNode -----------------------------------
+
+RegisterID* PrefixErrorNode::emitBytecode(BytecodeGenerator& generator, RegisterID*)
+{
+    return emitThrowReferenceError(generator, m_operator == OpPlusPlus
+        ? "Prefix ++ operator applied to value that is not a reference."
+        : "Prefix -- operator applied to value that is not a reference.");
+}
+
+// ------------------------------ Unary Operation Nodes -----------------------------------
+
+RegisterID* UnaryOpNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
+{
+    RegisterID* src = generator.emitNode(m_expr);
+    return generator.emitUnaryOp(opcodeID(), generator.finalDestination(dst), src);
+}
+
+
+// ------------------------------ LogicalNotNode -----------------------------------
+
+void LogicalNotNode::emitBytecodeInConditionContext(BytecodeGenerator& generator, Label* trueTarget, Label* falseTarget, bool fallThroughMeansTrue)
+{
+    ASSERT(expr()->hasConditionContextCodegen());
+
+    // reverse the true and false targets
+    generator.emitNodeInConditionContext(expr(), falseTarget, trueTarget, !fallThroughMeansTrue);
+}
+
+
+// ------------------------------ Binary Operation Nodes -----------------------------------
+
+// BinaryOpNode::emitStrcat:
+//
+// This node generates an op_strcat operation.  This opcode can handle concatenation of three or
+// more values, where we can determine a set of separate op_add operations would be operating on
+// string values.
+//
+// This function expects to be operating on a graph of AST nodes looking something like this:
+//
+//     (a)...     (b)
+//          \   /
+//           (+)     (c)
+//              \   /
+//      [d]     ((+))
+//         \    /
+//          [+=]
+//
+// The assignment operation is optional, if it exists the register holding the value on the
+// lefthand side of the assignment should be passing as the optional 'lhs' argument.
+//
+// The method should be called on the node at the root of the tree of regular binary add
+// operations (marked in the diagram with a double set of parentheses).  This node must
+// be performing a string concatenation (determined by statically detecting that at least
+// one child must be a string).  
+//
+// Since the minimum number of values being concatenated together is expected to be 3, if
+// a lhs to a concatenating assignment is not provided then the  root add should have at
+// least one left child that is also an add that can be determined to be operating on strings.
+//
+RegisterID* BinaryOpNode::emitStrcat(BytecodeGenerator& generator, RegisterID* dst, RegisterID* lhs, ReadModifyResolveNode* emitExpressionInfoForMe)
+{
+    ASSERT(isAdd());
+    ASSERT(resultDescriptor().definitelyIsString());
+
+    // Create a list of expressions for all the adds in the tree of nodes we can convert into
+    // a string concatenation.  The rightmost node (c) is added first.  The rightmost node is
+    // added first, and the leftmost child is never added, so the vector produced for the
+    // example above will be [ c, b ].
+    Vector<ExpressionNode*, 16> reverseExpressionList;
+    reverseExpressionList.append(m_expr2);
+
+    // Examine the left child of the add.  So long as this is a string add, add its right-child
+    // to the list, and keep processing along the left fork.
+    ExpressionNode* leftMostAddChild = m_expr1;
+    while (leftMostAddChild->isAdd() && leftMostAddChild->resultDescriptor().definitelyIsString()) {
+        reverseExpressionList.append(static_cast<AddNode*>(leftMostAddChild)->m_expr2);
+        leftMostAddChild = static_cast<AddNode*>(leftMostAddChild)->m_expr1;
+    }
+
+    Vector<RefPtr<RegisterID>, 16> temporaryRegisters;
+
+    // If there is an assignment, allocate a temporary to hold the lhs after conversion.
+    // We could possibly avoid this (the lhs is converted last anyway, we could let the
+    // op_strcat node handle its conversion if required).
+    if (lhs)
+        temporaryRegisters.append(generator.newTemporary());
+
+    // Emit code for the leftmost node ((a) in the example).
+    temporaryRegisters.append(generator.newTemporary());
+    RegisterID* leftMostAddChildTempRegister = temporaryRegisters.last().get();
+    generator.emitNode(leftMostAddChildTempRegister, leftMostAddChild);
+
+    // Note on ordering of conversions:
+    //
+    // We maintain the same ordering of conversions as we would see if the concatenations
+    // was performed as a sequence of adds (otherwise this optimization could change
+    // behaviour should an object have been provided a valueOf or toString method).
+    //
+    // Considering the above example, the sequnce of execution is:
+    //     * evaluate operand (a)
+    //     * evaluate operand (b)
+    //     * convert (a) to primitive   <-  (this would be triggered by the first add)
+    //     * convert (b) to primitive   <-  (ditto)
+    //     * evaluate operand (c)
+    //     * convert (c) to primitive   <-  (this would be triggered by the second add)
+    // And optionally, if there is an assignment:
+    //     * convert (d) to primitive   <-  (this would be triggered by the assigning addition)
+    //
+    // As such we do not plant an op to convert the leftmost child now.  Instead, use
+    // 'leftMostAddChildTempRegister' as a flag to trigger generation of the conversion
+    // once the second node has been generated.  However, if the leftmost child is an
+    // immediate we can trivially determine that no conversion will be required.
+    // If this is the case
+    if (leftMostAddChild->isString())
+        leftMostAddChildTempRegister = 0;
+
+    while (reverseExpressionList.size()) {
+        ExpressionNode* node = reverseExpressionList.last();
+        reverseExpressionList.removeLast();
+
+        // Emit the code for the current node.
+        temporaryRegisters.append(generator.newTemporary());
+        generator.emitNode(temporaryRegisters.last().get(), node);
+
+        // On the first iteration of this loop, when we first reach this point we have just
+        // generated the second node, which means it is time to convert the leftmost operand.
+        if (leftMostAddChildTempRegister) {
+            generator.emitToPrimitive(leftMostAddChildTempRegister, leftMostAddChildTempRegister);
+            leftMostAddChildTempRegister = 0; // Only do this once.
+        }
+        // Plant a conversion for this node, if necessary.
+        if (!node->isString())
+            generator.emitToPrimitive(temporaryRegisters.last().get(), temporaryRegisters.last().get());
+    }
+    ASSERT(temporaryRegisters.size() >= 3);
+
+    // Certain read-modify nodes require expression info to be emitted *after* m_right has been generated.
+    // If this is required the node is passed as 'emitExpressionInfoForMe'; do so now.
+    if (emitExpressionInfoForMe)
+        generator.emitExpressionInfo(emitExpressionInfoForMe->divot(), emitExpressionInfoForMe->startOffset(), emitExpressionInfoForMe->endOffset());
+
+    // If there is an assignment convert the lhs now.  This will also copy lhs to
+    // the temporary register we allocated for it.
+    if (lhs)
+        generator.emitToPrimitive(temporaryRegisters[0].get(), lhs);
+
+    return generator.emitStrcat(generator.finalDestination(dst, temporaryRegisters[0].get()), temporaryRegisters[0].get(), temporaryRegisters.size());
+}
+
+RegisterID* BinaryOpNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
+{
+    OpcodeID opcodeID = this->opcodeID();
+
+    if (opcodeID == op_add && m_expr1->isAdd() && m_expr1->resultDescriptor().definitelyIsString())
+        return emitStrcat(generator, dst);
+
+    if (opcodeID == op_neq) {
+        if (m_expr1->isNull() || m_expr2->isNull()) {
+            RefPtr<RegisterID> src = generator.tempDestination(dst);
+            generator.emitNode(src.get(), m_expr1->isNull() ? m_expr2 : m_expr1);
+            return generator.emitUnaryOp(op_neq_null, generator.finalDestination(dst, src.get()), src.get());
+        }
+    }
+
+    RefPtr<RegisterID> src1 = generator.emitNodeForLeftHandSide(m_expr1, m_rightHasAssignments, m_expr2->isPure(generator));
+    RegisterID* src2 = generator.emitNode(m_expr2);
+    return generator.emitBinaryOp(opcodeID, generator.finalDestination(dst, src1.get()), src1.get(), src2, OperandTypes(m_expr1->resultDescriptor(), m_expr2->resultDescriptor()));
+}
+
+RegisterID* EqualNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
+{
+    if (m_expr1->isNull() || m_expr2->isNull()) {
+        RefPtr<RegisterID> src = generator.tempDestination(dst);
+        generator.emitNode(src.get(), m_expr1->isNull() ? m_expr2 : m_expr1);
+        return generator.emitUnaryOp(op_eq_null, generator.finalDestination(dst, src.get()), src.get());
+    }
+
+    RefPtr<RegisterID> src1 = generator.emitNodeForLeftHandSide(m_expr1, m_rightHasAssignments, m_expr2->isPure(generator));
+    RegisterID* src2 = generator.emitNode(m_expr2);
+    return generator.emitEqualityOp(op_eq, generator.finalDestination(dst, src1.get()), src1.get(), src2);
+}
+
+RegisterID* StrictEqualNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
+{
+    RefPtr<RegisterID> src1 = generator.emitNodeForLeftHandSide(m_expr1, m_rightHasAssignments, m_expr2->isPure(generator));
+    RegisterID* src2 = generator.emitNode(m_expr2);
+    return generator.emitEqualityOp(op_stricteq, generator.finalDestination(dst, src1.get()), src1.get(), src2);
+}
+
+RegisterID* ReverseBinaryOpNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
+{
+    RefPtr<RegisterID> src1 = generator.emitNodeForLeftHandSide(m_expr1, m_rightHasAssignments, m_expr2->isPure(generator));
+    RegisterID* src2 = generator.emitNode(m_expr2);
+    return generator.emitBinaryOp(opcodeID(), generator.finalDestination(dst, src1.get()), src2, src1.get(), OperandTypes(m_expr2->resultDescriptor(), m_expr1->resultDescriptor()));
+}
+
+RegisterID* ThrowableBinaryOpNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
+{
+    RefPtr<RegisterID> src1 = generator.emitNodeForLeftHandSide(m_expr1, m_rightHasAssignments, m_expr2->isPure(generator));
+    RegisterID* src2 = generator.emitNode(m_expr2);
+    generator.emitExpressionInfo(divot(), startOffset(), endOffset());
+    return generator.emitBinaryOp(opcodeID(), generator.finalDestination(dst, src1.get()), src1.get(), src2, OperandTypes(m_expr1->resultDescriptor(), m_expr2->resultDescriptor()));
+}
+
+RegisterID* InstanceOfNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
+{
+    RefPtr<RegisterID> src1 = generator.emitNodeForLeftHandSide(m_expr1, m_rightHasAssignments, m_expr2->isPure(generator));
+    RefPtr<RegisterID> src2 = generator.emitNode(m_expr2);
+
+    generator.emitExpressionInfo(divot(), startOffset(), endOffset());
+    generator.emitCheckHasInstance(src2.get());
+
+    generator.emitExpressionInfo(divot(), startOffset(), endOffset());
+    RegisterID* src2Prototype = generator.emitGetById(generator.newTemporary(), src2.get(), generator.globalData()->propertyNames->prototype);
+
+    generator.emitExpressionInfo(divot(), startOffset(), endOffset());
+    return generator.emitInstanceOf(generator.finalDestination(dst, src1.get()), src1.get(), src2.get(), src2Prototype);
+}
+
+// ------------------------------ LogicalOpNode ----------------------------
+
+RegisterID* LogicalOpNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
+{
+    RefPtr<RegisterID> temp = generator.tempDestination(dst);
+    RefPtr<Label> target = generator.newLabel();
+    
+    generator.emitNode(temp.get(), m_expr1);
+    if (m_operator == OpLogicalAnd)
+        generator.emitJumpIfFalse(temp.get(), target.get());
+    else
+        generator.emitJumpIfTrue(temp.get(), target.get());
+    generator.emitNode(temp.get(), m_expr2);
+    generator.emitLabel(target.get());
+
+    return generator.moveToDestinationIfNeeded(dst, temp.get());
+}
+
+void LogicalOpNode::emitBytecodeInConditionContext(BytecodeGenerator& generator, Label* trueTarget, Label* falseTarget, bool fallThroughMeansTrue)
+{
+    if (m_expr1->hasConditionContextCodegen()) {
+        RefPtr<Label> afterExpr1 = generator.newLabel();
+        if (m_operator == OpLogicalAnd)
+            generator.emitNodeInConditionContext(m_expr1, afterExpr1.get(), falseTarget, true);
+        else 
+            generator.emitNodeInConditionContext(m_expr1, trueTarget, afterExpr1.get(), false);
+        generator.emitLabel(afterExpr1.get());
+    } else {
+        RegisterID* temp = generator.emitNode(m_expr1);
+        if (m_operator == OpLogicalAnd)
+            generator.emitJumpIfFalse(temp, falseTarget);
+        else
+            generator.emitJumpIfTrue(temp, trueTarget);
+    }
+
+    if (m_expr2->hasConditionContextCodegen())
+        generator.emitNodeInConditionContext(m_expr2, trueTarget, falseTarget, fallThroughMeansTrue);
+    else {
+        RegisterID* temp = generator.emitNode(m_expr2);
+        if (fallThroughMeansTrue)
+            generator.emitJumpIfFalse(temp, falseTarget);
+        else
+            generator.emitJumpIfTrue(temp, trueTarget);
+    }
+}
+
+// ------------------------------ ConditionalNode ------------------------------
+
+RegisterID* ConditionalNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
+{
+    RefPtr<RegisterID> newDst = generator.finalDestination(dst);
+    RefPtr<Label> beforeElse = generator.newLabel();
+    RefPtr<Label> afterElse = generator.newLabel();
+
+    if (m_logical->hasConditionContextCodegen()) {
+        RefPtr<Label> beforeThen = generator.newLabel();
+        generator.emitNodeInConditionContext(m_logical, beforeThen.get(), beforeElse.get(), true);
+        generator.emitLabel(beforeThen.get());
+    } else {
+        RegisterID* cond = generator.emitNode(m_logical);
+        generator.emitJumpIfFalse(cond, beforeElse.get());
+    }
+
+    generator.emitNode(newDst.get(), m_expr1);
+    generator.emitJump(afterElse.get());
+
+    generator.emitLabel(beforeElse.get());
+    generator.emitNode(newDst.get(), m_expr2);
+
+    generator.emitLabel(afterElse.get());
+
+    return newDst.get();
+}
+
+// ------------------------------ ReadModifyResolveNode -----------------------------------
+
+// FIXME: should this be moved to be a method on BytecodeGenerator?
+static ALWAYS_INLINE RegisterID* emitReadModifyAssignment(BytecodeGenerator& generator, RegisterID* dst, RegisterID* src1, ExpressionNode* m_right, Operator oper, OperandTypes types, ReadModifyResolveNode* emitExpressionInfoForMe = 0)
+{
+    OpcodeID opcodeID;
+    switch (oper) {
+        case OpMultEq:
+            opcodeID = op_mul;
+            break;
+        case OpDivEq:
+            opcodeID = op_div;
+            break;
+        case OpPlusEq:
+            if (m_right->isAdd() && m_right->resultDescriptor().definitelyIsString())
+                return static_cast<AddNode*>(m_right)->emitStrcat(generator, dst, src1, emitExpressionInfoForMe);
+            opcodeID = op_add;
+            break;
+        case OpMinusEq:
+            opcodeID = op_sub;
+            break;
+        case OpLShift:
+            opcodeID = op_lshift;
+            break;
+        case OpRShift:
+            opcodeID = op_rshift;
+            break;
+        case OpURShift:
+            opcodeID = op_urshift;
+            break;
+        case OpAndEq:
+            opcodeID = op_bitand;
+            break;
+        case OpXOrEq:
+            opcodeID = op_bitxor;
+            break;
+        case OpOrEq:
+            opcodeID = op_bitor;
+            break;
+        case OpModEq:
+            opcodeID = op_mod;
+            break;
+        default:
+            ASSERT_NOT_REACHED();
+            return dst;
+    }
+
+    RegisterID* src2 = generator.emitNode(m_right);
+
+    // Certain read-modify nodes require expression info to be emitted *after* m_right has been generated.
+    // If this is required the node is passed as 'emitExpressionInfoForMe'; do so now.
+    if (emitExpressionInfoForMe)
+        generator.emitExpressionInfo(emitExpressionInfoForMe->divot(), emitExpressionInfoForMe->startOffset(), emitExpressionInfoForMe->endOffset());
+
+    return generator.emitBinaryOp(opcodeID, dst, src1, src2, types);
+}
+
+RegisterID* ReadModifyResolveNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
+{
+    if (RegisterID* local = generator.registerFor(m_ident)) {
+        if (generator.isLocalConstant(m_ident)) {
+            return emitReadModifyAssignment(generator, generator.finalDestination(dst), local, m_right, m_operator, OperandTypes(ResultType::unknownType(), m_right->resultDescriptor()));
+        }
+        
+        if (generator.leftHandSideNeedsCopy(m_rightHasAssignments, m_right->isPure(generator))) {
+            RefPtr<RegisterID> result = generator.newTemporary();
+            generator.emitMove(result.get(), local);
+            emitReadModifyAssignment(generator, result.get(), result.get(), m_right, m_operator, OperandTypes(ResultType::unknownType(), m_right->resultDescriptor()));
+            generator.emitMove(local, result.get());
+            return generator.moveToDestinationIfNeeded(dst, result.get());
+        }
+        
+        RegisterID* result = emitReadModifyAssignment(generator, local, local, m_right, m_operator, OperandTypes(ResultType::unknownType(), m_right->resultDescriptor()));
+        return generator.moveToDestinationIfNeeded(dst, result);
+    }
+
+    int index = 0;
+    size_t depth = 0;
+    JSObject* globalObject = 0;
+    bool requiresDynamicChecks = false;
+    if (generator.findScopedProperty(m_ident, index, depth, true, requiresDynamicChecks, globalObject) && index != missingSymbolMarker() && !requiresDynamicChecks) {
+        RefPtr<RegisterID> src1 = generator.emitGetScopedVar(generator.tempDestination(dst), depth, index, globalObject);
+        RegisterID* result = emitReadModifyAssignment(generator, generator.finalDestination(dst, src1.get()), src1.get(), m_right, m_operator, OperandTypes(ResultType::unknownType(), m_right->resultDescriptor()));
+        generator.emitPutScopedVar(depth, index, result, globalObject);
+        return result;
+    }
+
+    RefPtr<RegisterID> src1 = generator.tempDestination(dst);
+    generator.emitExpressionInfo(divot() - startOffset() + m_ident.length(), m_ident.length(), 0);
+    RefPtr<RegisterID> base = generator.emitResolveWithBase(generator.newTemporary(), src1.get(), m_ident);
+    RegisterID* result = emitReadModifyAssignment(generator, generator.finalDestination(dst, src1.get()), src1.get(), m_right, m_operator, OperandTypes(ResultType::unknownType(), m_right->resultDescriptor()), this);
+    return generator.emitPutById(base.get(), m_ident, result);
+}
+
+// ------------------------------ AssignResolveNode -----------------------------------
+
+RegisterID* AssignResolveNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
+{
+    if (RegisterID* local = generator.registerFor(m_ident)) {
+        if (generator.isLocalConstant(m_ident))
+            return generator.emitNode(dst, m_right);
+        
+        RegisterID* result = generator.emitNode(local, m_right);
+        return generator.moveToDestinationIfNeeded(dst, result);
+    }
+
+    int index = 0;
+    size_t depth = 0;
+    JSObject* globalObject = 0;
+    bool requiresDynamicChecks = false;
+    if (generator.findScopedProperty(m_ident, index, depth, true, requiresDynamicChecks, globalObject) && index != missingSymbolMarker() && !requiresDynamicChecks) {
+        if (dst == generator.ignoredResult())
+            dst = 0;
+        RegisterID* value = generator.emitNode(dst, m_right);
+        generator.emitPutScopedVar(depth, index, value, globalObject);
+        return value;
+    }
+
+    RefPtr<RegisterID> base = generator.emitResolveBaseForPut(generator.newTemporary(), m_ident);
+    if (dst == generator.ignoredResult())
+        dst = 0;
+    RegisterID* value = generator.emitNode(dst, m_right);
+    generator.emitExpressionInfo(divot(), startOffset(), endOffset());
+    return generator.emitPutById(base.get(), m_ident, value);
+}
+
+// ------------------------------ AssignDotNode -----------------------------------
+
+RegisterID* AssignDotNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
+{
+    RefPtr<RegisterID> base = generator.emitNodeForLeftHandSide(m_base, m_rightHasAssignments, m_right->isPure(generator));
+    RefPtr<RegisterID> value = generator.destinationForAssignResult(dst);
+    RegisterID* result = generator.emitNode(value.get(), m_right);
+    generator.emitExpressionInfo(divot(), startOffset(), endOffset());
+    generator.emitPutById(base.get(), m_ident, result);
+    return generator.moveToDestinationIfNeeded(dst, result);
+}
+
+// ------------------------------ ReadModifyDotNode -----------------------------------
+
+RegisterID* ReadModifyDotNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
+{
+    RefPtr<RegisterID> base = generator.emitNodeForLeftHandSide(m_base, m_rightHasAssignments, m_right->isPure(generator));
+
+    generator.emitExpressionInfo(divot() - m_subexpressionDivotOffset, startOffset() - m_subexpressionDivotOffset, m_subexpressionEndOffset);
+    RefPtr<RegisterID> value = generator.emitGetById(generator.tempDestination(dst), base.get(), m_ident);
+    RegisterID* updatedValue = emitReadModifyAssignment(generator, generator.finalDestination(dst, value.get()), value.get(), m_right, m_operator, OperandTypes(ResultType::unknownType(), m_right->resultDescriptor()));
+
+    generator.emitExpressionInfo(divot(), startOffset(), endOffset());
+    return generator.emitPutById(base.get(), m_ident, updatedValue);
+}
+
+// ------------------------------ AssignErrorNode -----------------------------------
+
+RegisterID* AssignErrorNode::emitBytecode(BytecodeGenerator& generator, RegisterID*)
+{
+    return emitThrowReferenceError(generator, "Left side of assignment is not a reference.");
+}
+
+// ------------------------------ AssignBracketNode -----------------------------------
+
+RegisterID* AssignBracketNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
+{
+    RefPtr<RegisterID> base = generator.emitNodeForLeftHandSide(m_base, m_subscriptHasAssignments || m_rightHasAssignments, m_subscript->isPure(generator) && m_right->isPure(generator));
+    RefPtr<RegisterID> property = generator.emitNodeForLeftHandSide(m_subscript, m_rightHasAssignments, m_right->isPure(generator));
+    RefPtr<RegisterID> value = generator.destinationForAssignResult(dst);
+    RegisterID* result = generator.emitNode(value.get(), m_right);
+
+    generator.emitExpressionInfo(divot(), startOffset(), endOffset());
+    generator.emitPutByVal(base.get(), property.get(), result);
+    return generator.moveToDestinationIfNeeded(dst, result);
+}
+
+// ------------------------------ ReadModifyBracketNode -----------------------------------
+
+RegisterID* ReadModifyBracketNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
+{
+    RefPtr<RegisterID> base = generator.emitNodeForLeftHandSide(m_base, m_subscriptHasAssignments || m_rightHasAssignments, m_subscript->isPure(generator) && m_right->isPure(generator));
+    RefPtr<RegisterID> property = generator.emitNodeForLeftHandSide(m_subscript, m_rightHasAssignments, m_right->isPure(generator));
+
+    generator.emitExpressionInfo(divot() - m_subexpressionDivotOffset, startOffset() - m_subexpressionDivotOffset, m_subexpressionEndOffset);
+    RefPtr<RegisterID> value = generator.emitGetByVal(generator.tempDestination(dst), base.get(), property.get());
+    RegisterID* updatedValue = emitReadModifyAssignment(generator, generator.finalDestination(dst, value.get()), value.get(), m_right, m_operator, OperandTypes(ResultType::unknownType(), m_right->resultDescriptor()));
+
+    generator.emitExpressionInfo(divot(), startOffset(), endOffset());
+    generator.emitPutByVal(base.get(), property.get(), updatedValue);
+
+    return updatedValue;
+}
+
+// ------------------------------ CommaNode ------------------------------------
+
+RegisterID* CommaNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
+{
+    ASSERT(m_expressions.size() > 1);
+    for (size_t i = 0; i < m_expressions.size() - 1; i++)
+        generator.emitNode(generator.ignoredResult(), m_expressions[i]);
+    return generator.emitNode(dst, m_expressions.last());
+}
+
+// ------------------------------ ConstDeclNode ------------------------------------
+
+RegisterID* ConstDeclNode::emitCodeSingle(BytecodeGenerator& generator)
+{
+    if (RegisterID* local = generator.constRegisterFor(m_ident)) {
+        if (!m_init)
+            return local;
+
+        return generator.emitNode(local, m_init);
+    }
+
+    if (generator.codeType() != EvalCode) {
+        if (m_init)
+            return generator.emitNode(m_init);
+        else
+            return generator.emitResolve(generator.newTemporary(), m_ident);
+    }
+    // FIXME: While this code should only be hit in eval code, it will potentially
+    // assign to the wrong base if m_ident exists in an intervening dynamic scope.
+    RefPtr<RegisterID> base = generator.emitResolveBase(generator.newTemporary(), m_ident);
+    RegisterID* value = m_init ? generator.emitNode(m_init) : generator.emitLoad(0, jsUndefined());
+    return generator.emitPutById(base.get(), m_ident, value);
+}
+
+RegisterID* ConstDeclNode::emitBytecode(BytecodeGenerator& generator, RegisterID*)
+{
+    RegisterID* result = 0;
+    for (ConstDeclNode* n = this; n; n = n->m_next)
+        result = n->emitCodeSingle(generator);
+
+    return result;
+}
+
+// ------------------------------ ConstStatementNode -----------------------------
+
+RegisterID* ConstStatementNode::emitBytecode(BytecodeGenerator& generator, RegisterID*)
+{
+    generator.emitDebugHook(WillExecuteStatement, firstLine(), lastLine());
+    return generator.emitNode(m_next);
+}
+
+// ------------------------------ SourceElements -------------------------------
+
+
+inline StatementNode* SourceElements::lastStatement() const
+{
+    size_t size = m_statements.size();
+    return size ? m_statements[size - 1] : 0;
+}
+
+inline void SourceElements::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
+{
+    size_t size = m_statements.size();
+    for (size_t i = 0; i < size; ++i)
+        generator.emitNode(dst, m_statements[i]);
+}
+
+// ------------------------------ BlockNode ------------------------------------
+
+inline StatementNode* BlockNode::lastStatement() const
+{
+    return m_statements ? m_statements->lastStatement() : 0;
+}
+
+inline StatementNode* BlockNode::singleStatement() const
+{
+    return m_statements ? m_statements->singleStatement() : 0;
+}
+
+RegisterID* BlockNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
+{
+    if (m_statements)
+        m_statements->emitBytecode(generator, dst);
+    return 0;
+}
+
+// ------------------------------ EmptyStatementNode ---------------------------
+
+RegisterID* EmptyStatementNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
+{
+    generator.emitDebugHook(WillExecuteStatement, firstLine(), lastLine());
+    return dst;
+}
+
+// ------------------------------ DebuggerStatementNode ---------------------------
+
+RegisterID* DebuggerStatementNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
+{
+    generator.emitDebugHook(DidReachBreakpoint, firstLine(), lastLine());
+    return dst;
+}
+
+// ------------------------------ ExprStatementNode ----------------------------
+
+RegisterID* ExprStatementNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
+{
+    ASSERT(m_expr);
+    generator.emitDebugHook(WillExecuteStatement, firstLine(), lastLine()); 
+    return generator.emitNode(dst, m_expr);
+}
+
+// ------------------------------ VarStatementNode ----------------------------
+
+RegisterID* VarStatementNode::emitBytecode(BytecodeGenerator& generator, RegisterID*)
+{
+    ASSERT(m_expr);
+    generator.emitDebugHook(WillExecuteStatement, firstLine(), lastLine());
+    return generator.emitNode(m_expr);
+}
+
+// ------------------------------ IfNode ---------------------------------------
+
+RegisterID* IfNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
+{
+    generator.emitDebugHook(WillExecuteStatement, firstLine(), lastLine());
+    
+    RefPtr<Label> afterThen = generator.newLabel();
+
+    if (m_condition->hasConditionContextCodegen()) {
+        RefPtr<Label> beforeThen = generator.newLabel();
+        generator.emitNodeInConditionContext(m_condition, beforeThen.get(), afterThen.get(), true);
+        generator.emitLabel(beforeThen.get());
+    } else {
+        RegisterID* cond = generator.emitNode(m_condition);
+        generator.emitJumpIfFalse(cond, afterThen.get());
+    }
+
+    generator.emitNode(dst, m_ifBlock);
+    generator.emitLabel(afterThen.get());
+
+    // FIXME: This should return the last statement executed so that it can be returned as a Completion.
+    return 0;
+}
+
+// ------------------------------ IfElseNode ---------------------------------------
+
+RegisterID* IfElseNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
+{
+    generator.emitDebugHook(WillExecuteStatement, firstLine(), lastLine());
+    
+    RefPtr<Label> beforeElse = generator.newLabel();
+    RefPtr<Label> afterElse = generator.newLabel();
+
+    if (m_condition->hasConditionContextCodegen()) {
+        RefPtr<Label> beforeThen = generator.newLabel();
+        generator.emitNodeInConditionContext(m_condition, beforeThen.get(), beforeElse.get(), true);
+        generator.emitLabel(beforeThen.get());
+    } else {
+        RegisterID* cond = generator.emitNode(m_condition);
+        generator.emitJumpIfFalse(cond, beforeElse.get());
+    }
+
+    generator.emitNode(dst, m_ifBlock);
+    generator.emitJump(afterElse.get());
+
+    generator.emitLabel(beforeElse.get());
+
+    generator.emitNode(dst, m_elseBlock);
+
+    generator.emitLabel(afterElse.get());
+
+    // FIXME: This should return the last statement executed so that it can be returned as a Completion.
+    return 0;
+}
+
+// ------------------------------ DoWhileNode ----------------------------------
+
+RegisterID* DoWhileNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
+{
+    RefPtr<LabelScope> scope = generator.newLabelScope(LabelScope::Loop);
+
+    RefPtr<Label> topOfLoop = generator.newLabel();
+    generator.emitLabel(topOfLoop.get());
+
+    generator.emitDebugHook(WillExecuteStatement, firstLine(), lastLine());
+   
+    RefPtr<RegisterID> result = generator.emitNode(dst, m_statement);
+
+    generator.emitLabel(scope->continueTarget());
+    generator.emitDebugHook(WillExecuteStatement, m_expr->lineNo(), m_expr->lineNo());
+    if (m_expr->hasConditionContextCodegen())
+        generator.emitNodeInConditionContext(m_expr, topOfLoop.get(), scope->breakTarget(), false);
+    else {
+        RegisterID* cond = generator.emitNode(m_expr);
+        generator.emitJumpIfTrue(cond, topOfLoop.get());
+    }
+
+    generator.emitLabel(scope->breakTarget());
+    return result.get();
+}
+
+// ------------------------------ WhileNode ------------------------------------
+
+RegisterID* WhileNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
+{
+    RefPtr<LabelScope> scope = generator.newLabelScope(LabelScope::Loop);
+
+    generator.emitJump(scope->continueTarget());
+
+    RefPtr<Label> topOfLoop = generator.newLabel();
+    generator.emitLabel(topOfLoop.get());
+    
+    generator.emitNode(dst, m_statement);
+
+    generator.emitLabel(scope->continueTarget());
+    generator.emitDebugHook(WillExecuteStatement, m_expr->lineNo(), m_expr->lineNo());
+
+    if (m_expr->hasConditionContextCodegen())
+        generator.emitNodeInConditionContext(m_expr, topOfLoop.get(), scope->breakTarget(), false);
+    else {
+        RegisterID* cond = generator.emitNode(m_expr);
+        generator.emitJumpIfTrue(cond, topOfLoop.get());
+    }
+
+    generator.emitLabel(scope->breakTarget());
+    
+    // FIXME: This should return the last statement executed so that it can be returned as a Completion
+    return 0;
+}
+
+// ------------------------------ ForNode --------------------------------------
+
+RegisterID* ForNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
+{
+    RefPtr<LabelScope> scope = generator.newLabelScope(LabelScope::Loop);
+
+    generator.emitDebugHook(WillExecuteStatement, firstLine(), lastLine());
+
+    if (m_expr1)
+        generator.emitNode(generator.ignoredResult(), m_expr1);
+
+    RefPtr<Label> condition = generator.newLabel();
+    generator.emitJump(condition.get());
+
+    RefPtr<Label> topOfLoop = generator.newLabel();
+    generator.emitLabel(topOfLoop.get());
+
+    RefPtr<RegisterID> result = generator.emitNode(dst, m_statement);
+
+    generator.emitLabel(scope->continueTarget());
+    generator.emitDebugHook(WillExecuteStatement, firstLine(), lastLine());
+    if (m_expr3)
+        generator.emitNode(generator.ignoredResult(), m_expr3);
+
+    generator.emitLabel(condition.get());
+    if (m_expr2) {
+        if (m_expr2->hasConditionContextCodegen())
+            generator.emitNodeInConditionContext(m_expr2, topOfLoop.get(), scope->breakTarget(), false);
+        else {
+            RegisterID* cond = generator.emitNode(m_expr2);
+            generator.emitJumpIfTrue(cond, topOfLoop.get());
+        }
+    } else
+        generator.emitJump(topOfLoop.get());
+
+    generator.emitLabel(scope->breakTarget());
+    return result.get();
+}
+
+// ------------------------------ ForInNode ------------------------------------
+
+RegisterID* ForInNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
+{
+    RefPtr<LabelScope> scope = generator.newLabelScope(LabelScope::Loop);
+
+    if (!m_lexpr->isLocation())
+        return emitThrowReferenceError(generator, "Left side of for-in statement is not a reference.");
+
+    generator.emitDebugHook(WillExecuteStatement, firstLine(), lastLine());
+
+    if (m_init)
+        generator.emitNode(generator.ignoredResult(), m_init);
+
+    RefPtr<RegisterID> base = generator.newTemporary();
+    generator.emitNode(base.get(), m_expr);
+    RefPtr<RegisterID> i = generator.newTemporary();
+    RefPtr<RegisterID> size = generator.newTemporary();
+    RefPtr<RegisterID> expectedSubscript;
+    RefPtr<RegisterID> iter = generator.emitGetPropertyNames(generator.newTemporary(), base.get(), i.get(), size.get(), scope->breakTarget());
+    generator.emitJump(scope->continueTarget());
+
+    RefPtr<Label> loopStart = generator.newLabel();
+    generator.emitLabel(loopStart.get());
+
+    RegisterID* propertyName;
+    bool optimizedForinAccess = false;
+    if (m_lexpr->isResolveNode()) {
+        const Identifier& ident = static_cast<ResolveNode*>(m_lexpr)->identifier();
+        propertyName = generator.registerFor(ident);
+        if (!propertyName) {
+            propertyName = generator.newTemporary();
+            RefPtr<RegisterID> protect = propertyName;
+            RegisterID* base = generator.emitResolveBaseForPut(generator.newTemporary(), ident);
+
+            generator.emitExpressionInfo(divot(), startOffset(), endOffset());
+            generator.emitPutById(base, ident, propertyName);
+        } else {
+            expectedSubscript = generator.emitMove(generator.newTemporary(), propertyName);
+            generator.pushOptimisedForIn(expectedSubscript.get(), iter.get(), i.get(), propertyName);
+            optimizedForinAccess = true;
+        }
+    } else if (m_lexpr->isDotAccessorNode()) {
+        DotAccessorNode* assignNode = static_cast<DotAccessorNode*>(m_lexpr);
+        const Identifier& ident = assignNode->identifier();
+        propertyName = generator.newTemporary();
+        RefPtr<RegisterID> protect = propertyName;
+        RegisterID* base = generator.emitNode(assignNode->base());
+
+        generator.emitExpressionInfo(assignNode->divot(), assignNode->startOffset(), assignNode->endOffset());
+        generator.emitPutById(base, ident, propertyName);
+    } else {
+        ASSERT(m_lexpr->isBracketAccessorNode());
+        BracketAccessorNode* assignNode = static_cast<BracketAccessorNode*>(m_lexpr);
+        propertyName = generator.newTemporary();
+        RefPtr<RegisterID> protect = propertyName;
+        RefPtr<RegisterID> base = generator.emitNode(assignNode->base());
+        RegisterID* subscript = generator.emitNode(assignNode->subscript());
+        
+        generator.emitExpressionInfo(assignNode->divot(), assignNode->startOffset(), assignNode->endOffset());
+        generator.emitPutByVal(base.get(), subscript, propertyName);
+    }   
+
+    generator.emitNode(dst, m_statement);
+
+    if (optimizedForinAccess)
+        generator.popOptimisedForIn();
+
+    generator.emitLabel(scope->continueTarget());
+    generator.emitNextPropertyName(propertyName, base.get(), i.get(), size.get(), iter.get(), loopStart.get());
+    generator.emitDebugHook(WillExecuteStatement, firstLine(), lastLine());
+    generator.emitLabel(scope->breakTarget());
+    return dst;
+}
+
+// ------------------------------ ContinueNode ---------------------------------
+
+// ECMA 12.7
+RegisterID* ContinueNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
+{
+    generator.emitDebugHook(WillExecuteStatement, firstLine(), lastLine());
+    
+    LabelScope* scope = generator.continueTarget(m_ident);
+
+    if (!scope) {
+        if (m_ident.isEmpty())
+            return emitThrowSyntaxError(generator, "Invalid continue statement.");
+        return emitThrowSyntaxError(generator, makeUString("Undefined label: '", m_ident.ustring(), "'."));
+    }
+
+    generator.emitJumpScopes(scope->continueTarget(), scope->scopeDepth());
+    return dst;
+}
+
+// ------------------------------ BreakNode ------------------------------------
+
+// ECMA 12.8
+RegisterID* BreakNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
+{
+    generator.emitDebugHook(WillExecuteStatement, firstLine(), lastLine());
+    
+    LabelScope* scope = generator.breakTarget(m_ident);
+    
+    if (!scope) {
+        if (m_ident.isEmpty())
+            return emitThrowSyntaxError(generator, "Invalid break statement.");
+        return emitThrowSyntaxError(generator, makeUString("Undefined label: '", m_ident.ustring(), "'."));
+    }
+
+    generator.emitJumpScopes(scope->breakTarget(), scope->scopeDepth());
+    return dst;
+}
+
+// ------------------------------ ReturnNode -----------------------------------
+
+RegisterID* ReturnNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
+{
+    generator.emitDebugHook(WillExecuteStatement, firstLine(), lastLine());
+    if (generator.codeType() != FunctionCode)
+        return emitThrowSyntaxError(generator, "Invalid return statement.");
+
+    if (dst == generator.ignoredResult())
+        dst = 0;
+    RegisterID* r0 = m_value ? generator.emitNode(dst, m_value) : generator.emitLoad(dst, jsUndefined());
+    RefPtr<RegisterID> returnRegister;
+    if (generator.scopeDepth()) {
+        RefPtr<Label> l0 = generator.newLabel();
+        if (generator.hasFinaliser() && !r0->isTemporary()) {
+            returnRegister = generator.emitMove(generator.newTemporary(), r0);
+            r0 = returnRegister.get();
+        }
+        generator.emitJumpScopes(l0.get(), 0);
+        generator.emitLabel(l0.get());
+    }
+    generator.emitDebugHook(WillLeaveCallFrame, firstLine(), lastLine());
+    return generator.emitReturn(r0);
+}
+
+// ------------------------------ WithNode -------------------------------------
+
+RegisterID* WithNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
+{
+    generator.emitDebugHook(WillExecuteStatement, firstLine(), lastLine());
+    
+    RefPtr<RegisterID> scope = generator.newTemporary();
+    generator.emitNode(scope.get(), m_expr); // scope must be protected until popped
+    generator.emitExpressionInfo(m_divot, m_expressionLength, 0);
+    generator.emitPushScope(scope.get());
+    RegisterID* result = generator.emitNode(dst, m_statement);
+    generator.emitPopScope();
+    return result;
+}
+
+// ------------------------------ CaseClauseNode --------------------------------
+
+inline void CaseClauseNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
+{
+    if (m_statements)
+        m_statements->emitBytecode(generator, dst);
+}
+
+// ------------------------------ CaseBlockNode --------------------------------
+
+enum SwitchKind { 
+    SwitchUnset = 0,
+    SwitchNumber = 1, 
+    SwitchString = 2, 
+    SwitchNeither = 3 
+};
+
+static void processClauseList(ClauseListNode* list, Vector<ExpressionNode*, 8>& literalVector, SwitchKind& typeForTable, bool& singleCharacterSwitch, int32_t& min_num, int32_t& max_num)
+{
+    for (; list; list = list->getNext()) {
+        ExpressionNode* clauseExpression = list->getClause()->expr();
+        literalVector.append(clauseExpression);
+        if (clauseExpression->isNumber()) {
+            double value = static_cast<NumberNode*>(clauseExpression)->value();
+            int32_t intVal = static_cast<int32_t>(value);
+            if ((typeForTable & ~SwitchNumber) || (intVal != value)) {
+                typeForTable = SwitchNeither;
+                break;
+            }
+            if (intVal < min_num)
+                min_num = intVal;
+            if (intVal > max_num)
+                max_num = intVal;
+            typeForTable = SwitchNumber;
+            continue;
+        }
+        if (clauseExpression->isString()) {
+            if (typeForTable & ~SwitchString) {
+                typeForTable = SwitchNeither;
+                break;
+            }
+            const UString& value = static_cast<StringNode*>(clauseExpression)->value().ustring();
+            if (singleCharacterSwitch &= value.length() == 1) {
+                int32_t intVal = value.impl()->characters()[0];
+                if (intVal < min_num)
+                    min_num = intVal;
+                if (intVal > max_num)
+                    max_num = intVal;
+            }
+            typeForTable = SwitchString;
+            continue;
+        }
+        typeForTable = SwitchNeither;
+        break;        
+    }
+}
+    
+SwitchInfo::SwitchType CaseBlockNode::tryOptimizedSwitch(Vector<ExpressionNode*, 8>& literalVector, int32_t& min_num, int32_t& max_num)
+{
+    SwitchKind typeForTable = SwitchUnset;
+    bool singleCharacterSwitch = true;
+    
+    processClauseList(m_list1, literalVector, typeForTable, singleCharacterSwitch, min_num, max_num);
+    processClauseList(m_list2, literalVector, typeForTable, singleCharacterSwitch, min_num, max_num);
+    
+    if (typeForTable == SwitchUnset || typeForTable == SwitchNeither)
+        return SwitchInfo::SwitchNone;
+    
+    if (typeForTable == SwitchNumber) {
+        int32_t range = max_num - min_num;
+        if (min_num <= max_num && range <= 1000 && (range / literalVector.size()) < 10)
+            return SwitchInfo::SwitchImmediate;
+        return SwitchInfo::SwitchNone;
+    } 
+    
+    ASSERT(typeForTable == SwitchString);
+    
+    if (singleCharacterSwitch) {
+        int32_t range = max_num - min_num;
+        if (min_num <= max_num && range <= 1000 && (range / literalVector.size()) < 10)
+            return SwitchInfo::SwitchCharacter;
+    }
+
+    return SwitchInfo::SwitchString;
+}
+
+RegisterID* CaseBlockNode::emitBytecodeForBlock(BytecodeGenerator& generator, RegisterID* switchExpression, RegisterID* dst)
+{
+    RefPtr<Label> defaultLabel;
+    Vector<RefPtr<Label>, 8> labelVector;
+    Vector<ExpressionNode*, 8> literalVector;
+    int32_t min_num = std::numeric_limits<int32_t>::max();
+    int32_t max_num = std::numeric_limits<int32_t>::min();
+    SwitchInfo::SwitchType switchType = tryOptimizedSwitch(literalVector, min_num, max_num);
+
+    if (switchType != SwitchInfo::SwitchNone) {
+        // Prepare the various labels
+        for (uint32_t i = 0; i < literalVector.size(); i++)
+            labelVector.append(generator.newLabel());
+        defaultLabel = generator.newLabel();
+        generator.beginSwitch(switchExpression, switchType);
+    } else {
+        // Setup jumps
+        for (ClauseListNode* list = m_list1; list; list = list->getNext()) {
+            RefPtr<RegisterID> clauseVal = generator.newTemporary();
+            generator.emitNode(clauseVal.get(), list->getClause()->expr());
+            generator.emitBinaryOp(op_stricteq, clauseVal.get(), clauseVal.get(), switchExpression, OperandTypes());
+            labelVector.append(generator.newLabel());
+            generator.emitJumpIfTrue(clauseVal.get(), labelVector[labelVector.size() - 1].get());
+        }
+        
+        for (ClauseListNode* list = m_list2; list; list = list->getNext()) {
+            RefPtr<RegisterID> clauseVal = generator.newTemporary();
+            generator.emitNode(clauseVal.get(), list->getClause()->expr());
+            generator.emitBinaryOp(op_stricteq, clauseVal.get(), clauseVal.get(), switchExpression, OperandTypes());
+            labelVector.append(generator.newLabel());
+            generator.emitJumpIfTrue(clauseVal.get(), labelVector[labelVector.size() - 1].get());
+        }
+        defaultLabel = generator.newLabel();
+        generator.emitJump(defaultLabel.get());
+    }
+
+    RegisterID* result = 0;
+
+    size_t i = 0;
+    for (ClauseListNode* list = m_list1; list; list = list->getNext()) {
+        generator.emitLabel(labelVector[i++].get());
+        list->getClause()->emitBytecode(generator, dst);
+    }
+
+    if (m_defaultClause) {
+        generator.emitLabel(defaultLabel.get());
+        m_defaultClause->emitBytecode(generator, dst);
+    }
+
+    for (ClauseListNode* list = m_list2; list; list = list->getNext()) {
+        generator.emitLabel(labelVector[i++].get());
+        list->getClause()->emitBytecode(generator, dst);
+    }
+    if (!m_defaultClause)
+        generator.emitLabel(defaultLabel.get());
+
+    ASSERT(i == labelVector.size());
+    if (switchType != SwitchInfo::SwitchNone) {
+        ASSERT(labelVector.size() == literalVector.size());
+        generator.endSwitch(labelVector.size(), labelVector.data(), literalVector.data(), defaultLabel.get(), min_num, max_num);
+    }
+    return result;
+}
+
+// ------------------------------ SwitchNode -----------------------------------
+
+RegisterID* SwitchNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
+{
+    generator.emitDebugHook(WillExecuteStatement, firstLine(), lastLine());
+    
+    RefPtr<LabelScope> scope = generator.newLabelScope(LabelScope::Switch);
+
+    RefPtr<RegisterID> r0 = generator.emitNode(m_expr);
+    RegisterID* r1 = m_block->emitBytecodeForBlock(generator, r0.get(), dst);
+
+    generator.emitLabel(scope->breakTarget());
+    return r1;
+}
+
+// ------------------------------ LabelNode ------------------------------------
+
+RegisterID* LabelNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
+{
+    generator.emitDebugHook(WillExecuteStatement, firstLine(), lastLine());
+
+    if (generator.breakTarget(m_name))
+        return emitThrowSyntaxError(generator, makeUString("Duplicate label: ", m_name.ustring(), "."));
+
+    RefPtr<LabelScope> scope = generator.newLabelScope(LabelScope::NamedLabel, &m_name);
+    RegisterID* r0 = generator.emitNode(dst, m_statement);
+
+    generator.emitLabel(scope->breakTarget());
+    return r0;
+}
+
+// ------------------------------ ThrowNode ------------------------------------
+
+RegisterID* ThrowNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
+{
+    generator.emitDebugHook(WillExecuteStatement, firstLine(), lastLine());
+
+    if (dst == generator.ignoredResult())
+        dst = 0;
+    RefPtr<RegisterID> expr = generator.emitNode(m_expr);
+    generator.emitExpressionInfo(divot(), startOffset(), endOffset());
+    generator.emitThrow(expr.get());
+    return 0;
+}
+
+// ------------------------------ TryNode --------------------------------------
+
+RegisterID* TryNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
+{
+    // NOTE: The catch and finally blocks must be labeled explicitly, so the
+    // optimizer knows they may be jumped to from anywhere.
+
+    generator.emitDebugHook(WillExecuteStatement, firstLine(), lastLine());
+
+    RefPtr<Label> tryStartLabel = generator.newLabel();
+    RefPtr<Label> finallyStart;
+    RefPtr<RegisterID> finallyReturnAddr;
+    if (m_finallyBlock) {
+        finallyStart = generator.newLabel();
+        finallyReturnAddr = generator.newTemporary();
+        generator.pushFinallyContext(finallyStart.get(), finallyReturnAddr.get());
+    }
+
+    generator.emitLabel(tryStartLabel.get());
+    generator.emitNode(dst, m_tryBlock);
+
+    if (m_catchBlock) {
+        RefPtr<Label> catchEndLabel = generator.newLabel();
+        
+        // Normal path: jump over the catch block.
+        generator.emitJump(catchEndLabel.get());
+
+        // Uncaught exception path: the catch block.
+        RefPtr<Label> here = generator.emitLabel(generator.newLabel().get());
+        RefPtr<RegisterID> exceptionRegister = generator.emitCatch(generator.newTemporary(), tryStartLabel.get(), here.get());
+        if (m_catchHasEval) {
+            RefPtr<RegisterID> dynamicScopeObject = generator.emitNewObject(generator.newTemporary());
+            generator.emitPutById(dynamicScopeObject.get(), m_exceptionIdent, exceptionRegister.get());
+            generator.emitMove(exceptionRegister.get(), dynamicScopeObject.get());
+            generator.emitPushScope(exceptionRegister.get());
+        } else
+            generator.emitPushNewScope(exceptionRegister.get(), m_exceptionIdent, exceptionRegister.get());
+        generator.emitNode(dst, m_catchBlock);
+        generator.emitPopScope();
+        generator.emitLabel(catchEndLabel.get());
+    }
+
+    if (m_finallyBlock) {
+        generator.popFinallyContext();
+        // there may be important registers live at the time we jump
+        // to a finally block (such as for a return or throw) so we
+        // ref the highest register ever used as a conservative
+        // approach to not clobbering anything important
+        RefPtr<RegisterID> highestUsedRegister = generator.highestUsedRegister();
+        RefPtr<Label> finallyEndLabel = generator.newLabel();
+
+        // Normal path: invoke the finally block, then jump over it.
+        generator.emitJumpSubroutine(finallyReturnAddr.get(), finallyStart.get());
+        generator.emitJump(finallyEndLabel.get());
+
+        // Uncaught exception path: invoke the finally block, then re-throw the exception.
+        RefPtr<Label> here = generator.emitLabel(generator.newLabel().get());
+        RefPtr<RegisterID> tempExceptionRegister = generator.emitCatch(generator.newTemporary(), tryStartLabel.get(), here.get());
+        generator.emitJumpSubroutine(finallyReturnAddr.get(), finallyStart.get());
+        generator.emitThrow(tempExceptionRegister.get());
+
+        // The finally block.
+        generator.emitLabel(finallyStart.get());
+        generator.emitNode(dst, m_finallyBlock);
+        generator.emitSubroutineReturn(finallyReturnAddr.get());
+
+        generator.emitLabel(finallyEndLabel.get());
+    }
+
+    return dst;
+}
+
+// ------------------------------ ScopeNode -----------------------------
+
+inline void ScopeNode::emitStatementsBytecode(BytecodeGenerator& generator, RegisterID* dst)
+{
+    if (m_data->m_statements)
+        m_data->m_statements->emitBytecode(generator, dst);
+}
+
+// ------------------------------ ProgramNode -----------------------------
+
+RegisterID* ProgramNode::emitBytecode(BytecodeGenerator& generator, RegisterID*)
+{
+    generator.emitDebugHook(WillExecuteProgram, firstLine(), lastLine());
+
+    RefPtr<RegisterID> dstRegister = generator.newTemporary();
+    generator.emitLoad(dstRegister.get(), jsUndefined());
+    emitStatementsBytecode(generator, dstRegister.get());
+
+    generator.emitDebugHook(DidExecuteProgram, firstLine(), lastLine());
+    generator.emitEnd(dstRegister.get());
+    return 0;
+}
+
+// ------------------------------ EvalNode -----------------------------
+
+RegisterID* EvalNode::emitBytecode(BytecodeGenerator& generator, RegisterID*)
+{
+    generator.emitDebugHook(WillExecuteProgram, firstLine(), lastLine());
+
+    RefPtr<RegisterID> dstRegister = generator.newTemporary();
+    generator.emitLoad(dstRegister.get(), jsUndefined());
+    emitStatementsBytecode(generator, dstRegister.get());
+
+    generator.emitDebugHook(DidExecuteProgram, firstLine(), lastLine());
+    generator.emitEnd(dstRegister.get());
+    return 0;
+}
+
+// ------------------------------ FunctionBodyNode -----------------------------
+
+RegisterID* FunctionBodyNode::emitBytecode(BytecodeGenerator& generator, RegisterID*)
+{
+    generator.emitDebugHook(DidEnterCallFrame, firstLine(), lastLine());
+    emitStatementsBytecode(generator, generator.ignoredResult());
+
+    StatementNode* singleStatement = this->singleStatement();
+    ReturnNode* returnNode = 0;
+
+    // Check for a return statement at the end of a function composed of a single block.
+    if (singleStatement && singleStatement->isBlock()) {
+        StatementNode* lastStatementInBlock = static_cast<BlockNode*>(singleStatement)->lastStatement();
+        if (lastStatementInBlock && lastStatementInBlock->isReturnNode())
+            returnNode = static_cast<ReturnNode*>(lastStatementInBlock);
+    }
+
+    // If there is no return we must automatically insert one.
+    if (!returnNode) {
+        RegisterID* r0 = generator.isConstructor() ? generator.thisRegister() : generator.emitLoad(0, jsUndefined());
+        generator.emitDebugHook(WillLeaveCallFrame, firstLine(), lastLine());
+        generator.emitReturn(r0);
+        return 0;
+    }
+
+    // If there is a return statment, and it is the only statement in the function, check if this is a numeric compare.
+    if (static_cast<BlockNode*>(singleStatement)->singleStatement()) {
+        ExpressionNode* returnValueExpression = returnNode->value();
+        if (returnValueExpression && returnValueExpression->isSubtract()) {
+            ExpressionNode* lhsExpression = static_cast<SubNode*>(returnValueExpression)->lhs();
+            ExpressionNode* rhsExpression = static_cast<SubNode*>(returnValueExpression)->rhs();
+            if (lhsExpression->isResolveNode() && rhsExpression->isResolveNode()) {
+                generator.setIsNumericCompareFunction(generator.argumentNumberFor(static_cast<ResolveNode*>(lhsExpression)->identifier()) == 1
+                    && generator.argumentNumberFor(static_cast<ResolveNode*>(rhsExpression)->identifier()) == 2);
+            }
+        }
+    }
+
+    return 0;
+}
+
+// ------------------------------ FuncDeclNode ---------------------------------
+
+RegisterID* FuncDeclNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
+{
+    if (dst == generator.ignoredResult())
+        dst = 0;
+    return dst;
+}
+
+// ------------------------------ FuncExprNode ---------------------------------
+
+RegisterID* FuncExprNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
+{
+    return generator.emitNewFunctionExpression(generator.finalDestination(dst), this);
+}
+
+} // namespace JSC
diff --git a/Source/JavaScriptCore/bytecompiler/RegisterID.h b/Source/JavaScriptCore/bytecompiler/RegisterID.h
new file mode 100644
index 0000000..3532ad8
--- /dev/null
+++ b/Source/JavaScriptCore/bytecompiler/RegisterID.h
@@ -0,0 +1,121 @@
+/*
+ * Copyright (C) 2008 Apple Inc. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1.  Redistributions of source code must retain the above copyright
+ *     notice, this list of conditions and the following disclaimer.
+ * 2.  Redistributions in binary form must reproduce the above copyright
+ *     notice, this list of conditions and the following disclaimer in the
+ *     documentation and/or other materials provided with the distribution.
+ * 3.  Neither the name of Apple Computer, Inc. ("Apple") nor the names of
+ *     its contributors may be used to endorse or promote products derived
+ *     from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef RegisterID_h
+#define RegisterID_h
+
+#include <wtf/Assertions.h>
+#include <wtf/Noncopyable.h>
+#include <wtf/VectorTraits.h>
+
+namespace JSC {
+
+    class RegisterID : public Noncopyable {
+    public:
+        RegisterID()
+            : m_refCount(0)
+            , m_isTemporary(false)
+#ifndef NDEBUG
+            , m_didSetIndex(false)
+#endif
+        {
+        }
+
+        explicit RegisterID(int index)
+            : m_refCount(0)
+            , m_index(index)
+            , m_isTemporary(false)
+#ifndef NDEBUG
+            , m_didSetIndex(true)
+#endif
+        {
+        }
+
+        void setIndex(int index)
+        {
+            ASSERT(!m_refCount);
+#ifndef NDEBUG
+            m_didSetIndex = true;
+#endif
+            m_index = index;
+        }
+
+        void setTemporary()
+        {
+            m_isTemporary = true;
+        }
+
+        int index() const
+        {
+            ASSERT(m_didSetIndex);
+            return m_index;
+        }
+
+        bool isTemporary()
+        {
+            return m_isTemporary;
+        }
+
+        void ref()
+        {
+            ++m_refCount;
+        }
+
+        void deref()
+        {
+            --m_refCount;
+            ASSERT(m_refCount >= 0);
+        }
+
+        int refCount() const
+        {
+            return m_refCount;
+        }
+
+    private:
+
+        int m_refCount;
+        int m_index;
+        bool m_isTemporary;
+#ifndef NDEBUG
+        bool m_didSetIndex;
+#endif
+    };
+
+} // namespace JSC
+
+namespace WTF {
+
+    template<> struct VectorTraits<JSC::RegisterID> : VectorTraitsBase<true, JSC::RegisterID> {
+        static const bool needsInitialization = true;
+        static const bool canInitializeWithMemset = true; // Default initialization just sets everything to 0 or false, so this is safe.
+    };
+
+} // namespace WTF
+
+#endif // RegisterID_h