Update src/3rdparty/javascriptcore and adapt src/script to the changes

- Update qscriptvalueiterator test to expect length property when
  iterating arrays and strings.

- Use EvalExecutable::create() instead of EvalExecutable constructor.
  The constructor is private.

- Reimplement getOwnPropertyDescriptor() in all custom script objects.

- Remove all reimplementations of getPropertyAttributes().
  It doesn't exist in trunk anymore (getOwnPropertyDescriptor() is used
  instead).

- Remove checkDontDelete argument from deleteProperty() reimplementations.
  The purpose of this argument was to support deleting properties
  with attribute Undeletable from C++. But it was quite an invasive
  patch to JavaScriptCore, and it doesn't seem worth it. If this feature
  is really crucial it should be re-done upstream.
  One of the tests needed to be updated so it's not sensitive to the
  C++ undeletability.

- Adapt getOwnPropertyNames() reimplementations to signature change.

- Add missing QScriptObject structure flags, otherwise we don't get all virtual calls.

- Remove our patch for reporting column numbers in the debugger callbacks.
  It was just too intrusive. As with the checkDontDelete issue, this should
  be redone upstream if it's really important. In 4.7, QScriptEngineAgent
  will always report a column number of 1.

Other compilation fixes:

- InternalFunction::name() takes an ExecState* argument, not GlobalData*
- ScopeChain::globalObject is no longer a function but a member variable
- ScopeChainNode constructor takes a GlobalObject argument
- Heap::collect() is called collectAllGarbage()
- JSValue::strictEqual() takes an ExecState* argument
- Debugger::exception() takes a bool hasHandler argument
- Debugger no longer reports column number (we decided to drop that patch from JSC)
- UString doesn't have operator+=(char*)

- Update the autotests to reflect the columnNumber=1 change.

- Add helper class to avoid crashing inside JSC.
  Ever since r52856 in WebKit trunk, this is needed. There are probably a lot of
  other public API functions that need this guard as well, but I'll add them as they
  are discovered.

- Update mkdist-javascriptcore tag, exclude a few more files.

- Set ENABLE_JSC_MULTIPLE_THREADS=0 define on Mac due to r52355 in trunk.

Reviewed-by: Simon Hausmann

7 files changed, 627 insertions, 506 deletions

diff --git a/src/3rdparty/javascriptcore/JavaScriptCore/interpreter/CachedCall.h b/src/3rdparty/javascriptcore/JavaScriptCore/interpreter/CachedCall.h
index b9fa484..eb48a03 100644
--- a/src/3rdparty/javascriptcore/JavaScriptCore/interpreter/CachedCall.h
+++ b/src/3rdparty/javascriptcore/JavaScriptCore/interpreter/CachedCall.h
@@ -38,7 +38,7 @@ namespace JSC {
             : m_valid(false)
             , m_interpreter(callFrame->interpreter())
             , m_exception(exception)
-            , m_globalObjectScope(callFrame, callFrame->globalData().dynamicGlobalObject ? callFrame->globalData().dynamicGlobalObject : function->scope().node()->globalObject())
+            , m_globalObjectScope(callFrame, function->scope().globalObject())
         {
             ASSERT(!function->isHostFunction());
             m_closure = m_interpreter->prepareForRepeatCall(function->jsExecutable(), callFrame, function, argCount, function->scope().node(), exception);
@@ -52,7 +52,14 @@ namespace JSC {
         }
         void setThis(JSValue v) { m_closure.setArgument(0, v); }
         void setArgument(int n, JSValue v) { m_closure.setArgument(n + 1, v); }
-        CallFrame* newCallFrame() { return m_closure.newCallFrame; }
+
+        CallFrame* newCallFrame(ExecState* exec)
+        {
+            CallFrame* callFrame = m_closure.newCallFrame;
+            callFrame->setScopeChain(exec->scopeChain());
+            return callFrame;
+        }
+
         ~CachedCall()
         {
             if (m_valid)
diff --git a/src/3rdparty/javascriptcore/JavaScriptCore/interpreter/CallFrame.h b/src/3rdparty/javascriptcore/JavaScriptCore/interpreter/CallFrame.h
index b04e1c1..6432f99 100644
--- a/src/3rdparty/javascriptcore/JavaScriptCore/interpreter/CallFrame.h
+++ b/src/3rdparty/javascriptcore/JavaScriptCore/interpreter/CallFrame.h
@@ -39,7 +39,11 @@ namespace JSC  {
     public:
         JSObject* callee() const { return this[RegisterFile::Callee].object(); }
         CodeBlock* codeBlock() const { return this[RegisterFile::CodeBlock].Register::codeBlock(); }
-        ScopeChainNode* scopeChain() const { return this[RegisterFile::ScopeChain].Register::scopeChain(); }
+        ScopeChainNode* scopeChain() const
+        {
+            ASSERT(this[RegisterFile::ScopeChain].Register::scopeChain());
+            return this[RegisterFile::ScopeChain].Register::scopeChain();
+        }
         int argumentCount() const { return this[RegisterFile::ArgumentCount].i(); }
 
         JSValue thisValue();
@@ -51,14 +55,14 @@ namespace JSC  {
         // Differs from dynamicGlobalObject() during function calls across web browser frames.
         JSGlobalObject* lexicalGlobalObject() const
         {
-            return scopeChain()->globalObject();
+            return scopeChain()->globalObject;
         }
 
         // Differs from lexicalGlobalObject because this will have DOM window shell rather than
         // the actual DOM window, which can't be "this" for security reasons.
         JSObject* globalThisValue() const
         {
-            return scopeChain()->globalThisObject();
+            return scopeChain()->globalThis;
         }
 
         // FIXME: Elsewhere, we use JSGlobalData* rather than JSGlobalData&.
@@ -66,6 +70,7 @@ namespace JSC  {
         // or a pointer everywhere.
         JSGlobalData& globalData() const
         {
+            ASSERT(scopeChain()->globalData);
             return *scopeChain()->globalData;
         }
 
@@ -105,9 +110,9 @@ namespace JSC  {
         Arguments* optionalCalleeArguments() const { return this[RegisterFile::OptionalCalleeArguments].arguments(); }
         Instruction* returnPC() const { return this[RegisterFile::ReturnPC].vPC(); }
 
-        void setCalleeArguments(JSValue arguments) { this[RegisterFile::OptionalCalleeArguments] = arguments; }
-        void setCallerFrame(CallFrame* callerFrame) { this[RegisterFile::CallerFrame] = callerFrame; }
-        void setScopeChain(ScopeChainNode* scopeChain) { this[RegisterFile::ScopeChain] = scopeChain; }
+        void setCalleeArguments(JSValue arguments) { static_cast<Register*>(this)[RegisterFile::OptionalCalleeArguments] = arguments; }
+        void setCallerFrame(CallFrame* callerFrame) { static_cast<Register*>(this)[RegisterFile::CallerFrame] = callerFrame; }
+        void setScopeChain(ScopeChainNode* scopeChain) { static_cast<Register*>(this)[RegisterFile::ScopeChain] = scopeChain; }
 
         ALWAYS_INLINE void init(CodeBlock* codeBlock, Instruction* vPC, ScopeChainNode* scopeChain,
             CallFrame* callerFrame, int returnValueRegister, int argc, JSObject* callee)
@@ -117,8 +122,8 @@ namespace JSC  {
             setCodeBlock(codeBlock);
             setScopeChain(scopeChain);
             setCallerFrame(callerFrame);
-            this[RegisterFile::ReturnPC] = vPC; // This is either an Instruction* or a pointer into JIT generated code stored as an Instruction*.
-            this[RegisterFile::ReturnValueRegister] = Register::withInt(returnValueRegister);
+            static_cast<Register*>(this)[RegisterFile::ReturnPC] = vPC; // This is either an Instruction* or a pointer into JIT generated code stored as an Instruction*.
+            static_cast<Register*>(this)[RegisterFile::ReturnValueRegister] = Register::withInt(returnValueRegister);
             setArgumentCount(argc); // original argument count (for the sake of the "arguments" object)
             setCallee(callee);
             setCalleeArguments(JSValue());
@@ -135,9 +140,9 @@ namespace JSC  {
         CallFrame* removeHostCallFrameFlag() { return reinterpret_cast<CallFrame*>(reinterpret_cast<intptr_t>(this) & ~HostCallFrameFlag); }
 
     private:
-        void setArgumentCount(int count) { this[RegisterFile::ArgumentCount] = Register::withInt(count); }
-        void setCallee(JSObject* callee) { this[RegisterFile::Callee] = callee; }
-        void setCodeBlock(CodeBlock* codeBlock) { this[RegisterFile::CodeBlock] = codeBlock; }
+        void setArgumentCount(int count) { static_cast<Register*>(this)[RegisterFile::ArgumentCount] = Register::withInt(count); }
+        void setCallee(JSObject* callee) { static_cast<Register*>(this)[RegisterFile::Callee] = callee; }
+        void setCodeBlock(CodeBlock* codeBlock) { static_cast<Register*>(this)[RegisterFile::CodeBlock] = codeBlock; }
 
         static const intptr_t HostCallFrameFlag = 1;
 
diff --git a/src/3rdparty/javascriptcore/JavaScriptCore/interpreter/Interpreter.cpp b/src/3rdparty/javascriptcore/JavaScriptCore/interpreter/Interpreter.cpp
index 4f00b2b..2164b1d 100644
--- a/src/3rdparty/javascriptcore/JavaScriptCore/interpreter/Interpreter.cpp
+++ b/src/3rdparty/javascriptcore/JavaScriptCore/interpreter/Interpreter.cpp
@@ -95,8 +95,8 @@ static int depth(CodeBlock* codeBlock, ScopeChain& sc)
 #if USE(INTERPRETER)
 NEVER_INLINE bool Interpreter::resolve(CallFrame* callFrame, Instruction* vPC, JSValue& exceptionValue)
 {
-    int dst = (vPC + 1)->u.operand;
-    int property = (vPC + 2)->u.operand;
+    int dst = vPC[1].u.operand;
+    int property = vPC[2].u.operand;
 
     ScopeChainNode* scopeChain = callFrame->scopeChain();
     ScopeChainIterator iter = scopeChain->begin();
@@ -125,9 +125,9 @@ NEVER_INLINE bool Interpreter::resolveSkip(CallFrame* callFrame, Instruction* vP
 {
     CodeBlock* codeBlock = callFrame->codeBlock();
 
-    int dst = (vPC + 1)->u.operand;
-    int property = (vPC + 2)->u.operand;
-    int skip = (vPC + 3)->u.operand + codeBlock->needsFullScopeChain();
+    int dst = vPC[1].u.operand;
+    int property = vPC[2].u.operand;
+    int skip = vPC[3].u.operand + codeBlock->needsFullScopeChain();
 
     ScopeChainNode* scopeChain = callFrame->scopeChain();
     ScopeChainIterator iter = scopeChain->begin();
@@ -156,12 +156,12 @@ NEVER_INLINE bool Interpreter::resolveSkip(CallFrame* callFrame, Instruction* vP
 
 NEVER_INLINE bool Interpreter::resolveGlobal(CallFrame* callFrame, Instruction* vPC, JSValue& exceptionValue)
 {
-    int dst = (vPC + 1)->u.operand;
-    JSGlobalObject* globalObject = static_cast<JSGlobalObject*>((vPC + 2)->u.jsCell);
+    int dst = vPC[1].u.operand;
+    JSGlobalObject* globalObject = static_cast<JSGlobalObject*>(vPC[2].u.jsCell);
     ASSERT(globalObject->isGlobalObject());
-    int property = (vPC + 3)->u.operand;
-    Structure* structure = (vPC + 4)->u.structure;
-    int offset = (vPC + 5)->u.operand;
+    int property = vPC[3].u.operand;
+    Structure* structure = vPC[4].u.structure;
+    int offset = vPC[5].u.operand;
 
     if (structure == globalObject->structure()) {
         callFrame->r(dst) = JSValue(globalObject->getDirectOffset(offset));
@@ -196,16 +196,16 @@ NEVER_INLINE bool Interpreter::resolveGlobal(CallFrame* callFrame, Instruction*
 
 NEVER_INLINE void Interpreter::resolveBase(CallFrame* callFrame, Instruction* vPC)
 {
-    int dst = (vPC + 1)->u.operand;
-    int property = (vPC + 2)->u.operand;
+    int dst = vPC[1].u.operand;
+    int property = vPC[2].u.operand;
     callFrame->r(dst) = JSValue(JSC::resolveBase(callFrame, callFrame->codeBlock()->identifier(property), callFrame->scopeChain()));
 }
 
 NEVER_INLINE bool Interpreter::resolveBaseAndProperty(CallFrame* callFrame, Instruction* vPC, JSValue& exceptionValue)
 {
-    int baseDst = (vPC + 1)->u.operand;
-    int propDst = (vPC + 2)->u.operand;
-    int property = (vPC + 3)->u.operand;
+    int baseDst = vPC[1].u.operand;
+    int propDst = vPC[2].u.operand;
+    int property = vPC[3].u.operand;
 
     ScopeChainNode* scopeChain = callFrame->scopeChain();
     ScopeChainIterator iter = scopeChain->begin();
@@ -237,51 +237,6 @@ NEVER_INLINE bool Interpreter::resolveBaseAndProperty(CallFrame* callFrame, Inst
     return false;
 }
 
-NEVER_INLINE bool Interpreter::resolveBaseAndFunc(CallFrame* callFrame, Instruction* vPC, JSValue& exceptionValue)
-{
-    int baseDst = (vPC + 1)->u.operand;
-    int funcDst = (vPC + 2)->u.operand;
-    int property = (vPC + 3)->u.operand;
-
-    ScopeChainNode* scopeChain = callFrame->scopeChain();
-    ScopeChainIterator iter = scopeChain->begin();
-    ScopeChainIterator end = scopeChain->end();
-
-    // FIXME: add scopeDepthIsZero optimization
-
-    ASSERT(iter != end);
-
-    CodeBlock* codeBlock = callFrame->codeBlock();
-    Identifier& ident = codeBlock->identifier(property);
-    JSObject* base;
-    do {
-        base = *iter;
-        PropertySlot slot(base);
-        if (base->getPropertySlot(callFrame, ident, slot)) {            
-            // ECMA 11.2.3 says that if we hit an activation the this value should be null.
-            // However, section 10.2.3 says that in the case where the value provided
-            // by the caller is null, the global object should be used. It also says
-            // that the section does not apply to internal functions, but for simplicity
-            // of implementation we use the global object anyway here. This guarantees
-            // that in host objects you always get a valid object for this.
-            // We also handle wrapper substitution for the global object at the same time.
-            JSObject* thisObj = base->toThisObject(callFrame);
-            JSValue result = slot.getValue(callFrame, ident);
-            exceptionValue = callFrame->globalData().exception;
-            if (exceptionValue)
-                return false;
-
-            callFrame->r(baseDst) = JSValue(thisObj);
-            callFrame->r(funcDst) = JSValue(result);
-            return true;
-        }
-        ++iter;
-    } while (iter != end);
-
-    exceptionValue = createUndefinedVariableError(callFrame, ident, vPC - codeBlock->instructions().begin(), codeBlock);
-    return false;
-}
-
 #endif // USE(INTERPRETER)
 
 ALWAYS_INLINE CallFrame* Interpreter::slideRegisterWindowForCall(CodeBlock* newCodeBlock, RegisterFile* registerFile, CallFrame* callFrame, size_t registerOffset, int argc)
@@ -349,7 +304,7 @@ NEVER_INLINE JSValue Interpreter::callEval(CallFrame* callFrame, RegisterFile* r
     if (!program.isString())
         return program;
 
-    UString programSource = asString(program)->value();
+    UString programSource = asString(program)->value(callFrame);
 
     LiteralParser preparser(callFrame, programSource, LiteralParser::NonStrictJSON);
     if (JSValue parsedObject = preparser.tryLiteralParse())
@@ -367,10 +322,19 @@ NEVER_INLINE JSValue Interpreter::callEval(CallFrame* callFrame, RegisterFile* r
 }
 
 Interpreter::Interpreter()
-    : m_sampler(0)
+    : m_sampleEntryDepth(0)
     , m_reentryDepth(0)
 {
+#if HAVE(COMPUTED_GOTO)
     privateExecute(InitializeAndReturn, 0, 0, 0);
+
+    for (int i = 0; i < numOpcodeIDs; ++i)
+        m_opcodeIDTable.add(m_opcodeTable[i], static_cast<OpcodeID>(i));
+#endif // HAVE(COMPUTED_GOTO)
+
+#if ENABLE(OPCODE_SAMPLING)
+    enableSampler();
+#endif
 }
 
 #ifndef NDEBUG
@@ -389,7 +353,7 @@ void Interpreter::dumpRegisters(CallFrame* callFrame)
     printf("-----------------------------------------------------------------------------\n");
 
     CodeBlock* codeBlock = callFrame->codeBlock();
-    RegisterFile* registerFile = &callFrame->scopeChain()->globalObject()->globalData()->interpreter->registerFile();
+    RegisterFile* registerFile = &callFrame->scopeChain()->globalObject->globalData()->interpreter->registerFile();
     const Register* it;
     const Register* end;
     JSValue v;
@@ -577,7 +541,8 @@ NEVER_INLINE HandlerInfo* Interpreter::throwException(CallFrame*& callFrame, JSV
     Debugger* debugger = callFrame->dynamicGlobalObject()->debugger();
     if (debugger) {
         DebuggerCallFrame debuggerCallFrame(callFrame, exceptionValue);
-        debugger->exception(debuggerCallFrame, codeBlock->ownerExecutable()->sourceID(), codeBlock->lineNumberForBytecodeOffset(callFrame, bytecodeOffset));
+        bool hasHandler = codeBlock->handlerForBytecodeOffset(bytecodeOffset);
+        debugger->exception(debuggerCallFrame, codeBlock->ownerExecutable()->sourceID(), codeBlock->lineNumberForBytecodeOffset(callFrame, bytecodeOffset), hasHandler);
     }
 
     // If we throw in the middle of a call instruction, we need to notify
@@ -587,7 +552,7 @@ NEVER_INLINE HandlerInfo* Interpreter::throwException(CallFrame*& callFrame, JSV
 #if !ENABLE(JIT)
         if (isCallBytecode(codeBlock->instructions()[bytecodeOffset].u.opcode))
             profiler->didExecute(callFrame, callFrame->r(codeBlock->instructions()[bytecodeOffset + 2].u.operand).jsValue());
-        else if (codeBlock->instructions()[bytecodeOffset + 8].u.opcode == getOpcode(op_construct))
+        else if (codeBlock->instructions().size() > (bytecodeOffset + 8) && codeBlock->instructions()[bytecodeOffset + 8].u.opcode == getOpcode(op_construct))
             profiler->didExecute(callFrame, callFrame->r(codeBlock->instructions()[bytecodeOffset + 10].u.operand).jsValue());
 #else
         int functionRegisterIndex;
@@ -659,7 +624,7 @@ JSValue Interpreter::execute(ProgramExecutable* program, CallFrame* callFrame, S
         return jsNull();
     }
 
-    DynamicGlobalObjectScope globalObjectScope(callFrame, scopeChain->globalObject());
+    DynamicGlobalObjectScope globalObjectScope(callFrame, scopeChain->globalObject);
 
     JSGlobalObject* lastGlobalObject = m_registerFile.globalObject();
     JSGlobalObject* globalObject = callFrame->dynamicGlobalObject();
@@ -678,7 +643,7 @@ JSValue Interpreter::execute(ProgramExecutable* program, CallFrame* callFrame, S
 
     JSValue result;
     {
-        SamplingTool::CallRecord callRecord(m_sampler);
+        SamplingTool::CallRecord callRecord(m_sampler.get());
 
         m_reentryDepth++;
 #if ENABLE(JIT)
@@ -719,7 +684,7 @@ JSValue Interpreter::execute(FunctionExecutable* functionExecutable, CallFrame*
         return jsNull();
     }
 
-    DynamicGlobalObjectScope globalObjectScope(callFrame, callFrame->globalData().dynamicGlobalObject ? callFrame->globalData().dynamicGlobalObject : scopeChain->globalObject());
+    DynamicGlobalObjectScope globalObjectScope(callFrame, scopeChain->globalObject);
 
     CallFrame* newCallFrame = CallFrame::create(oldEnd);
     size_t dst = 0;
@@ -744,7 +709,7 @@ JSValue Interpreter::execute(FunctionExecutable* functionExecutable, CallFrame*
 
     JSValue result;
     {
-        SamplingTool::CallRecord callRecord(m_sampler);
+        SamplingTool::CallRecord callRecord(m_sampler.get());
 
         m_reentryDepth++;
 #if ENABLE(JIT)
@@ -812,7 +777,7 @@ JSValue Interpreter::execute(CallFrameClosure& closure, JSValue* exception)
     
     JSValue result;
     {
-        SamplingTool::CallRecord callRecord(m_sampler);
+        SamplingTool::CallRecord callRecord(m_sampler.get());
         
         m_reentryDepth++;
 #if ENABLE(JIT)
@@ -849,7 +814,7 @@ JSValue Interpreter::execute(EvalExecutable* eval, CallFrame* callFrame, JSObjec
         }
     }
 
-    DynamicGlobalObjectScope globalObjectScope(callFrame, callFrame->globalData().dynamicGlobalObject ? callFrame->globalData().dynamicGlobalObject : scopeChain->globalObject());
+    DynamicGlobalObjectScope globalObjectScope(callFrame, scopeChain->globalObject);
 
     EvalCodeBlock* codeBlock = &eval->bytecode(callFrame, scopeChain);
 
@@ -914,7 +879,7 @@ JSValue Interpreter::execute(EvalExecutable* eval, CallFrame* callFrame, JSObjec
 
     JSValue result;
     {
-        SamplingTool::CallRecord callRecord(m_sampler);
+        SamplingTool::CallRecord callRecord(m_sampler.get());
 
         m_reentryDepth++;
 #if ENABLE(JIT)
@@ -932,7 +897,7 @@ JSValue Interpreter::execute(EvalExecutable* eval, CallFrame* callFrame, JSObjec
     return result;
 }
 
-NEVER_INLINE void Interpreter::debug(CallFrame* callFrame, DebugHookID debugHookID, int firstLine, int lastLine, int column)
+NEVER_INLINE void Interpreter::debug(CallFrame* callFrame, DebugHookID debugHookID, int firstLine, int lastLine)
 {
     Debugger* debugger = callFrame->dynamicGlobalObject()->debugger();
     if (!debugger)
@@ -946,7 +911,7 @@ NEVER_INLINE void Interpreter::debug(CallFrame* callFrame, DebugHookID debugHook
             debugger->returnEvent(callFrame, callFrame->codeBlock()->ownerExecutable()->sourceID(), lastLine);
             return;
         case WillExecuteStatement:
-            debugger->atStatement(callFrame, callFrame->codeBlock()->ownerExecutable()->sourceID(), firstLine, column);
+            debugger->atStatement(callFrame, callFrame->codeBlock()->ownerExecutable()->sourceID(), firstLine);
             return;
         case WillExecuteProgram:
             debugger->willExecuteProgram(callFrame, callFrame->codeBlock()->ownerExecutable()->sourceID(), firstLine);
@@ -955,7 +920,7 @@ NEVER_INLINE void Interpreter::debug(CallFrame* callFrame, DebugHookID debugHook
             debugger->didExecuteProgram(callFrame, callFrame->codeBlock()->ownerExecutable()->sourceID(), lastLine);
             return;
         case DidReachBreakpoint:
-            debugger->didReachBreakpoint(callFrame, callFrame->codeBlock()->ownerExecutable()->sourceID(), lastLine, column);
+            debugger->didReachBreakpoint(callFrame, callFrame->codeBlock()->ownerExecutable()->sourceID(), lastLine);
             return;
     }
 }
@@ -963,10 +928,10 @@ NEVER_INLINE void Interpreter::debug(CallFrame* callFrame, DebugHookID debugHook
 #if USE(INTERPRETER)
 NEVER_INLINE ScopeChainNode* Interpreter::createExceptionScope(CallFrame* callFrame, const Instruction* vPC)
 {
-    int dst = (++vPC)->u.operand;
+    int dst = vPC[1].u.operand;
     CodeBlock* codeBlock = callFrame->codeBlock();
-    Identifier& property = codeBlock->identifier((++vPC)->u.operand);
-    JSValue value = callFrame->r((++vPC)->u.operand).jsValue();
+    Identifier& property = codeBlock->identifier(vPC[2].u.operand);
+    JSValue value = callFrame->r(vPC[3].u.operand).jsValue();
     JSObject* scope = new (callFrame) JSStaticScopeObject(callFrame, property, value, DontDelete);
     callFrame->r(dst) = JSValue(scope);
 
@@ -1018,22 +983,20 @@ NEVER_INLINE void Interpreter::tryCachePutByID(CallFrame* callFrame, CodeBlock*
         return;
     }
 
-    StructureChain* protoChain = structure->prototypeChain(callFrame);
-    if (!protoChain->isCacheable()) {
-        vPC[0] = getOpcode(op_put_by_id_generic);
-        return;
-    }
-
     // Structure transition, cache transition info
     if (slot.type() == PutPropertySlot::NewProperty) {
         if (structure->isDictionary()) {
             vPC[0] = getOpcode(op_put_by_id_generic);
             return;
         }
+
+        // put_by_id_transition checks the prototype chain for setters.
+        normalizePrototypeChain(callFrame, baseCell);
+
         vPC[0] = getOpcode(op_put_by_id_transition);
         vPC[4] = structure->previousID();
         vPC[5] = structure;
-        vPC[6] = protoChain;
+        vPC[6] = structure->prototypeChain(callFrame);
         vPC[7] = slot.cachedOffset();
         codeBlock->refStructures(vPC);
         return;
@@ -1111,41 +1074,46 @@ NEVER_INLINE void Interpreter::tryCacheGetByID(CallFrame* callFrame, CodeBlock*
         return;
     }
 
+    if (structure->isDictionary()) {
+        vPC[0] = getOpcode(op_get_by_id_generic);
+        return;
+    }
+
     if (slot.slotBase() == structure->prototypeForLookup(callFrame)) {
         ASSERT(slot.slotBase().isObject());
 
         JSObject* baseObject = asObject(slot.slotBase());
+        size_t offset = slot.cachedOffset();
 
         // Since we're accessing a prototype in a loop, it's a good bet that it
         // should not be treated as a dictionary.
-        if (baseObject->structure()->isDictionary())
-            baseObject->setStructure(Structure::fromDictionaryTransition(baseObject->structure()));
+        if (baseObject->structure()->isDictionary()) {
+            baseObject->flattenDictionaryObject();
+            offset = baseObject->structure()->get(propertyName);
+        }
+
+        ASSERT(!baseObject->structure()->isUncacheableDictionary());
 
         vPC[0] = getOpcode(op_get_by_id_proto);
         vPC[5] = baseObject->structure();
-        vPC[6] = slot.cachedOffset();
+        vPC[6] = offset;
 
         codeBlock->refStructures(vPC);
         return;
     }
 
-    size_t count = countPrototypeChainEntriesAndCheckForProxies(callFrame, baseValue, slot);
+    size_t offset = slot.cachedOffset();
+    size_t count = normalizePrototypeChain(callFrame, baseValue, slot.slotBase(), propertyName, offset);
     if (!count) {
         vPC[0] = getOpcode(op_get_by_id_generic);
         return;
     }
 
-    StructureChain* protoChain = structure->prototypeChain(callFrame);
-    if (!protoChain->isCacheable()) {
-        vPC[0] = getOpcode(op_get_by_id_generic);
-        return;
-    }
-
     vPC[0] = getOpcode(op_get_by_id_chain);
     vPC[4] = structure;
-    vPC[5] = protoChain;
+    vPC[5] = structure->prototypeChain(callFrame);
     vPC[6] = count;
-    vPC[7] = slot.cachedOffset();
+    vPC[7] = offset;
     codeBlock->refStructures(vPC);
 }
 
@@ -1162,16 +1130,13 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
 {
     // One-time initialization of our address tables. We have to put this code
     // here because our labels are only in scope inside this function.
-    if (flag == InitializeAndReturn) {
+    if (UNLIKELY(flag == InitializeAndReturn)) {
         #if HAVE(COMPUTED_GOTO)
-            #define ADD_BYTECODE(id, length) m_opcodeTable[id] = &&id;
-                FOR_EACH_OPCODE_ID(ADD_BYTECODE);
-            #undef ADD_BYTECODE
-
-            #define ADD_OPCODE_ID(id, length) m_opcodeIDTable.add(&&id, id);
-                FOR_EACH_OPCODE_ID(ADD_OPCODE_ID);
-            #undef ADD_OPCODE_ID
-            ASSERT(m_opcodeIDTable.size() == numOpcodeIDs);
+            #define LIST_OPCODE_LABEL(id, length) &&id,
+                static Opcode labels[] = { FOR_EACH_OPCODE_ID(LIST_OPCODE_LABEL) };
+                for (size_t i = 0; i < sizeof(labels) / sizeof(Opcode); ++i)
+                    m_opcodeTable[i] = labels[i];
+            #undef LIST_OPCODE_LABEL
         #endif // HAVE(COMPUTED_GOTO)
         return JSValue();
     }
@@ -1249,10 +1214,10 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
            Constructs a new empty Object instance using the original
            constructor, and puts the result in register dst.
         */
-        int dst = (++vPC)->u.operand;
+        int dst = vPC[1].u.operand;
         callFrame->r(dst) = JSValue(constructEmptyObject(callFrame));
 
-        ++vPC;
+        vPC += OPCODE_LENGTH(op_new_object);
         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_new_array) {
@@ -1263,13 +1228,13 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
            The array will contain argCount elements with values
            taken from registers starting at register firstArg.
         */
-        int dst = (++vPC)->u.operand;
-        int firstArg = (++vPC)->u.operand;
-        int argCount = (++vPC)->u.operand;
+        int dst = vPC[1].u.operand;
+        int firstArg = vPC[2].u.operand;
+        int argCount = vPC[3].u.operand;
         ArgList args(callFrame->registers() + firstArg, argCount);
         callFrame->r(dst) = JSValue(constructArray(callFrame, args));
 
-        ++vPC;
+        vPC += OPCODE_LENGTH(op_new_array);
         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_new_regexp) {
@@ -1279,11 +1244,11 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
            constructor from regexp regExp, and puts the result in
            register dst.
         */
-        int dst = (++vPC)->u.operand;
-        int regExp = (++vPC)->u.operand;
-        callFrame->r(dst) = JSValue(new (globalData) RegExpObject(callFrame->scopeChain()->globalObject()->regExpStructure(), callFrame->codeBlock()->regexp(regExp)));
+        int dst = vPC[1].u.operand;
+        int regExp = vPC[2].u.operand;
+        callFrame->r(dst) = JSValue(new (globalData) RegExpObject(callFrame->scopeChain()->globalObject->regExpStructure(), callFrame->codeBlock()->regexp(regExp)));
 
-        ++vPC;
+        vPC += OPCODE_LENGTH(op_new_regexp);
         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_mov) {
@@ -1291,11 +1256,11 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
 
            Copies register src to register dst.
         */
-        int dst = (++vPC)->u.operand;
-        int src = (++vPC)->u.operand;
+        int dst = vPC[1].u.operand;
+        int src = vPC[2].u.operand;
         callFrame->r(dst) = callFrame->r(src);
 
-        ++vPC;
+        vPC += OPCODE_LENGTH(op_mov);
         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_eq) {
@@ -1305,9 +1270,9 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
            as with the ECMAScript '==' operator, and puts the result
            as a boolean in register dst.
         */
-        int dst = (++vPC)->u.operand;
-        JSValue src1 = callFrame->r((++vPC)->u.operand).jsValue();
-        JSValue src2 = callFrame->r((++vPC)->u.operand).jsValue();
+        int dst = vPC[1].u.operand;
+        JSValue src1 = callFrame->r(vPC[2].u.operand).jsValue();
+        JSValue src2 = callFrame->r(vPC[3].u.operand).jsValue();
         if (src1.isInt32() && src2.isInt32())
             callFrame->r(dst) = jsBoolean(src1.asInt32() == src2.asInt32());
         else {
@@ -1316,7 +1281,7 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
             callFrame->r(dst) = result;
         }
 
-        ++vPC;
+        vPC += OPCODE_LENGTH(op_eq);
         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_eq_null) {
@@ -1325,17 +1290,17 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
            Checks whether register src is null, as with the ECMAScript '!='
            operator, and puts the result as a boolean in register dst.
         */
-        int dst = (++vPC)->u.operand;
-        JSValue src = callFrame->r((++vPC)->u.operand).jsValue();
+        int dst = vPC[1].u.operand;
+        JSValue src = callFrame->r(vPC[2].u.operand).jsValue();
 
         if (src.isUndefinedOrNull()) {
             callFrame->r(dst) = jsBoolean(true);
-            ++vPC;
+            vPC += OPCODE_LENGTH(op_eq_null);
             NEXT_INSTRUCTION();
         }
         
         callFrame->r(dst) = jsBoolean(src.isCell() && src.asCell()->structure()->typeInfo().masqueradesAsUndefined());
-        ++vPC;
+        vPC += OPCODE_LENGTH(op_eq_null);
         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_neq) {
@@ -1345,9 +1310,9 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
            equal, as with the ECMAScript '!=' operator, and puts the
            result as a boolean in register dst.
         */
-        int dst = (++vPC)->u.operand;
-        JSValue src1 = callFrame->r((++vPC)->u.operand).jsValue();
-        JSValue src2 = callFrame->r((++vPC)->u.operand).jsValue();
+        int dst = vPC[1].u.operand;
+        JSValue src1 = callFrame->r(vPC[2].u.operand).jsValue();
+        JSValue src2 = callFrame->r(vPC[3].u.operand).jsValue();
         if (src1.isInt32() && src2.isInt32())
             callFrame->r(dst) = jsBoolean(src1.asInt32() != src2.asInt32());
         else {
@@ -1356,7 +1321,7 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
             callFrame->r(dst) = result;
         }
 
-        ++vPC;
+        vPC += OPCODE_LENGTH(op_neq);
         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_neq_null) {
@@ -1365,17 +1330,17 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
            Checks whether register src is not null, as with the ECMAScript '!='
            operator, and puts the result as a boolean in register dst.
         */
-        int dst = (++vPC)->u.operand;
-        JSValue src = callFrame->r((++vPC)->u.operand).jsValue();
+        int dst = vPC[1].u.operand;
+        JSValue src = callFrame->r(vPC[2].u.operand).jsValue();
 
         if (src.isUndefinedOrNull()) {
             callFrame->r(dst) = jsBoolean(false);
-            ++vPC;
+            vPC += OPCODE_LENGTH(op_neq_null);
             NEXT_INSTRUCTION();
         }
         
         callFrame->r(dst) = jsBoolean(!src.isCell() || !asCell(src)->structure()->typeInfo().masqueradesAsUndefined());
-        ++vPC;
+        vPC += OPCODE_LENGTH(op_neq_null);
         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_stricteq) {
@@ -1385,12 +1350,12 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
            equal, as with the ECMAScript '===' operator, and puts the
            result as a boolean in register dst.
         */
-        int dst = (++vPC)->u.operand;
-        JSValue src1 = callFrame->r((++vPC)->u.operand).jsValue();
-        JSValue src2 = callFrame->r((++vPC)->u.operand).jsValue();
-        callFrame->r(dst) = jsBoolean(JSValue::strictEqual(src1, src2));
+        int dst = vPC[1].u.operand;
+        JSValue src1 = callFrame->r(vPC[2].u.operand).jsValue();
+        JSValue src2 = callFrame->r(vPC[3].u.operand).jsValue();
+        callFrame->r(dst) = jsBoolean(JSValue::strictEqual(callFrame, src1, src2));
 
-        ++vPC;
+        vPC += OPCODE_LENGTH(op_stricteq);
         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_nstricteq) {
@@ -1400,12 +1365,12 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
            strictly equal, as with the ECMAScript '!==' operator, and
            puts the result as a boolean in register dst.
         */
-        int dst = (++vPC)->u.operand;
-        JSValue src1 = callFrame->r((++vPC)->u.operand).jsValue();
-        JSValue src2 = callFrame->r((++vPC)->u.operand).jsValue();
-        callFrame->r(dst) = jsBoolean(!JSValue::strictEqual(src1, src2));
+        int dst = vPC[1].u.operand;
+        JSValue src1 = callFrame->r(vPC[2].u.operand).jsValue();
+        JSValue src2 = callFrame->r(vPC[3].u.operand).jsValue();
+        callFrame->r(dst) = jsBoolean(!JSValue::strictEqual(callFrame, src1, src2));
 
-        ++vPC;
+        vPC += OPCODE_LENGTH(op_nstricteq);
         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_less) {
@@ -1415,14 +1380,14 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
            with the ECMAScript '<' operator, and puts the result as
            a boolean in register dst.
         */
-        int dst = (++vPC)->u.operand;
-        JSValue src1 = callFrame->r((++vPC)->u.operand).jsValue();
-        JSValue src2 = callFrame->r((++vPC)->u.operand).jsValue();
+        int dst = vPC[1].u.operand;
+        JSValue src1 = callFrame->r(vPC[2].u.operand).jsValue();
+        JSValue src2 = callFrame->r(vPC[3].u.operand).jsValue();
         JSValue result = jsBoolean(jsLess(callFrame, src1, src2));
         CHECK_FOR_EXCEPTION();
         callFrame->r(dst) = result;
 
-        ++vPC;
+        vPC += OPCODE_LENGTH(op_less);
         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_lesseq) {
@@ -1432,14 +1397,14 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
            register src2, as with the ECMAScript '<=' operator, and
            puts the result as a boolean in register dst.
         */
-        int dst = (++vPC)->u.operand;
-        JSValue src1 = callFrame->r((++vPC)->u.operand).jsValue();
-        JSValue src2 = callFrame->r((++vPC)->u.operand).jsValue();
+        int dst = vPC[1].u.operand;
+        JSValue src1 = callFrame->r(vPC[2].u.operand).jsValue();
+        JSValue src2 = callFrame->r(vPC[3].u.operand).jsValue();
         JSValue result = jsBoolean(jsLessEq(callFrame, src1, src2));
         CHECK_FOR_EXCEPTION();
         callFrame->r(dst) = result;
 
-        ++vPC;
+        vPC += OPCODE_LENGTH(op_lesseq);
         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_pre_inc) {
@@ -1448,7 +1413,7 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
            Converts register srcDst to number, adds one, and puts the result
            back in register srcDst.
         */
-        int srcDst = (++vPC)->u.operand;
+        int srcDst = vPC[1].u.operand;
         JSValue v = callFrame->r(srcDst).jsValue();
         if (v.isInt32() && v.asInt32() < INT_MAX)
             callFrame->r(srcDst) = jsNumber(callFrame, v.asInt32() + 1);
@@ -1458,7 +1423,7 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
             callFrame->r(srcDst) = result;
         }
 
-        ++vPC;
+        vPC += OPCODE_LENGTH(op_pre_inc);
         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_pre_dec) {
@@ -1467,7 +1432,7 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
            Converts register srcDst to number, subtracts one, and puts the result
            back in register srcDst.
         */
-        int srcDst = (++vPC)->u.operand;
+        int srcDst = vPC[1].u.operand;
         JSValue v = callFrame->r(srcDst).jsValue();
         if (v.isInt32() && v.asInt32() > INT_MIN)
             callFrame->r(srcDst) = jsNumber(callFrame, v.asInt32() - 1);
@@ -1477,7 +1442,7 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
             callFrame->r(srcDst) = result;
         }
 
-        ++vPC;
+        vPC += OPCODE_LENGTH(op_pre_dec);
         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_post_inc) {
@@ -1487,8 +1452,8 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
            written to register dst, and the number plus one is written
            back to register srcDst.
         */
-        int dst = (++vPC)->u.operand;
-        int srcDst = (++vPC)->u.operand;
+        int dst = vPC[1].u.operand;
+        int srcDst = vPC[2].u.operand;
         JSValue v = callFrame->r(srcDst).jsValue();
         if (v.isInt32() && v.asInt32() < INT_MAX) {
             callFrame->r(srcDst) = jsNumber(callFrame, v.asInt32() + 1);
@@ -1500,7 +1465,7 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
             callFrame->r(dst) = number;
         }
 
-        ++vPC;
+        vPC += OPCODE_LENGTH(op_post_inc);
         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_post_dec) {
@@ -1510,8 +1475,8 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
            written to register dst, and the number minus one is written
            back to register srcDst.
         */
-        int dst = (++vPC)->u.operand;
-        int srcDst = (++vPC)->u.operand;
+        int dst = vPC[1].u.operand;
+        int srcDst = vPC[2].u.operand;
         JSValue v = callFrame->r(srcDst).jsValue();
         if (v.isInt32() && v.asInt32() > INT_MIN) {
             callFrame->r(srcDst) = jsNumber(callFrame, v.asInt32() - 1);
@@ -1523,7 +1488,7 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
             callFrame->r(dst) = number;
         }
 
-        ++vPC;
+        vPC += OPCODE_LENGTH(op_post_dec);
         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_to_jsnumber) {
@@ -1532,8 +1497,8 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
            Converts register src to number, and puts the result
            in register dst.
         */
-        int dst = (++vPC)->u.operand;
-        int src = (++vPC)->u.operand;
+        int dst = vPC[1].u.operand;
+        int src = vPC[2].u.operand;
 
         JSValue srcVal = callFrame->r(src).jsValue();
 
@@ -1545,7 +1510,7 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
             callFrame->r(dst) = result;
         }
 
-        ++vPC;
+        vPC += OPCODE_LENGTH(op_to_jsnumber);
         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_negate) {
@@ -1554,8 +1519,8 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
            Converts register src to number, negates it, and puts the
            result in register dst.
         */
-        int dst = (++vPC)->u.operand;
-        JSValue src = callFrame->r((++vPC)->u.operand).jsValue();
+        int dst = vPC[1].u.operand;
+        JSValue src = callFrame->r(vPC[2].u.operand).jsValue();
         if (src.isInt32() && src.asInt32())
             callFrame->r(dst) = jsNumber(callFrame, -src.asInt32());
         else {
@@ -1564,7 +1529,7 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
             callFrame->r(dst) = result;
         }
 
-        ++vPC;
+        vPC += OPCODE_LENGTH(op_negate);
         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_add) {
@@ -1574,17 +1539,17 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
            in register dst. (JS add may be string concatenation or
            numeric add, depending on the types of the operands.)
         */
-        int dst = (++vPC)->u.operand;
-        JSValue src1 = callFrame->r((++vPC)->u.operand).jsValue();
-        JSValue src2 = callFrame->r((++vPC)->u.operand).jsValue();
-        if (src1.isInt32() && src2.isInt32() && !(src1.asInt32() | src2.asInt32() & 0xc0000000)) // no overflow
+        int dst = vPC[1].u.operand;
+        JSValue src1 = callFrame->r(vPC[2].u.operand).jsValue();
+        JSValue src2 = callFrame->r(vPC[3].u.operand).jsValue();
+        if (src1.isInt32() && src2.isInt32() && !(src1.asInt32() | (src2.asInt32() & 0xc0000000))) // no overflow
             callFrame->r(dst) = jsNumber(callFrame, src1.asInt32() + src2.asInt32());
         else {
             JSValue result = jsAdd(callFrame, src1, src2);
             CHECK_FOR_EXCEPTION();
             callFrame->r(dst) = result;
         }
-        vPC += 2;
+        vPC += OPCODE_LENGTH(op_add);
         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_mul) {
@@ -1593,9 +1558,9 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
            Multiplies register src1 and register src2 (converted to
            numbers), and puts the product in register dst.
         */
-        int dst = (++vPC)->u.operand;
-        JSValue src1 = callFrame->r((++vPC)->u.operand).jsValue();
-        JSValue src2 = callFrame->r((++vPC)->u.operand).jsValue();
+        int dst = vPC[1].u.operand;
+        JSValue src1 = callFrame->r(vPC[2].u.operand).jsValue();
+        JSValue src2 = callFrame->r(vPC[3].u.operand).jsValue();
         if (src1.isInt32() && src2.isInt32() && !(src1.asInt32() | src2.asInt32() >> 15)) // no overflow
                 callFrame->r(dst) = jsNumber(callFrame, src1.asInt32() * src2.asInt32());
         else {
@@ -1604,7 +1569,7 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
             callFrame->r(dst) = result;
         }
 
-        vPC += 2;
+        vPC += OPCODE_LENGTH(op_mul);
         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_div) {
@@ -1614,15 +1579,15 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
            register divisor (converted to number), and puts the
            quotient in register dst.
         */
-        int dst = (++vPC)->u.operand;
-        JSValue dividend = callFrame->r((++vPC)->u.operand).jsValue();
-        JSValue divisor = callFrame->r((++vPC)->u.operand).jsValue();
+        int dst = vPC[1].u.operand;
+        JSValue dividend = callFrame->r(vPC[2].u.operand).jsValue();
+        JSValue divisor = callFrame->r(vPC[3].u.operand).jsValue();
 
         JSValue result = jsNumber(callFrame, dividend.toNumber(callFrame) / divisor.toNumber(callFrame));
         CHECK_FOR_EXCEPTION();
         callFrame->r(dst) = result;
 
-        vPC += 2;
+        vPC += OPCODE_LENGTH(op_div);
         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_mod) {
@@ -1632,15 +1597,15 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
            register divisor (converted to number), and puts the
            remainder in register dst.
         */
-        int dst = (++vPC)->u.operand;
-        JSValue dividend = callFrame->r((++vPC)->u.operand).jsValue();
-        JSValue divisor = callFrame->r((++vPC)->u.operand).jsValue();
+        int dst = vPC[1].u.operand;
+        JSValue dividend = callFrame->r(vPC[2].u.operand).jsValue();
+        JSValue divisor = callFrame->r(vPC[3].u.operand).jsValue();
 
         if (dividend.isInt32() && divisor.isInt32() && divisor.asInt32() != 0) {
             JSValue result = jsNumber(callFrame, dividend.asInt32() % divisor.asInt32());
             ASSERT(result);
             callFrame->r(dst) = result;
-            ++vPC;
+            vPC += OPCODE_LENGTH(op_mod);
             NEXT_INSTRUCTION();
         }
 
@@ -1651,7 +1616,7 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
         JSValue result = jsNumber(callFrame, fmod(d1, d2));
         CHECK_FOR_EXCEPTION();
         callFrame->r(dst) = result;
-        ++vPC;
+        vPC += OPCODE_LENGTH(op_mod);
         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_sub) {
@@ -1661,17 +1626,17 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
            src1 (converted to number), and puts the difference in
            register dst.
         */
-        int dst = (++vPC)->u.operand;
-        JSValue src1 = callFrame->r((++vPC)->u.operand).jsValue();
-        JSValue src2 = callFrame->r((++vPC)->u.operand).jsValue();
-        if (src1.isInt32() && src2.isInt32() && !(src1.asInt32() | src2.asInt32() & 0xc0000000)) // no overflow
+        int dst = vPC[1].u.operand;
+        JSValue src1 = callFrame->r(vPC[2].u.operand).jsValue();
+        JSValue src2 = callFrame->r(vPC[3].u.operand).jsValue();
+        if (src1.isInt32() && src2.isInt32() && !(src1.asInt32() | (src2.asInt32() & 0xc0000000))) // no overflow
             callFrame->r(dst) = jsNumber(callFrame, src1.asInt32() - src2.asInt32());
         else {
             JSValue result = jsNumber(callFrame, src1.toNumber(callFrame) - src2.toNumber(callFrame));
             CHECK_FOR_EXCEPTION();
             callFrame->r(dst) = result;
         }
-        vPC += 2;
+        vPC += OPCODE_LENGTH(op_sub);
         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_lshift) {
@@ -1681,9 +1646,9 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
            register shift (converted to uint32), and puts the result
            in register dst.
         */
-        int dst = (++vPC)->u.operand;
-        JSValue val = callFrame->r((++vPC)->u.operand).jsValue();
-        JSValue shift = callFrame->r((++vPC)->u.operand).jsValue();
+        int dst = vPC[1].u.operand;
+        JSValue val = callFrame->r(vPC[2].u.operand).jsValue();
+        JSValue shift = callFrame->r(vPC[3].u.operand).jsValue();
 
         if (val.isInt32() && shift.isInt32())
             callFrame->r(dst) = jsNumber(callFrame, val.asInt32() << (shift.asInt32() & 0x1f));
@@ -1693,7 +1658,7 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
             callFrame->r(dst) = result;
         }
 
-        ++vPC;
+        vPC += OPCODE_LENGTH(op_lshift);
         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_rshift) {
@@ -1703,9 +1668,9 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
            to int32) by register shift (converted to
            uint32), and puts the result in register dst.
         */
-        int dst = (++vPC)->u.operand;
-        JSValue val = callFrame->r((++vPC)->u.operand).jsValue();
-        JSValue shift = callFrame->r((++vPC)->u.operand).jsValue();
+        int dst = vPC[1].u.operand;
+        JSValue val = callFrame->r(vPC[2].u.operand).jsValue();
+        JSValue shift = callFrame->r(vPC[3].u.operand).jsValue();
 
         if (val.isInt32() && shift.isInt32())
             callFrame->r(dst) = jsNumber(callFrame, val.asInt32() >> (shift.asInt32() & 0x1f));
@@ -1715,7 +1680,7 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
             callFrame->r(dst) = result;
         }
 
-        ++vPC;
+        vPC += OPCODE_LENGTH(op_rshift);
         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_urshift) {
@@ -1725,9 +1690,9 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
            to uint32) by register shift (converted to
            uint32), and puts the result in register dst.
         */
-        int dst = (++vPC)->u.operand;
-        JSValue val = callFrame->r((++vPC)->u.operand).jsValue();
-        JSValue shift = callFrame->r((++vPC)->u.operand).jsValue();
+        int dst = vPC[1].u.operand;
+        JSValue val = callFrame->r(vPC[2].u.operand).jsValue();
+        JSValue shift = callFrame->r(vPC[3].u.operand).jsValue();
         if (val.isUInt32() && shift.isInt32())
             callFrame->r(dst) = jsNumber(callFrame, val.asInt32() >> (shift.asInt32() & 0x1f));
         else {
@@ -1736,7 +1701,7 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
             callFrame->r(dst) = result;
         }
 
-        ++vPC;
+        vPC += OPCODE_LENGTH(op_urshift);
         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_bitand) {
@@ -1746,9 +1711,9 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
            and register src2 (converted to int32), and puts the result
            in register dst.
         */
-        int dst = (++vPC)->u.operand;
-        JSValue src1 = callFrame->r((++vPC)->u.operand).jsValue();
-        JSValue src2 = callFrame->r((++vPC)->u.operand).jsValue();
+        int dst = vPC[1].u.operand;
+        JSValue src1 = callFrame->r(vPC[2].u.operand).jsValue();
+        JSValue src2 = callFrame->r(vPC[3].u.operand).jsValue();
         if (src1.isInt32() && src2.isInt32())
             callFrame->r(dst) = jsNumber(callFrame, src1.asInt32() & src2.asInt32());
         else {
@@ -1757,7 +1722,7 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
             callFrame->r(dst) = result;
         }
 
-        vPC += 2;
+        vPC += OPCODE_LENGTH(op_bitand);
         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_bitxor) {
@@ -1767,9 +1732,9 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
            and register src2 (converted to int32), and puts the result
            in register dst.
         */
-        int dst = (++vPC)->u.operand;
-        JSValue src1 = callFrame->r((++vPC)->u.operand).jsValue();
-        JSValue src2 = callFrame->r((++vPC)->u.operand).jsValue();
+        int dst = vPC[1].u.operand;
+        JSValue src1 = callFrame->r(vPC[2].u.operand).jsValue();
+        JSValue src2 = callFrame->r(vPC[3].u.operand).jsValue();
         if (src1.isInt32() && src2.isInt32())
             callFrame->r(dst) = jsNumber(callFrame, src1.asInt32() ^ src2.asInt32());
         else {
@@ -1778,7 +1743,7 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
             callFrame->r(dst) = result;
         }
 
-        vPC += 2;
+        vPC += OPCODE_LENGTH(op_bitxor);
         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_bitor) {
@@ -1788,9 +1753,9 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
            and register src2 (converted to int32), and puts the
            result in register dst.
         */
-        int dst = (++vPC)->u.operand;
-        JSValue src1 = callFrame->r((++vPC)->u.operand).jsValue();
-        JSValue src2 = callFrame->r((++vPC)->u.operand).jsValue();
+        int dst = vPC[1].u.operand;
+        JSValue src1 = callFrame->r(vPC[2].u.operand).jsValue();
+        JSValue src2 = callFrame->r(vPC[3].u.operand).jsValue();
         if (src1.isInt32() && src2.isInt32())
             callFrame->r(dst) = jsNumber(callFrame, src1.asInt32() | src2.asInt32());
         else {
@@ -1799,7 +1764,7 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
             callFrame->r(dst) = result;
         }
 
-        vPC += 2;
+        vPC += OPCODE_LENGTH(op_bitor);
         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_bitnot) {
@@ -1808,8 +1773,8 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
            Computes bitwise NOT of register src1 (converted to int32),
            and puts the result in register dst.
         */
-        int dst = (++vPC)->u.operand;
-        JSValue src = callFrame->r((++vPC)->u.operand).jsValue();
+        int dst = vPC[1].u.operand;
+        JSValue src = callFrame->r(vPC[2].u.operand).jsValue();
         if (src.isInt32())
             callFrame->r(dst) = jsNumber(callFrame, ~src.asInt32());
         else {
@@ -1817,7 +1782,7 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
             CHECK_FOR_EXCEPTION();
             callFrame->r(dst) = result;
         }
-        ++vPC;
+        vPC += OPCODE_LENGTH(op_bitnot);
         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_not) {
@@ -1826,13 +1791,13 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
            Computes logical NOT of register src (converted to
            boolean), and puts the result in register dst.
         */
-        int dst = (++vPC)->u.operand;
-        int src = (++vPC)->u.operand;
+        int dst = vPC[1].u.operand;
+        int src = vPC[2].u.operand;
         JSValue result = jsBoolean(!callFrame->r(src).jsValue().toBoolean(callFrame));
         CHECK_FOR_EXCEPTION();
         callFrame->r(dst) = result;
 
-        ++vPC;
+        vPC += OPCODE_LENGTH(op_not);
         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_instanceof) {
@@ -1862,7 +1827,7 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
         CHECK_FOR_EXCEPTION();
         callFrame->r(dst) = jsBoolean(result);
 
-        vPC += 5;
+        vPC += OPCODE_LENGTH(op_instanceof);
         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_typeof) {
@@ -1871,11 +1836,11 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
            Determines the type string for src according to ECMAScript
            rules, and puts the result in register dst.
         */
-        int dst = (++vPC)->u.operand;
-        int src = (++vPC)->u.operand;
+        int dst = vPC[1].u.operand;
+        int src = vPC[2].u.operand;
         callFrame->r(dst) = JSValue(jsTypeStringForValue(callFrame, callFrame->r(src).jsValue()));
 
-        ++vPC;
+        vPC += OPCODE_LENGTH(op_typeof);
         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_is_undefined) {
@@ -1885,12 +1850,12 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
            the ECMAScript rules is "undefined", and puts the result
            in register dst.
         */
-        int dst = (++vPC)->u.operand;
-        int src = (++vPC)->u.operand;
+        int dst = vPC[1].u.operand;
+        int src = vPC[2].u.operand;
         JSValue v = callFrame->r(src).jsValue();
         callFrame->r(dst) = jsBoolean(v.isCell() ? v.asCell()->structure()->typeInfo().masqueradesAsUndefined() : v.isUndefined());
 
-        ++vPC;
+        vPC += OPCODE_LENGTH(op_is_undefined);
         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_is_boolean) {
@@ -1900,11 +1865,11 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
            the ECMAScript rules is "boolean", and puts the result
            in register dst.
         */
-        int dst = (++vPC)->u.operand;
-        int src = (++vPC)->u.operand;
+        int dst = vPC[1].u.operand;
+        int src = vPC[2].u.operand;
         callFrame->r(dst) = jsBoolean(callFrame->r(src).jsValue().isBoolean());
 
-        ++vPC;
+        vPC += OPCODE_LENGTH(op_is_boolean);
         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_is_number) {
@@ -1914,11 +1879,11 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
            the ECMAScript rules is "number", and puts the result
            in register dst.
         */
-        int dst = (++vPC)->u.operand;
-        int src = (++vPC)->u.operand;
+        int dst = vPC[1].u.operand;
+        int src = vPC[2].u.operand;
         callFrame->r(dst) = jsBoolean(callFrame->r(src).jsValue().isNumber());
 
-        ++vPC;
+        vPC += OPCODE_LENGTH(op_is_number);
         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_is_string) {
@@ -1928,11 +1893,11 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
            the ECMAScript rules is "string", and puts the result
            in register dst.
         */
-        int dst = (++vPC)->u.operand;
-        int src = (++vPC)->u.operand;
+        int dst = vPC[1].u.operand;
+        int src = vPC[2].u.operand;
         callFrame->r(dst) = jsBoolean(callFrame->r(src).jsValue().isString());
 
-        ++vPC;
+        vPC += OPCODE_LENGTH(op_is_string);
         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_is_object) {
@@ -1942,11 +1907,11 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
            the ECMAScript rules is "object", and puts the result
            in register dst.
         */
-        int dst = (++vPC)->u.operand;
-        int src = (++vPC)->u.operand;
+        int dst = vPC[1].u.operand;
+        int src = vPC[2].u.operand;
         callFrame->r(dst) = jsBoolean(jsIsObjectType(callFrame->r(src).jsValue()));
 
-        ++vPC;
+        vPC += OPCODE_LENGTH(op_is_object);
         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_is_function) {
@@ -1956,11 +1921,11 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
            the ECMAScript rules is "function", and puts the result
            in register dst.
         */
-        int dst = (++vPC)->u.operand;
-        int src = (++vPC)->u.operand;
+        int dst = vPC[1].u.operand;
+        int src = vPC[2].u.operand;
         callFrame->r(dst) = jsBoolean(jsIsFunctionType(callFrame->r(src).jsValue()));
 
-        ++vPC;
+        vPC += OPCODE_LENGTH(op_is_function);
         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_in) {
@@ -1972,9 +1937,9 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
            Raises an exception if register constructor is not an
            object.
         */
-        int dst = (++vPC)->u.operand;
-        int property = (++vPC)->u.operand;
-        int base = (++vPC)->u.operand;
+        int dst = vPC[1].u.operand;
+        int property = vPC[2].u.operand;
+        int base = vPC[3].u.operand;
 
         JSValue baseVal = callFrame->r(base).jsValue();
         if (isInvalidParamForIn(callFrame, callFrame->codeBlock(), vPC, baseVal, exceptionValue))
@@ -1993,7 +1958,7 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
             callFrame->r(dst) = jsBoolean(baseObj->hasProperty(callFrame, property));
         }
 
-        ++vPC;
+        vPC += OPCODE_LENGTH(op_in);
         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_resolve) {
@@ -2006,7 +1971,7 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
         if (UNLIKELY(!resolve(callFrame, vPC, exceptionValue)))
             goto vm_throw;
 
-        vPC += 3;
+        vPC += OPCODE_LENGTH(op_resolve);
         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_resolve_skip) {
@@ -2019,7 +1984,7 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
         if (UNLIKELY(!resolveSkip(callFrame, vPC, exceptionValue)))
             goto vm_throw;
 
-        vPC += 4;
+        vPC += OPCODE_LENGTH(op_resolve_skip);
 
         NEXT_INSTRUCTION();
     }
@@ -2034,7 +1999,7 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
         if (UNLIKELY(!resolveGlobal(callFrame, vPC, exceptionValue)))
             goto vm_throw;
         
-        vPC += 6;
+        vPC += OPCODE_LENGTH(op_resolve_global);
         
         NEXT_INSTRUCTION();
     }
@@ -2043,13 +2008,13 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
 
            Gets the global var at global slot index and places it in register dst.
          */
-        int dst = (++vPC)->u.operand;
-        JSGlobalObject* scope = static_cast<JSGlobalObject*>((++vPC)->u.jsCell);
+        int dst = vPC[1].u.operand;
+        JSGlobalObject* scope = static_cast<JSGlobalObject*>(vPC[2].u.jsCell);
         ASSERT(scope->isGlobalObject());
-        int index = (++vPC)->u.operand;
+        int index = vPC[3].u.operand;
 
         callFrame->r(dst) = scope->registerAt(index);
-        ++vPC;
+        vPC += OPCODE_LENGTH(op_get_global_var);
         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_put_global_var) {
@@ -2057,13 +2022,13 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
          
            Puts value into global slot index.
          */
-        JSGlobalObject* scope = static_cast<JSGlobalObject*>((++vPC)->u.jsCell);
+        JSGlobalObject* scope = static_cast<JSGlobalObject*>(vPC[1].u.jsCell);
         ASSERT(scope->isGlobalObject());
-        int index = (++vPC)->u.operand;
-        int value = (++vPC)->u.operand;
+        int index = vPC[2].u.operand;
+        int value = vPC[3].u.operand;
         
         scope->registerAt(index) = JSValue(callFrame->r(value).jsValue());
-        ++vPC;
+        vPC += OPCODE_LENGTH(op_put_global_var);
         NEXT_INSTRUCTION();
     }            
     DEFINE_OPCODE(op_get_scoped_var) {
@@ -2072,9 +2037,9 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
          Loads the contents of the index-th local from the scope skip nodes from
          the top of the scope chain, and places it in register dst
          */
-        int dst = (++vPC)->u.operand;
-        int index = (++vPC)->u.operand;
-        int skip = (++vPC)->u.operand + callFrame->codeBlock()->needsFullScopeChain();
+        int dst = vPC[1].u.operand;
+        int index = vPC[2].u.operand;
+        int skip = vPC[3].u.operand + callFrame->codeBlock()->needsFullScopeChain();
 
         ScopeChainNode* scopeChain = callFrame->scopeChain();
         ScopeChainIterator iter = scopeChain->begin();
@@ -2088,16 +2053,16 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
         ASSERT((*iter)->isVariableObject());
         JSVariableObject* scope = static_cast<JSVariableObject*>(*iter);
         callFrame->r(dst) = scope->registerAt(index);
-        ++vPC;
+        vPC += OPCODE_LENGTH(op_get_scoped_var);
         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_put_scoped_var) {
         /* put_scoped_var index(n) skip(n) value(r)
 
          */
-        int index = (++vPC)->u.operand;
-        int skip = (++vPC)->u.operand + callFrame->codeBlock()->needsFullScopeChain();
-        int value = (++vPC)->u.operand;
+        int index = vPC[1].u.operand;
+        int skip = vPC[2].u.operand + callFrame->codeBlock()->needsFullScopeChain();
+        int value = vPC[3].u.operand;
 
         ScopeChainNode* scopeChain = callFrame->scopeChain();
         ScopeChainIterator iter = scopeChain->begin();
@@ -2111,7 +2076,7 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
         ASSERT((*iter)->isVariableObject());
         JSVariableObject* scope = static_cast<JSVariableObject*>(*iter);
         scope->registerAt(index) = JSValue(callFrame->r(value).jsValue());
-        ++vPC;
+        vPC += OPCODE_LENGTH(op_put_scoped_var);
         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_resolve_base) {
@@ -2124,7 +2089,7 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
         */
         resolveBase(callFrame, vPC);
 
-        vPC += 3;
+        vPC += OPCODE_LENGTH(op_resolve_base);
         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_resolve_with_base) {
@@ -2142,7 +2107,7 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
         if (UNLIKELY(!resolveBaseAndProperty(callFrame, vPC, exceptionValue)))
             goto vm_throw;
 
-        vPC += 4;
+        vPC += OPCODE_LENGTH(op_resolve_with_base);
         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_get_by_id) {
@@ -2165,7 +2130,7 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
         tryCacheGetByID(callFrame, codeBlock, vPC, baseValue, ident, slot);
 
         callFrame->r(dst) = result;
-        vPC += 8;
+        vPC += OPCODE_LENGTH(op_get_by_id);
         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_get_by_id_self) {
@@ -2191,7 +2156,7 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
                 ASSERT(baseObject->get(callFrame, callFrame->codeBlock()->identifier(vPC[3].u.operand)) == baseObject->getDirectOffset(offset));
                 callFrame->r(dst) = JSValue(baseObject->getDirectOffset(offset));
 
-                vPC += 8;
+                vPC += OPCODE_LENGTH(op_get_by_id_self);
                 NEXT_INSTRUCTION();
             }
         }
@@ -2223,9 +2188,10 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
                     int offset = vPC[6].u.operand;
 
                     ASSERT(protoObject->get(callFrame, callFrame->codeBlock()->identifier(vPC[3].u.operand)) == protoObject->getDirectOffset(offset));
+                    ASSERT(baseValue.get(callFrame, callFrame->codeBlock()->identifier(vPC[3].u.operand)) == protoObject->getDirectOffset(offset));
                     callFrame->r(dst) = JSValue(protoObject->getDirectOffset(offset));
 
-                    vPC += 8;
+                    vPC += OPCODE_LENGTH(op_get_by_id_proto);
                     NEXT_INSTRUCTION();
                 }
             }
@@ -2238,14 +2204,14 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
         // Polymorphic self access caching currently only supported when JITting.
         ASSERT_NOT_REACHED();
         // This case of the switch must not be empty, else (op_get_by_id_self_list == op_get_by_id_chain)!
-        vPC += 8;
+        vPC += OPCODE_LENGTH(op_get_by_id_self_list);
         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_get_by_id_proto_list) {
         // Polymorphic prototype access caching currently only supported when JITting.
         ASSERT_NOT_REACHED();
         // This case of the switch must not be empty, else (op_get_by_id_proto_list == op_get_by_id_chain)!
-        vPC += 8;
+        vPC += OPCODE_LENGTH(op_get_by_id_proto_list);
         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_get_by_id_chain) {
@@ -2278,9 +2244,10 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
                         int offset = vPC[7].u.operand;
 
                         ASSERT(baseObject->get(callFrame, callFrame->codeBlock()->identifier(vPC[3].u.operand)) == baseObject->getDirectOffset(offset));
+                        ASSERT(baseValue.get(callFrame, callFrame->codeBlock()->identifier(vPC[3].u.operand)) == baseObject->getDirectOffset(offset));
                         callFrame->r(dst) = JSValue(baseObject->getDirectOffset(offset));
 
-                        vPC += 8;
+                        vPC += OPCODE_LENGTH(op_get_by_id_chain);
                         NEXT_INSTRUCTION();
                     }
 
@@ -2310,7 +2277,7 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
         CHECK_FOR_EXCEPTION();
 
         callFrame->r(dst) = result;
-        vPC += 8;
+        vPC += OPCODE_LENGTH(op_get_by_id_generic);
         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_get_array_length) {
@@ -2326,7 +2293,7 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
         if (LIKELY(isJSArray(globalData, baseValue))) {
             int dst = vPC[1].u.operand;
             callFrame->r(dst) = jsNumber(callFrame, asArray(baseValue)->length());
-            vPC += 8;
+            vPC += OPCODE_LENGTH(op_get_array_length);
             NEXT_INSTRUCTION();
         }
 
@@ -2345,8 +2312,8 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
         JSValue baseValue = callFrame->r(base).jsValue();
         if (LIKELY(isJSString(globalData, baseValue))) {
             int dst = vPC[1].u.operand;
-            callFrame->r(dst) = jsNumber(callFrame, asString(baseValue)->value().size());
-            vPC += 8;
+            callFrame->r(dst) = jsNumber(callFrame, asString(baseValue)->length());
+            vPC += OPCODE_LENGTH(op_get_string_length);
             NEXT_INSTRUCTION();
         }
 
@@ -2376,7 +2343,7 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
 
         tryCachePutByID(callFrame, codeBlock, vPC, baseValue, slot);
 
-        vPC += 8;
+        vPC += OPCODE_LENGTH(op_put_by_id);
         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_put_by_id_transition) {
@@ -2421,7 +2388,7 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
                 ASSERT(baseObject->offsetForLocation(baseObject->getDirectLocation(callFrame->codeBlock()->identifier(vPC[2].u.operand))) == offset);
                 baseObject->putDirectOffset(offset, callFrame->r(value).jsValue());
 
-                vPC += 8;
+                vPC += OPCODE_LENGTH(op_put_by_id_transition);
                 NEXT_INSTRUCTION();
             }
         }
@@ -2456,7 +2423,7 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
                 ASSERT(baseObject->offsetForLocation(baseObject->getDirectLocation(callFrame->codeBlock()->identifier(vPC[2].u.operand))) == offset);
                 baseObject->putDirectOffset(offset, callFrame->r(value).jsValue());
 
-                vPC += 8;
+                vPC += OPCODE_LENGTH(op_put_by_id_replace);
                 NEXT_INSTRUCTION();
             }
         }
@@ -2483,7 +2450,7 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
         baseValue.put(callFrame, ident, callFrame->r(value).jsValue(), slot);
         CHECK_FOR_EXCEPTION();
 
-        vPC += 8;
+        vPC += OPCODE_LENGTH(op_put_by_id_generic);
         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_del_by_id) {
@@ -2494,16 +2461,43 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
            boolean indicating success (if true) or failure (if false)
            to register dst.
         */
-        int dst = (++vPC)->u.operand;
-        int base = (++vPC)->u.operand;
-        int property = (++vPC)->u.operand;
+        int dst = vPC[1].u.operand;
+        int base = vPC[2].u.operand;
+        int property = vPC[3].u.operand;
 
         JSObject* baseObj = callFrame->r(base).jsValue().toObject(callFrame);
         Identifier& ident = callFrame->codeBlock()->identifier(property);
         JSValue result = jsBoolean(baseObj->deleteProperty(callFrame, ident));
         CHECK_FOR_EXCEPTION();
         callFrame->r(dst) = result;
-        ++vPC;
+        vPC += OPCODE_LENGTH(op_del_by_id);
+        NEXT_INSTRUCTION();
+    }
+    DEFINE_OPCODE(op_get_by_pname) {
+        int dst = vPC[1].u.operand;
+        int base = vPC[2].u.operand;
+        int property = vPC[3].u.operand;
+        int expected = vPC[4].u.operand;
+        int iter = vPC[5].u.operand;
+        int i = vPC[6].u.operand;
+
+        JSValue baseValue = callFrame->r(base).jsValue();
+        JSPropertyNameIterator* it = callFrame->r(iter).propertyNameIterator();
+        JSValue subscript = callFrame->r(property).jsValue();
+        JSValue expectedSubscript = callFrame->r(expected).jsValue();
+        int index = callFrame->r(i).i() - 1;
+        JSValue result;
+        int offset = 0;
+        if (subscript == expectedSubscript && baseValue.isCell() && (baseValue.asCell()->structure() == it->cachedStructure()) && it->getOffset(index, offset)) {
+            callFrame->r(dst) = asObject(baseValue)->getDirectOffset(offset);
+            vPC += OPCODE_LENGTH(op_get_by_pname);
+            NEXT_INSTRUCTION();
+        }
+        Identifier propertyName(callFrame, subscript.toString(callFrame));
+        result = baseValue.get(callFrame, propertyName);
+        CHECK_FOR_EXCEPTION();
+        callFrame->r(dst) = result;
+        vPC += OPCODE_LENGTH(op_get_by_pname);
         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_get_by_val) {
@@ -2514,9 +2508,9 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
            in register dst. property is nominally converted to string
            but numbers are treated more efficiently.
         */
-        int dst = (++vPC)->u.operand;
-        int base = (++vPC)->u.operand;
-        int property = (++vPC)->u.operand;
+        int dst = vPC[1].u.operand;
+        int base = vPC[2].u.operand;
+        int property = vPC[3].u.operand;
         
         JSValue baseValue = callFrame->r(base).jsValue();
         JSValue subscript = callFrame->r(property).jsValue();
@@ -2532,7 +2526,7 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
                 else
                     result = jsArray->JSArray::get(callFrame, i);
             } else if (isJSString(globalData, baseValue) && asString(baseValue)->canGetIndex(i))
-                result = asString(baseValue)->getIndex(&callFrame->globalData(), i);
+                result = asString(baseValue)->getIndex(callFrame, i);
             else if (isJSByteArray(globalData, baseValue) && asByteArray(baseValue)->canAccessIndex(i))
                 result = asByteArray(baseValue)->getIndex(callFrame, i);
             else
@@ -2544,7 +2538,7 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
 
         CHECK_FOR_EXCEPTION();
         callFrame->r(dst) = result;
-        ++vPC;
+        vPC += OPCODE_LENGTH(op_get_by_val);
         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_put_by_val) {
@@ -2558,9 +2552,9 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
            Unlike many opcodes, this one does not write any output to
            the register file.
         */
-        int base = (++vPC)->u.operand;
-        int property = (++vPC)->u.operand;
-        int value = (++vPC)->u.operand;
+        int base = vPC[1].u.operand;
+        int property = vPC[2].u.operand;
+        int value = vPC[3].u.operand;
 
         JSValue baseValue = callFrame->r(base).jsValue();
         JSValue subscript = callFrame->r(property).jsValue();
@@ -2594,7 +2588,7 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
         }
 
         CHECK_FOR_EXCEPTION();
-        ++vPC;
+        vPC += OPCODE_LENGTH(op_put_by_val);
         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_del_by_val) {
@@ -2605,9 +2599,9 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
            boolean indicating success (if true) or failure (if false)
            to register dst.
         */
-        int dst = (++vPC)->u.operand;
-        int base = (++vPC)->u.operand;
-        int property = (++vPC)->u.operand;
+        int dst = vPC[1].u.operand;
+        int base = vPC[2].u.operand;
+        int property = vPC[3].u.operand;
 
         JSObject* baseObj = callFrame->r(base).jsValue().toObject(callFrame); // may throw
 
@@ -2625,7 +2619,7 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
 
         CHECK_FOR_EXCEPTION();
         callFrame->r(dst) = result;
-        ++vPC;
+        vPC += OPCODE_LENGTH(op_del_by_val);
         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_put_by_index) {
@@ -2640,13 +2634,13 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
 
            This opcode is mainly used to initialize array literals.
         */
-        int base = (++vPC)->u.operand;
-        unsigned property = (++vPC)->u.operand;
-        int value = (++vPC)->u.operand;
+        int base = vPC[1].u.operand;
+        unsigned property = vPC[2].u.operand;
+        int value = vPC[3].u.operand;
 
         callFrame->r(base).jsValue().put(callFrame, property, callFrame->r(value).jsValue());
 
-        ++vPC;
+        vPC += OPCODE_LENGTH(op_put_by_index);
         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_loop) {
@@ -2661,7 +2655,7 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
 #if ENABLE(OPCODE_STATS)
         OpcodeStats::resetLastInstruction();
 #endif
-        int target = (++vPC)->u.operand;
+        int target = vPC[1].u.operand;
         CHECK_FOR_TIMEOUT();
         vPC += target;
         NEXT_INSTRUCTION();
@@ -2675,7 +2669,7 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
 #if ENABLE(OPCODE_STATS)
         OpcodeStats::resetLastInstruction();
 #endif
-        int target = (++vPC)->u.operand;
+        int target = vPC[1].u.operand;
 
         vPC += target;
         NEXT_INSTRUCTION();
@@ -2689,15 +2683,35 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
            Additionally this loop instruction may terminate JS execution is
            the JS timeout is reached.
          */
-        int cond = (++vPC)->u.operand;
-        int target = (++vPC)->u.operand;
+        int cond = vPC[1].u.operand;
+        int target = vPC[2].u.operand;
         if (callFrame->r(cond).jsValue().toBoolean(callFrame)) {
             vPC += target;
             CHECK_FOR_TIMEOUT();
             NEXT_INSTRUCTION();
         }
         
-        ++vPC;
+        vPC += OPCODE_LENGTH(op_loop_if_true);
+        NEXT_INSTRUCTION();
+    }
+    DEFINE_OPCODE(op_loop_if_false) {
+        /* loop_if_true cond(r) target(offset)
+         
+           Jumps to offset target from the current instruction, if and
+           only if register cond converts to boolean as false.
+
+           Additionally this loop instruction may terminate JS execution is
+           the JS timeout is reached.
+         */
+        int cond = vPC[1].u.operand;
+        int target = vPC[2].u.operand;
+        if (!callFrame->r(cond).jsValue().toBoolean(callFrame)) {
+            vPC += target;
+            CHECK_FOR_TIMEOUT();
+            NEXT_INSTRUCTION();
+        }
+        
+        vPC += OPCODE_LENGTH(op_loop_if_true);
         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_jtrue) {
@@ -2706,14 +2720,14 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
            Jumps to offset target from the current instruction, if and
            only if register cond converts to boolean as true.
         */
-        int cond = (++vPC)->u.operand;
-        int target = (++vPC)->u.operand;
+        int cond = vPC[1].u.operand;
+        int target = vPC[2].u.operand;
         if (callFrame->r(cond).jsValue().toBoolean(callFrame)) {
             vPC += target;
             NEXT_INSTRUCTION();
         }
 
-        ++vPC;
+        vPC += OPCODE_LENGTH(op_jtrue);
         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_jfalse) {
@@ -2722,14 +2736,14 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
            Jumps to offset target from the current instruction, if and
            only if register cond converts to boolean as false.
         */
-        int cond = (++vPC)->u.operand;
-        int target = (++vPC)->u.operand;
+        int cond = vPC[1].u.operand;
+        int target = vPC[2].u.operand;
         if (!callFrame->r(cond).jsValue().toBoolean(callFrame)) {
             vPC += target;
             NEXT_INSTRUCTION();
         }
 
-        ++vPC;
+        vPC += OPCODE_LENGTH(op_jfalse);
         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_jeq_null) {
@@ -2738,8 +2752,8 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
            Jumps to offset target from the current instruction, if and
            only if register src is null.
         */
-        int src = (++vPC)->u.operand;
-        int target = (++vPC)->u.operand;
+        int src = vPC[1].u.operand;
+        int target = vPC[2].u.operand;
         JSValue srcValue = callFrame->r(src).jsValue();
 
         if (srcValue.isUndefinedOrNull() || (srcValue.isCell() && srcValue.asCell()->structure()->typeInfo().masqueradesAsUndefined())) {
@@ -2747,7 +2761,7 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
             NEXT_INSTRUCTION();
         }
 
-        ++vPC;
+        vPC += OPCODE_LENGTH(op_jeq_null);
         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_jneq_null) {
@@ -2756,16 +2770,16 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
            Jumps to offset target from the current instruction, if and
            only if register src is not null.
         */
-        int src = (++vPC)->u.operand;
-        int target = (++vPC)->u.operand;
+        int src = vPC[1].u.operand;
+        int target = vPC[2].u.operand;
         JSValue srcValue = callFrame->r(src).jsValue();
 
-        if (!srcValue.isUndefinedOrNull() || (srcValue.isCell() && !srcValue.asCell()->structure()->typeInfo().masqueradesAsUndefined())) {
+        if (!srcValue.isUndefinedOrNull() && (!srcValue.isCell() || !srcValue.asCell()->structure()->typeInfo().masqueradesAsUndefined())) {
             vPC += target;
             NEXT_INSTRUCTION();
         }
 
-        ++vPC;
+        vPC += OPCODE_LENGTH(op_jneq_null);
         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_jneq_ptr) {
@@ -2774,16 +2788,16 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
            Jumps to offset target from the current instruction, if the value r is equal
            to ptr, using pointer equality.
          */
-        int src = (++vPC)->u.operand;
-        JSValue ptr = JSValue((++vPC)->u.jsCell);
-        int target = (++vPC)->u.operand;
+        int src = vPC[1].u.operand;
+        JSValue ptr = JSValue(vPC[2].u.jsCell);
+        int target = vPC[3].u.operand;
         JSValue srcValue = callFrame->r(src).jsValue();
         if (srcValue != ptr) {
             vPC += target;
             NEXT_INSTRUCTION();
         }
 
-        ++vPC;
+        vPC += OPCODE_LENGTH(op_jneq_ptr);
         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_loop_if_less) {
@@ -2797,9 +2811,9 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
            Additionally this loop instruction may terminate JS execution is
            the JS timeout is reached.
          */
-        JSValue src1 = callFrame->r((++vPC)->u.operand).jsValue();
-        JSValue src2 = callFrame->r((++vPC)->u.operand).jsValue();
-        int target = (++vPC)->u.operand;
+        JSValue src1 = callFrame->r(vPC[1].u.operand).jsValue();
+        JSValue src2 = callFrame->r(vPC[2].u.operand).jsValue();
+        int target = vPC[3].u.operand;
         
         bool result = jsLess(callFrame, src1, src2);
         CHECK_FOR_EXCEPTION();
@@ -2810,7 +2824,7 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
             NEXT_INSTRUCTION();
         }
         
-        ++vPC;
+        vPC += OPCODE_LENGTH(op_loop_if_less);
         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_loop_if_lesseq) {
@@ -2824,9 +2838,9 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
            Additionally this loop instruction may terminate JS execution is
            the JS timeout is reached.
         */
-        JSValue src1 = callFrame->r((++vPC)->u.operand).jsValue();
-        JSValue src2 = callFrame->r((++vPC)->u.operand).jsValue();
-        int target = (++vPC)->u.operand;
+        JSValue src1 = callFrame->r(vPC[1].u.operand).jsValue();
+        JSValue src2 = callFrame->r(vPC[2].u.operand).jsValue();
+        int target = vPC[3].u.operand;
         
         bool result = jsLessEq(callFrame, src1, src2);
         CHECK_FOR_EXCEPTION();
@@ -2837,7 +2851,7 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
             NEXT_INSTRUCTION();
         }
         
-        ++vPC;
+        vPC += OPCODE_LENGTH(op_loop_if_lesseq);
         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_jnless) {
@@ -2848,9 +2862,9 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
            target from the current instruction, if and only if the 
            result of the comparison is false.
         */
-        JSValue src1 = callFrame->r((++vPC)->u.operand).jsValue();
-        JSValue src2 = callFrame->r((++vPC)->u.operand).jsValue();
-        int target = (++vPC)->u.operand;
+        JSValue src1 = callFrame->r(vPC[1].u.operand).jsValue();
+        JSValue src2 = callFrame->r(vPC[2].u.operand).jsValue();
+        int target = vPC[3].u.operand;
 
         bool result = jsLess(callFrame, src1, src2);
         CHECK_FOR_EXCEPTION();
@@ -2860,7 +2874,30 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
             NEXT_INSTRUCTION();
         }
 
-        ++vPC;
+        vPC += OPCODE_LENGTH(op_jnless);
+        NEXT_INSTRUCTION();
+    }
+    DEFINE_OPCODE(op_jless) {
+        /* jless src1(r) src2(r) target(offset)
+
+           Checks whether register src1 is less than register src2, as
+           with the ECMAScript '<' operator, and then jumps to offset
+           target from the current instruction, if and only if the 
+           result of the comparison is true.
+        */
+        JSValue src1 = callFrame->r(vPC[1].u.operand).jsValue();
+        JSValue src2 = callFrame->r(vPC[2].u.operand).jsValue();
+        int target = vPC[3].u.operand;
+
+        bool result = jsLess(callFrame, src1, src2);
+        CHECK_FOR_EXCEPTION();
+        
+        if (result) {
+            vPC += target;
+            NEXT_INSTRUCTION();
+        }
+
+        vPC += OPCODE_LENGTH(op_jless);
         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_jnlesseq) {
@@ -2871,9 +2908,9 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
            and then jumps to offset target from the current instruction,
            if and only if theresult of the comparison is false.
         */
-        JSValue src1 = callFrame->r((++vPC)->u.operand).jsValue();
-        JSValue src2 = callFrame->r((++vPC)->u.operand).jsValue();
-        int target = (++vPC)->u.operand;
+        JSValue src1 = callFrame->r(vPC[1].u.operand).jsValue();
+        JSValue src2 = callFrame->r(vPC[2].u.operand).jsValue();
+        int target = vPC[3].u.operand;
 
         bool result = jsLessEq(callFrame, src1, src2);
         CHECK_FOR_EXCEPTION();
@@ -2883,7 +2920,7 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
             NEXT_INSTRUCTION();
         }
 
-        ++vPC;
+        vPC += OPCODE_LENGTH(op_jnlesseq);
         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_switch_imm) {
@@ -2895,9 +2932,9 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
            table, and the value at jumpTable[scrutinee value] is non-zero, then
            that value is used as the jump offset, otherwise defaultOffset is used.
          */
-        int tableIndex = (++vPC)->u.operand;
-        int defaultOffset = (++vPC)->u.operand;
-        JSValue scrutinee = callFrame->r((++vPC)->u.operand).jsValue();
+        int tableIndex = vPC[1].u.operand;
+        int defaultOffset = vPC[2].u.operand;
+        JSValue scrutinee = callFrame->r(vPC[3].u.operand).jsValue();
         if (scrutinee.isInt32())
             vPC += callFrame->codeBlock()->immediateSwitchJumpTable(tableIndex).offsetForValue(scrutinee.asInt32(), defaultOffset);
         else {
@@ -2919,13 +2956,13 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
            table, and the value at jumpTable[scrutinee value] is non-zero, then
            that value is used as the jump offset, otherwise defaultOffset is used.
          */
-        int tableIndex = (++vPC)->u.operand;
-        int defaultOffset = (++vPC)->u.operand;
-        JSValue scrutinee = callFrame->r((++vPC)->u.operand).jsValue();
+        int tableIndex = vPC[1].u.operand;
+        int defaultOffset = vPC[2].u.operand;
+        JSValue scrutinee = callFrame->r(vPC[3].u.operand).jsValue();
         if (!scrutinee.isString())
             vPC += defaultOffset;
         else {
-            UString::Rep* value = asString(scrutinee)->value().rep();
+            UString::Rep* value = asString(scrutinee)->value(callFrame).rep();
             if (value->size() != 1)
                 vPC += defaultOffset;
             else
@@ -2942,13 +2979,13 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
            jump table, then the value associated with the string is used as the 
            jump offset, otherwise defaultOffset is used.
          */
-        int tableIndex = (++vPC)->u.operand;
-        int defaultOffset = (++vPC)->u.operand;
-        JSValue scrutinee = callFrame->r((++vPC)->u.operand).jsValue();
+        int tableIndex = vPC[1].u.operand;
+        int defaultOffset = vPC[2].u.operand;
+        JSValue scrutinee = callFrame->r(vPC[3].u.operand).jsValue();
         if (!scrutinee.isString())
             vPC += defaultOffset;
         else 
-            vPC += callFrame->codeBlock()->stringSwitchJumpTable(tableIndex).offsetForValue(asString(scrutinee)->value().rep(), defaultOffset);
+            vPC += callFrame->codeBlock()->stringSwitchJumpTable(tableIndex).offsetForValue(asString(scrutinee)->value(callFrame).rep(), defaultOffset);
         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_new_func) {
@@ -2959,12 +2996,12 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
            constructor, using the rules for function declarations, and
            puts the result in register dst.
         */
-        int dst = (++vPC)->u.operand;
-        int func = (++vPC)->u.operand;
+        int dst = vPC[1].u.operand;
+        int func = vPC[2].u.operand;
 
         callFrame->r(dst) = JSValue(callFrame->codeBlock()->functionDecl(func)->make(callFrame, callFrame->scopeChain()));
 
-        ++vPC;
+        vPC += OPCODE_LENGTH(op_new_func);
         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_new_func_exp) {
@@ -2975,8 +3012,8 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
            constructor, using the rules for function expressions, and
            puts the result in register dst.
         */
-        int dst = (++vPC)->u.operand;
-        int funcIndex = (++vPC)->u.operand;
+        int dst = vPC[1].u.operand;
+        int funcIndex = vPC[2].u.operand;
 
         FunctionExecutable* function = callFrame->codeBlock()->functionExpr(funcIndex);
         JSFunction* func = function->make(callFrame, callFrame->scopeChain());
@@ -2995,7 +3032,7 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
 
         callFrame->r(dst) = JSValue(func);
 
-        ++vPC;
+        vPC += OPCODE_LENGTH(op_new_func_exp);
         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_call_eval) {
@@ -3020,7 +3057,7 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
         Register* newCallFrame = callFrame->registers() + registerOffset;
         Register* argv = newCallFrame - RegisterFile::CallFrameHeaderSize - argCount;
         JSValue thisValue = argv[0].jsValue();
-        JSGlobalObject* globalObject = callFrame->scopeChain()->globalObject();
+        JSGlobalObject* globalObject = callFrame->scopeChain()->globalObject;
 
         if (thisValue == globalObject && funcVal == globalObject->evalFunction()) {
             JSValue result = callEval(callFrame, registerFile, argv, argCount, registerOffset, exceptionValue);
@@ -3028,7 +3065,7 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
                 goto vm_throw;
             callFrame->r(dst) = result;
 
-            vPC += 5;
+            vPC += OPCODE_LENGTH(op_call_eval);
             NEXT_INSTRUCTION();
         }
 
@@ -3088,7 +3125,6 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
 #else
             newCallFrame->init(0, vPC + 5, scopeChain, callFrame, dst, argCount, asObject(v));
 #endif
-
             Register* thisRegister = newCallFrame->registers() - RegisterFile::CallFrameHeaderSize - argCount;
             ArgList args(thisRegister + 1, argCount - 1);
 
@@ -3099,14 +3135,14 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
 
             JSValue returnValue;
             {
-                SamplingTool::HostCallRecord callRecord(m_sampler);
+                SamplingTool::HostCallRecord callRecord(m_sampler.get());
                 returnValue = callData.native.function(newCallFrame, asObject(v), thisValue, args);
             }
             CHECK_FOR_EXCEPTION();
 
             callFrame->r(dst) = returnValue;
 
-            vPC += 5;
+            vPC += OPCODE_LENGTH(op_call);
             NEXT_INSTRUCTION();
         }
 
@@ -3116,8 +3152,8 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
         goto vm_throw;
     }
     DEFINE_OPCODE(op_load_varargs) {
-        int argCountDst = (++vPC)->u.operand;
-        int argsOffset = (++vPC)->u.operand;
+        int argCountDst = vPC[1].u.operand;
+        int argsOffset = vPC[2].u.operand;
         
         JSValue arguments = callFrame->r(argsOffset).jsValue();
         int32_t argCount = 0;
@@ -3189,7 +3225,7 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
         }
         CHECK_FOR_EXCEPTION();
         callFrame->r(argCountDst) = Register::withInt(argCount + 1);
-        ++vPC;
+        vPC += OPCODE_LENGTH(op_load_varargs);
         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_call_varargs) {
@@ -3246,7 +3282,7 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
 #else
             newCallFrame->init(0, vPC + 5, scopeChain, callFrame, dst, argCount, asObject(v));
 #endif
-
+            
             Register* thisRegister = newCallFrame->registers() - RegisterFile::CallFrameHeaderSize - argCount;
             ArgList args(thisRegister + 1, argCount - 1);
             
@@ -3257,14 +3293,14 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
             
             JSValue returnValue;
             {
-                SamplingTool::HostCallRecord callRecord(m_sampler);
+                SamplingTool::HostCallRecord callRecord(m_sampler.get());
                 returnValue = callData.native.function(newCallFrame, asObject(v), thisValue, args);
             }
             CHECK_FOR_EXCEPTION();
             
             callFrame->r(dst) = returnValue;
             
-            vPC += 5;
+            vPC += OPCODE_LENGTH(op_call_varargs);
             NEXT_INSTRUCTION();
         }
         
@@ -3286,12 +3322,12 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
            This opcode should only be used immediately before op_ret.
         */
 
-        int src = (++vPC)->u.operand;
+        int src = vPC[1].u.operand;
         ASSERT(callFrame->codeBlock()->needsFullScopeChain());
 
         asActivation(callFrame->r(src).jsValue())->copyRegisters(callFrame->optionalCalleeArguments());
 
-        ++vPC;
+        vPC += OPCODE_LENGTH(op_tear_off_activation);
         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_tear_off_arguments) {
@@ -3312,7 +3348,7 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
         if (callFrame->optionalCalleeArguments())
             callFrame->optionalCalleeArguments()->copyRegisters();
 
-        ++vPC;
+        vPC += OPCODE_LENGTH(op_tear_off_arguments);
         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_ret) {
@@ -3330,22 +3366,21 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
         intptr_t sourceId = callFrame->codeBlock()->source()->asID();
 #endif
 
-        int result = (++vPC)->u.operand;
+        int result = vPC[1].u.operand;
 
         if (callFrame->codeBlock()->needsFullScopeChain())
             callFrame->scopeChain()->deref();
 
         JSValue returnValue = callFrame->r(result).jsValue();
 #ifdef QT_BUILD_SCRIPT_LIB
-        if (debugger) {
+        if (debugger)
             debugger->functionExit(returnValue, sourceId);
-        }
 #endif
 
         vPC = callFrame->returnPC();
         int dst = callFrame->returnValueRegister();
         callFrame = callFrame->callerFrame();
-
+        
         if (callFrame->hasHostCallFrameFlag())
             return returnValue;
 
@@ -3370,7 +3405,7 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
         for (size_t count = codeBlock->m_numVars; i < count; ++i)
             callFrame->r(i) = jsUndefined();
 
-        ++vPC;
+        vPC += OPCODE_LENGTH(op_enter);
         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_enter_with_activation) {
@@ -3392,12 +3427,12 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
         for (size_t count = codeBlock->m_numVars; i < count; ++i)
             callFrame->r(i) = jsUndefined();
 
-        int dst = (++vPC)->u.operand;
+        int dst = vPC[1].u.operand;
         JSActivation* activation = new (globalData) JSActivation(callFrame, static_cast<FunctionExecutable*>(codeBlock->ownerExecutable()));
         callFrame->r(dst) = JSValue(activation);
         callFrame->setScopeChain(callFrame->scopeChain()->copy()->push(activation));
 
-        ++vPC;
+        vPC += OPCODE_LENGTH(op_enter_with_activation);
         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_convert_this) {
@@ -3412,12 +3447,12 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
            block.
         */
 
-        int thisRegister = (++vPC)->u.operand;
+        int thisRegister = vPC[1].u.operand;
         JSValue thisVal = callFrame->r(thisRegister).jsValue();
         if (thisVal.needsThisConversion())
             callFrame->r(thisRegister) = JSValue(thisVal.toThisObject(callFrame));
 
-        ++vPC;
+        vPC += OPCODE_LENGTH(op_convert_this);
         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_init_arguments) {
@@ -3431,7 +3466,7 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
            block.
          */
         callFrame->r(RegisterFile::ArgumentsRegister) = JSValue();
-        ++vPC;
+        vPC += OPCODE_LENGTH(op_init_arguments);
         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_create_arguments) {
@@ -3447,7 +3482,7 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
              callFrame->setCalleeArguments(arguments);
              callFrame->r(RegisterFile::ArgumentsRegister) = JSValue(arguments);
          }
-        ++vPC;
+        vPC += OPCODE_LENGTH(op_create_arguments);
         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_construct) {
@@ -3486,11 +3521,10 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
             if (prototype.isObject())
                 structure = asObject(prototype)->inheritorID();
             else
-                structure = callDataScopeChain->globalObject()->emptyObjectStructure();
+                structure = callDataScopeChain->globalObject->emptyObjectStructure();
 #ifdef QT_BUILD_SCRIPT_LIB
             // ### world-class hack
-            QT_PREPEND_NAMESPACE(QScriptObject)* newObject
-                = new (globalData) QT_PREPEND_NAMESPACE(QScriptObject)(structure);
+            QT_PREPEND_NAMESPACE(QScriptObject)* newObject = new (globalData) QT_PREPEND_NAMESPACE(QScriptObject)(structure);
 #else
             JSObject* newObject = new (globalData) JSObject(structure);
 #endif
@@ -3519,7 +3553,6 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
             ArgList args(callFrame->registers() + thisRegister + 1, argCount - 1);
 
             ScopeChainNode* scopeChain = callFrame->scopeChain();
-
             CallFrame* newCallFrame = CallFrame::create(callFrame->registers() + registerOffset);
 #ifdef QT_BUILD_SCRIPT_LIB //we need the returnValue to be 0 as it is used as flags
             newCallFrame->init(0, vPC + 7, scopeChain, callFrame, 0, argCount, asObject(v));
@@ -3529,13 +3562,13 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
 
             JSValue returnValue;
             {
-                SamplingTool::HostCallRecord callRecord(m_sampler);
+                SamplingTool::HostCallRecord callRecord(m_sampler.get());
                 returnValue = constructData.native.function(newCallFrame, asObject(v), args);
             }
             CHECK_FOR_EXCEPTION();
             callFrame->r(dst) = JSValue(returnValue);
 
-            vPC += 7;
+            vPC += OPCODE_LENGTH(op_construct);
             NEXT_INSTRUCTION();
         }
 
@@ -3553,32 +3586,33 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
 
         int dst = vPC[1].u.operand;
         if (LIKELY(callFrame->r(dst).jsValue().isObject())) {
-            vPC += 3;
+            vPC += OPCODE_LENGTH(op_construct_verify);
             NEXT_INSTRUCTION();
         }
 
         int override = vPC[2].u.operand;
         callFrame->r(dst) = callFrame->r(override);
 
-        vPC += 3;
+        vPC += OPCODE_LENGTH(op_construct_verify);
         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_strcat) {
-        int dst = (++vPC)->u.operand;
-        int src = (++vPC)->u.operand;
-        int count = (++vPC)->u.operand;
+        int dst = vPC[1].u.operand;
+        int src = vPC[2].u.operand;
+        int count = vPC[3].u.operand;
 
-        callFrame->r(dst) = concatenateStrings(callFrame, &callFrame->registers()[src], count);
-        ++vPC;
+        callFrame->r(dst) = jsString(callFrame, &callFrame->registers()[src], count);
+        CHECK_FOR_EXCEPTION();
+        vPC += OPCODE_LENGTH(op_strcat);
 
         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_to_primitive) {
-        int dst = (++vPC)->u.operand;
-        int src = (++vPC)->u.operand;
+        int dst = vPC[1].u.operand;
+        int src = vPC[2].u.operand;
 
         callFrame->r(dst) = callFrame->r(src).jsValue().toPrimitive(callFrame);
-        ++vPC;
+        vPC += OPCODE_LENGTH(op_to_primitive);
 
         NEXT_INSTRUCTION();
     }
@@ -3589,7 +3623,7 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
            of the current scope chain.  The contents of the register scope
            are replaced by the result of toObject conversion of the scope.
         */
-        int scope = (++vPC)->u.operand;
+        int scope = vPC[1].u.operand;
         JSValue v = callFrame->r(scope).jsValue();
         JSObject* o = v.toObject(callFrame);
         CHECK_FOR_EXCEPTION();
@@ -3597,7 +3631,7 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
         callFrame->r(scope) = JSValue(o);
         callFrame->setScopeChain(callFrame->scopeChain()->push(o));
 
-        ++vPC;
+        vPC += OPCODE_LENGTH(op_push_scope);
         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_pop_scope) {
@@ -3607,47 +3641,69 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
         */
         callFrame->setScopeChain(callFrame->scopeChain()->pop());
 
-        ++vPC;
+        vPC += OPCODE_LENGTH(op_pop_scope);
         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_get_pnames) {
-        /* get_pnames dst(r) base(r)
+        /* get_pnames dst(r) base(r) i(n) size(n) breakTarget(offset)
 
            Creates a property name list for register base and puts it
-           in register dst. This is not a true JavaScript value, just
-           a synthetic value used to keep the iteration state in a
-           register.
+           in register dst, initializing i and size for iteration. If
+           base is undefined or null, jumps to breakTarget.
         */
-        int dst = (++vPC)->u.operand;
-        int base = (++vPC)->u.operand;
+        int dst = vPC[1].u.operand;
+        int base = vPC[2].u.operand;
+        int i = vPC[3].u.operand;
+        int size = vPC[4].u.operand;
+        int breakTarget = vPC[5].u.operand;
+
+        JSValue v = callFrame->r(base).jsValue();
+        if (v.isUndefinedOrNull()) {
+            vPC += breakTarget;
+            NEXT_INSTRUCTION();
+        }
 
-        callFrame->r(dst) = JSPropertyNameIterator::create(callFrame, callFrame->r(base).jsValue());
-        ++vPC;
+        JSObject* o = v.toObject(callFrame);
+        Structure* structure = o->structure();
+        JSPropertyNameIterator* jsPropertyNameIterator = structure->enumerationCache();
+        if (!jsPropertyNameIterator || jsPropertyNameIterator->cachedPrototypeChain() != structure->prototypeChain(callFrame))
+            jsPropertyNameIterator = JSPropertyNameIterator::create(callFrame, o);
+
+        callFrame->r(dst) = jsPropertyNameIterator;
+        callFrame->r(base) = JSValue(o);
+        callFrame->r(i) = Register::withInt(0);
+        callFrame->r(size) = Register::withInt(jsPropertyNameIterator->size());
+        vPC += OPCODE_LENGTH(op_get_pnames);
         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_next_pname) {
-        /* next_pname dst(r) iter(r) target(offset)
+        /* next_pname dst(r) base(r) i(n) size(n) iter(r) target(offset)
 
-           Tries to copies the next name from property name list in
-           register iter. If there are names left, then copies one to
-           register dst, and jumps to offset target. If there are none
-           left, invalidates the iterator and continues to the next
+           Copies the next name from the property name list in
+           register iter to dst, then jumps to offset target. If there are no
+           names left, invalidates the iterator and continues to the next
            instruction.
         */
-        int dst = (++vPC)->u.operand;
-        int iter = (++vPC)->u.operand;
-        int target = (++vPC)->u.operand;
+        int dst = vPC[1].u.operand;
+        int base = vPC[2].u.operand;
+        int i = vPC[3].u.operand;
+        int size = vPC[4].u.operand;
+        int iter = vPC[5].u.operand;
+        int target = vPC[6].u.operand;
 
         JSPropertyNameIterator* it = callFrame->r(iter).propertyNameIterator();
-        if (JSValue temp = it->next(callFrame)) {
-            CHECK_FOR_TIMEOUT();
-            callFrame->r(dst) = JSValue(temp);
-            vPC += target;
-            NEXT_INSTRUCTION();
+        while (callFrame->r(i).i() != callFrame->r(size).i()) {
+            JSValue key = it->get(callFrame, asObject(callFrame->r(base).jsValue()), callFrame->r(i).i());
+            callFrame->r(i) = Register::withInt(callFrame->r(i).i() + 1);
+            if (key) {
+                CHECK_FOR_TIMEOUT();
+                callFrame->r(dst) = key;
+                vPC += target;
+                NEXT_INSTRUCTION();
+            }
         }
-        it->invalidate();
 
-        ++vPC;
+        vPC += OPCODE_LENGTH(op_next_pname);
         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_jmp_scopes) {
@@ -3657,8 +3713,8 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
            specified by immediate number count, then jumps to offset
            target.
         */
-        int count = (++vPC)->u.operand;
-        int target = (++vPC)->u.operand;
+        int count = vPC[1].u.operand;
+        int target = vPC[2].u.operand;
 
         ScopeChainNode* tmp = callFrame->scopeChain();
         while (count--)
@@ -3681,7 +3737,7 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
          */
         callFrame->setScopeChain(createExceptionScope(callFrame, vPC));
 
-        vPC += 4;
+        vPC += OPCODE_LENGTH(op_push_new_scope);
         NEXT_INSTRUCTION();
     }
 #if HAVE(COMPUTED_GOTO)
@@ -3706,11 +3762,11 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
         }
 #endif
 
-        int ex = (++vPC)->u.operand;
+        int ex = vPC[1].u.operand;
         callFrame->r(ex) = exceptionValue;
         exceptionValue = JSValue();
 
-        ++vPC;
+        vPC += OPCODE_LENGTH(op_catch);
         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_throw) {
@@ -3724,7 +3780,7 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
            else the script returns control to the nearest native caller.
         */
 
-        int ex = (++vPC)->u.operand;
+        int ex = vPC[1].u.operand;
         exceptionValue = callFrame->r(ex).jsValue();
 
         handler = throwException(callFrame, exceptionValue, vPC - callFrame->codeBlock()->instructions().begin(), true);
@@ -3744,14 +3800,14 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
            constant message as the message string. The result is
            written to register dst.
         */
-        int dst = (++vPC)->u.operand;
-        int type = (++vPC)->u.operand;
-        int message = (++vPC)->u.operand;
+        int dst = vPC[1].u.operand;
+        int type = vPC[2].u.operand;
+        int message = vPC[3].u.operand;
 
         CodeBlock* codeBlock = callFrame->codeBlock();
         callFrame->r(dst) = JSValue(Error::create(callFrame, (ErrorType)type, callFrame->r(message).jsValue().toString(callFrame), codeBlock->lineNumberForBytecodeOffset(callFrame, vPC - codeBlock->instructions().begin()), codeBlock->ownerExecutable()->sourceID(), codeBlock->ownerExecutable()->sourceURL()));
 
-        ++vPC;
+        vPC += OPCODE_LENGTH(op_new_error);
         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_end) {
@@ -3766,7 +3822,7 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
             ASSERT(scopeChain->refCount > 1);
             scopeChain->deref();
         }
-        int result = (++vPC)->u.operand;
+        int result = vPC[1].u.operand;
         return callFrame->r(result).jsValue();
     }
     DEFINE_OPCODE(op_put_getter) {
@@ -3780,9 +3836,9 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
            Unlike many opcodes, this one does not write any output to
            the register file.
         */
-        int base = (++vPC)->u.operand;
-        int property = (++vPC)->u.operand;
-        int function = (++vPC)->u.operand;
+        int base = vPC[1].u.operand;
+        int property = vPC[2].u.operand;
+        int function = vPC[3].u.operand;
 
         ASSERT(callFrame->r(base).jsValue().isObject());
         JSObject* baseObj = asObject(callFrame->r(base).jsValue());
@@ -3790,7 +3846,7 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
         ASSERT(callFrame->r(function).jsValue().isObject());
         baseObj->defineGetter(callFrame, ident, asObject(callFrame->r(function).jsValue()));
 
-        ++vPC;
+        vPC += OPCODE_LENGTH(op_put_getter);
         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_put_setter) {
@@ -3804,9 +3860,9 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
            Unlike many opcodes, this one does not write any output to
            the register file.
         */
-        int base = (++vPC)->u.operand;
-        int property = (++vPC)->u.operand;
-        int function = (++vPC)->u.operand;
+        int base = vPC[1].u.operand;
+        int property = vPC[2].u.operand;
+        int function = vPC[3].u.operand;
 
         ASSERT(callFrame->r(base).jsValue().isObject());
         JSObject* baseObj = asObject(callFrame->r(base).jsValue());
@@ -3814,7 +3870,7 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
         ASSERT(callFrame->r(function).jsValue().isObject());
         baseObj->defineSetter(callFrame, ident, asObject(callFrame->r(function).jsValue()), 0);
 
-        ++vPC;
+        vPC += OPCODE_LENGTH(op_put_setter);
         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_method_check) {
@@ -3827,9 +3883,9 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
            Places the address of the next instruction into the retAddrDst
            register and jumps to offset target from the current instruction.
         */
-        int retAddrDst = (++vPC)->u.operand;
-        int target = (++vPC)->u.operand;
-        callFrame->r(retAddrDst) = vPC + 1;
+        int retAddrDst = vPC[1].u.operand;
+        int target = vPC[2].u.operand;
+        callFrame->r(retAddrDst) = vPC + OPCODE_LENGTH(op_jsr);
 
         vPC += target;
         NEXT_INSTRUCTION();
@@ -3841,24 +3897,23 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
          differs from op_jmp because the target address is stored in a
          register, not as an immediate.
         */
-        int retAddrSrc = (++vPC)->u.operand;
+        int retAddrSrc = vPC[1].u.operand;
         vPC = callFrame->r(retAddrSrc).vPC();
         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_debug) {
-        /* debug debugHookID(n) firstLine(n) lastLine(n) columnNumber(n)
+        /* debug debugHookID(n) firstLine(n) lastLine(n)
 
          Notifies the debugger of the current state of execution. This opcode
          is only generated while the debugger is attached.
         */
-        int debugHookID = (++vPC)->u.operand;
-        int firstLine = (++vPC)->u.operand;
-        int lastLine = (++vPC)->u.operand;
-        int column = (++vPC)->u.operand;
+        int debugHookID = vPC[1].u.operand;
+        int firstLine = vPC[2].u.operand;
+        int lastLine = vPC[3].u.operand;
 
-        debug(callFrame, static_cast<DebugHookID>(debugHookID), firstLine, lastLine, column);
+        debug(callFrame, static_cast<DebugHookID>(debugHookID), firstLine, lastLine);
 
-        ++vPC;
+        vPC += OPCODE_LENGTH(op_debug);
         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_profile_will_call) {
@@ -3872,7 +3927,7 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
         if (*enabledProfilerReference)
             (*enabledProfilerReference)->willExecute(callFrame, callFrame->r(function).jsValue());
 
-        vPC += 2;
+        vPC += OPCODE_LENGTH(op_profile_will_call);
         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_profile_did_call) {
@@ -3886,7 +3941,7 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
         if (*enabledProfilerReference)
             (*enabledProfilerReference)->didExecute(callFrame, callFrame->r(function).jsValue());
 
-        vPC += 2;
+        vPC += OPCODE_LENGTH(op_profile_did_call);
         NEXT_INSTRUCTION();
     }
     vm_throw: {
@@ -3992,4 +4047,40 @@ CallFrame* Interpreter::findFunctionCallFrame(CallFrame* callFrame, InternalFunc
     return 0;
 }
 
+void Interpreter::enableSampler()
+{
+#if ENABLE(OPCODE_SAMPLING)
+    if (!m_sampler) {
+        m_sampler.set(new SamplingTool(this));
+        m_sampler->setup();
+    }
+#endif
+}
+void Interpreter::dumpSampleData(ExecState* exec)
+{
+#if ENABLE(OPCODE_SAMPLING)
+    if (m_sampler)
+        m_sampler->dump(exec);
+#else
+    UNUSED_PARAM(exec);
+#endif
+}
+void Interpreter::startSampling()
+{
+#if ENABLE(SAMPLING_THREAD)
+    if (!m_sampleEntryDepth)
+        SamplingThread::start();
+
+    m_sampleEntryDepth++;
+#endif
+}
+void Interpreter::stopSampling()
+{
+#if ENABLE(SAMPLING_THREAD)
+    m_sampleEntryDepth--;
+    if (!m_sampleEntryDepth)
+        SamplingThread::stop();
+#endif
+}
+
 } // namespace JSC
diff --git a/src/3rdparty/javascriptcore/JavaScriptCore/interpreter/Interpreter.h b/src/3rdparty/javascriptcore/JavaScriptCore/interpreter/Interpreter.h
index 157e0c7..e17b055 100644
--- a/src/3rdparty/javascriptcore/JavaScriptCore/interpreter/Interpreter.h
+++ b/src/3rdparty/javascriptcore/JavaScriptCore/interpreter/Interpreter.h
@@ -105,13 +105,15 @@ namespace JSC {
         
         void getArgumentsData(CallFrame*, JSFunction*&, ptrdiff_t& firstParameterIndex, Register*& argv, int& argc);
         
-        void setSampler(SamplingTool* sampler) { m_sampler = sampler; }
-        SamplingTool* sampler() { return m_sampler; }
+        SamplingTool* sampler() { return m_sampler.get(); }
 
         NEVER_INLINE JSValue callEval(CallFrame*, RegisterFile*, Register* argv, int argc, int registerOffset, JSValue& exceptionValue);
         NEVER_INLINE HandlerInfo* throwException(CallFrame*&, JSValue&, unsigned bytecodeOffset, bool);
-        NEVER_INLINE void debug(CallFrame*, DebugHookID, int firstLine, int lastLine, int column);
+        NEVER_INLINE void debug(CallFrame*, DebugHookID, int firstLine, int lastLine);
 
+        void dumpSampleData(ExecState* exec);
+        void startSampling();
+        void stopSampling();
     private:
         enum ExecutionFlag { Normal, InitializeAndReturn };
 
@@ -127,7 +129,6 @@ namespace JSC {
         NEVER_INLINE bool resolveGlobal(CallFrame*, Instruction*, JSValue& exceptionValue);
         NEVER_INLINE void resolveBase(CallFrame*, Instruction* vPC);
         NEVER_INLINE bool resolveBaseAndProperty(CallFrame*, Instruction*, JSValue& exceptionValue);
-        NEVER_INLINE bool resolveBaseAndFunc(CallFrame*, Instruction*, JSValue& exceptionValue);
         NEVER_INLINE ScopeChainNode* createExceptionScope(CallFrame*, const Instruction* vPC);
 
         void tryCacheGetByID(CallFrame*, CodeBlock*, Instruction*, JSValue baseValue, const Identifier& propertyName, const PropertySlot&);
@@ -149,7 +150,9 @@ namespace JSC {
         
         bool isCallBytecode(Opcode opcode) { return opcode == getOpcode(op_call) || opcode == getOpcode(op_construct) || opcode == getOpcode(op_call_eval); }
 
-        SamplingTool* m_sampler;
+        void enableSampler();
+        int m_sampleEntryDepth;
+        OwnPtr<SamplingTool> m_sampler;
 
         int m_reentryDepth;
 
diff --git a/src/3rdparty/javascriptcore/JavaScriptCore/interpreter/Register.h b/src/3rdparty/javascriptcore/JavaScriptCore/interpreter/Register.h
index ea1f849..3486fa7 100644
--- a/src/3rdparty/javascriptcore/JavaScriptCore/interpreter/Register.h
+++ b/src/3rdparty/javascriptcore/JavaScriptCore/interpreter/Register.h
@@ -50,17 +50,18 @@ namespace JSC {
     class Register : public WTF::FastAllocBase {
     public:
         Register();
-        Register(JSValue);
 
+        Register(const JSValue&);
+        Register& operator=(const JSValue&);
         JSValue jsValue() const;
         
-        Register(JSActivation*);
-        Register(CallFrame*);
-        Register(CodeBlock*);
-        Register(JSObject*);
-        Register(JSPropertyNameIterator*);
-        Register(ScopeChainNode*);
-        Register(Instruction*);
+        Register& operator=(JSActivation*);
+        Register& operator=(CallFrame*);
+        Register& operator=(CodeBlock*);
+        Register& operator=(JSObject*);
+        Register& operator=(JSPropertyNameIterator*);
+        Register& operator=(ScopeChainNode*);
+        Register& operator=(Instruction*);
 
         int32_t i() const;
         JSActivation* activation() const;
@@ -74,12 +75,12 @@ namespace JSC {
 
         static Register withInt(int32_t i)
         {
-            return Register(i);
+            Register r;
+            r.u.i = i;
+            return r;
         }
 
     private:
-        Register(int32_t);
-
         union {
             int32_t i;
             EncodedJSValue value;
@@ -97,13 +98,25 @@ namespace JSC {
     ALWAYS_INLINE Register::Register()
     {
 #ifndef NDEBUG
-        u.value = JSValue::encode(JSValue());
+        *this = JSValue();
+#endif
+    }
+
+    ALWAYS_INLINE Register::Register(const JSValue& v)
+    {
+#if ENABLE(JSC_ZOMBIES)
+        ASSERT(!v.isZombie());
 #endif
+        u.value = JSValue::encode(v);
     }
 
-    ALWAYS_INLINE Register::Register(JSValue v)
+    ALWAYS_INLINE Register& Register::operator=(const JSValue& v)
     {
+#if ENABLE(JSC_ZOMBIES)
+        ASSERT(!v.isZombie());
+#endif
         u.value = JSValue::encode(v);
+        return *this;
     }
 
     ALWAYS_INLINE JSValue Register::jsValue() const
@@ -113,44 +126,46 @@ namespace JSC {
 
     // Interpreter functions
 
-    ALWAYS_INLINE Register::Register(JSActivation* activation)
+    ALWAYS_INLINE Register& Register::operator=(JSActivation* activation)
     {
         u.activation = activation;
+        return *this;
     }
 
-    ALWAYS_INLINE Register::Register(CallFrame* callFrame)
+    ALWAYS_INLINE Register& Register::operator=(CallFrame* callFrame)
     {
         u.callFrame = callFrame;
+        return *this;
     }
 
-    ALWAYS_INLINE Register::Register(CodeBlock* codeBlock)
+    ALWAYS_INLINE Register& Register::operator=(CodeBlock* codeBlock)
     {
         u.codeBlock = codeBlock;
+        return *this;
     }
 
-    ALWAYS_INLINE Register::Register(JSObject* object)
+    ALWAYS_INLINE Register& Register::operator=(JSObject* object)
     {
         u.object = object;
+        return *this;
     }
 
-    ALWAYS_INLINE Register::Register(Instruction* vPC)
+    ALWAYS_INLINE Register& Register::operator=(Instruction* vPC)
     {
         u.vPC = vPC;
+        return *this;
     }
 
-    ALWAYS_INLINE Register::Register(ScopeChainNode* scopeChain)
+    ALWAYS_INLINE Register& Register::operator=(ScopeChainNode* scopeChain)
     {
         u.scopeChain = scopeChain;
+        return *this;
     }
 
-    ALWAYS_INLINE Register::Register(JSPropertyNameIterator* propertyNameIterator)
+    ALWAYS_INLINE Register& Register::operator=(JSPropertyNameIterator* propertyNameIterator)
     {
         u.propertyNameIterator = propertyNameIterator;
-    }
-
-    ALWAYS_INLINE Register::Register(int32_t i)
-    {
-        u.i = i;
+        return *this;
     }
 
     ALWAYS_INLINE int32_t Register::i() const
diff --git a/src/3rdparty/javascriptcore/JavaScriptCore/interpreter/RegisterFile.cpp b/src/3rdparty/javascriptcore/JavaScriptCore/interpreter/RegisterFile.cpp
index de5175e..939573b 100644
--- a/src/3rdparty/javascriptcore/JavaScriptCore/interpreter/RegisterFile.cpp
+++ b/src/3rdparty/javascriptcore/JavaScriptCore/interpreter/RegisterFile.cpp
@@ -36,7 +36,7 @@ RegisterFile::~RegisterFile()
 #if HAVE(MMAP)
     munmap(reinterpret_cast<char*>(m_buffer), ((m_max - m_start) + m_maxGlobals) * sizeof(Register));
 #elif HAVE(VIRTUALALLOC)
-#if PLATFORM(WINCE)
+#if OS(WINCE)
     VirtualFree(m_buffer, DWORD(m_commitEnd) - DWORD(m_buffer), MEM_DECOMMIT);
 #endif
     VirtualFree(m_buffer, 0, MEM_RELEASE);
diff --git a/src/3rdparty/javascriptcore/JavaScriptCore/interpreter/RegisterFile.h b/src/3rdparty/javascriptcore/JavaScriptCore/interpreter/RegisterFile.h
index 0eeff0e..34e2504 100644
--- a/src/3rdparty/javascriptcore/JavaScriptCore/interpreter/RegisterFile.h
+++ b/src/3rdparty/javascriptcore/JavaScriptCore/interpreter/RegisterFile.h
@@ -176,7 +176,7 @@ namespace JSC {
     #if HAVE(MMAP)
         m_buffer = reinterpret_cast<Register*>(mmap(0, bufferLength, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANON, VM_TAG_FOR_REGISTERFILE_MEMORY, 0));
         if (m_buffer == MAP_FAILED) {
-#if PLATFORM(WINCE)
+#if OS(WINCE)
             fprintf(stderr, "Could not allocate register file: %d\n", GetLastError());
 #else
             fprintf(stderr, "Could not allocate register file: %d\n", errno);
@@ -186,7 +186,7 @@ namespace JSC {
     #elif HAVE(VIRTUALALLOC)
         m_buffer = static_cast<Register*>(VirtualAlloc(0, roundUpAllocationSize(bufferLength, commitSize), MEM_RESERVE, PAGE_READWRITE));
         if (!m_buffer) {
-#if PLATFORM(WINCE)
+#if OS(WINCE)
             fprintf(stderr, "Could not allocate register file: %d\n", GetLastError());
 #else
             fprintf(stderr, "Could not allocate register file: %d\n", errno);
@@ -196,7 +196,7 @@ namespace JSC {
         size_t committedSize = roundUpAllocationSize(maxGlobals * sizeof(Register), commitSize);
         void* commitCheck = VirtualAlloc(m_buffer, committedSize, MEM_COMMIT, PAGE_READWRITE);
         if (commitCheck != m_buffer) {
-#if PLATFORM(WINCE)
+#if OS(WINCE)
             fprintf(stderr, "Could not allocate register file: %d\n", GetLastError());
 #else
             fprintf(stderr, "Could not allocate register file: %d\n", errno);
@@ -242,7 +242,7 @@ namespace JSC {
         if (newEnd > m_commitEnd) {
             size_t size = roundUpAllocationSize(reinterpret_cast<char*>(newEnd) - reinterpret_cast<char*>(m_commitEnd), commitSize);
             if (!VirtualAlloc(m_commitEnd, size, MEM_COMMIT, PAGE_READWRITE)) {
-#if PLATFORM(WINCE)
+#if OS(WINCE)
                 fprintf(stderr, "Could not allocate register file: %d\n", GetLastError());
 #else
                 fprintf(stderr, "Could not allocate register file: %d\n", errno);