JavaScriptCore-903.tar.gz

[apple/javascriptcore.git] / interpreter / Interpreter.cpp

diff --git a/interpreter/Interpreter.cpp b/interpreter/Interpreter.cpp
index 9821c510be84a8dd792d3d4a01252e7ab8a10e43..1514933f90b332b38941d7dcb955ac4c7536726d 100644 (file)
--- a/interpreter/Interpreter.cpp
+++ b/interpreter/Interpreter.cpp
@@ -35,13 +35,13 @@
 #include "CallFrame.h"
 #include "CallFrameClosure.h"
 #include "CodeBlock.h"
 #include "CallFrame.h"
 #include "CallFrameClosure.h"
 #include "CodeBlock.h"

-#include "Collector.h"
+#include "Heap.h"

 #include "Debugger.h"
 #include "DebuggerCallFrame.h"
 #include "Debugger.h"
 #include "DebuggerCallFrame.h"

+#include "ErrorInstance.h"

 #include "EvalCodeCache.h"
 #include "ExceptionHelpers.h"
 #include "GetterSetter.h"
 #include "EvalCodeCache.h"
 #include "ExceptionHelpers.h"
 #include "GetterSetter.h"

-#include "GlobalEvalFunction.h"

 #include "JSActivation.h"
 #include "JSArray.h"
 #include "JSByteArray.h"
 #include "JSActivation.h"
 #include "JSArray.h"
 #include "JSByteArray.h"


@@ -59,6 +59,8 @@
 #include "RegExpPrototype.h"
 #include "Register.h"
 #include "SamplingTool.h"
 #include "RegExpPrototype.h"
 #include "Register.h"
 #include "SamplingTool.h"

+#include "StrictEvalActivation.h"
+#include "UStringConcatenate.h"

 #include <limits.h>
 #include <stdio.h>
 #include <wtf/Threading.h>
 #include <limits.h>
 #include <stdio.h>
 #include <wtf/Threading.h>


@@ -72,27 +74,13 @@
 using namespace std;
 
 namespace JSC {
 using namespace std;
 
 namespace JSC {

-    
-#if ENABLE(JIT)
-    static ALWAYS_INLINE unsigned bytecodeOffsetForPC(CallFrame* callFrame, CodeBlock* codeBlock, ReturnAddressPtr pc)
-    {
-        return codeBlock->getBytecodeIndex(callFrame, ReturnAddressPtr(pc));
-    }
-#endif
-#if ENABLE(INTERPRETER)
-    static ALWAYS_INLINE unsigned bytecodeOffsetForPC(CallFrame* callFrame, CodeBlock* codeBlock, Instruction* pc)
-    {
-        UNUSED_PARAM(callFrame);
-        return pc - codeBlock->instructions().begin();
-    }
-#endif

 
 // Returns the depth of the scope chain within a given call frame.
 
 // Returns the depth of the scope chain within a given call frame.

-static int depth(CodeBlock* codeBlock, ScopeChain& sc)
+static int depth(CodeBlock* codeBlock, ScopeChainNode* sc)

 {
     if (!codeBlock->needsFullScopeChain())
         return 0;
 {
     if (!codeBlock->needsFullScopeChain())
         return 0;

-    return sc.localDepth();
+    return sc->localDepth();

 }
 
 #if ENABLE(INTERPRETER) 
 }
 
 #if ENABLE(INTERPRETER) 


@@ -114,18 +102,18 @@ NEVER_INLINE bool Interpreter::resolve(CallFrame* callFrame, Instruction* vPC, J
     CodeBlock* codeBlock = callFrame->codeBlock();
     Identifier& ident = codeBlock->identifier(property);
     do {
     CodeBlock* codeBlock = callFrame->codeBlock();
     Identifier& ident = codeBlock->identifier(property);
     do {

-        JSObject* o = *iter;
+        JSObject* o = iter->get();

         PropertySlot slot(o);
         if (o->getPropertySlot(callFrame, ident, slot)) {
             JSValue result = slot.getValue(callFrame, ident);
             exceptionValue = callFrame->globalData().exception;
             if (exceptionValue)
                 return false;
         PropertySlot slot(o);
         if (o->getPropertySlot(callFrame, ident, slot)) {
             JSValue result = slot.getValue(callFrame, ident);
             exceptionValue = callFrame->globalData().exception;
             if (exceptionValue)
                 return false;

-            callFrame->r(dst) = JSValue(result);
+            callFrame->uncheckedR(dst) = JSValue(result);

             return true;
         }
     } while (++iter != end);
             return true;
         }
     } while (++iter != end);

-    exceptionValue = createUndefinedVariableError(callFrame, ident, vPC - codeBlock->instructions().begin(), codeBlock);
+    exceptionValue = createUndefinedVariableError(callFrame, ident);

     return false;
 }
 
     return false;
 }
 


@@ -135,90 +123,100 @@ NEVER_INLINE bool Interpreter::resolveSkip(CallFrame* callFrame, Instruction* vP
 
     int dst = vPC[1].u.operand;
     int property = vPC[2].u.operand;
 
     int dst = vPC[1].u.operand;
     int property = vPC[2].u.operand;

-    int skip = vPC[3].u.operand + codeBlock->needsFullScopeChain();
+    int skip = vPC[3].u.operand;

 
     ScopeChainNode* scopeChain = callFrame->scopeChain();
     ScopeChainIterator iter = scopeChain->begin();
     ScopeChainIterator end = scopeChain->end();
     ASSERT(iter != end);
 
     ScopeChainNode* scopeChain = callFrame->scopeChain();
     ScopeChainIterator iter = scopeChain->begin();
     ScopeChainIterator end = scopeChain->end();
     ASSERT(iter != end);

+    bool checkTopLevel = codeBlock->codeType() == FunctionCode && codeBlock->needsFullScopeChain();
+    ASSERT(skip || !checkTopLevel);
+    if (checkTopLevel && skip--) {
+        if (callFrame->uncheckedR(codeBlock->activationRegister()).jsValue())
+            ++iter;
+    }

     while (skip--) {
         ++iter;
         ASSERT(iter != end);
     }
     Identifier& ident = codeBlock->identifier(property);
     do {
     while (skip--) {
         ++iter;
         ASSERT(iter != end);
     }
     Identifier& ident = codeBlock->identifier(property);
     do {

-        JSObject* o = *iter;
+        JSObject* o = iter->get();

         PropertySlot slot(o);
         if (o->getPropertySlot(callFrame, ident, slot)) {
             JSValue result = slot.getValue(callFrame, ident);
             exceptionValue = callFrame->globalData().exception;
             if (exceptionValue)
                 return false;
         PropertySlot slot(o);
         if (o->getPropertySlot(callFrame, ident, slot)) {
             JSValue result = slot.getValue(callFrame, ident);
             exceptionValue = callFrame->globalData().exception;
             if (exceptionValue)
                 return false;

-            callFrame->r(dst) = JSValue(result);
+            ASSERT(result);
+            callFrame->uncheckedR(dst) = JSValue(result);

             return true;
         }
     } while (++iter != end);
             return true;
         }
     } while (++iter != end);

-    exceptionValue = createUndefinedVariableError(callFrame, ident, vPC - codeBlock->instructions().begin(), codeBlock);
+    exceptionValue = createUndefinedVariableError(callFrame, ident);

     return false;
 }
 
 NEVER_INLINE bool Interpreter::resolveGlobal(CallFrame* callFrame, Instruction* vPC, JSValue& exceptionValue)
 {
     int dst = vPC[1].u.operand;
     return false;
 }
 
 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);
+    CodeBlock* codeBlock = callFrame->codeBlock();
+    JSGlobalObject* globalObject = codeBlock->globalObject();

     ASSERT(globalObject->isGlobalObject());
     ASSERT(globalObject->isGlobalObject());

-    int property = vPC[3].u.operand;
-    Structure* structure = vPC[4].u.structure;
-    int offset = vPC[5].u.operand;
+    int property = vPC[2].u.operand;
+    Structure* structure = vPC[3].u.structure.get();
+    int offset = vPC[4].u.operand;

 
     if (structure == globalObject->structure()) {
 
     if (structure == globalObject->structure()) {

-        callFrame->r(dst) = JSValue(globalObject->getDirectOffset(offset));
+        callFrame->uncheckedR(dst) = JSValue(globalObject->getDirectOffset(offset));

         return true;
     }
 
         return true;
     }
 

-    CodeBlock* codeBlock = callFrame->codeBlock();

     Identifier& ident = codeBlock->identifier(property);
     PropertySlot slot(globalObject);
     if (globalObject->getPropertySlot(callFrame, ident, slot)) {
         JSValue result = slot.getValue(callFrame, ident);
         if (slot.isCacheableValue() && !globalObject->structure()->isUncacheableDictionary() && slot.slotBase() == globalObject) {
     Identifier& ident = codeBlock->identifier(property);
     PropertySlot slot(globalObject);
     if (globalObject->getPropertySlot(callFrame, ident, slot)) {
         JSValue result = slot.getValue(callFrame, ident);
         if (slot.isCacheableValue() && !globalObject->structure()->isUncacheableDictionary() && slot.slotBase() == globalObject) {

-            if (vPC[4].u.structure)
-                vPC[4].u.structure->deref();
-            globalObject->structure()->ref();
-            vPC[4] = globalObject->structure();
-            vPC[5] = slot.cachedOffset();
-            callFrame->r(dst) = JSValue(result);
+            vPC[3].u.structure.set(callFrame->globalData(), codeBlock->ownerExecutable(), globalObject->structure());
+            vPC[4] = slot.cachedOffset();
+            callFrame->uncheckedR(dst) = JSValue(result);

             return true;
         }
 
         exceptionValue = callFrame->globalData().exception;
         if (exceptionValue)
             return false;
             return true;
         }
 
         exceptionValue = callFrame->globalData().exception;
         if (exceptionValue)
             return false;

-        callFrame->r(dst) = JSValue(result);
+        callFrame->uncheckedR(dst) = JSValue(result);

         return true;
     }
 
         return true;
     }
 

-    exceptionValue = createUndefinedVariableError(callFrame, ident, vPC - codeBlock->instructions().begin(), codeBlock);
+    exceptionValue = createUndefinedVariableError(callFrame, ident);

     return false;
 }
 
 NEVER_INLINE bool Interpreter::resolveGlobalDynamic(CallFrame* callFrame, Instruction* vPC, JSValue& exceptionValue)
 {
     int dst = vPC[1].u.operand;
     return false;
 }
 
 NEVER_INLINE bool Interpreter::resolveGlobalDynamic(CallFrame* callFrame, Instruction* vPC, JSValue& exceptionValue)
 {
     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;

     CodeBlock* codeBlock = callFrame->codeBlock();
     CodeBlock* codeBlock = callFrame->codeBlock();

-    int skip = vPC[6].u.operand + codeBlock->needsFullScopeChain();
+    JSGlobalObject* globalObject = codeBlock->globalObject();
+    ASSERT(globalObject->isGlobalObject());
+    int property = vPC[2].u.operand;
+    Structure* structure = vPC[3].u.structure.get();
+    int offset = vPC[4].u.operand;
+    int skip = vPC[5].u.operand;

     
     ScopeChainNode* scopeChain = callFrame->scopeChain();
     ScopeChainIterator iter = scopeChain->begin();
     ScopeChainIterator end = scopeChain->end();
     ASSERT(iter != end);
     
     ScopeChainNode* scopeChain = callFrame->scopeChain();
     ScopeChainIterator iter = scopeChain->begin();
     ScopeChainIterator end = scopeChain->end();
     ASSERT(iter != end);

+    bool checkTopLevel = codeBlock->codeType() == FunctionCode && codeBlock->needsFullScopeChain();
+    ASSERT(skip || !checkTopLevel);
+    if (checkTopLevel && skip--) {
+        if (callFrame->uncheckedR(codeBlock->activationRegister()).jsValue())
+            ++iter;
+    }

     while (skip--) {
     while (skip--) {

-        JSObject* o = *iter;
+        JSObject* o = iter->get();

         if (o->hasCustomProperties()) {
             Identifier& ident = codeBlock->identifier(property);
             do {
         if (o->hasCustomProperties()) {
             Identifier& ident = codeBlock->identifier(property);
             do {


@@ -228,22 +226,24 @@ NEVER_INLINE bool Interpreter::resolveGlobalDynamic(CallFrame* callFrame, Instru
                     exceptionValue = callFrame->globalData().exception;
                     if (exceptionValue)
                         return false;
                     exceptionValue = callFrame->globalData().exception;
                     if (exceptionValue)
                         return false;

-                    callFrame->r(dst) = JSValue(result);
+                    ASSERT(result);
+                    callFrame->uncheckedR(dst) = JSValue(result);

                     return true;
                 }
                 if (iter == end)
                     break;
                     return true;
                 }
                 if (iter == end)
                     break;

-                o = *iter;
+                o = iter->get();

                 ++iter;
             } while (true);
                 ++iter;
             } while (true);

-            exceptionValue = createUndefinedVariableError(callFrame, ident, vPC - codeBlock->instructions().begin(), codeBlock);
+            exceptionValue = createUndefinedVariableError(callFrame, ident);

             return false;
         }
         ++iter;
     }
     
     if (structure == globalObject->structure()) {
             return false;
         }
         ++iter;
     }
     
     if (structure == globalObject->structure()) {

-        callFrame->r(dst) = JSValue(globalObject->getDirectOffset(offset));
+        callFrame->uncheckedR(dst) = JSValue(globalObject->getDirectOffset(offset));
+        ASSERT(callFrame->uncheckedR(dst).jsValue());

         return true;
     }
 
         return true;
     }
 


@@ -252,23 +252,22 @@ NEVER_INLINE bool Interpreter::resolveGlobalDynamic(CallFrame* callFrame, Instru
     if (globalObject->getPropertySlot(callFrame, ident, slot)) {
         JSValue result = slot.getValue(callFrame, ident);
         if (slot.isCacheableValue() && !globalObject->structure()->isUncacheableDictionary() && slot.slotBase() == globalObject) {
     if (globalObject->getPropertySlot(callFrame, ident, slot)) {
         JSValue result = slot.getValue(callFrame, ident);
         if (slot.isCacheableValue() && !globalObject->structure()->isUncacheableDictionary() && slot.slotBase() == globalObject) {

-            if (vPC[4].u.structure)
-                vPC[4].u.structure->deref();
-            globalObject->structure()->ref();
-            vPC[4] = globalObject->structure();
-            vPC[5] = slot.cachedOffset();
-            callFrame->r(dst) = JSValue(result);
+            vPC[3].u.structure.set(callFrame->globalData(), codeBlock->ownerExecutable(), globalObject->structure());
+            vPC[4] = slot.cachedOffset();
+            ASSERT(result);
+            callFrame->uncheckedR(dst) = JSValue(result);

             return true;
         }
         
         exceptionValue = callFrame->globalData().exception;
         if (exceptionValue)
             return false;
             return true;
         }
         
         exceptionValue = callFrame->globalData().exception;
         if (exceptionValue)
             return false;

-        callFrame->r(dst) = JSValue(result);
+        ASSERT(result);
+        callFrame->uncheckedR(dst) = JSValue(result);

         return true;
     }
     
         return true;
     }
     

-    exceptionValue = createUndefinedVariableError(callFrame, ident, vPC - codeBlock->instructions().begin(), codeBlock);
+    exceptionValue = createUndefinedVariableError(callFrame, ident);

     return false;
 }
 
     return false;
 }
 


@@ -276,7 +275,14 @@ NEVER_INLINE void Interpreter::resolveBase(CallFrame* callFrame, Instruction* vP
 {
     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()));
+    bool isStrictPut = vPC[3].u.operand;
+    Identifier ident = callFrame->codeBlock()->identifier(property);
+    JSValue result = JSC::resolveBase(callFrame, ident, callFrame->scopeChain(), isStrictPut);
+    if (result) {
+        callFrame->uncheckedR(dst) = result;
+        ASSERT(callFrame->uncheckedR(dst).jsValue());
+    } else
+        callFrame->globalData().exception = createErrorForInvalidGlobalAssignment(callFrame, ident.ustring());

 }
 
 NEVER_INLINE bool Interpreter::resolveBaseAndProperty(CallFrame* callFrame, Instruction* vPC, JSValue& exceptionValue)
 }
 
 NEVER_INLINE bool Interpreter::resolveBaseAndProperty(CallFrame* callFrame, Instruction* vPC, JSValue& exceptionValue)


@@ -297,21 +303,21 @@ NEVER_INLINE bool Interpreter::resolveBaseAndProperty(CallFrame* callFrame, Inst
     Identifier& ident = codeBlock->identifier(property);
     JSObject* base;
     do {
     Identifier& ident = codeBlock->identifier(property);
     JSObject* base;
     do {

-        base = *iter;
+        base = iter->get();

         PropertySlot slot(base);
         if (base->getPropertySlot(callFrame, ident, slot)) {
             JSValue result = slot.getValue(callFrame, ident);
             exceptionValue = callFrame->globalData().exception;
             if (exceptionValue)
                 return false;
         PropertySlot slot(base);
         if (base->getPropertySlot(callFrame, ident, slot)) {
             JSValue result = slot.getValue(callFrame, ident);
             exceptionValue = callFrame->globalData().exception;
             if (exceptionValue)
                 return false;

-            callFrame->r(propDst) = JSValue(result);
-            callFrame->r(baseDst) = JSValue(base);
+            callFrame->uncheckedR(propDst) = JSValue(result);
+            callFrame->uncheckedR(baseDst) = JSValue(base);

             return true;
         }
         ++iter;
     } while (iter != end);
 
             return true;
         }
         ++iter;
     } while (iter != end);
 

-    exceptionValue = createUndefinedVariableError(callFrame, ident, vPC - codeBlock->instructions().begin(), codeBlock);
+    exceptionValue = createUndefinedVariableError(callFrame, ident);

     return false;
 }
 
     return false;
 }
 


@@ -355,24 +361,24 @@ ALWAYS_INLINE CallFrame* Interpreter::slideRegisterWindowForCall(CodeBlock* newC
 }
 
 #if ENABLE(INTERPRETER)
 }
 
 #if ENABLE(INTERPRETER)

-static NEVER_INLINE bool isInvalidParamForIn(CallFrame* callFrame, CodeBlock* codeBlock, const Instruction* vPC, JSValue value, JSValue& exceptionData)
+static NEVER_INLINE bool isInvalidParamForIn(CallFrame* callFrame, JSValue value, JSValue& exceptionData)

 {
     if (value.isObject())
         return false;
 {
     if (value.isObject())
         return false;

-    exceptionData = createInvalidParamError(callFrame, "in" , value, vPC - codeBlock->instructions().begin(), codeBlock);
+    exceptionData = createInvalidParamError(callFrame, "in" , value);

     return true;
 }
 
     return true;
 }
 

-static NEVER_INLINE bool isInvalidParamForInstanceOf(CallFrame* callFrame, CodeBlock* codeBlock, const Instruction* vPC, JSValue value, JSValue& exceptionData)
+static NEVER_INLINE bool isInvalidParamForInstanceOf(CallFrame* callFrame, JSValue value, JSValue& exceptionData)

 {
     if (value.isObject() && asObject(value)->structure()->typeInfo().implementsHasInstance())
         return false;
 {
     if (value.isObject() && asObject(value)->structure()->typeInfo().implementsHasInstance())
         return false;

-    exceptionData = createInvalidParamError(callFrame, "instanceof" , value, vPC - codeBlock->instructions().begin(), codeBlock);
+    exceptionData = createInvalidParamError(callFrame, "instanceof" , value);

     return true;
 }
 #endif
 
     return true;
 }
 #endif
 

-NEVER_INLINE JSValue Interpreter::callEval(CallFrame* callFrame, RegisterFile* registerFile, Register* argv, int argc, int registerOffset, JSValue& exceptionValue)
+NEVER_INLINE JSValue Interpreter::callEval(CallFrame* callFrame, RegisterFile* registerFile, Register* argv, int argc, int registerOffset)

 {
     if (argc < 2)
         return jsUndefined();
 {
     if (argc < 2)
         return jsUndefined();


@@ -385,28 +391,34 @@ NEVER_INLINE JSValue Interpreter::callEval(CallFrame* callFrame, RegisterFile* r
     UString programSource = asString(program)->value(callFrame);
     if (callFrame->hadException())
         return JSValue();
     UString programSource = asString(program)->value(callFrame);
     if (callFrame->hadException())
         return JSValue();

-
-    LiteralParser preparser(callFrame, programSource, LiteralParser::NonStrictJSON);
-    if (JSValue parsedObject = preparser.tryLiteralParse())
-        return parsedObject;
+    
+    CodeBlock* codeBlock = callFrame->codeBlock();
+    if (!codeBlock->isStrictMode()) {
+        // FIXME: We can use the preparser in strict mode, we just need additional logic
+        // to prevent duplicates.
+        LiteralParser preparser(callFrame, programSource.characters(), programSource.length(), LiteralParser::NonStrictJSON);
+        if (JSValue parsedObject = preparser.tryLiteralParse())
+            return parsedObject;
+    }

 
     ScopeChainNode* scopeChain = callFrame->scopeChain();
 
     ScopeChainNode* scopeChain = callFrame->scopeChain();

-    CodeBlock* codeBlock = callFrame->codeBlock();
-    RefPtr<EvalExecutable> eval = codeBlock->evalCodeCache().get(callFrame, programSource, scopeChain, exceptionValue);
+    JSValue exceptionValue;
+    EvalExecutable* eval = codeBlock->evalCodeCache().get(callFrame, codeBlock->ownerExecutable(), codeBlock->isStrictMode(), programSource, scopeChain, exceptionValue);

 
 

-    JSValue result = jsUndefined();
-    if (eval)
-        result = callFrame->globalData().interpreter->execute(eval.get(), callFrame, callFrame->thisValue().toThisObject(callFrame), callFrame->registers() - registerFile->start() + registerOffset, scopeChain, &exceptionValue);
+    ASSERT(!eval == exceptionValue);
+    if (UNLIKELY(!eval))
+        return throwError(callFrame, exceptionValue);

 
 

-    return result;
+    return callFrame->globalData().interpreter->execute(eval, callFrame, callFrame->uncheckedR(codeBlock->thisRegister()).jsValue().toThisObject(callFrame), callFrame->registers() - registerFile->start() + registerOffset, scopeChain);

 }
 
 }
 

-Interpreter::Interpreter()
+Interpreter::Interpreter(JSGlobalData& globalData)

     : m_sampleEntryDepth(0)
     , m_reentryDepth(0)
     : m_sampleEntryDepth(0)
     , m_reentryDepth(0)

+    , m_registerFile(globalData)

 {
 #if ENABLE(COMPUTED_GOTO_INTERPRETER)
 {
 #if ENABLE(COMPUTED_GOTO_INTERPRETER)

-    privateExecute(InitializeAndReturn, 0, 0, 0);
+    privateExecute(InitializeAndReturn, 0, 0);

 
     for (int i = 0; i < numOpcodeIDs; ++i)
         m_opcodeIDTable.add(m_opcodeTable[i], static_cast<OpcodeID>(i));
 
     for (int i = 0; i < numOpcodeIDs; ++i)
         m_opcodeIDTable.add(m_opcodeTable[i], static_cast<OpcodeID>(i));


@@ -433,7 +445,7 @@ void Interpreter::dumpRegisters(CallFrame* callFrame)
     printf("-----------------------------------------------------------------------------\n");
 
     CodeBlock* codeBlock = callFrame->codeBlock();
     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;
     const Register* it;
     const Register* end;
     JSValue v;


@@ -477,10 +489,8 @@ void Interpreter::dumpRegisters(CallFrame* callFrame)
     printf("[ScopeChain]               | %10p | %p \n", it, (*it).scopeChain()); ++it;
     printf("[CallerRegisters]          | %10p | %d \n", it, (*it).i()); ++it;
     printf("[ReturnPC]                 | %10p | %p \n", it, (*it).vPC()); ++it;
     printf("[ScopeChain]               | %10p | %p \n", it, (*it).scopeChain()); ++it;
     printf("[CallerRegisters]          | %10p | %d \n", it, (*it).i()); ++it;
     printf("[ReturnPC]                 | %10p | %p \n", it, (*it).vPC()); ++it;

-    printf("[ReturnValueRegister]      | %10p | %d \n", it, (*it).i()); ++it;

     printf("[ArgumentCount]            | %10p | %d \n", it, (*it).i()); ++it;
     printf("[Callee]                   | %10p | %p \n", it, (*it).function()); ++it;
     printf("[ArgumentCount]            | %10p | %d \n", it, (*it).i()); ++it;
     printf("[Callee]                   | %10p | %p \n", it, (*it).function()); ++it;

-    printf("[OptionalCalleeArguments]  | %10p | %p \n", it, (*it).arguments()); ++it;

     printf("-----------------------------------------------------------------------------\n");
 
     int registerCount = 0;
     printf("-----------------------------------------------------------------------------\n");
 
     int registerCount = 0;


@@ -542,135 +552,167 @@ NEVER_INLINE bool Interpreter::unwindCallFrame(CallFrame*& callFrame, JSValue ex
             debugger->didExecuteProgram(debuggerCallFrame, codeBlock->ownerExecutable()->sourceID(), codeBlock->ownerExecutable()->lastLine());
     }
 
             debugger->didExecuteProgram(debuggerCallFrame, codeBlock->ownerExecutable()->sourceID(), codeBlock->ownerExecutable()->lastLine());
     }
 

-    if (Profiler* profiler = *Profiler::enabledProfilerReference()) {
-        if (callFrame->callee())
-            profiler->didExecute(callFrame, callFrame->callee());
-        else
-            profiler->didExecute(callFrame, codeBlock->ownerExecutable()->sourceURL(), codeBlock->ownerExecutable()->lineNo());
-    }
-

     // If this call frame created an activation or an 'arguments' object, tear it off.
     if (oldCodeBlock->codeType() == FunctionCode && oldCodeBlock->needsFullScopeChain()) {
     // If this call frame created an activation or an 'arguments' object, tear it off.
     if (oldCodeBlock->codeType() == FunctionCode && oldCodeBlock->needsFullScopeChain()) {

-        while (!scopeChain->object->inherits(&JSActivation::info))
+        if (!callFrame->uncheckedR(oldCodeBlock->activationRegister()).jsValue()) {
+            oldCodeBlock->createActivation(callFrame);
+            scopeChain = callFrame->scopeChain();
+        }
+        while (!scopeChain->object->inherits(&JSActivation::s_info))

             scopeChain = scopeChain->pop();
             scopeChain = scopeChain->pop();

-        static_cast<JSActivation*>(scopeChain->object)->copyRegisters(callFrame->optionalCalleeArguments());
-    } else if (Arguments* arguments = callFrame->optionalCalleeArguments()) {
-        if (!arguments->isTornOff())
-            arguments->copyRegisters();
-    }

 
 

-    if (oldCodeBlock->needsFullScopeChain())
-        scopeChain->deref();
+        callFrame->setScopeChain(scopeChain);
+        JSActivation* activation = asActivation(scopeChain->object.get());
+        activation->copyRegisters(*scopeChain->globalData);
+        if (JSValue arguments = callFrame->uncheckedR(unmodifiedArgumentsRegister(oldCodeBlock->argumentsRegister())).jsValue()) {
+            if (!oldCodeBlock->isStrictMode())
+                asArguments(arguments)->setActivation(callFrame->globalData(), activation);
+        }
+    } else if (oldCodeBlock->usesArguments() && !oldCodeBlock->isStrictMode()) {
+        if (JSValue arguments = callFrame->uncheckedR(unmodifiedArgumentsRegister(oldCodeBlock->argumentsRegister())).jsValue())
+            asArguments(arguments)->copyRegisters(callFrame->globalData());
+    }

 
 

-    ExecState* callerFrame = callFrame->callerFrame();
+    CallFrame* callerFrame = callFrame->callerFrame();

     if (callerFrame->hasHostCallFrameFlag())
         return false;
 
     codeBlock = callerFrame->codeBlock();
     if (callerFrame->hasHostCallFrameFlag())
         return false;
 
     codeBlock = callerFrame->codeBlock();

-#if ENABLE(JIT)
-#if ENABLE(INTERPRETER)
+    
+    // Because of how the JIT records call site->bytecode offset
+    // information the JIT reports the bytecodeOffset for the returnPC
+    // to be at the beginning of the opcode that has caused the call.
+    // In the interpreter we have an actual return address, which is
+    // the beginning of next instruction to execute. To get an offset
+    // inside the call instruction that triggered the exception we
+    // have to subtract 1.
+#if ENABLE(JIT) && ENABLE(INTERPRETER)

     if (callerFrame->globalData().canUseJIT())
     if (callerFrame->globalData().canUseJIT())

-#endif
-        bytecodeOffset = bytecodeOffsetForPC(callerFrame, codeBlock, callFrame->returnPC());
-#if ENABLE(INTERPRETER)
+        bytecodeOffset = codeBlock->bytecodeOffset(callFrame->returnPC());

     else
     else

-        bytecodeOffset = bytecodeOffsetForPC(callerFrame, codeBlock, callFrame->returnVPC());
-#endif
+        bytecodeOffset = codeBlock->bytecodeOffset(callFrame->returnVPC()) - 1;
+#elif ENABLE(JIT)
+    bytecodeOffset = codeBlock->bytecodeOffset(callFrame->returnPC());

 #else
 #else

-    bytecodeOffset = codeBlock->bytecodeOffset(callerFrame, callFrame->returnVPC());
+    bytecodeOffset = codeBlock->bytecodeOffset(callFrame->returnVPC()) - 1;

 #endif
 #endif

+

     callFrame = callerFrame;
     return true;
 }
 
     callFrame = callerFrame;
     return true;
 }
 

-NEVER_INLINE HandlerInfo* Interpreter::throwException(CallFrame*& callFrame, JSValue& exceptionValue, unsigned bytecodeOffset, bool explicitThrow)
+static void appendSourceToError(CallFrame* callFrame, ErrorInstance* exception, unsigned bytecodeOffset)

 {
 {

-    // Set up the exception object
+    exception->clearAppendSourceToMessage();
+
+    if (!callFrame->codeBlock()->hasExpressionInfo())
+        return;
+
+    int startOffset = 0;
+    int endOffset = 0;
+    int divotPoint = 0;
+
+    CodeBlock* codeBlock = callFrame->codeBlock();
+    codeBlock->expressionRangeForBytecodeOffset(bytecodeOffset, divotPoint, startOffset, endOffset);
+
+    int expressionStart = divotPoint - startOffset;
+    int expressionStop = divotPoint + endOffset;
+
+    if (!expressionStop || expressionStart > codeBlock->source()->length())
+        return;
+
+    JSGlobalData* globalData = &callFrame->globalData();
+    JSValue jsMessage = exception->getDirect(*globalData, globalData->propertyNames->message);
+    if (!jsMessage || !jsMessage.isString())
+        return;
+
+    UString message = asString(jsMessage)->value(callFrame);
+
+    if (expressionStart < expressionStop)
+        message =  makeUString(message, " (evaluating '", codeBlock->source()->getRange(expressionStart, expressionStop), "')");
+    else {
+        // No range information, so give a few characters of context
+        const UChar* data = codeBlock->source()->data();
+        int dataLength = codeBlock->source()->length();
+        int start = expressionStart;
+        int stop = expressionStart;
+        // Get up to 20 characters of context to the left and right of the divot, clamping to the line.
+        // then strip whitespace.
+        while (start > 0 && (expressionStart - start < 20) && data[start - 1] != '\n')
+            start--;
+        while (start < (expressionStart - 1) && isStrWhiteSpace(data[start]))
+            start++;
+        while (stop < dataLength && (stop - expressionStart < 20) && data[stop] != '\n')
+            stop++;
+        while (stop > expressionStart && isStrWhiteSpace(data[stop - 1]))
+            stop--;
+        message = makeUString(message, " (near '...", codeBlock->source()->getRange(start, stop), "...')");
+    }
+
+    exception->putDirect(*globalData, globalData->propertyNames->message, jsString(globalData, message));
+}

 
 

+NEVER_INLINE HandlerInfo* Interpreter::throwException(CallFrame*& callFrame, JSValue& exceptionValue, unsigned bytecodeOffset)
+{

     CodeBlock* codeBlock = callFrame->codeBlock();
     CodeBlock* codeBlock = callFrame->codeBlock();

+    bool isInterrupt = false;
+
+    // Set up the exception object

     if (exceptionValue.isObject()) {
         JSObject* exception = asObject(exceptionValue);
     if (exceptionValue.isObject()) {
         JSObject* exception = asObject(exceptionValue);

-        if (exception->isNotAnObjectErrorStub()) {
-            exception = createNotAnObjectError(callFrame, static_cast<JSNotAnObjectErrorStub*>(exception), bytecodeOffset, codeBlock);
-            exceptionValue = exception;
-        } else {
-            if (!exception->hasProperty(callFrame, Identifier(callFrame, "line")) && 
-                !exception->hasProperty(callFrame, Identifier(callFrame, "sourceId")) && 
-                !exception->hasProperty(callFrame, Identifier(callFrame, "sourceURL")) && 
-                !exception->hasProperty(callFrame, Identifier(callFrame, expressionBeginOffsetPropertyName)) && 
-                !exception->hasProperty(callFrame, Identifier(callFrame, expressionCaretOffsetPropertyName)) && 
-                !exception->hasProperty(callFrame, Identifier(callFrame, expressionEndOffsetPropertyName))) {
-                if (explicitThrow) {
-                    int startOffset = 0;
-                    int endOffset = 0;
-                    int divotPoint = 0;
-                    int line = codeBlock->expressionRangeForBytecodeOffset(callFrame, bytecodeOffset, divotPoint, startOffset, endOffset);
-                    exception->putWithAttributes(callFrame, Identifier(callFrame, "line"), jsNumber(callFrame, line), ReadOnly | DontDelete);
-                    
-                    // We only hit this path for error messages and throw statements, which don't have a specific failure position
-                    // So we just give the full range of the error/throw statement.
-                    exception->putWithAttributes(callFrame, Identifier(callFrame, expressionBeginOffsetPropertyName), jsNumber(callFrame, divotPoint - startOffset), ReadOnly | DontDelete);
-                    exception->putWithAttributes(callFrame, Identifier(callFrame, expressionEndOffsetPropertyName), jsNumber(callFrame, divotPoint + endOffset), ReadOnly | DontDelete);
-                } else
-                    exception->putWithAttributes(callFrame, Identifier(callFrame, "line"), jsNumber(callFrame, codeBlock->lineNumberForBytecodeOffset(callFrame, bytecodeOffset)), ReadOnly | DontDelete);
-                exception->putWithAttributes(callFrame, Identifier(callFrame, "sourceId"), jsNumber(callFrame, codeBlock->ownerExecutable()->sourceID()), ReadOnly | DontDelete);
-                exception->putWithAttributes(callFrame, Identifier(callFrame, "sourceURL"), jsOwnedString(callFrame, codeBlock->ownerExecutable()->sourceURL()), ReadOnly | DontDelete);
-            }

 
 

-            ComplType exceptionType = exception->exceptionType();
-            if (exceptionType == Interrupted || exceptionType == Terminated) {
-                while (unwindCallFrame(callFrame, exceptionValue, bytecodeOffset, codeBlock)) {
-                    // Don't need handler checks or anything, we just want to unroll all the JS callframes possible.
-                }
-                return 0;
-            }
+        if (exception->isErrorInstance() && static_cast<ErrorInstance*>(exception)->appendSourceToMessage())
+            appendSourceToError(callFrame, static_cast<ErrorInstance*>(exception), bytecodeOffset);
+
+        // Using hasExpressionInfo to imply we are interested in rich exception info.
+        if (codeBlock->hasExpressionInfo() && !hasErrorInfo(callFrame, exception)) {
+            ASSERT(codeBlock->hasLineInfo());
+
+            // FIXME: should only really be adding these properties to VM generated exceptions,
+            // but the inspector currently requires these for all thrown objects.
+            addErrorInfo(callFrame, exception, codeBlock->lineNumberForBytecodeOffset(bytecodeOffset), codeBlock->ownerExecutable()->source());

         }
         }

+
+        ComplType exceptionType = exception->exceptionType();
+        isInterrupt = exceptionType == Interrupted || exceptionType == Terminated;

     }
 
     if (Debugger* debugger = callFrame->dynamicGlobalObject()->debugger()) {
         DebuggerCallFrame debuggerCallFrame(callFrame, exceptionValue);
         bool hasHandler = codeBlock->handlerForBytecodeOffset(bytecodeOffset);
     }
 
     if (Debugger* debugger = callFrame->dynamicGlobalObject()->debugger()) {
         DebuggerCallFrame debuggerCallFrame(callFrame, exceptionValue);
         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
-    // the profiler manually that the call instruction has returned, since
-    // we'll never reach the relevant op_profile_did_call.
-    if (Profiler* profiler = *Profiler::enabledProfilerReference()) {
-#if ENABLE(INTERPRETER)
-        if (!callFrame->globalData().canUseJIT()) {
-            // FIXME: Why 8? - work out what this magic value is, replace the constant with something more helpful.
-            if (isCallBytecode(codeBlock->instructions()[bytecodeOffset].u.opcode))
-                profiler->didExecute(callFrame, callFrame->r(codeBlock->instructions()[bytecodeOffset + 1].u.operand).jsValue());
-            else if (codeBlock->instructions().size() > (bytecodeOffset + 8) && codeBlock->instructions()[bytecodeOffset + 8].u.opcode == getOpcode(op_construct))
-                profiler->didExecute(callFrame, callFrame->r(codeBlock->instructions()[bytecodeOffset + 9].u.operand).jsValue());
-        }
-#if ENABLE(JIT)
-        else
-#endif
-#endif
-#if ENABLE(JIT)
-        {
-            int functionRegisterIndex;
-            if (codeBlock->functionRegisterForBytecodeOffset(bytecodeOffset, functionRegisterIndex))
-                profiler->didExecute(callFrame, callFrame->r(functionRegisterIndex).jsValue());
-        }
-#endif
+        debugger->exception(debuggerCallFrame, codeBlock->ownerExecutable()->sourceID(), codeBlock->lineNumberForBytecodeOffset(bytecodeOffset), hasHandler);

     }
 
     // Calculate an exception handler vPC, unwinding call frames as necessary.
     }
 
     // Calculate an exception handler vPC, unwinding call frames as necessary.

-

     HandlerInfo* handler = 0;
     HandlerInfo* handler = 0;

-    while (!(handler = codeBlock->handlerForBytecodeOffset(bytecodeOffset))) {
-        if (!unwindCallFrame(callFrame, exceptionValue, bytecodeOffset, codeBlock))
+    while (isInterrupt || !(handler = codeBlock->handlerForBytecodeOffset(bytecodeOffset))) {
+        if (!unwindCallFrame(callFrame, exceptionValue, bytecodeOffset, codeBlock)) {
+            if (Profiler* profiler = *Profiler::enabledProfilerReference())
+                profiler->exceptionUnwind(callFrame);

             return 0;
             return 0;

+        }

     }
 
     }
 

-    // Now unwind the scope chain within the exception handler's call frame.
+    if (Profiler* profiler = *Profiler::enabledProfilerReference())
+        profiler->exceptionUnwind(callFrame);

 
 

+    // Shrink the JS stack, in case stack overflow made it huge.
+    Register* highWaterMark = 0;
+    for (CallFrame* callerFrame = callFrame; callerFrame; callerFrame = callerFrame->callerFrame()->removeHostCallFrameFlag()) {
+        CodeBlock* codeBlock = callerFrame->codeBlock();
+        if (!codeBlock)
+            continue;
+        Register* callerHighWaterMark = callerFrame->registers() + codeBlock->m_numCalleeRegisters;
+        highWaterMark = max(highWaterMark, callerHighWaterMark);
+    }
+    m_registerFile.shrink(highWaterMark);
+
+    // Unwind the scope chain within the exception handler's call frame.

     ScopeChainNode* scopeChain = callFrame->scopeChain();
     ScopeChainNode* scopeChain = callFrame->scopeChain();

-    ScopeChain sc(scopeChain);
-    int scopeDelta = depth(codeBlock, sc) - handler->scopeDepth;
+    int scopeDelta = 0;
+    if (!codeBlock->needsFullScopeChain() || codeBlock->codeType() != FunctionCode 
+        || callFrame->uncheckedR(codeBlock->activationRegister()).jsValue())
+        scopeDelta = depth(codeBlock, scopeChain) - handler->scopeDepth;

     ASSERT(scopeDelta >= 0);
     while (scopeDelta--)
         scopeChain = scopeChain->pop();
     ASSERT(scopeDelta >= 0);
     while (scopeDelta--)
         scopeChain = scopeChain->pop();


@@ -679,42 +721,139 @@ NEVER_INLINE HandlerInfo* Interpreter::throwException(CallFrame*& callFrame, JSV
     return handler;
 }
 
     return handler;
 }
 

-JSValue Interpreter::execute(ProgramExecutable* program, CallFrame* callFrame, ScopeChainNode* scopeChain, JSObject* thisObj, JSValue* exception)
+static inline JSValue checkedReturn(JSValue returnValue)
+{
+    ASSERT(returnValue);
+    return returnValue;
+}
+
+static inline JSObject* checkedReturn(JSObject* returnValue)
+{
+    ASSERT(returnValue);
+    return returnValue;
+}
+
+JSValue Interpreter::execute(ProgramExecutable* program, CallFrame* callFrame, ScopeChainNode* scopeChain, JSObject* thisObj)

 {
     ASSERT(!scopeChain->globalData->exception);
 {
     ASSERT(!scopeChain->globalData->exception);

+    ASSERT(!callFrame->globalData().isCollectorBusy());
+    if (callFrame->globalData().isCollectorBusy())
+        return jsNull();

 
 

-    if (m_reentryDepth >= MaxSmallThreadReentryDepth) {
-        if (m_reentryDepth >= callFrame->globalData().maxReentryDepth) {
-            *exception = createStackOverflowError(callFrame);
-            return jsNull();
+    if (m_reentryDepth >= MaxSmallThreadReentryDepth && m_reentryDepth >= callFrame->globalData().maxReentryDepth)
+        return checkedReturn(throwStackOverflowError(callFrame));
+
+    DynamicGlobalObjectScope globalObjectScope(*scopeChain->globalData, scopeChain->globalObject.get());
+    LiteralParser literalParser(callFrame, program->source().data(), program->source().length(), LiteralParser::JSONP);
+    Vector<LiteralParser::JSONPData> JSONPData;
+    if (literalParser.tryJSONPParse(JSONPData, scopeChain->globalObject->supportsRichSourceInfo())) {
+        JSGlobalObject* globalObject = scopeChain->globalObject.get();
+        JSValue result;
+        for (unsigned entry = 0; entry < JSONPData.size(); entry++) {
+            Vector<LiteralParser::JSONPPathEntry> JSONPPath;
+            JSONPPath.swap(JSONPData[entry].m_path);
+            JSValue JSONPValue = JSONPData[entry].m_value.get();
+            if (JSONPPath.size() == 1 && JSONPPath[0].m_type == LiteralParser::JSONPPathEntryTypeDeclare) {
+                if (globalObject->hasProperty(callFrame, JSONPPath[0].m_pathEntryName)) {
+                    PutPropertySlot slot;
+                    globalObject->put(callFrame, JSONPPath[0].m_pathEntryName, JSONPValue, slot);
+                } else
+                    globalObject->putWithAttributes(callFrame, JSONPPath[0].m_pathEntryName, JSONPValue, DontEnum | DontDelete);
+                // var declarations return undefined
+                result = jsUndefined();
+                continue;
+            }
+            JSValue baseObject(globalObject);
+            for (unsigned i = 0; i < JSONPPath.size() - 1; i++) {
+                ASSERT(JSONPPath[i].m_type != LiteralParser::JSONPPathEntryTypeDeclare);
+                switch (JSONPPath[i].m_type) {
+                case LiteralParser::JSONPPathEntryTypeDot: {
+                    if (i == 0) {
+                        PropertySlot slot(globalObject);
+                        if (!globalObject->getPropertySlot(callFrame, JSONPPath[i].m_pathEntryName, slot)) {
+                            if (entry)
+                                return throwError(callFrame, createUndefinedVariableError(globalObject->globalExec(), JSONPPath[i].m_pathEntryName));
+                            goto failedJSONP;
+                        }
+                        baseObject = slot.getValue(callFrame, JSONPPath[i].m_pathEntryName);
+                    } else
+                        baseObject = baseObject.get(callFrame, JSONPPath[i].m_pathEntryName);
+                    if (callFrame->hadException())
+                        return jsUndefined();
+                    continue;
+                }
+                case LiteralParser::JSONPPathEntryTypeLookup: {
+                    baseObject = baseObject.get(callFrame, JSONPPath[i].m_pathIndex);
+                    if (callFrame->hadException())
+                        return jsUndefined();
+                    continue;
+                }
+                default:
+                    ASSERT_NOT_REACHED();
+                    return jsUndefined();
+                }
+            }
+            PutPropertySlot slot;
+            switch (JSONPPath.last().m_type) {
+            case LiteralParser::JSONPPathEntryTypeCall: {
+                JSValue function = baseObject.get(callFrame, JSONPPath.last().m_pathEntryName);
+                if (callFrame->hadException())
+                    return jsUndefined();
+                CallData callData;
+                CallType callType = getCallData(function, callData);
+                if (callType == CallTypeNone)
+                    return throwError(callFrame, createNotAFunctionError(callFrame, function));
+                MarkedArgumentBuffer jsonArg;
+                jsonArg.append(JSONPValue);
+                JSValue thisValue = JSONPPath.size() == 1 ? jsUndefined(): baseObject;
+                JSONPValue = JSC::call(callFrame, function, callType, callData, thisValue, jsonArg);
+                if (callFrame->hadException())
+                    return jsUndefined();
+                break;
+            }
+            case LiteralParser::JSONPPathEntryTypeDot: {
+                baseObject.put(callFrame, JSONPPath.last().m_pathEntryName, JSONPValue, slot);
+                if (callFrame->hadException())
+                    return jsUndefined();
+                break;
+            }
+            case LiteralParser::JSONPPathEntryTypeLookup: {
+                baseObject.put(callFrame, JSONPPath.last().m_pathIndex, JSONPValue);
+                if (callFrame->hadException())
+                    return jsUndefined();
+                break;
+            }
+            default:
+                ASSERT_NOT_REACHED();
+                    return jsUndefined();
+            }
+            result = JSONPValue;

         }
         }

+        return result;

     }
     }

-
-    CodeBlock* codeBlock = &program->bytecode(callFrame, scopeChain);
+failedJSONP:
+    JSObject* error = program->compile(callFrame, scopeChain);
+    if (error)
+        return checkedReturn(throwError(callFrame, error));
+    CodeBlock* codeBlock = &program->generatedBytecode();

 
     Register* oldEnd = m_registerFile.end();
     Register* newEnd = oldEnd + codeBlock->m_numParameters + RegisterFile::CallFrameHeaderSize + codeBlock->m_numCalleeRegisters;
 
     Register* oldEnd = m_registerFile.end();
     Register* newEnd = oldEnd + codeBlock->m_numParameters + RegisterFile::CallFrameHeaderSize + codeBlock->m_numCalleeRegisters;

-    if (!m_registerFile.grow(newEnd)) {
-        *exception = createStackOverflowError(callFrame);
-        return jsNull();
-    }
-
-    DynamicGlobalObjectScope globalObjectScope(callFrame, scopeChain->globalObject);
+    if (!m_registerFile.grow(newEnd))
+        return checkedReturn(throwStackOverflowError(callFrame));

 
     JSGlobalObject* lastGlobalObject = m_registerFile.globalObject();
     JSGlobalObject* globalObject = callFrame->dynamicGlobalObject();
     globalObject->copyGlobalsTo(m_registerFile);
 
     CallFrame* newCallFrame = CallFrame::create(oldEnd + codeBlock->m_numParameters + RegisterFile::CallFrameHeaderSize);
 
     JSGlobalObject* lastGlobalObject = m_registerFile.globalObject();
     JSGlobalObject* globalObject = callFrame->dynamicGlobalObject();
     globalObject->copyGlobalsTo(m_registerFile);
 
     CallFrame* newCallFrame = CallFrame::create(oldEnd + codeBlock->m_numParameters + RegisterFile::CallFrameHeaderSize);

-    newCallFrame->r(codeBlock->thisRegister()) = JSValue(thisObj);
-    newCallFrame->init(codeBlock, 0, scopeChain, CallFrame::noCaller(), 0, 0, 0);
-
-    if (codeBlock->needsFullScopeChain())
-        scopeChain->ref();
+    ASSERT(codeBlock->m_numParameters == 1); // 1 parameter for 'this'.
+    newCallFrame->init(codeBlock, 0, scopeChain, CallFrame::noCaller(), codeBlock->m_numParameters, 0);
+    newCallFrame->uncheckedR(newCallFrame->hostThisRegister()) = JSValue(thisObj);

 
     Profiler** profiler = Profiler::enabledProfilerReference();
     if (*profiler)
 
     Profiler** profiler = Profiler::enabledProfilerReference();
     if (*profiler)

-        (*profiler)->willExecute(newCallFrame, program->sourceURL(), program->lineNo());
+        (*profiler)->willExecute(callFrame, program->sourceURL(), program->lineNo());

 
     JSValue result;
     {
 
     JSValue result;
     {


@@ -722,17 +861,11 @@ JSValue Interpreter::execute(ProgramExecutable* program, CallFrame* callFrame, S
 
         m_reentryDepth++;  
 #if ENABLE(JIT)
 
         m_reentryDepth++;  
 #if ENABLE(JIT)

-#if ENABLE(INTERPRETER)

         if (callFrame->globalData().canUseJIT())
         if (callFrame->globalData().canUseJIT())

-#endif
-            result = program->jitCode(newCallFrame, scopeChain).execute(&m_registerFile, newCallFrame, scopeChain->globalData, exception);
-#if ENABLE(INTERPRETER)
+            result = program->generatedJITCode().execute(&m_registerFile, newCallFrame, scopeChain->globalData);

         else
 #endif
         else
 #endif

-#endif
-#if ENABLE(INTERPRETER)
-            result = privateExecute(Normal, &m_registerFile, newCallFrame, exception);
-#endif
+            result = privateExecute(Normal, &m_registerFile, newCallFrame);

 
         m_reentryDepth--;
     }
 
         m_reentryDepth--;
     }


@@ -745,46 +878,84 @@ JSValue Interpreter::execute(ProgramExecutable* program, CallFrame* callFrame, S
 
     m_registerFile.shrink(oldEnd);
 
 
     m_registerFile.shrink(oldEnd);
 

-    return result;
+    return checkedReturn(result);

 }
 
 }
 

-JSValue Interpreter::execute(FunctionExecutable* functionExecutable, CallFrame* callFrame, JSFunction* function, JSObject* thisObj, const ArgList& args, ScopeChainNode* scopeChain, JSValue* exception)
+JSValue Interpreter::executeCall(CallFrame* callFrame, JSObject* function, CallType callType, const CallData& callData, JSValue thisValue, const ArgList& args)

 {
 {

-    ASSERT(!scopeChain->globalData->exception);
+    ASSERT(!callFrame->hadException());
+    ASSERT(!callFrame->globalData().isCollectorBusy());
+    if (callFrame->globalData().isCollectorBusy())
+        return jsNull();

 
 

-    if (m_reentryDepth >= MaxSmallThreadReentryDepth) {
-        if (m_reentryDepth >= callFrame->globalData().maxReentryDepth) {
-            *exception = createStackOverflowError(callFrame);
-            return jsNull();
-        }
-    }
+    if (m_reentryDepth >= MaxSmallThreadReentryDepth && m_reentryDepth >= callFrame->globalData().maxReentryDepth)
+        return checkedReturn(throwStackOverflowError(callFrame));

 
     Register* oldEnd = m_registerFile.end();
 
     Register* oldEnd = m_registerFile.end();

-    int argc = 1 + args.size(); // implicit "this" parameter
+    int argCount = 1 + args.size(); // implicit "this" parameter
+    size_t registerOffset = argCount + RegisterFile::CallFrameHeaderSize;

 
 

-    if (!m_registerFile.grow(oldEnd + argc)) {
-        *exception = createStackOverflowError(callFrame);
-        return jsNull();
-    }
-
-    DynamicGlobalObjectScope globalObjectScope(callFrame, scopeChain->globalObject);
+    if (!m_registerFile.grow(oldEnd + registerOffset))
+        return checkedReturn(throwStackOverflowError(callFrame));

 
     CallFrame* newCallFrame = CallFrame::create(oldEnd);
     size_t dst = 0;
 
     CallFrame* newCallFrame = CallFrame::create(oldEnd);
     size_t dst = 0;

-    newCallFrame->r(0) = JSValue(thisObj);
+    newCallFrame->uncheckedR(0) = thisValue;

     ArgList::const_iterator end = args.end();
     for (ArgList::const_iterator it = args.begin(); it != end; ++it)
     ArgList::const_iterator end = args.end();
     for (ArgList::const_iterator it = args.begin(); it != end; ++it)

-        newCallFrame->r(++dst) = *it;
+        newCallFrame->uncheckedR(++dst) = *it;
+
+    if (callType == CallTypeJS) {
+        ScopeChainNode* callDataScopeChain = callData.js.scopeChain;
+
+        DynamicGlobalObjectScope globalObjectScope(*callDataScopeChain->globalData, callDataScopeChain->globalObject.get());
+
+        JSObject* compileError = callData.js.functionExecutable->compileForCall(callFrame, callDataScopeChain);
+        if (UNLIKELY(!!compileError)) {
+            m_registerFile.shrink(oldEnd);
+            return checkedReturn(throwError(callFrame, compileError));
+        }
+
+        CodeBlock* newCodeBlock = &callData.js.functionExecutable->generatedBytecodeForCall();
+        newCallFrame = slideRegisterWindowForCall(newCodeBlock, &m_registerFile, newCallFrame, registerOffset, argCount);
+        if (UNLIKELY(!newCallFrame)) {
+            m_registerFile.shrink(oldEnd);
+            return checkedReturn(throwStackOverflowError(callFrame));
+        }
+
+        newCallFrame->init(newCodeBlock, 0, callDataScopeChain, callFrame->addHostCallFrameFlag(), argCount, function);
+
+        Profiler** profiler = Profiler::enabledProfilerReference();
+        if (*profiler)
+            (*profiler)->willExecute(callFrame, function);
+
+        JSValue result;
+        {
+            SamplingTool::CallRecord callRecord(m_sampler.get());
+
+            m_reentryDepth++;  
+#if ENABLE(JIT)
+            if (callFrame->globalData().canUseJIT())
+                result = callData.js.functionExecutable->generatedJITCodeForCall().execute(&m_registerFile, newCallFrame, callDataScopeChain->globalData);
+            else
+#endif
+                result = privateExecute(Normal, &m_registerFile, newCallFrame);
+            m_reentryDepth--;
+        }
+
+        if (*profiler)
+            (*profiler)->didExecute(callFrame, function);

 
 

-    CodeBlock* codeBlock = &functionExecutable->bytecode(callFrame, scopeChain);
-    newCallFrame = slideRegisterWindowForCall(codeBlock, &m_registerFile, newCallFrame, argc + RegisterFile::CallFrameHeaderSize, argc);
-    if (UNLIKELY(!newCallFrame)) {
-        *exception = createStackOverflowError(callFrame);

         m_registerFile.shrink(oldEnd);
         m_registerFile.shrink(oldEnd);

-        return jsNull();
+        return checkedReturn(result);

     }
     }

-    // a 0 codeBlock indicates a built-in caller
-    newCallFrame->init(codeBlock, 0, scopeChain, callFrame->addHostCallFrameFlag(), 0, argc, function);
+
+    ASSERT(callType == CallTypeHost);
+    ScopeChainNode* scopeChain = callFrame->scopeChain();
+    newCallFrame = CallFrame::create(newCallFrame->registers() + registerOffset);
+    newCallFrame->init(0, 0, scopeChain, callFrame->addHostCallFrameFlag(), argCount, function);
+
+    DynamicGlobalObjectScope globalObjectScope(*scopeChain->globalData, scopeChain->globalObject.get());

 
     Profiler** profiler = Profiler::enabledProfilerReference();
     if (*profiler)
 
     Profiler** profiler = Profiler::enabledProfilerReference();
     if (*profiler)


@@ -792,38 +963,124 @@ JSValue Interpreter::execute(FunctionExecutable* functionExecutable, CallFrame*
 
     JSValue result;
     {
 
     JSValue result;
     {

-        SamplingTool::CallRecord callRecord(m_sampler.get());
+        SamplingTool::HostCallRecord callRecord(m_sampler.get());
+        result = JSValue::decode(callData.native.function(newCallFrame));
+    }

 
 

-        m_reentryDepth++;
+    if (*profiler)
+        (*profiler)->didExecute(callFrame, function);
+
+    m_registerFile.shrink(oldEnd);
+    return checkedReturn(result);
+}
+
+JSObject* Interpreter::executeConstruct(CallFrame* callFrame, JSObject* constructor, ConstructType constructType, const ConstructData& constructData, const ArgList& args)
+{
+    ASSERT(!callFrame->hadException());
+    ASSERT(!callFrame->globalData().isCollectorBusy());
+    // We throw in this case because we have to return something "valid" but we're
+    // already in an invalid state.
+    if (callFrame->globalData().isCollectorBusy())
+        return checkedReturn(throwStackOverflowError(callFrame));
+
+    if (m_reentryDepth >= MaxSmallThreadReentryDepth && m_reentryDepth >= callFrame->globalData().maxReentryDepth)
+        return checkedReturn(throwStackOverflowError(callFrame));
+
+    Register* oldEnd = m_registerFile.end();
+    int argCount = 1 + args.size(); // implicit "this" parameter
+    size_t registerOffset = argCount + RegisterFile::CallFrameHeaderSize;
+
+    if (!m_registerFile.grow(oldEnd + registerOffset))
+        return checkedReturn(throwStackOverflowError(callFrame));
+
+    CallFrame* newCallFrame = CallFrame::create(oldEnd);
+    size_t dst = 0;
+    ArgList::const_iterator end = args.end();
+    for (ArgList::const_iterator it = args.begin(); it != end; ++it)
+        newCallFrame->uncheckedR(++dst) = *it;
+
+    if (constructType == ConstructTypeJS) {
+        ScopeChainNode* constructDataScopeChain = constructData.js.scopeChain;
+
+        DynamicGlobalObjectScope globalObjectScope(*constructDataScopeChain->globalData, constructDataScopeChain->globalObject.get());
+
+        JSObject* compileError = constructData.js.functionExecutable->compileForConstruct(callFrame, constructDataScopeChain);
+        if (UNLIKELY(!!compileError)) {
+            m_registerFile.shrink(oldEnd);
+            return checkedReturn(throwError(callFrame, compileError));
+        }
+
+        CodeBlock* newCodeBlock = &constructData.js.functionExecutable->generatedBytecodeForConstruct();
+        newCallFrame = slideRegisterWindowForCall(newCodeBlock, &m_registerFile, newCallFrame, registerOffset, argCount);
+        if (UNLIKELY(!newCallFrame)) {
+            m_registerFile.shrink(oldEnd);
+            return checkedReturn(throwStackOverflowError(callFrame));
+        }
+
+        newCallFrame->init(newCodeBlock, 0, constructDataScopeChain, callFrame->addHostCallFrameFlag(), argCount, constructor);
+
+        Profiler** profiler = Profiler::enabledProfilerReference();
+        if (*profiler)
+            (*profiler)->willExecute(callFrame, constructor);
+
+        JSValue result;
+        {
+            SamplingTool::CallRecord callRecord(m_sampler.get());
+
+            m_reentryDepth++;  

 #if ENABLE(JIT)
 #if ENABLE(JIT)

-#if ENABLE(INTERPRETER)
-        if (scopeChain->globalData->canUseJIT())
-#endif
-            result = functionExecutable->jitCode(newCallFrame, scopeChain).execute(&m_registerFile, newCallFrame, scopeChain->globalData, exception);
-#if ENABLE(INTERPRETER)
-        else
-#endif
-#endif
-#if ENABLE(INTERPRETER)
-        result = privateExecute(Normal, &m_registerFile, newCallFrame, exception);
+            if (callFrame->globalData().canUseJIT())
+                result = constructData.js.functionExecutable->generatedJITCodeForConstruct().execute(&m_registerFile, newCallFrame, constructDataScopeChain->globalData);
+            else

 #endif
 #endif

-        m_reentryDepth--;
+                result = privateExecute(Normal, &m_registerFile, newCallFrame);
+            m_reentryDepth--;
+        }
+
+        if (*profiler)
+            (*profiler)->didExecute(callFrame, constructor);
+
+        m_registerFile.shrink(oldEnd);
+        if (callFrame->hadException())
+            return 0;
+        ASSERT(result.isObject());
+        return checkedReturn(asObject(result));

     }
 
     }
 

+    ASSERT(constructType == ConstructTypeHost);
+    ScopeChainNode* scopeChain = callFrame->scopeChain();
+    newCallFrame = CallFrame::create(newCallFrame->registers() + registerOffset);
+    newCallFrame->init(0, 0, scopeChain, callFrame->addHostCallFrameFlag(), argCount, constructor);
+
+    DynamicGlobalObjectScope globalObjectScope(*scopeChain->globalData, scopeChain->globalObject.get());
+
+    Profiler** profiler = Profiler::enabledProfilerReference();

     if (*profiler)
     if (*profiler)

-        (*profiler)->didExecute(callFrame, function);
+        (*profiler)->willExecute(callFrame, constructor);
+
+    JSValue result;
+    {
+        SamplingTool::HostCallRecord callRecord(m_sampler.get());
+        result = JSValue::decode(constructData.native.function(newCallFrame));
+    }
+
+    if (*profiler)
+        (*profiler)->didExecute(callFrame, constructor);

 
     m_registerFile.shrink(oldEnd);
 
     m_registerFile.shrink(oldEnd);

-    return result;
+    if (callFrame->hadException())
+        return 0;
+    ASSERT(result.isObject());
+    return checkedReturn(asObject(result));

 }
 
 }
 

-CallFrameClosure Interpreter::prepareForRepeatCall(FunctionExecutable* FunctionExecutable, CallFrame* callFrame, JSFunction* function, int argCount, ScopeChainNode* scopeChain, JSValue* exception)
+CallFrameClosure Interpreter::prepareForRepeatCall(FunctionExecutable* FunctionExecutable, CallFrame* callFrame, JSFunction* function, int argCount, ScopeChainNode* scopeChain)

 {
     ASSERT(!scopeChain->globalData->exception);
     
     if (m_reentryDepth >= MaxSmallThreadReentryDepth) {
         if (m_reentryDepth >= callFrame->globalData().maxReentryDepth) {
 {
     ASSERT(!scopeChain->globalData->exception);
     
     if (m_reentryDepth >= MaxSmallThreadReentryDepth) {
         if (m_reentryDepth >= callFrame->globalData().maxReentryDepth) {

-            *exception = createStackOverflowError(callFrame);
+            throwStackOverflowError(callFrame);

             return CallFrameClosure();
         }
     }
             return CallFrameClosure();
         }
     }


@@ -832,36 +1089,40 @@ CallFrameClosure Interpreter::prepareForRepeatCall(FunctionExecutable* FunctionE
     int argc = 1 + argCount; // implicit "this" parameter
     
     if (!m_registerFile.grow(oldEnd + argc)) {
     int argc = 1 + argCount; // implicit "this" parameter
     
     if (!m_registerFile.grow(oldEnd + argc)) {

-        *exception = createStackOverflowError(callFrame);
+        throwStackOverflowError(callFrame);

         return CallFrameClosure();
     }
 
     CallFrame* newCallFrame = CallFrame::create(oldEnd);
         return CallFrameClosure();
     }
 
     CallFrame* newCallFrame = CallFrame::create(oldEnd);

+    // We initialise |this| unnecessarily here for the sake of code clarity

     size_t dst = 0;
     for (int i = 0; i < argc; ++i)
     size_t dst = 0;
     for (int i = 0; i < argc; ++i)

-        newCallFrame->r(++dst) = jsUndefined();
+        newCallFrame->uncheckedR(dst++) = jsUndefined();

     
     

-    CodeBlock* codeBlock = &FunctionExecutable->bytecode(callFrame, scopeChain);
+    JSObject* error = FunctionExecutable->compileForCall(callFrame, scopeChain);
+    if (error) {
+        throwError(callFrame, error);
+        m_registerFile.shrink(oldEnd);
+        return CallFrameClosure();
+    }
+    CodeBlock* codeBlock = &FunctionExecutable->generatedBytecodeForCall();
+

     newCallFrame = slideRegisterWindowForCall(codeBlock, &m_registerFile, newCallFrame, argc + RegisterFile::CallFrameHeaderSize, argc);
     if (UNLIKELY(!newCallFrame)) {
     newCallFrame = slideRegisterWindowForCall(codeBlock, &m_registerFile, newCallFrame, argc + RegisterFile::CallFrameHeaderSize, argc);
     if (UNLIKELY(!newCallFrame)) {

-        *exception = createStackOverflowError(callFrame);
+        throwStackOverflowError(callFrame);

         m_registerFile.shrink(oldEnd);
         return CallFrameClosure();
     }
         m_registerFile.shrink(oldEnd);
         return CallFrameClosure();
     }

-    // a 0 codeBlock indicates a built-in caller
-    newCallFrame->init(codeBlock, 0, scopeChain, callFrame->addHostCallFrameFlag(), 0, argc, function);  
-#if ENABLE(JIT)
-#if ENABLE(INTERPRETER)
-    if (callFrame->globalData().canUseJIT())
-#endif
-        FunctionExecutable->jitCode(newCallFrame, scopeChain);
-#endif
+    newCallFrame->init(codeBlock, 0, scopeChain, callFrame->addHostCallFrameFlag(), argc, function);  

     CallFrameClosure result = { callFrame, newCallFrame, function, FunctionExecutable, scopeChain->globalData, oldEnd, scopeChain, codeBlock->m_numParameters, argc };
     return result;
 }
 
     CallFrameClosure result = { callFrame, newCallFrame, function, FunctionExecutable, scopeChain->globalData, oldEnd, scopeChain, codeBlock->m_numParameters, argc };
     return result;
 }
 

-JSValue Interpreter::execute(CallFrameClosure& closure, JSValue* exception) 
+JSValue Interpreter::execute(CallFrameClosure& closure) 

 {
 {

+    ASSERT(!closure.oldCallFrame->globalData().isCollectorBusy());
+    if (closure.oldCallFrame->globalData().isCollectorBusy())
+        return jsNull();

     closure.resetCallFrame();
     Profiler** profiler = Profiler::enabledProfilerReference();
     if (*profiler)
     closure.resetCallFrame();
     Profiler** profiler = Profiler::enabledProfilerReference();
     if (*profiler)


@@ -876,20 +1137,20 @@ JSValue Interpreter::execute(CallFrameClosure& closure, JSValue* exception)
 #if ENABLE(INTERPRETER)
         if (closure.newCallFrame->globalData().canUseJIT())
 #endif
 #if ENABLE(INTERPRETER)
         if (closure.newCallFrame->globalData().canUseJIT())
 #endif

-            result = closure.functionExecutable->generatedJITCode().execute(&m_registerFile, closure.newCallFrame, closure.globalData, exception);
+            result = closure.functionExecutable->generatedJITCodeForCall().execute(&m_registerFile, closure.newCallFrame, closure.globalData);

 #if ENABLE(INTERPRETER)
         else
 #endif
 #endif
 #if ENABLE(INTERPRETER)
 #if ENABLE(INTERPRETER)
         else
 #endif
 #endif
 #if ENABLE(INTERPRETER)

-            result = privateExecute(Normal, &m_registerFile, closure.newCallFrame, exception);
+            result = privateExecute(Normal, &m_registerFile, closure.newCallFrame);

 #endif
         m_reentryDepth--;
     }
     
     if (*profiler)
         (*profiler)->didExecute(closure.oldCallFrame, closure.function);
 #endif
         m_reentryDepth--;
     }
     
     if (*profiler)
         (*profiler)->didExecute(closure.oldCallFrame, closure.function);

-    return result;
+    return checkedReturn(result);

 }
 
 void Interpreter::endRepeatCall(CallFrameClosure& closure)
 }
 
 void Interpreter::endRepeatCall(CallFrameClosure& closure)


@@ -897,40 +1158,51 @@ void Interpreter::endRepeatCall(CallFrameClosure& closure)
     m_registerFile.shrink(closure.oldEnd);
 }
 
     m_registerFile.shrink(closure.oldEnd);
 }
 

-JSValue Interpreter::execute(EvalExecutable* eval, CallFrame* callFrame, JSObject* thisObj, ScopeChainNode* scopeChain, JSValue* exception)
+JSValue Interpreter::execute(EvalExecutable* eval, CallFrame* callFrame, JSObject* thisObj, ScopeChainNode* scopeChain)

 {
 {

-    return execute(eval, callFrame, thisObj, m_registerFile.size() + eval->bytecode(callFrame, scopeChain).m_numParameters + RegisterFile::CallFrameHeaderSize, scopeChain, exception);
+    JSObject* compileError = eval->compile(callFrame, scopeChain);
+    if (UNLIKELY(!!compileError))
+        return checkedReturn(throwError(callFrame, compileError));
+    return execute(eval, callFrame, thisObj, m_registerFile.size() + eval->generatedBytecode().m_numParameters + RegisterFile::CallFrameHeaderSize, scopeChain);

 }
 
 }
 

-JSValue Interpreter::execute(EvalExecutable* eval, CallFrame* callFrame, JSObject* thisObj, int globalRegisterOffset, ScopeChainNode* scopeChain, JSValue* exception)
+JSValue Interpreter::execute(EvalExecutable* eval, CallFrame* callFrame, JSObject* thisObj, int globalRegisterOffset, ScopeChainNode* scopeChain)

 {
     ASSERT(!scopeChain->globalData->exception);
 {
     ASSERT(!scopeChain->globalData->exception);

+    ASSERT(!callFrame->globalData().isCollectorBusy());
+    if (callFrame->globalData().isCollectorBusy())
+        return jsNull();

 
 

-    if (m_reentryDepth >= MaxSmallThreadReentryDepth) {
-        if (m_reentryDepth >= callFrame->globalData().maxReentryDepth) {
-            *exception = createStackOverflowError(callFrame);
-            return jsNull();
-        }
-    }
+    DynamicGlobalObjectScope globalObjectScope(*scopeChain->globalData, scopeChain->globalObject.get());

 
 

-    DynamicGlobalObjectScope globalObjectScope(callFrame, scopeChain->globalObject);
+    if (m_reentryDepth >= MaxSmallThreadReentryDepth && m_reentryDepth >= callFrame->globalData().maxReentryDepth)
+        return checkedReturn(throwStackOverflowError(callFrame));

 
 

-    EvalCodeBlock* codeBlock = &eval->bytecode(callFrame, scopeChain);
+    JSObject* compileError = eval->compile(callFrame, scopeChain);
+    if (UNLIKELY(!!compileError))
+        return checkedReturn(throwError(callFrame, compileError));
+    EvalCodeBlock* codeBlock = &eval->generatedBytecode();

 
 

-    JSVariableObject* variableObject;
-    for (ScopeChainNode* node = scopeChain; ; node = node->next) {
+    JSObject* variableObject;
+    for (ScopeChainNode* node = scopeChain; ; node = node->next.get()) {

         ASSERT(node);
         if (node->object->isVariableObject()) {
         ASSERT(node);
         if (node->object->isVariableObject()) {

-            variableObject = static_cast<JSVariableObject*>(node->object);
+            variableObject = static_cast<JSVariableObject*>(node->object.get());

             break;
         }
     }
 
     unsigned numVariables = codeBlock->numVariables();
     int numFunctions = codeBlock->numberOfFunctionDecls();
             break;
         }
     }
 
     unsigned numVariables = codeBlock->numVariables();
     int numFunctions = codeBlock->numberOfFunctionDecls();

+    bool pushedScope = false;

     if (numVariables || numFunctions) {
     if (numVariables || numFunctions) {

+        if (codeBlock->isStrictMode()) {
+            variableObject = new (callFrame) StrictEvalActivation(callFrame);
+            scopeChain = scopeChain->push(variableObject);
+            pushedScope = true;
+        }

         // Scope for BatchedTransitionOptimizer
         // Scope for BatchedTransitionOptimizer

-        BatchedTransitionOptimizer optimizer(variableObject);
+        BatchedTransitionOptimizer optimizer(callFrame->globalData(), variableObject);

 
         for (unsigned i = 0; i < numVariables; ++i) {
             const Identifier& ident = codeBlock->variable(i);
 
         for (unsigned i = 0; i < numVariables; ++i) {
             const Identifier& ident = codeBlock->variable(i);


@@ -950,22 +1222,20 @@ JSValue Interpreter::execute(EvalExecutable* eval, CallFrame* callFrame, JSObjec
     Register* oldEnd = m_registerFile.end();
     Register* newEnd = m_registerFile.start() + globalRegisterOffset + codeBlock->m_numCalleeRegisters;
     if (!m_registerFile.grow(newEnd)) {
     Register* oldEnd = m_registerFile.end();
     Register* newEnd = m_registerFile.start() + globalRegisterOffset + codeBlock->m_numCalleeRegisters;
     if (!m_registerFile.grow(newEnd)) {

-        *exception = createStackOverflowError(callFrame);
-        return jsNull();
+        if (pushedScope)
+            scopeChain->pop();
+        return checkedReturn(throwStackOverflowError(callFrame));

     }
 
     CallFrame* newCallFrame = CallFrame::create(m_registerFile.start() + globalRegisterOffset);
 
     }
 
     CallFrame* newCallFrame = CallFrame::create(m_registerFile.start() + globalRegisterOffset);
 

-    // a 0 codeBlock indicates a built-in caller
-    newCallFrame->r(codeBlock->thisRegister()) = JSValue(thisObj);
-    newCallFrame->init(codeBlock, 0, scopeChain, callFrame->addHostCallFrameFlag(), 0, 0, 0);
-
-    if (codeBlock->needsFullScopeChain())
-        scopeChain->ref();
+    ASSERT(codeBlock->m_numParameters == 1); // 1 parameter for 'this'.
+    newCallFrame->init(codeBlock, 0, scopeChain, callFrame->addHostCallFrameFlag(), codeBlock->m_numParameters, 0);
+    newCallFrame->uncheckedR(newCallFrame->hostThisRegister()) = JSValue(thisObj);

 
     Profiler** profiler = Profiler::enabledProfilerReference();
     if (*profiler)
 
     Profiler** profiler = Profiler::enabledProfilerReference();
     if (*profiler)

-        (*profiler)->willExecute(newCallFrame, eval->sourceURL(), eval->lineNo());
+        (*profiler)->willExecute(callFrame, eval->sourceURL(), eval->lineNo());

 
     JSValue result;
     {
 
     JSValue result;
     {


@@ -977,13 +1247,13 @@ JSValue Interpreter::execute(EvalExecutable* eval, CallFrame* callFrame, JSObjec
 #if ENABLE(INTERPRETER)
         if (callFrame->globalData().canUseJIT())
 #endif
 #if ENABLE(INTERPRETER)
         if (callFrame->globalData().canUseJIT())
 #endif

-            result = eval->jitCode(newCallFrame, scopeChain).execute(&m_registerFile, newCallFrame, scopeChain->globalData, exception);
+            result = eval->generatedJITCode().execute(&m_registerFile, newCallFrame, scopeChain->globalData);

 #if ENABLE(INTERPRETER)
         else
 #endif
 #endif
 #if ENABLE(INTERPRETER)
 #if ENABLE(INTERPRETER)
         else
 #endif
 #endif
 #if ENABLE(INTERPRETER)

-            result = privateExecute(Normal, &m_registerFile, newCallFrame, exception);
+            result = privateExecute(Normal, &m_registerFile, newCallFrame);

 #endif
         m_reentryDepth--;
     }
 #endif
         m_reentryDepth--;
     }


@@ -992,7 +1262,9 @@ JSValue Interpreter::execute(EvalExecutable* eval, CallFrame* callFrame, JSObjec
         (*profiler)->didExecute(callFrame, eval->sourceURL(), eval->lineNo());
 
     m_registerFile.shrink(oldEnd);
         (*profiler)->didExecute(callFrame, eval->sourceURL(), eval->lineNo());
 
     m_registerFile.shrink(oldEnd);

-    return result;
+    if (pushedScope)
+        scopeChain->pop();
+    return checkedReturn(result);

 }
 
 NEVER_INLINE void Interpreter::debug(CallFrame* callFrame, DebugHookID debugHookID, int firstLine, int lastLine)
 }
 
 NEVER_INLINE void Interpreter::debug(CallFrame* callFrame, DebugHookID debugHookID, int firstLine, int lastLine)


@@ -1031,7 +1303,7 @@ NEVER_INLINE ScopeChainNode* Interpreter::createExceptionScope(CallFrame* callFr
     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);
     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);
+    callFrame->uncheckedR(dst) = JSValue(scope);

 
     return callFrame->scopeChain()->push(scope);
 }
 
     return callFrame->scopeChain()->push(scope);
 }


@@ -1051,20 +1323,20 @@ NEVER_INLINE void Interpreter::tryCachePutByID(CallFrame* callFrame, CodeBlock*
         return;
     }
     
         return;
     }
     

-    JSCell* baseCell = asCell(baseValue);
+    JSCell* baseCell = baseValue.asCell();

     Structure* structure = baseCell->structure();
 
     Structure* structure = baseCell->structure();
 

-    if (structure->isUncacheableDictionary()) {
+    if (structure->isUncacheableDictionary() || structure->typeInfo().prohibitsPropertyCaching()) {

         vPC[0] = getOpcode(op_put_by_id_generic);
         return;
     }
 
     // Cache miss: record Structure to compare against next time.
         vPC[0] = getOpcode(op_put_by_id_generic);
         return;
     }
 
     // Cache miss: record Structure to compare against next time.

-    Structure* lastStructure = vPC[4].u.structure;
+    Structure* lastStructure = vPC[4].u.structure.get();

     if (structure != lastStructure) {
         // First miss: record Structure to compare against next time.
         if (!lastStructure) {
     if (structure != lastStructure) {
         // First miss: record Structure to compare against next time.
         if (!lastStructure) {

-            vPC[4] = structure;
+            vPC[4].u.structure.set(callFrame->globalData(), codeBlock->ownerExecutable(), structure);

             return;
         }
 
             return;
         }
 


@@ -1090,24 +1362,27 @@ NEVER_INLINE void Interpreter::tryCachePutByID(CallFrame* callFrame, CodeBlock*
 
         // put_by_id_transition checks the prototype chain for setters.
         normalizePrototypeChain(callFrame, baseCell);
 
         // put_by_id_transition checks the prototype chain for setters.
         normalizePrototypeChain(callFrame, baseCell);

-
+        JSCell* owner = codeBlock->ownerExecutable();
+        JSGlobalData& globalData = callFrame->globalData();
+        // Get the prototype here because the call to prototypeChain could cause a 
+        // GC allocation, which we don't want to happen while we're in the middle of 
+        // initializing the union.
+        StructureChain* prototypeChain = structure->prototypeChain(callFrame);

         vPC[0] = getOpcode(op_put_by_id_transition);
         vPC[0] = getOpcode(op_put_by_id_transition);

-        vPC[4] = structure->previousID();
-        vPC[5] = structure;
-        vPC[6] = structure->prototypeChain(callFrame);
+        vPC[4].u.structure.set(globalData, owner, structure->previousID());
+        vPC[5].u.structure.set(globalData, owner, structure);
+        vPC[6].u.structureChain.set(callFrame->globalData(), codeBlock->ownerExecutable(), prototypeChain);
+        ASSERT(vPC[6].u.structureChain);

         vPC[7] = slot.cachedOffset();
         vPC[7] = slot.cachedOffset();

-        codeBlock->refStructures(vPC);

         return;
     }
 
     vPC[0] = getOpcode(op_put_by_id_replace);
     vPC[5] = slot.cachedOffset();
         return;
     }
 
     vPC[0] = getOpcode(op_put_by_id_replace);
     vPC[5] = slot.cachedOffset();

-    codeBlock->refStructures(vPC);

 }
 
 }
 

-NEVER_INLINE void Interpreter::uncachePutByID(CodeBlock* codeBlock, Instruction* vPC)
+NEVER_INLINE void Interpreter::uncachePutByID(CodeBlock*, Instruction* vPC)

 {
 {

-    codeBlock->derefStructures(vPC);

     vPC[0] = getOpcode(op_put_by_id);
     vPC[4] = 0;
 }
     vPC[0] = getOpcode(op_put_by_id);
     vPC[4] = 0;
 }


@@ -1141,19 +1416,19 @@ NEVER_INLINE void Interpreter::tryCacheGetByID(CallFrame* callFrame, CodeBlock*
         return;
     }
 
         return;
     }
 

-    Structure* structure = asCell(baseValue)->structure();
+    Structure* structure = baseValue.asCell()->structure();

 
 

-    if (structure->isUncacheableDictionary()) {
+    if (structure->isUncacheableDictionary() || structure->typeInfo().prohibitsPropertyCaching()) {

         vPC[0] = getOpcode(op_get_by_id_generic);
         return;
     }
 
     // Cache miss
         vPC[0] = getOpcode(op_get_by_id_generic);
         return;
     }
 
     // Cache miss

-    Structure* lastStructure = vPC[4].u.structure;
+    Structure* lastStructure = vPC[4].u.structure.get();

     if (structure != lastStructure) {
         // First miss: record Structure to compare against next time.
         if (!lastStructure) {
     if (structure != lastStructure) {
         // First miss: record Structure to compare against next time.
         if (!lastStructure) {

-            vPC[4] = structure;
+            vPC[4].u.structure.set(callFrame->globalData(), codeBlock->ownerExecutable(), structure);

             return;
         }
 
             return;
         }
 


@@ -1179,8 +1454,6 @@ NEVER_INLINE void Interpreter::tryCacheGetByID(CallFrame* callFrame, CodeBlock*
             vPC[5] = slot.cachedOffset();
             break;
         }
             vPC[5] = slot.cachedOffset();
             break;
         }

-
-        codeBlock->refStructures(vPC);

         return;
     }
 
         return;
     }
 


@@ -1198,8 +1471,8 @@ NEVER_INLINE void Interpreter::tryCacheGetByID(CallFrame* callFrame, CodeBlock*
         // 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()) {
         // 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->flattenDictionaryObject();
-            offset = baseObject->structure()->get(propertyName);
+            baseObject->flattenDictionaryObject(callFrame->globalData());
+            offset = baseObject->structure()->get(callFrame->globalData(), propertyName);

         }
 
         ASSERT(!baseObject->structure()->isUncacheableDictionary());
         }
 
         ASSERT(!baseObject->structure()->isUncacheableDictionary());


@@ -1218,9 +1491,7 @@ NEVER_INLINE void Interpreter::tryCacheGetByID(CallFrame* callFrame, CodeBlock*
             vPC[6] = offset;
             break;
         }
             vPC[6] = offset;
             break;
         }

-        vPC[5] = baseObject->structure();
-
-        codeBlock->refStructures(vPC);
+        vPC[5].u.structure.set(callFrame->globalData(), codeBlock->ownerExecutable(), baseObject->structure());

         return;
     }
 
         return;
     }
 


@@ -1246,22 +1517,20 @@ NEVER_INLINE void Interpreter::tryCacheGetByID(CallFrame* callFrame, CodeBlock*
         vPC[7] = offset;
         break;
     }
         vPC[7] = offset;
         break;
     }

-    vPC[4] = structure;
-    vPC[5] = structure->prototypeChain(callFrame);
+    vPC[4].u.structure.set(callFrame->globalData(), codeBlock->ownerExecutable(), structure);
+    vPC[5].u.structureChain.set(callFrame->globalData(), codeBlock->ownerExecutable(), structure->prototypeChain(callFrame));

     vPC[6] = count;
     vPC[6] = count;

-    codeBlock->refStructures(vPC);

 }
 
 }
 

-NEVER_INLINE void Interpreter::uncacheGetByID(CodeBlock* codeBlock, Instruction* vPC)
+NEVER_INLINE void Interpreter::uncacheGetByID(CodeBlock*, Instruction* vPC)

 {
 {

-    codeBlock->derefStructures(vPC);

     vPC[0] = getOpcode(op_get_by_id);
     vPC[4] = 0;
 }
 
 #endif // ENABLE(INTERPRETER)
 
     vPC[0] = getOpcode(op_get_by_id);
     vPC[4] = 0;
 }
 
 #endif // ENABLE(INTERPRETER)
 

-JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFile, CallFrame* callFrame, JSValue* exception)
+JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFile, CallFrame* callFrame)

 {
     // One-time initialization of our address tables. We have to put this code
     // here because our labels are only in scope inside this function.
 {
     // One-time initialization of our address tables. We have to put this code
     // here because our labels are only in scope inside this function.


@@ -1269,7 +1538,7 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
         #if ENABLE(COMPUTED_GOTO_INTERPRETER)
             #define LIST_OPCODE_LABEL(id, length) &&id,
                 static Opcode labels[] = { FOR_EACH_OPCODE_ID(LIST_OPCODE_LABEL) };
         #if ENABLE(COMPUTED_GOTO_INTERPRETER)
             #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)
+                for (size_t i = 0; i < WTF_ARRAY_LENGTH(labels); ++i)

                     m_opcodeTable[i] = labels[i];
             #undef LIST_OPCODE_LABEL
         #endif // ENABLE(COMPUTED_GOTO_INTERPRETER)
                     m_opcodeTable[i] = labels[i];
             #undef LIST_OPCODE_LABEL
         #endif // ENABLE(COMPUTED_GOTO_INTERPRETER)


@@ -1287,7 +1556,6 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
 #if !ENABLE(INTERPRETER)
     UNUSED_PARAM(registerFile);
     UNUSED_PARAM(callFrame);
 #if !ENABLE(INTERPRETER)
     UNUSED_PARAM(registerFile);
     UNUSED_PARAM(callFrame);

-    UNUSED_PARAM(exception);

     return JSValue();
 #else
 
     return JSValue();
 #else
 


@@ -1295,9 +1563,11 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
     JSValue exceptionValue;
     HandlerInfo* handler = 0;
 
     JSValue exceptionValue;
     HandlerInfo* handler = 0;
 

-    Instruction* vPC = callFrame->codeBlock()->instructions().begin();
+    CodeBlock* codeBlock = callFrame->codeBlock();
+    Instruction* vPC = codeBlock->instructions().begin();

     Profiler** enabledProfilerReference = Profiler::enabledProfilerReference();
     unsigned tickCount = globalData->timeoutChecker.ticksUntilNextCheck();
     Profiler** enabledProfilerReference = Profiler::enabledProfilerReference();
     unsigned tickCount = globalData->timeoutChecker.ticksUntilNextCheck();

+    JSValue functionReturnValue;

 
 #define CHECK_FOR_EXCEPTION() \
     do { \
 
 #define CHECK_FOR_EXCEPTION() \
     do { \


@@ -1327,7 +1597,7 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
 #endif
 
 #if ENABLE(COMPUTED_GOTO_INTERPRETER)
 #endif
 
 #if ENABLE(COMPUTED_GOTO_INTERPRETER)

-    #define NEXT_INSTRUCTION() SAMPLE(callFrame->codeBlock(), vPC); goto *vPC->u.opcode
+    #define NEXT_INSTRUCTION() SAMPLE(codeBlock, vPC); goto *vPC->u.opcode

 #if ENABLE(OPCODE_STATS)
     #define DEFINE_OPCODE(opcode) opcode: OpcodeStats::recordInstruction(opcode);
 #else
 #if ENABLE(OPCODE_STATS)
     #define DEFINE_OPCODE(opcode) opcode: OpcodeStats::recordInstruction(opcode);
 #else


@@ -1335,7 +1605,7 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
 #endif
     NEXT_INSTRUCTION();
 #else
 #endif
     NEXT_INSTRUCTION();
 #else

-    #define NEXT_INSTRUCTION() SAMPLE(callFrame->codeBlock(), vPC); goto interpreterLoopStart
+    #define NEXT_INSTRUCTION() SAMPLE(codeBlock, vPC); goto interpreterLoopStart

 #if ENABLE(OPCODE_STATS)
     #define DEFINE_OPCODE(opcode) case opcode: OpcodeStats::recordInstruction(opcode);
 #else
 #if ENABLE(OPCODE_STATS)
     #define DEFINE_OPCODE(opcode) case opcode: OpcodeStats::recordInstruction(opcode);
 #else


@@ -1353,7 +1623,7 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
            constructor, and puts the result in register dst.
         */
         int dst = vPC[1].u.operand;
            constructor, and puts the result in register dst.
         */
         int dst = vPC[1].u.operand;

-        callFrame->r(dst) = JSValue(constructEmptyObject(callFrame));
+        callFrame->uncheckedR(dst) = JSValue(constructEmptyObject(callFrame));

 
         vPC += OPCODE_LENGTH(op_new_object);
         NEXT_INSTRUCTION();
 
         vPC += OPCODE_LENGTH(op_new_object);
         NEXT_INSTRUCTION();


@@ -1370,11 +1640,27 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
         int firstArg = vPC[2].u.operand;
         int argCount = vPC[3].u.operand;
         ArgList args(callFrame->registers() + firstArg, argCount);
         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));
+        callFrame->uncheckedR(dst) = JSValue(constructArray(callFrame, args));

 
         vPC += OPCODE_LENGTH(op_new_array);
         NEXT_INSTRUCTION();
     }
 
         vPC += OPCODE_LENGTH(op_new_array);
         NEXT_INSTRUCTION();
     }

+    DEFINE_OPCODE(op_new_array_buffer) {
+        /* new_array_buffer dst(r) index(n) argCount(n)
+         
+         Constructs a new Array instance using the original
+         constructor, and puts the result in register dst.
+         The array be initialized with the values from constantBuffer[index]
+         */
+        int dst = vPC[1].u.operand;
+        int firstArg = vPC[2].u.operand;
+        int argCount = vPC[3].u.operand;
+        ArgList args(codeBlock->constantBuffer(firstArg), argCount);
+        callFrame->uncheckedR(dst) = JSValue(constructArray(callFrame, args));
+        
+        vPC += OPCODE_LENGTH(op_new_array);
+        NEXT_INSTRUCTION();
+    }

     DEFINE_OPCODE(op_new_regexp) {
         /* new_regexp dst(r) regExp(re)
 
     DEFINE_OPCODE(op_new_regexp) {
         /* new_regexp dst(r) regExp(re)
 


@@ -1383,8 +1669,12 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
            register dst.
         */
         int dst = vPC[1].u.operand;
            register dst.
         */
         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)));
+        RegExp* regExp = codeBlock->regexp(vPC[2].u.operand);
+        if (!regExp->isValid()) {
+            exceptionValue = createSyntaxError(callFrame, "Invalid flags supplied to RegExp constructor.");
+            goto vm_throw;
+        }
+        callFrame->uncheckedR(dst) = JSValue(new (globalData) RegExpObject(callFrame->lexicalGlobalObject(), callFrame->scopeChain()->globalObject->regExpStructure(), regExp));

 
         vPC += OPCODE_LENGTH(op_new_regexp);
         NEXT_INSTRUCTION();
 
         vPC += OPCODE_LENGTH(op_new_regexp);
         NEXT_INSTRUCTION();


@@ -1396,7 +1686,8 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
         */
         int dst = vPC[1].u.operand;
         int src = vPC[2].u.operand;
         */
         int dst = vPC[1].u.operand;
         int src = vPC[2].u.operand;

-        callFrame->r(dst) = callFrame->r(src);
+        
+        callFrame->uncheckedR(dst) = callFrame->r(src);

 
         vPC += OPCODE_LENGTH(op_mov);
         NEXT_INSTRUCTION();
 
         vPC += OPCODE_LENGTH(op_mov);
         NEXT_INSTRUCTION();


@@ -1412,11 +1703,11 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
         JSValue src1 = callFrame->r(vPC[2].u.operand).jsValue();
         JSValue src2 = callFrame->r(vPC[3].u.operand).jsValue();
         if (src1.isInt32() && src2.isInt32())
         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());
+            callFrame->uncheckedR(dst) = jsBoolean(src1.asInt32() == src2.asInt32());

         else {
             JSValue result = jsBoolean(JSValue::equalSlowCase(callFrame, src1, src2));
             CHECK_FOR_EXCEPTION();
         else {
             JSValue result = jsBoolean(JSValue::equalSlowCase(callFrame, src1, src2));
             CHECK_FOR_EXCEPTION();

-            callFrame->r(dst) = result;
+            callFrame->uncheckedR(dst) = result;

         }
 
         vPC += OPCODE_LENGTH(op_eq);
         }
 
         vPC += OPCODE_LENGTH(op_eq);


@@ -1432,12 +1723,12 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
         JSValue src = callFrame->r(vPC[2].u.operand).jsValue();
 
         if (src.isUndefinedOrNull()) {
         JSValue src = callFrame->r(vPC[2].u.operand).jsValue();
 
         if (src.isUndefinedOrNull()) {

-            callFrame->r(dst) = jsBoolean(true);
+            callFrame->uncheckedR(dst) = jsBoolean(true);

             vPC += OPCODE_LENGTH(op_eq_null);
             NEXT_INSTRUCTION();
         }
         
             vPC += OPCODE_LENGTH(op_eq_null);
             NEXT_INSTRUCTION();
         }
         

-        callFrame->r(dst) = jsBoolean(src.isCell() && src.asCell()->structure()->typeInfo().masqueradesAsUndefined());
+        callFrame->uncheckedR(dst) = jsBoolean(src.isCell() && src.asCell()->structure()->typeInfo().masqueradesAsUndefined());

         vPC += OPCODE_LENGTH(op_eq_null);
         NEXT_INSTRUCTION();
     }
         vPC += OPCODE_LENGTH(op_eq_null);
         NEXT_INSTRUCTION();
     }


@@ -1452,11 +1743,11 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
         JSValue src1 = callFrame->r(vPC[2].u.operand).jsValue();
         JSValue src2 = callFrame->r(vPC[3].u.operand).jsValue();
         if (src1.isInt32() && src2.isInt32())
         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());
+            callFrame->uncheckedR(dst) = jsBoolean(src1.asInt32() != src2.asInt32());

         else {
             JSValue result = jsBoolean(!JSValue::equalSlowCase(callFrame, src1, src2));
             CHECK_FOR_EXCEPTION();
         else {
             JSValue result = jsBoolean(!JSValue::equalSlowCase(callFrame, src1, src2));
             CHECK_FOR_EXCEPTION();

-            callFrame->r(dst) = result;
+            callFrame->uncheckedR(dst) = result;

         }
 
         vPC += OPCODE_LENGTH(op_neq);
         }
 
         vPC += OPCODE_LENGTH(op_neq);


@@ -1472,12 +1763,12 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
         JSValue src = callFrame->r(vPC[2].u.operand).jsValue();
 
         if (src.isUndefinedOrNull()) {
         JSValue src = callFrame->r(vPC[2].u.operand).jsValue();
 
         if (src.isUndefinedOrNull()) {

-            callFrame->r(dst) = jsBoolean(false);
+            callFrame->uncheckedR(dst) = jsBoolean(false);

             vPC += OPCODE_LENGTH(op_neq_null);
             NEXT_INSTRUCTION();
         }
         
             vPC += OPCODE_LENGTH(op_neq_null);
             NEXT_INSTRUCTION();
         }
         

-        callFrame->r(dst) = jsBoolean(!src.isCell() || !asCell(src)->structure()->typeInfo().masqueradesAsUndefined());
+        callFrame->uncheckedR(dst) = jsBoolean(!src.isCell() || !src.asCell()->structure()->typeInfo().masqueradesAsUndefined());

         vPC += OPCODE_LENGTH(op_neq_null);
         NEXT_INSTRUCTION();
     }
         vPC += OPCODE_LENGTH(op_neq_null);
         NEXT_INSTRUCTION();
     }


@@ -1493,7 +1784,7 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
         JSValue src2 = callFrame->r(vPC[3].u.operand).jsValue();
         bool result = JSValue::strictEqual(callFrame, src1, src2);
         CHECK_FOR_EXCEPTION();
         JSValue src2 = callFrame->r(vPC[3].u.operand).jsValue();
         bool result = JSValue::strictEqual(callFrame, src1, src2);
         CHECK_FOR_EXCEPTION();

-        callFrame->r(dst) = jsBoolean(result);
+        callFrame->uncheckedR(dst) = jsBoolean(result);

 
         vPC += OPCODE_LENGTH(op_stricteq);
         NEXT_INSTRUCTION();
 
         vPC += OPCODE_LENGTH(op_stricteq);
         NEXT_INSTRUCTION();


@@ -1510,7 +1801,7 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
         JSValue src2 = callFrame->r(vPC[3].u.operand).jsValue();
         bool result = !JSValue::strictEqual(callFrame, src1, src2);
         CHECK_FOR_EXCEPTION();
         JSValue src2 = callFrame->r(vPC[3].u.operand).jsValue();
         bool result = !JSValue::strictEqual(callFrame, src1, src2);
         CHECK_FOR_EXCEPTION();

-        callFrame->r(dst) = jsBoolean(result);
+        callFrame->uncheckedR(dst) = jsBoolean(result);

 
         vPC += OPCODE_LENGTH(op_nstricteq);
         NEXT_INSTRUCTION();
 
         vPC += OPCODE_LENGTH(op_nstricteq);
         NEXT_INSTRUCTION();


@@ -1527,7 +1818,7 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
         JSValue src2 = callFrame->r(vPC[3].u.operand).jsValue();
         JSValue result = jsBoolean(jsLess(callFrame, src1, src2));
         CHECK_FOR_EXCEPTION();
         JSValue src2 = callFrame->r(vPC[3].u.operand).jsValue();
         JSValue result = jsBoolean(jsLess(callFrame, src1, src2));
         CHECK_FOR_EXCEPTION();

-        callFrame->r(dst) = result;
+        callFrame->uncheckedR(dst) = result;

 
         vPC += OPCODE_LENGTH(op_less);
         NEXT_INSTRUCTION();
 
         vPC += OPCODE_LENGTH(op_less);
         NEXT_INSTRUCTION();


@@ -1544,7 +1835,7 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
         JSValue src2 = callFrame->r(vPC[3].u.operand).jsValue();
         JSValue result = jsBoolean(jsLessEq(callFrame, src1, src2));
         CHECK_FOR_EXCEPTION();
         JSValue src2 = callFrame->r(vPC[3].u.operand).jsValue();
         JSValue result = jsBoolean(jsLessEq(callFrame, src1, src2));
         CHECK_FOR_EXCEPTION();

-        callFrame->r(dst) = result;
+        callFrame->uncheckedR(dst) = result;

 
         vPC += OPCODE_LENGTH(op_lesseq);
         NEXT_INSTRUCTION();
 
         vPC += OPCODE_LENGTH(op_lesseq);
         NEXT_INSTRUCTION();


@@ -1558,11 +1849,11 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
         int srcDst = vPC[1].u.operand;
         JSValue v = callFrame->r(srcDst).jsValue();
         if (v.isInt32() && v.asInt32() < INT_MAX)
         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);
+            callFrame->uncheckedR(srcDst) = jsNumber(v.asInt32() + 1);

         else {
         else {

-            JSValue result = jsNumber(callFrame, v.toNumber(callFrame) + 1);
+            JSValue result = jsNumber(v.toNumber(callFrame) + 1);

             CHECK_FOR_EXCEPTION();
             CHECK_FOR_EXCEPTION();

-            callFrame->r(srcDst) = result;
+            callFrame->uncheckedR(srcDst) = result;

         }
 
         vPC += OPCODE_LENGTH(op_pre_inc);
         }
 
         vPC += OPCODE_LENGTH(op_pre_inc);


@@ -1577,11 +1868,11 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
         int srcDst = vPC[1].u.operand;
         JSValue v = callFrame->r(srcDst).jsValue();
         if (v.isInt32() && v.asInt32() > INT_MIN)
         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);
+            callFrame->uncheckedR(srcDst) = jsNumber(v.asInt32() - 1);

         else {
         else {

-            JSValue result = jsNumber(callFrame, v.toNumber(callFrame) - 1);
+            JSValue result = jsNumber(v.toNumber(callFrame) - 1);

             CHECK_FOR_EXCEPTION();
             CHECK_FOR_EXCEPTION();

-            callFrame->r(srcDst) = result;
+            callFrame->uncheckedR(srcDst) = result;

         }
 
         vPC += OPCODE_LENGTH(op_pre_dec);
         }
 
         vPC += OPCODE_LENGTH(op_pre_dec);


@@ -1598,13 +1889,13 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
         int srcDst = vPC[2].u.operand;
         JSValue v = callFrame->r(srcDst).jsValue();
         if (v.isInt32() && v.asInt32() < INT_MAX) {
         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);
-            callFrame->r(dst) = v;
+            callFrame->uncheckedR(srcDst) = jsNumber(v.asInt32() + 1);
+            callFrame->uncheckedR(dst) = v;

         } else {
             JSValue number = callFrame->r(srcDst).jsValue().toJSNumber(callFrame);
             CHECK_FOR_EXCEPTION();
         } else {
             JSValue number = callFrame->r(srcDst).jsValue().toJSNumber(callFrame);
             CHECK_FOR_EXCEPTION();

-            callFrame->r(srcDst) = jsNumber(callFrame, number.uncheckedGetNumber() + 1);
-            callFrame->r(dst) = number;
+            callFrame->uncheckedR(srcDst) = jsNumber(number.uncheckedGetNumber() + 1);
+            callFrame->uncheckedR(dst) = number;

         }
 
         vPC += OPCODE_LENGTH(op_post_inc);
         }
 
         vPC += OPCODE_LENGTH(op_post_inc);


@@ -1621,13 +1912,13 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
         int srcDst = vPC[2].u.operand;
         JSValue v = callFrame->r(srcDst).jsValue();
         if (v.isInt32() && v.asInt32() > INT_MIN) {
         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);
-            callFrame->r(dst) = v;
+            callFrame->uncheckedR(srcDst) = jsNumber(v.asInt32() - 1);
+            callFrame->uncheckedR(dst) = v;

         } else {
             JSValue number = callFrame->r(srcDst).jsValue().toJSNumber(callFrame);
             CHECK_FOR_EXCEPTION();
         } else {
             JSValue number = callFrame->r(srcDst).jsValue().toJSNumber(callFrame);
             CHECK_FOR_EXCEPTION();

-            callFrame->r(srcDst) = jsNumber(callFrame, number.uncheckedGetNumber() - 1);
-            callFrame->r(dst) = number;
+            callFrame->uncheckedR(srcDst) = jsNumber(number.uncheckedGetNumber() - 1);
+            callFrame->uncheckedR(dst) = number;

         }
 
         vPC += OPCODE_LENGTH(op_post_dec);
         }
 
         vPC += OPCODE_LENGTH(op_post_dec);


@@ -1645,11 +1936,11 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
         JSValue srcVal = callFrame->r(src).jsValue();
 
         if (LIKELY(srcVal.isNumber()))
         JSValue srcVal = callFrame->r(src).jsValue();
 
         if (LIKELY(srcVal.isNumber()))

-            callFrame->r(dst) = callFrame->r(src);
+            callFrame->uncheckedR(dst) = callFrame->r(src);

         else {
             JSValue result = srcVal.toJSNumber(callFrame);
             CHECK_FOR_EXCEPTION();
         else {
             JSValue result = srcVal.toJSNumber(callFrame);
             CHECK_FOR_EXCEPTION();

-            callFrame->r(dst) = result;
+            callFrame->uncheckedR(dst) = result;

         }
 
         vPC += OPCODE_LENGTH(op_to_jsnumber);
         }
 
         vPC += OPCODE_LENGTH(op_to_jsnumber);


@@ -1664,11 +1955,11 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
         int dst = vPC[1].u.operand;
         JSValue src = callFrame->r(vPC[2].u.operand).jsValue();
         if (src.isInt32() && (src.asInt32() & 0x7fffffff)) // non-zero and no overflow
         int dst = vPC[1].u.operand;
         JSValue src = callFrame->r(vPC[2].u.operand).jsValue();
         if (src.isInt32() && (src.asInt32() & 0x7fffffff)) // non-zero and no overflow

-            callFrame->r(dst) = jsNumber(callFrame, -src.asInt32());
+            callFrame->uncheckedR(dst) = jsNumber(-src.asInt32());

         else {
         else {

-            JSValue result = jsNumber(callFrame, -src.toNumber(callFrame));
+            JSValue result = jsNumber(-src.toNumber(callFrame));

             CHECK_FOR_EXCEPTION();
             CHECK_FOR_EXCEPTION();

-            callFrame->r(dst) = result;
+            callFrame->uncheckedR(dst) = result;

         }
 
         vPC += OPCODE_LENGTH(op_negate);
         }
 
         vPC += OPCODE_LENGTH(op_negate);


@@ -1685,11 +1976,11 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
         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
         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());
+            callFrame->uncheckedR(dst) = jsNumber(src1.asInt32() + src2.asInt32());

         else {
             JSValue result = jsAdd(callFrame, src1, src2);
             CHECK_FOR_EXCEPTION();
         else {
             JSValue result = jsAdd(callFrame, src1, src2);
             CHECK_FOR_EXCEPTION();

-            callFrame->r(dst) = result;
+            callFrame->uncheckedR(dst) = result;

         }
         vPC += OPCODE_LENGTH(op_add);
         NEXT_INSTRUCTION();
         }
         vPC += OPCODE_LENGTH(op_add);
         NEXT_INSTRUCTION();


@@ -1704,11 +1995,11 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
         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
         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());
+                callFrame->uncheckedR(dst) = jsNumber(src1.asInt32() * src2.asInt32());

         else {
         else {

-            JSValue result = jsNumber(callFrame, src1.toNumber(callFrame) * src2.toNumber(callFrame));
+            JSValue result = jsNumber(src1.toNumber(callFrame) * src2.toNumber(callFrame));

             CHECK_FOR_EXCEPTION();
             CHECK_FOR_EXCEPTION();

-            callFrame->r(dst) = result;
+            callFrame->uncheckedR(dst) = result;

         }
 
         vPC += OPCODE_LENGTH(op_mul);
         }
 
         vPC += OPCODE_LENGTH(op_mul);


@@ -1725,9 +2016,9 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
         JSValue dividend = callFrame->r(vPC[2].u.operand).jsValue();
         JSValue divisor = callFrame->r(vPC[3].u.operand).jsValue();
 
         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));
+        JSValue result = jsNumber(dividend.toNumber(callFrame) / divisor.toNumber(callFrame));

         CHECK_FOR_EXCEPTION();
         CHECK_FOR_EXCEPTION();

-        callFrame->r(dst) = result;
+        callFrame->uncheckedR(dst) = result;

 
         vPC += OPCODE_LENGTH(op_div);
         NEXT_INSTRUCTION();
 
         vPC += OPCODE_LENGTH(op_div);
         NEXT_INSTRUCTION();


@@ -1744,9 +2035,9 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
         JSValue divisor = callFrame->r(vPC[3].u.operand).jsValue();
 
         if (dividend.isInt32() && divisor.isInt32() && divisor.asInt32() != 0) {
         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());
+            JSValue result = jsNumber(dividend.asInt32() % divisor.asInt32());

             ASSERT(result);
             ASSERT(result);

-            callFrame->r(dst) = result;
+            callFrame->uncheckedR(dst) = result;

             vPC += OPCODE_LENGTH(op_mod);
             NEXT_INSTRUCTION();
         }
             vPC += OPCODE_LENGTH(op_mod);
             NEXT_INSTRUCTION();
         }


@@ -1755,9 +2046,9 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
         // order of argument evaluation is not guaranteed.
         double d1 = dividend.toNumber(callFrame);
         double d2 = divisor.toNumber(callFrame);
         // order of argument evaluation is not guaranteed.
         double d1 = dividend.toNumber(callFrame);
         double d2 = divisor.toNumber(callFrame);

-        JSValue result = jsNumber(callFrame, fmod(d1, d2));
+        JSValue result = jsNumber(fmod(d1, d2));

         CHECK_FOR_EXCEPTION();
         CHECK_FOR_EXCEPTION();

-        callFrame->r(dst) = result;
+        callFrame->uncheckedR(dst) = result;

         vPC += OPCODE_LENGTH(op_mod);
         NEXT_INSTRUCTION();
     }
         vPC += OPCODE_LENGTH(op_mod);
         NEXT_INSTRUCTION();
     }


@@ -1772,11 +2063,11 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
         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
         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());
+            callFrame->uncheckedR(dst) = jsNumber(src1.asInt32() - src2.asInt32());

         else {
         else {

-            JSValue result = jsNumber(callFrame, src1.toNumber(callFrame) - src2.toNumber(callFrame));
+            JSValue result = jsNumber(src1.toNumber(callFrame) - src2.toNumber(callFrame));

             CHECK_FOR_EXCEPTION();
             CHECK_FOR_EXCEPTION();

-            callFrame->r(dst) = result;
+            callFrame->uncheckedR(dst) = result;

         }
         vPC += OPCODE_LENGTH(op_sub);
         NEXT_INSTRUCTION();
         }
         vPC += OPCODE_LENGTH(op_sub);
         NEXT_INSTRUCTION();


@@ -1793,11 +2084,11 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
         JSValue shift = callFrame->r(vPC[3].u.operand).jsValue();
 
         if (val.isInt32() && shift.isInt32())
         JSValue shift = callFrame->r(vPC[3].u.operand).jsValue();
 
         if (val.isInt32() && shift.isInt32())

-            callFrame->r(dst) = jsNumber(callFrame, val.asInt32() << (shift.asInt32() & 0x1f));
+            callFrame->uncheckedR(dst) = jsNumber(val.asInt32() << (shift.asInt32() & 0x1f));

         else {
         else {

-            JSValue result = jsNumber(callFrame, (val.toInt32(callFrame)) << (shift.toUInt32(callFrame) & 0x1f));
+            JSValue result = jsNumber((val.toInt32(callFrame)) << (shift.toUInt32(callFrame) & 0x1f));

             CHECK_FOR_EXCEPTION();
             CHECK_FOR_EXCEPTION();

-            callFrame->r(dst) = result;
+            callFrame->uncheckedR(dst) = result;

         }
 
         vPC += OPCODE_LENGTH(op_lshift);
         }
 
         vPC += OPCODE_LENGTH(op_lshift);


@@ -1815,11 +2106,11 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
         JSValue shift = callFrame->r(vPC[3].u.operand).jsValue();
 
         if (val.isInt32() && shift.isInt32())
         JSValue shift = callFrame->r(vPC[3].u.operand).jsValue();
 
         if (val.isInt32() && shift.isInt32())

-            callFrame->r(dst) = jsNumber(callFrame, val.asInt32() >> (shift.asInt32() & 0x1f));
+            callFrame->uncheckedR(dst) = jsNumber(val.asInt32() >> (shift.asInt32() & 0x1f));

         else {
         else {

-            JSValue result = jsNumber(callFrame, (val.toInt32(callFrame)) >> (shift.toUInt32(callFrame) & 0x1f));
+            JSValue result = jsNumber((val.toInt32(callFrame)) >> (shift.toUInt32(callFrame) & 0x1f));

             CHECK_FOR_EXCEPTION();
             CHECK_FOR_EXCEPTION();

-            callFrame->r(dst) = result;
+            callFrame->uncheckedR(dst) = result;

         }
 
         vPC += OPCODE_LENGTH(op_rshift);
         }
 
         vPC += OPCODE_LENGTH(op_rshift);


@@ -1836,11 +2127,11 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
         JSValue val = callFrame->r(vPC[2].u.operand).jsValue();
         JSValue shift = callFrame->r(vPC[3].u.operand).jsValue();
         if (val.isUInt32() && shift.isInt32())
         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));
+            callFrame->uncheckedR(dst) = jsNumber(val.asInt32() >> (shift.asInt32() & 0x1f));

         else {
         else {

-            JSValue result = jsNumber(callFrame, (val.toUInt32(callFrame)) >> (shift.toUInt32(callFrame) & 0x1f));
+            JSValue result = jsNumber((val.toUInt32(callFrame)) >> (shift.toUInt32(callFrame) & 0x1f));

             CHECK_FOR_EXCEPTION();
             CHECK_FOR_EXCEPTION();

-            callFrame->r(dst) = result;
+            callFrame->uncheckedR(dst) = result;

         }
 
         vPC += OPCODE_LENGTH(op_urshift);
         }
 
         vPC += OPCODE_LENGTH(op_urshift);


@@ -1857,11 +2148,11 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
         JSValue src1 = callFrame->r(vPC[2].u.operand).jsValue();
         JSValue src2 = callFrame->r(vPC[3].u.operand).jsValue();
         if (src1.isInt32() && src2.isInt32())
         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());
+            callFrame->uncheckedR(dst) = jsNumber(src1.asInt32() & src2.asInt32());

         else {
         else {

-            JSValue result = jsNumber(callFrame, src1.toInt32(callFrame) & src2.toInt32(callFrame));
+            JSValue result = jsNumber(src1.toInt32(callFrame) & src2.toInt32(callFrame));

             CHECK_FOR_EXCEPTION();
             CHECK_FOR_EXCEPTION();

-            callFrame->r(dst) = result;
+            callFrame->uncheckedR(dst) = result;

         }
 
         vPC += OPCODE_LENGTH(op_bitand);
         }
 
         vPC += OPCODE_LENGTH(op_bitand);


@@ -1878,11 +2169,11 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
         JSValue src1 = callFrame->r(vPC[2].u.operand).jsValue();
         JSValue src2 = callFrame->r(vPC[3].u.operand).jsValue();
         if (src1.isInt32() && src2.isInt32())
         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());
+            callFrame->uncheckedR(dst) = jsNumber(src1.asInt32() ^ src2.asInt32());

         else {
         else {

-            JSValue result = jsNumber(callFrame, src1.toInt32(callFrame) ^ src2.toInt32(callFrame));
+            JSValue result = jsNumber(src1.toInt32(callFrame) ^ src2.toInt32(callFrame));

             CHECK_FOR_EXCEPTION();
             CHECK_FOR_EXCEPTION();

-            callFrame->r(dst) = result;
+            callFrame->uncheckedR(dst) = result;

         }
 
         vPC += OPCODE_LENGTH(op_bitxor);
         }
 
         vPC += OPCODE_LENGTH(op_bitxor);


@@ -1899,11 +2190,11 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
         JSValue src1 = callFrame->r(vPC[2].u.operand).jsValue();
         JSValue src2 = callFrame->r(vPC[3].u.operand).jsValue();
         if (src1.isInt32() && src2.isInt32())
         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());
+            callFrame->uncheckedR(dst) = jsNumber(src1.asInt32() | src2.asInt32());

         else {
         else {

-            JSValue result = jsNumber(callFrame, src1.toInt32(callFrame) | src2.toInt32(callFrame));
+            JSValue result = jsNumber(src1.toInt32(callFrame) | src2.toInt32(callFrame));

             CHECK_FOR_EXCEPTION();
             CHECK_FOR_EXCEPTION();

-            callFrame->r(dst) = result;
+            callFrame->uncheckedR(dst) = result;

         }
 
         vPC += OPCODE_LENGTH(op_bitor);
         }
 
         vPC += OPCODE_LENGTH(op_bitor);


@@ -1918,11 +2209,11 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
         int dst = vPC[1].u.operand;
         JSValue src = callFrame->r(vPC[2].u.operand).jsValue();
         if (src.isInt32())
         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());
+            callFrame->uncheckedR(dst) = jsNumber(~src.asInt32());

         else {
         else {

-            JSValue result = jsNumber(callFrame, ~src.toInt32(callFrame));
+            JSValue result = jsNumber(~src.toInt32(callFrame));

             CHECK_FOR_EXCEPTION();
             CHECK_FOR_EXCEPTION();

-            callFrame->r(dst) = result;
+            callFrame->uncheckedR(dst) = result;

         }
         vPC += OPCODE_LENGTH(op_bitnot);
         NEXT_INSTRUCTION();
         }
         vPC += OPCODE_LENGTH(op_bitnot);
         NEXT_INSTRUCTION();


@@ -1937,11 +2228,28 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
         int src = vPC[2].u.operand;
         JSValue result = jsBoolean(!callFrame->r(src).jsValue().toBoolean(callFrame));
         CHECK_FOR_EXCEPTION();
         int src = vPC[2].u.operand;
         JSValue result = jsBoolean(!callFrame->r(src).jsValue().toBoolean(callFrame));
         CHECK_FOR_EXCEPTION();

-        callFrame->r(dst) = result;
+        callFrame->uncheckedR(dst) = result;

 
         vPC += OPCODE_LENGTH(op_not);
         NEXT_INSTRUCTION();
     }
 
         vPC += OPCODE_LENGTH(op_not);
         NEXT_INSTRUCTION();
     }

+    DEFINE_OPCODE(op_check_has_instance) {
+        /* check_has_instance constructor(r)
+
+           Check 'constructor' is an object with the internal property
+           [HasInstance] (i.e. is a function ... *shakes head sadly at
+           JSC API*). Raises an exception if register constructor is not
+           an valid parameter for instanceof.
+        */
+        int base = vPC[1].u.operand;
+        JSValue baseVal = callFrame->r(base).jsValue();
+
+        if (isInvalidParamForInstanceOf(callFrame, baseVal, exceptionValue))
+            goto vm_throw;
+
+        vPC += OPCODE_LENGTH(op_check_has_instance);
+        NEXT_INSTRUCTION();
+    }

     DEFINE_OPCODE(op_instanceof) {
         /* instanceof dst(r) value(r) constructor(r) constructorProto(r)
 
     DEFINE_OPCODE(op_instanceof) {
         /* instanceof dst(r) value(r) constructor(r) constructorProto(r)
 


@@ -1962,12 +2270,11 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
 
         JSValue baseVal = callFrame->r(base).jsValue();
 
 
         JSValue baseVal = callFrame->r(base).jsValue();
 

-        if (isInvalidParamForInstanceOf(callFrame, callFrame->codeBlock(), vPC, baseVal, exceptionValue))
-            goto vm_throw;
+        ASSERT(!isInvalidParamForInstanceOf(callFrame, baseVal, exceptionValue));

 
         bool result = asObject(baseVal)->hasInstance(callFrame, callFrame->r(value).jsValue(), callFrame->r(baseProto).jsValue());
         CHECK_FOR_EXCEPTION();
 
         bool result = asObject(baseVal)->hasInstance(callFrame, callFrame->r(value).jsValue(), callFrame->r(baseProto).jsValue());
         CHECK_FOR_EXCEPTION();

-        callFrame->r(dst) = jsBoolean(result);
+        callFrame->uncheckedR(dst) = jsBoolean(result);

 
         vPC += OPCODE_LENGTH(op_instanceof);
         NEXT_INSTRUCTION();
 
         vPC += OPCODE_LENGTH(op_instanceof);
         NEXT_INSTRUCTION();


@@ -1980,7 +2287,7 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
         */
         int dst = vPC[1].u.operand;
         int src = vPC[2].u.operand;
         */
         int dst = vPC[1].u.operand;
         int src = vPC[2].u.operand;

-        callFrame->r(dst) = JSValue(jsTypeStringForValue(callFrame, callFrame->r(src).jsValue()));
+        callFrame->uncheckedR(dst) = JSValue(jsTypeStringForValue(callFrame, callFrame->r(src).jsValue()));

 
         vPC += OPCODE_LENGTH(op_typeof);
         NEXT_INSTRUCTION();
 
         vPC += OPCODE_LENGTH(op_typeof);
         NEXT_INSTRUCTION();


@@ -1995,7 +2302,7 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
         int dst = vPC[1].u.operand;
         int src = vPC[2].u.operand;
         JSValue v = callFrame->r(src).jsValue();
         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());
+        callFrame->uncheckedR(dst) = jsBoolean(v.isCell() ? v.asCell()->structure()->typeInfo().masqueradesAsUndefined() : v.isUndefined());

 
         vPC += OPCODE_LENGTH(op_is_undefined);
         NEXT_INSTRUCTION();
 
         vPC += OPCODE_LENGTH(op_is_undefined);
         NEXT_INSTRUCTION();


@@ -2009,7 +2316,7 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
         */
         int dst = vPC[1].u.operand;
         int src = vPC[2].u.operand;
         */
         int dst = vPC[1].u.operand;
         int src = vPC[2].u.operand;

-        callFrame->r(dst) = jsBoolean(callFrame->r(src).jsValue().isBoolean());
+        callFrame->uncheckedR(dst) = jsBoolean(callFrame->r(src).jsValue().isBoolean());

 
         vPC += OPCODE_LENGTH(op_is_boolean);
         NEXT_INSTRUCTION();
 
         vPC += OPCODE_LENGTH(op_is_boolean);
         NEXT_INSTRUCTION();


@@ -2023,7 +2330,7 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
         */
         int dst = vPC[1].u.operand;
         int src = vPC[2].u.operand;
         */
         int dst = vPC[1].u.operand;
         int src = vPC[2].u.operand;

-        callFrame->r(dst) = jsBoolean(callFrame->r(src).jsValue().isNumber());
+        callFrame->uncheckedR(dst) = jsBoolean(callFrame->r(src).jsValue().isNumber());

 
         vPC += OPCODE_LENGTH(op_is_number);
         NEXT_INSTRUCTION();
 
         vPC += OPCODE_LENGTH(op_is_number);
         NEXT_INSTRUCTION();


@@ -2037,7 +2344,7 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
         */
         int dst = vPC[1].u.operand;
         int src = vPC[2].u.operand;
         */
         int dst = vPC[1].u.operand;
         int src = vPC[2].u.operand;

-        callFrame->r(dst) = jsBoolean(callFrame->r(src).jsValue().isString());
+        callFrame->uncheckedR(dst) = jsBoolean(callFrame->r(src).jsValue().isString());

 
         vPC += OPCODE_LENGTH(op_is_string);
         NEXT_INSTRUCTION();
 
         vPC += OPCODE_LENGTH(op_is_string);
         NEXT_INSTRUCTION();


@@ -2051,7 +2358,7 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
         */
         int dst = vPC[1].u.operand;
         int src = vPC[2].u.operand;
         */
         int dst = vPC[1].u.operand;
         int src = vPC[2].u.operand;

-        callFrame->r(dst) = jsBoolean(jsIsObjectType(callFrame->r(src).jsValue()));
+        callFrame->uncheckedR(dst) = jsBoolean(jsIsObjectType(callFrame->r(src).jsValue()));

 
         vPC += OPCODE_LENGTH(op_is_object);
         NEXT_INSTRUCTION();
 
         vPC += OPCODE_LENGTH(op_is_object);
         NEXT_INSTRUCTION();


@@ -2065,7 +2372,7 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
         */
         int dst = vPC[1].u.operand;
         int src = vPC[2].u.operand;
         */
         int dst = vPC[1].u.operand;
         int src = vPC[2].u.operand;

-        callFrame->r(dst) = jsBoolean(jsIsFunctionType(callFrame->r(src).jsValue()));
+        callFrame->uncheckedR(dst) = jsBoolean(jsIsFunctionType(callFrame->r(src).jsValue()));

 
         vPC += OPCODE_LENGTH(op_is_function);
         NEXT_INSTRUCTION();
 
         vPC += OPCODE_LENGTH(op_is_function);
         NEXT_INSTRUCTION();


@@ -2084,7 +2391,7 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
         int base = vPC[3].u.operand;
 
         JSValue baseVal = callFrame->r(base).jsValue();
         int base = vPC[3].u.operand;
 
         JSValue baseVal = callFrame->r(base).jsValue();

-        if (isInvalidParamForIn(callFrame, callFrame->codeBlock(), vPC, baseVal, exceptionValue))
+        if (isInvalidParamForIn(callFrame, baseVal, exceptionValue))

             goto vm_throw;
 
         JSObject* baseObj = asObject(baseVal);
             goto vm_throw;
 
         JSObject* baseObj = asObject(baseVal);


@@ -2093,11 +2400,11 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
 
         uint32_t i;
         if (propName.getUInt32(i))
 
         uint32_t i;
         if (propName.getUInt32(i))

-            callFrame->r(dst) = jsBoolean(baseObj->hasProperty(callFrame, i));
+            callFrame->uncheckedR(dst) = jsBoolean(baseObj->hasProperty(callFrame, i));

         else {
             Identifier property(callFrame, propName.toString(callFrame));
             CHECK_FOR_EXCEPTION();
         else {
             Identifier property(callFrame, propName.toString(callFrame));
             CHECK_FOR_EXCEPTION();

-            callFrame->r(dst) = jsBoolean(baseObj->hasProperty(callFrame, property));
+            callFrame->uncheckedR(dst) = jsBoolean(baseObj->hasProperty(callFrame, property));

         }
 
         vPC += OPCODE_LENGTH(op_in);
         }
 
         vPC += OPCODE_LENGTH(op_in);


@@ -2169,11 +2476,11 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
            Gets the global var at global slot index and places it in register dst.
          */
         int dst = vPC[1].u.operand;
            Gets the global var at global slot index and places it in register dst.
          */
         int dst = vPC[1].u.operand;

-        JSGlobalObject* scope = static_cast<JSGlobalObject*>(vPC[2].u.jsCell);
+        JSGlobalObject* scope = codeBlock->globalObject();

         ASSERT(scope->isGlobalObject());
         ASSERT(scope->isGlobalObject());

-        int index = vPC[3].u.operand;
+        int index = vPC[2].u.operand;

 
 

-        callFrame->r(dst) = scope->registerAt(index);
+        callFrame->uncheckedR(dst) = scope->registerAt(index).get();

         vPC += OPCODE_LENGTH(op_get_global_var);
         NEXT_INSTRUCTION();
     }
         vPC += OPCODE_LENGTH(op_get_global_var);
         NEXT_INSTRUCTION();
     }


@@ -2182,12 +2489,12 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
          
            Puts value into global slot index.
          */
          
            Puts value into global slot index.
          */

-        JSGlobalObject* scope = static_cast<JSGlobalObject*>(vPC[1].u.jsCell);
+        JSGlobalObject* scope = codeBlock->globalObject();

         ASSERT(scope->isGlobalObject());
         ASSERT(scope->isGlobalObject());

-        int index = vPC[2].u.operand;
-        int value = vPC[3].u.operand;
+        int index = vPC[1].u.operand;
+        int value = vPC[2].u.operand;

         
         

-        scope->registerAt(index) = JSValue(callFrame->r(value).jsValue());
+        scope->registerAt(index).set(*globalData, scope, callFrame->r(value).jsValue());

         vPC += OPCODE_LENGTH(op_put_global_var);
         NEXT_INSTRUCTION();
     }
         vPC += OPCODE_LENGTH(op_put_global_var);
         NEXT_INSTRUCTION();
     }


@@ -2195,23 +2502,31 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
         /* get_scoped_var dst(r) index(n) skip(n)
 
          Loads the contents of the index-th local from the scope skip nodes from
         /* get_scoped_var dst(r) index(n) skip(n)
 
          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
+         the top of the scope chain, and places it in register dst.

          */
         int dst = vPC[1].u.operand;
         int index = vPC[2].u.operand;
          */
         int dst = vPC[1].u.operand;
         int index = vPC[2].u.operand;

-        int skip = vPC[3].u.operand + callFrame->codeBlock()->needsFullScopeChain();
+        int skip = vPC[3].u.operand;

 
         ScopeChainNode* scopeChain = callFrame->scopeChain();
         ScopeChainIterator iter = scopeChain->begin();
         ScopeChainIterator end = scopeChain->end();
         ASSERT(iter != end);
 
         ScopeChainNode* scopeChain = callFrame->scopeChain();
         ScopeChainIterator iter = scopeChain->begin();
         ScopeChainIterator end = scopeChain->end();
         ASSERT(iter != end);

+        ASSERT(codeBlock == callFrame->codeBlock());
+        bool checkTopLevel = codeBlock->codeType() == FunctionCode && codeBlock->needsFullScopeChain();
+        ASSERT(skip || !checkTopLevel);
+    if (checkTopLevel && skip--) {
+            if (callFrame->r(codeBlock->activationRegister()).jsValue())
+                ++iter;
+        }

         while (skip--) {
             ++iter;
             ASSERT(iter != end);
         }
         ASSERT((*iter)->isVariableObject());
         while (skip--) {
             ++iter;
             ASSERT(iter != end);
         }
         ASSERT((*iter)->isVariableObject());

-        JSVariableObject* scope = static_cast<JSVariableObject*>(*iter);
-        callFrame->r(dst) = scope->registerAt(index);
+        JSVariableObject* scope = static_cast<JSVariableObject*>(iter->get());
+        callFrame->uncheckedR(dst) = scope->registerAt(index).get();
+        ASSERT(callFrame->r(dst).jsValue());

         vPC += OPCODE_LENGTH(op_get_scoped_var);
         NEXT_INSTRUCTION();
     }
         vPC += OPCODE_LENGTH(op_get_scoped_var);
         NEXT_INSTRUCTION();
     }


@@ -2220,37 +2535,67 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
 
          */
         int index = vPC[1].u.operand;
 
          */
         int index = vPC[1].u.operand;

-        int skip = vPC[2].u.operand + callFrame->codeBlock()->needsFullScopeChain();
+        int skip = vPC[2].u.operand;

         int value = vPC[3].u.operand;
 
         ScopeChainNode* scopeChain = callFrame->scopeChain();
         ScopeChainIterator iter = scopeChain->begin();
         ScopeChainIterator end = scopeChain->end();
         int value = vPC[3].u.operand;
 
         ScopeChainNode* scopeChain = callFrame->scopeChain();
         ScopeChainIterator iter = scopeChain->begin();
         ScopeChainIterator end = scopeChain->end();

+        ASSERT(codeBlock == callFrame->codeBlock());

         ASSERT(iter != end);
         ASSERT(iter != end);

+        bool checkTopLevel = codeBlock->codeType() == FunctionCode && codeBlock->needsFullScopeChain();
+        ASSERT(skip || !checkTopLevel);
+    if (checkTopLevel && skip--) {
+            if (callFrame->r(codeBlock->activationRegister()).jsValue())
+                ++iter;
+        }

         while (skip--) {
             ++iter;
             ASSERT(iter != end);
         }
 
         ASSERT((*iter)->isVariableObject());
         while (skip--) {
             ++iter;
             ASSERT(iter != end);
         }
 
         ASSERT((*iter)->isVariableObject());

-        JSVariableObject* scope = static_cast<JSVariableObject*>(*iter);
-        scope->registerAt(index) = JSValue(callFrame->r(value).jsValue());
+        JSVariableObject* scope = static_cast<JSVariableObject*>(iter->get());
+        ASSERT(callFrame->r(value).jsValue());
+        scope->registerAt(index).set(*globalData, scope, callFrame->r(value).jsValue());

         vPC += OPCODE_LENGTH(op_put_scoped_var);
         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_resolve_base) {
         vPC += OPCODE_LENGTH(op_put_scoped_var);
         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_resolve_base) {

-        /* resolve_base dst(r) property(id)
+        /* resolve_base dst(r) property(id) isStrict(bool)

 
            Searches the scope chain for an object containing
            identifier property, and if one is found, writes it to
 
            Searches the scope chain for an object containing
            identifier property, and if one is found, writes it to

-           register dst. If none is found, the outermost scope (which
-           will be the global object) is stored in register dst.
+           register dst. If none is found and isStrict is false, the
+           outermost scope (which will be the global object) is
+           stored in register dst.

         */
         resolveBase(callFrame, vPC);
         */
         resolveBase(callFrame, vPC);

+        CHECK_FOR_EXCEPTION();

 
         vPC += OPCODE_LENGTH(op_resolve_base);
         NEXT_INSTRUCTION();
     }
 
         vPC += OPCODE_LENGTH(op_resolve_base);
         NEXT_INSTRUCTION();
     }

+    DEFINE_OPCODE(op_ensure_property_exists) {
+        /* ensure_property_exists base(r) property(id)
+
+           Throws an exception if property does not exist on base
+         */
+        int base = vPC[1].u.operand;
+        int property = vPC[2].u.operand;
+        Identifier& ident = codeBlock->identifier(property);
+        
+        JSValue baseVal = callFrame->r(base).jsValue();
+        JSObject* baseObject = asObject(baseVal);
+        PropertySlot slot(baseVal);
+        if (!baseObject->getPropertySlot(callFrame, ident, slot)) {
+            exceptionValue = createErrorForInvalidGlobalAssignment(callFrame, ident.ustring());
+            goto vm_throw;
+        }
+
+        vPC += OPCODE_LENGTH(op_ensure_property_exists);
+        NEXT_INSTRUCTION();
+    }

     DEFINE_OPCODE(op_resolve_with_base) {
         /* resolve_with_base baseDst(r) propDst(r) property(id)
 
     DEFINE_OPCODE(op_resolve_with_base) {
         /* resolve_with_base baseDst(r) propDst(r) property(id)
 


@@ -2279,7 +2624,6 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
         int base = vPC[2].u.operand;
         int property = vPC[3].u.operand;
 
         int base = vPC[2].u.operand;
         int property = vPC[3].u.operand;
 

-        CodeBlock* codeBlock = callFrame->codeBlock();

         Identifier& ident = codeBlock->identifier(property);
         JSValue baseValue = callFrame->r(base).jsValue();
         PropertySlot slot(baseValue);
         Identifier& ident = codeBlock->identifier(property);
         JSValue baseValue = callFrame->r(base).jsValue();
         PropertySlot slot(baseValue);


@@ -2288,7 +2632,7 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
 
         tryCacheGetByID(callFrame, codeBlock, vPC, baseValue, ident, slot);
 
 
         tryCacheGetByID(callFrame, codeBlock, vPC, baseValue, ident, slot);
 

-        callFrame->r(dst) = result;
+        callFrame->uncheckedR(dst) = result;

         vPC += OPCODE_LENGTH(op_get_by_id);
         NEXT_INSTRUCTION();
     }
         vPC += OPCODE_LENGTH(op_get_by_id);
         NEXT_INSTRUCTION();
     }


@@ -2303,8 +2647,8 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
         JSValue baseValue = callFrame->r(base).jsValue();
 
         if (LIKELY(baseValue.isCell())) {
         JSValue baseValue = callFrame->r(base).jsValue();
 
         if (LIKELY(baseValue.isCell())) {

-            JSCell* baseCell = asCell(baseValue);
-            Structure* structure = vPC[4].u.structure;
+            JSCell* baseCell = baseValue.asCell();
+            Structure* structure = vPC[4].u.structure.get();

 
             if (LIKELY(baseCell->structure() == structure)) {
                 ASSERT(baseCell->isObject());
 
             if (LIKELY(baseCell->structure() == structure)) {
                 ASSERT(baseCell->isObject());


@@ -2312,15 +2656,15 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
                 int dst = vPC[1].u.operand;
                 int offset = vPC[5].u.operand;
 
                 int dst = vPC[1].u.operand;
                 int offset = vPC[5].u.operand;
 

-                ASSERT(baseObject->get(callFrame, callFrame->codeBlock()->identifier(vPC[3].u.operand)) == baseObject->getDirectOffset(offset));
-                callFrame->r(dst) = JSValue(baseObject->getDirectOffset(offset));
+                ASSERT(baseObject->get(callFrame, codeBlock->identifier(vPC[3].u.operand)) == baseObject->getDirectOffset(offset));
+                callFrame->uncheckedR(dst) = JSValue(baseObject->getDirectOffset(offset));

 
                 vPC += OPCODE_LENGTH(op_get_by_id_self);
                 NEXT_INSTRUCTION();
             }
         }
 
 
                 vPC += OPCODE_LENGTH(op_get_by_id_self);
                 NEXT_INSTRUCTION();
             }
         }
 

-        uncacheGetByID(callFrame->codeBlock(), vPC);
+        uncacheGetByID(codeBlock, vPC);

         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_get_by_id_proto) {
         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_get_by_id_proto) {


@@ -2334,21 +2678,21 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
         JSValue baseValue = callFrame->r(base).jsValue();
 
         if (LIKELY(baseValue.isCell())) {
         JSValue baseValue = callFrame->r(base).jsValue();
 
         if (LIKELY(baseValue.isCell())) {

-            JSCell* baseCell = asCell(baseValue);
-            Structure* structure = vPC[4].u.structure;
+            JSCell* baseCell = baseValue.asCell();
+            Structure* structure = vPC[4].u.structure.get();

 
             if (LIKELY(baseCell->structure() == structure)) {
                 ASSERT(structure->prototypeForLookup(callFrame).isObject());
                 JSObject* protoObject = asObject(structure->prototypeForLookup(callFrame));
 
             if (LIKELY(baseCell->structure() == structure)) {
                 ASSERT(structure->prototypeForLookup(callFrame).isObject());
                 JSObject* protoObject = asObject(structure->prototypeForLookup(callFrame));

-                Structure* prototypeStructure = vPC[5].u.structure;
+                Structure* prototypeStructure = vPC[5].u.structure.get();

 
                 if (LIKELY(protoObject->structure() == prototypeStructure)) {
                     int dst = vPC[1].u.operand;
                     int offset = vPC[6].u.operand;
 
 
                 if (LIKELY(protoObject->structure() == prototypeStructure)) {
                     int dst = vPC[1].u.operand;
                     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));
+                    ASSERT(protoObject->get(callFrame, codeBlock->identifier(vPC[3].u.operand)) == protoObject->getDirectOffset(offset));
+                    ASSERT(baseValue.get(callFrame, codeBlock->identifier(vPC[3].u.operand)) == protoObject->getDirectOffset(offset));
+                    callFrame->uncheckedR(dst) = JSValue(protoObject->getDirectOffset(offset));

 
                     vPC += OPCODE_LENGTH(op_get_by_id_proto);
                     NEXT_INSTRUCTION();
 
                     vPC += OPCODE_LENGTH(op_get_by_id_proto);
                     NEXT_INSTRUCTION();


@@ -2356,7 +2700,7 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
             }
         }
 
             }
         }
 

-        uncacheGetByID(callFrame->codeBlock(), vPC);
+        uncacheGetByID(codeBlock, vPC);

         NEXT_INSTRUCTION();
     }
 #if USE(GCC_COMPUTED_GOTO_WORKAROUND)
         NEXT_INSTRUCTION();
     }
 #if USE(GCC_COMPUTED_GOTO_WORKAROUND)


@@ -2373,13 +2717,13 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
         JSValue baseValue = callFrame->r(base).jsValue();
         
         if (LIKELY(baseValue.isCell())) {
         JSValue baseValue = callFrame->r(base).jsValue();
         
         if (LIKELY(baseValue.isCell())) {

-            JSCell* baseCell = asCell(baseValue);
-            Structure* structure = vPC[4].u.structure;
+            JSCell* baseCell = baseValue.asCell();
+            Structure* structure = vPC[4].u.structure.get();

             
             if (LIKELY(baseCell->structure() == structure)) {
                 ASSERT(structure->prototypeForLookup(callFrame).isObject());
                 JSObject* protoObject = asObject(structure->prototypeForLookup(callFrame));
             
             if (LIKELY(baseCell->structure() == structure)) {
                 ASSERT(structure->prototypeForLookup(callFrame).isObject());
                 JSObject* protoObject = asObject(structure->prototypeForLookup(callFrame));

-                Structure* prototypeStructure = vPC[5].u.structure;
+                Structure* prototypeStructure = vPC[5].u.structure.get();

                 
                 if (LIKELY(protoObject->structure() == prototypeStructure)) {
                     int dst = vPC[1].u.operand;
                 
                 if (LIKELY(protoObject->structure() == prototypeStructure)) {
                     int dst = vPC[1].u.operand;


@@ -2390,15 +2734,15 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
                         CallType callType = getter->getCallData(callData);
                         JSValue result = call(callFrame, getter, callType, callData, asObject(baseCell), ArgList());
                         CHECK_FOR_EXCEPTION();
                         CallType callType = getter->getCallData(callData);
                         JSValue result = call(callFrame, getter, callType, callData, asObject(baseCell), ArgList());
                         CHECK_FOR_EXCEPTION();

-                        callFrame->r(dst) = result;
+                        callFrame->uncheckedR(dst) = result;

                     } else
                     } else

-                        callFrame->r(dst) = jsUndefined();
+                        callFrame->uncheckedR(dst) = jsUndefined();

                     vPC += OPCODE_LENGTH(op_get_by_id_getter_proto);
                     NEXT_INSTRUCTION();
                 }
             }
         }
                     vPC += OPCODE_LENGTH(op_get_by_id_getter_proto);
                     NEXT_INSTRUCTION();
                 }
             }
         }

-        uncacheGetByID(callFrame->codeBlock(), vPC);
+        uncacheGetByID(codeBlock, vPC);

         NEXT_INSTRUCTION();
     }
 #if USE(GCC_COMPUTED_GOTO_WORKAROUND)
         NEXT_INSTRUCTION();
     }
 #if USE(GCC_COMPUTED_GOTO_WORKAROUND)


@@ -2418,29 +2762,29 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
         JSValue baseValue = callFrame->r(base).jsValue();
         
         if (LIKELY(baseValue.isCell())) {
         JSValue baseValue = callFrame->r(base).jsValue();
         
         if (LIKELY(baseValue.isCell())) {

-            JSCell* baseCell = asCell(baseValue);
-            Structure* structure = vPC[4].u.structure;
+            JSCell* baseCell = baseValue.asCell();
+            Structure* structure = vPC[4].u.structure.get();

             
             if (LIKELY(baseCell->structure() == structure)) {
                 ASSERT(structure->prototypeForLookup(callFrame).isObject());
                 JSObject* protoObject = asObject(structure->prototypeForLookup(callFrame));
             
             if (LIKELY(baseCell->structure() == structure)) {
                 ASSERT(structure->prototypeForLookup(callFrame).isObject());
                 JSObject* protoObject = asObject(structure->prototypeForLookup(callFrame));

-                Structure* prototypeStructure = vPC[5].u.structure;
+                Structure* prototypeStructure = vPC[5].u.structure.get();

                 
                 if (LIKELY(protoObject->structure() == prototypeStructure)) {
                     int dst = vPC[1].u.operand;
                     int property = vPC[3].u.operand;
                 
                 if (LIKELY(protoObject->structure() == prototypeStructure)) {
                     int dst = vPC[1].u.operand;
                     int property = vPC[3].u.operand;

-                    Identifier& ident = callFrame->codeBlock()->identifier(property);
+                    Identifier& ident = codeBlock->identifier(property);

                     
                     PropertySlot::GetValueFunc getter = vPC[6].u.getterFunc;
                     JSValue result = getter(callFrame, protoObject, ident);
                     CHECK_FOR_EXCEPTION();
                     
                     PropertySlot::GetValueFunc getter = vPC[6].u.getterFunc;
                     JSValue result = getter(callFrame, protoObject, ident);
                     CHECK_FOR_EXCEPTION();

-                    callFrame->r(dst) = result;
+                    callFrame->uncheckedR(dst) = result;

                     vPC += OPCODE_LENGTH(op_get_by_id_custom_proto);
                     NEXT_INSTRUCTION();
                 }
             }
         }
                     vPC += OPCODE_LENGTH(op_get_by_id_custom_proto);
                     NEXT_INSTRUCTION();
                 }
             }
         }

-        uncacheGetByID(callFrame->codeBlock(), vPC);
+        uncacheGetByID(codeBlock, vPC);

         NEXT_INSTRUCTION();
     }
 #if USE(GCC_COMPUTED_GOTO_WORKAROUND)
         NEXT_INSTRUCTION();
     }
 #if USE(GCC_COMPUTED_GOTO_WORKAROUND)


@@ -2488,6 +2832,9 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
         vPC += OPCODE_LENGTH(op_get_by_id_proto_list);
         NEXT_INSTRUCTION();
     }
         vPC += OPCODE_LENGTH(op_get_by_id_proto_list);
         NEXT_INSTRUCTION();
     }

+#if USE(GCC_COMPUTED_GOTO_WORKAROUND)
+    goto *(&&skip_get_by_id_chain);
+#endif

     DEFINE_OPCODE(op_get_by_id_chain) {
         /* op_get_by_id_chain dst(r) base(r) property(id) structure(sID) structureChain(chain) count(n) offset(n)
 
     DEFINE_OPCODE(op_get_by_id_chain) {
         /* op_get_by_id_chain dst(r) base(r) property(id) structure(sID) structureChain(chain) count(n) offset(n)
 


@@ -2499,13 +2846,13 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
         JSValue baseValue = callFrame->r(base).jsValue();
 
         if (LIKELY(baseValue.isCell())) {
         JSValue baseValue = callFrame->r(base).jsValue();
 
         if (LIKELY(baseValue.isCell())) {

-            JSCell* baseCell = asCell(baseValue);
-            Structure* structure = vPC[4].u.structure;
+            JSCell* baseCell = baseValue.asCell();
+            Structure* structure = vPC[4].u.structure.get();

 
             if (LIKELY(baseCell->structure() == structure)) {
 
             if (LIKELY(baseCell->structure() == structure)) {

-                RefPtr<Structure>* it = vPC[5].u.structureChain->head();
+                WriteBarrier<Structure>* it = vPC[5].u.structureChain->head();

                 size_t count = vPC[6].u.operand;
                 size_t count = vPC[6].u.operand;

-                RefPtr<Structure>* end = it + count;
+                WriteBarrier<Structure>* end = it + count;

 
                 while (true) {
                     JSObject* baseObject = asObject(baseCell->structure()->prototypeForLookup(callFrame));
 
                 while (true) {
                     JSObject* baseObject = asObject(baseCell->structure()->prototypeForLookup(callFrame));


@@ -2517,9 +2864,9 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
                         int dst = vPC[1].u.operand;
                         int offset = vPC[7].u.operand;
 
                         int dst = vPC[1].u.operand;
                         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));
+                        ASSERT(baseObject->get(callFrame, codeBlock->identifier(vPC[3].u.operand)) == baseObject->getDirectOffset(offset));
+                        ASSERT(baseValue.get(callFrame, codeBlock->identifier(vPC[3].u.operand)) == baseObject->getDirectOffset(offset));
+                        callFrame->uncheckedR(dst) = JSValue(baseObject->getDirectOffset(offset));

 
                         vPC += OPCODE_LENGTH(op_get_by_id_chain);
                         NEXT_INSTRUCTION();
 
                         vPC += OPCODE_LENGTH(op_get_by_id_chain);
                         NEXT_INSTRUCTION();


@@ -2531,10 +2878,11 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
             }
         }
 
             }
         }
 

-        uncacheGetByID(callFrame->codeBlock(), vPC);
+        uncacheGetByID(codeBlock, vPC);

         NEXT_INSTRUCTION();
     }
 #if USE(GCC_COMPUTED_GOTO_WORKAROUND)
         NEXT_INSTRUCTION();
     }
 #if USE(GCC_COMPUTED_GOTO_WORKAROUND)

+    skip_get_by_id_chain:

     goto *(&&skip_id_getter_self);
 #endif
     DEFINE_OPCODE(op_get_by_id_getter_self) {
     goto *(&&skip_id_getter_self);
 #endif
     DEFINE_OPCODE(op_get_by_id_getter_self) {


@@ -2548,8 +2896,8 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
         JSValue baseValue = callFrame->r(base).jsValue();
         
         if (LIKELY(baseValue.isCell())) {
         JSValue baseValue = callFrame->r(base).jsValue();
         
         if (LIKELY(baseValue.isCell())) {

-            JSCell* baseCell = asCell(baseValue);
-            Structure* structure = vPC[4].u.structure;
+            JSCell* baseCell = baseValue.asCell();
+            Structure* structure = vPC[4].u.structure.get();

             
             if (LIKELY(baseCell->structure() == structure)) {
                 ASSERT(baseCell->isObject());
             
             if (LIKELY(baseCell->structure() == structure)) {
                 ASSERT(baseCell->isObject());


@@ -2563,15 +2911,15 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
                     CallType callType = getter->getCallData(callData);
                     JSValue result = call(callFrame, getter, callType, callData, baseObject, ArgList());
                     CHECK_FOR_EXCEPTION();
                     CallType callType = getter->getCallData(callData);
                     JSValue result = call(callFrame, getter, callType, callData, baseObject, ArgList());
                     CHECK_FOR_EXCEPTION();

-                    callFrame->r(dst) = result;
+                    callFrame->uncheckedR(dst) = result;

                 } else
                 } else

-                    callFrame->r(dst) = jsUndefined();
+                    callFrame->uncheckedR(dst) = jsUndefined();

 
                 vPC += OPCODE_LENGTH(op_get_by_id_getter_self);
                 NEXT_INSTRUCTION();
             }
         }
 
                 vPC += OPCODE_LENGTH(op_get_by_id_getter_self);
                 NEXT_INSTRUCTION();
             }
         }

-        uncacheGetByID(callFrame->codeBlock(), vPC);
+        uncacheGetByID(codeBlock, vPC);

         NEXT_INSTRUCTION();
     }
 #if USE(GCC_COMPUTED_GOTO_WORKAROUND)
         NEXT_INSTRUCTION();
     }
 #if USE(GCC_COMPUTED_GOTO_WORKAROUND)


@@ -2591,24 +2939,24 @@ JSValue Interpreter::privateExecute(ExecutionFlag flag, RegisterFile* registerFi
         JSValue baseValue = callFrame->r(base).jsValue();
         
         if (LIKELY(baseValue.isCell())) {
         JSValue baseValue = callFrame->r(base).jsValue();
         
         if (LIKELY(baseValue.isCell())) {

-            JSCell* baseCell = asCell(baseValue);
-            Structure* structure = vPC[4].u.structure;
+            JSCell* baseCell = baseValue.asCell();
+            Structure* structure = vPC[4].u.structure.get();

             
             if (LIKELY(baseCell->structure() == structure)) {
                 ASSERT(baseCell->isObject());
                 int dst = vPC[1].u.operand;
                 int property = vPC[3].u.operand;
             
             if (LIKELY(baseCell->structure() == structure)) {
                 ASSERT(baseCell->isObject());
                 int dst = vPC[1].u.operand;
                 int property = vPC[3].u.operand;

-                Identifier& ident = callFrame->codeBlock()->identifier(property);
+                Identifier& ident = codeBlock->identifier(property);

 
                 PropertySlot::GetValueFunc getter = vPC[5].u.getterFunc;
                 JSValue result = getter(callFrame, baseValue, ident);
                 CHECK_FOR_EXCEPTION();
 
                 PropertySlot::GetValueFunc getter = vPC[5].u.getterFunc;
                 JSValue result = getter(callFrame, baseValue, ident);
                 CHECK_FOR_EXCEPTION();

-                callFrame->r(dst) = result;
+                callFrame->uncheckedR(dst) = result;

                 vPC += OPCODE_LENGTH(op_get_by_id_custom_self);
                 NEXT_INSTRUCTION();
             }
         }
                 vPC += OPCODE_LENGTH(op_get_by_id_custom_self);
                 NEXT_INSTRUCTION();
             }
         }

-        uncacheGetByID(callFrame->codeBlock(), vPC);
+        uncacheGetByID(codeBlock, vPC);

         NEXT_INSTRUCTION();
     }
 #if USE(GCC_COMPUTED_GOTO_WORKAROUND)
         NEXT_INSTRUCTION();
     }
 #if USE(GCC_COMPUTED_GOTO_WORKAROUND)


@@ -2624,13 +2972,13 @@ skip_id_custom_self:
         int base = vPC[2].u.operand;
         int property = vPC[3].u.operand;
 
         int base = vPC[2].u.operand;
         int property = vPC[3].u.operand;
 

-        Identifier& ident = callFrame->codeBlock()->identifier(property);
+        Identifier& ident = codeBlock->identifier(property);

         JSValue baseValue = callFrame->r(base).jsValue();
         PropertySlot slot(baseValue);
         JSValue result = baseValue.get(callFrame, ident, slot);
         CHECK_FOR_EXCEPTION();
 
         JSValue baseValue = callFrame->r(base).jsValue();
         PropertySlot slot(baseValue);
         JSValue result = baseValue.get(callFrame, ident, slot);
         CHECK_FOR_EXCEPTION();
 

-        callFrame->r(dst) = result;
+        callFrame->uncheckedR(dst) = result;

         vPC += OPCODE_LENGTH(op_get_by_id_generic);
         NEXT_INSTRUCTION();
     }
         vPC += OPCODE_LENGTH(op_get_by_id_generic);
         NEXT_INSTRUCTION();
     }


@@ -2648,13 +2996,13 @@ skip_id_custom_self:
         JSValue baseValue = callFrame->r(base).jsValue();
         
         if (LIKELY(baseValue.isCell())) {
         JSValue baseValue = callFrame->r(base).jsValue();
         
         if (LIKELY(baseValue.isCell())) {

-            JSCell* baseCell = asCell(baseValue);
-            Structure* structure = vPC[4].u.structure;
+            JSCell* baseCell = baseValue.asCell();
+            Structure* structure = vPC[4].u.structure.get();

             
             if (LIKELY(baseCell->structure() == structure)) {
             
             if (LIKELY(baseCell->structure() == structure)) {

-                RefPtr<Structure>* it = vPC[5].u.structureChain->head();
+                WriteBarrier<Structure>* it = vPC[5].u.structureChain->head();

                 size_t count = vPC[6].u.operand;
                 size_t count = vPC[6].u.operand;

-                RefPtr<Structure>* end = it + count;
+                WriteBarrier<Structure>* end = it + count;

                 
                 while (true) {
                     JSObject* baseObject = asObject(baseCell->structure()->prototypeForLookup(callFrame));
                 
                 while (true) {
                     JSObject* baseObject = asObject(baseCell->structure()->prototypeForLookup(callFrame));


@@ -2671,9 +3019,9 @@ skip_id_custom_self:
                             CallType callType = getter->getCallData(callData);
                             JSValue result = call(callFrame, getter, callType, callData, baseValue, ArgList());
                             CHECK_FOR_EXCEPTION();
                             CallType callType = getter->getCallData(callData);
                             JSValue result = call(callFrame, getter, callType, callData, baseValue, ArgList());
                             CHECK_FOR_EXCEPTION();

-                            callFrame->r(dst) = result;
+                            callFrame->uncheckedR(dst) = result;

                         } else
                         } else

-                            callFrame->r(dst) = jsUndefined();
+                            callFrame->uncheckedR(dst) = jsUndefined();

                         vPC += OPCODE_LENGTH(op_get_by_id_getter_chain);
                         NEXT_INSTRUCTION();
                     }
                         vPC += OPCODE_LENGTH(op_get_by_id_getter_chain);
                         NEXT_INSTRUCTION();
                     }


@@ -2683,7 +3031,7 @@ skip_id_custom_self:
                 }
             }
         }
                 }
             }
         }

-        uncacheGetByID(callFrame->codeBlock(), vPC);
+        uncacheGetByID(codeBlock, vPC);

         NEXT_INSTRUCTION();
     }
 #if USE(GCC_COMPUTED_GOTO_WORKAROUND)
         NEXT_INSTRUCTION();
     }
 #if USE(GCC_COMPUTED_GOTO_WORKAROUND)


@@ -2703,13 +3051,13 @@ skip_id_custom_self:
         JSValue baseValue = callFrame->r(base).jsValue();
         
         if (LIKELY(baseValue.isCell())) {
         JSValue baseValue = callFrame->r(base).jsValue();
         
         if (LIKELY(baseValue.isCell())) {

-            JSCell* baseCell = asCell(baseValue);
-            Structure* structure = vPC[4].u.structure;
+            JSCell* baseCell = baseValue.asCell();
+            Structure* structure = vPC[4].u.structure.get();

             
             if (LIKELY(baseCell->structure() == structure)) {
             
             if (LIKELY(baseCell->structure() == structure)) {

-                RefPtr<Structure>* it = vPC[5].u.structureChain->head();
+                WriteBarrier<Structure>* it = vPC[5].u.structureChain->head();

                 size_t count = vPC[6].u.operand;
                 size_t count = vPC[6].u.operand;

-                RefPtr<Structure>* end = it + count;
+                WriteBarrier<Structure>* end = it + count;

                 
                 while (true) {
                     JSObject* baseObject = asObject(baseCell->structure()->prototypeForLookup(callFrame));
                 
                 while (true) {
                     JSObject* baseObject = asObject(baseCell->structure()->prototypeForLookup(callFrame));


@@ -2720,12 +3068,12 @@ skip_id_custom_self:
                     if (++it == end) {
                         int dst = vPC[1].u.operand;
                         int property = vPC[3].u.operand;
                     if (++it == end) {
                         int dst = vPC[1].u.operand;
                         int property = vPC[3].u.operand;

-                        Identifier& ident = callFrame->codeBlock()->identifier(property);
+                        Identifier& ident = codeBlock->identifier(property);

                         
                         PropertySlot::GetValueFunc getter = vPC[7].u.getterFunc;
                         JSValue result = getter(callFrame, baseObject, ident);
                         CHECK_FOR_EXCEPTION();
                         
                         PropertySlot::GetValueFunc getter = vPC[7].u.getterFunc;
                         JSValue result = getter(callFrame, baseObject, ident);
                         CHECK_FOR_EXCEPTION();

-                        callFrame->r(dst) = result;
+                        callFrame->uncheckedR(dst) = result;

                         vPC += OPCODE_LENGTH(op_get_by_id_custom_chain);
                         NEXT_INSTRUCTION();
                     }
                         vPC += OPCODE_LENGTH(op_get_by_id_custom_chain);
                         NEXT_INSTRUCTION();
                     }


@@ -2735,11 +3083,12 @@ skip_id_custom_self:
                 }
             }
         }
                 }
             }
         }

-        uncacheGetByID(callFrame->codeBlock(), vPC);
+        uncacheGetByID(codeBlock, vPC);

         NEXT_INSTRUCTION();
     }
 #if USE(GCC_COMPUTED_GOTO_WORKAROUND)
     skip_id_custom_chain:
         NEXT_INSTRUCTION();
     }
 #if USE(GCC_COMPUTED_GOTO_WORKAROUND)
     skip_id_custom_chain:

+    goto *(&&skip_get_array_length);

 #endif
     DEFINE_OPCODE(op_get_array_length) {
         /* op_get_array_length dst(r) base(r) property(id) nop(sID) nop(n) nop(n) nop(n)
 #endif
     DEFINE_OPCODE(op_get_array_length) {
         /* op_get_array_length dst(r) base(r) property(id) nop(sID) nop(n) nop(n) nop(n)


@@ -2753,14 +3102,18 @@ skip_id_custom_self:
         JSValue baseValue = callFrame->r(base).jsValue();
         if (LIKELY(isJSArray(globalData, baseValue))) {
             int dst = vPC[1].u.operand;
         JSValue baseValue = callFrame->r(base).jsValue();
         if (LIKELY(isJSArray(globalData, baseValue))) {
             int dst = vPC[1].u.operand;

-            callFrame->r(dst) = jsNumber(callFrame, asArray(baseValue)->length());
+            callFrame->uncheckedR(dst) = jsNumber(asArray(baseValue)->length());

             vPC += OPCODE_LENGTH(op_get_array_length);
             NEXT_INSTRUCTION();
         }
 
             vPC += OPCODE_LENGTH(op_get_array_length);
             NEXT_INSTRUCTION();
         }
 

-        uncacheGetByID(callFrame->codeBlock(), vPC);
+        uncacheGetByID(codeBlock, vPC);

         NEXT_INSTRUCTION();
     }
         NEXT_INSTRUCTION();
     }

+#if USE(GCC_COMPUTED_GOTO_WORKAROUND)
+    skip_get_array_length:
+    goto *(&&skip_get_string_length);
+#endif

     DEFINE_OPCODE(op_get_string_length) {
         /* op_get_string_length dst(r) base(r) property(id) nop(sID) nop(n) nop(n) nop(n)
 
     DEFINE_OPCODE(op_get_string_length) {
         /* op_get_string_length dst(r) base(r) property(id) nop(sID) nop(n) nop(n) nop(n)
 


@@ -2773,14 +3126,18 @@ skip_id_custom_self:
         JSValue baseValue = callFrame->r(base).jsValue();
         if (LIKELY(isJSString(globalData, baseValue))) {
             int dst = vPC[1].u.operand;
         JSValue baseValue = callFrame->r(base).jsValue();
         if (LIKELY(isJSString(globalData, baseValue))) {
             int dst = vPC[1].u.operand;

-            callFrame->r(dst) = jsNumber(callFrame, asString(baseValue)->length());
+            callFrame->uncheckedR(dst) = jsNumber(asString(baseValue)->length());

             vPC += OPCODE_LENGTH(op_get_string_length);
             NEXT_INSTRUCTION();
         }
 
             vPC += OPCODE_LENGTH(op_get_string_length);
             NEXT_INSTRUCTION();
         }
 

-        uncacheGetByID(callFrame->codeBlock(), vPC);
+        uncacheGetByID(codeBlock, vPC);

         NEXT_INSTRUCTION();
     }
         NEXT_INSTRUCTION();
     }

+#if USE(GCC_COMPUTED_GOTO_WORKAROUND)
+    skip_get_string_length:
+    goto *(&&skip_put_by_id);
+#endif

     DEFINE_OPCODE(op_put_by_id) {
         /* put_by_id base(r) property(id) value(r) nop(n) nop(n) nop(n) nop(n) direct(b)
 
     DEFINE_OPCODE(op_put_by_id) {
         /* put_by_id base(r) property(id) value(r) nop(n) nop(n) nop(n) nop(n) direct(b)
 


@@ -2789,7 +3146,7 @@ skip_id_custom_self:
 
            Unlike many opcodes, this one does not write any output to
            the register file.
 
            Unlike many opcodes, this one does not write any output to
            the register file.

- 
+

            The "direct" flag should only be set this put_by_id is to initialize
            an object literal.
         */
            The "direct" flag should only be set this put_by_id is to initialize
            an object literal.
         */


@@ -2799,10 +3156,9 @@ skip_id_custom_self:
         int value = vPC[3].u.operand;
         int direct = vPC[8].u.operand;
 
         int value = vPC[3].u.operand;
         int direct = vPC[8].u.operand;
 

-        CodeBlock* codeBlock = callFrame->codeBlock();

         JSValue baseValue = callFrame->r(base).jsValue();
         Identifier& ident = codeBlock->identifier(property);
         JSValue baseValue = callFrame->r(base).jsValue();
         Identifier& ident = codeBlock->identifier(property);

-        PutPropertySlot slot;
+        PutPropertySlot slot(codeBlock->isStrictMode());

         if (direct) {
             baseValue.putDirect(callFrame, ident, callFrame->r(value).jsValue(), slot);
             ASSERT(slot.base() == baseValue);
         if (direct) {
             baseValue.putDirect(callFrame, ident, callFrame->r(value).jsValue(), slot);
             ASSERT(slot.base() == baseValue);


@@ -2815,6 +3171,9 @@ skip_id_custom_self:
         vPC += OPCODE_LENGTH(op_put_by_id);
         NEXT_INSTRUCTION();
     }
         vPC += OPCODE_LENGTH(op_put_by_id);
         NEXT_INSTRUCTION();
     }

+#if USE(GCC_COMPUTED_GOTO_WORKAROUND)
+      skip_put_by_id:
+#endif

     DEFINE_OPCODE(op_put_by_id_transition) {
         /* op_put_by_id_transition base(r) property(id) value(r) oldStructure(sID) newStructure(sID) structureChain(chain) offset(n) direct(b)
          
     DEFINE_OPCODE(op_put_by_id_transition) {
         /* op_put_by_id_transition base(r) property(id) value(r) oldStructure(sID) newStructure(sID) structureChain(chain) offset(n) direct(b)
          


@@ -2830,41 +3189,41 @@ skip_id_custom_self:
         JSValue baseValue = callFrame->r(base).jsValue();
         
         if (LIKELY(baseValue.isCell())) {
         JSValue baseValue = callFrame->r(base).jsValue();
         
         if (LIKELY(baseValue.isCell())) {

-            JSCell* baseCell = asCell(baseValue);
-            Structure* oldStructure = vPC[4].u.structure;
-            Structure* newStructure = vPC[5].u.structure;
+            JSCell* baseCell = baseValue.asCell();
+            Structure* oldStructure = vPC[4].u.structure.get();
+            Structure* newStructure = vPC[5].u.structure.get();

             
             if (LIKELY(baseCell->structure() == oldStructure)) {
                 ASSERT(baseCell->isObject());
                 JSObject* baseObject = asObject(baseCell);
                 int direct = vPC[8].u.operand;
             
             if (LIKELY(baseCell->structure() == oldStructure)) {
                 ASSERT(baseCell->isObject());
                 JSObject* baseObject = asObject(baseCell);
                 int direct = vPC[8].u.operand;

-
+                

                 if (!direct) {
                 if (!direct) {

-                    RefPtr<Structure>* it = vPC[6].u.structureChain->head();
+                    WriteBarrier<Structure>* it = vPC[6].u.structureChain->head();

 
                     JSValue proto = baseObject->structure()->prototypeForLookup(callFrame);
                     while (!proto.isNull()) {
                         if (UNLIKELY(asObject(proto)->structure() != (*it).get())) {
 
                     JSValue proto = baseObject->structure()->prototypeForLookup(callFrame);
                     while (!proto.isNull()) {
                         if (UNLIKELY(asObject(proto)->structure() != (*it).get())) {

-                            uncachePutByID(callFrame->codeBlock(), vPC);
+                            uncachePutByID(codeBlock, vPC);

                             NEXT_INSTRUCTION();
                         }
                         ++it;
                         proto = asObject(proto)->structure()->prototypeForLookup(callFrame);
                     }
                 }
                             NEXT_INSTRUCTION();
                         }
                         ++it;
                         proto = asObject(proto)->structure()->prototypeForLookup(callFrame);
                     }
                 }

-                baseObject->transitionTo(newStructure);
+                baseObject->transitionTo(*globalData, newStructure);

 
                 int value = vPC[3].u.operand;
                 unsigned offset = vPC[7].u.operand;
 
                 int value = vPC[3].u.operand;
                 unsigned offset = vPC[7].u.operand;

-                ASSERT(baseObject->offsetForLocation(baseObject->getDirectLocation(callFrame->codeBlock()->identifier(vPC[2].u.operand))) == offset);
-                baseObject->putDirectOffset(offset, callFrame->r(value).jsValue());
+                ASSERT(baseObject->offsetForLocation(baseObject->getDirectLocation(*globalData, codeBlock->identifier(vPC[2].u.operand))) == offset);
+                baseObject->putDirectOffset(callFrame->globalData(), offset, callFrame->r(value).jsValue());

 
                 vPC += OPCODE_LENGTH(op_put_by_id_transition);
                 NEXT_INSTRUCTION();
             }
         }
         
 
                 vPC += OPCODE_LENGTH(op_put_by_id_transition);
                 NEXT_INSTRUCTION();
             }
         }
         

-        uncachePutByID(callFrame->codeBlock(), vPC);
+        uncachePutByID(codeBlock, vPC);

         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_put_by_id_replace) {
         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_put_by_id_replace) {


@@ -2882,8 +3241,8 @@ skip_id_custom_self:
         JSValue baseValue = callFrame->r(base).jsValue();
 
         if (LIKELY(baseValue.isCell())) {
         JSValue baseValue = callFrame->r(base).jsValue();
 
         if (LIKELY(baseValue.isCell())) {

-            JSCell* baseCell = asCell(baseValue);
-            Structure* structure = vPC[4].u.structure;
+            JSCell* baseCell = baseValue.asCell();
+            Structure* structure = vPC[4].u.structure.get();

 
             if (LIKELY(baseCell->structure() == structure)) {
                 ASSERT(baseCell->isObject());
 
             if (LIKELY(baseCell->structure() == structure)) {
                 ASSERT(baseCell->isObject());


@@ -2891,15 +3250,15 @@ skip_id_custom_self:
                 int value = vPC[3].u.operand;
                 unsigned offset = vPC[5].u.operand;
                 
                 int value = vPC[3].u.operand;
                 unsigned offset = vPC[5].u.operand;
                 

-                ASSERT(baseObject->offsetForLocation(baseObject->getDirectLocation(callFrame->codeBlock()->identifier(vPC[2].u.operand))) == offset);
-                baseObject->putDirectOffset(offset, callFrame->r(value).jsValue());
+                ASSERT(baseObject->offsetForLocation(baseObject->getDirectLocation(*globalData, codeBlock->identifier(vPC[2].u.operand))) == offset);
+                baseObject->putDirectOffset(callFrame->globalData(), offset, callFrame->r(value).jsValue());

 
                 vPC += OPCODE_LENGTH(op_put_by_id_replace);
                 NEXT_INSTRUCTION();
             }
         }
 
 
                 vPC += OPCODE_LENGTH(op_put_by_id_replace);
                 NEXT_INSTRUCTION();
             }
         }
 

-        uncachePutByID(callFrame->codeBlock(), vPC);
+        uncachePutByID(codeBlock, vPC);

         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_put_by_id_generic) {
         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_put_by_id_generic) {


@@ -2917,8 +3276,8 @@ skip_id_custom_self:
         int direct = vPC[8].u.operand;
 
         JSValue baseValue = callFrame->r(base).jsValue();
         int direct = vPC[8].u.operand;
 
         JSValue baseValue = callFrame->r(base).jsValue();

-        Identifier& ident = callFrame->codeBlock()->identifier(property);
-        PutPropertySlot slot;
+        Identifier& ident = codeBlock->identifier(property);
+        PutPropertySlot slot(codeBlock->isStrictMode());

         if (direct) {
             baseValue.putDirect(callFrame, ident, callFrame->r(value).jsValue(), slot);
             ASSERT(slot.base() == baseValue);
         if (direct) {
             baseValue.putDirect(callFrame, ident, callFrame->r(value).jsValue(), slot);
             ASSERT(slot.base() == baseValue);


@@ -2942,10 +3301,14 @@ skip_id_custom_self:
         int property = vPC[3].u.operand;
 
         JSObject* baseObj = callFrame->r(base).jsValue().toObject(callFrame);
         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));
+        Identifier& ident = codeBlock->identifier(property);
+        bool result = baseObj->deleteProperty(callFrame, ident);
+        if (!result && codeBlock->isStrictMode()) {
+            exceptionValue = createTypeError(callFrame, "Unable to delete property.");
+            goto vm_throw;
+        }

         CHECK_FOR_EXCEPTION();
         CHECK_FOR_EXCEPTION();

-        callFrame->r(dst) = result;
+        callFrame->uncheckedR(dst) = jsBoolean(result);

         vPC += OPCODE_LENGTH(op_del_by_id);
         NEXT_INSTRUCTION();
     }
         vPC += OPCODE_LENGTH(op_del_by_id);
         NEXT_INSTRUCTION();
     }


@@ -2965,17 +3328,59 @@ skip_id_custom_self:
         JSValue result;
         int offset = 0;
         if (subscript == expectedSubscript && baseValue.isCell() && (baseValue.asCell()->structure() == it->cachedStructure()) && it->getOffset(index, offset)) {
         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);
+            callFrame->uncheckedR(dst) = JSValue(asObject(baseValue)->getDirectOffset(offset));

             vPC += OPCODE_LENGTH(op_get_by_pname);
             NEXT_INSTRUCTION();
         }
             vPC += OPCODE_LENGTH(op_get_by_pname);
             NEXT_INSTRUCTION();
         }

-        Identifier propertyName(callFrame, subscript.toString(callFrame));
-        result = baseValue.get(callFrame, propertyName);
+        {
+            Identifier propertyName(callFrame, subscript.toString(callFrame));
+            result = baseValue.get(callFrame, propertyName);
+        }

         CHECK_FOR_EXCEPTION();
         CHECK_FOR_EXCEPTION();

-        callFrame->r(dst) = result;
+        callFrame->uncheckedR(dst) = result;

         vPC += OPCODE_LENGTH(op_get_by_pname);
         NEXT_INSTRUCTION();
     }
         vPC += OPCODE_LENGTH(op_get_by_pname);
         NEXT_INSTRUCTION();
     }

+    DEFINE_OPCODE(op_get_arguments_length) {
+        int dst = vPC[1].u.operand;
+        int argumentsRegister = vPC[2].u.operand;
+        int property = vPC[3].u.operand;
+        JSValue arguments = callFrame->r(argumentsRegister).jsValue();
+        if (arguments) {
+            Identifier& ident = codeBlock->identifier(property);
+            PropertySlot slot(arguments);
+            JSValue result = arguments.get(callFrame, ident, slot);
+            CHECK_FOR_EXCEPTION();
+            callFrame->uncheckedR(dst) = result;
+        } else
+            callFrame->uncheckedR(dst) = jsNumber(callFrame->argumentCount());
+
+        vPC += OPCODE_LENGTH(op_get_arguments_length);
+        NEXT_INSTRUCTION();
+    }
+    DEFINE_OPCODE(op_get_argument_by_val) {
+        int dst = vPC[1].u.operand;
+        int argumentsRegister = vPC[2].u.operand;
+        int property = vPC[3].u.operand;
+        JSValue arguments = callFrame->r(argumentsRegister).jsValue();
+        JSValue subscript = callFrame->r(property).jsValue();
+        if (!arguments && subscript.isUInt32() && subscript.asUInt32() < callFrame->argumentCount()) {
+            unsigned arg = subscript.asUInt32() + 1;
+            unsigned numParameters = callFrame->codeBlock()->m_numParameters;
+            if (arg < numParameters)
+                callFrame->uncheckedR(dst) = callFrame->r(arg - RegisterFile::CallFrameHeaderSize - numParameters);
+            else
+                callFrame->uncheckedR(dst) = callFrame->r(arg - RegisterFile::CallFrameHeaderSize - numParameters - callFrame->argumentCount() - 1);
+            vPC += OPCODE_LENGTH(op_get_argument_by_val);
+            NEXT_INSTRUCTION();
+        }
+        if (!arguments) {
+            Arguments* arguments = new (globalData) Arguments(callFrame);
+            callFrame->uncheckedR(argumentsRegister) = JSValue(arguments);
+            callFrame->uncheckedR(unmodifiedArgumentsRegister(argumentsRegister)) = JSValue(arguments);
+        }
+        // fallthrough
+    }

     DEFINE_OPCODE(op_get_by_val) {
         /* get_by_val dst(r) base(r) property(r)
 
     DEFINE_OPCODE(op_get_by_val) {
         /* get_by_val dst(r) base(r) property(r)
 


@@ -3013,7 +3418,7 @@ skip_id_custom_self:
         }
 
         CHECK_FOR_EXCEPTION();
         }
 
         CHECK_FOR_EXCEPTION();

-        callFrame->r(dst) = result;
+        callFrame->uncheckedR(dst) = result;

         vPC += OPCODE_LENGTH(op_get_by_val);
         NEXT_INSTRUCTION();
     }
         vPC += OPCODE_LENGTH(op_get_by_val);
         NEXT_INSTRUCTION();
     }


@@ -3040,7 +3445,7 @@ skip_id_custom_self:
             if (isJSArray(globalData, baseValue)) {
                 JSArray* jsArray = asArray(baseValue);
                 if (jsArray->canSetIndex(i))
             if (isJSArray(globalData, baseValue)) {
                 JSArray* jsArray = asArray(baseValue);
                 if (jsArray->canSetIndex(i))

-                    jsArray->setIndex(i, callFrame->r(value).jsValue());
+                    jsArray->setIndex(*globalData, i, callFrame->r(value).jsValue());

                 else
                     jsArray->JSArray::put(callFrame, i, callFrame->r(value).jsValue());
             } else if (isJSByteArray(globalData, baseValue) && asByteArray(baseValue)->canAccessIndex(i)) {
                 else
                     jsArray->JSArray::put(callFrame, i, callFrame->r(value).jsValue());
             } else if (isJSByteArray(globalData, baseValue) && asByteArray(baseValue)->canAccessIndex(i)) {


@@ -3058,7 +3463,7 @@ skip_id_custom_self:
         } else {
             Identifier property(callFrame, subscript.toString(callFrame));
             if (!globalData->exception) { // Don't put to an object if toString threw an exception.
         } else {
             Identifier property(callFrame, subscript.toString(callFrame));
             if (!globalData->exception) { // Don't put to an object if toString threw an exception.

-                PutPropertySlot slot;
+                PutPropertySlot slot(codeBlock->isStrictMode());

                 baseValue.put(callFrame, property, callFrame->r(value).jsValue(), slot);
             }
         }
                 baseValue.put(callFrame, property, callFrame->r(value).jsValue(), slot);
             }
         }


@@ -3082,19 +3487,22 @@ skip_id_custom_self:
         JSObject* baseObj = callFrame->r(base).jsValue().toObject(callFrame); // may throw
 
         JSValue subscript = callFrame->r(property).jsValue();
         JSObject* baseObj = callFrame->r(base).jsValue().toObject(callFrame); // may throw
 
         JSValue subscript = callFrame->r(property).jsValue();

-        JSValue result;
+        bool result;

         uint32_t i;
         if (subscript.getUInt32(i))
         uint32_t i;
         if (subscript.getUInt32(i))

-            result = jsBoolean(baseObj->deleteProperty(callFrame, i));
+            result = baseObj->deleteProperty(callFrame, i);

         else {
             CHECK_FOR_EXCEPTION();
             Identifier property(callFrame, subscript.toString(callFrame));
             CHECK_FOR_EXCEPTION();
         else {
             CHECK_FOR_EXCEPTION();
             Identifier property(callFrame, subscript.toString(callFrame));
             CHECK_FOR_EXCEPTION();

-            result = jsBoolean(baseObj->deleteProperty(callFrame, property));
+            result = baseObj->deleteProperty(callFrame, property);
+        }
+        if (!result && codeBlock->isStrictMode()) {
+            exceptionValue = createTypeError(callFrame, "Unable to delete property.");
+            goto vm_throw;

         }
         }

-

         CHECK_FOR_EXCEPTION();
         CHECK_FOR_EXCEPTION();

-        callFrame->r(dst) = result;
+        callFrame->uncheckedR(dst) = jsBoolean(result);

         vPC += OPCODE_LENGTH(op_del_by_val);
         NEXT_INSTRUCTION();
     }
         vPC += OPCODE_LENGTH(op_del_by_val);
         NEXT_INSTRUCTION();
     }


@@ -3265,10 +3673,9 @@ skip_id_custom_self:
            to ptr, using pointer equality.
          */
         int src = vPC[1].u.operand;
            to ptr, using pointer equality.
          */
         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();
         int target = vPC[3].u.operand;
         JSValue srcValue = callFrame->r(src).jsValue();

-        if (srcValue != ptr) {
+        if (srcValue != vPC[2].u.jsCell.get()) {

             vPC += target;
             NEXT_INSTRUCTION();
         }
             vPC += target;
             NEXT_INSTRUCTION();
         }


@@ -3435,12 +3842,12 @@ skip_id_custom_self:
         int defaultOffset = vPC[2].u.operand;
         JSValue scrutinee = callFrame->r(vPC[3].u.operand).jsValue();
         if (scrutinee.isInt32())
         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);
+            vPC += codeBlock->immediateSwitchJumpTable(tableIndex).offsetForValue(scrutinee.asInt32(), defaultOffset);

         else {
             double value;
             int32_t intValue;
             if (scrutinee.getNumber(value) && ((intValue = static_cast<int32_t>(value)) == value))
         else {
             double value;
             int32_t intValue;
             if (scrutinee.getNumber(value) && ((intValue = static_cast<int32_t>(value)) == value))

-                vPC += callFrame->codeBlock()->immediateSwitchJumpTable(tableIndex).offsetForValue(intValue, defaultOffset);
+                vPC += codeBlock->immediateSwitchJumpTable(tableIndex).offsetForValue(intValue, defaultOffset);

             else
                 vPC += defaultOffset;
         }
             else
                 vPC += defaultOffset;
         }


@@ -3461,11 +3868,11 @@ skip_id_custom_self:
         if (!scrutinee.isString())
             vPC += defaultOffset;
         else {
         if (!scrutinee.isString())
             vPC += defaultOffset;
         else {

-            UString::Rep* value = asString(scrutinee)->value(callFrame).rep();
+            StringImpl* value = asString(scrutinee)->value(callFrame).impl();

             if (value->length() != 1)
                 vPC += defaultOffset;
             else
             if (value->length() != 1)
                 vPC += defaultOffset;
             else

-                vPC += callFrame->codeBlock()->characterSwitchJumpTable(tableIndex).offsetForValue(value->characters()[0], defaultOffset);
+                vPC += codeBlock->characterSwitchJumpTable(tableIndex).offsetForValue(value->characters()[0], defaultOffset);

         }
         NEXT_INSTRUCTION();
     }
         }
         NEXT_INSTRUCTION();
     }


@@ -3484,7 +3891,7 @@ skip_id_custom_self:
         if (!scrutinee.isString())
             vPC += defaultOffset;
         else 
         if (!scrutinee.isString())
             vPC += defaultOffset;
         else 

-            vPC += callFrame->codeBlock()->stringSwitchJumpTable(tableIndex).offsetForValue(asString(scrutinee)->value(callFrame).rep(), defaultOffset);
+            vPC += codeBlock->stringSwitchJumpTable(tableIndex).offsetForValue(asString(scrutinee)->value(callFrame).impl(), defaultOffset);

         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_new_func) {
         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_new_func) {


@@ -3497,8 +3904,10 @@ skip_id_custom_self:
         */
         int dst = vPC[1].u.operand;
         int func = vPC[2].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()));
+        int shouldCheck = vPC[3].u.operand;
+        ASSERT(codeBlock->codeType() != FunctionCode || !codeBlock->needsFullScopeChain() || callFrame->r(codeBlock->activationRegister()).jsValue());
+        if (!shouldCheck || !callFrame->r(dst).jsValue())
+            callFrame->uncheckedR(dst) = JSValue(codeBlock->functionDecl(func)->make(callFrame, callFrame->scopeChain()));

 
         vPC += OPCODE_LENGTH(op_new_func);
         NEXT_INSTRUCTION();
 
         vPC += OPCODE_LENGTH(op_new_func);
         NEXT_INSTRUCTION();


@@ -3513,8 +3922,9 @@ skip_id_custom_self:
         */
         int dst = vPC[1].u.operand;
         int funcIndex = vPC[2].u.operand;
         */
         int dst = vPC[1].u.operand;
         int funcIndex = vPC[2].u.operand;

-
-        FunctionExecutable* function = callFrame->codeBlock()->functionExpr(funcIndex);
+        
+        ASSERT(codeBlock->codeType() != FunctionCode || !codeBlock->needsFullScopeChain() || callFrame->r(codeBlock->activationRegister()).jsValue());
+        FunctionExecutable* function = codeBlock->functionExpr(funcIndex);

         JSFunction* func = function->make(callFrame, callFrame->scopeChain());
 
         /* 
         JSFunction* func = function->make(callFrame, callFrame->scopeChain());
 
         /* 


@@ -3526,16 +3936,16 @@ skip_id_custom_self:
          */
         if (!function->name().isNull()) {
             JSStaticScopeObject* functionScopeObject = new (callFrame) JSStaticScopeObject(callFrame, function->name(), func, ReadOnly | DontDelete);
          */
         if (!function->name().isNull()) {
             JSStaticScopeObject* functionScopeObject = new (callFrame) JSStaticScopeObject(callFrame, function->name(), func, ReadOnly | DontDelete);

-            func->scope().push(functionScopeObject);
+            func->setScope(*globalData, func->scope()->push(functionScopeObject));

         }
 
         }
 

-        callFrame->r(dst) = JSValue(func);
+        callFrame->uncheckedR(dst) = JSValue(func);

 
         vPC += OPCODE_LENGTH(op_new_func_exp);
         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_call_eval) {
 
         vPC += OPCODE_LENGTH(op_new_func_exp);
         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_call_eval) {

-        /* call_eval dst(r) func(r) argCount(n) registerOffset(n)
+        /* call_eval func(r) argCount(n) registerOffset(n)

 
            Call a function named "eval" with no explicit "this" value
            (which may therefore be the eval operator). If register
 
            Call a function named "eval" with no explicit "this" value
            (which may therefore be the eval operator). If register


@@ -3546,23 +3956,23 @@ skip_id_custom_self:
            opcode). Otherwise, act exactly as the "call" opcode would.
          */
 
            opcode). Otherwise, act exactly as the "call" opcode would.
          */
 

-        int dst = vPC[1].u.operand;
-        int func = vPC[2].u.operand;
-        int argCount = vPC[3].u.operand;
-        int registerOffset = vPC[4].u.operand;
-
+        int func = vPC[1].u.operand;
+        int argCount = vPC[2].u.operand;
+        int registerOffset = vPC[3].u.operand;
+        
+        ASSERT(codeBlock->codeType() != FunctionCode || !codeBlock->needsFullScopeChain() || callFrame->r(codeBlock->activationRegister()).jsValue());

         JSValue funcVal = callFrame->r(func).jsValue();
 
         Register* newCallFrame = callFrame->registers() + registerOffset;
         Register* argv = newCallFrame - RegisterFile::CallFrameHeaderSize - argCount;
         JSValue thisValue = argv[0].jsValue();
         JSValue funcVal = callFrame->r(func).jsValue();
 
         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.get();

 
         if (thisValue == globalObject && funcVal == globalObject->evalFunction()) {
 
         if (thisValue == globalObject && funcVal == globalObject->evalFunction()) {

-            JSValue result = callEval(callFrame, registerFile, argv, argCount, registerOffset, exceptionValue);
-            if (exceptionValue)
+            JSValue result = callEval(callFrame, registerFile, argv, argCount, registerOffset);
+            if ((exceptionValue = globalData->exception))

                 goto vm_throw;
                 goto vm_throw;

-            callFrame->r(dst) = result;
+            functionReturnValue = result;

 
             vPC += OPCODE_LENGTH(op_call_eval);
             NEXT_INSTRUCTION();
 
             vPC += OPCODE_LENGTH(op_call_eval);
             NEXT_INSTRUCTION();


@@ -3573,7 +3983,7 @@ skip_id_custom_self:
         // fall through to op_call
     }
     DEFINE_OPCODE(op_call) {
         // fall through to op_call
     }
     DEFINE_OPCODE(op_call) {

-        /* call dst(r) func(r) argCount(n) registerOffset(n)
+        /* call func(r) argCount(n) registerOffset(n)

 
            Perform a function call.
            
 
            Perform a function call.
            


@@ -3583,22 +3993,26 @@ skip_id_custom_self:
            dst is where op_ret should store its result.
          */
 
            dst is where op_ret should store its result.
          */
 

-        int dst = vPC[1].u.operand;
-        int func = vPC[2].u.operand;
-        int argCount = vPC[3].u.operand;
-        int registerOffset = vPC[4].u.operand;
+        int func = vPC[1].u.operand;
+        int argCount = vPC[2].u.operand;
+        int registerOffset = vPC[3].u.operand;

 
         JSValue v = callFrame->r(func).jsValue();
 
         CallData callData;
 
         JSValue v = callFrame->r(func).jsValue();
 
         CallData callData;

-        CallType callType = v.getCallData(callData);
+        CallType callType = getCallData(v, callData);

 
         if (callType == CallTypeJS) {
             ScopeChainNode* callDataScopeChain = callData.js.scopeChain;
 
         if (callType == CallTypeJS) {
             ScopeChainNode* callDataScopeChain = callData.js.scopeChain;

-            CodeBlock* newCodeBlock = &callData.js.functionExecutable->bytecode(callFrame, callDataScopeChain);

 
 

-            CallFrame* previousCallFrame = callFrame;
+            JSObject* error = callData.js.functionExecutable->compileForCall(callFrame, callDataScopeChain);
+            if (UNLIKELY(!!error)) {
+                exceptionValue = error;
+                goto vm_throw;
+            }

 
 

+            CallFrame* previousCallFrame = callFrame;
+            CodeBlock* newCodeBlock = &callData.js.functionExecutable->generatedBytecodeForCall();

             callFrame = slideRegisterWindowForCall(newCodeBlock, registerFile, callFrame, registerOffset, argCount);
             if (UNLIKELY(!callFrame)) {
                 callFrame = previousCallFrame;
             callFrame = slideRegisterWindowForCall(newCodeBlock, registerFile, callFrame, registerOffset, argCount);
             if (UNLIKELY(!callFrame)) {
                 callFrame = previousCallFrame;


@@ -3606,7 +4020,9 @@ skip_id_custom_self:
                 goto vm_throw;
             }
 
                 goto vm_throw;
             }
 

-            callFrame->init(newCodeBlock, vPC + 5, callDataScopeChain, previousCallFrame, dst, argCount, asFunction(v));
+            callFrame->init(newCodeBlock, vPC + OPCODE_LENGTH(op_call), callDataScopeChain, previousCallFrame, argCount, asFunction(v));
+            codeBlock = newCodeBlock;
+            ASSERT(codeBlock == callFrame->codeBlock());

             vPC = newCodeBlock->instructions().begin();
 
 #if ENABLE(OPCODE_STATS)
             vPC = newCodeBlock->instructions().begin();
 
 #if ENABLE(OPCODE_STATS)


@@ -3619,24 +4035,21 @@ skip_id_custom_self:
         if (callType == CallTypeHost) {
             ScopeChainNode* scopeChain = callFrame->scopeChain();
             CallFrame* newCallFrame = CallFrame::create(callFrame->registers() + registerOffset);
         if (callType == CallTypeHost) {
             ScopeChainNode* scopeChain = callFrame->scopeChain();
             CallFrame* newCallFrame = CallFrame::create(callFrame->registers() + registerOffset);

-            newCallFrame->init(0, vPC + 5, scopeChain, callFrame, dst, argCount, 0);
-
-            Register* thisRegister = newCallFrame->registers() - RegisterFile::CallFrameHeaderSize - argCount;
-            ArgList args(thisRegister + 1, argCount - 1);
+            if (!registerFile->grow(newCallFrame->registers())) {
+                exceptionValue = createStackOverflowError(callFrame);
+                goto vm_throw;
+            }

 
 

-            // FIXME: All host methods should be calling toThisObject, but this is not presently the case.
-            JSValue thisValue = thisRegister->jsValue();
-            if (thisValue == jsNull())
-                thisValue = callFrame->globalThisValue();
+            newCallFrame->init(0, vPC + OPCODE_LENGTH(op_call), scopeChain, callFrame, argCount, asObject(v));

 
             JSValue returnValue;
             {
                 SamplingTool::HostCallRecord callRecord(m_sampler.get());
 
             JSValue returnValue;
             {
                 SamplingTool::HostCallRecord callRecord(m_sampler.get());

-                returnValue = callData.native.function(newCallFrame, asObject(v), thisValue, args);
+                returnValue = JSValue::decode(callData.native.function(newCallFrame));

             }
             CHECK_FOR_EXCEPTION();
 
             }
             CHECK_FOR_EXCEPTION();
 

-            callFrame->r(dst) = returnValue;
+            functionReturnValue = returnValue;

 
             vPC += OPCODE_LENGTH(op_call);
             NEXT_INSTRUCTION();
 
             vPC += OPCODE_LENGTH(op_call);
             NEXT_INSTRUCTION();


@@ -3644,7 +4057,7 @@ skip_id_custom_self:
 
         ASSERT(callType == CallTypeNone);
 
 
         ASSERT(callType == CallTypeNone);
 

-        exceptionValue = createNotAFunctionError(callFrame, v, vPC - callFrame->codeBlock()->instructions().begin(), callFrame->codeBlock());
+        exceptionValue = createNotAFunctionError(callFrame, v);

         goto vm_throw;
     }
     DEFINE_OPCODE(op_load_varargs) {
         goto vm_throw;
     }
     DEFINE_OPCODE(op_load_varargs) {


@@ -3654,7 +4067,7 @@ skip_id_custom_self:
         JSValue arguments = callFrame->r(argsOffset).jsValue();
         uint32_t argCount = 0;
         if (!arguments) {
         JSValue arguments = callFrame->r(argsOffset).jsValue();
         uint32_t argCount = 0;
         if (!arguments) {

-            argCount = (uint32_t)(callFrame->argumentCount()) - 1;
+            argCount = (uint32_t)(callFrame->argumentCount());

             argCount = min<uint32_t>(argCount, Arguments::MaxArguments);
             int32_t sizeDelta = argsOffset + argCount + RegisterFile::CallFrameHeaderSize;
             Register* newEnd = callFrame->registers() + sizeDelta;
             argCount = min<uint32_t>(argCount, Arguments::MaxArguments);
             int32_t sizeDelta = argsOffset + argCount + RegisterFile::CallFrameHeaderSize;
             Register* newEnd = callFrame->registers() + sizeDelta;


@@ -3662,24 +4075,24 @@ skip_id_custom_self:
                 exceptionValue = createStackOverflowError(callFrame);
                 goto vm_throw;
             }
                 exceptionValue = createStackOverflowError(callFrame);
                 goto vm_throw;
             }

-            ASSERT(!callFrame->callee()->isHostFunction());
-            uint32_t expectedParams = callFrame->callee()->jsExecutable()->parameterCount();
-            uint32_t inplaceArgs = min(argCount, expectedParams);
-            uint32_t i = 0;
+            ASSERT(!asFunction(callFrame->callee())->isHostFunction());
+            int32_t expectedParams = asFunction(callFrame->callee())->jsExecutable()->parameterCount();
+            int32_t inplaceArgs = min(static_cast<int32_t>(argCount), expectedParams);
+            int32_t i = 0;

             Register* argStore = callFrame->registers() + argsOffset;
 
             // First step is to copy the "expected" parameters from their normal location relative to the callframe
             for (; i < inplaceArgs; i++)
                 argStore[i] = callFrame->registers()[i - RegisterFile::CallFrameHeaderSize - expectedParams];
             // Then we copy any additional arguments that may be further up the stack ('-1' to account for 'this')
             Register* argStore = callFrame->registers() + argsOffset;
 
             // First step is to copy the "expected" parameters from their normal location relative to the callframe
             for (; i < inplaceArgs; i++)
                 argStore[i] = callFrame->registers()[i - RegisterFile::CallFrameHeaderSize - expectedParams];
             // Then we copy any additional arguments that may be further up the stack ('-1' to account for 'this')

-            for (; i < argCount; i++)
-                argStore[i] = callFrame->registers()[i - RegisterFile::CallFrameHeaderSize - expectedParams - argCount - 1];
+            for (; i < static_cast<int32_t>(argCount); i++)
+                argStore[i] = callFrame->registers()[i - RegisterFile::CallFrameHeaderSize - expectedParams - static_cast<int32_t>(argCount) - 1];

         } else if (!arguments.isUndefinedOrNull()) {
             if (!arguments.isObject()) {
         } else if (!arguments.isUndefinedOrNull()) {
             if (!arguments.isObject()) {

-                exceptionValue = createInvalidParamError(callFrame, "Function.prototype.apply", arguments, vPC - callFrame->codeBlock()->instructions().begin(), callFrame->codeBlock());
+                exceptionValue = createInvalidParamError(callFrame, "Function.prototype.apply", arguments);

                 goto vm_throw;
             }
                 goto vm_throw;
             }

-            if (asObject(arguments)->classInfo() == &Arguments::info) {
+            if (asObject(arguments)->classInfo() == &Arguments::s_info) {

                 Arguments* args = asArguments(arguments);
                 argCount = args->numProvidedArguments(callFrame);
                 argCount = min<uint32_t>(argCount, Arguments::MaxArguments);
                 Arguments* args = asArguments(arguments);
                 argCount = args->numProvidedArguments(callFrame);
                 argCount = min<uint32_t>(argCount, Arguments::MaxArguments);


@@ -3701,7 +4114,7 @@ skip_id_custom_self:
                     goto vm_throw;
                 }
                 array->copyToRegisters(callFrame, callFrame->registers() + argsOffset, argCount);
                     goto vm_throw;
                 }
                 array->copyToRegisters(callFrame, callFrame->registers() + argsOffset, argCount);

-            } else if (asObject(arguments)->inherits(&JSArray::info)) {
+            } else if (asObject(arguments)->inherits(&JSArray::s_info)) {

                 JSObject* argObject = asObject(arguments);
                 argCount = argObject->get(callFrame, callFrame->propertyNames().length).toUInt32(callFrame);
                 argCount = min<uint32_t>(argCount, Arguments::MaxArguments);
                 JSObject* argObject = asObject(arguments);
                 argCount = argObject->get(callFrame, callFrame->propertyNames().length).toUInt32(callFrame);
                 argCount = min<uint32_t>(argCount, Arguments::MaxArguments);


@@ -3717,17 +4130,17 @@ skip_id_custom_self:
                     CHECK_FOR_EXCEPTION();
                 }
             } else {
                     CHECK_FOR_EXCEPTION();
                 }
             } else {

-                exceptionValue = createInvalidParamError(callFrame, "Function.prototype.apply", arguments, vPC - callFrame->codeBlock()->instructions().begin(), callFrame->codeBlock());
+                exceptionValue = createInvalidParamError(callFrame, "Function.prototype.apply", arguments);

                 goto vm_throw;
             }
         }
         CHECK_FOR_EXCEPTION();
                 goto vm_throw;
             }
         }
         CHECK_FOR_EXCEPTION();

-        callFrame->r(argCountDst) = Register::withInt(argCount + 1);
+        callFrame->uncheckedR(argCountDst) = Register::withInt(argCount + 1);

         vPC += OPCODE_LENGTH(op_load_varargs);
         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_call_varargs) {
         vPC += OPCODE_LENGTH(op_load_varargs);
         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_call_varargs) {

-        /* call_varargs dst(r) func(r) argCountReg(r) baseRegisterOffset(n)
+        /* call_varargs func(r) argCountReg(r) baseRegisterOffset(n)

          
          Perform a function call with a dynamic set of arguments.
          
          
          Perform a function call with a dynamic set of arguments.
          


@@ -3738,31 +4151,37 @@ skip_id_custom_self:
          dst is where op_ret should store its result.
          */
         
          dst is where op_ret should store its result.
          */
         

-        int dst = vPC[1].u.operand;
-        int func = vPC[2].u.operand;
-        int argCountReg = vPC[3].u.operand;
-        int registerOffset = vPC[4].u.operand;
+        int func = vPC[1].u.operand;
+        int argCountReg = vPC[2].u.operand;
+        int registerOffset = vPC[3].u.operand;

         
         JSValue v = callFrame->r(func).jsValue();
         int argCount = callFrame->r(argCountReg).i();
         registerOffset += argCount;
         CallData callData;
         
         JSValue v = callFrame->r(func).jsValue();
         int argCount = callFrame->r(argCountReg).i();
         registerOffset += argCount;
         CallData callData;

-        CallType callType = v.getCallData(callData);
+        CallType callType = getCallData(v, callData);

         
         if (callType == CallTypeJS) {
             ScopeChainNode* callDataScopeChain = callData.js.scopeChain;
         
         if (callType == CallTypeJS) {
             ScopeChainNode* callDataScopeChain = callData.js.scopeChain;

-            CodeBlock* newCodeBlock = &callData.js.functionExecutable->bytecode(callFrame, callDataScopeChain);
-            
+
+            JSObject* error = callData.js.functionExecutable->compileForCall(callFrame, callDataScopeChain);
+            if (UNLIKELY(!!error)) {
+                exceptionValue = error;
+                goto vm_throw;
+            }
+

             CallFrame* previousCallFrame = callFrame;
             CallFrame* previousCallFrame = callFrame;

-            
+            CodeBlock* newCodeBlock = &callData.js.functionExecutable->generatedBytecodeForCall();

             callFrame = slideRegisterWindowForCall(newCodeBlock, registerFile, callFrame, registerOffset, argCount);
             if (UNLIKELY(!callFrame)) {
                 callFrame = previousCallFrame;
                 exceptionValue = createStackOverflowError(callFrame);
                 goto vm_throw;
             }
             callFrame = slideRegisterWindowForCall(newCodeBlock, registerFile, callFrame, registerOffset, argCount);
             if (UNLIKELY(!callFrame)) {
                 callFrame = previousCallFrame;
                 exceptionValue = createStackOverflowError(callFrame);
                 goto vm_throw;
             }

-            
-            callFrame->init(newCodeBlock, vPC + 5, callDataScopeChain, previousCallFrame, dst, argCount, asFunction(v));
+
+            callFrame->init(newCodeBlock, vPC + OPCODE_LENGTH(op_call_varargs), callDataScopeChain, previousCallFrame, argCount, asFunction(v));
+            codeBlock = newCodeBlock;
+            ASSERT(codeBlock == callFrame->codeBlock());

             vPC = newCodeBlock->instructions().begin();
             
 #if ENABLE(OPCODE_STATS)
             vPC = newCodeBlock->instructions().begin();
             
 #if ENABLE(OPCODE_STATS)


@@ -3775,24 +4194,20 @@ skip_id_custom_self:
         if (callType == CallTypeHost) {
             ScopeChainNode* scopeChain = callFrame->scopeChain();
             CallFrame* newCallFrame = CallFrame::create(callFrame->registers() + registerOffset);
         if (callType == CallTypeHost) {
             ScopeChainNode* scopeChain = callFrame->scopeChain();
             CallFrame* newCallFrame = CallFrame::create(callFrame->registers() + registerOffset);

-            newCallFrame->init(0, vPC + 5, scopeChain, callFrame, dst, argCount, 0);
-            
-            Register* thisRegister = newCallFrame->registers() - RegisterFile::CallFrameHeaderSize - argCount;
-            ArgList args(thisRegister + 1, argCount - 1);
-            
-            // FIXME: All host methods should be calling toThisObject, but this is not presently the case.
-            JSValue thisValue = thisRegister->jsValue();
-            if (thisValue == jsNull())
-                thisValue = callFrame->globalThisValue();
+            if (!registerFile->grow(newCallFrame->registers())) {
+                exceptionValue = createStackOverflowError(callFrame);
+                goto vm_throw;
+            }
+            newCallFrame->init(0, vPC + OPCODE_LENGTH(op_call_varargs), scopeChain, callFrame, argCount, asObject(v));

             
             JSValue returnValue;
             {
                 SamplingTool::HostCallRecord callRecord(m_sampler.get());
             
             JSValue returnValue;
             {
                 SamplingTool::HostCallRecord callRecord(m_sampler.get());

-                returnValue = callData.native.function(newCallFrame, asObject(v), thisValue, args);
+                returnValue = JSValue::decode(callData.native.function(newCallFrame));

             }
             CHECK_FOR_EXCEPTION();
             
             }
             CHECK_FOR_EXCEPTION();
             

-            callFrame->r(dst) = returnValue;
+            functionReturnValue = returnValue;

             
             vPC += OPCODE_LENGTH(op_call_varargs);
             NEXT_INSTRUCTION();
             
             vPC += OPCODE_LENGTH(op_call_varargs);
             NEXT_INSTRUCTION();


@@ -3800,52 +4215,99 @@ skip_id_custom_self:
         
         ASSERT(callType == CallTypeNone);
         
         
         ASSERT(callType == CallTypeNone);
         

-        exceptionValue = createNotAFunctionError(callFrame, v, vPC - callFrame->codeBlock()->instructions().begin(), callFrame->codeBlock());
+        exceptionValue = createNotAFunctionError(callFrame, v);

         goto vm_throw;
     }
     DEFINE_OPCODE(op_tear_off_activation) {
         goto vm_throw;
     }
     DEFINE_OPCODE(op_tear_off_activation) {

-        /* tear_off_activation activation(r)
+        /* tear_off_activation activation(r) arguments(r)

 
 

-           Copy all locals and parameters to new memory allocated on
-           the heap, and make the passed activation use this memory
-           in the future when looking up entries in the symbol table.
-           If there is an 'arguments' object, then it will also use
-           this memory for storing the named parameters, but not any
-           extra arguments.
+           Copy locals and named parameters from the register file to the heap.
+           Point the bindings in 'activation' and 'arguments' to this new backing
+           store. (Note that 'arguments' may not have been created. If created,
+           'arguments' already holds a copy of any extra / unnamed parameters.)

 
 

-           This opcode should only be used immediately before op_ret.
+           This opcode appears before op_ret in functions that require full scope chains.

         */
 
         */
 

-        int src = vPC[1].u.operand;
-        ASSERT(callFrame->codeBlock()->needsFullScopeChain());
+        int activation = vPC[1].u.operand;
+        int arguments = vPC[2].u.operand;
+        ASSERT(codeBlock->needsFullScopeChain());
+        JSValue activationValue = callFrame->r(activation).jsValue();
+        if (activationValue) {
+            asActivation(activationValue)->copyRegisters(*globalData);

 
 

-        asActivation(callFrame->r(src).jsValue())->copyRegisters(callFrame->optionalCalleeArguments());
+            if (JSValue argumentsValue = callFrame->r(unmodifiedArgumentsRegister(arguments)).jsValue()) {
+                if (!codeBlock->isStrictMode())
+                    asArguments(argumentsValue)->setActivation(*globalData, asActivation(activationValue));
+            }
+        } else if (JSValue argumentsValue = callFrame->r(unmodifiedArgumentsRegister(arguments)).jsValue()) {
+            if (!codeBlock->isStrictMode())
+                asArguments(argumentsValue)->copyRegisters(*globalData);
+        }

 
         vPC += OPCODE_LENGTH(op_tear_off_activation);
         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_tear_off_arguments) {
 
         vPC += OPCODE_LENGTH(op_tear_off_activation);
         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_tear_off_arguments) {

-        /* tear_off_arguments
+        /* tear_off_arguments arguments(r)

 
 

-           Copy all arguments to new memory allocated on the heap,
-           and make the 'arguments' object use this memory in the
-           future when looking up named parameters, but not any
-           extra arguments. If an activation object exists for the
-           current function context, then the tear_off_activation
-           opcode should be used instead.
+           Copy named parameters from the register file to the heap. Point the
+           bindings in 'arguments' to this new backing store. (Note that
+           'arguments' may not have been created. If created, 'arguments' already
+           holds a copy of any extra / unnamed parameters.)

 
 

-           This opcode should only be used immediately before op_ret.
+           This opcode appears before op_ret in functions that don't require full
+           scope chains, but do use 'arguments'.

         */
 
         */
 

-        ASSERT(callFrame->codeBlock()->usesArguments() && !callFrame->codeBlock()->needsFullScopeChain());
+        int src1 = vPC[1].u.operand;
+        ASSERT(!codeBlock->needsFullScopeChain() && codeBlock->ownerExecutable()->usesArguments());

 
 

-        if (callFrame->optionalCalleeArguments())
-            callFrame->optionalCalleeArguments()->copyRegisters();
+        if (JSValue arguments = callFrame->r(unmodifiedArgumentsRegister(src1)).jsValue())
+            asArguments(arguments)->copyRegisters(*globalData);

 
         vPC += OPCODE_LENGTH(op_tear_off_arguments);
         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_ret) {
 
         vPC += OPCODE_LENGTH(op_tear_off_arguments);
         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_ret) {

+        /* ret result(r)
+           
+           Return register result as the return value of the current
+           function call, writing it into functionReturnValue.
+           In addition, unwind one call frame and restore the scope
+           chain, code block instruction pointer and register base
+           to those of the calling function.
+        */
+
+        int result = vPC[1].u.operand;
+
+        JSValue returnValue = callFrame->r(result).jsValue();
+
+        vPC = callFrame->returnVPC();
+        callFrame = callFrame->callerFrame();
+        
+        if (callFrame->hasHostCallFrameFlag())
+            return returnValue;
+
+        functionReturnValue = returnValue;
+        codeBlock = callFrame->codeBlock();
+        ASSERT(codeBlock == callFrame->codeBlock());
+
+        NEXT_INSTRUCTION();
+    }
+    DEFINE_OPCODE(op_call_put_result) {
+        /* op_call_put_result result(r)
+           
+           Move call result from functionReturnValue to caller's
+           expected return value register.
+        */
+
+        callFrame->uncheckedR(vPC[1].u.operand) = functionReturnValue;
+
+        vPC += OPCODE_LENGTH(op_call_put_result);
+        NEXT_INSTRUCTION();
+    }
+    DEFINE_OPCODE(op_ret_object_or_this) {

         /* ret result(r)
            
            Return register result as the return value of the current
         /* ret result(r)
            
            Return register result as the return value of the current


@@ -3857,67 +4319,93 @@ skip_id_custom_self:
 
         int result = vPC[1].u.operand;
 
 
         int result = vPC[1].u.operand;
 

-        if (callFrame->codeBlock()->needsFullScopeChain())
-            callFrame->scopeChain()->deref();
-

         JSValue returnValue = callFrame->r(result).jsValue();
 
         JSValue returnValue = callFrame->r(result).jsValue();
 

+        if (UNLIKELY(!returnValue.isObject()))
+            returnValue = callFrame->r(vPC[2].u.operand).jsValue();
+

         vPC = callFrame->returnVPC();
         vPC = callFrame->returnVPC();

-        int dst = callFrame->returnValueRegister();

         callFrame = callFrame->callerFrame();
         callFrame = callFrame->callerFrame();

-        
+

         if (callFrame->hasHostCallFrameFlag())
             return returnValue;
 
         if (callFrame->hasHostCallFrameFlag())
             return returnValue;
 

-        callFrame->r(dst) = returnValue;
+        functionReturnValue = returnValue;
+        codeBlock = callFrame->codeBlock();
+        ASSERT(codeBlock == callFrame->codeBlock());

 
         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_enter) {
         /* enter
 
 
         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_enter) {
         /* enter
 

-           Initializes local variables to undefined and fills constant
-           registers with their values. If the code block requires an
-           activation, enter_with_activation should be used instead.
+           Initializes local variables to undefined. If the code block requires
+           an activation, enter_with_activation is used instead.

 
 

-           This opcode should only be used at the beginning of a code
-           block.
+           This opcode appears only at the beginning of a code block.

         */
 
         size_t i = 0;
         */
 
         size_t i = 0;

-        CodeBlock* codeBlock = callFrame->codeBlock();
-        

         for (size_t count = codeBlock->m_numVars; i < count; ++i)
         for (size_t count = codeBlock->m_numVars; i < count; ++i)

-            callFrame->r(i) = jsUndefined();
+            callFrame->uncheckedR(i) = jsUndefined();

 
         vPC += OPCODE_LENGTH(op_enter);
         NEXT_INSTRUCTION();
     }
 
         vPC += OPCODE_LENGTH(op_enter);
         NEXT_INSTRUCTION();
     }

-    DEFINE_OPCODE(op_enter_with_activation) {
-        /* enter_with_activation dst(r)
+    DEFINE_OPCODE(op_create_activation) {
+        /* create_activation dst(r)

 
 

-           Initializes local variables to undefined, fills constant
-           registers with their values, creates an activation object,
-           and places the new activation both in dst and at the top
-           of the scope chain. If the code block does not require an
-           activation, enter should be used instead.
+           If the activation object for this callframe has not yet been created,
+           this creates it and writes it back to dst.
+        */
+
+        int activationReg = vPC[1].u.operand;
+        if (!callFrame->r(activationReg).jsValue()) {
+            JSActivation* activation = new (globalData) JSActivation(callFrame, static_cast<FunctionExecutable*>(codeBlock->ownerExecutable()));
+            callFrame->r(activationReg) = JSValue(activation);
+            callFrame->setScopeChain(callFrame->scopeChain()->push(activation));
+        }
+        vPC += OPCODE_LENGTH(op_create_activation);
+        NEXT_INSTRUCTION();
+    }
+    DEFINE_OPCODE(op_get_callee) {
+        /* op_get_callee callee(r)
+
+           Move callee into a register.
+        */
+
+        callFrame->uncheckedR(vPC[1].u.operand) = JSValue(callFrame->callee());
+
+        vPC += OPCODE_LENGTH(op_get_callee);
+        NEXT_INSTRUCTION();
+    }
+    DEFINE_OPCODE(op_create_this) {
+        /* op_create_this this(r) proto(r)
+
+           Allocate an object as 'this', fr use in construction.

 
            This opcode should only be used at the beginning of a code
            block.
         */
 
 
            This opcode should only be used at the beginning of a code
            block.
         */
 

-        size_t i = 0;
-        CodeBlock* codeBlock = callFrame->codeBlock();
+        int thisRegister = vPC[1].u.operand;
+        int protoRegister = vPC[2].u.operand;

 
 

-        for (size_t count = codeBlock->m_numVars; i < count; ++i)
-            callFrame->r(i) = jsUndefined();
+        JSFunction* constructor = asFunction(callFrame->callee());
+#if !ASSERT_DISABLED
+        ConstructData constructData;
+        ASSERT(constructor->getConstructData(constructData) == ConstructTypeJS);
+#endif

 
 

-        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));
+        Structure* structure;
+        JSValue proto = callFrame->r(protoRegister).jsValue();
+        if (proto.isObject())
+            structure = asObject(proto)->inheritorID(callFrame->globalData());
+        else
+            structure = constructor->scope()->globalObject->emptyObjectStructure();
+        callFrame->uncheckedR(thisRegister) = constructEmptyObject(callFrame, structure);

 
 

-        vPC += OPCODE_LENGTH(op_enter_with_activation);
+        vPC += OPCODE_LENGTH(op_create_this);

         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_convert_this) {
         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_convert_this) {


@@ -3935,43 +4423,63 @@ skip_id_custom_self:
         int thisRegister = vPC[1].u.operand;
         JSValue thisVal = callFrame->r(thisRegister).jsValue();
         if (thisVal.needsThisConversion())
         int thisRegister = vPC[1].u.operand;
         JSValue thisVal = callFrame->r(thisRegister).jsValue();
         if (thisVal.needsThisConversion())

-            callFrame->r(thisRegister) = JSValue(thisVal.toThisObject(callFrame));
+            callFrame->uncheckedR(thisRegister) = JSValue(thisVal.toThisObject(callFrame));

 
         vPC += OPCODE_LENGTH(op_convert_this);
         NEXT_INSTRUCTION();
     }
 
         vPC += OPCODE_LENGTH(op_convert_this);
         NEXT_INSTRUCTION();
     }

-    DEFINE_OPCODE(op_init_arguments) {
-        /* create_arguments
+    DEFINE_OPCODE(op_convert_this_strict) {
+        /* convert_this_strict this(r)
+         
+         Takes the value in the 'this' register, and converts it to
+         its "this" form if (and only if) "this" is an object with a
+         custom this conversion
+         
+         This opcode should only be used at the beginning of a code
+         block.
+         */
+        
+        int thisRegister = vPC[1].u.operand;
+        JSValue thisVal = callFrame->r(thisRegister).jsValue();
+        if (thisVal.isObject() && thisVal.needsThisConversion())
+            callFrame->uncheckedR(thisRegister) = JSValue(thisVal.toStrictThisObject(callFrame));
+        
+        vPC += OPCODE_LENGTH(op_convert_this_strict);
+        NEXT_INSTRUCTION();
+    }
+    DEFINE_OPCODE(op_init_lazy_reg) {
+        /* init_lazy_reg dst(r)

 
 

-           Initialises the arguments object reference to null to ensure
-           we can correctly detect that we need to create it later (or
-           avoid creating it altogether).
+           Initialises dst(r) to JSValue().

 
 

-           This opcode should only be used at the beginning of a code
-           block.
+           This opcode appears only at the beginning of a code block.

          */
          */

-        callFrame->r(RegisterFile::ArgumentsRegister) = JSValue();
-        vPC += OPCODE_LENGTH(op_init_arguments);
+        int dst = vPC[1].u.operand;
+
+        callFrame->uncheckedR(dst) = JSValue();
+        vPC += OPCODE_LENGTH(op_init_lazy_reg);

         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_create_arguments) {
         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_create_arguments) {

-        /* create_arguments
+        /* create_arguments dst(r)

 
            Creates the 'arguments' object and places it in both the
            'arguments' call frame slot and the local 'arguments'
            register, if it has not already been initialised.
          */
         
 
            Creates the 'arguments' object and places it in both the
            'arguments' call frame slot and the local 'arguments'
            register, if it has not already been initialised.
          */
         

-         if (!callFrame->r(RegisterFile::ArgumentsRegister).jsValue()) {
-             Arguments* arguments = new (globalData) Arguments(callFrame);
-             callFrame->setCalleeArguments(arguments);
-             callFrame->r(RegisterFile::ArgumentsRegister) = JSValue(arguments);
-         }
+        int dst = vPC[1].u.operand;
+
+        if (!callFrame->r(dst).jsValue()) {
+            Arguments* arguments = new (globalData) Arguments(callFrame);
+            callFrame->uncheckedR(dst) = JSValue(arguments);
+            callFrame->uncheckedR(unmodifiedArgumentsRegister(dst)) = JSValue(arguments);
+        }

         vPC += OPCODE_LENGTH(op_create_arguments);
         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_construct) {
         vPC += OPCODE_LENGTH(op_create_arguments);
         NEXT_INSTRUCTION();
     }
     DEFINE_OPCODE(op_construct) {

-        /* construct dst(r) func(r) argCount(n) registerOffset(n) proto(r) thisRegister(r)
+        /* construct func(r) argCount(n) registerOffset(n) proto(r) thisRegister(r)

 
            Invoke register "func" as a constructor. For JS
            functions, the calling convention is exactly as for the
 
            Invoke register "func" as a constructor. For JS
            functions, the calling convention is exactly as for the


@@ -3985,34 +4493,26 @@ skip_id_custom_self:
            caching of this lookup.
         */
 
            caching of this lookup.
         */
 

-        int dst = vPC[1].u.operand;
-        int func = vPC[2].u.operand;
-        int argCount = vPC[3].u.operand;
-        int registerOffset = vPC[4].u.operand;
-        int proto = vPC[5].u.operand;
-        int thisRegister = vPC[6].u.operand;
+        int func = vPC[1].u.operand;
+        int argCount = vPC[2].u.operand;
+        int registerOffset = vPC[3].u.operand;

 
         JSValue v = callFrame->r(func).jsValue();
 
         ConstructData constructData;
 
         JSValue v = callFrame->r(func).jsValue();
 
         ConstructData constructData;

-        ConstructType constructType = v.getConstructData(constructData);
+        ConstructType constructType = getConstructData(v, constructData);

 
         if (constructType == ConstructTypeJS) {
             ScopeChainNode* callDataScopeChain = constructData.js.scopeChain;
 
         if (constructType == ConstructTypeJS) {
             ScopeChainNode* callDataScopeChain = constructData.js.scopeChain;

-            CodeBlock* newCodeBlock = &constructData.js.functionExecutable->bytecode(callFrame, callDataScopeChain);
-
-            Structure* structure;
-            JSValue prototype = callFrame->r(proto).jsValue();
-            if (prototype.isObject())
-                structure = asObject(prototype)->inheritorID();
-            else
-                structure = callDataScopeChain->globalObject->emptyObjectStructure();
-            JSObject* newObject = new (globalData) JSObject(structure);

 
 

-            callFrame->r(thisRegister) = JSValue(newObject); // "this" value
+            JSObject* error = constructData.js.functionExecutable->compileForConstruct(callFrame, callDataScopeChain);
+            if (UNLIKELY(!!error)) {
+                exceptionValue = error;
+                goto vm_throw;
+            }

 
             CallFrame* previousCallFrame = callFrame;
 
             CallFrame* previousCallFrame = callFrame;

-
+            CodeBlock* newCodeBlock = &constructData.js.functionExecutable->generatedBytecodeForConstruct();

             callFrame = slideRegisterWindowForCall(newCodeBlock, registerFile, callFrame, registerOffset, argCount);
             if (UNLIKELY(!callFrame)) {
                 callFrame = previousCallFrame;
             callFrame = slideRegisterWindowForCall(newCodeBlock, registerFile, callFrame, registerOffset, argCount);
             if (UNLIKELY(!callFrame)) {
                 callFrame = previousCallFrame;


@@ -4020,7 +4520,8 @@ skip_id_custom_self:
                 goto vm_throw;
             }
 
                 goto vm_throw;
             }
 

-            callFrame->init(newCodeBlock, vPC + 7, callDataScopeChain, previousCallFrame, dst, argCount, asFunction(v));
+            callFrame->init(newCodeBlock, vPC + OPCODE_LENGTH(op_construct), callDataScopeChain, previousCallFrame, argCount, asFunction(v));
+            codeBlock = newCodeBlock;

             vPC = newCodeBlock->instructions().begin();
 #if ENABLE(OPCODE_STATS)
             OpcodeStats::resetLastInstruction();
             vPC = newCodeBlock->instructions().begin();
 #if ENABLE(OPCODE_STATS)
             OpcodeStats::resetLastInstruction();


@@ -4030,19 +4531,21 @@ skip_id_custom_self:
         }
 
         if (constructType == ConstructTypeHost) {
         }
 
         if (constructType == ConstructTypeHost) {

-            ArgList args(callFrame->registers() + thisRegister + 1, argCount - 1);
-

             ScopeChainNode* scopeChain = callFrame->scopeChain();
             CallFrame* newCallFrame = CallFrame::create(callFrame->registers() + registerOffset);
             ScopeChainNode* scopeChain = callFrame->scopeChain();
             CallFrame* newCallFrame = CallFrame::create(callFrame->registers() + registerOffset);

-            newCallFrame->init(0, vPC + 7, scopeChain, callFrame, dst, argCount, 0);
+            if (!registerFile->grow(newCallFrame->registers())) {
+                exceptionValue = createStackOverflowError(callFrame);
+                goto vm_throw;
+            }
+            newCallFrame->init(0, vPC + OPCODE_LENGTH(op_construct), scopeChain, callFrame, argCount, asObject(v));

 
             JSValue returnValue;
             {
                 SamplingTool::HostCallRecord callRecord(m_sampler.get());
 
             JSValue returnValue;
             {
                 SamplingTool::HostCallRecord callRecord(m_sampler.get());

-                returnValue = constructData.native.function(newCallFrame, asObject(v), args);
+                returnValue = JSValue::decode(constructData.native.function(newCallFrame));

             }
             CHECK_FOR_EXCEPTION();
             }
             CHECK_FOR_EXCEPTION();

-            callFrame->r(dst) = JSValue(returnValue);
+            functionReturnValue = returnValue;

 
             vPC += OPCODE_LENGTH(op_construct);
             NEXT_INSTRUCTION();
 
             vPC += OPCODE_LENGTH(op_construct);
             NEXT_INSTRUCTION();


@@ -4050,34 +4553,23 @@ skip_id_custom_self:
 
         ASSERT(constructType == ConstructTypeNone);
 
 
         ASSERT(constructType == ConstructTypeNone);
 

-        exceptionValue = createNotAConstructorError(callFrame, v, vPC - callFrame->codeBlock()->instructions().begin(), callFrame->codeBlock());
+        exceptionValue = createNotAConstructorError(callFrame, v);

         goto vm_throw;
     }
         goto vm_throw;
     }

-    DEFINE_OPCODE(op_construct_verify) {
-        /* construct_verify dst(r) override(r)
+    DEFINE_OPCODE(op_strcat) {
+        /* strcat dst(r) src(r) count(n)

 
 

-           Verifies that register dst holds an object. If not, moves
-           the object in register override to register dst.
+           Construct a new String instance using the original
+           constructor, and puts the result in register dst.
+           The string will be the result of concatenating count
+           strings with values taken from registers starting at
+           register src.

         */
         */

-
-        int dst = vPC[1].u.operand;
-        if (LIKELY(callFrame->r(dst).jsValue().isObject())) {
-            vPC += OPCODE_LENGTH(op_construct_verify);
-            NEXT_INSTRUCTION();
-        }
-
-        int override = vPC[2].u.operand;
-        callFrame->r(dst) = callFrame->r(override);
-
-        vPC += OPCODE_LENGTH(op_construct_verify);
-        NEXT_INSTRUCTION();
-    }
-    DEFINE_OPCODE(op_strcat) {

         int dst = vPC[1].u.operand;
         int src = vPC[2].u.operand;
         int count = vPC[3].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);
+        callFrame->uncheckedR(dst) = concatenateStrings(callFrame, &callFrame->registers()[src], count);

         CHECK_FOR_EXCEPTION();
         vPC += OPCODE_LENGTH(op_strcat);
 
         CHECK_FOR_EXCEPTION();
         vPC += OPCODE_LENGTH(op_strcat);
 


@@ -4087,7 +4579,7 @@ skip_id_custom_self:
         int dst = vPC[1].u.operand;
         int src = vPC[2].u.operand;
 
         int dst = vPC[1].u.operand;
         int src = vPC[2].u.operand;
 

-        callFrame->r(dst) = callFrame->r(src).jsValue().toPrimitive(callFrame);
+        callFrame->uncheckedR(dst) = callFrame->r(src).jsValue().toPrimitive(callFrame);

         vPC += OPCODE_LENGTH(op_to_primitive);
 
         NEXT_INSTRUCTION();
         vPC += OPCODE_LENGTH(op_to_primitive);
 
         NEXT_INSTRUCTION();


@@ -4104,7 +4596,7 @@ skip_id_custom_self:
         JSObject* o = v.toObject(callFrame);
         CHECK_FOR_EXCEPTION();
 
         JSObject* o = v.toObject(callFrame);
         CHECK_FOR_EXCEPTION();
 

-        callFrame->r(scope) = JSValue(o);
+        callFrame->uncheckedR(scope) = JSValue(o);

         callFrame->setScopeChain(callFrame->scopeChain()->push(o));
 
         vPC += OPCODE_LENGTH(op_push_scope);
         callFrame->setScopeChain(callFrame->scopeChain()->push(o));
 
         vPC += OPCODE_LENGTH(op_push_scope);


@@ -4145,10 +4637,10 @@ skip_id_custom_self:
         if (!jsPropertyNameIterator || jsPropertyNameIterator->cachedPrototypeChain() != structure->prototypeChain(callFrame))
             jsPropertyNameIterator = JSPropertyNameIterator::create(callFrame, o);
 
         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());
+        callFrame->uncheckedR(dst) = jsPropertyNameIterator;
+        callFrame->uncheckedR(base) = JSValue(o);
+        callFrame->uncheckedR(i) = Register::withInt(0);
+        callFrame->uncheckedR(size) = Register::withInt(jsPropertyNameIterator->size());

         vPC += OPCODE_LENGTH(op_get_pnames);
         NEXT_INSTRUCTION();
     }
         vPC += OPCODE_LENGTH(op_get_pnames);
         NEXT_INSTRUCTION();
     }


@@ -4170,10 +4662,11 @@ skip_id_custom_self:
         JSPropertyNameIterator* it = callFrame->r(iter).propertyNameIterator();
         while (callFrame->r(i).i() != callFrame->r(size).i()) {
             JSValue key = it->get(callFrame, asObject(callFrame->r(base).jsValue()), callFrame->r(i).i());
         JSPropertyNameIterator* it = callFrame->r(iter).propertyNameIterator();
         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);
+            CHECK_FOR_EXCEPTION();
+            callFrame->uncheckedR(i) = Register::withInt(callFrame->r(i).i() + 1);

             if (key) {
                 CHECK_FOR_TIMEOUT();
             if (key) {
                 CHECK_FOR_TIMEOUT();

-                callFrame->r(dst) = key;
+                callFrame->uncheckedR(dst) = key;

                 vPC += target;
                 NEXT_INSTRUCTION();
             }
                 vPC += target;
                 NEXT_INSTRUCTION();
             }


@@ -4229,7 +4722,7 @@ skip_id_custom_self:
         ASSERT(exceptionValue);
         ASSERT(!globalData->exception);
         int ex = vPC[1].u.operand;
         ASSERT(exceptionValue);
         ASSERT(!globalData->exception);
         int ex = vPC[1].u.operand;

-        callFrame->r(ex) = exceptionValue;
+        callFrame->uncheckedR(ex) = exceptionValue;

         exceptionValue = JSValue();
 
         vPC += OPCODE_LENGTH(op_catch);
         exceptionValue = JSValue();
 
         vPC += OPCODE_LENGTH(op_catch);


@@ -4249,32 +4742,24 @@ skip_id_custom_self:
         int ex = vPC[1].u.operand;
         exceptionValue = callFrame->r(ex).jsValue();
 
         int ex = vPC[1].u.operand;
         exceptionValue = callFrame->r(ex).jsValue();
 

-        handler = throwException(callFrame, exceptionValue, vPC - callFrame->codeBlock()->instructions().begin(), true);
-        if (!handler) {
-            *exception = exceptionValue;
-            return jsNull();
-        }
+        handler = throwException(callFrame, exceptionValue, vPC - codeBlock->instructions().begin());
+        if (!handler)
+            return throwError(callFrame, exceptionValue);

 
 

-        vPC = callFrame->codeBlock()->instructions().begin() + handler->target;
+        codeBlock = callFrame->codeBlock();
+        vPC = codeBlock->instructions().begin() + handler->target;

         NEXT_INSTRUCTION();
     }
         NEXT_INSTRUCTION();
     }

-    DEFINE_OPCODE(op_new_error) {
-        /* new_error dst(r) type(n) message(k)
+    DEFINE_OPCODE(op_throw_reference_error) {
+        /* op_throw_reference_error message(k)

 
 

-           Constructs a new Error instance using the original
-           constructor, using immediate number n as the type and
-           constant message as the message string. The result is
-           written to register dst.
+           Constructs a new reference Error instance using the
+           original constructor, using constant message as the
+           message string. The result is thrown.

         */
         */

-        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 += OPCODE_LENGTH(op_new_error);
-        NEXT_INSTRUCTION();
+        UString message = callFrame->r(vPC[1].u.operand).jsValue().toString(callFrame);
+        exceptionValue = JSValue(createReferenceError(callFrame, message));
+        goto vm_throw;

     }
     DEFINE_OPCODE(op_end) {
         /* end result(r)
     }
     DEFINE_OPCODE(op_end) {
         /* end result(r)


@@ -4283,11 +4768,6 @@ skip_id_custom_self:
            program. Return control to the calling native code.
         */
 
            program. Return control to the calling native code.
         */
 

-        if (callFrame->codeBlock()->needsFullScopeChain()) {
-            ScopeChainNode* scopeChain = callFrame->scopeChain();
-            ASSERT(scopeChain->refCount > 1);
-            scopeChain->deref();
-        }

         int result = vPC[1].u.operand;
         return callFrame->r(result).jsValue();
     }
         int result = vPC[1].u.operand;
         return callFrame->r(result).jsValue();
     }


@@ -4308,7 +4788,7 @@ skip_id_custom_self:
 
         ASSERT(callFrame->r(base).jsValue().isObject());
         JSObject* baseObj = asObject(callFrame->r(base).jsValue());
 
         ASSERT(callFrame->r(base).jsValue().isObject());
         JSObject* baseObj = asObject(callFrame->r(base).jsValue());

-        Identifier& ident = callFrame->codeBlock()->identifier(property);
+        Identifier& ident = codeBlock->identifier(property);

         ASSERT(callFrame->r(function).jsValue().isObject());
         baseObj->defineGetter(callFrame, ident, asObject(callFrame->r(function).jsValue()));
 
         ASSERT(callFrame->r(function).jsValue().isObject());
         baseObj->defineGetter(callFrame, ident, asObject(callFrame->r(function).jsValue()));
 


@@ -4332,7 +4812,7 @@ skip_id_custom_self:
 
         ASSERT(callFrame->r(base).jsValue().isObject());
         JSObject* baseObj = asObject(callFrame->r(base).jsValue());
 
         ASSERT(callFrame->r(base).jsValue().isObject());
         JSObject* baseObj = asObject(callFrame->r(base).jsValue());

-        Identifier& ident = callFrame->codeBlock()->identifier(property);
+        Identifier& ident = codeBlock->identifier(property);

         ASSERT(callFrame->r(function).jsValue().isObject());
         baseObj->defineSetter(callFrame, ident, asObject(callFrame->r(function).jsValue()), 0);
 
         ASSERT(callFrame->r(function).jsValue().isObject());
         baseObj->defineSetter(callFrame, ident, asObject(callFrame->r(function).jsValue()), 0);
 


@@ -4417,13 +4897,16 @@ skip_id_custom_self:
             // cannot fathom if we don't assign to the exceptionValue before branching)
             exceptionValue = createInterruptedExecutionException(globalData);
         }
             // cannot fathom if we don't assign to the exceptionValue before branching)
             exceptionValue = createInterruptedExecutionException(globalData);
         }

-        handler = throwException(callFrame, exceptionValue, vPC - callFrame->codeBlock()->instructions().begin(), false);
+        JSGlobalObject* globalObject = callFrame->lexicalGlobalObject();
+        handler = throwException(callFrame, exceptionValue, vPC - codeBlock->instructions().begin());

         if (!handler) {
         if (!handler) {

-            *exception = exceptionValue;
-            return jsNull();
+            // Can't use the callframe at this point as the scopechain, etc have
+            // been released.
+            return throwError(globalObject->globalExec(), exceptionValue);

         }
 
         }
 

-        vPC = callFrame->codeBlock()->instructions().begin() + handler->target;
+        codeBlock = callFrame->codeBlock();
+        vPC = codeBlock->instructions().begin() + handler->target;

         NEXT_INSTRUCTION();
     }
     }
         NEXT_INSTRUCTION();
     }
     }


@@ -4446,27 +4929,22 @@ JSValue Interpreter::retrieveArguments(CallFrame* callFrame, JSFunction* functio
     CodeBlock* codeBlock = functionCallFrame->codeBlock();
     if (codeBlock->usesArguments()) {
         ASSERT(codeBlock->codeType() == FunctionCode);
     CodeBlock* codeBlock = functionCallFrame->codeBlock();
     if (codeBlock->usesArguments()) {
         ASSERT(codeBlock->codeType() == FunctionCode);

-        SymbolTable& symbolTable = *codeBlock->symbolTable();
-        int argumentsIndex = symbolTable.get(functionCallFrame->propertyNames().arguments.ustring().rep()).getIndex();
-        if (!functionCallFrame->r(argumentsIndex).jsValue()) {
-            Arguments* arguments = new (callFrame) Arguments(functionCallFrame);
-            functionCallFrame->setCalleeArguments(arguments);
-            functionCallFrame->r(RegisterFile::ArgumentsRegister) = JSValue(arguments);
-        }
-        return functionCallFrame->r(argumentsIndex).jsValue();
-    }
-
-    Arguments* arguments = functionCallFrame->optionalCalleeArguments();
-    if (!arguments) {
-        arguments = new (functionCallFrame) Arguments(functionCallFrame);
-        arguments->copyRegisters();
-        callFrame->setCalleeArguments(arguments);
-    }
-
+        int argumentsRegister = codeBlock->argumentsRegister();
+        int realArgumentsRegister = unmodifiedArgumentsRegister(argumentsRegister);
+        if (JSValue arguments = functionCallFrame->uncheckedR(argumentsRegister).jsValue())
+            return arguments;
+        JSValue arguments = JSValue(new (callFrame) Arguments(functionCallFrame));
+        functionCallFrame->r(argumentsRegister) = arguments;
+        functionCallFrame->r(realArgumentsRegister) = arguments;
+        return arguments;
+    }
+
+    Arguments* arguments = new (functionCallFrame) Arguments(functionCallFrame);
+    arguments->copyRegisters(functionCallFrame->globalData());

     return arguments;
 }
 
     return arguments;
 }
 

-JSValue Interpreter::retrieveCaller(CallFrame* callFrame, InternalFunction* function) const
+JSValue Interpreter::retrieveCaller(CallFrame* callFrame, JSFunction* function) const

 {
     CallFrame* functionCallFrame = findFunctionCallFrame(callFrame, function);
     if (!functionCallFrame)
 {
     CallFrame* functionCallFrame = findFunctionCallFrame(callFrame, function);
     if (!functionCallFrame)


@@ -4499,21 +4977,21 @@ void Interpreter::retrieveLastCaller(CallFrame* callFrame, int& lineNumber, intp
     unsigned bytecodeOffset = 0;
 #if ENABLE(INTERPRETER)
     if (!callerFrame->globalData().canUseJIT())
     unsigned bytecodeOffset = 0;
 #if ENABLE(INTERPRETER)
     if (!callerFrame->globalData().canUseJIT())

-        bytecodeOffset = bytecodeOffsetForPC(callerFrame, callerCodeBlock, callFrame->returnVPC());
+        bytecodeOffset = callerCodeBlock->bytecodeOffset(callFrame->returnVPC());

 #if ENABLE(JIT)
     else
 #if ENABLE(JIT)
     else

-        bytecodeOffset = bytecodeOffsetForPC(callerFrame, callerCodeBlock, callFrame->returnPC());
+        bytecodeOffset = callerCodeBlock->bytecodeOffset(callFrame->returnPC());

 #endif
 #else
 #endif
 #else

-    bytecodeOffset = bytecodeOffsetForPC(callerFrame, callerCodeBlock, callFrame->returnPC());
+    bytecodeOffset = callerCodeBlock->bytecodeOffset(callFrame->returnPC());

 #endif
 #endif

-    lineNumber = callerCodeBlock->lineNumberForBytecodeOffset(callerFrame, bytecodeOffset - 1);
+    lineNumber = callerCodeBlock->lineNumberForBytecodeOffset(bytecodeOffset - 1);

     sourceID = callerCodeBlock->ownerExecutable()->sourceID();
     sourceURL = callerCodeBlock->ownerExecutable()->sourceURL();
     function = callerFrame->callee();
 }
 
     sourceID = callerCodeBlock->ownerExecutable()->sourceID();
     sourceURL = callerCodeBlock->ownerExecutable()->sourceURL();
     function = callerFrame->callee();
 }
 

-CallFrame* Interpreter::findFunctionCallFrame(CallFrame* callFrame, InternalFunction* function)
+CallFrame* Interpreter::findFunctionCallFrame(CallFrame* callFrame, JSFunction* function)

 {
     for (CallFrame* candidate = callFrame; candidate; candidate = candidate->callerFrame()->removeHostCallFrameFlag()) {
         if (candidate->callee() == function)
 {
     for (CallFrame* candidate = callFrame; candidate; candidate = candidate->callerFrame()->removeHostCallFrameFlag()) {
         if (candidate->callee() == function)