JavaScriptCore-7601.1.46.3.tar.gz

[apple/javascriptcore.git] / bytecompiler / NodesCodegen.cpp

diff --git a/bytecompiler/NodesCodegen.cpp b/bytecompiler/NodesCodegen.cpp
index c91e6160d232a13fb81ce7b543ce42d180c9a430..cfd3ef1ff6e80752d980d690147c4507507e5f61 100644 (file)
--- a/bytecompiler/NodesCodegen.cpp
+++ b/bytecompiler/NodesCodegen.cpp
@@ -1,7 +1,7 @@
 /*
 *  Copyright (C) 1999-2002 Harri Porten (porten@kde.org)
 *  Copyright (C) 2001 Peter Kelly (pmk@post.com)
 /*
 *  Copyright (C) 1999-2002 Harri Porten (porten@kde.org)
 *  Copyright (C) 2001 Peter Kelly (pmk@post.com)

-*  Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2012, 2013 Apple Inc. All rights reserved.
+*  Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2012, 2013, 2015 Apple Inc. All rights reserved.

 *  Copyright (C) 2007 Cameron Zwarich (cwzwarich@uwaterloo.ca)
 *  Copyright (C) 2007 Maks Orlovich
 *  Copyright (C) 2007 Eric Seidel <eric@webkit.org>
 *  Copyright (C) 2007 Cameron Zwarich (cwzwarich@uwaterloo.ca)
 *  Copyright (C) 2007 Maks Orlovich
 *  Copyright (C) 2007 Eric Seidel <eric@webkit.org>


@@ -40,12 +40,14 @@
 #include "LabelScope.h"
 #include "Lexer.h"
 #include "JSCInlines.h"
 #include "LabelScope.h"
 #include "Lexer.h"
 #include "JSCInlines.h"

+#include "JSTemplateRegistryKey.h"

 #include "Parser.h"
 #include "PropertyNameArray.h"
 #include "RegExpCache.h"
 #include "RegExpObject.h"
 #include "SamplingTool.h"
 #include "StackAlignment.h"
 #include "Parser.h"
 #include "PropertyNameArray.h"
 #include "RegExpCache.h"
 #include "RegExpObject.h"
 #include "SamplingTool.h"
 #include "StackAlignment.h"

+#include "TemplateRegistryKey.h"

 #include <wtf/Assertions.h>
 #include <wtf/RefCountedLeakCounter.h>
 #include <wtf/Threading.h>
 #include <wtf/Assertions.h>
 #include <wtf/RefCountedLeakCounter.h>
 #include <wtf/Threading.h>


@@ -122,6 +124,15 @@ JSValue StringNode::jsValue(BytecodeGenerator& generator) const
     return generator.addStringConstant(m_value);
 }
 
     return generator.addStringConstant(m_value);
 }
 

+// ------------------------------ NumberNode ----------------------------------
+
+RegisterID* NumberNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
+{
+    if (dst == generator.ignoredResult())
+        return nullptr;
+    return generator.emitLoad(dst, jsValue(generator), isIntegerNode() ? SourceCodeRepresentation::Integer : SourceCodeRepresentation::Double);
+}
+

 // ------------------------------ RegExpNode -----------------------------------
 
 RegisterID* RegExpNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
 // ------------------------------ RegExpNode -----------------------------------
 
 RegisterID* RegExpNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)


@@ -135,31 +146,184 @@ RegisterID* RegExpNode::emitBytecode(BytecodeGenerator& generator, RegisterID* d
 
 RegisterID* ThisNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
 {
 
 RegisterID* ThisNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
 {

+    if (m_shouldAlwaysEmitTDZCheck || generator.constructorKind() == ConstructorKind::Derived)
+        generator.emitTDZCheck(generator.thisRegister());
+

     if (dst == generator.ignoredResult())
         return 0;
     if (dst == generator.ignoredResult())
         return 0;

-    return generator.moveToDestinationIfNeeded(dst, generator.thisRegister());
+
+    RegisterID* result = generator.moveToDestinationIfNeeded(dst, generator.thisRegister());
+    if (generator.vm()->typeProfiler()) {
+        generator.emitProfileType(generator.thisRegister(), ProfileTypeBytecodeDoesNotHaveGlobalID, nullptr);
+        static const unsigned thisLength = 4;
+        generator.emitTypeProfilerExpressionInfo(position(), JSTextPosition(-1, position().offset + thisLength, -1));
+    }
+    return result;
+}
+
+// ------------------------------ SuperNode -------------------------------------
+
+RegisterID* SuperNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
+{
+    if (dst == generator.ignoredResult())
+        return 0;
+
+    RegisterID callee;
+    callee.setIndex(JSStack::Callee);
+
+    RefPtr<RegisterID> homeObject = generator.emitGetById(generator.newTemporary(), &callee, generator.propertyNames().homeObjectPrivateName);
+    RefPtr<RegisterID> protoParent = generator.emitGetById(generator.newTemporary(), homeObject.get(), generator.propertyNames().underscoreProto);
+    return generator.emitGetById(generator.finalDestination(dst), protoParent.get(), generator.propertyNames().constructor);
+}
+
+static RegisterID* emitSuperBaseForCallee(BytecodeGenerator& generator)
+{
+    RegisterID callee;
+    callee.setIndex(JSStack::Callee);
+
+    RefPtr<RegisterID> homeObject = generator.emitGetById(generator.newTemporary(), &callee, generator.propertyNames().homeObjectPrivateName);
+    return generator.emitGetById(generator.newTemporary(), homeObject.get(), generator.propertyNames().underscoreProto);

 }
 
 // ------------------------------ ResolveNode ----------------------------------
 
 bool ResolveNode::isPure(BytecodeGenerator& generator) const
 {
 }
 
 // ------------------------------ ResolveNode ----------------------------------
 
 bool ResolveNode::isPure(BytecodeGenerator& generator) const
 {

-    return generator.local(m_ident).get();
+    return generator.variable(m_ident).offset().isStack();

 }
 
 RegisterID* ResolveNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
 {
 }
 
 RegisterID* ResolveNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
 {

-    if (Local local = generator.local(m_ident)) {
+    Variable var = generator.variable(m_ident);
+    if (RegisterID* local = var.local()) {

         if (dst == generator.ignoredResult())
         if (dst == generator.ignoredResult())

-            return 0;
-        return generator.moveToDestinationIfNeeded(dst, local.get());
+            return nullptr;
+        if (generator.vm()->typeProfiler()) {
+            generator.emitProfileType(local, ProfileTypeBytecodeHasGlobalID, nullptr);
+            generator.emitTypeProfilerExpressionInfo(m_position, JSTextPosition(-1, m_position.offset + m_ident.length(), -1));
+        }
+        return generator.moveToDestinationIfNeeded(dst, local);

     }
     
     JSTextPosition divot = m_start + m_ident.length();
     generator.emitExpressionInfo(divot, m_start, divot);
     }
     
     JSTextPosition divot = m_start + m_ident.length();
     generator.emitExpressionInfo(divot, m_start, divot);

-    RefPtr<RegisterID> scope = generator.emitResolveScope(generator.tempDestination(dst), m_ident);
-    return generator.emitGetFromScope(generator.finalDestination(dst), scope.get(), m_ident, ThrowIfNotFound);
+    RefPtr<RegisterID> scope = generator.emitResolveScope(dst, var);
+    RegisterID* finalDest = generator.finalDestination(dst);
+    RegisterID* result = generator.emitGetFromScope(finalDest, scope.get(), var, ThrowIfNotFound);
+    if (generator.vm()->typeProfiler()) {
+        generator.emitProfileType(finalDest, var.isResolved() ? ProfileTypeBytecodeGetFromLocalScope : ProfileTypeBytecodeGetFromScope, &m_ident);
+        generator.emitTypeProfilerExpressionInfo(m_position, JSTextPosition(-1, m_position.offset + m_ident.length(), -1));
+    }
+    return result;
+}
+
+#if ENABLE(ES6_TEMPLATE_LITERAL_SYNTAX)
+// ------------------------------ TemplateStringNode -----------------------------------
+
+RegisterID* TemplateStringNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
+{
+    if (dst == generator.ignoredResult())
+        return nullptr;
+    return generator.emitLoad(dst, JSValue(generator.addStringConstant(cooked())));
+}
+
+// ------------------------------ TemplateLiteralNode -----------------------------------
+
+RegisterID* TemplateLiteralNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
+{
+    if (!m_templateExpressions) {
+        TemplateStringNode* templateString = m_templateStrings->value();
+        ASSERT_WITH_MESSAGE(!m_templateStrings->next(), "Only one template element exists because there's no expression in a given template literal.");
+        return generator.emitNode(dst, templateString);
+    }
+
+    Vector<RefPtr<RegisterID>, 16> temporaryRegisters;
+
+    TemplateStringListNode* templateString = m_templateStrings;
+    TemplateExpressionListNode* templateExpression = m_templateExpressions;
+    for (; templateExpression; templateExpression = templateExpression->next(), templateString = templateString->next()) {
+        // Evaluate TemplateString.
+        if (!templateString->value()->cooked().isEmpty()) {
+            temporaryRegisters.append(generator.newTemporary());
+            generator.emitNode(temporaryRegisters.last().get(), templateString->value());
+        }
+
+        // Evaluate Expression.
+        temporaryRegisters.append(generator.newTemporary());
+        generator.emitNode(temporaryRegisters.last().get(), templateExpression->value());
+        generator.emitToString(temporaryRegisters.last().get(), temporaryRegisters.last().get());
+    }
+
+    // Evaluate tail TemplateString.
+    if (!templateString->value()->cooked().isEmpty()) {
+        temporaryRegisters.append(generator.newTemporary());
+        generator.emitNode(temporaryRegisters.last().get(), templateString->value());
+    }
+
+    return generator.emitStrcat(generator.finalDestination(dst, temporaryRegisters[0].get()), temporaryRegisters[0].get(), temporaryRegisters.size());
+}
+
+// ------------------------------ TaggedTemplateNode -----------------------------------
+
+RegisterID* TaggedTemplateNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
+{
+    ExpectedFunction expectedFunction = NoExpectedFunction;
+    RefPtr<RegisterID> tag = nullptr;
+    RefPtr<RegisterID> base = nullptr;
+    if (!m_tag->isLocation()) {
+        tag = generator.newTemporary();
+        tag = generator.emitNode(tag.get(), m_tag);
+    } else if (m_tag->isResolveNode()) {
+        ResolveNode* resolve = static_cast<ResolveNode*>(m_tag);
+        const Identifier& identifier = resolve->identifier();
+        expectedFunction = generator.expectedFunctionForIdentifier(identifier);
+
+        Variable var = generator.variable(identifier);
+        if (RegisterID* local = var.local())
+            tag = generator.emitMove(generator.newTemporary(), local);
+        else {
+            tag = generator.newTemporary();
+            base = generator.newTemporary();
+
+            JSTextPosition newDivot = divotStart() + identifier.length();
+            generator.emitExpressionInfo(newDivot, divotStart(), newDivot);
+            generator.moveToDestinationIfNeeded(base.get(), generator.emitResolveScope(base.get(), var));
+            generator.emitGetFromScope(tag.get(), base.get(), var, ThrowIfNotFound);
+        }
+    } else if (m_tag->isBracketAccessorNode()) {
+        BracketAccessorNode* bracket = static_cast<BracketAccessorNode*>(m_tag);
+        base = generator.newTemporary();
+        base = generator.emitNode(base.get(), bracket->base());
+        RefPtr<RegisterID> property = generator.emitNode(bracket->subscript());
+        tag = generator.emitGetByVal(generator.newTemporary(), base.get(), property.get());
+    } else {
+        ASSERT(m_tag->isDotAccessorNode());
+        DotAccessorNode* dot = static_cast<DotAccessorNode*>(m_tag);
+        base = generator.newTemporary();
+        base = generator.emitNode(base.get(), dot->base());
+        tag = generator.emitGetById(generator.newTemporary(), base.get(), dot->identifier());
+    }
+
+    RefPtr<RegisterID> templateObject = generator.emitGetTemplateObject(generator.newTemporary(), this);
+
+    unsigned expressionsCount = 0;
+    for (TemplateExpressionListNode* templateExpression = m_templateLiteral->templateExpressions(); templateExpression; templateExpression = templateExpression->next())
+        ++expressionsCount;
+
+    CallArguments callArguments(generator, nullptr, 1 + expressionsCount);
+    if (base)
+        generator.emitMove(callArguments.thisRegister(), base.get());
+    else
+        generator.emitLoad(callArguments.thisRegister(), jsUndefined());
+
+    unsigned argumentIndex = 0;
+    generator.emitMove(callArguments.argumentRegister(argumentIndex++), templateObject.get());
+    for (TemplateExpressionListNode* templateExpression = m_templateLiteral->templateExpressions(); templateExpression; templateExpression = templateExpression->next())
+        generator.emitNode(callArguments.argumentRegister(argumentIndex++), templateExpression->value());
+
+    return generator.emitCall(generator.finalDestination(dst, tag.get()), tag.get(), expectedFunction, callArguments, divot(), divotStart(), divotEnd());

 }
 }

+#endif

 
 // ------------------------------ ArrayNode ------------------------------------
 
 
 // ------------------------------ ArrayNode ------------------------------------
 


@@ -232,7 +396,7 @@ bool ArrayNode::isSimpleArray() const
     return true;
 }
 
     return true;
 }
 

-ArgumentListNode* ArrayNode::toArgumentList(VM* vm, int lineNumber, int startPosition) const
+ArgumentListNode* ArrayNode::toArgumentList(ParserArena& parserArena, int lineNumber, int startPosition) const

 {
     ASSERT(!m_elision && !m_optional);
     ElementNode* ptr = m_element;
 {
     ASSERT(!m_elision && !m_optional);
     ElementNode* ptr = m_element;


@@ -241,12 +405,12 @@ ArgumentListNode* ArrayNode::toArgumentList(VM* vm, int lineNumber, int startPos
     JSTokenLocation location;
     location.line = lineNumber;
     location.startOffset = startPosition;
     JSTokenLocation location;
     location.line = lineNumber;
     location.startOffset = startPosition;

-    ArgumentListNode* head = new (vm) ArgumentListNode(location, ptr->value());
+    ArgumentListNode* head = new (parserArena) ArgumentListNode(location, ptr->value());

     ArgumentListNode* tail = head;
     ptr = ptr->next();
     for (; ptr; ptr = ptr->next()) {
         ASSERT(!ptr->elision());
     ArgumentListNode* tail = head;
     ptr = ptr->next();
     for (; ptr; ptr = ptr->next()) {
         ASSERT(!ptr->elision());

-        tail = new (vm) ArgumentListNode(location, tail, ptr->value());
+        tail = new (parserArena) ArgumentListNode(location, tail, ptr->value());

     }
     return head;
 }
     }
     return head;
 }


@@ -255,49 +419,59 @@ ArgumentListNode* ArrayNode::toArgumentList(VM* vm, int lineNumber, int startPos
 
 RegisterID* ObjectLiteralNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
 {
 
 RegisterID* ObjectLiteralNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
 {

-     if (!m_list) {
-         if (dst == generator.ignoredResult())
-             return 0;
-         return generator.emitNewObject(generator.finalDestination(dst));
-     }
-     return generator.emitNode(dst, m_list);
+    if (!m_list) {
+        if (dst == generator.ignoredResult())
+            return 0;
+        return generator.emitNewObject(generator.finalDestination(dst));
+    }
+    RefPtr<RegisterID> newObj = generator.emitNewObject(generator.tempDestination(dst));
+    generator.emitNode(newObj.get(), m_list);
+    return generator.moveToDestinationIfNeeded(dst, newObj.get());

 }
 
 // ------------------------------ PropertyListNode -----------------------------
 
 }
 
 // ------------------------------ PropertyListNode -----------------------------
 

+static inline void emitPutHomeObject(BytecodeGenerator& generator, RegisterID* function, RegisterID* homeObject)
+{
+    generator.emitPutById(function, generator.propertyNames().homeObjectPrivateName, homeObject);
+}
+

 RegisterID* PropertyListNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
 {
 RegisterID* PropertyListNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
 {

-    RefPtr<RegisterID> newObj = generator.tempDestination(dst);
-    
-    generator.emitNewObject(newObj.get());
-    

     // Fast case: this loop just handles regular value properties.
     PropertyListNode* p = this;
     // Fast case: this loop just handles regular value properties.
     PropertyListNode* p = this;

-    for (; p && p->m_node->m_type == PropertyNode::Constant; p = p->m_next) {
-        if (p->m_node->m_name) {
-            generator.emitDirectPutById(newObj.get(), *p->m_node->name(), generator.emitNode(p->m_node->m_assign));
-            continue;
-        }
-        RefPtr<RegisterID> propertyName = generator.emitNode(p->m_node->m_expression);
-        generator.emitDirectPutByVal(newObj.get(), propertyName.get(), generator.emitNode(p->m_node->m_assign));
-    }
+    for (; p && (p->m_node->m_type & PropertyNode::Constant); p = p->m_next)
+        emitPutConstantProperty(generator, dst, *p->m_node);

 
     // Were there any get/set properties?
     if (p) {
 
     // Were there any get/set properties?
     if (p) {

+        // Build a list of getter/setter pairs to try to put them at the same time. If we encounter
+        // a computed property, just emit everything as that may override previous values.
+        bool hasComputedProperty = false;
+

         typedef std::pair<PropertyNode*, PropertyNode*> GetterSetterPair;
         typedef std::pair<PropertyNode*, PropertyNode*> GetterSetterPair;

-        typedef HashMap<StringImpl*, GetterSetterPair> GetterSetterMap;
+        typedef HashMap<UniquedStringImpl*, GetterSetterPair, IdentifierRepHash> GetterSetterMap;

         GetterSetterMap map;
 
         // Build a map, pairing get/set values together.
         for (PropertyListNode* q = p; q; q = q->m_next) {
             PropertyNode* node = q->m_node;
         GetterSetterMap map;
 
         // Build a map, pairing get/set values together.
         for (PropertyListNode* q = p; q; q = q->m_next) {
             PropertyNode* node = q->m_node;

-            if (node->m_type == PropertyNode::Constant)
+            if (node->m_type & PropertyNode::Computed) {
+                hasComputedProperty = true;
+                break;
+            }
+            if (node->m_type & PropertyNode::Constant)

                 continue;
 
                 continue;
 

-            GetterSetterPair pair(node, static_cast<PropertyNode*>(0));
+            // Duplicates are possible.
+            GetterSetterPair pair(node, static_cast<PropertyNode*>(nullptr));

             GetterSetterMap::AddResult result = map.add(node->name()->impl(), pair);
             GetterSetterMap::AddResult result = map.add(node->name()->impl(), pair);

-            if (!result.isNewEntry)
-                result.iterator->value.second = node;
+            if (!result.isNewEntry) {
+                if (result.iterator->value.first->m_type == node->m_type)
+                    result.iterator->value.first = node;
+                else
+                    result.iterator->value.second = node;
+            }

         }
 
         // Iterate over the remaining properties in the list.
         }
 
         // Iterate over the remaining properties in the list.


@@ -305,20 +479,28 @@ RegisterID* PropertyListNode::emitBytecode(BytecodeGenerator& generator, Registe
             PropertyNode* node = p->m_node;
 
             // Handle regular values.
             PropertyNode* node = p->m_node;
 
             // Handle regular values.

-            if (node->m_type == PropertyNode::Constant) {
-                if (node->name()) {
-                    generator.emitDirectPutById(newObj.get(), *node->name(), generator.emitNode(node->m_assign));
-                    continue;
-                }
-                RefPtr<RegisterID> propertyName = generator.emitNode(p->m_node->m_expression);
-                generator.emitDirectPutByVal(newObj.get(), propertyName.get(), generator.emitNode(p->m_node->m_assign));
+            if (node->m_type & PropertyNode::Constant) {
+                emitPutConstantProperty(generator, dst, *node);

                 continue;
             }
                 continue;
             }

-            
+

             RegisterID* value = generator.emitNode(node->m_assign);
             RegisterID* value = generator.emitNode(node->m_assign);

+            bool isClassProperty = node->needsSuperBinding();
+            if (isClassProperty)
+                emitPutHomeObject(generator, value, dst);
+
+            ASSERT(node->m_type & (PropertyNode::Getter | PropertyNode::Setter));
+
+            // This is a get/set property which may be overridden by a computed property later.
+            if (hasComputedProperty) {
+                if (node->m_type & PropertyNode::Getter)
+                    generator.emitPutGetterById(dst, *node->name(), value);
+                else
+                    generator.emitPutSetterById(dst, *node->name(), value);
+                continue;
+            }

 
 

-            // This is a get/set property, find its entry in the map.
-            ASSERT(node->m_type == PropertyNode::Getter || node->m_type == PropertyNode::Setter);
+            // This is a get/set property pair.

             GetterSetterMap::iterator it = map.find(node->name()->impl());
             ASSERT(it != map.end());
             GetterSetterPair& pair = it->value;
             GetterSetterMap::iterator it = map.find(node->name()->impl());
             ASSERT(it != map.end());
             GetterSetterPair& pair = it->value;


@@ -326,75 +508,129 @@ RegisterID* PropertyListNode::emitBytecode(BytecodeGenerator& generator, Registe
             // Was this already generated as a part of its partner?
             if (pair.second == node)
                 continue;
             // Was this already generated as a part of its partner?
             if (pair.second == node)
                 continue;

-    
+

             // Generate the paired node now.
             RefPtr<RegisterID> getterReg;
             RefPtr<RegisterID> setterReg;
             // Generate the paired node now.
             RefPtr<RegisterID> getterReg;
             RefPtr<RegisterID> setterReg;

+            RegisterID* secondReg = nullptr;

 
 

-            if (node->m_type == PropertyNode::Getter) {
+            if (node->m_type & PropertyNode::Getter) {

                 getterReg = value;
                 if (pair.second) {
                 getterReg = value;
                 if (pair.second) {

-                    ASSERT(pair.second->m_type == PropertyNode::Setter);
+                    ASSERT(pair.second->m_type & PropertyNode::Setter);

                     setterReg = generator.emitNode(pair.second->m_assign);
                     setterReg = generator.emitNode(pair.second->m_assign);

+                    secondReg = setterReg.get();

                 } else {
                     setterReg = generator.newTemporary();
                     generator.emitLoad(setterReg.get(), jsUndefined());
                 }
             } else {
                 } else {
                     setterReg = generator.newTemporary();
                     generator.emitLoad(setterReg.get(), jsUndefined());
                 }
             } else {

-                ASSERT(node->m_type == PropertyNode::Setter);
+                ASSERT(node->m_type & PropertyNode::Setter);

                 setterReg = value;
                 if (pair.second) {
                 setterReg = value;
                 if (pair.second) {

-                    ASSERT(pair.second->m_type == PropertyNode::Getter);
+                    ASSERT(pair.second->m_type & PropertyNode::Getter);

                     getterReg = generator.emitNode(pair.second->m_assign);
                     getterReg = generator.emitNode(pair.second->m_assign);

+                    secondReg = getterReg.get();

                 } else {
                     getterReg = generator.newTemporary();
                     generator.emitLoad(getterReg.get(), jsUndefined());
                 }
             }
 
                 } else {
                     getterReg = generator.newTemporary();
                     generator.emitLoad(getterReg.get(), jsUndefined());
                 }
             }
 

-            generator.emitPutGetterSetter(newObj.get(), *node->name(), getterReg.get(), setterReg.get());
+            ASSERT(!pair.second || isClassProperty == pair.second->needsSuperBinding());
+            if (isClassProperty && pair.second)
+                emitPutHomeObject(generator, secondReg, dst);
+
+            if (isClassProperty) {
+                RefPtr<RegisterID> propertyNameRegister = generator.emitLoad(generator.newTemporary(), *node->name());
+                generator.emitCallDefineProperty(dst, propertyNameRegister.get(),
+                    nullptr, getterReg.get(), setterReg.get(), BytecodeGenerator::PropertyConfigurable, m_position);
+            } else
+                generator.emitPutGetterSetter(dst, *node->name(), getterReg.get(), setterReg.get());

         }
     }
 
         }
     }
 

-    return generator.moveToDestinationIfNeeded(dst, newObj.get());
+    return dst;
+}
+
+void PropertyListNode::emitPutConstantProperty(BytecodeGenerator& generator, RegisterID* newObj, PropertyNode& node)
+{
+    RefPtr<RegisterID> value = generator.emitNode(node.m_assign);
+    if (node.needsSuperBinding()) {
+        emitPutHomeObject(generator, value.get(), newObj);
+
+        RefPtr<RegisterID> propertyNameRegister;
+        if (node.name())
+            propertyNameRegister = generator.emitLoad(generator.newTemporary(), *node.name());
+        else
+            propertyNameRegister = generator.emitNode(node.m_expression);
+
+        generator.emitCallDefineProperty(newObj, propertyNameRegister.get(),
+            value.get(), nullptr, nullptr, BytecodeGenerator::PropertyConfigurable | BytecodeGenerator::PropertyWritable, m_position);
+        return;
+    }
+    if (const auto* identifier = node.name()) {
+        Optional<uint32_t> optionalIndex = parseIndex(*identifier);
+        if (!optionalIndex) {
+            generator.emitDirectPutById(newObj, *identifier, value.get(), node.putType());
+            return;
+        }
+
+        RefPtr<RegisterID> index = generator.emitLoad(generator.newTemporary(), jsNumber(optionalIndex.value()));
+        generator.emitDirectPutByVal(newObj, index.get(), value.get());
+        return;
+    }
+    RefPtr<RegisterID> propertyName = generator.emitNode(node.m_expression);
+    generator.emitDirectPutByVal(newObj, propertyName.get(), value.get());

 }
 
 // ------------------------------ BracketAccessorNode --------------------------------
 
 RegisterID* BracketAccessorNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
 {
 }
 
 // ------------------------------ BracketAccessorNode --------------------------------
 
 RegisterID* BracketAccessorNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
 {

-    if (m_base->isResolveNode() 
-        && generator.willResolveToArguments(static_cast<ResolveNode*>(m_base)->identifier())
-        && !generator.symbolTable().slowArguments()) {
+    if (m_base->isSuperNode()) {
+        // FIXME: Should we generate the profiler info?
+        if (m_subscript->isString()) {
+            const Identifier& id = static_cast<StringNode*>(m_subscript)->value();
+            return generator.emitGetById(generator.finalDestination(dst), emitSuperBaseForCallee(generator), id);
+        }
+        return generator.emitGetByVal(generator.finalDestination(dst), emitSuperBaseForCallee(generator), generator.emitNode(m_subscript));
+    }
+
+    RegisterID* ret;
+    RegisterID* finalDest = generator.finalDestination(dst);
+
+    if (m_subscript->isString()) {
+        RefPtr<RegisterID> base = generator.emitNode(m_base);
+        ret = generator.emitGetById(finalDest, base.get(), static_cast<StringNode*>(m_subscript)->value());
+    } else {
+        RefPtr<RegisterID> base = generator.emitNodeForLeftHandSide(m_base, m_subscriptHasAssignments, m_subscript->isPure(generator));

         RegisterID* property = generator.emitNode(m_subscript);
         RegisterID* property = generator.emitNode(m_subscript);

-        generator.emitExpressionInfo(divot(), divotStart(), divotEnd());
-        return generator.emitGetArgumentByVal(generator.finalDestination(dst), generator.uncheckedRegisterForArguments(), property);
+        ret = generator.emitGetByVal(finalDest, base.get(), property);

     }
 
     }
 

-    RefPtr<RegisterID> base = generator.emitNodeForLeftHandSide(m_base, m_subscriptHasAssignments, m_subscript->isPure(generator));
-    RegisterID* property = generator.emitNode(m_subscript);

     generator.emitExpressionInfo(divot(), divotStart(), divotEnd());
     generator.emitExpressionInfo(divot(), divotStart(), divotEnd());

-    return generator.emitGetByVal(generator.finalDestination(dst), base.get(), property);
+
+    if (generator.vm()->typeProfiler()) {
+        generator.emitProfileType(finalDest, ProfileTypeBytecodeDoesNotHaveGlobalID, nullptr);
+        generator.emitTypeProfilerExpressionInfo(divotStart(), divotEnd());
+    }
+    return ret;

 }
 
 // ------------------------------ DotAccessorNode --------------------------------
 
 RegisterID* DotAccessorNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
 {
 }
 
 // ------------------------------ DotAccessorNode --------------------------------
 
 RegisterID* DotAccessorNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
 {

-    if (m_ident == generator.propertyNames().length) {
-        if (!m_base->isResolveNode())
-            goto nonArgumentsPath;
-        ResolveNode* resolveNode = static_cast<ResolveNode*>(m_base);
-        if (!generator.willResolveToArguments(resolveNode->identifier()))
-            goto nonArgumentsPath;
-        generator.emitExpressionInfo(divot(), divotStart(), divotEnd());
-        return generator.emitGetArgumentsLength(generator.finalDestination(dst), generator.uncheckedRegisterForArguments());
-    }
-
-nonArgumentsPath:
-    RegisterID* base = generator.emitNode(m_base);
+    RefPtr<RegisterID> base = m_base->isSuperNode() ? emitSuperBaseForCallee(generator) : generator.emitNode(m_base);

     generator.emitExpressionInfo(divot(), divotStart(), divotEnd());
     generator.emitExpressionInfo(divot(), divotStart(), divotEnd());

-    return generator.emitGetById(generator.finalDestination(dst), base, m_ident);
+    RegisterID* finalDest = generator.finalDestination(dst);
+    RegisterID* ret = generator.emitGetById(finalDest, base.get(), m_ident);
+    if (generator.vm()->typeProfiler()) {
+        generator.emitProfileType(finalDest, ProfileTypeBytecodeDoesNotHaveGlobalID, nullptr);
+        generator.emitTypeProfilerExpressionInfo(divotStart(), divotEnd());
+    }
+    return ret;

 }
 
 // ------------------------------ ArgumentListNode -----------------------------
 }
 
 // ------------------------------ ArgumentListNode -----------------------------


@@ -417,6 +653,7 @@ RegisterID* NewExprNode::emitBytecode(BytecodeGenerator& generator, RegisterID*
     RefPtr<RegisterID> func = generator.emitNode(m_expr);
     RefPtr<RegisterID> returnValue = generator.finalDestination(dst, func.get());
     CallArguments callArguments(generator, m_args);
     RefPtr<RegisterID> func = generator.emitNode(m_expr);
     RefPtr<RegisterID> returnValue = generator.finalDestination(dst, func.get());
     CallArguments callArguments(generator, m_args);

+    generator.emitMove(callArguments.thisRegister(), func.get());

     return generator.emitConstruct(returnValue.get(), func.get(), expectedFunction, callArguments, divot(), divotStart(), divotEnd());
 }
 
     return generator.emitConstruct(returnValue.get(), func.get(), expectedFunction, callArguments, divot(), divotStart(), divotEnd());
 }
 


@@ -449,8 +686,9 @@ CallArguments::CallArguments(BytecodeGenerator& generator, ArgumentsNode* argume
 
 RegisterID* EvalFunctionCallNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
 {
 
 RegisterID* EvalFunctionCallNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
 {

-    if (Local local = generator.local(generator.propertyNames().eval)) {
-        RefPtr<RegisterID> func = generator.emitMove(generator.tempDestination(dst), local.get());
+    Variable var = generator.variable(generator.propertyNames().eval);
+    if (RegisterID* local = var.local()) {
+        RefPtr<RegisterID> func = generator.emitMove(generator.tempDestination(dst), local);

         CallArguments callArguments(generator, m_args);
         generator.emitLoad(callArguments.thisRegister(), jsUndefined());
         return generator.emitCallEval(generator.finalDestination(dst, func.get()), func.get(), callArguments, divot(), divotStart(), divotEnd());
         CallArguments callArguments(generator, m_args);
         generator.emitLoad(callArguments.thisRegister(), jsUndefined());
         return generator.emitCallEval(generator.finalDestination(dst, func.get()), func.get(), callArguments, divot(), divotStart(), divotEnd());


@@ -460,8 +698,10 @@ RegisterID* EvalFunctionCallNode::emitBytecode(BytecodeGenerator& generator, Reg
     CallArguments callArguments(generator, m_args);
     JSTextPosition newDivot = divotStart() + 4;
     generator.emitExpressionInfo(newDivot, divotStart(), newDivot);
     CallArguments callArguments(generator, m_args);
     JSTextPosition newDivot = divotStart() + 4;
     generator.emitExpressionInfo(newDivot, divotStart(), newDivot);

-    generator.emitResolveScope(callArguments.thisRegister(), generator.propertyNames().eval);
-    generator.emitGetFromScope(func.get(), callArguments.thisRegister(), generator.propertyNames().eval, ThrowIfNotFound);
+    generator.moveToDestinationIfNeeded(
+        callArguments.thisRegister(),
+        generator.emitResolveScope(callArguments.thisRegister(), var));
+    generator.emitGetFromScope(func.get(), callArguments.thisRegister(), var, ThrowIfNotFound);

     return generator.emitCallEval(generator.finalDestination(dst, func.get()), func.get(), callArguments, divot(), divotStart(), divotEnd());
 }
 
     return generator.emitCallEval(generator.finalDestination(dst, func.get()), func.get(), callArguments, divot(), divotStart(), divotEnd());
 }
 


@@ -472,8 +712,21 @@ RegisterID* FunctionCallValueNode::emitBytecode(BytecodeGenerator& generator, Re
     RefPtr<RegisterID> func = generator.emitNode(m_expr);
     RefPtr<RegisterID> returnValue = generator.finalDestination(dst, func.get());
     CallArguments callArguments(generator, m_args);
     RefPtr<RegisterID> func = generator.emitNode(m_expr);
     RefPtr<RegisterID> returnValue = generator.finalDestination(dst, func.get());
     CallArguments callArguments(generator, m_args);

+    if (m_expr->isSuperNode()) {
+        ASSERT(generator.isConstructor());
+        ASSERT(generator.constructorKind() == ConstructorKind::Derived);
+        generator.emitMove(callArguments.thisRegister(), generator.newTarget());
+        RegisterID* ret = generator.emitConstruct(returnValue.get(), func.get(), NoExpectedFunction, callArguments, divot(), divotStart(), divotEnd());
+        generator.emitMove(generator.thisRegister(), ret);
+        return ret;
+    }

     generator.emitLoad(callArguments.thisRegister(), jsUndefined());
     generator.emitLoad(callArguments.thisRegister(), jsUndefined());

-    return generator.emitCall(returnValue.get(), func.get(), NoExpectedFunction, callArguments, divot(), divotStart(), divotEnd());
+    RegisterID* ret = generator.emitCall(returnValue.get(), func.get(), NoExpectedFunction, callArguments, divot(), divotStart(), divotEnd());
+    if (generator.vm()->typeProfiler()) {
+        generator.emitProfileType(returnValue.get(), ProfileTypeBytecodeDoesNotHaveGlobalID, nullptr);
+        generator.emitTypeProfilerExpressionInfo(divotStart(), divotEnd());
+    }
+    return ret;

 }
 
 // ------------------------------ FunctionCallResolveNode ----------------------------------
 }
 
 // ------------------------------ FunctionCallResolveNode ----------------------------------


@@ -482,14 +735,20 @@ RegisterID* FunctionCallResolveNode::emitBytecode(BytecodeGenerator& generator,
 {
     ExpectedFunction expectedFunction = generator.expectedFunctionForIdentifier(m_ident);
 
 {
     ExpectedFunction expectedFunction = generator.expectedFunctionForIdentifier(m_ident);
 

-    if (Local local = generator.local(m_ident)) {
-        RefPtr<RegisterID> func = generator.emitMove(generator.tempDestination(dst), local.get());
+    Variable var = generator.variable(m_ident);
+    if (RegisterID* local = var.local()) {
+        RefPtr<RegisterID> func = generator.emitMove(generator.tempDestination(dst), local);

         RefPtr<RegisterID> returnValue = generator.finalDestination(dst, func.get());
         CallArguments callArguments(generator, m_args);
         generator.emitLoad(callArguments.thisRegister(), jsUndefined());
         // This passes NoExpectedFunction because we expect that if the function is in a
         // local variable, then it's not one of our built-in constructors.
         RefPtr<RegisterID> returnValue = generator.finalDestination(dst, func.get());
         CallArguments callArguments(generator, m_args);
         generator.emitLoad(callArguments.thisRegister(), jsUndefined());
         // This passes NoExpectedFunction because we expect that if the function is in a
         // local variable, then it's not one of our built-in constructors.

-        return generator.emitCall(returnValue.get(), func.get(), NoExpectedFunction, callArguments, divot(), divotStart(), divotEnd());
+        RegisterID* ret = generator.emitCall(returnValue.get(), func.get(), NoExpectedFunction, callArguments, divot(), divotStart(), divotEnd());
+        if (generator.vm()->typeProfiler()) {
+            generator.emitProfileType(returnValue.get(), ProfileTypeBytecodeDoesNotHaveGlobalID, nullptr);
+            generator.emitTypeProfilerExpressionInfo(divotStart(), divotEnd());
+        }
+        return ret;

     }
 
     RefPtr<RegisterID> func = generator.newTemporary();
     }
 
     RefPtr<RegisterID> func = generator.newTemporary();


@@ -498,23 +757,87 @@ RegisterID* FunctionCallResolveNode::emitBytecode(BytecodeGenerator& generator,
 
     JSTextPosition newDivot = divotStart() + m_ident.length();
     generator.emitExpressionInfo(newDivot, divotStart(), newDivot);
 
     JSTextPosition newDivot = divotStart() + m_ident.length();
     generator.emitExpressionInfo(newDivot, divotStart(), newDivot);

-    generator.emitResolveScope(callArguments.thisRegister(), m_ident);
-    generator.emitGetFromScope(func.get(), callArguments.thisRegister(), m_ident, ThrowIfNotFound);
-    return generator.emitCall(returnValue.get(), func.get(), expectedFunction, callArguments, divot(), divotStart(), divotEnd());
+    generator.moveToDestinationIfNeeded(
+        callArguments.thisRegister(),
+        generator.emitResolveScope(callArguments.thisRegister(), var));
+    generator.emitGetFromScope(func.get(), callArguments.thisRegister(), var, ThrowIfNotFound);
+    RegisterID* ret = generator.emitCall(returnValue.get(), func.get(), expectedFunction, callArguments, divot(), divotStart(), divotEnd());
+    if (generator.vm()->typeProfiler()) {
+        generator.emitProfileType(returnValue.get(), ProfileTypeBytecodeDoesNotHaveGlobalID, nullptr);
+        generator.emitTypeProfilerExpressionInfo(divotStart(), divotEnd());
+    }
+    return ret;
+}
+
+// ------------------------------ BytecodeIntrinsicNode ----------------------------------
+
+RegisterID* BytecodeIntrinsicNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
+{
+    return (this->*m_emitter)(generator, dst);
+}
+
+RegisterID* BytecodeIntrinsicNode::emit_intrinsic_putByValDirect(BytecodeGenerator& generator, RegisterID* dst)
+{
+    ArgumentListNode* node = m_args->m_listNode;
+    RefPtr<RegisterID> base = generator.emitNode(node);
+    node = node->m_next;
+    RefPtr<RegisterID> index = generator.emitNode(node);
+    node = node->m_next;
+    RefPtr<RegisterID> value = generator.emitNode(node);
+
+    ASSERT(!node->m_next);
+
+    return generator.moveToDestinationIfNeeded(dst, generator.emitDirectPutByVal(base.get(), index.get(), value.get()));
+}
+
+RegisterID* BytecodeIntrinsicNode::emit_intrinsic_toString(BytecodeGenerator& generator, RegisterID* dst)
+{
+    ArgumentListNode* node = m_args->m_listNode;
+    RefPtr<RegisterID> src = generator.emitNode(node);
+    ASSERT(!node->m_next);
+
+    return generator.moveToDestinationIfNeeded(dst, generator.emitToString(generator.tempDestination(dst), src.get()));

 }
 
 // ------------------------------ FunctionCallBracketNode ----------------------------------
 
 RegisterID* FunctionCallBracketNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
 {
 }
 
 // ------------------------------ FunctionCallBracketNode ----------------------------------
 
 RegisterID* FunctionCallBracketNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
 {

-    RefPtr<RegisterID> base = generator.emitNode(m_base);
-    RegisterID* property = generator.emitNode(m_subscript);
-    generator.emitExpressionInfo(subexpressionDivot(), subexpressionStart(), subexpressionEnd());
-    RefPtr<RegisterID> function = generator.emitGetByVal(generator.tempDestination(dst), base.get(), property);
+    bool baseIsSuper = m_base->isSuperNode();
+    bool subscriptIsString = m_subscript->isString();
+
+    RefPtr<RegisterID> base;
+    if (baseIsSuper)
+        base = emitSuperBaseForCallee(generator);
+    else {
+        if (subscriptIsString)
+            base = generator.emitNode(m_base);
+        else
+            base = generator.emitNodeForLeftHandSide(m_base, m_subscriptHasAssignments, m_subscript->isPure(generator));
+    }
+
+    RefPtr<RegisterID> function;
+    if (subscriptIsString) {
+        generator.emitExpressionInfo(subexpressionDivot(), subexpressionStart(), subexpressionEnd());
+        function = generator.emitGetById(generator.tempDestination(dst), base.get(), static_cast<StringNode*>(m_subscript)->value());
+    } else {
+        RefPtr<RegisterID> property = generator.emitNode(m_subscript);
+        generator.emitExpressionInfo(subexpressionDivot(), subexpressionStart(), subexpressionEnd());
+        function = generator.emitGetByVal(generator.tempDestination(dst), base.get(), property.get());
+    }
+

     RefPtr<RegisterID> returnValue = generator.finalDestination(dst, function.get());
     CallArguments callArguments(generator, m_args);
     RefPtr<RegisterID> returnValue = generator.finalDestination(dst, function.get());
     CallArguments callArguments(generator, m_args);

-    generator.emitMove(callArguments.thisRegister(), base.get());
-    return generator.emitCall(returnValue.get(), function.get(), NoExpectedFunction, callArguments, divot(), divotStart(), divotEnd());
+    if (baseIsSuper)
+        generator.emitMove(callArguments.thisRegister(), generator.thisRegister());
+    else
+        generator.emitMove(callArguments.thisRegister(), base.get());
+    RegisterID* ret = generator.emitCall(returnValue.get(), function.get(), NoExpectedFunction, callArguments, divot(), divotStart(), divotEnd());
+    if (generator.vm()->typeProfiler()) {
+        generator.emitProfileType(returnValue.get(), ProfileTypeBytecodeDoesNotHaveGlobalID, nullptr);
+        generator.emitTypeProfilerExpressionInfo(divotStart(), divotEnd());
+    }
+    return ret;

 }
 
 // ------------------------------ FunctionCallDotNode ----------------------------------
 }
 
 // ------------------------------ FunctionCallDotNode ----------------------------------


@@ -524,21 +847,19 @@ RegisterID* FunctionCallDotNode::emitBytecode(BytecodeGenerator& generator, Regi
     RefPtr<RegisterID> function = generator.tempDestination(dst);
     RefPtr<RegisterID> returnValue = generator.finalDestination(dst, function.get());
     CallArguments callArguments(generator, m_args);
     RefPtr<RegisterID> function = generator.tempDestination(dst);
     RefPtr<RegisterID> returnValue = generator.finalDestination(dst, function.get());
     CallArguments callArguments(generator, m_args);

-    generator.emitNode(callArguments.thisRegister(), m_base);
+    bool baseIsSuper = m_base->isSuperNode();
+    if (baseIsSuper)
+        generator.emitMove(callArguments.thisRegister(), generator.thisRegister());
+    else
+        generator.emitNode(callArguments.thisRegister(), m_base);

     generator.emitExpressionInfo(subexpressionDivot(), subexpressionStart(), subexpressionEnd());
     generator.emitExpressionInfo(subexpressionDivot(), subexpressionStart(), subexpressionEnd());

-    generator.emitGetById(function.get(), callArguments.thisRegister(), m_ident);
-    return generator.emitCall(returnValue.get(), function.get(), NoExpectedFunction, callArguments, divot(), divotStart(), divotEnd());
-}
-
-static RegisterID* getArgumentByVal(BytecodeGenerator& generator, ExpressionNode* base, RegisterID* property, RegisterID* dst, JSTextPosition divot, JSTextPosition divotStart, JSTextPosition divotEnd)
-{
-    if (base->isResolveNode()
-        && generator.willResolveToArguments(static_cast<ResolveNode*>(base)->identifier())
-        && !generator.symbolTable().slowArguments()) {
-        generator.emitExpressionInfo(divot, divotStart, divotEnd);
-        return generator.emitGetArgumentByVal(generator.finalDestination(dst), generator.uncheckedRegisterForArguments(), property);
+    generator.emitGetById(function.get(), baseIsSuper ? emitSuperBaseForCallee(generator) : callArguments.thisRegister(), m_ident);
+    RegisterID* ret = generator.emitCall(returnValue.get(), function.get(), NoExpectedFunction, callArguments, divot(), divotStart(), divotEnd());
+    if (generator.vm()->typeProfiler()) {
+        generator.emitProfileType(returnValue.get(), ProfileTypeBytecodeDoesNotHaveGlobalID, nullptr);
+        generator.emitTypeProfilerExpressionInfo(divotStart(), divotEnd());

     }
     }

-    return nullptr;
+    return ret;

 }
 
 RegisterID* CallFunctionCallDotNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
 }
 
 RegisterID* CallFunctionCallDotNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)


@@ -561,15 +882,10 @@ RegisterID* CallFunctionCallDotNode::emitBytecode(BytecodeGenerator& generator,
                 profileHookRegister = generator.newTemporary();
             SpreadExpressionNode* spread = static_cast<SpreadExpressionNode*>(m_args->m_listNode->m_expr);
             ExpressionNode* subject = spread->expression();
                 profileHookRegister = generator.newTemporary();
             SpreadExpressionNode* spread = static_cast<SpreadExpressionNode*>(m_args->m_listNode->m_expr);
             ExpressionNode* subject = spread->expression();

-            RefPtr<RegisterID> thisRegister = getArgumentByVal(generator, subject, generator.emitLoad(0, jsNumber(0)), 0, spread->divot(), spread->divotStart(), spread->divotEnd());

             RefPtr<RegisterID> argumentsRegister;
             RefPtr<RegisterID> argumentsRegister;

-            if (thisRegister)
-                argumentsRegister = generator.uncheckedRegisterForArguments();
-            else {
-                argumentsRegister = generator.emitNode(subject);
-                generator.emitExpressionInfo(spread->divot(), spread->divotStart(), spread->divotEnd());
-                thisRegister = generator.emitGetByVal(generator.newTemporary(), argumentsRegister.get(), generator.emitLoad(0, jsNumber(0)));
-            }
+            argumentsRegister = generator.emitNode(subject);
+            generator.emitExpressionInfo(spread->divot(), spread->divotStart(), spread->divotEnd());
+            RefPtr<RegisterID> thisRegister = generator.emitGetByVal(generator.newTemporary(), argumentsRegister.get(), generator.emitLoad(0, jsNumber(0)));

             generator.emitCallVarargs(returnValue.get(), base.get(), thisRegister.get(), argumentsRegister.get(), generator.newTemporary(), 1, profileHookRegister.get(), divot(), divotStart(), divotEnd());
         } else if (m_args->m_listNode && m_args->m_listNode->m_expr) {
             ArgumentListNode* oldList = m_args->m_listNode;
             generator.emitCallVarargs(returnValue.get(), base.get(), thisRegister.get(), argumentsRegister.get(), generator.newTemporary(), 1, profileHookRegister.get(), divot(), divotStart(), divotEnd());
         } else if (m_args->m_listNode && m_args->m_listNode->m_expr) {
             ArgumentListNode* oldList = m_args->m_listNode;


@@ -597,6 +913,10 @@ RegisterID* CallFunctionCallDotNode::emitBytecode(BytecodeGenerator& generator,
         }
         generator.emitLabel(end.get());
     }
         }
         generator.emitLabel(end.get());
     }

+    if (generator.vm()->typeProfiler()) {
+        generator.emitProfileType(returnValue.get(), ProfileTypeBytecodeDoesNotHaveGlobalID, nullptr);
+        generator.emitTypeProfilerExpressionInfo(divotStart(), divotEnd());
+    }

     return returnValue.get();
 }
 
     return returnValue.get();
 }
 


@@ -659,7 +979,7 @@ RegisterID* ApplyFunctionCallDotNode::emitBytecode(BytecodeGenerator& generator,
             } else if (m_args->m_listNode->m_next) {
                 ASSERT(m_args->m_listNode->m_next->m_expr->isSimpleArray());
                 ASSERT(!m_args->m_listNode->m_next->m_next);
             } else if (m_args->m_listNode->m_next) {
                 ASSERT(m_args->m_listNode->m_next->m_expr->isSimpleArray());
                 ASSERT(!m_args->m_listNode->m_next->m_next);

-                m_args->m_listNode = static_cast<ArrayNode*>(m_args->m_listNode->m_next->m_expr)->toArgumentList(generator.vm(), 0, 0);
+                m_args->m_listNode = static_cast<ArrayNode*>(m_args->m_listNode->m_next->m_expr)->toArgumentList(generator.parserArena(), 0, 0);

                 RefPtr<RegisterID> realFunction = generator.emitMove(generator.tempDestination(dst), base.get());
                 CallArguments callArguments(generator, m_args);
                 generator.emitNode(callArguments.thisRegister(), oldList->m_expr);
                 RefPtr<RegisterID> realFunction = generator.emitMove(generator.tempDestination(dst), base.get());
                 CallArguments callArguments(generator, m_args);
                 generator.emitNode(callArguments.thisRegister(), oldList->m_expr);


@@ -687,10 +1007,7 @@ RegisterID* ApplyFunctionCallDotNode::emitBytecode(BytecodeGenerator& generator,
         RefPtr<RegisterID> thisRegister = generator.emitNode(m_args->m_listNode->m_expr);
         RefPtr<RegisterID> argsRegister;
         ArgumentListNode* args = m_args->m_listNode->m_next;
         RefPtr<RegisterID> thisRegister = generator.emitNode(m_args->m_listNode->m_expr);
         RefPtr<RegisterID> argsRegister;
         ArgumentListNode* args = m_args->m_listNode->m_next;

-        if (args->m_expr->isResolveNode() && generator.willResolveToArguments(static_cast<ResolveNode*>(args->m_expr)->identifier()) && !generator.symbolTable().slowArguments())
-            argsRegister = generator.uncheckedRegisterForArguments();
-        else
-            argsRegister = generator.emitNode(args->m_expr);
+        argsRegister = generator.emitNode(args->m_expr);

 
         // Function.prototype.apply ignores extra arguments, but we still
         // need to evaluate them for side effects.
 
         // Function.prototype.apply ignores extra arguments, but we still
         // need to evaluate them for side effects.


@@ -707,6 +1024,10 @@ RegisterID* ApplyFunctionCallDotNode::emitBytecode(BytecodeGenerator& generator,
         generator.emitCall(returnValue.get(), function.get(), NoExpectedFunction, callArguments, divot(), divotStart(), divotEnd());
         generator.emitLabel(end.get());
     }
         generator.emitCall(returnValue.get(), function.get(), NoExpectedFunction, callArguments, divot(), divotStart(), divotEnd());
         generator.emitLabel(end.get());
     }

+    if (generator.vm()->typeProfiler()) {
+        generator.emitProfileType(returnValue.get(), ProfileTypeBytecodeDoesNotHaveGlobalID, nullptr);
+        generator.emitTypeProfilerExpressionInfo(divotStart(), divotEnd());
+    }

     return returnValue.get();
 }
 
     return returnValue.get();
 }
 


@@ -735,29 +1056,37 @@ RegisterID* PostfixNode::emitResolve(BytecodeGenerator& generator, RegisterID* d
     ResolveNode* resolve = static_cast<ResolveNode*>(m_expr);
     const Identifier& ident = resolve->identifier();
 
     ResolveNode* resolve = static_cast<ResolveNode*>(m_expr);
     const Identifier& ident = resolve->identifier();
 

-    if (Local local = generator.local(ident)) {
-        RegisterID* localReg = local.get();
-        if (local.isReadOnly()) {
+    Variable var = generator.variable(ident);
+    if (RegisterID* local = var.local()) {
+        RefPtr<RegisterID> localReg = local;
+        if (var.isReadOnly()) {

             generator.emitReadOnlyExceptionIfNeeded();
             generator.emitReadOnlyExceptionIfNeeded();

-            localReg = generator.emitMove(generator.tempDestination(dst), localReg);
-        } else if (local.isCaptured()) {
+            localReg = generator.emitMove(generator.tempDestination(dst), local);
+        } else if (generator.vm()->typeProfiler()) {

             RefPtr<RegisterID> tempDst = generator.finalDestination(dst);
             ASSERT(dst != localReg);
             RefPtr<RegisterID> tempDstSrc = generator.newTemporary();
             RefPtr<RegisterID> tempDst = generator.finalDestination(dst);
             ASSERT(dst != localReg);
             RefPtr<RegisterID> tempDstSrc = generator.newTemporary();

-            generator.emitToNumber(tempDst.get(), localReg);
-            generator.emitMove(tempDstSrc.get(), localReg);
+            generator.emitToNumber(tempDst.get(), localReg.get());
+            generator.emitMove(tempDstSrc.get(), localReg.get());

             emitIncOrDec(generator, tempDstSrc.get(), m_operator);
             emitIncOrDec(generator, tempDstSrc.get(), m_operator);

-            generator.emitMove(localReg, tempDstSrc.get());
+            generator.emitMove(localReg.get(), tempDstSrc.get());
+            if (generator.vm()->typeProfiler())
+                generator.emitTypeProfilerExpressionInfo(divotStart(), divotEnd());

             return tempDst.get();
         }
             return tempDst.get();
         }

-        return emitPostIncOrDec(generator, generator.finalDestination(dst), localReg, m_operator);
+        return emitPostIncOrDec(generator, generator.finalDestination(dst), localReg.get(), m_operator);

     }
 
     generator.emitExpressionInfo(divot(), divotStart(), divotEnd());
     }
 
     generator.emitExpressionInfo(divot(), divotStart(), divotEnd());

-    RefPtr<RegisterID> scope = generator.emitResolveScope(generator.newTemporary(), ident);
-    RefPtr<RegisterID> value = generator.emitGetFromScope(generator.newTemporary(), scope.get(), ident, ThrowIfNotFound);
+    RefPtr<RegisterID> scope = generator.emitResolveScope(nullptr, var);
+    RefPtr<RegisterID> value = generator.emitGetFromScope(generator.newTemporary(), scope.get(), var, ThrowIfNotFound);

     RefPtr<RegisterID> oldValue = emitPostIncOrDec(generator, generator.finalDestination(dst), value.get(), m_operator);
     RefPtr<RegisterID> oldValue = emitPostIncOrDec(generator, generator.finalDestination(dst), value.get(), m_operator);

-    generator.emitPutToScope(scope.get(), ident, value.get(), ThrowIfNotFound);
+    generator.emitPutToScope(scope.get(), var, value.get(), ThrowIfNotFound);
+    if (generator.vm()->typeProfiler()) {
+        generator.emitProfileType(value.get(), var.isResolved() ? ProfileTypeBytecodePutToLocalScope : ProfileTypeBytecodePutToScope, &ident);
+        generator.emitTypeProfilerExpressionInfo(divotStart(), divotEnd());
+    }
+

     return oldValue.get();
 }
 
     return oldValue.get();
 }
 


@@ -779,6 +1108,10 @@ RegisterID* PostfixNode::emitBracket(BytecodeGenerator& generator, RegisterID* d
     RegisterID* oldValue = emitPostIncOrDec(generator, generator.tempDestination(dst), value.get(), m_operator);
     generator.emitExpressionInfo(divot(), divotStart(), divotEnd());
     generator.emitPutByVal(base.get(), property.get(), value.get());
     RegisterID* oldValue = emitPostIncOrDec(generator, generator.tempDestination(dst), value.get(), m_operator);
     generator.emitExpressionInfo(divot(), divotStart(), divotEnd());
     generator.emitPutByVal(base.get(), property.get(), value.get());

+    if (generator.vm()->typeProfiler()) {
+        generator.emitProfileType(value.get(), ProfileTypeBytecodeDoesNotHaveGlobalID, nullptr);
+        generator.emitTypeProfilerExpressionInfo(divotStart(), divotEnd());
+    }

     return generator.moveToDestinationIfNeeded(dst, oldValue);
 }
 
     return generator.moveToDestinationIfNeeded(dst, oldValue);
 }
 


@@ -799,6 +1132,10 @@ RegisterID* PostfixNode::emitDot(BytecodeGenerator& generator, RegisterID* dst)
     RegisterID* oldValue = emitPostIncOrDec(generator, generator.tempDestination(dst), value.get(), m_operator);
     generator.emitExpressionInfo(divot(), divotStart(), divotEnd());
     generator.emitPutById(base.get(), ident, value.get());
     RegisterID* oldValue = emitPostIncOrDec(generator, generator.tempDestination(dst), value.get(), m_operator);
     generator.emitExpressionInfo(divot(), divotStart(), divotEnd());
     generator.emitPutById(base.get(), ident, value.get());

+    if (generator.vm()->typeProfiler()) {
+        generator.emitProfileType(value.get(), ProfileTypeBytecodeDoesNotHaveGlobalID, nullptr);
+        generator.emitTypeProfilerExpressionInfo(divotStart(), divotEnd());
+    }

     return generator.moveToDestinationIfNeeded(dst, oldValue);
 }
 
     return generator.moveToDestinationIfNeeded(dst, oldValue);
 }
 


@@ -814,19 +1151,20 @@ RegisterID* PostfixNode::emitBytecode(BytecodeGenerator& generator, RegisterID*
         return emitDot(generator, dst);
 
     return emitThrowReferenceError(generator, m_operator == OpPlusPlus
         return emitDot(generator, dst);
 
     return emitThrowReferenceError(generator, m_operator == OpPlusPlus

-        ? "Postfix ++ operator applied to value that is not a reference."
-        : "Postfix -- operator applied to value that is not a reference.");
+        ? ASCIILiteral("Postfix ++ operator applied to value that is not a reference.")
+        : ASCIILiteral("Postfix -- operator applied to value that is not a reference."));

 }
 
 // ------------------------------ DeleteResolveNode -----------------------------------
 
 RegisterID* DeleteResolveNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
 {
 }
 
 // ------------------------------ DeleteResolveNode -----------------------------------
 
 RegisterID* DeleteResolveNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
 {

-    if (generator.local(m_ident).get())
+    Variable var = generator.variable(m_ident);
+    if (var.local())

         return generator.emitLoad(generator.finalDestination(dst), false);
 
     generator.emitExpressionInfo(divot(), divotStart(), divotEnd());
         return generator.emitLoad(generator.finalDestination(dst), false);
 
     generator.emitExpressionInfo(divot(), divotStart(), divotEnd());

-    RefPtr<RegisterID> base = generator.emitResolveScope(generator.tempDestination(dst), m_ident);
+    RefPtr<RegisterID> base = generator.emitResolveScope(dst, var);

     return generator.emitDeleteById(generator.finalDestination(dst, base.get()), base.get(), m_ident);
 }
 
     return generator.emitDeleteById(generator.finalDestination(dst, base.get()), base.get(), m_ident);
 }
 


@@ -835,20 +1173,24 @@ RegisterID* DeleteResolveNode::emitBytecode(BytecodeGenerator& generator, Regist
 RegisterID* DeleteBracketNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
 {
     RefPtr<RegisterID> r0 = generator.emitNode(m_base);
 RegisterID* DeleteBracketNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
 {
     RefPtr<RegisterID> r0 = generator.emitNode(m_base);

-    RegisterID* r1 = generator.emitNode(m_subscript);
+    RefPtr<RegisterID> r1 = generator.emitNode(m_subscript);

 
     generator.emitExpressionInfo(divot(), divotStart(), divotEnd());
 
     generator.emitExpressionInfo(divot(), divotStart(), divotEnd());

-    return generator.emitDeleteByVal(generator.finalDestination(dst), r0.get(), r1);
+    if (m_base->isSuperNode())
+        return emitThrowReferenceError(generator, "Cannot delete a super property");
+    return generator.emitDeleteByVal(generator.finalDestination(dst), r0.get(), r1.get());

 }
 
 // ------------------------------ DeleteDotNode -----------------------------------
 
 RegisterID* DeleteDotNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
 {
 }
 
 // ------------------------------ DeleteDotNode -----------------------------------
 
 RegisterID* DeleteDotNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
 {

-    RegisterID* r0 = generator.emitNode(m_base);
+    RefPtr<RegisterID> r0 = generator.emitNode(m_base);

 
     generator.emitExpressionInfo(divot(), divotStart(), divotEnd());
 
     generator.emitExpressionInfo(divot(), divotStart(), divotEnd());

-    return generator.emitDeleteById(generator.finalDestination(dst), r0, m_ident);
+    if (m_base->isSuperNode())
+        return emitThrowReferenceError(generator, "Cannot delete a super property");
+    return generator.emitDeleteById(generator.finalDestination(dst), r0.get(), m_ident);

 }
 
 // ------------------------------ DeleteValueNode -----------------------------------
 }
 
 // ------------------------------ DeleteValueNode -----------------------------------


@@ -873,18 +1215,19 @@ RegisterID* VoidNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst
     return generator.emitLoad(dst, jsUndefined());
 }
 
     return generator.emitLoad(dst, jsUndefined());
 }
 

-// ------------------------------ TypeOfValueNode -----------------------------------
+// ------------------------------ TypeOfResolveNode -----------------------------------

 
 RegisterID* TypeOfResolveNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
 {
 
 RegisterID* TypeOfResolveNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
 {

-    if (Local local = generator.local(m_ident)) {
+    Variable var = generator.variable(m_ident);
+    if (RegisterID* local = var.local()) {

         if (dst == generator.ignoredResult())
             return 0;
         if (dst == generator.ignoredResult())
             return 0;

-        return generator.emitTypeOf(generator.finalDestination(dst), local.get());
+        return generator.emitTypeOf(generator.finalDestination(dst), local);

     }
 
     }
 

-    RefPtr<RegisterID> scope = generator.emitResolveScope(generator.tempDestination(dst), m_ident);
-    RefPtr<RegisterID> value = generator.emitGetFromScope(generator.newTemporary(), scope.get(), m_ident, DoNotThrowIfNotFound);
+    RefPtr<RegisterID> scope = generator.emitResolveScope(dst, var);
+    RefPtr<RegisterID> value = generator.emitGetFromScope(generator.newTemporary(), scope.get(), var, DoNotThrowIfNotFound);

     if (dst == generator.ignoredResult())
         return 0;
     return generator.emitTypeOf(generator.finalDestination(dst, scope.get()), value.get());
     if (dst == generator.ignoredResult())
         return 0;
     return generator.emitTypeOf(generator.finalDestination(dst, scope.get()), value.get());


@@ -910,27 +1253,34 @@ RegisterID* PrefixNode::emitResolve(BytecodeGenerator& generator, RegisterID* ds
     ResolveNode* resolve = static_cast<ResolveNode*>(m_expr);
     const Identifier& ident = resolve->identifier();
 
     ResolveNode* resolve = static_cast<ResolveNode*>(m_expr);
     const Identifier& ident = resolve->identifier();
 

-    if (Local local = generator.local(ident)) {
-        RegisterID* localReg = local.get();
-        if (local.isReadOnly()) {
+    Variable var = generator.variable(ident);
+    if (RegisterID* local = var.local()) {
+        RefPtr<RegisterID> localReg = local;
+        if (var.isReadOnly()) {

             generator.emitReadOnlyExceptionIfNeeded();
             generator.emitReadOnlyExceptionIfNeeded();

-            localReg = generator.emitMove(generator.tempDestination(dst), localReg);
-        } else if (local.isCaptured()) {
+            localReg = generator.emitMove(generator.tempDestination(dst), localReg.get());
+        } else if (generator.vm()->typeProfiler()) {

             RefPtr<RegisterID> tempDst = generator.tempDestination(dst);
             RefPtr<RegisterID> tempDst = generator.tempDestination(dst);

-            generator.emitMove(tempDst.get(), localReg);
+            generator.emitMove(tempDst.get(), localReg.get());

             emitIncOrDec(generator, tempDst.get(), m_operator);
             emitIncOrDec(generator, tempDst.get(), m_operator);

-            generator.emitMove(localReg, tempDst.get());
+            generator.emitMove(localReg.get(), tempDst.get());
+            if (generator.vm()->typeProfiler())
+                generator.emitTypeProfilerExpressionInfo(divotStart(), divotEnd());

             return generator.moveToDestinationIfNeeded(dst, tempDst.get());
         }
             return generator.moveToDestinationIfNeeded(dst, tempDst.get());
         }

-        emitIncOrDec(generator, localReg, m_operator);
-        return generator.moveToDestinationIfNeeded(dst, localReg);
+        emitIncOrDec(generator, localReg.get(), m_operator);
+        return generator.moveToDestinationIfNeeded(dst, localReg.get());

     }
 
     generator.emitExpressionInfo(divot(), divotStart(), divotEnd());
     }
 
     generator.emitExpressionInfo(divot(), divotStart(), divotEnd());

-    RefPtr<RegisterID> scope = generator.emitResolveScope(generator.tempDestination(dst), ident);
-    RefPtr<RegisterID> value = generator.emitGetFromScope(generator.newTemporary(), scope.get(), ident, ThrowIfNotFound);
+    RefPtr<RegisterID> scope = generator.emitResolveScope(dst, var);
+    RefPtr<RegisterID> value = generator.emitGetFromScope(generator.newTemporary(), scope.get(), var, ThrowIfNotFound);

     emitIncOrDec(generator, value.get(), m_operator);
     emitIncOrDec(generator, value.get(), m_operator);

-    generator.emitPutToScope(scope.get(), ident, value.get(), ThrowIfNotFound);
+    generator.emitPutToScope(scope.get(), var, value.get(), ThrowIfNotFound);
+    if (generator.vm()->typeProfiler()) {
+        generator.emitProfileType(value.get(), var.isResolved() ? ProfileTypeBytecodePutToLocalScope : ProfileTypeBytecodePutToScope, &ident);
+        generator.emitTypeProfilerExpressionInfo(divotStart(), divotEnd());
+    }

     return generator.moveToDestinationIfNeeded(dst, value.get());
 }
 
     return generator.moveToDestinationIfNeeded(dst, value.get());
 }
 


@@ -950,6 +1300,10 @@ RegisterID* PrefixNode::emitBracket(BytecodeGenerator& generator, RegisterID* ds
     emitIncOrDec(generator, value, m_operator);
     generator.emitExpressionInfo(divot(), divotStart(), divotEnd());
     generator.emitPutByVal(base.get(), property.get(), value);
     emitIncOrDec(generator, value, m_operator);
     generator.emitExpressionInfo(divot(), divotStart(), divotEnd());
     generator.emitPutByVal(base.get(), property.get(), value);

+    if (generator.vm()->typeProfiler()) {
+        generator.emitProfileType(value, ProfileTypeBytecodeDoesNotHaveGlobalID, nullptr);
+        generator.emitTypeProfilerExpressionInfo(divotStart(), divotEnd());
+    }

     return generator.moveToDestinationIfNeeded(dst, propDst.get());
 }
 
     return generator.moveToDestinationIfNeeded(dst, propDst.get());
 }
 


@@ -968,6 +1322,10 @@ RegisterID* PrefixNode::emitDot(BytecodeGenerator& generator, RegisterID* dst)
     emitIncOrDec(generator, value, m_operator);
     generator.emitExpressionInfo(divot(), divotStart(), divotEnd());
     generator.emitPutById(base.get(), ident, value);
     emitIncOrDec(generator, value, m_operator);
     generator.emitExpressionInfo(divot(), divotStart(), divotEnd());
     generator.emitPutById(base.get(), ident, value);

+    if (generator.vm()->typeProfiler()) {
+        generator.emitProfileType(value, ProfileTypeBytecodeDoesNotHaveGlobalID, nullptr);
+        generator.emitTypeProfilerExpressionInfo(divotStart(), divotEnd());
+    }

     return generator.moveToDestinationIfNeeded(dst, propDst.get());
 }
 
     return generator.moveToDestinationIfNeeded(dst, propDst.get());
 }
 


@@ -983,17 +1341,17 @@ RegisterID* PrefixNode::emitBytecode(BytecodeGenerator& generator, RegisterID* d
         return emitDot(generator, dst);
 
     return emitThrowReferenceError(generator, m_operator == OpPlusPlus
         return emitDot(generator, dst);
 
     return emitThrowReferenceError(generator, m_operator == OpPlusPlus

-        ? "Prefix ++ operator applied to value that is not a reference."
-        : "Prefix -- operator applied to value that is not a reference.");
+        ? ASCIILiteral("Prefix ++ operator applied to value that is not a reference.")
+        : ASCIILiteral("Prefix -- operator applied to value that is not a reference."));

 }
 
 // ------------------------------ Unary Operation Nodes -----------------------------------
 
 RegisterID* UnaryOpNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
 {
 }
 
 // ------------------------------ Unary Operation Nodes -----------------------------------
 
 RegisterID* UnaryOpNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
 {

-    RegisterID* src = generator.emitNode(m_expr);
+    RefPtr<RegisterID> src = generator.emitNode(m_expr);

     generator.emitExpressionInfo(position(), position(), position());
     generator.emitExpressionInfo(position(), position(), position());

-    return generator.emitUnaryOp(opcodeID(), generator.finalDestination(dst), src);
+    return generator.emitUnaryOp(opcodeID(), generator.finalDestination(dst), src.get());

 }
 
 // ------------------------------ BitwiseNotNode -----------------------------------
 }
 
 // ------------------------------ BitwiseNotNode -----------------------------------


@@ -1001,8 +1359,8 @@ RegisterID* UnaryOpNode::emitBytecode(BytecodeGenerator& generator, RegisterID*
 RegisterID* BitwiseNotNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
 {
     RefPtr<RegisterID> src2 = generator.emitLoad(generator.newTemporary(), jsNumber(-1));
 RegisterID* BitwiseNotNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
 {
     RefPtr<RegisterID> src2 = generator.emitLoad(generator.newTemporary(), jsNumber(-1));

-    RegisterID* src1 = generator.emitNode(m_expr);
-    return generator.emitBinaryOp(op_bitxor, generator.finalDestination(dst, src1), src1, src2.get(), OperandTypes(m_expr->resultDescriptor(), ResultType::numberTypeIsInt32()));
+    RefPtr<RegisterID> src1 = generator.emitNode(m_expr);
+    return generator.emitBinaryOp(op_bitxor, generator.finalDestination(dst, src1.get()), src1.get(), src2.get(), OperandTypes(m_expr->resultDescriptor(), ResultType::numberTypeIsInt32()));

 }
  
 // ------------------------------ LogicalNotNode -----------------------------------
 }
  
 // ------------------------------ LogicalNotNode -----------------------------------


@@ -1216,20 +1574,20 @@ RegisterID* BinaryOpNode::emitBytecode(BytecodeGenerator& generator, RegisterID*
     }
 
     RefPtr<RegisterID> src1 = generator.emitNodeForLeftHandSide(left, m_rightHasAssignments, right->isPure(generator));
     }
 
     RefPtr<RegisterID> src1 = generator.emitNodeForLeftHandSide(left, m_rightHasAssignments, right->isPure(generator));

-    bool wasTypeof = generator.m_lastOpcodeID == op_typeof;
-    RegisterID* src2 = generator.emitNode(right);
+    bool wasTypeof = generator.lastOpcodeID() == op_typeof;
+    RefPtr<RegisterID> src2 = generator.emitNode(right);

     generator.emitExpressionInfo(position(), position(), position());
     if (wasTypeof && (opcodeID == op_neq || opcodeID == op_nstricteq)) {
         RefPtr<RegisterID> tmp = generator.tempDestination(dst);
         if (opcodeID == op_neq)
     generator.emitExpressionInfo(position(), position(), position());
     if (wasTypeof && (opcodeID == op_neq || opcodeID == op_nstricteq)) {
         RefPtr<RegisterID> tmp = generator.tempDestination(dst);
         if (opcodeID == op_neq)

-            generator.emitEqualityOp(op_eq, generator.finalDestination(tmp.get(), src1.get()), src1.get(), src2);
+            generator.emitEqualityOp(op_eq, generator.finalDestination(tmp.get(), src1.get()), src1.get(), src2.get());

         else if (opcodeID == op_nstricteq)
         else if (opcodeID == op_nstricteq)

-            generator.emitEqualityOp(op_stricteq, generator.finalDestination(tmp.get(), src1.get()), src1.get(), src2);
+            generator.emitEqualityOp(op_stricteq, generator.finalDestination(tmp.get(), src1.get()), src1.get(), src2.get());

         else
             RELEASE_ASSERT_NOT_REACHED();
         return generator.emitUnaryOp(op_not, generator.finalDestination(dst, tmp.get()), tmp.get());
     }
         else
             RELEASE_ASSERT_NOT_REACHED();
         return generator.emitUnaryOp(op_not, generator.finalDestination(dst, tmp.get()), tmp.get());
     }

-    RegisterID* result = generator.emitBinaryOp(opcodeID, generator.finalDestination(dst, src1.get()), src1.get(), src2, OperandTypes(left->resultDescriptor(), right->resultDescriptor()));
+    RegisterID* result = generator.emitBinaryOp(opcodeID, generator.finalDestination(dst, src1.get()), src1.get(), src2.get(), OperandTypes(left->resultDescriptor(), right->resultDescriptor()));

     if (opcodeID == op_urshift && dst != generator.ignoredResult())
         return generator.emitUnaryOp(op_unsigned, result, result);
     return result;
     if (opcodeID == op_urshift && dst != generator.ignoredResult())
         return generator.emitUnaryOp(op_unsigned, result, result);
     return result;


@@ -1249,8 +1607,8 @@ RegisterID* EqualNode::emitBytecode(BytecodeGenerator& generator, RegisterID* ds
         std::swap(left, right);
 
     RefPtr<RegisterID> src1 = generator.emitNodeForLeftHandSide(left, m_rightHasAssignments, m_expr2->isPure(generator));
         std::swap(left, right);
 
     RefPtr<RegisterID> src1 = generator.emitNodeForLeftHandSide(left, m_rightHasAssignments, m_expr2->isPure(generator));

-    RegisterID* src2 = generator.emitNode(right);
-    return generator.emitEqualityOp(op_eq, generator.finalDestination(dst, src1.get()), src1.get(), src2);
+    RefPtr<RegisterID> src2 = generator.emitNode(right);
+    return generator.emitEqualityOp(op_eq, generator.finalDestination(dst, src1.get()), src1.get(), src2.get());

 }
 
 RegisterID* StrictEqualNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
 }
 
 RegisterID* StrictEqualNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)


@@ -1261,16 +1619,16 @@ RegisterID* StrictEqualNode::emitBytecode(BytecodeGenerator& generator, Register
         std::swap(left, right);
 
     RefPtr<RegisterID> src1 = generator.emitNodeForLeftHandSide(left, m_rightHasAssignments, m_expr2->isPure(generator));
         std::swap(left, right);
 
     RefPtr<RegisterID> src1 = generator.emitNodeForLeftHandSide(left, m_rightHasAssignments, m_expr2->isPure(generator));

-    RegisterID* src2 = generator.emitNode(right);
-    return generator.emitEqualityOp(op_stricteq, generator.finalDestination(dst, src1.get()), src1.get(), src2);
+    RefPtr<RegisterID> src2 = generator.emitNode(right);
+    return generator.emitEqualityOp(op_stricteq, generator.finalDestination(dst, src1.get()), src1.get(), src2.get());

 }
 
 RegisterID* ThrowableBinaryOpNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
 {
     RefPtr<RegisterID> src1 = generator.emitNodeForLeftHandSide(m_expr1, m_rightHasAssignments, m_expr2->isPure(generator));
 }
 
 RegisterID* ThrowableBinaryOpNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
 {
     RefPtr<RegisterID> src1 = generator.emitNodeForLeftHandSide(m_expr1, m_rightHasAssignments, m_expr2->isPure(generator));

-    RegisterID* src2 = generator.emitNode(m_expr2);
+    RefPtr<RegisterID> src2 = generator.emitNode(m_expr2);

     generator.emitExpressionInfo(divot(), divotStart(), divotEnd());
     generator.emitExpressionInfo(divot(), divotStart(), divotEnd());

-    return generator.emitBinaryOp(opcodeID(), generator.finalDestination(dst, src1.get()), src1.get(), src2, OperandTypes(m_expr1->resultDescriptor(), m_expr2->resultDescriptor()));
+    return generator.emitBinaryOp(opcodeID(), generator.finalDestination(dst, src1.get()), src1.get(), src2.get(), OperandTypes(m_expr1->resultDescriptor(), m_expr2->resultDescriptor()));

 }
 
 RegisterID* InstanceOfNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
 }
 
 RegisterID* InstanceOfNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)


@@ -1335,14 +1693,18 @@ RegisterID* ConditionalNode::emitBytecode(BytecodeGenerator& generator, Register
     generator.emitNodeInConditionContext(m_logical, beforeThen.get(), beforeElse.get(), FallThroughMeansTrue);
     generator.emitLabel(beforeThen.get());
 
     generator.emitNodeInConditionContext(m_logical, beforeThen.get(), beforeElse.get(), FallThroughMeansTrue);
     generator.emitLabel(beforeThen.get());
 

+    generator.emitProfileControlFlow(m_expr1->startOffset());

     generator.emitNode(newDst.get(), m_expr1);
     generator.emitJump(afterElse.get());
 
     generator.emitLabel(beforeElse.get());
     generator.emitNode(newDst.get(), m_expr1);
     generator.emitJump(afterElse.get());
 
     generator.emitLabel(beforeElse.get());

+    generator.emitProfileControlFlow(m_expr1->endOffset() + 1);

     generator.emitNode(newDst.get(), m_expr2);
 
     generator.emitLabel(afterElse.get());
 
     generator.emitNode(newDst.get(), m_expr2);
 
     generator.emitLabel(afterElse.get());
 

+    generator.emitProfileControlFlow(m_expr2->endOffset() + 1);
+

     return newDst.get();
 }
 
     return newDst.get();
 }
 


@@ -1407,60 +1769,80 @@ static ALWAYS_INLINE RegisterID* emitReadModifyAssignment(BytecodeGenerator& gen
 
 RegisterID* ReadModifyResolveNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
 {
 
 RegisterID* ReadModifyResolveNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
 {

-    if (Local local = generator.local(m_ident)) {
-        if (local.isReadOnly()) {
+    JSTextPosition newDivot = divotStart() + m_ident.length();
+    Variable var = generator.variable(m_ident);
+    if (RegisterID* local = var.local()) {
+        if (var.isReadOnly()) {

             generator.emitReadOnlyExceptionIfNeeded();
             generator.emitReadOnlyExceptionIfNeeded();

-            return emitReadModifyAssignment(generator, generator.finalDestination(dst), local.get(), m_right, m_operator, OperandTypes(ResultType::unknownType(), m_right->resultDescriptor()));
+            return emitReadModifyAssignment(generator, generator.finalDestination(dst), local, m_right, m_operator, OperandTypes(ResultType::unknownType(), m_right->resultDescriptor()));

         }
         
         }
         

-        if (local.isCaptured()
+        if (generator.vm()->typeProfiler()

             || generator.leftHandSideNeedsCopy(m_rightHasAssignments, m_right->isPure(generator))) {
             RefPtr<RegisterID> result = generator.newTemporary();
             || generator.leftHandSideNeedsCopy(m_rightHasAssignments, m_right->isPure(generator))) {
             RefPtr<RegisterID> result = generator.newTemporary();

-            generator.emitMove(result.get(), local.get());
+            generator.emitMove(result.get(), local);

             emitReadModifyAssignment(generator, result.get(), result.get(), m_right, m_operator, OperandTypes(ResultType::unknownType(), m_right->resultDescriptor()));
             emitReadModifyAssignment(generator, result.get(), result.get(), m_right, m_operator, OperandTypes(ResultType::unknownType(), m_right->resultDescriptor()));

-            generator.emitMove(local.get(), result.get());
+            generator.emitMove(local, result.get());
+            generator.invalidateForInContextForLocal(local);
+            if (generator.vm()->typeProfiler())
+                generator.emitTypeProfilerExpressionInfo(divotStart(), divotEnd());

             return generator.moveToDestinationIfNeeded(dst, result.get());
         }
         
             return generator.moveToDestinationIfNeeded(dst, result.get());
         }
         

-        RegisterID* result = emitReadModifyAssignment(generator, local.get(), local.get(), m_right, m_operator, OperandTypes(ResultType::unknownType(), m_right->resultDescriptor()));
+        RegisterID* result = emitReadModifyAssignment(generator, local, local, m_right, m_operator, OperandTypes(ResultType::unknownType(), m_right->resultDescriptor()));
+        generator.invalidateForInContextForLocal(local);

         return generator.moveToDestinationIfNeeded(dst, result);
     }
 
         return generator.moveToDestinationIfNeeded(dst, result);
     }
 

-    JSTextPosition newDivot = divotStart() + m_ident.length();

     generator.emitExpressionInfo(newDivot, divotStart(), newDivot);
     generator.emitExpressionInfo(newDivot, divotStart(), newDivot);

-    RefPtr<RegisterID> scope = generator.emitResolveScope(generator.newTemporary(), m_ident);
-    RefPtr<RegisterID> value = generator.emitGetFromScope(generator.newTemporary(), scope.get(), m_ident, ThrowIfNotFound);
+    RefPtr<RegisterID> scope = generator.emitResolveScope(nullptr, var);
+    RefPtr<RegisterID> value = generator.emitGetFromScope(generator.newTemporary(), scope.get(), var, ThrowIfNotFound);

     RefPtr<RegisterID> result = emitReadModifyAssignment(generator, generator.finalDestination(dst, value.get()), value.get(), m_right, m_operator, OperandTypes(ResultType::unknownType(), m_right->resultDescriptor()), this);
     RefPtr<RegisterID> result = emitReadModifyAssignment(generator, generator.finalDestination(dst, value.get()), value.get(), m_right, m_operator, OperandTypes(ResultType::unknownType(), m_right->resultDescriptor()), this);

-    return generator.emitPutToScope(scope.get(), m_ident, result.get(), ThrowIfNotFound);
+    RegisterID* returnResult = generator.emitPutToScope(scope.get(), var, result.get(), ThrowIfNotFound);
+    if (generator.vm()->typeProfiler()) {
+        generator.emitProfileType(result.get(), var.isResolved() ? ProfileTypeBytecodePutToLocalScope : ProfileTypeBytecodePutToScope, &m_ident);
+        generator.emitTypeProfilerExpressionInfo(divotStart(), divotEnd());
+    }
+    return returnResult;

 }
 
 // ------------------------------ AssignResolveNode -----------------------------------
 
 RegisterID* AssignResolveNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
 {
 }
 
 // ------------------------------ AssignResolveNode -----------------------------------
 
 RegisterID* AssignResolveNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
 {

-    if (Local local = generator.local(m_ident)) {
-        if (local.isReadOnly()) {
+    Variable var = generator.variable(m_ident);
+    if (RegisterID* local = var.local()) {
+        if (var.isReadOnly()) {

             generator.emitReadOnlyExceptionIfNeeded();
             return generator.emitNode(dst, m_right);
         }
             generator.emitReadOnlyExceptionIfNeeded();
             return generator.emitNode(dst, m_right);
         }

-        if (local.isCaptured()) {
+        if (var.isSpecial() || generator.vm()->typeProfiler()) {

             RefPtr<RegisterID> tempDst = generator.tempDestination(dst);
             generator.emitNode(tempDst.get(), m_right);
             RefPtr<RegisterID> tempDst = generator.tempDestination(dst);
             generator.emitNode(tempDst.get(), m_right);

-            generator.emitMove(local.get(), tempDst.get());
+            generator.emitMove(local, tempDst.get());
+            generator.invalidateForInContextForLocal(local);
+            if (generator.vm()->typeProfiler())
+                generator.emitTypeProfilerExpressionInfo(divotStart(), divotEnd());

             return generator.moveToDestinationIfNeeded(dst, tempDst.get());
         }
             return generator.moveToDestinationIfNeeded(dst, tempDst.get());
         }

-        RegisterID* result = generator.emitNode(local.get(), m_right);
+        RegisterID* result = generator.emitNode(local, m_right);
+        generator.invalidateForInContextForLocal(local);

         return generator.moveToDestinationIfNeeded(dst, result);
     }
 
     if (generator.isStrictMode())
         generator.emitExpressionInfo(divot(), divotStart(), divotEnd());
         return generator.moveToDestinationIfNeeded(dst, result);
     }
 
     if (generator.isStrictMode())
         generator.emitExpressionInfo(divot(), divotStart(), divotEnd());

-    RefPtr<RegisterID> scope = generator.emitResolveScope(generator.newTemporary(), m_ident);
+    RefPtr<RegisterID> scope = generator.emitResolveScope(nullptr, var);

     if (dst == generator.ignoredResult())
         dst = 0;
     RefPtr<RegisterID> result = generator.emitNode(dst, m_right);
     generator.emitExpressionInfo(divot(), divotStart(), divotEnd());
     if (dst == generator.ignoredResult())
         dst = 0;
     RefPtr<RegisterID> result = generator.emitNode(dst, m_right);
     generator.emitExpressionInfo(divot(), divotStart(), divotEnd());

-    return generator.emitPutToScope(scope.get(), m_ident, result.get(), generator.isStrictMode() ? ThrowIfNotFound : DoNotThrowIfNotFound);
+    RegisterID* returnResult = generator.emitPutToScope(scope.get(), var, result.get(), generator.isStrictMode() ? ThrowIfNotFound : DoNotThrowIfNotFound);
+    if (generator.vm()->typeProfiler()) {
+        generator.emitProfileType(result.get(), var.isResolved() ? ProfileTypeBytecodePutToLocalScope : ProfileTypeBytecodePutToScope, &m_ident);
+        generator.emitTypeProfilerExpressionInfo(divotStart(), divotEnd());
+    } 
+    return returnResult;

 }
 
 // ------------------------------ AssignDotNode -----------------------------------
 }
 
 // ------------------------------ AssignDotNode -----------------------------------


@@ -1469,10 +1851,14 @@ RegisterID* AssignDotNode::emitBytecode(BytecodeGenerator& generator, RegisterID
 {
     RefPtr<RegisterID> base = generator.emitNodeForLeftHandSide(m_base, m_rightHasAssignments, m_right->isPure(generator));
     RefPtr<RegisterID> value = generator.destinationForAssignResult(dst);
 {
     RefPtr<RegisterID> base = generator.emitNodeForLeftHandSide(m_base, m_rightHasAssignments, m_right->isPure(generator));
     RefPtr<RegisterID> value = generator.destinationForAssignResult(dst);

-    RegisterID* result = generator.emitNode(value.get(), m_right);
+    RefPtr<RegisterID> result = generator.emitNode(value.get(), m_right);

     generator.emitExpressionInfo(divot(), divotStart(), divotEnd());
     generator.emitExpressionInfo(divot(), divotStart(), divotEnd());

-    RegisterID* forwardResult = (dst == generator.ignoredResult()) ? result : generator.moveToDestinationIfNeeded(generator.tempDestination(result), result);
+    RegisterID* forwardResult = (dst == generator.ignoredResult()) ? result.get() : generator.moveToDestinationIfNeeded(generator.tempDestination(result.get()), result.get());

     generator.emitPutById(base.get(), m_ident, forwardResult);
     generator.emitPutById(base.get(), m_ident, forwardResult);

+    if (generator.vm()->typeProfiler()) {
+        generator.emitProfileType(forwardResult, ProfileTypeBytecodeDoesNotHaveGlobalID, nullptr);
+        generator.emitTypeProfilerExpressionInfo(divotStart(), divotEnd());
+    }

     return generator.moveToDestinationIfNeeded(dst, forwardResult);
 }
 
     return generator.moveToDestinationIfNeeded(dst, forwardResult);
 }
 


@@ -1487,14 +1873,19 @@ RegisterID* ReadModifyDotNode::emitBytecode(BytecodeGenerator& generator, Regist
     RegisterID* updatedValue = emitReadModifyAssignment(generator, generator.finalDestination(dst, value.get()), value.get(), m_right, static_cast<JSC::Operator>(m_operator), OperandTypes(ResultType::unknownType(), m_right->resultDescriptor()));
 
     generator.emitExpressionInfo(divot(), divotStart(), divotEnd());
     RegisterID* updatedValue = emitReadModifyAssignment(generator, generator.finalDestination(dst, value.get()), value.get(), m_right, static_cast<JSC::Operator>(m_operator), OperandTypes(ResultType::unknownType(), m_right->resultDescriptor()));
 
     generator.emitExpressionInfo(divot(), divotStart(), divotEnd());

-    return generator.emitPutById(base.get(), m_ident, updatedValue);
+    RegisterID* ret = generator.emitPutById(base.get(), m_ident, updatedValue);
+    if (generator.vm()->typeProfiler()) {
+        generator.emitProfileType(updatedValue, ProfileTypeBytecodeDoesNotHaveGlobalID, nullptr);
+        generator.emitTypeProfilerExpressionInfo(divotStart(), divotEnd());
+    }
+    return ret;

 }
 
 // ------------------------------ AssignErrorNode -----------------------------------
 
 RegisterID* AssignErrorNode::emitBytecode(BytecodeGenerator& generator, RegisterID*)
 {
 }
 
 // ------------------------------ AssignErrorNode -----------------------------------
 
 RegisterID* AssignErrorNode::emitBytecode(BytecodeGenerator& generator, RegisterID*)
 {

-    return emitThrowReferenceError(generator, "Left side of assignment is not a reference.");
+    return emitThrowReferenceError(generator, ASCIILiteral("Left side of assignment is not a reference."));

 }
 
 // ------------------------------ AssignBracketNode -----------------------------------
 }
 
 // ------------------------------ AssignBracketNode -----------------------------------


@@ -1504,11 +1895,20 @@ RegisterID* AssignBracketNode::emitBytecode(BytecodeGenerator& generator, Regist
     RefPtr<RegisterID> base = generator.emitNodeForLeftHandSide(m_base, m_subscriptHasAssignments || m_rightHasAssignments, m_subscript->isPure(generator) && m_right->isPure(generator));
     RefPtr<RegisterID> property = generator.emitNodeForLeftHandSide(m_subscript, m_rightHasAssignments, m_right->isPure(generator));
     RefPtr<RegisterID> value = generator.destinationForAssignResult(dst);
     RefPtr<RegisterID> base = generator.emitNodeForLeftHandSide(m_base, m_subscriptHasAssignments || m_rightHasAssignments, m_subscript->isPure(generator) && m_right->isPure(generator));
     RefPtr<RegisterID> property = generator.emitNodeForLeftHandSide(m_subscript, m_rightHasAssignments, m_right->isPure(generator));
     RefPtr<RegisterID> value = generator.destinationForAssignResult(dst);

-    RegisterID* result = generator.emitNode(value.get(), m_right);
+    RefPtr<RegisterID> result = generator.emitNode(value.get(), m_right);

 
     generator.emitExpressionInfo(divot(), divotStart(), divotEnd());
 
     generator.emitExpressionInfo(divot(), divotStart(), divotEnd());

-    RegisterID* forwardResult = (dst == generator.ignoredResult()) ? result : generator.moveToDestinationIfNeeded(generator.tempDestination(result), result);
-    generator.emitPutByVal(base.get(), property.get(), forwardResult);
+    RegisterID* forwardResult = (dst == generator.ignoredResult()) ? result.get() : generator.moveToDestinationIfNeeded(generator.tempDestination(result.get()), result.get());
+
+    if (m_subscript->isString())
+        generator.emitPutById(base.get(), static_cast<StringNode*>(m_subscript)->value(), forwardResult);
+    else
+        generator.emitPutByVal(base.get(), property.get(), forwardResult);
+
+    if (generator.vm()->typeProfiler()) {
+        generator.emitProfileType(forwardResult, ProfileTypeBytecodeDoesNotHaveGlobalID, nullptr);
+        generator.emitTypeProfilerExpressionInfo(divotStart(), divotEnd());
+    }

     return generator.moveToDestinationIfNeeded(dst, forwardResult);
 }
 
     return generator.moveToDestinationIfNeeded(dst, forwardResult);
 }
 


@@ -1525,6 +1925,10 @@ RegisterID* ReadModifyBracketNode::emitBytecode(BytecodeGenerator& generator, Re
 
     generator.emitExpressionInfo(divot(), divotStart(), divotEnd());
     generator.emitPutByVal(base.get(), property.get(), updatedValue);
 
     generator.emitExpressionInfo(divot(), divotStart(), divotEnd());
     generator.emitPutByVal(base.get(), property.get(), updatedValue);

+    if (generator.vm()->typeProfiler()) {
+        generator.emitProfileType(updatedValue, ProfileTypeBytecodeDoesNotHaveGlobalID, nullptr);
+        generator.emitTypeProfilerExpressionInfo(divotStart(), divotEnd());
+    }

 
     return updatedValue;
 }
 
     return updatedValue;
 }


@@ -1533,10 +1937,10 @@ RegisterID* ReadModifyBracketNode::emitBytecode(BytecodeGenerator& generator, Re
 
 RegisterID* CommaNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
 {
 
 RegisterID* CommaNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
 {

-    ASSERT(m_expressions.size() > 1);
-    for (size_t i = 0; i < m_expressions.size() - 1; i++)
-        generator.emitNode(generator.ignoredResult(), m_expressions[i]);
-    return generator.emitNode(dst, m_expressions.last());
+    CommaNode* node = this;
+    for (; node && node->next(); node = node->next())
+        generator.emitNode(generator.ignoredResult(), node->m_expr);
+    return generator.emitNode(dst, node->m_expr);

 }
 
 // ------------------------------ ConstDeclNode ------------------------------------
 }
 
 // ------------------------------ ConstDeclNode ------------------------------------


@@ -1544,17 +1948,19 @@ RegisterID* CommaNode::emitBytecode(BytecodeGenerator& generator, RegisterID* ds
 RegisterID* ConstDeclNode::emitCodeSingle(BytecodeGenerator& generator)
 {
     // FIXME: This code does not match the behavior of const in Firefox.
 RegisterID* ConstDeclNode::emitCodeSingle(BytecodeGenerator& generator)
 {
     // FIXME: This code does not match the behavior of const in Firefox.

-    if (Local local = generator.constLocal(m_ident)) {
+    Variable var = generator.variable(m_ident);
+    if (RegisterID* local = var.local()) {

         if (!m_init)
         if (!m_init)

-            return local.get();
+            return local;

 
 

-        if (local.isCaptured()) {
+        // FIXME: Maybe call emitExpressionInfo here.
+        if (var.isSpecial() || generator.vm()->typeProfiler()) {

             RefPtr<RegisterID> tempDst = generator.newTemporary();
             generator.emitNode(tempDst.get(), m_init);
             RefPtr<RegisterID> tempDst = generator.newTemporary();
             generator.emitNode(tempDst.get(), m_init);

-            return generator.emitMove(local.get(), tempDst.get());
+            return generator.emitMove(local, tempDst.get());

         }
         
         }
         

-        return generator.emitNode(local.get(), m_init);
+        return generator.emitNode(local, m_init);

     }
 
     RefPtr<RegisterID> value = m_init ? generator.emitNode(m_init) : generator.emitLoad(0, jsUndefined());
     }
 
     RefPtr<RegisterID> value = m_init ? generator.emitNode(m_init) : generator.emitLoad(0, jsUndefined());


@@ -1562,12 +1968,24 @@ RegisterID* ConstDeclNode::emitCodeSingle(BytecodeGenerator& generator)
     if (generator.codeType() == GlobalCode)
         return generator.emitInitGlobalConst(m_ident, value.get());
 
     if (generator.codeType() == GlobalCode)
         return generator.emitInitGlobalConst(m_ident, value.get());
 

-    if (generator.codeType() != EvalCode)
-        return value.get();
+    if (generator.codeType() != EvalCode) {
+        // Do a special kind of resolution. If anything fails, then don't perform the assignment. This is
+        // pretty shady - particularly how negligent it is with inteleaving scopes - but it's the
+        // behavior that JSC has had for a long time.
+        
+        ASSERT(generator.codeType() == FunctionCode);
+        
+        var = generator.variablePerSymbolTable(m_ident);
+        if (!var.isResolved())
+            return value.get();
+        
+        RefPtr<RegisterID> scope = generator.emitResolveScope(generator.newTemporary(), var);
+        return generator.emitPutToScope(scope.get(), var, value.get(), DoNotThrowIfNotFound);
+    }

 
     // FIXME: This will result in incorrect assignment if m_ident exists in an intervening with scope.
 
     // FIXME: This will result in incorrect assignment if m_ident exists in an intervening with scope.

-    RefPtr<RegisterID> scope = generator.emitResolveScope(generator.newTemporary(), m_ident);
-    return generator.emitPutToScope(scope.get(), m_ident, value.get(), DoNotThrowIfNotFound);
+    RefPtr<RegisterID> scope = generator.emitResolveScope(nullptr, var);
+    return generator.emitPutToScope(scope.get(), var, value.get(), DoNotThrowIfNotFound);

 }
 
 RegisterID* ConstDeclNode::emitBytecode(BytecodeGenerator& generator, RegisterID*)
 }
 
 RegisterID* ConstDeclNode::emitBytecode(BytecodeGenerator& generator, RegisterID*)


@@ -1592,15 +2010,13 @@ void ConstStatementNode::emitBytecode(BytecodeGenerator& generator, RegisterID*)
 
 inline StatementNode* SourceElements::lastStatement() const
 {
 
 inline StatementNode* SourceElements::lastStatement() const
 {

-    size_t size = m_statements.size();
-    return size ? m_statements[size - 1] : 0;
+    return m_tail;

 }
 
 inline void SourceElements::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
 {
 }
 
 inline void SourceElements::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
 {

-    size_t size = m_statements.size();
-    for (size_t i = 0; i < size; ++i)
-        generator.emitNode(dst, m_statements[i]);
+    for (StatementNode* statement = m_head; statement; statement = statement->next())
+        generator.emitNode(dst, statement);

 }
 
 // ------------------------------ BlockNode ------------------------------------
 }
 
 // ------------------------------ BlockNode ------------------------------------


@@ -1610,7 +2026,7 @@ inline StatementNode* BlockNode::lastStatement() const
     return m_statements ? m_statements->lastStatement() : 0;
 }
 
     return m_statements ? m_statements->lastStatement() : 0;
 }
 

-inline StatementNode* BlockNode::singleStatement() const
+StatementNode* BlockNode::singleStatement() const

 {
     return m_statements ? m_statements->singleStatement() : 0;
 }
 {
     return m_statements ? m_statements->singleStatement() : 0;
 }


@@ -1654,6 +2070,28 @@ void VarStatementNode::emitBytecode(BytecodeGenerator& generator, RegisterID*)
     generator.emitNode(m_expr);
 }
 
     generator.emitNode(m_expr);
 }
 

+// ------------------------------ EmptyVarExpression ----------------------------
+
+RegisterID* EmptyVarExpression::emitBytecode(BytecodeGenerator& generator, RegisterID*)
+{
+    if (!generator.vm()->typeProfiler())
+        return nullptr;
+
+    Variable var = generator.variable(m_ident);
+    if (RegisterID* local = var.local())
+        generator.emitProfileType(local, ProfileTypeBytecodeHasGlobalID, nullptr);
+    else {
+        RefPtr<RegisterID> scope = generator.emitResolveScope(nullptr, var);
+        RefPtr<RegisterID> value = generator.emitGetFromScope(generator.newTemporary(), scope.get(), var, DoNotThrowIfNotFound);
+        generator.emitProfileType(value.get(), var.isResolved() ? ProfileTypeBytecodeGetFromLocalScope : ProfileTypeBytecodeGetFromScope, &m_ident);
+    }
+
+    generator.emitTypeProfilerExpressionInfo(position(), JSTextPosition(-1, position().offset + m_ident.length(), -1));
+
+    // It's safe to return null here because this node will always be a child node of VarStatementNode which ignores our return value.
+    return nullptr;
+}
+

 // ------------------------------ IfElseNode ---------------------------------------
 
 static inline StatementNode* singleStatement(StatementNode* statementNode)
 // ------------------------------ IfElseNode ---------------------------------------
 
 static inline StatementNode* singleStatement(StatementNode* statementNode)


@@ -1708,6 +2146,7 @@ void IfElseNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
 
     generator.emitNodeInConditionContext(m_condition, trueTarget, falseTarget, fallThroughMode);
     generator.emitLabel(beforeThen.get());
 
     generator.emitNodeInConditionContext(m_condition, trueTarget, falseTarget, fallThroughMode);
     generator.emitLabel(beforeThen.get());

+    generator.emitProfileControlFlow(m_ifBlock->startOffset());

 
     if (!didFoldIfBlock) {
         generator.emitNode(dst, m_ifBlock);
 
     if (!didFoldIfBlock) {
         generator.emitNode(dst, m_ifBlock);


@@ -1717,10 +2156,14 @@ void IfElseNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
 
     generator.emitLabel(beforeElse.get());
 
 
     generator.emitLabel(beforeElse.get());
 

-    if (m_elseBlock)
+    if (m_elseBlock) {
+        generator.emitProfileControlFlow(m_ifBlock->endOffset() + (m_ifBlock->isBlock() ? 1 : 0));

         generator.emitNode(dst, m_elseBlock);
         generator.emitNode(dst, m_elseBlock);

+    }

 
     generator.emitLabel(afterElse.get());
 
     generator.emitLabel(afterElse.get());

+    StatementNode* endingBlock = m_elseBlock ? m_elseBlock : m_ifBlock;
+    generator.emitProfileControlFlow(endingBlock->endOffset() + (endingBlock->isBlock() ? 1 : 0));

 }
 
 // ------------------------------ DoWhileNode ----------------------------------
 }
 
 // ------------------------------ DoWhileNode ----------------------------------


@@ -1750,12 +2193,13 @@ void WhileNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
     LabelScopePtr scope = generator.newLabelScope(LabelScope::Loop);
     RefPtr<Label> topOfLoop = generator.newLabel();
 
     LabelScopePtr scope = generator.newLabelScope(LabelScope::Loop);
     RefPtr<Label> topOfLoop = generator.newLabel();
 

-    generator.emitDebugHook(WillExecuteStatement, m_expr->lineNo(), m_expr->startOffset(), m_expr->lineStartOffset());
+    generator.emitDebugHook(WillExecuteStatement, m_expr->firstLine(), m_expr->startOffset(), m_expr->lineStartOffset());

     generator.emitNodeInConditionContext(m_expr, topOfLoop.get(), scope->breakTarget(), FallThroughMeansTrue);
 
     generator.emitLabel(topOfLoop.get());
     generator.emitLoopHint();
     
     generator.emitNodeInConditionContext(m_expr, topOfLoop.get(), scope->breakTarget(), FallThroughMeansTrue);
 
     generator.emitLabel(topOfLoop.get());
     generator.emitLoopHint();
     

+    generator.emitProfileControlFlow(m_statement->startOffset());

     generator.emitNode(dst, m_statement);
 
     generator.emitLabel(scope->continueTarget());
     generator.emitNode(dst, m_statement);
 
     generator.emitLabel(scope->continueTarget());


@@ -1764,6 +2208,8 @@ void WhileNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
     generator.emitNodeInConditionContext(m_expr, topOfLoop.get(), scope->breakTarget(), FallThroughMeansFalse);
 
     generator.emitLabel(scope->breakTarget());
     generator.emitNodeInConditionContext(m_expr, topOfLoop.get(), scope->breakTarget(), FallThroughMeansFalse);
 
     generator.emitLabel(scope->breakTarget());

+
+    generator.emitProfileControlFlow(m_statement->endOffset() + (m_statement->isBlock() ? 1 : 0));

 }
 
 // ------------------------------ ForNode --------------------------------------
 }
 
 // ------------------------------ ForNode --------------------------------------


@@ -1783,6 +2229,7 @@ void ForNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
 
     generator.emitLabel(topOfLoop.get());
     generator.emitLoopHint();
 
     generator.emitLabel(topOfLoop.get());
     generator.emitLoopHint();

+    generator.emitProfileControlFlow(m_statement->startOffset());

 
     generator.emitNode(dst, m_statement);
 
 
     generator.emitNode(dst, m_statement);
 


@@ -1797,131 +2244,275 @@ void ForNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
         generator.emitJump(topOfLoop.get());
 
     generator.emitLabel(scope->breakTarget());
         generator.emitJump(topOfLoop.get());
 
     generator.emitLabel(scope->breakTarget());

+    generator.emitProfileControlFlow(m_statement->endOffset() + (m_statement->isBlock() ? 1 : 0));

 }
 
 // ------------------------------ ForInNode ------------------------------------
 
 }
 
 // ------------------------------ ForInNode ------------------------------------
 

-void ForInNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
+RegisterID* ForInNode::tryGetBoundLocal(BytecodeGenerator& generator)

 {
 {

-    LabelScopePtr scope = generator.newLabelScope(LabelScope::Loop);
-
-    if (!m_lexpr->isAssignmentLocation()) {
-        emitThrowReferenceError(generator, "Left side of for-in statement is not a reference.");
-        return;
+    if (m_lexpr->isResolveNode()) {
+        const Identifier& ident = static_cast<ResolveNode*>(m_lexpr)->identifier();
+        return generator.variable(ident).local();

     }
 
     }
 

-    generator.emitDebugHook(WillExecuteStatement, firstLine(), startOffset(), lineStartOffset());
+    if (m_lexpr->isDestructuringNode()) {
+        DestructuringAssignmentNode* assignNode = static_cast<DestructuringAssignmentNode*>(m_lexpr);
+        auto binding = assignNode->bindings();
+        if (!binding->isBindingNode())
+            return nullptr;

 
 

-    RefPtr<RegisterID> base = generator.newTemporary();
-    generator.emitNode(base.get(), m_expr);
-    RefPtr<RegisterID> i = generator.newTemporary();
-    RefPtr<RegisterID> size = generator.newTemporary();
-    RefPtr<RegisterID> expectedSubscript;
-    RefPtr<RegisterID> iter = generator.emitGetPropertyNames(generator.newTemporary(), base.get(), i.get(), size.get(), scope->breakTarget());
-    generator.emitJump(scope->continueTarget());
+        auto simpleBinding = static_cast<BindingNode*>(binding);
+        const Identifier& ident = simpleBinding->boundProperty();
+        Variable var = generator.variable(ident);
+        if (var.isSpecial())
+            return nullptr;
+        return var.local();
+    }

 
 

-    RefPtr<Label> loopStart = generator.newLabel();
-    generator.emitLabel(loopStart.get());
-    generator.emitLoopHint();
+    return nullptr;
+}

 
 

-    RegisterID* propertyName;
-    bool optimizedForinAccess = false;
+void ForInNode::emitLoopHeader(BytecodeGenerator& generator, RegisterID* propertyName)
+{

     if (m_lexpr->isResolveNode()) {
         const Identifier& ident = static_cast<ResolveNode*>(m_lexpr)->identifier();
     if (m_lexpr->isResolveNode()) {
         const Identifier& ident = static_cast<ResolveNode*>(m_lexpr)->identifier();

-        Local local = generator.local(ident);
-        if (!local.get()) {
-            propertyName = generator.newTemporary();
-            RefPtr<RegisterID> protect = propertyName;
+        Variable var = generator.variable(ident);
+        if (RegisterID* local = var.local())
+            generator.emitMove(local, propertyName);
+        else {

             if (generator.isStrictMode())
                 generator.emitExpressionInfo(divot(), divotStart(), divotEnd());
             if (generator.isStrictMode())
                 generator.emitExpressionInfo(divot(), divotStart(), divotEnd());

-            RegisterID* scope = generator.emitResolveScope(generator.newTemporary(), ident);
+            RegisterID* scope = generator.emitResolveScope(nullptr, var);

             generator.emitExpressionInfo(divot(), divotStart(), divotEnd());
             generator.emitExpressionInfo(divot(), divotStart(), divotEnd());

-            generator.emitPutToScope(scope, ident, propertyName, generator.isStrictMode() ? ThrowIfNotFound : DoNotThrowIfNotFound);
-        } else {
-            expectedSubscript = generator.newTemporary();
-            propertyName = expectedSubscript.get();
-            generator.emitMove(local.get(), propertyName);
-            generator.pushOptimisedForIn(expectedSubscript.get(), iter.get(), i.get(), local.get());
-            optimizedForinAccess = true;
+            generator.emitPutToScope(scope, var, propertyName, generator.isStrictMode() ? ThrowIfNotFound : DoNotThrowIfNotFound);
+            if (generator.vm()->typeProfiler())
+                generator.emitProfileType(propertyName, var.isResolved() ? ProfileTypeBytecodePutToLocalScope : ProfileTypeBytecodePutToScope, &ident);

         }
         }

-    } else if (m_lexpr->isDotAccessorNode()) {
+        if (generator.vm()->typeProfiler())
+            generator.emitTypeProfilerExpressionInfo(m_lexpr->position(), JSTextPosition(-1, m_lexpr->position().offset + ident.length(), -1));
+        return;
+    }
+    if (m_lexpr->isDotAccessorNode()) {

         DotAccessorNode* assignNode = static_cast<DotAccessorNode*>(m_lexpr);
         const Identifier& ident = assignNode->identifier();
         DotAccessorNode* assignNode = static_cast<DotAccessorNode*>(m_lexpr);
         const Identifier& ident = assignNode->identifier();

-        propertyName = generator.newTemporary();
-        RefPtr<RegisterID> protect = propertyName;

         RegisterID* base = generator.emitNode(assignNode->base());
         RegisterID* base = generator.emitNode(assignNode->base());

-

         generator.emitExpressionInfo(assignNode->divot(), assignNode->divotStart(), assignNode->divotEnd());
         generator.emitPutById(base, ident, propertyName);
         generator.emitExpressionInfo(assignNode->divot(), assignNode->divotStart(), assignNode->divotEnd());
         generator.emitPutById(base, ident, propertyName);

-    } else if (m_lexpr->isBracketAccessorNode()) {
+        if (generator.vm()->typeProfiler()) {
+            generator.emitProfileType(propertyName, ProfileTypeBytecodeDoesNotHaveGlobalID, nullptr);
+            generator.emitTypeProfilerExpressionInfo(assignNode->divotStart(), assignNode->divotEnd());
+        }
+        return;
+    }
+    if (m_lexpr->isBracketAccessorNode()) {

         BracketAccessorNode* assignNode = static_cast<BracketAccessorNode*>(m_lexpr);
         BracketAccessorNode* assignNode = static_cast<BracketAccessorNode*>(m_lexpr);

-        propertyName = generator.newTemporary();
-        RefPtr<RegisterID> protect = propertyName;

         RefPtr<RegisterID> base = generator.emitNode(assignNode->base());
         RegisterID* subscript = generator.emitNode(assignNode->subscript());
         RefPtr<RegisterID> base = generator.emitNode(assignNode->base());
         RegisterID* subscript = generator.emitNode(assignNode->subscript());

-        

         generator.emitExpressionInfo(assignNode->divot(), assignNode->divotStart(), assignNode->divotEnd());
         generator.emitPutByVal(base.get(), subscript, propertyName);
         generator.emitExpressionInfo(assignNode->divot(), assignNode->divotStart(), assignNode->divotEnd());
         generator.emitPutByVal(base.get(), subscript, propertyName);

-    } else {
-        ASSERT(m_lexpr->isDeconstructionNode());
-        DeconstructingAssignmentNode* assignNode = static_cast<DeconstructingAssignmentNode*>(m_lexpr);
+        if (generator.vm()->typeProfiler()) {
+            generator.emitProfileType(propertyName, ProfileTypeBytecodeDoesNotHaveGlobalID, nullptr);
+            generator.emitTypeProfilerExpressionInfo(assignNode->divotStart(), assignNode->divotEnd());
+        }
+        return;
+    }
+
+    if (m_lexpr->isDestructuringNode()) {
+        DestructuringAssignmentNode* assignNode = static_cast<DestructuringAssignmentNode*>(m_lexpr);

         auto binding = assignNode->bindings();
         auto binding = assignNode->bindings();

-        if (binding->isBindingNode()) {
-            auto simpleBinding = static_cast<BindingNode*>(binding);
-            Identifier ident = simpleBinding->boundProperty();
-            Local local = generator.local(ident);
-            propertyName = local.get();
-            if (!propertyName || local.isCaptured())
-                goto genericBinding;
-            expectedSubscript = generator.emitMove(generator.newTemporary(), propertyName);
-            generator.pushOptimisedForIn(expectedSubscript.get(), iter.get(), i.get(), propertyName);
-            optimizedForinAccess = true;
-            goto completedSimpleBinding;
-        } else {
-        genericBinding:
-            propertyName = generator.newTemporary();
-            RefPtr<RegisterID> protect(propertyName);
+        if (!binding->isBindingNode()) {

             assignNode->bindings()->bindValue(generator, propertyName);
             assignNode->bindings()->bindValue(generator, propertyName);

+            return;

         }
         }

-        completedSimpleBinding:
-        ;
+
+        auto simpleBinding = static_cast<BindingNode*>(binding);
+        const Identifier& ident = simpleBinding->boundProperty();
+        Variable var = generator.variable(ident);
+        if (!var.local() || var.isSpecial()) {
+            assignNode->bindings()->bindValue(generator, propertyName);
+            return;
+        }
+        generator.emitMove(var.local(), propertyName);
+        if (generator.vm()->typeProfiler())
+            generator.emitTypeProfilerExpressionInfo(simpleBinding->divotStart(), simpleBinding->divotEnd());
+        return;

     }
 
     }
 

-    generator.emitNode(dst, m_statement);
+    RELEASE_ASSERT_NOT_REACHED();
+}
+
+void ForInNode::emitMultiLoopBytecode(BytecodeGenerator& generator, RegisterID* dst)
+{
+    if (!m_lexpr->isAssignmentLocation()) {
+        emitThrowReferenceError(generator, ASCIILiteral("Left side of for-in statement is not a reference."));
+        return;
+    }

 
 

-    if (optimizedForinAccess)
-        generator.popOptimisedForIn();
+    RefPtr<Label> end = generator.newLabel();

 
 

-    generator.emitLabel(scope->continueTarget());
-    generator.emitNextPropertyName(propertyName, base.get(), i.get(), size.get(), iter.get(), loopStart.get());

     generator.emitDebugHook(WillExecuteStatement, firstLine(), startOffset(), lineStartOffset());
     generator.emitDebugHook(WillExecuteStatement, firstLine(), startOffset(), lineStartOffset());

-    generator.emitLabel(scope->breakTarget());
+
+    RefPtr<RegisterID> base = generator.newTemporary();
+    RefPtr<RegisterID> length;
+    RefPtr<RegisterID> enumerator;
+    generator.emitNode(base.get(), m_expr);
+    RefPtr<RegisterID> local = this->tryGetBoundLocal(generator);
+    RefPtr<RegisterID> enumeratorIndex;
+
+    int profilerStartOffset = m_statement->startOffset();
+    int profilerEndOffset = m_statement->endOffset() + (m_statement->isBlock() ? 1 : 0);
+
+    enumerator = generator.emitGetPropertyEnumerator(generator.newTemporary(), base.get());
+
+    // Indexed property loop.
+    {
+        LabelScopePtr scope = generator.newLabelScope(LabelScope::Loop);
+        RefPtr<Label> loopStart = generator.newLabel();
+        RefPtr<Label> loopEnd = generator.newLabel();
+
+        length = generator.emitGetEnumerableLength(generator.newTemporary(), enumerator.get());
+        RefPtr<RegisterID> i = generator.emitLoad(generator.newTemporary(), jsNumber(0));
+        RefPtr<RegisterID> propertyName = generator.newTemporary();
+
+        generator.emitLabel(loopStart.get());
+        generator.emitLoopHint();
+
+        RefPtr<RegisterID> result = generator.emitEqualityOp(op_less, generator.newTemporary(), i.get(), length.get());
+        generator.emitJumpIfFalse(result.get(), loopEnd.get());
+        generator.emitHasIndexedProperty(result.get(), base.get(), i.get());
+        generator.emitJumpIfFalse(result.get(), scope->continueTarget());
+
+        generator.emitToIndexString(propertyName.get(), i.get());
+        this->emitLoopHeader(generator, propertyName.get());
+
+        generator.emitProfileControlFlow(profilerStartOffset);
+
+        generator.pushIndexedForInScope(local.get(), i.get());
+        generator.emitNode(dst, m_statement);
+        generator.popIndexedForInScope(local.get());
+
+        generator.emitProfileControlFlow(profilerEndOffset);
+
+        generator.emitLabel(scope->continueTarget());
+        generator.emitInc(i.get());
+        generator.emitJump(loopStart.get());
+
+        generator.emitLabel(scope->breakTarget());
+        generator.emitJump(end.get());
+        generator.emitLabel(loopEnd.get());
+    }
+
+    // Structure property loop.
+    {
+        LabelScopePtr scope = generator.newLabelScope(LabelScope::Loop);
+        RefPtr<Label> loopStart = generator.newLabel();
+        RefPtr<Label> loopEnd = generator.newLabel();
+
+        enumeratorIndex = generator.emitLoad(generator.newTemporary(), jsNumber(0));
+        RefPtr<RegisterID> propertyName = generator.newTemporary();
+        generator.emitEnumeratorStructurePropertyName(propertyName.get(), enumerator.get(), enumeratorIndex.get());
+
+        generator.emitLabel(loopStart.get());
+        generator.emitLoopHint();
+
+        RefPtr<RegisterID> result = generator.emitUnaryOp(op_eq_null, generator.newTemporary(), propertyName.get());
+        generator.emitJumpIfTrue(result.get(), loopEnd.get());
+        generator.emitHasStructureProperty(result.get(), base.get(), propertyName.get(), enumerator.get());
+        generator.emitJumpIfFalse(result.get(), scope->continueTarget());
+
+        this->emitLoopHeader(generator, propertyName.get());
+
+        generator.emitProfileControlFlow(profilerStartOffset);
+
+        generator.pushStructureForInScope(local.get(), enumeratorIndex.get(), propertyName.get(), enumerator.get());
+        generator.emitNode(dst, m_statement);
+        generator.popStructureForInScope(local.get());
+
+        generator.emitProfileControlFlow(profilerEndOffset);
+
+        generator.emitLabel(scope->continueTarget());
+        generator.emitInc(enumeratorIndex.get());
+        generator.emitEnumeratorStructurePropertyName(propertyName.get(), enumerator.get(), enumeratorIndex.get());
+        generator.emitJump(loopStart.get());
+        
+        generator.emitLabel(scope->breakTarget());
+        generator.emitJump(end.get());
+        generator.emitLabel(loopEnd.get());
+    }
+
+    // Generic property loop.
+    {
+        LabelScopePtr scope = generator.newLabelScope(LabelScope::Loop);
+        RefPtr<Label> loopStart = generator.newLabel();
+        RefPtr<Label> loopEnd = generator.newLabel();
+
+        RefPtr<RegisterID> propertyName = generator.newTemporary();
+
+        generator.emitEnumeratorGenericPropertyName(propertyName.get(), enumerator.get(), enumeratorIndex.get());
+
+        generator.emitLabel(loopStart.get());
+        generator.emitLoopHint();
+
+        RefPtr<RegisterID> result = generator.emitUnaryOp(op_eq_null, generator.newTemporary(), propertyName.get());
+        generator.emitJumpIfTrue(result.get(), loopEnd.get());
+
+        generator.emitHasGenericProperty(result.get(), base.get(), propertyName.get());
+        generator.emitJumpIfFalse(result.get(), scope->continueTarget());
+
+        this->emitLoopHeader(generator, propertyName.get());
+
+        generator.emitProfileControlFlow(profilerStartOffset);
+
+        generator.emitNode(dst, m_statement);
+
+        generator.emitLabel(scope->continueTarget());
+        generator.emitInc(enumeratorIndex.get());
+        generator.emitEnumeratorGenericPropertyName(propertyName.get(), enumerator.get(), enumeratorIndex.get());
+        generator.emitJump(loopStart.get());
+
+        generator.emitLabel(scope->breakTarget());
+        generator.emitJump(end.get());
+        generator.emitLabel(loopEnd.get());
+    }
+
+    generator.emitDebugHook(WillExecuteStatement, firstLine(), startOffset(), lineStartOffset());
+    generator.emitLabel(end.get());
+    generator.emitProfileControlFlow(profilerEndOffset);
+}
+
+void ForInNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
+{
+    this->emitMultiLoopBytecode(generator, dst);

 }
 
 // ------------------------------ ForOfNode ------------------------------------
 void ForOfNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
 {
     if (!m_lexpr->isAssignmentLocation()) {
 }
 
 // ------------------------------ ForOfNode ------------------------------------
 void ForOfNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
 {
     if (!m_lexpr->isAssignmentLocation()) {

-        emitThrowReferenceError(generator, "Left side of for-of statement is not a reference.");
+        emitThrowReferenceError(generator, ASCIILiteral("Left side of for-of statement is not a reference."));

         return;
     }
         return;
     }

-    
-    LabelScopePtr scope = generator.newLabelScope(LabelScope::Loop);
-    
+

     generator.emitDebugHook(WillExecuteStatement, firstLine(), startOffset(), lineStartOffset());
     auto extractor = [this, dst](BytecodeGenerator& generator, RegisterID* value)
     {
         if (m_lexpr->isResolveNode()) {
             const Identifier& ident = static_cast<ResolveNode*>(m_lexpr)->identifier();
     generator.emitDebugHook(WillExecuteStatement, firstLine(), startOffset(), lineStartOffset());
     auto extractor = [this, dst](BytecodeGenerator& generator, RegisterID* value)
     {
         if (m_lexpr->isResolveNode()) {
             const Identifier& ident = static_cast<ResolveNode*>(m_lexpr)->identifier();

-            if (Local local = generator.local(ident))
-                generator.emitMove(local.get(), value);
+            Variable var = generator.variable(ident);
+            if (RegisterID* local = var.local())
+                generator.emitMove(local, value);

             else {
                 if (generator.isStrictMode())
                     generator.emitExpressionInfo(divot(), divotStart(), divotEnd());
             else {
                 if (generator.isStrictMode())
                     generator.emitExpressionInfo(divot(), divotStart(), divotEnd());

-                RegisterID* scope = generator.emitResolveScope(generator.newTemporary(), ident);
+                RegisterID* scope = generator.emitResolveScope(nullptr, var);

                 generator.emitExpressionInfo(divot(), divotStart(), divotEnd());
                 generator.emitExpressionInfo(divot(), divotStart(), divotEnd());

-                generator.emitPutToScope(scope, ident, value, generator.isStrictMode() ? ThrowIfNotFound : DoNotThrowIfNotFound);
+                generator.emitPutToScope(scope, var, value, generator.isStrictMode() ? ThrowIfNotFound : DoNotThrowIfNotFound);
+                if (generator.vm()->typeProfiler())
+                    generator.emitProfileType(value, var.isResolved() ? ProfileTypeBytecodePutToLocalScope : ProfileTypeBytecodePutToScope, &ident);

             }
             }

+            if (generator.vm()->typeProfiler())
+                generator.emitTypeProfilerExpressionInfo(m_lexpr->position(), JSTextPosition(-1, m_lexpr->position().offset + ident.length(), -1));

         } else if (m_lexpr->isDotAccessorNode()) {
             DotAccessorNode* assignNode = static_cast<DotAccessorNode*>(m_lexpr);
             const Identifier& ident = assignNode->identifier();
         } else if (m_lexpr->isDotAccessorNode()) {
             DotAccessorNode* assignNode = static_cast<DotAccessorNode*>(m_lexpr);
             const Identifier& ident = assignNode->identifier();


@@ -1929,6 +2520,10 @@ void ForOfNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
             
             generator.emitExpressionInfo(assignNode->divot(), assignNode->divotStart(), assignNode->divotEnd());
             generator.emitPutById(base.get(), ident, value);
             
             generator.emitExpressionInfo(assignNode->divot(), assignNode->divotStart(), assignNode->divotEnd());
             generator.emitPutById(base.get(), ident, value);

+            if (generator.vm()->typeProfiler()) {
+                generator.emitProfileType(value, ProfileTypeBytecodeDoesNotHaveGlobalID, nullptr);
+                generator.emitTypeProfilerExpressionInfo(assignNode->divotStart(), assignNode->divotEnd());
+            }

         } else if (m_lexpr->isBracketAccessorNode()) {
             BracketAccessorNode* assignNode = static_cast<BracketAccessorNode*>(m_lexpr);
             RefPtr<RegisterID> base = generator.emitNode(assignNode->base());
         } else if (m_lexpr->isBracketAccessorNode()) {
             BracketAccessorNode* assignNode = static_cast<BracketAccessorNode*>(m_lexpr);
             RefPtr<RegisterID> base = generator.emitNode(assignNode->base());


@@ -1936,14 +2531,20 @@ void ForOfNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
             
             generator.emitExpressionInfo(assignNode->divot(), assignNode->divotStart(), assignNode->divotEnd());
             generator.emitPutByVal(base.get(), subscript, value);
             
             generator.emitExpressionInfo(assignNode->divot(), assignNode->divotStart(), assignNode->divotEnd());
             generator.emitPutByVal(base.get(), subscript, value);

+            if (generator.vm()->typeProfiler()) {
+                generator.emitProfileType(value, ProfileTypeBytecodeDoesNotHaveGlobalID, nullptr);
+                generator.emitTypeProfilerExpressionInfo(assignNode->divotStart(), assignNode->divotEnd());
+            }

         } else {
         } else {

-            ASSERT(m_lexpr->isDeconstructionNode());
-            DeconstructingAssignmentNode* assignNode = static_cast<DeconstructingAssignmentNode*>(m_lexpr);
+            ASSERT(m_lexpr->isDestructuringNode());
+            DestructuringAssignmentNode* assignNode = static_cast<DestructuringAssignmentNode*>(m_lexpr);

             assignNode->bindings()->bindValue(generator, value);
         }
             assignNode->bindings()->bindValue(generator, value);
         }

+        generator.emitProfileControlFlow(m_statement->startOffset());

         generator.emitNode(dst, m_statement);
     };
     generator.emitEnumeration(this, m_expr, extractor);
         generator.emitNode(dst, m_statement);
     };
     generator.emitEnumeration(this, m_expr, extractor);

+    generator.emitProfileControlFlow(m_statement->endOffset() + (m_statement->isBlock() ? 1 : 0));

 }
 
 // ------------------------------ ContinueNode ---------------------------------
 }
 
 // ------------------------------ ContinueNode ---------------------------------


@@ -1969,8 +2570,10 @@ void ContinueNode::emitBytecode(BytecodeGenerator& generator, RegisterID*)
     LabelScopePtr scope = generator.continueTarget(m_ident);
     ASSERT(scope);
 
     LabelScopePtr scope = generator.continueTarget(m_ident);
     ASSERT(scope);
 

-    generator.emitPopScopes(scope->scopeDepth());
+    generator.emitPopScopes(generator.scopeRegister(), scope->scopeDepth());

     generator.emitJump(scope->continueTarget());
     generator.emitJump(scope->continueTarget());

+
+    generator.emitProfileControlFlow(endOffset());

 }
 
 // ------------------------------ BreakNode ------------------------------------
 }
 
 // ------------------------------ BreakNode ------------------------------------


@@ -1996,8 +2599,10 @@ void BreakNode::emitBytecode(BytecodeGenerator& generator, RegisterID*)
     LabelScopePtr scope = generator.breakTarget(m_ident);
     ASSERT(scope);
 
     LabelScopePtr scope = generator.breakTarget(m_ident);
     ASSERT(scope);
 

-    generator.emitPopScopes(scope->scopeDepth());
+    generator.emitPopScopes(generator.scopeRegister(), scope->scopeDepth());

     generator.emitJump(scope->breakTarget());
     generator.emitJump(scope->breakTarget());

+
+    generator.emitProfileControlFlow(endOffset());

 }
 
 // ------------------------------ ReturnNode -----------------------------------
 }
 
 // ------------------------------ ReturnNode -----------------------------------


@@ -2011,13 +2616,22 @@ void ReturnNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
         dst = 0;
 
     RefPtr<RegisterID> returnRegister = m_value ? generator.emitNode(dst, m_value) : generator.emitLoad(dst, jsUndefined());
         dst = 0;
 
     RefPtr<RegisterID> returnRegister = m_value ? generator.emitNode(dst, m_value) : generator.emitLoad(dst, jsUndefined());

+    if (generator.vm()->typeProfiler()) {
+        generator.emitProfileType(returnRegister.get(), ProfileTypeBytecodeFunctionReturnStatement, nullptr);
+        generator.emitTypeProfilerExpressionInfo(divotStart(), divotEnd());
+    }

     if (generator.scopeDepth()) {
         returnRegister = generator.emitMove(generator.newTemporary(), returnRegister.get());
     if (generator.scopeDepth()) {
         returnRegister = generator.emitMove(generator.newTemporary(), returnRegister.get());

-        generator.emitPopScopes(0);
+        generator.emitPopScopes(generator.scopeRegister(), 0);

     }
 
     generator.emitDebugHook(WillLeaveCallFrame, lastLine(), startOffset(), lineStartOffset());
     generator.emitReturn(returnRegister.get());
     }
 
     generator.emitDebugHook(WillLeaveCallFrame, lastLine(), startOffset(), lineStartOffset());
     generator.emitReturn(returnRegister.get());

+    generator.emitProfileControlFlow(endOffset()); 
+    // Emitting an unreachable return here is needed in case this op_profile_control_flow is the 
+    // last opcode in a CodeBlock because a CodeBlock's instructions must end with a terminal opcode.
+    if (generator.vm()->controlFlowProfiler())
+        generator.emitReturn(generator.emitLoad(nullptr, jsUndefined()));

 }
 
 // ------------------------------ WithNode -------------------------------------
 }
 
 // ------------------------------ WithNode -------------------------------------


@@ -2028,15 +2642,16 @@ void WithNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
 
     RefPtr<RegisterID> scope = generator.emitNode(m_expr);
     generator.emitExpressionInfo(m_divot, m_divot - m_expressionLength, m_divot);
 
     RefPtr<RegisterID> scope = generator.emitNode(m_expr);
     generator.emitExpressionInfo(m_divot, m_divot - m_expressionLength, m_divot);

-    generator.emitPushWithScope(scope.get());
+    generator.emitPushWithScope(generator.scopeRegister(), scope.get());

     generator.emitNode(dst, m_statement);
     generator.emitNode(dst, m_statement);

-    generator.emitPopScope();
+    generator.emitPopScope(generator.scopeRegister());

 }
 
 // ------------------------------ CaseClauseNode --------------------------------
 
 inline void CaseClauseNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
 {
 }
 
 // ------------------------------ CaseClauseNode --------------------------------
 
 inline void CaseClauseNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
 {

+    generator.emitProfileControlFlow(m_startOffset);

     if (!m_statements)
         return;
     m_statements->emitBytecode(generator, dst);
     if (!m_statements)
         return;
     m_statements->emitBytecode(generator, dst);


@@ -2206,6 +2821,7 @@ void SwitchNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
     m_block->emitBytecodeForBlock(generator, r0.get(), dst);
 
     generator.emitLabel(scope->breakTarget());
     m_block->emitBytecodeForBlock(generator, r0.get(), dst);
 
     generator.emitLabel(scope->breakTarget());

+    generator.emitProfileControlFlow(endOffset());

 }
 
 // ------------------------------ LabelNode ------------------------------------
 }
 
 // ------------------------------ LabelNode ------------------------------------


@@ -2233,6 +2849,8 @@ void ThrowNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
     RefPtr<RegisterID> expr = generator.emitNode(m_expr);
     generator.emitExpressionInfo(divot(), divotStart(), divotEnd());
     generator.emitThrow(expr.get());
     RefPtr<RegisterID> expr = generator.emitNode(m_expr);
     generator.emitExpressionInfo(divot(), divotStart(), divotEnd());
     generator.emitThrow(expr.get());

+
+    generator.emitProfileControlFlow(endOffset()); 

 }
 
 // ------------------------------ TryNode --------------------------------------
 }
 
 // ------------------------------ TryNode --------------------------------------


@@ -2263,17 +2881,20 @@ void TryNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
 
         // Uncaught exception path: the catch block.
         RefPtr<Label> here = generator.emitLabel(generator.newLabel().get());
 
         // Uncaught exception path: the catch block.
         RefPtr<Label> here = generator.emitLabel(generator.newLabel().get());

-        RefPtr<RegisterID> exceptionRegister = generator.popTryAndEmitCatch(tryData, generator.newTemporary(), here.get());
+        RefPtr<RegisterID> exceptionRegister = generator.newTemporary();
+        RefPtr<RegisterID> thrownValueRegister = generator.newTemporary();
+        generator.popTryAndEmitCatch(tryData, exceptionRegister.get(), thrownValueRegister.get(), here.get(), HandlerType::Catch);

         
         if (m_finallyBlock) {
             // If the catch block throws an exception and we have a finally block, then the finally
             // block should "catch" that exception.
             tryData = generator.pushTry(here.get());
         }
         
         if (m_finallyBlock) {
             // If the catch block throws an exception and we have a finally block, then the finally
             // block should "catch" that exception.
             tryData = generator.pushTry(here.get());
         }

-        
-        generator.emitPushCatchScope(m_exceptionIdent, exceptionRegister.get(), DontDelete);
+
+        generator.emitPushCatchScope(generator.scopeRegister(), m_thrownValueIdent, thrownValueRegister.get(), DontDelete);
+        generator.emitProfileControlFlow(m_tryBlock->endOffset() + 1);

         generator.emitNode(dst, m_catchBlock);
         generator.emitNode(dst, m_catchBlock);

-        generator.emitPopScope();
+        generator.emitPopScope(generator.scopeRegister());

         generator.emitLabel(catchEndLabel.get());
     }
 
         generator.emitLabel(catchEndLabel.get());
     }
 


@@ -2284,17 +2905,27 @@ void TryNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
 
         RefPtr<Label> finallyEndLabel = generator.newLabel();
 
 
         RefPtr<Label> finallyEndLabel = generator.newLabel();
 

+        int finallyStartOffset = m_catchBlock ? m_catchBlock->endOffset() + 1 : m_tryBlock->endOffset() + 1;
+

         // Normal path: run the finally code, and jump to the end.
         // Normal path: run the finally code, and jump to the end.

+        generator.emitProfileControlFlow(finallyStartOffset);

         generator.emitNode(dst, m_finallyBlock);
         generator.emitNode(dst, m_finallyBlock);

+        generator.emitProfileControlFlow(m_finallyBlock->endOffset() + 1);

         generator.emitJump(finallyEndLabel.get());
 
         // Uncaught exception path: invoke the finally block, then re-throw the exception.
         generator.emitJump(finallyEndLabel.get());
 
         // Uncaught exception path: invoke the finally block, then re-throw the exception.

-        RefPtr<RegisterID> tempExceptionRegister = generator.popTryAndEmitCatch(tryData, generator.newTemporary(), preFinallyLabel.get());
+        RefPtr<RegisterID> exceptionRegister = generator.newTemporary();
+        RefPtr<RegisterID> thrownValueRegister = generator.newTemporary();
+        generator.popTryAndEmitCatch(tryData, exceptionRegister.get(), thrownValueRegister.get(), preFinallyLabel.get(), HandlerType::Finally);
+        generator.emitProfileControlFlow(finallyStartOffset);

         generator.emitNode(dst, m_finallyBlock);
         generator.emitNode(dst, m_finallyBlock);

-        generator.emitThrow(tempExceptionRegister.get());
+        generator.emitThrow(exceptionRegister.get());

 
         generator.emitLabel(finallyEndLabel.get());
 
         generator.emitLabel(finallyEndLabel.get());

-    }
+        generator.emitProfileControlFlow(m_finallyBlock->endOffset() + 1);
+    } else
+        generator.emitProfileControlFlow(m_catchBlock->endOffset() + 1);
+

 }
 
 // ------------------------------ ScopeNode -----------------------------
 }
 
 // ------------------------------ ScopeNode -----------------------------


@@ -2314,6 +2945,7 @@ void ProgramNode::emitBytecode(BytecodeGenerator& generator, RegisterID*)
 
     RefPtr<RegisterID> dstRegister = generator.newTemporary();
     generator.emitLoad(dstRegister.get(), jsUndefined());
 
     RefPtr<RegisterID> dstRegister = generator.newTemporary();
     generator.emitLoad(dstRegister.get(), jsUndefined());

+    generator.emitProfileControlFlow(startStartOffset());

     emitStatementsBytecode(generator, dstRegister.get());
 
     generator.emitDebugHook(DidExecuteProgram, lastLine(), startOffset(), lineStartOffset());
     emitStatementsBytecode(generator, dstRegister.get());
 
     generator.emitDebugHook(DidExecuteProgram, lastLine(), startOffset(), lineStartOffset());


@@ -2336,8 +2968,25 @@ void EvalNode::emitBytecode(BytecodeGenerator& generator, RegisterID*)
 
 // ------------------------------ FunctionBodyNode -----------------------------
 
 
 // ------------------------------ FunctionBodyNode -----------------------------
 

-void FunctionBodyNode::emitBytecode(BytecodeGenerator& generator, RegisterID*)
+void FunctionBodyNode::emitBytecode(BytecodeGenerator&, RegisterID*)

 {
 {

+}
+
+void FunctionNode::emitBytecode(BytecodeGenerator& generator, RegisterID*)
+{
+    if (generator.vm()->typeProfiler()) {
+        for (size_t i = 0; i < m_parameters->size(); i++) {
+            // FIXME: Handle Destructuring assignments into arguments.
+            if (!m_parameters->at(i)->isBindingNode())
+                continue;
+            BindingNode* parameter = static_cast<BindingNode*>(m_parameters->at(i));
+            RegisterID reg(CallFrame::argumentOffset(i));
+            generator.emitProfileType(&reg, ProfileTypeBytecodeFunctionArgument, nullptr);
+            generator.emitTypeProfilerExpressionInfo(parameter->divotStart(), parameter->divotEnd());
+        }
+    }
+
+    generator.emitProfileControlFlow(startStartOffset());

     generator.emitDebugHook(DidEnterCallFrame, startLine(), startStartOffset(), startLineStartOffset());
     emitStatementsBytecode(generator, generator.ignoredResult());
 
     generator.emitDebugHook(DidEnterCallFrame, startLine(), startStartOffset(), startLineStartOffset());
     emitStatementsBytecode(generator, generator.ignoredResult());
 


@@ -2354,27 +3003,13 @@ void FunctionBodyNode::emitBytecode(BytecodeGenerator& generator, RegisterID*)
     // If there is no return we must automatically insert one.
     if (!returnNode) {
         RegisterID* r0 = generator.isConstructor() ? generator.thisRegister() : generator.emitLoad(0, jsUndefined());
     // If there is no return we must automatically insert one.
     if (!returnNode) {
         RegisterID* r0 = generator.isConstructor() ? generator.thisRegister() : generator.emitLoad(0, jsUndefined());

+        if (generator.vm()->typeProfiler())
+            generator.emitProfileType(r0, ProfileTypeBytecodeFunctionReturnStatement, nullptr); // Do not emit expression info for this profile because it's not in the user's source code.

         ASSERT(startOffset() >= lineStartOffset());
         generator.emitDebugHook(WillLeaveCallFrame, lastLine(), startOffset(), lineStartOffset());
         generator.emitReturn(r0);
         return;
     }
         ASSERT(startOffset() >= lineStartOffset());
         generator.emitDebugHook(WillLeaveCallFrame, lastLine(), startOffset(), lineStartOffset());
         generator.emitReturn(r0);
         return;
     }

-
-    // If there is a return statment, and it is the only statement in the function, check if this is a numeric compare.
-    if (static_cast<BlockNode*>(singleStatement)->singleStatement()) {
-        ExpressionNode* returnValueExpression = returnNode->value();
-        if (returnValueExpression && returnValueExpression->isSubtract()) {
-            ExpressionNode* lhsExpression = static_cast<SubNode*>(returnValueExpression)->lhs();
-            ExpressionNode* rhsExpression = static_cast<SubNode*>(returnValueExpression)->rhs();
-            if (lhsExpression->isResolveNode()
-                && rhsExpression->isResolveNode()
-                && generator.isArgumentNumber(static_cast<ResolveNode*>(lhsExpression)->identifier(), 0)
-                && generator.isArgumentNumber(static_cast<ResolveNode*>(rhsExpression)->identifier(), 1)) {
-                
-                generator.setIsNumericCompareFunction(true);
-            }
-        }
-    }

 }
 
 // ------------------------------ FuncDeclNode ---------------------------------
 }
 
 // ------------------------------ FuncDeclNode ---------------------------------


@@ -2389,9 +3024,89 @@ RegisterID* FuncExprNode::emitBytecode(BytecodeGenerator& generator, RegisterID*
 {
     return generator.emitNewFunctionExpression(generator.finalDestination(dst), this);
 }
 {
     return generator.emitNewFunctionExpression(generator.finalDestination(dst), this);
 }

+
+#if ENABLE(ES6_CLASS_SYNTAX)
+// ------------------------------ ClassDeclNode ---------------------------------
+
+void ClassDeclNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
+{
+    generator.emitNode(dst, m_classDeclaration);
+}
+
+// ------------------------------ ClassExprNode ---------------------------------
+
+RegisterID* ClassExprNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
+{
+    RefPtr<RegisterID> superclass;
+    if (m_classHeritage) {
+        superclass = generator.newTemporary();
+        generator.emitNode(superclass.get(), m_classHeritage);
+    }
+
+    RefPtr<RegisterID> constructor;
+
+    // FIXME: Make the prototype non-configurable & non-writable.
+    if (m_constructorExpression)
+        constructor = generator.emitNode(dst, m_constructorExpression);
+    else {
+        constructor = generator.emitNewDefaultConstructor(generator.finalDestination(dst),
+            m_classHeritage ? ConstructorKind::Derived : ConstructorKind::Base, m_name);
+    }
+
+    const auto& propertyNames = generator.propertyNames();
+    RefPtr<RegisterID> prototype = generator.emitNewObject(generator.newTemporary());
+
+    if (superclass) {
+        RefPtr<RegisterID> protoParent = generator.newTemporary();
+        generator.emitLoad(protoParent.get(), jsNull());
+
+        RefPtr<RegisterID> tempRegister = generator.newTemporary();
+
+        // FIXME: Throw TypeError if it's a generator function.
+        RefPtr<Label> superclassIsUndefinedLabel = generator.newLabel();
+        generator.emitJumpIfTrue(generator.emitIsUndefined(tempRegister.get(), superclass.get()), superclassIsUndefinedLabel.get());
+
+        RefPtr<Label> superclassIsNullLabel = generator.newLabel();
+        generator.emitJumpIfTrue(generator.emitUnaryOp(op_eq_null, tempRegister.get(), superclass.get()), superclassIsNullLabel.get());
+
+        RefPtr<Label> superclassIsObjectLabel = generator.newLabel();
+        generator.emitJumpIfTrue(generator.emitIsObject(tempRegister.get(), superclass.get()), superclassIsObjectLabel.get());
+        generator.emitLabel(superclassIsUndefinedLabel.get());
+        generator.emitThrowTypeError(ASCIILiteral("The superclass is not an object."));
+        generator.emitLabel(superclassIsObjectLabel.get());
+        generator.emitGetById(protoParent.get(), superclass.get(), generator.propertyNames().prototype);
+
+        RefPtr<Label> protoParentIsObjectOrNullLabel = generator.newLabel();
+        generator.emitJumpIfTrue(generator.emitUnaryOp(op_is_object_or_null, tempRegister.get(), protoParent.get()), protoParentIsObjectOrNullLabel.get());
+        generator.emitThrowTypeError(ASCIILiteral("The superclass's prototype is not an object."));
+        generator.emitLabel(protoParentIsObjectOrNullLabel.get());
+
+        generator.emitDirectPutById(constructor.get(), generator.propertyNames().underscoreProto, superclass.get(), PropertyNode::Unknown);
+        generator.emitLabel(superclassIsNullLabel.get());
+        generator.emitDirectPutById(prototype.get(), generator.propertyNames().underscoreProto, protoParent.get(), PropertyNode::Unknown);
+
+        emitPutHomeObject(generator, constructor.get(), prototype.get());
+    }
+
+    RefPtr<RegisterID> constructorNameRegister = generator.emitLoad(generator.newTemporary(), propertyNames.constructor);
+    generator.emitCallDefineProperty(prototype.get(), constructorNameRegister.get(), constructor.get(), nullptr, nullptr,
+        BytecodeGenerator::PropertyConfigurable | BytecodeGenerator::PropertyWritable, m_position);
+
+    RefPtr<RegisterID> prototypeNameRegister = generator.emitLoad(generator.newTemporary(), propertyNames.prototype);
+    generator.emitCallDefineProperty(constructor.get(), prototypeNameRegister.get(), prototype.get(), nullptr, nullptr, 0, m_position);
+
+    if (m_staticMethods)
+        generator.emitNode(constructor.get(), m_staticMethods);
+
+    if (m_instanceMethods)
+        generator.emitNode(prototype.get(), m_instanceMethods);
+
+    return generator.moveToDestinationIfNeeded(dst, constructor.get());
+}
+#endif

     
     

-// ------------------------------ DeconstructingAssignmentNode -----------------
-RegisterID* DeconstructingAssignmentNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
+// ------------------------------ DestructuringAssignmentNode -----------------
+RegisterID* DestructuringAssignmentNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)

 {
     if (RegisterID* result = m_bindings->emitDirectBinding(generator, dst, m_initializer))
         return result;
 {
     if (RegisterID* result = m_bindings->emitDirectBinding(generator, dst, m_initializer))
         return result;


@@ -2401,43 +3116,106 @@ RegisterID* DeconstructingAssignmentNode::emitBytecode(BytecodeGenerator& genera
     return generator.moveToDestinationIfNeeded(dst, initializer.get());
 }
 
     return generator.moveToDestinationIfNeeded(dst, initializer.get());
 }
 

-DeconstructionPatternNode::~DeconstructionPatternNode()
+DestructuringPatternNode::~DestructuringPatternNode()

 {
 }
 {
 }

-    
+
+static void assignDefaultValueIfUndefined(BytecodeGenerator& generator, RegisterID* maybeUndefined, ExpressionNode* defaultValue)
+{
+    ASSERT(defaultValue);
+    RefPtr<Label> isNotUndefined = generator.newLabel();
+    generator.emitJumpIfFalse(generator.emitIsUndefined(generator.newTemporary(), maybeUndefined), isNotUndefined.get());
+    generator.emitNode(maybeUndefined, defaultValue);
+    generator.emitLabel(isNotUndefined.get());
+}
+

 void ArrayPatternNode::bindValue(BytecodeGenerator& generator, RegisterID* rhs) const
 {
 void ArrayPatternNode::bindValue(BytecodeGenerator& generator, RegisterID* rhs) const
 {

-    for (size_t i = 0; i < m_targetPatterns.size(); i++) {
-        auto target = m_targetPatterns[i];
-        if (!target)
-            continue;
-        RefPtr<RegisterID> temp = generator.newTemporary();
-        generator.emitLoad(temp.get(), jsNumber(i));
-        generator.emitGetByVal(temp.get(), rhs, temp.get());
-        target->bindValue(generator, temp.get());
+    RefPtr<RegisterID> iterator = generator.newTemporary();
+    {
+        generator.emitGetById(iterator.get(), rhs, generator.propertyNames().iteratorSymbol);
+        CallArguments args(generator, nullptr);
+        generator.emitMove(args.thisRegister(), rhs);
+        generator.emitCall(iterator.get(), iterator.get(), NoExpectedFunction, args, divot(), divotStart(), divotEnd());
+    }
+
+    if (m_targetPatterns.isEmpty()) {
+        generator.emitIteratorClose(iterator.get(), this);
+        return;
+    }
+
+    RefPtr<RegisterID> done;
+    for (auto& target : m_targetPatterns) {
+        switch (target.bindingType) {
+        case BindingType::Elision:
+        case BindingType::Element: {
+            RefPtr<Label> iterationSkipped = generator.newLabel();
+            if (!done)
+                done = generator.newTemporary();
+            else
+                generator.emitJumpIfTrue(done.get(), iterationSkipped.get());
+
+            RefPtr<RegisterID> value = generator.newTemporary();
+            generator.emitIteratorNext(value.get(), iterator.get(), this);
+            generator.emitGetById(done.get(), value.get(), generator.propertyNames().done);
+            generator.emitJumpIfTrue(done.get(), iterationSkipped.get());
+            generator.emitGetById(value.get(), value.get(), generator.propertyNames().value);
+
+            {
+                RefPtr<Label> valueIsSet = generator.newLabel();
+                generator.emitJump(valueIsSet.get());
+                generator.emitLabel(iterationSkipped.get());
+                generator.emitLoad(value.get(), jsUndefined());
+                generator.emitLabel(valueIsSet.get());
+            }
+
+            if (target.bindingType == BindingType::Element) {
+                if (target.defaultValue)
+                    assignDefaultValueIfUndefined(generator, value.get(), target.defaultValue);
+                target.pattern->bindValue(generator, value.get());
+            }
+            break;
+        }
+
+        case BindingType::RestElement: {
+            RefPtr<RegisterID> array = generator.emitNewArray(generator.newTemporary(), 0, 0);
+
+            RefPtr<Label> iterationDone = generator.newLabel();
+            if (!done)
+                done = generator.newTemporary();
+            else
+                generator.emitJumpIfTrue(done.get(), iterationDone.get());
+
+            RefPtr<RegisterID> index = generator.newTemporary();
+            generator.emitLoad(index.get(), jsNumber(0));
+            RefPtr<Label> loopStart = generator.newLabel();
+            generator.emitLabel(loopStart.get());
+
+            RefPtr<RegisterID> value = generator.newTemporary();
+            generator.emitIteratorNext(value.get(), iterator.get(), this);
+            generator.emitGetById(done.get(), value.get(), generator.propertyNames().done);
+            generator.emitJumpIfTrue(done.get(), iterationDone.get());
+            generator.emitGetById(value.get(), value.get(), generator.propertyNames().value);
+
+            generator.emitDirectPutByVal(array.get(), index.get(), value.get());
+            generator.emitInc(index.get());
+            generator.emitJump(loopStart.get());
+
+            generator.emitLabel(iterationDone.get());
+            target.pattern->bindValue(generator, array.get());
+            break;
+        }
+        }

     }
     }

+
+    RefPtr<Label> iteratorClosed = generator.newLabel();
+    generator.emitJumpIfTrue(done.get(), iteratorClosed.get());
+    generator.emitIteratorClose(iterator.get(), this);
+    generator.emitLabel(iteratorClosed.get());

 }
 
 RegisterID* ArrayPatternNode::emitDirectBinding(BytecodeGenerator& generator, RegisterID* dst, ExpressionNode* rhs)
 {
 }
 
 RegisterID* ArrayPatternNode::emitDirectBinding(BytecodeGenerator& generator, RegisterID* dst, ExpressionNode* rhs)
 {

-    if (rhs->isResolveNode()
-        && generator.willResolveToArguments(static_cast<ResolveNode*>(rhs)->identifier())
-        && !generator.symbolTable().slowArguments()) {
-        for (size_t i = 0; i < m_targetPatterns.size(); i++) {
-            auto target = m_targetPatterns[i];
-            if (!target)
-                continue;
-            
-            RefPtr<RegisterID> temp = generator.newTemporary();
-            generator.emitLoad(temp.get(), jsNumber(i));
-            generator.emitGetArgumentByVal(temp.get(), generator.uncheckedRegisterForArguments(), temp.get());
-            target->bindValue(generator, temp.get());
-        }
-        if (dst == generator.ignoredResult() || !dst)
-            return generator.emitLoad(generator.finalDestination(dst), jsUndefined());
-        Local local = generator.local(generator.vm()->propertyNames->arguments);
-        return generator.moveToDestinationIfNeeded(dst, local.get());
-    }

     if (!rhs->isSimpleArray())
         return 0;
 
     if (!rhs->isSimpleArray())
         return 0;
 


@@ -2455,13 +3233,15 @@ RegisterID* ArrayPatternNode::emitDirectBinding(BytecodeGenerator& generator, Re
     for (size_t i = 0; i < m_targetPatterns.size(); i++) {
         registers.uncheckedAppend(generator.newTemporary());
         generator.emitNode(registers.last().get(), elements[i]);
     for (size_t i = 0; i < m_targetPatterns.size(); i++) {
         registers.uncheckedAppend(generator.newTemporary());
         generator.emitNode(registers.last().get(), elements[i]);

+        if (m_targetPatterns[i].defaultValue)
+            assignDefaultValueIfUndefined(generator, registers.last().get(), m_targetPatterns[i].defaultValue);

         if (resultRegister)
             generator.emitPutByIndex(resultRegister.get(), i, registers.last().get());
     }
     
     for (size_t i = 0; i < m_targetPatterns.size(); i++) {
         if (resultRegister)
             generator.emitPutByIndex(resultRegister.get(), i, registers.last().get());
     }
     
     for (size_t i = 0; i < m_targetPatterns.size(); i++) {

-        if (m_targetPatterns[i])
-            m_targetPatterns[i]->bindValue(generator, registers[i].get());
+        if (m_targetPatterns[i].pattern)
+            m_targetPatterns[i].pattern->bindValue(generator, registers[i].get());

     }
     if (resultRegister)
         return generator.moveToDestinationIfNeeded(dst, resultRegister.get());
     }
     if (resultRegister)
         return generator.moveToDestinationIfNeeded(dst, resultRegister.get());


@@ -2472,13 +3252,24 @@ void ArrayPatternNode::toString(StringBuilder& builder) const
 {
     builder.append('[');
     for (size_t i = 0; i < m_targetPatterns.size(); i++) {
 {
     builder.append('[');
     for (size_t i = 0; i < m_targetPatterns.size(); i++) {

-        if (!m_targetPatterns[i]) {
+        const auto& target = m_targetPatterns[i];
+
+        switch (target.bindingType) {
+        case BindingType::Elision:

             builder.append(',');
             builder.append(',');

-            continue;
+            break;
+
+        case BindingType::Element:
+            target.pattern->toString(builder);
+            if (i < m_targetPatterns.size() - 1)
+                builder.append(',');
+            break;
+
+        case BindingType::RestElement:
+            builder.append("...");
+            target.pattern->toString(builder);
+            break;

         }
         }

-        m_targetPatterns[i]->toString(builder);
-        if (i < m_targetPatterns.size() - 1)
-            builder.append(',');

     }
     builder.append(']');
 }
     }
     builder.append(']');
 }


@@ -2486,7 +3277,7 @@ void ArrayPatternNode::toString(StringBuilder& builder) const
 void ArrayPatternNode::collectBoundIdentifiers(Vector<Identifier>& identifiers) const
 {
     for (size_t i = 0; i < m_targetPatterns.size(); i++) {
 void ArrayPatternNode::collectBoundIdentifiers(Vector<Identifier>& identifiers) const
 {
     for (size_t i = 0; i < m_targetPatterns.size(); i++) {

-        if (DeconstructionPatternNode* node = m_targetPatterns[i].get())
+        if (DestructuringPatternNode* node = m_targetPatterns[i].pattern.get())

             node->collectBoundIdentifiers(identifiers);
     }
 }
             node->collectBoundIdentifiers(identifiers);
     }
 }


@@ -2495,13 +3286,11 @@ void ObjectPatternNode::toString(StringBuilder& builder) const
 {
     builder.append('{');
     for (size_t i = 0; i < m_targetPatterns.size(); i++) {
 {
     builder.append('{');
     for (size_t i = 0; i < m_targetPatterns.size(); i++) {

-        if (m_targetPatterns[i].wasString) {
-            builder.append('"');
-            escapeStringToBuilder(builder, m_targetPatterns[i].propertyName.string());
-            builder.append('"');
-        } else
+        if (m_targetPatterns[i].wasString)
+            builder.appendQuotedJSONString(m_targetPatterns[i].propertyName.string());
+        else

             builder.append(m_targetPatterns[i].propertyName.string());
             builder.append(m_targetPatterns[i].propertyName.string());

-        builder.append(":");
+        builder.append(':');

         m_targetPatterns[i].pattern->toString(builder);
         if (i < m_targetPatterns.size() - 1)
             builder.append(',');
         m_targetPatterns[i].pattern->toString(builder);
         if (i < m_targetPatterns.size() - 1)
             builder.append(',');


@@ -2515,6 +3304,8 @@ void ObjectPatternNode::bindValue(BytecodeGenerator& generator, RegisterID* rhs)
         auto& target = m_targetPatterns[i];
         RefPtr<RegisterID> temp = generator.newTemporary();
         generator.emitGetById(temp.get(), rhs, target.propertyName);
         auto& target = m_targetPatterns[i];
         RefPtr<RegisterID> temp = generator.newTemporary();
         generator.emitGetById(temp.get(), rhs, target.propertyName);

+        if (target.defaultValue)
+            assignDefaultValueIfUndefined(generator, temp.get(), target.defaultValue);

         target.pattern->bindValue(generator, temp.get());
     }
 }
         target.pattern->bindValue(generator, temp.get());
     }
 }


@@ -2527,19 +3318,26 @@ void ObjectPatternNode::collectBoundIdentifiers(Vector<Identifier>& identifiers)
 
 void BindingNode::bindValue(BytecodeGenerator& generator, RegisterID* value) const
 {
 
 void BindingNode::bindValue(BytecodeGenerator& generator, RegisterID* value) const
 {

-    if (Local local = generator.local(m_boundProperty)) {
-        if (local.isReadOnly()) {
+    Variable var = generator.variable(m_boundProperty);
+    if (RegisterID* local = var.local()) {
+        if (var.isReadOnly()) {

             generator.emitReadOnlyExceptionIfNeeded();
             return;
         }
             generator.emitReadOnlyExceptionIfNeeded();
             return;
         }

-        generator.emitMove(local.get(), value);
+        generator.emitMove(local, value);
+        if (generator.vm()->typeProfiler())
+            generator.emitTypeProfilerExpressionInfo(divotStart(), divotEnd());

         return;
     }
     if (generator.isStrictMode())
         generator.emitExpressionInfo(divotEnd(), divotStart(), divotEnd());
         return;
     }
     if (generator.isStrictMode())
         generator.emitExpressionInfo(divotEnd(), divotStart(), divotEnd());

-    RegisterID* scope = generator.emitResolveScope(generator.newTemporary(), m_boundProperty);
+    RegisterID* scope = generator.emitResolveScope(nullptr, var);

     generator.emitExpressionInfo(divotEnd(), divotStart(), divotEnd());
     generator.emitExpressionInfo(divotEnd(), divotStart(), divotEnd());

-    generator.emitPutToScope(scope, m_boundProperty, value, generator.isStrictMode() ? ThrowIfNotFound : DoNotThrowIfNotFound);
+    generator.emitPutToScope(scope, var, value, generator.isStrictMode() ? ThrowIfNotFound : DoNotThrowIfNotFound);
+    if (generator.vm()->typeProfiler()) {
+        generator.emitProfileType(value, var.isResolved() ? ProfileTypeBytecodePutToLocalScope : ProfileTypeBytecodePutToScope, &m_boundProperty);
+        generator.emitTypeProfilerExpressionInfo(divotStart(), divotEnd());
+    }

     return;
 }
 
     return;
 }