A64: Synchronize with r16249.

src/hydrogen-instructions.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 79 matching lines @@
   V(Change)                                    \
   V(CheckFunction)                             \
   V(CheckHeapObject)                           \
   V(CheckInstanceType)                         \
   V(CheckMaps)                                 \
   V(CheckMapValue)                             \
   V(CheckSmi)                                  \
   V(ClampToUint8)                              \
   V(ClassOfTestAndBranch)                      \
   V(CompareNumericAndBranch)                   \
+  V(CompareHoleAndBranch)                      \
   V(CompareGeneric)                            \
   V(CompareObjectEqAndBranch)                  \
   V(CompareMap)                                \
   V(Constant)                                  \
   V(Context)                                   \
   V(DateField)                                 \
   V(DebugBreak)                                \
   V(DeclareGlobals)                            \
   V(Deoptimize)                                \
   V(Div)                                       \
@@ skipping 25 matching lines @@
   V(LeaveInlined)                              \
   V(LoadContextSlot)                           \
   V(LoadExternalArrayPointer)                  \
   V(LoadFieldByIndex)                          \
   V(LoadFunctionPrototype)                     \
   V(LoadGlobalCell)                            \
   V(LoadGlobalGeneric)                         \
   V(LoadKeyed)                                 \
   V(LoadKeyedGeneric)                          \
   V(LoadNamedField)                            \
-  V(LoadNamedFieldPolymorphic)                 \
   V(LoadNamedGeneric)                          \
   V(MapEnumLength)                             \
   V(MathFloorOfDiv)                            \
   V(MathMinMax)                                \
   V(Mod)                                       \
   V(Mul)                                       \
   V(OsrEntry)                                  \
   V(OuterContext)                              \
   V(Parameter)                                 \
   V(Power)                                     \
@@ skipping 47 matching lines @@
   V(DoubleArrayElements)                       \
   V(DoubleFields)                              \
   V(ElementsKind)                              \
   V(ElementsPointer)                           \
   V(GlobalVars)                                \
   V(InobjectFields)                            \
   V(OsrEntries)                                \
   V(ExternalMemory)
 
 
-#define DECLARE_ABSTRACT_INSTRUCTION(type)          \
-  virtual bool Is##type() const { return true; }    \
-  static H##type* cast(HValue* value) {             \
-    ASSERT(value->Is##type());                      \
-    return reinterpret_cast<H##type*>(value);       \
+#define DECLARE_ABSTRACT_INSTRUCTION(type)                              \
+  virtual bool Is##type() const V8_FINAL V8_OVERRIDE { return true; }   \
+  static H##type* cast(HValue* value) {                                 \
+    ASSERT(value->Is##type());                                          \
+    return reinterpret_cast<H##type*>(value);                           \
   }
 
 
-#define DECLARE_CONCRETE_INSTRUCTION(type)                        \
-  virtual LInstruction* CompileToLithium(LChunkBuilder* builder); \
-  static H##type* cast(HValue* value) {                           \
-    ASSERT(value->Is##type());                                    \
-    return reinterpret_cast<H##type*>(value);                     \
-  }                                                               \
-  virtual Opcode opcode() const { return HValue::k##type; }
+#define DECLARE_CONCRETE_INSTRUCTION(type)              \
+  virtual LInstruction* CompileToLithium(               \
+     LChunkBuilder* builder) V8_FINAL V8_OVERRIDE;      \
+  static H##type* cast(HValue* value) {                 \
+    ASSERT(value->Is##type());                          \
+    return reinterpret_cast<H##type*>(value);           \
+  }                                                     \
+  virtual Opcode opcode() const V8_FINAL V8_OVERRIDE {  \
+    return HValue::k##type;                             \
+  }
 
 
-class Range: public ZoneObject {
+class Range V8_FINAL : public ZoneObject {
  public:
   Range()
       : lower_(kMinInt),
         upper_(kMaxInt),
         next_(NULL),
         can_be_minus_zero_(false) { }
 
   Range(int32_t lower, int32_t upper)
       : lower_(lower),
         upper_(upper),
@@ skipping 54 matching lines @@
   bool MulAndCheckOverflow(const Representation& r, Range* other);
 
  private:
   int32_t lower_;
   int32_t upper_;
   Range* next_;
   bool can_be_minus_zero_;
 };
 
 
-class UniqueValueId {
+class UniqueValueId V8_FINAL {
  public:
   UniqueValueId() : raw_address_(NULL) { }
 
   explicit UniqueValueId(Object* object) {
     raw_address_ = reinterpret_cast<Address>(object);
     ASSERT(IsInitialized());
   }
 
   explicit UniqueValueId(Handle<Object> handle) {
     static const Address kEmptyHandleSentinel = reinterpret_cast<Address>(1);
@@ skipping 21 matching lines @@
   intptr_t Hashcode() const {
     ASSERT(IsInitialized());
     return reinterpret_cast<intptr_t>(raw_address_);
   }
 
  private:
   Address raw_address_;
 };
 
 
-class HType {
+class HType V8_FINAL {
  public:
   static HType None() { return HType(kNone); }
   static HType Tagged() { return HType(kTagged); }
   static HType TaggedPrimitive() { return HType(kTaggedPrimitive); }
   static HType TaggedNumber() { return HType(kTaggedNumber); }
   static HType Smi() { return HType(kSmi); }
   static HType HeapNumber() { return HType(kHeapNumber); }
   static HType String() { return HType(kString); }
   static HType Boolean() { return HType(kBoolean); }
   static HType NonPrimitive() { return HType(kNonPrimitive); }
@@ skipping 130 matching lines @@
 
  private:
   HUseListNode* tail_;
   HValue* value_;
   int index_;
 };
 
 
 // We reuse use list nodes behind the scenes as uses are added and deleted.
 // This class is the safe way to iterate uses while deleting them.
-class HUseIterator BASE_EMBEDDED {
+class HUseIterator V8_FINAL BASE_EMBEDDED {
  public:
   bool Done() { return current_ == NULL; }
   void Advance();
 
   HValue* value() {
     ASSERT(!Done());
     return value_;
   }
 
   int index() {
@@ skipping 23 matching lines @@
   GVN_UNTRACKED_FLAG_LIST(DECLARE_FLAG)
 #undef DECLARE_FLAG
   kAfterLastFlag,
   kLastFlag = kAfterLastFlag - 1,
 #define COUNT_FLAG(type) + 1
   kNumberOfTrackedSideEffects = 0 GVN_TRACKED_FLAG_LIST(COUNT_FLAG)
 #undef COUNT_FLAG
 };
 
 
-class DecompositionResult BASE_EMBEDDED {
+class DecompositionResult V8_FINAL BASE_EMBEDDED {
  public:
   DecompositionResult() : base_(NULL), offset_(0), scale_(0) {}
 
   HValue* base() { return base_; }
   int offset() { return offset_; }
   int scale() { return scale_; }
 
   bool Apply(HValue* other_base, int other_offset, int other_scale = 0) {
     if (base_ == NULL) {
       base_ = other_base;
@@ skipping 27 matching lines @@
 
   HValue* base_;
   int offset_;
   int scale_;
 };
 
 
 typedef EnumSet<GVNFlag> GVNFlagSet;
 
 
-class HValue: public ZoneObject {
+class HValue : public ZoneObject {
  public:
   static const int kNoNumber = -1;
 
   enum Flag {
     kFlexibleRepresentation,
     kCannotBeTagged,
     // Participate in Global Value Numbering, i.e. elimination of
     // unnecessary recomputations. If an instruction sets this flag, it must
     // implement DataEquals(), which will be used to determine if other
     // occurrences of the instruction are indeed the same.
@@ skipping 194 matching lines @@
 
   // Mark this HValue as dead and to be removed from other HValues' use lists.
   void Kill();
 
   int flags() const { return flags_; }
   void SetFlag(Flag f) { flags_ |= (1 << f); }
   void ClearFlag(Flag f) { flags_ &= ~(1 << f); }
   bool CheckFlag(Flag f) const { return (flags_ & (1 << f)) != 0; }
 
   // Returns true if the flag specified is set for all uses, false otherwise.
-  bool CheckUsesForFlag(Flag f);
+  bool CheckUsesForFlag(Flag f) const;
   // Returns true if the flag specified is set for all uses, and this set
   // of uses is non-empty.
-  bool HasAtLeastOneUseWithFlagAndNoneWithout(Flag f);
+  bool HasAtLeastOneUseWithFlagAndNoneWithout(Flag f) const;
 
   GVNFlagSet gvn_flags() const { return gvn_flags_; }
   void SetGVNFlag(GVNFlag f) { gvn_flags_.Add(f); }
   void ClearGVNFlag(GVNFlag f) { gvn_flags_.Remove(f); }
   bool CheckGVNFlag(GVNFlag f) const { return gvn_flags_.Contains(f); }
   void SetAllSideEffects() { gvn_flags_.Add(AllSideEffectsFlagSet()); }
   void ClearAllSideEffects() {
     gvn_flags_.Remove(AllSideEffectsFlagSet());
   }
   bool HasSideEffects() const {
@@ skipping 256 matching lines @@
                 HValue* context,                                               \
                 P1 p1,                                                         \
                 P2 p2,                                                         \
                 P3 p3,                                                         \
                 P4 p4,                                                         \
                 P5 p5) {                                                       \
     return new(zone) I(p1, p2, p3, p4, p5);                                    \
   }
 
 
-class HInstruction: public HValue {
+class HInstruction : public HValue {
  public:
   HInstruction* next() const { return next_; }
   HInstruction* previous() const { return previous_; }
 
-  virtual void PrintTo(StringStream* stream);
+  virtual void PrintTo(StringStream* stream) V8_OVERRIDE;
   virtual void PrintDataTo(StringStream* stream);
 
   bool IsLinked() const { return block() != NULL; }
   void Unlink();
   void InsertBefore(HInstruction* next);
   void InsertAfter(HInstruction* previous);
 
   // The position is a write-once variable.
   int position() const { return position_; }
   bool has_position() const { return position_ != RelocInfo::kNoPosition; }
   void set_position(int position) {
     ASSERT(!has_position());
     ASSERT(position != RelocInfo::kNoPosition);
     position_ = position;
   }
 
   bool CanTruncateToInt32() const { return CheckFlag(kTruncatingToInt32); }
 
   virtual LInstruction* CompileToLithium(LChunkBuilder* builder) = 0;
 
 #ifdef DEBUG
-  virtual void Verify();
+  virtual void Verify() V8_OVERRIDE;
 #endif
 
   virtual bool IsCall() { return false; }
 
   DECLARE_ABSTRACT_INSTRUCTION(Instruction)
 
  protected:
   HInstruction(HType type = HType::Tagged())
       : HValue(type),
         next_(NULL),
         previous_(NULL),
         position_(RelocInfo::kNoPosition) {
     SetGVNFlag(kDependsOnOsrEntries);
   }
 
-  virtual void DeleteFromGraph() { Unlink(); }
+  virtual void DeleteFromGraph() V8_OVERRIDE { Unlink(); }
 
  private:
   void InitializeAsFirst(HBasicBlock* block) {
     ASSERT(!IsLinked());
     SetBlock(block);
   }
 
   void PrintMnemonicTo(StringStream* stream);
 
   HInstruction* next_;
   HInstruction* previous_;
   int position_;
 
   friend class HBasicBlock;
 };
 
 
 template<int V>
 class HTemplateInstruction : public HInstruction {
  public:
-  int OperandCount() { return V; }
-  HValue* OperandAt(int i) const { return inputs_[i]; }
+  virtual int OperandCount() V8_FINAL V8_OVERRIDE { return V; }
+  virtual HValue* OperandAt(int i) const V8_FINAL V8_OVERRIDE {
+    return inputs_[i];
+  }
 
  protected:
   HTemplateInstruction(HType type = HType::Tagged()) : HInstruction(type) {}
 
-  void InternalSetOperandAt(int i, HValue* value) { inputs_[i] = value; }
+  virtual void InternalSetOperandAt(int i, HValue* value) V8_FINAL V8_OVERRIDE {
+    inputs_[i] = value;
+  }
 
  private:
   EmbeddedContainer<HValue*, V> inputs_;
 };
 
 
-class HControlInstruction: public HInstruction {
+class HControlInstruction : public HInstruction {
  public:
   virtual HBasicBlock* SuccessorAt(int i) = 0;
   virtual int SuccessorCount() = 0;
   virtual void SetSuccessorAt(int i, HBasicBlock* block) = 0;
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
   HBasicBlock* FirstSuccessor() {
     return SuccessorCount() > 0 ? SuccessorAt(0) : NULL;
   }
   HBasicBlock* SecondSuccessor() {
     return SuccessorCount() > 1 ? SuccessorAt(1) : NULL;
   }
 
   DECLARE_ABSTRACT_INSTRUCTION(ControlInstruction)
 };
 
 
-class HSuccessorIterator BASE_EMBEDDED {
+class HSuccessorIterator V8_FINAL BASE_EMBEDDED {
  public:
   explicit HSuccessorIterator(HControlInstruction* instr)
       : instr_(instr), current_(0) { }
 
   bool Done() { return current_ >= instr_->SuccessorCount(); }
   HBasicBlock* Current() { return instr_->SuccessorAt(current_); }
   void Advance() { current_++; }
 
  private:
   HControlInstruction* instr_;
   int current_;
 };
 
 
 template<int S, int V>
-class HTemplateControlInstruction: public HControlInstruction {
+class HTemplateControlInstruction : public HControlInstruction {
  public:
-  int SuccessorCount() { return S; }
-  HBasicBlock* SuccessorAt(int i) { return successors_[i]; }
-  void SetSuccessorAt(int i, HBasicBlock* block) { successors_[i] = block; }
+  int SuccessorCount() V8_OVERRIDE { return S; }
+  HBasicBlock* SuccessorAt(int i) V8_OVERRIDE { return successors_[i]; }
+  void SetSuccessorAt(int i, HBasicBlock* block) V8_OVERRIDE {
+    successors_[i] = block;
+  }
 
-  int OperandCount() { return V; }
-  HValue* OperandAt(int i) const { return inputs_[i]; }
+  int OperandCount() V8_OVERRIDE { return V; }
+  HValue* OperandAt(int i) const V8_OVERRIDE { return inputs_[i]; }
 
 
  protected:
-  void InternalSetOperandAt(int i, HValue* value) { inputs_[i] = value; }
+  void InternalSetOperandAt(int i, HValue* value) V8_OVERRIDE {
+    inputs_[i] = value;
+  }
 
  private:
   EmbeddedContainer<HBasicBlock*, S> successors_;
   EmbeddedContainer<HValue*, V> inputs_;
 };
 
 
-class HBlockEntry: public HTemplateInstruction<0> {
+class HBlockEntry V8_FINAL : public HTemplateInstruction<0> {
  public:
-  virtual Representation RequiredInputRepresentation(int index) {
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     return Representation::None();
   }
 
   DECLARE_CONCRETE_INSTRUCTION(BlockEntry)
 };
 
 
-class HDummyUse: public HTemplateInstruction<1> {
+class HDummyUse V8_FINAL : public HTemplateInstruction<1> {
  public:
   explicit HDummyUse(HValue* value)
       : HTemplateInstruction<1>(HType::Smi()) {
     SetOperandAt(0, value);
     // Pretend to be a Smi so that the HChange instructions inserted
     // before any use generate as little code as possible.
     set_representation(Representation::Tagged());
   }
 
   HValue* value() { return OperandAt(0); }
 
-  virtual bool HasEscapingOperandAt(int index) { return false; }
-  virtual Representation RequiredInputRepresentation(int index) {
+  virtual bool HasEscapingOperandAt(int index) V8_OVERRIDE { return false; }
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     return Representation::None();
   }
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
   DECLARE_CONCRETE_INSTRUCTION(DummyUse);
 };
 
 
-class HDeoptimize: public HTemplateInstruction<0> {
+class HDeoptimize V8_FINAL : public HTemplateInstruction<0> {
  public:
-  DECLARE_INSTRUCTION_FACTORY_P1(HDeoptimize, Deoptimizer::BailoutType);
+  DECLARE_INSTRUCTION_FACTORY_P2(HDeoptimize, const char*,
+                                 Deoptimizer::BailoutType);
 
-  virtual Representation RequiredInputRepresentation(int index) {
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     return Representation::None();
   }
 
+  const char* reason() const { return reason_; }
   Deoptimizer::BailoutType type() { return type_; }
 
   DECLARE_CONCRETE_INSTRUCTION(Deoptimize)
 
  private:
-  explicit HDeoptimize(Deoptimizer::BailoutType type) : type_(type) {}
+  explicit HDeoptimize(const char* reason, Deoptimizer::BailoutType type)
+      : reason_(reason), type_(type) {}
 
+  const char* reason_;
   Deoptimizer::BailoutType type_;
 };
 
 
 // Inserts an int3/stop break instruction for debugging purposes.
-class HDebugBreak: public HTemplateInstruction<0> {
+class HDebugBreak V8_FINAL : public HTemplateInstruction<0> {
  public:
-  virtual Representation RequiredInputRepresentation(int index) {
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     return Representation::None();
   }
 
   DECLARE_CONCRETE_INSTRUCTION(DebugBreak)
 };
 
 
-class HGoto: public HTemplateControlInstruction<1, 0> {
+class HGoto V8_FINAL : public HTemplateControlInstruction<1, 0> {
  public:
   explicit HGoto(HBasicBlock* target) {
     SetSuccessorAt(0, target);
   }
 
-  virtual Representation RequiredInputRepresentation(int index) {
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     return Representation::None();
   }
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
   DECLARE_CONCRETE_INSTRUCTION(Goto)
 };
 
 
-class HUnaryControlInstruction: public HTemplateControlInstruction<2, 1> {
+class HUnaryControlInstruction : public HTemplateControlInstruction<2, 1> {
  public:
   HUnaryControlInstruction(HValue* value,
                            HBasicBlock* true_target,
                            HBasicBlock* false_target) {
     SetOperandAt(0, value);
     SetSuccessorAt(0, true_target);
     SetSuccessorAt(1, false_target);
   }
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
   HValue* value() { return OperandAt(0); }
 };
 
 
-class HBranch: public HUnaryControlInstruction {
+class HBranch V8_FINAL : public HUnaryControlInstruction {
  public:
   HBranch(HValue* value,
           ToBooleanStub::Types expected_input_types = ToBooleanStub::Types(),
           HBasicBlock* true_target = NULL,
           HBasicBlock* false_target = NULL)
       : HUnaryControlInstruction(value, true_target, false_target),
         expected_input_types_(expected_input_types) {
     SetFlag(kAllowUndefinedAsNaN);
   }
 
-  virtual Representation RequiredInputRepresentation(int index) {
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     return Representation::None();
   }
-  virtual Representation observed_input_representation(int index);
+  virtual Representation observed_input_representation(int index) V8_OVERRIDE;
 
   ToBooleanStub::Types expected_input_types() const {
     return expected_input_types_;
   }
 
   DECLARE_CONCRETE_INSTRUCTION(Branch)
 
  private:
   ToBooleanStub::Types expected_input_types_;
 };
 
 
-class HCompareMap: public HUnaryControlInstruction {
+class HCompareMap V8_FINAL : public HUnaryControlInstruction {
  public:
   HCompareMap(HValue* value,
               Handle<Map> map,
               HBasicBlock* true_target = NULL,
               HBasicBlock* false_target = NULL)
       : HUnaryControlInstruction(value, true_target, false_target),
       map_(map) {
     ASSERT(!map.is_null());
   }
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
   Handle<Map> map() const { return map_; }
 
-  virtual Representation RequiredInputRepresentation(int index) {
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     return Representation::Tagged();
   }
 
   DECLARE_CONCRETE_INSTRUCTION(CompareMap)
 
  private:
   Handle<Map> map_;
 };
 
 
-class HContext: public HTemplateInstruction<0> {
+class HContext V8_FINAL : public HTemplateInstruction<0> {
  public:
   static HContext* New(Zone* zone) {
     return new(zone) HContext();
   }
 
-  virtual Representation RequiredInputRepresentation(int index) {
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     return Representation::None();
   }
 
   DECLARE_CONCRETE_INSTRUCTION(Context)
 
  protected:
-  virtual bool DataEquals(HValue* other) { return true; }
+  virtual bool DataEquals(HValue* other) V8_OVERRIDE { return true; }
 
  private:
   HContext() {
     set_representation(Representation::Tagged());
     SetFlag(kUseGVN);
   }
 
-  virtual bool IsDeletable() const { return true; }
+  virtual bool IsDeletable() const V8_OVERRIDE { return true; }
 };
 
 
-class HReturn: public HTemplateControlInstruction<0, 3> {
+class HReturn V8_FINAL : public HTemplateControlInstruction<0, 3> {
  public:
   static HInstruction* New(Zone* zone,
                            HValue* context,
                            HValue* value,
                            HValue* parameter_count) {
     return new(zone) HReturn(value, context, parameter_count);
   }
 
   static HInstruction* New(Zone* zone,
                            HValue* context,
                            HValue* value) {
     return new(zone) HReturn(value, context, 0);
   }
 
-  virtual Representation RequiredInputRepresentation(int index) {
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     return Representation::Tagged();
   }
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
   HValue* value() { return OperandAt(0); }
   HValue* context() { return OperandAt(1); }
   HValue* parameter_count() { return OperandAt(2); }
 
   DECLARE_CONCRETE_INSTRUCTION(Return)
 
  private:
   HReturn(HValue* value, HValue* context, HValue* parameter_count) {
     SetOperandAt(0, value);
     SetOperandAt(1, context);
     SetOperandAt(2, parameter_count);
   }
 };
 
 
-class HAbnormalExit: public HTemplateControlInstruction<0, 0> {
+class HAbnormalExit V8_FINAL : public HTemplateControlInstruction<0, 0> {
  public:
-  virtual Representation RequiredInputRepresentation(int index) {
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     return Representation::None();
   }
 
   DECLARE_CONCRETE_INSTRUCTION(AbnormalExit)
 };
 
 
-class HUnaryOperation: public HTemplateInstruction<1> {
+class HUnaryOperation : public HTemplateInstruction<1> {
  public:
   HUnaryOperation(HValue* value, HType type = HType::Tagged())
       : HTemplateInstruction<1>(type) {
     SetOperandAt(0, value);
   }
 
   static HUnaryOperation* cast(HValue* value) {
     return reinterpret_cast<HUnaryOperation*>(value);
   }
 
   HValue* value() const { return OperandAt(0); }
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 };
 
 
-class HThrow: public HTemplateInstruction<2> {
+class HThrow V8_FINAL : public HTemplateInstruction<2> {
  public:
   static HThrow* New(Zone* zone,
                      HValue* context,
                      HValue* value) {
     return new(zone) HThrow(context, value);
   }
 
-  virtual Representation RequiredInputRepresentation(int index) {
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     return Representation::Tagged();
   }
 
   HValue* context() { return OperandAt(0); }
   HValue* value() { return OperandAt(1); }
 
   DECLARE_CONCRETE_INSTRUCTION(Throw)
 
  private:
   HThrow(HValue* context, HValue* value) {
     SetOperandAt(0, context);
     SetOperandAt(1, value);
     SetAllSideEffects();
   }
 };
 
 
-class HUseConst: public HUnaryOperation {
+class HUseConst V8_FINAL : public HUnaryOperation {
  public:
   DECLARE_INSTRUCTION_FACTORY_P1(HUseConst, HValue*);
 
-  virtual Representation RequiredInputRepresentation(int index) {
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     return Representation::None();
   }
 
   DECLARE_CONCRETE_INSTRUCTION(UseConst)
 
  private:
     explicit HUseConst(HValue* old_value) : HUnaryOperation(old_value) { }
 };
 
 
-class HForceRepresentation: public HTemplateInstruction<1> {
+class HForceRepresentation V8_FINAL : public HTemplateInstruction<1> {
  public:
   DECLARE_INSTRUCTION_FACTORY_P2(HForceRepresentation, HValue*, Representation);
 
   HValue* value() { return OperandAt(0); }
 
-  virtual HValue* EnsureAndPropagateNotMinusZero(BitVector* visited);
+  virtual HValue* EnsureAndPropagateNotMinusZero(
+      BitVector* visited) V8_OVERRIDE;
 
-  virtual Representation RequiredInputRepresentation(int index) {
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     return representation();  // Same as the output representation.
   }
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
   DECLARE_CONCRETE_INSTRUCTION(ForceRepresentation)
 
  private:
   HForceRepresentation(HValue* value, Representation required_representation) {
     SetOperandAt(0, value);
     set_representation(required_representation);
   }
 };
 
 
-class HChange: public HUnaryOperation {
+class HChange V8_FINAL : public HUnaryOperation {
  public:
   HChange(HValue* value,
           Representation to,
           bool is_truncating_to_smi,
-          bool is_truncating_to_int32,
-          bool allow_undefined_as_nan)
+          bool is_truncating_to_int32)
       : HUnaryOperation(value) {
     ASSERT(!value->representation().IsNone());
     ASSERT(!to.IsNone());
     ASSERT(!value->representation().Equals(to));
     set_representation(to);
     SetFlag(kUseGVN);
-    if (allow_undefined_as_nan) SetFlag(kAllowUndefinedAsNaN);
     if (is_truncating_to_smi) SetFlag(kTruncatingToSmi);
     if (is_truncating_to_int32) SetFlag(kTruncatingToInt32);
     if (value->representation().IsSmi() || value->type().IsSmi()) {
       set_type(HType::Smi());
     } else {
       set_type(HType::TaggedNumber());
       if (to.IsTagged()) SetGVNFlag(kChangesNewSpacePromotion);
     }
   }
 
-  virtual HValue* EnsureAndPropagateNotMinusZero(BitVector* visited);
-  virtual HType CalculateInferredType();
-  virtual HValue* Canonicalize();
+  bool can_convert_undefined_to_nan() {
+    return CheckUsesForFlag(kAllowUndefinedAsNaN);
+  }
+
+  virtual HValue* EnsureAndPropagateNotMinusZero(
+      BitVector* visited) V8_OVERRIDE;
+  virtual HType CalculateInferredType() V8_OVERRIDE;
+  virtual HValue* Canonicalize() V8_OVERRIDE;
 
   Representation from() const { return value()->representation(); }
   Representation to() const { return representation(); }
-  bool allow_undefined_as_nan() const {
-    return CheckFlag(kAllowUndefinedAsNaN);
-  }
   bool deoptimize_on_minus_zero() const {
     return CheckFlag(kBailoutOnMinusZero);
   }
-  virtual Representation RequiredInputRepresentation(int index) {
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     return from();
   }
 
-  virtual Range* InferRange(Zone* zone);
+  virtual Range* InferRange(Zone* zone) V8_OVERRIDE;
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
   DECLARE_CONCRETE_INSTRUCTION(Change)
 
  protected:
-  virtual bool DataEquals(HValue* other) { return true; }
+  virtual bool DataEquals(HValue* other) V8_OVERRIDE { return true; }
 
  private:
-  virtual bool IsDeletable() const {
+  virtual bool IsDeletable() const V8_OVERRIDE {
     return !from().IsTagged() || value()->type().IsSmi();
   }
 };
 
 
-class HClampToUint8: public HUnaryOperation {
+class HClampToUint8 V8_FINAL : public HUnaryOperation {
  public:
   DECLARE_INSTRUCTION_FACTORY_P1(HClampToUint8, HValue*);
 
-  virtual Representation RequiredInputRepresentation(int index) {
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     return Representation::None();
   }
 
   DECLARE_CONCRETE_INSTRUCTION(ClampToUint8)
 
  protected:
-  virtual bool DataEquals(HValue* other) { return true; }
+  virtual bool DataEquals(HValue* other) V8_OVERRIDE { return true; }
 
  private:
   explicit HClampToUint8(HValue* value)
       : HUnaryOperation(value) {
     set_representation(Representation::Integer32());
     SetFlag(kAllowUndefinedAsNaN);
     SetFlag(kUseGVN);
   }
 
-  virtual bool IsDeletable() const { return true; }
+  virtual bool IsDeletable() const V8_OVERRIDE { return true; }
 };
 
 
 enum RemovableSimulate {
   REMOVABLE_SIMULATE,
   FIXED_SIMULATE
 };
 
 
-class HSimulate: public HInstruction {
+class HSimulate V8_FINAL : public HInstruction {
  public:
   HSimulate(BailoutId ast_id,
             int pop_count,
             Zone* zone,
             RemovableSimulate removable)
       : ast_id_(ast_id),
         pop_count_(pop_count),
         values_(2, zone),
         assigned_indexes_(2, zone),
         zone_(zone),
         removable_(removable) {}
-  virtual ~HSimulate() {}
+  ~HSimulate() {}
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
   bool HasAstId() const { return !ast_id_.IsNone(); }
   BailoutId ast_id() const { return ast_id_; }
   void set_ast_id(BailoutId id) {
     ASSERT(!HasAstId());
     ast_id_ = id;
   }
 
   int pop_count() const { return pop_count_; }
   const ZoneList<HValue*>* values() const { return &values_; }
   int GetAssignedIndexAt(int index) const {
     ASSERT(HasAssignedIndexAt(index));
     return assigned_indexes_[index];
   }
   bool HasAssignedIndexAt(int index) const {
     return assigned_indexes_[index] != kNoIndex;
   }
   void AddAssignedValue(int index, HValue* value) {
     AddValue(index, value);
   }
   void AddPushedValue(HValue* value) {
     AddValue(kNoIndex, value);
   }
   int ToOperandIndex(int environment_index) {
     for (int i = 0; i < assigned_indexes_.length(); ++i) {
       if (assigned_indexes_[i] == environment_index) return i;
     }
     return -1;
   }
-  virtual int OperandCount() { return values_.length(); }
-  virtual HValue* OperandAt(int index) const { return values_[index]; }
+  virtual int OperandCount() V8_OVERRIDE { return values_.length(); }
+  virtual HValue* OperandAt(int index) const V8_OVERRIDE {
+    return values_[index];
+  }
 
-  virtual bool HasEscapingOperandAt(int index) { return false; }
-  virtual Representation RequiredInputRepresentation(int index) {
+  virtual bool HasEscapingOperandAt(int index) V8_OVERRIDE { return false; }
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     return Representation::None();
   }
 
   void MergeWith(ZoneList<HSimulate*>* list);
   bool is_candidate_for_removal() { return removable_ == REMOVABLE_SIMULATE; }
 
   DECLARE_CONCRETE_INSTRUCTION(Simulate)
 
 #ifdef DEBUG
-  virtual void Verify();
+  virtual void Verify() V8_OVERRIDE;
   void set_closure(Handle<JSFunction> closure) { closure_ = closure; }
   Handle<JSFunction> closure() const { return closure_; }
 #endif
 
  protected:
-  virtual void InternalSetOperandAt(int index, HValue* value) {
+  virtual void InternalSetOperandAt(int index, HValue* value) V8_OVERRIDE {
     values_[index] = value;
   }
 
  private:
   static const int kNoIndex = -1;
   void AddValue(int index, HValue* value) {
     assigned_indexes_.Add(index, zone_);
     // Resize the list of pushed values.
     values_.Add(NULL, zone_);
     // Set the operand through the base method in HValue to make sure that the
@@ skipping 12 matching lines @@
   ZoneList<int> assigned_indexes_;
   Zone* zone_;
   RemovableSimulate removable_;
 
 #ifdef DEBUG
   Handle<JSFunction> closure_;
 #endif
 };
 
 
-class HEnvironmentMarker: public HTemplateInstruction<1> {
+class HEnvironmentMarker V8_FINAL : public HTemplateInstruction<1> {
  public:
   enum Kind { BIND, LOOKUP };
 
   HEnvironmentMarker(Kind kind, int index)
       : kind_(kind), index_(index), next_simulate_(NULL) { }
 
   Kind kind() { return kind_; }
   int index() { return index_; }
   HSimulate* next_simulate() { return next_simulate_; }
   void set_next_simulate(HSimulate* simulate) {
     next_simulate_ = simulate;
   }
 
-  virtual Representation RequiredInputRepresentation(int index) {
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     return Representation::None();
   }
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
 #ifdef DEBUG
   void set_closure(Handle<JSFunction> closure) {
     ASSERT(closure_.is_null());
     ASSERT(!closure.is_null());
     closure_ = closure;
   }
   Handle<JSFunction> closure() const { return closure_; }
 #endif
 
   DECLARE_CONCRETE_INSTRUCTION(EnvironmentMarker);
 
  private:
   Kind kind_;
   int index_;
   HSimulate* next_simulate_;
 
 #ifdef DEBUG
   Handle<JSFunction> closure_;
 #endif
 };
 
 
-class HStackCheck: public HTemplateInstruction<1> {
+class HStackCheck V8_FINAL : public HTemplateInstruction<1> {
  public:
   enum Type {
     kFunctionEntry,
     kBackwardsBranch
   };
 
   DECLARE_INSTRUCTION_FACTORY_P2(HStackCheck, HValue*, Type);
 
   HValue* context() { return OperandAt(0); }
 
-  virtual Representation RequiredInputRepresentation(int index) {
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     return Representation::Tagged();
   }
 
   void Eliminate() {
     // The stack check eliminator might try to eliminate the same stack
     // check instruction multiple times.
     if (IsLinked()) {
       DeleteAndReplaceWith(NULL);
     }
   }
@@ skipping 18 matching lines @@
   DROP_EXTRA_ON_RETURN,   // Drop an extra value from the environment on return.
   CONSTRUCT_CALL_RETURN,  // Either use allocated receiver or return value.
   GETTER_CALL_RETURN,     // Returning from a getter, need to restore context.
   SETTER_CALL_RETURN      // Use the RHS of the assignment as the return value.
 };
 
 
 class HArgumentsObject;
 
 
-class HEnterInlined: public HTemplateInstruction<0> {
+class HEnterInlined V8_FINAL : public HTemplateInstruction<0> {
  public:
   static HEnterInlined* New(Zone* zone,
                             HValue* context,
                             Handle<JSFunction> closure,
                             int arguments_count,
                             FunctionLiteral* function,
                             InliningKind inlining_kind,
                             Variable* arguments_var,
                             HArgumentsObject* arguments_object,
                             bool undefined_receiver) {
     return new(zone) HEnterInlined(closure, arguments_count, function,
                                    inlining_kind, arguments_var,
                                    arguments_object, undefined_receiver, zone);
   }
 
   void RegisterReturnTarget(HBasicBlock* return_target, Zone* zone);
   ZoneList<HBasicBlock*>* return_targets() { return &return_targets_; }
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
   Handle<JSFunction> closure() const { return closure_; }
   int arguments_count() const { return arguments_count_; }
   bool arguments_pushed() const { return arguments_pushed_; }
   void set_arguments_pushed() { arguments_pushed_ = true; }
   FunctionLiteral* function() const { return function_; }
   InliningKind inlining_kind() const { return inlining_kind_; }
   bool undefined_receiver() const { return undefined_receiver_; }
 
-  virtual Representation RequiredInputRepresentation(int index) {
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     return Representation::None();
   }
 
   Variable* arguments_var() { return arguments_var_; }
   HArgumentsObject* arguments_object() { return arguments_object_; }
 
   DECLARE_CONCRETE_INSTRUCTION(EnterInlined)
 
  private:
   HEnterInlined(Handle<JSFunction> closure,
@@ skipping 20 matching lines @@
   bool arguments_pushed_;
   FunctionLiteral* function_;
   InliningKind inlining_kind_;
   Variable* arguments_var_;
   HArgumentsObject* arguments_object_;
   bool undefined_receiver_;
   ZoneList<HBasicBlock*> return_targets_;
 };
 
 
-class HLeaveInlined: public HTemplateInstruction<0> {
+class HLeaveInlined V8_FINAL : public HTemplateInstruction<0> {
  public:
   HLeaveInlined() { }
 
-  virtual Representation RequiredInputRepresentation(int index) {
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     return Representation::None();
   }
 
   DECLARE_CONCRETE_INSTRUCTION(LeaveInlined)
 };
 
 
-class HPushArgument: public HUnaryOperation {
+class HPushArgument V8_FINAL : public HUnaryOperation {
  public:
   DECLARE_INSTRUCTION_FACTORY_P1(HPushArgument, HValue*);
 
-  virtual Representation RequiredInputRepresentation(int index) {
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     return Representation::Tagged();
   }
 
   HValue* argument() { return OperandAt(0); }
 
   DECLARE_CONCRETE_INSTRUCTION(PushArgument)
 
  private:
   explicit HPushArgument(HValue* value) : HUnaryOperation(value) {
     set_representation(Representation::Tagged());
   }
 };
 
 
-class HThisFunction: public HTemplateInstruction<0> {
+class HThisFunction V8_FINAL : public HTemplateInstruction<0> {
  public:
   HThisFunction() {
     set_representation(Representation::Tagged());
     SetFlag(kUseGVN);
   }
 
-  virtual Representation RequiredInputRepresentation(int index) {
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     return Representation::None();
   }
 
   DECLARE_CONCRETE_INSTRUCTION(ThisFunction)
 
  protected:
-  virtual bool DataEquals(HValue* other) { return true; }
+  virtual bool DataEquals(HValue* other) V8_OVERRIDE { return true; }
 
  private:
-  virtual bool IsDeletable() const { return true; }
+  virtual bool IsDeletable() const V8_OVERRIDE { return true; }
 };
 
 
-class HOuterContext: public HUnaryOperation {
+class HOuterContext V8_FINAL : public HUnaryOperation {
  public:
   DECLARE_INSTRUCTION_FACTORY_P1(HOuterContext, HValue*);
 
   DECLARE_CONCRETE_INSTRUCTION(OuterContext);
 
-  virtual Representation RequiredInputRepresentation(int index) {
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     return Representation::Tagged();
   }
 
  protected:
-  virtual bool DataEquals(HValue* other) { return true; }
+  virtual bool DataEquals(HValue* other) V8_OVERRIDE { return true; }
 
  private:
   explicit HOuterContext(HValue* inner) : HUnaryOperation(inner) {
     set_representation(Representation::Tagged());
     SetFlag(kUseGVN);
   }
 
-  virtual bool IsDeletable() const { return true; }
+  virtual bool IsDeletable() const V8_OVERRIDE { return true; }
 };
 
 
-class HDeclareGlobals: public HUnaryOperation {
+class HDeclareGlobals V8_FINAL : public HUnaryOperation {
  public:
   HDeclareGlobals(HValue* context,
                   Handle<FixedArray> pairs,
                   int flags)
       : HUnaryOperation(context),
         pairs_(pairs),
         flags_(flags) {
     set_representation(Representation::Tagged());
     SetAllSideEffects();
   }
 
   static HDeclareGlobals* New(Zone* zone,
                               HValue* context,
                               Handle<FixedArray> pairs,
                               int flags) {
     return new(zone) HDeclareGlobals(context, pairs, flags);
   }
 
   HValue* context() { return OperandAt(0); }
   Handle<FixedArray> pairs() const { return pairs_; }
   int flags() const { return flags_; }
 
   DECLARE_CONCRETE_INSTRUCTION(DeclareGlobals)
 
-  virtual Representation RequiredInputRepresentation(int index) {
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     return Representation::Tagged();
   }
 
  private:
   Handle<FixedArray> pairs_;
   int flags_;
 };
 
 
-class HGlobalObject: public HUnaryOperation {
+class HGlobalObject V8_FINAL : public HUnaryOperation {
  public:
   explicit HGlobalObject(HValue* context) : HUnaryOperation(context) {
     set_representation(Representation::Tagged());
     SetFlag(kUseGVN);
   }
 
   static HGlobalObject* New(Zone* zone, HValue* context) {
     return new(zone) HGlobalObject(context);
   }
 
   DECLARE_CONCRETE_INSTRUCTION(GlobalObject)
 
-  virtual Representation RequiredInputRepresentation(int index) {
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     return Representation::Tagged();
   }
 
  protected:
-  virtual bool DataEquals(HValue* other) { return true; }
+  virtual bool DataEquals(HValue* other) V8_OVERRIDE { return true; }
 
  private:
-  virtual bool IsDeletable() const { return true; }
+  virtual bool IsDeletable() const V8_OVERRIDE { return true; }
 };
 
 
-class HGlobalReceiver: public HUnaryOperation {
+class HGlobalReceiver V8_FINAL : public HUnaryOperation {
  public:
   DECLARE_INSTRUCTION_FACTORY_P1(HGlobalReceiver, HValue*);
 
   DECLARE_CONCRETE_INSTRUCTION(GlobalReceiver)
 
-  virtual Representation RequiredInputRepresentation(int index) {
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     return Representation::Tagged();
   }
 
  protected:
-  virtual bool DataEquals(HValue* other) { return true; }
+  virtual bool DataEquals(HValue* other) V8_OVERRIDE { return true; }
 
  private:
   explicit HGlobalReceiver(HValue* global_object)
       : HUnaryOperation(global_object) {
     set_representation(Representation::Tagged());
     SetFlag(kUseGVN);
   }
 
-  virtual bool IsDeletable() const { return true; }
+  virtual bool IsDeletable() const V8_OVERRIDE { return true; }
 };
 
 
 template <int V>
-class HCall: public HTemplateInstruction<V> {
+class HCall : public HTemplateInstruction<V> {
  public:
   // The argument count includes the receiver.
   explicit HCall<V>(int argument_count) : argument_count_(argument_count) {
     this->set_representation(Representation::Tagged());
     this->SetAllSideEffects();
   }
 
-  virtual HType CalculateInferredType() { return HType::Tagged(); }
+  virtual HType CalculateInferredType() V8_FINAL V8_OVERRIDE {
+    return HType::Tagged();
+  }
 
   virtual int argument_count() const { return argument_count_; }
 
-  virtual bool IsCall() { return true; }
+  virtual bool IsCall() V8_FINAL V8_OVERRIDE { return true; }
 
  private:
   int argument_count_;
 };
 
 
-class HUnaryCall: public HCall<1> {
+class HUnaryCall : public HCall<1> {
  public:
   HUnaryCall(HValue* value, int argument_count)
       : HCall<1>(argument_count) {
     SetOperandAt(0, value);
   }
 
-  virtual Representation RequiredInputRepresentation(int index) {
+  virtual Representation RequiredInputRepresentation(
+      int index) V8_FINAL V8_OVERRIDE {
     return Representation::Tagged();
   }
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
   HValue* value() { return OperandAt(0); }
 };
 
 
-class HBinaryCall: public HCall<2> {
+class HBinaryCall : public HCall<2> {
  public:
   HBinaryCall(HValue* first, HValue* second, int argument_count)
       : HCall<2>(argument_count) {
     SetOperandAt(0, first);
     SetOperandAt(1, second);
   }
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
-  virtual Representation RequiredInputRepresentation(int index) {
+  virtual Representation RequiredInputRepresentation(
+      int index) V8_FINAL V8_OVERRIDE {
     return Representation::Tagged();
   }
 
   HValue* first() { return OperandAt(0); }
   HValue* second() { return OperandAt(1); }
 };
 
 
-class HInvokeFunction: public HBinaryCall {
+class HInvokeFunction V8_FINAL : public HBinaryCall {
  public:
   HInvokeFunction(HValue* context, HValue* function, int argument_count)
       : HBinaryCall(context, function, argument_count) {
   }
 
   static HInvokeFunction* New(Zone* zone,
                               HValue* context,
                               HValue* function,
                               int argument_count) {
     return new(zone) HInvokeFunction(context, function, argument_count);
@@ skipping 11 matching lines @@
 
   static HInvokeFunction* New(Zone* zone,
                               HValue* context,
                               HValue* function,
                               Handle<JSFunction> known_function,
                               int argument_count) {
     return new(zone) HInvokeFunction(context, function,
                                      known_function, argument_count);
   }
 
-  virtual Representation RequiredInputRepresentation(int index) {
-    return Representation::Tagged();
-  }
-
   HValue* context() { return first(); }
   HValue* function() { return second(); }
   Handle<JSFunction> known_function() { return known_function_; }
   int formal_parameter_count() const { return formal_parameter_count_; }
 
   DECLARE_CONCRETE_INSTRUCTION(InvokeFunction)
 
  private:
   Handle<JSFunction> known_function_;
   int formal_parameter_count_;
 };
 
 
-class HCallConstantFunction: public HCall<0> {
+class HCallConstantFunction V8_FINAL : public HCall<0> {
  public:
   HCallConstantFunction(Handle<JSFunction> function, int argument_count)
       : HCall<0>(argument_count),
         function_(function),
         formal_parameter_count_(function->shared()->formal_parameter_count()) {}
 
   Handle<JSFunction> function() const { return function_; }
   int formal_parameter_count() const { return formal_parameter_count_; }
 
   bool IsApplyFunction() const {
     return function_->code() ==
         Isolate::Current()->builtins()->builtin(Builtins::kFunctionApply);
   }
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
-  virtual Representation RequiredInputRepresentation(int index) {
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     return Representation::None();
   }
 
   DECLARE_CONCRETE_INSTRUCTION(CallConstantFunction)
 
  private:
   Handle<JSFunction> function_;
   int formal_parameter_count_;
 };
 
 
-class HCallKeyed: public HBinaryCall {
+class HCallKeyed V8_FINAL : public HBinaryCall {
  public:
   HCallKeyed(HValue* context, HValue* key, int argument_count)
       : HBinaryCall(context, key, argument_count) {
   }
 
-  virtual Representation RequiredInputRepresentation(int index) {
-    return Representation::Tagged();
-  }
-
   HValue* context() { return first(); }
   HValue* key() { return second(); }
 
   DECLARE_CONCRETE_INSTRUCTION(CallKeyed)
 };
 
 
-class HCallNamed: public HUnaryCall {
+class HCallNamed V8_FINAL : public HUnaryCall {
  public:
   HCallNamed(HValue* context, Handle<String> name, int argument_count)
       : HUnaryCall(context, argument_count), name_(name) {
   }
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
   HValue* context() { return value(); }
   Handle<String> name() const { return name_; }
 
   DECLARE_CONCRETE_INSTRUCTION(CallNamed)
 
-  virtual Representation RequiredInputRepresentation(int index) {
-    return Representation::Tagged();
-  }
-
  private:
   Handle<String> name_;
 };
 
 
-class HCallFunction: public HBinaryCall {
+class HCallFunction V8_FINAL : public HBinaryCall {
  public:
   HCallFunction(HValue* context, HValue* function, int argument_count)
       : HBinaryCall(context, function, argument_count) {
   }
 
   static HCallFunction* New(Zone* zone,
                             HValue* context,
                             HValue* function,
                             int argument_count) {
     return new(zone) HCallFunction(context, function, argument_count);
   }
 
   HValue* context() { return first(); }
   HValue* function() { return second(); }
 
-  virtual Representation RequiredInputRepresentation(int index) {
-    return Representation::Tagged();
-  }
-
   DECLARE_CONCRETE_INSTRUCTION(CallFunction)
 };
 
 
-class HCallGlobal: public HUnaryCall {
+class HCallGlobal V8_FINAL : public HUnaryCall {
  public:
   HCallGlobal(HValue* context, Handle<String> name, int argument_count)
       : HUnaryCall(context, argument_count), name_(name) {
   }
 
   static HCallGlobal* New(Zone* zone,
                           HValue* context,
                           Handle<String> name,
                           int argument_count) {
     return new(zone) HCallGlobal(context, name, argument_count);
   }
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
   HValue* context() { return value(); }
   Handle<String> name() const { return name_; }
 
-  virtual Representation RequiredInputRepresentation(int index) {
-    return Representation::Tagged();
-  }
-
   DECLARE_CONCRETE_INSTRUCTION(CallGlobal)
 
  private:
   Handle<String> name_;
 };
 
 
-class HCallKnownGlobal: public HCall<0> {
+class HCallKnownGlobal V8_FINAL : public HCall<0> {
  public:
   HCallKnownGlobal(Handle<JSFunction> target, int argument_count)
       : HCall<0>(argument_count),
         target_(target),
         formal_parameter_count_(target->shared()->formal_parameter_count()) { }
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
   Handle<JSFunction> target() const { return target_; }
   int formal_parameter_count() const { return formal_parameter_count_; }
 
-  virtual Representation RequiredInputRepresentation(int index) {
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     return Representation::None();
   }
 
   DECLARE_CONCRETE_INSTRUCTION(CallKnownGlobal)
 
  private:
   Handle<JSFunction> target_;
   int formal_parameter_count_;
 };
 
 
-class HCallNew: public HBinaryCall {
+class HCallNew V8_FINAL : public HBinaryCall {
  public:
   HCallNew(HValue* context, HValue* constructor, int argument_count)
-      : HBinaryCall(context, constructor, argument_count) {
-  }
-
-  virtual Representation RequiredInputRepresentation(int index) {
-    return Representation::Tagged();
-  }
+      : HBinaryCall(context, constructor, argument_count) {}
 
   HValue* context() { return first(); }
   HValue* constructor() { return second(); }
 
   DECLARE_CONCRETE_INSTRUCTION(CallNew)
 };
 
 
-class HCallNewArray: public HCallNew {
+class HCallNewArray V8_FINAL : public HBinaryCall {
  public:
   HCallNewArray(HValue* context, HValue* constructor, int argument_count,
                 Handle<Cell> type_cell, ElementsKind elements_kind)
-      : HCallNew(context, constructor, argument_count),
+      : HBinaryCall(context, constructor, argument_count),
         elements_kind_(elements_kind),
         type_cell_(type_cell) {}
 
-  virtual void PrintDataTo(StringStream* stream);
+  HValue* context() { return first(); }
+  HValue* constructor() { return second(); }
+
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
   Handle<Cell> property_cell() const {
     return type_cell_;
   }
 
   ElementsKind elements_kind() const { return elements_kind_; }
 
   DECLARE_CONCRETE_INSTRUCTION(CallNewArray)
 
  private:
   ElementsKind elements_kind_;
   Handle<Cell> type_cell_;
 };
 
 
-class HCallRuntime: public HCall<1> {
+class HCallRuntime V8_FINAL : public HCall<1> {
  public:
   static HCallRuntime* New(Zone* zone,
                            HValue* context,
                            Handle<String> name,
                            const Runtime::Function* c_function,
                            int argument_count) {
     return new(zone) HCallRuntime(context, name, c_function, argument_count);
   }
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
   HValue* context() { return OperandAt(0); }
   const Runtime::Function* function() const { return c_function_; }
   Handle<String> name() const { return name_; }
 
-  virtual Representation RequiredInputRepresentation(int index) {
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     return Representation::Tagged();
   }
 
   DECLARE_CONCRETE_INSTRUCTION(CallRuntime)
 
  private:
   HCallRuntime(HValue* context,
                Handle<String> name,
                const Runtime::Function* c_function,
                int argument_count)
       : HCall<1>(argument_count), c_function_(c_function), name_(name) {
     SetOperandAt(0, context);
   }
 
   const Runtime::Function* c_function_;
   Handle<String> name_;
 };
 
 
-class HMapEnumLength: public HUnaryOperation {
+class HMapEnumLength V8_FINAL : public HUnaryOperation {
  public:
   DECLARE_INSTRUCTION_FACTORY_P1(HMapEnumLength, HValue*);
 
-  virtual Representation RequiredInputRepresentation(int index) {
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     return Representation::Tagged();
   }
 
   DECLARE_CONCRETE_INSTRUCTION(MapEnumLength)
 
  protected:
-  virtual bool DataEquals(HValue* other) { return true; }
+  virtual bool DataEquals(HValue* other) V8_OVERRIDE { return true; }
 
  private:
   explicit HMapEnumLength(HValue* value)
       : HUnaryOperation(value, HType::Smi()) {
     set_representation(Representation::Smi());
     SetFlag(kUseGVN);
     SetGVNFlag(kDependsOnMaps);
   }
 
-  virtual bool IsDeletable() const { return true; }
+  virtual bool IsDeletable() const V8_OVERRIDE { return true; }
 };
 
 
-class HElementsKind: public HUnaryOperation {
+class HElementsKind V8_FINAL : public HUnaryOperation {
  public:
   explicit HElementsKind(HValue* value) : HUnaryOperation(value) {
     set_representation(Representation::Integer32());
     SetFlag(kUseGVN);
     SetGVNFlag(kDependsOnElementsKind);
   }
 
-  virtual Representation RequiredInputRepresentation(int index) {
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     return Representation::Tagged();
   }
 
   DECLARE_CONCRETE_INSTRUCTION(ElementsKind)
 
  protected:
-  virtual bool DataEquals(HValue* other) { return true; }
+  virtual bool DataEquals(HValue* other) V8_OVERRIDE { return true; }
 
  private:
-  virtual bool IsDeletable() const { return true; }
+  virtual bool IsDeletable() const V8_OVERRIDE { return true; }
 };
 
 
-class HUnaryMathOperation: public HTemplateInstruction<2> {
+class HUnaryMathOperation V8_FINAL : public HTemplateInstruction<2> {
  public:
   static HInstruction* New(Zone* zone,
                            HValue* context,
                            HValue* value,
                            BuiltinFunctionId op);
 
   HValue* context() { return OperandAt(0); }
   HValue* value() { return OperandAt(1); }
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
-  virtual HValue* EnsureAndPropagateNotMinusZero(BitVector* visited);
+  virtual HValue* EnsureAndPropagateNotMinusZero(
+      BitVector* visited) V8_OVERRIDE;
 
-  virtual Representation RequiredInputRepresentation(int index) {
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     if (index == 0) {
       return Representation::Tagged();
     } else {
       switch (op_) {
         case kMathFloor:
         case kMathRound:
         case kMathSqrt:
         case kMathPowHalf:
         case kMathLog:
         case kMathExp:
         case kMathSin:
         case kMathCos:
         case kMathTan:
           return Representation::Double();
         case kMathAbs:
           return representation();
         default:
           UNREACHABLE();
           return Representation::None();
       }
     }
   }
 
-  virtual Range* InferRange(Zone* zone);
+  virtual Range* InferRange(Zone* zone) V8_OVERRIDE;
 
-  virtual HValue* Canonicalize();
-  virtual Representation RepresentationFromInputs();
+  virtual HValue* Canonicalize() V8_OVERRIDE;
+  virtual Representation RepresentationFromInputs() V8_OVERRIDE;
 
   BuiltinFunctionId op() const { return op_; }
   const char* OpName() const;
 
   DECLARE_CONCRETE_INSTRUCTION(UnaryMathOperation)
 
  protected:
-  virtual bool DataEquals(HValue* other) {
+  virtual bool DataEquals(HValue* other) V8_OVERRIDE {
     HUnaryMathOperation* b = HUnaryMathOperation::cast(other);
     return op_ == b->op();
   }
 
  private:
   HUnaryMathOperation(HValue* context, HValue* value, BuiltinFunctionId op)
       : HTemplateInstruction<2>(HType::TaggedNumber()), op_(op) {
     SetOperandAt(0, context);
     SetOperandAt(1, value);
     switch (op) {
       case kMathFloor:
       case kMathRound:
-        // TODO(verwaest): Set representation to flexible int starting as smi.
         set_representation(Representation::Integer32());
         break;
       case kMathAbs:
         // Not setting representation here: it is None intentionally.
         SetFlag(kFlexibleRepresentation);
         // TODO(svenpanne) This flag is actually only needed if representation()
         // is tagged, and not when it is an unboxed double or unboxed integer.
         SetGVNFlag(kChangesNewSpacePromotion);
         break;
       case kMathLog:
       case kMathSin:
       case kMathCos:
       case kMathTan:
         set_representation(Representation::Double());
         // These operations use the TranscendentalCache, so they may allocate.
         SetGVNFlag(kChangesNewSpacePromotion);
         break;
       case kMathExp:
       case kMathSqrt:
       case kMathPowHalf:
         set_representation(Representation::Double());
         break;
       default:
         UNREACHABLE();
     }
     SetFlag(kUseGVN);
     SetFlag(kAllowUndefinedAsNaN);
   }
 
-  virtual bool IsDeletable() const { return true; }
+  virtual bool IsDeletable() const V8_OVERRIDE { return true; }
 
   BuiltinFunctionId op_;
 };
 
 
-class HLoadExternalArrayPointer: public HUnaryOperation {
+class HLoadExternalArrayPointer V8_FINAL : public HUnaryOperation {
  public:
   DECLARE_INSTRUCTION_FACTORY_P1(HLoadExternalArrayPointer, HValue*);
 
-  virtual Representation RequiredInputRepresentation(int index) {
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     return Representation::Tagged();
   }
 
-  virtual HType CalculateInferredType() {
+  virtual HType CalculateInferredType() V8_OVERRIDE {
     return HType::None();
   }
 
   DECLARE_CONCRETE_INSTRUCTION(LoadExternalArrayPointer)
 
  protected:
-  virtual bool DataEquals(HValue* other) { return true; }
+  virtual bool DataEquals(HValue* other) V8_OVERRIDE { return true; }
 
  private:
   explicit HLoadExternalArrayPointer(HValue* value)
       : HUnaryOperation(value) {
     set_representation(Representation::External());
     // The result of this instruction is idempotent as long as its inputs don't
     // change.  The external array of a specialized array elements object cannot
     // change once set, so it's no necessary to introduce any additional
     // dependencies on top of the inputs.
     SetFlag(kUseGVN);
   }
 
-  virtual bool IsDeletable() const { return true; }
+  virtual bool IsDeletable() const V8_OVERRIDE { return true; }
 };
 
 
-class HCheckMaps: public HTemplateInstruction<2> {
+class HCheckMaps V8_FINAL : public HTemplateInstruction<2> {
  public:
   static HCheckMaps* New(Zone* zone, HValue* context, HValue* value,
                          Handle<Map> map, CompilationInfo* info,
                          HValue *typecheck = NULL);
   static HCheckMaps* New(Zone* zone, HValue* context,
                          HValue* value, SmallMapList* maps,
                          HValue *typecheck = NULL) {
     HCheckMaps* check_map = new(zone) HCheckMaps(value, zone, typecheck);
     for (int i = 0; i < maps->length(); i++) {
-      check_map->map_set_.Add(maps->at(i), zone);
-      check_map->has_migration_target_ |= maps->at(i)->is_migration_target();
+      check_map->Add(maps->at(i), zone);
     }
     check_map->map_set_.Sort();
     return check_map;
   }
 
   bool CanOmitMapChecks() { return omit_; }
 
-  virtual bool HasEscapingOperandAt(int index) { return false; }
-  virtual Representation RequiredInputRepresentation(int index) {
+  virtual bool HasEscapingOperandAt(int index) V8_OVERRIDE { return false; }
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     return Representation::Tagged();
   }
   virtual void HandleSideEffectDominator(GVNFlag side_effect,
-                                         HValue* dominator);
-  virtual void PrintDataTo(StringStream* stream);
+                                         HValue* dominator) V8_OVERRIDE;
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
   HValue* value() { return OperandAt(0); }
   SmallMapList* map_set() { return &map_set_; }
 
   bool has_migration_target() {
     return has_migration_target_;
   }
 
-  virtual void FinalizeUniqueValueId();
+  virtual void FinalizeUniqueValueId() V8_OVERRIDE;
 
   DECLARE_CONCRETE_INSTRUCTION(CheckMaps)
 
  protected:
-  virtual bool DataEquals(HValue* other) {
+  virtual bool DataEquals(HValue* other) V8_OVERRIDE {
     ASSERT_EQ(map_set_.length(), map_unique_ids_.length());
     HCheckMaps* b = HCheckMaps::cast(other);
     // Relies on the fact that map_set has been sorted before.
     if (map_unique_ids_.length() != b->map_unique_ids_.length()) {
       return false;
     }
     for (int i = 0; i < map_unique_ids_.length(); i++) {
       if (map_unique_ids_.at(i) != b->map_unique_ids_.at(i)) {
         return false;
       }
     }
     return true;
   }
 
  private:
+  void Add(Handle<Map> map, Zone* zone) {
+    map_set_.Add(map, zone);
+    if (!has_migration_target_ && map->is_migration_target()) {
+      has_migration_target_ = true;
+      SetGVNFlag(kChangesNewSpacePromotion);
+    }
+  }
+
   // Clients should use one of the static New* methods above.
   HCheckMaps(HValue* value, Zone *zone, HValue* typecheck)
       : HTemplateInstruction<2>(value->type()),
         omit_(false), has_migration_target_(false), map_unique_ids_(0, zone) {
     SetOperandAt(0, value);
     // Use the object value for the dependency if NULL is passed.
     // TODO(titzer): do GVN flags already express this dependency?
     SetOperandAt(1, typecheck != NULL ? typecheck : value);
     set_representation(Representation::Tagged());
     SetFlag(kUseGVN);
@@ skipping 11 matching lines @@
     }
   }
 
   bool omit_;
   bool has_migration_target_;
   SmallMapList map_set_;
   ZoneList<UniqueValueId> map_unique_ids_;
 };
 
 
-class HCheckFunction: public HUnaryOperation {
+class HCheckFunction V8_FINAL : public HUnaryOperation {
  public:
   DECLARE_INSTRUCTION_FACTORY_P2(HCheckFunction, HValue*, Handle<JSFunction>);
 
-  virtual Representation RequiredInputRepresentation(int index) {
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     return Representation::Tagged();
   }
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
-  virtual HValue* Canonicalize();
+  virtual HValue* Canonicalize() V8_OVERRIDE;
 
 #ifdef DEBUG
-  virtual void Verify();
+  virtual void Verify() V8_OVERRIDE;
 #endif
 
-  virtual void FinalizeUniqueValueId() {
+  virtual void FinalizeUniqueValueId() V8_OVERRIDE {
     target_unique_id_ = UniqueValueId(target_);
   }
 
   Handle<JSFunction> target() const { return target_; }
   bool target_in_new_space() const { return target_in_new_space_; }
 
   DECLARE_CONCRETE_INSTRUCTION(CheckFunction)
 
  protected:
-  virtual bool DataEquals(HValue* other) {
+  virtual bool DataEquals(HValue* other) V8_OVERRIDE {
     HCheckFunction* b = HCheckFunction::cast(other);
     return target_unique_id_ == b->target_unique_id_;
   }
 
  private:
   HCheckFunction(HValue* value, Handle<JSFunction> function)
       : HUnaryOperation(value, value->type()),
         target_(function), target_unique_id_() {
     set_representation(Representation::Tagged());
     SetFlag(kUseGVN);
     target_in_new_space_ = Isolate::Current()->heap()->InNewSpace(*function);
   }
 
   Handle<JSFunction> target_;
   UniqueValueId target_unique_id_;
   bool target_in_new_space_;
 };
 
 
-class HCheckInstanceType: public HUnaryOperation {
+class HCheckInstanceType V8_FINAL : public HUnaryOperation {
  public:
   static HCheckInstanceType* NewIsSpecObject(HValue* value, Zone* zone) {
     return new(zone) HCheckInstanceType(value, IS_SPEC_OBJECT);
   }
   static HCheckInstanceType* NewIsJSArray(HValue* value, Zone* zone) {
     return new(zone) HCheckInstanceType(value, IS_JS_ARRAY);
   }
   static HCheckInstanceType* NewIsString(HValue* value, Zone* zone) {
     return new(zone) HCheckInstanceType(value, IS_STRING);
   }
   static HCheckInstanceType* NewIsInternalizedString(
       HValue* value, Zone* zone) {
     return new(zone) HCheckInstanceType(value, IS_INTERNALIZED_STRING);
   }
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
-  virtual Representation RequiredInputRepresentation(int index) {
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     return Representation::Tagged();
   }
 
-  virtual HValue* Canonicalize();
+  virtual HValue* Canonicalize() V8_OVERRIDE;
 
   bool is_interval_check() const { return check_ <= LAST_INTERVAL_CHECK; }
   void GetCheckInterval(InstanceType* first, InstanceType* last);
   void GetCheckMaskAndTag(uint8_t* mask, uint8_t* tag);
 
   DECLARE_CONCRETE_INSTRUCTION(CheckInstanceType)
 
  protected:
   // TODO(ager): It could be nice to allow the ommision of instance
   // type checks if we have already performed an instance type check
   // with a larger range.
-  virtual bool DataEquals(HValue* other) {
+  virtual bool DataEquals(HValue* other) V8_OVERRIDE {
     HCheckInstanceType* b = HCheckInstanceType::cast(other);
     return check_ == b->check_;
   }
 
  private:
   enum Check {
     IS_SPEC_OBJECT,
     IS_JS_ARRAY,
     IS_STRING,
     IS_INTERNALIZED_STRING,
     LAST_INTERVAL_CHECK = IS_JS_ARRAY
   };
 
   const char* GetCheckName();
 
   HCheckInstanceType(HValue* value, Check check)
       : HUnaryOperation(value), check_(check) {
     set_representation(Representation::Tagged());
     SetFlag(kUseGVN);
   }
 
   const Check check_;
 };
 
 
-class HCheckSmi: public HUnaryOperation {
+class HCheckSmi V8_FINAL : public HUnaryOperation {
  public:
   DECLARE_INSTRUCTION_FACTORY_P1(HCheckSmi, HValue*);
 
-  virtual Representation RequiredInputRepresentation(int index) {
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     return Representation::Tagged();
   }
 
-  virtual HValue* Canonicalize() {
+  virtual HValue* Canonicalize() V8_OVERRIDE {
     HType value_type = value()->type();
     if (value_type.IsSmi()) {
       return NULL;
     }
     return this;
   }
 
   DECLARE_CONCRETE_INSTRUCTION(CheckSmi)
 
  protected:
-  virtual bool DataEquals(HValue* other) { return true; }
+  virtual bool DataEquals(HValue* other) V8_OVERRIDE { return true; }
 
  private:
   explicit HCheckSmi(HValue* value) : HUnaryOperation(value, HType::Smi()) {
     set_representation(Representation::Smi());
     SetFlag(kUseGVN);
   }
 };
 
 
-class HIsNumberAndBranch: public HUnaryControlInstruction {
+class HIsNumberAndBranch V8_FINAL : public HUnaryControlInstruction {
  public:
   explicit HIsNumberAndBranch(HValue* value)
     : HUnaryControlInstruction(value, NULL, NULL) {
     SetFlag(kFlexibleRepresentation);
   }
 
-  virtual Representation RequiredInputRepresentation(int index) {
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     return Representation::None();
   }
 
   DECLARE_CONCRETE_INSTRUCTION(IsNumberAndBranch)
 };
 
 
-class HCheckHeapObject: public HUnaryOperation {
+class HCheckHeapObject V8_FINAL : public HUnaryOperation {
  public:
   DECLARE_INSTRUCTION_FACTORY_P1(HCheckHeapObject, HValue*);
 
-  virtual bool HasEscapingOperandAt(int index) { return false; }
-  virtual Representation RequiredInputRepresentation(int index) {
+  virtual bool HasEscapingOperandAt(int index) V8_OVERRIDE { return false; }
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     return Representation::Tagged();
   }
 
 #ifdef DEBUG
-  virtual void Verify();
+  virtual void Verify() V8_OVERRIDE;
 #endif
 
-  virtual HValue* Canonicalize() {
+  virtual HValue* Canonicalize() V8_OVERRIDE {
     return value()->type().IsHeapObject() ? NULL : this;
   }
 
   DECLARE_CONCRETE_INSTRUCTION(CheckHeapObject)
 
  protected:
-  virtual bool DataEquals(HValue* other) { return true; }
+  virtual bool DataEquals(HValue* other) V8_OVERRIDE { return true; }
 
  private:
   explicit HCheckHeapObject(HValue* value)
       : HUnaryOperation(value, HType::NonPrimitive()) {
     set_representation(Representation::Tagged());
     SetFlag(kUseGVN);
   }
 };
 
 
@@ skipping 11 matching lines @@
         limit_is_upper(false), limit_is_included(false) {}
 };
 
 
 class HBoundsCheck;
 class HPhi;
 class HConstant;
 class HBitwise;
 
 
-class InductionVariableData : public ZoneObject {
+class InductionVariableData V8_FINAL : public ZoneObject {
  public:
   class InductionVariableCheck : public ZoneObject {
    public:
     HBoundsCheck* check() { return check_; }
     InductionVariableCheck* next() { return next_; }
     bool HasUpperLimit() { return upper_limit_ >= 0; }
     int32_t upper_limit() {
       ASSERT(HasUpperLimit());
       return upper_limit_;
     }
@@ skipping 179 matching lines @@
   HBasicBlock* induction_exit_block_;
   HBasicBlock* induction_exit_target_;
   ChecksRelatedToLength* checks_;
   HValue* additional_upper_limit_;
   bool additional_upper_limit_is_included_;
   HValue* additional_lower_limit_;
   bool additional_lower_limit_is_included_;
 };
 
 
-class HPhi: public HValue {
+class HPhi V8_FINAL : public HValue {
  public:
   HPhi(int merged_index, Zone* zone)
       : inputs_(2, zone),
         merged_index_(merged_index),
         phi_id_(-1),
         induction_variable_data_(NULL) {
     for (int i = 0; i < Representation::kNumRepresentations; i++) {
       non_phi_uses_[i] = 0;
       indirect_uses_[i] = 0;
     }
-    ASSERT(merged_index >= 0);
+    ASSERT(merged_index >= 0 || merged_index == kInvalidMergedIndex);
     SetFlag(kFlexibleRepresentation);
     SetFlag(kAllowUndefinedAsNaN);
   }
 
-  virtual Representation RepresentationFromInputs();
+  virtual Representation RepresentationFromInputs() V8_OVERRIDE;
 
-  virtual Range* InferRange(Zone* zone);
-  virtual void InferRepresentation(HInferRepresentationPhase* h_infer);
-  virtual Representation RequiredInputRepresentation(int index) {
+  virtual Range* InferRange(Zone* zone) V8_OVERRIDE;
+  virtual void InferRepresentation(
+      HInferRepresentationPhase* h_infer) V8_OVERRIDE;
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     return representation();
   }
-  virtual Representation KnownOptimalRepresentation() {
+  virtual Representation KnownOptimalRepresentation() V8_OVERRIDE {
     return representation();
   }
-  virtual HType CalculateInferredType();
-  virtual int OperandCount() { return inputs_.length(); }
-  virtual HValue* OperandAt(int index) const { return inputs_[index]; }
+  virtual HType CalculateInferredType() V8_OVERRIDE;
+  virtual int OperandCount() V8_OVERRIDE { return inputs_.length(); }
+  virtual HValue* OperandAt(int index) const V8_OVERRIDE {
+    return inputs_[index];
+  }
   HValue* GetRedundantReplacement();
   void AddInput(HValue* value);
   bool HasRealUses();
 
   bool IsReceiver() const { return merged_index_ == 0; }
+  bool HasMergedIndex() const { return merged_index_ != kInvalidMergedIndex; }
 
   int merged_index() const { return merged_index_; }
 
   InductionVariableData* induction_variable_data() {
     return induction_variable_data_;
   }
   bool IsInductionVariable() {
     return induction_variable_data_ != NULL;
   }
   bool IsLimitedInductionVariable() {
     return IsInductionVariable() &&
         induction_variable_data_->limit() != NULL;
   }
   void DetectInductionVariable() {
     ASSERT(induction_variable_data_ == NULL);
     induction_variable_data_ = InductionVariableData::ExaminePhi(this);
   }
 
-  virtual void PrintTo(StringStream* stream);
+  virtual void PrintTo(StringStream* stream) V8_OVERRIDE;
 
 #ifdef DEBUG
-  virtual void Verify();
+  virtual void Verify() V8_OVERRIDE;
 #endif
 
   void InitRealUses(int id);
   void AddNonPhiUsesFrom(HPhi* other);
   void AddIndirectUsesTo(int* use_count);
 
   int tagged_non_phi_uses() const {
     return non_phi_uses_[Representation::kTagged];
   }
   int smi_non_phi_uses() const {
@@ skipping 16 matching lines @@
   }
   int double_indirect_uses() const {
     return indirect_uses_[Representation::kDouble];
   }
   int phi_id() { return phi_id_; }
 
   static HPhi* cast(HValue* value) {
     ASSERT(value->IsPhi());
     return reinterpret_cast<HPhi*>(value);
   }
-  virtual Opcode opcode() const { return HValue::kPhi; }
+  virtual Opcode opcode() const V8_OVERRIDE { return HValue::kPhi; }
 
   void SimplifyConstantInputs();
 
+  // Marker value representing an invalid merge index.
+  static const int kInvalidMergedIndex = -1;
+
  protected:
-  virtual void DeleteFromGraph();
-  virtual void InternalSetOperandAt(int index, HValue* value) {
+  virtual void DeleteFromGraph() V8_OVERRIDE;
+  virtual void InternalSetOperandAt(int index, HValue* value) V8_OVERRIDE {
     inputs_[index] = value;
   }
 
  private:
   ZoneList<HValue*> inputs_;
   int merged_index_;
 
   int non_phi_uses_[Representation::kNumRepresentations];
   int indirect_uses_[Representation::kNumRepresentations];
   int phi_id_;
   InductionVariableData* induction_variable_data_;
 
   // TODO(titzer): we can't eliminate the receiver for generating backtraces
-  virtual bool IsDeletable() const { return !IsReceiver(); }
+  virtual bool IsDeletable() const V8_OVERRIDE { return !IsReceiver(); }
 };
 
 
 // Common base class for HArgumentsObject and HCapturedObject.
-class HDematerializedObject: public HTemplateInstruction<0> {
+class HDematerializedObject : public HInstruction {
  public:
   HDematerializedObject(int count, Zone* zone) : values_(count, zone) {}
 
-  virtual int OperandCount() { return values_.length(); }
-  virtual HValue* OperandAt(int index) const { return values_[index]; }
+  virtual int OperandCount() V8_FINAL V8_OVERRIDE { return values_.length(); }
+  virtual HValue* OperandAt(int index) const V8_FINAL V8_OVERRIDE {
+    return values_[index];
+  }
 
-  virtual bool HasEscapingOperandAt(int index) { return false; }
-  virtual Representation RequiredInputRepresentation(int index) {
+  virtual bool HasEscapingOperandAt(int index) V8_FINAL V8_OVERRIDE {
+    return false;
+  }
+  virtual Representation RequiredInputRepresentation(
+      int index) V8_FINAL V8_OVERRIDE {
     return Representation::None();
   }
 
  protected:
-  virtual void InternalSetOperandAt(int index, HValue* value) {
+  virtual void InternalSetOperandAt(int index,
+                                    HValue* value) V8_FINAL V8_OVERRIDE {
     values_[index] = value;
   }
 
   // List of values tracked by this marker.
   ZoneList<HValue*> values_;
 
  private:
-  virtual bool IsDeletable() const { return true; }
+  virtual bool IsDeletable() const V8_FINAL V8_OVERRIDE { return true; }
 };
 
 
-class HArgumentsObject: public HDematerializedObject {
+class HArgumentsObject V8_FINAL : public HDematerializedObject {
  public:
   static HArgumentsObject* New(Zone* zone, HValue* context, int count) {
     return new(zone) HArgumentsObject(count, zone);
   }
 
   // The values contain a list of all elements in the arguments object
   // including the receiver object, which is skipped when materializing.
   const ZoneList<HValue*>* arguments_values() const { return &values_; }
   int arguments_count() const { return values_.length(); }
 
   void AddArgument(HValue* argument, Zone* zone) {
     values_.Add(NULL, zone);  // Resize list.
     SetOperandAt(values_.length() - 1, argument);
   }
 
   DECLARE_CONCRETE_INSTRUCTION(ArgumentsObject)
 
  private:
   HArgumentsObject(int count, Zone* zone)
       : HDematerializedObject(count, zone) {
     set_representation(Representation::Tagged());
     SetFlag(kIsArguments);
   }
 };
 
 
-class HCapturedObject: public HDematerializedObject {
+class HCapturedObject V8_FINAL : public HDematerializedObject {
  public:
   HCapturedObject(int length, Zone* zone)
       : HDematerializedObject(length, zone) {
     set_representation(Representation::Tagged());
     values_.AddBlock(NULL, length, zone);  // Resize list.
   }
 
   // The values contain a list of all in-object properties inside the
   // captured object and is index by field index. Properties in the
   // properties or elements backing store are not tracked here.
   const ZoneList<HValue*>* values() const { return &values_; }
   int length() const { return values_.length(); }
 
   DECLARE_CONCRETE_INSTRUCTION(CapturedObject)
 };
 
 
-class HConstant: public HTemplateInstruction<0> {
+class HConstant V8_FINAL : public HTemplateInstruction<0> {
  public:
   DECLARE_INSTRUCTION_FACTORY_P1(HConstant, int32_t);
   DECLARE_INSTRUCTION_FACTORY_P2(HConstant, int32_t, Representation);
   DECLARE_INSTRUCTION_FACTORY_P1(HConstant, double);
   DECLARE_INSTRUCTION_FACTORY_P1(HConstant, Handle<Object>);
   DECLARE_INSTRUCTION_FACTORY_P1(HConstant, ExternalReference);
 
   Handle<Object> handle() {
     if (handle_.is_null()) {
       Factory* factory = Isolate::Current()->factory();
       // Default arguments to is_not_in_new_space depend on this heap number
       // to be tenured so that it's guaranteed not be be located in new space.
       handle_ = factory->NewNumber(double_value_, TENURED);
     }
     AllowDeferredHandleDereference smi_check;
     ASSERT(has_int32_value_ || !handle_->IsSmi());
     return handle_;
   }
 
   bool InstanceOf(Handle<Map> map) {
-    return handle_->IsJSObject() &&
-        Handle<JSObject>::cast(handle_)->map() == *map;
+    Handle<Object> constant_object = handle();
+    return constant_object->IsJSObject() &&
+        Handle<JSObject>::cast(constant_object)->map() == *map;
   }
 
   bool IsSpecialDouble() const {
     return has_double_value_ &&
         (BitCast<int64_t>(double_value_) == BitCast<int64_t>(-0.0) ||
          FixedDoubleArray::is_the_hole_nan(double_value_) ||
          std::isnan(double_value_));
   }
 
   bool NotInNewSpace() const {
@@ skipping 23 matching lines @@
            unique_id_ == UniqueValueId(heap->true_value()) ||
            unique_id_ == UniqueValueId(heap->false_value()) ||
            unique_id_ == UniqueValueId(heap->the_hole_value()) ||
            unique_id_ == UniqueValueId(heap->empty_string());
   }
 
   bool IsCell() const {
     return is_cell_;
   }
 
-  virtual Representation RequiredInputRepresentation(int index) {
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     return Representation::None();
   }
 
-  virtual Representation KnownOptimalRepresentation() {
+  virtual Representation KnownOptimalRepresentation() V8_OVERRIDE {
     if (HasSmiValue() && kSmiValueSize == 31) return Representation::Smi();
     if (HasInteger32Value()) return Representation::Integer32();
     if (HasNumberValue()) return Representation::Double();
     if (HasExternalReferenceValue()) return Representation::External();
     return Representation::Tagged();
   }
 
-  virtual bool EmitAtUses();
-  virtual void PrintDataTo(StringStream* stream);
+  virtual bool EmitAtUses() V8_OVERRIDE;
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
   bool IsInteger() { return handle()->IsSmi(); }
   HConstant* CopyToRepresentation(Representation r, Zone* zone) const;
   Maybe<HConstant*> CopyToTruncatedInt32(Zone* zone);
   Maybe<HConstant*> CopyToTruncatedNumber(Zone* zone);
   bool HasInteger32Value() const { return has_int32_value_; }
   int32_t Integer32Value() const {
     ASSERT(HasInteger32Value());
     return int32_value_;
   }
   bool HasSmiValue() const { return has_smi_value_; }
@@ skipping 33 matching lines @@
     return HasStringValue() && is_internalized_string_;
   }
 
   bool HasExternalReferenceValue() const {
     return has_external_reference_value_;
   }
   ExternalReference ExternalReferenceValue() const {
     return external_reference_value_;
   }
 
+  bool HasBooleanValue() const { return type_.IsBoolean(); }
   bool BooleanValue() const { return boolean_value_; }
 
-  virtual intptr_t Hashcode() {
+  virtual intptr_t Hashcode() V8_OVERRIDE {
     if (has_int32_value_) {
       return static_cast<intptr_t>(int32_value_);
     } else if (has_double_value_) {
       return static_cast<intptr_t>(BitCast<int64_t>(double_value_));
     } else if (has_external_reference_value_) {
       return reinterpret_cast<intptr_t>(external_reference_value_.address());
     } else {
       ASSERT(!handle_.is_null());
       return unique_id_.Hashcode();
     }
   }
 
-  virtual void FinalizeUniqueValueId() {
+  virtual void FinalizeUniqueValueId() V8_OVERRIDE {
     if (!has_double_value_ && !has_external_reference_value_) {
       ASSERT(!handle_.is_null());
       unique_id_ = UniqueValueId(handle_);
     }
   }
 
   bool UniqueValueIdsMatch(UniqueValueId other) {
     return !has_double_value_ && !has_external_reference_value_ &&
         unique_id_ == other;
   }
 
 #ifdef DEBUG
-  virtual void Verify() { }
+  virtual void Verify() V8_OVERRIDE { }
 #endif
 
   DECLARE_CONCRETE_INSTRUCTION(Constant)
 
  protected:
-  virtual Range* InferRange(Zone* zone);
+  virtual Range* InferRange(Zone* zone) V8_OVERRIDE;
 
-  virtual bool DataEquals(HValue* other) {
+  virtual bool DataEquals(HValue* other) V8_OVERRIDE {
     HConstant* other_constant = HConstant::cast(other);
     if (has_int32_value_) {
       return other_constant->has_int32_value_ &&
           int32_value_ == other_constant->int32_value_;
     } else if (has_double_value_) {
       return other_constant->has_double_value_ &&
           BitCast<int64_t>(double_value_) ==
           BitCast<int64_t>(other_constant->double_value_);
     } else if (has_external_reference_value_) {
       return other_constant->has_external_reference_value_ &&
@@ skipping 22 matching lines @@
             Representation r,
             HType type,
             bool is_internalized_string,
             bool is_not_in_new_space,
             bool is_cell,
             bool boolean_value);
   explicit HConstant(ExternalReference reference);
 
   void Initialize(Representation r);
 
-  virtual bool IsDeletable() const { return true; }
+  virtual bool IsDeletable() const V8_OVERRIDE { return true; }
 
   // If this is a numerical constant, handle_ either points to to the
   // HeapObject the constant originated from or is null.  If the
   // constant is non-numeric, handle_ always points to a valid
   // constant HeapObject.
   Handle<Object> handle_;
   UniqueValueId unique_id_;
 
   // We store the HConstant in the most specific form safely possible.
   // The two flags, has_int32_value_ and has_double_value_ tell us if
   // int32_value_ and double_value_ hold valid, safe representations
   // of the constant.  has_int32_value_ implies has_double_value_ but
   // not the converse.
   bool has_smi_value_ : 1;
   bool has_int32_value_ : 1;
   bool has_double_value_ : 1;
   bool has_external_reference_value_ : 1;
   bool is_internalized_string_ : 1;  // TODO(yangguo): make this part of HType.
   bool is_not_in_new_space_ : 1;
   bool is_cell_ : 1;
   bool boolean_value_ : 1;
   int32_t int32_value_;
   double double_value_;
   ExternalReference external_reference_value_;
 };
 
 
-class HBinaryOperation: public HTemplateInstruction<3> {
+class HBinaryOperation : public HTemplateInstruction<3> {
  public:
   HBinaryOperation(HValue* context, HValue* left, HValue* right,
                    HType type = HType::Tagged())
       : HTemplateInstruction<3>(type),
         observed_output_representation_(Representation::None()) {
     ASSERT(left != NULL && right != NULL);
     SetOperandAt(0, context);
     SetOperandAt(1, left);
     SetOperandAt(2, right);
     observed_input_representation_[0] = Representation::None();
@@ skipping 29 matching lines @@
 
   void set_observed_input_representation(int index, Representation rep) {
     ASSERT(index >= 1 && index <= 2);
     observed_input_representation_[index - 1] = rep;
   }
 
   virtual void initialize_output_representation(Representation observed) {
     observed_output_representation_ = observed;
   }
 
-  virtual Representation observed_input_representation(int index) {
+  virtual Representation observed_input_representation(int index) V8_OVERRIDE {
     if (index == 0) return Representation::Tagged();
     return observed_input_representation_[index - 1];
   }
 
   virtual void UpdateRepresentation(Representation new_rep,
                                     HInferRepresentationPhase* h_infer,
-                                    const char* reason) {
+                                    const char* reason) V8_OVERRIDE {
     Representation rep = !FLAG_smi_binop && new_rep.IsSmi()
         ? Representation::Integer32() : new_rep;
     HValue::UpdateRepresentation(rep, h_infer, reason);
   }
 
-  virtual void InferRepresentation(HInferRepresentationPhase* h_infer);
-  virtual Representation RepresentationFromInputs();
+  virtual void InferRepresentation(
+      HInferRepresentationPhase* h_infer) V8_OVERRIDE;
+  virtual Representation RepresentationFromInputs() V8_OVERRIDE;
   Representation RepresentationFromOutput();
-  virtual void AssumeRepresentation(Representation r);
+  virtual void AssumeRepresentation(Representation r) V8_OVERRIDE;
 
   virtual bool IsCommutative() const { return false; }
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
-  virtual Representation RequiredInputRepresentation(int index) {
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     if (index == 0) return Representation::Tagged();
     return representation();
   }
 
   DECLARE_ABSTRACT_INSTRUCTION(BinaryOperation)
 
  private:
   bool IgnoreObservedOutputRepresentation(Representation current_rep);
 
   Representation observed_input_representation_[2];
   Representation observed_output_representation_;
 };
 
 
-class HWrapReceiver: public HTemplateInstruction<2> {
+class HWrapReceiver V8_FINAL : public HTemplateInstruction<2> {
  public:
   DECLARE_INSTRUCTION_FACTORY_P2(HWrapReceiver, HValue*, HValue*);
 
-  virtual Representation RequiredInputRepresentation(int index) {
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     return Representation::Tagged();
   }
 
   HValue* receiver() { return OperandAt(0); }
   HValue* function() { return OperandAt(1); }
 
-  virtual HValue* Canonicalize();
+  virtual HValue* Canonicalize() V8_OVERRIDE;
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
   DECLARE_CONCRETE_INSTRUCTION(WrapReceiver)
 
  private:
   HWrapReceiver(HValue* receiver, HValue* function) {
     set_representation(Representation::Tagged());
     SetOperandAt(0, receiver);
     SetOperandAt(1, function);
   }
 };
 
 
-class HApplyArguments: public HTemplateInstruction<4> {
+class HApplyArguments V8_FINAL : public HTemplateInstruction<4> {
  public:
   HApplyArguments(HValue* function,
                   HValue* receiver,
                   HValue* length,
                   HValue* elements) {
     set_representation(Representation::Tagged());
     SetOperandAt(0, function);
     SetOperandAt(1, receiver);
     SetOperandAt(2, length);
     SetOperandAt(3, elements);
     SetAllSideEffects();
   }
 
-  virtual Representation RequiredInputRepresentation(int index) {
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     // The length is untagged, all other inputs are tagged.
     return (index == 2)
         ? Representation::Integer32()
         : Representation::Tagged();
   }
 
   HValue* function() { return OperandAt(0); }
   HValue* receiver() { return OperandAt(1); }
   HValue* length() { return OperandAt(2); }
   HValue* elements() { return OperandAt(3); }
 
   DECLARE_CONCRETE_INSTRUCTION(ApplyArguments)
 };
 
 
-class HArgumentsElements: public HTemplateInstruction<0> {
+class HArgumentsElements V8_FINAL : public HTemplateInstruction<0> {
  public:
   DECLARE_INSTRUCTION_FACTORY_P1(HArgumentsElements, bool);
 
   DECLARE_CONCRETE_INSTRUCTION(ArgumentsElements)
 
-  virtual Representation RequiredInputRepresentation(int index) {
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     return Representation::None();
   }
 
   bool from_inlined() const { return from_inlined_; }
 
  protected:
-  virtual bool DataEquals(HValue* other) { return true; }
+  virtual bool DataEquals(HValue* other) V8_OVERRIDE { return true; }
 
  private:
   explicit HArgumentsElements(bool from_inlined) : from_inlined_(from_inlined) {
     // The value produced by this instruction is a pointer into the stack
     // that looks as if it was a smi because of alignment.
     set_representation(Representation::Tagged());
     SetFlag(kUseGVN);
   }
 
-  virtual bool IsDeletable() const { return true; }
+  virtual bool IsDeletable() const V8_OVERRIDE { return true; }
 
   bool from_inlined_;
 };
 
 
-class HArgumentsLength: public HUnaryOperation {
+class HArgumentsLength V8_FINAL : public HUnaryOperation {
  public:
   DECLARE_INSTRUCTION_FACTORY_P1(HArgumentsLength, HValue*);
 
-  virtual Representation RequiredInputRepresentation(int index) {
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     return Representation::Tagged();
   }
 
   DECLARE_CONCRETE_INSTRUCTION(ArgumentsLength)
 
  protected:
-  virtual bool DataEquals(HValue* other) { return true; }
+  virtual bool DataEquals(HValue* other) V8_OVERRIDE { return true; }
 
  private:
   explicit HArgumentsLength(HValue* value) : HUnaryOperation(value) {
     set_representation(Representation::Integer32());
     SetFlag(kUseGVN);
   }
 
-  virtual bool IsDeletable() const { return true; }
+  virtual bool IsDeletable() const V8_OVERRIDE { return true; }
 };
 
 
-class HAccessArgumentsAt: public HTemplateInstruction<3> {
+class HAccessArgumentsAt V8_FINAL : public HTemplateInstruction<3> {
  public:
   HAccessArgumentsAt(HValue* arguments, HValue* length, HValue* index) {
     set_representation(Representation::Tagged());
     SetFlag(kUseGVN);
     SetOperandAt(0, arguments);
     SetOperandAt(1, length);
     SetOperandAt(2, index);
   }
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
-  virtual Representation RequiredInputRepresentation(int index) {
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     // The arguments elements is considered tagged.
     return index == 0
         ? Representation::Tagged()
         : Representation::Integer32();
   }
 
   HValue* arguments() { return OperandAt(0); }
   HValue* length() { return OperandAt(1); }
   HValue* index() { return OperandAt(2); }
 
   DECLARE_CONCRETE_INSTRUCTION(AccessArgumentsAt)
 
-  virtual bool DataEquals(HValue* other) { return true; }
+  virtual bool DataEquals(HValue* other) V8_OVERRIDE { return true; }
 };
 
 
 class HBoundsCheckBaseIndexInformation;
 
 
-class HBoundsCheck: public HTemplateInstruction<2> {
+class HBoundsCheck V8_FINAL : public HTemplateInstruction<2> {
  public:
   DECLARE_INSTRUCTION_FACTORY_P2(HBoundsCheck, HValue*, HValue*);
 
   bool skip_check() const { return skip_check_; }
   void set_skip_check() { skip_check_ = true; }
 
   HValue* base() { return base_; }
   int offset() { return offset_; }
   int scale() { return scale_; }
 
   void ApplyIndexChange();
   bool DetectCompoundIndex() {
     ASSERT(base() == NULL);
 
     DecompositionResult decomposition;
     if (index()->TryDecompose(&decomposition)) {
       base_ = decomposition.base();
       offset_ = decomposition.offset();
       scale_ = decomposition.scale();
       return true;
     } else {
       base_ = index();
       offset_ = 0;
       scale_ = 0;
       return false;
     }
   }
 
-  virtual Representation RequiredInputRepresentation(int arg_index) {
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     return representation();
   }
 
-  virtual void PrintDataTo(StringStream* stream);
-  virtual void InferRepresentation(HInferRepresentationPhase* h_infer);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
+  virtual void InferRepresentation(
+      HInferRepresentationPhase* h_infer) V8_OVERRIDE;
 
   HValue* index() { return OperandAt(0); }
   HValue* length() { return OperandAt(1); }
   bool allow_equality() { return allow_equality_; }
   void set_allow_equality(bool v) { allow_equality_ = v; }
 
-  virtual int RedefinedOperandIndex() { return 0; }
-  virtual bool IsPurelyInformativeDefinition() { return skip_check(); }
+  virtual int RedefinedOperandIndex() V8_OVERRIDE { return 0; }
+  virtual bool IsPurelyInformativeDefinition() V8_OVERRIDE {
+    return skip_check();
+  }
 
   DECLARE_CONCRETE_INSTRUCTION(BoundsCheck)
 
  protected:
   friend class HBoundsCheckBaseIndexInformation;
 
-  virtual bool DataEquals(HValue* other) { return true; }
+  virtual bool DataEquals(HValue* other) V8_OVERRIDE { return true; }
   bool skip_check_;
   HValue* base_;
   int offset_;
   int scale_;
   bool allow_equality_;
 
  private:
   // Normally HBoundsCheck should be created using the
   // HGraphBuilder::AddBoundsCheck() helper.
   // However when building stubs, where we know that the arguments are Int32,
   // it makes sense to invoke this constructor directly.
   HBoundsCheck(HValue* index, HValue* length)
     : skip_check_(false),
       base_(NULL), offset_(0), scale_(0),
       allow_equality_(false) {
     SetOperandAt(0, index);
     SetOperandAt(1, length);
     SetFlag(kFlexibleRepresentation);
     SetFlag(kUseGVN);
   }
 
-  virtual bool IsDeletable() const {
+  virtual bool IsDeletable() const V8_OVERRIDE {
     return skip_check() && !FLAG_debug_code;
   }
 };
 
 
-class HBoundsCheckBaseIndexInformation: public HTemplateInstruction<2> {
+class HBoundsCheckBaseIndexInformation V8_FINAL
+    : public HTemplateInstruction<2> {
  public:
   explicit HBoundsCheckBaseIndexInformation(HBoundsCheck* check) {
     DecompositionResult decomposition;
     if (check->index()->TryDecompose(&decomposition)) {
       SetOperandAt(0, decomposition.base());
       SetOperandAt(1, check);
     } else {
       UNREACHABLE();
     }
   }
 
   HValue* base_index() { return OperandAt(0); }
   HBoundsCheck* bounds_check() { return HBoundsCheck::cast(OperandAt(1)); }
 
   DECLARE_CONCRETE_INSTRUCTION(BoundsCheckBaseIndexInformation)
 
-  virtual Representation RequiredInputRepresentation(int arg_index) {
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     return representation();
   }
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
-  virtual int RedefinedOperandIndex() { return 0; }
-  virtual bool IsPurelyInformativeDefinition() { return true; }
+  virtual int RedefinedOperandIndex() V8_OVERRIDE { return 0; }
+  virtual bool IsPurelyInformativeDefinition() V8_OVERRIDE { return true; }
 };
 
 
-class HBitwiseBinaryOperation: public HBinaryOperation {
+class HBitwiseBinaryOperation : public HBinaryOperation {
  public:
   HBitwiseBinaryOperation(HValue* context, HValue* left, HValue* right,
                           HType type = HType::Tagged())
       : HBinaryOperation(context, left, right, type) {
     SetFlag(kFlexibleRepresentation);
     SetFlag(kTruncatingToInt32);
     SetFlag(kAllowUndefinedAsNaN);
     SetAllSideEffects();
   }
 
-  virtual void RepresentationChanged(Representation to) {
+  virtual void RepresentationChanged(Representation to) V8_OVERRIDE {
     if (!to.IsTagged()) {
       ASSERT(to.IsSmiOrInteger32());
       ClearAllSideEffects();
       SetFlag(kUseGVN);
     } else {
       SetAllSideEffects();
       ClearFlag(kUseGVN);
     }
   }
 
   virtual void UpdateRepresentation(Representation new_rep,
                                     HInferRepresentationPhase* h_infer,
-                                    const char* reason) {
+                                    const char* reason) V8_OVERRIDE {
     // We only generate either int32 or generic tagged bitwise operations.
     if (new_rep.IsDouble()) new_rep = Representation::Integer32();
     HBinaryOperation::UpdateRepresentation(new_rep, h_infer, reason);
   }
 
-  virtual Representation observed_input_representation(int index) {
+  virtual Representation observed_input_representation(int index) V8_OVERRIDE {
     Representation r = HBinaryOperation::observed_input_representation(index);
     if (r.IsDouble()) return Representation::Integer32();
     return r;
   }
 
   virtual void initialize_output_representation(Representation observed) {
     if (observed.IsDouble()) observed = Representation::Integer32();
     HBinaryOperation::initialize_output_representation(observed);
   }
 
   DECLARE_ABSTRACT_INSTRUCTION(BitwiseBinaryOperation)
 
  private:
-  virtual bool IsDeletable() const { return true; }
+  virtual bool IsDeletable() const V8_OVERRIDE { return true; }
 };
 
 
-class HMathFloorOfDiv: public HBinaryOperation {
+class HMathFloorOfDiv V8_FINAL : public HBinaryOperation {
  public:
   static HMathFloorOfDiv* New(Zone* zone,
                               HValue* context,
                               HValue* left,
                               HValue* right) {
     return new(zone) HMathFloorOfDiv(context, left, right);
   }
 
-  virtual HValue* EnsureAndPropagateNotMinusZero(BitVector* visited);
-
-  virtual Representation RequiredInputRepresentation(int index) {
-    return Representation::Integer32();
-  }
+  virtual HValue* EnsureAndPropagateNotMinusZero(
+      BitVector* visited) V8_OVERRIDE;
 
   DECLARE_CONCRETE_INSTRUCTION(MathFloorOfDiv)
 
  protected:
-  virtual bool DataEquals(HValue* other) { return true; }
+  virtual bool DataEquals(HValue* other) V8_OVERRIDE { return true; }
 
  private:
   HMathFloorOfDiv(HValue* context, HValue* left, HValue* right)
       : HBinaryOperation(context, left, right) {
     set_representation(Representation::Integer32());
     SetFlag(kUseGVN);
     SetFlag(kCanOverflow);
     if (!right->IsConstant()) {
       SetFlag(kCanBeDivByZero);
     }
     SetFlag(kAllowUndefinedAsNaN);
   }
 
-  virtual bool IsDeletable() const { return true; }
+  virtual bool IsDeletable() const V8_OVERRIDE { return true; }
 };
 
 
-class HArithmeticBinaryOperation: public HBinaryOperation {
+class HArithmeticBinaryOperation : public HBinaryOperation {
  public:
   HArithmeticBinaryOperation(HValue* context, HValue* left, HValue* right)
       : HBinaryOperation(context, left, right, HType::TaggedNumber()) {
     SetAllSideEffects();
     SetFlag(kFlexibleRepresentation);
     SetFlag(kAllowUndefinedAsNaN);
   }
 
-  virtual void RepresentationChanged(Representation to) {
+  virtual void RepresentationChanged(Representation to) V8_OVERRIDE {
     if (to.IsTagged()) {
       SetAllSideEffects();
       ClearFlag(kUseGVN);
     } else {
       ClearAllSideEffects();
       SetFlag(kUseGVN);
     }
   }
 
   DECLARE_ABSTRACT_INSTRUCTION(ArithmeticBinaryOperation)
 
  private:
-  virtual bool IsDeletable() const { return true; }
+  virtual bool IsDeletable() const V8_OVERRIDE { return true; }
 };
 
 
-class HCompareGeneric: public HBinaryOperation {
+class HCompareGeneric V8_FINAL : public HBinaryOperation {
  public:
   HCompareGeneric(HValue* context,
                   HValue* left,
                   HValue* right,
                   Token::Value token)
       : HBinaryOperation(context, left, right, HType::Boolean()),
         token_(token) {
     ASSERT(Token::IsCompareOp(token));
     set_representation(Representation::Tagged());
     SetAllSideEffects();
   }
 
-  virtual Representation RequiredInputRepresentation(int index) {
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     return index == 0
         ? Representation::Tagged()
         : representation();
   }
 
   Token::Value token() const { return token_; }
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
   DECLARE_CONCRETE_INSTRUCTION(CompareGeneric)
 
  private:
   Token::Value token_;
 };
 
 
-class HCompareNumericAndBranch: public HTemplateControlInstruction<2, 2> {
+class HCompareNumericAndBranch : public HTemplateControlInstruction<2, 2> {
  public:
   HCompareNumericAndBranch(HValue* left, HValue* right, Token::Value token)
       : token_(token) {
     SetFlag(kFlexibleRepresentation);
     ASSERT(Token::IsCompareOp(token));
     SetOperandAt(0, left);
     SetOperandAt(1, right);
   }
 
   HValue* left() { return OperandAt(0); }
   HValue* right() { return OperandAt(1); }
   Token::Value token() const { return token_; }
 
   void set_observed_input_representation(Representation left,
                                          Representation right) {
       observed_input_representation_[0] = left;
       observed_input_representation_[1] = right;
   }
 
-  virtual void InferRepresentation(HInferRepresentationPhase* h_infer);
+  virtual void InferRepresentation(
+      HInferRepresentationPhase* h_infer) V8_OVERRIDE;
 
-  virtual Representation RequiredInputRepresentation(int index) {
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     return representation();
   }
-  virtual Representation observed_input_representation(int index) {
+  virtual Representation observed_input_representation(int index) V8_OVERRIDE {
     return observed_input_representation_[index];
   }
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
   DECLARE_CONCRETE_INSTRUCTION(CompareNumericAndBranch)
 
  private:
   Representation observed_input_representation_[2];
   Token::Value token_;
 };
 
 
-class HCompareObjectEqAndBranch: public HTemplateControlInstruction<2, 2> {
+class HCompareHoleAndBranch V8_FINAL
+    : public HTemplateControlInstruction<2, 1> {
  public:
   // TODO(danno): make this private when the IfBuilder properly constructs
   // control flow instructions.
+  explicit HCompareHoleAndBranch(HValue* object) {
+    SetFlag(kFlexibleRepresentation);
+    SetFlag(kAllowUndefinedAsNaN);
+    SetOperandAt(0, object);
+  }
+
+  DECLARE_INSTRUCTION_FACTORY_P1(HCompareHoleAndBranch, HValue*);
+
+  HValue* object() { return OperandAt(0); }
+
+  virtual void InferRepresentation(
+      HInferRepresentationPhase* h_infer) V8_OVERRIDE;
+
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
+    return representation();
+  }
+
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
+
+  DECLARE_CONCRETE_INSTRUCTION(CompareHoleAndBranch)
+};
+
+
+class HCompareObjectEqAndBranch : public HTemplateControlInstruction<2, 2> {
+ public:
+  // TODO(danno): make this private when the IfBuilder properly constructs
+  // control flow instructions.
   HCompareObjectEqAndBranch(HValue* left,
                             HValue* right) {
     SetOperandAt(0, left);
     SetOperandAt(1, right);
   }
 
   DECLARE_INSTRUCTION_FACTORY_P2(HCompareObjectEqAndBranch, HValue*, HValue*);
 
   HValue* left() { return OperandAt(0); }
   HValue* right() { return OperandAt(1); }
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
-  virtual Representation RequiredInputRepresentation(int index) {
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     return Representation::Tagged();
   }
 
-  virtual Representation observed_input_representation(int index) {
+  virtual Representation observed_input_representation(int index) V8_OVERRIDE {
     return Representation::Tagged();
   }
 
   DECLARE_CONCRETE_INSTRUCTION(CompareObjectEqAndBranch)
 };
 
 
-class HIsObjectAndBranch: public HUnaryControlInstruction {
+class HIsObjectAndBranch V8_FINAL : public HUnaryControlInstruction {
  public:
   explicit HIsObjectAndBranch(HValue* value)
     : HUnaryControlInstruction(value, NULL, NULL) { }
 
-  virtual Representation RequiredInputRepresentation(int index) {
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     return Representation::Tagged();
   }
 
   DECLARE_CONCRETE_INSTRUCTION(IsObjectAndBranch)
 };
 
-class HIsStringAndBranch: public HUnaryControlInstruction {
+class HIsStringAndBranch V8_FINAL : public HUnaryControlInstruction {
  public:
   explicit HIsStringAndBranch(HValue* value)
     : HUnaryControlInstruction(value, NULL, NULL) { }
 
-  virtual Representation RequiredInputRepresentation(int index) {
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     return Representation::Tagged();
   }
 
   DECLARE_CONCRETE_INSTRUCTION(IsStringAndBranch)
 };
 
 
-class HIsSmiAndBranch: public HUnaryControlInstruction {
+class HIsSmiAndBranch V8_FINAL : public HUnaryControlInstruction {
  public:
   explicit HIsSmiAndBranch(HValue* value)
       : HUnaryControlInstruction(value, NULL, NULL) { }
 
   DECLARE_CONCRETE_INSTRUCTION(IsSmiAndBranch)
 
-  virtual Representation RequiredInputRepresentation(int index) {
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     return Representation::Tagged();
   }
 
  protected:
-  virtual bool DataEquals(HValue* other) { return true; }
+  virtual bool DataEquals(HValue* other) V8_OVERRIDE { return true; }
 };
 
 
-class HIsUndetectableAndBranch: public HUnaryControlInstruction {
+class HIsUndetectableAndBranch V8_FINAL : public HUnaryControlInstruction {
  public:
   explicit HIsUndetectableAndBranch(HValue* value)
       : HUnaryControlInstruction(value, NULL, NULL) { }
 
-  virtual Representation RequiredInputRepresentation(int index) {
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     return Representation::Tagged();
   }
 
   DECLARE_CONCRETE_INSTRUCTION(IsUndetectableAndBranch)
 };
 
 
-class HStringCompareAndBranch: public HTemplateControlInstruction<2, 3> {
+class HStringCompareAndBranch : public HTemplateControlInstruction<2, 3> {
  public:
   HStringCompareAndBranch(HValue* context,
                            HValue* left,
                            HValue* right,
                            Token::Value token)
       : token_(token) {
     ASSERT(Token::IsCompareOp(token));
     SetOperandAt(0, context);
     SetOperandAt(1, left);
     SetOperandAt(2, right);
     set_representation(Representation::Tagged());
+    SetGVNFlag(kChangesNewSpacePromotion);
   }
 
   HValue* context() { return OperandAt(0); }
   HValue* left() { return OperandAt(1); }
   HValue* right() { return OperandAt(2); }
   Token::Value token() const { return token_; }
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
-  virtual Representation RequiredInputRepresentation(int index) {
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     return Representation::Tagged();
   }
 
   Representation GetInputRepresentation() const {
     return Representation::Tagged();
   }
 
   DECLARE_CONCRETE_INSTRUCTION(StringCompareAndBranch)
 
  private:
   Token::Value token_;
 };
 
 
-class HIsConstructCallAndBranch: public HTemplateControlInstruction<2, 0> {
+class HIsConstructCallAndBranch : public HTemplateControlInstruction<2, 0> {
  public:
-  virtual Representation RequiredInputRepresentation(int index) {
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     return Representation::None();
   }
 
   DECLARE_CONCRETE_INSTRUCTION(IsConstructCallAndBranch)
 };
 
 
-class HHasInstanceTypeAndBranch: public HUnaryControlInstruction {
+class HHasInstanceTypeAndBranch V8_FINAL : public HUnaryControlInstruction {
  public:
   HHasInstanceTypeAndBranch(HValue* value, InstanceType type)
       : HUnaryControlInstruction(value, NULL, NULL), from_(type), to_(type) { }
   HHasInstanceTypeAndBranch(HValue* value, InstanceType from, InstanceType to)
       : HUnaryControlInstruction(value, NULL, NULL), from_(from), to_(to) {
     ASSERT(to == LAST_TYPE);  // Others not implemented yet in backend.
   }
 
   InstanceType from() { return from_; }
   InstanceType to() { return to_; }
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
-  virtual Representation RequiredInputRepresentation(int index) {
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     return Representation::Tagged();
   }
 
   DECLARE_CONCRETE_INSTRUCTION(HasInstanceTypeAndBranch)
 
  private:
   InstanceType from_;
   InstanceType to_;  // Inclusive range, not all combinations work.
 };
 
 
-class HHasCachedArrayIndexAndBranch: public HUnaryControlInstruction {
+class HHasCachedArrayIndexAndBranch V8_FINAL : public HUnaryControlInstruction {
  public:
   explicit HHasCachedArrayIndexAndBranch(HValue* value)
       : HUnaryControlInstruction(value, NULL, NULL) { }
 
-  virtual Representation RequiredInputRepresentation(int index) {
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     return Representation::Tagged();
   }
 
   DECLARE_CONCRETE_INSTRUCTION(HasCachedArrayIndexAndBranch)
 };
 
 
-class HGetCachedArrayIndex: public HUnaryOperation {
+class HGetCachedArrayIndex V8_FINAL : public HUnaryOperation {
  public:
   explicit HGetCachedArrayIndex(HValue* value) : HUnaryOperation(value) {
     set_representation(Representation::Tagged());
     SetFlag(kUseGVN);
   }
 
-  virtual Representation RequiredInputRepresentation(int index) {
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     return Representation::Tagged();
   }
 
   DECLARE_CONCRETE_INSTRUCTION(GetCachedArrayIndex)
 
  protected:
-  virtual bool DataEquals(HValue* other) { return true; }
+  virtual bool DataEquals(HValue* other) V8_OVERRIDE { return true; }
 
  private:
-  virtual bool IsDeletable() const { return true; }
+  virtual bool IsDeletable() const V8_OVERRIDE { return true; }
 };
 
 
-class HClassOfTestAndBranch: public HUnaryControlInstruction {
+class HClassOfTestAndBranch V8_FINAL : public HUnaryControlInstruction {
  public:
   HClassOfTestAndBranch(HValue* value, Handle<String> class_name)
       : HUnaryControlInstruction(value, NULL, NULL),
         class_name_(class_name) { }
 
   DECLARE_CONCRETE_INSTRUCTION(ClassOfTestAndBranch)
 
-  virtual Representation RequiredInputRepresentation(int index) {
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     return Representation::Tagged();
   }
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
   Handle<String> class_name() const { return class_name_; }
 
  private:
   Handle<String> class_name_;
 };
 
 
-class HTypeofIsAndBranch: public HUnaryControlInstruction {
+class HTypeofIsAndBranch V8_FINAL : public HUnaryControlInstruction {
  public:
   HTypeofIsAndBranch(HValue* value, Handle<String> type_literal)
       : HUnaryControlInstruction(value, NULL, NULL),
         type_literal_(type_literal) { }
 
   Handle<String> type_literal() { return type_literal_; }
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
   DECLARE_CONCRETE_INSTRUCTION(TypeofIsAndBranch)
 
-  virtual Representation RequiredInputRepresentation(int index) {
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     return Representation::Tagged();
   }
 
  private:
   Handle<String> type_literal_;
 };
 
 
-class HInstanceOf: public HBinaryOperation {
+class HInstanceOf V8_FINAL : public HBinaryOperation {
  public:
   HInstanceOf(HValue* context, HValue* left, HValue* right)
       : HBinaryOperation(context, left, right, HType::Boolean()) {
     set_representation(Representation::Tagged());
     SetAllSideEffects();
   }
 
-  virtual Representation RequiredInputRepresentation(int index) {
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     return Representation::Tagged();
   }
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
   DECLARE_CONCRETE_INSTRUCTION(InstanceOf)
 };
 
 
-class HInstanceOfKnownGlobal: public HTemplateInstruction<2> {
+class HInstanceOfKnownGlobal V8_FINAL : public HTemplateInstruction<2> {
  public:
   HInstanceOfKnownGlobal(HValue* context,
                          HValue* left,
                          Handle<JSFunction> right)
       : HTemplateInstruction<2>(HType::Boolean()), function_(right) {
     SetOperandAt(0, context);
     SetOperandAt(1, left);
     set_representation(Representation::Tagged());
     SetAllSideEffects();
   }
 
   HValue* context() { return OperandAt(0); }
   HValue* left() { return OperandAt(1); }
   Handle<JSFunction> function() { return function_; }
 
-  virtual Representation RequiredInputRepresentation(int index) {
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     return Representation::Tagged();
   }
 
   DECLARE_CONCRETE_INSTRUCTION(InstanceOfKnownGlobal)
 
  private:
   Handle<JSFunction> function_;
 };
 
 
 // TODO(mstarzinger): This instruction should be modeled as a load of the map
 // field followed by a load of the instance size field once HLoadNamedField is
 // flexible enough to accommodate byte-field loads.
-class HInstanceSize: public HTemplateInstruction<1> {
+class HInstanceSize V8_FINAL : public HTemplateInstruction<1> {
  public:
   explicit HInstanceSize(HValue* object) {
     SetOperandAt(0, object);
     set_representation(Representation::Integer32());
   }
 
   HValue* object() { return OperandAt(0); }
 
-  virtual Representation RequiredInputRepresentation(int index) {
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     return Representation::Tagged();
   }
 
   DECLARE_CONCRETE_INSTRUCTION(InstanceSize)
 };
 
 
-class HPower: public HTemplateInstruction<2> {
+class HPower V8_FINAL : public HTemplateInstruction<2> {
  public:
   static HInstruction* New(Zone* zone,
                            HValue* context,
                            HValue* left,
                            HValue* right);
 
   HValue* left() { return OperandAt(0); }
   HValue* right() const { return OperandAt(1); }
 
-  virtual Representation RequiredInputRepresentation(int index) {
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     return index == 0
       ? Representation::Double()
       : Representation::None();
   }
-  virtual Representation observed_input_representation(int index) {
+  virtual Representation observed_input_representation(int index) V8_OVERRIDE {
     return RequiredInputRepresentation(index);
   }
 
   DECLARE_CONCRETE_INSTRUCTION(Power)
 
  protected:
-  virtual bool DataEquals(HValue* other) { return true; }
+  virtual bool DataEquals(HValue* other) V8_OVERRIDE { return true; }
 
  private:
   HPower(HValue* left, HValue* right) {
     SetOperandAt(0, left);
     SetOperandAt(1, right);
     set_representation(Representation::Double());
     SetFlag(kUseGVN);
     SetGVNFlag(kChangesNewSpacePromotion);
   }
 
-  virtual bool IsDeletable() const {
+  virtual bool IsDeletable() const V8_OVERRIDE {
     return !right()->representation().IsTagged();
   }
 };
 
 
-class HRandom: public HTemplateInstruction<1> {
+class HRandom V8_FINAL : public HTemplateInstruction<1> {
  public:
   explicit HRandom(HValue* global_object) {
     SetOperandAt(0, global_object);
     set_representation(Representation::Double());
   }
 
   HValue* global_object() { return OperandAt(0); }
 
-  virtual Representation RequiredInputRepresentation(int index) {
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     return Representation::Tagged();
   }
 
   DECLARE_CONCRETE_INSTRUCTION(Random)
 
  private:
-  virtual bool IsDeletable() const { return true; }
+  virtual bool IsDeletable() const V8_OVERRIDE { return true; }
 };
 
 
-class HAdd: public HArithmeticBinaryOperation {
+class HAdd V8_FINAL : public HArithmeticBinaryOperation {
  public:
   static HInstruction* New(Zone* zone,
                            HValue* context,
                            HValue* left,
                            HValue* right);
 
   // Add is only commutative if two integer values are added and not if two
   // tagged values are added (because it might be a String concatenation).
-  virtual bool IsCommutative() const {
+  virtual bool IsCommutative() const V8_OVERRIDE {
     return !representation().IsTagged();
   }
 
-  virtual HValue* EnsureAndPropagateNotMinusZero(BitVector* visited);
+  virtual HValue* EnsureAndPropagateNotMinusZero(
+      BitVector* visited) V8_OVERRIDE;
 
-  virtual HValue* Canonicalize();
+  virtual HValue* Canonicalize() V8_OVERRIDE;
 
-  virtual bool TryDecompose(DecompositionResult* decomposition) {
+  virtual bool TryDecompose(DecompositionResult* decomposition) V8_OVERRIDE {
     if (left()->IsInteger32Constant()) {
       decomposition->Apply(right(), left()->GetInteger32Constant());
       return true;
     } else if (right()->IsInteger32Constant()) {
       decomposition->Apply(left(), right()->GetInteger32Constant());
       return true;
     } else {
       return false;
     }
   }
 
+  virtual void RepresentationChanged(Representation to) V8_OVERRIDE {
+    if (to.IsTagged()) ClearFlag(kAllowUndefinedAsNaN);
+    HArithmeticBinaryOperation::RepresentationChanged(to);
+  }
+
   DECLARE_CONCRETE_INSTRUCTION(Add)
 
  protected:
-  virtual bool DataEquals(HValue* other) { return true; }
+  virtual bool DataEquals(HValue* other) V8_OVERRIDE { return true; }
 
-  virtual Range* InferRange(Zone* zone);
+  virtual Range* InferRange(Zone* zone) V8_OVERRIDE;
 
  private:
   HAdd(HValue* context, HValue* left, HValue* right)
       : HArithmeticBinaryOperation(context, left, right) {
     SetFlag(kCanOverflow);
   }
 };
 
 
-class HSub: public HArithmeticBinaryOperation {
+class HSub V8_FINAL : public HArithmeticBinaryOperation {
  public:
   static HInstruction* New(Zone* zone,
                            HValue* context,
                            HValue* left,
                            HValue* right);
 
-  virtual HValue* EnsureAndPropagateNotMinusZero(BitVector* visited);
+  virtual HValue* EnsureAndPropagateNotMinusZero(
+      BitVector* visited) V8_OVERRIDE;
 
-  virtual HValue* Canonicalize();
+  virtual HValue* Canonicalize() V8_OVERRIDE;
 
-  virtual bool TryDecompose(DecompositionResult* decomposition) {
+  virtual bool TryDecompose(DecompositionResult* decomposition) V8_OVERRIDE {
     if (right()->IsInteger32Constant()) {
       decomposition->Apply(left(), -right()->GetInteger32Constant());
       return true;
     } else {
       return false;
     }
   }
 
   DECLARE_CONCRETE_INSTRUCTION(Sub)
 
  protected:
-  virtual bool DataEquals(HValue* other) { return true; }
+  virtual bool DataEquals(HValue* other) V8_OVERRIDE { return true; }
 
-  virtual Range* InferRange(Zone* zone);
+  virtual Range* InferRange(Zone* zone) V8_OVERRIDE;
 
  private:
   HSub(HValue* context, HValue* left, HValue* right)
       : HArithmeticBinaryOperation(context, left, right) {
     SetFlag(kCanOverflow);
   }
 };
 
 
-class HMul: public HArithmeticBinaryOperation {
+class HMul V8_FINAL : public HArithmeticBinaryOperation {
  public:
   static HInstruction* New(Zone* zone,
                            HValue* context,
                            HValue* left,
                            HValue* right);
 
   static HInstruction* NewImul(Zone* zone,
                                HValue* context,
                                HValue* left,
                                HValue* right) {
     HMul* mul = new(zone) HMul(context, left, right);
     // TODO(mstarzinger): Prevent bailout on minus zero for imul.
     mul->AssumeRepresentation(Representation::Integer32());
     mul->ClearFlag(HValue::kCanOverflow);
     return mul;
   }
 
-  virtual HValue* EnsureAndPropagateNotMinusZero(BitVector* visited);
+  virtual HValue* EnsureAndPropagateNotMinusZero(
+      BitVector* visited) V8_OVERRIDE;
 
-  virtual HValue* Canonicalize();
+  virtual HValue* Canonicalize() V8_OVERRIDE;
 
   // Only commutative if it is certain that not two objects are multiplicated.
-  virtual bool IsCommutative() const {
+  virtual bool IsCommutative() const V8_OVERRIDE {
     return !representation().IsTagged();
   }
 
   virtual void UpdateRepresentation(Representation new_rep,
                                     HInferRepresentationPhase* h_infer,
-                                    const char* reason) {
+                                    const char* reason) V8_OVERRIDE {
     if (new_rep.IsSmi()) new_rep = Representation::Integer32();
     HArithmeticBinaryOperation::UpdateRepresentation(new_rep, h_infer, reason);
   }
 
   DECLARE_CONCRETE_INSTRUCTION(Mul)
 
  protected:
-  virtual bool DataEquals(HValue* other) { return true; }
+  virtual bool DataEquals(HValue* other) V8_OVERRIDE { return true; }
 
-  virtual Range* InferRange(Zone* zone);
+  virtual Range* InferRange(Zone* zone) V8_OVERRIDE;
 
  private:
   HMul(HValue* context, HValue* left, HValue* right)
       : HArithmeticBinaryOperation(context, left, right) {
     SetFlag(kCanOverflow);
   }
 };
 
 
-class HMod: public HArithmeticBinaryOperation {
+class HMod V8_FINAL : public HArithmeticBinaryOperation {
  public:
   static HInstruction* New(Zone* zone,
                            HValue* context,
                            HValue* left,
                            HValue* right,
                            Maybe<int> fixed_right_arg);
 
   Maybe<int> fixed_right_arg() const { return fixed_right_arg_; }
 
   bool HasPowerOf2Divisor() {
     if (right()->IsConstant() &&
         HConstant::cast(right())->HasInteger32Value()) {
       int32_t value = HConstant::cast(right())->Integer32Value();
       return value != 0 && (IsPowerOf2(value) || IsPowerOf2(-value));
     }
 
     return false;
   }
 
-  virtual HValue* EnsureAndPropagateNotMinusZero(BitVector* visited);
+  virtual HValue* EnsureAndPropagateNotMinusZero(
+      BitVector* visited) V8_OVERRIDE;
 
-  virtual HValue* Canonicalize();
+  virtual HValue* Canonicalize() V8_OVERRIDE;
 
   virtual void UpdateRepresentation(Representation new_rep,
                                     HInferRepresentationPhase* h_infer,
-                                    const char* reason) {
+                                    const char* reason) V8_OVERRIDE {
     if (new_rep.IsSmi()) new_rep = Representation::Integer32();
     HArithmeticBinaryOperation::UpdateRepresentation(new_rep, h_infer, reason);
   }
 
   DECLARE_CONCRETE_INSTRUCTION(Mod)
 
  protected:
-  virtual bool DataEquals(HValue* other) { return true; }
+  virtual bool DataEquals(HValue* other) V8_OVERRIDE { return true; }
 
-  virtual Range* InferRange(Zone* zone);
+  virtual Range* InferRange(Zone* zone) V8_OVERRIDE;
 
  private:
   HMod(HValue* context,
        HValue* left,
        HValue* right,
        Maybe<int> fixed_right_arg)
       : HArithmeticBinaryOperation(context, left, right),
         fixed_right_arg_(fixed_right_arg) {
     SetFlag(kCanBeDivByZero);
     SetFlag(kCanOverflow);
   }
 
   const Maybe<int> fixed_right_arg_;
 };
 
 
-class HDiv: public HArithmeticBinaryOperation {
+class HDiv V8_FINAL : public HArithmeticBinaryOperation {
  public:
   static HInstruction* New(Zone* zone,
                            HValue* context,
                            HValue* left,
                            HValue* right);
 
   bool HasPowerOf2Divisor() {
     if (right()->IsInteger32Constant()) {
       int32_t value = right()->GetInteger32Constant();
       return value != 0 && (IsPowerOf2(value) || IsPowerOf2(-value));
     }
 
     return false;
   }
 
-  virtual HValue* EnsureAndPropagateNotMinusZero(BitVector* visited);
+  virtual HValue* EnsureAndPropagateNotMinusZero(
+      BitVector* visited) V8_OVERRIDE;
 
-  virtual HValue* Canonicalize();
+  virtual HValue* Canonicalize() V8_OVERRIDE;
 
   virtual void UpdateRepresentation(Representation new_rep,
                                     HInferRepresentationPhase* h_infer,
-                                    const char* reason) {
+                                    const char* reason) V8_OVERRIDE {
     if (new_rep.IsSmi()) new_rep = Representation::Integer32();
     HArithmeticBinaryOperation::UpdateRepresentation(new_rep, h_infer, reason);
   }
 
   DECLARE_CONCRETE_INSTRUCTION(Div)
 
  protected:
-  virtual bool DataEquals(HValue* other) { return true; }
+  virtual bool DataEquals(HValue* other) V8_OVERRIDE { return true; }
 
-  virtual Range* InferRange(Zone* zone);
+  virtual Range* InferRange(Zone* zone) V8_OVERRIDE;
 
  private:
   HDiv(HValue* context, HValue* left, HValue* right)
       : HArithmeticBinaryOperation(context, left, right) {
     SetFlag(kCanBeDivByZero);
     SetFlag(kCanOverflow);
   }
 };
 
 
-class HMathMinMax: public HArithmeticBinaryOperation {
+class HMathMinMax V8_FINAL : public HArithmeticBinaryOperation {
  public:
   enum Operation { kMathMin, kMathMax };
 
   static HInstruction* New(Zone* zone,
                            HValue* context,
                            HValue* left,
                            HValue* right,
                            Operation op);
 
-  virtual Representation RequiredInputRepresentation(int index) {
-    return index == 0 ? Representation::Tagged()
-                      : representation();
-  }
-
-  virtual Representation observed_input_representation(int index) {
+  virtual Representation observed_input_representation(int index) V8_OVERRIDE {
     return RequiredInputRepresentation(index);
   }
 
-  virtual void InferRepresentation(HInferRepresentationPhase* h_infer);
+  virtual void InferRepresentation(
+      HInferRepresentationPhase* h_infer) V8_OVERRIDE;
 
-  virtual Representation RepresentationFromInputs() {
+  virtual Representation RepresentationFromInputs() V8_OVERRIDE {
     Representation left_rep = left()->representation();
     Representation right_rep = right()->representation();
     Representation result = Representation::Smi();
     result = result.generalize(left_rep);
     result = result.generalize(right_rep);
     if (result.IsTagged()) return Representation::Double();
     return result;
   }
 
-  virtual bool IsCommutative() const { return true; }
+  virtual bool IsCommutative() const V8_OVERRIDE { return true; }
 
   Operation operation() { return operation_; }
 
   DECLARE_CONCRETE_INSTRUCTION(MathMinMax)
 
  protected:
-  virtual bool DataEquals(HValue* other) {
+  virtual bool DataEquals(HValue* other) V8_OVERRIDE {
     return other->IsMathMinMax() &&
         HMathMinMax::cast(other)->operation_ == operation_;
   }
 
-  virtual Range* InferRange(Zone* zone);
+  virtual Range* InferRange(Zone* zone) V8_OVERRIDE;
 
  private:
   HMathMinMax(HValue* context, HValue* left, HValue* right, Operation op)
       : HArithmeticBinaryOperation(context, left, right),
         operation_(op) { }
 
   Operation operation_;
 };
 
 
-class HBitwise: public HBitwiseBinaryOperation {
+class HBitwise V8_FINAL : public HBitwiseBinaryOperation {
  public:
   static HInstruction* New(Zone* zone,
                            HValue* context,
                            Token::Value op,
                            HValue* left,
                            HValue* right);
 
   Token::Value op() const { return op_; }
 
-  virtual bool IsCommutative() const { return true; }
+  virtual bool IsCommutative() const V8_OVERRIDE { return true; }
 
-  virtual HValue* Canonicalize();
+  virtual HValue* Canonicalize() V8_OVERRIDE;
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
   DECLARE_CONCRETE_INSTRUCTION(Bitwise)
 
  protected:
-  virtual bool DataEquals(HValue* other) {
+  virtual bool DataEquals(HValue* other) V8_OVERRIDE {
     return op() == HBitwise::cast(other)->op();
   }
 
-  virtual Range* InferRange(Zone* zone);
+  virtual Range* InferRange(Zone* zone) V8_OVERRIDE;
 
  private:
   HBitwise(HValue* context,
            Token::Value op,
            HValue* left,
            HValue* right)
       : HBitwiseBinaryOperation(context, left, right, HType::TaggedNumber()),
         op_(op) {
     ASSERT(op == Token::BIT_AND || op == Token::BIT_OR || op == Token::BIT_XOR);
     // BIT_AND with a smi-range positive value will always unset the
@@ skipping 16 matching lines @@
           right->representation().IsSmi() &&
           HConstant::cast(right)->Integer32Value() < 0))) {
       SetFlag(kTruncatingToSmi);
     }
   }
 
   Token::Value op_;
 };
 
 
-class HShl: public HBitwiseBinaryOperation {
+class HShl V8_FINAL : public HBitwiseBinaryOperation {
  public:
   static HInstruction* New(Zone* zone,
                            HValue* context,
                            HValue* left,
                            HValue* right);
 
-  virtual Range* InferRange(Zone* zone);
+  virtual Range* InferRange(Zone* zone) V8_OVERRIDE;
 
   virtual void UpdateRepresentation(Representation new_rep,
                                     HInferRepresentationPhase* h_infer,
-                                    const char* reason) {
+                                    const char* reason) V8_OVERRIDE {
     if (new_rep.IsSmi() &&
         !(right()->IsInteger32Constant() &&
           right()->GetInteger32Constant() >= 0)) {
       new_rep = Representation::Integer32();
     }
     HBitwiseBinaryOperation::UpdateRepresentation(new_rep, h_infer, reason);
   }
 
   DECLARE_CONCRETE_INSTRUCTION(Shl)
 
  protected:
-  virtual bool DataEquals(HValue* other) { return true; }
+  virtual bool DataEquals(HValue* other) V8_OVERRIDE { return true; }
 
  private:
   HShl(HValue* context, HValue* left, HValue* right)
       : HBitwiseBinaryOperation(context, left, right) { }
 };
 
 
-class HShr: public HBitwiseBinaryOperation {
+class HShr V8_FINAL : public HBitwiseBinaryOperation {
  public:
   static HInstruction* New(Zone* zone,
                            HValue* context,
                            HValue* left,
                            HValue* right);
 
-  virtual bool TryDecompose(DecompositionResult* decomposition) {
+  virtual bool TryDecompose(DecompositionResult* decomposition) V8_OVERRIDE {
     if (right()->IsInteger32Constant()) {
       if (decomposition->Apply(left(), 0, right()->GetInteger32Constant())) {
         // This is intended to look for HAdd and HSub, to handle compounds
         // like ((base + offset) >> scale) with one single decomposition.
         left()->TryDecompose(decomposition);
         return true;
       }
     }
     return false;
   }
 
-  virtual Range* InferRange(Zone* zone);
+  virtual Range* InferRange(Zone* zone) V8_OVERRIDE;
 
   virtual void UpdateRepresentation(Representation new_rep,
                                     HInferRepresentationPhase* h_infer,
-                                    const char* reason) {
+                                    const char* reason) V8_OVERRIDE {
     if (new_rep.IsSmi()) new_rep = Representation::Integer32();
     HBitwiseBinaryOperation::UpdateRepresentation(new_rep, h_infer, reason);
   }
 
   DECLARE_CONCRETE_INSTRUCTION(Shr)
 
  protected:
-  virtual bool DataEquals(HValue* other) { return true; }
+  virtual bool DataEquals(HValue* other) V8_OVERRIDE { return true; }
 
  private:
   HShr(HValue* context, HValue* left, HValue* right)
       : HBitwiseBinaryOperation(context, left, right) { }
 };
 
 
-class HSar: public HBitwiseBinaryOperation {
+class HSar V8_FINAL : public HBitwiseBinaryOperation {
  public:
   static HInstruction* New(Zone* zone,
                            HValue* context,
                            HValue* left,
                            HValue* right);
 
-  virtual bool TryDecompose(DecompositionResult* decomposition) {
+  virtual bool TryDecompose(DecompositionResult* decomposition) V8_OVERRIDE {
     if (right()->IsInteger32Constant()) {
       if (decomposition->Apply(left(), 0, right()->GetInteger32Constant())) {
         // This is intended to look for HAdd and HSub, to handle compounds
         // like ((base + offset) >> scale) with one single decomposition.
         left()->TryDecompose(decomposition);
         return true;
       }
     }
     return false;
   }
 
-  virtual Range* InferRange(Zone* zone);
+  virtual Range* InferRange(Zone* zone) V8_OVERRIDE;
 
   virtual void UpdateRepresentation(Representation new_rep,
                                     HInferRepresentationPhase* h_infer,
-                                    const char* reason) {
+                                    const char* reason) V8_OVERRIDE {
     if (new_rep.IsSmi()) new_rep = Representation::Integer32();
     HBitwiseBinaryOperation::UpdateRepresentation(new_rep, h_infer, reason);
   }
 
   DECLARE_CONCRETE_INSTRUCTION(Sar)
 
  protected:
-  virtual bool DataEquals(HValue* other) { return true; }
+  virtual bool DataEquals(HValue* other) V8_OVERRIDE { return true; }
 
  private:
   HSar(HValue* context, HValue* left, HValue* right)
       : HBitwiseBinaryOperation(context, left, right) { }
 };
 
 
-class HRor: public HBitwiseBinaryOperation {
+class HRor V8_FINAL : public HBitwiseBinaryOperation {
  public:
   HRor(HValue* context, HValue* left, HValue* right)
        : HBitwiseBinaryOperation(context, left, right) {
     ChangeRepresentation(Representation::Integer32());
   }
 
   virtual void UpdateRepresentation(Representation new_rep,
                                     HInferRepresentationPhase* h_infer,
-                                    const char* reason) {
+                                    const char* reason) V8_OVERRIDE {
     if (new_rep.IsSmi()) new_rep = Representation::Integer32();
     HBitwiseBinaryOperation::UpdateRepresentation(new_rep, h_infer, reason);
   }
 
   DECLARE_CONCRETE_INSTRUCTION(Ror)
 
  protected:
-  virtual bool DataEquals(HValue* other) { return true; }
+  virtual bool DataEquals(HValue* other) V8_OVERRIDE { return true; }
 };
 
 
-class HOsrEntry: public HTemplateInstruction<0> {
+class HOsrEntry V8_FINAL : public HTemplateInstruction<0> {
  public:
   DECLARE_INSTRUCTION_FACTORY_P1(HOsrEntry, BailoutId);
 
   BailoutId ast_id() const { return ast_id_; }
 
-  virtual Representation RequiredInputRepresentation(int index) {
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     return Representation::None();
   }
 
   DECLARE_CONCRETE_INSTRUCTION(OsrEntry)
 
  private:
   explicit HOsrEntry(BailoutId ast_id) : ast_id_(ast_id) {
     SetGVNFlag(kChangesOsrEntries);
     SetGVNFlag(kChangesNewSpacePromotion);
   }
 
   BailoutId ast_id_;
 };
 
 
-class HParameter: public HTemplateInstruction<0> {
+class HParameter V8_FINAL : public HTemplateInstruction<0> {
  public:
   enum ParameterKind {
     STACK_PARAMETER,
     REGISTER_PARAMETER
   };
 
   DECLARE_INSTRUCTION_FACTORY_P1(HParameter, unsigned);
   DECLARE_INSTRUCTION_FACTORY_P2(HParameter, unsigned, ParameterKind);
   DECLARE_INSTRUCTION_FACTORY_P3(HParameter, unsigned, ParameterKind,
                                  Representation);
 
   unsigned index() const { return index_; }
   ParameterKind kind() const { return kind_; }
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
-  virtual Representation RequiredInputRepresentation(int index) {
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     return Representation::None();
   }
 
   DECLARE_CONCRETE_INSTRUCTION(Parameter)
 
  private:
   explicit HParameter(unsigned index,
                       ParameterKind kind = STACK_PARAMETER)
       : index_(index),
         kind_(kind) {
     set_representation(Representation::Tagged());
   }
 
   explicit HParameter(unsigned index,
                       ParameterKind kind,
                       Representation r)
       : index_(index),
         kind_(kind) {
     set_representation(r);
   }
 
   unsigned index_;
   ParameterKind kind_;
 };
 
 
-class HCallStub: public HUnaryCall {
+class HCallStub V8_FINAL : public HUnaryCall {
  public:
   HCallStub(HValue* context, CodeStub::Major major_key, int argument_count)
       : HUnaryCall(context, argument_count),
         major_key_(major_key),
         transcendental_type_(TranscendentalCache::kNumberOfCaches) {
   }
 
   CodeStub::Major major_key() { return major_key_; }
 
   HValue* context() { return value(); }
 
   void set_transcendental_type(TranscendentalCache::Type transcendental_type) {
     transcendental_type_ = transcendental_type;
   }
   TranscendentalCache::Type transcendental_type() {
     return transcendental_type_;
   }
 
-  virtual void PrintDataTo(StringStream* stream);
-
-  virtual Representation RequiredInputRepresentation(int index) {
-    return Representation::Tagged();
-  }
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
   DECLARE_CONCRETE_INSTRUCTION(CallStub)
 
  private:
   CodeStub::Major major_key_;
   TranscendentalCache::Type transcendental_type_;
 };
 
 
-class HUnknownOSRValue: public HTemplateInstruction<0> {
+class HUnknownOSRValue V8_FINAL : public HTemplateInstruction<0> {
  public:
   DECLARE_INSTRUCTION_FACTORY_P0(HUnknownOSRValue)
 
-  virtual Representation RequiredInputRepresentation(int index) {
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     return Representation::None();
   }
 
   void set_incoming_value(HPhi* value) {
     incoming_value_ = value;
   }
 
   HPhi* incoming_value() {
     return incoming_value_;
   }
 
-  virtual Representation KnownOptimalRepresentation() {
+  virtual Representation KnownOptimalRepresentation() V8_OVERRIDE {
     if (incoming_value_ == NULL) return Representation::None();
     return incoming_value_->KnownOptimalRepresentation();
   }
 
   DECLARE_CONCRETE_INSTRUCTION(UnknownOSRValue)
 
  private:
   HUnknownOSRValue()
       : incoming_value_(NULL) {
     set_representation(Representation::Tagged());
   }
 
   HPhi* incoming_value_;
 };
 
 
-class HLoadGlobalCell: public HTemplateInstruction<0> {
+class HLoadGlobalCell V8_FINAL : public HTemplateInstruction<0> {
  public:
   HLoadGlobalCell(Handle<Cell> cell, PropertyDetails details)
       : cell_(cell), details_(details), unique_id_() {
     set_representation(Representation::Tagged());
     SetFlag(kUseGVN);
     SetGVNFlag(kDependsOnGlobalVars);
   }
 
   Handle<Cell> cell() const { return cell_; }
   bool RequiresHoleCheck() const;
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
-  virtual intptr_t Hashcode() {
+  virtual intptr_t Hashcode() V8_OVERRIDE {
     return unique_id_.Hashcode();
   }
 
-  virtual void FinalizeUniqueValueId() {
+  virtual void FinalizeUniqueValueId() V8_OVERRIDE {
     unique_id_ = UniqueValueId(cell_);
   }
 
-  virtual Representation RequiredInputRepresentation(int index) {
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     return Representation::None();
   }
 
   DECLARE_CONCRETE_INSTRUCTION(LoadGlobalCell)
 
  protected:
-  virtual bool DataEquals(HValue* other) {
+  virtual bool DataEquals(HValue* other) V8_OVERRIDE {
     HLoadGlobalCell* b = HLoadGlobalCell::cast(other);
     return unique_id_ == b->unique_id_;
   }
 
  private:
-  virtual bool IsDeletable() const { return !RequiresHoleCheck(); }
+  virtual bool IsDeletable() const V8_OVERRIDE { return !RequiresHoleCheck(); }
 
   Handle<Cell> cell_;
   PropertyDetails details_;
   UniqueValueId unique_id_;
 };
 
 
-class HLoadGlobalGeneric: public HTemplateInstruction<2> {
+class HLoadGlobalGeneric V8_FINAL : public HTemplateInstruction<2> {
  public:
   HLoadGlobalGeneric(HValue* context,
                      HValue* global_object,
                      Handle<Object> name,
                      bool for_typeof)
       : name_(name),
         for_typeof_(for_typeof) {
     SetOperandAt(0, context);
     SetOperandAt(1, global_object);
     set_representation(Representation::Tagged());
     SetAllSideEffects();
   }
 
   HValue* context() { return OperandAt(0); }
   HValue* global_object() { return OperandAt(1); }
   Handle<Object> name() const { return name_; }
   bool for_typeof() const { return for_typeof_; }
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
-  virtual Representation RequiredInputRepresentation(int index) {
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     return Representation::Tagged();
   }
 
   DECLARE_CONCRETE_INSTRUCTION(LoadGlobalGeneric)
 
  private:
   Handle<Object> name_;
   bool for_typeof_;
 };
 
 
-class HAllocate: public HTemplateInstruction<2> {
+class HAllocate V8_FINAL : public HTemplateInstruction<2> {
  public:
   static HAllocate* New(Zone* zone,
                         HValue* context,
                         HValue* size,
                         HType type,
                         PretenureFlag pretenure_flag,
                         InstanceType instance_type) {
     return new(zone) HAllocate(context, size, type, pretenure_flag,
         instance_type);
   }
 
   // Maximum instance size for which allocations will be inlined.
   static const int kMaxInlineSize = 64 * kPointerSize;
 
   HValue* context() { return OperandAt(0); }
   HValue* size() { return OperandAt(1); }
 
-  virtual Representation RequiredInputRepresentation(int index) {
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     if (index == 0) {
       return Representation::Tagged();
     } else {
       return Representation::Integer32();
     }
   }
 
   virtual Handle<Map> GetMonomorphicJSObjectMap() {
     return known_initial_map_;
   }
@@ skipping 28 matching lines @@
 
   void MakeDoubleAligned() {
     flags_ = static_cast<HAllocate::Flags>(flags_ | ALLOCATE_DOUBLE_ALIGNED);
   }
 
   void UpdateSize(HValue* size) {
     SetOperandAt(1, size);
   }
 
   virtual void HandleSideEffectDominator(GVNFlag side_effect,
-                                         HValue* dominator);
+                                         HValue* dominator) V8_OVERRIDE;
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
   DECLARE_CONCRETE_INSTRUCTION(Allocate)
 
  private:
   enum Flags {
     ALLOCATE_IN_NEW_SPACE = 1 << 0,
     ALLOCATE_IN_OLD_DATA_SPACE = 1 << 1,
     ALLOCATE_IN_OLD_POINTER_SPACE = 1 << 2,
     ALLOCATE_DOUBLE_ALIGNED = 1 << 3,
     PREFILL_WITH_FILLER = 1 << 4
@@ skipping 19 matching lines @@
       flags_ = static_cast<HAllocate::Flags>(flags_ |
           ALLOCATE_DOUBLE_ALIGNED);
     }
   }
 
   Flags flags_;
   Handle<Map> known_initial_map_;
 };
 
 
-class HInnerAllocatedObject: public HTemplateInstruction<1> {
+class HInnerAllocatedObject V8_FINAL : public HTemplateInstruction<1> {
  public:
   static HInnerAllocatedObject* New(Zone* zone,
                                     HValue* context,
                                     HValue* value,
                                     int offset,
                                     HType type = HType::Tagged()) {
     return new(zone) HInnerAllocatedObject(value, offset, type);
   }
 
   HValue* base_object() { return OperandAt(0); }
   int offset() { return offset_; }
 
-  virtual Representation RequiredInputRepresentation(int index) {
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     return Representation::Tagged();
   }
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
   DECLARE_CONCRETE_INSTRUCTION(InnerAllocatedObject)
 
  private:
   HInnerAllocatedObject(HValue* value, int offset, HType type = HType::Tagged())
       : HTemplateInstruction<1>(type), offset_(offset) {
     ASSERT(value->IsAllocate());
     SetOperandAt(0, value);
     set_type(type);
     set_representation(Representation::Tagged());
@@ skipping 26 matching lines @@
     return false;
   }
   if (object != new_space_dominator) return true;
   if (object->IsAllocate()) {
     return !HAllocate::cast(object)->IsNewSpaceAllocation();
   }
   return true;
 }
 
 
-class HStoreGlobalCell: public HUnaryOperation {
+class HStoreGlobalCell V8_FINAL : public HUnaryOperation {
  public:
   DECLARE_INSTRUCTION_FACTORY_P3(HStoreGlobalCell, HValue*,
                                  Handle<PropertyCell>, PropertyDetails);
 
   Handle<PropertyCell> cell() const { return cell_; }
   bool RequiresHoleCheck() {
     return !details_.IsDontDelete() || details_.IsReadOnly();
   }
   bool NeedsWriteBarrier() {
     return StoringValueNeedsWriteBarrier(value());
   }
 
-  virtual Representation RequiredInputRepresentation(int index) {
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     return Representation::Tagged();
   }
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
   DECLARE_CONCRETE_INSTRUCTION(StoreGlobalCell)
 
  private:
   HStoreGlobalCell(HValue* value,
                    Handle<PropertyCell> cell,
                    PropertyDetails details)
       : HUnaryOperation(value),
         cell_(cell),
         details_(details) {
     SetGVNFlag(kChangesGlobalVars);
   }
 
   Handle<PropertyCell> cell_;
   PropertyDetails details_;
 };
 
 
-class HStoreGlobalGeneric: public HTemplateInstruction<3> {
+class HStoreGlobalGeneric : public HTemplateInstruction<3> {
  public:
   inline static HStoreGlobalGeneric* New(Zone* zone,
                                          HValue* context,
                                          HValue* global_object,
                                          Handle<Object> name,
                                          HValue* value,
                                          StrictModeFlag strict_mode_flag) {
     return new(zone) HStoreGlobalGeneric(context, global_object,
                                          name, value, strict_mode_flag);
   }
 
   HValue* context() { return OperandAt(0); }
   HValue* global_object() { return OperandAt(1); }
   Handle<Object> name() const { return name_; }
   HValue* value() { return OperandAt(2); }
   StrictModeFlag strict_mode_flag() { return strict_mode_flag_; }
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
-  virtual Representation RequiredInputRepresentation(int index) {
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     return Representation::Tagged();
   }
 
   DECLARE_CONCRETE_INSTRUCTION(StoreGlobalGeneric)
 
  private:
   HStoreGlobalGeneric(HValue* context,
                       HValue* global_object,
                       Handle<Object> name,
                       HValue* value,
                       StrictModeFlag strict_mode_flag)
       : name_(name),
         strict_mode_flag_(strict_mode_flag) {
     SetOperandAt(0, context);
     SetOperandAt(1, global_object);
     SetOperandAt(2, value);
     set_representation(Representation::Tagged());
     SetAllSideEffects();
   }
 
   Handle<Object> name_;
   StrictModeFlag strict_mode_flag_;
 };
 
 
-class HLoadContextSlot: public HUnaryOperation {
+class HLoadContextSlot V8_FINAL : public HUnaryOperation {
  public:
   enum Mode {
     // Perform a normal load of the context slot without checking its value.
     kNoCheck,
     // Load and check the value of the context slot. Deoptimize if it's the
     // hole value. This is used for checking for loading of uninitialized
     // harmony bindings where we deoptimize into full-codegen generated code
     // which will subsequently throw a reference error.
     kCheckDeoptimize,
     // Load and check the value of the context slot. Return undefined if it's
@@ skipping 24 matching lines @@
   Mode mode() const { return mode_; }
 
   bool DeoptimizesOnHole() {
     return mode_ == kCheckDeoptimize;
   }
 
   bool RequiresHoleCheck() const {
     return mode_ != kNoCheck;
   }
 
-  virtual Representation RequiredInputRepresentation(int index) {
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     return Representation::Tagged();
   }
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
   DECLARE_CONCRETE_INSTRUCTION(LoadContextSlot)
 
  protected:
-  virtual bool DataEquals(HValue* other) {
+  virtual bool DataEquals(HValue* other) V8_OVERRIDE {
     HLoadContextSlot* b = HLoadContextSlot::cast(other);
     return (slot_index() == b->slot_index());
   }
 
  private:
-  virtual bool IsDeletable() const { return !RequiresHoleCheck(); }
+  virtual bool IsDeletable() const V8_OVERRIDE { return !RequiresHoleCheck(); }
 
   int slot_index_;
   Mode mode_;
 };
 
 
-class HStoreContextSlot: public HTemplateInstruction<2> {
+class HStoreContextSlot V8_FINAL : public HTemplateInstruction<2> {
  public:
   enum Mode {
     // Perform a normal store to the context slot without checking its previous
     // value.
     kNoCheck,
     // Check the previous value of the context slot and deoptimize if it's the
     // hole value. This is used for checking for assignments to uninitialized
     // harmony bindings where we deoptimize into full-codegen generated code
     // which will subsequently throw a reference error.
     kCheckDeoptimize,
@@ skipping 14 matching lines @@
   }
 
   bool DeoptimizesOnHole() {
     return mode_ == kCheckDeoptimize;
   }
 
   bool RequiresHoleCheck() {
     return mode_ != kNoCheck;
   }
 
-  virtual Representation RequiredInputRepresentation(int index) {
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     return Representation::Tagged();
   }
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
   DECLARE_CONCRETE_INSTRUCTION(StoreContextSlot)
 
  private:
   HStoreContextSlot(HValue* context, int slot_index, Mode mode, HValue* value)
       : slot_index_(slot_index), mode_(mode) {
     SetOperandAt(0, context);
     SetOperandAt(1, value);
     SetGVNFlag(kChangesContextSlots);
   }
 
   int slot_index_;
   Mode mode_;
 };
 
 
 // Represents an access to a portion of an object, such as the map pointer,
 // array elements pointer, etc, but not accesses to array elements themselves.
-class HObjectAccess {
+class HObjectAccess V8_FINAL {
  public:
   inline bool IsInobject() const {
     return portion() != kBackingStore && portion() != kExternalMemory;
   }
 
   inline bool IsExternalMemory() const {
     return portion() == kExternalMemory;
   }
 
   inline bool IsStringLength() const {
@@ skipping 154 matching lines @@
 
   friend class HLoadNamedField;
   friend class HStoreNamedField;
 
   inline Portion portion() const {
     return PortionField::decode(value_);
   }
 };
 
 
-class HLoadNamedField: public HTemplateInstruction<2> {
+class HLoadNamedField V8_FINAL : public HTemplateInstruction<2> {
  public:
   DECLARE_INSTRUCTION_FACTORY_P2(HLoadNamedField, HValue*, HObjectAccess);
   DECLARE_INSTRUCTION_FACTORY_P3(HLoadNamedField, HValue*, HObjectAccess,
                                  HValue*);
 
   HValue* object() { return OperandAt(0); }
   HValue* typecheck() {
     ASSERT(HasTypeCheck());
     return OperandAt(1);
   }
 
   bool HasTypeCheck() const { return OperandAt(0) != OperandAt(1); }
+  void ClearTypeCheck() { SetOperandAt(1, object()); }
   HObjectAccess access() const { return access_; }
   Representation field_representation() const {
       return access_.representation();
   }
 
-  virtual bool HasEscapingOperandAt(int index) { return false; }
-  virtual Representation RequiredInputRepresentation(int index) {
+  virtual bool HasEscapingOperandAt(int index) V8_OVERRIDE { return false; }
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     if (index == 0 && access().IsExternalMemory()) {
       // object must be external in case of external memory access
       return Representation::External();
     }
     return Representation::Tagged();
   }
-  virtual Range* InferRange(Zone* zone);
-  virtual void PrintDataTo(StringStream* stream);
+  virtual Range* InferRange(Zone* zone) V8_OVERRIDE;
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
   DECLARE_CONCRETE_INSTRUCTION(LoadNamedField)
 
  protected:
-  virtual bool DataEquals(HValue* other) {
+  virtual bool DataEquals(HValue* other) V8_OVERRIDE {
     HLoadNamedField* b = HLoadNamedField::cast(other);
     return access_.Equals(b->access_);
   }
 
  private:
   HLoadNamedField(HValue* object,
                   HObjectAccess access,
                   HValue* typecheck = NULL)
       : access_(access) {
     ASSERT(object != NULL);
@@ skipping 11 matching lines @@
     } else if (FLAG_track_heap_object_fields &&
                representation.IsHeapObject()) {
       set_type(HType::NonPrimitive());
       set_representation(Representation::Tagged());
     } else {
       set_representation(Representation::Tagged());
     }
     access.SetGVNFlags(this, false);
   }
 
-  virtual bool IsDeletable() const { return true; }
+  virtual bool IsDeletable() const V8_OVERRIDE { return true; }
 
   HObjectAccess access_;
 };
 
 
-class HLoadNamedFieldPolymorphic: public HTemplateInstruction<2> {
- public:
-  HLoadNamedFieldPolymorphic(HValue* context,
-                             HValue* object,
-                             SmallMapList* types,
-                             Handle<String> name,
-                             Zone* zone);
-
-  HValue* context() { return OperandAt(0); }
-  HValue* object() { return OperandAt(1); }
-  SmallMapList* types() { return &types_; }
-  Handle<String> name() { return name_; }
-  bool need_generic() { return need_generic_; }
-
-  virtual Representation RequiredInputRepresentation(int index) {
-    return Representation::Tagged();
-  }
-
-  virtual void PrintDataTo(StringStream* stream);
-
-  DECLARE_CONCRETE_INSTRUCTION(LoadNamedFieldPolymorphic)
-
-  static const int kMaxLoadPolymorphism = 4;
-
-  virtual void FinalizeUniqueValueId();
-
- protected:
-  virtual bool DataEquals(HValue* value);
-
- private:
-  SmallMapList types_;
-  Handle<String> name_;
-  ZoneList<UniqueValueId> types_unique_ids_;
-  UniqueValueId name_unique_id_;
-  bool need_generic_;
-};
-
-
-
-class HLoadNamedGeneric: public HTemplateInstruction<2> {
+class HLoadNamedGeneric V8_FINAL : public HTemplateInstruction<2> {
  public:
   HLoadNamedGeneric(HValue* context, HValue* object, Handle<Object> name)
       : name_(name) {
     SetOperandAt(0, context);
     SetOperandAt(1, object);
     set_representation(Representation::Tagged());
     SetAllSideEffects();
   }
 
   HValue* context() { return OperandAt(0); }
   HValue* object() { return OperandAt(1); }
   Handle<Object> name() const { return name_; }
 
-  virtual Representation RequiredInputRepresentation(int index) {
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     return Representation::Tagged();
   }
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
   DECLARE_CONCRETE_INSTRUCTION(LoadNamedGeneric)
 
  private:
   Handle<Object> name_;
 };
 
 
-class HLoadFunctionPrototype: public HUnaryOperation {
+class HLoadFunctionPrototype V8_FINAL : public HUnaryOperation {
  public:
   explicit HLoadFunctionPrototype(HValue* function)
       : HUnaryOperation(function) {
     set_representation(Representation::Tagged());
     SetFlag(kUseGVN);
     SetGVNFlag(kDependsOnCalls);
   }
 
   HValue* function() { return OperandAt(0); }
 
-  virtual Representation RequiredInputRepresentation(int index) {
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     return Representation::Tagged();
   }
 
   DECLARE_CONCRETE_INSTRUCTION(LoadFunctionPrototype)
 
  protected:
-  virtual bool DataEquals(HValue* other) { return true; }
+  virtual bool DataEquals(HValue* other) V8_OVERRIDE { return true; }
 };
 
 class ArrayInstructionInterface {
  public:
   virtual HValue* GetKey() = 0;
   virtual void SetKey(HValue* key) = 0;
   virtual void SetIndexOffset(uint32_t index_offset) = 0;
   virtual bool IsDehoisted() = 0;
   virtual void SetDehoisted(bool is_dehoisted) = 0;
   virtual ~ArrayInstructionInterface() { };
 
   static Representation KeyedAccessIndexRequirement(Representation r) {
     return r.IsInteger32() || kSmiValueSize != 31
         ? Representation::Integer32() : Representation::Smi();
   }
 };
 
 
 enum LoadKeyedHoleMode {
   NEVER_RETURN_HOLE,
   ALLOW_RETURN_HOLE
 };
 
 
-class HLoadKeyed
+class HLoadKeyed V8_FINAL
     : public HTemplateInstruction<3>, public ArrayInstructionInterface {
  public:
   DECLARE_INSTRUCTION_FACTORY_P4(HLoadKeyed, HValue*, HValue*, HValue*,
                                  ElementsKind);
   DECLARE_INSTRUCTION_FACTORY_P5(HLoadKeyed, HValue*, HValue*, HValue*,
                                  ElementsKind, LoadKeyedHoleMode);
 
   bool is_external() const {
     return IsExternalArrayElementsKind(elements_kind());
   }
@@ skipping 14 matching lines @@
   void SetDehoisted(bool is_dehoisted) {
     bit_field_ = IsDehoistedField::update(bit_field_, is_dehoisted);
   }
   ElementsKind elements_kind() const {
     return ElementsKindField::decode(bit_field_);
   }
   LoadKeyedHoleMode hole_mode() const {
     return HoleModeField::decode(bit_field_);
   }
 
-  virtual Representation RequiredInputRepresentation(int index) {
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     // kind_fast:       tagged[int32] (none)
     // kind_double:     tagged[int32] (none)
     // kind_external: external[int32] (none)
     if (index == 0) {
       return is_external() ? Representation::External()
           : Representation::Tagged();
     }
     if (index == 1) {
       return ArrayInstructionInterface::KeyedAccessIndexRequirement(
           OperandAt(1)->representation());
     }
     return Representation::None();
   }
 
-  virtual Representation observed_input_representation(int index) {
+  virtual Representation observed_input_representation(int index) V8_OVERRIDE {
     return RequiredInputRepresentation(index);
   }
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
   bool UsesMustHandleHole() const;
   bool AllUsesCanTreatHoleAsNaN() const;
   bool RequiresHoleCheck() const;
 
-  virtual Range* InferRange(Zone* zone);
+  virtual Range* InferRange(Zone* zone) V8_OVERRIDE;
 
   DECLARE_CONCRETE_INSTRUCTION(LoadKeyed)
 
  protected:
-  virtual bool DataEquals(HValue* other) {
+  virtual bool DataEquals(HValue* other) V8_OVERRIDE {
     if (!other->IsLoadKeyed()) return false;
     HLoadKeyed* other_load = HLoadKeyed::cast(other);
 
     if (IsDehoisted() && index_offset() != other_load->index_offset())
       return false;
     return elements_kind() == other_load->elements_kind();
   }
 
  private:
   HLoadKeyed(HValue* obj,
@@ skipping 39 matching lines @@
       }
 
       SetGVNFlag(kDependsOnExternalMemory);
       // Native code could change the specialized array.
       SetGVNFlag(kDependsOnCalls);
     }
 
     SetFlag(kUseGVN);
   }
 
-  virtual bool IsDeletable() const {
+  virtual bool IsDeletable() const V8_OVERRIDE {
     return !RequiresHoleCheck();
   }
 
   // Establish some checks around our packed fields
   enum LoadKeyedBits {
     kBitsForElementsKind = 5,
     kBitsForHoleMode = 1,
     kBitsForIndexOffset = 25,
     kBitsForIsDehoisted = 1,
 
@@ skipping 15 matching lines @@
   class IndexOffsetField:
     public BitField<uint32_t, kStartIndexOffset, kBitsForIndexOffset>
     {};  // NOLINT
   class IsDehoistedField:
     public BitField<bool, kStartIsDehoisted, kBitsForIsDehoisted>
     {};  // NOLINT
   uint32_t bit_field_;
 };
 
 
-class HLoadKeyedGeneric: public HTemplateInstruction<3> {
+class HLoadKeyedGeneric V8_FINAL : public HTemplateInstruction<3> {
  public:
   HLoadKeyedGeneric(HValue* context, HValue* obj, HValue* key) {
     set_representation(Representation::Tagged());
     SetOperandAt(0, obj);
     SetOperandAt(1, key);
     SetOperandAt(2, context);
     SetAllSideEffects();
   }
 
   HValue* object() { return OperandAt(0); }
   HValue* key() { return OperandAt(1); }
   HValue* context() { return OperandAt(2); }
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
-  virtual Representation RequiredInputRepresentation(int index) {
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     // tagged[tagged]
     return Representation::Tagged();
   }
 
-  virtual HValue* Canonicalize();
+  virtual HValue* Canonicalize() V8_OVERRIDE;
 
   DECLARE_CONCRETE_INSTRUCTION(LoadKeyedGeneric)
 };
 
 
-class HStoreNamedField: public HTemplateInstruction<3> {
+class HStoreNamedField V8_FINAL : public HTemplateInstruction<3> {
  public:
   DECLARE_INSTRUCTION_FACTORY_P3(HStoreNamedField, HValue*,
                                  HObjectAccess, HValue*);
 
   DECLARE_CONCRETE_INSTRUCTION(StoreNamedField)
 
-  virtual bool HasEscapingOperandAt(int index) { return index == 1; }
-  virtual Representation RequiredInputRepresentation(int index) {
+  virtual bool HasEscapingOperandAt(int index) V8_OVERRIDE {
+    return index == 1;
+  }
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     if (index == 0 && access().IsExternalMemory()) {
       // object must be external in case of external memory access
       return Representation::External();
     } else if (index == 1 &&
         (field_representation().IsDouble() ||
          field_representation().IsSmi() ||
          field_representation().IsInteger32())) {
       return field_representation();
     }
     return Representation::Tagged();
   }
   virtual void HandleSideEffectDominator(GVNFlag side_effect,
-                                         HValue* dominator) {
+                                         HValue* dominator) V8_OVERRIDE {
     ASSERT(side_effect == kChangesNewSpacePromotion);
     new_space_dominator_ = dominator;
   }
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
   void SkipWriteBarrier() { write_barrier_mode_ = SKIP_WRITE_BARRIER; }
   bool IsSkipWriteBarrier() const {
     return write_barrier_mode_ == SKIP_WRITE_BARRIER;
   }
 
   HValue* object() const { return OperandAt(0); }
   HValue* value() const { return OperandAt(1); }
   HValue* transition() const { return OperandAt(2); }
 
@@ skipping 54 matching lines @@
     access.SetGVNFlags(this, true);
   }
 
   HObjectAccess access_;
   HValue* new_space_dominator_;
   WriteBarrierMode write_barrier_mode_ : 1;
   bool has_transition_ : 1;
 };
 
 
-class HStoreNamedGeneric: public HTemplateInstruction<3> {
+class HStoreNamedGeneric V8_FINAL : public HTemplateInstruction<3> {
  public:
   HStoreNamedGeneric(HValue* context,
                      HValue* object,
                      Handle<String> name,
                      HValue* value,
                      StrictModeFlag strict_mode_flag)
       : name_(name),
         strict_mode_flag_(strict_mode_flag) {
     SetOperandAt(0, object);
     SetOperandAt(1, value);
     SetOperandAt(2, context);
     SetAllSideEffects();
   }
 
   HValue* object() { return OperandAt(0); }
   HValue* value() { return OperandAt(1); }
   HValue* context() { return OperandAt(2); }
   Handle<String> name() { return name_; }
   StrictModeFlag strict_mode_flag() { return strict_mode_flag_; }
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
-  virtual Representation RequiredInputRepresentation(int index) {
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     return Representation::Tagged();
   }
 
   DECLARE_CONCRETE_INSTRUCTION(StoreNamedGeneric)
 
  private:
   Handle<String> name_;
   StrictModeFlag strict_mode_flag_;
 };
 
 
-class HStoreKeyed
+class HStoreKeyed V8_FINAL
     : public HTemplateInstruction<3>, public ArrayInstructionInterface {
  public:
   DECLARE_INSTRUCTION_FACTORY_P4(HStoreKeyed, HValue*, HValue*, HValue*,
                                  ElementsKind);
 
-  virtual Representation RequiredInputRepresentation(int index) {
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     // kind_fast:       tagged[int32] = tagged
     // kind_double:     tagged[int32] = double
     // kind_smi   :     tagged[int32] = smi
     // kind_external: external[int32] = (double | int32)
     if (index == 0) {
       return is_external() ? Representation::External()
                            : Representation::Tagged();
     } else if (index == 1) {
       return ArrayInstructionInterface::KeyedAccessIndexRequirement(
           OperandAt(1)->representation());
     }
 
     ASSERT_EQ(index, 2);
     if (IsDoubleOrFloatElementsKind(elements_kind())) {
       return Representation::Double();
     }
 
     if (IsFastSmiElementsKind(elements_kind())) {
       return Representation::Smi();
     }
 
     return is_external() ? Representation::Integer32()
                          : Representation::Tagged();
   }
 
   bool is_external() const {
     return IsExternalArrayElementsKind(elements_kind());
   }
 
-  virtual Representation observed_input_representation(int index) {
+  virtual Representation observed_input_representation(int index) V8_OVERRIDE {
     if (index < 2) return RequiredInputRepresentation(index);
     if (IsUninitialized()) {
       return Representation::None();
     }
     if (IsFastSmiElementsKind(elements_kind())) {
       return Representation::Smi();
     }
     if (IsDoubleOrFloatElementsKind(elements_kind())) {
       return Representation::Double();
     }
@@ skipping 20 matching lines @@
   bool IsUninitialized() { return is_uninitialized_; }
   void SetUninitialized(bool is_uninitialized) {
     is_uninitialized_ = is_uninitialized;
   }
 
   bool IsConstantHoleStore() {
     return value()->IsConstant() && HConstant::cast(value())->IsTheHole();
   }
 
   virtual void HandleSideEffectDominator(GVNFlag side_effect,
-                                         HValue* dominator) {
+                                         HValue* dominator) V8_OVERRIDE {
     ASSERT(side_effect == kChangesNewSpacePromotion);
     new_space_dominator_ = dominator;
   }
 
   HValue* new_space_dominator() const { return new_space_dominator_; }
 
   bool NeedsWriteBarrier() {
     if (value_is_smi()) {
       return false;
     } else {
       return StoringValueNeedsWriteBarrier(value()) &&
           ReceiverObjectNeedsWriteBarrier(elements(), new_space_dominator());
     }
   }
 
   bool NeedsCanonicalization();
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
   DECLARE_CONCRETE_INSTRUCTION(StoreKeyed)
 
  private:
   HStoreKeyed(HValue* obj, HValue* key, HValue* val,
               ElementsKind elements_kind)
       : elements_kind_(elements_kind),
       index_offset_(0),
       is_dehoisted_(false),
       is_uninitialized_(false),
@@ skipping 25 matching lines @@
   }
 
   ElementsKind elements_kind_;
   uint32_t index_offset_;
   bool is_dehoisted_ : 1;
   bool is_uninitialized_ : 1;
   HValue* new_space_dominator_;
 };
 
 
-class HStoreKeyedGeneric: public HTemplateInstruction<4> {
+class HStoreKeyedGeneric V8_FINAL : public HTemplateInstruction<4> {
  public:
   HStoreKeyedGeneric(HValue* context,
                      HValue* object,
                      HValue* key,
                      HValue* value,
                      StrictModeFlag strict_mode_flag)
       : strict_mode_flag_(strict_mode_flag) {
     SetOperandAt(0, object);
     SetOperandAt(1, key);
     SetOperandAt(2, value);
     SetOperandAt(3, context);
     SetAllSideEffects();
   }
 
   HValue* object() { return OperandAt(0); }
   HValue* key() { return OperandAt(1); }
   HValue* value() { return OperandAt(2); }
   HValue* context() { return OperandAt(3); }
   StrictModeFlag strict_mode_flag() { return strict_mode_flag_; }
 
-  virtual Representation RequiredInputRepresentation(int index) {
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     // tagged[tagged] = tagged
     return Representation::Tagged();
   }
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
   DECLARE_CONCRETE_INSTRUCTION(StoreKeyedGeneric)
 
  private:
   StrictModeFlag strict_mode_flag_;
 };
 
 
-class HTransitionElementsKind: public HTemplateInstruction<2> {
+class HTransitionElementsKind V8_FINAL : public HTemplateInstruction<2> {
  public:
   inline static HTransitionElementsKind* New(Zone* zone,
                                              HValue* context,
                                              HValue* object,
                                              Handle<Map> original_map,
                                              Handle<Map> transitioned_map) {
     return new(zone) HTransitionElementsKind(context, object,
                                              original_map, transitioned_map);
   }
 
-  virtual Representation RequiredInputRepresentation(int index) {
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     return Representation::Tagged();
   }
 
   HValue* object() { return OperandAt(0); }
   HValue* context() { return OperandAt(1); }
   Handle<Map> original_map() { return original_map_; }
   Handle<Map> transitioned_map() { return transitioned_map_; }
   ElementsKind from_kind() { return from_kind_; }
   ElementsKind to_kind() { return to_kind_; }
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
-  virtual void FinalizeUniqueValueId() {
+  virtual void FinalizeUniqueValueId() V8_OVERRIDE {
     original_map_unique_id_ = UniqueValueId(original_map_);
     transitioned_map_unique_id_ = UniqueValueId(transitioned_map_);
   }
 
   DECLARE_CONCRETE_INSTRUCTION(TransitionElementsKind)
 
  protected:
-  virtual bool DataEquals(HValue* other) {
+  virtual bool DataEquals(HValue* other) V8_OVERRIDE {
     HTransitionElementsKind* instr = HTransitionElementsKind::cast(other);
     return original_map_unique_id_ == instr->original_map_unique_id_ &&
            transitioned_map_unique_id_ == instr->transitioned_map_unique_id_;
   }
 
  private:
   HTransitionElementsKind(HValue* context,
                           HValue* object,
                           Handle<Map> original_map,
                           Handle<Map> transitioned_map)
       : original_map_(original_map),
         transitioned_map_(transitioned_map),
         original_map_unique_id_(),
         transitioned_map_unique_id_(),
         from_kind_(original_map->elements_kind()),
         to_kind_(transitioned_map->elements_kind()) {
     SetOperandAt(0, object);
     SetOperandAt(1, context);
     SetFlag(kUseGVN);
     SetGVNFlag(kChangesElementsKind);
-    if (original_map->has_fast_double_elements()) {
+    if (!IsSimpleMapChangeTransition(from_kind_, to_kind_)) {
       SetGVNFlag(kChangesElementsPointer);
       SetGVNFlag(kChangesNewSpacePromotion);
     }
-    if (transitioned_map->has_fast_double_elements()) {
-      SetGVNFlag(kChangesElementsPointer);
-      SetGVNFlag(kChangesNewSpacePromotion);
-    }
     set_representation(Representation::Tagged());
   }
 
   Handle<Map> original_map_;
   Handle<Map> transitioned_map_;
   UniqueValueId original_map_unique_id_;
   UniqueValueId transitioned_map_unique_id_;
   ElementsKind from_kind_;
   ElementsKind to_kind_;
 };
 
 
-class HStringAdd: public HBinaryOperation {
+class HStringAdd V8_FINAL : public HBinaryOperation {
  public:
   static HInstruction* New(Zone* zone,
                            HValue* context,
                            HValue* left,
                            HValue* right,
                            StringAddFlags flags = STRING_ADD_CHECK_NONE);
 
   StringAddFlags flags() const { return flags_; }
 
-  virtual Representation RequiredInputRepresentation(int index) {
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     return Representation::Tagged();
   }
 
   DECLARE_CONCRETE_INSTRUCTION(StringAdd)
 
  protected:
-  virtual bool DataEquals(HValue* other) { return true; }
+  virtual bool DataEquals(HValue* other) V8_OVERRIDE { return true; }
 
  private:
   HStringAdd(HValue* context, HValue* left, HValue* right, StringAddFlags flags)
       : HBinaryOperation(context, left, right, HType::String()), flags_(flags) {
     set_representation(Representation::Tagged());
     SetFlag(kUseGVN);
     SetGVNFlag(kDependsOnMaps);
     SetGVNFlag(kChangesNewSpacePromotion);
   }
 
   // No side-effects except possible allocation.
   // NOTE: this instruction _does not_ call ToString() on its inputs.
-  virtual bool IsDeletable() const { return true; }
+  virtual bool IsDeletable() const V8_OVERRIDE { return true; }
 
   const StringAddFlags flags_;
 };
 
 
-class HStringCharCodeAt: public HTemplateInstruction<3> {
+class HStringCharCodeAt V8_FINAL : public HTemplateInstruction<3> {
  public:
   static HStringCharCodeAt* New(Zone* zone,
                                 HValue* context,
                                 HValue* string,
                                 HValue* index) {
     return new(zone) HStringCharCodeAt(context, string, index);
   }
 
   virtual Representation RequiredInputRepresentation(int index) {
     // The index is supposed to be Integer32.
     return index == 2
         ? Representation::Integer32()
         : Representation::Tagged();
   }
 
   HValue* context() const { return OperandAt(0); }
   HValue* string() const { return OperandAt(1); }
   HValue* index() const { return OperandAt(2); }
 
   DECLARE_CONCRETE_INSTRUCTION(StringCharCodeAt)
 
  protected:
-  virtual bool DataEquals(HValue* other) { return true; }
+  virtual bool DataEquals(HValue* other) V8_OVERRIDE { return true; }
 
-  virtual Range* InferRange(Zone* zone) {
+  virtual Range* InferRange(Zone* zone) V8_OVERRIDE {
     return new(zone) Range(0, String::kMaxUtf16CodeUnit);
   }
 
  private:
   HStringCharCodeAt(HValue* context, HValue* string, HValue* index) {
     SetOperandAt(0, context);
     SetOperandAt(1, string);
     SetOperandAt(2, index);
     set_representation(Representation::Integer32());
     SetFlag(kUseGVN);
     SetGVNFlag(kDependsOnMaps);
     SetGVNFlag(kChangesNewSpacePromotion);
   }
 
   // No side effects: runtime function assumes string + number inputs.
-  virtual bool IsDeletable() const { return true; }
+  virtual bool IsDeletable() const V8_OVERRIDE { return true; }
 };
 
 
-class HStringCharFromCode: public HTemplateInstruction<2> {
+class HStringCharFromCode V8_FINAL : public HTemplateInstruction<2> {
  public:
   static HInstruction* New(Zone* zone,
                            HValue* context,
                            HValue* char_code);
 
-  virtual Representation RequiredInputRepresentation(int index) {
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     return index == 0
         ? Representation::Tagged()
         : Representation::Integer32();
   }
 
   HValue* context() const { return OperandAt(0); }
   HValue* value() const { return OperandAt(1); }
 
-  virtual bool DataEquals(HValue* other) { return true; }
+  virtual bool DataEquals(HValue* other) V8_OVERRIDE { return true; }
 
   DECLARE_CONCRETE_INSTRUCTION(StringCharFromCode)
 
  private:
   HStringCharFromCode(HValue* context, HValue* char_code)
       : HTemplateInstruction<2>(HType::String()) {
     SetOperandAt(0, context);
     SetOperandAt(1, char_code);
     set_representation(Representation::Tagged());
     SetFlag(kUseGVN);
     SetGVNFlag(kChangesNewSpacePromotion);
   }
 
-  virtual bool IsDeletable() const {
+  virtual bool IsDeletable() const V8_OVERRIDE {
     return !value()->ToNumberCanBeObserved();
   }
 };
 
 
 template <int V>
-class HMaterializedLiteral: public HTemplateInstruction<V> {
+class HMaterializedLiteral : public HTemplateInstruction<V> {
  public:
   HMaterializedLiteral<V>(int index, int depth, AllocationSiteMode mode)
       : literal_index_(index), depth_(depth), allocation_site_mode_(mode) {
     this->set_representation(Representation::Tagged());
   }
 
   HMaterializedLiteral<V>(int index, int depth)
       : literal_index_(index), depth_(depth),
         allocation_site_mode_(DONT_TRACK_ALLOCATION_SITE) {
     this->set_representation(Representation::Tagged());
   }
 
   int literal_index() const { return literal_index_; }
   int depth() const { return depth_; }
   AllocationSiteMode allocation_site_mode() const {
     return allocation_site_mode_;
   }
 
  private:
-  virtual bool IsDeletable() const { return true; }
+  virtual bool IsDeletable() const V8_FINAL V8_OVERRIDE { return true; }
 
   int literal_index_;
   int depth_;
   AllocationSiteMode allocation_site_mode_;
 };
 
 
-class HRegExpLiteral: public HMaterializedLiteral<1> {
+class HRegExpLiteral V8_FINAL : public HMaterializedLiteral<1> {
  public:
   HRegExpLiteral(HValue* context,
                  Handle<FixedArray> literals,
                  Handle<String> pattern,
                  Handle<String> flags,
                  int literal_index)
       : HMaterializedLiteral<1>(literal_index, 0),
         literals_(literals),
         pattern_(pattern),
         flags_(flags) {
     SetOperandAt(0, context);
     SetAllSideEffects();
     set_type(HType::JSObject());
   }
 
   HValue* context() { return OperandAt(0); }
   Handle<FixedArray> literals() { return literals_; }
   Handle<String> pattern() { return pattern_; }
   Handle<String> flags() { return flags_; }
 
-  virtual Representation RequiredInputRepresentation(int index) {
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     return Representation::Tagged();
   }
 
   DECLARE_CONCRETE_INSTRUCTION(RegExpLiteral)
 
  private:
   Handle<FixedArray> literals_;
   Handle<String> pattern_;
   Handle<String> flags_;
 };
 
 
-class HFunctionLiteral: public HTemplateInstruction<1> {
+class HFunctionLiteral V8_FINAL : public HTemplateInstruction<1> {
  public:
   HFunctionLiteral(HValue* context,
                    Handle<SharedFunctionInfo> shared,
                    bool pretenure)
       : HTemplateInstruction<1>(HType::JSObject()),
         shared_info_(shared),
         pretenure_(pretenure),
         has_no_literals_(shared->num_literals() == 0),
         is_generator_(shared->is_generator()),
         language_mode_(shared->language_mode()) {
     SetOperandAt(0, context);
     set_representation(Representation::Tagged());
     SetGVNFlag(kChangesNewSpacePromotion);
   }
 
   HValue* context() { return OperandAt(0); }
 
-  virtual Representation RequiredInputRepresentation(int index) {
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     return Representation::Tagged();
   }
 
   DECLARE_CONCRETE_INSTRUCTION(FunctionLiteral)
 
   Handle<SharedFunctionInfo> shared_info() const { return shared_info_; }
   bool pretenure() const { return pretenure_; }
   bool has_no_literals() const { return has_no_literals_; }
   bool is_generator() const { return is_generator_; }
   LanguageMode language_mode() const { return language_mode_; }
 
  private:
-  virtual bool IsDeletable() const { return true; }
+  virtual bool IsDeletable() const V8_OVERRIDE { return true; }
 
   Handle<SharedFunctionInfo> shared_info_;
   bool pretenure_ : 1;
   bool has_no_literals_ : 1;
   bool is_generator_ : 1;
   LanguageMode language_mode_;
 };
 
 
-class HTypeof: public HTemplateInstruction<2> {
+class HTypeof V8_FINAL : public HTemplateInstruction<2> {
  public:
   explicit HTypeof(HValue* context, HValue* value) {
     SetOperandAt(0, context);
     SetOperandAt(1, value);
     set_representation(Representation::Tagged());
   }
 
   HValue* context() { return OperandAt(0); }
   HValue* value() { return OperandAt(1); }
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
-  virtual Representation RequiredInputRepresentation(int index) {
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     return Representation::Tagged();
   }
 
   DECLARE_CONCRETE_INSTRUCTION(Typeof)
 
  private:
-  virtual bool IsDeletable() const { return true; }
+  virtual bool IsDeletable() const V8_OVERRIDE { return true; }
 };
 
 
-class HTrapAllocationMemento : public HTemplateInstruction<1> {
+class HTrapAllocationMemento V8_FINAL : public HTemplateInstruction<1> {
  public:
   DECLARE_INSTRUCTION_FACTORY_P1(HTrapAllocationMemento, HValue*);
 
-  virtual Representation RequiredInputRepresentation(int index) {
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     return Representation::Tagged();
   }
 
   HValue* object() { return OperandAt(0); }
 
   DECLARE_CONCRETE_INSTRUCTION(TrapAllocationMemento)
 
  private:
   explicit HTrapAllocationMemento(HValue* obj) {
     SetOperandAt(0, obj);
   }
 };
 
 
-class HToFastProperties: public HUnaryOperation {
+class HToFastProperties V8_FINAL : public HUnaryOperation {
  public:
   DECLARE_INSTRUCTION_FACTORY_P1(HToFastProperties, HValue*);
 
-  virtual Representation RequiredInputRepresentation(int index) {
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     return Representation::Tagged();
   }
 
   DECLARE_CONCRETE_INSTRUCTION(ToFastProperties)
 
  private:
   explicit HToFastProperties(HValue* value) : HUnaryOperation(value) {
-    // This instruction is not marked as having side effects, but
-    // changes the map of the input operand. Use it only when creating
+    set_representation(Representation::Tagged());
+    SetGVNFlag(kChangesNewSpacePromotion);
+
+    // This instruction is not marked as kChangesMaps, but does
+    // change the map of the input operand. Use it only when creating
     // object literals via a runtime call.
     ASSERT(value->IsCallRuntime());
 #ifdef DEBUG
     const Runtime::Function* function = HCallRuntime::cast(value)->function();
     ASSERT(function->function_id == Runtime::kCreateObjectLiteral ||
            function->function_id == Runtime::kCreateObjectLiteralShallow);
 #endif
-    set_representation(Representation::Tagged());
   }
 
-  virtual bool IsDeletable() const { return true; }
+  virtual bool IsDeletable() const V8_OVERRIDE { return true; }
 };
 
 
-class HValueOf: public HUnaryOperation {
+class HValueOf V8_FINAL : public HUnaryOperation {
  public:
   explicit HValueOf(HValue* value) : HUnaryOperation(value) {
     set_representation(Representation::Tagged());
   }
 
-  virtual Representation RequiredInputRepresentation(int index) {
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     return Representation::Tagged();
   }
 
   DECLARE_CONCRETE_INSTRUCTION(ValueOf)
 
  private:
-  virtual bool IsDeletable() const { return true; }
+  virtual bool IsDeletable() const V8_OVERRIDE { return true; }
 };
 
 
-class HDateField: public HUnaryOperation {
+class HDateField V8_FINAL : public HUnaryOperation {
  public:
   HDateField(HValue* date, Smi* index)
       : HUnaryOperation(date), index_(index) {
     set_representation(Representation::Tagged());
   }
 
   Smi* index() const { return index_; }
 
-  virtual Representation RequiredInputRepresentation(int index) {
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     return Representation::Tagged();
   }
 
   DECLARE_CONCRETE_INSTRUCTION(DateField)
 
  private:
   Smi* index_;
 };
 
 
-class HSeqStringSetChar: public HTemplateInstruction<3> {
+class HSeqStringSetChar V8_FINAL : public HTemplateInstruction<3> {
  public:
   HSeqStringSetChar(String::Encoding encoding,
                     HValue* string,
                     HValue* index,
                     HValue* value) : encoding_(encoding) {
     SetOperandAt(0, string);
     SetOperandAt(1, index);
     SetOperandAt(2, value);
     set_representation(Representation::Tagged());
   }
 
   String::Encoding encoding() { return encoding_; }
   HValue* string() { return OperandAt(0); }
   HValue* index() { return OperandAt(1); }
   HValue* value() { return OperandAt(2); }
 
-  virtual Representation RequiredInputRepresentation(int index) {
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     return (index == 0) ? Representation::Tagged()
                         : Representation::Integer32();
   }
 
   DECLARE_CONCRETE_INSTRUCTION(SeqStringSetChar)
 
  private:
   String::Encoding encoding_;
 };
 
 
-class HCheckMapValue: public HTemplateInstruction<2> {
+class HCheckMapValue V8_FINAL : public HTemplateInstruction<2> {
  public:
   DECLARE_INSTRUCTION_FACTORY_P2(HCheckMapValue, HValue*, HValue*);
 
-  virtual Representation RequiredInputRepresentation(int index) {
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     return Representation::Tagged();
   }
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
-  virtual HType CalculateInferredType() {
+  virtual HType CalculateInferredType() V8_OVERRIDE {
     return HType::Tagged();
   }
 
   HValue* value() { return OperandAt(0); }
   HValue* map() { return OperandAt(1); }
 
   DECLARE_CONCRETE_INSTRUCTION(CheckMapValue)
 
  protected:
-  virtual bool DataEquals(HValue* other) {
+  virtual bool DataEquals(HValue* other) V8_OVERRIDE {
     return true;
   }
 
  private:
   HCheckMapValue(HValue* value,
                  HValue* map) {
     SetOperandAt(0, value);
     SetOperandAt(1, map);
     set_representation(Representation::Tagged());
     SetFlag(kUseGVN);
     SetGVNFlag(kDependsOnMaps);
     SetGVNFlag(kDependsOnElementsKind);
   }
 };
 
 
-class HForInPrepareMap : public HTemplateInstruction<2> {
+class HForInPrepareMap V8_FINAL : public HTemplateInstruction<2> {
  public:
   static HForInPrepareMap* New(Zone* zone,
                                HValue* context,
                                HValue* object) {
     return new(zone) HForInPrepareMap(context, object);
   }
 
-  virtual Representation RequiredInputRepresentation(int index) {
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     return Representation::Tagged();
   }
 
   HValue* context() { return OperandAt(0); }
   HValue* enumerable() { return OperandAt(1); }
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
-  virtual HType CalculateInferredType() {
+  virtual HType CalculateInferredType() V8_OVERRIDE {
     return HType::Tagged();
   }
 
   DECLARE_CONCRETE_INSTRUCTION(ForInPrepareMap);
 
  private:
   HForInPrepareMap(HValue* context,
                    HValue* object) {
     SetOperandAt(0, context);
     SetOperandAt(1, object);
     set_representation(Representation::Tagged());
     SetAllSideEffects();
   }
 };
 
 
-class HForInCacheArray : public HTemplateInstruction<2> {
+class HForInCacheArray V8_FINAL : public HTemplateInstruction<2> {
  public:
   DECLARE_INSTRUCTION_FACTORY_P3(HForInCacheArray, HValue*, HValue*, int);
 
-  virtual Representation RequiredInputRepresentation(int index) {
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     return Representation::Tagged();
   }
 
   HValue* enumerable() { return OperandAt(0); }
   HValue* map() { return OperandAt(1); }
   int idx() { return idx_; }
 
   HForInCacheArray* index_cache() {
     return index_cache_;
   }
 
   void set_index_cache(HForInCacheArray* index_cache) {
     index_cache_ = index_cache;
   }
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
-  virtual HType CalculateInferredType() {
+  virtual HType CalculateInferredType() V8_OVERRIDE {
     return HType::Tagged();
   }
 
   DECLARE_CONCRETE_INSTRUCTION(ForInCacheArray);
 
  private:
   HForInCacheArray(HValue* enumerable,
                    HValue* keys,
                    int idx) : idx_(idx) {
     SetOperandAt(0, enumerable);
     SetOperandAt(1, keys);
     set_representation(Representation::Tagged());
   }
 
   int idx_;
   HForInCacheArray* index_cache_;
 };
 
 
-class HLoadFieldByIndex : public HTemplateInstruction<2> {
+class HLoadFieldByIndex V8_FINAL : public HTemplateInstruction<2> {
  public:
   HLoadFieldByIndex(HValue* object,
                     HValue* index) {
     SetOperandAt(0, object);
     SetOperandAt(1, index);
     set_representation(Representation::Tagged());
   }
 
-  virtual Representation RequiredInputRepresentation(int index) {
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     return Representation::Tagged();
   }
 
   HValue* object() { return OperandAt(0); }
   HValue* index() { return OperandAt(1); }
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
-  virtual HType CalculateInferredType() {
+  virtual HType CalculateInferredType() V8_OVERRIDE {
     return HType::Tagged();
   }
 
   DECLARE_CONCRETE_INSTRUCTION(LoadFieldByIndex);
 
  private:
-  virtual bool IsDeletable() const { return true; }
+  virtual bool IsDeletable() const V8_OVERRIDE { return true; }
 };
 
 
 #undef DECLARE_INSTRUCTION
 #undef DECLARE_CONCRETE_INSTRUCTION
 
 } }  // namespace v8::internal
 
 #endif  // V8_HYDROGEN_INSTRUCTIONS_H_