diff --git a/src/arm/lithium-arm.h b/src/arm/lithium-arm.h
index d81dc0f57c..9a6c3958c7 100644
--- a/src/arm/lithium-arm.h
+++ b/src/arm/lithium-arm.h
@@ -189,13 +189,17 @@ class LCodeGen;
   V(WrapReceiver)
 
 
-#define DECLARE_CONCRETE_INSTRUCTION(type, mnemonic)              \
-  virtual Opcode opcode() const { return LInstruction::k##type; } \
-  virtual void CompileToNative(LCodeGen* generator);              \
-  virtual const char* Mnemonic() const { return mnemonic; }       \
-  static L##type* cast(LInstruction* instr) {                     \
-    ASSERT(instr->Is##type());                                    \
-    return reinterpret_cast<L##type*>(instr);                     \
+#define DECLARE_CONCRETE_INSTRUCTION(type, mnemonic)                        \
+  virtual Opcode opcode() const V8_FINAL V8_OVERRIDE {                      \
+    return LInstruction::k##type;                                           \
+  }                                                                         \
+  virtual void CompileToNative(LCodeGen* generator) V8_FINAL V8_OVERRIDE;   \
+  virtual const char* Mnemonic() const V8_FINAL V8_OVERRIDE {               \
+    return mnemonic;                                                        \
+  }                                                                         \
+  static L##type* cast(LInstruction* instr) {                               \
+    ASSERT(instr->Is##type());                                              \
+    return reinterpret_cast<L##type*>(instr);                               \
   }
 
 
@@ -205,7 +209,7 @@ class LCodeGen;
   }
 
 
-class LInstruction: public ZoneObject {
+class LInstruction : public ZoneObject {
  public:
   LInstruction()
       : environment_(NULL),
@@ -214,7 +218,7 @@ class LInstruction: public ZoneObject {
     set_position(RelocInfo::kNoPosition);
   }
 
-  virtual ~LInstruction() { }
+  virtual ~LInstruction() {}
 
   virtual void CompileToNative(LCodeGen* generator) = 0;
   virtual const char* Mnemonic() const = 0;
@@ -313,11 +317,13 @@ class LInstruction: public ZoneObject {
 // I = number of input operands.
 // T = number of temporary operands.
 template<int R, int I, int T>
-class LTemplateInstruction: public LInstruction {
+class LTemplateInstruction : public LInstruction {
  public:
   // Allow 0 or 1 output operands.
   STATIC_ASSERT(R == 0 || R == 1);
-  virtual bool HasResult() const { return R != 0 && result() != NULL; }
+  virtual bool HasResult() const V8_FINAL V8_OVERRIDE {
+    return R != 0 && result() != NULL;
+  }
   void set_result(LOperand* operand) { results_[0] = operand; }
   LOperand* result() const { return results_[0]; }
 
@@ -327,15 +333,15 @@ class LTemplateInstruction: public LInstruction {
   EmbeddedContainer<LOperand*, T> temps_;
 
  private:
-  virtual int InputCount() { return I; }
-  virtual LOperand* InputAt(int i) { return inputs_[i]; }
+  virtual int InputCount() V8_FINAL V8_OVERRIDE { return I; }
+  virtual LOperand* InputAt(int i) V8_FINAL V8_OVERRIDE { return inputs_[i]; }
 
-  virtual int TempCount() { return T; }
-  virtual LOperand* TempAt(int i) { return temps_[i]; }
+  virtual int TempCount() V8_FINAL V8_OVERRIDE { return T; }
+  virtual LOperand* TempAt(int i) V8_FINAL V8_OVERRIDE { return temps_[i]; }
 };
 
 
-class LGap: public LTemplateInstruction<0, 0, 0> {
+class LGap : public LTemplateInstruction<0, 0, 0> {
  public:
   explicit LGap(HBasicBlock* block)
       : block_(block) {
@@ -346,8 +352,8 @@ class LGap: public LTemplateInstruction<0, 0, 0> {
   }
 
   // Can't use the DECLARE-macro here because of sub-classes.
-  virtual bool IsGap() const { return true; }
-  virtual void PrintDataTo(StringStream* stream);
+  virtual bool IsGap() const V8_OVERRIDE { return true; }
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
   static LGap* cast(LInstruction* instr) {
     ASSERT(instr->IsGap());
     return reinterpret_cast<LGap*>(instr);
@@ -383,11 +389,11 @@ class LGap: public LTemplateInstruction<0, 0, 0> {
 };
 
 
-class LInstructionGap: public LGap {
+class LInstructionGap V8_FINAL : public LGap {
  public:
   explicit LInstructionGap(HBasicBlock* block) : LGap(block) { }
 
-  virtual bool HasInterestingComment(LCodeGen* gen) const {
+  virtual bool HasInterestingComment(LCodeGen* gen) const V8_OVERRIDE {
     return !IsRedundant();
   }
 
@@ -395,14 +401,14 @@ class LInstructionGap: public LGap {
 };
 
 
-class LGoto: public LTemplateInstruction<0, 0, 0> {
+class LGoto V8_FINAL : public LTemplateInstruction<0, 0, 0> {
  public:
   explicit LGoto(int block_id) : block_id_(block_id) { }
 
-  virtual bool HasInterestingComment(LCodeGen* gen) const;
+  virtual bool HasInterestingComment(LCodeGen* gen) const V8_OVERRIDE;
   DECLARE_CONCRETE_INSTRUCTION(Goto, "goto")
-  virtual void PrintDataTo(StringStream* stream);
-  virtual bool IsControl() const { return true; }
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
+  virtual bool IsControl() const V8_OVERRIDE { return true; }
 
   int block_id() const { return block_id_; }
 
@@ -411,7 +417,7 @@ class LGoto: public LTemplateInstruction<0, 0, 0> {
 };
 
 
-class LLazyBailout: public LTemplateInstruction<0, 0, 0> {
+class LLazyBailout V8_FINAL : public LTemplateInstruction<0, 0, 0> {
  public:
   LLazyBailout() : gap_instructions_size_(0) { }
 
@@ -427,7 +433,7 @@ class LLazyBailout: public LTemplateInstruction<0, 0, 0> {
 };
 
 
-class LDummyUse: public LTemplateInstruction<1, 1, 0> {
+class LDummyUse V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LDummyUse(LOperand* value) {
     inputs_[0] = value;
@@ -436,22 +442,24 @@ class LDummyUse: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LDeoptimize: public LTemplateInstruction<0, 0, 0> {
+class LDeoptimize V8_FINAL : public LTemplateInstruction<0, 0, 0> {
  public:
   DECLARE_CONCRETE_INSTRUCTION(Deoptimize, "deoptimize")
   DECLARE_HYDROGEN_ACCESSOR(Deoptimize)
 };
 
 
-class LLabel: public LGap {
+class LLabel V8_FINAL : public LGap {
  public:
   explicit LLabel(HBasicBlock* block)
       : LGap(block), replacement_(NULL) { }
 
-  virtual bool HasInterestingComment(LCodeGen* gen) const { return false; }
+  virtual bool HasInterestingComment(LCodeGen* gen) const V8_OVERRIDE {
+    return false;
+  }
   DECLARE_CONCRETE_INSTRUCTION(Label, "label")
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
   int block_id() const { return block()->block_id(); }
   bool is_loop_header() const { return block()->IsLoopHeader(); }
@@ -467,14 +475,14 @@ class LLabel: public LGap {
 };
 
 
-class LParameter: public LTemplateInstruction<1, 0, 0> {
+class LParameter V8_FINAL : public LTemplateInstruction<1, 0, 0> {
  public:
   virtual bool HasInterestingComment(LCodeGen* gen) const { return false; }
   DECLARE_CONCRETE_INSTRUCTION(Parameter, "parameter")
 };
 
 
-class LCallStub: public LTemplateInstruction<1, 0, 0> {
+class LCallStub V8_FINAL : public LTemplateInstruction<1, 0, 0> {
  public:
   DECLARE_CONCRETE_INSTRUCTION(CallStub, "call-stub")
   DECLARE_HYDROGEN_ACCESSOR(CallStub)
@@ -485,19 +493,21 @@ class LCallStub: public LTemplateInstruction<1, 0, 0> {
 };
 
 
-class LUnknownOSRValue: public LTemplateInstruction<1, 0, 0> {
+class LUnknownOSRValue V8_FINAL : public LTemplateInstruction<1, 0, 0> {
  public:
-  virtual bool HasInterestingComment(LCodeGen* gen) const { return false; }
+  virtual bool HasInterestingComment(LCodeGen* gen) const V8_OVERRIDE {
+    return false;
+  }
   DECLARE_CONCRETE_INSTRUCTION(UnknownOSRValue, "unknown-osr-value")
 };
 
 
 template<int I, int T>
-class LControlInstruction: public LTemplateInstruction<0, I, T> {
+class LControlInstruction : public LTemplateInstruction<0, I, T> {
  public:
   LControlInstruction() : false_label_(NULL), true_label_(NULL) { }
 
-  virtual bool IsControl() const { return true; }
+  virtual bool IsControl() const V8_FINAL V8_OVERRIDE { return true; }
 
   int SuccessorCount() { return hydrogen()->SuccessorCount(); }
   HBasicBlock* SuccessorAt(int i) { return hydrogen()->SuccessorAt(i); }
@@ -536,7 +546,7 @@ class LControlInstruction: public LTemplateInstruction<0, I, T> {
 };
 
 
-class LWrapReceiver: public LTemplateInstruction<1, 2, 0> {
+class LWrapReceiver V8_FINAL : public LTemplateInstruction<1, 2, 0> {
  public:
   LWrapReceiver(LOperand* receiver, LOperand* function) {
     inputs_[0] = receiver;
@@ -550,7 +560,7 @@ class LWrapReceiver: public LTemplateInstruction<1, 2, 0> {
 };
 
 
-class LApplyArguments: public LTemplateInstruction<1, 4, 0> {
+class LApplyArguments V8_FINAL : public LTemplateInstruction<1, 4, 0> {
  public:
   LApplyArguments(LOperand* function,
                   LOperand* receiver,
@@ -571,7 +581,7 @@ class LApplyArguments: public LTemplateInstruction<1, 4, 0> {
 };
 
 
-class LAccessArgumentsAt: public LTemplateInstruction<1, 3, 0> {
+class LAccessArgumentsAt V8_FINAL : public LTemplateInstruction<1, 3, 0> {
  public:
   LAccessArgumentsAt(LOperand* arguments, LOperand* length, LOperand* index) {
     inputs_[0] = arguments;
@@ -585,11 +595,11 @@ class LAccessArgumentsAt: public LTemplateInstruction<1, 3, 0> {
   LOperand* length() { return inputs_[1]; }
   LOperand* index() { return inputs_[2]; }
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 };
 
 
-class LArgumentsLength: public LTemplateInstruction<1, 1, 0> {
+class LArgumentsLength V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LArgumentsLength(LOperand* elements) {
     inputs_[0] = elements;
@@ -601,14 +611,14 @@ class LArgumentsLength: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LArgumentsElements: public LTemplateInstruction<1, 0, 0> {
+class LArgumentsElements V8_FINAL : public LTemplateInstruction<1, 0, 0> {
  public:
   DECLARE_CONCRETE_INSTRUCTION(ArgumentsElements, "arguments-elements")
   DECLARE_HYDROGEN_ACCESSOR(ArgumentsElements)
 };
 
 
-class LModI: public LTemplateInstruction<1, 2, 2> {
+class LModI V8_FINAL : public LTemplateInstruction<1, 2, 2> {
  public:
   LModI(LOperand* left,
         LOperand* right,
@@ -630,7 +640,7 @@ class LModI: public LTemplateInstruction<1, 2, 2> {
 };
 
 
-class LDivI: public LTemplateInstruction<1, 2, 1> {
+class LDivI V8_FINAL : public LTemplateInstruction<1, 2, 1> {
  public:
   LDivI(LOperand* left, LOperand* right, LOperand* temp) {
     inputs_[0] = left;
@@ -647,7 +657,7 @@ class LDivI: public LTemplateInstruction<1, 2, 1> {
 };
 
 
-class LMathFloorOfDiv: public LTemplateInstruction<1, 2, 1> {
+class LMathFloorOfDiv V8_FINAL : public LTemplateInstruction<1, 2, 1> {
  public:
   LMathFloorOfDiv(LOperand* left,
                   LOperand* right,
@@ -666,7 +676,7 @@ class LMathFloorOfDiv: public LTemplateInstruction<1, 2, 1> {
 };
 
 
-class LMulI: public LTemplateInstruction<1, 2, 1> {
+class LMulI V8_FINAL : public LTemplateInstruction<1, 2, 1> {
  public:
   LMulI(LOperand* left, LOperand* right, LOperand* temp) {
     inputs_[0] = left;
@@ -684,7 +694,7 @@ class LMulI: public LTemplateInstruction<1, 2, 1> {
 
 
 // Instruction for computing multiplier * multiplicand + addend.
-class LMultiplyAddD: public LTemplateInstruction<1, 3, 0> {
+class LMultiplyAddD V8_FINAL : public LTemplateInstruction<1, 3, 0> {
  public:
   LMultiplyAddD(LOperand* addend, LOperand* multiplier,
                 LOperand* multiplicand) {
@@ -702,7 +712,7 @@ class LMultiplyAddD: public LTemplateInstruction<1, 3, 0> {
 
 
 // Instruction for computing minuend - multiplier * multiplicand.
-class LMultiplySubD: public LTemplateInstruction<1, 3, 0> {
+class LMultiplySubD V8_FINAL : public LTemplateInstruction<1, 3, 0> {
  public:
   LMultiplySubD(LOperand* minuend, LOperand* multiplier,
                 LOperand* multiplicand) {
@@ -719,13 +729,13 @@ class LMultiplySubD: public LTemplateInstruction<1, 3, 0> {
 };
 
 
-class LDebugBreak: public LTemplateInstruction<0, 0, 0> {
+class LDebugBreak V8_FINAL : public LTemplateInstruction<0, 0, 0> {
  public:
   DECLARE_CONCRETE_INSTRUCTION(DebugBreak, "break")
 };
 
 
-class LCompareNumericAndBranch: public LControlInstruction<2, 0> {
+class LCompareNumericAndBranch V8_FINAL : public LControlInstruction<2, 0> {
  public:
   LCompareNumericAndBranch(LOperand* left, LOperand* right) {
     inputs_[0] = left;
@@ -744,11 +754,11 @@ class LCompareNumericAndBranch: public LControlInstruction<2, 0> {
     return hydrogen()->representation().IsDouble();
   }
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 };
 
 
-class LMathFloor: public LTemplateInstruction<1, 1, 0> {
+class LMathFloor V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LMathFloor(LOperand* value) {
     inputs_[0] = value;
@@ -761,7 +771,7 @@ class LMathFloor: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LMathRound: public LTemplateInstruction<1, 1, 1> {
+class LMathRound V8_FINAL : public LTemplateInstruction<1, 1, 1> {
  public:
   LMathRound(LOperand* value, LOperand* temp) {
     inputs_[0] = value;
@@ -776,7 +786,7 @@ class LMathRound: public LTemplateInstruction<1, 1, 1> {
 };
 
 
-class LMathAbs: public LTemplateInstruction<1, 1, 0> {
+class LMathAbs V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LMathAbs(LOperand* value) {
     inputs_[0] = value;
@@ -789,7 +799,7 @@ class LMathAbs: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LMathLog: public LTemplateInstruction<1, 1, 0> {
+class LMathLog V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LMathLog(LOperand* value) {
     inputs_[0] = value;
@@ -801,7 +811,7 @@ class LMathLog: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LMathSin: public LTemplateInstruction<1, 1, 0> {
+class LMathSin V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LMathSin(LOperand* value) {
     inputs_[0] = value;
@@ -813,7 +823,7 @@ class LMathSin: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LMathCos: public LTemplateInstruction<1, 1, 0> {
+class LMathCos V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LMathCos(LOperand* value) {
     inputs_[0] = value;
@@ -825,7 +835,7 @@ class LMathCos: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LMathTan: public LTemplateInstruction<1, 1, 0> {
+class LMathTan V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LMathTan(LOperand* value) {
     inputs_[0] = value;
@@ -837,7 +847,7 @@ class LMathTan: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LMathExp: public LTemplateInstruction<1, 1, 3> {
+class LMathExp V8_FINAL : public LTemplateInstruction<1, 1, 3> {
  public:
   LMathExp(LOperand* value,
            LOperand* double_temp,
@@ -859,7 +869,7 @@ class LMathExp: public LTemplateInstruction<1, 1, 3> {
 };
 
 
-class LMathSqrt: public LTemplateInstruction<1, 1, 0> {
+class LMathSqrt V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LMathSqrt(LOperand* value) {
     inputs_[0] = value;
@@ -871,7 +881,7 @@ class LMathSqrt: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LMathPowHalf: public LTemplateInstruction<1, 1, 1> {
+class LMathPowHalf V8_FINAL : public LTemplateInstruction<1, 1, 1> {
  public:
   LMathPowHalf(LOperand* value, LOperand* temp) {
     inputs_[0] = value;
@@ -885,7 +895,7 @@ class LMathPowHalf: public LTemplateInstruction<1, 1, 1> {
 };
 
 
-class LCmpObjectEqAndBranch: public LControlInstruction<2, 0> {
+class LCmpObjectEqAndBranch V8_FINAL : public LControlInstruction<2, 0> {
  public:
   LCmpObjectEqAndBranch(LOperand* left, LOperand* right) {
     inputs_[0] = left;
@@ -900,7 +910,7 @@ class LCmpObjectEqAndBranch: public LControlInstruction<2, 0> {
 };
 
 
-class LCmpHoleAndBranch: public LControlInstruction<1, 0> {
+class LCmpHoleAndBranch V8_FINAL : public LControlInstruction<1, 0> {
  public:
   explicit LCmpHoleAndBranch(LOperand* object) {
     inputs_[0] = object;
@@ -913,7 +923,7 @@ class LCmpHoleAndBranch: public LControlInstruction<1, 0> {
 };
 
 
-class LIsObjectAndBranch: public LControlInstruction<1, 1> {
+class LIsObjectAndBranch V8_FINAL : public LControlInstruction<1, 1> {
  public:
   LIsObjectAndBranch(LOperand* value, LOperand* temp) {
     inputs_[0] = value;
@@ -926,11 +936,11 @@ class LIsObjectAndBranch: public LControlInstruction<1, 1> {
   DECLARE_CONCRETE_INSTRUCTION(IsObjectAndBranch, "is-object-and-branch")
   DECLARE_HYDROGEN_ACCESSOR(IsObjectAndBranch)
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 };
 
 
-class LIsNumberAndBranch: public LControlInstruction<1, 0> {
+class LIsNumberAndBranch V8_FINAL : public LControlInstruction<1, 0> {
  public:
   explicit LIsNumberAndBranch(LOperand* value) {
     inputs_[0] = value;
@@ -943,7 +953,7 @@ class LIsNumberAndBranch: public LControlInstruction<1, 0> {
 };
 
 
-class LIsStringAndBranch: public LControlInstruction<1, 1> {
+class LIsStringAndBranch V8_FINAL : public LControlInstruction<1, 1> {
  public:
   LIsStringAndBranch(LOperand* value, LOperand* temp) {
     inputs_[0] = value;
@@ -956,11 +966,11 @@ class LIsStringAndBranch: public LControlInstruction<1, 1> {
   DECLARE_CONCRETE_INSTRUCTION(IsStringAndBranch, "is-string-and-branch")
   DECLARE_HYDROGEN_ACCESSOR(IsStringAndBranch)
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 };
 
 
-class LIsSmiAndBranch: public LControlInstruction<1, 0> {
+class LIsSmiAndBranch V8_FINAL : public LControlInstruction<1, 0> {
  public:
   explicit LIsSmiAndBranch(LOperand* value) {
     inputs_[0] = value;
@@ -971,11 +981,11 @@ class LIsSmiAndBranch: public LControlInstruction<1, 0> {
   DECLARE_CONCRETE_INSTRUCTION(IsSmiAndBranch, "is-smi-and-branch")
   DECLARE_HYDROGEN_ACCESSOR(IsSmiAndBranch)
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 };
 
 
-class LIsUndetectableAndBranch: public LControlInstruction<1, 1> {
+class LIsUndetectableAndBranch V8_FINAL : public LControlInstruction<1, 1> {
  public:
   explicit LIsUndetectableAndBranch(LOperand* value, LOperand* temp) {
     inputs_[0] = value;
@@ -989,11 +999,11 @@ class LIsUndetectableAndBranch: public LControlInstruction<1, 1> {
                                "is-undetectable-and-branch")
   DECLARE_HYDROGEN_ACCESSOR(IsUndetectableAndBranch)
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 };
 
 
-class LStringCompareAndBranch: public LControlInstruction<2, 0> {
+class LStringCompareAndBranch V8_FINAL : public LControlInstruction<2, 0> {
  public:
   LStringCompareAndBranch(LOperand* left, LOperand* right) {
     inputs_[0] = left;
@@ -1009,11 +1019,11 @@ class LStringCompareAndBranch: public LControlInstruction<2, 0> {
 
   Token::Value op() const { return hydrogen()->token(); }
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 };
 
 
-class LHasInstanceTypeAndBranch: public LControlInstruction<1, 0> {
+class LHasInstanceTypeAndBranch V8_FINAL : public LControlInstruction<1, 0> {
  public:
   explicit LHasInstanceTypeAndBranch(LOperand* value) {
     inputs_[0] = value;
@@ -1025,11 +1035,11 @@ class LHasInstanceTypeAndBranch: public LControlInstruction<1, 0> {
                                "has-instance-type-and-branch")
   DECLARE_HYDROGEN_ACCESSOR(HasInstanceTypeAndBranch)
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 };
 
 
-class LGetCachedArrayIndex: public LTemplateInstruction<1, 1, 0> {
+class LGetCachedArrayIndex V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LGetCachedArrayIndex(LOperand* value) {
     inputs_[0] = value;
@@ -1042,7 +1052,8 @@ class LGetCachedArrayIndex: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LHasCachedArrayIndexAndBranch: public LControlInstruction<1, 0> {
+class LHasCachedArrayIndexAndBranch V8_FINAL
+    : public LControlInstruction<1, 0> {
  public:
   explicit LHasCachedArrayIndexAndBranch(LOperand* value) {
     inputs_[0] = value;
@@ -1054,11 +1065,11 @@ class LHasCachedArrayIndexAndBranch: public LControlInstruction<1, 0> {
                                "has-cached-array-index-and-branch")
   DECLARE_HYDROGEN_ACCESSOR(HasCachedArrayIndexAndBranch)
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 };
 
 
-class LClassOfTestAndBranch: public LControlInstruction<1, 1> {
+class LClassOfTestAndBranch V8_FINAL : public LControlInstruction<1, 1> {
  public:
   LClassOfTestAndBranch(LOperand* value, LOperand* temp) {
     inputs_[0] = value;
@@ -1072,11 +1083,11 @@ class LClassOfTestAndBranch: public LControlInstruction<1, 1> {
                                "class-of-test-and-branch")
   DECLARE_HYDROGEN_ACCESSOR(ClassOfTestAndBranch)
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 };
 
 
-class LCmpT: public LTemplateInstruction<1, 2, 0> {
+class LCmpT V8_FINAL : public LTemplateInstruction<1, 2, 0> {
  public:
   LCmpT(LOperand* left, LOperand* right) {
     inputs_[0] = left;
@@ -1093,7 +1104,7 @@ class LCmpT: public LTemplateInstruction<1, 2, 0> {
 };
 
 
-class LInstanceOf: public LTemplateInstruction<1, 2, 0> {
+class LInstanceOf V8_FINAL : public LTemplateInstruction<1, 2, 0> {
  public:
   LInstanceOf(LOperand* left, LOperand* right) {
     inputs_[0] = left;
@@ -1107,7 +1118,7 @@ class LInstanceOf: public LTemplateInstruction<1, 2, 0> {
 };
 
 
-class LInstanceOfKnownGlobal: public LTemplateInstruction<1, 1, 1> {
+class LInstanceOfKnownGlobal V8_FINAL : public LTemplateInstruction<1, 1, 1> {
  public:
   LInstanceOfKnownGlobal(LOperand* value, LOperand* temp) {
     inputs_[0] = value;
@@ -1125,7 +1136,8 @@ class LInstanceOfKnownGlobal: public LTemplateInstruction<1, 1, 1> {
   LEnvironment* GetDeferredLazyDeoptimizationEnvironment() {
     return lazy_deopt_env_;
   }
-  virtual void SetDeferredLazyDeoptimizationEnvironment(LEnvironment* env) {
+  virtual void SetDeferredLazyDeoptimizationEnvironment(
+      LEnvironment* env) V8_OVERRIDE {
     lazy_deopt_env_ = env;
   }
 
@@ -1134,7 +1146,7 @@ class LInstanceOfKnownGlobal: public LTemplateInstruction<1, 1, 1> {
 };
 
 
-class LInstanceSize: public LTemplateInstruction<1, 1, 0> {
+class LInstanceSize V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LInstanceSize(LOperand* object) {
     inputs_[0] = object;
@@ -1147,7 +1159,7 @@ class LInstanceSize: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LBoundsCheck: public LTemplateInstruction<0, 2, 0> {
+class LBoundsCheck V8_FINAL : public LTemplateInstruction<0, 2, 0> {
  public:
   LBoundsCheck(LOperand* index, LOperand* length) {
     inputs_[0] = index;
@@ -1162,7 +1174,7 @@ class LBoundsCheck: public LTemplateInstruction<0, 2, 0> {
 };
 
 
-class LBitI: public LTemplateInstruction<1, 2, 0> {
+class LBitI V8_FINAL : public LTemplateInstruction<1, 2, 0> {
  public:
   LBitI(LOperand* left, LOperand* right) {
     inputs_[0] = left;
@@ -1179,7 +1191,7 @@ class LBitI: public LTemplateInstruction<1, 2, 0> {
 };
 
 
-class LShiftI: public LTemplateInstruction<1, 2, 0> {
+class LShiftI V8_FINAL : public LTemplateInstruction<1, 2, 0> {
  public:
   LShiftI(Token::Value op, LOperand* left, LOperand* right, bool can_deopt)
       : op_(op), can_deopt_(can_deopt) {
@@ -1200,7 +1212,7 @@ class LShiftI: public LTemplateInstruction<1, 2, 0> {
 };
 
 
-class LSubI: public LTemplateInstruction<1, 2, 0> {
+class LSubI V8_FINAL : public LTemplateInstruction<1, 2, 0> {
  public:
   LSubI(LOperand* left, LOperand* right) {
     inputs_[0] = left;
@@ -1215,7 +1227,7 @@ class LSubI: public LTemplateInstruction<1, 2, 0> {
 };
 
 
-class LRSubI: public LTemplateInstruction<1, 2, 0> {
+class LRSubI V8_FINAL : public LTemplateInstruction<1, 2, 0> {
  public:
   LRSubI(LOperand* left, LOperand* right) {
     inputs_[0] = left;
@@ -1230,7 +1242,7 @@ class LRSubI: public LTemplateInstruction<1, 2, 0> {
 };
 
 
-class LConstantI: public LTemplateInstruction<1, 0, 0> {
+class LConstantI V8_FINAL : public LTemplateInstruction<1, 0, 0> {
  public:
   DECLARE_CONCRETE_INSTRUCTION(ConstantI, "constant-i")
   DECLARE_HYDROGEN_ACCESSOR(Constant)
@@ -1239,7 +1251,7 @@ class LConstantI: public LTemplateInstruction<1, 0, 0> {
 };
 
 
-class LConstantS: public LTemplateInstruction<1, 0, 0> {
+class LConstantS V8_FINAL : public LTemplateInstruction<1, 0, 0> {
  public:
   DECLARE_CONCRETE_INSTRUCTION(ConstantS, "constant-s")
   DECLARE_HYDROGEN_ACCESSOR(Constant)
@@ -1248,7 +1260,7 @@ class LConstantS: public LTemplateInstruction<1, 0, 0> {
 };
 
 
-class LConstantD: public LTemplateInstruction<1, 0, 0> {
+class LConstantD V8_FINAL : public LTemplateInstruction<1, 0, 0> {
  public:
   DECLARE_CONCRETE_INSTRUCTION(ConstantD, "constant-d")
   DECLARE_HYDROGEN_ACCESSOR(Constant)
@@ -1257,7 +1269,7 @@ class LConstantD: public LTemplateInstruction<1, 0, 0> {
 };
 
 
-class LConstantE: public LTemplateInstruction<1, 0, 0> {
+class LConstantE V8_FINAL : public LTemplateInstruction<1, 0, 0> {
  public:
   DECLARE_CONCRETE_INSTRUCTION(ConstantE, "constant-e")
   DECLARE_HYDROGEN_ACCESSOR(Constant)
@@ -1268,7 +1280,7 @@ class LConstantE: public LTemplateInstruction<1, 0, 0> {
 };
 
 
-class LConstantT: public LTemplateInstruction<1, 0, 0> {
+class LConstantT V8_FINAL : public LTemplateInstruction<1, 0, 0> {
  public:
   DECLARE_CONCRETE_INSTRUCTION(ConstantT, "constant-t")
   DECLARE_HYDROGEN_ACCESSOR(Constant)
@@ -1277,7 +1289,7 @@ class LConstantT: public LTemplateInstruction<1, 0, 0> {
 };
 
 
-class LBranch: public LControlInstruction<1, 0> {
+class LBranch V8_FINAL : public LControlInstruction<1, 0> {
  public:
   explicit LBranch(LOperand* value) {
     inputs_[0] = value;
@@ -1288,11 +1300,11 @@ class LBranch: public LControlInstruction<1, 0> {
   DECLARE_CONCRETE_INSTRUCTION(Branch, "branch")
   DECLARE_HYDROGEN_ACCESSOR(Branch)
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 };
 
 
-class LCmpMapAndBranch: public LControlInstruction<1, 1> {
+class LCmpMapAndBranch V8_FINAL : public LControlInstruction<1, 1> {
  public:
   LCmpMapAndBranch(LOperand* value, LOperand* temp) {
     inputs_[0] = value;
@@ -1309,7 +1321,7 @@ class LCmpMapAndBranch: public LControlInstruction<1, 1> {
 };
 
 
-class LMapEnumLength: public LTemplateInstruction<1, 1, 0> {
+class LMapEnumLength V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LMapEnumLength(LOperand* value) {
     inputs_[0] = value;
@@ -1321,7 +1333,7 @@ class LMapEnumLength: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LElementsKind: public LTemplateInstruction<1, 1, 0> {
+class LElementsKind V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LElementsKind(LOperand* value) {
     inputs_[0] = value;
@@ -1334,7 +1346,7 @@ class LElementsKind: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LValueOf: public LTemplateInstruction<1, 1, 1> {
+class LValueOf V8_FINAL : public LTemplateInstruction<1, 1, 1> {
  public:
   LValueOf(LOperand* value, LOperand* temp) {
     inputs_[0] = value;
@@ -1349,7 +1361,7 @@ class LValueOf: public LTemplateInstruction<1, 1, 1> {
 };
 
 
-class LDateField: public LTemplateInstruction<1, 1, 1> {
+class LDateField V8_FINAL : public LTemplateInstruction<1, 1, 1> {
  public:
   LDateField(LOperand* date, LOperand* temp, Smi* index) : index_(index) {
     inputs_[0] = date;
@@ -1368,7 +1380,7 @@ class LDateField: public LTemplateInstruction<1, 1, 1> {
 };
 
 
-class LSeqStringSetChar: public LTemplateInstruction<1, 3, 0> {
+class LSeqStringSetChar V8_FINAL : public LTemplateInstruction<1, 3, 0> {
  public:
   LSeqStringSetChar(String::Encoding encoding,
                     LOperand* string,
@@ -1392,7 +1404,7 @@ class LSeqStringSetChar: public LTemplateInstruction<1, 3, 0> {
 };
 
 
-class LThrow: public LTemplateInstruction<0, 1, 0> {
+class LThrow V8_FINAL : public LTemplateInstruction<0, 1, 0> {
  public:
   explicit LThrow(LOperand* value) {
     inputs_[0] = value;
@@ -1404,7 +1416,7 @@ class LThrow: public LTemplateInstruction<0, 1, 0> {
 };
 
 
-class LAddI: public LTemplateInstruction<1, 2, 0> {
+class LAddI V8_FINAL : public LTemplateInstruction<1, 2, 0> {
  public:
   LAddI(LOperand* left, LOperand* right) {
     inputs_[0] = left;
@@ -1419,7 +1431,7 @@ class LAddI: public LTemplateInstruction<1, 2, 0> {
 };
 
 
-class LMathMinMax: public LTemplateInstruction<1, 2, 0> {
+class LMathMinMax V8_FINAL : public LTemplateInstruction<1, 2, 0> {
  public:
   LMathMinMax(LOperand* left, LOperand* right) {
     inputs_[0] = left;
@@ -1434,7 +1446,7 @@ class LMathMinMax: public LTemplateInstruction<1, 2, 0> {
 };
 
 
-class LPower: public LTemplateInstruction<1, 2, 0> {
+class LPower V8_FINAL : public LTemplateInstruction<1, 2, 0> {
  public:
   LPower(LOperand* left, LOperand* right) {
     inputs_[0] = left;
@@ -1449,7 +1461,7 @@ class LPower: public LTemplateInstruction<1, 2, 0> {
 };
 
 
-class LRandom: public LTemplateInstruction<1, 1, 0> {
+class LRandom V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LRandom(LOperand* global_object) {
     inputs_[0] = global_object;
@@ -1462,7 +1474,7 @@ class LRandom: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LArithmeticD: public LTemplateInstruction<1, 2, 0> {
+class LArithmeticD V8_FINAL : public LTemplateInstruction<1, 2, 0> {
  public:
   LArithmeticD(Token::Value op, LOperand* left, LOperand* right)
       : op_(op) {
@@ -1474,16 +1486,18 @@ class LArithmeticD: public LTemplateInstruction<1, 2, 0> {
   LOperand* left() { return inputs_[0]; }
   LOperand* right() { return inputs_[1]; }
 
-  virtual Opcode opcode() const { return LInstruction::kArithmeticD; }
-  virtual void CompileToNative(LCodeGen* generator);
-  virtual const char* Mnemonic() const;
+  virtual Opcode opcode() const V8_OVERRIDE {
+    return LInstruction::kArithmeticD;
+  }
+  virtual void CompileToNative(LCodeGen* generator) V8_OVERRIDE;
+  virtual const char* Mnemonic() const V8_OVERRIDE;
 
  private:
   Token::Value op_;
 };
 
 
-class LArithmeticT: public LTemplateInstruction<1, 2, 0> {
+class LArithmeticT V8_FINAL : public LTemplateInstruction<1, 2, 0> {
  public:
   LArithmeticT(Token::Value op, LOperand* left, LOperand* right)
       : op_(op) {
@@ -1495,16 +1509,18 @@ class LArithmeticT: public LTemplateInstruction<1, 2, 0> {
   LOperand* right() { return inputs_[1]; }
   Token::Value op() const { return op_; }
 
-  virtual Opcode opcode() const { return LInstruction::kArithmeticT; }
-  virtual void CompileToNative(LCodeGen* generator);
-  virtual const char* Mnemonic() const;
+  virtual Opcode opcode() const V8_OVERRIDE {
+    return LInstruction::kArithmeticT;
+  }
+  virtual void CompileToNative(LCodeGen* generator) V8_OVERRIDE;
+  virtual const char* Mnemonic() const V8_OVERRIDE;
 
  private:
   Token::Value op_;
 };
 
 
-class LReturn: public LTemplateInstruction<0, 2, 0> {
+class LReturn V8_FINAL : public LTemplateInstruction<0, 2, 0> {
  public:
   explicit LReturn(LOperand* value, LOperand* parameter_count) {
     inputs_[0] = value;
@@ -1526,7 +1542,7 @@ class LReturn: public LTemplateInstruction<0, 2, 0> {
 };
 
 
-class LLoadNamedField: public LTemplateInstruction<1, 1, 0> {
+class LLoadNamedField V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LLoadNamedField(LOperand* object) {
     inputs_[0] = object;
@@ -1539,7 +1555,7 @@ class LLoadNamedField: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LLoadNamedGeneric: public LTemplateInstruction<1, 1, 0> {
+class LLoadNamedGeneric V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LLoadNamedGeneric(LOperand* object) {
     inputs_[0] = object;
@@ -1554,7 +1570,7 @@ class LLoadNamedGeneric: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LLoadFunctionPrototype: public LTemplateInstruction<1, 1, 0> {
+class LLoadFunctionPrototype V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LLoadFunctionPrototype(LOperand* function) {
     inputs_[0] = function;
@@ -1567,7 +1583,8 @@ class LLoadFunctionPrototype: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LLoadExternalArrayPointer: public LTemplateInstruction<1, 1, 0> {
+class LLoadExternalArrayPointer V8_FINAL
+    : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LLoadExternalArrayPointer(LOperand* object) {
     inputs_[0] = object;
@@ -1580,7 +1597,7 @@ class LLoadExternalArrayPointer: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LLoadKeyed: public LTemplateInstruction<1, 2, 0> {
+class LLoadKeyed V8_FINAL : public LTemplateInstruction<1, 2, 0> {
  public:
   LLoadKeyed(LOperand* elements, LOperand* key) {
     inputs_[0] = elements;
@@ -1599,12 +1616,12 @@ class LLoadKeyed: public LTemplateInstruction<1, 2, 0> {
   DECLARE_CONCRETE_INSTRUCTION(LoadKeyed, "load-keyed")
   DECLARE_HYDROGEN_ACCESSOR(LoadKeyed)
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
   uint32_t additional_index() const { return hydrogen()->index_offset(); }
 };
 
 
-class LLoadKeyedGeneric: public LTemplateInstruction<1, 2, 0> {
+class LLoadKeyedGeneric V8_FINAL : public LTemplateInstruction<1, 2, 0> {
  public:
   LLoadKeyedGeneric(LOperand* object, LOperand* key) {
     inputs_[0] = object;
@@ -1618,14 +1635,14 @@ class LLoadKeyedGeneric: public LTemplateInstruction<1, 2, 0> {
 };
 
 
-class LLoadGlobalCell: public LTemplateInstruction<1, 0, 0> {
+class LLoadGlobalCell V8_FINAL : public LTemplateInstruction<1, 0, 0> {
  public:
   DECLARE_CONCRETE_INSTRUCTION(LoadGlobalCell, "load-global-cell")
   DECLARE_HYDROGEN_ACCESSOR(LoadGlobalCell)
 };
 
 
-class LLoadGlobalGeneric: public LTemplateInstruction<1, 1, 0> {
+class LLoadGlobalGeneric V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LLoadGlobalGeneric(LOperand* global_object) {
     inputs_[0] = global_object;
@@ -1641,7 +1658,7 @@ class LLoadGlobalGeneric: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LStoreGlobalCell: public LTemplateInstruction<0, 1, 1> {
+class LStoreGlobalCell V8_FINAL : public LTemplateInstruction<0, 1, 1> {
  public:
   LStoreGlobalCell(LOperand* value, LOperand* temp) {
     inputs_[0] = value;
@@ -1656,7 +1673,7 @@ class LStoreGlobalCell: public LTemplateInstruction<0, 1, 1> {
 };
 
 
-class LStoreGlobalGeneric: public LTemplateInstruction<0, 2, 0> {
+class LStoreGlobalGeneric V8_FINAL : public LTemplateInstruction<0, 2, 0> {
  public:
   explicit LStoreGlobalGeneric(LOperand* global_object,
                                LOperand* value) {
@@ -1675,7 +1692,7 @@ class LStoreGlobalGeneric: public LTemplateInstruction<0, 2, 0> {
 };
 
 
-class LLoadContextSlot: public LTemplateInstruction<1, 1, 0> {
+class LLoadContextSlot V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LLoadContextSlot(LOperand* context) {
     inputs_[0] = context;
@@ -1688,11 +1705,11 @@ class LLoadContextSlot: public LTemplateInstruction<1, 1, 0> {
 
   int slot_index() { return hydrogen()->slot_index(); }
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 };
 
 
-class LStoreContextSlot: public LTemplateInstruction<0, 2, 0> {
+class LStoreContextSlot V8_FINAL : public LTemplateInstruction<0, 2, 0> {
  public:
   LStoreContextSlot(LOperand* context, LOperand* value) {
     inputs_[0] = context;
@@ -1707,11 +1724,11 @@ class LStoreContextSlot: public LTemplateInstruction<0, 2, 0> {
 
   int slot_index() { return hydrogen()->slot_index(); }
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 };
 
 
-class LPushArgument: public LTemplateInstruction<0, 1, 0> {
+class LPushArgument V8_FINAL : public LTemplateInstruction<0, 1, 0> {
  public:
   explicit LPushArgument(LOperand* value) {
     inputs_[0] = value;
@@ -1723,7 +1740,7 @@ class LPushArgument: public LTemplateInstruction<0, 1, 0> {
 };
 
 
-class LDrop: public LTemplateInstruction<0, 0, 0> {
+class LDrop V8_FINAL : public LTemplateInstruction<0, 0, 0> {
  public:
   explicit LDrop(int count) : count_(count) { }
 
@@ -1736,7 +1753,7 @@ class LDrop: public LTemplateInstruction<0, 0, 0> {
 };
 
 
-class LInnerAllocatedObject: public LTemplateInstruction<1, 1, 0> {
+class LInnerAllocatedObject V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LInnerAllocatedObject(LOperand* base_object) {
     inputs_[0] = base_object;
@@ -1745,28 +1762,28 @@ class LInnerAllocatedObject: public LTemplateInstruction<1, 1, 0> {
   LOperand* base_object() { return inputs_[0]; }
   int offset() { return hydrogen()->offset(); }
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
   DECLARE_CONCRETE_INSTRUCTION(InnerAllocatedObject, "sub-allocated-object")
   DECLARE_HYDROGEN_ACCESSOR(InnerAllocatedObject)
 };
 
 
-class LThisFunction: public LTemplateInstruction<1, 0, 0> {
+class LThisFunction V8_FINAL : public LTemplateInstruction<1, 0, 0> {
  public:
   DECLARE_CONCRETE_INSTRUCTION(ThisFunction, "this-function")
   DECLARE_HYDROGEN_ACCESSOR(ThisFunction)
 };
 
 
-class LContext: public LTemplateInstruction<1, 0, 0> {
+class LContext V8_FINAL : public LTemplateInstruction<1, 0, 0> {
  public:
   DECLARE_CONCRETE_INSTRUCTION(Context, "context")
   DECLARE_HYDROGEN_ACCESSOR(Context)
 };
 
 
-class LOuterContext: public LTemplateInstruction<1, 1, 0> {
+class LOuterContext V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LOuterContext(LOperand* context) {
     inputs_[0] = context;
@@ -1778,14 +1795,14 @@ class LOuterContext: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LDeclareGlobals: public LTemplateInstruction<0, 0, 0> {
+class LDeclareGlobals V8_FINAL : public LTemplateInstruction<0, 0, 0> {
  public:
   DECLARE_CONCRETE_INSTRUCTION(DeclareGlobals, "declare-globals")
   DECLARE_HYDROGEN_ACCESSOR(DeclareGlobals)
 };
 
 
-class LGlobalObject: public LTemplateInstruction<1, 1, 0> {
+class LGlobalObject V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LGlobalObject(LOperand* context) {
     inputs_[0] = context;
@@ -1797,7 +1814,7 @@ class LGlobalObject: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LGlobalReceiver: public LTemplateInstruction<1, 1, 0> {
+class LGlobalReceiver V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LGlobalReceiver(LOperand* global_object) {
     inputs_[0] = global_object;
@@ -1809,19 +1826,19 @@ class LGlobalReceiver: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LCallConstantFunction: public LTemplateInstruction<1, 0, 0> {
+class LCallConstantFunction V8_FINAL : public LTemplateInstruction<1, 0, 0> {
  public:
   DECLARE_CONCRETE_INSTRUCTION(CallConstantFunction, "call-constant-function")
   DECLARE_HYDROGEN_ACCESSOR(CallConstantFunction)
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
   Handle<JSFunction> function() { return hydrogen()->function(); }
   int arity() const { return hydrogen()->argument_count() - 1; }
 };
 
 
-class LInvokeFunction: public LTemplateInstruction<1, 1, 0> {
+class LInvokeFunction V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LInvokeFunction(LOperand* function) {
     inputs_[0] = function;
@@ -1832,13 +1849,13 @@ class LInvokeFunction: public LTemplateInstruction<1, 1, 0> {
   DECLARE_CONCRETE_INSTRUCTION(InvokeFunction, "invoke-function")
   DECLARE_HYDROGEN_ACCESSOR(InvokeFunction)
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
   int arity() const { return hydrogen()->argument_count() - 1; }
 };
 
 
-class LCallKeyed: public LTemplateInstruction<1, 1, 0> {
+class LCallKeyed V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LCallKeyed(LOperand* key) {
     inputs_[0] = key;
@@ -1849,26 +1866,26 @@ class LCallKeyed: public LTemplateInstruction<1, 1, 0> {
   DECLARE_CONCRETE_INSTRUCTION(CallKeyed, "call-keyed")
   DECLARE_HYDROGEN_ACCESSOR(CallKeyed)
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
   int arity() const { return hydrogen()->argument_count() - 1; }
 };
 
 
 
-class LCallNamed: public LTemplateInstruction<1, 0, 0> {
+class LCallNamed V8_FINAL : public LTemplateInstruction<1, 0, 0> {
  public:
   DECLARE_CONCRETE_INSTRUCTION(CallNamed, "call-named")
   DECLARE_HYDROGEN_ACCESSOR(CallNamed)
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
   Handle<String> name() const { return hydrogen()->name(); }
   int arity() const { return hydrogen()->argument_count() - 1; }
 };
 
 
-class LCallFunction: public LTemplateInstruction<1, 1, 0> {
+class LCallFunction V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LCallFunction(LOperand* function) {
     inputs_[0] = function;
@@ -1883,30 +1900,30 @@ class LCallFunction: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LCallGlobal: public LTemplateInstruction<1, 0, 0> {
+class LCallGlobal V8_FINAL : public LTemplateInstruction<1, 0, 0> {
  public:
   DECLARE_CONCRETE_INSTRUCTION(CallGlobal, "call-global")
   DECLARE_HYDROGEN_ACCESSOR(CallGlobal)
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
   Handle<String> name() const {return hydrogen()->name(); }
   int arity() const { return hydrogen()->argument_count() - 1; }
 };
 
 
-class LCallKnownGlobal: public LTemplateInstruction<1, 0, 0> {
+class LCallKnownGlobal V8_FINAL : public LTemplateInstruction<1, 0, 0> {
  public:
   DECLARE_CONCRETE_INSTRUCTION(CallKnownGlobal, "call-known-global")
   DECLARE_HYDROGEN_ACCESSOR(CallKnownGlobal)
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
   int arity() const { return hydrogen()->argument_count() - 1;  }
 };
 
 
-class LCallNew: public LTemplateInstruction<1, 1, 0> {
+class LCallNew V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LCallNew(LOperand* constructor) {
     inputs_[0] = constructor;
@@ -1917,13 +1934,13 @@ class LCallNew: public LTemplateInstruction<1, 1, 0> {
   DECLARE_CONCRETE_INSTRUCTION(CallNew, "call-new")
   DECLARE_HYDROGEN_ACCESSOR(CallNew)
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
   int arity() const { return hydrogen()->argument_count() - 1; }
 };
 
 
-class LCallNewArray: public LTemplateInstruction<1, 1, 0> {
+class LCallNewArray V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LCallNewArray(LOperand* constructor) {
     inputs_[0] = constructor;
@@ -1934,13 +1951,13 @@ class LCallNewArray: public LTemplateInstruction<1, 1, 0> {
   DECLARE_CONCRETE_INSTRUCTION(CallNewArray, "call-new-array")
   DECLARE_HYDROGEN_ACCESSOR(CallNewArray)
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
   int arity() const { return hydrogen()->argument_count() - 1; }
 };
 
 
-class LCallRuntime: public LTemplateInstruction<1, 0, 0> {
+class LCallRuntime V8_FINAL : public LTemplateInstruction<1, 0, 0> {
  public:
   DECLARE_CONCRETE_INSTRUCTION(CallRuntime, "call-runtime")
   DECLARE_HYDROGEN_ACCESSOR(CallRuntime)
@@ -1950,7 +1967,7 @@ class LCallRuntime: public LTemplateInstruction<1, 0, 0> {
 };
 
 
-class LInteger32ToDouble: public LTemplateInstruction<1, 1, 0> {
+class LInteger32ToDouble V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LInteger32ToDouble(LOperand* value) {
     inputs_[0] = value;
@@ -1962,7 +1979,7 @@ class LInteger32ToDouble: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LInteger32ToSmi: public LTemplateInstruction<1, 1, 0> {
+class LInteger32ToSmi V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LInteger32ToSmi(LOperand* value) {
     inputs_[0] = value;
@@ -1975,7 +1992,7 @@ class LInteger32ToSmi: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LUint32ToDouble: public LTemplateInstruction<1, 1, 0> {
+class LUint32ToDouble V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LUint32ToDouble(LOperand* value) {
     inputs_[0] = value;
@@ -1987,7 +2004,7 @@ class LUint32ToDouble: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LNumberTagI: public LTemplateInstruction<1, 1, 0> {
+class LNumberTagI V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LNumberTagI(LOperand* value) {
     inputs_[0] = value;
@@ -1999,7 +2016,7 @@ class LNumberTagI: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LNumberTagU: public LTemplateInstruction<1, 1, 0> {
+class LNumberTagU V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LNumberTagU(LOperand* value) {
     inputs_[0] = value;
@@ -2011,7 +2028,7 @@ class LNumberTagU: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LNumberTagD: public LTemplateInstruction<1, 1, 2> {
+class LNumberTagD V8_FINAL : public LTemplateInstruction<1, 1, 2> {
  public:
   LNumberTagD(LOperand* value, LOperand* temp, LOperand* temp2) {
     inputs_[0] = value;
@@ -2028,7 +2045,7 @@ class LNumberTagD: public LTemplateInstruction<1, 1, 2> {
 };
 
 
-class LDoubleToSmi: public LTemplateInstruction<1, 1, 2> {
+class LDoubleToSmi V8_FINAL : public LTemplateInstruction<1, 1, 2> {
  public:
   LDoubleToSmi(LOperand* value, LOperand* temp, LOperand* temp2) {
     inputs_[0] = value;
@@ -2048,7 +2065,7 @@ class LDoubleToSmi: public LTemplateInstruction<1, 1, 2> {
 
 
 // Sometimes truncating conversion from a tagged value to an int32.
-class LDoubleToI: public LTemplateInstruction<1, 1, 2> {
+class LDoubleToI V8_FINAL : public LTemplateInstruction<1, 1, 2> {
  public:
   LDoubleToI(LOperand* value, LOperand* temp, LOperand* temp2) {
     inputs_[0] = value;
@@ -2068,7 +2085,7 @@ class LDoubleToI: public LTemplateInstruction<1, 1, 2> {
 
 
 // Truncating conversion from a tagged value to an int32.
-class LTaggedToI: public LTemplateInstruction<1, 1, 3> {
+class LTaggedToI V8_FINAL : public LTemplateInstruction<1, 1, 3> {
  public:
   LTaggedToI(LOperand* value,
              LOperand* temp,
@@ -2092,7 +2109,7 @@ class LTaggedToI: public LTemplateInstruction<1, 1, 3> {
 };
 
 
-class LSmiTag: public LTemplateInstruction<1, 1, 0> {
+class LSmiTag V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LSmiTag(LOperand* value) {
     inputs_[0] = value;
@@ -2104,7 +2121,7 @@ class LSmiTag: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LNumberUntagD: public LTemplateInstruction<1, 1, 0> {
+class LNumberUntagD V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LNumberUntagD(LOperand* value) {
     inputs_[0] = value;
@@ -2117,7 +2134,7 @@ class LNumberUntagD: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LSmiUntag: public LTemplateInstruction<1, 1, 0> {
+class LSmiUntag V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   LSmiUntag(LOperand* value, bool needs_check)
       : needs_check_(needs_check) {
@@ -2134,7 +2151,7 @@ class LSmiUntag: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LStoreNamedField: public LTemplateInstruction<0, 2, 1> {
+class LStoreNamedField V8_FINAL : public LTemplateInstruction<0, 2, 1> {
  public:
   LStoreNamedField(LOperand* object, LOperand* value, LOperand* temp) {
     inputs_[0] = object;
@@ -2149,7 +2166,7 @@ class LStoreNamedField: public LTemplateInstruction<0, 2, 1> {
   DECLARE_CONCRETE_INSTRUCTION(StoreNamedField, "store-named-field")
   DECLARE_HYDROGEN_ACCESSOR(StoreNamedField)
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
   Handle<Map> transition() const { return hydrogen()->transition_map(); }
   Representation representation() const {
@@ -2158,7 +2175,7 @@ class LStoreNamedField: public LTemplateInstruction<0, 2, 1> {
 };
 
 
-class LStoreNamedGeneric: public LTemplateInstruction<0, 2, 0> {
+class LStoreNamedGeneric V8_FINAL : public LTemplateInstruction<0, 2, 0> {
  public:
   LStoreNamedGeneric(LOperand* object, LOperand* value) {
     inputs_[0] = object;
@@ -2171,14 +2188,14 @@ class LStoreNamedGeneric: public LTemplateInstruction<0, 2, 0> {
   DECLARE_CONCRETE_INSTRUCTION(StoreNamedGeneric, "store-named-generic")
   DECLARE_HYDROGEN_ACCESSOR(StoreNamedGeneric)
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
   Handle<Object> name() const { return hydrogen()->name(); }
   StrictModeFlag strict_mode_flag() { return hydrogen()->strict_mode_flag(); }
 };
 
 
-class LStoreKeyed: public LTemplateInstruction<0, 3, 0> {
+class LStoreKeyed V8_FINAL : public LTemplateInstruction<0, 3, 0> {
  public:
   LStoreKeyed(LOperand* object, LOperand* key, LOperand* value) {
     inputs_[0] = object;
@@ -2197,7 +2214,7 @@ class LStoreKeyed: public LTemplateInstruction<0, 3, 0> {
   DECLARE_CONCRETE_INSTRUCTION(StoreKeyed, "store-keyed")
   DECLARE_HYDROGEN_ACCESSOR(StoreKeyed)
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
   bool NeedsCanonicalization() {
     if (hydrogen()->value()->IsAdd() || hydrogen()->value()->IsSub() ||
         hydrogen()->value()->IsMul() || hydrogen()->value()->IsDiv()) {
@@ -2209,7 +2226,7 @@ class LStoreKeyed: public LTemplateInstruction<0, 3, 0> {
 };
 
 
-class LStoreKeyedGeneric: public LTemplateInstruction<0, 3, 0> {
+class LStoreKeyedGeneric V8_FINAL : public LTemplateInstruction<0, 3, 0> {
  public:
   LStoreKeyedGeneric(LOperand* obj, LOperand* key, LOperand* value) {
     inputs_[0] = obj;
@@ -2224,13 +2241,13 @@ class LStoreKeyedGeneric: public LTemplateInstruction<0, 3, 0> {
   DECLARE_CONCRETE_INSTRUCTION(StoreKeyedGeneric, "store-keyed-generic")
   DECLARE_HYDROGEN_ACCESSOR(StoreKeyedGeneric)
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
   StrictModeFlag strict_mode_flag() { return hydrogen()->strict_mode_flag(); }
 };
 
 
-class LTransitionElementsKind: public LTemplateInstruction<0, 1, 1> {
+class LTransitionElementsKind V8_FINAL : public LTemplateInstruction<0, 1, 1> {
  public:
   LTransitionElementsKind(LOperand* object,
                           LOperand* new_map_temp) {
@@ -2245,7 +2262,7 @@ class LTransitionElementsKind: public LTemplateInstruction<0, 1, 1> {
                                "transition-elements-kind")
   DECLARE_HYDROGEN_ACCESSOR(TransitionElementsKind)
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
   Handle<Map> original_map() { return hydrogen()->original_map(); }
   Handle<Map> transitioned_map() { return hydrogen()->transitioned_map(); }
@@ -2254,7 +2271,7 @@ class LTransitionElementsKind: public LTemplateInstruction<0, 1, 1> {
 };
 
 
-class LTrapAllocationMemento : public LTemplateInstruction<0, 1, 1> {
+class LTrapAllocationMemento V8_FINAL : public LTemplateInstruction<0, 1, 1> {
  public:
   LTrapAllocationMemento(LOperand* object,
                          LOperand* temp) {
@@ -2270,7 +2287,7 @@ class LTrapAllocationMemento : public LTemplateInstruction<0, 1, 1> {
 };
 
 
-class LStringAdd: public LTemplateInstruction<1, 2, 0> {
+class LStringAdd V8_FINAL : public LTemplateInstruction<1, 2, 0> {
  public:
   LStringAdd(LOperand* left, LOperand* right) {
     inputs_[0] = left;
@@ -2286,7 +2303,7 @@ class LStringAdd: public LTemplateInstruction<1, 2, 0> {
 
 
 
-class LStringCharCodeAt: public LTemplateInstruction<1, 2, 0> {
+class LStringCharCodeAt V8_FINAL : public LTemplateInstruction<1, 2, 0> {
  public:
   LStringCharCodeAt(LOperand* string, LOperand* index) {
     inputs_[0] = string;
@@ -2301,7 +2318,7 @@ class LStringCharCodeAt: public LTemplateInstruction<1, 2, 0> {
 };
 
 
-class LStringCharFromCode: public LTemplateInstruction<1, 1, 0> {
+class LStringCharFromCode V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LStringCharFromCode(LOperand* char_code) {
     inputs_[0] = char_code;
@@ -2314,7 +2331,7 @@ class LStringCharFromCode: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LCheckFunction: public LTemplateInstruction<0, 1, 0> {
+class LCheckFunction V8_FINAL : public LTemplateInstruction<0, 1, 0> {
  public:
   explicit LCheckFunction(LOperand* value) {
     inputs_[0] = value;
@@ -2327,7 +2344,7 @@ class LCheckFunction: public LTemplateInstruction<0, 1, 0> {
 };
 
 
-class LCheckInstanceType: public LTemplateInstruction<0, 1, 0> {
+class LCheckInstanceType V8_FINAL : public LTemplateInstruction<0, 1, 0> {
  public:
   explicit LCheckInstanceType(LOperand* value) {
     inputs_[0] = value;
@@ -2340,7 +2357,7 @@ class LCheckInstanceType: public LTemplateInstruction<0, 1, 0> {
 };
 
 
-class LCheckMaps: public LTemplateInstruction<0, 1, 0> {
+class LCheckMaps V8_FINAL : public LTemplateInstruction<0, 1, 0> {
  public:
   explicit LCheckMaps(LOperand* value) {
     inputs_[0] = value;
@@ -2353,7 +2370,7 @@ class LCheckMaps: public LTemplateInstruction<0, 1, 0> {
 };
 
 
-class LCheckSmi: public LTemplateInstruction<1, 1, 0> {
+class LCheckSmi V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LCheckSmi(LOperand* value) {
     inputs_[0] = value;
@@ -2365,7 +2382,7 @@ class LCheckSmi: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LCheckNonSmi: public LTemplateInstruction<0, 1, 0> {
+class LCheckNonSmi V8_FINAL : public LTemplateInstruction<0, 1, 0> {
  public:
   explicit LCheckNonSmi(LOperand* value) {
     inputs_[0] = value;
@@ -2378,7 +2395,7 @@ class LCheckNonSmi: public LTemplateInstruction<0, 1, 0> {
 };
 
 
-class LClampDToUint8: public LTemplateInstruction<1, 1, 0> {
+class LClampDToUint8 V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LClampDToUint8(LOperand* unclamped) {
     inputs_[0] = unclamped;
@@ -2390,7 +2407,7 @@ class LClampDToUint8: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LClampIToUint8: public LTemplateInstruction<1, 1, 0> {
+class LClampIToUint8 V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LClampIToUint8(LOperand* unclamped) {
     inputs_[0] = unclamped;
@@ -2402,7 +2419,7 @@ class LClampIToUint8: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LClampTToUint8: public LTemplateInstruction<1, 1, 1> {
+class LClampTToUint8 V8_FINAL : public LTemplateInstruction<1, 1, 1> {
  public:
   LClampTToUint8(LOperand* unclamped, LOperand* temp) {
     inputs_[0] = unclamped;
@@ -2416,7 +2433,7 @@ class LClampTToUint8: public LTemplateInstruction<1, 1, 1> {
 };
 
 
-class LAllocate: public LTemplateInstruction<1, 2, 2> {
+class LAllocate V8_FINAL : public LTemplateInstruction<1, 2, 2> {
  public:
   LAllocate(LOperand* size, LOperand* temp1, LOperand* temp2) {
     inputs_[1] = size;
@@ -2433,21 +2450,21 @@ class LAllocate: public LTemplateInstruction<1, 2, 2> {
 };
 
 
-class LRegExpLiteral: public LTemplateInstruction<1, 0, 0> {
+class LRegExpLiteral V8_FINAL : public LTemplateInstruction<1, 0, 0> {
  public:
   DECLARE_CONCRETE_INSTRUCTION(RegExpLiteral, "regexp-literal")
   DECLARE_HYDROGEN_ACCESSOR(RegExpLiteral)
 };
 
 
-class LFunctionLiteral: public LTemplateInstruction<1, 0, 0> {
+class LFunctionLiteral V8_FINAL : public LTemplateInstruction<1, 0, 0> {
  public:
   DECLARE_CONCRETE_INSTRUCTION(FunctionLiteral, "function-literal")
   DECLARE_HYDROGEN_ACCESSOR(FunctionLiteral)
 };
 
 
-class LToFastProperties: public LTemplateInstruction<1, 1, 0> {
+class LToFastProperties V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LToFastProperties(LOperand* value) {
     inputs_[0] = value;
@@ -2460,7 +2477,7 @@ class LToFastProperties: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LTypeof: public LTemplateInstruction<1, 1, 0> {
+class LTypeof V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LTypeof(LOperand* value) {
     inputs_[0] = value;
@@ -2472,7 +2489,7 @@ class LTypeof: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LTypeofIsAndBranch: public LControlInstruction<1, 0> {
+class LTypeofIsAndBranch V8_FINAL : public LControlInstruction<1, 0> {
  public:
   explicit LTypeofIsAndBranch(LOperand* value) {
     inputs_[0] = value;
@@ -2485,11 +2502,11 @@ class LTypeofIsAndBranch: public LControlInstruction<1, 0> {
 
   Handle<String> type_literal() { return hydrogen()->type_literal(); }
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 };
 
 
-class LIsConstructCallAndBranch: public LControlInstruction<0, 1> {
+class LIsConstructCallAndBranch V8_FINAL : public LControlInstruction<0, 1> {
  public:
   explicit LIsConstructCallAndBranch(LOperand* temp) {
     temps_[0] = temp;
@@ -2502,16 +2519,18 @@ class LIsConstructCallAndBranch: public LControlInstruction<0, 1> {
 };
 
 
-class LOsrEntry: public LTemplateInstruction<0, 0, 0> {
+class LOsrEntry V8_FINAL : public LTemplateInstruction<0, 0, 0> {
  public:
   LOsrEntry() {}
 
-  virtual bool HasInterestingComment(LCodeGen* gen) const { return false; }
+  virtual bool HasInterestingComment(LCodeGen* gen) const V8_OVERRIDE {
+    return false;
+  }
   DECLARE_CONCRETE_INSTRUCTION(OsrEntry, "osr-entry")
 };
 
 
-class LStackCheck: public LTemplateInstruction<0, 0, 0> {
+class LStackCheck V8_FINAL : public LTemplateInstruction<0, 0, 0> {
  public:
   DECLARE_CONCRETE_INSTRUCTION(StackCheck, "stack-check")
   DECLARE_HYDROGEN_ACCESSOR(StackCheck)
@@ -2523,7 +2542,7 @@ class LStackCheck: public LTemplateInstruction<0, 0, 0> {
 };
 
 
-class LForInPrepareMap: public LTemplateInstruction<1, 1, 0> {
+class LForInPrepareMap V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LForInPrepareMap(LOperand* object) {
     inputs_[0] = object;
@@ -2535,7 +2554,7 @@ class LForInPrepareMap: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LForInCacheArray: public LTemplateInstruction<1, 1, 0> {
+class LForInCacheArray V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LForInCacheArray(LOperand* map) {
     inputs_[0] = map;
@@ -2551,7 +2570,7 @@ class LForInCacheArray: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LCheckMapValue: public LTemplateInstruction<0, 2, 0> {
+class LCheckMapValue V8_FINAL : public LTemplateInstruction<0, 2, 0> {
  public:
   LCheckMapValue(LOperand* value, LOperand* map) {
     inputs_[0] = value;
@@ -2565,7 +2584,7 @@ class LCheckMapValue: public LTemplateInstruction<0, 2, 0> {
 };
 
 
-class LLoadFieldByIndex: public LTemplateInstruction<1, 2, 0> {
+class LLoadFieldByIndex V8_FINAL : public LTemplateInstruction<1, 2, 0> {
  public:
   LLoadFieldByIndex(LOperand* object, LOperand* index) {
     inputs_[0] = object;
@@ -2580,7 +2599,7 @@ class LLoadFieldByIndex: public LTemplateInstruction<1, 2, 0> {
 
 
 class LChunkBuilder;
-class LPlatformChunk: public LChunk {
+class LPlatformChunk V8_FINAL : public LChunk {
  public:
   LPlatformChunk(CompilationInfo* info, HGraph* graph)
       : LChunk(info, graph) { }
@@ -2590,7 +2609,7 @@ class LPlatformChunk: public LChunk {
 };
 
 
-class LChunkBuilder BASE_EMBEDDED {
+class LChunkBuilder V8_FINAL BASE_EMBEDDED {
  public:
   LChunkBuilder(CompilationInfo* info, HGraph* graph, LAllocator* allocator)
       : chunk_(NULL),
diff --git a/src/arm/lithium-codegen-arm.cc b/src/arm/lithium-codegen-arm.cc
index 9ec80f819a..8d9efbf31e 100644
--- a/src/arm/lithium-codegen-arm.cc
+++ b/src/arm/lithium-codegen-arm.cc
@@ -36,7 +36,7 @@ namespace v8 {
 namespace internal {
 
 
-class SafepointGenerator : public CallWrapper {
+class SafepointGenerator V8_FINAL : public CallWrapper {
  public:
   SafepointGenerator(LCodeGen* codegen,
                      LPointerMap* pointers,
@@ -44,11 +44,11 @@ class SafepointGenerator : public CallWrapper {
       : codegen_(codegen),
         pointers_(pointers),
         deopt_mode_(mode) { }
-  virtual ~SafepointGenerator() { }
+  virtual ~SafepointGenerator() {}
 
-  virtual void BeforeCall(int call_size) const { }
+  virtual void BeforeCall(int call_size) const V8_OVERRIDE {}
 
-  virtual void AfterCall() const {
+  virtual void AfterCall() const V8_OVERRIDE {
     codegen_->RecordSafepoint(pointers_, deopt_mode_);
   }
 
@@ -2734,15 +2734,15 @@ void LCodeGen::DoInstanceOf(LInstanceOf* instr) {
 
 
 void LCodeGen::DoInstanceOfKnownGlobal(LInstanceOfKnownGlobal* instr) {
-  class DeferredInstanceOfKnownGlobal: public LDeferredCode {
+  class DeferredInstanceOfKnownGlobal V8_FINAL : public LDeferredCode {
    public:
     DeferredInstanceOfKnownGlobal(LCodeGen* codegen,
                                   LInstanceOfKnownGlobal* instr)
         : LDeferredCode(codegen), instr_(instr) { }
-    virtual void Generate() {
+    virtual void Generate() V8_OVERRIDE {
       codegen()->DoDeferredInstanceOfKnownGlobal(instr_, &map_check_);
     }
-    virtual LInstruction* instr() { return instr_; }
+    virtual LInstruction* instr() V8_OVERRIDE { return instr_; }
     Label* map_check() { return &map_check_; }
    private:
     LInstanceOfKnownGlobal* instr_;
@@ -3721,14 +3721,14 @@ void LCodeGen::EmitIntegerMathAbs(LMathAbs* instr) {
 
 void LCodeGen::DoMathAbs(LMathAbs* instr) {
   // Class for deferred case.
-  class DeferredMathAbsTaggedHeapNumber: public LDeferredCode {
+  class DeferredMathAbsTaggedHeapNumber V8_FINAL : public LDeferredCode {
    public:
     DeferredMathAbsTaggedHeapNumber(LCodeGen* codegen, LMathAbs* instr)
         : LDeferredCode(codegen), instr_(instr) { }
-    virtual void Generate() {
+    virtual void Generate() V8_OVERRIDE {
       codegen()->DoDeferredMathAbsTaggedHeapNumber(instr_);
     }
-    virtual LInstruction* instr() { return instr_; }
+    virtual LInstruction* instr() V8_OVERRIDE { return instr_; }
    private:
     LMathAbs* instr_;
   };
@@ -3877,12 +3877,12 @@ void LCodeGen::DoPower(LPower* instr) {
 
 
 void LCodeGen::DoRandom(LRandom* instr) {
-  class DeferredDoRandom: public LDeferredCode {
+  class DeferredDoRandom V8_FINAL : public LDeferredCode {
    public:
     DeferredDoRandom(LCodeGen* codegen, LRandom* instr)
         : LDeferredCode(codegen), instr_(instr) { }
-    virtual void Generate() { codegen()->DoDeferredRandom(instr_); }
-    virtual LInstruction* instr() { return instr_; }
+    virtual void Generate() V8_OVERRIDE { codegen()->DoDeferredRandom(instr_); }
+    virtual LInstruction* instr() V8_OVERRIDE { return instr_; }
    private:
     LRandom* instr_;
   };
@@ -4519,12 +4519,14 @@ void LCodeGen::DoStringAdd(LStringAdd* instr) {
 
 
 void LCodeGen::DoStringCharCodeAt(LStringCharCodeAt* instr) {
-  class DeferredStringCharCodeAt: public LDeferredCode {
+  class DeferredStringCharCodeAt V8_FINAL : public LDeferredCode {
    public:
     DeferredStringCharCodeAt(LCodeGen* codegen, LStringCharCodeAt* instr)
         : LDeferredCode(codegen), instr_(instr) { }
-    virtual void Generate() { codegen()->DoDeferredStringCharCodeAt(instr_); }
-    virtual LInstruction* instr() { return instr_; }
+    virtual void Generate() V8_OVERRIDE {
+      codegen()->DoDeferredStringCharCodeAt(instr_);
+    }
+    virtual LInstruction* instr() V8_OVERRIDE { return instr_; }
    private:
     LStringCharCodeAt* instr_;
   };
@@ -4572,12 +4574,14 @@ void LCodeGen::DoDeferredStringCharCodeAt(LStringCharCodeAt* instr) {
 
 
 void LCodeGen::DoStringCharFromCode(LStringCharFromCode* instr) {
-  class DeferredStringCharFromCode: public LDeferredCode {
+  class DeferredStringCharFromCode V8_FINAL : public LDeferredCode {
    public:
     DeferredStringCharFromCode(LCodeGen* codegen, LStringCharFromCode* instr)
         : LDeferredCode(codegen), instr_(instr) { }
-    virtual void Generate() { codegen()->DoDeferredStringCharFromCode(instr_); }
-    virtual LInstruction* instr() { return instr_; }
+    virtual void Generate() V8_OVERRIDE {
+      codegen()->DoDeferredStringCharFromCode(instr_);
+    }
+    virtual LInstruction* instr() V8_OVERRIDE { return instr_; }
    private:
     LStringCharFromCode* instr_;
   };
@@ -4660,16 +4664,16 @@ void LCodeGen::DoUint32ToDouble(LUint32ToDouble* instr) {
 
 
 void LCodeGen::DoNumberTagI(LNumberTagI* instr) {
-  class DeferredNumberTagI: public LDeferredCode {
+  class DeferredNumberTagI V8_FINAL : public LDeferredCode {
    public:
     DeferredNumberTagI(LCodeGen* codegen, LNumberTagI* instr)
         : LDeferredCode(codegen), instr_(instr) { }
-    virtual void Generate() {
+    virtual void Generate() V8_OVERRIDE {
       codegen()->DoDeferredNumberTagI(instr_,
                                       instr_->value(),
                                       SIGNED_INT32);
     }
-    virtual LInstruction* instr() { return instr_; }
+    virtual LInstruction* instr() V8_OVERRIDE { return instr_; }
    private:
     LNumberTagI* instr_;
   };
@@ -4685,16 +4689,16 @@ void LCodeGen::DoNumberTagI(LNumberTagI* instr) {
 
 
 void LCodeGen::DoNumberTagU(LNumberTagU* instr) {
-  class DeferredNumberTagU: public LDeferredCode {
+  class DeferredNumberTagU V8_FINAL : public LDeferredCode {
    public:
     DeferredNumberTagU(LCodeGen* codegen, LNumberTagU* instr)
         : LDeferredCode(codegen), instr_(instr) { }
-    virtual void Generate() {
+    virtual void Generate() V8_OVERRIDE {
       codegen()->DoDeferredNumberTagI(instr_,
                                       instr_->value(),
                                       UNSIGNED_INT32);
     }
-    virtual LInstruction* instr() { return instr_; }
+    virtual LInstruction* instr() V8_OVERRIDE { return instr_; }
    private:
     LNumberTagU* instr_;
   };
@@ -4767,12 +4771,14 @@ void LCodeGen::DoDeferredNumberTagI(LInstruction* instr,
 
 
 void LCodeGen::DoNumberTagD(LNumberTagD* instr) {
-  class DeferredNumberTagD: public LDeferredCode {
+  class DeferredNumberTagD V8_FINAL : public LDeferredCode {
    public:
     DeferredNumberTagD(LCodeGen* codegen, LNumberTagD* instr)
         : LDeferredCode(codegen), instr_(instr) { }
-    virtual void Generate() { codegen()->DoDeferredNumberTagD(instr_); }
-    virtual LInstruction* instr() { return instr_; }
+    virtual void Generate() V8_OVERRIDE {
+      codegen()->DoDeferredNumberTagD(instr_);
+    }
+    virtual LInstruction* instr() V8_OVERRIDE { return instr_; }
    private:
     LNumberTagD* instr_;
   };
@@ -4965,12 +4971,14 @@ void LCodeGen::DoDeferredTaggedToI(LTaggedToI* instr) {
 
 
 void LCodeGen::DoTaggedToI(LTaggedToI* instr) {
-  class DeferredTaggedToI: public LDeferredCode {
+  class DeferredTaggedToI V8_FINAL : public LDeferredCode {
    public:
     DeferredTaggedToI(LCodeGen* codegen, LTaggedToI* instr)
         : LDeferredCode(codegen), instr_(instr) { }
-    virtual void Generate() { codegen()->DoDeferredTaggedToI(instr_); }
-    virtual LInstruction* instr() { return instr_; }
+    virtual void Generate() V8_OVERRIDE {
+      codegen()->DoDeferredTaggedToI(instr_);
+    }
+    virtual LInstruction* instr() V8_OVERRIDE { return instr_; }
    private:
     LTaggedToI* instr_;
   };
@@ -5161,17 +5169,17 @@ void LCodeGen::DoDeferredInstanceMigration(LCheckMaps* instr, Register object) {
 
 
 void LCodeGen::DoCheckMaps(LCheckMaps* instr) {
-  class DeferredCheckMaps: public LDeferredCode {
+  class DeferredCheckMaps V8_FINAL : public LDeferredCode {
    public:
     DeferredCheckMaps(LCodeGen* codegen, LCheckMaps* instr, Register object)
         : LDeferredCode(codegen), instr_(instr), object_(object) {
       SetExit(check_maps());
     }
-    virtual void Generate() {
+    virtual void Generate() V8_OVERRIDE {
       codegen()->DoDeferredInstanceMigration(instr_, object_);
     }
     Label* check_maps() { return &check_maps_; }
-    virtual LInstruction* instr() { return instr_; }
+    virtual LInstruction* instr() V8_OVERRIDE { return instr_; }
    private:
     LCheckMaps* instr_;
     Label check_maps_;
@@ -5264,12 +5272,14 @@ void LCodeGen::DoClampTToUint8(LClampTToUint8* instr) {
 
 
 void LCodeGen::DoAllocate(LAllocate* instr) {
-  class DeferredAllocate: public LDeferredCode {
+  class DeferredAllocate V8_FINAL : public LDeferredCode {
    public:
     DeferredAllocate(LCodeGen* codegen, LAllocate* instr)
         : LDeferredCode(codegen), instr_(instr) { }
-    virtual void Generate() { codegen()->DoDeferredAllocate(instr_); }
-    virtual LInstruction* instr() { return instr_; }
+    virtual void Generate() V8_OVERRIDE {
+      codegen()->DoDeferredAllocate(instr_);
+    }
+    virtual LInstruction* instr() V8_OVERRIDE { return instr_; }
    private:
     LAllocate* instr_;
   };
@@ -5620,12 +5630,14 @@ void LCodeGen::DoDeferredStackCheck(LStackCheck* instr) {
 
 
 void LCodeGen::DoStackCheck(LStackCheck* instr) {
-  class DeferredStackCheck: public LDeferredCode {
+  class DeferredStackCheck V8_FINAL : public LDeferredCode {
    public:
     DeferredStackCheck(LCodeGen* codegen, LStackCheck* instr)
         : LDeferredCode(codegen), instr_(instr) { }
-    virtual void Generate() { codegen()->DoDeferredStackCheck(instr_); }
-    virtual LInstruction* instr() { return instr_; }
+    virtual void Generate() V8_OVERRIDE {
+      codegen()->DoDeferredStackCheck(instr_);
+    }
+    virtual LInstruction* instr() V8_OVERRIDE { return instr_; }
    private:
     LStackCheck* instr_;
   };
diff --git a/src/arm/lithium-codegen-arm.h b/src/arm/lithium-codegen-arm.h
index d0bfcbbb94..8a0d3be69b 100644
--- a/src/arm/lithium-codegen-arm.h
+++ b/src/arm/lithium-codegen-arm.h
@@ -43,7 +43,7 @@ namespace internal {
 class LDeferredCode;
 class SafepointGenerator;
 
-class LCodeGen BASE_EMBEDDED {
+class LCodeGen V8_FINAL BASE_EMBEDDED {
  public:
   LCodeGen(LChunk* chunk, MacroAssembler* assembler, CompilationInfo* info)
       : zone_(info->zone()),
@@ -420,7 +420,7 @@ class LCodeGen BASE_EMBEDDED {
 
   int old_position_;
 
-  class PushSafepointRegistersScope BASE_EMBEDDED {
+  class PushSafepointRegistersScope V8_FINAL BASE_EMBEDDED {
    public:
     PushSafepointRegistersScope(LCodeGen* codegen,
                                 Safepoint::Kind kind)
@@ -468,7 +468,7 @@ class LCodeGen BASE_EMBEDDED {
 };
 
 
-class LDeferredCode: public ZoneObject {
+class LDeferredCode : public ZoneObject {
  public:
   explicit LDeferredCode(LCodeGen* codegen)
       : codegen_(codegen),
@@ -477,7 +477,7 @@ class LDeferredCode: public ZoneObject {
     codegen->AddDeferredCode(this);
   }
 
-  virtual ~LDeferredCode() { }
+  virtual ~LDeferredCode() {}
   virtual void Generate() = 0;
   virtual LInstruction* instr() = 0;
 
diff --git a/src/arm/lithium-gap-resolver-arm.h b/src/arm/lithium-gap-resolver-arm.h
index 9dd09c8d03..044c2864a4 100644
--- a/src/arm/lithium-gap-resolver-arm.h
+++ b/src/arm/lithium-gap-resolver-arm.h
@@ -38,7 +38,7 @@ namespace internal {
 class LCodeGen;
 class LGapResolver;
 
-class LGapResolver BASE_EMBEDDED {
+class LGapResolver V8_FINAL BASE_EMBEDDED {
  public:
   explicit LGapResolver(LCodeGen* owner);
 
diff --git a/src/ast.cc b/src/ast.cc
index 23b680d47f..8f69bd7059 100644
--- a/src/ast.cc
+++ b/src/ast.cc
@@ -858,12 +858,13 @@ bool RegExpCapture::IsAnchoredAtEnd() {
 // in as many cases as possible, to make it more difficult for incorrect
 // parses to look as correct ones which is likely if the input and
 // output formats are alike.
-class RegExpUnparser: public RegExpVisitor {
+class RegExpUnparser V8_FINAL : public RegExpVisitor {
  public:
   explicit RegExpUnparser(Zone* zone);
   void VisitCharacterRange(CharacterRange that);
   SmartArrayPointer<const char> ToString() { return stream_.ToCString(); }
-#define MAKE_CASE(Name) virtual void* Visit##Name(RegExp##Name*, void* data);
+#define MAKE_CASE(Name) virtual void* Visit##Name(RegExp##Name*,          \
+                                                  void* data) V8_OVERRIDE;
   FOR_EACH_REG_EXP_TREE_TYPE(MAKE_CASE)
 #undef MAKE_CASE
  private:
diff --git a/src/ast.h b/src/ast.h
index a8b74213ad..f61f495271 100644
--- a/src/ast.h
+++ b/src/ast.h
@@ -165,9 +165,11 @@ typedef ZoneList<Handle<String> > ZoneStringList;
 typedef ZoneList<Handle<Object> > ZoneObjectList;
 
 
-#define DECLARE_NODE_TYPE(type)                                             \
-  virtual void Accept(AstVisitor* v);                                       \
-  virtual AstNode::NodeType node_type() const { return AstNode::k##type; }  \
+#define DECLARE_NODE_TYPE(type)                                 \
+  virtual void Accept(AstVisitor* v) V8_OVERRIDE;                  \
+  virtual AstNode::NodeType node_type() const V8_FINAL V8_OVERRIDE {  \
+    return AstNode::k##type;                                    \
+  }                                                             \
   template<class> friend class AstNodeFactory;
 
 
@@ -180,7 +182,7 @@ enum AstPropertiesFlag {
 };
 
 
-class AstProperties BASE_EMBEDDED {
+class AstProperties V8_FINAL BASE_EMBEDDED {
  public:
   class Flags : public EnumSet<AstPropertiesFlag, int> {};
 
@@ -209,9 +211,9 @@ class AstNode: public ZoneObject {
     return zone->New(static_cast<int>(size));
   }
 
-  AstNode() { }
+  AstNode() {}
 
-  virtual ~AstNode() { }
+  virtual ~AstNode() {}
 
   virtual void Accept(AstVisitor* v) = 0;
   virtual NodeType node_type() const = 0;
@@ -254,7 +256,7 @@ class AstNode: public ZoneObject {
 };
 
 
-class Statement: public AstNode {
+class Statement : public AstNode {
  public:
   Statement() : statement_pos_(RelocInfo::kNoPosition) {}
 
@@ -269,7 +271,7 @@ class Statement: public AstNode {
 };
 
 
-class SmallMapList {
+class SmallMapList V8_FINAL {
  public:
   SmallMapList() {}
   SmallMapList(int capacity, Zone* zone) : list_(capacity, zone) {}
@@ -310,7 +312,7 @@ class SmallMapList {
 };
 
 
-class Expression: public AstNode {
+class Expression : public AstNode {
  public:
   enum Context {
     // Not assigned a context yet, or else will not be visited during
@@ -403,7 +405,7 @@ class Expression: public AstNode {
 };
 
 
-class BreakableStatement: public Statement {
+class BreakableStatement : public Statement {
  public:
   enum BreakableType {
     TARGET_FOR_ANONYMOUS,
@@ -415,7 +417,9 @@ class BreakableStatement: public Statement {
   ZoneStringList* labels() const { return labels_; }
 
   // Type testing & conversion.
-  virtual BreakableStatement* AsBreakableStatement() { return this; }
+  virtual BreakableStatement* AsBreakableStatement() V8_FINAL V8_OVERRIDE {
+    return this;
+  }
 
   // Code generation
   Label* break_target() { return &break_target_; }
@@ -448,7 +452,7 @@ class BreakableStatement: public Statement {
 };
 
 
-class Block: public BreakableStatement {
+class Block V8_FINAL : public BreakableStatement {
  public:
   DECLARE_NODE_TYPE(Block)
 
@@ -459,7 +463,7 @@ class Block: public BreakableStatement {
   ZoneList<Statement*>* statements() { return &statements_; }
   bool is_initializer_block() const { return is_initializer_block_; }
 
-  virtual bool IsJump() const {
+  virtual bool IsJump() const V8_OVERRIDE {
     return !statements_.is_empty() && statements_.last()->IsJump()
         && labels() == NULL;  // Good enough as an approximation...
   }
@@ -486,7 +490,7 @@ class Block: public BreakableStatement {
 };
 
 
-class Declaration: public AstNode {
+class Declaration : public AstNode {
  public:
   VariableProxy* proxy() const { return proxy_; }
   VariableMode mode() const { return mode_; }
@@ -513,11 +517,11 @@ class Declaration: public AstNode {
 };
 
 
-class VariableDeclaration: public Declaration {
+class VariableDeclaration V8_FINAL : public Declaration {
  public:
   DECLARE_NODE_TYPE(VariableDeclaration)
 
-  virtual InitializationFlag initialization() const {
+  virtual InitializationFlag initialization() const V8_OVERRIDE {
     return mode() == VAR ? kCreatedInitialized : kNeedsInitialization;
   }
 
@@ -530,15 +534,15 @@ class VariableDeclaration: public Declaration {
 };
 
 
-class FunctionDeclaration: public Declaration {
+class FunctionDeclaration V8_FINAL : public Declaration {
  public:
   DECLARE_NODE_TYPE(FunctionDeclaration)
 
   FunctionLiteral* fun() const { return fun_; }
-  virtual InitializationFlag initialization() const {
+  virtual InitializationFlag initialization() const V8_OVERRIDE {
     return kCreatedInitialized;
   }
-  virtual bool IsInlineable() const;
+  virtual bool IsInlineable() const V8_OVERRIDE;
 
  protected:
   FunctionDeclaration(VariableProxy* proxy,
@@ -557,12 +561,12 @@ class FunctionDeclaration: public Declaration {
 };
 
 
-class ModuleDeclaration: public Declaration {
+class ModuleDeclaration V8_FINAL : public Declaration {
  public:
   DECLARE_NODE_TYPE(ModuleDeclaration)
 
   Module* module() const { return module_; }
-  virtual InitializationFlag initialization() const {
+  virtual InitializationFlag initialization() const V8_OVERRIDE {
     return kCreatedInitialized;
   }
 
@@ -579,12 +583,12 @@ class ModuleDeclaration: public Declaration {
 };
 
 
-class ImportDeclaration: public Declaration {
+class ImportDeclaration V8_FINAL : public Declaration {
  public:
   DECLARE_NODE_TYPE(ImportDeclaration)
 
   Module* module() const { return module_; }
-  virtual InitializationFlag initialization() const {
+  virtual InitializationFlag initialization() const V8_OVERRIDE {
     return kCreatedInitialized;
   }
 
@@ -601,11 +605,11 @@ class ImportDeclaration: public Declaration {
 };
 
 
-class ExportDeclaration: public Declaration {
+class ExportDeclaration V8_FINAL : public Declaration {
  public:
   DECLARE_NODE_TYPE(ExportDeclaration)
 
-  virtual InitializationFlag initialization() const {
+  virtual InitializationFlag initialization() const V8_OVERRIDE {
     return kCreatedInitialized;
   }
 
@@ -615,7 +619,7 @@ class ExportDeclaration: public Declaration {
 };
 
 
-class Module: public AstNode {
+class Module : public AstNode {
  public:
   Interface* interface() const { return interface_; }
   Block* body() const { return body_; }
@@ -634,7 +638,7 @@ class Module: public AstNode {
 };
 
 
-class ModuleLiteral: public Module {
+class ModuleLiteral V8_FINAL : public Module {
  public:
   DECLARE_NODE_TYPE(ModuleLiteral)
 
@@ -643,7 +647,7 @@ class ModuleLiteral: public Module {
 };
 
 
-class ModuleVariable: public Module {
+class ModuleVariable V8_FINAL : public Module {
  public:
   DECLARE_NODE_TYPE(ModuleVariable)
 
@@ -657,7 +661,7 @@ class ModuleVariable: public Module {
 };
 
 
-class ModulePath: public Module {
+class ModulePath V8_FINAL : public Module {
  public:
   DECLARE_NODE_TYPE(ModulePath)
 
@@ -677,7 +681,7 @@ class ModulePath: public Module {
 };
 
 
-class ModuleUrl: public Module {
+class ModuleUrl V8_FINAL : public Module {
  public:
   DECLARE_NODE_TYPE(ModuleUrl)
 
@@ -693,7 +697,7 @@ class ModuleUrl: public Module {
 };
 
 
-class ModuleStatement: public Statement {
+class ModuleStatement V8_FINAL : public Statement {
  public:
   DECLARE_NODE_TYPE(ModuleStatement)
 
@@ -712,10 +716,12 @@ class ModuleStatement: public Statement {
 };
 
 
-class IterationStatement: public BreakableStatement {
+class IterationStatement : public BreakableStatement {
  public:
   // Type testing & conversion.
-  virtual IterationStatement* AsIterationStatement() { return this; }
+  virtual IterationStatement* AsIterationStatement() V8_FINAL V8_OVERRIDE {
+    return this;
+  }
 
   Statement* body() const { return body_; }
 
@@ -745,7 +751,7 @@ class IterationStatement: public BreakableStatement {
 };
 
 
-class DoWhileStatement: public IterationStatement {
+class DoWhileStatement V8_FINAL : public IterationStatement {
  public:
   DECLARE_NODE_TYPE(DoWhileStatement)
 
@@ -761,8 +767,8 @@ class DoWhileStatement: public IterationStatement {
   int condition_position() { return condition_position_; }
   void set_condition_position(int pos) { condition_position_ = pos; }
 
-  virtual BailoutId ContinueId() const { return continue_id_; }
-  virtual BailoutId StackCheckId() const { return back_edge_id_; }
+  virtual BailoutId ContinueId() const V8_OVERRIDE { return continue_id_; }
+  virtual BailoutId StackCheckId() const V8_OVERRIDE { return back_edge_id_; }
   BailoutId BackEdgeId() const { return back_edge_id_; }
 
  protected:
@@ -784,7 +790,7 @@ class DoWhileStatement: public IterationStatement {
 };
 
 
-class WhileStatement: public IterationStatement {
+class WhileStatement V8_FINAL : public IterationStatement {
  public:
   DECLARE_NODE_TYPE(WhileStatement)
 
@@ -801,8 +807,8 @@ class WhileStatement: public IterationStatement {
     may_have_function_literal_ = value;
   }
 
-  virtual BailoutId ContinueId() const { return EntryId(); }
-  virtual BailoutId StackCheckId() const { return body_id_; }
+  virtual BailoutId ContinueId() const V8_OVERRIDE { return EntryId(); }
+  virtual BailoutId StackCheckId() const V8_OVERRIDE { return body_id_; }
   BailoutId BodyId() const { return body_id_; }
 
  protected:
@@ -823,7 +829,7 @@ class WhileStatement: public IterationStatement {
 };
 
 
-class ForStatement: public IterationStatement {
+class ForStatement V8_FINAL : public IterationStatement {
  public:
   DECLARE_NODE_TYPE(ForStatement)
 
@@ -848,8 +854,8 @@ class ForStatement: public IterationStatement {
     may_have_function_literal_ = value;
   }
 
-  virtual BailoutId ContinueId() const { return continue_id_; }
-  virtual BailoutId StackCheckId() const { return body_id_; }
+  virtual BailoutId ContinueId() const V8_OVERRIDE { return continue_id_; }
+  virtual BailoutId StackCheckId() const V8_OVERRIDE { return body_id_; }
   BailoutId BodyId() const { return body_id_; }
 
   bool is_fast_smi_loop() { return loop_variable_ != NULL; }
@@ -882,7 +888,7 @@ class ForStatement: public IterationStatement {
 };
 
 
-class ForEachStatement: public IterationStatement {
+class ForEachStatement : public IterationStatement {
  public:
   enum VisitMode {
     ENUMERATE,   // for (each in subject) body;
@@ -911,7 +917,7 @@ class ForEachStatement: public IterationStatement {
 };
 
 
-class ForInStatement: public ForEachStatement {
+class ForInStatement V8_FINAL : public ForEachStatement {
  public:
   DECLARE_NODE_TYPE(ForInStatement)
 
@@ -926,8 +932,8 @@ class ForInStatement: public ForEachStatement {
 
   BailoutId BodyId() const { return body_id_; }
   BailoutId PrepareId() const { return prepare_id_; }
-  virtual BailoutId ContinueId() const { return EntryId(); }
-  virtual BailoutId StackCheckId() const { return body_id_; }
+  virtual BailoutId ContinueId() const V8_OVERRIDE { return EntryId(); }
+  virtual BailoutId StackCheckId() const V8_OVERRIDE { return body_id_; }
 
  protected:
   ForInStatement(Isolate* isolate, ZoneStringList* labels)
@@ -943,7 +949,7 @@ class ForInStatement: public ForEachStatement {
 };
 
 
-class ForOfStatement: public ForEachStatement {
+class ForOfStatement V8_FINAL : public ForEachStatement {
  public:
   DECLARE_NODE_TYPE(ForOfStatement)
 
@@ -985,8 +991,8 @@ class ForOfStatement: public ForEachStatement {
     return assign_each_;
   }
 
-  virtual BailoutId ContinueId() const { return EntryId(); }
-  virtual BailoutId StackCheckId() const { return BackEdgeId(); }
+  virtual BailoutId ContinueId() const V8_OVERRIDE { return EntryId(); }
+  virtual BailoutId StackCheckId() const V8_OVERRIDE { return BackEdgeId(); }
 
   BailoutId BackEdgeId() const { return back_edge_id_; }
 
@@ -1008,13 +1014,13 @@ class ForOfStatement: public ForEachStatement {
 };
 
 
-class ExpressionStatement: public Statement {
+class ExpressionStatement V8_FINAL : public Statement {
  public:
   DECLARE_NODE_TYPE(ExpressionStatement)
 
   void set_expression(Expression* e) { expression_ = e; }
   Expression* expression() const { return expression_; }
-  virtual bool IsJump() const { return expression_->IsThrow(); }
+  virtual bool IsJump() const V8_OVERRIDE { return expression_->IsThrow(); }
 
  protected:
   explicit ExpressionStatement(Expression* expression)
@@ -1025,16 +1031,16 @@ class ExpressionStatement: public Statement {
 };
 
 
-class JumpStatement: public Statement {
+class JumpStatement : public Statement {
  public:
-  virtual bool IsJump() const { return true; }
+  virtual bool IsJump() const V8_FINAL V8_OVERRIDE { return true; }
 
  protected:
   JumpStatement() {}
 };
 
 
-class ContinueStatement: public JumpStatement {
+class ContinueStatement V8_FINAL : public JumpStatement {
  public:
   DECLARE_NODE_TYPE(ContinueStatement)
 
@@ -1049,7 +1055,7 @@ class ContinueStatement: public JumpStatement {
 };
 
 
-class BreakStatement: public JumpStatement {
+class BreakStatement V8_FINAL : public JumpStatement {
  public:
   DECLARE_NODE_TYPE(BreakStatement)
 
@@ -1064,7 +1070,7 @@ class BreakStatement: public JumpStatement {
 };
 
 
-class ReturnStatement: public JumpStatement {
+class ReturnStatement V8_FINAL : public JumpStatement {
  public:
   DECLARE_NODE_TYPE(ReturnStatement)
 
@@ -1079,7 +1085,7 @@ class ReturnStatement: public JumpStatement {
 };
 
 
-class WithStatement: public Statement {
+class WithStatement V8_FINAL : public Statement {
  public:
   DECLARE_NODE_TYPE(WithStatement)
 
@@ -1100,7 +1106,7 @@ class WithStatement: public Statement {
 };
 
 
-class CaseClause: public ZoneObject {
+class CaseClause V8_FINAL : public ZoneObject {
  public:
   CaseClause(Isolate* isolate,
              Expression* label,
@@ -1137,7 +1143,7 @@ class CaseClause: public ZoneObject {
 };
 
 
-class SwitchStatement: public BreakableStatement {
+class SwitchStatement V8_FINAL : public BreakableStatement {
  public:
   DECLARE_NODE_TYPE(SwitchStatement)
 
@@ -1172,7 +1178,7 @@ class SwitchStatement: public BreakableStatement {
 // the parser implicitly creates an empty statement. Use the
 // HasThenStatement() and HasElseStatement() functions to check if a
 // given if-statement has a then- or an else-part containing code.
-class IfStatement: public Statement {
+class IfStatement V8_FINAL : public Statement {
  public:
   DECLARE_NODE_TYPE(IfStatement)
 
@@ -1183,7 +1189,7 @@ class IfStatement: public Statement {
   Statement* then_statement() const { return then_statement_; }
   Statement* else_statement() const { return else_statement_; }
 
-  virtual bool IsJump() const {
+  virtual bool IsJump() const V8_OVERRIDE {
     return HasThenStatement() && then_statement()->IsJump()
         && HasElseStatement() && else_statement()->IsJump();
   }
@@ -1217,7 +1223,7 @@ class IfStatement: public Statement {
 
 // NOTE: TargetCollectors are represented as nodes to fit in the target
 // stack in the compiler; this should probably be reworked.
-class TargetCollector: public AstNode {
+class TargetCollector V8_FINAL : public AstNode {
  public:
   explicit TargetCollector(Zone* zone) : targets_(0, zone) { }
 
@@ -1227,9 +1233,9 @@ class TargetCollector: public AstNode {
   void AddTarget(Label* target, Zone* zone);
 
   // Virtual behaviour. TargetCollectors are never part of the AST.
-  virtual void Accept(AstVisitor* v) { UNREACHABLE(); }
-  virtual NodeType node_type() const { return kInvalid; }
-  virtual TargetCollector* AsTargetCollector() { return this; }
+  virtual void Accept(AstVisitor* v) V8_OVERRIDE { UNREACHABLE(); }
+  virtual NodeType node_type() const V8_OVERRIDE { return kInvalid; }
+  virtual TargetCollector* AsTargetCollector() V8_OVERRIDE { return this; }
 
   ZoneList<Label*>* targets() { return &targets_; }
 
@@ -1238,7 +1244,7 @@ class TargetCollector: public AstNode {
 };
 
 
-class TryStatement: public Statement {
+class TryStatement : public Statement {
  public:
   void set_escaping_targets(ZoneList<Label*>* targets) {
     escaping_targets_ = targets;
@@ -1263,7 +1269,7 @@ class TryStatement: public Statement {
 };
 
 
-class TryCatchStatement: public TryStatement {
+class TryCatchStatement V8_FINAL : public TryStatement {
  public:
   DECLARE_NODE_TYPE(TryCatchStatement)
 
@@ -1290,7 +1296,7 @@ class TryCatchStatement: public TryStatement {
 };
 
 
-class TryFinallyStatement: public TryStatement {
+class TryFinallyStatement V8_FINAL : public TryStatement {
  public:
   DECLARE_NODE_TYPE(TryFinallyStatement)
 
@@ -1306,7 +1312,7 @@ class TryFinallyStatement: public TryStatement {
 };
 
 
-class DebuggerStatement: public Statement {
+class DebuggerStatement V8_FINAL : public Statement {
  public:
   DECLARE_NODE_TYPE(DebuggerStatement)
 
@@ -1315,7 +1321,7 @@ class DebuggerStatement: public Statement {
 };
 
 
-class EmptyStatement: public Statement {
+class EmptyStatement V8_FINAL : public Statement {
  public:
   DECLARE_NODE_TYPE(EmptyStatement)
 
@@ -1324,11 +1330,11 @@ class EmptyStatement: public Statement {
 };
 
 
-class Literal: public Expression {
+class Literal V8_FINAL : public Expression {
  public:
   DECLARE_NODE_TYPE(Literal)
 
-  virtual bool IsPropertyName() {
+  virtual bool IsPropertyName() V8_OVERRIDE {
     if (value_->IsInternalizedString()) {
       uint32_t ignored;
       return !String::cast(*value_)->AsArrayIndex(&ignored);
@@ -1341,8 +1347,12 @@ class Literal: public Expression {
     return Handle<String>::cast(value_);
   }
 
-  virtual bool ToBooleanIsTrue() { return value_->BooleanValue(); }
-  virtual bool ToBooleanIsFalse() { return !value_->BooleanValue(); }
+  virtual bool ToBooleanIsTrue() V8_OVERRIDE {
+    return value_->BooleanValue();
+  }
+  virtual bool ToBooleanIsFalse() V8_OVERRIDE {
+    return !value_->BooleanValue();
+  }
 
   // Identity testers.
   bool IsNull() const {
@@ -1385,7 +1395,7 @@ class Literal: public Expression {
 
 
 // Base class for literals that needs space in the corresponding JSFunction.
-class MaterializedLiteral: public Expression {
+class MaterializedLiteral : public Expression {
  public:
   virtual MaterializedLiteral* AsMaterializedLiteral() { return this; }
 
@@ -1417,7 +1427,7 @@ class MaterializedLiteral: public Expression {
 // Property is used for passing information
 // about an object literal's properties from the parser
 // to the code generator.
-class ObjectLiteralProperty: public ZoneObject {
+class ObjectLiteralProperty V8_FINAL : public ZoneObject {
  public:
   enum Kind {
     CONSTANT,              // Property with constant value (compile time).
@@ -1460,7 +1470,7 @@ class ObjectLiteralProperty: public ZoneObject {
 
 // An object literal has a boilerplate object that is used
 // for minimizing the work when constructing it at runtime.
-class ObjectLiteral: public MaterializedLiteral {
+class ObjectLiteral V8_FINAL : public MaterializedLiteral {
  public:
   typedef ObjectLiteralProperty Property;
 
@@ -1518,7 +1528,7 @@ class ObjectLiteral: public MaterializedLiteral {
 
 
 // Node for capturing a regexp literal.
-class RegExpLiteral: public MaterializedLiteral {
+class RegExpLiteral V8_FINAL : public MaterializedLiteral {
  public:
   DECLARE_NODE_TYPE(RegExpLiteral)
 
@@ -1541,7 +1551,7 @@ class RegExpLiteral: public MaterializedLiteral {
 
 // An array literal has a literals object that is used
 // for minimizing the work when constructing it at runtime.
-class ArrayLiteral: public MaterializedLiteral {
+class ArrayLiteral V8_FINAL : public MaterializedLiteral {
  public:
   DECLARE_NODE_TYPE(ArrayLiteral)
 
@@ -1572,11 +1582,11 @@ class ArrayLiteral: public MaterializedLiteral {
 };
 
 
-class VariableProxy: public Expression {
+class VariableProxy V8_FINAL : public Expression {
  public:
   DECLARE_NODE_TYPE(VariableProxy)
 
-  virtual bool IsValidLeftHandSide() {
+  virtual bool IsValidLeftHandSide() V8_OVERRIDE {
     return var_ == NULL ? true : var_->IsValidLeftHandSide();
   }
 
@@ -1624,15 +1634,15 @@ class VariableProxy: public Expression {
 };
 
 
-class Property: public Expression {
+class Property V8_FINAL : public Expression {
  public:
   DECLARE_NODE_TYPE(Property)
 
-  virtual bool IsValidLeftHandSide() { return true; }
+  virtual bool IsValidLeftHandSide() V8_OVERRIDE { return true; }
 
   Expression* obj() const { return obj_; }
   Expression* key() const { return key_; }
-  virtual int position() const { return pos_; }
+  virtual int position() const V8_OVERRIDE { return pos_; }
 
   BailoutId LoadId() const { return load_id_; }
 
@@ -1642,9 +1652,11 @@ class Property: public Expression {
 
   // Type feedback information.
   void RecordTypeFeedback(TypeFeedbackOracle* oracle, Zone* zone);
-  virtual bool IsMonomorphic() { return is_monomorphic_; }
-  virtual SmallMapList* GetReceiverTypes() { return &receiver_types_; }
-  virtual KeyedAccessStoreMode GetStoreMode() {
+  virtual bool IsMonomorphic() V8_OVERRIDE { return is_monomorphic_; }
+  virtual SmallMapList* GetReceiverTypes() V8_OVERRIDE {
+    return &receiver_types_;
+  }
+  virtual KeyedAccessStoreMode GetStoreMode() V8_OVERRIDE {
     return STANDARD_STORE;
   }
   bool IsUninitialized() { return is_uninitialized_; }
@@ -1681,19 +1693,21 @@ class Property: public Expression {
 };
 
 
-class Call: public Expression {
+class Call V8_FINAL : public Expression {
  public:
   DECLARE_NODE_TYPE(Call)
 
   Expression* expression() const { return expression_; }
   ZoneList<Expression*>* arguments() const { return arguments_; }
-  virtual int position() const { return pos_; }
+  virtual int position() const V8_FINAL { return pos_; }
 
   // Type feedback information.
   TypeFeedbackId CallFeedbackId() const { return reuse(id()); }
   void RecordTypeFeedback(TypeFeedbackOracle* oracle, CallKind call_kind);
-  virtual SmallMapList* GetReceiverTypes() { return &receiver_types_; }
-  virtual bool IsMonomorphic() { return is_monomorphic_; }
+  virtual SmallMapList* GetReceiverTypes() V8_OVERRIDE {
+    return &receiver_types_;
+  }
+  virtual bool IsMonomorphic() V8_OVERRIDE { return is_monomorphic_; }
   CheckType check_type() const { return check_type_; }
 
   void set_string_check(Handle<JSObject> holder) {
@@ -1764,18 +1778,18 @@ class Call: public Expression {
 };
 
 
-class CallNew: public Expression {
+class CallNew V8_FINAL : public Expression {
  public:
   DECLARE_NODE_TYPE(CallNew)
 
   Expression* expression() const { return expression_; }
   ZoneList<Expression*>* arguments() const { return arguments_; }
-  virtual int position() const { return pos_; }
+  virtual int position() const V8_OVERRIDE { return pos_; }
 
   // Type feedback information.
   TypeFeedbackId CallNewFeedbackId() const { return reuse(id()); }
   void RecordTypeFeedback(TypeFeedbackOracle* oracle);
-  virtual bool IsMonomorphic() { return is_monomorphic_; }
+  virtual bool IsMonomorphic() V8_OVERRIDE { return is_monomorphic_; }
   Handle<JSFunction> target() const { return target_; }
   ElementsKind elements_kind() const { return elements_kind_; }
   Handle<Cell> allocation_info_cell() const {
@@ -1815,7 +1829,7 @@ class CallNew: public Expression {
 // language construct. Instead it is used to call a C or JS function
 // with a set of arguments. This is used from the builtins that are
 // implemented in JavaScript (see "v8natives.js").
-class CallRuntime: public Expression {
+class CallRuntime V8_FINAL : public Expression {
  public:
   DECLARE_NODE_TYPE(CallRuntime)
 
@@ -1843,18 +1857,19 @@ class CallRuntime: public Expression {
 };
 
 
-class UnaryOperation: public Expression {
+class UnaryOperation V8_FINAL : public Expression {
  public:
   DECLARE_NODE_TYPE(UnaryOperation)
 
   Token::Value op() const { return op_; }
   Expression* expression() const { return expression_; }
-  virtual int position() const { return pos_; }
+  virtual int position() const V8_OVERRIDE { return pos_; }
 
   BailoutId MaterializeTrueId() { return materialize_true_id_; }
   BailoutId MaterializeFalseId() { return materialize_false_id_; }
 
-  virtual void RecordToBooleanTypeFeedback(TypeFeedbackOracle* oracle);
+  virtual void RecordToBooleanTypeFeedback(
+      TypeFeedbackOracle* oracle) V8_OVERRIDE;
 
  protected:
   UnaryOperation(Isolate* isolate,
@@ -1882,7 +1897,7 @@ class UnaryOperation: public Expression {
 };
 
 
-class BinaryOperation: public Expression {
+class BinaryOperation V8_FINAL : public Expression {
  public:
   DECLARE_NODE_TYPE(BinaryOperation)
 
@@ -1891,7 +1906,7 @@ class BinaryOperation: public Expression {
   Token::Value op() const { return op_; }
   Expression* left() const { return left_; }
   Expression* right() const { return right_; }
-  virtual int position() const { return pos_; }
+  virtual int position() const V8_OVERRIDE { return pos_; }
 
   BailoutId RightId() const { return right_id_; }
 
@@ -1899,7 +1914,8 @@ class BinaryOperation: public Expression {
   Maybe<int> fixed_right_arg() const { return fixed_right_arg_; }
   void set_fixed_right_arg(Maybe<int> arg) { fixed_right_arg_ = arg; }
 
-  virtual void RecordToBooleanTypeFeedback(TypeFeedbackOracle* oracle);
+  virtual void RecordToBooleanTypeFeedback(
+      TypeFeedbackOracle* oracle) V8_OVERRIDE;
 
  protected:
   BinaryOperation(Isolate* isolate,
@@ -1932,7 +1948,7 @@ class BinaryOperation: public Expression {
 };
 
 
-class CountOperation: public Expression {
+class CountOperation V8_FINAL : public Expression {
  public:
   DECLARE_NODE_TYPE(CountOperation)
 
@@ -1945,14 +1961,14 @@ class CountOperation: public Expression {
   }
 
   Expression* expression() const { return expression_; }
-  virtual int position() const { return pos_; }
-
-  virtual void MarkAsStatement() { is_prefix_ = true; }
+  virtual int position() const V8_OVERRIDE { return pos_; }
 
   void RecordTypeFeedback(TypeFeedbackOracle* oracle, Zone* znoe);
-  virtual bool IsMonomorphic() { return is_monomorphic_; }
-  virtual SmallMapList* GetReceiverTypes() { return &receiver_types_; }
-  virtual KeyedAccessStoreMode GetStoreMode() {
+  virtual bool IsMonomorphic() V8_OVERRIDE { return is_monomorphic_; }
+  virtual SmallMapList* GetReceiverTypes() V8_OVERRIDE {
+    return &receiver_types_;
+  }
+  virtual KeyedAccessStoreMode GetStoreMode() V8_OVERRIDE {
     return store_mode_;
   }
   TypeInfo type() const { return type_; }
@@ -1994,14 +2010,14 @@ class CountOperation: public Expression {
 };
 
 
-class CompareOperation: public Expression {
+class CompareOperation V8_FINAL : public Expression {
  public:
   DECLARE_NODE_TYPE(CompareOperation)
 
   Token::Value op() const { return op_; }
   Expression* left() const { return left_; }
   Expression* right() const { return right_; }
-  virtual int position() const { return pos_; }
+  virtual int position() const V8_OVERRIDE { return pos_; }
 
   // Type feedback information.
   TypeFeedbackId CompareOperationFeedbackId() const { return reuse(id()); }
@@ -2037,7 +2053,7 @@ class CompareOperation: public Expression {
 };
 
 
-class Conditional: public Expression {
+class Conditional V8_FINAL : public Expression {
  public:
   DECLARE_NODE_TYPE(Conditional)
 
@@ -2078,7 +2094,7 @@ class Conditional: public Expression {
 };
 
 
-class Assignment: public Expression {
+class Assignment V8_FINAL : public Expression {
  public:
   DECLARE_NODE_TYPE(Assignment)
 
@@ -2089,7 +2105,7 @@ class Assignment: public Expression {
   Token::Value op() const { return op_; }
   Expression* target() const { return target_; }
   Expression* value() const { return value_; }
-  virtual int position() const { return pos_; }
+  virtual int position() const V8_OVERRIDE { return pos_; }
   BinaryOperation* binary_operation() const { return binary_operation_; }
 
   // This check relies on the definition order of token in token.h.
@@ -2100,10 +2116,12 @@ class Assignment: public Expression {
   // Type feedback information.
   TypeFeedbackId AssignmentFeedbackId() { return reuse(id()); }
   void RecordTypeFeedback(TypeFeedbackOracle* oracle, Zone* zone);
-  virtual bool IsMonomorphic() { return is_monomorphic_; }
+  virtual bool IsMonomorphic() V8_OVERRIDE { return is_monomorphic_; }
   bool IsUninitialized() { return is_uninitialized_; }
-  virtual SmallMapList* GetReceiverTypes() { return &receiver_types_; }
-  virtual KeyedAccessStoreMode GetStoreMode() {
+  virtual SmallMapList* GetReceiverTypes() V8_OVERRIDE {
+    return &receiver_types_;
+  }
+  virtual KeyedAccessStoreMode GetStoreMode() V8_OVERRIDE {
     return store_mode_;
   }
 
@@ -2139,7 +2157,7 @@ class Assignment: public Expression {
 };
 
 
-class Yield: public Expression {
+class Yield V8_FINAL : public Expression {
  public:
   DECLARE_NODE_TYPE(Yield)
 
@@ -2153,7 +2171,7 @@ class Yield: public Expression {
   Expression* generator_object() const { return generator_object_; }
   Expression* expression() const { return expression_; }
   Kind yield_kind() const { return yield_kind_; }
-  virtual int position() const { return pos_; }
+  virtual int position() const V8_OVERRIDE { return pos_; }
 
   // Delegating yield surrounds the "yield" in a "try/catch".  This index
   // locates the catch handler in the handler table, and is equivalent to
@@ -2189,12 +2207,12 @@ class Yield: public Expression {
 };
 
 
-class Throw: public Expression {
+class Throw V8_FINAL : public Expression {
  public:
   DECLARE_NODE_TYPE(Throw)
 
   Expression* exception() const { return exception_; }
-  virtual int position() const { return pos_; }
+  virtual int position() const V8_OVERRIDE { return pos_; }
 
  protected:
   Throw(Isolate* isolate, Expression* exception, int pos)
@@ -2206,7 +2224,7 @@ class Throw: public Expression {
 };
 
 
-class FunctionLiteral: public Expression {
+class FunctionLiteral V8_FINAL : public Expression {
  public:
   enum FunctionType {
     ANONYMOUS_EXPRESSION,
@@ -2356,7 +2374,7 @@ class FunctionLiteral: public Expression {
 };
 
 
-class SharedFunctionInfoLiteral: public Expression {
+class SharedFunctionInfoLiteral V8_FINAL : public Expression {
  public:
   DECLARE_NODE_TYPE(SharedFunctionInfoLiteral)
 
@@ -2376,7 +2394,7 @@ class SharedFunctionInfoLiteral: public Expression {
 };
 
 
-class ThisFunction: public Expression {
+class ThisFunction V8_FINAL : public Expression {
  public:
   DECLARE_NODE_TYPE(ThisFunction)
 
@@ -2401,10 +2419,10 @@ class RegExpVisitor BASE_EMBEDDED {
 };
 
 
-class RegExpTree: public ZoneObject {
+class RegExpTree : public ZoneObject {
  public:
   static const int kInfinity = kMaxInt;
-  virtual ~RegExpTree() { }
+  virtual ~RegExpTree() {}
   virtual void* Accept(RegExpVisitor* visitor, void* data) = 0;
   virtual RegExpNode* ToNode(RegExpCompiler* compiler,
                              RegExpNode* on_success) = 0;
@@ -2426,19 +2444,19 @@ class RegExpTree: public ZoneObject {
 };
 
 
-class RegExpDisjunction: public RegExpTree {
+class RegExpDisjunction V8_FINAL : public RegExpTree {
  public:
   explicit RegExpDisjunction(ZoneList<RegExpTree*>* alternatives);
-  virtual void* Accept(RegExpVisitor* visitor, void* data);
+  virtual void* Accept(RegExpVisitor* visitor, void* data) V8_OVERRIDE;
   virtual RegExpNode* ToNode(RegExpCompiler* compiler,
-                             RegExpNode* on_success);
-  virtual RegExpDisjunction* AsDisjunction();
-  virtual Interval CaptureRegisters();
-  virtual bool IsDisjunction();
-  virtual bool IsAnchoredAtStart();
-  virtual bool IsAnchoredAtEnd();
-  virtual int min_match() { return min_match_; }
-  virtual int max_match() { return max_match_; }
+                             RegExpNode* on_success) V8_OVERRIDE;
+  virtual RegExpDisjunction* AsDisjunction() V8_OVERRIDE;
+  virtual Interval CaptureRegisters() V8_OVERRIDE;
+  virtual bool IsDisjunction() V8_OVERRIDE;
+  virtual bool IsAnchoredAtStart() V8_OVERRIDE;
+  virtual bool IsAnchoredAtEnd() V8_OVERRIDE;
+  virtual int min_match() V8_OVERRIDE { return min_match_; }
+  virtual int max_match() V8_OVERRIDE { return max_match_; }
   ZoneList<RegExpTree*>* alternatives() { return alternatives_; }
  private:
   ZoneList<RegExpTree*>* alternatives_;
@@ -2447,19 +2465,19 @@ class RegExpDisjunction: public RegExpTree {
 };
 
 
-class RegExpAlternative: public RegExpTree {
+class RegExpAlternative V8_FINAL : public RegExpTree {
  public:
   explicit RegExpAlternative(ZoneList<RegExpTree*>* nodes);
-  virtual void* Accept(RegExpVisitor* visitor, void* data);
+  virtual void* Accept(RegExpVisitor* visitor, void* data) V8_OVERRIDE;
   virtual RegExpNode* ToNode(RegExpCompiler* compiler,
-                             RegExpNode* on_success);
-  virtual RegExpAlternative* AsAlternative();
-  virtual Interval CaptureRegisters();
-  virtual bool IsAlternative();
-  virtual bool IsAnchoredAtStart();
-  virtual bool IsAnchoredAtEnd();
-  virtual int min_match() { return min_match_; }
-  virtual int max_match() { return max_match_; }
+                             RegExpNode* on_success) V8_OVERRIDE;
+  virtual RegExpAlternative* AsAlternative() V8_OVERRIDE;
+  virtual Interval CaptureRegisters() V8_OVERRIDE;
+  virtual bool IsAlternative() V8_OVERRIDE;
+  virtual bool IsAnchoredAtStart() V8_OVERRIDE;
+  virtual bool IsAnchoredAtEnd() V8_OVERRIDE;
+  virtual int min_match() V8_OVERRIDE { return min_match_; }
+  virtual int max_match() V8_OVERRIDE { return max_match_; }
   ZoneList<RegExpTree*>* nodes() { return nodes_; }
  private:
   ZoneList<RegExpTree*>* nodes_;
@@ -2468,7 +2486,7 @@ class RegExpAlternative: public RegExpTree {
 };
 
 
-class RegExpAssertion: public RegExpTree {
+class RegExpAssertion V8_FINAL : public RegExpTree {
  public:
   enum AssertionType {
     START_OF_LINE,
@@ -2479,22 +2497,22 @@ class RegExpAssertion: public RegExpTree {
     NON_BOUNDARY
   };
   explicit RegExpAssertion(AssertionType type) : assertion_type_(type) { }
-  virtual void* Accept(RegExpVisitor* visitor, void* data);
+  virtual void* Accept(RegExpVisitor* visitor, void* data) V8_OVERRIDE;
   virtual RegExpNode* ToNode(RegExpCompiler* compiler,
-                             RegExpNode* on_success);
-  virtual RegExpAssertion* AsAssertion();
-  virtual bool IsAssertion();
-  virtual bool IsAnchoredAtStart();
-  virtual bool IsAnchoredAtEnd();
-  virtual int min_match() { return 0; }
-  virtual int max_match() { return 0; }
+                             RegExpNode* on_success) V8_OVERRIDE;
+  virtual RegExpAssertion* AsAssertion() V8_OVERRIDE;
+  virtual bool IsAssertion() V8_OVERRIDE;
+  virtual bool IsAnchoredAtStart() V8_OVERRIDE;
+  virtual bool IsAnchoredAtEnd() V8_OVERRIDE;
+  virtual int min_match() V8_OVERRIDE { return 0; }
+  virtual int max_match() V8_OVERRIDE { return 0; }
   AssertionType assertion_type() { return assertion_type_; }
  private:
   AssertionType assertion_type_;
 };
 
 
-class CharacterSet BASE_EMBEDDED {
+class CharacterSet V8_FINAL BASE_EMBEDDED {
  public:
   explicit CharacterSet(uc16 standard_set_type)
       : ranges_(NULL),
@@ -2517,7 +2535,7 @@ class CharacterSet BASE_EMBEDDED {
 };
 
 
-class RegExpCharacterClass: public RegExpTree {
+class RegExpCharacterClass V8_FINAL : public RegExpTree {
  public:
   RegExpCharacterClass(ZoneList<CharacterRange>* ranges, bool is_negated)
       : set_(ranges),
@@ -2525,15 +2543,15 @@ class RegExpCharacterClass: public RegExpTree {
   explicit RegExpCharacterClass(uc16 type)
       : set_(type),
         is_negated_(false) { }
-  virtual void* Accept(RegExpVisitor* visitor, void* data);
+  virtual void* Accept(RegExpVisitor* visitor, void* data) V8_OVERRIDE;
   virtual RegExpNode* ToNode(RegExpCompiler* compiler,
-                             RegExpNode* on_success);
-  virtual RegExpCharacterClass* AsCharacterClass();
-  virtual bool IsCharacterClass();
-  virtual bool IsTextElement() { return true; }
-  virtual int min_match() { return 1; }
-  virtual int max_match() { return 1; }
-  virtual void AppendToText(RegExpText* text, Zone* zone);
+                             RegExpNode* on_success) V8_OVERRIDE;
+  virtual RegExpCharacterClass* AsCharacterClass() V8_OVERRIDE;
+  virtual bool IsCharacterClass() V8_OVERRIDE;
+  virtual bool IsTextElement() V8_OVERRIDE { return true; }
+  virtual int min_match() V8_OVERRIDE { return 1; }
+  virtual int max_match() V8_OVERRIDE { return 1; }
+  virtual void AppendToText(RegExpText* text, Zone* zone) V8_OVERRIDE;
   CharacterSet character_set() { return set_; }
   // TODO(lrn): Remove need for complex version if is_standard that
   // recognizes a mangled standard set and just do { return set_.is_special(); }
@@ -2559,18 +2577,18 @@ class RegExpCharacterClass: public RegExpTree {
 };
 
 
-class RegExpAtom: public RegExpTree {
+class RegExpAtom V8_FINAL : public RegExpTree {
  public:
   explicit RegExpAtom(Vector<const uc16> data) : data_(data) { }
-  virtual void* Accept(RegExpVisitor* visitor, void* data);
+  virtual void* Accept(RegExpVisitor* visitor, void* data) V8_OVERRIDE;
   virtual RegExpNode* ToNode(RegExpCompiler* compiler,
-                             RegExpNode* on_success);
-  virtual RegExpAtom* AsAtom();
-  virtual bool IsAtom();
-  virtual bool IsTextElement() { return true; }
-  virtual int min_match() { return data_.length(); }
-  virtual int max_match() { return data_.length(); }
-  virtual void AppendToText(RegExpText* text, Zone* zone);
+                             RegExpNode* on_success) V8_OVERRIDE;
+  virtual RegExpAtom* AsAtom() V8_OVERRIDE;
+  virtual bool IsAtom() V8_OVERRIDE;
+  virtual bool IsTextElement() V8_OVERRIDE { return true; }
+  virtual int min_match() V8_OVERRIDE { return data_.length(); }
+  virtual int max_match() V8_OVERRIDE { return data_.length(); }
+  virtual void AppendToText(RegExpText* text, Zone* zone) V8_OVERRIDE;
   Vector<const uc16> data() { return data_; }
   int length() { return data_.length(); }
  private:
@@ -2578,18 +2596,18 @@ class RegExpAtom: public RegExpTree {
 };
 
 
-class RegExpText: public RegExpTree {
+class RegExpText V8_FINAL : public RegExpTree {
  public:
   explicit RegExpText(Zone* zone) : elements_(2, zone), length_(0) {}
-  virtual void* Accept(RegExpVisitor* visitor, void* data);
+  virtual void* Accept(RegExpVisitor* visitor, void* data) V8_OVERRIDE;
   virtual RegExpNode* ToNode(RegExpCompiler* compiler,
-                             RegExpNode* on_success);
-  virtual RegExpText* AsText();
-  virtual bool IsText();
-  virtual bool IsTextElement() { return true; }
-  virtual int min_match() { return length_; }
-  virtual int max_match() { return length_; }
-  virtual void AppendToText(RegExpText* text, Zone* zone);
+                             RegExpNode* on_success) V8_OVERRIDE;
+  virtual RegExpText* AsText() V8_OVERRIDE;
+  virtual bool IsText() V8_OVERRIDE;
+  virtual bool IsTextElement() V8_OVERRIDE { return true; }
+  virtual int min_match() V8_OVERRIDE { return length_; }
+  virtual int max_match() V8_OVERRIDE { return length_; }
+  virtual void AppendToText(RegExpText* text, Zone* zone) V8_OVERRIDE;
   void AddElement(TextElement elm, Zone* zone)  {
     elements_.Add(elm, zone);
     length_ += elm.length();
@@ -2601,7 +2619,7 @@ class RegExpText: public RegExpTree {
 };
 
 
-class RegExpQuantifier: public RegExpTree {
+class RegExpQuantifier V8_FINAL : public RegExpTree {
  public:
   enum QuantifierType { GREEDY, NON_GREEDY, POSSESSIVE };
   RegExpQuantifier(int min, int max, QuantifierType type, RegExpTree* body)
@@ -2616,9 +2634,9 @@ class RegExpQuantifier: public RegExpTree {
       max_match_ = max * body->max_match();
     }
   }
-  virtual void* Accept(RegExpVisitor* visitor, void* data);
+  virtual void* Accept(RegExpVisitor* visitor, void* data) V8_OVERRIDE;
   virtual RegExpNode* ToNode(RegExpCompiler* compiler,
-                             RegExpNode* on_success);
+                             RegExpNode* on_success) V8_OVERRIDE;
   static RegExpNode* ToNode(int min,
                             int max,
                             bool is_greedy,
@@ -2626,11 +2644,11 @@ class RegExpQuantifier: public RegExpTree {
                             RegExpCompiler* compiler,
                             RegExpNode* on_success,
                             bool not_at_start = false);
-  virtual RegExpQuantifier* AsQuantifier();
-  virtual Interval CaptureRegisters();
-  virtual bool IsQuantifier();
-  virtual int min_match() { return min_match_; }
-  virtual int max_match() { return max_match_; }
+  virtual RegExpQuantifier* AsQuantifier() V8_OVERRIDE;
+  virtual Interval CaptureRegisters() V8_OVERRIDE;
+  virtual bool IsQuantifier() V8_OVERRIDE;
+  virtual int min_match() V8_OVERRIDE { return min_match_; }
+  virtual int max_match() V8_OVERRIDE { return max_match_; }
   int min() { return min_; }
   int max() { return max_; }
   bool is_possessive() { return quantifier_type_ == POSSESSIVE; }
@@ -2648,24 +2666,24 @@ class RegExpQuantifier: public RegExpTree {
 };
 
 
-class RegExpCapture: public RegExpTree {
+class RegExpCapture V8_FINAL : public RegExpTree {
  public:
   explicit RegExpCapture(RegExpTree* body, int index)
       : body_(body), index_(index) { }
-  virtual void* Accept(RegExpVisitor* visitor, void* data);
+  virtual void* Accept(RegExpVisitor* visitor, void* data) V8_OVERRIDE;
   virtual RegExpNode* ToNode(RegExpCompiler* compiler,
-                             RegExpNode* on_success);
+                             RegExpNode* on_success) V8_OVERRIDE;
   static RegExpNode* ToNode(RegExpTree* body,
                             int index,
                             RegExpCompiler* compiler,
                             RegExpNode* on_success);
-  virtual RegExpCapture* AsCapture();
-  virtual bool IsAnchoredAtStart();
-  virtual bool IsAnchoredAtEnd();
-  virtual Interval CaptureRegisters();
-  virtual bool IsCapture();
-  virtual int min_match() { return body_->min_match(); }
-  virtual int max_match() { return body_->max_match(); }
+  virtual RegExpCapture* AsCapture() V8_OVERRIDE;
+  virtual bool IsAnchoredAtStart() V8_OVERRIDE;
+  virtual bool IsAnchoredAtEnd() V8_OVERRIDE;
+  virtual Interval CaptureRegisters() V8_OVERRIDE;
+  virtual bool IsCapture() V8_OVERRIDE;
+  virtual int min_match() V8_OVERRIDE { return body_->min_match(); }
+  virtual int max_match() V8_OVERRIDE { return body_->max_match(); }
   RegExpTree* body() { return body_; }
   int index() { return index_; }
   static int StartRegister(int index) { return index * 2; }
@@ -2677,7 +2695,7 @@ class RegExpCapture: public RegExpTree {
 };
 
 
-class RegExpLookahead: public RegExpTree {
+class RegExpLookahead V8_FINAL : public RegExpTree {
  public:
   RegExpLookahead(RegExpTree* body,
                   bool is_positive,
@@ -2688,15 +2706,15 @@ class RegExpLookahead: public RegExpTree {
         capture_count_(capture_count),
         capture_from_(capture_from) { }
 
-  virtual void* Accept(RegExpVisitor* visitor, void* data);
+  virtual void* Accept(RegExpVisitor* visitor, void* data) V8_OVERRIDE;
   virtual RegExpNode* ToNode(RegExpCompiler* compiler,
-                             RegExpNode* on_success);
-  virtual RegExpLookahead* AsLookahead();
-  virtual Interval CaptureRegisters();
-  virtual bool IsLookahead();
-  virtual bool IsAnchoredAtStart();
-  virtual int min_match() { return 0; }
-  virtual int max_match() { return 0; }
+                             RegExpNode* on_success) V8_OVERRIDE;
+  virtual RegExpLookahead* AsLookahead() V8_OVERRIDE;
+  virtual Interval CaptureRegisters() V8_OVERRIDE;
+  virtual bool IsLookahead() V8_OVERRIDE;
+  virtual bool IsAnchoredAtStart() V8_OVERRIDE;
+  virtual int min_match() V8_OVERRIDE { return 0; }
+  virtual int max_match() V8_OVERRIDE { return 0; }
   RegExpTree* body() { return body_; }
   bool is_positive() { return is_positive_; }
   int capture_count() { return capture_count_; }
@@ -2710,17 +2728,17 @@ class RegExpLookahead: public RegExpTree {
 };
 
 
-class RegExpBackReference: public RegExpTree {
+class RegExpBackReference V8_FINAL : public RegExpTree {
  public:
   explicit RegExpBackReference(RegExpCapture* capture)
       : capture_(capture) { }
-  virtual void* Accept(RegExpVisitor* visitor, void* data);
+  virtual void* Accept(RegExpVisitor* visitor, void* data) V8_OVERRIDE;
   virtual RegExpNode* ToNode(RegExpCompiler* compiler,
-                             RegExpNode* on_success);
-  virtual RegExpBackReference* AsBackReference();
-  virtual bool IsBackReference();
-  virtual int min_match() { return 0; }
-  virtual int max_match() { return capture_->max_match(); }
+                             RegExpNode* on_success) V8_OVERRIDE;
+  virtual RegExpBackReference* AsBackReference() V8_OVERRIDE;
+  virtual bool IsBackReference() V8_OVERRIDE;
+  virtual int min_match() V8_OVERRIDE { return 0; }
+  virtual int max_match() V8_OVERRIDE { return capture_->max_match(); }
   int index() { return capture_->index(); }
   RegExpCapture* capture() { return capture_; }
  private:
@@ -2728,16 +2746,16 @@ class RegExpBackReference: public RegExpTree {
 };
 
 
-class RegExpEmpty: public RegExpTree {
+class RegExpEmpty V8_FINAL : public RegExpTree {
  public:
   RegExpEmpty() { }
-  virtual void* Accept(RegExpVisitor* visitor, void* data);
+  virtual void* Accept(RegExpVisitor* visitor, void* data) V8_OVERRIDE;
   virtual RegExpNode* ToNode(RegExpCompiler* compiler,
-                             RegExpNode* on_success);
-  virtual RegExpEmpty* AsEmpty();
-  virtual bool IsEmpty();
-  virtual int min_match() { return 0; }
-  virtual int max_match() { return 0; }
+                             RegExpNode* on_success) V8_OVERRIDE;
+  virtual RegExpEmpty* AsEmpty() V8_OVERRIDE;
+  virtual bool IsEmpty() V8_OVERRIDE;
+  virtual int min_match() V8_OVERRIDE { return 0; }
+  virtual int max_match() V8_OVERRIDE { return 0; }
   static RegExpEmpty* GetInstance() {
     static RegExpEmpty* instance = ::new RegExpEmpty();
     return instance;
@@ -2761,7 +2779,7 @@ inline ModuleVariable::ModuleVariable(VariableProxy* proxy)
 class AstVisitor BASE_EMBEDDED {
  public:
   AstVisitor() {}
-  virtual ~AstVisitor() { }
+  virtual ~AstVisitor() {}
 
   // Stack overflow check and dynamic dispatch.
   virtual void Visit(AstNode* node) = 0;
@@ -2781,7 +2799,7 @@ class AstVisitor BASE_EMBEDDED {
 
 #define DEFINE_AST_VISITOR_SUBCLASS_MEMBERS()                       \
 public:                                                             \
-  virtual void Visit(AstNode* node) {                               \
+  virtual void Visit(AstNode* node) V8_FINAL V8_OVERRIDE {                \
     if (!CheckStackOverflow()) node->Accept(this);                  \
   }                                                                 \
                                                                     \
@@ -2847,7 +2865,7 @@ class AstNullVisitor BASE_EMBEDDED {
 // AstNode factory
 
 template<class Visitor>
-class AstNodeFactory BASE_EMBEDDED {
+class AstNodeFactory V8_FINAL BASE_EMBEDDED {
  public:
   AstNodeFactory(Isolate* isolate, Zone* zone)
       : isolate_(isolate),
diff --git a/src/hydrogen-instructions.h b/src/hydrogen-instructions.h
index 887168cc75..bef46df4ec 100644
--- a/src/hydrogen-instructions.h
+++ b/src/hydrogen-instructions.h
@@ -210,24 +210,27 @@ class LChunkBuilder;
   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),
@@ -302,7 +305,7 @@ class Range: public ZoneObject {
 };
 
 
-class UniqueValueId {
+class UniqueValueId V8_FINAL {
  public:
   UniqueValueId() : raw_address_(NULL) { }
 
@@ -344,7 +347,7 @@ class UniqueValueId {
 };
 
 
-class HType {
+class HType V8_FINAL {
  public:
   static HType None() { return HType(kNone); }
   static HType Tagged() { return HType(kTagged); }
@@ -495,7 +498,7 @@ class HUseListNode: public ZoneObject {
 
 // 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();
@@ -539,7 +542,7 @@ enum GVNFlag {
 };
 
 
-class DecompositionResult BASE_EMBEDDED {
+class DecompositionResult V8_FINAL BASE_EMBEDDED {
  public:
   DecompositionResult() : base_(NULL), offset_(0), scale_(0) {}
 
@@ -587,7 +590,7 @@ class DecompositionResult BASE_EMBEDDED {
 typedef EnumSet<GVNFlag> GVNFlagSet;
 
 
-class HValue: public ZoneObject {
+class HValue : public ZoneObject {
  public:
   static const int kNoNumber = -1;
 
@@ -1082,12 +1085,12 @@ class HValue: public ZoneObject {
   }
 
 
-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; }
@@ -1109,7 +1112,7 @@ class HInstruction: public HValue {
   virtual LInstruction* CompileToLithium(LChunkBuilder* builder) = 0;
 
 #ifdef DEBUG
-  virtual void Verify();
+  virtual void Verify() V8_OVERRIDE;
 #endif
 
   virtual bool IsCall() { return false; }
@@ -1125,7 +1128,7 @@ class HInstruction: public HValue {
     SetGVNFlag(kDependsOnOsrEntries);
   }
 
-  virtual void DeleteFromGraph() { Unlink(); }
+  virtual void DeleteFromGraph() V8_OVERRIDE { Unlink(); }
 
  private:
   void InitializeAsFirst(HBasicBlock* block) {
@@ -1146,26 +1149,30 @@ class HInstruction: public HValue {
 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;
@@ -1178,7 +1185,7 @@ class HControlInstruction: public HInstruction {
 };
 
 
-class HSuccessorIterator BASE_EMBEDDED {
+class HSuccessorIterator V8_FINAL BASE_EMBEDDED {
  public:
   explicit HSuccessorIterator(HControlInstruction* instr)
       : instr_(instr), current_(0) { }
@@ -1194,18 +1201,22 @@ class HSuccessorIterator BASE_EMBEDDED {
 
 
 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_;
@@ -1213,9 +1224,9 @@ class HTemplateControlInstruction: public HControlInstruction {
 };
 
 
-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();
   }
 
@@ -1223,7 +1234,7 @@ class HBlockEntry: public HTemplateInstruction<0> {
 };
 
 
-class HDummyUse: public HTemplateInstruction<1> {
+class HDummyUse V8_FINAL : public HTemplateInstruction<1> {
  public:
   explicit HDummyUse(HValue* value)
       : HTemplateInstruction<1>(HType::Smi()) {
@@ -1235,23 +1246,23 @@ class HDummyUse: public HTemplateInstruction<1> {
 
   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_P2(HDeoptimize, const char*,
                                  Deoptimizer::BailoutType);
 
-  virtual Representation RequiredInputRepresentation(int index) {
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     return Representation::None();
   }
 
@@ -1270,9 +1281,9 @@ class HDeoptimize: public HTemplateInstruction<0> {
 
 
 // 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();
   }
 
@@ -1280,23 +1291,23 @@ class HDebugBreak: public HTemplateInstruction<0> {
 };
 
 
-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,
@@ -1306,13 +1317,13 @@ class HUnaryControlInstruction: public HTemplateControlInstruction<2, 1> {
     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(),
@@ -1323,10 +1334,10 @@ class HBranch: public HUnaryControlInstruction {
     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_;
@@ -1339,7 +1350,7 @@ class HBranch: public HUnaryControlInstruction {
 };
 
 
-class HCompareMap: public HUnaryControlInstruction {
+class HCompareMap V8_FINAL : public HUnaryControlInstruction {
  public:
   HCompareMap(HValue* value,
               Handle<Map> map,
@@ -1350,11 +1361,11 @@ class HCompareMap: public HUnaryControlInstruction {
     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();
   }
 
@@ -1365,20 +1376,20 @@ class HCompareMap: public HUnaryControlInstruction {
 };
 
 
-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() {
@@ -1386,11 +1397,11 @@ class HContext: public HTemplateInstruction<0> {
     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,
@@ -1405,11 +1416,11 @@ class HReturn: public HTemplateControlInstruction<0, 3> {
     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); }
@@ -1426,9 +1437,9 @@ class HReturn: public HTemplateControlInstruction<0, 3> {
 };
 
 
-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();
   }
 
@@ -1436,7 +1447,7 @@ class HAbnormalExit: public HTemplateControlInstruction<0, 0> {
 };
 
 
-class HUnaryOperation: public HTemplateInstruction<1> {
+class HUnaryOperation : public HTemplateInstruction<1> {
  public:
   HUnaryOperation(HValue* value, HType type = HType::Tagged())
       : HTemplateInstruction<1>(type) {
@@ -1448,11 +1459,11 @@ class HUnaryOperation: public HTemplateInstruction<1> {
   }
 
   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,
@@ -1460,7 +1471,7 @@ class HThrow: public HTemplateInstruction<2> {
     return new(zone) HThrow(context, value);
   }
 
-  virtual Representation RequiredInputRepresentation(int index) {
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     return Representation::Tagged();
   }
 
@@ -1478,11 +1489,11 @@ class HThrow: public HTemplateInstruction<2> {
 };
 
 
-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();
   }
 
@@ -1493,19 +1504,20 @@ class HUseConst: public HUnaryOperation {
 };
 
 
-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)
 
@@ -1517,7 +1529,7 @@ class HForceRepresentation: public HTemplateInstruction<1> {
 };
 
 
-class HChange: public HUnaryOperation {
+class HChange V8_FINAL : public HUnaryOperation {
  public:
   HChange(HValue* value,
           Representation to,
@@ -1543,47 +1555,48 @@ class HChange: public HUnaryOperation {
     return CheckUsesForFlag(kAllowUndefinedAsNaN);
   }
 
-  virtual HValue* EnsureAndPropagateNotMinusZero(BitVector* visited);
-  virtual HType CalculateInferredType();
-  virtual HValue* Canonicalize();
+  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 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)
@@ -1593,7 +1606,7 @@ class HClampToUint8: public HUnaryOperation {
     SetFlag(kUseGVN);
   }
 
-  virtual bool IsDeletable() const { return true; }
+  virtual bool IsDeletable() const V8_OVERRIDE { return true; }
 };
 
 
@@ -1603,7 +1616,7 @@ enum RemovableSimulate {
 };
 
 
-class HSimulate: public HInstruction {
+class HSimulate V8_FINAL : public HInstruction {
  public:
   HSimulate(BailoutId ast_id,
             int pop_count,
@@ -1615,9 +1628,9 @@ class HSimulate: public HInstruction {
         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_; }
@@ -1647,11 +1660,13 @@ class HSimulate: public HInstruction {
     }
     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();
   }
 
@@ -1661,13 +1676,13 @@ class HSimulate: public HInstruction {
   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;
   }
 
@@ -1700,7 +1715,7 @@ class HSimulate: public HInstruction {
 };
 
 
-class HEnvironmentMarker: public HTemplateInstruction<1> {
+class HEnvironmentMarker V8_FINAL : public HTemplateInstruction<1> {
  public:
   enum Kind { BIND, LOOKUP };
 
@@ -1714,11 +1729,11 @@ class HEnvironmentMarker: public HTemplateInstruction<1> {
     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) {
@@ -1742,7 +1757,7 @@ class HEnvironmentMarker: public HTemplateInstruction<1> {
 };
 
 
-class HStackCheck: public HTemplateInstruction<1> {
+class HStackCheck V8_FINAL : public HTemplateInstruction<1> {
  public:
   enum Type {
     kFunctionEntry,
@@ -1753,7 +1768,7 @@ class HStackCheck: public HTemplateInstruction<1> {
 
   HValue* context() { return OperandAt(0); }
 
-  virtual Representation RequiredInputRepresentation(int index) {
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     return Representation::Tagged();
   }
 
@@ -1792,7 +1807,7 @@ enum InliningKind {
 class HArgumentsObject;
 
 
-class HEnterInlined: public HTemplateInstruction<0> {
+class HEnterInlined V8_FINAL : public HTemplateInstruction<0> {
  public:
   static HEnterInlined* New(Zone* zone,
                             HValue* context,
@@ -1811,7 +1826,7 @@ class HEnterInlined: public HTemplateInstruction<0> {
   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_; }
@@ -1821,7 +1836,7 @@ class HEnterInlined: public HTemplateInstruction<0> {
   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();
   }
 
@@ -1862,11 +1877,11 @@ class HEnterInlined: public HTemplateInstruction<0> {
 };
 
 
-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();
   }
 
@@ -1874,11 +1889,11 @@ class HLeaveInlined: public HTemplateInstruction<0> {
 };
 
 
-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();
   }
 
@@ -1893,39 +1908,39 @@ class HPushArgument: public HUnaryOperation {
 };
 
 
-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) {
@@ -1933,11 +1948,11 @@ class HOuterContext: public HUnaryOperation {
     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,
@@ -1962,7 +1977,7 @@ class HDeclareGlobals: public HUnaryOperation {
 
   DECLARE_CONCRETE_INSTRUCTION(DeclareGlobals)
 
-  virtual Representation RequiredInputRepresentation(int index) {
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     return Representation::Tagged();
   }
 
@@ -1972,7 +1987,7 @@ class HDeclareGlobals: public HUnaryOperation {
 };
 
 
-class HGlobalObject: public HUnaryOperation {
+class HGlobalObject V8_FINAL : public HUnaryOperation {
  public:
   explicit HGlobalObject(HValue* context) : HUnaryOperation(context) {
     set_representation(Representation::Tagged());
@@ -1985,30 +2000,30 @@ class HGlobalObject: public HUnaryOperation {
 
   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)
@@ -2017,12 +2032,12 @@ class HGlobalReceiver: public HUnaryOperation {
     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) {
@@ -2030,35 +2045,38 @@ class HCall: public HTemplateInstruction<V> {
     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) {
@@ -2066,9 +2084,10 @@ class HBinaryCall: public HCall<2> {
     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();
   }
 
@@ -2077,7 +2096,7 @@ class HBinaryCall: public HCall<2> {
 };
 
 
-class HInvokeFunction: public HBinaryCall {
+class HInvokeFunction V8_FINAL : public HBinaryCall {
  public:
   HInvokeFunction(HValue* context, HValue* function, int argument_count)
       : HBinaryCall(context, function, argument_count) {
@@ -2109,10 +2128,6 @@ class HInvokeFunction: public HBinaryCall {
                                      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_; }
@@ -2126,7 +2141,7 @@ class HInvokeFunction: public HBinaryCall {
 };
 
 
-class HCallConstantFunction: public HCall<0> {
+class HCallConstantFunction V8_FINAL : public HCall<0> {
  public:
   HCallConstantFunction(Handle<JSFunction> function, int argument_count)
       : HCall<0>(argument_count),
@@ -2141,9 +2156,9 @@ class HCallConstantFunction: public HCall<0> {
         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();
   }
 
@@ -2155,16 +2170,12 @@ class HCallConstantFunction: public HCall<0> {
 };
 
 
-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(); }
 
@@ -2172,29 +2183,25 @@ class HCallKeyed: public HBinaryCall {
 };
 
 
-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) {
@@ -2210,15 +2217,11 @@ class HCallFunction: public HBinaryCall {
   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) {
@@ -2231,15 +2234,11 @@ class HCallGlobal: public HUnaryCall {
     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:
@@ -2247,19 +2246,19 @@ class HCallGlobal: public HUnaryCall {
 };
 
 
-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();
   }
 
@@ -2271,15 +2270,10 @@ class HCallKnownGlobal: public HCall<0> {
 };
 
 
-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(); }
@@ -2288,15 +2282,18 @@ class HCallNew: public HBinaryCall {
 };
 
 
-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_;
@@ -2312,7 +2309,7 @@ class HCallNewArray: public HCallNew {
 };
 
 
-class HCallRuntime: public HCall<1> {
+class HCallRuntime V8_FINAL : public HCall<1> {
  public:
   static HCallRuntime* New(Zone* zone,
                            HValue* context,
@@ -2322,13 +2319,13 @@ class HCallRuntime: public HCall<1> {
     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();
   }
 
@@ -2348,18 +2345,18 @@ class HCallRuntime: public HCall<1> {
 };
 
 
-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)
@@ -2369,11 +2366,11 @@ class HMapEnumLength: public HUnaryOperation {
     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());
@@ -2381,21 +2378,21 @@ class HElementsKind: public HUnaryOperation {
     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,
@@ -2405,11 +2402,12 @@ class HUnaryMathOperation: public HTemplateInstruction<2> {
   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 {
@@ -2433,10 +2431,10 @@ class HUnaryMathOperation: public HTemplateInstruction<2> {
     }
   }
 
-  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;
@@ -2444,7 +2442,7 @@ class HUnaryMathOperation: public HTemplateInstruction<2> {
   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();
   }
@@ -2486,28 +2484,28 @@ class HUnaryMathOperation: public HTemplateInstruction<2> {
     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)
@@ -2520,11 +2518,11 @@ class HLoadExternalArrayPointer: public HUnaryOperation {
     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,
@@ -2542,13 +2540,13 @@ class HCheckMaps: public HTemplateInstruction<2> {
 
   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_; }
@@ -2557,12 +2555,12 @@ class HCheckMaps: public HTemplateInstruction<2> {
     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.
@@ -2617,22 +2615,22 @@ class HCheckMaps: public HTemplateInstruction<2> {
 };
 
 
-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_);
   }
 
@@ -2642,7 +2640,7 @@ class HCheckFunction: public HUnaryOperation {
   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_;
   }
@@ -2662,7 +2660,7 @@ class HCheckFunction: public HUnaryOperation {
 };
 
 
-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);
@@ -2678,13 +2676,13 @@ class HCheckInstanceType: public HUnaryOperation {
     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);
@@ -2696,7 +2694,7 @@ class HCheckInstanceType: public HUnaryOperation {
   // 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_;
   }
@@ -2722,15 +2720,15 @@ class HCheckInstanceType: public HUnaryOperation {
 };
 
 
-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;
@@ -2741,7 +2739,7 @@ class HCheckSmi: public HUnaryOperation {
   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()) {
@@ -2751,14 +2749,14 @@ class HCheckSmi: public HUnaryOperation {
 };
 
 
-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();
   }
 
@@ -2766,27 +2764,27 @@ class HIsNumberAndBranch: public HUnaryControlInstruction {
 };
 
 
-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)
@@ -2818,7 +2816,7 @@ class HConstant;
 class HBitwise;
 
 
-class InductionVariableData : public ZoneObject {
+class InductionVariableData V8_FINAL : public ZoneObject {
  public:
   class InductionVariableCheck : public ZoneObject {
    public:
@@ -3018,7 +3016,7 @@ class InductionVariableData : public ZoneObject {
 };
 
 
-class HPhi: public HValue {
+class HPhi V8_FINAL : public HValue {
  public:
   HPhi(int merged_index, Zone* zone)
       : inputs_(2, zone),
@@ -3034,19 +3032,22 @@ class HPhi: public HValue {
     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();
@@ -3071,10 +3072,10 @@ class HPhi: public HValue {
     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);
@@ -3111,7 +3112,7 @@ class HPhi: public HValue {
     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();
 
@@ -3119,8 +3120,8 @@ class HPhi: public HValue {
   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;
   }
 
@@ -3134,25 +3135,31 @@ class HPhi: public HValue {
   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;
   }
 
@@ -3160,11 +3167,11 @@ class HDematerializedObject: public HTemplateInstruction<0> {
   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);
@@ -3191,7 +3198,7 @@ class HArgumentsObject: public HDematerializedObject {
 };
 
 
-class HCapturedObject: public HDematerializedObject {
+class HCapturedObject V8_FINAL : public HDematerializedObject {
  public:
   HCapturedObject(int length, Zone* zone)
       : HDematerializedObject(length, zone) {
@@ -3209,7 +3216,7 @@ class HCapturedObject: public HDematerializedObject {
 };
 
 
-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);
@@ -3276,11 +3283,11 @@ class HConstant: public HTemplateInstruction<0> {
     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();
@@ -3288,8 +3295,8 @@ class HConstant: public HTemplateInstruction<0> {
     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);
@@ -3346,7 +3353,7 @@ class HConstant: public HTemplateInstruction<0> {
   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_) {
@@ -3359,7 +3366,7 @@ class HConstant: public HTemplateInstruction<0> {
     }
   }
 
-  virtual void FinalizeUniqueValueId() {
+  virtual void FinalizeUniqueValueId() V8_OVERRIDE {
     if (!has_double_value_ && !has_external_reference_value_) {
       ASSERT(!handle_.is_null());
       unique_id_ = UniqueValueId(handle_);
@@ -3372,15 +3379,15 @@ class HConstant: public HTemplateInstruction<0> {
   }
 
 #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_ &&
@@ -3423,7 +3430,7 @@ class HConstant: public HTemplateInstruction<0> {
 
   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
@@ -3451,7 +3458,7 @@ class HConstant: public HTemplateInstruction<0> {
 };
 
 
-class HBinaryOperation: public HTemplateInstruction<3> {
+class HBinaryOperation : public HTemplateInstruction<3> {
  public:
   HBinaryOperation(HValue* context, HValue* left, HValue* right,
                    HType type = HType::Tagged())
@@ -3501,29 +3508,30 @@ class HBinaryOperation: public HTemplateInstruction<3> {
     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();
   }
@@ -3538,20 +3546,20 @@ class HBinaryOperation: public HTemplateInstruction<3> {
 };
 
 
-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)
 
@@ -3564,7 +3572,7 @@ class HWrapReceiver: public HTemplateInstruction<2> {
 };
 
 
-class HApplyArguments: public HTemplateInstruction<4> {
+class HApplyArguments V8_FINAL : public HTemplateInstruction<4> {
  public:
   HApplyArguments(HValue* function,
                   HValue* receiver,
@@ -3578,7 +3586,7 @@ class HApplyArguments: public HTemplateInstruction<4> {
     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()
@@ -3594,20 +3602,20 @@ class HApplyArguments: public HTemplateInstruction<4> {
 };
 
 
-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) {
@@ -3617,24 +3625,24 @@ class HArgumentsElements: public HTemplateInstruction<0> {
     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) {
@@ -3642,11 +3650,11 @@ class HArgumentsLength: public HUnaryOperation {
     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());
@@ -3656,9 +3664,9 @@ class HAccessArgumentsAt: public HTemplateInstruction<3> {
     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()
@@ -3671,14 +3679,14 @@ class HAccessArgumentsAt: public HTemplateInstruction<3> {
 
   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*);
 
@@ -3707,27 +3715,30 @@ class HBoundsCheck: public HTemplateInstruction<2> {
     }
   }
 
-  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_;
@@ -3749,13 +3760,14 @@ class HBoundsCheck: public HTemplateInstruction<2> {
     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;
@@ -3772,18 +3784,18 @@ class HBoundsCheckBaseIndexInformation: public HTemplateInstruction<2> {
 
   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())
@@ -3794,7 +3806,7 @@ class HBitwiseBinaryOperation: public HBinaryOperation {
     SetAllSideEffects();
   }
 
-  virtual void RepresentationChanged(Representation to) {
+  virtual void RepresentationChanged(Representation to) V8_OVERRIDE {
     if (!to.IsTagged()) {
       ASSERT(to.IsSmiOrInteger32());
       ClearAllSideEffects();
@@ -3807,13 +3819,13 @@ class HBitwiseBinaryOperation: public HBinaryOperation {
 
   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;
@@ -3827,11 +3839,11 @@ class HBitwiseBinaryOperation: public HBinaryOperation {
   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,
@@ -3840,12 +3852,13 @@ class HMathFloorOfDiv: public HBinaryOperation {
     return new(zone) HMathFloorOfDiv(context, left, right);
   }
 
-  virtual HValue* EnsureAndPropagateNotMinusZero(BitVector* visited);
+  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)
@@ -3859,11 +3872,11 @@ class HMathFloorOfDiv: public HBinaryOperation {
     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()) {
@@ -3872,7 +3885,7 @@ class HArithmeticBinaryOperation: public HBinaryOperation {
     SetFlag(kAllowUndefinedAsNaN);
   }
 
-  virtual void RepresentationChanged(Representation to) {
+  virtual void RepresentationChanged(Representation to) V8_OVERRIDE {
     if (to.IsTagged()) {
       SetAllSideEffects();
       ClearFlag(kUseGVN);
@@ -3885,11 +3898,11 @@ class HArithmeticBinaryOperation: public HBinaryOperation {
   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,
@@ -3902,14 +3915,14 @@ class HCompareGeneric: public HBinaryOperation {
     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)
 
@@ -3918,7 +3931,7 @@ class HCompareGeneric: public HBinaryOperation {
 };
 
 
-class HCompareNumericAndBranch: public HTemplateControlInstruction<2, 2> {
+class HCompareNumericAndBranch : public HTemplateControlInstruction<2, 2> {
  public:
   HCompareNumericAndBranch(HValue* left, HValue* right, Token::Value token)
       : token_(token) {
@@ -3938,15 +3951,16 @@ class HCompareNumericAndBranch: public HTemplateControlInstruction<2, 2> {
       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)
 
@@ -3956,7 +3970,8 @@ class HCompareNumericAndBranch: public HTemplateControlInstruction<2, 2> {
 };
 
 
-class HCompareHoleAndBranch: public HTemplateControlInstruction<2, 1> {
+class HCompareHoleAndBranch V8_FINAL
+    : public HTemplateControlInstruction<2, 1> {
  public:
   // TODO(danno): make this private when the IfBuilder properly constructs
   // control flow instructions.
@@ -3970,19 +3985,20 @@ class HCompareHoleAndBranch: public HTemplateControlInstruction<2, 1> {
 
   HValue* object() { return OperandAt(0); }
 
-  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 void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
   DECLARE_CONCRETE_INSTRUCTION(CompareHoleAndBranch)
 };
 
 
-class HCompareObjectEqAndBranch: public HTemplateControlInstruction<2, 2> {
+class HCompareObjectEqAndBranch : public HTemplateControlInstruction<2, 2> {
  public:
   // TODO(danno): make this private when the IfBuilder properly constructs
   // control flow instructions.
@@ -3997,13 +4013,13 @@ class HCompareObjectEqAndBranch: public HTemplateControlInstruction<2, 2> {
   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();
   }
 
@@ -4011,24 +4027,24 @@ class HCompareObjectEqAndBranch: public HTemplateControlInstruction<2, 2> {
 };
 
 
-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();
   }
 
@@ -4036,28 +4052,28 @@ class HIsStringAndBranch: public HUnaryControlInstruction {
 };
 
 
-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();
   }
 
@@ -4065,7 +4081,7 @@ class HIsUndetectableAndBranch: public HUnaryControlInstruction {
 };
 
 
-class HStringCompareAndBranch: public HTemplateControlInstruction<2, 3> {
+class HStringCompareAndBranch : public HTemplateControlInstruction<2, 3> {
  public:
   HStringCompareAndBranch(HValue* context,
                            HValue* left,
@@ -4085,9 +4101,9 @@ class HStringCompareAndBranch: public HTemplateControlInstruction<2, 3> {
   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();
   }
 
@@ -4102,9 +4118,9 @@ class HStringCompareAndBranch: public HTemplateControlInstruction<2, 3> {
 };
 
 
-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();
   }
 
@@ -4112,7 +4128,7 @@ class HIsConstructCallAndBranch: public HTemplateControlInstruction<2, 0> {
 };
 
 
-class HHasInstanceTypeAndBranch: public HUnaryControlInstruction {
+class HHasInstanceTypeAndBranch V8_FINAL : public HUnaryControlInstruction {
  public:
   HHasInstanceTypeAndBranch(HValue* value, InstanceType type)
       : HUnaryControlInstruction(value, NULL, NULL), from_(type), to_(type) { }
@@ -4124,9 +4140,9 @@ class HHasInstanceTypeAndBranch: public HUnaryControlInstruction {
   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();
   }
 
@@ -4138,12 +4154,12 @@ class HHasInstanceTypeAndBranch: public HUnaryControlInstruction {
 };
 
 
-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();
   }
 
@@ -4151,28 +4167,28 @@ class HHasCachedArrayIndexAndBranch: public HUnaryControlInstruction {
 };
 
 
-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),
@@ -4180,11 +4196,11 @@ class HClassOfTestAndBranch: public HUnaryControlInstruction {
 
   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_; }
 
@@ -4193,18 +4209,18 @@ class HClassOfTestAndBranch: public HUnaryControlInstruction {
 };
 
 
-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();
   }
 
@@ -4213,7 +4229,7 @@ class HTypeofIsAndBranch: public HUnaryControlInstruction {
 };
 
 
-class HInstanceOf: public HBinaryOperation {
+class HInstanceOf V8_FINAL : public HBinaryOperation {
  public:
   HInstanceOf(HValue* context, HValue* left, HValue* right)
       : HBinaryOperation(context, left, right, HType::Boolean()) {
@@ -4221,17 +4237,17 @@ class HInstanceOf: public HBinaryOperation {
     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,
@@ -4247,7 +4263,7 @@ class HInstanceOfKnownGlobal: public HTemplateInstruction<2> {
   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();
   }
 
@@ -4261,7 +4277,7 @@ class HInstanceOfKnownGlobal: public HTemplateInstruction<2> {
 // 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);
@@ -4270,7 +4286,7 @@ class HInstanceSize: public HTemplateInstruction<1> {
 
   HValue* object() { return OperandAt(0); }
 
-  virtual Representation RequiredInputRepresentation(int index) {
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     return Representation::Tagged();
   }
 
@@ -4278,7 +4294,7 @@ class HInstanceSize: public HTemplateInstruction<1> {
 };
 
 
-class HPower: public HTemplateInstruction<2> {
+class HPower V8_FINAL : public HTemplateInstruction<2> {
  public:
   static HInstruction* New(Zone* zone,
                            HValue* context,
@@ -4288,19 +4304,19 @@ class HPower: public HTemplateInstruction<2> {
   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) {
@@ -4311,13 +4327,13 @@ class HPower: public HTemplateInstruction<2> {
     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);
@@ -4326,18 +4342,18 @@ class HRandom: public HTemplateInstruction<1> {
 
   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,
@@ -4346,15 +4362,16 @@ class HAdd: public HArithmeticBinaryOperation {
 
   // 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;
@@ -4366,7 +4383,7 @@ class HAdd: public HArithmeticBinaryOperation {
     }
   }
 
-  virtual void RepresentationChanged(Representation to) {
+  virtual void RepresentationChanged(Representation to) V8_OVERRIDE {
     if (to.IsTagged()) ClearFlag(kAllowUndefinedAsNaN);
     HArithmeticBinaryOperation::RepresentationChanged(to);
   }
@@ -4374,9 +4391,9 @@ class HAdd: public HArithmeticBinaryOperation {
   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)
@@ -4386,18 +4403,19 @@ class HAdd: public HArithmeticBinaryOperation {
 };
 
 
-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;
@@ -4409,9 +4427,9 @@ class HSub: public HArithmeticBinaryOperation {
   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)
@@ -4421,7 +4439,7 @@ class HSub: public HArithmeticBinaryOperation {
 };
 
 
-class HMul: public HArithmeticBinaryOperation {
+class HMul V8_FINAL : public HArithmeticBinaryOperation {
  public:
   static HInstruction* New(Zone* zone,
                            HValue* context,
@@ -4439,18 +4457,19 @@ class HMul: public HArithmeticBinaryOperation {
     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);
   }
@@ -4458,9 +4477,9 @@ class HMul: public HArithmeticBinaryOperation {
   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)
@@ -4470,7 +4489,7 @@ class HMul: public HArithmeticBinaryOperation {
 };
 
 
-class HMod: public HArithmeticBinaryOperation {
+class HMod V8_FINAL : public HArithmeticBinaryOperation {
  public:
   static HInstruction* New(Zone* zone,
                            HValue* context,
@@ -4490,13 +4509,14 @@ class HMod: public HArithmeticBinaryOperation {
     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);
   }
@@ -4504,9 +4524,9 @@ class HMod: public HArithmeticBinaryOperation {
   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,
@@ -4523,7 +4543,7 @@ class HMod: public HArithmeticBinaryOperation {
 };
 
 
-class HDiv: public HArithmeticBinaryOperation {
+class HDiv V8_FINAL : public HArithmeticBinaryOperation {
  public:
   static HInstruction* New(Zone* zone,
                            HValue* context,
@@ -4539,13 +4559,14 @@ class HDiv: public HArithmeticBinaryOperation {
     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);
   }
@@ -4553,9 +4574,9 @@ class HDiv: public HArithmeticBinaryOperation {
   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)
@@ -4566,7 +4587,7 @@ class HDiv: public HArithmeticBinaryOperation {
 };
 
 
-class HMathMinMax: public HArithmeticBinaryOperation {
+class HMathMinMax V8_FINAL : public HArithmeticBinaryOperation {
  public:
   enum Operation { kMathMin, kMathMax };
 
@@ -4576,18 +4597,14 @@ class HMathMinMax: public HArithmeticBinaryOperation {
                            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();
@@ -4597,19 +4614,19 @@ class HMathMinMax: public HArithmeticBinaryOperation {
     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)
@@ -4620,7 +4637,7 @@ class HMathMinMax: public HArithmeticBinaryOperation {
 };
 
 
-class HBitwise: public HBitwiseBinaryOperation {
+class HBitwise V8_FINAL : public HBitwiseBinaryOperation {
  public:
   static HInstruction* New(Zone* zone,
                            HValue* context,
@@ -4630,20 +4647,20 @@ class HBitwise: public HBitwiseBinaryOperation {
 
   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,
@@ -4680,18 +4697,18 @@ class HBitwise: public HBitwiseBinaryOperation {
 };
 
 
-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)) {
@@ -4703,7 +4720,7 @@ class HShl: public HBitwiseBinaryOperation {
   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)
@@ -4711,14 +4728,14 @@ class HShl: public HBitwiseBinaryOperation {
 };
 
 
-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
@@ -4730,11 +4747,11 @@ class HShr: public HBitwiseBinaryOperation {
     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);
   }
@@ -4742,7 +4759,7 @@ class HShr: public HBitwiseBinaryOperation {
   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)
@@ -4750,14 +4767,14 @@ class HShr: public HBitwiseBinaryOperation {
 };
 
 
-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
@@ -4769,11 +4786,11 @@ class HSar: public HBitwiseBinaryOperation {
     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);
   }
@@ -4781,7 +4798,7 @@ class HSar: public HBitwiseBinaryOperation {
   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)
@@ -4789,7 +4806,7 @@ class HSar: public HBitwiseBinaryOperation {
 };
 
 
-class HRor: public HBitwiseBinaryOperation {
+class HRor V8_FINAL : public HBitwiseBinaryOperation {
  public:
   HRor(HValue* context, HValue* left, HValue* right)
        : HBitwiseBinaryOperation(context, left, right) {
@@ -4798,7 +4815,7 @@ class HRor: public HBitwiseBinaryOperation {
 
   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);
   }
@@ -4806,17 +4823,17 @@ class HRor: public HBitwiseBinaryOperation {
   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();
   }
 
@@ -4832,7 +4849,7 @@ class HOsrEntry: public HTemplateInstruction<0> {
 };
 
 
-class HParameter: public HTemplateInstruction<0> {
+class HParameter V8_FINAL : public HTemplateInstruction<0> {
  public:
   enum ParameterKind {
     STACK_PARAMETER,
@@ -4847,9 +4864,9 @@ class HParameter: public HTemplateInstruction<0> {
   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();
   }
 
@@ -4876,7 +4893,7 @@ class HParameter: public HTemplateInstruction<0> {
 };
 
 
-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),
@@ -4895,11 +4912,7 @@ class HCallStub: public HUnaryCall {
     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)
 
@@ -4909,11 +4922,11 @@ class HCallStub: public HUnaryCall {
 };
 
 
-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();
   }
 
@@ -4925,7 +4938,7 @@ class HUnknownOSRValue: public HTemplateInstruction<0> {
     return incoming_value_;
   }
 
-  virtual Representation KnownOptimalRepresentation() {
+  virtual Representation KnownOptimalRepresentation() V8_OVERRIDE {
     if (incoming_value_ == NULL) return Representation::None();
     return incoming_value_->KnownOptimalRepresentation();
   }
@@ -4942,7 +4955,7 @@ class HUnknownOSRValue: public HTemplateInstruction<0> {
 };
 
 
-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_() {
@@ -4954,30 +4967,30 @@ class HLoadGlobalCell: public HTemplateInstruction<0> {
   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_;
@@ -4985,7 +4998,7 @@ class HLoadGlobalCell: public HTemplateInstruction<0> {
 };
 
 
-class HLoadGlobalGeneric: public HTemplateInstruction<2> {
+class HLoadGlobalGeneric V8_FINAL : public HTemplateInstruction<2> {
  public:
   HLoadGlobalGeneric(HValue* context,
                      HValue* global_object,
@@ -5004,9 +5017,9 @@ class HLoadGlobalGeneric: public HTemplateInstruction<2> {
   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();
   }
 
@@ -5018,7 +5031,7 @@ class HLoadGlobalGeneric: public HTemplateInstruction<2> {
 };
 
 
-class HAllocate: public HTemplateInstruction<2> {
+class HAllocate V8_FINAL : public HTemplateInstruction<2> {
  public:
   static HAllocate* New(Zone* zone,
                         HValue* context,
@@ -5036,7 +5049,7 @@ class HAllocate: public HTemplateInstruction<2> {
   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 {
@@ -5085,9 +5098,9 @@ class HAllocate: public HTemplateInstruction<2> {
   }
 
   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)
 
@@ -5127,7 +5140,7 @@ class HAllocate: public HTemplateInstruction<2> {
 };
 
 
-class HInnerAllocatedObject: public HTemplateInstruction<1> {
+class HInnerAllocatedObject V8_FINAL : public HTemplateInstruction<1> {
  public:
   static HInnerAllocatedObject* New(Zone* zone,
                                     HValue* context,
@@ -5140,11 +5153,11 @@ class HInnerAllocatedObject: public HTemplateInstruction<1> {
   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)
 
@@ -5191,7 +5204,7 @@ inline bool ReceiverObjectNeedsWriteBarrier(HValue* object,
 }
 
 
-class HStoreGlobalCell: public HUnaryOperation {
+class HStoreGlobalCell V8_FINAL : public HUnaryOperation {
  public:
   DECLARE_INSTRUCTION_FACTORY_P3(HStoreGlobalCell, HValue*,
                                  Handle<PropertyCell>, PropertyDetails);
@@ -5204,10 +5217,10 @@ class HStoreGlobalCell: public HUnaryOperation {
     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)
 
@@ -5226,7 +5239,7 @@ class HStoreGlobalCell: public HUnaryOperation {
 };
 
 
-class HStoreGlobalGeneric: public HTemplateInstruction<3> {
+class HStoreGlobalGeneric : public HTemplateInstruction<3> {
  public:
   inline static HStoreGlobalGeneric* New(Zone* zone,
                                          HValue* context,
@@ -5244,9 +5257,9 @@ class HStoreGlobalGeneric: public HTemplateInstruction<3> {
   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();
   }
 
@@ -5272,7 +5285,7 @@ class HStoreGlobalGeneric: public HTemplateInstruction<3> {
 };
 
 
-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.
@@ -5317,29 +5330,29 @@ class HLoadContextSlot: public HUnaryOperation {
     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
@@ -5374,11 +5387,11 @@ class HStoreContextSlot: public HTemplateInstruction<2> {
     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)
 
@@ -5397,7 +5410,7 @@ class HStoreContextSlot: public HTemplateInstruction<2> {
 
 // 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;
@@ -5572,7 +5585,7 @@ class HObjectAccess {
 };
 
 
-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,
@@ -5591,21 +5604,21 @@ class HLoadNamedField: public HTemplateInstruction<2> {
       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_);
   }
@@ -5637,13 +5650,13 @@ class HLoadNamedField: public HTemplateInstruction<2> {
     access.SetGVNFlags(this, false);
   }
 
-  virtual bool IsDeletable() const { return true; }
+  virtual bool IsDeletable() const V8_OVERRIDE { return true; }
 
   HObjectAccess access_;
 };
 
 
-class HLoadNamedGeneric: public HTemplateInstruction<2> {
+class HLoadNamedGeneric V8_FINAL : public HTemplateInstruction<2> {
  public:
   HLoadNamedGeneric(HValue* context, HValue* object, Handle<Object> name)
       : name_(name) {
@@ -5657,11 +5670,11 @@ class HLoadNamedGeneric: public HTemplateInstruction<2> {
   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)
 
@@ -5670,7 +5683,7 @@ class HLoadNamedGeneric: public HTemplateInstruction<2> {
 };
 
 
-class HLoadFunctionPrototype: public HUnaryOperation {
+class HLoadFunctionPrototype V8_FINAL : public HUnaryOperation {
  public:
   explicit HLoadFunctionPrototype(HValue* function)
       : HUnaryOperation(function) {
@@ -5681,14 +5694,14 @@ class HLoadFunctionPrototype: public HUnaryOperation {
 
   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 {
@@ -5713,7 +5726,7 @@ enum LoadKeyedHoleMode {
 };
 
 
-class HLoadKeyed
+class HLoadKeyed V8_FINAL
     : public HTemplateInstruction<3>, public ArrayInstructionInterface {
  public:
   DECLARE_INSTRUCTION_FACTORY_P4(HLoadKeyed, HValue*, HValue*, HValue*,
@@ -5748,7 +5761,7 @@ class HLoadKeyed
     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)
@@ -5763,22 +5776,22 @@ class HLoadKeyed
     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);
 
@@ -5838,7 +5851,7 @@ class HLoadKeyed
     SetFlag(kUseGVN);
   }
 
-  virtual bool IsDeletable() const {
+  virtual bool IsDeletable() const V8_OVERRIDE {
     return !RequiresHoleCheck();
   }
 
@@ -5874,7 +5887,7 @@ class HLoadKeyed
 };
 
 
-class HLoadKeyedGeneric: public HTemplateInstruction<3> {
+class HLoadKeyedGeneric V8_FINAL : public HTemplateInstruction<3> {
  public:
   HLoadKeyedGeneric(HValue* context, HValue* obj, HValue* key) {
     set_representation(Representation::Tagged());
@@ -5888,28 +5901,30 @@ class HLoadKeyedGeneric: public HTemplateInstruction<3> {
   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();
@@ -5922,11 +5937,11 @@ class HStoreNamedField: public HTemplateInstruction<3> {
     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 {
@@ -6001,7 +6016,7 @@ class HStoreNamedField: public HTemplateInstruction<3> {
 };
 
 
-class HStoreNamedGeneric: public HTemplateInstruction<3> {
+class HStoreNamedGeneric V8_FINAL : public HTemplateInstruction<3> {
  public:
   HStoreNamedGeneric(HValue* context,
                      HValue* object,
@@ -6022,9 +6037,9 @@ class HStoreNamedGeneric: public HTemplateInstruction<3> {
   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();
   }
 
@@ -6036,13 +6051,13 @@ class HStoreNamedGeneric: public HTemplateInstruction<3> {
 };
 
 
-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
@@ -6072,7 +6087,7 @@ class HStoreKeyed
     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();
@@ -6113,7 +6128,7 @@ class HStoreKeyed
   }
 
   virtual void HandleSideEffectDominator(GVNFlag side_effect,
-                                         HValue* dominator) {
+                                         HValue* dominator) V8_OVERRIDE {
     ASSERT(side_effect == kChangesNewSpacePromotion);
     new_space_dominator_ = dominator;
   }
@@ -6131,7 +6146,7 @@ class HStoreKeyed
 
   bool NeedsCanonicalization();
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
   DECLARE_CONCRETE_INSTRUCTION(StoreKeyed)
 
@@ -6177,7 +6192,7 @@ class HStoreKeyed
 };
 
 
-class HStoreKeyedGeneric: public HTemplateInstruction<4> {
+class HStoreKeyedGeneric V8_FINAL : public HTemplateInstruction<4> {
  public:
   HStoreKeyedGeneric(HValue* context,
                      HValue* object,
@@ -6198,12 +6213,12 @@ class HStoreKeyedGeneric: public HTemplateInstruction<4> {
   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)
 
@@ -6212,7 +6227,7 @@ class HStoreKeyedGeneric: public HTemplateInstruction<4> {
 };
 
 
-class HTransitionElementsKind: public HTemplateInstruction<2> {
+class HTransitionElementsKind V8_FINAL : public HTemplateInstruction<2> {
  public:
   inline static HTransitionElementsKind* New(Zone* zone,
                                              HValue* context,
@@ -6223,7 +6238,7 @@ class HTransitionElementsKind: public HTemplateInstruction<2> {
                                              original_map, transitioned_map);
   }
 
-  virtual Representation RequiredInputRepresentation(int index) {
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     return Representation::Tagged();
   }
 
@@ -6234,9 +6249,9 @@ class HTransitionElementsKind: public HTemplateInstruction<2> {
   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_);
   }
@@ -6244,7 +6259,7 @@ class HTransitionElementsKind: public HTemplateInstruction<2> {
   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_;
@@ -6281,7 +6296,7 @@ class HTransitionElementsKind: public HTemplateInstruction<2> {
 };
 
 
-class HStringAdd: public HBinaryOperation {
+class HStringAdd V8_FINAL : public HBinaryOperation {
  public:
   static HInstruction* New(Zone* zone,
                            HValue* context,
@@ -6291,14 +6306,14 @@ class HStringAdd: public HBinaryOperation {
 
   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)
@@ -6311,13 +6326,13 @@ class HStringAdd: public HBinaryOperation {
 
   // 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,
@@ -6340,9 +6355,9 @@ class HStringCharCodeAt: public HTemplateInstruction<3> {
   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);
   }
 
@@ -6358,17 +6373,17 @@ class HStringCharCodeAt: public HTemplateInstruction<3> {
   }
 
   // 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();
@@ -6377,7 +6392,7 @@ class HStringCharFromCode: public HTemplateInstruction<2> {
   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)
 
@@ -6391,14 +6406,14 @@ class HStringCharFromCode: public HTemplateInstruction<2> {
     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) {
@@ -6418,7 +6433,7 @@ class HMaterializedLiteral: public HTemplateInstruction<V> {
   }
 
  private:
-  virtual bool IsDeletable() const { return true; }
+  virtual bool IsDeletable() const V8_FINAL V8_OVERRIDE { return true; }
 
   int literal_index_;
   int depth_;
@@ -6426,7 +6441,7 @@ class HMaterializedLiteral: public HTemplateInstruction<V> {
 };
 
 
-class HRegExpLiteral: public HMaterializedLiteral<1> {
+class HRegExpLiteral V8_FINAL : public HMaterializedLiteral<1> {
  public:
   HRegExpLiteral(HValue* context,
                  Handle<FixedArray> literals,
@@ -6447,7 +6462,7 @@ class HRegExpLiteral: public HMaterializedLiteral<1> {
   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();
   }
 
@@ -6460,7 +6475,7 @@ class HRegExpLiteral: public HMaterializedLiteral<1> {
 };
 
 
-class HFunctionLiteral: public HTemplateInstruction<1> {
+class HFunctionLiteral V8_FINAL : public HTemplateInstruction<1> {
  public:
   HFunctionLiteral(HValue* context,
                    Handle<SharedFunctionInfo> shared,
@@ -6478,7 +6493,7 @@ class HFunctionLiteral: public HTemplateInstruction<1> {
 
   HValue* context() { return OperandAt(0); }
 
-  virtual Representation RequiredInputRepresentation(int index) {
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     return Representation::Tagged();
   }
 
@@ -6491,7 +6506,7 @@ class HFunctionLiteral: public HTemplateInstruction<1> {
   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;
@@ -6501,7 +6516,7 @@ class HFunctionLiteral: public HTemplateInstruction<1> {
 };
 
 
-class HTypeof: public HTemplateInstruction<2> {
+class HTypeof V8_FINAL : public HTemplateInstruction<2> {
  public:
   explicit HTypeof(HValue* context, HValue* value) {
     SetOperandAt(0, context);
@@ -6512,24 +6527,24 @@ class HTypeof: public HTemplateInstruction<2> {
   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();
   }
 
@@ -6544,11 +6559,11 @@ class HTrapAllocationMemento : public HTemplateInstruction<1> {
 };
 
 
-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();
   }
 
@@ -6570,28 +6585,28 @@ class HToFastProperties: public HUnaryOperation {
 #endif
   }
 
-  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) {
@@ -6600,7 +6615,7 @@ class HDateField: public HUnaryOperation {
 
   Smi* index() const { return index_; }
 
-  virtual Representation RequiredInputRepresentation(int index) {
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     return Representation::Tagged();
   }
 
@@ -6611,7 +6626,7 @@ class HDateField: public HUnaryOperation {
 };
 
 
-class HSeqStringSetChar: public HTemplateInstruction<3> {
+class HSeqStringSetChar V8_FINAL : public HTemplateInstruction<3> {
  public:
   HSeqStringSetChar(String::Encoding encoding,
                     HValue* string,
@@ -6628,7 +6643,7 @@ class HSeqStringSetChar: public HTemplateInstruction<3> {
   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();
   }
@@ -6640,17 +6655,17 @@ class HSeqStringSetChar: public HTemplateInstruction<3> {
 };
 
 
-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();
   }
 
@@ -6660,7 +6675,7 @@ class HCheckMapValue: public HTemplateInstruction<2> {
   DECLARE_CONCRETE_INSTRUCTION(CheckMapValue)
 
  protected:
-  virtual bool DataEquals(HValue* other) {
+  virtual bool DataEquals(HValue* other) V8_OVERRIDE {
     return true;
   }
 
@@ -6677,7 +6692,7 @@ class HCheckMapValue: public HTemplateInstruction<2> {
 };
 
 
-class HForInPrepareMap : public HTemplateInstruction<2> {
+class HForInPrepareMap V8_FINAL : public HTemplateInstruction<2> {
  public:
   static HForInPrepareMap* New(Zone* zone,
                                HValue* context,
@@ -6685,16 +6700,16 @@ class HForInPrepareMap : public HTemplateInstruction<2> {
     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();
   }
 
@@ -6711,11 +6726,11 @@ class HForInPrepareMap : public HTemplateInstruction<2> {
 };
 
 
-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();
   }
 
@@ -6731,9 +6746,9 @@ class HForInCacheArray : public HTemplateInstruction<2> {
     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();
   }
 
@@ -6753,7 +6768,7 @@ class HForInCacheArray : public HTemplateInstruction<2> {
 };
 
 
-class HLoadFieldByIndex : public HTemplateInstruction<2> {
+class HLoadFieldByIndex V8_FINAL : public HTemplateInstruction<2> {
  public:
   HLoadFieldByIndex(HValue* object,
                     HValue* index) {
@@ -6762,23 +6777,23 @@ class HLoadFieldByIndex : public HTemplateInstruction<2> {
     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; }
 };
 
 
diff --git a/src/hydrogen.cc b/src/hydrogen.cc
index ba1de7aa22..9abca53821 100644
--- a/src/hydrogen.cc
+++ b/src/hydrogen.cc
@@ -7279,7 +7279,7 @@ void HOptimizedGraphBuilder::VisitCallNew(CallNew* expr) {
     CHECK_ALIVE(VisitArgument(expr->expression()));
     HValue* constructor = HPushArgument::cast(Top())->argument();
     CHECK_ALIVE(VisitArgumentList(expr->arguments()));
-    HCallNew* call;
+    HBinaryCall* call;
     if (expr->target().is_identical_to(array_function)) {
       Handle<Cell> cell = expr->allocation_info_cell();
       Add<HCheckFunction>(constructor, array_function);
diff --git a/src/hydrogen.h b/src/hydrogen.h
index 004aa16a87..af31b60a5b 100644
--- a/src/hydrogen.h
+++ b/src/hydrogen.h
@@ -53,10 +53,10 @@ class LChunk;
 class LiveRange;
 
 
-class HBasicBlock: public ZoneObject {
+class HBasicBlock V8_FINAL : public ZoneObject {
  public:
   explicit HBasicBlock(HGraph* graph);
-  virtual ~HBasicBlock() { }
+  ~HBasicBlock() { }
 
   // Simple accessors.
   int block_id() const { return block_id_; }
@@ -220,7 +220,7 @@ class HBasicBlock: public ZoneObject {
 };
 
 
-class HPredecessorIterator BASE_EMBEDDED {
+class HPredecessorIterator V8_FINAL BASE_EMBEDDED {
  public:
   explicit HPredecessorIterator(HBasicBlock* block)
       : predecessor_list_(block->predecessors()), current_(0) { }
@@ -235,7 +235,7 @@ class HPredecessorIterator BASE_EMBEDDED {
 };
 
 
-class HInstructionIterator BASE_EMBEDDED {
+class HInstructionIterator V8_FINAL BASE_EMBEDDED {
  public:
   explicit HInstructionIterator(HBasicBlock* block)
       : instr_(block->first()) {
@@ -255,7 +255,7 @@ class HInstructionIterator BASE_EMBEDDED {
 };
 
 
-class HLoopInformation: public ZoneObject {
+class HLoopInformation V8_FINAL : public ZoneObject {
  public:
   HLoopInformation(HBasicBlock* loop_header, Zone* zone)
       : back_edges_(4, zone),
@@ -264,7 +264,7 @@ class HLoopInformation: public ZoneObject {
         stack_check_(NULL) {
     blocks_.Add(loop_header, zone);
   }
-  virtual ~HLoopInformation() {}
+  ~HLoopInformation() {}
 
   const ZoneList<HBasicBlock*>* back_edges() const { return &back_edges_; }
   const ZoneList<HBasicBlock*>* blocks() const { return &blocks_; }
@@ -303,7 +303,7 @@ class HLoopInformation: public ZoneObject {
 
 class BoundsCheckTable;
 class InductionVariableBlocksTable;
-class HGraph: public ZoneObject {
+class HGraph V8_FINAL : public ZoneObject {
  public:
   explicit HGraph(CompilationInfo* info);
 
@@ -523,7 +523,7 @@ enum FrameType {
 };
 
 
-class HEnvironment: public ZoneObject {
+class HEnvironment V8_FINAL : public ZoneObject {
  public:
   HEnvironment(HEnvironment* outer,
                Scope* scope,
@@ -793,33 +793,37 @@ class AstContext {
 };
 
 
-class EffectContext: public AstContext {
+class EffectContext V8_FINAL : public AstContext {
  public:
   explicit EffectContext(HOptimizedGraphBuilder* owner)
       : AstContext(owner, Expression::kEffect) {
   }
   virtual ~EffectContext();
 
-  virtual void ReturnValue(HValue* value);
-  virtual void ReturnInstruction(HInstruction* instr, BailoutId ast_id);
-  virtual void ReturnControl(HControlInstruction* instr, BailoutId ast_id);
+  virtual void ReturnValue(HValue* value) V8_OVERRIDE;
+  virtual void ReturnInstruction(HInstruction* instr,
+                                 BailoutId ast_id) V8_OVERRIDE;
+  virtual void ReturnControl(HControlInstruction* instr,
+                             BailoutId ast_id) V8_OVERRIDE;
   virtual void ReturnContinuation(HIfContinuation* continuation,
-                                  BailoutId ast_id);
+                                  BailoutId ast_id) V8_OVERRIDE;
 };
 
 
-class ValueContext: public AstContext {
+class ValueContext V8_FINAL : public AstContext {
  public:
   ValueContext(HOptimizedGraphBuilder* owner, ArgumentsAllowedFlag flag)
       : AstContext(owner, Expression::kValue), flag_(flag) {
   }
   virtual ~ValueContext();
 
-  virtual void ReturnValue(HValue* value);
-  virtual void ReturnInstruction(HInstruction* instr, BailoutId ast_id);
-  virtual void ReturnControl(HControlInstruction* instr, BailoutId ast_id);
+  virtual void ReturnValue(HValue* value) V8_OVERRIDE;
+  virtual void ReturnInstruction(HInstruction* instr,
+                                 BailoutId ast_id) V8_OVERRIDE;
+  virtual void ReturnControl(HControlInstruction* instr,
+                             BailoutId ast_id) V8_OVERRIDE;
   virtual void ReturnContinuation(HIfContinuation* continuation,
-                                  BailoutId ast_id);
+                                  BailoutId ast_id) V8_OVERRIDE;
 
   bool arguments_allowed() { return flag_ == ARGUMENTS_ALLOWED; }
 
@@ -828,7 +832,7 @@ class ValueContext: public AstContext {
 };
 
 
-class TestContext: public AstContext {
+class TestContext V8_FINAL : public AstContext {
  public:
   TestContext(HOptimizedGraphBuilder* owner,
               Expression* condition,
@@ -840,11 +844,13 @@ class TestContext: public AstContext {
         if_false_(if_false) {
   }
 
-  virtual void ReturnValue(HValue* value);
-  virtual void ReturnInstruction(HInstruction* instr, BailoutId ast_id);
-  virtual void ReturnControl(HControlInstruction* instr, BailoutId ast_id);
+  virtual void ReturnValue(HValue* value) V8_OVERRIDE;
+  virtual void ReturnInstruction(HInstruction* instr,
+                                 BailoutId ast_id) V8_OVERRIDE;
+  virtual void ReturnControl(HControlInstruction* instr,
+                             BailoutId ast_id) V8_OVERRIDE;
   virtual void ReturnContinuation(HIfContinuation* continuation,
-                                  BailoutId ast_id);
+                                  BailoutId ast_id) V8_OVERRIDE;
 
   static TestContext* cast(AstContext* context) {
     ASSERT(context->IsTest());
@@ -866,7 +872,7 @@ class TestContext: public AstContext {
 };
 
 
-class FunctionState {
+class FunctionState V8_FINAL {
  public:
   FunctionState(HOptimizedGraphBuilder* owner,
                 CompilationInfo* info,
@@ -933,7 +939,7 @@ class FunctionState {
 };
 
 
-class HIfContinuation {
+class HIfContinuation V8_FINAL {
  public:
   HIfContinuation() { continuation_captured_ = false; }
   ~HIfContinuation() { ASSERT(!continuation_captured_); }
@@ -1272,7 +1278,7 @@ class HGraphBuilder {
   void AddIncrementCounter(StatsCounter* counter,
                            HValue* context);
 
-  class IfBuilder {
+  class IfBuilder V8_FINAL {
    public:
     explicit IfBuilder(HGraphBuilder* builder,
                        int position = RelocInfo::kNoPosition);
@@ -1402,7 +1408,7 @@ class HGraphBuilder {
     HBasicBlock* merge_block_;
   };
 
-  class LoopBuilder {
+  class LoopBuilder V8_FINAL {
    public:
     enum Direction {
       kPreIncrement,
@@ -1443,7 +1449,7 @@ class HGraphBuilder {
   void BuildNewSpaceArrayCheck(HValue* length,
                                ElementsKind kind);
 
-  class JSArrayBuilder {
+  class JSArrayBuilder V8_FINAL {
    public:
     JSArrayBuilder(HGraphBuilder* builder,
                    ElementsKind kind,
@@ -1642,12 +1648,13 @@ inline HInstruction* HGraphBuilder::NewUncasted<HContext>() {
 }
 
 
-class HOptimizedGraphBuilder: public HGraphBuilder, public AstVisitor {
+class HOptimizedGraphBuilder V8_FINAL
+    : public HGraphBuilder, public AstVisitor {
  public:
   // A class encapsulating (lazily-allocated) break and continue blocks for
   // a breakable statement.  Separated from BreakAndContinueScope so that it
   // can have a separate lifetime.
-  class BreakAndContinueInfo BASE_EMBEDDED {
+  class BreakAndContinueInfo V8_FINAL BASE_EMBEDDED {
    public:
     explicit BreakAndContinueInfo(BreakableStatement* target,
                                   int drop_extra = 0)
@@ -1673,7 +1680,7 @@ class HOptimizedGraphBuilder: public HGraphBuilder, public AstVisitor {
 
   // A helper class to maintain a stack of current BreakAndContinueInfo
   // structures mirroring BreakableStatement nesting.
-  class BreakAndContinueScope BASE_EMBEDDED {
+  class BreakAndContinueScope V8_FINAL BASE_EMBEDDED {
    public:
     BreakAndContinueScope(BreakAndContinueInfo* info,
                           HOptimizedGraphBuilder* owner)
@@ -1699,7 +1706,7 @@ class HOptimizedGraphBuilder: public HGraphBuilder, public AstVisitor {
 
   explicit HOptimizedGraphBuilder(CompilationInfo* info);
 
-  virtual bool BuildGraph();
+  virtual bool BuildGraph() V8_OVERRIDE;
 
   // Simple accessors.
   BreakAndContinueScope* break_scope() const { return break_scope_; }
@@ -1885,9 +1892,9 @@ class HOptimizedGraphBuilder: public HGraphBuilder, public AstVisitor {
   template <class Instruction> HInstruction* PreProcessCall(Instruction* call);
 
   void SetUpScope(Scope* scope);
-  virtual void VisitStatements(ZoneList<Statement*>* statements);
+  virtual void VisitStatements(ZoneList<Statement*>* statements) V8_OVERRIDE;
 
-#define DECLARE_VISIT(type) virtual void Visit##type(type* node);
+#define DECLARE_VISIT(type) virtual void Visit##type(type* node) V8_OVERRIDE;
   AST_NODE_LIST(DECLARE_VISIT)
 #undef DECLARE_VISIT
 
@@ -2166,7 +2173,7 @@ class HOptimizedGraphBuilder: public HGraphBuilder, public AstVisitor {
 Zone* AstContext::zone() const { return owner_->zone(); }
 
 
-class HStatistics: public Malloced {
+class HStatistics V8_FINAL: public Malloced {
  public:
   HStatistics()
       : timing_(5),
@@ -2225,7 +2232,7 @@ class HPhase : public CompilationPhase {
 };
 
 
-class HTracer: public Malloced {
+class HTracer V8_FINAL : public Malloced {
  public:
   explicit HTracer(int isolate_id)
       : trace_(&string_allocator_), indent_(0) {
@@ -2246,7 +2253,7 @@ class HTracer: public Malloced {
   void TraceLiveRanges(const char* name, LAllocator* allocator);
 
  private:
-  class Tag BASE_EMBEDDED {
+  class Tag V8_FINAL BASE_EMBEDDED {
    public:
     Tag(HTracer* tracer, const char* name) {
       name_ = name;
@@ -2311,7 +2318,7 @@ class HTracer: public Malloced {
 };
 
 
-class NoObservableSideEffectsScope {
+class NoObservableSideEffectsScope V8_FINAL {
  public:
   explicit NoObservableSideEffectsScope(HGraphBuilder* builder) :
       builder_(builder) {
diff --git a/src/ia32/lithium-codegen-ia32.cc b/src/ia32/lithium-codegen-ia32.cc
index 19c553bfa5..6dc0171b00 100644
--- a/src/ia32/lithium-codegen-ia32.cc
+++ b/src/ia32/lithium-codegen-ia32.cc
@@ -48,7 +48,7 @@ static SaveFPRegsMode GetSaveFPRegsMode() {
 
 // When invoking builtins, we need to record the safepoint in the middle of
 // the invoke instruction sequence generated by the macro assembler.
-class SafepointGenerator : public CallWrapper {
+class SafepointGenerator V8_FINAL : public CallWrapper {
  public:
   SafepointGenerator(LCodeGen* codegen,
                      LPointerMap* pointers,
@@ -56,11 +56,11 @@ class SafepointGenerator : public CallWrapper {
       : codegen_(codegen),
         pointers_(pointers),
         deopt_mode_(mode) {}
-  virtual ~SafepointGenerator() { }
+  virtual ~SafepointGenerator() {}
 
-  virtual void BeforeCall(int call_size) const {}
+  virtual void BeforeCall(int call_size) const V8_OVERRIDE {}
 
-  virtual void AfterCall() const {
+  virtual void AfterCall() const V8_OVERRIDE {
     codegen_->RecordSafepoint(pointers_, deopt_mode_);
   }
 
@@ -2816,15 +2816,15 @@ void LCodeGen::DoInstanceOf(LInstanceOf* instr) {
 
 
 void LCodeGen::DoInstanceOfKnownGlobal(LInstanceOfKnownGlobal* instr) {
-  class DeferredInstanceOfKnownGlobal: public LDeferredCode {
+  class DeferredInstanceOfKnownGlobal V8_FINAL : public LDeferredCode {
    public:
     DeferredInstanceOfKnownGlobal(LCodeGen* codegen,
                                   LInstanceOfKnownGlobal* instr)
         : LDeferredCode(codegen), instr_(instr) { }
-    virtual void Generate() {
+    virtual void Generate() V8_OVERRIDE {
       codegen()->DoDeferredInstanceOfKnownGlobal(instr_, &map_check_);
     }
-    virtual LInstruction* instr() { return instr_; }
+    virtual LInstruction* instr() V8_OVERRIDE { return instr_; }
     Label* map_check() { return &map_check_; }
    private:
     LInstanceOfKnownGlobal* instr_;
@@ -3784,14 +3784,14 @@ void LCodeGen::EmitIntegerMathAbs(LMathAbs* instr) {
 
 void LCodeGen::DoMathAbs(LMathAbs* instr) {
   // Class for deferred case.
-  class DeferredMathAbsTaggedHeapNumber: public LDeferredCode {
+  class DeferredMathAbsTaggedHeapNumber V8_FINAL : public LDeferredCode {
    public:
     DeferredMathAbsTaggedHeapNumber(LCodeGen* codegen, LMathAbs* instr)
         : LDeferredCode(codegen), instr_(instr) { }
-    virtual void Generate() {
+    virtual void Generate() V8_OVERRIDE {
       codegen()->DoDeferredMathAbsTaggedHeapNumber(instr_);
     }
-    virtual LInstruction* instr() { return instr_; }
+    virtual LInstruction* instr() V8_OVERRIDE { return instr_; }
    private:
     LMathAbs* instr_;
   };
@@ -4024,12 +4024,12 @@ void LCodeGen::DoPower(LPower* instr) {
 
 
 void LCodeGen::DoRandom(LRandom* instr) {
-  class DeferredDoRandom: public LDeferredCode {
+  class DeferredDoRandom V8_FINAL : public LDeferredCode {
    public:
     DeferredDoRandom(LCodeGen* codegen, LRandom* instr)
         : LDeferredCode(codegen), instr_(instr) { }
-    virtual void Generate() { codegen()->DoDeferredRandom(instr_); }
-    virtual LInstruction* instr() { return instr_; }
+    virtual void Generate() V8_OVERRIDE { codegen()->DoDeferredRandom(instr_); }
+    virtual LInstruction* instr() V8_OVERRIDE { return instr_; }
    private:
     LRandom* instr_;
   };
@@ -4759,12 +4759,14 @@ void LCodeGen::DoTransitionElementsKind(LTransitionElementsKind* instr) {
 
 
 void LCodeGen::DoStringCharCodeAt(LStringCharCodeAt* instr) {
-  class DeferredStringCharCodeAt: public LDeferredCode {
+  class DeferredStringCharCodeAt V8_FINAL : public LDeferredCode {
    public:
     DeferredStringCharCodeAt(LCodeGen* codegen, LStringCharCodeAt* instr)
         : LDeferredCode(codegen), instr_(instr) { }
-    virtual void Generate() { codegen()->DoDeferredStringCharCodeAt(instr_); }
-    virtual LInstruction* instr() { return instr_; }
+    virtual void Generate() V8_OVERRIDE {
+      codegen()->DoDeferredStringCharCodeAt(instr_);
+    }
+    virtual LInstruction* instr() V8_OVERRIDE { return instr_; }
    private:
     LStringCharCodeAt* instr_;
   };
@@ -4814,12 +4816,14 @@ void LCodeGen::DoDeferredStringCharCodeAt(LStringCharCodeAt* instr) {
 
 
 void LCodeGen::DoStringCharFromCode(LStringCharFromCode* instr) {
-  class DeferredStringCharFromCode: public LDeferredCode {
+  class DeferredStringCharFromCode V8_FINAL : public LDeferredCode {
    public:
     DeferredStringCharFromCode(LCodeGen* codegen, LStringCharFromCode* instr)
         : LDeferredCode(codegen), instr_(instr) { }
-    virtual void Generate() { codegen()->DoDeferredStringCharFromCode(instr_); }
-    virtual LInstruction* instr() { return instr_; }
+    virtual void Generate() V8_OVERRIDE {
+      codegen()->DoDeferredStringCharFromCode(instr_);
+    }
+    virtual LInstruction* instr() V8_OVERRIDE { return instr_; }
    private:
     LStringCharFromCode* instr_;
   };
@@ -4906,14 +4910,14 @@ void LCodeGen::DoUint32ToDouble(LUint32ToDouble* instr) {
 
 
 void LCodeGen::DoNumberTagI(LNumberTagI* instr) {
-  class DeferredNumberTagI: public LDeferredCode {
+  class DeferredNumberTagI V8_FINAL : public LDeferredCode {
    public:
     DeferredNumberTagI(LCodeGen* codegen, LNumberTagI* instr)
         : LDeferredCode(codegen), instr_(instr) { }
-    virtual void Generate() {
+    virtual void Generate() V8_OVERRIDE {
       codegen()->DoDeferredNumberTagI(instr_, instr_->value(), SIGNED_INT32);
     }
-    virtual LInstruction* instr() { return instr_; }
+    virtual LInstruction* instr() V8_OVERRIDE { return instr_; }
    private:
     LNumberTagI* instr_;
   };
@@ -4930,14 +4934,14 @@ void LCodeGen::DoNumberTagI(LNumberTagI* instr) {
 
 
 void LCodeGen::DoNumberTagU(LNumberTagU* instr) {
-  class DeferredNumberTagU: public LDeferredCode {
+  class DeferredNumberTagU V8_FINAL : public LDeferredCode {
    public:
     DeferredNumberTagU(LCodeGen* codegen, LNumberTagU* instr)
         : LDeferredCode(codegen), instr_(instr) { }
-    virtual void Generate() {
+    virtual void Generate() V8_OVERRIDE {
       codegen()->DoDeferredNumberTagI(instr_, instr_->value(), UNSIGNED_INT32);
     }
-    virtual LInstruction* instr() { return instr_; }
+    virtual LInstruction* instr() V8_OVERRIDE { return instr_; }
    private:
     LNumberTagU* instr_;
   };
@@ -5033,12 +5037,14 @@ void LCodeGen::DoDeferredNumberTagI(LInstruction* instr,
 
 
 void LCodeGen::DoNumberTagD(LNumberTagD* instr) {
-  class DeferredNumberTagD: public LDeferredCode {
+  class DeferredNumberTagD V8_FINAL : public LDeferredCode {
    public:
     DeferredNumberTagD(LCodeGen* codegen, LNumberTagD* instr)
         : LDeferredCode(codegen), instr_(instr) { }
-    virtual void Generate() { codegen()->DoDeferredNumberTagD(instr_); }
-    virtual LInstruction* instr() { return instr_; }
+    virtual void Generate() V8_OVERRIDE {
+      codegen()->DoDeferredNumberTagD(instr_);
+    }
+    virtual LInstruction* instr() V8_OVERRIDE { return instr_; }
    private:
     LNumberTagD* instr_;
   };
@@ -5332,12 +5338,14 @@ void LCodeGen::DoDeferredTaggedToI(LTaggedToI* instr) {
 
 
 void LCodeGen::DoTaggedToI(LTaggedToI* instr) {
-  class DeferredTaggedToI: public LDeferredCode {
+  class DeferredTaggedToI V8_FINAL : public LDeferredCode {
    public:
     DeferredTaggedToI(LCodeGen* codegen, LTaggedToI* instr)
         : LDeferredCode(codegen), instr_(instr) { }
-    virtual void Generate() { codegen()->DoDeferredTaggedToI(instr_); }
-    virtual LInstruction* instr() { return instr_; }
+    virtual void Generate() V8_OVERRIDE {
+      codegen()->DoDeferredTaggedToI(instr_);
+    }
+    virtual LInstruction* instr() V8_OVERRIDE { return instr_; }
    private:
     LTaggedToI* instr_;
   };
@@ -5491,12 +5499,14 @@ void LCodeGen::DoDeferredTaggedToINoSSE2(LTaggedToINoSSE2* instr) {
 
 
 void LCodeGen::DoTaggedToINoSSE2(LTaggedToINoSSE2* instr) {
-  class DeferredTaggedToINoSSE2: public LDeferredCode {
+  class DeferredTaggedToINoSSE2 V8_FINAL : public LDeferredCode {
    public:
     DeferredTaggedToINoSSE2(LCodeGen* codegen, LTaggedToINoSSE2* instr)
         : LDeferredCode(codegen), instr_(instr) { }
-    virtual void Generate() { codegen()->DoDeferredTaggedToINoSSE2(instr_); }
-    virtual LInstruction* instr() { return instr_; }
+    virtual void Generate() V8_OVERRIDE {
+      codegen()->DoDeferredTaggedToINoSSE2(instr_);
+    }
+    virtual LInstruction* instr() V8_OVERRIDE { return instr_; }
    private:
     LTaggedToINoSSE2* instr_;
   };
@@ -5728,17 +5738,17 @@ void LCodeGen::DoDeferredInstanceMigration(LCheckMaps* instr, Register object) {
 
 
 void LCodeGen::DoCheckMaps(LCheckMaps* instr) {
-  class DeferredCheckMaps: public LDeferredCode {
+  class DeferredCheckMaps V8_FINAL : public LDeferredCode {
    public:
     DeferredCheckMaps(LCodeGen* codegen, LCheckMaps* instr, Register object)
         : LDeferredCode(codegen), instr_(instr), object_(object) {
       SetExit(check_maps());
     }
-    virtual void Generate() {
+    virtual void Generate() V8_OVERRIDE {
       codegen()->DoDeferredInstanceMigration(instr_, object_);
     }
     Label* check_maps() { return &check_maps_; }
-    virtual LInstruction* instr() { return instr_; }
+    virtual LInstruction* instr() V8_OVERRIDE { return instr_; }
    private:
     LCheckMaps* instr_;
     Label check_maps_;
@@ -5951,12 +5961,14 @@ void LCodeGen::DoClampTToUint8NoSSE2(LClampTToUint8NoSSE2* instr) {
 
 
 void LCodeGen::DoAllocate(LAllocate* instr) {
-  class DeferredAllocate: public LDeferredCode {
+  class DeferredAllocate V8_FINAL : public LDeferredCode {
    public:
     DeferredAllocate(LCodeGen* codegen, LAllocate* instr)
         : LDeferredCode(codegen), instr_(instr) { }
-    virtual void Generate() { codegen()->DoDeferredAllocate(instr_); }
-    virtual LInstruction* instr() { return instr_; }
+    virtual void Generate() V8_OVERRIDE {
+      codegen()->DoDeferredAllocate(instr_);
+    }
+    virtual LInstruction* instr() V8_OVERRIDE { return instr_; }
    private:
     LAllocate* instr_;
   };
@@ -6300,12 +6312,14 @@ void LCodeGen::DoDeferredStackCheck(LStackCheck* instr) {
 
 
 void LCodeGen::DoStackCheck(LStackCheck* instr) {
-  class DeferredStackCheck: public LDeferredCode {
+  class DeferredStackCheck V8_FINAL : public LDeferredCode {
    public:
     DeferredStackCheck(LCodeGen* codegen, LStackCheck* instr)
         : LDeferredCode(codegen), instr_(instr) { }
-    virtual void Generate() { codegen()->DoDeferredStackCheck(instr_); }
-    virtual LInstruction* instr() { return instr_; }
+    virtual void Generate() V8_OVERRIDE {
+      codegen()->DoDeferredStackCheck(instr_);
+    }
+    virtual LInstruction* instr() V8_OVERRIDE { return instr_; }
    private:
     LStackCheck* instr_;
   };
diff --git a/src/ia32/lithium-codegen-ia32.h b/src/ia32/lithium-codegen-ia32.h
index aa8f6c248a..e498f5363e 100644
--- a/src/ia32/lithium-codegen-ia32.h
+++ b/src/ia32/lithium-codegen-ia32.h
@@ -45,7 +45,7 @@ class LDeferredCode;
 class LGapNode;
 class SafepointGenerator;
 
-class LCodeGen BASE_EMBEDDED {
+class LCodeGen V8_FINAL BASE_EMBEDDED {
  public:
   LCodeGen(LChunk* chunk, MacroAssembler* assembler, CompilationInfo* info)
       : zone_(info->zone()),
@@ -452,7 +452,7 @@ class LCodeGen BASE_EMBEDDED {
 
   int old_position_;
 
-  class PushSafepointRegistersScope BASE_EMBEDDED {
+  class PushSafepointRegistersScope V8_FINAL  BASE_EMBEDDED {
    public:
     explicit PushSafepointRegistersScope(LCodeGen* codegen)
         : codegen_(codegen) {
@@ -479,7 +479,7 @@ class LCodeGen BASE_EMBEDDED {
 };
 
 
-class LDeferredCode: public ZoneObject {
+class LDeferredCode : public ZoneObject {
  public:
   explicit LDeferredCode(LCodeGen* codegen)
       : codegen_(codegen),
@@ -488,7 +488,7 @@ class LDeferredCode: public ZoneObject {
     codegen->AddDeferredCode(this);
   }
 
-  virtual ~LDeferredCode() { }
+  virtual ~LDeferredCode() {}
   virtual void Generate() = 0;
   virtual LInstruction* instr() = 0;
 
diff --git a/src/ia32/lithium-gap-resolver-ia32.h b/src/ia32/lithium-gap-resolver-ia32.h
index 3a58f585c3..4aff241f43 100644
--- a/src/ia32/lithium-gap-resolver-ia32.h
+++ b/src/ia32/lithium-gap-resolver-ia32.h
@@ -38,7 +38,7 @@ namespace internal {
 class LCodeGen;
 class LGapResolver;
 
-class LGapResolver BASE_EMBEDDED {
+class LGapResolver V8_FINAL BASE_EMBEDDED {
  public:
   explicit LGapResolver(LCodeGen* owner);
 
diff --git a/src/ia32/lithium-ia32.h b/src/ia32/lithium-ia32.h
index 7ae87a08c8..f35c7776b2 100644
--- a/src/ia32/lithium-ia32.h
+++ b/src/ia32/lithium-ia32.h
@@ -188,13 +188,17 @@ class LCodeGen;
   V(WrapReceiver)
 
 
-#define DECLARE_CONCRETE_INSTRUCTION(type, mnemonic)              \
-  virtual Opcode opcode() const { return LInstruction::k##type; } \
-  virtual void CompileToNative(LCodeGen* generator);              \
-  virtual const char* Mnemonic() const { return mnemonic; }       \
-  static L##type* cast(LInstruction* instr) {                     \
-    ASSERT(instr->Is##type());                                    \
-    return reinterpret_cast<L##type*>(instr);                     \
+#define DECLARE_CONCRETE_INSTRUCTION(type, mnemonic)                        \
+  virtual Opcode opcode() const V8_FINAL V8_OVERRIDE {                      \
+    return LInstruction::k##type;                                           \
+  }                                                                         \
+  virtual void CompileToNative(LCodeGen* generator) V8_FINAL V8_OVERRIDE;   \
+  virtual const char* Mnemonic() const V8_FINAL V8_OVERRIDE {               \
+    return mnemonic;                                                        \
+  }                                                                         \
+  static L##type* cast(LInstruction* instr) {                               \
+    ASSERT(instr->Is##type());                                              \
+    return reinterpret_cast<L##type*>(instr);                               \
   }
 
 
@@ -204,7 +208,7 @@ class LCodeGen;
   }
 
 
-class LInstruction: public ZoneObject {
+class LInstruction : public ZoneObject {
  public:
   LInstruction()
       : environment_(NULL),
@@ -213,7 +217,7 @@ class LInstruction: public ZoneObject {
     set_position(RelocInfo::kNoPosition);
   }
 
-  virtual ~LInstruction() { }
+  virtual ~LInstruction() {}
 
   virtual void CompileToNative(LCodeGen* generator) = 0;
   virtual const char* Mnemonic() const = 0;
@@ -319,11 +323,13 @@ class LInstruction: public ZoneObject {
 // I = number of input operands.
 // T = number of temporary operands.
 template<int R, int I, int T>
-class LTemplateInstruction: public LInstruction {
+class LTemplateInstruction : public LInstruction {
  public:
   // Allow 0 or 1 output operands.
   STATIC_ASSERT(R == 0 || R == 1);
-  virtual bool HasResult() const { return R != 0 && result() != NULL; }
+  virtual bool HasResult() const V8_FINAL V8_OVERRIDE {
+    return R != 0 && result() != NULL;
+  }
   void set_result(LOperand* operand) { results_[0] = operand; }
   LOperand* result() const { return results_[0]; }
 
@@ -334,15 +340,15 @@ class LTemplateInstruction: public LInstruction {
 
  private:
   // Iterator support.
-  virtual int InputCount() { return I; }
-  virtual LOperand* InputAt(int i) { return inputs_[i]; }
+  virtual int InputCount() V8_FINAL V8_OVERRIDE { return I; }
+  virtual LOperand* InputAt(int i) V8_FINAL V8_OVERRIDE { return inputs_[i]; }
 
-  virtual int TempCount() { return T; }
-  virtual LOperand* TempAt(int i) { return temps_[i]; }
+  virtual int TempCount() V8_FINAL V8_OVERRIDE { return T; }
+  virtual LOperand* TempAt(int i) V8_FINAL V8_OVERRIDE { return temps_[i]; }
 };
 
 
-class LGap: public LTemplateInstruction<0, 0, 0> {
+class LGap : public LTemplateInstruction<0, 0, 0> {
  public:
   explicit LGap(HBasicBlock* block) : block_(block) {
     parallel_moves_[BEFORE] = NULL;
@@ -352,8 +358,8 @@ class LGap: public LTemplateInstruction<0, 0, 0> {
   }
 
   // Can't use the DECLARE-macro here because of sub-classes.
-  virtual bool IsGap() const { return true; }
-  virtual void PrintDataTo(StringStream* stream);
+  virtual bool IsGap() const V8_FINAL V8_OVERRIDE { return true; }
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
   static LGap* cast(LInstruction* instr) {
     ASSERT(instr->IsGap());
     return reinterpret_cast<LGap*>(instr);
@@ -389,11 +395,11 @@ class LGap: public LTemplateInstruction<0, 0, 0> {
 };
 
 
-class LInstructionGap: public LGap {
+class LInstructionGap V8_FINAL : public LGap {
  public:
   explicit LInstructionGap(HBasicBlock* block) : LGap(block) { }
 
-  virtual bool HasInterestingComment(LCodeGen* gen) const {
+  virtual bool HasInterestingComment(LCodeGen* gen) const V8_OVERRIDE {
     return !IsRedundant();
   }
 
@@ -401,14 +407,14 @@ class LInstructionGap: public LGap {
 };
 
 
-class LGoto: public LTemplateInstruction<0, 0, 0> {
+class LGoto V8_FINAL : public LTemplateInstruction<0, 0, 0> {
  public:
   explicit LGoto(int block_id) : block_id_(block_id) { }
 
-  virtual bool HasInterestingComment(LCodeGen* gen) const;
+  virtual bool HasInterestingComment(LCodeGen* gen) const V8_OVERRIDE;
   DECLARE_CONCRETE_INSTRUCTION(Goto, "goto")
-  virtual void PrintDataTo(StringStream* stream);
-  virtual bool IsControl() const { return true; }
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
+  virtual bool IsControl() const V8_OVERRIDE { return true; }
 
   int block_id() const { return block_id_; }
 
@@ -417,13 +423,13 @@ class LGoto: public LTemplateInstruction<0, 0, 0> {
 };
 
 
-class LLazyBailout: public LTemplateInstruction<0, 0, 0> {
+class LLazyBailout V8_FINAL : public LTemplateInstruction<0, 0, 0> {
  public:
   DECLARE_CONCRETE_INSTRUCTION(LazyBailout, "lazy-bailout")
 };
 
 
-class LDummyUse: public LTemplateInstruction<1, 1, 0> {
+class LDummyUse V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LDummyUse(LOperand* value) {
     inputs_[0] = value;
@@ -432,22 +438,24 @@ class LDummyUse: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LDeoptimize: public LTemplateInstruction<0, 0, 0> {
+class LDeoptimize V8_FINAL : public LTemplateInstruction<0, 0, 0> {
  public:
   DECLARE_CONCRETE_INSTRUCTION(Deoptimize, "deoptimize")
   DECLARE_HYDROGEN_ACCESSOR(Deoptimize)
 };
 
 
-class LLabel: public LGap {
+class LLabel V8_FINAL : public LGap {
  public:
   explicit LLabel(HBasicBlock* block)
       : LGap(block), replacement_(NULL) { }
 
-  virtual bool HasInterestingComment(LCodeGen* gen) const { return false; }
+  virtual bool HasInterestingComment(LCodeGen* gen) const V8_OVERRIDE {
+    return false;
+  }
   DECLARE_CONCRETE_INSTRUCTION(Label, "label")
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
   int block_id() const { return block()->block_id(); }
   bool is_loop_header() const { return block()->IsLoopHeader(); }
@@ -463,14 +471,16 @@ class LLabel: public LGap {
 };
 
 
-class LParameter: public LTemplateInstruction<1, 0, 0> {
+class LParameter V8_FINAL : public LTemplateInstruction<1, 0, 0> {
  public:
-  virtual bool HasInterestingComment(LCodeGen* gen) const { return false; }
+  virtual bool HasInterestingComment(LCodeGen* gen) const V8_OVERRIDE {
+    return false;
+  }
   DECLARE_CONCRETE_INSTRUCTION(Parameter, "parameter")
 };
 
 
-class LCallStub: public LTemplateInstruction<1, 1, 0> {
+class LCallStub V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LCallStub(LOperand* context) {
     inputs_[0] = context;
@@ -487,9 +497,11 @@ class LCallStub: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LUnknownOSRValue: public LTemplateInstruction<1, 0, 0> {
+class LUnknownOSRValue V8_FINAL : public LTemplateInstruction<1, 0, 0> {
  public:
-  virtual bool HasInterestingComment(LCodeGen* gen) const { return false; }
+  virtual bool HasInterestingComment(LCodeGen* gen) const V8_OVERRIDE {
+    return false;
+  }
   DECLARE_CONCRETE_INSTRUCTION(UnknownOSRValue, "unknown-osr-value")
 };
 
@@ -499,7 +511,7 @@ class LControlInstruction: public LTemplateInstruction<0, I, T> {
  public:
   LControlInstruction() : false_label_(NULL), true_label_(NULL) { }
 
-  virtual bool IsControl() const { return true; }
+  virtual bool IsControl() const V8_FINAL V8_OVERRIDE { return true; }
 
   int SuccessorCount() { return hydrogen()->SuccessorCount(); }
   HBasicBlock* SuccessorAt(int i) { return hydrogen()->SuccessorAt(i); }
@@ -538,7 +550,7 @@ class LControlInstruction: public LTemplateInstruction<0, I, T> {
 };
 
 
-class LWrapReceiver: public LTemplateInstruction<1, 2, 1> {
+class LWrapReceiver V8_FINAL : public LTemplateInstruction<1, 2, 1> {
  public:
   LWrapReceiver(LOperand* receiver,
                 LOperand* function,
@@ -556,7 +568,7 @@ class LWrapReceiver: public LTemplateInstruction<1, 2, 1> {
 };
 
 
-class LApplyArguments: public LTemplateInstruction<1, 4, 0> {
+class LApplyArguments V8_FINAL : public LTemplateInstruction<1, 4, 0> {
  public:
   LApplyArguments(LOperand* function,
                   LOperand* receiver,
@@ -577,7 +589,7 @@ class LApplyArguments: public LTemplateInstruction<1, 4, 0> {
 };
 
 
-class LAccessArgumentsAt: public LTemplateInstruction<1, 3, 0> {
+class LAccessArgumentsAt V8_FINAL : public LTemplateInstruction<1, 3, 0> {
  public:
   LAccessArgumentsAt(LOperand* arguments, LOperand* length, LOperand* index) {
     inputs_[0] = arguments;
@@ -591,11 +603,11 @@ class LAccessArgumentsAt: public LTemplateInstruction<1, 3, 0> {
 
   DECLARE_CONCRETE_INSTRUCTION(AccessArgumentsAt, "access-arguments-at")
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 };
 
 
-class LArgumentsLength: public LTemplateInstruction<1, 1, 0> {
+class LArgumentsLength V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LArgumentsLength(LOperand* elements) {
     inputs_[0] = elements;
@@ -607,20 +619,20 @@ class LArgumentsLength: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LArgumentsElements: public LTemplateInstruction<1, 0, 0> {
+class LArgumentsElements V8_FINAL : public LTemplateInstruction<1, 0, 0> {
  public:
   DECLARE_CONCRETE_INSTRUCTION(ArgumentsElements, "arguments-elements")
   DECLARE_HYDROGEN_ACCESSOR(ArgumentsElements)
 };
 
 
-class LDebugBreak: public LTemplateInstruction<0, 0, 0> {
+class LDebugBreak V8_FINAL : public LTemplateInstruction<0, 0, 0> {
  public:
   DECLARE_CONCRETE_INSTRUCTION(DebugBreak, "break")
 };
 
 
-class LModI: public LTemplateInstruction<1, 2, 1> {
+class LModI V8_FINAL : public LTemplateInstruction<1, 2, 1> {
  public:
   LModI(LOperand* left, LOperand* right, LOperand* temp) {
     inputs_[0] = left;
@@ -637,7 +649,7 @@ class LModI: public LTemplateInstruction<1, 2, 1> {
 };
 
 
-class LDivI: public LTemplateInstruction<1, 2, 1> {
+class LDivI V8_FINAL : public LTemplateInstruction<1, 2, 1> {
  public:
   LDivI(LOperand* left, LOperand* right, LOperand* temp) {
     inputs_[0] = left;
@@ -655,7 +667,7 @@ class LDivI: public LTemplateInstruction<1, 2, 1> {
 };
 
 
-class LMathFloorOfDiv: public LTemplateInstruction<1, 2, 1> {
+class LMathFloorOfDiv V8_FINAL : public LTemplateInstruction<1, 2, 1> {
  public:
   LMathFloorOfDiv(LOperand* left,
                   LOperand* right,
@@ -674,7 +686,7 @@ class LMathFloorOfDiv: public LTemplateInstruction<1, 2, 1> {
 };
 
 
-class LMulI: public LTemplateInstruction<1, 2, 1> {
+class LMulI V8_FINAL : public LTemplateInstruction<1, 2, 1> {
  public:
   LMulI(LOperand* left, LOperand* right, LOperand* temp) {
     inputs_[0] = left;
@@ -691,7 +703,7 @@ class LMulI: public LTemplateInstruction<1, 2, 1> {
 };
 
 
-class LCompareNumericAndBranch: public LControlInstruction<2, 0> {
+class LCompareNumericAndBranch V8_FINAL : public LControlInstruction<2, 0> {
  public:
   LCompareNumericAndBranch(LOperand* left, LOperand* right) {
     inputs_[0] = left;
@@ -714,7 +726,7 @@ class LCompareNumericAndBranch: public LControlInstruction<2, 0> {
 };
 
 
-class LMathFloor: public LTemplateInstruction<1, 1, 0> {
+class LMathFloor V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LMathFloor(LOperand* value) {
     inputs_[0] = value;
@@ -727,7 +739,7 @@ class LMathFloor: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LMathRound: public LTemplateInstruction<1, 2, 1> {
+class LMathRound V8_FINAL : public LTemplateInstruction<1, 2, 1> {
  public:
   LMathRound(LOperand* context, LOperand* value, LOperand* temp) {
     inputs_[1] = context;
@@ -744,7 +756,7 @@ class LMathRound: public LTemplateInstruction<1, 2, 1> {
 };
 
 
-class LMathAbs: public LTemplateInstruction<1, 2, 0> {
+class LMathAbs V8_FINAL : public LTemplateInstruction<1, 2, 0> {
  public:
   LMathAbs(LOperand* context, LOperand* value) {
     inputs_[1] = context;
@@ -759,7 +771,7 @@ class LMathAbs: public LTemplateInstruction<1, 2, 0> {
 };
 
 
-class LMathLog: public LTemplateInstruction<1, 1, 0> {
+class LMathLog V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LMathLog(LOperand* value) {
     inputs_[0] = value;
@@ -771,7 +783,7 @@ class LMathLog: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LMathSin: public LTemplateInstruction<1, 1, 0> {
+class LMathSin V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LMathSin(LOperand* value) {
     inputs_[0] = value;
@@ -783,7 +795,7 @@ class LMathSin: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LMathCos: public LTemplateInstruction<1, 1, 0> {
+class LMathCos V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LMathCos(LOperand* value) {
     inputs_[0] = value;
@@ -795,7 +807,7 @@ class LMathCos: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LMathTan: public LTemplateInstruction<1, 1, 0> {
+class LMathTan V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LMathTan(LOperand* value) {
     inputs_[0] = value;
@@ -807,7 +819,7 @@ class LMathTan: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LMathExp: public LTemplateInstruction<1, 1, 2> {
+class LMathExp V8_FINAL : public LTemplateInstruction<1, 1, 2> {
  public:
   LMathExp(LOperand* value,
            LOperand* temp1,
@@ -826,7 +838,7 @@ class LMathExp: public LTemplateInstruction<1, 1, 2> {
 };
 
 
-class LMathSqrt: public LTemplateInstruction<1, 1, 0> {
+class LMathSqrt V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LMathSqrt(LOperand* value) {
     inputs_[0] = value;
@@ -838,7 +850,7 @@ class LMathSqrt: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LMathPowHalf: public LTemplateInstruction<1, 2, 1> {
+class LMathPowHalf V8_FINAL : public LTemplateInstruction<1, 2, 1> {
  public:
   LMathPowHalf(LOperand* context, LOperand* value, LOperand* temp) {
     inputs_[1] = context;
@@ -854,7 +866,7 @@ class LMathPowHalf: public LTemplateInstruction<1, 2, 1> {
 };
 
 
-class LCmpObjectEqAndBranch: public LControlInstruction<2, 0> {
+class LCmpObjectEqAndBranch V8_FINAL : public LControlInstruction<2, 0> {
  public:
   LCmpObjectEqAndBranch(LOperand* left, LOperand* right) {
     inputs_[0] = left;
@@ -868,7 +880,7 @@ class LCmpObjectEqAndBranch: public LControlInstruction<2, 0> {
 };
 
 
-class LCmpHoleAndBranch: public LControlInstruction<1, 0> {
+class LCmpHoleAndBranch V8_FINAL : public LControlInstruction<1, 0> {
  public:
   explicit LCmpHoleAndBranch(LOperand* object) {
     inputs_[0] = object;
@@ -881,7 +893,7 @@ class LCmpHoleAndBranch: public LControlInstruction<1, 0> {
 };
 
 
-class LIsObjectAndBranch: public LControlInstruction<1, 1> {
+class LIsObjectAndBranch V8_FINAL : public LControlInstruction<1, 1> {
  public:
   LIsObjectAndBranch(LOperand* value, LOperand* temp) {
     inputs_[0] = value;
@@ -893,11 +905,11 @@ class LIsObjectAndBranch: public LControlInstruction<1, 1> {
 
   DECLARE_CONCRETE_INSTRUCTION(IsObjectAndBranch, "is-object-and-branch")
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 };
 
 
-class LIsNumberAndBranch: public LControlInstruction<1, 0> {
+class LIsNumberAndBranch V8_FINAL : public LControlInstruction<1, 0> {
  public:
   explicit LIsNumberAndBranch(LOperand* value) {
     inputs_[0] = value;
@@ -910,7 +922,7 @@ class LIsNumberAndBranch: public LControlInstruction<1, 0> {
 };
 
 
-class LIsStringAndBranch: public LControlInstruction<1, 1> {
+class LIsStringAndBranch V8_FINAL : public LControlInstruction<1, 1> {
  public:
   LIsStringAndBranch(LOperand* value, LOperand* temp) {
     inputs_[0] = value;
@@ -923,11 +935,11 @@ class LIsStringAndBranch: public LControlInstruction<1, 1> {
   DECLARE_CONCRETE_INSTRUCTION(IsStringAndBranch, "is-string-and-branch")
   DECLARE_HYDROGEN_ACCESSOR(IsStringAndBranch)
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 };
 
 
-class LIsSmiAndBranch: public LControlInstruction<1, 0> {
+class LIsSmiAndBranch V8_FINAL : public LControlInstruction<1, 0> {
  public:
   explicit LIsSmiAndBranch(LOperand* value) {
     inputs_[0] = value;
@@ -938,11 +950,11 @@ class LIsSmiAndBranch: public LControlInstruction<1, 0> {
   DECLARE_CONCRETE_INSTRUCTION(IsSmiAndBranch, "is-smi-and-branch")
   DECLARE_HYDROGEN_ACCESSOR(IsSmiAndBranch)
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 };
 
 
-class LIsUndetectableAndBranch: public LControlInstruction<1, 1> {
+class LIsUndetectableAndBranch V8_FINAL : public LControlInstruction<1, 1> {
  public:
   LIsUndetectableAndBranch(LOperand* value, LOperand* temp) {
     inputs_[0] = value;
@@ -956,11 +968,11 @@ class LIsUndetectableAndBranch: public LControlInstruction<1, 1> {
                                "is-undetectable-and-branch")
   DECLARE_HYDROGEN_ACCESSOR(IsUndetectableAndBranch)
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 };
 
 
-class LStringCompareAndBranch: public LControlInstruction<3, 0> {
+class LStringCompareAndBranch V8_FINAL : public LControlInstruction<3, 0> {
  public:
   LStringCompareAndBranch(LOperand* context, LOperand* left, LOperand* right) {
     inputs_[0] = context;
@@ -975,13 +987,13 @@ class LStringCompareAndBranch: public LControlInstruction<3, 0> {
                                "string-compare-and-branch")
   DECLARE_HYDROGEN_ACCESSOR(StringCompareAndBranch)
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
   Token::Value op() const { return hydrogen()->token(); }
 };
 
 
-class LHasInstanceTypeAndBranch: public LControlInstruction<1, 1> {
+class LHasInstanceTypeAndBranch V8_FINAL : public LControlInstruction<1, 1> {
  public:
   LHasInstanceTypeAndBranch(LOperand* value, LOperand* temp) {
     inputs_[0] = value;
@@ -995,11 +1007,11 @@ class LHasInstanceTypeAndBranch: public LControlInstruction<1, 1> {
                                "has-instance-type-and-branch")
   DECLARE_HYDROGEN_ACCESSOR(HasInstanceTypeAndBranch)
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 };
 
 
-class LGetCachedArrayIndex: public LTemplateInstruction<1, 1, 0> {
+class LGetCachedArrayIndex V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LGetCachedArrayIndex(LOperand* value) {
     inputs_[0] = value;
@@ -1012,7 +1024,8 @@ class LGetCachedArrayIndex: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LHasCachedArrayIndexAndBranch: public LControlInstruction<1, 0> {
+class LHasCachedArrayIndexAndBranch V8_FINAL
+    : public LControlInstruction<1, 0> {
  public:
   explicit LHasCachedArrayIndexAndBranch(LOperand* value) {
     inputs_[0] = value;
@@ -1023,11 +1036,11 @@ class LHasCachedArrayIndexAndBranch: public LControlInstruction<1, 0> {
   DECLARE_CONCRETE_INSTRUCTION(HasCachedArrayIndexAndBranch,
                                "has-cached-array-index-and-branch")
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 };
 
 
-class LIsConstructCallAndBranch: public LControlInstruction<0, 1> {
+class LIsConstructCallAndBranch V8_FINAL : public LControlInstruction<0, 1> {
  public:
   explicit LIsConstructCallAndBranch(LOperand* temp) {
     temps_[0] = temp;
@@ -1040,7 +1053,7 @@ class LIsConstructCallAndBranch: public LControlInstruction<0, 1> {
 };
 
 
-class LClassOfTestAndBranch: public LControlInstruction<1, 2> {
+class LClassOfTestAndBranch V8_FINAL : public LControlInstruction<1, 2> {
  public:
   LClassOfTestAndBranch(LOperand* value, LOperand* temp, LOperand* temp2) {
     inputs_[0] = value;
@@ -1056,11 +1069,11 @@ class LClassOfTestAndBranch: public LControlInstruction<1, 2> {
                                "class-of-test-and-branch")
   DECLARE_HYDROGEN_ACCESSOR(ClassOfTestAndBranch)
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 };
 
 
-class LCmpT: public LTemplateInstruction<1, 3, 0> {
+class LCmpT V8_FINAL : public LTemplateInstruction<1, 3, 0> {
  public:
   LCmpT(LOperand* context, LOperand* left, LOperand* right) {
     inputs_[0] = context;
@@ -1075,7 +1088,7 @@ class LCmpT: public LTemplateInstruction<1, 3, 0> {
 };
 
 
-class LInstanceOf: public LTemplateInstruction<1, 3, 0> {
+class LInstanceOf V8_FINAL : public LTemplateInstruction<1, 3, 0> {
  public:
   LInstanceOf(LOperand* context, LOperand* left, LOperand* right) {
     inputs_[0] = context;
@@ -1089,7 +1102,7 @@ class LInstanceOf: public LTemplateInstruction<1, 3, 0> {
 };
 
 
-class LInstanceOfKnownGlobal: public LTemplateInstruction<1, 2, 1> {
+class LInstanceOfKnownGlobal V8_FINAL : public LTemplateInstruction<1, 2, 1> {
  public:
   LInstanceOfKnownGlobal(LOperand* context, LOperand* value, LOperand* temp) {
     inputs_[0] = context;
@@ -1108,7 +1121,8 @@ class LInstanceOfKnownGlobal: public LTemplateInstruction<1, 2, 1> {
   LEnvironment* GetDeferredLazyDeoptimizationEnvironment() {
     return lazy_deopt_env_;
   }
-  virtual void SetDeferredLazyDeoptimizationEnvironment(LEnvironment* env) {
+  virtual void SetDeferredLazyDeoptimizationEnvironment(
+      LEnvironment* env) V8_OVERRIDE {
     lazy_deopt_env_ = env;
   }
 
@@ -1117,7 +1131,7 @@ class LInstanceOfKnownGlobal: public LTemplateInstruction<1, 2, 1> {
 };
 
 
-class LInstanceSize: public LTemplateInstruction<1, 1, 0> {
+class LInstanceSize V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LInstanceSize(LOperand* object) {
     inputs_[0] = object;
@@ -1130,7 +1144,7 @@ class LInstanceSize: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LBoundsCheck: public LTemplateInstruction<0, 2, 0> {
+class LBoundsCheck V8_FINAL : public LTemplateInstruction<0, 2, 0> {
  public:
   LBoundsCheck(LOperand* index, LOperand* length) {
     inputs_[0] = index;
@@ -1145,7 +1159,7 @@ class LBoundsCheck: public LTemplateInstruction<0, 2, 0> {
 };
 
 
-class LBitI: public LTemplateInstruction<1, 2, 0> {
+class LBitI V8_FINAL : public LTemplateInstruction<1, 2, 0> {
  public:
   LBitI(LOperand* left, LOperand* right) {
     inputs_[0] = left;
@@ -1162,7 +1176,7 @@ class LBitI: public LTemplateInstruction<1, 2, 0> {
 };
 
 
-class LShiftI: public LTemplateInstruction<1, 2, 0> {
+class LShiftI V8_FINAL : public LTemplateInstruction<1, 2, 0> {
  public:
   LShiftI(Token::Value op, LOperand* left, LOperand* right, bool can_deopt)
       : op_(op), can_deopt_(can_deopt) {
@@ -1184,7 +1198,7 @@ class LShiftI: public LTemplateInstruction<1, 2, 0> {
 };
 
 
-class LSubI: public LTemplateInstruction<1, 2, 0> {
+class LSubI V8_FINAL : public LTemplateInstruction<1, 2, 0> {
  public:
   LSubI(LOperand* left, LOperand* right) {
     inputs_[0] = left;
@@ -1199,7 +1213,7 @@ class LSubI: public LTemplateInstruction<1, 2, 0> {
 };
 
 
-class LConstantI: public LTemplateInstruction<1, 0, 0> {
+class LConstantI V8_FINAL : public LTemplateInstruction<1, 0, 0> {
  public:
   DECLARE_CONCRETE_INSTRUCTION(ConstantI, "constant-i")
   DECLARE_HYDROGEN_ACCESSOR(Constant)
@@ -1208,7 +1222,7 @@ class LConstantI: public LTemplateInstruction<1, 0, 0> {
 };
 
 
-class LConstantS: public LTemplateInstruction<1, 0, 0> {
+class LConstantS V8_FINAL : public LTemplateInstruction<1, 0, 0> {
  public:
   DECLARE_CONCRETE_INSTRUCTION(ConstantS, "constant-s")
   DECLARE_HYDROGEN_ACCESSOR(Constant)
@@ -1217,7 +1231,7 @@ class LConstantS: public LTemplateInstruction<1, 0, 0> {
 };
 
 
-class LConstantD: public LTemplateInstruction<1, 0, 1> {
+class LConstantD V8_FINAL : public LTemplateInstruction<1, 0, 1> {
  public:
   explicit LConstantD(LOperand* temp) {
     temps_[0] = temp;
@@ -1232,7 +1246,7 @@ class LConstantD: public LTemplateInstruction<1, 0, 1> {
 };
 
 
-class LConstantE: public LTemplateInstruction<1, 0, 0> {
+class LConstantE V8_FINAL : public LTemplateInstruction<1, 0, 0> {
  public:
   DECLARE_CONCRETE_INSTRUCTION(ConstantE, "constant-e")
   DECLARE_HYDROGEN_ACCESSOR(Constant)
@@ -1243,7 +1257,7 @@ class LConstantE: public LTemplateInstruction<1, 0, 0> {
 };
 
 
-class LConstantT: public LTemplateInstruction<1, 0, 0> {
+class LConstantT V8_FINAL : public LTemplateInstruction<1, 0, 0> {
  public:
   DECLARE_CONCRETE_INSTRUCTION(ConstantT, "constant-t")
   DECLARE_HYDROGEN_ACCESSOR(Constant)
@@ -1252,7 +1266,7 @@ class LConstantT: public LTemplateInstruction<1, 0, 0> {
 };
 
 
-class LBranch: public LControlInstruction<1, 1> {
+class LBranch V8_FINAL : public LControlInstruction<1, 1> {
  public:
   LBranch(LOperand* value, LOperand* temp) {
     inputs_[0] = value;
@@ -1265,11 +1279,11 @@ class LBranch: public LControlInstruction<1, 1> {
   DECLARE_CONCRETE_INSTRUCTION(Branch, "branch")
   DECLARE_HYDROGEN_ACCESSOR(Branch)
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 };
 
 
-class LCmpMapAndBranch: public LControlInstruction<1, 0> {
+class LCmpMapAndBranch V8_FINAL : public LControlInstruction<1, 0> {
  public:
   explicit LCmpMapAndBranch(LOperand* value) {
     inputs_[0] = value;
@@ -1284,7 +1298,7 @@ class LCmpMapAndBranch: public LControlInstruction<1, 0> {
 };
 
 
-class LMapEnumLength: public LTemplateInstruction<1, 1, 0> {
+class LMapEnumLength V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LMapEnumLength(LOperand* value) {
     inputs_[0] = value;
@@ -1296,7 +1310,7 @@ class LMapEnumLength: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LElementsKind: public LTemplateInstruction<1, 1, 0> {
+class LElementsKind V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LElementsKind(LOperand* value) {
     inputs_[0] = value;
@@ -1309,7 +1323,7 @@ class LElementsKind: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LValueOf: public LTemplateInstruction<1, 1, 1> {
+class LValueOf V8_FINAL : public LTemplateInstruction<1, 1, 1> {
  public:
   LValueOf(LOperand* value, LOperand* temp) {
     inputs_[0] = value;
@@ -1324,7 +1338,7 @@ class LValueOf: public LTemplateInstruction<1, 1, 1> {
 };
 
 
-class LDateField: public LTemplateInstruction<1, 1, 1> {
+class LDateField V8_FINAL : public LTemplateInstruction<1, 1, 1> {
  public:
   LDateField(LOperand* date, LOperand* temp, Smi* index)
       : index_(index) {
@@ -1345,7 +1359,7 @@ class LDateField: public LTemplateInstruction<1, 1, 1> {
 };
 
 
-class LSeqStringSetChar: public LTemplateInstruction<1, 3, 0> {
+class LSeqStringSetChar V8_FINAL : public LTemplateInstruction<1, 3, 0> {
  public:
   LSeqStringSetChar(String::Encoding encoding,
                     LOperand* string,
@@ -1369,7 +1383,7 @@ class LSeqStringSetChar: public LTemplateInstruction<1, 3, 0> {
 };
 
 
-class LThrow: public LTemplateInstruction<0, 2, 0> {
+class LThrow V8_FINAL : public LTemplateInstruction<0, 2, 0> {
  public:
   LThrow(LOperand* context, LOperand* value) {
     inputs_[0] = context;
@@ -1383,7 +1397,7 @@ class LThrow: public LTemplateInstruction<0, 2, 0> {
 };
 
 
-class LAddI: public LTemplateInstruction<1, 2, 0> {
+class LAddI V8_FINAL : public LTemplateInstruction<1, 2, 0> {
  public:
   LAddI(LOperand* left, LOperand* right) {
     inputs_[0] = left;
@@ -1403,7 +1417,7 @@ class LAddI: public LTemplateInstruction<1, 2, 0> {
 };
 
 
-class LMathMinMax: public LTemplateInstruction<1, 2, 0> {
+class LMathMinMax V8_FINAL : public LTemplateInstruction<1, 2, 0> {
  public:
   LMathMinMax(LOperand* left, LOperand* right) {
     inputs_[0] = left;
@@ -1418,7 +1432,7 @@ class LMathMinMax: public LTemplateInstruction<1, 2, 0> {
 };
 
 
-class LPower: public LTemplateInstruction<1, 2, 0> {
+class LPower V8_FINAL : public LTemplateInstruction<1, 2, 0> {
  public:
   LPower(LOperand* left, LOperand* right) {
     inputs_[0] = left;
@@ -1433,7 +1447,7 @@ class LPower: public LTemplateInstruction<1, 2, 0> {
 };
 
 
-class LRandom: public LTemplateInstruction<1, 1, 0> {
+class LRandom V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LRandom(LOperand* global_object) {
     inputs_[0] = global_object;
@@ -1446,7 +1460,7 @@ class LRandom: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LArithmeticD: public LTemplateInstruction<1, 2, 0> {
+class LArithmeticD V8_FINAL : public LTemplateInstruction<1, 2, 0> {
  public:
   LArithmeticD(Token::Value op, LOperand* left, LOperand* right)
       : op_(op) {
@@ -1459,16 +1473,18 @@ class LArithmeticD: public LTemplateInstruction<1, 2, 0> {
 
   Token::Value op() const { return op_; }
 
-  virtual Opcode opcode() const { return LInstruction::kArithmeticD; }
-  virtual void CompileToNative(LCodeGen* generator);
-  virtual const char* Mnemonic() const;
+  virtual Opcode opcode() const V8_OVERRIDE {
+    return LInstruction::kArithmeticD;
+  }
+  virtual void CompileToNative(LCodeGen* generator) V8_OVERRIDE;
+  virtual const char* Mnemonic() const V8_OVERRIDE;
 
  private:
   Token::Value op_;
 };
 
 
-class LArithmeticT: public LTemplateInstruction<1, 3, 0> {
+class LArithmeticT V8_FINAL : public LTemplateInstruction<1, 3, 0> {
  public:
   LArithmeticT(Token::Value op,
                LOperand* context,
@@ -1484,9 +1500,11 @@ class LArithmeticT: public LTemplateInstruction<1, 3, 0> {
   LOperand* left() { return inputs_[1]; }
   LOperand* right() { return inputs_[2]; }
 
-  virtual Opcode opcode() const { return LInstruction::kArithmeticT; }
-  virtual void CompileToNative(LCodeGen* generator);
-  virtual const char* Mnemonic() const;
+  virtual Opcode opcode() const V8_OVERRIDE {
+    return LInstruction::kArithmeticT;
+  }
+  virtual void CompileToNative(LCodeGen* generator) V8_OVERRIDE;
+  virtual const char* Mnemonic() const V8_OVERRIDE;
 
   Token::Value op() const { return op_; }
 
@@ -1495,7 +1513,7 @@ class LArithmeticT: public LTemplateInstruction<1, 3, 0> {
 };
 
 
-class LReturn: public LTemplateInstruction<0, 3, 0> {
+class LReturn V8_FINAL : public LTemplateInstruction<0, 3, 0> {
  public:
   explicit LReturn(LOperand* value, LOperand* context,
                    LOperand* parameter_count) {
@@ -1518,7 +1536,7 @@ class LReturn: public LTemplateInstruction<0, 3, 0> {
 };
 
 
-class LLoadNamedField: public LTemplateInstruction<1, 1, 0> {
+class LLoadNamedField V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LLoadNamedField(LOperand* object) {
     inputs_[0] = object;
@@ -1536,7 +1554,7 @@ class LLoadNamedField: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LLoadNamedGeneric: public LTemplateInstruction<1, 2, 0> {
+class LLoadNamedGeneric V8_FINAL : public LTemplateInstruction<1, 2, 0> {
  public:
   LLoadNamedGeneric(LOperand* context, LOperand* object) {
     inputs_[0] = context;
@@ -1553,7 +1571,7 @@ class LLoadNamedGeneric: public LTemplateInstruction<1, 2, 0> {
 };
 
 
-class LLoadFunctionPrototype: public LTemplateInstruction<1, 1, 1> {
+class LLoadFunctionPrototype V8_FINAL : public LTemplateInstruction<1, 1, 1> {
  public:
   LLoadFunctionPrototype(LOperand* function, LOperand* temp) {
     inputs_[0] = function;
@@ -1568,7 +1586,8 @@ class LLoadFunctionPrototype: public LTemplateInstruction<1, 1, 1> {
 };
 
 
-class LLoadExternalArrayPointer: public LTemplateInstruction<1, 1, 0> {
+class LLoadExternalArrayPointer V8_FINAL
+    : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LLoadExternalArrayPointer(LOperand* object) {
     inputs_[0] = object;
@@ -1581,7 +1600,7 @@ class LLoadExternalArrayPointer: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LLoadKeyed: public LTemplateInstruction<1, 2, 0> {
+class LLoadKeyed V8_FINAL : public LTemplateInstruction<1, 2, 0> {
  public:
   LLoadKeyed(LOperand* elements, LOperand* key) {
     inputs_[0] = elements;
@@ -1596,7 +1615,7 @@ class LLoadKeyed: public LTemplateInstruction<1, 2, 0> {
     return hydrogen()->is_external();
   }
 
-  virtual bool ClobbersDoubleRegisters() const {
+  virtual bool ClobbersDoubleRegisters() const V8_OVERRIDE {
     return !CpuFeatures::IsSupported(SSE2) &&
         !IsDoubleOrFloatElementsKind(hydrogen()->elements_kind());
   }
@@ -1604,7 +1623,7 @@ class LLoadKeyed: public LTemplateInstruction<1, 2, 0> {
   DECLARE_CONCRETE_INSTRUCTION(LoadKeyed, "load-keyed")
   DECLARE_HYDROGEN_ACCESSOR(LoadKeyed)
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
   uint32_t additional_index() const { return hydrogen()->index_offset(); }
   bool key_is_smi() {
     return hydrogen()->key()->representation().IsTagged();
@@ -1625,7 +1644,7 @@ inline static bool ExternalArrayOpRequiresTemp(
 }
 
 
-class LLoadKeyedGeneric: public LTemplateInstruction<1, 3, 0> {
+class LLoadKeyedGeneric V8_FINAL : public LTemplateInstruction<1, 3, 0> {
  public:
   LLoadKeyedGeneric(LOperand* context, LOperand* obj, LOperand* key) {
     inputs_[0] = context;
@@ -1641,14 +1660,14 @@ class LLoadKeyedGeneric: public LTemplateInstruction<1, 3, 0> {
 };
 
 
-class LLoadGlobalCell: public LTemplateInstruction<1, 0, 0> {
+class LLoadGlobalCell V8_FINAL : public LTemplateInstruction<1, 0, 0> {
  public:
   DECLARE_CONCRETE_INSTRUCTION(LoadGlobalCell, "load-global-cell")
   DECLARE_HYDROGEN_ACCESSOR(LoadGlobalCell)
 };
 
 
-class LLoadGlobalGeneric: public LTemplateInstruction<1, 2, 0> {
+class LLoadGlobalGeneric V8_FINAL : public LTemplateInstruction<1, 2, 0> {
  public:
   LLoadGlobalGeneric(LOperand* context, LOperand* global_object) {
     inputs_[0] = context;
@@ -1666,7 +1685,7 @@ class LLoadGlobalGeneric: public LTemplateInstruction<1, 2, 0> {
 };
 
 
-class LStoreGlobalCell: public LTemplateInstruction<0, 1, 0> {
+class LStoreGlobalCell V8_FINAL : public LTemplateInstruction<0, 1, 0> {
  public:
   explicit LStoreGlobalCell(LOperand* value) {
     inputs_[0] = value;
@@ -1679,7 +1698,7 @@ class LStoreGlobalCell: public LTemplateInstruction<0, 1, 0> {
 };
 
 
-class LStoreGlobalGeneric: public LTemplateInstruction<0, 3, 0> {
+class LStoreGlobalGeneric V8_FINAL : public LTemplateInstruction<0, 3, 0> {
  public:
   LStoreGlobalGeneric(LOperand* context,
                       LOperand* global_object,
@@ -1701,7 +1720,7 @@ class LStoreGlobalGeneric: public LTemplateInstruction<0, 3, 0> {
 };
 
 
-class LLoadContextSlot: public LTemplateInstruction<1, 1, 0> {
+class LLoadContextSlot V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LLoadContextSlot(LOperand* context) {
     inputs_[0] = context;
@@ -1714,11 +1733,11 @@ class LLoadContextSlot: public LTemplateInstruction<1, 1, 0> {
 
   int slot_index() { return hydrogen()->slot_index(); }
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 };
 
 
-class LStoreContextSlot: public LTemplateInstruction<0, 2, 1> {
+class LStoreContextSlot V8_FINAL : public LTemplateInstruction<0, 2, 1> {
  public:
   LStoreContextSlot(LOperand* context, LOperand* value, LOperand* temp) {
     inputs_[0] = context;
@@ -1735,11 +1754,11 @@ class LStoreContextSlot: public LTemplateInstruction<0, 2, 1> {
 
   int slot_index() { return hydrogen()->slot_index(); }
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 };
 
 
-class LPushArgument: public LTemplateInstruction<0, 1, 0> {
+class LPushArgument V8_FINAL : public LTemplateInstruction<0, 1, 0> {
  public:
   explicit LPushArgument(LOperand* value) {
     inputs_[0] = value;
@@ -1751,7 +1770,7 @@ class LPushArgument: public LTemplateInstruction<0, 1, 0> {
 };
 
 
-class LDrop: public LTemplateInstruction<0, 0, 0> {
+class LDrop V8_FINAL : public LTemplateInstruction<0, 0, 0> {
  public:
   explicit LDrop(int count) : count_(count) { }
 
@@ -1764,7 +1783,7 @@ class LDrop: public LTemplateInstruction<0, 0, 0> {
 };
 
 
-class LInnerAllocatedObject: public LTemplateInstruction<1, 1, 0> {
+class LInnerAllocatedObject V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LInnerAllocatedObject(LOperand* base_object) {
     inputs_[0] = base_object;
@@ -1780,21 +1799,21 @@ class LInnerAllocatedObject: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LThisFunction: public LTemplateInstruction<1, 0, 0> {
+class LThisFunction V8_FINAL : public LTemplateInstruction<1, 0, 0> {
  public:
   DECLARE_CONCRETE_INSTRUCTION(ThisFunction, "this-function")
   DECLARE_HYDROGEN_ACCESSOR(ThisFunction)
 };
 
 
-class LContext: public LTemplateInstruction<1, 0, 0> {
+class LContext V8_FINAL : public LTemplateInstruction<1, 0, 0> {
  public:
   DECLARE_CONCRETE_INSTRUCTION(Context, "context")
   DECLARE_HYDROGEN_ACCESSOR(Context)
 };
 
 
-class LOuterContext: public LTemplateInstruction<1, 1, 0> {
+class LOuterContext V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LOuterContext(LOperand* context) {
     inputs_[0] = context;
@@ -1806,7 +1825,7 @@ class LOuterContext: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LDeclareGlobals: public LTemplateInstruction<0, 1, 0> {
+class LDeclareGlobals V8_FINAL : public LTemplateInstruction<0, 1, 0> {
  public:
   explicit LDeclareGlobals(LOperand* context) {
     inputs_[0] = context;
@@ -1819,7 +1838,7 @@ class LDeclareGlobals: public LTemplateInstruction<0, 1, 0> {
 };
 
 
-class LGlobalObject: public LTemplateInstruction<1, 1, 0> {
+class LGlobalObject V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LGlobalObject(LOperand* context) {
     inputs_[0] = context;
@@ -1831,7 +1850,7 @@ class LGlobalObject: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LGlobalReceiver: public LTemplateInstruction<1, 1, 0> {
+class LGlobalReceiver V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LGlobalReceiver(LOperand* global_object) {
     inputs_[0] = global_object;
@@ -1843,19 +1862,19 @@ class LGlobalReceiver: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LCallConstantFunction: public LTemplateInstruction<1, 0, 0> {
+class LCallConstantFunction V8_FINAL : public LTemplateInstruction<1, 0, 0> {
  public:
   DECLARE_CONCRETE_INSTRUCTION(CallConstantFunction, "call-constant-function")
   DECLARE_HYDROGEN_ACCESSOR(CallConstantFunction)
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
   Handle<JSFunction> function() { return hydrogen()->function(); }
   int arity() const { return hydrogen()->argument_count() - 1; }
 };
 
 
-class LInvokeFunction: public LTemplateInstruction<1, 2, 0> {
+class LInvokeFunction V8_FINAL : public LTemplateInstruction<1, 2, 0> {
  public:
   LInvokeFunction(LOperand* context, LOperand* function) {
     inputs_[0] = context;
@@ -1868,13 +1887,13 @@ class LInvokeFunction: public LTemplateInstruction<1, 2, 0> {
   DECLARE_CONCRETE_INSTRUCTION(InvokeFunction, "invoke-function")
   DECLARE_HYDROGEN_ACCESSOR(InvokeFunction)
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
   int arity() const { return hydrogen()->argument_count() - 1; }
 };
 
 
-class LCallKeyed: public LTemplateInstruction<1, 2, 0> {
+class LCallKeyed V8_FINAL : public LTemplateInstruction<1, 2, 0> {
  public:
   LCallKeyed(LOperand* context, LOperand* key) {
     inputs_[0] = context;
@@ -1887,13 +1906,13 @@ class LCallKeyed: public LTemplateInstruction<1, 2, 0> {
   DECLARE_CONCRETE_INSTRUCTION(CallKeyed, "call-keyed")
   DECLARE_HYDROGEN_ACCESSOR(CallKeyed)
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
   int arity() const { return hydrogen()->argument_count() - 1; }
 };
 
 
-class LCallNamed: public LTemplateInstruction<1, 1, 0> {
+class LCallNamed V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LCallNamed(LOperand* context) {
     inputs_[0] = context;
@@ -1904,14 +1923,14 @@ class LCallNamed: public LTemplateInstruction<1, 1, 0> {
   DECLARE_CONCRETE_INSTRUCTION(CallNamed, "call-named")
   DECLARE_HYDROGEN_ACCESSOR(CallNamed)
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
   Handle<String> name() const { return hydrogen()->name(); }
   int arity() const { return hydrogen()->argument_count() - 1; }
 };
 
 
-class LCallFunction: public LTemplateInstruction<1, 2, 0> {
+class LCallFunction V8_FINAL : public LTemplateInstruction<1, 2, 0> {
  public:
   explicit LCallFunction(LOperand* context, LOperand* function) {
     inputs_[0] = context;
@@ -1928,7 +1947,7 @@ class LCallFunction: public LTemplateInstruction<1, 2, 0> {
 };
 
 
-class LCallGlobal: public LTemplateInstruction<1, 1, 0> {
+class LCallGlobal V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LCallGlobal(LOperand* context) {
     inputs_[0] = context;
@@ -1939,25 +1958,25 @@ class LCallGlobal: public LTemplateInstruction<1, 1, 0> {
   DECLARE_CONCRETE_INSTRUCTION(CallGlobal, "call-global")
   DECLARE_HYDROGEN_ACCESSOR(CallGlobal)
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
   Handle<String> name() const {return hydrogen()->name(); }
   int arity() const { return hydrogen()->argument_count() - 1; }
 };
 
 
-class LCallKnownGlobal: public LTemplateInstruction<1, 0, 0> {
+class LCallKnownGlobal V8_FINAL : public LTemplateInstruction<1, 0, 0> {
  public:
   DECLARE_CONCRETE_INSTRUCTION(CallKnownGlobal, "call-known-global")
   DECLARE_HYDROGEN_ACCESSOR(CallKnownGlobal)
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
   int arity() const { return hydrogen()->argument_count() - 1;  }
 };
 
 
-class LCallNew: public LTemplateInstruction<1, 2, 0> {
+class LCallNew V8_FINAL : public LTemplateInstruction<1, 2, 0> {
  public:
   LCallNew(LOperand* context, LOperand* constructor) {
     inputs_[0] = context;
@@ -1970,13 +1989,13 @@ class LCallNew: public LTemplateInstruction<1, 2, 0> {
   DECLARE_CONCRETE_INSTRUCTION(CallNew, "call-new")
   DECLARE_HYDROGEN_ACCESSOR(CallNew)
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
   int arity() const { return hydrogen()->argument_count() - 1; }
 };
 
 
-class LCallNewArray: public LTemplateInstruction<1, 2, 0> {
+class LCallNewArray V8_FINAL : public LTemplateInstruction<1, 2, 0> {
  public:
   LCallNewArray(LOperand* context, LOperand* constructor) {
     inputs_[0] = context;
@@ -1989,13 +2008,13 @@ class LCallNewArray: public LTemplateInstruction<1, 2, 0> {
   DECLARE_CONCRETE_INSTRUCTION(CallNewArray, "call-new-array")
   DECLARE_HYDROGEN_ACCESSOR(CallNewArray)
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
   int arity() const { return hydrogen()->argument_count() - 1; }
 };
 
 
-class LCallRuntime: public LTemplateInstruction<1, 1, 0> {
+class LCallRuntime V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LCallRuntime(LOperand* context) {
     inputs_[0] = context;
@@ -2011,7 +2030,7 @@ class LCallRuntime: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LInteger32ToDouble: public LTemplateInstruction<1, 1, 0> {
+class LInteger32ToDouble V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LInteger32ToDouble(LOperand* value) {
     inputs_[0] = value;
@@ -2023,7 +2042,7 @@ class LInteger32ToDouble: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LInteger32ToSmi: public LTemplateInstruction<1, 1, 0> {
+class LInteger32ToSmi V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LInteger32ToSmi(LOperand* value) {
     inputs_[0] = value;
@@ -2036,7 +2055,7 @@ class LInteger32ToSmi: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LUint32ToDouble: public LTemplateInstruction<1, 1, 1> {
+class LUint32ToDouble V8_FINAL : public LTemplateInstruction<1, 1, 1> {
  public:
   explicit LUint32ToDouble(LOperand* value, LOperand* temp) {
     inputs_[0] = value;
@@ -2050,7 +2069,7 @@ class LUint32ToDouble: public LTemplateInstruction<1, 1, 1> {
 };
 
 
-class LNumberTagI: public LTemplateInstruction<1, 1, 0> {
+class LNumberTagI V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LNumberTagI(LOperand* value) {
     inputs_[0] = value;
@@ -2062,7 +2081,7 @@ class LNumberTagI: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LNumberTagU: public LTemplateInstruction<1, 1, 1> {
+class LNumberTagU V8_FINAL : public LTemplateInstruction<1, 1, 1> {
  public:
   LNumberTagU(LOperand* value, LOperand* temp) {
     inputs_[0] = value;
@@ -2076,7 +2095,7 @@ class LNumberTagU: public LTemplateInstruction<1, 1, 1> {
 };
 
 
-class LNumberTagD: public LTemplateInstruction<1, 1, 1> {
+class LNumberTagD V8_FINAL : public LTemplateInstruction<1, 1, 1> {
  public:
   LNumberTagD(LOperand* value, LOperand* temp) {
     inputs_[0] = value;
@@ -2092,7 +2111,7 @@ class LNumberTagD: public LTemplateInstruction<1, 1, 1> {
 
 
 // Sometimes truncating conversion from a tagged value to an int32.
-class LDoubleToI: public LTemplateInstruction<1, 1, 1> {
+class LDoubleToI V8_FINAL : public LTemplateInstruction<1, 1, 1> {
  public:
   LDoubleToI(LOperand* value, LOperand* temp) {
     inputs_[0] = value;
@@ -2109,7 +2128,7 @@ class LDoubleToI: public LTemplateInstruction<1, 1, 1> {
 };
 
 
-class LDoubleToSmi: public LTemplateInstruction<1, 1, 0> {
+class LDoubleToSmi V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LDoubleToSmi(LOperand* value) {
     inputs_[0] = value;
@@ -2123,7 +2142,7 @@ class LDoubleToSmi: public LTemplateInstruction<1, 1, 0> {
 
 
 // Truncating conversion from a tagged value to an int32.
-class LTaggedToI: public LTemplateInstruction<1, 1, 1> {
+class LTaggedToI V8_FINAL : public LTemplateInstruction<1, 1, 1> {
  public:
   LTaggedToI(LOperand* value, LOperand* temp) {
     inputs_[0] = value;
@@ -2141,7 +2160,7 @@ class LTaggedToI: public LTemplateInstruction<1, 1, 1> {
 
 
 // Truncating conversion from a tagged value to an int32.
-class LTaggedToINoSSE2: public LTemplateInstruction<1, 1, 3> {
+class LTaggedToINoSSE2 V8_FINAL : public LTemplateInstruction<1, 1, 3> {
  public:
   LTaggedToINoSSE2(LOperand* value,
                    LOperand* temp1,
@@ -2165,7 +2184,7 @@ class LTaggedToINoSSE2: public LTemplateInstruction<1, 1, 3> {
 };
 
 
-class LSmiTag: public LTemplateInstruction<1, 1, 0> {
+class LSmiTag V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LSmiTag(LOperand* value) {
     inputs_[0] = value;
@@ -2177,7 +2196,7 @@ class LSmiTag: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LNumberUntagD: public LTemplateInstruction<1, 1, 1> {
+class LNumberUntagD V8_FINAL : public LTemplateInstruction<1, 1, 1> {
  public:
   explicit LNumberUntagD(LOperand* value, LOperand* temp) {
     inputs_[0] = value;
@@ -2187,14 +2206,14 @@ class LNumberUntagD: public LTemplateInstruction<1, 1, 1> {
   LOperand* value() { return inputs_[0]; }
   LOperand* temp() { return temps_[0]; }
 
-  virtual bool ClobbersDoubleRegisters() const { return false; }
+  virtual bool ClobbersDoubleRegisters() const V8_OVERRIDE { return false; }
 
   DECLARE_CONCRETE_INSTRUCTION(NumberUntagD, "double-untag")
   DECLARE_HYDROGEN_ACCESSOR(Change);
 };
 
 
-class LSmiUntag: public LTemplateInstruction<1, 1, 0> {
+class LSmiUntag V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   LSmiUntag(LOperand* value, bool needs_check)
       : needs_check_(needs_check) {
@@ -2212,7 +2231,7 @@ class LSmiUntag: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LStoreNamedField: public LTemplateInstruction<0, 2, 2> {
+class LStoreNamedField V8_FINAL : public LTemplateInstruction<0, 2, 2> {
  public:
   LStoreNamedField(LOperand* obj,
                    LOperand* val,
@@ -2232,7 +2251,7 @@ class LStoreNamedField: public LTemplateInstruction<0, 2, 2> {
   DECLARE_CONCRETE_INSTRUCTION(StoreNamedField, "store-named-field")
   DECLARE_HYDROGEN_ACCESSOR(StoreNamedField)
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
   Handle<Map> transition() const { return hydrogen()->transition_map(); }
   Representation representation() const {
@@ -2241,7 +2260,7 @@ class LStoreNamedField: public LTemplateInstruction<0, 2, 2> {
 };
 
 
-class LStoreNamedGeneric: public LTemplateInstruction<0, 3, 0> {
+class LStoreNamedGeneric V8_FINAL : public LTemplateInstruction<0, 3, 0> {
  public:
   LStoreNamedGeneric(LOperand* context, LOperand* object, LOperand* value) {
     inputs_[0] = context;
@@ -2256,13 +2275,13 @@ class LStoreNamedGeneric: public LTemplateInstruction<0, 3, 0> {
   DECLARE_CONCRETE_INSTRUCTION(StoreNamedGeneric, "store-named-generic")
   DECLARE_HYDROGEN_ACCESSOR(StoreNamedGeneric)
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
   Handle<Object> name() const { return hydrogen()->name(); }
   StrictModeFlag strict_mode_flag() { return hydrogen()->strict_mode_flag(); }
 };
 
 
-class LStoreKeyed: public LTemplateInstruction<0, 3, 0> {
+class LStoreKeyed V8_FINAL : public LTemplateInstruction<0, 3, 0> {
  public:
   LStoreKeyed(LOperand* obj, LOperand* key, LOperand* val) {
     inputs_[0] = obj;
@@ -2281,13 +2300,13 @@ class LStoreKeyed: public LTemplateInstruction<0, 3, 0> {
   DECLARE_CONCRETE_INSTRUCTION(StoreKeyed, "store-keyed")
   DECLARE_HYDROGEN_ACCESSOR(StoreKeyed)
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
   uint32_t additional_index() const { return hydrogen()->index_offset(); }
   bool NeedsCanonicalization() { return hydrogen()->NeedsCanonicalization(); }
 };
 
 
-class LStoreKeyedGeneric: public LTemplateInstruction<0, 4, 0> {
+class LStoreKeyedGeneric V8_FINAL : public LTemplateInstruction<0, 4, 0> {
  public:
   LStoreKeyedGeneric(LOperand* context,
                      LOperand* object,
@@ -2307,13 +2326,13 @@ class LStoreKeyedGeneric: public LTemplateInstruction<0, 4, 0> {
   DECLARE_CONCRETE_INSTRUCTION(StoreKeyedGeneric, "store-keyed-generic")
   DECLARE_HYDROGEN_ACCESSOR(StoreKeyedGeneric)
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
   StrictModeFlag strict_mode_flag() { return hydrogen()->strict_mode_flag(); }
 };
 
 
-class LTransitionElementsKind: public LTemplateInstruction<0, 2, 2> {
+class LTransitionElementsKind V8_FINAL : public LTemplateInstruction<0, 2, 2> {
  public:
   LTransitionElementsKind(LOperand* object,
                           LOperand* context,
@@ -2334,7 +2353,7 @@ class LTransitionElementsKind: public LTemplateInstruction<0, 2, 2> {
                                "transition-elements-kind")
   DECLARE_HYDROGEN_ACCESSOR(TransitionElementsKind)
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
   Handle<Map> original_map() { return hydrogen()->original_map(); }
   Handle<Map> transitioned_map() { return hydrogen()->transitioned_map(); }
@@ -2343,7 +2362,7 @@ class LTransitionElementsKind: public LTemplateInstruction<0, 2, 2> {
 };
 
 
-class LTrapAllocationMemento : public LTemplateInstruction<0, 1, 1> {
+class LTrapAllocationMemento V8_FINAL  : public LTemplateInstruction<0, 1, 1> {
  public:
   LTrapAllocationMemento(LOperand* object,
                          LOperand* temp) {
@@ -2359,7 +2378,7 @@ class LTrapAllocationMemento : public LTemplateInstruction<0, 1, 1> {
 };
 
 
-class LStringAdd: public LTemplateInstruction<1, 3, 0> {
+class LStringAdd V8_FINAL : public LTemplateInstruction<1, 3, 0> {
  public:
   LStringAdd(LOperand* context, LOperand* left, LOperand* right) {
     inputs_[0] = context;
@@ -2376,7 +2395,7 @@ class LStringAdd: public LTemplateInstruction<1, 3, 0> {
 };
 
 
-class LStringCharCodeAt: public LTemplateInstruction<1, 3, 0> {
+class LStringCharCodeAt V8_FINAL : public LTemplateInstruction<1, 3, 0> {
  public:
   LStringCharCodeAt(LOperand* context, LOperand* string, LOperand* index) {
     inputs_[0] = context;
@@ -2393,7 +2412,7 @@ class LStringCharCodeAt: public LTemplateInstruction<1, 3, 0> {
 };
 
 
-class LStringCharFromCode: public LTemplateInstruction<1, 2, 0> {
+class LStringCharFromCode V8_FINAL : public LTemplateInstruction<1, 2, 0> {
  public:
   LStringCharFromCode(LOperand* context, LOperand* char_code) {
     inputs_[0] = context;
@@ -2408,7 +2427,7 @@ class LStringCharFromCode: public LTemplateInstruction<1, 2, 0> {
 };
 
 
-class LCheckFunction: public LTemplateInstruction<0, 1, 0> {
+class LCheckFunction V8_FINAL : public LTemplateInstruction<0, 1, 0> {
  public:
   explicit LCheckFunction(LOperand* value) {
     inputs_[0] = value;
@@ -2421,7 +2440,7 @@ class LCheckFunction: public LTemplateInstruction<0, 1, 0> {
 };
 
 
-class LCheckInstanceType: public LTemplateInstruction<0, 1, 1> {
+class LCheckInstanceType V8_FINAL : public LTemplateInstruction<0, 1, 1> {
  public:
   LCheckInstanceType(LOperand* value, LOperand* temp) {
     inputs_[0] = value;
@@ -2436,7 +2455,7 @@ class LCheckInstanceType: public LTemplateInstruction<0, 1, 1> {
 };
 
 
-class LCheckMaps: public LTemplateInstruction<0, 1, 0> {
+class LCheckMaps V8_FINAL : public LTemplateInstruction<0, 1, 0> {
  public:
   explicit LCheckMaps(LOperand* value) {
     inputs_[0] = value;
@@ -2449,7 +2468,7 @@ class LCheckMaps: public LTemplateInstruction<0, 1, 0> {
 };
 
 
-class LCheckSmi: public LTemplateInstruction<1, 1, 0> {
+class LCheckSmi V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LCheckSmi(LOperand* value) {
     inputs_[0] = value;
@@ -2461,7 +2480,7 @@ class LCheckSmi: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LClampDToUint8: public LTemplateInstruction<1, 1, 0> {
+class LClampDToUint8 V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LClampDToUint8(LOperand* value) {
     inputs_[0] = value;
@@ -2473,7 +2492,7 @@ class LClampDToUint8: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LClampIToUint8: public LTemplateInstruction<1, 1, 0> {
+class LClampIToUint8 V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LClampIToUint8(LOperand* value) {
     inputs_[0] = value;
@@ -2485,7 +2504,7 @@ class LClampIToUint8: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LClampTToUint8: public LTemplateInstruction<1, 1, 1> {
+class LClampTToUint8 V8_FINAL : public LTemplateInstruction<1, 1, 1> {
  public:
   LClampTToUint8(LOperand* value, LOperand* temp) {
     inputs_[0] = value;
@@ -2499,7 +2518,7 @@ class LClampTToUint8: public LTemplateInstruction<1, 1, 1> {
 
 
 // Truncating conversion from a tagged value to an int32.
-class LClampTToUint8NoSSE2: public LTemplateInstruction<1, 1, 3> {
+class LClampTToUint8NoSSE2 V8_FINAL : public LTemplateInstruction<1, 1, 3> {
  public:
   LClampTToUint8NoSSE2(LOperand* unclamped,
                        LOperand* temp1,
@@ -2522,7 +2541,7 @@ class LClampTToUint8NoSSE2: public LTemplateInstruction<1, 1, 3> {
 };
 
 
-class LCheckNonSmi: public LTemplateInstruction<0, 1, 0> {
+class LCheckNonSmi V8_FINAL : public LTemplateInstruction<0, 1, 0> {
  public:
   explicit LCheckNonSmi(LOperand* value) {
     inputs_[0] = value;
@@ -2535,7 +2554,7 @@ class LCheckNonSmi: public LTemplateInstruction<0, 1, 0> {
 };
 
 
-class LAllocate: public LTemplateInstruction<1, 2, 1> {
+class LAllocate V8_FINAL : public LTemplateInstruction<1, 2, 1> {
  public:
   LAllocate(LOperand* context, LOperand* size, LOperand* temp) {
     inputs_[0] = context;
@@ -2552,7 +2571,7 @@ class LAllocate: public LTemplateInstruction<1, 2, 1> {
 };
 
 
-class LRegExpLiteral: public LTemplateInstruction<1, 1, 0> {
+class LRegExpLiteral V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LRegExpLiteral(LOperand* context) {
     inputs_[0] = context;
@@ -2565,7 +2584,7 @@ class LRegExpLiteral: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LFunctionLiteral: public LTemplateInstruction<1, 1, 0> {
+class LFunctionLiteral V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LFunctionLiteral(LOperand* context) {
     inputs_[0] = context;
@@ -2578,7 +2597,7 @@ class LFunctionLiteral: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LToFastProperties: public LTemplateInstruction<1, 1, 0> {
+class LToFastProperties V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LToFastProperties(LOperand* value) {
     inputs_[0] = value;
@@ -2591,7 +2610,7 @@ class LToFastProperties: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LTypeof: public LTemplateInstruction<1, 2, 0> {
+class LTypeof V8_FINAL : public LTemplateInstruction<1, 2, 0> {
  public:
   LTypeof(LOperand* context, LOperand* value) {
     inputs_[0] = context;
@@ -2605,7 +2624,7 @@ class LTypeof: public LTemplateInstruction<1, 2, 0> {
 };
 
 
-class LTypeofIsAndBranch: public LControlInstruction<1, 0> {
+class LTypeofIsAndBranch V8_FINAL : public LControlInstruction<1, 0> {
  public:
   explicit LTypeofIsAndBranch(LOperand* value) {
     inputs_[0] = value;
@@ -2618,20 +2637,20 @@ class LTypeofIsAndBranch: public LControlInstruction<1, 0> {
 
   Handle<String> type_literal() { return hydrogen()->type_literal(); }
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 };
 
 
-class LOsrEntry: public LTemplateInstruction<0, 0, 0> {
+class LOsrEntry V8_FINAL : public LTemplateInstruction<0, 0, 0> {
  public:
-  LOsrEntry() {}
-
-  virtual bool HasInterestingComment(LCodeGen* gen) const { return false; }
+  virtual bool HasInterestingComment(LCodeGen* gen) const V8_OVERRIDE {
+    return false;
+  }
   DECLARE_CONCRETE_INSTRUCTION(OsrEntry, "osr-entry")
 };
 
 
-class LStackCheck: public LTemplateInstruction<0, 1, 0> {
+class LStackCheck V8_FINAL : public LTemplateInstruction<0, 1, 0> {
  public:
   explicit LStackCheck(LOperand* context) {
     inputs_[0] = context;
@@ -2649,7 +2668,7 @@ class LStackCheck: public LTemplateInstruction<0, 1, 0> {
 };
 
 
-class LForInPrepareMap: public LTemplateInstruction<1, 2, 0> {
+class LForInPrepareMap V8_FINAL : public LTemplateInstruction<1, 2, 0> {
  public:
   LForInPrepareMap(LOperand* context, LOperand* object) {
     inputs_[0] = context;
@@ -2663,7 +2682,7 @@ class LForInPrepareMap: public LTemplateInstruction<1, 2, 0> {
 };
 
 
-class LForInCacheArray: public LTemplateInstruction<1, 1, 0> {
+class LForInCacheArray V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LForInCacheArray(LOperand* map) {
     inputs_[0] = map;
@@ -2679,7 +2698,7 @@ class LForInCacheArray: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LCheckMapValue: public LTemplateInstruction<0, 2, 0> {
+class LCheckMapValue V8_FINAL : public LTemplateInstruction<0, 2, 0> {
  public:
   LCheckMapValue(LOperand* value, LOperand* map) {
     inputs_[0] = value;
@@ -2693,7 +2712,7 @@ class LCheckMapValue: public LTemplateInstruction<0, 2, 0> {
 };
 
 
-class LLoadFieldByIndex: public LTemplateInstruction<1, 2, 0> {
+class LLoadFieldByIndex V8_FINAL : public LTemplateInstruction<1, 2, 0> {
  public:
   LLoadFieldByIndex(LOperand* object, LOperand* index) {
     inputs_[0] = object;
@@ -2708,7 +2727,7 @@ class LLoadFieldByIndex: public LTemplateInstruction<1, 2, 0> {
 
 
 class LChunkBuilder;
-class LPlatformChunk: public LChunk {
+class LPlatformChunk V8_FINAL : public LChunk {
  public:
   LPlatformChunk(CompilationInfo* info, HGraph* graph)
       : LChunk(info, graph),
@@ -2724,7 +2743,7 @@ class LPlatformChunk: public LChunk {
 };
 
 
-class LChunkBuilder BASE_EMBEDDED {
+class LChunkBuilder V8_FINAL BASE_EMBEDDED {
  public:
   LChunkBuilder(CompilationInfo* info, HGraph* graph, LAllocator* allocator)
       : chunk_(NULL),
diff --git a/src/lithium.h b/src/lithium.h
index f773916485..fd50ee8f8b 100644
--- a/src/lithium.h
+++ b/src/lithium.h
@@ -43,7 +43,7 @@ namespace internal {
   V(DoubleRegister,  DOUBLE_REGISTER)
 
 
-class LOperand: public ZoneObject {
+class LOperand : public ZoneObject {
  public:
   enum Kind {
     INVALID,
@@ -90,7 +90,7 @@ class LOperand: public ZoneObject {
 };
 
 
-class LUnallocated: public LOperand {
+class LUnallocated : public LOperand {
  public:
   enum BasicPolicy {
     FIXED_SLOT,
@@ -271,7 +271,7 @@ class LUnallocated: public LOperand {
 };
 
 
-class LMoveOperands BASE_EMBEDDED {
+class LMoveOperands V8_FINAL BASE_EMBEDDED {
  public:
   LMoveOperands(LOperand* source, LOperand* destination)
       : source_(source), destination_(destination) {
@@ -317,7 +317,7 @@ class LMoveOperands BASE_EMBEDDED {
 };
 
 
-class LConstantOperand: public LOperand {
+class LConstantOperand V8_FINAL : public LOperand {
  public:
   static LConstantOperand* Create(int index, Zone* zone) {
     ASSERT(index >= 0);
@@ -342,7 +342,7 @@ class LConstantOperand: public LOperand {
 };
 
 
-class LArgument: public LOperand {
+class LArgument V8_FINAL : public LOperand {
  public:
   explicit LArgument(int index) : LOperand(ARGUMENT, index) { }
 
@@ -353,7 +353,7 @@ class LArgument: public LOperand {
 };
 
 
-class LStackSlot: public LOperand {
+class LStackSlot V8_FINAL : public LOperand {
  public:
   static LStackSlot* Create(int index, Zone* zone) {
     ASSERT(index >= 0);
@@ -378,7 +378,7 @@ class LStackSlot: public LOperand {
 };
 
 
-class LDoubleStackSlot: public LOperand {
+class LDoubleStackSlot V8_FINAL : public LOperand {
  public:
   static LDoubleStackSlot* Create(int index, Zone* zone) {
     ASSERT(index >= 0);
@@ -403,7 +403,7 @@ class LDoubleStackSlot: public LOperand {
 };
 
 
-class LRegister: public LOperand {
+class LRegister V8_FINAL : public LOperand {
  public:
   static LRegister* Create(int index, Zone* zone) {
     ASSERT(index >= 0);
@@ -428,7 +428,7 @@ class LRegister: public LOperand {
 };
 
 
-class LDoubleRegister: public LOperand {
+class LDoubleRegister V8_FINAL : public LOperand {
  public:
   static LDoubleRegister* Create(int index, Zone* zone) {
     ASSERT(index >= 0);
@@ -453,7 +453,7 @@ class LDoubleRegister: public LOperand {
 };
 
 
-class LParallelMove : public ZoneObject {
+class LParallelMove V8_FINAL : public ZoneObject {
  public:
   explicit LParallelMove(Zone* zone) : move_operands_(4, zone) { }
 
@@ -474,7 +474,7 @@ class LParallelMove : public ZoneObject {
 };
 
 
-class LPointerMap: public ZoneObject {
+class LPointerMap V8_FINAL : public ZoneObject {
  public:
   explicit LPointerMap(int position, Zone* zone)
       : pointer_operands_(8, zone),
@@ -510,7 +510,7 @@ class LPointerMap: public ZoneObject {
 };
 
 
-class LEnvironment: public ZoneObject {
+class LEnvironment V8_FINAL : public ZoneObject {
  public:
   LEnvironment(Handle<JSFunction> closure,
                FrameType frame_type,
@@ -655,7 +655,7 @@ class LEnvironment: public ZoneObject {
 
 
 // Iterates over the non-null, non-constant operands in an environment.
-class ShallowIterator BASE_EMBEDDED {
+class ShallowIterator V8_FINAL BASE_EMBEDDED {
  public:
   explicit ShallowIterator(LEnvironment* env)
       : env_(env),
@@ -699,7 +699,7 @@ class ShallowIterator BASE_EMBEDDED {
 
 
 // Iterator for non-null, non-constant operands incl. outer environments.
-class DeepIterator BASE_EMBEDDED {
+class DeepIterator V8_FINAL BASE_EMBEDDED {
  public:
   explicit DeepIterator(LEnvironment* env)
       : current_iterator_(env) {
@@ -736,7 +736,7 @@ class LLabel;
 
 // Superclass providing data and behavior common to all the
 // arch-specific LPlatformChunk classes.
-class LChunk: public ZoneObject {
+class LChunk : public ZoneObject {
  public:
   static LChunk* NewChunk(HGraph* graph);
 
diff --git a/src/mips/lithium-codegen-mips.cc b/src/mips/lithium-codegen-mips.cc
index 7dd7fd93c3..aa56d7298e 100644
--- a/src/mips/lithium-codegen-mips.cc
+++ b/src/mips/lithium-codegen-mips.cc
@@ -36,7 +36,7 @@ namespace v8 {
 namespace internal {
 
 
-class SafepointGenerator : public CallWrapper {
+class SafepointGenerator V8_FINAL  : public CallWrapper {
  public:
   SafepointGenerator(LCodeGen* codegen,
                      LPointerMap* pointers,
@@ -44,11 +44,11 @@ class SafepointGenerator : public CallWrapper {
       : codegen_(codegen),
         pointers_(pointers),
         deopt_mode_(mode) { }
-  virtual ~SafepointGenerator() { }
+  virtual ~SafepointGenerator() {}
 
-  virtual void BeforeCall(int call_size) const { }
+  virtual void BeforeCall(int call_size) const V8_OVERRIDE {}
 
-  virtual void AfterCall() const {
+  virtual void AfterCall() const V8_OVERRIDE {
     codegen_->RecordSafepoint(pointers_, deopt_mode_);
   }
 
@@ -2605,15 +2605,15 @@ void LCodeGen::DoInstanceOf(LInstanceOf* instr) {
 
 
 void LCodeGen::DoInstanceOfKnownGlobal(LInstanceOfKnownGlobal* instr) {
-  class DeferredInstanceOfKnownGlobal: public LDeferredCode {
+  class DeferredInstanceOfKnownGlobal V8_FINAL : public LDeferredCode {
    public:
     DeferredInstanceOfKnownGlobal(LCodeGen* codegen,
                                   LInstanceOfKnownGlobal* instr)
         : LDeferredCode(codegen), instr_(instr) { }
-    virtual void Generate() {
+    virtual void Generate() V8_OVERRIDE {
       codegen()->DoDeferredInstanceOfKnownGlobal(instr_, &map_check_);
     }
-    virtual LInstruction* instr() { return instr_; }
+    virtual LInstruction* instr() V8_OVERRIDE { return instr_; }
     Label* map_check() { return &map_check_; }
 
    private:
@@ -3599,14 +3599,14 @@ void LCodeGen::EmitIntegerMathAbs(LMathAbs* instr) {
 
 void LCodeGen::DoMathAbs(LMathAbs* instr) {
   // Class for deferred case.
-  class DeferredMathAbsTaggedHeapNumber: public LDeferredCode {
+  class DeferredMathAbsTaggedHeapNumber V8_FINAL : public LDeferredCode {
    public:
     DeferredMathAbsTaggedHeapNumber(LCodeGen* codegen, LMathAbs* instr)
         : LDeferredCode(codegen), instr_(instr) { }
-    virtual void Generate() {
+    virtual void Generate() V8_OVERRIDE {
       codegen()->DoDeferredMathAbsTaggedHeapNumber(instr_);
     }
-    virtual LInstruction* instr() { return instr_; }
+    virtual LInstruction* instr() V8_OVERRIDE { return instr_; }
    private:
     LMathAbs* instr_;
   };
@@ -3801,12 +3801,12 @@ void LCodeGen::DoPower(LPower* instr) {
 
 
 void LCodeGen::DoRandom(LRandom* instr) {
-  class DeferredDoRandom: public LDeferredCode {
+  class DeferredDoRandom V8_FINAL : public LDeferredCode {
    public:
     DeferredDoRandom(LCodeGen* codegen, LRandom* instr)
         : LDeferredCode(codegen), instr_(instr) { }
-    virtual void Generate() { codegen()->DoDeferredRandom(instr_); }
-    virtual LInstruction* instr() { return instr_; }
+    virtual void Generate() V8_OVERRIDE { codegen()->DoDeferredRandom(instr_); }
+    virtual LInstruction* instr() V8_OVERRIDE { return instr_; }
    private:
     LRandom* instr_;
   };
@@ -4461,12 +4461,14 @@ void LCodeGen::DoStringAdd(LStringAdd* instr) {
 
 
 void LCodeGen::DoStringCharCodeAt(LStringCharCodeAt* instr) {
-  class DeferredStringCharCodeAt: public LDeferredCode {
+  class DeferredStringCharCodeAt V8_FINAL : public LDeferredCode {
    public:
     DeferredStringCharCodeAt(LCodeGen* codegen, LStringCharCodeAt* instr)
         : LDeferredCode(codegen), instr_(instr) { }
-    virtual void Generate() { codegen()->DoDeferredStringCharCodeAt(instr_); }
-    virtual LInstruction* instr() { return instr_; }
+    virtual void Generate() V8_OVERRIDE {
+      codegen()->DoDeferredStringCharCodeAt(instr_);
+    }
+    virtual LInstruction* instr() V8_OVERRIDE { return instr_; }
    private:
     LStringCharCodeAt* instr_;
   };
@@ -4513,12 +4515,14 @@ void LCodeGen::DoDeferredStringCharCodeAt(LStringCharCodeAt* instr) {
 
 
 void LCodeGen::DoStringCharFromCode(LStringCharFromCode* instr) {
-  class DeferredStringCharFromCode: public LDeferredCode {
+  class DeferredStringCharFromCode V8_FINAL : public LDeferredCode {
    public:
     DeferredStringCharFromCode(LCodeGen* codegen, LStringCharFromCode* instr)
         : LDeferredCode(codegen), instr_(instr) { }
-    virtual void Generate() { codegen()->DoDeferredStringCharFromCode(instr_); }
-    virtual LInstruction* instr() { return instr_; }
+    virtual void Generate() V8_OVERRIDE {
+      codegen()->DoDeferredStringCharFromCode(instr_);
+    }
+    virtual LInstruction* instr() V8_OVERRIDE { return instr_; }
    private:
     LStringCharFromCode* instr_;
   };
@@ -4604,16 +4608,16 @@ void LCodeGen::DoUint32ToDouble(LUint32ToDouble* instr) {
 
 
 void LCodeGen::DoNumberTagI(LNumberTagI* instr) {
-  class DeferredNumberTagI: public LDeferredCode {
+  class DeferredNumberTagI V8_FINAL : public LDeferredCode {
    public:
     DeferredNumberTagI(LCodeGen* codegen, LNumberTagI* instr)
         : LDeferredCode(codegen), instr_(instr) { }
-    virtual void Generate() {
+    virtual void Generate() V8_OVERRIDE {
       codegen()->DoDeferredNumberTagI(instr_,
                                       instr_->value(),
                                       SIGNED_INT32);
     }
-    virtual LInstruction* instr() { return instr_; }
+    virtual LInstruction* instr() V8_OVERRIDE { return instr_; }
    private:
     LNumberTagI* instr_;
   };
@@ -4630,16 +4634,16 @@ void LCodeGen::DoNumberTagI(LNumberTagI* instr) {
 
 
 void LCodeGen::DoNumberTagU(LNumberTagU* instr) {
-  class DeferredNumberTagU: public LDeferredCode {
+  class DeferredNumberTagU V8_FINAL : public LDeferredCode {
    public:
     DeferredNumberTagU(LCodeGen* codegen, LNumberTagU* instr)
         : LDeferredCode(codegen), instr_(instr) { }
-    virtual void Generate() {
+    virtual void Generate() V8_OVERRIDE {
       codegen()->DoDeferredNumberTagI(instr_,
                                       instr_->value(),
                                       UNSIGNED_INT32);
     }
-    virtual LInstruction* instr() { return instr_; }
+    virtual LInstruction* instr() V8_OVERRIDE { return instr_; }
    private:
     LNumberTagU* instr_;
   };
@@ -4710,12 +4714,14 @@ void LCodeGen::DoDeferredNumberTagI(LInstruction* instr,
 
 
 void LCodeGen::DoNumberTagD(LNumberTagD* instr) {
-  class DeferredNumberTagD: public LDeferredCode {
+  class DeferredNumberTagD V8_FINAL : public LDeferredCode {
    public:
     DeferredNumberTagD(LCodeGen* codegen, LNumberTagD* instr)
         : LDeferredCode(codegen), instr_(instr) { }
-    virtual void Generate() { codegen()->DoDeferredNumberTagD(instr_); }
-    virtual LInstruction* instr() { return instr_; }
+    virtual void Generate() V8_OVERRIDE {
+      codegen()->DoDeferredNumberTagD(instr_);
+    }
+    virtual LInstruction* instr() V8_OVERRIDE { return instr_; }
    private:
     LNumberTagD* instr_;
   };
@@ -4914,12 +4920,14 @@ void LCodeGen::DoDeferredTaggedToI(LTaggedToI* instr) {
 
 
 void LCodeGen::DoTaggedToI(LTaggedToI* instr) {
-  class DeferredTaggedToI: public LDeferredCode {
+  class DeferredTaggedToI V8_FINAL : public LDeferredCode {
    public:
     DeferredTaggedToI(LCodeGen* codegen, LTaggedToI* instr)
         : LDeferredCode(codegen), instr_(instr) { }
-    virtual void Generate() { codegen()->DoDeferredTaggedToI(instr_); }
-    virtual LInstruction* instr() { return instr_; }
+    virtual void Generate() V8_OVERRIDE {
+      codegen()->DoDeferredTaggedToI(instr_);
+    }
+    virtual LInstruction* instr() V8_OVERRIDE { return instr_; }
    private:
     LTaggedToI* instr_;
   };
@@ -5132,17 +5140,17 @@ void LCodeGen::DoDeferredInstanceMigration(LCheckMaps* instr, Register object) {
 
 
 void LCodeGen::DoCheckMaps(LCheckMaps* instr) {
-  class DeferredCheckMaps: public LDeferredCode {
+  class DeferredCheckMaps V8_FINAL : public LDeferredCode {
    public:
     DeferredCheckMaps(LCodeGen* codegen, LCheckMaps* instr, Register object)
         : LDeferredCode(codegen), instr_(instr), object_(object) {
       SetExit(check_maps());
     }
-    virtual void Generate() {
+    virtual void Generate() V8_OVERRIDE {
       codegen()->DoDeferredInstanceMigration(instr_, object_);
     }
     Label* check_maps() { return &check_maps_; }
-    virtual LInstruction* instr() { return instr_; }
+    virtual LInstruction* instr() V8_OVERRIDE { return instr_; }
    private:
     LCheckMaps* instr_;
     Label check_maps_;
@@ -5231,12 +5239,14 @@ void LCodeGen::DoClampTToUint8(LClampTToUint8* instr) {
 
 
 void LCodeGen::DoAllocate(LAllocate* instr) {
-  class DeferredAllocate: public LDeferredCode {
+  class DeferredAllocate V8_FINAL : public LDeferredCode {
    public:
     DeferredAllocate(LCodeGen* codegen, LAllocate* instr)
         : LDeferredCode(codegen), instr_(instr) { }
-    virtual void Generate() { codegen()->DoDeferredAllocate(instr_); }
-    virtual LInstruction* instr() { return instr_; }
+    virtual void Generate() V8_OVERRIDE {
+      codegen()->DoDeferredAllocate(instr_);
+    }
+    virtual LInstruction* instr() V8_OVERRIDE { return instr_; }
    private:
     LAllocate* instr_;
   };
@@ -5633,12 +5643,14 @@ void LCodeGen::DoDeferredStackCheck(LStackCheck* instr) {
 
 
 void LCodeGen::DoStackCheck(LStackCheck* instr) {
-  class DeferredStackCheck: public LDeferredCode {
+  class DeferredStackCheck V8_FINAL : public LDeferredCode {
    public:
     DeferredStackCheck(LCodeGen* codegen, LStackCheck* instr)
         : LDeferredCode(codegen), instr_(instr) { }
-    virtual void Generate() { codegen()->DoDeferredStackCheck(instr_); }
-    virtual LInstruction* instr() { return instr_; }
+    virtual void Generate() V8_OVERRIDE {
+      codegen()->DoDeferredStackCheck(instr_);
+    }
+    virtual LInstruction* instr() V8_OVERRIDE { return instr_; }
    private:
     LStackCheck* instr_;
   };
diff --git a/src/mips/lithium-codegen-mips.h b/src/mips/lithium-codegen-mips.h
index f0f44e7d53..13b58040bd 100644
--- a/src/mips/lithium-codegen-mips.h
+++ b/src/mips/lithium-codegen-mips.h
@@ -42,7 +42,7 @@ namespace internal {
 class LDeferredCode;
 class SafepointGenerator;
 
-class LCodeGen BASE_EMBEDDED {
+class LCodeGen V8_FINAL  BASE_EMBEDDED {
  public:
   LCodeGen(LChunk* chunk, MacroAssembler* assembler, CompilationInfo* info)
       : zone_(info->zone()),
@@ -441,7 +441,7 @@ class LCodeGen BASE_EMBEDDED {
 
   int old_position_;
 
-  class PushSafepointRegistersScope BASE_EMBEDDED {
+  class PushSafepointRegistersScope V8_FINAL  BASE_EMBEDDED {
    public:
     PushSafepointRegistersScope(LCodeGen* codegen,
                                 Safepoint::Kind kind)
@@ -489,7 +489,7 @@ class LCodeGen BASE_EMBEDDED {
 };
 
 
-class LDeferredCode: public ZoneObject {
+class LDeferredCode : public ZoneObject {
  public:
   explicit LDeferredCode(LCodeGen* codegen)
       : codegen_(codegen),
@@ -498,7 +498,7 @@ class LDeferredCode: public ZoneObject {
     codegen->AddDeferredCode(this);
   }
 
-  virtual ~LDeferredCode() { }
+  virtual ~LDeferredCode() {}
   virtual void Generate() = 0;
   virtual LInstruction* instr() = 0;
 
diff --git a/src/mips/lithium-gap-resolver-mips.h b/src/mips/lithium-gap-resolver-mips.h
index 2506e38c35..ea1ea3cbbf 100644
--- a/src/mips/lithium-gap-resolver-mips.h
+++ b/src/mips/lithium-gap-resolver-mips.h
@@ -38,7 +38,7 @@ namespace internal {
 class LCodeGen;
 class LGapResolver;
 
-class LGapResolver BASE_EMBEDDED {
+class LGapResolver V8_FINAL BASE_EMBEDDED {
  public:
   explicit LGapResolver(LCodeGen* owner);
 
diff --git a/src/mips/lithium-mips.h b/src/mips/lithium-mips.h
index 4bf904970e..479f75aff3 100644
--- a/src/mips/lithium-mips.h
+++ b/src/mips/lithium-mips.h
@@ -186,13 +186,17 @@ class LCodeGen;
   V(ValueOf)                                    \
   V(WrapReceiver)
 
-#define DECLARE_CONCRETE_INSTRUCTION(type, mnemonic)              \
-  virtual Opcode opcode() const { return LInstruction::k##type; } \
-  virtual void CompileToNative(LCodeGen* generator);              \
-  virtual const char* Mnemonic() const { return mnemonic; }       \
-  static L##type* cast(LInstruction* instr) {                     \
-    ASSERT(instr->Is##type());                                    \
-    return reinterpret_cast<L##type*>(instr);                     \
+#define DECLARE_CONCRETE_INSTRUCTION(type, mnemonic)                        \
+  virtual Opcode opcode() const V8_FINAL V8_OVERRIDE {                      \
+    return LInstruction::k##type;                                           \
+  }                                                                         \
+  virtual void CompileToNative(LCodeGen* generator) V8_FINAL V8_OVERRIDE;   \
+  virtual const char* Mnemonic() const V8_FINAL V8_OVERRIDE {               \
+    return mnemonic;                                                        \
+  }                                                                         \
+  static L##type* cast(LInstruction* instr) {                               \
+    ASSERT(instr->Is##type());                                              \
+    return reinterpret_cast<L##type*>(instr);                               \
   }
 
 
@@ -202,7 +206,7 @@ class LCodeGen;
   }
 
 
-class LInstruction: public ZoneObject {
+class LInstruction : public ZoneObject {
  public:
   LInstruction()
       : environment_(NULL),
@@ -211,7 +215,7 @@ class LInstruction: public ZoneObject {
     set_position(RelocInfo::kNoPosition);
   }
 
-  virtual ~LInstruction() { }
+  virtual ~LInstruction() {}
 
   virtual void CompileToNative(LCodeGen* generator) = 0;
   virtual const char* Mnemonic() const = 0;
@@ -310,11 +314,13 @@ class LInstruction: public ZoneObject {
 // I = number of input operands.
 // T = number of temporary operands.
 template<int R, int I, int T>
-class LTemplateInstruction: public LInstruction {
+class LTemplateInstruction : public LInstruction {
  public:
   // Allow 0 or 1 output operands.
   STATIC_ASSERT(R == 0 || R == 1);
-  virtual bool HasResult() const { return R != 0 && result() != NULL; }
+  virtual bool HasResult() const V8_FINAL V8_OVERRIDE {
+    return R != 0 && result() != NULL;
+  }
   void set_result(LOperand* operand) { results_[0] = operand; }
   LOperand* result() const { return results_[0]; }
 
@@ -324,15 +330,15 @@ class LTemplateInstruction: public LInstruction {
   EmbeddedContainer<LOperand*, T> temps_;
 
  private:
-  virtual int InputCount() { return I; }
-  virtual LOperand* InputAt(int i) { return inputs_[i]; }
+  virtual int InputCount() V8_FINAL V8_OVERRIDE { return I; }
+  virtual LOperand* InputAt(int i) V8_FINAL V8_OVERRIDE { return inputs_[i]; }
 
-  virtual int TempCount() { return T; }
-  virtual LOperand* TempAt(int i) { return temps_[i]; }
+  virtual int TempCount() V8_FINAL V8_OVERRIDE { return T; }
+  virtual LOperand* TempAt(int i) V8_FINAL V8_OVERRIDE { return temps_[i]; }
 };
 
 
-class LGap: public LTemplateInstruction<0, 0, 0> {
+class LGap : public LTemplateInstruction<0, 0, 0> {
  public:
   explicit LGap(HBasicBlock* block)
       : block_(block) {
@@ -343,8 +349,8 @@ class LGap: public LTemplateInstruction<0, 0, 0> {
   }
 
   // Can't use the DECLARE-macro here because of sub-classes.
-  virtual bool IsGap() const { return true; }
-  virtual void PrintDataTo(StringStream* stream);
+  virtual bool IsGap() const V8_FINAL V8_OVERRIDE { return true; }
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
   static LGap* cast(LInstruction* instr) {
     ASSERT(instr->IsGap());
     return reinterpret_cast<LGap*>(instr);
@@ -380,11 +386,11 @@ class LGap: public LTemplateInstruction<0, 0, 0> {
 };
 
 
-class LInstructionGap: public LGap {
+class LInstructionGap V8_FINAL : public LGap {
  public:
   explicit LInstructionGap(HBasicBlock* block) : LGap(block) { }
 
-  virtual bool HasInterestingComment(LCodeGen* gen) const {
+  virtual bool HasInterestingComment(LCodeGen* gen) const V8_OVERRIDE {
     return !IsRedundant();
   }
 
@@ -392,14 +398,14 @@ class LInstructionGap: public LGap {
 };
 
 
-class LGoto: public LTemplateInstruction<0, 0, 0> {
+class LGoto V8_FINAL : public LTemplateInstruction<0, 0, 0> {
  public:
   explicit LGoto(int block_id) : block_id_(block_id) { }
 
-  virtual bool HasInterestingComment(LCodeGen* gen) const;
+  virtual bool HasInterestingComment(LCodeGen* gen) const V8_OVERRIDE;
   DECLARE_CONCRETE_INSTRUCTION(Goto, "goto")
-  virtual void PrintDataTo(StringStream* stream);
-  virtual bool IsControl() const { return true; }
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
+  virtual bool IsControl() const V8_OVERRIDE { return true; }
 
   int block_id() const { return block_id_; }
 
@@ -408,7 +414,7 @@ class LGoto: public LTemplateInstruction<0, 0, 0> {
 };
 
 
-class LLazyBailout: public LTemplateInstruction<0, 0, 0> {
+class LLazyBailout V8_FINAL : public LTemplateInstruction<0, 0, 0> {
  public:
   LLazyBailout() : gap_instructions_size_(0) { }
 
@@ -424,7 +430,7 @@ class LLazyBailout: public LTemplateInstruction<0, 0, 0> {
 };
 
 
-class LDummyUse: public LTemplateInstruction<1, 1, 0> {
+class LDummyUse V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LDummyUse(LOperand* value) {
     inputs_[0] = value;
@@ -433,22 +439,24 @@ class LDummyUse: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LDeoptimize: public LTemplateInstruction<0, 0, 0> {
+class LDeoptimize V8_FINAL : public LTemplateInstruction<0, 0, 0> {
  public:
   DECLARE_CONCRETE_INSTRUCTION(Deoptimize, "deoptimize")
   DECLARE_HYDROGEN_ACCESSOR(Deoptimize)
 };
 
 
-class LLabel: public LGap {
+class LLabel V8_FINAL : public LGap {
  public:
   explicit LLabel(HBasicBlock* block)
       : LGap(block), replacement_(NULL) { }
 
-  virtual bool HasInterestingComment(LCodeGen* gen) const { return false; }
+  virtual bool HasInterestingComment(LCodeGen* gen) const V8_OVERRIDE {
+    return false;
+  }
   DECLARE_CONCRETE_INSTRUCTION(Label, "label")
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
   int block_id() const { return block()->block_id(); }
   bool is_loop_header() const { return block()->IsLoopHeader(); }
@@ -464,14 +472,16 @@ class LLabel: public LGap {
 };
 
 
-class LParameter: public LTemplateInstruction<1, 0, 0> {
+class LParameter V8_FINAL : public LTemplateInstruction<1, 0, 0> {
  public:
-  virtual bool HasInterestingComment(LCodeGen* gen) const { return false; }
+  virtual bool HasInterestingComment(LCodeGen* gen) const V8_OVERRIDE {
+    return false;
+  }
   DECLARE_CONCRETE_INSTRUCTION(Parameter, "parameter")
 };
 
 
-class LCallStub: public LTemplateInstruction<1, 0, 0> {
+class LCallStub V8_FINAL : public LTemplateInstruction<1, 0, 0> {
  public:
   DECLARE_CONCRETE_INSTRUCTION(CallStub, "call-stub")
   DECLARE_HYDROGEN_ACCESSOR(CallStub)
@@ -482,19 +492,21 @@ class LCallStub: public LTemplateInstruction<1, 0, 0> {
 };
 
 
-class LUnknownOSRValue: public LTemplateInstruction<1, 0, 0> {
+class LUnknownOSRValue V8_FINAL : public LTemplateInstruction<1, 0, 0> {
  public:
-  virtual bool HasInterestingComment(LCodeGen* gen) const { return false; }
+  virtual bool HasInterestingComment(LCodeGen* gen) const V8_OVERRIDE {
+    return false;
+  }
   DECLARE_CONCRETE_INSTRUCTION(UnknownOSRValue, "unknown-osr-value")
 };
 
 
 template<int I, int T>
-class LControlInstruction: public LTemplateInstruction<0, I, T> {
+class LControlInstruction : public LTemplateInstruction<0, I, T> {
  public:
   LControlInstruction() : false_label_(NULL), true_label_(NULL) { }
 
-  virtual bool IsControl() const { return true; }
+  virtual bool IsControl() const V8_FINAL V8_OVERRIDE { return true; }
 
   int SuccessorCount() { return hydrogen()->SuccessorCount(); }
   HBasicBlock* SuccessorAt(int i) { return hydrogen()->SuccessorAt(i); }
@@ -533,7 +545,7 @@ class LControlInstruction: public LTemplateInstruction<0, I, T> {
 };
 
 
-class LWrapReceiver: public LTemplateInstruction<1, 2, 0> {
+class LWrapReceiver V8_FINAL : public LTemplateInstruction<1, 2, 0> {
  public:
   LWrapReceiver(LOperand* receiver, LOperand* function) {
     inputs_[0] = receiver;
@@ -547,7 +559,7 @@ class LWrapReceiver: public LTemplateInstruction<1, 2, 0> {
 };
 
 
-class LApplyArguments: public LTemplateInstruction<1, 4, 0> {
+class LApplyArguments V8_FINAL : public LTemplateInstruction<1, 4, 0> {
  public:
   LApplyArguments(LOperand* function,
                   LOperand* receiver,
@@ -568,7 +580,7 @@ class LApplyArguments: public LTemplateInstruction<1, 4, 0> {
 };
 
 
-class LAccessArgumentsAt: public LTemplateInstruction<1, 3, 0> {
+class LAccessArgumentsAt V8_FINAL : public LTemplateInstruction<1, 3, 0> {
  public:
   LAccessArgumentsAt(LOperand* arguments, LOperand* length, LOperand* index) {
     inputs_[0] = arguments;
@@ -582,11 +594,11 @@ class LAccessArgumentsAt: public LTemplateInstruction<1, 3, 0> {
   LOperand* length() { return inputs_[1]; }
   LOperand* index() { return inputs_[2]; }
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 };
 
 
-class LArgumentsLength: public LTemplateInstruction<1, 1, 0> {
+class LArgumentsLength V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LArgumentsLength(LOperand* elements) {
     inputs_[0] = elements;
@@ -598,14 +610,14 @@ class LArgumentsLength: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LArgumentsElements: public LTemplateInstruction<1, 0, 0> {
+class LArgumentsElements V8_FINAL : public LTemplateInstruction<1, 0, 0> {
  public:
   DECLARE_CONCRETE_INSTRUCTION(ArgumentsElements, "arguments-elements")
   DECLARE_HYDROGEN_ACCESSOR(ArgumentsElements)
 };
 
 
-class LModI: public LTemplateInstruction<1, 2, 3> {
+class LModI V8_FINAL : public LTemplateInstruction<1, 2, 3> {
  public:
   // Used when the right hand is a constant power of 2.
   LModI(LOperand* left,
@@ -641,7 +653,7 @@ class LModI: public LTemplateInstruction<1, 2, 3> {
 };
 
 
-class LDivI: public LTemplateInstruction<1, 2, 0> {
+class LDivI V8_FINAL : public LTemplateInstruction<1, 2, 0> {
  public:
   LDivI(LOperand* left, LOperand* right) {
     inputs_[0] = left;
@@ -656,7 +668,7 @@ class LDivI: public LTemplateInstruction<1, 2, 0> {
 };
 
 
-class LMathFloorOfDiv: public LTemplateInstruction<1, 2, 1> {
+class LMathFloorOfDiv V8_FINAL : public LTemplateInstruction<1, 2, 1> {
  public:
   LMathFloorOfDiv(LOperand* left,
                   LOperand* right,
@@ -675,7 +687,7 @@ class LMathFloorOfDiv: public LTemplateInstruction<1, 2, 1> {
 };
 
 
-class LMulI: public LTemplateInstruction<1, 2, 1> {
+class LMulI V8_FINAL : public LTemplateInstruction<1, 2, 1> {
  public:
   LMulI(LOperand* left, LOperand* right, LOperand* temp) {
     inputs_[0] = left;
@@ -693,7 +705,7 @@ class LMulI: public LTemplateInstruction<1, 2, 1> {
 
 
 // Instruction for computing multiplier * multiplicand + addend.
-class LMultiplyAddD: public LTemplateInstruction<1, 3, 0> {
+class LMultiplyAddD V8_FINAL : public LTemplateInstruction<1, 3, 0> {
  public:
   LMultiplyAddD(LOperand* addend, LOperand* multiplier,
                 LOperand* multiplicand) {
@@ -710,13 +722,13 @@ class LMultiplyAddD: public LTemplateInstruction<1, 3, 0> {
 };
 
 
-class LDebugBreak: public LTemplateInstruction<0, 0, 0> {
+class LDebugBreak V8_FINAL : public LTemplateInstruction<0, 0, 0> {
  public:
   DECLARE_CONCRETE_INSTRUCTION(DebugBreak, "break")
 };
 
 
-class LCompareNumericAndBranch: public LControlInstruction<2, 0> {
+class LCompareNumericAndBranch V8_FINAL : public LControlInstruction<2, 0> {
  public:
   LCompareNumericAndBranch(LOperand* left, LOperand* right) {
     inputs_[0] = left;
@@ -735,11 +747,11 @@ class LCompareNumericAndBranch: public LControlInstruction<2, 0> {
     return hydrogen()->representation().IsDouble();
   }
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 };
 
 
-class LMathFloor: public LTemplateInstruction<1, 1, 1> {
+class LMathFloor V8_FINAL : public LTemplateInstruction<1, 1, 1> {
  public:
   LMathFloor(LOperand* value, LOperand* temp) {
     inputs_[0] = value;
@@ -754,7 +766,7 @@ class LMathFloor: public LTemplateInstruction<1, 1, 1> {
 };
 
 
-class LMathRound: public LTemplateInstruction<1, 1, 1> {
+class LMathRound V8_FINAL : public LTemplateInstruction<1, 1, 1> {
  public:
   LMathRound(LOperand* value, LOperand* temp) {
     inputs_[0] = value;
@@ -769,7 +781,7 @@ class LMathRound: public LTemplateInstruction<1, 1, 1> {
 };
 
 
-class LMathAbs: public LTemplateInstruction<1, 1, 0> {
+class LMathAbs V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LMathAbs(LOperand* value) {
     inputs_[0] = value;
@@ -782,7 +794,7 @@ class LMathAbs: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LMathLog: public LTemplateInstruction<1, 1, 0> {
+class LMathLog V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LMathLog(LOperand* value) {
     inputs_[0] = value;
@@ -794,7 +806,7 @@ class LMathLog: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LMathSin: public LTemplateInstruction<1, 1, 0> {
+class LMathSin V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LMathSin(LOperand* value) {
     inputs_[0] = value;
@@ -806,7 +818,7 @@ class LMathSin: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LMathCos: public LTemplateInstruction<1, 1, 0> {
+class LMathCos V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LMathCos(LOperand* value) {
     inputs_[0] = value;
@@ -818,7 +830,7 @@ class LMathCos: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LMathTan: public LTemplateInstruction<1, 1, 0> {
+class LMathTan V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LMathTan(LOperand* value) {
     inputs_[0] = value;
@@ -830,7 +842,7 @@ class LMathTan: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LMathExp: public LTemplateInstruction<1, 1, 3> {
+class LMathExp V8_FINAL : public LTemplateInstruction<1, 1, 3> {
  public:
   LMathExp(LOperand* value,
            LOperand* double_temp,
@@ -852,7 +864,7 @@ class LMathExp: public LTemplateInstruction<1, 1, 3> {
 };
 
 
-class LMathSqrt: public LTemplateInstruction<1, 1, 0> {
+class LMathSqrt V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LMathSqrt(LOperand* value) {
     inputs_[0] = value;
@@ -864,7 +876,7 @@ class LMathSqrt: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LMathPowHalf: public LTemplateInstruction<1, 1, 1> {
+class LMathPowHalf V8_FINAL : public LTemplateInstruction<1, 1, 1> {
  public:
   LMathPowHalf(LOperand* value, LOperand* temp) {
     inputs_[0] = value;
@@ -878,7 +890,7 @@ class LMathPowHalf: public LTemplateInstruction<1, 1, 1> {
 };
 
 
-class LCmpObjectEqAndBranch: public LControlInstruction<2, 0> {
+class LCmpObjectEqAndBranch V8_FINAL : public LControlInstruction<2, 0> {
  public:
   LCmpObjectEqAndBranch(LOperand* left, LOperand* right) {
     inputs_[0] = left;
@@ -893,7 +905,7 @@ class LCmpObjectEqAndBranch: public LControlInstruction<2, 0> {
 };
 
 
-class LCmpHoleAndBranch: public LControlInstruction<1, 0> {
+class LCmpHoleAndBranch V8_FINAL : public LControlInstruction<1, 0> {
  public:
   explicit LCmpHoleAndBranch(LOperand* object) {
     inputs_[0] = object;
@@ -906,7 +918,7 @@ class LCmpHoleAndBranch: public LControlInstruction<1, 0> {
 };
 
 
-class LIsObjectAndBranch: public LControlInstruction<1, 1> {
+class LIsObjectAndBranch V8_FINAL : public LControlInstruction<1, 1> {
  public:
   LIsObjectAndBranch(LOperand* value, LOperand* temp) {
     inputs_[0] = value;
@@ -923,7 +935,7 @@ class LIsObjectAndBranch: public LControlInstruction<1, 1> {
 };
 
 
-class LIsNumberAndBranch: public LControlInstruction<1, 0> {
+class LIsNumberAndBranch V8_FINAL : public LControlInstruction<1, 0> {
  public:
   explicit LIsNumberAndBranch(LOperand* value) {
     inputs_[0] = value;
@@ -936,7 +948,7 @@ class LIsNumberAndBranch: public LControlInstruction<1, 0> {
 };
 
 
-class LIsStringAndBranch: public LControlInstruction<1, 1> {
+class LIsStringAndBranch V8_FINAL : public LControlInstruction<1, 1> {
  public:
   LIsStringAndBranch(LOperand* value, LOperand* temp) {
     inputs_[0] = value;
@@ -949,11 +961,11 @@ class LIsStringAndBranch: public LControlInstruction<1, 1> {
   DECLARE_CONCRETE_INSTRUCTION(IsStringAndBranch, "is-string-and-branch")
   DECLARE_HYDROGEN_ACCESSOR(IsStringAndBranch)
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 };
 
 
-class LIsSmiAndBranch: public LControlInstruction<1, 0> {
+class LIsSmiAndBranch V8_FINAL : public LControlInstruction<1, 0> {
  public:
   explicit LIsSmiAndBranch(LOperand* value) {
     inputs_[0] = value;
@@ -964,11 +976,11 @@ class LIsSmiAndBranch: public LControlInstruction<1, 0> {
   DECLARE_CONCRETE_INSTRUCTION(IsSmiAndBranch, "is-smi-and-branch")
   DECLARE_HYDROGEN_ACCESSOR(IsSmiAndBranch)
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 };
 
 
-class LIsUndetectableAndBranch: public LControlInstruction<1, 1> {
+class LIsUndetectableAndBranch V8_FINAL : public LControlInstruction<1, 1> {
  public:
   explicit LIsUndetectableAndBranch(LOperand* value, LOperand* temp) {
     inputs_[0] = value;
@@ -982,11 +994,11 @@ class LIsUndetectableAndBranch: public LControlInstruction<1, 1> {
                                "is-undetectable-and-branch")
   DECLARE_HYDROGEN_ACCESSOR(IsUndetectableAndBranch)
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 };
 
 
-class LStringCompareAndBranch: public LControlInstruction<2, 0> {
+class LStringCompareAndBranch V8_FINAL : public LControlInstruction<2, 0> {
  public:
   LStringCompareAndBranch(LOperand* left, LOperand* right) {
     inputs_[0] = left;
@@ -1002,11 +1014,11 @@ class LStringCompareAndBranch: public LControlInstruction<2, 0> {
 
   Token::Value op() const { return hydrogen()->token(); }
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 };
 
 
-class LHasInstanceTypeAndBranch: public LControlInstruction<1, 0> {
+class LHasInstanceTypeAndBranch V8_FINAL : public LControlInstruction<1, 0> {
  public:
   explicit LHasInstanceTypeAndBranch(LOperand* value) {
     inputs_[0] = value;
@@ -1018,11 +1030,11 @@ class LHasInstanceTypeAndBranch: public LControlInstruction<1, 0> {
                                "has-instance-type-and-branch")
   DECLARE_HYDROGEN_ACCESSOR(HasInstanceTypeAndBranch)
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 };
 
 
-class LGetCachedArrayIndex: public LTemplateInstruction<1, 1, 0> {
+class LGetCachedArrayIndex V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LGetCachedArrayIndex(LOperand* value) {
     inputs_[0] = value;
@@ -1035,7 +1047,8 @@ class LGetCachedArrayIndex: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LHasCachedArrayIndexAndBranch: public LControlInstruction<1, 0> {
+class LHasCachedArrayIndexAndBranch V8_FINAL
+    : public LControlInstruction<1, 0> {
  public:
   explicit LHasCachedArrayIndexAndBranch(LOperand* value) {
     inputs_[0] = value;
@@ -1047,11 +1060,11 @@ class LHasCachedArrayIndexAndBranch: public LControlInstruction<1, 0> {
                                "has-cached-array-index-and-branch")
   DECLARE_HYDROGEN_ACCESSOR(HasCachedArrayIndexAndBranch)
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 };
 
 
-class LClassOfTestAndBranch: public LControlInstruction<1, 1> {
+class LClassOfTestAndBranch V8_FINAL : public LControlInstruction<1, 1> {
  public:
   LClassOfTestAndBranch(LOperand* value, LOperand* temp) {
     inputs_[0] = value;
@@ -1065,11 +1078,11 @@ class LClassOfTestAndBranch: public LControlInstruction<1, 1> {
                                "class-of-test-and-branch")
   DECLARE_HYDROGEN_ACCESSOR(ClassOfTestAndBranch)
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 };
 
 
-class LCmpT: public LTemplateInstruction<1, 2, 0> {
+class LCmpT V8_FINAL : public LTemplateInstruction<1, 2, 0> {
  public:
   LCmpT(LOperand* left, LOperand* right) {
     inputs_[0] = left;
@@ -1086,7 +1099,7 @@ class LCmpT: public LTemplateInstruction<1, 2, 0> {
 };
 
 
-class LInstanceOf: public LTemplateInstruction<1, 2, 0> {
+class LInstanceOf V8_FINAL : public LTemplateInstruction<1, 2, 0> {
  public:
   LInstanceOf(LOperand* left, LOperand* right) {
     inputs_[0] = left;
@@ -1100,7 +1113,7 @@ class LInstanceOf: public LTemplateInstruction<1, 2, 0> {
 };
 
 
-class LInstanceOfKnownGlobal: public LTemplateInstruction<1, 1, 1> {
+class LInstanceOfKnownGlobal V8_FINAL : public LTemplateInstruction<1, 1, 1> {
  public:
   LInstanceOfKnownGlobal(LOperand* value, LOperand* temp) {
     inputs_[0] = value;
@@ -1118,7 +1131,8 @@ class LInstanceOfKnownGlobal: public LTemplateInstruction<1, 1, 1> {
   LEnvironment* GetDeferredLazyDeoptimizationEnvironment() {
     return lazy_deopt_env_;
   }
-  virtual void SetDeferredLazyDeoptimizationEnvironment(LEnvironment* env) {
+  virtual void SetDeferredLazyDeoptimizationEnvironment(
+      LEnvironment* env) V8_OVERRIDE {
     lazy_deopt_env_ = env;
   }
 
@@ -1127,7 +1141,7 @@ class LInstanceOfKnownGlobal: public LTemplateInstruction<1, 1, 1> {
 };
 
 
-class LInstanceSize: public LTemplateInstruction<1, 1, 0> {
+class LInstanceSize V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LInstanceSize(LOperand* object) {
     inputs_[0] = object;
@@ -1140,7 +1154,7 @@ class LInstanceSize: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LBoundsCheck: public LTemplateInstruction<0, 2, 0> {
+class LBoundsCheck V8_FINAL : public LTemplateInstruction<0, 2, 0> {
  public:
   LBoundsCheck(LOperand* index, LOperand* length) {
     inputs_[0] = index;
@@ -1155,7 +1169,7 @@ class LBoundsCheck: public LTemplateInstruction<0, 2, 0> {
 };
 
 
-class LBitI: public LTemplateInstruction<1, 2, 0> {
+class LBitI V8_FINAL : public LTemplateInstruction<1, 2, 0> {
  public:
   LBitI(LOperand* left, LOperand* right) {
     inputs_[0] = left;
@@ -1172,7 +1186,7 @@ class LBitI: public LTemplateInstruction<1, 2, 0> {
 };
 
 
-class LShiftI: public LTemplateInstruction<1, 2, 0> {
+class LShiftI V8_FINAL : public LTemplateInstruction<1, 2, 0> {
  public:
   LShiftI(Token::Value op, LOperand* left, LOperand* right, bool can_deopt)
       : op_(op), can_deopt_(can_deopt) {
@@ -1193,7 +1207,7 @@ class LShiftI: public LTemplateInstruction<1, 2, 0> {
 };
 
 
-class LSubI: public LTemplateInstruction<1, 2, 0> {
+class LSubI V8_FINAL : public LTemplateInstruction<1, 2, 0> {
  public:
   LSubI(LOperand* left, LOperand* right) {
     inputs_[0] = left;
@@ -1208,7 +1222,7 @@ class LSubI: public LTemplateInstruction<1, 2, 0> {
 };
 
 
-class LConstantI: public LTemplateInstruction<1, 0, 0> {
+class LConstantI V8_FINAL : public LTemplateInstruction<1, 0, 0> {
  public:
   DECLARE_CONCRETE_INSTRUCTION(ConstantI, "constant-i")
   DECLARE_HYDROGEN_ACCESSOR(Constant)
@@ -1217,7 +1231,7 @@ class LConstantI: public LTemplateInstruction<1, 0, 0> {
 };
 
 
-class LConstantS: public LTemplateInstruction<1, 0, 0> {
+class LConstantS V8_FINAL : public LTemplateInstruction<1, 0, 0> {
  public:
   DECLARE_CONCRETE_INSTRUCTION(ConstantS, "constant-s")
   DECLARE_HYDROGEN_ACCESSOR(Constant)
@@ -1226,7 +1240,7 @@ class LConstantS: public LTemplateInstruction<1, 0, 0> {
 };
 
 
-class LConstantD: public LTemplateInstruction<1, 0, 0> {
+class LConstantD V8_FINAL : public LTemplateInstruction<1, 0, 0> {
  public:
   DECLARE_CONCRETE_INSTRUCTION(ConstantD, "constant-d")
   DECLARE_HYDROGEN_ACCESSOR(Constant)
@@ -1235,7 +1249,7 @@ class LConstantD: public LTemplateInstruction<1, 0, 0> {
 };
 
 
-class LConstantE: public LTemplateInstruction<1, 0, 0> {
+class LConstantE V8_FINAL : public LTemplateInstruction<1, 0, 0> {
  public:
   DECLARE_CONCRETE_INSTRUCTION(ConstantE, "constant-e")
   DECLARE_HYDROGEN_ACCESSOR(Constant)
@@ -1246,7 +1260,7 @@ class LConstantE: public LTemplateInstruction<1, 0, 0> {
 };
 
 
-class LConstantT: public LTemplateInstruction<1, 0, 0> {
+class LConstantT V8_FINAL : public LTemplateInstruction<1, 0, 0> {
  public:
   DECLARE_CONCRETE_INSTRUCTION(ConstantT, "constant-t")
   DECLARE_HYDROGEN_ACCESSOR(Constant)
@@ -1255,7 +1269,7 @@ class LConstantT: public LTemplateInstruction<1, 0, 0> {
 };
 
 
-class LBranch: public LControlInstruction<1, 0> {
+class LBranch V8_FINAL : public LControlInstruction<1, 0> {
  public:
   explicit LBranch(LOperand* value) {
     inputs_[0] = value;
@@ -1266,11 +1280,11 @@ class LBranch: public LControlInstruction<1, 0> {
   DECLARE_CONCRETE_INSTRUCTION(Branch, "branch")
   DECLARE_HYDROGEN_ACCESSOR(Branch)
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 };
 
 
-class LCmpMapAndBranch: public LControlInstruction<1, 1> {
+class LCmpMapAndBranch V8_FINAL : public LControlInstruction<1, 1> {
  public:
   LCmpMapAndBranch(LOperand* value, LOperand* temp) {
     inputs_[0] = value;
@@ -1287,7 +1301,7 @@ class LCmpMapAndBranch: public LControlInstruction<1, 1> {
 };
 
 
-class LMapEnumLength: public LTemplateInstruction<1, 1, 0> {
+class LMapEnumLength V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LMapEnumLength(LOperand* value) {
     inputs_[0] = value;
@@ -1299,7 +1313,7 @@ class LMapEnumLength: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LElementsKind: public LTemplateInstruction<1, 1, 0> {
+class LElementsKind V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LElementsKind(LOperand* value) {
     inputs_[0] = value;
@@ -1312,7 +1326,7 @@ class LElementsKind: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LValueOf: public LTemplateInstruction<1, 1, 1> {
+class LValueOf V8_FINAL : public LTemplateInstruction<1, 1, 1> {
  public:
   LValueOf(LOperand* value, LOperand* temp) {
     inputs_[0] = value;
@@ -1327,7 +1341,7 @@ class LValueOf: public LTemplateInstruction<1, 1, 1> {
 };
 
 
-class LDateField: public LTemplateInstruction<1, 1, 1> {
+class LDateField V8_FINAL : public LTemplateInstruction<1, 1, 1> {
  public:
   LDateField(LOperand* date, LOperand* temp, Smi* index) : index_(index) {
     inputs_[0] = date;
@@ -1346,7 +1360,7 @@ class LDateField: public LTemplateInstruction<1, 1, 1> {
 };
 
 
-class LSeqStringSetChar: public LTemplateInstruction<1, 3, 0> {
+class LSeqStringSetChar V8_FINAL : public LTemplateInstruction<1, 3, 0> {
  public:
   LSeqStringSetChar(String::Encoding encoding,
                     LOperand* string,
@@ -1370,7 +1384,7 @@ class LSeqStringSetChar: public LTemplateInstruction<1, 3, 0> {
 };
 
 
-class LThrow: public LTemplateInstruction<0, 1, 0> {
+class LThrow V8_FINAL : public LTemplateInstruction<0, 1, 0> {
  public:
   explicit LThrow(LOperand* value) {
     inputs_[0] = value;
@@ -1382,7 +1396,7 @@ class LThrow: public LTemplateInstruction<0, 1, 0> {
 };
 
 
-class LAddI: public LTemplateInstruction<1, 2, 0> {
+class LAddI V8_FINAL : public LTemplateInstruction<1, 2, 0> {
  public:
   LAddI(LOperand* left, LOperand* right) {
     inputs_[0] = left;
@@ -1397,7 +1411,7 @@ class LAddI: public LTemplateInstruction<1, 2, 0> {
 };
 
 
-class LMathMinMax: public LTemplateInstruction<1, 2, 0> {
+class LMathMinMax V8_FINAL : public LTemplateInstruction<1, 2, 0> {
  public:
   LMathMinMax(LOperand* left, LOperand* right) {
     inputs_[0] = left;
@@ -1412,7 +1426,7 @@ class LMathMinMax: public LTemplateInstruction<1, 2, 0> {
 };
 
 
-class LPower: public LTemplateInstruction<1, 2, 0> {
+class LPower V8_FINAL : public LTemplateInstruction<1, 2, 0> {
  public:
   LPower(LOperand* left, LOperand* right) {
     inputs_[0] = left;
@@ -1427,7 +1441,7 @@ class LPower: public LTemplateInstruction<1, 2, 0> {
 };
 
 
-class LRandom: public LTemplateInstruction<1, 1, 0> {
+class LRandom V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LRandom(LOperand* global_object) {
     inputs_[0] = global_object;
@@ -1440,7 +1454,7 @@ class LRandom: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LArithmeticD: public LTemplateInstruction<1, 2, 0> {
+class LArithmeticD V8_FINAL : public LTemplateInstruction<1, 2, 0> {
  public:
   LArithmeticD(Token::Value op, LOperand* left, LOperand* right)
       : op_(op) {
@@ -1452,16 +1466,18 @@ class LArithmeticD: public LTemplateInstruction<1, 2, 0> {
   LOperand* left() { return inputs_[0]; }
   LOperand* right() { return inputs_[1]; }
 
-  virtual Opcode opcode() const { return LInstruction::kArithmeticD; }
-  virtual void CompileToNative(LCodeGen* generator);
-  virtual const char* Mnemonic() const;
+  virtual Opcode opcode() const V8_OVERRIDE {
+    return LInstruction::kArithmeticD;
+  }
+  virtual void CompileToNative(LCodeGen* generator) V8_OVERRIDE;
+  virtual const char* Mnemonic() const V8_OVERRIDE;
 
  private:
   Token::Value op_;
 };
 
 
-class LArithmeticT: public LTemplateInstruction<1, 2, 0> {
+class LArithmeticT V8_FINAL : public LTemplateInstruction<1, 2, 0> {
  public:
   LArithmeticT(Token::Value op, LOperand* left, LOperand* right)
       : op_(op) {
@@ -1473,16 +1489,16 @@ class LArithmeticT: public LTemplateInstruction<1, 2, 0> {
   LOperand* right() { return inputs_[1]; }
   Token::Value op() const { return op_; }
 
-  virtual Opcode opcode() const { return LInstruction::kArithmeticT; }
-  virtual void CompileToNative(LCodeGen* generator);
-  virtual const char* Mnemonic() const;
+  virtual Opcode opcode() const V8_FINAL  { return LInstruction::kArithmeticT; }
+  virtual void CompileToNative(LCodeGen* generator) V8_OVERRIDE;
+  virtual const char* Mnemonic() const V8_OVERRIDE;
 
  private:
   Token::Value op_;
 };
 
 
-class LReturn: public LTemplateInstruction<0, 2, 0> {
+class LReturn V8_FINAL : public LTemplateInstruction<0, 2, 0> {
  public:
   explicit LReturn(LOperand* value, LOperand* parameter_count) {
     inputs_[0] = value;
@@ -1504,7 +1520,7 @@ class LReturn: public LTemplateInstruction<0, 2, 0> {
 };
 
 
-class LLoadNamedField: public LTemplateInstruction<1, 1, 0> {
+class LLoadNamedField V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LLoadNamedField(LOperand* object) {
     inputs_[0] = object;
@@ -1517,7 +1533,7 @@ class LLoadNamedField: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LLoadNamedGeneric: public LTemplateInstruction<1, 1, 0> {
+class LLoadNamedGeneric V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LLoadNamedGeneric(LOperand* object) {
     inputs_[0] = object;
@@ -1532,7 +1548,7 @@ class LLoadNamedGeneric: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LLoadFunctionPrototype: public LTemplateInstruction<1, 1, 0> {
+class LLoadFunctionPrototype V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LLoadFunctionPrototype(LOperand* function) {
     inputs_[0] = function;
@@ -1545,7 +1561,8 @@ class LLoadFunctionPrototype: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LLoadExternalArrayPointer: public LTemplateInstruction<1, 1, 0> {
+class LLoadExternalArrayPointer V8_FINAL
+    : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LLoadExternalArrayPointer(LOperand* object) {
     inputs_[0] = object;
@@ -1558,7 +1575,7 @@ class LLoadExternalArrayPointer: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LLoadKeyed: public LTemplateInstruction<1, 2, 0> {
+class LLoadKeyed V8_FINAL : public LTemplateInstruction<1, 2, 0> {
  public:
   LLoadKeyed(LOperand* elements, LOperand* key) {
     inputs_[0] = elements;
@@ -1582,7 +1599,7 @@ class LLoadKeyed: public LTemplateInstruction<1, 2, 0> {
 };
 
 
-class LLoadKeyedGeneric: public LTemplateInstruction<1, 2, 0> {
+class LLoadKeyedGeneric V8_FINAL : public LTemplateInstruction<1, 2, 0> {
  public:
   LLoadKeyedGeneric(LOperand* object, LOperand* key) {
     inputs_[0] = object;
@@ -1596,14 +1613,14 @@ class LLoadKeyedGeneric: public LTemplateInstruction<1, 2, 0> {
 };
 
 
-class LLoadGlobalCell: public LTemplateInstruction<1, 0, 0> {
+class LLoadGlobalCell V8_FINAL : public LTemplateInstruction<1, 0, 0> {
  public:
   DECLARE_CONCRETE_INSTRUCTION(LoadGlobalCell, "load-global-cell")
   DECLARE_HYDROGEN_ACCESSOR(LoadGlobalCell)
 };
 
 
-class LLoadGlobalGeneric: public LTemplateInstruction<1, 1, 0> {
+class LLoadGlobalGeneric V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LLoadGlobalGeneric(LOperand* global_object) {
     inputs_[0] = global_object;
@@ -1619,7 +1636,7 @@ class LLoadGlobalGeneric: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LStoreGlobalCell: public LTemplateInstruction<0, 1, 1> {
+class LStoreGlobalCell V8_FINAL : public LTemplateInstruction<0, 1, 1> {
  public:
   LStoreGlobalCell(LOperand* value, LOperand* temp) {
     inputs_[0] = value;
@@ -1634,7 +1651,7 @@ class LStoreGlobalCell: public LTemplateInstruction<0, 1, 1> {
 };
 
 
-class LStoreGlobalGeneric: public LTemplateInstruction<0, 2, 0> {
+class LStoreGlobalGeneric V8_FINAL : public LTemplateInstruction<0, 2, 0> {
  public:
   explicit LStoreGlobalGeneric(LOperand* global_object,
                                LOperand* value) {
@@ -1653,7 +1670,7 @@ class LStoreGlobalGeneric: public LTemplateInstruction<0, 2, 0> {
 };
 
 
-class LLoadContextSlot: public LTemplateInstruction<1, 1, 0> {
+class LLoadContextSlot V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LLoadContextSlot(LOperand* context) {
     inputs_[0] = context;
@@ -1670,7 +1687,7 @@ class LLoadContextSlot: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LStoreContextSlot: public LTemplateInstruction<0, 2, 0> {
+class LStoreContextSlot V8_FINAL : public LTemplateInstruction<0, 2, 0> {
  public:
   LStoreContextSlot(LOperand* context, LOperand* value) {
     inputs_[0] = context;
@@ -1685,11 +1702,11 @@ class LStoreContextSlot: public LTemplateInstruction<0, 2, 0> {
 
   int slot_index() { return hydrogen()->slot_index(); }
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 };
 
 
-class LPushArgument: public LTemplateInstruction<0, 1, 0> {
+class LPushArgument V8_FINAL : public LTemplateInstruction<0, 1, 0> {
  public:
   explicit LPushArgument(LOperand* value) {
     inputs_[0] = value;
@@ -1701,7 +1718,7 @@ class LPushArgument: public LTemplateInstruction<0, 1, 0> {
 };
 
 
-class LDrop: public LTemplateInstruction<0, 0, 0> {
+class LDrop V8_FINAL : public LTemplateInstruction<0, 0, 0> {
  public:
   explicit LDrop(int count) : count_(count) { }
 
@@ -1714,7 +1731,7 @@ class LDrop: public LTemplateInstruction<0, 0, 0> {
 };
 
 
-class LInnerAllocatedObject: public LTemplateInstruction<1, 1, 0> {
+class LInnerAllocatedObject V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LInnerAllocatedObject(LOperand* base_object) {
     inputs_[0] = base_object;
@@ -1723,28 +1740,28 @@ class LInnerAllocatedObject: public LTemplateInstruction<1, 1, 0> {
   LOperand* base_object() { return inputs_[0]; }
   int offset() { return hydrogen()->offset(); }
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
   DECLARE_CONCRETE_INSTRUCTION(InnerAllocatedObject, "sub-allocated-object")
   DECLARE_HYDROGEN_ACCESSOR(InnerAllocatedObject)
 };
 
 
-class LThisFunction: public LTemplateInstruction<1, 0, 0> {
+class LThisFunction V8_FINAL : public LTemplateInstruction<1, 0, 0> {
  public:
   DECLARE_CONCRETE_INSTRUCTION(ThisFunction, "this-function")
   DECLARE_HYDROGEN_ACCESSOR(ThisFunction)
 };
 
 
-class LContext: public LTemplateInstruction<1, 0, 0> {
+class LContext V8_FINAL : public LTemplateInstruction<1, 0, 0> {
  public:
   DECLARE_CONCRETE_INSTRUCTION(Context, "context")
   DECLARE_HYDROGEN_ACCESSOR(Context)
 };
 
 
-class LOuterContext: public LTemplateInstruction<1, 1, 0> {
+class LOuterContext V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LOuterContext(LOperand* context) {
     inputs_[0] = context;
@@ -1756,14 +1773,14 @@ class LOuterContext: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LDeclareGlobals: public LTemplateInstruction<0, 0, 0> {
+class LDeclareGlobals V8_FINAL : public LTemplateInstruction<0, 0, 0> {
  public:
   DECLARE_CONCRETE_INSTRUCTION(DeclareGlobals, "declare-globals")
   DECLARE_HYDROGEN_ACCESSOR(DeclareGlobals)
 };
 
 
-class LGlobalObject: public LTemplateInstruction<1, 1, 0> {
+class LGlobalObject V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LGlobalObject(LOperand* context) {
     inputs_[0] = context;
@@ -1775,7 +1792,7 @@ class LGlobalObject: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LGlobalReceiver: public LTemplateInstruction<1, 1, 0> {
+class LGlobalReceiver V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LGlobalReceiver(LOperand* global_object) {
     inputs_[0] = global_object;
@@ -1787,19 +1804,19 @@ class LGlobalReceiver: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LCallConstantFunction: public LTemplateInstruction<1, 0, 0> {
+class LCallConstantFunction V8_FINAL : public LTemplateInstruction<1, 0, 0> {
  public:
   DECLARE_CONCRETE_INSTRUCTION(CallConstantFunction, "call-constant-function")
   DECLARE_HYDROGEN_ACCESSOR(CallConstantFunction)
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
   Handle<JSFunction> function() { return hydrogen()->function(); }
   int arity() const { return hydrogen()->argument_count() - 1; }
 };
 
 
-class LInvokeFunction: public LTemplateInstruction<1, 1, 0> {
+class LInvokeFunction V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LInvokeFunction(LOperand* function) {
     inputs_[0] = function;
@@ -1810,13 +1827,13 @@ class LInvokeFunction: public LTemplateInstruction<1, 1, 0> {
   DECLARE_CONCRETE_INSTRUCTION(InvokeFunction, "invoke-function")
   DECLARE_HYDROGEN_ACCESSOR(InvokeFunction)
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
   int arity() const { return hydrogen()->argument_count() - 1; }
 };
 
 
-class LCallKeyed: public LTemplateInstruction<1, 1, 0> {
+class LCallKeyed V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LCallKeyed(LOperand* key) {
     inputs_[0] = key;
@@ -1827,26 +1844,26 @@ class LCallKeyed: public LTemplateInstruction<1, 1, 0> {
   DECLARE_CONCRETE_INSTRUCTION(CallKeyed, "call-keyed")
   DECLARE_HYDROGEN_ACCESSOR(CallKeyed)
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
   int arity() const { return hydrogen()->argument_count() - 1; }
 };
 
 
 
-class LCallNamed: public LTemplateInstruction<1, 0, 0> {
+class LCallNamed V8_FINAL : public LTemplateInstruction<1, 0, 0> {
  public:
   DECLARE_CONCRETE_INSTRUCTION(CallNamed, "call-named")
   DECLARE_HYDROGEN_ACCESSOR(CallNamed)
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
   Handle<String> name() const { return hydrogen()->name(); }
   int arity() const { return hydrogen()->argument_count() - 1; }
 };
 
 
-class LCallFunction: public LTemplateInstruction<1, 1, 0> {
+class LCallFunction V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LCallFunction(LOperand* function) {
     inputs_[0] = function;
@@ -1861,7 +1878,7 @@ class LCallFunction: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LCallGlobal: public LTemplateInstruction<1, 0, 0> {
+class LCallGlobal V8_FINAL : public LTemplateInstruction<1, 0, 0> {
  public:
   DECLARE_CONCRETE_INSTRUCTION(CallGlobal, "call-global")
   DECLARE_HYDROGEN_ACCESSOR(CallGlobal)
@@ -1873,18 +1890,18 @@ class LCallGlobal: public LTemplateInstruction<1, 0, 0> {
 };
 
 
-class LCallKnownGlobal: public LTemplateInstruction<1, 0, 0> {
+class LCallKnownGlobal V8_FINAL : public LTemplateInstruction<1, 0, 0> {
  public:
   DECLARE_CONCRETE_INSTRUCTION(CallKnownGlobal, "call-known-global")
   DECLARE_HYDROGEN_ACCESSOR(CallKnownGlobal)
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
   int arity() const { return hydrogen()->argument_count() - 1;  }
 };
 
 
-class LCallNew: public LTemplateInstruction<1, 1, 0> {
+class LCallNew V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LCallNew(LOperand* constructor) {
     inputs_[0] = constructor;
@@ -1895,13 +1912,13 @@ class LCallNew: public LTemplateInstruction<1, 1, 0> {
   DECLARE_CONCRETE_INSTRUCTION(CallNew, "call-new")
   DECLARE_HYDROGEN_ACCESSOR(CallNew)
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
   int arity() const { return hydrogen()->argument_count() - 1; }
 };
 
 
-class LCallNewArray: public LTemplateInstruction<1, 1, 0> {
+class LCallNewArray V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LCallNewArray(LOperand* constructor) {
     inputs_[0] = constructor;
@@ -1912,13 +1929,13 @@ class LCallNewArray: public LTemplateInstruction<1, 1, 0> {
   DECLARE_CONCRETE_INSTRUCTION(CallNewArray, "call-new-array")
   DECLARE_HYDROGEN_ACCESSOR(CallNewArray)
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
   int arity() const { return hydrogen()->argument_count() - 1; }
 };
 
 
-class LCallRuntime: public LTemplateInstruction<1, 0, 0> {
+class LCallRuntime V8_FINAL : public LTemplateInstruction<1, 0, 0> {
  public:
   DECLARE_CONCRETE_INSTRUCTION(CallRuntime, "call-runtime")
   DECLARE_HYDROGEN_ACCESSOR(CallRuntime)
@@ -1928,7 +1945,7 @@ class LCallRuntime: public LTemplateInstruction<1, 0, 0> {
 };
 
 
-class LInteger32ToDouble: public LTemplateInstruction<1, 1, 0> {
+class LInteger32ToDouble V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LInteger32ToDouble(LOperand* value) {
     inputs_[0] = value;
@@ -1940,7 +1957,7 @@ class LInteger32ToDouble: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LInteger32ToSmi: public LTemplateInstruction<1, 1, 0> {
+class LInteger32ToSmi V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LInteger32ToSmi(LOperand* value) {
     inputs_[0] = value;
@@ -1953,7 +1970,7 @@ class LInteger32ToSmi: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LUint32ToDouble: public LTemplateInstruction<1, 1, 0> {
+class LUint32ToDouble V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LUint32ToDouble(LOperand* value) {
     inputs_[0] = value;
@@ -1965,7 +1982,7 @@ class LUint32ToDouble: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LNumberTagI: public LTemplateInstruction<1, 1, 0> {
+class LNumberTagI V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LNumberTagI(LOperand* value) {
     inputs_[0] = value;
@@ -1977,7 +1994,7 @@ class LNumberTagI: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LNumberTagU: public LTemplateInstruction<1, 1, 0> {
+class LNumberTagU V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LNumberTagU(LOperand* value) {
     inputs_[0] = value;
@@ -1989,7 +2006,7 @@ class LNumberTagU: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LNumberTagD: public LTemplateInstruction<1, 1, 2> {
+class LNumberTagD V8_FINAL : public LTemplateInstruction<1, 1, 2> {
  public:
   LNumberTagD(LOperand* value, LOperand* temp, LOperand* temp2) {
     inputs_[0] = value;
@@ -2006,7 +2023,7 @@ class LNumberTagD: public LTemplateInstruction<1, 1, 2> {
 };
 
 
-class LDoubleToSmi: public LTemplateInstruction<1, 1, 2> {
+class LDoubleToSmi V8_FINAL : public LTemplateInstruction<1, 1, 2> {
  public:
   LDoubleToSmi(LOperand* value, LOperand* temp, LOperand* temp2) {
     inputs_[0] = value;
@@ -2026,7 +2043,7 @@ class LDoubleToSmi: public LTemplateInstruction<1, 1, 2> {
 
 
 // Sometimes truncating conversion from a tagged value to an int32.
-class LDoubleToI: public LTemplateInstruction<1, 1, 2> {
+class LDoubleToI V8_FINAL : public LTemplateInstruction<1, 1, 2> {
  public:
   LDoubleToI(LOperand* value, LOperand* temp, LOperand* temp2) {
     inputs_[0] = value;
@@ -2046,7 +2063,7 @@ class LDoubleToI: public LTemplateInstruction<1, 1, 2> {
 
 
 // Truncating conversion from a tagged value to an int32.
-class LTaggedToI: public LTemplateInstruction<1, 1, 3> {
+class LTaggedToI V8_FINAL : public LTemplateInstruction<1, 1, 3> {
  public:
   LTaggedToI(LOperand* value,
              LOperand* temp,
@@ -2070,7 +2087,7 @@ class LTaggedToI: public LTemplateInstruction<1, 1, 3> {
 };
 
 
-class LSmiTag: public LTemplateInstruction<1, 1, 0> {
+class LSmiTag V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LSmiTag(LOperand* value) {
     inputs_[0] = value;
@@ -2082,7 +2099,7 @@ class LSmiTag: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LNumberUntagD: public LTemplateInstruction<1, 1, 0> {
+class LNumberUntagD V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LNumberUntagD(LOperand* value) {
     inputs_[0] = value;
@@ -2095,7 +2112,7 @@ class LNumberUntagD: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LSmiUntag: public LTemplateInstruction<1, 1, 0> {
+class LSmiUntag V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   LSmiUntag(LOperand* value, bool needs_check)
       : needs_check_(needs_check) {
@@ -2112,7 +2129,7 @@ class LSmiUntag: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LStoreNamedField: public LTemplateInstruction<0, 2, 1> {
+class LStoreNamedField V8_FINAL : public LTemplateInstruction<0, 2, 1> {
  public:
   LStoreNamedField(LOperand* object, LOperand* value, LOperand* temp) {
     inputs_[0] = object;
@@ -2127,7 +2144,7 @@ class LStoreNamedField: public LTemplateInstruction<0, 2, 1> {
   DECLARE_CONCRETE_INSTRUCTION(StoreNamedField, "store-named-field")
   DECLARE_HYDROGEN_ACCESSOR(StoreNamedField)
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
   Handle<Map> transition() const { return hydrogen()->transition_map(); }
   Representation representation() const {
@@ -2136,7 +2153,7 @@ class LStoreNamedField: public LTemplateInstruction<0, 2, 1> {
 };
 
 
-class LStoreNamedGeneric: public LTemplateInstruction<0, 2, 0> {
+class LStoreNamedGeneric V8_FINAL : public LTemplateInstruction<0, 2, 0> {
  public:
   LStoreNamedGeneric(LOperand* object, LOperand* value) {
     inputs_[0] = object;
@@ -2149,14 +2166,14 @@ class LStoreNamedGeneric: public LTemplateInstruction<0, 2, 0> {
   DECLARE_CONCRETE_INSTRUCTION(StoreNamedGeneric, "store-named-generic")
   DECLARE_HYDROGEN_ACCESSOR(StoreNamedGeneric)
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
   Handle<Object> name() const { return hydrogen()->name(); }
   StrictModeFlag strict_mode_flag() { return hydrogen()->strict_mode_flag(); }
 };
 
 
-class LStoreKeyed: public LTemplateInstruction<0, 3, 0> {
+class LStoreKeyed V8_FINAL : public LTemplateInstruction<0, 3, 0> {
  public:
   LStoreKeyed(LOperand* object, LOperand* key, LOperand* value) {
     inputs_[0] = object;
@@ -2175,13 +2192,13 @@ class LStoreKeyed: public LTemplateInstruction<0, 3, 0> {
   DECLARE_CONCRETE_INSTRUCTION(StoreKeyed, "store-keyed")
   DECLARE_HYDROGEN_ACCESSOR(StoreKeyed)
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
   bool NeedsCanonicalization() { return hydrogen()->NeedsCanonicalization(); }
   uint32_t additional_index() const { return hydrogen()->index_offset(); }
 };
 
 
-class LStoreKeyedGeneric: public LTemplateInstruction<0, 3, 0> {
+class LStoreKeyedGeneric V8_FINAL : public LTemplateInstruction<0, 3, 0> {
  public:
   LStoreKeyedGeneric(LOperand* obj, LOperand* key, LOperand* value) {
     inputs_[0] = obj;
@@ -2196,13 +2213,13 @@ class LStoreKeyedGeneric: public LTemplateInstruction<0, 3, 0> {
   DECLARE_CONCRETE_INSTRUCTION(StoreKeyedGeneric, "store-keyed-generic")
   DECLARE_HYDROGEN_ACCESSOR(StoreKeyedGeneric)
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
   StrictModeFlag strict_mode_flag() { return hydrogen()->strict_mode_flag(); }
 };
 
 
-class LTransitionElementsKind: public LTemplateInstruction<0, 1, 1> {
+class LTransitionElementsKind V8_FINAL : public LTemplateInstruction<0, 1, 1> {
  public:
   LTransitionElementsKind(LOperand* object,
                           LOperand* new_map_temp) {
@@ -2217,7 +2234,7 @@ class LTransitionElementsKind: public LTemplateInstruction<0, 1, 1> {
                                "transition-elements-kind")
   DECLARE_HYDROGEN_ACCESSOR(TransitionElementsKind)
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
   Handle<Map> original_map() { return hydrogen()->original_map(); }
   Handle<Map> transitioned_map() { return hydrogen()->transitioned_map(); }
@@ -2226,7 +2243,7 @@ class LTransitionElementsKind: public LTemplateInstruction<0, 1, 1> {
 };
 
 
-class LTrapAllocationMemento : public LTemplateInstruction<0, 1, 1> {
+class LTrapAllocationMemento V8_FINAL : public LTemplateInstruction<0, 1, 1> {
  public:
   LTrapAllocationMemento(LOperand* object,
                          LOperand* temp) {
@@ -2242,7 +2259,7 @@ class LTrapAllocationMemento : public LTemplateInstruction<0, 1, 1> {
 };
 
 
-class LStringAdd: public LTemplateInstruction<1, 2, 0> {
+class LStringAdd V8_FINAL : public LTemplateInstruction<1, 2, 0> {
  public:
   LStringAdd(LOperand* left, LOperand* right) {
     inputs_[0] = left;
@@ -2258,7 +2275,7 @@ class LStringAdd: public LTemplateInstruction<1, 2, 0> {
 
 
 
-class LStringCharCodeAt: public LTemplateInstruction<1, 2, 0> {
+class LStringCharCodeAt V8_FINAL : public LTemplateInstruction<1, 2, 0> {
  public:
   LStringCharCodeAt(LOperand* string, LOperand* index) {
     inputs_[0] = string;
@@ -2273,7 +2290,7 @@ class LStringCharCodeAt: public LTemplateInstruction<1, 2, 0> {
 };
 
 
-class LStringCharFromCode: public LTemplateInstruction<1, 1, 0> {
+class LStringCharFromCode V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LStringCharFromCode(LOperand* char_code) {
     inputs_[0] = char_code;
@@ -2286,7 +2303,7 @@ class LStringCharFromCode: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LCheckFunction: public LTemplateInstruction<0, 1, 0> {
+class LCheckFunction V8_FINAL : public LTemplateInstruction<0, 1, 0> {
  public:
   explicit LCheckFunction(LOperand* value) {
     inputs_[0] = value;
@@ -2299,7 +2316,7 @@ class LCheckFunction: public LTemplateInstruction<0, 1, 0> {
 };
 
 
-class LCheckInstanceType: public LTemplateInstruction<0, 1, 0> {
+class LCheckInstanceType V8_FINAL : public LTemplateInstruction<0, 1, 0> {
  public:
   explicit LCheckInstanceType(LOperand* value) {
     inputs_[0] = value;
@@ -2312,7 +2329,7 @@ class LCheckInstanceType: public LTemplateInstruction<0, 1, 0> {
 };
 
 
-class LCheckMaps: public LTemplateInstruction<0, 1, 0> {
+class LCheckMaps V8_FINAL : public LTemplateInstruction<0, 1, 0> {
  public:
   explicit LCheckMaps(LOperand* value) {
     inputs_[0] = value;
@@ -2325,7 +2342,7 @@ class LCheckMaps: public LTemplateInstruction<0, 1, 0> {
 };
 
 
-class LCheckSmi: public LTemplateInstruction<1, 1, 0> {
+class LCheckSmi V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LCheckSmi(LOperand* value) {
     inputs_[0] = value;
@@ -2337,7 +2354,7 @@ class LCheckSmi: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LCheckNonSmi: public LTemplateInstruction<0, 1, 0> {
+class LCheckNonSmi V8_FINAL : public LTemplateInstruction<0, 1, 0> {
  public:
   explicit LCheckNonSmi(LOperand* value) {
     inputs_[0] = value;
@@ -2350,7 +2367,7 @@ class LCheckNonSmi: public LTemplateInstruction<0, 1, 0> {
 };
 
 
-class LClampDToUint8: public LTemplateInstruction<1, 1, 1> {
+class LClampDToUint8 V8_FINAL : public LTemplateInstruction<1, 1, 1> {
  public:
   LClampDToUint8(LOperand* unclamped, LOperand* temp) {
     inputs_[0] = unclamped;
@@ -2364,7 +2381,7 @@ class LClampDToUint8: public LTemplateInstruction<1, 1, 1> {
 };
 
 
-class LClampIToUint8: public LTemplateInstruction<1, 1, 0> {
+class LClampIToUint8 V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LClampIToUint8(LOperand* unclamped) {
     inputs_[0] = unclamped;
@@ -2376,7 +2393,7 @@ class LClampIToUint8: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LClampTToUint8: public LTemplateInstruction<1, 1, 1> {
+class LClampTToUint8 V8_FINAL : public LTemplateInstruction<1, 1, 1> {
  public:
   LClampTToUint8(LOperand* unclamped, LOperand* temp) {
     inputs_[0] = unclamped;
@@ -2390,7 +2407,7 @@ class LClampTToUint8: public LTemplateInstruction<1, 1, 1> {
 };
 
 
-class LAllocate: public LTemplateInstruction<1, 2, 2> {
+class LAllocate V8_FINAL : public LTemplateInstruction<1, 2, 2> {
  public:
   LAllocate(LOperand* size, LOperand* temp1, LOperand* temp2) {
     inputs_[1] = size;
@@ -2407,21 +2424,21 @@ class LAllocate: public LTemplateInstruction<1, 2, 2> {
 };
 
 
-class LRegExpLiteral: public LTemplateInstruction<1, 0, 0> {
+class LRegExpLiteral V8_FINAL : public LTemplateInstruction<1, 0, 0> {
  public:
   DECLARE_CONCRETE_INSTRUCTION(RegExpLiteral, "regexp-literal")
   DECLARE_HYDROGEN_ACCESSOR(RegExpLiteral)
 };
 
 
-class LFunctionLiteral: public LTemplateInstruction<1, 0, 0> {
+class LFunctionLiteral V8_FINAL : public LTemplateInstruction<1, 0, 0> {
  public:
   DECLARE_CONCRETE_INSTRUCTION(FunctionLiteral, "function-literal")
   DECLARE_HYDROGEN_ACCESSOR(FunctionLiteral)
 };
 
 
-class LToFastProperties: public LTemplateInstruction<1, 1, 0> {
+class LToFastProperties V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LToFastProperties(LOperand* value) {
     inputs_[0] = value;
@@ -2434,7 +2451,7 @@ class LToFastProperties: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LTypeof: public LTemplateInstruction<1, 1, 0> {
+class LTypeof V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LTypeof(LOperand* value) {
     inputs_[0] = value;
@@ -2446,7 +2463,7 @@ class LTypeof: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LTypeofIsAndBranch: public LControlInstruction<1, 0> {
+class LTypeofIsAndBranch V8_FINAL : public LControlInstruction<1, 0> {
  public:
   explicit LTypeofIsAndBranch(LOperand* value) {
     inputs_[0] = value;
@@ -2459,11 +2476,11 @@ class LTypeofIsAndBranch: public LControlInstruction<1, 0> {
 
   Handle<String> type_literal() { return hydrogen()->type_literal(); }
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 };
 
 
-class LIsConstructCallAndBranch: public LControlInstruction<0, 1> {
+class LIsConstructCallAndBranch V8_FINAL : public LControlInstruction<0, 1> {
  public:
   explicit LIsConstructCallAndBranch(LOperand* temp) {
     temps_[0] = temp;
@@ -2476,16 +2493,18 @@ class LIsConstructCallAndBranch: public LControlInstruction<0, 1> {
 };
 
 
-class LOsrEntry: public LTemplateInstruction<0, 0, 0> {
+class LOsrEntry V8_FINAL : public LTemplateInstruction<0, 0, 0> {
  public:
   LOsrEntry() {}
 
-  virtual bool HasInterestingComment(LCodeGen* gen) const { return false; }
+  virtual bool HasInterestingComment(LCodeGen* gen) const V8_OVERRIDE {
+    return false;
+  }
   DECLARE_CONCRETE_INSTRUCTION(OsrEntry, "osr-entry")
 };
 
 
-class LStackCheck: public LTemplateInstruction<0, 0, 0> {
+class LStackCheck V8_FINAL : public LTemplateInstruction<0, 0, 0> {
  public:
   DECLARE_CONCRETE_INSTRUCTION(StackCheck, "stack-check")
   DECLARE_HYDROGEN_ACCESSOR(StackCheck)
@@ -2497,7 +2516,7 @@ class LStackCheck: public LTemplateInstruction<0, 0, 0> {
 };
 
 
-class LForInPrepareMap: public LTemplateInstruction<1, 1, 0> {
+class LForInPrepareMap V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LForInPrepareMap(LOperand* object) {
     inputs_[0] = object;
@@ -2509,7 +2528,7 @@ class LForInPrepareMap: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LForInCacheArray: public LTemplateInstruction<1, 1, 0> {
+class LForInCacheArray V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LForInCacheArray(LOperand* map) {
     inputs_[0] = map;
@@ -2525,7 +2544,7 @@ class LForInCacheArray: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LCheckMapValue: public LTemplateInstruction<0, 2, 0> {
+class LCheckMapValue V8_FINAL : public LTemplateInstruction<0, 2, 0> {
  public:
   LCheckMapValue(LOperand* value, LOperand* map) {
     inputs_[0] = value;
@@ -2539,7 +2558,7 @@ class LCheckMapValue: public LTemplateInstruction<0, 2, 0> {
 };
 
 
-class LLoadFieldByIndex: public LTemplateInstruction<1, 2, 0> {
+class LLoadFieldByIndex V8_FINAL : public LTemplateInstruction<1, 2, 0> {
  public:
   LLoadFieldByIndex(LOperand* object, LOperand* index) {
     inputs_[0] = object;
@@ -2554,7 +2573,7 @@ class LLoadFieldByIndex: public LTemplateInstruction<1, 2, 0> {
 
 
 class LChunkBuilder;
-class LPlatformChunk: public LChunk {
+class LPlatformChunk V8_FINAL : public LChunk {
  public:
   LPlatformChunk(CompilationInfo* info, HGraph* graph)
       : LChunk(info, graph) { }
@@ -2564,7 +2583,7 @@ class LPlatformChunk: public LChunk {
 };
 
 
-class LChunkBuilder BASE_EMBEDDED {
+class LChunkBuilder V8_FINAL BASE_EMBEDDED {
  public:
   LChunkBuilder(CompilationInfo* info, HGraph* graph, LAllocator* allocator)
       : chunk_(NULL),
diff --git a/src/x64/lithium-codegen-x64.cc b/src/x64/lithium-codegen-x64.cc
index abb8c77b5b..a1f4ad184b 100644
--- a/src/x64/lithium-codegen-x64.cc
+++ b/src/x64/lithium-codegen-x64.cc
@@ -39,7 +39,7 @@ namespace internal {
 
 // When invoking builtins, we need to record the safepoint in the middle of
 // the invoke instruction sequence generated by the macro assembler.
-class SafepointGenerator : public CallWrapper {
+class SafepointGenerator V8_FINAL : public CallWrapper {
  public:
   SafepointGenerator(LCodeGen* codegen,
                      LPointerMap* pointers,
@@ -47,13 +47,13 @@ class SafepointGenerator : public CallWrapper {
       : codegen_(codegen),
         pointers_(pointers),
         deopt_mode_(mode) { }
-  virtual ~SafepointGenerator() { }
+  virtual ~SafepointGenerator() {}
 
-  virtual void BeforeCall(int call_size) const {
+  virtual void BeforeCall(int call_size) const V8_OVERRIDE {
     codegen_->EnsureSpaceForLazyDeopt(Deoptimizer::patch_size() - call_size);
   }
 
-  virtual void AfterCall() const {
+  virtual void AfterCall() const V8_OVERRIDE {
     codegen_->RecordSafepoint(pointers_, deopt_mode_);
   }
 
@@ -2466,15 +2466,15 @@ void LCodeGen::DoInstanceOf(LInstanceOf* instr) {
 
 
 void LCodeGen::DoInstanceOfKnownGlobal(LInstanceOfKnownGlobal* instr) {
-  class DeferredInstanceOfKnownGlobal: public LDeferredCode {
+  class DeferredInstanceOfKnownGlobal V8_FINAL : public LDeferredCode {
    public:
     DeferredInstanceOfKnownGlobal(LCodeGen* codegen,
                                   LInstanceOfKnownGlobal* instr)
         : LDeferredCode(codegen), instr_(instr) { }
-    virtual void Generate() {
+    virtual void Generate() V8_OVERRIDE {
       codegen()->DoDeferredInstanceOfKnownGlobal(instr_, &map_check_);
     }
-    virtual LInstruction* instr() { return instr_; }
+    virtual LInstruction* instr() V8_OVERRIDE { return instr_; }
     Label* map_check() { return &map_check_; }
    private:
     LInstanceOfKnownGlobal* instr_;
@@ -3400,14 +3400,14 @@ void LCodeGen::EmitSmiMathAbs(LMathAbs* instr) {
 
 void LCodeGen::DoMathAbs(LMathAbs* instr) {
   // Class for deferred case.
-  class DeferredMathAbsTaggedHeapNumber: public LDeferredCode {
+  class DeferredMathAbsTaggedHeapNumber V8_FINAL : public LDeferredCode {
    public:
     DeferredMathAbsTaggedHeapNumber(LCodeGen* codegen, LMathAbs* instr)
         : LDeferredCode(codegen), instr_(instr) { }
-    virtual void Generate() {
+    virtual void Generate() V8_OVERRIDE {
       codegen()->DoDeferredMathAbsTaggedHeapNumber(instr_);
     }
-    virtual LInstruction* instr() { return instr_; }
+    virtual LInstruction* instr() V8_OVERRIDE { return instr_; }
    private:
     LMathAbs* instr_;
   };
@@ -3632,12 +3632,12 @@ void LCodeGen::DoPower(LPower* instr) {
 
 
 void LCodeGen::DoRandom(LRandom* instr) {
-  class DeferredDoRandom: public LDeferredCode {
+  class DeferredDoRandom V8_FINAL : public LDeferredCode {
    public:
     DeferredDoRandom(LCodeGen* codegen, LRandom* instr)
         : LDeferredCode(codegen), instr_(instr) { }
-    virtual void Generate() { codegen()->DoDeferredRandom(instr_); }
-    virtual LInstruction* instr() { return instr_; }
+    virtual void Generate() V8_OVERRIDE { codegen()->DoDeferredRandom(instr_); }
+    virtual LInstruction* instr() V8_OVERRIDE { return instr_; }
    private:
     LRandom* instr_;
   };
@@ -4322,12 +4322,14 @@ void LCodeGen::DoStringAdd(LStringAdd* instr) {
 
 
 void LCodeGen::DoStringCharCodeAt(LStringCharCodeAt* instr) {
-  class DeferredStringCharCodeAt: public LDeferredCode {
+  class DeferredStringCharCodeAt V8_FINAL : public LDeferredCode {
    public:
     DeferredStringCharCodeAt(LCodeGen* codegen, LStringCharCodeAt* instr)
         : LDeferredCode(codegen), instr_(instr) { }
-    virtual void Generate() { codegen()->DoDeferredStringCharCodeAt(instr_); }
-    virtual LInstruction* instr() { return instr_; }
+    virtual void Generate() V8_OVERRIDE {
+      codegen()->DoDeferredStringCharCodeAt(instr_);
+    }
+    virtual LInstruction* instr() V8_OVERRIDE { return instr_; }
    private:
     LStringCharCodeAt* instr_;
   };
@@ -4374,12 +4376,14 @@ void LCodeGen::DoDeferredStringCharCodeAt(LStringCharCodeAt* instr) {
 
 
 void LCodeGen::DoStringCharFromCode(LStringCharFromCode* instr) {
-  class DeferredStringCharFromCode: public LDeferredCode {
+  class DeferredStringCharFromCode V8_FINAL : public LDeferredCode {
    public:
     DeferredStringCharFromCode(LCodeGen* codegen, LStringCharFromCode* instr)
         : LDeferredCode(codegen), instr_(instr) { }
-    virtual void Generate() { codegen()->DoDeferredStringCharFromCode(instr_); }
-    virtual LInstruction* instr() { return instr_; }
+    virtual void Generate() V8_OVERRIDE {
+      codegen()->DoDeferredStringCharFromCode(instr_);
+    }
+    virtual LInstruction* instr() V8_OVERRIDE { return instr_; }
    private:
     LStringCharFromCode* instr_;
   };
@@ -4468,14 +4472,14 @@ void LCodeGen::DoNumberTagI(LNumberTagI* instr) {
 
 
 void LCodeGen::DoNumberTagU(LNumberTagU* instr) {
-  class DeferredNumberTagU: public LDeferredCode {
+  class DeferredNumberTagU V8_FINAL : public LDeferredCode {
    public:
     DeferredNumberTagU(LCodeGen* codegen, LNumberTagU* instr)
         : LDeferredCode(codegen), instr_(instr) { }
-    virtual void Generate() {
+    virtual void Generate() V8_OVERRIDE {
       codegen()->DoDeferredNumberTagU(instr_);
     }
-    virtual LInstruction* instr() { return instr_; }
+    virtual LInstruction* instr() V8_OVERRIDE { return instr_; }
    private:
     LNumberTagU* instr_;
   };
@@ -4531,12 +4535,14 @@ void LCodeGen::DoDeferredNumberTagU(LNumberTagU* instr) {
 
 
 void LCodeGen::DoNumberTagD(LNumberTagD* instr) {
-  class DeferredNumberTagD: public LDeferredCode {
+  class DeferredNumberTagD V8_FINAL : public LDeferredCode {
    public:
     DeferredNumberTagD(LCodeGen* codegen, LNumberTagD* instr)
         : LDeferredCode(codegen), instr_(instr) { }
-    virtual void Generate() { codegen()->DoDeferredNumberTagD(instr_); }
-    virtual LInstruction* instr() { return instr_; }
+    virtual void Generate() V8_OVERRIDE {
+      codegen()->DoDeferredNumberTagD(instr_);
+    }
+    virtual LInstruction* instr() V8_OVERRIDE { return instr_; }
    private:
     LNumberTagD* instr_;
   };
@@ -4698,12 +4704,14 @@ void LCodeGen::DoDeferredTaggedToI(LTaggedToI* instr) {
 
 
 void LCodeGen::DoTaggedToI(LTaggedToI* instr) {
-  class DeferredTaggedToI: public LDeferredCode {
+  class DeferredTaggedToI V8_FINAL : public LDeferredCode {
    public:
     DeferredTaggedToI(LCodeGen* codegen, LTaggedToI* instr)
         : LDeferredCode(codegen), instr_(instr) { }
-    virtual void Generate() { codegen()->DoDeferredTaggedToI(instr_); }
-    virtual LInstruction* instr() { return instr_; }
+    virtual void Generate() V8_OVERRIDE {
+      codegen()->DoDeferredTaggedToI(instr_);
+    }
+    virtual LInstruction* instr() V8_OVERRIDE { return instr_; }
    private:
     LTaggedToI* instr_;
   };
@@ -4900,17 +4908,17 @@ void LCodeGen::DoDeferredInstanceMigration(LCheckMaps* instr, Register object) {
 
 
 void LCodeGen::DoCheckMaps(LCheckMaps* instr) {
-  class DeferredCheckMaps: public LDeferredCode {
+  class DeferredCheckMaps V8_FINAL : public LDeferredCode {
    public:
     DeferredCheckMaps(LCodeGen* codegen, LCheckMaps* instr, Register object)
         : LDeferredCode(codegen), instr_(instr), object_(object) {
       SetExit(check_maps());
     }
-    virtual void Generate() {
+    virtual void Generate() V8_OVERRIDE {
       codegen()->DoDeferredInstanceMigration(instr_, object_);
     }
     Label* check_maps() { return &check_maps_; }
-    virtual LInstruction* instr() { return instr_; }
+    virtual LInstruction* instr() V8_OVERRIDE { return instr_; }
    private:
     LCheckMaps* instr_;
     Label check_maps_;
@@ -5000,12 +5008,14 @@ void LCodeGen::DoClampTToUint8(LClampTToUint8* instr) {
 
 
 void LCodeGen::DoAllocate(LAllocate* instr) {
-  class DeferredAllocate: public LDeferredCode {
+  class DeferredAllocate V8_FINAL : public LDeferredCode {
    public:
     DeferredAllocate(LCodeGen* codegen, LAllocate* instr)
         : LDeferredCode(codegen), instr_(instr) { }
-    virtual void Generate() { codegen()->DoDeferredAllocate(instr_); }
-    virtual LInstruction* instr() { return instr_; }
+    virtual void Generate() V8_OVERRIDE {
+      codegen()->DoDeferredAllocate(instr_);
+    }
+    virtual LInstruction* instr() V8_OVERRIDE { return instr_; }
    private:
     LAllocate* instr_;
   };
@@ -5361,12 +5371,14 @@ void LCodeGen::DoDeferredStackCheck(LStackCheck* instr) {
 
 
 void LCodeGen::DoStackCheck(LStackCheck* instr) {
-  class DeferredStackCheck: public LDeferredCode {
+  class DeferredStackCheck V8_FINAL : public LDeferredCode {
    public:
     DeferredStackCheck(LCodeGen* codegen, LStackCheck* instr)
         : LDeferredCode(codegen), instr_(instr) { }
-    virtual void Generate() { codegen()->DoDeferredStackCheck(instr_); }
-    virtual LInstruction* instr() { return instr_; }
+    virtual void Generate() V8_OVERRIDE {
+      codegen()->DoDeferredStackCheck(instr_);
+    }
+    virtual LInstruction* instr() V8_OVERRIDE { return instr_; }
    private:
     LStackCheck* instr_;
   };
diff --git a/src/x64/lithium-codegen-x64.h b/src/x64/lithium-codegen-x64.h
index a74ec7982c..65c6dcae1f 100644
--- a/src/x64/lithium-codegen-x64.h
+++ b/src/x64/lithium-codegen-x64.h
@@ -44,7 +44,7 @@ namespace internal {
 class LDeferredCode;
 class SafepointGenerator;
 
-class LCodeGen BASE_EMBEDDED {
+class LCodeGen V8_FINAL BASE_EMBEDDED {
  public:
   LCodeGen(LChunk* chunk, MacroAssembler* assembler, CompilationInfo* info)
       : zone_(info->zone()),
@@ -384,7 +384,7 @@ class LCodeGen BASE_EMBEDDED {
 
   int old_position_;
 
-  class PushSafepointRegistersScope BASE_EMBEDDED {
+  class PushSafepointRegistersScope V8_FINAL BASE_EMBEDDED {
    public:
     explicit PushSafepointRegistersScope(LCodeGen* codegen)
         : codegen_(codegen) {
@@ -420,7 +420,7 @@ class LDeferredCode: public ZoneObject {
     codegen->AddDeferredCode(this);
   }
 
-  virtual ~LDeferredCode() { }
+  virtual ~LDeferredCode() {}
   virtual void Generate() = 0;
   virtual LInstruction* instr() = 0;
 
diff --git a/src/x64/lithium-gap-resolver-x64.h b/src/x64/lithium-gap-resolver-x64.h
index d828455921..f218455b67 100644
--- a/src/x64/lithium-gap-resolver-x64.h
+++ b/src/x64/lithium-gap-resolver-x64.h
@@ -38,7 +38,7 @@ namespace internal {
 class LCodeGen;
 class LGapResolver;
 
-class LGapResolver BASE_EMBEDDED {
+class LGapResolver V8_FINAL BASE_EMBEDDED {
  public:
   explicit LGapResolver(LCodeGen* owner);
 
diff --git a/src/x64/lithium-x64.h b/src/x64/lithium-x64.h
index 77bebe64bd..b3a20cf691 100644
--- a/src/x64/lithium-x64.h
+++ b/src/x64/lithium-x64.h
@@ -186,13 +186,17 @@ class LCodeGen;
   V(WrapReceiver)
 
 
-#define DECLARE_CONCRETE_INSTRUCTION(type, mnemonic)              \
-  virtual Opcode opcode() const { return LInstruction::k##type; } \
-  virtual void CompileToNative(LCodeGen* generator);              \
-  virtual const char* Mnemonic() const { return mnemonic; }       \
-  static L##type* cast(LInstruction* instr) {                     \
-    ASSERT(instr->Is##type());                                    \
-    return reinterpret_cast<L##type*>(instr);                     \
+#define DECLARE_CONCRETE_INSTRUCTION(type, mnemonic)                        \
+  virtual Opcode opcode() const V8_FINAL V8_OVERRIDE {                      \
+    return LInstruction::k##type;                                           \
+  }                                                                         \
+  virtual void CompileToNative(LCodeGen* generator) V8_FINAL V8_OVERRIDE;   \
+  virtual const char* Mnemonic() const V8_FINAL V8_OVERRIDE {               \
+    return mnemonic;                                                        \
+  }                                                                         \
+  static L##type* cast(LInstruction* instr) {                               \
+    ASSERT(instr->Is##type());                                              \
+    return reinterpret_cast<L##type*>(instr);                               \
   }
 
 
@@ -202,7 +206,7 @@ class LCodeGen;
   }
 
 
-class LInstruction: public ZoneObject {
+class LInstruction : public ZoneObject {
  public:
   LInstruction()
       : environment_(NULL),
@@ -211,7 +215,7 @@ class LInstruction: public ZoneObject {
     set_position(RelocInfo::kNoPosition);
   }
 
-  virtual ~LInstruction() { }
+  virtual ~LInstruction() {}
 
   virtual void CompileToNative(LCodeGen* generator) = 0;
   virtual const char* Mnemonic() const = 0;
@@ -310,11 +314,13 @@ class LInstruction: public ZoneObject {
 // I = number of input operands.
 // T = number of temporary operands.
 template<int R, int I, int T>
-class LTemplateInstruction: public LInstruction {
+class LTemplateInstruction : public LInstruction {
  public:
   // Allow 0 or 1 output operands.
   STATIC_ASSERT(R == 0 || R == 1);
-  virtual bool HasResult() const { return R != 0 && result() != NULL; }
+  virtual bool HasResult() const V8_FINAL V8_OVERRIDE {
+    return R != 0 && result() != NULL;
+  }
   void set_result(LOperand* operand) { results_[0] = operand; }
   LOperand* result() const { return results_[0]; }
 
@@ -325,15 +331,15 @@ class LTemplateInstruction: public LInstruction {
 
  private:
   // Iterator support.
-  virtual int InputCount() { return I; }
-  virtual LOperand* InputAt(int i) { return inputs_[i]; }
+  virtual int InputCount() V8_FINAL V8_OVERRIDE { return I; }
+  virtual LOperand* InputAt(int i) V8_FINAL V8_OVERRIDE { return inputs_[i]; }
 
-  virtual int TempCount() { return T; }
-  virtual LOperand* TempAt(int i) { return temps_[i]; }
+  virtual int TempCount() V8_FINAL V8_OVERRIDE { return T; }
+  virtual LOperand* TempAt(int i) V8_FINAL V8_OVERRIDE { return temps_[i]; }
 };
 
 
-class LGap: public LTemplateInstruction<0, 0, 0> {
+class LGap : public LTemplateInstruction<0, 0, 0> {
  public:
   explicit LGap(HBasicBlock* block)
       : block_(block) {
@@ -344,8 +350,8 @@ class LGap: public LTemplateInstruction<0, 0, 0> {
   }
 
   // Can't use the DECLARE-macro here because of sub-classes.
-  virtual bool IsGap() const { return true; }
-  virtual void PrintDataTo(StringStream* stream);
+  virtual bool IsGap() const V8_FINAL V8_OVERRIDE { return true; }
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
   static LGap* cast(LInstruction* instr) {
     ASSERT(instr->IsGap());
     return reinterpret_cast<LGap*>(instr);
@@ -382,11 +388,11 @@ class LGap: public LTemplateInstruction<0, 0, 0> {
 };
 
 
-class LInstructionGap: public LGap {
+class LInstructionGap V8_FINAL : public LGap {
  public:
   explicit LInstructionGap(HBasicBlock* block) : LGap(block) { }
 
-  virtual bool HasInterestingComment(LCodeGen* gen) const {
+  virtual bool HasInterestingComment(LCodeGen* gen) const V8_OVERRIDE {
     return !IsRedundant();
   }
 
@@ -394,14 +400,14 @@ class LInstructionGap: public LGap {
 };
 
 
-class LGoto: public LTemplateInstruction<0, 0, 0> {
+class LGoto V8_FINAL : public LTemplateInstruction<0, 0, 0> {
  public:
   explicit LGoto(int block_id) : block_id_(block_id) { }
 
-  virtual bool HasInterestingComment(LCodeGen* gen) const;
+  virtual bool HasInterestingComment(LCodeGen* gen) const V8_OVERRIDE;
   DECLARE_CONCRETE_INSTRUCTION(Goto, "goto")
-  virtual void PrintDataTo(StringStream* stream);
-  virtual bool IsControl() const { return true; }
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
+  virtual bool IsControl() const V8_OVERRIDE { return true; }
 
   int block_id() const { return block_id_; }
 
@@ -410,7 +416,7 @@ class LGoto: public LTemplateInstruction<0, 0, 0> {
 };
 
 
-class LLazyBailout: public LTemplateInstruction<0, 0, 0> {
+class LLazyBailout V8_FINAL : public LTemplateInstruction<0, 0, 0> {
  public:
   LLazyBailout() : gap_instructions_size_(0) { }
 
@@ -426,7 +432,7 @@ class LLazyBailout: public LTemplateInstruction<0, 0, 0> {
 };
 
 
-class LDummyUse: public LTemplateInstruction<1, 1, 0> {
+class LDummyUse V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LDummyUse(LOperand* value) {
     inputs_[0] = value;
@@ -435,22 +441,24 @@ class LDummyUse: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LDeoptimize: public LTemplateInstruction<0, 0, 0> {
+class LDeoptimize V8_FINAL : public LTemplateInstruction<0, 0, 0> {
  public:
   DECLARE_CONCRETE_INSTRUCTION(Deoptimize, "deoptimize")
   DECLARE_HYDROGEN_ACCESSOR(Deoptimize)
 };
 
 
-class LLabel: public LGap {
+class LLabel V8_FINAL : public LGap {
  public:
   explicit LLabel(HBasicBlock* block)
       : LGap(block), replacement_(NULL) { }
 
-  virtual bool HasInterestingComment(LCodeGen* gen) const { return false; }
+  virtual bool HasInterestingComment(LCodeGen* gen) const V8_OVERRIDE {
+    return false;
+  }
   DECLARE_CONCRETE_INSTRUCTION(Label, "label")
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
   int block_id() const { return block()->block_id(); }
   bool is_loop_header() const { return block()->IsLoopHeader(); }
@@ -466,14 +474,16 @@ class LLabel: public LGap {
 };
 
 
-class LParameter: public LTemplateInstruction<1, 0, 0> {
+class LParameter V8_FINAL : public LTemplateInstruction<1, 0, 0> {
  public:
-  virtual bool HasInterestingComment(LCodeGen* gen) const { return false; }
+  virtual bool HasInterestingComment(LCodeGen* gen) const V8_OVERRIDE {
+    return false;
+  }
   DECLARE_CONCRETE_INSTRUCTION(Parameter, "parameter")
 };
 
 
-class LCallStub: public LTemplateInstruction<1, 0, 0> {
+class LCallStub V8_FINAL : public LTemplateInstruction<1, 0, 0> {
  public:
   DECLARE_CONCRETE_INSTRUCTION(CallStub, "call-stub")
   DECLARE_HYDROGEN_ACCESSOR(CallStub)
@@ -484,19 +494,21 @@ class LCallStub: public LTemplateInstruction<1, 0, 0> {
 };
 
 
-class LUnknownOSRValue: public LTemplateInstruction<1, 0, 0> {
+class LUnknownOSRValue V8_FINAL : public LTemplateInstruction<1, 0, 0> {
  public:
-  virtual bool HasInterestingComment(LCodeGen* gen) const { return false; }
+  virtual bool HasInterestingComment(LCodeGen* gen) const V8_OVERRIDE {
+    return false;
+  }
   DECLARE_CONCRETE_INSTRUCTION(UnknownOSRValue, "unknown-osr-value")
 };
 
 
 template<int I, int T>
-class LControlInstruction: public LTemplateInstruction<0, I, T> {
+class LControlInstruction : public LTemplateInstruction<0, I, T> {
  public:
   LControlInstruction() : false_label_(NULL), true_label_(NULL) { }
 
-  virtual bool IsControl() const { return true; }
+  virtual bool IsControl() const V8_FINAL V8_OVERRIDE { return true; }
 
   int SuccessorCount() { return hydrogen()->SuccessorCount(); }
   HBasicBlock* SuccessorAt(int i) { return hydrogen()->SuccessorAt(i); }
@@ -535,7 +547,7 @@ class LControlInstruction: public LTemplateInstruction<0, I, T> {
 };
 
 
-class LWrapReceiver: public LTemplateInstruction<1, 2, 0> {
+class LWrapReceiver V8_FINAL : public LTemplateInstruction<1, 2, 0> {
  public:
   LWrapReceiver(LOperand* receiver, LOperand* function) {
     inputs_[0] = receiver;
@@ -549,7 +561,7 @@ class LWrapReceiver: public LTemplateInstruction<1, 2, 0> {
 };
 
 
-class LApplyArguments: public LTemplateInstruction<1, 4, 0> {
+class LApplyArguments V8_FINAL : public LTemplateInstruction<1, 4, 0> {
  public:
   LApplyArguments(LOperand* function,
                   LOperand* receiver,
@@ -570,7 +582,7 @@ class LApplyArguments: public LTemplateInstruction<1, 4, 0> {
 };
 
 
-class LAccessArgumentsAt: public LTemplateInstruction<1, 3, 0> {
+class LAccessArgumentsAt V8_FINAL : public LTemplateInstruction<1, 3, 0> {
  public:
   LAccessArgumentsAt(LOperand* arguments, LOperand* length, LOperand* index) {
     inputs_[0] = arguments;
@@ -584,11 +596,11 @@ class LAccessArgumentsAt: public LTemplateInstruction<1, 3, 0> {
 
   DECLARE_CONCRETE_INSTRUCTION(AccessArgumentsAt, "access-arguments-at")
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 };
 
 
-class LArgumentsLength: public LTemplateInstruction<1, 1, 0> {
+class LArgumentsLength V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LArgumentsLength(LOperand* elements) {
     inputs_[0] = elements;
@@ -600,14 +612,14 @@ class LArgumentsLength: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LArgumentsElements: public LTemplateInstruction<1, 0, 0> {
+class LArgumentsElements V8_FINAL : public LTemplateInstruction<1, 0, 0> {
  public:
   DECLARE_CONCRETE_INSTRUCTION(ArgumentsElements, "arguments-elements")
   DECLARE_HYDROGEN_ACCESSOR(ArgumentsElements)
 };
 
 
-class LModI: public LTemplateInstruction<1, 2, 1> {
+class LModI V8_FINAL : public LTemplateInstruction<1, 2, 1> {
  public:
   LModI(LOperand* left, LOperand* right, LOperand* temp) {
     inputs_[0] = left;
@@ -624,7 +636,7 @@ class LModI: public LTemplateInstruction<1, 2, 1> {
 };
 
 
-class LDivI: public LTemplateInstruction<1, 2, 1> {
+class LDivI V8_FINAL : public LTemplateInstruction<1, 2, 1> {
  public:
   LDivI(LOperand* left, LOperand* right, LOperand* temp) {
     inputs_[0] = left;
@@ -643,7 +655,7 @@ class LDivI: public LTemplateInstruction<1, 2, 1> {
 };
 
 
-class LMathFloorOfDiv: public LTemplateInstruction<1, 2, 1> {
+class LMathFloorOfDiv V8_FINAL : public LTemplateInstruction<1, 2, 1> {
  public:
   LMathFloorOfDiv(LOperand* left,
                   LOperand* right,
@@ -662,7 +674,7 @@ class LMathFloorOfDiv: public LTemplateInstruction<1, 2, 1> {
 };
 
 
-class LMulI: public LTemplateInstruction<1, 2, 0> {
+class LMulI V8_FINAL : public LTemplateInstruction<1, 2, 0> {
  public:
   LMulI(LOperand* left, LOperand* right) {
     inputs_[0] = left;
@@ -677,7 +689,7 @@ class LMulI: public LTemplateInstruction<1, 2, 0> {
 };
 
 
-class LCompareNumericAndBranch: public LControlInstruction<2, 0> {
+class LCompareNumericAndBranch V8_FINAL : public LControlInstruction<2, 0> {
  public:
   LCompareNumericAndBranch(LOperand* left, LOperand* right) {
     inputs_[0] = left;
@@ -696,11 +708,11 @@ class LCompareNumericAndBranch: public LControlInstruction<2, 0> {
     return hydrogen()->representation().IsDouble();
   }
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 };
 
 
-class LMathFloor: public LTemplateInstruction<1, 1, 0> {
+class LMathFloor V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LMathFloor(LOperand* value) {
     inputs_[0] = value;
@@ -713,7 +725,7 @@ class LMathFloor: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LMathRound: public LTemplateInstruction<1, 1, 0> {
+class LMathRound V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LMathRound(LOperand* value) {
     inputs_[0] = value;
@@ -726,7 +738,7 @@ class LMathRound: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LMathAbs: public LTemplateInstruction<1, 1, 0> {
+class LMathAbs V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LMathAbs(LOperand* value) {
     inputs_[0] = value;
@@ -739,7 +751,7 @@ class LMathAbs: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LMathLog: public LTemplateInstruction<1, 1, 0> {
+class LMathLog V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LMathLog(LOperand* value) {
     inputs_[0] = value;
@@ -751,7 +763,7 @@ class LMathLog: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LMathSin: public LTemplateInstruction<1, 1, 0> {
+class LMathSin V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LMathSin(LOperand* value) {
     inputs_[0] = value;
@@ -763,7 +775,7 @@ class LMathSin: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LMathCos: public LTemplateInstruction<1, 1, 0> {
+class LMathCos V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LMathCos(LOperand* value) {
     inputs_[0] = value;
@@ -775,7 +787,7 @@ class LMathCos: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LMathTan: public LTemplateInstruction<1, 1, 0> {
+class LMathTan V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LMathTan(LOperand* value) {
     inputs_[0] = value;
@@ -787,7 +799,7 @@ class LMathTan: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LMathExp: public LTemplateInstruction<1, 1, 2> {
+class LMathExp V8_FINAL : public LTemplateInstruction<1, 1, 2> {
  public:
   LMathExp(LOperand* value, LOperand* temp1, LOperand* temp2) {
     inputs_[0] = value;
@@ -804,7 +816,7 @@ class LMathExp: public LTemplateInstruction<1, 1, 2> {
 };
 
 
-class LMathSqrt: public LTemplateInstruction<1, 1, 0> {
+class LMathSqrt V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LMathSqrt(LOperand* value) {
     inputs_[0] = value;
@@ -816,7 +828,7 @@ class LMathSqrt: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LMathPowHalf: public LTemplateInstruction<1, 1, 0> {
+class LMathPowHalf V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LMathPowHalf(LOperand* value) {
     inputs_[0] = value;
@@ -828,7 +840,7 @@ class LMathPowHalf: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LCmpObjectEqAndBranch: public LControlInstruction<2, 0> {
+class LCmpObjectEqAndBranch V8_FINAL : public LControlInstruction<2, 0> {
  public:
   LCmpObjectEqAndBranch(LOperand* left, LOperand* right) {
     inputs_[0] = left;
@@ -842,7 +854,7 @@ class LCmpObjectEqAndBranch: public LControlInstruction<2, 0> {
 };
 
 
-class LCmpHoleAndBranch: public LControlInstruction<1, 0> {
+class LCmpHoleAndBranch V8_FINAL : public LControlInstruction<1, 0> {
  public:
   explicit LCmpHoleAndBranch(LOperand* object) {
     inputs_[0] = object;
@@ -855,7 +867,7 @@ class LCmpHoleAndBranch: public LControlInstruction<1, 0> {
 };
 
 
-class LIsObjectAndBranch: public LControlInstruction<1, 0> {
+class LIsObjectAndBranch V8_FINAL : public LControlInstruction<1, 0> {
  public:
   explicit LIsObjectAndBranch(LOperand* value) {
     inputs_[0] = value;
@@ -866,11 +878,11 @@ class LIsObjectAndBranch: public LControlInstruction<1, 0> {
   DECLARE_CONCRETE_INSTRUCTION(IsObjectAndBranch, "is-object-and-branch")
   DECLARE_HYDROGEN_ACCESSOR(IsObjectAndBranch)
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 };
 
 
-class LIsNumberAndBranch: public LControlInstruction<1, 0> {
+class LIsNumberAndBranch V8_FINAL : public LControlInstruction<1, 0> {
  public:
   explicit LIsNumberAndBranch(LOperand* value) {
     inputs_[0] = value;
@@ -883,7 +895,7 @@ class LIsNumberAndBranch: public LControlInstruction<1, 0> {
 };
 
 
-class LIsStringAndBranch: public LControlInstruction<1, 1> {
+class LIsStringAndBranch V8_FINAL : public LControlInstruction<1, 1> {
  public:
   explicit LIsStringAndBranch(LOperand* value, LOperand* temp) {
     inputs_[0] = value;
@@ -896,11 +908,11 @@ class LIsStringAndBranch: public LControlInstruction<1, 1> {
   DECLARE_CONCRETE_INSTRUCTION(IsStringAndBranch, "is-string-and-branch")
   DECLARE_HYDROGEN_ACCESSOR(IsStringAndBranch)
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 };
 
 
-class LIsSmiAndBranch: public LControlInstruction<1, 0> {
+class LIsSmiAndBranch V8_FINAL : public LControlInstruction<1, 0> {
  public:
   explicit LIsSmiAndBranch(LOperand* value) {
     inputs_[0] = value;
@@ -911,11 +923,11 @@ class LIsSmiAndBranch: public LControlInstruction<1, 0> {
   DECLARE_CONCRETE_INSTRUCTION(IsSmiAndBranch, "is-smi-and-branch")
   DECLARE_HYDROGEN_ACCESSOR(IsSmiAndBranch)
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 };
 
 
-class LIsUndetectableAndBranch: public LControlInstruction<1, 1> {
+class LIsUndetectableAndBranch V8_FINAL : public LControlInstruction<1, 1> {
  public:
   explicit LIsUndetectableAndBranch(LOperand* value, LOperand* temp) {
     inputs_[0] = value;
@@ -929,11 +941,11 @@ class LIsUndetectableAndBranch: public LControlInstruction<1, 1> {
                                "is-undetectable-and-branch")
   DECLARE_HYDROGEN_ACCESSOR(IsUndetectableAndBranch)
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 };
 
 
-class LStringCompareAndBranch: public LControlInstruction<2, 0> {
+class LStringCompareAndBranch V8_FINAL : public LControlInstruction<2, 0> {
  public:
   explicit LStringCompareAndBranch(LOperand* left, LOperand* right) {
     inputs_[0] = left;
@@ -947,13 +959,13 @@ class LStringCompareAndBranch: public LControlInstruction<2, 0> {
                                "string-compare-and-branch")
   DECLARE_HYDROGEN_ACCESSOR(StringCompareAndBranch)
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
   Token::Value op() const { return hydrogen()->token(); }
 };
 
 
-class LHasInstanceTypeAndBranch: public LControlInstruction<1, 0> {
+class LHasInstanceTypeAndBranch V8_FINAL : public LControlInstruction<1, 0> {
  public:
   explicit LHasInstanceTypeAndBranch(LOperand* value) {
     inputs_[0] = value;
@@ -965,11 +977,11 @@ class LHasInstanceTypeAndBranch: public LControlInstruction<1, 0> {
                                "has-instance-type-and-branch")
   DECLARE_HYDROGEN_ACCESSOR(HasInstanceTypeAndBranch)
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 };
 
 
-class LGetCachedArrayIndex: public LTemplateInstruction<1, 1, 0> {
+class LGetCachedArrayIndex V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LGetCachedArrayIndex(LOperand* value) {
     inputs_[0] = value;
@@ -982,7 +994,8 @@ class LGetCachedArrayIndex: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LHasCachedArrayIndexAndBranch: public LControlInstruction<1, 0> {
+class LHasCachedArrayIndexAndBranch V8_FINAL
+    : public LControlInstruction<1, 0> {
  public:
   explicit LHasCachedArrayIndexAndBranch(LOperand* value) {
     inputs_[0] = value;
@@ -994,11 +1007,11 @@ class LHasCachedArrayIndexAndBranch: public LControlInstruction<1, 0> {
                                "has-cached-array-index-and-branch")
   DECLARE_HYDROGEN_ACCESSOR(HasCachedArrayIndexAndBranch)
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 };
 
 
-class LClassOfTestAndBranch: public LControlInstruction<1, 2> {
+class LClassOfTestAndBranch V8_FINAL : public LControlInstruction<1, 2> {
  public:
   LClassOfTestAndBranch(LOperand* value, LOperand* temp, LOperand* temp2) {
     inputs_[0] = value;
@@ -1014,11 +1027,11 @@ class LClassOfTestAndBranch: public LControlInstruction<1, 2> {
                                "class-of-test-and-branch")
   DECLARE_HYDROGEN_ACCESSOR(ClassOfTestAndBranch)
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 };
 
 
-class LCmpT: public LTemplateInstruction<1, 2, 0> {
+class LCmpT V8_FINAL : public LTemplateInstruction<1, 2, 0> {
  public:
   LCmpT(LOperand* left, LOperand* right) {
     inputs_[0] = left;
@@ -1035,7 +1048,7 @@ class LCmpT: public LTemplateInstruction<1, 2, 0> {
 };
 
 
-class LInstanceOf: public LTemplateInstruction<1, 2, 0> {
+class LInstanceOf V8_FINAL : public LTemplateInstruction<1, 2, 0> {
  public:
   LInstanceOf(LOperand* left, LOperand* right) {
     inputs_[0] = left;
@@ -1049,7 +1062,7 @@ class LInstanceOf: public LTemplateInstruction<1, 2, 0> {
 };
 
 
-class LInstanceOfKnownGlobal: public LTemplateInstruction<1, 1, 1> {
+class LInstanceOfKnownGlobal V8_FINAL : public LTemplateInstruction<1, 1, 1> {
  public:
   LInstanceOfKnownGlobal(LOperand* value, LOperand* temp) {
     inputs_[0] = value;
@@ -1067,7 +1080,8 @@ class LInstanceOfKnownGlobal: public LTemplateInstruction<1, 1, 1> {
   LEnvironment* GetDeferredLazyDeoptimizationEnvironment() {
     return lazy_deopt_env_;
   }
-  virtual void SetDeferredLazyDeoptimizationEnvironment(LEnvironment* env) {
+  virtual void SetDeferredLazyDeoptimizationEnvironment(
+      LEnvironment* env) V8_OVERRIDE {
     lazy_deopt_env_ = env;
   }
 
@@ -1076,7 +1090,7 @@ class LInstanceOfKnownGlobal: public LTemplateInstruction<1, 1, 1> {
 };
 
 
-class LInstanceSize: public LTemplateInstruction<1, 1, 0> {
+class LInstanceSize V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LInstanceSize(LOperand* object) {
     inputs_[0] = object;
@@ -1089,7 +1103,7 @@ class LInstanceSize: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LBoundsCheck: public LTemplateInstruction<0, 2, 0> {
+class LBoundsCheck V8_FINAL : public LTemplateInstruction<0, 2, 0> {
  public:
   LBoundsCheck(LOperand* index, LOperand* length) {
     inputs_[0] = index;
@@ -1104,7 +1118,7 @@ class LBoundsCheck: public LTemplateInstruction<0, 2, 0> {
 };
 
 
-class LBitI: public LTemplateInstruction<1, 2, 0> {
+class LBitI V8_FINAL : public LTemplateInstruction<1, 2, 0> {
  public:
   LBitI(LOperand* left, LOperand* right) {
     inputs_[0] = left;
@@ -1121,7 +1135,7 @@ class LBitI: public LTemplateInstruction<1, 2, 0> {
 };
 
 
-class LShiftI: public LTemplateInstruction<1, 2, 0> {
+class LShiftI V8_FINAL : public LTemplateInstruction<1, 2, 0> {
  public:
   LShiftI(Token::Value op, LOperand* left, LOperand* right, bool can_deopt)
       : op_(op), can_deopt_(can_deopt) {
@@ -1142,7 +1156,7 @@ class LShiftI: public LTemplateInstruction<1, 2, 0> {
 };
 
 
-class LSubI: public LTemplateInstruction<1, 2, 0> {
+class LSubI V8_FINAL : public LTemplateInstruction<1, 2, 0> {
  public:
   LSubI(LOperand* left, LOperand* right) {
     inputs_[0] = left;
@@ -1157,7 +1171,7 @@ class LSubI: public LTemplateInstruction<1, 2, 0> {
 };
 
 
-class LConstantI: public LTemplateInstruction<1, 0, 0> {
+class LConstantI V8_FINAL : public LTemplateInstruction<1, 0, 0> {
  public:
   DECLARE_CONCRETE_INSTRUCTION(ConstantI, "constant-i")
   DECLARE_HYDROGEN_ACCESSOR(Constant)
@@ -1166,7 +1180,7 @@ class LConstantI: public LTemplateInstruction<1, 0, 0> {
 };
 
 
-class LConstantS: public LTemplateInstruction<1, 0, 0> {
+class LConstantS V8_FINAL : public LTemplateInstruction<1, 0, 0> {
  public:
   DECLARE_CONCRETE_INSTRUCTION(ConstantS, "constant-s")
   DECLARE_HYDROGEN_ACCESSOR(Constant)
@@ -1175,7 +1189,7 @@ class LConstantS: public LTemplateInstruction<1, 0, 0> {
 };
 
 
-class LConstantD: public LTemplateInstruction<1, 0, 1> {
+class LConstantD V8_FINAL : public LTemplateInstruction<1, 0, 1> {
  public:
   explicit LConstantD(LOperand* temp) {
     temps_[0] = temp;
@@ -1190,7 +1204,7 @@ class LConstantD: public LTemplateInstruction<1, 0, 1> {
 };
 
 
-class LConstantE: public LTemplateInstruction<1, 0, 0> {
+class LConstantE V8_FINAL : public LTemplateInstruction<1, 0, 0> {
  public:
   DECLARE_CONCRETE_INSTRUCTION(ConstantE, "constant-e")
   DECLARE_HYDROGEN_ACCESSOR(Constant)
@@ -1201,7 +1215,7 @@ class LConstantE: public LTemplateInstruction<1, 0, 0> {
 };
 
 
-class LConstantT: public LTemplateInstruction<1, 0, 0> {
+class LConstantT V8_FINAL : public LTemplateInstruction<1, 0, 0> {
  public:
   DECLARE_CONCRETE_INSTRUCTION(ConstantT, "constant-t")
   DECLARE_HYDROGEN_ACCESSOR(Constant)
@@ -1210,7 +1224,7 @@ class LConstantT: public LTemplateInstruction<1, 0, 0> {
 };
 
 
-class LBranch: public LControlInstruction<1, 0> {
+class LBranch V8_FINAL : public LControlInstruction<1, 0> {
  public:
   explicit LBranch(LOperand* value) {
     inputs_[0] = value;
@@ -1221,17 +1235,17 @@ class LBranch: public LControlInstruction<1, 0> {
   DECLARE_CONCRETE_INSTRUCTION(Branch, "branch")
   DECLARE_HYDROGEN_ACCESSOR(Branch)
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 };
 
 
-class LDebugBreak: public LTemplateInstruction<0, 0, 0> {
+class LDebugBreak V8_FINAL : public LTemplateInstruction<0, 0, 0> {
  public:
   DECLARE_CONCRETE_INSTRUCTION(DebugBreak, "break")
 };
 
 
-class LCmpMapAndBranch: public LControlInstruction<1, 0> {
+class LCmpMapAndBranch V8_FINAL : public LControlInstruction<1, 0> {
  public:
   explicit LCmpMapAndBranch(LOperand* value) {
     inputs_[0] = value;
@@ -1246,7 +1260,7 @@ class LCmpMapAndBranch: public LControlInstruction<1, 0> {
 };
 
 
-class LMapEnumLength: public LTemplateInstruction<1, 1, 0> {
+class LMapEnumLength V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LMapEnumLength(LOperand* value) {
     inputs_[0] = value;
@@ -1258,7 +1272,7 @@ class LMapEnumLength: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LElementsKind: public LTemplateInstruction<1, 1, 0> {
+class LElementsKind V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LElementsKind(LOperand* value) {
     inputs_[0] = value;
@@ -1271,7 +1285,7 @@ class LElementsKind: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LValueOf: public LTemplateInstruction<1, 1, 0> {
+class LValueOf V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LValueOf(LOperand* value) {
     inputs_[0] = value;
@@ -1284,7 +1298,7 @@ class LValueOf: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LDateField: public LTemplateInstruction<1, 1, 0> {
+class LDateField V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   LDateField(LOperand* date, Smi* index) : index_(index) {
     inputs_[0] = date;
@@ -1301,7 +1315,7 @@ class LDateField: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LSeqStringSetChar: public LTemplateInstruction<1, 3, 0> {
+class LSeqStringSetChar V8_FINAL : public LTemplateInstruction<1, 3, 0> {
  public:
   LSeqStringSetChar(String::Encoding encoding,
                     LOperand* string,
@@ -1325,7 +1339,7 @@ class LSeqStringSetChar: public LTemplateInstruction<1, 3, 0> {
 };
 
 
-class LThrow: public LTemplateInstruction<0, 1, 0> {
+class LThrow V8_FINAL : public LTemplateInstruction<0, 1, 0> {
  public:
   explicit LThrow(LOperand* value) {
     inputs_[0] = value;
@@ -1337,7 +1351,7 @@ class LThrow: public LTemplateInstruction<0, 1, 0> {
 };
 
 
-class LAddI: public LTemplateInstruction<1, 2, 0> {
+class LAddI V8_FINAL : public LTemplateInstruction<1, 2, 0> {
  public:
   LAddI(LOperand* left, LOperand* right) {
     inputs_[0] = left;
@@ -1357,7 +1371,7 @@ class LAddI: public LTemplateInstruction<1, 2, 0> {
 };
 
 
-class LMathMinMax: public LTemplateInstruction<1, 2, 0> {
+class LMathMinMax V8_FINAL : public LTemplateInstruction<1, 2, 0> {
  public:
   LMathMinMax(LOperand* left, LOperand* right) {
     inputs_[0] = left;
@@ -1372,7 +1386,7 @@ class LMathMinMax: public LTemplateInstruction<1, 2, 0> {
 };
 
 
-class LPower: public LTemplateInstruction<1, 2, 0> {
+class LPower V8_FINAL : public LTemplateInstruction<1, 2, 0> {
  public:
   LPower(LOperand* left, LOperand* right) {
     inputs_[0] = left;
@@ -1387,7 +1401,7 @@ class LPower: public LTemplateInstruction<1, 2, 0> {
 };
 
 
-class LRandom: public LTemplateInstruction<1, 1, 0> {
+class LRandom V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LRandom(LOperand* global_object) {
     inputs_[0] = global_object;
@@ -1400,7 +1414,7 @@ class LRandom: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LArithmeticD: public LTemplateInstruction<1, 2, 0> {
+class LArithmeticD V8_FINAL : public LTemplateInstruction<1, 2, 0> {
  public:
   LArithmeticD(Token::Value op, LOperand* left, LOperand* right)
       : op_(op) {
@@ -1412,16 +1426,18 @@ class LArithmeticD: public LTemplateInstruction<1, 2, 0> {
   LOperand* left() { return inputs_[0]; }
   LOperand* right() { return inputs_[1]; }
 
-  virtual Opcode opcode() const { return LInstruction::kArithmeticD; }
-  virtual void CompileToNative(LCodeGen* generator);
-  virtual const char* Mnemonic() const;
+  virtual Opcode opcode() const V8_OVERRIDE {
+    return LInstruction::kArithmeticD;
+  }
+  virtual void CompileToNative(LCodeGen* generator) V8_OVERRIDE;
+  virtual const char* Mnemonic() const V8_OVERRIDE;
 
  private:
   Token::Value op_;
 };
 
 
-class LArithmeticT: public LTemplateInstruction<1, 2, 0> {
+class LArithmeticT V8_FINAL : public LTemplateInstruction<1, 2, 0> {
  public:
   LArithmeticT(Token::Value op, LOperand* left, LOperand* right)
       : op_(op) {
@@ -1433,16 +1449,18 @@ class LArithmeticT: public LTemplateInstruction<1, 2, 0> {
   LOperand* left() { return inputs_[0]; }
   LOperand* right() { return inputs_[1]; }
 
-  virtual Opcode opcode() const { return LInstruction::kArithmeticT; }
-  virtual void CompileToNative(LCodeGen* generator);
-  virtual const char* Mnemonic() const;
+  virtual Opcode opcode() const V8_OVERRIDE {
+    return LInstruction::kArithmeticT;
+  }
+  virtual void CompileToNative(LCodeGen* generator) V8_OVERRIDE;
+  virtual const char* Mnemonic() const V8_OVERRIDE;
 
  private:
   Token::Value op_;
 };
 
 
-class LReturn: public LTemplateInstruction<0, 2, 0> {
+class LReturn V8_FINAL : public LTemplateInstruction<0, 2, 0> {
  public:
   explicit LReturn(LOperand* value, LOperand* parameter_count) {
     inputs_[0] = value;
@@ -1465,7 +1483,7 @@ class LReturn: public LTemplateInstruction<0, 2, 0> {
 };
 
 
-class LLoadNamedField: public LTemplateInstruction<1, 1, 0> {
+class LLoadNamedField V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LLoadNamedField(LOperand* object) {
     inputs_[0] = object;
@@ -1478,7 +1496,7 @@ class LLoadNamedField: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LLoadNamedGeneric: public LTemplateInstruction<1, 1, 0> {
+class LLoadNamedGeneric V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LLoadNamedGeneric(LOperand* object) {
     inputs_[0] = object;
@@ -1492,7 +1510,7 @@ class LLoadNamedGeneric: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LLoadFunctionPrototype: public LTemplateInstruction<1, 1, 0> {
+class LLoadFunctionPrototype V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LLoadFunctionPrototype(LOperand* function) {
     inputs_[0] = function;
@@ -1505,7 +1523,8 @@ class LLoadFunctionPrototype: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LLoadExternalArrayPointer: public LTemplateInstruction<1, 1, 0> {
+class LLoadExternalArrayPointer V8_FINAL
+    : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LLoadExternalArrayPointer(LOperand* object) {
     inputs_[0] = object;
@@ -1518,7 +1537,7 @@ class LLoadExternalArrayPointer: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LLoadKeyed: public LTemplateInstruction<1, 2, 0> {
+class LLoadKeyed V8_FINAL : public LTemplateInstruction<1, 2, 0> {
  public:
   LLoadKeyed(LOperand* elements, LOperand* key) {
     inputs_[0] = elements;
@@ -1533,7 +1552,7 @@ class LLoadKeyed: public LTemplateInstruction<1, 2, 0> {
   }
   LOperand* elements() { return inputs_[0]; }
   LOperand* key() { return inputs_[1]; }
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
   uint32_t additional_index() const { return hydrogen()->index_offset(); }
   ElementsKind elements_kind() const {
     return hydrogen()->elements_kind();
@@ -1541,7 +1560,7 @@ class LLoadKeyed: public LTemplateInstruction<1, 2, 0> {
 };
 
 
-class LLoadKeyedGeneric: public LTemplateInstruction<1, 2, 0> {
+class LLoadKeyedGeneric V8_FINAL : public LTemplateInstruction<1, 2, 0> {
  public:
   LLoadKeyedGeneric(LOperand* obj, LOperand* key) {
     inputs_[0] = obj;
@@ -1555,14 +1574,14 @@ class LLoadKeyedGeneric: public LTemplateInstruction<1, 2, 0> {
 };
 
 
-class LLoadGlobalCell: public LTemplateInstruction<1, 0, 0> {
+class LLoadGlobalCell V8_FINAL : public LTemplateInstruction<1, 0, 0> {
  public:
   DECLARE_CONCRETE_INSTRUCTION(LoadGlobalCell, "load-global-cell")
   DECLARE_HYDROGEN_ACCESSOR(LoadGlobalCell)
 };
 
 
-class LLoadGlobalGeneric: public LTemplateInstruction<1, 1, 0> {
+class LLoadGlobalGeneric V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LLoadGlobalGeneric(LOperand* global_object) {
     inputs_[0] = global_object;
@@ -1577,7 +1596,7 @@ class LLoadGlobalGeneric: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LStoreGlobalCell: public LTemplateInstruction<0, 1, 1> {
+class LStoreGlobalCell V8_FINAL : public LTemplateInstruction<0, 1, 1> {
  public:
   explicit LStoreGlobalCell(LOperand* value, LOperand* temp) {
     inputs_[0] = value;
@@ -1592,7 +1611,7 @@ class LStoreGlobalCell: public LTemplateInstruction<0, 1, 1> {
 };
 
 
-class LStoreGlobalGeneric: public LTemplateInstruction<0, 2, 0> {
+class LStoreGlobalGeneric V8_FINAL : public LTemplateInstruction<0, 2, 0> {
  public:
   explicit LStoreGlobalGeneric(LOperand* global_object,
                                LOperand* value) {
@@ -1611,7 +1630,7 @@ class LStoreGlobalGeneric: public LTemplateInstruction<0, 2, 0> {
 };
 
 
-class LLoadContextSlot: public LTemplateInstruction<1, 1, 0> {
+class LLoadContextSlot V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LLoadContextSlot(LOperand* context) {
     inputs_[0] = context;
@@ -1624,11 +1643,11 @@ class LLoadContextSlot: public LTemplateInstruction<1, 1, 0> {
 
   int slot_index() { return hydrogen()->slot_index(); }
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 };
 
 
-class LStoreContextSlot: public LTemplateInstruction<0, 2, 1> {
+class LStoreContextSlot V8_FINAL : public LTemplateInstruction<0, 2, 1> {
  public:
   LStoreContextSlot(LOperand* context, LOperand* value, LOperand* temp) {
     inputs_[0] = context;
@@ -1645,11 +1664,11 @@ class LStoreContextSlot: public LTemplateInstruction<0, 2, 1> {
 
   int slot_index() { return hydrogen()->slot_index(); }
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 };
 
 
-class LPushArgument: public LTemplateInstruction<0, 1, 0> {
+class LPushArgument V8_FINAL : public LTemplateInstruction<0, 1, 0> {
  public:
   explicit LPushArgument(LOperand* value) {
     inputs_[0] = value;
@@ -1661,7 +1680,7 @@ class LPushArgument: public LTemplateInstruction<0, 1, 0> {
 };
 
 
-class LDrop: public LTemplateInstruction<0, 0, 0> {
+class LDrop V8_FINAL : public LTemplateInstruction<0, 0, 0> {
  public:
   explicit LDrop(int count) : count_(count) { }
 
@@ -1674,7 +1693,7 @@ class LDrop: public LTemplateInstruction<0, 0, 0> {
 };
 
 
-class LInnerAllocatedObject: public LTemplateInstruction<1, 1, 0> {
+class LInnerAllocatedObject V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LInnerAllocatedObject(LOperand* base_object) {
     inputs_[0] = base_object;
@@ -1683,28 +1702,28 @@ class LInnerAllocatedObject: public LTemplateInstruction<1, 1, 0> {
   LOperand* base_object() { return inputs_[0]; }
   int offset() { return hydrogen()->offset(); }
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
   DECLARE_CONCRETE_INSTRUCTION(InnerAllocatedObject, "sub-allocated-object")
   DECLARE_HYDROGEN_ACCESSOR(InnerAllocatedObject)
 };
 
 
-class LThisFunction: public LTemplateInstruction<1, 0, 0> {
+class LThisFunction V8_FINAL : public LTemplateInstruction<1, 0, 0> {
  public:
   DECLARE_CONCRETE_INSTRUCTION(ThisFunction, "this-function")
   DECLARE_HYDROGEN_ACCESSOR(ThisFunction)
 };
 
 
-class LContext: public LTemplateInstruction<1, 0, 0> {
+class LContext V8_FINAL : public LTemplateInstruction<1, 0, 0> {
  public:
   DECLARE_CONCRETE_INSTRUCTION(Context, "context")
   DECLARE_HYDROGEN_ACCESSOR(Context)
 };
 
 
-class LOuterContext: public LTemplateInstruction<1, 1, 0> {
+class LOuterContext V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LOuterContext(LOperand* context) {
     inputs_[0] = context;
@@ -1716,20 +1735,20 @@ class LOuterContext: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LDeclareGlobals: public LTemplateInstruction<0, 0, 0> {
+class LDeclareGlobals V8_FINAL : public LTemplateInstruction<0, 0, 0> {
  public:
   DECLARE_CONCRETE_INSTRUCTION(DeclareGlobals, "declare-globals")
   DECLARE_HYDROGEN_ACCESSOR(DeclareGlobals)
 };
 
 
-class LGlobalObject: public LTemplateInstruction<1, 0, 0> {
+class LGlobalObject V8_FINAL : public LTemplateInstruction<1, 0, 0> {
  public:
   DECLARE_CONCRETE_INSTRUCTION(GlobalObject, "global-object")
 };
 
 
-class LGlobalReceiver: public LTemplateInstruction<1, 1, 0> {
+class LGlobalReceiver V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LGlobalReceiver(LOperand* global_object) {
     inputs_[0] = global_object;
@@ -1741,7 +1760,7 @@ class LGlobalReceiver: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LCallConstantFunction: public LTemplateInstruction<1, 0, 0> {
+class LCallConstantFunction V8_FINAL : public LTemplateInstruction<1, 0, 0> {
  public:
   DECLARE_CONCRETE_INSTRUCTION(CallConstantFunction, "call-constant-function")
   DECLARE_HYDROGEN_ACCESSOR(CallConstantFunction)
@@ -1753,7 +1772,7 @@ class LCallConstantFunction: public LTemplateInstruction<1, 0, 0> {
 };
 
 
-class LInvokeFunction: public LTemplateInstruction<1, 1, 0> {
+class LInvokeFunction V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LInvokeFunction(LOperand* function) {
     inputs_[0] = function;
@@ -1764,13 +1783,13 @@ class LInvokeFunction: public LTemplateInstruction<1, 1, 0> {
   DECLARE_CONCRETE_INSTRUCTION(InvokeFunction, "invoke-function")
   DECLARE_HYDROGEN_ACCESSOR(InvokeFunction)
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
   int arity() const { return hydrogen()->argument_count() - 1; }
 };
 
 
-class LCallKeyed: public LTemplateInstruction<1, 1, 0> {
+class LCallKeyed V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LCallKeyed(LOperand* key) {
     inputs_[0] = key;
@@ -1781,25 +1800,25 @@ class LCallKeyed: public LTemplateInstruction<1, 1, 0> {
 
   LOperand* key() { return inputs_[0]; }
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
   int arity() const { return hydrogen()->argument_count() - 1; }
 };
 
 
-class LCallNamed: public LTemplateInstruction<1, 0, 0> {
+class LCallNamed V8_FINAL : public LTemplateInstruction<1, 0, 0> {
  public:
   DECLARE_CONCRETE_INSTRUCTION(CallNamed, "call-named")
   DECLARE_HYDROGEN_ACCESSOR(CallNamed)
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
   Handle<String> name() const { return hydrogen()->name(); }
   int arity() const { return hydrogen()->argument_count() - 1; }
 };
 
 
-class LCallFunction: public LTemplateInstruction<1, 1, 0> {
+class LCallFunction V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LCallFunction(LOperand* function) {
     inputs_[0] = function;
@@ -1813,30 +1832,30 @@ class LCallFunction: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LCallGlobal: public LTemplateInstruction<1, 0, 0> {
+class LCallGlobal V8_FINAL : public LTemplateInstruction<1, 0, 0> {
  public:
   DECLARE_CONCRETE_INSTRUCTION(CallGlobal, "call-global")
   DECLARE_HYDROGEN_ACCESSOR(CallGlobal)
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
   Handle<String> name() const {return hydrogen()->name(); }
   int arity() const { return hydrogen()->argument_count() - 1; }
 };
 
 
-class LCallKnownGlobal: public LTemplateInstruction<1, 0, 0> {
+class LCallKnownGlobal V8_FINAL : public LTemplateInstruction<1, 0, 0> {
  public:
   DECLARE_CONCRETE_INSTRUCTION(CallKnownGlobal, "call-known-global")
   DECLARE_HYDROGEN_ACCESSOR(CallKnownGlobal)
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
   int arity() const { return hydrogen()->argument_count() - 1;  }
 };
 
 
-class LCallNew: public LTemplateInstruction<1, 1, 0> {
+class LCallNew V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LCallNew(LOperand* constructor) {
     inputs_[0] = constructor;
@@ -1847,13 +1866,13 @@ class LCallNew: public LTemplateInstruction<1, 1, 0> {
   DECLARE_CONCRETE_INSTRUCTION(CallNew, "call-new")
   DECLARE_HYDROGEN_ACCESSOR(CallNew)
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
   int arity() const { return hydrogen()->argument_count() - 1; }
 };
 
 
-class LCallNewArray: public LTemplateInstruction<1, 1, 0> {
+class LCallNewArray V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LCallNewArray(LOperand* constructor) {
     inputs_[0] = constructor;
@@ -1864,13 +1883,13 @@ class LCallNewArray: public LTemplateInstruction<1, 1, 0> {
   DECLARE_CONCRETE_INSTRUCTION(CallNewArray, "call-new-array")
   DECLARE_HYDROGEN_ACCESSOR(CallNewArray)
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
   int arity() const { return hydrogen()->argument_count() - 1; }
 };
 
 
-class LCallRuntime: public LTemplateInstruction<1, 0, 0> {
+class LCallRuntime V8_FINAL : public LTemplateInstruction<1, 0, 0> {
  public:
   DECLARE_CONCRETE_INSTRUCTION(CallRuntime, "call-runtime")
   DECLARE_HYDROGEN_ACCESSOR(CallRuntime)
@@ -1880,7 +1899,7 @@ class LCallRuntime: public LTemplateInstruction<1, 0, 0> {
 };
 
 
-class LInteger32ToDouble: public LTemplateInstruction<1, 1, 0> {
+class LInteger32ToDouble V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LInteger32ToDouble(LOperand* value) {
     inputs_[0] = value;
@@ -1892,7 +1911,7 @@ class LInteger32ToDouble: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LInteger32ToSmi: public LTemplateInstruction<1, 1, 0> {
+class LInteger32ToSmi V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LInteger32ToSmi(LOperand* value) {
     inputs_[0] = value;
@@ -1905,7 +1924,7 @@ class LInteger32ToSmi: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LUint32ToDouble: public LTemplateInstruction<1, 1, 1> {
+class LUint32ToDouble V8_FINAL : public LTemplateInstruction<1, 1, 1> {
  public:
   explicit LUint32ToDouble(LOperand* value, LOperand* temp) {
     inputs_[0] = value;
@@ -1919,7 +1938,7 @@ class LUint32ToDouble: public LTemplateInstruction<1, 1, 1> {
 };
 
 
-class LNumberTagI: public LTemplateInstruction<1, 1, 0> {
+class LNumberTagI V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LNumberTagI(LOperand* value) {
     inputs_[0] = value;
@@ -1931,7 +1950,7 @@ class LNumberTagI: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LNumberTagU: public LTemplateInstruction<1, 1, 1> {
+class LNumberTagU V8_FINAL : public LTemplateInstruction<1, 1, 1> {
  public:
   explicit LNumberTagU(LOperand* value, LOperand* temp) {
     inputs_[0] = value;
@@ -1945,7 +1964,7 @@ class LNumberTagU: public LTemplateInstruction<1, 1, 1> {
 };
 
 
-class LNumberTagD: public LTemplateInstruction<1, 1, 1> {
+class LNumberTagD V8_FINAL : public LTemplateInstruction<1, 1, 1> {
  public:
   explicit LNumberTagD(LOperand* value, LOperand* temp) {
     inputs_[0] = value;
@@ -1961,7 +1980,7 @@ class LNumberTagD: public LTemplateInstruction<1, 1, 1> {
 
 
 // Sometimes truncating conversion from a tagged value to an int32.
-class LDoubleToI: public LTemplateInstruction<1, 1, 0> {
+class LDoubleToI V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LDoubleToI(LOperand* value) {
     inputs_[0] = value;
@@ -1976,7 +1995,7 @@ class LDoubleToI: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LDoubleToSmi: public LTemplateInstruction<1, 1, 0> {
+class LDoubleToSmi V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LDoubleToSmi(LOperand* value) {
     inputs_[0] = value;
@@ -1990,7 +2009,7 @@ class LDoubleToSmi: public LTemplateInstruction<1, 1, 0> {
 
 
 // Truncating conversion from a tagged value to an int32.
-class LTaggedToI: public LTemplateInstruction<1, 1, 1> {
+class LTaggedToI V8_FINAL : public LTemplateInstruction<1, 1, 1> {
  public:
   LTaggedToI(LOperand* value, LOperand* temp) {
     inputs_[0] = value;
@@ -2007,7 +2026,7 @@ class LTaggedToI: public LTemplateInstruction<1, 1, 1> {
 };
 
 
-class LSmiTag: public LTemplateInstruction<1, 1, 0> {
+class LSmiTag V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LSmiTag(LOperand* value) {
     inputs_[0] = value;
@@ -2019,7 +2038,7 @@ class LSmiTag: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LNumberUntagD: public LTemplateInstruction<1, 1, 0> {
+class LNumberUntagD V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LNumberUntagD(LOperand* value) {
     inputs_[0] = value;
@@ -2032,7 +2051,7 @@ class LNumberUntagD: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LSmiUntag: public LTemplateInstruction<1, 1, 0> {
+class LSmiUntag V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   LSmiUntag(LOperand* value, bool needs_check)
       : needs_check_(needs_check) {
@@ -2049,7 +2068,7 @@ class LSmiUntag: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LStoreNamedField: public LTemplateInstruction<0, 2, 1> {
+class LStoreNamedField V8_FINAL : public LTemplateInstruction<0, 2, 1> {
  public:
   LStoreNamedField(LOperand* object, LOperand* value, LOperand* temp) {
     inputs_[0] = object;
@@ -2064,7 +2083,7 @@ class LStoreNamedField: public LTemplateInstruction<0, 2, 1> {
   DECLARE_CONCRETE_INSTRUCTION(StoreNamedField, "store-named-field")
   DECLARE_HYDROGEN_ACCESSOR(StoreNamedField)
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
   Handle<Map> transition() const { return hydrogen()->transition_map(); }
   Representation representation() const {
@@ -2073,7 +2092,7 @@ class LStoreNamedField: public LTemplateInstruction<0, 2, 1> {
 };
 
 
-class LStoreNamedGeneric: public LTemplateInstruction<0, 2, 0> {
+class LStoreNamedGeneric V8_FINAL : public LTemplateInstruction<0, 2, 0> {
  public:
   LStoreNamedGeneric(LOperand* object, LOperand* value) {
     inputs_[0] = object;
@@ -2086,14 +2105,14 @@ class LStoreNamedGeneric: public LTemplateInstruction<0, 2, 0> {
   DECLARE_CONCRETE_INSTRUCTION(StoreNamedGeneric, "store-named-generic")
   DECLARE_HYDROGEN_ACCESSOR(StoreNamedGeneric)
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
   Handle<Object> name() const { return hydrogen()->name(); }
   StrictModeFlag strict_mode_flag() { return hydrogen()->strict_mode_flag(); }
 };
 
 
-class LStoreKeyed: public LTemplateInstruction<0, 3, 0> {
+class LStoreKeyed V8_FINAL : public LTemplateInstruction<0, 3, 0> {
  public:
   LStoreKeyed(LOperand* object, LOperand* key, LOperand* value) {
     inputs_[0] = object;
@@ -2110,13 +2129,13 @@ class LStoreKeyed: public LTemplateInstruction<0, 3, 0> {
   DECLARE_CONCRETE_INSTRUCTION(StoreKeyed, "store-keyed")
   DECLARE_HYDROGEN_ACCESSOR(StoreKeyed)
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
   bool NeedsCanonicalization() { return hydrogen()->NeedsCanonicalization(); }
   uint32_t additional_index() const { return hydrogen()->index_offset(); }
 };
 
 
-class LStoreKeyedGeneric: public LTemplateInstruction<0, 3, 0> {
+class LStoreKeyedGeneric V8_FINAL : public LTemplateInstruction<0, 3, 0> {
  public:
   LStoreKeyedGeneric(LOperand* object, LOperand* key, LOperand* value) {
     inputs_[0] = object;
@@ -2131,13 +2150,13 @@ class LStoreKeyedGeneric: public LTemplateInstruction<0, 3, 0> {
   DECLARE_CONCRETE_INSTRUCTION(StoreKeyedGeneric, "store-keyed-generic")
   DECLARE_HYDROGEN_ACCESSOR(StoreKeyedGeneric)
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
   StrictModeFlag strict_mode_flag() { return hydrogen()->strict_mode_flag(); }
 };
 
 
-class LTransitionElementsKind: public LTemplateInstruction<0, 1, 2> {
+class LTransitionElementsKind V8_FINAL : public LTemplateInstruction<0, 1, 2> {
  public:
   LTransitionElementsKind(LOperand* object,
                           LOperand* new_map_temp,
@@ -2155,7 +2174,7 @@ class LTransitionElementsKind: public LTemplateInstruction<0, 1, 2> {
                                "transition-elements-kind")
   DECLARE_HYDROGEN_ACCESSOR(TransitionElementsKind)
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
   Handle<Map> original_map() { return hydrogen()->original_map(); }
   Handle<Map> transitioned_map() { return hydrogen()->transitioned_map(); }
@@ -2164,7 +2183,7 @@ class LTransitionElementsKind: public LTemplateInstruction<0, 1, 2> {
 };
 
 
-class LTrapAllocationMemento : public LTemplateInstruction<0, 1, 1> {
+class LTrapAllocationMemento V8_FINAL : public LTemplateInstruction<0, 1, 1> {
  public:
   LTrapAllocationMemento(LOperand* object,
                          LOperand* temp) {
@@ -2180,7 +2199,7 @@ class LTrapAllocationMemento : public LTemplateInstruction<0, 1, 1> {
 };
 
 
-class LStringAdd: public LTemplateInstruction<1, 2, 0> {
+class LStringAdd V8_FINAL : public LTemplateInstruction<1, 2, 0> {
  public:
   LStringAdd(LOperand* left, LOperand* right) {
     inputs_[0] = left;
@@ -2195,7 +2214,7 @@ class LStringAdd: public LTemplateInstruction<1, 2, 0> {
 };
 
 
-class LStringCharCodeAt: public LTemplateInstruction<1, 2, 0> {
+class LStringCharCodeAt V8_FINAL : public LTemplateInstruction<1, 2, 0> {
  public:
   LStringCharCodeAt(LOperand* string, LOperand* index) {
     inputs_[0] = string;
@@ -2210,7 +2229,7 @@ class LStringCharCodeAt: public LTemplateInstruction<1, 2, 0> {
 };
 
 
-class LStringCharFromCode: public LTemplateInstruction<1, 1, 0> {
+class LStringCharFromCode V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LStringCharFromCode(LOperand* char_code) {
     inputs_[0] = char_code;
@@ -2223,7 +2242,7 @@ class LStringCharFromCode: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LCheckFunction: public LTemplateInstruction<0, 1, 0> {
+class LCheckFunction V8_FINAL : public LTemplateInstruction<0, 1, 0> {
  public:
   explicit LCheckFunction(LOperand* value) {
     inputs_[0] = value;
@@ -2236,7 +2255,7 @@ class LCheckFunction: public LTemplateInstruction<0, 1, 0> {
 };
 
 
-class LCheckInstanceType: public LTemplateInstruction<0, 1, 0> {
+class LCheckInstanceType V8_FINAL : public LTemplateInstruction<0, 1, 0> {
  public:
   explicit LCheckInstanceType(LOperand* value) {
     inputs_[0] = value;
@@ -2249,7 +2268,7 @@ class LCheckInstanceType: public LTemplateInstruction<0, 1, 0> {
 };
 
 
-class LCheckMaps: public LTemplateInstruction<0, 1, 0> {
+class LCheckMaps V8_FINAL : public LTemplateInstruction<0, 1, 0> {
  public:
   explicit LCheckMaps(LOperand* value) {
     inputs_[0] = value;
@@ -2262,7 +2281,7 @@ class LCheckMaps: public LTemplateInstruction<0, 1, 0> {
 };
 
 
-class LCheckSmi: public LTemplateInstruction<1, 1, 0> {
+class LCheckSmi V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LCheckSmi(LOperand* value) {
     inputs_[0] = value;
@@ -2274,7 +2293,7 @@ class LCheckSmi: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LClampDToUint8: public LTemplateInstruction<1, 1, 0> {
+class LClampDToUint8 V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LClampDToUint8(LOperand* unclamped) {
     inputs_[0] = unclamped;
@@ -2286,7 +2305,7 @@ class LClampDToUint8: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LClampIToUint8: public LTemplateInstruction<1, 1, 0> {
+class LClampIToUint8 V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LClampIToUint8(LOperand* unclamped) {
     inputs_[0] = unclamped;
@@ -2298,7 +2317,7 @@ class LClampIToUint8: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LClampTToUint8: public LTemplateInstruction<1, 1, 1> {
+class LClampTToUint8 V8_FINAL : public LTemplateInstruction<1, 1, 1> {
  public:
   LClampTToUint8(LOperand* unclamped,
                  LOperand* temp_xmm) {
@@ -2313,7 +2332,7 @@ class LClampTToUint8: public LTemplateInstruction<1, 1, 1> {
 };
 
 
-class LCheckNonSmi: public LTemplateInstruction<0, 1, 0> {
+class LCheckNonSmi V8_FINAL : public LTemplateInstruction<0, 1, 0> {
  public:
   explicit LCheckNonSmi(LOperand* value) {
     inputs_[0] = value;
@@ -2326,7 +2345,7 @@ class LCheckNonSmi: public LTemplateInstruction<0, 1, 0> {
 };
 
 
-class LAllocate: public LTemplateInstruction<1, 1, 1> {
+class LAllocate V8_FINAL : public LTemplateInstruction<1, 1, 1> {
  public:
   LAllocate(LOperand* size, LOperand* temp) {
     inputs_[0] = size;
@@ -2341,21 +2360,21 @@ class LAllocate: public LTemplateInstruction<1, 1, 1> {
 };
 
 
-class LRegExpLiteral: public LTemplateInstruction<1, 0, 0> {
+class LRegExpLiteral V8_FINAL : public LTemplateInstruction<1, 0, 0> {
  public:
   DECLARE_CONCRETE_INSTRUCTION(RegExpLiteral, "regexp-literal")
   DECLARE_HYDROGEN_ACCESSOR(RegExpLiteral)
 };
 
 
-class LFunctionLiteral: public LTemplateInstruction<1, 0, 0> {
+class LFunctionLiteral V8_FINAL : public LTemplateInstruction<1, 0, 0> {
  public:
   DECLARE_CONCRETE_INSTRUCTION(FunctionLiteral, "function-literal")
   DECLARE_HYDROGEN_ACCESSOR(FunctionLiteral)
 };
 
 
-class LToFastProperties: public LTemplateInstruction<1, 1, 0> {
+class LToFastProperties V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LToFastProperties(LOperand* value) {
     inputs_[0] = value;
@@ -2368,7 +2387,7 @@ class LToFastProperties: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LTypeof: public LTemplateInstruction<1, 1, 0> {
+class LTypeof V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LTypeof(LOperand* value) {
     inputs_[0] = value;
@@ -2380,7 +2399,7 @@ class LTypeof: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LTypeofIsAndBranch: public LControlInstruction<1, 0> {
+class LTypeofIsAndBranch V8_FINAL : public LControlInstruction<1, 0> {
  public:
   explicit LTypeofIsAndBranch(LOperand* value) {
     inputs_[0] = value;
@@ -2393,11 +2412,11 @@ class LTypeofIsAndBranch: public LControlInstruction<1, 0> {
 
   Handle<String> type_literal() { return hydrogen()->type_literal(); }
 
-  virtual void PrintDataTo(StringStream* stream);
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 };
 
 
-class LIsConstructCallAndBranch: public LControlInstruction<0, 1> {
+class LIsConstructCallAndBranch V8_FINAL : public LControlInstruction<0, 1> {
  public:
   explicit LIsConstructCallAndBranch(LOperand* temp) {
     temps_[0] = temp;
@@ -2411,16 +2430,18 @@ class LIsConstructCallAndBranch: public LControlInstruction<0, 1> {
 };
 
 
-class LOsrEntry: public LTemplateInstruction<0, 0, 0> {
+class LOsrEntry V8_FINAL : public LTemplateInstruction<0, 0, 0> {
  public:
   LOsrEntry() {}
 
-  virtual bool HasInterestingComment(LCodeGen* gen) const { return false; }
+  virtual bool HasInterestingComment(LCodeGen* gen) const V8_OVERRIDE {
+    return false;
+  }
   DECLARE_CONCRETE_INSTRUCTION(OsrEntry, "osr-entry")
 };
 
 
-class LStackCheck: public LTemplateInstruction<0, 0, 0> {
+class LStackCheck V8_FINAL : public LTemplateInstruction<0, 0, 0> {
  public:
   DECLARE_CONCRETE_INSTRUCTION(StackCheck, "stack-check")
   DECLARE_HYDROGEN_ACCESSOR(StackCheck)
@@ -2432,7 +2453,7 @@ class LStackCheck: public LTemplateInstruction<0, 0, 0> {
 };
 
 
-class LForInPrepareMap: public LTemplateInstruction<1, 1, 0> {
+class LForInPrepareMap V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LForInPrepareMap(LOperand* object) {
     inputs_[0] = object;
@@ -2444,7 +2465,7 @@ class LForInPrepareMap: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LForInCacheArray: public LTemplateInstruction<1, 1, 0> {
+class LForInCacheArray V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LForInCacheArray(LOperand* map) {
     inputs_[0] = map;
@@ -2460,7 +2481,7 @@ class LForInCacheArray: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LCheckMapValue: public LTemplateInstruction<0, 2, 0> {
+class LCheckMapValue V8_FINAL : public LTemplateInstruction<0, 2, 0> {
  public:
   LCheckMapValue(LOperand* value, LOperand* map) {
     inputs_[0] = value;
@@ -2474,7 +2495,7 @@ class LCheckMapValue: public LTemplateInstruction<0, 2, 0> {
 };
 
 
-class LLoadFieldByIndex: public LTemplateInstruction<1, 2, 0> {
+class LLoadFieldByIndex V8_FINAL : public LTemplateInstruction<1, 2, 0> {
  public:
   LLoadFieldByIndex(LOperand* object, LOperand* index) {
     inputs_[0] = object;
@@ -2489,7 +2510,7 @@ class LLoadFieldByIndex: public LTemplateInstruction<1, 2, 0> {
 
 
 class LChunkBuilder;
-class LPlatformChunk: public LChunk {
+class LPlatformChunk V8_FINAL : public LChunk {
  public:
   LPlatformChunk(CompilationInfo* info, HGraph* graph)
       : LChunk(info, graph) { }
@@ -2499,7 +2520,7 @@ class LPlatformChunk: public LChunk {
 };
 
 
-class LChunkBuilder BASE_EMBEDDED {
+class LChunkBuilder V8_FINAL BASE_EMBEDDED {
  public:
   LChunkBuilder(CompilationInfo* info, HGraph* graph, LAllocator* allocator)
       : chunk_(NULL),