[Isolates] Merge r 6300:6500 from bleeding_edge to isolates.

src/hydrogen-instructions.h

-// Copyright 2010 the V8 project authors. All rights reserved.
+// Copyright 2011 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
 //       with the distribution.
@@ skipping 27 matching lines @@
 // Forward declarations.
 class HBasicBlock;
 class HEnvironment;
 class HInstruction;
 class HLoopInformation;
 class HValue;
 class LInstruction;
 class LChunkBuilder;
 
 
-// Type hierarchy:
-//
-// HValue
-//   HInstruction
-//     HAccessArgumentsAt
-//     HApplyArguments
-//     HArgumentsElements
-//     HArgumentsLength
-//     HArgumentsObject
-//     HBinaryOperation
-//       HArithmeticBinaryOperation
-//         HAdd
-//         HDiv
-//         HMod
-//         HMul
-//         HSub
-//       HBitwiseBinaryOperation
-//         HBitAnd
-//         HBitOr
-//         HBitXor
-//         HSar
-//         HShl
-//         HShr
-//       HBoundsCheck
-//       HCompare
-//       HCompareJSObjectEq
-//       HInstanceOf
-//       HInstanceOfKnownGlobal
-//       HLoadKeyed
-//         HLoadKeyedFastElement
-//         HLoadKeyedGeneric
-//       HPower
-//       HStoreNamed
-//         HStoreNamedField
-//         HStoreNamedGeneric
-//     HBlockEntry
-//     HCall
-//       HCallConstantFunction
-//       HCallFunction
-//       HCallGlobal
-//       HCallKeyed
-//       HCallKnownGlobal
-//       HCallNamed
-//       HCallNew
-//       HCallRuntime
-//     HCallStub
-//     HCheckPrototypeMaps
-//     HConstant
-//     HControlInstruction
-//       HDeoptimize
-//       HGoto
-//       HUnaryControlInstruction
-//         HBranch
-//         HCompareMapAndBranch
-//         HReturn
-//         HThrow
-//     HEnterInlined
-//     HFunctionLiteral
-//     HGlobalObject
-//     HGlobalReceiver
-//     HLeaveInlined
-//     HLoadGlobal
-//     HMaterializedLiteral
-//       HArrayLiteral
-//       HObjectLiteral
-//       HRegExpLiteral
-//     HOsrEntry
-//     HParameter
-//     HSimulate
-//     HStackCheck
-//     HStoreKeyed
-//       HStoreKeyedFastElement
-//       HStoreKeyedGeneric
-//     HUnaryOperation
-//       HBitNot
-//       HChange
-//       HCheckFunction
-//       HCheckInstanceType
-//       HCheckMap
-//       HCheckNonSmi
-//       HCheckSmi
-//       HDeleteProperty
-//       HFixedArrayLength
-//       HJSArrayLength
-//       HLoadElements
-//         HTypeofIs
-//       HLoadNamedField
-//       HLoadNamedGeneric
-//       HLoadFunctionPrototype
-//       HPushArgument
-//       HTypeof
-//       HUnaryMathOperation
-//       HUnaryPredicate
-//         HClassOfTest
-//         HHasCachedArrayIndex
-//         HHasInstanceType
-//         HIsNull
-//         HIsObject
-//         HIsSmi
-//       HValueOf
-//     HUnknownOSRValue
-//   HPhi
-
 #define HYDROGEN_ALL_INSTRUCTION_LIST(V)       \
   V(ArithmeticBinaryOperation)                 \
   V(BinaryOperation)                           \
   V(BitwiseBinaryOperation)                    \
   V(Call)                                      \
   V(ControlInstruction)                        \
   V(Instruction)                               \
   V(LoadKeyed)                                 \
   V(MaterializedLiteral)                       \
   V(Phi)                                       \
@@ skipping 11 matching lines @@
   V(ArgumentsElements)                         \
   V(ArgumentsLength)                           \
   V(ArgumentsObject)                           \
   V(ArrayLiteral)                              \
   V(BitAnd)                                    \
   V(BitNot)                                    \
   V(BitOr)                                     \
   V(BitXor)                                    \
   V(BlockEntry)                                \
   V(BoundsCheck)                               \
-  V(Branch)                                    \
   V(CallConstantFunction)                      \
   V(CallFunction)                              \
   V(CallGlobal)                                \
   V(CallKeyed)                                 \
   V(CallKnownGlobal)                           \
   V(CallNamed)                                 \
   V(CallNew)                                   \
   V(CallRuntime)                               \
   V(CallStub)                                  \
   V(Change)                                    \
   V(CheckFunction)                             \
   V(CheckInstanceType)                         \
   V(CheckMap)                                  \
   V(CheckNonSmi)                               \
   V(CheckPrototypeMaps)                        \
   V(CheckSmi)                                  \
   V(Compare)                                   \
   V(CompareJSObjectEq)                         \
-  V(CompareMapAndBranch)                       \
+  V(CompareMap)                                \
   V(Constant)                                  \
   V(DeleteProperty)                            \
   V(Deoptimize)                                \
   V(Div)                                       \
   V(EnterInlined)                              \
   V(FixedArrayLength)                          \
   V(FunctionLiteral)                           \
   V(GlobalObject)                              \
   V(GlobalReceiver)                            \
   V(Goto)                                      \
   V(InstanceOf)                                \
   V(InstanceOfKnownGlobal)                     \
   V(IsNull)                                    \
   V(IsObject)                                  \
   V(IsSmi)                                     \
   V(HasInstanceType)                           \
   V(HasCachedArrayIndex)                       \
   V(JSArrayLength)                             \
   V(ClassOfTest)                               \
   V(LeaveInlined)                              \
+  V(LoadContextSlot)                           \
   V(LoadElements)                              \
+  V(LoadFunctionPrototype)                     \
   V(LoadGlobal)                                \
   V(LoadKeyedFastElement)                      \
   V(LoadKeyedGeneric)                          \
   V(LoadNamedField)                            \
   V(LoadNamedGeneric)                          \
-  V(LoadFunctionPrototype)                     \
   V(Mod)                                       \
   V(Mul)                                       \
   V(ObjectLiteral)                             \
   V(OsrEntry)                                  \
   V(Parameter)                                 \
   V(Power)                                     \
   V(PushArgument)                              \
   V(RegExpLiteral)                             \
   V(Return)                                    \
   V(Sar)                                       \
   V(Shl)                                       \
   V(Shr)                                       \
   V(Simulate)                                  \
   V(StackCheck)                                \
   V(StoreGlobal)                               \
   V(StoreKeyedFastElement)                     \
   V(StoreKeyedGeneric)                         \
   V(StoreNamedField)                           \
   V(StoreNamedGeneric)                         \
+  V(StringCharCodeAt)                          \
+  V(StringLength)                              \
   V(Sub)                                       \
+  V(Test)                                      \
   V(Throw)                                     \
   V(Typeof)                                    \
   V(TypeofIs)                                  \
   V(UnaryMathOperation)                        \
   V(UnknownOSRValue)                           \
   V(ValueOf)
 
 #define GVN_FLAG_LIST(V)                       \
   V(Calls)                                     \
   V(InobjectFields)                            \
   V(BackingStoreFields)                        \
   V(ArrayElements)                             \
   V(GlobalVars)                                \
   V(Maps)                                      \
   V(ArrayLengths)                              \
-  V(FunctionPrototypes)                        \
   V(OsrEntries)
 
 #define DECLARE_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);       \
   }                                                 \
   Opcode opcode() const { return HValue::k##type; }
 
@@ skipping 284 matching lines @@
   }
 
   static int DependsFlagsMask() {
     return ConvertChangesToDependsFlags(ChangesFlagsMask());
   }
 
   static int ConvertChangesToDependsFlags(int flags) {
     return flags << kChangesToDependsFlagsLeftShift;
   }
 
-  // A flag mask to mark an instruction as having arbitrary side effects.
-  static int AllSideEffects() {
-    return ChangesFlagsMask() & ~(1 << kChangesOsrEntries);
-  }
-
   static HValue* cast(HValue* value) { return value; }
 
   enum Opcode {
     // Declare a unique enum value for each hydrogen instruction.
   #define DECLARE_DO(type) k##type,
     HYDROGEN_ALL_INSTRUCTION_LIST(DECLARE_DO)
   #undef DECLARE_DO
     kMaxInstructionClass
   };
 
@@ skipping 38 matching lines @@
   // If the operation also exists in a form that takes int32 and outputs int32
   // then the operation should return its input value so that we can propagate
   // back.  There are two operations that need to propagate back to more than
   // one input.  They are phi and binary add.  They always return NULL and
   // expect the caller to take care of things.
   virtual HValue* EnsureAndPropagateNotMinusZero(BitVector* visited) {
     visited->Add(id());
     return NULL;
   }
 
-  bool HasSideEffects() const {
-    return (flags_ & AllSideEffects()) != 0;
-  }
   bool IsDefinedAfter(HBasicBlock* other) const;
 
   // Operands.
   virtual int OperandCount() const { return 0; }
   virtual HValue* OperandAt(int index) const {
     UNREACHABLE();
     return NULL;
   }
   void SetOperandAt(int index, HValue* value);
 
   int LookupOperandIndex(int occurrence_index, HValue* op) const;
   bool UsesMultipleTimes(HValue* op) const;
 
   void ReplaceAndDelete(HValue* other);
   void ReplaceValue(HValue* other);
   void ReplaceAtUse(HValue* use, HValue* other);
   void ReplaceFirstAtUse(HValue* use, HValue* other, Representation r);
   bool HasNoUses() const { return uses_.is_empty(); }
   void ClearOperands();
   void Delete();
 
   int flags() const { return flags_; }
-  void SetFlagMask(int mask) { flags_ |= mask; }
-  void SetFlag(Flag f) { SetFlagMask(1 << f); }
-  void ClearFlagMask(int mask) { flags_ &= ~mask; }
-  void ClearFlag(Flag f) { ClearFlagMask(1 << f); }
-  bool CheckFlag(Flag f) const { return CheckFlagMask(1 << f); }
-  bool CheckFlagMask(int mask) const { return (flags_ & mask) != 0; }
+  void SetFlag(Flag f) { flags_ |= (1 << f); }
+  void ClearFlag(Flag f) { flags_ &= ~(1 << f); }
+  bool CheckFlag(Flag f) const { return (flags_ & (1 << f)) != 0; }
+
+  void SetAllSideEffects() { flags_ |= AllSideEffects(); }
+  void ClearAllSideEffects() { flags_ &= ~AllSideEffects(); }
+  bool HasSideEffects() const { return (flags_ & AllSideEffects()) != 0; }
 
   Range* range() const { return range_; }
   bool HasRange() const { return range_ != NULL; }
   void AddNewRange(Range* r);
   void RemoveLastAddedRange();
   void ComputeInitialRange();
 
   // Representation helpers.
   virtual Representation RequiredInputRepresentation(int index) const {
     return Representation::None();
@@ skipping 27 matching lines @@
   // Updated the inferred type of this instruction and returns true if
   // it has changed.
   bool UpdateInferredType();
 
   virtual HType CalculateInferredType() const;
 
   // Helper for type conversions used by normal and phi instructions.
   void InsertInputConversion(HInstruction* previous, int index, HType type);
 
 #ifdef DEBUG
-  virtual void Verify() const = 0;
+  virtual void Verify() = 0;
 #endif
 
  protected:
-  virtual bool DataEquals(HValue* other) const { return true; }
+  // This function must be overridden for instructions with flag kUseGVN, to
+  // compare the non-Operand parts of the instruction.
+  virtual bool DataEquals(HValue* other) const {
+    UNREACHABLE();
+    return false;
+  }
   virtual void RepresentationChanged(Representation to) { }
   virtual Range* InferRange();
   virtual void DeleteFromGraph() = 0;
   virtual void InternalSetOperandAt(int index, HValue* value) { UNREACHABLE(); }
   void clear_block() {
     ASSERT(block_ != NULL);
     block_ = NULL;
   }
 
   void set_representation(Representation r) {
     // Representation is set-once.
     ASSERT(representation_.IsNone() && !r.IsNone());
     representation_ = r;
   }
 
  private:
+  // A flag mask to mark an instruction as having arbitrary side effects.
+  static int AllSideEffects() {
+    return ChangesFlagsMask() & ~(1 << kChangesOsrEntries);
+  }
+
   void InternalReplaceAtUse(HValue* use, HValue* other);
   void RegisterUse(int index, HValue* new_value);
 
   HBasicBlock* block_;
 
   // The id of this instruction in the hydrogen graph, assigned when first
   // added to the graph. Reflects creation order.
   int id_;
 
   Representation representation_;
@@ skipping 19 matching lines @@
   void InsertBefore(HInstruction* next);
   void InsertAfter(HInstruction* previous);
 
   int position() const { return position_; }
   bool has_position() const { return position_ != RelocInfo::kNoPosition; }
   void set_position(int position) { position_ = position; }
 
   virtual LInstruction* CompileToLithium(LChunkBuilder* builder) = 0;
 
 #ifdef DEBUG
-  virtual void Verify() const;
+  virtual void Verify();
 #endif
 
+  // Returns whether this is some kind of deoptimizing check
+  // instruction.
+  virtual bool IsCheckInstruction() const { return false; }
+
   DECLARE_INSTRUCTION(Instruction)
 
  protected:
   HInstruction()
       : next_(NULL),
         previous_(NULL),
         position_(RelocInfo::kNoPosition) {
     SetFlag(kDependsOnOsrEntries);
   }
 
@@ skipping 14 matching lines @@
 
 
 class HBlockEntry: public HInstruction {
  public:
   DECLARE_CONCRETE_INSTRUCTION(BlockEntry, "block_entry")
 };
 
 
 class HControlInstruction: public HInstruction {
  public:
-  virtual HBasicBlock* FirstSuccessor() const { return NULL; }
-  virtual HBasicBlock* SecondSuccessor() const { return NULL; }
+  HControlInstruction(HBasicBlock* first, HBasicBlock* second)
+      : first_successor_(first), second_successor_(second) {
+  }
+
+  HBasicBlock* FirstSuccessor() const { return first_successor_; }
+  HBasicBlock* SecondSuccessor() const { return second_successor_; }
+
+  virtual void PrintDataTo(StringStream* stream) const;
 
   DECLARE_INSTRUCTION(ControlInstruction)
+
+ private:
+  HBasicBlock* first_successor_;
+  HBasicBlock* second_successor_;
 };
 
 
 class HDeoptimize: public HControlInstruction {
  public:
+  HDeoptimize() : HControlInstruction(NULL, NULL) { }
+
   DECLARE_CONCRETE_INSTRUCTION(Deoptimize, "deoptimize")
 };
 
 
 class HGoto: public HControlInstruction {
  public:
-  explicit HGoto(HBasicBlock* destination)
-      : destination_(destination),
-        include_stack_check_(false) {}
+  explicit HGoto(HBasicBlock* target)
+      : HControlInstruction(target, NULL), include_stack_check_(false) {
+  }
 
-  virtual HBasicBlock* FirstSuccessor() const { return destination_; }
   void set_include_stack_check(bool include_stack_check) {
     include_stack_check_ = include_stack_check;
   }
   bool include_stack_check() const { return include_stack_check_; }
 
-  virtual void PrintDataTo(StringStream* stream) const;
-
   DECLARE_CONCRETE_INSTRUCTION(Goto, "goto")
 
  private:
-  HBasicBlock* destination_;
   bool include_stack_check_;
 };
 
 
 class HUnaryControlInstruction: public HControlInstruction {
  public:
-  explicit HUnaryControlInstruction(HValue* value) {
+  explicit HUnaryControlInstruction(HValue* value,
+                                    HBasicBlock* true_target,
+                                    HBasicBlock* false_target)
+      : HControlInstruction(true_target, false_target) {
     SetOperandAt(0, value);
   }
 
   virtual Representation RequiredInputRepresentation(int index) const {
     return Representation::Tagged();
   }
 
+  virtual void PrintDataTo(StringStream* stream) const;
+
   HValue* value() const { return OperandAt(0); }
   virtual int OperandCount() const { return 1; }
   virtual HValue* OperandAt(int index) const { return operands_[index]; }
 
   DECLARE_INSTRUCTION(UnaryControlInstruction)
 
  protected:
   virtual void InternalSetOperandAt(int index, HValue* value) {
     operands_[index] = value;
   }
 
  private:
   HOperandVector<1> operands_;
 };
 
 
-class HBranch: public HUnaryControlInstruction {
+class HTest: public HUnaryControlInstruction {
  public:
-  HBranch(HBasicBlock* true_destination,
-          HBasicBlock* false_destination,
-          HValue* boolean_value)
-      : HUnaryControlInstruction(boolean_value),
-        true_destination_(true_destination),
-        false_destination_(false_destination) {
-    ASSERT(true_destination != NULL && false_destination != NULL);
+  HTest(HValue* value, HBasicBlock* true_target, HBasicBlock* false_target)
+      : HUnaryControlInstruction(value, true_target, false_target) {
+    ASSERT(true_target != NULL && false_target != NULL);
   }
 
   virtual Representation RequiredInputRepresentation(int index) const {
     return Representation::None();
   }
 
-  virtual HBasicBlock* FirstSuccessor() const { return true_destination_; }
-  virtual HBasicBlock* SecondSuccessor() const { return false_destination_; }
-
-  virtual void PrintDataTo(StringStream* stream) const;
-
-  DECLARE_CONCRETE_INSTRUCTION(Branch, "branch")
-
- private:
-  HBasicBlock* true_destination_;
-  HBasicBlock* false_destination_;
+  DECLARE_CONCRETE_INSTRUCTION(Test, "test")
 };
 
 
-class HCompareMapAndBranch: public HUnaryControlInstruction {
+class HCompareMap: public HUnaryControlInstruction {
  public:
-  HCompareMapAndBranch(HValue* result,
-                       Handle<Map> map,
-                       HBasicBlock* true_destination,
-                       HBasicBlock* false_destination)
-      : HUnaryControlInstruction(result),
-        map_(map),
-        true_destination_(true_destination),
-        false_destination_(false_destination) {
-    ASSERT(true_destination != NULL);
-    ASSERT(false_destination != NULL);
+  HCompareMap(HValue* value,
+              Handle<Map> map,
+              HBasicBlock* true_target,
+              HBasicBlock* false_target)
+      : HUnaryControlInstruction(value, true_target, false_target),
+        map_(map) {
+    ASSERT(true_target != NULL);
+    ASSERT(false_target != NULL);
     ASSERT(!map.is_null());
   }
 
-  virtual HBasicBlock* FirstSuccessor() const { return true_destination_; }
-  virtual HBasicBlock* SecondSuccessor() const { return false_destination_; }
-
-  HBasicBlock* true_destination() const { return true_destination_; }
-  HBasicBlock* false_destination() const { return false_destination_; }
-
   virtual void PrintDataTo(StringStream* stream) const;
 
   Handle<Map> map() const { return map_; }
 
-  DECLARE_CONCRETE_INSTRUCTION(CompareMapAndBranch, "compare_map_and_branch")
+  DECLARE_CONCRETE_INSTRUCTION(CompareMap, "compare_map")
 
  private:
   Handle<Map> map_;
-  HBasicBlock* true_destination_;
-  HBasicBlock* false_destination_;
 };
 
 
 class HReturn: public HUnaryControlInstruction {
  public:
-  explicit HReturn(HValue* result) : HUnaryControlInstruction(result) { }
-
-  virtual void PrintDataTo(StringStream* stream) const;
+  explicit HReturn(HValue* value)
+      : HUnaryControlInstruction(value, NULL, NULL) {
+  }
 
   DECLARE_CONCRETE_INSTRUCTION(Return, "return")
 };
 
 
 class HThrow: public HUnaryControlInstruction {
  public:
-  explicit HThrow(HValue* value) : HUnaryControlInstruction(value) { }
-
-  virtual void PrintDataTo(StringStream* stream) const;
+  explicit HThrow(HValue* value)
+      : HUnaryControlInstruction(value, NULL, NULL) { }
 
   DECLARE_CONCRETE_INSTRUCTION(Throw, "throw")
 };
 
 
 class HUnaryOperation: public HInstruction {
  public:
   explicit HUnaryOperation(HValue* value) {
     SetOperandAt(0, value);
   }
@@ skipping 101 matching lines @@
   }
   void AddPushedValue(HValue* value) {
     AddValue(kNoIndex, value);
   }
   virtual int OperandCount() const { return values_.length(); }
   virtual HValue* OperandAt(int index) const { return values_[index]; }
 
   DECLARE_CONCRETE_INSTRUCTION(Simulate, "simulate")
 
 #ifdef DEBUG
-  virtual void Verify() const;
+  virtual void Verify();
 #endif
 
  protected:
   virtual void InternalSetOperandAt(int index, HValue* value) {
     values_[index] = value;
   }
 
  private:
   static const int kNoIndex = -1;
   void AddValue(int index, HValue* value) {
@@ skipping 75 matching lines @@
 
 class HGlobalObject: public HInstruction {
  public:
   HGlobalObject() {
     set_representation(Representation::Tagged());
     SetFlag(kUseGVN);
     SetFlag(kDependsOnCalls);
   }
 
   DECLARE_CONCRETE_INSTRUCTION(GlobalObject, "global_object")
+
+ protected:
+  virtual bool DataEquals(HValue* other) const { return true; }
 };
 
 
 class HGlobalReceiver: public HInstruction {
  public:
   HGlobalReceiver() {
     set_representation(Representation::Tagged());
     SetFlag(kUseGVN);
     SetFlag(kDependsOnCalls);
   }
 
   DECLARE_CONCRETE_INSTRUCTION(GlobalReceiver, "global_receiver")
+
+ protected:
+  virtual bool DataEquals(HValue* other) const { return true; }
 };
 
 
 class HCall: public HInstruction {
  public:
   // Construct a call with uninitialized arguments. The argument count
   // includes the receiver.
   explicit HCall(int count);
 
   virtual HType CalculateInferredType() const { return HType::Tagged(); }
@@ skipping 171 matching lines @@
     set_representation(Representation::Tagged());
     SetFlag(kDependsOnArrayLengths);
     SetFlag(kUseGVN);
   }
 
   virtual Representation RequiredInputRepresentation(int index) const {
     return Representation::Tagged();
   }
 
   DECLARE_CONCRETE_INSTRUCTION(JSArrayLength, "js_array_length")
+
+ protected:
+  virtual bool DataEquals(HValue* other) const { return true; }
 };
 
 
 class HFixedArrayLength: public HUnaryOperation {
  public:
   explicit HFixedArrayLength(HValue* value) : HUnaryOperation(value) {
     set_representation(Representation::Tagged());
     SetFlag(kDependsOnArrayLengths);
     SetFlag(kUseGVN);
   }
 
   virtual Representation RequiredInputRepresentation(int index) const {
     return Representation::Tagged();
   }
 
   DECLARE_CONCRETE_INSTRUCTION(FixedArrayLength, "fixed_array_length")
+
+ protected:
+  virtual bool DataEquals(HValue* other) const { return true; }
 };
 
 
 class HBitNot: public HUnaryOperation {
  public:
   explicit HBitNot(HValue* value) : HUnaryOperation(value) {
     set_representation(Representation::Integer32());
     SetFlag(kUseGVN);
     SetFlag(kTruncatingToInt32);
   }
 
   virtual Representation RequiredInputRepresentation(int index) const {
     return Representation::Integer32();
   }
   virtual HType CalculateInferredType() const;
 
   DECLARE_CONCRETE_INSTRUCTION(BitNot, "bit_not")
+
+ protected:
+  virtual bool DataEquals(HValue* other) const { return true; }
 };
 
 
 class HUnaryMathOperation: public HUnaryOperation {
  public:
   HUnaryMathOperation(HValue* value, BuiltinFunctionId op)
       : HUnaryOperation(value), op_(op) {
     switch (op) {
       case kMathFloor:
       case kMathRound:
@@ skipping 75 matching lines @@
     set_representation(Representation::Tagged());
     SetFlag(kUseGVN);
     SetFlag(kDependsOnMaps);
   }
 
   virtual Representation RequiredInputRepresentation(int index) const {
     return Representation::Tagged();
   }
 
   DECLARE_CONCRETE_INSTRUCTION(LoadElements, "load-elements")
+
+ protected:
+  virtual bool DataEquals(HValue* other) const { return true; }
 };
 
 
 class HCheckMap: public HUnaryOperation {
  public:
   HCheckMap(HValue* value, Handle<Map> map)
       : HUnaryOperation(value), map_(map) {
     set_representation(Representation::Tagged());
     SetFlag(kUseGVN);
     SetFlag(kDependsOnMaps);
   }
 
+  virtual bool IsCheckInstruction() const { return true; }
+
   virtual Representation RequiredInputRepresentation(int index) const {
     return Representation::Tagged();
   }
   virtual void PrintDataTo(StringStream* stream) const;
   virtual HType CalculateInferredType() const;
 
 #ifdef DEBUG
-  virtual void Verify() const;
+  virtual void Verify();
 #endif
 
   Handle<Map> map() const { return map_; }
 
   DECLARE_CONCRETE_INSTRUCTION(CheckMap, "check_map")
 
  protected:
   virtual bool DataEquals(HValue* other) const {
     HCheckMap* b = HCheckMap::cast(other);
     return map_.is_identical_to(b->map());
   }
 
  private:
   Handle<Map> map_;
 };
 
 
 class HCheckFunction: public HUnaryOperation {
  public:
   HCheckFunction(HValue* value, Handle<JSFunction> function)
       : HUnaryOperation(value), target_(function) {
     set_representation(Representation::Tagged());
     SetFlag(kUseGVN);
   }
 
+  virtual bool IsCheckInstruction() const { return true; }
+
   virtual Representation RequiredInputRepresentation(int index) const {
     return Representation::Tagged();
   }
   virtual void PrintDataTo(StringStream* stream) const;
   virtual HType CalculateInferredType() const;
 
 #ifdef DEBUG
-  virtual void Verify() const;
+  virtual void Verify();
 #endif
 
   Handle<JSFunction> target() const { return target_; }
 
   DECLARE_CONCRETE_INSTRUCTION(CheckFunction, "check_function")
 
  protected:
   virtual bool DataEquals(HValue* other) const {
     HCheckFunction* b = HCheckFunction::cast(other);
     return target_.is_identical_to(b->target());
   }
 
  private:
   Handle<JSFunction> target_;
 };
 
 
 class HCheckInstanceType: public HUnaryOperation {
  public:
   // Check that the instance type is in the range [first, last] where
   // both first and last are included.
   HCheckInstanceType(HValue* value, InstanceType first, InstanceType last)
       : HUnaryOperation(value), first_(first), last_(last) {
     ASSERT(first <= last);
     set_representation(Representation::Tagged());
     SetFlag(kUseGVN);
+    if ((FIRST_STRING_TYPE < first && last <= LAST_STRING_TYPE) ||
+        (FIRST_STRING_TYPE <= first && last < LAST_STRING_TYPE)) {
+      // A particular string instance type can change because of GC or
+      // externalization, but the value still remains a string.
+      SetFlag(kDependsOnMaps);
+    }
   }
 
+  virtual bool IsCheckInstruction() const { return true; }
+
   virtual Representation RequiredInputRepresentation(int index) const {
     return Representation::Tagged();
   }
 
 #ifdef DEBUG
-  virtual void Verify() const;
+  virtual void Verify();
 #endif
 
   static HCheckInstanceType* NewIsJSObjectOrJSFunction(HValue* value);
 
   InstanceType first() const { return first_; }
   InstanceType last() const { return last_; }
 
   DECLARE_CONCRETE_INSTRUCTION(CheckInstanceType, "check_instance_type")
 
  protected:
@@ skipping 11 matching lines @@
 };
 
 
 class HCheckNonSmi: public HUnaryOperation {
  public:
   explicit HCheckNonSmi(HValue* value) : HUnaryOperation(value) {
     set_representation(Representation::Tagged());
     SetFlag(kUseGVN);
   }
 
+  virtual bool IsCheckInstruction() const { return true; }
+
   virtual Representation RequiredInputRepresentation(int index) const {
     return Representation::Tagged();
   }
 
   virtual HType CalculateInferredType() const;
 
 #ifdef DEBUG
-  virtual void Verify() const;
+  virtual void Verify();
 #endif
 
   DECLARE_CONCRETE_INSTRUCTION(CheckNonSmi, "check_non_smi")
+
+ protected:
+  virtual bool DataEquals(HValue* other) const { return true; }
 };
 
 
 class HCheckPrototypeMaps: public HInstruction {
  public:
   HCheckPrototypeMaps(Handle<JSObject> prototype, Handle<JSObject> holder)
       : prototype_(prototype), holder_(holder) {
     SetFlag(kUseGVN);
     SetFlag(kDependsOnMaps);
   }
 
+  virtual bool IsCheckInstruction() const { return true; }
+
 #ifdef DEBUG
-  virtual void Verify() const;
+  virtual void Verify();
 #endif
 
   Handle<JSObject> prototype() const { return prototype_; }
   Handle<JSObject> holder() const { return holder_; }
 
   DECLARE_CONCRETE_INSTRUCTION(CheckPrototypeMaps, "check_prototype_maps")
 
   virtual intptr_t Hashcode() const {
     ASSERT(!HEAP->IsAllocationAllowed());
     intptr_t hash = reinterpret_cast<intptr_t>(*prototype());
@@ skipping 14 matching lines @@
 };
 
 
 class HCheckSmi: public HUnaryOperation {
  public:
   explicit HCheckSmi(HValue* value) : HUnaryOperation(value) {
     set_representation(Representation::Tagged());
     SetFlag(kUseGVN);
   }
 
+  virtual bool IsCheckInstruction() const { return true; }
+
   virtual Representation RequiredInputRepresentation(int index) const {
     return Representation::Tagged();
   }
   virtual HType CalculateInferredType() const;
 
 #ifdef DEBUG
-  virtual void Verify() const;
+  virtual void Verify();
 #endif
 
   DECLARE_CONCRETE_INSTRUCTION(CheckSmi, "check_smi")
+
+ protected:
+  virtual bool DataEquals(HValue* other) const { return true; }
 };
 
 
 class HPhi: public HValue {
  public:
   explicit HPhi(int merged_index)
       : inputs_(2),
         merged_index_(merged_index),
         phi_id_(-1) {
     for (int i = 0; i < Representation::kNumRepresentations; i++) {
@@ skipping 32 matching lines @@
 
   bool HasReceiverOperand();
 
   int merged_index() const { return merged_index_; }
 
   virtual const char* Mnemonic() const { return "phi"; }
 
   virtual void PrintTo(StringStream* stream) const;
 
 #ifdef DEBUG
-  virtual void Verify() const;
+  virtual void Verify();
 #endif
 
   DECLARE_INSTRUCTION(Phi)
 
   void InitRealUses(int id);
   void AddNonPhiUsesFrom(HPhi* other);
   void AddIndirectUsesTo(int* use_count);
 
   int tagged_non_phi_uses() const {
     return non_phi_uses_[Representation::kTagged];
@@ skipping 67 matching lines @@
     return double_value_;
   }
   bool HasStringValue() const { return handle_->IsString(); }
 
   virtual intptr_t Hashcode() const {
     ASSERT(!HEAP->allow_allocation(false));
     return reinterpret_cast<intptr_t>(*handle());
   }
 
 #ifdef DEBUG
-  virtual void Verify() const { }
+  virtual void Verify() { }
 #endif
 
   DECLARE_CONCRETE_INSTRUCTION(Constant, "constant")
 
  protected:
   virtual Range* InferRange();
 
   virtual bool DataEquals(HValue* other) const {
     HConstant* other_constant = HConstant::cast(other);
     return handle().is_identical_to(other_constant->handle());
@@ skipping 98 matching lines @@
 class HArgumentsElements: public HInstruction {
  public:
   HArgumentsElements() {
     // The value produced by this instruction is a pointer into the stack
     // that looks as if it was a smi because of alignment.
     set_representation(Representation::Tagged());
     SetFlag(kUseGVN);
   }
 
   DECLARE_CONCRETE_INSTRUCTION(ArgumentsElements, "arguments_elements")
+
+ protected:
+  virtual bool DataEquals(HValue* other) const { return true; }
 };
 
 
 class HArgumentsLength: public HUnaryOperation {
  public:
   explicit HArgumentsLength(HValue* value) : HUnaryOperation(value) {
     set_representation(Representation::Integer32());
     SetFlag(kUseGVN);
   }
 
   DECLARE_CONCRETE_INSTRUCTION(ArgumentsLength, "arguments_length")
+
+ protected:
+  virtual bool DataEquals(HValue* other) const { return true; }
 };
 
 
 class HAccessArgumentsAt: public HInstruction {
  public:
   HAccessArgumentsAt(HValue* arguments, HValue* length, HValue* index) {
     set_representation(Representation::Tagged());
     SetFlag(kUseGVN);
     SetOperandAt(0, arguments);
     SetOperandAt(1, length);
@@ skipping 16 matching lines @@
   virtual int OperandCount() const { return operands_.length(); }
   virtual HValue* OperandAt(int index) const { return operands_[index]; }
 
   DECLARE_CONCRETE_INSTRUCTION(AccessArgumentsAt, "access_arguments_at")
 
  protected:
   virtual void InternalSetOperandAt(int index, HValue* value) {
     operands_[index] = value;
   }
 
+  virtual bool DataEquals(HValue* other) const { return true; }
+
  private:
   HOperandVector<3> operands_;
 };
 
 
 class HBoundsCheck: public HBinaryOperation {
  public:
   HBoundsCheck(HValue* index, HValue* length)
       : HBinaryOperation(index, length) {
     SetFlag(kUseGVN);
   }
 
+  virtual bool IsCheckInstruction() const { return true; }
+
   virtual Representation RequiredInputRepresentation(int index) const {
     return Representation::Integer32();
   }
 
 #ifdef DEBUG
-  virtual void Verify() const;
+  virtual void Verify();
 #endif
 
   HValue* index() const { return left(); }
   HValue* length() const { return right(); }
 
   DECLARE_CONCRETE_INSTRUCTION(BoundsCheck, "bounds_check")
+
+ protected:
+  virtual bool DataEquals(HValue* other) const { return true; }
 };
 
 
 class HBitwiseBinaryOperation: public HBinaryOperation {
  public:
   HBitwiseBinaryOperation(HValue* left, HValue* right)
       : HBinaryOperation(left, right) {
-    // Default to truncating, Integer32, UseGVN.
-    set_representation(Representation::Integer32());
-    SetFlag(kTruncatingToInt32);
-    SetFlag(kUseGVN);
+    set_representation(Representation::Tagged());
+    SetFlag(kFlexibleRepresentation);
+    SetAllSideEffects();
   }
 
   virtual Representation RequiredInputRepresentation(int index) const {
-    return Representation::Integer32();
+    return representation();
   }
 
+  virtual void RepresentationChanged(Representation to) {
+    if (!to.IsTagged()) {
+      ASSERT(to.IsInteger32());
+      ClearAllSideEffects();
+      SetFlag(kTruncatingToInt32);
+      SetFlag(kUseGVN);
+    }
+  }
+
+  HType CalculateInferredType() const;
+
   DECLARE_INSTRUCTION(BitwiseBinaryOperation)
 };
 
 
 class HArithmeticBinaryOperation: public HBinaryOperation {
  public:
   HArithmeticBinaryOperation(HValue* left, HValue* right)
       : HBinaryOperation(left, right) {
     set_representation(Representation::Tagged());
     SetFlag(kFlexibleRepresentation);
-    SetFlagMask(AllSideEffects());
+    SetAllSideEffects();
   }
 
   virtual void RepresentationChanged(Representation to) {
     if (!to.IsTagged()) {
-      ClearFlagMask(AllSideEffects());
+      ClearAllSideEffects();
       SetFlag(kUseGVN);
     }
   }
 
   virtual HType CalculateInferredType() const;
   virtual Representation RequiredInputRepresentation(int index) const {
     return representation();
   }
   virtual Representation InferredRepresentation() const {
     if (left()->representation().Equals(right()->representation())) {
       return left()->representation();
     }
     return HValue::InferredRepresentation();
   }
 
   DECLARE_INSTRUCTION(ArithmeticBinaryOperation)
 };
 
 
 class HCompare: public HBinaryOperation {
  public:
   HCompare(HValue* left, HValue* right, Token::Value token)
       : HBinaryOperation(left, right), token_(token) {
     ASSERT(Token::IsCompareOp(token));
     set_representation(Representation::Tagged());
-    SetFlagMask(AllSideEffects());
+    SetAllSideEffects();
   }
 
   void SetInputRepresentation(Representation r);
   virtual bool EmitAtUses() const { return uses()->length() <= 1; }
   virtual Representation RequiredInputRepresentation(int index) const {
     return input_representation_;
   }
   Representation GetInputRepresentation() const {
     return input_representation_;
   }
@@ skipping 28 matching lines @@
     SetFlag(kUseGVN);
   }
 
   virtual bool EmitAtUses() const { return uses()->length() <= 1; }
   virtual Representation RequiredInputRepresentation(int index) const {
     return Representation::Tagged();
   }
   virtual HType CalculateInferredType() const;
 
   DECLARE_CONCRETE_INSTRUCTION(CompareJSObjectEq, "compare-js-object-eq")
+
+ protected:
+  virtual bool DataEquals(HValue* other) const { return true; }
 };
 
 
 class HUnaryPredicate: public HUnaryOperation {
  public:
   explicit HUnaryPredicate(HValue* value) : HUnaryOperation(value) {
     set_representation(Representation::Tagged());
     SetFlag(kUseGVN);
   }
   virtual bool EmitAtUses() const { return uses()->length() <= 1; }
@@ skipping 22 matching lines @@
  private:
   bool is_strict_;
 };
 
 
 class HIsObject: public HUnaryPredicate {
  public:
   explicit HIsObject(HValue* value) : HUnaryPredicate(value) { }
 
   DECLARE_CONCRETE_INSTRUCTION(IsObject, "is_object")
+
+ protected:
+  virtual bool DataEquals(HValue* other) const { return true; }
 };
 
 
 class HIsSmi: public HUnaryPredicate {
  public:
   explicit HIsSmi(HValue* value) : HUnaryPredicate(value) { }
 
   DECLARE_CONCRETE_INSTRUCTION(IsSmi, "is_smi")
+
+ protected:
+  virtual bool DataEquals(HValue* other) const { return true; }
 };
 
 
 class HHasInstanceType: public HUnaryPredicate {
  public:
   HHasInstanceType(HValue* value, InstanceType type)
       : HUnaryPredicate(value), from_(type), to_(type) { }
   HHasInstanceType(HValue* value, InstanceType from, InstanceType to)
       : HUnaryPredicate(value), from_(from), to_(to) {
     ASSERT(to == LAST_TYPE);  // Others not implemented yet in backend.
@@ skipping 16 matching lines @@
   InstanceType from_;
   InstanceType to_;  // Inclusive range, not all combinations work.
 };
 
 
 class HHasCachedArrayIndex: public HUnaryPredicate {
  public:
   explicit HHasCachedArrayIndex(HValue* value) : HUnaryPredicate(value) { }
 
   DECLARE_CONCRETE_INSTRUCTION(HasCachedArrayIndex, "has_cached_array_index")
+
+ protected:
+  virtual bool DataEquals(HValue* other) const { return true; }
 };
 
 
 class HClassOfTest: public HUnaryPredicate {
  public:
   HClassOfTest(HValue* value, Handle<String> class_name)
       : HUnaryPredicate(value), class_name_(class_name) { }
 
   DECLARE_CONCRETE_INSTRUCTION(ClassOfTest, "class_of_test")
 
@@ skipping 30 matching lines @@
 
  private:
   Handle<String> type_literal_;
 };
 
 
 class HInstanceOf: public HBinaryOperation {
  public:
   HInstanceOf(HValue* left, HValue* right) : HBinaryOperation(left, right) {
     set_representation(Representation::Tagged());
-    SetFlagMask(AllSideEffects());
+    SetAllSideEffects();
   }
 
   virtual bool EmitAtUses() const { return uses()->length() <= 1; }
 
   virtual Representation RequiredInputRepresentation(int index) const {
     return Representation::Tagged();
   }
 
   DECLARE_CONCRETE_INSTRUCTION(InstanceOf, "instance_of")
 };
 
 
 class HInstanceOfKnownGlobal: public HUnaryOperation {
  public:
   HInstanceOfKnownGlobal(HValue* left, Handle<JSFunction> right)
       : HUnaryOperation(left), function_(right) {
     set_representation(Representation::Tagged());
-    SetFlagMask(AllSideEffects());
+    SetAllSideEffects();
   }
 
   Handle<JSFunction> function() { return function_; }
 
   virtual Representation RequiredInputRepresentation(int index) const {
     return Representation::Tagged();
   }
 
   DECLARE_CONCRETE_INSTRUCTION(InstanceOfKnownGlobal,
                                "instance_of_known_global")
 
  private:
   Handle<JSFunction> function_;
 };
 
 
 class HPower: public HBinaryOperation {
  public:
   HPower(HValue* left, HValue* right)
       : HBinaryOperation(left, right) {
     set_representation(Representation::Double());
     SetFlag(kUseGVN);
   }
 
   virtual Representation RequiredInputRepresentation(int index) const {
     return (index == 1) ? Representation::None() : Representation::Double();
   }
 
   DECLARE_CONCRETE_INSTRUCTION(Power, "power")
+
+ protected:
+  virtual bool DataEquals(HValue* other) const { return true; }
 };
 
 
 class HAdd: public HArithmeticBinaryOperation {
  public:
   HAdd(HValue* left, HValue* right) : HArithmeticBinaryOperation(left, right) {
     SetFlag(kCanOverflow);
   }
 
   // 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 {
     return !representation().IsTagged();
   }
 
   virtual HValue* EnsureAndPropagateNotMinusZero(BitVector* visited);
 
   virtual HType CalculateInferredType() const;
 
   DECLARE_CONCRETE_INSTRUCTION(Add, "add")
 
  protected:
+  virtual bool DataEquals(HValue* other) const { return true; }
+
   virtual Range* InferRange();
 };
 
 
 class HSub: public HArithmeticBinaryOperation {
  public:
   HSub(HValue* left, HValue* right) : HArithmeticBinaryOperation(left, right) {
     SetFlag(kCanOverflow);
   }
 
   virtual HValue* EnsureAndPropagateNotMinusZero(BitVector* visited);
 
   DECLARE_CONCRETE_INSTRUCTION(Sub, "sub")
 
  protected:
+  virtual bool DataEquals(HValue* other) const { return true; }
+
   virtual Range* InferRange();
 };
 
 
 class HMul: public HArithmeticBinaryOperation {
  public:
   HMul(HValue* left, HValue* right) : HArithmeticBinaryOperation(left, right) {
     SetFlag(kCanOverflow);
   }
 
   virtual HValue* EnsureAndPropagateNotMinusZero(BitVector* visited);
 
   // Only commutative if it is certain that not two objects are multiplicated.
   virtual bool IsCommutative() const {
     return !representation().IsTagged();
   }
 
   DECLARE_CONCRETE_INSTRUCTION(Mul, "mul")
 
  protected:
+  virtual bool DataEquals(HValue* other) const { return true; }
+
   virtual Range* InferRange();
 };
 
 
 class HMod: public HArithmeticBinaryOperation {
  public:
   HMod(HValue* left, HValue* right) : HArithmeticBinaryOperation(left, right) {
     SetFlag(kCanBeDivByZero);
   }
 
   virtual HValue* EnsureAndPropagateNotMinusZero(BitVector* visited);
 
   DECLARE_CONCRETE_INSTRUCTION(Mod, "mod")
 
  protected:
+  virtual bool DataEquals(HValue* other) const { return true; }
+
   virtual Range* InferRange();
 };
 
 
 class HDiv: public HArithmeticBinaryOperation {
  public:
   HDiv(HValue* left, HValue* right) : HArithmeticBinaryOperation(left, right) {
     SetFlag(kCanBeDivByZero);
     SetFlag(kCanOverflow);
   }
 
   virtual HValue* EnsureAndPropagateNotMinusZero(BitVector* visited);
 
   DECLARE_CONCRETE_INSTRUCTION(Div, "div")
 
  protected:
+  virtual bool DataEquals(HValue* other) const { return true; }
+
   virtual Range* InferRange();
 };
 
 
 class HBitAnd: public HBitwiseBinaryOperation {
  public:
   HBitAnd(HValue* left, HValue* right)
       : HBitwiseBinaryOperation(left, right) { }
 
   virtual bool IsCommutative() const { return true; }
   virtual HType CalculateInferredType() const;
 
   DECLARE_CONCRETE_INSTRUCTION(BitAnd, "bit_and")
 
  protected:
+  virtual bool DataEquals(HValue* other) const { return true; }
+
   virtual Range* InferRange();
 };
 
 
 class HBitXor: public HBitwiseBinaryOperation {
  public:
   HBitXor(HValue* left, HValue* right)
       : HBitwiseBinaryOperation(left, right) { }
 
   virtual bool IsCommutative() const { return true; }
   virtual HType CalculateInferredType() const;
 
   DECLARE_CONCRETE_INSTRUCTION(BitXor, "bit_xor")
+
+ protected:
+  virtual bool DataEquals(HValue* other) const { return true; }
 };
 
 
 class HBitOr: public HBitwiseBinaryOperation {
  public:
   HBitOr(HValue* left, HValue* right)
       : HBitwiseBinaryOperation(left, right) { }
 
   virtual bool IsCommutative() const { return true; }
   virtual HType CalculateInferredType() const;
 
   DECLARE_CONCRETE_INSTRUCTION(BitOr, "bit_or")
 
  protected:
+  virtual bool DataEquals(HValue* other) const { return true; }
+
   virtual Range* InferRange();
 };
 
 
 class HShl: public HBitwiseBinaryOperation {
  public:
   HShl(HValue* left, HValue* right)
       : HBitwiseBinaryOperation(left, right) { }
 
   virtual Range* InferRange();
   virtual HType CalculateInferredType() const;
 
   DECLARE_CONCRETE_INSTRUCTION(Shl, "shl")
+
+ protected:
+  virtual bool DataEquals(HValue* other) const { return true; }
 };
 
 
 class HShr: public HBitwiseBinaryOperation {
  public:
   HShr(HValue* left, HValue* right)
       : HBitwiseBinaryOperation(left, right) { }
 
   virtual HType CalculateInferredType() const;
 
   DECLARE_CONCRETE_INSTRUCTION(Shr, "shr")
+
+ protected:
+  virtual bool DataEquals(HValue* other) const { return true; }
 };
 
 
 class HSar: public HBitwiseBinaryOperation {
  public:
   HSar(HValue* left, HValue* right)
       : HBitwiseBinaryOperation(left, right) { }
 
   virtual Range* InferRange();
   virtual HType CalculateInferredType() const;
 
   DECLARE_CONCRETE_INSTRUCTION(Sar, "sar")
+
+ protected:
+  virtual bool DataEquals(HValue* other) const { return true; }
 };
 
 
 class HOsrEntry: public HInstruction {
  public:
   explicit HOsrEntry(int ast_id) : ast_id_(ast_id) {
     SetFlag(kChangesOsrEntries);
   }
 
   int ast_id() const { return ast_id_; }
@@ skipping 22 matching lines @@
 };
 
 
 class HCallStub: public HInstruction {
  public:
   HCallStub(CodeStub::Major major_key, int argument_count)
       : major_key_(major_key),
         argument_count_(argument_count),
         transcendental_type_(TranscendentalCache::kNumberOfCaches) {
     set_representation(Representation::Tagged());
-    SetFlagMask(AllSideEffects());
+    SetAllSideEffects();
   }
 
   CodeStub::Major major_key() { return major_key_; }
   int argument_count() { return argument_count_; }
 
   void set_transcendental_type(TranscendentalCache::Type transcendental_type) {
     transcendental_type_ = transcendental_type;
   }
   TranscendentalCache::Type transcendental_type() {
     return transcendental_type_;
@@ skipping 62 matching lines @@
 
   Handle<JSGlobalPropertyCell> cell() const { return cell_; }
 
   virtual Representation RequiredInputRepresentation(int index) const {
     return Representation::Tagged();
   }
   virtual void PrintDataTo(StringStream* stream) const;
 
   DECLARE_CONCRETE_INSTRUCTION(StoreGlobal, "store_global")
 
- protected:
-  virtual bool DataEquals(HValue* other) const {
-    HStoreGlobal* b = HStoreGlobal::cast(other);
-    return cell_.is_identical_to(b->cell());
-  }
-
  private:
   Handle<JSGlobalPropertyCell> cell_;
 };
 
 
+class HLoadContextSlot: public HInstruction {
+ public:
+  HLoadContextSlot(int context_chain_length , int slot_index)
+      : context_chain_length_(context_chain_length), slot_index_(slot_index) {
+    set_representation(Representation::Tagged());
+    SetFlag(kUseGVN);
+    SetFlag(kDependsOnCalls);
+  }
+
+  int context_chain_length() const { return context_chain_length_; }
+  int slot_index() const { return slot_index_; }
+
+  virtual void PrintDataTo(StringStream* stream) const;
+
+  virtual intptr_t Hashcode() const {
+    return context_chain_length() * 29 + slot_index();
+  }
+
+  DECLARE_CONCRETE_INSTRUCTION(LoadContextSlot, "load_context_slot")
+
+ protected:
+  virtual bool DataEquals(HValue* other) const {
+    HLoadContextSlot* b = HLoadContextSlot::cast(other);
+    return (context_chain_length() == b->context_chain_length())
+        && (slot_index() == b->slot_index());
+  }
+
+ private:
+  int context_chain_length_;
+  int slot_index_;
+};
+
+
 class HLoadNamedField: public HUnaryOperation {
  public:
   HLoadNamedField(HValue* object, bool is_in_object, int offset)
       : HUnaryOperation(object),
         is_in_object_(is_in_object),
         offset_(offset) {
     set_representation(Representation::Tagged());
     SetFlag(kUseGVN);
     if (is_in_object) {
       SetFlag(kDependsOnInobjectFields);
@@ skipping 23 matching lines @@
   bool is_in_object_;
   int offset_;
 };
 
 
 class HLoadNamedGeneric: public HUnaryOperation {
  public:
   HLoadNamedGeneric(HValue* object, Handle<Object> name)
       : HUnaryOperation(object), name_(name) {
     set_representation(Representation::Tagged());
-    SetFlagMask(AllSideEffects());
+    SetAllSideEffects();
   }
 
   HValue* object() const { return OperandAt(0); }
   Handle<Object> name() const { return name_; }
 
   virtual Representation RequiredInputRepresentation(int index) const {
     return Representation::Tagged();
   }
 
   DECLARE_CONCRETE_INSTRUCTION(LoadNamedGeneric, "load_named_generic")
 
- protected:
-  virtual bool DataEquals(HValue* other) const {
-    HLoadNamedGeneric* b = HLoadNamedGeneric::cast(other);
-    return name_.is_identical_to(b->name_);
-  }
-
  private:
   Handle<Object> name_;
 };
 
 
 class HLoadFunctionPrototype: public HUnaryOperation {
  public:
   explicit HLoadFunctionPrototype(HValue* function)
       : HUnaryOperation(function) {
     set_representation(Representation::Tagged());
-    SetFlagMask(kDependsOnFunctionPrototypes);
+    SetFlag(kUseGVN);
+    SetFlag(kDependsOnCalls);
   }
 
   HValue* function() const { return OperandAt(0); }
 
   virtual Representation RequiredInputRepresentation(int index) const {
     return Representation::Tagged();
   }
 
   DECLARE_CONCRETE_INSTRUCTION(LoadFunctionPrototype, "load_function_prototype")
 
@@ skipping 28 matching lines @@
   }
 
   virtual Representation RequiredInputRepresentation(int index) const {
     // The key is supposed to be Integer32.
     return (index == 1) ? Representation::Integer32()
         : Representation::Tagged();
   }
 
   DECLARE_CONCRETE_INSTRUCTION(LoadKeyedFastElement,
                                "load_keyed_fast_element")
+
+ protected:
+  virtual bool DataEquals(HValue* other) const { return true; }
 };
 
 
 class HLoadKeyedGeneric: public HLoadKeyed {
  public:
   HLoadKeyedGeneric(HValue* obj, HValue* key) : HLoadKeyed(obj, key) {
-    SetFlagMask(AllSideEffects());
+    SetAllSideEffects();
   }
 
   DECLARE_CONCRETE_INSTRUCTION(LoadKeyedGeneric, "load_keyed_generic")
 };
 
 
 static inline bool StoringValueNeedsWriteBarrier(HValue* value) {
   return !value->type().IsSmi() &&
       !(value->IsConstant() && HConstant::cast(value)->InOldSpace());
 }
@@ skipping 15 matching lines @@
   Handle<Object> name() const { return name_; }
   HValue* value() const { return OperandAt(1); }
   void set_value(HValue* value) { SetOperandAt(1, value); }
 
   bool NeedsWriteBarrier() const {
     return StoringValueNeedsWriteBarrier(value());
   }
 
   DECLARE_INSTRUCTION(StoreNamed)
 
- protected:
-  virtual bool DataEquals(HValue* other) const {
-    HStoreNamed* b = HStoreNamed::cast(other);
-    return name_.is_identical_to(b->name_);
-  }
-
  private:
   Handle<Object> name_;
 };
 
 
 class HStoreNamedField: public HStoreNamed {
  public:
   HStoreNamedField(HValue* obj,
                    Handle<Object> name,
                    HValue* val,
@@ skipping 25 matching lines @@
   bool is_in_object_;
   int offset_;
   Handle<Map> transition_;
 };
 
 
 class HStoreNamedGeneric: public HStoreNamed {
  public:
   HStoreNamedGeneric(HValue* obj, Handle<Object> name, HValue* val)
       : HStoreNamed(obj, name, val) {
-    SetFlagMask(AllSideEffects());
+    SetAllSideEffects();
   }
 
   DECLARE_CONCRETE_INSTRUCTION(StoreNamedGeneric, "store_named_generic")
 };
 
 
 class HStoreKeyed: public HInstruction {
  public:
   HStoreKeyed(HValue* obj, HValue* key, HValue* val) {
     SetOperandAt(0, obj);
@@ skipping 44 matching lines @@
 
   DECLARE_CONCRETE_INSTRUCTION(StoreKeyedFastElement,
                                "store_keyed_fast_element")
 };
 
 
 class HStoreKeyedGeneric: public HStoreKeyed {
  public:
   HStoreKeyedGeneric(HValue* obj, HValue* key, HValue* val)
       : HStoreKeyed(obj, key, val) {
-    SetFlagMask(AllSideEffects());
+    SetAllSideEffects();
   }
 
   DECLARE_CONCRETE_INSTRUCTION(StoreKeyedGeneric, "store_keyed_generic")
 };
 
 
+class HStringCharCodeAt: public HBinaryOperation {
+ public:
+  HStringCharCodeAt(HValue* string, HValue* index)
+      : HBinaryOperation(string, index) {
+    set_representation(Representation::Integer32());
+    SetFlag(kUseGVN);
+  }
+
+  virtual Representation RequiredInputRepresentation(int index) const {
+    // The index is supposed to be Integer32.
+    return (index == 1) ? Representation::Integer32()
+        : Representation::Tagged();
+  }
+
+  HValue* string() const { return OperandAt(0); }
+  HValue* index() const { return OperandAt(1); }
+
+  DECLARE_CONCRETE_INSTRUCTION(StringCharCodeAt, "string_char_code_at")
+
+ protected:
+  virtual bool DataEquals(HValue* other) const { return true; }
+
+  virtual Range* InferRange() {
+    return new Range(0, String::kMaxUC16CharCode);
+  }
+};
+
+
+class HStringLength: public HUnaryOperation {
+ public:
+  explicit HStringLength(HValue* string) : HUnaryOperation(string) {
+    set_representation(Representation::Tagged());
+    SetFlag(kUseGVN);
+  }
+
+  virtual Representation RequiredInputRepresentation(int index) const {
+    return Representation::Tagged();
+  }
+
+  virtual HType CalculateInferredType() const {
+    STATIC_ASSERT(String::kMaxLength <= Smi::kMaxValue);
+    return HType::Smi();
+  }
+
+  DECLARE_CONCRETE_INSTRUCTION(StringLength, "string_length")
+
+ protected:
+  virtual bool DataEquals(HValue* other) const { return true; }
+
+  virtual Range* InferRange() {
+    return new Range(0, String::kMaxLength);
+  }
+};
+
+
 class HMaterializedLiteral: public HInstruction {
  public:
   HMaterializedLiteral(int index, int depth)
       : literal_index_(index), depth_(depth) {
     set_representation(Representation::Tagged());
   }
 
   int literal_index() const { return literal_index_; }
   int depth() const { return depth_; }
 
@@ skipping 107 matching lines @@
 
   DECLARE_CONCRETE_INSTRUCTION(ValueOf, "value_of")
 };
 
 
 class HDeleteProperty: public HBinaryOperation {
  public:
   HDeleteProperty(HValue* obj, HValue* key)
       : HBinaryOperation(obj, key) {
     set_representation(Representation::Tagged());
-    SetFlagMask(AllSideEffects());
+    SetAllSideEffects();
   }
 
   virtual Representation RequiredInputRepresentation(int index) const {
     return Representation::Tagged();
   }
 
   DECLARE_CONCRETE_INSTRUCTION(DeleteProperty, "delete_property")
 
   HValue* object() const { return left(); }
   HValue* key() const { return right(); }
 };
 
 #undef DECLARE_INSTRUCTION
 #undef DECLARE_CONCRETE_INSTRUCTION
 
 } }  // namespace v8::internal
 
 #endif  // V8_HYDROGEN_INSTRUCTIONS_H_