Improve inobject field tracking during GVN.

src/hydrogen-instructions.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 458 matching lines @@
 
   HUseListNode* current_;
   HUseListNode* next_;
   HValue* value_;
   int index_;
 
   friend class HValue;
 };
 
 
-// There must be one corresponding kDepends flag for every kChanges flag and
-// the order of the kChanges flags must be exactly the same as of the kDepends
-// flags. All tracked flags should appear before untracked ones.
+// All tracked flags should appear before untracked ones.
 enum GVNFlag {
   // Declare global value numbering flags.
-#define DECLARE_FLAG(type) kChanges##type, kDependsOn##type,
+#define DECLARE_FLAG(Type) k##Type,
   GVN_TRACKED_FLAG_LIST(DECLARE_FLAG)
   GVN_UNTRACKED_FLAG_LIST(DECLARE_FLAG)
 #undef DECLARE_FLAG
-  kNumberOfFlags,
-#define COUNT_FLAG(type) + 1
-  kNumberOfTrackedSideEffects = 0 GVN_TRACKED_FLAG_LIST(COUNT_FLAG)
+#define COUNT_FLAG(Type) + 1
+  kNumberOfTrackedSideEffects = 0 GVN_TRACKED_FLAG_LIST(COUNT_FLAG),
+  kNumberOfUntrackedSideEffects = 0 GVN_UNTRACKED_FLAG_LIST(COUNT_FLAG),
 #undef COUNT_FLAG
+  kNumberOfFlags = kNumberOfTrackedSideEffects + kNumberOfUntrackedSideEffects
 };
 
 
+static inline GVNFlag GVNFlagFromInt(int i) {
+  ASSERT(i >= 0);
+  ASSERT(i < kNumberOfFlags);
+  return static_cast<GVNFlag>(i);
+}
+
+
 class DecompositionResult V8_FINAL BASE_EMBEDDED {
  public:
   DecompositionResult() : base_(NULL), offset_(0), scale_(0) {}
 
   HValue* base() { return base_; }
   int offset() { return offset_; }
   int scale() { return scale_; }
 
   bool Apply(HValue* other_base, int other_offset, int other_scale = 0) {
     if (base_ == NULL) {
@@ skipping 25 matching lines @@
     *a = *b;
     *b = c;
   }
 
   HValue* base_;
   int offset_;
   int scale_;
 };
 
 
-typedef EnumSet<GVNFlag, int64_t> GVNFlagSet;
+typedef EnumSet<GVNFlag, int32_t> GVNFlagSet;
 
 
 class HValue : public ZoneObject {
  public:
   static const int kNoNumber = -1;
 
   enum Flag {
     kFlexibleRepresentation,
     kCannotBeTagged,
     // Participate in Global Value Numbering, i.e. elimination of
@@ skipping 30 matching lines @@
     // HEnvironmentMarkers are deleted before dead code
     // elimination takes place, so they can repurpose the kIsLive flag:
     kEndsLiveRange = kIsLive,
 
     // TODO(everyone): Don't forget to update this!
     kLastFlag = kIsLive
   };
 
   STATIC_ASSERT(kLastFlag < kBitsPerInt);
 
-  static const int kChangesToDependsFlagsLeftShift = 1;
-
-  static GVNFlag ChangesFlagFromInt(int x) {
-    return static_cast<GVNFlag>(x * 2);
-  }
-  static GVNFlag DependsOnFlagFromInt(int x) {
-    return static_cast<GVNFlag>(x * 2 + 1);
-  }
-  static GVNFlagSet ConvertChangesToDependsFlags(GVNFlagSet flags) {
-    return GVNFlagSet(flags.ToIntegral() << kChangesToDependsFlagsLeftShift);
-  }
-
   static HValue* cast(HValue* value) { return value; }
 
   enum Opcode {
     // Declare a unique enum value for each hydrogen instruction.
   #define DECLARE_OPCODE(type) k##type,
     HYDROGEN_CONCRETE_INSTRUCTION_LIST(DECLARE_OPCODE)
     kPhi
   #undef DECLARE_OPCODE
   };
   virtual Opcode opcode() const = 0;
@@ skipping 155 matching lines @@
   }
 
   // Returns true if the flag specified is set for all uses, false otherwise.
   bool CheckUsesForFlag(Flag f) const;
   // Same as before and the first one without the flag is returned in value.
   bool CheckUsesForFlag(Flag f, HValue** value) const;
   // Returns true if the flag specified is set for all uses, and this set
   // of uses is non-empty.
   bool HasAtLeastOneUseWithFlagAndNoneWithout(Flag f) const;
 
-  GVNFlagSet gvn_flags() const { return gvn_flags_; }
-  void SetGVNFlag(GVNFlag f) { gvn_flags_.Add(f); }
-  void ClearGVNFlag(GVNFlag f) { gvn_flags_.Remove(f); }
-  bool CheckGVNFlag(GVNFlag f) const { return gvn_flags_.Contains(f); }
-  void SetAllSideEffects() { gvn_flags_.Add(AllSideEffectsFlagSet()); }
+  GVNFlagSet ChangesFlags() const { return changes_flags_; }
+  GVNFlagSet DependsOnFlags() const { return depends_on_flags_; }
+  void SetChangesFlag(GVNFlag f) { changes_flags_.Add(f); }
+  void SetDependsOnFlag(GVNFlag f) { depends_on_flags_.Add(f); }
+  void ClearChangesFlag(GVNFlag f) { changes_flags_.Remove(f); }
+  void ClearDependsOnFlag(GVNFlag f) { depends_on_flags_.Remove(f); }
+  bool CheckChangesFlag(GVNFlag f) const {
+    return changes_flags_.Contains(f);
+  }
+  bool CheckDependsOnFlag(GVNFlag f) const {
+    return depends_on_flags_.Contains(f);
+  }
+  void SetAllSideEffects() { changes_flags_.Add(AllSideEffectsFlagSet()); }
   void ClearAllSideEffects() {
-    gvn_flags_.Remove(AllSideEffectsFlagSet());
+    changes_flags_.Remove(AllSideEffectsFlagSet());
   }
   bool HasSideEffects() const {
-    return gvn_flags_.ContainsAnyOf(AllSideEffectsFlagSet());
+    return changes_flags_.ContainsAnyOf(AllSideEffectsFlagSet());
   }
   bool HasObservableSideEffects() const {
     return !CheckFlag(kHasNoObservableSideEffects) &&
-        gvn_flags_.ContainsAnyOf(AllObservableSideEffectsFlagSet());
-  }
-
-  GVNFlagSet DependsOnFlags() const {
-    GVNFlagSet result = gvn_flags_;
-    result.Intersect(AllDependsOnFlagSet());
-    return result;
+        changes_flags_.ContainsAnyOf(AllObservableSideEffectsFlagSet());
   }
 
   GVNFlagSet SideEffectFlags() const {
-    GVNFlagSet result = gvn_flags_;
+    GVNFlagSet result = ChangesFlags();
     result.Intersect(AllSideEffectsFlagSet());
     return result;
   }
 
-  GVNFlagSet ChangesFlags() const {
-    GVNFlagSet result = gvn_flags_;
-    result.Intersect(AllChangesFlagSet());
-    return result;
-  }
-
   GVNFlagSet ObservableChangesFlags() const {
-    GVNFlagSet result = gvn_flags_;
-    result.Intersect(AllChangesFlagSet());
+    GVNFlagSet result = ChangesFlags();
     result.Intersect(AllObservableSideEffectsFlagSet());
     return result;
   }
 
   Range* range() const { return range_; }
   // TODO(svenpanne) We should really use the null object pattern here.
   bool HasRange() const { return range_ != NULL; }
   bool CanBeNegative() const { return !HasRange() || range()->CanBeNegative(); }
   bool CanBeZero() const { return !HasRange() || range()->CanBeZero(); }
   bool RangeCanInclude(int value) const {
@@ skipping 120 matching lines @@
   void clear_block() {
     ASSERT(block_ != NULL);
     block_ = NULL;
   }
 
   void set_representation(Representation r) {
     ASSERT(representation_.IsNone() && !r.IsNone());
     representation_ = r;
   }
 
-  static GVNFlagSet AllDependsOnFlagSet() {
+  static GVNFlagSet AllFlagSet() {
     GVNFlagSet result;
-    // Create changes mask.
-#define ADD_FLAG(type) result.Add(kDependsOn##type);
+#define ADD_FLAG(Type) result.Add(k##Type);
   GVN_TRACKED_FLAG_LIST(ADD_FLAG)
   GVN_UNTRACKED_FLAG_LIST(ADD_FLAG)
 #undef ADD_FLAG
-    return result;
-  }
-
-  static GVNFlagSet AllChangesFlagSet() {
-    GVNFlagSet result;
-    // Create changes mask.
-#define ADD_FLAG(type) result.Add(kChanges##type);
-  GVN_TRACKED_FLAG_LIST(ADD_FLAG)
-  GVN_UNTRACKED_FLAG_LIST(ADD_FLAG)
-#undef ADD_FLAG
     return result;
   }
 
   // A flag mask to mark an instruction as having arbitrary side effects.
   static GVNFlagSet AllSideEffectsFlagSet() {
-    GVNFlagSet result = AllChangesFlagSet();
-    result.Remove(kChangesOsrEntries);
+    GVNFlagSet result = AllFlagSet();
+    result.Remove(kOsrEntries);
     return result;
   }
 
   // A flag mask of all side effects that can make observable changes in
   // an executing program (i.e. are not safe to repeat, move or remove);
   static GVNFlagSet AllObservableSideEffectsFlagSet() {
-    GVNFlagSet result = AllChangesFlagSet();
-    result.Remove(kChangesNewSpacePromotion);
-    result.Remove(kChangesElementsKind);
-    result.Remove(kChangesElementsPointer);
-    result.Remove(kChangesMaps);
+    GVNFlagSet result = AllFlagSet();
+    result.Remove(kNewSpacePromotion);
+    result.Remove(kElementsKind);
+    result.Remove(kElementsPointer);
+    result.Remove(kMaps);
     return result;
   }
 
   // Remove the matching use from the use list if present.  Returns the
   // removed list node or NULL.
   HUseListNode* RemoveUse(HValue* value, int index);
 
   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_;
   HType type_;
   HUseListNode* use_list_;
   Range* range_;
   int flags_;
-  GVNFlagSet gvn_flags_;
+  GVNFlagSet changes_flags_;
+  GVNFlagSet depends_on_flags_;
 
  private:
   virtual bool IsDeletable() const { return false; }
 
   DISALLOW_COPY_AND_ASSIGN(HValue);
 };
 
 
 #define DECLARE_INSTRUCTION_FACTORY_P0(I)                                      \
   static I* New(Zone* zone, HValue* context) {                                 \
@@ skipping 233 matching lines @@
   virtual bool HasStackCheck() { return false; }
 
   DECLARE_ABSTRACT_INSTRUCTION(Instruction)
 
  protected:
   HInstruction(HType type = HType::Tagged())
       : HValue(type),
         next_(NULL),
         previous_(NULL),
         position_(RelocInfo::kNoPosition) {
-    SetGVNFlag(kDependsOnOsrEntries);
+    SetDependsOnFlag(kOsrEntries);
   }
 
   virtual void DeleteFromGraph() V8_OVERRIDE { Unlink(); }
 
  private:
   void InitializeAsFirst(HBasicBlock* block) {
     ASSERT(!IsLinked());
     SetBlock(block);
   }
 
@@ skipping 439 matching lines @@
     SetFlag(kUseGVN);
     if (is_truncating_to_smi) {
       SetFlag(kTruncatingToSmi);
       SetFlag(kTruncatingToInt32);
     }
     if (is_truncating_to_int32) SetFlag(kTruncatingToInt32);
     if (value->representation().IsSmi() || value->type().IsSmi()) {
       set_type(HType::Smi());
     } else {
       set_type(HType::TaggedNumber());
-      if (to.IsTagged()) SetGVNFlag(kChangesNewSpacePromotion);
+      if (to.IsTagged()) SetChangesFlag(kNewSpacePromotion);
     }
   }
 
   bool can_convert_undefined_to_nan() {
     return CheckUsesForFlag(kAllowUndefinedAsNaN);
   }
 
   virtual HValue* EnsureAndPropagateNotMinusZero(
       BitVector* visited) V8_OVERRIDE;
   virtual HType CalculateInferredType() V8_OVERRIDE;
@@ skipping 225 matching lines @@
   }
 
   bool is_function_entry() { return type_ == kFunctionEntry; }
   bool is_backwards_branch() { return type_ == kBackwardsBranch; }
 
   DECLARE_CONCRETE_INSTRUCTION(StackCheck)
 
  private:
   HStackCheck(HValue* context, Type type) : type_(type) {
     SetOperandAt(0, context);
-    SetGVNFlag(kChangesNewSpacePromotion);
+    SetChangesFlag(kNewSpacePromotion);
   }
 
   Type type_;
 };
 
 
 enum InliningKind {
   NORMAL_RETURN,          // Drop the function from the environment on return.
   CONSTRUCT_CALL_RETURN,  // Either use allocated receiver or return value.
   GETTER_CALL_RETURN,     // Returning from a getter, need to restore context.
@@ skipping 527 matching lines @@
   DECLARE_CONCRETE_INSTRUCTION(MapEnumLength)
 
  protected:
   virtual bool DataEquals(HValue* other) V8_OVERRIDE { return true; }
 
  private:
   explicit HMapEnumLength(HValue* value)
       : HUnaryOperation(value, HType::Smi()) {
     set_representation(Representation::Smi());
     SetFlag(kUseGVN);
-    SetGVNFlag(kDependsOnMaps);
+    SetDependsOnFlag(kMaps);
   }
 
   virtual bool IsDeletable() const V8_OVERRIDE { return true; }
 };
 
 
 class HUnaryMathOperation V8_FINAL : public HTemplateInstruction<2> {
  public:
   static HInstruction* New(Zone* zone,
                            HValue* context,
@@ skipping 53 matching lines @@
     switch (op) {
       case kMathFloor:
       case kMathRound:
         set_representation(Representation::Integer32());
         break;
       case kMathAbs:
         // Not setting representation here: it is None intentionally.
         SetFlag(kFlexibleRepresentation);
         // TODO(svenpanne) This flag is actually only needed if representation()
         // is tagged, and not when it is an unboxed double or unboxed integer.
-        SetGVNFlag(kChangesNewSpacePromotion);
+        SetChangesFlag(kNewSpacePromotion);
         break;
       case kMathLog:
       case kMathExp:
       case kMathSqrt:
       case kMathPowHalf:
         set_representation(Representation::Double());
         break;
       default:
         UNREACHABLE();
     }
@@ skipping 28 matching lines @@
     HLoadRoot* b = HLoadRoot::cast(other);
     return index_ == b->index_;
   }
 
  private:
   HLoadRoot(Heap::RootListIndex index, HType type = HType::Tagged())
       : HTemplateInstruction<0>(type), index_(index) {
     SetFlag(kUseGVN);
     // TODO(bmeurer): We'll need kDependsOnRoots once we add the
     // corresponding HStoreRoot instruction.
-    SetGVNFlag(kDependsOnCalls);
+    SetDependsOnFlag(kCalls);
   }
 
   virtual bool IsDeletable() const V8_OVERRIDE { return true; }
 
   const Heap::RootListIndex index_;
 };
 
 
 class HCheckMaps V8_FINAL : public HTemplateInstruction<2> {
  public:
@@ skipping 36 matching lines @@
     return this->map_set_.Equals(&HCheckMaps::cast(other)->map_set_);
   }
 
   virtual int RedefinedOperandIndex() { return 0; }
 
  private:
   void Add(Handle<Map> map, Zone* zone) {
     map_set_.Add(Unique<Map>(map), zone);
     if (!has_migration_target_ && map->is_migration_target()) {
       has_migration_target_ = true;
-      SetGVNFlag(kChangesNewSpacePromotion);
+      SetChangesFlag(kNewSpacePromotion);
     }
   }
 
   // Clients should use one of the static New* methods above.
   HCheckMaps(HValue* value, Zone *zone, HValue* typecheck)
       : HTemplateInstruction<2>(value->type()),
         omit_(false), has_migration_target_(false) {
     SetOperandAt(0, value);
     // Use the object value for the dependency if NULL is passed.
     SetOperandAt(1, typecheck != NULL ? typecheck : value);
     set_representation(Representation::Tagged());
     SetFlag(kUseGVN);
     SetFlag(kTrackSideEffectDominators);
-    SetGVNFlag(kDependsOnMaps);
-    SetGVNFlag(kDependsOnElementsKind);
+    SetDependsOnFlag(kMaps);
+    SetDependsOnFlag(kElementsKind);
   }
 
   bool omit_;
   bool has_migration_target_;
   UniqueSet<Map> map_set_;
 };
 
 
 class HCheckValue V8_FINAL : public HUnaryOperation {
  public:
@@ skipping 583 matching lines @@
   const ZoneList<HValue*>* values() const { return &values_; }
   int length() const { return values_.length(); }
   int capture_id() const { return capture_id_; }
 
   // Shortcut for the map value of this captured object.
   HValue* map_value() const { return values()->first(); }
 
   void ReuseSideEffectsFromStore(HInstruction* store) {
     ASSERT(store->HasObservableSideEffects());
     ASSERT(store->IsStoreNamedField());
-    gvn_flags_.Add(store->gvn_flags());
+    changes_flags_.Add(store->ChangesFlags());
   }
 
   // Replay effects of this instruction on the given environment.
   void ReplayEnvironment(HEnvironment* env);
 
   virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
   DECLARE_CONCRETE_INSTRUCTION(CapturedObject)
 
  private:
@@ skipping 612 matching lines @@
   HBitwiseBinaryOperation(HValue* context, HValue* left, HValue* right,
                           HType type = HType::Tagged())
       : HBinaryOperation(context, left, right, type) {
     SetFlag(kFlexibleRepresentation);
     SetFlag(kTruncatingToInt32);
     SetFlag(kAllowUndefinedAsNaN);
     SetAllSideEffects();
   }
 
   virtual void RepresentationChanged(Representation to) V8_OVERRIDE {
-    if (to.IsTagged()) SetGVNFlag(kChangesNewSpacePromotion);
+    if (to.IsTagged()) SetChangesFlag(kNewSpacePromotion);
     if (to.IsTagged() &&
         (left()->ToNumberCanBeObserved() || right()->ToNumberCanBeObserved())) {
       SetAllSideEffects();
       ClearFlag(kUseGVN);
     } else {
       ClearAllSideEffects();
       SetFlag(kUseGVN);
     }
   }
 
@@ skipping 56 matching lines @@
 class HArithmeticBinaryOperation : public HBinaryOperation {
  public:
   HArithmeticBinaryOperation(HValue* context, HValue* left, HValue* right)
       : HBinaryOperation(context, left, right, HType::TaggedNumber()) {
     SetAllSideEffects();
     SetFlag(kFlexibleRepresentation);
     SetFlag(kAllowUndefinedAsNaN);
   }
 
   virtual void RepresentationChanged(Representation to) V8_OVERRIDE {
-    if (to.IsTagged()) SetGVNFlag(kChangesNewSpacePromotion);
+    if (to.IsTagged()) SetChangesFlag(kNewSpacePromotion);
     if (to.IsTagged() &&
         (left()->ToNumberCanBeObserved() || right()->ToNumberCanBeObserved())) {
       SetAllSideEffects();
       ClearFlag(kUseGVN);
     } else {
       ClearAllSideEffects();
       SetFlag(kUseGVN);
     }
   }
 
@@ skipping 304 matching lines @@
   HStringCompareAndBranch(HValue* context,
                           HValue* left,
                           HValue* right,
                           Token::Value token)
       : token_(token) {
     ASSERT(Token::IsCompareOp(token));
     SetOperandAt(0, context);
     SetOperandAt(1, left);
     SetOperandAt(2, right);
     set_representation(Representation::Tagged());
-    SetGVNFlag(kChangesNewSpacePromotion);
+    SetChangesFlag(kNewSpacePromotion);
   }
 
   Token::Value token_;
 };
 
 
 class HIsConstructCallAndBranch : public HTemplateControlInstruction<2, 0> {
  public:
   DECLARE_INSTRUCTION_FACTORY_P0(HIsConstructCallAndBranch);
 
@@ skipping 204 matching lines @@
 
  protected:
   virtual bool DataEquals(HValue* other) V8_OVERRIDE { return true; }
 
  private:
   HPower(HValue* left, HValue* right) {
     SetOperandAt(0, left);
     SetOperandAt(1, right);
     set_representation(Representation::Double());
     SetFlag(kUseGVN);
-    SetGVNFlag(kChangesNewSpacePromotion);
+    SetChangesFlag(kNewSpacePromotion);
   }
 
   virtual bool IsDeletable() const V8_OVERRIDE {
     return !right()->representation().IsTagged();
   }
 };
 
 
 class HAdd V8_FINAL : public HArithmeticBinaryOperation {
  public:
@@ skipping 21 matching lines @@
     } else if (right()->IsInteger32Constant()) {
       decomposition->Apply(left(), right()->GetInteger32Constant());
       return true;
     } else {
       return false;
     }
   }
 
   virtual void RepresentationChanged(Representation to) V8_OVERRIDE {
     if (to.IsTagged()) {
-      SetGVNFlag(kChangesNewSpacePromotion);
+      SetChangesFlag(kNewSpacePromotion);
       ClearFlag(kAllowUndefinedAsNaN);
     }
     if (to.IsTagged() &&
         (left()->ToNumberCanBeObserved() || right()->ToNumberCanBeObserved() ||
          left()->ToStringCanBeObserved() || right()->ToStringCanBeObserved())) {
       SetAllSideEffects();
       ClearFlag(kUseGVN);
     } else {
       ClearAllSideEffects();
       SetFlag(kUseGVN);
@@ skipping 436 matching lines @@
   BailoutId ast_id() const { return ast_id_; }
 
   virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     return Representation::None();
   }
 
   DECLARE_CONCRETE_INSTRUCTION(OsrEntry)
 
  private:
   explicit HOsrEntry(BailoutId ast_id) : ast_id_(ast_id) {
-    SetGVNFlag(kChangesOsrEntries);
-    SetGVNFlag(kChangesNewSpacePromotion);
+    SetChangesFlag(kOsrEntries);
+    SetChangesFlag(kNewSpacePromotion);
   }
 
   BailoutId ast_id_;
 };
 
 
 class HParameter V8_FINAL : public HTemplateInstruction<0> {
  public:
   enum ParameterKind {
     STACK_PARAMETER,
@@ skipping 121 matching lines @@
  protected:
   virtual bool DataEquals(HValue* other) V8_OVERRIDE {
     return cell_ == HLoadGlobalCell::cast(other)->cell_;
   }
 
  private:
   HLoadGlobalCell(Handle<Cell> cell, PropertyDetails details)
     : cell_(Unique<Cell>::CreateUninitialized(cell)), details_(details) {
     set_representation(Representation::Tagged());
     SetFlag(kUseGVN);
-    SetGVNFlag(kDependsOnGlobalVars);
+    SetDependsOnFlag(kGlobalVars);
   }
 
   virtual bool IsDeletable() const V8_OVERRIDE { return !RequiresHoleCheck(); }
 
   Unique<Cell> cell_;
   PropertyDetails details_;
 };
 
 
 class HLoadGlobalGeneric V8_FINAL : public HTemplateInstruction<2> {
@@ skipping 131 matching lines @@
             Handle<AllocationSite> allocation_site =
                 Handle<AllocationSite>::null())
       : HTemplateInstruction<2>(type),
         flags_(ComputeFlags(pretenure_flag, instance_type)),
         dominating_allocate_(NULL),
         filler_free_space_size_(NULL) {
     SetOperandAt(0, context);
     SetOperandAt(1, size);
     set_representation(Representation::Tagged());
     SetFlag(kTrackSideEffectDominators);
-    SetGVNFlag(kChangesNewSpacePromotion);
-    SetGVNFlag(kDependsOnNewSpacePromotion);
+    SetChangesFlag(kNewSpacePromotion);
+    SetDependsOnFlag(kNewSpacePromotion);
 
     if (FLAG_trace_pretenuring) {
       PrintF("HAllocate with AllocationSite %p %s\n",
              allocation_site.is_null()
                  ? static_cast<void*>(NULL)
                  : static_cast<void*>(*allocation_site),
              pretenure_flag == TENURED ? "tenured" : "not tenured");
     }
   }
 
@@ skipping 177 matching lines @@
 
   DECLARE_CONCRETE_INSTRUCTION(StoreGlobalCell)
 
  private:
   HStoreGlobalCell(HValue* value,
                    Handle<PropertyCell> cell,
                    PropertyDetails details)
       : HUnaryOperation(value),
         cell_(Unique<PropertyCell>::CreateUninitialized(cell)),
         details_(details) {
-    SetGVNFlag(kChangesGlobalVars);
+    SetChangesFlag(kGlobalVars);
   }
 
   Unique<PropertyCell> cell_;
   PropertyDetails details_;
 };
 
 
 class HLoadContextSlot V8_FINAL : public HUnaryOperation {
  public:
   enum Mode {
@@ skipping 18 matching lines @@
         mode_ = kCheckDeoptimize;
         break;
       case CONST:
         mode_ = kCheckReturnUndefined;
         break;
       default:
         mode_ = kNoCheck;
     }
     set_representation(Representation::Tagged());
     SetFlag(kUseGVN);
-    SetGVNFlag(kDependsOnContextSlots);
+    SetDependsOnFlag(kContextSlots);
   }
 
   int slot_index() const { return slot_index_; }
   Mode mode() const { return mode_; }
 
   bool DeoptimizesOnHole() {
     return mode_ == kCheckDeoptimize;
   }
 
   bool RequiresHoleCheck() const {
@@ skipping 63 matching lines @@
 
   virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
   DECLARE_CONCRETE_INSTRUCTION(StoreContextSlot)
 
  private:
   HStoreContextSlot(HValue* context, int slot_index, Mode mode, HValue* value)
       : slot_index_(slot_index), mode_(mode) {
     SetOperandAt(0, context);
     SetOperandAt(1, value);
-    SetGVNFlag(kChangesContextSlots);
+    SetChangesFlag(kContextSlots);
   }
 
   int slot_index_;
   Mode mode_;
 };
 
 
 // Represents an access to a portion of an object, such as the map pointer,
 // array elements pointer, etc, but not accesses to array elements themselves.
 class HObjectAccess V8_FINAL {
@@ skipping 257 matching lines @@
 
   static HObjectAccess ForJSArrayBufferViewByteLength() {
     return HObjectAccess::ForObservableJSObjectOffset(
         JSArrayBufferView::kByteLengthOffset);
   }
 
   static HObjectAccess ForGlobalObjectNativeContext() {
     return HObjectAccess(kInobject, GlobalObject::kNativeContextOffset);
   }
 
-  void PrintTo(StringStream* stream);
+  void PrintTo(StringStream* stream) const;
 
   inline bool Equals(HObjectAccess that) const {
     return value_ == that.value_;  // portion and offset must match
   }
 
  protected:
   void SetGVNFlags(HValue *instr, PropertyAccessType access_type);
 
  private:
   // internal use only; different parts of an object or array
   enum Portion {
     kMaps,             // map of an object
     kArrayLengths,     // the length of an array
     kStringLengths,    // the length of a string
     kElementsPointer,  // elements pointer
     kBackingStore,     // some field in the backing store
     kDouble,           // some double field
     kInobject,         // some other in-object field
     kExternalMemory    // some field in external memory
   };
 
+  HObjectAccess() : value_(0) {}
+
   HObjectAccess(Portion portion, int offset,
                 Representation representation = Representation::Tagged(),
                 Handle<String> name = Handle<String>::null(),
                 bool immutable = false,
                 bool existing_inobject_property = true)
     : value_(PortionField::encode(portion) |
              RepresentationField::encode(representation.kind()) |
              ImmutableField::encode(immutable ? 1 : 0) |
              ExistingInobjectPropertyField::encode(
                  existing_inobject_property ? 1 : 0) |
@@ skipping 12 matching lines @@
   class RepresentationField : public BitField<Representation::Kind, 3, 4> {};
   class ImmutableField : public BitField<bool, 7, 1> {};
   class ExistingInobjectPropertyField : public BitField<bool, 8, 1> {};
   class OffsetField : public BitField<int, 9, 23> {};
 
   uint32_t value_;  // encodes portion, representation, immutable, and offset
   Handle<String> name_;
 
   friend class HLoadNamedField;
   friend class HStoreNamedField;
+  friend class SideEffectsScope;
 
   inline Portion portion() const {
     return PortionField::decode(value_);
   }
 };
 
 
 class HLoadNamedField V8_FINAL : public HTemplateInstruction<2> {
  public:
   DECLARE_INSTRUCTION_FACTORY_P3(HLoadNamedField, HValue*, HValue*,
@@ skipping 116 matching lines @@
   DECLARE_CONCRETE_INSTRUCTION(LoadFunctionPrototype)
 
  protected:
   virtual bool DataEquals(HValue* other) V8_OVERRIDE { return true; }
 
  private:
   explicit HLoadFunctionPrototype(HValue* function)
       : HUnaryOperation(function) {
     set_representation(Representation::Tagged());
     SetFlag(kUseGVN);
-    SetGVNFlag(kDependsOnCalls);
+    SetDependsOnFlag(kCalls);
   }
 };
 
 class ArrayInstructionInterface {
  public:
   virtual HValue* GetKey() = 0;
   virtual void SetKey(HValue* key) = 0;
   virtual void SetIndexOffset(uint32_t index_offset) = 0;
   virtual int MaxIndexOffsetBits() = 0;
   virtual bool IsDehoisted() = 0;
@@ skipping 124 matching lines @@
           set_type(HType::Smi());
           if (SmiValuesAre32Bits() && !RequiresHoleCheck()) {
             set_representation(Representation::Integer32());
           } else {
             set_representation(Representation::Smi());
           }
         } else {
           set_representation(Representation::Tagged());
         }
 
-        SetGVNFlag(kDependsOnArrayElements);
+        SetDependsOnFlag(kArrayElements);
       } else {
         set_representation(Representation::Double());
-        SetGVNFlag(kDependsOnDoubleArrayElements);
+        SetDependsOnFlag(kDoubleArrayElements);
       }
     } else {
       if (elements_kind == EXTERNAL_FLOAT32_ELEMENTS ||
           elements_kind == EXTERNAL_FLOAT64_ELEMENTS ||
           elements_kind == FLOAT32_ELEMENTS ||
           elements_kind == FLOAT64_ELEMENTS) {
         set_representation(Representation::Double());
       } else {
         set_representation(Representation::Integer32());
       }
 
       if (is_external()) {
-        SetGVNFlag(kDependsOnExternalMemory);
+        SetDependsOnFlag(kExternalMemory);
       } else if (is_fixed_typed_array()) {
-        SetGVNFlag(kDependsOnTypedArrayElements);
+        SetDependsOnFlag(kTypedArrayElements);
       } else {
         UNREACHABLE();
       }
       // Native code could change the specialized array.
-      SetGVNFlag(kDependsOnCalls);
+      SetDependsOnFlag(kCalls);
     }
 
     SetFlag(kUseGVN);
   }
 
   virtual bool IsDeletable() const V8_OVERRIDE {
     return !RequiresHoleCheck();
   }
 
   // Establish some checks around our packed fields
@@ skipping 103 matching lines @@
         }
         return field_representation();
       } else if (field_representation().IsExternal()) {
         return Representation::External();
       }
     }
     return Representation::Tagged();
   }
   virtual bool HandleSideEffectDominator(GVNFlag side_effect,
                                          HValue* dominator) V8_OVERRIDE {
-    ASSERT(side_effect == kChangesNewSpacePromotion);
+    ASSERT(side_effect == kNewSpacePromotion);
     new_space_dominator_ = dominator;
     return false;
   }
   virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
   void SkipWriteBarrier() { write_barrier_mode_ = SKIP_WRITE_BARRIER; }
   bool IsSkipWriteBarrier() const {
     return write_barrier_mode_ == SKIP_WRITE_BARRIER;
   }
 
@@ skipping 211 matching lines @@
   void SetUninitialized(bool is_uninitialized) {
     is_uninitialized_ = is_uninitialized;
   }
 
   bool IsConstantHoleStore() {
     return value()->IsConstant() && HConstant::cast(value())->IsTheHole();
   }
 
   virtual bool HandleSideEffectDominator(GVNFlag side_effect,
                                          HValue* dominator) V8_OVERRIDE {
-    ASSERT(side_effect == kChangesNewSpacePromotion);
+    ASSERT(side_effect == kNewSpacePromotion);
     new_space_dominator_ = dominator;
     return false;
   }
 
   HValue* new_space_dominator() const { return new_space_dominator_; }
 
   bool NeedsWriteBarrier() {
     if (value_is_smi()) {
       return false;
     } else {
@@ skipping 22 matching lines @@
     if (!FLAG_smi_x64_store_opt) store_mode_ = INITIALIZING_STORE;
     SetOperandAt(0, obj);
     SetOperandAt(1, key);
     SetOperandAt(2, val);
 
     ASSERT(store_mode != STORE_TO_INITIALIZED_ENTRY ||
            elements_kind == FAST_SMI_ELEMENTS);
 
     if (IsFastObjectElementsKind(elements_kind)) {
       SetFlag(kTrackSideEffectDominators);
-      SetGVNFlag(kDependsOnNewSpacePromotion);
+      SetDependsOnFlag(kNewSpacePromotion);
     }
     if (is_external()) {
-      SetGVNFlag(kChangesExternalMemory);
+      SetChangesFlag(kExternalMemory);
       SetFlag(kAllowUndefinedAsNaN);
     } else if (IsFastDoubleElementsKind(elements_kind)) {
-      SetGVNFlag(kChangesDoubleArrayElements);
+      SetChangesFlag(kDoubleArrayElements);
     } else if (IsFastSmiElementsKind(elements_kind)) {
-      SetGVNFlag(kChangesArrayElements);
+      SetChangesFlag(kArrayElements);
     } else if (is_fixed_typed_array()) {
-      SetGVNFlag(kChangesTypedArrayElements);
+      SetChangesFlag(kTypedArrayElements);
       SetFlag(kAllowUndefinedAsNaN);
     } else {
-      SetGVNFlag(kChangesArrayElements);
+      SetChangesFlag(kArrayElements);
     }
 
     // EXTERNAL_{UNSIGNED_,}{BYTE,SHORT,INT}_ELEMENTS are truncating.
     if ((elements_kind >= EXTERNAL_INT8_ELEMENTS &&
         elements_kind <= EXTERNAL_UINT32_ELEMENTS) ||
         (elements_kind >= UINT8_ELEMENTS &&
         elements_kind <= INT32_ELEMENTS)) {
       SetFlag(kTruncatingToInt32);
     }
   }
@@ skipping 83 matching lines @@
                           HValue* object,
                           Handle<Map> original_map,
                           Handle<Map> transitioned_map)
       : original_map_(Unique<Map>(original_map)),
         transitioned_map_(Unique<Map>(transitioned_map)),
         from_kind_(original_map->elements_kind()),
         to_kind_(transitioned_map->elements_kind()) {
     SetOperandAt(0, object);
     SetOperandAt(1, context);
     SetFlag(kUseGVN);
-    SetGVNFlag(kChangesElementsKind);
+    SetChangesFlag(kElementsKind);
     if (!IsSimpleMapChangeTransition(from_kind_, to_kind_)) {
-      SetGVNFlag(kChangesElementsPointer);
-      SetGVNFlag(kChangesNewSpacePromotion);
+      SetChangesFlag(kElementsPointer);
+      SetChangesFlag(kNewSpacePromotion);
     }
     set_representation(Representation::Tagged());
   }
 
   Unique<Map> original_map_;
   Unique<Map> transitioned_map_;
   ElementsKind from_kind_;
   ElementsKind to_kind_;
 };
 
@@ skipping 30 matching lines @@
   HStringAdd(HValue* context,
              HValue* left,
              HValue* right,
              PretenureFlag pretenure_flag,
              StringAddFlags flags,
              Handle<AllocationSite> allocation_site)
       : HBinaryOperation(context, left, right, HType::String()),
         flags_(flags), pretenure_flag_(pretenure_flag) {
     set_representation(Representation::Tagged());
     SetFlag(kUseGVN);
-    SetGVNFlag(kDependsOnMaps);
-    SetGVNFlag(kChangesNewSpacePromotion);
+    SetDependsOnFlag(kMaps);
+    SetChangesFlag(kNewSpacePromotion);
     if (FLAG_trace_pretenuring) {
       PrintF("HStringAdd with AllocationSite %p %s\n",
              allocation_site.is_null()
                  ? static_cast<void*>(NULL)
                  : static_cast<void*>(*allocation_site),
              pretenure_flag == TENURED ? "tenured" : "not tenured");
     }
   }
 
   // No side-effects except possible allocation:
@@ skipping 30 matching lines @@
     return new(zone) Range(0, String::kMaxUtf16CodeUnit);
   }
 
  private:
   HStringCharCodeAt(HValue* context, HValue* string, HValue* index) {
     SetOperandAt(0, context);
     SetOperandAt(1, string);
     SetOperandAt(2, index);
     set_representation(Representation::Integer32());
     SetFlag(kUseGVN);
-    SetGVNFlag(kDependsOnMaps);
-    SetGVNFlag(kDependsOnStringChars);
-    SetGVNFlag(kChangesNewSpacePromotion);
+    SetDependsOnFlag(kMaps);
+    SetDependsOnFlag(kStringChars);
+    SetChangesFlag(kNewSpacePromotion);
   }
 
   // No side effects: runtime function assumes string + number inputs.
   virtual bool IsDeletable() const V8_OVERRIDE { return true; }
 };
 
 
 class HStringCharFromCode V8_FINAL : public HTemplateInstruction<2> {
  public:
   static HInstruction* New(Zone* zone,
@@ skipping 13 matching lines @@
 
   DECLARE_CONCRETE_INSTRUCTION(StringCharFromCode)
 
  private:
   HStringCharFromCode(HValue* context, HValue* char_code)
       : HTemplateInstruction<2>(HType::String()) {
     SetOperandAt(0, context);
     SetOperandAt(1, char_code);
     set_representation(Representation::Tagged());
     SetFlag(kUseGVN);
-    SetGVNFlag(kChangesNewSpacePromotion);
+    SetChangesFlag(kNewSpacePromotion);
   }
 
   virtual bool IsDeletable() const V8_OVERRIDE {
     return !value()->ToNumberCanBeObserved();
   }
 };
 
 
 template <int V>
 class HMaterializedLiteral : public HTemplateInstruction<V> {
@@ skipping 88 matching lines @@
                    Handle<SharedFunctionInfo> shared,
                    bool pretenure)
       : HTemplateInstruction<1>(HType::JSObject()),
         shared_info_(shared),
         pretenure_(pretenure),
         has_no_literals_(shared->num_literals() == 0),
         is_generator_(shared->is_generator()),
         language_mode_(shared->language_mode()) {
     SetOperandAt(0, context);
     set_representation(Representation::Tagged());
-    SetGVNFlag(kChangesNewSpacePromotion);
+    SetChangesFlag(kNewSpacePromotion);
   }
 
   virtual bool IsDeletable() const V8_OVERRIDE { return true; }
 
   Handle<SharedFunctionInfo> shared_info_;
   bool pretenure_ : 1;
   bool has_no_literals_ : 1;
   bool is_generator_ : 1;
   LanguageMode language_mode_;
 };
@@ skipping 50 matching lines @@
 
   virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     return Representation::Tagged();
   }
 
   DECLARE_CONCRETE_INSTRUCTION(ToFastProperties)
 
  private:
   explicit HToFastProperties(HValue* value) : HUnaryOperation(value) {
     set_representation(Representation::Tagged());
-    SetGVNFlag(kChangesNewSpacePromotion);
+    SetChangesFlag(kNewSpacePromotion);
 
     // This instruction is not marked as kChangesMaps, but does
     // change the map of the input operand. Use it only when creating
     // object literals via a runtime call.
     ASSERT(value->IsCallRuntime());
 #ifdef DEBUG
     const Runtime::Function* function = HCallRuntime::cast(value)->function();
     ASSERT(function->function_id == Runtime::kCreateObjectLiteral);
 #endif
   }
@@ skipping 58 matching lines @@
   }
 
  private:
   HSeqStringGetChar(String::Encoding encoding,
                     HValue* string,
                     HValue* index) : encoding_(encoding) {
     SetOperandAt(0, string);
     SetOperandAt(1, index);
     set_representation(Representation::Integer32());
     SetFlag(kUseGVN);
-    SetGVNFlag(kDependsOnStringChars);
+    SetDependsOnFlag(kStringChars);
   }
 
   virtual bool IsDeletable() const V8_OVERRIDE { return true; }
 
   String::Encoding encoding_;
 };
 
 
 class HSeqStringSetChar V8_FINAL : public HTemplateInstruction<4> {
  public:
@@ skipping 18 matching lines @@
   HSeqStringSetChar(HValue* context,
                     String::Encoding encoding,
                     HValue* string,
                     HValue* index,
                     HValue* value) : encoding_(encoding) {
     SetOperandAt(0, context);
     SetOperandAt(1, string);
     SetOperandAt(2, index);
     SetOperandAt(3, value);
     set_representation(Representation::Tagged());
-    SetGVNFlag(kChangesStringChars);
+    SetChangesFlag(kStringChars);
   }
 
   String::Encoding encoding_;
 };
 
 
 class HCheckMapValue V8_FINAL : public HTemplateInstruction<2> {
  public:
   DECLARE_INSTRUCTION_FACTORY_P2(HCheckMapValue, HValue*, HValue*);
 
@@ skipping 19 matching lines @@
     return true;
   }
 
  private:
   HCheckMapValue(HValue* value,
                  HValue* map) {
     SetOperandAt(0, value);
     SetOperandAt(1, map);
     set_representation(Representation::Tagged());
     SetFlag(kUseGVN);
-    SetGVNFlag(kDependsOnMaps);
-    SetGVNFlag(kDependsOnElementsKind);
+    SetDependsOnFlag(kMaps);
+    SetDependsOnFlag(kElementsKind);
   }
 };
 
 
 class HForInPrepareMap V8_FINAL : public HTemplateInstruction<2> {
  public:
   DECLARE_INSTRUCTION_WITH_CONTEXT_FACTORY_P1(HForInPrepareMap, HValue*);
 
   virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     return Representation::Tagged();
@@ skipping 91 matching lines @@
   virtual bool IsDeletable() const V8_OVERRIDE { return true; }
 };
 
 
 #undef DECLARE_INSTRUCTION
 #undef DECLARE_CONCRETE_INSTRUCTION
 
 } }  // namespace v8::internal
 
 #endif  // V8_HYDROGEN_INSTRUCTIONS_H_