Remove relocation lock.

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 216 matching lines @@
 
 #define DECLARE_CONCRETE_INSTRUCTION(type)                        \
   virtual LInstruction* CompileToLithium(LChunkBuilder* builder); \
   static H##type* cast(HValue* value) {                           \
     ASSERT(value->Is##type());                                    \
     return reinterpret_cast<H##type*>(value);                     \
   }                                                               \
   virtual Opcode opcode() const { return HValue::k##type; }
 
 
-#ifdef DEBUG
-#define ASSERT_ALLOCATION_DISABLED                                       \
-  ASSERT(isolate()->optimizing_compiler_thread()->IsOptimizerThread() || \
-         !isolate()->heap()->IsAllocationAllowed())
-#else
-#define ASSERT_ALLOCATION_DISABLED do {} while (0)
-#endif
-
 class Range: public ZoneObject {
  public:
   Range()
       : lower_(kMinInt),
         upper_(kMaxInt),
         next_(NULL),
         can_be_minus_zero_(false) { }
 
   Range(int32_t lower, int32_t upper)
       : lower_(lower),
@@ skipping 102 matching lines @@
  private:
   explicit Representation(Kind k) : kind_(k) { }
 
   // Make sure kind fits in int8.
   STATIC_ASSERT(kNumRepresentations <= (1 << kBitsPerByte));
 
   int8_t kind_;
 };
 
 
+class UniqueValueId {
+ public:
+  UniqueValueId() : raw_address_(NULL) { }
+
+  explicit UniqueValueId(Object* object) {
+    raw_address_ = reinterpret_cast<Address>(object);
+    ASSERT(!IsUninitialized());
+  }
+
+  explicit UniqueValueId(Handle<Object> handle) {
+    static const Address kEmptyHandleSentinel = reinterpret_cast<Address>(1);
+    if (handle.is_null()) {
+      raw_address_ = kEmptyHandleSentinel;
+    } else {
+      raw_address_ = reinterpret_cast<Address>(*handle);
+      ASSERT_NE(kEmptyHandleSentinel, raw_address_);
+    }
+    ASSERT(!IsUninitialized());
+  }
+
+  bool IsUninitialized() const { return raw_address_ == NULL; }
+
+  bool operator==(const UniqueValueId& other) const {
+    ASSERT(!IsUninitialized() && !other.IsUninitialized());
+    return raw_address_ == other.raw_address_;
+  }
+
+  bool operator!=(const UniqueValueId& other) const {
+    ASSERT(!IsUninitialized() && !other.IsUninitialized());
+    return raw_address_ != other.raw_address_;
+  }
+
+  intptr_t Hashcode() const {
+    ASSERT(!IsUninitialized());
+    return reinterpret_cast<intptr_t>(raw_address_);
+  }
+
+  bool IsImmovableObject(Object* object) const {

[Sven Panne, 2013/04/16 09:46:42]

Slightly obscure, and we don't need this (see below).

[Yang, 2013/04/16 09:59:06]

Done.

+    // The raw address does not change for immovable objects.
+    ASSERT(!IsUninitialized());
+    return reinterpret_cast<Address>(object) == raw_address_;
+  }
+
+ private:
+  Address raw_address_;
+};
+
+
 class HType {
  public:
   HType() : type_(kUninitialized) { }
 
   static HType Tagged() { return HType(kTagged); }
   static HType TaggedPrimitive() { return HType(kTaggedPrimitive); }
   static HType TaggedNumber() { return HType(kTaggedNumber); }
   static HType Smi() { return HType(kSmi); }
   static HType HeapNumber() { return HType(kHeapNumber); }
   static HType String() { return HType(kString); }
@@ skipping 673 matching lines @@
 
   // This gives the instruction an opportunity to replace itself with an
   // instruction that does the same in some better way.  To replace an
   // instruction with a new one, first add the new instruction to the graph,
   // then return it.  Return NULL to have the instruction deleted.
   virtual HValue* Canonicalize() { return this; }
 
   bool Equals(HValue* other);
   virtual intptr_t Hashcode();
 
+  // Some instructions' hash code is dependent on object addresses and are not

[Sven Panne, 2013/04/16 09:46:42]

Adapt comment: We are talking about unique IDs here, not only hash codes.

[Yang, 2013/04/16 09:59:06]

Done.

+  // safe regarding GC and parallel recompilation.  Compute the hash upfront.
+  virtual void FinalizeUniqueValueId() { }
+
   // Printing support.
   virtual void PrintTo(StringStream* stream) = 0;
   void PrintNameTo(StringStream* stream);
   void PrintTypeTo(StringStream* stream);
   void PrintRangeTo(StringStream* stream);
   void PrintChangesTo(StringStream* stream);
 
   const char* Mnemonic() const;
 
   // Type information helpers.
@@ skipping 1566 matching lines @@
   virtual bool DataEquals(HValue* other) { return true; }
 
  private:
   virtual bool IsDeletable() const { return true; }
 };
 
 
 class HCheckMaps: public HTemplateInstruction<2> {
  public:
   HCheckMaps(HValue* value, Handle<Map> map, Zone* zone,
-             HValue* typecheck = NULL) {
+             HValue* typecheck = NULL)
+      : map_unique_ids_(0, zone) {
     SetOperandAt(0, value);
     // If callers don't depend on a typecheck, they can pass in NULL. In that
     // case we use a copy of the |value| argument as a dummy value.
     SetOperandAt(1, typecheck != NULL ? typecheck : value);
     set_representation(Representation::Tagged());
     SetFlag(kUseGVN);
     SetFlag(kTrackSideEffectDominators);
     SetGVNFlag(kDependsOnMaps);
     SetGVNFlag(kDependsOnElementsKind);
     map_set()->Add(map, zone);
   }
-  HCheckMaps(HValue* value, SmallMapList* maps, Zone* zone) {
+  HCheckMaps(HValue* value, SmallMapList* maps, Zone* zone)
+      : map_unique_ids_(0, zone) {
     SetOperandAt(0, value);
     SetOperandAt(1, value);
     set_representation(Representation::Tagged());
     SetFlag(kUseGVN);
     SetFlag(kTrackSideEffectDominators);
     SetGVNFlag(kDependsOnMaps);
     SetGVNFlag(kDependsOnElementsKind);
     for (int i = 0; i < maps->length(); i++) {
       map_set()->Add(maps->at(i), zone);
     }
@@ skipping 26 matching lines @@
   virtual Representation RequiredInputRepresentation(int index) {
     return Representation::Tagged();
   }
   virtual void SetSideEffectDominator(GVNFlag side_effect, HValue* dominator);
   virtual void PrintDataTo(StringStream* stream);
   virtual HType CalculateInferredType();
 
   HValue* value() { return OperandAt(0); }
   SmallMapList* map_set() { return &map_set_; }
 
+  virtual void FinalizeUniqueValueId();
+
   DECLARE_CONCRETE_INSTRUCTION(CheckMaps)
 
  protected:
   virtual bool DataEquals(HValue* other) {
+    ASSERT_EQ(map_set_.length(), map_unique_ids_.length());
     HCheckMaps* b = HCheckMaps::cast(other);
     // Relies on the fact that map_set has been sorted before.
-    if (map_set()->length() != b->map_set()->length()) return false;
-    for (int i = 0; i < map_set()->length(); i++) {
-      if (!map_set()->at(i).is_identical_to(b->map_set()->at(i))) return false;
+    if (map_unique_ids_.length() != b->map_unique_ids_.length()) {
+      return false;
+    }
+    for (int i = 0; i < map_unique_ids_.length(); i++) {
+      if (map_unique_ids_.at(i) != b->map_unique_ids_.at(i)) {
+        return false;
+      }
     }
     return true;
   }
 
  private:
   SmallMapList map_set_;
+  ZoneList<UniqueValueId> map_unique_ids_;
 };
 
 
 class HCheckFunction: public HUnaryOperation {
  public:
   HCheckFunction(HValue* value, Handle<JSFunction> function)
-      : HUnaryOperation(value), target_(function) {
+      : HUnaryOperation(value), target_(function), target_unique_id_() {
     set_representation(Representation::Tagged());
     SetFlag(kUseGVN);
     target_in_new_space_ = Isolate::Current()->heap()->InNewSpace(*function);
   }
 
   virtual Representation RequiredInputRepresentation(int index) {
     return Representation::Tagged();
   }
   virtual void PrintDataTo(StringStream* stream);
   virtual HType CalculateInferredType();
 
 #ifdef DEBUG
   virtual void Verify();
 #endif
 
+  virtual void FinalizeUniqueValueId() {
+    target_unique_id_ = UniqueValueId(target_);
+  }
+
   Handle<JSFunction> target() const { return target_; }
   bool target_in_new_space() const { return target_in_new_space_; }
 
   DECLARE_CONCRETE_INSTRUCTION(CheckFunction)
 
  protected:
   virtual bool DataEquals(HValue* other) {
     HCheckFunction* b = HCheckFunction::cast(other);
-    return target_.is_identical_to(b->target());
+    return target_unique_id_ == b->target_unique_id_;
   }
 
  private:
   Handle<JSFunction> target_;
+  UniqueValueId target_unique_id_;
   bool target_in_new_space_;
 };
 
 
 class HCheckInstanceType: public HUnaryOperation {
  public:
   static HCheckInstanceType* NewIsSpecObject(HValue* value, Zone* zone) {
     return new(zone) HCheckInstanceType(value, IS_SPEC_OBJECT);
   }
   static HCheckInstanceType* NewIsJSArray(HValue* value, Zone* zone) {
@@ skipping 84 matching lines @@
 
  protected:
   virtual bool DataEquals(HValue* other) { return true; }
 };
 
 
 class HCheckPrototypeMaps: public HTemplateInstruction<0> {
  public:
   HCheckPrototypeMaps(Handle<JSObject> prototype,
                       Handle<JSObject> holder,
-                      Zone* zone) : prototypes_(2, zone), maps_(2, zone) {
+                      Zone* zone)
+      : prototypes_(2, zone),
+        maps_(2, zone),
+        first_prototype_unique_id_(),
+        last_prototype_unique_id_() {
     SetFlag(kUseGVN);
     SetGVNFlag(kDependsOnMaps);
     // Keep a list of all objects on the prototype chain up to the holder
     // and the expected maps.
     while (true) {
       prototypes_.Add(prototype, zone);
       maps_.Add(Handle<Map>(prototype->map()), zone);
       if (prototype.is_identical_to(holder)) break;
       prototype = Handle<JSObject>(JSObject::cast(prototype->GetPrototype()));
     }
   }
 
   ZoneList<Handle<JSObject> >* prototypes() { return &prototypes_; }
 
   ZoneList<Handle<Map> >* maps() { return &maps_; }
 
   DECLARE_CONCRETE_INSTRUCTION(CheckPrototypeMaps)
 
   virtual Representation RequiredInputRepresentation(int index) {
     return Representation::None();
   }
 
   virtual void PrintDataTo(StringStream* stream);
 
   virtual intptr_t Hashcode() {
-    ASSERT_ALLOCATION_DISABLED;
-    // Dereferencing to use the object's raw address for hashing is safe.
-    HandleDereferenceGuard allow_handle_deref(isolate(),
-                                              HandleDereferenceGuard::ALLOW);
-    SLOW_ASSERT(Heap::RelocationLock::IsLocked(isolate()->heap()) ||
-                !isolate()->optimizing_compiler_thread()->IsOptimizerThread());
-    intptr_t hash = 0;
-    for (int i = 0; i < prototypes_.length(); i++) {
-      hash = 17 * hash + reinterpret_cast<intptr_t>(*prototypes_[i]);
-      hash = 17 * hash + reinterpret_cast<intptr_t>(*maps_[i]);
-    }
-    return hash;
+    return first_prototype_unique_id_.Hashcode() * 17 +
+           last_prototype_unique_id_.Hashcode();
+  }
+
+  virtual void FinalizeUniqueValueId() {
+    first_prototype_unique_id_ = UniqueValueId(prototypes_.first());
+    last_prototype_unique_id_ = UniqueValueId(prototypes_.last());
   }
 
   bool CanOmitPrototypeChecks() {
     for (int i = 0; i < maps()->length(); i++) {
       if (!maps()->at(i)->CanOmitPrototypeChecks()) return false;
     }
     return true;
   }
 
  protected:
   virtual bool DataEquals(HValue* other) {
     HCheckPrototypeMaps* b = HCheckPrototypeMaps::cast(other);
-#ifdef DEBUG
-    if (prototypes_.length() != b->prototypes()->length()) return false;
-    for (int i = 0; i < prototypes_.length(); i++) {
-      if (!prototypes_[i].is_identical_to(b->prototypes()->at(i))) return false;
-      if (!maps_[i].is_identical_to(b->maps()->at(i))) return false;
-    }
-    return true;
-#else
-    return prototypes_.first().is_identical_to(b->prototypes()->first()) &&
-           prototypes_.last().is_identical_to(b->prototypes()->last());
-#endif  // DEBUG
+    return first_prototype_unique_id_ == b->first_prototype_unique_id_ &&
+           last_prototype_unique_id_ == b->last_prototype_unique_id_;
   }
 
  private:
   ZoneList<Handle<JSObject> > prototypes_;
   ZoneList<Handle<Map> > maps_;
+  UniqueValueId first_prototype_unique_id_;
+  UniqueValueId last_prototype_unique_id_;
 };
 
 
 class HCheckSmi: public HUnaryOperation {
  public:
   explicit HCheckSmi(HValue* value) : HUnaryOperation(value) {
     set_representation(Representation::Tagged());
     SetFlag(kUseGVN);
   }
 
@@ skipping 234 matching lines @@
 class HConstant: public HTemplateInstruction<0> {
  public:
   HConstant(Handle<Object> handle, Representation r);
   HConstant(int32_t value,
             Representation r,
             Handle<Object> optional_handle = Handle<Object>::null());
   HConstant(double value,
             Representation r,
             Handle<Object> optional_handle = Handle<Object>::null());
   HConstant(Handle<Object> handle,
+            UniqueValueId unique_id,
             Representation r,
             HType type,
             bool is_internalized_string,
             bool boolean_value);
 
   Handle<Object> handle() {
     if (handle_.is_null()) {
       handle_ = FACTORY->NewNumber(double_value_, TENURED);
     }
     ASSERT(has_int32_value_ || !handle_->IsSmi());
     return handle_;
   }
 
-  bool InOldSpace() const { return !HEAP->InNewSpace(*handle_); }
-
   bool IsSpecialDouble() const {
     return has_double_value_ &&
         (BitCast<int64_t>(double_value_) == BitCast<int64_t>(-0.0) ||
          FixedDoubleArray::is_the_hole_nan(double_value_) ||
          isnan(double_value_));
   }
 
   bool ImmortalImmovable() const {
     if (has_int32_value_) {
       return false;
     }
     if (has_double_value_) {
       if (IsSpecialDouble()) {
         return true;
       }
       return false;
     }
 
     ASSERT(!handle_.is_null());
+    HandleDereferenceGuard allow_dereference_for_immovable_check(
+        isolate(), HandleDereferenceGuard::ALLOW);
     Heap* heap = isolate()->heap();
-    // We should have handled minus_zero_value and nan_value in the
-    // has_double_value_ clause above.
-    // Dereferencing is safe to compare against immovable singletons.
-    HandleDereferenceGuard allow_handle_deref(isolate(),
-                                              HandleDereferenceGuard::ALLOW);
-    ASSERT(*handle_ != heap->minus_zero_value());
-    ASSERT(*handle_ != heap->nan_value());
-    return *handle_ == heap->undefined_value() ||
-           *handle_ == heap->null_value() ||
-           *handle_ == heap->true_value() ||
-           *handle_ == heap->false_value() ||
-           *handle_ == heap->the_hole_value() ||
-           *handle_ == heap->empty_string();
+    ASSERT(!unique_id_.IsImmovableObject(heap->minus_zero_value()));

[Sven Panne, 2013/04/16 09:46:42]

Just construct a UniqueValueId for the RHS and use == or != here and below, it
is compiled away anyway.

[Yang, 2013/04/16 09:59:06]

Done.

+    ASSERT(!unique_id_.IsImmovableObject(heap->nan_value()));
+    return unique_id_.IsImmovableObject(heap->undefined_value()) ||
+           unique_id_.IsImmovableObject(heap->null_value()) ||
+           unique_id_.IsImmovableObject(heap->true_value()) ||
+           unique_id_.IsImmovableObject(heap->false_value()) ||
+           unique_id_.IsImmovableObject(heap->the_hole_value()) ||
+           unique_id_.IsImmovableObject(heap->empty_string());
   }
 
   virtual Representation RequiredInputRepresentation(int index) {
     return Representation::None();
   }
 
   virtual bool IsConvertibleToInteger() const {
     return has_int32_value_;
   }
 
@@ skipping 49 matching lines @@
     return HasStringValue() && is_internalized_string_;
   }
 
   bool BooleanValue() const { return boolean_value_; }
 
   bool IsUint32() {
     return HasInteger32Value() && (Integer32Value() >= 0);
   }
 
   virtual intptr_t Hashcode() {
-    ASSERT_ALLOCATION_DISABLED;
-    intptr_t hash;
-
     if (has_int32_value_) {
-      hash = static_cast<intptr_t>(int32_value_);
+      return static_cast<intptr_t>(int32_value_);
     } else if (has_double_value_) {
-      hash = static_cast<intptr_t>(BitCast<int64_t>(double_value_));
+      return static_cast<intptr_t>(BitCast<int64_t>(double_value_));
     } else {
       ASSERT(!handle_.is_null());
-      // Dereferencing to use the object's raw address for hashing is safe.
-      HandleDereferenceGuard allow_handle_deref(isolate(),
-                                                HandleDereferenceGuard::ALLOW);
-      SLOW_ASSERT(Heap::RelocationLock::IsLocked(isolate()->heap()) ||
-                 !isolate()->optimizing_compiler_thread()->IsOptimizerThread());
-      hash = reinterpret_cast<intptr_t>(*handle_);
+      return unique_id_.Hashcode();
     }
+  }
 
-    return hash;
+  virtual void FinalizeUniqueValueId() {
+    if (!has_double_value_) {
+      ASSERT(!handle_.is_null());
+      unique_id_ = UniqueValueId(handle_);
+    }
   }
 
 #ifdef DEBUG
   virtual void Verify() { }
 #endif
 
   DECLARE_CONCRETE_INSTRUCTION(Constant)
 
  protected:
   virtual Range* InferRange(Zone* zone);
 
   virtual bool DataEquals(HValue* other) {
     HConstant* other_constant = HConstant::cast(other);
     if (has_int32_value_) {
       return other_constant->has_int32_value_ &&
           int32_value_ == other_constant->int32_value_;
     } else if (has_double_value_) {
       return other_constant->has_double_value_ &&
           BitCast<int64_t>(double_value_) ==
           BitCast<int64_t>(other_constant->double_value_);
     } else {
       ASSERT(!handle_.is_null());
       return !other_constant->handle_.is_null() &&
-          handle_.is_identical_to(other_constant->handle_);
+             unique_id_ == other_constant->unique_id_;
     }
   }
 
  private:
   void Initialize(Representation r);
 
   virtual bool IsDeletable() const { return true; }
 
   // If this is a numerical constant, handle_ either points to to the
   // HeapObject the constant originated from or is null.  If the
   // constant is non-numeric, handle_ always points to a valid
   // constant HeapObject.
   Handle<Object> handle_;
+  UniqueValueId unique_id_;
 
   // We store the HConstant in the most specific form safely possible.
   // The two flags, has_int32_value_ and has_double_value_ tell us if
   // int32_value_ and double_value_ hold valid, safe representations
   // of the constant.  has_int32_value_ implies has_double_value_ but
   // not the converse.
   bool has_int32_value_ : 1;
   bool has_double_value_ : 1;
   bool is_internalized_string_ : 1;  // TODO(yangguo): make this part of HType.
   bool boolean_value_ : 1;
@@ skipping 1391 matching lines @@
   DECLARE_CONCRETE_INSTRUCTION(UnknownOSRValue)
 
  private:
   HPhi* incoming_value_;
 };
 
 
 class HLoadGlobalCell: public HTemplateInstruction<0> {
  public:
   HLoadGlobalCell(Handle<JSGlobalPropertyCell> cell, PropertyDetails details)
-      : cell_(cell), details_(details) {
+      : cell_(cell), details_(details), unique_id_() {
     set_representation(Representation::Tagged());
     SetFlag(kUseGVN);
     SetGVNFlag(kDependsOnGlobalVars);
   }
 
   Handle<JSGlobalPropertyCell> cell() const { return cell_; }
   bool RequiresHoleCheck() const;
 
   virtual void PrintDataTo(StringStream* stream);
 
   virtual intptr_t Hashcode() {
-    ASSERT_ALLOCATION_DISABLED;
-    // Dereferencing to use the object's raw address for hashing is safe.
-    HandleDereferenceGuard allow_handle_deref(isolate(),
-                                              HandleDereferenceGuard::ALLOW);
-    SLOW_ASSERT(Heap::RelocationLock::IsLocked(isolate()->heap()) ||
-               !isolate()->optimizing_compiler_thread()->IsOptimizerThread());
-    return reinterpret_cast<intptr_t>(*cell_);
+    return unique_id_.Hashcode();
+  }
+
+  virtual void FinalizeUniqueValueId() {
+    unique_id_ = UniqueValueId(cell_);
   }
 
   virtual Representation RequiredInputRepresentation(int index) {
     return Representation::None();
   }
 
   DECLARE_CONCRETE_INSTRUCTION(LoadGlobalCell)
 
  protected:
   virtual bool DataEquals(HValue* other) {
     HLoadGlobalCell* b = HLoadGlobalCell::cast(other);
-    return cell_.is_identical_to(b->cell());
+    return unique_id_ == b->unique_id_;
   }
 
  private:
   virtual bool IsDeletable() const { return !RequiresHoleCheck(); }
 
   Handle<JSGlobalPropertyCell> cell_;
   PropertyDetails details_;
+  UniqueValueId unique_id_;
 };
 
 
 class HLoadGlobalGeneric: public HTemplateInstruction<2> {
  public:
   HLoadGlobalGeneric(HValue* context,
                      HValue* global_object,
                      Handle<Object> name,
                      bool for_typeof)
       : name_(name),
@@ skipping 439 matching lines @@
   virtual Representation RequiredInputRepresentation(int index) {
     return Representation::Tagged();
   }
 
   virtual void PrintDataTo(StringStream* stream);
 
   DECLARE_CONCRETE_INSTRUCTION(LoadNamedFieldPolymorphic)
 
   static const int kMaxLoadPolymorphism = 4;
 
+  virtual void FinalizeUniqueValueId();
+
  protected:
   virtual bool DataEquals(HValue* value);
 
  private:
   SmallMapList types_;
   Handle<String> name_;
+  ZoneList<UniqueValueId> types_unique_ids_;
+  UniqueValueId name_unique_id_;
   bool need_generic_;
 };
 
 
 
 class HLoadNamedGeneric: public HTemplateInstruction<2> {
  public:
   HLoadNamedGeneric(HValue* context, HValue* object, Handle<Object> name)
       : name_(name) {
     SetOperandAt(0, context);
@@ skipping 243 matching lines @@
 class HStoreNamedField: public HTemplateInstruction<2> {
  public:
   HStoreNamedField(HValue* obj,
                    Handle<String> name,
                    HValue* val,
                    bool in_object,
                    int offset)
       : name_(name),
         is_in_object_(in_object),
         offset_(offset),
+        transition_unique_id_(),
         new_space_dominator_(NULL) {
     SetOperandAt(0, obj);
     SetOperandAt(1, val);
     SetFlag(kTrackSideEffectDominators);
     SetGVNFlag(kDependsOnNewSpacePromotion);
     if (is_in_object_) {
       SetGVNFlag(kChangesInobjectFields);
     } else {
       SetGVNFlag(kChangesBackingStoreFields);
     }
@@ skipping 10 matching lines @@
   }
   virtual void PrintDataTo(StringStream* stream);
 
   HValue* object() { return OperandAt(0); }
   HValue* value() { return OperandAt(1); }
 
   Handle<String> name() const { return name_; }
   bool is_in_object() const { return is_in_object_; }
   int offset() const { return offset_; }
   Handle<Map> transition() const { return transition_; }
+  UniqueValueId transition_unique_id() const { return transition_unique_id_; }
   void set_transition(Handle<Map> map) { transition_ = map; }
   HValue* new_space_dominator() const { return new_space_dominator_; }
 
   bool NeedsWriteBarrier() {
     return StoringValueNeedsWriteBarrier(value()) &&
         ReceiverObjectNeedsWriteBarrier(object(), new_space_dominator());
   }
 
   bool NeedsWriteBarrierForMap() {
     return ReceiverObjectNeedsWriteBarrier(object(), new_space_dominator());
   }
 
+  virtual void FinalizeUniqueValueId() {
+    transition_unique_id_ = UniqueValueId(transition_);
+  }
+
  private:
   Handle<String> name_;
   bool is_in_object_;
   int offset_;
   Handle<Map> transition_;
+  UniqueValueId transition_unique_id_;
   HValue* new_space_dominator_;
 };
 
 
 class HStoreNamedGeneric: public HTemplateInstruction<3> {
  public:
   HStoreNamedGeneric(HValue* context,
                      HValue* object,
                      Handle<String> name,
                      HValue* value,
@@ skipping 180 matching lines @@
 
 
 class HTransitionElementsKind: public HTemplateInstruction<2> {
  public:
   HTransitionElementsKind(HValue* context,
                           HValue* object,
                           Handle<Map> original_map,
                           Handle<Map> transitioned_map)
       : original_map_(original_map),
         transitioned_map_(transitioned_map),
+        original_map_unique_id_(),
+        transitioned_map_unique_id_(),
         from_kind_(original_map->elements_kind()),
         to_kind_(transitioned_map->elements_kind()) {
     SetOperandAt(0, object);
     SetOperandAt(1, context);
     SetFlag(kUseGVN);
     SetGVNFlag(kChangesElementsKind);
     if (original_map->has_fast_double_elements()) {
       SetGVNFlag(kChangesElementsPointer);
       SetGVNFlag(kChangesNewSpacePromotion);
     }
@@ skipping 10 matching lines @@
 
   HValue* object() { return OperandAt(0); }
   HValue* context() { return OperandAt(1); }
   Handle<Map> original_map() { return original_map_; }
   Handle<Map> transitioned_map() { return transitioned_map_; }
   ElementsKind from_kind() { return from_kind_; }
   ElementsKind to_kind() { return to_kind_; }
 
   virtual void PrintDataTo(StringStream* stream);
 
+  virtual void FinalizeUniqueValueId() {
+    original_map_unique_id_ = UniqueValueId(original_map_);
+    transitioned_map_unique_id_ = UniqueValueId(transitioned_map_);
+  }
+
   DECLARE_CONCRETE_INSTRUCTION(TransitionElementsKind)
 
  protected:
   virtual bool DataEquals(HValue* other) {
     HTransitionElementsKind* instr = HTransitionElementsKind::cast(other);
-    return original_map_.is_identical_to(instr->original_map()) &&
-        transitioned_map_.is_identical_to(instr->transitioned_map());
+    return original_map_unique_id_ == instr->original_map_unique_id_ &&
+           transitioned_map_unique_id_ == instr->transitioned_map_unique_id_;
   }
 
  private:
   Handle<Map> original_map_;
   Handle<Map> transitioned_map_;
+  UniqueValueId original_map_unique_id_;
+  UniqueValueId transitioned_map_unique_id_;
   ElementsKind from_kind_;
   ElementsKind to_kind_;
 };
 
 
 class HStringAdd: public HBinaryOperation {
  public:
   static HInstruction* New(Zone* zone,
                            HValue* context,
                            HValue* left,
@@ skipping 605 matching lines @@
   virtual bool IsDeletable() const { return true; }
 };
 
 
 #undef DECLARE_INSTRUCTION
 #undef DECLARE_CONCRETE_INSTRUCTION
 
 } }  // namespace v8::internal
 
 #endif  // V8_HYDROGEN_INSTRUCTIONS_H_