Split up HLoadNamedField and HStoreNamedField.

src/hydrogen-instructions.h

Index: src/hydrogen-instructions.h
diff --git a/src/hydrogen-instructions.h b/src/hydrogen-instructions.h
index 4dd24fd871552456a10bb77ab8f6a0e4b4b25138..8fa53b6f1cb646dd3e3b66f3ef9e98b12b01e4d4 100644
--- a/src/hydrogen-instructions.h
+++ b/src/hydrogen-instructions.h
@@ -200,6 +200,7 @@ class LChunkBuilder;
   V(ArrayLengths)                              \
   V(StringLengths)                             \
   V(BackingStoreFields)                        \
+  V(BackingStore)                              \
   V(Calls)                                     \
   V(ContextSlots)                              \
   V(DoubleArrayElements)                       \
@@ -6075,6 +6076,8 @@ class HObjectAccess V8_FINAL {
   static HObjectAccess ForBackingStoreOffset(int offset,
       Representation representation = Representation::Tagged());
 
+  static HObjectAccess ForBackingStore();
+
   // Create an access to a resolved field (in-object or backing store).
   static HObjectAccess ForField(Handle<Map> map,
       LookupResult *lookup, Handle<String> name = Handle<String>::null());
@@ -6136,6 +6139,7 @@ class HObjectAccess V8_FINAL {
     kStringLengths,    // the length of a string
     kElementsPointer,  // elements pointer
     kBackingStore,     // some field in the backing store
+    kBackingStorePointer,  // the backing store itself
     kDouble,           // some double field
     kInobject,         // some other in-object field
     kExternalMemory    // some field in external memory
@@ -6154,9 +6158,9 @@ class HObjectAccess V8_FINAL {
     ASSERT(RepresentationField::decode(value_) == representation.kind());
   }
 
-  class PortionField : public BitField<Portion, 0, 3> {};
-  class RepresentationField : public BitField<Representation::Kind, 3, 4> {};
-  class OffsetField : public BitField<int, 7, 25> {};
+  class PortionField : public BitField<Portion, 0, 4> {};
+  class RepresentationField : public BitField<Representation::Kind, 4, 4> {};
+  class OffsetField : public BitField<int, 8, 24> {};
 
   uint32_t value_;  // encodes portion, representation, and offset
   Handle<String> name_;
@@ -6512,7 +6516,7 @@ class HLoadKeyedGeneric V8_FINAL : public HTemplateInstruction<3> {
 };
 
 
-class HStoreNamedField V8_FINAL : public HTemplateInstruction<3> {
+class HStoreNamedField V8_FINAL : public HTemplateInstruction<2> {
  public:
   DECLARE_INSTRUCTION_FACTORY_P3(HStoreNamedField, HValue*,
                                  HObjectAccess, HValue*);
@@ -6559,28 +6563,16 @@ class HStoreNamedField V8_FINAL : public HTemplateInstruction<3> {
 
   HValue* object() const { return OperandAt(0); }
   HValue* value() const { return OperandAt(1); }
-  HValue* transition() const { return OperandAt(2); }
 
   HObjectAccess access() const { return access_; }
   HValue* new_space_dominator() const { return new_space_dominator_; }
   bool has_transition() const { return has_transition_; }
 
-  Handle<Map> transition_map() const {
-    if (has_transition()) {
-      return Handle<Map>::cast(
-          HConstant::cast(transition())->handle(Isolate::Current()));
-    } else {
-      return Handle<Map>();
-    }
-  }
-
-  void SetTransition(HConstant* map_constant, CompilationInfo* info) {
+  void SetTransition(Handle<Map> map, CompilationInfo* info) {
     ASSERT(!has_transition());  // Only set once.
-    Handle<Map> map = Handle<Map>::cast(map_constant->handle(info->isolate()));
     if (map->CanBeDeprecated()) {
       map->AddDependentCompilationInfo(DependentCode::kTransitionGroup, info);
     }
-    SetOperandAt(2, map_constant);
     has_transition_ = true;
   }
 
@@ -6597,12 +6589,6 @@ class HStoreNamedField V8_FINAL : public HTemplateInstruction<3> {
                                         new_space_dominator());
   }
 
-  bool NeedsWriteBarrierForMap() {
-    if (IsSkipWriteBarrier()) return false;
-    return ReceiverObjectNeedsWriteBarrier(object(), transition(),
-                                           new_space_dominator());
-  }
-
   Representation field_representation() const {
     return access_.representation();
   }
@@ -6621,7 +6607,6 @@ class HStoreNamedField V8_FINAL : public HTemplateInstruction<3> {
         has_transition_(false) {
     SetOperandAt(0, obj);
     SetOperandAt(1, val);
-    SetOperandAt(2, obj);
     access.SetGVNFlags(this, true);
   }