Hydrogenize (and share) part of StoreTransition handler as a StoreTransitionStub.

src/code-stubs-hydrogen.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/v8.h"
 
 #include "src/bailout-reason.h"
 #include "src/code-stubs.h"
 #include "src/field-index.h"
 #include "src/hydrogen.h"
@@ skipping 758 matching lines @@
   BuildStoreNamedField(GetParameter(0), GetParameter(2), casted_stub()->index(),
                        casted_stub()->representation(), false);
   return GetParameter(2);
 }
 
 
 Handle<Code> StoreFieldStub::GenerateCode() { return DoGenerateCode(this); }
 
 
 template <>
-HValue* CodeStubGraphBuilder<ExtendStorageStub>::BuildCodeStub() {
-  HValue* object = GetParameter(ExtendStorageDescriptor::kReceiverIndex);
-  HValue* properties =
-      Add<HLoadNamedField>(object, static_cast<HValue*>(NULL),
-                           HObjectAccess::ForPropertiesPointer());
-  HValue* length = AddLoadFixedArrayLength(properties);
-  HValue* delta = Add<HConstant>(static_cast<int32_t>(JSObject::kFieldsAdded));
-  HValue* new_capacity = AddUncasted<HAdd>(length, delta);
+HValue* CodeStubGraphBuilder<StoreTransitionStub>::BuildCodeStub() {
+  HValue* object = GetParameter(StoreTransitionDescriptor::kReceiverIndex);
 
-  // Grow properties array.
-  ElementsKind kind = FAST_ELEMENTS;
-  Add<HBoundsCheck>(new_capacity,
-                    Add<HConstant>((Page::kMaxRegularHeapObjectSize -
-                                    FixedArray::kHeaderSize) >>
-                                   ElementsKindToShiftSize(kind)));
+  switch (casted_stub()->store_mode()) {
+    case StoreTransitionStub::ExtendStorageAndStoreMapAndValue: {
+      HValue* properties =
+          Add<HLoadNamedField>(object, static_cast<HValue*>(NULL),
+                               HObjectAccess::ForPropertiesPointer());
+      HValue* length = AddLoadFixedArrayLength(properties);
+      HValue* delta =
+          Add<HConstant>(static_cast<int32_t>(JSObject::kFieldsAdded));
+      HValue* new_capacity = AddUncasted<HAdd>(length, delta);
 
-  // Reuse this code for properties backing store allocation.
-  HValue* new_properties = BuildAllocateAndInitializeArray(kind, new_capacity);
+      // Grow properties array.
+      ElementsKind kind = FAST_ELEMENTS;
+      Add<HBoundsCheck>(new_capacity,
+                        Add<HConstant>((Page::kMaxRegularHeapObjectSize -
+                                        FixedArray::kHeaderSize) >>
+                                       ElementsKindToShiftSize(kind)));
 
-  BuildCopyProperties(properties, new_properties, length, new_capacity);
+      // Reuse this code for properties backing store allocation.
+      HValue* new_properties =
+          BuildAllocateAndInitializeArray(kind, new_capacity);
 
-  // Store the new value into the "extended" object.
-  Add<HStoreNamedField>(object, HObjectAccess::ForPropertiesPointer(),
-                        new_properties);
+      BuildCopyProperties(properties, new_properties, length, new_capacity);
 
-  BuildStoreNamedField(
-      object, GetParameter(ExtendStorageDescriptor::kValueIndex),
-      casted_stub()->index(), casted_stub()->representation(), true);
+      // Store the new value into the "extended" object.
+      Add<HStoreNamedField>(object, HObjectAccess::ForPropertiesPointer(),
+                            new_properties);
+    }
+    // Fall through.
+    case StoreTransitionStub::StoreMapAndValue:
+      BuildStoreNamedField(
+          object, GetParameter(StoreTransitionDescriptor::kValueIndex),
+          casted_stub()->index(), casted_stub()->representation(), true);
+    // Fall through.
 
-  // And finally update the map after the new field is added.
-  Add<HStoreNamedField>(object, HObjectAccess::ForMap(),
-                        GetParameter(ExtendStorageDescriptor::kMapIndex));
-
-  return GetParameter(ExtendStorageDescriptor::kValueIndex);
+    case StoreTransitionStub::StoreMapOnly:
+      // And finally update the map.
+      Add<HStoreNamedField>(object, HObjectAccess::ForMap(),
+                            GetParameter(StoreTransitionDescriptor::kMapIndex));
+      break;
+  }
+  return GetParameter(StoreTransitionDescriptor::kValueIndex);
 }
 
 
-Handle<Code> ExtendStorageStub::GenerateCode() { return DoGenerateCode(this); }
+Handle<Code> StoreTransitionStub::GenerateCode() {
+  return DoGenerateCode(this);
+}
 
 
 template <>
 HValue* CodeStubGraphBuilder<StringLengthStub>::BuildCodeStub() {
   HValue* string = BuildLoadNamedField(GetParameter(0),
       FieldIndex::ForInObjectOffset(JSValue::kValueOffset));
   return BuildLoadNamedField(string,
       FieldIndex::ForInObjectOffset(String::kLengthOffset));
 }
 
@@ skipping 1175 matching lines @@
 
   // Probe the stub cache.
   Code::Flags flags = Code::RemoveTypeAndHolderFromFlags(
       Code::ComputeHandlerFlags(Code::LOAD_IC));
   Add<HTailCallThroughMegamorphicCache>(receiver, name, flags);
 
   // We never continue.
   return graph()->GetConstant0();
 }
 } }  // namespace v8::internal