Only extend storage if FIELD

R=jkummerow@chromium.org

Review URL: https://chromiumcodereview.appspot.com/16818014

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@15125 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/arm/stub-cache-arm.cc

@@ -547,7 +547,8 @@ void StubCompiler::GenerateStoreTransition(MacroAssembler* masm,
   ASSERT(object->IsJSGlobalProxy() || !object->IsAccessCheckNeeded());
 
   // Perform map transition for the receiver if necessary.
-  if (object->map()->unused_property_fields() == 0) {
+  if (details.type() == FIELD &&
+      object->map()->unused_property_fields() == 0) {
     // The properties must be extended before we can store the value.
     // We jump to a runtime call that extends the properties array.
     __ push(receiver_reg);

src/ia32/stub-cache-ia32.cc

@@ -890,7 +890,8 @@ void StubCompiler::GenerateStoreTransition(MacroAssembler* masm,
   ASSERT(object->IsJSGlobalProxy() || !object->IsAccessCheckNeeded());
 
   // Perform map transition for the receiver if necessary.
-  if (object->map()->unused_property_fields() == 0) {
+  if (details.type() == FIELD &&
+      object->map()->unused_property_fields() == 0) {
     // The properties must be extended before we can store the value.
     // We jump to a runtime call that extends the properties array.
     __ pop(scratch1);  // Return address.

src/x64/stub-cache-x64.cc

@@ -850,7 +850,8 @@ void StubCompiler::GenerateStoreTransition(MacroAssembler* masm,
   ASSERT(object->IsJSGlobalProxy() || !object->IsAccessCheckNeeded());
 
   // Perform map transition for the receiver if necessary.
-  if (object->map()->unused_property_fields() == 0) {
+  if (details.type() == FIELD &&
+      object->map()->unused_property_fields() == 0) {
     // The properties must be extended before we can store the value.
     // We jump to a runtime call that extends the properties array.
     __ pop(scratch1);  // Return address.