More cleanly separate adding from setting elements

src/lookup.cc

 // Copyright 2014 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/bootstrapper.h"
 #include "src/deoptimizer.h"
 #include "src/lookup.h"
 #include "src/lookup-inl.h"
@@ skipping 155 matching lines @@
 }
 
 
 void LookupIterator::ReconfigureDataProperty(Handle<Object> value,
                                              PropertyAttributes attributes) {
   DCHECK(state_ == DATA || state_ == ACCESSOR);
   DCHECK(HolderIsReceiverOrHiddenPrototype());
   Handle<JSObject> holder = GetHolder<JSObject>();
   if (IsElement()) {
     // TODO(verwaest): Clean up.
-    if (attributes == NONE && !holder->HasDictionaryElements() &&
-        !holder->HasDictionaryArgumentsElements()) {
-      ElementsAccessor* accessor = holder->GetElementsAccessor();
-      accessor->Set(holder, index(), value);
+    DCHECK(holder->HasFastElements() || holder->HasDictionaryElements() ||
+           holder->HasSloppyArgumentsElements());
+    DCHECK(attributes != NONE || !holder->HasFastElements());
+    Handle<SeededNumberDictionary> d = JSObject::NormalizeElements(holder);
+    // TODO(verwaest): Move this into NormalizeElements.
+    d->set_requires_slow_elements();
+    if (holder->HasDictionaryElements()) {
+      JSObject::SetDictionaryElement(holder, index(), value, attributes);
     } else {
-      DCHECK(holder->HasFastElements() || holder->HasDictionaryElements() ||
-             holder->HasSloppyArgumentsElements());
-      Handle<SeededNumberDictionary> d = JSObject::NormalizeElements(holder);
-      // TODO(verwaest): Move this into NormalizeElements.
-      d->set_requires_slow_elements();
-      if (holder->HasDictionaryElements()) {
-        JSObject::SetDictionaryElement(holder, index(), value, attributes);
-      } else {
-        JSObject::SetSloppyArgumentsElement(holder, index(), value, attributes);
-      }
+      JSObject::SetDictionaryArgumentsElement(holder, index(), value,
+                                              attributes);
     }
   } else if (holder_map_->is_dictionary_map()) {
     PropertyDetails details(attributes, v8::internal::DATA, 0,
                             PropertyCellType::kMutable);
     JSObject::SetNormalizedProperty(holder, name(), value, details);
   } else {
     holder_map_ = Map::ReconfigureExistingProperty(
         holder_map_, descriptor_number(), i::kData, attributes);
     holder_map_ =
         Map::PrepareForDataProperty(holder_map_, descriptor_number(), value);
@@ skipping 302 matching lines @@
       case InterceptorState::kSkipNonMasking:
         return true;
       case InterceptorState::kProcessNonMasking:
         return false;
     }
   }
   return interceptor_state_ == InterceptorState::kProcessNonMasking;
 }
 }  // namespace internal
 }  // namespace v8