Make sure to flatten names before lookup. Lookup using cons strings is really slow.

src/objects-inl.h

 // 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.
 //
 // Review notes:
 //
 // - The use of macros in these inline functions may seem superfluous
 // but it is absolutely needed to make sure gcc generates optimal
 // code. gcc is not happy when attempting to inline too deep.
 //
@@ skipping 3208 matching lines @@
 
 
 Handle<String> String::Flatten(Handle<String> string, PretenureFlag pretenure) {
   if (!string->IsConsString()) return string;
   Handle<ConsString> cons = Handle<ConsString>::cast(string);
   if (cons->IsFlat()) return handle(cons->first());
   return SlowFlatten(cons, pretenure);
 }
 
 
+Handle<Name> Name::Flatten(Handle<Name> name, PretenureFlag pretenure) {
+  if (name->IsSymbol()) return name;
+  return String::Flatten(Handle<String>::cast(name));
+}
+
+
 uint16_t String::Get(int index) {
   DCHECK(index >= 0 && index < length());
   switch (StringShape(this).full_representation_tag()) {
     case kSeqStringTag | kOneByteStringTag:
       return SeqOneByteString::cast(this)->SeqOneByteStringGet(index);
     case kSeqStringTag | kTwoByteStringTag:
       return SeqTwoByteString::cast(this)->SeqTwoByteStringGet(index);
     case kConsStringTag | kOneByteStringTag:
     case kConsStringTag | kTwoByteStringTag:
       return ConsString::cast(this)->ConsStringGet(index);
@@ skipping 4119 matching lines @@
 #undef READ_SHORT_FIELD
 #undef WRITE_SHORT_FIELD
 #undef READ_BYTE_FIELD
 #undef WRITE_BYTE_FIELD
 #undef NOBARRIER_READ_BYTE_FIELD
 #undef NOBARRIER_WRITE_BYTE_FIELD
 
 } }  // namespace v8::internal
 
 #endif  // V8_OBJECTS_INL_H_