Avoid one repeated property lookup when computing load ICs.

src/field-index.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/field-index.h"
+#include "src/lookup.h"
 #include "src/objects.h"
 #include "src/objects-inl.h"
 
 namespace v8 {
 namespace internal {
 
 
 FieldIndex FieldIndex::ForLookupResult(const LookupResult* lookup_result) {
   Map* map = lookup_result->holder()->map();
   return ForPropertyIndex(map,
                           lookup_result->GetFieldIndexFromMap(map),
                           lookup_result->representation().IsDouble());
 }
 
 
+FieldIndex FieldIndex::ForLookupIterator(const LookupIterator* lookup) {

[Toon Verwaest, 2014/07/30 16:54:52]

Let the LookupIterator calculate the FieldIndex instead, perhaps by calling a
lower-level interface on FieldIndex.

[Jakob Kummerow, 2014/07/31 13:55:50]

Done.

+  Handle<Map> map = lookup->holder_map();
+  int index =
+      map->instance_descriptors()->GetFieldIndex(lookup->descriptor_number());
+  return ForPropertyIndex(*map, index, lookup->representation().IsDouble());
+}
 } }  // namespace v8::internal