[LoadIC] Handle simple field loads in the dispatcher

src/field-index.h

 // 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.
 
 #ifndef V8_FIELD_INDEX_H_
 #define V8_FIELD_INDEX_H_
 
 #include "src/property-details.h"
 #include "src/utils.h"
 
 namespace v8 {
 namespace internal {
 
 class Map;
 
 // Wrapper class to hold a field index, usually but not necessarily generated
 // from a property index. When available, the wrapper class captures additional
 // information to allow the field index to be translated back into the property
 // index it was originally generated from.
 class FieldIndex final {
  public:
   FieldIndex() : bit_field_(0) {}
 
   static FieldIndex ForPropertyIndex(Map* map,
                                      int index,
                                      bool is_double = false);
   static FieldIndex ForInObjectOffset(int offset, Map* map = NULL);
   static FieldIndex ForDescriptor(Map* map, int descriptor_index);
   static FieldIndex ForLoadByFieldIndex(Map* map, int index);
+  static FieldIndex ForLoadByFieldOffset(Map* map, int index);
   static FieldIndex ForKeyedLookupCacheIndex(Map* map, int index);
   static FieldIndex FromFieldAccessStubKey(int key);
 
   int GetLoadByFieldIndex() const;
+  int GetLoadByFieldOffset() const;
 
   bool is_inobject() const {
     return IsInObjectBits::decode(bit_field_);
   }
 
   bool is_hidden_field() const { return IsHiddenField::decode(bit_field_); }
 
   bool is_double() const {
     return IsDoubleBits::decode(bit_field_);
   }
@@ skipping 66 matching lines @@
       : public BitField<bool, FirstInobjectPropertyOffsetBits::kNext, 1> {};
   STATIC_ASSERT(IsHiddenField::kNext <= 32);
 
   int bit_field_;
 };
 
 }  // namespace internal
 }  // namespace v8
 
 #endif