[turbofan] Refactor the lowering of element/property accesses.

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"
 
@@ skipping 58 matching lines @@
     return result;
   }
 
   int GetKeyedLookupCacheIndex() const;
 
   int GetFieldAccessStubKey() const {
     return bit_field_ &
         (IsInObjectBits::kMask | IsDoubleBits::kMask | IndexBits::kMask);
   }
 
+  bool operator==(FieldIndex const& other) const {
+    return bit_field_ == other.bit_field_;
+  }
+  bool operator!=(FieldIndex const& other) const { return !(*this == other); }
+
   // For GetLoadByFieldOffset.
   class FieldOffsetIsInobject : public BitField<bool, 1, 1> {};
   class FieldOffsetIsDouble : public BitField<bool, 2, 1> {};
   class FieldOffsetOffset : public BitField<int, 3, 27> {};
   // Make sure we don't overflow into the sign bit.
   STATIC_ASSERT(FieldOffsetOffset::kNext <= kSmiValueSize - 1);
 
  private:
   FieldIndex(bool is_inobject, int local_index, bool is_double,
              int inobject_properties, int first_inobject_property_offset,
@@ skipping 30 matching lines @@
       : public BitField<bool, FirstInobjectPropertyOffsetBits::kNext, 1> {};
   STATIC_ASSERT(IsHiddenField::kNext <= 32);
 
   int bit_field_;
 };
 
 }  // namespace internal
 }  // namespace v8
 
 #endif