Introduce FieldIndex to unify and abstract property/field offset

src/objects.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.
 
 #ifndef V8_OBJECTS_H_
 #define V8_OBJECTS_H_
 
 #include "src/allocation.h"
 #include "src/assert-scope.h"
 #include "src/builtins.h"
 #include "src/elements-kind.h"
+#include "src/field-index.h"
 #include "src/flags.h"
 #include "src/list.h"
 #include "src/property-details.h"
 #include "src/smart-pointers.h"
 #include "src/unicode-inl.h"
 #if V8_TARGET_ARCH_ARM64
 #include "src/arm64/constants-arm64.h"
 #elif V8_TARGET_ARCH_ARM
 #include "src/arm/constants-arm.h"
 #elif V8_TARGET_ARCH_MIPS
@@ skipping 2471 matching lines @@
   static Handle<SeededNumberDictionary> NormalizeElements(
       Handle<JSObject> object);
 
   // Transform slow named properties to fast variants.
   static void TransformToFastProperties(Handle<JSObject> object,
                                         int unused_property_fields);
 
   // Access fast-case object properties at index.
   static Handle<Object> FastPropertyAt(Handle<JSObject> object,
                                        Representation representation,
-                                       int index);
-  inline Object* RawFastPropertyAt(int index);
-  inline void FastPropertyAtPut(int index, Object* value);
+                                       FieldIndex index);
+  inline Object* RawFastPropertyAt(FieldIndex index);
+  inline void FastPropertyAtPut(FieldIndex index, Object* value);
   void WriteToField(int descriptor, Object* value);
 
   // Access to in object properties.
   inline int GetInObjectPropertyOffset(int index);
   inline Object* InObjectPropertyAt(int index);
   inline Object* InObjectPropertyAtPut(int index,
                                        Object* value,
                                        WriteBarrierMode mode
                                        = UPDATE_WRITE_BARRIER);
 
@@ skipping 8728 matching lines @@
     } else {
       value &= ~(1 << bit_position);
     }
     return value;
   }
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_OBJECTS_H_