Move field index into property details, freeing up the value slot of fields.

src/property.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 26 matching lines @@
 
 // Abstraction for elements in instance-descriptor arrays.
 //
 // Each descriptor has a key, property attributes, property type,
 // property index (in the actual instance-descriptor array) and
 // optionally a piece of data.
 //
 
 class Descriptor BASE_EMBEDDED {
  public:
-  static int IndexFromValue(Object* value) {
-    return Smi::cast(value)->value();
-  }
-
   MUST_USE_RESULT MaybeObject* KeyToUniqueName() {
     if (!key_->IsUniqueName()) {
       MaybeObject* maybe_result = HEAP->InternalizeString(String::cast(key_));
       if (!maybe_result->To(&key_)) return maybe_result;
     }
     return key_;
   }
 
   Name* GetKey() { return key_; }
   Object* GetValue() { return value_; }
@@ skipping 21 matching lines @@
 
   Descriptor(Name* key, Object* value, PropertyDetails details)
       : key_(key),
         value_(value),
         details_(details) { }
 
   Descriptor(Name* key,
              Object* value,
              PropertyAttributes attributes,
              PropertyType type,
-             Representation representation)
+             Representation representation,
+             int field_index = 0)
       : key_(key),
         value_(value),
-        details_(attributes, type, representation) { }
+        details_(attributes, type, representation, field_index) { }
 
   friend class DescriptorArray;
 };
 
 
 class FieldDescriptor: public Descriptor {
  public:
   FieldDescriptor(Name* key,
                   int field_index,
                   PropertyAttributes attributes,
                   Representation representation)
-      : Descriptor(key, Smi::FromInt(field_index), attributes,
-                   FIELD, representation) {}
+      : Descriptor(key, Smi::FromInt(0), attributes,
+                   FIELD, representation, field_index) {}
 };
 
 
 class ConstantFunctionDescriptor: public Descriptor {
  public:
   ConstantFunctionDescriptor(Name* key,
                              JSFunction* function,
                              PropertyAttributes attributes)
       : Descriptor(key, function, attributes, CONSTANT_FUNCTION,
                    Representation::Tagged()) {}
@@ skipping 185 matching lines @@
     return details_.type() == NORMAL;
   }
 
   bool IsConstantFunction() {
     ASSERT(!(details_.type() == CONSTANT_FUNCTION && !IsFound()));
     return details_.type() == CONSTANT_FUNCTION;
   }
 
   bool IsDontDelete() { return details_.IsDontDelete(); }
   bool IsDontEnum() { return details_.IsDontEnum(); }
-  bool IsDeleted() { return details_.IsDeleted(); }
   bool IsFound() { return lookup_type_ != NOT_FOUND; }
   bool IsTransition() { return lookup_type_ == TRANSITION_TYPE; }
   bool IsHandler() { return lookup_type_ == HANDLER_TYPE; }
   bool IsInterceptor() { return lookup_type_ == INTERCEPTOR_TYPE; }
 
   // Is the result is a property excluding transitions and the null descriptor?
   bool IsProperty() {
     return IsFound() && !IsTransition();
   }
 
@@ skipping 85 matching lines @@
   }
 
   int GetDescriptorIndex() {
     ASSERT(lookup_type_ == DESCRIPTOR_TYPE);
     return number_;
   }
 
   PropertyIndex GetFieldIndex() {
     ASSERT(lookup_type_ == DESCRIPTOR_TYPE);
     ASSERT(IsField());
-    return PropertyIndex::NewFieldIndex(
-        Descriptor::IndexFromValue(GetValue()));
+    return PropertyIndex::NewFieldIndex(GetFieldIndexFromMap(holder()->map()));
   }
 
   int GetLocalFieldIndexFromMap(Map* map) {
     ASSERT(IsField());
-    return Descriptor::IndexFromValue(GetValueFromMap(map)) -
-        map->inobject_properties();
+    return GetFieldIndexFromMap(map) - map->inobject_properties();
   }
 
   int GetDictionaryEntry() {
     ASSERT(lookup_type_ == DICTIONARY_TYPE);
     return number_;
   }
 
   JSFunction* GetConstantFunction() {
     ASSERT(type() == CONSTANT_FUNCTION);
     return JSFunction::cast(GetValue());
@@ skipping 21 matching lines @@
     ASSERT(lookup_type_ == DICTIONARY_TYPE);
     return holder()->GetNormalizedProperty(this);
   }
 
   Object* GetValueFromMap(Map* map) const {
     ASSERT(lookup_type_ == DESCRIPTOR_TYPE);
     ASSERT(number_ < map->NumberOfOwnDescriptors());
     return map->instance_descriptors()->GetValue(number_);
   }
 
+  int GetFieldIndexFromMap(Map* map) const {
+    ASSERT(lookup_type_ == DESCRIPTOR_TYPE);
+    ASSERT(number_ < map->NumberOfOwnDescriptors());
+    return map->instance_descriptors()->GetFieldIndex(number_);
+  }
+
   void Iterate(ObjectVisitor* visitor);
 
  private:
   Isolate* isolate_;
   LookupResult* next_;
 
   // Where did we find the result;
   enum {
     NOT_FOUND,
     DESCRIPTOR_TYPE,
     TRANSITION_TYPE,
     DICTIONARY_TYPE,
     HANDLER_TYPE,
     INTERCEPTOR_TYPE
   } lookup_type_;
 
   JSReceiver* holder_;
   int number_;
   bool cacheable_;
   PropertyDetails details_;
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_PROPERTY_H_