Let DescriptorArray::Append insert at proper position, avoiding need for resorting.

src/objects.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 152 matching lines @@
 };
 
 
 // Indicates whether a get method should implicitly create the object looked up.
 enum CreationFlag {
   ALLOW_CREATION,
   OMIT_CREATION
 };
 
 
-// Indicates whether the search function should expect a sorted or an unsorted
-// array as input.
-enum SearchMode {
-  EXPECT_SORTED,
-  EXPECT_UNSORTED
-};
-
-
 // Indicates whether transitions can be added to a source map or not.
 enum TransitionFlag {
   INSERT_TRANSITION,
   OMIT_TRANSITION
 };
 
 
 // Instance size sentinel for objects of variable size.
 const int kVariableSizeSentinel = 0;
 
@@ skipping 2386 matching lines @@
   enum SharedMode {
     MAY_BE_SHARED,
     CANNOT_BE_SHARED
   };
 
   // Return a copy of the array with all transitions and null descriptors
   // removed. Return a Failure object in case of an allocation failure.
   MUST_USE_RESULT MaybeObject* Copy(SharedMode shared_mode);
 
   // Sort the instance descriptors by the hash codes of their keys.
-  // Does not check for duplicates.
-  void SortUnchecked(const WhitenessWitness&);
-
-  // Sort the instance descriptors by the hash codes of their keys.
-  // Checks the result for duplicates.
   void Sort(const WhitenessWitness&);
 
   // Search the instance descriptors for given name.
   INLINE(int Search(String* name));
 
   // As the above, but uses DescriptorLookupCache and updates it when
   // necessary.
   INLINE(int SearchWithCache(String* name));
 
   // Tells whether the name is present int the array.
@@ skipping 105 matching lines @@
 
   // Swap first and second descriptor.
   inline void NoIncrementalWriteBarrierSwapDescriptors(
       int first, int second);
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(DescriptorArray);
 };
 
 
 template<typename T>
-inline int LinearSearch(T* array, SearchMode mode, String* name, int len);
+inline int LinearSearch(T* array, String* name, int len);
 
 
 template<typename T>
 inline int Search(T* array, String* name);
 
 
 // HashTable is a subclass of FixedArray that implements a hash table
 // that uses open addressing and quadratic probing.
 //
 // In order for the quadratic probing to work, elements that have not
@@ skipping 2120 matching lines @@
   // [prototype]: implicit prototype object.
   DECL_ACCESSORS(prototype, Object)
 
   // [constructor]: points back to the function responsible for this map.
   DECL_ACCESSORS(constructor, Object)
 
   inline JSFunction* unchecked_constructor();
 
   // [instance descriptors]: describes the object.
   DECL_ACCESSORS(instance_descriptors, DescriptorArray)
+  inline void InitializeDescriptors(DescriptorArray* descriptors);
 
   // Should only be called to clear a descriptor array that was only used to
   // store transitions and does not contain any live transitions anymore.
   inline void ClearDescriptorArray(Heap* heap, WriteBarrierMode mode);
 
   // [stub cache]: contains stubs compiled for this map.
   DECL_ACCESSORS(code_cache, Object)
 
   // [back pointer]: points back to the parent map from which a transition
   // leads to this map. The field overlaps with prototype transitions and the
@@ skipping 4028 matching lines @@
     } else {
       value &= ~(1 << bit_position);
     }
     return value;
   }
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_OBJECTS_H_