Merge r5518 into 2.3 branch.

src/objects.h

Index: src/objects.h
===================================================================
--- src/objects.h	(revision 5520)
+++ src/objects.h	(working copy)
@@ -201,6 +201,14 @@
 };
 
 
+// NormalizedMapSharingMode is used to specify whether a map may be shared
+// by different objects with normalized properties.
+enum NormalizedMapSharingMode {
+  UNIQUE_NORMALIZED_MAP,
+  SHARED_NORMALIZED_MAP
+};
+
+
 // Instance size sentinel for objects of variable size.
 static const int kVariableSizeSentinel = 0;
 
@@ -2480,12 +2488,8 @@
  public:
   static const int kEntries = 64;
 
-  static bool IsCacheable(JSObject* object);
-
   Object* Get(JSObject* object, PropertyNormalizationMode mode);
 
-  bool Contains(Map* map);
-
   void Clear();
 
   // Casting
@@ -3141,6 +3145,13 @@
     return ((1 << kHasFastElements) & bit_field2()) != 0;
   }
 
+  // Tells whether the map is shared between objects that may have different
+  // behavior. If true, the map should never be modified, instead a clone
+  // should be created and modified.
+  inline void set_is_shared(bool value);
+
+  inline bool is_shared();
+
   // Tells whether the instance needs security checks when accessing its
   // properties.
   inline void set_is_access_check_needed(bool access_check_needed);
@@ -3160,7 +3171,8 @@
 
   Object* CopyDropDescriptors();
 
-  Object* CopyNormalized(PropertyNormalizationMode mode);
+  Object* CopyNormalized(PropertyNormalizationMode mode,
+                         NormalizedMapSharingMode sharing);
 
   // Returns a copy of the map, with all transitions dropped from the
   // instance descriptors.
@@ -3224,7 +3236,7 @@
 #ifdef DEBUG
   void MapPrint();
   void MapVerify();
-  void NormalizedMapVerify();
+  void SharedMapVerify();
 #endif
 
   inline int visitor_id();
@@ -3285,6 +3297,7 @@
   static const int kFunctionWithPrototype = 1;
   static const int kHasFastElements = 2;
   static const int kStringWrapperSafeForDefaultValueOf = 3;
+  static const int kIsShared = 5;
 
   // Layout of the default cache. It holds alternating name and code objects.
   static const int kCodeCacheEntrySize = 2;