Optimistically assume that elements IC only transition once.

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 4293 matching lines @@
 
   // [to_boolean_foo]: For kind TO_BOOLEAN_IC tells what state the stub is in.
   inline byte to_boolean_state();
   inline void set_to_boolean_state(byte value);
 
   // [has_function_cache]: For kind STUB tells whether there is a function
   // cache is passed to the stub.
   inline bool has_function_cache();
   inline void set_has_function_cache(bool flag);
 
+  bool allowed_in_shared_map_code_cache();
+
   // Get the safepoint entry for the given pc.
   SafepointEntry GetSafepointEntry(Address pc);
 
   // Mark this code object as not having a stack check table.  Assumes kind
   // is FUNCTION.
   void SetNoStackCheckTable();
 
   // Find the first map in an IC stub.
   Map* FindFirstMap();
 
@@ skipping 332 matching lines @@
 
   inline bool has_fast_double_elements() {
     return IsFastDoubleElementsKind(elements_kind());
   }
 
   inline bool has_non_strict_arguments_elements() {
     return elements_kind() == NON_STRICT_ARGUMENTS_ELEMENTS;
   }
 
   inline bool has_external_array_elements() {
-    ElementsKind kind(elements_kind());
-    return kind >= FIRST_EXTERNAL_ARRAY_ELEMENTS_KIND &&
-        kind <= LAST_EXTERNAL_ARRAY_ELEMENTS_KIND;
+    return IsExternalArrayElementsKind(elements_kind());
   }
 
   inline bool has_dictionary_elements() {
-    return elements_kind() == DICTIONARY_ELEMENTS;
+    return IsDictionaryElementsKind(elements_kind());
   }
 
   inline bool has_slow_elements_kind() {
     return elements_kind() == DICTIONARY_ELEMENTS
         || elements_kind() == NON_STRICT_ARGUMENTS_ELEMENTS;
   }
 
   static bool IsValidElementsTransition(ElementsKind from_kind,
                                         ElementsKind to_kind);
 
@@ skipping 4015 matching lines @@
     } else {
       value &= ~(1 << bit_position);
     }
     return value;
   }
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_OBJECTS_H_