Add complete ElementKind information directly to Map for objects with elements.

src/x64/macro-assembler-x64.h

 // Copyright 2011 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 735 matching lines @@
   // Compare object type for heap object.
   // Always use unsigned comparisons: above and below, not less and greater.
   // Incoming register is heap_object and outgoing register is map.
   // They may be the same register, and may be kScratchRegister.
   void CmpObjectType(Register heap_object, InstanceType type, Register map);
 
   // Compare instance type for map.
   // Always use unsigned comparisons: above and below, not less and greater.
   void CmpInstanceType(Register map, InstanceType type);
 
+  // Check if a map for a JSObject indicates that the object has fast elements.
+  // Jump to the specified label if it does not.
+  void CheckFastElements(Register map,
+                         Label* fail,
+                         Label::Distance distance = Label::kFar);
+
   // Check if the map of an object is equal to a specified map and
   // branch to label if not. Skip the smi check if not required
   // (object is known to be a heap object)
   void CheckMap(Register obj,
                 Handle<Map> map,
                 Label* fail,
                 SmiCheckType smi_check_type);
 
   // Check if the map of an object is equal to a specified map and branch to a
   // specified target if equal. Skip the smi check if not required (object is
@@ skipping 515 matching lines @@
     masm->popfd();                                                        \
   }                                                                       \
   masm->
 #else
 #define ACCESS_MASM(masm) masm->
 #endif
 
 } }  // namespace v8::internal
 
 #endif  // V8_X64_MACRO_ASSEMBLER_X64_H_