Better support for 'polymorphic' JS and external arrays

src/ia32/macro-assembler-ia32.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 183 matching lines @@
   void Set(Register dst, const Immediate& x);
   void Set(const Operand& dst, const Immediate& x);
 
   // Compare object type for heap object.
   // Incoming register is heap_object and outgoing register is map.
   void CmpObjectType(Register heap_object, InstanceType type, Register map);
 
   // Compare instance type for map.
   void CmpInstanceType(Register map, InstanceType type);
 
-  // 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)
+  // 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,
                 bool is_heap_object);
 
+  // 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
+  // known to be a heap object)
+  void DispatchMap(Register obj,
+                   Handle<Map> map,
+                   Handle<Code> success,
+                   bool is_heap_object);
+
   // Check if the object in register heap_object is a string. Afterwards the
   // register map contains the object map and the register instance_type
   // contains the instance_type. The registers map and instance_type can be the
   // same in which case it contains the instance type afterwards. Either of the
   // registers map and instance_type can be the same as heap_object.
   Condition IsObjectStringType(Register heap_object,
                                Register map,
                                Register instance_type);
 
   // Check if a heap object's type is in the JSObject range, not including
@@ skipping 559 matching lines @@
   }                                                                       \
   masm->
 #else
 #define ACCESS_MASM(masm) masm->
 #endif
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_IA32_MACRO_ASSEMBLER_IA32_H_