Remove prototype checks for leaf maps in optimized code.

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 4688 matching lines @@
 // All code indexes used in the class are counted starting from the first
 // code object of the first group. In other words, code index 0 corresponds
 // to array index n = kCodesStartIndex.
 
 class DependentCodes: public FixedArray {
  public:
   enum DependencyGroup {
     // Group of codes that weakly embed this map and depend on being
     // deoptimized when the map is garbage collected.
     kWeaklyEmbeddedGroup,
-    kGroupCount = kWeaklyEmbeddedGroup + 1
+    // Group of codes that omitted prototype check for a prototype with this map
+    // and depend on being deoptimized when map layout changes.
+    kPrototypeCheckGroup,
+    kGroupCount = kPrototypeCheckGroup + 1
   };
   // Array for holding the index of the first code object of each group.
   // The last element stores the total number of code objects.
   typedef int GroupStartIndexes[kGroupCount + 1];
   inline int number_of_codes(DependencyGroup group);
   inline void set_number_of_codes(DependencyGroup group, int value);
   inline Code* code_at(int i);
   inline void set_code_at(int i, Code* value);
   inline Object** code_slot_at(int i);
   inline void clear_code_at(int i);
@@ skipping 455 matching lines @@
 
   bool CanTransition() {
     // Only JSObject and subtypes have map transitions and back pointers.
     STATIC_ASSERT(LAST_TYPE == LAST_JS_OBJECT_TYPE);
     return instance_type() >= FIRST_JS_OBJECT_TYPE;
   }
 
   inline void AddDependentCode(DependentCodes::DependencyGroup group,
                                Handle<Code> code);
 
+  void DeoptimizeDependentCodes(DependentCodes::DependencyGroup group);
+
   // Dispatched behavior.
   DECLARE_PRINTER(Map)
   DECLARE_VERIFIER(Map)
 
 #ifdef VERIFY_HEAP
   void SharedMapVerify();
 #endif
 
   inline int visitor_id();
   inline void set_visitor_id(int visitor_id);
@@ skipping 3719 matching lines @@
     } else {
       value &= ~(1 << bit_position);
     }
     return value;
   }
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_OBJECTS_H_