Add checks to runtime functions.

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 6066 matching lines @@
   // until an initial map is needed.
   inline bool has_prototype();
   inline bool has_instance_prototype();
   inline Object* prototype();
   inline Object* instance_prototype();
   MUST_USE_RESULT MaybeObject* SetInstancePrototype(Object* value);
   MUST_USE_RESULT MaybeObject* SetPrototype(Object* value);
 
   // After prototype is removed, it will not be created when accessed, and
   // [[Construct]] from this function will not be allowed.
-  Object* RemovePrototype();
+  void RemovePrototype();
   inline bool should_have_prototype();
 
   // Accessor for this function's initial map's [[class]]
   // property. This is primarily used by ECMA native functions.  This
   // method sets the class_name field of this function's initial map
   // to a given value. It creates an initial map if this function does
   // not have one. Note that this method does not copy the initial map
   // if it has one already, but simply replaces it with the new value.
   // Instances created afterwards will have a map whose [[class]] is
   // set to 'value', but there is no guarantees on instances created
   // before.
-  Object* SetInstanceClassName(String* name);
+  void SetInstanceClassName(String* name);
 
   // Returns if this function has been compiled to native code yet.
   inline bool is_compiled();
 
   // [next_function_link]: Field for linking functions. This list is treated as
   // a weak list by the GC.
   DECL_ACCESSORS(next_function_link, Object)
 
   // Prints the name of the function using PrintF.
   inline void PrintName() {
@@ skipping 2840 matching lines @@
     } else {
       value &= ~(1 << bit_position);
     }
     return value;
   }
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_OBJECTS_H_