Merge a number of assertion failure fixes to the 3.0 branch.

src/x64/macro-assembler-x64.h

 // Copyright 2010 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 888 matching lines @@
 
   // Calculate the number of stack slots to reserve for arguments when calling a
   // C function.
   int ArgumentStackSlotsForCFunctionCall(int num_arguments);
 
   // ---------------------------------------------------------------------------
   // Utilities
 
   void Ret();
 
+  // Return and drop arguments from stack, where the number of arguments
+  // may be bigger than 2^16 - 1.  Requires a scratch register.
+  void Ret(int bytes_dropped, Register scratch);
+
   Handle<Object> CodeObject() { return code_object_; }
 
 
   // ---------------------------------------------------------------------------
   // StatsCounter support
 
   void SetCounter(StatsCounter* counter, int value);
   void IncrementCounter(StatsCounter* counter, int value);
   void DecrementCounter(StatsCounter* counter, int value);
 
@@ skipping 849 matching lines @@
       Jump(adaptor, RelocInfo::CODE_TARGET);
     }
     bind(&invoke);
   }
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_X64_MACRO_ASSEMBLER_X64_H_