s390: introduce DUMY opcode for special use.

src/s390/assembler-s390.h

 // Copyright (c) 1994-2006 Sun Microsystems Inc.
 // 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.
 //
@@ skipping 1206 matching lines @@
     PROPERTY_ACCESS_INLINED,
     PROPERTY_ACCESS_INLINED_CONTEXT,
     PROPERTY_ACCESS_INLINED_CONTEXT_DONT_DELETE,
     // Helper values.
     LAST_CODE_MARKER,
     FIRST_IC_MARKER = PROPERTY_ACCESS_INLINED
   };
 
   void nop(int type = 0);  // 0 is the default non-marking type.
 
+  void dumy(int r1, int x2, int b2, int d2);
+
   // Check the code size generated from label to here.
   int SizeOfCodeGeneratedSince(Label* label) {
     return pc_offset() - label->pos();
   }
 
   // Debugging
 
   // Mark address of a debug break slot.
   void RecordDebugBreakSlot(RelocInfo::Mode mode);
 
@@ skipping 226 matching lines @@
 
 class EnsureSpace BASE_EMBEDDED {
  public:
   explicit EnsureSpace(Assembler* assembler) { assembler->CheckBuffer(); }
 };
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_S390_ASSEMBLER_S390_H_