Inline %_ArgumentsLength.

src/x64/macro-assembler-x64.h

 // Copyright 2009 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 485 matching lines @@
                                Register map,
                                Register instance_type);
 
   // FCmp is similar to integer cmp, but requires unsigned
   // jcc instructions (je, ja, jae, jb, jbe, je, and jz).
   void FCmp();
 
   // Abort execution if argument is not a number. Used in debug code.
   void AbortIfNotNumber(Register object, const char* msg);
 
+  // Abort execution if argument is not a smi. Used in debug code.
+  void AbortIfNotSmi(Register object, const char* msg);
+
   // ---------------------------------------------------------------------------
   // Exception handling
 
   // Push a new try handler and link into try handler chain.  The return
   // address must be pushed before calling this helper.
   void PushTryHandler(CodeLocation try_location, HandlerType type);
 
   // Unlink the stack handler on top of the stack from the try handler chain.
   void PopTryHandler();
 
@@ skipping 306 matching lines @@
   }                                                                       \
   masm->
 #else
 #define ACCESS_MASM(masm) masm->
 #endif
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_X64_MACRO_ASSEMBLER_X64_H_