Add an assigned variables analysis....

src/ia32/macro-assembler-ia32.h

 // Copyright 2006-2009 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 161 matching lines @@
     ASSERT(kSmiTag == 0);
     shl(reg, kSmiTagSize);
   }
   void SmiUntag(Register reg) {
     sar(reg, kSmiTagSize);
   }
 
   // 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 372 matching lines @@
   }                                                                       \
   masm->
 #else
 #define ACCESS_MASM(masm) masm->
 #endif
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_IA32_MACRO_ASSEMBLER_IA32_H_