MSan does not understand inline asm. This change preinitializes cpuid

src/v8utils.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 197 matching lines @@
 #define STOS "stosq"
 #endif
 #if defined(__native_client__)
   // This STOS sequence does not validate for x86_64 Native Client.
   // Here we #undef STOS to force use of the slower C version.
   // TODO(bradchen): Profile V8 and implement a faster REP STOS
   // here if the profile indicates it matters.
 #undef STOS
 #endif
 
+#if defined(MEMORY_SANITIZER)
+  // MemorySanitizer does not understand inline assembly.
+#undef STOS
+#endif
+
 #if defined(__GNUC__) && defined(STOS)
   asm volatile(
       "cld;"
       "rep ; " STOS
       : "+&c" (counter), "+&D" (dest)
       : "a" (value)
       : "memory", "cc");
 #else
   for (int i = 0; i < counter; i++) {
     dest[i] = value;
@@ skipping 227 matching lines @@
 
   // Add formatted contents like printf based on a va_list.
   void AddFormattedList(const char* format, va_list list);
  private:
   DISALLOW_IMPLICIT_CONSTRUCTORS(StringBuilder);
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_V8UTILS_H_