Add static cast to unsigned char whenever a character classification function is called with a signed char argument, in order to avoid assertions in Windows Debug configuration.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@175006 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Object/MachOObjectFile.cpp

@@ -273,7 +273,7 @@ error_code MachOObjectFile::getSymbolNMTypeChar(DataRefImpl DRI,
   }
 
   if (Flags & (macho::STF_External | macho::STF_PrivateExtern))
-    Char = toupper(Char);
+    Char = toupper(static_cast<unsigned char>(Char));
   Result = Char;
   return object_error::success;
 }