[SystemZ][z/OS] Fix return values in AutoConversion functions

[abhina.sreeskantharajan]

Summary

My previous patch https://reviews.llvm.org/rG1527a5e4b4834e65678f9c30f786a2f4c17932bf incorrectly set int return values instead of std::error_code. This patch correctly returns and std::error_code value.

[Jonathan.Crowther]

LGTM

[fanbo-meng]

LGTM

llvm/lib/Support/AutoConvert.cpp

 #include <sys/stat.h>
 
 std::error_code llvm::disableAutoConversion(int FD) {
   static const struct f_cnvrt Convert = {
       SETCVTOFF,        // cvtcmd
       0,                // pccsid
       (short)FT_BINARY, // fccsid
   };
-  return fcntl(FD, F_CONTROL_CVT, &Convert);
+  if (fcntl(FD, F_CONTROL_CVT, &Convert) == -1)
+    return std::error_code(errno, std::generic_category());
+  return std::error_code();
 }
 
 std::error_code llvm::enableAutoConversion(int FD) {
   struct f_cnvrt Query = {
       QUERYCVT, // cvtcmd
       0,        // pccsid
       0,        // fccsid
   };
 
   if (fcntl(FD, F_CONTROL_CVT, &Query) == -1)
-    return -1;
+    return std::error_code(errno, std::generic_category());
 
   Query.cvtcmd = SETCVTALL;
   Query.pccsid =
       (FD == STDIN_FILENO || FD == STDOUT_FILENO || FD == STDERR_FILENO)
           ? 0
           : CCSID_UTF_8;
   // Assume untagged files to be IBM-1047 encoded.
   Query.fccsid = (Query.fccsid == FT_UNTAGGED) ? CCSID_IBM_1047 : Query.fccsid;
-  return fcntl(FD, F_CONTROL_CVT, &Query);
+  if (fcntl(FD, F_CONTROL_CVT, &Query) == -1)
+    return std::error_code(errno, std::generic_category());
+  return std::error_code();
 }
 
 std::error_code llvm::setFileTag(int FD, int CCSID, bool Text) {
   assert((!Text || (CCSID != FT_UNTAGGED && CCSID != FT_BINARY)) &&
          "FT_UNTAGGED and FT_BINARY are not allowed for text files");
   struct file_tag Tag;
   Tag.ft_ccsid = CCSID;
   Tag.ft_txtflag = Text;
   Tag.ft_deferred = 0;
   Tag.ft_rsvflags = 0;
 
-  return fcntl(FD, F_SETTAG, &Tag);
+  if (fcntl(FD, F_SETTAG, &Tag) == -1)
+    return std::error_code(errno, std::generic_category());
+  return std::error_code();
 }
 
 #endif // __MVS__