[llvm-size] Fix hang on invalid short commandline option

[gbreynoo]

Summary

When an invalid shot command line option was used (e.g. -v) llvm-size would hang. This change fixes this issue by bringing llvm-size in line with other llvm tools and exiting early when this error is output.

[MaskRay]

When an invalid shot command line option was used (e.g. -v) llvm-size would hang.

Thanks for catching the bug. llvm-size does not hang. It is waiting on input from stdin.

[jhenderson]

In the commit message: "When an invalid short command" (typo: "shot" -> "short"). To address @MaskRay's comment, I'd change "hang" to "hang waiting for input".

llvm/tools/llvm-size/llvm-size.cpp

 }
 
 int main(int argc, char **argv) {
   InitLLVM X(argc, argv);
   BumpPtrAllocator A;
   StringSaver Saver(A);
   SizeOptTable Tbl;
   ToolName = argv[0];
-  opt::InputArgList Args = Tbl.parseArgs(argc, argv, OPT_UNKNOWN, Saver,
-                                         [&](StringRef Msg) { error(Msg); });
+  opt::InputArgList Args =
+      Tbl.parseArgs(argc, argv, OPT_UNKNOWN, Saver, [&](StringRef Msg) {
+        error(Msg);
+        exit(1);
+      });
   if (Args.hasArg(OPT_help)) {
     Tbl.printHelp(
         outs(),
         (Twine(ToolName) + " [options] <input object files>").str().c_str(),
         "LLVM object size dumper");
     // TODO Replace this with OptTable API once it adds extrahelp support.
     outs() << "\nPass @FILE as argument to read options from FILE.\n";
     return 0;