[llvm-ar] Implement the V modifier as an alias for --version

[rupprecht]

Summary

Also update the help modifier (h) so that it works as a modifier and not just as a standalone h. For example, llvm-ar h prints the help message, but llvm-ar xh currently prints unknown option h.

[MaskRay]

The V change looks good.

llvm/tools/llvm-ar/llvm-ar.cpp

389

For 'h', I originally did this in D67560, but @grimar suggested the current approach https://reviews.llvm.org/D67560?id=220121#inline-607437

[grimar]

llvm/tools/llvm-ar/llvm-ar.cpp

389

I do not mind to have it here if we want to support it as a modifier. I didn't know it can work like that..

[gbreynoo]

LGTM

llvm/test/tools/llvm-ar/help-message.test

+## Show that the help message for llvm-ar can be printed with either the long
+## flag -help or with the h modifier.
+
 # RUN: llvm-ar h | FileCheck %s
+# RUN: llvm-ar xh | FileCheck %s
 # RUN: llvm-ar -h | FileCheck %s
+# RUN: llvm-ar -xh | FileCheck %s
 # RUN: llvm-ar -help | FileCheck %s
 # RUN: llvm-ar --help | FileCheck %s
 
 # CHECK: USAGE: llvm-ar

llvm/test/tools/llvm-ar/version.test

+## Show that the version for llvm-ar can be printed with either the long flag
+## -version or with the V modifier.
+
+RUN: llvm-ar V | FileCheck %s
+RUN: llvm-ar xV | FileCheck %s
+RUN: llvm-ar -V | FileCheck %s
+RUN: llvm-ar -xV | FileCheck %s
+RUN: llvm-ar -version | FileCheck %s
+RUN: llvm-ar --version | FileCheck %s
+
+CHECK: version

llvm/tools/llvm-ar/llvm-ar.cpp

OPERATIONS:
   t - display contents of archive
   x - extract [files] from the archive
 
 MODIFIERS:
   [a] - put [files] after [relpos]
   [b] - put [files] before [relpos] (same as [i])
   [c] - do not warn if archive had to be created
   [D] - use zero for timestamps and uids/gids (default)
+  [h] - display this help and exit
   [i] - put [files] before [relpos] (same as [b])
   [l] - ignored for compatibility
   [L] - add archive's contents
   [N] - use instance [count] of name
   [o] - preserve original dates
   [P] - use full names when matching (implied for thin archives)
   [s] - create an archive index (cf. ranlib)
   [S] - do not build a symbol table
   [T] - create a thin archive
   [u] - update only [files] newer than archive contents
   [U] - use actual timestamps and uids/gids
   [v] - be verbose about actions taken
+  [V] - display the version and exit
 )";
 
 void printHelpMessage() {
   if (Stem.contains_lower("ranlib"))
     outs() << RanlibHelp;
   else if (Stem.contains_lower("ar"))
     outs() << ArHelp;
 }
for (unsigned i = 0; i < Options.size(); ++i) {
     case 'T':
       Thin = true;
       // Thin archives store path names, so P should be forced.
       CompareFullPath = true;
       break;
     case 'L':
       AddLibrary = true;
       break;
+    case 'V':
+      cl::PrintVersionMessage();
+      exit(0);
+    case 'h':
+      printHelpMessage();
+      exit(0);
     default:
       fail(std::string("unknown option ") + Options[i]);
     }
   }
 
   // At this point, the next thing on the command line must be
   // the archive name.
   getArchive();
static void runMRIScript() {
   
   // Nothing to do if not saved.
   if (Saved)
     performOperation(ReplaceOrInsert, &NewMembers);
   exit(0);
 }
 
 static bool handleGenericOption(StringRef arg) {
-  if (arg == "h" || arg.startswith("-h") || arg == "--help") {
+  if (arg == "-help" || arg == "--help") {
     printHelpMessage();
     return true;
   }
   if (arg == "-version" || arg == "--version") {
     cl::PrintVersionMessage();
     return true;
   }
   return false;