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

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`.

Reviewers: MaskRay, gbreynoo

Subscribers: llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D69007

llvm-svn: 375028

Author: rupprecht

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

@@ -1,5 +1,10 @@
+## 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
 

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

@@ -0,0 +1,11 @@
+## 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

@@ -100,6 +100,7 @@ USAGE: llvm-ar [options] [-]<operation>[modifiers] [relpos] [count] <archive> [f
   [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
@@ -112,6 +113,7 @@ USAGE: llvm-ar [options] [-]<operation>[modifiers] [relpos] [count] <archive> [f
   [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() {
@@ -381,6 +383,12 @@ static ArchiveOperation parseCommandLine() {
     case 'L':
       AddLibrary = true;
       break;
+    case 'V':
+      cl::PrintVersionMessage();
+      exit(0);
+    case 'h':
+      printHelpMessage();
+      exit(0);
     default:
       fail(std::string("unknown option ") + Options[i]);
     }
@@ -1063,7 +1071,7 @@ static void runMRIScript() {
 }
 
 static bool handleGenericOption(StringRef arg) {
-  if (arg == "h" || arg.startswith("-h") || arg == "--help") {
+  if (arg == "-help" || arg == "--help") {
     printHelpMessage();
     return true;
   }