[llvm-objcopy] Hook up the -V alias to --version, output "GNU strip"

[mstorsjo]

Summary

This allows libtool to detect the presence of llvm-strip and use it with the options --strip-debug and --strip-unneeded, see http://git.savannah.gnu.org/cgit/libtool.git/tree/m4/libtool.m4?h=v2.4.6#n2210.

Also hook up the -V alias for objcopy.

[jhenderson]

Should we do the same thing (adding "comptabile with GNU objcopy") for llvm-objcopy as well as llvm-strip?

test/tools/llvm-objcopy/strip-version.test

5

This should probably check both {{version}} and "GNU strip", right?

[mstorsjo]

In D54936#1309342, @jhenderson wrote:

Should we do the same thing (adding "comptabile with GNU objcopy") for llvm-objcopy as well as llvm-strip?

I don't know of any build system that checks for that in the output, but I guess we could do that for consistency.

test/tools/llvm-objcopy/strip-version.test

5

Right, I can keep that check as well. Will update the patch in a few hours.

[mstorsjo]

Changed to keep the check for {{ version }} in the llvm-strip output, outputting "compatible with GNU objcopy" as well (but no test for that as I haven't seen a specific need for that string somewhere yet).

[jhenderson]

I think it would make sense to test in both cases, honestly, but I'm not too fussed.

Otherwise, LGTM.

You might want to wait on @jakehehrlich to give his opinion on "GNU compatible" output in both tools before committing.

[jakehehrlich]

I think this is fine. GNU compatibility is a tricky subject with lots of nuances that I keep discovering but it is decidedly a stated goal.

[jakehehrlich]

LGTM

test/tools/llvm-objcopy/objcopy-version.test

 # RUN: llvm-objcopy -version | FileCheck %s
 # RUN: llvm-objcopy --version | FileCheck %s
+# RUN: llvm-objcopy -V | FileCheck %s
 
 # CHECK: {{ version }}

test/tools/llvm-objcopy/strip-version.test

 # RUN: llvm-strip -version | FileCheck %s
 # RUN: llvm-strip --version | FileCheck %s
+# RUN: llvm-strip -V | FileCheck %s
 
-# CHECK: {{ version }}
+# CHECK: GNU strip

tools/llvm-objcopy/CopyConfig.cpp

DriverConfig parseStripOptions(ArrayRef<const char *> ArgsArr) {
   }
 
   if (InputArgs.hasArg(STRIP_help)) {
     T.PrintHelp(outs(), "llvm-strip [options] file...", "strip tool");
     exit(0);
   }
 
   if (InputArgs.hasArg(STRIP_version)) {
+    outs() << "llvm-strip, compatible with GNU strip\n";
     cl::PrintVersionMessage();
     exit(0);
   }
 
   SmallVector<const char *, 2> Positional;
   for (auto Arg : InputArgs.filtered(STRIP_UNKNOWN))
     error("unknown argument '" + Arg->getAsString(InputArgs) + "'");
   for (auto Arg : InputArgs.filtered(STRIP_INPUT))

tools/llvm-objcopy/ObjcopyOpts.td

: Eq<"dump-section",
          "Dump contents of section named <section> into file <file>">,
       MetaVarName<"section=file">;
 defm prefix_symbols
     : Eq<"prefix-symbols", "Add <prefix> to the start of every symbol name">,
       MetaVarName<"prefix">;
 
 def version : Flag<["-", "--"], "version">,
               HelpText<"Print the version and exit.">;
+def V : Flag<["-"], "V">, Alias<version>;

tools/llvm-objcopy/StripOpts.td

 
 def discard_all
     : Flag<["-", "--"], "discard-all">,
       HelpText<"Remove all local symbols except file and section symbols">;
 def x : Flag<["-"], "x">, Alias<discard_all>;
 
 def version : Flag<["-", "--"], "version">,
               HelpText<"Print the version and exit.">;
+def V : Flag<["-"], "V">, Alias<version>;