[lld/mac] Add --version flag

[thakis]

Summary

It's an extension to ld64, but all the other ports have it, and
someone asked for it in PR43721.

While here, change the COFF help text to match the other ports.

[int3]

lld/MachO/Driver.cpp

768–769

I assume that -- unlike for -v -- we're intentionally not printing out the library/framework search paths for --version... could we update the help text to indicate how -v differs? Also, how about handling OPT_version here, next to OPT_v, just to co-locate similar logic?

lld/MachO/Options.td

513–515

I think it'd make sense to put the flag here under grp_rare

[thakis]

Thanks!

lld/MachO/Driver.cpp

768–769

The other ports have --version up top, before doing any other flag pcoessing. -v has to do flag processing to get the search paths, but --version doesn't, so I'd prefer to keep it up there. Updated the help text for -v.

lld/MachO/Options.td

513–515

Currently all the non-ld64 flags are up top under the Flags that lld/MachO understands but ld64 doesn't comment. Want to to add Group<grp_rare> up there?

[thakis]

tweak -v help text

[int3]

lld/MachO/Driver.cpp

768–769

fair enough

lld/MachO/Options.td

513–515

hmm I guess we can leave it as-is. maybe we should make a group specifically for lld-specific options?

[thakis]

Thanks!

lld/MachO/Options.td

513–515

I think that's a good idea.

[rupprecht]

lld/test/MachO/driver.test

2

FYI, this test is overly specific; be89d7460b63508a6a277050395c14a4fa74b031 to fix this.

For comparison, the --version check from lld/test/ELF/driver.test:

# RUN: ld.lld --version 2>&1 | FileCheck -check-prefix=VERSION %s
# RUN: ld.lld -v 2>&1 | FileCheck -check-prefix=VERSION %s
# RUN: not ld.lld -v xyz 2>&1 | FileCheck -check-prefix=VERSION %s
# VERSION: LLD {{.*}} (compatible with GNU linkers)

lld/COFF/Options.td

def thinlto_object_suffix_replace : P<
     "'old;new' replace old suffix with new suffix in ThinLTO index">;
 def thinlto_prefix_replace: P<
     "thinlto-prefix-replace",
     "'old;new' replace old prefix with new prefix in ThinLTO outputs">;
 def lto_obj_path : P<
     "lto-obj-path",
     "output native object for merged LTO unit to this path">;
 def dash_dash_version : Flag<["--"], "version">,
-  HelpText<"Print version information">;
+  HelpText<"Display the version number and exit">;
 def threads
     : P<"threads", "Number of threads. '1' disables multi-threading. By "
                    "default all available hardware threads are used">;
 def call_graph_ordering_file: P<
     "call-graph-ordering-file", 
     "Layout sections to optimize the given callgraph">;
 defm call_graph_profile_sort: B<
     "call-graph-profile-sort",

lld/MachO/Driver.cpp

bool macho::link(llvm::ArrayRef<const char *> argsArr, bool canExitEarly,
   errorHandler().cleanupCallback = []() { freeArena(); };
 
   MachOOptTable parser;
   opt::InputArgList args = parser.parse(argsArr.slice(1));
 
   if (args.hasArg(OPT_help_hidden)) {
     parser.printHelp(argsArr[0], /*showHidden=*/true);
     return true;
-  } else if (args.hasArg(OPT_help)) {
+  }
+  if (args.hasArg(OPT_help)) {
     parser.printHelp(argsArr[0], /*showHidden=*/false);
     return true;
   }
+  if (args.hasArg(OPT_version)) {
+    message(getLLDVersion());
+    return true;
+  }
 
   if (const char *path = getReproduceOption(args)) {
     // Note that --reproduce is a debug option so you can ignore it
     // if you are trying to understand the whole picture of the code.
     Expected<std::unique_ptr<TarWriter>> errOrWriter =
         TarWriter::create(path, path::stem(path));
     if (errOrWriter) {
       tar = std::move(*errOrWriter);
config->searchDylibsFirst =
         (arg && arg->getOption().getID() == OPT_search_dylibs_first);
 
   config->dylibCompatibilityVersion =
       parseDylibVersion(args, OPT_compatibility_version);
   config->dylibCurrentVersion = parseDylibVersion(args, OPT_current_version);
 
   config->saveTemps = args.hasArg(OPT_save_temps);
 
   if (args.hasArg(OPT_v)) {
     message(getLLDVersion());
     message(StringRef("Library search paths:") +
             (config->librarySearchPaths.size()
                  ? "\n\t" + llvm::join(config->librarySearchPaths, "\n\t")
                  : ""));
     message(StringRef("Framework search paths:") +
             (config->frameworkSearchPaths.size()
                  ? "\n\t" + llvm::join(config->frameworkSearchPaths, "\n\t")
                  : ""));

lld/MachO/Options.td

def no_color_diagnostics: Flag<["--"], "no-color-diagnostics">,
   HelpText<"Alias for --color-diagnostics=never">;
 def color_diagnostics_eq: Joined<["--"], "color-diagnostics=">,
   HelpText<"Use colors in diagnostics (default: auto)">,
   MetaVarName<"[auto,always,never]">;
 def reproduce: Separate<["--"], "reproduce">;
 def reproduce_eq: Joined<["--"], "reproduce=">,
     Alias<!cast<Separate>(reproduce)>,
     HelpText<"Write tar file containing inputs and command to reproduce link">;
+def version: Flag<["--"], "version">,
+    HelpText<"Display the version number and exit">;
 
 
 // This is a complete Options.td compiled from Apple's ld(1) manpage
 // dated 2018-03-07 and cross checked with ld64 source code in repo
 // https://github.com/apple-opensource/ld64 at git tag "512.4" dated
 // 2018-03-18.
 
 // Flags<[HelpHidden]> marks options that are not yet ported to lld,

 def bitcode_symbol_map : Separate<["-"], "bitcode_symbol_map">,
      MetaVarName<"<path>">,
      HelpText<"Write the bitcode symbol reverse mapping to file <path>, or if a directory, to <path>/UUID.bcsymbolmap">,
      Flags<[HelpHidden]>,
      Group<grp_bitcode>;
 
 def grp_rare : OptionGroup<"rare">, HelpText<"RARELY USED">;
 
 def v : Flag<["-"], "v">,
      HelpText<"Print the linker version">,
      Group<grp_rare>;
 def version_details : Flag<["-"], "version_details">,
      HelpText<"Print the linker version in JSON form">,
      Flags<[HelpHidden]>,
      Group<grp_rare>;
 def no_weak_imports : Flag<["-"], "no_weak_imports">,
      HelpText<"Fail if any symbols are weak imports, allowed to be NULL at runtime">,
      Flags<[HelpHidden]>,
      Group<grp_rare>;

lld/test/MachO/driver.test

-# RUN: not %lld ---help 2>&1 | FileCheck -check-prefix=SPELLHELP %s
+# RUN: %lld --version | FileCheck -check-prefix=VERSION %s
+VERSION: {{LLD [0-9]+\.[0-9]+}}
 
+# RUN: not %lld ---help 2>&1 | FileCheck -check-prefix=SPELLHELP %s
 SPELLHELP: error: unknown argument '---help', did you mean '--help'
 # FIXME: This should say "no input files" instead
 SPELLHELP: error: undefined symbol: _main