[ELF] - exit on --version call

[grimar]

Summary

Sorry for posting such a minor one
, but just found I am not sure this is
expected behaviour though it seems so according to
https://llvm.org/bugs/show_bug.cgi?id=31057.

So do we want that one right ?

[davide]

The patch is correct, but please add a testcase.

[grimar]

• Updated test.

[grimar]

In D26865#600142, @davide wrote:

The patch is correct, but please add a testcase.

I missed I need to update test as well, thanks !

[ruiu]

This is the patch I mentioned. http://llvm.org/viewvc/llvm-project?view=revision&revision=278797

[emaste]

Seems it's a difference in behaviour between -v and --version. AFAICT for -v both ld.bfd and ld.gold print a one-line version number and carry on with the link if there are args (or exit with 0 if not). For --version they print a multi-line version & This program is free software info, and do not link.

[ruiu]

So we probably should stop handling --version as an alias to -v and make --verbose behave differently than -v.

[grimar]

In D26865#600168, @ruiu wrote:

This is the patch I mentioned. http://llvm.org/viewvc/llvm-project?view=revision&revision=278797

Hmm, I really forgot about this one. Confusing.

[grimar]

In D26865#600186, @ruiu wrote:

So we probably should stop handling --version as an alias to -v and make --verbose behave differently than -v.

I can do that tomorrow. (if nobody needs to fix it faster).

[grimar]

• Updated.

Behavior of ld.bfd and ld.gold is inconsistent. I checked the next combinations:
ld -v + <normal files>. Result: link OK.
gold -v + <normal files>. Result: link OK.
ld -v <no files>. Result: exit with code 0.
gold -v <no files>. Result: exit with code 0.
ld -version <no files>. Result: exit with code 0.
gold -version <no files>. Result: exit with code 0.

Until here behavior was equal. But the last case has different result:
ld -version <normal files>. Result: no link happens, exit with 0.
gold -version <normal file>. Result: link OK.

That is what Rui mentioned on bug page, I did not realized it at first.

So looks we can live with just a minor change like this patch do to fix
PR31057, thoughts ?

[ruiu]

LGTM

ELF/Driver.cpp

 
 void LinkerDriver::main(ArrayRef<const char *> ArgsArr, bool CanExitEarly) {
   ELFOptTable Parser;
   opt::InputArgList Args = Parser.parse(ArgsArr.slice(1));
   if (Args.hasArg(OPT_help)) {
     printHelp(ArgsArr[0]);
     return;
   }
-  if (Args.hasArg(OPT_version))
+
+  // GNU linkers disagree here. Though both -version and -v are mentioned
+  // in help to print the version information, GNU ld just normally exits,
+  // while gold can continue linking. We are compatible with ld.bfd here.
+  if (Args.hasArg(OPT_version) || Args.hasArg(OPT_v))
     outs() << getLLDVersion() << "\n";
+  if (Args.hasArg(OPT_version))
+    return;
+
   Config->ExitEarly = CanExitEarly && !Args.hasArg(OPT_full_shutdown);
 
   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.
     ErrorOr<CpioFile *> F = CpioFile::create(Path);
     if (F) {
       Cpio.reset(*F);

ELF/Options.td

def undefined: S<"undefined">,
   HelpText<"Force undefined symbol during linking">;
 
 def unresolved_symbols: J<"unresolved-symbols=">,
   HelpText<"Determine how to handle unresolved symbols">;
 
 def rsp_quoting: J<"rsp-quoting=">,
   HelpText<"Quoting style for response files. Values supported: windows|posix">;
 
+def v: Flag<["-"], "v">, HelpText<"Display the version number">;
+
 def verbose: F<"verbose">, HelpText<"Verbose mode">;
 
-def version: F<"version">, HelpText<"Display the version number">;
+def version: F<"version">, HelpText<"Display the version number and exit">;
 
 def version_script: S<"version-script">,
   HelpText<"Read a version script">;
 
 def warn_common: F<"warn-common">,
   HelpText<"Warn about duplicate common symbols">;
 
 def whole_archive: F<"whole-archive">,

 def alias_Tbss: J<"Tbss=">, Alias<Tbss>;
 def alias_Tdata: J<"Tdata=">, Alias<Tdata>;
 def alias_trace: Flag<["-"], "t">, Alias<trace>;
 def alias_trace_symbol_y : JoinedOrSeparate<["-"], "y">, Alias<trace_symbol>;
 def alias_Ttext: J<"Ttext=">, Alias<Ttext>;
 def alias_undefined_eq: J<"undefined=">, Alias<undefined>;
 def alias_undefined_u: JoinedOrSeparate<["-"], "u">, Alias<undefined>;
 def alias_version_V: Flag<["-"], "V">, Alias<version>;
-def alias_version_v: Flag<["-"], "v">, Alias<version>;
 def alias_wrap_wrap: J<"wrap=">, Alias<wrap>;
 
 // Our symbol resolution algorithm handles symbols in archive files differently
 // than traditional linkers, so we don't need --start-group and --end-group.
 // These options are recongized for compatibility but ignored.
 def end_group: F<"end-group">;
 def end_group_paren: Flag<["-"], ")">;
 def start_group: F<"start-group">;

test/ELF/driver.test

 
 # RUN: llvm-mc -filetype=obj -triple=x86_64-unknown-linux %s -o %t
 # RUN: not ld.lld %t -o /no/such/file 2>&1 | FileCheck -check-prefix=MISSING %s
 # MISSING: failed to open /no/such/file
 
 # RUN: ld.lld --help 2>&1 | FileCheck -check-prefix=HELP %s
 # HELP: USAGE:
 
-# RUN: not ld.lld --version 2>&1 | FileCheck -check-prefix=VERSION %s
+# RUN: ld.lld --version 2>&1 | FileCheck -check-prefix=VERSION %s
 # VERSION: LLD
 
+# RUN: not ld.lld -v 2>&1 | FileCheck -check-prefix=VERSION %s
+
 ## Attempt to link DSO with -r
 # RUN: ld.lld -shared %t -o %t.so
 # RUN: not ld.lld -r %t.so %t -o %tfail 2>&1 | FileCheck -check-prefix=ERR %s
 # ERR: attempted static link of dynamic object
 
 ## Attempt to use -r and -shared together
 # RUN: not ld.lld -r -shared %t -o %tfail 2>&1 | FileCheck -check-prefix=ERR2 %s
 # ERR2: -r and -shared may not be used together