[LLD] Improve --strip-all help text

[bd1976llvm]

Summary

This is a slight improvement to the help text, as I was slightly surprised when --strip-all did more than remove the symbol table.

Currently, we match gold's help text for --strip-all and --strip-debug. I think that the GNU documentation for these options is not particularly clear. However, I have opted to make only a minor change here and keep the help text similar to gold's as these are mature options that are well understood.

[peter.smith]

LGTM. Will be worth waiting before committing to see if there are any comments from MaskRay.

ld.bfd (https://sourceware.org/binutils/docs/ld/Options.html) has a similar implication although it defines strip-debug as a subset of strip-all.

[peter.smith]

Just remembered; worth making the same change in the man page in docs/ld.lld.1 as well.

[bd1976llvm]

Thanks @peter.smith. I have added the man page update.

ld.bfd (https://sourceware.org/binutils/docs/ld/Options.html) has a similar implication although it defines strip-debug as a subset of strip-all.

I think this is the wrong way round as you have to read both the --strip-debug and the --strip-all help text to understand the behaviour of --strip-all, and the --strip-all help text doesn't indicate that he --strip-debug help text is related. I think what I have proposed in this review is better.

[emaste]

lld/docs/ld.lld.1

505 ↗

(On Diff #343048)

FWIW mandoc style (from FreeBSD where this originated) is to start a new sentence on a new line. Not critical, but the rest of this file follows the convention.

[MaskRay]

Looks great!

[bd1976llvm]

Conform to mandoc style.

[bd1976llvm]

lld/docs/ld.lld.1

505 ↗

(On Diff #343048)

Thanks :)

[bd1976llvm]

@tstellar this is a very safe change and we did have a customer confused by this option. Would it be possible to put this change onto the 12 release branch? Thanks.

[tstellar]

Can you file a bug for this?

[bd1976llvm]

In D101890#2741842, @tstellar wrote:

Can you file a bug for this?

https://bugs.llvm.org/show_bug.cgi?id=50264.. I have messaged you about putting this onto the release branch on that bug.

[bd1976llvm]

@tstellar sorry to be a pain but could you give a go or no-go for putting this on the release branch please? For internal reasons I have to finish LLVM 12 changes this week. Thanks!

lld/ELF/Options.td

defm sort_section:
   Eq<"sort-section", "Specifies sections sorting rule when linkerscript is used">;
 
 def start_group: F<"start-group">,
   HelpText<"Ignored for compatibility with GNU unless you pass --warn-backrefs">;
 
 def start_lib: F<"start-lib">,
   HelpText<"Start a grouping of objects that should be treated as if they were together in an archive">;
 
-def strip_all: F<"strip-all">, HelpText<"Strip all symbols">;
+def strip_all: F<"strip-all">, HelpText<"Strip all symbols. Implies --strip-debug">;
 
 def strip_debug: F<"strip-debug">, HelpText<"Strip debugging information">;
 
 defm symbol_ordering_file:
   Eq<"symbol-ordering-file", "Layout sections to place symbols in the order specified by symbol ordering file">;
 
 defm sysroot: Eq<"sysroot", "Set the system root">;