[llvm-dev] Embedding LLD version to executables

[Hal Finkel via llvm-dev]

----- Original Message -----
> From: "Mehdi Amini via llvm-dev" <llvm-dev at lists.llvm.org>
> To: "Rui Ueyama" <ruiu at google.com>
> Cc: "llvm-dev" <llvm-dev at lists.llvm.org>
> Sent: Tuesday, October 18, 2016 10:22:00 PM
> Subject: Re: [llvm-dev] Embedding LLD version to executables
> 
> 
> > On Oct 18, 2016, at 6:44 PM, Rui Ueyama via llvm-dev
> > <llvm-dev at lists.llvm.org> wrote:
> > 
> > I'd like to make LLD embed version information so that we can
> > determine if an executable was created by LLD and if that's the
> > case which version of LLD.
> 
> Pardon my ignorance, but what’s the motivation?
> 
> We don’t embed the clang version in every binary clang generates for
> instance.

We do. Clang outputs an "ident" comment with its version information, and that ends up in the object files (at least on Linux).

> 
> > 
> > ld.bfd doesn't seem to embed any information, so we cannot tell
> > whether an executable was linked by ld.bfd or not easily.
> > 
> > ld.gold embeds a string "GNU gold <version>" as
> > ".note.gnu.gold-version" section contents.
> > 
> > I'm wondering what we should do for LLD. The gold's way seems
> > almost right, but I think we don't want to use the same section
> > name because it contains "gold" as part of the section name.
> > However, at the same time, I don't believe we want to create
> > ".note.gnu.lld-version", because if we do, all programs that
> > determine linker version need to look at
> > ".note.gnu.<linker-name>-version" for all known linkers. That's
> > absurd. (Also, our product is not GNU, so ".gnu" part is probably
> > irrelevant.)
> > 
> > I'm leaning towards ".note.linker-version" in hope that other
> > linkers follow it.
> 
> At least that would look much better than a .gnu.xxxx

I agree.

 -Hal

> 
> —
> Mehdi
> 
> 
> _______________________________________________
> LLVM Developers mailing list
> llvm-dev at lists.llvm.org
> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
> 

-- 
Hal Finkel
Lead, Compiler Technology and Programming Languages
Leadership Computing Facility
Argonne National Laboratory