[PATCH] jit: fix link on OS X and Solaris (PR jit/64089 and PR jit/84288)

[Rainer Orth]

Hi David,

> libgccjit fails to link on OS X and Solaris due to jit/Make-lang.in,
> due to the assumption there that the linker is GNU ld.  Specifically,
> jit/Make-lang.in hardcodes the use of two options: --version-script
> and -soname.
>
> * on Darwin, --version-script doesn't seem to exist in the linker, and
>   it uses -install_name rather than -soname.
>
> * on Solaris, ld doesn't support --version-script.  However, the version
>   script used for libgccjit.so doesn't use any gld extensions, so one can
>   just use -M instead.
>
> This patch fixes these issues by using variables emitted by gcc's "configure"
> rather than hardcoding the options in jit/Make-lang.in.
>
> It's based on the first part of Rainer's patch for PR jit/84288, but I
> made the following changes:
> * the GNU ld case in configure.ac wasn't setting ld_version_script_option.
>   I set it to "--version-script" for that case.

That's weird: the configure.ac part starts with

ld_version_script_option='--version-script'

only overriding it in the Solaris case to keep things for other hosts
as they were.  Besides, I'm pretty sure I tested the patch on Solaris
with gas/gld to make certain that combo continues to work as is...

> * I moved the:
>     LD_VERSION_SCRIPT_OPTION = @ld_version_script_option@
>   from gcc/jit/Make-lang.in to gcc/Makefile.in, as the Make-lang.in files
>   aren't substituted, only the gcc/Makefile.in.
>   Rainer: how did this work for you?

It didn't: what I'd attached to the PR was an initial version of the
patch in the middle between manually hacking gcc/jit/Make-lang.in and
properly autoconfiguring things.

> * added LD_SONAME_OPTION, done in the same way
> * conditionalized the usage of the options in Make-lang.in to cope with
>   empty LD_VERSION_SCRIPT_OPTION (as is presumably the case on OS X).
>   I used ($if condition,then-part[,else-part]) for this.
>   I had to add a $(COMMA) since the "then-part" contains commas, which
>   need to be treated as part of the "then-part", rather than separators
>   for the "else-part".
>   Hopefully this is compatible with every "make" implementation that we
>   support.
>
> Successfully bootstrapped&regrtested on x86_64-pc-linux-gnu.
>
> I lightly tested the not-recognized case by hacking up the configure.ac
> (on x86_64-pc-linux-gnu) and verifying that it links, and that a
> smoketest of jit.dg/test-factorial works.
>
> Does this fix the jit linker issues on OS X and Solaris?

I'll give it a whirl tomorrow, including the jit-recording.c part of my
patch to allow the build to complete.

Thanks.
        Rainer

-- 
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Rainer Orth, Center for Biotechnology, Bielefeld University