[Bug bootstrap/41529] LTO configuration should detect if the target is ELF

["rguenther at suse dot de" <gcc-bugzilla at gcc dot gnu dot org>]

------- Comment #12 from rguenther at suse dot de  2010-01-02 13:56 -------
Subject: Re:  LTO configuration should detect if the
 target is ELF

On Sat, 2 Jan 2010, davek at gcc dot gnu dot org wrote:

> ------- Comment #11 from davek at gcc dot gnu dot org  2010-01-02 13:51 -------
> (In reply to comment #10)
> > FAIL: gcc.dg/lto/20081201-2 c_lto_20081201-2_0.o-c_lto_20081201-2_1.o execute
> > -O3 -fwhopr
> > 
> > this means you do not get any LTO optimization (it's really the only test
> > that tests this ....)
> > 
> > So LTO is not working for you.
> 
>   Righto, I'll look at that one first.
> 
>   Are you aware of any structural reason why LTO can't possibly work on a
> non-ELF platform? 

The only part that really relies on native ELF object files is
the mixing of LTO sections with regular object code as produced
by cc1 - lto1 relies on libelf to identify and read the LTO sections,
which probably does not work.

And of course the linker-plugin and symbol resolution stuff done
by it - but the linker-plugin is gold only and ELF only anyway.
The collect2 stuff should in principle work with non-ELF targets
as well if you circumvent that first problem somehow (for
example by not producing regular object code from cc1 but only
assemble the LTO sections to a ELF object file).

Richard.


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=41529