[PATCH v2] Improve building with LTO

[Martin Liška]

On 11/9/21 12:45, Mark Wielaard wrote:
> Hi Martin,
> 
> On Tue, 2021-11-09 at 10:04 +0100, Martin Liška wrote:
>> On 11/9/21 09:58, Dmitry V. Levin wrote:
>>> Yes, but those who build elfutils with -flto are likely using
>>> -ffat-lto-objects if they build static libraries.
>>
>> Yes, I can confirm that we do that as openSUSE, we actually build
>> with:
>>
>> -flto -flto-partition=none -Wno-error=stack-usage= -ffat-lto-objects
> 
> As Dmitry pointed out you should now be able to drop both -flto-
> partition=none an -Wno-error=stack-usage= (the linker will still warn,
> but not error on the large stack-usage issues (we should probably still
> fix them though).

Correct, I'm not using:
F="-O2 -g -Wall -flto=auto -ffat-lto-objects" && export CFLAGS="$F" && export CXXFLAGS="$F" && export LDFLAGS="$F" && ./configure


> 
> What do the test results look like? Do they all PASS with -ffat-lto-
> objects?
> 
> Could you try the proposed patch for
> https://sourceware.org/bugzilla/show_bug.cgi?id=27367
> https://sourceware.org/pipermail/elfutils-devel/2021q4/004314.html

With the suggested patch (and BFD) all is green and shiny:

============================================================================
Testsuite summary for elfutils 0.185
============================================================================
# TOTAL: 252
# PASS:  249
# SKIP:  3
# XFAIL: 0
# FAIL:  0
# XPASS: 0
# ERROR: 0

Cheers,
Martin

> 
> Thanks,
> 
> Mark
>