Re: enabling link time optimizations in package builds

Timo Röhling <[email protected]> Fri, 1 Jul 2022 22:40:03 +0200

Newsgroups	gmane.linux.debian.ports.bsd
Organization	The Debian Project
Message-ID	<20220701204003.vrssxnulga3odb7r__9779.75385483063$1656708577$gmane$org@mail.gaussglocke.de>

Hi Matthias,

* Matthias Klose <[email protected]> [2022-06-17 10:18]:
>The proposal is to turn on LTO by default on most 64bit release 
>architectures. Not proposing to do this on 32bit architectures because 
>of the limited address space at link time, and up to now nobody tested 
>LTO on 32bit archs.  In test rebuilds, there were 373 packages 
>(dd-list in the wiki page) found not to build with link time 
>optimizations for various reasons.  These range from easily fixable 
>issues in symbols files to some upstream issues.  The idea is to fix 
>as many of these as possible, and then change the packaging for the 
>others to just turn off LTO in the package build.

In one of my packages, turning on LTO did not fail the build, but
exposed a dormant static initialization bug, as LTO apparently
messes with the initialization order [1]. I'd expect more bugs of
this kind to come up once LTO is enabled by default.

Cheers
Timo

[1] https://github.com/isl-org/Open3D/issues/4747

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