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Bug 863731 - sys-cluster/legion-23.03.0 fails to compile (lto): mutex.h:49:11: error: type union <anon> violates the C++ One Definition Rule [-Werror=odr]
Summary: sys-cluster/legion-23.03.0 fails to compile (lto): mutex.h:49:11: error: type...
Status: RESOLVED FIXED
Alias: None
Product: Gentoo Linux
Classification: Unclassified
Component: Current packages (show other bugs)
Hardware: All Linux
: Normal normal (vote)
Assignee: Gentoo Cluster Team
URL:
Whiteboard:
Keywords:
Depends on:
Blocks: lto
  Show dependency tree
 
Reported: 2022-08-05 07:10 UTC by Agostino Sarubbo
Modified: 2024-03-29 02:28 UTC (History)
0 users

See Also:
Package list:
Runtime testing required: ---


Attachments
build.log (build.log,508.51 KB, text/plain)
2022-08-05 07:10 UTC, Agostino Sarubbo
Details

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Description Agostino Sarubbo gentoo-dev 2022-08-05 07:10:18 UTC
https://blogs.gentoo.org/ago/2020/07/04/gentoo-tinderbox/

Issue: sys-cluster/legion-21.09.0-r1 fails to compile (lto).
Discovered on: amd64 (internal ref: lto_tinderbox)

NOTE:
This machine uses lto with CFLAGS=-flto -Werror=odr -Werror=lto-type-mismatch -Werror=strict-aliasing

Here is a bit of explanation:

-Werror=lto-type-mismatch:
User to find possible runtime issues in packages. It likely means the package is unsafe to build & use with LTO.
For projects using the same identifier but with different types across different files, they must be fixed to be consistent across the codebase.

-Werror=odr:
Used to find possible runtime issues in packages. These bugs are a problem anyway but may be even worse when combined with LTO. C++ code must comply with the One Definition Rule (ODR) - see https://en.cppreference.com/w/cpp/language/definition#One_Definition_Rule.

-Werror=strict-aliasing:
Used to find possible runtime issues in packages. These bugs are a problem anyway but may be even worse when combined with LTO.

Workarounds:
- If upstream is friendly and still active, file a bug upstream. For emulators, codecs, games, or multimedia packages, it may be worth just applying a workaround instead, as upstreams sometimes aren't receptive to these bugs (VALID FOR ALL).
- Use the new 'filter-lto' from flag-o-matic.eclass as it's likely to be unsafe with LTO (VALID FOR lto-type-mismatch - odr).
- Fix it yourself if interested, of course (VALID FOR ALL).
- Append-flags -fno-strict-aliasing (VALID FOR strict-aliasing).
- Use memcpy() but a union is sometimes suitable too (VALID FOR strict-aliasing).
- -fstrict-aliasing is implied by -O2, so this must be addressed in some form (VALID FOR strict-aliasing).

See also: https://marc.info/?l=gentoo-dev&m=165639574126280&w=2
Comment 1 Agostino Sarubbo gentoo-dev 2022-08-05 07:10:20 UTC
Created attachment 797833 [details]
build.log

build log and emerge --info
Comment 2 Agostino Sarubbo gentoo-dev 2022-08-05 07:10:23 UTC
Error(s) that match a know pattern in addition to what has been reported in the summary:


FAILED: lib/librealm.so.1 
/var/tmp/portage/sys-cluster/legion-21.09.0-r1/work/legion-legion-21.09.0/runtime/realm/mutex.h:49:11: error: type ‘union <anon>’ violates the C++ One Definition Rule [-Werror=odr]
Comment 3 Agostino Sarubbo gentoo-dev 2024-03-27 08:02:15 UTC
lto_tinderbox has reproduced this issue with version 23.03.0 - Updating summary.
Comment 4 Larry the Git Cow gentoo-dev 2024-03-29 02:28:54 UTC
The bug has been closed via the following commit(s):

https://gitweb.gentoo.org/repo/gentoo.git/commit/?id=8a06e29b72c23a556efa9cd44ca232bf9d3f16e5

commit 8a06e29b72c23a556efa9cd44ca232bf9d3f16e5
Author:     Eli Schwartz <eschwartz93@gmail.com>
AuthorDate: 2024-03-28 06:47:53 +0000
Commit:     Sam James <sam@gentoo.org>
CommitDate: 2024-03-29 02:28:25 +0000

    sys-cluster/legion: mark as LTO-unsafe
    
    Intentionally omitted from live ebuild since it works in git master.
    
    Closes: https://bugs.gentoo.org/863731
    Signed-off-by: Eli Schwartz <eschwartz93@gmail.com>
    Signed-off-by: Sam James <sam@gentoo.org>

 sys-cluster/legion/legion-21.09.0-r1.ebuild | 7 ++++++-
 sys-cluster/legion/legion-23.03.0.ebuild    | 7 ++++++-
 2 files changed, 12 insertions(+), 2 deletions(-)