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Bug 854906 - app-text/groonga-8.0.2-r1 fails to compile (lto): index_column.c:298:50: error: dereferencing type-punned pointer might break strict-aliasing rules [-Werror=strict-aliasing]
Summary: app-text/groonga-8.0.2-r1 fails to compile (lto): index_column.c:298:50: erro...
Status: CONFIRMED
Alias: None
Product: Gentoo Linux
Classification: Unclassified
Component: Current packages (show other bugs)
Hardware: All Linux
: Normal normal (vote)
Assignee: No maintainer - Look at https://wiki.gentoo.org/wiki/Project:Proxy_Maintainers if you want to take care of it
URL:
Whiteboard:
Keywords:
Depends on:
Blocks: lto
  Show dependency tree
 
Reported: 2022-06-28 18:21 UTC by Agostino Sarubbo
Modified: 2023-04-10 09:25 UTC (History)
0 users

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


Attachments
build.log (build.log,333.23 KB, text/plain)
2022-06-28 18:21 UTC, Agostino Sarubbo
Details

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Description Agostino Sarubbo gentoo-dev 2022-06-28 18:21:33 UTC
https://blogs.gentoo.org/ago/2020/07/04/gentoo-tinderbox/

Issue: app-text/groonga-8.0.2-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
Comment 1 Agostino Sarubbo gentoo-dev 2022-06-28 18:21:35 UTC
Created attachment 788537 [details]
build.log

build log and emerge --info
Comment 2 Agostino Sarubbo gentoo-dev 2022-07-26 09:00:32 UTC
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 3 Larry the Git Cow gentoo-dev 2023-04-10 09:25:23 UTC
The bug has been referenced in the following commit(s):

https://gitweb.gentoo.org/repo/gentoo.git/commit/?id=8c3bf1cd0b4ef023f287da8d8336ba8bbf5166e0

commit 8c3bf1cd0b4ef023f287da8d8336ba8bbf5166e0
Author:     Sam James <sam@gentoo.org>
AuthorDate: 2023-04-10 09:20:42 +0000
Commit:     Sam James <sam@gentoo.org>
CommitDate: 2023-04-10 09:21:26 +0000

    app-text/groonga: add 13.0.1
    
    Bug: https://bugs.gentoo.org/830159
    Bug: https://bugs.gentoo.org/854906
    Closes: https://bugs.gentoo.org/625356
    Closes: https://bugs.gentoo.org/791226
    Closes: https://bugs.gentoo.org/800620
    Closes: https://bugs.gentoo.org/806091
    Closes: https://bugs.gentoo.org/829105
    Closes: https://bugs.gentoo.org/903659
    Signed-off-by: Sam James <sam@gentoo.org>

 app-text/groonga/Manifest              |   1 +
 app-text/groonga/groonga-13.0.1.ebuild | 107 +++++++++++++++++++++++++++++++++
 2 files changed, 108 insertions(+)