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Bug 854876 - app-shells/squirrelsh-1.2.7-r1 fails to compile (lto): sqcompiler.cpp:872:69: error: dereferencing type-punned pointer will break strict-aliasing rules [-Werror=strict-aliasing]
Summary: app-shells/squirrelsh-1.2.7-r1 fails to compile (lto): sqcompiler.cpp:872:69:...
Status: RESOLVED FIXED
Alias: None
Product: Gentoo Linux
Classification: Unclassified
Component: Current packages (show other bugs)
Hardware: All Linux
: Normal normal
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
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Reported: 2022-06-28 15:07 UTC by Agostino Sarubbo
Modified: 2024-03-05 06:54 UTC (History)
0 users

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


Attachments
build.log (build.log,49.65 KB, text/plain)
2022-06-28 15:07 UTC, Agostino Sarubbo
Details

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Description Agostino Sarubbo gentoo-dev 2022-06-28 15:07:37 UTC
https://blogs.gentoo.org/ago/2020/07/04/gentoo-tinderbox/

Issue: app-shells/squirrelsh-1.2.7 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 15:07:39 UTC
Created attachment 788504 [details]
build.log

build log and emerge --info
Comment 2 Agostino Sarubbo gentoo-dev 2022-07-26 09:00:28 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 Agostino Sarubbo gentoo-dev 2024-02-14 08:07:13 UTC
lto_tinderbox has reproduced this issue with version 1.2.7-r1 - Updating summary.
Comment 4 Larry the Git Cow gentoo-dev 2024-03-05 06:54:35 UTC
The bug has been closed via the following commit(s):

https://gitweb.gentoo.org/repo/gentoo.git/commit/?id=66fa14432a9b1ee68e3d869e6d1067c2887b0bcd

commit 66fa14432a9b1ee68e3d869e6d1067c2887b0bcd
Author:     Sam James <sam@gentoo.org>
AuthorDate: 2024-03-05 06:52:20 +0000
Commit:     Sam James <sam@gentoo.org>
CommitDate: 2024-03-05 06:52:38 +0000

    app-shells/squirrelsh: filter LTO, no SA
    
    Dead upstream and marked inactive on sourceforge.
    
    At some point, IIRC, we hit this in a package too which bundles squirrelsh.
    
    Closes: https://bugs.gentoo.org/854876
    Signed-off-by: Sam James <sam@gentoo.org>

 app-shells/squirrelsh/squirrelsh-1.2.7-r1.ebuild | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)