Gentoo Websites Logo
Go to: Gentoo Home Documentation Forums Lists Bugs Planet Store Wiki Get Gentoo!
Bug 863269 - sci-mathematics/vampire-4.7 fails to compile (lto): SkipList.hpp:523:56: error: dereferencing type-punned pointer will break strict-aliasing rules [-Werror=strict-aliasing]
Summary: sci-mathematics/vampire-4.7 fails to compile (lto): SkipList.hpp:523:56: erro...
Status: RESOLVED FIXED
Alias: None
Product: Gentoo Linux
Classification: Unclassified
Component: Current packages (show other bugs)
Hardware: All Linux
: Normal normal (vote)
Assignee: Gentoo Science Mathematics related packages
URL:
Whiteboard:
Keywords:
Depends on:
Blocks: lto
  Show dependency tree
 
Reported: 2022-08-03 07:01 UTC by Agostino Sarubbo
Modified: 2022-08-06 23:53 UTC (History)
0 users

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


Attachments
build.log (build.log,125.03 KB, text/plain)
2022-08-03 07:01 UTC, Agostino Sarubbo
Details

Note You need to log in before you can comment on or make changes to this bug.
Description Agostino Sarubbo gentoo-dev 2022-08-03 07:01:32 UTC
https://blogs.gentoo.org/ago/2020/07/04/gentoo-tinderbox/

Issue: sci-mathematics/vampire-4.7 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

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 2022-08-03 07:01:35 UTC
Created attachment 797140 [details]
build.log

build log and emerge --info
Comment 2 Agostino Sarubbo gentoo-dev 2022-08-03 07:01:37 UTC
Error(s) that match a know pattern in addition to what has been reported in the summary:


FAILED: CMakeFiles/obj.dir/Indexing/SubstitutionTree_FastGen.cpp.o 
FAILED: CMakeFiles/obj.dir/Indexing/SubstitutionTree_FastInst.cpp.o 
fatal: not a git repository (or any parent up to mount point /var/tmp)
/var/tmp/portage/sci-mathematics/vampire-4.7/work/vampire-2d02e4655e1b08d1ca9ee7c0aade40f59f046460/Lib/SkipList.hpp:523:56: error: dereferencing type-punned pointer will break strict-aliasing rules [-Werror=strict-aliasing]
Comment 3 Larry the Git Cow gentoo-dev 2022-08-06 23:53:12 UTC
The bug has been closed via the following commit(s):

https://gitweb.gentoo.org/repo/gentoo.git/commit/?id=c1dc1afc5592077b339f17e00e93b6bc2180f768

commit c1dc1afc5592077b339f17e00e93b6bc2180f768
Author:     Maciej Barć <xgqt@gentoo.org>
AuthorDate: 2022-08-06 23:50:34 +0000
Commit:     Maciej Barć <xgqt@gentoo.org>
CommitDate: 2022-08-06 23:51:56 +0000

    sci-mathematics/vampire: filter LTO (strict-aliasing)
    
    Closes: https://bugs.gentoo.org/863269
    Signed-off-by: Maciej Barć <xgqt@gentoo.org>

 sci-mathematics/vampire/vampire-4.6.1-r1.ebuild | 6 +++++-
 sci-mathematics/vampire/vampire-4.7.ebuild      | 6 +++++-
 2 files changed, 10 insertions(+), 2 deletions(-)