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Bug 862927

Summary: sci-libs/silo-4.11-r1 fails to compile (lto): H5Zzfp.c:357:53: error: dereferencing type-punned pointer will break strict-aliasing rules [-Werror=strict-aliasing]
Product: Gentoo Linux Reporter: Agostino Sarubbo <ago>
Component: Current packagesAssignee: Gentoo Cluster Team <cluster>
Status: RESOLVED FIXED    
Severity: normal    
Priority: Normal    
Version: unspecified   
Hardware: All   
OS: Linux   
Whiteboard:
Package list:
Runtime testing required: ---
Bug Depends on:    
Bug Blocks: 618550    
Attachments: build.log

Description Agostino Sarubbo gentoo-dev 2022-08-02 06:59:50 UTC
https://blogs.gentoo.org/ago/2020/07/04/gentoo-tinderbox/

Issue: sci-libs/silo-4.11-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 2022-08-02 06:59:53 UTC
Created attachment 796774 [details]
build.log

build log and emerge --info
Comment 2 Agostino Sarubbo gentoo-dev 2022-08-02 06:59:56 UTC
Error(s) that match a know pattern in addition to what has been reported in the summary:


checking for Qt... ./configure: line 25712: qmake: command not found
H5Zzfp.c:357:53: error: dereferencing type-punned pointer will break strict-aliasing rules [-Werror=strict-aliasing[https://gcc.gnu.org/onlinedocs/gcc/Warning-Options.html#index-Wstrict-aliasing]]
Comment 3 Larry the Git Cow gentoo-dev 2024-03-17 07:50:19 UTC
The bug has been closed via the following commit(s):

https://gitweb.gentoo.org/repo/gentoo.git/commit/?id=563f6de9fc73190ad10ae3778fe3ede11a42f7e3

commit 563f6de9fc73190ad10ae3778fe3ede11a42f7e3
Author:     Sam James <sam@gentoo.org>
AuthorDate: 2024-03-17 07:48:42 +0000
Commit:     Sam James <sam@gentoo.org>
CommitDate: 2024-03-17 07:49:44 +0000

    sci-libs/silo: add 4.11.1
    
    * Partially fix tests with GCC 14 (reported another issue on the upstream PR for that).
    * Disable LTO and SA given the comments on a linked upstream bug wrt opimisation.
    
    Closes: https://bugs.gentoo.org/862927
    Signed-off-by: Sam James <sam@gentoo.org>

 sci-libs/silo/Manifest                            |  1 +
 sci-libs/silo/files/silo-4.11.1-gcc14-tests.patch | 45 ++++++++++++++++
 sci-libs/silo/silo-4.11.1.ebuild                  | 63 +++++++++++++++++++++++
 3 files changed, 109 insertions(+)