Bug 864763 – x11-misc/xnee-3.19-r2 fails to compile (lto): print.c:181:24: error: dereferencing type-punned pointer will break strict-aliasing rules [-Werror=strict-aliasing]

• Product: Gentoo Linux
• Status: RESOLVED FIXED

[Description Agostino Sarubbo 2022-08-10 06:47:45 UTC]

https://blogs.gentoo.org/ago/2020/07/04/gentoo-tinderbox/

Issue: x11-misc/xnee-3.19-r2 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 2022-08-10 06:47:47 UTC]

Created attachment 799073 [details]
build.log

build log and emerge --info

[Comment 2 Larry the Git Cow 2022-11-14 17:38:20 UTC]

The bug has been referenced in the following commit(s):

https://gitweb.gentoo.org/repo/gentoo.git/commit/?id=0c77aadb983014ccf56fc464d83906c0cf3c3271

commit 0c77aadb983014ccf56fc464d83906c0cf3c3271
Author:     Matt Turner <[e-mail]>
AuthorDate: 2022-11-14 17:36:23 +0000
Commit:     Matt Turner <[e-mail]>
CommitDate: 2022-11-14 17:38:12 +0000

    profiles: Mask x11-misc/xnee for removal
    
    Bug: https://bugs.gentoo.org/812137
    Bug: https://bugs.gentoo.org/864763
    Bug: https://bugs.gentoo.org/871405
    Bug: https://bugs.gentoo.org/873886
    Signed-off-by: Matt Turner <[e-mail]>

 profiles/package.mask | 8 ++++++++
 1 file changed, 8 insertions(+)

[Comment 3 Larry the Git Cow 2022-12-14 03:14:17 UTC]

The bug has been closed via the following commit(s):

https://gitweb.gentoo.org/repo/gentoo.git/commit/?id=c4f4ac8bdd220056f74da4218c7385a1f755680d

commit c4f4ac8bdd220056f74da4218c7385a1f755680d
Author:     Matt Turner <[e-mail]>
AuthorDate: 2022-12-14 03:12:16 +0000
Commit:     Matt Turner <[e-mail]>
CommitDate: 2022-12-14 03:14:01 +0000

    x11-misc/xnee: Delete
    
    Closes: https://bugs.gentoo.org/812137
    Closes: https://bugs.gentoo.org/864763
    Closes: https://bugs.gentoo.org/871405
    Closes: https://bugs.gentoo.org/873886
    Signed-off-by: Matt Turner <[e-mail]>

 profiles/package.mask                              |   8 --
 x11-misc/xnee/Manifest                             |   1 -
 x11-misc/xnee/files/xnee-3.18-linker.patch         |  10 --
 .../xnee-3.19-libgnomeui-only-for-applets.patch    | 117 ---------------------
 x11-misc/xnee/files/xnee-3.19-slibtool.patch       |  19 ----
 x11-misc/xnee/metadata.xml                         |   8 --
 x11-misc/xnee/xnee-3.19-r2.ebuild                  |  80 --------------
 7 files changed, 243 deletions(-)