Bug 861464 – net-irc/psybnc-2.3.2.9-r4 fails to compile (lto): p_global.h:952:5: error: type of [-Werror=lto-type-mismatch]

• Product: Gentoo Linux
• Status: RESOLVED FIXED

[Description Agostino Sarubbo 2022-07-27 12:30:27 UTC]

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

Issue: net-irc/psybnc-2.3.2.9-r4 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 2022-07-27 12:30:29 UTC]

Created attachment 794954 [details]
build.log

build log and emerge --info

[Comment 2 Larry the Git Cow 2022-10-24 11:47:01 UTC]

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

https://gitweb.gentoo.org/repo/gentoo.git/commit/?id=94f95c98b33988c57038800875bcb2ce830a67af

commit 94f95c98b33988c57038800875bcb2ce830a67af
Author:     Sam James <[e-mail]>
AuthorDate: 2022-10-24 11:46:29 +0000
Commit:     Sam James <[e-mail]>
CommitDate: 2022-10-24 11:46:29 +0000

    net-irc/psybnc: add 2.4.3
    
    Bug: https://bugs.gentoo.org/724916
    Bug: https://bugs.gentoo.org/831310
    Bug: https://bugs.gentoo.org/861464
    Bug: https://bugs.gentoo.org/874105
    Signed-off-by: Sam James <[e-mail]>

 .../psybnc-2.4.3-Fix-build-with-Clang-16.patch     | 212 +++++++++++++++++++++
 net-irc/psybnc/psybnc-2.4.3.ebuild                 | 165 ++++++++++++++++
 2 files changed, 377 insertions(+)

[Comment 3 Larry the Git Cow 2024-03-12 04:04:14 UTC]

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

https://gitweb.gentoo.org/repo/gentoo.git/commit/?id=dd619923c273bcc95d69be933e30c043b23941d9

commit dd619923c273bcc95d69be933e30c043b23941d9
Author:     Sam James <[e-mail]>
AuthorDate: 2024-03-12 04:03:12 +0000
Commit:     Sam James <[e-mail]>
CommitDate: 2024-03-12 04:03:12 +0000

    net-irc/psybnc: fix build w/ LTO
    
    Closes: https://bugs.gentoo.org/861464
    Signed-off-by: Sam James <[e-mail]>

 .../files/psybnc-2.4.3-strmncpy-lto-mismatch.patch |  23 +++
 net-irc/psybnc/psybnc-2.4.3-r1.ebuild              | 170 +++++++++++++++++++++
 2 files changed, 193 insertions(+)