Bug 855674 – dev-libs/criterion-2.4.1 fails to compile (lto): exe-elf.c:151:12: error: type of main does not match original declaration [-Werror=lto-type-mismatch]

• Product: Gentoo Linux
• Status: RESOLVED FIXED

[Description Agostino Sarubbo 2022-07-02 07:22:11 UTC]

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

Issue: dev-libs/criterion-2.4.1 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 2022-07-02 07:22:14 UTC]

Created attachment 789440 [details]
build.log

build log and emerge --info

[Comment 2 Agostino Sarubbo 2022-07-02 07:22:16 UTC]

Error(s) that match a know pattern in addition to what has been reported in the summary:


FAILED: src/libcriterion.so.3.2.0 
Library intl found: NO
Run-time dependency nanopb found: NO (tried cmake)
../../../boxfort-0.1.4/work/boxfort-0.1.4-build/../BoxFort-0.1.4/src/exe-elf.c:151:12: error: type of ‘main’ does not match original declaration [-Werror=lto-type-mismatch]

[Comment 3 Agostino Sarubbo 2022-07-26 09:00:55 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 4 Larry the Git Cow 2024-03-11 14:23:59 UTC]

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

https://gitweb.gentoo.org/repo/gentoo.git/commit/?id=a64c06e48051b343892531c89d15095c3ee9d8f8

commit a64c06e48051b343892531c89d15095c3ee9d8f8
Author:     Eli Schwartz <[e-mail]>
AuthorDate: 2024-03-10 21:00:26 +0000
Commit:     Sam James <[e-mail]>
CommitDate: 2024-03-11 14:22:42 +0000

    dev-libs/criterion: mark as LTO-unsafe
    
    Closes: https://bugs.gentoo.org/855674
    Signed-off-by: Eli Schwartz <[e-mail]>
    Signed-off-by: Sam James <[e-mail]>

 dev-libs/criterion/criterion-2.4.1.ebuild | 5 +++++
 1 file changed, 5 insertions(+)