Bug 853901 – dev-python/numpy-1.26.4 fails to compile: f2c_z_lapack.c:29747:33: error: type of xerbla_64_ does not match original declaration [-Werror=lto-type-mismatch]

• Status: CONFIRMED
• Product: Gentoo Linux

[Description Agostino Sarubbo 2022-06-23 16:08:12 UTC]

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

Issue: dev-python/numpy-1.23.0 fails to compile.
Discovered on: amd64 (internal ref: tinderbox)

NOTE:
This machine uses lto with CFLAGS=-flto -Werror=odr -Werror=lto-type-mismatch -Werror=strict-aliasing

[Comment 1 Agostino Sarubbo 2022-06-23 16:08:15 UTC]

Created attachment 787121 [details]
build.log

build log and emerge --info

[Comment 2 Agostino Sarubbo 2022-06-24 07:04:46 UTC]

(In reply to Agostino Sarubbo from comment #0)
> Discovered on: amd64 (internal ref: tinderbox)

internal ref is: lto_tinderbox

[Comment 3 Agostino Sarubbo 2022-07-26 09:00:06 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 Agostino Sarubbo 2022-09-09 13:02:04 UTC]

lto_tinderbox has reproduced this issue with version 1.23.2 - Updating summary.

[Comment 5 Agostino Sarubbo 2024-02-24 07:48:29 UTC]

lto_tinderbox has reproduced this issue with version 1.26.4 - Updating summary.