Bug 864151 – x11-drivers/xf86-input-vmmouse-13.1.0-r1 fails to compile (lto): xf86_OSproc.h:115:23: error: type of xf86EnableIO does not match original declaration [-Werror=lto-type-mismatch]

• Status: RESOLVED FIXED
• Product: Gentoo Linux

[Description Agostino Sarubbo 2022-08-07 08:17:05 UTC]

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

Issue: x11-drivers/xf86-input-vmmouse-13.1.0-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 2022-08-07 08:17:07 UTC]

Created attachment 798439 [details]
build.log

build log and emerge --info

[Comment 2 Larry the Git Cow 2022-10-08 23:42:15 UTC]

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

https://gitweb.gentoo.org/repo/gentoo.git/commit/?id=4bf1106f932e955d649c6c45c871fa3e7dc89909

commit 4bf1106f932e955d649c6c45c871fa3e7dc89909
Author:     Matt Turner <[e-mail]>
AuthorDate: 2022-10-08 23:40:49 +0000
Commit:     Matt Turner <[e-mail]>
CommitDate: 2022-10-08 23:42:09 +0000

    x11-drivers/xf86-input-vmmouse: Version bump to 13.2.0
    
    Closes: https://bugs.gentoo.org/864151
    Signed-off-by: Matt Turner <[e-mail]>

 x11-drivers/xf86-input-vmmouse/Manifest            |  1 +
 .../xf86-input-vmmouse-13.2.0.ebuild               | 35 ++++++++++++++++++++++
 .../xf86-input-vmmouse-9999.ebuild                 |  6 ++--
 3 files changed, 39 insertions(+), 3 deletions(-)