Bug 862708 – sci-libs/gloo-2022.05.18 fails to compile (lto): device.cc:151:39: error: aggregate std::array<char, 64> hostname has incomplete type and cannot be defined

• Product: Gentoo Linux
• Status: RESOLVED FIXED

[Description Agostino Sarubbo 2022-08-01 07:56:14 UTC]

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

Issue: sci-libs/gloo-2022.05.18 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 2022-08-01 07:56:16 UTC]

Created attachment 796450 [details]
build.log

build log and emerge --info

[Comment 2 Agostino Sarubbo 2022-08-01 07:56:18 UTC]

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


FAILED: gloo/CMakeFiles/gloo.dir/transport/tcp/device.cc.o 
FAILED: gloo/CMakeFiles/gloo.dir/transport/tcp/tls/pair.cc.o 
/var/tmp/portage/sci-libs/gloo-2022.05.18/work/gloo-5b143513263133af2b95547e97c07cebeb72bf72/gloo/transport/tcp/device.cc:151:39: error: aggregate ‘std::array<char, 64> hostname’ has incomplete type and cannot be defined

[Comment 3 Larry the Git Cow 2022-08-02 09:31:40 UTC]

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

https://gitweb.gentoo.org/repo/gentoo.git/commit/?id=13b65d9818c00d785c957612a8e22d82dcd12e43

commit 13b65d9818c00d785c957612a8e22d82dcd12e43
Author:     Alfredo Tupone <[e-mail]>
AuthorDate: 2022-08-02 09:31:13 +0000
Commit:     Alfredo Tupone <[e-mail]>
CommitDate: 2022-08-02 09:31:13 +0000

    sci-libs/gloo: possibly fix missing header
    
    Closes: https://bugs.gentoo.org/862708
    Package-Manager: Portage-3.0.30, Repoman-3.0.3
    Signed-off-by: Alfredo Tupone <[e-mail]>

 sci-libs/gloo/files/gloo-2022.05.18-gentoo.patch | 10 ++++++++++
 1 file changed, 10 insertions(+)