Bug 865997

Summary:	app-text/blogc-0.20.1 fails tests (lto): <artificial>:(.text+0x84): undefined reference to __wrap_bc_file_get_contents
Product:	Gentoo Linux	Reporter:	Agostino Sarubbo <ago>
Component:	Current packages	Assignee:	No maintainer - Look at https://wiki.gentoo.org/wiki/Project:Proxy_Maintainers if you want to take care of it <maintainer-needed>
Status:	RESOLVED WORKSFORME
Severity:	normal	CC:	eschwartz, treecleaner
Priority:	Normal
Version:	unspecified
Hardware:	All
OS:	Linux
See Also:	https://bugs.gentoo.org/show_bug.cgi?id=877741
Whiteboard:
Package list:		Runtime testing required:	---
Bug Depends on:
Bug Blocks:	618550
Attachments:	build.log

Description Agostino Sarubbo gentoo-dev

2022-08-22 07:47:14 UTC

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

Issue: app-text/blogc-0.20.1 fails tests (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 gentoo-dev

2022-08-22 07:47:16 UTC

Created attachment 800403 [details]
build.log

build log and emerge --info

Comment 2 Agostino Sarubbo gentoo-dev

2022-08-22 07:47:18 UTC

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


<artificial>:(.text+0x444): undefined reference to `__wrap_bc_file_get_contents'
<artificial>:(.text+0x49): undefined reference to `__wrap_bc_file_get_contents'
<artificial>:(.text+0x53ed): undefined reference to `__wrap_bc_file_get_contents'
<artificial>:(.text+0x84): undefined reference to `__wrap_bc_file_get_contents'
<artificial>:(.text+0xa44): undefined reference to `__wrap_bc_file_get_contents'
collect2: error: ld returned 1 exit status

Comment 3 Eli Schwartz gentoo-dev

2024-03-17 08:12:54 UTC

Cannot reproduce.