Bug 923491

Summary:	media-video/ffmpeg tc-is-lto, filter-lto, and multiple lib issues
Product:	Gentoo Linux	Reporter:	Michael Cook <mackal.cook>
Component:	Current packages	Assignee:	Gentoo Media-video project <media-video>
Status:	UNCONFIRMED ---
Severity:	normal	CC:	floppym, mackal.cook, sam
Priority:	Normal
Version:	unspecified
Hardware:	All
OS:	Linux
See Also:	https://bugs.gentoo.org/show_bug.cgi?id=772854 https://bugs.gentoo.org/show_bug.cgi?id=909572
Whiteboard:
Package list:		Runtime testing required:	---
Bug Depends on:
Bug Blocks:	618550
Attachments:	Fixed ffmpeg ebuild Min-repo ebuild demonstrating issue Min-repo ebuild eclass-debug.log

Description Michael Cook 2024-02-01 21:25:29 UTC

With multilib systems, the 2nd arch run will return false when tc-is-lto is called since filter-lto was called in the previous one.

On my system it builds x86 first, which skips LTO due to previous bugs, but still calls filter-lto which means when it gets to build amd64 tc-is-lto will return false and skip LTO.

I did check an object file with readelf -S when it should have compiled with LTO and it did not. 

I did try moving the LTO stuff to src_prepare (anything only called once before src_configure will work, but I thought it made sense to do it there)

Comment 1 Michael Cook 2024-02-01 21:27:10 UTC

Created attachment 883955 [details]
Fixed ffmpeg ebuild

This is what I ended up doing which works out fine (verified with checking object files with readelf -S)

Comment 2 Michael Cook 2024-02-01 21:37:56 UTC

Created attachment 883956 [details]
Min-repo ebuild demonstrating issue

Comment 3 Michael Cook 2024-02-01 21:39:36 UTC

Created attachment 883957 [details]
Min-repo ebuild eclass-debug.log

Comment 4 Michael Cook 2024-02-02 01:41:08 UTC

I couldn't find any other multilib packages in the tree that has this issue, but media-libs/x264 would if LTO support was added (they support LTO as a config flag) which does make me wonder if pkg_setup would be a better place to do a fix like this.