[09:05] [telegram] @mitya57 if qt6-base need lto disabling, would you say the rest of the stack does as well? [09:06] [telegram] Or do we need to work through the stack one by one? [09:38] [telegram] I don't know. In Qt 5 times build flags from qtbase applied everywhere, but Qt 6 has a different build system so this may have changed. [09:43] [telegram] Trying qt base anyway, then will see what happens I guess. I note most of qt5 seems to be in the lto-disabled-list package [09:45] [telegram] Ah, that will explain it. [09:45] [telegram] Adding to that list would be much better than patching everything. [09:46] [telegram] Indeed [10:57] [telegram] qt6-base build with LTO off, but then fails on ppc64el on symbols [10:57] [telegram] sigh.... [10:58] [telegram] I can mark those symbols as optional in Debian. [11:00] [telegram] That would be good. I'll retry builds in a clean PPA 1st, as armhf in the current one actually built with LTO, so I want to start there from scratch (re @mitya57: I can mark those symbols as optional in Debian.) [11:00] [telegram] Then I guess I can follow this: https://www.processon.com/view/link/61f50f161efad479c0785a08 [11:02] [telegram] @mitya57 tempting to just shove all of Qt is the lto-disable-list and be done with it, but I guess it should all be checked propperly? [11:04] [telegram] If Qt 5 was there, then it makes sense. [11:07] [telegram] Ok, I will compromise then. Build qt6-base, then try the next tier in the Qt6 stack. If most of that also fails with LTO, then I'll stop and propose the whole stack goes into the lto-disabled-list. Reasonable? (re @mitya57: If Qt 5 was there, then it makes sense.) [11:08] [telegram] https://matterbridge.lubuntu.me/e0896d46/file_3938_tgs.webp [11:08] [telegram] Nice sticker! [15:54] [telegram] so far only qt6-qtbase seems to have an LTO issue [15:54] [telegram] symbols are an issue though [15:58] [telegram] wondering if some of those are LTO related [16:01] How do you enable LTO? If you just pass -flto, that won't work [16:02] You'd need to use DCMAKE_INTERPROCEDURAL_OPTIMIZATION:BOOL=ON and let Qt/CMake handle it itself [16:02] Then it disables LTO on the version tagging object. [16:06] fvogt: LTO is turned on via a patched dpkg in Ubuntu [16:06] I suspected something like that [16:07] https://launchpad.net/ubuntu/+source/dpkg/1.20.7.1ubuntu2 [16:08] https://launchpad.net/ubuntu/+source/dpkg/1.20.7.1ubuntu4 [16:08] You'll have to opt out of that and go the cmake way [16:09] if I end up adding the qt6 packages to the excluded list it will never get enabled [16:38] [telegram] yes, disabling LTO seems to make most symbols issues go away. probably some slight delta to go to debian for ppc64el symbols [16:40] You don't have to disable LTO, just disable the dpkg injection of -flto and set CMAKE_INTERPROCEDURAL_OPTIMIZATION instead [16:41] not going to carry such a delta to debian. adding all qt6 to the lto-disabled list until debian enabled LTO by default seems the best thing here [17:17] [telegram] https://launchpad.net/bugs/1961324