On Mon, May 25, 2020 at 3:18 PM Michał Górny <mgo...@gentoo.org> wrote: > > On Mon, 2020-05-25 at 19:49 +0200, Alexis Ballier wrote: > > On Mon, 25 May 2020 11:26:26 -0400 > > Mike Gilbert <flop...@gentoo.org> wrote: > > > > > On Mon, May 25, 2020 at 9:13 AM Alexis Ballier <aball...@gentoo.org> > > > wrote: > > > > On Sun, 24 May 2020 20:25:11 +0000 (UTC) > > > > "Thomas Deutschmann" <whi...@gentoo.org> wrote: > > > > > > > > > commit: 6e149596cc76f1bbcee6720828c8c8c92420f2a3 > > > > > Author: Thomas Deutschmann <whissi <AT> gentoo <DOT> org> > > > > > AuthorDate: Sun May 24 19:47:08 2020 +0000 > > > > > Commit: Thomas Deutschmann <whissi <AT> gentoo <DOT> org> > > > > > CommitDate: Sun May 24 20:23:53 2020 +0000 > > > > > URL: > > > > > https://gitweb.gentoo.org/repo/gentoo.git/commit/?id=6e149596 > > > > > > > > > > media-libs/x265: drop USE=pic > > > > > > > > > > Gentoo's toolchain uses PIC by default. Since USE=asm was added, > > > > > we no longer need a USE flag to control that behavior. > > > > > > > > You got it wrong here it seems: USE=pic does not control whether > > > > the toolchain produces PIC or not. Shared libs always are, and have > > > > always been, built that way on Gentoo. > > > > In this case, USE=pic means "no matter what it costs, I do not want > > > > textrels", for the cases of hand written assembly that has to be > > > > rewritten to support PIC. And, still in this case, this costs a lot > > > > of performance, so it is enabled by default on hardened profiles > > > > and not others. > > > > Textrels work fine (on some architectures), they disallow W^X and > > > > force each process using the shared lib to make a "copy" at runtime > > > > in order to resolve relocations, so are not desirable but sometimes > > > > the cost outweights the gain. > > > > > > > > Plus, profiles/features/hardened enables pic by default but knows > > > > nothing about USE=asm so this is a regression for them. > > > > > > The USE flag toggles use of assembly, not use of PIC. The default USE > > > value in the hardened profile should not drive decisions on what we > > > name USE flags. > > > > ... but using a global well documented useflag instead of a local > > invention should drive such decisions. > > What 'global well documented useflag'?
It's neither global, nor well-documented, but several packages do define it locally. profiles % grep ":pic " use.local.desc app-arch/gzip:pic - disable optimized assembly code that is not PIC friendly app-benchmarks/ramspeed:pic - Force shared libraries to be built as PIC (this is slower) dev-libs/gmp:pic - Force static libraries to be built as PIC to avoid TEXTRELs. gnome-base/orbit:pic - Force libname-server-2 to be built as PIC; needed on hardened systems media-libs/x264:pic - disable optimized assembly code that is not PIC friendly media-libs/x265:pic - Disable optimized assembly code that is not PIC friendly media-libs/xvid:pic - disable optimized assembly code that is not PIC friendly media-video/ffmpeg:pic - Force shared libraries to be built as PIC (this is slower) media-video/transcode:pic - disable optimized assembly code that is not PIC friendly www-client/chromium:pic - Disable optimized assembly code that is not PIC friendly I suspect this flag got copy/pasted between various packages related to ffmpeg. That's certainly how chromium ended up with it. Personally, I think it should be renamed to "asm" or something similar in the majority of cases where it actually disables all use of assembly code.
