Re: [gentoo-dev] Review: news item and script for CPU_FLAGS_X86

[Alexis Ballier]

On Mon, 26 Jan 2015 20:09:18 +0100
Michał Górny <mgorny@g.o> wrote:

> Dnia 2015-01-26, o godz. 16:40:35
> Alexis Ballier <aballier@g.o> napisał(a):
>
> > On Mon, 26 Jan 2015 16:20:10 +0100
> > Michał Górny <mgorny@g.o> wrote:
> >
> > > Dnia 2015-01-26, o godz. 12:41:00
> > > Alexis Ballier <aballier@g.o> napisał(a):
> > >
> > > > On Sat, 24 Jan 2015 00:35:39 +0100
> > > > Michał Górny <mgorny@g.o> wrote:
> > > >
> > > > > Title: CPU_FLAGS_X86 introduction
> > > > > Author: Michał Górny <mgorny@g.o>
> > > > > Content-Type: text/plain
> > > > > Posted: 2015-01-xx
> > > > > Revision: 1
> > > > > News-Item-Format: 1.0
> > > > > Display-If-Keyword: amd64 ~amd64 x86 ~x86
> > > >
> > > > but.... why ?
> > > > will you write another news item for other arches ?
> > >
> > > Are there other arches using CPU_FLAGS_X86? ;) But seriously, the
> > > item is quite arch-specific. Other arches are likely to have
> > > kinda specific flags with rules for choosing them, another script
> > > etc.
> >
> > I think it is better to have it done all in one pass: even if there
> > is no script, it is just as good as it is today.
> >
> > My concern is: This will clutter e.g. ffmpeg ebuild by having two
> > ways to pass cpu flags, depending on the arch, and will give a kind
> > of silly output with "altivec" or "neon" as standard useflags but
> > x86 cpu flags as USE_EXPAND. This is too much inconsistent to me.
>
> I understand your concern but unless someone's going to do the work
> for other arches, I doubt there's a point in waiting forever. Script
> is a minor issue, but someone has to figure out how various packages
> behave and what flags to use.
>

It doesn't have to be perfect, just consistent. As of figuring out how
to have such flags, I already gave you the link: profiles/base/use.mask.

Let's see:

# ppc arch specific USE flags
altivec
pbbuttonsd
ppcsha1

# mips arch specific USE flags
n32
n64
fixed-point
loongson2f
mips32r2
mipsdspr1
mipsdspr2
mipsfpu

# sparc arch specific USE flags
vis
ultra1

etc.

grep their desc in use.desc or .local.desc and paste these to
profiles/desc/cpu_flags_xxx.desc, and you're done.
if you want to do things better, open a bug for relevant arch team to
review it, improve it or remove useless stuff; it'd be better tracked
than a discussion here.



Anyway, flags renamings will have to be done on a per-package basis,
probably with a bug openened and certainly with proper review done, so
that being x86* only or all arches makes little to no difference. Even
better: you won't have me on your back ranting against pointless
inconsistencies :)

Alexis.