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Old 05-30-2008, 09:53 PM
Ciaran McCreesh
 
Default RFC: --as-needed to default LDFLAGS (Was: RFC: Should preserve-libs be enabled by default?)

On Sat, 31 May 2008 00:47:44 +0300
Mart Raudsepp <leio@gentoo.org> wrote:
> > Paludis is fine with as-needed. But hey, don't let reality get in
> > the way of your pathetic attempts at turning everything into Paludis
> > bashing.
>
> It happens to be the only package that I know of that couldn't be
> fixed to work with --as-needed (fix for others being to actually
> state linking with a library whose symbols are directly used). I have
> not heard of anything else.

Except that Paludis is fine with --as-needed.

> That doesn't mean Gentoo progress, in maintainability of a running
> system through the ease of ABI breaks meaning magnitudes of less
> recompilations, should be inhibited.

as-needed isn't the right way to do this.

> > And twenty years ago C++ had to work around linkers that only
> > supported eight character symbol names. Reality moves forward,
> > except in situations like these where people try to rice it
> > backwards.
>
> Maybe you'd like to tell that to the authors of the platforms that
> don't support this extreme corner case, but are amongst the platforms
> that we do somewhat support in Gentoo?

Not really. They'll fix it sooner or later. Probably sooner, once C++0x
starts being widely used.

> The story that matters here is, that a C++ corner case that does not
> work on 0.01% of packages with --as-needed and breaks on non-ELF
> platforms, should not cause good things for our users to be shot down.

You could say the same thing for -ffast-math...

--
Ciaran McCreesh
 
Old 05-30-2008, 10:14 PM
Ciaran McCreesh
 
Default RFC: --as-needed to default LDFLAGS (Was: RFC: Should preserve-libs be enabled by default?)

On Fri, 30 May 2008 15:07:43 -0700
Donnie Berkholz <dberkholz@gentoo.org> wrote:
> On 22:53 Fri 30 May , Ciaran McCreesh wrote:
> > On Sat, 31 May 2008 00:47:44 +0300
> > Mart Raudsepp <leio@gentoo.org> wrote:
> > > The story that matters here is, that a C++ corner case that does
> > > not work on 0.01% of packages with --as-needed and breaks on
> > > non-ELF platforms, should not cause good things for our users to
> > > be shot down.
> >
> > You could say the same thing for -ffast-math...
>
> When there's a feature that only breaks one package that we know of,
> wouldn't it make more sense to enable it globally and add an
> exception than to do it the other way around?

Both -ffast-math and --as-needed make the compiler / linker violate
various standards in ways that can't be used safely unless a package
has been explicitly designed to work with it. For packages that have
been explicitly designed to work with either, upstream can add the
options to the build system themselves. For packages that haven't, it's
not Gentoo's place to try to guess whether upstream has designed their
software with ricer flags in mind, and whether if it works by fluke
now it'll still work in the next version.

> I see that a number of packages in the tree explicitly filter
> -ffast-math.

That's mostly from the bad old days when users were encouraged to use
silly CFLAGS...

--
Ciaran McCreesh
 
Old 05-30-2008, 11:08 PM
Luca Barbato
 
Default RFC: --as-needed to default LDFLAGS (Was: RFC: Should preserve-libs be enabled by default?)

Ciaran McCreesh wrote:

On Sat, 31 May 2008 00:47:44 +0300
Mart Raudsepp <leio@gentoo.org> wrote:

Paludis is fine with as-needed. But hey, don't let reality get in
the way of your pathetic attempts at turning everything into Paludis
bashing.

It happens to be the only package that I know of that couldn't be
fixed to work with --as-needed (fix for others being to actually
state linking with a library whose symbols are directly used). I have
not heard of anything else.


Except that Paludis is fine with --as-needed.



Ok, then everything in the tree is covered and we can move to having
--as-needed as default.


lu

--

Luca Barbato
Gentoo Council Member
Gentoo/linux Gentoo/PPC
http://dev.gentoo.org/~lu_zero

--
gentoo-dev@lists.gentoo.org mailing list
 
Old 05-30-2008, 11:13 PM
Luca Barbato
 
Default RFC: --as-needed to default LDFLAGS (Was: RFC: Should preserve-libs be enabled by default?)

Ciaran McCreesh wrote:

On Fri, 30 May 2008 15:07:43 -0700
Donnie Berkholz <dberkholz@gentoo.org> wrote:

On 22:53 Fri 30 May , Ciaran McCreesh wrote:

On Sat, 31 May 2008 00:47:44 +0300
Mart Raudsepp <leio@gentoo.org> wrote:

The story that matters here is, that a C++ corner case that does
not work on 0.01% of packages with --as-needed and breaks on
non-ELF platforms, should not cause good things for our users to
be shot down.

You could say the same thing for -ffast-math...
When there's a feature that only breaks one package that we know of,
wouldn't it make more sense to enable it globally and add an

exception than to do it the other way around?


Both -ffast-math and --as-needed make the compiler / linker violate
various standards in ways that can't be used safely unless a package
has been explicitly designed to work with it.


I know exactly which standard -ffast-math violates (IEEE/ISO floating
point spec) and how (the man page is quite complete about this),
--as-needed doesn't have any warning about this, there isn't any
standard that it violates since it's the default behavior at least for 2
platform (one from those who wrote most of the ELF spec...).

Point the spec, and the paragraph violated.

lu

--

Luca Barbato
Gentoo Council Member
Gentoo/linux Gentoo/PPC
http://dev.gentoo.org/~lu_zero

--
gentoo-dev@lists.gentoo.org mailing list
 
Old 05-30-2008, 11:16 PM
Ciaran McCreesh
 
Default RFC: --as-needed to default LDFLAGS (Was: RFC: Should preserve-libs be enabled by default?)

On Sat, 31 May 2008 01:08:21 +0200
Luca Barbato <lu_zero@gentoo.org> wrote:
> > Except that Paludis is fine with --as-needed.
>
> Ok, then everything in the tree is covered and we can move to having
> --as-needed as default.

Is the next version of everything in the tree covered? Have you made
sure that software isn't merely working by fluke? Is Gentoo really that
desperate to turn everyone into a ricer?

I'd bet you could get a pretty long way by shoving -ffast-math into
CFLAGS by default before anyone would notice...

--
Ciaran McCreesh
 
Old 05-30-2008, 11:18 PM
Luca Barbato
 
Default RFC: --as-needed to default LDFLAGS (Was: RFC: Should preserve-libs be enabled by default?)

Ciaran McCreesh wrote:

I'd bet you could get a pretty long way by shoving -ffast-math into
CFLAGS by default before anyone would notice...



Non sequitur. We are talking about --as-needed, not -ffast-math.

--

Luca Barbato
Gentoo Council Member
Gentoo/linux Gentoo/PPC
http://dev.gentoo.org/~lu_zero

--
gentoo-dev@lists.gentoo.org mailing list
 
Old 05-30-2008, 11:26 PM
Ciaran McCreesh
 
Default RFC: --as-needed to default LDFLAGS (Was: RFC: Should preserve-libs be enabled by default?)

On Sat, 31 May 2008 01:13:58 +0200
Luca Barbato <lu_zero@gentoo.org> wrote:
> I know exactly which standard -ffast-math violates (IEEE/ISO floating
> point spec) and how (the man page is quite complete about this),
> --as-needed doesn't have any warning about this, there isn't any
> standard that it violates since it's the default behavior at least
> for 2 platform (one from those who wrote most of the ELF spec...).
> Point the spec, and the paragraph violated.

ISO/IEC 14882:1998 section 3.7.1 paragraph 2.

--
Ciaran McCreesh
 

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