[gentoo-dev] USE=pic reminder

[gentoo-dev] USE=pic reminder

[Mike Frysinger]

as a reminder, NEVER utilize USE=pic in your package unless you know exactly 
what it's for and you're sure you need it ... a quick `grep -Rl ^IUSE=.*pic` 
of the tree shows a bunch of ebuilds which appear to be misusing it:
app-admin/amanda
app-text/djvu
media-libs/guilib
media-libs/libvisual
media-tv/tvtime
media-video/avidemux
net-im/silc-plugin

packages which just straight up suck at life wrt PIC handling:
net-mail/uw-imap
net-mail/checkpassword
(anyone who just has 'append-flags -fPIC' because it 'worked')

fix your packages people or i'll fix you !

to prevent this in the future, perhaps i'll move USE=pic into use.local.desc 
so that people stop thinking it's OK to use normally ... or maybe i'll revise 
the description with 'dont touch this flag unless you know what you are 
doing' ... thoughts ?
-mike
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Re: [gentoo-dev] USE=pic reminder

[Diego 'Flameeyes' Pettenò]

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On Friday 15 April 2005 16:07, Mike Frysinger wrote:
> media-video/avidemux
This is already removed by patch on bug #89097.. I anyway think that this is 
my fault (as for djvu and tvtime, probably).
Sorry about that.

-- 
Diego "Flameeyes" Pettenò
http://wwwstud.dsi.unive.it/~dpetteno/

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Re: [gentoo-dev] USE=pic reminder

[Mike Frysinger]

On Friday 15 April 2005 10:13 am, Diego 'Flameeyes' Pettenò wrote:
> On Friday 15 April 2005 16:07, Mike Frysinger wrote:
> > media-video/avidemux
>
> This is already removed by patch on bug #89097.. I anyway think that this
> is my fault (as for djvu and tvtime, probably).
> Sorry about that.

you have an execuse ... you havent taken the dev quiz yet which has a PIC 
usage question ;)
-mike

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gentoo-dev@gentoo.org mailing list

Re: [gentoo-dev] USE=pic reminder

[Francesco Riosa]

Mike Frysinger wrote:

>as a reminder, NEVER utilize USE=pic in your package unless you know exactly 
>
[... snip of how much PIC is bad ]

A clarification: It's ok to use it _only_ for _libraryes_ by default ?
i.e
econf [...] --with-lib-ccflags="-fPIC"

Using it now and interested to know if it's plain wrong

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Re: [gentoo-dev] USE=pic reminder

[Diego 'Flameeyes' Pettenò]

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On Friday 15 April 2005 16:23, Mike Frysinger wrote:
> you have an execuse ... you havent taken the dev quiz yet which has a PIC
> usage question ;)
Well actually now I taken it :) but the patches where previous to that :P

-- 
Diego "Flameeyes" Pettenò
http://wwwstud.dsi.unive.it/~dpetteno/

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Re: [gentoo-dev] USE=pic reminder

[Jason Stubbs]

On Friday 15 April 2005 23:23, Mike Frysinger wrote:
> On Friday 15 April 2005 10:13 am, Diego 'Flameeyes' Pettenò wrote:
> > On Friday 15 April 2005 16:07, Mike Frysinger wrote:
> > > media-video/avidemux
> >
> > This is already removed by patch on bug #89097.. I anyway think that this
> > is my fault (as for djvu and tvtime, probably).
> > Sorry about that.
>
> you have an execuse ... you havent taken the dev quiz yet which has a PIC
> usage question ;)

How can that be so? Was it removed? Is flameeyes incredible old and silent?

Regards,
Jason Stubbs

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Re: [gentoo-dev] USE=pic reminder

[Simon Stelling]

Hi,

Francesco Riosa wrote:
> A clarification: It's ok to use it _only_ for _libraryes_ by default ?
> i.e
> econf [...] --with-lib-ccflags="-fPIC"
> 
> Using it now and interested to know if it's plain wrong

Shared objects should be built with -fPIC anyway, since a few arches
require it and it makes sense.

Greetings,

blubb
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Re: [gentoo-dev] USE=pic reminder

[Jan Brinkmann]

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On Fri, Apr 15, 2005 at 10:07:53AM -0400, Mike Frysinger wrote:
> as a reminder, NEVER utilize USE=pic in your package unless you know exactly 
> what it's for and you're sure you need it ... a quick `grep -Rl ^IUSE=.*pic` 
> of the tree shows a bunch of ebuilds which appear to be misusing it:
> app-admin/amanda
> app-text/djvu
> media-libs/guilib
> media-libs/libvisual
> media-tv/tvtime
> media-video/avidemux
> net-im/silc-plugin
> 

fixed for:
- media-libs/guilib
- media-libs/libvisual
- media-video/avidemux

-- 
Jan Brinkmann :	Gentoo Developer (Amd64, Java, PPC, Sound, Video)
Email:		luckyduck (at) gentoo.org
Web: 		http://the-luckyduck.de
GPG:		gpg --keyserver pgp.mit.edu --recv-key 0xE38C3BBF

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Re: [gentoo-dev] USE=pic reminder

[Mike Frysinger]

On Friday 15 April 2005 10:29 am, Francesco Riosa wrote:
> Mike Frysinger wrote:
> >as a reminder, NEVER utilize USE=pic in your package unless you know
> > exactly
>
> [... snip of how much PIC is bad ]

PIC isnt bad ... people misusing USE=pic is bad

> A clarification: It's ok to use it _only_ for _libraryes_ by default ?

a good rule of thumb:
shared objects should always be built with PIC

> i.e
> econf [...] --with-lib-ccflags="-fPIC"

ive never seen/used --with-lib-ccflags configure option before, but i imagine 
it'll affect static libraries too right ?  you dont want that

the large majority of autotooled package gets PIC handling right so you 
shouldnt need this kind of crap ...
-mike
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gentoo-dev@gentoo.org mailing list

Re: [gentoo-dev] USE=pic reminder

[Francesco Riosa]

Mike Frysinger wrote:

>On Friday 15 April 2005 10:29 am, Francesco Riosa wrote:
>  
>
>>Mike Frysinger wrote:
>>    
>>
>>>as a reminder, NEVER utilize USE=pic in your package unless you know
>>>exactly
>>>      
>>>
>>[... snip of how much PIC is bad ]
>>    
>>
>
>PIC isnt bad ... people misusing USE=pic is bad
>  
>
received.

>  
>
>>A clarification: It's ok to use it _only_ for _libraryes_ by default ?
>>    
>>
>
>a good rule of thumb:
>shared objects should always be built with PIC
>
>  
>
>>i.e
>>econf [...] --with-lib-ccflags="-fPIC"
>>    
>>
>
>ive never seen/used --with-lib-ccflags configure option before, but i imagine 
>it'll affect static libraries too right ?  you dont want that
>
>the large majority of autotooled package gets PIC handling right so you 
>shouldnt need this kind of crap ...
>-mike
>  
>
fast grepping on "configure" show code for -fPIC utilization --> I must
see how to change the ebuilds my worryes goes to amd64 ... will see

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Re: [gentoo-dev] USE=pic reminder

[Mike Frysinger]

On Friday 15 April 2005 10:35 am, Jason Stubbs wrote:
> On Friday 15 April 2005 23:23, Mike Frysinger wrote:
> > On Friday 15 April 2005 10:13 am, Diego 'Flameeyes' Pettenò wrote:
> > > On Friday 15 April 2005 16:07, Mike Frysinger wrote:
> > > > media-video/avidemux
> > >
> > > This is already removed by patch on bug #89097.. I anyway think that
> > > this is my fault (as for djvu and tvtime, probably).
> > > Sorry about that.
> >
> > you have an execuse ... you havent taken the dev quiz yet which has a PIC
> > usage question ;)
>
> How can that be so? Was it removed? Is flameeyes incredible old and silent?

as he said himself, he made the mistakes before he took the quiz
-mike

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Re: [gentoo-dev] USE=pic reminder

[Kevin F. Quinn]

Mike Frysinger wrote:

> as a reminder, NEVER utilize USE=pic in your package unless you know 
> exactly what it's for and you're sure you need it

I figured this use flag should be used to ensure libraries are built as PIC (i.e. conform to the relevant ABI).  This is a common problem on the media packages for example which often have non-PIC x86 assembler (sometimes these are bugs, other times it's deliberate to get every ounce of performance).  I've been mooting the use of 'use pic' to decide configure options and conditionally apply patches (where the latter would reduce performance).  This was my reading of the description in use.desc.  However it has been indicated to me recently that USE=pic shouldn't be used for this.

If the latter is correct, perhaps the description of the use flag could be improved.

On a related note, USE=pie could be clarified as well (relocated to use.local.desc against sys-lang/gcc perhaps).

As a general comment, I think clear use flag descriptions in *.desc are preferable to rules buried somewhere in the morass of developer documentation.
I searched briefly for policy rules on USE=pic but didn't find any.  "briefly" is the key word here; I'm not about to spend hours reading the aforementioned morass every time I want to know whether I'm using the right USE keyword or not; I expect to find clear answers in use*.desc.

Kev.



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Re: [gentoo-dev] USE=pic reminder

[John Huttley]

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Would someone please expand on this?
perhaps a link if its documented elseware?

I have been compiling everything recently with pic and pie.
I thought this would be a prerequisite for effective use of "prelink".

A minor hit in program speed would not concern me.

Regards,

John

-- 
John Huttley <john@mwk.co.nz <mailto:john@mwk.co.nz>>
MWK Computers Ltd


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Re: [gentoo-dev] USE=pic reminder

[Diego 'Flameeyes' Pettenò]

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On Monday 18 April 2005 22:50, John Huttley wrote:
> I have been compiling everything recently with pic and pie.
> I thought this would be a prerequisite for effective use of "prelink".
It's a prerequisite for prelinking shared libraries, afaik. It's not needed 
for executables, so this shouldn't be a problem.

-- 
Diego "Flameeyes" Pettenò
Gentoo Developer (Gentoo/FreeBSD, Video, Gentoo/AMD64)

http://dev.gentoo.org/~flameeyes/


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Re: [gentoo-dev] USE=pic reminder

[Mike Frysinger]

On Monday 18 April 2005 05:04 pm, Diego 'Flameeyes' Pettenò wrote:
> On Monday 18 April 2005 22:50, John Huttley wrote:
> > I have been compiling everything recently with pic and pie.
> > I thought this would be a prerequisite for effective use of "prelink".
>
> It's a prerequisite for prelinking shared libraries, afaik.

correct

> It's not needed for executables, so this shouldn't be a problem.

executables are not shared objects so you do not build them with PIC (this of 
course does not cover hardened usage of PIC/PIE)
-mike

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Re: [gentoo-dev] USE=pic reminder

[Paul de Vrieze]

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On Tuesday 19 April 2005 00:04, Mike Frysinger wrote:
> On Monday 18 April 2005 05:04 pm, Diego 'Flameeyes' Pettenò wrote:
> > On Monday 18 April 2005 22:50, John Huttley wrote:
> > > I have been compiling everything recently with pic and pie.
> > > I thought this would be a prerequisite for effective use of "prelink".
> >
> > It's a prerequisite for prelinking shared libraries, afaik.
>
> correct

Even on x86 normal (non-prelinked) shared libraries should be built with 
-fPIC. They will however continue to function (albeight slower) when not 
built properly.

Paul

-- 
Paul de Vrieze
Gentoo Developer
Mail: pauldv@gentoo.org
Homepage: http://www.devrieze.net

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