Fedora and Cross Compiling

[Oliver Falk]

Hi Brendan!

On 06/07/2007 10:41 PM, Brendan Conoboy wrote:
[ ... ]
> Inside Red Hat, my group (GES) creates custom compilers and embedded
> Linux systems for our customers.  We have done this for many years,
> using various upstream sources, building natively and with cross tools.
>  For the last few years, we have used either RHEL or Fedora as our
> upstream source base.

Good self introduction. Now we know, that you know what you're talking
'bout. :-)

[ ... ]

> I would like to see cross compilation become a standard method in
> Fedora.  It scales where native builds don't.  There might be faster arm
> chips these days, but lets not forget all the underpowered embedded CPUs
> and costly systems like s390.  Bootstrapping is simplified.  People
> without access to hardware can work on build problems (Simulators are
> good for this too).

True. But is cross compilation really as reliable as native compilation
is? I'm not experienced with cross compilation... But I think some
errors will only occur on *real native hardware*...

> What are the hurdles to adoption?  Broadly, they break down into
> technical and social:
> 
> Technical:  There must be cross compilers before we can cross compile.
> The build system must be enhanced to support cross compilation. Finally,
> packages must be modified to support cross compilation.

If you would have not written this, I would. :-) Yes, that's the first
part. There where already a few threads about cross compilers for
Fedora; I don't know what the outcome is/was. It seems to be some never
ending story. :-(
<quiet>I saw some cross compilers in CentOS</quiet> :-)

> Social: As a volunteer effort, it is unreasonable to expect existing
> package maintainers to do the work necessary to support cross
> compilation.  There must be people to take on that responsibility and
> work with upstream and package maintainers to integrate the necessary
> changes.

I think that's the same as with secondary arches. Yes, there must be
some team supporting the arch, if it's done via cross compilers or on
native hardware; But with one difference: The people who are involved in
the 2ndary arch stuff, might not be very experienced with cross
compilation; Like me and Alpha for example.

> I don't have fast and easy answers to all of the above,

Nobody would expect... I don't have as well. Just posting my 2 cent...

> but I would like
> to have a discussion about them.  My group may be able to offer
> expertise, patches and some man power toward this goal.  What do you think?

I think for Alpha we will have enough fast machines that can get the job
done. I don't know about the other arches....

If there are volunteers for a arch and you have some man power who can
support the ArchTeam, that would be great - I think. If the arch-team
doesn't want cross compilation..... Let 'em alone. :-)

Best,
 Oliver