Putting cross compilers into Fedora

[Andrew Haley]

On 09/01/2010 01:06 PM, Ralf Corsepius wrote:
>  On 09/01/2010 01:53 PM, Andrew Haley wrote:
>> On 09/01/2010 12:48 PM, Ralf Corsepius wrote:
>>> On 09/01/2010 12:41 PM, David Howells wrote:
>>>> Would it be worth our while putting into Fedora basic gcc and
>>>> binutils rpms
>>>> for cross compilers for all the Linux arches?  I keep finding the
>>>> need to
>>>> compile kernels for arches other than the x86_64 boxes I normally
>>>> use, and I
>>>> keep borrowing prebuilt compilers off others (usually Al Viro -
>>>> thanks Al!) to
>>>> do this.
>>>>
>>>> However, as the kernel advances, older compilers cease being able to
>>>> compile
>>>> it, so I have to go finding new compilers again.
>>>>
>>>> It would be much easier if I could just yum install them.
>>>>
>>>> Any thoughts on whether it would be worthwhile?
>>> I'd welcome it.
>>>
>>> However it would be a very challenging task on all levels:
>>> - Fedora's rpm and some components the build-infrastructure have serious
>>> issues related to cross-building.
>>>
>>> - A cross compiler alone is not worth it, you need a whole zoo of
>>> further cross-target packages to make it usable.
>> I don't see why.
> You'd need at minimum the infrastructure gcc itself needs, e.g. glibc,
> kernel-headers, mpfr, mpc, libelf, ppl, cloog etc.

They're already there for host gcc.

> Which packages you exactly need, depends upon which packages you want to
> package (e.g. cross-gdb's have another exciting zoo of package
> dependencies).
> 
>>    If you assume that someone compiling for user space
>> has a vague idea what they are doing, they will know how to install the
>> -devel packages for their target system somewhere the compiler can find
>> them.
> That's another aspect I am referring to.
> 
> Basically there would be 2 approaches this
> a) provide cross-devel packages for each and every library of a certain
> amount of interest in Fedora.

No need for that.

> This is what the mingw32 cross toolchain in Fedora does. This approach
> is applicable when you have "few packages", but it'll rather soon
> explode when adding more targets.
> 
> b) To equippe the rpm/yum/mock etc. infrastructure with a mechanism to
> pull-in "foreign binaries" into a sys-root (E.g. to install Fedora
> *.ppc.rpm rpms into /usr/ppc-redhat/sys-root). So far, such mechanism
> doesn't exist.

No need for that eithr.  They can figure out

rpm2cpio package | cpio -i -

Andrew.