Re: powerpc64le multilibs and multiarch dir

[Alan Modra <amodra at gmail dot com>]

On Fri, Aug 23, 2013 at 09:41:28PM +0000, Joseph S. Myers wrote:
> On Thu, 22 Aug 2013, Alan Modra wrote:
> 
> > For multiarch, powerpc64le-linux now will use powerpc64le-linux-gnu.
> > Given a typical big-endian native toolchain with os dirs /lib and
> > /lib64, we'll use /lible and /lib64le if supporting little-endian as
> > well.  If you happen to use /lib and /lib32, then the little-endian
> > variants are /lible and /lib32le.  For completeness I also support
> > building big-endian multilibs on a little-endian host.
> 
> Given those directory names, what are the defined dynamic linker paths for 
> 32-bit and 64-bit little-endian (which can't depend on which of the 
> various directory arrangements may be in use)?

We haven't defined the little-endian ld.so variants yet.

> Does the Power Architecture support, in principle, a single system running 
> both big-endian and little-endian processes at the same time

It does.  

>, or is it a 
> matter of hardware configuration or boot-time setup?  Unless both can run 
> at once, it doesn't seem particularly useful to define separate 
> directories for big and little endian since a particular system would be 
> just one or the other.

We (IBM) don't intend to support running both big and little-endian
processes on the same system in the near future.  Perhaps I'm jumping
the gun in defining the multi-os dirs like /lible and /lib64le.  I did
that to make it easier for people ideologically opposed to multiarch
to set up a native powerpc64 compiler that supports both big and
little-endian compilation.  I know the multi-os dirs aren't strictly
needed to do that..  Should I not be defining them yet?

-- 
Alan Modra
Australia Development Lab, IBM