[OE-core] multilib theory & practice

[Richard Purdie]

On Sun, 2011-08-07 at 11:50 -0500, Kumar Gala wrote:
> On Aug 6, 2011, at 3:56 PM, Kumar Gala wrote:
> 
> > I'm looking at trying to get multilib working for powerpc.  However I'm a bit lost in how this is suppose to work from a few different perspectives:
> > 
> > 1. from user perspective (I'm starting with a 64-bit build in /lib64 and adding 32-bit that would be in /lib):
> > 
> > (i've added in local/conf):
> > require conf/multilib.conf
> > MULTILIBS = "multilib:lib"
> > DEFAULTTUNE_virtclass-multilib-lib = "powerpc"
> > 
> > What should this end up producing?  Do I get a 32-bit set of libs built automatically?  What else do I need to do?
> > 
> > 2. From a infrastructure point of view:
> > 
> > * Do have a single compiler that is multi-arch or 2 compilers? (not sure how the x86_64 toolchain works today)
> > * what areas should I investigate that might need tweaking that are arch specific?
> > * should I see different task names for the new multilib builds? (or the 32-bit specific builds?)
> 
> To add to this I'm wondering how we get proper eglibc for 32-bit, how we get proper gcc libs (libgcc, etc).

As per my reply, we currently treat this as two separate toolchains so
this makes this part of the problem very easy.

Cheers,

Richard