Dealing with two-abi architectures

Several of the LSB architectures require
dual-ABI support.

As of right now, I haven't read two of
the three processor supplements referenced
(hey, there's only so much time...)

Itanium systems are delivered with LP64 Itanium
binaries, and have a requirement to run IA32
binaries.  This requirement is a "common usage"
requirement and is not enshrined in the LSB. 
Thus this isn't a real dual-ABI system from the
LSB viewpoint.

AMD64 systems are delivered as LP64 AMD64
binaries, and must also run IA32 binaries.

PPC64 systems are delivered as ILP32 PPC32
native binaries, and must also run LP64 PPC64
binaries.


The lsbsi question is: how should these
requirements be accommodated, and what changes
to the lsbsi build procedure need to be made
to implement that.

In past discussions, the feeling has been that
the lsbsi should be built consistent with
what the Linux distributions are doing, and
a separate build phase would build the libraries
that support the "other ABI".  That is, the
AMD64 lsbsi should be a 64-bit build using
the current lsbsi model, and then an extra phase
is done to produce ILP32 libraries. And the
PPC64 build should be essentially the PPC32
build (we think we could use the PPC32 lsbsi,
but maybe prefer to build it in a PPC64 environment -
open for discussion) and the extra phase builds
the LP64 libraries.  I propose to ignore the
Itanium issue at this time.

If this seems like the correct approach, I'll
start looking into how to structure this within
the lsbsi build process (perhaps after looking
at the issues raised by uplifting the build
tool to the current version, which has been on
my todo list for a while but waiting for a moment
when there isn't a great deal of time pressure).
It's still expected that the "architecture 
champions" for PPC64 and AMD64 will actually
take the process through to release.

If it's not the right approach, now would be
a good time to bring up why not, before time
gets invested into going down the wrong path.

Cheers,

Mats