Re: Linux for Mac available real-soon-now

[Nelson Minar]

>Please fill me in -- what exactly is the problem with AIX systems and
>Objective C?

I'm not able now to find a good reference. If you're seriously
interested in pursuing this, let me know and I can dig through old
mail archives. 

Briefly, though, gcc's implementation of Objective C uses a weird hack
in order to do message dispatch quickly. In particular, it requires
the use of __builtin_apply, a lisp apply equivalent for C that fakes
up a function call dynamically. It's a neat trick, but unfortunately
it's never been ported to PowerPC architectures. Worse yet, last time
I heard the gcc AIX maintainer refused to try to port it, saying that
it was impossible and a bad idea.

The situation is very frustrating. One possible workaround is to use a
set of patches that someone has made that seems to at least hide the
problem, I think by allocating big buffers so data is pushed into a
"safe" spot. These patches are not recommended by the patch authors,
much less the Swarm team. Other solutions take more time and
expertise: either port __builtin_apply to the PowerPC, or modify the
gcc-objc runtime to not require __builtin_apply.

Again, if munging with stack frames is your idea of a good time, drop
me a line and I can give you more technical information.