PowerPC malloc alignment

[Steve Munroe]

Roland McGrath <roland@redhat.com> wrote on 10/31/2007 04:36:48 PM:

> > The main problem is emacs (aka the only user of
> > malloc_set_state/malloc_get_state).  Changing the alignment is really
an ABI
> > change for these interfaces, unless it does some very ugly hacks in it.
>
> That can at least be made easy to detect gracefully via magic/version.
> Is it pathologically difficult to cope with an old dumped state?
> (I'm sure we went into this at the time, but I'm hazy on the details
now.)
> Ideally, it would be doable enough just to handle the existing misaligned
> allocations but always align the new ones.  That copes even if libc
itself
> or some other new-but-compatible library (X, whatever) has newly-compiled
> code that manages to care about the alignment of its own allocations.  It
> is probably sufficient in practice just to have the alignment
parameterized
> by the malloc_save_state so malloc_set_state from an old dumped emacs
> reverts the behavior to the smaller alignment.
>
This thing has been a problem for many moons. Anything we can do to help?

>
Steven J. Munroe
Linux on Power Toolchain Architect
IBM Corporation, Linux Technology Center