RE: [libunwind] Failed to build from source with gcc 4.0

[James E Wilson]

On Tue, 2005-05-03 at 13:30, Boehm, Hans wrote:
> It looks like the "+S" constraint on *addr is the problem,
> though I won't claim to understand exactly why.

Yes, a gcc bug, I'm fixing it.

By the way, Richard Henderson has recently generalized the gcc support
in this area.  We now have a long list of builtin functions for
synchronization operations.  __sync_fetch_and_OP for add, sub, or, and,
xor, nand.  __sync_OP_and_fetch.  __sync_{bool,var}_compare_and_swap.
__sync_lock_test_and_set.  __sync_lock_release.  __sync_synchronize.
These builtins are already supported by both the x86 and the ia64 ports
on gcc mainline.

When people switch to gcc-4.1 (still a long ways away), atomic_ops.h can
probably just collapse to a few builtin function calls.  You should not
need any asms here anymore.