Re: Fwd: Re: PATCH: libffi support for s390 architecture

[Andrew Haley <aph at cambridge dot redhat dot com>]

Ulrich Weigand writes:
 > 
 > Andrew Haley wrote:
 > >Ulrich Weigand writes:
 > >> Could you elaborate?  I guess I'll have to implement the
 > >> MD_FALLBACK_FRAME_STATE_FOR macro in the s390 backend.
 > >>
 > >> Apart from this, is there anything else?
 > >
 > >More or less, yes : you'll need MD_FALLBACK_FRAME_STATE_FOR and
 > >possibly a little bit of handler code in java-signal.h.
 > 
 > OK, I think I got it working now.  What I had to change is:
 > 
 >  - Implement MD_FALLBACK_FRAME_STATE_FOR
 >  - Set 'can_unwind_signal=yes' in configure.host
 >  - Implement include/s390-signal.h and set SIGNAL_HANDLER in configure.in
 >  - Do not define HAVE_BACKTRACE as backtrace () can abort on s390 under
 >    some circumstances, especially when called from a signal handler.
 >  - Fix a (non-Java-specific) exception handling bug in the s390 backend
 > 
 > I've already committed the s390 backend parts (exception handling
 > bug fix + MD_FALLBACK_FRAME_STATE_FOR);

Excellent, nice one.

 > Further optimizations of the s390 port could include defining
 > HANDLE_DIVIDE_OVERFLOW and related configure setting on the one
 > hand, and defining enable_hash_synchronization (needs the atomic
 > routines in sysdep/...) on the other hand.  I'm not sure how
 > important this would be; in any case not having those does not
 > appear to impact the correctness of the port.

Indeed it doesn't, but division can be painful with a subroutine call
every time.

 > OK to commit the libjava changes (see above)?

Yes, that's fine.

Andrew.