Re: Debugging multi-threaded SSE using programs

[Mark Kettenis <kettenis@wins.uva.nl>]

   From: Ulrich Drepper <drepper@redhat.com>
   Date: 01 Sep 2001 14:34:47 -0700

   Mark Kettenis <kettenis@wins.uva.nl> writes:

   > Would it be OK to provide an implementation of these calls for Linux
   > x86 that manages the SSE registers?

   Yes.  But please try to make it a bit generic so that it can be used
   with the different registers extensions already out there and also has
   room if there are yet more extensions to come.

I did some reverse-engineering on sparc-sun-solaris2.6, and it seems
that we can punt any interpretation of these extra registers to the
debugger.  In libthread_db we should simply call ps_lgetxregsize,
ps_lgetxregs or ps_lsetxregs with the appropriate arguments, or return
an appropraite error code.  This means that we cannot zero out the
register set when a thread already terminated as we do for
td_thr_getfpregs.  So be it.  Any debugger will need to deal with it.

Since the current libthread_db doesn't require ps_lgetxregsize,
ps_lgetxregs and ps_lsetxregs, I probably should use weak references
for these functions, shouldn't I?

Mark