FW: Java vs. Dwarf2 EH Unwinder

[David Mosberger]

Sorry if I jump into the middle of this discussion.  Hans was kind enough
to forward the mail.

  Rich> On Thu, Mar 28, 2002 at 09:31:26AM +0000, Andrew Haley wrote:

  Andrew> Surely you'd need to pass the entire processor state to the
  Andrew> _Unwind_RaiseException() variant.

  Rich> Indeed.  I would be willing to create a variant that took a
  Rich> sigcontext* or something.

  Andrew> This would only work if the kernel saved the entire processor
  Andrew> state in the sigcontext and then called the signal handler.  This
  Andrew> does happen on some architectures, but not all, and therefore
  Andrew> it's not a totally general solution.

  Rich> There has to be enough information for the kernel to restore
  Rich> enough state.  What do you have in mind as an example of
  Rich> not-enough-state being saved?

For example, ia64 linux only saves the scratch registers on signal
delivery.  Thus, some preserved registers may live on the signal stack
and you can't just short-circuit out of the signal handler.

	--david