Help with GCC (port-vax/44155)

["Valeriy E. Ushakov" <uwe%stderr.spb.ru@localhost>]

GCC has some code for DWARF2 stack unwinding on VAX but it's neither
correct, nor complete, so C++ exceptions currently don't work on VAX
at all.

I did some initial investigation, but my gcc fu is not enough to fix
it completely.  Details in port-vax/44155, but the summary is:

. fix FRAME_POINTER_CFA_OFFSET

. provide "eh_return" instruction pattern
  (the asm code to be emited is in the PR)

. what are compatibility implications of introducing
  DWARF2 column for saved PSW?


If we can fix exceptions, than I guess someone can setup ATF runs
with Anita (http://www.gson.org/netbsd/anita/) but using SIMH instead
of QEMU (as we already do for i386, amd64 and sparc).

-uwe