update dwarf2 asm unwind info [hppa64-*-* failures]

[John David Anglin]

> 
> John David Anglin wrote:
> > Making .eh_frame read-only would
> > have to be forced.  I believe that we would need the same pc-relative
> > indirect trick as we currently use on linux to get the plabel out of
> > .eh_frame (see patch below).
> 
> The patch is wrong.  We handle the indirect part inside the compiler
> before we pass it on to the assembler.

Ok, I see.  It handles the case in a manner similar to that in
dwarf2asm.c.  I will recheck but I believe there was a problem in
using dw2_force_const_mem() for the indirection to a plabel.  We
handle the output ourself using ASM_MAYBE_OUTPUT_ENCODED_ADDR_RTX
when not using CFI directives.

Trying to make .eh_frame read-only didn't work on hppa64-hpux.

So, we have to deal with the assembler using pc-relative relocations
for the FDE's until I see if segment relative relocations can
be made to work.  Possibly, DIFF_EXPR_OK shouldn't be defined although
I'm hesitant to give up completely on it as it works within a
segment.  However, it still should be possible to generate pc-relative
data using the obscure $PIC_pcrel$0 semantics.

Dave
-- 
J. David Anglin                                  dave.anglin@nrc-cnrc.gc.ca
National Research Council of Canada              (613) 990-0752 (FAX: 952-6602)