On 9/13/2021 10:52 AM, Koning, Paul wrote:
On Sep 13, 2021, at 3:31 AM, Richard Biener <rguent...@suse.de> wrote:
This makes defaults.h choose DWARF2_DEBUG if PREFERRED_DEBUGGING_TYPE
is not specified by the target and NO_DEBUG if DWARF is not supported.
It also makes us warn when STABS is enabled and removes the corresponding
diagnostic from the Ada frontend. The warnings are pruned from the
testsuite output via prune_gcc_output.
This leaves the following targets without debug support:
pdp11-*-* pdp11 is a.out, dwarf support is difficult
I'll admit that I don't know much about debug formats. It is definitely the
case that pdp11 output is a.out (it may be BSD 2.x style a.out -- which I think
is somewhat different though it's been many years since I looked at that, and
then only briefly). I guess that constrains which debug formats can be used,
but I don't know any details.
My recollection of aout stabs is mostly lost. IIRC we'd emit .stabs
directives to the assembler which would turn into symbol table entries.
Embedded stabs used the same underlying stab strings, but instead put
the information into a special section. That requires an object format
that supports named sections, so it's a non-starter for a.out.
dwarf also requires named sections. While in theory one could probably
do something hackish like dwarf embedded in .stab directives, that just
seems just awful.
pdp11-elf was done as an experiment by someone else, in binutils. I'll ask about the
status of that. If it's possible to deliver that, it would presumably enable DWARF
support. Is that all common code so it's a matter of enabling it, or would "DWARF
machine details for pdp11" have to be defined?
That's going to be the best path forward. Get the pdp11-elf bits
working and the dwarf2 debugging stuff should come along for free.
Jeff
