[Bug debug/100725] New: dwarf error with --whole-program

[Bug debug/100725] New: dwarf error with --whole-program

[fx at gnu dot org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100725

            Bug ID: 100725
           Summary: dwarf error with --whole-program
           Product: gcc
           Version: 11.1.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: debug
          Assignee: unassigned at gcc dot gnu.org
          Reporter: fx at gnu dot org
  Target Milestone: ---

Extending my example in #100724 with -g, I see a dwarf error, which I assume is
a separate issue:

$ cat test.f90
module tw
  interface
     real function twice (x)
     end function twice
  end interface
end module tw

real function twice (x)
  twice = 2*x
end function twice

use tw
read *, x
print *, twice (x)
end
$ gfortran-11 -O2 -g -fwhole-program test.f90
/usr/bin/ld: /usr/bin/ld: DWARF error: can't find .debug_ranges section.
/tmp/cc8sFtAX.o: in function `MAIN__':
test.f90:(.text+0x7f): undefined reference to `twice_'
collect2: error: ld returned 1 exit status

Changing -g to -gdwarf-4 avoids the error, as does removing -fwhole-program. 
It also works with gcc-10 and -gdwarf-5.  The system is Debian 10 amd64
(binutils 2.31.1, if that matters).

[Bug debug/100725] dwarf error with --whole-program

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100725

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |jakub at gcc dot gnu.org

--- Comment #1 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Those binutils are too old for dwarf5.
When the linker doesn't print any diagnostics, that isn't a big deal, but if it
needs to diagnose something and parse DWARF for that, you need 2.35 or later.

[Bug debug/100725] dwarf error with --whole-program

[fx at gnu dot org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100725

--- Comment #2 from Dave Love <fx at gnu dot org> ---
(In reply to Jakub Jelinek from comment #1)
> Those binutils are too old for dwarf5.
> When the linker doesn't print any diagnostics, that isn't a big deal, but if
> it needs to diagnose something and parse DWARF for that, you need 2.35 or
> later.

Does that mean you can't reasonably use 11 on most distributions without
explicitly using -gdwarf-4?  The release notes suggested to me it would still
work, just not with full functionality somehow, and there is some adjustment
for the binutils version.  Is there some way to configure it to default to
DWARF 4 other than, I guess, adding specs to treat -g as -gdwarf-4?

[Bug debug/100725] dwarf error with --whole-program

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100725

--- Comment #3 from Richard Biener <rguenth at gcc dot gnu.org> ---
(In reply to Dave Love from comment #2)
> (In reply to Jakub Jelinek from comment #1)
> > Those binutils are too old for dwarf5.
> > When the linker doesn't print any diagnostics, that isn't a big deal, but if
> > it needs to diagnose something and parse DWARF for that, you need 2.35 or
> > later.
> 
> Does that mean you can't reasonably use 11 on most distributions without
> explicitly using -gdwarf-4?  The release notes suggested to me it would
> still work, just not with full functionality somehow, and there is some
> adjustment for the binutils version.  Is there some way to configure it to
> default to DWARF 4 other than, I guess, adding specs to treat -g as
> -gdwarf-4?

Yes, on older distributions SUSE patches GCC 11 to default to -gdwarf-4.