[Bug fortran/56659] Segfault due to missing libcpp error handler for "gfortran -cpp"

["kapinos at itc dot rwth-aachen.de" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=56659

--- Comment #7 from kapinos at itc dot rwth-aachen.de ---
Sorry, for not adding the reproducer again. It is very K.I.S.S.:

- make (or reuse) an dir w/o read permissions
- use it as include dir at *any* Fortran source including empty ones.

The output of gfortran 10.2.0 was added previously, cf.
 > f951: Warning: Include directory ‘./foo/bar’: Permission denied
 > f951: internal compiler error: in cpp_diagnostic_at, at libcpp/errors.c:41
.......




$ cat runme007.sh
mkdir -p foo/bar
chmod 000 foo
echo
"-------------------------------------------------------------------------"
gfortran -c  -I./foo/bar mini.F90
echo "------------------------------------------------------------------------"
gfortran -v

$ cat mini.F90
program mini
end







On 10/6/21 11:23 PM, burnus at gcc dot gnu.org wrote:
> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=56659
> 
> --- Comment #6 from Tobias Burnus <burnus at gcc dot gnu.org> ---
> (In reply to Paul from comment #5)
>> Just tried all versions of gfortran available up to 10.2.0: the very same
>> 'internal compiler error' is still reported using the initial reproducer.
> 
> Can you share the initial reproducer? The email link to gmane no longer works
> and what is written in the the original description and in the other email
> lacks the details. It only has:
> 
> Test case:
> * mkdir -p foo/bar
> * chmod 000 foo
> * gfortran -cpp some_file.F90
> 
> But that obviously does not use 'foo/bar' at all.
> 
> I have no idea what's in 'some_file.F90'; the most straight-forward input would
> be:
>    echo '#include "foo/bar/file.f90"' > some_file.F90
> but when I try this, GCC 7, 8, 9, 10 of Ubuntu and the current development
> version all show the same:
>    some_file.F90:2:2:
>    Fatal Error: foo/bar/file.f90: Permission denied
> 
> (The off-by-one line number issue is PR 100904.)
> 
> I assume that your file contains something different - but what? Can you
> enlighten me?
> 
>   * * *
> 
> A couple of fixes were done in the development branch (to be released as GCC 12
> around April), cf. PR 55534.
>