[Bug fortran/100860] New: class(*) type is (character(*)) produces a segmentation fault when run

[Bug fortran/100860] New: class(*) type is (character(*)) produces a segmentation fault when run

[thomas.robinson at noaa dot gov]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100860

            Bug ID: 100860
           Summary: class(*) type is (character(*)) produces a
                    segmentation fault when run
           Product: gcc
           Version: 11.1.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: fortran
          Assignee: unassigned at gcc dot gnu.org
          Reporter: thomas.robinson at noaa dot gov
  Target Milestone: ---

When a string is passed as an argument to a subroutine where the argument is
`class(*)`, there is a seg fault when the type is selected.  Other types seem
to be working.
Previous versions of gfortran have no problem compiling and running this simple
program.  I think the code is correct.  It seems to be gcc 11 that has an
issue.

Here is some test code:

module ctest
contains

subroutine sub (carg, slen)

 class(*), intent (in) :: carg
 integer, optional, intent (in)  :: slen

 select type (carg)
 type is (character(*))
   if (.not.present(slen)) then
     write (6,*) "This is an error dealing with a string"
   else
     write (6,*) "string length is ",slen
     write (6,*) "String is ",carg(1:slen)
   endif

 type is (integer)
   write (6,*) "Integer type is ", carg
 type is (real)
   write (6,*) "Real type is ", carg
 class default
   write (6,*) "Not the right type"
 end select


end subroutine sub


end module ctest

program test

use ctest

character (len=10) :: c10
character (len=:), allocatable :: sall
integer :: i=100
real :: r = 999.9
logical :: l = .true.
 call sub (r)
 call sub (i)
 call sub (l)
 c10="12345"
 allocate(character (len=i) :: sall)
 sall = "87654321"
! write (6,*) "c10=",trim(c10),"::LEN=",len_trim(c10)
! call sub(trim(c10), len_trim(c10))
 write (6,*) "sall=",trim(sall),"::LEN=",len_trim(sall)
 call sub(trim(sall),len_trim(sall))



end program test

Here is the output
 Real type is    999.900024    
 Integer type is          100
 Not the right type
 sall=87654321::LEN=           8

Program received signal SIGSEGV: Segmentation fault - invalid memory reference.


I tried with heap and stack strings, and both fail (you can see I have the
first one commented out).  Please let me know if there's any more information
you need.

[Bug fortran/100860] class(*) type is (character(*)) produces a segmentation fault when run

[anlauf at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100860

anlauf at gcc dot gnu.org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Last reconfirmed|                            |2021-06-01
             Status|UNCONFIRMED                 |WAITING
     Ever confirmed|0                           |1

--- Comment #1 from anlauf at gcc dot gnu.org ---
Possibly related to pr100551, which was fixed after the 11.1 release.
I do not see the issue  with the current mainline or 11-branch version.
Can you please check?

[Bug fortran/100860] class(*) type is (character(*)) produces a segmentation fault when run

[dominiq at lps dot ens.fr]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100860

--- Comment #2 from Dominique d'Humieres <dominiq at lps dot ens.fr> ---
WORKSFORME from GCC7 up to trunk.

[Bug fortran/100860] class(*) type is (character(*)) produces a segmentation fault when run

[thomas.robinson at noaa dot gov]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100860

--- Comment #3 from Tom Robinson <thomas.robinson at noaa dot gov> ---
I tried with the main (12.0.0) and this code ran.  I will try it in with our
main codebase to confirm it works there too.

[Bug fortran/100860] class(*) type is (character(*)) produces a segmentation fault when run

[thomas.robinson at noaa dot gov]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100860

Tom Robinson <thomas.robinson at noaa dot gov> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|WAITING                     |RESOLVED
         Resolution|---                         |FIXED

--- Comment #4 from Tom Robinson <thomas.robinson at noaa dot gov> ---
Actually, it looks like someone else saw this bug report and tested the code. 
They reported it worked.  Thanks.