[Bug fortran/42104] [F03] runtime segfault with procedure pointer component

["pault at gcc dot gnu dot org" <gcc-bugzilla at gcc dot gnu dot org>]

------- Comment #5 from pault at gcc dot gnu dot org  2009-11-19 13:25 -------
Martien,

Thank you very much for this report.

I have assigned it to myself and have a non-regtested fix:

As remarked by Janus, the problem is with the array argument.  The code
produced for the proc_pointer call is

      parm.13.dtype = 281;
      parm.13.dim[0].lbound = 1;
      parm.13.dim[0].ubound = 2;
      parm.13.dim[0].stride = 1;
      parm.13.data = (void *) &A.12[0];
      parm.13.offset = 0;
      D.1402 = _gfortran_internal_pack (&parm.13);
      D.1404 = funcp.p (&C.1396, D.1402);

The internal_pack should not be there, since the assumed shape formal argument
requires that a descriptor be passed.  This, in its turn comes about because
the symbol funcp is not marked as being always_explicit.

(In fact, he and I had a mid-air collision on this!)

The fix is to make use of the fact a proc_pointer component call is already
detected and can be used to suppress the internal_pack.  Thusly:

Index: gcc/fortran/trans-expr.c
===================================================================
--- gcc/fortran/trans-expr.c    (revision 153651)
+++ gcc/fortran/trans-expr.c    (working copy)
@@ -2918,7 +2918,7 @@
              f = (fsym != NULL)
                  && !(fsym->attr.pointer || fsym->attr.allocatable)
                  && fsym->as->type != AS_ASSUMED_SHAPE;
-             f = f || !sym->attr.always_explicit;
+             f = f || (!sym->attr.always_explicit && !comp);

              if (e->expr_type == EXPR_VARIABLE
                    && is_subref_array (e))

This fixes the PR but has not been regtested.  I will do this tonight.  If all
is well, I will commit as obvious, although your OK would be helpful, Janus!

Paul


-- 

pault at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         AssignedTo|unassigned at gcc dot gnu   |pault at gcc dot gnu dot org
                   |dot org                     |
           Severity|major                       |normal
             Status|NEW                         |ASSIGNED
   Last reconfirmed|2009-11-19 10:45:21         |2009-11-19 13:25:32
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42104