[Bug fortran/55854] New: ICE on intent(out) dummy argument with unlimited polymorphic component

[Bug fortran/55854] New: ICE on intent(out) dummy argument with unlimited polymorphic component

[damian at rouson dot net]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55854

             Bug #: 55854
           Summary: ICE on intent(out) dummy argument with unlimited
                    polymorphic component
    Classification: Unclassified
           Product: gcc
           Version: 4.8.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: fortran
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: damian@rouson.net


As demonstrated below, having an "intent(out)" dummy argument with an
unlimited polymorphic component generates an internal compiler error
with a December 23 build of gfortran 4.8:

$ cat ice_on_intent_out_with_unlimted.f90
  type foo
    class(*), allocatable :: x
  end type
contains
  subroutine bar(this)
    type(foo), intent(out) :: this
  end
end
$ gfortran ice_on_intent_out_with_unlimted.f90
ice_on_intent_out_with_unlimted.f90: In function 'bar':
ice_on_intent_out_with_unlimted.f90:5:0: internal compiler error:
Segmentation fault: 11
   subroutine bar(this)
 ^

ice_on_intent_out_with_unlimted.f90:5:0: internal compiler error: Abort trap: 6
gfortran: internal compiler error: Abort trap: 6 (program f951)
Abort trap: 6
$ gfortran --version
GNU Fortran (MacPorts gcc48 4.8-20121223_0) 4.8.0 20121223 (experimental)

[Bug fortran/55854] ICE on intent(out) dummy argument with unlimited polymorphic component

[burnus at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55854

Tobias Burnus <burnus at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |ice-on-invalid-code
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2013-01-03
                 CC|                            |burnus at gcc dot gnu.org,
                   |                            |pault at gcc dot gnu.org
     Ever Confirmed|0                           |1

--- Comment #1 from Tobias Burnus <burnus at gcc dot gnu.org> 2013-01-03 09:40:45 UTC ---
I think it's the same as PR55763 comment 10.

[Bug fortran/55854] ICE on intent(out) dummy argument with unlimited polymorphic component

[burnus at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55854

--- Comment #2 from Tobias Burnus <burnus at gcc dot gnu.org> 2013-01-03 13:03:49 UTC ---
(In reply to comment #1)
> I think it's the same as PR55763 comment 10.

Seemingly not - at least with the patch from PR55763 comment 12, this example
crashes in:

#0  build_function_decl (sym=0x1658420, global=<optimized out>) at
../../gcc/fortran/trans-decl.c:1852
#1  0x0000000000613e37 in gfc_get_symbol_decl (sym=0x1658420) at
../../gcc/fortran/trans-decl.c:1370


The following assert fails for sym == "__copy_CLASS_0_":

1848      /* Allow only one nesting level.  Allow public declarations.  */
1849      gcc_assert (current_function_decl == NULL_TREE
1850                  || DECL_FILE_SCOPE_P (current_function_decl)
1851                  || (TREE_CODE (DECL_CONTEXT (current_function_decl))
1852                      == NAMESPACE_DECL));

Here, "current_function_decl" is "function_decl bar.

[Bug fortran/55854] ICE on intent(out) dummy argument with unlimited polymorphic component

[burnus at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55854

--- Comment #3 from Tobias Burnus <burnus at gcc dot gnu.org> 2013-01-03 14:46:54 UTC ---
The problem seems to be the "gfc_class_null_initializer", where "ts" is
unlimited polymorphic and "init_expr" is of type "__class__$tar_a" (and
EXPR_NULL). The latter leads to the generation of __vtab_CLASS_0_ with the
associated _copy function.

Besides the wrong type, the generation _copy is triggered very late, namely in
gfc_trans_deferred_vars-> gfc_trans_structure_assign. That's the reason for
using the wrong scope and - hence - for the ICE.


Patch:

--- a/gcc/fortran/class.c
+++ b/gcc/fortran/class.c
@@ -414,7 +414,7 @@ gfc_class_null_initializer (gfc_typespec *ts, gfc_expr
*init_expr)
       && ts->u.derived->components->ts.u.derived->attr.unlimited_polymorphic;

   if (is_unlimited_polymorphic && init_expr)
-    vtab = gfc_find_intrinsic_vtab (&(init_expr->ts));
+    vtab = gfc_find_intrinsic_vtab (&ts->u.derived->components->ts);
   else
     vtab = gfc_find_derived_vtab (ts->u.derived);

[Bug fortran/55854] ICE on intent(out) dummy argument with unlimited polymorphic component

[damian at rouson dot net]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55854

--- Comment #4 from Damian Rouson <damian at rouson dot net> 2013-01-03 18:11:56 UTC ---
Apparently an ICE also occurs if the argument intent is removed but "type" is
replaced by "class."  See below.  Is this fixed by the patch in comment 3?

Damian

$ cat ice_on_class_dummy_with_unlimited.f90 
  implicit none
  type foo
    class(*), allocatable :: bar
  end type
contains
  integer function foobar(this)
    class(foo) :: this
  end function
end

$ gfortran ice_on_class_dummy_with_unlimited.f90 
ice_on_class_dummy_with_unlimited.f90: In function 'MAIN__':
ice_on_class_dummy_with_unlimited.f90:8:0: internal compiler error:
Segmentation fault: 11
   end function
 ^

ice_on_class_dummy_with_unlimited.f90:8:0: internal compiler error: Abort trap:
6
gfortran: internal compiler error: Abort trap: 6 (program f951)
Abort trap: 6

$ gfortran --version
GNU Fortran (MacPorts gcc48 4.8-20121223_0) 4.8.0 20121223 (experimental)

[Bug fortran/55854] ICE on intent(out) dummy argument with unlimited polymorphic component

[burnus at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55854

Tobias Burnus <burnus at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |ASSIGNED
         AssignedTo|unassigned at gcc dot       |burnus at gcc dot gnu.org
                   |gnu.org                     |

--- Comment #5 from Tobias Burnus <burnus at gcc dot gnu.org> 2013-01-03 18:55:16 UTC ---
(In reply to comment #4)
> Apparently an ICE also occurs if the argument intent is removed but "type" is
> replaced by "class."  See below.  Is this fixed by the patch in comment 3?

Seems to be fixed by the patch, which has been submitted at
http://gcc.gnu.org/ml/fortran/2013-01/msg00017.html

[Bug fortran/55854] ICE on intent(out) dummy argument with unlimited polymorphic component

[damian at rouson dot net]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55854

--- Comment #6 from Damian Rouson <damian at rouson dot net> 2013-01-03 19:12:09 UTC ---
Awesome -- thanks!  Please let me know once this hits the trunk so I can
request an update of the macports build and try it out.

Damian

(In reply to comment #5)
> (In reply to comment #4)
> > Apparently an ICE also occurs if the argument intent is removed but "type" is
> > replaced by "class."  See below.  Is this fixed by the patch in comment 3?
> 
> Seems to be fixed by the patch, which has been submitted at
> http://gcc.gnu.org/ml/fortran/2013-01/msg00017.html

[Bug fortran/55854] ICE on intent(out) dummy argument with unlimited polymorphic component

[burnus at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55854

--- Comment #7 from Tobias Burnus <burnus at gcc dot gnu.org> 2013-01-04 08:58:03 UTC ---
Author: burnus
Date: Fri Jan  4 08:57:58 2013
New Revision: 194885

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=194885
Log:
2013-01-03  Tobias Burnus  <burnus@net-b.de>

        PR fortran/55854
        PR fortran/55763
        * class.c (gfc_class_null_initializer): Fix finding the vtab.
        (gfc_find_intrinsic_vtab): Use BT_VOID for some components.

2013-01-03  Tobias Burnus  <burnus@net-b.de>

        PR fortran/55854
        PR fortran/55763
        * gfortran.dg/unlimited_polymorphic_3.f03: Remove invalid code.
        * gfortran.dg/unlimited_polymorphic_7.f90: New.
        * gfortran.dg/unlimited_polymorphic_8.f90: New.


Added:
    trunk/gcc/testsuite/gfortran.dg/unlimited_polymorphic_7.f90
    trunk/gcc/testsuite/gfortran.dg/unlimited_polymorphic_8.f90
Modified:
    trunk/gcc/fortran/ChangeLog
    trunk/gcc/fortran/class.c
    trunk/gcc/testsuite/ChangeLog
    trunk/gcc/testsuite/gfortran.dg/unlimited_polymorphic_3.f03

[Bug fortran/55854] ICE on intent(out) dummy argument with unlimited polymorphic component

[burnus at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55854

Tobias Burnus <burnus at gcc dot gnu.org> changed:

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

--- Comment #8 from Tobias Burnus <burnus at gcc dot gnu.org> 2013-01-04 09:00:33 UTC ---
FIXED on 4.8 trunk.

Thanks for the report!