[Patch, Fortran, OOP] PR 78848: [7 Regression] ICE on writing CLASS variable with non-typebound DTIO procedure

[Janus Weil]

Hi all,

the attached patch fixes an ICE on a valid DTIO example, which is in
fact a regression of one of my recent patches. See bugzilla for
details.

Regtests cleanly on x86_64-linux-gnu. Ok for trunk?

Cheers,
Janus


2016-12-18  Janus Weil  <ja...@gcc.gnu.org>

    PR fortran/78848
    * trans-io.c (get_dtio_proc): Generate non-typebound DTIO call for class
    variables, if no typebound DTIO procedure is available.

2016-12-18  Janus Weil  <ja...@gcc.gnu.org>

    PR fortran/78848
    * gfortran.dg/dtio_22.f90: New test.

Index: gcc/fortran/trans-io.c
===================================================================
--- gcc/fortran/trans-io.c      (revision 243776)
+++ gcc/fortran/trans-io.c      (working copy)
@@ -2180,9 +2180,31 @@ get_dtio_proc (gfc_typespec * ts, gfc_code * code,
       formatted = true;
     }
 
-  if (ts->type == BT_DERIVED)
+  if (ts->type == BT_CLASS)
+    derived = ts->u.derived->components->ts.u.derived;
+  else
+    derived = ts->u.derived;
+
+  gfc_symtree *tb_io_st = gfc_find_typebound_dtio_proc (derived,
+                                                 last_dt == WRITE, formatted);
+  if (ts->type == BT_CLASS && tb_io_st)
     {
-      derived = ts->u.derived;
+      // polymorphic DTIO call  (based on the dynamic type)
+      gfc_se se;
+      gfc_expr *expr = gfc_find_and_cut_at_last_class_ref (code->expr1);
+      gfc_add_vptr_component (expr);
+      gfc_add_component_ref (expr,
+                            tb_io_st->n.tb->u.generic->specific_st->name);
+      *dtio_sub = tb_io_st->n.tb->u.generic->specific->u.specific->n.sym;
+      gfc_init_se (&se, NULL);
+      se.want_pointer = 1;
+      gfc_conv_expr (&se, expr);
+      gfc_free_expr (expr);
+      return se.expr;
+    }
+  else
+    {
+      // non-polymorphic DTIO call (based on the declared type)
       *dtio_sub = gfc_find_specific_dtio_proc (derived, last_dt == WRITE,
                                              formatted);
 
@@ -2189,32 +2211,8 @@ get_dtio_proc (gfc_typespec * ts, gfc_code * code,
       if (*dtio_sub)
        return gfc_build_addr_expr (NULL, gfc_get_symbol_decl (*dtio_sub));
     }
-  else if (ts->type == BT_CLASS)
-    {
-      gfc_symtree *tb_io_st;
 
-      derived = ts->u.derived->components->ts.u.derived;
-      tb_io_st = gfc_find_typebound_dtio_proc (derived,
-                                              last_dt == WRITE, formatted);
-      if (tb_io_st)
-       {
-         gfc_se se;
-         gfc_expr *expr = gfc_find_and_cut_at_last_class_ref (code->expr1);
-         gfc_add_vptr_component (expr);
-         gfc_add_component_ref (expr,
-                                tb_io_st->n.tb->u.generic->specific_st->name);
-         *dtio_sub = tb_io_st->n.tb->u.generic->specific->u.specific->n.sym;
-         gfc_init_se (&se, NULL);
-         se.want_pointer = 1;
-         gfc_conv_expr (&se, expr);
-         gfc_free_expr (expr);
-         return se.expr;
-       }
-    }
-
-
   return NULL_TREE;
-
 }
 
 /* Generate the call for a scalar transfer node.  */

! { dg-do run }
!
! PR 78848: [OOP] ICE on writing CLASS variable with non-typebound DTIO procedure
!
! Contributed by Mikael Morin <morin-mik...@orange.fr>

module m
  type :: t
    integer :: i = 123
  end type
  interface write(formatted)
    procedure wf
  end interface
contains
  subroutine wf(this, unit, b, c, iostat, iomsg)
    class(t), intent(in) :: this
    integer, intent(in) :: unit
    character, intent(in) :: b
    integer, intent(in) :: c(:)
    integer, intent(out) :: iostat
    character, intent(inout) :: iomsg
    write (unit, "(i3)", IOSTAT=iostat, IOMSG=iomsg) this%i
  end subroutine
end

program p
  use m
  character(3) :: buffer
  class(t), allocatable :: z
  allocate(z)
  write(buffer,"(DT)") z
  if (buffer /= "123") call abort()
end