[Bug fortran/55960] New: [OOP] ICE in replace_comp, at fortran/expr.c:4356

[Bug fortran/55960] New: [OOP] ICE in replace_comp, at fortran/expr.c:4356

[janus at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55960

             Bug #: 55960
           Summary: [OOP] ICE in replace_comp, at fortran/expr.c:4356
    Classification: Unclassified
           Product: gcc
           Version: 4.8.0
            Status: UNCONFIRMED
          Keywords: ice-on-valid-code
          Severity: normal
          Priority: P3
         Component: fortran
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: janus@gcc.gnu.org


Reported at http://gcc.gnu.org/ml/fortran/2013-01/msg00109.html.

Reduced test case:

module pdfs
  type, abstract :: pdf
  contains
    procedure(getdims), deferred :: getdims
    procedure(getx), deferred :: getx
  end type pdf

  abstract interface
    pure function getdims(this)
      import pdf
      class(pdf), intent(in) :: this
      integer getdims
    end function getdims

    pure function getx(this)
      import pdf
      class(pdf), intent(in) :: this
      real, dimension(getdims(this)) :: getx
    end function getx
  end interface

end module pdfs


Yields the ICE:

f951: internal compiler error: in replace_comp, at fortran/expr.c:4356
0x57af34 replace_comp
        /home/jweil/gcc48/trunk/gcc/fortran/expr.c:4356
0x57a3a5 gfc_traverse_expr(gfc_expr*, gfc_symbol*, bool (*)(gfc_expr*,
gfc_symbol*, int*), int)
        /home/jweil/gcc48/trunk/gcc/fortran/expr.c:4073
0x57afa5 gfc_expr_replace_comp(gfc_expr*, gfc_component*)
        /home/jweil/gcc48/trunk/gcc/fortran/expr.c:4366
0x5f0c77 resolve_fl_derived0
        /home/jweil/gcc48/trunk/gcc/fortran/resolve.c:12622
0x5f1d9e resolve_fl_derived
        /home/jweil/gcc48/trunk/gcc/fortran/resolve.c:12961
0x5f296a resolve_symbol
        /home/jweil/gcc48/trunk/gcc/fortran/resolve.c:13229
0x611e1a do_traverse_symtree
        /home/jweil/gcc48/trunk/gcc/fortran/symbol.c:3449
0x611ee6 gfc_traverse_ns(gfc_namespace*, void (*)(gfc_symbol*))
        /home/jweil/gcc48/trunk/gcc/fortran/symbol.c:3474
0x5f68db resolve_types
        /home/jweil/gcc48/trunk/gcc/fortran/resolve.c:14889
0x5f6d28 gfc_resolve(gfc_namespace*)
        /home/jweil/gcc48/trunk/gcc/fortran/resolve.c:14989
0x5ce730 gfc_parse_file()
        /home/jweil/gcc48/trunk/gcc/fortran/parse.c:4603
0x61b4c1 gfc_be_parse_file
        /home/jweil/gcc48/trunk/gcc/fortran/f95-lang.c:189

[Bug fortran/55960] [OOP] ICE in replace_comp, at fortran/expr.c:4356

[janus at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55960

--- Comment #1 from janus at gcc dot gnu.org 2013-01-13 10:32:08 UTC ---
With this variant:

module pdfs
  type :: pdf
  end type pdf

  abstract interface
    pure function getdims(this)
      import pdf
      class(pdf), intent(in) :: this
      integer getdims
    end function getdims
  end interface

contains

  pure function getx(this)
    class(pdf), intent(in) :: this
    real, dimension(getdims(this)) :: getx
  end function getx

end module pdfs


I get the correct error message (unfortunately twice):

    real, dimension(getdims(this)) :: getx
                    1
Error: ABSTRACT INTERFACE 'getdims' must not be referenced at (1)


I'm not completely sure if the usage of 'getdims' is valid in comment 0.

[Bug fortran/55960] [OOP] ICE in replace_comp, at fortran/expr.c:4356

[janus at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55960

--- Comment #2 from janus at gcc dot gnu.org 2013-01-13 10:36:22 UTC ---
Yet another variant:


module pdfs
  type, abstract :: pdf
  contains
    procedure(getdims), deferred :: getdims
    procedure(getx), deferred :: getx
  end type pdf

  abstract interface
    pure function getdims(this)
      import pdf
      class(pdf), intent(in) :: this
      integer getdims
    end function getdims

    pure function getx(this)
      import pdf
      class(pdf), intent(in) :: this
      real, dimension(this%getdims()) :: getx
    end function getx
  end interface

end module pdfs



gives me (four times!):

      real, dimension(this%getdims()) :: getx
                      1
Error: Function 'this' at (1) must be PURE


which is of course bogus, since 'this' is not even a function, and getdims is
actually pure.

[Bug fortran/55960] [OOP] ICE in replace_comp, at fortran/expr.c:4356

[janus at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55960

--- Comment #3 from janus at gcc dot gnu.org 2013-01-13 16:57:18 UTC ---
This fixes the ICE in comment 0:

Index: gcc/fortran/expr.c
===================================================================
--- gcc/fortran/expr.c    (revision 195125)
+++ gcc/fortran/expr.c    (working copy)
@@ -4335,9 +4335,11 @@ replace_comp (gfc_expr *expr, gfc_symbol *sym, int
      the symtree rather than create a new one (and probably fail later).  */
       stree = gfc_find_symtree (ns ? ns->sym_root : gfc_current_ns->sym_root,
                       expr->symtree->n.sym->name);
-      gcc_assert (stree);
-      stree->n.sym->attr = expr->symtree->n.sym->attr;
-      expr->symtree = stree;
+      if (stree)
+    {
+      stree->n.sym->attr = expr->symtree->n.sym->attr;
+      expr->symtree = stree;
+    }
     }
   return false;
 }

[Bug fortran/55960] [OOP] ICE in replace_comp, at fortran/expr.c:4356

[janus at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55960

janus at gcc dot gnu.org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2013-01-19
     Ever Confirmed|0                           |1

--- Comment #4 from janus at gcc dot gnu.org 2013-01-19 15:14:31 UTC ---
(In reply to comment #2)
> Yet another variant:
> [...]
>
> gives me (four times!):
> 
>       real, dimension(this%getdims()) :: getx
>                       1
> Error: Function 'this' at (1) must be PURE
> 
> 
> which is of course bogus, since 'this' is not even a function, and getdims is
> actually pure.

The wording of the error message can be fixed by this patch:


Index: gcc/fortran/expr.c
===================================================================
--- gcc/fortran/expr.c    (revision 195310)
+++ gcc/fortran/expr.c    (working copy)
@@ -2962,18 +2962,24 @@ gfc_specification_expr (gfc_expr *e)
       return FAILURE;
     }

-  comp = gfc_get_proc_ptr_comp (e);
-  if (e->expr_type == EXPR_FUNCTION
-      && !e->value.function.isym
-      && !e->value.function.esym
-      && !gfc_pure (e->symtree->n.sym)
-      && (!comp || !comp->attr.pure))
+  if (e->expr_type == EXPR_FUNCTION)
     {
-      gfc_error ("Function '%s' at %L must be PURE",
-         e->symtree->n.sym->name, &e->where);
-      /* Prevent repeat error messages.  */
-      e->symtree->n.sym->attr.pure = 1;
-      return FAILURE;
+      comp = gfc_get_proc_ptr_comp (e);
+      if (comp && !comp->attr.pure)
+    {
+      gfc_error ("Procedure pointer component '%s' at %L must be PURE",
+             comp->name, &e->where);
+      return FAILURE;
+    }
+      else if (!comp && !e->value.function.isym && !e->value.function.esym
+           && !gfc_pure (e->symtree->n.sym))
+    {
+      gfc_error ("Function '%s' at %L must be PURE",
+             e->symtree->n.sym->name, &e->where);
+      /* Prevent repeat error messages.  */
+      e->symtree->n.sym->attr.pure = 1;
+      return FAILURE;
+    }
     }

   if (e->rank != 0)



With this ones gets:

      real, dimension(this%getdims()) :: getx
                      1
Error: Procedure pointer component 'getdims' at (1) must be PURE


This still leaves us with some problems:
1) That we get the error at all. The interface of getdims is clearly PURE, but
it seems that its resolution happens too late, so that the attributes have not
yet been copied from the interface when the pureness check is done.
2) getdims is identified as a PPC in the error message, though it is a
type-bound procedure. The reason for this is that internally "this%getdims()"
is resolved to "this->_vptr->getdims" (where getdims is a PPC of _vptr).
3) The error message still comes four times (not sure why).

[Bug fortran/55960] [OOP] ICE in replace_comp, at fortran/expr.c:4356

[janus at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55960

janus at gcc dot gnu.org changed:

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

--- Comment #5 from janus at gcc dot gnu.org ---
Note that 'replace_comp' has been removed in r195562 (cf. PR 54107), with the
consequence that the original ICE on comment 0 is fixed in 4.8.0 and above.

Also the double error message is reduced to a single one in 4.8.

For comment 2, 4.8 actually gives an ICE in mio_expr, but it compiles cleanly
with trunk, so I'm closing this whole PR as fixed.

[Bug fortran/55960] [OOP] ICE in replace_comp, at fortran/expr.c:4356

[loximann at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55960

--- Comment #6 from Sergio Losilla <loximann at gmail dot com> ---
Well, a very similar case, with a non-abstract type throws an ICE with gfortran
4.8.1:

module Foo_class
    type :: Foo
        integer :: n
    contains
        procedure :: n2  => Foo_n2
        procedure :: vec => Foo_vec
    end type

contains

    pure function Foo_n2(self)
        class(Foo), intent(in) :: self
        integer                :: Foo_n2

        Foo_n2 = self%n**2
    end function

    function Foo_vec(self)
        class(Foo) :: self
        real       :: Foo_vec(self%n2())

        Foo_vec=1.0
    end function

end module

[Bug fortran/55960] [OOP] ICE in replace_comp, at fortran/expr.c:4356

[janus at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55960

--- Comment #7 from janus at gcc dot gnu.org ---
(In reply to Sergio Losilla from comment #6)
> Well, a very similar case, with a non-abstract type throws an ICE with
> gfortran 4.8.1:

Right. This comes from mio_expr and seems to be similar or identical to the ICE
that 4.8 throws on comment 2. But both of them are gone with current trunk.