[Bug fortran/53655] New: []

[Bug fortran/53655] New: []

[burnus at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53655

             Bug #: 53655
           Summary: []
    Classification: Unclassified
           Product: gcc
           Version: 4.8.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: fortran
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: burnus@gcc.gnu.org

[Bug fortran/53655] [OOP] CLASS-related warnings: "__copy" defined but not used; "default initializer" warnings

[burnus at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53655

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |diagnostic
                 CC|                            |burnus at gcc dot gnu.org
            Summary|[]                          |[OOP] CLASS-related
                   |                            |warnings: "__copy" defined
                   |                            |but not used; "default
                   |                            |initializer" warnings

--- Comment #1 from Tobias Burnus <burnus at gcc dot gnu.org> 2012-06-13 09:18:40 UTC ---
The following code has several warning issues:

a) For foo's "x" there is the warning:
"Derived-type dummy argument 'x' at (1) was declared INTENT(OUT) but was not
set and does not have a default initializer"
As "t" has no components, the warning doesn't make sense.

b) For bar's "x" there is no warning as it is sym->attr.referenced, but I think
one should warn that the "declared type" does not have an initializer.
(I think sym->attr.referenced gets set for "allocatable" dummies, thus, no
warning is printed.)

c) One gets the bogus error:
  warning: ‘__copy_MAIN___T2’ defined but not used [-Wunused-function]
It probably should be marked as DECL_ARTIFICIAL().


type t
end type t

type t2
  integer :: i
end type t2
contains
  subroutine foo(x)
    type(t), intent(out) :: x
  end subroutine foo

  subroutine bar(x)
    class(t2), intent(out) :: x
  end subroutine bar
end

[Bug fortran/53655] [OOP] CLASS-related warnings: "__copy" defined but not used; "default initializer" warnings

[burnus at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53655

--- Comment #2 from Tobias Burnus <burnus at gcc dot gnu.org> 2012-06-13 09:20:56 UTC ---
(In reply to comment #1)
> (I think sym->attr.referenced gets set for "allocatable" dummies, thus, no
> warning is printed.)

(As clarification: That wasn't a remark to the issue (b) but a general one.
Note that for allocatables, no warning initializer-related warning should be be
printed. Thus, the current result is okay.)

[Bug fortran/53655] [OOP] CLASS-related warnings: "__copy" defined but not used; "default initializer" warnings

[janus at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53655

janus at gcc dot gnu.org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2013-08-19
                 CC|                            |janus at gcc dot gnu.org
     Ever confirmed|0                           |1

--- Comment #3 from janus at gcc dot gnu.org ---
(In reply to Tobias Burnus from comment #1)
> c) One gets the bogus error:
>   warning: ‘__copy_MAIN___T2’ defined but not used [-Wunused-function]
> It probably should be marked as DECL_ARTIFICIAL().

This problem has apparently been fixed at some point. I see it neither with
4.7.4, 4.8.2 nor with trunk.
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From: "janus at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug fortran/53655] [OOP] CLASS-related warnings: "__copy" defined but not used; "default initializer" warnings
Date: Mon, 19 Aug 2013 15:04:00 -0000
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http://gcc.gnu.org/bugzilla/show_bug.cgi?idS655

--- Comment #4 from janus at gcc dot gnu.org ---
(In reply to Tobias Burnus from comment #1)
> a) For foo's "x" there is the warning:
> "Derived-type dummy argument 'x' at (1) was declared INTENT(OUT) but was not
> set and does not have a default initializer"
> As "t" has no components, the warning doesn't make sense.

This is easily fixed by the following:

Index: gcc/fortran/trans-decl.c
==================================================================--- gcc/fortran/trans-decl.c    (revision 201834)
+++ gcc/fortran/trans-decl.c    (working copy)
@@ -4745,7 +4745,8 @@
         gfc_warning ("Dummy argument '%s' at %L was declared "
                  "INTENT(OUT) but was not set",  sym->name,
                  &sym->declared_at);
-          else if (!gfc_has_default_initializer (sym->ts.u.derived))
+          else if (!gfc_has_default_initializer (sym->ts.u.derived)
+               && !sym->ts.u.derived->attr.zero_comp)
         gfc_warning ("Derived-type dummy argument '%s' at %L was "
                  "declared INTENT(OUT) but was not set and "
                  "does not have a default initializer",

[Bug fortran/53655] [OOP] CLASS-related warnings: "__copy" defined but not used; "default initializer" warnings

[janus at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53655

--- Comment #5 from janus at gcc dot gnu.org ---
(In reply to Tobias Burnus from comment #1)
> b) For bar's "x" there is no warning as it is sym->attr.referenced, but I
> think one should warn that the "declared type" does not have an initializer.

With 4.9 trunk, the following code is generated for 'bar':


bar (struct __class_MAIN___T2 & restrict x)
{
  if (x->_vptr->_final != 0B)
    {
      {
        struct array0_unknown desc.0;

        desc.0.dtype = 600;
        desc.0.data = (void * restrict) x->_data;
        x->_vptr->_final (&desc.0, x->_vptr->_size, 0);
      }
    }
  (void) __builtin_memcpy ((void *) x->_data, (void *) x->_vptr->_def_init,
(unsigned long) x->_vptr->_size);
}


The _final call is new in 4.9, but the memcpy from _def_init appeared already
with 4.7 and 4.8. (Possibly this is what sets sym->referenced?)


However, I'm not convinced that one should throw a warning here: Even if the
declared type does not have a default initializer, an extended type might have
one and of course we don't know the actual (dynamic) type of the class variable
at compile time (that's why we have the _def_init after all).

[Bug fortran/53655] [OOP] "default initializer" warnings

[janus at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53655

janus at gcc dot gnu.org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |ASSIGNED
           Assignee|unassigned at gcc dot gnu.org      |janus at gcc dot gnu.org
            Summary|[OOP] CLASS-related         |[OOP] "default initializer"
                   |warnings: "__copy" defined  |warnings
                   |but not used; "default      |
                   |initializer" warnings       |

--- Comment #6 from janus at gcc dot gnu.org ---
The patch in comment 4 regtests cleanly. Will commit as obvious.