[Bug fortran/54221] New: Explicit private access specifier signals "unexpected defined but not used [-Wunused-function]" warning

[Bug fortran/54221] New: Explicit private access specifier signals "unexpected defined but not used [-Wunused-function]" warning

[koen.poppe at cs dot kuleuven.be]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54221

             Bug #: 54221
           Summary: Explicit private access specifier signals "unexpected
                    defined but not used [-Wunused-function]" warning
    Classification: Unclassified
           Product: gcc
           Version: 4.8.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: fortran
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: koen.poppe@cs.kuleuven.be


Created attachment 27982
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=27982
Reproduces unexpected warning on compilation

Setting routines private in a private module causes the "defined but not used
[-Wunused-function]" warning to be issued.

[Bug fortran/54221] Explicit private access specifier signals "unexpected defined but not used [-Wunused-function]" warning

[burnus at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54221

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |diagnostic
                 CC|                            |burnus at gcc dot gnu.org

--- Comment #1 from Tobias Burnus <burnus at gcc dot gnu.org> 2012-08-10 15:35:40 UTC ---
I think there are two issues:

a) There is a bogus warning. I think that's a middle-end bug

b) The same warning should be triggered for "PRIVATE" and for "PRIVATE ::
hello_integer"

However, the Fortran front end only checks sym->attr.access == ACCESS_PRIVATE,
which obviously doesn't get set by "PRIVATE". (See patch below.) That's a
missed-optimization issue.


Simplified example (compile with -Wall or -Wunused-function):

module mod_say_hello
    private :: hello_integer
contains
    subroutine say_hello()
        call hello_integer(123)
    end subroutine say_hello
    subroutine hello_integer( a )
        integer, intent(in) ::  a
        print *, "Hello ", a, "!"
    end subroutine hello_integer
end module mod_say_hello


Patch for issue (b):

--- a/gcc/fortran/trans-decl.c
+++ b/gcc/fortran/trans-decl.c
@@ -1841,2 +1841,9 @@ build_function_decl (gfc_symbol * sym, bool global)

+  if (sym->attr.access == ACCESS_UNKNOWN
+      && sym->ns->proc_name && sym->ns->proc_name->attr.flavor == FL_MODULE
+      && (sym->ns->default_access == ACCESS_PRIVATE
+         || (sym->ns->default_access == ACCESS_UNKNOWN
+             && gfc_option.flag_module_private)))
+    sym->attr.access = ACCESS_PRIVATE;
+
   if (!current_function_decl

[Bug fortran/54221] Explicit private access specifier signals "unexpected defined but not used [-Wunused-function]" warning

[burnus at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54221

--- Comment #2 from Tobias Burnus <burnus at gcc dot gnu.org> 2012-08-11 09:06:21 UTC ---
(In reply to comment #1)
> a) There is a bogus warning. I think that's a middle-end bug
See PR 54224.

> Patch for issue (b):
Seems to work. One might have to do likewise for module variables
(gfc_finish_var_decl), cf. PR52751. [The original code has been added for
PR40973 and fixed for PR52916.]

[Bug fortran/54221] Explicit private access specifier signals "unexpected defined but not used [-Wunused-function]" warning

[burnus at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54221

--- Comment #3 from Tobias Burnus <burnus at gcc dot gnu.org> 2012-08-12 09:52:36 UTC ---
Author: burnus
Date: Sun Aug 12 09:52:33 2012
New Revision: 190325

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=190325
Log:
2012-08-12  Tobias Burnus  <burnus@net-b.de>

        PR fortran/54221
        * trans-decl.c (gfc_finish_var_decl, build_function_decl):
        Fix setting private module vars/procs as TREE_PUBLIC(...) = 0.

2012-08-12  Tobias Burnus  <burnus@net-b.de>

        PR fortran/54221
        * vect/vect-gems.f90: Don't mark module vars as PRIVATE as
        they appear uninitialized on the RHS.
        * gfortran.dg/public_private_module_6.f90: New.


Added:
    trunk/gcc/testsuite/gfortran.dg/public_private_module_6.f90
Modified:
    trunk/gcc/fortran/ChangeLog
    trunk/gcc/fortran/trans-decl.c
    trunk/gcc/testsuite/ChangeLog
    trunk/gcc/testsuite/gfortran.dg/vect/vect-gems.f90

[Bug fortran/54221] [4.8 Regression] Explicit private access specifier signals "unexpected defined but not used [-Wunused-function]" warning

[burnus at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54221

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Priority|P3                          |P4
   Target Milestone|---                         |4.8.0
            Summary|Explicit private access     |[4.8 Regression] Explicit
                   |specifier signals           |private access specifier
                   |"unexpected defined but not |signals "unexpected defined
                   |used [-Wunused-function]"   |but not used
                   |warning                     |[-Wunused-function]"
                   |                            |warning

--- Comment #4 from Tobias Burnus <burnus at gcc dot gnu.org> 2012-08-21 08:53:48 UTC ---
I mark this now as regression in the Fortran front-end to keep better track of
PR middle-end/54224: It seems as if part of the fix has to be done in the
Fortran front-end.

In this PR, the issue of having a different result with PRIVATE vs. "PRIVATE ::
entry_name" is now fixed.

It remains the issue that there is no warning for unused internal procedures
(or unused nested functions in C), no warning of unused PRIVATE module
variables and a spurious warning for *used* PRIVATE module procedures. Those
are tracked in PR 54224. Additionally, there is the issue that the private
module procedures is not inlined, see other PR and PR 48636 comment 18.

[Bug fortran/54221] [4.8 Regression] Explicit private access specifier signals "unexpected defined but not used [-Wunused-function]" warning

[janus at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54221

janus at gcc dot gnu.org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |janus at gcc dot gnu.org

--- Comment #5 from janus at gcc dot gnu.org 2012-10-09 19:53:45 UTC ---
(In reply to comment #3)
> Author: burnus
> Date: Sun Aug 12 09:52:33 2012
> New Revision: 190325
> 
> URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=190325

Seems like this caused:

http://gcc.gnu.org/ml/fortran/2012-10/msg00046.html

[Bug fortran/54221] [4.8/4.9 Regression] Explicit private access specifier signals "unexpected defined but not used [-Wunused-function]" warning

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54221

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|4.8.0                       |4.8.1

--- Comment #6 from Jakub Jelinek <jakub at gcc dot gnu.org> 2013-03-22 14:44:27 UTC ---
GCC 4.8.0 is being released, adjusting target milestone.

[Bug fortran/54221] [4.8/4.9 Regression] Explicit private access specifier signals "unexpected defined but not used [-Wunused-function]" warning

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54221

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|4.8.1                       |4.8.2

--- Comment #7 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
GCC 4.8.1 has been released.

[Bug fortran/54221] [4.8/4.9 Regression] Explicit private access specifier signals "unexpected defined but not used [-Wunused-function]" warning

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54221

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|4.8.2                       |4.8.3

--- Comment #8 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
GCC 4.8.2 has been released.

[Bug fortran/54221] [4.8/4.9 Regression] Explicit private access specifier signals "unexpected defined but not used [-Wunused-function]" warning

[dominiq at lps dot ens.fr]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54221

Dominique d'Humieres <dominiq at lps dot ens.fr> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |WAITING
   Last reconfirmed|                            |2013-12-29
     Ever confirmed|0                           |1

--- Comment #9 from Dominique d'Humieres <dominiq at lps dot ens.fr> ---
> I mark this now as regression in the Fortran front-end to keep better track 
> of PR middle-end/54224: It seems as if part of the fix has to be done 
> in the Fortran front-end.
>
> In this PR, the issue of having a different result with PRIVATE vs. 
> "PRIVATE :: entry_name" is now fixed.

I don't see the point to keep this PR open in addition of pr54224 (only one
issue left AFAIU). Also I don't think this is any longer a regression.

[Bug fortran/54221] [4.8/4.9 Regression] Explicit private access specifier signals "unexpected defined but not used [-Wunused-function]" warning

[janus at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54221

janus at gcc dot gnu.org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |abensonca at gmail dot com

--- Comment #10 from janus at gcc dot gnu.org ---
(In reply to Dominique d'Humieres from comment #9)
> I don't see the point to keep this PR open in addition of pr54224 (only one
> issue left AFAIU). Also I don't think this is any longer a regression.

I agree that this PR can probably be closed.

Except: What happened to the problem of comment 5, i.e. the linking problems
with the FoX library? This is apparently the reason for the 'regression' tag. I
see no follow-ups to this either here or in the mailing list thread. Has it
been fixed? Or was it just false alarm?

Andrew, can you give as a comment about what happened to the linking problem?

[Bug fortran/54221] [4.8/4.9 Regression] Explicit private access specifier signals "unexpected defined but not used [-Wunused-function]" warning

[abensonca at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54221

--- Comment #11 from Andrew Benson <abensonca at gmail dot com> ---
(In reply to janus from comment #10)
> (In reply to Dominique d'Humieres from comment #9)
> > I don't see the point to keep this PR open in addition of pr54224 (only one
> > issue left AFAIU). Also I don't think this is any longer a regression.
> 
> I agree that this PR can probably be closed.
> 
> Except: What happened to the problem of comment 5, i.e. the linking problems
> with the FoX library? This is apparently the reason for the 'regression'
> tag. I see no follow-ups to this either here or in the mailing list thread.
> Has it been fixed? Or was it just false alarm?
> 
> Andrew, can you give as a comment about what happened to the linking problem?

This was fixed in PR54884 if I remember correctly.

[Bug fortran/54221] [4.8/4.9 Regression] Explicit private access specifier signals "unexpected defined but not used [-Wunused-function]" warning

[janus at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54221

janus at gcc dot gnu.org changed:

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

--- Comment #12 from janus at gcc dot gnu.org ---
(In reply to Andrew Benson from comment #11)
> This was fixed in PR54884 if I remember correctly.

Ok, thanks.

Then I'm closing this one ...

[Bug fortran/54221] [4.8/4.9 Regression] Explicit private access specifier signals "unexpected defined but not used [-Wunused-function]" warning

[dominiq at lps dot ens.fr]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=54221
Bug 54221 depends on bug 54224, which changed state.

Bug 54224 Summary: Warn for unused internal procedures
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=54224

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

[Bug fortran/54221] [4.8/4.9 Regression] Explicit private access specifier signals "unexpected defined but not used [-Wunused-function]" warning

[dominiq at lps dot ens.fr]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=54221

--- Comment #13 from Dominique d'Humieres <dominiq at lps dot ens.fr> ---
> I agree that this PR can probably be closed.

Closing as FIXED. Please file new PR(s) for new issue(s).

[Bug fortran/54221] [4.8/4.9 Regression] Explicit private access specifier signals "unexpected defined but not used [-Wunused-function]" warning

[dominiq at lps dot ens.fr]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=54221
Bug 54221 depends on bug 54224, which changed state.

Bug 54224 Summary: Warn for unused internal procedures
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=54224

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