[Bug fortran/54884] [4.8 Regression] Externally used PRIVATE module procedure wrongly marked as TREE_PUBLIC()=0

["burnus at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54884

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|RESOLVED                    |REOPENED
   Last reconfirmed|                            |2012-12-19
         Resolution|FIXED                       |
     Ever Confirmed|0                           |1

--- Comment #9 from Tobias Burnus <burnus at gcc dot gnu.org> 2012-12-19 18:20:10 UTC ---
First: I think one should add a pass to frontend-passes.c, similar to 
doloop_code. The reason is that resolve comes too early for some checks.
Quoting from resolve.c:

  /* If a PRIVATE variable is used in the specification expression of the
     result variable, it might be accessed from outside the module and can
     thus not be TREE_PUBLIC() = 0.
     TODO: sym->attr.public_used only has to be set for the result variable's
     type-parameter expression and not for dummies or automatic variables.
     Additionally, it only has to be set if the function is either PUBLIC or
     used in a generic interface or TBP; unfortunately,
     proc_name->attr.public_used can get set at a later stage.  */


Secondly, a reducted test case for the FoX issue of comment 7 is the following:

module m
  private
  public :: foo
  interface foo
    module procedure bar
  end interface foo
contains
  pure function mylen()
    integer :: mylen
    mylen = 42
  end function mylen
  subroutine bar(x)
    character(len=mylen()) :: x
  end subroutine bar
end module m


The following line in resolve.c's resolve_function should take care of setting
the public_use attribute, but it doesn't work:

3128      if (sym && specification_expr && sym->attr.function
3129          && gfc_current_ns->proc_name
3130          && gfc_current_ns->proc_name->attr.flavor == FL_MODULE)
3131        sym->attr.public_used = 1;

The reason is that

(gdb) p gfc_current_ns->proc_name->name
$6 = 0x7ffff6725fe0 "bar"