[Bug fortran/33215] Bind(C): Bugs with empty "name=": Creates wrong result and accepts invalid

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

------- Comment #1 from burnus at gcc dot gnu dot org  2007-08-28 10:04 -------
The bug is actually worse as valid Fortran 2003 programs are rejected.

The following program should print "5 -5". The two static global variables are
not the same as their binding name is not "a" but something like "__m_MOD_a"
and "__n_MOD_a".

Somehow the binding is treated wrongly and thus one gets the error:

Error: Binding label 'a' at (1) collides with global entity 'a' at (2)

With NAG f95 the desired "5 -5" is printed. The program below should behave
identically for BIND(C,name="") and without. (Using the variable from C is
difficult, but one could think of passing the variable as actual argument or -
with TARGET attribute - a pointer to that variable.)

module m
  use iso_c_binding
  implicit none
  integer(c_int), save, bind(C, name="") :: a = 5
!  integer(c_int), save :: a = 5
end module m

module n
  use iso_c_binding
  implicit none
  integer(c_int), save, bind(C,name="") :: a = -5
!  integer(c_int), save :: a = -5
end module n

program prog
use m
use n, b=>a
implicit none
  print *, a, b
end program prog


-- 

burnus at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |rejects-valid
            Summary|Bind(C): Accepts multiple   |Bind(C): Bugs with empty
                   |entites with same (empty)   |"name=": Creates wrong
                   |binding name                |result and accepts invalid


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=33215