[Patch, fortran] PR82550 - program using submodules fails to link

[Paul Richard Thomas]

The attached patch has a comment that explains what is going on.

Bootstrapped and regtested on FC23/x86_64 - OK for trunk and 7-branch?

Paul

2017-10-17  Paul Thomas  <pault@gcc.gnu.org>

    PR fortran/82550
    * expr.c (gfc_check_pointer_assign): A use associated procedure
    target in a submodule must have the 'use_assoc' attribute set
    so that the name mangling is done correctly.

2017-10-17  Paul Thomas  <pault@gcc.gnu.org>

    PR fortran/82550
    * gfortran.dg/submodule_30.f08 : New test.


-- 
"If you can't explain it simply, you don't understand it well enough"
- Albert Einstein
-------------- next part --------------
Index: gcc/fortran/expr.c
===================================================================
*** gcc/fortran/expr.c	(revision 253748)
--- gcc/fortran/expr.c	(working copy)
*************** gfc_check_pointer_assign (gfc_expr *lval
*** 3632,3637 ****
--- 3632,3645 ----
  	  name = s2->name;
  	}
  
+       /* Make the procedure use associated so that the middle end does
+ 	 the right thing with name mangling. This undoes the reset in
+ 	 parse.c(set_syms_host_assoc) and is necessary to allow the
+ 	 attributes of module procedure interfaces to be changed.  */
+       if (s2 && s2->attr.flavor == FL_PROCEDURE
+ 	  && s2->module && s2->attr.used_in_submodule)
+ 	s2->attr.use_assoc = 1;
+ 
        if (s2 && s2->attr.proc_pointer && s2->ts.interface)
  	s2 = s2->ts.interface;
  
Index: gcc/testsuite/gfortran.dg/submodule_30.f08
===================================================================
*** gcc/testsuite/gfortran.dg/submodule_30.f08	(nonexistent)
--- gcc/testsuite/gfortran.dg/submodule_30.f08	(working copy)
***************
*** 0 ****
--- 1,42 ----
+ ! { dg-do run }
+ !
+ ! Test the fix for PR82550 in which the reference to 'p' in 'foo'
+ ! was not being correctly handled.
+ !
+ ! Contributed by Reinhold Bader  <Bader@lrz.de>
+ !
+ module m_subm_18_pos
+   implicit none
+   integer :: i = 0
+   interface
+     module subroutine foo(fun_ptr)
+       procedure(p), pointer, intent(out) :: fun_ptr
+     end subroutine
+   end interface
+ contains
+   subroutine p()
+     i = 1
+   end subroutine p
+ end module m_subm_18_pos
+ submodule (m_subm_18_pos) subm_18_pos
+     implicit none
+ contains
+     module subroutine foo(fun_ptr)
+       procedure(p), pointer, intent(out) :: fun_ptr
+       fun_ptr => p
+     end subroutine
+ end submodule
+ program p_18_pos
+   use m_subm_18_pos
+   implicit none
+   procedure(), pointer :: x
+   call foo(x)
+   call x()
+   if (i == 1) then
+      write(*,*) 'OK'
+   else
+      write(*,*) 'FAIL'
+      call abort
+   end if
+ end program p_18_pos
+