[Patch, fortran] PR91926 - assumed rank optional

[Paul Richard Thomas <paul.richard.thomas@gmail.com>]

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Please find attached a patch to keep 9-branch up to speed with trunk
as far as the ISO_Fortran_binding feature is concerned.

It bootstraps and regtests on 9-branch and incorporates the correction
for PR92027, which caused problems for trunk on certain platforms.

OK to commit?

Paul

2019-10-21  Paul Thomas  <pault@gcc.gnu.org>

    Backport from trunk
    PR fortran/91926
    * trans-expr.c (gfc_conv_gfc_desc_to_cfi_desc): Correct the
    assignment of the attribute field to account correctly for an
    assumed shape dummy. Assign separately to the gfc and cfi
    descriptors since the atribute can be different. Add branch to
    correctly handle missing optional dummies.

2019-10-21  Paul Thomas  <pault@gcc.gnu.org>

    Backport from trunk
    PR fortran/91926
    * gfortran.dg/ISO_Fortran_binding_13.f90 : New test.
    * gfortran.dg/ISO_Fortran_binding_13.c : Additional source.
    * gfortran.dg/ISO_Fortran_binding_14.f90 : New test.

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Index: gcc/fortran/trans-expr.c
===================================================================
*** gcc/fortran/trans-expr.c	(revision 276015)
--- gcc/fortran/trans-expr.c	(working copy)
*************** gfc_conv_gfc_desc_to_cfi_desc (gfc_se *p
*** 4989,4995 ****
--- 5006,5014 ----
    tree gfc_desc_ptr;
    tree type;
    tree cond;
+   tree desc_attr;
    int attribute;
+   int cfi_attribute;
    symbol_attribute attr = gfc_expr_attr (e);
    stmtblock_t block;

*************** gfc_conv_gfc_desc_to_cfi_desc (gfc_se *p
*** 4998,5009 ****
    attribute = 2;
    if (!e->rank || gfc_get_full_arrayspec_from_expr (e))
      {
!       if (fsym->attr.pointer)
  	attribute = 0;
!       else if (fsym->attr.allocatable)
  	attribute = 1;
      }

    if (e->rank != 0)
      {
        parmse->force_no_tmp = 1;
--- 5017,5036 ----
    attribute = 2;
    if (!e->rank || gfc_get_full_arrayspec_from_expr (e))
      {
!       if (attr.pointer)
  	attribute = 0;
!       else if (attr.allocatable)
  	attribute = 1;
      }

+   /* If the formal argument is assumed shape and neither a pointer nor
+      allocatable, it is unconditionally CFI_attribute_other.  */
+   if (fsym->as->type == AS_ASSUMED_SHAPE
+       && !fsym->attr.pointer && !fsym->attr.allocatable)
+    cfi_attribute = 2;
+   else
+    cfi_attribute = attribute;
+
    if (e->rank != 0)
      {
        parmse->force_no_tmp = 1;
*************** gfc_conv_gfc_desc_to_cfi_desc (gfc_se *p
*** 5070,5080 ****
  						    parmse->expr, attr);
      }

!   /* Set the CFI attribute field.  */
!   tmp = gfc_conv_descriptor_attribute (parmse->expr);
    tmp = fold_build2_loc (input_location, MODIFY_EXPR,
! 			 void_type_node, tmp,
! 			 build_int_cst (TREE_TYPE (tmp), attribute));
    gfc_add_expr_to_block (&parmse->pre, tmp);

    /* Now pass the gfc_descriptor by reference.  */
--- 5097,5108 ----
  						    parmse->expr, attr);
      }

!   /* Set the CFI attribute field through a temporary value for the
!      gfc attribute.  */
!   desc_attr = gfc_conv_descriptor_attribute (parmse->expr);
    tmp = fold_build2_loc (input_location, MODIFY_EXPR,
! 			 void_type_node, desc_attr,
! 			 build_int_cst (TREE_TYPE (desc_attr), cfi_attribute));
    gfc_add_expr_to_block (&parmse->pre, tmp);

    /* Now pass the gfc_descriptor by reference.  */
*************** gfc_conv_gfc_desc_to_cfi_desc (gfc_se *p
*** 5092,5097 ****
--- 5120,5131 ----
  			     gfor_fndecl_gfc_to_cfi, 2, tmp, gfc_desc_ptr);
    gfc_add_expr_to_block (&parmse->pre, tmp);

+   /* Now set the gfc descriptor attribute.  */
+   tmp = fold_build2_loc (input_location, MODIFY_EXPR,
+ 			 void_type_node, desc_attr,
+ 			 build_int_cst (TREE_TYPE (desc_attr), attribute));
+   gfc_add_expr_to_block (&parmse->pre, tmp);
+
    /* The CFI descriptor is passed to the bind_C procedure.  */
    parmse->expr = cfi_desc_ptr;

*************** gfc_conv_gfc_desc_to_cfi_desc (gfc_se *p
*** 5112,5117 ****
--- 5146,5170 ----
    tmp = build_call_expr_loc (input_location,
  			     gfor_fndecl_cfi_to_gfc, 2, gfc_desc_ptr, tmp);
    gfc_prepend_expr_to_block (&parmse->post, tmp);
+
+   /* Deal with an optional dummy being passed to an optional formal arg
+      by finishing the pre and post blocks and making their execution
+      conditional on the dummy being present.  */
+   if (fsym->attr.optional && e->expr_type == EXPR_VARIABLE
+       && e->symtree->n.sym->attr.optional)
+     {
+       cond = gfc_conv_expr_present (e->symtree->n.sym);
+       tmp = fold_build2 (MODIFY_EXPR, void_type_node,
+ 			 cfi_desc_ptr,
+ 			 build_int_cst (pvoid_type_node, 0));
+       tmp = build3_v (COND_EXPR, cond,
+ 		      gfc_finish_block (&parmse->pre), tmp);
+       gfc_add_expr_to_block (&parmse->pre, tmp);
+       tmp = build3_v (COND_EXPR, cond,
+ 		      gfc_finish_block (&parmse->post),
+ 		      build_empty_stmt (input_location));
+       gfc_add_expr_to_block (&parmse->post, tmp);
+     }
  }


Index: gcc/testsuite/gfortran.dg/ISO_Fortran_binding_13.c
===================================================================
*** gcc/testsuite/gfortran.dg/ISO_Fortran_binding_13.c	(nonexistent)
--- gcc/testsuite/gfortran.dg/ISO_Fortran_binding_13.c	(working copy)
***************
*** 0 ****
--- 1,12 ----
+ /* Test the fix for PR91926.  */
+
+ /* Contributed by José Rui Faustino de Sousa  <jrfsousa@hotmail.com> */
+
+ #include <stdlib.h>
+
+ int ifb_echo(void*);
+
+ int ifb_echo(void *this)
+ {
+   return this == NULL ? 1 : 2;
+ }
Index: gcc/testsuite/gfortran.dg/ISO_Fortran_binding_13.f90
===================================================================
*** gcc/testsuite/gfortran.dg/ISO_Fortran_binding_13.f90	(nonexistent)
--- gcc/testsuite/gfortran.dg/ISO_Fortran_binding_13.f90	(working copy)
***************
*** 0 ****
--- 1,39 ----
+ ! { dg-do run { target c99_runtime } }
+ ! { dg-additional-sources ISO_Fortran_binding_13.c }
+ !
+ ! Test the fix for PR91926. The additional source is the main program.
+ !
+ ! Contributed by José Rui Faustino de Sousa  <jrfsousa@hotmail.com>
+ !
+ program ifb_p
+
+   implicit none
+
+   integer :: i = 42
+
+   interface
+     integer function ifb_echo_aux(this) bind(c, name="ifb_echo")
+       implicit none
+       type(*), dimension(..), & ! removing assumed rank solves segmentation fault
+         optional, intent(in) :: this
+     end function ifb_echo_aux
+   end interface
+
+   if (ifb_echo_aux() .ne. 1) STOP 1  ! worked
+   if (ifb_echo() .ne. 1) stop 2      ! segmentation fault
+   if (ifb_echo_aux(i) .ne. 2) stop 3 ! worked
+   if (ifb_echo(i) .ne. 2) stop 4     ! worked
+
+   stop
+
+ contains
+
+   integer function ifb_echo(this)
+     type(*), dimension(..), &
+       optional, intent(in) :: this
+
+     ifb_echo = ifb_echo_aux(this)
+     return
+   end function ifb_echo
+
+ end program ifb_p
Index: gcc/testsuite/gfortran.dg/ISO_Fortran_binding_14.f90
===================================================================
*** gcc/testsuite/gfortran.dg/ISO_Fortran_binding_14.f90	(nonexistent)
--- gcc/testsuite/gfortran.dg/ISO_Fortran_binding_14.f90	(working copy)
***************
*** 0 ****
--- 1,41 ----
+ ! { dg-do run }
+ !
+ ! Correct an error in the eveluation of the CFI descriptor attribute for
+ ! the case where the bind_C formal argument is not an assumed shape array
+ ! and not allocatable or pointer.
+ !
+ ! Contributed by Gilles Gouaillardet  <gilles@rist.or.jp>
+ !
+ MODULE FOO
+ INTERFACE
+ SUBROUTINE dummy(buf) BIND(C, name="sync")
+ type(*), dimension(..) :: buf
+ END SUBROUTINE
+ END INTERFACE
+ END MODULE
+
+ PROGRAM main
+     USE FOO
+     IMPLICIT NONE
+     integer(8) :: before, after
+
+     INTEGER, parameter :: n = 1
+
+     INTEGER, ALLOCATABLE :: buf(:)
+     INTEGER :: buf2(n)
+     INTEGER :: i
+
+     ALLOCATE(buf(n))
+     before = LOC(buf(1))
+     CALL dummy (buf)
+     after = LOC(buf(1))
+
+     if (before .NE. after) stop 1
+
+     before = LOC(buf2(1))
+     CALL dummy (buf)
+     after = LOC(buf2(1))
+
+     if (before .NE. after) stop 2
+
+ END PROGRAM