[PATCH] PR fortran/89943 -- BIND(C) procedures in submodules

[Steve Kargl]

The attached patch has been tested on x86_64-*-freebsd.
There were no regressions.

The patch suppresses error messages for function, subroutine,
and entry statements if these appear in a submodule.  The
interface declared in the module must match the interface in
submodule (including the BIND(C) label).

Ok to commit?

2019-08-02  Steven G. Kargl  <ka...@gcc.gnu.org.

        PR fortran/89943
        * decl.c (match_attr_spec): Whitespace.
        (gfc_match_function_decl,gfc_match_entry,gfc_match_subroutine):
        Suppress BIND(C) error messages for declarations in a submodule.
        * symbol.c (gfc_add_is_bind_c): Ditto.

2019-08-02  Steven G. Kargl  <ka...@gcc.gnu.org.

        PR fortran/89943
        * gfortran.dg/pr89943.f90: New test.

-- 
Steve

Index: gcc/fortran/decl.c
===================================================================
--- gcc/fortran/decl.c	(revision 274033)
+++ gcc/fortran/decl.c	(working copy)
@@ -5535,7 +5535,7 @@ match_attr_spec (void)
 	  break;
 
         case DECL_IS_BIND_C:
-           t = gfc_add_is_bind_c(&current_attr, NULL, &seen_at[d], 0);
+           t = gfc_add_is_bind_c (&current_attr, NULL, &seen_at[d], 0);
            break;
 
 	case DECL_VALUE:
@@ -7224,7 +7224,7 @@ gfc_match_function_decl (void)
   /* Make sure that it isn't already declared as BIND(C).  If it is, it
      must have been marked BIND(C) with a BIND(C) attribute and that is
      not allowed for procedures.  */
-  if (sym->attr.is_bind_c == 1)
+  if (sym->attr.is_bind_c == 1 && sym->attr.used_in_submodule == 0)
     {
       sym->attr.is_bind_c = 0;
       if (sym->old_symbol != NULL)
@@ -7483,7 +7483,7 @@ gfc_match_entry (void)
   /* Make sure that it isn't already declared as BIND(C).  If it is, it
      must have been marked BIND(C) with a BIND(C) attribute and that is
      not allowed for procedures.  */
-  if (entry->attr.is_bind_c == 1)
+  if (entry->attr.is_bind_c == 1 && entry->attr.used_in_submodule == 0)
     {
       entry->attr.is_bind_c = 0;
       if (entry->old_symbol != NULL)
@@ -7690,7 +7690,7 @@ gfc_match_subroutine (void)
   /* Make sure that it isn't already declared as BIND(C).  If it is, it
      must have been marked BIND(C) with a BIND(C) attribute and that is
      not allowed for procedures.  */
-  if (sym->attr.is_bind_c == 1)
+  if (sym->attr.is_bind_c == 1 && sym->attr.used_in_submodule == 0)
     {
       sym->attr.is_bind_c = 0;
       if (sym->old_symbol != NULL)
Index: gcc/fortran/symbol.c
===================================================================
--- gcc/fortran/symbol.c	(revision 274032)
+++ gcc/fortran/symbol.c	(working copy)
@@ -1902,7 +1902,7 @@ gfc_add_is_bind_c (symbol_attribute *attr, const char 
   if (is_proc_lang_bind_spec == 0 && attr->flavor == FL_PROCEDURE)
     gfc_error_now ("BIND(C) attribute at %L can only be used for "
 		   "variables or common blocks", where);
-  else if (attr->is_bind_c)
+  else if (attr->is_bind_c && attr->used_in_submodule == 0)
     gfc_error_now ("Duplicate BIND attribute specified at %L", where);
   else
     attr->is_bind_c = 1;
Index: gcc/testsuite/gfortran.dg/pr89943.f90
===================================================================
--- gcc/testsuite/gfortran.dg/pr89943.f90	(nonexistent)
+++ gcc/testsuite/gfortran.dg/pr89943.f90	(working copy)
@@ -0,0 +1,28 @@
+! { dg-do compile}
+! Original code submitted by Alberto Luaces <aluaces at udc dot es>
+module Foo_mod
+
+   implicit none
+
+   interface
+      module subroutine runFoo4C(ndim) bind(C, name="runFoo")
+         use, intrinsic :: iso_c_binding
+         implicit none
+         integer(c_int32_t) , intent(in) :: ndim
+      end subroutine runFoo4C
+   end interface
+
+   contains
+end module Foo_mod
+
+submodule (Foo_mod) Foo_smod
+
+contains
+
+   module subroutine runFoo4C(ndim) bind(C, name="runFoo")
+      use, intrinsic :: iso_c_binding
+      implicit none
+      integer(c_int32_t) , intent(in) :: ndim
+   end subroutine runFoo4C
+
+end submodule Foo_smod