From b7646403557eca19612c81437f381d4b4dcd51c8 Mon Sep 17 00:00:00 2001
From: Harald Anlauf <anlauf@gmx.de>
Date: Fri, 28 Oct 2022 21:58:08 +0200
Subject: [PATCH] Fortran: ordering of hidden procedure arguments [PR107441]

gcc/fortran/ChangeLog:

	PR fortran/107441
	* trans-decl.cc (create_function_arglist): Adjust the ordering of
	automatically generated hidden procedure arguments to match the
	documented ABI for gfortran.

gcc/testsuite/ChangeLog:

	PR fortran/107441
	* gfortran.dg/optional_absent_6.f90: New test.
---
 gcc/fortran/trans-decl.cc                     | 15 +++--
 .../gfortran.dg/optional_absent_6.f90         | 60 +++++++++++++++++++
 2 files changed, 71 insertions(+), 4 deletions(-)
 create mode 100644 gcc/testsuite/gfortran.dg/optional_absent_6.f90

diff --git a/gcc/fortran/trans-decl.cc b/gcc/fortran/trans-decl.cc
index 63515b9072a..18842fe2c4b 100644
--- a/gcc/fortran/trans-decl.cc
+++ b/gcc/fortran/trans-decl.cc
@@ -2508,7 +2508,7 @@ create_function_arglist (gfc_symbol * sym)
   tree fndecl;
   gfc_formal_arglist *f;
   tree typelist, hidden_typelist;
-  tree arglist, hidden_arglist;
+  tree arglist, hidden_arglist, optional_arglist, strlen_arglist;
   tree type;
   tree parm;

@@ -2518,6 +2518,7 @@ create_function_arglist (gfc_symbol * sym)
      the new FUNCTION_DECL node.  */
   arglist = NULL_TREE;
   hidden_arglist = NULL_TREE;
+  strlen_arglist = optional_arglist = NULL_TREE;
   typelist = TYPE_ARG_TYPES (TREE_TYPE (fndecl));

   if (sym->attr.entry_master)
@@ -2644,7 +2645,7 @@ create_function_arglist (gfc_symbol * sym)
 	  length = build_decl (input_location,
 			       PARM_DECL, get_identifier (name), len_type);

-	  hidden_arglist = chainon (hidden_arglist, length);
+	  strlen_arglist = chainon (strlen_arglist, length);
 	  DECL_CONTEXT (length) = fndecl;
 	  DECL_ARTIFICIAL (length) = 1;
 	  DECL_ARG_TYPE (length) = len_type;
@@ -2712,7 +2713,7 @@ create_function_arglist (gfc_symbol * sym)
 			    PARM_DECL, get_identifier (name),
 			    boolean_type_node);

-          hidden_arglist = chainon (hidden_arglist, tmp);
+	  optional_arglist = chainon (optional_arglist, tmp);
           DECL_CONTEXT (tmp) = fndecl;
           DECL_ARTIFICIAL (tmp) = 1;
           DECL_ARG_TYPE (tmp) = boolean_type_node;
@@ -2863,10 +2864,16 @@ create_function_arglist (gfc_symbol * sym)
       typelist = TREE_CHAIN (typelist);
     }

+  /* Add hidden present status for optional+value arguments.  */
+  arglist = chainon (arglist, optional_arglist);
+
   /* Add the hidden string length parameters, unless the procedure
      is bind(C).  */
   if (!sym->attr.is_bind_c)
-    arglist = chainon (arglist, hidden_arglist);
+    arglist = chainon (arglist, strlen_arglist);
+
+  /* Add hidden extra arguments for the gfortran library.  */
+  arglist = chainon (arglist, hidden_arglist);

   gcc_assert (hidden_typelist == NULL_TREE
               || TREE_VALUE (hidden_typelist) == void_type_node);
diff --git a/gcc/testsuite/gfortran.dg/optional_absent_6.f90 b/gcc/testsuite/gfortran.dg/optional_absent_6.f90
new file mode 100644
index 00000000000..b8abb06980a
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/optional_absent_6.f90
@@ -0,0 +1,60 @@
+! { dg-do run }
+! PR fortran/107441
+!
+! Test VALUE + OPTIONAL for integer/real/...
+! in the presence of non-optional character dummies
+
+program bugdemo
+  implicit none
+  character :: s = 'a'
+  integer   :: t
+
+  t = testoptional(s)
+  call test2 (s)
+  call test3 (s)
+  call test4 (w='123',x=42)
+
+contains
+
+  function testoptional (w, x) result(t)
+    character, intent(in)                  :: w
+    integer,   intent(in), value, optional :: x
+    integer :: t
+    print *, 'present(x) is', present(x)
+    t = 0
+    if (present (x)) stop 1
+  end function testoptional
+
+  subroutine test2 (w, x)
+    character, intent(in)                  :: w
+    integer,   intent(in), value, optional :: x
+    print*, 'present(x) is', present(x)
+    if (present (x)) stop 2
+  end subroutine test2
+
+  subroutine test3 (w, x)
+    character, intent(in),        optional :: w
+    integer,   intent(in), value, optional :: x
+    print *, 'present(w) is', present(w)
+    print *, 'present(x) is', present(x)
+    if (.not. present (w)) stop 3
+    if (present (x)) stop 4
+  end subroutine test3
+
+  subroutine test4 (r, w, x)
+    real,                     value, optional :: r
+    character(*), intent(in),        optional :: w
+    integer,                  value, optional :: x
+    print *, 'present(r) is', present(r)
+    print *, 'present(w) is', present(w)
+    print *, 'present(x) is', present(x)
+    if (present (r)) stop 5
+    if (.not. present (w)) stop 6
+    if (.not. present (x)) stop 7
+    print *, 'x=', x
+    print *, 'len(w)=', len(w)
+    if (len(w) /= 3) stop 8
+    if (x /= 42) stop 9
+  end subroutine test4
+
+end program bugdemo
--
2.35.3