--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gcc/ada/bindo-elaborators.ads	Thu Feb 13 11:34:05 2020 +0900
@@ -0,0 +1,55 @@
+------------------------------------------------------------------------------
+--                                                                          --
+--                         GNAT COMPILER COMPONENTS                         --
+--                                                                          --
+--                     B I N D O . E L A B O R A T O R S                    --
+--                                                                          --
+--                                 S p e c                                  --
+--                                                                          --
+--             Copyright (C) 2019, Free Software Foundation, Inc.           --
+--                                                                          --
+-- GNAT is free software;  you can  redistribute it  and/or modify it under --
+-- terms of the  GNU General Public License as published  by the Free Soft- --
+-- ware  Foundation;  either version 3,  or (at your option) any later ver- --
+-- sion.  GNAT is distributed in the hope that it will be useful, but WITH- --
+-- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --
+-- or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License --
+-- for  more details.  You should have  received  a copy of the GNU General --
+-- Public License  distributed with GNAT; see file COPYING3.  If not, go to --
+-- http://www.gnu.org/licenses for a complete copy of the license.          --
+--                                                                          --
+-- GNAT was originally developed  by the GNAT team at  New York University. --
+-- Extensive contributions were provided by Ada Core Technologies Inc.      --
+--                                                                          --
+------------------------------------------------------------------------------
+
+--  For full architecture, see unit Bindo.
+
+--  The following unit contains facilities to find the elaboration order of
+--  units based on various graphs.
+
+with Bindo.Graphs;
+use  Bindo.Graphs;
+use  Bindo.Graphs.Invocation_Graphs;
+use  Bindo.Graphs.Library_Graphs;
+
+package Bindo.Elaborators is
+
+   ----------------------------------------------
+   -- Invocation_And_Library_Graph_Elaborators --
+   ----------------------------------------------
+
+   package Invocation_And_Library_Graph_Elaborators is
+      procedure Elaborate_Units
+        (Order         : out Unit_Id_Table;
+         Main_Lib_File : File_Name_Type);
+      --  Find an order of all units in the bind that need to be elaborated
+      --  such that elaboration code flow, pragmas Elaborate, Elaborate_All,
+      --  and Elaborate_Body, and with clause dependencies are all honoured.
+      --  Main_Lib_File is the argument of the bind. If a satisfactory order
+      --  exists, it is returned in Order, otherwise Unrecoverable_Error is
+      --  raised.
+
+   end Invocation_And_Library_Graph_Elaborators;
+
+end Bindo.Elaborators;