--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gcc/ada/libgnat/s-boustr.ads	Fri Oct 27 22:46:09 2017 +0900
@@ -0,0 +1,62 @@
+------------------------------------------------------------------------------
+--                                                                          --
+--                         GNAT RUN-TIME COMPONENTS                         --
+--                                                                          --
+--                S Y S T E M . B O U N D E D _ S T R I N G S               --
+--                                                                          --
+--                                 S p e c                                  --
+--                                                                          --
+--                       Copyright (C) 2016-2017, AdaCore                   --
+--                                                                          --
+-- 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.                                     --
+--                                                                          --
+-- As a special exception under Section 7 of GPL version 3, you are granted --
+-- additional permissions described in the GCC Runtime Library Exception,   --
+-- version 3.1, as published by the Free Software Foundation.               --
+--                                                                          --
+-- You should have received a copy of the GNU General Public License and    --
+-- a copy of the GCC Runtime Library Exception along with this program;     --
+-- see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see    --
+-- <http://www.gnu.org/licenses/>.                                          --
+--                                                                          --
+-- GNAT was originally developed  by the GNAT team at  New York University. --
+-- Extensive contributions were provided by Ada Core Technologies Inc.      --
+--                                                                          --
+------------------------------------------------------------------------------
+
+--  A very simple implentation of bounded strings, used by tracebacks
+
+package System.Bounded_Strings is
+   type Bounded_String (Max_Length : Natural) is limited private;
+   --  A string whose length is bounded by Max_Length. The bounded string is
+   --  empty at initialization.
+
+   procedure Append (X : in out Bounded_String; C : Character);
+   procedure Append (X : in out Bounded_String; S : String);
+   --  Append a character or a string to X. If the bounded string is full,
+   --  extra characters are simply dropped.
+
+   function To_String (X : Bounded_String) return String;
+   function "+" (X : Bounded_String) return String renames To_String;
+   --  Convert to a normal string
+
+   procedure Append_Address (X : in out Bounded_String; A : Address);
+   --  Append an address to X
+
+   function Is_Full (X : Bounded_String) return Boolean;
+   --  Return True iff X is full and any character or string will be dropped
+   --  if appended.
+private
+   type Bounded_String (Max_Length : Natural) is limited record
+      Length : Natural := 0;
+      --  Current length of the string
+
+      Chars  : String (1 .. Max_Length);
+      --  String content
+   end record;
+end System.Bounded_Strings;