--- a/gcc/streamer-hooks.h	Thu Oct 25 07:37:49 2018 +0900
+++ b/gcc/streamer-hooks.h	Thu Feb 13 11:34:05 2020 +0900
@@ -1,7 +1,7 @@
 /* Streamer hooks.  Support for adding streamer-specific callbacks to
    generic streaming routines.
 
-   Copyright (C) 2011-2018 Free Software Foundation, Inc.
+   Copyright (C) 2011-2020 Free Software Foundation, Inc.
    Contributed by Diego Novillo <dnovillo@google.com>
 
 This file is part of GCC.
@@ -25,8 +25,8 @@
 
 /* Forward declarations to avoid including unnecessary headers.  */
 struct output_block;
-struct lto_input_block;
-struct data_in;
+class lto_input_block;
+class data_in;
 
 /* Streamer hooks.  These functions do additional processing as
    needed by the module.  There are two types of callbacks, those that
@@ -49,10 +49,10 @@
      to the buffer where to read from and a data_in instance with tables
      and descriptors needed by the unpickling routines.  It returns the
      tree instantiated from the stream.  */
-  tree (*read_tree) (struct lto_input_block *, struct data_in *);
+  tree (*read_tree) (class lto_input_block *, class data_in *);
 
   /* [REQ] Called by every streaming routine that needs to read a location.  */
-  void (*input_location) (location_t *, struct bitpack_d *, struct data_in *);
+  void (*input_location) (location_t *, struct bitpack_d *, class data_in *);
 
   /* [REQ] Called by every streaming routine that needs to write a location.  */
   void (*output_location) (struct output_block *, struct bitpack_d *, location_t);