--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gcc/streamer-hooks.h	Fri Oct 27 22:46:09 2017 +0900
@@ -0,0 +1,82 @@
+/* Streamer hooks.  Support for adding streamer-specific callbacks to
+   generic streaming routines.
+
+   Copyright (C) 2011-2017 Free Software Foundation, Inc.
+   Contributed by Diego Novillo <dnovillo@google.com>
+
+This file is part of GCC.
+
+GCC is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation; either version 3, or (at your option) any later
+version.
+
+GCC is distributed in the hope that it will be useful, but WITHOUT 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
+along with GCC; see the file COPYING3.  If not see
+<http://www.gnu.org/licenses/>.  */
+
+#ifndef GCC_STREAMER_HOOKS_H
+#define GCC_STREAMER_HOOKS_H
+
+/* Forward declarations to avoid including unnecessary headers.  */
+struct output_block;
+struct lto_input_block;
+struct data_in;
+
+/* Streamer hooks.  These functions do additional processing as
+   needed by the module.  There are two types of callbacks, those that
+   replace the default behavior and those that supplement it.
+
+   Hooks marked [REQ] are required to be set.  Those marked [OPT] may
+   be NULL, if the streamer does not need to implement them.  */
+struct streamer_hooks {
+  /* [REQ] Called by every tree streaming routine that needs to write
+     a tree node.  The arguments are: output_block where to write the
+     node, the tree node to write and a boolean flag that should be true
+     if the caller wants to write a reference to the tree, instead of the
+     tree itself.  The second boolean parameter specifies this for
+     the tree itself, the first for all siblings that are streamed.
+     The referencing mechanism is up to each streamer to implement.  */
+  void (*write_tree) (struct output_block *, tree, bool, bool);
+
+  /* [REQ] Called by every tree streaming routine that needs to read
+     a tree node.  It takes two arguments: an lto_input_block pointing
+     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 *);
+
+  /* [REQ] Called by every streaming routine that needs to read a location.  */
+  void (*input_location) (location_t *, struct bitpack_d *, struct 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);
+};
+
+#define stream_write_tree(OB, EXPR, REF_P) \
+    streamer_hooks.write_tree (OB, EXPR, REF_P, REF_P)
+
+#define stream_write_tree_shallow_non_ref(OB, EXPR, REF_P) \
+    streamer_hooks.write_tree (OB, EXPR, REF_P, false)
+
+#define stream_read_tree(IB, DATA_IN) \
+    streamer_hooks.read_tree (IB, DATA_IN)
+
+#define stream_input_location(LOCPTR, BP, DATA_IN) \
+    streamer_hooks.input_location (LOCPTR, BP, DATA_IN)
+
+#define stream_output_location(OB, BP, LOC) \
+    streamer_hooks.output_location (OB, BP, LOC)
+
+/* Streamer hooks.  */
+extern struct streamer_hooks streamer_hooks;
+
+/* In streamer-hooks.c.  */
+void streamer_hooks_init (void);
+
+#endif  /* GCC_STREAMER_HOOKS_H  */