langhooks: preprocessor hooks for c++ modules

This is a slightly modified version of 01-langhooks.def.  I realized I
didn't need the deferred macro langhook -- that can be directly
installed into the preprocessor callbacks via preprocess_options lang
hook.

	gcc/
	* langhooks-def.h (LANG_HOOKS_PREPROCESS_MAIN_FILE)
	(LANG_HOOKS_PREPROCESS_OPTIONS, LANG_HOOKS_PREPROCESS_UNDEF)
	(LANG_HOOKS_PREPROCESS_TOKEN): New.
	(LANG_HOOKS_INITIALIZER): Add them.
	* langhooks.h (struct lang_hooks): Add preprocess_main_file,
	preprocess_options, preprocess_undef, preprocess_token hooks.  Add
	enum PT_flags.
	gcc/c-family/
	* c-lex.c: #include "langhooks.h".
	(cb_undef): Maybe call preprocess_undef lang hook.
	* c-opts.c (c_common_post_options): Maybe call preprocess_options
	lang hook.
	(push_command_line_include): Maybe call preprocess_main_file lang
	hook.
	(cb_file_change): Likewise.
	* c-ppoutput.c: #include "langhooks.h.
	(scan_translation_unit): Maybe call preprocess_token lang hook.
	(class do_streamer): New, derive from token_streamer.
	(directives_only_cb): Data pointer is do_streamer, call
	preprocess_token lang hook.
	(scan_translation_unit_directives_only): Use do_streamer.
	(print_line_1): Move src_line recording to after string output.
	(cb_undef): Maybe call preprocess_undef lang hook.

1 files changed, 18 insertions, 0 deletions

diff --git a/gcc/langhooks.h b/gcc/langhooks.h
index a35cf21..f12589e 100644
--- a/gcc/langhooks.h
+++ b/gcc/langhooks.h
@@ -356,6 +356,24 @@ struct lang_hooks
      global diagnostic context structure.  */
   void (*initialize_diagnostics) (diagnostic_context *);
 
+  /* Beginning the main source file.  */
+  void (*preprocess_main_file) (cpp_reader *, line_maps *,
+				const line_map_ordinary *);
+
+  /* Adjust libcpp options and callbacks.  */
+  void (*preprocess_options) (cpp_reader *);
+
+  /* Undefining a macro.  */
+  void (*preprocess_undef) (cpp_reader *, location_t, cpp_hashnode *);
+
+  /* Observer for preprocessing stream.  */
+  uintptr_t (*preprocess_token) (cpp_reader *, const cpp_token *, uintptr_t);
+  /* Various flags it can return about the token.  */
+  enum PT_flags
+    {
+     PT_begin_pragma = 1 << 0
+    };
+
   /* Register language-specific dumps.  */
   void (*register_dumps) (gcc::dump_manager *);