Langhooks fix and cleanup

[Neil Booth <neil at daikokuya dot demon dot co dot uk>]

This patch unconditionally defines the default langhooks; the
preprocessor conditions are superfluous clutter.  It also gives them
defaults that are non-NULL, like Mark requests for target hooks.

I have then updated toplev.c to remove checks for NULL, and updated
comments in toplev.h.

Finally, I have brought objc into the new regime, which it has managed
to duck so far.  Alexandre, I have a feeling that objc should be
sharing the inlining hooks of the C front end.  If so, you know that
much better than I, so would you take care of that?

Bootstrapped x86 Linux, making check.  OK to commit if successful?

Neil.

	* langhooks.c (lang_hook_default_do_nothing,
	lang_hook_default_decode_option): New defaults.
	* langhooks.h: Make hooks unconditional and non-NULL.
	* toplev.c (compile_file, toplev_main): Update.
	* toplev.h: Update comments.
	* ojbc/objc-act.c: Include langhooks.h.
	(lang_hooks): Initialize from macros.

Index: langhooks.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/langhooks.c,v
retrieving revision 1.3
diff -u -p -r1.3 langhooks.c
--- langhooks.c	2001/10/11 06:50:50	1.3
+++ langhooks.c	2001/10/19 22:58:59
@@ -29,6 +29,20 @@ Boston, MA 02111-1307, USA.  */
 #include "integrate.h"
 #include "langhooks.h"
 
+/* Do nothing; in many cases the default hook.  */
+void
+lang_hook_default_do_nothing ()
+{
+}
+
+/* Do nothing; the default hook to decode an option.  */
+int
+lang_hook_default_decode_option (argc, argv)
+     int argc ATTRIBUTE_UNUSED;
+     char **argv ATTRIBUTE_UNUSED;
+{
+  return 0;
+}
 
 /* lang_hooks.tree_inlining.walk_subtrees is called by walk_tree()
    after handling common cases, but before walking code-specific
Index: langhooks.h
===================================================================
RCS file: /cvs/gcc/gcc/gcc/langhooks.h,v
retrieving revision 1.1
diff -u -p -r1.1 langhooks.h
--- langhooks.h	2001/10/08 20:54:07	1.1
+++ langhooks.h	2001/10/19 22:58:59
@@ -22,23 +22,14 @@ Boston, MA 02111-1307, USA.  */
 #ifndef GCC_LANG_HOOKS_H
 #define GCC_LANG_HOOKS_H
 
-/* Older hooks, that don't go in sub-structures for backward
-   compatibility.  */
-#ifndef LANG_HOOKS_INIT
-#define LANG_HOOKS_INIT NULL
-#endif
-#ifndef LANG_HOOKS_FINISH
-#define LANG_HOOKS_FINISH NULL
-#endif
-#ifndef LANG_HOOKS_INIT_OPTIONS
-#define LANG_HOOKS_INIT_OPTIONS NULL
-#endif
-#ifndef LANG_HOOKS_DECODE_OPTION
-#define LANG_HOOKS_DECODE_OPTION NULL
-#endif
-#ifndef LANG_HOOKS_POST_OPTIONS
-#define LANG_HOOKS_POST_OPTIONS NULL
-#endif
+extern void lang_hook_default_do_nothing PARAMS ((void));
+extern int lang_hook_default_decode_option PARAMS ((int, char **));
+
+#define LANG_HOOKS_INIT			lang_hook_default_do_nothing
+#define LANG_HOOKS_FINISH		lang_hook_default_do_nothing
+#define LANG_HOOKS_INIT_OPTIONS		lang_hook_default_do_nothing
+#define LANG_HOOKS_DECODE_OPTION	lang_hook_default_decode_option
+#define LANG_HOOKS_POST_OPTIONS		lang_hook_default_do_nothing
 
 /* Declarations of default tree inlining hooks.  */
 tree tree_inlining_default_hook_walk_subtrees PARAMS ((tree*, int *,
Index: toplev.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/toplev.c,v
retrieving revision 1.521
diff -u -p -r1.521 toplev.c
--- toplev.c	2001/10/19 15:17:37	1.521
+++ toplev.c	2001/10/19 22:59:17
@@ -2221,8 +2221,7 @@ compile_file (name)
 
   /* Perform language-specific initialization.
      This may set main_input_filename.  */
-  if (lang_hooks.init)
-    (*lang_hooks.init) ();
+  (*lang_hooks.init) ();
 
   /* If the input doesn't start with a #line, use the input name
      as the official input file name.  */
@@ -2422,8 +2421,7 @@ compile_file (name)
 
   /* Language-specific end of compilation actions.  */
  finish_syntax:
-  if (lang_hooks.finish)
-    (*lang_hooks.finish) ();
+  (*lang_hooks.finish) ();
 
   /* Close the dump files.  */
 
@@ -4669,8 +4667,7 @@ toplev_main (argc, argv)
   add_params (lang_independent_params, LAST_PARAM);
 
   /* Perform language-specific options intialization.  */
-  if (lang_hooks.init_options)
-    (*lang_hooks.init_options) ();
+  (*lang_hooks.init_options) ();
 
   /* Scan to see what optimization level has been specified.  That will
      determine the default value of many flags.  */
@@ -4845,8 +4842,7 @@ toplev_main (argc, argv)
     }
 
   /* All command line options have been processed.  */
-  if (lang_hooks.post_options)
-    (*lang_hooks.post_options) ();
+  (*lang_hooks.post_options) ();
 
   if (exit_after_options)
     exit (0);
Index: toplev.h
===================================================================
RCS file: /cvs/gcc/gcc/gcc/toplev.h,v
retrieving revision 1.74
diff -u -p -r1.74 toplev.h
--- toplev.h	2001/10/08 20:54:07	1.74
+++ toplev.h	2001/10/19 22:59:32
@@ -138,7 +138,7 @@ struct lang_hooks_for_tree_inlining
   int (*anon_aggr_type_p) PARAMS ((union tree_node *));
 };
 
-/* Language-specific hooks.  Can be NULL unless otherwise specified.  */
+/* Language-specific hooks.  See langhooks.h for defaults.  */
 
 struct lang_hooks
 {
@@ -158,9 +158,7 @@ struct lang_hooks
      option.  If this function returns a negative number, then its
      absolute value is the number of command-line arguments used, but,
      in addition, no language-independent option processing should be
-     done for this option.
-
-     This hook cannot be NULL.  */
+     done for this option.  */
   int (*decode_option) PARAMS ((int, char **));
 
   /* Called when all command line options have been processed.  */
Index: objc/objc-act.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/objc/objc-act.c,v
retrieving revision 1.98
diff -u -p -r1.98 objc-act.c
--- objc-act.c	2001/10/12 16:01:16	1.98
+++ objc-act.c	2001/10/19 23:05:06
@@ -58,6 +58,7 @@ Boston, MA 02111-1307, USA.  */
 #include "cpplib.h"
 #include "debug.h"
 #include "target.h"
+#include "langhooks.h"
 
 /* This is the default way of generating a method name.  */
 /* I am not sure it is really correct.
@@ -449,12 +450,17 @@ static int generating_instance_variables
 
 static int print_struct_values = 0;
 
+#undef LANG_HOOKS_INIT
+#define LANG_HOOKS_INIT objc_init
+#undef LANG_HOOKS_INIT_OPTIONS
+#define LANG_HOOKS_INIT_OPTIONS objc_init_options
+#undef LANG_HOOKS_DECODE_OPTION
+#define LANG_HOOKS_DECODE_OPTION objc_decode_option
+#undef LANG_HOOKS_POST_OPTIONS
+#define LANG_HOOKS_POST_OPTIONS objc_post_options
+
 /* Each front end provides its own.  */
-struct lang_hooks lang_hooks = {objc_init,
-				NULL, /* objc_finish */
-				objc_init_options,
-				objc_decode_option,
-				objc_post_options};
+struct lang_hooks lang_hooks = LANG_HOOKS_INITIALIZER;
 
 /* Post-switch processing.  */
 static void