cpplib: Macro use location and comparison

Our macro use hook passes a location, but doesn't recieve it from the
using location.  This patch adds the extra location_t parameter and
passes it though.

A second cleanup is breaking out the macro comparison code from the
redefinition warning.  That;ll turn out useful for modules.

Finally, there's a filename comparison needed for the location
optimization of rewinding from line 2 (occurs during the emission of
builtin macros).

	libcpp/
	* internal.h (_cpp_notify_macro_use): Add location parm.
	(_cpp_maybe_notify_macro_use): Likewise.
	* directives.c (_cpp_do_file_change): Check we've not changed file
	when optimizing a rewind.
	(do_ifdef): Pass location to _cpp_maybe_notify_macro_use.
	(do_ifndef): Likewise.  Delete obsolete comment about powerpc.
	* expr.c (parse_defined): Pass location to
	_cpp_maybe_notify_macro_use.
	* macro.c (enter_macro_context): Likewise.
	(warn_of_redefinition): Break out helper function.  Call it.
	(compare_macros): New function broken out of warn_of_redefinition.
	(_cpp_new_macro): Zero all fields.
	(_cpp_notify_macro_use): Add location parameter.

libcpp/directives.c

@@ -1134,6 +1134,7 @@ _cpp_do_file_change (cpp_reader *pfile, enum lc_reason reason,
          preprocessed source.  */
       line_map_ordinary *last = LINEMAPS_LAST_ORDINARY_MAP (pfile->line_table);
       if (!ORDINARY_MAP_STARTING_LINE_NUMBER (last)
+	  && 0 == filename_cmp (to_file, ORDINARY_MAP_FILE_NAME (last))
 	  && SOURCE_LINE (last, pfile->line_table->highest_line) == 2)
 	{
 	  ord_map = last;
@@ -1981,7 +1982,7 @@ do_ifdef (cpp_reader *pfile)
 	{
 	  skip = !_cpp_defined_macro_p (node);
 	  _cpp_mark_macro_used (node);
-	  _cpp_maybe_notify_macro_use (pfile, node);
+	  _cpp_maybe_notify_macro_use (pfile, node, pfile->directive_line);
 	  if (pfile->cb.used)
 	    pfile->cb.used (pfile, pfile->directive_line, node);
 	  check_eol (pfile, false);
@@ -2004,13 +2005,9 @@ do_ifndef (cpp_reader *pfile)
 
       if (node)
 	{
-	  /* Do not treat conditional macros as being defined.  This is due to
-	     the powerpc port using conditional macros for 'vector', 'bool',
-	     and 'pixel' to act as conditional keywords.  This messes up tests
-	     like #ifndef bool.  */
 	  skip = _cpp_defined_macro_p (node);
 	  _cpp_mark_macro_used (node);
-	  _cpp_maybe_notify_macro_use (pfile, node);
+	  _cpp_maybe_notify_macro_use (pfile, node, pfile->directive_line);
 	  if (pfile->cb.used)
 	    pfile->cb.used (pfile, pfile->directive_line, node);
 	  check_eol (pfile, false);

libcpp/expr.c

@@ -1070,7 +1070,7 @@ parse_defined (cpp_reader *pfile)
 		        "this use of \"defined\" may not be portable");
 
       _cpp_mark_macro_used (node);
-      _cpp_maybe_notify_macro_use (pfile, node);
+      _cpp_maybe_notify_macro_use (pfile, node, token->src_loc);
 
       /* A possible controlling macro of the form #if !defined ().
 	 _cpp_parse_expr checks there was no other junk on the line.  */

libcpp/internal.h

@@ -649,11 +649,13 @@ inline bool _cpp_defined_macro_p (cpp_hashnode *node)
 }
 
 /* In macro.c */
-extern void _cpp_notify_macro_use (cpp_reader *pfile, cpp_hashnode *node);
-inline void _cpp_maybe_notify_macro_use (cpp_reader *pfile, cpp_hashnode *node)
+extern void _cpp_notify_macro_use (cpp_reader *pfile, cpp_hashnode *node,
+				   location_t loc);
+inline void _cpp_maybe_notify_macro_use (cpp_reader *pfile, cpp_hashnode *node,
+					 location_t loc)
 {
   if (!(node->flags & NODE_USED))
-    _cpp_notify_macro_use (pfile, node);
+    _cpp_notify_macro_use (pfile, node, loc);
 }
 extern cpp_macro *_cpp_new_macro (cpp_reader *, cpp_macro_kind, void *);
 extern void _cpp_free_definition (cpp_hashnode *);

libcpp/macro.c

@@ -340,6 +340,8 @@ static cpp_macro *create_iso_definition (cpp_reader *);
 static cpp_macro *lex_expansion_token (cpp_reader *, cpp_macro *);
 static bool warn_of_redefinition (cpp_reader *, cpp_hashnode *,
 				  const cpp_macro *);
+static bool compare_macros (const cpp_macro *, const cpp_macro *);
+
 static bool parse_params (cpp_reader *, unsigned *, bool *);
 static void check_trad_stringification (cpp_reader *, const cpp_macro *,
 					const cpp_string *);
@@ -1433,7 +1435,7 @@ enter_macro_context (cpp_reader *pfile, cpp_hashnode *node,
 
       /* Laziness can only affect the expansion tokens of the macro,
 	 not its fun-likeness or parameters.  */
-      _cpp_maybe_notify_macro_use (pfile, node);
+      _cpp_maybe_notify_macro_use (pfile, node, location);
       if (pfile->cb.used)
 	pfile->cb.used (pfile, location, node);
 
@@ -3111,6 +3113,14 @@ warn_of_redefinition (cpp_reader *pfile, cpp_hashnode *node,
       macro1->lazy = 0;
     }
 
+  return compare_macros (macro1, macro2);
+}
+
+/* Return TRUE if MACRO1 and MACRO2 differ.  */
+
+static bool
+compare_macros (const cpp_macro *macro1, const cpp_macro *macro2)
+{
   /* Redefinition of a macro is allowed if and only if the old and new
      definitions are the same.  (6.10.3 paragraph 2).  */
 
@@ -3579,6 +3589,10 @@ _cpp_new_macro (cpp_reader *pfile, cpp_macro_kind kind, void *placement)
 {
   cpp_macro *macro = (cpp_macro *) placement;
 
+  /* Zero init all the fields.  This'll tell the compiler know all the
+     following inits are writing a virgin object.  */
+  memset (macro, 0, offsetof (cpp_macro, exp));
+
   macro->line = pfile->directive_line;
   macro->parm.params = 0;
   macro->lazy = 0;
@@ -3665,10 +3679,12 @@ cpp_define_lazily (cpp_reader *pfile, cpp_hashnode *node, unsigned num)
 }
 
 /* Notify the use of NODE in a macro-aware context (i.e. expanding it,
-   or testing its existance).  Also applies any lazy definition.  */
+   or testing its existance).  Also applies any lazy definition.
+   Return FALSE if the macro isn't really there.  */
 
 extern void
-_cpp_notify_macro_use (cpp_reader *pfile, cpp_hashnode *node)
+_cpp_notify_macro_use (cpp_reader *pfile, cpp_hashnode *node,
+		       location_t loc)
 {
   node->flags |= NODE_USED;
   switch (node->type)
@@ -3686,12 +3702,12 @@ _cpp_notify_macro_use (cpp_reader *pfile, cpp_hashnode *node)
 
     case NT_BUILTIN_MACRO:
       if (pfile->cb.used_define)
-	pfile->cb.used_define (pfile, pfile->directive_line, node);
+	pfile->cb.used_define (pfile, loc, node);
       break;
 
     case NT_VOID:
       if (pfile->cb.used_undef)
-	pfile->cb.used_undef (pfile, pfile->directive_line, node);
+	pfile->cb.used_undef (pfile, loc, node);
       break;
 
     default: