cleanups in line-map

Index: libcpp/include/line-map.h
===================================================================
--- libcpp/include/line-map.h	(revision 216098)
+++ libcpp/include/line-map.h	(working copy)
@@ -521,11 +521,11 @@  int linemap_location_in_system_header_p
 					 source_location);
 
 /* Return TRUE if LOCATION is a source code location of a token coming
    from a macro replacement-list at a macro expansion point, FALSE
    otherwise.  */
-bool linemap_location_from_macro_expansion_p (struct line_maps *,
+bool linemap_location_from_macro_expansion_p (const struct line_maps *,
 					      source_location);
 
 /* source_location values from 0 to RESERVED_LOCATION_COUNT-1 will
    be reserved for libcpp user as special values, no token from libcpp
    will contain any of those locations.  */
@@ -597,13 +597,14 @@  bool linemap_location_from_macro_expansi
 extern source_location
 linemap_position_for_column (struct line_maps *, unsigned int);
 
 /* Encode and return a source location from a given line and
    column.  */
-source_location linemap_position_for_line_and_column (struct line_map *,
-						      linenum_type,
-						      unsigned int);
+source_location
+linemap_position_for_line_and_column (const struct line_map *,
+				      linenum_type, unsigned int);
+
 /* Return the file this map is for.  */
 #define LINEMAP_FILE(MAP)					\
   (linemap_check_ordinary (MAP)->d.ordinary.to_file)
 
 /* Return the line number this map started encoding location from.  */
Index: libcpp/line-map.c
===================================================================
--- libcpp/line-map.c	(revision 216098)
+++ libcpp/line-map.c	(working copy)
@@ -29,12 +29,10 @@  along with this program; see the file CO
 static void trace_include (const struct line_maps *, const struct line_map *);
 static const struct line_map * linemap_ordinary_map_lookup (struct line_maps *,
 							    source_location);
 static const struct line_map* linemap_macro_map_lookup (struct line_maps *,
 							source_location);
-static source_location linemap_macro_map_loc_to_def_point
-(const struct line_map*, source_location);
 static source_location linemap_macro_map_loc_unwind_toward_spelling
 (const struct line_map*, source_location);
 static source_location linemap_macro_map_loc_to_exp_point
 (const struct line_map*, source_location);
 static source_location linemap_macro_loc_to_spelling_point
@@ -482,11 +480,11 @@  linemap_enter_macro (struct line_maps *s
    definition, it is the locus in the macro definition; otherwise it
    is a location in the context of the caller of this macro expansion
    (which is a virtual location or a source location if the caller is
    itself a macro expansion or not).
 
-   MACRO_DEFINITION_LOC is the location in the macro definition,
+   ORIG_PARM_REPLACEMENT_LOC is the location in the macro definition,
    either of the token itself or of a macro parameter that it
    replaces.  */
 
 source_location
 linemap_add_macro_token (const struct line_map *map,
@@ -619,11 +617,11 @@  linemap_position_for_column (struct line
 
 /* Encode and return a source location from a given line and
    column.  */
 
 source_location
-linemap_position_for_line_and_column (struct line_map *map,
+linemap_position_for_line_and_column (const struct line_map *map,
 				      linenum_type line,
 				      unsigned column)
 {
   linemap_assert (ORDINARY_MAP_STARTING_LINE_NUMBER (map) <= line);
 
@@ -770,19 +768,17 @@  linemap_macro_map_loc_to_exp_point (cons
 		  <  MACRO_MAP_NUM_MACRO_TOKENS (map));
 
   return MACRO_MAP_EXPANSION_POINT_LOCATION (map);
 }
 
-/* If LOCATION is the source location of a token that belongs to a
-   macro replacement-list -- as part of a macro expansion -- then
-   return the location of the token at the definition point of the
-   macro.  Otherwise, return LOCATION.  SET is the set of maps
-   location come from.  ORIGINAL_MAP is an output parm. If non NULL,
-   the function sets *ORIGINAL_MAP to the ordinary (non-macro) map the
-   returned location comes from.  */
+/* LOCATION is the source location of a token that belongs to a macro
+   replacement-list as part of the macro expansion denoted by MAP.
 
-source_location
+   Return the location of the token at the definition point of the
+   macro.  */
+
+static source_location
 linemap_macro_map_loc_to_def_point (const struct line_map *map,
 				    source_location location)
 {
   unsigned token_no;
 
@@ -938,11 +934,11 @@  linemap_location_in_system_header_p (str
 /* Return TRUE if LOCATION is a source code location of a token coming
    from a macro replacement-list at a macro expansion point, FALSE
    otherwise.  */
 
 bool
-linemap_location_from_macro_expansion_p (struct line_maps *set,
+linemap_location_from_macro_expansion_p (const struct line_maps *set,
 					 source_location location)
 {
   if (IS_ADHOC_LOC (location))
     location = set->location_adhoc_data_map.data[location
 						 & MAX_SOURCE_LOCATION].locus;
@@ -1231,13 +1227,13 @@  linemap_macro_loc_to_exp_point (struct l
 
    If LOC is the locus of a token that is not an argument of a
    function-like macro, then the function behaves as if LRK was set to
    LRK_SPELLING_LOCATION.
 
-   If LOC_MAP is not NULL, *LOC_MAP is set to the map encoding the
+   If MAP is not NULL, *MAP is set to the map encoding the
    returned location.  Note that if the returned location wasn't originally
-   encoded by a map, the *MAP is set to NULL.  This can happen if LOC
+   encoded by a map, then *MAP is set to NULL.  This can happen if LOC
    resolves to a location reserved for the client code, like
    UNKNOWN_LOCATION or BUILTINS_LOCATION in GCC.  */
 
 source_location
 linemap_resolve_location (struct line_maps *set,