1 files changed, 44 insertions, 0 deletions
diff --git a/libcpp/line-map.c b/libcpp/line-map.c
index d10d578f62e0..aff0294936c3 100644
--- a/libcpp/line-map.c
+++ b/libcpp/line-map.c
@@ -633,6 +633,50 @@ linemap_position_for_line_and_column (const struct line_map *map,
 	  + (column & ((1 << ORDINARY_MAP_NUMBER_OF_COLUMN_BITS (map)) - 1)));
 }
 
+/* Encode and return a source_location starting from location LOC and
+   shifting it by OFFSET columns.  This function does not support
+   virtual locations.  */
+
+source_location
+linemap_position_for_loc_and_offset (struct line_maps *set,
+				     source_location loc,
+				     unsigned int offset)
+{
+  const struct line_map * map = NULL;
+
+  /* This function does not support virtual locations yet.  */
+  linemap_assert (!linemap_location_from_macro_expansion_p (set, loc));
+
+  if (offset == 0
+      /* Adding an offset to a reserved location (like
+	 UNKNOWN_LOCATION for the C/C++ FEs) does not really make
+	 sense.  So let's leave the location intact in that case.  */
+      || loc < RESERVED_LOCATION_COUNT)
+    return loc;
+
+  /* We find the real location and shift it.  */
+  loc = linemap_resolve_location (set, loc, LRK_SPELLING_LOCATION, &map);
+  /* The new location (loc + offset) should be higher than the first
+     location encoded by MAP.  */
+  linemap_assert (MAP_START_LOCATION (map) < loc + offset);
+
+  /* If MAP is not the last line map of its set, then the new location
+     (loc + offset) should be less than the first location encoded by
+     the next line map of the set.  */
+  if (map != LINEMAPS_LAST_ORDINARY_MAP (set))
+    linemap_assert (loc + offset < MAP_START_LOCATION (&map[1]));
+
+  offset += SOURCE_COLUMN (map, loc);
+  linemap_assert (offset < (1u << map->d.ordinary.column_bits));
+
+  source_location r = 
+    linemap_position_for_line_and_column (map,
+					  SOURCE_LINE (map, loc),
+					  offset);
+  linemap_assert (map == linemap_lookup (set, r));
+  return r;
+}
+
 /* Given a virtual source location yielded by a map (either an
    ordinary or a macro map), returns that map.  */