Index: libcpp/line-map.c
===================================================================
--- libcpp/line-map.c	(revision 190209)
+++ libcpp/line-map.c	(working copy)
@@ -25,6 +25,7 @@
 #include "line-map.h"
 #include "cpplib.h"
 #include "internal.h"
+#include "hashtab.h"

 static void trace_include (const struct line_maps *, const struct line_map *);
 static const struct line_map * linemap_ordinary_map_lookup (struct line_maps *,
@@ -50,6 +51,135 @@
 extern unsigned num_expanded_macros_counter;
 extern unsigned num_macro_tokens_counter;

+/* Data structure to associate an arbitrary data to a source location.  */
+struct location_adhoc_data {
+  source_location locus;
+  void *data;
+};
+
+/* The following data structure encodes a location with some adhoc data
+   and maps it to a new unsigned integer (called an adhoc location)
+   that replaces the original location to represent the mapping.
+
+   The new adhoc_loc uses the highest bit as the enabling bit, i.e. if the
+   highest bit is 1, then the number is adhoc_loc. Otherwise, it serves as
+   the original location. Once identified as the adhoc_loc, the lower 31
+   bits of the integer is used to index the location_adhoc_data array,
+   in which the locus and associated data is stored.  */
+
+static htab_t location_adhoc_data_htab;
+static source_location curr_adhoc_loc;
+static struct location_adhoc_data *location_adhoc_data;
+static unsigned int allocated_location_adhoc_data;
+
+/* Hash function for location_adhoc_data hashtable.  */
+
+static hashval_t
+location_adhoc_data_hash (const void *l)
+{
+  const struct location_adhoc_data *lb =
+      (const struct location_adhoc_data *) l;
+  return (hashval_t) lb->locus + (size_t) &lb->data;
+}
+
+/* Compare function for location_adhoc_data hashtable.  */
+
+static int
+location_adhoc_data_eq (const void *l1, const void *l2)
+{
+  const struct location_adhoc_data *lb1 =
+      (const struct location_adhoc_data *) l1;
+  const struct location_adhoc_data *lb2 =
+      (const struct location_adhoc_data *) l2;
+  return lb1->locus == lb2->locus && lb1->data == lb2->data;
+}
+
+/* Update the hashtable when location_adhoc_data is reallocated.  */
+
+static int
+location_adhoc_data_update (void **slot, void *data)
+{
+  *((char **) slot) += ((char *) location_adhoc_data - (char *) data);
+  return 1;
+}
+
+/* Combine LOCUS and DATA to a combined adhoc loc.  */
+
+source_location
+get_combined_adhoc_loc (source_location locus, void *data)
+{
+  struct location_adhoc_data lb;
+  struct location_adhoc_data **slot;
+
+  linemap_assert (data);
+
+  if (IS_ADHOC_LOC (locus))
+    locus = location_adhoc_data[locus & MAX_SOURCE_LOCATION].locus;
+  if (locus == 0 && data == NULL)
+    return 0;
+  lb.locus = locus;
+  lb.data = data;
+  slot = (struct location_adhoc_data **)
+      htab_find_slot (location_adhoc_data_htab, &lb, INSERT);
+  if (*slot == NULL)
+    {
+      *slot = location_adhoc_data + curr_adhoc_loc;
+      location_adhoc_data[curr_adhoc_loc] = lb;
+      if (++curr_adhoc_loc >= allocated_location_adhoc_data)
+	{
+	  char *orig_location_adhoc_data = (char *) location_adhoc_data;
+	  allocated_location_adhoc_data *= 2;
+	  location_adhoc_data = XRESIZEVEC (struct location_adhoc_data,
+					    location_adhoc_data,
+					    allocated_location_adhoc_data);
+	  htab_traverse (location_adhoc_data_htab, location_adhoc_data_update,
+			 orig_location_adhoc_data);
+	}
+    }
+  return ((*slot) - location_adhoc_data) | 0x80000000;
+}
+
+/* Return the data for the adhoc loc.  */
+
+void *
+get_data_from_adhoc_loc (source_location loc)
+{
+  linemap_assert (IS_ADHOC_LOC (loc));
+  return location_adhoc_data[loc & MAX_SOURCE_LOCATION].data;
+}
+
+/* Return the location for the adhoc loc.  */
+
+source_location
+get_location_from_adhoc_loc (source_location loc)
+{
+  linemap_assert (IS_ADHOC_LOC (loc));
+  return location_adhoc_data[loc & MAX_SOURCE_LOCATION].locus;
+}
+
+/* Initialize the location_adhoc_data structure.  */
+
+void
+location_adhoc_data_init (void)
+{
+  location_adhoc_data_htab = htab_create (100, location_adhoc_data_hash,
+					  location_adhoc_data_eq, NULL);
+  curr_adhoc_loc = 0;
+  allocated_location_adhoc_data = 100;
+  location_adhoc_data = XNEWVEC (struct location_adhoc_data,
+				 allocated_location_adhoc_data);
+}
+
+/* Finalize the location_adhoc_data structure.  */
+
+void
+location_adhoc_data_fini (void)
+{
+  allocated_location_adhoc_data = 0;
+  XDELETEVEC (location_adhoc_data);
+  htab_delete (location_adhoc_data_htab);
+}
+
 /* Initialize a line map set.  */

 void
@@ -509,6 +639,8 @@
 const struct line_map*
 linemap_lookup (struct line_maps *set, source_location line)
 {
+  if (IS_ADHOC_LOC (line))
+    line = location_adhoc_data[line & MAX_SOURCE_LOCATION].locus;
   if (linemap_location_from_macro_expansion_p (set, line))
     return linemap_macro_map_lookup (set, line);
   return linemap_ordinary_map_lookup (set, line);
@@ -525,6 +657,9 @@
   unsigned int md, mn, mx;
   const struct line_map *cached, *result;

+  if (IS_ADHOC_LOC (line))
+    line = location_adhoc_data[line & MAX_SOURCE_LOCATION].locus;
+
   if (set ==  NULL || line < RESERVED_LOCATION_COUNT)
     return NULL;

@@ -570,6 +705,9 @@
   unsigned int md, mn, mx;
   const struct line_map *cached, *result;

+  if (IS_ADHOC_LOC (line))
+    line = location_adhoc_data[line & MAX_SOURCE_LOCATION].locus;
+
   linemap_assert (line >= LINEMAPS_MACRO_LOWEST_LOCATION (set));

   if (set ==  NULL)
@@ -648,6 +786,9 @@
 {
   unsigned token_no;

+  if (IS_ADHOC_LOC (location))
+    location = location_adhoc_data[location & MAX_SOURCE_LOCATION].locus;
+
   linemap_assert (linemap_macro_expansion_map_p (map)
 		  && location >= MAP_START_LOCATION (map));
   linemap_assert (location >= RESERVED_LOCATION_COUNT);
@@ -672,6 +813,9 @@
 {
   unsigned token_no;

+  if (IS_ADHOC_LOC (location))
+    location = location_adhoc_data[location & MAX_SOURCE_LOCATION].locus;
+
   linemap_assert (linemap_macro_expansion_map_p (map)
 		  && location >= MAP_START_LOCATION (map));
   linemap_assert (location >= RESERVED_LOCATION_COUNT);
@@ -696,6 +840,9 @@
 {
   const struct line_map *map = NULL;

+  if (IS_ADHOC_LOC (location))
+    location = location_adhoc_data[location & MAX_SOURCE_LOCATION].locus;
+
   if (location < RESERVED_LOCATION_COUNT)
     return 0;

@@ -720,6 +867,9 @@
 {
   const struct line_map *map = NULL;

+  if (IS_ADHOC_LOC (location))
+    location = location_adhoc_data[location & MAX_SOURCE_LOCATION].locus;
+
   if (location < RESERVED_LOCATION_COUNT)
     return NULL;

@@ -754,6 +904,9 @@
 {
   const struct line_map *map = NULL;

+  if (IS_ADHOC_LOC (location))
+    location = location_adhoc_data[location & MAX_SOURCE_LOCATION].locus;
+
   if (location < RESERVED_LOCATION_COUNT)
     return false;

@@ -793,6 +946,9 @@
 linemap_location_from_macro_expansion_p (struct line_maps *set,
 					 source_location location)
 {
+  if (IS_ADHOC_LOC (location))
+    location = location_adhoc_data[location & MAX_SOURCE_LOCATION].locus;
+
   linemap_assert (location <= MAX_SOURCE_LOCATION
 		  && (set->highest_location
 		      < LINEMAPS_MACRO_LOWEST_LOCATION (set)));
@@ -933,6 +1089,9 @@
 {
   struct line_map *map;

+  if (IS_ADHOC_LOC (location))
+    location = location_adhoc_data[location & MAX_SOURCE_LOCATION].locus;
+
   linemap_assert (set && location >= RESERVED_LOCATION_COUNT);

   while (true)
@@ -967,6 +1126,9 @@
 {
   struct line_map *map;

+  if (IS_ADHOC_LOC (location))
+    location = location_adhoc_data[location & MAX_SOURCE_LOCATION].locus;
+
   linemap_assert (set && location >= RESERVED_LOCATION_COUNT);

   while (true)
@@ -1005,6 +1167,9 @@
 {
   struct line_map *map;

+  if (IS_ADHOC_LOC (location))
+    location = location_adhoc_data[location & MAX_SOURCE_LOCATION].locus;
+
   linemap_assert (set && location >= RESERVED_LOCATION_COUNT);

   while (true)
@@ -1074,6 +1239,9 @@
 			  enum location_resolution_kind lrk,
 			  const struct line_map **map)
 {
+  if (IS_ADHOC_LOC (loc))
+    loc = location_adhoc_data[loc & MAX_SOURCE_LOCATION].locus;
+
   if (loc < RESERVED_LOCATION_COUNT)
     {
       /* A reserved location wasn't encoded in a map.  Let's return a
@@ -1121,6 +1289,9 @@
   source_location resolved_location;
   const struct line_map *resolved_map;

+  if (IS_ADHOC_LOC (loc))
+    loc = location_adhoc_data[loc & MAX_SOURCE_LOCATION].locus;
+
   resolved_location =
     linemap_macro_map_loc_unwind_toward_spelling (*map, loc);
   resolved_map = linemap_lookup (set, resolved_location);
@@ -1157,6 +1328,9 @@
   source_location resolved_loc;
   const struct line_map *map0 = NULL, *map1 = NULL;

+  if (IS_ADHOC_LOC (loc))
+    loc = location_adhoc_data[loc & MAX_SOURCE_LOCATION].locus;
+
   map0 = linemap_lookup (set, loc);
   if (!linemap_macro_expansion_map_p (map0))
     return loc;
@@ -1198,6 +1372,11 @@
   expanded_location xloc;

   memset (&xloc, 0, sizeof (xloc));
+  if (IS_ADHOC_LOC (loc))
+    {
+      loc = location_adhoc_data[loc & MAX_SOURCE_LOCATION].locus;
+      xloc.data = location_adhoc_data[loc & MAX_SOURCE_LOCATION].data;
+    }

   if (loc < RESERVED_LOCATION_COUNT)
     /* The location for this token wasn't generated from a line map.
@@ -1290,6 +1469,9 @@
   const char *path = "", *from = "";
   int l = -1, c = -1, s = -1, e = -1;

+  if (IS_ADHOC_LOC (loc))
+    loc = location_adhoc_data[loc & MAX_SOURCE_LOCATION].locus;
+
   if (loc == 0)
     return;

