Linemap infrastructure for virtual locations

This is the first instalment of a set which goal is to track locations
of tokens across macro expansions.  Tom Tromey did the original work
and attached the patch to PR preprocessor/7263.  This opus is a
derivative of that original work.

This patch modifies the linemap module of libcpp to add virtual
locations support.

A virtual location is a mapped location that can resolve to several
different physical locations.  It can always resolve to the spelling
location of a token.  For tokens resulting from macro expansion it can
resolve to:
  - either the location of the expansion point of the macro.
  - or the location of the token in the definition of the
  macro
  - or, if the token is an argument of a function-like macro,
  the location of the use of the matching macro parameter in
  the definition of the macro

The patch creates a new type of line map called a macro map.  For every
single macro expansion, there is a macro map that generates a virtual
location for every single resulting token of the expansion.

The good old type of line map we all know is now called an ordinary
map.  That one still encodes spelling locations as it has always had.

As a result linemap_lookup as been extended to return a macro map when
given a virtual location resulting from a macro expansion.  The layout
of structs line_map has changed to support this new type of map.  So
did the layout of struct line_maps.  Accessor macros have been
introduced to avoid messing with the implementation details of these
datastructures directly.  This helped already as we have been testing
different ways of arranging these datastructure.  Having to constantly
adjust client code that is too tied with the internals of line_map and
line_maps would have been even more painful.

Of course, many new public functions have been added to the linemap
module to handle the resolution of virtual locations.

This patch introduces the infrastructure but no part of the compiler
uses virtual locations yet.

However the client code of the linemap data structures has been
adjusted as per the changes.  E.g, it's not anymore reliable for a
client code to manipulate struct line_map directly if it just wants to
deal with spelling locations, because struct line_map can now
represent a macro map as well.  In that case, it's better to use the
convenient API to resolve the initial (possibly virtual) location to a
spelling location (or to an ordinary map) and use that.

This is the reason why the patch adjusts the Java, Ada and Fortran
front ends.

Also, note that virtual locations are not supposed to be ordered for
relations '<' and '>' anymore.  To test if a virtual location appears
"before" another one, one has to use a new operator exposed by the
line map interface.  The patch updates the only spot (in the
diagnostics module) I have found that was making the assumption that
locations were ordered for these relations.  This is the only change
that introduces a use of the new line map API in this patch, so I am
adding a regression test for it only.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@180081 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 868 insertions, 78 deletions

diff --git a/libcpp/line-map.c b/libcpp/line-map.c
index 2a0749aad2e..49de2449be9 100644
--- a/libcpp/line-map.c
+++ b/libcpp/line-map.c
@@ -23,24 +23,37 @@ along with this program; see the file COPYING3.  If not see
 #include "config.h"
 #include "system.h"
 #include "line-map.h"
+#include "cpplib.h"
+#include "internal.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 *,
+							    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
+(struct line_maps *, source_location, const struct line_map **);
+static source_location linemap_macro_loc_to_def_point (struct line_maps *,
+						       source_location,
+						       const struct line_map **);
+static source_location linemap_macro_loc_to_exp_point (struct line_maps *,
+						       source_location,
+						       const struct line_map **);
 
 /* Initialize a line map set.  */
 
 void
 linemap_init (struct line_maps *set)
 {
-  set->maps = NULL;
-  set->allocated = 0;
-  set->used = 0;
-  set->trace_includes = false;
-  set->depth = 0;
-  set->cache = 0;
+  memset (set, 0, sizeof (struct line_maps));
   set->highest_location = RESERVED_LOCATION_COUNT - 1;
   set->highest_line = RESERVED_LOCATION_COUNT - 1;
-  set->max_column_hint = 0;
-  set->reallocator = 0;
 }
 
 /* Check for and warn about line_maps entered but not exited.  */
@@ -51,23 +64,55 @@ linemap_check_files_exited (struct line_maps *set)
   struct line_map *map;
   /* Depending upon whether we are handling preprocessed input or
      not, this can be a user error or an ICE.  */
-  for (map = &set->maps[set->used - 1]; ! MAIN_FILE_P (map);
+  for (map = LINEMAPS_LAST_ORDINARY_MAP (set);
+       ! MAIN_FILE_P (map);
        map = INCLUDED_FROM (set, map))
     fprintf (stderr, "line-map.c: file \"%s\" entered but not left\n",
-	     map->to_file);
+	     ORDINARY_MAP_FILE_NAME (map));
 }
- 
-/* Free a line map set.  */
 
-void
-linemap_free (struct line_maps *set)
+/* Create a new line map in the line map set SET, and return it.
+   REASON is the reason of creating the map. It determines the type
+   of map created (ordinary or macro map). Note that ordinary maps and
+   macro maps are allocated in different memory location.  */
+
+static struct line_map *
+new_linemap (struct line_maps *set,
+	     enum lc_reason reason)
 {
-  if (set->maps)
+  /* Depending on this variable, a macro map would be allocated in a
+     different memory location than an ordinary map.  */
+  bool macro_map_p = (reason == LC_ENTER_MACRO);
+  struct line_map *result;
+
+  if (LINEMAPS_USED (set, macro_map_p) == LINEMAPS_ALLOCATED (set, macro_map_p))
     {
-      linemap_check_files_exited (set);
+      /* We ran out of allocated line maps. Let's allocate more.  */
 
-      free (set->maps);
+      line_map_realloc reallocator
+	= set->reallocator ? set->reallocator : xrealloc;
+      LINEMAPS_ALLOCATED (set, macro_map_p) =
+	2 * LINEMAPS_ALLOCATED (set, macro_map_p) + 256;
+      LINEMAPS_MAPS (set, macro_map_p)
+	= (struct line_map *) (*reallocator) (LINEMAPS_MAPS (set, macro_map_p),
+					      LINEMAPS_ALLOCATED (set,
+								  macro_map_p)
+					      * sizeof (struct line_map));
+      result =
+	&LINEMAPS_MAPS (set, macro_map_p)[LINEMAPS_USED (set, macro_map_p)];
+      memset (result, 0,
+	      ((LINEMAPS_ALLOCATED (set, macro_map_p)
+		- LINEMAPS_USED (set, macro_map_p))
+	       * sizeof (struct line_map)));
     }
+  else
+    result =
+      &LINEMAPS_MAPS (set, macro_map_p)[LINEMAPS_USED (set, macro_map_p)];
+
+  LINEMAPS_USED (set, macro_map_p)++;
+
+  result->reason = reason;
+  return result;
 }
 
 /* Add a mapping of logical source line to physical source file and
@@ -90,23 +135,24 @@ linemap_add (struct line_maps *set, enum lc_reason reason,
   struct line_map *map;
   source_location start_location = set->highest_location + 1;
 
-  if (set->used && start_location < set->maps[set->used - 1].start_location)
-    abort ();
+  linemap_assert (!(LINEMAPS_ORDINARY_USED (set)
+		    && (start_location
+			< MAP_START_LOCATION (LINEMAPS_LAST_ORDINARY_MAP (set)))));
+
+  /* When we enter the file for the first time reason cannot be
+     LC_RENAME.  */
+  linemap_assert (!(set->depth == 0 && reason == LC_RENAME));
 
-  if (set->used == set->allocated)
+  /* If we are leaving the main file, return a NULL map.  */
+  if (reason == LC_LEAVE
+      && MAIN_FILE_P (LINEMAPS_LAST_ORDINARY_MAP (set))
+      && to_file == NULL)
     {
-      line_map_realloc reallocator
-	= set->reallocator ? set->reallocator : xrealloc;
-      set->allocated = 2 * set->allocated + 256;
-      set->maps
-	= (struct line_map *) (*reallocator) (set->maps,
-					      set->allocated
-					      * sizeof (struct line_map));
-      memset (&set->maps[set->used], 0, ((set->allocated - set->used)
-					 * sizeof (struct line_map)));
+      set->depth--;
+      return NULL;
     }
 
-  map = &set->maps[set->used];
+  map = new_linemap (set, reason);
 
   if (to_file && *to_file == '\0' && reason != LC_RENAME_VERBATIM)
     to_file = "<stdin>";
@@ -114,29 +160,35 @@ linemap_add (struct line_maps *set, enum lc_reason reason,
   if (reason == LC_RENAME_VERBATIM)
     reason = LC_RENAME;
 
-  if (set->depth == 0 && reason == LC_RENAME)
-    abort ();
-
   if (reason == LC_LEAVE)
     {
+      /* When we are just leaving an "included" file, and jump to the next
+	 location inside the "includer" right after the #include
+	 "included", this variable points the map in use right before the
+	 #include "included", inside the same "includer" file.  */
       struct line_map *from;
       bool error;
 
       if (MAIN_FILE_P (map - 1))
 	{
-	  if (to_file == NULL)
-	    {
-	      set->depth--;
-	      return NULL;
-	    }
+	  /* So this _should_ means we are leaving the main file --
+	     effectively ending the compilation unit. But to_file not
+	     being NULL means the caller thinks we are leaving to
+	     another file. This is an erroneous behaviour but we'll
+	     try to recover from it. Let's pretend we are not leaving
+	     the main file.  */
 	  error = true;
           reason = LC_RENAME;
           from = map - 1;
 	}
       else
 	{
+	  /* (MAP - 1) points to the map we are leaving. The
+	     map from which (MAP - 1) got included should be the map
+	     that comes right before MAP in the same file.  */
 	  from = INCLUDED_FROM (set, map - 1);
-	  error = to_file && filename_cmp (from->to_file, to_file);
+	  error = to_file && filename_cmp (ORDINARY_MAP_FILE_NAME (from),
+					   to_file);
 	}
 
       /* Depending upon whether we are handling preprocessed input or
@@ -148,55 +200,176 @@ linemap_add (struct line_maps *set, enum lc_reason reason,
       /* A TO_FILE of NULL is special - we use the natural values.  */
       if (error || to_file == NULL)
 	{
-	  to_file = from->to_file;
+	  to_file = ORDINARY_MAP_FILE_NAME (from);
 	  to_line = SOURCE_LINE (from, from[1].start_location);
-	  sysp = from->sysp;
+	  sysp = ORDINARY_MAP_IN_SYSTEM_HEADER_P (from);
 	}
     }
 
-  map->reason = reason;
-  map->sysp = sysp;
-  map->start_location = start_location;
-  map->to_file = to_file;
-  map->to_line = to_line;
-  set->cache = set->used++;
-  map->column_bits = 0;
+  linemap_assert (reason != LC_ENTER_MACRO);
+  ORDINARY_MAP_IN_SYSTEM_HEADER_P (map) = sysp;
+  MAP_START_LOCATION (map) = start_location;
+  ORDINARY_MAP_FILE_NAME (map) = to_file;
+  ORDINARY_MAP_STARTING_LINE_NUMBER (map) = to_line;
+  LINEMAPS_ORDINARY_CACHE (set) = LINEMAPS_ORDINARY_USED (set) - 1;
+  ORDINARY_MAP_NUMBER_OF_COLUMN_BITS (map) = 0;
   set->highest_location = start_location;
   set->highest_line = start_location;
   set->max_column_hint = 0;
 
   if (reason == LC_ENTER)
     {
-      map->included_from = set->depth == 0 ? -1 : (int) (set->used - 2);
+      ORDINARY_MAP_INCLUDER_FILE_INDEX (map) = 
+	set->depth == 0 ? -1 : (int) (LINEMAPS_ORDINARY_USED (set) - 2);
       set->depth++;
       if (set->trace_includes)
 	trace_include (set, map);
     }
   else if (reason == LC_RENAME)
-    map->included_from = map[-1].included_from;
+    ORDINARY_MAP_INCLUDER_FILE_INDEX (map) =
+      ORDINARY_MAP_INCLUDER_FILE_INDEX (&map[-1]);
   else if (reason == LC_LEAVE)
     {
       set->depth--;
-      map->included_from = INCLUDED_FROM (set, map - 1)->included_from;
+      ORDINARY_MAP_INCLUDER_FILE_INDEX (map) =
+	ORDINARY_MAP_INCLUDER_FILE_INDEX (INCLUDED_FROM (set, map - 1));
     }
 
   return map;
 }
 
+/* Returns TRUE if the line table set tracks token locations accross
+   macro expansion, FALSE otherwise.  */
+
+bool
+linemap_tracks_macro_expansion_locs_p (struct line_maps *set)
+{
+  return LINEMAPS_MACRO_MAPS (set) != NULL;
+}
+
+/* Create a macro map.  A macro map encodes source locations of tokens
+   that are part of a macro replacement-list, at a macro expansion
+   point.  See the extensive comments of struct line_map and struct
+   line_map_macro, in line-map.h.
+
+   This map shall be created when the macro is expanded.  The map
+   encodes the source location of the expansion point of the macro as
+   well as the "original" source location of each token that is part
+   of the macro replacement-list.  If a macro is defined but never
+   expanded, it has no macro map.  SET is the set of maps the macro
+   map should be part of.  MACRO_NODE is the macro which the new macro
+   map should encode source locations for.  EXPANSION is the location
+   of the expansion point of MACRO. For function-like macros
+   invocations, it's best to make it point to the closing parenthesis
+   of the macro, rather than the the location of the first character
+   of the macro.  NUM_TOKENS is the number of tokens that are part of
+   the replacement-list of MACRO.
+
+   Note that when we run out of the integer space available for source
+   locations, this function returns NULL.  In that case, callers of
+   this function cannot encode {line,column} pairs into locations of
+   macro tokens anymore.  */
+
+const struct line_map *
+linemap_enter_macro (struct line_maps *set, struct cpp_hashnode *macro_node,
+		     source_location expansion, unsigned int num_tokens)
+{
+  struct line_map *map;
+  source_location start_location;
+  line_map_realloc reallocator
+    = set->reallocator ? set->reallocator : xrealloc;
+
+  start_location = LINEMAPS_MACRO_LOWEST_LOCATION (set) - num_tokens;
+
+  if (start_location <= set->highest_line
+      || start_location > LINEMAPS_MACRO_LOWEST_LOCATION (set))
+    /* We ran out of macro map space.   */
+    return NULL;
+
+  map = new_linemap (set, LC_ENTER_MACRO);
+
+  MAP_START_LOCATION (map) = start_location;
+  MACRO_MAP_MACRO (map) = macro_node;
+  MACRO_MAP_NUM_MACRO_TOKENS (map) = num_tokens;
+  MACRO_MAP_LOCATIONS (map)
+    = (source_location*) reallocator (NULL,
+				      2 * num_tokens
+				      * sizeof (source_location));
+  MACRO_MAP_EXPANSION_POINT_LOCATION (map) = expansion;
+  memset (MACRO_MAP_LOCATIONS (map), 0,
+	  num_tokens * sizeof (source_location));
+
+  LINEMAPS_MACRO_CACHE (set) = LINEMAPS_MACRO_USED (set) - 1;
+  set->max_column_hint = 0;
+
+  return map;
+}
+
+/* Create and return a virtual location for a token that is part of a
+   macro expansion-list at a macro expansion point.  See the comment
+   inside struct line_map_macro to see what an expansion-list exactly
+   is.
+
+   A call to this function must come after a call to
+   linemap_enter_macro.
+
+   MAP is the map into which the source location is created.  TOKEN_NO
+   is the index of the token in the macro replacement-list, starting
+   at number 0.
+
+   ORIG_LOC is the location of the token outside of this macro
+   expansion.  If the token comes originally from the macro
+   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,
+   either of the token itself or of a macro parameter that it
+   replaces.  */
+
+source_location
+linemap_add_macro_token (const struct line_map *map,
+			 unsigned int token_no,
+			 source_location orig_loc,
+			 source_location orig_parm_replacement_loc)
+{
+  source_location result;
+
+  linemap_assert (linemap_macro_expansion_map_p (map));
+  linemap_assert (token_no < MACRO_MAP_NUM_MACRO_TOKENS (map));
+
+  MACRO_MAP_LOCATIONS (map)[2 * token_no] = orig_loc;
+  MACRO_MAP_LOCATIONS (map)[2 * token_no + 1] = orig_parm_replacement_loc;
+
+  result = MAP_START_LOCATION (map) + token_no;
+  return result;
+}
+
+/* Return a source_location for the start (i.e. column==0) of
+   (physical) line TO_LINE in the current source file (as in the
+   most recent linemap_add).   MAX_COLUMN_HINT is the highest column
+   number we expect to use in this line (but it does not change
+   the highest_location).  */
+
 source_location
 linemap_line_start (struct line_maps *set, linenum_type to_line,
 		    unsigned int max_column_hint)
 {
-  struct line_map *map = &set->maps[set->used - 1];
+  struct line_map *map = LINEMAPS_LAST_ORDINARY_MAP (set);
   source_location highest = set->highest_location;
   source_location r;
-  linenum_type last_line = SOURCE_LINE (map, set->highest_line);
+  linenum_type last_line =
+    SOURCE_LINE (map, set->highest_line);
   int line_delta = to_line - last_line;
   bool add_map = false;
+
   if (line_delta < 0
-      || (line_delta > 10 && line_delta * map->column_bits > 1000)
-      || (max_column_hint >= (1U << map->column_bits))
-      || (max_column_hint <= 80 && map->column_bits >= 10))
+      || (line_delta > 10
+	  && line_delta * ORDINARY_MAP_NUMBER_OF_COLUMN_BITS (map) > 1000)
+      || (max_column_hint >= (1U << ORDINARY_MAP_NUMBER_OF_COLUMN_BITS (map)))
+      || (max_column_hint <= 80
+	  && ORDINARY_MAP_NUMBER_OF_COLUMN_BITS (map) >= 10))
     {
       add_map = true;
     }
@@ -224,16 +397,27 @@ linemap_line_start (struct line_maps *set, linenum_type to_line,
       /* Allocate the new line_map.  However, if the current map only has a
 	 single line we can sometimes just increase its column_bits instead. */
       if (line_delta < 0
-	  || last_line != map->to_line
+	  || last_line != ORDINARY_MAP_STARTING_LINE_NUMBER (map)
 	  || SOURCE_COLUMN (map, highest) >= (1U << column_bits))
-	map = (struct line_map *) linemap_add (set, LC_RENAME, map->sysp,
-					       map->to_file, to_line);
-      map->column_bits = column_bits;
-      r = map->start_location + ((to_line - map->to_line) << column_bits);
+	map = (struct line_map *) linemap_add (set, LC_RENAME,
+					       ORDINARY_MAP_IN_SYSTEM_HEADER_P
+					       (map),
+					       ORDINARY_MAP_FILE_NAME (map),
+					       to_line);
+      ORDINARY_MAP_NUMBER_OF_COLUMN_BITS (map) = column_bits;
+      r = (MAP_START_LOCATION (map)
+	   + ((to_line - ORDINARY_MAP_STARTING_LINE_NUMBER (map))
+	      << column_bits));
     }
   else
     r = highest - SOURCE_COLUMN (map, highest)
-      + (line_delta << map->column_bits);
+      + (line_delta << ORDINARY_MAP_NUMBER_OF_COLUMN_BITS (map));
+
+  /* Locations of ordinary tokens are always lower than locations of
+     macro tokens.  */
+  if (r >= LINEMAPS_MACRO_LOWEST_LOCATION (set))
+    return 0;
+
   set->highest_line = r;
   if (r > set->highest_location)
     set->highest_location = r;
@@ -241,10 +425,19 @@ linemap_line_start (struct line_maps *set, linenum_type to_line,
   return r;
 }
 
+/* Encode and return a source_location from a column number. The
+   source line considered is the last source line used to call
+   linemap_line_start, i.e, the last source line which a location was
+   encoded from.  */
+
 source_location
 linemap_position_for_column (struct line_maps *set, unsigned int to_column)
 {
   source_location r = set->highest_line;
+
+  linemap_assert
+    (!linemap_macro_expansion_map_p (LINEMAPS_LAST_ORDINARY_MAP (set)));
+
   if (to_column >= set->max_column_hint)
     {
       if (r >= 0xC000000 || to_column > 100000)
@@ -254,7 +447,7 @@ linemap_position_for_column (struct line_maps *set, unsigned int to_column)
 	}
       else
 	{
-	  struct line_map *map = &set->maps[set->used - 1];
+	  struct line_map *map = LINEMAPS_LAST_ORDINARY_MAP (set);
 	  r = linemap_line_start (set, SOURCE_LINE (map, r), to_column + 50);
 	}
     }
@@ -264,25 +457,55 @@ linemap_position_for_column (struct line_maps *set, unsigned int to_column)
   return r;
 }
 
-/* Given a logical line, returns the map from which the corresponding
-   (source file, line) pair can be deduced.  Since the set is built
-   chronologically, the logical lines are monotonic increasing, and so
-   the list is sorted and we can use a binary search.  */
+/* Encode and return a source location from a given line and
+   column.  */
 
-const struct line_map *
+source_location
+linemap_position_for_line_and_column (struct line_map *map,
+				      linenum_type line,
+				      unsigned column)
+{
+  linemap_assert (ORDINARY_MAP_STARTING_LINE_NUMBER (map) <= line);
+
+  return (MAP_START_LOCATION (map)
+	  + ((line - ORDINARY_MAP_STARTING_LINE_NUMBER (map))
+	     << ORDINARY_MAP_NUMBER_OF_COLUMN_BITS (map))
+	  + (column & ((1 << ORDINARY_MAP_NUMBER_OF_COLUMN_BITS (map)) - 1)));
+}
+
+/* Given a virtual source location yielded by a map (either an
+   ordinary or a macro map), returns that map.  */
+
+const struct line_map*
 linemap_lookup (struct line_maps *set, source_location line)
 {
+  if (linemap_location_from_macro_expansion_p (set, line))
+    return linemap_macro_map_lookup (set, line);
+  return linemap_ordinary_map_lookup (set, line);
+}
+
+/* Given a source location yielded by an ordinary map, returns that
+   map.  Since the set is built chronologically, the logical lines are
+   monotonic increasing, and so the list is sorted and we can use a
+   binary search.  */
+
+static const struct line_map *
+linemap_ordinary_map_lookup (struct line_maps *set, source_location line)
+{
   unsigned int md, mn, mx;
-  const struct line_map *cached;
+  const struct line_map *cached, *result;
 
-  mn = set->cache;
-  mx = set->used;
+  if (set ==  NULL || line < RESERVED_LOCATION_COUNT)
+    return NULL;
+
+  mn = LINEMAPS_ORDINARY_CACHE (set);
+  mx = LINEMAPS_ORDINARY_USED (set);
   
-  cached = &set->maps[mn];
+  cached = LINEMAPS_ORDINARY_MAP_AT (set, mn);
   /* We should get a segfault if no line_maps have been added yet.  */
-  if (line >= cached->start_location)
+  if (line >= MAP_START_LOCATION (cached))
     {
-      if (mn + 1 == mx || line < cached[1].start_location)
+      if (mn + 1 == mx || line < MAP_START_LOCATION (&cached[1]))
 	return cached;
     }
   else
@@ -294,14 +517,345 @@ linemap_lookup (struct line_maps *set, source_location line)
   while (mx - mn > 1)
     {
       md = (mn + mx) / 2;
-      if (set->maps[md].start_location > line)
+      if (MAP_START_LOCATION (LINEMAPS_ORDINARY_MAP_AT (set, md)) > line)
 	mx = md;
       else
 	mn = md;
     }
 
-  set->cache = mn;
-  return &set->maps[mn];
+  LINEMAPS_ORDINARY_CACHE (set) = mn;
+  result = LINEMAPS_ORDINARY_MAP_AT (set, mn);
+  linemap_assert (line >= MAP_START_LOCATION (result));
+  return result;
+}
+
+/* Given a source location yielded by a macro map, returns that map.
+   Since the set is built chronologically, the logical lines are
+   monotonic decreasing, and so the list is sorted and we can use a
+   binary search.  */
+
+static const struct line_map*
+linemap_macro_map_lookup (struct line_maps *set, source_location line)
+{
+  unsigned int md, mn, mx;
+  const struct line_map *cached, *result;
+
+  linemap_assert (line >= LINEMAPS_MACRO_LOWEST_LOCATION (set));
+
+  if (set ==  NULL)
+    return NULL;
+
+  mn = LINEMAPS_MACRO_CACHE (set);
+  mx = LINEMAPS_MACRO_USED (set);
+  cached = LINEMAPS_MACRO_MAP_AT (set, mn);
+  
+  if (line >= MAP_START_LOCATION (cached))
+    {
+      if (mn == 0 || line < MAP_START_LOCATION (&cached[-1]))
+	return cached;
+      mx = mn - 1;
+      mn = 0;
+    }
+
+  do 
+    {
+      md = (mx + mn) / 2;
+      if (MAP_START_LOCATION (LINEMAPS_MACRO_MAP_AT (set, md)) > line)
+	mn = md;
+      else
+	mx = md;
+    } while (mx - mn > 1);
+
+  LINEMAPS_MACRO_CACHE (set) = mx;
+  result = LINEMAPS_MACRO_MAP_AT (set, LINEMAPS_MACRO_CACHE (set));
+  linemap_assert (MAP_START_LOCATION (result) <= line);
+
+  return result;
+}
+
+/* Return TRUE if MAP encodes locations coming from a macro
+   replacement-list at macro expansion point.  */
+
+bool
+linemap_macro_expansion_map_p (const struct line_map *map)
+{
+  if (!map)
+    return false;
+  return (map->reason == LC_ENTER_MACRO);
+}
+
+/* If LOCATION is the locus of a token in a replacement-list of a
+   macro expansion return the location of the macro expansion point.
+
+   Read the comments of struct line_map and struct line_map_macro in
+   line-map.h to understand what a macro expansion point is.  */
+
+source_location
+linemap_macro_map_loc_to_exp_point (const struct line_map *map,
+				    source_location location)
+{
+  unsigned token_no;
+
+  linemap_assert (linemap_macro_expansion_map_p (map)
+		  && location >= MAP_START_LOCATION (map));
+
+  /* Make sure LOCATION is correct.  */
+  token_no = location - MAP_START_LOCATION (map);
+  linemap_assert (token_no <  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.  */
+
+source_location
+linemap_macro_map_loc_to_def_point (const struct line_map *map,
+				    source_location location)
+{
+  unsigned token_no;
+
+  linemap_assert (linemap_macro_expansion_map_p (map)
+		  && location >= MAP_START_LOCATION (map));
+  linemap_assert (location >= RESERVED_LOCATION_COUNT);
+
+  token_no = location - MAP_START_LOCATION (map);
+  linemap_assert (token_no < MACRO_MAP_NUM_MACRO_TOKENS (map));
+
+  location = MACRO_MAP_LOCATIONS (map)[2 * token_no + 1];
+
+  return location;
+}
+
+/* If LOCATION is the locus of a token that is an argument of a
+   function-like macro M and appears in the expansion of M, return the
+   locus of that argument in the context of the caller of M.
+
+   In other words, this returns the xI location presented in the
+   comments of line_map_macro above.  */
+source_location
+linemap_macro_map_loc_unwind_toward_spelling (const struct line_map* map,
+					      source_location location)
+{
+  unsigned token_no;
+
+  linemap_assert (linemap_macro_expansion_map_p (map)
+		  && location >= MAP_START_LOCATION (map));
+  linemap_assert (location >= RESERVED_LOCATION_COUNT);
+
+  token_no = location - MAP_START_LOCATION (map);
+  linemap_assert (token_no < MACRO_MAP_NUM_MACRO_TOKENS (map));
+
+  location = MACRO_MAP_LOCATIONS (map)[2 * token_no];
+  
+  return location;
+}
+
+/* Return the source line number corresponding to source location
+   LOCATION.  SET is the line map set LOCATION comes from.  If
+   LOCATION is the source location of token that is part of the
+   replacement-list of a macro expansion return the line number of the
+   macro expansion point.  */
+
+int
+linemap_get_expansion_line (struct line_maps *set,
+			    source_location location)
+{
+  const struct line_map *map = NULL;
+
+  if (location < RESERVED_LOCATION_COUNT)
+    return 0;
+
+  location =
+    linemap_macro_loc_to_exp_point (set, location, &map);
+
+  return SOURCE_LINE (map, location);
+}
+
+/* Return the path of the file corresponding to source code location
+   LOCATION.
+
+   If LOCATION is the source location of token that is part of the
+   replacement-list of a macro expansion return the file path of the
+   macro expansion point.
+
+   SET is the line map set LOCATION comes from.  */
+
+const char*
+linemap_get_expansion_filename (struct line_maps *set,
+				source_location location)
+{
+  const struct line_map *map = NULL;
+
+  if (location < RESERVED_LOCATION_COUNT)
+    return NULL;
+
+  location =
+    linemap_macro_loc_to_exp_point (set, location, &map);
+
+  return LINEMAP_FILE (map);
+}
+
+/* Return the name of the macro associated to MACRO_MAP.  */
+
+const char*
+linemap_map_get_macro_name (const struct line_map* macro_map)
+{
+  linemap_assert (macro_map && linemap_macro_expansion_map_p (macro_map));
+  return (const char*) NODE_NAME (MACRO_MAP_MACRO (macro_map));
+}
+
+/* Return a positive value if LOCATION is the locus of a token that is
+   located in a system header, O otherwise. It returns 1 if LOCATION
+   is the locus of a token that is located in a system header, and 2
+   if LOCATION is the locus of a token located in a C system header
+   that therefore needs to be extern "C" protected in C++.
+
+   Note that this function returns 1 if LOCATION belongs to a token
+   that is part of a macro replacement-list defined in a system
+   header, but expanded in a non-system file.  */
+
+int
+linemap_location_in_system_header_p (struct line_maps *set,
+				     source_location location)
+{
+  const struct line_map *map = NULL;
+
+  if (location < RESERVED_LOCATION_COUNT)
+    return false;
+
+  location =
+    linemap_resolve_location (set, location, LRK_SPELLING_LOCATION, &map);
+
+  return LINEMAP_SYSP (map);
+}
+
+/* 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,
+					 source_location location)
+{
+  linemap_assert (location <= MAX_SOURCE_LOCATION
+		  && (set->highest_location
+		      < LINEMAPS_MACRO_LOWEST_LOCATION (set)));
+  if (set == NULL)
+    return false;
+  return (location > set->highest_location);
+}
+
+/* Given two virtual locations *LOC0 and *LOC1, return the first
+   common macro map in their macro expansion histories.  Return NULL
+   if no common macro was found.  *LOC0 (resp. *LOC1) is set to the
+   virtual location of the token inside the resulting macro.  */
+
+static const struct line_map*
+first_map_in_common_1 (struct line_maps *set,
+		       source_location *loc0,
+		       source_location *loc1)
+{
+  source_location l0 = *loc0, l1 = *loc1;
+  const struct line_map *map0 = linemap_lookup (set, l0),
+    *map1 = linemap_lookup (set, l1);
+
+  while (linemap_macro_expansion_map_p (map0)
+	 && linemap_macro_expansion_map_p (map1)
+	 && (map0 != map1))
+    {
+      if (MAP_START_LOCATION (map0) < MAP_START_LOCATION (map1))
+	{
+	  l0 = linemap_macro_map_loc_to_exp_point (map0, l0);
+	  map0 = linemap_lookup (set, l0);
+	}
+      else
+	{
+	  l1 = linemap_macro_map_loc_to_exp_point (map1, l1);
+	  map1 = linemap_lookup (set, l1);
+	}
+    }
+
+  if (map0 == map1)
+    {
+      *loc0 = l0;
+      *loc1 = l1;
+      return map0;
+    }
+  return NULL;
+}
+
+/* Given two virtual locations LOC0 and LOC1, return the first common
+   macro map in their macro expansion histories.  Return NULL if no
+   common macro was found.  *RES_LOC0 (resp. *RES_LOC1) is set to the
+   virtual location of the token inside the resulting macro, upon
+   return of a non-NULL result.  */
+
+static const struct line_map*
+first_map_in_common (struct line_maps *set,
+		     source_location loc0,
+		     source_location loc1,
+		     source_location  *res_loc0,
+		     source_location  *res_loc1)
+{
+  *res_loc0 = loc0;
+  *res_loc1 = loc1;
+
+  return first_map_in_common_1 (set, res_loc0, res_loc1);
+}
+
+/* Return a positive value if PRE denotes the location of a token that
+   comes before the token of POST, 0 if PRE denotes the location of
+   the same token as the token for POST, and a negative value
+   otherwise.  */
+
+int
+linemap_compare_locations (struct line_maps *set,
+			   source_location  pre,
+			   source_location post)
+{
+  bool pre_virtual_p, post_virtual_p;
+  source_location l0 = pre, l1 = post;
+
+  if (l0 == l1)
+    return 0;
+
+  if ((pre_virtual_p = linemap_location_from_macro_expansion_p (set, l0)))
+    l0 = linemap_resolve_location (set, l0,
+				   LRK_MACRO_EXPANSION_POINT,
+				   NULL);
+
+  if ((post_virtual_p = linemap_location_from_macro_expansion_p (set, l1)))
+    l1 = linemap_resolve_location (set, l1,
+				   LRK_MACRO_EXPANSION_POINT,
+				   NULL);
+
+  if (l0 == l1
+      && pre_virtual_p
+      && post_virtual_p)
+    {
+      /* So pre and post represent two tokens that are present in a
+	 same macro expansion.  Let's see if the token for pre was
+	 before the token for post in that expansion.  */
+      unsigned i0, i1;
+      const struct line_map *map =
+	first_map_in_common (set, pre, post, &l0, &l1);
+
+      if (map == NULL)
+	/* This should not be possible.  */
+	abort ();
+
+      i0 = l0 - MAP_START_LOCATION (map);
+      i1 = l1 - MAP_START_LOCATION (map);
+      return i1 - i0;
+    }
+
+  return l1 - l0;
 }
 
 /* Print an include trace, for e.g. the -H option of the preprocessor.  */
@@ -313,5 +867,241 @@ trace_include (const struct line_maps *set, const struct line_map *map)
 
   while (--i)
     putc ('.', stderr);
-  fprintf (stderr, " %s\n", map->to_file);
+
+  fprintf (stderr, " %s\n", ORDINARY_MAP_FILE_NAME (map));
+}
+
+/* Return the spelling location of the token wherever it comes from,
+   whether part of a macro definition or not.
+
+   This is a subroutine for linemap_resolve_location.  */
+
+static source_location
+linemap_macro_loc_to_spelling_point (struct line_maps *set,
+				     source_location location,
+				     const struct line_map **original_map)
+{
+  struct line_map *map;
+
+  linemap_assert (set && location >= RESERVED_LOCATION_COUNT);
+
+  while (true)
+    {
+      map = (struct line_map*) linemap_lookup (set, location);
+      if (!linemap_macro_expansion_map_p (map))
+	break;
+
+      location =
+	linemap_macro_map_loc_unwind_toward_spelling (map, location);
+    }
+
+  if (original_map)
+    *original_map = map;
+  return location;
+}
+
+/* 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. 
+
+   This is a subroutine of linemap_resolve_location.  */
+
+static source_location
+linemap_macro_loc_to_def_point (struct line_maps *set,
+				source_location location,
+				const struct line_map **original_map)
+{
+  struct line_map *map;
+
+  linemap_assert (set && location >= RESERVED_LOCATION_COUNT);
+
+  while (true)
+    {
+      map = (struct line_map*) linemap_lookup (set, location);
+      if (!linemap_macro_expansion_map_p (map))
+	break;
+
+      location =
+	linemap_macro_map_loc_to_def_point (map, location);
+    }
+
+  if (original_map)
+    *original_map = map;
+  return location;
+}
+
+/* If LOCATION is the source location of a token that belongs to a
+   macro replacement-list -- at a macro expansion point -- then return
+   the location of the topmost expansion point of the macro.  We say
+   topmost because if we are in the context of a nested macro
+   expansion, the function returns the source location of the first
+   macro expansion that triggered the nested expansions.
+
+   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.
+
+   This is a subroutine of linemap_resolve_location.  */
+
+static source_location
+linemap_macro_loc_to_exp_point (struct line_maps *set,
+				source_location location,
+				const struct line_map **original_map)
+{
+  struct line_map *map;
+
+  linemap_assert (set && location >= RESERVED_LOCATION_COUNT);
+
+  while (true)
+    {
+      map = (struct line_map*) linemap_lookup (set, location);
+      if (!linemap_macro_expansion_map_p (map))
+	break;
+      location = linemap_macro_map_loc_to_exp_point (map, location);
+    }
+
+  if (original_map)
+    *original_map = map;
+  return location;
+}
+
+/* Resolve a virtual location into either a spelling location, an
+   expansion point location or a token argument replacement point
+   location.  Return the map that encodes the virtual location as well
+   as the resolved location.
+
+   If LOC is *NOT* the location of a token resulting from the
+   expansion of a macro, then the parameter LRK (which stands for
+   Location Resolution Kind) is ignored and the resulting location
+   just equals the one given in argument.
+
+   Now if LOC *IS* the location of a token resulting from the
+   expansion of a macro, this is what happens.
+
+   * If LRK is set to LRK_MACRO_EXPANSION_POINT
+   -------------------------------
+
+   The virtual location is resolved to the location to the locus of
+   the expansion point of the macro.
+
+   * If LRK is set to LRK_SPELLING_LOCATION
+   -------------------------------------
+
+   The virtual location is resolved to the location to the locus where
+   the token has been spelled in the source. This can follow through
+   all the macro expansions that led to the token.
+
+   * If LRK is set to LRK_MACRO_PARM_REPLACEMENT_POINT
+   --------------------------------------
+
+   If LOC is the locus of a token that is an argument of a
+   function-like macro [replacing a parameter in the replacement list
+   of the macro] the virtual location is resolved to the locus of the
+   parameter that is replaced, in the context of the definition of the
+   macro.
+
+   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 MAP is non-NULL, *MAP is set to the map of the resolved
+   location.  */
+
+source_location
+linemap_resolve_location (struct line_maps *set,
+			  source_location loc,
+			  enum location_resolution_kind lrk,
+			  const struct line_map **map)
+{
+  linemap_assert (set && loc >= RESERVED_LOCATION_COUNT);
+
+  switch (lrk)
+    {
+    case LRK_MACRO_EXPANSION_POINT:
+      loc = linemap_macro_loc_to_exp_point (set, loc, map);
+      break;
+    case LRK_SPELLING_LOCATION:
+      loc = linemap_macro_loc_to_spelling_point (set, loc, map);
+      break;
+    case LRK_MACRO_DEFINITION_LOCATION:
+      loc = linemap_macro_loc_to_def_point (set, loc, map);
+      break;
+    default:
+      abort ();
+    }
+  return loc;
+}
+
+/* 
+   Suppose that LOC is the virtual location of a token T coming from
+   the expansion of a macro M.  This function then steps up to get the
+   location L of the point where M got expanded.  If L is a spelling
+   location inside a macro expansion M', then this function returns
+   the locus of the point where M' was expanded.  Said otherwise, this
+   function returns the location of T in the context that triggered
+   the expansion of M. 
+
+   *LOC_MAP must be set to the map of LOC.  This function then sets it
+   to the map of the returned location.  */
+
+source_location
+linemap_unwind_toward_expansion (struct line_maps *set,
+				 source_location loc,
+				 const struct line_map **map)
+{
+  source_location resolved_location;
+  const struct line_map *resolved_map;
+
+  resolved_location =
+    linemap_macro_map_loc_unwind_toward_spelling (*map, loc);
+  resolved_map = linemap_lookup (set, resolved_location);
+
+  if (!linemap_macro_expansion_map_p (resolved_map))
+    {
+      resolved_location = linemap_macro_map_loc_to_exp_point (*map, loc);
+      resolved_map = linemap_lookup (set, resolved_location);
+    }
+
+  *map = resolved_map;
+  return resolved_location;
+}
+
+/* Expand source code location LOC and return a user readable source
+   code location.  LOC must be a spelling (non-virtual) location.  */
+
+expanded_location
+linemap_expand_location (const struct line_map *map,
+			 source_location loc)
+
+{
+  expanded_location xloc;
+
+  xloc.file = LINEMAP_FILE (map);
+  xloc.line = SOURCE_LINE (map, loc);
+  xloc.column = SOURCE_COLUMN (map, loc);
+  xloc.sysp = LINEMAP_SYSP (map) != 0;
+
+  return xloc;
+}
+
+/* Expand source code location LOC and return a user readable source
+   code location.  LOC can be a virtual location.  The LRK parameter
+   is the same as for linemap_resolve_location.  */
+
+expanded_location
+linemap_expand_location_full (struct line_maps *set,
+			      source_location loc,
+			      enum location_resolution_kind lrk)
+{
+  const struct line_map *map;
+  expanded_location xloc;
+
+  loc = linemap_resolve_location (set, loc, lrk, &map);
+  xloc = linemap_expand_location (map, loc);
+  return xloc;
 }