Support -fdebug-cpp option

[official-gcc.git] / libcpp / line-map.c

/* Map logical line numbers to (source file, line number) pairs.
   Copyright (C) 2001, 2003, 2004, 2007, 2008, 2009, 2010, 2011
   Free Software Foundation, Inc.

This program is free software; you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by the
Free Software Foundation; either version 3, or (at your option) any
later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; see the file COPYING3.  If not see
<http://www.gnu.org/licenses/>.

 In other words, you are welcome to use, share and improve this program.
 You are forbidden to forbid anyone else to use, share and improve
 what you give them.   Help stamp out software-hoarding!  */

#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)
{
  memset (set, 0, sizeof (struct line_maps));
  set->highest_location = RESERVED_LOCATION_COUNT - 1;
  set->highest_line = RESERVED_LOCATION_COUNT - 1;
}

/* Check for and warn about line_maps entered but not exited.  */

void
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 = 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",
             ORDINARY_MAP_FILE_NAME (map));
}

/* 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)
{
  /* 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))
    {
      /* We ran out of allocated line maps. Let's allocate more.  */

      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
   line number.

   The text pointed to by TO_FILE must have a lifetime
   at least as long as the final call to lookup_line ().  An empty
   TO_FILE means standard input.  If reason is LC_LEAVE, and
   TO_FILE is NULL, then TO_FILE, TO_LINE and SYSP are given their
   natural values considering the file we are returning to.

   FROM_LINE should be monotonic increasing across calls to this
   function.  A call to this function can relocate the previous set of
   maps, so any stored line_map pointers should not be used.  */

const struct line_map *
linemap_add (struct line_maps *set, enum lc_reason reason,
             unsigned int sysp, const char *to_file, linenum_type to_line)
{
  struct line_map *map;
  source_location start_location = set->highest_location + 1;

  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 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)
    {
      set->depth--;
      return NULL;
    }

  map = new_linemap (set, reason);

  if (to_file && *to_file == '\0' && reason != LC_RENAME_VERBATIM)
    to_file = "<stdin>";

  if (reason == LC_RENAME_VERBATIM)
    reason = LC_RENAME;

  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))
        {
          /* 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 (ORDINARY_MAP_FILE_NAME (from),
                                           to_file);
        }

      /* Depending upon whether we are handling preprocessed input or
         not, this can be a user error or an ICE.  */
      if (error)
        fprintf (stderr, "line-map.c: file \"%s\" left but not entered\n",
                 to_file);

      /* A TO_FILE of NULL is special - we use the natural values.  */
      if (error || to_file == NULL)
        {
          to_file = ORDINARY_MAP_FILE_NAME (from);
          to_line = SOURCE_LINE (from, from[1].start_location);
          sysp = ORDINARY_MAP_IN_SYSTEM_HEADER_P (from);
        }
    }

  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)
    {
      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)
    ORDINARY_MAP_INCLUDER_FILE_INDEX (map) =
      ORDINARY_MAP_INCLUDER_FILE_INDEX (&map[-1]);
  else if (reason == LC_LEAVE)
    {
      set->depth--;
      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 = LINEMAPS_LAST_ORDINARY_MAP (set);
  source_location highest = set->highest_location;
  source_location r;
  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 * 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;
    }
  else
    max_column_hint = set->max_column_hint;
  if (add_map)
    {
      int column_bits;
      if (max_column_hint > 100000 || highest > 0xC0000000)
        {
          /* If the column number is ridiculous or we've allocated a huge
             number of source_locations, give up on column numbers. */
          max_column_hint = 0;
          if (highest >0xF0000000)
            return 0;
          column_bits = 0;
        }
      else
        {
          column_bits = 7;
          while (max_column_hint >= (1U << column_bits))
            column_bits++;
          max_column_hint = 1U << column_bits;
        }
      /* 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 != ORDINARY_MAP_STARTING_LINE_NUMBER (map)
          || SOURCE_COLUMN (map, highest) >= (1U << 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 << 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;
  set->max_column_hint = max_column_hint;
  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)
        {
          /* Running low on source_locations - disable column numbers.  */
          return r;
        }
      else
        {
          struct line_map *map = LINEMAPS_LAST_ORDINARY_MAP (set);
          r = linemap_line_start (set, SOURCE_LINE (map, r), to_column + 50);
        }
    }
  r = r + to_column;
  if (r >= set->highest_location)
    set->highest_location = r;
  return r;
}

/* Encode and return a source location from a given line and
   column.  */

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, *result;

  if (set ==  NULL || line < RESERVED_LOCATION_COUNT)
    return NULL;

  mn = LINEMAPS_ORDINARY_CACHE (set);
  mx = LINEMAPS_ORDINARY_USED (set);
  
  cached = LINEMAPS_ORDINARY_MAP_AT (set, mn);
  /* We should get a segfault if no line_maps have been added yet.  */
  if (line >= MAP_START_LOCATION (cached))
    {
      if (mn + 1 == mx || line < MAP_START_LOCATION (&cached[1]))
        return cached;
    }
  else
    {
      mx = mn;
      mn = 0;
    }

  while (mx - mn > 1)
    {
      md = (mn + mx) / 2;
      if (MAP_START_LOCATION (LINEMAPS_ORDINARY_MAP_AT (set, md)) > line)
        mx = md;
      else
        mn = md;
    }

  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.  */

static void
trace_include (const struct line_maps *set, const struct line_map *map)
{
  unsigned int i = set->depth;

  while (--i)
    putc ('.', stderr);

  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;
}

/* Dump debugging information about source location LOC into the file
   stream STREAM. SET is the line map set LOC comes from.  */

void
linemap_dump_location (struct line_maps *set,
                       source_location loc,
                       FILE *stream)
{
  const struct line_map *map;
  source_location location;
  const char *path, *from;
  int l,c,s,e;

  if (loc == 0)
    return;

  location =
    linemap_resolve_location (set, loc, LRK_MACRO_DEFINITION_LOCATION, &map);
  path = LINEMAP_FILE (map);

  l = SOURCE_LINE (map, location);
  c = SOURCE_COLUMN (map, location);
  s = LINEMAP_SYSP (map) != 0;
  e = location != loc;

  if (e)
    from = "N/A";
  else
    from = (INCLUDED_FROM (set, map))
      ? LINEMAP_FILE (INCLUDED_FROM (set, map))
      : "<NULL>";

  /* P: path, L: line, C: column, S: in-system-header, M: map address,
     E: macro expansion?.   */
  fprintf (stream, "{P:%s;F:%s;L:%d;C:%d;S:%d;M:%p;E:%d,LOC:%d}",
           path, from, l, c, s, (void*)map, e, loc);
}