libcpp/line-map.c

   1 /* Map logical line numbers to (source file, line number) pairs.
   2    Copyright (C) 2001, 2003, 2004, 2007, 2008, 2009
   3    Free Software Foundation, Inc.
   4
   5 This program is free software; you can redistribute it and/or modify it
   6 under the terms of the GNU General Public License as published by the
   7 Free Software Foundation; either version 2, or (at your option) any
   8 later version.
   9
  10 This program is distributed in the hope that it will be useful,
  11 but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13 GNU General Public License for more details.
  14
  15 You should have received a copy of the GNU General Public License
  16 along with this program; if not, write to the Free Software
  17 Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  18
  19  In other words, you are welcome to use, share and improve this program.
  20  You are forbidden to forbid anyone else to use, share and improve
  21  what you give them.   Help stamp out software-hoarding!  */
  22
  23 #include "config.h"
  24 #include "system.h"
  25 #include "line-map.h"
  26
  27 static void trace_include (const struct line_maps *, const struct line_map *);
  28
  29 /* Initialize a line map set.  */
  30
  31 void
  32 linemap_init (struct line_maps *set)
  33 {
  34   set->maps = NULL;
  35   set->allocated = 0;
  36   set->used = 0;
  37   set->last_listed = -1;
  38   set->trace_includes = false;
  39   set->depth = 0;
  40   set->cache = 0;
  41   set->highest_location = 0;
  42   set->highest_line = 0;
  43   set->max_column_hint = 0;
  44   set->reallocator = 0;
  45 }
  46
  47 /* Check for and warn about line_maps entered but not exited.  */
  48
  49 void
  50 linemap_check_files_exited (struct line_maps *set)
  51 {
  52   struct line_map *map;
  53   /* Depending upon whether we are handling preprocessed input or
  54      not, this can be a user error or an ICE.  */
  55   for (map = &set->maps[set->used - 1]; ! MAIN_FILE_P (map);
  56        map = INCLUDED_FROM (set, map))
  57     fprintf (stderr, "line-map.c: file \"%s\" entered but not left\n",
  58              map->to_file);
  59 }
  60
  61 /* Free a line map set.  */
  62
  63 void
  64 linemap_free (struct line_maps *set)
  65 {
  66   if (set->maps)
  67     {
  68       linemap_check_files_exited (set);
  69
  70       free (set->maps);
  71     }
  72 }
  73
  74 /* Add a mapping of logical source line to physical source file and
  75    line number.
  76
  77    The text pointed to by TO_FILE must have a lifetime
  78    at least as long as the final call to lookup_line ().  An empty
  79    TO_FILE means standard input.  If reason is LC_LEAVE, and
  80    TO_FILE is NULL, then TO_FILE, TO_LINE and SYSP are given their
  81    natural values considering the file we are returning to.
  82
  83    FROM_LINE should be monotonic increasing across calls to this
  84    function.  A call to this function can relocate the previous set of
  85    maps, so any stored line_map pointers should not be used.  */
  86
  87 const struct line_map *
  88 linemap_add (struct line_maps *set, enum lc_reason reason,
  89              unsigned int sysp, const char *to_file, linenum_type to_line)
  90 {
  91   struct line_map *map;
  92   source_location start_location = set->highest_location + 1;
  93
  94   if (set->used && start_location < set->maps[set->used - 1].start_location)
  95     abort ();
  96
  97   if (set->used == set->allocated)
  98     {
  99       line_map_realloc reallocator
 100         = set->reallocator ? set->reallocator : xrealloc;
 101       set->allocated = 2 * set->allocated + 256;
 102       set->maps
 103         = (struct line_map *) (*reallocator) (set->maps,
 104                                               set->allocated
 105                                               * sizeof (struct line_map));
 106       memset (&set->maps[set->used], 0, ((set->allocated - set->used)
 107                                          * sizeof (struct line_map)));
 108     }
 109
 110   map = &set->maps[set->used];
 111
 112   if (to_file && *to_file == '\0')
 113     to_file = "<stdin>";
 114
 115   /* If we don't keep our line maps consistent, we can easily
 116      segfault.  Don't rely on the client to do it for us.  */
 117   if (set->depth == 0)
 118     reason = LC_ENTER;
 119   else if (reason == LC_LEAVE)
 120     {
 121       struct line_map *from;
 122       bool error;
 123
 124       if (MAIN_FILE_P (map - 1))
 125         {
 126           if (to_file == NULL)
 127             {
 128               set->depth--;
 129               return NULL;
 130             }
 131           error = true;
 132           reason = LC_RENAME;
 133           from = map - 1;
 134         }
 135       else
 136         {
 137           from = INCLUDED_FROM (set, map - 1);
 138           error = to_file && strcmp (from->to_file, to_file);
 139         }
 140
 141       /* Depending upon whether we are handling preprocessed input or
 142          not, this can be a user error or an ICE.  */
 143       if (error)
 144         fprintf (stderr, "line-map.c: file \"%s\" left but not entered\n",
 145                  to_file);
 146
 147       /* A TO_FILE of NULL is special - we use the natural values.  */
 148       if (error || to_file == NULL)
 149         {
 150           to_file = from->to_file;
 151           to_line = SOURCE_LINE (from, from[1].start_location);
 152           sysp = from->sysp;
 153         }
 154     }
 155
 156   map->reason = reason;
 157   map->sysp = sysp;
 158   map->start_location = start_location;
 159   map->to_file = to_file;
 160   map->to_line = to_line;
 161   set->cache = set->used++;
 162   map->column_bits = 0;
 163   set->highest_location = start_location;
 164   set->highest_line = start_location;
 165   set->max_column_hint = 0;
 166
 167   if (reason == LC_ENTER)
 168     {
 169       map->included_from = set->depth == 0 ? -1 : (int) (set->used - 2);
 170       set->depth++;
 171       if (set->trace_includes)
 172         trace_include (set, map);
 173     }
 174   else if (reason == LC_RENAME)
 175     map->included_from = map[-1].included_from;
 176   else if (reason == LC_LEAVE)
 177     {
 178       set->depth--;
 179       map->included_from = INCLUDED_FROM (set, map - 1)->included_from;
 180     }
 181
 182   return map;
 183 }
 184
 185 source_location
 186 linemap_line_start (struct line_maps *set, linenum_type to_line,
 187                     unsigned int max_column_hint)
 188 {
 189   struct line_map *map = &set->maps[set->used - 1];
 190   source_location highest = set->highest_location;
 191   source_location r;
 192   linenum_type last_line = SOURCE_LINE (map, set->highest_line);
 193   int line_delta = to_line - last_line;
 194   bool add_map = false;
 195   if (line_delta < 0
 196       || (line_delta > 10 && line_delta * map->column_bits > 1000)
 197       || (max_column_hint >= (1U << map->column_bits))
 198       || (max_column_hint <= 80 && map->column_bits >= 10))
 199     {
 200       add_map = true;
 201     }
 202   else
 203     max_column_hint = set->max_column_hint;
 204   if (add_map)
 205     {
 206       int column_bits;
 207       if (max_column_hint > 100000 || highest > 0xC0000000)
 208         {
 209           /* If the column number is ridiculous or we've allocated a huge
 210              number of source_locations, give up on column numbers. */
 211           max_column_hint = 0;
 212           if (highest >0xF0000000)
 213             return 0;
 214           column_bits = 0;
 215         }
 216       else
 217         {
 218           column_bits = 7;
 219           while (max_column_hint >= (1U << column_bits))
 220             column_bits++;
 221           max_column_hint = 1U << column_bits;
 222         }
 223       /* Allocate the new line_map.  However, if the current map only has a
 224          single line we can sometimes just increase its column_bits instead. */
 225       if (line_delta < 0
 226           || last_line != map->to_line
 227           || SOURCE_COLUMN (map, highest) >= (1U << column_bits))
 228         map = (struct line_map *) linemap_add (set, LC_RENAME, map->sysp,
 229                                                map->to_file, to_line);
 230       map->column_bits = column_bits;
 231       r = map->start_location + ((to_line - map->to_line) << column_bits);
 232     }
 233   else
 234     r = highest - SOURCE_COLUMN (map, highest)
 235       + (line_delta << map->column_bits);
 236   set->highest_line = r;
 237   if (r > set->highest_location)
 238     set->highest_location = r;
 239   set->max_column_hint = max_column_hint;
 240   return r;
 241 }
 242
 243 source_location
 244 linemap_position_for_column (struct line_maps *set, unsigned int to_column)
 245 {
 246   source_location r = set->highest_line;
 247   if (to_column >= set->max_column_hint)
 248     {
 249       if (r >= 0xC000000 || to_column > 100000)
 250         {
 251           /* Running low on source_locations - disable column numbers.  */
 252           return r;
 253         }
 254       else
 255         {
 256           struct line_map *map = &set->maps[set->used - 1];
 257           r = linemap_line_start (set, SOURCE_LINE (map, r), to_column + 50);
 258         }
 259     }
 260   r = r + to_column;
 261   if (r >= set->highest_location)
 262     set->highest_location = r;
 263   return r;
 264 }
 265
 266 /* Given a logical line, returns the map from which the corresponding
 267    (source file, line) pair can be deduced.  Since the set is built
 268    chronologically, the logical lines are monotonic increasing, and so
 269    the list is sorted and we can use a binary search.  */
 270
 271 const struct line_map *
 272 linemap_lookup (struct line_maps *set, source_location line)
 273 {
 274   unsigned int md, mn, mx;
 275   const struct line_map *cached;
 276
 277   mn = set->cache;
 278   mx = set->used;
 279
 280   cached = &set->maps[mn];
 281   /* We should get a segfault if no line_maps have been added yet.  */
 282   if (line >= cached->start_location)
 283     {
 284       if (mn + 1 == mx || line < cached[1].start_location)
 285         return cached;
 286     }
 287   else
 288     {
 289       mx = mn;
 290       mn = 0;
 291     }
 292
 293   while (mx - mn > 1)
 294     {
 295       md = (mn + mx) / 2;
 296       if (set->maps[md].start_location > line)
 297         mx = md;
 298       else
 299         mn = md;
 300     }
 301
 302   set->cache = mn;
 303   return &set->maps[mn];
 304 }
 305
 306 /* Print an include trace, for e.g. the -H option of the preprocessor.  */
 307
 308 static void
 309 trace_include (const struct line_maps *set, const struct line_map *map)
 310 {
 311   unsigned int i = set->depth;
 312
 313   while (--i)
 314     putc ('.', stderr);
 315   fprintf (stderr, " %s\n", map->to_file);
 316 }