libcpp/line-map.c

   1 /* Map logical line numbers to (source file, line number) pairs.
   2    Copyright (C) 2001, 2003, 2004, 2007, 2008
   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 }
  45
  46 /* Check for and warn about line_maps entered but not exited.  */
  47
  48 void
  49 linemap_check_files_exited (struct line_maps *set)
  50 {
  51   struct line_map *map;
  52   /* Depending upon whether we are handling preprocessed input or
  53      not, this can be a user error or an ICE.  */
  54   for (map = &set->maps[set->used - 1]; ! MAIN_FILE_P (map);
  55        map = INCLUDED_FROM (set, map))
  56     fprintf (stderr, "line-map.c: file \"%s\" entered but not left\n",
  57              map->to_file);
  58 }
  59
  60 /* Free a line map set.  */
  61
  62 void
  63 linemap_free (struct line_maps *set)
  64 {
  65   if (set->maps)
  66     {
  67       linemap_check_files_exited (set);
  68
  69       free (set->maps);
  70     }
  71 }
  72
  73 /* Add a mapping of logical source line to physical source file and
  74    line number.
  75
  76    The text pointed to by TO_FILE must have a lifetime
  77    at least as long as the final call to lookup_line ().  An empty
  78    TO_FILE means standard input.  If reason is LC_LEAVE, and
  79    TO_FILE is NULL, then TO_FILE, TO_LINE and SYSP are given their
  80    natural values considering the file we are returning to.
  81
  82    FROM_LINE should be monotonic increasing across calls to this
  83    function.  A call to this function can relocate the previous set of
  84    maps, so any stored line_map pointers should not be used.  */
  85
  86 const struct line_map *
  87 linemap_add (struct line_maps *set, enum lc_reason reason,
  88              unsigned int sysp, const char *to_file, linenum_type to_line)
  89 {
  90   struct line_map *map;
  91   source_location start_location = set->highest_location + 1;
  92
  93   if (set->used && start_location < set->maps[set->used - 1].start_location)
  94     abort ();
  95
  96   if (set->used == set->allocated)
  97     {
  98       line_map_realloc reallocator
  99         = set->reallocator ? set->reallocator : xrealloc;
 100       set->allocated = 2 * set->allocated + 256;
 101       set->maps
 102         = (struct line_map *) (*reallocator) (set->maps,
 103                                               set->allocated
 104                                               * sizeof (struct line_map));
 105       memset (&set->maps[set->used], 0, ((set->allocated - set->used)
 106                                          * sizeof (struct line_map)));
 107     }
 108
 109   map = &set->maps[set->used];
 110
 111   if (to_file && *to_file == '\0')
 112     to_file = "<stdin>";
 113
 114   /* If we don't keep our line maps consistent, we can easily
 115      segfault.  Don't rely on the client to do it for us.  */
 116   if (set->depth == 0)
 117     reason = LC_ENTER;
 118   else if (reason == LC_LEAVE)
 119     {
 120       struct line_map *from;
 121       bool error;
 122
 123       if (MAIN_FILE_P (map - 1))
 124         {
 125           if (to_file == NULL)
 126             {
 127               set->depth--;
 128               return NULL;
 129             }
 130           error = true;
 131           reason = LC_RENAME;
 132           from = map - 1;
 133         }
 134       else
 135         {
 136           from = INCLUDED_FROM (set, map - 1);
 137           error = to_file && strcmp (from->to_file, to_file);
 138         }
 139
 140       /* Depending upon whether we are handling preprocessed input or
 141          not, this can be a user error or an ICE.  */
 142       if (error)
 143         fprintf (stderr, "line-map.c: file \"%s\" left but not entered\n",
 144                  to_file);
 145
 146       /* A TO_FILE of NULL is special - we use the natural values.  */
 147       if (error || to_file == NULL)
 148         {
 149           to_file = from->to_file;
 150           to_line = SOURCE_LINE (from, from[1].start_location);
 151           sysp = from->sysp;
 152         }
 153     }
 154
 155   map->reason = reason;
 156   map->sysp = sysp;
 157   map->start_location = start_location;
 158   map->to_file = to_file;
 159   map->to_line = to_line;
 160   set->cache = set->used++;
 161   map->column_bits = 0;
 162   set->highest_location = start_location;
 163   set->highest_line = start_location;
 164   set->max_column_hint = 0;
 165
 166   if (reason == LC_ENTER)
 167     {
 168       map->included_from = set->depth == 0 ? -1 : (int) (set->used - 2);
 169       set->depth++;
 170       if (set->trace_includes)
 171         trace_include (set, map);
 172     }
 173   else if (reason == LC_RENAME)
 174     map->included_from = map[-1].included_from;
 175   else if (reason == LC_LEAVE)
 176     {
 177       set->depth--;
 178       map->included_from = INCLUDED_FROM (set, map - 1)->included_from;
 179     }
 180
 181   return map;
 182 }
 183
 184 source_location
 185 linemap_line_start (struct line_maps *set, linenum_type to_line,
 186                     unsigned int max_column_hint)
 187 {
 188   struct line_map *map = &set->maps[set->used - 1];
 189   source_location highest = set->highest_location;
 190   source_location r;
 191   linenum_type last_line = SOURCE_LINE (map, set->highest_line);
 192   int line_delta = to_line - last_line;
 193   bool add_map = false;
 194   if (line_delta < 0
 195       || (line_delta > 10 && line_delta * map->column_bits > 1000)
 196       || (max_column_hint >= (1U << map->column_bits))
 197       || (max_column_hint <= 80 && map->column_bits >= 10))
 198     {
 199       add_map = true;
 200     }
 201   else
 202     max_column_hint = set->max_column_hint;
 203   if (add_map)
 204     {
 205       int column_bits;
 206       if (max_column_hint > 100000 || highest > 0xC0000000)
 207         {
 208           /* If the column number is ridiculous or we've allocated a huge
 209              number of source_locations, give up on column numbers. */
 210           max_column_hint = 0;
 211           if (highest >0xF0000000)
 212             return 0;
 213           column_bits = 0;
 214         }
 215       else
 216         {
 217           column_bits = 7;
 218           while (max_column_hint >= (1U << column_bits))
 219             column_bits++;
 220           max_column_hint = 1U << column_bits;
 221         }
 222       /* Allocate the new line_map.  However, if the current map only has a
 223          single line we can sometimes just increase its column_bits instead. */
 224       if (line_delta < 0
 225           || last_line != map->to_line
 226           || SOURCE_COLUMN (map, highest) >= (1U << column_bits))
 227         map = (struct line_map *) linemap_add (set, LC_RENAME, map->sysp,
 228                                                map->to_file, to_line);
 229       map->column_bits = column_bits;
 230       r = map->start_location + ((to_line - map->to_line) << column_bits);
 231     }
 232   else
 233     r = highest - SOURCE_COLUMN (map, highest)
 234       + (line_delta << map->column_bits);
 235   set->highest_line = r;
 236   if (r > set->highest_location)
 237     set->highest_location = r;
 238   set->max_column_hint = max_column_hint;
 239   return r;
 240 }
 241
 242 source_location
 243 linemap_position_for_column (struct line_maps *set, unsigned int to_column)
 244 {
 245   source_location r = set->highest_line;
 246   if (to_column >= set->max_column_hint)
 247     {
 248       if (r >= 0xC000000 || to_column > 100000)
 249         {
 250           /* Running low on source_locations - disable column numbers.  */
 251           return r;
 252         }
 253       else
 254         {
 255           struct line_map *map = &set->maps[set->used - 1];
 256           r = linemap_line_start (set, SOURCE_LINE (map, r), to_column + 50);
 257         }
 258     }
 259   r = r + to_column;
 260   if (r >= set->highest_location)
 261     set->highest_location = r;
 262   return r;
 263 }
 264
 265 /* Given a logical line, returns the map from which the corresponding
 266    (source file, line) pair can be deduced.  Since the set is built
 267    chronologically, the logical lines are monotonic increasing, and so
 268    the list is sorted and we can use a binary search.  */
 269
 270 const struct line_map *
 271 linemap_lookup (struct line_maps *set, source_location line)
 272 {
 273   unsigned int md, mn, mx;
 274   const struct line_map *cached;
 275
 276   mn = set->cache;
 277   mx = set->used;
 278
 279   cached = &set->maps[mn];
 280   /* We should get a segfault if no line_maps have been added yet.  */
 281   if (line >= cached->start_location)
 282     {
 283       if (mn + 1 == mx || line < cached[1].start_location)
 284         return cached;
 285     }
 286   else
 287     {
 288       mx = mn;
 289       mn = 0;
 290     }
 291
 292   while (mx - mn > 1)
 293     {
 294       md = (mn + mx) / 2;
 295       if (set->maps[md].start_location > line)
 296         mx = md;
 297       else
 298         mn = md;
 299     }
 300
 301   set->cache = mn;
 302   return &set->maps[mn];
 303 }
 304
 305 /* Print the file names and line numbers of the #include commands
 306    which led to the map MAP, if any, to stderr.  Nothing is output if
 307    the most recently listed stack is the same as the current one.  */
 308
 309 void
 310 linemap_print_containing_files (struct line_maps *set,
 311                                 const struct line_map *map)
 312 {
 313   if (MAIN_FILE_P (map) || set->last_listed == map->included_from)
 314     return;
 315
 316   set->last_listed = map->included_from;
 317   map = INCLUDED_FROM (set, map);
 318
 319   fprintf (stderr,  _("In file included from %s:%u"),
 320            map->to_file, LAST_SOURCE_LINE (map));
 321
 322   while (! MAIN_FILE_P (map))
 323     {
 324       map = INCLUDED_FROM (set, map);
 325       /* Translators note: this message is used in conjunction
 326          with "In file included from %s:%ld" and some other
 327          tricks.  We want something like this:
 328
 329          | In file included from sys/select.h:123,
 330          |                  from sys/types.h:234,
 331          |                  from userfile.c:31:
 332          | bits/select.h:45: <error message here>
 333
 334          with all the "from"s lined up.
 335          The trailing comma is at the beginning of this message,
 336          and the trailing colon is not translated.  */
 337       fprintf (stderr, _(",\n                 from %s:%u"),
 338                map->to_file, LAST_SOURCE_LINE (map));
 339     }
 340
 341   fputs (":\n", stderr);
 342 }
 343
 344 /* Print an include trace, for e.g. the -H option of the preprocessor.  */
 345
 346 static void
 347 trace_include (const struct line_maps *set, const struct line_map *map)
 348 {
 349   unsigned int i = set->depth;
 350
 351   while (--i)
 352     putc ('.', stderr);
 353   fprintf (stderr, " %s\n", map->to_file);
 354 }