libcpp/line-map.c

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