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 3, 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; see the file COPYING3.  If not see
  17 <http://www.gnu.org/licenses/>.
  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->trace_includes = false;
  38   set->depth = 0;
  39   set->cache = 0;
  40   set->highest_location = RESERVED_LOCATION_COUNT - 1;
  41   set->highest_line = RESERVED_LOCATION_COUNT - 1;
  42   set->max_column_hint = 0;
  43   set->reallocator = 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' && reason != LC_RENAME_VERBATIM)
 112     to_file = "<stdin>";
 113
 114   if (reason == LC_RENAME_VERBATIM)
 115     reason = LC_RENAME;
 116
 117   if (set->depth == 0 && reason == LC_RENAME)
 118     abort ();
 119
 120   if (reason == LC_LEAVE)
 121     {
 122       struct line_map *from;
 123       bool error;
 124
 125       if (MAIN_FILE_P (map - 1))
 126         {
 127           if (to_file == NULL)
 128             {
 129               set->depth--;
 130               return NULL;
 131             }
 132           error = true;
 133           reason = LC_RENAME;
 134           from = map - 1;
 135         }
 136       else
 137         {
 138           from = INCLUDED_FROM (set, map - 1);
 139           error = to_file && filename_cmp (from->to_file, to_file);
 140         }
 141
 142       /* Depending upon whether we are handling preprocessed input or
 143          not, this can be a user error or an ICE.  */
 144       if (error)
 145         fprintf (stderr, "line-map.c: file \"%s\" left but not entered\n",
 146                  to_file);
 147
 148       /* A TO_FILE of NULL is special - we use the natural values.  */
 149       if (error || to_file == NULL)
 150         {
 151           to_file = from->to_file;
 152           to_line = SOURCE_LINE (from, from[1].start_location);
 153           sysp = from->sysp;
 154         }
 155     }
 156
 157   map->reason = reason;
 158   map->sysp = sysp;
 159   map->start_location = start_location;
 160   map->to_file = to_file;
 161   map->to_line = to_line;
 162   set->cache = set->used++;
 163   map->column_bits = 0;
 164   set->highest_location = start_location;
 165   set->highest_line = start_location;
 166   set->max_column_hint = 0;
 167
 168   if (reason == LC_ENTER)
 169     {
 170       map->included_from = set->depth == 0 ? -1 : (int) (set->used - 2);
 171       set->depth++;
 172       if (set->trace_includes)
 173         trace_include (set, map);
 174     }
 175   else if (reason == LC_RENAME)
 176     map->included_from = map[-1].included_from;
 177   else if (reason == LC_LEAVE)
 178     {
 179       set->depth--;
 180       map->included_from = INCLUDED_FROM (set, map - 1)->included_from;
 181     }
 182
 183   return map;
 184 }
 185
 186 source_location
 187 linemap_line_start (struct line_maps *set, linenum_type to_line,
 188                     unsigned int max_column_hint)
 189 {
 190   struct line_map *map = &set->maps[set->used - 1];
 191   source_location highest = set->highest_location;
 192   source_location r;
 193   linenum_type last_line = SOURCE_LINE (map, set->highest_line);
 194   int line_delta = to_line - last_line;
 195   bool add_map = false;
 196   if (line_delta < 0
 197       || (line_delta > 10 && line_delta * map->column_bits > 1000)
 198       || (max_column_hint >= (1U << map->column_bits))
 199       || (max_column_hint <= 80 && map->column_bits >= 10))
 200     {
 201       add_map = true;
 202     }
 203   else
 204     max_column_hint = set->max_column_hint;
 205   if (add_map)
 206     {
 207       int column_bits;
 208       if (max_column_hint > 100000 || highest > 0xC0000000)
 209         {
 210           /* If the column number is ridiculous or we've allocated a huge
 211              number of source_locations, give up on column numbers. */
 212           max_column_hint = 0;
 213           if (highest >0xF0000000)
 214             return 0;
 215           column_bits = 0;
 216         }
 217       else
 218         {
 219           column_bits = 7;
 220           while (max_column_hint >= (1U << column_bits))
 221             column_bits++;
 222           max_column_hint = 1U << column_bits;
 223         }
 224       /* Allocate the new line_map.  However, if the current map only has a
 225          single line we can sometimes just increase its column_bits instead. */
 226       if (line_delta < 0
 227           || last_line != map->to_line
 228           || SOURCE_COLUMN (map, highest) >= (1U << column_bits))
 229         map = (struct line_map *) linemap_add (set, LC_RENAME, map->sysp,
 230                                                map->to_file, to_line);
 231       map->column_bits = column_bits;
 232       r = map->start_location + ((to_line - map->to_line) << column_bits);
 233     }
 234   else
 235     r = highest - SOURCE_COLUMN (map, highest)
 236       + (line_delta << map->column_bits);
 237   set->highest_line = r;
 238   if (r > set->highest_location)
 239     set->highest_location = r;
 240   set->max_column_hint = max_column_hint;
 241   return r;
 242 }
 243
 244 source_location
 245 linemap_position_for_column (struct line_maps *set, unsigned int to_column)
 246 {
 247   source_location r = set->highest_line;
 248   if (to_column >= set->max_column_hint)
 249     {
 250       if (r >= 0xC000000 || to_column > 100000)
 251         {
 252           /* Running low on source_locations - disable column numbers.  */
 253           return r;
 254         }
 255       else
 256         {
 257           struct line_map *map = &set->maps[set->used - 1];
 258           r = linemap_line_start (set, SOURCE_LINE (map, r), to_column + 50);
 259         }
 260     }
 261   r = r + to_column;
 262   if (r >= set->highest_location)
 263     set->highest_location = r;
 264   return r;
 265 }
 266
 267 /* Given a logical line, returns the map from which the corresponding
 268    (source file, line) pair can be deduced.  Since the set is built
 269    chronologically, the logical lines are monotonic increasing, and so
 270    the list is sorted and we can use a binary search.  */
 271
 272 const struct line_map *
 273 linemap_lookup (struct line_maps *set, source_location line)
 274 {
 275   unsigned int md, mn, mx;
 276   const struct line_map *cached;
 277
 278   mn = set->cache;
 279   mx = set->used;
 280
 281   cached = &set->maps[mn];
 282   /* We should get a segfault if no line_maps have been added yet.  */
 283   if (line >= cached->start_location)
 284     {
 285       if (mn + 1 == mx || line < cached[1].start_location)
 286         return cached;
 287     }
 288   else
 289     {
 290       mx = mn;
 291       mn = 0;
 292     }
 293
 294   while (mx - mn > 1)
 295     {
 296       md = (mn + mx) / 2;
 297       if (set->maps[md].start_location > line)
 298         mx = md;
 299       else
 300         mn = md;
 301     }
 302
 303   set->cache = mn;
 304   return &set->maps[mn];
 305 }
 306
 307 /* Print an include trace, for e.g. the -H option of the preprocessor.  */
 308
 309 static void
 310 trace_include (const struct line_maps *set, const struct line_map *map)
 311 {
 312   unsigned int i = set->depth;
 313
 314   while (--i)
 315     putc ('.', stderr);
 316   fprintf (stderr, " %s\n", map->to_file);
 317 }