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->last_listed = -1;
  38   set->trace_includes = false;
  39   set->depth = 0;
  40   set->cache = 0;
  41   set->highest_location = RESERVED_LOCATION_COUNT - 1;
  42   set->highest_line = RESERVED_LOCATION_COUNT - 1;
  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' && reason != LC_RENAME_VERBATIM)
 113     to_file = "<stdin>";
 114
 115   if (reason == LC_RENAME_VERBATIM)
 116     reason = LC_RENAME;
 117
 118   /* If we don't keep our line maps consistent, we can easily
 119      segfault.  Don't rely on the client to do it for us.  */
 120   if (set->depth == 0)
 121     reason = LC_ENTER;
 122   else if (reason == LC_LEAVE)
 123     {
 124       struct line_map *from;
 125       bool error;
 126
 127       if (MAIN_FILE_P (map - 1))
 128         {
 129           if (to_file == NULL)
 130             {
 131               set->depth--;
 132               return NULL;
 133             }
 134           error = true;
 135           reason = LC_RENAME;
 136           from = map - 1;
 137         }
 138       else
 139         {
 140           from = INCLUDED_FROM (set, map - 1);
 141           error = to_file && strcmp (from->to_file, to_file);
 142         }
 143
 144       /* Depending upon whether we are handling preprocessed input or
 145          not, this can be a user error or an ICE.  */
 146       if (error)
 147         fprintf (stderr, "line-map.c: file \"%s\" left but not entered\n",
 148                  to_file);
 149
 150       /* A TO_FILE of NULL is special - we use the natural values.  */
 151       if (error || to_file == NULL)
 152         {
 153           to_file = from->to_file;
 154           to_line = SOURCE_LINE (from, from[1].start_location);
 155           sysp = from->sysp;
 156         }
 157     }
 158
 159   map->reason = reason;
 160   map->sysp = sysp;
 161   map->start_location = start_location;
 162   map->to_file = to_file;
 163   map->to_line = to_line;
 164   set->cache = set->used++;
 165   map->column_bits = 0;
 166   set->highest_location = start_location;
 167   set->highest_line = start_location;
 168   set->max_column_hint = 0;
 169
 170   if (reason == LC_ENTER)
 171     {
 172       map->included_from = set->depth == 0 ? -1 : (int) (set->used - 2);
 173       set->depth++;
 174       if (set->trace_includes)
 175         trace_include (set, map);
 176     }
 177   else if (reason == LC_RENAME)
 178     map->included_from = map[-1].included_from;
 179   else if (reason == LC_LEAVE)
 180     {
 181       set->depth--;
 182       map->included_from = INCLUDED_FROM (set, map - 1)->included_from;
 183     }
 184
 185   return map;
 186 }
 187
 188 source_location
 189 linemap_line_start (struct line_maps *set, linenum_type to_line,
 190                     unsigned int max_column_hint)
 191 {
 192   struct line_map *map = &set->maps[set->used - 1];
 193   source_location highest = set->highest_location;
 194   source_location r;
 195   linenum_type last_line = SOURCE_LINE (map, set->highest_line);
 196   int line_delta = to_line - last_line;
 197   bool add_map = false;
 198   if (line_delta < 0
 199       || (line_delta > 10 && line_delta * map->column_bits > 1000)
 200       || (max_column_hint >= (1U << map->column_bits))
 201       || (max_column_hint <= 80 && map->column_bits >= 10))
 202     {
 203       add_map = true;
 204     }
 205   else
 206     max_column_hint = set->max_column_hint;
 207   if (add_map)
 208     {
 209       int column_bits;
 210       if (max_column_hint > 100000 || highest > 0xC0000000)
 211         {
 212           /* If the column number is ridiculous or we've allocated a huge
 213              number of source_locations, give up on column numbers. */
 214           max_column_hint = 0;
 215           if (highest >0xF0000000)
 216             return 0;
 217           column_bits = 0;
 218         }
 219       else
 220         {
 221           column_bits = 7;
 222           while (max_column_hint >= (1U << column_bits))
 223             column_bits++;
 224           max_column_hint = 1U << column_bits;
 225         }
 226       /* Allocate the new line_map.  However, if the current map only has a
 227          single line we can sometimes just increase its column_bits instead. */
 228       if (line_delta < 0
 229           || last_line != map->to_line
 230           || SOURCE_COLUMN (map, highest) >= (1U << column_bits))
 231         map = (struct line_map *) linemap_add (set, LC_RENAME, map->sysp,
 232                                                map->to_file, to_line);
 233       map->column_bits = column_bits;
 234       r = map->start_location + ((to_line - map->to_line) << column_bits);
 235     }
 236   else
 237     r = highest - SOURCE_COLUMN (map, highest)
 238       + (line_delta << map->column_bits);
 239   set->highest_line = r;
 240   if (r > set->highest_location)
 241     set->highest_location = r;
 242   set->max_column_hint = max_column_hint;
 243   return r;
 244 }
 245
 246 source_location
 247 linemap_position_for_column (struct line_maps *set, unsigned int to_column)
 248 {
 249   source_location r = set->highest_line;
 250   if (to_column >= set->max_column_hint)
 251     {
 252       if (r >= 0xC000000 || to_column > 100000)
 253         {
 254           /* Running low on source_locations - disable column numbers.  */
 255           return r;
 256         }
 257       else
 258         {
 259           struct line_map *map = &set->maps[set->used - 1];
 260           r = linemap_line_start (set, SOURCE_LINE (map, r), to_column + 50);
 261         }
 262     }
 263   r = r + to_column;
 264   if (r >= set->highest_location)
 265     set->highest_location = r;
 266   return r;
 267 }
 268
 269 /* Given a logical line, returns the map from which the corresponding
 270    (source file, line) pair can be deduced.  Since the set is built
 271    chronologically, the logical lines are monotonic increasing, and so
 272    the list is sorted and we can use a binary search.  */
 273
 274 const struct line_map *
 275 linemap_lookup (struct line_maps *set, source_location line)
 276 {
 277   unsigned int md, mn, mx;
 278   const struct line_map *cached;
 279
 280   mn = set->cache;
 281   mx = set->used;
 282
 283   cached = &set->maps[mn];
 284   /* We should get a segfault if no line_maps have been added yet.  */
 285   if (line >= cached->start_location)
 286     {
 287       if (mn + 1 == mx || line < cached[1].start_location)
 288         return cached;
 289     }
 290   else
 291     {
 292       mx = mn;
 293       mn = 0;
 294     }
 295
 296   while (mx - mn > 1)
 297     {
 298       md = (mn + mx) / 2;
 299       if (set->maps[md].start_location > line)
 300         mx = md;
 301       else
 302         mn = md;
 303     }
 304
 305   set->cache = mn;
 306   return &set->maps[mn];
 307 }
 308
 309 /* Print an include trace, for e.g. the -H option of the preprocessor.  */
 310
 311 static void
 312 trace_include (const struct line_maps *set, const struct line_map *map)
 313 {
 314   unsigned int i = set->depth;
 315
 316   while (--i)
 317     putc ('.', stderr);
 318   fprintf (stderr, " %s\n", map->to_file);
 319 }