libcpp/directives-only.c

   1 /* CPP Library - directive only preprocessing for distributed compilation.
   2    Copyright (C) 2007, 2009
   3    Free Software Foundation, Inc.
   4    Contributed by Ollie Wild <aaw@google.com>.
   5
   6 This program is free software; you can redistribute it and/or modify it
   7 under the terms of the GNU General Public License as published by the
   8 Free Software Foundation; either version 3, or (at your option) any
   9 later version.
  10
  11 This program is distributed in the hope that it will be useful,
  12 but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 GNU General Public License for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with this program; see the file COPYING3.  If not see
  18 <http://www.gnu.org/licenses/>.  */
  19
  20 #include "config.h"
  21 #include "system.h"
  22 #include "cpplib.h"
  23 #include "internal.h"
  24
  25 /* DO (Directive only) flags. */
  26 #define DO_BOL           (1 << 0) /* At the beginning of a logical line. */
  27 #define DO_STRING        (1 << 1) /* In a string constant. */
  28 #define DO_CHAR          (1 << 2) /* In a character constant. */
  29 #define DO_BLOCK_COMMENT (1 << 3) /* In a block comment. */
  30 #define DO_LINE_COMMENT  (1 << 4) /* In a single line "//-style" comment. */
  31
  32 #define DO_LINE_SPECIAL (DO_STRING | DO_CHAR | DO_LINE_COMMENT)
  33 #define DO_SPECIAL      (DO_LINE_SPECIAL | DO_BLOCK_COMMENT)
  34
  35 /* Writes out the preprocessed file, handling spacing and paste
  36    avoidance issues.  */
  37 void
  38 _cpp_preprocess_dir_only (cpp_reader *pfile,
  39                           const struct _cpp_dir_only_callbacks *cb)
  40 {
  41   struct cpp_buffer *buffer;
  42   const unsigned char *cur, *base, *next_line, *rlimit;
  43   cppchar_t c, last_c;
  44   unsigned flags;
  45   linenum_type lines;
  46   int col;
  47   source_location loc;
  48
  49  restart:
  50   /* Buffer initialization ala _cpp_clean_line(). */
  51   buffer = pfile->buffer;
  52   buffer->cur_note = buffer->notes_used = 0;
  53   buffer->cur = buffer->line_base = buffer->next_line;
  54   buffer->need_line = false;
  55
  56   /* This isn't really needed.  It prevents a compiler warning, though. */
  57   loc = pfile->line_table->highest_line;
  58
  59   /* Scan initialization. */
  60   next_line = cur = base = buffer->cur;
  61   rlimit = buffer->rlimit;
  62   flags = DO_BOL;
  63   lines = 0;
  64   col = 1;
  65
  66   for (last_c = '\n', c = *cur; cur < rlimit; last_c = c, c = *++cur, ++col)
  67     {
  68       /* Skip over escaped newlines. */
  69       if (__builtin_expect (c == '\\', false))
  70         {
  71           const unsigned char *tmp = cur + 1;
  72
  73           while (is_nvspace (*tmp) && tmp < rlimit)
  74             tmp++;
  75           if (*tmp == '\r')
  76             tmp++;
  77           if (*tmp == '\n' && tmp < rlimit)
  78             {
  79               CPP_INCREMENT_LINE (pfile, 0);
  80               lines++;
  81               col = 0;
  82               cur = tmp;
  83               c = last_c;
  84               continue;
  85             }
  86         }
  87
  88       if (__builtin_expect (last_c == '#', false) && !(flags & DO_SPECIAL))
  89         {
  90           if (c != '#' && (flags & DO_BOL))
  91           {
  92             struct line_maps *line_table;
  93
  94             if (!pfile->state.skipping && next_line != base)
  95               cb->print_lines (lines, base, next_line - base);
  96
  97             /* Prep things for directive handling. */
  98             buffer->next_line = cur;
  99             buffer->need_line = true;
 100             _cpp_get_fresh_line (pfile);
 101
 102             /* Ensure proper column numbering for generated error messages. */
 103             buffer->line_base -= col - 1;
 104
 105             _cpp_handle_directive (pfile, 0 /* ignore indented */);
 106
 107             /* Sanitize the line settings.  Duplicate #include's can mess
 108                things up. */
 109             line_table = pfile->line_table;
 110             line_table->highest_location = line_table->highest_line;
 111
 112             /* The if block prevents us from outputing line information when
 113                the file ends with a directive and no newline.  Note that we
 114                must use pfile->buffer, not buffer. */
 115             if (pfile->buffer->next_line < pfile->buffer->rlimit)
 116               cb->maybe_print_line (pfile->line_table->highest_line);
 117
 118             goto restart;
 119           }
 120
 121           flags &= ~DO_BOL;
 122           pfile->mi_valid = false;
 123         }
 124       else if (__builtin_expect (last_c == '/', false) \
 125                && !(flags & DO_SPECIAL) && c != '*' && c != '/')
 126         {
 127           /* If a previous slash is not starting a block comment, clear the
 128              DO_BOL flag.  */
 129           flags &= ~DO_BOL;
 130           pfile->mi_valid = false;
 131         }
 132
 133       switch (c)
 134         {
 135         case '/':
 136           if ((flags & DO_BLOCK_COMMENT) && last_c == '*')
 137             {
 138               flags &= ~DO_BLOCK_COMMENT;
 139               c = 0;
 140             }
 141           else if (!(flags & DO_SPECIAL) && last_c == '/')
 142             flags |= DO_LINE_COMMENT;
 143           else if (!(flags & DO_SPECIAL))
 144             /* Mark the position for possible error reporting. */
 145             LINEMAP_POSITION_FOR_COLUMN (loc, pfile->line_table, col);
 146
 147           break;
 148
 149         case '*':
 150           if (!(flags & DO_SPECIAL))
 151             {
 152               if (last_c == '/')
 153                 flags |= DO_BLOCK_COMMENT;
 154               else
 155                 {
 156                   flags &= ~DO_BOL;
 157                   pfile->mi_valid = false;
 158                 }
 159             }
 160
 161           break;
 162
 163         case '\'':
 164         case '"':
 165           {
 166             unsigned state = (c == '"') ? DO_STRING : DO_CHAR;
 167
 168             if (!(flags & DO_SPECIAL))
 169               {
 170                 flags |= state;
 171                 flags &= ~DO_BOL;
 172                 pfile->mi_valid = false;
 173               }
 174             else if ((flags & state) && last_c != '\\')
 175               flags &= ~state;
 176
 177             break;
 178           }
 179
 180         case '\\':
 181           {
 182             if ((flags & (DO_STRING | DO_CHAR)) && last_c == '\\')
 183               c = 0;
 184
 185             if (!(flags & DO_SPECIAL))
 186               {
 187                 flags &= ~DO_BOL;
 188                 pfile->mi_valid = false;
 189               }
 190
 191             break;
 192           }
 193
 194         case '\n':
 195           CPP_INCREMENT_LINE (pfile, 0);
 196           lines++;
 197           col = 0;
 198           flags &= ~DO_LINE_SPECIAL;
 199           if (!(flags & DO_SPECIAL))
 200             flags |= DO_BOL;
 201           break;
 202
 203         case '#':
 204           next_line = cur;
 205           /* Don't update DO_BOL yet. */
 206           break;
 207
 208         case ' ': case '\t': case '\f': case '\v': case '\0':
 209           break;
 210
 211         default:
 212           if (!(flags & DO_SPECIAL))
 213             {
 214               flags &= ~DO_BOL;
 215               pfile->mi_valid = false;
 216             }
 217           break;
 218         }
 219     }
 220
 221   if (flags & DO_BLOCK_COMMENT)
 222     cpp_error_with_line (pfile, CPP_DL_ERROR, loc, 0, "unterminated comment");
 223
 224   if (!pfile->state.skipping && cur != base)
 225     {
 226       /* If the file was not newline terminated, add rlimit, which is
 227          guaranteed to point to a newline, to the end of our range.  */
 228       if (cur[-1] != '\n')
 229         {
 230           cur++;
 231           CPP_INCREMENT_LINE (pfile, 0);
 232           lines++;
 233         }
 234
 235       cb->print_lines (lines, base, cur - base);
 236     }
 237
 238   _cpp_pop_buffer (pfile);
 239   if (pfile->buffer)
 240     goto restart;
 241 }