gcc/cppinit.c

   1 /* CPP Library.
   2    Copyright (C) 1986, 1987, 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
   3    1999, 2000, 2001, 2002, 2003, 2004 Free Software Foundation, Inc.
   4    Contributed by Per Bothner, 1994-95.
   5    Based on CCCP program by Paul Rubin, June 1986
   6    Adapted to ANSI C, Richard Stallman, Jan 1987
   7
   8 This program is free software; you can redistribute it and/or modify it
   9 under the terms of the GNU General Public License as published by the
  10 Free Software Foundation; either version 2, or (at your option) any
  11 later version.
  12
  13 This program is distributed in the hope that it will be useful,
  14 but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16 GNU General Public License for more details.
  17
  18 You should have received a copy of the GNU General Public License
  19 along with this program; if not, write to the Free Software
  20 Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
  21
  22 #include "config.h"
  23 #include "system.h"
  24 #include "cpplib.h"
  25 #include "cpphash.h"
  26 #include "mkdeps.h"
  27
  28 static void init_library (void);
  29 static void mark_named_operators (cpp_reader *);
  30 static void read_original_filename (cpp_reader *);
  31 static void read_original_directory (cpp_reader *);
  32 static void post_options (cpp_reader *);
  33
  34 /* If we have designated initializers (GCC >2.7) these tables can be
  35    initialized, constant data.  Otherwise, they have to be filled in at
  36    runtime.  */
  37 #if HAVE_DESIGNATED_INITIALIZERS
  38
  39 #define init_trigraph_map()  /* Nothing.  */
  40 #define TRIGRAPH_MAP \
  41 __extension__ const uchar _cpp_trigraph_map[UCHAR_MAX + 1] = {
  42
  43 #define END };
  44 #define s(p, v) [p] = v,
  45
  46 #else
  47
  48 #define TRIGRAPH_MAP uchar _cpp_trigraph_map[UCHAR_MAX + 1] = { 0 }; \
  49  static void init_trigraph_map (void) { \
  50  unsigned char *x = _cpp_trigraph_map;
  51
  52 #define END }
  53 #define s(p, v) x[p] = v;
  54
  55 #endif
  56
  57 TRIGRAPH_MAP
  58   s('=', '#')   s(')', ']')     s('!', '|')
  59   s('(', '[')   s('\'', '^')    s('>', '}')
  60   s('/', '\\')  s('<', '{')     s('-', '~')
  61 END
  62
  63 #undef s
  64 #undef END
  65 #undef TRIGRAPH_MAP
  66
  67 /* A set of booleans indicating what CPP features each source language
  68    requires.  */
  69 struct lang_flags
  70 {
  71   char c99;
  72   char cplusplus;
  73   char extended_numbers;
  74   char std;
  75   char cplusplus_comments;
  76   char digraphs;
  77 };
  78
  79 static const struct lang_flags lang_defaults[] =
  80 { /*              c99 c++ xnum std  //   digr  */
  81   /* GNUC89 */  { 0,  0,  1,   0,   1,   1     },
  82   /* GNUC99 */  { 1,  0,  1,   0,   1,   1     },
  83   /* STDC89 */  { 0,  0,  0,   1,   0,   0     },
  84   /* STDC94 */  { 0,  0,  0,   1,   0,   1     },
  85   /* STDC99 */  { 1,  0,  1,   1,   1,   1     },
  86   /* GNUCXX */  { 0,  1,  1,   0,   1,   1     },
  87   /* CXX98  */  { 0,  1,  1,   1,   1,   1     },
  88   /* ASM    */  { 0,  0,  1,   0,   1,   0     }
  89 };
  90
  91 /* Sets internal flags correctly for a given language.  */
  92 void
  93 cpp_set_lang (cpp_reader *pfile, enum c_lang lang)
  94 {
  95   const struct lang_flags *l = &lang_defaults[(int) lang];
  96
  97   CPP_OPTION (pfile, lang) = lang;
  98
  99   CPP_OPTION (pfile, c99)                = l->c99;
 100   CPP_OPTION (pfile, cplusplus)          = l->cplusplus;
 101   CPP_OPTION (pfile, extended_numbers)   = l->extended_numbers;
 102   CPP_OPTION (pfile, std)                = l->std;
 103   CPP_OPTION (pfile, trigraphs)          = l->std;
 104   CPP_OPTION (pfile, cplusplus_comments) = l->cplusplus_comments;
 105   CPP_OPTION (pfile, digraphs)           = l->digraphs;
 106 }
 107
 108 /* Initialize library global state.  */
 109 static void
 110 init_library (void)
 111 {
 112   static int initialized = 0;
 113
 114   if (! initialized)
 115     {
 116       initialized = 1;
 117
 118       /* Set up the trigraph map.  This doesn't need to do anything if
 119          we were compiled with a compiler that supports C99 designated
 120          initializers.  */
 121       init_trigraph_map ();
 122     }
 123 }
 124
 125 /* Initialize a cpp_reader structure.  */
 126 cpp_reader *
 127 cpp_create_reader (enum c_lang lang, hash_table *table,
 128                    struct line_maps *line_table)
 129 {
 130   cpp_reader *pfile;
 131
 132   /* Initialize this instance of the library if it hasn't been already.  */
 133   init_library ();
 134
 135   pfile = xcalloc (1, sizeof (cpp_reader));
 136
 137   cpp_set_lang (pfile, lang);
 138   CPP_OPTION (pfile, warn_multichar) = 1;
 139   CPP_OPTION (pfile, discard_comments) = 1;
 140   CPP_OPTION (pfile, discard_comments_in_macro_exp) = 1;
 141   CPP_OPTION (pfile, show_column) = 1;
 142   CPP_OPTION (pfile, tabstop) = 8;
 143   CPP_OPTION (pfile, operator_names) = 1;
 144   CPP_OPTION (pfile, warn_trigraphs) = 2;
 145   CPP_OPTION (pfile, warn_endif_labels) = 1;
 146   CPP_OPTION (pfile, warn_deprecated) = 1;
 147   CPP_OPTION (pfile, warn_long_long) = !CPP_OPTION (pfile, c99);
 148   CPP_OPTION (pfile, dollars_in_ident) = 1;
 149   CPP_OPTION (pfile, warn_dollars) = 1;
 150   CPP_OPTION (pfile, warn_variadic_macros) = 1;
 151
 152   /* Default CPP arithmetic to something sensible for the host for the
 153      benefit of dumb users like fix-header.  */
 154   CPP_OPTION (pfile, precision) = CHAR_BIT * sizeof (long);
 155   CPP_OPTION (pfile, char_precision) = CHAR_BIT;
 156   CPP_OPTION (pfile, wchar_precision) = CHAR_BIT * sizeof (int);
 157   CPP_OPTION (pfile, int_precision) = CHAR_BIT * sizeof (int);
 158   CPP_OPTION (pfile, unsigned_char) = 0;
 159   CPP_OPTION (pfile, unsigned_wchar) = 1;
 160   CPP_OPTION (pfile, bytes_big_endian) = 1;  /* does not matter */
 161
 162   /* Default to no charset conversion.  */
 163   CPP_OPTION (pfile, narrow_charset) = _cpp_default_encoding ();
 164   CPP_OPTION (pfile, wide_charset) = 0;
 165
 166   /* Default the input character set to UTF-8.  */
 167   CPP_OPTION (pfile, input_charset) = _cpp_default_encoding ();
 168
 169   /* A fake empty "directory" used as the starting point for files
 170      looked up without a search path.  Name cannot be '/' because we
 171      don't want to prepend anything at all to filenames using it.  All
 172      other entries are correct zero-initialized.  */
 173   pfile->no_search_path.name = (char *) "";
 174
 175   /* Initialize the line map.  Start at logical line 1, so we can use
 176      a line number of zero for special states.  */
 177   pfile->line_table = line_table;
 178   pfile->line = 1;
 179
 180   /* Initialize lexer state.  */
 181   pfile->state.save_comments = ! CPP_OPTION (pfile, discard_comments);
 182
 183   /* Set up static tokens.  */
 184   pfile->avoid_paste.type = CPP_PADDING;
 185   pfile->avoid_paste.val.source = NULL;
 186   pfile->eof.type = CPP_EOF;
 187   pfile->eof.flags = 0;
 188
 189   /* Create a token buffer for the lexer.  */
 190   _cpp_init_tokenrun (&pfile->base_run, 250);
 191   pfile->cur_run = &pfile->base_run;
 192   pfile->cur_token = pfile->base_run.base;
 193
 194   /* Initialize the base context.  */
 195   pfile->context = &pfile->base_context;
 196   pfile->base_context.macro = 0;
 197   pfile->base_context.prev = pfile->base_context.next = 0;
 198
 199   /* Aligned and unaligned storage.  */
 200   pfile->a_buff = _cpp_get_buff (pfile, 0);
 201   pfile->u_buff = _cpp_get_buff (pfile, 0);
 202
 203   /* The expression parser stack.  */
 204   _cpp_expand_op_stack (pfile);
 205
 206   /* Initialize the buffer obstack.  */
 207   _obstack_begin (&pfile->buffer_ob, 0, 0,
 208                   (void *(*) (long)) xmalloc,
 209                   (void (*) (void *)) free);
 210
 211   _cpp_init_files (pfile);
 212
 213   _cpp_init_hashtable (pfile, table);
 214
 215   return pfile;
 216 }
 217
 218 /* Free resources used by PFILE.  Accessing PFILE after this function
 219    returns leads to undefined behavior.  Returns the error count.  */
 220 void
 221 cpp_destroy (cpp_reader *pfile)
 222 {
 223   cpp_context *context, *contextn;
 224   tokenrun *run, *runn;
 225
 226   free (pfile->op_stack);
 227
 228   while (CPP_BUFFER (pfile) != NULL)
 229     _cpp_pop_buffer (pfile);
 230
 231   if (pfile->out.base)
 232     free (pfile->out.base);
 233
 234   if (pfile->macro_buffer)
 235     {
 236       free (pfile->macro_buffer);
 237       pfile->macro_buffer = NULL;
 238       pfile->macro_buffer_len = 0;
 239     }
 240
 241   if (pfile->deps)
 242     deps_free (pfile->deps);
 243   obstack_free (&pfile->buffer_ob, 0);
 244
 245   _cpp_destroy_hashtable (pfile);
 246   _cpp_cleanup_files (pfile);
 247   _cpp_destroy_iconv (pfile);
 248
 249   _cpp_free_buff (pfile->a_buff);
 250   _cpp_free_buff (pfile->u_buff);
 251   _cpp_free_buff (pfile->free_buffs);
 252
 253   for (run = &pfile->base_run; run; run = runn)
 254     {
 255       runn = run->next;
 256       free (run->base);
 257       if (run != &pfile->base_run)
 258         free (run);
 259     }
 260
 261   for (context = pfile->base_context.next; context; context = contextn)
 262     {
 263       contextn = context->next;
 264       free (context);
 265     }
 266
 267   free (pfile);
 268 }
 269
 270 /* This structure defines one built-in identifier.  A node will be
 271    entered in the hash table under the name NAME, with value VALUE.
 272
 273    There are two tables of these.  builtin_array holds all the
 274    "builtin" macros: these are handled by builtin_macro() in
 275    cppmacro.c.  Builtin is somewhat of a misnomer -- the property of
 276    interest is that these macros require special code to compute their
 277    expansions.  The value is a "builtin_type" enumerator.
 278
 279    operator_array holds the C++ named operators.  These are keywords
 280    which act as aliases for punctuators.  In C++, they cannot be
 281    altered through #define, and #if recognizes them as operators.  In
 282    C, these are not entered into the hash table at all (but see
 283    <iso646.h>).  The value is a token-type enumerator.  */
 284 struct builtin
 285 {
 286   const uchar *name;
 287   unsigned short len;
 288   unsigned short value;
 289 };
 290
 291 #define B(n, t)    { DSC(n), t }
 292 static const struct builtin builtin_array[] =
 293 {
 294   B("__TIME__",          BT_TIME),
 295   B("__DATE__",          BT_DATE),
 296   B("__FILE__",          BT_FILE),
 297   B("__BASE_FILE__",     BT_BASE_FILE),
 298   B("__LINE__",          BT_SPECLINE),
 299   B("__INCLUDE_LEVEL__", BT_INCLUDE_LEVEL),
 300   /* Keep builtins not used for -traditional-cpp at the end, and
 301      update init_builtins() if any more are added.  */
 302   B("_Pragma",           BT_PRAGMA),
 303   B("__STDC__",          BT_STDC),
 304 };
 305
 306 static const struct builtin operator_array[] =
 307 {
 308   B("and",      CPP_AND_AND),
 309   B("and_eq",   CPP_AND_EQ),
 310   B("bitand",   CPP_AND),
 311   B("bitor",    CPP_OR),
 312   B("compl",    CPP_COMPL),
 313   B("not",      CPP_NOT),
 314   B("not_eq",   CPP_NOT_EQ),
 315   B("or",       CPP_OR_OR),
 316   B("or_eq",    CPP_OR_EQ),
 317   B("xor",      CPP_XOR),
 318   B("xor_eq",   CPP_XOR_EQ)
 319 };
 320 #undef B
 321
 322 /* Mark the C++ named operators in the hash table.  */
 323 static void
 324 mark_named_operators (cpp_reader *pfile)
 325 {
 326   const struct builtin *b;
 327
 328   for (b = operator_array;
 329        b < (operator_array + ARRAY_SIZE (operator_array));
 330        b++)
 331     {
 332       cpp_hashnode *hp = cpp_lookup (pfile, b->name, b->len);
 333       hp->flags |= NODE_OPERATOR;
 334       hp->is_directive = 0;
 335       hp->directive_index = b->value;
 336     }
 337 }
 338
 339 /* Read the builtins table above and enter them, and language-specific
 340    macros, into the hash table.  HOSTED is true if this is a hosted
 341    environment.  */
 342 void
 343 cpp_init_builtins (cpp_reader *pfile, int hosted)
 344 {
 345   const struct builtin *b;
 346   size_t n = ARRAY_SIZE (builtin_array);
 347
 348   if (CPP_OPTION (pfile, traditional))
 349     n -= 2;
 350
 351   for(b = builtin_array; b < builtin_array + n; b++)
 352     {
 353       cpp_hashnode *hp = cpp_lookup (pfile, b->name, b->len);
 354       hp->type = NT_MACRO;
 355       hp->flags |= NODE_BUILTIN | NODE_WARN;
 356       hp->value.builtin = b->value;
 357     }
 358
 359   if (CPP_OPTION (pfile, cplusplus))
 360     _cpp_define_builtin (pfile, "__cplusplus 1");
 361   else if (CPP_OPTION (pfile, lang) == CLK_ASM)
 362     _cpp_define_builtin (pfile, "__ASSEMBLER__ 1");
 363   else if (CPP_OPTION (pfile, lang) == CLK_STDC94)
 364     _cpp_define_builtin (pfile, "__STDC_VERSION__ 199409L");
 365   else if (CPP_OPTION (pfile, c99))
 366     _cpp_define_builtin (pfile, "__STDC_VERSION__ 199901L");
 367
 368   if (hosted)
 369     _cpp_define_builtin (pfile, "__STDC_HOSTED__ 1");
 370   else
 371     _cpp_define_builtin (pfile, "__STDC_HOSTED__ 0");
 372
 373   if (CPP_OPTION (pfile, objc))
 374     _cpp_define_builtin (pfile, "__OBJC__ 1");
 375 }
 376
 377 /* Sanity-checks are dependent on command-line options, so it is
 378    called as a subroutine of cpp_read_main_file ().  */
 379 #if ENABLE_CHECKING
 380 static void sanity_checks (cpp_reader *);
 381 static void sanity_checks (cpp_reader *pfile)
 382 {
 383   cppchar_t test = 0;
 384   size_t max_precision = 2 * CHAR_BIT * sizeof (cpp_num_part);
 385
 386   /* Sanity checks for assumptions about CPP arithmetic and target
 387      type precisions made by cpplib.  */
 388   test--;
 389   if (test < 1)
 390     cpp_error (pfile, CPP_DL_ICE, "cppchar_t must be an unsigned type");
 391
 392   if (CPP_OPTION (pfile, precision) > max_precision)
 393     cpp_error (pfile, CPP_DL_ICE,
 394                "preprocessor arithmetic has maximum precision of %lu bits;"
 395                " target requires %lu bits",
 396                (unsigned long) max_precision,
 397                (unsigned long) CPP_OPTION (pfile, precision));
 398
 399   if (CPP_OPTION (pfile, precision) < CPP_OPTION (pfile, int_precision))
 400     cpp_error (pfile, CPP_DL_ICE,
 401                "CPP arithmetic must be at least as precise as a target int");
 402
 403   if (CPP_OPTION (pfile, char_precision) < 8)
 404     cpp_error (pfile, CPP_DL_ICE, "target char is less than 8 bits wide");
 405
 406   if (CPP_OPTION (pfile, wchar_precision) < CPP_OPTION (pfile, char_precision))
 407     cpp_error (pfile, CPP_DL_ICE,
 408                "target wchar_t is narrower than target char");
 409
 410   if (CPP_OPTION (pfile, int_precision) < CPP_OPTION (pfile, char_precision))
 411     cpp_error (pfile, CPP_DL_ICE,
 412                "target int is narrower than target char");
 413
 414   /* This is assumed in eval_token() and could be fixed if necessary.  */
 415   if (sizeof (cppchar_t) > sizeof (cpp_num_part))
 416     cpp_error (pfile, CPP_DL_ICE,
 417                "CPP half-integer narrower than CPP character");
 418
 419   if (CPP_OPTION (pfile, wchar_precision) > BITS_PER_CPPCHAR_T)
 420     cpp_error (pfile, CPP_DL_ICE,
 421                "CPP on this host cannot handle wide character constants over"
 422                " %lu bits, but the target requires %lu bits",
 423                (unsigned long) BITS_PER_CPPCHAR_T,
 424                (unsigned long) CPP_OPTION (pfile, wchar_precision));
 425 }
 426 #else
 427 # define sanity_checks(PFILE)
 428 #endif
 429
 430 /* Add a dependency target.  Can be called any number of times before
 431    cpp_read_main_file().  If no targets have been added before
 432    cpp_read_main_file(), then the default target is used.  */
 433 void
 434 cpp_add_dependency_target (cpp_reader *pfile, const char *target, int quote)
 435 {
 436   if (!pfile->deps)
 437     pfile->deps = deps_init ();
 438
 439   deps_add_target (pfile->deps, target, quote);
 440 }
 441
 442 /* This is called after options have been parsed, and partially
 443    processed.  */
 444 void
 445 cpp_post_options (cpp_reader *pfile)
 446 {
 447   sanity_checks (pfile);
 448
 449   post_options (pfile);
 450
 451   /* Mark named operators before handling command line macros.  */
 452   if (CPP_OPTION (pfile, cplusplus) && CPP_OPTION (pfile, operator_names))
 453     mark_named_operators (pfile);
 454 }
 455
 456 /* Setup for processing input from the file named FNAME, or stdin if
 457    it is the empty string.  Return the original filename
 458    on success (e.g. foo.i->foo.c), or NULL on failure.  */
 459 const char *
 460 cpp_read_main_file (cpp_reader *pfile, const char *fname)
 461 {
 462   if (CPP_OPTION (pfile, deps.style) != DEPS_NONE)
 463     {
 464       if (!pfile->deps)
 465         pfile->deps = deps_init ();
 466
 467       /* Set the default target (if there is none already).  */
 468       deps_add_default_target (pfile->deps, fname);
 469     }
 470
 471   pfile->main_file
 472     = _cpp_find_file (pfile, fname, &pfile->no_search_path, false);
 473   if (_cpp_find_failed (pfile->main_file))
 474     return false;
 475
 476   _cpp_stack_file (pfile, pfile->main_file, false);
 477
 478   /* For foo.i, read the original filename foo.c now, for the benefit
 479      of the front ends.  */
 480   if (CPP_OPTION (pfile, preprocessed))
 481     {
 482       read_original_filename (pfile);
 483       fname = pfile->line_table->maps[pfile->line_table->used-1].to_file;
 484     }
 485   return fname;
 486 }
 487
 488 /* For preprocessed files, if the first tokens are of the form # NUM.
 489    handle the directive so we know the original file name.  This will
 490    generate file_change callbacks, which the front ends must handle
 491    appropriately given their state of initialization.  */
 492 static void
 493 read_original_filename (cpp_reader *pfile)
 494 {
 495   const cpp_token *token, *token1;
 496
 497   /* Lex ahead; if the first tokens are of the form # NUM, then
 498      process the directive, otherwise back up.  */
 499   token = _cpp_lex_direct (pfile);
 500   if (token->type == CPP_HASH)
 501     {
 502       token1 = _cpp_lex_direct (pfile);
 503       _cpp_backup_tokens (pfile, 1);
 504
 505       /* If it's a #line directive, handle it.  */
 506       if (token1->type == CPP_NUMBER)
 507         {
 508           _cpp_handle_directive (pfile, token->flags & PREV_WHITE);
 509           read_original_directory (pfile);
 510           return;
 511         }
 512     }
 513
 514   /* Backup as if nothing happened.  */
 515   _cpp_backup_tokens (pfile, 1);
 516 }
 517
 518 /* For preprocessed files, if the tokens following the first filename
 519    line is of the form # <line> "/path/name//", handle the
 520    directive so we know the original current directory.  */
 521 static void
 522 read_original_directory (cpp_reader *pfile)
 523 {
 524   const cpp_token *hash, *token;
 525
 526   /* Lex ahead; if the first tokens are of the form # NUM, then
 527      process the directive, otherwise back up.  */
 528   hash = _cpp_lex_direct (pfile);
 529   if (hash->type != CPP_HASH)
 530     {
 531       _cpp_backup_tokens (pfile, 1);
 532       return;
 533     }
 534
 535   token = _cpp_lex_direct (pfile);
 536
 537   if (token->type != CPP_NUMBER)
 538     {
 539       _cpp_backup_tokens (pfile, 2);
 540       return;
 541     }
 542
 543   token = _cpp_lex_direct (pfile);
 544
 545   if (token->type != CPP_STRING
 546       || ! (token->val.str.len >= 5
 547             && token->val.str.text[token->val.str.len-2] == '/'
 548             && token->val.str.text[token->val.str.len-3] == '/'))
 549     {
 550       _cpp_backup_tokens (pfile, 3);
 551       return;
 552     }
 553
 554   if (pfile->cb.dir_change)
 555     {
 556       char *debugdir = alloca (token->val.str.len - 3);
 557
 558       memcpy (debugdir, (const char *) token->val.str.text + 1,
 559               token->val.str.len - 4);
 560       debugdir[token->val.str.len - 4] = '\0';
 561
 562       pfile->cb.dir_change (pfile, debugdir);
 563     }
 564 }
 565
 566 /* This is called at the end of preprocessing.  It pops the last
 567    buffer and writes dependency output, and returns the number of
 568    errors.
 569
 570    Maybe it should also reset state, such that you could call
 571    cpp_start_read with a new filename to restart processing.  */
 572 int
 573 cpp_finish (cpp_reader *pfile, FILE *deps_stream)
 574 {
 575   /* Warn about unused macros before popping the final buffer.  */
 576   if (CPP_OPTION (pfile, warn_unused_macros))
 577     cpp_forall_identifiers (pfile, _cpp_warn_if_unused_macro, NULL);
 578
 579   /* cpplex.c leaves the final buffer on the stack.  This it so that
 580      it returns an unending stream of CPP_EOFs to the client.  If we
 581      popped the buffer, we'd dereference a NULL buffer pointer and
 582      segfault.  It's nice to allow the client to do worry-free excess
 583      cpp_get_token calls.  */
 584   while (pfile->buffer)
 585     _cpp_pop_buffer (pfile);
 586
 587   /* Don't write the deps file if there are errors.  */
 588   if (CPP_OPTION (pfile, deps.style) != DEPS_NONE
 589       && deps_stream && pfile->errors == 0)
 590     {
 591       deps_write (pfile->deps, deps_stream, 72);
 592
 593       if (CPP_OPTION (pfile, deps.phony_targets))
 594         deps_phony_targets (pfile->deps, deps_stream);
 595     }
 596
 597   /* Report on headers that could use multiple include guards.  */
 598   if (CPP_OPTION (pfile, print_include_names))
 599     _cpp_report_missing_guards (pfile);
 600
 601   return pfile->errors;
 602 }
 603
 604 static void
 605 post_options (cpp_reader *pfile)
 606 {
 607   /* -Wtraditional is not useful in C++ mode.  */
 608   if (CPP_OPTION (pfile, cplusplus))
 609     CPP_OPTION (pfile, warn_traditional) = 0;
 610
 611   /* Permanently disable macro expansion if we are rescanning
 612      preprocessed text.  Read preprocesed source in ISO mode.  */
 613   if (CPP_OPTION (pfile, preprocessed))
 614     {
 615       pfile->state.prevent_expansion = 1;
 616       CPP_OPTION (pfile, traditional) = 0;
 617     }
 618
 619   if (CPP_OPTION (pfile, warn_trigraphs) == 2)
 620     CPP_OPTION (pfile, warn_trigraphs) = !CPP_OPTION (pfile, trigraphs);
 621
 622   if (CPP_OPTION (pfile, traditional))
 623     {
 624       /* Traditional CPP does not accurately track column information.  */
 625       CPP_OPTION (pfile, show_column) = 0;
 626       CPP_OPTION (pfile, trigraphs) = 0;
 627       CPP_OPTION (pfile, warn_trigraphs) = 0;
 628     }
 629 }