libcpp/init.c

   1 /* CPP Library.
   2    Copyright (C) 1986, 1987, 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
   3    1999, 2000, 2001, 2002, 2003, 2004, 2005 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, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */
  21
  22 #include "config.h"
  23 #include "system.h"
  24 #include "cpplib.h"
  25 #include "internal.h"
  26 #include "mkdeps.h"
  27 #include "localedir.h"
  28
  29 static void init_library (void);
  30 static void mark_named_operators (cpp_reader *);
  31 static void read_original_filename (cpp_reader *);
  32 static void read_original_directory (cpp_reader *);
  33 static void post_options (cpp_reader *);
  34
  35 /* If we have designated initializers (GCC >2.7) these tables can be
  36    initialized, constant data.  Otherwise, they have to be filled in at
  37    runtime.  */
  38 #if HAVE_DESIGNATED_INITIALIZERS
  39
  40 #define init_trigraph_map()  /* Nothing.  */
  41 #define TRIGRAPH_MAP \
  42 __extension__ const uchar _cpp_trigraph_map[UCHAR_MAX + 1] = {
  43
  44 #define END };
  45 #define s(p, v) [p] = v,
  46
  47 #else
  48
  49 #define TRIGRAPH_MAP uchar _cpp_trigraph_map[UCHAR_MAX + 1] = { 0 }; \
  50  static void init_trigraph_map (void) { \
  51  unsigned char *x = _cpp_trigraph_map;
  52
  53 #define END }
  54 #define s(p, v) x[p] = v;
  55
  56 #endif
  57
  58 TRIGRAPH_MAP
  59   s('=', '#')   s(')', ']')     s('!', '|')
  60   s('(', '[')   s('\'', '^')    s('>', '}')
  61   s('/', '\\')  s('<', '{')     s('-', '~')
  62 END
  63
  64 #undef s
  65 #undef END
  66 #undef TRIGRAPH_MAP
  67
  68 /* A set of booleans indicating what CPP features each source language
  69    requires.  */
  70 struct lang_flags
  71 {
  72   char c99;
  73   char cplusplus;
  74   char extended_numbers;
  75   char extended_identifiers;
  76   char std;
  77   char cplusplus_comments;
  78   char digraphs;
  79 };
  80
  81 static const struct lang_flags lang_defaults[] =
  82 { /*              c99 c++ xnum xid std  //   digr  */
  83   /* GNUC89 */  { 0,  0,  1,   0,  0,   1,   1     },
  84   /* GNUC99 */  { 1,  0,  1,   0,  0,   1,   1     },
  85   /* STDC89 */  { 0,  0,  0,   0,  1,   0,   0     },
  86   /* STDC94 */  { 0,  0,  0,   0,  1,   0,   1     },
  87   /* STDC99 */  { 1,  0,  1,   0,  1,   1,   1     },
  88   /* GNUCXX */  { 0,  1,  1,   0,  0,   1,   1     },
  89   /* CXX98  */  { 0,  1,  1,   0,  1,   1,   1     },
  90   /* ASM    */  { 0,  0,  1,   0,  0,   1,   0     }
  91   /* xid should be 1 for GNUC99, STDC99, GNUCXX and CXX98 when no
  92      longer experimental (when all uses of identifiers in the compiler
  93      have been audited for correct handling of extended
  94      identifiers).  */
  95 };
  96
  97 /* Sets internal flags correctly for a given language.  */
  98 void
  99 cpp_set_lang (cpp_reader *pfile, enum c_lang lang)
 100 {
 101   const struct lang_flags *l = &lang_defaults[(int) lang];
 102
 103   CPP_OPTION (pfile, lang) = lang;
 104
 105   CPP_OPTION (pfile, c99)                        = l->c99;
 106   CPP_OPTION (pfile, cplusplus)                  = l->cplusplus;
 107   CPP_OPTION (pfile, extended_numbers)           = l->extended_numbers;
 108   CPP_OPTION (pfile, extended_identifiers)       = l->extended_identifiers;
 109   CPP_OPTION (pfile, std)                        = l->std;
 110   CPP_OPTION (pfile, trigraphs)                  = l->std;
 111   CPP_OPTION (pfile, cplusplus_comments)         = l->cplusplus_comments;
 112   CPP_OPTION (pfile, digraphs)                   = l->digraphs;
 113 }
 114
 115 /* Initialize library global state.  */
 116 static void
 117 init_library (void)
 118 {
 119   static int initialized = 0;
 120
 121   if (! initialized)
 122     {
 123       initialized = 1;
 124
 125       /* Set up the trigraph map.  This doesn't need to do anything if
 126          we were compiled with a compiler that supports C99 designated
 127          initializers.  */
 128       init_trigraph_map ();
 129
 130 #ifdef ENABLE_NLS
 131        (void) bindtextdomain (PACKAGE, LOCALEDIR);
 132 #endif
 133     }
 134 }
 135
 136 /* Initialize a cpp_reader structure.  */
 137 cpp_reader *
 138 cpp_create_reader (enum c_lang lang, hash_table *table,
 139                    struct line_maps *line_table)
 140 {
 141   cpp_reader *pfile;
 142
 143   /* Initialize this instance of the library if it hasn't been already.  */
 144   init_library ();
 145
 146   pfile = XCNEW (cpp_reader);
 147
 148   cpp_set_lang (pfile, lang);
 149   CPP_OPTION (pfile, warn_multichar) = 1;
 150   CPP_OPTION (pfile, discard_comments) = 1;
 151   CPP_OPTION (pfile, discard_comments_in_macro_exp) = 1;
 152   CPP_OPTION (pfile, show_column) = 1;
 153   CPP_OPTION (pfile, tabstop) = 8;
 154   CPP_OPTION (pfile, operator_names) = 1;
 155   CPP_OPTION (pfile, warn_trigraphs) = 2;
 156   CPP_OPTION (pfile, warn_endif_labels) = 1;
 157   CPP_OPTION (pfile, warn_deprecated) = 1;
 158   CPP_OPTION (pfile, warn_long_long) = !CPP_OPTION (pfile, c99);
 159   CPP_OPTION (pfile, dollars_in_ident) = 1;
 160   CPP_OPTION (pfile, warn_dollars) = 1;
 161   CPP_OPTION (pfile, warn_variadic_macros) = 1;
 162   CPP_OPTION (pfile, warn_normalize) = normalized_C;
 163
 164   /* Default CPP arithmetic to something sensible for the host for the
 165      benefit of dumb users like fix-header.  */
 166   CPP_OPTION (pfile, precision) = CHAR_BIT * sizeof (long);
 167   CPP_OPTION (pfile, char_precision) = CHAR_BIT;
 168   CPP_OPTION (pfile, wchar_precision) = CHAR_BIT * sizeof (int);
 169   CPP_OPTION (pfile, int_precision) = CHAR_BIT * sizeof (int);
 170   CPP_OPTION (pfile, unsigned_char) = 0;
 171   CPP_OPTION (pfile, unsigned_wchar) = 1;
 172   CPP_OPTION (pfile, bytes_big_endian) = 1;  /* does not matter */
 173
 174   /* Default to no charset conversion.  */
 175   CPP_OPTION (pfile, narrow_charset) = _cpp_default_encoding ();
 176   CPP_OPTION (pfile, wide_charset) = 0;
 177
 178   /* Default the input character set to UTF-8.  */
 179   CPP_OPTION (pfile, input_charset) = _cpp_default_encoding ();
 180
 181   /* A fake empty "directory" used as the starting point for files
 182      looked up without a search path.  Name cannot be '/' because we
 183      don't want to prepend anything at all to filenames using it.  All
 184      other entries are correct zero-initialized.  */
 185   pfile->no_search_path.name = (char *) "";
 186
 187   /* Initialize the line map.  */
 188   pfile->line_table = line_table;
 189
 190   /* Initialize lexer state.  */
 191   pfile->state.save_comments = ! CPP_OPTION (pfile, discard_comments);
 192
 193   /* Set up static tokens.  */
 194   pfile->avoid_paste.type = CPP_PADDING;
 195   pfile->avoid_paste.val.source = NULL;
 196   pfile->eof.type = CPP_EOF;
 197   pfile->eof.flags = 0;
 198
 199   /* Create a token buffer for the lexer.  */
 200   _cpp_init_tokenrun (&pfile->base_run, 250);
 201   pfile->cur_run = &pfile->base_run;
 202   pfile->cur_token = pfile->base_run.base;
 203
 204   /* Initialize the base context.  */
 205   pfile->context = &pfile->base_context;
 206   pfile->base_context.macro = 0;
 207   pfile->base_context.prev = pfile->base_context.next = 0;
 208
 209   /* Aligned and unaligned storage.  */
 210   pfile->a_buff = _cpp_get_buff (pfile, 0);
 211   pfile->u_buff = _cpp_get_buff (pfile, 0);
 212
 213   /* The expression parser stack.  */
 214   _cpp_expand_op_stack (pfile);
 215
 216   /* Initialize the buffer obstack.  */
 217   _obstack_begin (&pfile->buffer_ob, 0, 0,
 218                   (void *(*) (long)) xmalloc,
 219                   (void (*) (void *)) free);
 220
 221   _cpp_init_files (pfile);
 222
 223   _cpp_init_hashtable (pfile, table);
 224
 225   return pfile;
 226 }
 227
 228 /* Free resources used by PFILE.  Accessing PFILE after this function
 229    returns leads to undefined behavior.  Returns the error count.  */
 230 void
 231 cpp_destroy (cpp_reader *pfile)
 232 {
 233   cpp_context *context, *contextn;
 234   tokenrun *run, *runn;
 235
 236   free (pfile->op_stack);
 237
 238   while (CPP_BUFFER (pfile) != NULL)
 239     _cpp_pop_buffer (pfile);
 240
 241   if (pfile->out.base)
 242     free (pfile->out.base);
 243
 244   if (pfile->macro_buffer)
 245     {
 246       free (pfile->macro_buffer);
 247       pfile->macro_buffer = NULL;
 248       pfile->macro_buffer_len = 0;
 249     }
 250
 251   if (pfile->deps)
 252     deps_free (pfile->deps);
 253   obstack_free (&pfile->buffer_ob, 0);
 254
 255   _cpp_destroy_hashtable (pfile);
 256   _cpp_cleanup_files (pfile);
 257   _cpp_destroy_iconv (pfile);
 258
 259   _cpp_free_buff (pfile->a_buff);
 260   _cpp_free_buff (pfile->u_buff);
 261   _cpp_free_buff (pfile->free_buffs);
 262
 263   for (run = &pfile->base_run; run; run = runn)
 264     {
 265       runn = run->next;
 266       free (run->base);
 267       if (run != &pfile->base_run)
 268         free (run);
 269     }
 270
 271   for (context = pfile->base_context.next; context; context = contextn)
 272     {
 273       contextn = context->next;
 274       free (context);
 275     }
 276
 277   free (pfile);
 278 }
 279
 280 /* This structure defines one built-in identifier.  A node will be
 281    entered in the hash table under the name NAME, with value VALUE.
 282
 283    There are two tables of these.  builtin_array holds all the
 284    "builtin" macros: these are handled by builtin_macro() in
 285    macro.c.  Builtin is somewhat of a misnomer -- the property of
 286    interest is that these macros require special code to compute their
 287    expansions.  The value is a "builtin_type" enumerator.
 288
 289    operator_array holds the C++ named operators.  These are keywords
 290    which act as aliases for punctuators.  In C++, they cannot be
 291    altered through #define, and #if recognizes them as operators.  In
 292    C, these are not entered into the hash table at all (but see
 293    <iso646.h>).  The value is a token-type enumerator.  */
 294 struct builtin
 295 {
 296   const uchar *name;
 297   unsigned short len;
 298   unsigned short value;
 299 };
 300
 301 #define B(n, t)    { DSC(n), t }
 302 static const struct builtin builtin_array[] =
 303 {
 304   B("__TIME__",          BT_TIME),
 305   B("__DATE__",          BT_DATE),
 306   B("__FILE__",          BT_FILE),
 307   B("__BASE_FILE__",     BT_BASE_FILE),
 308   B("__LINE__",          BT_SPECLINE),
 309   B("__INCLUDE_LEVEL__", BT_INCLUDE_LEVEL),
 310   /* Keep builtins not used for -traditional-cpp at the end, and
 311      update init_builtins() if any more are added.  */
 312   B("_Pragma",           BT_PRAGMA),
 313   B("__STDC__",          BT_STDC),
 314 };
 315
 316 static const struct builtin operator_array[] =
 317 {
 318   B("and",      CPP_AND_AND),
 319   B("and_eq",   CPP_AND_EQ),
 320   B("bitand",   CPP_AND),
 321   B("bitor",    CPP_OR),
 322   B("compl",    CPP_COMPL),
 323   B("not",      CPP_NOT),
 324   B("not_eq",   CPP_NOT_EQ),
 325   B("or",       CPP_OR_OR),
 326   B("or_eq",    CPP_OR_EQ),
 327   B("xor",      CPP_XOR),
 328   B("xor_eq",   CPP_XOR_EQ)
 329 };
 330 #undef B
 331
 332 /* Mark the C++ named operators in the hash table.  */
 333 static void
 334 mark_named_operators (cpp_reader *pfile)
 335 {
 336   const struct builtin *b;
 337
 338   for (b = operator_array;
 339        b < (operator_array + ARRAY_SIZE (operator_array));
 340        b++)
 341     {
 342       cpp_hashnode *hp = cpp_lookup (pfile, b->name, b->len);
 343       hp->flags |= NODE_OPERATOR;
 344       hp->is_directive = 0;
 345       hp->directive_index = b->value;
 346     }
 347 }
 348
 349 /* Read the builtins table above and enter them, and language-specific
 350    macros, into the hash table.  HOSTED is true if this is a hosted
 351    environment.  */
 352 void
 353 cpp_init_builtins (cpp_reader *pfile, int hosted)
 354 {
 355   const struct builtin *b;
 356   size_t n = ARRAY_SIZE (builtin_array);
 357
 358   if (CPP_OPTION (pfile, traditional))
 359     n -= 2;
 360
 361   for(b = builtin_array; b < builtin_array + n; b++)
 362     {
 363       cpp_hashnode *hp = cpp_lookup (pfile, b->name, b->len);
 364       hp->type = NT_MACRO;
 365       hp->flags |= NODE_BUILTIN | NODE_WARN;
 366       hp->value.builtin = (enum builtin_type) b->value;
 367     }
 368
 369   if (CPP_OPTION (pfile, cplusplus))
 370     _cpp_define_builtin (pfile, "__cplusplus 1");
 371   else if (CPP_OPTION (pfile, lang) == CLK_ASM)
 372     _cpp_define_builtin (pfile, "__ASSEMBLER__ 1");
 373   else if (CPP_OPTION (pfile, lang) == CLK_STDC94)
 374     _cpp_define_builtin (pfile, "__STDC_VERSION__ 199409L");
 375   else if (CPP_OPTION (pfile, c99))
 376     _cpp_define_builtin (pfile, "__STDC_VERSION__ 199901L");
 377
 378   if (hosted)
 379     _cpp_define_builtin (pfile, "__STDC_HOSTED__ 1");
 380   else
 381     _cpp_define_builtin (pfile, "__STDC_HOSTED__ 0");
 382
 383   if (CPP_OPTION (pfile, objc))
 384     _cpp_define_builtin (pfile, "__OBJC__ 1");
 385 }
 386
 387 /* Sanity-checks are dependent on command-line options, so it is
 388    called as a subroutine of cpp_read_main_file ().  */
 389 #if ENABLE_CHECKING
 390 static void sanity_checks (cpp_reader *);
 391 static void sanity_checks (cpp_reader *pfile)
 392 {
 393   cppchar_t test = 0;
 394   size_t max_precision = 2 * CHAR_BIT * sizeof (cpp_num_part);
 395
 396   /* Sanity checks for assumptions about CPP arithmetic and target
 397      type precisions made by cpplib.  */
 398   test--;
 399   if (test < 1)
 400     cpp_error (pfile, CPP_DL_ICE, "cppchar_t must be an unsigned type");
 401
 402   if (CPP_OPTION (pfile, precision) > max_precision)
 403     cpp_error (pfile, CPP_DL_ICE,
 404                "preprocessor arithmetic has maximum precision of %lu bits;"
 405                " target requires %lu bits",
 406                (unsigned long) max_precision,
 407                (unsigned long) CPP_OPTION (pfile, precision));
 408
 409   if (CPP_OPTION (pfile, precision) < CPP_OPTION (pfile, int_precision))
 410     cpp_error (pfile, CPP_DL_ICE,
 411                "CPP arithmetic must be at least as precise as a target int");
 412
 413   if (CPP_OPTION (pfile, char_precision) < 8)
 414     cpp_error (pfile, CPP_DL_ICE, "target char is less than 8 bits wide");
 415
 416   if (CPP_OPTION (pfile, wchar_precision) < CPP_OPTION (pfile, char_precision))
 417     cpp_error (pfile, CPP_DL_ICE,
 418                "target wchar_t is narrower than target char");
 419
 420   if (CPP_OPTION (pfile, int_precision) < CPP_OPTION (pfile, char_precision))
 421     cpp_error (pfile, CPP_DL_ICE,
 422                "target int is narrower than target char");
 423
 424   /* This is assumed in eval_token() and could be fixed if necessary.  */
 425   if (sizeof (cppchar_t) > sizeof (cpp_num_part))
 426     cpp_error (pfile, CPP_DL_ICE,
 427                "CPP half-integer narrower than CPP character");
 428
 429   if (CPP_OPTION (pfile, wchar_precision) > BITS_PER_CPPCHAR_T)
 430     cpp_error (pfile, CPP_DL_ICE,
 431                "CPP on this host cannot handle wide character constants over"
 432                " %lu bits, but the target requires %lu bits",
 433                (unsigned long) BITS_PER_CPPCHAR_T,
 434                (unsigned long) CPP_OPTION (pfile, wchar_precision));
 435 }
 436 #else
 437 # define sanity_checks(PFILE)
 438 #endif
 439
 440 /* This is called after options have been parsed, and partially
 441    processed.  */
 442 void
 443 cpp_post_options (cpp_reader *pfile)
 444 {
 445   sanity_checks (pfile);
 446
 447   post_options (pfile);
 448
 449   /* Mark named operators before handling command line macros.  */
 450   if (CPP_OPTION (pfile, cplusplus) && CPP_OPTION (pfile, operator_names))
 451     mark_named_operators (pfile);
 452 }
 453
 454 /* Setup for processing input from the file named FNAME, or stdin if
 455    it is the empty string.  Return the original filename
 456    on success (e.g. foo.i->foo.c), or NULL on failure.  */
 457 const char *
 458 cpp_read_main_file (cpp_reader *pfile, const char *fname)
 459 {
 460   if (CPP_OPTION (pfile, deps.style) != DEPS_NONE)
 461     {
 462       if (!pfile->deps)
 463         pfile->deps = deps_init ();
 464
 465       /* Set the default target (if there is none already).  */
 466       deps_add_default_target (pfile->deps, fname);
 467     }
 468
 469   pfile->main_file
 470     = _cpp_find_file (pfile, fname, &pfile->no_search_path, false, 0);
 471   if (_cpp_find_failed (pfile->main_file))
 472     return NULL;
 473
 474   _cpp_stack_file (pfile, pfile->main_file, false);
 475
 476   /* For foo.i, read the original filename foo.c now, for the benefit
 477      of the front ends.  */
 478   if (CPP_OPTION (pfile, preprocessed))
 479     {
 480       read_original_filename (pfile);
 481       fname = pfile->line_table->maps[pfile->line_table->used-1].to_file;
 482     }
 483   return fname;
 484 }
 485
 486 /* For preprocessed files, if the first tokens are of the form # NUM.
 487    handle the directive so we know the original file name.  This will
 488    generate file_change callbacks, which the front ends must handle
 489    appropriately given their state of initialization.  */
 490 static void
 491 read_original_filename (cpp_reader *pfile)
 492 {
 493   const cpp_token *token, *token1;
 494
 495   /* Lex ahead; if the first tokens are of the form # NUM, then
 496      process the directive, otherwise back up.  */
 497   token = _cpp_lex_direct (pfile);
 498   if (token->type == CPP_HASH)
 499     {
 500       token1 = _cpp_lex_direct (pfile);
 501       _cpp_backup_tokens (pfile, 1);
 502
 503       /* If it's a #line directive, handle it.  */
 504       if (token1->type == CPP_NUMBER)
 505         {
 506           _cpp_handle_directive (pfile, token->flags & PREV_WHITE);
 507           read_original_directory (pfile);
 508           return;
 509         }
 510     }
 511
 512   /* Backup as if nothing happened.  */
 513   _cpp_backup_tokens (pfile, 1);
 514 }
 515
 516 /* For preprocessed files, if the tokens following the first filename
 517    line is of the form # <line> "/path/name//", handle the
 518    directive so we know the original current directory.  */
 519 static void
 520 read_original_directory (cpp_reader *pfile)
 521 {
 522   const cpp_token *hash, *token;
 523
 524   /* Lex ahead; if the first tokens are of the form # NUM, then
 525      process the directive, otherwise back up.  */
 526   hash = _cpp_lex_direct (pfile);
 527   if (hash->type != CPP_HASH)
 528     {
 529       _cpp_backup_tokens (pfile, 1);
 530       return;
 531     }
 532
 533   token = _cpp_lex_direct (pfile);
 534
 535   if (token->type != CPP_NUMBER)
 536     {
 537       _cpp_backup_tokens (pfile, 2);
 538       return;
 539     }
 540
 541   token = _cpp_lex_direct (pfile);
 542
 543   if (token->type != CPP_STRING
 544       || ! (token->val.str.len >= 5
 545             && token->val.str.text[token->val.str.len-2] == '/'
 546             && token->val.str.text[token->val.str.len-3] == '/'))
 547     {
 548       _cpp_backup_tokens (pfile, 3);
 549       return;
 550     }
 551
 552   if (pfile->cb.dir_change)
 553     {
 554       char *debugdir = (char *) alloca (token->val.str.len - 3);
 555
 556       memcpy (debugdir, (const char *) token->val.str.text + 1,
 557               token->val.str.len - 4);
 558       debugdir[token->val.str.len - 4] = '\0';
 559
 560       pfile->cb.dir_change (pfile, debugdir);
 561     }
 562 }
 563
 564 /* This is called at the end of preprocessing.  It pops the last
 565    buffer and writes dependency output, and returns the number of
 566    errors.
 567
 568    Maybe it should also reset state, such that you could call
 569    cpp_start_read with a new filename to restart processing.  */
 570 int
 571 cpp_finish (cpp_reader *pfile, FILE *deps_stream)
 572 {
 573   /* Warn about unused macros before popping the final buffer.  */
 574   if (CPP_OPTION (pfile, warn_unused_macros))
 575     cpp_forall_identifiers (pfile, _cpp_warn_if_unused_macro, NULL);
 576
 577   /* lex.c leaves the final buffer on the stack.  This it so that
 578      it returns an unending stream of CPP_EOFs to the client.  If we
 579      popped the buffer, we'd dereference a NULL buffer pointer and
 580      segfault.  It's nice to allow the client to do worry-free excess
 581      cpp_get_token calls.  */
 582   while (pfile->buffer)
 583     _cpp_pop_buffer (pfile);
 584
 585   /* Don't write the deps file if there are errors.  */
 586   if (CPP_OPTION (pfile, deps.style) != DEPS_NONE
 587       && deps_stream && pfile->errors == 0)
 588     {
 589       deps_write (pfile->deps, deps_stream, 72);
 590
 591       if (CPP_OPTION (pfile, deps.phony_targets))
 592         deps_phony_targets (pfile->deps, deps_stream);
 593     }
 594
 595   /* Report on headers that could use multiple include guards.  */
 596   if (CPP_OPTION (pfile, print_include_names))
 597     _cpp_report_missing_guards (pfile);
 598
 599   return pfile->errors;
 600 }
 601
 602 static void
 603 post_options (cpp_reader *pfile)
 604 {
 605   /* -Wtraditional is not useful in C++ mode.  */
 606   if (CPP_OPTION (pfile, cplusplus))
 607     CPP_OPTION (pfile, warn_traditional) = 0;
 608
 609   /* Permanently disable macro expansion if we are rescanning
 610      preprocessed text.  Read preprocesed source in ISO mode.  */
 611   if (CPP_OPTION (pfile, preprocessed))
 612     {
 613       pfile->state.prevent_expansion = 1;
 614       CPP_OPTION (pfile, traditional) = 0;
 615     }
 616
 617   if (CPP_OPTION (pfile, warn_trigraphs) == 2)
 618     CPP_OPTION (pfile, warn_trigraphs) = !CPP_OPTION (pfile, trigraphs);
 619
 620   if (CPP_OPTION (pfile, traditional))
 621     {
 622       CPP_OPTION (pfile, cplusplus_comments) = 0;
 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 }