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, 2007, 2008,
   4    2009 Free Software Foundation, Inc.
   5    Contributed by Per Bothner, 1994-95.
   6    Based on CCCP program by Paul Rubin, June 1986
   7    Adapted to ANSI C, Richard Stallman, Jan 1987
   8
   9 This program is free software; you can redistribute it and/or modify it
  10 under the terms of the GNU General Public License as published by the
  11 Free Software Foundation; either version 2, or (at your option) any
  12 later version.
  13
  14 This program is distributed in the hope that it will be useful,
  15 but WITHOUT ANY WARRANTY; without even the implied warranty of
  16 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17 GNU General Public License for more details.
  18
  19 You should have received a copy of the GNU General Public License
  20 along with this program; if not, write to the Free Software
  21 Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */
  22
  23 #include "config.h"
  24 #include "system.h"
  25 #include "cpplib.h"
  26 #include "internal.h"
  27 #include "mkdeps.h"
  28 #include "localedir.h"
  29
  30 static void init_library (void);
  31 static void mark_named_operators (cpp_reader *);
  32 static void read_original_filename (cpp_reader *);
  33 static void read_original_directory (cpp_reader *);
  34 static void post_options (cpp_reader *);
  35
  36 /* If we have designated initializers (GCC >2.7) these tables can be
  37    initialized, constant data.  Otherwise, they have to be filled in at
  38    runtime.  */
  39 #if HAVE_DESIGNATED_INITIALIZERS
  40
  41 #define init_trigraph_map()  /* Nothing.  */
  42 #define TRIGRAPH_MAP \
  43 __extension__ const uchar _cpp_trigraph_map[UCHAR_MAX + 1] = {
  44
  45 #define END };
  46 #define s(p, v) [p] = v,
  47
  48 #else
  49
  50 #define TRIGRAPH_MAP uchar _cpp_trigraph_map[UCHAR_MAX + 1] = { 0 }; \
  51  static void init_trigraph_map (void) { \
  52  unsigned char *x = _cpp_trigraph_map;
  53
  54 #define END }
  55 #define s(p, v) x[p] = v;
  56
  57 #endif
  58
  59 TRIGRAPH_MAP
  60   s('=', '#')   s(')', ']')     s('!', '|')
  61   s('(', '[')   s('\'', '^')    s('>', '}')
  62   s('/', '\\')  s('<', '{')     s('-', '~')
  63 END
  64
  65 #undef s
  66 #undef END
  67 #undef TRIGRAPH_MAP
  68
  69 /* A set of booleans indicating what CPP features each source language
  70    requires.  */
  71 struct lang_flags
  72 {
  73   char c99;
  74   char cplusplus;
  75   char extended_numbers;
  76   char extended_identifiers;
  77   char std;
  78   char cplusplus_comments;
  79   char digraphs;
  80   char uliterals;
  81 };
  82
  83 static const struct lang_flags lang_defaults[] =
  84 { /*              c99 c++ xnum xid std  //   digr ulit */
  85   /* GNUC89   */  { 0,  0,  1,   0,  0,   1,   1,   0 },
  86   /* GNUC99   */  { 1,  0,  1,   0,  0,   1,   1,   1 },
  87   /* STDC89   */  { 0,  0,  0,   0,  1,   0,   0,   0 },
  88   /* STDC94   */  { 0,  0,  0,   0,  1,   0,   1,   0 },
  89   /* STDC99   */  { 1,  0,  1,   0,  1,   1,   1,   0 },
  90   /* GNUCXX   */  { 0,  1,  1,   0,  0,   1,   1,   0 },
  91   /* CXX98    */  { 0,  1,  1,   0,  1,   1,   1,   0 },
  92   /* GNUCXX0X */  { 1,  1,  1,   0,  0,   1,   1,   1 },
  93   /* CXX0X    */  { 1,  1,  1,   0,  1,   1,   1,   1 },
  94   /* ASM      */  { 0,  0,  1,   0,  0,   1,   0,   0 }
  95   /* xid should be 1 for GNUC99, STDC99, GNUCXX, CXX98, GNUCXX0X, and
  96      CXX0X when no longer experimental (when all uses of identifiers
  97      in the compiler have been audited for correct handling of
  98      extended identifiers).  */
  99 };
 100
 101 /* Sets internal flags correctly for a given language.  */
 102 void
 103 cpp_set_lang (cpp_reader *pfile, enum c_lang lang)
 104 {
 105   const struct lang_flags *l = &lang_defaults[(int) lang];
 106
 107   CPP_OPTION (pfile, lang) = lang;
 108
 109   CPP_OPTION (pfile, c99)                        = l->c99;
 110   CPP_OPTION (pfile, cplusplus)                  = l->cplusplus;
 111   CPP_OPTION (pfile, extended_numbers)           = l->extended_numbers;
 112   CPP_OPTION (pfile, extended_identifiers)       = l->extended_identifiers;
 113   CPP_OPTION (pfile, std)                        = l->std;
 114   CPP_OPTION (pfile, trigraphs)                  = l->std;
 115   CPP_OPTION (pfile, cplusplus_comments)         = l->cplusplus_comments;
 116   CPP_OPTION (pfile, digraphs)                   = l->digraphs;
 117   CPP_OPTION (pfile, uliterals)                  = l->uliterals;
 118 }
 119
 120 /* Initialize library global state.  */
 121 static void
 122 init_library (void)
 123 {
 124   static int initialized = 0;
 125
 126   if (! initialized)
 127     {
 128       initialized = 1;
 129
 130       /* Set up the trigraph map.  This doesn't need to do anything if
 131          we were compiled with a compiler that supports C99 designated
 132          initializers.  */
 133       init_trigraph_map ();
 134
 135 #ifdef ENABLE_NLS
 136        (void) bindtextdomain (PACKAGE, LOCALEDIR);
 137 #endif
 138     }
 139 }
 140
 141 /* Initialize a cpp_reader structure.  */
 142 cpp_reader *
 143 cpp_create_reader (enum c_lang lang, hash_table *table,
 144                    struct line_maps *line_table)
 145 {
 146   cpp_reader *pfile;
 147
 148   /* Initialize this instance of the library if it hasn't been already.  */
 149   init_library ();
 150
 151   pfile = XCNEW (cpp_reader);
 152
 153   cpp_set_lang (pfile, lang);
 154   CPP_OPTION (pfile, warn_multichar) = 1;
 155   CPP_OPTION (pfile, discard_comments) = 1;
 156   CPP_OPTION (pfile, discard_comments_in_macro_exp) = 1;
 157   CPP_OPTION (pfile, show_column) = 1;
 158   CPP_OPTION (pfile, tabstop) = 8;
 159   CPP_OPTION (pfile, operator_names) = 1;
 160   CPP_OPTION (pfile, warn_trigraphs) = 2;
 161   CPP_OPTION (pfile, warn_endif_labels) = 1;
 162   CPP_OPTION (pfile, warn_deprecated) = 1;
 163   CPP_OPTION (pfile, warn_long_long) = !CPP_OPTION (pfile, c99);
 164   CPP_OPTION (pfile, dollars_in_ident) = 1;
 165   CPP_OPTION (pfile, warn_dollars) = 1;
 166   CPP_OPTION (pfile, warn_variadic_macros) = 1;
 167   CPP_OPTION (pfile, warn_builtin_macro_redefined) = 1;
 168   CPP_OPTION (pfile, warn_normalize) = normalized_C;
 169
 170   /* Default CPP arithmetic to something sensible for the host for the
 171      benefit of dumb users like fix-header.  */
 172   CPP_OPTION (pfile, precision) = CHAR_BIT * sizeof (long);
 173   CPP_OPTION (pfile, char_precision) = CHAR_BIT;
 174   CPP_OPTION (pfile, wchar_precision) = CHAR_BIT * sizeof (int);
 175   CPP_OPTION (pfile, int_precision) = CHAR_BIT * sizeof (int);
 176   CPP_OPTION (pfile, unsigned_char) = 0;
 177   CPP_OPTION (pfile, unsigned_wchar) = 1;
 178   CPP_OPTION (pfile, bytes_big_endian) = 1;  /* does not matter */
 179
 180   /* Default to no charset conversion.  */
 181   CPP_OPTION (pfile, narrow_charset) = _cpp_default_encoding ();
 182   CPP_OPTION (pfile, wide_charset) = 0;
 183
 184   /* Default the input character set to UTF-8.  */
 185   CPP_OPTION (pfile, input_charset) = _cpp_default_encoding ();
 186
 187   /* A fake empty "directory" used as the starting point for files
 188      looked up without a search path.  Name cannot be '/' because we
 189      don't want to prepend anything at all to filenames using it.  All
 190      other entries are correct zero-initialized.  */
 191   pfile->no_search_path.name = (char *) "";
 192
 193   /* Initialize the line map.  */
 194   pfile->line_table = line_table;
 195
 196   /* Initialize lexer state.  */
 197   pfile->state.save_comments = ! CPP_OPTION (pfile, discard_comments);
 198
 199   /* Set up static tokens.  */
 200   pfile->avoid_paste.type = CPP_PADDING;
 201   pfile->avoid_paste.val.source = NULL;
 202   pfile->eof.type = CPP_EOF;
 203   pfile->eof.flags = 0;
 204
 205   /* Create a token buffer for the lexer.  */
 206   _cpp_init_tokenrun (&pfile->base_run, 250);
 207   pfile->cur_run = &pfile->base_run;
 208   pfile->cur_token = pfile->base_run.base;
 209
 210   /* Initialize the base context.  */
 211   pfile->context = &pfile->base_context;
 212   pfile->base_context.macro = 0;
 213   pfile->base_context.prev = pfile->base_context.next = 0;
 214
 215   /* Aligned and unaligned storage.  */
 216   pfile->a_buff = _cpp_get_buff (pfile, 0);
 217   pfile->u_buff = _cpp_get_buff (pfile, 0);
 218
 219   /* The expression parser stack.  */
 220   _cpp_expand_op_stack (pfile);
 221
 222   /* Initialize the buffer obstack.  */
 223   _obstack_begin (&pfile->buffer_ob, 0, 0,
 224                   (void *(*) (long)) xmalloc,
 225                   (void (*) (void *)) free);
 226
 227   _cpp_init_files (pfile);
 228
 229   _cpp_init_hashtable (pfile, table);
 230
 231   return pfile;
 232 }
 233
 234 /* Set the line_table entry in PFILE.  This is called after reading a
 235    PCH file, as the old line_table will be incorrect.  */
 236 void
 237 cpp_set_line_map (cpp_reader *pfile, struct line_maps *line_table)
 238 {
 239   pfile->line_table = line_table;
 240 }
 241
 242 /* Free resources used by PFILE.  Accessing PFILE after this function
 243    returns leads to undefined behavior.  Returns the error count.  */
 244 void
 245 cpp_destroy (cpp_reader *pfile)
 246 {
 247   cpp_context *context, *contextn;
 248   tokenrun *run, *runn;
 249   int i;
 250
 251   free (pfile->op_stack);
 252
 253   while (CPP_BUFFER (pfile) != NULL)
 254     _cpp_pop_buffer (pfile);
 255
 256   if (pfile->out.base)
 257     free (pfile->out.base);
 258
 259   if (pfile->macro_buffer)
 260     {
 261       free (pfile->macro_buffer);
 262       pfile->macro_buffer = NULL;
 263       pfile->macro_buffer_len = 0;
 264     }
 265
 266   if (pfile->deps)
 267     deps_free (pfile->deps);
 268   obstack_free (&pfile->buffer_ob, 0);
 269
 270   _cpp_destroy_hashtable (pfile);
 271   _cpp_cleanup_files (pfile);
 272   _cpp_destroy_iconv (pfile);
 273
 274   _cpp_free_buff (pfile->a_buff);
 275   _cpp_free_buff (pfile->u_buff);
 276   _cpp_free_buff (pfile->free_buffs);
 277
 278   for (run = &pfile->base_run; run; run = runn)
 279     {
 280       runn = run->next;
 281       free (run->base);
 282       if (run != &pfile->base_run)
 283         free (run);
 284     }
 285
 286   for (context = pfile->base_context.next; context; context = contextn)
 287     {
 288       contextn = context->next;
 289       free (context);
 290     }
 291
 292   if (pfile->comments.entries)
 293     {
 294       for (i = 0; i < pfile->comments.count; i++)
 295         free (pfile->comments.entries[i].comment);
 296
 297       free (pfile->comments.entries);
 298     }
 299
 300   free (pfile);
 301 }
 302
 303 /* This structure defines one built-in identifier.  A node will be
 304    entered in the hash table under the name NAME, with value VALUE.
 305
 306    There are two tables of these.  builtin_array holds all the
 307    "builtin" macros: these are handled by builtin_macro() in
 308    macro.c.  Builtin is somewhat of a misnomer -- the property of
 309    interest is that these macros require special code to compute their
 310    expansions.  The value is a "builtin_type" enumerator.
 311
 312    operator_array holds the C++ named operators.  These are keywords
 313    which act as aliases for punctuators.  In C++, they cannot be
 314    altered through #define, and #if recognizes them as operators.  In
 315    C, these are not entered into the hash table at all (but see
 316    <iso646.h>).  The value is a token-type enumerator.  */
 317 struct builtin_macro
 318 {
 319   const uchar *const name;
 320   const unsigned short len;
 321   const unsigned short value;
 322   const bool always_warn_if_redefined;
 323 };
 324
 325 #define B(n, t, f)    { DSC(n), t, f }
 326 static const struct builtin_macro builtin_array[] =
 327 {
 328   B("__TIMESTAMP__",     BT_TIMESTAMP,     false),
 329   B("__TIME__",          BT_TIME,          false),
 330   B("__DATE__",          BT_DATE,          false),
 331   B("__FILE__",          BT_FILE,          false),
 332   B("__BASE_FILE__",     BT_BASE_FILE,     false),
 333   B("__LINE__",          BT_SPECLINE,      true),
 334   B("__INCLUDE_LEVEL__", BT_INCLUDE_LEVEL, true),
 335   B("__COUNTER__",       BT_COUNTER,       true),
 336   /* Keep builtins not used for -traditional-cpp at the end, and
 337      update init_builtins() if any more are added.  */
 338   B("_Pragma",           BT_PRAGMA,        true),
 339   B("__STDC__",          BT_STDC,          true),
 340 };
 341 #undef B
 342
 343 struct builtin_operator
 344 {
 345   const uchar *const name;
 346   const unsigned short len;
 347   const unsigned short value;
 348 };
 349
 350 #define B(n, t)    { DSC(n), t }
 351 static const struct builtin_operator operator_array[] =
 352 {
 353   B("and",      CPP_AND_AND),
 354   B("and_eq",   CPP_AND_EQ),
 355   B("bitand",   CPP_AND),
 356   B("bitor",    CPP_OR),
 357   B("compl",    CPP_COMPL),
 358   B("not",      CPP_NOT),
 359   B("not_eq",   CPP_NOT_EQ),
 360   B("or",       CPP_OR_OR),
 361   B("or_eq",    CPP_OR_EQ),
 362   B("xor",      CPP_XOR),
 363   B("xor_eq",   CPP_XOR_EQ)
 364 };
 365 #undef B
 366
 367 /* Mark the C++ named operators in the hash table.  */
 368 static void
 369 mark_named_operators (cpp_reader *pfile)
 370 {
 371   const struct builtin_operator *b;
 372
 373   for (b = operator_array;
 374        b < (operator_array + ARRAY_SIZE (operator_array));
 375        b++)
 376     {
 377       cpp_hashnode *hp = cpp_lookup (pfile, b->name, b->len);
 378       hp->flags |= NODE_OPERATOR;
 379       hp->is_directive = 0;
 380       hp->directive_index = b->value;
 381     }
 382 }
 383
 384 void
 385 cpp_init_special_builtins (cpp_reader *pfile)
 386 {
 387   const struct builtin_macro *b;
 388   size_t n = ARRAY_SIZE (builtin_array);
 389
 390   if (CPP_OPTION (pfile, traditional))
 391     n -= 2;
 392   else if (! CPP_OPTION (pfile, stdc_0_in_system_headers)
 393            || CPP_OPTION (pfile, std))
 394     n--;
 395
 396   for (b = builtin_array; b < builtin_array + n; b++)
 397     {
 398       cpp_hashnode *hp = cpp_lookup (pfile, b->name, b->len);
 399       hp->type = NT_MACRO;
 400       hp->flags |= NODE_BUILTIN;
 401       if (b->always_warn_if_redefined
 402           || CPP_OPTION (pfile, warn_builtin_macro_redefined))
 403         hp->flags |= NODE_WARN;
 404       hp->value.builtin = (enum builtin_type) b->value;
 405     }
 406 }
 407
 408 /* Read the builtins table above and enter them, and language-specific
 409    macros, into the hash table.  HOSTED is true if this is a hosted
 410    environment.  */
 411 void
 412 cpp_init_builtins (cpp_reader *pfile, int hosted)
 413 {
 414   cpp_init_special_builtins (pfile);
 415
 416   if (!CPP_OPTION (pfile, traditional)
 417       && (! CPP_OPTION (pfile, stdc_0_in_system_headers)
 418           || CPP_OPTION (pfile, std)))
 419     _cpp_define_builtin (pfile, "__STDC__ 1");
 420
 421   if (CPP_OPTION (pfile, cplusplus))
 422     _cpp_define_builtin (pfile, "__cplusplus 1");
 423   else if (CPP_OPTION (pfile, lang) == CLK_ASM)
 424     _cpp_define_builtin (pfile, "__ASSEMBLER__ 1");
 425   else if (CPP_OPTION (pfile, lang) == CLK_STDC94)
 426     _cpp_define_builtin (pfile, "__STDC_VERSION__ 199409L");
 427   else if (CPP_OPTION (pfile, c99))
 428     _cpp_define_builtin (pfile, "__STDC_VERSION__ 199901L");
 429
 430   if (hosted)
 431     _cpp_define_builtin (pfile, "__STDC_HOSTED__ 1");
 432   else
 433     _cpp_define_builtin (pfile, "__STDC_HOSTED__ 0");
 434
 435   if (CPP_OPTION (pfile, objc))
 436     _cpp_define_builtin (pfile, "__OBJC__ 1");
 437 }
 438
 439 /* Sanity-checks are dependent on command-line options, so it is
 440    called as a subroutine of cpp_read_main_file ().  */
 441 #if ENABLE_CHECKING
 442 static void sanity_checks (cpp_reader *);
 443 static void sanity_checks (cpp_reader *pfile)
 444 {
 445   cppchar_t test = 0;
 446   size_t max_precision = 2 * CHAR_BIT * sizeof (cpp_num_part);
 447
 448   /* Sanity checks for assumptions about CPP arithmetic and target
 449      type precisions made by cpplib.  */
 450   test--;
 451   if (test < 1)
 452     cpp_error (pfile, CPP_DL_ICE, "cppchar_t must be an unsigned type");
 453
 454   if (CPP_OPTION (pfile, precision) > max_precision)
 455     cpp_error (pfile, CPP_DL_ICE,
 456                "preprocessor arithmetic has maximum precision of %lu bits;"
 457                " target requires %lu bits",
 458                (unsigned long) max_precision,
 459                (unsigned long) CPP_OPTION (pfile, precision));
 460
 461   if (CPP_OPTION (pfile, precision) < CPP_OPTION (pfile, int_precision))
 462     cpp_error (pfile, CPP_DL_ICE,
 463                "CPP arithmetic must be at least as precise as a target int");
 464
 465   if (CPP_OPTION (pfile, char_precision) < 8)
 466     cpp_error (pfile, CPP_DL_ICE, "target char is less than 8 bits wide");
 467
 468   if (CPP_OPTION (pfile, wchar_precision) < CPP_OPTION (pfile, char_precision))
 469     cpp_error (pfile, CPP_DL_ICE,
 470                "target wchar_t is narrower than target char");
 471
 472   if (CPP_OPTION (pfile, int_precision) < CPP_OPTION (pfile, char_precision))
 473     cpp_error (pfile, CPP_DL_ICE,
 474                "target int is narrower than target char");
 475
 476   /* This is assumed in eval_token() and could be fixed if necessary.  */
 477   if (sizeof (cppchar_t) > sizeof (cpp_num_part))
 478     cpp_error (pfile, CPP_DL_ICE,
 479                "CPP half-integer narrower than CPP character");
 480
 481   if (CPP_OPTION (pfile, wchar_precision) > BITS_PER_CPPCHAR_T)
 482     cpp_error (pfile, CPP_DL_ICE,
 483                "CPP on this host cannot handle wide character constants over"
 484                " %lu bits, but the target requires %lu bits",
 485                (unsigned long) BITS_PER_CPPCHAR_T,
 486                (unsigned long) CPP_OPTION (pfile, wchar_precision));
 487 }
 488 #else
 489 # define sanity_checks(PFILE)
 490 #endif
 491
 492 /* This is called after options have been parsed, and partially
 493    processed.  */
 494 void
 495 cpp_post_options (cpp_reader *pfile)
 496 {
 497   sanity_checks (pfile);
 498
 499   post_options (pfile);
 500
 501   /* Mark named operators before handling command line macros.  */
 502   if (CPP_OPTION (pfile, cplusplus) && CPP_OPTION (pfile, operator_names))
 503     mark_named_operators (pfile);
 504 }
 505
 506 /* Setup for processing input from the file named FNAME, or stdin if
 507    it is the empty string.  Return the original filename
 508    on success (e.g. foo.i->foo.c), or NULL on failure.  */
 509 const char *
 510 cpp_read_main_file (cpp_reader *pfile, const char *fname)
 511 {
 512   if (CPP_OPTION (pfile, deps.style) != DEPS_NONE)
 513     {
 514       if (!pfile->deps)
 515         pfile->deps = deps_init ();
 516
 517       /* Set the default target (if there is none already).  */
 518       deps_add_default_target (pfile->deps, fname);
 519     }
 520
 521   pfile->main_file
 522     = _cpp_find_file (pfile, fname, &pfile->no_search_path, false, 0);
 523   if (_cpp_find_failed (pfile->main_file))
 524     return NULL;
 525
 526   _cpp_stack_file (pfile, pfile->main_file, false);
 527
 528   /* For foo.i, read the original filename foo.c now, for the benefit
 529      of the front ends.  */
 530   if (CPP_OPTION (pfile, preprocessed))
 531     {
 532       read_original_filename (pfile);
 533       fname = pfile->line_table->maps[pfile->line_table->used-1].to_file;
 534     }
 535   return fname;
 536 }
 537
 538 /* For preprocessed files, if the first tokens are of the form # NUM.
 539    handle the directive so we know the original file name.  This will
 540    generate file_change callbacks, which the front ends must handle
 541    appropriately given their state of initialization.  */
 542 static void
 543 read_original_filename (cpp_reader *pfile)
 544 {
 545   const cpp_token *token, *token1;
 546
 547   /* Lex ahead; if the first tokens are of the form # NUM, then
 548      process the directive, otherwise back up.  */
 549   token = _cpp_lex_direct (pfile);
 550   if (token->type == CPP_HASH)
 551     {
 552       pfile->state.in_directive = 1;
 553       token1 = _cpp_lex_direct (pfile);
 554       _cpp_backup_tokens (pfile, 1);
 555       pfile->state.in_directive = 0;
 556
 557       /* If it's a #line directive, handle it.  */
 558       if (token1->type == CPP_NUMBER)
 559         {
 560           _cpp_handle_directive (pfile, token->flags & PREV_WHITE);
 561           read_original_directory (pfile);
 562           return;
 563         }
 564     }
 565
 566   /* Backup as if nothing happened.  */
 567   _cpp_backup_tokens (pfile, 1);
 568 }
 569
 570 /* For preprocessed files, if the tokens following the first filename
 571    line is of the form # <line> "/path/name//", handle the
 572    directive so we know the original current directory.  */
 573 static void
 574 read_original_directory (cpp_reader *pfile)
 575 {
 576   const cpp_token *hash, *token;
 577
 578   /* Lex ahead; if the first tokens are of the form # NUM, then
 579      process the directive, otherwise back up.  */
 580   hash = _cpp_lex_direct (pfile);
 581   if (hash->type != CPP_HASH)
 582     {
 583       _cpp_backup_tokens (pfile, 1);
 584       return;
 585     }
 586
 587   token = _cpp_lex_direct (pfile);
 588
 589   if (token->type != CPP_NUMBER)
 590     {
 591       _cpp_backup_tokens (pfile, 2);
 592       return;
 593     }
 594
 595   token = _cpp_lex_direct (pfile);
 596
 597   if (token->type != CPP_STRING
 598       || ! (token->val.str.len >= 5
 599             && token->val.str.text[token->val.str.len-2] == '/'
 600             && token->val.str.text[token->val.str.len-3] == '/'))
 601     {
 602       _cpp_backup_tokens (pfile, 3);
 603       return;
 604     }
 605
 606   if (pfile->cb.dir_change)
 607     {
 608       char *debugdir = (char *) alloca (token->val.str.len - 3);
 609
 610       memcpy (debugdir, (const char *) token->val.str.text + 1,
 611               token->val.str.len - 4);
 612       debugdir[token->val.str.len - 4] = '\0';
 613
 614       pfile->cb.dir_change (pfile, debugdir);
 615     }
 616 }
 617
 618 /* This is called at the end of preprocessing.  It pops the last
 619    buffer and writes dependency output.
 620
 621    Maybe it should also reset state, such that you could call
 622    cpp_start_read with a new filename to restart processing.  */
 623 void
 624 cpp_finish (cpp_reader *pfile, FILE *deps_stream)
 625 {
 626   /* Warn about unused macros before popping the final buffer.  */
 627   if (CPP_OPTION (pfile, warn_unused_macros))
 628     cpp_forall_identifiers (pfile, _cpp_warn_if_unused_macro, NULL);
 629
 630   /* lex.c leaves the final buffer on the stack.  This it so that
 631      it returns an unending stream of CPP_EOFs to the client.  If we
 632      popped the buffer, we'd dereference a NULL buffer pointer and
 633      segfault.  It's nice to allow the client to do worry-free excess
 634      cpp_get_token calls.  */
 635   while (pfile->buffer)
 636     _cpp_pop_buffer (pfile);
 637
 638   if (CPP_OPTION (pfile, deps.style) != DEPS_NONE
 639       && deps_stream)
 640     {
 641       deps_write (pfile->deps, deps_stream, 72);
 642
 643       if (CPP_OPTION (pfile, deps.phony_targets))
 644         deps_phony_targets (pfile->deps, deps_stream);
 645     }
 646
 647   /* Report on headers that could use multiple include guards.  */
 648   if (CPP_OPTION (pfile, print_include_names))
 649     _cpp_report_missing_guards (pfile);
 650 }
 651
 652 static void
 653 post_options (cpp_reader *pfile)
 654 {
 655   /* -Wtraditional is not useful in C++ mode.  */
 656   if (CPP_OPTION (pfile, cplusplus))
 657     CPP_OPTION (pfile, warn_traditional) = 0;
 658
 659   /* Permanently disable macro expansion if we are rescanning
 660      preprocessed text.  Read preprocesed source in ISO mode.  */
 661   if (CPP_OPTION (pfile, preprocessed))
 662     {
 663       if (!CPP_OPTION (pfile, directives_only))
 664         pfile->state.prevent_expansion = 1;
 665       CPP_OPTION (pfile, traditional) = 0;
 666     }
 667
 668   if (CPP_OPTION (pfile, warn_trigraphs) == 2)
 669     CPP_OPTION (pfile, warn_trigraphs) = !CPP_OPTION (pfile, trigraphs);
 670
 671   if (CPP_OPTION (pfile, traditional))
 672     {
 673       CPP_OPTION (pfile, cplusplus_comments) = 0;
 674
 675       /* Traditional CPP does not accurately track column information.  */
 676       CPP_OPTION (pfile, show_column) = 0;
 677       CPP_OPTION (pfile, trigraphs) = 0;
 678       CPP_OPTION (pfile, warn_trigraphs) = 0;
 679     }
 680 }