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, 2010, 2011 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 3, 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; see the file COPYING3.  If not see
  21 <http://www.gnu.org/licenses/>.  */
  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 #include "filenames.h"
  30
  31 static void init_library (void);
  32 static void mark_named_operators (cpp_reader *, int);
  33 static void read_original_filename (cpp_reader *);
  34 static void read_original_directory (cpp_reader *);
  35 static void post_options (cpp_reader *);
  36
  37 /* If we have designated initializers (GCC >2.7) these tables can be
  38    initialized, constant data.  Otherwise, they have to be filled in at
  39    runtime.  */
  40 #if HAVE_DESIGNATED_INITIALIZERS
  41
  42 #define init_trigraph_map()  /* Nothing.  */
  43 #define TRIGRAPH_MAP \
  44 __extension__ const uchar _cpp_trigraph_map[UCHAR_MAX + 1] = {
  45
  46 #define END };
  47 #define s(p, v) [p] = v,
  48
  49 #else
  50
  51 #define TRIGRAPH_MAP uchar _cpp_trigraph_map[UCHAR_MAX + 1] = { 0 }; \
  52  static void init_trigraph_map (void) { \
  53  unsigned char *x = _cpp_trigraph_map;
  54
  55 #define END }
  56 #define s(p, v) x[p] = v;
  57
  58 #endif
  59
  60 TRIGRAPH_MAP
  61   s('=', '#')   s(')', ']')     s('!', '|')
  62   s('(', '[')   s('\'', '^')    s('>', '}')
  63   s('/', '\\')  s('<', '{')     s('-', '~')
  64 END
  65
  66 #undef s
  67 #undef END
  68 #undef TRIGRAPH_MAP
  69
  70 /* A set of booleans indicating what CPP features each source language
  71    requires.  */
  72 struct lang_flags
  73 {
  74   char c99;
  75   char cplusplus;
  76   char extended_numbers;
  77   char extended_identifiers;
  78   char std;
  79   char cplusplus_comments;
  80   char digraphs;
  81   char uliterals;
  82   char rliterals;
  83 };
  84
  85 static const struct lang_flags lang_defaults[] =
  86 { /*              c99 c++ xnum xid std  //   digr ulit rlit */
  87   /* GNUC89   */  { 0,  0,  1,   0,  0,   1,   1,   0,   0 },
  88   /* GNUC99   */  { 1,  0,  1,   0,  0,   1,   1,   1,   1 },
  89   /* GNUC1X   */  { 1,  0,  1,   0,  0,   1,   1,   1,   1 },
  90   /* STDC89   */  { 0,  0,  0,   0,  1,   0,   0,   0,   0 },
  91   /* STDC94   */  { 0,  0,  0,   0,  1,   0,   1,   0,   0 },
  92   /* STDC99   */  { 1,  0,  1,   0,  1,   1,   1,   0,   0 },
  93   /* STDC1X   */  { 1,  0,  1,   0,  1,   1,   1,   1,   0 },
  94   /* GNUCXX   */  { 0,  1,  1,   0,  0,   1,   1,   0,   0 },
  95   /* CXX98    */  { 0,  1,  1,   0,  1,   1,   1,   0,   0 },
  96   /* GNUCXX0X */  { 1,  1,  1,   0,  0,   1,   1,   1,   1 },
  97   /* CXX0X    */  { 1,  1,  1,   0,  1,   1,   1,   1,   1 },
  98   /* ASM      */  { 0,  0,  1,   0,  0,   1,   0,   0,   0 }
  99   /* xid should be 1 for GNUC99, STDC99, GNUCXX, CXX98, GNUCXX0X, and
 100      CXX0X when no longer experimental (when all uses of identifiers
 101      in the compiler have been audited for correct handling of
 102      extended identifiers).  */
 103 };
 104
 105 /* Sets internal flags correctly for a given language.  */
 106 void
 107 cpp_set_lang (cpp_reader *pfile, enum c_lang lang)
 108 {
 109   const struct lang_flags *l = &lang_defaults[(int) lang];
 110
 111   CPP_OPTION (pfile, lang) = lang;
 112
 113   CPP_OPTION (pfile, c99)                        = l->c99;
 114   CPP_OPTION (pfile, cplusplus)                  = l->cplusplus;
 115   CPP_OPTION (pfile, extended_numbers)           = l->extended_numbers;
 116   CPP_OPTION (pfile, extended_identifiers)       = l->extended_identifiers;
 117   CPP_OPTION (pfile, std)                        = l->std;
 118   CPP_OPTION (pfile, trigraphs)                  = l->std;
 119   CPP_OPTION (pfile, cplusplus_comments)         = l->cplusplus_comments;
 120   CPP_OPTION (pfile, digraphs)                   = l->digraphs;
 121   CPP_OPTION (pfile, uliterals)                  = l->uliterals;
 122   CPP_OPTION (pfile, rliterals)                  = l->rliterals;
 123 }
 124
 125 /* Initialize library global state.  */
 126 static void
 127 init_library (void)
 128 {
 129   static int initialized = 0;
 130
 131   if (! initialized)
 132     {
 133       initialized = 1;
 134
 135       /* Set up the trigraph map.  This doesn't need to do anything if
 136          we were compiled with a compiler that supports C99 designated
 137          initializers.  */
 138       init_trigraph_map ();
 139
 140 #ifdef ENABLE_NLS
 141        (void) bindtextdomain (PACKAGE, LOCALEDIR);
 142 #endif
 143     }
 144 }
 145
 146 /* Initialize a cpp_reader structure.  */
 147 cpp_reader *
 148 cpp_create_reader (enum c_lang lang, hash_table *table,
 149                    struct line_maps *line_table)
 150 {
 151   cpp_reader *pfile;
 152
 153   /* Initialize this instance of the library if it hasn't been already.  */
 154   init_library ();
 155
 156   pfile = XCNEW (cpp_reader);
 157
 158   cpp_set_lang (pfile, lang);
 159   CPP_OPTION (pfile, warn_multichar) = 1;
 160   CPP_OPTION (pfile, discard_comments) = 1;
 161   CPP_OPTION (pfile, discard_comments_in_macro_exp) = 1;
 162   CPP_OPTION (pfile, tabstop) = 8;
 163   CPP_OPTION (pfile, operator_names) = 1;
 164   CPP_OPTION (pfile, warn_trigraphs) = 2;
 165   CPP_OPTION (pfile, warn_endif_labels) = 1;
 166   CPP_OPTION (pfile, cpp_warn_deprecated) = 1;
 167   CPP_OPTION (pfile, cpp_warn_long_long) = 0;
 168   CPP_OPTION (pfile, dollars_in_ident) = 1;
 169   CPP_OPTION (pfile, warn_dollars) = 1;
 170   CPP_OPTION (pfile, warn_variadic_macros) = 1;
 171   CPP_OPTION (pfile, warn_builtin_macro_redefined) = 1;
 172   CPP_OPTION (pfile, warn_normalize) = normalized_C;
 173
 174   /* Default CPP arithmetic to something sensible for the host for the
 175      benefit of dumb users like fix-header.  */
 176   CPP_OPTION (pfile, precision) = CHAR_BIT * sizeof (long);
 177   CPP_OPTION (pfile, char_precision) = CHAR_BIT;
 178   CPP_OPTION (pfile, wchar_precision) = CHAR_BIT * sizeof (int);
 179   CPP_OPTION (pfile, int_precision) = CHAR_BIT * sizeof (int);
 180   CPP_OPTION (pfile, unsigned_char) = 0;
 181   CPP_OPTION (pfile, unsigned_wchar) = 1;
 182   CPP_OPTION (pfile, bytes_big_endian) = 1;  /* does not matter */
 183
 184   /* Default to no charset conversion.  */
 185   CPP_OPTION (pfile, narrow_charset) = _cpp_default_encoding ();
 186   CPP_OPTION (pfile, wide_charset) = 0;
 187
 188   /* Default the input character set to UTF-8.  */
 189   CPP_OPTION (pfile, input_charset) = _cpp_default_encoding ();
 190
 191   /* A fake empty "directory" used as the starting point for files
 192      looked up without a search path.  Name cannot be '/' because we
 193      don't want to prepend anything at all to filenames using it.  All
 194      other entries are correct zero-initialized.  */
 195   pfile->no_search_path.name = (char *) "";
 196
 197   /* Initialize the line map.  */
 198   pfile->line_table = line_table;
 199
 200   /* Initialize lexer state.  */
 201   pfile->state.save_comments = ! CPP_OPTION (pfile, discard_comments);
 202
 203   /* Set up static tokens.  */
 204   pfile->avoid_paste.type = CPP_PADDING;
 205   pfile->avoid_paste.val.source = NULL;
 206   pfile->eof.type = CPP_EOF;
 207   pfile->eof.flags = 0;
 208
 209   /* Create a token buffer for the lexer.  */
 210   _cpp_init_tokenrun (&pfile->base_run, 250);
 211   pfile->cur_run = &pfile->base_run;
 212   pfile->cur_token = pfile->base_run.base;
 213
 214   /* Initialize the base context.  */
 215   pfile->context = &pfile->base_context;
 216   pfile->base_context.macro = 0;
 217   pfile->base_context.prev = pfile->base_context.next = 0;
 218
 219   /* Aligned and unaligned storage.  */
 220   pfile->a_buff = _cpp_get_buff (pfile, 0);
 221   pfile->u_buff = _cpp_get_buff (pfile, 0);
 222
 223   /* Initialize table for push_macro/pop_macro.  */
 224   pfile->pushed_macros = 0;
 225
 226   /* The expression parser stack.  */
 227   _cpp_expand_op_stack (pfile);
 228
 229   /* Initialize the buffer obstack.  */
 230   _obstack_begin (&pfile->buffer_ob, 0, 0,
 231                   (void *(*) (long)) xmalloc,
 232                   (void (*) (void *)) free);
 233
 234   _cpp_init_files (pfile);
 235
 236   _cpp_init_hashtable (pfile, table);
 237
 238   return pfile;
 239 }
 240
 241 /* Set the line_table entry in PFILE.  This is called after reading a
 242    PCH file, as the old line_table will be incorrect.  */
 243 void
 244 cpp_set_line_map (cpp_reader *pfile, struct line_maps *line_table)
 245 {
 246   pfile->line_table = line_table;
 247 }
 248
 249 /* Free resources used by PFILE.  Accessing PFILE after this function
 250    returns leads to undefined behavior.  Returns the error count.  */
 251 void
 252 cpp_destroy (cpp_reader *pfile)
 253 {
 254   cpp_context *context, *contextn;
 255   struct def_pragma_macro *pmacro;
 256   tokenrun *run, *runn;
 257   int i;
 258
 259   free (pfile->op_stack);
 260
 261   while (CPP_BUFFER (pfile) != NULL)
 262     _cpp_pop_buffer (pfile);
 263
 264   free (pfile->out.base);
 265
 266   if (pfile->macro_buffer)
 267     {
 268       free (pfile->macro_buffer);
 269       pfile->macro_buffer = NULL;
 270       pfile->macro_buffer_len = 0;
 271     }
 272
 273   if (pfile->deps)
 274     deps_free (pfile->deps);
 275   obstack_free (&pfile->buffer_ob, 0);
 276
 277   _cpp_destroy_hashtable (pfile);
 278   _cpp_cleanup_files (pfile);
 279   _cpp_destroy_iconv (pfile);
 280
 281   _cpp_free_buff (pfile->a_buff);
 282   _cpp_free_buff (pfile->u_buff);
 283   _cpp_free_buff (pfile->free_buffs);
 284
 285   for (run = &pfile->base_run; run; run = runn)
 286     {
 287       runn = run->next;
 288       free (run->base);
 289       if (run != &pfile->base_run)
 290         free (run);
 291     }
 292
 293   for (context = pfile->base_context.next; context; context = contextn)
 294     {
 295       contextn = context->next;
 296       free (context);
 297     }
 298
 299   if (pfile->comments.entries)
 300     {
 301       for (i = 0; i < pfile->comments.count; i++)
 302         free (pfile->comments.entries[i].comment);
 303
 304       free (pfile->comments.entries);
 305     }
 306   if (pfile->pushed_macros)
 307     {
 308       do
 309         {
 310           pmacro = pfile->pushed_macros;
 311           pfile->pushed_macros = pmacro->next;
 312           free (pmacro->name);
 313           free (pmacro);
 314         }
 315       while (pfile->pushed_macros);
 316     }
 317
 318   free (pfile);
 319 }
 320
 321 /* This structure defines one built-in identifier.  A node will be
 322    entered in the hash table under the name NAME, with value VALUE.
 323
 324    There are two tables of these.  builtin_array holds all the
 325    "builtin" macros: these are handled by builtin_macro() in
 326    macro.c.  Builtin is somewhat of a misnomer -- the property of
 327    interest is that these macros require special code to compute their
 328    expansions.  The value is a "cpp_builtin_type" enumerator.
 329
 330    operator_array holds the C++ named operators.  These are keywords
 331    which act as aliases for punctuators.  In C++, they cannot be
 332    altered through #define, and #if recognizes them as operators.  In
 333    C, these are not entered into the hash table at all (but see
 334    <iso646.h>).  The value is a token-type enumerator.  */
 335 struct builtin_macro
 336 {
 337   const uchar *const name;
 338   const unsigned short len;
 339   const unsigned short value;
 340   const bool always_warn_if_redefined;
 341 };
 342
 343 #define B(n, t, f)    { DSC(n), t, f }
 344 static const struct builtin_macro builtin_array[] =
 345 {
 346   B("__TIMESTAMP__",     BT_TIMESTAMP,     false),
 347   B("__TIME__",          BT_TIME,          false),
 348   B("__DATE__",          BT_DATE,          false),
 349   B("__FILE__",          BT_FILE,          false),
 350   B("__BASE_FILE__",     BT_BASE_FILE,     false),
 351   B("__LINE__",          BT_SPECLINE,      true),
 352   B("__INCLUDE_LEVEL__", BT_INCLUDE_LEVEL, true),
 353   B("__COUNTER__",       BT_COUNTER,       true),
 354   /* Keep builtins not used for -traditional-cpp at the end, and
 355      update init_builtins() if any more are added.  */
 356   B("_Pragma",           BT_PRAGMA,        true),
 357   B("__STDC__",          BT_STDC,          true),
 358 };
 359 #undef B
 360
 361 struct builtin_operator
 362 {
 363   const uchar *const name;
 364   const unsigned short len;
 365   const unsigned short value;
 366 };
 367
 368 #define B(n, t)    { DSC(n), t }
 369 static const struct builtin_operator operator_array[] =
 370 {
 371   B("and",      CPP_AND_AND),
 372   B("and_eq",   CPP_AND_EQ),
 373   B("bitand",   CPP_AND),
 374   B("bitor",    CPP_OR),
 375   B("compl",    CPP_COMPL),
 376   B("not",      CPP_NOT),
 377   B("not_eq",   CPP_NOT_EQ),
 378   B("or",       CPP_OR_OR),
 379   B("or_eq",    CPP_OR_EQ),
 380   B("xor",      CPP_XOR),
 381   B("xor_eq",   CPP_XOR_EQ)
 382 };
 383 #undef B
 384
 385 /* Mark the C++ named operators in the hash table.  */
 386 static void
 387 mark_named_operators (cpp_reader *pfile, int flags)
 388 {
 389   const struct builtin_operator *b;
 390
 391   for (b = operator_array;
 392        b < (operator_array + ARRAY_SIZE (operator_array));
 393        b++)
 394     {
 395       cpp_hashnode *hp = cpp_lookup (pfile, b->name, b->len);
 396       hp->flags |= flags;
 397       hp->is_directive = 0;
 398       hp->directive_index = b->value;
 399     }
 400 }
 401
 402 /* Helper function of cpp_type2name. Return the string associated with
 403    named operator TYPE.  */
 404 const char *
 405 cpp_named_operator2name (enum cpp_ttype type)
 406 {
 407   const struct builtin_operator *b;
 408
 409   for (b = operator_array;
 410        b < (operator_array + ARRAY_SIZE (operator_array));
 411        b++)
 412     {
 413       if (type == b->value)
 414         return (const char *) b->name;
 415     }
 416
 417   return NULL;
 418 }
 419
 420 void
 421 cpp_init_special_builtins (cpp_reader *pfile)
 422 {
 423   const struct builtin_macro *b;
 424   size_t n = ARRAY_SIZE (builtin_array);
 425
 426   if (CPP_OPTION (pfile, traditional))
 427     n -= 2;
 428   else if (! CPP_OPTION (pfile, stdc_0_in_system_headers)
 429            || CPP_OPTION (pfile, std))
 430     n--;
 431
 432   for (b = builtin_array; b < builtin_array + n; b++)
 433     {
 434       cpp_hashnode *hp = cpp_lookup (pfile, b->name, b->len);
 435       hp->type = NT_MACRO;
 436       hp->flags |= NODE_BUILTIN;
 437       if (b->always_warn_if_redefined
 438           || CPP_OPTION (pfile, warn_builtin_macro_redefined))
 439         hp->flags |= NODE_WARN;
 440       hp->value.builtin = (enum cpp_builtin_type) b->value;
 441     }
 442 }
 443
 444 /* Read the builtins table above and enter them, and language-specific
 445    macros, into the hash table.  HOSTED is true if this is a hosted
 446    environment.  */
 447 void
 448 cpp_init_builtins (cpp_reader *pfile, int hosted)
 449 {
 450   cpp_init_special_builtins (pfile);
 451
 452   if (!CPP_OPTION (pfile, traditional)
 453       && (! CPP_OPTION (pfile, stdc_0_in_system_headers)
 454           || CPP_OPTION (pfile, std)))
 455     _cpp_define_builtin (pfile, "__STDC__ 1");
 456
 457   if (CPP_OPTION (pfile, cplusplus))
 458     _cpp_define_builtin (pfile, "__cplusplus 199711L");
 459   else if (CPP_OPTION (pfile, lang) == CLK_ASM)
 460     _cpp_define_builtin (pfile, "__ASSEMBLER__ 1");
 461   else if (CPP_OPTION (pfile, lang) == CLK_STDC94)
 462     _cpp_define_builtin (pfile, "__STDC_VERSION__ 199409L");
 463   else if (CPP_OPTION (pfile, lang) == CLK_STDC1X
 464            || CPP_OPTION (pfile, lang) == CLK_GNUC1X)
 465     _cpp_define_builtin (pfile, "__STDC_VERSION__ 201000L");
 466   else if (CPP_OPTION (pfile, c99))
 467     _cpp_define_builtin (pfile, "__STDC_VERSION__ 199901L");
 468
 469   if (CPP_OPTION (pfile, uliterals)
 470       && !CPP_OPTION (pfile, cplusplus))
 471     {
 472       _cpp_define_builtin (pfile, "__STDC_UTF_16__ 1");
 473       _cpp_define_builtin (pfile, "__STDC_UTF_32__ 1");
 474     }
 475
 476   if (hosted)
 477     _cpp_define_builtin (pfile, "__STDC_HOSTED__ 1");
 478   else
 479     _cpp_define_builtin (pfile, "__STDC_HOSTED__ 0");
 480
 481   if (CPP_OPTION (pfile, objc))
 482     _cpp_define_builtin (pfile, "__OBJC__ 1");
 483 }
 484
 485 /* Sanity-checks are dependent on command-line options, so it is
 486    called as a subroutine of cpp_read_main_file ().  */
 487 #if ENABLE_CHECKING
 488 static void sanity_checks (cpp_reader *);
 489 static void sanity_checks (cpp_reader *pfile)
 490 {
 491   cppchar_t test = 0;
 492   size_t max_precision = 2 * CHAR_BIT * sizeof (cpp_num_part);
 493
 494   /* Sanity checks for assumptions about CPP arithmetic and target
 495      type precisions made by cpplib.  */
 496   test--;
 497   if (test < 1)
 498     cpp_error (pfile, CPP_DL_ICE, "cppchar_t must be an unsigned type");
 499
 500   if (CPP_OPTION (pfile, precision) > max_precision)
 501     cpp_error (pfile, CPP_DL_ICE,
 502                "preprocessor arithmetic has maximum precision of %lu bits;"
 503                " target requires %lu bits",
 504                (unsigned long) max_precision,
 505                (unsigned long) CPP_OPTION (pfile, precision));
 506
 507   if (CPP_OPTION (pfile, precision) < CPP_OPTION (pfile, int_precision))
 508     cpp_error (pfile, CPP_DL_ICE,
 509                "CPP arithmetic must be at least as precise as a target int");
 510
 511   if (CPP_OPTION (pfile, char_precision) < 8)
 512     cpp_error (pfile, CPP_DL_ICE, "target char is less than 8 bits wide");
 513
 514   if (CPP_OPTION (pfile, wchar_precision) < CPP_OPTION (pfile, char_precision))
 515     cpp_error (pfile, CPP_DL_ICE,
 516                "target wchar_t is narrower than target char");
 517
 518   if (CPP_OPTION (pfile, int_precision) < CPP_OPTION (pfile, char_precision))
 519     cpp_error (pfile, CPP_DL_ICE,
 520                "target int is narrower than target char");
 521
 522   /* This is assumed in eval_token() and could be fixed if necessary.  */
 523   if (sizeof (cppchar_t) > sizeof (cpp_num_part))
 524     cpp_error (pfile, CPP_DL_ICE,
 525                "CPP half-integer narrower than CPP character");
 526
 527   if (CPP_OPTION (pfile, wchar_precision) > BITS_PER_CPPCHAR_T)
 528     cpp_error (pfile, CPP_DL_ICE,
 529                "CPP on this host cannot handle wide character constants over"
 530                " %lu bits, but the target requires %lu bits",
 531                (unsigned long) BITS_PER_CPPCHAR_T,
 532                (unsigned long) CPP_OPTION (pfile, wchar_precision));
 533 }
 534 #else
 535 # define sanity_checks(PFILE)
 536 #endif
 537
 538 /* This is called after options have been parsed, and partially
 539    processed.  */
 540 void
 541 cpp_post_options (cpp_reader *pfile)
 542 {
 543   int flags;
 544
 545   sanity_checks (pfile);
 546
 547   post_options (pfile);
 548
 549   /* Mark named operators before handling command line macros.  */
 550   flags = 0;
 551   if (CPP_OPTION (pfile, cplusplus) && CPP_OPTION (pfile, operator_names))
 552     flags |= NODE_OPERATOR;
 553   if (CPP_OPTION (pfile, warn_cxx_operator_names))
 554     flags |= NODE_DIAGNOSTIC | NODE_WARN_OPERATOR;
 555   if (flags != 0)
 556     mark_named_operators (pfile, flags);
 557 }
 558
 559 /* Setup for processing input from the file named FNAME, or stdin if
 560    it is the empty string.  Return the original filename
 561    on success (e.g. foo.i->foo.c), or NULL on failure.  */
 562 const char *
 563 cpp_read_main_file (cpp_reader *pfile, const char *fname)
 564 {
 565   if (CPP_OPTION (pfile, deps.style) != DEPS_NONE)
 566     {
 567       if (!pfile->deps)
 568         pfile->deps = deps_init ();
 569
 570       /* Set the default target (if there is none already).  */
 571       deps_add_default_target (pfile->deps, fname);
 572     }
 573
 574   pfile->main_file
 575     = _cpp_find_file (pfile, fname, &pfile->no_search_path, false, 0);
 576   if (_cpp_find_failed (pfile->main_file))
 577     return NULL;
 578
 579   _cpp_stack_file (pfile, pfile->main_file, false);
 580
 581   /* For foo.i, read the original filename foo.c now, for the benefit
 582      of the front ends.  */
 583   if (CPP_OPTION (pfile, preprocessed))
 584     {
 585       read_original_filename (pfile);
 586       fname = pfile->line_table->maps[pfile->line_table->used-1].to_file;
 587     }
 588   return fname;
 589 }
 590
 591 /* For preprocessed files, if the first tokens are of the form # NUM.
 592    handle the directive so we know the original file name.  This will
 593    generate file_change callbacks, which the front ends must handle
 594    appropriately given their state of initialization.  */
 595 static void
 596 read_original_filename (cpp_reader *pfile)
 597 {
 598   const cpp_token *token, *token1;
 599
 600   /* Lex ahead; if the first tokens are of the form # NUM, then
 601      process the directive, otherwise back up.  */
 602   token = _cpp_lex_direct (pfile);
 603   if (token->type == CPP_HASH)
 604     {
 605       pfile->state.in_directive = 1;
 606       token1 = _cpp_lex_direct (pfile);
 607       _cpp_backup_tokens (pfile, 1);
 608       pfile->state.in_directive = 0;
 609
 610       /* If it's a #line directive, handle it.  */
 611       if (token1->type == CPP_NUMBER
 612           && _cpp_handle_directive (pfile, token->flags & PREV_WHITE))
 613         {
 614           read_original_directory (pfile);
 615           return;
 616         }
 617     }
 618
 619   /* Backup as if nothing happened.  */
 620   _cpp_backup_tokens (pfile, 1);
 621 }
 622
 623 /* For preprocessed files, if the tokens following the first filename
 624    line is of the form # <line> "/path/name//", handle the
 625    directive so we know the original current directory.  */
 626 static void
 627 read_original_directory (cpp_reader *pfile)
 628 {
 629   const cpp_token *hash, *token;
 630
 631   /* Lex ahead; if the first tokens are of the form # NUM, then
 632      process the directive, otherwise back up.  */
 633   hash = _cpp_lex_direct (pfile);
 634   if (hash->type != CPP_HASH)
 635     {
 636       _cpp_backup_tokens (pfile, 1);
 637       return;
 638     }
 639
 640   token = _cpp_lex_direct (pfile);
 641
 642   if (token->type != CPP_NUMBER)
 643     {
 644       _cpp_backup_tokens (pfile, 2);
 645       return;
 646     }
 647
 648   token = _cpp_lex_direct (pfile);
 649
 650   if (token->type != CPP_STRING
 651       || ! (token->val.str.len >= 5
 652             && IS_DIR_SEPARATOR (token->val.str.text[token->val.str.len-2])
 653             && IS_DIR_SEPARATOR (token->val.str.text[token->val.str.len-3])))
 654     {
 655       _cpp_backup_tokens (pfile, 3);
 656       return;
 657     }
 658
 659   if (pfile->cb.dir_change)
 660     {
 661       char *debugdir = (char *) alloca (token->val.str.len - 3);
 662
 663       memcpy (debugdir, (const char *) token->val.str.text + 1,
 664               token->val.str.len - 4);
 665       debugdir[token->val.str.len - 4] = '\0';
 666
 667       pfile->cb.dir_change (pfile, debugdir);
 668     }
 669 }
 670
 671 /* This is called at the end of preprocessing.  It pops the last
 672    buffer and writes dependency output.
 673
 674    Maybe it should also reset state, such that you could call
 675    cpp_start_read with a new filename to restart processing.  */
 676 void
 677 cpp_finish (cpp_reader *pfile, FILE *deps_stream)
 678 {
 679   /* Warn about unused macros before popping the final buffer.  */
 680   if (CPP_OPTION (pfile, warn_unused_macros))
 681     cpp_forall_identifiers (pfile, _cpp_warn_if_unused_macro, NULL);
 682
 683   /* lex.c leaves the final buffer on the stack.  This it so that
 684      it returns an unending stream of CPP_EOFs to the client.  If we
 685      popped the buffer, we'd dereference a NULL buffer pointer and
 686      segfault.  It's nice to allow the client to do worry-free excess
 687      cpp_get_token calls.  */
 688   while (pfile->buffer)
 689     _cpp_pop_buffer (pfile);
 690
 691   if (CPP_OPTION (pfile, deps.style) != DEPS_NONE
 692       && deps_stream)
 693     {
 694       deps_write (pfile->deps, deps_stream, 72);
 695
 696       if (CPP_OPTION (pfile, deps.phony_targets))
 697         deps_phony_targets (pfile->deps, deps_stream);
 698     }
 699
 700   /* Report on headers that could use multiple include guards.  */
 701   if (CPP_OPTION (pfile, print_include_names))
 702     _cpp_report_missing_guards (pfile);
 703 }
 704
 705 static void
 706 post_options (cpp_reader *pfile)
 707 {
 708   /* -Wtraditional is not useful in C++ mode.  */
 709   if (CPP_OPTION (pfile, cplusplus))
 710     CPP_OPTION (pfile, cpp_warn_traditional) = 0;
 711
 712   /* Permanently disable macro expansion if we are rescanning
 713      preprocessed text.  Read preprocesed source in ISO mode.  */
 714   if (CPP_OPTION (pfile, preprocessed))
 715     {
 716       if (!CPP_OPTION (pfile, directives_only))
 717         pfile->state.prevent_expansion = 1;
 718       CPP_OPTION (pfile, traditional) = 0;
 719     }
 720
 721   if (CPP_OPTION (pfile, warn_trigraphs) == 2)
 722     CPP_OPTION (pfile, warn_trigraphs) = !CPP_OPTION (pfile, trigraphs);
 723
 724   if (CPP_OPTION (pfile, traditional))
 725     {
 726       CPP_OPTION (pfile, cplusplus_comments) = 0;
 727
 728       CPP_OPTION (pfile, trigraphs) = 0;
 729       CPP_OPTION (pfile, warn_trigraphs) = 0;
 730     }
 731 }