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   char user_literals;
  84 };
  85
  86 static const struct lang_flags lang_defaults[] =
  87 { /*              c99 c++ xnum xid std  //   digr ulit rlit user_literals */
  88   /* GNUC89   */  { 0,  0,  1,   0,  0,   1,   1,   0,   0,    0 },
  89   /* GNUC99   */  { 1,  0,  1,   0,  0,   1,   1,   1,   1,    0 },
  90   /* GNUC11   */  { 1,  0,  1,   0,  0,   1,   1,   1,   1,    0 },
  91   /* STDC89   */  { 0,  0,  0,   0,  1,   0,   0,   0,   0,    0 },
  92   /* STDC94   */  { 0,  0,  0,   0,  1,   0,   1,   0,   0,    0 },
  93   /* STDC99   */  { 1,  0,  1,   0,  1,   1,   1,   0,   0,    0 },
  94   /* STDC11   */  { 1,  0,  1,   0,  1,   1,   1,   1,   0,    0 },
  95   /* GNUCXX   */  { 0,  1,  1,   0,  0,   1,   1,   0,   0,    0 },
  96   /* CXX98    */  { 0,  1,  1,   0,  1,   1,   1,   0,   0,    0 },
  97   /* GNUCXX11 */  { 1,  1,  1,   0,  0,   1,   1,   1,   1,    1 },
  98   /* CXX11    */  { 1,  1,  1,   0,  1,   1,   1,   1,   1,    1 },
  99   /* ASM      */  { 0,  0,  1,   0,  0,   1,   0,   0,   0,    0 }
 100   /* xid should be 1 for GNUC99, STDC99, GNUCXX, CXX98, GNUCXX11, and
 101      CXX11 when no longer experimental (when all uses of identifiers
 102      in the compiler have been audited for correct handling of
 103      extended identifiers).  */
 104 };
 105
 106 /* Sets internal flags correctly for a given language.  */
 107 void
 108 cpp_set_lang (cpp_reader *pfile, enum c_lang lang)
 109 {
 110   const struct lang_flags *l = &lang_defaults[(int) lang];
 111
 112   CPP_OPTION (pfile, lang) = lang;
 113
 114   CPP_OPTION (pfile, c99)                        = l->c99;
 115   CPP_OPTION (pfile, cplusplus)                  = l->cplusplus;
 116   CPP_OPTION (pfile, extended_numbers)           = l->extended_numbers;
 117   CPP_OPTION (pfile, extended_identifiers)       = l->extended_identifiers;
 118   CPP_OPTION (pfile, std)                        = l->std;
 119   CPP_OPTION (pfile, trigraphs)                  = l->std;
 120   CPP_OPTION (pfile, cplusplus_comments)         = l->cplusplus_comments;
 121   CPP_OPTION (pfile, digraphs)                   = l->digraphs;
 122   CPP_OPTION (pfile, uliterals)                  = l->uliterals;
 123   CPP_OPTION (pfile, rliterals)                  = l->rliterals;
 124   CPP_OPTION (pfile, user_literals)              = l->user_literals;
 125 }
 126
 127 /* Initialize library global state.  */
 128 static void
 129 init_library (void)
 130 {
 131   static int initialized = 0;
 132
 133   if (! initialized)
 134     {
 135       initialized = 1;
 136
 137       _cpp_init_lexer ();
 138
 139       /* Set up the trigraph map.  This doesn't need to do anything if
 140          we were compiled with a compiler that supports C99 designated
 141          initializers.  */
 142       init_trigraph_map ();
 143
 144 #ifdef ENABLE_NLS
 145        (void) bindtextdomain (PACKAGE, LOCALEDIR);
 146 #endif
 147     }
 148 }
 149
 150 /* Initialize a cpp_reader structure.  */
 151 cpp_reader *
 152 cpp_create_reader (enum c_lang lang, hash_table *table,
 153                    struct line_maps *line_table)
 154 {
 155   cpp_reader *pfile;
 156
 157   /* Initialize this instance of the library if it hasn't been already.  */
 158   init_library ();
 159
 160   pfile = XCNEW (cpp_reader);
 161   memset (&pfile->base_context, 0, sizeof (pfile->base_context));
 162
 163   cpp_set_lang (pfile, lang);
 164   CPP_OPTION (pfile, warn_multichar) = 1;
 165   CPP_OPTION (pfile, discard_comments) = 1;
 166   CPP_OPTION (pfile, discard_comments_in_macro_exp) = 1;
 167   CPP_OPTION (pfile, tabstop) = 8;
 168   CPP_OPTION (pfile, operator_names) = 1;
 169   CPP_OPTION (pfile, warn_trigraphs) = 2;
 170   CPP_OPTION (pfile, warn_endif_labels) = 1;
 171   CPP_OPTION (pfile, cpp_warn_deprecated) = 1;
 172   CPP_OPTION (pfile, cpp_warn_long_long) = 0;
 173   CPP_OPTION (pfile, dollars_in_ident) = 1;
 174   CPP_OPTION (pfile, warn_dollars) = 1;
 175   CPP_OPTION (pfile, warn_variadic_macros) = 1;
 176   CPP_OPTION (pfile, warn_builtin_macro_redefined) = 1;
 177   CPP_OPTION (pfile, warn_normalize) = normalized_C;
 178
 179   /* Default CPP arithmetic to something sensible for the host for the
 180      benefit of dumb users like fix-header.  */
 181   CPP_OPTION (pfile, precision) = CHAR_BIT * sizeof (long);
 182   CPP_OPTION (pfile, char_precision) = CHAR_BIT;
 183   CPP_OPTION (pfile, wchar_precision) = CHAR_BIT * sizeof (int);
 184   CPP_OPTION (pfile, int_precision) = CHAR_BIT * sizeof (int);
 185   CPP_OPTION (pfile, unsigned_char) = 0;
 186   CPP_OPTION (pfile, unsigned_wchar) = 1;
 187   CPP_OPTION (pfile, bytes_big_endian) = 1;  /* does not matter */
 188
 189   /* Default to no charset conversion.  */
 190   CPP_OPTION (pfile, narrow_charset) = _cpp_default_encoding ();
 191   CPP_OPTION (pfile, wide_charset) = 0;
 192
 193   /* Default the input character set to UTF-8.  */
 194   CPP_OPTION (pfile, input_charset) = _cpp_default_encoding ();
 195
 196   /* A fake empty "directory" used as the starting point for files
 197      looked up without a search path.  Name cannot be '/' because we
 198      don't want to prepend anything at all to filenames using it.  All
 199      other entries are correct zero-initialized.  */
 200   pfile->no_search_path.name = (char *) "";
 201
 202   /* Initialize the line map.  */
 203   pfile->line_table = line_table;
 204
 205   /* Initialize lexer state.  */
 206   pfile->state.save_comments = ! CPP_OPTION (pfile, discard_comments);
 207
 208   /* Set up static tokens.  */
 209   pfile->avoid_paste.type = CPP_PADDING;
 210   pfile->avoid_paste.val.source = NULL;
 211   pfile->eof.type = CPP_EOF;
 212   pfile->eof.flags = 0;
 213
 214   /* Create a token buffer for the lexer.  */
 215   _cpp_init_tokenrun (&pfile->base_run, 250);
 216   pfile->cur_run = &pfile->base_run;
 217   pfile->cur_token = pfile->base_run.base;
 218
 219   /* Initialize the base context.  */
 220   pfile->context = &pfile->base_context;
 221   pfile->base_context.c.macro = 0;
 222   pfile->base_context.prev = pfile->base_context.next = 0;
 223
 224   /* Aligned and unaligned storage.  */
 225   pfile->a_buff = _cpp_get_buff (pfile, 0);
 226   pfile->u_buff = _cpp_get_buff (pfile, 0);
 227
 228   /* Initialize table for push_macro/pop_macro.  */
 229   pfile->pushed_macros = 0;
 230
 231   /* Do not force token locations by default.  */
 232   pfile->forced_token_location_p = NULL;
 233
 234   /* The expression parser stack.  */
 235   _cpp_expand_op_stack (pfile);
 236
 237   /* Initialize the buffer obstack.  */
 238   _obstack_begin (&pfile->buffer_ob, 0, 0,
 239                   (void *(*) (long)) xmalloc,
 240                   (void (*) (void *)) free);
 241
 242   _cpp_init_files (pfile);
 243
 244   _cpp_init_hashtable (pfile, table);
 245
 246   return pfile;
 247 }
 248
 249 /* Set the line_table entry in PFILE.  This is called after reading a
 250    PCH file, as the old line_table will be incorrect.  */
 251 void
 252 cpp_set_line_map (cpp_reader *pfile, struct line_maps *line_table)
 253 {
 254   pfile->line_table = line_table;
 255 }
 256
 257 /* Free resources used by PFILE.  Accessing PFILE after this function
 258    returns leads to undefined behavior.  Returns the error count.  */
 259 void
 260 cpp_destroy (cpp_reader *pfile)
 261 {
 262   cpp_context *context, *contextn;
 263   struct def_pragma_macro *pmacro;
 264   tokenrun *run, *runn;
 265   int i;
 266
 267   free (pfile->op_stack);
 268
 269   while (CPP_BUFFER (pfile) != NULL)
 270     _cpp_pop_buffer (pfile);
 271
 272   free (pfile->out.base);
 273
 274   if (pfile->macro_buffer)
 275     {
 276       free (pfile->macro_buffer);
 277       pfile->macro_buffer = NULL;
 278       pfile->macro_buffer_len = 0;
 279     }
 280
 281   if (pfile->deps)
 282     deps_free (pfile->deps);
 283   obstack_free (&pfile->buffer_ob, 0);
 284
 285   _cpp_destroy_hashtable (pfile);
 286   _cpp_cleanup_files (pfile);
 287   _cpp_destroy_iconv (pfile);
 288
 289   _cpp_free_buff (pfile->a_buff);
 290   _cpp_free_buff (pfile->u_buff);
 291   _cpp_free_buff (pfile->free_buffs);
 292
 293   for (run = &pfile->base_run; run; run = runn)
 294     {
 295       runn = run->next;
 296       free (run->base);
 297       if (run != &pfile->base_run)
 298         free (run);
 299     }
 300
 301   for (context = pfile->base_context.next; context; context = contextn)
 302     {
 303       contextn = context->next;
 304       free (context);
 305     }
 306
 307   if (pfile->comments.entries)
 308     {
 309       for (i = 0; i < pfile->comments.count; i++)
 310         free (pfile->comments.entries[i].comment);
 311
 312       free (pfile->comments.entries);
 313     }
 314   if (pfile->pushed_macros)
 315     {
 316       do
 317         {
 318           pmacro = pfile->pushed_macros;
 319           pfile->pushed_macros = pmacro->next;
 320           free (pmacro->name);
 321           free (pmacro);
 322         }
 323       while (pfile->pushed_macros);
 324     }
 325
 326   free (pfile);
 327 }
 328
 329 /* This structure defines one built-in identifier.  A node will be
 330    entered in the hash table under the name NAME, with value VALUE.
 331
 332    There are two tables of these.  builtin_array holds all the
 333    "builtin" macros: these are handled by builtin_macro() in
 334    macro.c.  Builtin is somewhat of a misnomer -- the property of
 335    interest is that these macros require special code to compute their
 336    expansions.  The value is a "cpp_builtin_type" enumerator.
 337
 338    operator_array holds the C++ named operators.  These are keywords
 339    which act as aliases for punctuators.  In C++, they cannot be
 340    altered through #define, and #if recognizes them as operators.  In
 341    C, these are not entered into the hash table at all (but see
 342    <iso646.h>).  The value is a token-type enumerator.  */
 343 struct builtin_macro
 344 {
 345   const uchar *const name;
 346   const unsigned short len;
 347   const unsigned short value;
 348   const bool always_warn_if_redefined;
 349 };
 350
 351 #define B(n, t, f)    { DSC(n), t, f }
 352 static const struct builtin_macro builtin_array[] =
 353 {
 354   B("__TIMESTAMP__",     BT_TIMESTAMP,     false),
 355   B("__TIME__",          BT_TIME,          false),
 356   B("__DATE__",          BT_DATE,          false),
 357   B("__FILE__",          BT_FILE,          false),
 358   B("__BASE_FILE__",     BT_BASE_FILE,     false),
 359   B("__LINE__",          BT_SPECLINE,      true),
 360   B("__INCLUDE_LEVEL__", BT_INCLUDE_LEVEL, true),
 361   B("__COUNTER__",       BT_COUNTER,       true),
 362   /* Keep builtins not used for -traditional-cpp at the end, and
 363      update init_builtins() if any more are added.  */
 364   B("_Pragma",           BT_PRAGMA,        true),
 365   B("__STDC__",          BT_STDC,          true),
 366 };
 367 #undef B
 368
 369 struct builtin_operator
 370 {
 371   const uchar *const name;
 372   const unsigned short len;
 373   const unsigned short value;
 374 };
 375
 376 #define B(n, t)    { DSC(n), t }
 377 static const struct builtin_operator operator_array[] =
 378 {
 379   B("and",      CPP_AND_AND),
 380   B("and_eq",   CPP_AND_EQ),
 381   B("bitand",   CPP_AND),
 382   B("bitor",    CPP_OR),
 383   B("compl",    CPP_COMPL),
 384   B("not",      CPP_NOT),
 385   B("not_eq",   CPP_NOT_EQ),
 386   B("or",       CPP_OR_OR),
 387   B("or_eq",    CPP_OR_EQ),
 388   B("xor",      CPP_XOR),
 389   B("xor_eq",   CPP_XOR_EQ)
 390 };
 391 #undef B
 392
 393 /* Mark the C++ named operators in the hash table.  */
 394 static void
 395 mark_named_operators (cpp_reader *pfile, int flags)
 396 {
 397   const struct builtin_operator *b;
 398
 399   for (b = operator_array;
 400        b < (operator_array + ARRAY_SIZE (operator_array));
 401        b++)
 402     {
 403       cpp_hashnode *hp = cpp_lookup (pfile, b->name, b->len);
 404       hp->flags |= flags;
 405       hp->is_directive = 0;
 406       hp->directive_index = b->value;
 407     }
 408 }
 409
 410 /* Helper function of cpp_type2name. Return the string associated with
 411    named operator TYPE.  */
 412 const char *
 413 cpp_named_operator2name (enum cpp_ttype type)
 414 {
 415   const struct builtin_operator *b;
 416
 417   for (b = operator_array;
 418        b < (operator_array + ARRAY_SIZE (operator_array));
 419        b++)
 420     {
 421       if (type == b->value)
 422         return (const char *) b->name;
 423     }
 424
 425   return NULL;
 426 }
 427
 428 void
 429 cpp_init_special_builtins (cpp_reader *pfile)
 430 {
 431   const struct builtin_macro *b;
 432   size_t n = ARRAY_SIZE (builtin_array);
 433
 434   if (CPP_OPTION (pfile, traditional))
 435     n -= 2;
 436   else if (! CPP_OPTION (pfile, stdc_0_in_system_headers)
 437            || CPP_OPTION (pfile, std))
 438     n--;
 439
 440   for (b = builtin_array; b < builtin_array + n; b++)
 441     {
 442       cpp_hashnode *hp = cpp_lookup (pfile, b->name, b->len);
 443       hp->type = NT_MACRO;
 444       hp->flags |= NODE_BUILTIN;
 445       if (b->always_warn_if_redefined
 446           || CPP_OPTION (pfile, warn_builtin_macro_redefined))
 447         hp->flags |= NODE_WARN;
 448       hp->value.builtin = (enum cpp_builtin_type) b->value;
 449     }
 450 }
 451
 452 /* Read the builtins table above and enter them, and language-specific
 453    macros, into the hash table.  HOSTED is true if this is a hosted
 454    environment.  */
 455 void
 456 cpp_init_builtins (cpp_reader *pfile, int hosted)
 457 {
 458   cpp_init_special_builtins (pfile);
 459
 460   if (!CPP_OPTION (pfile, traditional)
 461       && (! CPP_OPTION (pfile, stdc_0_in_system_headers)
 462           || CPP_OPTION (pfile, std)))
 463     _cpp_define_builtin (pfile, "__STDC__ 1");
 464
 465   if (CPP_OPTION (pfile, cplusplus))
 466     {
 467       if (CPP_OPTION (pfile, lang) == CLK_CXX11
 468            || CPP_OPTION (pfile, lang) == CLK_GNUCXX11)
 469         _cpp_define_builtin (pfile, "__cplusplus 201103L");
 470       else
 471         _cpp_define_builtin (pfile, "__cplusplus 199711L");
 472     }
 473   else if (CPP_OPTION (pfile, lang) == CLK_ASM)
 474     _cpp_define_builtin (pfile, "__ASSEMBLER__ 1");
 475   else if (CPP_OPTION (pfile, lang) == CLK_STDC94)
 476     _cpp_define_builtin (pfile, "__STDC_VERSION__ 199409L");
 477   else if (CPP_OPTION (pfile, lang) == CLK_STDC11
 478            || CPP_OPTION (pfile, lang) == CLK_GNUC11)
 479     _cpp_define_builtin (pfile, "__STDC_VERSION__ 201112L");
 480   else if (CPP_OPTION (pfile, c99))
 481     _cpp_define_builtin (pfile, "__STDC_VERSION__ 199901L");
 482
 483   if (CPP_OPTION (pfile, uliterals)
 484       && !CPP_OPTION (pfile, cplusplus))
 485     {
 486       _cpp_define_builtin (pfile, "__STDC_UTF_16__ 1");
 487       _cpp_define_builtin (pfile, "__STDC_UTF_32__ 1");
 488     }
 489
 490   if (hosted)
 491     _cpp_define_builtin (pfile, "__STDC_HOSTED__ 1");
 492   else
 493     _cpp_define_builtin (pfile, "__STDC_HOSTED__ 0");
 494
 495   if (CPP_OPTION (pfile, objc))
 496     _cpp_define_builtin (pfile, "__OBJC__ 1");
 497 }
 498
 499 /* Sanity-checks are dependent on command-line options, so it is
 500    called as a subroutine of cpp_read_main_file ().  */
 501 #if ENABLE_CHECKING
 502 static void sanity_checks (cpp_reader *);
 503 static void sanity_checks (cpp_reader *pfile)
 504 {
 505   cppchar_t test = 0;
 506   size_t max_precision = 2 * CHAR_BIT * sizeof (cpp_num_part);
 507
 508   /* Sanity checks for assumptions about CPP arithmetic and target
 509      type precisions made by cpplib.  */
 510   test--;
 511   if (test < 1)
 512     cpp_error (pfile, CPP_DL_ICE, "cppchar_t must be an unsigned type");
 513
 514   if (CPP_OPTION (pfile, precision) > max_precision)
 515     cpp_error (pfile, CPP_DL_ICE,
 516                "preprocessor arithmetic has maximum precision of %lu bits;"
 517                " target requires %lu bits",
 518                (unsigned long) max_precision,
 519                (unsigned long) CPP_OPTION (pfile, precision));
 520
 521   if (CPP_OPTION (pfile, precision) < CPP_OPTION (pfile, int_precision))
 522     cpp_error (pfile, CPP_DL_ICE,
 523                "CPP arithmetic must be at least as precise as a target int");
 524
 525   if (CPP_OPTION (pfile, char_precision) < 8)
 526     cpp_error (pfile, CPP_DL_ICE, "target char is less than 8 bits wide");
 527
 528   if (CPP_OPTION (pfile, wchar_precision) < CPP_OPTION (pfile, char_precision))
 529     cpp_error (pfile, CPP_DL_ICE,
 530                "target wchar_t is narrower than target char");
 531
 532   if (CPP_OPTION (pfile, int_precision) < CPP_OPTION (pfile, char_precision))
 533     cpp_error (pfile, CPP_DL_ICE,
 534                "target int is narrower than target char");
 535
 536   /* This is assumed in eval_token() and could be fixed if necessary.  */
 537   if (sizeof (cppchar_t) > sizeof (cpp_num_part))
 538     cpp_error (pfile, CPP_DL_ICE,
 539                "CPP half-integer narrower than CPP character");
 540
 541   if (CPP_OPTION (pfile, wchar_precision) > BITS_PER_CPPCHAR_T)
 542     cpp_error (pfile, CPP_DL_ICE,
 543                "CPP on this host cannot handle wide character constants over"
 544                " %lu bits, but the target requires %lu bits",
 545                (unsigned long) BITS_PER_CPPCHAR_T,
 546                (unsigned long) CPP_OPTION (pfile, wchar_precision));
 547 }
 548 #else
 549 # define sanity_checks(PFILE)
 550 #endif
 551
 552 /* This is called after options have been parsed, and partially
 553    processed.  */
 554 void
 555 cpp_post_options (cpp_reader *pfile)
 556 {
 557   int flags;
 558
 559   sanity_checks (pfile);
 560
 561   post_options (pfile);
 562
 563   /* Mark named operators before handling command line macros.  */
 564   flags = 0;
 565   if (CPP_OPTION (pfile, cplusplus) && CPP_OPTION (pfile, operator_names))
 566     flags |= NODE_OPERATOR;
 567   if (CPP_OPTION (pfile, warn_cxx_operator_names))
 568     flags |= NODE_DIAGNOSTIC | NODE_WARN_OPERATOR;
 569   if (flags != 0)
 570     mark_named_operators (pfile, flags);
 571 }
 572
 573 /* Setup for processing input from the file named FNAME, or stdin if
 574    it is the empty string.  Return the original filename
 575    on success (e.g. foo.i->foo.c), or NULL on failure.  */
 576 const char *
 577 cpp_read_main_file (cpp_reader *pfile, const char *fname)
 578 {
 579   if (CPP_OPTION (pfile, deps.style) != DEPS_NONE)
 580     {
 581       if (!pfile->deps)
 582         pfile->deps = deps_init ();
 583
 584       /* Set the default target (if there is none already).  */
 585       deps_add_default_target (pfile->deps, fname);
 586     }
 587
 588   pfile->main_file
 589     = _cpp_find_file (pfile, fname, &pfile->no_search_path, false, 0);
 590   if (_cpp_find_failed (pfile->main_file))
 591     return NULL;
 592
 593   _cpp_stack_file (pfile, pfile->main_file, false);
 594
 595   /* For foo.i, read the original filename foo.c now, for the benefit
 596      of the front ends.  */
 597   if (CPP_OPTION (pfile, preprocessed))
 598     {
 599       read_original_filename (pfile);
 600       fname =
 601         ORDINARY_MAP_FILE_NAME
 602         ((LINEMAPS_LAST_ORDINARY_MAP (pfile->line_table)));
 603     }
 604   return fname;
 605 }
 606
 607 /* For preprocessed files, if the first tokens are of the form # NUM.
 608    handle the directive so we know the original file name.  This will
 609    generate file_change callbacks, which the front ends must handle
 610    appropriately given their state of initialization.  */
 611 static void
 612 read_original_filename (cpp_reader *pfile)
 613 {
 614   const cpp_token *token, *token1;
 615
 616   /* Lex ahead; if the first tokens are of the form # NUM, then
 617      process the directive, otherwise back up.  */
 618   token = _cpp_lex_direct (pfile);
 619   if (token->type == CPP_HASH)
 620     {
 621       pfile->state.in_directive = 1;
 622       token1 = _cpp_lex_direct (pfile);
 623       _cpp_backup_tokens (pfile, 1);
 624       pfile->state.in_directive = 0;
 625
 626       /* If it's a #line directive, handle it.  */
 627       if (token1->type == CPP_NUMBER
 628           && _cpp_handle_directive (pfile, token->flags & PREV_WHITE))
 629         {
 630           read_original_directory (pfile);
 631           return;
 632         }
 633     }
 634
 635   /* Backup as if nothing happened.  */
 636   _cpp_backup_tokens (pfile, 1);
 637 }
 638
 639 /* For preprocessed files, if the tokens following the first filename
 640    line is of the form # <line> "/path/name//", handle the
 641    directive so we know the original current directory.  */
 642 static void
 643 read_original_directory (cpp_reader *pfile)
 644 {
 645   const cpp_token *hash, *token;
 646
 647   /* Lex ahead; if the first tokens are of the form # NUM, then
 648      process the directive, otherwise back up.  */
 649   hash = _cpp_lex_direct (pfile);
 650   if (hash->type != CPP_HASH)
 651     {
 652       _cpp_backup_tokens (pfile, 1);
 653       return;
 654     }
 655
 656   token = _cpp_lex_direct (pfile);
 657
 658   if (token->type != CPP_NUMBER)
 659     {
 660       _cpp_backup_tokens (pfile, 2);
 661       return;
 662     }
 663
 664   token = _cpp_lex_direct (pfile);
 665
 666   if (token->type != CPP_STRING
 667       || ! (token->val.str.len >= 5
 668             && IS_DIR_SEPARATOR (token->val.str.text[token->val.str.len-2])
 669             && IS_DIR_SEPARATOR (token->val.str.text[token->val.str.len-3])))
 670     {
 671       _cpp_backup_tokens (pfile, 3);
 672       return;
 673     }
 674
 675   if (pfile->cb.dir_change)
 676     {
 677       char *debugdir = (char *) alloca (token->val.str.len - 3);
 678
 679       memcpy (debugdir, (const char *) token->val.str.text + 1,
 680               token->val.str.len - 4);
 681       debugdir[token->val.str.len - 4] = '\0';
 682
 683       pfile->cb.dir_change (pfile, debugdir);
 684     }
 685 }
 686
 687 /* This is called at the end of preprocessing.  It pops the last
 688    buffer and writes dependency output.
 689
 690    Maybe it should also reset state, such that you could call
 691    cpp_start_read with a new filename to restart processing.  */
 692 void
 693 cpp_finish (cpp_reader *pfile, FILE *deps_stream)
 694 {
 695   /* Warn about unused macros before popping the final buffer.  */
 696   if (CPP_OPTION (pfile, warn_unused_macros))
 697     cpp_forall_identifiers (pfile, _cpp_warn_if_unused_macro, NULL);
 698
 699   /* lex.c leaves the final buffer on the stack.  This it so that
 700      it returns an unending stream of CPP_EOFs to the client.  If we
 701      popped the buffer, we'd dereference a NULL buffer pointer and
 702      segfault.  It's nice to allow the client to do worry-free excess
 703      cpp_get_token calls.  */
 704   while (pfile->buffer)
 705     _cpp_pop_buffer (pfile);
 706
 707   if (CPP_OPTION (pfile, deps.style) != DEPS_NONE
 708       && deps_stream)
 709     {
 710       deps_write (pfile->deps, deps_stream, 72);
 711
 712       if (CPP_OPTION (pfile, deps.phony_targets))
 713         deps_phony_targets (pfile->deps, deps_stream);
 714     }
 715
 716   /* Report on headers that could use multiple include guards.  */
 717   if (CPP_OPTION (pfile, print_include_names))
 718     _cpp_report_missing_guards (pfile);
 719 }
 720
 721 static void
 722 post_options (cpp_reader *pfile)
 723 {
 724   /* -Wtraditional is not useful in C++ mode.  */
 725   if (CPP_OPTION (pfile, cplusplus))
 726     CPP_OPTION (pfile, cpp_warn_traditional) = 0;
 727
 728   /* Permanently disable macro expansion if we are rescanning
 729      preprocessed text.  Read preprocesed source in ISO mode.  */
 730   if (CPP_OPTION (pfile, preprocessed))
 731     {
 732       if (!CPP_OPTION (pfile, directives_only))
 733         pfile->state.prevent_expansion = 1;
 734       CPP_OPTION (pfile, traditional) = 0;
 735     }
 736
 737   if (CPP_OPTION (pfile, warn_trigraphs) == 2)
 738     CPP_OPTION (pfile, warn_trigraphs) = !CPP_OPTION (pfile, trigraphs);
 739
 740   if (CPP_OPTION (pfile, traditional))
 741     {
 742       CPP_OPTION (pfile, cplusplus_comments) = 0;
 743
 744       CPP_OPTION (pfile, trigraphs) = 0;
 745       CPP_OPTION (pfile, warn_trigraphs) = 0;
 746     }
 747 }