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, 2012 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 #ifndef ENABLE_CANONICAL_SYSTEM_HEADERS
  32 #define ENABLE_CANONICAL_SYSTEM_HEADERS 0
  33 #endif
  34
  35 static void init_library (void);
  36 static void mark_named_operators (cpp_reader *, int);
  37 static void read_original_filename (cpp_reader *);
  38 static void read_original_directory (cpp_reader *);
  39 static void post_options (cpp_reader *);
  40
  41 /* If we have designated initializers (GCC >2.7) these tables can be
  42    initialized, constant data.  Otherwise, they have to be filled in at
  43    runtime.  */
  44 #if HAVE_DESIGNATED_INITIALIZERS
  45
  46 #define init_trigraph_map()  /* Nothing.  */
  47 #define TRIGRAPH_MAP \
  48 __extension__ const uchar _cpp_trigraph_map[UCHAR_MAX + 1] = {
  49
  50 #define END };
  51 #define s(p, v) [p] = v,
  52
  53 #else
  54
  55 #define TRIGRAPH_MAP uchar _cpp_trigraph_map[UCHAR_MAX + 1] = { 0 }; \
  56  static void init_trigraph_map (void) { \
  57  unsigned char *x = _cpp_trigraph_map;
  58
  59 #define END }
  60 #define s(p, v) x[p] = v;
  61
  62 #endif
  63
  64 TRIGRAPH_MAP
  65   s('=', '#')   s(')', ']')     s('!', '|')
  66   s('(', '[')   s('\'', '^')    s('>', '}')
  67   s('/', '\\')  s('<', '{')     s('-', '~')
  68 END
  69
  70 #undef s
  71 #undef END
  72 #undef TRIGRAPH_MAP
  73
  74 /* A set of booleans indicating what CPP features each source language
  75    requires.  */
  76 struct lang_flags
  77 {
  78   char c99;
  79   char cplusplus;
  80   char extended_numbers;
  81   char extended_identifiers;
  82   char std;
  83   char cplusplus_comments;
  84   char digraphs;
  85   char uliterals;
  86   char rliterals;
  87   char user_literals;
  88 };
  89
  90 static const struct lang_flags lang_defaults[] =
  91 { /*              c99 c++ xnum xid std  //   digr ulit rlit user_literals */
  92   /* GNUC89   */  { 0,  0,  1,   0,  0,   1,   1,   0,   0,    0 },
  93   /* GNUC99   */  { 1,  0,  1,   0,  0,   1,   1,   1,   1,    0 },
  94   /* GNUC11   */  { 1,  0,  1,   0,  0,   1,   1,   1,   1,    0 },
  95   /* STDC89   */  { 0,  0,  0,   0,  1,   0,   0,   0,   0,    0 },
  96   /* STDC94   */  { 0,  0,  0,   0,  1,   0,   1,   0,   0,    0 },
  97   /* STDC99   */  { 1,  0,  1,   0,  1,   1,   1,   0,   0,    0 },
  98   /* STDC11   */  { 1,  0,  1,   0,  1,   1,   1,   1,   0,    0 },
  99   /* GNUCXX   */  { 0,  1,  1,   0,  0,   1,   1,   0,   0,    0 },
 100   /* CXX98    */  { 0,  1,  1,   0,  1,   1,   1,   0,   0,    0 },
 101   /* GNUCXX11 */  { 1,  1,  1,   0,  0,   1,   1,   1,   1,    1 },
 102   /* CXX11    */  { 1,  1,  1,   0,  1,   1,   1,   1,   1,    1 },
 103   /* ASM      */  { 0,  0,  1,   0,  0,   1,   0,   0,   0,    0 }
 104   /* xid should be 1 for GNUC99, STDC99, GNUCXX, CXX98, GNUCXX11, and
 105      CXX11 when no longer experimental (when all uses of identifiers
 106      in the compiler have been audited for correct handling of
 107      extended identifiers).  */
 108 };
 109
 110 /* Sets internal flags correctly for a given language.  */
 111 void
 112 cpp_set_lang (cpp_reader *pfile, enum c_lang lang)
 113 {
 114   const struct lang_flags *l = &lang_defaults[(int) lang];
 115
 116   CPP_OPTION (pfile, lang) = lang;
 117
 118   CPP_OPTION (pfile, c99)                        = l->c99;
 119   CPP_OPTION (pfile, cplusplus)                  = l->cplusplus;
 120   CPP_OPTION (pfile, extended_numbers)           = l->extended_numbers;
 121   CPP_OPTION (pfile, extended_identifiers)       = l->extended_identifiers;
 122   CPP_OPTION (pfile, std)                        = l->std;
 123   CPP_OPTION (pfile, trigraphs)                  = l->std;
 124   CPP_OPTION (pfile, cplusplus_comments)         = l->cplusplus_comments;
 125   CPP_OPTION (pfile, digraphs)                   = l->digraphs;
 126   CPP_OPTION (pfile, uliterals)                  = l->uliterals;
 127   CPP_OPTION (pfile, rliterals)                  = l->rliterals;
 128   CPP_OPTION (pfile, user_literals)              = l->user_literals;
 129 }
 130
 131 /* Initialize library global state.  */
 132 static void
 133 init_library (void)
 134 {
 135   static int initialized = 0;
 136
 137   if (! initialized)
 138     {
 139       initialized = 1;
 140
 141       _cpp_init_lexer ();
 142
 143       /* Set up the trigraph map.  This doesn't need to do anything if
 144          we were compiled with a compiler that supports C99 designated
 145          initializers.  */
 146       init_trigraph_map ();
 147
 148 #ifdef ENABLE_NLS
 149        (void) bindtextdomain (PACKAGE, LOCALEDIR);
 150 #endif
 151     }
 152 }
 153
 154 /* Initialize a cpp_reader structure.  */
 155 cpp_reader *
 156 cpp_create_reader (enum c_lang lang, cpp_hash_table *table,
 157                    struct line_maps *line_table)
 158 {
 159   cpp_reader *pfile;
 160
 161   /* Initialize this instance of the library if it hasn't been already.  */
 162   init_library ();
 163
 164   pfile = XCNEW (cpp_reader);
 165   memset (&pfile->base_context, 0, sizeof (pfile->base_context));
 166
 167   cpp_set_lang (pfile, lang);
 168   CPP_OPTION (pfile, warn_multichar) = 1;
 169   CPP_OPTION (pfile, discard_comments) = 1;
 170   CPP_OPTION (pfile, discard_comments_in_macro_exp) = 1;
 171   CPP_OPTION (pfile, tabstop) = 8;
 172   CPP_OPTION (pfile, operator_names) = 1;
 173   CPP_OPTION (pfile, warn_trigraphs) = 2;
 174   CPP_OPTION (pfile, warn_endif_labels) = 1;
 175   CPP_OPTION (pfile, cpp_warn_deprecated) = 1;
 176   CPP_OPTION (pfile, cpp_warn_long_long) = 0;
 177   CPP_OPTION (pfile, dollars_in_ident) = 1;
 178   CPP_OPTION (pfile, warn_dollars) = 1;
 179   CPP_OPTION (pfile, warn_variadic_macros) = 1;
 180   CPP_OPTION (pfile, warn_builtin_macro_redefined) = 1;
 181   /* By default, track locations of tokens resulting from macro
 182      expansion.  The '2' means, track the locations with the highest
 183      accuracy.  Read the comments for struct
 184      cpp_options::track_macro_expansion to learn about the other
 185      values.  */
 186   CPP_OPTION (pfile, track_macro_expansion) = 2;
 187   CPP_OPTION (pfile, warn_normalize) = normalized_C;
 188   CPP_OPTION (pfile, warn_literal_suffix) = 1;
 189   CPP_OPTION (pfile, canonical_system_headers)
 190       = ENABLE_CANONICAL_SYSTEM_HEADERS;
 191   CPP_OPTION (pfile, ext_numeric_literals) = 1;
 192
 193   /* Default CPP arithmetic to something sensible for the host for the
 194      benefit of dumb users like fix-header.  */
 195   CPP_OPTION (pfile, precision) = CHAR_BIT * sizeof (long);
 196   CPP_OPTION (pfile, char_precision) = CHAR_BIT;
 197   CPP_OPTION (pfile, wchar_precision) = CHAR_BIT * sizeof (int);
 198   CPP_OPTION (pfile, int_precision) = CHAR_BIT * sizeof (int);
 199   CPP_OPTION (pfile, unsigned_char) = 0;
 200   CPP_OPTION (pfile, unsigned_wchar) = 1;
 201   CPP_OPTION (pfile, bytes_big_endian) = 1;  /* does not matter */
 202
 203   /* Default to no charset conversion.  */
 204   CPP_OPTION (pfile, narrow_charset) = _cpp_default_encoding ();
 205   CPP_OPTION (pfile, wide_charset) = 0;
 206
 207   /* Default the input character set to UTF-8.  */
 208   CPP_OPTION (pfile, input_charset) = _cpp_default_encoding ();
 209
 210   /* A fake empty "directory" used as the starting point for files
 211      looked up without a search path.  Name cannot be '/' because we
 212      don't want to prepend anything at all to filenames using it.  All
 213      other entries are correct zero-initialized.  */
 214   pfile->no_search_path.name = (char *) "";
 215
 216   /* Initialize the line map.  */
 217   pfile->line_table = line_table;
 218
 219   /* Initialize lexer state.  */
 220   pfile->state.save_comments = ! CPP_OPTION (pfile, discard_comments);
 221
 222   /* Set up static tokens.  */
 223   pfile->avoid_paste.type = CPP_PADDING;
 224   pfile->avoid_paste.val.source = NULL;
 225   pfile->eof.type = CPP_EOF;
 226   pfile->eof.flags = 0;
 227
 228   /* Create a token buffer for the lexer.  */
 229   _cpp_init_tokenrun (&pfile->base_run, 250);
 230   pfile->cur_run = &pfile->base_run;
 231   pfile->cur_token = pfile->base_run.base;
 232
 233   /* Initialize the base context.  */
 234   pfile->context = &pfile->base_context;
 235   pfile->base_context.c.macro = 0;
 236   pfile->base_context.prev = pfile->base_context.next = 0;
 237
 238   /* Aligned and unaligned storage.  */
 239   pfile->a_buff = _cpp_get_buff (pfile, 0);
 240   pfile->u_buff = _cpp_get_buff (pfile, 0);
 241
 242   /* Initialize table for push_macro/pop_macro.  */
 243   pfile->pushed_macros = 0;
 244
 245   /* Do not force token locations by default.  */
 246   pfile->forced_token_location_p = NULL;
 247
 248   /* The expression parser stack.  */
 249   _cpp_expand_op_stack (pfile);
 250
 251   /* Initialize the buffer obstack.  */
 252   _obstack_begin (&pfile->buffer_ob, 0, 0,
 253                   (void *(*) (long)) xmalloc,
 254                   (void (*) (void *)) free);
 255
 256   _cpp_init_files (pfile);
 257
 258   _cpp_init_hashtable (pfile, table);
 259
 260   return pfile;
 261 }
 262
 263 /* Set the line_table entry in PFILE.  This is called after reading a
 264    PCH file, as the old line_table will be incorrect.  */
 265 void
 266 cpp_set_line_map (cpp_reader *pfile, struct line_maps *line_table)
 267 {
 268   pfile->line_table = line_table;
 269 }
 270
 271 /* Free resources used by PFILE.  Accessing PFILE after this function
 272    returns leads to undefined behavior.  Returns the error count.  */
 273 void
 274 cpp_destroy (cpp_reader *pfile)
 275 {
 276   cpp_context *context, *contextn;
 277   struct def_pragma_macro *pmacro;
 278   tokenrun *run, *runn;
 279   int i;
 280
 281   free (pfile->op_stack);
 282
 283   while (CPP_BUFFER (pfile) != NULL)
 284     _cpp_pop_buffer (pfile);
 285
 286   free (pfile->out.base);
 287
 288   if (pfile->macro_buffer)
 289     {
 290       free (pfile->macro_buffer);
 291       pfile->macro_buffer = NULL;
 292       pfile->macro_buffer_len = 0;
 293     }
 294
 295   if (pfile->deps)
 296     deps_free (pfile->deps);
 297   obstack_free (&pfile->buffer_ob, 0);
 298
 299   _cpp_destroy_hashtable (pfile);
 300   _cpp_cleanup_files (pfile);
 301   _cpp_destroy_iconv (pfile);
 302
 303   _cpp_free_buff (pfile->a_buff);
 304   _cpp_free_buff (pfile->u_buff);
 305   _cpp_free_buff (pfile->free_buffs);
 306
 307   for (run = &pfile->base_run; run; run = runn)
 308     {
 309       runn = run->next;
 310       free (run->base);
 311       if (run != &pfile->base_run)
 312         free (run);
 313     }
 314
 315   for (context = pfile->base_context.next; context; context = contextn)
 316     {
 317       contextn = context->next;
 318       free (context);
 319     }
 320
 321   if (pfile->comments.entries)
 322     {
 323       for (i = 0; i < pfile->comments.count; i++)
 324         free (pfile->comments.entries[i].comment);
 325
 326       free (pfile->comments.entries);
 327     }
 328   if (pfile->pushed_macros)
 329     {
 330       do
 331         {
 332           pmacro = pfile->pushed_macros;
 333           pfile->pushed_macros = pmacro->next;
 334           free (pmacro->name);
 335           free (pmacro);
 336         }
 337       while (pfile->pushed_macros);
 338     }
 339
 340   free (pfile);
 341 }
 342
 343 /* This structure defines one built-in identifier.  A node will be
 344    entered in the hash table under the name NAME, with value VALUE.
 345
 346    There are two tables of these.  builtin_array holds all the
 347    "builtin" macros: these are handled by builtin_macro() in
 348    macro.c.  Builtin is somewhat of a misnomer -- the property of
 349    interest is that these macros require special code to compute their
 350    expansions.  The value is a "cpp_builtin_type" enumerator.
 351
 352    operator_array holds the C++ named operators.  These are keywords
 353    which act as aliases for punctuators.  In C++, they cannot be
 354    altered through #define, and #if recognizes them as operators.  In
 355    C, these are not entered into the hash table at all (but see
 356    <iso646.h>).  The value is a token-type enumerator.  */
 357 struct builtin_macro
 358 {
 359   const uchar *const name;
 360   const unsigned short len;
 361   const unsigned short value;
 362   const bool always_warn_if_redefined;
 363 };
 364
 365 #define B(n, t, f)    { DSC(n), t, f }
 366 static const struct builtin_macro builtin_array[] =
 367 {
 368   B("__TIMESTAMP__",     BT_TIMESTAMP,     false),
 369   B("__TIME__",          BT_TIME,          false),
 370   B("__DATE__",          BT_DATE,          false),
 371   B("__FILE__",          BT_FILE,          false),
 372   B("__BASE_FILE__",     BT_BASE_FILE,     false),
 373   B("__LINE__",          BT_SPECLINE,      true),
 374   B("__INCLUDE_LEVEL__", BT_INCLUDE_LEVEL, true),
 375   B("__COUNTER__",       BT_COUNTER,       true),
 376   /* Keep builtins not used for -traditional-cpp at the end, and
 377      update init_builtins() if any more are added.  */
 378   B("_Pragma",           BT_PRAGMA,        true),
 379   B("__STDC__",          BT_STDC,          true),
 380 };
 381 #undef B
 382
 383 struct builtin_operator
 384 {
 385   const uchar *const name;
 386   const unsigned short len;
 387   const unsigned short value;
 388 };
 389
 390 #define B(n, t)    { DSC(n), t }
 391 static const struct builtin_operator operator_array[] =
 392 {
 393   B("and",      CPP_AND_AND),
 394   B("and_eq",   CPP_AND_EQ),
 395   B("bitand",   CPP_AND),
 396   B("bitor",    CPP_OR),
 397   B("compl",    CPP_COMPL),
 398   B("not",      CPP_NOT),
 399   B("not_eq",   CPP_NOT_EQ),
 400   B("or",       CPP_OR_OR),
 401   B("or_eq",    CPP_OR_EQ),
 402   B("xor",      CPP_XOR),
 403   B("xor_eq",   CPP_XOR_EQ)
 404 };
 405 #undef B
 406
 407 /* Mark the C++ named operators in the hash table.  */
 408 static void
 409 mark_named_operators (cpp_reader *pfile, int flags)
 410 {
 411   const struct builtin_operator *b;
 412
 413   for (b = operator_array;
 414        b < (operator_array + ARRAY_SIZE (operator_array));
 415        b++)
 416     {
 417       cpp_hashnode *hp = cpp_lookup (pfile, b->name, b->len);
 418       hp->flags |= flags;
 419       hp->is_directive = 0;
 420       hp->directive_index = b->value;
 421     }
 422 }
 423
 424 /* Helper function of cpp_type2name. Return the string associated with
 425    named operator TYPE.  */
 426 const char *
 427 cpp_named_operator2name (enum cpp_ttype type)
 428 {
 429   const struct builtin_operator *b;
 430
 431   for (b = operator_array;
 432        b < (operator_array + ARRAY_SIZE (operator_array));
 433        b++)
 434     {
 435       if (type == b->value)
 436         return (const char *) b->name;
 437     }
 438
 439   return NULL;
 440 }
 441
 442 void
 443 cpp_init_special_builtins (cpp_reader *pfile)
 444 {
 445   const struct builtin_macro *b;
 446   size_t n = ARRAY_SIZE (builtin_array);
 447
 448   if (CPP_OPTION (pfile, traditional))
 449     n -= 2;
 450   else if (! CPP_OPTION (pfile, stdc_0_in_system_headers)
 451            || CPP_OPTION (pfile, std))
 452     n--;
 453
 454   for (b = builtin_array; b < builtin_array + n; b++)
 455     {
 456       cpp_hashnode *hp = cpp_lookup (pfile, b->name, b->len);
 457       hp->type = NT_MACRO;
 458       hp->flags |= NODE_BUILTIN;
 459       if (b->always_warn_if_redefined
 460           || CPP_OPTION (pfile, warn_builtin_macro_redefined))
 461         hp->flags |= NODE_WARN;
 462       hp->value.builtin = (enum cpp_builtin_type) b->value;
 463     }
 464 }
 465
 466 /* Read the builtins table above and enter them, and language-specific
 467    macros, into the hash table.  HOSTED is true if this is a hosted
 468    environment.  */
 469 void
 470 cpp_init_builtins (cpp_reader *pfile, int hosted)
 471 {
 472   cpp_init_special_builtins (pfile);
 473
 474   if (!CPP_OPTION (pfile, traditional)
 475       && (! CPP_OPTION (pfile, stdc_0_in_system_headers)
 476           || CPP_OPTION (pfile, std)))
 477     _cpp_define_builtin (pfile, "__STDC__ 1");
 478
 479   if (CPP_OPTION (pfile, cplusplus))
 480     {
 481       if (CPP_OPTION (pfile, lang) == CLK_CXX11
 482            || CPP_OPTION (pfile, lang) == CLK_GNUCXX11)
 483         _cpp_define_builtin (pfile, "__cplusplus 201103L");
 484       else
 485         _cpp_define_builtin (pfile, "__cplusplus 199711L");
 486     }
 487   else if (CPP_OPTION (pfile, lang) == CLK_ASM)
 488     _cpp_define_builtin (pfile, "__ASSEMBLER__ 1");
 489   else if (CPP_OPTION (pfile, lang) == CLK_STDC94)
 490     _cpp_define_builtin (pfile, "__STDC_VERSION__ 199409L");
 491   else if (CPP_OPTION (pfile, lang) == CLK_STDC11
 492            || CPP_OPTION (pfile, lang) == CLK_GNUC11)
 493     _cpp_define_builtin (pfile, "__STDC_VERSION__ 201112L");
 494   else if (CPP_OPTION (pfile, c99))
 495     _cpp_define_builtin (pfile, "__STDC_VERSION__ 199901L");
 496
 497   if (CPP_OPTION (pfile, uliterals)
 498       && !CPP_OPTION (pfile, cplusplus))
 499     {
 500       _cpp_define_builtin (pfile, "__STDC_UTF_16__ 1");
 501       _cpp_define_builtin (pfile, "__STDC_UTF_32__ 1");
 502     }
 503
 504   if (hosted)
 505     _cpp_define_builtin (pfile, "__STDC_HOSTED__ 1");
 506   else
 507     _cpp_define_builtin (pfile, "__STDC_HOSTED__ 0");
 508
 509   if (CPP_OPTION (pfile, objc))
 510     _cpp_define_builtin (pfile, "__OBJC__ 1");
 511 }
 512
 513 /* Sanity-checks are dependent on command-line options, so it is
 514    called as a subroutine of cpp_read_main_file ().  */
 515 #if ENABLE_CHECKING
 516 static void sanity_checks (cpp_reader *);
 517 static void sanity_checks (cpp_reader *pfile)
 518 {
 519   cppchar_t test = 0;
 520   size_t max_precision = 2 * CHAR_BIT * sizeof (cpp_num_part);
 521
 522   /* Sanity checks for assumptions about CPP arithmetic and target
 523      type precisions made by cpplib.  */
 524   test--;
 525   if (test < 1)
 526     cpp_error (pfile, CPP_DL_ICE, "cppchar_t must be an unsigned type");
 527
 528   if (CPP_OPTION (pfile, precision) > max_precision)
 529     cpp_error (pfile, CPP_DL_ICE,
 530                "preprocessor arithmetic has maximum precision of %lu bits;"
 531                " target requires %lu bits",
 532                (unsigned long) max_precision,
 533                (unsigned long) CPP_OPTION (pfile, precision));
 534
 535   if (CPP_OPTION (pfile, precision) < CPP_OPTION (pfile, int_precision))
 536     cpp_error (pfile, CPP_DL_ICE,
 537                "CPP arithmetic must be at least as precise as a target int");
 538
 539   if (CPP_OPTION (pfile, char_precision) < 8)
 540     cpp_error (pfile, CPP_DL_ICE, "target char is less than 8 bits wide");
 541
 542   if (CPP_OPTION (pfile, wchar_precision) < CPP_OPTION (pfile, char_precision))
 543     cpp_error (pfile, CPP_DL_ICE,
 544                "target wchar_t is narrower than target char");
 545
 546   if (CPP_OPTION (pfile, int_precision) < CPP_OPTION (pfile, char_precision))
 547     cpp_error (pfile, CPP_DL_ICE,
 548                "target int is narrower than target char");
 549
 550   /* This is assumed in eval_token() and could be fixed if necessary.  */
 551   if (sizeof (cppchar_t) > sizeof (cpp_num_part))
 552     cpp_error (pfile, CPP_DL_ICE,
 553                "CPP half-integer narrower than CPP character");
 554
 555   if (CPP_OPTION (pfile, wchar_precision) > BITS_PER_CPPCHAR_T)
 556     cpp_error (pfile, CPP_DL_ICE,
 557                "CPP on this host cannot handle wide character constants over"
 558                " %lu bits, but the target requires %lu bits",
 559                (unsigned long) BITS_PER_CPPCHAR_T,
 560                (unsigned long) CPP_OPTION (pfile, wchar_precision));
 561 }
 562 #else
 563 # define sanity_checks(PFILE)
 564 #endif
 565
 566 /* This is called after options have been parsed, and partially
 567    processed.  */
 568 void
 569 cpp_post_options (cpp_reader *pfile)
 570 {
 571   int flags;
 572
 573   sanity_checks (pfile);
 574
 575   post_options (pfile);
 576
 577   /* Mark named operators before handling command line macros.  */
 578   flags = 0;
 579   if (CPP_OPTION (pfile, cplusplus) && CPP_OPTION (pfile, operator_names))
 580     flags |= NODE_OPERATOR;
 581   if (CPP_OPTION (pfile, warn_cxx_operator_names))
 582     flags |= NODE_DIAGNOSTIC | NODE_WARN_OPERATOR;
 583   if (flags != 0)
 584     mark_named_operators (pfile, flags);
 585 }
 586
 587 /* Setup for processing input from the file named FNAME, or stdin if
 588    it is the empty string.  Return the original filename
 589    on success (e.g. foo.i->foo.c), or NULL on failure.  */
 590 const char *
 591 cpp_read_main_file (cpp_reader *pfile, const char *fname)
 592 {
 593   if (CPP_OPTION (pfile, deps.style) != DEPS_NONE)
 594     {
 595       if (!pfile->deps)
 596         pfile->deps = deps_init ();
 597
 598       /* Set the default target (if there is none already).  */
 599       deps_add_default_target (pfile->deps, fname);
 600     }
 601
 602   pfile->main_file
 603     = _cpp_find_file (pfile, fname, &pfile->no_search_path, false, 0, false);
 604   if (_cpp_find_failed (pfile->main_file))
 605     return NULL;
 606
 607   _cpp_stack_file (pfile, pfile->main_file, false);
 608
 609   /* For foo.i, read the original filename foo.c now, for the benefit
 610      of the front ends.  */
 611   if (CPP_OPTION (pfile, preprocessed))
 612     {
 613       read_original_filename (pfile);
 614       fname =
 615         ORDINARY_MAP_FILE_NAME
 616         ((LINEMAPS_LAST_ORDINARY_MAP (pfile->line_table)));
 617     }
 618   return fname;
 619 }
 620
 621 /* For preprocessed files, if the first tokens are of the form # NUM.
 622    handle the directive so we know the original file name.  This will
 623    generate file_change callbacks, which the front ends must handle
 624    appropriately given their state of initialization.  */
 625 static void
 626 read_original_filename (cpp_reader *pfile)
 627 {
 628   const cpp_token *token, *token1;
 629
 630   /* Lex ahead; if the first tokens are of the form # NUM, then
 631      process the directive, otherwise back up.  */
 632   token = _cpp_lex_direct (pfile);
 633   if (token->type == CPP_HASH)
 634     {
 635       pfile->state.in_directive = 1;
 636       token1 = _cpp_lex_direct (pfile);
 637       _cpp_backup_tokens (pfile, 1);
 638       pfile->state.in_directive = 0;
 639
 640       /* If it's a #line directive, handle it.  */
 641       if (token1->type == CPP_NUMBER
 642           && _cpp_handle_directive (pfile, token->flags & PREV_WHITE))
 643         {
 644           read_original_directory (pfile);
 645           return;
 646         }
 647     }
 648
 649   /* Backup as if nothing happened.  */
 650   _cpp_backup_tokens (pfile, 1);
 651 }
 652
 653 /* For preprocessed files, if the tokens following the first filename
 654    line is of the form # <line> "/path/name//", handle the
 655    directive so we know the original current directory.  */
 656 static void
 657 read_original_directory (cpp_reader *pfile)
 658 {
 659   const cpp_token *hash, *token;
 660
 661   /* Lex ahead; if the first tokens are of the form # NUM, then
 662      process the directive, otherwise back up.  */
 663   hash = _cpp_lex_direct (pfile);
 664   if (hash->type != CPP_HASH)
 665     {
 666       _cpp_backup_tokens (pfile, 1);
 667       return;
 668     }
 669
 670   token = _cpp_lex_direct (pfile);
 671
 672   if (token->type != CPP_NUMBER)
 673     {
 674       _cpp_backup_tokens (pfile, 2);
 675       return;
 676     }
 677
 678   token = _cpp_lex_direct (pfile);
 679
 680   if (token->type != CPP_STRING
 681       || ! (token->val.str.len >= 5
 682             && IS_DIR_SEPARATOR (token->val.str.text[token->val.str.len-2])
 683             && IS_DIR_SEPARATOR (token->val.str.text[token->val.str.len-3])))
 684     {
 685       _cpp_backup_tokens (pfile, 3);
 686       return;
 687     }
 688
 689   if (pfile->cb.dir_change)
 690     {
 691       char *debugdir = (char *) alloca (token->val.str.len - 3);
 692
 693       memcpy (debugdir, (const char *) token->val.str.text + 1,
 694               token->val.str.len - 4);
 695       debugdir[token->val.str.len - 4] = '\0';
 696
 697       pfile->cb.dir_change (pfile, debugdir);
 698     }
 699 }
 700
 701 /* This is called at the end of preprocessing.  It pops the last
 702    buffer and writes dependency output.
 703
 704    Maybe it should also reset state, such that you could call
 705    cpp_start_read with a new filename to restart processing.  */
 706 void
 707 cpp_finish (cpp_reader *pfile, FILE *deps_stream)
 708 {
 709   /* Warn about unused macros before popping the final buffer.  */
 710   if (CPP_OPTION (pfile, warn_unused_macros))
 711     cpp_forall_identifiers (pfile, _cpp_warn_if_unused_macro, NULL);
 712
 713   /* lex.c leaves the final buffer on the stack.  This it so that
 714      it returns an unending stream of CPP_EOFs to the client.  If we
 715      popped the buffer, we'd dereference a NULL buffer pointer and
 716      segfault.  It's nice to allow the client to do worry-free excess
 717      cpp_get_token calls.  */
 718   while (pfile->buffer)
 719     _cpp_pop_buffer (pfile);
 720
 721   if (CPP_OPTION (pfile, deps.style) != DEPS_NONE
 722       && deps_stream)
 723     {
 724       deps_write (pfile->deps, deps_stream, 72);
 725
 726       if (CPP_OPTION (pfile, deps.phony_targets))
 727         deps_phony_targets (pfile->deps, deps_stream);
 728     }
 729
 730   /* Report on headers that could use multiple include guards.  */
 731   if (CPP_OPTION (pfile, print_include_names))
 732     _cpp_report_missing_guards (pfile);
 733 }
 734
 735 static void
 736 post_options (cpp_reader *pfile)
 737 {
 738   /* -Wtraditional is not useful in C++ mode.  */
 739   if (CPP_OPTION (pfile, cplusplus))
 740     CPP_OPTION (pfile, cpp_warn_traditional) = 0;
 741
 742   /* Permanently disable macro expansion if we are rescanning
 743      preprocessed text.  Read preprocesed source in ISO mode.  */
 744   if (CPP_OPTION (pfile, preprocessed))
 745     {
 746       if (!CPP_OPTION (pfile, directives_only))
 747         pfile->state.prevent_expansion = 1;
 748       CPP_OPTION (pfile, traditional) = 0;
 749     }
 750
 751   if (CPP_OPTION (pfile, warn_trigraphs) == 2)
 752     CPP_OPTION (pfile, warn_trigraphs) = !CPP_OPTION (pfile, trigraphs);
 753
 754   if (CPP_OPTION (pfile, traditional))
 755     {
 756       CPP_OPTION (pfile, cplusplus_comments) = 0;
 757
 758       CPP_OPTION (pfile, trigraphs) = 0;
 759       CPP_OPTION (pfile, warn_trigraphs) = 0;
 760     }
 761 }