libcpp/init.c

   1 /* CPP Library.
   2    Copyright (C) 1986-2014 Free Software Foundation, Inc.
   3    Contributed by Per Bothner, 1994-95.
   4    Based on CCCP program by Paul Rubin, June 1986
   5    Adapted to ANSI C, Richard Stallman, Jan 1987
   6
   7 This program is free software; you can redistribute it and/or modify it
   8 under the terms of the GNU General Public License as published by the
   9 Free Software Foundation; either version 3, or (at your option) any
  10 later version.
  11
  12 This program is distributed in the hope that it will be useful,
  13 but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 GNU General Public License for more details.
  16
  17 You should have received a copy of the GNU General Public License
  18 along with this program; see the file COPYING3.  If not see
  19 <http://www.gnu.org/licenses/>.  */
  20
  21 #include "config.h"
  22 #include "system.h"
  23 #include "cpplib.h"
  24 #include "internal.h"
  25 #include "mkdeps.h"
  26 #include "localedir.h"
  27 #include "filenames.h"
  28
  29 #ifndef ENABLE_CANONICAL_SYSTEM_HEADERS
  30 #define ENABLE_CANONICAL_SYSTEM_HEADERS 0
  31 #endif
  32
  33 static void init_library (void);
  34 static void mark_named_operators (cpp_reader *, int);
  35 static void read_original_filename (cpp_reader *);
  36 static void read_original_directory (cpp_reader *);
  37 static void post_options (cpp_reader *);
  38
  39 /* If we have designated initializers (GCC >2.7) these tables can be
  40    initialized, constant data.  Otherwise, they have to be filled in at
  41    runtime.  */
  42 #if HAVE_DESIGNATED_INITIALIZERS
  43
  44 #define init_trigraph_map()  /* Nothing.  */
  45 #define TRIGRAPH_MAP \
  46 __extension__ const uchar _cpp_trigraph_map[UCHAR_MAX + 1] = {
  47
  48 #define END };
  49 #define s(p, v) [p] = v,
  50
  51 #else
  52
  53 #define TRIGRAPH_MAP uchar _cpp_trigraph_map[UCHAR_MAX + 1] = { 0 }; \
  54  static void init_trigraph_map (void) { \
  55  unsigned char *x = _cpp_trigraph_map;
  56
  57 #define END }
  58 #define s(p, v) x[p] = v;
  59
  60 #endif
  61
  62 TRIGRAPH_MAP
  63   s('=', '#')   s(')', ']')     s('!', '|')
  64   s('(', '[')   s('\'', '^')    s('>', '}')
  65   s('/', '\\')  s('<', '{')     s('-', '~')
  66 END
  67
  68 #undef s
  69 #undef END
  70 #undef TRIGRAPH_MAP
  71
  72 /* A set of booleans indicating what CPP features each source language
  73    requires.  */
  74 struct lang_flags
  75 {
  76   char c99;
  77   char cplusplus;
  78   char extended_numbers;
  79   char extended_identifiers;
  80   char c11_identifiers;
  81   char std;
  82   char cplusplus_comments;
  83   char digraphs;
  84   char uliterals;
  85   char rliterals;
  86   char user_literals;
  87   char binary_constants;
  88   char digit_separators;
  89 };
  90
  91 static const struct lang_flags lang_defaults[] =
  92 { /*              c99 c++ xnum xid c11 std  //   digr ulit rlit udlit bin_cst dig_sep */
  93   /* GNUC89   */  { 0,  0,  1,   0,  0,  0,   1,   1,   0,   0,   0,    0,      0 },
  94   /* GNUC99   */  { 1,  0,  1,   0,  0,  0,   1,   1,   1,   1,   0,    0,      0 },
  95   /* GNUC11   */  { 1,  0,  1,   0,  1,  0,   1,   1,   1,   1,   0,    0,      0 },
  96   /* STDC89   */  { 0,  0,  0,   0,  0,  1,   0,   0,   0,   0,   0,    0,      0 },
  97   /* STDC94   */  { 0,  0,  0,   0,  0,  1,   0,   1,   0,   0,   0,    0,      0 },
  98   /* STDC99   */  { 1,  0,  1,   0,  0,  1,   1,   1,   0,   0,   0,    0,      0 },
  99   /* STDC11   */  { 1,  0,  1,   0,  1,  1,   1,   1,   1,   0,   0,    0,      0 },
 100   /* GNUCXX   */  { 0,  1,  1,   0,  0,  0,   1,   1,   0,   0,   0,    0,      0 },
 101   /* CXX98    */  { 0,  1,  1,   0,  0,  1,   1,   1,   0,   0,   0,    0,      0 },
 102   /* GNUCXX11 */  { 1,  1,  1,   0,  1,  0,   1,   1,   1,   1,   1,    0,      0 },
 103   /* CXX11    */  { 1,  1,  1,   0,  1,  1,   1,   1,   1,   1,   1,    0,      0 },
 104   /* GNUCXX1Y */  { 1,  1,  1,   0,  1,  0,   1,   1,   1,   1,   1,    1,      1 },
 105   /* CXX1Y    */  { 1,  1,  1,   0,  1,  1,   1,   1,   1,   1,   1,    1,      1 },
 106   /* ASM      */  { 0,  0,  1,   0,  0,  0,   1,   0,   0,   0,   0,    0,      0 }
 107   /* xid should be 1 for GNUC99, STDC99, GNUCXX, CXX98, GNUCXX11, CXX11,
 108      GNUCXX1Y, and CXX1Y when no longer experimental (when all uses of
 109      identifiers in the compiler have been audited for correct handling
 110      of extended identifiers).  */
 111 };
 112
 113 /* Sets internal flags correctly for a given language.  */
 114 void
 115 cpp_set_lang (cpp_reader *pfile, enum c_lang lang)
 116 {
 117   const struct lang_flags *l = &lang_defaults[(int) lang];
 118
 119   CPP_OPTION (pfile, lang) = lang;
 120
 121   CPP_OPTION (pfile, c99)                        = l->c99;
 122   CPP_OPTION (pfile, cplusplus)                  = l->cplusplus;
 123   CPP_OPTION (pfile, extended_numbers)           = l->extended_numbers;
 124   CPP_OPTION (pfile, extended_identifiers)       = l->extended_identifiers;
 125   CPP_OPTION (pfile, c11_identifiers)            = l->c11_identifiers;
 126   CPP_OPTION (pfile, std)                        = l->std;
 127   CPP_OPTION (pfile, trigraphs)                  = l->std;
 128   CPP_OPTION (pfile, cplusplus_comments)         = l->cplusplus_comments;
 129   CPP_OPTION (pfile, digraphs)                   = l->digraphs;
 130   CPP_OPTION (pfile, uliterals)                  = l->uliterals;
 131   CPP_OPTION (pfile, rliterals)                  = l->rliterals;
 132   CPP_OPTION (pfile, user_literals)              = l->user_literals;
 133   CPP_OPTION (pfile, binary_constants)           = l->binary_constants;
 134   CPP_OPTION (pfile, digit_separators)           = l->digit_separators;
 135 }
 136
 137 /* Initialize library global state.  */
 138 static void
 139 init_library (void)
 140 {
 141   static int initialized = 0;
 142
 143   if (! initialized)
 144     {
 145       initialized = 1;
 146
 147       _cpp_init_lexer ();
 148
 149       /* Set up the trigraph map.  This doesn't need to do anything if
 150          we were compiled with a compiler that supports C99 designated
 151          initializers.  */
 152       init_trigraph_map ();
 153
 154 #ifdef ENABLE_NLS
 155        (void) bindtextdomain (PACKAGE, LOCALEDIR);
 156 #endif
 157     }
 158 }
 159
 160 /* Initialize a cpp_reader structure.  */
 161 cpp_reader *
 162 cpp_create_reader (enum c_lang lang, cpp_hash_table *table,
 163                    struct line_maps *line_table)
 164 {
 165   cpp_reader *pfile;
 166
 167   /* Initialize this instance of the library if it hasn't been already.  */
 168   init_library ();
 169
 170   pfile = XCNEW (cpp_reader);
 171   memset (&pfile->base_context, 0, sizeof (pfile->base_context));
 172
 173   cpp_set_lang (pfile, lang);
 174   CPP_OPTION (pfile, warn_multichar) = 1;
 175   CPP_OPTION (pfile, discard_comments) = 1;
 176   CPP_OPTION (pfile, discard_comments_in_macro_exp) = 1;
 177   CPP_OPTION (pfile, tabstop) = 8;
 178   CPP_OPTION (pfile, operator_names) = 1;
 179   CPP_OPTION (pfile, warn_trigraphs) = 2;
 180   CPP_OPTION (pfile, warn_endif_labels) = 1;
 181   CPP_OPTION (pfile, cpp_warn_deprecated) = 1;
 182   CPP_OPTION (pfile, cpp_warn_long_long) = 0;
 183   CPP_OPTION (pfile, dollars_in_ident) = 1;
 184   CPP_OPTION (pfile, warn_dollars) = 1;
 185   CPP_OPTION (pfile, warn_variadic_macros) = 1;
 186   CPP_OPTION (pfile, warn_builtin_macro_redefined) = 1;
 187   /* By default, track locations of tokens resulting from macro
 188      expansion.  The '2' means, track the locations with the highest
 189      accuracy.  Read the comments for struct
 190      cpp_options::track_macro_expansion to learn about the other
 191      values.  */
 192   CPP_OPTION (pfile, track_macro_expansion) = 2;
 193   CPP_OPTION (pfile, warn_normalize) = normalized_C;
 194   CPP_OPTION (pfile, warn_literal_suffix) = 1;
 195   CPP_OPTION (pfile, canonical_system_headers)
 196       = ENABLE_CANONICAL_SYSTEM_HEADERS;
 197   CPP_OPTION (pfile, ext_numeric_literals) = 1;
 198   CPP_OPTION (pfile, warn_date_time) = 0;
 199
 200   /* Default CPP arithmetic to something sensible for the host for the
 201      benefit of dumb users like fix-header.  */
 202   CPP_OPTION (pfile, precision) = CHAR_BIT * sizeof (long);
 203   CPP_OPTION (pfile, char_precision) = CHAR_BIT;
 204   CPP_OPTION (pfile, wchar_precision) = CHAR_BIT * sizeof (int);
 205   CPP_OPTION (pfile, int_precision) = CHAR_BIT * sizeof (int);
 206   CPP_OPTION (pfile, unsigned_char) = 0;
 207   CPP_OPTION (pfile, unsigned_wchar) = 1;
 208   CPP_OPTION (pfile, bytes_big_endian) = 1;  /* does not matter */
 209
 210   /* Default to no charset conversion.  */
 211   CPP_OPTION (pfile, narrow_charset) = _cpp_default_encoding ();
 212   CPP_OPTION (pfile, wide_charset) = 0;
 213
 214   /* Default the input character set to UTF-8.  */
 215   CPP_OPTION (pfile, input_charset) = _cpp_default_encoding ();
 216
 217   /* A fake empty "directory" used as the starting point for files
 218      looked up without a search path.  Name cannot be '/' because we
 219      don't want to prepend anything at all to filenames using it.  All
 220      other entries are correct zero-initialized.  */
 221   pfile->no_search_path.name = (char *) "";
 222
 223   /* Initialize the line map.  */
 224   pfile->line_table = line_table;
 225
 226   /* Initialize lexer state.  */
 227   pfile->state.save_comments = ! CPP_OPTION (pfile, discard_comments);
 228
 229   /* Set up static tokens.  */
 230   pfile->avoid_paste.type = CPP_PADDING;
 231   pfile->avoid_paste.val.source = NULL;
 232   pfile->eof.type = CPP_EOF;
 233   pfile->eof.flags = 0;
 234
 235   /* Create a token buffer for the lexer.  */
 236   _cpp_init_tokenrun (&pfile->base_run, 250);
 237   pfile->cur_run = &pfile->base_run;
 238   pfile->cur_token = pfile->base_run.base;
 239
 240   /* Initialize the base context.  */
 241   pfile->context = &pfile->base_context;
 242   pfile->base_context.c.macro = 0;
 243   pfile->base_context.prev = pfile->base_context.next = 0;
 244
 245   /* Aligned and unaligned storage.  */
 246   pfile->a_buff = _cpp_get_buff (pfile, 0);
 247   pfile->u_buff = _cpp_get_buff (pfile, 0);
 248
 249   /* Initialize table for push_macro/pop_macro.  */
 250   pfile->pushed_macros = 0;
 251
 252   /* Do not force token locations by default.  */
 253   pfile->forced_token_location_p = NULL;
 254
 255   /* The expression parser stack.  */
 256   _cpp_expand_op_stack (pfile);
 257
 258   /* Initialize the buffer obstack.  */
 259   _obstack_begin (&pfile->buffer_ob, 0, 0,
 260                   (void *(*) (long)) xmalloc,
 261                   (void (*) (void *)) free);
 262
 263   _cpp_init_files (pfile);
 264
 265   _cpp_init_hashtable (pfile, table);
 266
 267   return pfile;
 268 }
 269
 270 /* Set the line_table entry in PFILE.  This is called after reading a
 271    PCH file, as the old line_table will be incorrect.  */
 272 void
 273 cpp_set_line_map (cpp_reader *pfile, struct line_maps *line_table)
 274 {
 275   pfile->line_table = line_table;
 276 }
 277
 278 /* Free resources used by PFILE.  Accessing PFILE after this function
 279    returns leads to undefined behavior.  Returns the error count.  */
 280 void
 281 cpp_destroy (cpp_reader *pfile)
 282 {
 283   cpp_context *context, *contextn;
 284   struct def_pragma_macro *pmacro;
 285   tokenrun *run, *runn;
 286   int i;
 287
 288   free (pfile->op_stack);
 289
 290   while (CPP_BUFFER (pfile) != NULL)
 291     _cpp_pop_buffer (pfile);
 292
 293   free (pfile->out.base);
 294
 295   if (pfile->macro_buffer)
 296     {
 297       free (pfile->macro_buffer);
 298       pfile->macro_buffer = NULL;
 299       pfile->macro_buffer_len = 0;
 300     }
 301
 302   if (pfile->deps)
 303     deps_free (pfile->deps);
 304   obstack_free (&pfile->buffer_ob, 0);
 305
 306   _cpp_destroy_hashtable (pfile);
 307   _cpp_cleanup_files (pfile);
 308   _cpp_destroy_iconv (pfile);
 309
 310   _cpp_free_buff (pfile->a_buff);
 311   _cpp_free_buff (pfile->u_buff);
 312   _cpp_free_buff (pfile->free_buffs);
 313
 314   for (run = &pfile->base_run; run; run = runn)
 315     {
 316       runn = run->next;
 317       free (run->base);
 318       if (run != &pfile->base_run)
 319         free (run);
 320     }
 321
 322   for (context = pfile->base_context.next; context; context = contextn)
 323     {
 324       contextn = context->next;
 325       free (context);
 326     }
 327
 328   if (pfile->comments.entries)
 329     {
 330       for (i = 0; i < pfile->comments.count; i++)
 331         free (pfile->comments.entries[i].comment);
 332
 333       free (pfile->comments.entries);
 334     }
 335   if (pfile->pushed_macros)
 336     {
 337       do
 338         {
 339           pmacro = pfile->pushed_macros;
 340           pfile->pushed_macros = pmacro->next;
 341           free (pmacro->name);
 342           free (pmacro);
 343         }
 344       while (pfile->pushed_macros);
 345     }
 346
 347   free (pfile);
 348 }
 349
 350 /* This structure defines one built-in identifier.  A node will be
 351    entered in the hash table under the name NAME, with value VALUE.
 352
 353    There are two tables of these.  builtin_array holds all the
 354    "builtin" macros: these are handled by builtin_macro() in
 355    macro.c.  Builtin is somewhat of a misnomer -- the property of
 356    interest is that these macros require special code to compute their
 357    expansions.  The value is a "cpp_builtin_type" enumerator.
 358
 359    operator_array holds the C++ named operators.  These are keywords
 360    which act as aliases for punctuators.  In C++, they cannot be
 361    altered through #define, and #if recognizes them as operators.  In
 362    C, these are not entered into the hash table at all (but see
 363    <iso646.h>).  The value is a token-type enumerator.  */
 364 struct builtin_macro
 365 {
 366   const uchar *const name;
 367   const unsigned short len;
 368   const unsigned short value;
 369   const bool always_warn_if_redefined;
 370 };
 371
 372 #define B(n, t, f)    { DSC(n), t, f }
 373 static const struct builtin_macro builtin_array[] =
 374 {
 375   B("__TIMESTAMP__",     BT_TIMESTAMP,     false),
 376   B("__TIME__",          BT_TIME,          false),
 377   B("__DATE__",          BT_DATE,          false),
 378   B("__FILE__",          BT_FILE,          false),
 379   B("__BASE_FILE__",     BT_BASE_FILE,     false),
 380   B("__LINE__",          BT_SPECLINE,      true),
 381   B("__INCLUDE_LEVEL__", BT_INCLUDE_LEVEL, true),
 382   B("__COUNTER__",       BT_COUNTER,       true),
 383   /* Keep builtins not used for -traditional-cpp at the end, and
 384      update init_builtins() if any more are added.  */
 385   B("_Pragma",           BT_PRAGMA,        true),
 386   B("__STDC__",          BT_STDC,          true),
 387 };
 388 #undef B
 389
 390 struct builtin_operator
 391 {
 392   const uchar *const name;
 393   const unsigned short len;
 394   const unsigned short value;
 395 };
 396
 397 #define B(n, t)    { DSC(n), t }
 398 static const struct builtin_operator operator_array[] =
 399 {
 400   B("and",      CPP_AND_AND),
 401   B("and_eq",   CPP_AND_EQ),
 402   B("bitand",   CPP_AND),
 403   B("bitor",    CPP_OR),
 404   B("compl",    CPP_COMPL),
 405   B("not",      CPP_NOT),
 406   B("not_eq",   CPP_NOT_EQ),
 407   B("or",       CPP_OR_OR),
 408   B("or_eq",    CPP_OR_EQ),
 409   B("xor",      CPP_XOR),
 410   B("xor_eq",   CPP_XOR_EQ)
 411 };
 412 #undef B
 413
 414 /* Mark the C++ named operators in the hash table.  */
 415 static void
 416 mark_named_operators (cpp_reader *pfile, int flags)
 417 {
 418   const struct builtin_operator *b;
 419
 420   for (b = operator_array;
 421        b < (operator_array + ARRAY_SIZE (operator_array));
 422        b++)
 423     {
 424       cpp_hashnode *hp = cpp_lookup (pfile, b->name, b->len);
 425       hp->flags |= flags;
 426       hp->is_directive = 0;
 427       hp->directive_index = b->value;
 428     }
 429 }
 430
 431 /* Helper function of cpp_type2name. Return the string associated with
 432    named operator TYPE.  */
 433 const char *
 434 cpp_named_operator2name (enum cpp_ttype type)
 435 {
 436   const struct builtin_operator *b;
 437
 438   for (b = operator_array;
 439        b < (operator_array + ARRAY_SIZE (operator_array));
 440        b++)
 441     {
 442       if (type == b->value)
 443         return (const char *) b->name;
 444     }
 445
 446   return NULL;
 447 }
 448
 449 void
 450 cpp_init_special_builtins (cpp_reader *pfile)
 451 {
 452   const struct builtin_macro *b;
 453   size_t n = ARRAY_SIZE (builtin_array);
 454
 455   if (CPP_OPTION (pfile, traditional))
 456     n -= 2;
 457   else if (! CPP_OPTION (pfile, stdc_0_in_system_headers)
 458            || CPP_OPTION (pfile, std))
 459     n--;
 460
 461   for (b = builtin_array; b < builtin_array + n; b++)
 462     {
 463       cpp_hashnode *hp = cpp_lookup (pfile, b->name, b->len);
 464       hp->type = NT_MACRO;
 465       hp->flags |= NODE_BUILTIN;
 466       if (b->always_warn_if_redefined
 467           || CPP_OPTION (pfile, warn_builtin_macro_redefined))
 468         hp->flags |= NODE_WARN;
 469       hp->value.builtin = (enum cpp_builtin_type) b->value;
 470     }
 471 }
 472
 473 /* Read the builtins table above and enter them, and language-specific
 474    macros, into the hash table.  HOSTED is true if this is a hosted
 475    environment.  */
 476 void
 477 cpp_init_builtins (cpp_reader *pfile, int hosted)
 478 {
 479   cpp_init_special_builtins (pfile);
 480
 481   if (!CPP_OPTION (pfile, traditional)
 482       && (! CPP_OPTION (pfile, stdc_0_in_system_headers)
 483           || CPP_OPTION (pfile, std)))
 484     _cpp_define_builtin (pfile, "__STDC__ 1");
 485
 486   if (CPP_OPTION (pfile, cplusplus))
 487     {
 488       if (CPP_OPTION (pfile, lang) == CLK_CXX1Y
 489           || CPP_OPTION (pfile, lang) == CLK_GNUCXX1Y)
 490         _cpp_define_builtin (pfile, "__cplusplus 201300L");
 491       else if (CPP_OPTION (pfile, lang) == CLK_CXX11
 492                || CPP_OPTION (pfile, lang) == CLK_GNUCXX11)
 493         _cpp_define_builtin (pfile, "__cplusplus 201103L");
 494       else
 495         _cpp_define_builtin (pfile, "__cplusplus 199711L");
 496     }
 497   else if (CPP_OPTION (pfile, lang) == CLK_ASM)
 498     _cpp_define_builtin (pfile, "__ASSEMBLER__ 1");
 499   else if (CPP_OPTION (pfile, lang) == CLK_STDC94)
 500     _cpp_define_builtin (pfile, "__STDC_VERSION__ 199409L");
 501   else if (CPP_OPTION (pfile, lang) == CLK_STDC11
 502            || CPP_OPTION (pfile, lang) == CLK_GNUC11)
 503     _cpp_define_builtin (pfile, "__STDC_VERSION__ 201112L");
 504   else if (CPP_OPTION (pfile, c99))
 505     _cpp_define_builtin (pfile, "__STDC_VERSION__ 199901L");
 506
 507   if (CPP_OPTION (pfile, uliterals)
 508       && !CPP_OPTION (pfile, cplusplus))
 509     {
 510       _cpp_define_builtin (pfile, "__STDC_UTF_16__ 1");
 511       _cpp_define_builtin (pfile, "__STDC_UTF_32__ 1");
 512     }
 513
 514   if (hosted)
 515     _cpp_define_builtin (pfile, "__STDC_HOSTED__ 1");
 516   else
 517     _cpp_define_builtin (pfile, "__STDC_HOSTED__ 0");
 518
 519   if (CPP_OPTION (pfile, objc))
 520     _cpp_define_builtin (pfile, "__OBJC__ 1");
 521 }
 522
 523 /* Sanity-checks are dependent on command-line options, so it is
 524    called as a subroutine of cpp_read_main_file ().  */
 525 #if ENABLE_CHECKING
 526 static void sanity_checks (cpp_reader *);
 527 static void sanity_checks (cpp_reader *pfile)
 528 {
 529   cppchar_t test = 0;
 530   size_t max_precision = 2 * CHAR_BIT * sizeof (cpp_num_part);
 531
 532   /* Sanity checks for assumptions about CPP arithmetic and target
 533      type precisions made by cpplib.  */
 534   test--;
 535   if (test < 1)
 536     cpp_error (pfile, CPP_DL_ICE, "cppchar_t must be an unsigned type");
 537
 538   if (CPP_OPTION (pfile, precision) > max_precision)
 539     cpp_error (pfile, CPP_DL_ICE,
 540                "preprocessor arithmetic has maximum precision of %lu bits;"
 541                " target requires %lu bits",
 542                (unsigned long) max_precision,
 543                (unsigned long) CPP_OPTION (pfile, precision));
 544
 545   if (CPP_OPTION (pfile, precision) < CPP_OPTION (pfile, int_precision))
 546     cpp_error (pfile, CPP_DL_ICE,
 547                "CPP arithmetic must be at least as precise as a target int");
 548
 549   if (CPP_OPTION (pfile, char_precision) < 8)
 550     cpp_error (pfile, CPP_DL_ICE, "target char is less than 8 bits wide");
 551
 552   if (CPP_OPTION (pfile, wchar_precision) < CPP_OPTION (pfile, char_precision))
 553     cpp_error (pfile, CPP_DL_ICE,
 554                "target wchar_t is narrower than target char");
 555
 556   if (CPP_OPTION (pfile, int_precision) < CPP_OPTION (pfile, char_precision))
 557     cpp_error (pfile, CPP_DL_ICE,
 558                "target int is narrower than target char");
 559
 560   /* This is assumed in eval_token() and could be fixed if necessary.  */
 561   if (sizeof (cppchar_t) > sizeof (cpp_num_part))
 562     cpp_error (pfile, CPP_DL_ICE,
 563                "CPP half-integer narrower than CPP character");
 564
 565   if (CPP_OPTION (pfile, wchar_precision) > BITS_PER_CPPCHAR_T)
 566     cpp_error (pfile, CPP_DL_ICE,
 567                "CPP on this host cannot handle wide character constants over"
 568                " %lu bits, but the target requires %lu bits",
 569                (unsigned long) BITS_PER_CPPCHAR_T,
 570                (unsigned long) CPP_OPTION (pfile, wchar_precision));
 571 }
 572 #else
 573 # define sanity_checks(PFILE)
 574 #endif
 575
 576 /* This is called after options have been parsed, and partially
 577    processed.  */
 578 void
 579 cpp_post_options (cpp_reader *pfile)
 580 {
 581   int flags;
 582
 583   sanity_checks (pfile);
 584
 585   post_options (pfile);
 586
 587   /* Mark named operators before handling command line macros.  */
 588   flags = 0;
 589   if (CPP_OPTION (pfile, cplusplus) && CPP_OPTION (pfile, operator_names))
 590     flags |= NODE_OPERATOR;
 591   if (CPP_OPTION (pfile, warn_cxx_operator_names))
 592     flags |= NODE_DIAGNOSTIC | NODE_WARN_OPERATOR;
 593   if (flags != 0)
 594     mark_named_operators (pfile, flags);
 595 }
 596
 597 /* Setup for processing input from the file named FNAME, or stdin if
 598    it is the empty string.  Return the original filename
 599    on success (e.g. foo.i->foo.c), or NULL on failure.  */
 600 const char *
 601 cpp_read_main_file (cpp_reader *pfile, const char *fname)
 602 {
 603   if (CPP_OPTION (pfile, deps.style) != DEPS_NONE)
 604     {
 605       if (!pfile->deps)
 606         pfile->deps = deps_init ();
 607
 608       /* Set the default target (if there is none already).  */
 609       deps_add_default_target (pfile->deps, fname);
 610     }
 611
 612   pfile->main_file
 613     = _cpp_find_file (pfile, fname, &pfile->no_search_path, false, 0, false);
 614   if (_cpp_find_failed (pfile->main_file))
 615     return NULL;
 616
 617   _cpp_stack_file (pfile, pfile->main_file, false);
 618
 619   /* For foo.i, read the original filename foo.c now, for the benefit
 620      of the front ends.  */
 621   if (CPP_OPTION (pfile, preprocessed))
 622     {
 623       read_original_filename (pfile);
 624       fname =
 625         ORDINARY_MAP_FILE_NAME
 626         ((LINEMAPS_LAST_ORDINARY_MAP (pfile->line_table)));
 627     }
 628   return fname;
 629 }
 630
 631 /* For preprocessed files, if the first tokens are of the form # NUM.
 632    handle the directive so we know the original file name.  This will
 633    generate file_change callbacks, which the front ends must handle
 634    appropriately given their state of initialization.  */
 635 static void
 636 read_original_filename (cpp_reader *pfile)
 637 {
 638   const cpp_token *token, *token1;
 639
 640   /* Lex ahead; if the first tokens are of the form # NUM, then
 641      process the directive, otherwise back up.  */
 642   token = _cpp_lex_direct (pfile);
 643   if (token->type == CPP_HASH)
 644     {
 645       pfile->state.in_directive = 1;
 646       token1 = _cpp_lex_direct (pfile);
 647       _cpp_backup_tokens (pfile, 1);
 648       pfile->state.in_directive = 0;
 649
 650       /* If it's a #line directive, handle it.  */
 651       if (token1->type == CPP_NUMBER
 652           && _cpp_handle_directive (pfile, token->flags & PREV_WHITE))
 653         {
 654           read_original_directory (pfile);
 655           return;
 656         }
 657     }
 658
 659   /* Backup as if nothing happened.  */
 660   _cpp_backup_tokens (pfile, 1);
 661 }
 662
 663 /* For preprocessed files, if the tokens following the first filename
 664    line is of the form # <line> "/path/name//", handle the
 665    directive so we know the original current directory.  */
 666 static void
 667 read_original_directory (cpp_reader *pfile)
 668 {
 669   const cpp_token *hash, *token;
 670
 671   /* Lex ahead; if the first tokens are of the form # NUM, then
 672      process the directive, otherwise back up.  */
 673   hash = _cpp_lex_direct (pfile);
 674   if (hash->type != CPP_HASH)
 675     {
 676       _cpp_backup_tokens (pfile, 1);
 677       return;
 678     }
 679
 680   token = _cpp_lex_direct (pfile);
 681
 682   if (token->type != CPP_NUMBER)
 683     {
 684       _cpp_backup_tokens (pfile, 2);
 685       return;
 686     }
 687
 688   token = _cpp_lex_direct (pfile);
 689
 690   if (token->type != CPP_STRING
 691       || ! (token->val.str.len >= 5
 692             && IS_DIR_SEPARATOR (token->val.str.text[token->val.str.len-2])
 693             && IS_DIR_SEPARATOR (token->val.str.text[token->val.str.len-3])))
 694     {
 695       _cpp_backup_tokens (pfile, 3);
 696       return;
 697     }
 698
 699   if (pfile->cb.dir_change)
 700     {
 701       char *debugdir = (char *) alloca (token->val.str.len - 3);
 702
 703       memcpy (debugdir, (const char *) token->val.str.text + 1,
 704               token->val.str.len - 4);
 705       debugdir[token->val.str.len - 4] = '\0';
 706
 707       pfile->cb.dir_change (pfile, debugdir);
 708     }
 709 }
 710
 711 /* This is called at the end of preprocessing.  It pops the last
 712    buffer and writes dependency output.
 713
 714    Maybe it should also reset state, such that you could call
 715    cpp_start_read with a new filename to restart processing.  */
 716 void
 717 cpp_finish (cpp_reader *pfile, FILE *deps_stream)
 718 {
 719   /* Warn about unused macros before popping the final buffer.  */
 720   if (CPP_OPTION (pfile, warn_unused_macros))
 721     cpp_forall_identifiers (pfile, _cpp_warn_if_unused_macro, NULL);
 722
 723   /* lex.c leaves the final buffer on the stack.  This it so that
 724      it returns an unending stream of CPP_EOFs to the client.  If we
 725      popped the buffer, we'd dereference a NULL buffer pointer and
 726      segfault.  It's nice to allow the client to do worry-free excess
 727      cpp_get_token calls.  */
 728   while (pfile->buffer)
 729     _cpp_pop_buffer (pfile);
 730
 731   if (CPP_OPTION (pfile, deps.style) != DEPS_NONE
 732       && deps_stream)
 733     {
 734       deps_write (pfile->deps, deps_stream, 72);
 735
 736       if (CPP_OPTION (pfile, deps.phony_targets))
 737         deps_phony_targets (pfile->deps, deps_stream);
 738     }
 739
 740   /* Report on headers that could use multiple include guards.  */
 741   if (CPP_OPTION (pfile, print_include_names))
 742     _cpp_report_missing_guards (pfile);
 743 }
 744
 745 static void
 746 post_options (cpp_reader *pfile)
 747 {
 748   /* -Wtraditional is not useful in C++ mode.  */
 749   if (CPP_OPTION (pfile, cplusplus))
 750     CPP_OPTION (pfile, cpp_warn_traditional) = 0;
 751
 752   /* Permanently disable macro expansion if we are rescanning
 753      preprocessed text.  Read preprocesed source in ISO mode.  */
 754   if (CPP_OPTION (pfile, preprocessed))
 755     {
 756       if (!CPP_OPTION (pfile, directives_only))
 757         pfile->state.prevent_expansion = 1;
 758       CPP_OPTION (pfile, traditional) = 0;
 759     }
 760
 761   if (CPP_OPTION (pfile, warn_trigraphs) == 2)
 762     CPP_OPTION (pfile, warn_trigraphs) = !CPP_OPTION (pfile, trigraphs);
 763
 764   if (CPP_OPTION (pfile, traditional))
 765     {
 766       CPP_OPTION (pfile, cplusplus_comments) = 0;
 767
 768       CPP_OPTION (pfile, trigraphs) = 0;
 769       CPP_OPTION (pfile, warn_trigraphs) = 0;
 770     }
 771 }