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 #ifdef HAVE_DOS_BASED_FILE_SYSTEM
  31 #define ENABLE_CANONICAL_SYSTEM_HEADERS 1
  32 #else
  33 #define ENABLE_CANONICAL_SYSTEM_HEADERS 0
  34 #endif
  35 #endif
  36
  37 static void init_library (void);
  38 static void mark_named_operators (cpp_reader *, int);
  39 static void read_original_filename (cpp_reader *);
  40 static void read_original_directory (cpp_reader *);
  41 static void post_options (cpp_reader *);
  42
  43 /* If we have designated initializers (GCC >2.7) these tables can be
  44    initialized, constant data.  Otherwise, they have to be filled in at
  45    runtime.  */
  46 #if HAVE_DESIGNATED_INITIALIZERS
  47
  48 #define init_trigraph_map()  /* Nothing.  */
  49 #define TRIGRAPH_MAP \
  50 __extension__ const uchar _cpp_trigraph_map[UCHAR_MAX + 1] = {
  51
  52 #define END };
  53 #define s(p, v) [p] = v,
  54
  55 #else
  56
  57 #define TRIGRAPH_MAP uchar _cpp_trigraph_map[UCHAR_MAX + 1] = { 0 }; \
  58  static void init_trigraph_map (void) { \
  59  unsigned char *x = _cpp_trigraph_map;
  60
  61 #define END }
  62 #define s(p, v) x[p] = v;
  63
  64 #endif
  65
  66 TRIGRAPH_MAP
  67   s('=', '#')   s(')', ']')     s('!', '|')
  68   s('(', '[')   s('\'', '^')    s('>', '}')
  69   s('/', '\\')  s('<', '{')     s('-', '~')
  70 END
  71
  72 #undef s
  73 #undef END
  74 #undef TRIGRAPH_MAP
  75
  76 /* A set of booleans indicating what CPP features each source language
  77    requires.  */
  78 struct lang_flags
  79 {
  80   char c99;
  81   char cplusplus;
  82   char extended_numbers;
  83   char extended_identifiers;
  84   char c11_identifiers;
  85   char std;
  86   char digraphs;
  87   char uliterals;
  88   char rliterals;
  89   char user_literals;
  90   char binary_constants;
  91   char digit_separators;
  92   char trigraphs;
  93 };
  94
  95 static const struct lang_flags lang_defaults[] =
  96 { /*              c99 c++ xnum xid c11 std digr ulit rlit udlit bincst digsep trig */
  97   /* GNUC89   */  { 0,  0,  1,  0,  0,  0,  1,   0,   0,   0,    0,     0,     0 },
  98   /* GNUC99   */  { 1,  0,  1,  1,  0,  0,  1,   1,   1,   0,    0,     0,     0 },
  99   /* GNUC11   */  { 1,  0,  1,  1,  1,  0,  1,   1,   1,   0,    0,     0,     0 },
 100   /* STDC89   */  { 0,  0,  0,  0,  0,  1,  0,   0,   0,   0,    0,     0,     1 },
 101   /* STDC94   */  { 0,  0,  0,  0,  0,  1,  1,   0,   0,   0,    0,     0,     1 },
 102   /* STDC99   */  { 1,  0,  1,  1,  0,  1,  1,   0,   0,   0,    0,     0,     1 },
 103   /* STDC11   */  { 1,  0,  1,  1,  1,  1,  1,   1,   0,   0,    0,     0,     1 },
 104   /* GNUCXX   */  { 0,  1,  1,  1,  0,  0,  1,   0,   0,   0,    0,     0,     0 },
 105   /* CXX98    */  { 0,  1,  0,  1,  0,  1,  1,   0,   0,   0,    0,     0,     1 },
 106   /* GNUCXX11 */  { 1,  1,  1,  1,  1,  0,  1,   1,   1,   1,    0,     0,     0 },
 107   /* CXX11    */  { 1,  1,  1,  1,  1,  1,  1,   1,   1,   1,    0,     0,     1 },
 108   /* GNUCXX14 */  { 1,  1,  1,  1,  1,  0,  1,   1,   1,   1,    1,     1,     0 },
 109   /* CXX14    */  { 1,  1,  1,  1,  1,  1,  1,   1,   1,   1,    1,     1,     1 },
 110   /* GNUCXX1Z */  { 1,  1,  1,  1,  1,  0,  1,   1,   1,   1,    1,     1,     0 },
 111   /* CXX1Z    */  { 1,  1,  1,  1,  1,  1,  1,   1,   1,   1,    1,     1,     0 },
 112   /* ASM      */  { 0,  0,  1,  0,  0,  0,  0,   0,   0,   0,    0,     0,     0 }
 113 };
 114
 115 /* Sets internal flags correctly for a given language.  */
 116 void
 117 cpp_set_lang (cpp_reader *pfile, enum c_lang lang)
 118 {
 119   const struct lang_flags *l = &lang_defaults[(int) lang];
 120
 121   CPP_OPTION (pfile, lang) = lang;
 122
 123   CPP_OPTION (pfile, c99)                        = l->c99;
 124   CPP_OPTION (pfile, cplusplus)                  = l->cplusplus;
 125   CPP_OPTION (pfile, extended_numbers)           = l->extended_numbers;
 126   CPP_OPTION (pfile, extended_identifiers)       = l->extended_identifiers;
 127   CPP_OPTION (pfile, c11_identifiers)            = l->c11_identifiers;
 128   CPP_OPTION (pfile, std)                        = l->std;
 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   CPP_OPTION (pfile, trigraphs)                  = l->trigraphs;
 136 }
 137
 138 /* Initialize library global state.  */
 139 static void
 140 init_library (void)
 141 {
 142   static int initialized = 0;
 143
 144   if (! initialized)
 145     {
 146       initialized = 1;
 147
 148       _cpp_init_lexer ();
 149
 150       /* Set up the trigraph map.  This doesn't need to do anything if
 151          we were compiled with a compiler that supports C99 designated
 152          initializers.  */
 153       init_trigraph_map ();
 154
 155 #ifdef ENABLE_NLS
 156        (void) bindtextdomain (PACKAGE, LOCALEDIR);
 157 #endif
 158     }
 159 }
 160
 161 /* Initialize a cpp_reader structure.  */
 162 cpp_reader *
 163 cpp_create_reader (enum c_lang lang, cpp_hash_table *table,
 164                    struct line_maps *line_table)
 165 {
 166   cpp_reader *pfile;
 167
 168   /* Initialize this instance of the library if it hasn't been already.  */
 169   init_library ();
 170
 171   pfile = XCNEW (cpp_reader);
 172   memset (&pfile->base_context, 0, sizeof (pfile->base_context));
 173
 174   cpp_set_lang (pfile, lang);
 175   CPP_OPTION (pfile, warn_multichar) = 1;
 176   CPP_OPTION (pfile, discard_comments) = 1;
 177   CPP_OPTION (pfile, discard_comments_in_macro_exp) = 1;
 178   CPP_OPTION (pfile, tabstop) = 8;
 179   CPP_OPTION (pfile, operator_names) = 1;
 180   CPP_OPTION (pfile, warn_trigraphs) = 2;
 181   CPP_OPTION (pfile, warn_endif_labels) = 1;
 182   CPP_OPTION (pfile, cpp_warn_c90_c99_compat) = -1;
 183   CPP_OPTION (pfile, cpp_warn_deprecated) = 1;
 184   CPP_OPTION (pfile, cpp_warn_long_long) = 0;
 185   CPP_OPTION (pfile, dollars_in_ident) = 1;
 186   CPP_OPTION (pfile, warn_dollars) = 1;
 187   CPP_OPTION (pfile, warn_variadic_macros) = 1;
 188   CPP_OPTION (pfile, warn_builtin_macro_redefined) = 1;
 189   /* By default, track locations of tokens resulting from macro
 190      expansion.  The '2' means, track the locations with the highest
 191      accuracy.  Read the comments for struct
 192      cpp_options::track_macro_expansion to learn about the other
 193      values.  */
 194   CPP_OPTION (pfile, track_macro_expansion) = 2;
 195   CPP_OPTION (pfile, warn_normalize) = normalized_C;
 196   CPP_OPTION (pfile, warn_literal_suffix) = 1;
 197   CPP_OPTION (pfile, canonical_system_headers)
 198       = ENABLE_CANONICAL_SYSTEM_HEADERS;
 199   CPP_OPTION (pfile, ext_numeric_literals) = 1;
 200   CPP_OPTION (pfile, warn_date_time) = 0;
 201
 202   /* Default CPP arithmetic to something sensible for the host for the
 203      benefit of dumb users like fix-header.  */
 204   CPP_OPTION (pfile, precision) = CHAR_BIT * sizeof (long);
 205   CPP_OPTION (pfile, char_precision) = CHAR_BIT;
 206   CPP_OPTION (pfile, wchar_precision) = CHAR_BIT * sizeof (int);
 207   CPP_OPTION (pfile, int_precision) = CHAR_BIT * sizeof (int);
 208   CPP_OPTION (pfile, unsigned_char) = 0;
 209   CPP_OPTION (pfile, unsigned_wchar) = 1;
 210   CPP_OPTION (pfile, bytes_big_endian) = 1;  /* does not matter */
 211
 212   /* Default to no charset conversion.  */
 213   CPP_OPTION (pfile, narrow_charset) = _cpp_default_encoding ();
 214   CPP_OPTION (pfile, wide_charset) = 0;
 215
 216   /* Default the input character set to UTF-8.  */
 217   CPP_OPTION (pfile, input_charset) = _cpp_default_encoding ();
 218
 219   /* A fake empty "directory" used as the starting point for files
 220      looked up without a search path.  Name cannot be '/' because we
 221      don't want to prepend anything at all to filenames using it.  All
 222      other entries are correct zero-initialized.  */
 223   pfile->no_search_path.name = (char *) "";
 224
 225   /* Initialize the line map.  */
 226   pfile->line_table = line_table;
 227
 228   /* Initialize lexer state.  */
 229   pfile->state.save_comments = ! CPP_OPTION (pfile, discard_comments);
 230
 231   /* Set up static tokens.  */
 232   pfile->avoid_paste.type = CPP_PADDING;
 233   pfile->avoid_paste.val.source = NULL;
 234   pfile->eof.type = CPP_EOF;
 235   pfile->eof.flags = 0;
 236
 237   /* Create a token buffer for the lexer.  */
 238   _cpp_init_tokenrun (&pfile->base_run, 250);
 239   pfile->cur_run = &pfile->base_run;
 240   pfile->cur_token = pfile->base_run.base;
 241
 242   /* Initialize the base context.  */
 243   pfile->context = &pfile->base_context;
 244   pfile->base_context.c.macro = 0;
 245   pfile->base_context.prev = pfile->base_context.next = 0;
 246
 247   /* Aligned and unaligned storage.  */
 248   pfile->a_buff = _cpp_get_buff (pfile, 0);
 249   pfile->u_buff = _cpp_get_buff (pfile, 0);
 250
 251   /* Initialize table for push_macro/pop_macro.  */
 252   pfile->pushed_macros = 0;
 253
 254   /* Do not force token locations by default.  */
 255   pfile->forced_token_location_p = NULL;
 256
 257   /* The expression parser stack.  */
 258   _cpp_expand_op_stack (pfile);
 259
 260   /* Initialize the buffer obstack.  */
 261   obstack_specify_allocation (&pfile->buffer_ob, 0, 0, xmalloc, 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         hp->flags |= NODE_WARN;
 468       hp->value.builtin = (enum cpp_builtin_type) b->value;
 469     }
 470 }
 471
 472 /* Read the builtins table above and enter them, and language-specific
 473    macros, into the hash table.  HOSTED is true if this is a hosted
 474    environment.  */
 475 void
 476 cpp_init_builtins (cpp_reader *pfile, int hosted)
 477 {
 478   cpp_init_special_builtins (pfile);
 479
 480   if (!CPP_OPTION (pfile, traditional)
 481       && (! CPP_OPTION (pfile, stdc_0_in_system_headers)
 482           || CPP_OPTION (pfile, std)))
 483     _cpp_define_builtin (pfile, "__STDC__ 1");
 484
 485   if (CPP_OPTION (pfile, cplusplus))
 486     {
 487       if (CPP_OPTION (pfile, lang) == CLK_CXX1Z
 488           || CPP_OPTION (pfile, lang) == CLK_GNUCXX1Z)
 489         _cpp_define_builtin (pfile, "__cplusplus 201500L");
 490       else if (CPP_OPTION (pfile, lang) == CLK_CXX14
 491           || CPP_OPTION (pfile, lang) == CLK_GNUCXX14)
 492         _cpp_define_builtin (pfile, "__cplusplus 201402L");
 493       else if (CPP_OPTION (pfile, lang) == CLK_CXX11
 494                || CPP_OPTION (pfile, lang) == CLK_GNUCXX11)
 495         _cpp_define_builtin (pfile, "__cplusplus 201103L");
 496       else
 497         _cpp_define_builtin (pfile, "__cplusplus 199711L");
 498     }
 499   else if (CPP_OPTION (pfile, lang) == CLK_ASM)
 500     _cpp_define_builtin (pfile, "__ASSEMBLER__ 1");
 501   else if (CPP_OPTION (pfile, lang) == CLK_STDC94)
 502     _cpp_define_builtin (pfile, "__STDC_VERSION__ 199409L");
 503   else if (CPP_OPTION (pfile, lang) == CLK_STDC11
 504            || CPP_OPTION (pfile, lang) == CLK_GNUC11)
 505     _cpp_define_builtin (pfile, "__STDC_VERSION__ 201112L");
 506   else if (CPP_OPTION (pfile, c99))
 507     _cpp_define_builtin (pfile, "__STDC_VERSION__ 199901L");
 508
 509   if (CPP_OPTION (pfile, uliterals)
 510       && !(CPP_OPTION (pfile, cplusplus)
 511            && (CPP_OPTION (pfile, lang) == CLK_GNUCXX
 512             || CPP_OPTION (pfile, lang) == CLK_CXX98)))
 513     {
 514       _cpp_define_builtin (pfile, "__STDC_UTF_16__ 1");
 515       _cpp_define_builtin (pfile, "__STDC_UTF_32__ 1");
 516     }
 517
 518   if (hosted)
 519     _cpp_define_builtin (pfile, "__STDC_HOSTED__ 1");
 520   else
 521     _cpp_define_builtin (pfile, "__STDC_HOSTED__ 0");
 522
 523   if (CPP_OPTION (pfile, objc))
 524     _cpp_define_builtin (pfile, "__OBJC__ 1");
 525 }
 526
 527 /* Sanity-checks are dependent on command-line options, so it is
 528    called as a subroutine of cpp_read_main_file ().  */
 529 #if ENABLE_CHECKING
 530 static void sanity_checks (cpp_reader *);
 531 static void sanity_checks (cpp_reader *pfile)
 532 {
 533   cppchar_t test = 0;
 534   size_t max_precision = 2 * CHAR_BIT * sizeof (cpp_num_part);
 535
 536   /* Sanity checks for assumptions about CPP arithmetic and target
 537      type precisions made by cpplib.  */
 538   test--;
 539   if (test < 1)
 540     cpp_error (pfile, CPP_DL_ICE, "cppchar_t must be an unsigned type");
 541
 542   if (CPP_OPTION (pfile, precision) > max_precision)
 543     cpp_error (pfile, CPP_DL_ICE,
 544                "preprocessor arithmetic has maximum precision of %lu bits;"
 545                " target requires %lu bits",
 546                (unsigned long) max_precision,
 547                (unsigned long) CPP_OPTION (pfile, precision));
 548
 549   if (CPP_OPTION (pfile, precision) < CPP_OPTION (pfile, int_precision))
 550     cpp_error (pfile, CPP_DL_ICE,
 551                "CPP arithmetic must be at least as precise as a target int");
 552
 553   if (CPP_OPTION (pfile, char_precision) < 8)
 554     cpp_error (pfile, CPP_DL_ICE, "target char is less than 8 bits wide");
 555
 556   if (CPP_OPTION (pfile, wchar_precision) < CPP_OPTION (pfile, char_precision))
 557     cpp_error (pfile, CPP_DL_ICE,
 558                "target wchar_t is narrower than target char");
 559
 560   if (CPP_OPTION (pfile, int_precision) < CPP_OPTION (pfile, char_precision))
 561     cpp_error (pfile, CPP_DL_ICE,
 562                "target int is narrower than target char");
 563
 564   /* This is assumed in eval_token() and could be fixed if necessary.  */
 565   if (sizeof (cppchar_t) > sizeof (cpp_num_part))
 566     cpp_error (pfile, CPP_DL_ICE,
 567                "CPP half-integer narrower than CPP character");
 568
 569   if (CPP_OPTION (pfile, wchar_precision) > BITS_PER_CPPCHAR_T)
 570     cpp_error (pfile, CPP_DL_ICE,
 571                "CPP on this host cannot handle wide character constants over"
 572                " %lu bits, but the target requires %lu bits",
 573                (unsigned long) BITS_PER_CPPCHAR_T,
 574                (unsigned long) CPP_OPTION (pfile, wchar_precision));
 575 }
 576 #else
 577 # define sanity_checks(PFILE)
 578 #endif
 579
 580 /* This is called after options have been parsed, and partially
 581    processed.  */
 582 void
 583 cpp_post_options (cpp_reader *pfile)
 584 {
 585   int flags;
 586
 587   sanity_checks (pfile);
 588
 589   post_options (pfile);
 590
 591   /* Mark named operators before handling command line macros.  */
 592   flags = 0;
 593   if (CPP_OPTION (pfile, cplusplus) && CPP_OPTION (pfile, operator_names))
 594     flags |= NODE_OPERATOR;
 595   if (CPP_OPTION (pfile, warn_cxx_operator_names))
 596     flags |= NODE_DIAGNOSTIC | NODE_WARN_OPERATOR;
 597   if (flags != 0)
 598     mark_named_operators (pfile, flags);
 599 }
 600
 601 /* Setup for processing input from the file named FNAME, or stdin if
 602    it is the empty string.  Return the original filename
 603    on success (e.g. foo.i->foo.c), or NULL on failure.  */
 604 const char *
 605 cpp_read_main_file (cpp_reader *pfile, const char *fname)
 606 {
 607   if (CPP_OPTION (pfile, deps.style) != DEPS_NONE)
 608     {
 609       if (!pfile->deps)
 610         pfile->deps = deps_init ();
 611
 612       /* Set the default target (if there is none already).  */
 613       deps_add_default_target (pfile->deps, fname);
 614     }
 615
 616   pfile->main_file
 617     = _cpp_find_file (pfile, fname, &pfile->no_search_path, false, 0, false);
 618   if (_cpp_find_failed (pfile->main_file))
 619     return NULL;
 620
 621   _cpp_stack_file (pfile, pfile->main_file, false);
 622
 623   /* For foo.i, read the original filename foo.c now, for the benefit
 624      of the front ends.  */
 625   if (CPP_OPTION (pfile, preprocessed))
 626     {
 627       read_original_filename (pfile);
 628       fname =
 629         ORDINARY_MAP_FILE_NAME
 630         ((LINEMAPS_LAST_ORDINARY_MAP (pfile->line_table)));
 631     }
 632   return fname;
 633 }
 634
 635 /* For preprocessed files, if the first tokens are of the form # NUM.
 636    handle the directive so we know the original file name.  This will
 637    generate file_change callbacks, which the front ends must handle
 638    appropriately given their state of initialization.  */
 639 static void
 640 read_original_filename (cpp_reader *pfile)
 641 {
 642   const cpp_token *token, *token1;
 643
 644   /* Lex ahead; if the first tokens are of the form # NUM, then
 645      process the directive, otherwise back up.  */
 646   token = _cpp_lex_direct (pfile);
 647   if (token->type == CPP_HASH)
 648     {
 649       pfile->state.in_directive = 1;
 650       token1 = _cpp_lex_direct (pfile);
 651       _cpp_backup_tokens (pfile, 1);
 652       pfile->state.in_directive = 0;
 653
 654       /* If it's a #line directive, handle it.  */
 655       if (token1->type == CPP_NUMBER
 656           && _cpp_handle_directive (pfile, token->flags & PREV_WHITE))
 657         {
 658           read_original_directory (pfile);
 659           return;
 660         }
 661     }
 662
 663   /* Backup as if nothing happened.  */
 664   _cpp_backup_tokens (pfile, 1);
 665 }
 666
 667 /* For preprocessed files, if the tokens following the first filename
 668    line is of the form # <line> "/path/name//", handle the
 669    directive so we know the original current directory.  */
 670 static void
 671 read_original_directory (cpp_reader *pfile)
 672 {
 673   const cpp_token *hash, *token;
 674
 675   /* Lex ahead; if the first tokens are of the form # NUM, then
 676      process the directive, otherwise back up.  */
 677   hash = _cpp_lex_direct (pfile);
 678   if (hash->type != CPP_HASH)
 679     {
 680       _cpp_backup_tokens (pfile, 1);
 681       return;
 682     }
 683
 684   token = _cpp_lex_direct (pfile);
 685
 686   if (token->type != CPP_NUMBER)
 687     {
 688       _cpp_backup_tokens (pfile, 2);
 689       return;
 690     }
 691
 692   token = _cpp_lex_direct (pfile);
 693
 694   if (token->type != CPP_STRING
 695       || ! (token->val.str.len >= 5
 696             && IS_DIR_SEPARATOR (token->val.str.text[token->val.str.len-2])
 697             && IS_DIR_SEPARATOR (token->val.str.text[token->val.str.len-3])))
 698     {
 699       _cpp_backup_tokens (pfile, 3);
 700       return;
 701     }
 702
 703   if (pfile->cb.dir_change)
 704     {
 705       char *debugdir = (char *) alloca (token->val.str.len - 3);
 706
 707       memcpy (debugdir, (const char *) token->val.str.text + 1,
 708               token->val.str.len - 4);
 709       debugdir[token->val.str.len - 4] = '\0';
 710
 711       pfile->cb.dir_change (pfile, debugdir);
 712     }
 713 }
 714
 715 /* This is called at the end of preprocessing.  It pops the last
 716    buffer and writes dependency output.
 717
 718    Maybe it should also reset state, such that you could call
 719    cpp_start_read with a new filename to restart processing.  */
 720 void
 721 cpp_finish (cpp_reader *pfile, FILE *deps_stream)
 722 {
 723   /* Warn about unused macros before popping the final buffer.  */
 724   if (CPP_OPTION (pfile, warn_unused_macros))
 725     cpp_forall_identifiers (pfile, _cpp_warn_if_unused_macro, NULL);
 726
 727   /* lex.c leaves the final buffer on the stack.  This it so that
 728      it returns an unending stream of CPP_EOFs to the client.  If we
 729      popped the buffer, we'd dereference a NULL buffer pointer and
 730      segfault.  It's nice to allow the client to do worry-free excess
 731      cpp_get_token calls.  */
 732   while (pfile->buffer)
 733     _cpp_pop_buffer (pfile);
 734
 735   if (CPP_OPTION (pfile, deps.style) != DEPS_NONE
 736       && deps_stream)
 737     {
 738       deps_write (pfile->deps, deps_stream, 72);
 739
 740       if (CPP_OPTION (pfile, deps.phony_targets))
 741         deps_phony_targets (pfile->deps, deps_stream);
 742     }
 743
 744   /* Report on headers that could use multiple include guards.  */
 745   if (CPP_OPTION (pfile, print_include_names))
 746     _cpp_report_missing_guards (pfile);
 747 }
 748
 749 static void
 750 post_options (cpp_reader *pfile)
 751 {
 752   /* -Wtraditional is not useful in C++ mode.  */
 753   if (CPP_OPTION (pfile, cplusplus))
 754     CPP_OPTION (pfile, cpp_warn_traditional) = 0;
 755
 756   /* Permanently disable macro expansion if we are rescanning
 757      preprocessed text.  Read preprocesed source in ISO mode.  */
 758   if (CPP_OPTION (pfile, preprocessed))
 759     {
 760       if (!CPP_OPTION (pfile, directives_only))
 761         pfile->state.prevent_expansion = 1;
 762       CPP_OPTION (pfile, traditional) = 0;
 763     }
 764
 765   if (CPP_OPTION (pfile, warn_trigraphs) == 2)
 766     CPP_OPTION (pfile, warn_trigraphs) = !CPP_OPTION (pfile, trigraphs);
 767
 768   if (CPP_OPTION (pfile, traditional))
 769     {
 770       CPP_OPTION (pfile, trigraphs) = 0;
 771       CPP_OPTION (pfile, warn_trigraphs) = 0;
 772     }
 773 }