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,  0,  0,  0,  1,   1,   1,   0,    0,     0,     0 },
  99   /* GNUC11   */  { 1,  0,  1,  0,  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,  0,  0,  1,  1,   0,   0,   0,    0,     0,     1 },
 103   /* STDC11   */  { 1,  0,  1,  0,  1,  1,  1,   1,   0,   0,    0,     0,     1 },
 104   /* GNUCXX   */  { 0,  1,  1,  0,  0,  0,  1,   0,   0,   0,    0,     0,     0 },
 105   /* CXX98    */  { 0,  1,  0,  0,  0,  1,  1,   0,   0,   0,    0,     0,     1 },
 106   /* GNUCXX11 */  { 1,  1,  1,  0,  1,  0,  1,   1,   1,   1,    0,     0,     0 },
 107   /* CXX11    */  { 1,  1,  1,  0,  1,  1,  1,   1,   1,   1,    0,     0,     1 },
 108   /* GNUCXX14 */  { 1,  1,  1,  0,  1,  0,  1,   1,   1,   1,    1,     1,     0 },
 109   /* CXX14    */  { 1,  1,  1,  0,  1,  1,  1,   1,   1,   1,    1,     1,     1 },
 110   /* GNUCXX1Z */  { 1,  1,  1,  0,  1,  0,  1,   1,   1,   1,    1,     1,     0 },
 111   /* CXX1Z    */  { 1,  1,  1,  0,  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   /* xid should be 1 for GNUC99, STDC99, GNUCXX, CXX98, GNUCXX11, CXX11,
 114      GNUCXX14, and CXX14 when no longer experimental (when all uses of
 115      identifiers in the compiler have been audited for correct handling
 116      of extended identifiers).  */
 117 };
 118
 119 /* Sets internal flags correctly for a given language.  */
 120 void
 121 cpp_set_lang (cpp_reader *pfile, enum c_lang lang)
 122 {
 123   const struct lang_flags *l = &lang_defaults[(int) lang];
 124
 125   CPP_OPTION (pfile, lang) = lang;
 126
 127   CPP_OPTION (pfile, c99)                        = l->c99;
 128   CPP_OPTION (pfile, cplusplus)                  = l->cplusplus;
 129   CPP_OPTION (pfile, extended_numbers)           = l->extended_numbers;
 130   CPP_OPTION (pfile, extended_identifiers)       = l->extended_identifiers;
 131   CPP_OPTION (pfile, c11_identifiers)            = l->c11_identifiers;
 132   CPP_OPTION (pfile, std)                        = l->std;
 133   CPP_OPTION (pfile, digraphs)                   = l->digraphs;
 134   CPP_OPTION (pfile, uliterals)                  = l->uliterals;
 135   CPP_OPTION (pfile, rliterals)                  = l->rliterals;
 136   CPP_OPTION (pfile, user_literals)              = l->user_literals;
 137   CPP_OPTION (pfile, binary_constants)           = l->binary_constants;
 138   CPP_OPTION (pfile, digit_separators)           = l->digit_separators;
 139   CPP_OPTION (pfile, trigraphs)                  = l->trigraphs;
 140 }
 141
 142 /* Initialize library global state.  */
 143 static void
 144 init_library (void)
 145 {
 146   static int initialized = 0;
 147
 148   if (! initialized)
 149     {
 150       initialized = 1;
 151
 152       _cpp_init_lexer ();
 153
 154       /* Set up the trigraph map.  This doesn't need to do anything if
 155          we were compiled with a compiler that supports C99 designated
 156          initializers.  */
 157       init_trigraph_map ();
 158
 159 #ifdef ENABLE_NLS
 160        (void) bindtextdomain (PACKAGE, LOCALEDIR);
 161 #endif
 162     }
 163 }
 164
 165 /* Initialize a cpp_reader structure.  */
 166 cpp_reader *
 167 cpp_create_reader (enum c_lang lang, cpp_hash_table *table,
 168                    struct line_maps *line_table)
 169 {
 170   cpp_reader *pfile;
 171
 172   /* Initialize this instance of the library if it hasn't been already.  */
 173   init_library ();
 174
 175   pfile = XCNEW (cpp_reader);
 176   memset (&pfile->base_context, 0, sizeof (pfile->base_context));
 177
 178   cpp_set_lang (pfile, lang);
 179   CPP_OPTION (pfile, warn_multichar) = 1;
 180   CPP_OPTION (pfile, discard_comments) = 1;
 181   CPP_OPTION (pfile, discard_comments_in_macro_exp) = 1;
 182   CPP_OPTION (pfile, tabstop) = 8;
 183   CPP_OPTION (pfile, operator_names) = 1;
 184   CPP_OPTION (pfile, warn_trigraphs) = 2;
 185   CPP_OPTION (pfile, warn_endif_labels) = 1;
 186   CPP_OPTION (pfile, cpp_warn_c90_c99_compat) = -1;
 187   CPP_OPTION (pfile, cpp_warn_deprecated) = 1;
 188   CPP_OPTION (pfile, cpp_warn_long_long) = 0;
 189   CPP_OPTION (pfile, dollars_in_ident) = 1;
 190   CPP_OPTION (pfile, warn_dollars) = 1;
 191   CPP_OPTION (pfile, warn_variadic_macros) = 1;
 192   CPP_OPTION (pfile, warn_builtin_macro_redefined) = 1;
 193   /* By default, track locations of tokens resulting from macro
 194      expansion.  The '2' means, track the locations with the highest
 195      accuracy.  Read the comments for struct
 196      cpp_options::track_macro_expansion to learn about the other
 197      values.  */
 198   CPP_OPTION (pfile, track_macro_expansion) = 2;
 199   CPP_OPTION (pfile, warn_normalize) = normalized_C;
 200   CPP_OPTION (pfile, warn_literal_suffix) = 1;
 201   CPP_OPTION (pfile, canonical_system_headers)
 202       = ENABLE_CANONICAL_SYSTEM_HEADERS;
 203   CPP_OPTION (pfile, ext_numeric_literals) = 1;
 204   CPP_OPTION (pfile, warn_date_time) = 0;
 205
 206   /* Default CPP arithmetic to something sensible for the host for the
 207      benefit of dumb users like fix-header.  */
 208   CPP_OPTION (pfile, precision) = CHAR_BIT * sizeof (long);
 209   CPP_OPTION (pfile, char_precision) = CHAR_BIT;
 210   CPP_OPTION (pfile, wchar_precision) = CHAR_BIT * sizeof (int);
 211   CPP_OPTION (pfile, int_precision) = CHAR_BIT * sizeof (int);
 212   CPP_OPTION (pfile, unsigned_char) = 0;
 213   CPP_OPTION (pfile, unsigned_wchar) = 1;
 214   CPP_OPTION (pfile, bytes_big_endian) = 1;  /* does not matter */
 215
 216   /* Default to no charset conversion.  */
 217   CPP_OPTION (pfile, narrow_charset) = _cpp_default_encoding ();
 218   CPP_OPTION (pfile, wide_charset) = 0;
 219
 220   /* Default the input character set to UTF-8.  */
 221   CPP_OPTION (pfile, input_charset) = _cpp_default_encoding ();
 222
 223   /* A fake empty "directory" used as the starting point for files
 224      looked up without a search path.  Name cannot be '/' because we
 225      don't want to prepend anything at all to filenames using it.  All
 226      other entries are correct zero-initialized.  */
 227   pfile->no_search_path.name = (char *) "";
 228
 229   /* Initialize the line map.  */
 230   pfile->line_table = line_table;
 231
 232   /* Initialize lexer state.  */
 233   pfile->state.save_comments = ! CPP_OPTION (pfile, discard_comments);
 234
 235   /* Set up static tokens.  */
 236   pfile->avoid_paste.type = CPP_PADDING;
 237   pfile->avoid_paste.val.source = NULL;
 238   pfile->eof.type = CPP_EOF;
 239   pfile->eof.flags = 0;
 240
 241   /* Create a token buffer for the lexer.  */
 242   _cpp_init_tokenrun (&pfile->base_run, 250);
 243   pfile->cur_run = &pfile->base_run;
 244   pfile->cur_token = pfile->base_run.base;
 245
 246   /* Initialize the base context.  */
 247   pfile->context = &pfile->base_context;
 248   pfile->base_context.c.macro = 0;
 249   pfile->base_context.prev = pfile->base_context.next = 0;
 250
 251   /* Aligned and unaligned storage.  */
 252   pfile->a_buff = _cpp_get_buff (pfile, 0);
 253   pfile->u_buff = _cpp_get_buff (pfile, 0);
 254
 255   /* Initialize table for push_macro/pop_macro.  */
 256   pfile->pushed_macros = 0;
 257
 258   /* Do not force token locations by default.  */
 259   pfile->forced_token_location_p = NULL;
 260
 261   /* The expression parser stack.  */
 262   _cpp_expand_op_stack (pfile);
 263
 264   /* Initialize the buffer obstack.  */
 265   obstack_specify_allocation (&pfile->buffer_ob, 0, 0, xmalloc, free);
 266
 267   _cpp_init_files (pfile);
 268
 269   _cpp_init_hashtable (pfile, table);
 270
 271   return pfile;
 272 }
 273
 274 /* Set the line_table entry in PFILE.  This is called after reading a
 275    PCH file, as the old line_table will be incorrect.  */
 276 void
 277 cpp_set_line_map (cpp_reader *pfile, struct line_maps *line_table)
 278 {
 279   pfile->line_table = line_table;
 280 }
 281
 282 /* Free resources used by PFILE.  Accessing PFILE after this function
 283    returns leads to undefined behavior.  Returns the error count.  */
 284 void
 285 cpp_destroy (cpp_reader *pfile)
 286 {
 287   cpp_context *context, *contextn;
 288   struct def_pragma_macro *pmacro;
 289   tokenrun *run, *runn;
 290   int i;
 291
 292   free (pfile->op_stack);
 293
 294   while (CPP_BUFFER (pfile) != NULL)
 295     _cpp_pop_buffer (pfile);
 296
 297   free (pfile->out.base);
 298
 299   if (pfile->macro_buffer)
 300     {
 301       free (pfile->macro_buffer);
 302       pfile->macro_buffer = NULL;
 303       pfile->macro_buffer_len = 0;
 304     }
 305
 306   if (pfile->deps)
 307     deps_free (pfile->deps);
 308   obstack_free (&pfile->buffer_ob, 0);
 309
 310   _cpp_destroy_hashtable (pfile);
 311   _cpp_cleanup_files (pfile);
 312   _cpp_destroy_iconv (pfile);
 313
 314   _cpp_free_buff (pfile->a_buff);
 315   _cpp_free_buff (pfile->u_buff);
 316   _cpp_free_buff (pfile->free_buffs);
 317
 318   for (run = &pfile->base_run; run; run = runn)
 319     {
 320       runn = run->next;
 321       free (run->base);
 322       if (run != &pfile->base_run)
 323         free (run);
 324     }
 325
 326   for (context = pfile->base_context.next; context; context = contextn)
 327     {
 328       contextn = context->next;
 329       free (context);
 330     }
 331
 332   if (pfile->comments.entries)
 333     {
 334       for (i = 0; i < pfile->comments.count; i++)
 335         free (pfile->comments.entries[i].comment);
 336
 337       free (pfile->comments.entries);
 338     }
 339   if (pfile->pushed_macros)
 340     {
 341       do
 342         {
 343           pmacro = pfile->pushed_macros;
 344           pfile->pushed_macros = pmacro->next;
 345           free (pmacro->name);
 346           free (pmacro);
 347         }
 348       while (pfile->pushed_macros);
 349     }
 350
 351   free (pfile);
 352 }
 353
 354 /* This structure defines one built-in identifier.  A node will be
 355    entered in the hash table under the name NAME, with value VALUE.
 356
 357    There are two tables of these.  builtin_array holds all the
 358    "builtin" macros: these are handled by builtin_macro() in
 359    macro.c.  Builtin is somewhat of a misnomer -- the property of
 360    interest is that these macros require special code to compute their
 361    expansions.  The value is a "cpp_builtin_type" enumerator.
 362
 363    operator_array holds the C++ named operators.  These are keywords
 364    which act as aliases for punctuators.  In C++, they cannot be
 365    altered through #define, and #if recognizes them as operators.  In
 366    C, these are not entered into the hash table at all (but see
 367    <iso646.h>).  The value is a token-type enumerator.  */
 368 struct builtin_macro
 369 {
 370   const uchar *const name;
 371   const unsigned short len;
 372   const unsigned short value;
 373   const bool always_warn_if_redefined;
 374 };
 375
 376 #define B(n, t, f)    { DSC(n), t, f }
 377 static const struct builtin_macro builtin_array[] =
 378 {
 379   B("__TIMESTAMP__",     BT_TIMESTAMP,     false),
 380   B("__TIME__",          BT_TIME,          false),
 381   B("__DATE__",          BT_DATE,          false),
 382   B("__FILE__",          BT_FILE,          false),
 383   B("__BASE_FILE__",     BT_BASE_FILE,     false),
 384   B("__LINE__",          BT_SPECLINE,      true),
 385   B("__INCLUDE_LEVEL__", BT_INCLUDE_LEVEL, true),
 386   B("__COUNTER__",       BT_COUNTER,       true),
 387   /* Keep builtins not used for -traditional-cpp at the end, and
 388      update init_builtins() if any more are added.  */
 389   B("_Pragma",           BT_PRAGMA,        true),
 390   B("__STDC__",          BT_STDC,          true),
 391 };
 392 #undef B
 393
 394 struct builtin_operator
 395 {
 396   const uchar *const name;
 397   const unsigned short len;
 398   const unsigned short value;
 399 };
 400
 401 #define B(n, t)    { DSC(n), t }
 402 static const struct builtin_operator operator_array[] =
 403 {
 404   B("and",      CPP_AND_AND),
 405   B("and_eq",   CPP_AND_EQ),
 406   B("bitand",   CPP_AND),
 407   B("bitor",    CPP_OR),
 408   B("compl",    CPP_COMPL),
 409   B("not",      CPP_NOT),
 410   B("not_eq",   CPP_NOT_EQ),
 411   B("or",       CPP_OR_OR),
 412   B("or_eq",    CPP_OR_EQ),
 413   B("xor",      CPP_XOR),
 414   B("xor_eq",   CPP_XOR_EQ)
 415 };
 416 #undef B
 417
 418 /* Mark the C++ named operators in the hash table.  */
 419 static void
 420 mark_named_operators (cpp_reader *pfile, int flags)
 421 {
 422   const struct builtin_operator *b;
 423
 424   for (b = operator_array;
 425        b < (operator_array + ARRAY_SIZE (operator_array));
 426        b++)
 427     {
 428       cpp_hashnode *hp = cpp_lookup (pfile, b->name, b->len);
 429       hp->flags |= flags;
 430       hp->is_directive = 0;
 431       hp->directive_index = b->value;
 432     }
 433 }
 434
 435 /* Helper function of cpp_type2name. Return the string associated with
 436    named operator TYPE.  */
 437 const char *
 438 cpp_named_operator2name (enum cpp_ttype type)
 439 {
 440   const struct builtin_operator *b;
 441
 442   for (b = operator_array;
 443        b < (operator_array + ARRAY_SIZE (operator_array));
 444        b++)
 445     {
 446       if (type == b->value)
 447         return (const char *) b->name;
 448     }
 449
 450   return NULL;
 451 }
 452
 453 void
 454 cpp_init_special_builtins (cpp_reader *pfile)
 455 {
 456   const struct builtin_macro *b;
 457   size_t n = ARRAY_SIZE (builtin_array);
 458
 459   if (CPP_OPTION (pfile, traditional))
 460     n -= 2;
 461   else if (! CPP_OPTION (pfile, stdc_0_in_system_headers)
 462            || CPP_OPTION (pfile, std))
 463     n--;
 464
 465   for (b = builtin_array; b < builtin_array + n; b++)
 466     {
 467       cpp_hashnode *hp = cpp_lookup (pfile, b->name, b->len);
 468       hp->type = NT_MACRO;
 469       hp->flags |= NODE_BUILTIN;
 470       if (b->always_warn_if_redefined)
 471         hp->flags |= NODE_WARN;
 472       hp->value.builtin = (enum cpp_builtin_type) b->value;
 473     }
 474 }
 475
 476 /* Read the builtins table above and enter them, and language-specific
 477    macros, into the hash table.  HOSTED is true if this is a hosted
 478    environment.  */
 479 void
 480 cpp_init_builtins (cpp_reader *pfile, int hosted)
 481 {
 482   cpp_init_special_builtins (pfile);
 483
 484   if (!CPP_OPTION (pfile, traditional)
 485       && (! CPP_OPTION (pfile, stdc_0_in_system_headers)
 486           || CPP_OPTION (pfile, std)))
 487     _cpp_define_builtin (pfile, "__STDC__ 1");
 488
 489   if (CPP_OPTION (pfile, cplusplus))
 490     {
 491       if (CPP_OPTION (pfile, lang) == CLK_CXX1Z
 492           || CPP_OPTION (pfile, lang) == CLK_GNUCXX1Z)
 493         _cpp_define_builtin (pfile, "__cplusplus 201500L");
 494       else if (CPP_OPTION (pfile, lang) == CLK_CXX14
 495           || CPP_OPTION (pfile, lang) == CLK_GNUCXX14)
 496         _cpp_define_builtin (pfile, "__cplusplus 201402L");
 497       else if (CPP_OPTION (pfile, lang) == CLK_CXX11
 498                || CPP_OPTION (pfile, lang) == CLK_GNUCXX11)
 499         _cpp_define_builtin (pfile, "__cplusplus 201103L");
 500       else
 501         _cpp_define_builtin (pfile, "__cplusplus 199711L");
 502     }
 503   else if (CPP_OPTION (pfile, lang) == CLK_ASM)
 504     _cpp_define_builtin (pfile, "__ASSEMBLER__ 1");
 505   else if (CPP_OPTION (pfile, lang) == CLK_STDC94)
 506     _cpp_define_builtin (pfile, "__STDC_VERSION__ 199409L");
 507   else if (CPP_OPTION (pfile, lang) == CLK_STDC11
 508            || CPP_OPTION (pfile, lang) == CLK_GNUC11)
 509     _cpp_define_builtin (pfile, "__STDC_VERSION__ 201112L");
 510   else if (CPP_OPTION (pfile, c99))
 511     _cpp_define_builtin (pfile, "__STDC_VERSION__ 199901L");
 512
 513   if (CPP_OPTION (pfile, uliterals)
 514       && !(CPP_OPTION (pfile, cplusplus)
 515            && (CPP_OPTION (pfile, lang) == CLK_GNUCXX
 516             || CPP_OPTION (pfile, lang) == CLK_CXX98)))
 517     {
 518       _cpp_define_builtin (pfile, "__STDC_UTF_16__ 1");
 519       _cpp_define_builtin (pfile, "__STDC_UTF_32__ 1");
 520     }
 521
 522   if (hosted)
 523     _cpp_define_builtin (pfile, "__STDC_HOSTED__ 1");
 524   else
 525     _cpp_define_builtin (pfile, "__STDC_HOSTED__ 0");
 526
 527   if (CPP_OPTION (pfile, objc))
 528     _cpp_define_builtin (pfile, "__OBJC__ 1");
 529 }
 530
 531 /* Sanity-checks are dependent on command-line options, so it is
 532    called as a subroutine of cpp_read_main_file ().  */
 533 #if ENABLE_CHECKING
 534 static void sanity_checks (cpp_reader *);
 535 static void sanity_checks (cpp_reader *pfile)
 536 {
 537   cppchar_t test = 0;
 538   size_t max_precision = 2 * CHAR_BIT * sizeof (cpp_num_part);
 539
 540   /* Sanity checks for assumptions about CPP arithmetic and target
 541      type precisions made by cpplib.  */
 542   test--;
 543   if (test < 1)
 544     cpp_error (pfile, CPP_DL_ICE, "cppchar_t must be an unsigned type");
 545
 546   if (CPP_OPTION (pfile, precision) > max_precision)
 547     cpp_error (pfile, CPP_DL_ICE,
 548                "preprocessor arithmetic has maximum precision of %lu bits;"
 549                " target requires %lu bits",
 550                (unsigned long) max_precision,
 551                (unsigned long) CPP_OPTION (pfile, precision));
 552
 553   if (CPP_OPTION (pfile, precision) < CPP_OPTION (pfile, int_precision))
 554     cpp_error (pfile, CPP_DL_ICE,
 555                "CPP arithmetic must be at least as precise as a target int");
 556
 557   if (CPP_OPTION (pfile, char_precision) < 8)
 558     cpp_error (pfile, CPP_DL_ICE, "target char is less than 8 bits wide");
 559
 560   if (CPP_OPTION (pfile, wchar_precision) < CPP_OPTION (pfile, char_precision))
 561     cpp_error (pfile, CPP_DL_ICE,
 562                "target wchar_t is narrower than target char");
 563
 564   if (CPP_OPTION (pfile, int_precision) < CPP_OPTION (pfile, char_precision))
 565     cpp_error (pfile, CPP_DL_ICE,
 566                "target int is narrower than target char");
 567
 568   /* This is assumed in eval_token() and could be fixed if necessary.  */
 569   if (sizeof (cppchar_t) > sizeof (cpp_num_part))
 570     cpp_error (pfile, CPP_DL_ICE,
 571                "CPP half-integer narrower than CPP character");
 572
 573   if (CPP_OPTION (pfile, wchar_precision) > BITS_PER_CPPCHAR_T)
 574     cpp_error (pfile, CPP_DL_ICE,
 575                "CPP on this host cannot handle wide character constants over"
 576                " %lu bits, but the target requires %lu bits",
 577                (unsigned long) BITS_PER_CPPCHAR_T,
 578                (unsigned long) CPP_OPTION (pfile, wchar_precision));
 579 }
 580 #else
 581 # define sanity_checks(PFILE)
 582 #endif
 583
 584 /* This is called after options have been parsed, and partially
 585    processed.  */
 586 void
 587 cpp_post_options (cpp_reader *pfile)
 588 {
 589   int flags;
 590
 591   sanity_checks (pfile);
 592
 593   post_options (pfile);
 594
 595   /* Mark named operators before handling command line macros.  */
 596   flags = 0;
 597   if (CPP_OPTION (pfile, cplusplus) && CPP_OPTION (pfile, operator_names))
 598     flags |= NODE_OPERATOR;
 599   if (CPP_OPTION (pfile, warn_cxx_operator_names))
 600     flags |= NODE_DIAGNOSTIC | NODE_WARN_OPERATOR;
 601   if (flags != 0)
 602     mark_named_operators (pfile, flags);
 603 }
 604
 605 /* Setup for processing input from the file named FNAME, or stdin if
 606    it is the empty string.  Return the original filename
 607    on success (e.g. foo.i->foo.c), or NULL on failure.  */
 608 const char *
 609 cpp_read_main_file (cpp_reader *pfile, const char *fname)
 610 {
 611   if (CPP_OPTION (pfile, deps.style) != DEPS_NONE)
 612     {
 613       if (!pfile->deps)
 614         pfile->deps = deps_init ();
 615
 616       /* Set the default target (if there is none already).  */
 617       deps_add_default_target (pfile->deps, fname);
 618     }
 619
 620   pfile->main_file
 621     = _cpp_find_file (pfile, fname, &pfile->no_search_path, false, 0, false);
 622   if (_cpp_find_failed (pfile->main_file))
 623     return NULL;
 624
 625   _cpp_stack_file (pfile, pfile->main_file, false);
 626
 627   /* For foo.i, read the original filename foo.c now, for the benefit
 628      of the front ends.  */
 629   if (CPP_OPTION (pfile, preprocessed))
 630     {
 631       read_original_filename (pfile);
 632       fname =
 633         ORDINARY_MAP_FILE_NAME
 634         ((LINEMAPS_LAST_ORDINARY_MAP (pfile->line_table)));
 635     }
 636   return fname;
 637 }
 638
 639 /* For preprocessed files, if the first tokens are of the form # NUM.
 640    handle the directive so we know the original file name.  This will
 641    generate file_change callbacks, which the front ends must handle
 642    appropriately given their state of initialization.  */
 643 static void
 644 read_original_filename (cpp_reader *pfile)
 645 {
 646   const cpp_token *token, *token1;
 647
 648   /* Lex ahead; if the first tokens are of the form # NUM, then
 649      process the directive, otherwise back up.  */
 650   token = _cpp_lex_direct (pfile);
 651   if (token->type == CPP_HASH)
 652     {
 653       pfile->state.in_directive = 1;
 654       token1 = _cpp_lex_direct (pfile);
 655       _cpp_backup_tokens (pfile, 1);
 656       pfile->state.in_directive = 0;
 657
 658       /* If it's a #line directive, handle it.  */
 659       if (token1->type == CPP_NUMBER
 660           && _cpp_handle_directive (pfile, token->flags & PREV_WHITE))
 661         {
 662           read_original_directory (pfile);
 663           return;
 664         }
 665     }
 666
 667   /* Backup as if nothing happened.  */
 668   _cpp_backup_tokens (pfile, 1);
 669 }
 670
 671 /* For preprocessed files, if the tokens following the first filename
 672    line is of the form # <line> "/path/name//", handle the
 673    directive so we know the original current directory.  */
 674 static void
 675 read_original_directory (cpp_reader *pfile)
 676 {
 677   const cpp_token *hash, *token;
 678
 679   /* Lex ahead; if the first tokens are of the form # NUM, then
 680      process the directive, otherwise back up.  */
 681   hash = _cpp_lex_direct (pfile);
 682   if (hash->type != CPP_HASH)
 683     {
 684       _cpp_backup_tokens (pfile, 1);
 685       return;
 686     }
 687
 688   token = _cpp_lex_direct (pfile);
 689
 690   if (token->type != CPP_NUMBER)
 691     {
 692       _cpp_backup_tokens (pfile, 2);
 693       return;
 694     }
 695
 696   token = _cpp_lex_direct (pfile);
 697
 698   if (token->type != CPP_STRING
 699       || ! (token->val.str.len >= 5
 700             && IS_DIR_SEPARATOR (token->val.str.text[token->val.str.len-2])
 701             && IS_DIR_SEPARATOR (token->val.str.text[token->val.str.len-3])))
 702     {
 703       _cpp_backup_tokens (pfile, 3);
 704       return;
 705     }
 706
 707   if (pfile->cb.dir_change)
 708     {
 709       char *debugdir = (char *) alloca (token->val.str.len - 3);
 710
 711       memcpy (debugdir, (const char *) token->val.str.text + 1,
 712               token->val.str.len - 4);
 713       debugdir[token->val.str.len - 4] = '\0';
 714
 715       pfile->cb.dir_change (pfile, debugdir);
 716     }
 717 }
 718
 719 /* This is called at the end of preprocessing.  It pops the last
 720    buffer and writes dependency output.
 721
 722    Maybe it should also reset state, such that you could call
 723    cpp_start_read with a new filename to restart processing.  */
 724 void
 725 cpp_finish (cpp_reader *pfile, FILE *deps_stream)
 726 {
 727   /* Warn about unused macros before popping the final buffer.  */
 728   if (CPP_OPTION (pfile, warn_unused_macros))
 729     cpp_forall_identifiers (pfile, _cpp_warn_if_unused_macro, NULL);
 730
 731   /* lex.c leaves the final buffer on the stack.  This it so that
 732      it returns an unending stream of CPP_EOFs to the client.  If we
 733      popped the buffer, we'd dereference a NULL buffer pointer and
 734      segfault.  It's nice to allow the client to do worry-free excess
 735      cpp_get_token calls.  */
 736   while (pfile->buffer)
 737     _cpp_pop_buffer (pfile);
 738
 739   if (CPP_OPTION (pfile, deps.style) != DEPS_NONE
 740       && deps_stream)
 741     {
 742       deps_write (pfile->deps, deps_stream, 72);
 743
 744       if (CPP_OPTION (pfile, deps.phony_targets))
 745         deps_phony_targets (pfile->deps, deps_stream);
 746     }
 747
 748   /* Report on headers that could use multiple include guards.  */
 749   if (CPP_OPTION (pfile, print_include_names))
 750     _cpp_report_missing_guards (pfile);
 751 }
 752
 753 static void
 754 post_options (cpp_reader *pfile)
 755 {
 756   /* -Wtraditional is not useful in C++ mode.  */
 757   if (CPP_OPTION (pfile, cplusplus))
 758     CPP_OPTION (pfile, cpp_warn_traditional) = 0;
 759
 760   /* Permanently disable macro expansion if we are rescanning
 761      preprocessed text.  Read preprocesed source in ISO mode.  */
 762   if (CPP_OPTION (pfile, preprocessed))
 763     {
 764       if (!CPP_OPTION (pfile, directives_only))
 765         pfile->state.prevent_expansion = 1;
 766       CPP_OPTION (pfile, traditional) = 0;
 767     }
 768
 769   if (CPP_OPTION (pfile, warn_trigraphs) == 2)
 770     CPP_OPTION (pfile, warn_trigraphs) = !CPP_OPTION (pfile, trigraphs);
 771
 772   if (CPP_OPTION (pfile, traditional))
 773     {
 774       CPP_OPTION (pfile, trigraphs) = 0;
 775       CPP_OPTION (pfile, warn_trigraphs) = 0;
 776     }
 777 }