libcpp/init.c

   1 /* CPP Library.
   2    Copyright (C) 1986-2018 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   char utf8_char_literals;
  94   char va_opt;
  95 };
  96
  97 static const struct lang_flags lang_defaults[] =
  98 { /*              c99 c++ xnum xid c11 std digr ulit rlit udlit bincst digsep trig u8chlit vaopt */
  99   /* GNUC89   */  { 0,  0,  1,  0,  0,  0,  1,   0,   0,   0,    0,     0,     0,   0,      1 },
 100   /* GNUC99   */  { 1,  0,  1,  1,  0,  0,  1,   1,   1,   0,    0,     0,     0,   0,      1 },
 101   /* GNUC11   */  { 1,  0,  1,  1,  1,  0,  1,   1,   1,   0,    0,     0,     0,   0,      1 },
 102   /* GNUC17   */  { 1,  0,  1,  1,  1,  0,  1,   1,   1,   0,    0,     0,     0,   0,      1 },
 103   /* STDC89   */  { 0,  0,  0,  0,  0,  1,  0,   0,   0,   0,    0,     0,     1,   0,      0 },
 104   /* STDC94   */  { 0,  0,  0,  0,  0,  1,  1,   0,   0,   0,    0,     0,     1,   0,      0 },
 105   /* STDC99   */  { 1,  0,  1,  1,  0,  1,  1,   0,   0,   0,    0,     0,     1,   0,      0 },
 106   /* STDC11   */  { 1,  0,  1,  1,  1,  1,  1,   1,   0,   0,    0,     0,     1,   0,      0 },
 107   /* STDC17   */  { 1,  0,  1,  1,  1,  1,  1,   1,   0,   0,    0,     0,     1,   0,      0 },
 108   /* GNUCXX   */  { 0,  1,  1,  1,  0,  0,  1,   0,   0,   0,    0,     0,     0,   0,      1 },
 109   /* CXX98    */  { 0,  1,  0,  1,  0,  1,  1,   0,   0,   0,    0,     0,     1,   0,      0 },
 110   /* GNUCXX11 */  { 1,  1,  1,  1,  1,  0,  1,   1,   1,   1,    0,     0,     0,   0,      1 },
 111   /* CXX11    */  { 1,  1,  0,  1,  1,  1,  1,   1,   1,   1,    0,     0,     1,   0,      0 },
 112   /* GNUCXX14 */  { 1,  1,  1,  1,  1,  0,  1,   1,   1,   1,    1,     1,     0,   0,      1 },
 113   /* CXX14    */  { 1,  1,  0,  1,  1,  1,  1,   1,   1,   1,    1,     1,     1,   0,      0 },
 114   /* GNUCXX17 */  { 1,  1,  1,  1,  1,  0,  1,   1,   1,   1,    1,     1,     0,   1,      1 },
 115   /* CXX17    */  { 1,  1,  1,  1,  1,  1,  1,   1,   1,   1,    1,     1,     0,   1,      0 },
 116   /* GNUCXX2A */  { 1,  1,  1,  1,  1,  0,  1,   1,   1,   1,    1,     1,     0,   1,      1 },
 117   /* CXX2A    */  { 1,  1,  1,  1,  1,  1,  1,   1,   1,   1,    1,     1,     0,   1,      1 },
 118   /* ASM      */  { 0,  0,  1,  0,  0,  0,  0,   0,   0,   0,    0,     0,     0,   0,      0 }
 119 };
 120
 121 /* Sets internal flags correctly for a given language.  */
 122 void
 123 cpp_set_lang (cpp_reader *pfile, enum c_lang lang)
 124 {
 125   const struct lang_flags *l = &lang_defaults[(int) lang];
 126
 127   CPP_OPTION (pfile, lang) = lang;
 128
 129   CPP_OPTION (pfile, c99)                        = l->c99;
 130   CPP_OPTION (pfile, cplusplus)                  = l->cplusplus;
 131   CPP_OPTION (pfile, extended_numbers)           = l->extended_numbers;
 132   CPP_OPTION (pfile, extended_identifiers)       = l->extended_identifiers;
 133   CPP_OPTION (pfile, c11_identifiers)            = l->c11_identifiers;
 134   CPP_OPTION (pfile, std)                        = l->std;
 135   CPP_OPTION (pfile, digraphs)                   = l->digraphs;
 136   CPP_OPTION (pfile, uliterals)                  = l->uliterals;
 137   CPP_OPTION (pfile, rliterals)                  = l->rliterals;
 138   CPP_OPTION (pfile, user_literals)              = l->user_literals;
 139   CPP_OPTION (pfile, binary_constants)           = l->binary_constants;
 140   CPP_OPTION (pfile, digit_separators)           = l->digit_separators;
 141   CPP_OPTION (pfile, trigraphs)                  = l->trigraphs;
 142   CPP_OPTION (pfile, utf8_char_literals)         = l->utf8_char_literals;
 143   CPP_OPTION (pfile, va_opt)                     = l->va_opt;
 144 }
 145
 146 /* Initialize library global state.  */
 147 static void
 148 init_library (void)
 149 {
 150   static int initialized = 0;
 151
 152   if (! initialized)
 153     {
 154       initialized = 1;
 155
 156       _cpp_init_lexer ();
 157
 158       /* Set up the trigraph map.  This doesn't need to do anything if
 159          we were compiled with a compiler that supports C99 designated
 160          initializers.  */
 161       init_trigraph_map ();
 162
 163 #ifdef ENABLE_NLS
 164        (void) bindtextdomain (PACKAGE, LOCALEDIR);
 165 #endif
 166     }
 167 }
 168
 169 /* Initialize a cpp_reader structure.  */
 170 cpp_reader *
 171 cpp_create_reader (enum c_lang lang, cpp_hash_table *table,
 172                    struct line_maps *line_table)
 173 {
 174   cpp_reader *pfile;
 175
 176   /* Initialize this instance of the library if it hasn't been already.  */
 177   init_library ();
 178
 179   pfile = XCNEW (cpp_reader);
 180   memset (&pfile->base_context, 0, sizeof (pfile->base_context));
 181
 182   cpp_set_lang (pfile, lang);
 183   CPP_OPTION (pfile, warn_multichar) = 1;
 184   CPP_OPTION (pfile, discard_comments) = 1;
 185   CPP_OPTION (pfile, discard_comments_in_macro_exp) = 1;
 186   CPP_OPTION (pfile, tabstop) = 8;
 187   CPP_OPTION (pfile, operator_names) = 1;
 188   CPP_OPTION (pfile, warn_trigraphs) = 2;
 189   CPP_OPTION (pfile, warn_endif_labels) = 1;
 190   CPP_OPTION (pfile, cpp_warn_c90_c99_compat) = -1;
 191   CPP_OPTION (pfile, cpp_warn_cxx11_compat) = 0;
 192   CPP_OPTION (pfile, cpp_warn_deprecated) = 1;
 193   CPP_OPTION (pfile, cpp_warn_long_long) = 0;
 194   CPP_OPTION (pfile, dollars_in_ident) = 1;
 195   CPP_OPTION (pfile, warn_dollars) = 1;
 196   CPP_OPTION (pfile, warn_variadic_macros) = 1;
 197   CPP_OPTION (pfile, warn_builtin_macro_redefined) = 1;
 198   CPP_OPTION (pfile, cpp_warn_implicit_fallthrough) = 0;
 199   /* By default, track locations of tokens resulting from macro
 200      expansion.  The '2' means, track the locations with the highest
 201      accuracy.  Read the comments for struct
 202      cpp_options::track_macro_expansion to learn about the other
 203      values.  */
 204   CPP_OPTION (pfile, track_macro_expansion) = 2;
 205   CPP_OPTION (pfile, warn_normalize) = normalized_C;
 206   CPP_OPTION (pfile, warn_literal_suffix) = 1;
 207   CPP_OPTION (pfile, canonical_system_headers)
 208       = ENABLE_CANONICAL_SYSTEM_HEADERS;
 209   CPP_OPTION (pfile, ext_numeric_literals) = 1;
 210   CPP_OPTION (pfile, warn_date_time) = 0;
 211
 212   /* Default CPP arithmetic to something sensible for the host for the
 213      benefit of dumb users like fix-header.  */
 214   CPP_OPTION (pfile, precision) = CHAR_BIT * sizeof (long);
 215   CPP_OPTION (pfile, char_precision) = CHAR_BIT;
 216   CPP_OPTION (pfile, wchar_precision) = CHAR_BIT * sizeof (int);
 217   CPP_OPTION (pfile, int_precision) = CHAR_BIT * sizeof (int);
 218   CPP_OPTION (pfile, unsigned_char) = 0;
 219   CPP_OPTION (pfile, unsigned_wchar) = 1;
 220   CPP_OPTION (pfile, bytes_big_endian) = 1;  /* does not matter */
 221
 222   /* Default to no charset conversion.  */
 223   CPP_OPTION (pfile, narrow_charset) = _cpp_default_encoding ();
 224   CPP_OPTION (pfile, wide_charset) = 0;
 225
 226   /* Default the input character set to UTF-8.  */
 227   CPP_OPTION (pfile, input_charset) = _cpp_default_encoding ();
 228
 229   /* A fake empty "directory" used as the starting point for files
 230      looked up without a search path.  Name cannot be '/' because we
 231      don't want to prepend anything at all to filenames using it.  All
 232      other entries are correct zero-initialized.  */
 233   pfile->no_search_path.name = (char *) "";
 234
 235   /* Initialize the line map.  */
 236   pfile->line_table = line_table;
 237
 238   /* Initialize lexer state.  */
 239   pfile->state.save_comments = ! CPP_OPTION (pfile, discard_comments);
 240
 241   /* Set up static tokens.  */
 242   pfile->avoid_paste.type = CPP_PADDING;
 243   pfile->avoid_paste.val.source = NULL;
 244   pfile->eof.type = CPP_EOF;
 245   pfile->eof.flags = 0;
 246
 247   /* Create a token buffer for the lexer.  */
 248   _cpp_init_tokenrun (&pfile->base_run, 250);
 249   pfile->cur_run = &pfile->base_run;
 250   pfile->cur_token = pfile->base_run.base;
 251
 252   /* Initialize the base context.  */
 253   pfile->context = &pfile->base_context;
 254   pfile->base_context.c.macro = 0;
 255   pfile->base_context.prev = pfile->base_context.next = 0;
 256
 257   /* Aligned and unaligned storage.  */
 258   pfile->a_buff = _cpp_get_buff (pfile, 0);
 259   pfile->u_buff = _cpp_get_buff (pfile, 0);
 260
 261   /* Initialize table for push_macro/pop_macro.  */
 262   pfile->pushed_macros = 0;
 263
 264   /* Do not force token locations by default.  */
 265   pfile->forced_token_location_p = NULL;
 266
 267   /* Initialize source_date_epoch to -2 (not yet set).  */
 268   pfile->source_date_epoch = (time_t) -2;
 269
 270   /* The expression parser stack.  */
 271   _cpp_expand_op_stack (pfile);
 272
 273   /* Initialize the buffer obstack.  */
 274   obstack_specify_allocation (&pfile->buffer_ob, 0, 0, xmalloc, free);
 275
 276   _cpp_init_files (pfile);
 277
 278   _cpp_init_hashtable (pfile, table);
 279
 280   return pfile;
 281 }
 282
 283 /* Set the line_table entry in PFILE.  This is called after reading a
 284    PCH file, as the old line_table will be incorrect.  */
 285 void
 286 cpp_set_line_map (cpp_reader *pfile, struct line_maps *line_table)
 287 {
 288   pfile->line_table = line_table;
 289 }
 290
 291 /* Free resources used by PFILE.  Accessing PFILE after this function
 292    returns leads to undefined behavior.  Returns the error count.  */
 293 void
 294 cpp_destroy (cpp_reader *pfile)
 295 {
 296   cpp_context *context, *contextn;
 297   struct def_pragma_macro *pmacro;
 298   tokenrun *run, *runn;
 299   int i;
 300
 301   free (pfile->op_stack);
 302
 303   while (CPP_BUFFER (pfile) != NULL)
 304     _cpp_pop_buffer (pfile);
 305
 306   free (pfile->out.base);
 307
 308   if (pfile->macro_buffer)
 309     {
 310       free (pfile->macro_buffer);
 311       pfile->macro_buffer = NULL;
 312       pfile->macro_buffer_len = 0;
 313     }
 314
 315   if (pfile->deps)
 316     deps_free (pfile->deps);
 317   obstack_free (&pfile->buffer_ob, 0);
 318
 319   _cpp_destroy_hashtable (pfile);
 320   _cpp_cleanup_files (pfile);
 321   _cpp_destroy_iconv (pfile);
 322
 323   _cpp_free_buff (pfile->a_buff);
 324   _cpp_free_buff (pfile->u_buff);
 325   _cpp_free_buff (pfile->free_buffs);
 326
 327   for (run = &pfile->base_run; run; run = runn)
 328     {
 329       runn = run->next;
 330       free (run->base);
 331       if (run != &pfile->base_run)
 332         free (run);
 333     }
 334
 335   for (context = pfile->base_context.next; context; context = contextn)
 336     {
 337       contextn = context->next;
 338       free (context);
 339     }
 340
 341   if (pfile->comments.entries)
 342     {
 343       for (i = 0; i < pfile->comments.count; i++)
 344         free (pfile->comments.entries[i].comment);
 345
 346       free (pfile->comments.entries);
 347     }
 348   if (pfile->pushed_macros)
 349     {
 350       do
 351         {
 352           pmacro = pfile->pushed_macros;
 353           pfile->pushed_macros = pmacro->next;
 354           free (pmacro->name);
 355           free (pmacro);
 356         }
 357       while (pfile->pushed_macros);
 358     }
 359
 360   free (pfile);
 361 }
 362
 363 /* This structure defines one built-in identifier.  A node will be
 364    entered in the hash table under the name NAME, with value VALUE.
 365
 366    There are two tables of these.  builtin_array holds all the
 367    "builtin" macros: these are handled by builtin_macro() in
 368    macro.c.  Builtin is somewhat of a misnomer -- the property of
 369    interest is that these macros require special code to compute their
 370    expansions.  The value is a "cpp_builtin_type" enumerator.
 371
 372    operator_array holds the C++ named operators.  These are keywords
 373    which act as aliases for punctuators.  In C++, they cannot be
 374    altered through #define, and #if recognizes them as operators.  In
 375    C, these are not entered into the hash table at all (but see
 376    <iso646.h>).  The value is a token-type enumerator.  */
 377 struct builtin_macro
 378 {
 379   const uchar *const name;
 380   const unsigned short len;
 381   const unsigned short value;
 382   const bool always_warn_if_redefined;
 383 };
 384
 385 #define B(n, t, f)    { DSC(n), t, f }
 386 static const struct builtin_macro builtin_array[] =
 387 {
 388   B("__TIMESTAMP__",     BT_TIMESTAMP,     false),
 389   B("__TIME__",          BT_TIME,          false),
 390   B("__DATE__",          BT_DATE,          false),
 391   B("__FILE__",          BT_FILE,          false),
 392   B("__BASE_FILE__",     BT_BASE_FILE,     false),
 393   B("__LINE__",          BT_SPECLINE,      true),
 394   B("__INCLUDE_LEVEL__", BT_INCLUDE_LEVEL, true),
 395   B("__COUNTER__",       BT_COUNTER,       true),
 396   B("__has_attribute",   BT_HAS_ATTRIBUTE, true),
 397   B("__has_cpp_attribute", BT_HAS_ATTRIBUTE, true),
 398   /* Keep builtins not used for -traditional-cpp at the end, and
 399      update init_builtins() if any more are added.  */
 400   B("_Pragma",           BT_PRAGMA,        true),
 401   B("__STDC__",          BT_STDC,          true),
 402 };
 403 #undef B
 404
 405 struct builtin_operator
 406 {
 407   const uchar *const name;
 408   const unsigned short len;
 409   const unsigned short value;
 410 };
 411
 412 #define B(n, t)    { DSC(n), t }
 413 static const struct builtin_operator operator_array[] =
 414 {
 415   B("and",      CPP_AND_AND),
 416   B("and_eq",   CPP_AND_EQ),
 417   B("bitand",   CPP_AND),
 418   B("bitor",    CPP_OR),
 419   B("compl",    CPP_COMPL),
 420   B("not",      CPP_NOT),
 421   B("not_eq",   CPP_NOT_EQ),
 422   B("or",       CPP_OR_OR),
 423   B("or_eq",    CPP_OR_EQ),
 424   B("xor",      CPP_XOR),
 425   B("xor_eq",   CPP_XOR_EQ)
 426 };
 427 #undef B
 428
 429 /* Mark the C++ named operators in the hash table.  */
 430 static void
 431 mark_named_operators (cpp_reader *pfile, int flags)
 432 {
 433   const struct builtin_operator *b;
 434
 435   for (b = operator_array;
 436        b < (operator_array + ARRAY_SIZE (operator_array));
 437        b++)
 438     {
 439       cpp_hashnode *hp = cpp_lookup (pfile, b->name, b->len);
 440       hp->flags |= flags;
 441       hp->is_directive = 0;
 442       hp->directive_index = b->value;
 443     }
 444 }
 445
 446 /* Helper function of cpp_type2name. Return the string associated with
 447    named operator TYPE.  */
 448 const char *
 449 cpp_named_operator2name (enum cpp_ttype type)
 450 {
 451   const struct builtin_operator *b;
 452
 453   for (b = operator_array;
 454        b < (operator_array + ARRAY_SIZE (operator_array));
 455        b++)
 456     {
 457       if (type == b->value)
 458         return (const char *) b->name;
 459     }
 460
 461   return NULL;
 462 }
 463
 464 void
 465 cpp_init_special_builtins (cpp_reader *pfile)
 466 {
 467   const struct builtin_macro *b;
 468   size_t n = ARRAY_SIZE (builtin_array);
 469
 470   if (CPP_OPTION (pfile, traditional))
 471     n -= 2;
 472   else if (! CPP_OPTION (pfile, stdc_0_in_system_headers)
 473            || CPP_OPTION (pfile, std))
 474     n--;
 475
 476   for (b = builtin_array; b < builtin_array + n; b++)
 477     {
 478       if (b->value == BT_HAS_ATTRIBUTE
 479           && (CPP_OPTION (pfile, lang) == CLK_ASM
 480               || pfile->cb.has_attribute == NULL))
 481         continue;
 482       cpp_hashnode *hp = cpp_lookup (pfile, b->name, b->len);
 483       hp->type = NT_BUILTIN_MACRO;
 484       if (b->always_warn_if_redefined)
 485         hp->flags |= NODE_WARN;
 486       hp->value.builtin = (enum cpp_builtin_type) b->value;
 487     }
 488 }
 489
 490 /* Read the builtins table above and enter them, and language-specific
 491    macros, into the hash table.  HOSTED is true if this is a hosted
 492    environment.  */
 493 void
 494 cpp_init_builtins (cpp_reader *pfile, int hosted)
 495 {
 496   cpp_init_special_builtins (pfile);
 497
 498   if (!CPP_OPTION (pfile, traditional)
 499       && (! CPP_OPTION (pfile, stdc_0_in_system_headers)
 500           || CPP_OPTION (pfile, std)))
 501     _cpp_define_builtin (pfile, "__STDC__ 1");
 502
 503   if (CPP_OPTION (pfile, cplusplus))
 504     {
 505       if (CPP_OPTION (pfile, lang) == CLK_CXX2A
 506           || CPP_OPTION (pfile, lang) == CLK_GNUCXX2A)
 507         _cpp_define_builtin (pfile, "__cplusplus 201709L");
 508       else if (CPP_OPTION (pfile, lang) == CLK_CXX17
 509           || CPP_OPTION (pfile, lang) == CLK_GNUCXX17)
 510         _cpp_define_builtin (pfile, "__cplusplus 201703L");
 511       else if (CPP_OPTION (pfile, lang) == CLK_CXX14
 512           || CPP_OPTION (pfile, lang) == CLK_GNUCXX14)
 513         _cpp_define_builtin (pfile, "__cplusplus 201402L");
 514       else if (CPP_OPTION (pfile, lang) == CLK_CXX11
 515                || CPP_OPTION (pfile, lang) == CLK_GNUCXX11)
 516         _cpp_define_builtin (pfile, "__cplusplus 201103L");
 517       else
 518         _cpp_define_builtin (pfile, "__cplusplus 199711L");
 519     }
 520   else if (CPP_OPTION (pfile, lang) == CLK_ASM)
 521     _cpp_define_builtin (pfile, "__ASSEMBLER__ 1");
 522   else if (CPP_OPTION (pfile, lang) == CLK_STDC94)
 523     _cpp_define_builtin (pfile, "__STDC_VERSION__ 199409L");
 524   else if (CPP_OPTION (pfile, lang) == CLK_STDC17
 525            || CPP_OPTION (pfile, lang) == CLK_GNUC17)
 526     _cpp_define_builtin (pfile, "__STDC_VERSION__ 201710L");
 527   else if (CPP_OPTION (pfile, lang) == CLK_STDC11
 528            || CPP_OPTION (pfile, lang) == CLK_GNUC11)
 529     _cpp_define_builtin (pfile, "__STDC_VERSION__ 201112L");
 530   else if (CPP_OPTION (pfile, c99))
 531     _cpp_define_builtin (pfile, "__STDC_VERSION__ 199901L");
 532
 533   if (CPP_OPTION (pfile, uliterals)
 534       && !(CPP_OPTION (pfile, cplusplus)
 535            && (CPP_OPTION (pfile, lang) == CLK_GNUCXX
 536             || CPP_OPTION (pfile, lang) == CLK_CXX98)))
 537     {
 538       _cpp_define_builtin (pfile, "__STDC_UTF_16__ 1");
 539       _cpp_define_builtin (pfile, "__STDC_UTF_32__ 1");
 540     }
 541
 542   if (hosted)
 543     _cpp_define_builtin (pfile, "__STDC_HOSTED__ 1");
 544   else
 545     _cpp_define_builtin (pfile, "__STDC_HOSTED__ 0");
 546
 547   if (CPP_OPTION (pfile, objc))
 548     _cpp_define_builtin (pfile, "__OBJC__ 1");
 549 }
 550
 551 /* Sanity-checks are dependent on command-line options, so it is
 552    called as a subroutine of cpp_read_main_file.  */
 553 #if CHECKING_P
 554 static void sanity_checks (cpp_reader *);
 555 static void sanity_checks (cpp_reader *pfile)
 556 {
 557   cppchar_t test = 0;
 558   size_t max_precision = 2 * CHAR_BIT * sizeof (cpp_num_part);
 559
 560   /* Sanity checks for assumptions about CPP arithmetic and target
 561      type precisions made by cpplib.  */
 562   test--;
 563   if (test < 1)
 564     cpp_error (pfile, CPP_DL_ICE, "cppchar_t must be an unsigned type");
 565
 566   if (CPP_OPTION (pfile, precision) > max_precision)
 567     cpp_error (pfile, CPP_DL_ICE,
 568                "preprocessor arithmetic has maximum precision of %lu bits;"
 569                " target requires %lu bits",
 570                (unsigned long) max_precision,
 571                (unsigned long) CPP_OPTION (pfile, precision));
 572
 573   if (CPP_OPTION (pfile, precision) < CPP_OPTION (pfile, int_precision))
 574     cpp_error (pfile, CPP_DL_ICE,
 575                "CPP arithmetic must be at least as precise as a target int");
 576
 577   if (CPP_OPTION (pfile, char_precision) < 8)
 578     cpp_error (pfile, CPP_DL_ICE, "target char is less than 8 bits wide");
 579
 580   if (CPP_OPTION (pfile, wchar_precision) < CPP_OPTION (pfile, char_precision))
 581     cpp_error (pfile, CPP_DL_ICE,
 582                "target wchar_t is narrower than target char");
 583
 584   if (CPP_OPTION (pfile, int_precision) < CPP_OPTION (pfile, char_precision))
 585     cpp_error (pfile, CPP_DL_ICE,
 586                "target int is narrower than target char");
 587
 588   /* This is assumed in eval_token() and could be fixed if necessary.  */
 589   if (sizeof (cppchar_t) > sizeof (cpp_num_part))
 590     cpp_error (pfile, CPP_DL_ICE,
 591                "CPP half-integer narrower than CPP character");
 592
 593   if (CPP_OPTION (pfile, wchar_precision) > BITS_PER_CPPCHAR_T)
 594     cpp_error (pfile, CPP_DL_ICE,
 595                "CPP on this host cannot handle wide character constants over"
 596                " %lu bits, but the target requires %lu bits",
 597                (unsigned long) BITS_PER_CPPCHAR_T,
 598                (unsigned long) CPP_OPTION (pfile, wchar_precision));
 599 }
 600 #else
 601 # define sanity_checks(PFILE)
 602 #endif
 603
 604 /* This is called after options have been parsed, and partially
 605    processed.  */
 606 void
 607 cpp_post_options (cpp_reader *pfile)
 608 {
 609   int flags;
 610
 611   sanity_checks (pfile);
 612
 613   post_options (pfile);
 614
 615   /* Mark named operators before handling command line macros.  */
 616   flags = 0;
 617   if (CPP_OPTION (pfile, cplusplus) && CPP_OPTION (pfile, operator_names))
 618     flags |= NODE_OPERATOR;
 619   if (CPP_OPTION (pfile, warn_cxx_operator_names))
 620     flags |= NODE_DIAGNOSTIC | NODE_WARN_OPERATOR;
 621   if (flags != 0)
 622     mark_named_operators (pfile, flags);
 623 }
 624
 625 /* Setup for processing input from the file named FNAME, or stdin if
 626    it is the empty string.  Return the original filename
 627    on success (e.g. foo.i->foo.c), or NULL on failure.  */
 628 const char *
 629 cpp_read_main_file (cpp_reader *pfile, const char *fname)
 630 {
 631   const source_location loc = 0;
 632
 633   if (CPP_OPTION (pfile, deps.style) != DEPS_NONE)
 634     {
 635       if (!pfile->deps)
 636         pfile->deps = deps_init ();
 637
 638       /* Set the default target (if there is none already).  */
 639       deps_add_default_target (pfile->deps, fname);
 640     }
 641
 642   pfile->main_file
 643     = _cpp_find_file (pfile, fname, &pfile->no_search_path, false, 0, false,
 644                       loc);
 645   if (_cpp_find_failed (pfile->main_file))
 646     return NULL;
 647
 648   _cpp_stack_file (pfile, pfile->main_file, false, loc);
 649
 650   /* For foo.i, read the original filename foo.c now, for the benefit
 651      of the front ends.  */
 652   if (CPP_OPTION (pfile, preprocessed))
 653     {
 654       read_original_filename (pfile);
 655       fname =
 656         ORDINARY_MAP_FILE_NAME
 657         ((LINEMAPS_LAST_ORDINARY_MAP (pfile->line_table)));
 658     }
 659   return fname;
 660 }
 661
 662 /* For preprocessed files, if the first tokens are of the form # NUM.
 663    handle the directive so we know the original file name.  This will
 664    generate file_change callbacks, which the front ends must handle
 665    appropriately given their state of initialization.  */
 666 static void
 667 read_original_filename (cpp_reader *pfile)
 668 {
 669   const cpp_token *token, *token1;
 670
 671   /* Lex ahead; if the first tokens are of the form # NUM, then
 672      process the directive, otherwise back up.  */
 673   token = _cpp_lex_direct (pfile);
 674   if (token->type == CPP_HASH)
 675     {
 676       pfile->state.in_directive = 1;
 677       token1 = _cpp_lex_direct (pfile);
 678       _cpp_backup_tokens (pfile, 1);
 679       pfile->state.in_directive = 0;
 680
 681       /* If it's a #line directive, handle it.  */
 682       if (token1->type == CPP_NUMBER
 683           && _cpp_handle_directive (pfile, token->flags & PREV_WHITE))
 684         {
 685           read_original_directory (pfile);
 686           return;
 687         }
 688     }
 689
 690   /* Backup as if nothing happened.  */
 691   _cpp_backup_tokens (pfile, 1);
 692 }
 693
 694 /* For preprocessed files, if the tokens following the first filename
 695    line is of the form # <line> "/path/name//", handle the
 696    directive so we know the original current directory.  */
 697 static void
 698 read_original_directory (cpp_reader *pfile)
 699 {
 700   const cpp_token *hash, *token;
 701
 702   /* Lex ahead; if the first tokens are of the form # NUM, then
 703      process the directive, otherwise back up.  */
 704   hash = _cpp_lex_direct (pfile);
 705   if (hash->type != CPP_HASH)
 706     {
 707       _cpp_backup_tokens (pfile, 1);
 708       return;
 709     }
 710
 711   token = _cpp_lex_direct (pfile);
 712
 713   if (token->type != CPP_NUMBER)
 714     {
 715       _cpp_backup_tokens (pfile, 2);
 716       return;
 717     }
 718
 719   token = _cpp_lex_direct (pfile);
 720
 721   if (token->type != CPP_STRING
 722       || ! (token->val.str.len >= 5
 723             && IS_DIR_SEPARATOR (token->val.str.text[token->val.str.len-2])
 724             && IS_DIR_SEPARATOR (token->val.str.text[token->val.str.len-3])))
 725     {
 726       _cpp_backup_tokens (pfile, 3);
 727       return;
 728     }
 729
 730   if (pfile->cb.dir_change)
 731     {
 732       char *debugdir = (char *) alloca (token->val.str.len - 3);
 733
 734       memcpy (debugdir, (const char *) token->val.str.text + 1,
 735               token->val.str.len - 4);
 736       debugdir[token->val.str.len - 4] = '\0';
 737
 738       pfile->cb.dir_change (pfile, debugdir);
 739     }
 740 }
 741
 742 /* This is called at the end of preprocessing.  It pops the last
 743    buffer and writes dependency output.
 744
 745    Maybe it should also reset state, such that you could call
 746    cpp_start_read with a new filename to restart processing.  */
 747 void
 748 cpp_finish (cpp_reader *pfile, FILE *deps_stream)
 749 {
 750   /* Warn about unused macros before popping the final buffer.  */
 751   if (CPP_OPTION (pfile, warn_unused_macros))
 752     cpp_forall_identifiers (pfile, _cpp_warn_if_unused_macro, NULL);
 753
 754   /* lex.c leaves the final buffer on the stack.  This it so that
 755      it returns an unending stream of CPP_EOFs to the client.  If we
 756      popped the buffer, we'd dereference a NULL buffer pointer and
 757      segfault.  It's nice to allow the client to do worry-free excess
 758      cpp_get_token calls.  */
 759   while (pfile->buffer)
 760     _cpp_pop_buffer (pfile);
 761
 762   if (CPP_OPTION (pfile, deps.style) != DEPS_NONE
 763       && deps_stream)
 764     {
 765       deps_write (pfile->deps, deps_stream, 72);
 766
 767       if (CPP_OPTION (pfile, deps.phony_targets))
 768         deps_phony_targets (pfile->deps, deps_stream);
 769     }
 770
 771   /* Report on headers that could use multiple include guards.  */
 772   if (CPP_OPTION (pfile, print_include_names))
 773     _cpp_report_missing_guards (pfile);
 774 }
 775
 776 static void
 777 post_options (cpp_reader *pfile)
 778 {
 779   /* -Wtraditional is not useful in C++ mode.  */
 780   if (CPP_OPTION (pfile, cplusplus))
 781     CPP_OPTION (pfile, cpp_warn_traditional) = 0;
 782
 783   /* Permanently disable macro expansion if we are rescanning
 784      preprocessed text.  Read preprocesed source in ISO mode.  */
 785   if (CPP_OPTION (pfile, preprocessed))
 786     {
 787       if (!CPP_OPTION (pfile, directives_only))
 788         pfile->state.prevent_expansion = 1;
 789       CPP_OPTION (pfile, traditional) = 0;
 790     }
 791
 792   if (CPP_OPTION (pfile, warn_trigraphs) == 2)
 793     CPP_OPTION (pfile, warn_trigraphs) = !CPP_OPTION (pfile, trigraphs);
 794
 795   if (CPP_OPTION (pfile, traditional))
 796     {
 797       CPP_OPTION (pfile, trigraphs) = 0;
 798       CPP_OPTION (pfile, warn_trigraphs) = 0;
 799     }
 800 }