libcpp/init.c

   1 /* CPP Library.
   2    Copyright (C) 1986-2019 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   char scope;
  96   char dfp_constants;
  97 };
  98
  99 static const struct lang_flags lang_defaults[] =
 100 { /*              c99 c++ xnum xid c11 std digr ulit rlit udlit bincst digsep trig u8chlit vaopt scope dfp */
 101   /* GNUC89   */  { 0,  0,  1,  0,  0,  0,  1,   0,   0,   0,    0,     0,     0,   0,      1,   1,     0 },
 102   /* GNUC99   */  { 1,  0,  1,  1,  0,  0,  1,   1,   1,   0,    0,     0,     0,   0,      1,   1,     0 },
 103   /* GNUC11   */  { 1,  0,  1,  1,  1,  0,  1,   1,   1,   0,    0,     0,     0,   0,      1,   1,     0 },
 104   /* GNUC17   */  { 1,  0,  1,  1,  1,  0,  1,   1,   1,   0,    0,     0,     0,   0,      1,   1,     0 },
 105   /* GNUC2X   */  { 1,  0,  1,  1,  1,  0,  1,   1,   1,   0,    0,     0,     0,   0,      1,   1,     1 },
 106   /* STDC89   */  { 0,  0,  0,  0,  0,  1,  0,   0,   0,   0,    0,     0,     1,   0,      0,   0,     0 },
 107   /* STDC94   */  { 0,  0,  0,  0,  0,  1,  1,   0,   0,   0,    0,     0,     1,   0,      0,   0,     0 },
 108   /* STDC99   */  { 1,  0,  1,  1,  0,  1,  1,   0,   0,   0,    0,     0,     1,   0,      0,   0,     0 },
 109   /* STDC11   */  { 1,  0,  1,  1,  1,  1,  1,   1,   0,   0,    0,     0,     1,   0,      0,   0,     0 },
 110   /* STDC17   */  { 1,  0,  1,  1,  1,  1,  1,   1,   0,   0,    0,     0,     1,   0,      0,   0,     0 },
 111   /* STDC2X   */  { 1,  0,  1,  1,  1,  1,  1,   1,   0,   0,    0,     0,     1,   0,      0,   1,     1 },
 112   /* GNUCXX   */  { 0,  1,  1,  1,  0,  0,  1,   0,   0,   0,    0,     0,     0,   0,      1,   1,     0 },
 113   /* CXX98    */  { 0,  1,  0,  1,  0,  1,  1,   0,   0,   0,    0,     0,     1,   0,      0,   1,     0 },
 114   /* GNUCXX11 */  { 1,  1,  1,  1,  1,  0,  1,   1,   1,   1,    0,     0,     0,   0,      1,   1,     0 },
 115   /* CXX11    */  { 1,  1,  0,  1,  1,  1,  1,   1,   1,   1,    0,     0,     1,   0,      0,   1,     0 },
 116   /* GNUCXX14 */  { 1,  1,  1,  1,  1,  0,  1,   1,   1,   1,    1,     1,     0,   0,      1,   1,     0 },
 117   /* CXX14    */  { 1,  1,  0,  1,  1,  1,  1,   1,   1,   1,    1,     1,     1,   0,      0,   1,     0 },
 118   /* GNUCXX17 */  { 1,  1,  1,  1,  1,  0,  1,   1,   1,   1,    1,     1,     0,   1,      1,   1,     0 },
 119   /* CXX17    */  { 1,  1,  1,  1,  1,  1,  1,   1,   1,   1,    1,     1,     0,   1,      0,   1,     0 },
 120   /* GNUCXX2A */  { 1,  1,  1,  1,  1,  0,  1,   1,   1,   1,    1,     1,     0,   1,      1,   1,     0 },
 121   /* CXX2A    */  { 1,  1,  1,  1,  1,  1,  1,   1,   1,   1,    1,     1,     0,   1,      1,   1,     0 },
 122   /* ASM      */  { 0,  0,  1,  0,  0,  0,  0,   0,   0,   0,    0,     0,     0,   0,      0,   0,     0 }
 123 };
 124
 125 /* Sets internal flags correctly for a given language.  */
 126 void
 127 cpp_set_lang (cpp_reader *pfile, enum c_lang lang)
 128 {
 129   const struct lang_flags *l = &lang_defaults[(int) lang];
 130
 131   CPP_OPTION (pfile, lang) = lang;
 132
 133   CPP_OPTION (pfile, c99)                        = l->c99;
 134   CPP_OPTION (pfile, cplusplus)                  = l->cplusplus;
 135   CPP_OPTION (pfile, extended_numbers)           = l->extended_numbers;
 136   CPP_OPTION (pfile, extended_identifiers)       = l->extended_identifiers;
 137   CPP_OPTION (pfile, c11_identifiers)            = l->c11_identifiers;
 138   CPP_OPTION (pfile, std)                        = l->std;
 139   CPP_OPTION (pfile, digraphs)                   = l->digraphs;
 140   CPP_OPTION (pfile, uliterals)                  = l->uliterals;
 141   CPP_OPTION (pfile, rliterals)                  = l->rliterals;
 142   CPP_OPTION (pfile, user_literals)              = l->user_literals;
 143   CPP_OPTION (pfile, binary_constants)           = l->binary_constants;
 144   CPP_OPTION (pfile, digit_separators)           = l->digit_separators;
 145   CPP_OPTION (pfile, trigraphs)                  = l->trigraphs;
 146   CPP_OPTION (pfile, utf8_char_literals)         = l->utf8_char_literals;
 147   CPP_OPTION (pfile, va_opt)                     = l->va_opt;
 148   CPP_OPTION (pfile, scope)                      = l->scope;
 149   CPP_OPTION (pfile, dfp_constants)              = l->dfp_constants;
 150 }
 151
 152 /* Initialize library global state.  */
 153 static void
 154 init_library (void)
 155 {
 156   static int initialized = 0;
 157
 158   if (! initialized)
 159     {
 160       initialized = 1;
 161
 162       _cpp_init_lexer ();
 163
 164       /* Set up the trigraph map.  This doesn't need to do anything if
 165          we were compiled with a compiler that supports C99 designated
 166          initializers.  */
 167       init_trigraph_map ();
 168
 169 #ifdef ENABLE_NLS
 170        (void) bindtextdomain (PACKAGE, LOCALEDIR);
 171 #endif
 172     }
 173 }
 174
 175 /* Initialize a cpp_reader structure.  */
 176 cpp_reader *
 177 cpp_create_reader (enum c_lang lang, cpp_hash_table *table,
 178                    class line_maps *line_table)
 179 {
 180   cpp_reader *pfile;
 181
 182   /* Initialize this instance of the library if it hasn't been already.  */
 183   init_library ();
 184
 185   pfile = XCNEW (cpp_reader);
 186   memset (&pfile->base_context, 0, sizeof (pfile->base_context));
 187
 188   cpp_set_lang (pfile, lang);
 189   CPP_OPTION (pfile, warn_multichar) = 1;
 190   CPP_OPTION (pfile, discard_comments) = 1;
 191   CPP_OPTION (pfile, discard_comments_in_macro_exp) = 1;
 192   CPP_OPTION (pfile, max_include_depth) = 200;
 193   CPP_OPTION (pfile, tabstop) = 8;
 194   CPP_OPTION (pfile, operator_names) = 1;
 195   CPP_OPTION (pfile, warn_trigraphs) = 2;
 196   CPP_OPTION (pfile, warn_endif_labels) = 1;
 197   CPP_OPTION (pfile, cpp_warn_c90_c99_compat) = -1;
 198   CPP_OPTION (pfile, cpp_warn_c11_c2x_compat) = -1;
 199   CPP_OPTION (pfile, cpp_warn_cxx11_compat) = 0;
 200   CPP_OPTION (pfile, cpp_warn_deprecated) = 1;
 201   CPP_OPTION (pfile, cpp_warn_long_long) = 0;
 202   CPP_OPTION (pfile, dollars_in_ident) = 1;
 203   CPP_OPTION (pfile, warn_dollars) = 1;
 204   CPP_OPTION (pfile, warn_variadic_macros) = 1;
 205   CPP_OPTION (pfile, warn_builtin_macro_redefined) = 1;
 206   CPP_OPTION (pfile, cpp_warn_implicit_fallthrough) = 0;
 207   /* By default, track locations of tokens resulting from macro
 208      expansion.  The '2' means, track the locations with the highest
 209      accuracy.  Read the comments for struct
 210      cpp_options::track_macro_expansion to learn about the other
 211      values.  */
 212   CPP_OPTION (pfile, track_macro_expansion) = 2;
 213   CPP_OPTION (pfile, warn_normalize) = normalized_C;
 214   CPP_OPTION (pfile, warn_literal_suffix) = 1;
 215   CPP_OPTION (pfile, canonical_system_headers)
 216       = ENABLE_CANONICAL_SYSTEM_HEADERS;
 217   CPP_OPTION (pfile, ext_numeric_literals) = 1;
 218   CPP_OPTION (pfile, warn_date_time) = 0;
 219
 220   /* Default CPP arithmetic to something sensible for the host for the
 221      benefit of dumb users like fix-header.  */
 222   CPP_OPTION (pfile, precision) = CHAR_BIT * sizeof (long);
 223   CPP_OPTION (pfile, char_precision) = CHAR_BIT;
 224   CPP_OPTION (pfile, wchar_precision) = CHAR_BIT * sizeof (int);
 225   CPP_OPTION (pfile, int_precision) = CHAR_BIT * sizeof (int);
 226   CPP_OPTION (pfile, unsigned_char) = 0;
 227   CPP_OPTION (pfile, unsigned_wchar) = 1;
 228   CPP_OPTION (pfile, bytes_big_endian) = 1;  /* does not matter */
 229
 230   /* Default to no charset conversion.  */
 231   CPP_OPTION (pfile, narrow_charset) = _cpp_default_encoding ();
 232   CPP_OPTION (pfile, wide_charset) = 0;
 233
 234   /* Default the input character set to UTF-8.  */
 235   CPP_OPTION (pfile, input_charset) = _cpp_default_encoding ();
 236
 237   /* A fake empty "directory" used as the starting point for files
 238      looked up without a search path.  Name cannot be '/' because we
 239      don't want to prepend anything at all to filenames using it.  All
 240      other entries are correct zero-initialized.  */
 241   pfile->no_search_path.name = (char *) "";
 242
 243   /* Initialize the line map.  */
 244   pfile->line_table = line_table;
 245
 246   /* Initialize lexer state.  */
 247   pfile->state.save_comments = ! CPP_OPTION (pfile, discard_comments);
 248
 249   /* Set up static tokens.  */
 250   pfile->avoid_paste.type = CPP_PADDING;
 251   pfile->avoid_paste.val.source = NULL;
 252   pfile->eof.type = CPP_EOF;
 253   pfile->eof.flags = 0;
 254
 255   /* Create a token buffer for the lexer.  */
 256   _cpp_init_tokenrun (&pfile->base_run, 250);
 257   pfile->cur_run = &pfile->base_run;
 258   pfile->cur_token = pfile->base_run.base;
 259
 260   /* Initialize the base context.  */
 261   pfile->context = &pfile->base_context;
 262   pfile->base_context.c.macro = 0;
 263   pfile->base_context.prev = pfile->base_context.next = 0;
 264
 265   /* Aligned and unaligned storage.  */
 266   pfile->a_buff = _cpp_get_buff (pfile, 0);
 267   pfile->u_buff = _cpp_get_buff (pfile, 0);
 268
 269   /* Initialize table for push_macro/pop_macro.  */
 270   pfile->pushed_macros = 0;
 271
 272   /* Do not force token locations by default.  */
 273   pfile->forced_token_location = 0;
 274
 275   /* Initialize source_date_epoch to -2 (not yet set).  */
 276   pfile->source_date_epoch = (time_t) -2;
 277
 278   /* The expression parser stack.  */
 279   _cpp_expand_op_stack (pfile);
 280
 281   /* Initialize the buffer obstack.  */
 282   obstack_specify_allocation (&pfile->buffer_ob, 0, 0, xmalloc, free);
 283
 284   _cpp_init_files (pfile);
 285
 286   _cpp_init_hashtable (pfile, table);
 287
 288   return pfile;
 289 }
 290
 291 /* Set the line_table entry in PFILE.  This is called after reading a
 292    PCH file, as the old line_table will be incorrect.  */
 293 void
 294 cpp_set_line_map (cpp_reader *pfile, class line_maps *line_table)
 295 {
 296   pfile->line_table = line_table;
 297 }
 298
 299 /* Free resources used by PFILE.  Accessing PFILE after this function
 300    returns leads to undefined behavior.  Returns the error count.  */
 301 void
 302 cpp_destroy (cpp_reader *pfile)
 303 {
 304   cpp_context *context, *contextn;
 305   struct def_pragma_macro *pmacro;
 306   tokenrun *run, *runn;
 307   int i;
 308
 309   free (pfile->op_stack);
 310
 311   while (CPP_BUFFER (pfile) != NULL)
 312     _cpp_pop_buffer (pfile);
 313
 314   free (pfile->out.base);
 315
 316   if (pfile->macro_buffer)
 317     {
 318       free (pfile->macro_buffer);
 319       pfile->macro_buffer = NULL;
 320       pfile->macro_buffer_len = 0;
 321     }
 322
 323   if (pfile->deps)
 324     deps_free (pfile->deps);
 325   obstack_free (&pfile->buffer_ob, 0);
 326
 327   _cpp_destroy_hashtable (pfile);
 328   _cpp_cleanup_files (pfile);
 329   _cpp_destroy_iconv (pfile);
 330
 331   _cpp_free_buff (pfile->a_buff);
 332   _cpp_free_buff (pfile->u_buff);
 333   _cpp_free_buff (pfile->free_buffs);
 334
 335   for (run = &pfile->base_run; run; run = runn)
 336     {
 337       runn = run->next;
 338       free (run->base);
 339       if (run != &pfile->base_run)
 340         free (run);
 341     }
 342
 343   for (context = pfile->base_context.next; context; context = contextn)
 344     {
 345       contextn = context->next;
 346       free (context);
 347     }
 348
 349   if (pfile->comments.entries)
 350     {
 351       for (i = 0; i < pfile->comments.count; i++)
 352         free (pfile->comments.entries[i].comment);
 353
 354       free (pfile->comments.entries);
 355     }
 356   if (pfile->pushed_macros)
 357     {
 358       do
 359         {
 360           pmacro = pfile->pushed_macros;
 361           pfile->pushed_macros = pmacro->next;
 362           free (pmacro->name);
 363           free (pmacro);
 364         }
 365       while (pfile->pushed_macros);
 366     }
 367
 368   free (pfile);
 369 }
 370
 371 /* This structure defines one built-in identifier.  A node will be
 372    entered in the hash table under the name NAME, with value VALUE.
 373
 374    There are two tables of these.  builtin_array holds all the
 375    "builtin" macros: these are handled by builtin_macro() in
 376    macro.c.  Builtin is somewhat of a misnomer -- the property of
 377    interest is that these macros require special code to compute their
 378    expansions.  The value is a "cpp_builtin_type" enumerator.
 379
 380    operator_array holds the C++ named operators.  These are keywords
 381    which act as aliases for punctuators.  In C++, they cannot be
 382    altered through #define, and #if recognizes them as operators.  In
 383    C, these are not entered into the hash table at all (but see
 384    <iso646.h>).  The value is a token-type enumerator.  */
 385 struct builtin_macro
 386 {
 387   const uchar *const name;
 388   const unsigned short len;
 389   const unsigned short value;
 390   const bool always_warn_if_redefined;
 391 };
 392
 393 #define B(n, t, f)    { DSC(n), t, f }
 394 static const struct builtin_macro builtin_array[] =
 395 {
 396   B("__TIMESTAMP__",     BT_TIMESTAMP,     false),
 397   B("__TIME__",          BT_TIME,          false),
 398   B("__DATE__",          BT_DATE,          false),
 399   B("__FILE__",          BT_FILE,          false),
 400   B("__BASE_FILE__",     BT_BASE_FILE,     false),
 401   B("__LINE__",          BT_SPECLINE,      true),
 402   B("__INCLUDE_LEVEL__", BT_INCLUDE_LEVEL, true),
 403   B("__COUNTER__",       BT_COUNTER,       true),
 404   B("__has_attribute",   BT_HAS_ATTRIBUTE, true),
 405   B("__has_cpp_attribute", BT_HAS_ATTRIBUTE, true),
 406   /* Keep builtins not used for -traditional-cpp at the end, and
 407      update init_builtins() if any more are added.  */
 408   B("_Pragma",           BT_PRAGMA,        true),
 409   B("__STDC__",          BT_STDC,          true),
 410 };
 411 #undef B
 412
 413 struct builtin_operator
 414 {
 415   const uchar *const name;
 416   const unsigned short len;
 417   const unsigned short value;
 418 };
 419
 420 #define B(n, t)    { DSC(n), t }
 421 static const struct builtin_operator operator_array[] =
 422 {
 423   B("and",      CPP_AND_AND),
 424   B("and_eq",   CPP_AND_EQ),
 425   B("bitand",   CPP_AND),
 426   B("bitor",    CPP_OR),
 427   B("compl",    CPP_COMPL),
 428   B("not",      CPP_NOT),
 429   B("not_eq",   CPP_NOT_EQ),
 430   B("or",       CPP_OR_OR),
 431   B("or_eq",    CPP_OR_EQ),
 432   B("xor",      CPP_XOR),
 433   B("xor_eq",   CPP_XOR_EQ)
 434 };
 435 #undef B
 436
 437 /* Mark the C++ named operators in the hash table.  */
 438 static void
 439 mark_named_operators (cpp_reader *pfile, int flags)
 440 {
 441   const struct builtin_operator *b;
 442
 443   for (b = operator_array;
 444        b < (operator_array + ARRAY_SIZE (operator_array));
 445        b++)
 446     {
 447       cpp_hashnode *hp = cpp_lookup (pfile, b->name, b->len);
 448       hp->flags |= flags;
 449       hp->is_directive = 0;
 450       hp->directive_index = b->value;
 451     }
 452 }
 453
 454 /* Helper function of cpp_type2name. Return the string associated with
 455    named operator TYPE.  */
 456 const char *
 457 cpp_named_operator2name (enum cpp_ttype type)
 458 {
 459   const struct builtin_operator *b;
 460
 461   for (b = operator_array;
 462        b < (operator_array + ARRAY_SIZE (operator_array));
 463        b++)
 464     {
 465       if (type == b->value)
 466         return (const char *) b->name;
 467     }
 468
 469   return NULL;
 470 }
 471
 472 void
 473 cpp_init_special_builtins (cpp_reader *pfile)
 474 {
 475   const struct builtin_macro *b;
 476   size_t n = ARRAY_SIZE (builtin_array);
 477
 478   if (CPP_OPTION (pfile, traditional))
 479     n -= 2;
 480   else if (! CPP_OPTION (pfile, stdc_0_in_system_headers)
 481            || CPP_OPTION (pfile, std))
 482     n--;
 483
 484   for (b = builtin_array; b < builtin_array + n; b++)
 485     {
 486       if (b->value == BT_HAS_ATTRIBUTE
 487           && (CPP_OPTION (pfile, lang) == CLK_ASM
 488               || pfile->cb.has_attribute == NULL))
 489         continue;
 490       cpp_hashnode *hp = cpp_lookup (pfile, b->name, b->len);
 491       hp->type = NT_BUILTIN_MACRO;
 492       if (b->always_warn_if_redefined)
 493         hp->flags |= NODE_WARN;
 494       hp->value.builtin = (enum cpp_builtin_type) b->value;
 495     }
 496 }
 497
 498 /* Read the builtins table above and enter them, and language-specific
 499    macros, into the hash table.  HOSTED is true if this is a hosted
 500    environment.  */
 501 void
 502 cpp_init_builtins (cpp_reader *pfile, int hosted)
 503 {
 504   cpp_init_special_builtins (pfile);
 505
 506   if (!CPP_OPTION (pfile, traditional)
 507       && (! CPP_OPTION (pfile, stdc_0_in_system_headers)
 508           || CPP_OPTION (pfile, std)))
 509     _cpp_define_builtin (pfile, "__STDC__ 1");
 510
 511   if (CPP_OPTION (pfile, cplusplus))
 512     {
 513       if (CPP_OPTION (pfile, lang) == CLK_CXX2A
 514           || CPP_OPTION (pfile, lang) == CLK_GNUCXX2A)
 515         _cpp_define_builtin (pfile, "__cplusplus 201709L");
 516       else if (CPP_OPTION (pfile, lang) == CLK_CXX17
 517           || CPP_OPTION (pfile, lang) == CLK_GNUCXX17)
 518         _cpp_define_builtin (pfile, "__cplusplus 201703L");
 519       else if (CPP_OPTION (pfile, lang) == CLK_CXX14
 520           || CPP_OPTION (pfile, lang) == CLK_GNUCXX14)
 521         _cpp_define_builtin (pfile, "__cplusplus 201402L");
 522       else if (CPP_OPTION (pfile, lang) == CLK_CXX11
 523                || CPP_OPTION (pfile, lang) == CLK_GNUCXX11)
 524         _cpp_define_builtin (pfile, "__cplusplus 201103L");
 525       else
 526         _cpp_define_builtin (pfile, "__cplusplus 199711L");
 527     }
 528   else if (CPP_OPTION (pfile, lang) == CLK_ASM)
 529     _cpp_define_builtin (pfile, "__ASSEMBLER__ 1");
 530   else if (CPP_OPTION (pfile, lang) == CLK_STDC94)
 531     _cpp_define_builtin (pfile, "__STDC_VERSION__ 199409L");
 532   else if (CPP_OPTION (pfile, lang) == CLK_STDC2X
 533            || CPP_OPTION (pfile, lang) == CLK_GNUC2X)
 534     _cpp_define_builtin (pfile, "__STDC_VERSION__ 202000L");
 535   else if (CPP_OPTION (pfile, lang) == CLK_STDC17
 536            || CPP_OPTION (pfile, lang) == CLK_GNUC17)
 537     _cpp_define_builtin (pfile, "__STDC_VERSION__ 201710L");
 538   else if (CPP_OPTION (pfile, lang) == CLK_STDC11
 539            || CPP_OPTION (pfile, lang) == CLK_GNUC11)
 540     _cpp_define_builtin (pfile, "__STDC_VERSION__ 201112L");
 541   else if (CPP_OPTION (pfile, c99))
 542     _cpp_define_builtin (pfile, "__STDC_VERSION__ 199901L");
 543
 544   if (CPP_OPTION (pfile, uliterals)
 545       && !(CPP_OPTION (pfile, cplusplus)
 546            && (CPP_OPTION (pfile, lang) == CLK_GNUCXX
 547             || CPP_OPTION (pfile, lang) == CLK_CXX98)))
 548     {
 549       _cpp_define_builtin (pfile, "__STDC_UTF_16__ 1");
 550       _cpp_define_builtin (pfile, "__STDC_UTF_32__ 1");
 551     }
 552
 553   if (hosted)
 554     _cpp_define_builtin (pfile, "__STDC_HOSTED__ 1");
 555   else
 556     _cpp_define_builtin (pfile, "__STDC_HOSTED__ 0");
 557
 558   if (CPP_OPTION (pfile, objc))
 559     _cpp_define_builtin (pfile, "__OBJC__ 1");
 560 }
 561
 562 /* Sanity-checks are dependent on command-line options, so it is
 563    called as a subroutine of cpp_read_main_file.  */
 564 #if CHECKING_P
 565 static void sanity_checks (cpp_reader *);
 566 static void sanity_checks (cpp_reader *pfile)
 567 {
 568   cppchar_t test = 0;
 569   size_t max_precision = 2 * CHAR_BIT * sizeof (cpp_num_part);
 570
 571   /* Sanity checks for assumptions about CPP arithmetic and target
 572      type precisions made by cpplib.  */
 573   test--;
 574   if (test < 1)
 575     cpp_error (pfile, CPP_DL_ICE, "cppchar_t must be an unsigned type");
 576
 577   if (CPP_OPTION (pfile, precision) > max_precision)
 578     cpp_error (pfile, CPP_DL_ICE,
 579                "preprocessor arithmetic has maximum precision of %lu bits;"
 580                " target requires %lu bits",
 581                (unsigned long) max_precision,
 582                (unsigned long) CPP_OPTION (pfile, precision));
 583
 584   if (CPP_OPTION (pfile, precision) < CPP_OPTION (pfile, int_precision))
 585     cpp_error (pfile, CPP_DL_ICE,
 586                "CPP arithmetic must be at least as precise as a target int");
 587
 588   if (CPP_OPTION (pfile, char_precision) < 8)
 589     cpp_error (pfile, CPP_DL_ICE, "target char is less than 8 bits wide");
 590
 591   if (CPP_OPTION (pfile, wchar_precision) < CPP_OPTION (pfile, char_precision))
 592     cpp_error (pfile, CPP_DL_ICE,
 593                "target wchar_t is narrower than target char");
 594
 595   if (CPP_OPTION (pfile, int_precision) < CPP_OPTION (pfile, char_precision))
 596     cpp_error (pfile, CPP_DL_ICE,
 597                "target int is narrower than target char");
 598
 599   /* This is assumed in eval_token() and could be fixed if necessary.  */
 600   if (sizeof (cppchar_t) > sizeof (cpp_num_part))
 601     cpp_error (pfile, CPP_DL_ICE,
 602                "CPP half-integer narrower than CPP character");
 603
 604   if (CPP_OPTION (pfile, wchar_precision) > BITS_PER_CPPCHAR_T)
 605     cpp_error (pfile, CPP_DL_ICE,
 606                "CPP on this host cannot handle wide character constants over"
 607                " %lu bits, but the target requires %lu bits",
 608                (unsigned long) BITS_PER_CPPCHAR_T,
 609                (unsigned long) CPP_OPTION (pfile, wchar_precision));
 610 }
 611 #else
 612 # define sanity_checks(PFILE)
 613 #endif
 614
 615 /* This is called after options have been parsed, and partially
 616    processed.  */
 617 void
 618 cpp_post_options (cpp_reader *pfile)
 619 {
 620   int flags;
 621
 622   sanity_checks (pfile);
 623
 624   post_options (pfile);
 625
 626   /* Mark named operators before handling command line macros.  */
 627   flags = 0;
 628   if (CPP_OPTION (pfile, cplusplus) && CPP_OPTION (pfile, operator_names))
 629     flags |= NODE_OPERATOR;
 630   if (CPP_OPTION (pfile, warn_cxx_operator_names))
 631     flags |= NODE_DIAGNOSTIC | NODE_WARN_OPERATOR;
 632   if (flags != 0)
 633     mark_named_operators (pfile, flags);
 634 }
 635
 636 /* Setup for processing input from the file named FNAME, or stdin if
 637    it is the empty string.  Return the original filename
 638    on success (e.g. foo.i->foo.c), or NULL on failure.  */
 639 const char *
 640 cpp_read_main_file (cpp_reader *pfile, const char *fname)
 641 {
 642   const location_t loc = 0;
 643
 644   if (CPP_OPTION (pfile, deps.style) != DEPS_NONE)
 645     {
 646       if (!pfile->deps)
 647         pfile->deps = deps_init ();
 648
 649       /* Set the default target (if there is none already).  */
 650       deps_add_default_target (pfile->deps, fname);
 651     }
 652
 653   pfile->main_file
 654     = _cpp_find_file (pfile, fname, &pfile->no_search_path, false, 0, false,
 655                       loc);
 656   if (_cpp_find_failed (pfile->main_file))
 657     return NULL;
 658
 659   _cpp_stack_file (pfile, pfile->main_file, IT_MAIN, 0);
 660
 661   /* For foo.i, read the original filename foo.c now, for the benefit
 662      of the front ends.  */
 663   if (CPP_OPTION (pfile, preprocessed))
 664     {
 665       read_original_filename (pfile);
 666       fname =
 667         ORDINARY_MAP_FILE_NAME
 668         ((LINEMAPS_LAST_ORDINARY_MAP (pfile->line_table)));
 669     }
 670   return fname;
 671 }
 672
 673 /* For preprocessed files, if the first tokens are of the form # NUM.
 674    handle the directive so we know the original file name.  This will
 675    generate file_change callbacks, which the front ends must handle
 676    appropriately given their state of initialization.  */
 677 static void
 678 read_original_filename (cpp_reader *pfile)
 679 {
 680   const cpp_token *token, *token1;
 681
 682   /* Lex ahead; if the first tokens are of the form # NUM, then
 683      process the directive, otherwise back up.  */
 684   token = _cpp_lex_direct (pfile);
 685   if (token->type == CPP_HASH)
 686     {
 687       pfile->state.in_directive = 1;
 688       token1 = _cpp_lex_direct (pfile);
 689       _cpp_backup_tokens (pfile, 1);
 690       pfile->state.in_directive = 0;
 691
 692       /* If it's a #line directive, handle it.  */
 693       if (token1->type == CPP_NUMBER
 694           && _cpp_handle_directive (pfile, token->flags & PREV_WHITE))
 695         {
 696           read_original_directory (pfile);
 697           return;
 698         }
 699     }
 700
 701   /* Backup as if nothing happened.  */
 702   _cpp_backup_tokens (pfile, 1);
 703 }
 704
 705 /* For preprocessed files, if the tokens following the first filename
 706    line is of the form # <line> "/path/name//", handle the
 707    directive so we know the original current directory.  */
 708 static void
 709 read_original_directory (cpp_reader *pfile)
 710 {
 711   const cpp_token *hash, *token;
 712
 713   /* Lex ahead; if the first tokens are of the form # NUM, then
 714      process the directive, otherwise back up.  */
 715   hash = _cpp_lex_direct (pfile);
 716   if (hash->type != CPP_HASH)
 717     {
 718       _cpp_backup_tokens (pfile, 1);
 719       return;
 720     }
 721
 722   token = _cpp_lex_direct (pfile);
 723
 724   if (token->type != CPP_NUMBER)
 725     {
 726       _cpp_backup_tokens (pfile, 2);
 727       return;
 728     }
 729
 730   token = _cpp_lex_direct (pfile);
 731
 732   if (token->type != CPP_STRING
 733       || ! (token->val.str.len >= 5
 734             && IS_DIR_SEPARATOR (token->val.str.text[token->val.str.len-2])
 735             && IS_DIR_SEPARATOR (token->val.str.text[token->val.str.len-3])))
 736     {
 737       _cpp_backup_tokens (pfile, 3);
 738       return;
 739     }
 740
 741   if (pfile->cb.dir_change)
 742     {
 743       char *debugdir = (char *) alloca (token->val.str.len - 3);
 744
 745       memcpy (debugdir, (const char *) token->val.str.text + 1,
 746               token->val.str.len - 4);
 747       debugdir[token->val.str.len - 4] = '\0';
 748
 749       pfile->cb.dir_change (pfile, debugdir);
 750     }
 751 }
 752
 753 /* This is called at the end of preprocessing.  It pops the last
 754    buffer and writes dependency output.
 755
 756    Maybe it should also reset state, such that you could call
 757    cpp_start_read with a new filename to restart processing.  */
 758 void
 759 cpp_finish (cpp_reader *pfile, FILE *deps_stream)
 760 {
 761   /* Warn about unused macros before popping the final buffer.  */
 762   if (CPP_OPTION (pfile, warn_unused_macros))
 763     cpp_forall_identifiers (pfile, _cpp_warn_if_unused_macro, NULL);
 764
 765   /* lex.c leaves the final buffer on the stack.  This it so that
 766      it returns an unending stream of CPP_EOFs to the client.  If we
 767      popped the buffer, we'd dereference a NULL buffer pointer and
 768      segfault.  It's nice to allow the client to do worry-free excess
 769      cpp_get_token calls.  */
 770   while (pfile->buffer)
 771     _cpp_pop_buffer (pfile);
 772
 773   if (CPP_OPTION (pfile, deps.style) != DEPS_NONE && deps_stream)
 774     deps_write (pfile->deps, deps_stream,
 775                 CPP_OPTION (pfile, deps.phony_targets), 72);
 776
 777   /* Report on headers that could use multiple include guards.  */
 778   if (CPP_OPTION (pfile, print_include_names))
 779     _cpp_report_missing_guards (pfile);
 780 }
 781
 782 static void
 783 post_options (cpp_reader *pfile)
 784 {
 785   /* -Wtraditional is not useful in C++ mode.  */
 786   if (CPP_OPTION (pfile, cplusplus))
 787     CPP_OPTION (pfile, cpp_warn_traditional) = 0;
 788
 789   /* Permanently disable macro expansion if we are rescanning
 790      preprocessed text.  Read preprocesed source in ISO mode.  */
 791   if (CPP_OPTION (pfile, preprocessed))
 792     {
 793       if (!CPP_OPTION (pfile, directives_only))
 794         pfile->state.prevent_expansion = 1;
 795       CPP_OPTION (pfile, traditional) = 0;
 796     }
 797
 798   if (CPP_OPTION (pfile, warn_trigraphs) == 2)
 799     CPP_OPTION (pfile, warn_trigraphs) = !CPP_OPTION (pfile, trigraphs);
 800
 801   if (CPP_OPTION (pfile, traditional))
 802     {
 803       CPP_OPTION (pfile, trigraphs) = 0;
 804       CPP_OPTION (pfile, warn_trigraphs) = 0;
 805     }
 806 }