libcpp/init.c

   1 /* CPP Library.
   2    Copyright (C) 1986-2020 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,   1,      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,   1,      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   B("__has_builtin",     BT_HAS_BUILTIN,   true),
 407   /* Keep builtins not used for -traditional-cpp at the end, and
 408      update init_builtins() if any more are added.  */
 409   B("_Pragma",           BT_PRAGMA,        true),
 410   B("__STDC__",          BT_STDC,          true),
 411 };
 412 #undef B
 413
 414 struct builtin_operator
 415 {
 416   const uchar *const name;
 417   const unsigned short len;
 418   const unsigned short value;
 419 };
 420
 421 #define B(n, t)    { DSC(n), t }
 422 static const struct builtin_operator operator_array[] =
 423 {
 424   B("and",      CPP_AND_AND),
 425   B("and_eq",   CPP_AND_EQ),
 426   B("bitand",   CPP_AND),
 427   B("bitor",    CPP_OR),
 428   B("compl",    CPP_COMPL),
 429   B("not",      CPP_NOT),
 430   B("not_eq",   CPP_NOT_EQ),
 431   B("or",       CPP_OR_OR),
 432   B("or_eq",    CPP_OR_EQ),
 433   B("xor",      CPP_XOR),
 434   B("xor_eq",   CPP_XOR_EQ)
 435 };
 436 #undef B
 437
 438 /* Mark the C++ named operators in the hash table.  */
 439 static void
 440 mark_named_operators (cpp_reader *pfile, int flags)
 441 {
 442   const struct builtin_operator *b;
 443
 444   for (b = operator_array;
 445        b < (operator_array + ARRAY_SIZE (operator_array));
 446        b++)
 447     {
 448       cpp_hashnode *hp = cpp_lookup (pfile, b->name, b->len);
 449       hp->flags |= flags;
 450       hp->is_directive = 0;
 451       hp->directive_index = b->value;
 452     }
 453 }
 454
 455 /* Helper function of cpp_type2name. Return the string associated with
 456    named operator TYPE.  */
 457 const char *
 458 cpp_named_operator2name (enum cpp_ttype type)
 459 {
 460   const struct builtin_operator *b;
 461
 462   for (b = operator_array;
 463        b < (operator_array + ARRAY_SIZE (operator_array));
 464        b++)
 465     {
 466       if (type == b->value)
 467         return (const char *) b->name;
 468     }
 469
 470   return NULL;
 471 }
 472
 473 void
 474 cpp_init_special_builtins (cpp_reader *pfile)
 475 {
 476   const struct builtin_macro *b;
 477   size_t n = ARRAY_SIZE (builtin_array);
 478
 479   if (CPP_OPTION (pfile, traditional))
 480     n -= 2;
 481   else if (! CPP_OPTION (pfile, stdc_0_in_system_headers)
 482            || CPP_OPTION (pfile, std))
 483     n--;
 484
 485   for (b = builtin_array; b < builtin_array + n; b++)
 486     {
 487       if ((b->value == BT_HAS_ATTRIBUTE
 488            || b->value == BT_HAS_BUILTIN)
 489           && (CPP_OPTION (pfile, lang) == CLK_ASM
 490               || pfile->cb.has_attribute == NULL))
 491         continue;
 492       cpp_hashnode *hp = cpp_lookup (pfile, b->name, b->len);
 493       hp->type = NT_BUILTIN_MACRO;
 494       if (b->always_warn_if_redefined)
 495         hp->flags |= NODE_WARN;
 496       hp->value.builtin = (enum cpp_builtin_type) b->value;
 497     }
 498 }
 499
 500 /* Restore macro C to builtin macro definition.  */
 501
 502 void
 503 _cpp_restore_special_builtin (cpp_reader *pfile, struct def_pragma_macro *c)
 504 {
 505   size_t len = strlen (c->name);
 506
 507   for (const struct builtin_macro *b = builtin_array;
 508        b < builtin_array + ARRAY_SIZE (builtin_array); b++)
 509     if (b->len == len && memcmp (c->name, b->name, len + 1) == 0)
 510       {
 511         cpp_hashnode *hp = cpp_lookup (pfile, b->name, b->len);
 512         hp->type = NT_BUILTIN_MACRO;
 513         if (b->always_warn_if_redefined)
 514           hp->flags |= NODE_WARN;
 515         hp->value.builtin = (enum cpp_builtin_type) b->value;
 516       }
 517 }
 518
 519 /* Read the builtins table above and enter them, and language-specific
 520    macros, into the hash table.  HOSTED is true if this is a hosted
 521    environment.  */
 522 void
 523 cpp_init_builtins (cpp_reader *pfile, int hosted)
 524 {
 525   cpp_init_special_builtins (pfile);
 526
 527   if (!CPP_OPTION (pfile, traditional)
 528       && (! CPP_OPTION (pfile, stdc_0_in_system_headers)
 529           || CPP_OPTION (pfile, std)))
 530     _cpp_define_builtin (pfile, "__STDC__ 1");
 531
 532   if (CPP_OPTION (pfile, cplusplus))
 533     {
 534       if (CPP_OPTION (pfile, lang) == CLK_CXX2A
 535           || CPP_OPTION (pfile, lang) == CLK_GNUCXX2A)
 536         _cpp_define_builtin (pfile, "__cplusplus 201709L");
 537       else if (CPP_OPTION (pfile, lang) == CLK_CXX17
 538           || CPP_OPTION (pfile, lang) == CLK_GNUCXX17)
 539         _cpp_define_builtin (pfile, "__cplusplus 201703L");
 540       else if (CPP_OPTION (pfile, lang) == CLK_CXX14
 541           || CPP_OPTION (pfile, lang) == CLK_GNUCXX14)
 542         _cpp_define_builtin (pfile, "__cplusplus 201402L");
 543       else if (CPP_OPTION (pfile, lang) == CLK_CXX11
 544                || CPP_OPTION (pfile, lang) == CLK_GNUCXX11)
 545         _cpp_define_builtin (pfile, "__cplusplus 201103L");
 546       else
 547         _cpp_define_builtin (pfile, "__cplusplus 199711L");
 548     }
 549   else if (CPP_OPTION (pfile, lang) == CLK_ASM)
 550     _cpp_define_builtin (pfile, "__ASSEMBLER__ 1");
 551   else if (CPP_OPTION (pfile, lang) == CLK_STDC94)
 552     _cpp_define_builtin (pfile, "__STDC_VERSION__ 199409L");
 553   else if (CPP_OPTION (pfile, lang) == CLK_STDC2X
 554            || CPP_OPTION (pfile, lang) == CLK_GNUC2X)
 555     _cpp_define_builtin (pfile, "__STDC_VERSION__ 202000L");
 556   else if (CPP_OPTION (pfile, lang) == CLK_STDC17
 557            || CPP_OPTION (pfile, lang) == CLK_GNUC17)
 558     _cpp_define_builtin (pfile, "__STDC_VERSION__ 201710L");
 559   else if (CPP_OPTION (pfile, lang) == CLK_STDC11
 560            || CPP_OPTION (pfile, lang) == CLK_GNUC11)
 561     _cpp_define_builtin (pfile, "__STDC_VERSION__ 201112L");
 562   else if (CPP_OPTION (pfile, c99))
 563     _cpp_define_builtin (pfile, "__STDC_VERSION__ 199901L");
 564
 565   if (CPP_OPTION (pfile, uliterals)
 566       && !(CPP_OPTION (pfile, cplusplus)
 567            && (CPP_OPTION (pfile, lang) == CLK_GNUCXX
 568             || CPP_OPTION (pfile, lang) == CLK_CXX98)))
 569     {
 570       _cpp_define_builtin (pfile, "__STDC_UTF_16__ 1");
 571       _cpp_define_builtin (pfile, "__STDC_UTF_32__ 1");
 572     }
 573
 574   if (hosted)
 575     _cpp_define_builtin (pfile, "__STDC_HOSTED__ 1");
 576   else
 577     _cpp_define_builtin (pfile, "__STDC_HOSTED__ 0");
 578
 579   if (CPP_OPTION (pfile, objc))
 580     _cpp_define_builtin (pfile, "__OBJC__ 1");
 581
 582   /* These two behave as macros for #ifdef, but are evaluated
 583      specially inside #if.  */
 584   _cpp_define_builtin (pfile, "__has_include __has_include");
 585   _cpp_define_builtin (pfile, "__has_include_next __has_include_next");
 586   pfile->spec_nodes.n__has_include
 587     = cpp_lookup (pfile, DSC("__has_include"));
 588   pfile->spec_nodes.n__has_include->flags |= NODE_DIAGNOSTIC;
 589   pfile->spec_nodes.n__has_include_next
 590     = cpp_lookup (pfile, DSC("__has_include_next"));
 591   pfile->spec_nodes.n__has_include_next->flags |= NODE_DIAGNOSTIC;
 592 }
 593
 594 /* Sanity-checks are dependent on command-line options, so it is
 595    called as a subroutine of cpp_read_main_file.  */
 596 #if CHECKING_P
 597 static void sanity_checks (cpp_reader *);
 598 static void sanity_checks (cpp_reader *pfile)
 599 {
 600   cppchar_t test = 0;
 601   size_t max_precision = 2 * CHAR_BIT * sizeof (cpp_num_part);
 602
 603   /* Sanity checks for assumptions about CPP arithmetic and target
 604      type precisions made by cpplib.  */
 605   test--;
 606   if (test < 1)
 607     cpp_error (pfile, CPP_DL_ICE, "cppchar_t must be an unsigned type");
 608
 609   if (CPP_OPTION (pfile, precision) > max_precision)
 610     cpp_error (pfile, CPP_DL_ICE,
 611                "preprocessor arithmetic has maximum precision of %lu bits;"
 612                " target requires %lu bits",
 613                (unsigned long) max_precision,
 614                (unsigned long) CPP_OPTION (pfile, precision));
 615
 616   if (CPP_OPTION (pfile, precision) < CPP_OPTION (pfile, int_precision))
 617     cpp_error (pfile, CPP_DL_ICE,
 618                "CPP arithmetic must be at least as precise as a target int");
 619
 620   if (CPP_OPTION (pfile, char_precision) < 8)
 621     cpp_error (pfile, CPP_DL_ICE, "target char is less than 8 bits wide");
 622
 623   if (CPP_OPTION (pfile, wchar_precision) < CPP_OPTION (pfile, char_precision))
 624     cpp_error (pfile, CPP_DL_ICE,
 625                "target wchar_t is narrower than target char");
 626
 627   if (CPP_OPTION (pfile, int_precision) < CPP_OPTION (pfile, char_precision))
 628     cpp_error (pfile, CPP_DL_ICE,
 629                "target int is narrower than target char");
 630
 631   /* This is assumed in eval_token() and could be fixed if necessary.  */
 632   if (sizeof (cppchar_t) > sizeof (cpp_num_part))
 633     cpp_error (pfile, CPP_DL_ICE,
 634                "CPP half-integer narrower than CPP character");
 635
 636   if (CPP_OPTION (pfile, wchar_precision) > BITS_PER_CPPCHAR_T)
 637     cpp_error (pfile, CPP_DL_ICE,
 638                "CPP on this host cannot handle wide character constants over"
 639                " %lu bits, but the target requires %lu bits",
 640                (unsigned long) BITS_PER_CPPCHAR_T,
 641                (unsigned long) CPP_OPTION (pfile, wchar_precision));
 642 }
 643 #else
 644 # define sanity_checks(PFILE)
 645 #endif
 646
 647 /* This is called after options have been parsed, and partially
 648    processed.  */
 649 void
 650 cpp_post_options (cpp_reader *pfile)
 651 {
 652   int flags;
 653
 654   sanity_checks (pfile);
 655
 656   post_options (pfile);
 657
 658   /* Mark named operators before handling command line macros.  */
 659   flags = 0;
 660   if (CPP_OPTION (pfile, cplusplus) && CPP_OPTION (pfile, operator_names))
 661     flags |= NODE_OPERATOR;
 662   if (CPP_OPTION (pfile, warn_cxx_operator_names))
 663     flags |= NODE_DIAGNOSTIC | NODE_WARN_OPERATOR;
 664   if (flags != 0)
 665     mark_named_operators (pfile, flags);
 666 }
 667
 668 /* Setup for processing input from the file named FNAME, or stdin if
 669    it is the empty string.  Return the original filename
 670    on success (e.g. foo.i->foo.c), or NULL on failure.  */
 671 const char *
 672 cpp_read_main_file (cpp_reader *pfile, const char *fname)
 673 {
 674   const location_t loc = 0;
 675
 676   if (CPP_OPTION (pfile, deps.style) != DEPS_NONE)
 677     {
 678       if (!pfile->deps)
 679         pfile->deps = deps_init ();
 680
 681       /* Set the default target (if there is none already).  */
 682       deps_add_default_target (pfile->deps, fname);
 683     }
 684
 685   pfile->main_file
 686     = _cpp_find_file (pfile, fname, &pfile->no_search_path, /*angle=*/0,
 687                       /*fake=*/false, /*preinclude=*/false, /*hasinclude=*/false,
 688                       loc);
 689   if (_cpp_find_failed (pfile->main_file))
 690     return NULL;
 691
 692   _cpp_stack_file (pfile, pfile->main_file, IT_MAIN, 0);
 693
 694   /* For foo.i, read the original filename foo.c now, for the benefit
 695      of the front ends.  */
 696   if (CPP_OPTION (pfile, preprocessed))
 697     {
 698       read_original_filename (pfile);
 699       fname =
 700         ORDINARY_MAP_FILE_NAME
 701         ((LINEMAPS_LAST_ORDINARY_MAP (pfile->line_table)));
 702     }
 703   return fname;
 704 }
 705
 706 /* For preprocessed files, if the first tokens are of the form # NUM.
 707    handle the directive so we know the original file name.  This will
 708    generate file_change callbacks, which the front ends must handle
 709    appropriately given their state of initialization.  */
 710 static void
 711 read_original_filename (cpp_reader *pfile)
 712 {
 713   const cpp_token *token, *token1;
 714
 715   /* Lex ahead; if the first tokens are of the form # NUM, then
 716      process the directive, otherwise back up.  */
 717   token = _cpp_lex_direct (pfile);
 718   if (token->type == CPP_HASH)
 719     {
 720       pfile->state.in_directive = 1;
 721       token1 = _cpp_lex_direct (pfile);
 722       _cpp_backup_tokens (pfile, 1);
 723       pfile->state.in_directive = 0;
 724
 725       /* If it's a #line directive, handle it.  */
 726       if (token1->type == CPP_NUMBER
 727           && _cpp_handle_directive (pfile, token->flags & PREV_WHITE))
 728         {
 729           read_original_directory (pfile);
 730           return;
 731         }
 732     }
 733
 734   /* Backup as if nothing happened.  */
 735   _cpp_backup_tokens (pfile, 1);
 736 }
 737
 738 /* For preprocessed files, if the tokens following the first filename
 739    line is of the form # <line> "/path/name//", handle the
 740    directive so we know the original current directory.  */
 741 static void
 742 read_original_directory (cpp_reader *pfile)
 743 {
 744   const cpp_token *hash, *token;
 745
 746   /* Lex ahead; if the first tokens are of the form # NUM, then
 747      process the directive, otherwise back up.  */
 748   hash = _cpp_lex_direct (pfile);
 749   if (hash->type != CPP_HASH)
 750     {
 751       _cpp_backup_tokens (pfile, 1);
 752       return;
 753     }
 754
 755   token = _cpp_lex_direct (pfile);
 756
 757   if (token->type != CPP_NUMBER)
 758     {
 759       _cpp_backup_tokens (pfile, 2);
 760       return;
 761     }
 762
 763   token = _cpp_lex_direct (pfile);
 764
 765   if (token->type != CPP_STRING
 766       || ! (token->val.str.len >= 5
 767             && IS_DIR_SEPARATOR (token->val.str.text[token->val.str.len-2])
 768             && IS_DIR_SEPARATOR (token->val.str.text[token->val.str.len-3])))
 769     {
 770       _cpp_backup_tokens (pfile, 3);
 771       return;
 772     }
 773
 774   if (pfile->cb.dir_change)
 775     {
 776       char *debugdir = (char *) alloca (token->val.str.len - 3);
 777
 778       memcpy (debugdir, (const char *) token->val.str.text + 1,
 779               token->val.str.len - 4);
 780       debugdir[token->val.str.len - 4] = '\0';
 781
 782       pfile->cb.dir_change (pfile, debugdir);
 783     }
 784 }
 785
 786 /* This is called at the end of preprocessing.  It pops the last
 787    buffer and writes dependency output.
 788
 789    Maybe it should also reset state, such that you could call
 790    cpp_start_read with a new filename to restart processing.  */
 791 void
 792 cpp_finish (cpp_reader *pfile, FILE *deps_stream)
 793 {
 794   /* Warn about unused macros before popping the final buffer.  */
 795   if (CPP_OPTION (pfile, warn_unused_macros))
 796     cpp_forall_identifiers (pfile, _cpp_warn_if_unused_macro, NULL);
 797
 798   /* lex.c leaves the final buffer on the stack.  This it so that
 799      it returns an unending stream of CPP_EOFs to the client.  If we
 800      popped the buffer, we'd dereference a NULL buffer pointer and
 801      segfault.  It's nice to allow the client to do worry-free excess
 802      cpp_get_token calls.  */
 803   while (pfile->buffer)
 804     _cpp_pop_buffer (pfile);
 805
 806   if (CPP_OPTION (pfile, deps.style) != DEPS_NONE && deps_stream)
 807     deps_write (pfile->deps, deps_stream,
 808                 CPP_OPTION (pfile, deps.phony_targets), 72);
 809
 810   /* Report on headers that could use multiple include guards.  */
 811   if (CPP_OPTION (pfile, print_include_names))
 812     _cpp_report_missing_guards (pfile);
 813 }
 814
 815 static void
 816 post_options (cpp_reader *pfile)
 817 {
 818   /* -Wtraditional is not useful in C++ mode.  */
 819   if (CPP_OPTION (pfile, cplusplus))
 820     CPP_OPTION (pfile, cpp_warn_traditional) = 0;
 821
 822   /* Permanently disable macro expansion if we are rescanning
 823      preprocessed text.  Read preprocesed source in ISO mode.  */
 824   if (CPP_OPTION (pfile, preprocessed))
 825     {
 826       if (!CPP_OPTION (pfile, directives_only))
 827         pfile->state.prevent_expansion = 1;
 828       CPP_OPTION (pfile, traditional) = 0;
 829     }
 830
 831   if (CPP_OPTION (pfile, warn_trigraphs) == 2)
 832     CPP_OPTION (pfile, warn_trigraphs) = !CPP_OPTION (pfile, trigraphs);
 833
 834   if (CPP_OPTION (pfile, traditional))
 835     {
 836       CPP_OPTION (pfile, trigraphs) = 0;
 837       CPP_OPTION (pfile, warn_trigraphs) = 0;
 838     }
 839 }