libcpp/init.c

   1 /* CPP Library.
   2    Copyright (C) 1986-2017 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 };
  95
  96 static const struct lang_flags lang_defaults[] =
  97 { /*              c99 c++ xnum xid c11 std digr ulit rlit udlit bincst digsep trig u8chlit */
  98   /* GNUC89   */  { 0,  0,  1,  0,  0,  0,  1,   0,   0,   0,    0,     0,     0,   0 },
  99   /* GNUC99   */  { 1,  0,  1,  1,  0,  0,  1,   1,   1,   0,    0,     0,     0,   0 },
 100   /* GNUC11   */  { 1,  0,  1,  1,  1,  0,  1,   1,   1,   0,    0,     0,     0,   0 },
 101   /* GNUC17   */  { 1,  0,  1,  1,  1,  0,  1,   1,   1,   0,    0,     0,     0,   0 },
 102   /* STDC89   */  { 0,  0,  0,  0,  0,  1,  0,   0,   0,   0,    0,     0,     1,   0 },
 103   /* STDC94   */  { 0,  0,  0,  0,  0,  1,  1,   0,   0,   0,    0,     0,     1,   0 },
 104   /* STDC99   */  { 1,  0,  1,  1,  0,  1,  1,   0,   0,   0,    0,     0,     1,   0 },
 105   /* STDC11   */  { 1,  0,  1,  1,  1,  1,  1,   1,   0,   0,    0,     0,     1,   0 },
 106   /* STDC17   */  { 1,  0,  1,  1,  1,  1,  1,   1,   0,   0,    0,     0,     1,   0 },
 107   /* GNUCXX   */  { 0,  1,  1,  1,  0,  0,  1,   0,   0,   0,    0,     0,     0,   0 },
 108   /* CXX98    */  { 0,  1,  0,  1,  0,  1,  1,   0,   0,   0,    0,     0,     1,   0 },
 109   /* GNUCXX11 */  { 1,  1,  1,  1,  1,  0,  1,   1,   1,   1,    0,     0,     0,   0 },
 110   /* CXX11    */  { 1,  1,  0,  1,  1,  1,  1,   1,   1,   1,    0,     0,     1,   0 },
 111   /* GNUCXX14 */  { 1,  1,  1,  1,  1,  0,  1,   1,   1,   1,    1,     1,     0,   0 },
 112   /* CXX14    */  { 1,  1,  0,  1,  1,  1,  1,   1,   1,   1,    1,     1,     1,   0 },
 113   /* GNUCXX17 */  { 1,  1,  1,  1,  1,  0,  1,   1,   1,   1,    1,     1,     0,   1 },
 114   /* CXX17    */  { 1,  1,  1,  1,  1,  1,  1,   1,   1,   1,    1,     1,     0,   1 },
 115   /* GNUCXX2A */  { 1,  1,  1,  1,  1,  0,  1,   1,   1,   1,    1,     1,     0,   1 },
 116   /* CXX2A    */  { 1,  1,  1,  1,  1,  1,  1,   1,   1,   1,    1,     1,     0,   1 },
 117   /* ASM      */  { 0,  0,  1,  0,  0,  0,  0,   0,   0,   0,    0,     0,     0,   0 }
 118 };
 119
 120 /* Sets internal flags correctly for a given language.  */
 121 void
 122 cpp_set_lang (cpp_reader *pfile, enum c_lang lang)
 123 {
 124   const struct lang_flags *l = &lang_defaults[(int) lang];
 125
 126   CPP_OPTION (pfile, lang) = lang;
 127
 128   CPP_OPTION (pfile, c99)                        = l->c99;
 129   CPP_OPTION (pfile, cplusplus)                  = l->cplusplus;
 130   CPP_OPTION (pfile, extended_numbers)           = l->extended_numbers;
 131   CPP_OPTION (pfile, extended_identifiers)       = l->extended_identifiers;
 132   CPP_OPTION (pfile, c11_identifiers)            = l->c11_identifiers;
 133   CPP_OPTION (pfile, std)                        = l->std;
 134   CPP_OPTION (pfile, digraphs)                   = l->digraphs;
 135   CPP_OPTION (pfile, uliterals)                  = l->uliterals;
 136   CPP_OPTION (pfile, rliterals)                  = l->rliterals;
 137   CPP_OPTION (pfile, user_literals)              = l->user_literals;
 138   CPP_OPTION (pfile, binary_constants)           = l->binary_constants;
 139   CPP_OPTION (pfile, digit_separators)           = l->digit_separators;
 140   CPP_OPTION (pfile, trigraphs)                  = l->trigraphs;
 141   CPP_OPTION (pfile, utf8_char_literals)         = l->utf8_char_literals;
 142 }
 143
 144 /* Initialize library global state.  */
 145 static void
 146 init_library (void)
 147 {
 148   static int initialized = 0;
 149
 150   if (! initialized)
 151     {
 152       initialized = 1;
 153
 154       _cpp_init_lexer ();
 155
 156       /* Set up the trigraph map.  This doesn't need to do anything if
 157          we were compiled with a compiler that supports C99 designated
 158          initializers.  */
 159       init_trigraph_map ();
 160
 161 #ifdef ENABLE_NLS
 162        (void) bindtextdomain (PACKAGE, LOCALEDIR);
 163 #endif
 164     }
 165 }
 166
 167 /* Initialize a cpp_reader structure.  */
 168 cpp_reader *
 169 cpp_create_reader (enum c_lang lang, cpp_hash_table *table,
 170                    struct line_maps *line_table)
 171 {
 172   cpp_reader *pfile;
 173
 174   /* Initialize this instance of the library if it hasn't been already.  */
 175   init_library ();
 176
 177   pfile = XCNEW (cpp_reader);
 178   memset (&pfile->base_context, 0, sizeof (pfile->base_context));
 179
 180   cpp_set_lang (pfile, lang);
 181   CPP_OPTION (pfile, warn_multichar) = 1;
 182   CPP_OPTION (pfile, discard_comments) = 1;
 183   CPP_OPTION (pfile, discard_comments_in_macro_exp) = 1;
 184   CPP_OPTION (pfile, tabstop) = 8;
 185   CPP_OPTION (pfile, operator_names) = 1;
 186   CPP_OPTION (pfile, warn_trigraphs) = 2;
 187   CPP_OPTION (pfile, warn_endif_labels) = 1;
 188   CPP_OPTION (pfile, cpp_warn_c90_c99_compat) = -1;
 189   CPP_OPTION (pfile, cpp_warn_cxx11_compat) = 0;
 190   CPP_OPTION (pfile, cpp_warn_deprecated) = 1;
 191   CPP_OPTION (pfile, cpp_warn_long_long) = 0;
 192   CPP_OPTION (pfile, dollars_in_ident) = 1;
 193   CPP_OPTION (pfile, warn_dollars) = 1;
 194   CPP_OPTION (pfile, warn_variadic_macros) = 1;
 195   CPP_OPTION (pfile, warn_builtin_macro_redefined) = 1;
 196   CPP_OPTION (pfile, cpp_warn_implicit_fallthrough) = 0;
 197   /* By default, track locations of tokens resulting from macro
 198      expansion.  The '2' means, track the locations with the highest
 199      accuracy.  Read the comments for struct
 200      cpp_options::track_macro_expansion to learn about the other
 201      values.  */
 202   CPP_OPTION (pfile, track_macro_expansion) = 2;
 203   CPP_OPTION (pfile, warn_normalize) = normalized_C;
 204   CPP_OPTION (pfile, warn_literal_suffix) = 1;
 205   CPP_OPTION (pfile, canonical_system_headers)
 206       = ENABLE_CANONICAL_SYSTEM_HEADERS;
 207   CPP_OPTION (pfile, ext_numeric_literals) = 1;
 208   CPP_OPTION (pfile, warn_date_time) = 0;
 209
 210   /* Default CPP arithmetic to something sensible for the host for the
 211      benefit of dumb users like fix-header.  */
 212   CPP_OPTION (pfile, precision) = CHAR_BIT * sizeof (long);
 213   CPP_OPTION (pfile, char_precision) = CHAR_BIT;
 214   CPP_OPTION (pfile, wchar_precision) = CHAR_BIT * sizeof (int);
 215   CPP_OPTION (pfile, int_precision) = CHAR_BIT * sizeof (int);
 216   CPP_OPTION (pfile, unsigned_char) = 0;
 217   CPP_OPTION (pfile, unsigned_wchar) = 1;
 218   CPP_OPTION (pfile, bytes_big_endian) = 1;  /* does not matter */
 219
 220   /* Default to no charset conversion.  */
 221   CPP_OPTION (pfile, narrow_charset) = _cpp_default_encoding ();
 222   CPP_OPTION (pfile, wide_charset) = 0;
 223
 224   /* Default the input character set to UTF-8.  */
 225   CPP_OPTION (pfile, input_charset) = _cpp_default_encoding ();
 226
 227   /* A fake empty "directory" used as the starting point for files
 228      looked up without a search path.  Name cannot be '/' because we
 229      don't want to prepend anything at all to filenames using it.  All
 230      other entries are correct zero-initialized.  */
 231   pfile->no_search_path.name = (char *) "";
 232
 233   /* Initialize the line map.  */
 234   pfile->line_table = line_table;
 235
 236   /* Initialize lexer state.  */
 237   pfile->state.save_comments = ! CPP_OPTION (pfile, discard_comments);
 238
 239   /* Set up static tokens.  */
 240   pfile->avoid_paste.type = CPP_PADDING;
 241   pfile->avoid_paste.val.source = NULL;
 242   pfile->eof.type = CPP_EOF;
 243   pfile->eof.flags = 0;
 244
 245   /* Create a token buffer for the lexer.  */
 246   _cpp_init_tokenrun (&pfile->base_run, 250);
 247   pfile->cur_run = &pfile->base_run;
 248   pfile->cur_token = pfile->base_run.base;
 249
 250   /* Initialize the base context.  */
 251   pfile->context = &pfile->base_context;
 252   pfile->base_context.c.macro = 0;
 253   pfile->base_context.prev = pfile->base_context.next = 0;
 254
 255   /* Aligned and unaligned storage.  */
 256   pfile->a_buff = _cpp_get_buff (pfile, 0);
 257   pfile->u_buff = _cpp_get_buff (pfile, 0);
 258
 259   /* Initialize table for push_macro/pop_macro.  */
 260   pfile->pushed_macros = 0;
 261
 262   /* Do not force token locations by default.  */
 263   pfile->forced_token_location_p = NULL;
 264
 265   /* Initialize source_date_epoch to -2 (not yet set).  */
 266   pfile->source_date_epoch = (time_t) -2;
 267
 268   /* The expression parser stack.  */
 269   _cpp_expand_op_stack (pfile);
 270
 271   /* Initialize the buffer obstack.  */
 272   obstack_specify_allocation (&pfile->buffer_ob, 0, 0, xmalloc, free);
 273
 274   _cpp_init_files (pfile);
 275
 276   _cpp_init_hashtable (pfile, table);
 277
 278   return pfile;
 279 }
 280
 281 /* Set the line_table entry in PFILE.  This is called after reading a
 282    PCH file, as the old line_table will be incorrect.  */
 283 void
 284 cpp_set_line_map (cpp_reader *pfile, struct line_maps *line_table)
 285 {
 286   pfile->line_table = line_table;
 287 }
 288
 289 /* Free resources used by PFILE.  Accessing PFILE after this function
 290    returns leads to undefined behavior.  Returns the error count.  */
 291 void
 292 cpp_destroy (cpp_reader *pfile)
 293 {
 294   cpp_context *context, *contextn;
 295   struct def_pragma_macro *pmacro;
 296   tokenrun *run, *runn;
 297   int i;
 298
 299   free (pfile->op_stack);
 300
 301   while (CPP_BUFFER (pfile) != NULL)
 302     _cpp_pop_buffer (pfile);
 303
 304   free (pfile->out.base);
 305
 306   if (pfile->macro_buffer)
 307     {
 308       free (pfile->macro_buffer);
 309       pfile->macro_buffer = NULL;
 310       pfile->macro_buffer_len = 0;
 311     }
 312
 313   if (pfile->deps)
 314     deps_free (pfile->deps);
 315   obstack_free (&pfile->buffer_ob, 0);
 316
 317   _cpp_destroy_hashtable (pfile);
 318   _cpp_cleanup_files (pfile);
 319   _cpp_destroy_iconv (pfile);
 320
 321   _cpp_free_buff (pfile->a_buff);
 322   _cpp_free_buff (pfile->u_buff);
 323   _cpp_free_buff (pfile->free_buffs);
 324
 325   for (run = &pfile->base_run; run; run = runn)
 326     {
 327       runn = run->next;
 328       free (run->base);
 329       if (run != &pfile->base_run)
 330         free (run);
 331     }
 332
 333   for (context = pfile->base_context.next; context; context = contextn)
 334     {
 335       contextn = context->next;
 336       free (context);
 337     }
 338
 339   if (pfile->comments.entries)
 340     {
 341       for (i = 0; i < pfile->comments.count; i++)
 342         free (pfile->comments.entries[i].comment);
 343
 344       free (pfile->comments.entries);
 345     }
 346   if (pfile->pushed_macros)
 347     {
 348       do
 349         {
 350           pmacro = pfile->pushed_macros;
 351           pfile->pushed_macros = pmacro->next;
 352           free (pmacro->name);
 353           free (pmacro);
 354         }
 355       while (pfile->pushed_macros);
 356     }
 357
 358   free (pfile);
 359 }
 360
 361 /* This structure defines one built-in identifier.  A node will be
 362    entered in the hash table under the name NAME, with value VALUE.
 363
 364    There are two tables of these.  builtin_array holds all the
 365    "builtin" macros: these are handled by builtin_macro() in
 366    macro.c.  Builtin is somewhat of a misnomer -- the property of
 367    interest is that these macros require special code to compute their
 368    expansions.  The value is a "cpp_builtin_type" enumerator.
 369
 370    operator_array holds the C++ named operators.  These are keywords
 371    which act as aliases for punctuators.  In C++, they cannot be
 372    altered through #define, and #if recognizes them as operators.  In
 373    C, these are not entered into the hash table at all (but see
 374    <iso646.h>).  The value is a token-type enumerator.  */
 375 struct builtin_macro
 376 {
 377   const uchar *const name;
 378   const unsigned short len;
 379   const unsigned short value;
 380   const bool always_warn_if_redefined;
 381 };
 382
 383 #define B(n, t, f)    { DSC(n), t, f }
 384 static const struct builtin_macro builtin_array[] =
 385 {
 386   B("__TIMESTAMP__",     BT_TIMESTAMP,     false),
 387   B("__TIME__",          BT_TIME,          false),
 388   B("__DATE__",          BT_DATE,          false),
 389   B("__FILE__",          BT_FILE,          false),
 390   B("__BASE_FILE__",     BT_BASE_FILE,     false),
 391   B("__LINE__",          BT_SPECLINE,      true),
 392   B("__INCLUDE_LEVEL__", BT_INCLUDE_LEVEL, true),
 393   B("__COUNTER__",       BT_COUNTER,       true),
 394   B("__has_attribute",   BT_HAS_ATTRIBUTE, true),
 395   B("__has_cpp_attribute", BT_HAS_ATTRIBUTE, true),
 396   /* Keep builtins not used for -traditional-cpp at the end, and
 397      update init_builtins() if any more are added.  */
 398   B("_Pragma",           BT_PRAGMA,        true),
 399   B("__STDC__",          BT_STDC,          true),
 400 };
 401 #undef B
 402
 403 struct builtin_operator
 404 {
 405   const uchar *const name;
 406   const unsigned short len;
 407   const unsigned short value;
 408 };
 409
 410 #define B(n, t)    { DSC(n), t }
 411 static const struct builtin_operator operator_array[] =
 412 {
 413   B("and",      CPP_AND_AND),
 414   B("and_eq",   CPP_AND_EQ),
 415   B("bitand",   CPP_AND),
 416   B("bitor",    CPP_OR),
 417   B("compl",    CPP_COMPL),
 418   B("not",      CPP_NOT),
 419   B("not_eq",   CPP_NOT_EQ),
 420   B("or",       CPP_OR_OR),
 421   B("or_eq",    CPP_OR_EQ),
 422   B("xor",      CPP_XOR),
 423   B("xor_eq",   CPP_XOR_EQ)
 424 };
 425 #undef B
 426
 427 /* Mark the C++ named operators in the hash table.  */
 428 static void
 429 mark_named_operators (cpp_reader *pfile, int flags)
 430 {
 431   const struct builtin_operator *b;
 432
 433   for (b = operator_array;
 434        b < (operator_array + ARRAY_SIZE (operator_array));
 435        b++)
 436     {
 437       cpp_hashnode *hp = cpp_lookup (pfile, b->name, b->len);
 438       hp->flags |= flags;
 439       hp->is_directive = 0;
 440       hp->directive_index = b->value;
 441     }
 442 }
 443
 444 /* Helper function of cpp_type2name. Return the string associated with
 445    named operator TYPE.  */
 446 const char *
 447 cpp_named_operator2name (enum cpp_ttype type)
 448 {
 449   const struct builtin_operator *b;
 450
 451   for (b = operator_array;
 452        b < (operator_array + ARRAY_SIZE (operator_array));
 453        b++)
 454     {
 455       if (type == b->value)
 456         return (const char *) b->name;
 457     }
 458
 459   return NULL;
 460 }
 461
 462 void
 463 cpp_init_special_builtins (cpp_reader *pfile)
 464 {
 465   const struct builtin_macro *b;
 466   size_t n = ARRAY_SIZE (builtin_array);
 467
 468   if (CPP_OPTION (pfile, traditional))
 469     n -= 2;
 470   else if (! CPP_OPTION (pfile, stdc_0_in_system_headers)
 471            || CPP_OPTION (pfile, std))
 472     n--;
 473
 474   for (b = builtin_array; b < builtin_array + n; b++)
 475     {
 476       if (b->value == BT_HAS_ATTRIBUTE
 477           && (CPP_OPTION (pfile, lang) == CLK_ASM
 478               || pfile->cb.has_attribute == NULL))
 479         continue;
 480       cpp_hashnode *hp = cpp_lookup (pfile, b->name, b->len);
 481       hp->type = NT_MACRO;
 482       hp->flags |= NODE_BUILTIN;
 483       if (b->always_warn_if_redefined)
 484         hp->flags |= NODE_WARN;
 485       hp->value.builtin = (enum cpp_builtin_type) b->value;
 486     }
 487 }
 488
 489 /* Read the builtins table above and enter them, and language-specific
 490    macros, into the hash table.  HOSTED is true if this is a hosted
 491    environment.  */
 492 void
 493 cpp_init_builtins (cpp_reader *pfile, int hosted)
 494 {
 495   cpp_init_special_builtins (pfile);
 496
 497   if (!CPP_OPTION (pfile, traditional)
 498       && (! CPP_OPTION (pfile, stdc_0_in_system_headers)
 499           || CPP_OPTION (pfile, std)))
 500     _cpp_define_builtin (pfile, "__STDC__ 1");
 501
 502   if (CPP_OPTION (pfile, cplusplus))
 503     {
 504       if (CPP_OPTION (pfile, lang) == CLK_CXX2A
 505           || CPP_OPTION (pfile, lang) == CLK_GNUCXX2A)
 506         _cpp_define_builtin (pfile, "__cplusplus 201709L");
 507       else if (CPP_OPTION (pfile, lang) == CLK_CXX17
 508           || CPP_OPTION (pfile, lang) == CLK_GNUCXX17)
 509         _cpp_define_builtin (pfile, "__cplusplus 201703L");
 510       else if (CPP_OPTION (pfile, lang) == CLK_CXX14
 511           || CPP_OPTION (pfile, lang) == CLK_GNUCXX14)
 512         _cpp_define_builtin (pfile, "__cplusplus 201402L");
 513       else if (CPP_OPTION (pfile, lang) == CLK_CXX11
 514                || CPP_OPTION (pfile, lang) == CLK_GNUCXX11)
 515         _cpp_define_builtin (pfile, "__cplusplus 201103L");
 516       else
 517         _cpp_define_builtin (pfile, "__cplusplus 199711L");
 518     }
 519   else if (CPP_OPTION (pfile, lang) == CLK_ASM)
 520     _cpp_define_builtin (pfile, "__ASSEMBLER__ 1");
 521   else if (CPP_OPTION (pfile, lang) == CLK_STDC94)
 522     _cpp_define_builtin (pfile, "__STDC_VERSION__ 199409L");
 523   else if (CPP_OPTION (pfile, lang) == CLK_STDC17
 524            || CPP_OPTION (pfile, lang) == CLK_GNUC17)
 525     _cpp_define_builtin (pfile, "__STDC_VERSION__ 201710L");
 526   else if (CPP_OPTION (pfile, lang) == CLK_STDC11
 527            || CPP_OPTION (pfile, lang) == CLK_GNUC11)
 528     _cpp_define_builtin (pfile, "__STDC_VERSION__ 201112L");
 529   else if (CPP_OPTION (pfile, c99))
 530     _cpp_define_builtin (pfile, "__STDC_VERSION__ 199901L");
 531
 532   if (CPP_OPTION (pfile, uliterals)
 533       && !(CPP_OPTION (pfile, cplusplus)
 534            && (CPP_OPTION (pfile, lang) == CLK_GNUCXX
 535             || CPP_OPTION (pfile, lang) == CLK_CXX98)))
 536     {
 537       _cpp_define_builtin (pfile, "__STDC_UTF_16__ 1");
 538       _cpp_define_builtin (pfile, "__STDC_UTF_32__ 1");
 539     }
 540
 541   if (hosted)
 542     _cpp_define_builtin (pfile, "__STDC_HOSTED__ 1");
 543   else
 544     _cpp_define_builtin (pfile, "__STDC_HOSTED__ 0");
 545
 546   if (CPP_OPTION (pfile, objc))
 547     _cpp_define_builtin (pfile, "__OBJC__ 1");
 548 }
 549
 550 /* Sanity-checks are dependent on command-line options, so it is
 551    called as a subroutine of cpp_read_main_file.  */
 552 #if CHECKING_P
 553 static void sanity_checks (cpp_reader *);
 554 static void sanity_checks (cpp_reader *pfile)
 555 {
 556   cppchar_t test = 0;
 557   size_t max_precision = 2 * CHAR_BIT * sizeof (cpp_num_part);
 558
 559   /* Sanity checks for assumptions about CPP arithmetic and target
 560      type precisions made by cpplib.  */
 561   test--;
 562   if (test < 1)
 563     cpp_error (pfile, CPP_DL_ICE, "cppchar_t must be an unsigned type");
 564
 565   if (CPP_OPTION (pfile, precision) > max_precision)
 566     cpp_error (pfile, CPP_DL_ICE,
 567                "preprocessor arithmetic has maximum precision of %lu bits;"
 568                " target requires %lu bits",
 569                (unsigned long) max_precision,
 570                (unsigned long) CPP_OPTION (pfile, precision));
 571
 572   if (CPP_OPTION (pfile, precision) < CPP_OPTION (pfile, int_precision))
 573     cpp_error (pfile, CPP_DL_ICE,
 574                "CPP arithmetic must be at least as precise as a target int");
 575
 576   if (CPP_OPTION (pfile, char_precision) < 8)
 577     cpp_error (pfile, CPP_DL_ICE, "target char is less than 8 bits wide");
 578
 579   if (CPP_OPTION (pfile, wchar_precision) < CPP_OPTION (pfile, char_precision))
 580     cpp_error (pfile, CPP_DL_ICE,
 581                "target wchar_t is narrower than target char");
 582
 583   if (CPP_OPTION (pfile, int_precision) < CPP_OPTION (pfile, char_precision))
 584     cpp_error (pfile, CPP_DL_ICE,
 585                "target int is narrower than target char");
 586
 587   /* This is assumed in eval_token() and could be fixed if necessary.  */
 588   if (sizeof (cppchar_t) > sizeof (cpp_num_part))
 589     cpp_error (pfile, CPP_DL_ICE,
 590                "CPP half-integer narrower than CPP character");
 591
 592   if (CPP_OPTION (pfile, wchar_precision) > BITS_PER_CPPCHAR_T)
 593     cpp_error (pfile, CPP_DL_ICE,
 594                "CPP on this host cannot handle wide character constants over"
 595                " %lu bits, but the target requires %lu bits",
 596                (unsigned long) BITS_PER_CPPCHAR_T,
 597                (unsigned long) CPP_OPTION (pfile, wchar_precision));
 598 }
 599 #else
 600 # define sanity_checks(PFILE)
 601 #endif
 602
 603 /* This is called after options have been parsed, and partially
 604    processed.  */
 605 void
 606 cpp_post_options (cpp_reader *pfile)
 607 {
 608   int flags;
 609
 610   sanity_checks (pfile);
 611
 612   post_options (pfile);
 613
 614   /* Mark named operators before handling command line macros.  */
 615   flags = 0;
 616   if (CPP_OPTION (pfile, cplusplus) && CPP_OPTION (pfile, operator_names))
 617     flags |= NODE_OPERATOR;
 618   if (CPP_OPTION (pfile, warn_cxx_operator_names))
 619     flags |= NODE_DIAGNOSTIC | NODE_WARN_OPERATOR;
 620   if (flags != 0)
 621     mark_named_operators (pfile, flags);
 622 }
 623
 624 /* Setup for processing input from the file named FNAME, or stdin if
 625    it is the empty string.  Return the original filename
 626    on success (e.g. foo.i->foo.c), or NULL on failure.  */
 627 const char *
 628 cpp_read_main_file (cpp_reader *pfile, const char *fname)
 629 {
 630   const source_location loc = 0;
 631
 632   if (CPP_OPTION (pfile, deps.style) != DEPS_NONE)
 633     {
 634       if (!pfile->deps)
 635         pfile->deps = deps_init ();
 636
 637       /* Set the default target (if there is none already).  */
 638       deps_add_default_target (pfile->deps, fname);
 639     }
 640
 641   pfile->main_file
 642     = _cpp_find_file (pfile, fname, &pfile->no_search_path, false, 0, false,
 643                       loc);
 644   if (_cpp_find_failed (pfile->main_file))
 645     return NULL;
 646
 647   _cpp_stack_file (pfile, pfile->main_file, false, loc);
 648
 649   /* For foo.i, read the original filename foo.c now, for the benefit
 650      of the front ends.  */
 651   if (CPP_OPTION (pfile, preprocessed))
 652     {
 653       read_original_filename (pfile);
 654       fname =
 655         ORDINARY_MAP_FILE_NAME
 656         ((LINEMAPS_LAST_ORDINARY_MAP (pfile->line_table)));
 657     }
 658   return fname;
 659 }
 660
 661 /* For preprocessed files, if the first tokens are of the form # NUM.
 662    handle the directive so we know the original file name.  This will
 663    generate file_change callbacks, which the front ends must handle
 664    appropriately given their state of initialization.  */
 665 static void
 666 read_original_filename (cpp_reader *pfile)
 667 {
 668   const cpp_token *token, *token1;
 669
 670   /* Lex ahead; if the first tokens are of the form # NUM, then
 671      process the directive, otherwise back up.  */
 672   token = _cpp_lex_direct (pfile);
 673   if (token->type == CPP_HASH)
 674     {
 675       pfile->state.in_directive = 1;
 676       token1 = _cpp_lex_direct (pfile);
 677       _cpp_backup_tokens (pfile, 1);
 678       pfile->state.in_directive = 0;
 679
 680       /* If it's a #line directive, handle it.  */
 681       if (token1->type == CPP_NUMBER
 682           && _cpp_handle_directive (pfile, token->flags & PREV_WHITE))
 683         {
 684           read_original_directory (pfile);
 685           return;
 686         }
 687     }
 688
 689   /* Backup as if nothing happened.  */
 690   _cpp_backup_tokens (pfile, 1);
 691 }
 692
 693 /* For preprocessed files, if the tokens following the first filename
 694    line is of the form # <line> "/path/name//", handle the
 695    directive so we know the original current directory.  */
 696 static void
 697 read_original_directory (cpp_reader *pfile)
 698 {
 699   const cpp_token *hash, *token;
 700
 701   /* Lex ahead; if the first tokens are of the form # NUM, then
 702      process the directive, otherwise back up.  */
 703   hash = _cpp_lex_direct (pfile);
 704   if (hash->type != CPP_HASH)
 705     {
 706       _cpp_backup_tokens (pfile, 1);
 707       return;
 708     }
 709
 710   token = _cpp_lex_direct (pfile);
 711
 712   if (token->type != CPP_NUMBER)
 713     {
 714       _cpp_backup_tokens (pfile, 2);
 715       return;
 716     }
 717
 718   token = _cpp_lex_direct (pfile);
 719
 720   if (token->type != CPP_STRING
 721       || ! (token->val.str.len >= 5
 722             && IS_DIR_SEPARATOR (token->val.str.text[token->val.str.len-2])
 723             && IS_DIR_SEPARATOR (token->val.str.text[token->val.str.len-3])))
 724     {
 725       _cpp_backup_tokens (pfile, 3);
 726       return;
 727     }
 728
 729   if (pfile->cb.dir_change)
 730     {
 731       char *debugdir = (char *) alloca (token->val.str.len - 3);
 732
 733       memcpy (debugdir, (const char *) token->val.str.text + 1,
 734               token->val.str.len - 4);
 735       debugdir[token->val.str.len - 4] = '\0';
 736
 737       pfile->cb.dir_change (pfile, debugdir);
 738     }
 739 }
 740
 741 /* This is called at the end of preprocessing.  It pops the last
 742    buffer and writes dependency output.
 743
 744    Maybe it should also reset state, such that you could call
 745    cpp_start_read with a new filename to restart processing.  */
 746 void
 747 cpp_finish (cpp_reader *pfile, FILE *deps_stream)
 748 {
 749   /* Warn about unused macros before popping the final buffer.  */
 750   if (CPP_OPTION (pfile, warn_unused_macros))
 751     cpp_forall_identifiers (pfile, _cpp_warn_if_unused_macro, NULL);
 752
 753   /* lex.c leaves the final buffer on the stack.  This it so that
 754      it returns an unending stream of CPP_EOFs to the client.  If we
 755      popped the buffer, we'd dereference a NULL buffer pointer and
 756      segfault.  It's nice to allow the client to do worry-free excess
 757      cpp_get_token calls.  */
 758   while (pfile->buffer)
 759     _cpp_pop_buffer (pfile);
 760
 761   if (CPP_OPTION (pfile, deps.style) != DEPS_NONE
 762       && deps_stream)
 763     {
 764       deps_write (pfile->deps, deps_stream, 72);
 765
 766       if (CPP_OPTION (pfile, deps.phony_targets))
 767         deps_phony_targets (pfile->deps, deps_stream);
 768     }
 769
 770   /* Report on headers that could use multiple include guards.  */
 771   if (CPP_OPTION (pfile, print_include_names))
 772     _cpp_report_missing_guards (pfile);
 773 }
 774
 775 static void
 776 post_options (cpp_reader *pfile)
 777 {
 778   /* -Wtraditional is not useful in C++ mode.  */
 779   if (CPP_OPTION (pfile, cplusplus))
 780     CPP_OPTION (pfile, cpp_warn_traditional) = 0;
 781
 782   /* Permanently disable macro expansion if we are rescanning
 783      preprocessed text.  Read preprocesed source in ISO mode.  */
 784   if (CPP_OPTION (pfile, preprocessed))
 785     {
 786       if (!CPP_OPTION (pfile, directives_only))
 787         pfile->state.prevent_expansion = 1;
 788       CPP_OPTION (pfile, traditional) = 0;
 789     }
 790
 791   if (CPP_OPTION (pfile, warn_trigraphs) == 2)
 792     CPP_OPTION (pfile, warn_trigraphs) = !CPP_OPTION (pfile, trigraphs);
 793
 794   if (CPP_OPTION (pfile, traditional))
 795     {
 796       CPP_OPTION (pfile, trigraphs) = 0;
 797       CPP_OPTION (pfile, warn_trigraphs) = 0;
 798     }
 799 }