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   /* STDC89   */  { 0,  0,  0,  0,  0,  1,  0,   0,   0,   0,    0,     0,     1,   0 },
 102   /* STDC94   */  { 0,  0,  0,  0,  0,  1,  1,   0,   0,   0,    0,     0,     1,   0 },
 103   /* STDC99   */  { 1,  0,  1,  1,  0,  1,  1,   0,   0,   0,    0,     0,     1,   0 },
 104   /* STDC11   */  { 1,  0,  1,  1,  1,  1,  1,   1,   0,   0,    0,     0,     1,   0 },
 105   /* GNUCXX   */  { 0,  1,  1,  1,  0,  0,  1,   0,   0,   0,    0,     0,     0,   0 },
 106   /* CXX98    */  { 0,  1,  0,  1,  0,  1,  1,   0,   0,   0,    0,     0,     1,   0 },
 107   /* GNUCXX11 */  { 1,  1,  1,  1,  1,  0,  1,   1,   1,   1,    0,     0,     0,   0 },
 108   /* CXX11    */  { 1,  1,  0,  1,  1,  1,  1,   1,   1,   1,    0,     0,     1,   0 },
 109   /* GNUCXX14 */  { 1,  1,  1,  1,  1,  0,  1,   1,   1,   1,    1,     1,     0,   0 },
 110   /* CXX14    */  { 1,  1,  0,  1,  1,  1,  1,   1,   1,   1,    1,     1,     1,   0 },
 111   /* GNUCXX1Z */  { 1,  1,  1,  1,  1,  0,  1,   1,   1,   1,    1,     1,     0,   1 },
 112   /* CXX1Z    */  { 1,  1,  1,  1,  1,  1,  1,   1,   1,   1,    1,     1,     0,   1 },
 113   /* ASM      */  { 0,  0,  1,  0,  0,  0,  0,   0,   0,   0,    0,     0,     0,   0 }
 114 };
 115
 116 /* Sets internal flags correctly for a given language.  */
 117 void
 118 cpp_set_lang (cpp_reader *pfile, enum c_lang lang)
 119 {
 120   const struct lang_flags *l = &lang_defaults[(int) lang];
 121
 122   CPP_OPTION (pfile, lang) = lang;
 123
 124   CPP_OPTION (pfile, c99)                        = l->c99;
 125   CPP_OPTION (pfile, cplusplus)                  = l->cplusplus;
 126   CPP_OPTION (pfile, extended_numbers)           = l->extended_numbers;
 127   CPP_OPTION (pfile, extended_identifiers)       = l->extended_identifiers;
 128   CPP_OPTION (pfile, c11_identifiers)            = l->c11_identifiers;
 129   CPP_OPTION (pfile, std)                        = l->std;
 130   CPP_OPTION (pfile, digraphs)                   = l->digraphs;
 131   CPP_OPTION (pfile, uliterals)                  = l->uliterals;
 132   CPP_OPTION (pfile, rliterals)                  = l->rliterals;
 133   CPP_OPTION (pfile, user_literals)              = l->user_literals;
 134   CPP_OPTION (pfile, binary_constants)           = l->binary_constants;
 135   CPP_OPTION (pfile, digit_separators)           = l->digit_separators;
 136   CPP_OPTION (pfile, trigraphs)                  = l->trigraphs;
 137   CPP_OPTION (pfile, utf8_char_literals)         = l->utf8_char_literals;
 138 }
 139
 140 /* Initialize library global state.  */
 141 static void
 142 init_library (void)
 143 {
 144   static int initialized = 0;
 145
 146   if (! initialized)
 147     {
 148       initialized = 1;
 149
 150       _cpp_init_lexer ();
 151
 152       /* Set up the trigraph map.  This doesn't need to do anything if
 153          we were compiled with a compiler that supports C99 designated
 154          initializers.  */
 155       init_trigraph_map ();
 156
 157 #ifdef ENABLE_NLS
 158        (void) bindtextdomain (PACKAGE, LOCALEDIR);
 159 #endif
 160     }
 161 }
 162
 163 /* Initialize a cpp_reader structure.  */
 164 cpp_reader *
 165 cpp_create_reader (enum c_lang lang, cpp_hash_table *table,
 166                    struct line_maps *line_table)
 167 {
 168   cpp_reader *pfile;
 169
 170   /* Initialize this instance of the library if it hasn't been already.  */
 171   init_library ();
 172
 173   pfile = XCNEW (cpp_reader);
 174   memset (&pfile->base_context, 0, sizeof (pfile->base_context));
 175
 176   cpp_set_lang (pfile, lang);
 177   CPP_OPTION (pfile, warn_multichar) = 1;
 178   CPP_OPTION (pfile, discard_comments) = 1;
 179   CPP_OPTION (pfile, discard_comments_in_macro_exp) = 1;
 180   CPP_OPTION (pfile, tabstop) = 8;
 181   CPP_OPTION (pfile, operator_names) = 1;
 182   CPP_OPTION (pfile, warn_trigraphs) = 2;
 183   CPP_OPTION (pfile, warn_endif_labels) = 1;
 184   CPP_OPTION (pfile, cpp_warn_c90_c99_compat) = -1;
 185   CPP_OPTION (pfile, cpp_warn_cxx11_compat) = 0;
 186   CPP_OPTION (pfile, cpp_warn_deprecated) = 1;
 187   CPP_OPTION (pfile, cpp_warn_long_long) = 0;
 188   CPP_OPTION (pfile, dollars_in_ident) = 1;
 189   CPP_OPTION (pfile, warn_dollars) = 1;
 190   CPP_OPTION (pfile, warn_variadic_macros) = 1;
 191   CPP_OPTION (pfile, warn_builtin_macro_redefined) = 1;
 192   CPP_OPTION (pfile, cpp_warn_implicit_fallthrough) = 0;
 193   /* By default, track locations of tokens resulting from macro
 194      expansion.  The '2' means, track the locations with the highest
 195      accuracy.  Read the comments for struct
 196      cpp_options::track_macro_expansion to learn about the other
 197      values.  */
 198   CPP_OPTION (pfile, track_macro_expansion) = 2;
 199   CPP_OPTION (pfile, warn_normalize) = normalized_C;
 200   CPP_OPTION (pfile, warn_literal_suffix) = 1;
 201   CPP_OPTION (pfile, canonical_system_headers)
 202       = ENABLE_CANONICAL_SYSTEM_HEADERS;
 203   CPP_OPTION (pfile, ext_numeric_literals) = 1;
 204   CPP_OPTION (pfile, warn_date_time) = 0;
 205
 206   /* Default CPP arithmetic to something sensible for the host for the
 207      benefit of dumb users like fix-header.  */
 208   CPP_OPTION (pfile, precision) = CHAR_BIT * sizeof (long);
 209   CPP_OPTION (pfile, char_precision) = CHAR_BIT;
 210   CPP_OPTION (pfile, wchar_precision) = CHAR_BIT * sizeof (int);
 211   CPP_OPTION (pfile, int_precision) = CHAR_BIT * sizeof (int);
 212   CPP_OPTION (pfile, unsigned_char) = 0;
 213   CPP_OPTION (pfile, unsigned_wchar) = 1;
 214   CPP_OPTION (pfile, bytes_big_endian) = 1;  /* does not matter */
 215
 216   /* Default to no charset conversion.  */
 217   CPP_OPTION (pfile, narrow_charset) = _cpp_default_encoding ();
 218   CPP_OPTION (pfile, wide_charset) = 0;
 219
 220   /* Default the input character set to UTF-8.  */
 221   CPP_OPTION (pfile, input_charset) = _cpp_default_encoding ();
 222
 223   /* A fake empty "directory" used as the starting point for files
 224      looked up without a search path.  Name cannot be '/' because we
 225      don't want to prepend anything at all to filenames using it.  All
 226      other entries are correct zero-initialized.  */
 227   pfile->no_search_path.name = (char *) "";
 228
 229   /* Initialize the line map.  */
 230   pfile->line_table = line_table;
 231
 232   /* Initialize lexer state.  */
 233   pfile->state.save_comments = ! CPP_OPTION (pfile, discard_comments);
 234
 235   /* Set up static tokens.  */
 236   pfile->avoid_paste.type = CPP_PADDING;
 237   pfile->avoid_paste.val.source = NULL;
 238   pfile->eof.type = CPP_EOF;
 239   pfile->eof.flags = 0;
 240
 241   /* Create a token buffer for the lexer.  */
 242   _cpp_init_tokenrun (&pfile->base_run, 250);
 243   pfile->cur_run = &pfile->base_run;
 244   pfile->cur_token = pfile->base_run.base;
 245
 246   /* Initialize the base context.  */
 247   pfile->context = &pfile->base_context;
 248   pfile->base_context.c.macro = 0;
 249   pfile->base_context.prev = pfile->base_context.next = 0;
 250
 251   /* Aligned and unaligned storage.  */
 252   pfile->a_buff = _cpp_get_buff (pfile, 0);
 253   pfile->u_buff = _cpp_get_buff (pfile, 0);
 254
 255   /* Initialize table for push_macro/pop_macro.  */
 256   pfile->pushed_macros = 0;
 257
 258   /* Do not force token locations by default.  */
 259   pfile->forced_token_location_p = NULL;
 260
 261   /* Initialize source_date_epoch to -2 (not yet set).  */
 262   pfile->source_date_epoch = (time_t) -2;
 263
 264   /* The expression parser stack.  */
 265   _cpp_expand_op_stack (pfile);
 266
 267   /* Initialize the buffer obstack.  */
 268   obstack_specify_allocation (&pfile->buffer_ob, 0, 0, xmalloc, free);
 269
 270   _cpp_init_files (pfile);
 271
 272   _cpp_init_hashtable (pfile, table);
 273
 274   return pfile;
 275 }
 276
 277 /* Set the line_table entry in PFILE.  This is called after reading a
 278    PCH file, as the old line_table will be incorrect.  */
 279 void
 280 cpp_set_line_map (cpp_reader *pfile, struct line_maps *line_table)
 281 {
 282   pfile->line_table = line_table;
 283 }
 284
 285 /* Free resources used by PFILE.  Accessing PFILE after this function
 286    returns leads to undefined behavior.  Returns the error count.  */
 287 void
 288 cpp_destroy (cpp_reader *pfile)
 289 {
 290   cpp_context *context, *contextn;
 291   struct def_pragma_macro *pmacro;
 292   tokenrun *run, *runn;
 293   int i;
 294
 295   free (pfile->op_stack);
 296
 297   while (CPP_BUFFER (pfile) != NULL)
 298     _cpp_pop_buffer (pfile);
 299
 300   free (pfile->out.base);
 301
 302   if (pfile->macro_buffer)
 303     {
 304       free (pfile->macro_buffer);
 305       pfile->macro_buffer = NULL;
 306       pfile->macro_buffer_len = 0;
 307     }
 308
 309   if (pfile->deps)
 310     deps_free (pfile->deps);
 311   obstack_free (&pfile->buffer_ob, 0);
 312
 313   _cpp_destroy_hashtable (pfile);
 314   _cpp_cleanup_files (pfile);
 315   _cpp_destroy_iconv (pfile);
 316
 317   _cpp_free_buff (pfile->a_buff);
 318   _cpp_free_buff (pfile->u_buff);
 319   _cpp_free_buff (pfile->free_buffs);
 320
 321   for (run = &pfile->base_run; run; run = runn)
 322     {
 323       runn = run->next;
 324       free (run->base);
 325       if (run != &pfile->base_run)
 326         free (run);
 327     }
 328
 329   for (context = pfile->base_context.next; context; context = contextn)
 330     {
 331       contextn = context->next;
 332       free (context);
 333     }
 334
 335   if (pfile->comments.entries)
 336     {
 337       for (i = 0; i < pfile->comments.count; i++)
 338         free (pfile->comments.entries[i].comment);
 339
 340       free (pfile->comments.entries);
 341     }
 342   if (pfile->pushed_macros)
 343     {
 344       do
 345         {
 346           pmacro = pfile->pushed_macros;
 347           pfile->pushed_macros = pmacro->next;
 348           free (pmacro->name);
 349           free (pmacro);
 350         }
 351       while (pfile->pushed_macros);
 352     }
 353
 354   free (pfile);
 355 }
 356
 357 /* This structure defines one built-in identifier.  A node will be
 358    entered in the hash table under the name NAME, with value VALUE.
 359
 360    There are two tables of these.  builtin_array holds all the
 361    "builtin" macros: these are handled by builtin_macro() in
 362    macro.c.  Builtin is somewhat of a misnomer -- the property of
 363    interest is that these macros require special code to compute their
 364    expansions.  The value is a "cpp_builtin_type" enumerator.
 365
 366    operator_array holds the C++ named operators.  These are keywords
 367    which act as aliases for punctuators.  In C++, they cannot be
 368    altered through #define, and #if recognizes them as operators.  In
 369    C, these are not entered into the hash table at all (but see
 370    <iso646.h>).  The value is a token-type enumerator.  */
 371 struct builtin_macro
 372 {
 373   const uchar *const name;
 374   const unsigned short len;
 375   const unsigned short value;
 376   const bool always_warn_if_redefined;
 377 };
 378
 379 #define B(n, t, f)    { DSC(n), t, f }
 380 static const struct builtin_macro builtin_array[] =
 381 {
 382   B("__TIMESTAMP__",     BT_TIMESTAMP,     false),
 383   B("__TIME__",          BT_TIME,          false),
 384   B("__DATE__",          BT_DATE,          false),
 385   B("__FILE__",          BT_FILE,          false),
 386   B("__BASE_FILE__",     BT_BASE_FILE,     false),
 387   B("__LINE__",          BT_SPECLINE,      true),
 388   B("__INCLUDE_LEVEL__", BT_INCLUDE_LEVEL, true),
 389   B("__COUNTER__",       BT_COUNTER,       true),
 390   B("__has_attribute",   BT_HAS_ATTRIBUTE, true),
 391   B("__has_cpp_attribute", BT_HAS_ATTRIBUTE, true),
 392   /* Keep builtins not used for -traditional-cpp at the end, and
 393      update init_builtins() if any more are added.  */
 394   B("_Pragma",           BT_PRAGMA,        true),
 395   B("__STDC__",          BT_STDC,          true),
 396 };
 397 #undef B
 398
 399 struct builtin_operator
 400 {
 401   const uchar *const name;
 402   const unsigned short len;
 403   const unsigned short value;
 404 };
 405
 406 #define B(n, t)    { DSC(n), t }
 407 static const struct builtin_operator operator_array[] =
 408 {
 409   B("and",      CPP_AND_AND),
 410   B("and_eq",   CPP_AND_EQ),
 411   B("bitand",   CPP_AND),
 412   B("bitor",    CPP_OR),
 413   B("compl",    CPP_COMPL),
 414   B("not",      CPP_NOT),
 415   B("not_eq",   CPP_NOT_EQ),
 416   B("or",       CPP_OR_OR),
 417   B("or_eq",    CPP_OR_EQ),
 418   B("xor",      CPP_XOR),
 419   B("xor_eq",   CPP_XOR_EQ)
 420 };
 421 #undef B
 422
 423 /* Mark the C++ named operators in the hash table.  */
 424 static void
 425 mark_named_operators (cpp_reader *pfile, int flags)
 426 {
 427   const struct builtin_operator *b;
 428
 429   for (b = operator_array;
 430        b < (operator_array + ARRAY_SIZE (operator_array));
 431        b++)
 432     {
 433       cpp_hashnode *hp = cpp_lookup (pfile, b->name, b->len);
 434       hp->flags |= flags;
 435       hp->is_directive = 0;
 436       hp->directive_index = b->value;
 437     }
 438 }
 439
 440 /* Helper function of cpp_type2name. Return the string associated with
 441    named operator TYPE.  */
 442 const char *
 443 cpp_named_operator2name (enum cpp_ttype type)
 444 {
 445   const struct builtin_operator *b;
 446
 447   for (b = operator_array;
 448        b < (operator_array + ARRAY_SIZE (operator_array));
 449        b++)
 450     {
 451       if (type == b->value)
 452         return (const char *) b->name;
 453     }
 454
 455   return NULL;
 456 }
 457
 458 void
 459 cpp_init_special_builtins (cpp_reader *pfile)
 460 {
 461   const struct builtin_macro *b;
 462   size_t n = ARRAY_SIZE (builtin_array);
 463
 464   if (CPP_OPTION (pfile, traditional))
 465     n -= 2;
 466   else if (! CPP_OPTION (pfile, stdc_0_in_system_headers)
 467            || CPP_OPTION (pfile, std))
 468     n--;
 469
 470   for (b = builtin_array; b < builtin_array + n; b++)
 471     {
 472       if (b->value == BT_HAS_ATTRIBUTE
 473           && (CPP_OPTION (pfile, lang) == CLK_ASM
 474               || pfile->cb.has_attribute == NULL))
 475         continue;
 476       cpp_hashnode *hp = cpp_lookup (pfile, b->name, b->len);
 477       hp->type = NT_MACRO;
 478       hp->flags |= NODE_BUILTIN;
 479       if (b->always_warn_if_redefined)
 480         hp->flags |= NODE_WARN;
 481       hp->value.builtin = (enum cpp_builtin_type) b->value;
 482     }
 483 }
 484
 485 /* Read the builtins table above and enter them, and language-specific
 486    macros, into the hash table.  HOSTED is true if this is a hosted
 487    environment.  */
 488 void
 489 cpp_init_builtins (cpp_reader *pfile, int hosted)
 490 {
 491   cpp_init_special_builtins (pfile);
 492
 493   if (!CPP_OPTION (pfile, traditional)
 494       && (! CPP_OPTION (pfile, stdc_0_in_system_headers)
 495           || CPP_OPTION (pfile, std)))
 496     _cpp_define_builtin (pfile, "__STDC__ 1");
 497
 498   if (CPP_OPTION (pfile, cplusplus))
 499     {
 500       if (CPP_OPTION (pfile, lang) == CLK_CXX1Z
 501           || CPP_OPTION (pfile, lang) == CLK_GNUCXX1Z)
 502         _cpp_define_builtin (pfile, "__cplusplus 201703L");
 503       else if (CPP_OPTION (pfile, lang) == CLK_CXX14
 504           || CPP_OPTION (pfile, lang) == CLK_GNUCXX14)
 505         _cpp_define_builtin (pfile, "__cplusplus 201402L");
 506       else if (CPP_OPTION (pfile, lang) == CLK_CXX11
 507                || CPP_OPTION (pfile, lang) == CLK_GNUCXX11)
 508         _cpp_define_builtin (pfile, "__cplusplus 201103L");
 509       else
 510         _cpp_define_builtin (pfile, "__cplusplus 199711L");
 511     }
 512   else if (CPP_OPTION (pfile, lang) == CLK_ASM)
 513     _cpp_define_builtin (pfile, "__ASSEMBLER__ 1");
 514   else if (CPP_OPTION (pfile, lang) == CLK_STDC94)
 515     _cpp_define_builtin (pfile, "__STDC_VERSION__ 199409L");
 516   else if (CPP_OPTION (pfile, lang) == CLK_STDC11
 517            || CPP_OPTION (pfile, lang) == CLK_GNUC11)
 518     _cpp_define_builtin (pfile, "__STDC_VERSION__ 201112L");
 519   else if (CPP_OPTION (pfile, c99))
 520     _cpp_define_builtin (pfile, "__STDC_VERSION__ 199901L");
 521
 522   if (CPP_OPTION (pfile, uliterals)
 523       && !(CPP_OPTION (pfile, cplusplus)
 524            && (CPP_OPTION (pfile, lang) == CLK_GNUCXX
 525             || CPP_OPTION (pfile, lang) == CLK_CXX98)))
 526     {
 527       _cpp_define_builtin (pfile, "__STDC_UTF_16__ 1");
 528       _cpp_define_builtin (pfile, "__STDC_UTF_32__ 1");
 529     }
 530
 531   if (hosted)
 532     _cpp_define_builtin (pfile, "__STDC_HOSTED__ 1");
 533   else
 534     _cpp_define_builtin (pfile, "__STDC_HOSTED__ 0");
 535
 536   if (CPP_OPTION (pfile, objc))
 537     _cpp_define_builtin (pfile, "__OBJC__ 1");
 538 }
 539
 540 /* Sanity-checks are dependent on command-line options, so it is
 541    called as a subroutine of cpp_read_main_file.  */
 542 #if CHECKING_P
 543 static void sanity_checks (cpp_reader *);
 544 static void sanity_checks (cpp_reader *pfile)
 545 {
 546   cppchar_t test = 0;
 547   size_t max_precision = 2 * CHAR_BIT * sizeof (cpp_num_part);
 548
 549   /* Sanity checks for assumptions about CPP arithmetic and target
 550      type precisions made by cpplib.  */
 551   test--;
 552   if (test < 1)
 553     cpp_error (pfile, CPP_DL_ICE, "cppchar_t must be an unsigned type");
 554
 555   if (CPP_OPTION (pfile, precision) > max_precision)
 556     cpp_error (pfile, CPP_DL_ICE,
 557                "preprocessor arithmetic has maximum precision of %lu bits;"
 558                " target requires %lu bits",
 559                (unsigned long) max_precision,
 560                (unsigned long) CPP_OPTION (pfile, precision));
 561
 562   if (CPP_OPTION (pfile, precision) < CPP_OPTION (pfile, int_precision))
 563     cpp_error (pfile, CPP_DL_ICE,
 564                "CPP arithmetic must be at least as precise as a target int");
 565
 566   if (CPP_OPTION (pfile, char_precision) < 8)
 567     cpp_error (pfile, CPP_DL_ICE, "target char is less than 8 bits wide");
 568
 569   if (CPP_OPTION (pfile, wchar_precision) < CPP_OPTION (pfile, char_precision))
 570     cpp_error (pfile, CPP_DL_ICE,
 571                "target wchar_t is narrower than target char");
 572
 573   if (CPP_OPTION (pfile, int_precision) < CPP_OPTION (pfile, char_precision))
 574     cpp_error (pfile, CPP_DL_ICE,
 575                "target int is narrower than target char");
 576
 577   /* This is assumed in eval_token() and could be fixed if necessary.  */
 578   if (sizeof (cppchar_t) > sizeof (cpp_num_part))
 579     cpp_error (pfile, CPP_DL_ICE,
 580                "CPP half-integer narrower than CPP character");
 581
 582   if (CPP_OPTION (pfile, wchar_precision) > BITS_PER_CPPCHAR_T)
 583     cpp_error (pfile, CPP_DL_ICE,
 584                "CPP on this host cannot handle wide character constants over"
 585                " %lu bits, but the target requires %lu bits",
 586                (unsigned long) BITS_PER_CPPCHAR_T,
 587                (unsigned long) CPP_OPTION (pfile, wchar_precision));
 588 }
 589 #else
 590 # define sanity_checks(PFILE)
 591 #endif
 592
 593 /* This is called after options have been parsed, and partially
 594    processed.  */
 595 void
 596 cpp_post_options (cpp_reader *pfile)
 597 {
 598   int flags;
 599
 600   sanity_checks (pfile);
 601
 602   post_options (pfile);
 603
 604   /* Mark named operators before handling command line macros.  */
 605   flags = 0;
 606   if (CPP_OPTION (pfile, cplusplus) && CPP_OPTION (pfile, operator_names))
 607     flags |= NODE_OPERATOR;
 608   if (CPP_OPTION (pfile, warn_cxx_operator_names))
 609     flags |= NODE_DIAGNOSTIC | NODE_WARN_OPERATOR;
 610   if (flags != 0)
 611     mark_named_operators (pfile, flags);
 612 }
 613
 614 /* Setup for processing input from the file named FNAME, or stdin if
 615    it is the empty string.  Return the original filename
 616    on success (e.g. foo.i->foo.c), or NULL on failure.  */
 617 const char *
 618 cpp_read_main_file (cpp_reader *pfile, const char *fname)
 619 {
 620   const source_location loc = 0;
 621
 622   if (CPP_OPTION (pfile, deps.style) != DEPS_NONE)
 623     {
 624       if (!pfile->deps)
 625         pfile->deps = deps_init ();
 626
 627       /* Set the default target (if there is none already).  */
 628       deps_add_default_target (pfile->deps, fname);
 629     }
 630
 631   pfile->main_file
 632     = _cpp_find_file (pfile, fname, &pfile->no_search_path, false, 0, false,
 633                       loc);
 634   if (_cpp_find_failed (pfile->main_file))
 635     return NULL;
 636
 637   _cpp_stack_file (pfile, pfile->main_file, false, loc);
 638
 639   /* For foo.i, read the original filename foo.c now, for the benefit
 640      of the front ends.  */
 641   if (CPP_OPTION (pfile, preprocessed))
 642     {
 643       read_original_filename (pfile);
 644       fname =
 645         ORDINARY_MAP_FILE_NAME
 646         ((LINEMAPS_LAST_ORDINARY_MAP (pfile->line_table)));
 647     }
 648   return fname;
 649 }
 650
 651 /* For preprocessed files, if the first tokens are of the form # NUM.
 652    handle the directive so we know the original file name.  This will
 653    generate file_change callbacks, which the front ends must handle
 654    appropriately given their state of initialization.  */
 655 static void
 656 read_original_filename (cpp_reader *pfile)
 657 {
 658   const cpp_token *token, *token1;
 659
 660   /* Lex ahead; if the first tokens are of the form # NUM, then
 661      process the directive, otherwise back up.  */
 662   token = _cpp_lex_direct (pfile);
 663   if (token->type == CPP_HASH)
 664     {
 665       pfile->state.in_directive = 1;
 666       token1 = _cpp_lex_direct (pfile);
 667       _cpp_backup_tokens (pfile, 1);
 668       pfile->state.in_directive = 0;
 669
 670       /* If it's a #line directive, handle it.  */
 671       if (token1->type == CPP_NUMBER
 672           && _cpp_handle_directive (pfile, token->flags & PREV_WHITE))
 673         {
 674           read_original_directory (pfile);
 675           return;
 676         }
 677     }
 678
 679   /* Backup as if nothing happened.  */
 680   _cpp_backup_tokens (pfile, 1);
 681 }
 682
 683 /* For preprocessed files, if the tokens following the first filename
 684    line is of the form # <line> "/path/name//", handle the
 685    directive so we know the original current directory.  */
 686 static void
 687 read_original_directory (cpp_reader *pfile)
 688 {
 689   const cpp_token *hash, *token;
 690
 691   /* Lex ahead; if the first tokens are of the form # NUM, then
 692      process the directive, otherwise back up.  */
 693   hash = _cpp_lex_direct (pfile);
 694   if (hash->type != CPP_HASH)
 695     {
 696       _cpp_backup_tokens (pfile, 1);
 697       return;
 698     }
 699
 700   token = _cpp_lex_direct (pfile);
 701
 702   if (token->type != CPP_NUMBER)
 703     {
 704       _cpp_backup_tokens (pfile, 2);
 705       return;
 706     }
 707
 708   token = _cpp_lex_direct (pfile);
 709
 710   if (token->type != CPP_STRING
 711       || ! (token->val.str.len >= 5
 712             && IS_DIR_SEPARATOR (token->val.str.text[token->val.str.len-2])
 713             && IS_DIR_SEPARATOR (token->val.str.text[token->val.str.len-3])))
 714     {
 715       _cpp_backup_tokens (pfile, 3);
 716       return;
 717     }
 718
 719   if (pfile->cb.dir_change)
 720     {
 721       char *debugdir = (char *) alloca (token->val.str.len - 3);
 722
 723       memcpy (debugdir, (const char *) token->val.str.text + 1,
 724               token->val.str.len - 4);
 725       debugdir[token->val.str.len - 4] = '\0';
 726
 727       pfile->cb.dir_change (pfile, debugdir);
 728     }
 729 }
 730
 731 /* This is called at the end of preprocessing.  It pops the last
 732    buffer and writes dependency output.
 733
 734    Maybe it should also reset state, such that you could call
 735    cpp_start_read with a new filename to restart processing.  */
 736 void
 737 cpp_finish (cpp_reader *pfile, FILE *deps_stream)
 738 {
 739   /* Warn about unused macros before popping the final buffer.  */
 740   if (CPP_OPTION (pfile, warn_unused_macros))
 741     cpp_forall_identifiers (pfile, _cpp_warn_if_unused_macro, NULL);
 742
 743   /* lex.c leaves the final buffer on the stack.  This it so that
 744      it returns an unending stream of CPP_EOFs to the client.  If we
 745      popped the buffer, we'd dereference a NULL buffer pointer and
 746      segfault.  It's nice to allow the client to do worry-free excess
 747      cpp_get_token calls.  */
 748   while (pfile->buffer)
 749     _cpp_pop_buffer (pfile);
 750
 751   if (CPP_OPTION (pfile, deps.style) != DEPS_NONE
 752       && deps_stream)
 753     {
 754       deps_write (pfile->deps, deps_stream, 72);
 755
 756       if (CPP_OPTION (pfile, deps.phony_targets))
 757         deps_phony_targets (pfile->deps, deps_stream);
 758     }
 759
 760   /* Report on headers that could use multiple include guards.  */
 761   if (CPP_OPTION (pfile, print_include_names))
 762     _cpp_report_missing_guards (pfile);
 763 }
 764
 765 static void
 766 post_options (cpp_reader *pfile)
 767 {
 768   /* -Wtraditional is not useful in C++ mode.  */
 769   if (CPP_OPTION (pfile, cplusplus))
 770     CPP_OPTION (pfile, cpp_warn_traditional) = 0;
 771
 772   /* Permanently disable macro expansion if we are rescanning
 773      preprocessed text.  Read preprocesed source in ISO mode.  */
 774   if (CPP_OPTION (pfile, preprocessed))
 775     {
 776       if (!CPP_OPTION (pfile, directives_only))
 777         pfile->state.prevent_expansion = 1;
 778       CPP_OPTION (pfile, traditional) = 0;
 779     }
 780
 781   if (CPP_OPTION (pfile, warn_trigraphs) == 2)
 782     CPP_OPTION (pfile, warn_trigraphs) = !CPP_OPTION (pfile, trigraphs);
 783
 784   if (CPP_OPTION (pfile, traditional))
 785     {
 786       CPP_OPTION (pfile, trigraphs) = 0;
 787       CPP_OPTION (pfile, warn_trigraphs) = 0;
 788     }
 789 }