libcpp/init.c

   1 /* CPP Library.
   2    Copyright (C) 1986-2015 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 };
  94
  95 static const struct lang_flags lang_defaults[] =
  96 { /*              c99 c++ xnum xid c11 std digr ulit rlit udlit bincst digsep trig */
  97   /* GNUC89   */  { 0,  0,  1,  0,  0,  0,  1,   0,   0,   0,    0,     0,     0 },
  98   /* GNUC99   */  { 1,  0,  1,  1,  0,  0,  1,   1,   1,   0,    0,     0,     0 },
  99   /* GNUC11   */  { 1,  0,  1,  1,  1,  0,  1,   1,   1,   0,    0,     0,     0 },
 100   /* STDC89   */  { 0,  0,  0,  0,  0,  1,  0,   0,   0,   0,    0,     0,     1 },
 101   /* STDC94   */  { 0,  0,  0,  0,  0,  1,  1,   0,   0,   0,    0,     0,     1 },
 102   /* STDC99   */  { 1,  0,  1,  1,  0,  1,  1,   0,   0,   0,    0,     0,     1 },
 103   /* STDC11   */  { 1,  0,  1,  1,  1,  1,  1,   1,   0,   0,    0,     0,     1 },
 104   /* GNUCXX   */  { 0,  1,  1,  1,  0,  0,  1,   0,   0,   0,    0,     0,     0 },
 105   /* CXX98    */  { 0,  1,  0,  1,  0,  1,  1,   0,   0,   0,    0,     0,     1 },
 106   /* GNUCXX11 */  { 1,  1,  1,  1,  1,  0,  1,   1,   1,   1,    0,     0,     0 },
 107   /* CXX11    */  { 1,  1,  1,  1,  1,  1,  1,   1,   1,   1,    0,     0,     1 },
 108   /* GNUCXX14 */  { 1,  1,  1,  1,  1,  0,  1,   1,   1,   1,    1,     1,     0 },
 109   /* CXX14    */  { 1,  1,  1,  1,  1,  1,  1,   1,   1,   1,    1,     1,     1 },
 110   /* GNUCXX1Z */  { 1,  1,  1,  1,  1,  0,  1,   1,   1,   1,    1,     1,     0 },
 111   /* CXX1Z    */  { 1,  1,  1,  1,  1,  1,  1,   1,   1,   1,    1,     1,     0 },
 112   /* ASM      */  { 0,  0,  1,  0,  0,  0,  0,   0,   0,   0,    0,     0,     0 }
 113 };
 114
 115 /* Sets internal flags correctly for a given language.  */
 116 void
 117 cpp_set_lang (cpp_reader *pfile, enum c_lang lang)
 118 {
 119   const struct lang_flags *l = &lang_defaults[(int) lang];
 120
 121   CPP_OPTION (pfile, lang) = lang;
 122
 123   CPP_OPTION (pfile, c99)                        = l->c99;
 124   CPP_OPTION (pfile, cplusplus)                  = l->cplusplus;
 125   CPP_OPTION (pfile, extended_numbers)           = l->extended_numbers;
 126   CPP_OPTION (pfile, extended_identifiers)       = l->extended_identifiers;
 127   CPP_OPTION (pfile, c11_identifiers)            = l->c11_identifiers;
 128   CPP_OPTION (pfile, std)                        = l->std;
 129   CPP_OPTION (pfile, digraphs)                   = l->digraphs;
 130   CPP_OPTION (pfile, uliterals)                  = l->uliterals;
 131   CPP_OPTION (pfile, rliterals)                  = l->rliterals;
 132   CPP_OPTION (pfile, user_literals)              = l->user_literals;
 133   CPP_OPTION (pfile, binary_constants)           = l->binary_constants;
 134   CPP_OPTION (pfile, digit_separators)           = l->digit_separators;
 135   CPP_OPTION (pfile, trigraphs)                  = l->trigraphs;
 136 }
 137
 138 /* Initialize library global state.  */
 139 static void
 140 init_library (void)
 141 {
 142   static int initialized = 0;
 143
 144   if (! initialized)
 145     {
 146       initialized = 1;
 147
 148       _cpp_init_lexer ();
 149
 150       /* Set up the trigraph map.  This doesn't need to do anything if
 151          we were compiled with a compiler that supports C99 designated
 152          initializers.  */
 153       init_trigraph_map ();
 154
 155 #ifdef ENABLE_NLS
 156        (void) bindtextdomain (PACKAGE, LOCALEDIR);
 157 #endif
 158     }
 159 }
 160
 161 /* Initialize a cpp_reader structure.  */
 162 cpp_reader *
 163 cpp_create_reader (enum c_lang lang, cpp_hash_table *table,
 164                    struct line_maps *line_table)
 165 {
 166   cpp_reader *pfile;
 167
 168   /* Initialize this instance of the library if it hasn't been already.  */
 169   init_library ();
 170
 171   pfile = XCNEW (cpp_reader);
 172   memset (&pfile->base_context, 0, sizeof (pfile->base_context));
 173
 174   cpp_set_lang (pfile, lang);
 175   CPP_OPTION (pfile, warn_multichar) = 1;
 176   CPP_OPTION (pfile, discard_comments) = 1;
 177   CPP_OPTION (pfile, discard_comments_in_macro_exp) = 1;
 178   CPP_OPTION (pfile, tabstop) = 8;
 179   CPP_OPTION (pfile, operator_names) = 1;
 180   CPP_OPTION (pfile, warn_trigraphs) = 2;
 181   CPP_OPTION (pfile, warn_endif_labels) = 1;
 182   CPP_OPTION (pfile, cpp_warn_c90_c99_compat) = -1;
 183   CPP_OPTION (pfile, cpp_warn_deprecated) = 1;
 184   CPP_OPTION (pfile, cpp_warn_long_long) = 0;
 185   CPP_OPTION (pfile, dollars_in_ident) = 1;
 186   CPP_OPTION (pfile, warn_dollars) = 1;
 187   CPP_OPTION (pfile, warn_variadic_macros) = 1;
 188   CPP_OPTION (pfile, warn_builtin_macro_redefined) = 1;
 189   /* By default, track locations of tokens resulting from macro
 190      expansion.  The '2' means, track the locations with the highest
 191      accuracy.  Read the comments for struct
 192      cpp_options::track_macro_expansion to learn about the other
 193      values.  */
 194   CPP_OPTION (pfile, track_macro_expansion) = 2;
 195   CPP_OPTION (pfile, warn_normalize) = normalized_C;
 196   CPP_OPTION (pfile, warn_literal_suffix) = 1;
 197   CPP_OPTION (pfile, canonical_system_headers)
 198       = ENABLE_CANONICAL_SYSTEM_HEADERS;
 199   CPP_OPTION (pfile, ext_numeric_literals) = 1;
 200   CPP_OPTION (pfile, warn_date_time) = 0;
 201
 202   /* Default CPP arithmetic to something sensible for the host for the
 203      benefit of dumb users like fix-header.  */
 204   CPP_OPTION (pfile, precision) = CHAR_BIT * sizeof (long);
 205   CPP_OPTION (pfile, char_precision) = CHAR_BIT;
 206   CPP_OPTION (pfile, wchar_precision) = CHAR_BIT * sizeof (int);
 207   CPP_OPTION (pfile, int_precision) = CHAR_BIT * sizeof (int);
 208   CPP_OPTION (pfile, unsigned_char) = 0;
 209   CPP_OPTION (pfile, unsigned_wchar) = 1;
 210   CPP_OPTION (pfile, bytes_big_endian) = 1;  /* does not matter */
 211
 212   /* Default to no charset conversion.  */
 213   CPP_OPTION (pfile, narrow_charset) = _cpp_default_encoding ();
 214   CPP_OPTION (pfile, wide_charset) = 0;
 215
 216   /* Default the input character set to UTF-8.  */
 217   CPP_OPTION (pfile, input_charset) = _cpp_default_encoding ();
 218
 219   /* A fake empty "directory" used as the starting point for files
 220      looked up without a search path.  Name cannot be '/' because we
 221      don't want to prepend anything at all to filenames using it.  All
 222      other entries are correct zero-initialized.  */
 223   pfile->no_search_path.name = (char *) "";
 224
 225   /* Initialize the line map.  */
 226   pfile->line_table = line_table;
 227
 228   /* Initialize lexer state.  */
 229   pfile->state.save_comments = ! CPP_OPTION (pfile, discard_comments);
 230
 231   /* Set up static tokens.  */
 232   pfile->avoid_paste.type = CPP_PADDING;
 233   pfile->avoid_paste.val.source = NULL;
 234   pfile->eof.type = CPP_EOF;
 235   pfile->eof.flags = 0;
 236
 237   /* Create a token buffer for the lexer.  */
 238   _cpp_init_tokenrun (&pfile->base_run, 250);
 239   pfile->cur_run = &pfile->base_run;
 240   pfile->cur_token = pfile->base_run.base;
 241
 242   /* Initialize the base context.  */
 243   pfile->context = &pfile->base_context;
 244   pfile->base_context.c.macro = 0;
 245   pfile->base_context.prev = pfile->base_context.next = 0;
 246
 247   /* Aligned and unaligned storage.  */
 248   pfile->a_buff = _cpp_get_buff (pfile, 0);
 249   pfile->u_buff = _cpp_get_buff (pfile, 0);
 250
 251   /* Initialize table for push_macro/pop_macro.  */
 252   pfile->pushed_macros = 0;
 253
 254   /* Do not force token locations by default.  */
 255   pfile->forced_token_location_p = NULL;
 256
 257   /* The expression parser stack.  */
 258   _cpp_expand_op_stack (pfile);
 259
 260   /* Initialize the buffer obstack.  */
 261   obstack_specify_allocation (&pfile->buffer_ob, 0, 0, xmalloc, free);
 262
 263   _cpp_init_files (pfile);
 264
 265   _cpp_init_hashtable (pfile, table);
 266
 267   return pfile;
 268 }
 269
 270 /* Set the line_table entry in PFILE.  This is called after reading a
 271    PCH file, as the old line_table will be incorrect.  */
 272 void
 273 cpp_set_line_map (cpp_reader *pfile, struct line_maps *line_table)
 274 {
 275   pfile->line_table = line_table;
 276 }
 277
 278 /* Free resources used by PFILE.  Accessing PFILE after this function
 279    returns leads to undefined behavior.  Returns the error count.  */
 280 void
 281 cpp_destroy (cpp_reader *pfile)
 282 {
 283   cpp_context *context, *contextn;
 284   struct def_pragma_macro *pmacro;
 285   tokenrun *run, *runn;
 286   int i;
 287
 288   free (pfile->op_stack);
 289
 290   while (CPP_BUFFER (pfile) != NULL)
 291     _cpp_pop_buffer (pfile);
 292
 293   free (pfile->out.base);
 294
 295   if (pfile->macro_buffer)
 296     {
 297       free (pfile->macro_buffer);
 298       pfile->macro_buffer = NULL;
 299       pfile->macro_buffer_len = 0;
 300     }
 301
 302   if (pfile->deps)
 303     deps_free (pfile->deps);
 304   obstack_free (&pfile->buffer_ob, 0);
 305
 306   _cpp_destroy_hashtable (pfile);
 307   _cpp_cleanup_files (pfile);
 308   _cpp_destroy_iconv (pfile);
 309
 310   _cpp_free_buff (pfile->a_buff);
 311   _cpp_free_buff (pfile->u_buff);
 312   _cpp_free_buff (pfile->free_buffs);
 313
 314   for (run = &pfile->base_run; run; run = runn)
 315     {
 316       runn = run->next;
 317       free (run->base);
 318       if (run != &pfile->base_run)
 319         free (run);
 320     }
 321
 322   for (context = pfile->base_context.next; context; context = contextn)
 323     {
 324       contextn = context->next;
 325       free (context);
 326     }
 327
 328   if (pfile->comments.entries)
 329     {
 330       for (i = 0; i < pfile->comments.count; i++)
 331         free (pfile->comments.entries[i].comment);
 332
 333       free (pfile->comments.entries);
 334     }
 335   if (pfile->pushed_macros)
 336     {
 337       do
 338         {
 339           pmacro = pfile->pushed_macros;
 340           pfile->pushed_macros = pmacro->next;
 341           free (pmacro->name);
 342           free (pmacro);
 343         }
 344       while (pfile->pushed_macros);
 345     }
 346
 347   free (pfile);
 348 }
 349
 350 /* This structure defines one built-in identifier.  A node will be
 351    entered in the hash table under the name NAME, with value VALUE.
 352
 353    There are two tables of these.  builtin_array holds all the
 354    "builtin" macros: these are handled by builtin_macro() in
 355    macro.c.  Builtin is somewhat of a misnomer -- the property of
 356    interest is that these macros require special code to compute their
 357    expansions.  The value is a "cpp_builtin_type" enumerator.
 358
 359    operator_array holds the C++ named operators.  These are keywords
 360    which act as aliases for punctuators.  In C++, they cannot be
 361    altered through #define, and #if recognizes them as operators.  In
 362    C, these are not entered into the hash table at all (but see
 363    <iso646.h>).  The value is a token-type enumerator.  */
 364 struct builtin_macro
 365 {
 366   const uchar *const name;
 367   const unsigned short len;
 368   const unsigned short value;
 369   const bool always_warn_if_redefined;
 370 };
 371
 372 #define B(n, t, f)    { DSC(n), t, f }
 373 static const struct builtin_macro builtin_array[] =
 374 {
 375   B("__TIMESTAMP__",     BT_TIMESTAMP,     false),
 376   B("__TIME__",          BT_TIME,          false),
 377   B("__DATE__",          BT_DATE,          false),
 378   B("__FILE__",          BT_FILE,          false),
 379   B("__BASE_FILE__",     BT_BASE_FILE,     false),
 380   B("__LINE__",          BT_SPECLINE,      true),
 381   B("__INCLUDE_LEVEL__", BT_INCLUDE_LEVEL, true),
 382   B("__COUNTER__",       BT_COUNTER,       true),
 383   B("__has_attribute",   BT_HAS_ATTRIBUTE, true),
 384   B("__has_cpp_attribute", BT_HAS_ATTRIBUTE, true),
 385   /* Keep builtins not used for -traditional-cpp at the end, and
 386      update init_builtins() if any more are added.  */
 387   B("_Pragma",           BT_PRAGMA,        true),
 388   B("__STDC__",          BT_STDC,          true),
 389 };
 390 #undef B
 391
 392 struct builtin_operator
 393 {
 394   const uchar *const name;
 395   const unsigned short len;
 396   const unsigned short value;
 397 };
 398
 399 #define B(n, t)    { DSC(n), t }
 400 static const struct builtin_operator operator_array[] =
 401 {
 402   B("and",      CPP_AND_AND),
 403   B("and_eq",   CPP_AND_EQ),
 404   B("bitand",   CPP_AND),
 405   B("bitor",    CPP_OR),
 406   B("compl",    CPP_COMPL),
 407   B("not",      CPP_NOT),
 408   B("not_eq",   CPP_NOT_EQ),
 409   B("or",       CPP_OR_OR),
 410   B("or_eq",    CPP_OR_EQ),
 411   B("xor",      CPP_XOR),
 412   B("xor_eq",   CPP_XOR_EQ)
 413 };
 414 #undef B
 415
 416 /* Mark the C++ named operators in the hash table.  */
 417 static void
 418 mark_named_operators (cpp_reader *pfile, int flags)
 419 {
 420   const struct builtin_operator *b;
 421
 422   for (b = operator_array;
 423        b < (operator_array + ARRAY_SIZE (operator_array));
 424        b++)
 425     {
 426       cpp_hashnode *hp = cpp_lookup (pfile, b->name, b->len);
 427       hp->flags |= flags;
 428       hp->is_directive = 0;
 429       hp->directive_index = b->value;
 430     }
 431 }
 432
 433 /* Helper function of cpp_type2name. Return the string associated with
 434    named operator TYPE.  */
 435 const char *
 436 cpp_named_operator2name (enum cpp_ttype type)
 437 {
 438   const struct builtin_operator *b;
 439
 440   for (b = operator_array;
 441        b < (operator_array + ARRAY_SIZE (operator_array));
 442        b++)
 443     {
 444       if (type == b->value)
 445         return (const char *) b->name;
 446     }
 447
 448   return NULL;
 449 }
 450
 451 void
 452 cpp_init_special_builtins (cpp_reader *pfile)
 453 {
 454   const struct builtin_macro *b;
 455   size_t n = ARRAY_SIZE (builtin_array);
 456
 457   if (CPP_OPTION (pfile, traditional))
 458     n -= 2;
 459   else if (! CPP_OPTION (pfile, stdc_0_in_system_headers)
 460            || CPP_OPTION (pfile, std))
 461     n--;
 462
 463   for (b = builtin_array; b < builtin_array + n; b++)
 464     {
 465       if (b->value == BT_HAS_ATTRIBUTE
 466           && (CPP_OPTION (pfile, lang) == CLK_ASM
 467               || pfile->cb.has_attribute == NULL))
 468         continue;
 469       cpp_hashnode *hp = cpp_lookup (pfile, b->name, b->len);
 470       hp->type = NT_MACRO;
 471       hp->flags |= NODE_BUILTIN;
 472       if (b->always_warn_if_redefined)
 473         hp->flags |= NODE_WARN;
 474       hp->value.builtin = (enum cpp_builtin_type) b->value;
 475     }
 476 }
 477
 478 /* Read the builtins table above and enter them, and language-specific
 479    macros, into the hash table.  HOSTED is true if this is a hosted
 480    environment.  */
 481 void
 482 cpp_init_builtins (cpp_reader *pfile, int hosted)
 483 {
 484   cpp_init_special_builtins (pfile);
 485
 486   if (!CPP_OPTION (pfile, traditional)
 487       && (! CPP_OPTION (pfile, stdc_0_in_system_headers)
 488           || CPP_OPTION (pfile, std)))
 489     _cpp_define_builtin (pfile, "__STDC__ 1");
 490
 491   if (CPP_OPTION (pfile, cplusplus))
 492     {
 493       if (CPP_OPTION (pfile, lang) == CLK_CXX1Z
 494           || CPP_OPTION (pfile, lang) == CLK_GNUCXX1Z)
 495         _cpp_define_builtin (pfile, "__cplusplus 201500L");
 496       else if (CPP_OPTION (pfile, lang) == CLK_CXX14
 497           || CPP_OPTION (pfile, lang) == CLK_GNUCXX14)
 498         _cpp_define_builtin (pfile, "__cplusplus 201402L");
 499       else if (CPP_OPTION (pfile, lang) == CLK_CXX11
 500                || CPP_OPTION (pfile, lang) == CLK_GNUCXX11)
 501         _cpp_define_builtin (pfile, "__cplusplus 201103L");
 502       else
 503         _cpp_define_builtin (pfile, "__cplusplus 199711L");
 504     }
 505   else if (CPP_OPTION (pfile, lang) == CLK_ASM)
 506     _cpp_define_builtin (pfile, "__ASSEMBLER__ 1");
 507   else if (CPP_OPTION (pfile, lang) == CLK_STDC94)
 508     _cpp_define_builtin (pfile, "__STDC_VERSION__ 199409L");
 509   else if (CPP_OPTION (pfile, lang) == CLK_STDC11
 510            || CPP_OPTION (pfile, lang) == CLK_GNUC11)
 511     _cpp_define_builtin (pfile, "__STDC_VERSION__ 201112L");
 512   else if (CPP_OPTION (pfile, c99))
 513     _cpp_define_builtin (pfile, "__STDC_VERSION__ 199901L");
 514
 515   if (CPP_OPTION (pfile, uliterals)
 516       && !(CPP_OPTION (pfile, cplusplus)
 517            && (CPP_OPTION (pfile, lang) == CLK_GNUCXX
 518             || CPP_OPTION (pfile, lang) == CLK_CXX98)))
 519     {
 520       _cpp_define_builtin (pfile, "__STDC_UTF_16__ 1");
 521       _cpp_define_builtin (pfile, "__STDC_UTF_32__ 1");
 522     }
 523
 524   if (hosted)
 525     _cpp_define_builtin (pfile, "__STDC_HOSTED__ 1");
 526   else
 527     _cpp_define_builtin (pfile, "__STDC_HOSTED__ 0");
 528
 529   if (CPP_OPTION (pfile, objc))
 530     _cpp_define_builtin (pfile, "__OBJC__ 1");
 531 }
 532
 533 /* Sanity-checks are dependent on command-line options, so it is
 534    called as a subroutine of cpp_read_main_file ().  */
 535 #if ENABLE_CHECKING
 536 static void sanity_checks (cpp_reader *);
 537 static void sanity_checks (cpp_reader *pfile)
 538 {
 539   cppchar_t test = 0;
 540   size_t max_precision = 2 * CHAR_BIT * sizeof (cpp_num_part);
 541
 542   /* Sanity checks for assumptions about CPP arithmetic and target
 543      type precisions made by cpplib.  */
 544   test--;
 545   if (test < 1)
 546     cpp_error (pfile, CPP_DL_ICE, "cppchar_t must be an unsigned type");
 547
 548   if (CPP_OPTION (pfile, precision) > max_precision)
 549     cpp_error (pfile, CPP_DL_ICE,
 550                "preprocessor arithmetic has maximum precision of %lu bits;"
 551                " target requires %lu bits",
 552                (unsigned long) max_precision,
 553                (unsigned long) CPP_OPTION (pfile, precision));
 554
 555   if (CPP_OPTION (pfile, precision) < CPP_OPTION (pfile, int_precision))
 556     cpp_error (pfile, CPP_DL_ICE,
 557                "CPP arithmetic must be at least as precise as a target int");
 558
 559   if (CPP_OPTION (pfile, char_precision) < 8)
 560     cpp_error (pfile, CPP_DL_ICE, "target char is less than 8 bits wide");
 561
 562   if (CPP_OPTION (pfile, wchar_precision) < CPP_OPTION (pfile, char_precision))
 563     cpp_error (pfile, CPP_DL_ICE,
 564                "target wchar_t is narrower than target char");
 565
 566   if (CPP_OPTION (pfile, int_precision) < CPP_OPTION (pfile, char_precision))
 567     cpp_error (pfile, CPP_DL_ICE,
 568                "target int is narrower than target char");
 569
 570   /* This is assumed in eval_token() and could be fixed if necessary.  */
 571   if (sizeof (cppchar_t) > sizeof (cpp_num_part))
 572     cpp_error (pfile, CPP_DL_ICE,
 573                "CPP half-integer narrower than CPP character");
 574
 575   if (CPP_OPTION (pfile, wchar_precision) > BITS_PER_CPPCHAR_T)
 576     cpp_error (pfile, CPP_DL_ICE,
 577                "CPP on this host cannot handle wide character constants over"
 578                " %lu bits, but the target requires %lu bits",
 579                (unsigned long) BITS_PER_CPPCHAR_T,
 580                (unsigned long) CPP_OPTION (pfile, wchar_precision));
 581 }
 582 #else
 583 # define sanity_checks(PFILE)
 584 #endif
 585
 586 /* This is called after options have been parsed, and partially
 587    processed.  */
 588 void
 589 cpp_post_options (cpp_reader *pfile)
 590 {
 591   int flags;
 592
 593   sanity_checks (pfile);
 594
 595   post_options (pfile);
 596
 597   /* Mark named operators before handling command line macros.  */
 598   flags = 0;
 599   if (CPP_OPTION (pfile, cplusplus) && CPP_OPTION (pfile, operator_names))
 600     flags |= NODE_OPERATOR;
 601   if (CPP_OPTION (pfile, warn_cxx_operator_names))
 602     flags |= NODE_DIAGNOSTIC | NODE_WARN_OPERATOR;
 603   if (flags != 0)
 604     mark_named_operators (pfile, flags);
 605 }
 606
 607 /* Setup for processing input from the file named FNAME, or stdin if
 608    it is the empty string.  Return the original filename
 609    on success (e.g. foo.i->foo.c), or NULL on failure.  */
 610 const char *
 611 cpp_read_main_file (cpp_reader *pfile, const char *fname)
 612 {
 613   if (CPP_OPTION (pfile, deps.style) != DEPS_NONE)
 614     {
 615       if (!pfile->deps)
 616         pfile->deps = deps_init ();
 617
 618       /* Set the default target (if there is none already).  */
 619       deps_add_default_target (pfile->deps, fname);
 620     }
 621
 622   pfile->main_file
 623     = _cpp_find_file (pfile, fname, &pfile->no_search_path, false, 0, false);
 624   if (_cpp_find_failed (pfile->main_file))
 625     return NULL;
 626
 627   _cpp_stack_file (pfile, pfile->main_file, false);
 628
 629   /* For foo.i, read the original filename foo.c now, for the benefit
 630      of the front ends.  */
 631   if (CPP_OPTION (pfile, preprocessed))
 632     {
 633       read_original_filename (pfile);
 634       fname =
 635         ORDINARY_MAP_FILE_NAME
 636         ((LINEMAPS_LAST_ORDINARY_MAP (pfile->line_table)));
 637     }
 638   return fname;
 639 }
 640
 641 /* For preprocessed files, if the first tokens are of the form # NUM.
 642    handle the directive so we know the original file name.  This will
 643    generate file_change callbacks, which the front ends must handle
 644    appropriately given their state of initialization.  */
 645 static void
 646 read_original_filename (cpp_reader *pfile)
 647 {
 648   const cpp_token *token, *token1;
 649
 650   /* Lex ahead; if the first tokens are of the form # NUM, then
 651      process the directive, otherwise back up.  */
 652   token = _cpp_lex_direct (pfile);
 653   if (token->type == CPP_HASH)
 654     {
 655       pfile->state.in_directive = 1;
 656       token1 = _cpp_lex_direct (pfile);
 657       _cpp_backup_tokens (pfile, 1);
 658       pfile->state.in_directive = 0;
 659
 660       /* If it's a #line directive, handle it.  */
 661       if (token1->type == CPP_NUMBER
 662           && _cpp_handle_directive (pfile, token->flags & PREV_WHITE))
 663         {
 664           read_original_directory (pfile);
 665           return;
 666         }
 667     }
 668
 669   /* Backup as if nothing happened.  */
 670   _cpp_backup_tokens (pfile, 1);
 671 }
 672
 673 /* For preprocessed files, if the tokens following the first filename
 674    line is of the form # <line> "/path/name//", handle the
 675    directive so we know the original current directory.  */
 676 static void
 677 read_original_directory (cpp_reader *pfile)
 678 {
 679   const cpp_token *hash, *token;
 680
 681   /* Lex ahead; if the first tokens are of the form # NUM, then
 682      process the directive, otherwise back up.  */
 683   hash = _cpp_lex_direct (pfile);
 684   if (hash->type != CPP_HASH)
 685     {
 686       _cpp_backup_tokens (pfile, 1);
 687       return;
 688     }
 689
 690   token = _cpp_lex_direct (pfile);
 691
 692   if (token->type != CPP_NUMBER)
 693     {
 694       _cpp_backup_tokens (pfile, 2);
 695       return;
 696     }
 697
 698   token = _cpp_lex_direct (pfile);
 699
 700   if (token->type != CPP_STRING
 701       || ! (token->val.str.len >= 5
 702             && IS_DIR_SEPARATOR (token->val.str.text[token->val.str.len-2])
 703             && IS_DIR_SEPARATOR (token->val.str.text[token->val.str.len-3])))
 704     {
 705       _cpp_backup_tokens (pfile, 3);
 706       return;
 707     }
 708
 709   if (pfile->cb.dir_change)
 710     {
 711       char *debugdir = (char *) alloca (token->val.str.len - 3);
 712
 713       memcpy (debugdir, (const char *) token->val.str.text + 1,
 714               token->val.str.len - 4);
 715       debugdir[token->val.str.len - 4] = '\0';
 716
 717       pfile->cb.dir_change (pfile, debugdir);
 718     }
 719 }
 720
 721 /* This is called at the end of preprocessing.  It pops the last
 722    buffer and writes dependency output.
 723
 724    Maybe it should also reset state, such that you could call
 725    cpp_start_read with a new filename to restart processing.  */
 726 void
 727 cpp_finish (cpp_reader *pfile, FILE *deps_stream)
 728 {
 729   /* Warn about unused macros before popping the final buffer.  */
 730   if (CPP_OPTION (pfile, warn_unused_macros))
 731     cpp_forall_identifiers (pfile, _cpp_warn_if_unused_macro, NULL);
 732
 733   /* lex.c leaves the final buffer on the stack.  This it so that
 734      it returns an unending stream of CPP_EOFs to the client.  If we
 735      popped the buffer, we'd dereference a NULL buffer pointer and
 736      segfault.  It's nice to allow the client to do worry-free excess
 737      cpp_get_token calls.  */
 738   while (pfile->buffer)
 739     _cpp_pop_buffer (pfile);
 740
 741   if (CPP_OPTION (pfile, deps.style) != DEPS_NONE
 742       && deps_stream)
 743     {
 744       deps_write (pfile->deps, deps_stream, 72);
 745
 746       if (CPP_OPTION (pfile, deps.phony_targets))
 747         deps_phony_targets (pfile->deps, deps_stream);
 748     }
 749
 750   /* Report on headers that could use multiple include guards.  */
 751   if (CPP_OPTION (pfile, print_include_names))
 752     _cpp_report_missing_guards (pfile);
 753 }
 754
 755 static void
 756 post_options (cpp_reader *pfile)
 757 {
 758   /* -Wtraditional is not useful in C++ mode.  */
 759   if (CPP_OPTION (pfile, cplusplus))
 760     CPP_OPTION (pfile, cpp_warn_traditional) = 0;
 761
 762   /* Permanently disable macro expansion if we are rescanning
 763      preprocessed text.  Read preprocesed source in ISO mode.  */
 764   if (CPP_OPTION (pfile, preprocessed))
 765     {
 766       if (!CPP_OPTION (pfile, directives_only))
 767         pfile->state.prevent_expansion = 1;
 768       CPP_OPTION (pfile, traditional) = 0;
 769     }
 770
 771   if (CPP_OPTION (pfile, warn_trigraphs) == 2)
 772     CPP_OPTION (pfile, warn_trigraphs) = !CPP_OPTION (pfile, trigraphs);
 773
 774   if (CPP_OPTION (pfile, traditional))
 775     {
 776       CPP_OPTION (pfile, trigraphs) = 0;
 777       CPP_OPTION (pfile, warn_trigraphs) = 0;
 778     }
 779 }