libcpp/directives.c

   1 /* CPP Library. (Directive handling.)
   2    Copyright (C) 1986, 1987, 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
   3    1999, 2000, 2001, 2002, 2003, 2004, 2005,
   4    2007 Free Software Foundation, Inc.
   5    Contributed by Per Bothner, 1994-95.
   6    Based on CCCP program by Paul Rubin, June 1986
   7    Adapted to ANSI C, Richard Stallman, Jan 1987
   8
   9 This program is free software; you can redistribute it and/or modify it
  10 under the terms of the GNU General Public License as published by the
  11 Free Software Foundation; either version 2, or (at your option) any
  12 later version.
  13
  14 This program is distributed in the hope that it will be useful,
  15 but WITHOUT ANY WARRANTY; without even the implied warranty of
  16 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17 GNU General Public License for more details.
  18
  19 You should have received a copy of the GNU General Public License
  20 along with this program; if not, write to the Free Software
  21 Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */
  22
  23 #include "config.h"
  24 #include "system.h"
  25 #include "cpplib.h"
  26 #include "internal.h"
  27 #include "mkdeps.h"
  28 #include "obstack.h"
  29
  30 /* Stack of conditionals currently in progress
  31    (including both successful and failing conditionals).  */
  32 struct if_stack
  33 {
  34   struct if_stack *next;
  35   unsigned int line;            /* Line where condition started.  */
  36   const cpp_hashnode *mi_cmacro;/* macro name for #ifndef around entire file */
  37   bool skip_elses;              /* Can future #else / #elif be skipped?  */
  38   bool was_skipping;            /* If were skipping on entry.  */
  39   int type;                     /* Most recent conditional for diagnostics.  */
  40 };
  41
  42 /* Contains a registered pragma or pragma namespace.  */
  43 typedef void (*pragma_cb) (cpp_reader *);
  44 struct pragma_entry
  45 {
  46   struct pragma_entry *next;
  47   const cpp_hashnode *pragma;   /* Name and length.  */
  48   bool is_nspace;
  49   bool is_internal;
  50   bool is_deferred;
  51   bool allow_expansion;
  52   union {
  53     pragma_cb handler;
  54     struct pragma_entry *space;
  55     unsigned int ident;
  56   } u;
  57 };
  58
  59 /* Values for the origin field of struct directive.  KANDR directives
  60    come from traditional (K&R) C.  STDC89 directives come from the
  61    1989 C standard.  EXTENSION directives are extensions.  */
  62 #define KANDR           0
  63 #define STDC89          1
  64 #define EXTENSION       2
  65
  66 /* Values for the flags field of struct directive.  COND indicates a
  67    conditional; IF_COND an opening conditional.  INCL means to treat
  68    "..." and <...> as q-char and h-char sequences respectively.  IN_I
  69    means this directive should be handled even if -fpreprocessed is in
  70    effect (these are the directives with callback hooks).
  71
  72    EXPAND is set on directives that are always macro-expanded.  */
  73 #define COND            (1 << 0)
  74 #define IF_COND         (1 << 1)
  75 #define INCL            (1 << 2)
  76 #define IN_I            (1 << 3)
  77 #define EXPAND          (1 << 4)
  78
  79 /* Defines one #-directive, including how to handle it.  */
  80 typedef void (*directive_handler) (cpp_reader *);
  81 typedef struct directive directive;
  82 struct directive
  83 {
  84   directive_handler handler;    /* Function to handle directive.  */
  85   const uchar *name;            /* Name of directive.  */
  86   unsigned short length;        /* Length of name.  */
  87   unsigned char origin;         /* Origin of directive.  */
  88   unsigned char flags;          /* Flags describing this directive.  */
  89 };
  90
  91 /* Forward declarations.  */
  92
  93 static void skip_rest_of_line (cpp_reader *);
  94 static void check_eol (cpp_reader *);
  95 static void start_directive (cpp_reader *);
  96 static void prepare_directive_trad (cpp_reader *);
  97 static void end_directive (cpp_reader *, int);
  98 static void directive_diagnostics (cpp_reader *, const directive *, int);
  99 static void run_directive (cpp_reader *, int, const char *, size_t);
 100 static char *glue_header_name (cpp_reader *);
 101 static const char *parse_include (cpp_reader *, int *, const cpp_token ***);
 102 static void push_conditional (cpp_reader *, int, int, const cpp_hashnode *);
 103 static unsigned int read_flag (cpp_reader *, unsigned int);
 104 static int strtoul_for_line (const uchar *, unsigned int, unsigned long *);
 105 static void do_diagnostic (cpp_reader *, int, int);
 106 static cpp_hashnode *lex_macro_node (cpp_reader *, bool);
 107 static int undefine_macros (cpp_reader *, cpp_hashnode *, void *);
 108 static void do_include_common (cpp_reader *, enum include_type);
 109 static struct pragma_entry *lookup_pragma_entry (struct pragma_entry *,
 110                                                  const cpp_hashnode *);
 111 static int count_registered_pragmas (struct pragma_entry *);
 112 static char ** save_registered_pragmas (struct pragma_entry *, char **);
 113 static char ** restore_registered_pragmas (cpp_reader *, struct pragma_entry *,
 114                                            char **);
 115 static void do_pragma_once (cpp_reader *);
 116 static void do_pragma_poison (cpp_reader *);
 117 static void do_pragma_system_header (cpp_reader *);
 118 static void do_pragma_dependency (cpp_reader *);
 119 static void do_linemarker (cpp_reader *);
 120 static const cpp_token *get_token_no_padding (cpp_reader *);
 121 static const cpp_token *get__Pragma_string (cpp_reader *);
 122 static void destringize_and_run (cpp_reader *, const cpp_string *);
 123 static int parse_answer (cpp_reader *, struct answer **, int);
 124 static cpp_hashnode *parse_assertion (cpp_reader *, struct answer **, int);
 125 static struct answer ** find_answer (cpp_hashnode *, const struct answer *);
 126 static void handle_assertion (cpp_reader *, const char *, int);
 127
 128 /* This is the table of directive handlers.  It is ordered by
 129    frequency of occurrence; the numbers at the end are directive
 130    counts from all the source code I have lying around (egcs and libc
 131    CVS as of 1999-05-18, plus grub-0.5.91, linux-2.2.9, and
 132    pcmcia-cs-3.0.9).  This is no longer important as directive lookup
 133    is now O(1).  All extensions other than #warning and #include_next
 134    are deprecated.  The name is where the extension appears to have
 135    come from.  */
 136
 137 #define DIRECTIVE_TABLE                                                 \
 138 D(define,       T_DEFINE = 0,   KANDR,     IN_I)           /* 270554 */ \
 139 D(include,      T_INCLUDE,      KANDR,     INCL | EXPAND)  /*  52262 */ \
 140 D(endif,        T_ENDIF,        KANDR,     COND)           /*  45855 */ \
 141 D(ifdef,        T_IFDEF,        KANDR,     COND | IF_COND) /*  22000 */ \
 142 D(if,           T_IF,           KANDR, COND | IF_COND | EXPAND) /*  18162 */ \
 143 D(else,         T_ELSE,         KANDR,     COND)           /*   9863 */ \
 144 D(ifndef,       T_IFNDEF,       KANDR,     COND | IF_COND) /*   9675 */ \
 145 D(undef,        T_UNDEF,        KANDR,     IN_I)           /*   4837 */ \
 146 D(line,         T_LINE,         KANDR,     EXPAND)         /*   2465 */ \
 147 D(elif,         T_ELIF,         STDC89,    COND | EXPAND)  /*    610 */ \
 148 D(error,        T_ERROR,        STDC89,    0)              /*    475 */ \
 149 D(pragma,       T_PRAGMA,       STDC89,    IN_I)           /*    195 */ \
 150 D(warning,      T_WARNING,      EXTENSION, 0)              /*     22 */ \
 151 D(include_next, T_INCLUDE_NEXT, EXTENSION, INCL | EXPAND)  /*     19 */ \
 152 D(ident,        T_IDENT,        EXTENSION, IN_I)           /*     11 */ \
 153 D(import,       T_IMPORT,       EXTENSION, INCL | EXPAND)  /* 0 ObjC */ \
 154 D(assert,       T_ASSERT,       EXTENSION, 0)              /* 0 SVR4 */ \
 155 D(unassert,     T_UNASSERT,     EXTENSION, 0)              /* 0 SVR4 */ \
 156 D(sccs,         T_SCCS,         EXTENSION, IN_I)           /* 0 SVR4? */
 157
 158 /* #sccs is synonymous with #ident.  */
 159 #define do_sccs do_ident
 160
 161 /* Use the table to generate a series of prototypes, an enum for the
 162    directive names, and an array of directive handlers.  */
 163
 164 #define D(name, t, o, f) static void do_##name (cpp_reader *);
 165 DIRECTIVE_TABLE
 166 #undef D
 167
 168 #define D(n, tag, o, f) tag,
 169 enum
 170 {
 171   DIRECTIVE_TABLE
 172   N_DIRECTIVES
 173 };
 174 #undef D
 175
 176 #define D(name, t, origin, flags) \
 177 { do_##name, (const uchar *) #name, \
 178   sizeof #name - 1, origin, flags },
 179 static const directive dtable[] =
 180 {
 181 DIRECTIVE_TABLE
 182 };
 183 #undef D
 184 #undef DIRECTIVE_TABLE
 185
 186 /* Wrapper struct directive for linemarkers.
 187    The origin is more or less true - the original K+R cpp
 188    did use this notation in its preprocessed output.  */
 189 static const directive linemarker_dir =
 190 {
 191   do_linemarker, U"#", 1, KANDR, IN_I
 192 };
 193
 194 #define SEEN_EOL() (pfile->cur_token[-1].type == CPP_EOF)
 195
 196 /* Skip any remaining tokens in a directive.  */
 197 static void
 198 skip_rest_of_line (cpp_reader *pfile)
 199 {
 200   /* Discard all stacked contexts.  */
 201   while (pfile->context->prev)
 202     _cpp_pop_context (pfile);
 203
 204   /* Sweep up all tokens remaining on the line.  */
 205   if (! SEEN_EOL ())
 206     while (_cpp_lex_token (pfile)->type != CPP_EOF)
 207       ;
 208 }
 209
 210 /* Ensure there are no stray tokens at the end of a directive.  */
 211 static void
 212 check_eol (cpp_reader *pfile)
 213 {
 214   if (! SEEN_EOL () && _cpp_lex_token (pfile)->type != CPP_EOF)
 215     cpp_error (pfile, CPP_DL_PEDWARN, "extra tokens at end of #%s directive",
 216                pfile->directive->name);
 217 }
 218
 219 /* Ensure there are no stray tokens other than comments at the end of
 220    a directive, and gather the comments.  */
 221 static const cpp_token **
 222 check_eol_return_comments (cpp_reader *pfile)
 223 {
 224   size_t c;
 225   size_t capacity = 8;
 226   const cpp_token **buf;
 227
 228   buf = XNEWVEC (const cpp_token *, capacity);
 229   c = 0;
 230   if (! SEEN_EOL ())
 231     {
 232       while (1)
 233         {
 234           const cpp_token *tok;
 235
 236           tok = _cpp_lex_token (pfile);
 237           if (tok->type == CPP_EOF)
 238             break;
 239           if (tok->type != CPP_COMMENT)
 240             cpp_error (pfile, CPP_DL_PEDWARN,
 241                        "extra tokens at end of #%s directive",
 242                        pfile->directive->name);
 243           else
 244             {
 245               if (c + 1 >= capacity)
 246                 {
 247                   capacity *= 2;
 248                   buf = XRESIZEVEC (const cpp_token *, buf, capacity);
 249                 }
 250               buf[c] = tok;
 251               ++c;
 252             }
 253         }
 254     }
 255   buf[c] = NULL;
 256   return buf;
 257 }
 258
 259 /* Called when entering a directive, _Pragma or command-line directive.  */
 260 static void
 261 start_directive (cpp_reader *pfile)
 262 {
 263   /* Setup in-directive state.  */
 264   pfile->state.in_directive = 1;
 265   pfile->state.save_comments = 0;
 266   pfile->directive_result.type = CPP_PADDING;
 267
 268   /* Some handlers need the position of the # for diagnostics.  */
 269   pfile->directive_line = pfile->line_table->highest_line;
 270 }
 271
 272 /* Called when leaving a directive, _Pragma or command-line directive.  */
 273 static void
 274 end_directive (cpp_reader *pfile, int skip_line)
 275 {
 276   if (pfile->state.in_deferred_pragma)
 277     ;
 278   else if (CPP_OPTION (pfile, traditional))
 279     {
 280       /* Revert change of prepare_directive_trad.  */
 281       pfile->state.prevent_expansion--;
 282
 283       if (pfile->directive != &dtable[T_DEFINE])
 284         _cpp_remove_overlay (pfile);
 285     }
 286   /* We don't skip for an assembler #.  */
 287   else if (skip_line)
 288     {
 289       skip_rest_of_line (pfile);
 290       if (!pfile->keep_tokens)
 291         {
 292           pfile->cur_run = &pfile->base_run;
 293           pfile->cur_token = pfile->base_run.base;
 294         }
 295     }
 296
 297   /* Restore state.  */
 298   pfile->state.save_comments = ! CPP_OPTION (pfile, discard_comments);
 299   pfile->state.in_directive = 0;
 300   pfile->state.in_expression = 0;
 301   pfile->state.angled_headers = 0;
 302   pfile->directive = 0;
 303 }
 304
 305 /* Prepare to handle the directive in pfile->directive.  */
 306 static void
 307 prepare_directive_trad (cpp_reader *pfile)
 308 {
 309   if (pfile->directive != &dtable[T_DEFINE])
 310     {
 311       bool no_expand = (pfile->directive
 312                         && ! (pfile->directive->flags & EXPAND));
 313       bool was_skipping = pfile->state.skipping;
 314
 315       pfile->state.in_expression = (pfile->directive == &dtable[T_IF]
 316                                     || pfile->directive == &dtable[T_ELIF]);
 317       if (pfile->state.in_expression)
 318         pfile->state.skipping = false;
 319
 320       if (no_expand)
 321         pfile->state.prevent_expansion++;
 322       _cpp_scan_out_logical_line (pfile, NULL);
 323       if (no_expand)
 324         pfile->state.prevent_expansion--;
 325
 326       pfile->state.skipping = was_skipping;
 327       _cpp_overlay_buffer (pfile, pfile->out.base,
 328                            pfile->out.cur - pfile->out.base);
 329     }
 330
 331   /* Stop ISO C from expanding anything.  */
 332   pfile->state.prevent_expansion++;
 333 }
 334
 335 /* Output diagnostics for a directive DIR.  INDENTED is nonzero if
 336    the '#' was indented.  */
 337 static void
 338 directive_diagnostics (cpp_reader *pfile, const directive *dir, int indented)
 339 {
 340   /* Issue -pedantic warnings for extensions.  */
 341   if (CPP_PEDANTIC (pfile)
 342       && ! pfile->state.skipping
 343       && dir->origin == EXTENSION)
 344     cpp_error (pfile, CPP_DL_PEDWARN, "#%s is a GCC extension", dir->name);
 345
 346   /* Traditionally, a directive is ignored unless its # is in
 347      column 1.  Therefore in code intended to work with K+R
 348      compilers, directives added by C89 must have their #
 349      indented, and directives present in traditional C must not.
 350      This is true even of directives in skipped conditional
 351      blocks.  #elif cannot be used at all.  */
 352   if (CPP_WTRADITIONAL (pfile))
 353     {
 354       if (dir == &dtable[T_ELIF])
 355         cpp_error (pfile, CPP_DL_WARNING,
 356                    "suggest not using #elif in traditional C");
 357       else if (indented && dir->origin == KANDR)
 358         cpp_error (pfile, CPP_DL_WARNING,
 359                    "traditional C ignores #%s with the # indented",
 360                    dir->name);
 361       else if (!indented && dir->origin != KANDR)
 362         cpp_error (pfile, CPP_DL_WARNING,
 363                    "suggest hiding #%s from traditional C with an indented #",
 364                    dir->name);
 365     }
 366 }
 367
 368 /* Check if we have a known directive.  INDENTED is nonzero if the
 369    '#' of the directive was indented.  This function is in this file
 370    to save unnecessarily exporting dtable etc. to lex.c.  Returns
 371    nonzero if the line of tokens has been handled, zero if we should
 372    continue processing the line.  */
 373 int
 374 _cpp_handle_directive (cpp_reader *pfile, int indented)
 375 {
 376   const directive *dir = 0;
 377   const cpp_token *dname;
 378   bool was_parsing_args = pfile->state.parsing_args;
 379   bool was_discarding_output = pfile->state.discarding_output;
 380   int skip = 1;
 381
 382   if (was_discarding_output)
 383     pfile->state.prevent_expansion = 0;
 384
 385   if (was_parsing_args)
 386     {
 387       if (CPP_OPTION (pfile, pedantic))
 388         cpp_error (pfile, CPP_DL_PEDWARN,
 389              "embedding a directive within macro arguments is not portable");
 390       pfile->state.parsing_args = 0;
 391       pfile->state.prevent_expansion = 0;
 392     }
 393   start_directive (pfile);
 394   dname = _cpp_lex_token (pfile);
 395
 396   if (dname->type == CPP_NAME)
 397     {
 398       if (dname->val.node->is_directive)
 399         dir = &dtable[dname->val.node->directive_index];
 400     }
 401   /* We do not recognize the # followed by a number extension in
 402      assembler code.  */
 403   else if (dname->type == CPP_NUMBER && CPP_OPTION (pfile, lang) != CLK_ASM)
 404     {
 405       dir = &linemarker_dir;
 406       if (CPP_PEDANTIC (pfile) && ! CPP_OPTION (pfile, preprocessed)
 407           && ! pfile->state.skipping)
 408         cpp_error (pfile, CPP_DL_PEDWARN,
 409                    "style of line directive is a GCC extension");
 410     }
 411
 412   if (dir)
 413     {
 414       /* If we have a directive that is not an opening conditional,
 415          invalidate any control macro.  */
 416       if (! (dir->flags & IF_COND))
 417         pfile->mi_valid = false;
 418
 419       /* Kluge alert.  In order to be sure that code like this
 420
 421          #define HASH #
 422          HASH define foo bar
 423
 424          does not cause '#define foo bar' to get executed when
 425          compiled with -save-temps, we recognize directives in
 426          -fpreprocessed mode only if the # is in column 1.  macro.c
 427          puts a space in front of any '#' at the start of a macro.
 428
 429          We exclude the -fdirectives-only case because macro expansion
 430          has not been performed yet, and block comments can cause spaces
 431          to preceed the directive.  */
 432       if (CPP_OPTION (pfile, preprocessed)
 433           && !CPP_OPTION (pfile, directives_only)
 434           && (indented || !(dir->flags & IN_I)))
 435         {
 436           skip = 0;
 437           dir = 0;
 438         }
 439       else
 440         {
 441           /* In failed conditional groups, all non-conditional
 442              directives are ignored.  Before doing that, whether
 443              skipping or not, we should lex angle-bracketed headers
 444              correctly, and maybe output some diagnostics.  */
 445           pfile->state.angled_headers = dir->flags & INCL;
 446           pfile->state.directive_wants_padding = dir->flags & INCL;
 447           if (! CPP_OPTION (pfile, preprocessed))
 448             directive_diagnostics (pfile, dir, indented);
 449           if (pfile->state.skipping && !(dir->flags & COND))
 450             dir = 0;
 451         }
 452     }
 453   else if (dname->type == CPP_EOF)
 454     ;   /* CPP_EOF is the "null directive".  */
 455   else
 456     {
 457       /* An unknown directive.  Don't complain about it in assembly
 458          source: we don't know where the comments are, and # may
 459          introduce assembler pseudo-ops.  Don't complain about invalid
 460          directives in skipped conditional groups (6.10 p4).  */
 461       if (CPP_OPTION (pfile, lang) == CLK_ASM)
 462         skip = 0;
 463       else if (!pfile->state.skipping)
 464         cpp_error (pfile, CPP_DL_ERROR, "invalid preprocessing directive #%s",
 465                    cpp_token_as_text (pfile, dname));
 466     }
 467
 468   pfile->directive = dir;
 469   if (CPP_OPTION (pfile, traditional))
 470     prepare_directive_trad (pfile);
 471
 472   if (dir)
 473     pfile->directive->handler (pfile);
 474   else if (skip == 0)
 475     _cpp_backup_tokens (pfile, 1);
 476
 477   end_directive (pfile, skip);
 478   if (was_parsing_args)
 479     {
 480       /* Restore state when within macro args.  */
 481       pfile->state.parsing_args = 2;
 482       pfile->state.prevent_expansion = 1;
 483     }
 484   if (was_discarding_output)
 485     pfile->state.prevent_expansion = 1;
 486   return skip;
 487 }
 488
 489 /* Directive handler wrapper used by the command line option
 490    processor.  BUF is \n terminated.  */
 491 static void
 492 run_directive (cpp_reader *pfile, int dir_no, const char *buf, size_t count)
 493 {
 494   cpp_push_buffer (pfile, (const uchar *) buf, count,
 495                    /* from_stage3 */ true);
 496   start_directive (pfile);
 497
 498   /* This is a short-term fix to prevent a leading '#' being
 499      interpreted as a directive.  */
 500   _cpp_clean_line (pfile);
 501
 502   pfile->directive = &dtable[dir_no];
 503   if (CPP_OPTION (pfile, traditional))
 504     prepare_directive_trad (pfile);
 505   pfile->directive->handler (pfile);
 506   end_directive (pfile, 1);
 507   _cpp_pop_buffer (pfile);
 508 }
 509
 510 /* Checks for validity the macro name in #define, #undef, #ifdef and
 511    #ifndef directives.  IS_DEF_OR_UNDEF is true if this call is
 512    processing a #define or #undefine directive, and false
 513    otherwise.  */
 514 static cpp_hashnode *
 515 lex_macro_node (cpp_reader *pfile, bool is_def_or_undef)
 516 {
 517   const cpp_token *token = _cpp_lex_token (pfile);
 518
 519   /* The token immediately after #define must be an identifier.  That
 520      identifier may not be "defined", per C99 6.10.8p4.
 521      In C++, it may not be any of the "named operators" either,
 522      per C++98 [lex.digraph], [lex.key].
 523      Finally, the identifier may not have been poisoned.  (In that case
 524      the lexer has issued the error message for us.)  */
 525
 526   if (token->type == CPP_NAME)
 527     {
 528       cpp_hashnode *node = token->val.node;
 529
 530       if (is_def_or_undef && node == pfile->spec_nodes.n_defined)
 531         cpp_error (pfile, CPP_DL_ERROR,
 532                    "\"defined\" cannot be used as a macro name");
 533       else if (! (node->flags & NODE_POISONED))
 534         return node;
 535     }
 536   else if (token->flags & NAMED_OP)
 537     cpp_error (pfile, CPP_DL_ERROR,
 538        "\"%s\" cannot be used as a macro name as it is an operator in C++",
 539                NODE_NAME (token->val.node));
 540   else if (token->type == CPP_EOF)
 541     cpp_error (pfile, CPP_DL_ERROR, "no macro name given in #%s directive",
 542                pfile->directive->name);
 543   else
 544     cpp_error (pfile, CPP_DL_ERROR, "macro names must be identifiers");
 545
 546   return NULL;
 547 }
 548
 549 /* Process a #define directive.  Most work is done in macro.c.  */
 550 static void
 551 do_define (cpp_reader *pfile)
 552 {
 553   cpp_hashnode *node = lex_macro_node (pfile, true);
 554
 555   if (node)
 556     {
 557       /* If we have been requested to expand comments into macros,
 558          then re-enable saving of comments.  */
 559       pfile->state.save_comments =
 560         ! CPP_OPTION (pfile, discard_comments_in_macro_exp);
 561
 562       if (_cpp_create_definition (pfile, node))
 563         if (pfile->cb.define)
 564           pfile->cb.define (pfile, pfile->directive_line, node);
 565     }
 566 }
 567
 568 /* Handle #undef.  Mark the identifier NT_VOID in the hash table.  */
 569 static void
 570 do_undef (cpp_reader *pfile)
 571 {
 572   cpp_hashnode *node = lex_macro_node (pfile, true);
 573
 574   if (node)
 575     {
 576       if (pfile->cb.undef)
 577         pfile->cb.undef (pfile, pfile->directive_line, node);
 578
 579       /* 6.10.3.5 paragraph 2: [#undef] is ignored if the specified
 580          identifier is not currently defined as a macro name.  */
 581       if (node->type == NT_MACRO)
 582         {
 583           if (node->flags & NODE_WARN)
 584             cpp_error (pfile, CPP_DL_WARNING,
 585                        "undefining \"%s\"", NODE_NAME (node));
 586
 587           if (CPP_OPTION (pfile, warn_unused_macros))
 588             _cpp_warn_if_unused_macro (pfile, node, NULL);
 589
 590           _cpp_free_definition (node);
 591         }
 592     }
 593
 594   check_eol (pfile);
 595 }
 596
 597 /* Undefine a single macro/assertion/whatever.  */
 598
 599 static int
 600 undefine_macros (cpp_reader *pfile ATTRIBUTE_UNUSED, cpp_hashnode *h,
 601                  void *data_p ATTRIBUTE_UNUSED)
 602 {
 603   /* Body of _cpp_free_definition inlined here for speed.
 604      Macros and assertions no longer have anything to free.  */
 605   h->type = NT_VOID;
 606   h->flags &= ~(NODE_POISONED|NODE_BUILTIN|NODE_DISABLED);
 607   return 1;
 608 }
 609
 610 /* Undefine all macros and assertions.  */
 611
 612 void
 613 cpp_undef_all (cpp_reader *pfile)
 614 {
 615   cpp_forall_identifiers (pfile, undefine_macros, NULL);
 616 }
 617
 618
 619 /* Helper routine used by parse_include.  Reinterpret the current line
 620    as an h-char-sequence (< ... >); we are looking at the first token
 621    after the <.  Returns a malloced filename.  */
 622 static char *
 623 glue_header_name (cpp_reader *pfile)
 624 {
 625   const cpp_token *token;
 626   char *buffer;
 627   size_t len, total_len = 0, capacity = 1024;
 628
 629   /* To avoid lexed tokens overwriting our glued name, we can only
 630      allocate from the string pool once we've lexed everything.  */
 631   buffer = XNEWVEC (char, capacity);
 632   for (;;)
 633     {
 634       token = get_token_no_padding (pfile);
 635
 636       if (token->type == CPP_GREATER)
 637         break;
 638       if (token->type == CPP_EOF)
 639         {
 640           cpp_error (pfile, CPP_DL_ERROR, "missing terminating > character");
 641           break;
 642         }
 643
 644       len = cpp_token_len (token) + 2; /* Leading space, terminating \0.  */
 645       if (total_len + len > capacity)
 646         {
 647           capacity = (capacity + len) * 2;
 648           buffer = XRESIZEVEC (char, buffer, capacity);
 649         }
 650
 651       if (token->flags & PREV_WHITE)
 652         buffer[total_len++] = ' ';
 653
 654       total_len = (cpp_spell_token (pfile, token, (uchar *) &buffer[total_len],
 655                                     true)
 656                    - (uchar *) buffer);
 657     }
 658
 659   buffer[total_len] = '\0';
 660   return buffer;
 661 }
 662
 663 /* Returns the file name of #include, #include_next, #import and
 664    #pragma dependency.  The string is malloced and the caller should
 665    free it.  Returns NULL on error.  */
 666 static const char *
 667 parse_include (cpp_reader *pfile, int *pangle_brackets,
 668                const cpp_token ***buf)
 669 {
 670   char *fname;
 671   const cpp_token *header;
 672
 673   /* Allow macro expansion.  */
 674   header = get_token_no_padding (pfile);
 675   if (header->type == CPP_STRING || header->type == CPP_HEADER_NAME)
 676     {
 677       fname = XNEWVEC (char, header->val.str.len - 1);
 678       memcpy (fname, header->val.str.text + 1, header->val.str.len - 2);
 679       fname[header->val.str.len - 2] = '\0';
 680       *pangle_brackets = header->type == CPP_HEADER_NAME;
 681     }
 682   else if (header->type == CPP_LESS)
 683     {
 684       fname = glue_header_name (pfile);
 685       *pangle_brackets = 1;
 686     }
 687   else
 688     {
 689       const unsigned char *dir;
 690
 691       if (pfile->directive == &dtable[T_PRAGMA])
 692         dir = U"pragma dependency";
 693       else
 694         dir = pfile->directive->name;
 695       cpp_error (pfile, CPP_DL_ERROR, "#%s expects \"FILENAME\" or <FILENAME>",
 696                  dir);
 697
 698       return NULL;
 699     }
 700
 701   if (pfile->directive == &dtable[T_PRAGMA])
 702     {
 703       /* This pragma allows extra tokens after the file name.  */
 704     }
 705   else if (buf == NULL || CPP_OPTION (pfile, discard_comments))
 706     check_eol (pfile);
 707   else
 708     {
 709       /* If we are not discarding comments, then gather them while
 710          doing the eol check.  */
 711       *buf = check_eol_return_comments (pfile);
 712     }
 713
 714   return fname;
 715 }
 716
 717 /* Handle #include, #include_next and #import.  */
 718 static void
 719 do_include_common (cpp_reader *pfile, enum include_type type)
 720 {
 721   const char *fname;
 722   int angle_brackets;
 723   const cpp_token **buf = NULL;
 724
 725   /* Re-enable saving of comments if requested, so that the include
 726      callback can dump comments which follow #include.  */
 727   pfile->state.save_comments = ! CPP_OPTION (pfile, discard_comments);
 728
 729   fname = parse_include (pfile, &angle_brackets, &buf);
 730   if (!fname)
 731     {
 732       if (buf)
 733         XDELETEVEC (buf);
 734       return;
 735     }
 736
 737   if (!*fname)
 738   {
 739     cpp_error (pfile, CPP_DL_ERROR, "empty filename in #%s",
 740                pfile->directive->name);
 741     XDELETEVEC (fname);
 742     if (buf)
 743       XDELETEVEC (buf);
 744     return;
 745   }
 746
 747   /* Prevent #include recursion.  */
 748   if (pfile->line_table->depth >= CPP_STACK_MAX)
 749     cpp_error (pfile, CPP_DL_ERROR, "#include nested too deeply");
 750   else
 751     {
 752       /* Get out of macro context, if we are.  */
 753       skip_rest_of_line (pfile);
 754
 755       if (pfile->cb.include)
 756         pfile->cb.include (pfile, pfile->directive_line,
 757                            pfile->directive->name, fname, angle_brackets,
 758                            buf);
 759
 760       _cpp_stack_include (pfile, fname, angle_brackets, type);
 761     }
 762
 763   XDELETEVEC (fname);
 764   if (buf)
 765     XDELETEVEC (buf);
 766 }
 767
 768 static void
 769 do_include (cpp_reader *pfile)
 770 {
 771   do_include_common (pfile, IT_INCLUDE);
 772 }
 773
 774 static void
 775 do_import (cpp_reader *pfile)
 776 {
 777   do_include_common (pfile, IT_IMPORT);
 778 }
 779
 780 static void
 781 do_include_next (cpp_reader *pfile)
 782 {
 783   enum include_type type = IT_INCLUDE_NEXT;
 784
 785   /* If this is the primary source file, warn and use the normal
 786      search logic.  */
 787   if (cpp_in_primary_file (pfile))
 788     {
 789       cpp_error (pfile, CPP_DL_WARNING,
 790                  "#include_next in primary source file");
 791       type = IT_INCLUDE;
 792     }
 793   do_include_common (pfile, type);
 794 }
 795
 796 /* Subroutine of do_linemarker.  Read possible flags after file name.
 797    LAST is the last flag seen; 0 if this is the first flag. Return the
 798    flag if it is valid, 0 at the end of the directive. Otherwise
 799    complain.  */
 800 static unsigned int
 801 read_flag (cpp_reader *pfile, unsigned int last)
 802 {
 803   const cpp_token *token = _cpp_lex_token (pfile);
 804
 805   if (token->type == CPP_NUMBER && token->val.str.len == 1)
 806     {
 807       unsigned int flag = token->val.str.text[0] - '0';
 808
 809       if (flag > last && flag <= 4
 810           && (flag != 4 || last == 3)
 811           && (flag != 2 || last == 0))
 812         return flag;
 813     }
 814
 815   if (token->type != CPP_EOF)
 816     cpp_error (pfile, CPP_DL_ERROR, "invalid flag \"%s\" in line directive",
 817                cpp_token_as_text (pfile, token));
 818   return 0;
 819 }
 820
 821 /* Subroutine of do_line and do_linemarker.  Convert a number in STR,
 822    of length LEN, to binary; store it in NUMP, and return 0 if the
 823    number was well-formed, 1 if not.  Temporary, hopefully.  */
 824 static int
 825 strtoul_for_line (const uchar *str, unsigned int len, long unsigned int *nump)
 826 {
 827   unsigned long reg = 0;
 828   uchar c;
 829   while (len--)
 830     {
 831       c = *str++;
 832       if (!ISDIGIT (c))
 833         return 1;
 834       reg *= 10;
 835       reg += c - '0';
 836     }
 837   *nump = reg;
 838   return 0;
 839 }
 840
 841 /* Interpret #line command.
 842    Note that the filename string (if any) is a true string constant
 843    (escapes are interpreted), unlike in #line.  */
 844 static void
 845 do_line (cpp_reader *pfile)
 846 {
 847   const struct line_maps *line_table = pfile->line_table;
 848   const struct line_map *map = &line_table->maps[line_table->used - 1];
 849
 850   /* skip_rest_of_line() may cause line table to be realloc()ed so note down
 851      sysp right now.  */
 852
 853   unsigned char map_sysp = map->sysp;
 854   const cpp_token *token;
 855   const char *new_file = map->to_file;
 856   unsigned long new_lineno;
 857
 858   /* C99 raised the minimum limit on #line numbers.  */
 859   unsigned int cap = CPP_OPTION (pfile, c99) ? 2147483647 : 32767;
 860
 861   /* #line commands expand macros.  */
 862   token = cpp_get_token (pfile);
 863   if (token->type != CPP_NUMBER
 864       || strtoul_for_line (token->val.str.text, token->val.str.len,
 865                            &new_lineno))
 866     {
 867       cpp_error (pfile, CPP_DL_ERROR,
 868                  "\"%s\" after #line is not a positive integer",
 869                  cpp_token_as_text (pfile, token));
 870       return;
 871     }
 872
 873   if (CPP_PEDANTIC (pfile) && (new_lineno == 0 || new_lineno > cap))
 874     cpp_error (pfile, CPP_DL_PEDWARN, "line number out of range");
 875
 876   token = cpp_get_token (pfile);
 877   if (token->type == CPP_STRING)
 878     {
 879       cpp_string s = { 0, 0 };
 880       if (cpp_interpret_string_notranslate (pfile, &token->val.str, 1,
 881                                             &s, false))
 882         new_file = (const char *)s.text;
 883       check_eol (pfile);
 884     }
 885   else if (token->type != CPP_EOF)
 886     {
 887       cpp_error (pfile, CPP_DL_ERROR, "\"%s\" is not a valid filename",
 888                  cpp_token_as_text (pfile, token));
 889       return;
 890     }
 891
 892   skip_rest_of_line (pfile);
 893   _cpp_do_file_change (pfile, LC_RENAME, new_file, new_lineno,
 894                        map_sysp);
 895 }
 896
 897 /* Interpret the # 44 "file" [flags] notation, which has slightly
 898    different syntax and semantics from #line:  Flags are allowed,
 899    and we never complain about the line number being too big.  */
 900 static void
 901 do_linemarker (cpp_reader *pfile)
 902 {
 903   const struct line_maps *line_table = pfile->line_table;
 904   const struct line_map *map = &line_table->maps[line_table->used - 1];
 905   const cpp_token *token;
 906   const char *new_file = map->to_file;
 907   unsigned long new_lineno;
 908   unsigned int new_sysp = map->sysp;
 909   enum lc_reason reason = LC_RENAME;
 910   int flag;
 911
 912   /* Back up so we can get the number again.  Putting this in
 913      _cpp_handle_directive risks two calls to _cpp_backup_tokens in
 914      some circumstances, which can segfault.  */
 915   _cpp_backup_tokens (pfile, 1);
 916
 917   /* #line commands expand macros.  */
 918   token = cpp_get_token (pfile);
 919   if (token->type != CPP_NUMBER
 920       || strtoul_for_line (token->val.str.text, token->val.str.len,
 921                            &new_lineno))
 922     {
 923       cpp_error (pfile, CPP_DL_ERROR,
 924                  "\"%s\" after # is not a positive integer",
 925                  cpp_token_as_text (pfile, token));
 926       return;
 927     }
 928
 929   token = cpp_get_token (pfile);
 930   if (token->type == CPP_STRING)
 931     {
 932       cpp_string s = { 0, 0 };
 933       if (cpp_interpret_string_notranslate (pfile, &token->val.str,
 934                                             1, &s, false))
 935         new_file = (const char *)s.text;
 936
 937       new_sysp = 0;
 938       flag = read_flag (pfile, 0);
 939       if (flag == 1)
 940         {
 941           reason = LC_ENTER;
 942           /* Fake an include for cpp_included ().  */
 943           _cpp_fake_include (pfile, new_file);
 944           flag = read_flag (pfile, flag);
 945         }
 946       else if (flag == 2)
 947         {
 948           reason = LC_LEAVE;
 949           flag = read_flag (pfile, flag);
 950         }
 951       if (flag == 3)
 952         {
 953           new_sysp = 1;
 954           flag = read_flag (pfile, flag);
 955           if (flag == 4)
 956             new_sysp = 2;
 957         }
 958       pfile->buffer->sysp = new_sysp;
 959
 960       check_eol (pfile);
 961     }
 962   else if (token->type != CPP_EOF)
 963     {
 964       cpp_error (pfile, CPP_DL_ERROR, "\"%s\" is not a valid filename",
 965                  cpp_token_as_text (pfile, token));
 966       return;
 967     }
 968
 969   skip_rest_of_line (pfile);
 970   _cpp_do_file_change (pfile, reason, new_file, new_lineno, new_sysp);
 971 }
 972
 973 /* Arrange the file_change callback.  pfile->line has changed to
 974    FILE_LINE of TO_FILE, for reason REASON.  SYSP is 1 for a system
 975    header, 2 for a system header that needs to be extern "C" protected,
 976    and zero otherwise.  */
 977 void
 978 _cpp_do_file_change (cpp_reader *pfile, enum lc_reason reason,
 979                      const char *to_file, unsigned int file_line,
 980                      unsigned int sysp)
 981 {
 982   const struct line_map *map = linemap_add (pfile->line_table, reason, sysp,
 983                                             to_file, file_line);
 984   if (map != NULL)
 985     linemap_line_start (pfile->line_table, map->to_line, 127);
 986
 987   if (pfile->cb.file_change)
 988     pfile->cb.file_change (pfile, map);
 989 }
 990
 991 /* Report a warning or error detected by the program we are
 992    processing.  Use the directive's tokens in the error message.  */
 993 static void
 994 do_diagnostic (cpp_reader *pfile, int code, int print_dir)
 995 {
 996   if (_cpp_begin_message (pfile, code, pfile->cur_token[-1].src_loc, 0))
 997     {
 998       if (print_dir)
 999         fprintf (stderr, "#%s ", pfile->directive->name);
1000       pfile->state.prevent_expansion++;
1001       cpp_output_line (pfile, stderr);
1002       pfile->state.prevent_expansion--;
1003     }
1004 }
1005
1006 static void
1007 do_error (cpp_reader *pfile)
1008 {
1009   do_diagnostic (pfile, CPP_DL_ERROR, 1);
1010 }
1011
1012 static void
1013 do_warning (cpp_reader *pfile)
1014 {
1015   /* We want #warning diagnostics to be emitted in system headers too.  */
1016   do_diagnostic (pfile, CPP_DL_WARNING_SYSHDR, 1);
1017 }
1018
1019 /* Report program identification.  */
1020 static void
1021 do_ident (cpp_reader *pfile)
1022 {
1023   const cpp_token *str = cpp_get_token (pfile);
1024
1025   if (str->type != CPP_STRING)
1026     cpp_error (pfile, CPP_DL_ERROR, "invalid #%s directive",
1027                pfile->directive->name);
1028   else if (pfile->cb.ident)
1029     pfile->cb.ident (pfile, pfile->directive_line, &str->val.str);
1030
1031   check_eol (pfile);
1032 }
1033
1034 /* Lookup a PRAGMA name in a singly-linked CHAIN.  Returns the
1035    matching entry, or NULL if none is found.  The returned entry could
1036    be the start of a namespace chain, or a pragma.  */
1037 static struct pragma_entry *
1038 lookup_pragma_entry (struct pragma_entry *chain, const cpp_hashnode *pragma)
1039 {
1040   while (chain && chain->pragma != pragma)
1041     chain = chain->next;
1042
1043   return chain;
1044 }
1045
1046 /* Create and insert a blank pragma entry at the beginning of a
1047    singly-linked CHAIN.  */
1048 static struct pragma_entry *
1049 new_pragma_entry (cpp_reader *pfile, struct pragma_entry **chain)
1050 {
1051   struct pragma_entry *new_entry;
1052
1053   new_entry = (struct pragma_entry *)
1054     _cpp_aligned_alloc (pfile, sizeof (struct pragma_entry));
1055
1056   memset (new_entry, 0, sizeof (struct pragma_entry));
1057   new_entry->next = *chain;
1058
1059   *chain = new_entry;
1060   return new_entry;
1061 }
1062
1063 /* Register a pragma NAME in namespace SPACE.  If SPACE is null, it
1064    goes in the global namespace.  */
1065 static struct pragma_entry *
1066 register_pragma_1 (cpp_reader *pfile, const char *space, const char *name,
1067                    bool allow_name_expansion)
1068 {
1069   struct pragma_entry **chain = &pfile->pragmas;
1070   struct pragma_entry *entry;
1071   const cpp_hashnode *node;
1072
1073   if (space)
1074     {
1075       node = cpp_lookup (pfile, U space, strlen (space));
1076       entry = lookup_pragma_entry (*chain, node);
1077       if (!entry)
1078         {
1079           entry = new_pragma_entry (pfile, chain);
1080           entry->pragma = node;
1081           entry->is_nspace = true;
1082           entry->allow_expansion = allow_name_expansion;
1083         }
1084       else if (!entry->is_nspace)
1085         goto clash;
1086       else if (entry->allow_expansion != allow_name_expansion)
1087         {
1088           cpp_error (pfile, CPP_DL_ICE,
1089                      "registering pragmas in namespace \"%s\" with mismatched "
1090                      "name expansion", space);
1091           return NULL;
1092         }
1093       chain = &entry->u.space;
1094     }
1095   else if (allow_name_expansion)
1096     {
1097       cpp_error (pfile, CPP_DL_ICE,
1098                  "registering pragma \"%s\" with name expansion "
1099                  "and no namespace", name);
1100       return NULL;
1101     }
1102
1103   /* Check for duplicates.  */
1104   node = cpp_lookup (pfile, U name, strlen (name));
1105   entry = lookup_pragma_entry (*chain, node);
1106   if (entry == NULL)
1107     {
1108       entry = new_pragma_entry (pfile, chain);
1109       entry->pragma = node;
1110       return entry;
1111     }
1112
1113   if (entry->is_nspace)
1114     clash:
1115     cpp_error (pfile, CPP_DL_ICE,
1116                "registering \"%s\" as both a pragma and a pragma namespace",
1117                NODE_NAME (node));
1118   else if (space)
1119     cpp_error (pfile, CPP_DL_ICE, "#pragma %s %s is already registered",
1120                space, name);
1121   else
1122     cpp_error (pfile, CPP_DL_ICE, "#pragma %s is already registered", name);
1123
1124   return NULL;
1125 }
1126
1127 /* Register a cpplib internal pragma SPACE NAME with HANDLER.  */
1128 static void
1129 register_pragma_internal (cpp_reader *pfile, const char *space,
1130                           const char *name, pragma_cb handler)
1131 {
1132   struct pragma_entry *entry;
1133
1134   entry = register_pragma_1 (pfile, space, name, false);
1135   entry->is_internal = true;
1136   entry->u.handler = handler;
1137 }
1138
1139 /* Register a pragma NAME in namespace SPACE.  If SPACE is null, it
1140    goes in the global namespace.  HANDLER is the handler it will call,
1141    which must be non-NULL.  If ALLOW_EXPANSION is set, allow macro
1142    expansion while parsing pragma NAME.  This function is exported
1143    from libcpp. */
1144 void
1145 cpp_register_pragma (cpp_reader *pfile, const char *space, const char *name,
1146                      pragma_cb handler, bool allow_expansion)
1147 {
1148   struct pragma_entry *entry;
1149
1150   if (!handler)
1151     {
1152       cpp_error (pfile, CPP_DL_ICE, "registering pragma with NULL handler");
1153       return;
1154     }
1155
1156   entry = register_pragma_1 (pfile, space, name, false);
1157   if (entry)
1158     {
1159       entry->allow_expansion = allow_expansion;
1160       entry->u.handler = handler;
1161     }
1162 }
1163
1164 /* Similarly, but create mark the pragma for deferred processing.
1165    When found, a CPP_PRAGMA token will be insertted into the stream
1166    with IDENT in the token->u.pragma slot.  */
1167 void
1168 cpp_register_deferred_pragma (cpp_reader *pfile, const char *space,
1169                               const char *name, unsigned int ident,
1170                               bool allow_expansion, bool allow_name_expansion)
1171 {
1172   struct pragma_entry *entry;
1173
1174   entry = register_pragma_1 (pfile, space, name, allow_name_expansion);
1175   if (entry)
1176     {
1177       entry->is_deferred = true;
1178       entry->allow_expansion = allow_expansion;
1179       entry->u.ident = ident;
1180     }
1181 }
1182
1183 /* Register the pragmas the preprocessor itself handles.  */
1184 void
1185 _cpp_init_internal_pragmas (cpp_reader *pfile)
1186 {
1187   /* Pragmas in the global namespace.  */
1188   register_pragma_internal (pfile, 0, "once", do_pragma_once);
1189
1190   /* New GCC-specific pragmas should be put in the GCC namespace.  */
1191   register_pragma_internal (pfile, "GCC", "poison", do_pragma_poison);
1192   register_pragma_internal (pfile, "GCC", "system_header",
1193                             do_pragma_system_header);
1194   register_pragma_internal (pfile, "GCC", "dependency", do_pragma_dependency);
1195 }
1196
1197 /* Return the number of registered pragmas in PE.  */
1198
1199 static int
1200 count_registered_pragmas (struct pragma_entry *pe)
1201 {
1202   int ct = 0;
1203   for (; pe != NULL; pe = pe->next)
1204     {
1205       if (pe->is_nspace)
1206         ct += count_registered_pragmas (pe->u.space);
1207       ct++;
1208     }
1209   return ct;
1210 }
1211
1212 /* Save into SD the names of the registered pragmas referenced by PE,
1213    and return a pointer to the next free space in SD.  */
1214
1215 static char **
1216 save_registered_pragmas (struct pragma_entry *pe, char **sd)
1217 {
1218   for (; pe != NULL; pe = pe->next)
1219     {
1220       if (pe->is_nspace)
1221         sd = save_registered_pragmas (pe->u.space, sd);
1222       *sd++ = (char *) xmemdup (HT_STR (&pe->pragma->ident),
1223                                 HT_LEN (&pe->pragma->ident),
1224                                 HT_LEN (&pe->pragma->ident) + 1);
1225     }
1226   return sd;
1227 }
1228
1229 /* Return a newly-allocated array which saves the names of the
1230    registered pragmas.  */
1231
1232 char **
1233 _cpp_save_pragma_names (cpp_reader *pfile)
1234 {
1235   int ct = count_registered_pragmas (pfile->pragmas);
1236   char **result = XNEWVEC (char *, ct);
1237   (void) save_registered_pragmas (pfile->pragmas, result);
1238   return result;
1239 }
1240
1241 /* Restore from SD the names of the registered pragmas referenced by PE,
1242    and return a pointer to the next unused name in SD.  */
1243
1244 static char **
1245 restore_registered_pragmas (cpp_reader *pfile, struct pragma_entry *pe,
1246                             char **sd)
1247 {
1248   for (; pe != NULL; pe = pe->next)
1249     {
1250       if (pe->is_nspace)
1251         sd = restore_registered_pragmas (pfile, pe->u.space, sd);
1252       pe->pragma = cpp_lookup (pfile, U *sd, strlen (*sd));
1253       free (*sd);
1254       sd++;
1255     }
1256   return sd;
1257 }
1258
1259 /* Restore the names of the registered pragmas from SAVED.  */
1260
1261 void
1262 _cpp_restore_pragma_names (cpp_reader *pfile, char **saved)
1263 {
1264   (void) restore_registered_pragmas (pfile, pfile->pragmas, saved);
1265   free (saved);
1266 }
1267
1268 /* Pragmata handling.  We handle some, and pass the rest on to the
1269    front end.  C99 defines three pragmas and says that no macro
1270    expansion is to be performed on them; whether or not macro
1271    expansion happens for other pragmas is implementation defined.
1272    This implementation allows for a mix of both, since GCC did not
1273    traditionally macro expand its (few) pragmas, whereas OpenMP
1274    specifies that macro expansion should happen.  */
1275 static void
1276 do_pragma (cpp_reader *pfile)
1277 {
1278   const struct pragma_entry *p = NULL;
1279   const cpp_token *token, *pragma_token = pfile->cur_token;
1280   cpp_token ns_token;
1281   unsigned int count = 1;
1282
1283   pfile->state.prevent_expansion++;
1284
1285   token = cpp_get_token (pfile);
1286   ns_token = *token;
1287   if (token->type == CPP_NAME)
1288     {
1289       p = lookup_pragma_entry (pfile->pragmas, token->val.node);
1290       if (p && p->is_nspace)
1291         {
1292           bool allow_name_expansion = p->allow_expansion;
1293           if (allow_name_expansion)
1294             pfile->state.prevent_expansion--;
1295           token = cpp_get_token (pfile);
1296           if (token->type == CPP_NAME)
1297             p = lookup_pragma_entry (p->u.space, token->val.node);
1298           else
1299             p = NULL;
1300           if (allow_name_expansion)
1301             pfile->state.prevent_expansion++;
1302           count = 2;
1303         }
1304     }
1305
1306   if (p)
1307     {
1308       if (p->is_deferred)
1309         {
1310           pfile->directive_result.src_loc = pragma_token->src_loc;
1311           pfile->directive_result.type = CPP_PRAGMA;
1312           pfile->directive_result.flags = pragma_token->flags;
1313           pfile->directive_result.val.pragma = p->u.ident;
1314           pfile->state.in_deferred_pragma = true;
1315           pfile->state.pragma_allow_expansion = p->allow_expansion;
1316           if (!p->allow_expansion)
1317             pfile->state.prevent_expansion++;
1318         }
1319       else
1320         {
1321           /* Since the handler below doesn't get the line number, that
1322              it might need for diagnostics, make sure it has the right
1323              numbers in place.  */
1324           if (pfile->cb.line_change)
1325             (*pfile->cb.line_change) (pfile, pragma_token, false);
1326           if (p->allow_expansion)
1327             pfile->state.prevent_expansion--;
1328           (*p->u.handler) (pfile);
1329           if (p->allow_expansion)
1330             pfile->state.prevent_expansion++;
1331         }
1332     }
1333   else if (pfile->cb.def_pragma)
1334     {
1335       if (count == 1 || pfile->context->prev == NULL)
1336         _cpp_backup_tokens (pfile, count);
1337       else
1338         {
1339           /* Invalid name comes from macro expansion, _cpp_backup_tokens
1340              won't allow backing 2 tokens.  */
1341           /* ??? The token buffer is leaked.  Perhaps if def_pragma hook
1342              reads both tokens, we could perhaps free it, but if it doesn't,
1343              we don't know the exact lifespan.  */
1344           cpp_token *toks = XNEWVEC (cpp_token, 2);
1345           toks[0] = ns_token;
1346           toks[0].flags |= NO_EXPAND;
1347           toks[1] = *token;
1348           toks[1].flags |= NO_EXPAND;
1349           _cpp_push_token_context (pfile, NULL, toks, 2);
1350         }
1351       pfile->cb.def_pragma (pfile, pfile->directive_line);
1352     }
1353
1354   pfile->state.prevent_expansion--;
1355 }
1356
1357 /* Handle #pragma once.  */
1358 static void
1359 do_pragma_once (cpp_reader *pfile)
1360 {
1361   if (cpp_in_primary_file (pfile))
1362     cpp_error (pfile, CPP_DL_WARNING, "#pragma once in main file");
1363
1364   check_eol (pfile);
1365   _cpp_mark_file_once_only (pfile, pfile->buffer->file);
1366 }
1367
1368 /* Handle #pragma GCC poison, to poison one or more identifiers so
1369    that the lexer produces a hard error for each subsequent usage.  */
1370 static void
1371 do_pragma_poison (cpp_reader *pfile)
1372 {
1373   const cpp_token *tok;
1374   cpp_hashnode *hp;
1375
1376   pfile->state.poisoned_ok = 1;
1377   for (;;)
1378     {
1379       tok = _cpp_lex_token (pfile);
1380       if (tok->type == CPP_EOF)
1381         break;
1382       if (tok->type != CPP_NAME)
1383         {
1384           cpp_error (pfile, CPP_DL_ERROR,
1385                      "invalid #pragma GCC poison directive");
1386           break;
1387         }
1388
1389       hp = tok->val.node;
1390       if (hp->flags & NODE_POISONED)
1391         continue;
1392
1393       if (hp->type == NT_MACRO)
1394         cpp_error (pfile, CPP_DL_WARNING, "poisoning existing macro \"%s\"",
1395                    NODE_NAME (hp));
1396       _cpp_free_definition (hp);
1397       hp->flags |= NODE_POISONED | NODE_DIAGNOSTIC;
1398     }
1399   pfile->state.poisoned_ok = 0;
1400 }
1401
1402 /* Mark the current header as a system header.  This will suppress
1403    some categories of warnings (notably those from -pedantic).  It is
1404    intended for use in system libraries that cannot be implemented in
1405    conforming C, but cannot be certain that their headers appear in a
1406    system include directory.  To prevent abuse, it is rejected in the
1407    primary source file.  */
1408 static void
1409 do_pragma_system_header (cpp_reader *pfile)
1410 {
1411   if (cpp_in_primary_file (pfile))
1412     cpp_error (pfile, CPP_DL_WARNING,
1413                "#pragma system_header ignored outside include file");
1414   else
1415     {
1416       check_eol (pfile);
1417       skip_rest_of_line (pfile);
1418       cpp_make_system_header (pfile, 1, 0);
1419     }
1420 }
1421
1422 /* Check the modified date of the current include file against a specified
1423    file. Issue a diagnostic, if the specified file is newer. We use this to
1424    determine if a fixed header should be refixed.  */
1425 static void
1426 do_pragma_dependency (cpp_reader *pfile)
1427 {
1428   const char *fname;
1429   int angle_brackets, ordering;
1430
1431   fname = parse_include (pfile, &angle_brackets, NULL);
1432   if (!fname)
1433     return;
1434
1435   ordering = _cpp_compare_file_date (pfile, fname, angle_brackets);
1436   if (ordering < 0)
1437     cpp_error (pfile, CPP_DL_WARNING, "cannot find source file %s", fname);
1438   else if (ordering > 0)
1439     {
1440       cpp_error (pfile, CPP_DL_WARNING,
1441                  "current file is older than %s", fname);
1442       if (cpp_get_token (pfile)->type != CPP_EOF)
1443         {
1444           _cpp_backup_tokens (pfile, 1);
1445           do_diagnostic (pfile, CPP_DL_WARNING, 0);
1446         }
1447     }
1448
1449   free ((void *) fname);
1450 }
1451
1452 /* Get a token but skip padding.  */
1453 static const cpp_token *
1454 get_token_no_padding (cpp_reader *pfile)
1455 {
1456   for (;;)
1457     {
1458       const cpp_token *result = cpp_get_token (pfile);
1459       if (result->type != CPP_PADDING)
1460         return result;
1461     }
1462 }
1463
1464 /* Check syntax is "(string-literal)".  Returns the string on success,
1465    or NULL on failure.  */
1466 static const cpp_token *
1467 get__Pragma_string (cpp_reader *pfile)
1468 {
1469   const cpp_token *string;
1470   const cpp_token *paren;
1471
1472   paren = get_token_no_padding (pfile);
1473   if (paren->type == CPP_EOF)
1474     _cpp_backup_tokens (pfile, 1);
1475   if (paren->type != CPP_OPEN_PAREN)
1476     return NULL;
1477
1478   string = get_token_no_padding (pfile);
1479   if (string->type == CPP_EOF)
1480     _cpp_backup_tokens (pfile, 1);
1481   if (string->type != CPP_STRING && string->type != CPP_WSTRING)
1482     return NULL;
1483
1484   paren = get_token_no_padding (pfile);
1485   if (paren->type == CPP_EOF)
1486     _cpp_backup_tokens (pfile, 1);
1487   if (paren->type != CPP_CLOSE_PAREN)
1488     return NULL;
1489
1490   return string;
1491 }
1492
1493 /* Destringize IN into a temporary buffer, by removing the first \ of
1494    \" and \\ sequences, and process the result as a #pragma directive.  */
1495 static void
1496 destringize_and_run (cpp_reader *pfile, const cpp_string *in)
1497 {
1498   const unsigned char *src, *limit;
1499   char *dest, *result;
1500   cpp_context *saved_context;
1501   cpp_token *saved_cur_token;
1502   tokenrun *saved_cur_run;
1503   cpp_token *toks;
1504   int count;
1505
1506   dest = result = (char *) alloca (in->len - 1);
1507   src = in->text + 1 + (in->text[0] == 'L');
1508   limit = in->text + in->len - 1;
1509   while (src < limit)
1510     {
1511       /* We know there is a character following the backslash.  */
1512       if (*src == '\\' && (src[1] == '\\' || src[1] == '"'))
1513         src++;
1514       *dest++ = *src++;
1515     }
1516   *dest = '\n';
1517
1518   /* Ugh; an awful kludge.  We are really not set up to be lexing
1519      tokens when in the middle of a macro expansion.  Use a new
1520      context to force cpp_get_token to lex, and so skip_rest_of_line
1521      doesn't go beyond the end of the text.  Also, remember the
1522      current lexing position so we can return to it later.
1523
1524      Something like line-at-a-time lexing should remove the need for
1525      this.  */
1526   saved_context = pfile->context;
1527   saved_cur_token = pfile->cur_token;
1528   saved_cur_run = pfile->cur_run;
1529
1530   pfile->context = XNEW (cpp_context);
1531   pfile->context->macro = 0;
1532   pfile->context->prev = 0;
1533   pfile->context->next = 0;
1534
1535   /* Inline run_directive, since we need to delay the _cpp_pop_buffer
1536      until we've read all of the tokens that we want.  */
1537   cpp_push_buffer (pfile, (const uchar *) result, dest - result,
1538                    /* from_stage3 */ true);
1539   /* ??? Antique Disgusting Hack.  What does this do?  */
1540   if (pfile->buffer->prev)
1541     pfile->buffer->file = pfile->buffer->prev->file;
1542
1543   start_directive (pfile);
1544   _cpp_clean_line (pfile);
1545   do_pragma (pfile);
1546   end_directive (pfile, 1);
1547
1548   /* We always insert at least one token, the directive result.  It'll
1549      either be a CPP_PADDING or a CPP_PRAGMA.  In the later case, we
1550      need to insert *all* of the tokens, including the CPP_PRAGMA_EOL.  */
1551
1552   /* If we're not handling the pragma internally, read all of the tokens from
1553      the string buffer now, while the string buffer is still installed.  */
1554   /* ??? Note that the token buffer allocated here is leaked.  It's not clear
1555      to me what the true lifespan of the tokens are.  It would appear that
1556      the lifespan is the entire parse of the main input stream, in which case
1557      this may not be wrong.  */
1558   if (pfile->directive_result.type == CPP_PRAGMA)
1559     {
1560       int maxcount;
1561
1562       count = 1;
1563       maxcount = 50;
1564       toks = XNEWVEC (cpp_token, maxcount);
1565       toks[0] = pfile->directive_result;
1566
1567       do
1568         {
1569           if (count == maxcount)
1570             {
1571               maxcount = maxcount * 3 / 2;
1572               toks = XRESIZEVEC (cpp_token, toks, maxcount);
1573             }
1574           toks[count] = *cpp_get_token (pfile);
1575           /* Macros have been already expanded by cpp_get_token
1576              if the pragma allowed expansion.  */
1577           toks[count++].flags |= NO_EXPAND;
1578         }
1579       while (toks[count-1].type != CPP_PRAGMA_EOL);
1580     }
1581   else
1582     {
1583       count = 1;
1584       toks = XNEW (cpp_token);
1585       toks[0] = pfile->directive_result;
1586
1587       /* If we handled the entire pragma internally, make sure we get the
1588          line number correct for the next token.  */
1589       if (pfile->cb.line_change)
1590         pfile->cb.line_change (pfile, pfile->cur_token, false);
1591     }
1592
1593   /* Finish inlining run_directive.  */
1594   pfile->buffer->file = NULL;
1595   _cpp_pop_buffer (pfile);
1596
1597   /* Reset the old macro state before ...  */
1598   XDELETE (pfile->context);
1599   pfile->context = saved_context;
1600   pfile->cur_token = saved_cur_token;
1601   pfile->cur_run = saved_cur_run;
1602
1603   /* ... inserting the new tokens we collected.  */
1604   _cpp_push_token_context (pfile, NULL, toks, count);
1605 }
1606
1607 /* Handle the _Pragma operator.  Return 0 on error, 1 if ok.  */
1608 int
1609 _cpp_do__Pragma (cpp_reader *pfile)
1610 {
1611   const cpp_token *string = get__Pragma_string (pfile);
1612   pfile->directive_result.type = CPP_PADDING;
1613
1614   if (string)
1615     {
1616       destringize_and_run (pfile, &string->val.str);
1617       return 1;
1618     }
1619   cpp_error (pfile, CPP_DL_ERROR,
1620              "_Pragma takes a parenthesized string literal");
1621   return 0;
1622 }
1623
1624 /* Handle #ifdef.  */
1625 static void
1626 do_ifdef (cpp_reader *pfile)
1627 {
1628   int skip = 1;
1629
1630   if (! pfile->state.skipping)
1631     {
1632       const cpp_hashnode *node = lex_macro_node (pfile, false);
1633
1634       if (node)
1635         {
1636           skip = node->type != NT_MACRO;
1637           _cpp_mark_macro_used (node);
1638           check_eol (pfile);
1639         }
1640     }
1641
1642   push_conditional (pfile, skip, T_IFDEF, 0);
1643 }
1644
1645 /* Handle #ifndef.  */
1646 static void
1647 do_ifndef (cpp_reader *pfile)
1648 {
1649   int skip = 1;
1650   const cpp_hashnode *node = 0;
1651
1652   if (! pfile->state.skipping)
1653     {
1654       node = lex_macro_node (pfile, false);
1655
1656       if (node)
1657         {
1658           skip = node->type == NT_MACRO;
1659           _cpp_mark_macro_used (node);
1660           check_eol (pfile);
1661         }
1662     }
1663
1664   push_conditional (pfile, skip, T_IFNDEF, node);
1665 }
1666
1667 /* _cpp_parse_expr puts a macro in a "#if !defined ()" expression in
1668    pfile->mi_ind_cmacro so we can handle multiple-include
1669    optimizations.  If macro expansion occurs in the expression, we
1670    cannot treat it as a controlling conditional, since the expansion
1671    could change in the future.  That is handled by cpp_get_token.  */
1672 static void
1673 do_if (cpp_reader *pfile)
1674 {
1675   int skip = 1;
1676
1677   if (! pfile->state.skipping)
1678     skip = _cpp_parse_expr (pfile) == false;
1679
1680   push_conditional (pfile, skip, T_IF, pfile->mi_ind_cmacro);
1681 }
1682
1683 /* Flip skipping state if appropriate and continue without changing
1684    if_stack; this is so that the error message for missing #endif's
1685    etc. will point to the original #if.  */
1686 static void
1687 do_else (cpp_reader *pfile)
1688 {
1689   cpp_buffer *buffer = pfile->buffer;
1690   struct if_stack *ifs = buffer->if_stack;
1691
1692   if (ifs == NULL)
1693     cpp_error (pfile, CPP_DL_ERROR, "#else without #if");
1694   else
1695     {
1696       if (ifs->type == T_ELSE)
1697         {
1698           cpp_error (pfile, CPP_DL_ERROR, "#else after #else");
1699           cpp_error_with_line (pfile, CPP_DL_ERROR, ifs->line, 0,
1700                                "the conditional began here");
1701         }
1702       ifs->type = T_ELSE;
1703
1704       /* Skip any future (erroneous) #elses or #elifs.  */
1705       pfile->state.skipping = ifs->skip_elses;
1706       ifs->skip_elses = true;
1707
1708       /* Invalidate any controlling macro.  */
1709       ifs->mi_cmacro = 0;
1710
1711       /* Only check EOL if was not originally skipping.  */
1712       if (!ifs->was_skipping && CPP_OPTION (pfile, warn_endif_labels))
1713         check_eol (pfile);
1714     }
1715 }
1716
1717 /* Handle a #elif directive by not changing if_stack either.  See the
1718    comment above do_else.  */
1719 static void
1720 do_elif (cpp_reader *pfile)
1721 {
1722   cpp_buffer *buffer = pfile->buffer;
1723   struct if_stack *ifs = buffer->if_stack;
1724
1725   if (ifs == NULL)
1726     cpp_error (pfile, CPP_DL_ERROR, "#elif without #if");
1727   else
1728     {
1729       if (ifs->type == T_ELSE)
1730         {
1731           cpp_error (pfile, CPP_DL_ERROR, "#elif after #else");
1732           cpp_error_with_line (pfile, CPP_DL_ERROR, ifs->line, 0,
1733                                "the conditional began here");
1734         }
1735       ifs->type = T_ELIF;
1736
1737       /* Only evaluate this if we aren't skipping elses.  During
1738          evaluation, set skipping to false to get lexer warnings.  */
1739       if (ifs->skip_elses)
1740         pfile->state.skipping = 1;
1741       else
1742         {
1743           pfile->state.skipping = 0;
1744           pfile->state.skipping = ! _cpp_parse_expr (pfile);
1745           ifs->skip_elses = ! pfile->state.skipping;
1746         }
1747
1748       /* Invalidate any controlling macro.  */
1749       ifs->mi_cmacro = 0;
1750     }
1751 }
1752
1753 /* #endif pops the if stack and resets pfile->state.skipping.  */
1754 static void
1755 do_endif (cpp_reader *pfile)
1756 {
1757   cpp_buffer *buffer = pfile->buffer;
1758   struct if_stack *ifs = buffer->if_stack;
1759
1760   if (ifs == NULL)
1761     cpp_error (pfile, CPP_DL_ERROR, "#endif without #if");
1762   else
1763     {
1764       /* Only check EOL if was not originally skipping.  */
1765       if (!ifs->was_skipping && CPP_OPTION (pfile, warn_endif_labels))
1766         check_eol (pfile);
1767
1768       /* If potential control macro, we go back outside again.  */
1769       if (ifs->next == 0 && ifs->mi_cmacro)
1770         {
1771           pfile->mi_valid = true;
1772           pfile->mi_cmacro = ifs->mi_cmacro;
1773         }
1774
1775       buffer->if_stack = ifs->next;
1776       pfile->state.skipping = ifs->was_skipping;
1777       obstack_free (&pfile->buffer_ob, ifs);
1778     }
1779 }
1780
1781 /* Push an if_stack entry for a preprocessor conditional, and set
1782    pfile->state.skipping to SKIP.  If TYPE indicates the conditional
1783    is #if or #ifndef, CMACRO is a potentially controlling macro, and
1784    we need to check here that we are at the top of the file.  */
1785 static void
1786 push_conditional (cpp_reader *pfile, int skip, int type,
1787                   const cpp_hashnode *cmacro)
1788 {
1789   struct if_stack *ifs;
1790   cpp_buffer *buffer = pfile->buffer;
1791
1792   ifs = XOBNEW (&pfile->buffer_ob, struct if_stack);
1793   ifs->line = pfile->directive_line;
1794   ifs->next = buffer->if_stack;
1795   ifs->skip_elses = pfile->state.skipping || !skip;
1796   ifs->was_skipping = pfile->state.skipping;
1797   ifs->type = type;
1798   /* This condition is effectively a test for top-of-file.  */
1799   if (pfile->mi_valid && pfile->mi_cmacro == 0)
1800     ifs->mi_cmacro = cmacro;
1801   else
1802     ifs->mi_cmacro = 0;
1803
1804   pfile->state.skipping = skip;
1805   buffer->if_stack = ifs;
1806 }
1807
1808 /* Read the tokens of the answer into the macro pool, in a directive
1809    of type TYPE.  Only commit the memory if we intend it as permanent
1810    storage, i.e. the #assert case.  Returns 0 on success, and sets
1811    ANSWERP to point to the answer.  */
1812 static int
1813 parse_answer (cpp_reader *pfile, struct answer **answerp, int type)
1814 {
1815   const cpp_token *paren;
1816   struct answer *answer;
1817   unsigned int acount;
1818
1819   /* In a conditional, it is legal to not have an open paren.  We
1820      should save the following token in this case.  */
1821   paren = cpp_get_token (pfile);
1822
1823   /* If not a paren, see if we're OK.  */
1824   if (paren->type != CPP_OPEN_PAREN)
1825     {
1826       /* In a conditional no answer is a test for any answer.  It
1827          could be followed by any token.  */
1828       if (type == T_IF)
1829         {
1830           _cpp_backup_tokens (pfile, 1);
1831           return 0;
1832         }
1833
1834       /* #unassert with no answer is valid - it removes all answers.  */
1835       if (type == T_UNASSERT && paren->type == CPP_EOF)
1836         return 0;
1837
1838       cpp_error (pfile, CPP_DL_ERROR, "missing '(' after predicate");
1839       return 1;
1840     }
1841
1842   for (acount = 0;; acount++)
1843     {
1844       size_t room_needed;
1845       const cpp_token *token = cpp_get_token (pfile);
1846       cpp_token *dest;
1847
1848       if (token->type == CPP_CLOSE_PAREN)
1849         break;
1850
1851       if (token->type == CPP_EOF)
1852         {
1853           cpp_error (pfile, CPP_DL_ERROR, "missing ')' to complete answer");
1854           return 1;
1855         }
1856
1857       /* struct answer includes the space for one token.  */
1858       room_needed = (sizeof (struct answer) + acount * sizeof (cpp_token));
1859
1860       if (BUFF_ROOM (pfile->a_buff) < room_needed)
1861         _cpp_extend_buff (pfile, &pfile->a_buff, sizeof (struct answer));
1862
1863       dest = &((struct answer *) BUFF_FRONT (pfile->a_buff))->first[acount];
1864       *dest = *token;
1865
1866       /* Drop whitespace at start, for answer equivalence purposes.  */
1867       if (acount == 0)
1868         dest->flags &= ~PREV_WHITE;
1869     }
1870
1871   if (acount == 0)
1872     {
1873       cpp_error (pfile, CPP_DL_ERROR, "predicate's answer is empty");
1874       return 1;
1875     }
1876
1877   answer = (struct answer *) BUFF_FRONT (pfile->a_buff);
1878   answer->count = acount;
1879   answer->next = NULL;
1880   *answerp = answer;
1881
1882   return 0;
1883 }
1884
1885 /* Parses an assertion directive of type TYPE, returning a pointer to
1886    the hash node of the predicate, or 0 on error.  If an answer was
1887    supplied, it is placed in ANSWERP, otherwise it is set to 0.  */
1888 static cpp_hashnode *
1889 parse_assertion (cpp_reader *pfile, struct answer **answerp, int type)
1890 {
1891   cpp_hashnode *result = 0;
1892   const cpp_token *predicate;
1893
1894   /* We don't expand predicates or answers.  */
1895   pfile->state.prevent_expansion++;
1896
1897   *answerp = 0;
1898   predicate = cpp_get_token (pfile);
1899   if (predicate->type == CPP_EOF)
1900     cpp_error (pfile, CPP_DL_ERROR, "assertion without predicate");
1901   else if (predicate->type != CPP_NAME)
1902     cpp_error (pfile, CPP_DL_ERROR, "predicate must be an identifier");
1903   else if (parse_answer (pfile, answerp, type) == 0)
1904     {
1905       unsigned int len = NODE_LEN (predicate->val.node);
1906       unsigned char *sym = (unsigned char *) alloca (len + 1);
1907
1908       /* Prefix '#' to get it out of macro namespace.  */
1909       sym[0] = '#';
1910       memcpy (sym + 1, NODE_NAME (predicate->val.node), len);
1911       result = cpp_lookup (pfile, sym, len + 1);
1912     }
1913
1914   pfile->state.prevent_expansion--;
1915   return result;
1916 }
1917
1918 /* Returns a pointer to the pointer to CANDIDATE in the answer chain,
1919    or a pointer to NULL if the answer is not in the chain.  */
1920 static struct answer **
1921 find_answer (cpp_hashnode *node, const struct answer *candidate)
1922 {
1923   unsigned int i;
1924   struct answer **result;
1925
1926   for (result = &node->value.answers; *result; result = &(*result)->next)
1927     {
1928       struct answer *answer = *result;
1929
1930       if (answer->count == candidate->count)
1931         {
1932           for (i = 0; i < answer->count; i++)
1933             if (! _cpp_equiv_tokens (&answer->first[i], &candidate->first[i]))
1934               break;
1935
1936           if (i == answer->count)
1937             break;
1938         }
1939     }
1940
1941   return result;
1942 }
1943
1944 /* Test an assertion within a preprocessor conditional.  Returns
1945    nonzero on failure, zero on success.  On success, the result of
1946    the test is written into VALUE, otherwise the value 0.  */
1947 int
1948 _cpp_test_assertion (cpp_reader *pfile, unsigned int *value)
1949 {
1950   struct answer *answer;
1951   cpp_hashnode *node;
1952
1953   node = parse_assertion (pfile, &answer, T_IF);
1954
1955   /* For recovery, an erroneous assertion expression is handled as a
1956      failing assertion.  */
1957   *value = 0;
1958
1959   if (node)
1960     *value = (node->type == NT_ASSERTION &&
1961               (answer == 0 || *find_answer (node, answer) != 0));
1962   else if (pfile->cur_token[-1].type == CPP_EOF)
1963     _cpp_backup_tokens (pfile, 1);
1964
1965   /* We don't commit the memory for the answer - it's temporary only.  */
1966   return node == 0;
1967 }
1968
1969 /* Handle #assert.  */
1970 static void
1971 do_assert (cpp_reader *pfile)
1972 {
1973   struct answer *new_answer;
1974   cpp_hashnode *node;
1975
1976   node = parse_assertion (pfile, &new_answer, T_ASSERT);
1977   if (node)
1978     {
1979       size_t answer_size;
1980
1981       /* Place the new answer in the answer list.  First check there
1982          is not a duplicate.  */
1983       new_answer->next = 0;
1984       if (node->type == NT_ASSERTION)
1985         {
1986           if (*find_answer (node, new_answer))
1987             {
1988               cpp_error (pfile, CPP_DL_WARNING, "\"%s\" re-asserted",
1989                          NODE_NAME (node) + 1);
1990               return;
1991             }
1992           new_answer->next = node->value.answers;
1993         }
1994
1995       answer_size = sizeof (struct answer) + ((new_answer->count - 1)
1996                                               * sizeof (cpp_token));
1997       /* Commit or allocate storage for the object.  */
1998       if (pfile->hash_table->alloc_subobject)
1999         {
2000           struct answer *temp_answer = new_answer;
2001           new_answer = (struct answer *) pfile->hash_table->alloc_subobject
2002             (answer_size);
2003           memcpy (new_answer, temp_answer, answer_size);
2004         }
2005       else
2006         BUFF_FRONT (pfile->a_buff) += answer_size;
2007
2008       node->type = NT_ASSERTION;
2009       node->value.answers = new_answer;
2010       check_eol (pfile);
2011     }
2012 }
2013
2014 /* Handle #unassert.  */
2015 static void
2016 do_unassert (cpp_reader *pfile)
2017 {
2018   cpp_hashnode *node;
2019   struct answer *answer;
2020
2021   node = parse_assertion (pfile, &answer, T_UNASSERT);
2022   /* It isn't an error to #unassert something that isn't asserted.  */
2023   if (node && node->type == NT_ASSERTION)
2024     {
2025       if (answer)
2026         {
2027           struct answer **p = find_answer (node, answer), *temp;
2028
2029           /* Remove the answer from the list.  */
2030           temp = *p;
2031           if (temp)
2032             *p = temp->next;
2033
2034           /* Did we free the last answer?  */
2035           if (node->value.answers == 0)
2036             node->type = NT_VOID;
2037
2038           check_eol (pfile);
2039         }
2040       else
2041         _cpp_free_definition (node);
2042     }
2043
2044   /* We don't commit the memory for the answer - it's temporary only.  */
2045 }
2046
2047 /* These are for -D, -U, -A.  */
2048
2049 /* Process the string STR as if it appeared as the body of a #define.
2050    If STR is just an identifier, define it with value 1.
2051    If STR has anything after the identifier, then it should
2052    be identifier=definition.  */
2053 void
2054 cpp_define (cpp_reader *pfile, const char *str)
2055 {
2056   char *buf, *p;
2057   size_t count;
2058
2059   /* Copy the entire option so we can modify it.
2060      Change the first "=" in the string to a space.  If there is none,
2061      tack " 1" on the end.  */
2062
2063   count = strlen (str);
2064   buf = (char *) alloca (count + 3);
2065   memcpy (buf, str, count);
2066
2067   p = strchr (str, '=');
2068   if (p)
2069     buf[p - str] = ' ';
2070   else
2071     {
2072       buf[count++] = ' ';
2073       buf[count++] = '1';
2074     }
2075   buf[count] = '\n';
2076
2077   run_directive (pfile, T_DEFINE, buf, count);
2078 }
2079
2080 /* Slight variant of the above for use by initialize_builtins.  */
2081 void
2082 _cpp_define_builtin (cpp_reader *pfile, const char *str)
2083 {
2084   size_t len = strlen (str);
2085   char *buf = (char *) alloca (len + 1);
2086   memcpy (buf, str, len);
2087   buf[len] = '\n';
2088   run_directive (pfile, T_DEFINE, buf, len);
2089 }
2090
2091 /* Process MACRO as if it appeared as the body of an #undef.  */
2092 void
2093 cpp_undef (cpp_reader *pfile, const char *macro)
2094 {
2095   size_t len = strlen (macro);
2096   char *buf = (char *) alloca (len + 1);
2097   memcpy (buf, macro, len);
2098   buf[len] = '\n';
2099   run_directive (pfile, T_UNDEF, buf, len);
2100 }
2101
2102 /* Like lex_macro_node, but read the input from STR.  */
2103 static cpp_hashnode *
2104 lex_macro_node_from_str (cpp_reader *pfile, const char *str)
2105 {
2106   size_t len = strlen (str);
2107   uchar *buf = (uchar *) alloca (len + 1);
2108   cpp_hashnode *node;
2109
2110   memcpy (buf, str, len);
2111   buf[len] = '\n';
2112   cpp_push_buffer (pfile, buf, len, true);
2113   node = lex_macro_node (pfile, true);
2114   _cpp_pop_buffer (pfile);
2115
2116   return node;
2117 }
2118
2119 /* If STR is a defined macro, return its definition node, else return NULL.  */
2120 cpp_macro *
2121 cpp_push_definition (cpp_reader *pfile, const char *str)
2122 {
2123   cpp_hashnode *node = lex_macro_node_from_str (pfile, str);
2124   if (node && node->type == NT_MACRO)
2125     return node->value.macro;
2126   else
2127     return NULL;
2128 }
2129
2130 /* Replace a previous definition DFN of the macro STR.  If DFN is NULL,
2131    then the macro should be undefined.  */
2132 void
2133 cpp_pop_definition (cpp_reader *pfile, const char *str, cpp_macro *dfn)
2134 {
2135   cpp_hashnode *node = lex_macro_node_from_str (pfile, str);
2136   if (node == NULL)
2137     return;
2138
2139   if (node->type == NT_MACRO)
2140     {
2141       if (pfile->cb.undef)
2142         pfile->cb.undef (pfile, pfile->directive_line, node);
2143       if (CPP_OPTION (pfile, warn_unused_macros))
2144         _cpp_warn_if_unused_macro (pfile, node, NULL);
2145     }
2146   if (node->type != NT_VOID)
2147     _cpp_free_definition (node);
2148
2149   if (dfn)
2150     {
2151       node->type = NT_MACRO;
2152       node->value.macro = dfn;
2153       if (! ustrncmp (NODE_NAME (node), DSC ("__STDC_")))
2154         node->flags |= NODE_WARN;
2155
2156       if (pfile->cb.define)
2157         pfile->cb.define (pfile, pfile->directive_line, node);
2158     }
2159 }
2160
2161 /* Process the string STR as if it appeared as the body of a #assert.  */
2162 void
2163 cpp_assert (cpp_reader *pfile, const char *str)
2164 {
2165   handle_assertion (pfile, str, T_ASSERT);
2166 }
2167
2168 /* Process STR as if it appeared as the body of an #unassert.  */
2169 void
2170 cpp_unassert (cpp_reader *pfile, const char *str)
2171 {
2172   handle_assertion (pfile, str, T_UNASSERT);
2173 }
2174
2175 /* Common code for cpp_assert (-A) and cpp_unassert (-A-).  */
2176 static void
2177 handle_assertion (cpp_reader *pfile, const char *str, int type)
2178 {
2179   size_t count = strlen (str);
2180   const char *p = strchr (str, '=');
2181
2182   /* Copy the entire option so we can modify it.  Change the first
2183      "=" in the string to a '(', and tack a ')' on the end.  */
2184   char *buf = (char *) alloca (count + 2);
2185
2186   memcpy (buf, str, count);
2187   if (p)
2188     {
2189       buf[p - str] = '(';
2190       buf[count++] = ')';
2191     }
2192   buf[count] = '\n';
2193   str = buf;
2194
2195   run_directive (pfile, type, str, count);
2196 }
2197
2198 /* The number of errors for a given reader.  */
2199 unsigned int
2200 cpp_errors (cpp_reader *pfile)
2201 {
2202   return pfile->errors;
2203 }
2204
2205 /* The options structure.  */
2206 cpp_options *
2207 cpp_get_options (cpp_reader *pfile)
2208 {
2209   return &pfile->opts;
2210 }
2211
2212 /* The callbacks structure.  */
2213 cpp_callbacks *
2214 cpp_get_callbacks (cpp_reader *pfile)
2215 {
2216   return &pfile->cb;
2217 }
2218
2219 /* Copy the given callbacks structure to our own.  */
2220 void
2221 cpp_set_callbacks (cpp_reader *pfile, cpp_callbacks *cb)
2222 {
2223   pfile->cb = *cb;
2224 }
2225
2226 /* The dependencies structure.  (Creates one if it hasn't already been.)  */
2227 struct deps *
2228 cpp_get_deps (cpp_reader *pfile)
2229 {
2230   if (!pfile->deps)
2231     pfile->deps = deps_init ();
2232   return pfile->deps;
2233 }
2234
2235 /* Push a new buffer on the buffer stack.  Returns the new buffer; it
2236    doesn't fail.  It does not generate a file change call back; that
2237    is the responsibility of the caller.  */
2238 cpp_buffer *
2239 cpp_push_buffer (cpp_reader *pfile, const uchar *buffer, size_t len,
2240                  int from_stage3)
2241 {
2242   cpp_buffer *new_buffer = XOBNEW (&pfile->buffer_ob, cpp_buffer);
2243
2244   /* Clears, amongst other things, if_stack and mi_cmacro.  */
2245   memset (new_buffer, 0, sizeof (cpp_buffer));
2246
2247   new_buffer->next_line = new_buffer->buf = buffer;
2248   new_buffer->rlimit = buffer + len;
2249   new_buffer->from_stage3 = from_stage3;
2250   new_buffer->prev = pfile->buffer;
2251   new_buffer->need_line = true;
2252
2253   pfile->buffer = new_buffer;
2254
2255   return new_buffer;
2256 }
2257
2258 /* Pops a single buffer, with a file change call-back if appropriate.
2259    Then pushes the next -include file, if any remain.  */
2260 void
2261 _cpp_pop_buffer (cpp_reader *pfile)
2262 {
2263   cpp_buffer *buffer = pfile->buffer;
2264   struct _cpp_file *inc = buffer->file;
2265   struct if_stack *ifs;
2266
2267   /* Walk back up the conditional stack till we reach its level at
2268      entry to this file, issuing error messages.  */
2269   for (ifs = buffer->if_stack; ifs; ifs = ifs->next)
2270     cpp_error_with_line (pfile, CPP_DL_ERROR, ifs->line, 0,
2271                          "unterminated #%s", dtable[ifs->type].name);
2272
2273   /* In case of a missing #endif.  */
2274   pfile->state.skipping = 0;
2275
2276   /* _cpp_do_file_change expects pfile->buffer to be the new one.  */
2277   pfile->buffer = buffer->prev;
2278
2279   free (buffer->notes);
2280
2281   /* Free the buffer object now; we may want to push a new buffer
2282      in _cpp_push_next_include_file.  */
2283   obstack_free (&pfile->buffer_ob, buffer);
2284
2285   if (inc)
2286     {
2287       _cpp_pop_file_buffer (pfile, inc);
2288
2289       _cpp_do_file_change (pfile, LC_LEAVE, 0, 0, 0);
2290     }
2291 }
2292
2293 /* Enter all recognized directives in the hash table.  */
2294 void
2295 _cpp_init_directives (cpp_reader *pfile)
2296 {
2297   unsigned int i;
2298   cpp_hashnode *node;
2299
2300   for (i = 0; i < (unsigned int) N_DIRECTIVES; i++)
2301     {
2302       node = cpp_lookup (pfile, dtable[i].name, dtable[i].length);
2303       node->is_directive = 1;
2304       node->directive_index = i;
2305     }
2306 }