gcc/gengtype-parse.c

   1 /* Process source files and output type information.
   2    Copyright (C) 2006, 2007, 2010 Free Software Foundation, Inc.
   3
   4    This file is part of GCC.
   5
   6    GCC is free software; you can redistribute it and/or modify it under
   7    the terms of the GNU General Public License as published by the Free
   8    Software Foundation; either version 3, or (at your option) any later
   9    version.
  10
  11    GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  12    WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13    FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14    for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with GCC; see the file COPYING3.  If not see
  18    <http://www.gnu.org/licenses/>.  */
  19
  20 #include "bconfig.h"
  21 #include "system.h"
  22 #include "gengtype.h"
  23
  24 /* This is a simple recursive-descent parser which understands a subset of
  25    the C type grammar.
  26
  27    Rule functions are suffixed _seq if they scan a sequence of items;
  28    _opt if they may consume zero tokens; _seqopt if both are true.  The
  29    "consume_" prefix indicates that a sequence of tokens is parsed for
  30    syntactic correctness and then thrown away.  */
  31
  32 /* Simple one-token lookahead mechanism.  */
  33
  34 struct token
  35 {
  36   const char *value;
  37   int code;
  38   bool valid;
  39 };
  40 static struct token T;
  41
  42 /* Retrieve the code of the current token; if there is no current token,
  43    get the next one from the lexer.  */
  44 static inline int
  45 token (void)
  46 {
  47   if (!T.valid)
  48     {
  49       T.code = yylex (&T.value);
  50       T.valid = true;
  51     }
  52   return T.code;
  53 }
  54
  55 /* Retrieve the value of the current token (if any) and mark it consumed.
  56    The next call to token() will get another token from the lexer.  */
  57 static inline const char *
  58 advance (void)
  59 {
  60   T.valid = false;
  61   return T.value;
  62 }
  63
  64 /* Diagnostics.  */
  65
  66 /* This array is indexed by the token code minus CHAR_TOKEN_OFFSET.  */
  67 static const char *const token_names[] = {
  68   "GTY",
  69   "typedef",
  70   "extern",
  71   "static",
  72   "union",
  73   "struct",
  74   "enum",
  75   "VEC",
  76   "DEF_VEC_[OP]",
  77   "DEF_VEC_I",
  78   "DEF_VEC_ALLOC_[IOP]",
  79   "...",
  80   "ptr_alias",
  81   "nested_ptr",
  82   "a param<N>_is option",
  83   "a number",
  84   "a scalar type",
  85   "an identifier",
  86   "a string constant",
  87   "a character constant",
  88   "an array declarator",
  89 };
  90
  91 /* This array is indexed by token code minus FIRST_TOKEN_WITH_VALUE.  */
  92 static const char *const token_value_format[] = {
  93   "%s",
  94   "'%s'",
  95   "'%s'",
  96   "'%s'",
  97   "'\"%s\"'",
  98   "\"'%s'\"",
  99   "'[%s]'",
 100 };
 101
 102 /* Produce a printable representation for a token defined by CODE and
 103    VALUE.  This sometimes returns pointers into malloc memory and
 104    sometimes not, therefore it is unsafe to free the pointer it
 105    returns, so that memory is leaked.  This does not matter, as this
 106    function is only used for diagnostics, and in a successful run of
 107    the program there will be none.  */
 108 static const char *
 109 print_token (int code, const char *value)
 110 {
 111   if (code < CHAR_TOKEN_OFFSET)
 112     return xasprintf ("'%c'", code);
 113   else if (code < FIRST_TOKEN_WITH_VALUE)
 114     return xasprintf ("'%s'", token_names[code - CHAR_TOKEN_OFFSET]);
 115   else if (!value)
 116     return token_names[code - CHAR_TOKEN_OFFSET];       /* don't quote these */
 117   else
 118     return xasprintf (token_value_format[code - FIRST_TOKEN_WITH_VALUE],
 119                       value);
 120 }
 121
 122 /* Convenience wrapper around print_token which produces the printable
 123    representation of the current token.  */
 124 static inline const char *
 125 print_cur_token (void)
 126 {
 127   return print_token (T.code, T.value);
 128 }
 129
 130 /* Report a parse error on the current line, with diagnostic MSG.
 131    Behaves as standard printf with respect to additional arguments and
 132    format escapes.  */
 133 static void ATTRIBUTE_PRINTF_1
 134 parse_error (const char *msg, ...)
 135 {
 136   va_list ap;
 137
 138   fprintf (stderr, "%s:%d: parse error: ",
 139            get_input_file_name (lexer_line.file), lexer_line.line);
 140
 141   va_start (ap, msg);
 142   vfprintf (stderr, msg, ap);
 143   va_end (ap);
 144
 145   fputc ('\n', stderr);
 146
 147   hit_error = true;
 148 }
 149
 150 /* If the next token does not have code T, report a parse error; otherwise
 151    return the token's value.  */
 152 static const char *
 153 require (int t)
 154 {
 155   int u = token ();
 156   const char *v = advance ();
 157   if (u != t)
 158     {
 159       parse_error ("expected %s, have %s",
 160                    print_token (t, 0), print_token (u, v));
 161       return 0;
 162     }
 163   return v;
 164 }
 165
 166 /* If the next token does not have one of the codes T1 or T2, report a
 167    parse error; otherwise return the token's value.  */
 168 static const char *
 169 require2 (int t1, int t2)
 170 {
 171   int u = token ();
 172   const char *v = advance ();
 173   if (u != t1 && u != t2)
 174     {
 175       parse_error ("expected %s or %s, have %s",
 176                    print_token (t1, 0), print_token (t2, 0),
 177                    print_token (u, v));
 178       return 0;
 179     }
 180   return v;
 181 }
 182
 183 /* Near-terminals.  */
 184
 185 /* C-style string constant concatenation: STRING+
 186    Bare STRING should appear nowhere else in this file.  */
 187 static const char *
 188 string_seq (void)
 189 {
 190   const char *s1, *s2;
 191   size_t l1, l2;
 192   char *buf;
 193
 194   s1 = require (STRING);
 195   if (s1 == 0)
 196     return "";
 197   while (token () == STRING)
 198     {
 199       s2 = advance ();
 200
 201       l1 = strlen (s1);
 202       l2 = strlen (s2);
 203       buf = XRESIZEVEC (char, CONST_CAST (char *, s1), l1 + l2 + 1);
 204       memcpy (buf + l1, s2, l2 + 1);
 205       XDELETE (CONST_CAST (char *, s2));
 206       s1 = buf;
 207     }
 208   return s1;
 209 }
 210
 211 /* typedef_name: either an ID, or VEC(x,y) which is translated to VEC_x_y.
 212    Use only where VEC(x,y) is legitimate, i.e. in positions where a
 213    typedef name may appear.  */
 214 static const char *
 215 typedef_name (void)
 216 {
 217   if (token () == VEC_TOKEN)
 218     {
 219       const char *c1, *c2, *r;
 220       advance ();
 221       require ('(');
 222       c1 = require2 (ID, SCALAR);
 223       require (',');
 224       c2 = require (ID);
 225       require (')');
 226       r = concat ("VEC_", c1, "_", c2, (char *) 0);
 227       free (CONST_CAST (char *, c1));
 228       free (CONST_CAST (char *, c2));
 229       return r;
 230     }
 231   else
 232     return require (ID);
 233 }
 234
 235 /* Absorb a sequence of tokens delimited by balanced ()[]{}.  */
 236 static void
 237 consume_balanced (int opener, int closer)
 238 {
 239   require (opener);
 240   for (;;)
 241     switch (token ())
 242       {
 243       default:
 244         advance ();
 245         break;
 246       case '(':
 247         consume_balanced ('(', ')');
 248         break;
 249       case '[':
 250         consume_balanced ('[', ']');
 251         break;
 252       case '{':
 253         consume_balanced ('{', '}');
 254         break;
 255
 256       case '}':
 257       case ']':
 258       case ')':
 259         if (token () != closer)
 260           parse_error ("unbalanced delimiters - expected '%c', have '%c'",
 261                        closer, token ());
 262       advance ();
 263       return;
 264
 265       case EOF_TOKEN:
 266         parse_error ("unexpected end of file within %c%c-delimited construct",
 267                      opener, closer);
 268         return;
 269       }
 270 }
 271
 272 /* Absorb a sequence of tokens, possibly including ()[]{}-delimited
 273    expressions, until we encounter a semicolon outside any such
 274    delimiters; absorb that too.  If IMMEDIATE is true, it is an error
 275    if the semicolon is not the first token encountered.  */
 276 static void
 277 consume_until_semi (bool immediate)
 278 {
 279   if (immediate && token () != ';')
 280     require (';');
 281   for (;;)
 282     switch (token ())
 283       {
 284       case ';':
 285         advance ();
 286         return;
 287       default:
 288         advance ();
 289         break;
 290
 291       case '(':
 292         consume_balanced ('(', ')');
 293         break;
 294       case '[':
 295         consume_balanced ('[', ']');
 296         break;
 297       case '{':
 298         consume_balanced ('{', '}');
 299         break;
 300
 301       case '}':
 302       case ']':
 303       case ')':
 304         parse_error ("unmatched '%c' while scanning for ';'", token ());
 305       return;
 306
 307       case EOF_TOKEN:
 308         parse_error ("unexpected end of file while scanning for ';'");
 309         return;
 310       }
 311 }
 312
 313 /* Absorb a sequence of tokens, possibly including ()[]{}-delimited
 314    expressions, until we encounter a comma or semicolon outside any
 315    such delimiters; absorb that too.  If IMMEDIATE is true, it is an
 316    error if the comma or semicolon is not the first token encountered.
 317    Returns true if the loop ended with a comma.  */
 318 static bool
 319 consume_until_comma_or_semi (bool immediate)
 320 {
 321   if (immediate && token () != ',' && token () != ';')
 322     require2 (',', ';');
 323   for (;;)
 324     switch (token ())
 325       {
 326       case ',':
 327         advance ();
 328         return true;
 329       case ';':
 330         advance ();
 331         return false;
 332       default:
 333         advance ();
 334         break;
 335
 336       case '(':
 337         consume_balanced ('(', ')');
 338         break;
 339       case '[':
 340         consume_balanced ('[', ']');
 341         break;
 342       case '{':
 343         consume_balanced ('{', '}');
 344         break;
 345
 346       case '}':
 347       case ']':
 348       case ')':
 349         parse_error ("unmatched '%s' while scanning for ',' or ';'",
 350                      print_cur_token ());
 351       return false;
 352
 353       case EOF_TOKEN:
 354         parse_error ("unexpected end of file while scanning for ',' or ';'");
 355         return false;
 356       }
 357 }
 358 \f
 359
 360 /* GTY(()) option handling.  */
 361 static type_p type (options_p *optsp, bool nested);
 362
 363 /* Optional parenthesized string: ('(' string_seq ')')? */
 364 static options_p
 365 str_optvalue_opt (options_p prev)
 366 {
 367   const char *name = advance ();
 368   const char *value = "";
 369   if (token () == '(')
 370     {
 371       advance ();
 372       value = string_seq ();
 373       require (')');
 374     }
 375   return create_string_option (prev, name, value);
 376 }
 377
 378 /* absdecl: type '*'*
 379    -- a vague approximation to what the C standard calls an abstract
 380    declarator.  The only kinds that are actually used are those that
 381    are just a bare type and those that have trailing pointer-stars.
 382    Further kinds should be implemented if and when they become
 383    necessary.  Used only within GTY(()) option values, therefore
 384    further GTY(()) tags within the type are invalid.  Note that the
 385    return value has already been run through adjust_field_type.  */
 386 static type_p
 387 absdecl (void)
 388 {
 389   type_p ty;
 390   options_p opts;
 391
 392   ty = type (&opts, true);
 393   while (token () == '*')
 394     {
 395       ty = create_pointer (ty);
 396       advance ();
 397     }
 398
 399   if (opts)
 400     parse_error ("nested GTY(()) options are invalid");
 401
 402   return adjust_field_type (ty, 0);
 403 }
 404
 405 /* Type-option: '(' absdecl ')' */
 406 static options_p
 407 type_optvalue (options_p prev, const char *name)
 408 {
 409   type_p ty;
 410   require ('(');
 411   ty = absdecl ();
 412   require (')');
 413   return create_type_option (prev, name, ty);
 414 }
 415
 416 /* Nested pointer data: '(' type '*'* ',' string_seq ',' string_seq ')' */
 417 static options_p
 418 nestedptr_optvalue (options_p prev)
 419 {
 420   type_p ty;
 421   const char *from, *to;
 422
 423   require ('(');
 424   ty = absdecl ();
 425   require (',');
 426   to = string_seq ();
 427   require (',');
 428   from = string_seq ();
 429   require (')');
 430
 431   return create_nested_ptr_option (prev, ty, to, from);
 432 }
 433
 434 /* One GTY(()) option:
 435    ID str_optvalue_opt
 436    | PTR_ALIAS type_optvalue
 437    | PARAM_IS type_optvalue
 438    | NESTED_PTR nestedptr_optvalue
 439 */
 440 static options_p
 441 option (options_p prev)
 442 {
 443   switch (token ())
 444     {
 445     case ID:
 446       return str_optvalue_opt (prev);
 447
 448     case PTR_ALIAS:
 449       advance ();
 450       return type_optvalue (prev, "ptr_alias");
 451
 452     case PARAM_IS:
 453       return type_optvalue (prev, advance ());
 454
 455     case NESTED_PTR:
 456       advance ();
 457       return nestedptr_optvalue (prev);
 458
 459     default:
 460       parse_error ("expected an option keyword, have %s", print_cur_token ());
 461       advance ();
 462       return create_string_option (prev, "", "");
 463     }
 464 }
 465
 466 /* One comma-separated list of options.  */
 467 static options_p
 468 option_seq (void)
 469 {
 470   options_p o;
 471
 472   o = option (0);
 473   while (token () == ',')
 474     {
 475       advance ();
 476       o = option (o);
 477     }
 478   return o;
 479 }
 480
 481 /* GTY marker: 'GTY' '(' '(' option_seq? ')' ')' */
 482 static options_p
 483 gtymarker (void)
 484 {
 485   options_p result = 0;
 486   require (GTY_TOKEN);
 487   require ('(');
 488   require ('(');
 489   if (token () != ')')
 490     result = option_seq ();
 491   require (')');
 492   require (')');
 493   return result;
 494 }
 495
 496 /* Optional GTY marker.  */
 497 static options_p
 498 gtymarker_opt (void)
 499 {
 500   if (token () != GTY_TOKEN)
 501     return 0;
 502   return gtymarker ();
 503 }
 504 \f
 505 /* Declarators. The logic here is largely lifted from c-parser.c.
 506    Note that we do not have to process abstract declarators, which can
 507    appear only in parameter type lists or casts (but see absdecl,
 508    above).  Also, type qualifiers are thrown out in gengtype-lex.l so
 509    we don't have to do it.  */
 510
 511 /* array_and_function_declarators_opt:
 512    \epsilon
 513    array_and_function_declarators_opt ARRAY
 514    array_and_function_declarators_opt '(' ... ')'
 515
 516    where '...' indicates stuff we ignore except insofar as grouping
 517    symbols ()[]{} must balance.
 518
 519    Subroutine of direct_declarator - do not use elsewhere. */
 520
 521 static type_p
 522 array_and_function_declarators_opt (type_p ty)
 523 {
 524   if (token () == ARRAY)
 525     {
 526       const char *array = advance ();
 527       return create_array (array_and_function_declarators_opt (ty), array);
 528     }
 529   else if (token () == '(')
 530     {
 531       /* We don't need exact types for functions.  */
 532       consume_balanced ('(', ')');
 533       array_and_function_declarators_opt (ty);
 534       return create_scalar_type ("function type");
 535     }
 536   else
 537     return ty;
 538 }
 539
 540 static type_p inner_declarator (type_p, const char **, options_p *);
 541
 542 /* direct_declarator:
 543    '(' inner_declarator ')'
 544    gtymarker_opt ID array_and_function_declarators_opt
 545
 546    Subroutine of declarator, mutually recursive with inner_declarator;
 547    do not use elsewhere.  */
 548 static type_p
 549 direct_declarator (type_p ty, const char **namep, options_p *optsp)
 550 {
 551   /* The first token in a direct-declarator must be an ID, a
 552      GTY marker, or an open parenthesis.  */
 553   switch (token ())
 554     {
 555     case GTY_TOKEN:
 556       *optsp = gtymarker ();
 557       /* fall through */
 558     case ID:
 559       *namep = require (ID);
 560       break;
 561
 562     case '(':
 563       advance ();
 564       ty = inner_declarator (ty, namep, optsp);
 565       require (')');
 566       break;
 567
 568     default:
 569       parse_error ("expected '(', 'GTY', or an identifier, have %s",
 570                    print_cur_token ());
 571       /* Do _not_ advance if what we have is a close squiggle brace, as
 572          we will get much better error recovery that way.  */
 573       if (token () != '}')
 574         advance ();
 575       return 0;
 576     }
 577   return array_and_function_declarators_opt (ty);
 578 }
 579
 580 /* The difference between inner_declarator and declarator is in the
 581    handling of stars.  Consider this declaration:
 582
 583    char * (*pfc) (void)
 584
 585    It declares a pointer to a function that takes no arguments and
 586    returns a char*.  To construct the correct type for this
 587    declaration, the star outside the parentheses must be processed
 588    _before_ the function type, the star inside the parentheses must
 589    be processed _after_ the function type.  To accomplish this,
 590    declarator() creates pointers before recursing (it is actually
 591    coded as a while loop), whereas inner_declarator() recurses before
 592    creating pointers.  */
 593
 594 /* inner_declarator:
 595    '*' inner_declarator
 596    direct_declarator
 597
 598    Mutually recursive subroutine of direct_declarator; do not use
 599    elsewhere.  */
 600
 601 static type_p
 602 inner_declarator (type_p ty, const char **namep, options_p *optsp)
 603 {
 604   if (token () == '*')
 605     {
 606       type_p inner;
 607       advance ();
 608       inner = inner_declarator (ty, namep, optsp);
 609       if (inner == 0)
 610         return 0;
 611       else
 612         return create_pointer (ty);
 613     }
 614   else
 615     return direct_declarator (ty, namep, optsp);
 616 }
 617
 618 /* declarator: '*'+ direct_declarator
 619
 620    This is the sole public interface to this part of the grammar.
 621    Arguments are the type known so far, a pointer to where the name
 622    may be stored, and a pointer to where GTY options may be stored.
 623    Returns the final type. */
 624
 625 static type_p
 626 declarator (type_p ty, const char **namep, options_p *optsp)
 627 {
 628   *namep = 0;
 629   *optsp = 0;
 630   while (token () == '*')
 631     {
 632       advance ();
 633       ty = create_pointer (ty);
 634     }
 635   return direct_declarator (ty, namep, optsp);
 636 }
 637 \f
 638 /* Types and declarations.  */
 639
 640 /* Structure field(s) declaration:
 641    (
 642    type bitfield ';'
 643    | type declarator bitfield? ( ',' declarator bitfield? )+ ';'
 644    )+
 645
 646    Knows that such declarations must end with a close brace (or,
 647    erroneously, at EOF).
 648 */
 649 static pair_p
 650 struct_field_seq (void)
 651 {
 652   pair_p f = 0;
 653   type_p ty, dty;
 654   options_p opts, dopts;
 655   const char *name;
 656   bool another;
 657
 658   do
 659     {
 660       ty = type (&opts, true);
 661       /* Another piece of the IFCVT_EXTRA_FIELDS special case, see type().  */
 662       if (!ty && token () == '}')
 663         break;
 664
 665       if (!ty || token () == ':')
 666         {
 667           consume_until_semi (false);
 668           continue;
 669         }
 670
 671       do
 672         {
 673           dty = declarator (ty, &name, &dopts);
 674           /* There could be any number of weird things after the declarator,
 675              notably bitfield declarations and __attribute__s.  If this
 676              function returns true, the last thing was a comma, so we have
 677              more than one declarator paired with the current type.  */
 678           another = consume_until_comma_or_semi (false);
 679
 680           if (!dty)
 681             continue;
 682
 683           if (opts && dopts)
 684             parse_error ("two GTY(()) options for field %s", name);
 685           if (opts && !dopts)
 686             dopts = opts;
 687
 688           f = create_field_at (f, dty, name, dopts, &lexer_line);
 689         }
 690       while (another);
 691     }
 692   while (token () != '}' && token () != EOF_TOKEN);
 693   return nreverse_pairs (f);
 694 }
 695
 696 /* This is called type(), but what it parses (sort of) is what C calls
 697    declaration-specifiers and specifier-qualifier-list:
 698
 699    SCALAR
 700    | ID     // typedef
 701    | (STRUCT|UNION) ID? gtymarker? ( '{' gtymarker? struct_field_seq '}' )?
 702    | ENUM ID ( '{' ... '}' )?
 703
 704    Returns a partial type; under some conditions (notably
 705    "struct foo GTY((...)) thing;") it may write an options
 706    structure to *OPTSP.
 707 */
 708 static type_p
 709 type (options_p *optsp, bool nested)
 710 {
 711   const char *s;
 712   *optsp = 0;
 713   switch (token ())
 714     {
 715     case SCALAR:
 716       s = advance ();
 717       return create_scalar_type (s);
 718
 719     case ID:
 720     case VEC_TOKEN:
 721       s = typedef_name ();
 722       return resolve_typedef (s, &lexer_line);
 723
 724     case STRUCT:
 725     case UNION:
 726       {
 727         options_p opts = 0;
 728         /* GTY annotations follow attribute syntax
 729            GTY_BEFORE_ID is for union/struct declarations
 730            GTY_AFTER_ID is for variable declarations.  */
 731         enum
 732         {
 733           NO_GTY,
 734           GTY_BEFORE_ID,
 735           GTY_AFTER_ID
 736         } is_gty = NO_GTY;
 737         bool is_union = (token () == UNION);
 738         advance ();
 739
 740         /* Top-level structures that are not explicitly tagged GTY(())
 741            are treated as mere forward declarations.  This is because
 742            there are a lot of structures that we don't need to know
 743            about, and some of those have weird macro stuff in them
 744            that we can't handle.  */
 745         if (nested || token () == GTY_TOKEN)
 746           {
 747             is_gty = GTY_BEFORE_ID;
 748             opts = gtymarker_opt ();
 749           }
 750
 751         if (token () == ID)
 752           s = advance ();
 753         else
 754           s = xasprintf ("anonymous:%s:%d",
 755                          get_input_file_name (lexer_line.file),
 756                          lexer_line.line);
 757
 758         /* Unfortunately above GTY_TOKEN check does not capture the
 759            typedef struct_type GTY case.  */
 760         if (token () == GTY_TOKEN)
 761           {
 762             is_gty = GTY_AFTER_ID;
 763             opts = gtymarker_opt ();
 764           }
 765
 766         if (is_gty)
 767           {
 768             if (token () == '{')
 769               {
 770                 pair_p fields;
 771
 772                 if (is_gty == GTY_AFTER_ID)
 773                   parse_error ("GTY must be specified before identifier");
 774
 775                 advance ();
 776                 fields = struct_field_seq ();
 777                 require ('}');
 778                 return new_structure (s, is_union, &lexer_line, fields, opts);
 779               }
 780           }
 781         else if (token () == '{')
 782           consume_balanced ('{', '}');
 783         if (opts)
 784           *optsp = opts;
 785         return find_structure (s, is_union);
 786       }
 787
 788     case ENUM:
 789       advance ();
 790       if (token () == ID)
 791         s = advance ();
 792       else
 793         s = xasprintf ("anonymous:%s:%d",
 794                        get_input_file_name (lexer_line.file),
 795                        lexer_line.line);
 796
 797       if (token () == '{')
 798         consume_balanced ('{', '}');
 799       return create_scalar_type (s);
 800
 801     default:
 802       parse_error ("expected a type specifier, have %s", print_cur_token ());
 803       advance ();
 804       return create_scalar_type ("erroneous type");
 805     }
 806 }
 807 \f
 808 /* Top level constructs.  */
 809
 810 /* Dispatch declarations beginning with 'typedef'.  */
 811
 812 static void
 813 typedef_decl (void)
 814 {
 815   type_p ty, dty;
 816   const char *name;
 817   options_p opts;
 818   bool another;
 819
 820   gcc_assert (token () == TYPEDEF);
 821   advance ();
 822
 823   ty = type (&opts, false);
 824   if (!ty)
 825     return;
 826   if (opts)
 827     parse_error ("GTY((...)) cannot be applied to a typedef");
 828   do
 829     {
 830       dty = declarator (ty, &name, &opts);
 831       if (opts)
 832         parse_error ("GTY((...)) cannot be applied to a typedef");
 833
 834       /* Yet another place where we could have junk (notably attributes)
 835          after the declarator.  */
 836       another = consume_until_comma_or_semi (false);
 837       if (dty)
 838         do_typedef (name, dty, &lexer_line);
 839     }
 840   while (another);
 841 }
 842
 843 /* Structure definition: type() does all the work.  */
 844
 845 static void
 846 struct_or_union (void)
 847 {
 848   options_p dummy;
 849   type (&dummy, false);
 850   /* There may be junk after the type: notably, we cannot currently
 851      distinguish 'struct foo *function(prototype);' from 'struct foo;'
 852      ...  we could call declarator(), but it's a waste of time at
 853      present.  Instead, just eat whatever token is currently lookahead
 854      and go back to lexical skipping mode. */
 855   advance ();
 856 }
 857
 858 /* GC root declaration:
 859    (extern|static) gtymarker? type ID array_declarators_opt (';'|'=')
 860    If the gtymarker is not present, we ignore the rest of the declaration.  */
 861 static void
 862 extern_or_static (void)
 863 {
 864   options_p opts, opts2, dopts;
 865   type_p ty, dty;
 866   const char *name;
 867   require2 (EXTERN, STATIC);
 868
 869   if (token () != GTY_TOKEN)
 870     {
 871       advance ();
 872       return;
 873     }
 874
 875   opts = gtymarker ();
 876   ty = type (&opts2, true);     /* if we get here, it's got a GTY(()) */
 877   dty = declarator (ty, &name, &dopts);
 878
 879   if ((opts && dopts) || (opts && opts2) || (opts2 && dopts))
 880     parse_error ("GTY((...)) specified more than once for %s", name);
 881   else if (opts2)
 882     opts = opts2;
 883   else if (dopts)
 884     opts = dopts;
 885
 886   if (dty)
 887     {
 888       note_variable (name, adjust_field_type (dty, opts), opts, &lexer_line);
 889       require2 (';', '=');
 890     }
 891 }
 892
 893 /* Definition of a generic VEC structure:
 894
 895    'DEF_VEC_[IPO]' '(' id ')' ';'
 896
 897    Scalar VECs require slightly different treatment than otherwise -
 898    that's handled in note_def_vec, we just pass it along.*/
 899 static void
 900 def_vec (void)
 901 {
 902   bool is_scalar = (token () == DEFVEC_I);
 903   const char *type;
 904
 905   require2 (DEFVEC_OP, DEFVEC_I);
 906   require ('(');
 907   type = require2 (ID, SCALAR);
 908   require (')');
 909   require (';');
 910
 911   if (!type)
 912     return;
 913
 914   note_def_vec (type, is_scalar, &lexer_line);
 915   note_def_vec_alloc (type, "none", &lexer_line);
 916 }
 917
 918 /* Definition of an allocation strategy for a VEC structure:
 919
 920    'DEF_VEC_ALLOC_[IPO]' '(' id ',' id ')' ';'
 921
 922    For purposes of gengtype, this just declares a wrapper structure.  */
 923 static void
 924 def_vec_alloc (void)
 925 {
 926   const char *type, *astrat;
 927
 928   require (DEFVEC_ALLOC);
 929   require ('(');
 930   type = require2 (ID, SCALAR);
 931   require (',');
 932   astrat = require (ID);
 933   require (')');
 934   require (';');
 935
 936   if (!type || !astrat)
 937     return;
 938
 939   note_def_vec_alloc (type, astrat, &lexer_line);
 940 }
 941
 942 /* Parse the file FNAME for GC-relevant declarations and definitions.
 943    This is the only entry point to this file.  */
 944 void
 945 parse_file (const char *fname)
 946 {
 947   yybegin (fname);
 948   for (;;)
 949     {
 950       switch (token ())
 951         {
 952         case EXTERN:
 953         case STATIC:
 954           extern_or_static ();
 955           break;
 956
 957         case STRUCT:
 958         case UNION:
 959           struct_or_union ();
 960           break;
 961
 962         case TYPEDEF:
 963           typedef_decl ();
 964           break;
 965
 966         case DEFVEC_OP:
 967         case DEFVEC_I:
 968           def_vec ();
 969           break;
 970
 971         case DEFVEC_ALLOC:
 972           def_vec_alloc ();
 973           break;
 974
 975         case EOF_TOKEN:
 976           goto eof;
 977
 978         default:
 979           parse_error ("unexpected top level token, %s", print_cur_token ());
 980           goto eof;
 981         }
 982       lexer_toplevel_done = 1;
 983     }
 984
 985  eof:
 986   advance ();
 987   yyend ();
 988 }