expression.c

   1 /*
   2  * sparse/expression.c
   3  *
   4  * Copyright (C) 2003 Transmeta Corp.
   5  *               2003-2004 Linus Torvalds
   6  *
   7  * Permission is hereby granted, free of charge, to any person obtaining a copy
   8  * of this software and associated documentation files (the "Software"), to deal
   9  * in the Software without restriction, including without limitation the rights
  10  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  11  * copies of the Software, and to permit persons to whom the Software is
  12  * furnished to do so, subject to the following conditions:
  13  *
  14  * The above copyright notice and this permission notice shall be included in
  15  * all copies or substantial portions of the Software.
  16  *
  17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  18  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  20  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  21  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  22  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  23  * THE SOFTWARE.
  24  *
  25  * This is the expression parsing part of parsing C.
  26  */
  27 #include <stdarg.h>
  28 #include <stdlib.h>
  29 #include <stdio.h>
  30 #include <string.h>
  31 #include <ctype.h>
  32 #include <unistd.h>
  33 #include <fcntl.h>
  34 #include <errno.h>
  35 #include <limits.h>
  36
  37 #include "lib.h"
  38 #include "allocate.h"
  39 #include "token.h"
  40 #include "parse.h"
  41 #include "symbol.h"
  42 #include "scope.h"
  43 #include "expression.h"
  44 #include "target.h"
  45 #include "char.h"
  46
  47 static int match_oplist(int op, ...)
  48 {
  49         va_list args;
  50         int nextop;
  51
  52         va_start(args, op);
  53         do {
  54                 nextop = va_arg(args, int);
  55         } while (nextop != 0 && nextop != op);
  56         va_end(args);
  57
  58         return nextop != 0;
  59 }
  60
  61 static struct token *comma_expression(struct token *, struct expression **);
  62
  63 struct token *parens_expression(struct token *token, struct expression **expr, const char *where)
  64 {
  65         token = expect(token, '(', where);
  66         if (match_op(token, '{')) {
  67                 struct expression *e = alloc_expression(token->pos, EXPR_STATEMENT);
  68                 struct statement *stmt = alloc_statement(token->pos, STMT_COMPOUND);
  69                 *expr = e;
  70                 e->statement = stmt;
  71                 start_symbol_scope(e->pos);
  72                 token = compound_statement(token->next, stmt);
  73                 end_symbol_scope();
  74                 token = expect(token, '}', "at end of statement expression");
  75         } else
  76                 token = parse_expression(token, expr);
  77         return expect(token, ')', where);
  78 }
  79
  80 /*
  81  * Handle __func__, __FUNCTION__ and __PRETTY_FUNCTION__ token
  82  * conversion
  83  */
  84 static struct symbol *handle_func(struct token *token)
  85 {
  86         struct ident *ident = token->ident;
  87         struct symbol *decl, *array;
  88         struct string *string;
  89         int len;
  90
  91         if (ident != &__func___ident &&
  92             ident != &__FUNCTION___ident &&
  93             ident != &__PRETTY_FUNCTION___ident)
  94                 return NULL;
  95
  96         if (!current_fn || !current_fn->ident)
  97                 return NULL;
  98
  99         /* OK, it's one of ours */
 100         array = alloc_symbol(token->pos, SYM_ARRAY);
 101         array->ctype.base_type = &char_ctype;
 102         array->ctype.alignment = 1;
 103         array->endpos = token->pos;
 104         decl = alloc_symbol(token->pos, SYM_NODE);
 105         decl->ctype.base_type = array;
 106         decl->ctype.alignment = 1;
 107         decl->ctype.modifiers = MOD_STATIC;
 108         decl->endpos = token->pos;
 109
 110         /* function-scope, but in NS_SYMBOL */
 111         bind_symbol(decl, ident, NS_LABEL);
 112         decl->namespace = NS_SYMBOL;
 113
 114         len = current_fn->ident->len;
 115         string = __alloc_string(len + 1);
 116         memcpy(string->data, current_fn->ident->name, len);
 117         string->data[len] = 0;
 118         string->length = len + 1;
 119
 120         decl->initializer = alloc_expression(token->pos, EXPR_STRING);
 121         decl->initializer->string = string;
 122         decl->initializer->ctype = decl;
 123         decl->array_size = alloc_const_expression(token->pos, len + 1);
 124         array->array_size = decl->array_size;
 125         decl->bit_size = array->bit_size = bytes_to_bits(len + 1);
 126
 127         return decl;
 128 }
 129
 130 static struct token *parse_type(struct token *token, struct expression **tree)
 131 {
 132         struct symbol *sym;
 133         *tree = alloc_expression(token->pos, EXPR_TYPE);
 134         (*tree)->flags = Int_const_expr; /* sic */
 135         token = typename(token, &sym, NULL);
 136         if (sym->ident)
 137                 sparse_error(token->pos,
 138                              "type expression should not include identifier "
 139                              "\"%s\"", sym->ident->name);
 140         (*tree)->symbol = sym;
 141         return token;
 142 }
 143
 144 static struct token *builtin_types_compatible_p_expr(struct token *token,
 145                                                      struct expression **tree)
 146 {
 147         struct expression *expr = alloc_expression(
 148                 token->pos, EXPR_COMPARE);
 149         expr->flags = Int_const_expr;
 150         expr->op = SPECIAL_EQUAL;
 151         token = token->next;
 152         if (!match_op(token, '('))
 153                 return expect(token, '(',
 154                               "after __builtin_types_compatible_p");
 155         token = token->next;
 156         token = parse_type(token, &expr->left);
 157         if (!match_op(token, ','))
 158                 return expect(token, ',',
 159                               "in __builtin_types_compatible_p");
 160         token = token->next;
 161         token = parse_type(token, &expr->right);
 162         if (!match_op(token, ')'))
 163                 return expect(token, ')',
 164                               "at end of __builtin_types_compatible_p");
 165         token = token->next;
 166
 167         *tree = expr;
 168         return token;
 169 }
 170
 171 static struct token *builtin_offsetof_expr(struct token *token,
 172                                            struct expression **tree)
 173 {
 174         struct expression *expr = NULL;
 175         struct expression **p = &expr;
 176         struct symbol *sym;
 177         int op = '.';
 178
 179         token = token->next;
 180         if (!match_op(token, '('))
 181                 return expect(token, '(', "after __builtin_offset");
 182
 183         token = token->next;
 184         token = typename(token, &sym, NULL);
 185         if (sym->ident)
 186                 sparse_error(token->pos,
 187                              "type expression should not include identifier "
 188                              "\"%s\"", sym->ident->name);
 189
 190         if (!match_op(token, ','))
 191                 return expect(token, ',', "in __builtin_offset");
 192
 193         while (1) {
 194                 struct expression *e;
 195                 switch (op) {
 196                 case ')':
 197                         expr->in = sym;
 198                         *tree = expr;
 199                 default:
 200                         return expect(token, ')', "at end of __builtin_offset");
 201                 case SPECIAL_DEREFERENCE:
 202                         e = alloc_expression(token->pos, EXPR_OFFSETOF);
 203                         e->flags = Int_const_expr;
 204                         e->op = '[';
 205                         *p = e;
 206                         p = &e->down;
 207                         /* fall through */
 208                 case '.':
 209                         token = token->next;
 210                         e = alloc_expression(token->pos, EXPR_OFFSETOF);
 211                         e->flags = Int_const_expr;
 212                         e->op = '.';
 213                         if (token_type(token) != TOKEN_IDENT) {
 214                                 sparse_error(token->pos, "Expected member name");
 215                                 return token;
 216                         }
 217                         e->ident = token->ident;
 218                         token = token->next;
 219                         break;
 220                 case '[':
 221                         token = token->next;
 222                         e = alloc_expression(token->pos, EXPR_OFFSETOF);
 223                         e->flags = Int_const_expr;
 224                         e->op = '[';
 225                         token = parse_expression(token, &e->index);
 226                         token = expect(token, ']',
 227                                         "at end of array dereference");
 228                         if (!e->index)
 229                                 return token;
 230                 }
 231                 *p = e;
 232                 p = &e->down;
 233                 op = token_type(token) == TOKEN_SPECIAL ? token->special : 0;
 234         }
 235 }
 236
 237 #ifndef ULLONG_MAX
 238 #define ULLONG_MAX (~0ULL)
 239 #endif
 240
 241 static unsigned long long parse_num(const char *nptr, char **end)
 242 {
 243         if (nptr[0] == '0' && tolower(nptr[1]) == 'b')
 244                 return strtoull(&nptr[2], end, 2);
 245         return strtoull(nptr, end, 0);
 246 }
 247
 248 static void get_number_value(struct expression *expr, struct token *token)
 249 {
 250         const char *str = token->number;
 251         unsigned long long value;
 252         char *end;
 253         int size = 0, want_unsigned = 0;
 254         int overflow = 0, do_warn = 0;
 255         int try_unsigned = 1;
 256         int bits;
 257
 258         errno = 0;
 259         value = parse_num(str, &end);
 260         if (end == str)
 261                 goto Float;
 262         if (value == ULLONG_MAX && errno == ERANGE)
 263                 overflow = 1;
 264         while (1) {
 265                 char c = *end++;
 266                 if (!c) {
 267                         break;
 268                 } else if (c == 'u' || c == 'U') {
 269                         if (want_unsigned)
 270                                 goto Enoint;
 271                         want_unsigned = 1;
 272                 } else if (c == 'l' || c == 'L') {
 273                         if (size)
 274                                 goto Enoint;
 275                         size = 1;
 276                         if (*end == c) {
 277                                 size = 2;
 278                                 end++;
 279                         }
 280                 } else
 281                         goto Float;
 282         }
 283         if (overflow)
 284                 goto Eoverflow;
 285         /* OK, it's a valid integer */
 286         /* decimals can be unsigned only if directly specified as such */
 287         if (str[0] != '0' && !want_unsigned)
 288                 try_unsigned = 0;
 289         if (!size) {
 290                 bits = bits_in_int - 1;
 291                 if (!(value & (~1ULL << bits))) {
 292                         if (!(value & (1ULL << bits))) {
 293                                 goto got_it;
 294                         } else if (try_unsigned) {
 295                                 want_unsigned = 1;
 296                                 goto got_it;
 297                         }
 298                 }
 299                 size = 1;
 300                 do_warn = 1;
 301         }
 302         if (size < 2) {
 303                 bits = bits_in_long - 1;
 304                 if (!(value & (~1ULL << bits))) {
 305                         if (!(value & (1ULL << bits))) {
 306                                 goto got_it;
 307                         } else if (try_unsigned) {
 308                                 want_unsigned = 1;
 309                                 goto got_it;
 310                         }
 311                         do_warn |= 2;
 312                 }
 313                 size = 2;
 314                 do_warn |= 1;
 315         }
 316         bits = bits_in_longlong - 1;
 317         if (value & (~1ULL << bits))
 318                 goto Eoverflow;
 319         if (!(value & (1ULL << bits)))
 320                 goto got_it;
 321         if (!try_unsigned)
 322                 warning(expr->pos, "decimal constant %s is too big for long long",
 323                         show_token(token));
 324         want_unsigned = 1;
 325 got_it:
 326         if (do_warn)
 327                 warning(expr->pos, "constant %s is so big it is%s%s%s",
 328                         show_token(token),
 329                         want_unsigned ? " unsigned":"",
 330                         size > 0 ? " long":"",
 331                         size > 1 ? " long":"");
 332         if (do_warn & 2)
 333                 warning(expr->pos,
 334                         "decimal constant %s is between LONG_MAX and ULONG_MAX."
 335                         " For C99 that means long long, C90 compilers are very "
 336                         "likely to produce unsigned long (and a warning) here",
 337                         show_token(token));
 338         expr->type = EXPR_VALUE;
 339         expr->flags = Int_const_expr;
 340         expr->ctype = ctype_integer(size, want_unsigned);
 341         expr->value = value;
 342         return;
 343 Eoverflow:
 344         error_die(expr->pos, "constant %s is too big even for unsigned long long",
 345                         show_token(token));
 346         return;
 347 Float:
 348         expr->fvalue = string_to_ld(str, &end);
 349         if (str == end)
 350                 goto Enoint;
 351
 352         if (*end && end[1])
 353                 goto Enoint;
 354
 355         if (*end == 'f' || *end == 'F')
 356                 expr->ctype = &float_ctype;
 357         else if (*end == 'l' || *end == 'L')
 358                 expr->ctype = &ldouble_ctype;
 359         else if (!*end)
 360                 expr->ctype = &double_ctype;
 361         else
 362                 goto Enoint;
 363
 364         expr->flags = Float_literal;
 365         expr->type = EXPR_FVALUE;
 366         return;
 367
 368 Enoint:
 369         error_die(expr->pos, "constant %s is not a valid number", show_token(token));
 370 }
 371
 372 struct token *primary_expression(struct token *token, struct expression **tree)
 373 {
 374         struct expression *expr = NULL;
 375
 376         switch (token_type(token)) {
 377         case TOKEN_CHAR ... TOKEN_WIDE_CHAR_EMBEDDED_3:
 378                 expr = alloc_expression(token->pos, EXPR_VALUE);
 379                 expr->flags = Int_const_expr;
 380                 expr->ctype = token_type(token) < TOKEN_WIDE_CHAR ? &int_ctype : &long_ctype;
 381                 get_char_constant(token, &expr->value);
 382                 token = token->next;
 383                 break;
 384
 385         case TOKEN_NUMBER:
 386                 expr = alloc_expression(token->pos, EXPR_VALUE);
 387                 get_number_value(expr, token); /* will see if it's an integer */
 388                 token = token->next;
 389                 break;
 390
 391         case TOKEN_ZERO_IDENT: {
 392                 expr = alloc_expression(token->pos, EXPR_SYMBOL);
 393                 expr->flags = Int_const_expr;
 394                 expr->ctype = &int_ctype;
 395                 expr->symbol = &zero_int;
 396                 expr->symbol_name = token->ident;
 397                 token = token->next;
 398                 break;
 399         }
 400
 401         case TOKEN_IDENT: {
 402                 struct symbol *sym = lookup_symbol(token->ident, NS_SYMBOL | NS_TYPEDEF);
 403                 struct token *next = token->next;
 404
 405                 if (!sym) {
 406                         sym = handle_func(token);
 407                         if (token->ident == &__builtin_types_compatible_p_ident) {
 408                                 token = builtin_types_compatible_p_expr(token, &expr);
 409                                 break;
 410                         }
 411                         if (token->ident == &__builtin_offsetof_ident) {
 412                                 token = builtin_offsetof_expr(token, &expr);
 413                                 break;
 414                         }
 415                 } else if (sym->enum_member) {
 416                         expr = alloc_expression(token->pos, EXPR_VALUE);
 417                         *expr = *sym->initializer;
 418                         /* we want the right position reported, thus the copy */
 419                         expr->pos = token->pos;
 420                         expr->flags = Int_const_expr;
 421                         token = next;
 422                         break;
 423                 }
 424
 425                 expr = alloc_expression(token->pos, EXPR_SYMBOL);
 426
 427                 /*
 428                  * We support types as real first-class citizens, with type
 429                  * comparisons etc:
 430                  *
 431                  *      if (typeof(a) == int) ..
 432                  */
 433                 if (sym && sym->namespace == NS_TYPEDEF) {
 434                         sparse_error(token->pos, "typename in expression");
 435                         sym = NULL;
 436                 }
 437                 expr->symbol_name = token->ident;
 438                 expr->symbol = sym;
 439                 token = next;
 440                 break;
 441         }
 442
 443         case TOKEN_STRING:
 444         case TOKEN_WIDE_STRING:
 445                 expr = alloc_expression(token->pos, EXPR_STRING);
 446                 token = get_string_constant(token, expr);
 447                 break;
 448
 449         case TOKEN_SPECIAL:
 450                 if (token->special == '(') {
 451                         expr = alloc_expression(token->pos, EXPR_PREOP);
 452                         expr->op = '(';
 453                         token = parens_expression(token, &expr->unop, "in expression");
 454                         if (expr->unop)
 455                                 expr->flags = expr->unop->flags;
 456                         break;
 457                 }
 458                 if (token->special == '[' && lookup_type(token->next)) {
 459                         expr = alloc_expression(token->pos, EXPR_TYPE);
 460                         expr->flags = Int_const_expr; /* sic */
 461                         token = typename(token->next, &expr->symbol, NULL);
 462                         token = expect(token, ']', "in type expression");
 463                         break;
 464                 }
 465
 466         default:
 467                 ;
 468         }
 469         *tree = expr;
 470         return token;
 471 }
 472
 473 static struct token *expression_list(struct token *token, struct expression_list **list)
 474 {
 475         while (!match_op(token, ')')) {
 476                 struct expression *expr = NULL;
 477                 token = assignment_expression(token, &expr);
 478                 if (!expr)
 479                         break;
 480                 add_expression(list, expr);
 481                 if (!match_op(token, ','))
 482                         break;
 483                 token = token->next;
 484         }
 485         return token;
 486 }
 487
 488 /*
 489  * extend to deal with the ambiguous C grammar for parsing
 490  * a cast expressions followed by an initializer.
 491  */
 492 static struct token *postfix_expression(struct token *token, struct expression **tree, struct expression *cast_init_expr)
 493 {
 494         struct expression *expr = cast_init_expr;
 495
 496         if (!expr)
 497                 token = primary_expression(token, &expr);
 498
 499         while (expr && token_type(token) == TOKEN_SPECIAL) {
 500                 switch (token->special) {
 501                 case '[': {                     /* Array dereference */
 502                         struct expression *deref = alloc_expression(token->pos, EXPR_PREOP);
 503                         struct expression *add = alloc_expression(token->pos, EXPR_BINOP);
 504
 505                         deref->op = '*';
 506                         deref->unop = add;
 507
 508                         add->op = '+';
 509                         add->left = expr;
 510                         token = parse_expression(token->next, &add->right);
 511                         token = expect(token, ']', "at end of array dereference");
 512                         expr = deref;
 513                         continue;
 514                 }
 515                 case SPECIAL_INCREMENT:         /* Post-increment */
 516                 case SPECIAL_DECREMENT: {       /* Post-decrement */
 517                         struct expression *post = alloc_expression(token->pos, EXPR_POSTOP);
 518                         post->op = token->special;
 519                         post->unop = expr;
 520                         expr = post;
 521                         token = token->next;
 522                         continue;
 523                 }
 524                 case SPECIAL_DEREFERENCE: {     /* Structure pointer member dereference */
 525                         /* "x->y" is just shorthand for "(*x).y" */
 526                         struct expression *inner = alloc_expression(token->pos, EXPR_PREOP);
 527                         inner->op = '*';
 528                         inner->unop = expr;
 529                         expr = inner;
 530                 }
 531                 /* Fall through!! */
 532                 case '.': {                     /* Structure member dereference */
 533                         struct expression *deref = alloc_expression(token->pos, EXPR_DEREF);
 534                         deref->op = '.';
 535                         deref->deref = expr;
 536                         token = token->next;
 537                         if (token_type(token) != TOKEN_IDENT) {
 538                                 sparse_error(token->pos, "Expected member name");
 539                                 break;
 540                         }
 541                         deref->member = token->ident;
 542                         token = token->next;
 543                         expr = deref;
 544                         continue;
 545                 }
 546
 547                 case '(': {                     /* Function call */
 548                         struct expression *call = alloc_expression(token->pos, EXPR_CALL);
 549                         call->op = '(';
 550                         call->fn = expr;
 551                         token = expression_list(token->next, &call->args);
 552                         token = expect(token, ')', "in function call");
 553                         expr = call;
 554                         continue;
 555                 }
 556
 557                 default:
 558                         break;
 559                 }
 560                 break;
 561         }
 562         *tree = expr;
 563         return token;
 564 }
 565
 566 static struct token *cast_expression(struct token *token, struct expression **tree);
 567 static struct token *unary_expression(struct token *token, struct expression **tree);
 568
 569 static struct token *type_info_expression(struct token *token,
 570         struct expression **tree, int type)
 571 {
 572         struct expression *expr = alloc_expression(token->pos, type);
 573         struct token *p;
 574
 575         *tree = expr;
 576         expr->flags = Int_const_expr; /* XXX: VLA support will need that changed */
 577         token = token->next;
 578         if (!match_op(token, '(') || !lookup_type(token->next))
 579                 return unary_expression(token, &expr->cast_expression);
 580         p = token;
 581         token = typename(token->next, &expr->cast_type, NULL);
 582
 583         if (!match_op(token, ')')) {
 584                 static const char * error[] = {
 585                         [EXPR_SIZEOF] = "at end of sizeof",
 586                         [EXPR_ALIGNOF] = "at end of __alignof__",
 587                         [EXPR_PTRSIZEOF] = "at end of __sizeof_ptr__"
 588                 };
 589                 return expect(token, ')', error[type]);
 590         }
 591
 592         token = token->next;
 593         /*
 594          * C99 ambiguity: the typename might have been the beginning
 595          * of a typed initializer expression..
 596          */
 597         if (match_op(token, '{')) {
 598                 struct expression *cast = alloc_expression(p->pos, EXPR_CAST);
 599                 cast->cast_type = expr->cast_type;
 600                 expr->cast_type = NULL;
 601                 expr->cast_expression = cast;
 602                 token = initializer(&cast->cast_expression, token);
 603                 token = postfix_expression(token, &expr->cast_expression, cast);
 604         }
 605         return token;
 606 }
 607
 608 static struct token *unary_expression(struct token *token, struct expression **tree)
 609 {
 610         if (token_type(token) == TOKEN_IDENT) {
 611                 struct ident *ident = token->ident;
 612                 if (ident->reserved) {
 613                         static const struct {
 614                                 struct ident *id;
 615                                 int type;
 616                         } type_information[] = {
 617                                 { &sizeof_ident, EXPR_SIZEOF },
 618                                 { &__alignof___ident, EXPR_ALIGNOF },
 619                                 { &__alignof_ident, EXPR_ALIGNOF },
 620                                 { &__sizeof_ptr___ident, EXPR_PTRSIZEOF },
 621                         };
 622                         int i;
 623                         for (i = 0; i < ARRAY_SIZE(type_information); i++) {
 624                                 if (ident == type_information[i].id)
 625                                         return type_info_expression(token, tree, type_information[i].type);
 626                         }
 627                 }
 628         }
 629
 630         if (token_type(token) == TOKEN_SPECIAL) {
 631                 if (match_oplist(token->special,
 632                     SPECIAL_INCREMENT, SPECIAL_DECREMENT,
 633                     '&', '*', 0)) {
 634                         struct expression *unop;
 635                         struct expression *unary;
 636                         struct token *next;
 637
 638                         next = cast_expression(token->next, &unop);
 639                         if (!unop) {
 640                                 sparse_error(token->pos, "Syntax error in unary expression");
 641                                 *tree = NULL;
 642                                 return next;
 643                         }
 644                         unary = alloc_expression(token->pos, EXPR_PREOP);
 645                         unary->op = token->special;
 646                         unary->unop = unop;
 647                         *tree = unary;
 648                         return next;
 649                 }
 650                 /* possibly constant ones */
 651                 if (match_oplist(token->special, '+', '-', '~', '!', 0)) {
 652                         struct expression *unop;
 653                         struct expression *unary;
 654                         struct token *next;
 655
 656                         next = cast_expression(token->next, &unop);
 657                         if (!unop) {
 658                                 sparse_error(token->pos, "Syntax error in unary expression");
 659                                 *tree = NULL;
 660                                 return next;
 661                         }
 662                         unary = alloc_expression(token->pos, EXPR_PREOP);
 663                         unary->op = token->special;
 664                         unary->unop = unop;
 665                         unary->flags = unop->flags & Int_const_expr;
 666                         *tree = unary;
 667                         return next;
 668                 }
 669                 /* Gcc extension: &&label gives the address of a label */
 670                 if (match_op(token, SPECIAL_LOGICAL_AND) &&
 671                     token_type(token->next) == TOKEN_IDENT) {
 672                         struct expression *label = alloc_expression(token->pos, EXPR_LABEL);
 673                         struct symbol *sym = label_symbol(token->next);
 674                         if (!(sym->ctype.modifiers & MOD_ADDRESSABLE)) {
 675                                 sym->ctype.modifiers |= MOD_ADDRESSABLE;
 676                                 add_symbol(&function_computed_target_list, sym);
 677                         }
 678                         label->label_symbol = sym;
 679                         *tree = label;
 680                         return token->next->next;
 681                 }
 682
 683         }
 684
 685         return postfix_expression(token, tree, NULL);
 686 }
 687
 688 /*
 689  * Ambiguity: a '(' can be either a cast-expression or
 690  * a primary-expression depending on whether it is followed
 691  * by a type or not.
 692  *
 693  * additional ambiguity: a "cast expression" followed by
 694  * an initializer is really a postfix-expression.
 695  */
 696 static struct token *cast_expression(struct token *token, struct expression **tree)
 697 {
 698         if (match_op(token, '(')) {
 699                 struct token *next = token->next;
 700                 if (lookup_type(next)) {
 701                         struct expression *cast = alloc_expression(next->pos, EXPR_CAST);
 702                         struct expression *v;
 703                         struct symbol *sym;
 704                         int is_force;
 705
 706                         token = typename(next, &sym, &is_force);
 707                         cast->cast_type = sym;
 708                         token = expect(token, ')', "at end of cast operator");
 709                         if (match_op(token, '{')) {
 710                                 if (is_force)
 711                                         warning(sym->pos,
 712                                                 "[force] in compound literal");
 713                                 token = initializer(&cast->cast_expression, token);
 714                                 return postfix_expression(token, tree, cast);
 715                         }
 716                         *tree = cast;
 717                         if (is_force)
 718                                 cast->type = EXPR_FORCE_CAST;
 719                         token = cast_expression(token, &v);
 720                         if (!v)
 721                                 return token;
 722                         cast->cast_expression = v;
 723                         if (v->flags & Int_const_expr)
 724                                 cast->flags = Int_const_expr;
 725                         else if (v->flags & Float_literal) /* and _not_ int */
 726                                 cast->flags = Int_const_expr | Float_literal;
 727                         return token;
 728                 }
 729         }
 730         return unary_expression(token, tree);
 731 }
 732
 733 /*
 734  * Generic left-to-right binop parsing
 735  *
 736  * This _really_ needs to be inlined, because that makes the inner
 737  * function call statically deterministic rather than a totally
 738  * unpredictable indirect call. But gcc-3 is so "clever" that it
 739  * doesn't do so by default even when you tell it to inline it.
 740  *
 741  * Making it a macro avoids the inlining problem, and also means
 742  * that we can pass in the op-comparison as an expression rather
 743  * than create a data structure for it.
 744  */
 745
 746 #define LR_BINOP_EXPRESSION(__token, tree, type, inner, compare)        \
 747         struct expression *left = NULL;                                 \
 748         struct token * next = inner(__token, &left);                    \
 749                                                                         \
 750         if (left) {                                                     \
 751                 while (token_type(next) == TOKEN_SPECIAL) {             \
 752                         struct expression *top, *right = NULL;          \
 753                         int op = next->special;                         \
 754                                                                         \
 755                         if (!(compare))                                 \
 756                                 goto out;                               \
 757                         top = alloc_expression(next->pos, type);        \
 758                         next = inner(next->next, &right);               \
 759                         if (!right) {                                   \
 760                                 sparse_error(next->pos, "No right hand side of '%s'-expression", show_special(op));     \
 761                                 break;                                  \
 762                         }                                               \
 763                         top->flags = left->flags & right->flags         \
 764                                                 & Int_const_expr;       \
 765                         top->op = op;                                   \
 766                         top->left = left;                               \
 767                         top->right = right;                             \
 768                         left = top;                                     \
 769                 }                                                       \
 770         }                                                               \
 771 out:                                                                    \
 772         *tree = left;                                                   \
 773         return next;                                                    \
 774
 775 static struct token *multiplicative_expression(struct token *token, struct expression **tree)
 776 {
 777         LR_BINOP_EXPRESSION(
 778                 token, tree, EXPR_BINOP, cast_expression,
 779                 (op == '*') || (op == '/') || (op == '%')
 780         );
 781 }
 782
 783 static struct token *additive_expression(struct token *token, struct expression **tree)
 784 {
 785         LR_BINOP_EXPRESSION(
 786                 token, tree, EXPR_BINOP, multiplicative_expression,
 787                 (op == '+') || (op == '-')
 788         );
 789 }
 790
 791 static struct token *shift_expression(struct token *token, struct expression **tree)
 792 {
 793         LR_BINOP_EXPRESSION(
 794                 token, tree, EXPR_BINOP, additive_expression,
 795                 (op == SPECIAL_LEFTSHIFT) || (op == SPECIAL_RIGHTSHIFT)
 796         );
 797 }
 798
 799 static struct token *relational_expression(struct token *token, struct expression **tree)
 800 {
 801         LR_BINOP_EXPRESSION(
 802                 token, tree, EXPR_COMPARE, shift_expression,
 803                 (op == '<') || (op == '>') ||
 804                 (op == SPECIAL_LTE) || (op == SPECIAL_GTE)
 805         );
 806 }
 807
 808 static struct token *equality_expression(struct token *token, struct expression **tree)
 809 {
 810         LR_BINOP_EXPRESSION(
 811                 token, tree, EXPR_COMPARE, relational_expression,
 812                 (op == SPECIAL_EQUAL) || (op == SPECIAL_NOTEQUAL)
 813         );
 814 }
 815
 816 static struct token *bitwise_and_expression(struct token *token, struct expression **tree)
 817 {
 818         LR_BINOP_EXPRESSION(
 819                 token, tree, EXPR_BINOP, equality_expression,
 820                 (op == '&')
 821         );
 822 }
 823
 824 static struct token *bitwise_xor_expression(struct token *token, struct expression **tree)
 825 {
 826         LR_BINOP_EXPRESSION(
 827                 token, tree, EXPR_BINOP, bitwise_and_expression,
 828                 (op == '^')
 829         );
 830 }
 831
 832 static struct token *bitwise_or_expression(struct token *token, struct expression **tree)
 833 {
 834         LR_BINOP_EXPRESSION(
 835                 token, tree, EXPR_BINOP, bitwise_xor_expression,
 836                 (op == '|')
 837         );
 838 }
 839
 840 static struct token *logical_and_expression(struct token *token, struct expression **tree)
 841 {
 842         LR_BINOP_EXPRESSION(
 843                 token, tree, EXPR_LOGICAL, bitwise_or_expression,
 844                 (op == SPECIAL_LOGICAL_AND)
 845         );
 846 }
 847
 848 static struct token *logical_or_expression(struct token *token, struct expression **tree)
 849 {
 850         LR_BINOP_EXPRESSION(
 851                 token, tree, EXPR_LOGICAL, logical_and_expression,
 852                 (op == SPECIAL_LOGICAL_OR)
 853         );
 854 }
 855
 856 struct token *conditional_expression(struct token *token, struct expression **tree)
 857 {
 858         token = logical_or_expression(token, tree);
 859         if (*tree && match_op(token, '?')) {
 860                 struct expression *expr = alloc_expression(token->pos, EXPR_CONDITIONAL);
 861                 expr->op = token->special;
 862                 expr->left = *tree;
 863                 *tree = expr;
 864                 token = parse_expression(token->next, &expr->cond_true);
 865                 token = expect(token, ':', "in conditional expression");
 866                 token = conditional_expression(token, &expr->cond_false);
 867                 if (expr->left && expr->cond_false) {
 868                         int is_const = expr->left->flags &
 869                                         expr->cond_false->flags &
 870                                         Int_const_expr;
 871                         if (expr->cond_true)
 872                                 is_const &= expr->cond_true->flags;
 873                         expr->flags = is_const;
 874                 }
 875         }
 876         return token;
 877 }
 878
 879 struct token *assignment_expression(struct token *token, struct expression **tree)
 880 {
 881         token = conditional_expression(token, tree);
 882         if (*tree && token_type(token) == TOKEN_SPECIAL) {
 883                 static const int assignments[] = {
 884                         '=',
 885                         SPECIAL_ADD_ASSIGN, SPECIAL_SUB_ASSIGN,
 886                         SPECIAL_MUL_ASSIGN, SPECIAL_DIV_ASSIGN,
 887                         SPECIAL_MOD_ASSIGN, SPECIAL_SHL_ASSIGN,
 888                         SPECIAL_SHR_ASSIGN, SPECIAL_AND_ASSIGN,
 889                         SPECIAL_OR_ASSIGN,  SPECIAL_XOR_ASSIGN };
 890                 int i, op = token->special;
 891                 for (i = 0; i < ARRAY_SIZE(assignments); i++)
 892                         if (assignments[i] == op) {
 893                                 struct expression * expr = alloc_expression(token->pos, EXPR_ASSIGNMENT);
 894                                 expr->left = *tree;
 895                                 expr->op = op;
 896                                 *tree = expr;
 897                                 return assignment_expression(token->next, &expr->right);
 898                         }
 899         }
 900         return token;
 901 }
 902
 903 static struct token *comma_expression(struct token *token, struct expression **tree)
 904 {
 905         LR_BINOP_EXPRESSION(
 906                 token, tree, EXPR_COMMA, assignment_expression,
 907                 (op == ',')
 908         );
 909 }
 910
 911 struct token *parse_expression(struct token *token, struct expression **tree)
 912 {
 913         return comma_expression(token,tree);
 914 }
 915
 916