expression.c

   1 /*
   2  * sparse/expression.c
   3  *
   4  * Copyright (C) 2003 Transmeta Corp.
   5  *               2003-2004 Linus Torvalds
   6  *
   7  *  Licensed under the Open Software License version 1.1
   8  *
   9  * This is the expression parsing part of parsing C.
  10  */
  11 #include <stdarg.h>
  12 #include <stdlib.h>
  13 #include <stdio.h>
  14 #include <string.h>
  15 #include <ctype.h>
  16 #include <unistd.h>
  17 #include <fcntl.h>
  18 #include <errno.h>
  19 #include <limits.h>
  20
  21 #include "lib.h"
  22 #include "allocate.h"
  23 #include "token.h"
  24 #include "parse.h"
  25 #include "symbol.h"
  26 #include "scope.h"
  27 #include "expression.h"
  28 #include "target.h"
  29
  30 static int match_oplist(int op, ...)
  31 {
  32         va_list args;
  33
  34         va_start(args, op);
  35         for (;;) {
  36                 int nextop = va_arg(args, int);
  37                 if (!nextop)
  38                         return 0;
  39                 if (op == nextop)
  40                         return 1;
  41         }
  42 }
  43
  44 static struct token *comma_expression(struct token *, struct expression **);
  45
  46 struct token *parens_expression(struct token *token, struct expression **expr, const char *where)
  47 {
  48         token = expect(token, '(', where);
  49         if (match_op(token, '{')) {
  50                 struct expression *e = alloc_expression(token->pos, EXPR_STATEMENT);
  51                 struct statement *stmt = alloc_statement(token->pos, STMT_COMPOUND);
  52                 *expr = e;
  53                 e->statement = stmt;
  54                 start_symbol_scope();
  55                 token = compound_statement(token->next, stmt);
  56                 end_symbol_scope();
  57                 token = expect(token, '}', "at end of statement expression");
  58         } else
  59                 token = parse_expression(token, expr);
  60         return expect(token, ')', where);
  61 }
  62
  63 /*
  64  * Handle __func__, __FUNCTION__ and __PRETTY_FUNCTION__ token
  65  * conversion
  66  */
  67 static int convert_one_fn_token(struct token *token)
  68 {
  69         struct symbol *sym = current_fn;
  70
  71         if (sym) {
  72                 struct ident *ident = sym->ident;
  73                 if (ident) {
  74                         int len = ident->len;
  75                         struct string *string;
  76
  77                         string = __alloc_string(len+1);
  78                         memcpy(string->data, ident->name, len);
  79                         string->data[len] = 0;
  80                         string->length = len+1;
  81                         token_type(token) = TOKEN_STRING;
  82                         token->string = string;
  83                         return 1;
  84                 }
  85         }
  86         return 0;
  87 }
  88
  89 static int convert_function(struct token *next)
  90 {
  91         int retval = 0;
  92         for (;;) {
  93                 struct token *token = next;
  94                 next = next->next;
  95                 switch (token_type(token)) {
  96                 case TOKEN_STRING:
  97                         continue;
  98                 case TOKEN_IDENT:
  99                         if (token->ident == &__func___ident ||
 100                             token->ident == &__FUNCTION___ident ||
 101                             token->ident == &__PRETTY_FUNCTION___ident) {
 102                                 if (!convert_one_fn_token(token))
 103                                         break;
 104                                 retval = 1;
 105                                 continue;
 106                         }
 107                 /* Fall through */
 108                 default:
 109                         break;
 110                 }
 111                 break;
 112         }
 113         return retval;
 114 }
 115
 116 static struct token *parse_type(struct token *token, struct expression **tree)
 117 {
 118         struct symbol *sym;
 119         *tree = alloc_expression(token->pos, EXPR_TYPE);
 120         token = typename(token, &sym);
 121         if (sym->ident)
 122                 sparse_error(token->pos,
 123                              "type expression should not include identifier "
 124                              "\"%s\"", sym->ident->name);
 125         (*tree)->symbol = sym;
 126         return token;
 127 }
 128
 129 static struct token *builtin_types_compatible_p_expr(struct token *token,
 130                                                      struct expression **tree)
 131 {
 132         struct expression *expr = alloc_expression(
 133                 token->pos, EXPR_COMPARE);
 134         expr->op = SPECIAL_EQUAL;
 135         token = token->next;
 136         if (!match_op(token, '('))
 137                 return expect(token, '(',
 138                               "after __builtin_types_compatible_p");
 139         token = token->next;
 140         token = parse_type(token, &expr->left);
 141         if (!match_op(token, ','))
 142                 return expect(token, ',',
 143                               "in __builtin_types_compatible_p");
 144         token = token->next;
 145         token = parse_type(token, &expr->right);
 146         if (!match_op(token, ')'))
 147                 return expect(token, ')',
 148                               "at end of __builtin_types_compatible_p");
 149         token = token->next;
 150
 151         *tree = expr;
 152         return token;
 153 }
 154
 155 static struct token *string_expression(struct token *token, struct expression *expr)
 156 {
 157         struct string *string = token->string;
 158         struct token *next = token->next;
 159
 160         convert_function(token);
 161
 162         if (token_type(next) == TOKEN_STRING) {
 163                 int totlen = string->length-1;
 164                 char *data;
 165
 166                 do {
 167                         totlen += next->string->length-1;
 168                         next = next->next;
 169                 } while (token_type(next) == TOKEN_STRING);
 170
 171                 if (totlen > MAX_STRING) {
 172                         warning(token->pos, "trying to concatenate %d-character string (%d bytes max)", totlen, MAX_STRING);
 173                         totlen = MAX_STRING;
 174                 }
 175
 176                 string = __alloc_string(totlen+1);
 177                 string->length = totlen+1;
 178                 data = string->data;
 179                 next = token;
 180                 do {
 181                         struct string *s = next->string;
 182                         int len = s->length-1;
 183
 184                         if (len > totlen)
 185                                 len = totlen;
 186                         totlen -= len;
 187
 188                         next = next->next;
 189                         memcpy(data, s->data, len);
 190                         data += len;
 191                 } while (token_type(next) == TOKEN_STRING);
 192                 *data = '\0';
 193         }
 194         expr->string = string;
 195         return next;
 196 }
 197
 198 #ifndef ULLONG_MAX
 199 #define ULLONG_MAX (~0ULL)
 200 #endif
 201
 202 static void get_number_value(struct expression *expr, struct token *token)
 203 {
 204         const char *str = token->number;
 205         unsigned long long value;
 206         char *end;
 207         unsigned long modifiers = 0;
 208         int overflow = 0, do_warn = 0;
 209         int try_unsigned = 1;
 210         int bits;
 211
 212         errno = 0;
 213         value = strtoull(str, &end, 0);
 214         if (end == str)
 215                 goto Float;
 216         if (value == ULLONG_MAX && errno == ERANGE)
 217                 overflow = 1;
 218         while (1) {
 219                 unsigned long added;
 220                 char c = *end++;
 221                 if (!c) {
 222                         break;
 223                 } else if (c == 'u' || c == 'U') {
 224                         added = MOD_UNSIGNED;
 225                 } else if (c == 'l' || c == 'L') {
 226                         added = MOD_LONG;
 227                         if (*end == c) {
 228                                 added |= MOD_LONGLONG;
 229                                 end++;
 230                         }
 231                 } else
 232                         goto Float;
 233                 if (modifiers & added)
 234                         goto Enoint;
 235                 modifiers |= added;
 236         }
 237         if (overflow)
 238                 goto Eoverflow;
 239         /* OK, it's a valid integer */
 240         /* decimals can be unsigned only if directly specified as such */
 241         if (str[0] != '0' && !(modifiers & MOD_UNSIGNED))
 242                 try_unsigned = 0;
 243         if (!(modifiers & MOD_LONG)) {
 244                 bits = bits_in_int - 1;
 245                 if (!(value & (~1ULL << bits))) {
 246                         if (!(value & (1ULL << bits))) {
 247                                 goto got_it;
 248                         } else if (try_unsigned) {
 249                                 modifiers |= MOD_UNSIGNED;
 250                                 goto got_it;
 251                         }
 252                 }
 253                 modifiers |= MOD_LONG;
 254                 do_warn = 1;
 255         }
 256         if (!(modifiers & MOD_LONGLONG)) {
 257                 bits = bits_in_long - 1;
 258                 if (!(value & (~1ULL << bits))) {
 259                         if (!(value & (1ULL << bits))) {
 260                                 goto got_it;
 261                         } else if (try_unsigned) {
 262                                 modifiers |= MOD_UNSIGNED;
 263                                 goto got_it;
 264                         }
 265                         do_warn |= 2;
 266                 }
 267                 modifiers |= MOD_LONGLONG;
 268                 do_warn |= 1;
 269         }
 270         bits = bits_in_longlong - 1;
 271         if (value & (~1ULL << bits))
 272                 goto Eoverflow;
 273         if (!(value & (1ULL << bits)))
 274                 goto got_it;
 275         if (!try_unsigned)
 276                 warning(expr->pos, "decimal constant %s is too big for long long",
 277                         show_token(token));
 278         modifiers |= MOD_UNSIGNED;
 279 got_it:
 280         if (do_warn)
 281                 warning(expr->pos, "constant %s is so big it is%s%s%s",
 282                         show_token(token),
 283                         (modifiers & MOD_UNSIGNED) ? " unsigned":"",
 284                         (modifiers & MOD_LONG) ? " long":"",
 285                         (modifiers & MOD_LONGLONG) ? " long":"");
 286         if (do_warn & 2)
 287                 warning(expr->pos,
 288                         "decimal constant %s is between LONG_MAX and ULONG_MAX."
 289                         " For C99 that means long long, C90 compilers are very "
 290                         "likely to produce unsigned long (and a warning) here",
 291                         show_token(token));
 292         expr->type = EXPR_VALUE;
 293         expr->ctype = ctype_integer(modifiers);
 294         expr->value = value;
 295         return;
 296 Eoverflow:
 297         error_die(expr->pos, "constant %s is too big even for unsigned long long",
 298                         show_token(token));
 299         return;
 300 Float:
 301         expr->fvalue = string_to_ld(str, &end);
 302         if (str == end)
 303                 goto Enoint;
 304
 305         if (*end && end[1])
 306                 goto Enoint;
 307
 308         if (*end == 'f' || *end == 'F')
 309                 expr->ctype = &float_ctype;
 310         else if (*end == 'l' || *end == 'L')
 311                 expr->ctype = &ldouble_ctype;
 312         else if (!*end)
 313                 expr->ctype = &double_ctype;
 314         else
 315                 goto Enoint;
 316
 317         expr->type = EXPR_FVALUE;
 318         return;
 319
 320 Enoint:
 321         error_die(expr->pos, "constant %s is not a valid number", show_token(token));
 322 }
 323
 324 struct token *primary_expression(struct token *token, struct expression **tree)
 325 {
 326         struct expression *expr = NULL;
 327
 328         switch (token_type(token)) {
 329         case TOKEN_CHAR:
 330                 expr = alloc_expression(token->pos, EXPR_VALUE);
 331                 expr->ctype = &int_ctype;
 332                 expr->value = (unsigned char) token->character;
 333                 token = token->next;
 334                 break;
 335
 336         case TOKEN_NUMBER:
 337                 expr = alloc_expression(token->pos, EXPR_VALUE);
 338                 get_number_value(expr, token);
 339                 token = token->next;
 340                 break;
 341
 342         case TOKEN_ZERO_IDENT: {
 343                 expr = alloc_expression(token->pos, EXPR_SYMBOL);
 344                 expr->ctype = &int_ctype;
 345                 expr->symbol = &zero_int;
 346                 expr->symbol_name = token->ident;
 347                 token = token->next;
 348                 break;
 349         }
 350
 351         case TOKEN_IDENT: {
 352                 struct symbol *sym = lookup_symbol(token->ident, NS_SYMBOL | NS_TYPEDEF);
 353                 struct token *next = token->next;
 354
 355                 if (!sym) {
 356                         if (convert_function(token))
 357                                 goto handle_string;
 358                         if (token->ident == &__builtin_types_compatible_p_ident) {
 359                                 token = builtin_types_compatible_p_expr(token, &expr);
 360                                 break;
 361                         }
 362                 }
 363
 364                 expr = alloc_expression(token->pos, EXPR_SYMBOL);
 365
 366                 /*
 367                  * We support types as real first-class citizens, with type
 368                  * comparisons etc:
 369                  *
 370                  *      if (typeof(a) == int) ..
 371                  */
 372                 if (sym && sym->namespace == NS_TYPEDEF) {
 373                         sparse_error(token->pos, "typename in expression");
 374                         sym = NULL;
 375                 }
 376                 expr->symbol_name = token->ident;
 377                 expr->symbol = sym;
 378                 token = next;
 379                 break;
 380         }
 381
 382         case TOKEN_STRING: {
 383         handle_string:
 384                 expr = alloc_expression(token->pos, EXPR_STRING);
 385                 token = string_expression(token, expr);
 386                 break;
 387         }
 388
 389         case TOKEN_SPECIAL:
 390                 if (token->special == '(') {
 391                         expr = alloc_expression(token->pos, EXPR_PREOP);
 392                         expr->op = '(';
 393                         token = parens_expression(token, &expr->unop, "in expression");
 394                         break;
 395                 }
 396                 if (token->special == '[' && lookup_type(token->next)) {
 397                         expr = alloc_expression(token->pos, EXPR_TYPE);
 398                         token = typename(token->next, &expr->symbol);
 399                         token = expect(token, ']', "in type expression");
 400                         break;
 401                 }
 402
 403         default:
 404                 ;
 405         }
 406         *tree = expr;
 407         return token;
 408 }
 409
 410 static struct token *expression_list(struct token *token, struct expression_list **list)
 411 {
 412         while (!match_op(token, ')')) {
 413                 struct expression *expr = NULL;
 414                 token = assignment_expression(token, &expr);
 415                 if (!expr)
 416                         break;
 417                 add_expression(list, expr);
 418                 if (!match_op(token, ','))
 419                         break;
 420                 token = token->next;
 421         }
 422         return token;
 423 }
 424
 425 /*
 426  * extend to deal with the ambiguous C grammar for parsing
 427  * a cast expressions followed by an initializer.
 428  */
 429 static struct token *postfix_expression(struct token *token, struct expression **tree, struct expression *cast_init_expr)
 430 {
 431         struct expression *expr = cast_init_expr;
 432
 433         if (!expr)
 434                 token = primary_expression(token, &expr);
 435
 436         while (expr && token_type(token) == TOKEN_SPECIAL) {
 437                 switch (token->special) {
 438                 case '[': {                     /* Array dereference */
 439                         struct expression *deref = alloc_expression(token->pos, EXPR_PREOP);
 440                         struct expression *add = alloc_expression(token->pos, EXPR_BINOP);
 441
 442                         deref->op = '*';
 443                         deref->unop = add;
 444
 445                         add->op = '+';
 446                         add->left = expr;
 447                         token = parse_expression(token->next, &add->right);
 448                         token = expect(token, ']', "at end of array dereference");
 449                         expr = deref;
 450                         continue;
 451                 }
 452                 case SPECIAL_INCREMENT:         /* Post-increment */
 453                 case SPECIAL_DECREMENT: {       /* Post-decrement */
 454                         struct expression *post = alloc_expression(token->pos, EXPR_POSTOP);
 455                         post->op = token->special;
 456                         post->unop = expr;
 457                         expr = post;
 458                         token = token->next;
 459                         continue;
 460                 }
 461                 case SPECIAL_DEREFERENCE: {     /* Structure pointer member dereference */
 462                         /* "x->y" is just shorthand for "(*x).y" */
 463                         struct expression *inner = alloc_expression(token->pos, EXPR_PREOP);
 464                         inner->op = '*';
 465                         inner->unop = expr;
 466                         expr = inner;
 467                 }
 468                 /* Fall through!! */
 469                 case '.': {                     /* Structure member dereference */
 470                         struct expression *deref = alloc_expression(token->pos, EXPR_DEREF);
 471                         deref->op = '.';
 472                         deref->deref = expr;
 473                         token = token->next;
 474                         if (token_type(token) != TOKEN_IDENT) {
 475                                 sparse_error(token->pos, "Expected member name");
 476                                 break;
 477                         }
 478                         deref->member = token->ident;
 479                         token = token->next;
 480                         expr = deref;
 481                         continue;
 482                 }
 483
 484                 case '(': {                     /* Function call */
 485                         struct expression *call = alloc_expression(token->pos, EXPR_CALL);
 486                         call->op = '(';
 487                         call->fn = expr;
 488                         token = expression_list(token->next, &call->args);
 489                         token = expect(token, ')', "in function call");
 490                         expr = call;
 491                         continue;
 492                 }
 493
 494                 default:
 495                         break;
 496                 }
 497                 break;
 498         }
 499         *tree = expr;
 500         return token;
 501 }
 502
 503 static struct token *cast_expression(struct token *token, struct expression **tree);
 504 static struct token *unary_expression(struct token *token, struct expression **tree);
 505
 506 static struct token *type_info_expression(struct token *token,
 507         struct expression **tree, int type)
 508 {
 509         struct expression *expr = alloc_expression(token->pos, type);
 510
 511         *tree = expr;
 512         token = token->next;
 513         if (!match_op(token, '(') || !lookup_type(token->next))
 514                 return unary_expression(token, &expr->cast_expression);
 515         token = typename(token->next, &expr->cast_type);
 516
 517         if (!match_op(token, ')')) {
 518                 static const char * error[] = {
 519                         [EXPR_SIZEOF] = "at end of sizeof",
 520                         [EXPR_ALIGNOF] = "at end of __alignof__",
 521                         [EXPR_PTRSIZEOF] = "at end of __sizeof_ptr__"
 522                 };
 523                 return expect(token, ')', error[type]);
 524         }
 525
 526         token = token->next;
 527         /*
 528          * C99 ambiguity: the typename might have been the beginning
 529          * of a typed initializer expression..
 530          */
 531         if (match_op(token, '{'))
 532                 token = initializer(&expr->cast_expression, token);
 533         return token;
 534 }
 535
 536 static struct token *unary_expression(struct token *token, struct expression **tree)
 537 {
 538         if (token_type(token) == TOKEN_IDENT) {
 539                 struct ident *ident = token->ident;
 540                 if (ident->reserved) {
 541                         static const struct {
 542                                 struct ident *id;
 543                                 int type;
 544                         } type_information[] = {
 545                                 { &sizeof_ident, EXPR_SIZEOF },
 546                                 { &__alignof___ident, EXPR_ALIGNOF },
 547                                 { &__alignof_ident, EXPR_ALIGNOF },
 548                                 { &__sizeof_ptr___ident, EXPR_PTRSIZEOF },
 549                         };
 550                         int i;
 551                         for (i = 0; i < 3; i++) {
 552                                 if (ident == type_information[i].id)
 553                                         return type_info_expression(token, tree, type_information[i].type);
 554                         }
 555                 }
 556         }
 557
 558         if (token_type(token) == TOKEN_SPECIAL) {
 559                 if (match_oplist(token->special,
 560                     SPECIAL_INCREMENT, SPECIAL_DECREMENT,
 561                     '&', '*', '+', '-', '~', '!', 0)) {
 562                         struct expression *unop;
 563                         struct expression *unary;
 564                         struct token *next;
 565
 566                         next = cast_expression(token->next, &unop);
 567                         if (!unop) {
 568                                 sparse_error(token->pos, "Syntax error in unary expression");
 569                                 return next;
 570                         }
 571                         unary = alloc_expression(token->pos, EXPR_PREOP);
 572                         unary->op = token->special;
 573                         unary->unop = unop;
 574                         *tree = unary;
 575                         return next;
 576                 }
 577
 578                 /* Gcc extension: &&label gives the address of a label */
 579                 if (match_op(token, SPECIAL_LOGICAL_AND) &&
 580                     token_type(token->next) == TOKEN_IDENT) {
 581                         struct expression *label = alloc_expression(token->pos, EXPR_LABEL);
 582                         struct symbol *sym = label_symbol(token->next);
 583                         if (!(sym->ctype.modifiers & MOD_ADDRESSABLE)) {
 584                                 sym->ctype.modifiers |= MOD_ADDRESSABLE;
 585                                 add_symbol(&function_computed_target_list, sym);
 586                         }
 587                         label->label_symbol = sym;
 588                         *tree = label;
 589                         return token->next->next;
 590                 }
 591
 592         }
 593
 594         return postfix_expression(token, tree, NULL);
 595 }
 596
 597 /*
 598  * Ambiguity: a '(' can be either a cast-expression or
 599  * a primary-expression depending on whether it is followed
 600  * by a type or not.
 601  *
 602  * additional ambiguity: a "cast expression" followed by
 603  * an initializer is really a postfix-expression.
 604  */
 605 static struct token *cast_expression(struct token *token, struct expression **tree)
 606 {
 607         if (match_op(token, '(')) {
 608                 struct token *next = token->next;
 609                 if (lookup_type(next)) {
 610                         struct expression *cast = alloc_expression(next->pos, EXPR_CAST);
 611                         struct symbol *sym;
 612
 613                         token = typename(next, &sym);
 614                         cast->cast_type = sym;
 615                         token = expect(token, ')', "at end of cast operator");
 616                         if (match_op(token, '{')) {
 617                                 token = initializer(&cast->cast_expression, token);
 618                                 return postfix_expression(token, tree, cast);
 619                         }
 620                         *tree = cast;
 621                         token = cast_expression(token, &cast->cast_expression);
 622                         return token;
 623                 }
 624         }
 625         return unary_expression(token, tree);
 626 }
 627
 628 /*
 629  * Generic left-to-right binop parsing
 630  *
 631  * This _really_ needs to be inlined, because that makes the inner
 632  * function call statically deterministic rather than a totally
 633  * unpredictable indirect call. But gcc-3 is so "clever" that it
 634  * doesn't do so by default even when you tell it to inline it.
 635  *
 636  * Making it a macro avoids the inlining problem, and also means
 637  * that we can pass in the op-comparison as an expression rather
 638  * than create a data structure for it.
 639  */
 640
 641 #define LR_BINOP_EXPRESSION(token, tree, type, inner, compare)          \
 642         struct expression *left = NULL;                                 \
 643         struct token * next = inner(token, &left);                      \
 644                                                                         \
 645         if (left) {                                                     \
 646                 while (token_type(next) == TOKEN_SPECIAL) {             \
 647                         struct expression *top, *right = NULL;          \
 648                         int op = next->special;                         \
 649                                                                         \
 650                         if (!(compare))                                 \
 651                                 goto out;                               \
 652                         top = alloc_expression(next->pos, type);        \
 653                         next = inner(next->next, &right);               \
 654                         if (!right) {                                   \
 655                                 sparse_error(next->pos, "No right hand side of '%s'-expression", show_special(op));     \
 656                                 break;                                  \
 657                         }                                               \
 658                         top->op = op;                                   \
 659                         top->left = left;                               \
 660                         top->right = right;                             \
 661                         left = top;                                     \
 662                 }                                                       \
 663         }                                                               \
 664 out:                                                                    \
 665         *tree = left;                                                   \
 666         return next;                                                    \
 667
 668
 669 static struct token *multiplicative_expression(struct token *token, struct expression **tree)
 670 {
 671         LR_BINOP_EXPRESSION(
 672                 token, tree, EXPR_BINOP, cast_expression,
 673                 (op == '*') || (op == '/') || (op == '%')
 674         );
 675 }
 676
 677 static struct token *additive_expression(struct token *token, struct expression **tree)
 678 {
 679         LR_BINOP_EXPRESSION(
 680                 token, tree, EXPR_BINOP, multiplicative_expression,
 681                 (op == '+') || (op == '-')
 682         );
 683 }
 684
 685 static struct token *shift_expression(struct token *token, struct expression **tree)
 686 {
 687         LR_BINOP_EXPRESSION(
 688                 token, tree, EXPR_BINOP, additive_expression,
 689                 (op == SPECIAL_LEFTSHIFT) || (op == SPECIAL_RIGHTSHIFT)
 690         );
 691 }
 692
 693 static struct token *relational_expression(struct token *token, struct expression **tree)
 694 {
 695         LR_BINOP_EXPRESSION(
 696                 token, tree, EXPR_COMPARE, shift_expression,
 697                 (op == '<') || (op == '>') ||
 698                 (op == SPECIAL_LTE) || (op == SPECIAL_GTE)
 699         );
 700 }
 701
 702 static struct token *equality_expression(struct token *token, struct expression **tree)
 703 {
 704         LR_BINOP_EXPRESSION(
 705                 token, tree, EXPR_COMPARE, relational_expression,
 706                 (op == SPECIAL_EQUAL) || (op == SPECIAL_NOTEQUAL)
 707         );
 708 }
 709
 710 static struct token *bitwise_and_expression(struct token *token, struct expression **tree)
 711 {
 712         LR_BINOP_EXPRESSION(
 713                 token, tree, EXPR_BINOP, equality_expression,
 714                 (op == '&')
 715         );
 716 }
 717
 718 static struct token *bitwise_xor_expression(struct token *token, struct expression **tree)
 719 {
 720         LR_BINOP_EXPRESSION(
 721                 token, tree, EXPR_BINOP, bitwise_and_expression,
 722                 (op == '^')
 723         );
 724 }
 725
 726 static struct token *bitwise_or_expression(struct token *token, struct expression **tree)
 727 {
 728         LR_BINOP_EXPRESSION(
 729                 token, tree, EXPR_BINOP, bitwise_xor_expression,
 730                 (op == '|')
 731         );
 732 }
 733
 734 static struct token *logical_and_expression(struct token *token, struct expression **tree)
 735 {
 736         LR_BINOP_EXPRESSION(
 737                 token, tree, EXPR_LOGICAL, bitwise_or_expression,
 738                 (op == SPECIAL_LOGICAL_AND)
 739         );
 740 }
 741
 742 static struct token *logical_or_expression(struct token *token, struct expression **tree)
 743 {
 744         LR_BINOP_EXPRESSION(
 745                 token, tree, EXPR_LOGICAL, logical_and_expression,
 746                 (op == SPECIAL_LOGICAL_OR)
 747         );
 748 }
 749
 750 struct token *conditional_expression(struct token *token, struct expression **tree)
 751 {
 752         token = logical_or_expression(token, tree);
 753         if (*tree && match_op(token, '?')) {
 754                 struct expression *expr = alloc_expression(token->pos, EXPR_CONDITIONAL);
 755                 expr->op = token->special;
 756                 expr->left = *tree;
 757                 *tree = expr;
 758                 token = parse_expression(token->next, &expr->cond_true);
 759                 token = expect(token, ':', "in conditional expression");
 760                 token = conditional_expression(token, &expr->cond_false);
 761         }
 762         return token;
 763 }
 764
 765 struct token *assignment_expression(struct token *token, struct expression **tree)
 766 {
 767         token = conditional_expression(token, tree);
 768         if (*tree && token_type(token) == TOKEN_SPECIAL) {
 769                 static const int assignments[] = {
 770                         '=',
 771                         SPECIAL_ADD_ASSIGN, SPECIAL_SUB_ASSIGN,
 772                         SPECIAL_MUL_ASSIGN, SPECIAL_DIV_ASSIGN,
 773                         SPECIAL_MOD_ASSIGN, SPECIAL_SHL_ASSIGN,
 774                         SPECIAL_SHR_ASSIGN, SPECIAL_AND_ASSIGN,
 775                         SPECIAL_OR_ASSIGN,  SPECIAL_XOR_ASSIGN };
 776                 int i, op = token->special;
 777                 for (i = 0; i < sizeof(assignments)/sizeof(int); i++)
 778                         if (assignments[i] == op) {
 779                                 struct expression * expr = alloc_expression(token->pos, EXPR_ASSIGNMENT);
 780                                 expr->left = *tree;
 781                                 expr->op = op;
 782                                 *tree = expr;
 783                                 return assignment_expression(token->next, &expr->right);
 784                         }
 785         }
 786         return token;
 787 }
 788
 789 static struct token *comma_expression(struct token *token, struct expression **tree)
 790 {
 791         LR_BINOP_EXPRESSION(
 792                 token, tree, EXPR_COMMA, assignment_expression,
 793                 (op == ',')
 794         );
 795 }
 796
 797 struct token *parse_expression(struct token *token, struct expression **tree)
 798 {
 799         return comma_expression(token,tree);
 800 }
 801
 802