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implied: remove some dead code
[smatch.git] / expression.c
blob122d7e532ddd0b5a46879388ce7aa6edff505875
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 ALLOCATOR(type_expression, "type-expr-maps");
48
49 static int match_oplist(int op, ...)
50 {
51 va_list args;
52 int nextop;
53
54 va_start(args, op);
55 do {
56 nextop = va_arg(args, int);
57 } while (nextop != 0 && nextop != op);
58 va_end(args);
59
60 return nextop != 0;
61 }
62
63 static struct token *comma_expression(struct token *, struct expression **);
64
65 struct token *parens_expression(struct token *token, struct expression **expr, const char *where)
66 {
67 struct token *p;
68
69 token = expect(token, '(', where);
70 p = token;
71 if (match_op(token, '{')) {
72 struct expression *e = alloc_expression(token->pos, EXPR_STATEMENT);
73 struct statement *stmt = alloc_statement(token->pos, STMT_COMPOUND);
74 *expr = e;
75 e->statement = stmt;
76 start_label_scope(token->pos);
77 token = compound_statement(token->next, stmt);
78 end_label_scope();
79 token = expect(token, '}', "at end of statement expression");
80 } else
81 token = parse_expression(token, expr);
82
83 if (token == p)
84 sparse_error(token->pos, "an expression is expected before ')'");
85 return expect(token, ')', where);
86 }
87
88 struct token *string_expression(struct token *token, struct expression **expr, const char *where)
89 {
90 struct token *next = primary_expression(token, expr);
91
92 if (!*expr || (*expr)->type != EXPR_STRING) {
93 sparse_error(token->pos, "string literal expected for %s", where);
94 *expr = NULL;
95 }
96 return next;
97 }
98
99 /*
100 * Handle __func__, __FUNCTION__ and __PRETTY_FUNCTION__ token
101 * conversion
102 */
103 static struct symbol *handle_func(struct token *token)
104 {
105 struct ident *ident = token->ident;
106 struct symbol *decl, *array;
107 struct string *string;
108 int len;
109
110 if (ident != &__func___ident &&
111 ident != &__FUNCTION___ident &&
112 ident != &__PRETTY_FUNCTION___ident)
113 return NULL;
114
115 if (!current_fn || !current_fn->ident)
116 return NULL;
117
118 /* OK, it's one of ours */
119 array = alloc_symbol(token->pos, SYM_ARRAY);
120 array->ctype.base_type = &char_ctype;
121 array->ctype.alignment = 1;
122 array->endpos = token->pos;
123 decl = alloc_symbol(token->pos, SYM_NODE);
124 decl->ctype.base_type = array;
125 decl->ctype.alignment = 1;
126 decl->ctype.modifiers = MOD_STATIC;
127 decl->endpos = token->pos;
128
129 /* NS_SYMBOL but in function-scope */
130 bind_symbol_with_scope(decl, ident, NS_SYMBOL, function_scope);
131
132 len = current_fn->ident->len;
133 string = __alloc_string(len + 1);
134 memcpy(string->data, current_fn->ident->name, len);
135 string->data[len] = 0;
136 string->length = len + 1;
137
138 decl->initializer = alloc_expression(token->pos, EXPR_STRING);
139 decl->initializer->string = string;
140 decl->initializer->ctype = decl;
141 decl->array_size = alloc_const_expression(token->pos, len + 1);
142 array->array_size = decl->array_size;
143 decl->bit_size = array->bit_size = bytes_to_bits(len + 1);
144
145 return decl;
146 }
147
148 static struct token *parse_type(struct token *token, struct expression **tree)
149 {
150 struct symbol *sym;
151 *tree = alloc_expression(token->pos, EXPR_TYPE);
152 token = typename(token, &sym, NULL);
153 if (sym->ident)
154 sparse_error(token->pos,
155 "type expression should not include identifier "
156 "\"%s\"", sym->ident->name);
157 (*tree)->symbol = sym;
158 return token;
159 }
160
161 static struct token *builtin_types_compatible_p_expr(struct token *token,
162 struct expression **tree)
163 {
164 struct expression *expr = alloc_expression(
165 token->pos, EXPR_COMPARE);
166 expr->op = SPECIAL_EQUAL;
167 token = token->next;
168 if (!match_op(token, '('))
169 return expect(token, '(',
170 "after __builtin_types_compatible_p");
171 token = token->next;
172 token = parse_type(token, &expr->left);
173 if (!match_op(token, ','))
174 return expect(token, ',',
175 "in __builtin_types_compatible_p");
176 token = token->next;
177 token = parse_type(token, &expr->right);
178 if (!match_op(token, ')'))
179 return expect(token, ')',
180 "at end of __builtin_types_compatible_p");
181 token = token->next;
182
183 *tree = expr;
184 return token;
185 }
186
187 static struct token *builtin_offsetof_expr(struct token *token,
188 struct expression **tree)
189 {
190 struct expression *expr = NULL;
191 struct expression **p = &expr;
192 struct symbol *sym;
193 int op = '.';
194
195 token = token->next;
196 if (!match_op(token, '('))
197 return expect(token, '(', "after __builtin_offset");
198
199 token = token->next;
200 token = typename(token, &sym, NULL);
201 if (sym->ident)
202 sparse_error(token->pos,
203 "type expression should not include identifier "
204 "\"%s\"", sym->ident->name);
205
206 if (!match_op(token, ','))
207 return expect(token, ',', "in __builtin_offset");
208
209 while (1) {
210 struct expression *e;
211 switch (op) {
212 case ')':
213 expr->in = sym;
214 *tree = expr;
215 default:
216 return expect(token, ')', "at end of __builtin_offset");
217 case SPECIAL_DEREFERENCE:
218 e = alloc_expression(token->pos, EXPR_OFFSETOF);
219 e->op = '[';
220 *p = e;
221 p = &e->down;
222 /* fall through */
223 case '.':
224 token = token->next;
225 e = alloc_expression(token->pos, EXPR_OFFSETOF);
226 e->op = '.';
227 if (token_type(token) != TOKEN_IDENT) {
228 sparse_error(token->pos, "Expected member name");
229 return token;
230 }
231 e->ident = token->ident;
232 token = token->next;
233 break;
234 case '[':
235 token = token->next;
236 e = alloc_expression(token->pos, EXPR_OFFSETOF);
237 e->op = '[';
238 token = parse_expression(token, &e->index);
239 token = expect(token, ']',
240 "at end of array dereference");
241 if (!e->index)
242 return token;
243 }
244 *p = e;
245 p = &e->down;
246 op = token_type(token) == TOKEN_SPECIAL ? token->special : 0;
247 }
248 }
249
250 #ifndef ULLONG_MAX
251 #define ULLONG_MAX (~0ULL)
252 #endif
253
254 static unsigned long long parse_num(const char *nptr, char **end)
255 {
256 if (nptr[0] == '0' && tolower((unsigned char)nptr[1]) == 'b')
257 return strtoull(&nptr[2], end, 2);
258 return strtoull(nptr, end, 0);
259 }
260
261 static void get_number_value(struct expression *expr, struct token *token)
262 {
263 const char *str = token->number;
264 unsigned long long value;
265 char *end;
266 int size = 0, want_unsigned = 0;
267 int overflow = 0, do_warn = 0;
268 int try_unsigned = 1;
269 int bits;
270
271 errno = 0;
272 value = parse_num(str, &end);
273 if (end == str)
274 goto Float;
275 if (value == ULLONG_MAX && errno == ERANGE)
276 overflow = 1;
277 while (1) {
278 char c = *end++;
279 if (!c) {
280 break;
281 } else if (c == 'u' || c == 'U') {
282 if (want_unsigned)
283 goto Enoint;
284 want_unsigned = 1;
285 } else if (c == 'l' || c == 'L') {
286 if (size)
287 goto Enoint;
288 size = 1;
289 if (*end == c) {
290 size = 2;
291 end++;
292 }
293 } else
294 goto Float;
295 }
296 if (overflow)
297 goto Eoverflow;
298 /* OK, it's a valid integer */
299 /* decimals can be unsigned only if directly specified as such */
300 if (str[0] != '0' && !want_unsigned)
301 try_unsigned = 0;
302 if (!size) {
303 bits = bits_in_int - 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 }
312 size = 1;
313 do_warn = 1;
314 }
315 if (size < 2) {
316 bits = bits_in_long - 1;
317 if (!(value & (~1ULL << bits))) {
318 if (!(value & (1ULL << bits))) {
319 goto got_it;
320 } else if (try_unsigned) {
321 want_unsigned = 1;
322 goto got_it;
323 }
324 do_warn |= 2;
325 }
326 size = 2;
327 do_warn |= 1;
328 }
329 bits = bits_in_longlong - 1;
330 if (value & (~1ULL << bits))
331 goto Eoverflow;
332 if (!(value & (1ULL << bits)))
333 goto got_it;
334 if (!try_unsigned)
335 warning(expr->pos, "decimal constant %s is too big for long long",
336 show_token(token));
337 want_unsigned = 1;
338 got_it:
339 if (do_warn && Wconstant_suffix)
340 warning(expr->pos, "constant %s is so big it is%s%s%s",
341 show_token(token),
342 want_unsigned ? " unsigned":"",
343 size > 0 ? " long":"",
344 size > 1 ? " long":"");
345 if (do_warn & 2)
346 warning(expr->pos,
347 "decimal constant %s is between LONG_MAX and ULONG_MAX."
348 " For C99 that means long long, C90 compilers are very "
349 "likely to produce unsigned long (and a warning) here",
350 show_token(token));
351 expr->type = EXPR_VALUE;
352 expr->flags = CEF_SET_INT;
353 expr->ctype = ctype_integer(size, want_unsigned);
354 expr->value = value;
355 return;
356 Eoverflow:
357 error_die(expr->pos, "constant %s is too big even for unsigned long long",
358 show_token(token));
359 return;
360 Float:
361 expr->fvalue = string_to_ld(str, &end);
362 if (str == end)
363 goto Enoint;
364
365 if (*end && end[1])
366 goto Enoint;
367
368 if (*end == 'f' || *end == 'F')
369 expr->ctype = &float_ctype;
370 else if (*end == 'l' || *end == 'L')
371 expr->ctype = &ldouble_ctype;
372 else if (!*end)
373 expr->ctype = &double_ctype;
374 else
375 goto Enoint;
376
377 expr->flags = CEF_SET_FLOAT;
378 expr->type = EXPR_FVALUE;
379 return;
380
381 Enoint:
382 sparse_error(expr->pos, "constant %s is not a valid number", show_token(token));
383 expr->type = EXPR_VALUE;
384 expr->value = 0;
385 expr->ctype = &int_ctype;
386 }
387
388 static struct token *generic_selection(struct token *token, struct expression **tree)
389 {
390 struct expression *expr = alloc_expression(token->pos, EXPR_GENERIC);
391 struct type_expression **last = &expr->map;
392
393 token = expect(token, '(', "after '_Generic'");
394 token = assignment_expression(token, &expr->control);
395 if (!match_op(token, ',')) {
396 goto end;
397 }
398 while (match_op(token, ',')) {
399 token = token->next;
400 if (lookup_type(token)) {
401 struct type_expression *map = __alloc_type_expression(0);
402 token = typename(token, &map->type, NULL);
403 token = expect(token, ':', "after typename");
404 token = assignment_expression(token, &map->expr);
405 *last = map;
406 last = &map->next;
407 } else if (match_ident(token, &default_ident)) {
408 if (expr->def) {
409 warning(token->pos, "multiple default in generic expression");
410 info(expr->def->pos, "note: previous was here");
411 }
412 token = token->next;
413 token = expect(token, ':', "after typename");
414 token = assignment_expression(token, &expr->def);
415 }
416 }
417 end:
418 *tree = expr;
419 return expect(token, ')', "after expression");
420 }
421
422 struct token *primary_expression(struct token *token, struct expression **tree)
423 {
424 struct expression *expr = NULL;
425
426 switch (token_type(token)) {
427 case TOKEN_CHAR ... TOKEN_WIDE_CHAR_EMBEDDED_3:
428 expr = alloc_expression(token->pos, EXPR_VALUE);
429 expr->flags = CEF_SET_CHAR;
430 get_char_constant(token, &expr->value);
431
432 // TODO: handle 'u8', 'u' & 'U' prefixes.
433 if (token_type(token) < TOKEN_WIDE_CHAR) {
434 expr->ctype = &char_ctype;
435 cast_value(expr, &int_ctype, expr);
436 } else {
437 expr->ctype = wchar_ctype;
438 }
439 token = token->next;
440 break;
441
442 case TOKEN_NUMBER:
443 expr = alloc_expression(token->pos, EXPR_VALUE);
444 get_number_value(expr, token); /* will see if it's an integer */
445 token = token->next;
446 break;
447
448 case TOKEN_ZERO_IDENT: {
449 expr = alloc_expression(token->pos, EXPR_SYMBOL);
450 expr->flags = CEF_SET_INT;
451 expr->ctype = &int_ctype;
452 expr->symbol = &zero_int;
453 expr->symbol_name = token->ident;
454 token = token->next;
455 break;
456 }
457
458 case TOKEN_IDENT: {
459 struct symbol *sym = lookup_symbol(token->ident, NS_SYMBOL | NS_TYPEDEF);
460 struct token *next = token->next;
461
462 if (!sym) {
463 sym = handle_func(token);
464 if (token->ident == &__builtin_types_compatible_p_ident) {
465 token = builtin_types_compatible_p_expr(token, &expr);
466 break;
467 }
468 if (token->ident == &__builtin_offsetof_ident) {
469 token = builtin_offsetof_expr(token, &expr);
470 break;
471 }
472 if (token->ident == &_Generic_ident) {
473 token = generic_selection(token->next, &expr);
474 break;
475 }
476 } else if (sym->enum_member) {
477 expr = alloc_expression(token->pos, EXPR_VALUE);
478 *expr = *sym->initializer;
479 /* we want the right position reported, thus the copy */
480 expr->pos = token->pos;
481 expr->flags = CEF_SET_ENUM;
482 token = next;
483 break;
484 }
485
486 expr = alloc_expression(token->pos, EXPR_SYMBOL);
487
488 /*
489 * We support types as real first-class citizens, with type
490 * comparisons etc:
491 *
492 * if (typeof(a) == int) ..
493 */
494 if (sym && sym->namespace == NS_TYPEDEF) {
495 sparse_error(token->pos, "typename in expression");
496 sym = NULL;
497 }
498 expr->symbol_name = token->ident;
499 expr->symbol = sym;
500
501 /*
502 * A pointer to an lvalue designating a static storage
503 * duration object is an address constant [6.6(9)].
504 */
505 if (sym && (sym->ctype.modifiers & (MOD_TOPLEVEL | MOD_STATIC)))
506 expr->flags = CEF_ADDR;
507
508 token = next;
509 break;
510 }
511
512 case TOKEN_STRING:
513 case TOKEN_WIDE_STRING:
514 expr = alloc_expression(token->pos, EXPR_STRING);
515 token = get_string_constant(token, expr);
516 break;
517
518 case TOKEN_SPECIAL:
519 if (token->special == '(') {
520 expr = alloc_expression(token->pos, EXPR_PREOP);
521 expr->op = '(';
522 token = parens_expression(token, &expr->unop, "in expression");
523 break;
524 }
525 if (token->special == '[' && lookup_type(token->next)) {
526 expr = alloc_expression(token->pos, EXPR_TYPE);
527 token = typename(token->next, &expr->symbol, NULL);
528 token = expect(token, ']', "in type expression");
529 break;
530 }
531
532 default:
533 ;
534 }
535 *tree = expr;
536 return token;
537 }
538
539 static struct token *expression_list(struct token *token, struct expression_list **list)
540 {
541 while (!match_op(token, ')')) {
542 struct expression *expr = NULL;
543 token = assignment_expression(token, &expr);
544 if (!expr)
545 break;
546 add_expression(list, expr);
547 if (!match_op(token, ','))
548 break;
549 token = token->next;
550 }
551 return token;
552 }
553
554 /*
555 * extend to deal with the ambiguous C grammar for parsing
556 * a cast expressions followed by an initializer.
557 */
558 static struct token *postfix_expression(struct token *token, struct expression **tree, struct expression *cast_init_expr)
559 {
560 struct expression *expr = cast_init_expr;
561
562 if (!expr)
563 token = primary_expression(token, &expr);
564
565 while (expr && token_type(token) == TOKEN_SPECIAL) {
566 switch (token->special) {
567 case '[': { /* Array dereference */
568 struct expression *deref = alloc_expression(token->pos, EXPR_PREOP);
569 struct expression *add = alloc_expression(token->pos, EXPR_BINOP);
570
571 deref->op = '*';
572 deref->unop = add;
573
574 add->op = '+';
575 add->left = expr;
576 token = parse_expression(token->next, &add->right);
577 token = expect(token, ']', "at end of array dereference");
578 expr = deref;
579 continue;
580 }
581 case SPECIAL_INCREMENT: /* Post-increment */
582 case SPECIAL_DECREMENT: { /* Post-decrement */
583 struct expression *post = alloc_expression(token->pos, EXPR_POSTOP);
584 post->op = token->special;
585 post->unop = expr;
586 expr = post;
587 token = token->next;
588 continue;
589 }
590 case SPECIAL_DEREFERENCE: { /* Structure pointer member dereference */
591 /* "x->y" is just shorthand for "(*x).y" */
592 struct expression *inner = alloc_expression(token->pos, EXPR_PREOP);
593 inner->op = '*';
594 inner->unop = expr;
595 expr = inner;
596 }
597 /* Fall through!! */
598 case '.': { /* Structure member dereference */
599 struct expression *deref = alloc_expression(token->pos, EXPR_DEREF);
600 deref->op = '.';
601 deref->deref = expr;
602 token = token->next;
603 if (token_type(token) != TOKEN_IDENT) {
604 sparse_error(token->pos, "Expected member name");
605 break;
606 }
607 deref->member = token->ident;
608 deref->member_offset = -1;
609 token = token->next;
610 expr = deref;
611 continue;
612 }
613
614 case '(': { /* Function call */
615 struct expression *call = alloc_expression(token->pos, EXPR_CALL);
616 call->op = '(';
617 call->fn = expr;
618 token = expression_list(token->next, &call->args);
619 token = expect(token, ')', "in function call");
620 expr = call;
621 continue;
622 }
623
624 default:
625 break;
626 }
627 break;
628 }
629 *tree = expr;
630 return token;
631 }
632
633 static struct token *cast_expression(struct token *token, struct expression **tree);
634 static struct token *unary_expression(struct token *token, struct expression **tree);
635
636 static struct token *type_info_expression(struct token *token,
637 struct expression **tree, int type)
638 {
639 struct expression *expr = alloc_expression(token->pos, type);
640 struct token *p;
641
642 *tree = expr;
643 expr->flags = CEF_SET_ICE; /* XXX: VLA support will need that changed */
644 token = token->next;
645 if (!match_op(token, '(') || !lookup_type(token->next))
646 return unary_expression(token, &expr->cast_expression);
647 p = token;
648 token = typename(token->next, &expr->cast_type, NULL);
649
650 if (!match_op(token, ')')) {
651 static const char * error[] = {
652 [EXPR_SIZEOF] = "at end of sizeof",
653 [EXPR_ALIGNOF] = "at end of __alignof__",
654 [EXPR_PTRSIZEOF] = "at end of __sizeof_ptr__"
655 };
656 return expect(token, ')', error[type]);
657 }
658
659 token = token->next;
660 /*
661 * C99 ambiguity: the typename might have been the beginning
662 * of a typed initializer expression..
663 */
664 if (match_op(token, '{')) {
665 struct expression *cast = alloc_expression(p->pos, EXPR_CAST);
666 cast->cast_type = expr->cast_type;
667 expr->cast_type = NULL;
668 expr->cast_expression = cast;
669 token = initializer(&cast->cast_expression, token);
670 token = postfix_expression(token, &expr->cast_expression, cast);
671 }
672 return token;
673 }
674
675 static struct token *unary_expression(struct token *token, struct expression **tree)
676 {
677 if (token_type(token) == TOKEN_IDENT) {
678 struct ident *ident = token->ident;
679 if (ident->reserved) {
680 static const struct {
681 struct ident *id;
682 int type;
683 } type_information[] = {
684 { &sizeof_ident, EXPR_SIZEOF },
685 { &__alignof___ident, EXPR_ALIGNOF },
686 { &__alignof_ident, EXPR_ALIGNOF },
687 { &_Alignof_ident, EXPR_ALIGNOF },
688 { &__sizeof_ptr___ident, EXPR_PTRSIZEOF },
689 };
690 int i;
691 for (i = 0; i < ARRAY_SIZE(type_information); i++) {
692 if (ident == type_information[i].id)
693 return type_info_expression(token, tree, type_information[i].type);
694 }
695 }
696 }
697
698 if (token_type(token) == TOKEN_SPECIAL) {
699 if (match_oplist(token->special,
700 SPECIAL_INCREMENT, SPECIAL_DECREMENT,
701 '&', '*', 0)) {
702 struct expression *unop;
703 struct expression *unary;
704 struct token *next;
705
706 next = cast_expression(token->next, &unop);
707 if (!unop) {
708 sparse_error(token->pos, "Syntax error in unary expression");
709 *tree = NULL;
710 return next;
711 }
712 unary = alloc_expression(token->pos, EXPR_PREOP);
713 unary->op = token->special;
714 unary->unop = unop;
715 *tree = unary;
716 return next;
717 }
718 /* possibly constant ones */
719 if (match_oplist(token->special, '+', '-', '~', '!', 0)) {
720 struct expression *unop;
721 struct expression *unary;
722 struct token *next;
723
724 next = cast_expression(token->next, &unop);
725 if (!unop) {
726 sparse_error(token->pos, "Syntax error in unary expression");
727 *tree = NULL;
728 return next;
729 }
730 unary = alloc_expression(token->pos, EXPR_PREOP);
731 unary->op = token->special;
732 unary->unop = unop;
733 *tree = unary;
734 return next;
735 }
736 /* Gcc extension: &&label gives the address of a label */
737 if (match_op(token, SPECIAL_LOGICAL_AND) &&
738 token_type(token->next) == TOKEN_IDENT) {
739 struct expression *label = alloc_expression(token->pos, EXPR_LABEL);
740 struct symbol *sym = label_symbol(token->next, 1);
741 if (!(sym->ctype.modifiers & MOD_ADDRESSABLE)) {
742 sym->ctype.modifiers |= MOD_ADDRESSABLE;
743 add_symbol(&function_computed_target_list, sym);
744 }
745 check_label_usage(sym, token->pos);
746 label->flags = CEF_ADDR;
747 label->label_symbol = sym;
748 *tree = label;
749 return token->next->next;
750 }
751
752 }
753
754 return postfix_expression(token, tree, NULL);
755 }
756
757 /*
758 * Ambiguity: a '(' can be either a cast-expression or
759 * a primary-expression depending on whether it is followed
760 * by a type or not.
761 *
762 * additional ambiguity: a "cast expression" followed by
763 * an initializer is really a postfix-expression.
764 */
765 static struct token *cast_expression(struct token *token, struct expression **tree)
766 {
767 if (match_op(token, '(')) {
768 struct token *next = token->next;
769 if (lookup_type(next)) {
770 struct expression *cast = alloc_expression(next->pos, EXPR_CAST);
771 struct expression *v;
772 struct symbol *sym;
773 int is_force;
774
775 token = typename(next, &sym, &is_force);
776 cast->cast_type = sym;
777 token = expect(token, ')', "at end of cast operator");
778 if (match_op(token, '{')) {
779 if (toplevel(block_scope))
780 sym->ctype.modifiers |= MOD_TOPLEVEL;
781 if (is_force)
782 warning(sym->pos,
783 "[force] in compound literal");
784 token = initializer(&cast->cast_expression, token);
785 return postfix_expression(token, tree, cast);
786 }
787 *tree = cast;
788 if (is_force)
789 cast->type = EXPR_FORCE_CAST;
790 token = cast_expression(token, &v);
791 if (!v)
792 return token;
793 cast->cast_expression = v;
794 return token;
795 }
796 }
797 return unary_expression(token, tree);
798 }
799
800 /*
801 * Generic left-to-right binop parsing
802 *
803 * This _really_ needs to be inlined, because that makes the inner
804 * function call statically deterministic rather than a totally
805 * unpredictable indirect call. But gcc-3 is so "clever" that it
806 * doesn't do so by default even when you tell it to inline it.
807 *
808 * Making it a macro avoids the inlining problem, and also means
809 * that we can pass in the op-comparison as an expression rather
810 * than create a data structure for it.
811 */
812
813 #define LR_BINOP_EXPRESSION(__token, tree, type, inner, compare) \
814 struct expression *left = NULL; \
815 struct token * next = inner(__token, &left); \
816 \
817 if (left) { \
818 while (token_type(next) == TOKEN_SPECIAL) { \
819 struct expression *top, *right = NULL; \
820 int op = next->special; \
821 \
822 if (!(compare)) \
823 goto out; \
824 top = alloc_expression(next->pos, type); \
825 next = inner(next->next, &right); \
826 if (!right) { \
827 sparse_error(next->pos, "No right hand side of '%s'-expression", show_special(op)); \
828 break; \
829 } \
830 top->op = op; \
831 top->left = left; \
832 top->right = right; \
833 left = top; \
834 } \
835 } \
836 out: \
837 *tree = left; \
838 return next; \
839
840 static struct token *multiplicative_expression(struct token *token, struct expression **tree)
841 {
842 LR_BINOP_EXPRESSION(
843 token, tree, EXPR_BINOP, cast_expression,
844 (op == '*') || (op == '/') || (op == '%')
845 );
846 }
847
848 static struct token *additive_expression(struct token *token, struct expression **tree)
849 {
850 LR_BINOP_EXPRESSION(
851 token, tree, EXPR_BINOP, multiplicative_expression,
852 (op == '+') || (op == '-')
853 );
854 }
855
856 static struct token *shift_expression(struct token *token, struct expression **tree)
857 {
858 LR_BINOP_EXPRESSION(
859 token, tree, EXPR_BINOP, additive_expression,
860 (op == SPECIAL_LEFTSHIFT) || (op == SPECIAL_RIGHTSHIFT)
861 );
862 }
863
864 static struct token *relational_expression(struct token *token, struct expression **tree)
865 {
866 LR_BINOP_EXPRESSION(
867 token, tree, EXPR_COMPARE, shift_expression,
868 (op == '<') || (op == '>') ||
869 (op == SPECIAL_LTE) || (op == SPECIAL_GTE)
870 );
871 }
872
873 static struct token *equality_expression(struct token *token, struct expression **tree)
874 {
875 LR_BINOP_EXPRESSION(
876 token, tree, EXPR_COMPARE, relational_expression,
877 (op == SPECIAL_EQUAL) || (op == SPECIAL_NOTEQUAL)
878 );
879 }
880
881 static struct token *bitwise_and_expression(struct token *token, struct expression **tree)
882 {
883 LR_BINOP_EXPRESSION(
884 token, tree, EXPR_BINOP, equality_expression,
885 (op == '&')
886 );
887 }
888
889 static struct token *bitwise_xor_expression(struct token *token, struct expression **tree)
890 {
891 LR_BINOP_EXPRESSION(
892 token, tree, EXPR_BINOP, bitwise_and_expression,
893 (op == '^')
894 );
895 }
896
897 static struct token *bitwise_or_expression(struct token *token, struct expression **tree)
898 {
899 LR_BINOP_EXPRESSION(
900 token, tree, EXPR_BINOP, bitwise_xor_expression,
901 (op == '|')
902 );
903 }
904
905 static struct token *logical_and_expression(struct token *token, struct expression **tree)
906 {
907 LR_BINOP_EXPRESSION(
908 token, tree, EXPR_LOGICAL, bitwise_or_expression,
909 (op == SPECIAL_LOGICAL_AND)
910 );
911 }
912
913 static struct token *logical_or_expression(struct token *token, struct expression **tree)
914 {
915 LR_BINOP_EXPRESSION(
916 token, tree, EXPR_LOGICAL, logical_and_expression,
917 (op == SPECIAL_LOGICAL_OR)
918 );
919 }
920
921 struct token *conditional_expression(struct token *token, struct expression **tree)
922 {
923 token = logical_or_expression(token, tree);
924 if (*tree && match_op(token, '?')) {
925 struct expression *expr = alloc_expression(token->pos, EXPR_CONDITIONAL);
926 expr->op = token->special;
927 expr->conditional = *tree;
928 *tree = expr;
929 token = parse_expression(token->next, &expr->cond_true);
930 token = expect(token, ':', "in conditional expression");
931 token = conditional_expression(token, &expr->cond_false);
932 }
933 return token;
934 }
935
936 struct token *assignment_expression(struct token *token, struct expression **tree)
937 {
938 token = conditional_expression(token, tree);
939 if (*tree && token_type(token) == TOKEN_SPECIAL) {
940 static const int assignments[] = {
941 '=',
942 SPECIAL_ADD_ASSIGN, SPECIAL_SUB_ASSIGN,
943 SPECIAL_MUL_ASSIGN, SPECIAL_DIV_ASSIGN,
944 SPECIAL_MOD_ASSIGN, SPECIAL_SHL_ASSIGN,
945 SPECIAL_SHR_ASSIGN, SPECIAL_AND_ASSIGN,
946 SPECIAL_OR_ASSIGN, SPECIAL_XOR_ASSIGN };
947 int i, op = token->special;
948 for (i = 0; i < ARRAY_SIZE(assignments); i++)
949 if (assignments[i] == op) {
950 struct expression * expr = alloc_expression(token->pos, EXPR_ASSIGNMENT);
951 struct token *next = token->next;
952 expr->left = *tree;
953 expr->op = op;
954 *tree = expr;
955 token = assignment_expression(next, &expr->right);
956 if (token == next)
957 expression_error(expr, "expression expected before '%s'", show_token(token));
958 return token;
959 }
960 }
961 return token;
962 }
963
964 static struct token *comma_expression(struct token *token, struct expression **tree)
965 {
966 LR_BINOP_EXPRESSION(
967 token, tree, EXPR_COMMA, assignment_expression,
968 (op == ',')
969 );
970 }
971
972 struct token *parse_expression(struct token *token, struct expression **tree)
973 {
974 return comma_expression(token,tree);
975 }
976
977
Static analysis for C