?  search:
summary | log | graphiclog1 | graphiclog2 | commit | commitdiff | tree | refs | edit | fork
blame | history | raw | HEAD
rosenberg: handle bit fields better
[smatch.git] / expression.c
blob3d2c727f8cfe025ceb42cef1c35064de74752ee9
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 expr->ctype = token_type(token) < TOKEN_WIDE_CHAR ? &int_ctype : &long_ctype;
431 get_char_constant(token, &expr->value);
432 token = token->next;
433 break;
434
435 case TOKEN_NUMBER:
436 expr = alloc_expression(token->pos, EXPR_VALUE);
437 get_number_value(expr, token); /* will see if it's an integer */
438 token = token->next;
439 break;
440
441 case TOKEN_ZERO_IDENT: {
442 expr = alloc_expression(token->pos, EXPR_SYMBOL);
443 expr->flags = CEF_SET_INT;
444 expr->ctype = &int_ctype;
445 expr->symbol = &zero_int;
446 expr->symbol_name = token->ident;
447 token = token->next;
448 break;
449 }
450
451 case TOKEN_IDENT: {
452 struct symbol *sym = lookup_symbol(token->ident, NS_SYMBOL | NS_TYPEDEF);
453 struct token *next = token->next;
454
455 if (!sym) {
456 sym = handle_func(token);
457 if (token->ident == &__builtin_types_compatible_p_ident) {
458 token = builtin_types_compatible_p_expr(token, &expr);
459 break;
460 }
461 if (token->ident == &__builtin_offsetof_ident) {
462 token = builtin_offsetof_expr(token, &expr);
463 break;
464 }
465 if (token->ident == &_Generic_ident) {
466 token = generic_selection(token->next, &expr);
467 break;
468 }
469 } else if (sym->enum_member) {
470 expr = alloc_expression(token->pos, EXPR_VALUE);
471 *expr = *sym->initializer;
472 /* we want the right position reported, thus the copy */
473 expr->pos = token->pos;
474 expr->flags = CEF_SET_ENUM;
475 token = next;
476 break;
477 }
478
479 expr = alloc_expression(token->pos, EXPR_SYMBOL);
480
481 /*
482 * We support types as real first-class citizens, with type
483 * comparisons etc:
484 *
485 * if (typeof(a) == int) ..
486 */
487 if (sym && sym->namespace == NS_TYPEDEF) {
488 sparse_error(token->pos, "typename in expression");
489 sym = NULL;
490 }
491 expr->symbol_name = token->ident;
492 expr->symbol = sym;
493
494 /*
495 * A pointer to an lvalue designating a static storage
496 * duration object is an address constant [6.6(9)].
497 */
498 if (sym && (sym->ctype.modifiers & (MOD_TOPLEVEL | MOD_STATIC)))
499 expr->flags = CEF_ADDR;
500
501 token = next;
502 break;
503 }
504
505 case TOKEN_STRING:
506 case TOKEN_WIDE_STRING:
507 expr = alloc_expression(token->pos, EXPR_STRING);
508 token = get_string_constant(token, expr);
509 break;
510
511 case TOKEN_SPECIAL:
512 if (token->special == '(') {
513 expr = alloc_expression(token->pos, EXPR_PREOP);
514 expr->op = '(';
515 token = parens_expression(token, &expr->unop, "in expression");
516 break;
517 }
518 if (token->special == '[' && lookup_type(token->next)) {
519 expr = alloc_expression(token->pos, EXPR_TYPE);
520 token = typename(token->next, &expr->symbol, NULL);
521 token = expect(token, ']', "in type expression");
522 break;
523 }
524
525 default:
526 ;
527 }
528 *tree = expr;
529 return token;
530 }
531
532 static struct token *expression_list(struct token *token, struct expression_list **list)
533 {
534 while (!match_op(token, ')')) {
535 struct expression *expr = NULL;
536 token = assignment_expression(token, &expr);
537 if (!expr)
538 break;
539 add_expression(list, expr);
540 if (!match_op(token, ','))
541 break;
542 token = token->next;
543 }
544 return token;
545 }
546
547 /*
548 * extend to deal with the ambiguous C grammar for parsing
549 * a cast expressions followed by an initializer.
550 */
551 static struct token *postfix_expression(struct token *token, struct expression **tree, struct expression *cast_init_expr)
552 {
553 struct expression *expr = cast_init_expr;
554
555 if (!expr)
556 token = primary_expression(token, &expr);
557
558 while (expr && token_type(token) == TOKEN_SPECIAL) {
559 switch (token->special) {
560 case '[': { /* Array dereference */
561 struct expression *deref = alloc_expression(token->pos, EXPR_PREOP);
562 struct expression *add = alloc_expression(token->pos, EXPR_BINOP);
563
564 deref->op = '*';
565 deref->unop = add;
566
567 add->op = '+';
568 add->left = expr;
569 token = parse_expression(token->next, &add->right);
570 token = expect(token, ']', "at end of array dereference");
571 expr = deref;
572 continue;
573 }
574 case SPECIAL_INCREMENT: /* Post-increment */
575 case SPECIAL_DECREMENT: { /* Post-decrement */
576 struct expression *post = alloc_expression(token->pos, EXPR_POSTOP);
577 post->op = token->special;
578 post->unop = expr;
579 expr = post;
580 token = token->next;
581 continue;
582 }
583 case SPECIAL_DEREFERENCE: { /* Structure pointer member dereference */
584 /* "x->y" is just shorthand for "(*x).y" */
585 struct expression *inner = alloc_expression(token->pos, EXPR_PREOP);
586 inner->op = '*';
587 inner->unop = expr;
588 expr = inner;
589 }
590 /* Fall through!! */
591 case '.': { /* Structure member dereference */
592 struct expression *deref = alloc_expression(token->pos, EXPR_DEREF);
593 deref->op = '.';
594 deref->deref = expr;
595 token = token->next;
596 if (token_type(token) != TOKEN_IDENT) {
597 sparse_error(token->pos, "Expected member name");
598 break;
599 }
600 deref->member = token->ident;
601 deref->member_offset = -1;
602 token = token->next;
603 expr = deref;
604 continue;
605 }
606
607 case '(': { /* Function call */
608 struct expression *call = alloc_expression(token->pos, EXPR_CALL);
609 call->op = '(';
610 call->fn = expr;
611 token = expression_list(token->next, &call->args);
612 token = expect(token, ')', "in function call");
613 expr = call;
614 continue;
615 }
616
617 default:
618 break;
619 }
620 break;
621 }
622 *tree = expr;
623 return token;
624 }
625
626 static struct token *cast_expression(struct token *token, struct expression **tree);
627 static struct token *unary_expression(struct token *token, struct expression **tree);
628
629 static struct token *type_info_expression(struct token *token,
630 struct expression **tree, int type)
631 {
632 struct expression *expr = alloc_expression(token->pos, type);
633 struct token *p;
634
635 *tree = expr;
636 expr->flags = CEF_SET_ICE; /* XXX: VLA support will need that changed */
637 token = token->next;
638 if (!match_op(token, '(') || !lookup_type(token->next))
639 return unary_expression(token, &expr->cast_expression);
640 p = token;
641 token = typename(token->next, &expr->cast_type, NULL);
642
643 if (!match_op(token, ')')) {
644 static const char * error[] = {
645 [EXPR_SIZEOF] = "at end of sizeof",
646 [EXPR_ALIGNOF] = "at end of __alignof__",
647 [EXPR_PTRSIZEOF] = "at end of __sizeof_ptr__"
648 };
649 return expect(token, ')', error[type]);
650 }
651
652 token = token->next;
653 /*
654 * C99 ambiguity: the typename might have been the beginning
655 * of a typed initializer expression..
656 */
657 if (match_op(token, '{')) {
658 struct expression *cast = alloc_expression(p->pos, EXPR_CAST);
659 cast->cast_type = expr->cast_type;
660 expr->cast_type = NULL;
661 expr->cast_expression = cast;
662 token = initializer(&cast->cast_expression, token);
663 token = postfix_expression(token, &expr->cast_expression, cast);
664 }
665 return token;
666 }
667
668 static struct token *unary_expression(struct token *token, struct expression **tree)
669 {
670 if (token_type(token) == TOKEN_IDENT) {
671 struct ident *ident = token->ident;
672 if (ident->reserved) {
673 static const struct {
674 struct ident *id;
675 int type;
676 } type_information[] = {
677 { &sizeof_ident, EXPR_SIZEOF },
678 { &__alignof___ident, EXPR_ALIGNOF },
679 { &__alignof_ident, EXPR_ALIGNOF },
680 { &_Alignof_ident, EXPR_ALIGNOF },
681 { &__sizeof_ptr___ident, EXPR_PTRSIZEOF },
682 };
683 int i;
684 for (i = 0; i < ARRAY_SIZE(type_information); i++) {
685 if (ident == type_information[i].id)
686 return type_info_expression(token, tree, type_information[i].type);
687 }
688 }
689 }
690
691 if (token_type(token) == TOKEN_SPECIAL) {
692 if (match_oplist(token->special,
693 SPECIAL_INCREMENT, SPECIAL_DECREMENT,
694 '&', '*', 0)) {
695 struct expression *unop;
696 struct expression *unary;
697 struct token *next;
698
699 next = cast_expression(token->next, &unop);
700 if (!unop) {
701 sparse_error(token->pos, "Syntax error in unary expression");
702 *tree = NULL;
703 return next;
704 }
705 unary = alloc_expression(token->pos, EXPR_PREOP);
706 unary->op = token->special;
707 unary->unop = unop;
708 *tree = unary;
709 return next;
710 }
711 /* possibly constant ones */
712 if (match_oplist(token->special, '+', '-', '~', '!', 0)) {
713 struct expression *unop;
714 struct expression *unary;
715 struct token *next;
716
717 next = cast_expression(token->next, &unop);
718 if (!unop) {
719 sparse_error(token->pos, "Syntax error in unary expression");
720 *tree = NULL;
721 return next;
722 }
723 unary = alloc_expression(token->pos, EXPR_PREOP);
724 unary->op = token->special;
725 unary->unop = unop;
726 *tree = unary;
727 return next;
728 }
729 /* Gcc extension: &&label gives the address of a label */
730 if (match_op(token, SPECIAL_LOGICAL_AND) &&
731 token_type(token->next) == TOKEN_IDENT) {
732 struct expression *label = alloc_expression(token->pos, EXPR_LABEL);
733 struct symbol *sym = label_symbol(token->next, 1);
734 if (!(sym->ctype.modifiers & MOD_ADDRESSABLE)) {
735 sym->ctype.modifiers |= MOD_ADDRESSABLE;
736 add_symbol(&function_computed_target_list, sym);
737 }
738 check_label_usage(sym, token->pos);
739 label->flags = CEF_ADDR;
740 label->label_symbol = sym;
741 *tree = label;
742 return token->next->next;
743 }
744
745 }
746
747 return postfix_expression(token, tree, NULL);
748 }
749
750 /*
751 * Ambiguity: a '(' can be either a cast-expression or
752 * a primary-expression depending on whether it is followed
753 * by a type or not.
754 *
755 * additional ambiguity: a "cast expression" followed by
756 * an initializer is really a postfix-expression.
757 */
758 static struct token *cast_expression(struct token *token, struct expression **tree)
759 {
760 if (match_op(token, '(')) {
761 struct token *next = token->next;
762 if (lookup_type(next)) {
763 struct expression *cast = alloc_expression(next->pos, EXPR_CAST);
764 struct expression *v;
765 struct symbol *sym;
766 int is_force;
767
768 token = typename(next, &sym, &is_force);
769 cast->cast_type = sym;
770 token = expect(token, ')', "at end of cast operator");
771 if (match_op(token, '{')) {
772 if (toplevel(block_scope))
773 sym->ctype.modifiers |= MOD_TOPLEVEL;
774 if (is_force)
775 warning(sym->pos,
776 "[force] in compound literal");
777 token = initializer(&cast->cast_expression, token);
778 return postfix_expression(token, tree, cast);
779 }
780 *tree = cast;
781 if (is_force)
782 cast->type = EXPR_FORCE_CAST;
783 token = cast_expression(token, &v);
784 if (!v)
785 return token;
786 cast->cast_expression = v;
787 return token;
788 }
789 }
790 return unary_expression(token, tree);
791 }
792
793 /*
794 * Generic left-to-right binop parsing
795 *
796 * This _really_ needs to be inlined, because that makes the inner
797 * function call statically deterministic rather than a totally
798 * unpredictable indirect call. But gcc-3 is so "clever" that it
799 * doesn't do so by default even when you tell it to inline it.
800 *
801 * Making it a macro avoids the inlining problem, and also means
802 * that we can pass in the op-comparison as an expression rather
803 * than create a data structure for it.
804 */
805
806 #define LR_BINOP_EXPRESSION(__token, tree, type, inner, compare) \
807 struct expression *left = NULL; \
808 struct token * next = inner(__token, &left); \
809 \
810 if (left) { \
811 while (token_type(next) == TOKEN_SPECIAL) { \
812 struct expression *top, *right = NULL; \
813 int op = next->special; \
814 \
815 if (!(compare)) \
816 goto out; \
817 top = alloc_expression(next->pos, type); \
818 next = inner(next->next, &right); \
819 if (!right) { \
820 sparse_error(next->pos, "No right hand side of '%s'-expression", show_special(op)); \
821 break; \
822 } \
823 top->op = op; \
824 top->left = left; \
825 top->right = right; \
826 left = top; \
827 } \
828 } \
829 out: \
830 *tree = left; \
831 return next; \
832
833 static struct token *multiplicative_expression(struct token *token, struct expression **tree)
834 {
835 LR_BINOP_EXPRESSION(
836 token, tree, EXPR_BINOP, cast_expression,
837 (op == '*') || (op == '/') || (op == '%')
838 );
839 }
840
841 static struct token *additive_expression(struct token *token, struct expression **tree)
842 {
843 LR_BINOP_EXPRESSION(
844 token, tree, EXPR_BINOP, multiplicative_expression,
845 (op == '+') || (op == '-')
846 );
847 }
848
849 static struct token *shift_expression(struct token *token, struct expression **tree)
850 {
851 LR_BINOP_EXPRESSION(
852 token, tree, EXPR_BINOP, additive_expression,
853 (op == SPECIAL_LEFTSHIFT) || (op == SPECIAL_RIGHTSHIFT)
854 );
855 }
856
857 static struct token *relational_expression(struct token *token, struct expression **tree)
858 {
859 LR_BINOP_EXPRESSION(
860 token, tree, EXPR_COMPARE, shift_expression,
861 (op == '<') || (op == '>') ||
862 (op == SPECIAL_LTE) || (op == SPECIAL_GTE)
863 );
864 }
865
866 static struct token *equality_expression(struct token *token, struct expression **tree)
867 {
868 LR_BINOP_EXPRESSION(
869 token, tree, EXPR_COMPARE, relational_expression,
870 (op == SPECIAL_EQUAL) || (op == SPECIAL_NOTEQUAL)
871 );
872 }
873
874 static struct token *bitwise_and_expression(struct token *token, struct expression **tree)
875 {
876 LR_BINOP_EXPRESSION(
877 token, tree, EXPR_BINOP, equality_expression,
878 (op == '&')
879 );
880 }
881
882 static struct token *bitwise_xor_expression(struct token *token, struct expression **tree)
883 {
884 LR_BINOP_EXPRESSION(
885 token, tree, EXPR_BINOP, bitwise_and_expression,
886 (op == '^')
887 );
888 }
889
890 static struct token *bitwise_or_expression(struct token *token, struct expression **tree)
891 {
892 LR_BINOP_EXPRESSION(
893 token, tree, EXPR_BINOP, bitwise_xor_expression,
894 (op == '|')
895 );
896 }
897
898 static struct token *logical_and_expression(struct token *token, struct expression **tree)
899 {
900 LR_BINOP_EXPRESSION(
901 token, tree, EXPR_LOGICAL, bitwise_or_expression,
902 (op == SPECIAL_LOGICAL_AND)
903 );
904 }
905
906 static struct token *logical_or_expression(struct token *token, struct expression **tree)
907 {
908 LR_BINOP_EXPRESSION(
909 token, tree, EXPR_LOGICAL, logical_and_expression,
910 (op == SPECIAL_LOGICAL_OR)
911 );
912 }
913
914 struct token *conditional_expression(struct token *token, struct expression **tree)
915 {
916 token = logical_or_expression(token, tree);
917 if (*tree && match_op(token, '?')) {
918 struct expression *expr = alloc_expression(token->pos, EXPR_CONDITIONAL);
919 expr->op = token->special;
920 expr->conditional = *tree;
921 *tree = expr;
922 token = parse_expression(token->next, &expr->cond_true);
923 token = expect(token, ':', "in conditional expression");
924 token = conditional_expression(token, &expr->cond_false);
925 }
926 return token;
927 }
928
929 struct token *assignment_expression(struct token *token, struct expression **tree)
930 {
931 token = conditional_expression(token, tree);
932 if (*tree && token_type(token) == TOKEN_SPECIAL) {
933 static const int assignments[] = {
934 '=',
935 SPECIAL_ADD_ASSIGN, SPECIAL_SUB_ASSIGN,
936 SPECIAL_MUL_ASSIGN, SPECIAL_DIV_ASSIGN,
937 SPECIAL_MOD_ASSIGN, SPECIAL_SHL_ASSIGN,
938 SPECIAL_SHR_ASSIGN, SPECIAL_AND_ASSIGN,
939 SPECIAL_OR_ASSIGN, SPECIAL_XOR_ASSIGN };
940 int i, op = token->special;
941 for (i = 0; i < ARRAY_SIZE(assignments); i++)
942 if (assignments[i] == op) {
943 struct expression * expr = alloc_expression(token->pos, EXPR_ASSIGNMENT);
944 struct token *next = token->next;
945 expr->left = *tree;
946 expr->op = op;
947 *tree = expr;
948 token = assignment_expression(next, &expr->right);
949 if (token == next)
950 expression_error(expr, "expression expected before '%s'", show_token(token));
951 return token;
952 }
953 }
954 return token;
955 }
956
957 static struct token *comma_expression(struct token *token, struct expression **tree)
958 {
959 LR_BINOP_EXPRESSION(
960 token, tree, EXPR_COMMA, assignment_expression,
961 (op == ',')
962 );
963 }
964
965 struct token *parse_expression(struct token *token, struct expression **tree)
966 {
967 return comma_expression(token,tree);
968 }
969
970
Static analysis for C