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Remove some false positives and enable the check.
[smatch.git] / evaluate.c
blob2a126ddb5aa58246f7dc9564bd9ccde3fa704ea3
1 /*
2 * sparse/evaluate.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 * Evaluate constant expressions.
10 */
11 #include <stdlib.h>
12 #include <stdarg.h>
13 #include <stddef.h>
14 #include <stdio.h>
15 #include <string.h>
16 #include <ctype.h>
17 #include <unistd.h>
18 #include <fcntl.h>
19 #include <limits.h>
20
21 #include "lib.h"
22 #include "allocate.h"
23 #include "parse.h"
24 #include "token.h"
25 #include "symbol.h"
26 #include "target.h"
27 #include "expression.h"
28
29 struct symbol *current_fn;
30
31 static struct symbol *degenerate(struct expression *expr);
32 static struct symbol *evaluate_symbol(struct symbol *sym);
33
34 static struct symbol *evaluate_symbol_expression(struct expression *expr)
35 {
36 struct expression *addr;
37 struct symbol *sym = expr->symbol;
38 struct symbol *base_type;
39
40 if (!sym) {
41 expression_error(expr, "undefined identifier '%s'", show_ident(expr->symbol_name));
42 return NULL;
43 }
44
45 examine_symbol_type(sym);
46
47 base_type = get_base_type(sym);
48 if (!base_type) {
49 expression_error(expr, "identifier '%s' has no type", show_ident(expr->symbol_name));
50 return NULL;
51 }
52
53 addr = alloc_expression(expr->pos, EXPR_SYMBOL);
54 addr->symbol = sym;
55 addr->symbol_name = expr->symbol_name;
56 addr->ctype = &lazy_ptr_ctype; /* Lazy evaluation: we need to do a proper job if somebody does &sym */
57 expr->type = EXPR_PREOP;
58 expr->op = '*';
59 expr->unop = addr;
60
61 /* The type of a symbol is the symbol itself! */
62 expr->ctype = sym;
63 return sym;
64 }
65
66 static struct symbol *evaluate_string(struct expression *expr)
67 {
68 struct symbol *sym = alloc_symbol(expr->pos, SYM_NODE);
69 struct symbol *array = alloc_symbol(expr->pos, SYM_ARRAY);
70 struct expression *addr = alloc_expression(expr->pos, EXPR_SYMBOL);
71 struct expression *initstr = alloc_expression(expr->pos, EXPR_STRING);
72 unsigned int length = expr->string->length;
73
74 sym->array_size = alloc_const_expression(expr->pos, length);
75 sym->bit_size = bits_in_char * length;
76 sym->ctype.alignment = 1;
77 sym->string = 1;
78 sym->ctype.modifiers = MOD_STATIC;
79 sym->ctype.base_type = array;
80 sym->initializer = initstr;
81
82 initstr->ctype = sym;
83 initstr->string = expr->string;
84
85 array->array_size = sym->array_size;
86 array->bit_size = bits_in_char * length;
87 array->ctype.alignment = 1;
88 array->ctype.modifiers = MOD_STATIC;
89 array->ctype.base_type = &char_ctype;
90
91 addr->symbol = sym;
92 addr->ctype = &lazy_ptr_ctype;
93
94 expr->type = EXPR_PREOP;
95 expr->op = '*';
96 expr->unop = addr;
97 expr->ctype = sym;
98 return sym;
99 }
100
101 /* type has come from classify_type and is an integer type */
102 static inline struct symbol *integer_promotion(struct symbol *type)
103 {
104 struct symbol *orig_type = type;
105 unsigned long mod = type->ctype.modifiers;
106 int width = type->bit_size;
107
108 /*
109 * Bitfields always promote to the base type,
110 * even if the bitfield might be bigger than
111 * an "int".
112 */
113 if (type->type == SYM_BITFIELD) {
114 type = type->ctype.base_type;
115 orig_type = type;
116 }
117 mod = type->ctype.modifiers;
118 if (width < bits_in_int)
119 return &int_ctype;
120
121 /* If char/short has as many bits as int, it still gets "promoted" */
122 if (mod & (MOD_CHAR | MOD_SHORT)) {
123 if (mod & MOD_UNSIGNED)
124 return &uint_ctype;
125 return &int_ctype;
126 }
127 return orig_type;
128 }
129
130 /*
131 * integer part of usual arithmetic conversions:
132 * integer promotions are applied
133 * if left and right are identical, we are done
134 * if signedness is the same, convert one with lower rank
135 * unless unsigned argument has rank lower than signed one, convert the
136 * signed one.
137 * if signed argument is bigger than unsigned one, convert the unsigned.
138 * otherwise, convert signed.
139 *
140 * Leaving aside the integer promotions, that is equivalent to
141 * if identical, don't convert
142 * if left is bigger than right, convert right
143 * if right is bigger than left, convert right
144 * otherwise, if signedness is the same, convert one with lower rank
145 * otherwise convert the signed one.
146 */
147 static struct symbol *bigger_int_type(struct symbol *left, struct symbol *right)
148 {
149 unsigned long lmod, rmod;
150
151 left = integer_promotion(left);
152 right = integer_promotion(right);
153
154 if (left == right)
155 goto left;
156
157 if (left->bit_size > right->bit_size)
158 goto left;
159
160 if (right->bit_size > left->bit_size)
161 goto right;
162
163 lmod = left->ctype.modifiers;
164 rmod = right->ctype.modifiers;
165 if ((lmod ^ rmod) & MOD_UNSIGNED) {
166 if (lmod & MOD_UNSIGNED)
167 goto left;
168 } else if ((lmod & ~rmod) & (MOD_LONG | MOD_LONGLONG))
169 goto left;
170 right:
171 left = right;
172 left:
173 return left;
174 }
175
176 static int same_cast_type(struct symbol *orig, struct symbol *new)
177 {
178 return orig->bit_size == new->bit_size && orig->bit_offset == new->bit_offset;
179 }
180
181 static struct symbol *base_type(struct symbol *node, unsigned long *modp, unsigned long *asp)
182 {
183 unsigned long mod, as;
184
185 mod = 0; as = 0;
186 while (node) {
187 mod |= node->ctype.modifiers;
188 as |= node->ctype.as;
189 if (node->type == SYM_NODE) {
190 node = node->ctype.base_type;
191 continue;
192 }
193 break;
194 }
195 *modp = mod & ~MOD_IGNORE;
196 *asp = as;
197 return node;
198 }
199
200 static int is_same_type(struct expression *expr, struct symbol *new)
201 {
202 struct symbol *old = expr->ctype;
203 unsigned long oldmod, newmod, oldas, newas;
204
205 old = base_type(old, &oldmod, &oldas);
206 new = base_type(new, &newmod, &newas);
207
208 /* Same base type, same address space? */
209 if (old == new && oldas == newas) {
210 unsigned long difmod;
211
212 /* Check the modifier bits. */
213 difmod = (oldmod ^ newmod) & ~MOD_NOCAST;
214
215 /* Exact same type? */
216 if (!difmod)
217 return 1;
218
219 /*
220 * Not the same type, but differs only in "const".
221 * Don't warn about MOD_NOCAST.
222 */
223 if (difmod == MOD_CONST)
224 return 0;
225 }
226 if ((oldmod | newmod) & MOD_NOCAST) {
227 const char *tofrom = "to/from";
228 if (!(newmod & MOD_NOCAST))
229 tofrom = "from";
230 if (!(oldmod & MOD_NOCAST))
231 tofrom = "to";
232 warning(expr->pos, "implicit cast %s nocast type", tofrom);
233 }
234 return 0;
235 }
236
237 static void
238 warn_for_different_enum_types (struct position pos,
239 struct symbol *typea,
240 struct symbol *typeb)
241 {
242 if (!Wenum_mismatch)
243 return;
244 if (typea->type == SYM_NODE)
245 typea = typea->ctype.base_type;
246 if (typeb->type == SYM_NODE)
247 typeb = typeb->ctype.base_type;
248
249 if (typea == typeb)
250 return;
251
252 if (typea->type == SYM_ENUM && typeb->type == SYM_ENUM) {
253 warning(pos, "mixing different enum types");
254 info(pos, " %s versus", show_typename(typea));
255 info(pos, " %s", show_typename(typeb));
256 }
257 }
258
259 /*
260 * This gets called for implicit casts in assignments and
261 * integer promotion. We often want to try to move the
262 * cast down, because the ops involved may have been
263 * implicitly cast up, and we can get rid of the casts
264 * early.
265 */
266 static struct expression * cast_to(struct expression *old, struct symbol *type)
267 {
268 struct expression *expr;
269
270 warn_for_different_enum_types (old->pos, old->ctype, type);
271
272 if (old->ctype != &null_ctype && is_same_type(old, type))
273 return old;
274
275 /*
276 * See if we can simplify the op. Move the cast down.
277 */
278 switch (old->type) {
279 case EXPR_PREOP:
280 if (old->ctype->bit_size < type->bit_size)
281 break;
282 if (old->op == '~') {
283 old->ctype = type;
284 old->unop = cast_to(old->unop, type);
285 return old;
286 }
287 break;
288
289 case EXPR_IMPLIED_CAST:
290 warn_for_different_enum_types(old->pos, old->ctype, type);
291
292 if (old->ctype->bit_size >= type->bit_size) {
293 struct expression *orig = old->cast_expression;
294 if (same_cast_type(orig->ctype, type))
295 return orig;
296 if (old->ctype->bit_offset == type->bit_offset) {
297 old->ctype = type;
298 old->cast_type = type;
299 return old;
300 }
301 }
302 break;
303
304 default:
305 /* nothing */;
306 }
307
308 expr = alloc_expression(old->pos, EXPR_IMPLIED_CAST);
309 expr->flags = old->flags;
310 expr->ctype = type;
311 expr->cast_type = type;
312 expr->cast_expression = old;
313 return expr;
314 }
315
316 static int is_type_type(struct symbol *type)
317 {
318 return (type->ctype.modifiers & MOD_TYPE) != 0;
319 }
320
321 int is_ptr_type(struct symbol *type)
322 {
323 if (type->type == SYM_NODE)
324 type = type->ctype.base_type;
325 return type->type == SYM_PTR || type->type == SYM_ARRAY || type->type == SYM_FN;
326 }
327
328 static inline int is_float_type(struct symbol *type)
329 {
330 if (type->type == SYM_NODE)
331 type = type->ctype.base_type;
332 return type->ctype.base_type == &fp_type;
333 }
334
335 static inline int is_byte_type(struct symbol *type)
336 {
337 return type->bit_size == bits_in_char && type->type != SYM_BITFIELD;
338 }
339
340 enum {
341 TYPE_NUM = 1,
342 TYPE_BITFIELD = 2,
343 TYPE_RESTRICT = 4,
344 TYPE_FLOAT = 8,
345 TYPE_PTR = 16,
346 TYPE_COMPOUND = 32,
347 TYPE_FOULED = 64,
348 TYPE_FN = 128,
349 };
350
351 static inline int classify_type(struct symbol *type, struct symbol **base)
352 {
353 static int type_class[SYM_BAD + 1] = {
354 [SYM_PTR] = TYPE_PTR,
355 [SYM_FN] = TYPE_PTR | TYPE_FN,
356 [SYM_ARRAY] = TYPE_PTR | TYPE_COMPOUND,
357 [SYM_STRUCT] = TYPE_COMPOUND,
358 [SYM_UNION] = TYPE_COMPOUND,
359 [SYM_BITFIELD] = TYPE_NUM | TYPE_BITFIELD,
360 [SYM_RESTRICT] = TYPE_NUM | TYPE_RESTRICT,
361 [SYM_FOULED] = TYPE_NUM | TYPE_RESTRICT | TYPE_FOULED,
362 };
363 if (type->type == SYM_NODE)
364 type = type->ctype.base_type;
365 if (type->type == SYM_ENUM)
366 type = type->ctype.base_type;
367 *base = type;
368 if (type->type == SYM_BASETYPE) {
369 if (type->ctype.base_type == &int_type)
370 return TYPE_NUM;
371 if (type->ctype.base_type == &fp_type)
372 return TYPE_NUM | TYPE_FLOAT;
373 }
374 return type_class[type->type];
375 }
376
377 #define is_int(class) ((class & (TYPE_NUM | TYPE_FLOAT)) == TYPE_NUM)
378
379 static inline int is_string_type(struct symbol *type)
380 {
381 if (type->type == SYM_NODE)
382 type = type->ctype.base_type;
383 return type->type == SYM_ARRAY && is_byte_type(type->ctype.base_type);
384 }
385
386 static struct symbol *bad_expr_type(struct expression *expr)
387 {
388 sparse_error(expr->pos, "incompatible types for operation (%s)", show_special(expr->op));
389 switch (expr->type) {
390 case EXPR_BINOP:
391 case EXPR_COMPARE:
392 info(expr->pos, " left side has type %s", show_typename(expr->left->ctype));
393 info(expr->pos, " right side has type %s", show_typename(expr->right->ctype));
394 break;
395 case EXPR_PREOP:
396 case EXPR_POSTOP:
397 info(expr->pos, " argument has type %s", show_typename(expr->unop->ctype));
398 break;
399 default:
400 break;
401 }
402
403 expr->flags = 0;
404 return expr->ctype = &bad_ctype;
405 }
406
407 static int restricted_value(struct expression *v, struct symbol *type)
408 {
409 if (v->type != EXPR_VALUE)
410 return 1;
411 if (v->value != 0)
412 return 1;
413 return 0;
414 }
415
416 static int restricted_binop(int op, struct symbol *type)
417 {
418 switch (op) {
419 case '&':
420 case '=':
421 case SPECIAL_AND_ASSIGN:
422 case SPECIAL_OR_ASSIGN:
423 case SPECIAL_XOR_ASSIGN:
424 return 1; /* unfoul */
425 case '|':
426 case '^':
427 case '?':
428 return 2; /* keep fouled */
429 case SPECIAL_EQUAL:
430 case SPECIAL_NOTEQUAL:
431 return 3; /* warn if fouled */
432 default:
433 return 0; /* warn */
434 }
435 }
436
437 static int restricted_unop(int op, struct symbol **type)
438 {
439 if (op == '~') {
440 if ((*type)->bit_size < bits_in_int)
441 *type = befoul(*type);
442 return 0;
443 } if (op == '+')
444 return 0;
445 return 1;
446 }
447
448 /* type should be SYM_FOULED */
449 static inline struct symbol *unfoul(struct symbol *type)
450 {
451 return type->ctype.base_type;
452 }
453
454 static struct symbol *restricted_binop_type(int op,
455 struct expression *left,
456 struct expression *right,
457 int lclass, int rclass,
458 struct symbol *ltype,
459 struct symbol *rtype)
460 {
461 struct symbol *ctype = NULL;
462 if (lclass & TYPE_RESTRICT) {
463 if (rclass & TYPE_RESTRICT) {
464 if (ltype == rtype) {
465 ctype = ltype;
466 } else if (lclass & TYPE_FOULED) {
467 if (unfoul(ltype) == rtype)
468 ctype = ltype;
469 } else if (rclass & TYPE_FOULED) {
470 if (unfoul(rtype) == ltype)
471 ctype = rtype;
472 }
473 } else {
474 if (!restricted_value(right, ltype))
475 ctype = ltype;
476 }
477 } else if (!restricted_value(left, rtype))
478 ctype = rtype;
479
480 if (ctype) {
481 switch (restricted_binop(op, ctype)) {
482 case 1:
483 if ((lclass ^ rclass) & TYPE_FOULED)
484 ctype = unfoul(ctype);
485 break;
486 case 3:
487 if (!(lclass & rclass & TYPE_FOULED))
488 break;
489 case 0:
490 ctype = NULL;
491 default:
492 break;
493 }
494 }
495
496 return ctype;
497 }
498
499 static inline void unrestrict(struct expression *expr,
500 int class, struct symbol **ctype)
501 {
502 if (class & TYPE_RESTRICT) {
503 if (class & TYPE_FOULED)
504 *ctype = unfoul(*ctype);
505 warning(expr->pos, "%s degrades to integer",
506 show_typename(*ctype));
507 *ctype = (*ctype)->ctype.base_type; /* get to arithmetic type */
508 }
509 }
510
511 static struct symbol *usual_conversions(int op,
512 struct expression *left,
513 struct expression *right,
514 int lclass, int rclass,
515 struct symbol *ltype,
516 struct symbol *rtype)
517 {
518 struct symbol *ctype;
519
520 warn_for_different_enum_types(right->pos, left->ctype, right->ctype);
521
522 if ((lclass | rclass) & TYPE_RESTRICT)
523 goto Restr;
524
525 Normal:
526 if (!(lclass & TYPE_FLOAT)) {
527 if (!(rclass & TYPE_FLOAT))
528 return bigger_int_type(ltype, rtype);
529 else
530 return rtype;
531 } else if (rclass & TYPE_FLOAT) {
532 unsigned long lmod = ltype->ctype.modifiers;
533 unsigned long rmod = rtype->ctype.modifiers;
534 if (rmod & ~lmod & (MOD_LONG | MOD_LONGLONG))
535 return rtype;
536 else
537 return ltype;
538 } else
539 return ltype;
540
541 Restr:
542 ctype = restricted_binop_type(op, left, right,
543 lclass, rclass, ltype, rtype);
544 if (ctype)
545 return ctype;
546
547 unrestrict(left, lclass, &ltype);
548 unrestrict(right, rclass, &rtype);
549
550 goto Normal;
551 }
552
553 static inline int lvalue_expression(struct expression *expr)
554 {
555 return expr->type == EXPR_PREOP && expr->op == '*';
556 }
557
558 static inline int is_function(struct symbol *type)
559 {
560 return type && type->type == SYM_FN;
561 }
562
563 static struct symbol *evaluate_ptr_add(struct expression *expr, struct symbol *itype)
564 {
565 struct expression *index = expr->right;
566 struct symbol *ctype, *base;
567 int multiply;
568
569 classify_type(degenerate(expr->left), &ctype);
570 base = examine_pointer_target(ctype);
571
572 if (!base) {
573 expression_error(expr, "missing type information");
574 return NULL;
575 }
576 if (is_function(base)) {
577 expression_error(expr, "arithmetics on pointers to functions");
578 return NULL;
579 }
580
581 /* Get the size of whatever the pointer points to */
582 multiply = base->bit_size >> 3;
583
584 if (ctype == &null_ctype)
585 ctype = &ptr_ctype;
586 expr->ctype = ctype;
587
588 if (multiply == 1 && itype->bit_size >= bits_in_pointer)
589 return ctype;
590
591 if (index->type == EXPR_VALUE) {
592 struct expression *val = alloc_expression(expr->pos, EXPR_VALUE);
593 unsigned long long v = index->value, mask;
594 mask = 1ULL << (itype->bit_size - 1);
595 if (v & mask)
596 v |= -mask;
597 else
598 v &= mask - 1;
599 v *= multiply;
600 mask = 1ULL << (bits_in_pointer - 1);
601 v &= mask | (mask - 1);
602 val->value = v;
603 val->ctype = ssize_t_ctype;
604 expr->right = val;
605 return ctype;
606 }
607
608 if (itype->bit_size < bits_in_pointer)
609 index = cast_to(index, ssize_t_ctype);
610
611 if (multiply > 1) {
612 struct expression *val = alloc_expression(expr->pos, EXPR_VALUE);
613 struct expression *mul = alloc_expression(expr->pos, EXPR_BINOP);
614
615 val->ctype = ssize_t_ctype;
616 val->value = multiply;
617
618 mul->op = '*';
619 mul->ctype = ssize_t_ctype;
620 mul->left = index;
621 mul->right = val;
622 index = mul;
623 }
624
625 expr->right = index;
626 return ctype;
627 }
628
629 static void examine_fn_arguments(struct symbol *fn);
630
631 #define MOD_IGN (MOD_VOLATILE | MOD_CONST)
632
633 const char *type_difference(struct ctype *c1, struct ctype *c2,
634 unsigned long mod1, unsigned long mod2)
635 {
636 unsigned long as1 = c1->as, as2 = c2->as;
637 struct symbol *t1 = c1->base_type;
638 struct symbol *t2 = c2->base_type;
639 int move1 = 1, move2 = 1;
640 mod1 |= c1->modifiers;
641 mod2 |= c2->modifiers;
642 for (;;) {
643 unsigned long diff;
644 int type;
645 struct symbol *base1 = t1->ctype.base_type;
646 struct symbol *base2 = t2->ctype.base_type;
647
648 /*
649 * FIXME! Collect alignment and context too here!
650 */
651 if (move1) {
652 if (t1 && t1->type != SYM_PTR) {
653 mod1 |= t1->ctype.modifiers;
654 as1 |= t1->ctype.as;
655 }
656 move1 = 0;
657 }
658
659 if (move2) {
660 if (t2 && t2->type != SYM_PTR) {
661 mod2 |= t2->ctype.modifiers;
662 as2 |= t2->ctype.as;
663 }
664 move2 = 0;
665 }
666
667 if (t1 == t2)
668 break;
669 if (!t1 || !t2)
670 return "different types";
671
672 if (t1->type == SYM_NODE || t1->type == SYM_ENUM) {
673 t1 = base1;
674 move1 = 1;
675 if (!t1)
676 return "bad types";
677 continue;
678 }
679
680 if (t2->type == SYM_NODE || t2->type == SYM_ENUM) {
681 t2 = base2;
682 move2 = 1;
683 if (!t2)
684 return "bad types";
685 continue;
686 }
687
688 move1 = move2 = 1;
689 type = t1->type;
690 if (type != t2->type)
691 return "different base types";
692
693 switch (type) {
694 default:
695 sparse_error(t1->pos,
696 "internal error: bad type in derived(%d)",
697 type);
698 return "bad types";
699 case SYM_RESTRICT:
700 return "different base types";
701 case SYM_UNION:
702 case SYM_STRUCT:
703 /* allow definition of incomplete structs and unions */
704 if (t1->ident == t2->ident)
705 return NULL;
706 return "different base types";
707 case SYM_ARRAY:
708 /* XXX: we ought to compare sizes */
709 break;
710 case SYM_PTR:
711 if (Waddress_space && as1 != as2)
712 return "different address spaces";
713 /* MOD_SPECIFIER is due to idiocy in parse.c */
714 if ((mod1 ^ mod2) & ~MOD_IGNORE & ~MOD_SPECIFIER)
715 return "different modifiers";
716 /* we could be lazier here */
717 base1 = examine_pointer_target(t1);
718 base2 = examine_pointer_target(t2);
719 mod1 = t1->ctype.modifiers;
720 as1 = t1->ctype.as;
721 mod2 = t2->ctype.modifiers;
722 as2 = t2->ctype.as;
723 break;
724 case SYM_FN: {
725 struct symbol *arg1, *arg2;
726 int i;
727
728 if (Waddress_space && as1 != as2)
729 return "different address spaces";
730 if ((mod1 ^ mod2) & ~MOD_IGNORE & ~MOD_SIGNEDNESS)
731 return "different modifiers";
732 mod1 = t1->ctype.modifiers;
733 as1 = t1->ctype.as;
734 mod2 = t2->ctype.modifiers;
735 as2 = t2->ctype.as;
736
737 if (base1->variadic != base2->variadic)
738 return "incompatible variadic arguments";
739 examine_fn_arguments(t1);
740 examine_fn_arguments(t2);
741 PREPARE_PTR_LIST(t1->arguments, arg1);
742 PREPARE_PTR_LIST(t2->arguments, arg2);
743 i = 1;
744 for (;;) {
745 const char *diffstr;
746 if (!arg1 && !arg2)
747 break;
748 if (!arg1 || !arg2)
749 return "different argument counts";
750 diffstr = type_difference(&arg1->ctype,
751 &arg2->ctype,
752 MOD_IGN, MOD_IGN);
753 if (diffstr) {
754 static char argdiff[80];
755 sprintf(argdiff, "incompatible argument %d (%s)", i, diffstr);
756 return argdiff;
757 }
758 NEXT_PTR_LIST(arg1);
759 NEXT_PTR_LIST(arg2);
760 i++;
761 }
762 FINISH_PTR_LIST(arg2);
763 FINISH_PTR_LIST(arg1);
764 break;
765 }
766 case SYM_BASETYPE:
767 if (Waddress_space && as1 != as2)
768 return "different address spaces";
769 if (base1 != base2)
770 return "different base types";
771 diff = (mod1 ^ mod2) & ~MOD_IGNORE;
772 if (!diff)
773 return NULL;
774 if (diff & MOD_SIZE)
775 return "different type sizes";
776 else if (diff & ~MOD_SIGNEDNESS)
777 return "different modifiers";
778 else
779 return "different signedness";
780 }
781 t1 = base1;
782 t2 = base2;
783 }
784 if (Waddress_space && as1 != as2)
785 return "different address spaces";
786 if ((mod1 ^ mod2) & ~MOD_IGNORE & ~MOD_SIGNEDNESS)
787 return "different modifiers";
788 return NULL;
789 }
790
791 static void bad_null(struct expression *expr)
792 {
793 if (Wnon_pointer_null)
794 warning(expr->pos, "Using plain integer as NULL pointer");
795 }
796
797 static unsigned long target_qualifiers(struct symbol *type)
798 {
799 unsigned long mod = type->ctype.modifiers & MOD_IGN;
800 if (type->ctype.base_type && type->ctype.base_type->type == SYM_ARRAY)
801 mod = 0;
802 return mod;
803 }
804
805 static struct symbol *evaluate_ptr_sub(struct expression *expr)
806 {
807 const char *typediff;
808 struct symbol *ltype, *rtype;
809 struct expression *l = expr->left;
810 struct expression *r = expr->right;
811 struct symbol *lbase, *rbase;
812
813 classify_type(degenerate(l), &ltype);
814 classify_type(degenerate(r), &rtype);
815
816 lbase = examine_pointer_target(ltype);
817 rbase = examine_pointer_target(rtype);
818 typediff = type_difference(&ltype->ctype, &rtype->ctype,
819 target_qualifiers(rtype),
820 target_qualifiers(ltype));
821 if (typediff)
822 expression_error(expr, "subtraction of different types can't work (%s)", typediff);
823
824 if (is_function(lbase)) {
825 expression_error(expr, "subtraction of functions? Share your drugs");
826 return NULL;
827 }
828
829 expr->ctype = ssize_t_ctype;
830 if (lbase->bit_size > bits_in_char) {
831 struct expression *sub = alloc_expression(expr->pos, EXPR_BINOP);
832 struct expression *div = expr;
833 struct expression *val = alloc_expression(expr->pos, EXPR_VALUE);
834 unsigned long value = lbase->bit_size >> 3;
835
836 val->ctype = size_t_ctype;
837 val->value = value;
838
839 if (value & (value-1)) {
840 if (Wptr_subtraction_blows)
841 warning(expr->pos, "potentially expensive pointer subtraction");
842 }
843
844 sub->op = '-';
845 sub->ctype = ssize_t_ctype;
846 sub->left = l;
847 sub->right = r;
848
849 div->op = '/';
850 div->left = sub;
851 div->right = val;
852 }
853
854 return ssize_t_ctype;
855 }
856
857 #define is_safe_type(type) ((type)->ctype.modifiers & MOD_SAFE)
858
859 static struct symbol *evaluate_conditional(struct expression *expr, int iterator)
860 {
861 struct symbol *ctype;
862
863 if (!expr)
864 return NULL;
865
866 if (!iterator && expr->type == EXPR_ASSIGNMENT && expr->op == '=')
867 warning(expr->pos, "assignment expression in conditional");
868
869 ctype = evaluate_expression(expr);
870 if (ctype) {
871 if (is_safe_type(ctype))
872 warning(expr->pos, "testing a 'safe expression'");
873 }
874
875 return ctype;
876 }
877
878 static struct symbol *evaluate_logical(struct expression *expr)
879 {
880 if (!evaluate_conditional(expr->left, 0))
881 return NULL;
882 if (!evaluate_conditional(expr->right, 0))
883 return NULL;
884
885 expr->ctype = &bool_ctype;
886 if (expr->flags) {
887 if (!(expr->left->flags & expr->right->flags & Int_const_expr))
888 expr->flags = 0;
889 }
890 return &bool_ctype;
891 }
892
893 static struct symbol *evaluate_binop(struct expression *expr)
894 {
895 struct symbol *ltype, *rtype, *ctype;
896 int lclass = classify_type(expr->left->ctype, &ltype);
897 int rclass = classify_type(expr->right->ctype, &rtype);
898 int op = expr->op;
899
900 if (expr->flags) {
901 if (!(expr->left->flags & expr->right->flags & Int_const_expr))
902 expr->flags = 0;
903 }
904
905 /* number op number */
906 if (lclass & rclass & TYPE_NUM) {
907 if ((lclass | rclass) & TYPE_FLOAT) {
908 switch (op) {
909 case '+': case '-': case '*': case '/':
910 break;
911 default:
912 return bad_expr_type(expr);
913 }
914 }
915
916 if (op == SPECIAL_LEFTSHIFT || op == SPECIAL_RIGHTSHIFT) {
917 // shifts do integer promotions, but that's it.
918 unrestrict(expr->left, lclass, &ltype);
919 unrestrict(expr->right, rclass, &rtype);
920 ctype = ltype = integer_promotion(ltype);
921 rtype = integer_promotion(rtype);
922 } else {
923 // The rest do usual conversions
924 if (op == '&' && expr->left->type == EXPR_PREOP &&
925 expr->left->op == '!')
926 warning(expr->pos, "dubious: !x & y");
927 ltype = usual_conversions(op, expr->left, expr->right,
928 lclass, rclass, ltype, rtype);
929 ctype = rtype = ltype;
930 }
931
932 expr->left = cast_to(expr->left, ltype);
933 expr->right = cast_to(expr->right, rtype);
934 expr->ctype = ctype;
935 return ctype;
936 }
937
938 /* pointer (+|-) integer */
939 if (lclass & TYPE_PTR && is_int(rclass) && (op == '+' || op == '-')) {
940 unrestrict(expr->right, rclass, &rtype);
941 return evaluate_ptr_add(expr, rtype);
942 }
943
944 /* integer + pointer */
945 if (rclass & TYPE_PTR && is_int(lclass) && op == '+') {
946 struct expression *index = expr->left;
947 unrestrict(index, lclass, &ltype);
948 expr->left = expr->right;
949 expr->right = index;
950 return evaluate_ptr_add(expr, ltype);
951 }
952
953 /* pointer - pointer */
954 if (lclass & rclass & TYPE_PTR && expr->op == '-')
955 return evaluate_ptr_sub(expr);
956
957 return bad_expr_type(expr);
958 }
959
960 static struct symbol *evaluate_comma(struct expression *expr)
961 {
962 expr->ctype = degenerate(expr->right);
963 if (expr->ctype == &null_ctype)
964 expr->ctype = &ptr_ctype;
965 expr->flags &= expr->left->flags & expr->right->flags;
966 return expr->ctype;
967 }
968
969 static int modify_for_unsigned(int op)
970 {
971 if (op == '<')
972 op = SPECIAL_UNSIGNED_LT;
973 else if (op == '>')
974 op = SPECIAL_UNSIGNED_GT;
975 else if (op == SPECIAL_LTE)
976 op = SPECIAL_UNSIGNED_LTE;
977 else if (op == SPECIAL_GTE)
978 op = SPECIAL_UNSIGNED_GTE;
979 return op;
980 }
981
982 static inline int is_null_pointer_constant(struct expression *e)
983 {
984 if (e->ctype == &null_ctype)
985 return 1;
986 if (!(e->flags & Int_const_expr))
987 return 0;
988 return is_zero_constant(e) ? 2 : 0;
989 }
990
991 static struct symbol *evaluate_compare(struct expression *expr)
992 {
993 struct expression *left = expr->left, *right = expr->right;
994 struct symbol *ltype, *rtype, *lbase, *rbase;
995 int lclass = classify_type(degenerate(left), &ltype);
996 int rclass = classify_type(degenerate(right), &rtype);
997 struct symbol *ctype;
998 const char *typediff;
999
1000 if (expr->flags) {
1001 if (!(expr->left->flags & expr->right->flags & Int_const_expr))
1002 expr->flags = 0;
1003 }
1004
1005 /* Type types? */
1006 if (is_type_type(ltype) && is_type_type(rtype))
1007 goto OK;
1008
1009 if (is_safe_type(left->ctype) || is_safe_type(right->ctype))
1010 warning(expr->pos, "testing a 'safe expression'");
1011
1012 /* number on number */
1013 if (lclass & rclass & TYPE_NUM) {
1014 ctype = usual_conversions(expr->op, expr->left, expr->right,
1015 lclass, rclass, ltype, rtype);
1016 expr->left = cast_to(expr->left, ctype);
1017 expr->right = cast_to(expr->right, ctype);
1018 if (ctype->ctype.modifiers & MOD_UNSIGNED)
1019 expr->op = modify_for_unsigned(expr->op);
1020 goto OK;
1021 }
1022
1023 /* at least one must be a pointer */
1024 if (!((lclass | rclass) & TYPE_PTR))
1025 return bad_expr_type(expr);
1026
1027 /* equality comparisons can be with null pointer constants */
1028 if (expr->op == SPECIAL_EQUAL || expr->op == SPECIAL_NOTEQUAL) {
1029 int is_null1 = is_null_pointer_constant(left);
1030 int is_null2 = is_null_pointer_constant(right);
1031 if (is_null1 == 2)
1032 bad_null(left);
1033 if (is_null2 == 2)
1034 bad_null(right);
1035 if (is_null1 && is_null2) {
1036 int positive = expr->op == SPECIAL_EQUAL;
1037 expr->type = EXPR_VALUE;
1038 expr->value = positive;
1039 goto OK;
1040 }
1041 if (is_null1 && (rclass & TYPE_PTR)) {
1042 left = cast_to(left, rtype);
1043 goto OK;
1044 }
1045 if (is_null2 && (lclass & TYPE_PTR)) {
1046 right = cast_to(right, ltype);
1047 goto OK;
1048 }
1049 }
1050 /* both should be pointers */
1051 if (!(lclass & rclass & TYPE_PTR))
1052 return bad_expr_type(expr);
1053 expr->op = modify_for_unsigned(expr->op);
1054
1055 lbase = examine_pointer_target(ltype);
1056 rbase = examine_pointer_target(rtype);
1057
1058 /* they also have special treatment for pointers to void */
1059 if (expr->op == SPECIAL_EQUAL || expr->op == SPECIAL_NOTEQUAL) {
1060 if (ltype->ctype.as == rtype->ctype.as) {
1061 if (lbase == &void_ctype) {
1062 right = cast_to(right, ltype);
1063 goto OK;
1064 }
1065 if (rbase == &void_ctype) {
1066 left = cast_to(left, rtype);
1067 goto OK;
1068 }
1069 }
1070 }
1071
1072 typediff = type_difference(&ltype->ctype, &rtype->ctype,
1073 target_qualifiers(rtype),
1074 target_qualifiers(ltype));
1075 if (!typediff)
1076 goto OK;
1077
1078 expression_error(expr, "incompatible types in comparison expression (%s)", typediff);
1079 return NULL;
1080
1081 OK:
1082 expr->ctype = &bool_ctype;
1083 return &bool_ctype;
1084 }
1085
1086 /*
1087 * NOTE! The degenerate case of "x ? : y", where we don't
1088 * have a true case, this will possibly promote "x" to the
1089 * same type as "y", and thus _change_ the conditional
1090 * test in the expression. But since promotion is "safe"
1091 * for testing, that's OK.
1092 */
1093 static struct symbol *evaluate_conditional_expression(struct expression *expr)
1094 {
1095 struct expression **true;
1096 struct symbol *ctype, *ltype, *rtype, *lbase, *rbase;
1097 int lclass, rclass;
1098 const char * typediff;
1099 int qual;
1100
1101 if (!evaluate_conditional(expr->conditional, 0))
1102 return NULL;
1103 if (!evaluate_expression(expr->cond_false))
1104 return NULL;
1105
1106 ctype = degenerate(expr->conditional);
1107 rtype = degenerate(expr->cond_false);
1108
1109 true = &expr->conditional;
1110 ltype = ctype;
1111 if (expr->cond_true) {
1112 if (!evaluate_expression(expr->cond_true))
1113 return NULL;
1114 ltype = degenerate(expr->cond_true);
1115 true = &expr->cond_true;
1116 }
1117
1118 if (expr->flags) {
1119 int flags = expr->conditional->flags & Int_const_expr;
1120 flags &= (*true)->flags & expr->cond_false->flags;
1121 if (!flags)
1122 expr->flags = 0;
1123 }
1124
1125 lclass = classify_type(ltype, &ltype);
1126 rclass = classify_type(rtype, &rtype);
1127 if (lclass & rclass & TYPE_NUM) {
1128 ctype = usual_conversions('?', *true, expr->cond_false,
1129 lclass, rclass, ltype, rtype);
1130 *true = cast_to(*true, ctype);
1131 expr->cond_false = cast_to(expr->cond_false, ctype);
1132 goto out;
1133 }
1134
1135 if ((lclass | rclass) & TYPE_PTR) {
1136 int is_null1 = is_null_pointer_constant(*true);
1137 int is_null2 = is_null_pointer_constant(expr->cond_false);
1138
1139 if (is_null1 && is_null2) {
1140 *true = cast_to(*true, &ptr_ctype);
1141 expr->cond_false = cast_to(expr->cond_false, &ptr_ctype);
1142 ctype = &ptr_ctype;
1143 goto out;
1144 }
1145 if (is_null1 && (rclass & TYPE_PTR)) {
1146 if (is_null1 == 2)
1147 bad_null(*true);
1148 *true = cast_to(*true, rtype);
1149 ctype = rtype;
1150 goto out;
1151 }
1152 if (is_null2 && (lclass & TYPE_PTR)) {
1153 if (is_null2 == 2)
1154 bad_null(expr->cond_false);
1155 expr->cond_false = cast_to(expr->cond_false, ltype);
1156 ctype = ltype;
1157 goto out;
1158 }
1159 if (!(lclass & rclass & TYPE_PTR)) {
1160 typediff = "different types";
1161 goto Err;
1162 }
1163 /* OK, it's pointer on pointer */
1164 if (ltype->ctype.as != rtype->ctype.as) {
1165 typediff = "different address spaces";
1166 goto Err;
1167 }
1168
1169 /* need to be lazier here */
1170 lbase = examine_pointer_target(ltype);
1171 rbase = examine_pointer_target(rtype);
1172 qual = target_qualifiers(ltype) | target_qualifiers(rtype);
1173
1174 if (lbase == &void_ctype) {
1175 /* XXX: pointers to function should warn here */
1176 ctype = ltype;
1177 goto Qual;
1178
1179 }
1180 if (rbase == &void_ctype) {
1181 /* XXX: pointers to function should warn here */
1182 ctype = rtype;
1183 goto Qual;
1184 }
1185 /* XXX: that should be pointer to composite */
1186 ctype = ltype;
1187 typediff = type_difference(&ltype->ctype, &rtype->ctype,
1188 qual, qual);
1189 if (!typediff)
1190 goto Qual;
1191 goto Err;
1192 }
1193
1194 /* void on void, struct on same struct, union on same union */
1195 if (ltype == rtype) {
1196 ctype = ltype;
1197 goto out;
1198 }
1199 typediff = "different base types";
1200
1201 Err:
1202 expression_error(expr, "incompatible types in conditional expression (%s)", typediff);
1203 return NULL;
1204
1205 out:
1206 expr->ctype = ctype;
1207 return ctype;
1208
1209 Qual:
1210 if (qual & ~ctype->ctype.modifiers) {
1211 struct symbol *sym = alloc_symbol(ctype->pos, SYM_PTR);
1212 *sym = *ctype;
1213 sym->ctype.modifiers |= qual;
1214 ctype = sym;
1215 }
1216 *true = cast_to(*true, ctype);
1217 expr->cond_false = cast_to(expr->cond_false, ctype);
1218 goto out;
1219 }
1220
1221 /* FP assignments can not do modulo or bit operations */
1222 static int compatible_float_op(int op)
1223 {
1224 return op == SPECIAL_ADD_ASSIGN ||
1225 op == SPECIAL_SUB_ASSIGN ||
1226 op == SPECIAL_MUL_ASSIGN ||
1227 op == SPECIAL_DIV_ASSIGN;
1228 }
1229
1230 static int evaluate_assign_op(struct expression *expr)
1231 {
1232 struct symbol *target = expr->left->ctype;
1233 struct symbol *source = expr->right->ctype;
1234 struct symbol *t, *s;
1235 int tclass = classify_type(target, &t);
1236 int sclass = classify_type(source, &s);
1237 int op = expr->op;
1238
1239 if (tclass & sclass & TYPE_NUM) {
1240 if (tclass & TYPE_FLOAT && !compatible_float_op(op)) {
1241 expression_error(expr, "invalid assignment");
1242 return 0;
1243 }
1244 if (tclass & TYPE_RESTRICT) {
1245 if (!restricted_binop(op, t)) {
1246 warning(expr->pos, "bad assignment (%s) to %s",
1247 show_special(op), show_typename(t));
1248 expr->right = cast_to(expr->right, target);
1249 return 0;
1250 }
1251 /* allowed assignments unfoul */
1252 if (sclass & TYPE_FOULED && unfoul(s) == t)
1253 goto Cast;
1254 if (!restricted_value(expr->right, t))
1255 return 1;
1256 } else if (!(sclass & TYPE_RESTRICT))
1257 goto Cast;
1258 /* source and target would better be identical restricted */
1259 if (t == s)
1260 return 1;
1261 warning(expr->pos, "invalid assignment: %s", show_special(op));
1262 info(expr->pos, " left side has type %s", show_typename(t));
1263 info(expr->pos, " right side has type %s", show_typename(s));
1264 expr->right = cast_to(expr->right, target);
1265 return 0;
1266 }
1267 if (tclass == TYPE_PTR && is_int(sclass)) {
1268 if (op == SPECIAL_ADD_ASSIGN || op == SPECIAL_SUB_ASSIGN) {
1269 unrestrict(expr->right, sclass, &s);
1270 evaluate_ptr_add(expr, s);
1271 return 1;
1272 }
1273 expression_error(expr, "invalid pointer assignment");
1274 return 0;
1275 }
1276
1277 expression_error(expr, "invalid assignment");
1278 return 0;
1279
1280 Cast:
1281 expr->right = cast_to(expr->right, target);
1282 return 1;
1283 }
1284
1285 static int whitelist_pointers(struct symbol *t1, struct symbol *t2)
1286 {
1287 if (t1 == t2)
1288 return 0; /* yes, 0 - we don't want a cast_to here */
1289 if (t1 == &void_ctype)
1290 return 1;
1291 if (t2 == &void_ctype)
1292 return 1;
1293 if (classify_type(t1, &t1) != TYPE_NUM)
1294 return 0;
1295 if (classify_type(t2, &t2) != TYPE_NUM)
1296 return 0;
1297 if (t1 == t2)
1298 return 1;
1299 if (t1->ctype.modifiers & t2->ctype.modifiers & MOD_CHAR)
1300 return 1;
1301 if ((t1->ctype.modifiers ^ t2->ctype.modifiers) & MOD_SIZE)
1302 return 0;
1303 return !Wtypesign;
1304 }
1305
1306 static int compatible_assignment_types(struct expression *expr, struct symbol *target,
1307 struct expression **rp, const char *where)
1308 {
1309 const char *typediff;
1310 struct symbol *source = degenerate(*rp);
1311 struct symbol *t, *s;
1312 int tclass = classify_type(target, &t);
1313 int sclass = classify_type(source, &s);
1314
1315 if (tclass & sclass & TYPE_NUM) {
1316 if (tclass & TYPE_RESTRICT) {
1317 /* allowed assignments unfoul */
1318 if (sclass & TYPE_FOULED && unfoul(s) == t)
1319 goto Cast;
1320 if (!restricted_value(*rp, target))
1321 return 1;
1322 if (s == t)
1323 return 1;
1324 } else if (!(sclass & TYPE_RESTRICT))
1325 goto Cast;
1326 typediff = "different base types";
1327 goto Err;
1328 }
1329
1330 if (tclass == TYPE_PTR) {
1331 unsigned long mod1, mod2;
1332 struct symbol *b1, *b2;
1333 // NULL pointer is always OK
1334 int is_null = is_null_pointer_constant(*rp);
1335 if (is_null) {
1336 if (is_null == 2)
1337 bad_null(*rp);
1338 goto Cast;
1339 }
1340 if (!(sclass & TYPE_PTR)) {
1341 typediff = "different base types";
1342 goto Err;
1343 }
1344 b1 = examine_pointer_target(t);
1345 b2 = examine_pointer_target(s);
1346 mod1 = target_qualifiers(t);
1347 mod2 = target_qualifiers(s);
1348 if (whitelist_pointers(b1, b2)) {
1349 /*
1350 * assignments to/from void * are OK, provided that
1351 * we do not remove qualifiers from pointed to [C]
1352 * or mix address spaces [sparse].
1353 */
1354 if (t->ctype.as != s->ctype.as) {
1355 typediff = "different address spaces";
1356 goto Err;
1357 }
1358 if (mod2 & ~mod1) {
1359 typediff = "different modifiers";
1360 goto Err;
1361 }
1362 goto Cast;
1363 }
1364 /* It's OK if the target is more volatile or const than the source */
1365 typediff = type_difference(&t->ctype, &s->ctype, 0, mod1);
1366 if (typediff)
1367 goto Err;
1368 return 1;
1369 }
1370
1371 if ((tclass & TYPE_COMPOUND) && s == t)
1372 return 1;
1373
1374 if (tclass & TYPE_NUM) {
1375 /* XXX: need to turn into comparison with NULL */
1376 if (t == &bool_ctype && (sclass & TYPE_PTR))
1377 goto Cast;
1378 typediff = "different base types";
1379 goto Err;
1380 }
1381 typediff = "invalid types";
1382
1383 Err:
1384 warning(expr->pos, "incorrect type in %s (%s)", where, typediff);
1385 info(expr->pos, " expected %s", show_typename(target));
1386 info(expr->pos, " got %s", show_typename(source));
1387 *rp = cast_to(*rp, target);
1388 return 0;
1389 Cast:
1390 *rp = cast_to(*rp, target);
1391 return 1;
1392 }
1393
1394 static void mark_assigned(struct expression *expr)
1395 {
1396 struct symbol *sym;
1397
1398 if (!expr)
1399 return;
1400 switch (expr->type) {
1401 case EXPR_SYMBOL:
1402 sym = expr->symbol;
1403 if (!sym)
1404 return;
1405 if (sym->type != SYM_NODE)
1406 return;
1407 sym->ctype.modifiers |= MOD_ASSIGNED;
1408 return;
1409
1410 case EXPR_BINOP:
1411 mark_assigned(expr->left);
1412 mark_assigned(expr->right);
1413 return;
1414 case EXPR_CAST:
1415 case EXPR_FORCE_CAST:
1416 mark_assigned(expr->cast_expression);
1417 return;
1418 case EXPR_SLICE:
1419 mark_assigned(expr->base);
1420 return;
1421 default:
1422 /* Hmm? */
1423 return;
1424 }
1425 }
1426
1427 static void evaluate_assign_to(struct expression *left, struct symbol *type)
1428 {
1429 if (type->ctype.modifiers & MOD_CONST)
1430 expression_error(left, "assignment to const expression");
1431
1432 /* We know left is an lvalue, so it's a "preop-*" */
1433 mark_assigned(left->unop);
1434 }
1435
1436 static struct symbol *evaluate_assignment(struct expression *expr)
1437 {
1438 struct expression *left = expr->left;
1439 struct expression *where = expr;
1440 struct symbol *ltype;
1441
1442 if (!lvalue_expression(left)) {
1443 expression_error(expr, "not an lvalue");
1444 return NULL;
1445 }
1446
1447 ltype = left->ctype;
1448
1449 if (expr->op != '=') {
1450 if (!evaluate_assign_op(expr))
1451 return NULL;
1452 } else {
1453 if (!compatible_assignment_types(where, ltype, &expr->right, "assignment"))
1454 return NULL;
1455 }
1456
1457 evaluate_assign_to(left, ltype);
1458
1459 expr->ctype = ltype;
1460 return ltype;
1461 }
1462
1463 static void examine_fn_arguments(struct symbol *fn)
1464 {
1465 struct symbol *s;
1466
1467 FOR_EACH_PTR(fn->arguments, s) {
1468 struct symbol *arg = evaluate_symbol(s);
1469 /* Array/function arguments silently degenerate into pointers */
1470 if (arg) {
1471 struct symbol *ptr;
1472 switch(arg->type) {
1473 case SYM_ARRAY:
1474 case SYM_FN:
1475 ptr = alloc_symbol(s->pos, SYM_PTR);
1476 if (arg->type == SYM_ARRAY)
1477 ptr->ctype = arg->ctype;
1478 else
1479 ptr->ctype.base_type = arg;
1480 ptr->ctype.as |= s->ctype.as;
1481 ptr->ctype.modifiers |= s->ctype.modifiers & MOD_PTRINHERIT;
1482
1483 s->ctype.base_type = ptr;
1484 s->ctype.as = 0;
1485 s->ctype.modifiers &= ~MOD_PTRINHERIT;
1486 s->bit_size = 0;
1487 s->examined = 0;
1488 examine_symbol_type(s);
1489 break;
1490 default:
1491 /* nothing */
1492 break;
1493 }
1494 }
1495 } END_FOR_EACH_PTR(s);
1496 }
1497
1498 static struct symbol *convert_to_as_mod(struct symbol *sym, int as, int mod)
1499 {
1500 /* Take the modifiers of the pointer, and apply them to the member */
1501 mod |= sym->ctype.modifiers;
1502 if (sym->ctype.as != as || sym->ctype.modifiers != mod) {
1503 struct symbol *newsym = alloc_symbol(sym->pos, SYM_NODE);
1504 *newsym = *sym;
1505 newsym->ctype.as = as;
1506 newsym->ctype.modifiers = mod;
1507 sym = newsym;
1508 }
1509 return sym;
1510 }
1511
1512 static struct symbol *create_pointer(struct expression *expr, struct symbol *sym, int degenerate)
1513 {
1514 struct symbol *node = alloc_symbol(expr->pos, SYM_NODE);
1515 struct symbol *ptr = alloc_symbol(expr->pos, SYM_PTR);
1516
1517 node->ctype.base_type = ptr;
1518 ptr->bit_size = bits_in_pointer;
1519 ptr->ctype.alignment = pointer_alignment;
1520
1521 node->bit_size = bits_in_pointer;
1522 node->ctype.alignment = pointer_alignment;
1523
1524 access_symbol(sym);
1525 if (sym->ctype.modifiers & MOD_REGISTER) {
1526 warning(expr->pos, "taking address of 'register' variable '%s'", show_ident(sym->ident));
1527 sym->ctype.modifiers &= ~MOD_REGISTER;
1528 }
1529 if (sym->type == SYM_NODE) {
1530 ptr->ctype.as |= sym->ctype.as;
1531 ptr->ctype.modifiers |= sym->ctype.modifiers & MOD_PTRINHERIT;
1532 sym = sym->ctype.base_type;
1533 }
1534 if (degenerate && sym->type == SYM_ARRAY) {
1535 ptr->ctype.as |= sym->ctype.as;
1536 ptr->ctype.modifiers |= sym->ctype.modifiers & MOD_PTRINHERIT;
1537 sym = sym->ctype.base_type;
1538 }
1539 ptr->ctype.base_type = sym;
1540
1541 return node;
1542 }
1543
1544 /* Arrays degenerate into pointers on pointer arithmetic */
1545 static struct symbol *degenerate(struct expression *expr)
1546 {
1547 struct symbol *ctype, *base;
1548
1549 if (!expr)
1550 return NULL;
1551 ctype = expr->ctype;
1552 if (!ctype)
1553 return NULL;
1554 base = examine_symbol_type(ctype);
1555 if (ctype->type == SYM_NODE)
1556 base = ctype->ctype.base_type;
1557 /*
1558 * Arrays degenerate into pointers to the entries, while
1559 * functions degenerate into pointers to themselves.
1560 * If array was part of non-lvalue compound, we create a copy
1561 * of that compound first and then act as if we were dealing with
1562 * the corresponding field in there.
1563 */
1564 switch (base->type) {
1565 case SYM_ARRAY:
1566 if (expr->type == EXPR_SLICE) {
1567 struct symbol *a = alloc_symbol(expr->pos, SYM_NODE);
1568 struct expression *e0, *e1, *e2, *e3, *e4;
1569
1570 a->ctype.base_type = expr->base->ctype;
1571 a->bit_size = expr->base->ctype->bit_size;
1572 a->array_size = expr->base->ctype->array_size;
1573
1574 e0 = alloc_expression(expr->pos, EXPR_SYMBOL);
1575 e0->symbol = a;
1576 e0->ctype = &lazy_ptr_ctype;
1577
1578 e1 = alloc_expression(expr->pos, EXPR_PREOP);
1579 e1->unop = e0;
1580 e1->op = '*';
1581 e1->ctype = expr->base->ctype; /* XXX */
1582
1583 e2 = alloc_expression(expr->pos, EXPR_ASSIGNMENT);
1584 e2->left = e1;
1585 e2->right = expr->base;
1586 e2->op = '=';
1587 e2->ctype = expr->base->ctype;
1588
1589 if (expr->r_bitpos) {
1590 e3 = alloc_expression(expr->pos, EXPR_BINOP);
1591 e3->op = '+';
1592 e3->left = e0;
1593 e3->right = alloc_const_expression(expr->pos,
1594 expr->r_bitpos >> 3);
1595 e3->ctype = &lazy_ptr_ctype;
1596 } else {
1597 e3 = e0;
1598 }
1599
1600 e4 = alloc_expression(expr->pos, EXPR_COMMA);
1601 e4->left = e2;
1602 e4->right = e3;
1603 e4->ctype = &lazy_ptr_ctype;
1604
1605 expr->unop = e4;
1606 expr->type = EXPR_PREOP;
1607 expr->op = '*';
1608 }
1609 case SYM_FN:
1610 if (expr->op != '*' || expr->type != EXPR_PREOP) {
1611 expression_error(expr, "strange non-value function or array");
1612 return &bad_ctype;
1613 }
1614 *expr = *expr->unop;
1615 ctype = create_pointer(expr, ctype, 1);
1616 expr->ctype = ctype;
1617 default:
1618 /* nothing */;
1619 }
1620 return ctype;
1621 }
1622
1623 static struct symbol *evaluate_addressof(struct expression *expr)
1624 {
1625 struct expression *op = expr->unop;
1626 struct symbol *ctype;
1627
1628 if (op->op != '*' || op->type != EXPR_PREOP) {
1629 expression_error(expr, "not addressable");
1630 return NULL;
1631 }
1632 ctype = op->ctype;
1633 *expr = *op->unop;
1634 expr->flags = 0;
1635
1636 if (expr->type == EXPR_SYMBOL) {
1637 struct symbol *sym = expr->symbol;
1638 sym->ctype.modifiers |= MOD_ADDRESSABLE;
1639 }
1640
1641 /*
1642 * symbol expression evaluation is lazy about the type
1643 * of the sub-expression, so we may have to generate
1644 * the type here if so..
1645 */
1646 if (expr->ctype == &lazy_ptr_ctype) {
1647 ctype = create_pointer(expr, ctype, 0);
1648 expr->ctype = ctype;
1649 }
1650 return expr->ctype;
1651 }
1652
1653
1654 static struct symbol *evaluate_dereference(struct expression *expr)
1655 {
1656 struct expression *op = expr->unop;
1657 struct symbol *ctype = op->ctype, *node, *target;
1658
1659 /* Simplify: *&(expr) => (expr) */
1660 if (op->type == EXPR_PREOP && op->op == '&') {
1661 *expr = *op->unop;
1662 expr->flags = 0;
1663 return expr->ctype;
1664 }
1665
1666 /* Dereferencing a node drops all the node information. */
1667 if (ctype->type == SYM_NODE)
1668 ctype = ctype->ctype.base_type;
1669
1670 node = alloc_symbol(expr->pos, SYM_NODE);
1671 target = ctype->ctype.base_type;
1672
1673 switch (ctype->type) {
1674 default:
1675 expression_error(expr, "cannot dereference this type");
1676 return NULL;
1677 case SYM_PTR:
1678 node->ctype.modifiers = target->ctype.modifiers & MOD_SPECIFIER;
1679 merge_type(node, ctype);
1680 break;
1681
1682 case SYM_ARRAY:
1683 if (!lvalue_expression(op)) {
1684 expression_error(op, "non-lvalue array??");
1685 return NULL;
1686 }
1687
1688 /* Do the implied "addressof" on the array */
1689 *op = *op->unop;
1690
1691 /*
1692 * When an array is dereferenced, we need to pick
1693 * up the attributes of the original node too..
1694 */
1695 merge_type(node, op->ctype);
1696 merge_type(node, ctype);
1697 break;
1698 }
1699
1700 node->bit_size = target->bit_size;
1701 node->array_size = target->array_size;
1702
1703 expr->ctype = node;
1704 return node;
1705 }
1706
1707 /*
1708 * Unary post-ops: x++ and x--
1709 */
1710 static struct symbol *evaluate_postop(struct expression *expr)
1711 {
1712 struct expression *op = expr->unop;
1713 struct symbol *ctype = op->ctype;
1714 int class = classify_type(op->ctype, &ctype);
1715 int multiply = 0;
1716
1717 if (!lvalue_expression(expr->unop)) {
1718 expression_error(expr, "need lvalue expression for ++/--");
1719 return NULL;
1720 }
1721
1722 if ((class & TYPE_RESTRICT) && restricted_unop(expr->op, &ctype))
1723 return bad_expr_type(expr);
1724
1725 if (class & TYPE_NUM) {
1726 multiply = 1;
1727 } else if (class == TYPE_PTR) {
1728 struct symbol *target = examine_pointer_target(ctype);
1729 if (!is_function(target))
1730 multiply = target->bit_size >> 3;
1731 }
1732
1733 if (multiply) {
1734 evaluate_assign_to(op, op->ctype);
1735 expr->op_value = multiply;
1736 expr->ctype = ctype;
1737 return ctype;
1738 }
1739
1740 expression_error(expr, "bad argument type for ++/--");
1741 return NULL;
1742 }
1743
1744 static struct symbol *evaluate_sign(struct expression *expr)
1745 {
1746 struct symbol *ctype = expr->unop->ctype;
1747 int class = classify_type(ctype, &ctype);
1748 if (expr->flags && !(expr->unop->flags & Int_const_expr))
1749 expr->flags = 0;
1750 /* should be an arithmetic type */
1751 if (!(class & TYPE_NUM))
1752 return bad_expr_type(expr);
1753 if (!(class & (TYPE_FLOAT|TYPE_RESTRICT))) {
1754 struct symbol *rtype = integer_promotion(ctype);
1755 expr->unop = cast_to(expr->unop, rtype);
1756 ctype = rtype;
1757 } else if ((class & TYPE_FLOAT) && expr->op != '~') {
1758 /* no conversions needed */
1759 } else if ((class & TYPE_RESTRICT) && !restricted_unop(expr->op, &ctype)) {
1760 /* no conversions needed */
1761 } else {
1762 return bad_expr_type(expr);
1763 }
1764 if (expr->op == '+')
1765 *expr = *expr->unop;
1766 expr->ctype = ctype;
1767 return ctype;
1768 }
1769
1770 static struct symbol *evaluate_preop(struct expression *expr)
1771 {
1772 struct symbol *ctype = expr->unop->ctype;
1773
1774 switch (expr->op) {
1775 case '(':
1776 *expr = *expr->unop;
1777 return ctype;
1778
1779 case '+':
1780 case '-':
1781 case '~':
1782 return evaluate_sign(expr);
1783
1784 case '*':
1785 return evaluate_dereference(expr);
1786
1787 case '&':
1788 return evaluate_addressof(expr);
1789
1790 case SPECIAL_INCREMENT:
1791 case SPECIAL_DECREMENT:
1792 /*
1793 * From a type evaluation standpoint the preops are
1794 * the same as the postops
1795 */
1796 return evaluate_postop(expr);
1797
1798 case '!':
1799 if (expr->flags && !(expr->unop->flags & Int_const_expr))
1800 expr->flags = 0;
1801 if (is_safe_type(ctype))
1802 warning(expr->pos, "testing a 'safe expression'");
1803 if (is_float_type(ctype)) {
1804 struct expression *arg = expr->unop;
1805 expr->type = EXPR_BINOP;
1806 expr->op = SPECIAL_EQUAL;
1807 expr->left = arg;
1808 expr->right = alloc_expression(expr->pos, EXPR_FVALUE);
1809 expr->right->ctype = ctype;
1810 expr->right->fvalue = 0;
1811 } else if (is_fouled_type(ctype)) {
1812 warning(expr->pos, "%s degrades to integer",
1813 show_typename(ctype->ctype.base_type));
1814 }
1815 ctype = &bool_ctype;
1816 break;
1817
1818 default:
1819 break;
1820 }
1821 expr->ctype = ctype;
1822 return &bool_ctype;
1823 }
1824
1825 static struct symbol *find_identifier(struct ident *ident, struct symbol_list *_list, int *offset)
1826 {
1827 struct ptr_list *head = (struct ptr_list *)_list;
1828 struct ptr_list *list = head;
1829
1830 if (!head)
1831 return NULL;
1832 do {
1833 int i;
1834 for (i = 0; i < list->nr; i++) {
1835 struct symbol *sym = (struct symbol *) list->list[i];
1836 if (sym->ident) {
1837 if (sym->ident != ident)
1838 continue;
1839 *offset = sym->offset;
1840 return sym;
1841 } else {
1842 struct symbol *ctype = sym->ctype.base_type;
1843 struct symbol *sub;
1844 if (!ctype)
1845 continue;
1846 if (ctype->type != SYM_UNION && ctype->type != SYM_STRUCT)
1847 continue;
1848 sub = find_identifier(ident, ctype->symbol_list, offset);
1849 if (!sub)
1850 continue;
1851 *offset += sym->offset;
1852 return sub;
1853 }
1854 }
1855 } while ((list = list->next) != head);
1856 return NULL;
1857 }
1858
1859 static struct expression *evaluate_offset(struct expression *expr, unsigned long offset)
1860 {
1861 struct expression *add;
1862
1863 /*
1864 * Create a new add-expression
1865 *
1866 * NOTE! Even if we just add zero, we need a new node
1867 * for the member pointer, since it has a different
1868 * type than the original pointer. We could make that
1869 * be just a cast, but the fact is, a node is a node,
1870 * so we might as well just do the "add zero" here.
1871 */
1872 add = alloc_expression(expr->pos, EXPR_BINOP);
1873 add->op = '+';
1874 add->left = expr;
1875 add->right = alloc_expression(expr->pos, EXPR_VALUE);
1876 add->right->ctype = &int_ctype;
1877 add->right->value = offset;
1878
1879 /*
1880 * The ctype of the pointer will be lazily evaluated if
1881 * we ever take the address of this member dereference..
1882 */
1883 add->ctype = &lazy_ptr_ctype;
1884 return add;
1885 }
1886
1887 /* structure/union dereference */
1888 static struct symbol *evaluate_member_dereference(struct expression *expr)
1889 {
1890 int offset;
1891 struct symbol *ctype, *member;
1892 struct expression *deref = expr->deref, *add;
1893 struct ident *ident = expr->member;
1894 unsigned int mod;
1895 int address_space;
1896
1897 if (!evaluate_expression(deref))
1898 return NULL;
1899 if (!ident) {
1900 expression_error(expr, "bad member name");
1901 return NULL;
1902 }
1903
1904 ctype = deref->ctype;
1905 examine_symbol_type(ctype);
1906 address_space = ctype->ctype.as;
1907 mod = ctype->ctype.modifiers;
1908 if (ctype->type == SYM_NODE) {
1909 ctype = ctype->ctype.base_type;
1910 address_space |= ctype->ctype.as;
1911 mod |= ctype->ctype.modifiers;
1912 }
1913 if (!ctype || (ctype->type != SYM_STRUCT && ctype->type != SYM_UNION)) {
1914 expression_error(expr, "expected structure or union");
1915 return NULL;
1916 }
1917 offset = 0;
1918 member = find_identifier(ident, ctype->symbol_list, &offset);
1919 if (!member) {
1920 const char *type = ctype->type == SYM_STRUCT ? "struct" : "union";
1921 const char *name = "<unnamed>";
1922 int namelen = 9;
1923 if (ctype->ident) {
1924 name = ctype->ident->name;
1925 namelen = ctype->ident->len;
1926 }
1927 if (ctype->symbol_list)
1928 expression_error(expr, "no member '%s' in %s %.*s",
1929 show_ident(ident), type, namelen, name);
1930 else
1931 expression_error(expr, "using member '%s' in "
1932 "incomplete %s %.*s", show_ident(ident),
1933 type, namelen, name);
1934 return NULL;
1935 }
1936
1937 /*
1938 * The member needs to take on the address space and modifiers of
1939 * the "parent" type.
1940 */
1941 member = convert_to_as_mod(member, address_space, mod);
1942 ctype = get_base_type(member);
1943
1944 if (!lvalue_expression(deref)) {
1945 if (deref->type != EXPR_SLICE) {
1946 expr->base = deref;
1947 expr->r_bitpos = 0;
1948 } else {
1949 expr->base = deref->base;
1950 expr->r_bitpos = deref->r_bitpos;
1951 }
1952 expr->r_bitpos += offset << 3;
1953 expr->type = EXPR_SLICE;
1954 expr->r_nrbits = member->bit_size;
1955 expr->r_bitpos += member->bit_offset;
1956 expr->ctype = member;
1957 return member;
1958 }
1959
1960 deref = deref->unop;
1961 expr->deref = deref;
1962
1963 add = evaluate_offset(deref, offset);
1964 expr->type = EXPR_PREOP;
1965 expr->op = '*';
1966 expr->unop = add;
1967
1968 expr->ctype = member;
1969 return member;
1970 }
1971
1972 static int is_promoted(struct expression *expr)
1973 {
1974 while (1) {
1975 switch (expr->type) {
1976 case EXPR_BINOP:
1977 case EXPR_SELECT:
1978 case EXPR_CONDITIONAL:
1979 return 1;
1980 case EXPR_COMMA:
1981 expr = expr->right;
1982 continue;
1983 case EXPR_PREOP:
1984 switch (expr->op) {
1985 case '(':
1986 expr = expr->unop;
1987 continue;
1988 case '+':
1989 case '-':
1990 case '~':
1991 return 1;
1992 default:
1993 return 0;
1994 }
1995 default:
1996 return 0;
1997 }
1998 }
1999 }
2000
2001
2002 static struct symbol *evaluate_cast(struct expression *);
2003
2004 static struct symbol *evaluate_type_information(struct expression *expr)
2005 {
2006 struct symbol *sym = expr->cast_type;
2007 if (!sym) {
2008 sym = evaluate_expression(expr->cast_expression);
2009 if (!sym)
2010 return NULL;
2011 /*
2012 * Expressions of restricted types will possibly get
2013 * promoted - check that here
2014 */
2015 if (is_restricted_type(sym)) {
2016 if (sym->bit_size < bits_in_int && is_promoted(expr))
2017 sym = &int_ctype;
2018 } else if (is_fouled_type(sym)) {
2019 sym = &int_ctype;
2020 }
2021 }
2022 examine_symbol_type(sym);
2023 if (is_bitfield_type(sym)) {
2024 expression_error(expr, "trying to examine bitfield type");
2025 return NULL;
2026 }
2027 return sym;
2028 }
2029
2030 static struct symbol *evaluate_sizeof(struct expression *expr)
2031 {
2032 struct symbol *type;
2033 int size;
2034
2035 type = evaluate_type_information(expr);
2036 if (!type)
2037 return NULL;
2038
2039 size = type->bit_size;
2040 if ((size < 0) || (size & 7))
2041 expression_error(expr, "cannot size expression");
2042 expr->type = EXPR_VALUE;
2043 expr->value = size >> 3;
2044 expr->taint = 0;
2045 expr->ctype = size_t_ctype;
2046 return size_t_ctype;
2047 }
2048
2049 static struct symbol *evaluate_ptrsizeof(struct expression *expr)
2050 {
2051 struct symbol *type;
2052 int size;
2053
2054 type = evaluate_type_information(expr);
2055 if (!type)
2056 return NULL;
2057
2058 if (type->type == SYM_NODE)
2059 type = type->ctype.base_type;
2060 if (!type)
2061 return NULL;
2062 switch (type->type) {
2063 case SYM_ARRAY:
2064 break;
2065 case SYM_PTR:
2066 type = get_base_type(type);
2067 if (type)
2068 break;
2069 default:
2070 expression_error(expr, "expected pointer expression");
2071 return NULL;
2072 }
2073 size = type->bit_size;
2074 if (size & 7)
2075 size = 0;
2076 expr->type = EXPR_VALUE;
2077 expr->value = size >> 3;
2078 expr->taint = 0;
2079 expr->ctype = size_t_ctype;
2080 return size_t_ctype;
2081 }
2082
2083 static struct symbol *evaluate_alignof(struct expression *expr)
2084 {
2085 struct symbol *type;
2086
2087 type = evaluate_type_information(expr);
2088 if (!type)
2089 return NULL;
2090
2091 expr->type = EXPR_VALUE;
2092 expr->value = type->ctype.alignment;
2093 expr->taint = 0;
2094 expr->ctype = size_t_ctype;
2095 return size_t_ctype;
2096 }
2097
2098 static int evaluate_arguments(struct symbol *f, struct symbol *fn, struct expression_list *head)
2099 {
2100 struct expression *expr;
2101 struct symbol_list *argument_types = fn->arguments;
2102 struct symbol *argtype;
2103 int i = 1;
2104
2105 PREPARE_PTR_LIST(argument_types, argtype);
2106 FOR_EACH_PTR (head, expr) {
2107 struct expression **p = THIS_ADDRESS(expr);
2108 struct symbol *ctype, *target;
2109 ctype = evaluate_expression(expr);
2110
2111 if (!ctype)
2112 return 0;
2113
2114 target = argtype;
2115 if (!target) {
2116 struct symbol *type;
2117 int class = classify_type(ctype, &type);
2118 if (is_int(class)) {
2119 *p = cast_to(expr, integer_promotion(type));
2120 } else if (class & TYPE_FLOAT) {
2121 unsigned long mod = type->ctype.modifiers;
2122 if (!(mod & (MOD_LONG|MOD_LONGLONG)))
2123 *p = cast_to(expr, &double_ctype);
2124 } else if (class & TYPE_PTR) {
2125 if (expr->ctype == &null_ctype)
2126 *p = cast_to(expr, &ptr_ctype);
2127 else
2128 degenerate(expr);
2129 }
2130 } else {
2131 static char where[30];
2132 examine_symbol_type(target);
2133 sprintf(where, "argument %d", i);
2134 compatible_assignment_types(expr, target, p, where);
2135 }
2136
2137 i++;
2138 NEXT_PTR_LIST(argtype);
2139 } END_FOR_EACH_PTR(expr);
2140 FINISH_PTR_LIST(argtype);
2141 return 1;
2142 }
2143
2144 static struct symbol *find_struct_ident(struct symbol *ctype, struct ident *ident)
2145 {
2146 struct symbol *sym;
2147
2148 FOR_EACH_PTR(ctype->symbol_list, sym) {
2149 if (sym->ident == ident)
2150 return sym;
2151 } END_FOR_EACH_PTR(sym);
2152 return NULL;
2153 }
2154
2155 static void convert_index(struct expression *e)
2156 {
2157 struct expression *child = e->idx_expression;
2158 unsigned from = e->idx_from;
2159 unsigned to = e->idx_to + 1;
2160 e->type = EXPR_POS;
2161 e->init_offset = from * (e->ctype->bit_size>>3);
2162 e->init_nr = to - from;
2163 e->init_expr = child;
2164 }
2165
2166 static void convert_ident(struct expression *e)
2167 {
2168 struct expression *child = e->ident_expression;
2169 struct symbol *sym = e->field;
2170 e->type = EXPR_POS;
2171 e->init_offset = sym->offset;
2172 e->init_nr = 1;
2173 e->init_expr = child;
2174 }
2175
2176 static void convert_designators(struct expression *e)
2177 {
2178 while (e) {
2179 if (e->type == EXPR_INDEX)
2180 convert_index(e);
2181 else if (e->type == EXPR_IDENTIFIER)
2182 convert_ident(e);
2183 else
2184 break;
2185 e = e->init_expr;
2186 }
2187 }
2188
2189 static void excess(struct expression *e, const char *s)
2190 {
2191 warning(e->pos, "excessive elements in %s initializer", s);
2192 }
2193
2194 /*
2195 * implicit designator for the first element
2196 */
2197 static struct expression *first_subobject(struct symbol *ctype, int class,
2198 struct expression **v)
2199 {
2200 struct expression *e = *v, *new;
2201
2202 if (ctype->type == SYM_NODE)
2203 ctype = ctype->ctype.base_type;
2204
2205 if (class & TYPE_PTR) { /* array */
2206 if (!ctype->bit_size)
2207 return NULL;
2208 new = alloc_expression(e->pos, EXPR_INDEX);
2209 new->idx_expression = e;
2210 new->ctype = ctype->ctype.base_type;
2211 } else {
2212 struct symbol *field, *p;
2213 PREPARE_PTR_LIST(ctype->symbol_list, p);
2214 while (p && !p->ident && is_bitfield_type(p))
2215 NEXT_PTR_LIST(p);
2216 field = p;
2217 FINISH_PTR_LIST(p);
2218 if (!field)
2219 return NULL;
2220 new = alloc_expression(e->pos, EXPR_IDENTIFIER);
2221 new->ident_expression = e;
2222 new->field = new->ctype = field;
2223 }
2224 *v = new;
2225 return new;
2226 }
2227
2228 /*
2229 * sanity-check explicit designators; return the innermost one or NULL
2230 * in case of error. Assign types.
2231 */
2232 static struct expression *check_designators(struct expression *e,
2233 struct symbol *ctype)
2234 {
2235 struct expression *last = NULL;
2236 const char *err;
2237 while (1) {
2238 if (ctype->type == SYM_NODE)
2239 ctype = ctype->ctype.base_type;
2240 if (e->type == EXPR_INDEX) {
2241 struct symbol *type;
2242 if (ctype->type != SYM_ARRAY) {
2243 err = "array index in non-array";
2244 break;
2245 }
2246 type = ctype->ctype.base_type;
2247 if (ctype->bit_size >= 0 && type->bit_size >= 0) {
2248 unsigned offset = e->idx_to * type->bit_size;
2249 if (offset >= ctype->bit_size) {
2250 err = "index out of bounds in";
2251 break;
2252 }
2253 }
2254 e->ctype = ctype = type;
2255 ctype = type;
2256 last = e;
2257 if (!e->idx_expression) {
2258 err = "invalid";
2259 break;
2260 }
2261 e = e->idx_expression;
2262 } else if (e->type == EXPR_IDENTIFIER) {
2263 if (ctype->type != SYM_STRUCT && ctype->type != SYM_UNION) {
2264 err = "field name not in struct or union";
2265 break;
2266 }
2267 ctype = find_struct_ident(ctype, e->expr_ident);
2268 if (!ctype) {
2269 err = "unknown field name in";
2270 break;
2271 }
2272 e->field = e->ctype = ctype;
2273 last = e;
2274 if (!e->ident_expression) {
2275 err = "invalid";
2276 break;
2277 }
2278 e = e->ident_expression;
2279 } else if (e->type == EXPR_POS) {
2280 err = "internal front-end error: EXPR_POS in";
2281 break;
2282 } else
2283 return last;
2284 }
2285 expression_error(e, "%s initializer", err);
2286 return NULL;
2287 }
2288
2289 /*
2290 * choose the next subobject to initialize.
2291 *
2292 * Get designators for next element, switch old ones to EXPR_POS.
2293 * Return the resulting expression or NULL if we'd run out of subobjects.
2294 * The innermost designator is returned in *v. Designators in old
2295 * are assumed to be already sanity-checked.
2296 */
2297 static struct expression *next_designators(struct expression *old,
2298 struct symbol *ctype,
2299 struct expression *e, struct expression **v)
2300 {
2301 struct expression *new = NULL;
2302
2303 if (!old)
2304 return NULL;
2305 if (old->type == EXPR_INDEX) {
2306 struct expression *copy;
2307 unsigned n;
2308
2309 copy = next_designators(old->idx_expression,
2310 old->ctype, e, v);
2311 if (!copy) {
2312 n = old->idx_to + 1;
2313 if (n * old->ctype->bit_size == ctype->bit_size) {
2314 convert_index(old);
2315 return NULL;
2316 }
2317 copy = e;
2318 *v = new = alloc_expression(e->pos, EXPR_INDEX);
2319 } else {
2320 n = old->idx_to;
2321 new = alloc_expression(e->pos, EXPR_INDEX);
2322 }
2323
2324 new->idx_from = new->idx_to = n;
2325 new->idx_expression = copy;
2326 new->ctype = old->ctype;
2327 convert_index(old);
2328 } else if (old->type == EXPR_IDENTIFIER) {
2329 struct expression *copy;
2330 struct symbol *field;
2331
2332 copy = next_designators(old->ident_expression,
2333 old->ctype, e, v);
2334 if (!copy) {
2335 field = old->field->next_subobject;
2336 if (!field) {
2337 convert_ident(old);
2338 return NULL;
2339 }
2340 copy = e;
2341 *v = new = alloc_expression(e->pos, EXPR_IDENTIFIER);
2342 } else {
2343 field = old->field;
2344 new = alloc_expression(e->pos, EXPR_IDENTIFIER);
2345 }
2346
2347 new->field = field;
2348 new->expr_ident = field->ident;
2349 new->ident_expression = copy;
2350 new->ctype = field;
2351 convert_ident(old);
2352 }
2353 return new;
2354 }
2355
2356 static int handle_simple_initializer(struct expression **ep, int nested,
2357 int class, struct symbol *ctype);
2358
2359 /*
2360 * deal with traversing subobjects [6.7.8(17,18,20)]
2361 */
2362 static void handle_list_initializer(struct expression *expr,
2363 int class, struct symbol *ctype)
2364 {
2365 struct expression *e, *last = NULL, *top = NULL, *next;
2366 int jumped = 0;
2367
2368 FOR_EACH_PTR(expr->expr_list, e) {
2369 struct expression **v;
2370 struct symbol *type;
2371 int lclass;
2372
2373 if (e->type != EXPR_INDEX && e->type != EXPR_IDENTIFIER) {
2374 if (!top) {
2375 top = e;
2376 last = first_subobject(ctype, class, &top);
2377 } else {
2378 last = next_designators(last, ctype, e, &top);
2379 }
2380 if (!last) {
2381 excess(e, class & TYPE_PTR ? "array" :
2382 "struct or union");
2383 DELETE_CURRENT_PTR(e);
2384 continue;
2385 }
2386 if (jumped) {
2387 warning(e->pos, "advancing past deep designator");
2388 jumped = 0;
2389 }
2390 REPLACE_CURRENT_PTR(e, last);
2391 } else {
2392 next = check_designators(e, ctype);
2393 if (!next) {
2394 DELETE_CURRENT_PTR(e);
2395 continue;
2396 }
2397 top = next;
2398 /* deeper than one designator? */
2399 jumped = top != e;
2400 convert_designators(last);
2401 last = e;
2402 }
2403
2404 found:
2405 lclass = classify_type(top->ctype, &type);
2406 if (top->type == EXPR_INDEX)
2407 v = &top->idx_expression;
2408 else
2409 v = &top->ident_expression;
2410
2411 if (handle_simple_initializer(v, 1, lclass, top->ctype))
2412 continue;
2413
2414 if (!(lclass & TYPE_COMPOUND)) {
2415 warning(e->pos, "bogus scalar initializer");
2416 DELETE_CURRENT_PTR(e);
2417 continue;
2418 }
2419
2420 next = first_subobject(type, lclass, v);
2421 if (next) {
2422 warning(e->pos, "missing braces around initializer");
2423 top = next;
2424 goto found;
2425 }
2426
2427 DELETE_CURRENT_PTR(e);
2428 excess(e, lclass & TYPE_PTR ? "array" : "struct or union");
2429
2430 } END_FOR_EACH_PTR(e);
2431
2432 convert_designators(last);
2433 expr->ctype = ctype;
2434 }
2435
2436 static int is_string_literal(struct expression **v)
2437 {
2438 struct expression *e = *v;
2439 while (e && e->type == EXPR_PREOP && e->op == '(')
2440 e = e->unop;
2441 if (!e || e->type != EXPR_STRING)
2442 return 0;
2443 if (e != *v && Wparen_string)
2444 warning(e->pos,
2445 "array initialized from parenthesized string constant");
2446 *v = e;
2447 return 1;
2448 }
2449
2450 /*
2451 * We want a normal expression, possibly in one layer of braces. Warn
2452 * if the latter happens inside a list (it's legal, but likely to be
2453 * an effect of screwup). In case of anything not legal, we are definitely
2454 * having an effect of screwup, so just fail and let the caller warn.
2455 */
2456 static struct expression *handle_scalar(struct expression *e, int nested)
2457 {
2458 struct expression *v = NULL, *p;
2459 int count = 0;
2460
2461 /* normal case */
2462 if (e->type != EXPR_INITIALIZER)
2463 return e;
2464
2465 FOR_EACH_PTR(e->expr_list, p) {
2466 if (!v)
2467 v = p;
2468 count++;
2469 } END_FOR_EACH_PTR(p);
2470 if (count != 1)
2471 return NULL;
2472 switch(v->type) {
2473 case EXPR_INITIALIZER:
2474 case EXPR_INDEX:
2475 case EXPR_IDENTIFIER:
2476 return NULL;
2477 default:
2478 break;
2479 }
2480 if (nested)
2481 warning(e->pos, "braces around scalar initializer");
2482 return v;
2483 }
2484
2485 /*
2486 * deal with the cases that don't care about subobjects:
2487 * scalar <- assignment expression, possibly in braces [6.7.8(11)]
2488 * character array <- string literal, possibly in braces [6.7.8(14)]
2489 * struct or union <- assignment expression of compatible type [6.7.8(13)]
2490 * compound type <- initializer list in braces [6.7.8(16)]
2491 * The last one punts to handle_list_initializer() which, in turn will call
2492 * us for individual elements of the list.
2493 *
2494 * We do not handle 6.7.8(15) (wide char array <- wide string literal) for
2495 * the lack of support of wide char stuff in general.
2496 *
2497 * One note: we need to take care not to evaluate a string literal until
2498 * we know that we *will* handle it right here. Otherwise we would screw
2499 * the cases like struct { struct {char s[10]; ...} ...} initialized with
2500 * { "string", ...} - we need to preserve that string literal recognizable
2501 * until we dig into the inner struct.
2502 */
2503 static int handle_simple_initializer(struct expression **ep, int nested,
2504 int class, struct symbol *ctype)
2505 {
2506 int is_string = is_string_type(ctype);
2507 struct expression *e = *ep, *p;
2508 struct symbol *type;
2509
2510 if (!e)
2511 return 0;
2512
2513 /* scalar */
2514 if (!(class & TYPE_COMPOUND)) {
2515 e = handle_scalar(e, nested);
2516 if (!e)
2517 return 0;
2518 *ep = e;
2519 if (!evaluate_expression(e))
2520 return 1;
2521 compatible_assignment_types(e, ctype, ep, "initializer");
2522 return 1;
2523 }
2524
2525 /*
2526 * sublist; either a string, or we dig in; the latter will deal with
2527 * pathologies, so we don't need anything fancy here.
2528 */
2529 if (e->type == EXPR_INITIALIZER) {
2530 if (is_string) {
2531 struct expression *v = NULL;
2532 int count = 0;
2533
2534 FOR_EACH_PTR(e->expr_list, p) {
2535 if (!v)
2536 v = p;
2537 count++;
2538 } END_FOR_EACH_PTR(p);
2539 if (count == 1 && is_string_literal(&v)) {
2540 *ep = e = v;
2541 goto String;
2542 }
2543 }
2544 handle_list_initializer(e, class, ctype);
2545 return 1;
2546 }
2547
2548 /* string */
2549 if (is_string_literal(&e)) {
2550 /* either we are doing array of char, or we'll have to dig in */
2551 if (is_string) {
2552 *ep = e;
2553 goto String;
2554 }
2555 return 0;
2556 }
2557 /* struct or union can be initialized by compatible */
2558 if (class != TYPE_COMPOUND)
2559 return 0;
2560 type = evaluate_expression(e);
2561 if (!type)
2562 return 0;
2563 if (ctype->type == SYM_NODE)
2564 ctype = ctype->ctype.base_type;
2565 if (type->type == SYM_NODE)
2566 type = type->ctype.base_type;
2567 if (ctype == type)
2568 return 1;
2569 return 0;
2570
2571 String:
2572 p = alloc_expression(e->pos, EXPR_STRING);
2573 *p = *e;
2574 type = evaluate_expression(p);
2575 if (ctype->bit_size != -1 &&
2576 ctype->bit_size + bits_in_char < type->bit_size) {
2577 warning(e->pos,
2578 "too long initializer-string for array of char");
2579 }
2580 *ep = p;
2581 return 1;
2582 }
2583
2584 static void evaluate_initializer(struct symbol *ctype, struct expression **ep)
2585 {
2586 struct symbol *type;
2587 int class = classify_type(ctype, &type);
2588 if (!handle_simple_initializer(ep, 0, class, ctype))
2589 expression_error(*ep, "invalid initializer");
2590 }
2591
2592 static struct symbol *evaluate_cast(struct expression *expr)
2593 {
2594 struct expression *target = expr->cast_expression;
2595 struct symbol *ctype;
2596 struct symbol *t1, *t2;
2597 int class1, class2;
2598 int as1 = 0, as2 = 0;
2599
2600 if (!target)
2601 return NULL;
2602
2603 /*
2604 * Special case: a cast can be followed by an
2605 * initializer, in which case we need to pass
2606 * the type value down to that initializer rather
2607 * than trying to evaluate it as an expression
2608 *
2609 * A more complex case is when the initializer is
2610 * dereferenced as part of a post-fix expression.
2611 * We need to produce an expression that can be dereferenced.
2612 */
2613 if (target->type == EXPR_INITIALIZER) {
2614 struct symbol *sym = expr->cast_type;
2615 struct expression *addr = alloc_expression(expr->pos, EXPR_SYMBOL);
2616
2617 sym->initializer = target;
2618 evaluate_symbol(sym);
2619
2620 addr->ctype = &lazy_ptr_ctype; /* Lazy eval */
2621 addr->symbol = sym;
2622
2623 expr->type = EXPR_PREOP;
2624 expr->op = '*';
2625 expr->unop = addr;
2626 expr->ctype = sym;
2627
2628 return sym;
2629 }
2630
2631 ctype = examine_symbol_type(expr->cast_type);
2632 expr->ctype = ctype;
2633 expr->cast_type = ctype;
2634
2635 evaluate_expression(target);
2636 degenerate(target);
2637
2638 class1 = classify_type(ctype, &t1);
2639
2640 /* cast to non-integer type -> not an integer constant expression */
2641 if (!is_int(class1))
2642 expr->flags = 0;
2643 /* if argument turns out to be not an integer constant expression *and*
2644 it was not a floating literal to start with -> too bad */
2645 else if (expr->flags == Int_const_expr &&
2646 !(target->flags & Int_const_expr))
2647 expr->flags = 0;
2648 /*
2649 * You can always throw a value away by casting to
2650 * "void" - that's an implicit "force". Note that
2651 * the same is _not_ true of "void *".
2652 */
2653 if (t1 == &void_ctype)
2654 goto out;
2655
2656 if (class1 & (TYPE_COMPOUND | TYPE_FN))
2657 warning(expr->pos, "cast to non-scalar");
2658
2659 t2 = target->ctype;
2660 if (!t2) {
2661 expression_error(expr, "cast from unknown type");
2662 goto out;
2663 }
2664 class2 = classify_type(t2, &t2);
2665
2666 if (class2 & TYPE_COMPOUND)
2667 warning(expr->pos, "cast from non-scalar");
2668
2669 if (expr->type == EXPR_FORCE_CAST)
2670 goto out;
2671
2672 /* allowed cast unfouls */
2673 if (class2 & TYPE_FOULED)
2674 t2 = unfoul(t2);
2675
2676 if (t1 != t2) {
2677 if (class1 & TYPE_RESTRICT)
2678 warning(expr->pos, "cast to %s",
2679 show_typename(t1));
2680 if (class2 & TYPE_RESTRICT)
2681 warning(expr->pos, "cast from %s",
2682 show_typename(t2));
2683 }
2684
2685 if (t1 == &ulong_ctype)
2686 as1 = -1;
2687 else if (class1 == TYPE_PTR) {
2688 examine_pointer_target(t1);
2689 as1 = t1->ctype.as;
2690 }
2691
2692 if (t2 == &ulong_ctype)
2693 as2 = -1;
2694 else if (class2 == TYPE_PTR) {
2695 examine_pointer_target(t2);
2696 as2 = t2->ctype.as;
2697 }
2698
2699 if (!as1 && as2 > 0)
2700 warning(expr->pos, "cast removes address space of expression");
2701 if (as1 > 0 && as2 > 0 && as1 != as2)
2702 warning(expr->pos, "cast between address spaces (<asn:%d>-><asn:%d>)", as2, as1);
2703 if (as1 > 0 && !as2 &&
2704 !is_null_pointer_constant(target) && Wcast_to_as)
2705 warning(expr->pos,
2706 "cast adds address space to expression (<asn:%d>)", as1);
2707
2708 if (!(t1->ctype.modifiers & MOD_PTRINHERIT) && class1 == TYPE_PTR &&
2709 !as1 && (target->flags & Int_const_expr)) {
2710 if (t1->ctype.base_type == &void_ctype) {
2711 if (is_zero_constant(target)) {
2712 /* NULL */
2713 expr->type = EXPR_VALUE;
2714 expr->ctype = &null_ctype;
2715 expr->value = 0;
2716 return ctype;
2717 }
2718 }
2719 }
2720 out:
2721 return ctype;
2722 }
2723
2724 /*
2725 * Evaluate a call expression with a symbol. This
2726 * should expand inline functions, and evaluate
2727 * builtins.
2728 */
2729 static int evaluate_symbol_call(struct expression *expr)
2730 {
2731 struct expression *fn = expr->fn;
2732 struct symbol *ctype = fn->ctype;
2733
2734 if (fn->type != EXPR_PREOP)
2735 return 0;
2736
2737 if (ctype->op && ctype->op->evaluate)
2738 return ctype->op->evaluate(expr);
2739
2740 if (ctype->ctype.modifiers & MOD_INLINE) {
2741 int ret;
2742 struct symbol *curr = current_fn;
2743 current_fn = ctype->ctype.base_type;
2744
2745 ret = inline_function(expr, ctype);
2746
2747 /* restore the old function */
2748 current_fn = curr;
2749 return ret;
2750 }
2751
2752 return 0;
2753 }
2754
2755 static struct symbol *evaluate_call(struct expression *expr)
2756 {
2757 int args, fnargs;
2758 struct symbol *ctype, *sym;
2759 struct expression *fn = expr->fn;
2760 struct expression_list *arglist = expr->args;
2761
2762 if (!evaluate_expression(fn))
2763 return NULL;
2764 sym = ctype = fn->ctype;
2765 if (ctype->type == SYM_NODE)
2766 ctype = ctype->ctype.base_type;
2767 if (ctype->type == SYM_PTR)
2768 ctype = get_base_type(ctype);
2769
2770 if (ctype->type != SYM_FN) {
2771 struct expression *arg;
2772 expression_error(expr, "not a function %s",
2773 show_ident(sym->ident));
2774 /* do typechecking in arguments */
2775 FOR_EACH_PTR (arglist, arg) {
2776 evaluate_expression(arg);
2777 } END_FOR_EACH_PTR(arg);
2778 return NULL;
2779 }
2780
2781 examine_fn_arguments(ctype);
2782 if (sym->type == SYM_NODE && fn->type == EXPR_PREOP &&
2783 sym->op && sym->op->args) {
2784 if (!sym->op->args(expr))
2785 return NULL;
2786 } else {
2787 if (!evaluate_arguments(sym, ctype, arglist))
2788 return NULL;
2789 args = expression_list_size(expr->args);
2790 fnargs = symbol_list_size(ctype->arguments);
2791 if (args < fnargs)
2792 expression_error(expr,
2793 "not enough arguments for function %s",
2794 show_ident(sym->ident));
2795 if (args > fnargs && !ctype->variadic)
2796 expression_error(expr,
2797 "too many arguments for function %s",
2798 show_ident(sym->ident));
2799 }
2800 if (sym->type == SYM_NODE) {
2801 if (evaluate_symbol_call(expr))
2802 return expr->ctype;
2803 }
2804 expr->ctype = ctype->ctype.base_type;
2805 return expr->ctype;
2806 }
2807
2808 static struct symbol *evaluate_offsetof(struct expression *expr)
2809 {
2810 struct expression *e = expr->down;
2811 struct symbol *ctype = expr->in;
2812 int class;
2813
2814 if (expr->op == '.') {
2815 struct symbol *field;
2816 int offset = 0;
2817 if (!ctype) {
2818 expression_error(expr, "expected structure or union");
2819 return NULL;
2820 }
2821 examine_symbol_type(ctype);
2822 class = classify_type(ctype, &ctype);
2823 if (class != TYPE_COMPOUND) {
2824 expression_error(expr, "expected structure or union");
2825 return NULL;
2826 }
2827
2828 field = find_identifier(expr->ident, ctype->symbol_list, &offset);
2829 if (!field) {
2830 expression_error(expr, "unknown member");
2831 return NULL;
2832 }
2833 ctype = field;
2834 expr->type = EXPR_VALUE;
2835 expr->flags = Int_const_expr;
2836 expr->value = offset;
2837 expr->taint = 0;
2838 expr->ctype = size_t_ctype;
2839 } else {
2840 if (!ctype) {
2841 expression_error(expr, "expected structure or union");
2842 return NULL;
2843 }
2844 examine_symbol_type(ctype);
2845 class = classify_type(ctype, &ctype);
2846 if (class != (TYPE_COMPOUND | TYPE_PTR)) {
2847 expression_error(expr, "expected array");
2848 return NULL;
2849 }
2850 ctype = ctype->ctype.base_type;
2851 if (!expr->index) {
2852 expr->type = EXPR_VALUE;
2853 expr->flags = Int_const_expr;
2854 expr->value = 0;
2855 expr->taint = 0;
2856 expr->ctype = size_t_ctype;
2857 } else {
2858 struct expression *idx = expr->index, *m;
2859 struct symbol *i_type = evaluate_expression(idx);
2860 int i_class = classify_type(i_type, &i_type);
2861 if (!is_int(i_class)) {
2862 expression_error(expr, "non-integer index");
2863 return NULL;
2864 }
2865 unrestrict(idx, i_class, &i_type);
2866 idx = cast_to(idx, size_t_ctype);
2867 m = alloc_const_expression(expr->pos,
2868 ctype->bit_size >> 3);
2869 m->ctype = size_t_ctype;
2870 m->flags = Int_const_expr;
2871 expr->type = EXPR_BINOP;
2872 expr->left = idx;
2873 expr->right = m;
2874 expr->op = '*';
2875 expr->ctype = size_t_ctype;
2876 expr->flags = m->flags & idx->flags & Int_const_expr;
2877 }
2878 }
2879 if (e) {
2880 struct expression *copy = __alloc_expression(0);
2881 *copy = *expr;
2882 if (e->type == EXPR_OFFSETOF)
2883 e->in = ctype;
2884 if (!evaluate_expression(e))
2885 return NULL;
2886 expr->type = EXPR_BINOP;
2887 expr->flags = e->flags & copy->flags & Int_const_expr;
2888 expr->op = '+';
2889 expr->ctype = size_t_ctype;
2890 expr->left = copy;
2891 expr->right = e;
2892 }
2893 return size_t_ctype;
2894 }
2895
2896 struct symbol *evaluate_expression(struct expression *expr)
2897 {
2898 if (!expr)
2899 return NULL;
2900 if (expr->ctype)
2901 return expr->ctype;
2902
2903 switch (expr->type) {
2904 case EXPR_VALUE:
2905 case EXPR_FVALUE:
2906 expression_error(expr, "value expression without a type");
2907 return NULL;
2908 case EXPR_STRING:
2909 return evaluate_string(expr);
2910 case EXPR_SYMBOL:
2911 return evaluate_symbol_expression(expr);
2912 case EXPR_BINOP:
2913 if (!evaluate_expression(expr->left))
2914 return NULL;
2915 if (!evaluate_expression(expr->right))
2916 return NULL;
2917 return evaluate_binop(expr);
2918 case EXPR_LOGICAL:
2919 return evaluate_logical(expr);
2920 case EXPR_COMMA:
2921 evaluate_expression(expr->left);
2922 if (!evaluate_expression(expr->right))
2923 return NULL;
2924 return evaluate_comma(expr);
2925 case EXPR_COMPARE:
2926 if (!evaluate_expression(expr->left))
2927 return NULL;
2928 if (!evaluate_expression(expr->right))
2929 return NULL;
2930 return evaluate_compare(expr);
2931 case EXPR_ASSIGNMENT:
2932 if (!evaluate_expression(expr->left))
2933 return NULL;
2934 if (!evaluate_expression(expr->right))
2935 return NULL;
2936 return evaluate_assignment(expr);
2937 case EXPR_PREOP:
2938 if (!evaluate_expression(expr->unop))
2939 return NULL;
2940 return evaluate_preop(expr);
2941 case EXPR_POSTOP:
2942 if (!evaluate_expression(expr->unop))
2943 return NULL;
2944 return evaluate_postop(expr);
2945 case EXPR_CAST:
2946 case EXPR_FORCE_CAST:
2947 case EXPR_IMPLIED_CAST:
2948 return evaluate_cast(expr);
2949 case EXPR_SIZEOF:
2950 return evaluate_sizeof(expr);
2951 case EXPR_PTRSIZEOF:
2952 return evaluate_ptrsizeof(expr);
2953 case EXPR_ALIGNOF:
2954 return evaluate_alignof(expr);
2955 case EXPR_DEREF:
2956 return evaluate_member_dereference(expr);
2957 case EXPR_CALL:
2958 return evaluate_call(expr);
2959 case EXPR_SELECT:
2960 case EXPR_CONDITIONAL:
2961 return evaluate_conditional_expression(expr);
2962 case EXPR_STATEMENT:
2963 expr->ctype = evaluate_statement(expr->statement);
2964 return expr->ctype;
2965
2966 case EXPR_LABEL:
2967 expr->ctype = &ptr_ctype;
2968 return &ptr_ctype;
2969
2970 case EXPR_TYPE:
2971 /* Evaluate the type of the symbol .. */
2972 evaluate_symbol(expr->symbol);
2973 /* .. but the type of the _expression_ is a "type" */
2974 expr->ctype = &type_ctype;
2975 return &type_ctype;
2976
2977 case EXPR_OFFSETOF:
2978 return evaluate_offsetof(expr);
2979
2980 /* These can not exist as stand-alone expressions */
2981 case EXPR_INITIALIZER:
2982 case EXPR_IDENTIFIER:
2983 case EXPR_INDEX:
2984 case EXPR_POS:
2985 expression_error(expr, "internal front-end error: initializer in expression");
2986 return NULL;
2987 case EXPR_SLICE:
2988 expression_error(expr, "internal front-end error: SLICE re-evaluated");
2989 return NULL;
2990 }
2991 return NULL;
2992 }
2993
2994 static void check_duplicates(struct symbol *sym)
2995 {
2996 int declared = 0;
2997 struct symbol *next = sym;
2998
2999 while ((next = next->same_symbol) != NULL) {
3000 const char *typediff;
3001 evaluate_symbol(next);
3002 declared++;
3003 typediff = type_difference(&sym->ctype, &next->ctype, 0, 0);
3004 if (typediff) {
3005 sparse_error(sym->pos, "symbol '%s' redeclared with different type (originally declared at %s:%d) - %s",
3006 show_ident(sym->ident),
3007 stream_name(next->pos.stream), next->pos.line, typediff);
3008 return;
3009 }
3010 }
3011 if (!declared) {
3012 unsigned long mod = sym->ctype.modifiers;
3013 if (mod & (MOD_STATIC | MOD_REGISTER))
3014 return;
3015 if (!(mod & MOD_TOPLEVEL))
3016 return;
3017 if (!Wdecl)
3018 return;
3019 if (sym->ident == &main_ident)
3020 return;
3021 warning(sym->pos, "symbol '%s' was not declared. Should it be static?", show_ident(sym->ident));
3022 }
3023 }
3024
3025 static struct symbol *evaluate_symbol(struct symbol *sym)
3026 {
3027 struct symbol *base_type;
3028
3029 if (!sym)
3030 return sym;
3031 if (sym->evaluated)
3032 return sym;
3033 sym->evaluated = 1;
3034
3035 sym = examine_symbol_type(sym);
3036 base_type = get_base_type(sym);
3037 if (!base_type)
3038 return NULL;
3039
3040 /* Evaluate the initializers */
3041 if (sym->initializer)
3042 evaluate_initializer(sym, &sym->initializer);
3043
3044 /* And finally, evaluate the body of the symbol too */
3045 if (base_type->type == SYM_FN) {
3046 struct symbol *curr = current_fn;
3047
3048 current_fn = base_type;
3049
3050 examine_fn_arguments(base_type);
3051 if (!base_type->stmt && base_type->inline_stmt)
3052 uninline(sym);
3053 if (base_type->stmt)
3054 evaluate_statement(base_type->stmt);
3055
3056 current_fn = curr;
3057 }
3058
3059 return base_type;
3060 }
3061
3062 void evaluate_symbol_list(struct symbol_list *list)
3063 {
3064 struct symbol *sym;
3065
3066 FOR_EACH_PTR(list, sym) {
3067 evaluate_symbol(sym);
3068 check_duplicates(sym);
3069 } END_FOR_EACH_PTR(sym);
3070 }
3071
3072 static struct symbol *evaluate_return_expression(struct statement *stmt)
3073 {
3074 struct expression *expr = stmt->expression;
3075 struct symbol *fntype;
3076
3077 evaluate_expression(expr);
3078 fntype = current_fn->ctype.base_type;
3079 if (!fntype || fntype == &void_ctype) {
3080 if (expr && expr->ctype != &void_ctype)
3081 expression_error(expr, "return expression in %s function", fntype?"void":"typeless");
3082 if (expr && Wreturn_void)
3083 warning(stmt->pos, "returning void-valued expression");
3084 return NULL;
3085 }
3086
3087 if (!expr) {
3088 sparse_error(stmt->pos, "return with no return value");
3089 return NULL;
3090 }
3091 if (!expr->ctype)
3092 return NULL;
3093 compatible_assignment_types(expr, fntype, &stmt->expression, "return expression");
3094 return NULL;
3095 }
3096
3097 static void evaluate_if_statement(struct statement *stmt)
3098 {
3099 if (!stmt->if_conditional)
3100 return;
3101
3102 evaluate_conditional(stmt->if_conditional, 0);
3103 evaluate_statement(stmt->if_true);
3104 evaluate_statement(stmt->if_false);
3105 }
3106
3107 static void evaluate_iterator(struct statement *stmt)
3108 {
3109 evaluate_conditional(stmt->iterator_pre_condition, 1);
3110 evaluate_conditional(stmt->iterator_post_condition,1);
3111 evaluate_statement(stmt->iterator_pre_statement);
3112 evaluate_statement(stmt->iterator_statement);
3113 evaluate_statement(stmt->iterator_post_statement);
3114 }
3115
3116 static void verify_output_constraint(struct expression *expr, const char *constraint)
3117 {
3118 switch (*constraint) {
3119 case '=': /* Assignment */
3120 case '+': /* Update */
3121 break;
3122 default:
3123 expression_error(expr, "output constraint is not an assignment constraint (\"%s\")", constraint);
3124 }
3125 }
3126
3127 static void verify_input_constraint(struct expression *expr, const char *constraint)
3128 {
3129 switch (*constraint) {
3130 case '=': /* Assignment */
3131 case '+': /* Update */
3132 expression_error(expr, "input constraint with assignment (\"%s\")", constraint);
3133 }
3134 }
3135
3136 static void evaluate_asm_statement(struct statement *stmt)
3137 {
3138 struct expression *expr;
3139 int state;
3140
3141 expr = stmt->asm_string;
3142 if (!expr || expr->type != EXPR_STRING) {
3143 sparse_error(stmt->pos, "need constant string for inline asm");
3144 return;
3145 }
3146
3147 state = 0;
3148 FOR_EACH_PTR(stmt->asm_outputs, expr) {
3149 struct ident *ident;
3150
3151 switch (state) {
3152 case 0: /* Identifier */
3153 state = 1;
3154 ident = (struct ident *)expr;
3155 continue;
3156
3157 case 1: /* Constraint */
3158 state = 2;
3159 if (!expr || expr->type != EXPR_STRING) {
3160 sparse_error(expr ? expr->pos : stmt->pos, "asm output constraint is not a string");
3161 *THIS_ADDRESS(expr) = NULL;
3162 continue;
3163 }
3164 verify_output_constraint(expr, expr->string->data);
3165 continue;
3166
3167 case 2: /* Expression */
3168 state = 0;
3169 if (!evaluate_expression(expr))
3170 return;
3171 if (!lvalue_expression(expr))
3172 warning(expr->pos, "asm output is not an lvalue");
3173 evaluate_assign_to(expr, expr->ctype);
3174 continue;
3175 }
3176 } END_FOR_EACH_PTR(expr);
3177
3178 state = 0;
3179 FOR_EACH_PTR(stmt->asm_inputs, expr) {
3180 struct ident *ident;
3181
3182 switch (state) {
3183 case 0: /* Identifier */
3184 state = 1;
3185 ident = (struct ident *)expr;
3186 continue;
3187
3188 case 1: /* Constraint */
3189 state = 2;
3190 if (!expr || expr->type != EXPR_STRING) {
3191 sparse_error(expr ? expr->pos : stmt->pos, "asm input constraint is not a string");
3192 *THIS_ADDRESS(expr) = NULL;
3193 continue;
3194 }
3195 verify_input_constraint(expr, expr->string->data);
3196 continue;
3197
3198 case 2: /* Expression */
3199 state = 0;
3200 if (!evaluate_expression(expr))
3201 return;
3202 continue;
3203 }
3204 } END_FOR_EACH_PTR(expr);
3205
3206 FOR_EACH_PTR(stmt->asm_clobbers, expr) {
3207 if (!expr) {
3208 sparse_error(stmt->pos, "bad asm output");
3209 return;
3210 }
3211 if (expr->type == EXPR_STRING)
3212 continue;
3213 expression_error(expr, "asm clobber is not a string");
3214 } END_FOR_EACH_PTR(expr);
3215 }
3216
3217 static void evaluate_case_statement(struct statement *stmt)
3218 {
3219 evaluate_expression(stmt->case_expression);
3220 evaluate_expression(stmt->case_to);
3221 evaluate_statement(stmt->case_statement);
3222 }
3223
3224 static void check_case_type(struct expression *switch_expr,
3225 struct expression *case_expr,
3226 struct expression **enumcase)
3227 {
3228 struct symbol *switch_type, *case_type;
3229 int sclass, cclass;
3230
3231 if (!case_expr)
3232 return;
3233
3234 switch_type = switch_expr->ctype;
3235 case_type = evaluate_expression(case_expr);
3236
3237 if (!switch_type || !case_type)
3238 goto Bad;
3239 if (enumcase) {
3240 if (*enumcase)
3241 warn_for_different_enum_types(case_expr->pos, case_type, (*enumcase)->ctype);
3242 else if (is_enum_type(case_type))
3243 *enumcase = case_expr;
3244 }
3245
3246 sclass = classify_type(switch_type, &switch_type);
3247 cclass = classify_type(case_type, &case_type);
3248
3249 /* both should be arithmetic */
3250 if (!(sclass & cclass & TYPE_NUM))
3251 goto Bad;
3252
3253 /* neither should be floating */
3254 if ((sclass | cclass) & TYPE_FLOAT)
3255 goto Bad;
3256
3257 /* if neither is restricted, we are OK */
3258 if (!((sclass | cclass) & TYPE_RESTRICT))
3259 return;
3260
3261 if (!restricted_binop_type(SPECIAL_EQUAL, case_expr, switch_expr,
3262 cclass, sclass, case_type, switch_type)) {
3263 unrestrict(case_expr, cclass, &case_type);
3264 unrestrict(switch_expr, sclass, &switch_type);
3265 }
3266 return;
3267
3268 Bad:
3269 expression_error(case_expr, "incompatible types for 'case' statement");
3270 }
3271
3272 static void evaluate_switch_statement(struct statement *stmt)
3273 {
3274 struct symbol *sym;
3275 struct expression *enumcase = NULL;
3276 struct expression **enumcase_holder = &enumcase;
3277 struct expression *sel = stmt->switch_expression;
3278
3279 evaluate_expression(sel);
3280 evaluate_statement(stmt->switch_statement);
3281 if (!sel)
3282 return;
3283 if (sel->ctype && is_enum_type(sel->ctype))
3284 enumcase_holder = NULL; /* Only check cases against switch */
3285
3286 FOR_EACH_PTR(stmt->switch_case->symbol_list, sym) {
3287 struct statement *case_stmt = sym->stmt;
3288 check_case_type(sel, case_stmt->case_expression, enumcase_holder);
3289 check_case_type(sel, case_stmt->case_to, enumcase_holder);
3290 } END_FOR_EACH_PTR(sym);
3291 }
3292
3293 struct symbol *evaluate_statement(struct statement *stmt)
3294 {
3295 if (!stmt)
3296 return NULL;
3297
3298 switch (stmt->type) {
3299 case STMT_DECLARATION: {
3300 struct symbol *s;
3301 FOR_EACH_PTR(stmt->declaration, s) {
3302 evaluate_symbol(s);
3303 } END_FOR_EACH_PTR(s);
3304 return NULL;
3305 }
3306
3307 case STMT_RETURN:
3308 return evaluate_return_expression(stmt);
3309
3310 case STMT_EXPRESSION:
3311 if (!evaluate_expression(stmt->expression))
3312 return NULL;
3313 if (stmt->expression->ctype == &null_ctype)
3314 stmt->expression = cast_to(stmt->expression, &ptr_ctype);
3315 return degenerate(stmt->expression);
3316
3317 case STMT_COMPOUND: {
3318 struct statement *s;
3319 struct symbol *type = NULL;
3320
3321 /* Evaluate the return symbol in the compound statement */
3322 evaluate_symbol(stmt->ret);
3323
3324 /*
3325 * Then, evaluate each statement, making the type of the
3326 * compound statement be the type of the last statement
3327 */
3328 type = evaluate_statement(stmt->args);
3329 FOR_EACH_PTR(stmt->stmts, s) {
3330 type = evaluate_statement(s);
3331 } END_FOR_EACH_PTR(s);
3332 if (!type)
3333 type = &void_ctype;
3334 return type;
3335 }
3336 case STMT_IF:
3337 evaluate_if_statement(stmt);
3338 return NULL;
3339 case STMT_ITERATOR:
3340 evaluate_iterator(stmt);
3341 return NULL;
3342 case STMT_SWITCH:
3343 evaluate_switch_statement(stmt);
3344 return NULL;
3345 case STMT_CASE:
3346 evaluate_case_statement(stmt);
3347 return NULL;
3348 case STMT_LABEL:
3349 return evaluate_statement(stmt->label_statement);
3350 case STMT_GOTO:
3351 evaluate_expression(stmt->goto_expression);
3352 return NULL;
3353 case STMT_NONE:
3354 break;
3355 case STMT_ASM:
3356 evaluate_asm_statement(stmt);
3357 return NULL;
3358 case STMT_CONTEXT:
3359 evaluate_expression(stmt->expression);
3360 return NULL;
3361 case STMT_RANGE:
3362 evaluate_expression(stmt->range_expression);
3363 evaluate_expression(stmt->range_low);
3364 evaluate_expression(stmt->range_high);
3365 return NULL;
3366 }
3367 return NULL;
3368 }
Static analysis for C