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[smatch.git] / evaluate.c
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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 = bytes_to_bits(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 = bytes_to_bits(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_ALL))
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 enum {
317 TYPE_NUM = 1,
318 TYPE_BITFIELD = 2,
319 TYPE_RESTRICT = 4,
320 TYPE_FLOAT = 8,
321 TYPE_PTR = 16,
322 TYPE_COMPOUND = 32,
323 TYPE_FOULED = 64,
324 TYPE_FN = 128,
325 };
326
327 static inline int classify_type(struct symbol *type, struct symbol **base)
328 {
329 static int type_class[SYM_BAD + 1] = {
330 [SYM_PTR] = TYPE_PTR,
331 [SYM_FN] = TYPE_PTR | TYPE_FN,
332 [SYM_ARRAY] = TYPE_PTR | TYPE_COMPOUND,
333 [SYM_STRUCT] = TYPE_COMPOUND,
334 [SYM_UNION] = TYPE_COMPOUND,
335 [SYM_BITFIELD] = TYPE_NUM | TYPE_BITFIELD,
336 [SYM_RESTRICT] = TYPE_NUM | TYPE_RESTRICT,
337 [SYM_FOULED] = TYPE_NUM | TYPE_RESTRICT | TYPE_FOULED,
338 };
339 if (type->type == SYM_NODE)
340 type = type->ctype.base_type;
341 if (type->type == SYM_TYPEOF) {
342 type = evaluate_expression(type->initializer);
343 if (!type)
344 type = &bad_ctype;
345 else if (type->type == SYM_NODE)
346 type = type->ctype.base_type;
347 }
348 if (type->type == SYM_ENUM)
349 type = type->ctype.base_type;
350 *base = type;
351 if (type->type == SYM_BASETYPE) {
352 if (type->ctype.base_type == &int_type)
353 return TYPE_NUM;
354 if (type->ctype.base_type == &fp_type)
355 return TYPE_NUM | TYPE_FLOAT;
356 }
357 return type_class[type->type];
358 }
359
360 #define is_int(class) ((class & (TYPE_NUM | TYPE_FLOAT)) == TYPE_NUM)
361
362 static inline int is_string_type(struct symbol *type)
363 {
364 if (type->type == SYM_NODE)
365 type = type->ctype.base_type;
366 return type->type == SYM_ARRAY && is_byte_type(type->ctype.base_type);
367 }
368
369 static struct symbol *bad_expr_type(struct expression *expr)
370 {
371 sparse_error(expr->pos, "incompatible types for operation (%s)", show_special(expr->op));
372 switch (expr->type) {
373 case EXPR_BINOP:
374 case EXPR_COMPARE:
375 info(expr->pos, " left side has type %s", show_typename(expr->left->ctype));
376 info(expr->pos, " right side has type %s", show_typename(expr->right->ctype));
377 break;
378 case EXPR_PREOP:
379 case EXPR_POSTOP:
380 info(expr->pos, " argument has type %s", show_typename(expr->unop->ctype));
381 break;
382 default:
383 break;
384 }
385
386 expr->flags = 0;
387 return expr->ctype = &bad_ctype;
388 }
389
390 static int restricted_value(struct expression *v, struct symbol *type)
391 {
392 if (v->type != EXPR_VALUE)
393 return 1;
394 if (v->value != 0)
395 return 1;
396 return 0;
397 }
398
399 static int restricted_binop(int op, struct symbol *type)
400 {
401 switch (op) {
402 case '&':
403 case '=':
404 case SPECIAL_AND_ASSIGN:
405 case SPECIAL_OR_ASSIGN:
406 case SPECIAL_XOR_ASSIGN:
407 return 1; /* unfoul */
408 case '|':
409 case '^':
410 case '?':
411 return 2; /* keep fouled */
412 case SPECIAL_EQUAL:
413 case SPECIAL_NOTEQUAL:
414 return 3; /* warn if fouled */
415 default:
416 return 0; /* warn */
417 }
418 }
419
420 static int restricted_unop(int op, struct symbol **type)
421 {
422 if (op == '~') {
423 if ((*type)->bit_size < bits_in_int)
424 *type = befoul(*type);
425 return 0;
426 } if (op == '+')
427 return 0;
428 return 1;
429 }
430
431 /* type should be SYM_FOULED */
432 static inline struct symbol *unfoul(struct symbol *type)
433 {
434 return type->ctype.base_type;
435 }
436
437 static struct symbol *restricted_binop_type(int op,
438 struct expression *left,
439 struct expression *right,
440 int lclass, int rclass,
441 struct symbol *ltype,
442 struct symbol *rtype)
443 {
444 struct symbol *ctype = NULL;
445 if (lclass & TYPE_RESTRICT) {
446 if (rclass & TYPE_RESTRICT) {
447 if (ltype == rtype) {
448 ctype = ltype;
449 } else if (lclass & TYPE_FOULED) {
450 if (unfoul(ltype) == rtype)
451 ctype = ltype;
452 } else if (rclass & TYPE_FOULED) {
453 if (unfoul(rtype) == ltype)
454 ctype = rtype;
455 }
456 } else {
457 if (!restricted_value(right, ltype))
458 ctype = ltype;
459 }
460 } else if (!restricted_value(left, rtype))
461 ctype = rtype;
462
463 if (ctype) {
464 switch (restricted_binop(op, ctype)) {
465 case 1:
466 if ((lclass ^ rclass) & TYPE_FOULED)
467 ctype = unfoul(ctype);
468 break;
469 case 3:
470 if (!(lclass & rclass & TYPE_FOULED))
471 break;
472 case 0:
473 ctype = NULL;
474 default:
475 break;
476 }
477 }
478
479 return ctype;
480 }
481
482 static inline void unrestrict(struct expression *expr,
483 int class, struct symbol **ctype)
484 {
485 if (class & TYPE_RESTRICT) {
486 if (class & TYPE_FOULED)
487 *ctype = unfoul(*ctype);
488 warning(expr->pos, "%s degrades to integer",
489 show_typename(*ctype));
490 *ctype = (*ctype)->ctype.base_type; /* get to arithmetic type */
491 }
492 }
493
494 static struct symbol *usual_conversions(int op,
495 struct expression *left,
496 struct expression *right,
497 int lclass, int rclass,
498 struct symbol *ltype,
499 struct symbol *rtype)
500 {
501 struct symbol *ctype;
502
503 warn_for_different_enum_types(right->pos, left->ctype, right->ctype);
504
505 if ((lclass | rclass) & TYPE_RESTRICT)
506 goto Restr;
507
508 Normal:
509 if (!(lclass & TYPE_FLOAT)) {
510 if (!(rclass & TYPE_FLOAT))
511 return bigger_int_type(ltype, rtype);
512 else
513 return rtype;
514 } else if (rclass & TYPE_FLOAT) {
515 unsigned long lmod = ltype->ctype.modifiers;
516 unsigned long rmod = rtype->ctype.modifiers;
517 if (rmod & ~lmod & (MOD_LONG_ALL))
518 return rtype;
519 else
520 return ltype;
521 } else
522 return ltype;
523
524 Restr:
525 ctype = restricted_binop_type(op, left, right,
526 lclass, rclass, ltype, rtype);
527 if (ctype)
528 return ctype;
529
530 unrestrict(left, lclass, &ltype);
531 unrestrict(right, rclass, &rtype);
532
533 goto Normal;
534 }
535
536 static inline int lvalue_expression(struct expression *expr)
537 {
538 return expr->type == EXPR_PREOP && expr->op == '*';
539 }
540
541 static struct symbol *evaluate_ptr_add(struct expression *expr, struct symbol *itype)
542 {
543 struct expression *index = expr->right;
544 struct symbol *ctype, *base;
545 int multiply;
546
547 classify_type(degenerate(expr->left), &ctype);
548 base = examine_pointer_target(ctype);
549
550 if (!base) {
551 expression_error(expr, "missing type information");
552 return NULL;
553 }
554 if (is_function(base)) {
555 expression_error(expr, "arithmetics on pointers to functions");
556 return NULL;
557 }
558
559 /* Get the size of whatever the pointer points to */
560 multiply = is_void_type(base) ? 1 : bits_to_bytes(base->bit_size);
561
562 if (ctype == &null_ctype)
563 ctype = &ptr_ctype;
564 expr->ctype = ctype;
565
566 if (multiply == 1 && itype->bit_size >= bits_in_pointer)
567 return ctype;
568
569 if (index->type == EXPR_VALUE) {
570 struct expression *val = alloc_expression(expr->pos, EXPR_VALUE);
571 unsigned long long v = index->value, mask;
572 mask = 1ULL << (itype->bit_size - 1);
573 if (v & mask)
574 v |= -mask;
575 else
576 v &= mask - 1;
577 v *= multiply;
578 mask = 1ULL << (bits_in_pointer - 1);
579 v &= mask | (mask - 1);
580 val->value = v;
581 val->ctype = ssize_t_ctype;
582 expr->right = val;
583 return ctype;
584 }
585
586 if (itype->bit_size < bits_in_pointer)
587 index = cast_to(index, ssize_t_ctype);
588
589 if (multiply > 1) {
590 struct expression *val = alloc_expression(expr->pos, EXPR_VALUE);
591 struct expression *mul = alloc_expression(expr->pos, EXPR_BINOP);
592
593 val->ctype = ssize_t_ctype;
594 val->value = multiply;
595
596 mul->op = '*';
597 mul->ctype = ssize_t_ctype;
598 mul->left = index;
599 mul->right = val;
600 index = mul;
601 }
602
603 expr->right = index;
604 return ctype;
605 }
606
607 static void examine_fn_arguments(struct symbol *fn);
608
609 #define MOD_IGN (MOD_VOLATILE | MOD_CONST)
610
611 const char *type_difference(struct ctype *c1, struct ctype *c2,
612 unsigned long mod1, unsigned long mod2)
613 {
614 unsigned long as1 = c1->as, as2 = c2->as;
615 struct symbol *t1 = c1->base_type;
616 struct symbol *t2 = c2->base_type;
617 int move1 = 1, move2 = 1;
618 mod1 |= c1->modifiers;
619 mod2 |= c2->modifiers;
620 for (;;) {
621 unsigned long diff;
622 int type;
623 struct symbol *base1 = t1->ctype.base_type;
624 struct symbol *base2 = t2->ctype.base_type;
625
626 /*
627 * FIXME! Collect alignment and context too here!
628 */
629 if (move1) {
630 if (t1 && t1->type != SYM_PTR) {
631 mod1 |= t1->ctype.modifiers;
632 as1 |= t1->ctype.as;
633 }
634 move1 = 0;
635 }
636
637 if (move2) {
638 if (t2 && t2->type != SYM_PTR) {
639 mod2 |= t2->ctype.modifiers;
640 as2 |= t2->ctype.as;
641 }
642 move2 = 0;
643 }
644
645 if (t1 == t2)
646 break;
647 if (!t1 || !t2)
648 return "different types";
649
650 if (t1->type == SYM_NODE || t1->type == SYM_ENUM) {
651 t1 = base1;
652 move1 = 1;
653 if (!t1)
654 return "bad types";
655 continue;
656 }
657
658 if (t2->type == SYM_NODE || t2->type == SYM_ENUM) {
659 t2 = base2;
660 move2 = 1;
661 if (!t2)
662 return "bad types";
663 continue;
664 }
665
666 move1 = move2 = 1;
667 type = t1->type;
668 if (type != t2->type)
669 return "different base types";
670
671 switch (type) {
672 default:
673 sparse_error(t1->pos,
674 "internal error: bad type in derived(%d)",
675 type);
676 return "bad types";
677 case SYM_RESTRICT:
678 return "different base types";
679 case SYM_UNION:
680 case SYM_STRUCT:
681 /* allow definition of incomplete structs and unions */
682 if (t1->ident == t2->ident)
683 return NULL;
684 return "different base types";
685 case SYM_ARRAY:
686 /* XXX: we ought to compare sizes */
687 break;
688 case SYM_PTR:
689 if (as1 != as2)
690 return "different address spaces";
691 /* MOD_SPECIFIER is due to idiocy in parse.c */
692 if ((mod1 ^ mod2) & ~MOD_IGNORE & ~MOD_SPECIFIER)
693 return "different modifiers";
694 /* we could be lazier here */
695 base1 = examine_pointer_target(t1);
696 base2 = examine_pointer_target(t2);
697 mod1 = t1->ctype.modifiers;
698 as1 = t1->ctype.as;
699 mod2 = t2->ctype.modifiers;
700 as2 = t2->ctype.as;
701 break;
702 case SYM_FN: {
703 struct symbol *arg1, *arg2;
704 int i;
705
706 if (as1 != as2)
707 return "different address spaces";
708 if ((mod1 ^ mod2) & ~MOD_IGNORE & ~MOD_SIGNEDNESS)
709 return "different modifiers";
710 mod1 = t1->ctype.modifiers;
711 as1 = t1->ctype.as;
712 mod2 = t2->ctype.modifiers;
713 as2 = t2->ctype.as;
714
715 if (base1->variadic != base2->variadic)
716 return "incompatible variadic arguments";
717 examine_fn_arguments(t1);
718 examine_fn_arguments(t2);
719 PREPARE_PTR_LIST(t1->arguments, arg1);
720 PREPARE_PTR_LIST(t2->arguments, arg2);
721 i = 1;
722 for (;;) {
723 const char *diffstr;
724 if (!arg1 && !arg2)
725 break;
726 if (!arg1 || !arg2)
727 return "different argument counts";
728 diffstr = type_difference(&arg1->ctype,
729 &arg2->ctype,
730 MOD_IGN, MOD_IGN);
731 if (diffstr) {
732 static char argdiff[80];
733 sprintf(argdiff, "incompatible argument %d (%s)", i, diffstr);
734 return argdiff;
735 }
736 NEXT_PTR_LIST(arg1);
737 NEXT_PTR_LIST(arg2);
738 i++;
739 }
740 FINISH_PTR_LIST(arg2);
741 FINISH_PTR_LIST(arg1);
742 break;
743 }
744 case SYM_BASETYPE:
745 if (as1 != as2)
746 return "different address spaces";
747 if (base1 != base2)
748 return "different base types";
749 diff = (mod1 ^ mod2) & ~MOD_IGNORE;
750 if (!diff)
751 return NULL;
752 if (diff & MOD_SIZE)
753 return "different type sizes";
754 else if (diff & ~MOD_SIGNEDNESS)
755 return "different modifiers";
756 else
757 return "different signedness";
758 }
759 t1 = base1;
760 t2 = base2;
761 }
762 if (as1 != as2)
763 return "different address spaces";
764 if ((mod1 ^ mod2) & ~MOD_IGNORE & ~MOD_SIGNEDNESS)
765 return "different modifiers";
766 return NULL;
767 }
768
769 static void bad_null(struct expression *expr)
770 {
771 if (Wnon_pointer_null)
772 warning(expr->pos, "Using plain integer as NULL pointer");
773 }
774
775 static unsigned long target_qualifiers(struct symbol *type)
776 {
777 unsigned long mod = type->ctype.modifiers & MOD_IGN;
778 if (type->ctype.base_type && type->ctype.base_type->type == SYM_ARRAY)
779 mod = 0;
780 return mod;
781 }
782
783 static struct symbol *evaluate_ptr_sub(struct expression *expr)
784 {
785 const char *typediff;
786 struct symbol *ltype, *rtype;
787 struct expression *l = expr->left;
788 struct expression *r = expr->right;
789 struct symbol *lbase;
790
791 classify_type(degenerate(l), &ltype);
792 classify_type(degenerate(r), &rtype);
793
794 lbase = examine_pointer_target(ltype);
795 examine_pointer_target(rtype);
796 typediff = type_difference(&ltype->ctype, &rtype->ctype,
797 target_qualifiers(rtype),
798 target_qualifiers(ltype));
799 if (typediff)
800 expression_error(expr, "subtraction of different types can't work (%s)", typediff);
801
802 if (is_function(lbase)) {
803 expression_error(expr, "subtraction of functions? Share your drugs");
804 return NULL;
805 }
806
807 expr->ctype = ssize_t_ctype;
808 if (lbase->bit_size > bits_in_char) {
809 struct expression *sub = alloc_expression(expr->pos, EXPR_BINOP);
810 struct expression *div = expr;
811 struct expression *val = alloc_expression(expr->pos, EXPR_VALUE);
812 unsigned long value = bits_to_bytes(lbase->bit_size);
813
814 val->ctype = size_t_ctype;
815 val->value = value;
816
817 if (value & (value-1)) {
818 if (Wptr_subtraction_blows)
819 warning(expr->pos, "potentially expensive pointer subtraction");
820 }
821
822 sub->op = '-';
823 sub->ctype = ssize_t_ctype;
824 sub->left = l;
825 sub->right = r;
826
827 div->op = '/';
828 div->left = sub;
829 div->right = val;
830 }
831
832 return ssize_t_ctype;
833 }
834
835 #define is_safe_type(type) ((type)->ctype.modifiers & MOD_SAFE)
836
837 static struct symbol *evaluate_conditional(struct expression *expr, int iterator)
838 {
839 struct symbol *ctype;
840
841 if (!expr)
842 return NULL;
843
844 if (!iterator && expr->type == EXPR_ASSIGNMENT && expr->op == '=')
845 warning(expr->pos, "assignment expression in conditional");
846
847 ctype = evaluate_expression(expr);
848 if (ctype) {
849 if (is_safe_type(ctype))
850 warning(expr->pos, "testing a 'safe expression'");
851 }
852
853 return ctype;
854 }
855
856 static struct symbol *evaluate_logical(struct expression *expr)
857 {
858 if (!evaluate_conditional(expr->left, 0))
859 return NULL;
860 if (!evaluate_conditional(expr->right, 0))
861 return NULL;
862
863 expr->ctype = &bool_ctype;
864 if (expr->flags) {
865 if (!(expr->left->flags & expr->right->flags & Int_const_expr))
866 expr->flags = 0;
867 }
868 return &bool_ctype;
869 }
870
871 static struct symbol *evaluate_binop(struct expression *expr)
872 {
873 struct symbol *ltype, *rtype, *ctype;
874 int lclass = classify_type(expr->left->ctype, &ltype);
875 int rclass = classify_type(expr->right->ctype, &rtype);
876 int op = expr->op;
877
878 if (expr->flags) {
879 if (!(expr->left->flags & expr->right->flags & Int_const_expr))
880 expr->flags = 0;
881 }
882
883 /* number op number */
884 if (lclass & rclass & TYPE_NUM) {
885 if ((lclass | rclass) & TYPE_FLOAT) {
886 switch (op) {
887 case '+': case '-': case '*': case '/':
888 break;
889 default:
890 return bad_expr_type(expr);
891 }
892 }
893
894 if (op == SPECIAL_LEFTSHIFT || op == SPECIAL_RIGHTSHIFT) {
895 // shifts do integer promotions, but that's it.
896 unrestrict(expr->left, lclass, &ltype);
897 unrestrict(expr->right, rclass, &rtype);
898 ctype = ltype = integer_promotion(ltype);
899 rtype = integer_promotion(rtype);
900 } else {
901 // The rest do usual conversions
902 const unsigned left_not = expr->left->type == EXPR_PREOP
903 && expr->left->op == '!';
904 const unsigned right_not = expr->right->type == EXPR_PREOP
905 && expr->right->op == '!';
906 if ((op == '&' || op == '|') && (left_not || right_not))
907 warning(expr->pos, "dubious: %sx %c %sy",
908 left_not ? "!" : "",
909 op,
910 right_not ? "!" : "");
911
912 ltype = usual_conversions(op, expr->left, expr->right,
913 lclass, rclass, ltype, rtype);
914 ctype = rtype = ltype;
915 }
916
917 expr->left = cast_to(expr->left, ltype);
918 expr->right = cast_to(expr->right, rtype);
919 expr->ctype = ctype;
920 return ctype;
921 }
922
923 /* pointer (+|-) integer */
924 if (lclass & TYPE_PTR && is_int(rclass) && (op == '+' || op == '-')) {
925 unrestrict(expr->right, rclass, &rtype);
926 return evaluate_ptr_add(expr, rtype);
927 }
928
929 /* integer + pointer */
930 if (rclass & TYPE_PTR && is_int(lclass) && op == '+') {
931 struct expression *index = expr->left;
932 unrestrict(index, lclass, &ltype);
933 expr->left = expr->right;
934 expr->right = index;
935 return evaluate_ptr_add(expr, ltype);
936 }
937
938 /* pointer - pointer */
939 if (lclass & rclass & TYPE_PTR && expr->op == '-')
940 return evaluate_ptr_sub(expr);
941
942 return bad_expr_type(expr);
943 }
944
945 static struct symbol *evaluate_comma(struct expression *expr)
946 {
947 expr->ctype = degenerate(expr->right);
948 if (expr->ctype == &null_ctype)
949 expr->ctype = &ptr_ctype;
950 expr->flags &= expr->left->flags & expr->right->flags;
951 return expr->ctype;
952 }
953
954 static int modify_for_unsigned(int op)
955 {
956 if (op == '<')
957 op = SPECIAL_UNSIGNED_LT;
958 else if (op == '>')
959 op = SPECIAL_UNSIGNED_GT;
960 else if (op == SPECIAL_LTE)
961 op = SPECIAL_UNSIGNED_LTE;
962 else if (op == SPECIAL_GTE)
963 op = SPECIAL_UNSIGNED_GTE;
964 return op;
965 }
966
967 static inline int is_null_pointer_constant(struct expression *e)
968 {
969 if (e->ctype == &null_ctype)
970 return 1;
971 if (!(e->flags & Int_const_expr))
972 return 0;
973 return is_zero_constant(e) ? 2 : 0;
974 }
975
976 static struct symbol *evaluate_compare(struct expression *expr)
977 {
978 struct expression *left = expr->left, *right = expr->right;
979 struct symbol *ltype, *rtype, *lbase, *rbase;
980 int lclass = classify_type(degenerate(left), &ltype);
981 int rclass = classify_type(degenerate(right), &rtype);
982 struct symbol *ctype;
983 const char *typediff;
984
985 if (expr->flags) {
986 if (!(expr->left->flags & expr->right->flags & Int_const_expr))
987 expr->flags = 0;
988 }
989
990 /* Type types? */
991 if (is_type_type(ltype) && is_type_type(rtype))
992 goto OK;
993
994 if (is_safe_type(left->ctype) || is_safe_type(right->ctype))
995 warning(expr->pos, "testing a 'safe expression'");
996
997 /* number on number */
998 if (lclass & rclass & TYPE_NUM) {
999 ctype = usual_conversions(expr->op, expr->left, expr->right,
1000 lclass, rclass, ltype, rtype);
1001 expr->left = cast_to(expr->left, ctype);
1002 expr->right = cast_to(expr->right, ctype);
1003 if (ctype->ctype.modifiers & MOD_UNSIGNED)
1004 expr->op = modify_for_unsigned(expr->op);
1005 goto OK;
1006 }
1007
1008 /* at least one must be a pointer */
1009 if (!((lclass | rclass) & TYPE_PTR))
1010 return bad_expr_type(expr);
1011
1012 /* equality comparisons can be with null pointer constants */
1013 if (expr->op == SPECIAL_EQUAL || expr->op == SPECIAL_NOTEQUAL) {
1014 int is_null1 = is_null_pointer_constant(left);
1015 int is_null2 = is_null_pointer_constant(right);
1016 if (is_null1 == 2)
1017 bad_null(left);
1018 if (is_null2 == 2)
1019 bad_null(right);
1020 if (is_null1 && is_null2) {
1021 int positive = expr->op == SPECIAL_EQUAL;
1022 expr->type = EXPR_VALUE;
1023 expr->value = positive;
1024 goto OK;
1025 }
1026 if (is_null1 && (rclass & TYPE_PTR)) {
1027 left = cast_to(left, rtype);
1028 goto OK;
1029 }
1030 if (is_null2 && (lclass & TYPE_PTR)) {
1031 right = cast_to(right, ltype);
1032 goto OK;
1033 }
1034 }
1035 /* both should be pointers */
1036 if (!(lclass & rclass & TYPE_PTR))
1037 return bad_expr_type(expr);
1038 expr->op = modify_for_unsigned(expr->op);
1039
1040 lbase = examine_pointer_target(ltype);
1041 rbase = examine_pointer_target(rtype);
1042
1043 /* they also have special treatment for pointers to void */
1044 if (expr->op == SPECIAL_EQUAL || expr->op == SPECIAL_NOTEQUAL) {
1045 if (ltype->ctype.as == rtype->ctype.as) {
1046 if (lbase == &void_ctype) {
1047 right = cast_to(right, ltype);
1048 goto OK;
1049 }
1050 if (rbase == &void_ctype) {
1051 left = cast_to(left, rtype);
1052 goto OK;
1053 }
1054 }
1055 }
1056
1057 typediff = type_difference(&ltype->ctype, &rtype->ctype,
1058 target_qualifiers(rtype),
1059 target_qualifiers(ltype));
1060 if (!typediff)
1061 goto OK;
1062
1063 expression_error(expr, "incompatible types in comparison expression (%s)", typediff);
1064 return NULL;
1065
1066 OK:
1067 expr->ctype = &bool_ctype;
1068 return &bool_ctype;
1069 }
1070
1071 /*
1072 * NOTE! The degenerate case of "x ? : y", where we don't
1073 * have a true case, this will possibly promote "x" to the
1074 * same type as "y", and thus _change_ the conditional
1075 * test in the expression. But since promotion is "safe"
1076 * for testing, that's OK.
1077 */
1078 static struct symbol *evaluate_conditional_expression(struct expression *expr)
1079 {
1080 struct expression **true;
1081 struct symbol *ctype, *ltype, *rtype, *lbase, *rbase;
1082 int lclass, rclass;
1083 const char * typediff;
1084 int qual;
1085
1086 if (!evaluate_conditional(expr->conditional, 0))
1087 return NULL;
1088 if (!evaluate_expression(expr->cond_false))
1089 return NULL;
1090
1091 ctype = degenerate(expr->conditional);
1092 rtype = degenerate(expr->cond_false);
1093
1094 true = &expr->conditional;
1095 ltype = ctype;
1096 if (expr->cond_true) {
1097 if (!evaluate_expression(expr->cond_true))
1098 return NULL;
1099 ltype = degenerate(expr->cond_true);
1100 true = &expr->cond_true;
1101 }
1102
1103 if (expr->flags) {
1104 int flags = expr->conditional->flags & Int_const_expr;
1105 flags &= (*true)->flags & expr->cond_false->flags;
1106 if (!flags)
1107 expr->flags = 0;
1108 }
1109
1110 lclass = classify_type(ltype, &ltype);
1111 rclass = classify_type(rtype, &rtype);
1112 if (lclass & rclass & TYPE_NUM) {
1113 ctype = usual_conversions('?', *true, expr->cond_false,
1114 lclass, rclass, ltype, rtype);
1115 *true = cast_to(*true, ctype);
1116 expr->cond_false = cast_to(expr->cond_false, ctype);
1117 goto out;
1118 }
1119
1120 if ((lclass | rclass) & TYPE_PTR) {
1121 int is_null1 = is_null_pointer_constant(*true);
1122 int is_null2 = is_null_pointer_constant(expr->cond_false);
1123
1124 if (is_null1 && is_null2) {
1125 *true = cast_to(*true, &ptr_ctype);
1126 expr->cond_false = cast_to(expr->cond_false, &ptr_ctype);
1127 ctype = &ptr_ctype;
1128 goto out;
1129 }
1130 if (is_null1 && (rclass & TYPE_PTR)) {
1131 if (is_null1 == 2)
1132 bad_null(*true);
1133 *true = cast_to(*true, rtype);
1134 ctype = rtype;
1135 goto out;
1136 }
1137 if (is_null2 && (lclass & TYPE_PTR)) {
1138 if (is_null2 == 2)
1139 bad_null(expr->cond_false);
1140 expr->cond_false = cast_to(expr->cond_false, ltype);
1141 ctype = ltype;
1142 goto out;
1143 }
1144 if (!(lclass & rclass & TYPE_PTR)) {
1145 typediff = "different types";
1146 goto Err;
1147 }
1148 /* OK, it's pointer on pointer */
1149 if (ltype->ctype.as != rtype->ctype.as) {
1150 typediff = "different address spaces";
1151 goto Err;
1152 }
1153
1154 /* need to be lazier here */
1155 lbase = examine_pointer_target(ltype);
1156 rbase = examine_pointer_target(rtype);
1157 qual = target_qualifiers(ltype) | target_qualifiers(rtype);
1158
1159 if (lbase == &void_ctype) {
1160 /* XXX: pointers to function should warn here */
1161 ctype = ltype;
1162 goto Qual;
1163
1164 }
1165 if (rbase == &void_ctype) {
1166 /* XXX: pointers to function should warn here */
1167 ctype = rtype;
1168 goto Qual;
1169 }
1170 /* XXX: that should be pointer to composite */
1171 ctype = ltype;
1172 typediff = type_difference(&ltype->ctype, &rtype->ctype,
1173 qual, qual);
1174 if (!typediff)
1175 goto Qual;
1176 goto Err;
1177 }
1178
1179 /* void on void, struct on same struct, union on same union */
1180 if (ltype == rtype) {
1181 ctype = ltype;
1182 goto out;
1183 }
1184 typediff = "different base types";
1185
1186 Err:
1187 expression_error(expr, "incompatible types in conditional expression (%s)", typediff);
1188 return NULL;
1189
1190 out:
1191 expr->ctype = ctype;
1192 return ctype;
1193
1194 Qual:
1195 if (qual & ~ctype->ctype.modifiers) {
1196 struct symbol *sym = alloc_symbol(ctype->pos, SYM_PTR);
1197 *sym = *ctype;
1198 sym->ctype.modifiers |= qual;
1199 ctype = sym;
1200 }
1201 *true = cast_to(*true, ctype);
1202 expr->cond_false = cast_to(expr->cond_false, ctype);
1203 goto out;
1204 }
1205
1206 /* FP assignments can not do modulo or bit operations */
1207 static int compatible_float_op(int op)
1208 {
1209 return op == SPECIAL_ADD_ASSIGN ||
1210 op == SPECIAL_SUB_ASSIGN ||
1211 op == SPECIAL_MUL_ASSIGN ||
1212 op == SPECIAL_DIV_ASSIGN;
1213 }
1214
1215 static int evaluate_assign_op(struct expression *expr)
1216 {
1217 struct symbol *target = expr->left->ctype;
1218 struct symbol *source = expr->right->ctype;
1219 struct symbol *t, *s;
1220 int tclass = classify_type(target, &t);
1221 int sclass = classify_type(source, &s);
1222 int op = expr->op;
1223
1224 if (tclass & sclass & TYPE_NUM) {
1225 if (tclass & TYPE_FLOAT && !compatible_float_op(op)) {
1226 expression_error(expr, "invalid assignment");
1227 return 0;
1228 }
1229 if (tclass & TYPE_RESTRICT) {
1230 if (!restricted_binop(op, t)) {
1231 warning(expr->pos, "bad assignment (%s) to %s",
1232 show_special(op), show_typename(t));
1233 expr->right = cast_to(expr->right, target);
1234 return 0;
1235 }
1236 /* allowed assignments unfoul */
1237 if (sclass & TYPE_FOULED && unfoul(s) == t)
1238 goto Cast;
1239 if (!restricted_value(expr->right, t))
1240 return 1;
1241 } else if (!(sclass & TYPE_RESTRICT))
1242 goto Cast;
1243 /* source and target would better be identical restricted */
1244 if (t == s)
1245 return 1;
1246 warning(expr->pos, "invalid assignment: %s", show_special(op));
1247 info(expr->pos, " left side has type %s", show_typename(t));
1248 info(expr->pos, " right side has type %s", show_typename(s));
1249 expr->right = cast_to(expr->right, target);
1250 return 0;
1251 }
1252 if (tclass == TYPE_PTR && is_int(sclass)) {
1253 if (op == SPECIAL_ADD_ASSIGN || op == SPECIAL_SUB_ASSIGN) {
1254 unrestrict(expr->right, sclass, &s);
1255 evaluate_ptr_add(expr, s);
1256 return 1;
1257 }
1258 expression_error(expr, "invalid pointer assignment");
1259 return 0;
1260 }
1261
1262 expression_error(expr, "invalid assignment");
1263 return 0;
1264
1265 Cast:
1266 expr->right = cast_to(expr->right, target);
1267 return 1;
1268 }
1269
1270 static int whitelist_pointers(struct symbol *t1, struct symbol *t2)
1271 {
1272 if (t1 == t2)
1273 return 0; /* yes, 0 - we don't want a cast_to here */
1274 if (t1 == &void_ctype)
1275 return 1;
1276 if (t2 == &void_ctype)
1277 return 1;
1278 if (classify_type(t1, &t1) != TYPE_NUM)
1279 return 0;
1280 if (classify_type(t2, &t2) != TYPE_NUM)
1281 return 0;
1282 if (t1 == t2)
1283 return 1;
1284 if (t1->ctype.modifiers & t2->ctype.modifiers & MOD_CHAR)
1285 return 1;
1286 if ((t1->ctype.modifiers ^ t2->ctype.modifiers) & MOD_SIZE)
1287 return 0;
1288 return !Wtypesign;
1289 }
1290
1291 static int compatible_assignment_types(struct expression *expr, struct symbol *target,
1292 struct expression **rp, const char *where)
1293 {
1294 const char *typediff;
1295 struct symbol *source = degenerate(*rp);
1296 struct symbol *t, *s;
1297 int tclass = classify_type(target, &t);
1298 int sclass = classify_type(source, &s);
1299
1300 if (tclass & sclass & TYPE_NUM) {
1301 if (tclass & TYPE_RESTRICT) {
1302 /* allowed assignments unfoul */
1303 if (sclass & TYPE_FOULED && unfoul(s) == t)
1304 goto Cast;
1305 if (!restricted_value(*rp, target))
1306 return 1;
1307 if (s == t)
1308 return 1;
1309 } else if (!(sclass & TYPE_RESTRICT))
1310 goto Cast;
1311 typediff = "different base types";
1312 goto Err;
1313 }
1314
1315 if (tclass == TYPE_PTR) {
1316 unsigned long mod1, mod2;
1317 struct symbol *b1, *b2;
1318 // NULL pointer is always OK
1319 int is_null = is_null_pointer_constant(*rp);
1320 if (is_null) {
1321 if (is_null == 2)
1322 bad_null(*rp);
1323 goto Cast;
1324 }
1325 if (!(sclass & TYPE_PTR)) {
1326 typediff = "different base types";
1327 goto Err;
1328 }
1329 b1 = examine_pointer_target(t);
1330 b2 = examine_pointer_target(s);
1331 mod1 = target_qualifiers(t);
1332 mod2 = target_qualifiers(s);
1333 if (whitelist_pointers(b1, b2)) {
1334 /*
1335 * assignments to/from void * are OK, provided that
1336 * we do not remove qualifiers from pointed to [C]
1337 * or mix address spaces [sparse].
1338 */
1339 if (t->ctype.as != s->ctype.as) {
1340 typediff = "different address spaces";
1341 goto Err;
1342 }
1343 if (mod2 & ~mod1) {
1344 typediff = "different modifiers";
1345 goto Err;
1346 }
1347 goto Cast;
1348 }
1349 /* It's OK if the target is more volatile or const than the source */
1350 typediff = type_difference(&t->ctype, &s->ctype, 0, mod1);
1351 if (typediff)
1352 goto Err;
1353 return 1;
1354 }
1355
1356 if ((tclass & TYPE_COMPOUND) && s == t)
1357 return 1;
1358
1359 if (tclass & TYPE_NUM) {
1360 /* XXX: need to turn into comparison with NULL */
1361 if (t == &bool_ctype && (sclass & TYPE_PTR))
1362 goto Cast;
1363 typediff = "different base types";
1364 goto Err;
1365 }
1366 typediff = "invalid types";
1367
1368 Err:
1369 warning(expr->pos, "incorrect type in %s (%s)", where, typediff);
1370 info(expr->pos, " expected %s", show_typename(target));
1371 info(expr->pos, " got %s", show_typename(source));
1372 *rp = cast_to(*rp, target);
1373 return 0;
1374 Cast:
1375 *rp = cast_to(*rp, target);
1376 return 1;
1377 }
1378
1379 static void mark_assigned(struct expression *expr)
1380 {
1381 struct symbol *sym;
1382
1383 if (!expr)
1384 return;
1385 switch (expr->type) {
1386 case EXPR_SYMBOL:
1387 sym = expr->symbol;
1388 if (!sym)
1389 return;
1390 if (sym->type != SYM_NODE)
1391 return;
1392 sym->ctype.modifiers |= MOD_ASSIGNED;
1393 return;
1394
1395 case EXPR_BINOP:
1396 mark_assigned(expr->left);
1397 mark_assigned(expr->right);
1398 return;
1399 case EXPR_CAST:
1400 case EXPR_FORCE_CAST:
1401 mark_assigned(expr->cast_expression);
1402 return;
1403 case EXPR_SLICE:
1404 mark_assigned(expr->base);
1405 return;
1406 default:
1407 /* Hmm? */
1408 return;
1409 }
1410 }
1411
1412 static void evaluate_assign_to(struct expression *left, struct symbol *type)
1413 {
1414 if (type->ctype.modifiers & MOD_CONST)
1415 expression_error(left, "assignment to const expression");
1416
1417 /* We know left is an lvalue, so it's a "preop-*" */
1418 mark_assigned(left->unop);
1419 }
1420
1421 static struct symbol *evaluate_assignment(struct expression *expr)
1422 {
1423 struct expression *left = expr->left;
1424 struct expression *where = expr;
1425 struct symbol *ltype;
1426
1427 if (!lvalue_expression(left)) {
1428 expression_error(expr, "not an lvalue");
1429 return NULL;
1430 }
1431
1432 ltype = left->ctype;
1433
1434 if (expr->op != '=') {
1435 if (!evaluate_assign_op(expr))
1436 return NULL;
1437 } else {
1438 if (!compatible_assignment_types(where, ltype, &expr->right, "assignment"))
1439 return NULL;
1440 }
1441
1442 evaluate_assign_to(left, ltype);
1443
1444 expr->ctype = ltype;
1445 return ltype;
1446 }
1447
1448 static void examine_fn_arguments(struct symbol *fn)
1449 {
1450 struct symbol *s;
1451
1452 FOR_EACH_PTR(fn->arguments, s) {
1453 struct symbol *arg = evaluate_symbol(s);
1454 /* Array/function arguments silently degenerate into pointers */
1455 if (arg) {
1456 struct symbol *ptr;
1457 switch(arg->type) {
1458 case SYM_ARRAY:
1459 case SYM_FN:
1460 ptr = alloc_symbol(s->pos, SYM_PTR);
1461 if (arg->type == SYM_ARRAY)
1462 ptr->ctype = arg->ctype;
1463 else
1464 ptr->ctype.base_type = arg;
1465 ptr->ctype.as |= s->ctype.as;
1466 ptr->ctype.modifiers |= s->ctype.modifiers & MOD_PTRINHERIT;
1467
1468 s->ctype.base_type = ptr;
1469 s->ctype.as = 0;
1470 s->ctype.modifiers &= ~MOD_PTRINHERIT;
1471 s->bit_size = 0;
1472 s->examined = 0;
1473 examine_symbol_type(s);
1474 break;
1475 default:
1476 /* nothing */
1477 break;
1478 }
1479 }
1480 } END_FOR_EACH_PTR(s);
1481 }
1482
1483 static struct symbol *convert_to_as_mod(struct symbol *sym, int as, int mod)
1484 {
1485 /* Take the modifiers of the pointer, and apply them to the member */
1486 mod |= sym->ctype.modifiers;
1487 if (sym->ctype.as != as || sym->ctype.modifiers != mod) {
1488 struct symbol *newsym = alloc_symbol(sym->pos, SYM_NODE);
1489 *newsym = *sym;
1490 newsym->ctype.as = as;
1491 newsym->ctype.modifiers = mod;
1492 sym = newsym;
1493 }
1494 return sym;
1495 }
1496
1497 static struct symbol *create_pointer(struct expression *expr, struct symbol *sym, int degenerate)
1498 {
1499 struct symbol *node = alloc_symbol(expr->pos, SYM_NODE);
1500 struct symbol *ptr = alloc_symbol(expr->pos, SYM_PTR);
1501
1502 node->ctype.base_type = ptr;
1503 ptr->bit_size = bits_in_pointer;
1504 ptr->ctype.alignment = pointer_alignment;
1505
1506 node->bit_size = bits_in_pointer;
1507 node->ctype.alignment = pointer_alignment;
1508
1509 access_symbol(sym);
1510 if (sym->ctype.modifiers & MOD_REGISTER) {
1511 warning(expr->pos, "taking address of 'register' variable '%s'", show_ident(sym->ident));
1512 sym->ctype.modifiers &= ~MOD_REGISTER;
1513 }
1514 if (sym->type == SYM_NODE) {
1515 ptr->ctype.as |= sym->ctype.as;
1516 ptr->ctype.modifiers |= sym->ctype.modifiers & MOD_PTRINHERIT;
1517 sym = sym->ctype.base_type;
1518 }
1519 if (degenerate && sym->type == SYM_ARRAY) {
1520 ptr->ctype.as |= sym->ctype.as;
1521 ptr->ctype.modifiers |= sym->ctype.modifiers & MOD_PTRINHERIT;
1522 sym = sym->ctype.base_type;
1523 }
1524 ptr->ctype.base_type = sym;
1525
1526 return node;
1527 }
1528
1529 /* Arrays degenerate into pointers on pointer arithmetic */
1530 static struct symbol *degenerate(struct expression *expr)
1531 {
1532 struct symbol *ctype, *base;
1533
1534 if (!expr)
1535 return NULL;
1536 ctype = expr->ctype;
1537 if (!ctype)
1538 return NULL;
1539 base = examine_symbol_type(ctype);
1540 if (ctype->type == SYM_NODE)
1541 base = ctype->ctype.base_type;
1542 /*
1543 * Arrays degenerate into pointers to the entries, while
1544 * functions degenerate into pointers to themselves.
1545 * If array was part of non-lvalue compound, we create a copy
1546 * of that compound first and then act as if we were dealing with
1547 * the corresponding field in there.
1548 */
1549 switch (base->type) {
1550 case SYM_ARRAY:
1551 if (expr->type == EXPR_SLICE) {
1552 struct symbol *a = alloc_symbol(expr->pos, SYM_NODE);
1553 struct expression *e0, *e1, *e2, *e3, *e4;
1554
1555 a->ctype.base_type = expr->base->ctype;
1556 a->bit_size = expr->base->ctype->bit_size;
1557 a->array_size = expr->base->ctype->array_size;
1558
1559 e0 = alloc_expression(expr->pos, EXPR_SYMBOL);
1560 e0->symbol = a;
1561 e0->ctype = &lazy_ptr_ctype;
1562
1563 e1 = alloc_expression(expr->pos, EXPR_PREOP);
1564 e1->unop = e0;
1565 e1->op = '*';
1566 e1->ctype = expr->base->ctype; /* XXX */
1567
1568 e2 = alloc_expression(expr->pos, EXPR_ASSIGNMENT);
1569 e2->left = e1;
1570 e2->right = expr->base;
1571 e2->op = '=';
1572 e2->ctype = expr->base->ctype;
1573
1574 if (expr->r_bitpos) {
1575 e3 = alloc_expression(expr->pos, EXPR_BINOP);
1576 e3->op = '+';
1577 e3->left = e0;
1578 e3->right = alloc_const_expression(expr->pos,
1579 bits_to_bytes(expr->r_bitpos));
1580 e3->ctype = &lazy_ptr_ctype;
1581 } else {
1582 e3 = e0;
1583 }
1584
1585 e4 = alloc_expression(expr->pos, EXPR_COMMA);
1586 e4->left = e2;
1587 e4->right = e3;
1588 e4->ctype = &lazy_ptr_ctype;
1589
1590 expr->unop = e4;
1591 expr->type = EXPR_PREOP;
1592 expr->op = '*';
1593 }
1594 case SYM_FN:
1595 if (expr->op != '*' || expr->type != EXPR_PREOP) {
1596 expression_error(expr, "strange non-value function or array");
1597 return &bad_ctype;
1598 }
1599 *expr = *expr->unop;
1600 ctype = create_pointer(expr, ctype, 1);
1601 expr->ctype = ctype;
1602 default:
1603 /* nothing */;
1604 }
1605 return ctype;
1606 }
1607
1608 static struct symbol *evaluate_addressof(struct expression *expr)
1609 {
1610 struct expression *op = expr->unop;
1611 struct symbol *ctype;
1612
1613 if (op->op != '*' || op->type != EXPR_PREOP) {
1614 expression_error(expr, "not addressable");
1615 return NULL;
1616 }
1617 ctype = op->ctype;
1618 *expr = *op->unop;
1619 expr->flags = 0;
1620
1621 if (expr->type == EXPR_SYMBOL) {
1622 struct symbol *sym = expr->symbol;
1623 sym->ctype.modifiers |= MOD_ADDRESSABLE;
1624 }
1625
1626 /*
1627 * symbol expression evaluation is lazy about the type
1628 * of the sub-expression, so we may have to generate
1629 * the type here if so..
1630 */
1631 if (expr->ctype == &lazy_ptr_ctype) {
1632 ctype = create_pointer(expr, ctype, 0);
1633 expr->ctype = ctype;
1634 }
1635 return expr->ctype;
1636 }
1637
1638
1639 static struct symbol *evaluate_dereference(struct expression *expr)
1640 {
1641 struct expression *op = expr->unop;
1642 struct symbol *ctype = op->ctype, *node, *target;
1643
1644 /* Simplify: *&(expr) => (expr) */
1645 if (op->type == EXPR_PREOP && op->op == '&') {
1646 *expr = *op->unop;
1647 expr->flags = 0;
1648 return expr->ctype;
1649 }
1650
1651 /* Dereferencing a node drops all the node information. */
1652 if (ctype->type == SYM_NODE)
1653 ctype = ctype->ctype.base_type;
1654
1655 node = alloc_symbol(expr->pos, SYM_NODE);
1656 target = ctype->ctype.base_type;
1657
1658 switch (ctype->type) {
1659 default:
1660 expression_error(expr, "cannot dereference this type");
1661 return NULL;
1662 case SYM_PTR:
1663 node->ctype.modifiers = target->ctype.modifiers & MOD_SPECIFIER;
1664 merge_type(node, ctype);
1665 break;
1666
1667 case SYM_ARRAY:
1668 if (!lvalue_expression(op)) {
1669 expression_error(op, "non-lvalue array??");
1670 return NULL;
1671 }
1672
1673 /* Do the implied "addressof" on the array */
1674 *op = *op->unop;
1675
1676 /*
1677 * When an array is dereferenced, we need to pick
1678 * up the attributes of the original node too..
1679 */
1680 merge_type(node, op->ctype);
1681 merge_type(node, ctype);
1682 break;
1683 }
1684
1685 node->bit_size = target->bit_size;
1686 node->array_size = target->array_size;
1687
1688 expr->ctype = node;
1689 return node;
1690 }
1691
1692 /*
1693 * Unary post-ops: x++ and x--
1694 */
1695 static struct symbol *evaluate_postop(struct expression *expr)
1696 {
1697 struct expression *op = expr->unop;
1698 struct symbol *ctype = op->ctype;
1699 int class = classify_type(op->ctype, &ctype);
1700 int multiply = 0;
1701
1702 if (!lvalue_expression(expr->unop)) {
1703 expression_error(expr, "need lvalue expression for ++/--");
1704 return NULL;
1705 }
1706
1707 if ((class & TYPE_RESTRICT) && restricted_unop(expr->op, &ctype))
1708 return bad_expr_type(expr);
1709
1710 if (class & TYPE_NUM) {
1711 multiply = 1;
1712 } else if (class == TYPE_PTR) {
1713 struct symbol *target = examine_pointer_target(ctype);
1714 if (!is_function(target))
1715 multiply = bits_to_bytes(target->bit_size);
1716 }
1717
1718 if (multiply) {
1719 evaluate_assign_to(op, op->ctype);
1720 expr->op_value = multiply;
1721 expr->ctype = ctype;
1722 return ctype;
1723 }
1724
1725 expression_error(expr, "bad argument type for ++/--");
1726 return NULL;
1727 }
1728
1729 static struct symbol *evaluate_sign(struct expression *expr)
1730 {
1731 struct symbol *ctype = expr->unop->ctype;
1732 int class = classify_type(ctype, &ctype);
1733 if (expr->flags && !(expr->unop->flags & Int_const_expr))
1734 expr->flags = 0;
1735 /* should be an arithmetic type */
1736 if (!(class & TYPE_NUM))
1737 return bad_expr_type(expr);
1738 if (!(class & (TYPE_FLOAT|TYPE_RESTRICT))) {
1739 struct symbol *rtype = integer_promotion(ctype);
1740 expr->unop = cast_to(expr->unop, rtype);
1741 ctype = rtype;
1742 } else if ((class & TYPE_FLOAT) && expr->op != '~') {
1743 /* no conversions needed */
1744 } else if ((class & TYPE_RESTRICT) && !restricted_unop(expr->op, &ctype)) {
1745 /* no conversions needed */
1746 } else {
1747 return bad_expr_type(expr);
1748 }
1749 if (expr->op == '+')
1750 *expr = *expr->unop;
1751 expr->ctype = ctype;
1752 return ctype;
1753 }
1754
1755 static struct symbol *evaluate_preop(struct expression *expr)
1756 {
1757 struct symbol *ctype = expr->unop->ctype;
1758
1759 switch (expr->op) {
1760 case '(':
1761 *expr = *expr->unop;
1762 return ctype;
1763
1764 case '+':
1765 case '-':
1766 case '~':
1767 return evaluate_sign(expr);
1768
1769 case '*':
1770 return evaluate_dereference(expr);
1771
1772 case '&':
1773 return evaluate_addressof(expr);
1774
1775 case SPECIAL_INCREMENT:
1776 case SPECIAL_DECREMENT:
1777 /*
1778 * From a type evaluation standpoint the preops are
1779 * the same as the postops
1780 */
1781 return evaluate_postop(expr);
1782
1783 case '!':
1784 if (expr->flags && !(expr->unop->flags & Int_const_expr))
1785 expr->flags = 0;
1786 if (is_safe_type(ctype))
1787 warning(expr->pos, "testing a 'safe expression'");
1788 if (is_float_type(ctype)) {
1789 struct expression *arg = expr->unop;
1790 expr->type = EXPR_BINOP;
1791 expr->op = SPECIAL_EQUAL;
1792 expr->left = arg;
1793 expr->right = alloc_expression(expr->pos, EXPR_FVALUE);
1794 expr->right->ctype = ctype;
1795 expr->right->fvalue = 0;
1796 } else if (is_fouled_type(ctype)) {
1797 warning(expr->pos, "%s degrades to integer",
1798 show_typename(ctype->ctype.base_type));
1799 }
1800 ctype = &bool_ctype;
1801 break;
1802
1803 default:
1804 break;
1805 }
1806 expr->ctype = ctype;
1807 return &bool_ctype;
1808 }
1809
1810 static struct symbol *find_identifier(struct ident *ident, struct symbol_list *_list, int *offset)
1811 {
1812 struct ptr_list *head = (struct ptr_list *)_list;
1813 struct ptr_list *list = head;
1814
1815 if (!head)
1816 return NULL;
1817 do {
1818 int i;
1819 for (i = 0; i < list->nr; i++) {
1820 struct symbol *sym = (struct symbol *) list->list[i];
1821 if (sym->ident) {
1822 if (sym->ident != ident)
1823 continue;
1824 *offset = sym->offset;
1825 return sym;
1826 } else {
1827 struct symbol *ctype = sym->ctype.base_type;
1828 struct symbol *sub;
1829 if (!ctype)
1830 continue;
1831 if (ctype->type != SYM_UNION && ctype->type != SYM_STRUCT)
1832 continue;
1833 sub = find_identifier(ident, ctype->symbol_list, offset);
1834 if (!sub)
1835 continue;
1836 *offset += sym->offset;
1837 return sub;
1838 }
1839 }
1840 } while ((list = list->next) != head);
1841 return NULL;
1842 }
1843
1844 static struct expression *evaluate_offset(struct expression *expr, unsigned long offset)
1845 {
1846 struct expression *add;
1847
1848 /*
1849 * Create a new add-expression
1850 *
1851 * NOTE! Even if we just add zero, we need a new node
1852 * for the member pointer, since it has a different
1853 * type than the original pointer. We could make that
1854 * be just a cast, but the fact is, a node is a node,
1855 * so we might as well just do the "add zero" here.
1856 */
1857 add = alloc_expression(expr->pos, EXPR_BINOP);
1858 add->op = '+';
1859 add->left = expr;
1860 add->right = alloc_expression(expr->pos, EXPR_VALUE);
1861 add->right->ctype = &int_ctype;
1862 add->right->value = offset;
1863
1864 /*
1865 * The ctype of the pointer will be lazily evaluated if
1866 * we ever take the address of this member dereference..
1867 */
1868 add->ctype = &lazy_ptr_ctype;
1869 return add;
1870 }
1871
1872 /* structure/union dereference */
1873 static struct symbol *evaluate_member_dereference(struct expression *expr)
1874 {
1875 int offset;
1876 struct symbol *ctype, *member;
1877 struct expression *deref = expr->deref, *add;
1878 struct ident *ident = expr->member;
1879 unsigned int mod;
1880 int address_space;
1881
1882 if (!evaluate_expression(deref))
1883 return NULL;
1884 if (!ident) {
1885 expression_error(expr, "bad member name");
1886 return NULL;
1887 }
1888
1889 ctype = deref->ctype;
1890 examine_symbol_type(ctype);
1891 address_space = ctype->ctype.as;
1892 mod = ctype->ctype.modifiers;
1893 if (ctype->type == SYM_NODE) {
1894 ctype = ctype->ctype.base_type;
1895 address_space |= ctype->ctype.as;
1896 mod |= ctype->ctype.modifiers;
1897 }
1898 if (!ctype || (ctype->type != SYM_STRUCT && ctype->type != SYM_UNION)) {
1899 expression_error(expr, "expected structure or union");
1900 return NULL;
1901 }
1902 offset = 0;
1903 member = find_identifier(ident, ctype->symbol_list, &offset);
1904 if (!member) {
1905 const char *type = ctype->type == SYM_STRUCT ? "struct" : "union";
1906 const char *name = "<unnamed>";
1907 int namelen = 9;
1908 if (ctype->ident) {
1909 name = ctype->ident->name;
1910 namelen = ctype->ident->len;
1911 }
1912 if (ctype->symbol_list)
1913 expression_error(expr, "no member '%s' in %s %.*s",
1914 show_ident(ident), type, namelen, name);
1915 else
1916 expression_error(expr, "using member '%s' in "
1917 "incomplete %s %.*s", show_ident(ident),
1918 type, namelen, name);
1919 return NULL;
1920 }
1921
1922 /*
1923 * The member needs to take on the address space and modifiers of
1924 * the "parent" type.
1925 */
1926 member = convert_to_as_mod(member, address_space, mod);
1927 ctype = get_base_type(member);
1928
1929 if (!lvalue_expression(deref)) {
1930 if (deref->type != EXPR_SLICE) {
1931 expr->base = deref;
1932 expr->r_bitpos = 0;
1933 } else {
1934 expr->base = deref->base;
1935 expr->r_bitpos = deref->r_bitpos;
1936 }
1937 expr->r_bitpos += bytes_to_bits(offset);
1938 expr->type = EXPR_SLICE;
1939 expr->r_nrbits = member->bit_size;
1940 expr->r_bitpos += member->bit_offset;
1941 expr->ctype = member;
1942 return member;
1943 }
1944
1945 deref = deref->unop;
1946 expr->deref = deref;
1947
1948 add = evaluate_offset(deref, offset);
1949 expr->type = EXPR_PREOP;
1950 expr->op = '*';
1951 expr->unop = add;
1952
1953 expr->ctype = member;
1954 return member;
1955 }
1956
1957 static int is_promoted(struct expression *expr)
1958 {
1959 while (1) {
1960 switch (expr->type) {
1961 case EXPR_BINOP:
1962 case EXPR_SELECT:
1963 case EXPR_CONDITIONAL:
1964 return 1;
1965 case EXPR_COMMA:
1966 expr = expr->right;
1967 continue;
1968 case EXPR_PREOP:
1969 switch (expr->op) {
1970 case '(':
1971 expr = expr->unop;
1972 continue;
1973 case '+':
1974 case '-':
1975 case '~':
1976 return 1;
1977 default:
1978 return 0;
1979 }
1980 default:
1981 return 0;
1982 }
1983 }
1984 }
1985
1986
1987 static struct symbol *evaluate_cast(struct expression *);
1988
1989 static struct symbol *evaluate_type_information(struct expression *expr)
1990 {
1991 struct symbol *sym = expr->cast_type;
1992 if (!sym) {
1993 sym = evaluate_expression(expr->cast_expression);
1994 if (!sym)
1995 return NULL;
1996 /*
1997 * Expressions of restricted types will possibly get
1998 * promoted - check that here
1999 */
2000 if (is_restricted_type(sym)) {
2001 if (sym->bit_size < bits_in_int && is_promoted(expr))
2002 sym = &int_ctype;
2003 } else if (is_fouled_type(sym)) {
2004 sym = &int_ctype;
2005 }
2006 }
2007 examine_symbol_type(sym);
2008 if (is_bitfield_type(sym)) {
2009 expression_error(expr, "trying to examine bitfield type");
2010 return NULL;
2011 }
2012 return sym;
2013 }
2014
2015 static struct symbol *evaluate_sizeof(struct expression *expr)
2016 {
2017 struct symbol *type;
2018 int size;
2019
2020 type = evaluate_type_information(expr);
2021 if (!type)
2022 return NULL;
2023
2024 size = type->bit_size;
2025
2026 if (size < 0 && is_void_type(type)) {
2027 warning(expr->pos, "expression using sizeof(void)");
2028 size = bits_in_char;
2029 }
2030
2031 if (size == 1 && is_bool_type(type)) {
2032 warning(expr->pos, "expression using sizeof bool");
2033 size = bits_in_char;
2034 }
2035
2036 if (is_function(type->ctype.base_type)) {
2037 warning(expr->pos, "expression using sizeof on a function");
2038 size = bits_in_char;
2039 }
2040
2041 if ((size < 0) || (size & (bits_in_char - 1)))
2042 expression_error(expr, "cannot size expression");
2043
2044 expr->type = EXPR_VALUE;
2045 expr->value = bits_to_bytes(size);
2046 expr->taint = 0;
2047 expr->ctype = size_t_ctype;
2048 return size_t_ctype;
2049 }
2050
2051 static struct symbol *evaluate_ptrsizeof(struct expression *expr)
2052 {
2053 struct symbol *type;
2054 int size;
2055
2056 type = evaluate_type_information(expr);
2057 if (!type)
2058 return NULL;
2059
2060 if (type->type == SYM_NODE)
2061 type = type->ctype.base_type;
2062 if (!type)
2063 return NULL;
2064 switch (type->type) {
2065 case SYM_ARRAY:
2066 break;
2067 case SYM_PTR:
2068 type = get_base_type(type);
2069 if (type)
2070 break;
2071 default:
2072 expression_error(expr, "expected pointer expression");
2073 return NULL;
2074 }
2075 size = type->bit_size;
2076 if (size & (bits_in_char-1))
2077 size = 0;
2078 expr->type = EXPR_VALUE;
2079 expr->value = bits_to_bytes(size);
2080 expr->taint = 0;
2081 expr->ctype = size_t_ctype;
2082 return size_t_ctype;
2083 }
2084
2085 static struct symbol *evaluate_alignof(struct expression *expr)
2086 {
2087 struct symbol *type;
2088
2089 type = evaluate_type_information(expr);
2090 if (!type)
2091 return NULL;
2092
2093 expr->type = EXPR_VALUE;
2094 expr->value = type->ctype.alignment;
2095 expr->taint = 0;
2096 expr->ctype = size_t_ctype;
2097 return size_t_ctype;
2098 }
2099
2100 static int evaluate_arguments(struct symbol *f, struct symbol *fn, struct expression_list *head)
2101 {
2102 struct expression *expr;
2103 struct symbol_list *argument_types = fn->arguments;
2104 struct symbol *argtype;
2105 int i = 1;
2106
2107 PREPARE_PTR_LIST(argument_types, argtype);
2108 FOR_EACH_PTR (head, expr) {
2109 struct expression **p = THIS_ADDRESS(expr);
2110 struct symbol *ctype, *target;
2111 ctype = evaluate_expression(expr);
2112
2113 if (!ctype)
2114 return 0;
2115
2116 target = argtype;
2117 if (!target) {
2118 struct symbol *type;
2119 int class = classify_type(ctype, &type);
2120 if (is_int(class)) {
2121 *p = cast_to(expr, integer_promotion(type));
2122 } else if (class & TYPE_FLOAT) {
2123 unsigned long mod = type->ctype.modifiers;
2124 if (!(mod & (MOD_LONG_ALL)))
2125 *p = cast_to(expr, &double_ctype);
2126 } else if (class & TYPE_PTR) {
2127 if (expr->ctype == &null_ctype)
2128 *p = cast_to(expr, &ptr_ctype);
2129 else
2130 degenerate(expr);
2131 }
2132 } else {
2133 static char where[30];
2134 examine_symbol_type(target);
2135 sprintf(where, "argument %d", i);
2136 compatible_assignment_types(expr, target, p, where);
2137 }
2138
2139 i++;
2140 NEXT_PTR_LIST(argtype);
2141 } END_FOR_EACH_PTR(expr);
2142 FINISH_PTR_LIST(argtype);
2143 return 1;
2144 }
2145
2146 static struct symbol *find_struct_ident(struct symbol *ctype, struct ident *ident)
2147 {
2148 struct symbol *sym;
2149
2150 FOR_EACH_PTR(ctype->symbol_list, sym) {
2151 if (sym->ident == ident)
2152 return sym;
2153 } END_FOR_EACH_PTR(sym);
2154 return NULL;
2155 }
2156
2157 static void convert_index(struct expression *e)
2158 {
2159 struct expression *child = e->idx_expression;
2160 unsigned from = e->idx_from;
2161 unsigned to = e->idx_to + 1;
2162 e->type = EXPR_POS;
2163 e->init_offset = from * bits_to_bytes(e->ctype->bit_size);
2164 e->init_nr = to - from;
2165 e->init_expr = child;
2166 }
2167
2168 static void convert_ident(struct expression *e)
2169 {
2170 struct expression *child = e->ident_expression;
2171 struct symbol *sym = e->field;
2172 e->type = EXPR_POS;
2173 e->init_offset = sym->offset;
2174 e->init_nr = 1;
2175 e->init_expr = child;
2176 }
2177
2178 static void convert_designators(struct expression *e)
2179 {
2180 while (e) {
2181 if (e->type == EXPR_INDEX)
2182 convert_index(e);
2183 else if (e->type == EXPR_IDENTIFIER)
2184 convert_ident(e);
2185 else
2186 break;
2187 e = e->init_expr;
2188 }
2189 }
2190
2191 static void excess(struct expression *e, const char *s)
2192 {
2193 warning(e->pos, "excessive elements in %s initializer", s);
2194 }
2195
2196 /*
2197 * implicit designator for the first element
2198 */
2199 static struct expression *first_subobject(struct symbol *ctype, int class,
2200 struct expression **v)
2201 {
2202 struct expression *e = *v, *new;
2203
2204 if (ctype->type == SYM_NODE)
2205 ctype = ctype->ctype.base_type;
2206
2207 if (class & TYPE_PTR) { /* array */
2208 if (!ctype->bit_size)
2209 return NULL;
2210 new = alloc_expression(e->pos, EXPR_INDEX);
2211 new->idx_expression = e;
2212 new->ctype = ctype->ctype.base_type;
2213 } else {
2214 struct symbol *field, *p;
2215 PREPARE_PTR_LIST(ctype->symbol_list, p);
2216 while (p && !p->ident && is_bitfield_type(p))
2217 NEXT_PTR_LIST(p);
2218 field = p;
2219 FINISH_PTR_LIST(p);
2220 if (!field)
2221 return NULL;
2222 new = alloc_expression(e->pos, EXPR_IDENTIFIER);
2223 new->ident_expression = e;
2224 new->field = new->ctype = field;
2225 }
2226 *v = new;
2227 return new;
2228 }
2229
2230 /*
2231 * sanity-check explicit designators; return the innermost one or NULL
2232 * in case of error. Assign types.
2233 */
2234 static struct expression *check_designators(struct expression *e,
2235 struct symbol *ctype)
2236 {
2237 struct expression *last = NULL;
2238 const char *err;
2239 while (1) {
2240 if (ctype->type == SYM_NODE)
2241 ctype = ctype->ctype.base_type;
2242 if (e->type == EXPR_INDEX) {
2243 struct symbol *type;
2244 if (ctype->type != SYM_ARRAY) {
2245 err = "array index in non-array";
2246 break;
2247 }
2248 type = ctype->ctype.base_type;
2249 if (ctype->bit_size >= 0 && type->bit_size >= 0) {
2250 unsigned offset = e->idx_to * type->bit_size;
2251 if (offset >= ctype->bit_size) {
2252 err = "index out of bounds in";
2253 break;
2254 }
2255 }
2256 e->ctype = ctype = type;
2257 ctype = type;
2258 last = e;
2259 if (!e->idx_expression) {
2260 err = "invalid";
2261 break;
2262 }
2263 e = e->idx_expression;
2264 } else if (e->type == EXPR_IDENTIFIER) {
2265 if (ctype->type != SYM_STRUCT && ctype->type != SYM_UNION) {
2266 err = "field name not in struct or union";
2267 break;
2268 }
2269 ctype = find_struct_ident(ctype, e->expr_ident);
2270 if (!ctype) {
2271 err = "unknown field name in";
2272 break;
2273 }
2274 e->field = e->ctype = ctype;
2275 last = e;
2276 if (!e->ident_expression) {
2277 err = "invalid";
2278 break;
2279 }
2280 e = e->ident_expression;
2281 } else if (e->type == EXPR_POS) {
2282 err = "internal front-end error: EXPR_POS in";
2283 break;
2284 } else
2285 return last;
2286 }
2287 expression_error(e, "%s initializer", err);
2288 return NULL;
2289 }
2290
2291 /*
2292 * choose the next subobject to initialize.
2293 *
2294 * Get designators for next element, switch old ones to EXPR_POS.
2295 * Return the resulting expression or NULL if we'd run out of subobjects.
2296 * The innermost designator is returned in *v. Designators in old
2297 * are assumed to be already sanity-checked.
2298 */
2299 static struct expression *next_designators(struct expression *old,
2300 struct symbol *ctype,
2301 struct expression *e, struct expression **v)
2302 {
2303 struct expression *new = NULL;
2304
2305 if (!old)
2306 return NULL;
2307 if (old->type == EXPR_INDEX) {
2308 struct expression *copy;
2309 unsigned n;
2310
2311 copy = next_designators(old->idx_expression,
2312 old->ctype, e, v);
2313 if (!copy) {
2314 n = old->idx_to + 1;
2315 if (n * old->ctype->bit_size == ctype->bit_size) {
2316 convert_index(old);
2317 return NULL;
2318 }
2319 copy = e;
2320 *v = new = alloc_expression(e->pos, EXPR_INDEX);
2321 } else {
2322 n = old->idx_to;
2323 new = alloc_expression(e->pos, EXPR_INDEX);
2324 }
2325
2326 new->idx_from = new->idx_to = n;
2327 new->idx_expression = copy;
2328 new->ctype = old->ctype;
2329 convert_index(old);
2330 } else if (old->type == EXPR_IDENTIFIER) {
2331 struct expression *copy;
2332 struct symbol *field;
2333
2334 copy = next_designators(old->ident_expression,
2335 old->ctype, e, v);
2336 if (!copy) {
2337 field = old->field->next_subobject;
2338 if (!field) {
2339 convert_ident(old);
2340 return NULL;
2341 }
2342 copy = e;
2343 *v = new = alloc_expression(e->pos, EXPR_IDENTIFIER);
2344 } else {
2345 field = old->field;
2346 new = alloc_expression(e->pos, EXPR_IDENTIFIER);
2347 }
2348
2349 new->field = field;
2350 new->expr_ident = field->ident;
2351 new->ident_expression = copy;
2352 new->ctype = field;
2353 convert_ident(old);
2354 }
2355 return new;
2356 }
2357
2358 static int handle_simple_initializer(struct expression **ep, int nested,
2359 int class, struct symbol *ctype);
2360
2361 /*
2362 * deal with traversing subobjects [6.7.8(17,18,20)]
2363 */
2364 static void handle_list_initializer(struct expression *expr,
2365 int class, struct symbol *ctype)
2366 {
2367 struct expression *e, *last = NULL, *top = NULL, *next;
2368 int jumped = 0;
2369
2370 FOR_EACH_PTR(expr->expr_list, e) {
2371 struct expression **v;
2372 struct symbol *type;
2373 int lclass;
2374
2375 if (e->type != EXPR_INDEX && e->type != EXPR_IDENTIFIER) {
2376 struct symbol *struct_sym;
2377 if (!top) {
2378 top = e;
2379 last = first_subobject(ctype, class, &top);
2380 } else {
2381 last = next_designators(last, ctype, e, &top);
2382 }
2383 if (!last) {
2384 excess(e, class & TYPE_PTR ? "array" :
2385 "struct or union");
2386 DELETE_CURRENT_PTR(e);
2387 continue;
2388 }
2389 struct_sym = ctype->type == SYM_NODE ? ctype->ctype.base_type : ctype;
2390 if (Wdesignated_init && struct_sym->designated_init)
2391 warning(e->pos, "%s%.*s%spositional init of field in %s %s, declared with attribute designated_init",
2392 ctype->ident ? "in initializer for " : "",
2393 ctype->ident ? ctype->ident->len : 0,
2394 ctype->ident ? ctype->ident->name : "",
2395 ctype->ident ? ": " : "",
2396 get_type_name(struct_sym->type),
2397 show_ident(struct_sym->ident));
2398 if (jumped) {
2399 warning(e->pos, "advancing past deep designator");
2400 jumped = 0;
2401 }
2402 REPLACE_CURRENT_PTR(e, last);
2403 } else {
2404 next = check_designators(e, ctype);
2405 if (!next) {
2406 DELETE_CURRENT_PTR(e);
2407 continue;
2408 }
2409 top = next;
2410 /* deeper than one designator? */
2411 jumped = top != e;
2412 convert_designators(last);
2413 last = e;
2414 }
2415
2416 found:
2417 lclass = classify_type(top->ctype, &type);
2418 if (top->type == EXPR_INDEX)
2419 v = &top->idx_expression;
2420 else
2421 v = &top->ident_expression;
2422
2423 if (handle_simple_initializer(v, 1, lclass, top->ctype))
2424 continue;
2425
2426 if (!(lclass & TYPE_COMPOUND)) {
2427 warning(e->pos, "bogus scalar initializer");
2428 DELETE_CURRENT_PTR(e);
2429 continue;
2430 }
2431
2432 next = first_subobject(type, lclass, v);
2433 if (next) {
2434 warning(e->pos, "missing braces around initializer");
2435 top = next;
2436 goto found;
2437 }
2438
2439 DELETE_CURRENT_PTR(e);
2440 excess(e, lclass & TYPE_PTR ? "array" : "struct or union");
2441
2442 } END_FOR_EACH_PTR(e);
2443
2444 convert_designators(last);
2445 expr->ctype = ctype;
2446 }
2447
2448 static int is_string_literal(struct expression **v)
2449 {
2450 struct expression *e = *v;
2451 while (e && e->type == EXPR_PREOP && e->op == '(')
2452 e = e->unop;
2453 if (!e || e->type != EXPR_STRING)
2454 return 0;
2455 if (e != *v && Wparen_string)
2456 warning(e->pos,
2457 "array initialized from parenthesized string constant");
2458 *v = e;
2459 return 1;
2460 }
2461
2462 /*
2463 * We want a normal expression, possibly in one layer of braces. Warn
2464 * if the latter happens inside a list (it's legal, but likely to be
2465 * an effect of screwup). In case of anything not legal, we are definitely
2466 * having an effect of screwup, so just fail and let the caller warn.
2467 */
2468 static struct expression *handle_scalar(struct expression *e, int nested)
2469 {
2470 struct expression *v = NULL, *p;
2471 int count = 0;
2472
2473 /* normal case */
2474 if (e->type != EXPR_INITIALIZER)
2475 return e;
2476
2477 FOR_EACH_PTR(e->expr_list, p) {
2478 if (!v)
2479 v = p;
2480 count++;
2481 } END_FOR_EACH_PTR(p);
2482 if (count != 1)
2483 return NULL;
2484 switch(v->type) {
2485 case EXPR_INITIALIZER:
2486 case EXPR_INDEX:
2487 case EXPR_IDENTIFIER:
2488 return NULL;
2489 default:
2490 break;
2491 }
2492 if (nested)
2493 warning(e->pos, "braces around scalar initializer");
2494 return v;
2495 }
2496
2497 /*
2498 * deal with the cases that don't care about subobjects:
2499 * scalar <- assignment expression, possibly in braces [6.7.8(11)]
2500 * character array <- string literal, possibly in braces [6.7.8(14)]
2501 * struct or union <- assignment expression of compatible type [6.7.8(13)]
2502 * compound type <- initializer list in braces [6.7.8(16)]
2503 * The last one punts to handle_list_initializer() which, in turn will call
2504 * us for individual elements of the list.
2505 *
2506 * We do not handle 6.7.8(15) (wide char array <- wide string literal) for
2507 * the lack of support of wide char stuff in general.
2508 *
2509 * One note: we need to take care not to evaluate a string literal until
2510 * we know that we *will* handle it right here. Otherwise we would screw
2511 * the cases like struct { struct {char s[10]; ...} ...} initialized with
2512 * { "string", ...} - we need to preserve that string literal recognizable
2513 * until we dig into the inner struct.
2514 */
2515 static int handle_simple_initializer(struct expression **ep, int nested,
2516 int class, struct symbol *ctype)
2517 {
2518 int is_string = is_string_type(ctype);
2519 struct expression *e = *ep, *p;
2520 struct symbol *type;
2521
2522 if (!e)
2523 return 0;
2524
2525 /* scalar */
2526 if (!(class & TYPE_COMPOUND)) {
2527 e = handle_scalar(e, nested);
2528 if (!e)
2529 return 0;
2530 *ep = e;
2531 if (!evaluate_expression(e))
2532 return 1;
2533 compatible_assignment_types(e, ctype, ep, "initializer");
2534 return 1;
2535 }
2536
2537 /*
2538 * sublist; either a string, or we dig in; the latter will deal with
2539 * pathologies, so we don't need anything fancy here.
2540 */
2541 if (e->type == EXPR_INITIALIZER) {
2542 if (is_string) {
2543 struct expression *v = NULL;
2544 int count = 0;
2545
2546 FOR_EACH_PTR(e->expr_list, p) {
2547 if (!v)
2548 v = p;
2549 count++;
2550 } END_FOR_EACH_PTR(p);
2551 if (count == 1 && is_string_literal(&v)) {
2552 *ep = e = v;
2553 goto String;
2554 }
2555 }
2556 handle_list_initializer(e, class, ctype);
2557 return 1;
2558 }
2559
2560 /* string */
2561 if (is_string_literal(&e)) {
2562 /* either we are doing array of char, or we'll have to dig in */
2563 if (is_string) {
2564 *ep = e;
2565 goto String;
2566 }
2567 return 0;
2568 }
2569 /* struct or union can be initialized by compatible */
2570 if (class != TYPE_COMPOUND)
2571 return 0;
2572 type = evaluate_expression(e);
2573 if (!type)
2574 return 0;
2575 if (ctype->type == SYM_NODE)
2576 ctype = ctype->ctype.base_type;
2577 if (type->type == SYM_NODE)
2578 type = type->ctype.base_type;
2579 if (ctype == type)
2580 return 1;
2581 return 0;
2582
2583 String:
2584 p = alloc_expression(e->pos, EXPR_STRING);
2585 *p = *e;
2586 type = evaluate_expression(p);
2587 if (ctype->bit_size != -1 &&
2588 ctype->bit_size + bits_in_char < type->bit_size) {
2589 warning(e->pos,
2590 "too long initializer-string for array of char");
2591 }
2592 *ep = p;
2593 return 1;
2594 }
2595
2596 static void evaluate_initializer(struct symbol *ctype, struct expression **ep)
2597 {
2598 struct symbol *type;
2599 int class = classify_type(ctype, &type);
2600 if (!handle_simple_initializer(ep, 0, class, ctype))
2601 expression_error(*ep, "invalid initializer");
2602 }
2603
2604 static struct symbol *evaluate_cast(struct expression *expr)
2605 {
2606 struct expression *target = expr->cast_expression;
2607 struct symbol *ctype;
2608 struct symbol *t1, *t2;
2609 int class1, class2;
2610 int as1 = 0, as2 = 0;
2611
2612 if (!target)
2613 return NULL;
2614
2615 /*
2616 * Special case: a cast can be followed by an
2617 * initializer, in which case we need to pass
2618 * the type value down to that initializer rather
2619 * than trying to evaluate it as an expression
2620 *
2621 * A more complex case is when the initializer is
2622 * dereferenced as part of a post-fix expression.
2623 * We need to produce an expression that can be dereferenced.
2624 */
2625 if (target->type == EXPR_INITIALIZER) {
2626 struct symbol *sym = expr->cast_type;
2627 struct expression *addr = alloc_expression(expr->pos, EXPR_SYMBOL);
2628
2629 sym->initializer = target;
2630 evaluate_symbol(sym);
2631
2632 addr->ctype = &lazy_ptr_ctype; /* Lazy eval */
2633 addr->symbol = sym;
2634
2635 expr->type = EXPR_PREOP;
2636 expr->op = '*';
2637 expr->unop = addr;
2638 expr->ctype = sym;
2639
2640 return sym;
2641 }
2642
2643 ctype = examine_symbol_type(expr->cast_type);
2644 expr->ctype = ctype;
2645 expr->cast_type = ctype;
2646
2647 evaluate_expression(target);
2648 degenerate(target);
2649
2650 class1 = classify_type(ctype, &t1);
2651
2652 /* cast to non-integer type -> not an integer constant expression */
2653 if (!is_int(class1))
2654 expr->flags = 0;
2655 /* if argument turns out to be not an integer constant expression *and*
2656 it was not a floating literal to start with -> too bad */
2657 else if (expr->flags == Int_const_expr &&
2658 !(target->flags & Int_const_expr))
2659 expr->flags = 0;
2660 /*
2661 * You can always throw a value away by casting to
2662 * "void" - that's an implicit "force". Note that
2663 * the same is _not_ true of "void *".
2664 */
2665 if (t1 == &void_ctype)
2666 goto out;
2667
2668 if (class1 & (TYPE_COMPOUND | TYPE_FN))
2669 warning(expr->pos, "cast to non-scalar");
2670
2671 t2 = target->ctype;
2672 if (!t2) {
2673 expression_error(expr, "cast from unknown type");
2674 goto out;
2675 }
2676 class2 = classify_type(t2, &t2);
2677
2678 if (class2 & TYPE_COMPOUND)
2679 warning(expr->pos, "cast from non-scalar");
2680
2681 if (expr->type == EXPR_FORCE_CAST)
2682 goto out;
2683
2684 /* allowed cast unfouls */
2685 if (class2 & TYPE_FOULED)
2686 t2 = unfoul(t2);
2687
2688 if (t1 != t2) {
2689 if (class1 & TYPE_RESTRICT)
2690 warning(expr->pos, "cast to %s",
2691 show_typename(t1));
2692 if (class2 & TYPE_RESTRICT)
2693 warning(expr->pos, "cast from %s",
2694 show_typename(t2));
2695 }
2696
2697 if (t1 == &ulong_ctype)
2698 as1 = -1;
2699 else if (class1 == TYPE_PTR) {
2700 examine_pointer_target(t1);
2701 as1 = t1->ctype.as;
2702 }
2703
2704 if (t2 == &ulong_ctype)
2705 as2 = -1;
2706 else if (class2 == TYPE_PTR) {
2707 examine_pointer_target(t2);
2708 as2 = t2->ctype.as;
2709 }
2710
2711 if (!as1 && as2 > 0)
2712 warning(expr->pos, "cast removes address space of expression");
2713 if (as1 > 0 && as2 > 0 && as1 != as2)
2714 warning(expr->pos, "cast between address spaces (<asn:%d>-><asn:%d>)", as2, as1);
2715 if (as1 > 0 && !as2 &&
2716 !is_null_pointer_constant(target) && Wcast_to_as)
2717 warning(expr->pos,
2718 "cast adds address space to expression (<asn:%d>)", as1);
2719
2720 if (!(t1->ctype.modifiers & MOD_PTRINHERIT) && class1 == TYPE_PTR &&
2721 !as1 && (target->flags & Int_const_expr)) {
2722 if (t1->ctype.base_type == &void_ctype) {
2723 if (is_zero_constant(target)) {
2724 /* NULL */
2725 expr->type = EXPR_VALUE;
2726 expr->ctype = &null_ctype;
2727 expr->value = 0;
2728 return ctype;
2729 }
2730 }
2731 }
2732 out:
2733 return ctype;
2734 }
2735
2736 /*
2737 * Evaluate a call expression with a symbol. This
2738 * should expand inline functions, and evaluate
2739 * builtins.
2740 */
2741 static int evaluate_symbol_call(struct expression *expr)
2742 {
2743 struct expression *fn = expr->fn;
2744 struct symbol *ctype = fn->ctype;
2745
2746 if (fn->type != EXPR_PREOP)
2747 return 0;
2748
2749 if (ctype->op && ctype->op->evaluate)
2750 return ctype->op->evaluate(expr);
2751
2752 if (ctype->ctype.modifiers & MOD_INLINE) {
2753 int ret;
2754 struct symbol *curr = current_fn;
2755
2756 if (ctype->definition)
2757 ctype = ctype->definition;
2758
2759 current_fn = ctype->ctype.base_type;
2760
2761 ret = inline_function(expr, ctype);
2762
2763 /* restore the old function */
2764 current_fn = curr;
2765 return ret;
2766 }
2767
2768 return 0;
2769 }
2770
2771 static struct symbol *evaluate_call(struct expression *expr)
2772 {
2773 int args, fnargs;
2774 struct symbol *ctype, *sym;
2775 struct expression *fn = expr->fn;
2776 struct expression_list *arglist = expr->args;
2777
2778 if (!evaluate_expression(fn))
2779 return NULL;
2780 sym = ctype = fn->ctype;
2781 if (ctype->type == SYM_NODE)
2782 ctype = ctype->ctype.base_type;
2783 if (ctype->type == SYM_PTR)
2784 ctype = get_base_type(ctype);
2785
2786 if (ctype->type != SYM_FN) {
2787 struct expression *arg;
2788 expression_error(expr, "not a function %s",
2789 show_ident(sym->ident));
2790 /* do typechecking in arguments */
2791 FOR_EACH_PTR (arglist, arg) {
2792 evaluate_expression(arg);
2793 } END_FOR_EACH_PTR(arg);
2794 return NULL;
2795 }
2796
2797 examine_fn_arguments(ctype);
2798 if (sym->type == SYM_NODE && fn->type == EXPR_PREOP &&
2799 sym->op && sym->op->args) {
2800 if (!sym->op->args(expr))
2801 return NULL;
2802 } else {
2803 if (!evaluate_arguments(sym, ctype, arglist))
2804 return NULL;
2805 args = expression_list_size(expr->args);
2806 fnargs = symbol_list_size(ctype->arguments);
2807 if (args < fnargs)
2808 expression_error(expr,
2809 "not enough arguments for function %s",
2810 show_ident(sym->ident));
2811 if (args > fnargs && !ctype->variadic)
2812 expression_error(expr,
2813 "too many arguments for function %s",
2814 show_ident(sym->ident));
2815 }
2816 if (sym->type == SYM_NODE) {
2817 if (evaluate_symbol_call(expr))
2818 return expr->ctype;
2819 }
2820 expr->ctype = ctype->ctype.base_type;
2821 return expr->ctype;
2822 }
2823
2824 static struct symbol *evaluate_offsetof(struct expression *expr)
2825 {
2826 struct expression *e = expr->down;
2827 struct symbol *ctype = expr->in;
2828 int class;
2829
2830 if (expr->op == '.') {
2831 struct symbol *field;
2832 int offset = 0;
2833 if (!ctype) {
2834 expression_error(expr, "expected structure or union");
2835 return NULL;
2836 }
2837 examine_symbol_type(ctype);
2838 class = classify_type(ctype, &ctype);
2839 if (class != TYPE_COMPOUND) {
2840 expression_error(expr, "expected structure or union");
2841 return NULL;
2842 }
2843
2844 field = find_identifier(expr->ident, ctype->symbol_list, &offset);
2845 if (!field) {
2846 expression_error(expr, "unknown member");
2847 return NULL;
2848 }
2849 ctype = field;
2850 expr->type = EXPR_VALUE;
2851 expr->flags = Int_const_expr;
2852 expr->value = offset;
2853 expr->taint = 0;
2854 expr->ctype = size_t_ctype;
2855 } else {
2856 if (!ctype) {
2857 expression_error(expr, "expected structure or union");
2858 return NULL;
2859 }
2860 examine_symbol_type(ctype);
2861 class = classify_type(ctype, &ctype);
2862 if (class != (TYPE_COMPOUND | TYPE_PTR)) {
2863 expression_error(expr, "expected array");
2864 return NULL;
2865 }
2866 ctype = ctype->ctype.base_type;
2867 if (!expr->index) {
2868 expr->type = EXPR_VALUE;
2869 expr->flags = Int_const_expr;
2870 expr->value = 0;
2871 expr->taint = 0;
2872 expr->ctype = size_t_ctype;
2873 } else {
2874 struct expression *idx = expr->index, *m;
2875 struct symbol *i_type = evaluate_expression(idx);
2876 int i_class = classify_type(i_type, &i_type);
2877 if (!is_int(i_class)) {
2878 expression_error(expr, "non-integer index");
2879 return NULL;
2880 }
2881 unrestrict(idx, i_class, &i_type);
2882 idx = cast_to(idx, size_t_ctype);
2883 m = alloc_const_expression(expr->pos,
2884 bits_to_bytes(ctype->bit_size));
2885 m->ctype = size_t_ctype;
2886 m->flags = Int_const_expr;
2887 expr->type = EXPR_BINOP;
2888 expr->left = idx;
2889 expr->right = m;
2890 expr->op = '*';
2891 expr->ctype = size_t_ctype;
2892 expr->flags = m->flags & idx->flags & Int_const_expr;
2893 }
2894 }
2895 if (e) {
2896 struct expression *copy = __alloc_expression(0);
2897 *copy = *expr;
2898 if (e->type == EXPR_OFFSETOF)
2899 e->in = ctype;
2900 if (!evaluate_expression(e))
2901 return NULL;
2902 expr->type = EXPR_BINOP;
2903 expr->flags = e->flags & copy->flags & Int_const_expr;
2904 expr->op = '+';
2905 expr->ctype = size_t_ctype;
2906 expr->left = copy;
2907 expr->right = e;
2908 }
2909 return size_t_ctype;
2910 }
2911
2912 struct symbol *evaluate_expression(struct expression *expr)
2913 {
2914 if (!expr)
2915 return NULL;
2916 if (expr->ctype)
2917 return expr->ctype;
2918
2919 switch (expr->type) {
2920 case EXPR_VALUE:
2921 case EXPR_FVALUE:
2922 expression_error(expr, "value expression without a type");
2923 return NULL;
2924 case EXPR_STRING:
2925 return evaluate_string(expr);
2926 case EXPR_SYMBOL:
2927 return evaluate_symbol_expression(expr);
2928 case EXPR_BINOP:
2929 if (!evaluate_expression(expr->left))
2930 return NULL;
2931 if (!evaluate_expression(expr->right))
2932 return NULL;
2933 return evaluate_binop(expr);
2934 case EXPR_LOGICAL:
2935 return evaluate_logical(expr);
2936 case EXPR_COMMA:
2937 evaluate_expression(expr->left);
2938 if (!evaluate_expression(expr->right))
2939 return NULL;
2940 return evaluate_comma(expr);
2941 case EXPR_COMPARE:
2942 if (!evaluate_expression(expr->left))
2943 return NULL;
2944 if (!evaluate_expression(expr->right))
2945 return NULL;
2946 return evaluate_compare(expr);
2947 case EXPR_ASSIGNMENT:
2948 if (!evaluate_expression(expr->left))
2949 return NULL;
2950 if (!evaluate_expression(expr->right))
2951 return NULL;
2952 return evaluate_assignment(expr);
2953 case EXPR_PREOP:
2954 if (!evaluate_expression(expr->unop))
2955 return NULL;
2956 return evaluate_preop(expr);
2957 case EXPR_POSTOP:
2958 if (!evaluate_expression(expr->unop))
2959 return NULL;
2960 return evaluate_postop(expr);
2961 case EXPR_CAST:
2962 case EXPR_FORCE_CAST:
2963 case EXPR_IMPLIED_CAST:
2964 return evaluate_cast(expr);
2965 case EXPR_SIZEOF:
2966 return evaluate_sizeof(expr);
2967 case EXPR_PTRSIZEOF:
2968 return evaluate_ptrsizeof(expr);
2969 case EXPR_ALIGNOF:
2970 return evaluate_alignof(expr);
2971 case EXPR_DEREF:
2972 return evaluate_member_dereference(expr);
2973 case EXPR_CALL:
2974 return evaluate_call(expr);
2975 case EXPR_SELECT:
2976 case EXPR_CONDITIONAL:
2977 return evaluate_conditional_expression(expr);
2978 case EXPR_STATEMENT:
2979 expr->ctype = evaluate_statement(expr->statement);
2980 return expr->ctype;
2981
2982 case EXPR_LABEL:
2983 expr->ctype = &ptr_ctype;
2984 return &ptr_ctype;
2985
2986 case EXPR_TYPE:
2987 /* Evaluate the type of the symbol .. */
2988 evaluate_symbol(expr->symbol);
2989 /* .. but the type of the _expression_ is a "type" */
2990 expr->ctype = &type_ctype;
2991 return &type_ctype;
2992
2993 case EXPR_OFFSETOF:
2994 return evaluate_offsetof(expr);
2995
2996 /* These can not exist as stand-alone expressions */
2997 case EXPR_INITIALIZER:
2998 case EXPR_IDENTIFIER:
2999 case EXPR_INDEX:
3000 case EXPR_POS:
3001 expression_error(expr, "internal front-end error: initializer in expression");
3002 return NULL;
3003 case EXPR_SLICE:
3004 expression_error(expr, "internal front-end error: SLICE re-evaluated");
3005 return NULL;
3006 }
3007 return NULL;
3008 }
3009
3010 static void check_duplicates(struct symbol *sym)
3011 {
3012 int declared = 0;
3013 struct symbol *next = sym;
3014
3015 while ((next = next->same_symbol) != NULL) {
3016 const char *typediff;
3017 evaluate_symbol(next);
3018 declared++;
3019 typediff = type_difference(&sym->ctype, &next->ctype, 0, 0);
3020 if (typediff) {
3021 sparse_error(sym->pos, "symbol '%s' redeclared with different type (originally declared at %s:%d) - %s",
3022 show_ident(sym->ident),
3023 stream_name(next->pos.stream), next->pos.line, typediff);
3024 return;
3025 }
3026 }
3027 if (!declared) {
3028 unsigned long mod = sym->ctype.modifiers;
3029 if (mod & (MOD_STATIC | MOD_REGISTER))
3030 return;
3031 if (!(mod & MOD_TOPLEVEL))
3032 return;
3033 if (!Wdecl)
3034 return;
3035 if (sym->ident == &main_ident)
3036 return;
3037 warning(sym->pos, "symbol '%s' was not declared. Should it be static?", show_ident(sym->ident));
3038 }
3039 }
3040
3041 static struct symbol *evaluate_symbol(struct symbol *sym)
3042 {
3043 struct symbol *base_type;
3044
3045 if (!sym)
3046 return sym;
3047 if (sym->evaluated)
3048 return sym;
3049 sym->evaluated = 1;
3050
3051 sym = examine_symbol_type(sym);
3052 base_type = get_base_type(sym);
3053 if (!base_type)
3054 return NULL;
3055
3056 /* Evaluate the initializers */
3057 if (sym->initializer)
3058 evaluate_initializer(sym, &sym->initializer);
3059
3060 /* And finally, evaluate the body of the symbol too */
3061 if (base_type->type == SYM_FN) {
3062 struct symbol *curr = current_fn;
3063
3064 if (sym->definition && sym->definition != sym)
3065 return evaluate_symbol(sym->definition);
3066
3067 current_fn = base_type;
3068
3069 examine_fn_arguments(base_type);
3070 if (!base_type->stmt && base_type->inline_stmt)
3071 uninline(sym);
3072 if (base_type->stmt)
3073 evaluate_statement(base_type->stmt);
3074
3075 current_fn = curr;
3076 }
3077
3078 return base_type;
3079 }
3080
3081 void evaluate_symbol_list(struct symbol_list *list)
3082 {
3083 struct symbol *sym;
3084
3085 FOR_EACH_PTR(list, sym) {
3086 evaluate_symbol(sym);
3087 check_duplicates(sym);
3088 } END_FOR_EACH_PTR(sym);
3089 }
3090
3091 static struct symbol *evaluate_return_expression(struct statement *stmt)
3092 {
3093 struct expression *expr = stmt->expression;
3094 struct symbol *fntype;
3095
3096 evaluate_expression(expr);
3097 fntype = current_fn->ctype.base_type;
3098 if (!fntype || fntype == &void_ctype) {
3099 if (expr && expr->ctype != &void_ctype)
3100 expression_error(expr, "return expression in %s function", fntype?"void":"typeless");
3101 if (expr && Wreturn_void)
3102 warning(stmt->pos, "returning void-valued expression");
3103 return NULL;
3104 }
3105
3106 if (!expr) {
3107 sparse_error(stmt->pos, "return with no return value");
3108 return NULL;
3109 }
3110 if (!expr->ctype)
3111 return NULL;
3112 compatible_assignment_types(expr, fntype, &stmt->expression, "return expression");
3113 return NULL;
3114 }
3115
3116 static void evaluate_if_statement(struct statement *stmt)
3117 {
3118 if (!stmt->if_conditional)
3119 return;
3120
3121 evaluate_conditional(stmt->if_conditional, 0);
3122 evaluate_statement(stmt->if_true);
3123 evaluate_statement(stmt->if_false);
3124 }
3125
3126 static void evaluate_iterator(struct statement *stmt)
3127 {
3128 evaluate_symbol_list(stmt->iterator_syms);
3129 evaluate_conditional(stmt->iterator_pre_condition, 1);
3130 evaluate_conditional(stmt->iterator_post_condition,1);
3131 evaluate_statement(stmt->iterator_pre_statement);
3132 evaluate_statement(stmt->iterator_statement);
3133 evaluate_statement(stmt->iterator_post_statement);
3134 }
3135
3136 static void verify_output_constraint(struct expression *expr, const char *constraint)
3137 {
3138 switch (*constraint) {
3139 case '=': /* Assignment */
3140 case '+': /* Update */
3141 break;
3142 default:
3143 expression_error(expr, "output constraint is not an assignment constraint (\"%s\")", constraint);
3144 }
3145 }
3146
3147 static void verify_input_constraint(struct expression *expr, const char *constraint)
3148 {
3149 switch (*constraint) {
3150 case '=': /* Assignment */
3151 case '+': /* Update */
3152 expression_error(expr, "input constraint with assignment (\"%s\")", constraint);
3153 }
3154 }
3155
3156 static void evaluate_asm_statement(struct statement *stmt)
3157 {
3158 struct expression *expr;
3159 struct symbol *sym;
3160 int state;
3161
3162 expr = stmt->asm_string;
3163 if (!expr || expr->type != EXPR_STRING) {
3164 sparse_error(stmt->pos, "need constant string for inline asm");
3165 return;
3166 }
3167
3168 state = 0;
3169 FOR_EACH_PTR(stmt->asm_outputs, expr) {
3170 switch (state) {
3171 case 0: /* Identifier */
3172 state = 1;
3173 continue;
3174
3175 case 1: /* Constraint */
3176 state = 2;
3177 if (!expr || expr->type != EXPR_STRING) {
3178 sparse_error(expr ? expr->pos : stmt->pos, "asm output constraint is not a string");
3179 *THIS_ADDRESS(expr) = NULL;
3180 continue;
3181 }
3182 verify_output_constraint(expr, expr->string->data);
3183 continue;
3184
3185 case 2: /* Expression */
3186 state = 0;
3187 if (!evaluate_expression(expr))
3188 return;
3189 if (!lvalue_expression(expr))
3190 warning(expr->pos, "asm output is not an lvalue");
3191 evaluate_assign_to(expr, expr->ctype);
3192 continue;
3193 }
3194 } END_FOR_EACH_PTR(expr);
3195
3196 state = 0;
3197 FOR_EACH_PTR(stmt->asm_inputs, expr) {
3198 switch (state) {
3199 case 0: /* Identifier */
3200 state = 1;
3201 continue;
3202
3203 case 1: /* Constraint */
3204 state = 2;
3205 if (!expr || expr->type != EXPR_STRING) {
3206 sparse_error(expr ? expr->pos : stmt->pos, "asm input constraint is not a string");
3207 *THIS_ADDRESS(expr) = NULL;
3208 continue;
3209 }
3210 verify_input_constraint(expr, expr->string->data);
3211 continue;
3212
3213 case 2: /* Expression */
3214 state = 0;
3215 if (!evaluate_expression(expr))
3216 return;
3217 continue;
3218 }
3219 } END_FOR_EACH_PTR(expr);
3220
3221 FOR_EACH_PTR(stmt->asm_clobbers, expr) {
3222 if (!expr) {
3223 sparse_error(stmt->pos, "bad asm clobbers");
3224 return;
3225 }
3226 if (expr->type == EXPR_STRING)
3227 continue;
3228 expression_error(expr, "asm clobber is not a string");
3229 } END_FOR_EACH_PTR(expr);
3230
3231 FOR_EACH_PTR(stmt->asm_labels, sym) {
3232 if (!sym || sym->type != SYM_LABEL) {
3233 sparse_error(stmt->pos, "bad asm label");
3234 return;
3235 }
3236 } END_FOR_EACH_PTR(sym);
3237 }
3238
3239 static void evaluate_case_statement(struct statement *stmt)
3240 {
3241 evaluate_expression(stmt->case_expression);
3242 evaluate_expression(stmt->case_to);
3243 evaluate_statement(stmt->case_statement);
3244 }
3245
3246 static void check_case_type(struct expression *switch_expr,
3247 struct expression *case_expr,
3248 struct expression **enumcase)
3249 {
3250 struct symbol *switch_type, *case_type;
3251 int sclass, cclass;
3252
3253 if (!case_expr)
3254 return;
3255
3256 switch_type = switch_expr->ctype;
3257 case_type = evaluate_expression(case_expr);
3258
3259 if (!switch_type || !case_type)
3260 goto Bad;
3261 if (enumcase) {
3262 if (*enumcase)
3263 warn_for_different_enum_types(case_expr->pos, case_type, (*enumcase)->ctype);
3264 else if (is_enum_type(case_type))
3265 *enumcase = case_expr;
3266 }
3267
3268 sclass = classify_type(switch_type, &switch_type);
3269 cclass = classify_type(case_type, &case_type);
3270
3271 /* both should be arithmetic */
3272 if (!(sclass & cclass & TYPE_NUM))
3273 goto Bad;
3274
3275 /* neither should be floating */
3276 if ((sclass | cclass) & TYPE_FLOAT)
3277 goto Bad;
3278
3279 /* if neither is restricted, we are OK */
3280 if (!((sclass | cclass) & TYPE_RESTRICT))
3281 return;
3282
3283 if (!restricted_binop_type(SPECIAL_EQUAL, case_expr, switch_expr,
3284 cclass, sclass, case_type, switch_type)) {
3285 unrestrict(case_expr, cclass, &case_type);
3286 unrestrict(switch_expr, sclass, &switch_type);
3287 }
3288 return;
3289
3290 Bad:
3291 expression_error(case_expr, "incompatible types for 'case' statement");
3292 }
3293
3294 static void evaluate_switch_statement(struct statement *stmt)
3295 {
3296 struct symbol *sym;
3297 struct expression *enumcase = NULL;
3298 struct expression **enumcase_holder = &enumcase;
3299 struct expression *sel = stmt->switch_expression;
3300
3301 evaluate_expression(sel);
3302 evaluate_statement(stmt->switch_statement);
3303 if (!sel)
3304 return;
3305 if (sel->ctype && is_enum_type(sel->ctype))
3306 enumcase_holder = NULL; /* Only check cases against switch */
3307
3308 FOR_EACH_PTR(stmt->switch_case->symbol_list, sym) {
3309 struct statement *case_stmt = sym->stmt;
3310 check_case_type(sel, case_stmt->case_expression, enumcase_holder);
3311 check_case_type(sel, case_stmt->case_to, enumcase_holder);
3312 } END_FOR_EACH_PTR(sym);
3313 }
3314
3315 struct symbol *evaluate_statement(struct statement *stmt)
3316 {
3317 if (!stmt)
3318 return NULL;
3319
3320 switch (stmt->type) {
3321 case STMT_DECLARATION: {
3322 struct symbol *s;
3323 FOR_EACH_PTR(stmt->declaration, s) {
3324 evaluate_symbol(s);
3325 } END_FOR_EACH_PTR(s);
3326 return NULL;
3327 }
3328
3329 case STMT_RETURN:
3330 return evaluate_return_expression(stmt);
3331
3332 case STMT_EXPRESSION:
3333 if (!evaluate_expression(stmt->expression))
3334 return NULL;
3335 if (stmt->expression->ctype == &null_ctype)
3336 stmt->expression = cast_to(stmt->expression, &ptr_ctype);
3337 return degenerate(stmt->expression);
3338
3339 case STMT_COMPOUND: {
3340 struct statement *s;
3341 struct symbol *type = NULL;
3342
3343 /* Evaluate the return symbol in the compound statement */
3344 evaluate_symbol(stmt->ret);
3345
3346 /*
3347 * Then, evaluate each statement, making the type of the
3348 * compound statement be the type of the last statement
3349 */
3350 type = evaluate_statement(stmt->args);
3351 FOR_EACH_PTR(stmt->stmts, s) {
3352 type = evaluate_statement(s);
3353 } END_FOR_EACH_PTR(s);
3354 if (!type)
3355 type = &void_ctype;
3356 return type;
3357 }
3358 case STMT_IF:
3359 evaluate_if_statement(stmt);
3360 return NULL;
3361 case STMT_ITERATOR:
3362 evaluate_iterator(stmt);
3363 return NULL;
3364 case STMT_SWITCH:
3365 evaluate_switch_statement(stmt);
3366 return NULL;
3367 case STMT_CASE:
3368 evaluate_case_statement(stmt);
3369 return NULL;
3370 case STMT_LABEL:
3371 return evaluate_statement(stmt->label_statement);
3372 case STMT_GOTO:
3373 evaluate_expression(stmt->goto_expression);
3374 return NULL;
3375 case STMT_NONE:
3376 break;
3377 case STMT_ASM:
3378 evaluate_asm_statement(stmt);
3379 return NULL;
3380 case STMT_CONTEXT:
3381 evaluate_expression(stmt->expression);
3382 return NULL;
3383 case STMT_RANGE:
3384 evaluate_expression(stmt->range_expression);
3385 evaluate_expression(stmt->range_low);
3386 evaluate_expression(stmt->range_high);
3387 return NULL;
3388 }
3389 return NULL;
3390 }
Static analysis for C