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[PATCH] tie the fields of struct in simple list
[smatch.git] / evaluate.c
blobf68b55eb0b0637b807bf661067f3036bd1433ade
1 /*
2 * sparse/evaluate.c
3 *
4 * Copyright (C) 2003 Transmeta Corp.
5 * 2003-2004 Linus Torvalds
6 *
7 * Licensed under the Open Software License version 1.1
8 *
9 * Evaluate constant expressions.
10 */
11 #include <stdlib.h>
12 #include <stdarg.h>
13 #include <stddef.h>
14 #include <stdio.h>
15 #include <string.h>
16 #include <ctype.h>
17 #include <unistd.h>
18 #include <fcntl.h>
19 #include <limits.h>
20
21 #include "lib.h"
22 #include "allocate.h"
23 #include "parse.h"
24 #include "token.h"
25 #include "symbol.h"
26 #include "target.h"
27 #include "expression.h"
28
29 struct symbol *current_fn;
30
31 static struct symbol *degenerate(struct expression *expr);
32 static struct symbol *evaluate_symbol(struct symbol *sym);
33
34 static struct symbol *evaluate_symbol_expression(struct expression *expr)
35 {
36 struct expression *addr;
37 struct symbol *sym = expr->symbol;
38 struct symbol *base_type;
39
40 if (!sym) {
41 expression_error(expr, "undefined identifier '%s'", show_ident(expr->symbol_name));
42 return NULL;
43 }
44
45 examine_symbol_type(sym);
46
47 base_type = get_base_type(sym);
48 if (!base_type) {
49 expression_error(expr, "identifier '%s' has no type", show_ident(expr->symbol_name));
50 return NULL;
51 }
52
53 addr = alloc_expression(expr->pos, EXPR_SYMBOL);
54 addr->symbol = sym;
55 addr->symbol_name = expr->symbol_name;
56 addr->ctype = &lazy_ptr_ctype; /* Lazy evaluation: we need to do a proper job if somebody does &sym */
57 expr->type = EXPR_PREOP;
58 expr->op = '*';
59 expr->unop = addr;
60
61 /* The type of a symbol is the symbol itself! */
62 expr->ctype = sym;
63 return sym;
64 }
65
66 static struct symbol *evaluate_string(struct expression *expr)
67 {
68 struct symbol *sym = alloc_symbol(expr->pos, SYM_NODE);
69 struct symbol *array = alloc_symbol(expr->pos, SYM_ARRAY);
70 struct expression *addr = alloc_expression(expr->pos, EXPR_SYMBOL);
71 struct expression *initstr = alloc_expression(expr->pos, EXPR_STRING);
72 unsigned int length = expr->string->length;
73
74 sym->array_size = alloc_const_expression(expr->pos, length);
75 sym->bit_size = bits_in_char * length;
76 sym->ctype.alignment = 1;
77 sym->string = 1;
78 sym->ctype.modifiers = MOD_STATIC;
79 sym->ctype.base_type = array;
80 sym->initializer = initstr;
81
82 initstr->ctype = sym;
83 initstr->string = expr->string;
84
85 array->array_size = sym->array_size;
86 array->bit_size = bits_in_char * length;
87 array->ctype.alignment = 1;
88 array->ctype.modifiers = MOD_STATIC;
89 array->ctype.base_type = &char_ctype;
90
91 addr->symbol = sym;
92 addr->ctype = &lazy_ptr_ctype;
93
94 expr->type = EXPR_PREOP;
95 expr->op = '*';
96 expr->unop = addr;
97 expr->ctype = sym;
98 return sym;
99 }
100
101 static inline struct symbol *integer_promotion(struct symbol *type)
102 {
103 struct symbol *orig_type = type;
104 unsigned long mod = type->ctype.modifiers;
105 int width;
106
107 if (type->type == SYM_NODE)
108 type = type->ctype.base_type;
109 if (type->type == SYM_ENUM)
110 type = type->ctype.base_type;
111 width = type->bit_size;
112
113 /*
114 * Bitfields always promote to the base type,
115 * even if the bitfield might be bigger than
116 * an "int".
117 */
118 if (type->type == SYM_BITFIELD) {
119 type = type->ctype.base_type;
120 orig_type = type;
121 }
122 mod = type->ctype.modifiers;
123 if (width < bits_in_int)
124 return &int_ctype;
125
126 /* If char/short has as many bits as int, it still gets "promoted" */
127 if (mod & (MOD_CHAR | MOD_SHORT)) {
128 if (mod & MOD_UNSIGNED)
129 return &uint_ctype;
130 return &int_ctype;
131 }
132 return orig_type;
133 }
134
135 /*
136 * integer part of usual arithmetic conversions:
137 * integer promotions are applied
138 * if left and right are identical, we are done
139 * if signedness is the same, convert one with lower rank
140 * unless unsigned argument has rank lower than signed one, convert the
141 * signed one.
142 * if signed argument is bigger than unsigned one, convert the unsigned.
143 * otherwise, convert signed.
144 *
145 * Leaving aside the integer promotions, that is equivalent to
146 * if identical, don't convert
147 * if left is bigger than right, convert right
148 * if right is bigger than left, convert right
149 * otherwise, if signedness is the same, convert one with lower rank
150 * otherwise convert the signed one.
151 */
152 static struct symbol *bigger_int_type(struct symbol *left, struct symbol *right)
153 {
154 unsigned long lmod, rmod;
155
156 left = integer_promotion(left);
157 right = integer_promotion(right);
158
159 if (left == right)
160 goto left;
161
162 if (left->bit_size > right->bit_size)
163 goto left;
164
165 if (right->bit_size > left->bit_size)
166 goto right;
167
168 lmod = left->ctype.modifiers;
169 rmod = right->ctype.modifiers;
170 if ((lmod ^ rmod) & MOD_UNSIGNED) {
171 if (lmod & MOD_UNSIGNED)
172 goto left;
173 } else if ((lmod & ~rmod) & (MOD_LONG | MOD_LONGLONG))
174 goto left;
175 right:
176 left = right;
177 left:
178 return left;
179 }
180
181 static int same_cast_type(struct symbol *orig, struct symbol *new)
182 {
183 return orig->bit_size == new->bit_size && orig->bit_offset == new->bit_offset;
184 }
185
186 static struct symbol *base_type(struct symbol *node, unsigned long *modp, unsigned long *asp)
187 {
188 unsigned long mod, as;
189
190 mod = 0; as = 0;
191 while (node) {
192 mod |= node->ctype.modifiers;
193 as |= node->ctype.as;
194 if (node->type == SYM_NODE) {
195 node = node->ctype.base_type;
196 continue;
197 }
198 break;
199 }
200 *modp = mod & ~MOD_IGNORE;
201 *asp = as;
202 return node;
203 }
204
205 static int is_same_type(struct expression *expr, struct symbol *new)
206 {
207 struct symbol *old = expr->ctype;
208 unsigned long oldmod, newmod, oldas, newas;
209
210 old = base_type(old, &oldmod, &oldas);
211 new = base_type(new, &newmod, &newas);
212
213 /* Same base type, same address space? */
214 if (old == new && oldas == newas) {
215 unsigned long difmod;
216
217 /* Check the modifier bits. */
218 difmod = (oldmod ^ newmod) & ~MOD_NOCAST;
219
220 /* Exact same type? */
221 if (!difmod)
222 return 1;
223
224 /*
225 * Not the same type, but differs only in "const".
226 * Don't warn about MOD_NOCAST.
227 */
228 if (difmod == MOD_CONST)
229 return 0;
230 }
231 if ((oldmod | newmod) & MOD_NOCAST) {
232 const char *tofrom = "to/from";
233 if (!(newmod & MOD_NOCAST))
234 tofrom = "from";
235 if (!(oldmod & MOD_NOCAST))
236 tofrom = "to";
237 warning(expr->pos, "implicit cast %s nocast type", tofrom);
238 }
239 return 0;
240 }
241
242 static void
243 warn_for_different_enum_types (struct position pos,
244 struct symbol *typea,
245 struct symbol *typeb)
246 {
247 if (!Wenum_mismatch)
248 return;
249 if (typea->type == SYM_NODE)
250 typea = typea->ctype.base_type;
251 if (typeb->type == SYM_NODE)
252 typeb = typeb->ctype.base_type;
253
254 if (typea == typeb)
255 return;
256
257 if (typea->type == SYM_ENUM && typeb->type == SYM_ENUM) {
258 warning(pos, "mixing different enum types");
259 info(pos, " %s versus", show_typename(typea));
260 info(pos, " %s", show_typename(typeb));
261 }
262 }
263
264 /*
265 * This gets called for implicit casts in assignments and
266 * integer promotion. We often want to try to move the
267 * cast down, because the ops involved may have been
268 * implicitly cast up, and we can get rid of the casts
269 * early.
270 */
271 static struct expression * cast_to(struct expression *old, struct symbol *type)
272 {
273 struct expression *expr;
274
275 warn_for_different_enum_types (old->pos, old->ctype, type);
276
277 if (is_same_type(old, type))
278 return old;
279
280 /*
281 * See if we can simplify the op. Move the cast down.
282 */
283 switch (old->type) {
284 case EXPR_PREOP:
285 if (old->ctype->bit_size < type->bit_size)
286 break;
287 if (old->op == '~') {
288 old->ctype = type;
289 old->unop = cast_to(old->unop, type);
290 return old;
291 }
292 break;
293
294 case EXPR_IMPLIED_CAST:
295 warn_for_different_enum_types(old->pos, old->ctype, type);
296
297 if (old->ctype->bit_size >= type->bit_size) {
298 struct expression *orig = old->cast_expression;
299 if (same_cast_type(orig->ctype, type))
300 return orig;
301 if (old->ctype->bit_offset == type->bit_offset) {
302 old->ctype = type;
303 old->cast_type = type;
304 return old;
305 }
306 }
307 break;
308
309 default:
310 /* nothing */;
311 }
312
313 expr = alloc_expression(old->pos, EXPR_IMPLIED_CAST);
314 expr->ctype = type;
315 expr->cast_type = type;
316 expr->cast_expression = old;
317 return expr;
318 }
319
320 static int is_type_type(struct symbol *type)
321 {
322 return (type->ctype.modifiers & MOD_TYPE) != 0;
323 }
324
325 int is_ptr_type(struct symbol *type)
326 {
327 if (type->type == SYM_NODE)
328 type = type->ctype.base_type;
329 return type->type == SYM_PTR || type->type == SYM_ARRAY || type->type == SYM_FN;
330 }
331
332 static inline int is_float_type(struct symbol *type)
333 {
334 if (type->type == SYM_NODE)
335 type = type->ctype.base_type;
336 return type->ctype.base_type == &fp_type;
337 }
338
339 static inline int is_byte_type(struct symbol *type)
340 {
341 return type->bit_size == bits_in_char && type->type != SYM_BITFIELD;
342 }
343
344 enum {
345 TYPE_NUM = 1,
346 TYPE_BITFIELD = 2,
347 TYPE_RESTRICT = 4,
348 TYPE_FLOAT = 8,
349 TYPE_PTR = 16,
350 TYPE_COMPOUND = 32,
351 TYPE_FOULED = 64,
352 };
353
354 static inline int classify_type(struct symbol *type, struct symbol **base)
355 {
356 static int type_class[SYM_BAD + 1] = {
357 [SYM_PTR] = TYPE_PTR,
358 [SYM_FN] = TYPE_PTR,
359 [SYM_ARRAY] = TYPE_PTR | TYPE_COMPOUND,
360 [SYM_STRUCT] = TYPE_COMPOUND,
361 [SYM_UNION] = TYPE_COMPOUND,
362 [SYM_BITFIELD] = TYPE_NUM | TYPE_BITFIELD,
363 [SYM_RESTRICT] = TYPE_NUM | TYPE_RESTRICT,
364 [SYM_FOULED] = TYPE_NUM | TYPE_RESTRICT | TYPE_FOULED,
365 };
366 if (type->type == SYM_NODE)
367 type = type->ctype.base_type;
368 if (type->type == SYM_ENUM)
369 type = type->ctype.base_type;
370 *base = type;
371 if (type->type == SYM_BASETYPE) {
372 if (type->ctype.base_type == &int_type)
373 return TYPE_NUM;
374 if (type->ctype.base_type == &fp_type)
375 return TYPE_NUM | TYPE_FLOAT;
376 }
377 return type_class[type->type];
378 }
379
380 static inline int is_string_type(struct symbol *type)
381 {
382 if (type->type == SYM_NODE)
383 type = type->ctype.base_type;
384 return type->type == SYM_ARRAY && is_byte_type(type->ctype.base_type);
385 }
386
387 static struct symbol *bad_expr_type(struct expression *expr)
388 {
389 sparse_error(expr->pos, "incompatible types for operation (%s)", show_special(expr->op));
390 switch (expr->type) {
391 case EXPR_BINOP:
392 case EXPR_COMPARE:
393 info(expr->pos, " left side has type %s", show_typename(expr->left->ctype));
394 info(expr->pos, " right side has type %s", show_typename(expr->right->ctype));
395 break;
396 case EXPR_PREOP:
397 case EXPR_POSTOP:
398 info(expr->pos, " argument has type %s", show_typename(expr->unop->ctype));
399 break;
400 default:
401 break;
402 }
403
404 return expr->ctype = &bad_ctype;
405 }
406
407 static int restricted_value(struct expression *v, struct symbol *type)
408 {
409 if (v->type != EXPR_VALUE)
410 return 1;
411 if (v->value != 0)
412 return 1;
413 return 0;
414 }
415
416 static int restricted_binop(int op, struct symbol *type)
417 {
418 switch (op) {
419 case '&':
420 case '=':
421 case SPECIAL_AND_ASSIGN:
422 case SPECIAL_OR_ASSIGN:
423 case SPECIAL_XOR_ASSIGN:
424 return 1; /* unfoul */
425 case '|':
426 case '^':
427 case '?':
428 return 2; /* keep fouled */
429 case SPECIAL_EQUAL:
430 case SPECIAL_NOTEQUAL:
431 return 3; /* warn if fouled */
432 default:
433 return 0; /* warn */
434 }
435 }
436
437 static int restricted_unop(int op, struct symbol **type)
438 {
439 if (op == '~') {
440 if ((*type)->bit_size < bits_in_int)
441 *type = befoul(*type);
442 return 0;
443 } if (op == '+')
444 return 0;
445 return 1;
446 }
447
448 static struct symbol *restricted_binop_type(int op,
449 struct expression *left,
450 struct expression *right,
451 int lclass, int rclass,
452 struct symbol *ltype,
453 struct symbol *rtype)
454 {
455 struct symbol *ctype = NULL;
456 if (lclass & TYPE_RESTRICT) {
457 if (rclass & TYPE_RESTRICT) {
458 if (ltype == rtype) {
459 ctype = ltype;
460 } else if (lclass & TYPE_FOULED) {
461 if (ltype->ctype.base_type == rtype)
462 ctype = ltype;
463 } else if (rclass & TYPE_FOULED) {
464 if (rtype->ctype.base_type == ltype)
465 ctype = rtype;
466 }
467 } else {
468 if (!restricted_value(right, ltype))
469 ctype = ltype;
470 }
471 } else if (!restricted_value(left, rtype))
472 ctype = rtype;
473
474 if (ctype) {
475 switch (restricted_binop(op, ctype)) {
476 case 1:
477 if ((lclass ^ rclass) & TYPE_FOULED)
478 ctype = ctype->ctype.base_type;
479 break;
480 case 3:
481 if (!(lclass & rclass & TYPE_FOULED))
482 break;
483 case 0:
484 ctype = NULL;
485 default:
486 break;
487 }
488 }
489
490 return ctype;
491 }
492
493 static struct symbol *usual_conversions(int op,
494 struct expression **left,
495 struct expression **right,
496 int lclass, int rclass,
497 struct symbol *ltype,
498 struct symbol *rtype)
499 {
500 struct symbol *ctype;
501
502 warn_for_different_enum_types((*right)->pos, (*left)->ctype, (*right)->ctype);
503
504 if ((lclass | rclass) & TYPE_RESTRICT)
505 goto Restr;
506
507 Normal:
508 if (!(lclass & TYPE_FLOAT)) {
509 if (!(rclass & TYPE_FLOAT))
510 ctype = bigger_int_type(ltype, rtype);
511 else
512 ctype = rtype;
513 } else if (rclass & TYPE_FLOAT) {
514 unsigned long lmod = ltype->ctype.modifiers;
515 unsigned long rmod = rtype->ctype.modifiers;
516 if (rmod & ~lmod & (MOD_LONG | MOD_LONGLONG))
517 ctype = rtype;
518 else
519 ctype = ltype;
520 } else
521 ctype = ltype;
522
523 Convert:
524 *left = cast_to(*left, ctype);
525 *right = cast_to(*right, ctype);
526 return ctype;
527
528 Restr:
529 ctype = restricted_binop_type(op, *left, *right,
530 lclass, rclass, ltype, rtype);
531 if (ctype)
532 goto Convert;
533
534 if (lclass & TYPE_RESTRICT) {
535 warning((*left)->pos, "restricted degrades to integer");
536 ltype = ltype->ctype.base_type;
537 if (is_restricted_type(ltype)) /* was fouled */
538 ltype = ltype->ctype.base_type;
539 }
540 if (rclass & TYPE_RESTRICT) {
541 warning((*right)->pos, "restricted degrades to integer");
542 rtype = rtype->ctype.base_type;
543 if (is_restricted_type(rtype)) /* was fouled */
544 rtype = rtype->ctype.base_type;
545 }
546 goto Normal;
547 }
548
549 static struct symbol *evaluate_arith(struct expression *expr, int float_ok)
550 {
551 struct symbol *ltype, *rtype;
552 int lclass = classify_type(expr->left->ctype, &ltype);
553 int rclass = classify_type(expr->right->ctype, &rtype);
554 struct symbol *ctype;
555
556 if (!(lclass & rclass & TYPE_NUM))
557 goto Bad;
558
559 if (!float_ok && (lclass | rclass) & TYPE_FLOAT)
560 goto Bad;
561
562 ctype = usual_conversions(expr->op, &expr->left, &expr->right,
563 lclass, rclass, ltype, rtype);
564 expr->ctype = ctype;
565 return ctype;
566
567 Bad:
568 return bad_expr_type(expr);
569 }
570
571 static inline int lvalue_expression(struct expression *expr)
572 {
573 return expr->type == EXPR_PREOP && expr->op == '*';
574 }
575
576 static int ptr_object_size(struct symbol *ptr_type)
577 {
578 if (ptr_type->type == SYM_NODE)
579 ptr_type = ptr_type->ctype.base_type;
580 if (ptr_type->type == SYM_PTR)
581 ptr_type = get_base_type(ptr_type);
582 return ptr_type->bit_size;
583 }
584
585 static inline int want_int(struct expression **expr, struct symbol **ctype)
586 {
587 int class = classify_type((*expr)->ctype, ctype);
588
589 if (!(class & TYPE_NUM))
590 return 0;
591 if (!(class & TYPE_RESTRICT))
592 return 1;
593 warning((*expr)->pos, "restricted degrades to integer");
594 if (class & TYPE_FOULED) /* unfoul it first */
595 (*ctype) = (*ctype)->ctype.base_type;
596 (*ctype) = (*ctype)->ctype.base_type; /* get to arithmetic type */
597 *expr = cast_to(*expr, *ctype);
598 return 1;
599 }
600
601 static struct symbol *evaluate_ptr_add(struct expression *expr, struct symbol *ctype, struct expression **ip)
602 {
603 struct expression *i = *ip;
604 struct symbol *ptr_type = ctype, *itype;
605 int bit_size;
606
607 if (ptr_type->type == SYM_NODE)
608 ptr_type = ptr_type->ctype.base_type;
609
610 if (!want_int(&i, &itype))
611 return bad_expr_type(expr);
612
613 examine_symbol_type(ctype);
614
615 if (!ctype->ctype.base_type) {
616 expression_error(expr, "missing type information");
617 return NULL;
618 }
619
620 /* Get the size of whatever the pointer points to */
621 bit_size = ptr_object_size(ctype);
622
623 if (bit_size > bits_in_char) {
624 int multiply = bit_size >> 3;
625 struct expression *val = alloc_expression(expr->pos, EXPR_VALUE);
626
627 if (i->type == EXPR_VALUE) {
628 val->value = i->value * multiply;
629 val->ctype = size_t_ctype;
630 *ip = val;
631 } else {
632 struct expression *mul = alloc_expression(expr->pos, EXPR_BINOP);
633
634 val->ctype = size_t_ctype;
635 val->value = bit_size >> 3;
636
637 mul->op = '*';
638 mul->ctype = size_t_ctype;
639 mul->left = i;
640 mul->right = val;
641
642 *ip = mul;
643 }
644 }
645
646 expr->ctype = ctype;
647 return ctype;
648 }
649
650 static struct symbol *evaluate_add(struct expression *expr)
651 {
652 struct expression *left = expr->left, *right = expr->right;
653 struct symbol *ltype = left->ctype, *rtype = right->ctype;
654
655 if (is_ptr_type(ltype))
656 return evaluate_ptr_add(expr, degenerate(left), &expr->right);
657
658 if (is_ptr_type(rtype))
659 return evaluate_ptr_add(expr, degenerate(right), &expr->left);
660
661 return evaluate_arith(expr, 1);
662 }
663
664 const char * type_difference(struct symbol *target, struct symbol *source,
665 unsigned long target_mod_ignore, unsigned long source_mod_ignore)
666 {
667 for (;;) {
668 unsigned long mod1, mod2, diff;
669 unsigned long as1, as2;
670 int type1, type2;
671 struct symbol *base1, *base2;
672
673 if (target == source)
674 break;
675 if (!target || !source)
676 return "different types";
677 /*
678 * Peel of per-node information.
679 * FIXME! Check alignment and context too here!
680 */
681 mod1 = target->ctype.modifiers;
682 as1 = target->ctype.as;
683 mod2 = source->ctype.modifiers;
684 as2 = source->ctype.as;
685 if (target->type == SYM_NODE) {
686 target = target->ctype.base_type;
687 if (!target)
688 return "bad types";
689 if (target->type == SYM_PTR) {
690 mod1 = 0;
691 as1 = 0;
692 }
693 mod1 |= target->ctype.modifiers;
694 as1 |= target->ctype.as;
695 }
696 if (source->type == SYM_NODE) {
697 source = source->ctype.base_type;
698 if (!source)
699 return "bad types";
700 if (source->type == SYM_PTR) {
701 mod2 = 0;
702 as2 = 0;
703 }
704 mod2 |= source->ctype.modifiers;
705 as2 |= source->ctype.as;
706 }
707 if (target->type == SYM_ENUM) {
708 target = target->ctype.base_type;
709 if (!target)
710 return "bad types";
711 }
712 if (source->type == SYM_ENUM) {
713 source = source->ctype.base_type;
714 if (!source)
715 return "bad types";
716 }
717
718 if (target == source)
719 break;
720 if (!target || !source)
721 return "different types";
722
723 type1 = target->type;
724 base1 = target->ctype.base_type;
725
726 type2 = source->type;
727 base2 = source->ctype.base_type;
728
729 /*
730 * Pointers to functions compare as the function itself
731 */
732 if (type1 == SYM_PTR && base1) {
733 base1 = examine_symbol_type(base1);
734 switch (base1->type) {
735 case SYM_FN:
736 type1 = SYM_FN;
737 target = base1;
738 base1 = base1->ctype.base_type;
739 default:
740 /* nothing */;
741 }
742 }
743 if (type2 == SYM_PTR && base2) {
744 base2 = examine_symbol_type(base2);
745 switch (base2->type) {
746 case SYM_FN:
747 type2 = SYM_FN;
748 source = base2;
749 base2 = base2->ctype.base_type;
750 default:
751 /* nothing */;
752 }
753 }
754
755 /* Arrays degenerate to pointers for type comparisons */
756 type1 = (type1 == SYM_ARRAY) ? SYM_PTR : type1;
757 type2 = (type2 == SYM_ARRAY) ? SYM_PTR : type2;
758
759 if (type1 != type2 || type1 == SYM_RESTRICT)
760 return "different base types";
761
762 /* Must be same address space to be comparable */
763 if (Waddress_space && as1 != as2)
764 return "different address spaces";
765
766 /* Ignore differences in storage types or addressability */
767 diff = (mod1 ^ mod2) & ~MOD_IGNORE;
768 diff &= (mod1 & ~target_mod_ignore) | (mod2 & ~source_mod_ignore);
769 if (diff) {
770 if (diff & MOD_SIZE)
771 return "different type sizes";
772 if (diff & ~MOD_SIGNEDNESS)
773 return "different modifiers";
774
775 /* Differs in signedness only.. */
776 if (Wtypesign) {
777 /*
778 * Warn if both are explicitly signed ("unsigned" is obviously
779 * always explicit, and since we know one of them has to be
780 * unsigned, we check if the signed one was explicit).
781 */
782 if ((mod1 | mod2) & MOD_EXPLICITLY_SIGNED)
783 return "different explicit signedness";
784
785 /*
786 * "char" matches both "unsigned char" and "signed char",
787 * so if the explicit test didn't trigger, then we should
788 * not warn about a char.
789 */
790 if (!(mod1 & MOD_CHAR))
791 return "different signedness";
792 }
793 }
794
795 if (type1 == SYM_FN) {
796 int i;
797 struct symbol *arg1, *arg2;
798 if (base1->variadic != base2->variadic)
799 return "incompatible variadic arguments";
800 PREPARE_PTR_LIST(target->arguments, arg1);
801 PREPARE_PTR_LIST(source->arguments, arg2);
802 i = 1;
803 for (;;) {
804 const char *diffstr;
805 diffstr = type_difference(arg1, arg2, 0, 0);
806 if (diffstr) {
807 static char argdiff[80];
808 sprintf(argdiff, "incompatible argument %d (%s)", i, diffstr);
809 return argdiff;
810 }
811 if (!arg1)
812 break;
813 NEXT_PTR_LIST(arg1);
814 NEXT_PTR_LIST(arg2);
815 i++;
816 }
817 FINISH_PTR_LIST(arg2);
818 FINISH_PTR_LIST(arg1);
819 }
820
821 target = base1;
822 source = base2;
823 }
824 return NULL;
825 }
826
827 static int is_null_ptr(struct expression *expr)
828 {
829 if (expr->type != EXPR_VALUE || expr->value)
830 return 0;
831 if (Wnon_pointer_null && !is_ptr_type(expr->ctype))
832 warning(expr->pos, "Using plain integer as NULL pointer");
833 return 1;
834 }
835
836 static struct symbol *common_ptr_type(struct expression *l, struct expression *r)
837 {
838 /* NULL expression? Just return the type of the "other side" */
839 if (is_null_ptr(r))
840 return l->ctype;
841 if (is_null_ptr(l))
842 return r->ctype;
843 return NULL;
844 }
845
846 /*
847 * Ignore differences in "volatile" and "const"ness when
848 * subtracting pointers
849 */
850 #define MOD_IGN (MOD_VOLATILE | MOD_CONST)
851
852 static struct symbol *evaluate_ptr_sub(struct expression *expr, struct expression *l, struct expression **rp)
853 {
854 const char *typediff;
855 struct symbol *ctype;
856 struct symbol *ltype, *rtype;
857 struct expression *r = *rp;
858
859 ltype = degenerate(l);
860 rtype = degenerate(r);
861
862 /*
863 * If it is an integer subtract: the ptr add case will do the
864 * right thing.
865 */
866 if (!is_ptr_type(rtype))
867 return evaluate_ptr_add(expr, degenerate(l), rp);
868
869 ctype = ltype;
870 typediff = type_difference(ltype, rtype, ~MOD_SIZE, ~MOD_SIZE);
871 if (typediff) {
872 ctype = common_ptr_type(l, r);
873 if (!ctype) {
874 expression_error(expr, "subtraction of different types can't work (%s)", typediff);
875 return NULL;
876 }
877 }
878 examine_symbol_type(ctype);
879
880 /* Figure out the base type we point to */
881 if (ctype->type == SYM_NODE)
882 ctype = ctype->ctype.base_type;
883 if (ctype->type != SYM_PTR && ctype->type != SYM_ARRAY) {
884 expression_error(expr, "subtraction of functions? Share your drugs");
885 return NULL;
886 }
887 ctype = get_base_type(ctype);
888
889 expr->ctype = ssize_t_ctype;
890 if (ctype->bit_size > bits_in_char) {
891 struct expression *sub = alloc_expression(expr->pos, EXPR_BINOP);
892 struct expression *div = expr;
893 struct expression *val = alloc_expression(expr->pos, EXPR_VALUE);
894 unsigned long value = ctype->bit_size >> 3;
895
896 val->ctype = size_t_ctype;
897 val->value = value;
898
899 if (value & (value-1)) {
900 if (Wptr_subtraction_blows)
901 warning(expr->pos, "potentially expensive pointer subtraction");
902 }
903
904 sub->op = '-';
905 sub->ctype = ssize_t_ctype;
906 sub->left = l;
907 sub->right = r;
908
909 div->op = '/';
910 div->left = sub;
911 div->right = val;
912 }
913
914 return ssize_t_ctype;
915 }
916
917 static struct symbol *evaluate_sub(struct expression *expr)
918 {
919 struct expression *left = expr->left;
920 struct symbol *ltype = left->ctype;
921
922 if (is_ptr_type(ltype))
923 return evaluate_ptr_sub(expr, left, &expr->right);
924
925 return evaluate_arith(expr, 1);
926 }
927
928 #define is_safe_type(type) ((type)->ctype.modifiers & MOD_SAFE)
929
930 static struct symbol *evaluate_conditional(struct expression *expr, int iterator)
931 {
932 struct symbol *ctype;
933
934 if (!expr)
935 return NULL;
936
937 if (!iterator && expr->type == EXPR_ASSIGNMENT && expr->op == '=')
938 warning(expr->pos, "assignment expression in conditional");
939
940 ctype = evaluate_expression(expr);
941 if (ctype) {
942 if (is_safe_type(ctype))
943 warning(expr->pos, "testing a 'safe expression'");
944 }
945
946 return ctype;
947 }
948
949 static struct symbol *evaluate_logical(struct expression *expr)
950 {
951 if (!evaluate_conditional(expr->left, 0))
952 return NULL;
953 if (!evaluate_conditional(expr->right, 0))
954 return NULL;
955
956 expr->ctype = &bool_ctype;
957 return &bool_ctype;
958 }
959
960 static struct symbol *evaluate_shift(struct expression *expr)
961 {
962 struct symbol *ltype, *rtype;
963
964 if (want_int(&expr->left, &ltype) && want_int(&expr->right, &rtype)) {
965 struct symbol *ctype = integer_promotion(ltype);
966 expr->left = cast_to(expr->left, ctype);
967 expr->ctype = ctype;
968 ctype = integer_promotion(rtype);
969 expr->right = cast_to(expr->right, ctype);
970 return expr->ctype;
971 }
972 return bad_expr_type(expr);
973 }
974
975 static struct symbol *evaluate_binop(struct expression *expr)
976 {
977 switch (expr->op) {
978 // addition can take ptr+int, fp and int
979 case '+':
980 return evaluate_add(expr);
981
982 // subtraction can take ptr-ptr, fp and int
983 case '-':
984 return evaluate_sub(expr);
985
986 // Arithmetic operations can take fp and int
987 case '*': case '/':
988 return evaluate_arith(expr, 1);
989
990 // shifts do integer promotions, but that's it.
991 case SPECIAL_LEFTSHIFT: case SPECIAL_RIGHTSHIFT:
992 return evaluate_shift(expr);
993
994 // The rest are integer operations
995 // '%', '&', '^', '|'
996 default:
997 return evaluate_arith(expr, 0);
998 }
999 }
1000
1001 static struct symbol *evaluate_comma(struct expression *expr)
1002 {
1003 expr->ctype = expr->right->ctype;
1004 return expr->ctype;
1005 }
1006
1007 static int modify_for_unsigned(int op)
1008 {
1009 if (op == '<')
1010 op = SPECIAL_UNSIGNED_LT;
1011 else if (op == '>')
1012 op = SPECIAL_UNSIGNED_GT;
1013 else if (op == SPECIAL_LTE)
1014 op = SPECIAL_UNSIGNED_LTE;
1015 else if (op == SPECIAL_GTE)
1016 op = SPECIAL_UNSIGNED_GTE;
1017 return op;
1018 }
1019
1020 static struct symbol *evaluate_compare(struct expression *expr)
1021 {
1022 struct expression *left = expr->left, *right = expr->right;
1023 struct symbol *ltype = left->ctype, *rtype = right->ctype;
1024 struct symbol *ctype;
1025
1026 /* Type types? */
1027 if (is_type_type(ltype) && is_type_type(rtype))
1028 goto OK;
1029
1030 if (is_safe_type(ltype) || is_safe_type(rtype))
1031 warning(expr->pos, "testing a 'safe expression'");
1032
1033 /* Pointer types? */
1034 if (is_ptr_type(ltype) || is_ptr_type(rtype)) {
1035 // FIXME! Check the types for compatibility
1036 expr->op = modify_for_unsigned(expr->op);
1037 goto OK;
1038 }
1039
1040 ctype = evaluate_arith(expr, 1);
1041 if (ctype) {
1042 if (ctype->ctype.modifiers & MOD_UNSIGNED)
1043 expr->op = modify_for_unsigned(expr->op);
1044 }
1045 OK:
1046 expr->ctype = &bool_ctype;
1047 return &bool_ctype;
1048 }
1049
1050 /*
1051 * FIXME!! This should do casts, array degeneration etc..
1052 */
1053 static struct symbol *compatible_ptr_type(struct expression *left, struct expression *right)
1054 {
1055 struct symbol *ltype = left->ctype, *rtype = right->ctype;
1056
1057 if (ltype->type == SYM_NODE)
1058 ltype = ltype->ctype.base_type;
1059
1060 if (rtype->type == SYM_NODE)
1061 rtype = rtype->ctype.base_type;
1062
1063 if (ltype->type == SYM_PTR) {
1064 if (is_null_ptr(right) || rtype->ctype.base_type == &void_ctype)
1065 return ltype;
1066 }
1067
1068 if (rtype->type == SYM_PTR) {
1069 if (is_null_ptr(left) || ltype->ctype.base_type == &void_ctype)
1070 return rtype;
1071 }
1072 return NULL;
1073 }
1074
1075 /*
1076 * NOTE! The degenerate case of "x ? : y", where we don't
1077 * have a true case, this will possibly promote "x" to the
1078 * same type as "y", and thus _change_ the conditional
1079 * test in the expression. But since promotion is "safe"
1080 * for testing, that's OK.
1081 */
1082 static struct symbol *evaluate_conditional_expression(struct expression *expr)
1083 {
1084 struct expression **true;
1085 struct symbol *ctype, *ltype, *rtype;
1086 int lclass, rclass;
1087 const char * typediff;
1088
1089 if (!evaluate_conditional(expr->conditional, 0))
1090 return NULL;
1091 if (!evaluate_expression(expr->cond_false))
1092 return NULL;
1093
1094 ctype = degenerate(expr->conditional);
1095 rtype = degenerate(expr->cond_false);
1096
1097 true = &expr->conditional;
1098 ltype = ctype;
1099 if (expr->cond_true) {
1100 if (!evaluate_expression(expr->cond_true))
1101 return NULL;
1102 ltype = degenerate(expr->cond_true);
1103 true = &expr->cond_true;
1104 }
1105
1106 lclass = classify_type(ltype, &ltype);
1107 rclass = classify_type(rtype, &rtype);
1108 if (lclass & rclass & TYPE_NUM) {
1109 ctype = usual_conversions('?', true, &expr->cond_false,
1110 lclass, rclass, ltype, rtype);
1111 goto out;
1112 }
1113 ctype = compatible_ptr_type(*true, expr->cond_false);
1114 if (ctype)
1115 goto out;
1116 ctype = ltype;
1117 typediff = type_difference(ltype, rtype, MOD_IGN, MOD_IGN);
1118 if (!typediff)
1119 goto out;
1120 expression_error(expr, "incompatible types in conditional expression (%s)", typediff);
1121 return NULL;
1122
1123 out:
1124 expr->ctype = ctype;
1125 return ctype;
1126 }
1127
1128 /* FP assignments can not do modulo or bit operations */
1129 static int compatible_float_op(int op)
1130 {
1131 return op == '=' ||
1132 op == SPECIAL_ADD_ASSIGN ||
1133 op == SPECIAL_SUB_ASSIGN ||
1134 op == SPECIAL_MUL_ASSIGN ||
1135 op == SPECIAL_DIV_ASSIGN;
1136 }
1137
1138 static int compatible_assignment_types(struct expression *expr, struct symbol *target,
1139 struct expression **rp, struct symbol *source, const char *where, int op)
1140 {
1141 const char *typediff;
1142 struct symbol *t, *s;
1143 int target_as;
1144 int tclass = classify_type(target, &t);
1145 int sclass = classify_type(source, &s);
1146
1147 if (tclass & sclass & TYPE_NUM) {
1148 if (tclass & TYPE_FLOAT && !compatible_float_op(op)) {
1149 expression_error(expr, "invalid assignment");
1150 return 0;
1151 }
1152 if (tclass & TYPE_RESTRICT) {
1153 if (!restricted_binop(op, target)) {
1154 expression_error(expr, "bad restricted assignment");
1155 return 0;
1156 }
1157 /* allowed assignments unfoul */
1158 if (sclass & TYPE_FOULED && s->ctype.base_type == t)
1159 goto Cast;
1160 if (!restricted_value(*rp, target))
1161 return 1;
1162 } else if (!(sclass & TYPE_RESTRICT))
1163 goto Cast;
1164 } else if (tclass & TYPE_PTR) {
1165 if (op == SPECIAL_ADD_ASSIGN || op == SPECIAL_SUB_ASSIGN) {
1166 evaluate_ptr_add(expr, target, rp);
1167 return 1;
1168 }
1169 if (op != '=') {
1170 expression_error(expr, "invalid pointer assignment");
1171 return 0;
1172 }
1173 } else if (op != '=') {
1174 expression_error(expr, "invalid assignment");
1175 return 0;
1176 }
1177
1178 /* It's OK if the target is more volatile or const than the source */
1179 typediff = type_difference(target, source, MOD_VOLATILE | MOD_CONST, 0);
1180 if (!typediff)
1181 return 1;
1182
1183 /* Pointer destination? */
1184 if (tclass & TYPE_PTR) {
1185 struct expression *right = *rp;
1186 int source_as;
1187
1188 // NULL pointer is always OK
1189 if (is_null_ptr(right))
1190 goto Cast;
1191
1192 /* "void *" matches anything as long as the address space is OK */
1193 target_as = t->ctype.as | target->ctype.as;
1194 source_as = s->ctype.as | source->ctype.as;
1195 if (source_as == target_as && (s->type == SYM_PTR || s->type == SYM_ARRAY)) {
1196 s = get_base_type(s);
1197 t = get_base_type(t);
1198 if (s == &void_ctype || t == &void_ctype)
1199 goto Cast;
1200 }
1201 }
1202
1203 warning(expr->pos, "incorrect type in %s (%s)", where, typediff);
1204 info(expr->pos, " expected %s", show_typename(target));
1205 info(expr->pos, " got %s", show_typename(source));
1206 *rp = cast_to(*rp, target);
1207 return 0;
1208 Cast:
1209 *rp = cast_to(*rp, target);
1210 return 1;
1211 }
1212
1213 static void mark_assigned(struct expression *expr)
1214 {
1215 struct symbol *sym;
1216
1217 if (!expr)
1218 return;
1219 switch (expr->type) {
1220 case EXPR_SYMBOL:
1221 sym = expr->symbol;
1222 if (!sym)
1223 return;
1224 if (sym->type != SYM_NODE)
1225 return;
1226 sym->ctype.modifiers |= MOD_ASSIGNED;
1227 return;
1228
1229 case EXPR_BINOP:
1230 mark_assigned(expr->left);
1231 mark_assigned(expr->right);
1232 return;
1233 case EXPR_CAST:
1234 mark_assigned(expr->cast_expression);
1235 return;
1236 case EXPR_SLICE:
1237 mark_assigned(expr->base);
1238 return;
1239 default:
1240 /* Hmm? */
1241 return;
1242 }
1243 }
1244
1245 static void evaluate_assign_to(struct expression *left, struct symbol *type)
1246 {
1247 if (type->ctype.modifiers & MOD_CONST)
1248 expression_error(left, "assignment to const expression");
1249
1250 /* We know left is an lvalue, so it's a "preop-*" */
1251 mark_assigned(left->unop);
1252 }
1253
1254 static struct symbol *evaluate_assignment(struct expression *expr)
1255 {
1256 struct expression *left = expr->left, *right = expr->right;
1257 struct expression *where = expr;
1258 struct symbol *ltype, *rtype;
1259
1260 if (!lvalue_expression(left)) {
1261 expression_error(expr, "not an lvalue");
1262 return NULL;
1263 }
1264
1265 ltype = left->ctype;
1266
1267 rtype = degenerate(right);
1268
1269 if (!compatible_assignment_types(where, ltype, &where->right, rtype, "assignment", expr->op))
1270 return NULL;
1271
1272 evaluate_assign_to(left, ltype);
1273
1274 expr->ctype = ltype;
1275 return ltype;
1276 }
1277
1278 static void examine_fn_arguments(struct symbol *fn)
1279 {
1280 struct symbol *s;
1281
1282 FOR_EACH_PTR(fn->arguments, s) {
1283 struct symbol *arg = evaluate_symbol(s);
1284 /* Array/function arguments silently degenerate into pointers */
1285 if (arg) {
1286 struct symbol *ptr;
1287 switch(arg->type) {
1288 case SYM_ARRAY:
1289 case SYM_FN:
1290 ptr = alloc_symbol(s->pos, SYM_PTR);
1291 if (arg->type == SYM_ARRAY)
1292 ptr->ctype = arg->ctype;
1293 else
1294 ptr->ctype.base_type = arg;
1295 ptr->ctype.as |= s->ctype.as;
1296 ptr->ctype.modifiers |= s->ctype.modifiers & MOD_PTRINHERIT;
1297
1298 s->ctype.base_type = ptr;
1299 s->ctype.as = 0;
1300 s->ctype.modifiers &= ~MOD_PTRINHERIT;
1301 s->bit_size = 0;
1302 s->examined = 0;
1303 examine_symbol_type(s);
1304 break;
1305 default:
1306 /* nothing */
1307 break;
1308 }
1309 }
1310 } END_FOR_EACH_PTR(s);
1311 }
1312
1313 static struct symbol *convert_to_as_mod(struct symbol *sym, int as, int mod)
1314 {
1315 /* Take the modifiers of the pointer, and apply them to the member */
1316 mod |= sym->ctype.modifiers;
1317 if (sym->ctype.as != as || sym->ctype.modifiers != mod) {
1318 struct symbol *newsym = alloc_symbol(sym->pos, SYM_NODE);
1319 *newsym = *sym;
1320 newsym->ctype.as = as;
1321 newsym->ctype.modifiers = mod;
1322 sym = newsym;
1323 }
1324 return sym;
1325 }
1326
1327 static struct symbol *create_pointer(struct expression *expr, struct symbol *sym, int degenerate)
1328 {
1329 struct symbol *node = alloc_symbol(expr->pos, SYM_NODE);
1330 struct symbol *ptr = alloc_symbol(expr->pos, SYM_PTR);
1331
1332 node->ctype.base_type = ptr;
1333 ptr->bit_size = bits_in_pointer;
1334 ptr->ctype.alignment = pointer_alignment;
1335
1336 node->bit_size = bits_in_pointer;
1337 node->ctype.alignment = pointer_alignment;
1338
1339 access_symbol(sym);
1340 if (sym->ctype.modifiers & MOD_REGISTER) {
1341 warning(expr->pos, "taking address of 'register' variable '%s'", show_ident(sym->ident));
1342 sym->ctype.modifiers &= ~MOD_REGISTER;
1343 }
1344 if (sym->type == SYM_NODE) {
1345 ptr->ctype.as |= sym->ctype.as;
1346 ptr->ctype.modifiers |= sym->ctype.modifiers & MOD_PTRINHERIT;
1347 sym = sym->ctype.base_type;
1348 }
1349 if (degenerate && sym->type == SYM_ARRAY) {
1350 ptr->ctype.as |= sym->ctype.as;
1351 ptr->ctype.modifiers |= sym->ctype.modifiers & MOD_PTRINHERIT;
1352 sym = sym->ctype.base_type;
1353 }
1354 ptr->ctype.base_type = sym;
1355
1356 return node;
1357 }
1358
1359 /* Arrays degenerate into pointers on pointer arithmetic */
1360 static struct symbol *degenerate(struct expression *expr)
1361 {
1362 struct symbol *ctype, *base;
1363
1364 if (!expr)
1365 return NULL;
1366 ctype = expr->ctype;
1367 if (!ctype)
1368 return NULL;
1369 base = examine_symbol_type(ctype);
1370 if (ctype->type == SYM_NODE)
1371 base = ctype->ctype.base_type;
1372 /*
1373 * Arrays degenerate into pointers to the entries, while
1374 * functions degenerate into pointers to themselves.
1375 * If array was part of non-lvalue compound, we create a copy
1376 * of that compound first and then act as if we were dealing with
1377 * the corresponding field in there.
1378 */
1379 switch (base->type) {
1380 case SYM_ARRAY:
1381 if (expr->type == EXPR_SLICE) {
1382 struct symbol *a = alloc_symbol(expr->pos, SYM_NODE);
1383 struct expression *e0, *e1, *e2, *e3, *e4;
1384
1385 a->ctype.base_type = expr->base->ctype;
1386 a->bit_size = expr->base->ctype->bit_size;
1387 a->array_size = expr->base->ctype->array_size;
1388
1389 e0 = alloc_expression(expr->pos, EXPR_SYMBOL);
1390 e0->symbol = a;
1391 e0->ctype = &lazy_ptr_ctype;
1392
1393 e1 = alloc_expression(expr->pos, EXPR_PREOP);
1394 e1->unop = e0;
1395 e1->op = '*';
1396 e1->ctype = expr->base->ctype; /* XXX */
1397
1398 e2 = alloc_expression(expr->pos, EXPR_ASSIGNMENT);
1399 e2->left = e1;
1400 e2->right = expr->base;
1401 e2->op = '=';
1402 e2->ctype = expr->base->ctype;
1403
1404 if (expr->r_bitpos) {
1405 e3 = alloc_expression(expr->pos, EXPR_BINOP);
1406 e3->op = '+';
1407 e3->left = e0;
1408 e3->right = alloc_const_expression(expr->pos,
1409 expr->r_bitpos >> 3);
1410 e3->ctype = &lazy_ptr_ctype;
1411 } else {
1412 e3 = e0;
1413 }
1414
1415 e4 = alloc_expression(expr->pos, EXPR_COMMA);
1416 e4->left = e2;
1417 e4->right = e3;
1418 e4->ctype = &lazy_ptr_ctype;
1419
1420 expr->unop = e4;
1421 expr->type = EXPR_PREOP;
1422 expr->op = '*';
1423 }
1424 case SYM_FN:
1425 if (expr->op != '*' || expr->type != EXPR_PREOP) {
1426 expression_error(expr, "strange non-value function or array");
1427 return &bad_ctype;
1428 }
1429 *expr = *expr->unop;
1430 ctype = create_pointer(expr, ctype, 1);
1431 expr->ctype = ctype;
1432 default:
1433 /* nothing */;
1434 }
1435 return ctype;
1436 }
1437
1438 static struct symbol *evaluate_addressof(struct expression *expr)
1439 {
1440 struct expression *op = expr->unop;
1441 struct symbol *ctype;
1442
1443 if (op->op != '*' || op->type != EXPR_PREOP) {
1444 expression_error(expr, "not addressable");
1445 return NULL;
1446 }
1447 ctype = op->ctype;
1448 *expr = *op->unop;
1449
1450 if (expr->type == EXPR_SYMBOL) {
1451 struct symbol *sym = expr->symbol;
1452 sym->ctype.modifiers |= MOD_ADDRESSABLE;
1453 }
1454
1455 /*
1456 * symbol expression evaluation is lazy about the type
1457 * of the sub-expression, so we may have to generate
1458 * the type here if so..
1459 */
1460 if (expr->ctype == &lazy_ptr_ctype) {
1461 ctype = create_pointer(expr, ctype, 0);
1462 expr->ctype = ctype;
1463 }
1464 return expr->ctype;
1465 }
1466
1467
1468 static struct symbol *evaluate_dereference(struct expression *expr)
1469 {
1470 struct expression *op = expr->unop;
1471 struct symbol *ctype = op->ctype, *node, *target;
1472
1473 /* Simplify: *&(expr) => (expr) */
1474 if (op->type == EXPR_PREOP && op->op == '&') {
1475 *expr = *op->unop;
1476 return expr->ctype;
1477 }
1478
1479 /* Dereferencing a node drops all the node information. */
1480 if (ctype->type == SYM_NODE)
1481 ctype = ctype->ctype.base_type;
1482
1483 node = alloc_symbol(expr->pos, SYM_NODE);
1484 target = ctype->ctype.base_type;
1485
1486 switch (ctype->type) {
1487 default:
1488 expression_error(expr, "cannot dereference this type");
1489 return NULL;
1490 case SYM_PTR:
1491 node->ctype.modifiers = target->ctype.modifiers & MOD_SPECIFIER;
1492 merge_type(node, ctype);
1493 break;
1494
1495 case SYM_ARRAY:
1496 if (!lvalue_expression(op)) {
1497 expression_error(op, "non-lvalue array??");
1498 return NULL;
1499 }
1500
1501 /* Do the implied "addressof" on the array */
1502 *op = *op->unop;
1503
1504 /*
1505 * When an array is dereferenced, we need to pick
1506 * up the attributes of the original node too..
1507 */
1508 merge_type(node, op->ctype);
1509 merge_type(node, ctype);
1510 break;
1511 }
1512
1513 node->bit_size = target->bit_size;
1514 node->array_size = target->array_size;
1515
1516 expr->ctype = node;
1517 return node;
1518 }
1519
1520 /*
1521 * Unary post-ops: x++ and x--
1522 */
1523 static struct symbol *evaluate_postop(struct expression *expr)
1524 {
1525 struct expression *op = expr->unop;
1526 struct symbol *ctype = op->ctype;
1527
1528 if (!lvalue_expression(expr->unop)) {
1529 expression_error(expr, "need lvalue expression for ++/--");
1530 return NULL;
1531 }
1532 if (is_restricted_type(ctype) && restricted_unop(expr->op, &ctype)) {
1533 expression_error(expr, "bad operation on restricted");
1534 return NULL;
1535 } else if (is_fouled_type(ctype) && restricted_unop(expr->op, &ctype)) {
1536 expression_error(expr, "bad operation on restricted");
1537 return NULL;
1538 }
1539
1540 evaluate_assign_to(op, ctype);
1541
1542 expr->ctype = ctype;
1543 expr->op_value = 1;
1544 if (is_ptr_type(ctype))
1545 expr->op_value = ptr_object_size(ctype) >> 3;
1546
1547 return ctype;
1548 }
1549
1550 static struct symbol *evaluate_sign(struct expression *expr)
1551 {
1552 struct symbol *ctype = expr->unop->ctype;
1553 if (is_int_type(ctype)) {
1554 struct symbol *rtype = rtype = integer_promotion(ctype);
1555 expr->unop = cast_to(expr->unop, rtype);
1556 ctype = rtype;
1557 } else if (is_float_type(ctype) && expr->op != '~') {
1558 /* no conversions needed */
1559 } else if (is_restricted_type(ctype) && !restricted_unop(expr->op, &ctype)) {
1560 /* no conversions needed */
1561 } else if (is_fouled_type(ctype) && !restricted_unop(expr->op, &ctype)) {
1562 /* no conversions needed */
1563 } else {
1564 return bad_expr_type(expr);
1565 }
1566 if (expr->op == '+')
1567 *expr = *expr->unop;
1568 expr->ctype = ctype;
1569 return ctype;
1570 }
1571
1572 static struct symbol *evaluate_preop(struct expression *expr)
1573 {
1574 struct symbol *ctype = expr->unop->ctype;
1575
1576 switch (expr->op) {
1577 case '(':
1578 *expr = *expr->unop;
1579 return ctype;
1580
1581 case '+':
1582 case '-':
1583 case '~':
1584 return evaluate_sign(expr);
1585
1586 case '*':
1587 return evaluate_dereference(expr);
1588
1589 case '&':
1590 return evaluate_addressof(expr);
1591
1592 case SPECIAL_INCREMENT:
1593 case SPECIAL_DECREMENT:
1594 /*
1595 * From a type evaluation standpoint the preops are
1596 * the same as the postops
1597 */
1598 return evaluate_postop(expr);
1599
1600 case '!':
1601 if (is_safe_type(ctype))
1602 warning(expr->pos, "testing a 'safe expression'");
1603 if (is_float_type(ctype)) {
1604 struct expression *arg = expr->unop;
1605 expr->type = EXPR_BINOP;
1606 expr->op = SPECIAL_EQUAL;
1607 expr->left = arg;
1608 expr->right = alloc_expression(expr->pos, EXPR_FVALUE);
1609 expr->right->ctype = ctype;
1610 expr->right->fvalue = 0;
1611 } else if (is_fouled_type(ctype)) {
1612 warning(expr->pos, "restricted degrades to integer");
1613 }
1614 ctype = &bool_ctype;
1615 break;
1616
1617 default:
1618 break;
1619 }
1620 expr->ctype = ctype;
1621 return &bool_ctype;
1622 }
1623
1624 static struct symbol *find_identifier(struct ident *ident, struct symbol_list *_list, int *offset)
1625 {
1626 struct ptr_list *head = (struct ptr_list *)_list;
1627 struct ptr_list *list = head;
1628
1629 if (!head)
1630 return NULL;
1631 do {
1632 int i;
1633 for (i = 0; i < list->nr; i++) {
1634 struct symbol *sym = (struct symbol *) list->list[i];
1635 if (sym->ident) {
1636 if (sym->ident != ident)
1637 continue;
1638 *offset = sym->offset;
1639 return sym;
1640 } else {
1641 struct symbol *ctype = sym->ctype.base_type;
1642 struct symbol *sub;
1643 if (!ctype)
1644 continue;
1645 if (ctype->type != SYM_UNION && ctype->type != SYM_STRUCT)
1646 continue;
1647 sub = find_identifier(ident, ctype->symbol_list, offset);
1648 if (!sub)
1649 continue;
1650 *offset += sym->offset;
1651 return sub;
1652 }
1653 }
1654 } while ((list = list->next) != head);
1655 return NULL;
1656 }
1657
1658 static struct expression *evaluate_offset(struct expression *expr, unsigned long offset)
1659 {
1660 struct expression *add;
1661
1662 /*
1663 * Create a new add-expression
1664 *
1665 * NOTE! Even if we just add zero, we need a new node
1666 * for the member pointer, since it has a different
1667 * type than the original pointer. We could make that
1668 * be just a cast, but the fact is, a node is a node,
1669 * so we might as well just do the "add zero" here.
1670 */
1671 add = alloc_expression(expr->pos, EXPR_BINOP);
1672 add->op = '+';
1673 add->left = expr;
1674 add->right = alloc_expression(expr->pos, EXPR_VALUE);
1675 add->right->ctype = &int_ctype;
1676 add->right->value = offset;
1677
1678 /*
1679 * The ctype of the pointer will be lazily evaluated if
1680 * we ever take the address of this member dereference..
1681 */
1682 add->ctype = &lazy_ptr_ctype;
1683 return add;
1684 }
1685
1686 /* structure/union dereference */
1687 static struct symbol *evaluate_member_dereference(struct expression *expr)
1688 {
1689 int offset;
1690 struct symbol *ctype, *member;
1691 struct expression *deref = expr->deref, *add;
1692 struct ident *ident = expr->member;
1693 unsigned int mod;
1694 int address_space;
1695
1696 if (!evaluate_expression(deref))
1697 return NULL;
1698 if (!ident) {
1699 expression_error(expr, "bad member name");
1700 return NULL;
1701 }
1702
1703 ctype = deref->ctype;
1704 address_space = ctype->ctype.as;
1705 mod = ctype->ctype.modifiers;
1706 if (ctype->type == SYM_NODE) {
1707 ctype = ctype->ctype.base_type;
1708 address_space |= ctype->ctype.as;
1709 mod |= ctype->ctype.modifiers;
1710 }
1711 if (!ctype || (ctype->type != SYM_STRUCT && ctype->type != SYM_UNION)) {
1712 expression_error(expr, "expected structure or union");
1713 return NULL;
1714 }
1715 examine_symbol_type(ctype);
1716 offset = 0;
1717 member = find_identifier(ident, ctype->symbol_list, &offset);
1718 if (!member) {
1719 const char *type = ctype->type == SYM_STRUCT ? "struct" : "union";
1720 const char *name = "<unnamed>";
1721 int namelen = 9;
1722 if (ctype->ident) {
1723 name = ctype->ident->name;
1724 namelen = ctype->ident->len;
1725 }
1726 if (ctype->symbol_list)
1727 expression_error(expr, "no member '%s' in %s %.*s",
1728 show_ident(ident), type, namelen, name);
1729 else
1730 expression_error(expr, "using member '%s' in "
1731 "incomplete %s %.*s", show_ident(ident),
1732 type, namelen, name);
1733 return NULL;
1734 }
1735
1736 /*
1737 * The member needs to take on the address space and modifiers of
1738 * the "parent" type.
1739 */
1740 member = convert_to_as_mod(member, address_space, mod);
1741 ctype = get_base_type(member);
1742
1743 if (!lvalue_expression(deref)) {
1744 if (deref->type != EXPR_SLICE) {
1745 expr->base = deref;
1746 expr->r_bitpos = 0;
1747 } else {
1748 expr->base = deref->base;
1749 expr->r_bitpos = deref->r_bitpos;
1750 }
1751 expr->r_bitpos += offset << 3;
1752 expr->type = EXPR_SLICE;
1753 expr->r_nrbits = member->bit_size;
1754 expr->r_bitpos += member->bit_offset;
1755 expr->ctype = member;
1756 return member;
1757 }
1758
1759 deref = deref->unop;
1760 expr->deref = deref;
1761
1762 add = evaluate_offset(deref, offset);
1763 expr->type = EXPR_PREOP;
1764 expr->op = '*';
1765 expr->unop = add;
1766
1767 expr->ctype = member;
1768 return member;
1769 }
1770
1771 static int is_promoted(struct expression *expr)
1772 {
1773 while (1) {
1774 switch (expr->type) {
1775 case EXPR_BINOP:
1776 case EXPR_SELECT:
1777 case EXPR_CONDITIONAL:
1778 return 1;
1779 case EXPR_COMMA:
1780 expr = expr->right;
1781 continue;
1782 case EXPR_PREOP:
1783 switch (expr->op) {
1784 case '(':
1785 expr = expr->unop;
1786 continue;
1787 case '+':
1788 case '-':
1789 case '~':
1790 return 1;
1791 default:
1792 return 0;
1793 }
1794 default:
1795 return 0;
1796 }
1797 }
1798 }
1799
1800
1801 static struct symbol *evaluate_cast(struct expression *);
1802
1803 static struct symbol *evaluate_type_information(struct expression *expr)
1804 {
1805 struct symbol *sym = expr->cast_type;
1806 if (!sym) {
1807 sym = evaluate_expression(expr->cast_expression);
1808 if (!sym)
1809 return NULL;
1810 /*
1811 * Expressions of restricted types will possibly get
1812 * promoted - check that here
1813 */
1814 if (is_restricted_type(sym)) {
1815 if (sym->bit_size < bits_in_int && is_promoted(expr))
1816 sym = &int_ctype;
1817 } else if (is_fouled_type(sym)) {
1818 sym = &int_ctype;
1819 }
1820 }
1821 examine_symbol_type(sym);
1822 if (is_bitfield_type(sym)) {
1823 expression_error(expr, "trying to examine bitfield type");
1824 return NULL;
1825 }
1826 return sym;
1827 }
1828
1829 static struct symbol *evaluate_sizeof(struct expression *expr)
1830 {
1831 struct symbol *type;
1832 int size;
1833
1834 type = evaluate_type_information(expr);
1835 if (!type)
1836 return NULL;
1837
1838 size = type->bit_size;
1839 if ((size < 0) || (size & 7))
1840 expression_error(expr, "cannot size expression");
1841 expr->type = EXPR_VALUE;
1842 expr->value = size >> 3;
1843 expr->ctype = size_t_ctype;
1844 return size_t_ctype;
1845 }
1846
1847 static struct symbol *evaluate_ptrsizeof(struct expression *expr)
1848 {
1849 struct symbol *type;
1850 int size;
1851
1852 type = evaluate_type_information(expr);
1853 if (!type)
1854 return NULL;
1855
1856 if (type->type == SYM_NODE)
1857 type = type->ctype.base_type;
1858 if (!type)
1859 return NULL;
1860 switch (type->type) {
1861 case SYM_ARRAY:
1862 break;
1863 case SYM_PTR:
1864 type = get_base_type(type);
1865 if (type)
1866 break;
1867 default:
1868 expression_error(expr, "expected pointer expression");
1869 return NULL;
1870 }
1871 size = type->bit_size;
1872 if (size & 7)
1873 size = 0;
1874 expr->type = EXPR_VALUE;
1875 expr->value = size >> 3;
1876 expr->ctype = size_t_ctype;
1877 return size_t_ctype;
1878 }
1879
1880 static struct symbol *evaluate_alignof(struct expression *expr)
1881 {
1882 struct symbol *type;
1883
1884 type = evaluate_type_information(expr);
1885 if (!type)
1886 return NULL;
1887
1888 expr->type = EXPR_VALUE;
1889 expr->value = type->ctype.alignment;
1890 expr->ctype = size_t_ctype;
1891 return size_t_ctype;
1892 }
1893
1894 static int evaluate_arguments(struct symbol *f, struct symbol *fn, struct expression_list *head)
1895 {
1896 struct expression *expr;
1897 struct symbol_list *argument_types = fn->arguments;
1898 struct symbol *argtype;
1899 int i = 1;
1900
1901 PREPARE_PTR_LIST(argument_types, argtype);
1902 FOR_EACH_PTR (head, expr) {
1903 struct expression **p = THIS_ADDRESS(expr);
1904 struct symbol *ctype, *target;
1905 ctype = evaluate_expression(expr);
1906
1907 if (!ctype)
1908 return 0;
1909
1910 ctype = degenerate(expr);
1911
1912 target = argtype;
1913 if (!target && ctype->bit_size < bits_in_int)
1914 target = &int_ctype;
1915 if (target) {
1916 static char where[30];
1917 examine_symbol_type(target);
1918 sprintf(where, "argument %d", i);
1919 compatible_assignment_types(expr, target, p, ctype, where, '=');
1920 }
1921
1922 i++;
1923 NEXT_PTR_LIST(argtype);
1924 } END_FOR_EACH_PTR(expr);
1925 FINISH_PTR_LIST(argtype);
1926 return 1;
1927 }
1928
1929 static void evaluate_initializer(struct symbol *ctype, struct expression **ep);
1930
1931 static int evaluate_one_array_initializer(struct symbol *ctype, struct expression **ep, int current)
1932 {
1933 struct expression *entry = *ep;
1934 struct expression **parent, *reuse = NULL;
1935 unsigned long offset;
1936 struct symbol *sym;
1937 unsigned long from, to;
1938 int accept_string = is_byte_type(ctype);
1939
1940 from = current;
1941 to = from+1;
1942 parent = ep;
1943 if (entry->type == EXPR_INDEX) {
1944 from = entry->idx_from;
1945 to = entry->idx_to+1;
1946 parent = &entry->idx_expression;
1947 reuse = entry;
1948 entry = entry->idx_expression;
1949 }
1950
1951 offset = from * (ctype->bit_size>>3);
1952 if (offset) {
1953 if (!reuse) reuse = alloc_expression(entry->pos, EXPR_POS);
1954 reuse->type = EXPR_POS;
1955 reuse->ctype = ctype;
1956 reuse->init_offset = offset;
1957 reuse->init_nr = to - from;
1958 reuse->init_expr = entry;
1959 parent = &reuse->init_expr;
1960 entry = reuse;
1961 }
1962 *ep = entry;
1963
1964 if (accept_string && entry->type == EXPR_STRING) {
1965 sym = evaluate_expression(entry);
1966 to = from + get_expression_value(sym->array_size);
1967 } else {
1968 evaluate_initializer(ctype, parent);
1969 }
1970 return to;
1971 }
1972
1973 static void evaluate_array_initializer(struct symbol *ctype, struct expression *expr)
1974 {
1975 struct expression *entry;
1976 int current = 0;
1977
1978 FOR_EACH_PTR(expr->expr_list, entry) {
1979 current = evaluate_one_array_initializer(ctype, THIS_ADDRESS(entry), current);
1980 } END_FOR_EACH_PTR(entry);
1981 }
1982
1983 /* A scalar initializer is allowed, and acts pretty much like an array of one */
1984 static void evaluate_scalar_initializer(struct symbol *ctype, struct expression *expr)
1985 {
1986 if (expression_list_size(expr->expr_list) != 1) {
1987 expression_error(expr, "unexpected compound initializer");
1988 return;
1989 }
1990 evaluate_array_initializer(ctype, expr);
1991 return;
1992 }
1993
1994 static struct symbol *find_struct_ident(struct symbol *ctype, struct ident *ident)
1995 {
1996 struct symbol *sym;
1997
1998 FOR_EACH_PTR(ctype->symbol_list, sym) {
1999 if (sym->ident == ident)
2000 return sym;
2001 } END_FOR_EACH_PTR(sym);
2002 return NULL;
2003 }
2004
2005 static int evaluate_one_struct_initializer(struct symbol *ctype, struct expression **ep, struct symbol *sym)
2006 {
2007 struct expression *entry = *ep;
2008 struct expression **parent;
2009 struct expression *reuse = NULL;
2010 unsigned long offset;
2011
2012 if (!sym) {
2013 expression_error(entry, "unknown named initializer");
2014 return -1;
2015 }
2016
2017 if (entry->type == EXPR_IDENTIFIER) {
2018 reuse = entry;
2019 entry = entry->ident_expression;
2020 }
2021
2022 parent = ep;
2023 offset = sym->offset;
2024 if (offset) {
2025 if (!reuse)
2026 reuse = alloc_expression(entry->pos, EXPR_POS);
2027 reuse->type = EXPR_POS;
2028 reuse->ctype = sym;
2029 reuse->init_offset = offset;
2030 reuse->init_nr = 1;
2031 reuse->init_expr = entry;
2032 parent = &reuse->init_expr;
2033 entry = reuse;
2034 }
2035 *ep = entry;
2036 evaluate_initializer(sym, parent);
2037 return 0;
2038 }
2039
2040 static void evaluate_struct_or_union_initializer(struct symbol *ctype, struct expression *expr, int multiple)
2041 {
2042 struct expression *entry;
2043 struct symbol *sym;
2044
2045 PREPARE_PTR_LIST(ctype->symbol_list, sym);
2046 FOR_EACH_PTR(expr->expr_list, entry) {
2047 if (entry->type == EXPR_IDENTIFIER) {
2048 struct ident *ident = entry->expr_ident;
2049 /* We special-case the "already right place" case */
2050 if (!sym || sym->ident != ident) {
2051 RESET_PTR_LIST(sym);
2052 for (;;) {
2053 if (!sym)
2054 break;
2055 if (sym->ident == ident)
2056 break;
2057 NEXT_PTR_LIST(sym);
2058 }
2059 }
2060 }
2061 if (evaluate_one_struct_initializer(ctype, THIS_ADDRESS(entry), sym))
2062 return;
2063 NEXT_PTR_LIST(sym);
2064 } END_FOR_EACH_PTR(entry);
2065 FINISH_PTR_LIST(sym);
2066 }
2067
2068 /*
2069 * Initializers are kind of like assignments. Except
2070 * they can be a hell of a lot more complex.
2071 */
2072 static void evaluate_initializer(struct symbol *ctype, struct expression **ep)
2073 {
2074 struct expression *expr = *ep;
2075
2076 /*
2077 * Simple non-structure/array initializers are the simple
2078 * case, and look (and parse) largely like assignments.
2079 */
2080 switch (expr->type) {
2081 default: {
2082 int is_string = expr->type == EXPR_STRING;
2083 struct symbol *rtype = evaluate_expression(expr);
2084 if (rtype) {
2085 /*
2086 * Special case:
2087 * char array[] = "string"
2088 * should _not_ degenerate.
2089 */
2090 if (!is_string || !is_string_type(ctype))
2091 rtype = degenerate(expr);
2092 compatible_assignment_types(expr, ctype, ep, rtype, "initializer", '=');
2093 }
2094 return;
2095 }
2096
2097 case EXPR_INITIALIZER:
2098 expr->ctype = ctype;
2099 if (ctype->type == SYM_NODE)
2100 ctype = ctype->ctype.base_type;
2101
2102 switch (ctype->type) {
2103 case SYM_ARRAY:
2104 case SYM_PTR:
2105 evaluate_array_initializer(get_base_type(ctype), expr);
2106 return;
2107 case SYM_UNION:
2108 evaluate_struct_or_union_initializer(ctype, expr, 0);
2109 return;
2110 case SYM_STRUCT:
2111 evaluate_struct_or_union_initializer(ctype, expr, 1);
2112 return;
2113 default:
2114 evaluate_scalar_initializer(ctype, expr);
2115 return;
2116 }
2117
2118 case EXPR_IDENTIFIER:
2119 if (ctype->type == SYM_NODE)
2120 ctype = ctype->ctype.base_type;
2121 if (ctype->type != SYM_STRUCT && ctype->type != SYM_UNION) {
2122 expression_error(expr, "expected structure or union for '%s' dereference", show_ident(expr->expr_ident));
2123 show_symbol(ctype);
2124 return;
2125 }
2126 evaluate_one_struct_initializer(ctype, ep,
2127 find_struct_ident(ctype, expr->expr_ident));
2128 return;
2129
2130 case EXPR_INDEX:
2131 if (ctype->type == SYM_NODE)
2132 ctype = ctype->ctype.base_type;
2133 if (ctype->type != SYM_ARRAY) {
2134 expression_error(expr, "expected array");
2135 return;
2136 }
2137 evaluate_one_array_initializer(ctype->ctype.base_type, ep, 0);
2138 return;
2139
2140 case EXPR_POS:
2141 /*
2142 * An EXPR_POS expression has already been evaluated, and we don't
2143 * need to do anything more
2144 */
2145 return;
2146 }
2147 }
2148
2149 static int get_as(struct symbol *sym)
2150 {
2151 int as;
2152 unsigned long mod;
2153
2154 if (!sym)
2155 return 0;
2156 as = sym->ctype.as;
2157 mod = sym->ctype.modifiers;
2158 if (sym->type == SYM_NODE) {
2159 sym = sym->ctype.base_type;
2160 as |= sym->ctype.as;
2161 mod |= sym->ctype.modifiers;
2162 }
2163
2164 /*
2165 * At least for now, allow casting to a "unsigned long".
2166 * That's how we do things like pointer arithmetic and
2167 * store pointers to registers.
2168 */
2169 if (sym == &ulong_ctype)
2170 return -1;
2171
2172 if (sym && sym->type == SYM_PTR) {
2173 sym = get_base_type(sym);
2174 as |= sym->ctype.as;
2175 mod |= sym->ctype.modifiers;
2176 }
2177 if (mod & MOD_FORCE)
2178 return -1;
2179 return as;
2180 }
2181
2182 static void cast_to_as(struct expression *e, int as)
2183 {
2184 struct expression *v = e->cast_expression;
2185 struct symbol *type = v->ctype;
2186
2187 if (!Wcast_to_address_space)
2188 return;
2189
2190 if (v->type != EXPR_VALUE || v->value)
2191 goto out;
2192
2193 /* cast from constant 0 to pointer is OK */
2194 if (is_int_type(type))
2195 return;
2196
2197 if (type->type == SYM_NODE)
2198 type = type->ctype.base_type;
2199
2200 if (type->type == SYM_PTR && type->ctype.base_type == &void_ctype)
2201 return;
2202
2203 out:
2204 warning(e->pos, "cast adds address space to expression (<asn:%d>)", as);
2205 }
2206
2207 static struct symbol *evaluate_cast(struct expression *expr)
2208 {
2209 struct expression *target = expr->cast_expression;
2210 struct symbol *ctype = examine_symbol_type(expr->cast_type);
2211 struct symbol *t1, *t2;
2212 int class1, class2;
2213 int as1, as2;
2214
2215 if (!target)
2216 return NULL;
2217
2218 expr->ctype = ctype;
2219 expr->cast_type = ctype;
2220
2221 /*
2222 * Special case: a cast can be followed by an
2223 * initializer, in which case we need to pass
2224 * the type value down to that initializer rather
2225 * than trying to evaluate it as an expression
2226 *
2227 * A more complex case is when the initializer is
2228 * dereferenced as part of a post-fix expression.
2229 * We need to produce an expression that can be dereferenced.
2230 */
2231 if (target->type == EXPR_INITIALIZER) {
2232 struct symbol *sym = expr->cast_type;
2233 struct expression *addr = alloc_expression(expr->pos, EXPR_SYMBOL);
2234
2235 sym->initializer = expr->cast_expression;
2236 evaluate_symbol(sym);
2237
2238 addr->ctype = &lazy_ptr_ctype; /* Lazy eval */
2239 addr->symbol = sym;
2240
2241 expr->type = EXPR_PREOP;
2242 expr->op = '*';
2243 expr->unop = addr;
2244 expr->ctype = sym;
2245
2246 return sym;
2247 }
2248
2249 evaluate_expression(target);
2250 degenerate(target);
2251
2252 class1 = classify_type(ctype, &t1);
2253 /*
2254 * You can always throw a value away by casting to
2255 * "void" - that's an implicit "force". Note that
2256 * the same is _not_ true of "void *".
2257 */
2258 if (t1 == &void_ctype)
2259 goto out;
2260
2261 if (class1 & TYPE_COMPOUND)
2262 warning(expr->pos, "cast to non-scalar");
2263
2264 t2 = target->ctype;
2265 if (!t2) {
2266 expression_error(expr, "cast from unknown type");
2267 goto out;
2268 }
2269 class2 = classify_type(t2, &t2);
2270
2271 if (class2 & TYPE_COMPOUND)
2272 warning(expr->pos, "cast from non-scalar");
2273
2274 /* allowed cast unfouls */
2275 if (class2 & TYPE_FOULED)
2276 t2 = t2->ctype.base_type;
2277
2278 if (!(ctype->ctype.modifiers & MOD_FORCE) && t1 != t2) {
2279 if (class1 & TYPE_RESTRICT)
2280 warning(expr->pos, "cast to restricted type");
2281 if (class2 & TYPE_RESTRICT)
2282 warning(expr->pos, "cast from restricted type");
2283 }
2284
2285 as1 = get_as(ctype);
2286 as2 = get_as(target->ctype);
2287 if (!as1 && as2 > 0)
2288 warning(expr->pos, "cast removes address space of expression");
2289 if (as1 > 0 && as2 > 0 && as1 != as2)
2290 warning(expr->pos, "cast between address spaces (<asn:%d>-><asn:%d>)", as2, as1);
2291 if (as1 > 0 && !as2)
2292 cast_to_as(expr, as1);
2293
2294 /*
2295 * Casts of constant values are special: they
2296 * can be NULL, and thus need to be simplified
2297 * early.
2298 */
2299 if (target->type == EXPR_VALUE)
2300 cast_value(expr, ctype, target, target->ctype);
2301
2302 out:
2303 return ctype;
2304 }
2305
2306 /*
2307 * Evaluate a call expression with a symbol. This
2308 * should expand inline functions, and evaluate
2309 * builtins.
2310 */
2311 static int evaluate_symbol_call(struct expression *expr)
2312 {
2313 struct expression *fn = expr->fn;
2314 struct symbol *ctype = fn->ctype;
2315
2316 if (fn->type != EXPR_PREOP)
2317 return 0;
2318
2319 if (ctype->op && ctype->op->evaluate)
2320 return ctype->op->evaluate(expr);
2321
2322 if (ctype->ctype.modifiers & MOD_INLINE) {
2323 int ret;
2324 struct symbol *curr = current_fn;
2325 current_fn = ctype->ctype.base_type;
2326
2327 ret = inline_function(expr, ctype);
2328
2329 /* restore the old function */
2330 current_fn = curr;
2331 return ret;
2332 }
2333
2334 return 0;
2335 }
2336
2337 static struct symbol *evaluate_call(struct expression *expr)
2338 {
2339 int args, fnargs;
2340 struct symbol *ctype, *sym;
2341 struct expression *fn = expr->fn;
2342 struct expression_list *arglist = expr->args;
2343
2344 if (!evaluate_expression(fn))
2345 return NULL;
2346 sym = ctype = fn->ctype;
2347 if (ctype->type == SYM_NODE)
2348 ctype = ctype->ctype.base_type;
2349 if (ctype->type == SYM_PTR || ctype->type == SYM_ARRAY)
2350 ctype = get_base_type(ctype);
2351
2352 examine_fn_arguments(ctype);
2353 if (sym->type == SYM_NODE && fn->type == EXPR_PREOP &&
2354 sym->op && sym->op->args) {
2355 if (!sym->op->args(expr))
2356 return NULL;
2357 } else {
2358 if (!evaluate_arguments(sym, ctype, arglist))
2359 return NULL;
2360 if (ctype->type != SYM_FN) {
2361 expression_error(expr, "not a function %s",
2362 show_ident(sym->ident));
2363 return NULL;
2364 }
2365 args = expression_list_size(expr->args);
2366 fnargs = symbol_list_size(ctype->arguments);
2367 if (args < fnargs)
2368 expression_error(expr,
2369 "not enough arguments for function %s",
2370 show_ident(sym->ident));
2371 if (args > fnargs && !ctype->variadic)
2372 expression_error(expr,
2373 "too many arguments for function %s",
2374 show_ident(sym->ident));
2375 }
2376 if (sym->type == SYM_NODE) {
2377 if (evaluate_symbol_call(expr))
2378 return expr->ctype;
2379 }
2380 expr->ctype = ctype->ctype.base_type;
2381 return expr->ctype;
2382 }
2383
2384 struct symbol *evaluate_expression(struct expression *expr)
2385 {
2386 if (!expr)
2387 return NULL;
2388 if (expr->ctype)
2389 return expr->ctype;
2390
2391 switch (expr->type) {
2392 case EXPR_VALUE:
2393 case EXPR_FVALUE:
2394 expression_error(expr, "value expression without a type");
2395 return NULL;
2396 case EXPR_STRING:
2397 return evaluate_string(expr);
2398 case EXPR_SYMBOL:
2399 return evaluate_symbol_expression(expr);
2400 case EXPR_BINOP:
2401 if (!evaluate_expression(expr->left))
2402 return NULL;
2403 if (!evaluate_expression(expr->right))
2404 return NULL;
2405 return evaluate_binop(expr);
2406 case EXPR_LOGICAL:
2407 return evaluate_logical(expr);
2408 case EXPR_COMMA:
2409 evaluate_expression(expr->left);
2410 if (!evaluate_expression(expr->right))
2411 return NULL;
2412 return evaluate_comma(expr);
2413 case EXPR_COMPARE:
2414 if (!evaluate_expression(expr->left))
2415 return NULL;
2416 if (!evaluate_expression(expr->right))
2417 return NULL;
2418 return evaluate_compare(expr);
2419 case EXPR_ASSIGNMENT:
2420 if (!evaluate_expression(expr->left))
2421 return NULL;
2422 if (!evaluate_expression(expr->right))
2423 return NULL;
2424 return evaluate_assignment(expr);
2425 case EXPR_PREOP:
2426 if (!evaluate_expression(expr->unop))
2427 return NULL;
2428 return evaluate_preop(expr);
2429 case EXPR_POSTOP:
2430 if (!evaluate_expression(expr->unop))
2431 return NULL;
2432 return evaluate_postop(expr);
2433 case EXPR_CAST:
2434 case EXPR_IMPLIED_CAST:
2435 return evaluate_cast(expr);
2436 case EXPR_SIZEOF:
2437 return evaluate_sizeof(expr);
2438 case EXPR_PTRSIZEOF:
2439 return evaluate_ptrsizeof(expr);
2440 case EXPR_ALIGNOF:
2441 return evaluate_alignof(expr);
2442 case EXPR_DEREF:
2443 return evaluate_member_dereference(expr);
2444 case EXPR_CALL:
2445 return evaluate_call(expr);
2446 case EXPR_SELECT:
2447 case EXPR_CONDITIONAL:
2448 return evaluate_conditional_expression(expr);
2449 case EXPR_STATEMENT:
2450 expr->ctype = evaluate_statement(expr->statement);
2451 return expr->ctype;
2452
2453 case EXPR_LABEL:
2454 expr->ctype = &ptr_ctype;
2455 return &ptr_ctype;
2456
2457 case EXPR_TYPE:
2458 /* Evaluate the type of the symbol .. */
2459 evaluate_symbol(expr->symbol);
2460 /* .. but the type of the _expression_ is a "type" */
2461 expr->ctype = &type_ctype;
2462 return &type_ctype;
2463
2464 /* These can not exist as stand-alone expressions */
2465 case EXPR_INITIALIZER:
2466 case EXPR_IDENTIFIER:
2467 case EXPR_INDEX:
2468 case EXPR_POS:
2469 expression_error(expr, "internal front-end error: initializer in expression");
2470 return NULL;
2471 case EXPR_SLICE:
2472 expression_error(expr, "internal front-end error: SLICE re-evaluated");
2473 return NULL;
2474 }
2475 return NULL;
2476 }
2477
2478 static void check_duplicates(struct symbol *sym)
2479 {
2480 int declared = 0;
2481 struct symbol *next = sym;
2482
2483 while ((next = next->same_symbol) != NULL) {
2484 const char *typediff;
2485 evaluate_symbol(next);
2486 declared++;
2487 typediff = type_difference(sym, next, 0, 0);
2488 if (typediff) {
2489 sparse_error(sym->pos, "symbol '%s' redeclared with different type (originally declared at %s:%d) - %s",
2490 show_ident(sym->ident),
2491 stream_name(next->pos.stream), next->pos.line, typediff);
2492 return;
2493 }
2494 }
2495 if (!declared) {
2496 unsigned long mod = sym->ctype.modifiers;
2497 if (mod & (MOD_STATIC | MOD_REGISTER))
2498 return;
2499 if (!(mod & MOD_TOPLEVEL))
2500 return;
2501 if (!Wdecl)
2502 return;
2503 if (sym->ident == &main_ident)
2504 return;
2505 warning(sym->pos, "symbol '%s' was not declared. Should it be static?", show_ident(sym->ident));
2506 }
2507 }
2508
2509 static struct symbol *evaluate_symbol(struct symbol *sym)
2510 {
2511 struct symbol *base_type;
2512
2513 if (!sym)
2514 return sym;
2515 if (sym->evaluated)
2516 return sym;
2517 sym->evaluated = 1;
2518
2519 sym = examine_symbol_type(sym);
2520 base_type = get_base_type(sym);
2521 if (!base_type)
2522 return NULL;
2523
2524 /* Evaluate the initializers */
2525 if (sym->initializer)
2526 evaluate_initializer(sym, &sym->initializer);
2527
2528 /* And finally, evaluate the body of the symbol too */
2529 if (base_type->type == SYM_FN) {
2530 struct symbol *curr = current_fn;
2531
2532 current_fn = base_type;
2533
2534 examine_fn_arguments(base_type);
2535 if (!base_type->stmt && base_type->inline_stmt)
2536 uninline(sym);
2537 if (base_type->stmt)
2538 evaluate_statement(base_type->stmt);
2539
2540 current_fn = curr;
2541 }
2542
2543 return base_type;
2544 }
2545
2546 void evaluate_symbol_list(struct symbol_list *list)
2547 {
2548 struct symbol *sym;
2549
2550 FOR_EACH_PTR(list, sym) {
2551 evaluate_symbol(sym);
2552 check_duplicates(sym);
2553 } END_FOR_EACH_PTR(sym);
2554 }
2555
2556 static struct symbol *evaluate_return_expression(struct statement *stmt)
2557 {
2558 struct expression *expr = stmt->expression;
2559 struct symbol *ctype, *fntype;
2560
2561 evaluate_expression(expr);
2562 ctype = degenerate(expr);
2563 fntype = current_fn->ctype.base_type;
2564 if (!fntype || fntype == &void_ctype) {
2565 if (expr && ctype != &void_ctype)
2566 expression_error(expr, "return expression in %s function", fntype?"void":"typeless");
2567 return NULL;
2568 }
2569
2570 if (!expr) {
2571 sparse_error(stmt->pos, "return with no return value");
2572 return NULL;
2573 }
2574 if (!ctype)
2575 return NULL;
2576 compatible_assignment_types(expr, fntype, &stmt->expression, ctype, "return expression", '=');
2577 return NULL;
2578 }
2579
2580 static void evaluate_if_statement(struct statement *stmt)
2581 {
2582 if (!stmt->if_conditional)
2583 return;
2584
2585 evaluate_conditional(stmt->if_conditional, 0);
2586 evaluate_statement(stmt->if_true);
2587 evaluate_statement(stmt->if_false);
2588 }
2589
2590 static void evaluate_iterator(struct statement *stmt)
2591 {
2592 evaluate_conditional(stmt->iterator_pre_condition, 1);
2593 evaluate_conditional(stmt->iterator_post_condition,1);
2594 evaluate_statement(stmt->iterator_pre_statement);
2595 evaluate_statement(stmt->iterator_statement);
2596 evaluate_statement(stmt->iterator_post_statement);
2597 }
2598
2599 static void verify_output_constraint(struct expression *expr, const char *constraint)
2600 {
2601 switch (*constraint) {
2602 case '=': /* Assignment */
2603 case '+': /* Update */
2604 break;
2605 default:
2606 expression_error(expr, "output constraint is not an assignment constraint (\"%s\")", constraint);
2607 }
2608 }
2609
2610 static void verify_input_constraint(struct expression *expr, const char *constraint)
2611 {
2612 switch (*constraint) {
2613 case '=': /* Assignment */
2614 case '+': /* Update */
2615 expression_error(expr, "input constraint with assignment (\"%s\")", constraint);
2616 }
2617 }
2618
2619 static void evaluate_asm_statement(struct statement *stmt)
2620 {
2621 struct expression *expr;
2622 int state;
2623
2624 expr = stmt->asm_string;
2625 if (!expr || expr->type != EXPR_STRING) {
2626 sparse_error(stmt->pos, "need constant string for inline asm");
2627 return;
2628 }
2629
2630 state = 0;
2631 FOR_EACH_PTR(stmt->asm_outputs, expr) {
2632 struct ident *ident;
2633
2634 switch (state) {
2635 case 0: /* Identifier */
2636 state = 1;
2637 ident = (struct ident *)expr;
2638 continue;
2639
2640 case 1: /* Constraint */
2641 state = 2;
2642 if (!expr || expr->type != EXPR_STRING) {
2643 sparse_error(expr ? expr->pos : stmt->pos, "asm output constraint is not a string");
2644 *THIS_ADDRESS(expr) = NULL;
2645 continue;
2646 }
2647 verify_output_constraint(expr, expr->string->data);
2648 continue;
2649
2650 case 2: /* Expression */
2651 state = 0;
2652 if (!evaluate_expression(expr))
2653 return;
2654 if (!lvalue_expression(expr))
2655 warning(expr->pos, "asm output is not an lvalue");
2656 evaluate_assign_to(expr, expr->ctype);
2657 continue;
2658 }
2659 } END_FOR_EACH_PTR(expr);
2660
2661 state = 0;
2662 FOR_EACH_PTR(stmt->asm_inputs, expr) {
2663 struct ident *ident;
2664
2665 switch (state) {
2666 case 0: /* Identifier */
2667 state = 1;
2668 ident = (struct ident *)expr;
2669 continue;
2670
2671 case 1: /* Constraint */
2672 state = 2;
2673 if (!expr || expr->type != EXPR_STRING) {
2674 sparse_error(expr ? expr->pos : stmt->pos, "asm input constraint is not a string");
2675 *THIS_ADDRESS(expr) = NULL;
2676 continue;
2677 }
2678 verify_input_constraint(expr, expr->string->data);
2679 continue;
2680
2681 case 2: /* Expression */
2682 state = 0;
2683 if (!evaluate_expression(expr))
2684 return;
2685 continue;
2686 }
2687 } END_FOR_EACH_PTR(expr);
2688
2689 FOR_EACH_PTR(stmt->asm_clobbers, expr) {
2690 if (!expr) {
2691 sparse_error(stmt->pos, "bad asm output");
2692 return;
2693 }
2694 if (expr->type == EXPR_STRING)
2695 continue;
2696 expression_error(expr, "asm clobber is not a string");
2697 } END_FOR_EACH_PTR(expr);
2698 }
2699
2700 static void evaluate_case_statement(struct statement *stmt)
2701 {
2702 evaluate_expression(stmt->case_expression);
2703 evaluate_expression(stmt->case_to);
2704 evaluate_statement(stmt->case_statement);
2705 }
2706
2707 static void check_case_type(struct expression *switch_expr,
2708 struct expression *case_expr,
2709 struct expression **enumcase)
2710 {
2711 struct symbol *switch_type, *case_type;
2712 int sclass, cclass;
2713
2714 if (!case_expr)
2715 return;
2716
2717 switch_type = switch_expr->ctype;
2718 case_type = evaluate_expression(case_expr);
2719
2720 if (!switch_type || !case_type)
2721 goto Bad;
2722 if (enumcase) {
2723 if (*enumcase)
2724 warn_for_different_enum_types(case_expr->pos, case_type, (*enumcase)->ctype);
2725 else if (is_enum_type(case_type))
2726 *enumcase = case_expr;
2727 }
2728
2729 sclass = classify_type(switch_type, &switch_type);
2730 cclass = classify_type(case_type, &case_type);
2731
2732 /* both should be arithmetic */
2733 if (!(sclass & cclass & TYPE_NUM))
2734 goto Bad;
2735
2736 /* neither should be floating */
2737 if ((sclass | cclass) & TYPE_FLOAT)
2738 goto Bad;
2739
2740 /* if neither is restricted, we are OK */
2741 if (!((sclass | cclass) & TYPE_RESTRICT))
2742 return;
2743
2744 if (!restricted_binop_type(SPECIAL_EQUAL, case_expr, switch_expr,
2745 cclass, sclass, case_type, switch_type))
2746 warning(case_expr->pos, "restricted degrades to integer");
2747
2748 return;
2749
2750 Bad:
2751 expression_error(case_expr, "incompatible types for 'case' statement");
2752 }
2753
2754 static void evaluate_switch_statement(struct statement *stmt)
2755 {
2756 struct symbol *sym;
2757 struct expression *enumcase = NULL;
2758 struct expression **enumcase_holder = &enumcase;
2759 struct expression *sel = stmt->switch_expression;
2760
2761 evaluate_expression(sel);
2762 evaluate_statement(stmt->switch_statement);
2763 if (!sel)
2764 return;
2765 if (sel->ctype && is_enum_type(sel->ctype))
2766 enumcase_holder = NULL; /* Only check cases against switch */
2767
2768 FOR_EACH_PTR(stmt->switch_case->symbol_list, sym) {
2769 struct statement *case_stmt = sym->stmt;
2770 check_case_type(sel, case_stmt->case_expression, enumcase_holder);
2771 check_case_type(sel, case_stmt->case_to, enumcase_holder);
2772 } END_FOR_EACH_PTR(sym);
2773 }
2774
2775 struct symbol *evaluate_statement(struct statement *stmt)
2776 {
2777 if (!stmt)
2778 return NULL;
2779
2780 switch (stmt->type) {
2781 case STMT_DECLARATION: {
2782 struct symbol *s;
2783 FOR_EACH_PTR(stmt->declaration, s) {
2784 evaluate_symbol(s);
2785 } END_FOR_EACH_PTR(s);
2786 return NULL;
2787 }
2788
2789 case STMT_RETURN:
2790 return evaluate_return_expression(stmt);
2791
2792 case STMT_EXPRESSION:
2793 if (!evaluate_expression(stmt->expression))
2794 return NULL;
2795 return degenerate(stmt->expression);
2796
2797 case STMT_COMPOUND: {
2798 struct statement *s;
2799 struct symbol *type = NULL;
2800
2801 /* Evaluate the return symbol in the compound statement */
2802 evaluate_symbol(stmt->ret);
2803
2804 /*
2805 * Then, evaluate each statement, making the type of the
2806 * compound statement be the type of the last statement
2807 */
2808 type = evaluate_statement(stmt->args);
2809 FOR_EACH_PTR(stmt->stmts, s) {
2810 type = evaluate_statement(s);
2811 } END_FOR_EACH_PTR(s);
2812 if (!type)
2813 type = &void_ctype;
2814 return type;
2815 }
2816 case STMT_IF:
2817 evaluate_if_statement(stmt);
2818 return NULL;
2819 case STMT_ITERATOR:
2820 evaluate_iterator(stmt);
2821 return NULL;
2822 case STMT_SWITCH:
2823 evaluate_switch_statement(stmt);
2824 return NULL;
2825 case STMT_CASE:
2826 evaluate_case_statement(stmt);
2827 return NULL;
2828 case STMT_LABEL:
2829 return evaluate_statement(stmt->label_statement);
2830 case STMT_GOTO:
2831 evaluate_expression(stmt->goto_expression);
2832 return NULL;
2833 case STMT_NONE:
2834 break;
2835 case STMT_ASM:
2836 evaluate_asm_statement(stmt);
2837 return NULL;
2838 case STMT_CONTEXT:
2839 evaluate_expression(stmt->expression);
2840 return NULL;
2841 case STMT_RANGE:
2842 evaluate_expression(stmt->range_expression);
2843 evaluate_expression(stmt->range_low);
2844 evaluate_expression(stmt->range_high);
2845 return NULL;
2846 }
2847 return NULL;
2848 }
Static analysis for C