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db: do the caller_info stuff earlier
[smatch.git] / evaluate.c
blob6c930e8de8a1b9aa6e608795049d40f3ba277350
1 /*
2 * sparse/evaluate.c
3 *
4 * Copyright (C) 2003 Transmeta Corp.
5 * 2003-2004 Linus Torvalds
6 *
7 * Permission is hereby granted, free of charge, to any person obtaining a copy
8 * of this software and associated documentation files (the "Software"), to deal
9 * in the Software without restriction, including without limitation the rights
10 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
11 * copies of the Software, and to permit persons to whom the Software is
12 * furnished to do so, subject to the following conditions:
13 *
14 * The above copyright notice and this permission notice shall be included in
15 * all copies or substantial portions of the Software.
16 *
17 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
18 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
19 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
20 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
21 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
22 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
23 * THE SOFTWARE.
24 *
25 * Evaluate constant expressions.
26 */
27 #include <stdlib.h>
28 #include <stdarg.h>
29 #include <stddef.h>
30 #include <stdio.h>
31 #include <string.h>
32 #include <ctype.h>
33 #include <unistd.h>
34 #include <fcntl.h>
35 #include <limits.h>
36
37 #include "evaluate.h"
38 #include "lib.h"
39 #include "allocate.h"
40 #include "parse.h"
41 #include "token.h"
42 #include "symbol.h"
43 #include "target.h"
44 #include "expression.h"
45
46 struct symbol *current_fn;
47
48 struct ident bad_address_space = { .len = 6, .name = "bad AS", };
49
50 static struct symbol *degenerate(struct expression *expr);
51 static struct symbol *evaluate_symbol(struct symbol *sym);
52
53 static inline int valid_expr_type(struct expression *expr)
54 {
55 return expr && valid_type(expr->ctype);
56 }
57
58 static inline int valid_subexpr_type(struct expression *expr)
59 {
60 return valid_expr_type(expr->left)
61 && valid_expr_type(expr->right);
62 }
63
64 static struct symbol *unqualify_type(struct symbol *ctype)
65 {
66 if (!ctype)
67 return ctype;
68 if (ctype->type == SYM_NODE && (ctype->ctype.modifiers & MOD_QUALIFIER)) {
69 struct symbol *unqual = alloc_symbol(ctype->pos, 0);
70
71 *unqual = *ctype;
72 unqual->ctype.modifiers &= ~MOD_QUALIFIER;
73 return unqual;
74 }
75 return ctype;
76 }
77
78 static struct symbol *evaluate_symbol_expression(struct expression *expr)
79 {
80 struct expression *addr;
81 struct symbol *sym = expr->symbol;
82 struct symbol *base_type;
83
84 if (!sym) {
85 expression_error(expr, "undefined identifier '%s'", show_ident(expr->symbol_name));
86 return NULL;
87 }
88
89 examine_symbol_type(sym);
90
91 base_type = get_base_type(sym);
92 if (!base_type) {
93 expression_error(expr, "identifier '%s' has no type", show_ident(expr->symbol_name));
94 return NULL;
95 }
96
97 addr = alloc_expression(expr->pos, EXPR_SYMBOL);
98 addr->symbol = sym;
99 addr->symbol_name = expr->symbol_name;
100 addr->ctype = &lazy_ptr_ctype; /* Lazy evaluation: we need to do a proper job if somebody does &sym */
101 addr->flags = expr->flags;
102 expr->type = EXPR_PREOP;
103 expr->op = '*';
104 expr->unop = addr;
105 expr->flags = CEF_NONE;
106
107 /* The type of a symbol is the symbol itself! */
108 expr->ctype = sym;
109 return sym;
110 }
111
112 static struct symbol *evaluate_string(struct expression *expr)
113 {
114 struct symbol *sym = alloc_symbol(expr->pos, SYM_NODE);
115 struct symbol *array = alloc_symbol(expr->pos, SYM_ARRAY);
116 struct expression *addr = alloc_expression(expr->pos, EXPR_SYMBOL);
117 struct expression *initstr = alloc_expression(expr->pos, EXPR_STRING);
118 unsigned int length = expr->string->length;
119 struct symbol *char_type = expr->wide ? wchar_ctype : &char_ctype;
120
121 sym->array_size = alloc_const_expression(expr->pos, length);
122 sym->bit_size = length * char_type->bit_size;
123 sym->ctype.alignment = 1;
124 sym->string = 1;
125 sym->ctype.modifiers = MOD_STATIC;
126 sym->ctype.base_type = array;
127 sym->initializer = initstr;
128 sym->examined = 1;
129 sym->evaluated = 1;
130
131 initstr->ctype = sym;
132 initstr->string = expr->string;
133
134 array->array_size = sym->array_size;
135 array->bit_size = sym->bit_size;
136 array->ctype.alignment = char_type->ctype.alignment;
137 array->ctype.modifiers = MOD_STATIC;
138 array->ctype.base_type = char_type;
139 array->examined = 1;
140 array->evaluated = 1;
141
142 addr->symbol = sym;
143 addr->ctype = &lazy_ptr_ctype;
144 addr->flags = CEF_ADDR;
145
146 expr->type = EXPR_PREOP;
147 expr->op = '*';
148 expr->unop = addr;
149 expr->ctype = sym;
150 return sym;
151 }
152
153 /* type has come from classify_type and is an integer type */
154 static inline struct symbol *integer_promotion(struct symbol *type)
155 {
156 unsigned long mod = type->ctype.modifiers;
157 int width = type->bit_size;
158
159 /*
160 * Bitfields always promote to the base type,
161 * even if the bitfield might be bigger than
162 * an "int".
163 */
164 if (type->type == SYM_BITFIELD) {
165 type = type->ctype.base_type;
166 }
167 mod = type->ctype.modifiers;
168 if (width < bits_in_int)
169 return &int_ctype;
170
171 /* If char/short has as many bits as int, it still gets "promoted" */
172 if (type->rank < 0) {
173 if (mod & MOD_UNSIGNED)
174 return &uint_ctype;
175 return &int_ctype;
176 }
177 return type;
178 }
179
180 /*
181 * After integer promotons:
182 * If both types are the same
183 * -> no conversion needed
184 * If the types have the same signedness (their rank must be different)
185 * -> convert to the type of the highest rank
186 * If rank(unsigned type) >= rank(signed type)
187 * -> convert to the unsigned type
188 * If size(signed type) > size(unsigned type)
189 * -> convert to the signed type
190 * Otherwise
191 * -> convert to the unsigned type corresponding to the signed type.
192 */
193 static struct symbol *bigger_int_type(struct symbol *left, struct symbol *right)
194 {
195 static struct symbol *unsigned_types[] = {
196 [0] = &uint_ctype,
197 [1] = &ulong_ctype,
198 [2] = &ullong_ctype,
199 [3] = &uint128_ctype,
200 };
201 unsigned long lmod, rmod;
202 struct symbol *stype, *utype;
203
204 left = integer_promotion(left);
205 right = integer_promotion(right);
206
207 if (left == right)
208 return left;
209
210 lmod = left->ctype.modifiers;
211 rmod = right->ctype.modifiers;
212 if (((lmod ^ rmod) & MOD_UNSIGNED) == 0)
213 return (left->rank > right->rank) ? left : right;
214 if (lmod & MOD_UNSIGNED) {
215 utype = left;
216 stype = right;
217 } else {
218 stype = left;
219 utype = right;
220 }
221 if (utype->rank >= stype->rank)
222 return utype;
223 if (stype->bit_size > utype->bit_size)
224 return stype;
225 utype = unsigned_types[stype->rank];
226 return utype;
227 }
228
229 static struct symbol *base_type(struct symbol *node, unsigned long *modp, struct ident **asp)
230 {
231 unsigned long mod = 0;
232 struct ident *as = NULL;
233
234 while (node) {
235 mod |= node->ctype.modifiers;
236 combine_address_space(node->pos, &as, node->ctype.as);
237 if (node->type == SYM_NODE) {
238 node = node->ctype.base_type;
239 continue;
240 }
241 break;
242 }
243 *modp = mod & ~MOD_IGNORE;
244 *asp = as;
245 return node;
246 }
247
248 static int is_same_type(struct expression *expr, struct symbol *new)
249 {
250 struct symbol *old = expr->ctype;
251 unsigned long oldmod, newmod;
252 struct ident *oldas, *newas;
253
254 old = base_type(old, &oldmod, &oldas);
255 new = base_type(new, &newmod, &newas);
256
257 /* Same base type, same address space? */
258 if (old == new && oldas == newas) {
259 unsigned long difmod;
260
261 /* Check the modifier bits. */
262 difmod = (oldmod ^ newmod) & ~MOD_NOCAST;
263
264 /* Exact same type? */
265 if (!difmod)
266 return 1;
267
268 /*
269 * Not the same type, but differs only in "const".
270 * Don't warn about MOD_NOCAST.
271 */
272 if (difmod == MOD_CONST)
273 return 0;
274 }
275 if ((oldmod | newmod) & MOD_NOCAST) {
276 const char *tofrom = "to/from";
277 if (!(newmod & MOD_NOCAST))
278 tofrom = "from";
279 if (!(oldmod & MOD_NOCAST))
280 tofrom = "to";
281 warning(expr->pos, "implicit cast %s nocast type", tofrom);
282 }
283 return 0;
284 }
285
286 static void
287 warn_for_different_enum_types (struct position pos,
288 struct symbol *typea,
289 struct symbol *typeb)
290 {
291 if (!Wenum_mismatch)
292 return;
293 if (typea->type == SYM_NODE)
294 typea = typea->ctype.base_type;
295 if (typeb->type == SYM_NODE)
296 typeb = typeb->ctype.base_type;
297
298 if (typea == typeb)
299 return;
300
301 if (typea->type == SYM_ENUM && typeb->type == SYM_ENUM) {
302 warning(pos, "mixing different enum types:");
303 info(pos, " %s", show_typename(typea));
304 info(pos, " %s", show_typename(typeb));
305 }
306 }
307
308 static int cast_flags(struct expression *expr, struct expression *target);
309 static struct symbol *cast_to_bool(struct expression *expr);
310
311 /*
312 * This gets called for implicit casts in assignments and
313 * integer promotion.
314 */
315 static struct expression * cast_to(struct expression *old, struct symbol *type)
316 {
317 struct expression *expr;
318
319 warn_for_different_enum_types (old->pos, old->ctype, type);
320
321 if (old->ctype != &null_ctype && is_same_type(old, type))
322 return old;
323
324 expr = alloc_expression(old->pos, EXPR_IMPLIED_CAST);
325 expr->ctype = type;
326 expr->cast_type = type;
327 expr->cast_expression = old;
328 expr->flags = cast_flags(expr, old);
329
330 if (is_bool_type(type))
331 cast_to_bool(expr);
332
333 return expr;
334 }
335
336 enum {
337 TYPE_NUM = 1,
338 TYPE_BITFIELD = 2,
339 TYPE_RESTRICT = 4,
340 TYPE_FLOAT = 8,
341 TYPE_PTR = 16,
342 TYPE_COMPOUND = 32,
343 TYPE_FOULED = 64,
344 TYPE_FN = 128,
345 };
346
347 static inline int classify_type(struct symbol *type, struct symbol **base)
348 {
349 static int type_class[SYM_BAD + 1] = {
350 [SYM_PTR] = TYPE_PTR,
351 [SYM_FN] = TYPE_PTR | TYPE_FN,
352 [SYM_ARRAY] = TYPE_PTR | TYPE_COMPOUND,
353 [SYM_STRUCT] = TYPE_COMPOUND,
354 [SYM_UNION] = TYPE_COMPOUND,
355 [SYM_BITFIELD] = TYPE_NUM | TYPE_BITFIELD,
356 [SYM_RESTRICT] = TYPE_NUM | TYPE_RESTRICT,
357 [SYM_FOULED] = TYPE_NUM | TYPE_RESTRICT | TYPE_FOULED,
358 };
359 if (type->type == SYM_NODE)
360 type = type->ctype.base_type;
361 if (type->type == SYM_TYPEOF) {
362 type = examine_symbol_type(type);
363 if (type->type == SYM_NODE)
364 type = type->ctype.base_type;
365 }
366 if (type->type == SYM_ENUM)
367 type = type->ctype.base_type;
368 *base = type;
369 if (type->type == SYM_BASETYPE) {
370 if (type->ctype.base_type == &int_type)
371 return TYPE_NUM;
372 if (type->ctype.base_type == &fp_type)
373 return TYPE_NUM | TYPE_FLOAT;
374 }
375 return type_class[type->type];
376 }
377
378 #define is_int(class) ((class & (TYPE_NUM | TYPE_FLOAT)) == TYPE_NUM)
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 if (type->type != SYM_ARRAY)
385 return 0;
386 type = type->ctype.base_type;
387 return is_byte_type(type) || is_wchar_type(type);
388 }
389
390 static struct symbol *bad_expr_type(struct expression *expr)
391 {
392 switch (expr->type) {
393 case EXPR_BINOP:
394 case EXPR_COMPARE:
395 if (!valid_subexpr_type(expr))
396 break;
397 sparse_error(expr->pos, "incompatible types for operation (%s):", show_special(expr->op));
398 info(expr->pos, " %s", show_typename(expr->left->ctype));
399 info(expr->pos, " %s", show_typename(expr->right->ctype));
400 break;
401 case EXPR_PREOP:
402 case EXPR_POSTOP:
403 if (!valid_expr_type(expr->unop))
404 break;
405 sparse_error(expr->pos, "incompatible type for operation (%s):", show_special(expr->op));
406 info(expr->pos, " %s", show_typename(expr->unop->ctype));
407 break;
408 default:
409 break;
410 }
411
412 expr->flags = CEF_NONE;
413 return expr->ctype = &bad_ctype;
414 }
415
416 static int restricted_value(struct expression *v, struct symbol *type)
417 {
418 if (v->type != EXPR_VALUE)
419 return 1;
420 if (v->value != 0)
421 return 1;
422 return 0;
423 }
424
425 static int restricted_binop(int op, struct symbol *type)
426 {
427 switch (op) {
428 case '&':
429 case '=':
430 case SPECIAL_AND_ASSIGN:
431 case SPECIAL_OR_ASSIGN:
432 case SPECIAL_XOR_ASSIGN:
433 return 1; /* unfoul */
434 case '|':
435 case '^':
436 case '?':
437 return 2; /* keep fouled */
438 case SPECIAL_EQUAL:
439 case SPECIAL_NOTEQUAL:
440 return 3; /* warn if fouled */
441 default:
442 return 0; /* warn */
443 }
444 }
445
446 static int restricted_unop(int op, struct symbol **type)
447 {
448 if (op == '~') {
449 if ((*type)->bit_size < bits_in_int)
450 *type = befoul(*type);
451 return 0;
452 } if (op == '+')
453 return 0;
454 return 1;
455 }
456
457 /* type should be SYM_FOULED */
458 static inline struct symbol *unfoul(struct symbol *type)
459 {
460 return type->ctype.base_type;
461 }
462
463 static struct symbol *restricted_binop_type(int op,
464 struct expression *left,
465 struct expression *right,
466 int lclass, int rclass,
467 struct symbol *ltype,
468 struct symbol *rtype)
469 {
470 struct symbol *ctype = NULL;
471 if (lclass & TYPE_RESTRICT) {
472 if (rclass & TYPE_RESTRICT) {
473 if (ltype == rtype) {
474 ctype = ltype;
475 } else if (lclass & TYPE_FOULED) {
476 if (unfoul(ltype) == rtype)
477 ctype = ltype;
478 } else if (rclass & TYPE_FOULED) {
479 if (unfoul(rtype) == ltype)
480 ctype = rtype;
481 }
482 } else {
483 if (!restricted_value(right, ltype))
484 ctype = ltype;
485 }
486 } else if (!restricted_value(left, rtype))
487 ctype = rtype;
488
489 if (ctype) {
490 switch (restricted_binop(op, ctype)) {
491 case 1:
492 if ((lclass ^ rclass) & TYPE_FOULED)
493 ctype = unfoul(ctype);
494 break;
495 case 3:
496 if (!(lclass & rclass & TYPE_FOULED))
497 break;
498 case 0:
499 ctype = NULL;
500 default:
501 break;
502 }
503 }
504
505 return ctype;
506 }
507
508 static inline void unrestrict(struct expression *expr,
509 int class, struct symbol **ctype)
510 {
511 if (class & TYPE_RESTRICT) {
512 if (class & TYPE_FOULED)
513 *ctype = unfoul(*ctype);
514 warning(expr->pos, "%s degrades to integer",
515 show_typename(*ctype));
516 *ctype = (*ctype)->ctype.base_type; /* get to arithmetic type */
517 }
518 }
519
520 static struct symbol *usual_conversions(int op,
521 struct expression *left,
522 struct expression *right,
523 int lclass, int rclass,
524 struct symbol *ltype,
525 struct symbol *rtype)
526 {
527 struct symbol *ctype;
528
529 warn_for_different_enum_types(right->pos, left->ctype, right->ctype);
530
531 if ((lclass | rclass) & TYPE_RESTRICT)
532 goto Restr;
533
534 Normal:
535 if (!(lclass & TYPE_FLOAT)) {
536 if (!(rclass & TYPE_FLOAT))
537 return bigger_int_type(ltype, rtype);
538 else
539 return rtype;
540 } else if (rclass & TYPE_FLOAT) {
541 if (rtype->rank > ltype->rank)
542 return rtype;
543 else
544 return ltype;
545 } else
546 return ltype;
547
548 Restr:
549 ctype = restricted_binop_type(op, left, right,
550 lclass, rclass, ltype, rtype);
551 if (ctype)
552 return ctype;
553
554 unrestrict(left, lclass, &ltype);
555 unrestrict(right, rclass, &rtype);
556
557 goto Normal;
558 }
559
560 static inline int lvalue_expression(struct expression *expr)
561 {
562 return expr->type == EXPR_PREOP && expr->op == '*';
563 }
564
565 static struct symbol *evaluate_ptr_add(struct expression *expr, struct symbol *itype)
566 {
567 struct expression *index = expr->right;
568 struct symbol *ctype, *base;
569 int multiply;
570
571 classify_type(degenerate(expr->left), &ctype);
572 base = examine_pointer_target(ctype);
573
574 /*
575 * An address constant +/- an integer constant expression
576 * yields an address constant again [6.6(7)].
577 */
578 if ((expr->left->flags & CEF_ADDR) && (expr->right->flags & CEF_ICE))
579 expr->flags = CEF_ADDR;
580
581 if (!base) {
582 expression_error(expr, "missing type information");
583 return NULL;
584 }
585 if (is_function(base)) {
586 expression_error(expr, "arithmetics on pointers to functions");
587 return NULL;
588 }
589
590 /* Get the size of whatever the pointer points to */
591 multiply = is_void_type(base) ? 1 : bits_to_bytes(base->bit_size);
592
593 if (ctype == &null_ctype)
594 ctype = &ptr_ctype;
595 expr->ctype = ctype;
596
597 if (multiply == 1 && itype->bit_size == bits_in_pointer)
598 return ctype;
599
600 if (index->type == EXPR_VALUE) {
601 struct expression *val = alloc_expression(expr->pos, EXPR_VALUE);
602 unsigned long long v = index->value, mask;
603 mask = 1ULL << (itype->bit_size - 1);
604 if (v & mask)
605 v |= -mask;
606 else
607 v &= mask - 1;
608 v *= multiply;
609 mask = 1ULL << (bits_in_pointer - 1);
610 v &= mask | (mask - 1);
611 val->value = v;
612 val->ctype = ssize_t_ctype;
613 expr->right = val;
614 return ctype;
615 }
616
617 if (itype->bit_size != bits_in_pointer)
618 index = cast_to(index, ssize_t_ctype);
619
620 if (multiply > 1) {
621 struct expression *val = alloc_expression(expr->pos, EXPR_VALUE);
622 struct expression *mul = alloc_expression(expr->pos, EXPR_BINOP);
623
624 val->ctype = ssize_t_ctype;
625 val->value = multiply;
626
627 mul->op = '*';
628 mul->ctype = ssize_t_ctype;
629 mul->left = index;
630 mul->right = val;
631 index = mul;
632 }
633
634 expr->right = index;
635 return ctype;
636 }
637
638 static void examine_fn_arguments(struct symbol *fn);
639
640 #define MOD_IGN (MOD_QUALIFIER | MOD_FUN_ATTR)
641
642 const char *type_difference(struct ctype *c1, struct ctype *c2,
643 unsigned long mod1, unsigned long mod2)
644 {
645 struct ident *as1 = c1->as, *as2 = c2->as;
646 struct symbol *t1 = c1->base_type;
647 struct symbol *t2 = c2->base_type;
648 int move1 = 1, move2 = 1;
649 mod1 |= c1->modifiers;
650 mod2 |= c2->modifiers;
651 for (;;) {
652 unsigned long diff;
653 int type;
654 struct symbol *base1 = t1->ctype.base_type;
655 struct symbol *base2 = t2->ctype.base_type;
656
657 /*
658 * FIXME! Collect alignment and context too here!
659 */
660 if (move1) {
661 if (t1 && t1->type != SYM_PTR) {
662 mod1 |= t1->ctype.modifiers;
663 combine_address_space(t1->pos, &as1, t1->ctype.as);
664 }
665 move1 = 0;
666 }
667
668 if (move2) {
669 if (t2 && t2->type != SYM_PTR) {
670 mod2 |= t2->ctype.modifiers;
671 combine_address_space(t2->pos, &as2, t2->ctype.as);
672 }
673 move2 = 0;
674 }
675
676 if (t1 == t2)
677 break;
678 if (!t1 || !t2)
679 return "different types";
680
681 if (t1->type == SYM_NODE || t1->type == SYM_ENUM) {
682 t1 = base1;
683 move1 = 1;
684 if (!t1)
685 return "bad types";
686 continue;
687 }
688
689 if (t2->type == SYM_NODE || t2->type == SYM_ENUM) {
690 t2 = base2;
691 move2 = 1;
692 if (!t2)
693 return "bad types";
694 continue;
695 }
696
697 move1 = move2 = 1;
698 type = t1->type;
699 if (type != t2->type)
700 return "different base types";
701
702 switch (type) {
703 default:
704 sparse_error(t1->pos,
705 "internal error: bad type in derived(%d)",
706 type);
707 return "bad types";
708 case SYM_RESTRICT:
709 return "different base types";
710 case SYM_UNION:
711 case SYM_STRUCT:
712 /* allow definition of incomplete structs and unions */
713 if (t1->ident == t2->ident)
714 return NULL;
715 return "different base types";
716 case SYM_ARRAY:
717 /* XXX: we ought to compare sizes */
718 break;
719 case SYM_PTR:
720 if (as1 != as2)
721 return "different address spaces";
722 /* MOD_SPECIFIER is due to idiocy in parse.c */
723 if ((mod1 ^ mod2) & ~MOD_IGNORE & ~MOD_SPECIFIER)
724 return "different modifiers";
725 /* we could be lazier here */
726 base1 = examine_pointer_target(t1);
727 base2 = examine_pointer_target(t2);
728 mod1 = t1->ctype.modifiers;
729 as1 = t1->ctype.as;
730 mod2 = t2->ctype.modifiers;
731 as2 = t2->ctype.as;
732 break;
733 case SYM_FN: {
734 struct symbol *arg1, *arg2;
735 int i;
736
737 if (as1 != as2)
738 return "different address spaces";
739 if ((mod1 ^ mod2) & ~MOD_IGNORE & ~MOD_SIGNEDNESS)
740 return "different modifiers";
741 mod1 = t1->ctype.modifiers;
742 as1 = t1->ctype.as;
743 mod2 = t2->ctype.modifiers;
744 as2 = t2->ctype.as;
745
746 if (t1->variadic != t2->variadic)
747 return "incompatible variadic arguments";
748 examine_fn_arguments(t1);
749 examine_fn_arguments(t2);
750 PREPARE_PTR_LIST(t1->arguments, arg1);
751 PREPARE_PTR_LIST(t2->arguments, arg2);
752 i = 1;
753 for (;;) {
754 const char *diffstr;
755 if (!arg1 && !arg2)
756 break;
757 if (!arg1 || !arg2)
758 return "different argument counts";
759 diffstr = type_difference(&arg1->ctype,
760 &arg2->ctype,
761 MOD_IGN, MOD_IGN);
762 if (diffstr) {
763 static char argdiff[80];
764 sprintf(argdiff, "incompatible argument %d (%s)", i, diffstr);
765 return argdiff;
766 }
767 NEXT_PTR_LIST(arg1);
768 NEXT_PTR_LIST(arg2);
769 i++;
770 }
771 FINISH_PTR_LIST(arg2);
772 FINISH_PTR_LIST(arg1);
773 break;
774 }
775 case SYM_BASETYPE:
776 if (as1 != as2)
777 return "different address spaces";
778 if (base1 != base2)
779 return "different base types";
780 if (t1->rank != t2->rank)
781 return "different type sizes";
782 diff = (mod1 ^ mod2) & ~MOD_IGNORE;
783 if (!diff)
784 return NULL;
785 else if (diff & ~MOD_SIGNEDNESS)
786 return "different modifiers";
787 else
788 return "different signedness";
789 }
790 t1 = base1;
791 t2 = base2;
792 }
793 if (as1 != as2)
794 return "different address spaces";
795 if ((mod1 ^ mod2) & ~MOD_IGNORE & ~MOD_SIGNEDNESS)
796 return "different modifiers";
797 return NULL;
798 }
799
800 static void bad_null(struct expression *expr)
801 {
802 if (Wnon_pointer_null)
803 warning(expr->pos, "Using plain integer as NULL pointer");
804 }
805
806 static unsigned long target_qualifiers(struct symbol *type)
807 {
808 unsigned long mod = type->ctype.modifiers & MOD_IGN;
809 if (type->ctype.base_type && type->ctype.base_type->type == SYM_ARRAY)
810 mod = 0;
811 return mod;
812 }
813
814 static struct symbol *evaluate_ptr_sub(struct expression *expr)
815 {
816 const char *typediff;
817 struct symbol *ltype, *rtype;
818 struct expression *l = expr->left;
819 struct expression *r = expr->right;
820 struct symbol *lbase;
821
822 classify_type(degenerate(l), &ltype);
823 classify_type(degenerate(r), &rtype);
824
825 lbase = examine_pointer_target(ltype);
826 examine_pointer_target(rtype);
827 typediff = type_difference(&ltype->ctype, &rtype->ctype,
828 target_qualifiers(rtype),
829 target_qualifiers(ltype));
830 if (typediff)
831 expression_error(expr, "subtraction of different types can't work (%s)", typediff);
832
833 if (is_function(lbase)) {
834 expression_error(expr, "subtraction of functions? Share your drugs");
835 return NULL;
836 }
837
838 expr->ctype = ssize_t_ctype;
839 if (lbase->bit_size > bits_in_char) {
840 struct expression *sub = alloc_expression(expr->pos, EXPR_BINOP);
841 struct expression *div = expr;
842 struct expression *val = alloc_expression(expr->pos, EXPR_VALUE);
843 unsigned long value = bits_to_bytes(lbase->bit_size);
844
845 val->ctype = size_t_ctype;
846 val->value = value;
847
848 if (value & (value-1)) {
849 if (Wptr_subtraction_blows) {
850 warning(expr->pos, "potentially expensive pointer subtraction");
851 info(expr->pos, " '%s' has a non-power-of-2 size: %lu", show_typename(lbase), value);
852 }
853 }
854
855 sub->op = '-';
856 sub->ctype = ssize_t_ctype;
857 sub->left = l;
858 sub->right = r;
859
860 div->op = '/';
861 div->left = sub;
862 div->right = val;
863 }
864
865 return ssize_t_ctype;
866 }
867
868 #define is_safe_type(type) ((type)->ctype.modifiers & MOD_SAFE)
869
870 static struct symbol *evaluate_conditional(struct expression *expr, int iterator)
871 {
872 struct symbol *ctype;
873
874 if (!expr)
875 return NULL;
876
877 if (!iterator && expr->type == EXPR_ASSIGNMENT && expr->op == '=')
878 warning(expr->pos, "assignment expression in conditional");
879
880 ctype = evaluate_expression(expr);
881 if (!valid_type(ctype))
882 return NULL;
883 if (is_safe_type(ctype))
884 warning(expr->pos, "testing a 'safe expression'");
885 if (is_func_type(ctype)) {
886 if (Waddress)
887 warning(expr->pos, "the address of %s will always evaluate as true", "a function");
888 } else if (is_array_type(ctype)) {
889 if (Waddress)
890 warning(expr->pos, "the address of %s will always evaluate as true", "an array");
891 } else if (!is_scalar_type(ctype)) {
892 sparse_error(expr->pos, "non-scalar type in conditional:");
893 info(expr->pos, " %s", show_typename(ctype));
894 return NULL;
895 }
896
897 ctype = degenerate(expr);
898 return ctype;
899 }
900
901 static struct symbol *evaluate_logical(struct expression *expr)
902 {
903 if (!evaluate_conditional(expr->left, 0))
904 return NULL;
905 if (!evaluate_conditional(expr->right, 0))
906 return NULL;
907
908 /* the result is int [6.5.13(3), 6.5.14(3)] */
909 expr->ctype = &int_ctype;
910 expr->flags = expr->left->flags & expr->right->flags;
911 expr->flags &= ~(CEF_CONST_MASK | CEF_ADDR);
912 return &int_ctype;
913 }
914
915 static struct symbol *evaluate_binop(struct expression *expr)
916 {
917 struct symbol *ltype, *rtype, *ctype;
918 int lclass = classify_type(expr->left->ctype, &ltype);
919 int rclass = classify_type(expr->right->ctype, &rtype);
920 int op = expr->op;
921
922 /* number op number */
923 if (lclass & rclass & TYPE_NUM) {
924 expr->flags = expr->left->flags & expr->right->flags;
925 expr->flags &= ~CEF_CONST_MASK;
926
927 if ((lclass | rclass) & TYPE_FLOAT) {
928 switch (op) {
929 case '+': case '-': case '*': case '/':
930 break;
931 default:
932 return bad_expr_type(expr);
933 }
934 }
935
936 if (op == SPECIAL_LEFTSHIFT || op == SPECIAL_RIGHTSHIFT) {
937 // shifts do integer promotions, but that's it.
938 unrestrict(expr->left, lclass, &ltype);
939 unrestrict(expr->right, rclass, &rtype);
940 ctype = ltype = integer_promotion(ltype);
941 rtype = integer_promotion(rtype);
942 } else {
943 // The rest do usual conversions
944 const unsigned left_not = expr->left->type == EXPR_PREOP
945 && expr->left->op == '!';
946 const unsigned right_not = expr->right->type == EXPR_PREOP
947 && expr->right->op == '!';
948 if ((op == '&' || op == '|') && (left_not || right_not))
949 warning(expr->pos, "dubious: %sx %c %sy",
950 left_not ? "!" : "",
951 op,
952 right_not ? "!" : "");
953
954 ltype = usual_conversions(op, expr->left, expr->right,
955 lclass, rclass, ltype, rtype);
956 ctype = rtype = ltype;
957 }
958
959 expr->left = cast_to(expr->left, ltype);
960 expr->right = cast_to(expr->right, rtype);
961 expr->ctype = ctype;
962 return ctype;
963 }
964
965 /* pointer (+|-) integer */
966 if (lclass & TYPE_PTR && is_int(rclass) && (op == '+' || op == '-')) {
967 unrestrict(expr->right, rclass, &rtype);
968 return evaluate_ptr_add(expr, rtype);
969 }
970
971 /* integer + pointer */
972 if (rclass & TYPE_PTR && is_int(lclass) && op == '+') {
973 struct expression *index = expr->left;
974 unrestrict(index, lclass, &ltype);
975 expr->left = expr->right;
976 expr->right = index;
977 return evaluate_ptr_add(expr, ltype);
978 }
979
980 /* pointer - pointer */
981 if (lclass & rclass & TYPE_PTR && expr->op == '-')
982 return evaluate_ptr_sub(expr);
983
984 return bad_expr_type(expr);
985 }
986
987 static struct symbol *evaluate_comma(struct expression *expr)
988 {
989 expr->ctype = unqualify_type(degenerate(expr->right));
990 if (expr->ctype == &null_ctype)
991 expr->ctype = &ptr_ctype;
992 expr->flags &= expr->left->flags & expr->right->flags;
993 return expr->ctype;
994 }
995
996 static int modify_for_unsigned(int op)
997 {
998 if (op == '<')
999 op = SPECIAL_UNSIGNED_LT;
1000 else if (op == '>')
1001 op = SPECIAL_UNSIGNED_GT;
1002 else if (op == SPECIAL_LTE)
1003 op = SPECIAL_UNSIGNED_LTE;
1004 else if (op == SPECIAL_GTE)
1005 op = SPECIAL_UNSIGNED_GTE;
1006 return op;
1007 }
1008
1009 enum null_constant_type {
1010 NON_NULL,
1011 NULL_PTR,
1012 NULL_ZERO,
1013 };
1014
1015 static inline int is_null_pointer_constant(struct expression *e)
1016 {
1017 if (e->ctype == &null_ctype)
1018 return NULL_PTR;
1019 if (!(e->flags & CEF_ICE))
1020 return NON_NULL;
1021 return is_zero_constant(e) ? NULL_ZERO : NON_NULL;
1022 }
1023
1024 static struct symbol *evaluate_compare(struct expression *expr)
1025 {
1026 struct expression *left = expr->left, *right = expr->right;
1027 struct symbol *ltype, *rtype, *lbase, *rbase;
1028 int lclass = classify_type(degenerate(left), &ltype);
1029 int rclass = classify_type(degenerate(right), &rtype);
1030 struct symbol *ctype;
1031 const char *typediff;
1032
1033 /* Type types? */
1034 if (is_type_type(ltype) && is_type_type(rtype)) {
1035 /*
1036 * __builtin_types_compatible_p() yields an integer
1037 * constant expression
1038 */
1039 expr->flags = CEF_SET_ICE;
1040 goto OK;
1041 }
1042
1043 if (is_safe_type(left->ctype) || is_safe_type(right->ctype))
1044 warning(expr->pos, "testing a 'safe expression'");
1045
1046 expr->flags = left->flags & right->flags & ~CEF_CONST_MASK & ~CEF_ADDR;
1047
1048 /* number on number */
1049 if (lclass & rclass & TYPE_NUM) {
1050 ctype = usual_conversions(expr->op, expr->left, expr->right,
1051 lclass, rclass, ltype, rtype);
1052 expr->left = cast_to(expr->left, ctype);
1053 expr->right = cast_to(expr->right, ctype);
1054 if (ctype->ctype.modifiers & MOD_UNSIGNED)
1055 expr->op = modify_for_unsigned(expr->op);
1056 goto OK;
1057 }
1058
1059 /* at least one must be a pointer */
1060 if (!((lclass | rclass) & TYPE_PTR))
1061 return bad_expr_type(expr);
1062
1063 /* equality comparisons can be with null pointer constants */
1064 if (expr->op == SPECIAL_EQUAL || expr->op == SPECIAL_NOTEQUAL) {
1065 int is_null1 = is_null_pointer_constant(left);
1066 int is_null2 = is_null_pointer_constant(right);
1067 if (is_null1 == NULL_ZERO)
1068 bad_null(left);
1069 if (is_null2 == NULL_ZERO)
1070 bad_null(right);
1071 if (is_null1 && is_null2) {
1072 int positive = expr->op == SPECIAL_EQUAL;
1073 expr->type = EXPR_VALUE;
1074 expr->value = positive;
1075 goto OK;
1076 }
1077 if (is_null1 && (rclass & TYPE_PTR)) {
1078 expr->left = cast_to(left, rtype);
1079 goto OK;
1080 }
1081 if (is_null2 && (lclass & TYPE_PTR)) {
1082 expr->right = cast_to(right, ltype);
1083 goto OK;
1084 }
1085 }
1086 /* both should be pointers */
1087 if (!(lclass & rclass & TYPE_PTR))
1088 return bad_expr_type(expr);
1089 expr->op = modify_for_unsigned(expr->op);
1090
1091 lbase = examine_pointer_target(ltype);
1092 rbase = examine_pointer_target(rtype);
1093
1094 /* they also have special treatment for pointers to void */
1095 if (expr->op == SPECIAL_EQUAL || expr->op == SPECIAL_NOTEQUAL) {
1096 if (ltype->ctype.as == rtype->ctype.as) {
1097 if (lbase == &void_ctype) {
1098 expr->right = cast_to(right, ltype);
1099 goto OK;
1100 }
1101 if (rbase == &void_ctype) {
1102 expr->left = cast_to(left, rtype);
1103 goto OK;
1104 }
1105 }
1106 }
1107
1108 typediff = type_difference(&ltype->ctype, &rtype->ctype,
1109 target_qualifiers(rtype),
1110 target_qualifiers(ltype));
1111 if (!typediff)
1112 goto OK;
1113
1114 expression_error(expr, "incompatible types in comparison expression (%s):", typediff);
1115 info(expr->pos, " %s", show_typename(ltype));
1116 info(expr->pos, " %s", show_typename(rtype));
1117 return NULL;
1118
1119 OK:
1120 /* the result is int [6.5.8(6), 6.5.9(3)]*/
1121 expr->ctype = &int_ctype;
1122 return &int_ctype;
1123 }
1124
1125 /*
1126 * NOTE! The degenerate case of "x ? : y", where we don't
1127 * have a true case, this will possibly promote "x" to the
1128 * same type as "y", and thus _change_ the conditional
1129 * test in the expression. But since promotion is "safe"
1130 * for testing, that's OK.
1131 */
1132 static struct symbol *evaluate_conditional_expression(struct expression *expr)
1133 {
1134 struct expression **cond;
1135 struct symbol *ctype, *ltype, *rtype, *lbase, *rbase;
1136 int lclass, rclass;
1137 const char * typediff;
1138 int qual;
1139
1140 if (!evaluate_conditional(expr->conditional, 0))
1141 return NULL;
1142 if (!evaluate_expression(expr->cond_false))
1143 return NULL;
1144
1145 ctype = degenerate(expr->conditional);
1146 rtype = degenerate(expr->cond_false);
1147
1148 cond = &expr->conditional;
1149 ltype = ctype;
1150 if (expr->cond_true) {
1151 if (!evaluate_expression(expr->cond_true))
1152 return NULL;
1153 ltype = degenerate(expr->cond_true);
1154 cond = &expr->cond_true;
1155 }
1156
1157 expr->flags = (expr->conditional->flags & (*cond)->flags &
1158 expr->cond_false->flags & ~CEF_CONST_MASK);
1159 /*
1160 * In the standard, it is defined that an integer constant expression
1161 * shall only have operands that are themselves constant [6.6(6)].
1162 * While this definition is very clear for expressions that need all
1163 * their operands to be evaluated, for conditional expressions with a
1164 * constant condition things are much less obvious.
1165 * So, as an extension, do the same as GCC seems to do:
1166 * Consider a conditional expression with a constant condition
1167 * as having the same constantness as the argument corresponding
1168 * to the truth value (including in the case of address constants
1169 * which are defined more stricly [6.6(9)]).
1170 */
1171 if (expr->conditional->flags & (CEF_ACE | CEF_ADDR)) {
1172 int is_true = expr_truth_value(expr->conditional);
1173 struct expression *arg = is_true ? *cond : expr->cond_false;
1174 expr->flags = arg->flags & ~CEF_CONST_MASK;
1175 }
1176
1177 lclass = classify_type(ltype, &ltype);
1178 rclass = classify_type(rtype, &rtype);
1179 if (lclass & rclass & TYPE_NUM) {
1180 ctype = usual_conversions('?', *cond, expr->cond_false,
1181 lclass, rclass, ltype, rtype);
1182 *cond = cast_to(*cond, ctype);
1183 expr->cond_false = cast_to(expr->cond_false, ctype);
1184 goto out;
1185 }
1186
1187 if ((lclass | rclass) & TYPE_PTR) {
1188 int is_null1 = is_null_pointer_constant(*cond);
1189 int is_null2 = is_null_pointer_constant(expr->cond_false);
1190
1191 if (is_null1 && is_null2) {
1192 *cond = cast_to(*cond, &ptr_ctype);
1193 expr->cond_false = cast_to(expr->cond_false, &ptr_ctype);
1194 ctype = &ptr_ctype;
1195 goto out;
1196 }
1197 if (is_null1 && (rclass & TYPE_PTR)) {
1198 if (is_null1 == NULL_ZERO)
1199 bad_null(*cond);
1200 *cond = cast_to(*cond, rtype);
1201 ctype = rtype;
1202 goto out;
1203 }
1204 if (is_null2 && (lclass & TYPE_PTR)) {
1205 if (is_null2 == NULL_ZERO)
1206 bad_null(expr->cond_false);
1207 expr->cond_false = cast_to(expr->cond_false, ltype);
1208 ctype = ltype;
1209 goto out;
1210 }
1211 if (!(lclass & rclass & TYPE_PTR)) {
1212 typediff = "different types";
1213 goto Err;
1214 }
1215 /* OK, it's pointer on pointer */
1216 if (ltype->ctype.as != rtype->ctype.as) {
1217 typediff = "different address spaces";
1218 goto Err;
1219 }
1220
1221 /* need to be lazier here */
1222 lbase = examine_pointer_target(ltype);
1223 rbase = examine_pointer_target(rtype);
1224 qual = target_qualifiers(ltype) | target_qualifiers(rtype);
1225
1226 if (lbase == &void_ctype) {
1227 /* XXX: pointers to function should warn here */
1228 ctype = ltype;
1229 goto Qual;
1230
1231 }
1232 if (rbase == &void_ctype) {
1233 /* XXX: pointers to function should warn here */
1234 ctype = rtype;
1235 goto Qual;
1236 }
1237 /* XXX: that should be pointer to composite */
1238 ctype = ltype;
1239 typediff = type_difference(&ltype->ctype, &rtype->ctype,
1240 qual, qual);
1241 if (!typediff)
1242 goto Qual;
1243 goto Err;
1244 }
1245
1246 /* void on void, struct on same struct, union on same union */
1247 if (ltype == rtype) {
1248 ctype = ltype;
1249 goto out;
1250 }
1251 typediff = "different base types";
1252
1253 Err:
1254 expression_error(expr, "incompatible types in conditional expression (%s):", typediff);
1255 info(expr->pos, " %s", show_typename(ltype));
1256 info(expr->pos, " %s", show_typename(rtype));
1257 /*
1258 * if the condition is constant, the type is in fact known
1259 * so use it, as gcc & clang do.
1260 */
1261 switch (expr_truth_value(expr->conditional)) {
1262 case 1: expr->ctype = ltype;
1263 break;
1264 case 0: expr->ctype = rtype;
1265 break;
1266 default:
1267 break;
1268 }
1269 return NULL;
1270
1271 out:
1272 expr->ctype = ctype;
1273 return ctype;
1274
1275 Qual:
1276 if (qual & ~ctype->ctype.modifiers) {
1277 struct symbol *sym = alloc_symbol(ctype->pos, SYM_PTR);
1278 *sym = *ctype;
1279 sym->ctype.modifiers |= qual;
1280 ctype = sym;
1281 }
1282 *cond = cast_to(*cond, ctype);
1283 expr->cond_false = cast_to(expr->cond_false, ctype);
1284 goto out;
1285 }
1286
1287 /* FP assignments can not do modulo or bit operations */
1288 static int compatible_float_op(int op)
1289 {
1290 return op == SPECIAL_ADD_ASSIGN ||
1291 op == SPECIAL_SUB_ASSIGN ||
1292 op == SPECIAL_MUL_ASSIGN ||
1293 op == SPECIAL_DIV_ASSIGN;
1294 }
1295
1296 static int evaluate_assign_op(struct expression *expr)
1297 {
1298 struct symbol *target = expr->left->ctype;
1299 struct symbol *source = expr->right->ctype;
1300 struct symbol *t, *s;
1301 int tclass = classify_type(target, &t);
1302 int sclass = classify_type(source, &s);
1303 int op = expr->op;
1304
1305 if (tclass & sclass & TYPE_NUM) {
1306 if (tclass & TYPE_FLOAT && !compatible_float_op(op)) {
1307 expression_error(expr, "invalid assignment");
1308 return 0;
1309 }
1310 if (tclass & TYPE_RESTRICT) {
1311 if (!restricted_binop(op, t)) {
1312 warning(expr->pos, "bad assignment (%s) to %s",
1313 show_special(op), show_typename(t));
1314 expr->right = cast_to(expr->right, target);
1315 return 0;
1316 }
1317 /* allowed assignments unfoul */
1318 if (sclass & TYPE_FOULED && unfoul(s) == t)
1319 goto Cast;
1320 if (!restricted_value(expr->right, t))
1321 return 1;
1322 } else if (op == SPECIAL_SHR_ASSIGN || op == SPECIAL_SHL_ASSIGN) {
1323 // shifts do integer promotions, but that's it.
1324 unrestrict(expr->left, tclass, &t);
1325 target = integer_promotion(t);
1326
1327 unrestrict(expr->right, sclass, &s);
1328 source = integer_promotion(s);
1329 expr->right = cast_to(expr->right, source);
1330
1331 // both gcc & clang seems to do this, so ...
1332 if (target->bit_size > source->bit_size)
1333 expr->right = cast_to(expr->right, &uint_ctype);
1334
1335 goto Cast;
1336 } else if (!(sclass & TYPE_RESTRICT))
1337 goto usual;
1338 /* source and target would better be identical restricted */
1339 if (t == s)
1340 return 1;
1341 warning(expr->pos, "invalid assignment: %s", show_special(op));
1342 info(expr->pos, " left side has type %s", show_typename(t));
1343 info(expr->pos, " right side has type %s", show_typename(s));
1344 expr->right = cast_to(expr->right, target);
1345 return 0;
1346 }
1347 if (tclass == TYPE_PTR && is_int(sclass)) {
1348 if (op == SPECIAL_ADD_ASSIGN || op == SPECIAL_SUB_ASSIGN) {
1349 unrestrict(expr->right, sclass, &s);
1350 evaluate_ptr_add(expr, s);
1351 return 1;
1352 }
1353 expression_error(expr, "invalid pointer assignment");
1354 return 0;
1355 }
1356
1357 expression_error(expr, "invalid assignment");
1358 return 0;
1359
1360 usual:
1361 target = usual_conversions(op, expr->left, expr->right,
1362 tclass, sclass, target, source);
1363 Cast:
1364 expr->right = cast_to(expr->right, target);
1365 return 1;
1366 }
1367
1368 static int whitelist_pointers(struct symbol *t1, struct symbol *t2)
1369 {
1370 if (t1 == t2)
1371 return 0; /* yes, 0 - we don't want a cast_to here */
1372 if (t1 == &void_ctype)
1373 return 1;
1374 if (t2 == &void_ctype)
1375 return 1;
1376 if (classify_type(t1, &t1) != TYPE_NUM)
1377 return 0;
1378 if (classify_type(t2, &t2) != TYPE_NUM)
1379 return 0;
1380 if (t1 == t2)
1381 return 1;
1382 if (t1->rank == -2 && t2->rank == -2)
1383 return 1;
1384 if (t1->rank != t2->rank)
1385 return 0;
1386 return !Wtypesign;
1387 }
1388
1389 static int check_assignment_types(struct symbol *target, struct expression **rp,
1390 const char **typediff)
1391 {
1392 struct symbol *source = degenerate(*rp);
1393 struct symbol *t, *s;
1394 int tclass = classify_type(target, &t);
1395 int sclass = classify_type(source, &s);
1396
1397 if (tclass & sclass & TYPE_NUM) {
1398 if (tclass & TYPE_RESTRICT) {
1399 /* allowed assignments unfoul */
1400 if (sclass & TYPE_FOULED && unfoul(s) == t)
1401 goto Cast;
1402 if (!restricted_value(*rp, target))
1403 goto Cast;
1404 if (s == t)
1405 return 1;
1406 } else if (!(sclass & TYPE_RESTRICT))
1407 goto Cast;
1408 if (t == &bool_ctype) {
1409 if (is_fouled_type(s))
1410 warning((*rp)->pos, "%s degrades to integer",
1411 show_typename(s->ctype.base_type));
1412 goto Cast;
1413 }
1414 *typediff = "different base types";
1415 return 0;
1416 }
1417
1418 if (tclass == TYPE_PTR) {
1419 unsigned long mod1, mod2;
1420 unsigned long modl, modr;
1421 struct symbol *b1, *b2;
1422 // NULL pointer is always OK
1423 int is_null = is_null_pointer_constant(*rp);
1424 if (is_null) {
1425 if (is_null == NULL_ZERO)
1426 bad_null(*rp);
1427 goto Cast;
1428 }
1429 if (!(sclass & TYPE_PTR)) {
1430 *typediff = "different base types";
1431 return 0;
1432 }
1433 b1 = examine_pointer_target(t);
1434 b2 = examine_pointer_target(s);
1435 mod1 = t->ctype.modifiers & MOD_IGN;
1436 mod2 = s->ctype.modifiers & MOD_IGN;
1437 if (whitelist_pointers(b1, b2)) {
1438 /*
1439 * assignments to/from void * are OK, provided that
1440 * we do not remove qualifiers from pointed to [C]
1441 * or mix address spaces [sparse].
1442 */
1443 if (t->ctype.as != s->ctype.as) {
1444 *typediff = "different address spaces";
1445 return 0;
1446 }
1447 /*
1448 * If this is a function pointer assignment, it is
1449 * actually fine to assign a pointer to const data to
1450 * it, as a function pointer points to const data
1451 * implicitly, i.e., dereferencing it does not produce
1452 * an lvalue.
1453 */
1454 if (b1->type == SYM_FN)
1455 mod1 |= MOD_CONST;
1456 if (mod2 & ~mod1 & ~MOD_FUN_ATTR) {
1457 *typediff = "different modifiers";
1458 return 0;
1459 }
1460 goto Cast;
1461 }
1462 /* It's OK if the target is more volatile or const than the source */
1463 /* It's OK if the source is more pure/noreturn than the target */
1464 modr = mod1 & ~MOD_REV_QUAL;
1465 modl = mod2 & MOD_REV_QUAL;
1466 *typediff = type_difference(&t->ctype, &s->ctype, modl, modr);
1467 if (*typediff)
1468 return 0;
1469 return 1;
1470 }
1471
1472 if ((tclass & TYPE_COMPOUND) && s == t)
1473 return 1;
1474
1475 if (tclass & TYPE_NUM) {
1476 /* XXX: need to turn into comparison with NULL */
1477 if (t == &bool_ctype && (sclass & TYPE_PTR))
1478 goto Cast;
1479 *typediff = "different base types";
1480 return 0;
1481 }
1482 *typediff = "invalid types";
1483 return 0;
1484
1485 Cast:
1486 *rp = cast_to(*rp, target);
1487 return 1;
1488 }
1489
1490 static int compatible_assignment_types(struct expression *expr, struct symbol *target,
1491 struct expression **rp, const char *where)
1492 {
1493 const char *typediff;
1494
1495 if (!check_assignment_types(target, rp, &typediff)) {
1496 struct symbol *source = *rp ? (*rp)->ctype : NULL;
1497 warning(expr->pos, "incorrect type in %s (%s)", where, typediff);
1498 info(expr->pos, " expected %s", show_typename(target));
1499 info(expr->pos, " got %s", show_typename(source));
1500 *rp = cast_to(*rp, target);
1501 return 0;
1502 }
1503
1504 return 1;
1505 }
1506
1507 static int compatible_transparent_union(struct symbol *target,
1508 struct expression **rp)
1509 {
1510 struct symbol *t, *member;
1511 classify_type(target, &t);
1512 if (t->type != SYM_UNION || !t->transparent_union)
1513 return 0;
1514
1515 FOR_EACH_PTR(t->symbol_list, member) {
1516 const char *typediff;
1517 if (check_assignment_types(member, rp, &typediff))
1518 return 1;
1519 } END_FOR_EACH_PTR(member);
1520
1521 return 0;
1522 }
1523
1524 static int compatible_argument_type(struct expression *expr, struct symbol *target,
1525 struct expression **rp, const char *where)
1526 {
1527 if (compatible_transparent_union(target, rp))
1528 return 1;
1529
1530 return compatible_assignment_types(expr, target, rp, where);
1531 }
1532
1533 static void mark_addressable(struct expression *expr)
1534 {
1535 while (expr->type == EXPR_BINOP && expr->op == '+')
1536 expr = expr->left;
1537 if (expr->type == EXPR_SYMBOL) {
1538 struct symbol *sym = expr->symbol;
1539 sym->ctype.modifiers |= MOD_ADDRESSABLE;
1540 }
1541 }
1542
1543 static void mark_assigned(struct expression *expr)
1544 {
1545 struct symbol *sym;
1546
1547 if (!expr)
1548 return;
1549 switch (expr->type) {
1550 case EXPR_SYMBOL:
1551 sym = expr->symbol;
1552 if (!sym)
1553 return;
1554 if (sym->type != SYM_NODE)
1555 return;
1556 sym->ctype.modifiers |= MOD_ASSIGNED;
1557 return;
1558
1559 case EXPR_BINOP:
1560 mark_assigned(expr->left);
1561 mark_assigned(expr->right);
1562 return;
1563 case EXPR_CAST:
1564 case EXPR_FORCE_CAST:
1565 mark_assigned(expr->cast_expression);
1566 return;
1567 case EXPR_SLICE:
1568 mark_assigned(expr->base);
1569 return;
1570 default:
1571 /* Hmm? */
1572 return;
1573 }
1574 }
1575
1576 static void evaluate_assign_to(struct expression *left, struct symbol *type)
1577 {
1578 if (type->ctype.modifiers & MOD_CONST)
1579 expression_error(left, "assignment to const expression");
1580
1581 /* We know left is an lvalue, so it's a "preop-*" */
1582 mark_assigned(left->unop);
1583 }
1584
1585 static struct symbol *evaluate_assignment(struct expression *expr)
1586 {
1587 struct expression *left = expr->left;
1588 struct symbol *ltype;
1589
1590 if (!lvalue_expression(left)) {
1591 expression_error(expr, "not an lvalue");
1592 return NULL;
1593 }
1594
1595 ltype = left->ctype;
1596
1597 if (expr->op != '=') {
1598 if (!evaluate_assign_op(expr))
1599 return NULL;
1600 } else {
1601 if (!compatible_assignment_types(expr, ltype, &expr->right, "assignment"))
1602 return NULL;
1603 }
1604
1605 evaluate_assign_to(left, ltype);
1606
1607 expr->ctype = ltype;
1608 return ltype;
1609 }
1610
1611 static void examine_fn_arguments(struct symbol *fn)
1612 {
1613 struct symbol *s;
1614
1615 FOR_EACH_PTR(fn->arguments, s) {
1616 struct symbol *arg = evaluate_symbol(s);
1617 /* Array/function arguments silently degenerate into pointers */
1618 if (arg) {
1619 struct symbol *ptr;
1620 switch(arg->type) {
1621 case SYM_ARRAY:
1622 case SYM_FN:
1623 ptr = alloc_symbol(s->pos, SYM_PTR);
1624 if (arg->type == SYM_ARRAY)
1625 ptr->ctype = arg->ctype;
1626 else
1627 ptr->ctype.base_type = arg;
1628 combine_address_space(s->pos, &ptr->ctype.as, s->ctype.as);
1629 ptr->ctype.modifiers |= s->ctype.modifiers & MOD_PTRINHERIT;
1630
1631 s->ctype.base_type = ptr;
1632 s->ctype.as = NULL;
1633 s->ctype.modifiers &= ~MOD_PTRINHERIT;
1634 s->bit_size = 0;
1635 s->examined = 0;
1636 examine_symbol_type(s);
1637 break;
1638 default:
1639 /* nothing */
1640 break;
1641 }
1642 }
1643 } END_FOR_EACH_PTR(s);
1644 }
1645
1646 static struct symbol *convert_to_as_mod(struct symbol *sym, struct ident *as, int mod)
1647 {
1648 /* Take the modifiers of the pointer, and apply them to the member */
1649 mod |= sym->ctype.modifiers;
1650 if (sym->ctype.as != as || sym->ctype.modifiers != mod) {
1651 struct symbol *newsym = alloc_symbol(sym->pos, SYM_NODE);
1652 *newsym = *sym;
1653 newsym->ctype.as = as;
1654 newsym->ctype.modifiers = mod;
1655 sym = newsym;
1656 }
1657 return sym;
1658 }
1659
1660 static struct symbol *create_pointer(struct expression *expr, struct symbol *sym, int degenerate)
1661 {
1662 struct symbol *node = alloc_symbol(expr->pos, SYM_NODE);
1663 struct symbol *ptr = alloc_symbol(expr->pos, SYM_PTR);
1664
1665 node->ctype.base_type = ptr;
1666 ptr->bit_size = bits_in_pointer;
1667 ptr->ctype.alignment = pointer_alignment;
1668
1669 node->bit_size = bits_in_pointer;
1670 node->ctype.alignment = pointer_alignment;
1671
1672 access_symbol(sym);
1673 if (sym->ctype.modifiers & MOD_REGISTER) {
1674 warning(expr->pos, "taking address of 'register' variable '%s'", show_ident(sym->ident));
1675 sym->ctype.modifiers &= ~MOD_REGISTER;
1676 }
1677 if (sym->type == SYM_NODE) {
1678 combine_address_space(sym->pos, &ptr->ctype.as, sym->ctype.as);
1679 ptr->ctype.modifiers |= sym->ctype.modifiers & MOD_PTRINHERIT;
1680 sym = sym->ctype.base_type;
1681 }
1682 if (degenerate && sym->type == SYM_ARRAY) {
1683 combine_address_space(sym->pos, &ptr->ctype.as, sym->ctype.as);
1684 ptr->ctype.modifiers |= sym->ctype.modifiers & MOD_PTRINHERIT;
1685 sym = sym->ctype.base_type;
1686 }
1687 ptr->ctype.base_type = sym;
1688
1689 return node;
1690 }
1691
1692 /* Arrays degenerate into pointers on pointer arithmetic */
1693 static struct symbol *degenerate(struct expression *expr)
1694 {
1695 struct symbol *ctype, *base;
1696
1697 if (!expr)
1698 return NULL;
1699 ctype = expr->ctype;
1700 if (!ctype)
1701 return NULL;
1702 base = examine_symbol_type(ctype);
1703 if (ctype->type == SYM_NODE)
1704 base = ctype->ctype.base_type;
1705 /*
1706 * Arrays degenerate into pointers to the entries, while
1707 * functions degenerate into pointers to themselves.
1708 * If array was part of non-lvalue compound, we create a copy
1709 * of that compound first and then act as if we were dealing with
1710 * the corresponding field in there.
1711 */
1712 switch (base->type) {
1713 case SYM_ARRAY:
1714 if (expr->type == EXPR_SLICE) {
1715 struct symbol *a = alloc_symbol(expr->pos, SYM_NODE);
1716 struct expression *e0, *e1, *e2, *e3, *e4;
1717
1718 a->ctype.base_type = expr->base->ctype;
1719 a->bit_size = expr->base->ctype->bit_size;
1720 a->array_size = expr->base->ctype->array_size;
1721
1722 e0 = alloc_expression(expr->pos, EXPR_SYMBOL);
1723 e0->symbol = a;
1724 e0->ctype = &lazy_ptr_ctype;
1725
1726 e1 = alloc_expression(expr->pos, EXPR_PREOP);
1727 e1->unop = e0;
1728 e1->op = '*';
1729 e1->ctype = expr->base->ctype; /* XXX */
1730
1731 e2 = alloc_expression(expr->pos, EXPR_ASSIGNMENT);
1732 e2->left = e1;
1733 e2->right = expr->base;
1734 e2->op = '=';
1735 e2->ctype = expr->base->ctype;
1736
1737 if (expr->r_bitpos) {
1738 e3 = alloc_expression(expr->pos, EXPR_BINOP);
1739 e3->op = '+';
1740 e3->left = e0;
1741 e3->right = alloc_const_expression(expr->pos,
1742 bits_to_bytes(expr->r_bitpos));
1743 e3->ctype = &lazy_ptr_ctype;
1744 } else {
1745 e3 = e0;
1746 }
1747
1748 e4 = alloc_expression(expr->pos, EXPR_COMMA);
1749 e4->left = e2;
1750 e4->right = e3;
1751 e4->ctype = &lazy_ptr_ctype;
1752
1753 expr->unop = e4;
1754 expr->type = EXPR_PREOP;
1755 expr->op = '*';
1756 }
1757 case SYM_FN:
1758 if (expr->op != '*' || expr->type != EXPR_PREOP) {
1759 expression_error(expr, "strange non-value function or array");
1760 return &bad_ctype;
1761 }
1762 if (ctype->builtin)
1763 sparse_error(expr->pos, "taking the address of built-in function '%s'", show_ident(ctype->ident));
1764 *expr = *expr->unop;
1765 ctype = create_pointer(expr, ctype, 1);
1766 expr->ctype = ctype;
1767 mark_addressable(expr);
1768 default:
1769 /* nothing */;
1770 }
1771 return ctype;
1772 }
1773
1774 static struct symbol *evaluate_addressof(struct expression *expr)
1775 {
1776 struct expression *op = expr->unop;
1777 struct symbol *ctype;
1778
1779 if (op->op != '*' || op->type != EXPR_PREOP) {
1780 expression_error(expr, "not addressable");
1781 return NULL;
1782 }
1783 ctype = op->ctype;
1784 if (ctype->builtin)
1785 sparse_error(expr->pos, "taking the address of built-in function '%s'", show_ident(ctype->ident));
1786 *expr = *op->unop;
1787
1788 mark_addressable(expr);
1789
1790 /*
1791 * symbol expression evaluation is lazy about the type
1792 * of the sub-expression, so we may have to generate
1793 * the type here if so..
1794 */
1795 if (expr->ctype == &lazy_ptr_ctype) {
1796 ctype = create_pointer(expr, ctype, 0);
1797 expr->ctype = ctype;
1798 }
1799 return expr->ctype;
1800 }
1801
1802
1803 static struct symbol *evaluate_dereference(struct expression *expr)
1804 {
1805 struct expression *op = expr->unop;
1806 struct symbol *ctype = op->ctype, *node, *target;
1807
1808 /* Simplify: *&(expr) => (expr) */
1809 if (op->type == EXPR_PREOP && op->op == '&') {
1810 *expr = *op->unop;
1811 expr->flags = CEF_NONE;
1812 return expr->ctype;
1813 }
1814
1815 examine_symbol_type(ctype);
1816
1817 /* Dereferencing a node drops all the node information. */
1818 if (ctype->type == SYM_NODE)
1819 ctype = ctype->ctype.base_type;
1820
1821 target = ctype->ctype.base_type;
1822
1823 switch (ctype->type) {
1824 default:
1825 expression_error(expr, "cannot dereference this type");
1826 return NULL;
1827 case SYM_FN:
1828 *expr = *op;
1829 return expr->ctype;
1830 case SYM_PTR:
1831 examine_symbol_type(target);
1832 node = alloc_symbol(expr->pos, SYM_NODE);
1833 node->ctype.modifiers = target->ctype.modifiers & MOD_SPECIFIER;
1834 merge_type(node, ctype);
1835 break;
1836
1837 case SYM_ARRAY:
1838 if (!lvalue_expression(op)) {
1839 expression_error(op, "non-lvalue array??");
1840 return NULL;
1841 }
1842
1843 /* Do the implied "addressof" on the array */
1844 *op = *op->unop;
1845
1846 /*
1847 * When an array is dereferenced, we need to pick
1848 * up the attributes of the original node too..
1849 */
1850 node = alloc_symbol(expr->pos, SYM_NODE);
1851 merge_type(node, op->ctype);
1852 merge_type(node, ctype);
1853 break;
1854 }
1855
1856 node->bit_size = target->bit_size;
1857 node->array_size = target->array_size;
1858
1859 expr->ctype = node;
1860 return node;
1861 }
1862
1863 /*
1864 * Unary post-ops: x++ and x--
1865 */
1866 static struct symbol *evaluate_postop(struct expression *expr)
1867 {
1868 struct expression *op = expr->unop;
1869 struct symbol *ctype = op->ctype;
1870 int class = classify_type(ctype, &ctype);
1871 int multiply = 0;
1872
1873 if (!class || class & TYPE_COMPOUND) {
1874 expression_error(expr, "need scalar for ++/--");
1875 return NULL;
1876 }
1877 if (!lvalue_expression(expr->unop)) {
1878 expression_error(expr, "need lvalue expression for ++/--");
1879 return NULL;
1880 }
1881
1882 unrestrict(expr, class, &ctype);
1883
1884 if (class & TYPE_NUM) {
1885 multiply = 1;
1886 } else if (class == TYPE_PTR) {
1887 struct symbol *target = examine_pointer_target(ctype);
1888 if (!is_function(target))
1889 multiply = bits_to_bytes(target->bit_size);
1890 }
1891
1892 if (multiply) {
1893 evaluate_assign_to(op, op->ctype);
1894 expr->op_value = multiply;
1895 expr->ctype = ctype;
1896 return ctype;
1897 }
1898
1899 expression_error(expr, "bad argument type for ++/--");
1900 return NULL;
1901 }
1902
1903 static struct symbol *evaluate_sign(struct expression *expr)
1904 {
1905 struct symbol *ctype = expr->unop->ctype;
1906 int class = classify_type(ctype, &ctype);
1907 unsigned char flags = expr->unop->flags & ~CEF_CONST_MASK;
1908
1909 /* should be an arithmetic type */
1910 if (!(class & TYPE_NUM))
1911 return bad_expr_type(expr);
1912 if (class & TYPE_RESTRICT)
1913 goto Restr;
1914 Normal:
1915 if (!(class & TYPE_FLOAT)) {
1916 ctype = integer_promotion(ctype);
1917 expr->unop = cast_to(expr->unop, ctype);
1918 } else if (expr->op != '~') {
1919 /* no conversions needed */
1920 } else {
1921 return bad_expr_type(expr);
1922 }
1923 if (expr->op == '+')
1924 *expr = *expr->unop;
1925 expr->flags = flags;
1926 expr->ctype = ctype;
1927 return ctype;
1928 Restr:
1929 if (restricted_unop(expr->op, &ctype))
1930 unrestrict(expr, class, &ctype);
1931 goto Normal;
1932 }
1933
1934 static struct symbol *evaluate_preop(struct expression *expr)
1935 {
1936 struct symbol *ctype = expr->unop->ctype;
1937
1938 switch (expr->op) {
1939 case '(':
1940 *expr = *expr->unop;
1941 return ctype;
1942
1943 case '+':
1944 case '-':
1945 case '~':
1946 return evaluate_sign(expr);
1947
1948 case '*':
1949 return evaluate_dereference(expr);
1950
1951 case '&':
1952 return evaluate_addressof(expr);
1953
1954 case SPECIAL_INCREMENT:
1955 case SPECIAL_DECREMENT:
1956 /*
1957 * From a type evaluation standpoint the preops are
1958 * the same as the postops
1959 */
1960 return evaluate_postop(expr);
1961
1962 case '!':
1963 ctype = degenerate(expr->unop);
1964 expr->flags = expr->unop->flags & ~CEF_CONST_MASK;
1965 /*
1966 * A logical negation never yields an address constant
1967 * [6.6(9)].
1968 */
1969 expr->flags &= ~CEF_ADDR;
1970
1971 if (is_safe_type(ctype))
1972 warning(expr->pos, "testing a 'safe expression'");
1973 if (is_float_type(ctype)) {
1974 struct expression *arg = expr->unop;
1975 expr->type = EXPR_COMPARE;
1976 expr->op = SPECIAL_EQUAL;
1977 expr->left = arg;
1978 expr->right = alloc_expression(expr->pos, EXPR_FVALUE);
1979 expr->right->ctype = ctype;
1980 expr->right->fvalue = 0;
1981 } else if (is_fouled_type(ctype)) {
1982 warning(expr->pos, "%s degrades to integer",
1983 show_typename(ctype->ctype.base_type));
1984 }
1985 /* the result is int [6.5.3.3(5)]*/
1986 ctype = &int_ctype;
1987 break;
1988
1989 default:
1990 break;
1991 }
1992 expr->ctype = ctype;
1993 return ctype;
1994 }
1995
1996 struct symbol *find_identifier(struct ident *ident, struct symbol_list *_list, int *offset)
1997 {
1998 struct ptr_list *head = (struct ptr_list *)_list;
1999 struct ptr_list *list = head;
2000
2001 if (!head)
2002 return NULL;
2003 do {
2004 int i;
2005 for (i = 0; i < list->nr; i++) {
2006 struct symbol *sym = (struct symbol *) list->list[i];
2007 if (sym->ident) {
2008 if (sym->ident != ident)
2009 continue;
2010 *offset = sym->offset;
2011 return sym;
2012 } else {
2013 struct symbol *ctype = sym->ctype.base_type;
2014 struct symbol *sub;
2015 if (!ctype)
2016 continue;
2017 if (ctype->type != SYM_UNION && ctype->type != SYM_STRUCT)
2018 continue;
2019 sub = find_identifier(ident, ctype->symbol_list, offset);
2020 if (!sub)
2021 continue;
2022 *offset += sym->offset;
2023 return sub;
2024 }
2025 }
2026 } while ((list = list->next) != head);
2027 return NULL;
2028 }
2029
2030 static struct expression *evaluate_offset(struct expression *expr, unsigned long offset)
2031 {
2032 struct expression *add;
2033
2034 /*
2035 * Create a new add-expression
2036 *
2037 * NOTE! Even if we just add zero, we need a new node
2038 * for the member pointer, since it has a different
2039 * type than the original pointer. We could make that
2040 * be just a cast, but the fact is, a node is a node,
2041 * so we might as well just do the "add zero" here.
2042 */
2043 add = alloc_expression(expr->pos, EXPR_BINOP);
2044 add->op = '+';
2045 add->left = expr;
2046 add->right = alloc_expression(expr->pos, EXPR_VALUE);
2047 add->right->ctype = &int_ctype;
2048 add->right->value = offset;
2049
2050 /*
2051 * The ctype of the pointer will be lazily evaluated if
2052 * we ever take the address of this member dereference..
2053 */
2054 add->ctype = &lazy_ptr_ctype;
2055 /*
2056 * The resulting address of a member access through an address
2057 * constant is an address constant again [6.6(9)].
2058 */
2059 add->flags = expr->flags;
2060
2061 return add;
2062 }
2063
2064 /* structure/union dereference */
2065 static struct symbol *evaluate_member_dereference(struct expression *expr)
2066 {
2067 int offset;
2068 struct symbol *ctype, *member;
2069 struct expression *deref = expr->deref, *add;
2070 struct ident *ident = expr->member;
2071 struct ident *address_space;
2072 unsigned int mod;
2073
2074 if (!evaluate_expression(deref))
2075 return NULL;
2076 if (!ident) {
2077 expression_error(expr, "bad member name");
2078 return NULL;
2079 }
2080
2081 ctype = deref->ctype;
2082 examine_symbol_type(ctype);
2083 address_space = ctype->ctype.as;
2084 mod = ctype->ctype.modifiers;
2085 if (ctype->type == SYM_NODE) {
2086 ctype = ctype->ctype.base_type;
2087 combine_address_space(deref->pos, &address_space, ctype->ctype.as);
2088 mod |= ctype->ctype.modifiers;
2089 }
2090 if (!ctype || (ctype->type != SYM_STRUCT && ctype->type != SYM_UNION)) {
2091 expression_error(expr, "expected structure or union");
2092 return NULL;
2093 }
2094 offset = 0;
2095 member = find_identifier(ident, ctype->symbol_list, &offset);
2096 if (!member) {
2097 const char *type = ctype->type == SYM_STRUCT ? "struct" : "union";
2098 const char *name = "<unnamed>";
2099 int namelen = 9;
2100 if (ctype->ident) {
2101 name = ctype->ident->name;
2102 namelen = ctype->ident->len;
2103 }
2104 if (ctype->symbol_list)
2105 expression_error(expr, "no member '%s' in %s %.*s",
2106 show_ident(ident), type, namelen, name);
2107 else
2108 expression_error(expr, "using member '%s' in "
2109 "incomplete %s %.*s", show_ident(ident),
2110 type, namelen, name);
2111 return NULL;
2112 }
2113
2114 /*
2115 * The member needs to take on the address space and modifiers of
2116 * the "parent" type.
2117 */
2118 member = convert_to_as_mod(member, address_space, mod);
2119 ctype = get_base_type(member);
2120
2121 if (!lvalue_expression(deref)) {
2122 if (deref->type != EXPR_SLICE) {
2123 expr->base = deref;
2124 expr->r_bitpos = 0;
2125 } else {
2126 expr->base = deref->base;
2127 expr->r_bitpos = deref->r_bitpos;
2128 }
2129 expr->r_bitpos += bytes_to_bits(offset);
2130 expr->type = EXPR_SLICE;
2131 expr->r_bitpos += member->bit_offset;
2132 expr->ctype = member;
2133 return member;
2134 }
2135
2136 deref = deref->unop;
2137 expr->deref = deref;
2138
2139 add = evaluate_offset(deref, offset);
2140 expr->type = EXPR_PREOP;
2141 expr->op = '*';
2142 expr->unop = add;
2143
2144 expr->ctype = member;
2145 return member;
2146 }
2147
2148 static int is_promoted(struct expression *expr)
2149 {
2150 while (1) {
2151 switch (expr->type) {
2152 case EXPR_BINOP:
2153 case EXPR_SELECT:
2154 case EXPR_CONDITIONAL:
2155 return 1;
2156 case EXPR_COMMA:
2157 expr = expr->right;
2158 continue;
2159 case EXPR_PREOP:
2160 switch (expr->op) {
2161 case '(':
2162 expr = expr->unop;
2163 continue;
2164 case '+':
2165 case '-':
2166 case '~':
2167 return 1;
2168 default:
2169 return 0;
2170 }
2171 default:
2172 return 0;
2173 }
2174 }
2175 }
2176
2177
2178 static struct symbol *evaluate_type_information(struct expression *expr)
2179 {
2180 struct symbol *sym = expr->cast_type;
2181 if (!sym) {
2182 sym = evaluate_expression(expr->cast_expression);
2183 if (!sym)
2184 return NULL;
2185 /*
2186 * Expressions of restricted types will possibly get
2187 * promoted - check that here
2188 */
2189 if (is_restricted_type(sym)) {
2190 if (sym->bit_size < bits_in_int && is_promoted(expr))
2191 sym = &int_ctype;
2192 } else if (is_fouled_type(sym)) {
2193 sym = &int_ctype;
2194 }
2195 }
2196 examine_symbol_type(sym);
2197 if (is_bitfield_type(sym)) {
2198 expression_error(expr, "trying to examine bitfield type");
2199 return NULL;
2200 }
2201 return sym;
2202 }
2203
2204 static struct symbol *evaluate_sizeof(struct expression *expr)
2205 {
2206 struct symbol *type;
2207 int size;
2208
2209 type = evaluate_type_information(expr);
2210 if (!type)
2211 return NULL;
2212
2213 size = type->bit_size;
2214
2215 if (size < 0 && is_void_type(type)) {
2216 if (Wpointer_arith)
2217 warning(expr->pos, "expression using sizeof(void)");
2218 size = bits_in_char;
2219 }
2220
2221 if (is_bool_type(type)) {
2222 if (Wsizeof_bool)
2223 warning(expr->pos, "expression using sizeof _Bool");
2224 size = bits_to_bytes(bits_in_bool) * bits_in_char;
2225 }
2226
2227 if (is_function(type->ctype.base_type)) {
2228 if (Wpointer_arith)
2229 warning(expr->pos, "expression using sizeof on a function");
2230 size = bits_in_char;
2231 }
2232
2233 if (has_flexible_array(type) && Wflexible_array_sizeof)
2234 warning(expr->pos, "using sizeof on a flexible structure");
2235
2236 if (is_array_type(type) && size < 0) { // VLA, 1-dimension only
2237 struct expression *base, *size;
2238 struct symbol *base_type;
2239
2240 if (type->type == SYM_NODE)
2241 type = type->ctype.base_type; // strip the SYM_NODE
2242 base_type = get_base_type(type);
2243 if (!base_type)
2244 goto error;
2245 if (base_type->bit_size <= 0) {
2246 base = alloc_expression(expr->pos, EXPR_SIZEOF);
2247 base->cast_type = base_type;
2248 if (!evaluate_sizeof(base))
2249 goto error;
2250 } else {
2251 base = alloc_expression(expr->pos, EXPR_VALUE);
2252 base->value = bits_to_bytes(base_type->bit_size);
2253 base->ctype = size_t_ctype;
2254 }
2255 size = alloc_expression(expr->pos, EXPR_CAST);
2256 size->cast_type = size_t_ctype;
2257 size->cast_expression = type->array_size;
2258 if (!evaluate_expression(size))
2259 goto error;
2260 expr->left = size;
2261 expr->right = base;
2262 expr->type = EXPR_BINOP;
2263 expr->op = '*';
2264 return expr->ctype = size_t_ctype;
2265 }
2266
2267 error:
2268 if ((size < 0) || (size & (bits_in_char - 1)))
2269 expression_error(expr, "cannot size expression");
2270
2271 expr->type = EXPR_VALUE;
2272 expr->value = bits_to_bytes(size);
2273 expr->taint = 0;
2274 expr->ctype = size_t_ctype;
2275 return size_t_ctype;
2276 }
2277
2278 static struct symbol *evaluate_ptrsizeof(struct expression *expr)
2279 {
2280 struct symbol *type;
2281 int size;
2282
2283 type = evaluate_type_information(expr);
2284 if (!type)
2285 return NULL;
2286
2287 if (type->type == SYM_NODE)
2288 type = type->ctype.base_type;
2289 if (!type)
2290 return NULL;
2291 switch (type->type) {
2292 case SYM_ARRAY:
2293 break;
2294 case SYM_PTR:
2295 type = get_base_type(type);
2296 if (type)
2297 break;
2298 default:
2299 expression_error(expr, "expected pointer expression");
2300 return NULL;
2301 }
2302 size = type->bit_size;
2303 if (size & (bits_in_char-1))
2304 size = 0;
2305 expr->type = EXPR_VALUE;
2306 expr->value = bits_to_bytes(size);
2307 expr->taint = 0;
2308 expr->ctype = size_t_ctype;
2309 return size_t_ctype;
2310 }
2311
2312 static struct symbol *evaluate_alignof(struct expression *expr)
2313 {
2314 struct symbol *type;
2315
2316 type = evaluate_type_information(expr);
2317 if (!type)
2318 return NULL;
2319
2320 expr->type = EXPR_VALUE;
2321 expr->value = type->ctype.alignment;
2322 expr->taint = 0;
2323 expr->ctype = size_t_ctype;
2324 return size_t_ctype;
2325 }
2326
2327 int evaluate_arguments(struct symbol_list *argtypes, struct expression_list *head)
2328 {
2329 struct expression *expr;
2330 struct symbol *argtype;
2331 int i = 1;
2332
2333 PREPARE_PTR_LIST(argtypes, argtype);
2334 FOR_EACH_PTR (head, expr) {
2335 struct expression **p = THIS_ADDRESS(expr);
2336 struct symbol *ctype, *target;
2337 ctype = evaluate_expression(expr);
2338
2339 if (!ctype)
2340 return 0;
2341
2342 target = argtype;
2343 if (!target) {
2344 struct symbol *type;
2345 int class = classify_type(ctype, &type);
2346 if (is_int(class)) {
2347 *p = cast_to(expr, integer_promotion(type));
2348 } else if (class & TYPE_FLOAT) {
2349 if (type->rank < 0)
2350 *p = cast_to(expr, &double_ctype);
2351 } else if (class & TYPE_PTR) {
2352 if (expr->ctype == &null_ctype)
2353 *p = cast_to(expr, &ptr_ctype);
2354 else
2355 degenerate(expr);
2356 }
2357 } else if (!target->forced_arg){
2358 static char where[30];
2359 examine_symbol_type(target);
2360 sprintf(where, "argument %d", i);
2361 compatible_argument_type(expr, target, p, where);
2362 }
2363
2364 i++;
2365 NEXT_PTR_LIST(argtype);
2366 } END_FOR_EACH_PTR(expr);
2367 FINISH_PTR_LIST(argtype);
2368 return 1;
2369 }
2370
2371 static void convert_index(struct expression *e)
2372 {
2373 struct expression *child = e->idx_expression;
2374 unsigned from = e->idx_from;
2375 unsigned to = e->idx_to + 1;
2376 e->type = EXPR_POS;
2377 e->init_offset = from * bits_to_bytes(e->ctype->bit_size);
2378 e->init_nr = to - from;
2379 e->init_expr = child;
2380 }
2381
2382 static void convert_ident(struct expression *e)
2383 {
2384 struct expression *child = e->ident_expression;
2385 int offset = e->offset;
2386
2387 e->type = EXPR_POS;
2388 e->init_offset = offset;
2389 e->init_nr = 1;
2390 e->init_expr = child;
2391 }
2392
2393 static void convert_designators(struct expression *e)
2394 {
2395 while (e) {
2396 if (e->type == EXPR_INDEX)
2397 convert_index(e);
2398 else if (e->type == EXPR_IDENTIFIER)
2399 convert_ident(e);
2400 else
2401 break;
2402 e = e->init_expr;
2403 }
2404 }
2405
2406 static void excess(struct expression *e, const char *s)
2407 {
2408 warning(e->pos, "excessive elements in %s initializer", s);
2409 }
2410
2411 /*
2412 * implicit designator for the first element
2413 */
2414 static struct expression *first_subobject(struct symbol *ctype, int class,
2415 struct expression **v)
2416 {
2417 struct expression *e = *v, *new;
2418
2419 if (ctype->type == SYM_NODE)
2420 ctype = ctype->ctype.base_type;
2421
2422 if (class & TYPE_PTR) { /* array */
2423 if (!ctype->bit_size)
2424 return NULL;
2425 new = alloc_expression(e->pos, EXPR_INDEX);
2426 new->idx_expression = e;
2427 new->ctype = ctype->ctype.base_type;
2428 } else {
2429 struct symbol *field, *p;
2430 PREPARE_PTR_LIST(ctype->symbol_list, p);
2431 while (p && !p->ident && is_bitfield_type(p))
2432 NEXT_PTR_LIST(p);
2433 field = p;
2434 FINISH_PTR_LIST(p);
2435 if (!field)
2436 return NULL;
2437 new = alloc_expression(e->pos, EXPR_IDENTIFIER);
2438 new->ident_expression = e;
2439 new->field = new->ctype = field;
2440 new->offset = field->offset;
2441 }
2442 *v = new;
2443 return new;
2444 }
2445
2446 /*
2447 * sanity-check explicit designators; return the innermost one or NULL
2448 * in case of error. Assign types.
2449 */
2450 static struct expression *check_designators(struct expression *e,
2451 struct symbol *ctype)
2452 {
2453 struct expression *last = NULL;
2454 const char *err;
2455 while (1) {
2456 if (ctype->type == SYM_NODE)
2457 ctype = ctype->ctype.base_type;
2458 if (e->type == EXPR_INDEX) {
2459 struct symbol *type;
2460 if (ctype->type != SYM_ARRAY) {
2461 err = "array index in non-array";
2462 break;
2463 }
2464 type = ctype->ctype.base_type;
2465 if (ctype->bit_size >= 0 && type->bit_size >= 0) {
2466 unsigned offset = array_element_offset(type->bit_size, e->idx_to);
2467 if (offset >= ctype->bit_size) {
2468 err = "index out of bounds in";
2469 break;
2470 }
2471 }
2472 e->ctype = ctype = type;
2473 ctype = type;
2474 last = e;
2475 if (!e->idx_expression) {
2476 err = "invalid";
2477 break;
2478 }
2479 e = e->idx_expression;
2480 } else if (e->type == EXPR_IDENTIFIER) {
2481 int offset = 0;
2482 if (ctype->type != SYM_STRUCT && ctype->type != SYM_UNION) {
2483 err = "field name not in struct or union";
2484 break;
2485 }
2486 ctype = find_identifier(e->expr_ident, ctype->symbol_list, &offset);
2487 if (!ctype) {
2488 err = "unknown field name in";
2489 break;
2490 }
2491 e->offset = offset;
2492 e->field = e->ctype = ctype;
2493 last = e;
2494 if (!e->ident_expression) {
2495 err = "invalid";
2496 break;
2497 }
2498 e = e->ident_expression;
2499 } else if (e->type == EXPR_POS) {
2500 err = "internal front-end error: EXPR_POS in";
2501 break;
2502 } else
2503 return last;
2504 }
2505 expression_error(e, "%s initializer", err);
2506 return NULL;
2507 }
2508
2509 /*
2510 * choose the next subobject to initialize.
2511 *
2512 * Get designators for next element, switch old ones to EXPR_POS.
2513 * Return the resulting expression or NULL if we'd run out of subobjects.
2514 * The innermost designator is returned in *v. Designators in old
2515 * are assumed to be already sanity-checked.
2516 */
2517 static struct expression *next_designators(struct expression *old,
2518 struct symbol *ctype,
2519 struct expression *e, struct expression **v)
2520 {
2521 struct expression *new = NULL;
2522
2523 if (!old)
2524 return NULL;
2525 if (old->type == EXPR_INDEX) {
2526 struct expression *copy;
2527 unsigned n;
2528
2529 copy = next_designators(old->idx_expression,
2530 old->ctype, e, v);
2531 if (!copy) {
2532 n = old->idx_to + 1;
2533 if (array_element_offset(old->ctype->bit_size, n) == ctype->bit_size) {
2534 convert_index(old);
2535 return NULL;
2536 }
2537 copy = e;
2538 *v = new = alloc_expression(e->pos, EXPR_INDEX);
2539 } else {
2540 n = old->idx_to;
2541 new = alloc_expression(e->pos, EXPR_INDEX);
2542 }
2543
2544 new->idx_from = new->idx_to = n;
2545 new->idx_expression = copy;
2546 new->ctype = old->ctype;
2547 convert_index(old);
2548 } else if (old->type == EXPR_IDENTIFIER) {
2549 struct expression *copy;
2550 struct symbol *field;
2551 int offset = 0;
2552
2553 copy = next_designators(old->ident_expression,
2554 old->ctype, e, v);
2555 if (!copy) {
2556 field = old->field->next_subobject;
2557 if (!field) {
2558 convert_ident(old);
2559 return NULL;
2560 }
2561 copy = e;
2562 *v = new = alloc_expression(e->pos, EXPR_IDENTIFIER);
2563 /*
2564 * We can't necessarily trust "field->offset",
2565 * because the field might be in an anonymous
2566 * union, and the field offset is then the offset
2567 * within that union.
2568 *
2569 * The "old->offset - old->field->offset"
2570 * would be the offset of such an anonymous
2571 * union.
2572 */
2573 offset = old->offset - old->field->offset;
2574 } else {
2575 field = old->field;
2576 new = alloc_expression(e->pos, EXPR_IDENTIFIER);
2577 }
2578
2579 new->field = field;
2580 new->expr_ident = field->ident;
2581 new->ident_expression = copy;
2582 new->ctype = field;
2583 new->offset = field->offset + offset;
2584 convert_ident(old);
2585 }
2586 return new;
2587 }
2588
2589 static int handle_initializer(struct expression **ep, int nested,
2590 int class, struct symbol *ctype, unsigned long mods);
2591
2592 /*
2593 * deal with traversing subobjects [6.7.8(17,18,20)]
2594 */
2595 static void handle_list_initializer(struct expression *expr,
2596 int class, struct symbol *ctype, unsigned long mods)
2597 {
2598 struct expression *e, *last = NULL, *top = NULL, *next;
2599 int jumped = 0; // has the last designator multiple levels?
2600
2601 if (expr->zero_init)
2602 free_ptr_list(&expr->expr_list);
2603
2604 FOR_EACH_PTR(expr->expr_list, e) {
2605 struct expression **v;
2606 struct symbol *type;
2607 int lclass;
2608
2609 if (e->type != EXPR_INDEX && e->type != EXPR_IDENTIFIER) {
2610 struct symbol *struct_sym;
2611 if (!top) {
2612 top = e;
2613 last = first_subobject(ctype, class, &top);
2614 } else {
2615 last = next_designators(last, ctype, e, &top);
2616 }
2617 if (!last) {
2618 excess(e, class & TYPE_PTR ? "array" :
2619 "struct or union");
2620 DELETE_CURRENT_PTR(e);
2621 continue;
2622 }
2623 struct_sym = ctype->type == SYM_NODE ? ctype->ctype.base_type : ctype;
2624 if (Wdesignated_init && struct_sym->designated_init)
2625 warning(e->pos, "%s%.*s%spositional init of field in %s %s, declared with attribute designated_init",
2626 ctype->ident ? "in initializer for " : "",
2627 ctype->ident ? ctype->ident->len : 0,
2628 ctype->ident ? ctype->ident->name : "",
2629 ctype->ident ? ": " : "",
2630 get_type_name(struct_sym->type),
2631 show_ident(struct_sym->ident));
2632 if (jumped && Wpast_deep_designator) {
2633 warning(e->pos, "advancing past deep designator");
2634 jumped = 0;
2635 }
2636 REPLACE_CURRENT_PTR(e, last);
2637 } else {
2638 next = check_designators(e, ctype);
2639 if (!next) {
2640 DELETE_CURRENT_PTR(e);
2641 continue;
2642 }
2643 top = next;
2644 /* deeper than one designator? */
2645 jumped = top != e;
2646 convert_designators(last);
2647 last = e;
2648 }
2649
2650 found:
2651 lclass = classify_type(top->ctype, &type);
2652 if (top->type == EXPR_INDEX)
2653 v = &top->idx_expression;
2654 else
2655 v = &top->ident_expression;
2656
2657 mods |= ctype->ctype.modifiers & MOD_STORAGE;
2658 if (handle_initializer(v, 1, lclass, top->ctype, mods))
2659 continue;
2660
2661 if (!(lclass & TYPE_COMPOUND)) {
2662 warning(e->pos, "bogus scalar initializer");
2663 DELETE_CURRENT_PTR(e);
2664 continue;
2665 }
2666
2667 next = first_subobject(type, lclass, v);
2668 if (next) {
2669 warning(e->pos, "missing braces around initializer");
2670 top = next;
2671 goto found;
2672 }
2673
2674 DELETE_CURRENT_PTR(e);
2675 excess(e, lclass & TYPE_PTR ? "array" : "struct or union");
2676
2677 } END_FOR_EACH_PTR(e);
2678
2679 convert_designators(last);
2680 expr->ctype = ctype;
2681 }
2682
2683 static int is_string_literal(struct expression **v)
2684 {
2685 struct expression *e = *v;
2686 while (e && e->type == EXPR_PREOP && e->op == '(')
2687 e = e->unop;
2688 if (!e || e->type != EXPR_STRING)
2689 return 0;
2690 if (e != *v && Wparen_string)
2691 warning(e->pos,
2692 "array initialized from parenthesized string constant");
2693 *v = e;
2694 return 1;
2695 }
2696
2697 /*
2698 * We want a normal expression, possibly in one layer of braces. Warn
2699 * if the latter happens inside a list (it's legal, but likely to be
2700 * an effect of screwup). In case of anything not legal, we are definitely
2701 * having an effect of screwup, so just fail and let the caller warn.
2702 */
2703 static struct expression *handle_scalar(struct expression *e, int nested)
2704 {
2705 struct expression *v = NULL, *p;
2706 int count = 0;
2707
2708 /* normal case */
2709 if (e->type != EXPR_INITIALIZER)
2710 return e;
2711
2712 FOR_EACH_PTR(e->expr_list, p) {
2713 if (!v)
2714 v = p;
2715 count++;
2716 } END_FOR_EACH_PTR(p);
2717 if (count != 1)
2718 return NULL;
2719 switch(v->type) {
2720 case EXPR_INITIALIZER:
2721 case EXPR_INDEX:
2722 case EXPR_IDENTIFIER:
2723 return NULL;
2724 default:
2725 break;
2726 }
2727 if (nested)
2728 warning(e->pos, "braces around scalar initializer");
2729 return v;
2730 }
2731
2732 /*
2733 * deal with the cases that don't care about subobjects:
2734 * scalar <- assignment expression, possibly in braces [6.7.8(11)]
2735 * character array <- string literal, possibly in braces [6.7.8(14)]
2736 * struct or union <- assignment expression of compatible type [6.7.8(13)]
2737 * compound type <- initializer list in braces [6.7.8(16)]
2738 * The last one punts to handle_list_initializer() which, in turn will call
2739 * us for individual elements of the list.
2740 *
2741 * We do not handle 6.7.8(15) (wide char array <- wide string literal) for
2742 * the lack of support of wide char stuff in general.
2743 *
2744 * One note: we need to take care not to evaluate a string literal until
2745 * we know that we *will* handle it right here. Otherwise we would screw
2746 * the cases like struct { struct {char s[10]; ...} ...} initialized with
2747 * { "string", ...} - we need to preserve that string literal recognizable
2748 * until we dig into the inner struct.
2749 */
2750 static int handle_initializer(struct expression **ep, int nested,
2751 int class, struct symbol *ctype, unsigned long mods)
2752 {
2753 struct expression *e = *ep, *p;
2754 struct symbol *type;
2755
2756 if (!e)
2757 return 0;
2758
2759 /* scalar */
2760 if (!(class & TYPE_COMPOUND)) {
2761 e = handle_scalar(e, nested);
2762 if (!e)
2763 return 0;
2764 *ep = e;
2765 if (!evaluate_expression(e))
2766 return 1;
2767 compatible_assignment_types(e, ctype, ep, "initializer");
2768 /*
2769 * Initializers for static storage duration objects
2770 * shall be constant expressions or a string literal [6.7.8(4)].
2771 */
2772 mods |= ctype->ctype.modifiers;
2773 mods &= (MOD_TOPLEVEL | MOD_STATIC);
2774 if (mods && !(e->flags & (CEF_ACE | CEF_ADDR)))
2775 if (Wconstexpr_not_const)
2776 warning(e->pos, "non-constant initializer for static object");
2777
2778 return 1;
2779 }
2780
2781 /*
2782 * sublist; either a string, or we dig in; the latter will deal with
2783 * pathologies, so we don't need anything fancy here.
2784 */
2785 if (e->type == EXPR_INITIALIZER) {
2786 if (is_string_type(ctype)) {
2787 struct expression *v = NULL;
2788 int count = 0;
2789
2790 FOR_EACH_PTR(e->expr_list, p) {
2791 if (!v)
2792 v = p;
2793 count++;
2794 } END_FOR_EACH_PTR(p);
2795 if (count == 1 && is_string_literal(&v)) {
2796 *ep = e = v;
2797 goto String;
2798 }
2799 }
2800 handle_list_initializer(e, class, ctype, mods);
2801 return 1;
2802 }
2803
2804 /* string */
2805 if (is_string_literal(&e)) {
2806 /* either we are doing array of char, or we'll have to dig in */
2807 if (is_string_type(ctype)) {
2808 *ep = e;
2809 goto String;
2810 }
2811 return 0;
2812 }
2813 /* struct or union can be initialized by compatible */
2814 if (class != TYPE_COMPOUND)
2815 return 0;
2816 type = evaluate_expression(e);
2817 if (!type)
2818 return 0;
2819 if (ctype->type == SYM_NODE)
2820 ctype = ctype->ctype.base_type;
2821 if (type->type == SYM_NODE)
2822 type = type->ctype.base_type;
2823 if (ctype == type)
2824 return 1;
2825 return 0;
2826
2827 String:
2828 p = alloc_expression(e->pos, EXPR_STRING);
2829 *p = *e;
2830 type = evaluate_expression(p);
2831 if (ctype->bit_size != -1) {
2832 struct symbol *char_type = e->wide ? wchar_ctype : &char_ctype;
2833 unsigned int size_with_null = ctype->bit_size + char_type->bit_size;
2834 if (size_with_null < type->bit_size)
2835 warning(e->pos,
2836 "too long initializer-string for array of char");
2837 else if (Winit_cstring && size_with_null == type->bit_size) {
2838 warning(e->pos,
2839 "too long initializer-string for array of char(no space for nul char)");
2840 }
2841 }
2842 *ep = p;
2843 return 1;
2844 }
2845
2846 static void evaluate_initializer(struct symbol *ctype, struct expression **ep)
2847 {
2848 struct symbol *type;
2849 int class = classify_type(ctype, &type);
2850 if (!handle_initializer(ep, 0, class, ctype, 0))
2851 expression_error(*ep, "invalid initializer");
2852 }
2853
2854 static struct symbol *cast_to_bool(struct expression *expr)
2855 {
2856 struct expression *old = expr->cast_expression;
2857 struct expression *zero;
2858 struct symbol *otype;
2859 int oclass = classify_type(degenerate(old), &otype);
2860 struct symbol *ctype;
2861
2862 if (oclass & TYPE_COMPOUND)
2863 return NULL;
2864
2865 zero = alloc_const_expression(expr->pos, 0);
2866 if (oclass & TYPE_PTR)
2867 zero->ctype = otype;
2868 expr->op = SPECIAL_NOTEQUAL;
2869 ctype = usual_conversions(expr->op, old, zero,
2870 oclass, TYPE_NUM, otype, zero->ctype);
2871 expr->type = EXPR_COMPARE;
2872 expr->left = cast_to(old, ctype);
2873 expr->right = cast_to(zero, ctype);
2874
2875 return expr->ctype;
2876 }
2877
2878 static int cast_flags(struct expression *expr, struct expression *old)
2879 {
2880 struct symbol *t;
2881 int class;
2882 int flags = CEF_NONE;
2883
2884 class = classify_type(expr->ctype, &t);
2885 if (class & TYPE_NUM) {
2886 flags = old->flags & ~CEF_CONST_MASK;
2887 /*
2888 * Casts to numeric types never result in address
2889 * constants [6.6(9)].
2890 */
2891 flags &= ~CEF_ADDR;
2892
2893 /*
2894 * As an extension, treat address constants cast to
2895 * integer type as an arithmetic constant.
2896 */
2897 if (old->flags & CEF_ADDR)
2898 flags = CEF_ACE;
2899
2900 /*
2901 * Cast to float type -> not an integer constant
2902 * expression [6.6(6)].
2903 */
2904 if (class & TYPE_FLOAT)
2905 flags &= ~CEF_CLR_ICE;
2906 /*
2907 * Casts of float literals to integer type results in
2908 * a constant integer expression [6.6(6)].
2909 */
2910 else if (old->flags & CEF_FLOAT)
2911 flags = CEF_SET_ICE;
2912 } else if (class & TYPE_PTR) {
2913 /*
2914 * Casts of integer literals to pointer type yield
2915 * address constants [6.6(9)].
2916 *
2917 * As an extension, treat address constants cast to a
2918 * different pointer type as address constants again.
2919 *
2920 * As another extension, treat integer constant
2921 * expressions (in contrast to literals) cast to
2922 * pointer type as address constants.
2923 */
2924 if (old->flags & (CEF_ICE | CEF_ADDR))
2925 flags = CEF_ADDR;
2926 }
2927
2928 return flags;
2929 }
2930
2931 ///
2932 // check if a type matches one of the members of a union type
2933 // @utype: the union type
2934 // @type: to type to check
2935 // @return: to identifier of the matching type in the union.
2936 static struct symbol *find_member_type(struct symbol *utype, struct symbol *type)
2937 {
2938 struct symbol *t, *member;
2939
2940 if (utype->type != SYM_UNION)
2941 return NULL;
2942
2943 FOR_EACH_PTR(utype->symbol_list, member) {
2944 classify_type(member, &t);
2945 if (type == t)
2946 return member;
2947 } END_FOR_EACH_PTR(member);
2948 return NULL;
2949 }
2950
2951 static struct symbol *evaluate_compound_literal(struct expression *expr, struct expression *source)
2952 {
2953 struct expression *addr = alloc_expression(expr->pos, EXPR_SYMBOL);
2954 struct symbol *sym = expr->cast_type;
2955
2956 sym->initializer = source;
2957 evaluate_symbol(sym);
2958
2959 addr->ctype = &lazy_ptr_ctype; /* Lazy eval */
2960 addr->symbol = sym;
2961 if (sym->ctype.modifiers & MOD_TOPLEVEL)
2962 addr->flags |= CEF_ADDR;
2963
2964 expr->type = EXPR_PREOP;
2965 expr->op = '*';
2966 expr->deref = addr;
2967 expr->ctype = sym;
2968 return sym;
2969 }
2970
2971 static struct symbol *evaluate_cast(struct expression *expr)
2972 {
2973 struct expression *source = expr->cast_expression;
2974 struct symbol *ctype;
2975 struct symbol *ttype, *stype;
2976 struct symbol *member;
2977 int tclass, sclass;
2978 struct ident *tas = NULL, *sas = NULL;
2979
2980 if (!source)
2981 return NULL;
2982
2983 /*
2984 * Special case: a cast can be followed by an
2985 * initializer, in which case we need to pass
2986 * the type value down to that initializer rather
2987 * than trying to evaluate it as an expression
2988 * (cfr. compound literals: C99 & C11 6.5.2.5).
2989 *
2990 * A more complex case is when the initializer is
2991 * dereferenced as part of a post-fix expression.
2992 * We need to produce an expression that can be dereferenced.
2993 */
2994 if (source->type == EXPR_INITIALIZER)
2995 return evaluate_compound_literal(expr, source);
2996
2997 ctype = examine_symbol_type(expr->cast_type);
2998 ctype = unqualify_type(ctype);
2999 expr->ctype = ctype;
3000 expr->cast_type = ctype;
3001
3002 evaluate_expression(source);
3003 degenerate(source);
3004
3005 tclass = classify_type(ctype, &ttype);
3006
3007 expr->flags = cast_flags(expr, source);
3008
3009 /*
3010 * You can always throw a value away by casting to
3011 * "void" - that's an implicit "force". Note that
3012 * the same is _not_ true of "void *".
3013 */
3014 if (ttype == &void_ctype)
3015 goto out;
3016
3017 stype = source->ctype;
3018 if (!stype) {
3019 expression_error(expr, "cast from unknown type");
3020 goto out;
3021 }
3022 sclass = classify_type(stype, &stype);
3023
3024 if (expr->type == EXPR_FORCE_CAST)
3025 goto out;
3026
3027 if (tclass & (TYPE_COMPOUND | TYPE_FN)) {
3028 /*
3029 * Special case: cast to union type (GCC extension)
3030 * The effect is similar to a compound literal except
3031 * that the result is a rvalue.
3032 */
3033 if ((member = find_member_type(ttype, stype))) {
3034 struct expression *item, *init;
3035
3036 if (Wunion_cast)
3037 warning(expr->pos, "cast to union type");
3038
3039 item = alloc_expression(source->pos, EXPR_IDENTIFIER);
3040 item->expr_ident = member->ident;
3041 item->ident_expression = source;
3042
3043 init = alloc_expression(source->pos, EXPR_INITIALIZER);
3044 add_expression(&init->expr_list, item);
3045
3046 // FIXME: this should be a rvalue
3047 evaluate_compound_literal(expr, init);
3048 return ctype;
3049 }
3050
3051 warning(expr->pos, "cast to non-scalar");
3052 }
3053
3054 if (sclass & TYPE_COMPOUND)
3055 warning(expr->pos, "cast from non-scalar");
3056
3057 /* allowed cast unfouls */
3058 if (sclass & TYPE_FOULED)
3059 stype = unfoul(stype);
3060
3061 if (ttype != stype) {
3062 if ((tclass & TYPE_RESTRICT) && restricted_value(source, ttype))
3063 warning(expr->pos, "cast to %s",
3064 show_typename(ttype));
3065 if (sclass & TYPE_RESTRICT) {
3066 if (ttype == &bool_ctype) {
3067 if (sclass & TYPE_FOULED)
3068 warning(expr->pos, "%s degrades to integer",
3069 show_typename(stype));
3070 } else {
3071 warning(expr->pos, "cast from %s",
3072 show_typename(stype));
3073 }
3074 }
3075 }
3076
3077 if ((ttype == &ulong_ctype || ttype == uintptr_ctype) && !Wcast_from_as)
3078 tas = &bad_address_space;
3079 else if (tclass == TYPE_PTR) {
3080 examine_pointer_target(ttype);
3081 tas = ttype->ctype.as;
3082 }
3083
3084 if ((stype == &ulong_ctype || stype == uintptr_ctype))
3085 sas = &bad_address_space;
3086 else if (sclass == TYPE_PTR) {
3087 examine_pointer_target(stype);
3088 sas = stype->ctype.as;
3089 }
3090
3091 if (!tas && valid_as(sas))
3092 warning(expr->pos, "cast removes address space '%s' of expression", show_as(sas));
3093 if (valid_as(tas) && valid_as(sas) && tas != sas)
3094 warning(expr->pos, "cast between address spaces (%s -> %s)", show_as(sas), show_as(tas));
3095 if (valid_as(tas) && !sas &&
3096 !is_null_pointer_constant(source) && Wcast_to_as)
3097 warning(expr->pos,
3098 "cast adds address space '%s' to expression", show_as(tas));
3099
3100 if (!(ttype->ctype.modifiers & MOD_PTRINHERIT) && tclass == TYPE_PTR &&
3101 !tas && (source->flags & CEF_ICE)) {
3102 if (ttype->ctype.base_type == &void_ctype) {
3103 if (is_zero_constant(source)) {
3104 /* NULL */
3105 expr->type = EXPR_VALUE;
3106 expr->ctype = &null_ctype;
3107 expr->value = 0;
3108 return expr->ctype;
3109 }
3110 }
3111 }
3112
3113 if (ttype == &bool_ctype)
3114 cast_to_bool(expr);
3115
3116 // checks pointers to restricted
3117 while (Wbitwise_pointer && tclass == TYPE_PTR && sclass == TYPE_PTR) {
3118 tclass = classify_type(ttype->ctype.base_type, &ttype);
3119 sclass = classify_type(stype->ctype.base_type, &stype);
3120 if (ttype == stype)
3121 break;
3122 if (!ttype || !stype)
3123 break;
3124 if (ttype == &void_ctype || stype == &void_ctype)
3125 break;
3126 if (tclass & TYPE_RESTRICT) {
3127 warning(expr->pos, "cast to %s", show_typename(ctype));
3128 break;
3129 }
3130 if (sclass & TYPE_RESTRICT) {
3131 warning(expr->pos, "cast from %s", show_typename(source->ctype));
3132 break;
3133 }
3134 }
3135 out:
3136 return ctype;
3137 }
3138
3139 /*
3140 * Evaluate a call expression with a symbol. This
3141 * should expand inline functions, and evaluate
3142 * builtins.
3143 */
3144 static int evaluate_symbol_call(struct expression *expr)
3145 {
3146 struct expression *fn = expr->fn;
3147 struct symbol *ctype = fn->ctype;
3148
3149 if (fn->type != EXPR_PREOP)
3150 return 0;
3151
3152 if (ctype->op && ctype->op->evaluate)
3153 return ctype->op->evaluate(expr);
3154
3155 return 0;
3156 }
3157
3158 static struct symbol *evaluate_call(struct expression *expr)
3159 {
3160 int args, fnargs;
3161 struct symbol *ctype, *sym;
3162 struct expression *fn = expr->fn;
3163 struct expression_list *arglist = expr->args;
3164
3165 if (!evaluate_expression(fn))
3166 return NULL;
3167 sym = ctype = fn->ctype;
3168 if (ctype->type == SYM_NODE)
3169 ctype = ctype->ctype.base_type;
3170 if (ctype->type == SYM_PTR)
3171 ctype = get_base_type(ctype);
3172
3173 if (ctype->type != SYM_FN) {
3174 struct expression *arg;
3175
3176 if (fn->ctype == &bad_ctype)
3177 return NULL;
3178
3179 expression_error(expr, "not a function %s",
3180 show_ident(sym->ident));
3181 /* do typechecking in arguments */
3182 FOR_EACH_PTR (arglist, arg) {
3183 evaluate_expression(arg);
3184 } END_FOR_EACH_PTR(arg);
3185 return NULL;
3186 }
3187
3188 examine_fn_arguments(ctype);
3189 if (sym->type == SYM_NODE && fn->type == EXPR_PREOP &&
3190 sym->op && sym->op->args) {
3191 if (!sym->op->args(expr))
3192 return NULL;
3193 } else {
3194 if (!evaluate_arguments(ctype->arguments, arglist))
3195 return NULL;
3196 args = expression_list_size(expr->args);
3197 fnargs = symbol_list_size(ctype->arguments);
3198 if (args < fnargs) {
3199 expression_error(expr,
3200 "not enough arguments for function %s",
3201 show_ident(sym->ident));
3202 return NULL;
3203 }
3204 if (args > fnargs && !ctype->variadic)
3205 expression_error(expr,
3206 "too many arguments for function %s",
3207 show_ident(sym->ident));
3208 }
3209 expr->ctype = ctype->ctype.base_type;
3210 if (sym->type == SYM_NODE) {
3211 if (evaluate_symbol_call(expr))
3212 return expr->ctype;
3213 }
3214 return expr->ctype;
3215 }
3216
3217 static struct symbol *evaluate_offsetof(struct expression *expr)
3218 {
3219 struct expression *e = expr->down;
3220 struct symbol *ctype = expr->in;
3221 int class;
3222
3223 if (expr->op == '.') {
3224 struct symbol *field;
3225 int offset = 0;
3226 if (!ctype) {
3227 expression_error(expr, "expected structure or union");
3228 return NULL;
3229 }
3230 examine_symbol_type(ctype);
3231 class = classify_type(ctype, &ctype);
3232 if (class != TYPE_COMPOUND) {
3233 expression_error(expr, "expected structure or union");
3234 return NULL;
3235 }
3236
3237 field = find_identifier(expr->ident, ctype->symbol_list, &offset);
3238 if (!field) {
3239 expression_error(expr, "unknown member");
3240 return NULL;
3241 }
3242 ctype = field;
3243 expr->type = EXPR_VALUE;
3244 expr->flags = CEF_SET_ICE;
3245 expr->value = offset;
3246 expr->taint = 0;
3247 expr->ctype = size_t_ctype;
3248 } else {
3249 if (!ctype) {
3250 expression_error(expr, "expected structure or union");
3251 return NULL;
3252 }
3253 examine_symbol_type(ctype);
3254 class = classify_type(ctype, &ctype);
3255 if (class != (TYPE_COMPOUND | TYPE_PTR)) {
3256 expression_error(expr, "expected array");
3257 return NULL;
3258 }
3259 ctype = ctype->ctype.base_type;
3260 if (!expr->index) {
3261 expr->type = EXPR_VALUE;
3262 expr->flags = CEF_SET_ICE;
3263 expr->value = 0;
3264 expr->taint = 0;
3265 expr->ctype = size_t_ctype;
3266 } else {
3267 struct expression *idx = expr->index, *m;
3268 struct symbol *i_type = evaluate_expression(idx);
3269 unsigned old_idx_flags;
3270 int i_class = classify_type(i_type, &i_type);
3271
3272 if (!is_int(i_class)) {
3273 expression_error(expr, "non-integer index");
3274 return NULL;
3275 }
3276 unrestrict(idx, i_class, &i_type);
3277 old_idx_flags = idx->flags;
3278 idx = cast_to(idx, size_t_ctype);
3279 idx->flags = old_idx_flags;
3280 m = alloc_const_expression(expr->pos,
3281 bits_to_bytes(ctype->bit_size));
3282 m->ctype = size_t_ctype;
3283 m->flags = CEF_SET_INT;
3284 expr->type = EXPR_BINOP;
3285 expr->left = idx;
3286 expr->right = m;
3287 expr->op = '*';
3288 expr->ctype = size_t_ctype;
3289 expr->flags = m->flags & idx->flags & ~CEF_CONST_MASK;
3290 }
3291 }
3292 if (e) {
3293 struct expression *copy = __alloc_expression(0);
3294 *copy = *expr;
3295 if (e->type == EXPR_OFFSETOF)
3296 e->in = ctype;
3297 if (!evaluate_expression(e))
3298 return NULL;
3299 expr->type = EXPR_BINOP;
3300 expr->flags = e->flags & copy->flags & ~CEF_CONST_MASK;
3301 expr->op = '+';
3302 expr->ctype = size_t_ctype;
3303 expr->left = copy;
3304 expr->right = e;
3305 }
3306 return size_t_ctype;
3307 }
3308
3309 static void check_label_declaration(struct position pos, struct symbol *label)
3310 {
3311 switch (label->namespace) {
3312 case NS_LABEL:
3313 if (label->stmt)
3314 break;
3315 sparse_error(pos, "label '%s' was not declared", show_ident(label->ident));
3316 /* fallthrough */
3317 case NS_NONE:
3318 current_fn->bogus_linear = 1;
3319 default:
3320 break;
3321 }
3322 }
3323
3324 static int type_selection(struct symbol *ctrl, struct symbol *type)
3325 {
3326 struct ctype c = { .base_type = ctrl };
3327 struct ctype t = { .base_type = type };
3328
3329 return !type_difference(&c, &t, 0, 0);
3330 }
3331
3332 static struct symbol *evaluate_generic_selection(struct expression *expr)
3333 {
3334 struct type_expression *map;
3335 struct expression *res;
3336 struct symbol source;
3337 struct symbol *ctrl;
3338
3339 if (!evaluate_expression(expr->control))
3340 return NULL;
3341 if (!(ctrl = degenerate(expr->control)))
3342 return NULL;
3343
3344 source = *ctrl;
3345 source.ctype.modifiers &= ~(MOD_QUALIFIER|MOD_ATOMIC);
3346 for (map = expr->map; map; map = map->next) {
3347 struct symbol *stype = map->type;
3348 struct symbol *base;
3349
3350 if (!evaluate_symbol(stype))
3351 continue;
3352
3353 base = stype->ctype.base_type;
3354 if (base->type == SYM_ARRAY && base->array_size) {
3355 get_expression_value_silent(base->array_size);
3356 if (base->array_size->type == EXPR_VALUE)
3357 continue;
3358 sparse_error(stype->pos, "variable length array type in generic selection");
3359 continue;
3360 }
3361 if (is_func_type(stype)) {
3362 sparse_error(stype->pos, "function type in generic selection");
3363 continue;
3364 }
3365 if (stype->bit_size <= 0 || is_void_type(stype)) {
3366 sparse_error(stype->pos, "incomplete type in generic selection");
3367 continue;
3368 }
3369 if (!type_selection(&source, stype))
3370 continue;
3371
3372 res = map->expr;
3373 goto found;
3374 }
3375 res = expr->def;
3376 if (!res) {
3377 sparse_error(expr->pos, "no generic selection for '%s'", show_typename(ctrl));
3378 return NULL;
3379 }
3380
3381 found:
3382 *expr = *res;
3383 return evaluate_expression(expr);
3384 }
3385
3386 struct symbol *evaluate_expression(struct expression *expr)
3387 {
3388 if (!expr)
3389 return NULL;
3390 if (expr->ctype)
3391 return expr->ctype;
3392
3393 switch (expr->type) {
3394 case EXPR_VALUE:
3395 case EXPR_FVALUE:
3396 expression_error(expr, "value expression without a type");
3397 return NULL;
3398 case EXPR_STRING:
3399 return evaluate_string(expr);
3400 case EXPR_SYMBOL:
3401 return evaluate_symbol_expression(expr);
3402 case EXPR_BINOP:
3403 evaluate_expression(expr->left);
3404 evaluate_expression(expr->right);
3405 if (!valid_subexpr_type(expr))
3406 return NULL;
3407 return evaluate_binop(expr);
3408 case EXPR_LOGICAL:
3409 return evaluate_logical(expr);
3410 case EXPR_COMMA:
3411 evaluate_expression(expr->left);
3412 if (!evaluate_expression(expr->right))
3413 return NULL;
3414 return evaluate_comma(expr);
3415 case EXPR_COMPARE:
3416 evaluate_expression(expr->left);
3417 evaluate_expression(expr->right);
3418 if (!valid_subexpr_type(expr))
3419 return NULL;
3420 return evaluate_compare(expr);
3421 case EXPR_ASSIGNMENT:
3422 evaluate_expression(expr->left);
3423 evaluate_expression(expr->right);
3424 if (!valid_subexpr_type(expr))
3425 return NULL;
3426 return evaluate_assignment(expr);
3427 case EXPR_PREOP:
3428 if (!evaluate_expression(expr->unop))
3429 return NULL;
3430 return evaluate_preop(expr);
3431 case EXPR_POSTOP:
3432 if (!evaluate_expression(expr->unop))
3433 return NULL;
3434 return evaluate_postop(expr);
3435 case EXPR_CAST:
3436 case EXPR_FORCE_CAST:
3437 case EXPR_IMPLIED_CAST:
3438 return evaluate_cast(expr);
3439 case EXPR_SIZEOF:
3440 return evaluate_sizeof(expr);
3441 case EXPR_PTRSIZEOF:
3442 return evaluate_ptrsizeof(expr);
3443 case EXPR_ALIGNOF:
3444 return evaluate_alignof(expr);
3445 case EXPR_DEREF:
3446 return evaluate_member_dereference(expr);
3447 case EXPR_CALL:
3448 return evaluate_call(expr);
3449 case EXPR_SELECT:
3450 case EXPR_CONDITIONAL:
3451 return evaluate_conditional_expression(expr);
3452 case EXPR_STATEMENT:
3453 expr->ctype = evaluate_statement(expr->statement);
3454 return expr->ctype;
3455
3456 case EXPR_LABEL:
3457 expr->ctype = &ptr_ctype;
3458 check_label_declaration(expr->pos, expr->label_symbol);
3459 return &ptr_ctype;
3460
3461 case EXPR_TYPE:
3462 /* Evaluate the type of the symbol .. */
3463 evaluate_symbol(expr->symbol);
3464 /* .. but the type of the _expression_ is a "type" */
3465 expr->ctype = &type_ctype;
3466 return &type_ctype;
3467
3468 case EXPR_OFFSETOF:
3469 return evaluate_offsetof(expr);
3470
3471 case EXPR_GENERIC:
3472 return evaluate_generic_selection(expr);
3473
3474 /* These can not exist as stand-alone expressions */
3475 case EXPR_INITIALIZER:
3476 case EXPR_IDENTIFIER:
3477 case EXPR_INDEX:
3478 case EXPR_POS:
3479 expression_error(expr, "internal front-end error: initializer in expression");
3480 return NULL;
3481 case EXPR_SLICE:
3482 expression_error(expr, "internal front-end error: SLICE re-evaluated");
3483 return NULL;
3484 }
3485 return NULL;
3486 }
3487
3488 void check_duplicates(struct symbol *sym)
3489 {
3490 int declared = 0;
3491 struct symbol *next = sym;
3492 int initialized = sym->initializer != NULL;
3493
3494 while ((next = next->same_symbol) != NULL) {
3495 const char *typediff;
3496 evaluate_symbol(next);
3497 if (initialized && next->initializer) {
3498 sparse_error(sym->pos, "symbol '%s' has multiple initializers (originally initialized at %s:%d)",
3499 show_ident(sym->ident),
3500 stream_name(next->pos.stream), next->pos.line);
3501 /* Only warn once */
3502 initialized = 0;
3503 }
3504 declared++;
3505 typediff = type_difference(&sym->ctype, &next->ctype, 0, 0);
3506 if (typediff) {
3507 sparse_error(sym->pos, "symbol '%s' redeclared with different type (%s):",
3508 show_ident(sym->ident), typediff);
3509 info(sym->pos, " %s", show_typename(sym));
3510 info(next->pos, "note: previously declared as:");
3511 info(next->pos, " %s", show_typename(next));
3512 return;
3513 }
3514 }
3515 if (!declared) {
3516 unsigned long mod = sym->ctype.modifiers;
3517 if (mod & (MOD_STATIC | MOD_REGISTER | MOD_EXT_VISIBLE))
3518 return;
3519 if (!(mod & MOD_TOPLEVEL))
3520 return;
3521 if (!Wdecl)
3522 return;
3523 if (sym->ident == &main_ident)
3524 return;
3525 warning(sym->pos, "symbol '%s' was not declared. Should it be static?", show_ident(sym->ident));
3526 }
3527 }
3528
3529 static struct symbol *evaluate_symbol(struct symbol *sym)
3530 {
3531 struct symbol *base_type;
3532
3533 if (!sym)
3534 return sym;
3535 if (sym->evaluated)
3536 return sym;
3537 sym->evaluated = 1;
3538
3539 sym = examine_symbol_type(sym);
3540 base_type = get_base_type(sym);
3541 if (!base_type)
3542 return NULL;
3543
3544 /* Evaluate the initializers */
3545 if (sym->initializer)
3546 evaluate_initializer(sym, &sym->initializer);
3547
3548 /* And finally, evaluate the body of the symbol too */
3549 if (base_type->type == SYM_FN) {
3550 struct symbol *curr = current_fn;
3551
3552 if (sym->definition && sym->definition != sym)
3553 return evaluate_symbol(sym->definition);
3554
3555 current_fn = sym;
3556
3557 examine_fn_arguments(base_type);
3558 if (!base_type->stmt && base_type->inline_stmt && sym->definition)
3559 uninline(sym);
3560 if (base_type->stmt)
3561 evaluate_statement(base_type->stmt);
3562
3563 current_fn = curr;
3564 }
3565
3566 return base_type;
3567 }
3568
3569 void evaluate_symbol_list(struct symbol_list *list)
3570 {
3571 struct symbol *sym;
3572
3573 FOR_EACH_PTR(list, sym) {
3574 has_error &= ~ERROR_CURR_PHASE;
3575 evaluate_symbol(sym);
3576 check_duplicates(sym);
3577 } END_FOR_EACH_PTR(sym);
3578 }
3579
3580 static struct symbol *evaluate_return_expression(struct statement *stmt)
3581 {
3582 struct expression *expr = stmt->expression;
3583 struct symbol *fntype, *rettype;
3584
3585 evaluate_expression(expr);
3586 fntype = current_fn->ctype.base_type;
3587 rettype = fntype->ctype.base_type;
3588 if (!rettype || rettype == &void_ctype) {
3589 if (expr && expr->ctype && !is_void_type(expr->ctype))
3590 expression_error(expr, "return expression in %s function", rettype?"void":"typeless");
3591 if (expr && Wreturn_void)
3592 warning(stmt->pos, "returning void-valued expression");
3593 return NULL;
3594 }
3595
3596 if (!expr) {
3597 sparse_error(stmt->pos, "return with no return value");
3598 return NULL;
3599 }
3600 if (!expr->ctype)
3601 return NULL;
3602 compatible_assignment_types(expr, rettype, &stmt->expression, "return expression");
3603 return NULL;
3604 }
3605
3606 static void evaluate_if_statement(struct statement *stmt)
3607 {
3608 if (!stmt->if_conditional)
3609 return;
3610
3611 evaluate_conditional(stmt->if_conditional, 0);
3612 evaluate_statement(stmt->if_true);
3613 evaluate_statement(stmt->if_false);
3614 }
3615
3616 static void evaluate_iterator(struct statement *stmt)
3617 {
3618 evaluate_symbol_list(stmt->iterator_syms);
3619 evaluate_conditional(stmt->iterator_pre_condition, 1);
3620 evaluate_conditional(stmt->iterator_post_condition,1);
3621 evaluate_statement(stmt->iterator_pre_statement);
3622 evaluate_statement(stmt->iterator_statement);
3623 evaluate_statement(stmt->iterator_post_statement);
3624 }
3625
3626
3627 static void parse_asm_constraint(struct asm_operand *op)
3628 {
3629 struct expression *constraint = op->constraint;
3630 const char *str = constraint->string->data;
3631 int c;
3632
3633 switch (str[0]) {
3634 case '\0':
3635 sparse_error(constraint->pos, "invalid ASM constraint (\"\")");
3636 break;
3637 case '+':
3638 op->is_modify = true;
3639 /* fall-through */
3640 case '=':
3641 op->is_assign = true;
3642 str++;
3643 break;
3644 }
3645
3646 while ((c = *str++)) {
3647 switch (c) {
3648 case '=':
3649 case '+':
3650 sparse_error(constraint->pos, "invalid ASM constraint '%c'", c);
3651 break;
3652
3653 case '&':
3654 op->is_earlyclobber = true;
3655 break;
3656 case '%':
3657 op->is_commutative = true;
3658 break;
3659 case 'r':
3660 op->is_register = true;
3661 break;
3662
3663 case 'm':
3664 case 'o':
3665 case 'V':
3666 case 'Q':
3667 op->is_memory = true;
3668 break;
3669
3670 case '<':
3671 case '>':
3672 // FIXME: ignored for now
3673 break;
3674
3675 case ',':
3676 // FIXME: multiple alternative constraints
3677 break;
3678
3679 case '0' ... '9':
3680 // FIXME: numeric matching constraint?
3681 break;
3682 case '[':
3683 // FIXME: symbolic matching constraint
3684 return;
3685
3686 default:
3687 if (arch_target->asm_constraint)
3688 str = arch_target->asm_constraint(op, c, str);
3689
3690 // FIXME: multi-letter constraints
3691 break;
3692 }
3693 }
3694
3695 // FIXME: how to deal with multi-constraint?
3696 if (op->is_register)
3697 op->is_memory = 0;
3698 }
3699
3700 static void verify_output_constraint(struct asm_operand *op)
3701 {
3702 struct expression *expr = op->constraint;
3703 const char *constraint = expr->string->data;
3704
3705 if (!op->is_assign)
3706 expression_error(expr, "output constraint is not an assignment constraint (\"%s\")", constraint);
3707 }
3708
3709 static void verify_input_constraint(struct asm_operand *op)
3710 {
3711 struct expression *expr = op->constraint;
3712 const char *constraint = expr->string->data;
3713
3714 if (op->is_assign)
3715 expression_error(expr, "input constraint with assignment (\"%s\")", constraint);
3716 }
3717
3718 static void evaluate_asm_memop(struct asm_operand *op)
3719 {
3720 if (op->is_memory) {
3721 struct expression *expr = op->expr;
3722 struct expression *addr;
3723
3724 // implicit addressof
3725 addr = alloc_expression(expr->pos, EXPR_PREOP);
3726 addr->op = '&';
3727 addr->unop = expr;
3728
3729 evaluate_addressof(addr);
3730 op->expr = addr;
3731 } else {
3732 evaluate_expression(op->expr);
3733 degenerate(op->expr);
3734 }
3735 }
3736
3737 static void evaluate_asm_statement(struct statement *stmt)
3738 {
3739 struct expression *expr;
3740 struct asm_operand *op;
3741 struct symbol *sym;
3742
3743 if (!stmt->asm_string)
3744 return;
3745
3746 FOR_EACH_PTR(stmt->asm_outputs, op) {
3747 /* Identifier */
3748
3749 /* Constraint */
3750 if (op->constraint) {
3751 parse_asm_constraint(op);
3752 verify_output_constraint(op);
3753 }
3754
3755 /* Expression */
3756 expr = op->expr;
3757 if (!evaluate_expression(expr))
3758 return;
3759 if (!lvalue_expression(expr))
3760 warning(expr->pos, "asm output is not an lvalue");
3761 evaluate_assign_to(expr, expr->ctype);
3762 evaluate_asm_memop(op);
3763 } END_FOR_EACH_PTR(op);
3764
3765 FOR_EACH_PTR(stmt->asm_inputs, op) {
3766 /* Identifier */
3767
3768 /* Constraint */
3769 if (op->constraint) {
3770 parse_asm_constraint(op);
3771 verify_input_constraint(op);
3772 }
3773
3774 /* Expression */
3775 if (!evaluate_expression(op->expr))
3776 return;
3777 evaluate_asm_memop(op);
3778 } END_FOR_EACH_PTR(op);
3779
3780 FOR_EACH_PTR(stmt->asm_clobbers, expr) {
3781 if (!expr) {
3782 sparse_error(stmt->pos, "bad asm clobbers");
3783 return;
3784 }
3785 if (expr->type == EXPR_STRING)
3786 continue;
3787 expression_error(expr, "asm clobber is not a string");
3788 } END_FOR_EACH_PTR(expr);
3789
3790 FOR_EACH_PTR(stmt->asm_labels, sym) {
3791 if (!sym || sym->type != SYM_LABEL) {
3792 sparse_error(stmt->pos, "bad asm label");
3793 return;
3794 }
3795 } END_FOR_EACH_PTR(sym);
3796 }
3797
3798 static void evaluate_case_statement(struct statement *stmt)
3799 {
3800 evaluate_expression(stmt->case_expression);
3801 evaluate_expression(stmt->case_to);
3802 evaluate_statement(stmt->case_statement);
3803 }
3804
3805 static void check_case_type(struct expression *switch_expr,
3806 struct expression *case_expr,
3807 struct expression **enumcase)
3808 {
3809 struct symbol *switch_type, *case_type;
3810 int sclass, cclass;
3811
3812 if (!case_expr)
3813 return;
3814
3815 switch_type = switch_expr->ctype;
3816 case_type = evaluate_expression(case_expr);
3817
3818 if (!switch_type || !case_type)
3819 goto Bad;
3820 if (enumcase) {
3821 if (*enumcase)
3822 warn_for_different_enum_types(case_expr->pos, case_type, (*enumcase)->ctype);
3823 else if (is_enum_type(case_type))
3824 *enumcase = case_expr;
3825 }
3826
3827 sclass = classify_type(switch_type, &switch_type);
3828 cclass = classify_type(case_type, &case_type);
3829
3830 /* both should be arithmetic */
3831 if (!(sclass & cclass & TYPE_NUM))
3832 goto Bad;
3833
3834 /* neither should be floating */
3835 if ((sclass | cclass) & TYPE_FLOAT)
3836 goto Bad;
3837
3838 /* if neither is restricted, we are OK */
3839 if (!((sclass | cclass) & TYPE_RESTRICT))
3840 return;
3841
3842 if (!restricted_binop_type(SPECIAL_EQUAL, case_expr, switch_expr,
3843 cclass, sclass, case_type, switch_type)) {
3844 unrestrict(case_expr, cclass, &case_type);
3845 unrestrict(switch_expr, sclass, &switch_type);
3846 }
3847 return;
3848
3849 Bad:
3850 expression_error(case_expr, "incompatible types for 'case' statement");
3851 }
3852
3853 static void evaluate_switch_statement(struct statement *stmt)
3854 {
3855 struct symbol *sym;
3856 struct expression *enumcase = NULL;
3857 struct expression **enumcase_holder = &enumcase;
3858 struct expression *sel = stmt->switch_expression;
3859
3860 evaluate_expression(sel);
3861 evaluate_statement(stmt->switch_statement);
3862 if (!sel)
3863 return;
3864 if (sel->ctype && is_enum_type(sel->ctype))
3865 enumcase_holder = NULL; /* Only check cases against switch */
3866
3867 FOR_EACH_PTR(stmt->switch_case->symbol_list, sym) {
3868 struct statement *case_stmt = sym->stmt;
3869 check_case_type(sel, case_stmt->case_expression, enumcase_holder);
3870 check_case_type(sel, case_stmt->case_to, enumcase_holder);
3871 } END_FOR_EACH_PTR(sym);
3872 }
3873
3874 static void evaluate_goto_statement(struct statement *stmt)
3875 {
3876 struct symbol *label = stmt->goto_label;
3877
3878 if (!label) {
3879 // no label associated, may be a computed goto
3880 evaluate_expression(stmt->goto_expression);
3881 return;
3882 }
3883
3884 check_label_declaration(stmt->pos, label);
3885 }
3886
3887 struct symbol *evaluate_statement(struct statement *stmt)
3888 {
3889 if (!stmt)
3890 return NULL;
3891
3892 switch (stmt->type) {
3893 case STMT_DECLARATION: {
3894 struct symbol *s;
3895 FOR_EACH_PTR(stmt->declaration, s) {
3896 evaluate_symbol(s);
3897 } END_FOR_EACH_PTR(s);
3898 return NULL;
3899 }
3900
3901 case STMT_RETURN:
3902 return evaluate_return_expression(stmt);
3903
3904 case STMT_EXPRESSION:
3905 if (!evaluate_expression(stmt->expression))
3906 return NULL;
3907 if (stmt->expression->ctype == &null_ctype)
3908 stmt->expression = cast_to(stmt->expression, &ptr_ctype);
3909 return unqualify_type(degenerate(stmt->expression));
3910
3911 case STMT_COMPOUND: {
3912 struct statement *s;
3913 struct symbol *type = NULL;
3914
3915 /* Evaluate the return symbol in the compound statement */
3916 evaluate_symbol(stmt->ret);
3917
3918 /*
3919 * Then, evaluate each statement, making the type of the
3920 * compound statement be the type of the last statement
3921 */
3922 type = evaluate_statement(stmt->args);
3923 FOR_EACH_PTR(stmt->stmts, s) {
3924 type = evaluate_statement(s);
3925 } END_FOR_EACH_PTR(s);
3926 if (!type)
3927 type = &void_ctype;
3928 return type;
3929 }
3930 case STMT_IF:
3931 evaluate_if_statement(stmt);
3932 return NULL;
3933 case STMT_ITERATOR:
3934 evaluate_iterator(stmt);
3935 return NULL;
3936 case STMT_SWITCH:
3937 evaluate_switch_statement(stmt);
3938 return NULL;
3939 case STMT_CASE:
3940 evaluate_case_statement(stmt);
3941 return NULL;
3942 case STMT_LABEL:
3943 return evaluate_statement(stmt->label_statement);
3944 case STMT_GOTO:
3945 evaluate_goto_statement(stmt);
3946 return NULL;
3947 case STMT_NONE:
3948 break;
3949 case STMT_ASM:
3950 evaluate_asm_statement(stmt);
3951 return NULL;
3952 case STMT_CONTEXT:
3953 evaluate_expression(stmt->expression);
3954 return NULL;
3955 case STMT_RANGE:
3956 evaluate_expression(stmt->range_expression);
3957 evaluate_expression(stmt->range_low);
3958 evaluate_expression(stmt->range_high);
3959 return NULL;
3960 }
3961 return NULL;
3962 }
Static analysis for C