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avl: introduce avl_clone()
[smatch.git] / evaluate.c
blob0cddbb7b0c3b0fc2845e3fd52418781d13b853a5
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 "lib.h"
38 #include "allocate.h"
39 #include "parse.h"
40 #include "token.h"
41 #include "symbol.h"
42 #include "target.h"
43 #include "expression.h"
44
45 struct symbol *current_fn;
46
47 static struct symbol *degenerate(struct expression *expr);
48 static struct symbol *evaluate_symbol(struct symbol *sym);
49
50 static struct symbol *evaluate_symbol_expression(struct expression *expr)
51 {
52 struct expression *addr;
53 struct symbol *sym = expr->symbol;
54 struct symbol *base_type;
55
56 if (!sym) {
57 expression_error(expr, "undefined identifier '%s'", show_ident(expr->symbol_name));
58 return NULL;
59 }
60
61 examine_symbol_type(sym);
62
63 base_type = get_base_type(sym);
64 if (!base_type) {
65 expression_error(expr, "identifier '%s' has no type", show_ident(expr->symbol_name));
66 return NULL;
67 }
68
69 addr = alloc_expression(expr->pos, EXPR_SYMBOL);
70 addr->symbol = sym;
71 addr->symbol_name = expr->symbol_name;
72 addr->ctype = &lazy_ptr_ctype; /* Lazy evaluation: we need to do a proper job if somebody does &sym */
73 expr->type = EXPR_PREOP;
74 expr->op = '*';
75 expr->unop = addr;
76
77 /* The type of a symbol is the symbol itself! */
78 expr->ctype = sym;
79 return sym;
80 }
81
82 static struct symbol *evaluate_string(struct expression *expr)
83 {
84 struct symbol *sym = alloc_symbol(expr->pos, SYM_NODE);
85 struct symbol *array = alloc_symbol(expr->pos, SYM_ARRAY);
86 struct expression *addr = alloc_expression(expr->pos, EXPR_SYMBOL);
87 struct expression *initstr = alloc_expression(expr->pos, EXPR_STRING);
88 unsigned int length = expr->string->length;
89
90 sym->array_size = alloc_const_expression(expr->pos, length);
91 sym->bit_size = bytes_to_bits(length);
92 sym->ctype.alignment = 1;
93 sym->string = 1;
94 sym->ctype.modifiers = MOD_STATIC;
95 sym->ctype.base_type = array;
96 sym->initializer = initstr;
97
98 initstr->ctype = sym;
99 initstr->string = expr->string;
100
101 array->array_size = sym->array_size;
102 array->bit_size = bytes_to_bits(length);
103 array->ctype.alignment = 1;
104 array->ctype.modifiers = MOD_STATIC;
105 array->ctype.base_type = &char_ctype;
106
107 addr->symbol = sym;
108 addr->ctype = &lazy_ptr_ctype;
109
110 expr->type = EXPR_PREOP;
111 expr->op = '*';
112 expr->unop = addr;
113 expr->ctype = sym;
114 return sym;
115 }
116
117 /* type has come from classify_type and is an integer type */
118 static inline struct symbol *integer_promotion(struct symbol *type)
119 {
120 struct symbol *orig_type = type;
121 unsigned long mod = type->ctype.modifiers;
122 int width = type->bit_size;
123
124 /*
125 * Bitfields always promote to the base type,
126 * even if the bitfield might be bigger than
127 * an "int".
128 */
129 if (type->type == SYM_BITFIELD) {
130 type = type->ctype.base_type;
131 orig_type = type;
132 }
133 mod = type->ctype.modifiers;
134 if (width < bits_in_int)
135 return &int_ctype;
136
137 /* If char/short has as many bits as int, it still gets "promoted" */
138 if (mod & (MOD_CHAR | MOD_SHORT)) {
139 if (mod & MOD_UNSIGNED)
140 return &uint_ctype;
141 return &int_ctype;
142 }
143 return orig_type;
144 }
145
146 /*
147 * integer part of usual arithmetic conversions:
148 * integer promotions are applied
149 * if left and right are identical, we are done
150 * if signedness is the same, convert one with lower rank
151 * unless unsigned argument has rank lower than signed one, convert the
152 * signed one.
153 * if signed argument is bigger than unsigned one, convert the unsigned.
154 * otherwise, convert signed.
155 *
156 * Leaving aside the integer promotions, that is equivalent to
157 * if identical, don't convert
158 * if left is bigger than right, convert right
159 * if right is bigger than left, convert right
160 * otherwise, if signedness is the same, convert one with lower rank
161 * otherwise convert the signed one.
162 */
163 static struct symbol *bigger_int_type(struct symbol *left, struct symbol *right)
164 {
165 unsigned long lmod, rmod;
166
167 left = integer_promotion(left);
168 right = integer_promotion(right);
169
170 if (left == right)
171 goto left;
172
173 if (left->bit_size > right->bit_size)
174 goto left;
175
176 if (right->bit_size > left->bit_size)
177 goto right;
178
179 lmod = left->ctype.modifiers;
180 rmod = right->ctype.modifiers;
181 if ((lmod ^ rmod) & MOD_UNSIGNED) {
182 if (lmod & MOD_UNSIGNED)
183 goto left;
184 } else if ((lmod & ~rmod) & (MOD_LONG_ALL))
185 goto left;
186 right:
187 left = right;
188 left:
189 return left;
190 }
191
192 static int same_cast_type(struct symbol *orig, struct symbol *new)
193 {
194 return orig->bit_size == new->bit_size &&
195 orig->bit_offset == new->bit_offset;
196 }
197
198 static struct symbol *base_type(struct symbol *node, unsigned long *modp, unsigned long *asp)
199 {
200 unsigned long mod, as;
201
202 mod = 0; as = 0;
203 while (node) {
204 mod |= node->ctype.modifiers;
205 as |= node->ctype.attribute->as;
206 if (node->type == SYM_NODE) {
207 node = node->ctype.base_type;
208 continue;
209 }
210 break;
211 }
212 *modp = mod & ~MOD_IGNORE;
213 *asp = as;
214 return node;
215 }
216
217 static int is_same_type(struct expression *expr, struct symbol *new)
218 {
219 struct symbol *old = expr->ctype;
220 unsigned long oldmod, newmod, oldas, newas;
221
222 old = base_type(old, &oldmod, &oldas);
223 new = base_type(new, &newmod, &newas);
224
225 /* Same base type, same address space? */
226 if (old == new && oldas == newas) {
227 unsigned long difmod;
228
229 /* Check the modifier bits. */
230 difmod = (oldmod ^ newmod) & ~MOD_NOCAST;
231
232 /* Exact same type? */
233 if (!difmod)
234 return 1;
235
236 /*
237 * Not the same type, but differs only in "const".
238 * Don't warn about MOD_NOCAST.
239 */
240 if (difmod == MOD_CONST)
241 return 0;
242 }
243 if ((oldmod | newmod) & MOD_NOCAST) {
244 const char *tofrom = "to/from";
245 if (!(newmod & MOD_NOCAST))
246 tofrom = "from";
247 if (!(oldmod & MOD_NOCAST))
248 tofrom = "to";
249 warning(expr->pos, "implicit cast %s nocast type", tofrom);
250 }
251 return 0;
252 }
253
254 static void
255 warn_for_different_enum_types (struct position pos,
256 struct symbol *typea,
257 struct symbol *typeb)
258 {
259 if (!Wenum_mismatch)
260 return;
261 if (typea->type == SYM_NODE)
262 typea = typea->ctype.base_type;
263 if (typeb->type == SYM_NODE)
264 typeb = typeb->ctype.base_type;
265
266 if (typea == typeb)
267 return;
268
269 if (typea->type == SYM_ENUM && typeb->type == SYM_ENUM) {
270 warning(pos, "mixing different enum types");
271 info(pos, " %s versus", show_typename(typea));
272 info(pos, " %s", show_typename(typeb));
273 }
274 }
275
276 /*
277 * This gets called for implicit casts in assignments and
278 * integer promotion. We often want to try to move the
279 * cast down, because the ops involved may have been
280 * implicitly cast up, and we can get rid of the casts
281 * early.
282 */
283 static struct expression * cast_to(struct expression *old, struct symbol *type)
284 {
285 struct expression *expr;
286
287 warn_for_different_enum_types (old->pos, old->ctype, type);
288
289 if (old->ctype != &null_ctype && is_same_type(old, type))
290 return old;
291
292 /*
293 * See if we can simplify the op. Move the cast down.
294 */
295 switch (old->type) {
296 case EXPR_PREOP:
297 if (old->ctype->bit_size < type->bit_size)
298 break;
299 if (old->op == '~') {
300 old->ctype = type;
301 old->unop = cast_to(old->unop, type);
302 return old;
303 }
304 break;
305
306 case EXPR_IMPLIED_CAST:
307 warn_for_different_enum_types(old->pos, old->ctype, type);
308
309 if (old->ctype->bit_size >= type->bit_size) {
310 struct expression *orig = old->cast_expression;
311 if (same_cast_type(orig->ctype, type))
312 return orig;
313 if (old->ctype->bit_offset == type->bit_offset) {
314 old->ctype = type;
315 old->cast_type = type;
316 return old;
317 }
318 }
319 break;
320
321 default:
322 /* nothing */;
323 }
324
325 expr = alloc_expression(old->pos, EXPR_IMPLIED_CAST);
326 expr->flags = old->flags;
327 expr->ctype = type;
328 expr->cast_type = type;
329 expr->cast_expression = old;
330 return expr;
331 }
332
333 enum {
334 TYPE_NUM = 1,
335 TYPE_BITFIELD = 2,
336 TYPE_RESTRICT = 4,
337 TYPE_FLOAT = 8,
338 TYPE_PTR = 16,
339 TYPE_COMPOUND = 32,
340 TYPE_FOULED = 64,
341 TYPE_FN = 128,
342 };
343
344 static inline int classify_type(struct symbol *type, struct symbol **base)
345 {
346 static int type_class[SYM_BAD + 1] = {
347 [SYM_PTR] = TYPE_PTR,
348 [SYM_FN] = TYPE_PTR | TYPE_FN,
349 [SYM_ARRAY] = TYPE_PTR | TYPE_COMPOUND,
350 [SYM_STRUCT] = TYPE_COMPOUND,
351 [SYM_UNION] = TYPE_COMPOUND,
352 [SYM_BITFIELD] = TYPE_NUM | TYPE_BITFIELD,
353 [SYM_RESTRICT] = TYPE_NUM | TYPE_RESTRICT,
354 [SYM_FOULED] = TYPE_NUM | TYPE_RESTRICT | TYPE_FOULED,
355 };
356 if (type->type == SYM_NODE)
357 type = type->ctype.base_type;
358 if (type->type == SYM_TYPEOF) {
359 type = evaluate_expression(type->initializer);
360 if (!type)
361 type = &bad_ctype;
362 else if (type->type == SYM_NODE)
363 type = type->ctype.base_type;
364 }
365 if (type->type == SYM_ENUM)
366 type = type->ctype.base_type;
367 *base = type;
368 if (type->type == SYM_BASETYPE) {
369 if (type->ctype.base_type == &int_type)
370 return TYPE_NUM;
371 if (type->ctype.base_type == &fp_type)
372 return TYPE_NUM | TYPE_FLOAT;
373 }
374 return type_class[type->type];
375 }
376
377 #define is_int(class) ((class & (TYPE_NUM | TYPE_FLOAT)) == TYPE_NUM)
378
379 static inline int is_string_type(struct symbol *type)
380 {
381 if (type->type == SYM_NODE)
382 type = type->ctype.base_type;
383 return type->type == SYM_ARRAY && is_byte_type(type->ctype.base_type);
384 }
385
386 static struct symbol *bad_expr_type(struct expression *expr)
387 {
388 sparse_error(expr->pos, "incompatible types for operation (%s)", show_special(expr->op));
389 switch (expr->type) {
390 case EXPR_BINOP:
391 case EXPR_COMPARE:
392 info(expr->pos, " left side has type %s", show_typename(expr->left->ctype));
393 info(expr->pos, " right side has type %s", show_typename(expr->right->ctype));
394 break;
395 case EXPR_PREOP:
396 case EXPR_POSTOP:
397 info(expr->pos, " argument has type %s", show_typename(expr->unop->ctype));
398 break;
399 default:
400 break;
401 }
402
403 expr->flags = 0;
404 return expr->ctype = &bad_ctype;
405 }
406
407 static int restricted_value(struct expression *v, struct symbol *type)
408 {
409 if (v->type != EXPR_VALUE)
410 return 1;
411 if (v->value != 0)
412 return 1;
413 return 0;
414 }
415
416 static int restricted_binop(int op, struct symbol *type)
417 {
418 switch (op) {
419 case '&':
420 case '=':
421 case SPECIAL_AND_ASSIGN:
422 case SPECIAL_OR_ASSIGN:
423 case SPECIAL_XOR_ASSIGN:
424 return 1; /* unfoul */
425 case '|':
426 case '^':
427 case '?':
428 return 2; /* keep fouled */
429 case SPECIAL_EQUAL:
430 case SPECIAL_NOTEQUAL:
431 return 3; /* warn if fouled */
432 default:
433 return 0; /* warn */
434 }
435 }
436
437 static int restricted_unop(int op, struct symbol **type)
438 {
439 if (op == '~') {
440 if ((*type)->bit_size < bits_in_int)
441 *type = befoul(*type);
442 return 0;
443 } if (op == '+')
444 return 0;
445 return 1;
446 }
447
448 /* type should be SYM_FOULED */
449 static inline struct symbol *unfoul(struct symbol *type)
450 {
451 return type->ctype.base_type;
452 }
453
454 static struct symbol *restricted_binop_type(int op,
455 struct expression *left,
456 struct expression *right,
457 int lclass, int rclass,
458 struct symbol *ltype,
459 struct symbol *rtype)
460 {
461 struct symbol *ctype = NULL;
462 if (lclass & TYPE_RESTRICT) {
463 if (rclass & TYPE_RESTRICT) {
464 if (ltype == rtype) {
465 ctype = ltype;
466 } else if (lclass & TYPE_FOULED) {
467 if (unfoul(ltype) == rtype)
468 ctype = ltype;
469 } else if (rclass & TYPE_FOULED) {
470 if (unfoul(rtype) == ltype)
471 ctype = rtype;
472 }
473 } else {
474 if (!restricted_value(right, ltype))
475 ctype = ltype;
476 }
477 } else if (!restricted_value(left, rtype))
478 ctype = rtype;
479
480 if (ctype) {
481 switch (restricted_binop(op, ctype)) {
482 case 1:
483 if ((lclass ^ rclass) & TYPE_FOULED)
484 ctype = unfoul(ctype);
485 break;
486 case 3:
487 if (!(lclass & rclass & TYPE_FOULED))
488 break;
489 case 0:
490 ctype = NULL;
491 default:
492 break;
493 }
494 }
495
496 return ctype;
497 }
498
499 static inline void unrestrict(struct expression *expr,
500 int class, struct symbol **ctype)
501 {
502 if (class & TYPE_RESTRICT) {
503 if (class & TYPE_FOULED)
504 *ctype = unfoul(*ctype);
505 warning(expr->pos, "%s degrades to integer",
506 show_typename(*ctype));
507 *ctype = (*ctype)->ctype.base_type; /* get to arithmetic type */
508 }
509 }
510
511 static struct symbol *usual_conversions(int op,
512 struct expression *left,
513 struct expression *right,
514 int lclass, int rclass,
515 struct symbol *ltype,
516 struct symbol *rtype)
517 {
518 struct symbol *ctype;
519
520 warn_for_different_enum_types(right->pos, left->ctype, right->ctype);
521
522 if ((lclass | rclass) & TYPE_RESTRICT)
523 goto Restr;
524
525 Normal:
526 if (!(lclass & TYPE_FLOAT)) {
527 if (!(rclass & TYPE_FLOAT))
528 return bigger_int_type(ltype, rtype);
529 else
530 return rtype;
531 } else if (rclass & TYPE_FLOAT) {
532 unsigned long lmod = ltype->ctype.modifiers;
533 unsigned long rmod = rtype->ctype.modifiers;
534 if (rmod & ~lmod & (MOD_LONG_ALL))
535 return rtype;
536 else
537 return ltype;
538 } else
539 return ltype;
540
541 Restr:
542 ctype = restricted_binop_type(op, left, right,
543 lclass, rclass, ltype, rtype);
544 if (ctype)
545 return ctype;
546
547 unrestrict(left, lclass, &ltype);
548 unrestrict(right, rclass, &rtype);
549
550 goto Normal;
551 }
552
553 static inline int lvalue_expression(struct expression *expr)
554 {
555 return expr->type == EXPR_PREOP && expr->op == '*';
556 }
557
558 static struct symbol *evaluate_ptr_add(struct expression *expr, struct symbol *itype)
559 {
560 struct expression *index = expr->right;
561 struct symbol *ctype, *base;
562 int multiply;
563
564 classify_type(degenerate(expr->left), &ctype);
565 base = examine_pointer_target(ctype);
566
567 if (!base) {
568 expression_error(expr, "missing type information");
569 return NULL;
570 }
571 if (is_function(base)) {
572 expression_error(expr, "arithmetics on pointers to functions");
573 return NULL;
574 }
575
576 /* Get the size of whatever the pointer points to */
577 multiply = is_void_type(base) ? 1 : bits_to_bytes(base->bit_size);
578
579 if (ctype == &null_ctype)
580 ctype = &ptr_ctype;
581 expr->ctype = ctype;
582
583 if (multiply == 1 && itype->bit_size >= bits_in_pointer)
584 return ctype;
585
586 if (index->type == EXPR_VALUE) {
587 struct expression *val = alloc_expression(expr->pos, EXPR_VALUE);
588 unsigned long long v = index->value, mask;
589 mask = 1ULL << (itype->bit_size - 1);
590 if (v & mask)
591 v |= -mask;
592 else
593 v &= mask - 1;
594 v *= multiply;
595 mask = 1ULL << (bits_in_pointer - 1);
596 v &= mask | (mask - 1);
597 val->value = v;
598 val->ctype = ssize_t_ctype;
599 expr->right = val;
600 return ctype;
601 }
602
603 if (itype->bit_size < bits_in_pointer)
604 index = cast_to(index, ssize_t_ctype);
605
606 if (multiply > 1) {
607 struct expression *val = alloc_expression(expr->pos, EXPR_VALUE);
608 struct expression *mul = alloc_expression(expr->pos, EXPR_BINOP);
609
610 val->ctype = ssize_t_ctype;
611 val->value = multiply;
612
613 mul->op = '*';
614 mul->ctype = ssize_t_ctype;
615 mul->left = index;
616 mul->right = val;
617 index = mul;
618 }
619
620 expr->right = index;
621 return ctype;
622 }
623
624 static void examine_fn_arguments(struct symbol *fn);
625
626 #define MOD_IGN (MOD_VOLATILE | MOD_CONST)
627
628 const char *type_difference(struct ctype *c1, struct ctype *c2,
629 unsigned long mod1, unsigned long mod2)
630 {
631 unsigned long as1 = c1->attribute->as, as2 = c2->attribute->as;
632 struct symbol *t1 = c1->base_type;
633 struct symbol *t2 = c2->base_type;
634 int move1 = 1, move2 = 1;
635 mod1 |= c1->modifiers;
636 mod2 |= c2->modifiers;
637
638 for (;;) {
639 unsigned long diff;
640 int type;
641 struct symbol *base1 = t1->ctype.base_type;
642 struct symbol *base2 = t2->ctype.base_type;
643
644 /*
645 * FIXME! Collect alignment and context too here!
646 */
647 if (move1) {
648 if (t1 && t1->type != SYM_PTR) {
649 mod1 |= t1->ctype.modifiers;
650 as1 |= t1->ctype.attribute->as;
651 }
652 move1 = 0;
653 }
654
655 if (move2) {
656 if (t2 && t2->type != SYM_PTR) {
657 mod2 |= t2->ctype.modifiers;
658 as2 |= t2->ctype.attribute->as;
659 }
660 move2 = 0;
661 }
662
663 if (t1 == t2)
664 break;
665 if (!t1 || !t2)
666 return "different types";
667
668 if (t1->type == SYM_NODE || t1->type == SYM_ENUM) {
669 t1 = base1;
670 move1 = 1;
671 if (!t1)
672 return "bad types";
673 continue;
674 }
675
676 if (t2->type == SYM_NODE || t2->type == SYM_ENUM) {
677 t2 = base2;
678 move2 = 1;
679 if (!t2)
680 return "bad types";
681 continue;
682 }
683
684 move1 = move2 = 1;
685 type = t1->type;
686 if (type != t2->type)
687 return "different base types";
688
689 switch (type) {
690 default:
691 sparse_error(t1->pos,
692 "internal error: bad type in derived(%d)",
693 type);
694 return "bad types";
695 case SYM_RESTRICT:
696 return "different base types";
697 case SYM_UNION:
698 case SYM_STRUCT:
699 /* allow definition of incomplete structs and unions */
700 if (t1->ident == t2->ident)
701 return NULL;
702 return "different base types";
703 case SYM_ARRAY:
704 /* XXX: we ought to compare sizes */
705 break;
706 case SYM_PTR:
707 if (as1 != as2)
708 return "different address spaces";
709 /* MOD_SPECIFIER is due to idiocy in parse.c */
710 if ((mod1 ^ mod2) & ~MOD_IGNORE & ~MOD_SPECIFIER)
711 return "different modifiers";
712 /* we could be lazier here */
713 base1 = examine_pointer_target(t1);
714 base2 = examine_pointer_target(t2);
715 mod1 = t1->ctype.modifiers;
716 as1 = t1->ctype.attribute->as;
717 mod2 = t2->ctype.modifiers;
718 as2 = t2->ctype.attribute->as;
719 break;
720 case SYM_FN: {
721 struct symbol *arg1, *arg2;
722 int i;
723
724 if (as1 != as2)
725 return "different address spaces";
726 if ((mod1 ^ mod2) & ~MOD_IGNORE & ~MOD_SIGNEDNESS)
727 return "different modifiers";
728 mod1 = t1->ctype.modifiers;
729 as1 = t1->ctype.attribute->as;
730 mod2 = t2->ctype.modifiers;
731 as2 = t2->ctype.attribute->as;
732
733 if (base1->variadic != base2->variadic)
734 return "incompatible variadic arguments";
735 examine_fn_arguments(t1);
736 examine_fn_arguments(t2);
737 PREPARE_PTR_LIST(t1->arguments, arg1);
738 PREPARE_PTR_LIST(t2->arguments, arg2);
739 i = 1;
740 for (;;) {
741 const char *diffstr;
742 if (!arg1 && !arg2)
743 break;
744 if (!arg1 || !arg2)
745 return "different argument counts";
746 diffstr = type_difference(&arg1->ctype,
747 &arg2->ctype,
748 MOD_IGN, MOD_IGN);
749 if (diffstr) {
750 static char argdiff[80];
751 sprintf(argdiff, "incompatible argument %d (%s)", i, diffstr);
752 return argdiff;
753 }
754 NEXT_PTR_LIST(arg1);
755 NEXT_PTR_LIST(arg2);
756 i++;
757 }
758 FINISH_PTR_LIST(arg2);
759 FINISH_PTR_LIST(arg1);
760 break;
761 }
762 case SYM_BASETYPE:
763 if (as1 != as2)
764 return "different address spaces";
765 if (base1 != base2)
766 return "different base types";
767 diff = (mod1 ^ mod2) & ~MOD_IGNORE;
768 if (!diff)
769 return NULL;
770 if (diff & MOD_SIZE)
771 return "different type sizes";
772 else if (diff & ~MOD_SIGNEDNESS)
773 return "different modifiers";
774 else
775 return "different signedness";
776 }
777 t1 = base1;
778 t2 = base2;
779 }
780 if (as1 != as2)
781 return "different address spaces";
782 if ((mod1 ^ mod2) & ~MOD_IGNORE & ~MOD_SIGNEDNESS)
783 return "different modifiers";
784 return NULL;
785 }
786
787 static void bad_null(struct expression *expr)
788 {
789 if (Wnon_pointer_null)
790 warning(expr->pos, "Using plain integer as NULL pointer");
791 }
792
793 static unsigned long target_qualifiers(struct symbol *type)
794 {
795 unsigned long mod = type->ctype.modifiers & MOD_IGN;
796 if (type->ctype.base_type && type->ctype.base_type->type == SYM_ARRAY)
797 mod = 0;
798 return mod;
799 }
800
801 static struct symbol *evaluate_ptr_sub(struct expression *expr)
802 {
803 const char *typediff;
804 struct symbol *ltype, *rtype;
805 struct expression *l = expr->left;
806 struct expression *r = expr->right;
807 struct symbol *lbase;
808
809 classify_type(degenerate(l), &ltype);
810 classify_type(degenerate(r), &rtype);
811
812 lbase = examine_pointer_target(ltype);
813 examine_pointer_target(rtype);
814 typediff = type_difference(&ltype->ctype, &rtype->ctype,
815 target_qualifiers(rtype),
816 target_qualifiers(ltype));
817 if (typediff)
818 expression_error(expr, "subtraction of different types can't work (%s)", typediff);
819
820 if (is_function(lbase)) {
821 expression_error(expr, "subtraction of functions? Share your drugs");
822 return NULL;
823 }
824
825 expr->ctype = ssize_t_ctype;
826 if (lbase->bit_size > bits_in_char) {
827 struct expression *sub = alloc_expression(expr->pos, EXPR_BINOP);
828 struct expression *div = expr;
829 struct expression *val = alloc_expression(expr->pos, EXPR_VALUE);
830 unsigned long value = bits_to_bytes(lbase->bit_size);
831
832 val->ctype = size_t_ctype;
833 val->value = value;
834
835 if (value & (value-1)) {
836 if (Wptr_subtraction_blows)
837 warning(expr->pos, "potentially expensive pointer subtraction");
838 }
839
840 sub->op = '-';
841 sub->ctype = ssize_t_ctype;
842 sub->left = l;
843 sub->right = r;
844
845 div->op = '/';
846 div->left = sub;
847 div->right = val;
848 }
849
850 return ssize_t_ctype;
851 }
852
853 #define is_safe_type(type) ((type)->ctype.modifiers & MOD_SAFE)
854
855 static struct symbol *evaluate_conditional(struct expression *expr, int iterator)
856 {
857 struct symbol *ctype;
858
859 if (!expr)
860 return NULL;
861
862 if (!iterator && expr->type == EXPR_ASSIGNMENT && expr->op == '=')
863 warning(expr->pos, "assignment expression in conditional");
864
865 ctype = evaluate_expression(expr);
866 if (ctype) {
867 if (is_safe_type(ctype))
868 warning(expr->pos, "testing a 'safe expression'");
869 }
870
871 return ctype;
872 }
873
874 static struct symbol *evaluate_logical(struct expression *expr)
875 {
876 if (!evaluate_conditional(expr->left, 0))
877 return NULL;
878 if (!evaluate_conditional(expr->right, 0))
879 return NULL;
880
881 /* the result is int [6.5.13(3), 6.5.14(3)] */
882 expr->ctype = &int_ctype;
883 if (expr->flags) {
884 if (!(expr->left->flags & expr->right->flags & Int_const_expr))
885 expr->flags = 0;
886 }
887 return &int_ctype;
888 }
889
890 static struct symbol *evaluate_binop(struct expression *expr)
891 {
892 struct symbol *ltype, *rtype, *ctype;
893 int lclass = classify_type(expr->left->ctype, &ltype);
894 int rclass = classify_type(expr->right->ctype, &rtype);
895 int op = expr->op;
896
897 if (expr->flags) {
898 if (!(expr->left->flags & expr->right->flags & Int_const_expr))
899 expr->flags = 0;
900 }
901
902 /* number op number */
903 if (lclass & rclass & TYPE_NUM) {
904 if ((lclass | rclass) & TYPE_FLOAT) {
905 switch (op) {
906 case '+': case '-': case '*': case '/':
907 break;
908 default:
909 return bad_expr_type(expr);
910 }
911 }
912
913 if (op == SPECIAL_LEFTSHIFT || op == SPECIAL_RIGHTSHIFT) {
914 // shifts do integer promotions, but that's it.
915 unrestrict(expr->left, lclass, &ltype);
916 unrestrict(expr->right, rclass, &rtype);
917 ctype = ltype = integer_promotion(ltype);
918 rtype = integer_promotion(rtype);
919 } else {
920 // The rest do usual conversions
921 const unsigned left_not = expr->left->type == EXPR_PREOP
922 && expr->left->op == '!';
923 const unsigned right_not = expr->right->type == EXPR_PREOP
924 && expr->right->op == '!';
925 if ((op == '&' || op == '|') && (left_not || right_not))
926 warning(expr->pos, "dubious: %sx %c %sy",
927 left_not ? "!" : "",
928 op,
929 right_not ? "!" : "");
930
931 ltype = usual_conversions(op, expr->left, expr->right,
932 lclass, rclass, ltype, rtype);
933 ctype = rtype = ltype;
934 }
935
936 expr->left = cast_to(expr->left, ltype);
937 expr->right = cast_to(expr->right, rtype);
938 expr->ctype = ctype;
939 return ctype;
940 }
941
942 /* pointer (+|-) integer */
943 if (lclass & TYPE_PTR && is_int(rclass) && (op == '+' || op == '-')) {
944 unrestrict(expr->right, rclass, &rtype);
945 return evaluate_ptr_add(expr, rtype);
946 }
947
948 /* integer + pointer */
949 if (rclass & TYPE_PTR && is_int(lclass) && op == '+') {
950 struct expression *index = expr->left;
951 unrestrict(index, lclass, &ltype);
952 expr->left = expr->right;
953 expr->right = index;
954 return evaluate_ptr_add(expr, ltype);
955 }
956
957 /* pointer - pointer */
958 if (lclass & rclass & TYPE_PTR && expr->op == '-')
959 return evaluate_ptr_sub(expr);
960
961 return bad_expr_type(expr);
962 }
963
964 static struct symbol *evaluate_comma(struct expression *expr)
965 {
966 expr->ctype = degenerate(expr->right);
967 if (expr->ctype == &null_ctype)
968 expr->ctype = &ptr_ctype;
969 expr->flags &= expr->left->flags & expr->right->flags;
970 return expr->ctype;
971 }
972
973 static int modify_for_unsigned(int op)
974 {
975 if (op == '<')
976 op = SPECIAL_UNSIGNED_LT;
977 else if (op == '>')
978 op = SPECIAL_UNSIGNED_GT;
979 else if (op == SPECIAL_LTE)
980 op = SPECIAL_UNSIGNED_LTE;
981 else if (op == SPECIAL_GTE)
982 op = SPECIAL_UNSIGNED_GTE;
983 return op;
984 }
985
986 static inline int is_null_pointer_constant(struct expression *e)
987 {
988 if (e->ctype == &null_ctype)
989 return 1;
990 if (!(e->flags & Int_const_expr))
991 return 0;
992 return is_zero_constant(e) ? 2 : 0;
993 }
994
995 static struct symbol *evaluate_compare(struct expression *expr)
996 {
997 struct expression *left = expr->left, *right = expr->right;
998 struct symbol *ltype, *rtype, *lbase, *rbase;
999 int lclass = classify_type(degenerate(left), &ltype);
1000 int rclass = classify_type(degenerate(right), &rtype);
1001 struct symbol *ctype;
1002 const char *typediff;
1003
1004 if (expr->flags) {
1005 if (!(expr->left->flags & expr->right->flags & Int_const_expr))
1006 expr->flags = 0;
1007 }
1008
1009 /* Type types? */
1010 if (is_type_type(ltype) && is_type_type(rtype))
1011 goto OK;
1012
1013 if (is_safe_type(left->ctype) || is_safe_type(right->ctype))
1014 warning(expr->pos, "testing a 'safe expression'");
1015
1016 /* number on number */
1017 if (lclass & rclass & TYPE_NUM) {
1018 ctype = usual_conversions(expr->op, expr->left, expr->right,
1019 lclass, rclass, ltype, rtype);
1020 expr->left = cast_to(expr->left, ctype);
1021 expr->right = cast_to(expr->right, ctype);
1022 if (ctype->ctype.modifiers & MOD_UNSIGNED)
1023 expr->op = modify_for_unsigned(expr->op);
1024 goto OK;
1025 }
1026
1027 /* at least one must be a pointer */
1028 if (!((lclass | rclass) & TYPE_PTR))
1029 return bad_expr_type(expr);
1030
1031 /* equality comparisons can be with null pointer constants */
1032 if (expr->op == SPECIAL_EQUAL || expr->op == SPECIAL_NOTEQUAL) {
1033 int is_null1 = is_null_pointer_constant(left);
1034 int is_null2 = is_null_pointer_constant(right);
1035 if (is_null1 == 2)
1036 bad_null(left);
1037 if (is_null2 == 2)
1038 bad_null(right);
1039 if (is_null1 && is_null2) {
1040 int positive = expr->op == SPECIAL_EQUAL;
1041 expr->type = EXPR_VALUE;
1042 expr->value = positive;
1043 goto OK;
1044 }
1045 if (is_null1 && (rclass & TYPE_PTR)) {
1046 left = cast_to(left, rtype);
1047 goto OK;
1048 }
1049 if (is_null2 && (lclass & TYPE_PTR)) {
1050 right = cast_to(right, ltype);
1051 goto OK;
1052 }
1053 }
1054 /* both should be pointers */
1055 if (!(lclass & rclass & TYPE_PTR))
1056 return bad_expr_type(expr);
1057 expr->op = modify_for_unsigned(expr->op);
1058
1059 lbase = examine_pointer_target(ltype);
1060 rbase = examine_pointer_target(rtype);
1061
1062 /* they also have special treatment for pointers to void */
1063 if (expr->op == SPECIAL_EQUAL || expr->op == SPECIAL_NOTEQUAL) {
1064 if (ltype->ctype.attribute->as == rtype->ctype.attribute->as) {
1065 if (lbase == &void_ctype) {
1066 right = cast_to(right, ltype);
1067 goto OK;
1068 }
1069 if (rbase == &void_ctype) {
1070 left = cast_to(left, rtype);
1071 goto OK;
1072 }
1073 }
1074 }
1075
1076 typediff = type_difference(&ltype->ctype, &rtype->ctype,
1077 target_qualifiers(rtype),
1078 target_qualifiers(ltype));
1079 if (!typediff)
1080 goto OK;
1081
1082 expression_error(expr, "incompatible types in comparison expression (%s)", typediff);
1083 return NULL;
1084
1085 OK:
1086 /* the result is int [6.5.8(6), 6.5.9(3)]*/
1087 expr->ctype = &int_ctype;
1088 return &int_ctype;
1089 }
1090
1091 /*
1092 * NOTE! The degenerate case of "x ? : y", where we don't
1093 * have a true case, this will possibly promote "x" to the
1094 * same type as "y", and thus _change_ the conditional
1095 * test in the expression. But since promotion is "safe"
1096 * for testing, that's OK.
1097 */
1098 static struct symbol *evaluate_conditional_expression(struct expression *expr)
1099 {
1100 struct expression **true;
1101 struct symbol *ctype, *ltype, *rtype, *lbase, *rbase;
1102 int lclass, rclass;
1103 const char * typediff;
1104 int qual;
1105
1106 if (!evaluate_conditional(expr->conditional, 0))
1107 return NULL;
1108 if (!evaluate_expression(expr->cond_false))
1109 return NULL;
1110
1111 ctype = degenerate(expr->conditional);
1112 rtype = degenerate(expr->cond_false);
1113
1114 true = &expr->conditional;
1115 ltype = ctype;
1116 if (expr->cond_true) {
1117 if (!evaluate_expression(expr->cond_true))
1118 return NULL;
1119 ltype = degenerate(expr->cond_true);
1120 true = &expr->cond_true;
1121 }
1122
1123 if (expr->flags) {
1124 int flags = expr->conditional->flags & Int_const_expr;
1125 flags &= (*true)->flags & expr->cond_false->flags;
1126 if (!flags)
1127 expr->flags = 0;
1128 }
1129
1130 lclass = classify_type(ltype, &ltype);
1131 rclass = classify_type(rtype, &rtype);
1132 if (lclass & rclass & TYPE_NUM) {
1133 ctype = usual_conversions('?', *true, expr->cond_false,
1134 lclass, rclass, ltype, rtype);
1135 *true = cast_to(*true, ctype);
1136 expr->cond_false = cast_to(expr->cond_false, ctype);
1137 goto out;
1138 }
1139
1140 if ((lclass | rclass) & TYPE_PTR) {
1141 int is_null1 = is_null_pointer_constant(*true);
1142 int is_null2 = is_null_pointer_constant(expr->cond_false);
1143
1144 if (is_null1 && is_null2) {
1145 *true = cast_to(*true, &ptr_ctype);
1146 expr->cond_false = cast_to(expr->cond_false, &ptr_ctype);
1147 ctype = &ptr_ctype;
1148 goto out;
1149 }
1150 if (is_null1 && (rclass & TYPE_PTR)) {
1151 if (is_null1 == 2)
1152 bad_null(*true);
1153 *true = cast_to(*true, rtype);
1154 ctype = rtype;
1155 goto out;
1156 }
1157 if (is_null2 && (lclass & TYPE_PTR)) {
1158 if (is_null2 == 2)
1159 bad_null(expr->cond_false);
1160 expr->cond_false = cast_to(expr->cond_false, ltype);
1161 ctype = ltype;
1162 goto out;
1163 }
1164 if (!(lclass & rclass & TYPE_PTR)) {
1165 typediff = "different types";
1166 goto Err;
1167 }
1168 /* OK, it's pointer on pointer */
1169 if (ltype->ctype.attribute->as != rtype->ctype.attribute->as) {
1170 typediff = "different address spaces";
1171 goto Err;
1172 }
1173
1174 /* need to be lazier here */
1175 lbase = examine_pointer_target(ltype);
1176 rbase = examine_pointer_target(rtype);
1177 qual = target_qualifiers(ltype) | target_qualifiers(rtype);
1178
1179 if (lbase == &void_ctype) {
1180 /* XXX: pointers to function should warn here */
1181 ctype = ltype;
1182 goto Qual;
1183
1184 }
1185 if (rbase == &void_ctype) {
1186 /* XXX: pointers to function should warn here */
1187 ctype = rtype;
1188 goto Qual;
1189 }
1190 /* XXX: that should be pointer to composite */
1191 ctype = ltype;
1192 typediff = type_difference(&ltype->ctype, &rtype->ctype,
1193 qual, qual);
1194 if (!typediff)
1195 goto Qual;
1196 goto Err;
1197 }
1198
1199 /* void on void, struct on same struct, union on same union */
1200 if (ltype == rtype) {
1201 ctype = ltype;
1202 goto out;
1203 }
1204 typediff = "different base types";
1205
1206 Err:
1207 expression_error(expr, "incompatible types in conditional expression (%s)", typediff);
1208 return NULL;
1209
1210 out:
1211 expr->ctype = ctype;
1212 return ctype;
1213
1214 Qual:
1215 if (qual & ~ctype->ctype.modifiers) {
1216 struct symbol *sym = alloc_symbol(ctype->pos, SYM_PTR);
1217 *sym = *ctype;
1218 sym->ctype.modifiers |= qual;
1219 ctype = sym;
1220 }
1221 *true = cast_to(*true, ctype);
1222 expr->cond_false = cast_to(expr->cond_false, ctype);
1223 goto out;
1224 }
1225
1226 /* FP assignments can not do modulo or bit operations */
1227 static int compatible_float_op(int op)
1228 {
1229 return op == SPECIAL_ADD_ASSIGN ||
1230 op == SPECIAL_SUB_ASSIGN ||
1231 op == SPECIAL_MUL_ASSIGN ||
1232 op == SPECIAL_DIV_ASSIGN;
1233 }
1234
1235 static int evaluate_assign_op(struct expression *expr)
1236 {
1237 struct symbol *target = expr->left->ctype;
1238 struct symbol *source = expr->right->ctype;
1239 struct symbol *t, *s;
1240 int tclass = classify_type(target, &t);
1241 int sclass = classify_type(source, &s);
1242 int op = expr->op;
1243
1244 if (tclass & sclass & TYPE_NUM) {
1245 if (tclass & TYPE_FLOAT && !compatible_float_op(op)) {
1246 expression_error(expr, "invalid assignment");
1247 return 0;
1248 }
1249 if (tclass & TYPE_RESTRICT) {
1250 if (!restricted_binop(op, t)) {
1251 warning(expr->pos, "bad assignment (%s) to %s",
1252 show_special(op), show_typename(t));
1253 expr->right = cast_to(expr->right, target);
1254 return 0;
1255 }
1256 /* allowed assignments unfoul */
1257 if (sclass & TYPE_FOULED && unfoul(s) == t)
1258 goto Cast;
1259 if (!restricted_value(expr->right, t))
1260 return 1;
1261 } else if (!(sclass & TYPE_RESTRICT))
1262 goto Cast;
1263 /* source and target would better be identical restricted */
1264 if (t == s)
1265 return 1;
1266 warning(expr->pos, "invalid assignment: %s", show_special(op));
1267 info(expr->pos, " left side has type %s", show_typename(t));
1268 info(expr->pos, " right side has type %s", show_typename(s));
1269 expr->right = cast_to(expr->right, target);
1270 return 0;
1271 }
1272 if (tclass == TYPE_PTR && is_int(sclass)) {
1273 if (op == SPECIAL_ADD_ASSIGN || op == SPECIAL_SUB_ASSIGN) {
1274 unrestrict(expr->right, sclass, &s);
1275 evaluate_ptr_add(expr, s);
1276 return 1;
1277 }
1278 expression_error(expr, "invalid pointer assignment");
1279 return 0;
1280 }
1281
1282 expression_error(expr, "invalid assignment");
1283 return 0;
1284
1285 Cast:
1286 expr->right = cast_to(expr->right, target);
1287 return 1;
1288 }
1289
1290 static int whitelist_pointers(struct symbol *t1, struct symbol *t2)
1291 {
1292 if (t1 == t2)
1293 return 0; /* yes, 0 - we don't want a cast_to here */
1294 if (t1 == &void_ctype)
1295 return 1;
1296 if (t2 == &void_ctype)
1297 return 1;
1298 if (classify_type(t1, &t1) != TYPE_NUM)
1299 return 0;
1300 if (classify_type(t2, &t2) != TYPE_NUM)
1301 return 0;
1302 if (t1 == t2)
1303 return 1;
1304 if (t1->ctype.modifiers & t2->ctype.modifiers & MOD_CHAR)
1305 return 1;
1306 if ((t1->ctype.modifiers ^ t2->ctype.modifiers) & MOD_SIZE)
1307 return 0;
1308 return !Wtypesign;
1309 }
1310
1311 static int compatible_assignment_types(struct expression *expr, struct symbol *target,
1312 struct expression **rp, const char *where)
1313 {
1314 const char *typediff;
1315 struct symbol *source = degenerate(*rp);
1316 struct symbol *t, *s;
1317 int tclass = classify_type(target, &t);
1318 int sclass = classify_type(source, &s);
1319
1320 if (tclass & sclass & TYPE_NUM) {
1321 if (tclass & TYPE_RESTRICT) {
1322 /* allowed assignments unfoul */
1323 if (sclass & TYPE_FOULED && unfoul(s) == t)
1324 goto Cast;
1325 if (!restricted_value(*rp, target))
1326 return 1;
1327 if (s == t)
1328 return 1;
1329 } else if (!(sclass & TYPE_RESTRICT))
1330 goto Cast;
1331 typediff = "different base types";
1332 goto Err;
1333 }
1334
1335 if (tclass == TYPE_PTR) {
1336 unsigned long mod1, mod2;
1337 struct symbol *b1, *b2;
1338 // NULL pointer is always OK
1339 int is_null = is_null_pointer_constant(*rp);
1340 if (is_null) {
1341 if (is_null == 2)
1342 bad_null(*rp);
1343 goto Cast;
1344 }
1345 if (!(sclass & TYPE_PTR)) {
1346 typediff = "different base types";
1347 goto Err;
1348 }
1349 b1 = examine_pointer_target(t);
1350 b2 = examine_pointer_target(s);
1351 mod1 = target_qualifiers(t);
1352 mod2 = target_qualifiers(s);
1353 if (whitelist_pointers(b1, b2)) {
1354 /*
1355 * assignments to/from void * are OK, provided that
1356 * we do not remove qualifiers from pointed to [C]
1357 * or mix address spaces [sparse].
1358 */
1359 if (t->ctype.attribute->as != s->ctype.attribute->as) {
1360 typediff = "different address spaces";
1361 goto Err;
1362 }
1363 if (mod2 & ~mod1) {
1364 typediff = "different modifiers";
1365 goto Err;
1366 }
1367 goto Cast;
1368 }
1369 /* It's OK if the target is more volatile or const than the source */
1370 typediff = type_difference(&t->ctype, &s->ctype, 0, mod1);
1371 if (typediff)
1372 goto Err;
1373 return 1;
1374 }
1375
1376 if ((tclass & TYPE_COMPOUND) && s == t)
1377 return 1;
1378
1379 if (tclass & TYPE_NUM) {
1380 /* XXX: need to turn into comparison with NULL */
1381 if (t == &bool_ctype && (sclass & TYPE_PTR))
1382 goto Cast;
1383 typediff = "different base types";
1384 goto Err;
1385 }
1386 typediff = "invalid types";
1387
1388 Err:
1389 warning(expr->pos, "incorrect type in %s (%s)", where, typediff);
1390 info(expr->pos, " expected %s", show_typename(target));
1391 info(expr->pos, " got %s", show_typename(source));
1392 *rp = cast_to(*rp, target);
1393 return 0;
1394 Cast:
1395 *rp = cast_to(*rp, target);
1396 return 1;
1397 }
1398
1399 static void mark_assigned(struct expression *expr)
1400 {
1401 struct symbol *sym;
1402
1403 if (!expr)
1404 return;
1405 switch (expr->type) {
1406 case EXPR_SYMBOL:
1407 sym = expr->symbol;
1408 if (!sym)
1409 return;
1410 if (sym->type != SYM_NODE)
1411 return;
1412 sym->ctype.modifiers |= MOD_ASSIGNED;
1413 return;
1414
1415 case EXPR_BINOP:
1416 mark_assigned(expr->left);
1417 mark_assigned(expr->right);
1418 return;
1419 case EXPR_CAST:
1420 case EXPR_FORCE_CAST:
1421 mark_assigned(expr->cast_expression);
1422 return;
1423 case EXPR_SLICE:
1424 mark_assigned(expr->base);
1425 return;
1426 default:
1427 /* Hmm? */
1428 return;
1429 }
1430 }
1431
1432 static void evaluate_assign_to(struct expression *left, struct symbol *type)
1433 {
1434 if (type->ctype.modifiers & MOD_CONST)
1435 expression_error(left, "assignment to const expression");
1436
1437 /* We know left is an lvalue, so it's a "preop-*" */
1438 mark_assigned(left->unop);
1439 }
1440
1441 static struct symbol *evaluate_assignment(struct expression *expr)
1442 {
1443 struct expression *left = expr->left;
1444 struct expression *where = expr;
1445 struct symbol *ltype;
1446
1447 if (!lvalue_expression(left)) {
1448 expression_error(expr, "not an lvalue");
1449 return NULL;
1450 }
1451
1452 ltype = left->ctype;
1453
1454 if (expr->op != '=') {
1455 if (!evaluate_assign_op(expr))
1456 return NULL;
1457 } else {
1458 if (!compatible_assignment_types(where, ltype, &expr->right, "assignment"))
1459 return NULL;
1460 }
1461
1462 evaluate_assign_to(left, ltype);
1463
1464 expr->ctype = ltype;
1465 return ltype;
1466 }
1467
1468 static void examine_fn_arguments(struct symbol *fn)
1469 {
1470 struct symbol *s;
1471
1472 FOR_EACH_PTR(fn->arguments, s) {
1473 struct symbol *arg = evaluate_symbol(s);
1474 /* Array/function arguments silently degenerate into pointers */
1475 if (arg) {
1476 struct symbol *ptr;
1477 switch(arg->type) {
1478 case SYM_ARRAY:
1479 case SYM_FN:
1480 ptr = alloc_symbol(s->pos, SYM_PTR);
1481 if (arg->type == SYM_ARRAY)
1482 ptr->ctype = arg->ctype;
1483 else
1484 ptr->ctype.base_type = arg;
1485 merge_attr(&ptr->ctype, &s->ctype);
1486 ptr->ctype.modifiers |= s->ctype.modifiers & MOD_PTRINHERIT;
1487
1488 s->ctype.base_type = ptr;
1489 s->ctype.attribute = &null_attr;
1490 s->ctype.modifiers &= ~MOD_PTRINHERIT;
1491 s->bit_size = 0;
1492 s->examined = 0;
1493 examine_symbol_type(s);
1494 break;
1495 default:
1496 /* nothing */
1497 break;
1498 }
1499 }
1500 } END_FOR_EACH_PTR(s);
1501 }
1502
1503 static struct symbol *convert_to_as_mod(struct symbol *sym, int as, int mod)
1504 {
1505 /* Take the modifiers of the pointer, and apply them to the member */
1506 mod |= sym->ctype.modifiers;
1507 if (sym->ctype.attribute->as != as || sym->ctype.modifiers != mod) {
1508 struct symbol *newsym = alloc_symbol(sym->pos, SYM_NODE);
1509 *newsym = *sym;
1510 attr_set_as(&newsym->ctype, as);
1511 newsym->ctype.modifiers = mod;
1512 sym = newsym;
1513 }
1514 return sym;
1515 }
1516
1517 static struct symbol *create_pointer(struct expression *expr, struct symbol *sym, int degenerate)
1518 {
1519 struct symbol *node = alloc_symbol(expr->pos, SYM_NODE);
1520 struct symbol *ptr = alloc_symbol(expr->pos, SYM_PTR);
1521
1522 node->ctype.base_type = ptr;
1523 ptr->bit_size = bits_in_pointer;
1524 ptr->ctype.alignment = pointer_alignment;
1525
1526 node->bit_size = bits_in_pointer;
1527 node->ctype.alignment = pointer_alignment;
1528
1529 access_symbol(sym);
1530 if (sym->ctype.modifiers & MOD_REGISTER) {
1531 warning(expr->pos, "taking address of 'register' variable '%s'", show_ident(sym->ident));
1532 sym->ctype.modifiers &= ~MOD_REGISTER;
1533 }
1534 if (sym->type == SYM_NODE) {
1535 merge_attr(&ptr->ctype, &sym->ctype);
1536 ptr->ctype.modifiers |= sym->ctype.modifiers & MOD_PTRINHERIT;
1537 sym = sym->ctype.base_type;
1538 }
1539 if (degenerate && sym->type == SYM_ARRAY) {
1540 merge_attr(&ptr->ctype, &sym->ctype);
1541 ptr->ctype.modifiers |= sym->ctype.modifiers & MOD_PTRINHERIT;
1542 sym = sym->ctype.base_type;
1543 }
1544 ptr->ctype.base_type = sym;
1545
1546 return node;
1547 }
1548
1549 /* Arrays degenerate into pointers on pointer arithmetic */
1550 static struct symbol *degenerate(struct expression *expr)
1551 {
1552 struct symbol *ctype, *base;
1553
1554 if (!expr)
1555 return NULL;
1556 ctype = expr->ctype;
1557 if (!ctype)
1558 return NULL;
1559 base = examine_symbol_type(ctype);
1560 if (ctype->type == SYM_NODE)
1561 base = ctype->ctype.base_type;
1562 /*
1563 * Arrays degenerate into pointers to the entries, while
1564 * functions degenerate into pointers to themselves.
1565 * If array was part of non-lvalue compound, we create a copy
1566 * of that compound first and then act as if we were dealing with
1567 * the corresponding field in there.
1568 */
1569 switch (base->type) {
1570 case SYM_ARRAY:
1571 if (expr->type == EXPR_SLICE) {
1572 struct symbol *a = alloc_symbol(expr->pos, SYM_NODE);
1573 struct expression *e0, *e1, *e2, *e3, *e4;
1574
1575 a->ctype.base_type = expr->base->ctype;
1576 a->bit_size = expr->base->ctype->bit_size;
1577 a->array_size = expr->base->ctype->array_size;
1578
1579 e0 = alloc_expression(expr->pos, EXPR_SYMBOL);
1580 e0->symbol = a;
1581 e0->ctype = &lazy_ptr_ctype;
1582
1583 e1 = alloc_expression(expr->pos, EXPR_PREOP);
1584 e1->unop = e0;
1585 e1->op = '*';
1586 e1->ctype = expr->base->ctype; /* XXX */
1587
1588 e2 = alloc_expression(expr->pos, EXPR_ASSIGNMENT);
1589 e2->left = e1;
1590 e2->right = expr->base;
1591 e2->op = '=';
1592 e2->ctype = expr->base->ctype;
1593
1594 if (expr->r_bitpos) {
1595 e3 = alloc_expression(expr->pos, EXPR_BINOP);
1596 e3->op = '+';
1597 e3->left = e0;
1598 e3->right = alloc_const_expression(expr->pos,
1599 bits_to_bytes(expr->r_bitpos));
1600 e3->ctype = &lazy_ptr_ctype;
1601 } else {
1602 e3 = e0;
1603 }
1604
1605 e4 = alloc_expression(expr->pos, EXPR_COMMA);
1606 e4->left = e2;
1607 e4->right = e3;
1608 e4->ctype = &lazy_ptr_ctype;
1609
1610 expr->unop = e4;
1611 expr->type = EXPR_PREOP;
1612 expr->op = '*';
1613 }
1614 case SYM_FN:
1615 if (expr->op != '*' || expr->type != EXPR_PREOP) {
1616 expression_error(expr, "strange non-value function or array");
1617 return &bad_ctype;
1618 }
1619 *expr = *expr->unop;
1620 ctype = create_pointer(expr, ctype, 1);
1621 expr->ctype = ctype;
1622 default:
1623 /* nothing */;
1624 }
1625 return ctype;
1626 }
1627
1628 static struct symbol *evaluate_addressof(struct expression *expr)
1629 {
1630 struct expression *op = expr->unop;
1631 struct symbol *ctype;
1632
1633 if (op->op != '*' || op->type != EXPR_PREOP) {
1634 expression_error(expr, "not addressable");
1635 return NULL;
1636 }
1637 ctype = op->ctype;
1638 *expr = *op->unop;
1639 expr->flags = 0;
1640
1641 if (expr->type == EXPR_SYMBOL) {
1642 struct symbol *sym = expr->symbol;
1643 sym->ctype.modifiers |= MOD_ADDRESSABLE;
1644 }
1645
1646 /*
1647 * symbol expression evaluation is lazy about the type
1648 * of the sub-expression, so we may have to generate
1649 * the type here if so..
1650 */
1651 if (expr->ctype == &lazy_ptr_ctype) {
1652 ctype = create_pointer(expr, ctype, 0);
1653 expr->ctype = ctype;
1654 }
1655 return expr->ctype;
1656 }
1657
1658
1659 static struct symbol *evaluate_dereference(struct expression *expr)
1660 {
1661 struct expression *op = expr->unop;
1662 struct symbol *ctype = op->ctype, *node, *target;
1663
1664 /* Simplify: *&(expr) => (expr) */
1665 if (op->type == EXPR_PREOP && op->op == '&') {
1666 *expr = *op->unop;
1667 expr->flags = 0;
1668 return expr->ctype;
1669 }
1670
1671 /* Dereferencing a node drops all the node information. */
1672 if (ctype->type == SYM_NODE)
1673 ctype = ctype->ctype.base_type;
1674
1675 node = alloc_symbol(expr->pos, SYM_NODE);
1676 target = ctype->ctype.base_type;
1677
1678 switch (ctype->type) {
1679 default:
1680 expression_error(expr, "cannot dereference this type");
1681 return NULL;
1682 case SYM_PTR:
1683 node->ctype.modifiers = target->ctype.modifiers & MOD_SPECIFIER;
1684 merge_type(node, ctype);
1685 break;
1686
1687 case SYM_ARRAY:
1688 if (!lvalue_expression(op)) {
1689 expression_error(op, "non-lvalue array??");
1690 return NULL;
1691 }
1692
1693 /* Do the implied "addressof" on the array */
1694 *op = *op->unop;
1695
1696 /*
1697 * When an array is dereferenced, we need to pick
1698 * up the attributes of the original node too..
1699 */
1700 merge_type(node, op->ctype);
1701 merge_type(node, ctype);
1702 break;
1703 }
1704
1705 node->bit_size = target->bit_size;
1706 node->array_size = target->array_size;
1707
1708 expr->ctype = node;
1709 return node;
1710 }
1711
1712 /*
1713 * Unary post-ops: x++ and x--
1714 */
1715 static struct symbol *evaluate_postop(struct expression *expr)
1716 {
1717 struct expression *op = expr->unop;
1718 struct symbol *ctype = op->ctype;
1719 int class = classify_type(ctype, &ctype);
1720 int multiply = 0;
1721
1722 if (!class || class & TYPE_COMPOUND) {
1723 expression_error(expr, "need scalar for ++/--");
1724 return NULL;
1725 }
1726 if (!lvalue_expression(expr->unop)) {
1727 expression_error(expr, "need lvalue expression for ++/--");
1728 return NULL;
1729 }
1730
1731 if ((class & TYPE_RESTRICT) && restricted_unop(expr->op, &ctype))
1732 unrestrict(expr, class, &ctype);
1733
1734 if (class & TYPE_NUM) {
1735 multiply = 1;
1736 } else if (class == TYPE_PTR) {
1737 struct symbol *target = examine_pointer_target(ctype);
1738 if (!is_function(target))
1739 multiply = bits_to_bytes(target->bit_size);
1740 }
1741
1742 if (multiply) {
1743 evaluate_assign_to(op, op->ctype);
1744 expr->op_value = multiply;
1745 expr->ctype = ctype;
1746 return ctype;
1747 }
1748
1749 expression_error(expr, "bad argument type for ++/--");
1750 return NULL;
1751 }
1752
1753 static struct symbol *evaluate_sign(struct expression *expr)
1754 {
1755 struct symbol *ctype = expr->unop->ctype;
1756 int class = classify_type(ctype, &ctype);
1757 if (expr->flags && !(expr->unop->flags & Int_const_expr))
1758 expr->flags = 0;
1759 /* should be an arithmetic type */
1760 if (!(class & TYPE_NUM))
1761 return bad_expr_type(expr);
1762 if (class & TYPE_RESTRICT)
1763 goto Restr;
1764 Normal:
1765 if (!(class & TYPE_FLOAT)) {
1766 ctype = integer_promotion(ctype);
1767 expr->unop = cast_to(expr->unop, ctype);
1768 } else if (expr->op != '~') {
1769 /* no conversions needed */
1770 } else {
1771 return bad_expr_type(expr);
1772 }
1773 if (expr->op == '+')
1774 *expr = *expr->unop;
1775 expr->ctype = ctype;
1776 return ctype;
1777 Restr:
1778 if (restricted_unop(expr->op, &ctype))
1779 unrestrict(expr, class, &ctype);
1780 goto Normal;
1781 }
1782
1783 static struct symbol *evaluate_preop(struct expression *expr)
1784 {
1785 struct symbol *ctype = expr->unop->ctype;
1786
1787 switch (expr->op) {
1788 case '(':
1789 *expr = *expr->unop;
1790 return ctype;
1791
1792 case '+':
1793 case '-':
1794 case '~':
1795 return evaluate_sign(expr);
1796
1797 case '*':
1798 return evaluate_dereference(expr);
1799
1800 case '&':
1801 return evaluate_addressof(expr);
1802
1803 case SPECIAL_INCREMENT:
1804 case SPECIAL_DECREMENT:
1805 /*
1806 * From a type evaluation standpoint the preops are
1807 * the same as the postops
1808 */
1809 return evaluate_postop(expr);
1810
1811 case '!':
1812 if (expr->flags && !(expr->unop->flags & Int_const_expr))
1813 expr->flags = 0;
1814 if (is_safe_type(ctype))
1815 warning(expr->pos, "testing a 'safe expression'");
1816 if (is_float_type(ctype)) {
1817 struct expression *arg = expr->unop;
1818 expr->type = EXPR_COMPARE;
1819 expr->op = SPECIAL_EQUAL;
1820 expr->left = arg;
1821 expr->right = alloc_expression(expr->pos, EXPR_FVALUE);
1822 expr->right->ctype = ctype;
1823 expr->right->fvalue = 0;
1824 } else if (is_fouled_type(ctype)) {
1825 warning(expr->pos, "%s degrades to integer",
1826 show_typename(ctype->ctype.base_type));
1827 }
1828 /* the result is int [6.5.3.3(5)]*/
1829 ctype = &int_ctype;
1830 break;
1831
1832 default:
1833 break;
1834 }
1835 expr->ctype = ctype;
1836 return ctype;
1837 }
1838
1839 static struct symbol *find_identifier(struct ident *ident, struct symbol_list *_list, int *offset)
1840 {
1841 struct ptr_list *head = (struct ptr_list *)_list;
1842 struct ptr_list *list = head;
1843
1844 if (!head)
1845 return NULL;
1846 do {
1847 int i;
1848 for (i = 0; i < list->nr; i++) {
1849 struct symbol *sym = (struct symbol *) list->list[i];
1850 if (sym->ident) {
1851 if (sym->ident != ident)
1852 continue;
1853 *offset = sym->offset;
1854 return sym;
1855 } else {
1856 struct symbol *ctype = sym->ctype.base_type;
1857 struct symbol *sub;
1858 if (!ctype)
1859 continue;
1860 if (ctype->type != SYM_UNION && ctype->type != SYM_STRUCT)
1861 continue;
1862 sub = find_identifier(ident, ctype->symbol_list, offset);
1863 if (!sub)
1864 continue;
1865 *offset += sym->offset;
1866 return sub;
1867 }
1868 }
1869 } while ((list = list->next) != head);
1870 return NULL;
1871 }
1872
1873 static struct expression *evaluate_offset(struct expression *expr, unsigned long offset)
1874 {
1875 struct expression *add;
1876
1877 /*
1878 * Create a new add-expression
1879 *
1880 * NOTE! Even if we just add zero, we need a new node
1881 * for the member pointer, since it has a different
1882 * type than the original pointer. We could make that
1883 * be just a cast, but the fact is, a node is a node,
1884 * so we might as well just do the "add zero" here.
1885 */
1886 add = alloc_expression(expr->pos, EXPR_BINOP);
1887 add->op = '+';
1888 add->left = expr;
1889 add->right = alloc_expression(expr->pos, EXPR_VALUE);
1890 add->right->ctype = &int_ctype;
1891 add->right->value = offset;
1892
1893 /*
1894 * The ctype of the pointer will be lazily evaluated if
1895 * we ever take the address of this member dereference..
1896 */
1897 add->ctype = &lazy_ptr_ctype;
1898 return add;
1899 }
1900
1901 /* structure/union dereference */
1902 static struct symbol *evaluate_member_dereference(struct expression *expr)
1903 {
1904 int offset;
1905 struct symbol *ctype, *member;
1906 struct expression *deref = expr->deref, *add;
1907 struct ident *ident = expr->member;
1908 unsigned int mod;
1909 int address_space;
1910
1911 if (!evaluate_expression(deref))
1912 return NULL;
1913 if (!ident) {
1914 expression_error(expr, "bad member name");
1915 return NULL;
1916 }
1917
1918 ctype = deref->ctype;
1919 examine_symbol_type(ctype);
1920 address_space = ctype->ctype.attribute->as;
1921 mod = ctype->ctype.modifiers;
1922 if (ctype->type == SYM_NODE) {
1923 ctype = ctype->ctype.base_type;
1924 address_space |= ctype->ctype.attribute->as;
1925 mod |= ctype->ctype.modifiers;
1926 }
1927 if (!ctype || (ctype->type != SYM_STRUCT && ctype->type != SYM_UNION)) {
1928 expression_error(expr, "expected structure or union");
1929 return NULL;
1930 }
1931 offset = 0;
1932 member = find_identifier(ident, ctype->symbol_list, &offset);
1933 if (!member) {
1934 const char *type = ctype->type == SYM_STRUCT ? "struct" : "union";
1935 const char *name = "<unnamed>";
1936 int namelen = 9;
1937 if (ctype->ident) {
1938 name = ctype->ident->name;
1939 namelen = ctype->ident->len;
1940 }
1941 if (ctype->symbol_list)
1942 expression_error(expr, "no member '%s' in %s %.*s",
1943 show_ident(ident), type, namelen, name);
1944 else
1945 expression_error(expr, "using member '%s' in "
1946 "incomplete %s %.*s", show_ident(ident),
1947 type, namelen, name);
1948 return NULL;
1949 }
1950
1951 /*
1952 * The member needs to take on the address space and modifiers of
1953 * the "parent" type.
1954 */
1955 member = convert_to_as_mod(member, address_space, mod);
1956 ctype = get_base_type(member);
1957
1958 if (!lvalue_expression(deref)) {
1959 if (deref->type != EXPR_SLICE) {
1960 expr->base = deref;
1961 expr->r_bitpos = 0;
1962 } else {
1963 expr->base = deref->base;
1964 expr->r_bitpos = deref->r_bitpos;
1965 }
1966 expr->r_bitpos += bytes_to_bits(offset);
1967 expr->type = EXPR_SLICE;
1968 expr->r_nrbits = member->bit_size;
1969 expr->r_bitpos += member->bit_offset;
1970 expr->ctype = member;
1971 return member;
1972 }
1973
1974 deref = deref->unop;
1975 expr->deref = deref;
1976
1977 add = evaluate_offset(deref, offset);
1978 expr->type = EXPR_PREOP;
1979 expr->op = '*';
1980 expr->unop = add;
1981
1982 expr->ctype = member;
1983 return member;
1984 }
1985
1986 static int is_promoted(struct expression *expr)
1987 {
1988 while (1) {
1989 switch (expr->type) {
1990 case EXPR_BINOP:
1991 case EXPR_SELECT:
1992 case EXPR_CONDITIONAL:
1993 return 1;
1994 case EXPR_COMMA:
1995 expr = expr->right;
1996 continue;
1997 case EXPR_PREOP:
1998 switch (expr->op) {
1999 case '(':
2000 expr = expr->unop;
2001 continue;
2002 case '+':
2003 case '-':
2004 case '~':
2005 return 1;
2006 default:
2007 return 0;
2008 }
2009 default:
2010 return 0;
2011 }
2012 }
2013 }
2014
2015
2016 static struct symbol *evaluate_cast(struct expression *);
2017
2018 static struct symbol *evaluate_type_information(struct expression *expr)
2019 {
2020 struct symbol *sym = expr->cast_type;
2021 if (!sym) {
2022 sym = evaluate_expression(expr->cast_expression);
2023 if (!sym)
2024 return NULL;
2025 /*
2026 * Expressions of restricted types will possibly get
2027 * promoted - check that here
2028 */
2029 if (is_restricted_type(sym)) {
2030 if (sym->bit_size < bits_in_int && is_promoted(expr))
2031 sym = &int_ctype;
2032 } else if (is_fouled_type(sym)) {
2033 sym = &int_ctype;
2034 }
2035 }
2036 examine_symbol_type(sym);
2037 if (is_bitfield_type(sym)) {
2038 expression_error(expr, "trying to examine bitfield type");
2039 return NULL;
2040 }
2041 return sym;
2042 }
2043
2044 static struct symbol *evaluate_sizeof(struct expression *expr)
2045 {
2046 struct symbol *type;
2047 int size;
2048
2049 type = evaluate_type_information(expr);
2050 if (!type)
2051 return NULL;
2052
2053 size = type->bit_size;
2054
2055 if (size < 0 && is_void_type(type)) {
2056 warning(expr->pos, "expression using sizeof(void)");
2057 size = bits_in_char;
2058 }
2059
2060 if (size == 1 && is_bool_type(type)) {
2061 warning(expr->pos, "expression using sizeof bool");
2062 size = bits_in_char;
2063 }
2064
2065 if (is_function(type->ctype.base_type)) {
2066 warning(expr->pos, "expression using sizeof on a function");
2067 size = bits_in_char;
2068 }
2069
2070 if ((size < 0) || (size & (bits_in_char - 1)))
2071 expression_error(expr, "cannot size expression");
2072
2073 expr->type = EXPR_VALUE;
2074 expr->value = bits_to_bytes(size);
2075 expr->taint = 0;
2076 expr->ctype = size_t_ctype;
2077 return size_t_ctype;
2078 }
2079
2080 static struct symbol *evaluate_ptrsizeof(struct expression *expr)
2081 {
2082 struct symbol *type;
2083 int size;
2084
2085 type = evaluate_type_information(expr);
2086 if (!type)
2087 return NULL;
2088
2089 if (type->type == SYM_NODE)
2090 type = type->ctype.base_type;
2091 if (!type)
2092 return NULL;
2093 switch (type->type) {
2094 case SYM_ARRAY:
2095 break;
2096 case SYM_PTR:
2097 type = get_base_type(type);
2098 if (type)
2099 break;
2100 default:
2101 expression_error(expr, "expected pointer expression");
2102 return NULL;
2103 }
2104 size = type->bit_size;
2105 if (size & (bits_in_char-1))
2106 size = 0;
2107 expr->type = EXPR_VALUE;
2108 expr->value = bits_to_bytes(size);
2109 expr->taint = 0;
2110 expr->ctype = size_t_ctype;
2111 return size_t_ctype;
2112 }
2113
2114 static struct symbol *evaluate_alignof(struct expression *expr)
2115 {
2116 struct symbol *type;
2117
2118 type = evaluate_type_information(expr);
2119 if (!type)
2120 return NULL;
2121
2122 expr->type = EXPR_VALUE;
2123 expr->value = type->ctype.alignment;
2124 expr->taint = 0;
2125 expr->ctype = size_t_ctype;
2126 return size_t_ctype;
2127 }
2128
2129 static int evaluate_arguments(struct symbol *f, struct symbol *fn, struct expression_list *head)
2130 {
2131 struct expression *expr;
2132 struct symbol_list *argument_types = fn->arguments;
2133 struct symbol *argtype;
2134 int i = 1;
2135
2136 PREPARE_PTR_LIST(argument_types, argtype);
2137 FOR_EACH_PTR (head, expr) {
2138 struct expression **p = THIS_ADDRESS(expr);
2139 struct symbol *ctype, *target;
2140 ctype = evaluate_expression(expr);
2141
2142 if (!ctype)
2143 return 0;
2144
2145 target = argtype;
2146 if (!target) {
2147 struct symbol *type;
2148 int class = classify_type(ctype, &type);
2149 if (is_int(class)) {
2150 *p = cast_to(expr, integer_promotion(type));
2151 } else if (class & TYPE_FLOAT) {
2152 unsigned long mod = type->ctype.modifiers;
2153 if (!(mod & (MOD_LONG_ALL)))
2154 *p = cast_to(expr, &double_ctype);
2155 } else if (class & TYPE_PTR) {
2156 if (expr->ctype == &null_ctype)
2157 *p = cast_to(expr, &ptr_ctype);
2158 else
2159 degenerate(expr);
2160 }
2161 } else if (!target->forced_arg){
2162 static char where[30];
2163 examine_symbol_type(target);
2164 sprintf(where, "argument %d", i);
2165 compatible_assignment_types(expr, target, p, where);
2166 }
2167
2168 i++;
2169 NEXT_PTR_LIST(argtype);
2170 } END_FOR_EACH_PTR(expr);
2171 FINISH_PTR_LIST(argtype);
2172 return 1;
2173 }
2174
2175 static struct symbol *find_struct_ident(struct symbol *ctype, struct ident *ident)
2176 {
2177 struct symbol *sym;
2178
2179 FOR_EACH_PTR(ctype->symbol_list, sym) {
2180 if (sym->ident == ident)
2181 return sym;
2182 } END_FOR_EACH_PTR(sym);
2183 return NULL;
2184 }
2185
2186 static void convert_index(struct expression *e)
2187 {
2188 struct expression *child = e->idx_expression;
2189 unsigned from = e->idx_from;
2190 unsigned to = e->idx_to + 1;
2191 e->type = EXPR_POS;
2192 e->init_offset = from * bits_to_bytes(e->ctype->bit_size);
2193 e->init_nr = to - from;
2194 e->init_expr = child;
2195 }
2196
2197 static void convert_ident(struct expression *e)
2198 {
2199 struct expression *child = e->ident_expression;
2200 struct symbol *sym = e->field;
2201 e->type = EXPR_POS;
2202 e->init_offset = sym->offset;
2203 e->init_nr = 1;
2204 e->init_expr = child;
2205 }
2206
2207 static void convert_designators(struct expression *e)
2208 {
2209 while (e) {
2210 if (e->type == EXPR_INDEX)
2211 convert_index(e);
2212 else if (e->type == EXPR_IDENTIFIER)
2213 convert_ident(e);
2214 else
2215 break;
2216 e = e->init_expr;
2217 }
2218 }
2219
2220 static void excess(struct expression *e, const char *s)
2221 {
2222 warning(e->pos, "excessive elements in %s initializer", s);
2223 }
2224
2225 /*
2226 * implicit designator for the first element
2227 */
2228 static struct expression *first_subobject(struct symbol *ctype, int class,
2229 struct expression **v)
2230 {
2231 struct expression *e = *v, *new;
2232
2233 if (ctype->type == SYM_NODE)
2234 ctype = ctype->ctype.base_type;
2235
2236 if (class & TYPE_PTR) { /* array */
2237 if (!ctype->bit_size)
2238 return NULL;
2239 new = alloc_expression(e->pos, EXPR_INDEX);
2240 new->idx_expression = e;
2241 new->ctype = ctype->ctype.base_type;
2242 } else {
2243 struct symbol *field, *p;
2244 PREPARE_PTR_LIST(ctype->symbol_list, p);
2245 while (p && !p->ident && is_bitfield_type(p))
2246 NEXT_PTR_LIST(p);
2247 field = p;
2248 FINISH_PTR_LIST(p);
2249 if (!field)
2250 return NULL;
2251 new = alloc_expression(e->pos, EXPR_IDENTIFIER);
2252 new->ident_expression = e;
2253 new->field = new->ctype = field;
2254 }
2255 *v = new;
2256 return new;
2257 }
2258
2259 /*
2260 * sanity-check explicit designators; return the innermost one or NULL
2261 * in case of error. Assign types.
2262 */
2263 static struct expression *check_designators(struct expression *e,
2264 struct symbol *ctype)
2265 {
2266 struct expression *last = NULL;
2267 const char *err;
2268 while (1) {
2269 if (ctype->type == SYM_NODE)
2270 ctype = ctype->ctype.base_type;
2271 if (e->type == EXPR_INDEX) {
2272 struct symbol *type;
2273 if (ctype->type != SYM_ARRAY) {
2274 err = "array index in non-array";
2275 break;
2276 }
2277 type = ctype->ctype.base_type;
2278 if (ctype->bit_size >= 0 && type->bit_size >= 0) {
2279 unsigned offset = e->idx_to * type->bit_size;
2280 if (offset >= ctype->bit_size) {
2281 err = "index out of bounds in";
2282 break;
2283 }
2284 }
2285 e->ctype = ctype = type;
2286 ctype = type;
2287 last = e;
2288 if (!e->idx_expression) {
2289 err = "invalid";
2290 break;
2291 }
2292 e = e->idx_expression;
2293 } else if (e->type == EXPR_IDENTIFIER) {
2294 if (ctype->type != SYM_STRUCT && ctype->type != SYM_UNION) {
2295 err = "field name not in struct or union";
2296 break;
2297 }
2298 ctype = find_struct_ident(ctype, e->expr_ident);
2299 if (!ctype) {
2300 err = "unknown field name in";
2301 break;
2302 }
2303 e->field = e->ctype = ctype;
2304 last = e;
2305 if (!e->ident_expression) {
2306 err = "invalid";
2307 break;
2308 }
2309 e = e->ident_expression;
2310 } else if (e->type == EXPR_POS) {
2311 err = "internal front-end error: EXPR_POS in";
2312 break;
2313 } else
2314 return last;
2315 }
2316 expression_error(e, "%s initializer", err);
2317 return NULL;
2318 }
2319
2320 /*
2321 * choose the next subobject to initialize.
2322 *
2323 * Get designators for next element, switch old ones to EXPR_POS.
2324 * Return the resulting expression or NULL if we'd run out of subobjects.
2325 * The innermost designator is returned in *v. Designators in old
2326 * are assumed to be already sanity-checked.
2327 */
2328 static struct expression *next_designators(struct expression *old,
2329 struct symbol *ctype,
2330 struct expression *e, struct expression **v)
2331 {
2332 struct expression *new = NULL;
2333
2334 if (!old)
2335 return NULL;
2336 if (old->type == EXPR_INDEX) {
2337 struct expression *copy;
2338 unsigned n;
2339
2340 copy = next_designators(old->idx_expression,
2341 old->ctype, e, v);
2342 if (!copy) {
2343 n = old->idx_to + 1;
2344 if (n * old->ctype->bit_size == ctype->bit_size) {
2345 convert_index(old);
2346 return NULL;
2347 }
2348 copy = e;
2349 *v = new = alloc_expression(e->pos, EXPR_INDEX);
2350 } else {
2351 n = old->idx_to;
2352 new = alloc_expression(e->pos, EXPR_INDEX);
2353 }
2354
2355 new->idx_from = new->idx_to = n;
2356 new->idx_expression = copy;
2357 new->ctype = old->ctype;
2358 convert_index(old);
2359 } else if (old->type == EXPR_IDENTIFIER) {
2360 struct expression *copy;
2361 struct symbol *field;
2362
2363 copy = next_designators(old->ident_expression,
2364 old->ctype, e, v);
2365 if (!copy) {
2366 field = old->field->next_subobject;
2367 if (!field) {
2368 convert_ident(old);
2369 return NULL;
2370 }
2371 copy = e;
2372 *v = new = alloc_expression(e->pos, EXPR_IDENTIFIER);
2373 } else {
2374 field = old->field;
2375 new = alloc_expression(e->pos, EXPR_IDENTIFIER);
2376 }
2377
2378 new->field = field;
2379 new->expr_ident = field->ident;
2380 new->ident_expression = copy;
2381 new->ctype = field;
2382 convert_ident(old);
2383 }
2384 return new;
2385 }
2386
2387 static int handle_simple_initializer(struct expression **ep, int nested,
2388 int class, struct symbol *ctype);
2389
2390 /*
2391 * deal with traversing subobjects [6.7.8(17,18,20)]
2392 */
2393 static void handle_list_initializer(struct expression *expr,
2394 int class, struct symbol *ctype)
2395 {
2396 struct expression *e, *last = NULL, *top = NULL, *next;
2397 int jumped = 0;
2398
2399 FOR_EACH_PTR(expr->expr_list, e) {
2400 struct expression **v;
2401 struct symbol *type;
2402 int lclass;
2403
2404 if (e->type != EXPR_INDEX && e->type != EXPR_IDENTIFIER) {
2405 struct symbol *struct_sym;
2406 if (!top) {
2407 top = e;
2408 last = first_subobject(ctype, class, &top);
2409 } else {
2410 last = next_designators(last, ctype, e, &top);
2411 }
2412 if (!last) {
2413 excess(e, class & TYPE_PTR ? "array" :
2414 "struct or union");
2415 DELETE_CURRENT_PTR(e);
2416 continue;
2417 }
2418 struct_sym = ctype->type == SYM_NODE ? ctype->ctype.base_type : ctype;
2419 if (Wdesignated_init && struct_sym->designated_init)
2420 warning(e->pos, "%s%.*s%spositional init of field in %s %s, declared with attribute designated_init",
2421 ctype->ident ? "in initializer for " : "",
2422 ctype->ident ? ctype->ident->len : 0,
2423 ctype->ident ? ctype->ident->name : "",
2424 ctype->ident ? ": " : "",
2425 get_type_name(struct_sym->type),
2426 show_ident(struct_sym->ident));
2427 if (jumped) {
2428 warning(e->pos, "advancing past deep designator");
2429 jumped = 0;
2430 }
2431 REPLACE_CURRENT_PTR(e, last);
2432 } else {
2433 next = check_designators(e, ctype);
2434 if (!next) {
2435 DELETE_CURRENT_PTR(e);
2436 continue;
2437 }
2438 top = next;
2439 /* deeper than one designator? */
2440 jumped = top != e;
2441 convert_designators(last);
2442 last = e;
2443 }
2444
2445 found:
2446 lclass = classify_type(top->ctype, &type);
2447 if (top->type == EXPR_INDEX)
2448 v = &top->idx_expression;
2449 else
2450 v = &top->ident_expression;
2451
2452 if (handle_simple_initializer(v, 1, lclass, top->ctype))
2453 continue;
2454
2455 if (!(lclass & TYPE_COMPOUND)) {
2456 warning(e->pos, "bogus scalar initializer");
2457 DELETE_CURRENT_PTR(e);
2458 continue;
2459 }
2460
2461 next = first_subobject(type, lclass, v);
2462 if (next) {
2463 warning(e->pos, "missing braces around initializer");
2464 top = next;
2465 goto found;
2466 }
2467
2468 DELETE_CURRENT_PTR(e);
2469 excess(e, lclass & TYPE_PTR ? "array" : "struct or union");
2470
2471 } END_FOR_EACH_PTR(e);
2472
2473 convert_designators(last);
2474 expr->ctype = ctype;
2475 }
2476
2477 static int is_string_literal(struct expression **v)
2478 {
2479 struct expression *e = *v;
2480 while (e && e->type == EXPR_PREOP && e->op == '(')
2481 e = e->unop;
2482 if (!e || e->type != EXPR_STRING)
2483 return 0;
2484 if (e != *v && Wparen_string)
2485 warning(e->pos,
2486 "array initialized from parenthesized string constant");
2487 *v = e;
2488 return 1;
2489 }
2490
2491 /*
2492 * We want a normal expression, possibly in one layer of braces. Warn
2493 * if the latter happens inside a list (it's legal, but likely to be
2494 * an effect of screwup). In case of anything not legal, we are definitely
2495 * having an effect of screwup, so just fail and let the caller warn.
2496 */
2497 static struct expression *handle_scalar(struct expression *e, int nested)
2498 {
2499 struct expression *v = NULL, *p;
2500 int count = 0;
2501
2502 /* normal case */
2503 if (e->type != EXPR_INITIALIZER)
2504 return e;
2505
2506 FOR_EACH_PTR(e->expr_list, p) {
2507 if (!v)
2508 v = p;
2509 count++;
2510 } END_FOR_EACH_PTR(p);
2511 if (count != 1)
2512 return NULL;
2513 switch(v->type) {
2514 case EXPR_INITIALIZER:
2515 case EXPR_INDEX:
2516 case EXPR_IDENTIFIER:
2517 return NULL;
2518 default:
2519 break;
2520 }
2521 if (nested)
2522 warning(e->pos, "braces around scalar initializer");
2523 return v;
2524 }
2525
2526 /*
2527 * deal with the cases that don't care about subobjects:
2528 * scalar <- assignment expression, possibly in braces [6.7.8(11)]
2529 * character array <- string literal, possibly in braces [6.7.8(14)]
2530 * struct or union <- assignment expression of compatible type [6.7.8(13)]
2531 * compound type <- initializer list in braces [6.7.8(16)]
2532 * The last one punts to handle_list_initializer() which, in turn will call
2533 * us for individual elements of the list.
2534 *
2535 * We do not handle 6.7.8(15) (wide char array <- wide string literal) for
2536 * the lack of support of wide char stuff in general.
2537 *
2538 * One note: we need to take care not to evaluate a string literal until
2539 * we know that we *will* handle it right here. Otherwise we would screw
2540 * the cases like struct { struct {char s[10]; ...} ...} initialized with
2541 * { "string", ...} - we need to preserve that string literal recognizable
2542 * until we dig into the inner struct.
2543 */
2544 static int handle_simple_initializer(struct expression **ep, int nested,
2545 int class, struct symbol *ctype)
2546 {
2547 int is_string = is_string_type(ctype);
2548 struct expression *e = *ep, *p;
2549 struct symbol *type;
2550
2551 if (!e)
2552 return 0;
2553
2554 /* scalar */
2555 if (!(class & TYPE_COMPOUND)) {
2556 e = handle_scalar(e, nested);
2557 if (!e)
2558 return 0;
2559 *ep = e;
2560 if (!evaluate_expression(e))
2561 return 1;
2562 compatible_assignment_types(e, ctype, ep, "initializer");
2563 return 1;
2564 }
2565
2566 /*
2567 * sublist; either a string, or we dig in; the latter will deal with
2568 * pathologies, so we don't need anything fancy here.
2569 */
2570 if (e->type == EXPR_INITIALIZER) {
2571 if (is_string) {
2572 struct expression *v = NULL;
2573 int count = 0;
2574
2575 FOR_EACH_PTR(e->expr_list, p) {
2576 if (!v)
2577 v = p;
2578 count++;
2579 } END_FOR_EACH_PTR(p);
2580 if (count == 1 && is_string_literal(&v)) {
2581 *ep = e = v;
2582 goto String;
2583 }
2584 }
2585 handle_list_initializer(e, class, ctype);
2586 return 1;
2587 }
2588
2589 /* string */
2590 if (is_string_literal(&e)) {
2591 /* either we are doing array of char, or we'll have to dig in */
2592 if (is_string) {
2593 *ep = e;
2594 goto String;
2595 }
2596 return 0;
2597 }
2598 /* struct or union can be initialized by compatible */
2599 if (class != TYPE_COMPOUND)
2600 return 0;
2601 type = evaluate_expression(e);
2602 if (!type)
2603 return 0;
2604 if (ctype->type == SYM_NODE)
2605 ctype = ctype->ctype.base_type;
2606 if (type->type == SYM_NODE)
2607 type = type->ctype.base_type;
2608 if (ctype == type)
2609 return 1;
2610 return 0;
2611
2612 String:
2613 p = alloc_expression(e->pos, EXPR_STRING);
2614 *p = *e;
2615 type = evaluate_expression(p);
2616 if (ctype->bit_size != -1) {
2617 if (ctype->bit_size + bits_in_char < type->bit_size)
2618 warning(e->pos,
2619 "too long initializer-string for array of char");
2620 else if (Winit_cstring && ctype->bit_size + bits_in_char == type->bit_size) {
2621 warning(e->pos,
2622 "too long initializer-string for array of char(no space for nul char)");
2623 }
2624 }
2625 *ep = p;
2626 return 1;
2627 }
2628
2629 static void evaluate_initializer(struct symbol *ctype, struct expression **ep)
2630 {
2631 struct symbol *type;
2632 int class = classify_type(ctype, &type);
2633 if (!handle_simple_initializer(ep, 0, class, ctype))
2634 expression_error(*ep, "invalid initializer");
2635 }
2636
2637 static struct symbol *evaluate_cast(struct expression *expr)
2638 {
2639 struct expression *target = expr->cast_expression;
2640 struct symbol *ctype;
2641 struct symbol *t1, *t2;
2642 int class1, class2;
2643 int as1 = 0, as2 = 0;
2644
2645 if (!target)
2646 return NULL;
2647
2648 /*
2649 * Special case: a cast can be followed by an
2650 * initializer, in which case we need to pass
2651 * the type value down to that initializer rather
2652 * than trying to evaluate it as an expression
2653 *
2654 * A more complex case is when the initializer is
2655 * dereferenced as part of a post-fix expression.
2656 * We need to produce an expression that can be dereferenced.
2657 */
2658 if (target->type == EXPR_INITIALIZER) {
2659 struct symbol *sym = expr->cast_type;
2660 struct expression *addr = alloc_expression(expr->pos, EXPR_SYMBOL);
2661
2662 sym->initializer = target;
2663 evaluate_symbol(sym);
2664
2665 addr->ctype = &lazy_ptr_ctype; /* Lazy eval */
2666 addr->symbol = sym;
2667
2668 expr->type = EXPR_PREOP;
2669 expr->op = '*';
2670 expr->unop = addr;
2671 expr->ctype = sym;
2672
2673 return sym;
2674 }
2675
2676 ctype = examine_symbol_type(expr->cast_type);
2677 expr->ctype = ctype;
2678 expr->cast_type = ctype;
2679
2680 evaluate_expression(target);
2681 degenerate(target);
2682
2683 class1 = classify_type(ctype, &t1);
2684
2685 /* cast to non-integer type -> not an integer constant expression */
2686 if (!is_int(class1))
2687 expr->flags = 0;
2688 /* if argument turns out to be not an integer constant expression *and*
2689 it was not a floating literal to start with -> too bad */
2690 else if (expr->flags == Int_const_expr &&
2691 !(target->flags & Int_const_expr))
2692 expr->flags = 0;
2693 /*
2694 * You can always throw a value away by casting to
2695 * "void" - that's an implicit "force". Note that
2696 * the same is _not_ true of "void *".
2697 */
2698 if (t1 == &void_ctype)
2699 goto out;
2700
2701 if (class1 & (TYPE_COMPOUND | TYPE_FN))
2702 warning(expr->pos, "cast to non-scalar");
2703
2704 t2 = target->ctype;
2705 if (!t2) {
2706 expression_error(expr, "cast from unknown type");
2707 goto out;
2708 }
2709 class2 = classify_type(t2, &t2);
2710
2711 if (class2 & TYPE_COMPOUND)
2712 warning(expr->pos, "cast from non-scalar");
2713
2714 if (expr->type == EXPR_FORCE_CAST)
2715 goto out;
2716
2717 /* allowed cast unfouls */
2718 if (class2 & TYPE_FOULED)
2719 t2 = unfoul(t2);
2720
2721 if (t1 != t2) {
2722 if (class1 & TYPE_RESTRICT)
2723 warning(expr->pos, "cast to %s",
2724 show_typename(t1));
2725 if (class2 & TYPE_RESTRICT)
2726 warning(expr->pos, "cast from %s",
2727 show_typename(t2));
2728 }
2729
2730 if (t1 == &ulong_ctype)
2731 as1 = -1;
2732 else if (class1 == TYPE_PTR) {
2733 examine_pointer_target(t1);
2734 as1 = t1->ctype.attribute->as;
2735 }
2736
2737 if (t2 == &ulong_ctype)
2738 as2 = -1;
2739 else if (class2 == TYPE_PTR) {
2740 examine_pointer_target(t2);
2741 as2 = t2->ctype.attribute->as;
2742 }
2743
2744 if (!as1 && as2 > 0)
2745 warning(expr->pos, "cast removes address space of expression");
2746 if (as1 > 0 && as2 > 0 && as1 != as2)
2747 warning(expr->pos, "cast between address spaces (<asn:%d>-><asn:%d>)", as2, as1);
2748 if (as1 > 0 && !as2 &&
2749 !is_null_pointer_constant(target) && Wcast_to_as)
2750 warning(expr->pos,
2751 "cast adds address space to expression (<asn:%d>)", as1);
2752
2753 if (!(t1->ctype.modifiers & MOD_PTRINHERIT) && class1 == TYPE_PTR &&
2754 !as1 && (target->flags & Int_const_expr)) {
2755 if (t1->ctype.base_type == &void_ctype) {
2756 if (is_zero_constant(target)) {
2757 /* NULL */
2758 expr->type = EXPR_VALUE;
2759 expr->ctype = &null_ctype;
2760 expr->value = 0;
2761 return ctype;
2762 }
2763 }
2764 }
2765 out:
2766 return ctype;
2767 }
2768
2769 /*
2770 * Evaluate a call expression with a symbol. This
2771 * should expand inline functions, and evaluate
2772 * builtins.
2773 */
2774 static int evaluate_symbol_call(struct expression *expr)
2775 {
2776 struct expression *fn = expr->fn;
2777 struct symbol *ctype = fn->ctype;
2778
2779 if (fn->type != EXPR_PREOP)
2780 return 0;
2781
2782 if (ctype->op && ctype->op->evaluate)
2783 return ctype->op->evaluate(expr);
2784
2785 if (ctype->ctype.modifiers & MOD_INLINE) {
2786 int ret;
2787 struct symbol *curr = current_fn;
2788
2789 if (ctype->definition)
2790 ctype = ctype->definition;
2791
2792 current_fn = ctype->ctype.base_type;
2793
2794 ret = inline_function(expr, ctype);
2795
2796 /* restore the old function */
2797 current_fn = curr;
2798 return ret;
2799 }
2800
2801 return 0;
2802 }
2803
2804 static struct symbol *evaluate_call(struct expression *expr)
2805 {
2806 int args, fnargs;
2807 struct symbol *ctype, *sym;
2808 struct expression *fn = expr->fn;
2809 struct expression_list *arglist = expr->args;
2810
2811 if (!evaluate_expression(fn))
2812 return NULL;
2813 sym = ctype = fn->ctype;
2814 if (ctype->type == SYM_NODE)
2815 ctype = ctype->ctype.base_type;
2816 if (ctype->type == SYM_PTR)
2817 ctype = get_base_type(ctype);
2818
2819 if (ctype->type != SYM_FN) {
2820 struct expression *arg;
2821 expression_error(expr, "not a function %s",
2822 show_ident(sym->ident));
2823 /* do typechecking in arguments */
2824 FOR_EACH_PTR (arglist, arg) {
2825 evaluate_expression(arg);
2826 } END_FOR_EACH_PTR(arg);
2827 return NULL;
2828 }
2829
2830 examine_fn_arguments(ctype);
2831 if (sym->type == SYM_NODE && fn->type == EXPR_PREOP &&
2832 sym->op && sym->op->args) {
2833 if (!sym->op->args(expr))
2834 return NULL;
2835 } else {
2836 if (!evaluate_arguments(sym, ctype, arglist))
2837 return NULL;
2838 args = expression_list_size(expr->args);
2839 fnargs = symbol_list_size(ctype->arguments);
2840 if (args < fnargs)
2841 expression_error(expr,
2842 "not enough arguments for function %s",
2843 show_ident(sym->ident));
2844 if (args > fnargs && !ctype->variadic)
2845 expression_error(expr,
2846 "too many arguments for function %s",
2847 show_ident(sym->ident));
2848 }
2849 if (sym->type == SYM_NODE) {
2850 if (evaluate_symbol_call(expr))
2851 return expr->ctype;
2852 }
2853 expr->ctype = ctype->ctype.base_type;
2854 return expr->ctype;
2855 }
2856
2857 static struct symbol *evaluate_offsetof(struct expression *expr)
2858 {
2859 struct expression *e = expr->down;
2860 struct symbol *ctype = expr->in;
2861 int class;
2862
2863 if (expr->op == '.') {
2864 struct symbol *field;
2865 int offset = 0;
2866 if (!ctype) {
2867 expression_error(expr, "expected structure or union");
2868 return NULL;
2869 }
2870 examine_symbol_type(ctype);
2871 class = classify_type(ctype, &ctype);
2872 if (class != TYPE_COMPOUND) {
2873 expression_error(expr, "expected structure or union");
2874 return NULL;
2875 }
2876
2877 field = find_identifier(expr->ident, ctype->symbol_list, &offset);
2878 if (!field) {
2879 expression_error(expr, "unknown member");
2880 return NULL;
2881 }
2882 ctype = field;
2883 expr->type = EXPR_VALUE;
2884 expr->flags = Int_const_expr;
2885 expr->value = offset;
2886 expr->taint = 0;
2887 expr->ctype = size_t_ctype;
2888 } else {
2889 if (!ctype) {
2890 expression_error(expr, "expected structure or union");
2891 return NULL;
2892 }
2893 examine_symbol_type(ctype);
2894 class = classify_type(ctype, &ctype);
2895 if (class != (TYPE_COMPOUND | TYPE_PTR)) {
2896 expression_error(expr, "expected array");
2897 return NULL;
2898 }
2899 ctype = ctype->ctype.base_type;
2900 if (!expr->index) {
2901 expr->type = EXPR_VALUE;
2902 expr->flags = Int_const_expr;
2903 expr->value = 0;
2904 expr->taint = 0;
2905 expr->ctype = size_t_ctype;
2906 } else {
2907 struct expression *idx = expr->index, *m;
2908 struct symbol *i_type = evaluate_expression(idx);
2909 int i_class = classify_type(i_type, &i_type);
2910 if (!is_int(i_class)) {
2911 expression_error(expr, "non-integer index");
2912 return NULL;
2913 }
2914 unrestrict(idx, i_class, &i_type);
2915 idx = cast_to(idx, size_t_ctype);
2916 m = alloc_const_expression(expr->pos,
2917 bits_to_bytes(ctype->bit_size));
2918 m->ctype = size_t_ctype;
2919 m->flags = Int_const_expr;
2920 expr->type = EXPR_BINOP;
2921 expr->left = idx;
2922 expr->right = m;
2923 expr->op = '*';
2924 expr->ctype = size_t_ctype;
2925 expr->flags = m->flags & idx->flags & Int_const_expr;
2926 }
2927 }
2928 if (e) {
2929 struct expression *copy = __alloc_expression(0);
2930 *copy = *expr;
2931 if (e->type == EXPR_OFFSETOF)
2932 e->in = ctype;
2933 if (!evaluate_expression(e))
2934 return NULL;
2935 expr->type = EXPR_BINOP;
2936 expr->flags = e->flags & copy->flags & Int_const_expr;
2937 expr->op = '+';
2938 expr->ctype = size_t_ctype;
2939 expr->left = copy;
2940 expr->right = e;
2941 }
2942 return size_t_ctype;
2943 }
2944
2945 struct symbol *evaluate_expression(struct expression *expr)
2946 {
2947 if (!expr)
2948 return NULL;
2949 if (expr->ctype)
2950 return expr->ctype;
2951
2952 switch (expr->type) {
2953 case EXPR_VALUE:
2954 case EXPR_FVALUE:
2955 expression_error(expr, "value expression without a type");
2956 return NULL;
2957 case EXPR_STRING:
2958 return evaluate_string(expr);
2959 case EXPR_SYMBOL:
2960 return evaluate_symbol_expression(expr);
2961 case EXPR_BINOP:
2962 if (!evaluate_expression(expr->left))
2963 return NULL;
2964 if (!evaluate_expression(expr->right))
2965 return NULL;
2966 return evaluate_binop(expr);
2967 case EXPR_LOGICAL:
2968 return evaluate_logical(expr);
2969 case EXPR_COMMA:
2970 evaluate_expression(expr->left);
2971 if (!evaluate_expression(expr->right))
2972 return NULL;
2973 return evaluate_comma(expr);
2974 case EXPR_COMPARE:
2975 if (!evaluate_expression(expr->left))
2976 return NULL;
2977 if (!evaluate_expression(expr->right))
2978 return NULL;
2979 return evaluate_compare(expr);
2980 case EXPR_ASSIGNMENT:
2981 if (!evaluate_expression(expr->left))
2982 return NULL;
2983 if (!evaluate_expression(expr->right))
2984 return NULL;
2985 return evaluate_assignment(expr);
2986 case EXPR_PREOP:
2987 if (!evaluate_expression(expr->unop))
2988 return NULL;
2989 return evaluate_preop(expr);
2990 case EXPR_POSTOP:
2991 if (!evaluate_expression(expr->unop))
2992 return NULL;
2993 return evaluate_postop(expr);
2994 case EXPR_CAST:
2995 case EXPR_FORCE_CAST:
2996 case EXPR_IMPLIED_CAST:
2997 return evaluate_cast(expr);
2998 case EXPR_SIZEOF:
2999 return evaluate_sizeof(expr);
3000 case EXPR_PTRSIZEOF:
3001 return evaluate_ptrsizeof(expr);
3002 case EXPR_ALIGNOF:
3003 return evaluate_alignof(expr);
3004 case EXPR_DEREF:
3005 return evaluate_member_dereference(expr);
3006 case EXPR_CALL:
3007 return evaluate_call(expr);
3008 case EXPR_SELECT:
3009 case EXPR_CONDITIONAL:
3010 return evaluate_conditional_expression(expr);
3011 case EXPR_STATEMENT:
3012 expr->ctype = evaluate_statement(expr->statement);
3013 return expr->ctype;
3014
3015 case EXPR_LABEL:
3016 expr->ctype = &ptr_ctype;
3017 return &ptr_ctype;
3018
3019 case EXPR_TYPE:
3020 /* Evaluate the type of the symbol .. */
3021 evaluate_symbol(expr->symbol);
3022 /* .. but the type of the _expression_ is a "type" */
3023 expr->ctype = &type_ctype;
3024 return &type_ctype;
3025
3026 case EXPR_OFFSETOF:
3027 return evaluate_offsetof(expr);
3028
3029 /* These can not exist as stand-alone expressions */
3030 case EXPR_INITIALIZER:
3031 case EXPR_IDENTIFIER:
3032 case EXPR_INDEX:
3033 case EXPR_POS:
3034 expression_error(expr, "internal front-end error: initializer in expression");
3035 return NULL;
3036 case EXPR_SLICE:
3037 expression_error(expr, "internal front-end error: SLICE re-evaluated");
3038 return NULL;
3039 }
3040 return NULL;
3041 }
3042
3043 static void check_duplicates(struct symbol *sym)
3044 {
3045 int declared = 0;
3046 struct symbol *next = sym;
3047
3048 while ((next = next->same_symbol) != NULL) {
3049 const char *typediff;
3050 evaluate_symbol(next);
3051 declared++;
3052 typediff = type_difference(&sym->ctype, &next->ctype, 0, 0);
3053 if (typediff) {
3054 sparse_error(sym->pos, "symbol '%s' redeclared with different type (originally declared at %s:%d) - %s",
3055 show_ident(sym->ident),
3056 stream_name(next->pos.stream), next->pos.line, typediff);
3057 return;
3058 }
3059 }
3060 if (!declared) {
3061 unsigned long mod = sym->ctype.modifiers;
3062 if (mod & (MOD_STATIC | MOD_REGISTER))
3063 return;
3064 if (!(mod & MOD_TOPLEVEL))
3065 return;
3066 if (!Wdecl)
3067 return;
3068 if (sym->ident == &main_ident)
3069 return;
3070 warning(sym->pos, "symbol '%s' was not declared. Should it be static?", show_ident(sym->ident));
3071 }
3072 }
3073
3074 static struct symbol *evaluate_symbol(struct symbol *sym)
3075 {
3076 struct symbol *base_type;
3077
3078 if (!sym)
3079 return sym;
3080 if (sym->evaluated)
3081 return sym;
3082 sym->evaluated = 1;
3083
3084 sym = examine_symbol_type(sym);
3085 base_type = get_base_type(sym);
3086 if (!base_type)
3087 return NULL;
3088
3089 /* Evaluate the initializers */
3090 if (sym->initializer)
3091 evaluate_initializer(sym, &sym->initializer);
3092
3093 /* And finally, evaluate the body of the symbol too */
3094 if (base_type->type == SYM_FN) {
3095 struct symbol *curr = current_fn;
3096
3097 if (sym->definition && sym->definition != sym)
3098 return evaluate_symbol(sym->definition);
3099
3100 current_fn = base_type;
3101
3102 examine_fn_arguments(base_type);
3103 if (!base_type->stmt && base_type->inline_stmt)
3104 uninline(sym);
3105 if (base_type->stmt)
3106 evaluate_statement(base_type->stmt);
3107
3108 current_fn = curr;
3109 }
3110
3111 return base_type;
3112 }
3113
3114 void evaluate_symbol_list(struct symbol_list *list)
3115 {
3116 struct symbol *sym;
3117
3118 FOR_EACH_PTR(list, sym) {
3119 evaluate_symbol(sym);
3120 check_duplicates(sym);
3121 } END_FOR_EACH_PTR(sym);
3122 }
3123
3124 static struct symbol *evaluate_return_expression(struct statement *stmt)
3125 {
3126 struct expression *expr = stmt->expression;
3127 struct symbol *fntype;
3128
3129 evaluate_expression(expr);
3130 fntype = current_fn->ctype.base_type;
3131 if (!fntype || fntype == &void_ctype) {
3132 if (expr && expr->ctype != &void_ctype)
3133 expression_error(expr, "return expression in %s function", fntype?"void":"typeless");
3134 if (expr && Wreturn_void)
3135 warning(stmt->pos, "returning void-valued expression");
3136 return NULL;
3137 }
3138
3139 if (!expr) {
3140 sparse_error(stmt->pos, "return with no return value");
3141 return NULL;
3142 }
3143 if (!expr->ctype)
3144 return NULL;
3145 compatible_assignment_types(expr, fntype, &stmt->expression, "return expression");
3146 return NULL;
3147 }
3148
3149 static void evaluate_if_statement(struct statement *stmt)
3150 {
3151 if (!stmt->if_conditional)
3152 return;
3153
3154 evaluate_conditional(stmt->if_conditional, 0);
3155 evaluate_statement(stmt->if_true);
3156 evaluate_statement(stmt->if_false);
3157 }
3158
3159 static void evaluate_iterator(struct statement *stmt)
3160 {
3161 evaluate_symbol_list(stmt->iterator_syms);
3162 evaluate_conditional(stmt->iterator_pre_condition, 1);
3163 evaluate_conditional(stmt->iterator_post_condition,1);
3164 evaluate_statement(stmt->iterator_pre_statement);
3165 evaluate_statement(stmt->iterator_statement);
3166 evaluate_statement(stmt->iterator_post_statement);
3167 }
3168
3169 static void verify_output_constraint(struct expression *expr, const char *constraint)
3170 {
3171 switch (*constraint) {
3172 case '=': /* Assignment */
3173 case '+': /* Update */
3174 break;
3175 default:
3176 expression_error(expr, "output constraint is not an assignment constraint (\"%s\")", constraint);
3177 }
3178 }
3179
3180 static void verify_input_constraint(struct expression *expr, const char *constraint)
3181 {
3182 switch (*constraint) {
3183 case '=': /* Assignment */
3184 case '+': /* Update */
3185 expression_error(expr, "input constraint with assignment (\"%s\")", constraint);
3186 }
3187 }
3188
3189 static void evaluate_asm_statement(struct statement *stmt)
3190 {
3191 struct expression *expr;
3192 struct symbol *sym;
3193 int state;
3194
3195 expr = stmt->asm_string;
3196 if (!expr || expr->type != EXPR_STRING) {
3197 sparse_error(stmt->pos, "need constant string for inline asm");
3198 return;
3199 }
3200
3201 state = 0;
3202 FOR_EACH_PTR(stmt->asm_outputs, expr) {
3203 switch (state) {
3204 case 0: /* Identifier */
3205 state = 1;
3206 continue;
3207
3208 case 1: /* Constraint */
3209 state = 2;
3210 if (!expr || expr->type != EXPR_STRING) {
3211 sparse_error(expr ? expr->pos : stmt->pos, "asm output constraint is not a string");
3212 *THIS_ADDRESS(expr) = NULL;
3213 continue;
3214 }
3215 verify_output_constraint(expr, expr->string->data);
3216 continue;
3217
3218 case 2: /* Expression */
3219 state = 0;
3220 if (!evaluate_expression(expr))
3221 return;
3222 if (!lvalue_expression(expr))
3223 warning(expr->pos, "asm output is not an lvalue");
3224 evaluate_assign_to(expr, expr->ctype);
3225 continue;
3226 }
3227 } END_FOR_EACH_PTR(expr);
3228
3229 state = 0;
3230 FOR_EACH_PTR(stmt->asm_inputs, expr) {
3231 switch (state) {
3232 case 0: /* Identifier */
3233 state = 1;
3234 continue;
3235
3236 case 1: /* Constraint */
3237 state = 2;
3238 if (!expr || expr->type != EXPR_STRING) {
3239 sparse_error(expr ? expr->pos : stmt->pos, "asm input constraint is not a string");
3240 *THIS_ADDRESS(expr) = NULL;
3241 continue;
3242 }
3243 verify_input_constraint(expr, expr->string->data);
3244 continue;
3245
3246 case 2: /* Expression */
3247 state = 0;
3248 if (!evaluate_expression(expr))
3249 return;
3250 continue;
3251 }
3252 } END_FOR_EACH_PTR(expr);
3253
3254 FOR_EACH_PTR(stmt->asm_clobbers, expr) {
3255 if (!expr) {
3256 sparse_error(stmt->pos, "bad asm clobbers");
3257 return;
3258 }
3259 if (expr->type == EXPR_STRING)
3260 continue;
3261 expression_error(expr, "asm clobber is not a string");
3262 } END_FOR_EACH_PTR(expr);
3263
3264 FOR_EACH_PTR(stmt->asm_labels, sym) {
3265 if (!sym || sym->type != SYM_LABEL) {
3266 sparse_error(stmt->pos, "bad asm label");
3267 return;
3268 }
3269 } END_FOR_EACH_PTR(sym);
3270 }
3271
3272 static void evaluate_case_statement(struct statement *stmt)
3273 {
3274 evaluate_expression(stmt->case_expression);
3275 evaluate_expression(stmt->case_to);
3276 evaluate_statement(stmt->case_statement);
3277 }
3278
3279 static void check_case_type(struct expression *switch_expr,
3280 struct expression *case_expr,
3281 struct expression **enumcase)
3282 {
3283 struct symbol *switch_type, *case_type;
3284 int sclass, cclass;
3285
3286 if (!case_expr)
3287 return;
3288
3289 switch_type = switch_expr->ctype;
3290 case_type = evaluate_expression(case_expr);
3291
3292 if (!switch_type || !case_type)
3293 goto Bad;
3294 if (enumcase) {
3295 if (*enumcase)
3296 warn_for_different_enum_types(case_expr->pos, case_type, (*enumcase)->ctype);
3297 else if (is_enum_type(case_type))
3298 *enumcase = case_expr;
3299 }
3300
3301 sclass = classify_type(switch_type, &switch_type);
3302 cclass = classify_type(case_type, &case_type);
3303
3304 /* both should be arithmetic */
3305 if (!(sclass & cclass & TYPE_NUM))
3306 goto Bad;
3307
3308 /* neither should be floating */
3309 if ((sclass | cclass) & TYPE_FLOAT)
3310 goto Bad;
3311
3312 /* if neither is restricted, we are OK */
3313 if (!((sclass | cclass) & TYPE_RESTRICT))
3314 return;
3315
3316 if (!restricted_binop_type(SPECIAL_EQUAL, case_expr, switch_expr,
3317 cclass, sclass, case_type, switch_type)) {
3318 unrestrict(case_expr, cclass, &case_type);
3319 unrestrict(switch_expr, sclass, &switch_type);
3320 }
3321 return;
3322
3323 Bad:
3324 expression_error(case_expr, "incompatible types for 'case' statement");
3325 }
3326
3327 static void evaluate_switch_statement(struct statement *stmt)
3328 {
3329 struct symbol *sym;
3330 struct expression *enumcase = NULL;
3331 struct expression **enumcase_holder = &enumcase;
3332 struct expression *sel = stmt->switch_expression;
3333
3334 evaluate_expression(sel);
3335 evaluate_statement(stmt->switch_statement);
3336 if (!sel)
3337 return;
3338 if (sel->ctype && is_enum_type(sel->ctype))
3339 enumcase_holder = NULL; /* Only check cases against switch */
3340
3341 FOR_EACH_PTR(stmt->switch_case->symbol_list, sym) {
3342 struct statement *case_stmt = sym->stmt;
3343 check_case_type(sel, case_stmt->case_expression, enumcase_holder);
3344 check_case_type(sel, case_stmt->case_to, enumcase_holder);
3345 } END_FOR_EACH_PTR(sym);
3346 }
3347
3348 static void evaluate_goto_statement(struct statement *stmt)
3349 {
3350 struct symbol *label = stmt->goto_label;
3351
3352 if (label && !label->stmt)
3353 sparse_error(stmt->pos, "label '%s' was not declared", show_ident(label->ident));
3354
3355 evaluate_expression(stmt->goto_expression);
3356 }
3357
3358 struct symbol *evaluate_statement(struct statement *stmt)
3359 {
3360 if (!stmt)
3361 return NULL;
3362
3363 switch (stmt->type) {
3364 case STMT_DECLARATION: {
3365 struct symbol *s;
3366 FOR_EACH_PTR(stmt->declaration, s) {
3367 evaluate_symbol(s);
3368 } END_FOR_EACH_PTR(s);
3369 return NULL;
3370 }
3371
3372 case STMT_RETURN:
3373 return evaluate_return_expression(stmt);
3374
3375 case STMT_EXPRESSION:
3376 if (!evaluate_expression(stmt->expression))
3377 return NULL;
3378 if (stmt->expression->ctype == &null_ctype)
3379 stmt->expression = cast_to(stmt->expression, &ptr_ctype);
3380 return degenerate(stmt->expression);
3381
3382 case STMT_COMPOUND: {
3383 struct statement *s;
3384 struct symbol *type = NULL;
3385
3386 /* Evaluate the return symbol in the compound statement */
3387 evaluate_symbol(stmt->ret);
3388
3389 /*
3390 * Then, evaluate each statement, making the type of the
3391 * compound statement be the type of the last statement
3392 */
3393 type = evaluate_statement(stmt->args);
3394 FOR_EACH_PTR(stmt->stmts, s) {
3395 type = evaluate_statement(s);
3396 } END_FOR_EACH_PTR(s);
3397 if (!type)
3398 type = &void_ctype;
3399 return type;
3400 }
3401 case STMT_IF:
3402 evaluate_if_statement(stmt);
3403 return NULL;
3404 case STMT_ITERATOR:
3405 evaluate_iterator(stmt);
3406 return NULL;
3407 case STMT_SWITCH:
3408 evaluate_switch_statement(stmt);
3409 return NULL;
3410 case STMT_CASE:
3411 evaluate_case_statement(stmt);
3412 return NULL;
3413 case STMT_LABEL:
3414 return evaluate_statement(stmt->label_statement);
3415 case STMT_GOTO:
3416 evaluate_goto_statement(stmt);
3417 return NULL;
3418 case STMT_NONE:
3419 break;
3420 case STMT_ASM:
3421 evaluate_asm_statement(stmt);
3422 return NULL;
3423 case STMT_CONTEXT:
3424 evaluate_expression(stmt->expression);
3425 return NULL;
3426 case STMT_RANGE:
3427 evaluate_expression(stmt->range_expression);
3428 evaluate_expression(stmt->range_low);
3429 evaluate_expression(stmt->range_high);
3430 return NULL;
3431 }
3432 return NULL;
3433 }
Static analysis for C