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 addr->flags = expr->flags;
74 expr->type = EXPR_PREOP;
75 expr->op = '*';
76 expr->unop = addr;
77 expr->flags = CEF_NONE;
78
79 /* The type of a symbol is the symbol itself! */
80 expr->ctype = sym;
81 return sym;
82 }
83
84 static struct symbol *evaluate_string(struct expression *expr)
85 {
86 struct symbol *sym = alloc_symbol(expr->pos, SYM_NODE);
87 struct symbol *array = alloc_symbol(expr->pos, SYM_ARRAY);
88 struct expression *addr = alloc_expression(expr->pos, EXPR_SYMBOL);
89 struct expression *initstr = alloc_expression(expr->pos, EXPR_STRING);
90 unsigned int length = expr->string->length;
91
92 sym->array_size = alloc_const_expression(expr->pos, length);
93 sym->bit_size = bytes_to_bits(length);
94 sym->ctype.alignment = 1;
95 sym->string = 1;
96 sym->ctype.modifiers = MOD_STATIC;
97 sym->ctype.base_type = array;
98 sym->initializer = initstr;
99
100 initstr->ctype = sym;
101 initstr->string = expr->string;
102
103 array->array_size = sym->array_size;
104 array->bit_size = bytes_to_bits(length);
105 array->ctype.alignment = 1;
106 array->ctype.modifiers = MOD_STATIC;
107 array->ctype.base_type = &char_ctype;
108
109 addr->symbol = sym;
110 addr->ctype = &lazy_ptr_ctype;
111 addr->flags = CEF_ADDR;
112
113 expr->type = EXPR_PREOP;
114 expr->op = '*';
115 expr->unop = addr;
116 expr->ctype = sym;
117 return sym;
118 }
119
120 /* type has come from classify_type and is an integer type */
121 static inline struct symbol *integer_promotion(struct symbol *type)
122 {
123 unsigned long mod = type->ctype.modifiers;
124 int width = type->bit_size;
125
126 /*
127 * Bitfields always promote to the base type,
128 * even if the bitfield might be bigger than
129 * an "int".
130 */
131 if (type->type == SYM_BITFIELD) {
132 type = type->ctype.base_type;
133 }
134 mod = type->ctype.modifiers;
135 if (width < bits_in_int)
136 return &int_ctype;
137
138 /* If char/short has as many bits as int, it still gets "promoted" */
139 if (mod & (MOD_CHAR | MOD_SHORT)) {
140 if (mod & MOD_UNSIGNED)
141 return &uint_ctype;
142 return &int_ctype;
143 }
144 return type;
145 }
146
147 /*
148 * integer part of usual arithmetic conversions:
149 * integer promotions are applied
150 * if left and right are identical, we are done
151 * if signedness is the same, convert one with lower rank
152 * unless unsigned argument has rank lower than signed one, convert the
153 * signed one.
154 * if signed argument is bigger than unsigned one, convert the unsigned.
155 * otherwise, convert signed.
156 *
157 * Leaving aside the integer promotions, that is equivalent to
158 * if identical, don't convert
159 * if left is bigger than right, convert right
160 * if right is bigger than left, convert right
161 * otherwise, if signedness is the same, convert one with lower rank
162 * otherwise convert the signed one.
163 */
164 static struct symbol *bigger_int_type(struct symbol *left, struct symbol *right)
165 {
166 unsigned long lmod, rmod;
167
168 left = integer_promotion(left);
169 right = integer_promotion(right);
170
171 if (left == right)
172 goto left;
173
174 if (left->bit_size > right->bit_size)
175 goto left;
176
177 if (right->bit_size > left->bit_size)
178 goto right;
179
180 lmod = left->ctype.modifiers;
181 rmod = right->ctype.modifiers;
182 if ((lmod ^ rmod) & MOD_UNSIGNED) {
183 if (lmod & MOD_UNSIGNED)
184 goto left;
185 } else if ((lmod & ~rmod) & (MOD_LONG_ALL))
186 goto left;
187 right:
188 left = right;
189 left:
190 return left;
191 }
192
193 static int same_cast_type(struct symbol *orig, struct symbol *new)
194 {
195 return orig->bit_size == new->bit_size &&
196 orig->bit_offset == new->bit_offset;
197 }
198
199 static struct symbol *base_type(struct symbol *node, unsigned long *modp, unsigned long *asp)
200 {
201 unsigned long mod, as;
202
203 mod = 0; as = 0;
204 while (node) {
205 mod |= node->ctype.modifiers;
206 as |= node->ctype.as;
207 if (node->type == SYM_NODE) {
208 node = node->ctype.base_type;
209 continue;
210 }
211 break;
212 }
213 *modp = mod & ~MOD_IGNORE;
214 *asp = as;
215 return node;
216 }
217
218 static int is_same_type(struct expression *expr, struct symbol *new)
219 {
220 struct symbol *old = expr->ctype;
221 unsigned long oldmod, newmod, oldas, newas;
222
223 old = base_type(old, &oldmod, &oldas);
224 new = base_type(new, &newmod, &newas);
225
226 /* Same base type, same address space? */
227 if (old == new && oldas == newas) {
228 unsigned long difmod;
229
230 /* Check the modifier bits. */
231 difmod = (oldmod ^ newmod) & ~MOD_NOCAST;
232
233 /* Exact same type? */
234 if (!difmod)
235 return 1;
236
237 /*
238 * Not the same type, but differs only in "const".
239 * Don't warn about MOD_NOCAST.
240 */
241 if (difmod == MOD_CONST)
242 return 0;
243 }
244 if ((oldmod | newmod) & MOD_NOCAST) {
245 const char *tofrom = "to/from";
246 if (!(newmod & MOD_NOCAST))
247 tofrom = "from";
248 if (!(oldmod & MOD_NOCAST))
249 tofrom = "to";
250 warning(expr->pos, "implicit cast %s nocast type", tofrom);
251 }
252 return 0;
253 }
254
255 static void
256 warn_for_different_enum_types (struct position pos,
257 struct symbol *typea,
258 struct symbol *typeb)
259 {
260 if (!Wenum_mismatch)
261 return;
262 if (typea->type == SYM_NODE)
263 typea = typea->ctype.base_type;
264 if (typeb->type == SYM_NODE)
265 typeb = typeb->ctype.base_type;
266
267 if (typea == typeb)
268 return;
269
270 if (typea->type == SYM_ENUM && typeb->type == SYM_ENUM) {
271 warning(pos, "mixing different enum types");
272 info(pos, " %s versus", show_typename(typea));
273 info(pos, " %s", show_typename(typeb));
274 }
275 }
276
277 static int cast_flags(struct expression *expr, struct expression *target);
278 static struct symbol *cast_to_bool(struct expression *expr);
279
280 /*
281 * This gets called for implicit casts in assignments and
282 * integer promotion. We often want to try to move the
283 * cast down, because the ops involved may have been
284 * implicitly cast up, and we can get rid of the casts
285 * early.
286 */
287 static struct expression * cast_to(struct expression *old, struct symbol *type)
288 {
289 struct expression *expr;
290
291 warn_for_different_enum_types (old->pos, old->ctype, type);
292
293 if (old->ctype != &null_ctype && is_same_type(old, type))
294 return old;
295
296 /*
297 * See if we can simplify the op. Move the cast down.
298 */
299 switch (old->type) {
300 case EXPR_PREOP:
301 if (old->ctype->bit_size < type->bit_size)
302 break;
303 if (old->op == '~') {
304 old->ctype = type;
305 old->unop = cast_to(old->unop, type);
306 return old;
307 }
308 break;
309
310 case EXPR_IMPLIED_CAST:
311 warn_for_different_enum_types(old->pos, old->ctype, type);
312
313 if (old->ctype->bit_size >= type->bit_size) {
314 struct expression *orig = old->cast_expression;
315 if (same_cast_type(orig->ctype, type))
316 return orig;
317 if (old->ctype->bit_offset == type->bit_offset) {
318 old->ctype = type;
319 old->cast_type = type;
320 return old;
321 }
322 }
323 break;
324
325 default:
326 /* nothing */;
327 }
328
329 expr = alloc_expression(old->pos, EXPR_IMPLIED_CAST);
330 expr->ctype = type;
331 expr->cast_type = type;
332 expr->cast_expression = old;
333 expr->flags = cast_flags(expr, old);
334
335 if (is_bool_type(type))
336 cast_to_bool(expr);
337
338 return expr;
339 }
340
341 enum {
342 TYPE_NUM = 1,
343 TYPE_BITFIELD = 2,
344 TYPE_RESTRICT = 4,
345 TYPE_FLOAT = 8,
346 TYPE_PTR = 16,
347 TYPE_COMPOUND = 32,
348 TYPE_FOULED = 64,
349 TYPE_FN = 128,
350 };
351
352 static inline int classify_type(struct symbol *type, struct symbol **base)
353 {
354 static int type_class[SYM_BAD + 1] = {
355 [SYM_PTR] = TYPE_PTR,
356 [SYM_FN] = TYPE_PTR | TYPE_FN,
357 [SYM_ARRAY] = TYPE_PTR | TYPE_COMPOUND,
358 [SYM_STRUCT] = TYPE_COMPOUND,
359 [SYM_UNION] = TYPE_COMPOUND,
360 [SYM_BITFIELD] = TYPE_NUM | TYPE_BITFIELD,
361 [SYM_RESTRICT] = TYPE_NUM | TYPE_RESTRICT,
362 [SYM_FOULED] = TYPE_NUM | TYPE_RESTRICT | TYPE_FOULED,
363 };
364 if (type->type == SYM_NODE)
365 type = type->ctype.base_type;
366 if (type->type == SYM_TYPEOF) {
367 type = evaluate_expression(type->initializer);
368 if (!type)
369 type = &bad_ctype;
370 else if (type->type == SYM_NODE)
371 type = type->ctype.base_type;
372 }
373 if (type->type == SYM_ENUM)
374 type = type->ctype.base_type;
375 *base = type;
376 if (type->type == SYM_BASETYPE) {
377 if (type->ctype.base_type == &int_type)
378 return TYPE_NUM;
379 if (type->ctype.base_type == &fp_type)
380 return TYPE_NUM | TYPE_FLOAT;
381 }
382 return type_class[type->type];
383 }
384
385 #define is_int(class) ((class & (TYPE_NUM | TYPE_FLOAT)) == TYPE_NUM)
386
387 static inline int is_string_type(struct symbol *type)
388 {
389 if (type->type == SYM_NODE)
390 type = type->ctype.base_type;
391 return type->type == SYM_ARRAY && is_byte_type(type->ctype.base_type);
392 }
393
394 static struct symbol *bad_expr_type(struct expression *expr)
395 {
396 sparse_error(expr->pos, "incompatible types for operation (%s)", show_special(expr->op));
397 switch (expr->type) {
398 case EXPR_BINOP:
399 case EXPR_COMPARE:
400 info(expr->pos, " left side has type %s", show_typename(expr->left->ctype));
401 info(expr->pos, " right side has type %s", show_typename(expr->right->ctype));
402 break;
403 case EXPR_PREOP:
404 case EXPR_POSTOP:
405 info(expr->pos, " argument has type %s", show_typename(expr->unop->ctype));
406 break;
407 default:
408 break;
409 }
410
411 expr->flags = CEF_NONE;
412 return expr->ctype = &bad_ctype;
413 }
414
415 static int restricted_value(struct expression *v, struct symbol *type)
416 {
417 if (v->type != EXPR_VALUE)
418 return 1;
419 if (v->value != 0)
420 return 1;
421 return 0;
422 }
423
424 static int restricted_binop(int op, struct symbol *type)
425 {
426 switch (op) {
427 case '&':
428 case '=':
429 case SPECIAL_AND_ASSIGN:
430 case SPECIAL_OR_ASSIGN:
431 case SPECIAL_XOR_ASSIGN:
432 return 1; /* unfoul */
433 case '|':
434 case '^':
435 case '?':
436 return 2; /* keep fouled */
437 case SPECIAL_EQUAL:
438 case SPECIAL_NOTEQUAL:
439 return 3; /* warn if fouled */
440 default:
441 return 0; /* warn */
442 }
443 }
444
445 static int restricted_unop(int op, struct symbol **type)
446 {
447 if (op == '~') {
448 if ((*type)->bit_size < bits_in_int)
449 *type = befoul(*type);
450 return 0;
451 } if (op == '+')
452 return 0;
453 return 1;
454 }
455
456 /* type should be SYM_FOULED */
457 static inline struct symbol *unfoul(struct symbol *type)
458 {
459 return type->ctype.base_type;
460 }
461
462 static struct symbol *restricted_binop_type(int op,
463 struct expression *left,
464 struct expression *right,
465 int lclass, int rclass,
466 struct symbol *ltype,
467 struct symbol *rtype)
468 {
469 struct symbol *ctype = NULL;
470 if (lclass & TYPE_RESTRICT) {
471 if (rclass & TYPE_RESTRICT) {
472 if (ltype == rtype) {
473 ctype = ltype;
474 } else if (lclass & TYPE_FOULED) {
475 if (unfoul(ltype) == rtype)
476 ctype = ltype;
477 } else if (rclass & TYPE_FOULED) {
478 if (unfoul(rtype) == ltype)
479 ctype = rtype;
480 }
481 } else {
482 if (!restricted_value(right, ltype))
483 ctype = ltype;
484 }
485 } else if (!restricted_value(left, rtype))
486 ctype = rtype;
487
488 if (ctype) {
489 switch (restricted_binop(op, ctype)) {
490 case 1:
491 if ((lclass ^ rclass) & TYPE_FOULED)
492 ctype = unfoul(ctype);
493 break;
494 case 3:
495 if (!(lclass & rclass & TYPE_FOULED))
496 break;
497 case 0:
498 ctype = NULL;
499 default:
500 break;
501 }
502 }
503
504 return ctype;
505 }
506
507 static inline void unrestrict(struct expression *expr,
508 int class, struct symbol **ctype)
509 {
510 if (class & TYPE_RESTRICT) {
511 if (class & TYPE_FOULED)
512 *ctype = unfoul(*ctype);
513 warning(expr->pos, "%s degrades to integer",
514 show_typename(*ctype));
515 *ctype = (*ctype)->ctype.base_type; /* get to arithmetic type */
516 }
517 }
518
519 static struct symbol *usual_conversions(int op,
520 struct expression *left,
521 struct expression *right,
522 int lclass, int rclass,
523 struct symbol *ltype,
524 struct symbol *rtype)
525 {
526 struct symbol *ctype;
527
528 warn_for_different_enum_types(right->pos, left->ctype, right->ctype);
529
530 if ((lclass | rclass) & TYPE_RESTRICT)
531 goto Restr;
532
533 Normal:
534 if (!(lclass & TYPE_FLOAT)) {
535 if (!(rclass & TYPE_FLOAT))
536 return bigger_int_type(ltype, rtype);
537 else
538 return rtype;
539 } else if (rclass & TYPE_FLOAT) {
540 unsigned long lmod = ltype->ctype.modifiers;
541 unsigned long rmod = rtype->ctype.modifiers;
542 if (rmod & ~lmod & (MOD_LONG_ALL))
543 return rtype;
544 else
545 return ltype;
546 } else
547 return ltype;
548
549 Restr:
550 ctype = restricted_binop_type(op, left, right,
551 lclass, rclass, ltype, rtype);
552 if (ctype)
553 return ctype;
554
555 unrestrict(left, lclass, <ype);
556 unrestrict(right, rclass, &rtype);
557
558 goto Normal;
559 }
560
561 static inline int lvalue_expression(struct expression *expr)
562 {
563 return expr->type == EXPR_PREOP && expr->op == '*';
564 }
565
566 static struct symbol *evaluate_ptr_add(struct expression *expr, struct symbol *itype)
567 {
568 struct expression *index = expr->right;
569 struct symbol *ctype, *base;
570 int multiply;
571
572 classify_type(degenerate(expr->left), &ctype);
573 base = examine_pointer_target(ctype);
574
575 /*
576 * An address constant +/- an integer constant expression
577 * yields an address constant again [6.6(7)].
578 */
579 if ((expr->left->flags & CEF_ADDR) && (expr->right->flags & CEF_ICE))
580 expr->flags = CEF_ADDR;
581
582 if (!base) {
583 expression_error(expr, "missing type information");
584 return NULL;
585 }
586 if (is_function(base)) {
587 expression_error(expr, "arithmetics on pointers to functions");
588 return NULL;
589 }
590
591 /* Get the size of whatever the pointer points to */
592 multiply = is_void_type(base) ? 1 : bits_to_bytes(base->bit_size);
593
594 if (ctype == &null_ctype)
595 ctype = &ptr_ctype;
596 expr->ctype = ctype;
597
598 if (multiply == 1 && itype->bit_size >= bits_in_pointer)
599 return ctype;
600
601 if (index->type == EXPR_VALUE) {
602 struct expression *val = alloc_expression(expr->pos, EXPR_VALUE);
603 unsigned long long v = index->value, mask;
604 mask = 1ULL << (itype->bit_size - 1);
605 if (v & mask)
606 v |= -mask;
607 else
608 v &= mask - 1;
609 v *= multiply;
610 mask = 1ULL << (bits_in_pointer - 1);
611 v &= mask | (mask - 1);
612 val->value = v;
613 val->ctype = ssize_t_ctype;
614 expr->right = val;
615 return ctype;
616 }
617
618 if (itype->bit_size < bits_in_pointer)
619 index = cast_to(index, ssize_t_ctype);
620
621 if (multiply > 1) {
622 struct expression *val = alloc_expression(expr->pos, EXPR_VALUE);
623 struct expression *mul = alloc_expression(expr->pos, EXPR_BINOP);
624
625 val->ctype = ssize_t_ctype;
626 val->value = multiply;
627
628 mul->op = '*';
629 mul->ctype = ssize_t_ctype;
630 mul->left = index;
631 mul->right = val;
632 index = mul;
633 }
634
635 expr->right = index;
636 return ctype;
637 }
638
639 static void examine_fn_arguments(struct symbol *fn);
640
641 #define MOD_IGN (MOD_VOLATILE | MOD_CONST | MOD_PURE)
642
643 const char *type_difference(struct ctype *c1, struct ctype *c2,
644 unsigned long mod1, unsigned long mod2)
645 {
646 unsigned long as1 = c1->as, as2 = c2->as;
647 struct symbol *t1 = c1->base_type;
648 struct symbol *t2 = c2->base_type;
649 int move1 = 1, move2 = 1;
650 mod1 |= c1->modifiers;
651 mod2 |= c2->modifiers;
652 for (;;) {
653 unsigned long diff;
654 int type;
655 struct symbol *base1 = t1->ctype.base_type;
656 struct symbol *base2 = t2->ctype.base_type;
657
658 /*
659 * FIXME! Collect alignment and context too here!
660 */
661 if (move1) {
662 if (t1 && t1->type != SYM_PTR) {
663 mod1 |= t1->ctype.modifiers;
664 as1 |= t1->ctype.as;
665 }
666 move1 = 0;
667 }
668
669 if (move2) {
670 if (t2 && t2->type != SYM_PTR) {
671 mod2 |= t2->ctype.modifiers;
672 as2 |= t2->ctype.as;
673 }
674 move2 = 0;
675 }
676
677 if (t1 == t2)
678 break;
679 if (!t1 || !t2)
680 return "different types";
681
682 if (t1->type == SYM_NODE || t1->type == SYM_ENUM) {
683 t1 = base1;
684 move1 = 1;
685 if (!t1)
686 return "bad types";
687 continue;
688 }
689
690 if (t2->type == SYM_NODE || t2->type == SYM_ENUM) {
691 t2 = base2;
692 move2 = 1;
693 if (!t2)
694 return "bad types";
695 continue;
696 }
697
698 move1 = move2 = 1;
699 type = t1->type;
700 if (type != t2->type)
701 return "different base types";
702
703 switch (type) {
704 default:
705 sparse_error(t1->pos,
706 "internal error: bad type in derived(%d)",
707 type);
708 return "bad types";
709 case SYM_RESTRICT:
710 return "different base types";
711 case SYM_UNION:
712 case SYM_STRUCT:
713 /* allow definition of incomplete structs and unions */
714 if (t1->ident == t2->ident)
715 return NULL;
716 return "different base types";
717 case SYM_ARRAY:
718 /* XXX: we ought to compare sizes */
719 break;
720 case SYM_PTR:
721 if (as1 != as2)
722 return "different address spaces";
723 /* MOD_SPECIFIER is due to idiocy in parse.c */
724 if ((mod1 ^ mod2) & ~MOD_IGNORE & ~MOD_SPECIFIER)
725 return "different modifiers";
726 /* we could be lazier here */
727 base1 = examine_pointer_target(t1);
728 base2 = examine_pointer_target(t2);
729 mod1 = t1->ctype.modifiers;
730 as1 = t1->ctype.as;
731 mod2 = t2->ctype.modifiers;
732 as2 = t2->ctype.as;
733 break;
734 case SYM_FN: {
735 struct symbol *arg1, *arg2;
736 int i;
737
738 if (as1 != as2)
739 return "different address spaces";
740 if ((mod1 ^ mod2) & ~MOD_IGNORE & ~MOD_SIGNEDNESS)
741 return "different modifiers";
742 mod1 = t1->ctype.modifiers;
743 as1 = t1->ctype.as;
744 mod2 = t2->ctype.modifiers;
745 as2 = t2->ctype.as;
746
747 if (t1->variadic != t2->variadic)
748 return "incompatible variadic arguments";
749 examine_fn_arguments(t1);
750 examine_fn_arguments(t2);
751 PREPARE_PTR_LIST(t1->arguments, arg1);
752 PREPARE_PTR_LIST(t2->arguments, arg2);
753 i = 1;
754 for (;;) {
755 const char *diffstr;
756 if (!arg1 && !arg2)
757 break;
758 if (!arg1 || !arg2)
759 return "different argument counts";
760 diffstr = type_difference(&arg1->ctype,
761 &arg2->ctype,
762 MOD_IGN, MOD_IGN);
763 if (diffstr) {
764 static char argdiff[80];
765 sprintf(argdiff, "incompatible argument %d (%s)", i, diffstr);
766 return argdiff;
767 }
768 NEXT_PTR_LIST(arg1);
769 NEXT_PTR_LIST(arg2);
770 i++;
771 }
772 FINISH_PTR_LIST(arg2);
773 FINISH_PTR_LIST(arg1);
774 break;
775 }
776 case SYM_BASETYPE:
777 if (as1 != as2)
778 return "different address spaces";
779 if (base1 != base2)
780 return "different base types";
781 diff = (mod1 ^ mod2) & ~MOD_IGNORE;
782 if (!diff)
783 return NULL;
784 if (diff & MOD_SIZE)
785 return "different type sizes";
786 else if (diff & ~MOD_SIGNEDNESS)
787 return "different modifiers";
788 else
789 return "different signedness";
790 }
791 t1 = base1;
792 t2 = base2;
793 }
794 if (as1 != as2)
795 return "different address spaces";
796 if ((mod1 ^ mod2) & ~MOD_IGNORE & ~MOD_SIGNEDNESS)
797 return "different modifiers";
798 return NULL;
799 }
800
801 static void bad_null(struct expression *expr)
802 {
803 if (Wnon_pointer_null)
804 warning(expr->pos, "Using plain integer as NULL pointer");
805 }
806
807 static unsigned long target_qualifiers(struct symbol *type)
808 {
809 unsigned long mod = type->ctype.modifiers & MOD_IGN;
810 if (type->ctype.base_type && type->ctype.base_type->type == SYM_ARRAY)
811 mod = 0;
812 return mod;
813 }
814
815 static struct symbol *evaluate_ptr_sub(struct expression *expr)
816 {
817 const char *typediff;
818 struct symbol *ltype, *rtype;
819 struct expression *l = expr->left;
820 struct expression *r = expr->right;
821 struct symbol *lbase;
822
823 classify_type(degenerate(l), <ype);
824 classify_type(degenerate(r), &rtype);
825
826 lbase = examine_pointer_target(ltype);
827 examine_pointer_target(rtype);
828 typediff = type_difference(<ype->ctype, &rtype->ctype,
829 target_qualifiers(rtype),
830 target_qualifiers(ltype));
831 if (typediff)
832 expression_error(expr, "subtraction of different types can't work (%s)", typediff);
833
834 if (is_function(lbase)) {
835 expression_error(expr, "subtraction of functions? Share your drugs");
836 return NULL;
837 }
838
839 expr->ctype = ssize_t_ctype;
840 if (lbase->bit_size > bits_in_char) {
841 struct expression *sub = alloc_expression(expr->pos, EXPR_BINOP);
842 struct expression *div = expr;
843 struct expression *val = alloc_expression(expr->pos, EXPR_VALUE);
844 unsigned long value = bits_to_bytes(lbase->bit_size);
845
846 val->ctype = size_t_ctype;
847 val->value = value;
848
849 if (value & (value-1)) {
850 if (Wptr_subtraction_blows)
851 warning(expr->pos, "potentially expensive pointer subtraction");
852 }
853
854 sub->op = '-';
855 sub->ctype = ssize_t_ctype;
856 sub->left = l;
857 sub->right = r;
858
859 div->op = '/';
860 div->left = sub;
861 div->right = val;
862 }
863
864 return ssize_t_ctype;
865 }
866
867 #define is_safe_type(type) ((type)->ctype.modifiers & MOD_SAFE)
868
869 static struct symbol *evaluate_conditional(struct expression *expr, int iterator)
870 {
871 struct symbol *ctype;
872
873 if (!expr)
874 return NULL;
875
876 if (!iterator && expr->type == EXPR_ASSIGNMENT && expr->op == '=')
877 warning(expr->pos, "assignment expression in conditional");
878
879 ctype = evaluate_expression(expr);
880 if (ctype) {
881 if (is_safe_type(ctype))
882 warning(expr->pos, "testing a 'safe expression'");
883 if (is_func_type(ctype)) {
884 if (Waddress)
885 warning(expr->pos, "the address of %s will always evaluate as true", "a function");
886 } else if (is_array_type(ctype)) {
887 if (Waddress)
888 warning(expr->pos, "the address of %s will always evaluate as true", "an array");
889 } else if (!is_scalar_type(ctype)) {
890 sparse_error(expr->pos, "incorrect type in conditional");
891 info(expr->pos, " got %s", show_typename(ctype));
892 ctype = NULL;
893 }
894 }
895 ctype = degenerate(expr);
896
897 return ctype;
898 }
899
900 static struct symbol *evaluate_logical(struct expression *expr)
901 {
902 if (!evaluate_conditional(expr->left, 0))
903 return NULL;
904 if (!evaluate_conditional(expr->right, 0))
905 return NULL;
906
907 /* the result is int [6.5.13(3), 6.5.14(3)] */
908 expr->ctype = &int_ctype;
909 expr->flags = expr->left->flags & expr->right->flags;
910 expr->flags &= ~(CEF_CONST_MASK | CEF_ADDR);
911 return &int_ctype;
912 }
913
914 static struct symbol *evaluate_binop(struct expression *expr)
915 {
916 struct symbol *ltype, *rtype, *ctype;
917 int lclass = classify_type(expr->left->ctype, <ype);
918 int rclass = classify_type(expr->right->ctype, &rtype);
919 int op = expr->op;
920
921 /* number op number */
922 if (lclass & rclass & TYPE_NUM) {
923 expr->flags = expr->left->flags & expr->right->flags;
924 expr->flags &= ~CEF_CONST_MASK;
925
926 if ((lclass | rclass) & TYPE_FLOAT) {
927 switch (op) {
928 case '+': case '-': case '*': case '/':
929 break;
930 default:
931 return bad_expr_type(expr);
932 }
933 }
934
935 if (op == SPECIAL_LEFTSHIFT || op == SPECIAL_RIGHTSHIFT) {
936 // shifts do integer promotions, but that's it.
937 unrestrict(expr->left, lclass, <ype);
938 unrestrict(expr->right, rclass, &rtype);
939 ctype = ltype = integer_promotion(ltype);
940 rtype = integer_promotion(rtype);
941 } else {
942 // The rest do usual conversions
943 const unsigned left_not = expr->left->type == EXPR_PREOP
944 && expr->left->op == '!';
945 const unsigned right_not = expr->right->type == EXPR_PREOP
946 && expr->right->op == '!';
947 if ((op == '&' || op == '|') && (left_not || right_not))
948 warning(expr->pos, "dubious: %sx %c %sy",
949 left_not ? "!" : "",
950 op,
951 right_not ? "!" : "");
952
953 ltype = usual_conversions(op, expr->left, expr->right,
954 lclass, rclass, ltype, rtype);
955 ctype = rtype = ltype;
956 }
957
958 expr->left = cast_to(expr->left, ltype);
959 expr->right = cast_to(expr->right, rtype);
960 expr->ctype = ctype;
961 return ctype;
962 }
963
964 /* pointer (+|-) integer */
965 if (lclass & TYPE_PTR && is_int(rclass) && (op == '+' || op == '-')) {
966 unrestrict(expr->right, rclass, &rtype);
967 return evaluate_ptr_add(expr, rtype);
968 }
969
970 /* integer + pointer */
971 if (rclass & TYPE_PTR && is_int(lclass) && op == '+') {
972 struct expression *index = expr->left;
973 unrestrict(index, lclass, <ype);
974 expr->left = expr->right;
975 expr->right = index;
976 return evaluate_ptr_add(expr, ltype);
977 }
978
979 /* pointer - pointer */
980 if (lclass & rclass & TYPE_PTR && expr->op == '-')
981 return evaluate_ptr_sub(expr);
982
983 return bad_expr_type(expr);
984 }
985
986 static struct symbol *evaluate_comma(struct expression *expr)
987 {
988 expr->ctype = degenerate(expr->right);
989 if (expr->ctype == &null_ctype)
990 expr->ctype = &ptr_ctype;
991 expr->flags &= expr->left->flags & expr->right->flags;
992 return expr->ctype;
993 }
994
995 static int modify_for_unsigned(int op)
996 {
997 if (op == '<')
998 op = SPECIAL_UNSIGNED_LT;
999 else if (op == '>')
1000 op = SPECIAL_UNSIGNED_GT;
1001 else if (op == SPECIAL_LTE)
1002 op = SPECIAL_UNSIGNED_LTE;
1003 else if (op == SPECIAL_GTE)
1004 op = SPECIAL_UNSIGNED_GTE;
1005 return op;
1006 }
1007
1008 static inline int is_null_pointer_constant(struct expression *e)
1009 {
1010 if (e->ctype == &null_ctype)
1011 return 1;
1012 if (!(e->flags & CEF_ICE))
1013 return 0;
1014 return is_zero_constant(e) ? 2 : 0;
1015 }
1016
1017 static struct symbol *evaluate_compare(struct expression *expr)
1018 {
1019 struct expression *left = expr->left, *right = expr->right;
1020 struct symbol *ltype, *rtype, *lbase, *rbase;
1021 int lclass = classify_type(degenerate(left), <ype);
1022 int rclass = classify_type(degenerate(right), &rtype);
1023 struct symbol *ctype;
1024 const char *typediff;
1025
1026 /* Type types? */
1027 if (is_type_type(ltype) && is_type_type(rtype)) {
1028 /*
1029 * __builtin_types_compatible_p() yields an integer
1030 * constant expression
1031 */
1032 expr->flags = CEF_SET_ICE;
1033 goto OK;
1034 }
1035
1036 if (is_safe_type(left->ctype) || is_safe_type(right->ctype))
1037 warning(expr->pos, "testing a 'safe expression'");
1038
1039 expr->flags = left->flags & right->flags & ~CEF_CONST_MASK & ~CEF_ADDR;
1040
1041 /* number on number */
1042 if (lclass & rclass & TYPE_NUM) {
1043 ctype = usual_conversions(expr->op, expr->left, expr->right,
1044 lclass, rclass, ltype, rtype);
1045 expr->left = cast_to(expr->left, ctype);
1046 expr->right = cast_to(expr->right, ctype);
1047 if (ctype->ctype.modifiers & MOD_UNSIGNED)
1048 expr->op = modify_for_unsigned(expr->op);
1049 goto OK;
1050 }
1051
1052 /* at least one must be a pointer */
1053 if (!((lclass | rclass) & TYPE_PTR))
1054 return bad_expr_type(expr);
1055
1056 /* equality comparisons can be with null pointer constants */
1057 if (expr->op == SPECIAL_EQUAL || expr->op == SPECIAL_NOTEQUAL) {
1058 int is_null1 = is_null_pointer_constant(left);
1059 int is_null2 = is_null_pointer_constant(right);
1060 if (is_null1 == 2)
1061 bad_null(left);
1062 if (is_null2 == 2)
1063 bad_null(right);
1064 if (is_null1 && is_null2) {
1065 int positive = expr->op == SPECIAL_EQUAL;
1066 expr->type = EXPR_VALUE;
1067 expr->value = positive;
1068 goto OK;
1069 }
1070 if (is_null1 && (rclass & TYPE_PTR)) {
1071 left = cast_to(left, rtype);
1072 goto OK;
1073 }
1074 if (is_null2 && (lclass & TYPE_PTR)) {
1075 right = cast_to(right, ltype);
1076 goto OK;
1077 }
1078 }
1079 /* both should be pointers */
1080 if (!(lclass & rclass & TYPE_PTR))
1081 return bad_expr_type(expr);
1082 expr->op = modify_for_unsigned(expr->op);
1083
1084 lbase = examine_pointer_target(ltype);
1085 rbase = examine_pointer_target(rtype);
1086
1087 /* they also have special treatment for pointers to void */
1088 if (expr->op == SPECIAL_EQUAL || expr->op == SPECIAL_NOTEQUAL) {
1089 if (ltype->ctype.as == rtype->ctype.as) {
1090 if (lbase == &void_ctype) {
1091 right = cast_to(right, ltype);
1092 goto OK;
1093 }
1094 if (rbase == &void_ctype) {
1095 left = cast_to(left, rtype);
1096 goto OK;
1097 }
1098 }
1099 }
1100
1101 typediff = type_difference(<ype->ctype, &rtype->ctype,
1102 target_qualifiers(rtype),
1103 target_qualifiers(ltype));
1104 if (!typediff)
1105 goto OK;
1106
1107 expression_error(expr, "incompatible types in comparison expression (%s)", typediff);
1108 return NULL;
1109
1110 OK:
1111 /* the result is int [6.5.8(6), 6.5.9(3)]*/
1112 expr->ctype = &int_ctype;
1113 return &int_ctype;
1114 }
1115
1116 /*
1117 * NOTE! The degenerate case of "x ? : y", where we don't
1118 * have a true case, this will possibly promote "x" to the
1119 * same type as "y", and thus _change_ the conditional
1120 * test in the expression. But since promotion is "safe"
1121 * for testing, that's OK.
1122 */
1123 static struct symbol *evaluate_conditional_expression(struct expression *expr)
1124 {
1125 struct expression **true;
1126 struct symbol *ctype, *ltype, *rtype, *lbase, *rbase;
1127 int lclass, rclass;
1128 const char * typediff;
1129 int qual;
1130
1131 if (!evaluate_conditional(expr->conditional, 0))
1132 return NULL;
1133 if (!evaluate_expression(expr->cond_false))
1134 return NULL;
1135
1136 ctype = degenerate(expr->conditional);
1137 rtype = degenerate(expr->cond_false);
1138
1139 true = &expr->conditional;
1140 ltype = ctype;
1141 if (expr->cond_true) {
1142 if (!evaluate_expression(expr->cond_true))
1143 return NULL;
1144 ltype = degenerate(expr->cond_true);
1145 true = &expr->cond_true;
1146 }
1147
1148 expr->flags = (expr->conditional->flags & (*true)->flags &
1149 expr->cond_false->flags & ~CEF_CONST_MASK);
1150 /*
1151 * A conditional operator yields a particular constant
1152 * expression type only if all of its three subexpressions are
1153 * of that type [6.6(6), 6.6(8)].
1154 * As an extension, relax this restriction by allowing any
1155 * constant expression type for the condition expression.
1156 *
1157 * A conditional operator never yields an address constant
1158 * [6.6(9)].
1159 * However, as an extension, if the condition is any constant
1160 * expression, and the true and false expressions are both
1161 * address constants, mark the result as an address constant.
1162 */
1163 if (expr->conditional->flags & (CEF_ACE | CEF_ADDR))
1164 expr->flags = (*true)->flags & expr->cond_false->flags & ~CEF_CONST_MASK;
1165
1166 lclass = classify_type(ltype, <ype);
1167 rclass = classify_type(rtype, &rtype);
1168 if (lclass & rclass & TYPE_NUM) {
1169 ctype = usual_conversions('?', *true, expr->cond_false,
1170 lclass, rclass, ltype, rtype);
1171 *true = cast_to(*true, ctype);
1172 expr->cond_false = cast_to(expr->cond_false, ctype);
1173 goto out;
1174 }
1175
1176 if ((lclass | rclass) & TYPE_PTR) {
1177 int is_null1 = is_null_pointer_constant(*true);
1178 int is_null2 = is_null_pointer_constant(expr->cond_false);
1179
1180 if (is_null1 && is_null2) {
1181 *true = cast_to(*true, &ptr_ctype);
1182 expr->cond_false = cast_to(expr->cond_false, &ptr_ctype);
1183 ctype = &ptr_ctype;
1184 goto out;
1185 }
1186 if (is_null1 && (rclass & TYPE_PTR)) {
1187 if (is_null1 == 2)
1188 bad_null(*true);
1189 *true = cast_to(*true, rtype);
1190 ctype = rtype;
1191 goto out;
1192 }
1193 if (is_null2 && (lclass & TYPE_PTR)) {
1194 if (is_null2 == 2)
1195 bad_null(expr->cond_false);
1196 expr->cond_false = cast_to(expr->cond_false, ltype);
1197 ctype = ltype;
1198 goto out;
1199 }
1200 if (!(lclass & rclass & TYPE_PTR)) {
1201 typediff = "different types";
1202 goto Err;
1203 }
1204 /* OK, it's pointer on pointer */
1205 if (ltype->ctype.as != rtype->ctype.as) {
1206 typediff = "different address spaces";
1207 goto Err;
1208 }
1209
1210 /* need to be lazier here */
1211 lbase = examine_pointer_target(ltype);
1212 rbase = examine_pointer_target(rtype);
1213 qual = target_qualifiers(ltype) | target_qualifiers(rtype);
1214
1215 if (lbase == &void_ctype) {
1216 /* XXX: pointers to function should warn here */
1217 ctype = ltype;
1218 goto Qual;
1219
1220 }
1221 if (rbase == &void_ctype) {
1222 /* XXX: pointers to function should warn here */
1223 ctype = rtype;
1224 goto Qual;
1225 }
1226 /* XXX: that should be pointer to composite */
1227 ctype = ltype;
1228 typediff = type_difference(<ype->ctype, &rtype->ctype,
1229 qual, qual);
1230 if (!typediff)
1231 goto Qual;
1232 goto Err;
1233 }
1234
1235 /* void on void, struct on same struct, union on same union */
1236 if (ltype == rtype) {
1237 ctype = ltype;
1238 goto out;
1239 }
1240 typediff = "different base types";
1241
1242 Err:
1243 expression_error(expr, "incompatible types in conditional expression (%s)", typediff);
1244 /*
1245 * if the condition is constant, the type is in fact known
1246 * so use it, as gcc & clang do.
1247 */
1248 switch (expr_truth_value(expr->conditional)) {
1249 case 1: expr->ctype = ltype;
1250 break;
1251 case 0: expr->ctype = rtype;
1252 break;
1253 default:
1254 break;
1255 }
1256 return NULL;
1257
1258 out:
1259 expr->ctype = ctype;
1260 return ctype;
1261
1262 Qual:
1263 if (qual & ~ctype->ctype.modifiers) {
1264 struct symbol *sym = alloc_symbol(ctype->pos, SYM_PTR);
1265 *sym = *ctype;
1266 sym->ctype.modifiers |= qual;
1267 ctype = sym;
1268 }
1269 *true = cast_to(*true, ctype);
1270 expr->cond_false = cast_to(expr->cond_false, ctype);
1271 goto out;
1272 }
1273
1274 /* FP assignments can not do modulo or bit operations */
1275 static int compatible_float_op(int op)
1276 {
1277 return op == SPECIAL_ADD_ASSIGN ||
1278 op == SPECIAL_SUB_ASSIGN ||
1279 op == SPECIAL_MUL_ASSIGN ||
1280 op == SPECIAL_DIV_ASSIGN;
1281 }
1282
1283 static int evaluate_assign_op(struct expression *expr)
1284 {
1285 struct symbol *target = expr->left->ctype;
1286 struct symbol *source = expr->right->ctype;
1287 struct symbol *t, *s;
1288 int tclass = classify_type(target, &t);
1289 int sclass = classify_type(source, &s);
1290 int op = expr->op;
1291
1292 if (tclass & sclass & TYPE_NUM) {
1293 if (tclass & TYPE_FLOAT && !compatible_float_op(op)) {
1294 expression_error(expr, "invalid assignment");
1295 return 0;
1296 }
1297 if (tclass & TYPE_RESTRICT) {
1298 if (!restricted_binop(op, t)) {
1299 warning(expr->pos, "bad assignment (%s) to %s",
1300 show_special(op), show_typename(t));
1301 expr->right = cast_to(expr->right, target);
1302 return 0;
1303 }
1304 /* allowed assignments unfoul */
1305 if (sclass & TYPE_FOULED && unfoul(s) == t)
1306 goto Cast;
1307 if (!restricted_value(expr->right, t))
1308 return 1;
1309 } else if (!(sclass & TYPE_RESTRICT))
1310 goto usual;
1311 /* source and target would better be identical restricted */
1312 if (t == s)
1313 return 1;
1314 warning(expr->pos, "invalid assignment: %s", show_special(op));
1315 info(expr->pos, " left side has type %s", show_typename(t));
1316 info(expr->pos, " right side has type %s", show_typename(s));
1317 expr->right = cast_to(expr->right, target);
1318 return 0;
1319 }
1320 if (tclass == TYPE_PTR && is_int(sclass)) {
1321 if (op == SPECIAL_ADD_ASSIGN || op == SPECIAL_SUB_ASSIGN) {
1322 unrestrict(expr->right, sclass, &s);
1323 evaluate_ptr_add(expr, s);
1324 return 1;
1325 }
1326 expression_error(expr, "invalid pointer assignment");
1327 return 0;
1328 }
1329
1330 expression_error(expr, "invalid assignment");
1331 return 0;
1332
1333 usual:
1334 target = usual_conversions(op, expr->left, expr->right,
1335 tclass, sclass, target, source);
1336 Cast:
1337 expr->right = cast_to(expr->right, target);
1338 return 1;
1339 }
1340
1341 static int whitelist_pointers(struct symbol *t1, struct symbol *t2)
1342 {
1343 if (t1 == t2)
1344 return 0; /* yes, 0 - we don't want a cast_to here */
1345 if (t1 == &void_ctype)
1346 return 1;
1347 if (t2 == &void_ctype)
1348 return 1;
1349 if (classify_type(t1, &t1) != TYPE_NUM)
1350 return 0;
1351 if (classify_type(t2, &t2) != TYPE_NUM)
1352 return 0;
1353 if (t1 == t2)
1354 return 1;
1355 if (t1->ctype.modifiers & t2->ctype.modifiers & MOD_CHAR)
1356 return 1;
1357 if ((t1->ctype.modifiers ^ t2->ctype.modifiers) & MOD_SIZE)
1358 return 0;
1359 return !Wtypesign;
1360 }
1361
1362 static int check_assignment_types(struct symbol *target, struct expression **rp,
1363 const char **typediff)
1364 {
1365 struct symbol *source = degenerate(*rp);
1366 struct symbol *t, *s;
1367 int tclass = classify_type(target, &t);
1368 int sclass = classify_type(source, &s);
1369
1370 if (tclass & sclass & TYPE_NUM) {
1371 if (tclass & TYPE_RESTRICT) {
1372 /* allowed assignments unfoul */
1373 if (sclass & TYPE_FOULED && unfoul(s) == t)
1374 goto Cast;
1375 if (!restricted_value(*rp, target))
1376 return 1;
1377 if (s == t)
1378 return 1;
1379 } else if (!(sclass & TYPE_RESTRICT))
1380 goto Cast;
1381 if (t == &bool_ctype) {
1382 if (is_fouled_type(s))
1383 warning((*rp)->pos, "%s degrades to integer",
1384 show_typename(s->ctype.base_type));
1385 goto Cast;
1386 }
1387 *typediff = "different base types";
1388 return 0;
1389 }
1390
1391 if (tclass == TYPE_PTR) {
1392 unsigned long mod1, mod2;
1393 struct symbol *b1, *b2;
1394 // NULL pointer is always OK
1395 int is_null = is_null_pointer_constant(*rp);
1396 if (is_null) {
1397 if (is_null == 2)
1398 bad_null(*rp);
1399 goto Cast;
1400 }
1401 if (!(sclass & TYPE_PTR)) {
1402 *typediff = "different base types";
1403 return 0;
1404 }
1405 b1 = examine_pointer_target(t);
1406 b2 = examine_pointer_target(s);
1407 mod1 = target_qualifiers(t);
1408 mod2 = target_qualifiers(s);
1409 if (whitelist_pointers(b1, b2)) {
1410 /*
1411 * assignments to/from void * are OK, provided that
1412 * we do not remove qualifiers from pointed to [C]
1413 * or mix address spaces [sparse].
1414 */
1415 if (t->ctype.as != s->ctype.as) {
1416 *typediff = "different address spaces";
1417 return 0;
1418 }
1419 /*
1420 * If this is a function pointer assignment, it is
1421 * actually fine to assign a pointer to const data to
1422 * it, as a function pointer points to const data
1423 * implicitly, i.e., dereferencing it does not produce
1424 * an lvalue.
1425 */
1426 if (b1->type == SYM_FN)
1427 mod1 |= MOD_CONST;
1428 if (mod2 & ~mod1) {
1429 *typediff = "different modifiers";
1430 return 0;
1431 }
1432 goto Cast;
1433 }
1434 /* It's OK if the target is more volatile or const than the source */
1435 *typediff = type_difference(&t->ctype, &s->ctype, 0, mod1);
1436 if (*typediff)
1437 return 0;
1438 return 1;
1439 }
1440
1441 if ((tclass & TYPE_COMPOUND) && s == t)
1442 return 1;
1443
1444 if (tclass & TYPE_NUM) {
1445 /* XXX: need to turn into comparison with NULL */
1446 if (t == &bool_ctype && (sclass & TYPE_PTR))
1447 goto Cast;
1448 *typediff = "different base types";
1449 return 0;
1450 }
1451 *typediff = "invalid types";
1452 return 0;
1453
1454 Cast:
1455 *rp = cast_to(*rp, target);
1456 return 1;
1457 }
1458
1459 static int compatible_assignment_types(struct expression *expr, struct symbol *target,
1460 struct expression **rp, const char *where)
1461 {
1462 const char *typediff;
1463 struct symbol *source = degenerate(*rp);
1464
1465 if (!check_assignment_types(target, rp, &typediff)) {
1466 warning(expr->pos, "incorrect type in %s (%s)", where, typediff);
1467 info(expr->pos, " expected %s", show_typename(target));
1468 info(expr->pos, " got %s", show_typename(source));
1469 *rp = cast_to(*rp, target);
1470 return 0;
1471 }
1472
1473 return 1;
1474 }
1475
1476 static int compatible_transparent_union(struct symbol *target,
1477 struct expression **rp)
1478 {
1479 struct symbol *t, *member;
1480 classify_type(target, &t);
1481 if (t->type != SYM_UNION || !t->transparent_union)
1482 return 0;
1483
1484 FOR_EACH_PTR(t->symbol_list, member) {
1485 const char *typediff;
1486 if (check_assignment_types(member, rp, &typediff))
1487 return 1;
1488 } END_FOR_EACH_PTR(member);
1489
1490 return 0;
1491 }
1492
1493 static int compatible_argument_type(struct expression *expr, struct symbol *target,
1494 struct expression **rp, const char *where)
1495 {
1496 if (compatible_transparent_union(target, rp))
1497 return 1;
1498
1499 return compatible_assignment_types(expr, target, rp, where);
1500 }
1501
1502 static void mark_assigned(struct expression *expr)
1503 {
1504 struct symbol *sym;
1505
1506 if (!expr)
1507 return;
1508 switch (expr->type) {
1509 case EXPR_SYMBOL:
1510 sym = expr->symbol;
1511 if (!sym)
1512 return;
1513 if (sym->type != SYM_NODE)
1514 return;
1515 sym->ctype.modifiers |= MOD_ASSIGNED;
1516 return;
1517
1518 case EXPR_BINOP:
1519 mark_assigned(expr->left);
1520 mark_assigned(expr->right);
1521 return;
1522 case EXPR_CAST:
1523 case EXPR_FORCE_CAST:
1524 mark_assigned(expr->cast_expression);
1525 return;
1526 case EXPR_SLICE:
1527 mark_assigned(expr->base);
1528 return;
1529 default:
1530 /* Hmm? */
1531 return;
1532 }
1533 }
1534
1535 static void evaluate_assign_to(struct expression *left, struct symbol *type)
1536 {
1537 if (type->ctype.modifiers & MOD_CONST)
1538 expression_error(left, "assignment to const expression");
1539
1540 /* We know left is an lvalue, so it's a "preop-*" */
1541 mark_assigned(left->unop);
1542 }
1543
1544 static struct symbol *evaluate_assignment(struct expression *expr)
1545 {
1546 struct expression *left = expr->left;
1547 struct expression *where = expr;
1548 struct symbol *ltype;
1549
1550 if (!lvalue_expression(left)) {
1551 expression_error(expr, "not an lvalue");
1552 return NULL;
1553 }
1554
1555 ltype = left->ctype;
1556
1557 if (expr->op != '=') {
1558 if (!evaluate_assign_op(expr))
1559 return NULL;
1560 } else {
1561 if (!compatible_assignment_types(where, ltype, &expr->right, "assignment"))
1562 return NULL;
1563 }
1564
1565 evaluate_assign_to(left, ltype);
1566
1567 expr->ctype = ltype;
1568 return ltype;
1569 }
1570
1571 static void examine_fn_arguments(struct symbol *fn)
1572 {
1573 struct symbol *s;
1574
1575 FOR_EACH_PTR(fn->arguments, s) {
1576 struct symbol *arg = evaluate_symbol(s);
1577 /* Array/function arguments silently degenerate into pointers */
1578 if (arg) {
1579 struct symbol *ptr;
1580 switch(arg->type) {
1581 case SYM_ARRAY:
1582 case SYM_FN:
1583 ptr = alloc_symbol(s->pos, SYM_PTR);
1584 if (arg->type == SYM_ARRAY)
1585 ptr->ctype = arg->ctype;
1586 else
1587 ptr->ctype.base_type = arg;
1588 ptr->ctype.as |= s->ctype.as;
1589 ptr->ctype.modifiers |= s->ctype.modifiers & MOD_PTRINHERIT;
1590
1591 s->ctype.base_type = ptr;
1592 s->ctype.as = 0;
1593 s->ctype.modifiers &= ~MOD_PTRINHERIT;
1594 s->bit_size = 0;
1595 s->examined = 0;
1596 examine_symbol_type(s);
1597 break;
1598 default:
1599 /* nothing */
1600 break;
1601 }
1602 }
1603 } END_FOR_EACH_PTR(s);
1604 }
1605
1606 static struct symbol *convert_to_as_mod(struct symbol *sym, int as, int mod)
1607 {
1608 /* Take the modifiers of the pointer, and apply them to the member */
1609 mod |= sym->ctype.modifiers;
1610 if (sym->ctype.as != as || sym->ctype.modifiers != mod) {
1611 struct symbol *newsym = alloc_symbol(sym->pos, SYM_NODE);
1612 *newsym = *sym;
1613 newsym->ctype.as = as;
1614 newsym->ctype.modifiers = mod;
1615 sym = newsym;
1616 }
1617 return sym;
1618 }
1619
1620 static struct symbol *create_pointer(struct expression *expr, struct symbol *sym, int degenerate)
1621 {
1622 struct symbol *node = alloc_symbol(expr->pos, SYM_NODE);
1623 struct symbol *ptr = alloc_symbol(expr->pos, SYM_PTR);
1624
1625 node->ctype.base_type = ptr;
1626 ptr->bit_size = bits_in_pointer;
1627 ptr->ctype.alignment = pointer_alignment;
1628
1629 node->bit_size = bits_in_pointer;
1630 node->ctype.alignment = pointer_alignment;
1631
1632 access_symbol(sym);
1633 if (sym->ctype.modifiers & MOD_REGISTER) {
1634 warning(expr->pos, "taking address of 'register' variable '%s'", show_ident(sym->ident));
1635 sym->ctype.modifiers &= ~MOD_REGISTER;
1636 }
1637 if (sym->type == SYM_NODE) {
1638 ptr->ctype.as |= sym->ctype.as;
1639 ptr->ctype.modifiers |= sym->ctype.modifiers & MOD_PTRINHERIT;
1640 sym = sym->ctype.base_type;
1641 }
1642 if (degenerate && sym->type == SYM_ARRAY) {
1643 ptr->ctype.as |= sym->ctype.as;
1644 ptr->ctype.modifiers |= sym->ctype.modifiers & MOD_PTRINHERIT;
1645 sym = sym->ctype.base_type;
1646 }
1647 ptr->ctype.base_type = sym;
1648
1649 return node;
1650 }
1651
1652 /* Arrays degenerate into pointers on pointer arithmetic */
1653 static struct symbol *degenerate(struct expression *expr)
1654 {
1655 struct symbol *ctype, *base;
1656
1657 if (!expr)
1658 return NULL;
1659 ctype = expr->ctype;
1660 if (!ctype)
1661 return NULL;
1662 base = examine_symbol_type(ctype);
1663 if (ctype->type == SYM_NODE)
1664 base = ctype->ctype.base_type;
1665 /*
1666 * Arrays degenerate into pointers to the entries, while
1667 * functions degenerate into pointers to themselves.
1668 * If array was part of non-lvalue compound, we create a copy
1669 * of that compound first and then act as if we were dealing with
1670 * the corresponding field in there.
1671 */
1672 switch (base->type) {
1673 case SYM_ARRAY:
1674 if (expr->type == EXPR_SLICE) {
1675 struct symbol *a = alloc_symbol(expr->pos, SYM_NODE);
1676 struct expression *e0, *e1, *e2, *e3, *e4;
1677
1678 a->ctype.base_type = expr->base->ctype;
1679 a->bit_size = expr->base->ctype->bit_size;
1680 a->array_size = expr->base->ctype->array_size;
1681
1682 e0 = alloc_expression(expr->pos, EXPR_SYMBOL);
1683 e0->symbol = a;
1684 e0->ctype = &lazy_ptr_ctype;
1685
1686 e1 = alloc_expression(expr->pos, EXPR_PREOP);
1687 e1->unop = e0;
1688 e1->op = '*';
1689 e1->ctype = expr->base->ctype; /* XXX */
1690
1691 e2 = alloc_expression(expr->pos, EXPR_ASSIGNMENT);
1692 e2->left = e1;
1693 e2->right = expr->base;
1694 e2->op = '=';
1695 e2->ctype = expr->base->ctype;
1696
1697 if (expr->r_bitpos) {
1698 e3 = alloc_expression(expr->pos, EXPR_BINOP);
1699 e3->op = '+';
1700 e3->left = e0;
1701 e3->right = alloc_const_expression(expr->pos,
1702 bits_to_bytes(expr->r_bitpos));
1703 e3->ctype = &lazy_ptr_ctype;
1704 } else {
1705 e3 = e0;
1706 }
1707
1708 e4 = alloc_expression(expr->pos, EXPR_COMMA);
1709 e4->left = e2;
1710 e4->right = e3;
1711 e4->ctype = &lazy_ptr_ctype;
1712
1713 expr->unop = e4;
1714 expr->type = EXPR_PREOP;
1715 expr->op = '*';
1716 }
1717 case SYM_FN:
1718 if (expr->op != '*' || expr->type != EXPR_PREOP) {
1719 expression_error(expr, "strange non-value function or array");
1720 return &bad_ctype;
1721 }
1722 *expr = *expr->unop;
1723 ctype = create_pointer(expr, ctype, 1);
1724 expr->ctype = ctype;
1725 default:
1726 /* nothing */;
1727 }
1728 return ctype;
1729 }
1730
1731 static struct symbol *evaluate_addressof(struct expression *expr)
1732 {
1733 struct expression *op = expr->unop;
1734 struct symbol *ctype;
1735
1736 if (op->op != '*' || op->type != EXPR_PREOP) {
1737 expression_error(expr, "not addressable");
1738 return NULL;
1739 }
1740 ctype = op->ctype;
1741 *expr = *op->unop;
1742
1743 if (expr->type == EXPR_SYMBOL) {
1744 struct symbol *sym = expr->symbol;
1745 sym->ctype.modifiers |= MOD_ADDRESSABLE;
1746 }
1747
1748 /*
1749 * symbol expression evaluation is lazy about the type
1750 * of the sub-expression, so we may have to generate
1751 * the type here if so..
1752 */
1753 if (expr->ctype == &lazy_ptr_ctype) {
1754 ctype = create_pointer(expr, ctype, 0);
1755 expr->ctype = ctype;
1756 }
1757 return expr->ctype;
1758 }
1759
1760
1761 static struct symbol *evaluate_dereference(struct expression *expr)
1762 {
1763 struct expression *op = expr->unop;
1764 struct symbol *ctype = op->ctype, *node, *target;
1765
1766 /* Simplify: *&(expr) => (expr) */
1767 if (op->type == EXPR_PREOP && op->op == '&') {
1768 *expr = *op->unop;
1769 expr->flags = CEF_NONE;
1770 return expr->ctype;
1771 }
1772
1773 examine_symbol_type(ctype);
1774
1775 /* Dereferencing a node drops all the node information. */
1776 if (ctype->type == SYM_NODE)
1777 ctype = ctype->ctype.base_type;
1778
1779 node = alloc_symbol(expr->pos, SYM_NODE);
1780 target = ctype->ctype.base_type;
1781
1782 switch (ctype->type) {
1783 default:
1784 expression_error(expr, "cannot dereference this type");
1785 return NULL;
1786 case SYM_PTR:
1787 node->ctype.modifiers = target->ctype.modifiers & MOD_SPECIFIER;
1788 merge_type(node, ctype);
1789 break;
1790
1791 case SYM_ARRAY:
1792 if (!lvalue_expression(op)) {
1793 expression_error(op, "non-lvalue array??");
1794 return NULL;
1795 }
1796
1797 /* Do the implied "addressof" on the array */
1798 *op = *op->unop;
1799
1800 /*
1801 * When an array is dereferenced, we need to pick
1802 * up the attributes of the original node too..
1803 */
1804 merge_type(node, op->ctype);
1805 merge_type(node, ctype);
1806 break;
1807 }
1808
1809 node->bit_size = target->bit_size;
1810 node->array_size = target->array_size;
1811
1812 expr->ctype = node;
1813 return node;
1814 }
1815
1816 /*
1817 * Unary post-ops: x++ and x--
1818 */
1819 static struct symbol *evaluate_postop(struct expression *expr)
1820 {
1821 struct expression *op = expr->unop;
1822 struct symbol *ctype = op->ctype;
1823 int class = classify_type(ctype, &ctype);
1824 int multiply = 0;
1825
1826 if (!class || class & TYPE_COMPOUND) {
1827 expression_error(expr, "need scalar for ++/--");
1828 return NULL;
1829 }
1830 if (!lvalue_expression(expr->unop)) {
1831 expression_error(expr, "need lvalue expression for ++/--");
1832 return NULL;
1833 }
1834
1835 if ((class & TYPE_RESTRICT) && restricted_unop(expr->op, &ctype))
1836 unrestrict(expr, class, &ctype);
1837
1838 if (class & TYPE_NUM) {
1839 multiply = 1;
1840 } else if (class == TYPE_PTR) {
1841 struct symbol *target = examine_pointer_target(ctype);
1842 if (!is_function(target))
1843 multiply = bits_to_bytes(target->bit_size);
1844 }
1845
1846 if (multiply) {
1847 evaluate_assign_to(op, op->ctype);
1848 expr->op_value = multiply;
1849 expr->ctype = ctype;
1850 return ctype;
1851 }
1852
1853 expression_error(expr, "bad argument type for ++/--");
1854 return NULL;
1855 }
1856
1857 static struct symbol *evaluate_sign(struct expression *expr)
1858 {
1859 struct symbol *ctype = expr->unop->ctype;
1860 int class = classify_type(ctype, &ctype);
1861 unsigned char flags = expr->unop->flags & ~CEF_CONST_MASK;
1862
1863 /* should be an arithmetic type */
1864 if (!(class & TYPE_NUM))
1865 return bad_expr_type(expr);
1866 if (class & TYPE_RESTRICT)
1867 goto Restr;
1868 Normal:
1869 if (!(class & TYPE_FLOAT)) {
1870 ctype = integer_promotion(ctype);
1871 expr->unop = cast_to(expr->unop, ctype);
1872 } else if (expr->op != '~') {
1873 /* no conversions needed */
1874 } else {
1875 return bad_expr_type(expr);
1876 }
1877 if (expr->op == '+')
1878 *expr = *expr->unop;
1879 expr->flags = flags;
1880 expr->ctype = ctype;
1881 return ctype;
1882 Restr:
1883 if (restricted_unop(expr->op, &ctype))
1884 unrestrict(expr, class, &ctype);
1885 goto Normal;
1886 }
1887
1888 static struct symbol *evaluate_preop(struct expression *expr)
1889 {
1890 struct symbol *ctype = expr->unop->ctype;
1891
1892 switch (expr->op) {
1893 case '(':
1894 *expr = *expr->unop;
1895 return ctype;
1896
1897 case '+':
1898 case '-':
1899 case '~':
1900 return evaluate_sign(expr);
1901
1902 case '*':
1903 return evaluate_dereference(expr);
1904
1905 case '&':
1906 return evaluate_addressof(expr);
1907
1908 case SPECIAL_INCREMENT:
1909 case SPECIAL_DECREMENT:
1910 /*
1911 * From a type evaluation standpoint the preops are
1912 * the same as the postops
1913 */
1914 return evaluate_postop(expr);
1915
1916 case '!':
1917 expr->flags = expr->unop->flags & ~CEF_CONST_MASK;
1918 /*
1919 * A logical negation never yields an address constant
1920 * [6.6(9)].
1921 */
1922 expr->flags &= ~CEF_ADDR;
1923
1924 if (is_safe_type(ctype))
1925 warning(expr->pos, "testing a 'safe expression'");
1926 if (is_float_type(ctype)) {
1927 struct expression *arg = expr->unop;
1928 expr->type = EXPR_COMPARE;
1929 expr->op = SPECIAL_EQUAL;
1930 expr->left = arg;
1931 expr->right = alloc_expression(expr->pos, EXPR_FVALUE);
1932 expr->right->ctype = ctype;
1933 expr->right->fvalue = 0;
1934 } else if (is_fouled_type(ctype)) {
1935 warning(expr->pos, "%s degrades to integer",
1936 show_typename(ctype->ctype.base_type));
1937 }
1938 /* the result is int [6.5.3.3(5)]*/
1939 ctype = &int_ctype;
1940 break;
1941
1942 default:
1943 break;
1944 }
1945 expr->ctype = ctype;
1946 return ctype;
1947 }
1948
1949 struct symbol *find_identifier(struct ident *ident, struct symbol_list *_list, int *offset)
1950 {
1951 struct ptr_list *head = (struct ptr_list *)_list;
1952 struct ptr_list *list = head;
1953
1954 if (!head)
1955 return NULL;
1956 do {
1957 int i;
1958 for (i = 0; i < list->nr; i++) {
1959 struct symbol *sym = (struct symbol *) list->list[i];
1960 if (sym->ident) {
1961 if (sym->ident != ident)
1962 continue;
1963 *offset = sym->offset;
1964 return sym;
1965 } else {
1966 struct symbol *ctype = sym->ctype.base_type;
1967 struct symbol *sub;
1968 if (!ctype)
1969 continue;
1970 if (ctype->type != SYM_UNION && ctype->type != SYM_STRUCT)
1971 continue;
1972 sub = find_identifier(ident, ctype->symbol_list, offset);
1973 if (!sub)
1974 continue;
1975 *offset += sym->offset;
1976 return sub;
1977 }
1978 }
1979 } while ((list = list->next) != head);
1980 return NULL;
1981 }
1982
1983 static struct expression *evaluate_offset(struct expression *expr, unsigned long offset)
1984 {
1985 struct expression *add;
1986
1987 /*
1988 * Create a new add-expression
1989 *
1990 * NOTE! Even if we just add zero, we need a new node
1991 * for the member pointer, since it has a different
1992 * type than the original pointer. We could make that
1993 * be just a cast, but the fact is, a node is a node,
1994 * so we might as well just do the "add zero" here.
1995 */
1996 add = alloc_expression(expr->pos, EXPR_BINOP);
1997 add->op = '+';
1998 add->left = expr;
1999 add->right = alloc_expression(expr->pos, EXPR_VALUE);
2000 add->right->ctype = &int_ctype;
2001 add->right->value = offset;
2002
2003 /*
2004 * The ctype of the pointer will be lazily evaluated if
2005 * we ever take the address of this member dereference..
2006 */
2007 add->ctype = &lazy_ptr_ctype;
2008 /*
2009 * The resulting address of a member access through an address
2010 * constant is an address constant again [6.6(9)].
2011 */
2012 add->flags = expr->flags;
2013
2014 return add;
2015 }
2016
2017 /* structure/union dereference */
2018 static struct symbol *evaluate_member_dereference(struct expression *expr)
2019 {
2020 int offset;
2021 struct symbol *ctype, *member;
2022 struct expression *deref = expr->deref, *add;
2023 struct ident *ident = expr->member;
2024 unsigned int mod;
2025 int address_space;
2026
2027 if (!evaluate_expression(deref))
2028 return NULL;
2029 if (!ident) {
2030 expression_error(expr, "bad member name");
2031 return NULL;
2032 }
2033
2034 ctype = deref->ctype;
2035 examine_symbol_type(ctype);
2036 address_space = ctype->ctype.as;
2037 mod = ctype->ctype.modifiers;
2038 if (ctype->type == SYM_NODE) {
2039 ctype = ctype->ctype.base_type;
2040 address_space |= ctype->ctype.as;
2041 mod |= ctype->ctype.modifiers;
2042 }
2043 if (!ctype || (ctype->type != SYM_STRUCT && ctype->type != SYM_UNION)) {
2044 expression_error(expr, "expected structure or union");
2045 return NULL;
2046 }
2047 offset = 0;
2048 member = find_identifier(ident, ctype->symbol_list, &offset);
2049 if (!member) {
2050 const char *type = ctype->type == SYM_STRUCT ? "struct" : "union";
2051 const char *name = "<unnamed>";
2052 int namelen = 9;
2053 if (ctype->ident) {
2054 name = ctype->ident->name;
2055 namelen = ctype->ident->len;
2056 }
2057 if (ctype->symbol_list)
2058 expression_error(expr, "no member '%s' in %s %.*s",
2059 show_ident(ident), type, namelen, name);
2060 else
2061 expression_error(expr, "using member '%s' in "
2062 "incomplete %s %.*s", show_ident(ident),
2063 type, namelen, name);
2064 return NULL;
2065 }
2066
2067 /*
2068 * The member needs to take on the address space and modifiers of
2069 * the "parent" type.
2070 */
2071 member = convert_to_as_mod(member, address_space, mod);
2072 ctype = get_base_type(member);
2073
2074 if (!lvalue_expression(deref)) {
2075 if (deref->type != EXPR_SLICE) {
2076 expr->base = deref;
2077 expr->r_bitpos = 0;
2078 } else {
2079 expr->base = deref->base;
2080 expr->r_bitpos = deref->r_bitpos;
2081 }
2082 expr->r_bitpos += bytes_to_bits(offset);
2083 expr->type = EXPR_SLICE;
2084 expr->r_nrbits = member->bit_size;
2085 expr->r_bitpos += member->bit_offset;
2086 expr->ctype = member;
2087 return member;
2088 }
2089
2090 deref = deref->unop;
2091 expr->deref = deref;
2092
2093 add = evaluate_offset(deref, offset);
2094 expr->type = EXPR_PREOP;
2095 expr->op = '*';
2096 expr->unop = add;
2097
2098 expr->ctype = member;
2099 return member;
2100 }
2101
2102 static int is_promoted(struct expression *expr)
2103 {
2104 while (1) {
2105 switch (expr->type) {
2106 case EXPR_BINOP:
2107 case EXPR_SELECT:
2108 case EXPR_CONDITIONAL:
2109 return 1;
2110 case EXPR_COMMA:
2111 expr = expr->right;
2112 continue;
2113 case EXPR_PREOP:
2114 switch (expr->op) {
2115 case '(':
2116 expr = expr->unop;
2117 continue;
2118 case '+':
2119 case '-':
2120 case '~':
2121 return 1;
2122 default:
2123 return 0;
2124 }
2125 default:
2126 return 0;
2127 }
2128 }
2129 }
2130
2131
2132 static struct symbol *evaluate_cast(struct expression *);
2133
2134 static struct symbol *evaluate_type_information(struct expression *expr)
2135 {
2136 struct symbol *sym = expr->cast_type;
2137 if (!sym) {
2138 sym = evaluate_expression(expr->cast_expression);
2139 if (!sym)
2140 return NULL;
2141 /*
2142 * Expressions of restricted types will possibly get
2143 * promoted - check that here
2144 */
2145 if (is_restricted_type(sym)) {
2146 if (sym->bit_size < bits_in_int && is_promoted(expr))
2147 sym = &int_ctype;
2148 } else if (is_fouled_type(sym)) {
2149 sym = &int_ctype;
2150 }
2151 }
2152 examine_symbol_type(sym);
2153 if (is_bitfield_type(sym)) {
2154 expression_error(expr, "trying to examine bitfield type");
2155 return NULL;
2156 }
2157 return sym;
2158 }
2159
2160 static struct symbol *evaluate_sizeof(struct expression *expr)
2161 {
2162 struct symbol *type;
2163 int size;
2164
2165 type = evaluate_type_information(expr);
2166 if (!type)
2167 return NULL;
2168
2169 size = type->bit_size;
2170
2171 if (size < 0 && is_void_type(type)) {
2172 if (Wpointer_arith)
2173 warning(expr->pos, "expression using sizeof(void)");
2174 size = bits_in_char;
2175 }
2176
2177 if (size == 1 && is_bool_type(type)) {
2178 if (Wsizeof_bool)
2179 warning(expr->pos, "expression using sizeof bool");
2180 size = bits_in_char;
2181 }
2182
2183 if (is_function(type->ctype.base_type)) {
2184 if (Wpointer_arith)
2185 warning(expr->pos, "expression using sizeof on a function");
2186 size = bits_in_char;
2187 }
2188
2189 if ((size < 0) || (size & (bits_in_char - 1)))
2190 expression_error(expr, "cannot size expression");
2191
2192 expr->type = EXPR_VALUE;
2193 expr->value = bits_to_bytes(size);
2194 expr->taint = 0;
2195 expr->ctype = size_t_ctype;
2196 return size_t_ctype;
2197 }
2198
2199 static struct symbol *evaluate_ptrsizeof(struct expression *expr)
2200 {
2201 struct symbol *type;
2202 int size;
2203
2204 type = evaluate_type_information(expr);
2205 if (!type)
2206 return NULL;
2207
2208 if (type->type == SYM_NODE)
2209 type = type->ctype.base_type;
2210 if (!type)
2211 return NULL;
2212 switch (type->type) {
2213 case SYM_ARRAY:
2214 break;
2215 case SYM_PTR:
2216 type = get_base_type(type);
2217 if (type)
2218 break;
2219 default:
2220 expression_error(expr, "expected pointer expression");
2221 return NULL;
2222 }
2223 size = type->bit_size;
2224 if (size & (bits_in_char-1))
2225 size = 0;
2226 expr->type = EXPR_VALUE;
2227 expr->value = bits_to_bytes(size);
2228 expr->taint = 0;
2229 expr->ctype = size_t_ctype;
2230 return size_t_ctype;
2231 }
2232
2233 static struct symbol *evaluate_alignof(struct expression *expr)
2234 {
2235 struct symbol *type;
2236
2237 type = evaluate_type_information(expr);
2238 if (!type)
2239 return NULL;
2240
2241 expr->type = EXPR_VALUE;
2242 expr->value = type->ctype.alignment;
2243 expr->taint = 0;
2244 expr->ctype = size_t_ctype;
2245 return size_t_ctype;
2246 }
2247
2248 static int evaluate_arguments(struct symbol *fn, struct expression_list *head)
2249 {
2250 struct expression *expr;
2251 struct symbol_list *argument_types = fn->arguments;
2252 struct symbol *argtype;
2253 int i = 1;
2254
2255 PREPARE_PTR_LIST(argument_types, argtype);
2256 FOR_EACH_PTR (head, expr) {
2257 struct expression **p = THIS_ADDRESS(expr);
2258 struct symbol *ctype, *target;
2259 ctype = evaluate_expression(expr);
2260
2261 if (!ctype)
2262 return 0;
2263
2264 target = argtype;
2265 if (!target) {
2266 struct symbol *type;
2267 int class = classify_type(ctype, &type);
2268 if (is_int(class)) {
2269 *p = cast_to(expr, integer_promotion(type));
2270 } else if (class & TYPE_FLOAT) {
2271 unsigned long mod = type->ctype.modifiers;
2272 if (!(mod & (MOD_LONG_ALL)))
2273 *p = cast_to(expr, &double_ctype);
2274 } else if (class & TYPE_PTR) {
2275 if (expr->ctype == &null_ctype)
2276 *p = cast_to(expr, &ptr_ctype);
2277 else
2278 degenerate(expr);
2279 }
2280 } else if (!target->forced_arg){
2281 static char where[30];
2282 examine_symbol_type(target);
2283 sprintf(where, "argument %d", i);
2284 compatible_argument_type(expr, target, p, where);
2285 }
2286
2287 i++;
2288 NEXT_PTR_LIST(argtype);
2289 } END_FOR_EACH_PTR(expr);
2290 FINISH_PTR_LIST(argtype);
2291 return 1;
2292 }
2293
2294 static void convert_index(struct expression *e)
2295 {
2296 struct expression *child = e->idx_expression;
2297 unsigned from = e->idx_from;
2298 unsigned to = e->idx_to + 1;
2299 e->type = EXPR_POS;
2300 e->init_offset = from * bits_to_bytes(e->ctype->bit_size);
2301 e->init_nr = to - from;
2302 e->init_expr = child;
2303 }
2304
2305 static void convert_ident(struct expression *e)
2306 {
2307 struct expression *child = e->ident_expression;
2308 int offset = e->offset;
2309
2310 e->type = EXPR_POS;
2311 e->init_offset = offset;
2312 e->init_nr = 1;
2313 e->init_expr = child;
2314 }
2315
2316 static void convert_designators(struct expression *e)
2317 {
2318 while (e) {
2319 if (e->type == EXPR_INDEX)
2320 convert_index(e);
2321 else if (e->type == EXPR_IDENTIFIER)
2322 convert_ident(e);
2323 else
2324 break;
2325 e = e->init_expr;
2326 }
2327 }
2328
2329 static void excess(struct expression *e, const char *s)
2330 {
2331 warning(e->pos, "excessive elements in %s initializer", s);
2332 }
2333
2334 /*
2335 * implicit designator for the first element
2336 */
2337 static struct expression *first_subobject(struct symbol *ctype, int class,
2338 struct expression **v)
2339 {
2340 struct expression *e = *v, *new;
2341
2342 if (ctype->type == SYM_NODE)
2343 ctype = ctype->ctype.base_type;
2344
2345 if (class & TYPE_PTR) { /* array */
2346 if (!ctype->bit_size)
2347 return NULL;
2348 new = alloc_expression(e->pos, EXPR_INDEX);
2349 new->idx_expression = e;
2350 new->ctype = ctype->ctype.base_type;
2351 } else {
2352 struct symbol *field, *p;
2353 PREPARE_PTR_LIST(ctype->symbol_list, p);
2354 while (p && !p->ident && is_bitfield_type(p))
2355 NEXT_PTR_LIST(p);
2356 field = p;
2357 FINISH_PTR_LIST(p);
2358 if (!field)
2359 return NULL;
2360 new = alloc_expression(e->pos, EXPR_IDENTIFIER);
2361 new->ident_expression = e;
2362 new->field = new->ctype = field;
2363 new->offset = field->offset;
2364 }
2365 *v = new;
2366 return new;
2367 }
2368
2369 /*
2370 * sanity-check explicit designators; return the innermost one or NULL
2371 * in case of error. Assign types.
2372 */
2373 static struct expression *check_designators(struct expression *e,
2374 struct symbol *ctype)
2375 {
2376 struct expression *last = NULL;
2377 const char *err;
2378 while (1) {
2379 if (ctype->type == SYM_NODE)
2380 ctype = ctype->ctype.base_type;
2381 if (e->type == EXPR_INDEX) {
2382 struct symbol *type;
2383 if (ctype->type != SYM_ARRAY) {
2384 err = "array index in non-array";
2385 break;
2386 }
2387 type = ctype->ctype.base_type;
2388 if (ctype->bit_size >= 0 && type->bit_size >= 0) {
2389 unsigned offset = array_element_offset(type->bit_size, e->idx_to);
2390 if (offset >= ctype->bit_size) {
2391 err = "index out of bounds in";
2392 break;
2393 }
2394 }
2395 e->ctype = ctype = type;
2396 ctype = type;
2397 last = e;
2398 if (!e->idx_expression) {
2399 err = "invalid";
2400 break;
2401 }
2402 e = e->idx_expression;
2403 } else if (e->type == EXPR_IDENTIFIER) {
2404 int offset = 0;
2405 if (ctype->type != SYM_STRUCT && ctype->type != SYM_UNION) {
2406 err = "field name not in struct or union";
2407 break;
2408 }
2409 ctype = find_identifier(e->expr_ident, ctype->symbol_list, &offset);
2410 if (!ctype) {
2411 err = "unknown field name in";
2412 break;
2413 }
2414 e->offset = offset;
2415 e->field = e->ctype = ctype;
2416 last = e;
2417 if (!e->ident_expression) {
2418 err = "invalid";
2419 break;
2420 }
2421 e = e->ident_expression;
2422 } else if (e->type == EXPR_POS) {
2423 err = "internal front-end error: EXPR_POS in";
2424 break;
2425 } else
2426 return last;
2427 }
2428 expression_error(e, "%s initializer", err);
2429 return NULL;
2430 }
2431
2432 /*
2433 * choose the next subobject to initialize.
2434 *
2435 * Get designators for next element, switch old ones to EXPR_POS.
2436 * Return the resulting expression or NULL if we'd run out of subobjects.
2437 * The innermost designator is returned in *v. Designators in old
2438 * are assumed to be already sanity-checked.
2439 */
2440 static struct expression *next_designators(struct expression *old,
2441 struct symbol *ctype,
2442 struct expression *e, struct expression **v)
2443 {
2444 struct expression *new = NULL;
2445
2446 if (!old)
2447 return NULL;
2448 if (old->type == EXPR_INDEX) {
2449 struct expression *copy;
2450 unsigned n;
2451
2452 copy = next_designators(old->idx_expression,
2453 old->ctype, e, v);
2454 if (!copy) {
2455 n = old->idx_to + 1;
2456 if (array_element_offset(old->ctype->bit_size, n) == ctype->bit_size) {
2457 convert_index(old);
2458 return NULL;
2459 }
2460 copy = e;
2461 *v = new = alloc_expression(e->pos, EXPR_INDEX);
2462 } else {
2463 n = old->idx_to;
2464 new = alloc_expression(e->pos, EXPR_INDEX);
2465 }
2466
2467 new->idx_from = new->idx_to = n;
2468 new->idx_expression = copy;
2469 new->ctype = old->ctype;
2470 convert_index(old);
2471 } else if (old->type == EXPR_IDENTIFIER) {
2472 struct expression *copy;
2473 struct symbol *field;
2474 int offset = 0;
2475
2476 copy = next_designators(old->ident_expression,
2477 old->ctype, e, v);
2478 if (!copy) {
2479 field = old->field->next_subobject;
2480 if (!field) {
2481 convert_ident(old);
2482 return NULL;
2483 }
2484 copy = e;
2485 *v = new = alloc_expression(e->pos, EXPR_IDENTIFIER);
2486 /*
2487 * We can't necessarily trust "field->offset",
2488 * because the field might be in an anonymous
2489 * union, and the field offset is then the offset
2490 * within that union.
2491 *
2492 * The "old->offset - old->field->offset"
2493 * would be the offset of such an anonymous
2494 * union.
2495 */
2496 offset = old->offset - old->field->offset;
2497 } else {
2498 field = old->field;
2499 new = alloc_expression(e->pos, EXPR_IDENTIFIER);
2500 }
2501
2502 new->field = field;
2503 new->expr_ident = field->ident;
2504 new->ident_expression = copy;
2505 new->ctype = field;
2506 new->offset = field->offset + offset;
2507 convert_ident(old);
2508 }
2509 return new;
2510 }
2511
2512 static int handle_initializer(struct expression **ep, int nested,
2513 int class, struct symbol *ctype, unsigned long mods);
2514
2515 /*
2516 * deal with traversing subobjects [6.7.8(17,18,20)]
2517 */
2518 static void handle_list_initializer(struct expression *expr,
2519 int class, struct symbol *ctype, unsigned long mods)
2520 {
2521 struct expression *e, *last = NULL, *top = NULL, *next;
2522 int jumped = 0;
2523
2524 FOR_EACH_PTR(expr->expr_list, e) {
2525 struct expression **v;
2526 struct symbol *type;
2527 int lclass;
2528
2529 if (e->type != EXPR_INDEX && e->type != EXPR_IDENTIFIER) {
2530 struct symbol *struct_sym;
2531 if (!top) {
2532 top = e;
2533 last = first_subobject(ctype, class, &top);
2534 } else {
2535 last = next_designators(last, ctype, e, &top);
2536 }
2537 if (!last) {
2538 excess(e, class & TYPE_PTR ? "array" :
2539 "struct or union");
2540 DELETE_CURRENT_PTR(e);
2541 continue;
2542 }
2543 struct_sym = ctype->type == SYM_NODE ? ctype->ctype.base_type : ctype;
2544 if (Wdesignated_init && struct_sym->designated_init)
2545 warning(e->pos, "%s%.*s%spositional init of field in %s %s, declared with attribute designated_init",
2546 ctype->ident ? "in initializer for " : "",
2547 ctype->ident ? ctype->ident->len : 0,
2548 ctype->ident ? ctype->ident->name : "",
2549 ctype->ident ? ": " : "",
2550 get_type_name(struct_sym->type),
2551 show_ident(struct_sym->ident));
2552 if (jumped) {
2553 warning(e->pos, "advancing past deep designator");
2554 jumped = 0;
2555 }
2556 REPLACE_CURRENT_PTR(e, last);
2557 } else {
2558 next = check_designators(e, ctype);
2559 if (!next) {
2560 DELETE_CURRENT_PTR(e);
2561 continue;
2562 }
2563 top = next;
2564 /* deeper than one designator? */
2565 jumped = top != e;
2566 convert_designators(last);
2567 last = e;
2568 }
2569
2570 found:
2571 lclass = classify_type(top->ctype, &type);
2572 if (top->type == EXPR_INDEX)
2573 v = &top->idx_expression;
2574 else
2575 v = &top->ident_expression;
2576
2577 mods |= ctype->ctype.modifiers & MOD_STORAGE;
2578 if (handle_initializer(v, 1, lclass, top->ctype, mods))
2579 continue;
2580
2581 if (!(lclass & TYPE_COMPOUND)) {
2582 warning(e->pos, "bogus scalar initializer");
2583 DELETE_CURRENT_PTR(e);
2584 continue;
2585 }
2586
2587 next = first_subobject(type, lclass, v);
2588 if (next) {
2589 warning(e->pos, "missing braces around initializer");
2590 top = next;
2591 goto found;
2592 }
2593
2594 DELETE_CURRENT_PTR(e);
2595 excess(e, lclass & TYPE_PTR ? "array" : "struct or union");
2596
2597 } END_FOR_EACH_PTR(e);
2598
2599 convert_designators(last);
2600 expr->ctype = ctype;
2601 }
2602
2603 static int is_string_literal(struct expression **v)
2604 {
2605 struct expression *e = *v;
2606 while (e && e->type == EXPR_PREOP && e->op == '(')
2607 e = e->unop;
2608 if (!e || e->type != EXPR_STRING)
2609 return 0;
2610 if (e != *v && Wparen_string)
2611 warning(e->pos,
2612 "array initialized from parenthesized string constant");
2613 *v = e;
2614 return 1;
2615 }
2616
2617 /*
2618 * We want a normal expression, possibly in one layer of braces. Warn
2619 * if the latter happens inside a list (it's legal, but likely to be
2620 * an effect of screwup). In case of anything not legal, we are definitely
2621 * having an effect of screwup, so just fail and let the caller warn.
2622 */
2623 static struct expression *handle_scalar(struct expression *e, int nested)
2624 {
2625 struct expression *v = NULL, *p;
2626 int count = 0;
2627
2628 /* normal case */
2629 if (e->type != EXPR_INITIALIZER)
2630 return e;
2631
2632 FOR_EACH_PTR(e->expr_list, p) {
2633 if (!v)
2634 v = p;
2635 count++;
2636 } END_FOR_EACH_PTR(p);
2637 if (count != 1)
2638 return NULL;
2639 switch(v->type) {
2640 case EXPR_INITIALIZER:
2641 case EXPR_INDEX:
2642 case EXPR_IDENTIFIER:
2643 return NULL;
2644 default:
2645 break;
2646 }
2647 if (nested)
2648 warning(e->pos, "braces around scalar initializer");
2649 return v;
2650 }
2651
2652 /*
2653 * deal with the cases that don't care about subobjects:
2654 * scalar <- assignment expression, possibly in braces [6.7.8(11)]
2655 * character array <- string literal, possibly in braces [6.7.8(14)]
2656 * struct or union <- assignment expression of compatible type [6.7.8(13)]
2657 * compound type <- initializer list in braces [6.7.8(16)]
2658 * The last one punts to handle_list_initializer() which, in turn will call
2659 * us for individual elements of the list.
2660 *
2661 * We do not handle 6.7.8(15) (wide char array <- wide string literal) for
2662 * the lack of support of wide char stuff in general.
2663 *
2664 * One note: we need to take care not to evaluate a string literal until
2665 * we know that we *will* handle it right here. Otherwise we would screw
2666 * the cases like struct { struct {char s[10]; ...} ...} initialized with
2667 * { "string", ...} - we need to preserve that string literal recognizable
2668 * until we dig into the inner struct.
2669 */
2670 static int handle_initializer(struct expression **ep, int nested,
2671 int class, struct symbol *ctype, unsigned long mods)
2672 {
2673 int is_string = is_string_type(ctype);
2674 struct expression *e = *ep, *p;
2675 struct symbol *type;
2676
2677 if (!e)
2678 return 0;
2679
2680 /* scalar */
2681 if (!(class & TYPE_COMPOUND)) {
2682 e = handle_scalar(e, nested);
2683 if (!e)
2684 return 0;
2685 *ep = e;
2686 if (!evaluate_expression(e))
2687 return 1;
2688 compatible_assignment_types(e, ctype, ep, "initializer");
2689 /*
2690 * Initializers for static storage duration objects
2691 * shall be constant expressions or a string literal [6.7.8(4)].
2692 */
2693 mods |= ctype->ctype.modifiers;
2694 mods &= (MOD_TOPLEVEL | MOD_STATIC);
2695 if (mods && !(e->flags & (CEF_ACE | CEF_ADDR)))
2696 if (Wconstexpr_not_const)
2697 warning(e->pos, "non-constant initializer for static object");
2698
2699 return 1;
2700 }
2701
2702 /*
2703 * sublist; either a string, or we dig in; the latter will deal with
2704 * pathologies, so we don't need anything fancy here.
2705 */
2706 if (e->type == EXPR_INITIALIZER) {
2707 if (is_string) {
2708 struct expression *v = NULL;
2709 int count = 0;
2710
2711 FOR_EACH_PTR(e->expr_list, p) {
2712 if (!v)
2713 v = p;
2714 count++;
2715 } END_FOR_EACH_PTR(p);
2716 if (count == 1 && is_string_literal(&v)) {
2717 *ep = e = v;
2718 goto String;
2719 }
2720 }
2721 handle_list_initializer(e, class, ctype, mods);
2722 return 1;
2723 }
2724
2725 /* string */
2726 if (is_string_literal(&e)) {
2727 /* either we are doing array of char, or we'll have to dig in */
2728 if (is_string) {
2729 *ep = e;
2730 goto String;
2731 }
2732 return 0;
2733 }
2734 /* struct or union can be initialized by compatible */
2735 if (class != TYPE_COMPOUND)
2736 return 0;
2737 type = evaluate_expression(e);
2738 if (!type)
2739 return 0;
2740 if (ctype->type == SYM_NODE)
2741 ctype = ctype->ctype.base_type;
2742 if (type->type == SYM_NODE)
2743 type = type->ctype.base_type;
2744 if (ctype == type)
2745 return 1;
2746 return 0;
2747
2748 String:
2749 p = alloc_expression(e->pos, EXPR_STRING);
2750 *p = *e;
2751 type = evaluate_expression(p);
2752 if (ctype->bit_size != -1) {
2753 if (ctype->bit_size + bits_in_char < type->bit_size)
2754 warning(e->pos,
2755 "too long initializer-string for array of char");
2756 else if (Winit_cstring && ctype->bit_size + bits_in_char == type->bit_size) {
2757 warning(e->pos,
2758 "too long initializer-string for array of char(no space for nul char)");
2759 }
2760 }
2761 *ep = p;
2762 return 1;
2763 }
2764
2765 static void evaluate_initializer(struct symbol *ctype, struct expression **ep)
2766 {
2767 struct symbol *type;
2768 int class = classify_type(ctype, &type);
2769 if (!handle_initializer(ep, 0, class, ctype, 0))
2770 expression_error(*ep, "invalid initializer");
2771 }
2772
2773 static struct symbol *cast_to_bool(struct expression *expr)
2774 {
2775 struct expression *old = expr->cast_expression;
2776 struct expression *zero;
2777 struct symbol *otype;
2778 int oclass = classify_type(degenerate(old), &otype);
2779 struct symbol *ctype;
2780
2781 if (oclass & TYPE_COMPOUND)
2782 return NULL;
2783
2784 zero = alloc_const_expression(expr->pos, 0);
2785 expr->op = SPECIAL_NOTEQUAL;
2786 ctype = usual_conversions(expr->op, old, zero,
2787 oclass, TYPE_NUM, otype, zero->ctype);
2788 expr->type = EXPR_COMPARE;
2789 expr->left = cast_to(old, ctype);
2790 expr->right = cast_to(zero, ctype);
2791
2792 return expr->ctype;
2793 }
2794
2795 static int cast_flags(struct expression *expr, struct expression *old)
2796 {
2797 struct symbol *t;
2798 int class;
2799 int flags = CEF_NONE;
2800
2801 class = classify_type(expr->ctype, &t);
2802 if (class & TYPE_NUM) {
2803 flags = old->flags & ~CEF_CONST_MASK;
2804 /*
2805 * Casts to numeric types never result in address
2806 * constants [6.6(9)].
2807 */
2808 flags &= ~CEF_ADDR;
2809
2810 /*
2811 * As an extension, treat address constants cast to
2812 * integer type as an arithmetic constant.
2813 */
2814 if (old->flags & CEF_ADDR)
2815 flags = CEF_ACE;
2816
2817 /*
2818 * Cast to float type -> not an integer constant
2819 * expression [6.6(6)].
2820 */
2821 if (class & TYPE_FLOAT)
2822 flags &= ~CEF_CLR_ICE;
2823 /*
2824 * Casts of float literals to integer type results in
2825 * a constant integer expression [6.6(6)].
2826 */
2827 else if (old->flags & CEF_FLOAT)
2828 flags = CEF_SET_ICE;
2829 } else if (class & TYPE_PTR) {
2830 /*
2831 * Casts of integer literals to pointer type yield
2832 * address constants [6.6(9)].
2833 *
2834 * As an extension, treat address constants cast to a
2835 * different pointer type as address constants again.
2836 *
2837 * As another extension, treat integer constant
2838 * expressions (in contrast to literals) cast to
2839 * pointer type as address constants.
2840 */
2841 if (old->flags & (CEF_ICE | CEF_ADDR))
2842 flags = CEF_ADDR;
2843 }
2844
2845 return flags;
2846 }
2847
2848 static struct symbol *evaluate_cast(struct expression *expr)
2849 {
2850 struct expression *target = expr->cast_expression;
2851 struct symbol *ctype;
2852 struct symbol *t1, *t2;
2853 int class1, class2;
2854 int as1 = 0, as2 = 0;
2855
2856 if (!target)
2857 return NULL;
2858
2859 /*
2860 * Special case: a cast can be followed by an
2861 * initializer, in which case we need to pass
2862 * the type value down to that initializer rather
2863 * than trying to evaluate it as an expression
2864 *
2865 * A more complex case is when the initializer is
2866 * dereferenced as part of a post-fix expression.
2867 * We need to produce an expression that can be dereferenced.
2868 */
2869 if (target->type == EXPR_INITIALIZER) {
2870 struct symbol *sym = expr->cast_type;
2871 struct expression *addr = alloc_expression(expr->pos, EXPR_SYMBOL);
2872
2873 sym->initializer = target;
2874 evaluate_symbol(sym);
2875
2876 addr->ctype = &lazy_ptr_ctype; /* Lazy eval */
2877 addr->symbol = sym;
2878 if (sym->ctype.modifiers & MOD_TOPLEVEL)
2879 addr->flags |= CEF_ADDR;
2880
2881 expr->type = EXPR_PREOP;
2882 expr->op = '*';
2883 expr->unop = addr;
2884 expr->ctype = sym;
2885
2886 return sym;
2887 }
2888
2889 ctype = examine_symbol_type(expr->cast_type);
2890 expr->ctype = ctype;
2891 expr->cast_type = ctype;
2892
2893 evaluate_expression(target);
2894 degenerate(target);
2895
2896 class1 = classify_type(ctype, &t1);
2897
2898 expr->flags = cast_flags(expr, target);
2899
2900 /*
2901 * You can always throw a value away by casting to
2902 * "void" - that's an implicit "force". Note that
2903 * the same is _not_ true of "void *".
2904 */
2905 if (t1 == &void_ctype)
2906 goto out;
2907
2908 if (class1 & (TYPE_COMPOUND | TYPE_FN))
2909 warning(expr->pos, "cast to non-scalar");
2910
2911 t2 = target->ctype;
2912 if (!t2) {
2913 expression_error(expr, "cast from unknown type");
2914 goto out;
2915 }
2916 class2 = classify_type(t2, &t2);
2917
2918 if (class2 & TYPE_COMPOUND)
2919 warning(expr->pos, "cast from non-scalar");
2920
2921 if (expr->type == EXPR_FORCE_CAST)
2922 goto out;
2923
2924 /* allowed cast unfouls */
2925 if (class2 & TYPE_FOULED)
2926 t2 = unfoul(t2);
2927
2928 if (t1 != t2) {
2929 if ((class1 & TYPE_RESTRICT) && restricted_value(target, t1))
2930 warning(expr->pos, "cast to %s",
2931 show_typename(t1));
2932 if (class2 & TYPE_RESTRICT) {
2933 if (t1 == &bool_ctype) {
2934 if (class2 & TYPE_FOULED)
2935 warning(expr->pos, "%s degrades to integer",
2936 show_typename(t2));
2937 } else {
2938 warning(expr->pos, "cast from %s",
2939 show_typename(t2));
2940 }
2941 }
2942 }
2943
2944 if (t1 == &ulong_ctype)
2945 as1 = -1;
2946 else if (class1 == TYPE_PTR) {
2947 examine_pointer_target(t1);
2948 as1 = t1->ctype.as;
2949 }
2950
2951 if (t2 == &ulong_ctype)
2952 as2 = -1;
2953 else if (class2 == TYPE_PTR) {
2954 examine_pointer_target(t2);
2955 as2 = t2->ctype.as;
2956 }
2957
2958 if (!as1 && as2 > 0)
2959 warning(expr->pos, "cast removes address space of expression");
2960 if (as1 > 0 && as2 > 0 && as1 != as2)
2961 warning(expr->pos, "cast between address spaces (<asn:%d>-><asn:%d>)", as2, as1);
2962 if (as1 > 0 && !as2 &&
2963 !is_null_pointer_constant(target) && Wcast_to_as)
2964 warning(expr->pos,
2965 "cast adds address space to expression (<asn:%d>)", as1);
2966
2967 if (!(t1->ctype.modifiers & MOD_PTRINHERIT) && class1 == TYPE_PTR &&
2968 !as1 && (target->flags & CEF_ICE)) {
2969 if (t1->ctype.base_type == &void_ctype) {
2970 if (is_zero_constant(target)) {
2971 /* NULL */
2972 expr->type = EXPR_VALUE;
2973 expr->ctype = &null_ctype;
2974 expr->value = 0;
2975 return expr->ctype;
2976 }
2977 }
2978 }
2979
2980 if (t1 == &bool_ctype)
2981 cast_to_bool(expr);
2982
2983 out:
2984 return ctype;
2985 }
2986
2987 /*
2988 * Evaluate a call expression with a symbol. This
2989 * should expand inline functions, and evaluate
2990 * builtins.
2991 */
2992 static int evaluate_symbol_call(struct expression *expr)
2993 {
2994 struct expression *fn = expr->fn;
2995 struct symbol *ctype = fn->ctype;
2996
2997 if (fn->type != EXPR_PREOP)
2998 return 0;
2999
3000 if (ctype->op && ctype->op->evaluate)
3001 return ctype->op->evaluate(expr);
3002
3003 if (ctype->ctype.modifiers & MOD_INLINE) {
3004 int ret;
3005 struct symbol *curr = current_fn;
3006
3007 if (ctype->definition)
3008 ctype = ctype->definition;
3009
3010 current_fn = ctype->ctype.base_type;
3011
3012 ret = inline_function(expr, ctype);
3013
3014 /* restore the old function */
3015 current_fn = curr;
3016 return ret;
3017 }
3018
3019 return 0;
3020 }
3021
3022 static struct symbol *evaluate_call(struct expression *expr)
3023 {
3024 int args, fnargs;
3025 struct symbol *ctype, *sym;
3026 struct expression *fn = expr->fn;
3027 struct expression_list *arglist = expr->args;
3028
3029 if (!evaluate_expression(fn))
3030 return NULL;
3031 sym = ctype = fn->ctype;
3032 if (ctype->type == SYM_NODE)
3033 ctype = ctype->ctype.base_type;
3034 if (ctype->type == SYM_PTR)
3035 ctype = get_base_type(ctype);
3036
3037 if (ctype->type != SYM_FN) {
3038 struct expression *arg;
3039 expression_error(expr, "not a function %s",
3040 show_ident(sym->ident));
3041 /* do typechecking in arguments */
3042 FOR_EACH_PTR (arglist, arg) {
3043 evaluate_expression(arg);
3044 } END_FOR_EACH_PTR(arg);
3045 return NULL;
3046 }
3047
3048 examine_fn_arguments(ctype);
3049 if (sym->type == SYM_NODE && fn->type == EXPR_PREOP &&
3050 sym->op && sym->op->args) {
3051 if (!sym->op->args(expr))
3052 return NULL;
3053 } else {
3054 if (!evaluate_arguments(ctype, arglist))
3055 return NULL;
3056 args = expression_list_size(expr->args);
3057 fnargs = symbol_list_size(ctype->arguments);
3058 if (args < fnargs) {
3059 expression_error(expr,
3060 "not enough arguments for function %s",
3061 show_ident(sym->ident));
3062 return NULL;
3063 }
3064 if (args > fnargs && !ctype->variadic)
3065 expression_error(expr,
3066 "too many arguments for function %s",
3067 show_ident(sym->ident));
3068 }
3069 expr->ctype = ctype->ctype.base_type;
3070 if (sym->type == SYM_NODE) {
3071 if (evaluate_symbol_call(expr))
3072 return expr->ctype;
3073 }
3074 return expr->ctype;
3075 }
3076
3077 static struct symbol *evaluate_offsetof(struct expression *expr)
3078 {
3079 struct expression *e = expr->down;
3080 struct symbol *ctype = expr->in;
3081 int class;
3082
3083 if (expr->op == '.') {
3084 struct symbol *field;
3085 int offset = 0;
3086 if (!ctype) {
3087 expression_error(expr, "expected structure or union");
3088 return NULL;
3089 }
3090 examine_symbol_type(ctype);
3091 class = classify_type(ctype, &ctype);
3092 if (class != TYPE_COMPOUND) {
3093 expression_error(expr, "expected structure or union");
3094 return NULL;
3095 }
3096
3097 field = find_identifier(expr->ident, ctype->symbol_list, &offset);
3098 if (!field) {
3099 expression_error(expr, "unknown member");
3100 return NULL;
3101 }
3102 ctype = field;
3103 expr->type = EXPR_VALUE;
3104 expr->flags = CEF_SET_ICE;
3105 expr->value = offset;
3106 expr->taint = 0;
3107 expr->ctype = size_t_ctype;
3108 } else {
3109 if (!ctype) {
3110 expression_error(expr, "expected structure or union");
3111 return NULL;
3112 }
3113 examine_symbol_type(ctype);
3114 class = classify_type(ctype, &ctype);
3115 if (class != (TYPE_COMPOUND | TYPE_PTR)) {
3116 expression_error(expr, "expected array");
3117 return NULL;
3118 }
3119 ctype = ctype->ctype.base_type;
3120 if (!expr->index) {
3121 expr->type = EXPR_VALUE;
3122 expr->flags = CEF_SET_ICE;
3123 expr->value = 0;
3124 expr->taint = 0;
3125 expr->ctype = size_t_ctype;
3126 } else {
3127 struct expression *idx = expr->index, *m;
3128 struct symbol *i_type = evaluate_expression(idx);
3129 unsigned old_idx_flags;
3130 int i_class = classify_type(i_type, &i_type);
3131
3132 if (!is_int(i_class)) {
3133 expression_error(expr, "non-integer index");
3134 return NULL;
3135 }
3136 unrestrict(idx, i_class, &i_type);
3137 old_idx_flags = idx->flags;
3138 idx = cast_to(idx, size_t_ctype);
3139 idx->flags = old_idx_flags;
3140 m = alloc_const_expression(expr->pos,
3141 bits_to_bytes(ctype->bit_size));
3142 m->ctype = size_t_ctype;
3143 m->flags = CEF_SET_INT;
3144 expr->type = EXPR_BINOP;
3145 expr->left = idx;
3146 expr->right = m;
3147 expr->op = '*';
3148 expr->ctype = size_t_ctype;
3149 expr->flags = m->flags & idx->flags & ~CEF_CONST_MASK;
3150 }
3151 }
3152 if (e) {
3153 struct expression *copy = __alloc_expression(0);
3154 *copy = *expr;
3155 if (e->type == EXPR_OFFSETOF)
3156 e->in = ctype;
3157 if (!evaluate_expression(e))
3158 return NULL;
3159 expr->type = EXPR_BINOP;
3160 expr->flags = e->flags & copy->flags & ~CEF_CONST_MASK;
3161 expr->op = '+';
3162 expr->ctype = size_t_ctype;
3163 expr->left = copy;
3164 expr->right = e;
3165 }
3166 return size_t_ctype;
3167 }
3168
3169 struct symbol *evaluate_expression(struct expression *expr)
3170 {
3171 if (!expr)
3172 return NULL;
3173 if (expr->ctype)
3174 return expr->ctype;
3175
3176 switch (expr->type) {
3177 case EXPR_VALUE:
3178 case EXPR_FVALUE:
3179 expression_error(expr, "value expression without a type");
3180 return NULL;
3181 case EXPR_STRING:
3182 return evaluate_string(expr);
3183 case EXPR_SYMBOL:
3184 return evaluate_symbol_expression(expr);
3185 case EXPR_BINOP:
3186 if (!evaluate_expression(expr->left))
3187 return NULL;
3188 if (!evaluate_expression(expr->right))
3189 return NULL;
3190 return evaluate_binop(expr);
3191 case EXPR_LOGICAL:
3192 return evaluate_logical(expr);
3193 case EXPR_COMMA:
3194 evaluate_expression(expr->left);
3195 if (!evaluate_expression(expr->right))
3196 return NULL;
3197 return evaluate_comma(expr);
3198 case EXPR_COMPARE:
3199 if (!evaluate_expression(expr->left))
3200 return NULL;
3201 if (!evaluate_expression(expr->right))
3202 return NULL;
3203 return evaluate_compare(expr);
3204 case EXPR_ASSIGNMENT:
3205 if (!evaluate_expression(expr->left))
3206 return NULL;
3207 if (!evaluate_expression(expr->right))
3208 return NULL;
3209 return evaluate_assignment(expr);
3210 case EXPR_PREOP:
3211 if (!evaluate_expression(expr->unop))
3212 return NULL;
3213 return evaluate_preop(expr);
3214 case EXPR_POSTOP:
3215 if (!evaluate_expression(expr->unop))
3216 return NULL;
3217 return evaluate_postop(expr);
3218 case EXPR_CAST:
3219 case EXPR_FORCE_CAST:
3220 case EXPR_IMPLIED_CAST:
3221 return evaluate_cast(expr);
3222 case EXPR_SIZEOF:
3223 return evaluate_sizeof(expr);
3224 case EXPR_PTRSIZEOF:
3225 return evaluate_ptrsizeof(expr);
3226 case EXPR_ALIGNOF:
3227 return evaluate_alignof(expr);
3228 case EXPR_DEREF:
3229 return evaluate_member_dereference(expr);
3230 case EXPR_CALL:
3231 return evaluate_call(expr);
3232 case EXPR_SELECT:
3233 case EXPR_CONDITIONAL:
3234 return evaluate_conditional_expression(expr);
3235 case EXPR_STATEMENT:
3236 expr->ctype = evaluate_statement(expr->statement);
3237 return expr->ctype;
3238
3239 case EXPR_LABEL:
3240 expr->ctype = &ptr_ctype;
3241 return &ptr_ctype;
3242
3243 case EXPR_TYPE:
3244 /* Evaluate the type of the symbol .. */
3245 evaluate_symbol(expr->symbol);
3246 /* .. but the type of the _expression_ is a "type" */
3247 expr->ctype = &type_ctype;
3248 return &type_ctype;
3249
3250 case EXPR_OFFSETOF:
3251 return evaluate_offsetof(expr);
3252
3253 /* These can not exist as stand-alone expressions */
3254 case EXPR_INITIALIZER:
3255 case EXPR_IDENTIFIER:
3256 case EXPR_INDEX:
3257 case EXPR_POS:
3258 expression_error(expr, "internal front-end error: initializer in expression");
3259 return NULL;
3260 case EXPR_SLICE:
3261 expression_error(expr, "internal front-end error: SLICE re-evaluated");
3262 return NULL;
3263 }
3264 return NULL;
3265 }
3266
3267 static void check_duplicates(struct symbol *sym)
3268 {
3269 int declared = 0;
3270 struct symbol *next = sym;
3271 int initialized = sym->initializer != NULL;
3272
3273 while ((next = next->same_symbol) != NULL) {
3274 const char *typediff;
3275 evaluate_symbol(next);
3276 if (initialized && next->initializer) {
3277 sparse_error(sym->pos, "symbol '%s' has multiple initializers (originally initialized at %s:%d)",
3278 show_ident(sym->ident),
3279 stream_name(next->pos.stream), next->pos.line);
3280 /* Only warn once */
3281 initialized = 0;
3282 }
3283 declared++;
3284 typediff = type_difference(&sym->ctype, &next->ctype, 0, 0);
3285 if (typediff) {
3286 sparse_error(sym->pos, "symbol '%s' redeclared with different type (originally declared at %s:%d) - %s",
3287 show_ident(sym->ident),
3288 stream_name(next->pos.stream), next->pos.line, typediff);
3289 return;
3290 }
3291 }
3292 if (!declared) {
3293 unsigned long mod = sym->ctype.modifiers;
3294 if (mod & (MOD_STATIC | MOD_REGISTER))
3295 return;
3296 if (!(mod & MOD_TOPLEVEL))
3297 return;
3298 if (!Wdecl)
3299 return;
3300 if (sym->ident == &main_ident)
3301 return;
3302 warning(sym->pos, "symbol '%s' was not declared. Should it be static?", show_ident(sym->ident));
3303 }
3304 }
3305
3306 static struct symbol *evaluate_symbol(struct symbol *sym)
3307 {
3308 struct symbol *base_type;
3309
3310 if (!sym)
3311 return sym;
3312 if (sym->evaluated)
3313 return sym;
3314 sym->evaluated = 1;
3315
3316 sym = examine_symbol_type(sym);
3317 base_type = get_base_type(sym);
3318 if (!base_type)
3319 return NULL;
3320
3321 /* Evaluate the initializers */
3322 if (sym->initializer)
3323 evaluate_initializer(sym, &sym->initializer);
3324
3325 /* And finally, evaluate the body of the symbol too */
3326 if (base_type->type == SYM_FN) {
3327 struct symbol *curr = current_fn;
3328
3329 if (sym->definition && sym->definition != sym)
3330 return evaluate_symbol(sym->definition);
3331
3332 current_fn = base_type;
3333
3334 examine_fn_arguments(base_type);
3335 if (!base_type->stmt && base_type->inline_stmt)
3336 uninline(sym);
3337 if (base_type->stmt)
3338 evaluate_statement(base_type->stmt);
3339
3340 current_fn = curr;
3341 }
3342
3343 return base_type;
3344 }
3345
3346 void evaluate_symbol_list(struct symbol_list *list)
3347 {
3348 struct symbol *sym;
3349
3350 FOR_EACH_PTR(list, sym) {
3351 has_error &= ~ERROR_CURR_PHASE;
3352 evaluate_symbol(sym);
3353 check_duplicates(sym);
3354 } END_FOR_EACH_PTR(sym);
3355 }
3356
3357 static struct symbol *evaluate_return_expression(struct statement *stmt)
3358 {
3359 struct expression *expr = stmt->expression;
3360 struct symbol *fntype;
3361
3362 evaluate_expression(expr);
3363 fntype = current_fn->ctype.base_type;
3364 if (!fntype || fntype == &void_ctype) {
3365 if (expr && expr->ctype != &void_ctype)
3366 expression_error(expr, "return expression in %s function", fntype?"void":"typeless");
3367 if (expr && Wreturn_void)
3368 warning(stmt->pos, "returning void-valued expression");
3369 return NULL;
3370 }
3371
3372 if (!expr) {
3373 sparse_error(stmt->pos, "return with no return value");
3374 return NULL;
3375 }
3376 if (!expr->ctype)
3377 return NULL;
3378 compatible_assignment_types(expr, fntype, &stmt->expression, "return expression");
3379 return NULL;
3380 }
3381
3382 static void evaluate_if_statement(struct statement *stmt)
3383 {
3384 if (!stmt->if_conditional)
3385 return;
3386
3387 evaluate_conditional(stmt->if_conditional, 0);
3388 evaluate_statement(stmt->if_true);
3389 evaluate_statement(stmt->if_false);
3390 }
3391
3392 static void evaluate_iterator(struct statement *stmt)
3393 {
3394 evaluate_symbol_list(stmt->iterator_syms);
3395 evaluate_conditional(stmt->iterator_pre_condition, 1);
3396 evaluate_conditional(stmt->iterator_post_condition,1);
3397 evaluate_statement(stmt->iterator_pre_statement);
3398 evaluate_statement(stmt->iterator_statement);
3399 evaluate_statement(stmt->iterator_post_statement);
3400 }
3401
3402 static void verify_output_constraint(struct expression *expr, const char *constraint)
3403 {
3404 switch (*constraint) {
3405 case '=': /* Assignment */
3406 case '+': /* Update */
3407 break;
3408 default:
3409 expression_error(expr, "output constraint is not an assignment constraint (\"%s\")", constraint);
3410 }
3411 }
3412
3413 static void verify_input_constraint(struct expression *expr, const char *constraint)
3414 {
3415 switch (*constraint) {
3416 case '=': /* Assignment */
3417 case '+': /* Update */
3418 expression_error(expr, "input constraint with assignment (\"%s\")", constraint);
3419 }
3420 }
3421
3422 static void evaluate_asm_statement(struct statement *stmt)
3423 {
3424 struct expression *expr;
3425 struct symbol *sym;
3426 int state;
3427
3428 expr = stmt->asm_string;
3429 if (!expr || expr->type != EXPR_STRING) {
3430 sparse_error(stmt->pos, "need constant string for inline asm");
3431 return;
3432 }
3433
3434 state = 0;
3435 FOR_EACH_PTR(stmt->asm_outputs, expr) {
3436 switch (state) {
3437 case 0: /* Identifier */
3438 state = 1;
3439 continue;
3440
3441 case 1: /* Constraint */
3442 state = 2;
3443 if (!expr || expr->type != EXPR_STRING) {
3444 sparse_error(expr ? expr->pos : stmt->pos, "asm output constraint is not a string");
3445 *THIS_ADDRESS(expr) = NULL;
3446 continue;
3447 }
3448 verify_output_constraint(expr, expr->string->data);
3449 continue;
3450
3451 case 2: /* Expression */
3452 state = 0;
3453 if (!evaluate_expression(expr))
3454 return;
3455 if (!lvalue_expression(expr))
3456 warning(expr->pos, "asm output is not an lvalue");
3457 evaluate_assign_to(expr, expr->ctype);
3458 continue;
3459 }
3460 } END_FOR_EACH_PTR(expr);
3461
3462 state = 0;
3463 FOR_EACH_PTR(stmt->asm_inputs, expr) {
3464 switch (state) {
3465 case 0: /* Identifier */
3466 state = 1;
3467 continue;
3468
3469 case 1: /* Constraint */
3470 state = 2;
3471 if (!expr || expr->type != EXPR_STRING) {
3472 sparse_error(expr ? expr->pos : stmt->pos, "asm input constraint is not a string");
3473 *THIS_ADDRESS(expr) = NULL;
3474 continue;
3475 }
3476 verify_input_constraint(expr, expr->string->data);
3477 continue;
3478
3479 case 2: /* Expression */
3480 state = 0;
3481 if (!evaluate_expression(expr))
3482 return;
3483 continue;
3484 }
3485 } END_FOR_EACH_PTR(expr);
3486
3487 FOR_EACH_PTR(stmt->asm_clobbers, expr) {
3488 if (!expr) {
3489 sparse_error(stmt->pos, "bad asm clobbers");
3490 return;
3491 }
3492 if (expr->type == EXPR_STRING)
3493 continue;
3494 expression_error(expr, "asm clobber is not a string");
3495 } END_FOR_EACH_PTR(expr);
3496
3497 FOR_EACH_PTR(stmt->asm_labels, sym) {
3498 if (!sym || sym->type != SYM_LABEL) {
3499 sparse_error(stmt->pos, "bad asm label");
3500 return;
3501 }
3502 } END_FOR_EACH_PTR(sym);
3503 }
3504
3505 static void evaluate_case_statement(struct statement *stmt)
3506 {
3507 evaluate_expression(stmt->case_expression);
3508 evaluate_expression(stmt->case_to);
3509 evaluate_statement(stmt->case_statement);
3510 }
3511
3512 static void check_case_type(struct expression *switch_expr,
3513 struct expression *case_expr,
3514 struct expression **enumcase)
3515 {
3516 struct symbol *switch_type, *case_type;
3517 int sclass, cclass;
3518
3519 if (!case_expr)
3520 return;
3521
3522 switch_type = switch_expr->ctype;
3523 case_type = evaluate_expression(case_expr);
3524
3525 if (!switch_type || !case_type)
3526 goto Bad;
3527 if (enumcase) {
3528 if (*enumcase)
3529 warn_for_different_enum_types(case_expr->pos, case_type, (*enumcase)->ctype);
3530 else if (is_enum_type(case_type))
3531 *enumcase = case_expr;
3532 }
3533
3534 sclass = classify_type(switch_type, &switch_type);
3535 cclass = classify_type(case_type, &case_type);
3536
3537 /* both should be arithmetic */
3538 if (!(sclass & cclass & TYPE_NUM))
3539 goto Bad;
3540
3541 /* neither should be floating */
3542 if ((sclass | cclass) & TYPE_FLOAT)
3543 goto Bad;
3544
3545 /* if neither is restricted, we are OK */
3546 if (!((sclass | cclass) & TYPE_RESTRICT))
3547 return;
3548
3549 if (!restricted_binop_type(SPECIAL_EQUAL, case_expr, switch_expr,
3550 cclass, sclass, case_type, switch_type)) {
3551 unrestrict(case_expr, cclass, &case_type);
3552 unrestrict(switch_expr, sclass, &switch_type);
3553 }
3554 return;
3555
3556 Bad:
3557 expression_error(case_expr, "incompatible types for 'case' statement");
3558 }
3559
3560 static void evaluate_switch_statement(struct statement *stmt)
3561 {
3562 struct symbol *sym;
3563 struct expression *enumcase = NULL;
3564 struct expression **enumcase_holder = &enumcase;
3565 struct expression *sel = stmt->switch_expression;
3566
3567 evaluate_expression(sel);
3568 evaluate_statement(stmt->switch_statement);
3569 if (!sel)
3570 return;
3571 if (sel->ctype && is_enum_type(sel->ctype))
3572 enumcase_holder = NULL; /* Only check cases against switch */
3573
3574 FOR_EACH_PTR(stmt->switch_case->symbol_list, sym) {
3575 struct statement *case_stmt = sym->stmt;
3576 check_case_type(sel, case_stmt->case_expression, enumcase_holder);
3577 check_case_type(sel, case_stmt->case_to, enumcase_holder);
3578 } END_FOR_EACH_PTR(sym);
3579 }
3580
3581 static void evaluate_goto_statement(struct statement *stmt)
3582 {
3583 struct symbol *label = stmt->goto_label;
3584
3585 if (label && !label->stmt && !lookup_keyword(label->ident, NS_KEYWORD))
3586 sparse_error(stmt->pos, "label '%s' was not declared", show_ident(label->ident));
3587
3588 evaluate_expression(stmt->goto_expression);
3589 }
3590
3591 struct symbol *evaluate_statement(struct statement *stmt)
3592 {
3593 if (!stmt)
3594 return NULL;
3595
3596 switch (stmt->type) {
3597 case STMT_DECLARATION: {
3598 struct symbol *s;
3599 FOR_EACH_PTR(stmt->declaration, s) {
3600 evaluate_symbol(s);
3601 } END_FOR_EACH_PTR(s);
3602 return NULL;
3603 }
3604
3605 case STMT_RETURN:
3606 return evaluate_return_expression(stmt);
3607
3608 case STMT_EXPRESSION:
3609 if (!evaluate_expression(stmt->expression))
3610 return NULL;
3611 if (stmt->expression->ctype == &null_ctype)
3612 stmt->expression = cast_to(stmt->expression, &ptr_ctype);
3613 return degenerate(stmt->expression);
3614
3615 case STMT_COMPOUND: {
3616 struct statement *s;
3617 struct symbol *type = NULL;
3618
3619 /* Evaluate the return symbol in the compound statement */
3620 evaluate_symbol(stmt->ret);
3621
3622 /*
3623 * Then, evaluate each statement, making the type of the
3624 * compound statement be the type of the last statement
3625 */
3626 type = evaluate_statement(stmt->args);
3627 FOR_EACH_PTR(stmt->stmts, s) {
3628 type = evaluate_statement(s);
3629 } END_FOR_EACH_PTR(s);
3630 if (!type)
3631 type = &void_ctype;
3632 return type;
3633 }
3634 case STMT_IF:
3635 evaluate_if_statement(stmt);
3636 return NULL;
3637 case STMT_ITERATOR:
3638 evaluate_iterator(stmt);
3639 return NULL;
3640 case STMT_SWITCH:
3641 evaluate_switch_statement(stmt);
3642 return NULL;
3643 case STMT_CASE:
3644 evaluate_case_statement(stmt);
3645 return NULL;
3646 case STMT_LABEL:
3647 return evaluate_statement(stmt->label_statement);
3648 case STMT_GOTO:
3649 evaluate_goto_statement(stmt);
3650 return NULL;
3651 case STMT_NONE:
3652 break;
3653 case STMT_ASM:
3654 evaluate_asm_statement(stmt);
3655 return NULL;
3656 case STMT_CONTEXT:
3657 evaluate_expression(stmt->expression);
3658 return NULL;
3659 case STMT_RANGE:
3660 evaluate_expression(stmt->range_expression);
3661 evaluate_expression(stmt->range_low);
3662 evaluate_expression(stmt->range_high);
3663 return NULL;
3664 }
3665 return NULL;
3666 }