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[PATCH] in case of compound literal we want to delay examining type
[smatch.git] / evaluate.c
blobe3b49407024eedd405094af3feabe08b4cbf2ee6
1 /*
2 * sparse/evaluate.c
3 *
4 * Copyright (C) 2003 Transmeta Corp.
5 * 2003-2004 Linus Torvalds
6 *
7 * Licensed under the Open Software License version 1.1
8 *
9 * Evaluate constant expressions.
10 */
11 #include <stdlib.h>
12 #include <stdarg.h>
13 #include <stddef.h>
14 #include <stdio.h>
15 #include <string.h>
16 #include <ctype.h>
17 #include <unistd.h>
18 #include <fcntl.h>
19 #include <limits.h>
20
21 #include "lib.h"
22 #include "allocate.h"
23 #include "parse.h"
24 #include "token.h"
25 #include "symbol.h"
26 #include "target.h"
27 #include "expression.h"
28
29 struct symbol *current_fn;
30
31 static struct symbol *degenerate(struct expression *expr);
32 static struct symbol *evaluate_symbol(struct symbol *sym);
33
34 static struct symbol *evaluate_symbol_expression(struct expression *expr)
35 {
36 struct expression *addr;
37 struct symbol *sym = expr->symbol;
38 struct symbol *base_type;
39
40 if (!sym) {
41 expression_error(expr, "undefined identifier '%s'", show_ident(expr->symbol_name));
42 return NULL;
43 }
44
45 examine_symbol_type(sym);
46
47 base_type = get_base_type(sym);
48 if (!base_type) {
49 expression_error(expr, "identifier '%s' has no type", show_ident(expr->symbol_name));
50 return NULL;
51 }
52
53 addr = alloc_expression(expr->pos, EXPR_SYMBOL);
54 addr->symbol = sym;
55 addr->symbol_name = expr->symbol_name;
56 addr->ctype = &lazy_ptr_ctype; /* Lazy evaluation: we need to do a proper job if somebody does &sym */
57 expr->type = EXPR_PREOP;
58 expr->op = '*';
59 expr->unop = addr;
60
61 /* The type of a symbol is the symbol itself! */
62 expr->ctype = sym;
63 return sym;
64 }
65
66 static struct symbol *evaluate_string(struct expression *expr)
67 {
68 struct symbol *sym = alloc_symbol(expr->pos, SYM_NODE);
69 struct symbol *array = alloc_symbol(expr->pos, SYM_ARRAY);
70 struct expression *addr = alloc_expression(expr->pos, EXPR_SYMBOL);
71 struct expression *initstr = alloc_expression(expr->pos, EXPR_STRING);
72 unsigned int length = expr->string->length;
73
74 sym->array_size = alloc_const_expression(expr->pos, length);
75 sym->bit_size = bits_in_char * length;
76 sym->ctype.alignment = 1;
77 sym->string = 1;
78 sym->ctype.modifiers = MOD_STATIC;
79 sym->ctype.base_type = array;
80 sym->initializer = initstr;
81
82 initstr->ctype = sym;
83 initstr->string = expr->string;
84
85 array->array_size = sym->array_size;
86 array->bit_size = bits_in_char * length;
87 array->ctype.alignment = 1;
88 array->ctype.modifiers = MOD_STATIC;
89 array->ctype.base_type = &char_ctype;
90
91 addr->symbol = sym;
92 addr->ctype = &lazy_ptr_ctype;
93
94 expr->type = EXPR_PREOP;
95 expr->op = '*';
96 expr->unop = addr;
97 expr->ctype = sym;
98 return sym;
99 }
100
101 static inline struct symbol *integer_promotion(struct symbol *type)
102 {
103 struct symbol *orig_type = type;
104 unsigned long mod = type->ctype.modifiers;
105 int width;
106
107 if (type->type == SYM_NODE)
108 type = type->ctype.base_type;
109 if (type->type == SYM_ENUM)
110 type = type->ctype.base_type;
111 width = type->bit_size;
112
113 /*
114 * Bitfields always promote to the base type,
115 * even if the bitfield might be bigger than
116 * an "int".
117 */
118 if (type->type == SYM_BITFIELD) {
119 type = type->ctype.base_type;
120 orig_type = type;
121 }
122 mod = type->ctype.modifiers;
123 if (width < bits_in_int)
124 return &int_ctype;
125
126 /* If char/short has as many bits as int, it still gets "promoted" */
127 if (mod & (MOD_CHAR | MOD_SHORT)) {
128 if (mod & MOD_UNSIGNED)
129 return &uint_ctype;
130 return &int_ctype;
131 }
132 return orig_type;
133 }
134
135 /*
136 * integer part of usual arithmetic conversions:
137 * integer promotions are applied
138 * if left and right are identical, we are done
139 * if signedness is the same, convert one with lower rank
140 * unless unsigned argument has rank lower than signed one, convert the
141 * signed one.
142 * if signed argument is bigger than unsigned one, convert the unsigned.
143 * otherwise, convert signed.
144 *
145 * Leaving aside the integer promotions, that is equivalent to
146 * if identical, don't convert
147 * if left is bigger than right, convert right
148 * if right is bigger than left, convert right
149 * otherwise, if signedness is the same, convert one with lower rank
150 * otherwise convert the signed one.
151 */
152 static struct symbol *bigger_int_type(struct symbol *left, struct symbol *right)
153 {
154 unsigned long lmod, rmod;
155
156 left = integer_promotion(left);
157 right = integer_promotion(right);
158
159 if (left == right)
160 goto left;
161
162 if (left->bit_size > right->bit_size)
163 goto left;
164
165 if (right->bit_size > left->bit_size)
166 goto right;
167
168 lmod = left->ctype.modifiers;
169 rmod = right->ctype.modifiers;
170 if ((lmod ^ rmod) & MOD_UNSIGNED) {
171 if (lmod & MOD_UNSIGNED)
172 goto left;
173 } else if ((lmod & ~rmod) & (MOD_LONG | MOD_LONGLONG))
174 goto left;
175 right:
176 left = right;
177 left:
178 return left;
179 }
180
181 static int same_cast_type(struct symbol *orig, struct symbol *new)
182 {
183 return orig->bit_size == new->bit_size && orig->bit_offset == new->bit_offset;
184 }
185
186 static struct symbol *base_type(struct symbol *node, unsigned long *modp, unsigned long *asp)
187 {
188 unsigned long mod, as;
189
190 mod = 0; as = 0;
191 while (node) {
192 mod |= node->ctype.modifiers;
193 as |= node->ctype.as;
194 if (node->type == SYM_NODE) {
195 node = node->ctype.base_type;
196 continue;
197 }
198 break;
199 }
200 *modp = mod & ~MOD_IGNORE;
201 *asp = as;
202 return node;
203 }
204
205 static int is_same_type(struct expression *expr, struct symbol *new)
206 {
207 struct symbol *old = expr->ctype;
208 unsigned long oldmod, newmod, oldas, newas;
209
210 old = base_type(old, &oldmod, &oldas);
211 new = base_type(new, &newmod, &newas);
212
213 /* Same base type, same address space? */
214 if (old == new && oldas == newas) {
215 unsigned long difmod;
216
217 /* Check the modifier bits. */
218 difmod = (oldmod ^ newmod) & ~MOD_NOCAST;
219
220 /* Exact same type? */
221 if (!difmod)
222 return 1;
223
224 /*
225 * Not the same type, but differs only in "const".
226 * Don't warn about MOD_NOCAST.
227 */
228 if (difmod == MOD_CONST)
229 return 0;
230 }
231 if ((oldmod | newmod) & MOD_NOCAST) {
232 const char *tofrom = "to/from";
233 if (!(newmod & MOD_NOCAST))
234 tofrom = "from";
235 if (!(oldmod & MOD_NOCAST))
236 tofrom = "to";
237 warning(expr->pos, "implicit cast %s nocast type", tofrom);
238 }
239 return 0;
240 }
241
242 static void
243 warn_for_different_enum_types (struct position pos,
244 struct symbol *typea,
245 struct symbol *typeb)
246 {
247 if (!Wenum_mismatch)
248 return;
249 if (typea->type == SYM_NODE)
250 typea = typea->ctype.base_type;
251 if (typeb->type == SYM_NODE)
252 typeb = typeb->ctype.base_type;
253
254 if (typea == typeb)
255 return;
256
257 if (typea->type == SYM_ENUM && typeb->type == SYM_ENUM) {
258 warning(pos, "mixing different enum types");
259 info(pos, " %s versus", show_typename(typea));
260 info(pos, " %s", show_typename(typeb));
261 }
262 }
263
264 /*
265 * This gets called for implicit casts in assignments and
266 * integer promotion. We often want to try to move the
267 * cast down, because the ops involved may have been
268 * implicitly cast up, and we can get rid of the casts
269 * early.
270 */
271 static struct expression * cast_to(struct expression *old, struct symbol *type)
272 {
273 struct expression *expr;
274
275 warn_for_different_enum_types (old->pos, old->ctype, type);
276
277 if (is_same_type(old, type))
278 return old;
279
280 /*
281 * See if we can simplify the op. Move the cast down.
282 */
283 switch (old->type) {
284 case EXPR_PREOP:
285 if (old->ctype->bit_size < type->bit_size)
286 break;
287 if (old->op == '~') {
288 old->ctype = type;
289 old->unop = cast_to(old->unop, type);
290 return old;
291 }
292 break;
293
294 case EXPR_IMPLIED_CAST:
295 warn_for_different_enum_types(old->pos, old->ctype, type);
296
297 if (old->ctype->bit_size >= type->bit_size) {
298 struct expression *orig = old->cast_expression;
299 if (same_cast_type(orig->ctype, type))
300 return orig;
301 if (old->ctype->bit_offset == type->bit_offset) {
302 old->ctype = type;
303 old->cast_type = type;
304 return old;
305 }
306 }
307 break;
308
309 default:
310 /* nothing */;
311 }
312
313 expr = alloc_expression(old->pos, EXPR_IMPLIED_CAST);
314 expr->ctype = type;
315 expr->cast_type = type;
316 expr->cast_expression = old;
317 return expr;
318 }
319
320 static int is_type_type(struct symbol *type)
321 {
322 return (type->ctype.modifiers & MOD_TYPE) != 0;
323 }
324
325 int is_ptr_type(struct symbol *type)
326 {
327 if (type->type == SYM_NODE)
328 type = type->ctype.base_type;
329 return type->type == SYM_PTR || type->type == SYM_ARRAY || type->type == SYM_FN;
330 }
331
332 static inline int is_float_type(struct symbol *type)
333 {
334 if (type->type == SYM_NODE)
335 type = type->ctype.base_type;
336 return type->ctype.base_type == &fp_type;
337 }
338
339 static inline int is_byte_type(struct symbol *type)
340 {
341 return type->bit_size == bits_in_char && type->type != SYM_BITFIELD;
342 }
343
344 enum {
345 TYPE_NUM = 1,
346 TYPE_BITFIELD = 2,
347 TYPE_RESTRICT = 4,
348 TYPE_FLOAT = 8,
349 TYPE_PTR = 16,
350 TYPE_COMPOUND = 32,
351 TYPE_FOULED = 64,
352 };
353
354 static inline int classify_type(struct symbol *type, struct symbol **base)
355 {
356 static int type_class[SYM_BAD + 1] = {
357 [SYM_PTR] = TYPE_PTR,
358 [SYM_FN] = TYPE_PTR,
359 [SYM_ARRAY] = TYPE_PTR | TYPE_COMPOUND,
360 [SYM_STRUCT] = TYPE_COMPOUND,
361 [SYM_UNION] = TYPE_COMPOUND,
362 [SYM_BITFIELD] = TYPE_NUM | TYPE_BITFIELD,
363 [SYM_RESTRICT] = TYPE_NUM | TYPE_RESTRICT,
364 [SYM_FOULED] = TYPE_NUM | TYPE_RESTRICT | TYPE_FOULED,
365 };
366 if (type->type == SYM_NODE)
367 type = type->ctype.base_type;
368 if (type->type == SYM_ENUM)
369 type = type->ctype.base_type;
370 *base = type;
371 if (type->type == SYM_BASETYPE) {
372 if (type->ctype.base_type == &int_type)
373 return TYPE_NUM;
374 if (type->ctype.base_type == &fp_type)
375 return TYPE_NUM | TYPE_FLOAT;
376 }
377 return type_class[type->type];
378 }
379
380 #define is_int(class) ((class & (TYPE_NUM | TYPE_FLOAT)) == TYPE_NUM)
381
382 static inline int is_string_type(struct symbol *type)
383 {
384 if (type->type == SYM_NODE)
385 type = type->ctype.base_type;
386 return type->type == SYM_ARRAY && is_byte_type(type->ctype.base_type);
387 }
388
389 static struct symbol *bad_expr_type(struct expression *expr)
390 {
391 sparse_error(expr->pos, "incompatible types for operation (%s)", show_special(expr->op));
392 switch (expr->type) {
393 case EXPR_BINOP:
394 case EXPR_COMPARE:
395 info(expr->pos, " left side has type %s", show_typename(expr->left->ctype));
396 info(expr->pos, " right side has type %s", show_typename(expr->right->ctype));
397 break;
398 case EXPR_PREOP:
399 case EXPR_POSTOP:
400 info(expr->pos, " argument has type %s", show_typename(expr->unop->ctype));
401 break;
402 default:
403 break;
404 }
405
406 return expr->ctype = &bad_ctype;
407 }
408
409 static int restricted_value(struct expression *v, struct symbol *type)
410 {
411 if (v->type != EXPR_VALUE)
412 return 1;
413 if (v->value != 0)
414 return 1;
415 return 0;
416 }
417
418 static int restricted_binop(int op, struct symbol *type)
419 {
420 switch (op) {
421 case '&':
422 case '=':
423 case SPECIAL_AND_ASSIGN:
424 case SPECIAL_OR_ASSIGN:
425 case SPECIAL_XOR_ASSIGN:
426 return 1; /* unfoul */
427 case '|':
428 case '^':
429 case '?':
430 return 2; /* keep fouled */
431 case SPECIAL_EQUAL:
432 case SPECIAL_NOTEQUAL:
433 return 3; /* warn if fouled */
434 default:
435 return 0; /* warn */
436 }
437 }
438
439 static int restricted_unop(int op, struct symbol **type)
440 {
441 if (op == '~') {
442 if ((*type)->bit_size < bits_in_int)
443 *type = befoul(*type);
444 return 0;
445 } if (op == '+')
446 return 0;
447 return 1;
448 }
449
450 static struct symbol *restricted_binop_type(int op,
451 struct expression *left,
452 struct expression *right,
453 int lclass, int rclass,
454 struct symbol *ltype,
455 struct symbol *rtype)
456 {
457 struct symbol *ctype = NULL;
458 if (lclass & TYPE_RESTRICT) {
459 if (rclass & TYPE_RESTRICT) {
460 if (ltype == rtype) {
461 ctype = ltype;
462 } else if (lclass & TYPE_FOULED) {
463 if (ltype->ctype.base_type == rtype)
464 ctype = ltype;
465 } else if (rclass & TYPE_FOULED) {
466 if (rtype->ctype.base_type == ltype)
467 ctype = rtype;
468 }
469 } else {
470 if (!restricted_value(right, ltype))
471 ctype = ltype;
472 }
473 } else if (!restricted_value(left, rtype))
474 ctype = rtype;
475
476 if (ctype) {
477 switch (restricted_binop(op, ctype)) {
478 case 1:
479 if ((lclass ^ rclass) & TYPE_FOULED)
480 ctype = ctype->ctype.base_type;
481 break;
482 case 3:
483 if (!(lclass & rclass & TYPE_FOULED))
484 break;
485 case 0:
486 ctype = NULL;
487 default:
488 break;
489 }
490 }
491
492 return ctype;
493 }
494
495 static inline void unrestrict(struct expression *expr,
496 int class, struct symbol **ctype)
497 {
498 if (class & TYPE_RESTRICT) {
499 warning(expr->pos, "restricted degrades to integer");
500 if (class & TYPE_FOULED) /* unfoul it first */
501 *ctype = (*ctype)->ctype.base_type;
502 *ctype = (*ctype)->ctype.base_type; /* get to arithmetic type */
503 }
504 }
505
506 static struct symbol *usual_conversions(int op,
507 struct expression *left,
508 struct expression *right,
509 int lclass, int rclass,
510 struct symbol *ltype,
511 struct symbol *rtype)
512 {
513 struct symbol *ctype;
514
515 warn_for_different_enum_types(right->pos, left->ctype, right->ctype);
516
517 if ((lclass | rclass) & TYPE_RESTRICT)
518 goto Restr;
519
520 Normal:
521 if (!(lclass & TYPE_FLOAT)) {
522 if (!(rclass & TYPE_FLOAT))
523 return bigger_int_type(ltype, rtype);
524 else
525 return rtype;
526 } else if (rclass & TYPE_FLOAT) {
527 unsigned long lmod = ltype->ctype.modifiers;
528 unsigned long rmod = rtype->ctype.modifiers;
529 if (rmod & ~lmod & (MOD_LONG | MOD_LONGLONG))
530 return rtype;
531 else
532 return ltype;
533 } else
534 return ltype;
535
536 Restr:
537 ctype = restricted_binop_type(op, left, right,
538 lclass, rclass, ltype, rtype);
539 if (ctype)
540 return ctype;
541
542 unrestrict(left, lclass, &ltype);
543 unrestrict(right, rclass, &rtype);
544
545 goto Normal;
546 }
547
548 static inline int lvalue_expression(struct expression *expr)
549 {
550 return expr->type == EXPR_PREOP && expr->op == '*';
551 }
552
553 static int ptr_object_size(struct symbol *ptr_type)
554 {
555 if (ptr_type->type == SYM_NODE)
556 ptr_type = ptr_type->ctype.base_type;
557 if (ptr_type->type == SYM_PTR)
558 ptr_type = get_base_type(ptr_type);
559 return ptr_type->bit_size;
560 }
561
562 static struct symbol *evaluate_ptr_add(struct expression *expr, struct symbol *ctype, struct symbol *itype)
563 {
564 struct expression *index = expr->right;
565 int multiply;
566 int bit_size;
567
568 examine_symbol_type(ctype);
569
570 if (!ctype->ctype.base_type) {
571 expression_error(expr, "missing type information");
572 return NULL;
573 }
574
575 /* Get the size of whatever the pointer points to */
576 bit_size = ptr_object_size(ctype);
577 multiply = bit_size >> 3;
578
579 expr->ctype = ctype;
580
581 if (multiply == 1 && itype->bit_size >= bits_in_pointer)
582 return ctype;
583
584 if (index->type == EXPR_VALUE) {
585 struct expression *val = alloc_expression(expr->pos, EXPR_VALUE);
586 unsigned long long v = index->value, mask;
587 mask = 1ULL << (itype->bit_size - 1);
588 if (v & mask)
589 v |= -mask;
590 else
591 v &= mask - 1;
592 v *= multiply;
593 mask = 1ULL << (bits_in_pointer - 1);
594 v &= mask | (mask - 1);
595 val->value = v;
596 val->ctype = ssize_t_ctype;
597 expr->right = val;
598 return ctype;
599 }
600
601 if (itype->bit_size < bits_in_pointer)
602 index = cast_to(index, ssize_t_ctype);
603
604 if (multiply > 1) {
605 struct expression *val = alloc_expression(expr->pos, EXPR_VALUE);
606 struct expression *mul = alloc_expression(expr->pos, EXPR_BINOP);
607
608 val->ctype = ssize_t_ctype;
609 val->value = multiply;
610
611 mul->op = '*';
612 mul->ctype = ssize_t_ctype;
613 mul->left = index;
614 mul->right = val;
615 index = mul;
616 }
617
618 expr->right = index;
619 return ctype;
620 }
621
622 const char * type_difference(struct symbol *target, struct symbol *source,
623 unsigned long target_mod_ignore, unsigned long source_mod_ignore)
624 {
625 for (;;) {
626 unsigned long mod1, mod2, diff;
627 unsigned long as1, as2;
628 int type1, type2;
629 struct symbol *base1, *base2;
630
631 if (target == source)
632 break;
633 if (!target || !source)
634 return "different types";
635 /*
636 * Peel of per-node information.
637 * FIXME! Check alignment and context too here!
638 */
639 mod1 = target->ctype.modifiers;
640 as1 = target->ctype.as;
641 mod2 = source->ctype.modifiers;
642 as2 = source->ctype.as;
643 if (target->type == SYM_NODE) {
644 target = target->ctype.base_type;
645 if (!target)
646 return "bad types";
647 if (target->type == SYM_PTR) {
648 mod1 = 0;
649 as1 = 0;
650 }
651 mod1 |= target->ctype.modifiers;
652 as1 |= target->ctype.as;
653 }
654 if (source->type == SYM_NODE) {
655 source = source->ctype.base_type;
656 if (!source)
657 return "bad types";
658 if (source->type == SYM_PTR) {
659 mod2 = 0;
660 as2 = 0;
661 }
662 mod2 |= source->ctype.modifiers;
663 as2 |= source->ctype.as;
664 }
665 if (target->type == SYM_ENUM) {
666 target = target->ctype.base_type;
667 if (!target)
668 return "bad types";
669 }
670 if (source->type == SYM_ENUM) {
671 source = source->ctype.base_type;
672 if (!source)
673 return "bad types";
674 }
675
676 if (target == source)
677 break;
678 if (!target || !source)
679 return "different types";
680
681 type1 = target->type;
682 base1 = target->ctype.base_type;
683
684 type2 = source->type;
685 base2 = source->ctype.base_type;
686
687 /*
688 * Pointers to functions compare as the function itself
689 */
690 if (type1 == SYM_PTR && base1) {
691 base1 = examine_symbol_type(base1);
692 switch (base1->type) {
693 case SYM_FN:
694 type1 = SYM_FN;
695 target = base1;
696 base1 = base1->ctype.base_type;
697 default:
698 /* nothing */;
699 }
700 }
701 if (type2 == SYM_PTR && base2) {
702 base2 = examine_symbol_type(base2);
703 switch (base2->type) {
704 case SYM_FN:
705 type2 = SYM_FN;
706 source = base2;
707 base2 = base2->ctype.base_type;
708 default:
709 /* nothing */;
710 }
711 }
712
713 /* Arrays degenerate to pointers for type comparisons */
714 type1 = (type1 == SYM_ARRAY) ? SYM_PTR : type1;
715 type2 = (type2 == SYM_ARRAY) ? SYM_PTR : type2;
716
717 if (type1 != type2 || type1 == SYM_RESTRICT)
718 return "different base types";
719
720 /* Must be same address space to be comparable */
721 if (Waddress_space && as1 != as2)
722 return "different address spaces";
723
724 /* Ignore differences in storage types or addressability */
725 diff = (mod1 ^ mod2) & ~MOD_IGNORE;
726 diff &= (mod1 & ~target_mod_ignore) | (mod2 & ~source_mod_ignore);
727 if (diff) {
728 if (diff & MOD_SIZE)
729 return "different type sizes";
730 if (diff & ~MOD_SIGNEDNESS)
731 return "different modifiers";
732
733 /* Differs in signedness only.. */
734 if (Wtypesign) {
735 /*
736 * Warn if both are explicitly signed ("unsigned" is obviously
737 * always explicit, and since we know one of them has to be
738 * unsigned, we check if the signed one was explicit).
739 */
740 if ((mod1 | mod2) & MOD_EXPLICITLY_SIGNED)
741 return "different explicit signedness";
742
743 /*
744 * "char" matches both "unsigned char" and "signed char",
745 * so if the explicit test didn't trigger, then we should
746 * not warn about a char.
747 */
748 if (!(mod1 & MOD_CHAR))
749 return "different signedness";
750 }
751 }
752
753 if (type1 == SYM_FN) {
754 int i;
755 struct symbol *arg1, *arg2;
756 if (base1->variadic != base2->variadic)
757 return "incompatible variadic arguments";
758 PREPARE_PTR_LIST(target->arguments, arg1);
759 PREPARE_PTR_LIST(source->arguments, arg2);
760 i = 1;
761 for (;;) {
762 const char *diffstr;
763 diffstr = type_difference(arg1, arg2, 0, 0);
764 if (diffstr) {
765 static char argdiff[80];
766 sprintf(argdiff, "incompatible argument %d (%s)", i, diffstr);
767 return argdiff;
768 }
769 if (!arg1)
770 break;
771 NEXT_PTR_LIST(arg1);
772 NEXT_PTR_LIST(arg2);
773 i++;
774 }
775 FINISH_PTR_LIST(arg2);
776 FINISH_PTR_LIST(arg1);
777 }
778
779 target = base1;
780 source = base2;
781 }
782 return NULL;
783 }
784
785 static int is_null_ptr(struct expression *expr)
786 {
787 if (expr->type != EXPR_VALUE || expr->value)
788 return 0;
789 if (Wnon_pointer_null && !is_ptr_type(expr->ctype))
790 warning(expr->pos, "Using plain integer as NULL pointer");
791 return 1;
792 }
793
794 /*
795 * Ignore differences in "volatile" and "const"ness when
796 * subtracting pointers
797 */
798 #define MOD_IGN (MOD_VOLATILE | MOD_CONST)
799
800 static struct symbol *evaluate_ptr_sub(struct expression *expr)
801 {
802 const char *typediff;
803 struct symbol *ctype;
804 struct symbol *ltype, *rtype;
805 struct expression *l = expr->left;
806 struct expression *r = expr->right;
807
808 ltype = degenerate(l);
809 rtype = degenerate(r);
810
811 ctype = ltype;
812 typediff = type_difference(ltype, rtype, ~MOD_SIZE, ~MOD_SIZE);
813 if (typediff)
814 expression_error(expr, "subtraction of different types can't work (%s)", typediff);
815 examine_symbol_type(ctype);
816
817 /* Figure out the base type we point to */
818 if (ctype->type == SYM_NODE)
819 ctype = ctype->ctype.base_type;
820 if (ctype->type != SYM_PTR && ctype->type != SYM_ARRAY) {
821 expression_error(expr, "subtraction of functions? Share your drugs");
822 return NULL;
823 }
824 ctype = get_base_type(ctype);
825
826 expr->ctype = ssize_t_ctype;
827 if (ctype->bit_size > bits_in_char) {
828 struct expression *sub = alloc_expression(expr->pos, EXPR_BINOP);
829 struct expression *div = expr;
830 struct expression *val = alloc_expression(expr->pos, EXPR_VALUE);
831 unsigned long value = ctype->bit_size >> 3;
832
833 val->ctype = size_t_ctype;
834 val->value = value;
835
836 if (value & (value-1)) {
837 if (Wptr_subtraction_blows)
838 warning(expr->pos, "potentially expensive pointer subtraction");
839 }
840
841 sub->op = '-';
842 sub->ctype = ssize_t_ctype;
843 sub->left = l;
844 sub->right = r;
845
846 div->op = '/';
847 div->left = sub;
848 div->right = val;
849 }
850
851 return ssize_t_ctype;
852 }
853
854 #define is_safe_type(type) ((type)->ctype.modifiers & MOD_SAFE)
855
856 static struct symbol *evaluate_conditional(struct expression *expr, int iterator)
857 {
858 struct symbol *ctype;
859
860 if (!expr)
861 return NULL;
862
863 if (!iterator && expr->type == EXPR_ASSIGNMENT && expr->op == '=')
864 warning(expr->pos, "assignment expression in conditional");
865
866 ctype = evaluate_expression(expr);
867 if (ctype) {
868 if (is_safe_type(ctype))
869 warning(expr->pos, "testing a 'safe expression'");
870 }
871
872 return ctype;
873 }
874
875 static struct symbol *evaluate_logical(struct expression *expr)
876 {
877 if (!evaluate_conditional(expr->left, 0))
878 return NULL;
879 if (!evaluate_conditional(expr->right, 0))
880 return NULL;
881
882 expr->ctype = &bool_ctype;
883 return &bool_ctype;
884 }
885
886 static struct symbol *evaluate_binop(struct expression *expr)
887 {
888 struct symbol *ltype, *rtype, *ctype;
889 int lclass = classify_type(expr->left->ctype, &ltype);
890 int rclass = classify_type(expr->right->ctype, &rtype);
891 int op = expr->op;
892
893 /* number op number */
894 if (lclass & rclass & TYPE_NUM) {
895 if ((lclass | rclass) & TYPE_FLOAT) {
896 switch (op) {
897 case '+': case '-': case '*': case '/':
898 break;
899 default:
900 return bad_expr_type(expr);
901 }
902 }
903
904 if (op == SPECIAL_LEFTSHIFT || op == SPECIAL_RIGHTSHIFT) {
905 // shifts do integer promotions, but that's it.
906 unrestrict(expr->left, lclass, &ltype);
907 unrestrict(expr->right, rclass, &rtype);
908 ctype = ltype = integer_promotion(ltype);
909 rtype = integer_promotion(rtype);
910 } else {
911 // The rest do usual conversions
912 ltype = usual_conversions(op, expr->left, expr->right,
913 lclass, rclass, ltype, rtype);
914 ctype = rtype = ltype;
915 }
916
917 expr->left = cast_to(expr->left, ltype);
918 expr->right = cast_to(expr->right, rtype);
919 expr->ctype = ctype;
920 return ctype;
921 }
922
923 /* pointer (+|-) integer */
924 if (lclass & TYPE_PTR && is_int(rclass) && (op == '+' || op == '-')) {
925 unrestrict(expr->right, rclass, &rtype);
926 return evaluate_ptr_add(expr, degenerate(expr->left), rtype);
927 }
928
929 /* integer + pointer */
930 if (rclass & TYPE_PTR && is_int(lclass) && op == '+') {
931 struct expression *index = expr->left;
932 unrestrict(index, lclass, &ltype);
933 expr->left = expr->right;
934 expr->right = index;
935 return evaluate_ptr_add(expr, degenerate(expr->left), ltype);
936 }
937
938 /* pointer - pointer */
939 if (lclass & rclass & TYPE_PTR && expr->op == '-')
940 return evaluate_ptr_sub(expr);
941
942 return bad_expr_type(expr);
943 }
944
945 static struct symbol *evaluate_comma(struct expression *expr)
946 {
947 expr->ctype = expr->right->ctype;
948 return expr->ctype;
949 }
950
951 static int modify_for_unsigned(int op)
952 {
953 if (op == '<')
954 op = SPECIAL_UNSIGNED_LT;
955 else if (op == '>')
956 op = SPECIAL_UNSIGNED_GT;
957 else if (op == SPECIAL_LTE)
958 op = SPECIAL_UNSIGNED_LTE;
959 else if (op == SPECIAL_GTE)
960 op = SPECIAL_UNSIGNED_GTE;
961 return op;
962 }
963
964 static struct symbol *evaluate_compare(struct expression *expr)
965 {
966 struct expression *left = expr->left, *right = expr->right;
967 struct symbol *ltype = left->ctype, *rtype = right->ctype;
968 struct symbol *ctype;
969 int lclass, rclass;
970
971 /* Type types? */
972 if (is_type_type(ltype) && is_type_type(rtype))
973 goto OK;
974
975 if (is_safe_type(ltype) || is_safe_type(rtype))
976 warning(expr->pos, "testing a 'safe expression'");
977
978 lclass = classify_type(ltype, &ltype);
979 rclass = classify_type(rtype, &rtype);
980
981 /* Pointer types? */
982 if ((lclass | rclass) & TYPE_PTR) {
983 // FIXME! Check the types for compatibility
984 expr->op = modify_for_unsigned(expr->op);
985 goto OK;
986 }
987
988 /* Both should be numbers */
989 if (!(lclass & rclass & TYPE_NUM))
990 return bad_expr_type(expr);
991
992 ctype = usual_conversions(expr->op, expr->left, expr->right,
993 lclass, rclass, ltype, rtype);
994 expr->left = cast_to(expr->left, ctype);
995 expr->right = cast_to(expr->right, ctype);
996 if (ctype->ctype.modifiers & MOD_UNSIGNED)
997 expr->op = modify_for_unsigned(expr->op);
998
999 OK:
1000 expr->ctype = &bool_ctype;
1001 return &bool_ctype;
1002 }
1003
1004 /*
1005 * FIXME!! This should do casts, array degeneration etc..
1006 */
1007 static struct symbol *compatible_ptr_type(struct expression *left, struct expression *right)
1008 {
1009 struct symbol *ltype = left->ctype, *rtype = right->ctype;
1010
1011 if (ltype->type == SYM_NODE)
1012 ltype = ltype->ctype.base_type;
1013
1014 if (rtype->type == SYM_NODE)
1015 rtype = rtype->ctype.base_type;
1016
1017 if (ltype->type == SYM_PTR) {
1018 if (is_null_ptr(right) || rtype->ctype.base_type == &void_ctype)
1019 return ltype;
1020 }
1021
1022 if (rtype->type == SYM_PTR) {
1023 if (is_null_ptr(left) || ltype->ctype.base_type == &void_ctype)
1024 return rtype;
1025 }
1026 return NULL;
1027 }
1028
1029 /*
1030 * NOTE! The degenerate case of "x ? : y", where we don't
1031 * have a true case, this will possibly promote "x" to the
1032 * same type as "y", and thus _change_ the conditional
1033 * test in the expression. But since promotion is "safe"
1034 * for testing, that's OK.
1035 */
1036 static struct symbol *evaluate_conditional_expression(struct expression *expr)
1037 {
1038 struct expression **true;
1039 struct symbol *ctype, *ltype, *rtype;
1040 int lclass, rclass;
1041 const char * typediff;
1042
1043 if (!evaluate_conditional(expr->conditional, 0))
1044 return NULL;
1045 if (!evaluate_expression(expr->cond_false))
1046 return NULL;
1047
1048 ctype = degenerate(expr->conditional);
1049 rtype = degenerate(expr->cond_false);
1050
1051 true = &expr->conditional;
1052 ltype = ctype;
1053 if (expr->cond_true) {
1054 if (!evaluate_expression(expr->cond_true))
1055 return NULL;
1056 ltype = degenerate(expr->cond_true);
1057 true = &expr->cond_true;
1058 }
1059
1060 lclass = classify_type(ltype, &ltype);
1061 rclass = classify_type(rtype, &rtype);
1062 if (lclass & rclass & TYPE_NUM) {
1063 ctype = usual_conversions('?', *true, expr->cond_false,
1064 lclass, rclass, ltype, rtype);
1065 *true = cast_to(*true, ctype);
1066 expr->cond_false = cast_to(expr->cond_false, ctype);
1067 goto out;
1068 }
1069 ctype = compatible_ptr_type(*true, expr->cond_false);
1070 if (ctype)
1071 goto out;
1072 ctype = ltype;
1073 typediff = type_difference(ltype, rtype, MOD_IGN, MOD_IGN);
1074 if (!typediff)
1075 goto out;
1076 expression_error(expr, "incompatible types in conditional expression (%s)", typediff);
1077 return NULL;
1078
1079 out:
1080 expr->ctype = ctype;
1081 return ctype;
1082 }
1083
1084 /* FP assignments can not do modulo or bit operations */
1085 static int compatible_float_op(int op)
1086 {
1087 return op == SPECIAL_ADD_ASSIGN ||
1088 op == SPECIAL_SUB_ASSIGN ||
1089 op == SPECIAL_MUL_ASSIGN ||
1090 op == SPECIAL_DIV_ASSIGN;
1091 }
1092
1093 static int evaluate_assign_op(struct expression *expr)
1094 {
1095 struct symbol *target = expr->left->ctype;
1096 struct symbol *source = expr->right->ctype;
1097 struct symbol *t, *s;
1098 int tclass = classify_type(target, &t);
1099 int sclass = classify_type(source, &s);
1100 int op = expr->op;
1101
1102 if (tclass & sclass & TYPE_NUM) {
1103 if (tclass & TYPE_FLOAT && !compatible_float_op(op)) {
1104 expression_error(expr, "invalid assignment");
1105 return 0;
1106 }
1107 if (tclass & TYPE_RESTRICT) {
1108 if (!restricted_binop(op, t)) {
1109 expression_error(expr, "bad restricted assignment");
1110 return 0;
1111 }
1112 /* allowed assignments unfoul */
1113 if (sclass & TYPE_FOULED && s->ctype.base_type == t)
1114 goto Cast;
1115 if (!restricted_value(expr->right, t))
1116 return 1;
1117 } else if (!(sclass & TYPE_RESTRICT))
1118 goto Cast;
1119 /* source and target would better be identical restricted */
1120 if (t == s)
1121 return 1;
1122 warning(expr->pos, "invalid restricted assignment");
1123 expr->right = cast_to(expr->right, target);
1124 return 0;
1125 }
1126 if (tclass & TYPE_PTR && is_int(sclass)) {
1127 if (op == SPECIAL_ADD_ASSIGN || op == SPECIAL_SUB_ASSIGN) {
1128 unrestrict(expr->right, sclass, &s);
1129 evaluate_ptr_add(expr, target, s);
1130 return 1;
1131 }
1132 expression_error(expr, "invalid pointer assignment");
1133 return 0;
1134 }
1135
1136 expression_error(expr, "invalid assignment");
1137 return 0;
1138
1139 Cast:
1140 expr->right = cast_to(expr->right, target);
1141 return 1;
1142 }
1143
1144 static int compatible_assignment_types(struct expression *expr, struct symbol *target,
1145 struct expression **rp, const char *where)
1146 {
1147 const char *typediff;
1148 struct symbol *source = degenerate(*rp);
1149 struct symbol *t, *s;
1150 int tclass = classify_type(target, &t);
1151 int sclass = classify_type(source, &s);
1152
1153 if (tclass & sclass & TYPE_NUM) {
1154 if (tclass & TYPE_RESTRICT) {
1155 /* allowed assignments unfoul */
1156 if (sclass & TYPE_FOULED && s->ctype.base_type == t)
1157 goto Cast;
1158 if (!restricted_value(*rp, target))
1159 return 1;
1160 } else if (!(sclass & TYPE_RESTRICT))
1161 goto Cast;
1162 }
1163
1164 /* It's OK if the target is more volatile or const than the source */
1165 typediff = type_difference(target, source, MOD_VOLATILE | MOD_CONST, 0);
1166 if (!typediff)
1167 return 1;
1168
1169 /* Pointer destination? */
1170 if (tclass & TYPE_PTR) {
1171 struct expression *right = *rp;
1172 int source_as;
1173 int target_as;
1174
1175 // NULL pointer is always OK
1176 if (is_null_ptr(right))
1177 goto Cast;
1178
1179 /* "void *" matches anything as long as the address space is OK */
1180 target_as = t->ctype.as | target->ctype.as;
1181 source_as = s->ctype.as | source->ctype.as;
1182 if (source_as == target_as && (s->type == SYM_PTR || s->type == SYM_ARRAY)) {
1183 s = get_base_type(s);
1184 t = get_base_type(t);
1185 if (s == &void_ctype || t == &void_ctype)
1186 goto Cast;
1187 }
1188 }
1189
1190 warning(expr->pos, "incorrect type in %s (%s)", where, typediff);
1191 info(expr->pos, " expected %s", show_typename(target));
1192 info(expr->pos, " got %s", show_typename(source));
1193 *rp = cast_to(*rp, target);
1194 return 0;
1195 Cast:
1196 *rp = cast_to(*rp, target);
1197 return 1;
1198 }
1199
1200 static void mark_assigned(struct expression *expr)
1201 {
1202 struct symbol *sym;
1203
1204 if (!expr)
1205 return;
1206 switch (expr->type) {
1207 case EXPR_SYMBOL:
1208 sym = expr->symbol;
1209 if (!sym)
1210 return;
1211 if (sym->type != SYM_NODE)
1212 return;
1213 sym->ctype.modifiers |= MOD_ASSIGNED;
1214 return;
1215
1216 case EXPR_BINOP:
1217 mark_assigned(expr->left);
1218 mark_assigned(expr->right);
1219 return;
1220 case EXPR_CAST:
1221 mark_assigned(expr->cast_expression);
1222 return;
1223 case EXPR_SLICE:
1224 mark_assigned(expr->base);
1225 return;
1226 default:
1227 /* Hmm? */
1228 return;
1229 }
1230 }
1231
1232 static void evaluate_assign_to(struct expression *left, struct symbol *type)
1233 {
1234 if (type->ctype.modifiers & MOD_CONST)
1235 expression_error(left, "assignment to const expression");
1236
1237 /* We know left is an lvalue, so it's a "preop-*" */
1238 mark_assigned(left->unop);
1239 }
1240
1241 static struct symbol *evaluate_assignment(struct expression *expr)
1242 {
1243 struct expression *left = expr->left;
1244 struct expression *where = expr;
1245 struct symbol *ltype;
1246
1247 if (!lvalue_expression(left)) {
1248 expression_error(expr, "not an lvalue");
1249 return NULL;
1250 }
1251
1252 ltype = left->ctype;
1253
1254 if (expr->op != '=') {
1255 if (!evaluate_assign_op(expr))
1256 return NULL;
1257 } else {
1258 if (!compatible_assignment_types(where, ltype, &expr->right, "assignment"))
1259 return NULL;
1260 }
1261
1262 evaluate_assign_to(left, ltype);
1263
1264 expr->ctype = ltype;
1265 return ltype;
1266 }
1267
1268 static void examine_fn_arguments(struct symbol *fn)
1269 {
1270 struct symbol *s;
1271
1272 FOR_EACH_PTR(fn->arguments, s) {
1273 struct symbol *arg = evaluate_symbol(s);
1274 /* Array/function arguments silently degenerate into pointers */
1275 if (arg) {
1276 struct symbol *ptr;
1277 switch(arg->type) {
1278 case SYM_ARRAY:
1279 case SYM_FN:
1280 ptr = alloc_symbol(s->pos, SYM_PTR);
1281 if (arg->type == SYM_ARRAY)
1282 ptr->ctype = arg->ctype;
1283 else
1284 ptr->ctype.base_type = arg;
1285 ptr->ctype.as |= s->ctype.as;
1286 ptr->ctype.modifiers |= s->ctype.modifiers & MOD_PTRINHERIT;
1287
1288 s->ctype.base_type = ptr;
1289 s->ctype.as = 0;
1290 s->ctype.modifiers &= ~MOD_PTRINHERIT;
1291 s->bit_size = 0;
1292 s->examined = 0;
1293 examine_symbol_type(s);
1294 break;
1295 default:
1296 /* nothing */
1297 break;
1298 }
1299 }
1300 } END_FOR_EACH_PTR(s);
1301 }
1302
1303 static struct symbol *convert_to_as_mod(struct symbol *sym, int as, int mod)
1304 {
1305 /* Take the modifiers of the pointer, and apply them to the member */
1306 mod |= sym->ctype.modifiers;
1307 if (sym->ctype.as != as || sym->ctype.modifiers != mod) {
1308 struct symbol *newsym = alloc_symbol(sym->pos, SYM_NODE);
1309 *newsym = *sym;
1310 newsym->ctype.as = as;
1311 newsym->ctype.modifiers = mod;
1312 sym = newsym;
1313 }
1314 return sym;
1315 }
1316
1317 static struct symbol *create_pointer(struct expression *expr, struct symbol *sym, int degenerate)
1318 {
1319 struct symbol *node = alloc_symbol(expr->pos, SYM_NODE);
1320 struct symbol *ptr = alloc_symbol(expr->pos, SYM_PTR);
1321
1322 node->ctype.base_type = ptr;
1323 ptr->bit_size = bits_in_pointer;
1324 ptr->ctype.alignment = pointer_alignment;
1325
1326 node->bit_size = bits_in_pointer;
1327 node->ctype.alignment = pointer_alignment;
1328
1329 access_symbol(sym);
1330 if (sym->ctype.modifiers & MOD_REGISTER) {
1331 warning(expr->pos, "taking address of 'register' variable '%s'", show_ident(sym->ident));
1332 sym->ctype.modifiers &= ~MOD_REGISTER;
1333 }
1334 if (sym->type == SYM_NODE) {
1335 ptr->ctype.as |= sym->ctype.as;
1336 ptr->ctype.modifiers |= sym->ctype.modifiers & MOD_PTRINHERIT;
1337 sym = sym->ctype.base_type;
1338 }
1339 if (degenerate && sym->type == SYM_ARRAY) {
1340 ptr->ctype.as |= sym->ctype.as;
1341 ptr->ctype.modifiers |= sym->ctype.modifiers & MOD_PTRINHERIT;
1342 sym = sym->ctype.base_type;
1343 }
1344 ptr->ctype.base_type = sym;
1345
1346 return node;
1347 }
1348
1349 /* Arrays degenerate into pointers on pointer arithmetic */
1350 static struct symbol *degenerate(struct expression *expr)
1351 {
1352 struct symbol *ctype, *base;
1353
1354 if (!expr)
1355 return NULL;
1356 ctype = expr->ctype;
1357 if (!ctype)
1358 return NULL;
1359 base = examine_symbol_type(ctype);
1360 if (ctype->type == SYM_NODE)
1361 base = ctype->ctype.base_type;
1362 /*
1363 * Arrays degenerate into pointers to the entries, while
1364 * functions degenerate into pointers to themselves.
1365 * If array was part of non-lvalue compound, we create a copy
1366 * of that compound first and then act as if we were dealing with
1367 * the corresponding field in there.
1368 */
1369 switch (base->type) {
1370 case SYM_ARRAY:
1371 if (expr->type == EXPR_SLICE) {
1372 struct symbol *a = alloc_symbol(expr->pos, SYM_NODE);
1373 struct expression *e0, *e1, *e2, *e3, *e4;
1374
1375 a->ctype.base_type = expr->base->ctype;
1376 a->bit_size = expr->base->ctype->bit_size;
1377 a->array_size = expr->base->ctype->array_size;
1378
1379 e0 = alloc_expression(expr->pos, EXPR_SYMBOL);
1380 e0->symbol = a;
1381 e0->ctype = &lazy_ptr_ctype;
1382
1383 e1 = alloc_expression(expr->pos, EXPR_PREOP);
1384 e1->unop = e0;
1385 e1->op = '*';
1386 e1->ctype = expr->base->ctype; /* XXX */
1387
1388 e2 = alloc_expression(expr->pos, EXPR_ASSIGNMENT);
1389 e2->left = e1;
1390 e2->right = expr->base;
1391 e2->op = '=';
1392 e2->ctype = expr->base->ctype;
1393
1394 if (expr->r_bitpos) {
1395 e3 = alloc_expression(expr->pos, EXPR_BINOP);
1396 e3->op = '+';
1397 e3->left = e0;
1398 e3->right = alloc_const_expression(expr->pos,
1399 expr->r_bitpos >> 3);
1400 e3->ctype = &lazy_ptr_ctype;
1401 } else {
1402 e3 = e0;
1403 }
1404
1405 e4 = alloc_expression(expr->pos, EXPR_COMMA);
1406 e4->left = e2;
1407 e4->right = e3;
1408 e4->ctype = &lazy_ptr_ctype;
1409
1410 expr->unop = e4;
1411 expr->type = EXPR_PREOP;
1412 expr->op = '*';
1413 }
1414 case SYM_FN:
1415 if (expr->op != '*' || expr->type != EXPR_PREOP) {
1416 expression_error(expr, "strange non-value function or array");
1417 return &bad_ctype;
1418 }
1419 *expr = *expr->unop;
1420 ctype = create_pointer(expr, ctype, 1);
1421 expr->ctype = ctype;
1422 default:
1423 /* nothing */;
1424 }
1425 return ctype;
1426 }
1427
1428 static struct symbol *evaluate_addressof(struct expression *expr)
1429 {
1430 struct expression *op = expr->unop;
1431 struct symbol *ctype;
1432
1433 if (op->op != '*' || op->type != EXPR_PREOP) {
1434 expression_error(expr, "not addressable");
1435 return NULL;
1436 }
1437 ctype = op->ctype;
1438 *expr = *op->unop;
1439
1440 if (expr->type == EXPR_SYMBOL) {
1441 struct symbol *sym = expr->symbol;
1442 sym->ctype.modifiers |= MOD_ADDRESSABLE;
1443 }
1444
1445 /*
1446 * symbol expression evaluation is lazy about the type
1447 * of the sub-expression, so we may have to generate
1448 * the type here if so..
1449 */
1450 if (expr->ctype == &lazy_ptr_ctype) {
1451 ctype = create_pointer(expr, ctype, 0);
1452 expr->ctype = ctype;
1453 }
1454 return expr->ctype;
1455 }
1456
1457
1458 static struct symbol *evaluate_dereference(struct expression *expr)
1459 {
1460 struct expression *op = expr->unop;
1461 struct symbol *ctype = op->ctype, *node, *target;
1462
1463 /* Simplify: *&(expr) => (expr) */
1464 if (op->type == EXPR_PREOP && op->op == '&') {
1465 *expr = *op->unop;
1466 return expr->ctype;
1467 }
1468
1469 /* Dereferencing a node drops all the node information. */
1470 if (ctype->type == SYM_NODE)
1471 ctype = ctype->ctype.base_type;
1472
1473 node = alloc_symbol(expr->pos, SYM_NODE);
1474 target = ctype->ctype.base_type;
1475
1476 switch (ctype->type) {
1477 default:
1478 expression_error(expr, "cannot dereference this type");
1479 return NULL;
1480 case SYM_PTR:
1481 node->ctype.modifiers = target->ctype.modifiers & MOD_SPECIFIER;
1482 merge_type(node, ctype);
1483 break;
1484
1485 case SYM_ARRAY:
1486 if (!lvalue_expression(op)) {
1487 expression_error(op, "non-lvalue array??");
1488 return NULL;
1489 }
1490
1491 /* Do the implied "addressof" on the array */
1492 *op = *op->unop;
1493
1494 /*
1495 * When an array is dereferenced, we need to pick
1496 * up the attributes of the original node too..
1497 */
1498 merge_type(node, op->ctype);
1499 merge_type(node, ctype);
1500 break;
1501 }
1502
1503 node->bit_size = target->bit_size;
1504 node->array_size = target->array_size;
1505
1506 expr->ctype = node;
1507 return node;
1508 }
1509
1510 /*
1511 * Unary post-ops: x++ and x--
1512 */
1513 static struct symbol *evaluate_postop(struct expression *expr)
1514 {
1515 struct expression *op = expr->unop;
1516 struct symbol *ctype = op->ctype;
1517
1518 if (!lvalue_expression(expr->unop)) {
1519 expression_error(expr, "need lvalue expression for ++/--");
1520 return NULL;
1521 }
1522 if (is_restricted_type(ctype) && restricted_unop(expr->op, &ctype)) {
1523 expression_error(expr, "bad operation on restricted");
1524 return NULL;
1525 } else if (is_fouled_type(ctype) && restricted_unop(expr->op, &ctype)) {
1526 expression_error(expr, "bad operation on restricted");
1527 return NULL;
1528 }
1529
1530 evaluate_assign_to(op, ctype);
1531
1532 expr->ctype = ctype;
1533 expr->op_value = 1;
1534 if (is_ptr_type(ctype))
1535 expr->op_value = ptr_object_size(ctype) >> 3;
1536
1537 return ctype;
1538 }
1539
1540 static struct symbol *evaluate_sign(struct expression *expr)
1541 {
1542 struct symbol *ctype = expr->unop->ctype;
1543 if (is_int_type(ctype)) {
1544 struct symbol *rtype = rtype = integer_promotion(ctype);
1545 expr->unop = cast_to(expr->unop, rtype);
1546 ctype = rtype;
1547 } else if (is_float_type(ctype) && expr->op != '~') {
1548 /* no conversions needed */
1549 } else if (is_restricted_type(ctype) && !restricted_unop(expr->op, &ctype)) {
1550 /* no conversions needed */
1551 } else if (is_fouled_type(ctype) && !restricted_unop(expr->op, &ctype)) {
1552 /* no conversions needed */
1553 } else {
1554 return bad_expr_type(expr);
1555 }
1556 if (expr->op == '+')
1557 *expr = *expr->unop;
1558 expr->ctype = ctype;
1559 return ctype;
1560 }
1561
1562 static struct symbol *evaluate_preop(struct expression *expr)
1563 {
1564 struct symbol *ctype = expr->unop->ctype;
1565
1566 switch (expr->op) {
1567 case '(':
1568 *expr = *expr->unop;
1569 return ctype;
1570
1571 case '+':
1572 case '-':
1573 case '~':
1574 return evaluate_sign(expr);
1575
1576 case '*':
1577 return evaluate_dereference(expr);
1578
1579 case '&':
1580 return evaluate_addressof(expr);
1581
1582 case SPECIAL_INCREMENT:
1583 case SPECIAL_DECREMENT:
1584 /*
1585 * From a type evaluation standpoint the preops are
1586 * the same as the postops
1587 */
1588 return evaluate_postop(expr);
1589
1590 case '!':
1591 if (is_safe_type(ctype))
1592 warning(expr->pos, "testing a 'safe expression'");
1593 if (is_float_type(ctype)) {
1594 struct expression *arg = expr->unop;
1595 expr->type = EXPR_BINOP;
1596 expr->op = SPECIAL_EQUAL;
1597 expr->left = arg;
1598 expr->right = alloc_expression(expr->pos, EXPR_FVALUE);
1599 expr->right->ctype = ctype;
1600 expr->right->fvalue = 0;
1601 } else if (is_fouled_type(ctype)) {
1602 warning(expr->pos, "restricted degrades to integer");
1603 }
1604 ctype = &bool_ctype;
1605 break;
1606
1607 default:
1608 break;
1609 }
1610 expr->ctype = ctype;
1611 return &bool_ctype;
1612 }
1613
1614 static struct symbol *find_identifier(struct ident *ident, struct symbol_list *_list, int *offset)
1615 {
1616 struct ptr_list *head = (struct ptr_list *)_list;
1617 struct ptr_list *list = head;
1618
1619 if (!head)
1620 return NULL;
1621 do {
1622 int i;
1623 for (i = 0; i < list->nr; i++) {
1624 struct symbol *sym = (struct symbol *) list->list[i];
1625 if (sym->ident) {
1626 if (sym->ident != ident)
1627 continue;
1628 *offset = sym->offset;
1629 return sym;
1630 } else {
1631 struct symbol *ctype = sym->ctype.base_type;
1632 struct symbol *sub;
1633 if (!ctype)
1634 continue;
1635 if (ctype->type != SYM_UNION && ctype->type != SYM_STRUCT)
1636 continue;
1637 sub = find_identifier(ident, ctype->symbol_list, offset);
1638 if (!sub)
1639 continue;
1640 *offset += sym->offset;
1641 return sub;
1642 }
1643 }
1644 } while ((list = list->next) != head);
1645 return NULL;
1646 }
1647
1648 static struct expression *evaluate_offset(struct expression *expr, unsigned long offset)
1649 {
1650 struct expression *add;
1651
1652 /*
1653 * Create a new add-expression
1654 *
1655 * NOTE! Even if we just add zero, we need a new node
1656 * for the member pointer, since it has a different
1657 * type than the original pointer. We could make that
1658 * be just a cast, but the fact is, a node is a node,
1659 * so we might as well just do the "add zero" here.
1660 */
1661 add = alloc_expression(expr->pos, EXPR_BINOP);
1662 add->op = '+';
1663 add->left = expr;
1664 add->right = alloc_expression(expr->pos, EXPR_VALUE);
1665 add->right->ctype = &int_ctype;
1666 add->right->value = offset;
1667
1668 /*
1669 * The ctype of the pointer will be lazily evaluated if
1670 * we ever take the address of this member dereference..
1671 */
1672 add->ctype = &lazy_ptr_ctype;
1673 return add;
1674 }
1675
1676 /* structure/union dereference */
1677 static struct symbol *evaluate_member_dereference(struct expression *expr)
1678 {
1679 int offset;
1680 struct symbol *ctype, *member;
1681 struct expression *deref = expr->deref, *add;
1682 struct ident *ident = expr->member;
1683 unsigned int mod;
1684 int address_space;
1685
1686 if (!evaluate_expression(deref))
1687 return NULL;
1688 if (!ident) {
1689 expression_error(expr, "bad member name");
1690 return NULL;
1691 }
1692
1693 ctype = deref->ctype;
1694 address_space = ctype->ctype.as;
1695 mod = ctype->ctype.modifiers;
1696 if (ctype->type == SYM_NODE) {
1697 ctype = ctype->ctype.base_type;
1698 address_space |= ctype->ctype.as;
1699 mod |= ctype->ctype.modifiers;
1700 }
1701 if (!ctype || (ctype->type != SYM_STRUCT && ctype->type != SYM_UNION)) {
1702 expression_error(expr, "expected structure or union");
1703 return NULL;
1704 }
1705 examine_symbol_type(ctype);
1706 offset = 0;
1707 member = find_identifier(ident, ctype->symbol_list, &offset);
1708 if (!member) {
1709 const char *type = ctype->type == SYM_STRUCT ? "struct" : "union";
1710 const char *name = "<unnamed>";
1711 int namelen = 9;
1712 if (ctype->ident) {
1713 name = ctype->ident->name;
1714 namelen = ctype->ident->len;
1715 }
1716 if (ctype->symbol_list)
1717 expression_error(expr, "no member '%s' in %s %.*s",
1718 show_ident(ident), type, namelen, name);
1719 else
1720 expression_error(expr, "using member '%s' in "
1721 "incomplete %s %.*s", show_ident(ident),
1722 type, namelen, name);
1723 return NULL;
1724 }
1725
1726 /*
1727 * The member needs to take on the address space and modifiers of
1728 * the "parent" type.
1729 */
1730 member = convert_to_as_mod(member, address_space, mod);
1731 ctype = get_base_type(member);
1732
1733 if (!lvalue_expression(deref)) {
1734 if (deref->type != EXPR_SLICE) {
1735 expr->base = deref;
1736 expr->r_bitpos = 0;
1737 } else {
1738 expr->base = deref->base;
1739 expr->r_bitpos = deref->r_bitpos;
1740 }
1741 expr->r_bitpos += offset << 3;
1742 expr->type = EXPR_SLICE;
1743 expr->r_nrbits = member->bit_size;
1744 expr->r_bitpos += member->bit_offset;
1745 expr->ctype = member;
1746 return member;
1747 }
1748
1749 deref = deref->unop;
1750 expr->deref = deref;
1751
1752 add = evaluate_offset(deref, offset);
1753 expr->type = EXPR_PREOP;
1754 expr->op = '*';
1755 expr->unop = add;
1756
1757 expr->ctype = member;
1758 return member;
1759 }
1760
1761 static int is_promoted(struct expression *expr)
1762 {
1763 while (1) {
1764 switch (expr->type) {
1765 case EXPR_BINOP:
1766 case EXPR_SELECT:
1767 case EXPR_CONDITIONAL:
1768 return 1;
1769 case EXPR_COMMA:
1770 expr = expr->right;
1771 continue;
1772 case EXPR_PREOP:
1773 switch (expr->op) {
1774 case '(':
1775 expr = expr->unop;
1776 continue;
1777 case '+':
1778 case '-':
1779 case '~':
1780 return 1;
1781 default:
1782 return 0;
1783 }
1784 default:
1785 return 0;
1786 }
1787 }
1788 }
1789
1790
1791 static struct symbol *evaluate_cast(struct expression *);
1792
1793 static struct symbol *evaluate_type_information(struct expression *expr)
1794 {
1795 struct symbol *sym = expr->cast_type;
1796 if (!sym) {
1797 sym = evaluate_expression(expr->cast_expression);
1798 if (!sym)
1799 return NULL;
1800 /*
1801 * Expressions of restricted types will possibly get
1802 * promoted - check that here
1803 */
1804 if (is_restricted_type(sym)) {
1805 if (sym->bit_size < bits_in_int && is_promoted(expr))
1806 sym = &int_ctype;
1807 } else if (is_fouled_type(sym)) {
1808 sym = &int_ctype;
1809 }
1810 }
1811 examine_symbol_type(sym);
1812 if (is_bitfield_type(sym)) {
1813 expression_error(expr, "trying to examine bitfield type");
1814 return NULL;
1815 }
1816 return sym;
1817 }
1818
1819 static struct symbol *evaluate_sizeof(struct expression *expr)
1820 {
1821 struct symbol *type;
1822 int size;
1823
1824 type = evaluate_type_information(expr);
1825 if (!type)
1826 return NULL;
1827
1828 size = type->bit_size;
1829 if ((size < 0) || (size & 7))
1830 expression_error(expr, "cannot size expression");
1831 expr->type = EXPR_VALUE;
1832 expr->value = size >> 3;
1833 expr->ctype = size_t_ctype;
1834 return size_t_ctype;
1835 }
1836
1837 static struct symbol *evaluate_ptrsizeof(struct expression *expr)
1838 {
1839 struct symbol *type;
1840 int size;
1841
1842 type = evaluate_type_information(expr);
1843 if (!type)
1844 return NULL;
1845
1846 if (type->type == SYM_NODE)
1847 type = type->ctype.base_type;
1848 if (!type)
1849 return NULL;
1850 switch (type->type) {
1851 case SYM_ARRAY:
1852 break;
1853 case SYM_PTR:
1854 type = get_base_type(type);
1855 if (type)
1856 break;
1857 default:
1858 expression_error(expr, "expected pointer expression");
1859 return NULL;
1860 }
1861 size = type->bit_size;
1862 if (size & 7)
1863 size = 0;
1864 expr->type = EXPR_VALUE;
1865 expr->value = size >> 3;
1866 expr->ctype = size_t_ctype;
1867 return size_t_ctype;
1868 }
1869
1870 static struct symbol *evaluate_alignof(struct expression *expr)
1871 {
1872 struct symbol *type;
1873
1874 type = evaluate_type_information(expr);
1875 if (!type)
1876 return NULL;
1877
1878 expr->type = EXPR_VALUE;
1879 expr->value = type->ctype.alignment;
1880 expr->ctype = size_t_ctype;
1881 return size_t_ctype;
1882 }
1883
1884 static int evaluate_arguments(struct symbol *f, struct symbol *fn, struct expression_list *head)
1885 {
1886 struct expression *expr;
1887 struct symbol_list *argument_types = fn->arguments;
1888 struct symbol *argtype;
1889 int i = 1;
1890
1891 PREPARE_PTR_LIST(argument_types, argtype);
1892 FOR_EACH_PTR (head, expr) {
1893 struct expression **p = THIS_ADDRESS(expr);
1894 struct symbol *ctype, *target;
1895 ctype = evaluate_expression(expr);
1896
1897 if (!ctype)
1898 return 0;
1899
1900 target = argtype;
1901 if (!target) {
1902 struct symbol *type;
1903 int class = classify_type(ctype, &type);
1904 if (is_int(class)) {
1905 *p = cast_to(expr, integer_promotion(type));
1906 } else if (class & TYPE_FLOAT) {
1907 unsigned long mod = type->ctype.modifiers;
1908 if (!(mod & (MOD_LONG|MOD_LONGLONG)))
1909 *p = cast_to(expr, &double_ctype);
1910 } else if (class & TYPE_PTR) {
1911 degenerate(expr);
1912 }
1913 } else {
1914 static char where[30];
1915 examine_symbol_type(target);
1916 sprintf(where, "argument %d", i);
1917 compatible_assignment_types(expr, target, p, where);
1918 }
1919
1920 i++;
1921 NEXT_PTR_LIST(argtype);
1922 } END_FOR_EACH_PTR(expr);
1923 FINISH_PTR_LIST(argtype);
1924 return 1;
1925 }
1926
1927 static struct symbol *find_struct_ident(struct symbol *ctype, struct ident *ident)
1928 {
1929 struct symbol *sym;
1930
1931 FOR_EACH_PTR(ctype->symbol_list, sym) {
1932 if (sym->ident == ident)
1933 return sym;
1934 } END_FOR_EACH_PTR(sym);
1935 return NULL;
1936 }
1937
1938 static void convert_index(struct expression *e)
1939 {
1940 struct expression *child = e->idx_expression;
1941 unsigned from = e->idx_from;
1942 unsigned to = e->idx_to + 1;
1943 e->type = EXPR_POS;
1944 e->init_offset = from * (e->ctype->bit_size>>3);
1945 e->init_nr = to - from;
1946 e->init_expr = child;
1947 }
1948
1949 static void convert_ident(struct expression *e)
1950 {
1951 struct expression *child = e->ident_expression;
1952 struct symbol *sym = e->field;
1953 e->type = EXPR_POS;
1954 e->init_offset = sym->offset;
1955 e->init_nr = 1;
1956 e->init_expr = child;
1957 }
1958
1959 static void convert_designators(struct expression *e)
1960 {
1961 while (e) {
1962 if (e->type == EXPR_INDEX)
1963 convert_index(e);
1964 else if (e->type == EXPR_IDENTIFIER)
1965 convert_ident(e);
1966 else
1967 break;
1968 e = e->init_expr;
1969 }
1970 }
1971
1972 static void excess(struct expression *e, const char *s)
1973 {
1974 warning(e->pos, "excessive elements in %s initializer", s);
1975 }
1976
1977 /*
1978 * implicit designator for the first element
1979 */
1980 static struct expression *first_subobject(struct symbol *ctype, int class,
1981 struct expression **v)
1982 {
1983 struct expression *e = *v, *new;
1984
1985 if (ctype->type == SYM_NODE)
1986 ctype = ctype->ctype.base_type;
1987
1988 if (class & TYPE_PTR) { /* array */
1989 if (!ctype->bit_size)
1990 return NULL;
1991 new = alloc_expression(e->pos, EXPR_INDEX);
1992 new->idx_expression = e;
1993 new->ctype = ctype->ctype.base_type;
1994 } else {
1995 struct symbol *field, *p;
1996 PREPARE_PTR_LIST(ctype->symbol_list, p);
1997 while (p && !p->ident && is_bitfield_type(p))
1998 NEXT_PTR_LIST(p);
1999 field = p;
2000 FINISH_PTR_LIST(p);
2001 if (!field)
2002 return NULL;
2003 new = alloc_expression(e->pos, EXPR_IDENTIFIER);
2004 new->ident_expression = e;
2005 new->field = new->ctype = field;
2006 }
2007 *v = new;
2008 return new;
2009 }
2010
2011 /*
2012 * sanity-check explicit designators; return the innermost one or NULL
2013 * in case of error. Assign types.
2014 */
2015 static struct expression *check_designators(struct expression *e,
2016 struct symbol *ctype)
2017 {
2018 struct expression *last = NULL;
2019 const char *err;
2020 while (1) {
2021 if (ctype->type == SYM_NODE)
2022 ctype = ctype->ctype.base_type;
2023 if (e->type == EXPR_INDEX) {
2024 struct symbol *type;
2025 if (ctype->type != SYM_ARRAY) {
2026 err = "array index in non-array";
2027 break;
2028 }
2029 type = ctype->ctype.base_type;
2030 if (ctype->bit_size >= 0 && type->bit_size >= 0) {
2031 unsigned offset = e->idx_to * type->bit_size;
2032 if (offset >= ctype->bit_size) {
2033 err = "index out of bounds in";
2034 break;
2035 }
2036 }
2037 e->ctype = ctype = type;
2038 ctype = type;
2039 last = e;
2040 if (!e->idx_expression) {
2041 err = "invalid";
2042 break;
2043 }
2044 e = e->idx_expression;
2045 } else if (e->type == EXPR_IDENTIFIER) {
2046 if (ctype->type != SYM_STRUCT && ctype->type != SYM_UNION) {
2047 err = "field name not in struct or union";
2048 break;
2049 }
2050 ctype = find_struct_ident(ctype, e->expr_ident);
2051 if (!ctype) {
2052 err = "unknown field name in";
2053 break;
2054 }
2055 e->field = e->ctype = ctype;
2056 last = e;
2057 if (!e->ident_expression) {
2058 err = "invalid";
2059 break;
2060 }
2061 e = e->ident_expression;
2062 } else if (e->type == EXPR_POS) {
2063 err = "internal front-end error: EXPR_POS in";
2064 break;
2065 } else
2066 return last;
2067 }
2068 expression_error(e, "%s initializer", err);
2069 return NULL;
2070 }
2071
2072 /*
2073 * choose the next subobject to initialize.
2074 *
2075 * Get designators for next element, switch old ones to EXPR_POS.
2076 * Return the resulting expression or NULL if we'd run out of subobjects.
2077 * The innermost designator is returned in *v. Designators in old
2078 * are assumed to be already sanity-checked.
2079 */
2080 static struct expression *next_designators(struct expression *old,
2081 struct symbol *ctype,
2082 struct expression *e, struct expression **v)
2083 {
2084 struct expression *new = NULL;
2085
2086 if (!old)
2087 return NULL;
2088 if (old->type == EXPR_INDEX) {
2089 struct expression *copy;
2090 unsigned n;
2091
2092 copy = next_designators(old->idx_expression,
2093 old->ctype, e, v);
2094 if (!copy) {
2095 n = old->idx_to + 1;
2096 if (n * old->ctype->bit_size == ctype->bit_size) {
2097 convert_index(old);
2098 return NULL;
2099 }
2100 copy = e;
2101 *v = new = alloc_expression(e->pos, EXPR_INDEX);
2102 } else {
2103 n = old->idx_to;
2104 new = alloc_expression(e->pos, EXPR_INDEX);
2105 }
2106
2107 new->idx_from = new->idx_to = n;
2108 new->idx_expression = copy;
2109 new->ctype = old->ctype;
2110 convert_index(old);
2111 } else if (old->type == EXPR_IDENTIFIER) {
2112 struct expression *copy;
2113 struct symbol *field;
2114
2115 copy = next_designators(old->ident_expression,
2116 old->ctype, e, v);
2117 if (!copy) {
2118 field = old->field->next_subobject;
2119 if (!field) {
2120 convert_ident(old);
2121 return NULL;
2122 }
2123 copy = e;
2124 *v = new = alloc_expression(e->pos, EXPR_IDENTIFIER);
2125 } else {
2126 field = old->field;
2127 new = alloc_expression(e->pos, EXPR_IDENTIFIER);
2128 }
2129
2130 new->field = field;
2131 new->expr_ident = field->ident;
2132 new->ident_expression = copy;
2133 new->ctype = field;
2134 convert_ident(old);
2135 }
2136 return new;
2137 }
2138
2139 static int handle_simple_initializer(struct expression **ep, int nested,
2140 int class, struct symbol *ctype);
2141
2142 /*
2143 * deal with traversing subobjects [6.7.8(17,18,20)]
2144 */
2145 static void handle_list_initializer(struct expression *expr,
2146 int class, struct symbol *ctype)
2147 {
2148 struct expression *e, *last = NULL, *top = NULL, *next;
2149 int jumped = 0;
2150
2151 FOR_EACH_PTR(expr->expr_list, e) {
2152 struct expression **v;
2153 struct symbol *type;
2154 int lclass;
2155
2156 if (e->type != EXPR_INDEX && e->type != EXPR_IDENTIFIER) {
2157 if (!top) {
2158 top = e;
2159 last = first_subobject(ctype, class, &top);
2160 } else {
2161 last = next_designators(last, ctype, e, &top);
2162 }
2163 if (!last) {
2164 excess(e, class & TYPE_PTR ? "array" :
2165 "struct or union");
2166 DELETE_CURRENT_PTR(e);
2167 continue;
2168 }
2169 if (jumped) {
2170 warning(e->pos, "advancing past deep designator");
2171 jumped = 0;
2172 }
2173 REPLACE_CURRENT_PTR(e, last);
2174 } else {
2175 next = check_designators(e, ctype);
2176 if (!next) {
2177 DELETE_CURRENT_PTR(e);
2178 continue;
2179 }
2180 top = next;
2181 /* deeper than one designator? */
2182 jumped = top != e;
2183 convert_designators(last);
2184 last = e;
2185 }
2186
2187 found:
2188 lclass = classify_type(top->ctype, &type);
2189 if (top->type == EXPR_INDEX)
2190 v = &top->idx_expression;
2191 else
2192 v = &top->ident_expression;
2193
2194 if (handle_simple_initializer(v, 1, lclass, top->ctype))
2195 continue;
2196
2197 if (!(lclass & TYPE_COMPOUND)) {
2198 warning(e->pos, "bogus scalar initializer");
2199 DELETE_CURRENT_PTR(e);
2200 continue;
2201 }
2202
2203 next = first_subobject(type, lclass, v);
2204 if (next) {
2205 warning(e->pos, "missing braces around initializer");
2206 top = next;
2207 goto found;
2208 }
2209
2210 DELETE_CURRENT_PTR(e);
2211 excess(e, lclass & TYPE_PTR ? "array" : "struct or union");
2212
2213 } END_FOR_EACH_PTR(e);
2214
2215 convert_designators(last);
2216 expr->ctype = ctype;
2217 }
2218
2219 static int is_string_literal(struct expression **v)
2220 {
2221 struct expression *e = *v;
2222 while (e && e->type == EXPR_PREOP && e->op == '(')
2223 e = e->unop;
2224 if (!e || e->type != EXPR_STRING)
2225 return 0;
2226 if (e != *v && Wparen_string)
2227 warning(e->pos,
2228 "array initialized from parenthesized string constant");
2229 *v = e;
2230 return 1;
2231 }
2232
2233 /*
2234 * We want a normal expression, possibly in one layer of braces. Warn
2235 * if the latter happens inside a list (it's legal, but likely to be
2236 * an effect of screwup). In case of anything not legal, we are definitely
2237 * having an effect of screwup, so just fail and let the caller warn.
2238 */
2239 static struct expression *handle_scalar(struct expression *e, int nested)
2240 {
2241 struct expression *v = NULL, *p;
2242 int count = 0;
2243
2244 /* normal case */
2245 if (e->type != EXPR_INITIALIZER)
2246 return e;
2247
2248 FOR_EACH_PTR(e->expr_list, p) {
2249 if (!v)
2250 v = p;
2251 count++;
2252 } END_FOR_EACH_PTR(p);
2253 if (count != 1)
2254 return NULL;
2255 switch(v->type) {
2256 case EXPR_INITIALIZER:
2257 case EXPR_INDEX:
2258 case EXPR_IDENTIFIER:
2259 return NULL;
2260 default:
2261 break;
2262 }
2263 if (nested)
2264 warning(e->pos, "braces around scalar initializer");
2265 return v;
2266 }
2267
2268 /*
2269 * deal with the cases that don't care about subobjects:
2270 * scalar <- assignment expression, possibly in braces [6.7.8(11)]
2271 * character array <- string literal, possibly in braces [6.7.8(14)]
2272 * struct or union <- assignment expression of compatible type [6.7.8(13)]
2273 * compound type <- initializer list in braces [6.7.8(16)]
2274 * The last one punts to handle_list_initializer() which, in turn will call
2275 * us for individual elements of the list.
2276 *
2277 * We do not handle 6.7.8(15) (wide char array <- wide string literal) for
2278 * the lack of support of wide char stuff in general.
2279 *
2280 * One note: we need to take care not to evaluate a string literal until
2281 * we know that we *will* handle it right here. Otherwise we would screw
2282 * the cases like struct { struct {char s[10]; ...} ...} initialized with
2283 * { "string", ...} - we need to preserve that string literal recognizable
2284 * until we dig into the inner struct.
2285 */
2286 static int handle_simple_initializer(struct expression **ep, int nested,
2287 int class, struct symbol *ctype)
2288 {
2289 int is_string = is_string_type(ctype);
2290 struct expression *e = *ep, *p;
2291 struct symbol *type;
2292
2293 if (!e)
2294 return 0;
2295
2296 /* scalar */
2297 if (!(class & TYPE_COMPOUND)) {
2298 e = handle_scalar(e, nested);
2299 if (!e)
2300 return 0;
2301 *ep = e;
2302 if (!evaluate_expression(e))
2303 return 1;
2304 compatible_assignment_types(e, ctype, ep, "initializer");
2305 return 1;
2306 }
2307
2308 /*
2309 * sublist; either a string, or we dig in; the latter will deal with
2310 * pathologies, so we don't need anything fancy here.
2311 */
2312 if (e->type == EXPR_INITIALIZER) {
2313 if (is_string) {
2314 struct expression *v = NULL;
2315 int count = 0;
2316
2317 FOR_EACH_PTR(e->expr_list, p) {
2318 if (!v)
2319 v = p;
2320 count++;
2321 } END_FOR_EACH_PTR(p);
2322 if (count == 1 && is_string_literal(&v)) {
2323 *ep = e = v;
2324 goto String;
2325 }
2326 }
2327 handle_list_initializer(e, class, ctype);
2328 return 1;
2329 }
2330
2331 /* string */
2332 if (is_string_literal(&e)) {
2333 /* either we are doing array of char, or we'll have to dig in */
2334 if (is_string) {
2335 *ep = e;
2336 goto String;
2337 }
2338 return 0;
2339 }
2340 /* struct or union can be initialized by compatible */
2341 if (class != TYPE_COMPOUND)
2342 return 0;
2343 type = evaluate_expression(e);
2344 if (!type)
2345 return 0;
2346 if (ctype->type == SYM_NODE)
2347 ctype = ctype->ctype.base_type;
2348 if (type->type == SYM_NODE)
2349 type = type->ctype.base_type;
2350 if (ctype == type)
2351 return 1;
2352 return 0;
2353
2354 String:
2355 p = alloc_expression(e->pos, EXPR_STRING);
2356 *p = *e;
2357 type = evaluate_expression(p);
2358 if (ctype->bit_size != -1 &&
2359 ctype->bit_size + bits_in_char < type->bit_size) {
2360 warning(e->pos,
2361 "too long initializer-string for array of char");
2362 }
2363 *ep = p;
2364 return 1;
2365 }
2366
2367 static void evaluate_initializer(struct symbol *ctype, struct expression **ep)
2368 {
2369 struct symbol *type;
2370 int class = classify_type(ctype, &type);
2371 if (!handle_simple_initializer(ep, 0, class, ctype))
2372 expression_error(*ep, "invalid initializer");
2373 }
2374
2375 static int get_as(struct symbol *sym)
2376 {
2377 int as;
2378 unsigned long mod;
2379
2380 if (!sym)
2381 return 0;
2382 as = sym->ctype.as;
2383 mod = sym->ctype.modifiers;
2384 if (sym->type == SYM_NODE) {
2385 sym = sym->ctype.base_type;
2386 as |= sym->ctype.as;
2387 mod |= sym->ctype.modifiers;
2388 }
2389
2390 /*
2391 * At least for now, allow casting to a "unsigned long".
2392 * That's how we do things like pointer arithmetic and
2393 * store pointers to registers.
2394 */
2395 if (sym == &ulong_ctype)
2396 return -1;
2397
2398 if (sym && sym->type == SYM_PTR) {
2399 sym = get_base_type(sym);
2400 as |= sym->ctype.as;
2401 mod |= sym->ctype.modifiers;
2402 }
2403 if (mod & MOD_FORCE)
2404 return -1;
2405 return as;
2406 }
2407
2408 static void cast_to_as(struct expression *e, int as)
2409 {
2410 struct expression *v = e->cast_expression;
2411 struct symbol *type = v->ctype;
2412
2413 if (!Wcast_to_address_space)
2414 return;
2415
2416 if (v->type != EXPR_VALUE || v->value)
2417 goto out;
2418
2419 /* cast from constant 0 to pointer is OK */
2420 if (is_int_type(type))
2421 return;
2422
2423 if (type->type == SYM_NODE)
2424 type = type->ctype.base_type;
2425
2426 if (type->type == SYM_PTR && type->ctype.base_type == &void_ctype)
2427 return;
2428
2429 out:
2430 warning(e->pos, "cast adds address space to expression (<asn:%d>)", as);
2431 }
2432
2433 static struct symbol *evaluate_cast(struct expression *expr)
2434 {
2435 struct expression *target = expr->cast_expression;
2436 struct symbol *ctype;
2437 struct symbol *t1, *t2;
2438 int class1, class2;
2439 int as1, as2;
2440
2441 if (!target)
2442 return NULL;
2443
2444 /*
2445 * Special case: a cast can be followed by an
2446 * initializer, in which case we need to pass
2447 * the type value down to that initializer rather
2448 * than trying to evaluate it as an expression
2449 *
2450 * A more complex case is when the initializer is
2451 * dereferenced as part of a post-fix expression.
2452 * We need to produce an expression that can be dereferenced.
2453 */
2454 if (target->type == EXPR_INITIALIZER) {
2455 struct symbol *sym = expr->cast_type;
2456 struct expression *addr = alloc_expression(expr->pos, EXPR_SYMBOL);
2457
2458 sym->initializer = target;
2459 evaluate_symbol(sym);
2460
2461 addr->ctype = &lazy_ptr_ctype; /* Lazy eval */
2462 addr->symbol = sym;
2463
2464 expr->type = EXPR_PREOP;
2465 expr->op = '*';
2466 expr->unop = addr;
2467 expr->ctype = sym;
2468
2469 return sym;
2470 }
2471
2472 ctype = examine_symbol_type(expr->cast_type);
2473 expr->ctype = ctype;
2474 expr->cast_type = ctype;
2475
2476 evaluate_expression(target);
2477 degenerate(target);
2478
2479 class1 = classify_type(ctype, &t1);
2480 /*
2481 * You can always throw a value away by casting to
2482 * "void" - that's an implicit "force". Note that
2483 * the same is _not_ true of "void *".
2484 */
2485 if (t1 == &void_ctype)
2486 goto out;
2487
2488 if (class1 & TYPE_COMPOUND)
2489 warning(expr->pos, "cast to non-scalar");
2490
2491 t2 = target->ctype;
2492 if (!t2) {
2493 expression_error(expr, "cast from unknown type");
2494 goto out;
2495 }
2496 class2 = classify_type(t2, &t2);
2497
2498 if (class2 & TYPE_COMPOUND)
2499 warning(expr->pos, "cast from non-scalar");
2500
2501 /* allowed cast unfouls */
2502 if (class2 & TYPE_FOULED)
2503 t2 = t2->ctype.base_type;
2504
2505 if (!(ctype->ctype.modifiers & MOD_FORCE) && t1 != t2) {
2506 if (class1 & TYPE_RESTRICT)
2507 warning(expr->pos, "cast to restricted type");
2508 if (class2 & TYPE_RESTRICT)
2509 warning(expr->pos, "cast from restricted type");
2510 }
2511
2512 as1 = get_as(ctype);
2513 as2 = get_as(target->ctype);
2514 if (!as1 && as2 > 0)
2515 warning(expr->pos, "cast removes address space of expression");
2516 if (as1 > 0 && as2 > 0 && as1 != as2)
2517 warning(expr->pos, "cast between address spaces (<asn:%d>-><asn:%d>)", as2, as1);
2518 if (as1 > 0 && !as2)
2519 cast_to_as(expr, as1);
2520
2521 /*
2522 * Casts of constant values are special: they
2523 * can be NULL, and thus need to be simplified
2524 * early.
2525 */
2526 if (target->type == EXPR_VALUE)
2527 cast_value(expr, ctype, target, target->ctype);
2528
2529 out:
2530 return ctype;
2531 }
2532
2533 /*
2534 * Evaluate a call expression with a symbol. This
2535 * should expand inline functions, and evaluate
2536 * builtins.
2537 */
2538 static int evaluate_symbol_call(struct expression *expr)
2539 {
2540 struct expression *fn = expr->fn;
2541 struct symbol *ctype = fn->ctype;
2542
2543 if (fn->type != EXPR_PREOP)
2544 return 0;
2545
2546 if (ctype->op && ctype->op->evaluate)
2547 return ctype->op->evaluate(expr);
2548
2549 if (ctype->ctype.modifiers & MOD_INLINE) {
2550 int ret;
2551 struct symbol *curr = current_fn;
2552 current_fn = ctype->ctype.base_type;
2553
2554 ret = inline_function(expr, ctype);
2555
2556 /* restore the old function */
2557 current_fn = curr;
2558 return ret;
2559 }
2560
2561 return 0;
2562 }
2563
2564 static struct symbol *evaluate_call(struct expression *expr)
2565 {
2566 int args, fnargs;
2567 struct symbol *ctype, *sym;
2568 struct expression *fn = expr->fn;
2569 struct expression_list *arglist = expr->args;
2570
2571 if (!evaluate_expression(fn))
2572 return NULL;
2573 sym = ctype = fn->ctype;
2574 if (ctype->type == SYM_NODE)
2575 ctype = ctype->ctype.base_type;
2576 if (ctype->type == SYM_PTR || ctype->type == SYM_ARRAY)
2577 ctype = get_base_type(ctype);
2578
2579 examine_fn_arguments(ctype);
2580 if (sym->type == SYM_NODE && fn->type == EXPR_PREOP &&
2581 sym->op && sym->op->args) {
2582 if (!sym->op->args(expr))
2583 return NULL;
2584 } else {
2585 if (!evaluate_arguments(sym, ctype, arglist))
2586 return NULL;
2587 if (ctype->type != SYM_FN) {
2588 expression_error(expr, "not a function %s",
2589 show_ident(sym->ident));
2590 return NULL;
2591 }
2592 args = expression_list_size(expr->args);
2593 fnargs = symbol_list_size(ctype->arguments);
2594 if (args < fnargs)
2595 expression_error(expr,
2596 "not enough arguments for function %s",
2597 show_ident(sym->ident));
2598 if (args > fnargs && !ctype->variadic)
2599 expression_error(expr,
2600 "too many arguments for function %s",
2601 show_ident(sym->ident));
2602 }
2603 if (sym->type == SYM_NODE) {
2604 if (evaluate_symbol_call(expr))
2605 return expr->ctype;
2606 }
2607 expr->ctype = ctype->ctype.base_type;
2608 return expr->ctype;
2609 }
2610
2611 struct symbol *evaluate_expression(struct expression *expr)
2612 {
2613 if (!expr)
2614 return NULL;
2615 if (expr->ctype)
2616 return expr->ctype;
2617
2618 switch (expr->type) {
2619 case EXPR_VALUE:
2620 case EXPR_FVALUE:
2621 expression_error(expr, "value expression without a type");
2622 return NULL;
2623 case EXPR_STRING:
2624 return evaluate_string(expr);
2625 case EXPR_SYMBOL:
2626 return evaluate_symbol_expression(expr);
2627 case EXPR_BINOP:
2628 if (!evaluate_expression(expr->left))
2629 return NULL;
2630 if (!evaluate_expression(expr->right))
2631 return NULL;
2632 return evaluate_binop(expr);
2633 case EXPR_LOGICAL:
2634 return evaluate_logical(expr);
2635 case EXPR_COMMA:
2636 evaluate_expression(expr->left);
2637 if (!evaluate_expression(expr->right))
2638 return NULL;
2639 return evaluate_comma(expr);
2640 case EXPR_COMPARE:
2641 if (!evaluate_expression(expr->left))
2642 return NULL;
2643 if (!evaluate_expression(expr->right))
2644 return NULL;
2645 return evaluate_compare(expr);
2646 case EXPR_ASSIGNMENT:
2647 if (!evaluate_expression(expr->left))
2648 return NULL;
2649 if (!evaluate_expression(expr->right))
2650 return NULL;
2651 return evaluate_assignment(expr);
2652 case EXPR_PREOP:
2653 if (!evaluate_expression(expr->unop))
2654 return NULL;
2655 return evaluate_preop(expr);
2656 case EXPR_POSTOP:
2657 if (!evaluate_expression(expr->unop))
2658 return NULL;
2659 return evaluate_postop(expr);
2660 case EXPR_CAST:
2661 case EXPR_IMPLIED_CAST:
2662 return evaluate_cast(expr);
2663 case EXPR_SIZEOF:
2664 return evaluate_sizeof(expr);
2665 case EXPR_PTRSIZEOF:
2666 return evaluate_ptrsizeof(expr);
2667 case EXPR_ALIGNOF:
2668 return evaluate_alignof(expr);
2669 case EXPR_DEREF:
2670 return evaluate_member_dereference(expr);
2671 case EXPR_CALL:
2672 return evaluate_call(expr);
2673 case EXPR_SELECT:
2674 case EXPR_CONDITIONAL:
2675 return evaluate_conditional_expression(expr);
2676 case EXPR_STATEMENT:
2677 expr->ctype = evaluate_statement(expr->statement);
2678 return expr->ctype;
2679
2680 case EXPR_LABEL:
2681 expr->ctype = &ptr_ctype;
2682 return &ptr_ctype;
2683
2684 case EXPR_TYPE:
2685 /* Evaluate the type of the symbol .. */
2686 evaluate_symbol(expr->symbol);
2687 /* .. but the type of the _expression_ is a "type" */
2688 expr->ctype = &type_ctype;
2689 return &type_ctype;
2690
2691 /* These can not exist as stand-alone expressions */
2692 case EXPR_INITIALIZER:
2693 case EXPR_IDENTIFIER:
2694 case EXPR_INDEX:
2695 case EXPR_POS:
2696 expression_error(expr, "internal front-end error: initializer in expression");
2697 return NULL;
2698 case EXPR_SLICE:
2699 expression_error(expr, "internal front-end error: SLICE re-evaluated");
2700 return NULL;
2701 }
2702 return NULL;
2703 }
2704
2705 static void check_duplicates(struct symbol *sym)
2706 {
2707 int declared = 0;
2708 struct symbol *next = sym;
2709
2710 while ((next = next->same_symbol) != NULL) {
2711 const char *typediff;
2712 evaluate_symbol(next);
2713 declared++;
2714 typediff = type_difference(sym, next, 0, 0);
2715 if (typediff) {
2716 sparse_error(sym->pos, "symbol '%s' redeclared with different type (originally declared at %s:%d) - %s",
2717 show_ident(sym->ident),
2718 stream_name(next->pos.stream), next->pos.line, typediff);
2719 return;
2720 }
2721 }
2722 if (!declared) {
2723 unsigned long mod = sym->ctype.modifiers;
2724 if (mod & (MOD_STATIC | MOD_REGISTER))
2725 return;
2726 if (!(mod & MOD_TOPLEVEL))
2727 return;
2728 if (!Wdecl)
2729 return;
2730 if (sym->ident == &main_ident)
2731 return;
2732 warning(sym->pos, "symbol '%s' was not declared. Should it be static?", show_ident(sym->ident));
2733 }
2734 }
2735
2736 static struct symbol *evaluate_symbol(struct symbol *sym)
2737 {
2738 struct symbol *base_type;
2739
2740 if (!sym)
2741 return sym;
2742 if (sym->evaluated)
2743 return sym;
2744 sym->evaluated = 1;
2745
2746 sym = examine_symbol_type(sym);
2747 base_type = get_base_type(sym);
2748 if (!base_type)
2749 return NULL;
2750
2751 /* Evaluate the initializers */
2752 if (sym->initializer)
2753 evaluate_initializer(sym, &sym->initializer);
2754
2755 /* And finally, evaluate the body of the symbol too */
2756 if (base_type->type == SYM_FN) {
2757 struct symbol *curr = current_fn;
2758
2759 current_fn = base_type;
2760
2761 examine_fn_arguments(base_type);
2762 if (!base_type->stmt && base_type->inline_stmt)
2763 uninline(sym);
2764 if (base_type->stmt)
2765 evaluate_statement(base_type->stmt);
2766
2767 current_fn = curr;
2768 }
2769
2770 return base_type;
2771 }
2772
2773 void evaluate_symbol_list(struct symbol_list *list)
2774 {
2775 struct symbol *sym;
2776
2777 FOR_EACH_PTR(list, sym) {
2778 evaluate_symbol(sym);
2779 check_duplicates(sym);
2780 } END_FOR_EACH_PTR(sym);
2781 }
2782
2783 static struct symbol *evaluate_return_expression(struct statement *stmt)
2784 {
2785 struct expression *expr = stmt->expression;
2786 struct symbol *fntype;
2787
2788 evaluate_expression(expr);
2789 fntype = current_fn->ctype.base_type;
2790 if (!fntype || fntype == &void_ctype) {
2791 if (expr && expr->ctype != &void_ctype)
2792 expression_error(expr, "return expression in %s function", fntype?"void":"typeless");
2793 return NULL;
2794 }
2795
2796 if (!expr) {
2797 sparse_error(stmt->pos, "return with no return value");
2798 return NULL;
2799 }
2800 if (!expr->ctype)
2801 return NULL;
2802 compatible_assignment_types(expr, fntype, &stmt->expression, "return expression");
2803 return NULL;
2804 }
2805
2806 static void evaluate_if_statement(struct statement *stmt)
2807 {
2808 if (!stmt->if_conditional)
2809 return;
2810
2811 evaluate_conditional(stmt->if_conditional, 0);
2812 evaluate_statement(stmt->if_true);
2813 evaluate_statement(stmt->if_false);
2814 }
2815
2816 static void evaluate_iterator(struct statement *stmt)
2817 {
2818 evaluate_conditional(stmt->iterator_pre_condition, 1);
2819 evaluate_conditional(stmt->iterator_post_condition,1);
2820 evaluate_statement(stmt->iterator_pre_statement);
2821 evaluate_statement(stmt->iterator_statement);
2822 evaluate_statement(stmt->iterator_post_statement);
2823 }
2824
2825 static void verify_output_constraint(struct expression *expr, const char *constraint)
2826 {
2827 switch (*constraint) {
2828 case '=': /* Assignment */
2829 case '+': /* Update */
2830 break;
2831 default:
2832 expression_error(expr, "output constraint is not an assignment constraint (\"%s\")", constraint);
2833 }
2834 }
2835
2836 static void verify_input_constraint(struct expression *expr, const char *constraint)
2837 {
2838 switch (*constraint) {
2839 case '=': /* Assignment */
2840 case '+': /* Update */
2841 expression_error(expr, "input constraint with assignment (\"%s\")", constraint);
2842 }
2843 }
2844
2845 static void evaluate_asm_statement(struct statement *stmt)
2846 {
2847 struct expression *expr;
2848 int state;
2849
2850 expr = stmt->asm_string;
2851 if (!expr || expr->type != EXPR_STRING) {
2852 sparse_error(stmt->pos, "need constant string for inline asm");
2853 return;
2854 }
2855
2856 state = 0;
2857 FOR_EACH_PTR(stmt->asm_outputs, expr) {
2858 struct ident *ident;
2859
2860 switch (state) {
2861 case 0: /* Identifier */
2862 state = 1;
2863 ident = (struct ident *)expr;
2864 continue;
2865
2866 case 1: /* Constraint */
2867 state = 2;
2868 if (!expr || expr->type != EXPR_STRING) {
2869 sparse_error(expr ? expr->pos : stmt->pos, "asm output constraint is not a string");
2870 *THIS_ADDRESS(expr) = NULL;
2871 continue;
2872 }
2873 verify_output_constraint(expr, expr->string->data);
2874 continue;
2875
2876 case 2: /* Expression */
2877 state = 0;
2878 if (!evaluate_expression(expr))
2879 return;
2880 if (!lvalue_expression(expr))
2881 warning(expr->pos, "asm output is not an lvalue");
2882 evaluate_assign_to(expr, expr->ctype);
2883 continue;
2884 }
2885 } END_FOR_EACH_PTR(expr);
2886
2887 state = 0;
2888 FOR_EACH_PTR(stmt->asm_inputs, expr) {
2889 struct ident *ident;
2890
2891 switch (state) {
2892 case 0: /* Identifier */
2893 state = 1;
2894 ident = (struct ident *)expr;
2895 continue;
2896
2897 case 1: /* Constraint */
2898 state = 2;
2899 if (!expr || expr->type != EXPR_STRING) {
2900 sparse_error(expr ? expr->pos : stmt->pos, "asm input constraint is not a string");
2901 *THIS_ADDRESS(expr) = NULL;
2902 continue;
2903 }
2904 verify_input_constraint(expr, expr->string->data);
2905 continue;
2906
2907 case 2: /* Expression */
2908 state = 0;
2909 if (!evaluate_expression(expr))
2910 return;
2911 continue;
2912 }
2913 } END_FOR_EACH_PTR(expr);
2914
2915 FOR_EACH_PTR(stmt->asm_clobbers, expr) {
2916 if (!expr) {
2917 sparse_error(stmt->pos, "bad asm output");
2918 return;
2919 }
2920 if (expr->type == EXPR_STRING)
2921 continue;
2922 expression_error(expr, "asm clobber is not a string");
2923 } END_FOR_EACH_PTR(expr);
2924 }
2925
2926 static void evaluate_case_statement(struct statement *stmt)
2927 {
2928 evaluate_expression(stmt->case_expression);
2929 evaluate_expression(stmt->case_to);
2930 evaluate_statement(stmt->case_statement);
2931 }
2932
2933 static void check_case_type(struct expression *switch_expr,
2934 struct expression *case_expr,
2935 struct expression **enumcase)
2936 {
2937 struct symbol *switch_type, *case_type;
2938 int sclass, cclass;
2939
2940 if (!case_expr)
2941 return;
2942
2943 switch_type = switch_expr->ctype;
2944 case_type = evaluate_expression(case_expr);
2945
2946 if (!switch_type || !case_type)
2947 goto Bad;
2948 if (enumcase) {
2949 if (*enumcase)
2950 warn_for_different_enum_types(case_expr->pos, case_type, (*enumcase)->ctype);
2951 else if (is_enum_type(case_type))
2952 *enumcase = case_expr;
2953 }
2954
2955 sclass = classify_type(switch_type, &switch_type);
2956 cclass = classify_type(case_type, &case_type);
2957
2958 /* both should be arithmetic */
2959 if (!(sclass & cclass & TYPE_NUM))
2960 goto Bad;
2961
2962 /* neither should be floating */
2963 if ((sclass | cclass) & TYPE_FLOAT)
2964 goto Bad;
2965
2966 /* if neither is restricted, we are OK */
2967 if (!((sclass | cclass) & TYPE_RESTRICT))
2968 return;
2969
2970 if (!restricted_binop_type(SPECIAL_EQUAL, case_expr, switch_expr,
2971 cclass, sclass, case_type, switch_type))
2972 warning(case_expr->pos, "restricted degrades to integer");
2973
2974 return;
2975
2976 Bad:
2977 expression_error(case_expr, "incompatible types for 'case' statement");
2978 }
2979
2980 static void evaluate_switch_statement(struct statement *stmt)
2981 {
2982 struct symbol *sym;
2983 struct expression *enumcase = NULL;
2984 struct expression **enumcase_holder = &enumcase;
2985 struct expression *sel = stmt->switch_expression;
2986
2987 evaluate_expression(sel);
2988 evaluate_statement(stmt->switch_statement);
2989 if (!sel)
2990 return;
2991 if (sel->ctype && is_enum_type(sel->ctype))
2992 enumcase_holder = NULL; /* Only check cases against switch */
2993
2994 FOR_EACH_PTR(stmt->switch_case->symbol_list, sym) {
2995 struct statement *case_stmt = sym->stmt;
2996 check_case_type(sel, case_stmt->case_expression, enumcase_holder);
2997 check_case_type(sel, case_stmt->case_to, enumcase_holder);
2998 } END_FOR_EACH_PTR(sym);
2999 }
3000
3001 struct symbol *evaluate_statement(struct statement *stmt)
3002 {
3003 if (!stmt)
3004 return NULL;
3005
3006 switch (stmt->type) {
3007 case STMT_DECLARATION: {
3008 struct symbol *s;
3009 FOR_EACH_PTR(stmt->declaration, s) {
3010 evaluate_symbol(s);
3011 } END_FOR_EACH_PTR(s);
3012 return NULL;
3013 }
3014
3015 case STMT_RETURN:
3016 return evaluate_return_expression(stmt);
3017
3018 case STMT_EXPRESSION:
3019 if (!evaluate_expression(stmt->expression))
3020 return NULL;
3021 return degenerate(stmt->expression);
3022
3023 case STMT_COMPOUND: {
3024 struct statement *s;
3025 struct symbol *type = NULL;
3026
3027 /* Evaluate the return symbol in the compound statement */
3028 evaluate_symbol(stmt->ret);
3029
3030 /*
3031 * Then, evaluate each statement, making the type of the
3032 * compound statement be the type of the last statement
3033 */
3034 type = evaluate_statement(stmt->args);
3035 FOR_EACH_PTR(stmt->stmts, s) {
3036 type = evaluate_statement(s);
3037 } END_FOR_EACH_PTR(s);
3038 if (!type)
3039 type = &void_ctype;
3040 return type;
3041 }
3042 case STMT_IF:
3043 evaluate_if_statement(stmt);
3044 return NULL;
3045 case STMT_ITERATOR:
3046 evaluate_iterator(stmt);
3047 return NULL;
3048 case STMT_SWITCH:
3049 evaluate_switch_statement(stmt);
3050 return NULL;
3051 case STMT_CASE:
3052 evaluate_case_statement(stmt);
3053 return NULL;
3054 case STMT_LABEL:
3055 return evaluate_statement(stmt->label_statement);
3056 case STMT_GOTO:
3057 evaluate_expression(stmt->goto_expression);
3058 return NULL;
3059 case STMT_NONE:
3060 break;
3061 case STMT_ASM:
3062 evaluate_asm_statement(stmt);
3063 return NULL;
3064 case STMT_CONTEXT:
3065 evaluate_expression(stmt->expression);
3066 return NULL;
3067 case STMT_RANGE:
3068 evaluate_expression(stmt->range_expression);
3069 evaluate_expression(stmt->range_low);
3070 evaluate_expression(stmt->range_high);
3071 return NULL;
3072 }
3073 return NULL;
3074 }
Static analysis for C