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Warn about casts that remove address space information.
[smatch.git] / symbol.c
blobc3bca317fdd422cf133c88b570ae355a4d7b030d
1 /*
2 * Symbol lookup and handling.
3 *
4 * Copyright (C) 2003 Transmeta Corp.
5 * 2003 Linus Torvalds
6 *
7 * Licensed under the Open Software License version 1.1
8 */
9 #include <stdlib.h>
10 #include <stdio.h>
11 #include <stdlib.h>
12 #include <string.h>
13
14 #include "lib.h"
15 #include "token.h"
16 #include "parse.h"
17 #include "symbol.h"
18 #include "scope.h"
19 #include "expression.h"
20
21 #include "target.h"
22
23 /*
24 * Secondary symbol list for stuff that needs to be output because it
25 * was used.
26 */
27 struct symbol_list *used_list = NULL;
28
29 /*
30 * If the symbol is an inline symbol, add it to the list of symbols to parse
31 */
32 void access_symbol(struct symbol *sym)
33 {
34 if (sym->ctype.modifiers & MOD_INLINE) {
35 if (!(sym->ctype.modifiers & MOD_ACCESSED)) {
36 add_symbol(&used_list, sym);
37 sym->ctype.modifiers |= MOD_ACCESSED;
38 }
39 }
40 }
41
42 struct symbol *lookup_symbol(struct ident *ident, enum namespace ns)
43 {
44 struct symbol *sym;
45
46 for (sym = ident->symbols; sym; sym = sym->next_id) {
47 if (sym->namespace & ns) {
48 sym->used = 1;
49 return sym;
50 }
51 }
52 return sym;
53 }
54
55 struct symbol *alloc_symbol(struct position pos, int type)
56 {
57 struct symbol *sym = __alloc_symbol(0);
58 sym->type = type;
59 sym->pos = pos;
60 return sym;
61 }
62
63 struct struct_union_info {
64 unsigned long max_align;
65 unsigned long bit_size;
66 };
67
68 /*
69 * Unions are easy to lay out ;)
70 */
71 static void lay_out_union(struct symbol *sym, void *_info, int flags)
72 {
73 struct struct_union_info *info = _info;
74
75 examine_symbol_type(sym);
76 if (sym->ctype.alignment > info->max_align)
77 info->max_align = sym->ctype.alignment;
78 if (sym->bit_size > info->bit_size)
79 info->bit_size = sym->bit_size;
80
81 sym->offset = 0;
82 }
83
84 /*
85 * Structures are a bit more interesting to lay out
86 */
87 static void lay_out_struct(struct symbol *sym, void *_info, int flags)
88 {
89 struct struct_union_info *info = _info;
90 unsigned long bit_size, base_size;
91 unsigned long align_bit_mask;
92
93 examine_symbol_type(sym);
94 if (sym->ctype.alignment > info->max_align)
95 info->max_align = sym->ctype.alignment;
96
97 bit_size = info->bit_size;
98 base_size = sym->bit_size;
99 align_bit_mask = (sym->ctype.alignment << 3) - 1;
100
101 /*
102 * Bitfields have some very special rules..
103 */
104 if (sym->fieldwidth) {
105 unsigned long bit_offset = bit_size & align_bit_mask;
106
107 if (bit_offset + sym->fieldwidth > base_size) {
108 bit_size = (bit_size + align_bit_mask) & ~align_bit_mask;
109 bit_offset = 0;
110 }
111 sym->offset = (bit_size - bit_offset) >> 3;
112 sym->bit_offset = bit_offset;
113 info->bit_size = bit_size + sym->fieldwidth;
114 return;
115 }
116
117 /*
118 * Otherwise, just align it right and add it up..
119 */
120 bit_size = (bit_size + align_bit_mask) & ~align_bit_mask;
121 sym->offset = bit_size >> 3;
122
123 info->bit_size = bit_size + sym->bit_size;
124 }
125
126 static void examine_struct_union_type(struct symbol *sym, int advance)
127 {
128 struct struct_union_info info = { 1, 0 };
129 unsigned long bit_size, bit_align;
130 void (*fn)(struct symbol *, void *, int);
131
132 fn = advance ? lay_out_struct : lay_out_union;
133 symbol_iterate(sym->symbol_list, fn, &info);
134
135 if (!sym->ctype.alignment)
136 sym->ctype.alignment = info.max_align;
137 bit_size = info.bit_size;
138 bit_align = (sym->ctype.alignment << 3)-1;
139 bit_size = (bit_size + bit_align) & ~bit_align;
140 sym->bit_size = bit_size;
141 }
142
143 static void examine_array_type(struct symbol *sym)
144 {
145 struct symbol *base_type = sym->ctype.base_type;
146 unsigned long bit_size, alignment;
147
148 if (!base_type)
149 return;
150 examine_symbol_type(base_type);
151 bit_size = base_type->bit_size * get_expression_value(sym->array_size);
152 if (!sym->array_size)
153 bit_size = -1;
154 alignment = base_type->ctype.alignment;
155 if (!sym->ctype.alignment)
156 sym->ctype.alignment = alignment;
157 sym->bit_size = bit_size;
158 }
159
160 static void examine_bitfield_type(struct symbol *sym)
161 {
162 struct symbol *base_type = sym->ctype.base_type;
163 unsigned long bit_size, alignment;
164
165 if (!base_type)
166 return;
167 examine_symbol_type(base_type);
168 bit_size = base_type->bit_size;
169 if (sym->fieldwidth > bit_size) {
170 warn(sym->pos, "impossible field-width for this type");
171 sym->fieldwidth = bit_size;
172 }
173 alignment = base_type->ctype.alignment;
174 if (!sym->ctype.alignment)
175 sym->ctype.alignment = alignment;
176 sym->bit_size = bit_size;
177 }
178
179 /*
180 * "typeof" will have to merge the types together
181 */
182 void merge_type(struct symbol *sym, struct symbol *base_type)
183 {
184 sym->ctype.as |= base_type->ctype.as;
185 sym->ctype.modifiers |= (base_type->ctype.modifiers & ~MOD_STORAGE);
186 sym->ctype.context |= base_type->ctype.context;
187 sym->ctype.contextmask |= base_type->ctype.contextmask;
188 sym->ctype.base_type = base_type->ctype.base_type;
189 }
190
191 /*
192 * Fill in type size and alignment information for
193 * regular SYM_TYPE things.
194 */
195 struct symbol *examine_symbol_type(struct symbol * sym)
196 {
197 unsigned int bit_size, alignment;
198 struct symbol *base_type;
199 unsigned long modifiers;
200
201 if (!sym)
202 return sym;
203
204 /* Already done? */
205 if (sym->bit_size)
206 return sym;
207
208 switch (sym->type) {
209 case SYM_ARRAY:
210 examine_array_type(sym);
211 return sym;
212 case SYM_STRUCT:
213 examine_struct_union_type(sym, 1);
214 return sym;
215 case SYM_UNION:
216 examine_struct_union_type(sym, 0);
217 return sym;
218 case SYM_PTR:
219 if (!sym->bit_size)
220 sym->bit_size = bits_in_pointer;
221 if (!sym->ctype.alignment)
222 sym->ctype.alignment = pointer_alignment;
223 base_type = sym->ctype.base_type;
224 base_type = examine_symbol_type(base_type);
225 if (base_type && base_type->type == SYM_NODE)
226 merge_type(sym, base_type);
227 return sym;
228 case SYM_ENUM:
229 if (!sym->bit_size)
230 sym->bit_size = bits_in_enum;
231 if (!sym->ctype.alignment)
232 sym->ctype.alignment = enum_alignment;
233 return sym;
234 case SYM_BITFIELD:
235 examine_bitfield_type(sym);
236 return sym;
237 case SYM_BASETYPE:
238 /* Size and alignment had better already be set up */
239 return sym;
240 case SYM_TYPEOF: {
241 struct symbol *base = evaluate_expression(sym->initializer);
242 if (base)
243 return base;
244 break;
245 }
246 default:
247 break;
248 }
249
250 /* SYM_NODE - figure out what the type of the node was.. */
251 base_type = sym->ctype.base_type;
252 modifiers = sym->ctype.modifiers;
253
254 if (base_type) {
255 base_type = examine_symbol_type(base_type);
256 sym->ctype.base_type = base_type;
257 if (base_type && base_type->type == SYM_NODE)
258 merge_type(sym, base_type);
259
260 bit_size = base_type->bit_size;
261 alignment = base_type->ctype.alignment;
262 if (base_type->fieldwidth)
263 sym->fieldwidth = base_type->fieldwidth;
264 } else
265 bit_size = 0;
266
267 if (!sym->ctype.alignment)
268 sym->ctype.alignment = alignment;
269 sym->bit_size = bit_size;
270 return sym;
271 }
272
273 void check_declaration(struct symbol *sym)
274 {
275 struct symbol *next = sym;
276
277 while ((next = next->next_id) != NULL) {
278 if (next->namespace != sym->namespace)
279 continue;
280 if (sym->scope == next->scope) {
281 sym->same_symbol = next;
282 return;
283 }
284 if (sym->ctype.modifiers & next->ctype.modifiers & MOD_EXTERN) {
285 sym->same_symbol = next;
286 return;
287 }
288 #if 0
289 // This may make sense from a warning standpoint:
290 // consider top-level symbols to clash with everything
291 // (but the scoping rules will mean that we actually
292 // _use_ the innermost version)
293 if (toplevel(next->scope)) {
294 sym->same_symbol = next;
295 return;
296 }
297 #endif
298 }
299 }
300
301 void bind_symbol(struct symbol *sym, struct ident *ident, enum namespace ns)
302 {
303 struct scope *scope;
304 if (sym->id_list) {
305 warn(sym->pos, "internal error: symbol type already bound");
306 return;
307 }
308 sym->namespace = ns;
309 sym->next_id = ident->symbols;
310 ident->symbols = sym;
311 sym->id_list = &ident->symbols;
312
313 scope = block_scope;
314 if (ns != NS_TYPEDEF && toplevel(scope)) {
315 sym->ctype.modifiers |= MOD_TOPLEVEL | MOD_ADDRESSABLE;
316 if (sym->ctype.modifiers & MOD_STATIC)
317 scope = file_scope;
318 }
319 if (ns == NS_LABEL)
320 scope = function_scope;
321 bind_scope(sym, scope);
322 }
323
324 static struct symbol *create_symbol(int stream, const char *name, int type, int namespace)
325 {
326 struct token *token = built_in_token(stream, name);
327 struct symbol *sym = alloc_symbol(token->pos, type);
328
329 sym->ident = token->ident;
330 bind_symbol(sym, token->ident, namespace);
331 return sym;
332 }
333
334 static int evaluate_constant_p(struct expression *expr)
335 {
336 expr->ctype = &int_ctype;
337 return 1;
338 }
339
340 static void expand_constant_p(struct expression *expr)
341 {
342 struct expression *arg;
343 struct expression_list *arglist = expr->args;
344 int value = 1;
345
346 FOR_EACH_PTR (arglist, arg) {
347 if (arg->type != EXPR_VALUE)
348 value = 0;
349 } END_FOR_EACH_PTR;
350
351 expr->type = EXPR_VALUE;
352 expr->value = value;
353 }
354
355 /*
356 * Type and storage class keywords need to have the symbols
357 * created for them, so that the parser can have enough semantic
358 * information to do parsing.
359 *
360 * "double" == "long float", "long double" == "long long float"
361 */
362 struct sym_init {
363 const char *name;
364 struct symbol *base_type;
365 unsigned int modifiers;
366 struct symbol_op *op;
367 } symbol_init_table[] = {
368 /* Storage class */
369 { "auto", NULL, MOD_AUTO },
370 { "register", NULL, MOD_REGISTER },
371 { "static", NULL, MOD_STATIC },
372 { "extern", NULL, MOD_EXTERN },
373
374 /* Type specifiers */
375 { "void", &void_ctype, 0 },
376 { "char", NULL, MOD_CHAR },
377 { "short", NULL, MOD_SHORT },
378 { "int", &int_type, 0 },
379 { "long", NULL, MOD_LONG },
380 { "float", &fp_type, 0 },
381 { "double", &fp_type, MOD_LONG },
382 { "signed", NULL, MOD_SIGNED },
383 { "__signed", NULL, MOD_SIGNED },
384 { "__signed__", NULL, MOD_SIGNED },
385 { "unsigned", NULL, MOD_UNSIGNED },
386 { "__label__", &label_type, MOD_LABEL | MOD_UNSIGNED },
387
388 /* Type qualifiers */
389 { "const", NULL, MOD_CONST },
390 { "__const", NULL, MOD_CONST },
391 { "__const__", NULL, MOD_CONST },
392 { "volatile", NULL, MOD_VOLATILE },
393 { "__volatile", NULL, MOD_VOLATILE },
394 { "__volatile__", NULL, MOD_VOLATILE },
395
396 /* Predeclared types */
397 { "__builtin_va_list", &int_type, 0 },
398
399 /* Typedef.. */
400 { "typedef", NULL, MOD_TYPEDEF },
401
402 /* Extended types */
403 { "typeof", NULL, MOD_TYPEOF },
404 { "__typeof", NULL, MOD_TYPEOF },
405 { "__typeof__", NULL, MOD_TYPEOF },
406
407 #if 0
408 { "attribute", NULL, MOD_ATTRIBUTE },
409 #endif
410 { "__attribute", NULL, MOD_ATTRIBUTE },
411 { "__attribute__", NULL, MOD_ATTRIBUTE },
412
413 { "struct", NULL, MOD_STRUCTOF },
414 { "union", NULL, MOD_UNIONOF },
415 { "enum", NULL, MOD_ENUMOF },
416
417 { "inline", NULL, MOD_INLINE },
418 { "__inline", NULL, MOD_INLINE },
419 { "__inline__", NULL, MOD_INLINE },
420
421 /* Ignored for now.. */
422 { "restrict", NULL, 0 },
423 { "__restrict", NULL, 0 },
424
425 { NULL, NULL, 0 }
426 };
427
428 struct symbol_op constant_p_op = {
429 .evaluate = evaluate_constant_p,
430 .expand = expand_constant_p
431 };
432
433 /*
434 * Builtin functions
435 */
436 static struct symbol builtin_fn_type = { .type = SYM_FN };
437 struct sym_init eval_init_table[] = {
438 { "__builtin_constant_p", &builtin_fn_type, MOD_TOPLEVEL, &constant_p_op },
439
440 { NULL, NULL, 0 }
441 };
442
443
444 /*
445 * Abstract types
446 */
447 struct symbol int_type,
448 fp_type,
449 label_type,
450 vector_type,
451 bad_type;
452
453 /*
454 * C types (ie actual instances that the abstract types
455 * can map onto)
456 */
457 struct symbol bool_ctype, void_ctype, type_ctype,
458 char_ctype, uchar_ctype,
459 short_ctype, ushort_ctype,
460 int_ctype, uint_ctype,
461 long_ctype, ulong_ctype,
462 llong_ctype, ullong_ctype,
463 float_ctype, double_ctype, ldouble_ctype,
464 string_ctype, ptr_ctype, label_ctype;
465
466 struct ctype_declare {
467 struct symbol *ptr;
468 unsigned long modifiers;
469 int *bit_size;
470 int *maxalign;
471 struct symbol *base_type;
472 } ctype_declaration[] = {
473 { &bool_ctype, 0, &bits_in_int, &max_int_alignment, &int_type },
474 { &void_ctype, 0, NULL, NULL, NULL },
475 { &type_ctype, MOD_TYPE, NULL, NULL, NULL },
476 { &label_ctype, MOD_LABEL | MOD_UNSIGNED, &bits_in_pointer, &max_int_alignment, &label_type },
477
478 { &char_ctype, MOD_SIGNED | MOD_CHAR, &bits_in_char, &max_int_alignment, &int_type },
479 { &uchar_ctype, MOD_UNSIGNED | MOD_CHAR, &bits_in_char, &max_int_alignment, &int_type },
480 { &short_ctype, MOD_SIGNED | MOD_SHORT, &bits_in_short, &max_int_alignment, &int_type },
481 { &ushort_ctype, MOD_UNSIGNED | MOD_SHORT, &bits_in_short, &max_int_alignment, &int_type },
482 { &int_ctype, MOD_SIGNED, &bits_in_int, &max_int_alignment, &int_type },
483 { &uint_ctype, MOD_UNSIGNED, &bits_in_int, &max_int_alignment, &int_type },
484 { &long_ctype, MOD_SIGNED | MOD_LONG, &bits_in_long, &max_int_alignment, &int_type },
485 { &ulong_ctype, MOD_UNSIGNED | MOD_LONG, &bits_in_long, &max_int_alignment, &int_type },
486 { &llong_ctype, MOD_SIGNED | MOD_LONG | MOD_LONGLONG, &bits_in_longlong, &max_int_alignment, &int_type },
487 { &ullong_ctype, MOD_UNSIGNED | MOD_LONG | MOD_LONGLONG, &bits_in_longlong, &max_int_alignment, &int_type },
488
489 { &float_ctype, 0, &bits_in_float, &max_fp_alignment, &fp_type },
490 { &double_ctype, MOD_LONG, &bits_in_double, &max_fp_alignment, &fp_type },
491 { &ldouble_ctype,MOD_LONG | MOD_LONGLONG, &bits_in_longdouble, &max_fp_alignment, &fp_type },
492
493 { &string_ctype, 0, &bits_in_pointer, &pointer_alignment, &char_ctype },
494 { &ptr_ctype, 0, &bits_in_pointer, &pointer_alignment, &void_ctype },
495 { NULL, }
496 };
497
498
499 #define __INIT_IDENT(str) { .len = sizeof(str)-1, .name = str }
500 #define __IDENT(n,str) \
501 struct ident n ## _ident = __INIT_IDENT(str)
502 #define IDENT(n) __IDENT(n, #n)
503
504 IDENT(struct); IDENT(union); IDENT(enum);
505 IDENT(sizeof);
506 IDENT(alignof); IDENT(__alignof); IDENT(__alignof__);
507 IDENT(if); IDENT(else); IDENT(return);
508 IDENT(switch); IDENT(case); IDENT(default);
509 IDENT(break); IDENT(continue);
510 IDENT(for); IDENT(while); IDENT(do); IDENT(goto);
511
512 IDENT(__asm__); IDENT(__asm); IDENT(asm);
513 IDENT(__volatile__); IDENT(__volatile); IDENT(volatile);
514 IDENT(__attribute__); IDENT(__attribute);
515 IDENT(defined);
516
517 __IDENT(pragma, "__pragma__");
518
519 struct ident __VA_ARGS___ident = __INIT_IDENT("__VA_ARGS__");
520 struct ident __LINE___ident = __INIT_IDENT("__LINE__");
521 struct ident __FILE___ident = __INIT_IDENT("__FILE__");
522
523 void init_symbols(void)
524 {
525 int stream = init_stream("builtin", -1);
526 struct sym_init *ptr;
527
528 hash_ident(&sizeof_ident);
529 hash_ident(&alignof_ident);
530 hash_ident(&__alignof_ident);
531 hash_ident(&__alignof___ident);
532 hash_ident(&if_ident);
533 hash_ident(&else_ident);
534 hash_ident(&return_ident);
535 hash_ident(&switch_ident);
536 hash_ident(&case_ident);
537 hash_ident(&default_ident);
538 hash_ident(&break_ident);
539 hash_ident(&continue_ident);
540 hash_ident(&for_ident);
541 hash_ident(&while_ident);
542 hash_ident(&do_ident);
543 hash_ident(&goto_ident);
544 hash_ident(&__attribute___ident);
545 hash_ident(&__attribute_ident);
546 hash_ident(&__asm___ident);
547 hash_ident(&__asm_ident);
548 hash_ident(&asm_ident);
549 hash_ident(&__volatile___ident);
550 hash_ident(&__volatile_ident);
551 hash_ident(&volatile_ident);
552 hash_ident(&defined_ident);
553 hash_ident(&__LINE___ident);
554 hash_ident(&__FILE___ident);
555 hash_ident(&__VA_ARGS___ident);
556 hash_ident(&pragma_ident);
557 for (ptr = symbol_init_table; ptr->name; ptr++) {
558 struct symbol *sym;
559 sym = create_symbol(stream, ptr->name, SYM_NODE, NS_TYPEDEF);
560 sym->ctype.base_type = ptr->base_type;
561 sym->ctype.modifiers = ptr->modifiers;
562 }
563
564 builtin_fn_type.variadic = 1;
565 for (ptr = eval_init_table; ptr->name; ptr++) {
566 struct symbol *sym;
567 sym = create_symbol(stream, ptr->name, SYM_NODE, NS_SYMBOL);
568 sym->ctype.base_type = ptr->base_type;
569 sym->ctype.modifiers = ptr->modifiers;
570 sym->op = ptr->op;
571 }
572 }
573
574 void init_ctype(void)
575 {
576 struct ctype_declare *ctype;
577
578 ptr_ctype.type = SYM_PTR;
579 string_ctype.type = SYM_PTR;
580 for (ctype = ctype_declaration ; ctype->ptr; ctype++) {
581 struct symbol *sym = ctype->ptr;
582 unsigned long bit_size = ctype->bit_size ? *ctype->bit_size : -1;
583 unsigned long maxalign = ctype->maxalign ? *ctype->maxalign : 0;
584 unsigned long alignment = bit_size >> 3;
585
586 if (alignment > maxalign)
587 alignment = maxalign;
588 sym->bit_size = bit_size;
589 sym->ctype.alignment = alignment;
590 sym->ctype.base_type = ctype->base_type;
591 sym->ctype.modifiers = ctype->modifiers;
592 }
593 }
Static analysis for C