1 /* 2 * Copyright (C) 2009 Dan Carpenter. 3 * 4 * This program is free software; you can redistribute it and/or 5 * modify it under the terms of the GNU General Public License 6 * as published by the Free Software Foundation; either version 2 7 * of the License, or (at your option) any later version. 8 * 9 * This program is distributed in the hope that it will be useful, 10 * but WITHOUT ANY WARRANTY; without even the implied warranty of 11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 12 * GNU General Public License for more details. 13 * 14 * You should have received a copy of the GNU General Public License 15 * along with this program; if not, see http://www.gnu.org/copyleft/gpl.txt 16 */ 17 18 /* 19 * The idea here is that you have an expression and you 20 * want to know what the type is for that. 21 */ 22 23 #include "smatch.h" 24 #include "smatch_slist.h" 25 26 struct symbol *get_real_base_type(struct symbol *sym) 27 { 28 struct symbol *ret; 29 30 if (!sym) 31 return NULL; 32 if (sym->type == SYM_BASETYPE) 33 return sym; 34 ret = get_base_type(sym); 35 if (!ret) 36 return NULL; 37 if (ret->type == SYM_RESTRICT || ret->type == SYM_NODE) 38 return get_real_base_type(ret); 39 return ret; 40 } 41 42 int type_bytes(struct symbol *type) 43 { 44 int bits; 45 46 if (type && type->type == SYM_ARRAY) 47 return array_bytes(type); 48 49 bits = type_bits(type); 50 if (bits < 0) 51 return 0; 52 return bits_to_bytes(bits); 53 } 54 55 int array_bytes(struct symbol *type) 56 { 57 if (!type || type->type != SYM_ARRAY) 58 return 0; 59 return bits_to_bytes(type->bit_size); 60 } 61 62 static struct symbol *get_binop_type(struct expression *expr) 63 { 64 struct symbol *left, *right; 65 66 left = get_type(expr->left); 67 if (!left) 68 return NULL; 69 70 if (expr->op == SPECIAL_LEFTSHIFT || 71 expr->op == SPECIAL_RIGHTSHIFT) { 72 if (type_positive_bits(left) < 31) 73 return &int_ctype; 74 return left; 75 } 76 right = get_type(expr->right); 77 if (!right) 78 return NULL; 79 80 if (type_is_fp(left)) { 81 if (type_is_fp(right)) { 82 if (type_bits(left) > type_bits(right)) 83 return left; 84 return right; 85 } 86 return left; 87 } 88 89 if (type_is_fp(right)) { 90 if (type_is_fp(left)) { 91 if (type_bits(right) > type_bits(left)) 92 return right; 93 return left; 94 } 95 return right; 96 } 97 98 if (expr->op == '-' && 99 (is_ptr_type(left) && is_ptr_type(right))) 100 return ssize_t_ctype; 101 102 if (left->type == SYM_PTR || left->type == SYM_ARRAY) 103 return left; 104 if (right->type == SYM_PTR || right->type == SYM_ARRAY) 105 return right; 106 107 if (type_positive_bits(left) < 31 && type_positive_bits(right) < 31) 108 return &int_ctype; 109 110 if (type_positive_bits(left) > type_positive_bits(right)) 111 return left; 112 return right; 113 } 114 115 static struct symbol *get_type_symbol(struct expression *expr) 116 { 117 if (!expr || expr->type != EXPR_SYMBOL || !expr->symbol) 118 return NULL; 119 120 return get_real_base_type(expr->symbol); 121 } 122 123 static struct symbol *get_member_symbol(struct symbol_list *symbol_list, struct ident *member) 124 { 125 struct symbol *tmp, *sub; 126 127 FOR_EACH_PTR(symbol_list, tmp) { 128 if (!tmp->ident) { 129 sub = get_real_base_type(tmp); 130 sub = get_member_symbol(sub->symbol_list, member); 131 if (sub) 132 return sub; 133 continue; 134 } 135 if (tmp->ident == member) 136 return tmp; 137 } END_FOR_EACH_PTR(tmp); 138 139 return NULL; 140 } 141 142 static struct symbol *get_symbol_from_deref(struct expression *expr) 143 { 144 struct ident *member; 145 struct symbol *sym; 146 147 if (!expr || expr->type != EXPR_DEREF) 148 return NULL; 149 150 member = expr->member; 151 sym = get_type(expr->deref); 152 if (!sym) { 153 // sm_msg("could not find struct type"); 154 return NULL; 155 } 156 if (sym->type == SYM_PTR) 157 sym = get_real_base_type(sym); 158 sym = get_member_symbol(sym->symbol_list, member); 159 if (!sym) 160 return NULL; 161 return get_real_base_type(sym); 162 } 163 164 static struct symbol *handle__builtin_choose_expr(struct expression *expr) 165 { 166 struct expression *const_expr, *expr1, *expr2; 167 sval_t sval; 168 169 const_expr = get_argument_from_call_expr(expr->args, 0); 170 expr1 = get_argument_from_call_expr(expr->args, 1); 171 expr2 = get_argument_from_call_expr(expr->args, 2); 172 173 if (!get_value(const_expr, &sval) || !expr1 || !expr2) 174 return NULL; 175 if (sval.value) 176 return get_type(expr1); 177 else 178 return get_type(expr2); 179 } 180 181 static struct symbol *get_return_type(struct expression *expr) 182 { 183 struct symbol *tmp; 184 185 if (sym_name_is("__builtin_choose_expr", expr->fn)) 186 return handle__builtin_choose_expr(expr); 187 188 tmp = get_type(expr->fn); 189 if (!tmp) 190 return NULL; 191 /* this is to handle __builtin_constant_p() */ 192 if (tmp->type != SYM_FN) 193 tmp = get_base_type(tmp); 194 return get_real_base_type(tmp); 195 } 196 197 static struct symbol *get_expr_stmt_type(struct statement *stmt) 198 { 199 if (stmt->type != STMT_COMPOUND) 200 return NULL; 201 stmt = last_ptr_list((struct ptr_list *)stmt->stmts); 202 if (stmt->type == STMT_LABEL) 203 stmt = stmt->label_statement; 204 if (stmt->type != STMT_EXPRESSION) 205 return NULL; 206 return get_type(stmt->expression); 207 } 208 209 static struct symbol *get_select_type(struct expression *expr) 210 { 211 struct symbol *one, *two; 212 213 one = get_type(expr->cond_true); 214 two = get_type(expr->cond_false); 215 if (!one || !two) 216 return NULL; 217 /* 218 * This is a hack. If the types are not equiv then we 219 * really don't know the type. But I think guessing is 220 * probably Ok here. 221 */ 222 if (type_positive_bits(one) > type_positive_bits(two)) 223 return one; 224 return two; 225 } 226 227 struct symbol *get_pointer_type(struct expression *expr) 228 { 229 struct symbol *sym; 230 231 sym = get_type(expr); 232 if (!sym) 233 return NULL; 234 if (sym->type == SYM_NODE) { 235 sym = get_real_base_type(sym); 236 if (!sym) 237 return NULL; 238 } 239 if (sym->type != SYM_PTR && sym->type != SYM_ARRAY) 240 return NULL; 241 return get_real_base_type(sym); 242 } 243 244 static struct symbol *fake_pointer_sym(struct expression *expr) 245 { 246 struct symbol *sym; 247 struct symbol *base; 248 249 sym = alloc_symbol(expr->pos, SYM_PTR); 250 expr = expr->unop; 251 base = get_type(expr); 252 if (!base) 253 return NULL; 254 sym->ctype.base_type = base; 255 return sym; 256 } 257 258 static struct symbol *get_type_helper(struct expression *expr) 259 { 260 struct symbol *ret; 261 262 expr = strip_parens(expr); 263 if (!expr) 264 return NULL; 265 266 if (expr->ctype) 267 return expr->ctype; 268 269 switch (expr->type) { 270 case EXPR_STRING: 271 ret = &string_ctype; 272 break; 273 case EXPR_SYMBOL: 274 ret = get_type_symbol(expr); 275 break; 276 case EXPR_DEREF: 277 ret = get_symbol_from_deref(expr); 278 break; 279 case EXPR_PREOP: 280 case EXPR_POSTOP: 281 if (expr->op == '&') 282 ret = fake_pointer_sym(expr); 283 else if (expr->op == '*') 284 ret = get_pointer_type(expr->unop); 285 else 286 ret = get_type(expr->unop); 287 break; 288 case EXPR_ASSIGNMENT: 289 ret = get_type(expr->left); 290 break; 291 case EXPR_CAST: 292 case EXPR_FORCE_CAST: 293 case EXPR_IMPLIED_CAST: 294 ret = get_real_base_type(expr->cast_type); 295 break; 296 case EXPR_COMPARE: 297 case EXPR_BINOP: 298 ret = get_binop_type(expr); 299 break; 300 case EXPR_CALL: 301 ret = get_return_type(expr); 302 break; 303 case EXPR_STATEMENT: 304 ret = get_expr_stmt_type(expr->statement); 305 break; 306 case EXPR_CONDITIONAL: 307 case EXPR_SELECT: 308 ret = get_select_type(expr); 309 break; 310 case EXPR_SIZEOF: 311 ret = &ulong_ctype; 312 break; 313 case EXPR_LOGICAL: 314 ret = &int_ctype; 315 break; 316 case EXPR_OFFSETOF: 317 ret = &ulong_ctype; 318 break; 319 default: 320 return NULL; 321 } 322 323 if (ret && ret->type == SYM_TYPEOF) 324 ret = get_type(ret->initializer); 325 326 expr->ctype = ret; 327 return ret; 328 } 329 330 static struct symbol *get_final_type_helper(struct expression *expr) 331 { 332 /* 333 * The problem is that I wrote a bunch of Smatch to think that 334 * you could do get_type() on an expression and it would give 335 * you what the comparison was type promoted to. This is wrong 336 * but fixing it is a big of work... Hence this horrible hack. 337 * 338 */ 339 340 expr = strip_parens(expr); 341 if (!expr) 342 return NULL; 343 344 if (expr->type == EXPR_COMPARE) 345 return &int_ctype; 346 347 return NULL; 348 } 349 350 struct symbol *get_type(struct expression *expr) 351 { 352 return get_type_helper(expr); 353 } 354 355 struct symbol *get_final_type(struct expression *expr) 356 { 357 struct symbol *ret; 358 359 ret = get_final_type_helper(expr); 360 if (ret) 361 return ret; 362 return get_type_helper(expr); 363 } 364 365 struct symbol *get_promoted_type(struct symbol *left, struct symbol *right) 366 { 367 struct symbol *ret = &int_ctype; 368 369 if (type_positive_bits(left) > type_positive_bits(ret)) 370 ret = left; 371 if (type_positive_bits(right) > type_positive_bits(ret)) 372 ret = right; 373 374 if (type_is_ptr(left)) 375 ret = left; 376 if (type_is_ptr(right)) 377 ret = right; 378 379 return ret; 380 } 381 382 int type_signed(struct symbol *base_type) 383 { 384 if (!base_type) 385 return 0; 386 if (base_type->ctype.modifiers & MOD_SIGNED) 387 return 1; 388 return 0; 389 } 390 391 int expr_unsigned(struct expression *expr) 392 { 393 struct symbol *sym; 394 395 sym = get_type(expr); 396 if (!sym) 397 return 0; 398 if (type_unsigned(sym)) 399 return 1; 400 return 0; 401 } 402 403 int expr_signed(struct expression *expr) 404 { 405 struct symbol *sym; 406 407 sym = get_type(expr); 408 if (!sym) 409 return 0; 410 if (type_signed(sym)) 411 return 1; 412 return 0; 413 } 414 415 int returns_unsigned(struct symbol *sym) 416 { 417 if (!sym) 418 return 0; 419 sym = get_base_type(sym); 420 if (!sym || sym->type != SYM_FN) 421 return 0; 422 sym = get_base_type(sym); 423 return type_unsigned(sym); 424 } 425 426 int is_pointer(struct expression *expr) 427 { 428 return type_is_ptr(get_type(expr)); 429 } 430 431 int returns_pointer(struct symbol *sym) 432 { 433 if (!sym) 434 return 0; 435 sym = get_base_type(sym); 436 if (!sym || sym->type != SYM_FN) 437 return 0; 438 sym = get_base_type(sym); 439 if (sym && sym->type == SYM_PTR) 440 return 1; 441 return 0; 442 } 443 444 static sval_t fp_max(struct symbol *type) 445 { 446 sval_t ret = { .type = type }; 447 448 if (type == &float_ctype) 449 ret.fvalue = FLT_MAX; 450 else if (type == &double_ctype) 451 ret.dvalue = DBL_MAX; 452 else 453 ret.ldvalue = LDBL_MAX; 454 455 return ret; 456 } 457 458 sval_t sval_type_max(struct symbol *base_type) 459 { 460 sval_t ret; 461 462 if (type_is_fp(base_type)) 463 return fp_max(base_type); 464 465 if (!base_type || !type_bits(base_type)) 466 base_type = &llong_ctype; 467 ret.type = base_type; 468 469 ret.value = (~0ULL) >> (64 - type_positive_bits(base_type)); 470 return ret; 471 } 472 473 static sval_t fp_min(struct symbol *type) 474 { 475 sval_t ret = { .type = type }; 476 477 if (type == &float_ctype) 478 ret.fvalue = -FLT_MAX; 479 else if (type == &double_ctype) 480 ret.dvalue = -DBL_MAX; 481 else 482 ret.ldvalue = -LDBL_MAX; 483 484 return ret; 485 } 486 487 sval_t sval_type_min(struct symbol *base_type) 488 { 489 sval_t ret; 490 491 if (type_is_fp(base_type)) 492 return fp_min(base_type); 493 494 if (!base_type || !type_bits(base_type)) 495 base_type = &llong_ctype; 496 ret.type = base_type; 497 498 if (type_unsigned(base_type) || is_ptr_type(base_type)) { 499 ret.value = 0; 500 return ret; 501 } 502 503 ret.value = (~0ULL) << type_positive_bits(base_type); 504 505 return ret; 506 } 507 508 int nr_bits(struct expression *expr) 509 { 510 struct symbol *type; 511 512 type = get_type(expr); 513 if (!type) 514 return 0; 515 return type_bits(type); 516 } 517 518 int is_void_pointer(struct expression *expr) 519 { 520 struct symbol *type; 521 522 type = get_type(expr); 523 if (!type || type->type != SYM_PTR) 524 return 0; 525 type = get_real_base_type(type); 526 if (type == &void_ctype) 527 return 1; 528 return 0; 529 } 530 531 int is_char_pointer(struct expression *expr) 532 { 533 struct symbol *type; 534 535 type = get_type(expr); 536 if (!type || type->type != SYM_PTR) 537 return 0; 538 type = get_real_base_type(type); 539 if (type == &char_ctype) 540 return 1; 541 return 0; 542 } 543 544 int is_string(struct expression *expr) 545 { 546 expr = strip_expr(expr); 547 if (!expr || expr->type != EXPR_STRING) 548 return 0; 549 if (expr->string) 550 return 1; 551 return 0; 552 } 553 554 int is_static(struct expression *expr) 555 { 556 char *name; 557 struct symbol *sym; 558 int ret = 0; 559 560 name = expr_to_str_sym(expr, &sym); 561 if (!name || !sym) 562 goto free; 563 564 if (sym->ctype.modifiers & MOD_STATIC) 565 ret = 1; 566 free: 567 free_string(name); 568 return ret; 569 } 570 571 bool is_local_variable(struct expression *expr) 572 { 573 struct symbol *sym; 574 575 if (!expr || expr->type != EXPR_SYMBOL || !expr->symbol) 576 return false; 577 sym = expr->symbol; 578 if (!(sym->ctype.modifiers & MOD_TOPLEVEL)) 579 return true; 580 return false; 581 } 582 583 int types_equiv(struct symbol *one, struct symbol *two) 584 { 585 if (!one && !two) 586 return 1; 587 if (!one || !two) 588 return 0; 589 if (one->type != two->type) 590 return 0; 591 if (one->type == SYM_PTR) 592 return types_equiv(get_real_base_type(one), get_real_base_type(two)); 593 if (type_positive_bits(one) != type_positive_bits(two)) 594 return 0; 595 return 1; 596 } 597 598 int fn_static(void) 599 { 600 return !!(cur_func_sym->ctype.modifiers & MOD_STATIC); 601 } 602 603 const char *global_static(void) 604 { 605 if (cur_func_sym->ctype.modifiers & MOD_STATIC) 606 return "static"; 607 else 608 return "global"; 609 } 610 611 struct symbol *cur_func_return_type(void) 612 { 613 struct symbol *sym; 614 615 sym = get_real_base_type(cur_func_sym); 616 if (!sym || sym->type != SYM_FN) 617 return NULL; 618 sym = get_real_base_type(sym); 619 return sym; 620 } 621 622 struct symbol *get_arg_type(struct expression *fn, int arg) 623 { 624 struct symbol *fn_type; 625 struct symbol *tmp; 626 struct symbol *arg_type; 627 int i; 628 629 fn_type = get_type(fn); 630 if (!fn_type) 631 return NULL; 632 if (fn_type->type == SYM_PTR) 633 fn_type = get_real_base_type(fn_type); 634 if (fn_type->type != SYM_FN) 635 return NULL; 636 637 i = 0; 638 FOR_EACH_PTR(fn_type->arguments, tmp) { 639 arg_type = get_real_base_type(tmp); 640 if (i == arg) { 641 return arg_type; 642 } 643 i++; 644 } END_FOR_EACH_PTR(tmp); 645 646 return NULL; 647 } 648 649 static struct symbol *get_member_from_string(struct symbol_list *symbol_list, const char *name) 650 { 651 struct symbol *tmp, *sub; 652 int chunk_len; 653 654 if (strncmp(name, ".", 1) == 0) 655 name += 1; 656 else if (strncmp(name, "->", 2) == 0) 657 name += 2; 658 659 FOR_EACH_PTR(symbol_list, tmp) { 660 if (!tmp->ident) { 661 sub = get_real_base_type(tmp); 662 sub = get_member_from_string(sub->symbol_list, name); 663 if (sub) 664 return sub; 665 continue; 666 } 667 668 if (strcmp(tmp->ident->name, name) == 0) 669 return tmp; 670 671 chunk_len = tmp->ident->len; 672 if (strncmp(tmp->ident->name, name, chunk_len) == 0 && 673 (name[chunk_len] == '.' || name[chunk_len] == '-')) { 674 sub = get_real_base_type(tmp); 675 if (sub->type == SYM_PTR) 676 sub = get_real_base_type(sub); 677 return get_member_from_string(sub->symbol_list, name + chunk_len); 678 } 679 680 } END_FOR_EACH_PTR(tmp); 681 682 return NULL; 683 } 684 685 struct symbol *get_member_type_from_key(struct expression *expr, const char *key) 686 { 687 struct symbol *sym; 688 689 if (strcmp(key, "$") == 0) 690 return get_type(expr); 691 692 if (strcmp(key, "*$") == 0) { 693 sym = get_type(expr); 694 if (!sym || sym->type != SYM_PTR) 695 return NULL; 696 return get_real_base_type(sym); 697 } 698 699 sym = get_type(expr); 700 if (!sym) 701 return NULL; 702 if (sym->type == SYM_PTR) 703 sym = get_real_base_type(sym); 704 705 key = key + 1; 706 sym = get_member_from_string(sym->symbol_list, key); 707 if (!sym) 708 return NULL; 709 return get_real_base_type(sym); 710 } 711 712 struct symbol *get_arg_type_from_key(struct expression *fn, int param, struct expression *arg, const char *key) 713 { 714 struct symbol *type; 715 716 if (!key) 717 return NULL; 718 if (strcmp(key, "$") == 0) 719 return get_arg_type(fn, param); 720 if (strcmp(key, "*$") == 0) { 721 type = get_arg_type(fn, param); 722 if (!type || type->type != SYM_PTR) 723 return NULL; 724 return get_real_base_type(type); 725 } 726 return get_member_type_from_key(arg, key); 727 } 728 729 int is_struct(struct expression *expr) 730 { 731 struct symbol *type; 732 733 type = get_type(expr); 734 if (type && type->type == SYM_STRUCT) 735 return 1; 736 return 0; 737 } 738 739 static struct { 740 struct symbol *sym; 741 const char *name; 742 } base_types[] = { 743 {&bool_ctype, "bool"}, 744 {&void_ctype, "void"}, 745 {&type_ctype, "type"}, 746 {&char_ctype, "char"}, 747 {&schar_ctype, "schar"}, 748 {&uchar_ctype, "uchar"}, 749 {&short_ctype, "short"}, 750 {&sshort_ctype, "sshort"}, 751 {&ushort_ctype, "ushort"}, 752 {&int_ctype, "int"}, 753 {&sint_ctype, "sint"}, 754 {&uint_ctype, "uint"}, 755 {&long_ctype, "long"}, 756 {&slong_ctype, "slong"}, 757 {&ulong_ctype, "ulong"}, 758 {&llong_ctype, "llong"}, 759 {&sllong_ctype, "sllong"}, 760 {&ullong_ctype, "ullong"}, 761 {&lllong_ctype, "lllong"}, 762 {&slllong_ctype, "slllong"}, 763 {&ulllong_ctype, "ulllong"}, 764 {&float_ctype, "float"}, 765 {&double_ctype, "double"}, 766 {&ldouble_ctype, "ldouble"}, 767 {&string_ctype, "string"}, 768 {&ptr_ctype, "ptr"}, 769 {&lazy_ptr_ctype, "lazy_ptr"}, 770 {&incomplete_ctype, "incomplete"}, 771 {&label_ctype, "label"}, 772 {&bad_ctype, "bad"}, 773 {&null_ctype, "null"}, 774 }; 775 776 static const char *base_type_str(struct symbol *sym) 777 { 778 int i; 779 780 for (i = 0; i < ARRAY_SIZE(base_types); i++) { 781 if (sym == base_types[i].sym) 782 return base_types[i].name; 783 } 784 return "<unknown>"; 785 } 786 787 static int type_str_helper(char *buf, int size, struct symbol *type) 788 { 789 int n; 790 791 if (!type) 792 return snprintf(buf, size, "<null type>"); 793 794 if (type->type == SYM_BASETYPE) { 795 return snprintf(buf, size, "%s", base_type_str(type)); 796 } else if (type->type == SYM_PTR) { 797 type = get_real_base_type(type); 798 n = type_str_helper(buf, size, type); 799 if (n > size) 800 return n; 801 return n + snprintf(buf + n, size - n, "*"); 802 } else if (type->type == SYM_ARRAY) { 803 type = get_real_base_type(type); 804 n = type_str_helper(buf, size, type); 805 if (n > size) 806 return n; 807 return n + snprintf(buf + n, size - n, "[]"); 808 } else if (type->type == SYM_STRUCT) { 809 return snprintf(buf, size, "struct %s", type->ident ? type->ident->name : ""); 810 } else if (type->type == SYM_UNION) { 811 if (type->ident) 812 return snprintf(buf, size, "union %s", type->ident->name); 813 else 814 return snprintf(buf, size, "anonymous union"); 815 } else if (type->type == SYM_FN) { 816 struct symbol *arg, *return_type, *arg_type; 817 int i; 818 819 return_type = get_real_base_type(type); 820 n = type_str_helper(buf, size, return_type); 821 if (n > size) 822 return n; 823 n += snprintf(buf + n, size - n, "(*)("); 824 if (n > size) 825 return n; 826 827 i = 0; 828 FOR_EACH_PTR(type->arguments, arg) { 829 if (i++) 830 n += snprintf(buf + n, size - n, ", "); 831 if (n > size) 832 return n; 833 arg_type = get_real_base_type(arg); 834 n += type_str_helper(buf + n, size - n, arg_type); 835 if (n > size) 836 return n; 837 } END_FOR_EACH_PTR(arg); 838 839 return n + snprintf(buf + n, size - n, ")"); 840 } else if (type->type == SYM_NODE) { 841 n = snprintf(buf, size, "node {"); 842 if (n > size) 843 return n; 844 type = get_real_base_type(type); 845 n += type_str_helper(buf + n, size - n, type); 846 if (n > size) 847 return n; 848 return n + snprintf(buf + n, size - n, "}"); 849 } else if (type->type == SYM_ENUM) { 850 return snprintf(buf, size, "enum %s", type->ident ? type->ident->name : "<unknown>"); 851 } else { 852 return snprintf(buf, size, "<type %d>", type->type); 853 } 854 } 855 856 char *type_to_str(struct symbol *type) 857 { 858 static char buf[256]; 859 860 buf[0] = '\0'; 861 type_str_helper(buf, sizeof(buf), type); 862 return buf; 863 } 864