tree.c revision 1.511
1 /* $NetBSD: tree.c,v 1.511 2023/04/11 19:40:04 rillig Exp $ */ 2 3 /* 4 * Copyright (c) 1994, 1995 Jochen Pohl 5 * All Rights Reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. All advertising materials mentioning features or use of this software 16 * must display the following acknowledgement: 17 * This product includes software developed by Jochen Pohl for 18 * The NetBSD Project. 19 * 4. The name of the author may not be used to endorse or promote products 20 * derived from this software without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 23 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 24 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 25 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 26 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 27 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 28 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 29 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 30 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 31 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 32 */ 33 34 #if HAVE_NBTOOL_CONFIG_H 35 #include "nbtool_config.h" 36 #endif 37 38 #include <sys/cdefs.h> 39 #if defined(__RCSID) 40 __RCSID("$NetBSD: tree.c,v 1.511 2023/04/11 19:40:04 rillig Exp $"); 41 #endif 42 43 #include <float.h> 44 #include <limits.h> 45 #include <math.h> 46 #include <signal.h> 47 #include <stdlib.h> 48 #include <string.h> 49 50 #include "lint1.h" 51 52 53 typedef struct integer_constraints { 54 int64_t smin; /* signed minimum */ 55 int64_t smax; /* signed maximum */ 56 uint64_t umin; /* unsigned minimum */ 57 uint64_t umax; /* unsigned maximum */ 58 uint64_t bset; /* bits that are definitely set */ 59 uint64_t bclr; /* bits that are definitely clear */ 60 } integer_constraints; 61 62 63 static uint64_t 64 u64_fill_right(uint64_t x) 65 { 66 x |= x >> 1; 67 x |= x >> 2; 68 x |= x >> 4; 69 x |= x >> 8; 70 x |= x >> 16; 71 x |= x >> 32; 72 return x; 73 } 74 75 static bool 76 str_endswith(const char *haystack, const char *needle) 77 { 78 size_t hlen = strlen(haystack); 79 size_t nlen = strlen(needle); 80 81 return nlen <= hlen && 82 memcmp(haystack + hlen - nlen, needle, nlen) == 0; 83 } 84 static const char * 85 op_name(op_t op) 86 { 87 return modtab[op].m_name; 88 } 89 90 static unsigned 91 width_in_bits(const type_t *tp) 92 { 93 94 lint_assert(is_integer(tp->t_tspec)); 95 return tp->t_bitfield ? tp->t_flen : size_in_bits(tp->t_tspec); 96 } 97 98 static bool 99 ic_maybe_signed(const type_t *tp, const integer_constraints *ic) 100 { 101 102 return !is_uinteger(tp->t_tspec) && 103 (ic->bclr & ((uint64_t)1 << 63)) == 0; 104 } 105 106 static integer_constraints 107 ic_any(const type_t *tp) 108 { 109 integer_constraints c; 110 111 uint64_t vbits = value_bits(width_in_bits(tp)); 112 if (is_uinteger(tp->t_tspec)) { 113 c.smin = INT64_MIN; 114 c.smax = INT64_MAX; 115 c.umin = 0; 116 c.umax = vbits; 117 c.bset = 0; 118 c.bclr = ~c.umax; 119 } else { 120 c.smin = (int64_t)-1 - (int64_t)(vbits >> 1); 121 c.smax = (int64_t)(vbits >> 1); 122 c.umin = 0; 123 c.umax = UINT64_MAX; 124 c.bset = 0; 125 c.bclr = 0; 126 } 127 return c; 128 } 129 130 static integer_constraints 131 ic_con(const type_t *tp, const val_t *v) 132 { 133 integer_constraints c; 134 135 lint_assert(is_integer(tp->t_tspec)); 136 int64_t s = v->v_quad; 137 uint64_t u = (uint64_t)s; 138 c.smin = s; 139 c.smax = s; 140 c.umin = u; 141 c.umax = u; 142 c.bset = u; 143 c.bclr = ~u; 144 return c; 145 } 146 147 static integer_constraints 148 ic_cvt(const type_t *ntp, const type_t *otp, integer_constraints a) 149 { 150 151 if (width_in_bits(ntp) > width_in_bits(otp) && 152 is_uinteger(otp->t_tspec)) 153 return a; 154 return ic_any(ntp); 155 } 156 157 static integer_constraints 158 ic_bitand(integer_constraints a, integer_constraints b) 159 { 160 integer_constraints c; 161 162 c.smin = INT64_MIN; 163 c.smax = INT64_MAX; 164 c.umin = 0; 165 c.umax = UINT64_MAX; 166 c.bset = a.bset & b.bset; 167 c.bclr = a.bclr | b.bclr; 168 return c; 169 } 170 171 static integer_constraints 172 ic_bitor(integer_constraints a, integer_constraints b) 173 { 174 integer_constraints c; 175 176 c.smin = INT64_MIN; 177 c.smax = INT64_MAX; 178 c.umin = 0; 179 c.umax = UINT64_MAX; 180 c.bset = a.bset | b.bset; 181 c.bclr = a.bclr & b.bclr; 182 return c; 183 } 184 185 static integer_constraints 186 ic_mod(const type_t *tp, integer_constraints a, integer_constraints b) 187 { 188 integer_constraints c; 189 190 if (ic_maybe_signed(tp, &a) || ic_maybe_signed(tp, &b)) 191 return ic_any(tp); 192 193 c.smin = INT64_MIN; 194 c.smax = INT64_MAX; 195 c.umin = 0; 196 c.umax = b.umax - 1; 197 c.bset = 0; 198 c.bclr = ~u64_fill_right(c.umax); 199 return c; 200 } 201 202 static integer_constraints 203 ic_shl(const type_t *tp, integer_constraints a, integer_constraints b) 204 { 205 integer_constraints c; 206 unsigned int amount; 207 208 if (ic_maybe_signed(tp, &a)) 209 return ic_any(tp); 210 211 if (b.smin == b.smax && b.smin >= 0 && b.smin < 64) 212 amount = (unsigned int)b.smin; 213 else if (b.umin == b.umax && b.umin < 64) 214 amount = (unsigned int)b.umin; 215 else 216 return ic_any(tp); 217 218 c.smin = INT64_MIN; 219 c.smax = INT64_MAX; 220 c.umin = 0; 221 c.umax = UINT64_MAX; 222 c.bset = a.bset << amount; 223 c.bclr = a.bclr << amount | (((uint64_t)1 << amount) - 1); 224 return c; 225 } 226 227 static integer_constraints 228 ic_shr(const type_t *tp, integer_constraints a, integer_constraints b) 229 { 230 integer_constraints c; 231 unsigned int amount; 232 233 if (ic_maybe_signed(tp, &a)) 234 return ic_any(tp); 235 236 if (b.smin == b.smax && b.smin >= 0 && b.smin < 64) 237 amount = (unsigned int)b.smin; 238 else if (b.umin == b.umax && b.umin < 64) 239 amount = (unsigned int)b.umin; 240 else 241 return ic_any(tp); 242 243 c.smin = INT64_MIN; 244 c.smax = INT64_MAX; 245 c.umin = 0; 246 c.umax = UINT64_MAX; 247 c.bset = a.bset >> amount; 248 c.bclr = a.bclr >> amount | ~(~(uint64_t)0 >> amount); 249 return c; 250 } 251 252 static integer_constraints 253 ic_expr(const tnode_t *tn) 254 { 255 integer_constraints lc, rc; 256 257 lint_assert(is_integer(tn->tn_type->t_tspec)); 258 259 switch (tn->tn_op) { 260 case CON: 261 return ic_con(tn->tn_type, tn->tn_val); 262 case CVT: 263 if (!is_integer(tn->tn_left->tn_type->t_tspec)) 264 return ic_any(tn->tn_type); 265 lc = ic_expr(tn->tn_left); 266 return ic_cvt(tn->tn_type, tn->tn_left->tn_type, lc); 267 case MOD: 268 lc = ic_expr(before_conversion(tn->tn_left)); 269 rc = ic_expr(before_conversion(tn->tn_right)); 270 return ic_mod(tn->tn_type, lc, rc); 271 case SHL: 272 lc = ic_expr(tn->tn_left); 273 rc = ic_expr(tn->tn_right); 274 return ic_shl(tn->tn_type, lc, rc); 275 case SHR: 276 lc = ic_expr(tn->tn_left); 277 rc = ic_expr(tn->tn_right); 278 return ic_shr(tn->tn_type, lc, rc); 279 case BITAND: 280 lc = ic_expr(tn->tn_left); 281 rc = ic_expr(tn->tn_right); 282 return ic_bitand(lc, rc); 283 case BITOR: 284 lc = ic_expr(tn->tn_left); 285 rc = ic_expr(tn->tn_right); 286 return ic_bitor(lc, rc); 287 default: 288 return ic_any(tn->tn_type); 289 } 290 } 291 292 /* Build 'pointer to tp', 'array of tp' or 'function returning tp'. */ 293 type_t * 294 block_derive_type(type_t *tp, tspec_t t) 295 { 296 type_t *tp2; 297 298 tp2 = block_zero_alloc(sizeof(*tp2)); 299 tp2->t_tspec = t; 300 tp2->t_subt = tp; 301 return tp2; 302 } 303 304 /* 305 * Derive 'pointer to tp' or 'function returning tp'. 306 * The memory is freed at the end of the current expression. 307 */ 308 type_t * 309 expr_derive_type(type_t *tp, tspec_t t) 310 { 311 type_t *tp2; 312 313 tp2 = expr_zero_alloc(sizeof(*tp2)); 314 tp2->t_tspec = t; 315 tp2->t_subt = tp; 316 return tp2; 317 } 318 319 /* 320 * Build and initialize a new node. 321 */ 322 static tnode_t * 323 new_tnode(op_t op, bool sys, type_t *type, tnode_t *ln, tnode_t *rn) 324 { 325 326 tnode_t *ntn = expr_alloc_tnode(); 327 ntn->tn_op = op; 328 ntn->tn_type = type; 329 ntn->tn_sys = sys; 330 ntn->tn_left = ln; 331 ntn->tn_right = rn; 332 333 if (op == INDIR || op == FSEL) { 334 lint_assert(ln->tn_type->t_tspec == PTR); 335 tspec_t t = ln->tn_type->t_subt->t_tspec; 336 if (t != FUNC && t != VOID) 337 ntn->tn_lvalue = true; 338 } 339 340 return ntn; 341 } 342 343 /* 344 * Create a node for a constant. 345 */ 346 tnode_t * 347 build_constant(type_t *tp, val_t *v) 348 { 349 tnode_t *n; 350 351 n = expr_alloc_tnode(); 352 n->tn_op = CON; 353 n->tn_type = tp; 354 n->tn_val = expr_zero_alloc(sizeof(*n->tn_val)); 355 n->tn_val->v_tspec = tp->t_tspec; 356 n->tn_val->v_unsigned_since_c90 = v->v_unsigned_since_c90; 357 n->tn_val->v_u = v->v_u; 358 free(v); 359 return n; 360 } 361 362 static tnode_t * 363 build_integer_constant(tspec_t t, int64_t q) 364 { 365 tnode_t *n; 366 367 n = expr_alloc_tnode(); 368 n->tn_op = CON; 369 n->tn_type = gettyp(t); 370 n->tn_val = expr_zero_alloc(sizeof(*n->tn_val)); 371 n->tn_val->v_tspec = t; 372 n->tn_val->v_quad = q; 373 return n; 374 } 375 376 static void 377 fallback_symbol(sym_t *sym) 378 { 379 380 if (Tflag && fallback_symbol_strict_bool(sym)) 381 return; 382 383 if (block_level > 0 && (strcmp(sym->s_name, "__FUNCTION__") == 0 || 384 strcmp(sym->s_name, "__PRETTY_FUNCTION__") == 0)) { 385 /* __FUNCTION__/__PRETTY_FUNCTION__ is a GCC extension */ 386 gnuism(316); 387 sym->s_type = block_derive_type(gettyp(CHAR), PTR); 388 sym->s_type->t_const = true; 389 return; 390 } 391 392 if (block_level > 0 && strcmp(sym->s_name, "__func__") == 0) { 393 if (!allow_c99) 394 /* __func__ is a C99 feature */ 395 warning(317); 396 /* C11 6.4.2.2 */ 397 sym->s_type = block_derive_type(gettyp(CHAR), ARRAY); 398 sym->s_type->t_const = true; 399 sym->s_type->t_dim = (int)strlen(funcsym->s_name) + 1; 400 return; 401 } 402 403 /* '%s' undefined */ 404 error(99, sym->s_name); 405 } 406 407 /* 408 * Functions that are predeclared by GCC or other compilers can be called 409 * with arbitrary arguments. Since lint usually runs after a successful 410 * compilation, it's the compiler's job to catch any errors. 411 */ 412 bool 413 is_compiler_builtin(const char *name) 414 { 415 /* https://gcc.gnu.org/onlinedocs/gcc/C-Extensions.html */ 416 if (allow_gcc) { 417 if (strncmp(name, "__atomic_", 9) == 0 || 418 strncmp(name, "__builtin_", 10) == 0 || 419 strcmp(name, "alloca") == 0 || 420 /* obsolete but still in use, as of 2021 */ 421 strncmp(name, "__sync_", 7) == 0) 422 return true; 423 } 424 425 /* https://software.intel.com/sites/landingpage/IntrinsicsGuide/ */ 426 if (strncmp(name, "_mm_", 4) == 0) 427 return true; 428 429 return false; 430 } 431 432 /* https://gcc.gnu.org/onlinedocs/gcc/Integer-Overflow-Builtins.html */ 433 static bool 434 is_gcc_bool_builtin(const char *name) 435 { 436 return strncmp(name, "__builtin_", 10) == 0 && 437 (str_endswith(name, "_overflow") || 438 str_endswith(name, "_overflow_p")); 439 } 440 441 static void 442 build_name_call(sym_t *sym) 443 { 444 445 if (is_compiler_builtin(sym->s_name)) { 446 /* 447 * Do not warn about these, just assume that 448 * they are regular functions compatible with 449 * non-prototype calling conventions. 450 */ 451 if (allow_gcc && is_gcc_bool_builtin(sym->s_name)) 452 sym->s_type = gettyp(BOOL); 453 454 } else if (allow_c99) { 455 /* function '%s' implicitly declared to return int */ 456 error(215, sym->s_name); 457 } else if (!allow_trad) { 458 /* function '%s' implicitly declared to return int */ 459 warning(215, sym->s_name); 460 } 461 462 /* XXX if !allow_c90, the symbol should be exported to level 0 */ 463 sym->s_type = block_derive_type(sym->s_type, FUNC); 464 } 465 466 /* Create a node for a name (symbol table entry). */ 467 tnode_t * 468 build_name(sym_t *sym, bool is_funcname) 469 { 470 tnode_t *n; 471 472 if (sym->s_scl == NOSCL && !in_gcc_attribute) { 473 sym->s_scl = EXTERN; 474 sym->s_def = DECL; 475 if (is_funcname) 476 build_name_call(sym); 477 else 478 fallback_symbol(sym); 479 } 480 481 lint_assert(sym->s_kind == FVFT || sym->s_kind == FMEMBER); 482 483 n = expr_alloc_tnode(); 484 n->tn_type = sym->s_type; 485 if (sym->s_scl == BOOL_CONST) { 486 n->tn_op = CON; 487 n->tn_val = expr_zero_alloc(sizeof(*n->tn_val)); 488 n->tn_val->v_tspec = BOOL; 489 n->tn_val->v_quad = sym->u.s_bool_constant ? 1 : 0; 490 } else if (sym->s_scl == ENUM_CONST) { 491 n->tn_op = CON; 492 n->tn_val = expr_zero_alloc(sizeof(*n->tn_val)); 493 n->tn_val->v_tspec = INT; /* ENUM is in n->tn_type */ 494 n->tn_val->v_quad = sym->u.s_enum_constant; 495 } else { 496 n->tn_op = NAME; 497 n->tn_sym = sym; 498 if (sym->s_kind == FVFT && sym->s_type->t_tspec != FUNC) 499 n->tn_lvalue = true; 500 } 501 502 return n; 503 } 504 505 tnode_t * 506 build_string(strg_t *strg) 507 { 508 size_t len; 509 tnode_t *n; 510 type_t *tp; 511 512 len = strg->st_len; 513 514 n = expr_alloc_tnode(); 515 516 tp = expr_zero_alloc(sizeof(*tp)); 517 tp->t_tspec = ARRAY; 518 tp->t_subt = gettyp(strg->st_char ? CHAR : WCHAR); 519 tp->t_dim = (int)(len + 1); 520 521 n->tn_op = STRING; 522 n->tn_type = tp; 523 n->tn_lvalue = true; 524 525 n->tn_string = expr_zero_alloc(sizeof(*n->tn_string)); 526 n->tn_string->st_char = strg->st_char; 527 n->tn_string->st_len = len; 528 529 size_t chsize = strg->st_char ? sizeof(char) : sizeof(wchar_t); 530 size_t size = (len + 1) * chsize; 531 n->tn_string->st_mem = expr_zero_alloc(size); 532 (void)memcpy(n->tn_string->st_mem, strg->st_mem, size); 533 free(strg->st_mem); 534 free(strg); 535 536 return n; 537 } 538 539 tnode_t * 540 build_generic_selection(const tnode_t *expr, 541 struct generic_association *sel) 542 { 543 tnode_t *default_result = NULL; 544 545 for (; sel != NULL; sel = sel->ga_prev) { 546 if (expr != NULL && 547 types_compatible(sel->ga_arg, expr->tn_type, 548 false, false, NULL)) 549 return sel->ga_result; 550 else if (sel->ga_arg == NULL) 551 default_result = sel->ga_result; 552 } 553 return default_result; 554 } 555 556 static bool 557 is_out_of_char_range(const tnode_t *tn) 558 { 559 return tn->tn_op == CON && 560 !(0 <= tn->tn_val->v_quad && 561 tn->tn_val->v_quad < 1 << (CHAR_SIZE - 1)); 562 } 563 564 /* 565 * Check for ordered comparisons of unsigned values with 0. 566 */ 567 static void 568 check_integer_comparison(op_t op, tnode_t *ln, tnode_t *rn) 569 { 570 tspec_t lt, rt; 571 572 lt = ln->tn_type->t_tspec; 573 rt = rn->tn_type->t_tspec; 574 575 if (ln->tn_op != CON && rn->tn_op != CON) 576 return; 577 578 if (!is_integer(lt) || !is_integer(rt)) 579 return; 580 581 if (hflag || pflag) { 582 if (lt == CHAR && is_out_of_char_range(rn)) { 583 char buf[128]; 584 (void)snprintf(buf, sizeof(buf), "%s %d", 585 op_name(op), (int)rn->tn_val->v_quad); 586 /* nonportable character comparison '%s' */ 587 warning(230, buf); 588 return; 589 } 590 if (rt == CHAR && is_out_of_char_range(ln)) { 591 char buf[128]; 592 (void)snprintf(buf, sizeof(buf), "%d %s ?", 593 (int)ln->tn_val->v_quad, op_name(op)); 594 /* nonportable character comparison '%s' */ 595 warning(230, buf); 596 return; 597 } 598 } 599 600 if (is_uinteger(lt) && !is_uinteger(rt) && 601 rn->tn_op == CON && rn->tn_val->v_quad <= 0) { 602 if (rn->tn_val->v_quad < 0) { 603 /* operator '%s' compares '%s' with '%s' */ 604 warning(162, op_name(op), 605 type_name(ln->tn_type), "negative constant"); 606 } else if (op == LT || op == GE) { 607 /* operator '%s' compares '%s' with '%s' */ 608 warning(162, op_name(op), type_name(ln->tn_type), "0"); 609 } 610 return; 611 } 612 if (is_uinteger(rt) && !is_uinteger(lt) && 613 ln->tn_op == CON && ln->tn_val->v_quad <= 0) { 614 if (ln->tn_val->v_quad < 0) { 615 /* operator '%s' compares '%s' with '%s' */ 616 warning(162, op_name(op), 617 "negative constant", type_name(rn->tn_type)); 618 } else if (op == GT || op == LE) { 619 /* operator '%s' compares '%s' with '%s' */ 620 warning(162, op_name(op), "0", type_name(rn->tn_type)); 621 } 622 return; 623 } 624 } 625 626 static const tspec_t arith_rank[] = { 627 LDOUBLE, DOUBLE, FLOAT, 628 #ifdef INT128_SIZE 629 UINT128, INT128, 630 #endif 631 UQUAD, QUAD, 632 ULONG, LONG, 633 UINT, INT, 634 }; 635 636 /* Keep unsigned in traditional C */ 637 static tspec_t 638 usual_arithmetic_conversion_trad(tspec_t lt, tspec_t rt) 639 { 640 641 size_t i; 642 for (i = 0; arith_rank[i] != INT; i++) 643 if (lt == arith_rank[i] || rt == arith_rank[i]) 644 break; 645 646 tspec_t t = arith_rank[i]; 647 if (is_uinteger(lt) || is_uinteger(rt)) 648 if (is_integer(t) && !is_uinteger(t)) 649 return unsigned_type(t); 650 return t; 651 } 652 653 static tspec_t 654 usual_arithmetic_conversion_c90(tspec_t lt, tspec_t rt) 655 { 656 657 if (lt == rt) 658 return lt; 659 660 if (lt == LCOMPLEX || rt == LCOMPLEX) 661 return LCOMPLEX; 662 if (lt == DCOMPLEX || rt == DCOMPLEX) 663 return DCOMPLEX; 664 if (lt == FCOMPLEX || rt == FCOMPLEX) 665 return FCOMPLEX; 666 if (lt == LDOUBLE || rt == LDOUBLE) 667 return LDOUBLE; 668 if (lt == DOUBLE || rt == DOUBLE) 669 return DOUBLE; 670 if (lt == FLOAT || rt == FLOAT) 671 return FLOAT; 672 673 /* 674 * If type A has more bits than type B, it should be able to hold all 675 * possible values of type B. 676 */ 677 if (size_in_bits(lt) > size_in_bits(rt)) 678 return lt; 679 if (size_in_bits(lt) < size_in_bits(rt)) 680 return rt; 681 682 size_t i; 683 for (i = 3; arith_rank[i] != INT; i++) 684 if (arith_rank[i] == lt || arith_rank[i] == rt) 685 break; 686 if ((is_uinteger(lt) || is_uinteger(rt)) && 687 !is_uinteger(arith_rank[i])) 688 i--; 689 return arith_rank[i]; 690 } 691 692 static tnode_t * 693 apply_usual_arithmetic_conversions(op_t op, tnode_t *tn, tspec_t t) 694 { 695 type_t *ntp = expr_dup_type(tn->tn_type); 696 ntp->t_tspec = t; 697 if (tn->tn_op != CON) { 698 /* usual arithmetic conversion for '%s' from '%s' to '%s' */ 699 query_message(4, op_name(op), 700 type_name(tn->tn_type), type_name(ntp)); 701 } 702 return convert(op, 0, ntp, tn); 703 } 704 705 /* 706 * Apply the "usual arithmetic conversions" (C99 6.3.1.8), which gives both 707 * operands the same type. 708 */ 709 static void 710 balance(op_t op, tnode_t **lnp, tnode_t **rnp) 711 { 712 713 tspec_t lt = (*lnp)->tn_type->t_tspec; 714 tspec_t rt = (*rnp)->tn_type->t_tspec; 715 if (!is_arithmetic(lt) || !is_arithmetic(rt)) 716 return; 717 718 tspec_t t = allow_c90 719 ? usual_arithmetic_conversion_c90(lt, rt) 720 : usual_arithmetic_conversion_trad(lt, rt); 721 722 if (t != lt) 723 *lnp = apply_usual_arithmetic_conversions(op, *lnp, t); 724 if (t != rt) 725 *rnp = apply_usual_arithmetic_conversions(op, *rnp, t); 726 } 727 728 /* 729 * Create a tree node for the unary & operator 730 */ 731 static tnode_t * 732 build_address(bool sys, tnode_t *tn, bool noign) 733 { 734 tspec_t t; 735 736 if (!noign && ((t = tn->tn_type->t_tspec) == ARRAY || t == FUNC)) { 737 if (!allow_c90) 738 /* '&' before array or function: ignored */ 739 warning(127); 740 return tn; 741 } 742 743 /* eliminate &* */ 744 if (tn->tn_op == INDIR && 745 tn->tn_left->tn_type->t_tspec == PTR && 746 tn->tn_left->tn_type->t_subt == tn->tn_type) { 747 return tn->tn_left; 748 } 749 750 return new_tnode(ADDR, sys, expr_derive_type(tn->tn_type, PTR), 751 tn, NULL); 752 } 753 754 /* 755 * XXX 756 * Note: There appear to be a number of bugs in detecting overflow in 757 * this function. An audit and a set of proper regression tests are needed. 758 * --Perry Metzger, Nov. 16, 2001 759 */ 760 /* 761 * Do only as much as necessary to compute constant expressions. 762 * Called only if the operator allows folding and all operands are constants. 763 */ 764 static tnode_t * 765 fold(tnode_t *tn) 766 { 767 val_t *v; 768 tspec_t t; 769 bool utyp, ovfl; 770 int64_t sl, sr = 0, q = 0, mask; 771 uint64_t ul, ur = 0; 772 tnode_t *cn; 773 774 v = xcalloc(1, sizeof(*v)); 775 v->v_tspec = tn->tn_type->t_tspec; 776 777 t = tn->tn_left->tn_type->t_tspec; 778 utyp = !is_integer(t) || is_uinteger(t); 779 ul = sl = tn->tn_left->tn_val->v_quad; 780 if (is_binary(tn)) 781 ur = sr = tn->tn_right->tn_val->v_quad; 782 783 mask = value_bits(size_in_bits(t)); 784 ovfl = false; 785 786 switch (tn->tn_op) { 787 case UPLUS: 788 q = sl; 789 break; 790 case UMINUS: 791 q = sl == INT64_MIN ? sl : -sl; 792 if (sl != 0 && msb(q, t) == msb(sl, t)) 793 ovfl = true; 794 break; 795 case COMPL: 796 q = ~sl; 797 break; 798 case MULT: 799 if (utyp) { 800 q = ul * ur; 801 if (q != (q & mask)) 802 ovfl = true; 803 else if ((ul != 0) && ((q / ul) != ur)) 804 ovfl = true; 805 } else { 806 q = sl * sr; 807 if (msb(q, t) != (msb(sl, t) ^ msb(sr, t))) 808 ovfl = true; 809 } 810 break; 811 case DIV: 812 if (sr == 0) { 813 /* division by 0 */ 814 error(139); 815 q = utyp ? -1 : INT64_MAX; 816 } else { 817 q = utyp ? (int64_t)(ul / ur) : sl / sr; 818 } 819 break; 820 case MOD: 821 if (sr == 0) { 822 /* modulus by 0 */ 823 error(140); 824 q = 0; 825 } else { 826 q = utyp ? (int64_t)(ul % ur) : sl % sr; 827 } 828 break; 829 case PLUS: 830 q = utyp ? (int64_t)(ul + ur) : sl + sr; 831 if (msb(sl, t) && msb(sr, t) && !msb(q, t)) 832 ovfl = true; 833 if (!utyp && !msb(sl, t) && !msb(sr, t) && msb(q, t)) 834 ovfl = true; 835 break; 836 case MINUS: 837 q = utyp ? (int64_t)(ul - ur) : sl - sr; 838 if (!utyp && msb(sl, t) && !msb(sr, t) && !msb(q, t)) 839 ovfl = true; 840 if (!msb(sl, t) && msb(sr, t) && msb(q, t)) 841 ovfl = true; 842 break; 843 case SHL: 844 /* TODO: warn about out-of-bounds 'sr'. */ 845 /* TODO: warn about overflow in signed '<<'. */ 846 q = utyp ? (int64_t)(ul << (sr & 63)) : sl << (sr & 63); 847 break; 848 case SHR: 849 /* 850 * The sign must be explicitly extended because 851 * shifts of signed values are implementation dependent. 852 */ 853 /* TODO: warn about out-of-bounds 'sr'. */ 854 q = ul >> (sr & 63); 855 q = convert_integer(q, t, size_in_bits(t) - (int)sr); 856 break; 857 case LT: 858 q = (utyp ? ul < ur : sl < sr) ? 1 : 0; 859 break; 860 case LE: 861 q = (utyp ? ul <= ur : sl <= sr) ? 1 : 0; 862 break; 863 case GE: 864 q = (utyp ? ul >= ur : sl >= sr) ? 1 : 0; 865 break; 866 case GT: 867 q = (utyp ? ul > ur : sl > sr) ? 1 : 0; 868 break; 869 case EQ: 870 q = (utyp ? ul == ur : sl == sr) ? 1 : 0; 871 break; 872 case NE: 873 q = (utyp ? ul != ur : sl != sr) ? 1 : 0; 874 break; 875 case BITAND: 876 q = utyp ? (int64_t)(ul & ur) : sl & sr; 877 break; 878 case BITXOR: 879 q = utyp ? (int64_t)(ul ^ ur) : sl ^ sr; 880 break; 881 case BITOR: 882 q = utyp ? (int64_t)(ul | ur) : sl | sr; 883 break; 884 default: 885 lint_assert(/*CONSTCOND*/false); 886 } 887 888 /* XXX does not work for quads. */ 889 if (ovfl || 890 ((uint64_t)(q | mask) != ~(uint64_t)0 && (q & ~mask) != 0)) { 891 if (hflag) 892 /* integer overflow detected, op '%s' */ 893 warning(141, op_name(tn->tn_op)); 894 } 895 896 v->v_quad = convert_integer(q, t, 0); 897 898 cn = build_constant(tn->tn_type, v); 899 if (tn->tn_left->tn_system_dependent) 900 cn->tn_system_dependent = true; 901 if (is_binary(tn) && tn->tn_right->tn_system_dependent) 902 cn->tn_system_dependent = true; 903 904 return cn; 905 } 906 907 /* 908 * Create a new node for one of the operators POINT and ARROW. 909 */ 910 static tnode_t * 911 build_struct_access(op_t op, bool sys, tnode_t *ln, tnode_t *rn) 912 { 913 tnode_t *ntn, *ctn; 914 bool nolval; 915 916 lint_assert(rn->tn_op == NAME); 917 lint_assert(is_member(rn->tn_sym)); 918 919 /* 920 * Remember if the left operand is an lvalue (structure members 921 * are lvalues if and only if the structure itself is an lvalue). 922 */ 923 nolval = op == POINT && !ln->tn_lvalue; 924 925 if (op == POINT) { 926 ln = build_address(sys, ln, true); 927 } else if (ln->tn_type->t_tspec != PTR) { 928 lint_assert(!allow_c90); 929 lint_assert(is_integer(ln->tn_type->t_tspec)); 930 ln = convert(NOOP, 0, expr_derive_type(gettyp(VOID), PTR), ln); 931 } 932 933 ctn = build_integer_constant(PTRDIFF_TSPEC, 934 rn->tn_sym->u.s_member.sm_offset_in_bits / CHAR_SIZE); 935 936 ntn = new_tnode(PLUS, sys, expr_derive_type(rn->tn_type, PTR), 937 ln, ctn); 938 if (ln->tn_op == CON) 939 ntn = fold(ntn); 940 941 if (rn->tn_type->t_bitfield) { 942 ntn = new_tnode(FSEL, sys, ntn->tn_type->t_subt, ntn, NULL); 943 } else { 944 ntn = new_tnode(INDIR, sys, ntn->tn_type->t_subt, ntn, NULL); 945 } 946 947 if (nolval) 948 ntn->tn_lvalue = false; 949 950 return ntn; 951 } 952 953 /* 954 * Get the size in bytes of type tp->t_subt, as a constant expression of type 955 * ptrdiff_t as seen from the target platform. 956 */ 957 static tnode_t * 958 subt_size_in_bytes(type_t *tp) 959 { 960 int elem, elsz_in_bits; 961 962 lint_assert(tp->t_tspec == PTR); 963 tp = tp->t_subt; 964 965 elem = 1; 966 elsz_in_bits = 0; 967 968 while (tp->t_tspec == ARRAY) { 969 elem *= tp->t_dim; 970 tp = tp->t_subt; 971 } 972 973 switch (tp->t_tspec) { 974 case FUNC: 975 /* pointer to function is not allowed here */ 976 error(110); 977 break; 978 case VOID: 979 /* cannot do pointer arithmetic on operand of unknown size */ 980 gnuism(136); 981 break; 982 case STRUCT: 983 case UNION: 984 if ((elsz_in_bits = tp->t_str->sou_size_in_bits) == 0) 985 /* cannot do pointer arithmetic on operand of ... */ 986 error(136); 987 break; 988 case ENUM: 989 if (is_incomplete(tp)) { 990 /* cannot do pointer arithmetic on operand of ... */ 991 warning(136); 992 } 993 /* FALLTHROUGH */ 994 default: 995 if ((elsz_in_bits = size_in_bits(tp->t_tspec)) == 0) { 996 /* cannot do pointer arithmetic on operand of ... */ 997 error(136); 998 } else { 999 lint_assert(elsz_in_bits != -1); 1000 } 1001 break; 1002 } 1003 1004 if (elem == 0 && elsz_in_bits != 0) { 1005 /* cannot do pointer arithmetic on operand of unknown size */ 1006 error(136); 1007 } 1008 1009 if (elsz_in_bits == 0) 1010 elsz_in_bits = CHAR_SIZE; 1011 1012 return build_integer_constant(PTRDIFF_TSPEC, 1013 (int64_t)(elem * elsz_in_bits / CHAR_SIZE)); 1014 } 1015 1016 /* 1017 * Create a node for INCAFT, INCBEF, DECAFT and DECBEF. 1018 */ 1019 static tnode_t * 1020 build_prepost_incdec(op_t op, bool sys, tnode_t *ln) 1021 { 1022 tnode_t *cn, *ntn; 1023 1024 lint_assert(ln != NULL); 1025 1026 if (ln->tn_type->t_tspec == PTR) { 1027 cn = subt_size_in_bytes(ln->tn_type); 1028 } else { 1029 cn = build_integer_constant(INT, (int64_t)1); 1030 } 1031 ntn = new_tnode(op, sys, ln->tn_type, ln, cn); 1032 1033 return ntn; 1034 } 1035 1036 static void 1037 check_enum_array_index(const tnode_t *ln, const tnode_t *rn) 1038 { 1039 int max_array_index; 1040 int64_t max_enum_value; 1041 const struct sym *ec, *max_ec; 1042 const type_t *lt, *rt; 1043 1044 if (ln->tn_op != ADDR || ln->tn_left->tn_op != NAME) 1045 return; 1046 1047 lt = ln->tn_left->tn_type; 1048 if (lt->t_tspec != ARRAY || lt->t_incomplete_array) 1049 return; 1050 1051 if (rn->tn_op != CVT || !rn->tn_type->t_is_enum) 1052 return; 1053 if (rn->tn_left->tn_op != LOAD) 1054 return; 1055 1056 rt = rn->tn_left->tn_type; 1057 ec = rt->t_enum->en_first_enumerator; 1058 max_ec = ec; 1059 lint_assert(ec != NULL); 1060 for (ec = ec->s_next; ec != NULL; ec = ec->s_next) 1061 if (ec->u.s_enum_constant > max_ec->u.s_enum_constant) 1062 max_ec = ec; 1063 1064 max_enum_value = max_ec->u.s_enum_constant; 1065 lint_assert(INT_MIN <= max_enum_value && max_enum_value <= INT_MAX); 1066 1067 max_array_index = lt->t_dim - 1; 1068 if (max_enum_value == max_array_index) 1069 return; 1070 1071 /* 1072 * If the name of the largest enum constant contains 'MAX' or 'NUM', 1073 * that constant is typically not part of the allowed enum values but 1074 * a marker for the number of actual enum values. 1075 */ 1076 if (max_enum_value == max_array_index + 1 && 1077 (strstr(max_ec->s_name, "MAX") != NULL || 1078 strstr(max_ec->s_name, "max") != NULL || 1079 strstr(max_ec->s_name, "NUM") != NULL || 1080 strstr(max_ec->s_name, "num") != NULL)) 1081 return; 1082 1083 /* maximum value %d of '%s' does not match maximum array index %d */ 1084 warning(348, (int)max_enum_value, type_name(rt), max_array_index); 1085 print_previous_declaration(max_ec); 1086 } 1087 1088 /* 1089 * Create a node for operators PLUS and MINUS. 1090 */ 1091 static tnode_t * 1092 build_plus_minus(op_t op, bool sys, tnode_t *ln, tnode_t *rn) 1093 { 1094 1095 /* If pointer and integer, then pointer to the lhs. */ 1096 if (rn->tn_type->t_tspec == PTR && is_integer(ln->tn_type->t_tspec)) { 1097 tnode_t *tmp = ln; 1098 ln = rn; 1099 rn = tmp; 1100 /* pointer addition has integer on the left-hand side */ 1101 query_message(5); 1102 } 1103 1104 /* pointer +- integer */ 1105 if (ln->tn_type->t_tspec == PTR && rn->tn_type->t_tspec != PTR) { 1106 lint_assert(is_integer(rn->tn_type->t_tspec)); 1107 1108 check_ctype_macro_invocation(ln, rn); 1109 check_enum_array_index(ln, rn); 1110 1111 tnode_t *elsz = subt_size_in_bytes(ln->tn_type); 1112 if (rn->tn_type->t_tspec != elsz->tn_type->t_tspec) 1113 rn = convert(NOOP, 0, elsz->tn_type, rn); 1114 1115 tnode_t *prod = new_tnode(MULT, sys, rn->tn_type, rn, elsz); 1116 if (rn->tn_op == CON) 1117 prod = fold(prod); 1118 1119 return new_tnode(op, sys, ln->tn_type, ln, prod); 1120 } 1121 1122 /* pointer - pointer */ 1123 if (rn->tn_type->t_tspec == PTR) { 1124 lint_assert(ln->tn_type->t_tspec == PTR); 1125 lint_assert(op == MINUS); 1126 1127 type_t *ptrdiff = gettyp(PTRDIFF_TSPEC); 1128 tnode_t *raw_diff = new_tnode(op, sys, ptrdiff, ln, rn); 1129 if (ln->tn_op == CON && rn->tn_op == CON) 1130 raw_diff = fold(raw_diff); 1131 1132 tnode_t *elsz = subt_size_in_bytes(ln->tn_type); 1133 balance(NOOP, &raw_diff, &elsz); 1134 1135 return new_tnode(DIV, sys, ptrdiff, raw_diff, elsz); 1136 } 1137 1138 return new_tnode(op, sys, ln->tn_type, ln, rn); 1139 } 1140 1141 /* 1142 * Create a node for operators SHL and SHR. 1143 */ 1144 static tnode_t * 1145 build_bit_shift(op_t op, bool sys, tnode_t *ln, tnode_t *rn) 1146 { 1147 1148 if (!allow_c90 && rn->tn_type->t_tspec != INT) 1149 rn = convert(NOOP, 0, gettyp(INT), rn); 1150 return new_tnode(op, sys, ln->tn_type, ln, rn); 1151 } 1152 1153 static bool 1154 is_null_pointer(const tnode_t *tn) 1155 { 1156 tspec_t t = tn->tn_type->t_tspec; 1157 1158 return ((t == PTR && tn->tn_type->t_subt->t_tspec == VOID) || 1159 is_integer(t)) 1160 && (tn->tn_op == CON && tn->tn_val->v_quad == 0); 1161 } 1162 1163 /* Return a type based on tp1, with added qualifiers from tp2. */ 1164 static type_t * 1165 merge_qualifiers(type_t *tp1, const type_t *tp2) 1166 { 1167 type_t *ntp, *nstp; 1168 bool c1, c2, v1, v2; 1169 1170 lint_assert(tp1->t_tspec == PTR); 1171 lint_assert(tp2->t_tspec == PTR); 1172 1173 c1 = tp1->t_subt->t_const; 1174 c2 = tp2->t_subt->t_const; 1175 v1 = tp1->t_subt->t_volatile; 1176 v2 = tp2->t_subt->t_volatile; 1177 1178 if (c1 == (c1 | c2) && v1 == (v1 | v2)) 1179 return tp1; 1180 1181 nstp = expr_dup_type(tp1->t_subt); 1182 nstp->t_const |= c2; 1183 nstp->t_volatile |= v2; 1184 1185 ntp = expr_dup_type(tp1); 1186 ntp->t_subt = nstp; 1187 return ntp; 1188 } 1189 1190 /* See C99 6.5.15 "Conditional operator". */ 1191 static tnode_t * 1192 build_colon(bool sys, tnode_t *ln, tnode_t *rn) 1193 { 1194 tspec_t lt, rt; 1195 type_t *tp; 1196 1197 lt = ln->tn_type->t_tspec; 1198 rt = rn->tn_type->t_tspec; 1199 1200 if (is_arithmetic(lt) && is_arithmetic(rt)) { 1201 /* The operands were already balanced in build_binary. */ 1202 tp = ln->tn_type; 1203 } else if (lt == BOOL && rt == BOOL) { 1204 tp = ln->tn_type; 1205 } else if (lt == VOID || rt == VOID) { 1206 tp = gettyp(VOID); 1207 } else if (is_struct_or_union(lt)) { 1208 /* Both types must be identical. */ 1209 lint_assert(is_struct_or_union(rt)); 1210 lint_assert(ln->tn_type->t_str == rn->tn_type->t_str); 1211 if (is_incomplete(ln->tn_type)) { 1212 /* unknown operand size, op '%s' */ 1213 error(138, op_name(COLON)); 1214 return NULL; 1215 } 1216 tp = ln->tn_type; 1217 } else if (lt == PTR && is_integer(rt)) { 1218 if (rt != PTRDIFF_TSPEC) 1219 rn = convert(NOOP, 0, gettyp(PTRDIFF_TSPEC), rn); 1220 tp = ln->tn_type; 1221 } else if (rt == PTR && is_integer(lt)) { 1222 if (lt != PTRDIFF_TSPEC) 1223 ln = convert(NOOP, 0, gettyp(PTRDIFF_TSPEC), ln); 1224 tp = rn->tn_type; 1225 } else if (lt == PTR && is_null_pointer(rn)) { 1226 tp = merge_qualifiers(ln->tn_type, rn->tn_type); 1227 } else if (rt == PTR && is_null_pointer(ln)) { 1228 tp = merge_qualifiers(rn->tn_type, ln->tn_type); 1229 } else if (lt == PTR && ln->tn_type->t_subt->t_tspec == VOID) { 1230 tp = merge_qualifiers(ln->tn_type, rn->tn_type); 1231 } else if (rt == PTR && rn->tn_type->t_subt->t_tspec == VOID) { 1232 tp = merge_qualifiers(rn->tn_type, ln->tn_type); 1233 } else { 1234 /* 1235 * XXX For now we simply take the left type. This is 1236 * probably wrong, if one type contains a function prototype 1237 * and the other one, at the same place, only an old-style 1238 * declaration. 1239 */ 1240 tp = merge_qualifiers(ln->tn_type, rn->tn_type); 1241 } 1242 1243 return new_tnode(COLON, sys, tp, ln, rn); 1244 } 1245 1246 /* TODO: check for varargs */ 1247 static bool 1248 is_cast_redundant(const tnode_t *tn) 1249 { 1250 const type_t *ntp = tn->tn_type, *otp = tn->tn_left->tn_type; 1251 tspec_t nt = ntp->t_tspec, ot = otp->t_tspec; 1252 1253 if (nt == BOOL || ot == BOOL) 1254 return nt == BOOL && ot == BOOL; 1255 1256 if (is_integer(nt) && is_integer(ot)) { 1257 unsigned int nw = width_in_bits(ntp), ow = width_in_bits(otp); 1258 if (is_uinteger(nt) == is_uinteger(ot)) 1259 return nw >= ow; 1260 return is_uinteger(ot) && nw > ow; 1261 } 1262 1263 if (is_complex(nt) || is_complex(ot)) 1264 return is_complex(nt) && is_complex(ot) && 1265 size_in_bits(nt) >= size_in_bits(ot); 1266 1267 if (is_floating(nt) && is_floating(ot)) 1268 return size_in_bits(nt) >= size_in_bits(ot); 1269 1270 if (nt == PTR && ot == PTR) { 1271 if (!ntp->t_subt->t_const && otp->t_subt->t_const) 1272 return false; 1273 if (!ntp->t_subt->t_volatile && otp->t_subt->t_volatile) 1274 return false; 1275 1276 if (ntp->t_subt->t_tspec == VOID || 1277 otp->t_subt->t_tspec == VOID || 1278 types_compatible(ntp->t_subt, otp->t_subt, 1279 false, false, NULL)) 1280 return true; 1281 } 1282 1283 return false; 1284 } 1285 1286 /* 1287 * Create a node for an assignment operator (both = and op= ). 1288 */ 1289 static tnode_t * 1290 build_assignment(op_t op, bool sys, tnode_t *ln, tnode_t *rn) 1291 { 1292 tspec_t lt, rt; 1293 tnode_t *ntn, *ctn; 1294 1295 lint_assert(ln != NULL); 1296 lint_assert(rn != NULL); 1297 1298 lt = ln->tn_type->t_tspec; 1299 rt = rn->tn_type->t_tspec; 1300 1301 if ((op == ADDASS || op == SUBASS) && lt == PTR) { 1302 lint_assert(is_integer(rt)); 1303 ctn = subt_size_in_bytes(ln->tn_type); 1304 if (rn->tn_type->t_tspec != ctn->tn_type->t_tspec) 1305 rn = convert(NOOP, 0, ctn->tn_type, rn); 1306 rn = new_tnode(MULT, sys, rn->tn_type, rn, ctn); 1307 if (rn->tn_left->tn_op == CON) 1308 rn = fold(rn); 1309 } 1310 1311 if ((op == ASSIGN || op == RETURN || op == INIT) && 1312 (lt == STRUCT || rt == STRUCT)) { 1313 lint_assert(lt == rt); 1314 lint_assert(ln->tn_type->t_str == rn->tn_type->t_str); 1315 if (is_incomplete(ln->tn_type)) { 1316 if (op == RETURN) { 1317 /* cannot return incomplete type */ 1318 error(212); 1319 } else { 1320 /* unknown operand size, op '%s' */ 1321 error(138, op_name(op)); 1322 } 1323 return NULL; 1324 } 1325 } 1326 1327 if (op == SHLASS) { 1328 if (portable_size_in_bits(lt) < portable_size_in_bits(rt)) { 1329 if (hflag) 1330 /* semantics of '%s' change in ANSI C; ... */ 1331 warning(118, "<<="); 1332 } 1333 } else if (op != SHRASS) { 1334 if (op == ASSIGN || lt != PTR) { 1335 if (lt != rt || 1336 (ln->tn_type->t_bitfield && rn->tn_op == CON)) { 1337 rn = convert(op, 0, ln->tn_type, rn); 1338 rt = lt; 1339 } 1340 } 1341 } 1342 1343 if (any_query_enabled && rn->tn_op == CVT && rn->tn_cast && 1344 types_compatible(ln->tn_type, rn->tn_type, false, false, NULL) && 1345 is_cast_redundant(rn)) { 1346 /* redundant cast from '%s' to '%s' before assignment */ 1347 query_message(7, 1348 type_name(rn->tn_left->tn_type), type_name(rn->tn_type)); 1349 } 1350 1351 ntn = new_tnode(op, sys, ln->tn_type, ln, rn); 1352 1353 return ntn; 1354 } 1355 1356 /* 1357 * Create a node for REAL, IMAG 1358 */ 1359 static tnode_t * 1360 build_real_imag(op_t op, bool sys, tnode_t *ln) 1361 { 1362 tnode_t *cn, *ntn; 1363 1364 lint_assert(ln != NULL); 1365 1366 if (ln->tn_op == NAME) { 1367 /* 1368 * This may be too much, but it avoids wrong warnings. 1369 * See d_c99_complex_split.c. 1370 */ 1371 mark_as_used(ln->tn_sym, false, false); 1372 mark_as_set(ln->tn_sym); 1373 } 1374 1375 switch (ln->tn_type->t_tspec) { 1376 case LCOMPLEX: 1377 /* XXX: integer and LDOUBLE don't match. */ 1378 cn = build_integer_constant(LDOUBLE, (int64_t)1); 1379 break; 1380 case DCOMPLEX: 1381 /* XXX: integer and DOUBLE don't match. */ 1382 cn = build_integer_constant(DOUBLE, (int64_t)1); 1383 break; 1384 case FCOMPLEX: 1385 /* XXX: integer and FLOAT don't match. */ 1386 cn = build_integer_constant(FLOAT, (int64_t)1); 1387 break; 1388 default: 1389 /* '__%s__' is illegal for type '%s' */ 1390 error(276, op == REAL ? "real" : "imag", 1391 type_name(ln->tn_type)); 1392 return NULL; 1393 } 1394 ntn = new_tnode(op, sys, cn->tn_type, ln, cn); 1395 ntn->tn_lvalue = true; 1396 1397 return ntn; 1398 } 1399 1400 static bool 1401 is_confusing_precedence(op_t op, op_t lop, bool lparen, op_t rop, bool rparen) 1402 { 1403 1404 if (op == SHL || op == SHR) { 1405 if (!lparen && (lop == PLUS || lop == MINUS)) 1406 return true; 1407 if (!rparen && (rop == PLUS || rop == MINUS)) 1408 return true; 1409 return false; 1410 } 1411 1412 if (op == LOGOR) { 1413 if (!lparen && lop == LOGAND) 1414 return true; 1415 if (!rparen && rop == LOGAND) 1416 return true; 1417 return false; 1418 } 1419 1420 lint_assert(op == BITAND || op == BITXOR || op == BITOR); 1421 if (!lparen && lop != op) { 1422 if (lop == PLUS || lop == MINUS) 1423 return true; 1424 if (lop == BITAND || lop == BITXOR) 1425 return true; 1426 } 1427 if (!rparen && rop != op) { 1428 if (rop == PLUS || rop == MINUS) 1429 return true; 1430 if (rop == BITAND || rop == BITXOR) 1431 return true; 1432 } 1433 return false; 1434 } 1435 1436 /* 1437 * Print a warning if the given node has operands which should be 1438 * parenthesized. 1439 * 1440 * XXX Does not work if an operand is a constant expression. Constant 1441 * expressions are already folded. 1442 */ 1443 static void 1444 check_precedence_confusion(tnode_t *tn) 1445 { 1446 tnode_t *ln, *rn; 1447 1448 if (!hflag) 1449 return; 1450 1451 debug_node(tn); 1452 1453 lint_assert(is_binary(tn)); 1454 for (ln = tn->tn_left; ln->tn_op == CVT; ln = ln->tn_left) 1455 continue; 1456 for (rn = tn->tn_right; rn->tn_op == CVT; rn = rn->tn_left) 1457 continue; 1458 1459 if (is_confusing_precedence(tn->tn_op, 1460 ln->tn_op, ln->tn_parenthesized, 1461 rn->tn_op, rn->tn_parenthesized)) { 1462 /* precedence confusion possible: parenthesize! */ 1463 warning(169); 1464 } 1465 } 1466 1467 /* 1468 * Fold constant nodes, as much as is needed for comparing the value with 0. 1469 */ 1470 static tnode_t * 1471 fold_bool(tnode_t *tn) 1472 { 1473 bool l, r; 1474 val_t *v; 1475 1476 v = xcalloc(1, sizeof(*v)); 1477 v->v_tspec = tn->tn_type->t_tspec; 1478 lint_assert(v->v_tspec == INT || (Tflag && v->v_tspec == BOOL)); 1479 1480 l = constant_is_nonzero(tn->tn_left); 1481 r = is_binary(tn) && constant_is_nonzero(tn->tn_right); 1482 1483 switch (tn->tn_op) { 1484 case NOT: 1485 if (hflag && !constcond_flag) 1486 /* constant argument to '!' */ 1487 warning(239); 1488 v->v_quad = !l ? 1 : 0; 1489 break; 1490 case LOGAND: 1491 v->v_quad = l && r ? 1 : 0; 1492 break; 1493 case LOGOR: 1494 v->v_quad = l || r ? 1 : 0; 1495 break; 1496 default: 1497 lint_assert(/*CONSTCOND*/false); 1498 } 1499 1500 return build_constant(tn->tn_type, v); 1501 } 1502 1503 static ldbl_t 1504 floating_error_value(tspec_t t, ldbl_t lv) 1505 { 1506 if (t == FLOAT) 1507 return lv < 0 ? -FLT_MAX : FLT_MAX; 1508 if (t == DOUBLE) 1509 return lv < 0 ? -DBL_MAX : DBL_MAX; 1510 return lv < 0 ? -LDBL_MAX : LDBL_MAX; 1511 } 1512 1513 /* 1514 * Fold constant nodes having operands with floating point type. 1515 */ 1516 static tnode_t * 1517 fold_float(tnode_t *tn) 1518 { 1519 val_t *v; 1520 tspec_t t; 1521 ldbl_t lv, rv = 0; 1522 1523 fpe = 0; 1524 v = xcalloc(1, sizeof(*v)); 1525 v->v_tspec = t = tn->tn_type->t_tspec; 1526 1527 lint_assert(is_floating(t)); 1528 lint_assert(t == tn->tn_left->tn_type->t_tspec); 1529 lint_assert(!is_binary(tn) || t == tn->tn_right->tn_type->t_tspec); 1530 1531 lv = tn->tn_left->tn_val->v_ldbl; 1532 if (is_binary(tn)) 1533 rv = tn->tn_right->tn_val->v_ldbl; 1534 1535 switch (tn->tn_op) { 1536 case UPLUS: 1537 v->v_ldbl = lv; 1538 break; 1539 case UMINUS: 1540 v->v_ldbl = -lv; 1541 break; 1542 case MULT: 1543 v->v_ldbl = lv * rv; 1544 break; 1545 case DIV: 1546 if (rv == 0.0) { 1547 /* division by 0 */ 1548 error(139); 1549 v->v_ldbl = floating_error_value(t, lv); 1550 } else { 1551 v->v_ldbl = lv / rv; 1552 } 1553 break; 1554 case PLUS: 1555 v->v_ldbl = lv + rv; 1556 break; 1557 case MINUS: 1558 v->v_ldbl = lv - rv; 1559 break; 1560 case LT: 1561 v->v_quad = lv < rv ? 1 : 0; 1562 break; 1563 case LE: 1564 v->v_quad = lv <= rv ? 1 : 0; 1565 break; 1566 case GE: 1567 v->v_quad = lv >= rv ? 1 : 0; 1568 break; 1569 case GT: 1570 v->v_quad = lv > rv ? 1 : 0; 1571 break; 1572 case EQ: 1573 v->v_quad = lv == rv ? 1 : 0; 1574 break; 1575 case NE: 1576 v->v_quad = lv != rv ? 1 : 0; 1577 break; 1578 default: 1579 lint_assert(/*CONSTCOND*/false); 1580 } 1581 1582 lint_assert(fpe != 0 || isnan(v->v_ldbl) == 0); 1583 if (is_complex(v->v_tspec)) { 1584 /* 1585 * Don't warn, as lint doesn't model the imaginary part of 1586 * complex numbers. 1587 */ 1588 fpe = 0; 1589 } else if (fpe != 0 || isfinite(v->v_ldbl) == 0 || 1590 (t == FLOAT && 1591 (v->v_ldbl > FLT_MAX || v->v_ldbl < -FLT_MAX)) || 1592 (t == DOUBLE && 1593 (v->v_ldbl > DBL_MAX || v->v_ldbl < -DBL_MAX))) { 1594 /* floating point overflow on operator '%s' */ 1595 warning(142, op_name(tn->tn_op)); 1596 v->v_ldbl = floating_error_value(t, v->v_ldbl); 1597 fpe = 0; 1598 } 1599 1600 return build_constant(tn->tn_type, v); 1601 } 1602 1603 /* 1604 * Create a tree node for a binary operator and its two operands. Also called 1605 * for unary operators; in that case rn is NULL. 1606 * 1607 * Function calls, sizeof and casts are handled elsewhere. 1608 */ 1609 tnode_t * 1610 build_binary(tnode_t *ln, op_t op, bool sys, tnode_t *rn) 1611 { 1612 const mod_t *mp; 1613 tnode_t *ntn; 1614 type_t *rettp; 1615 1616 mp = &modtab[op]; 1617 1618 /* If there was an error in one of the operands, return. */ 1619 if (ln == NULL || (mp->m_binary && rn == NULL)) 1620 return NULL; 1621 1622 /* 1623 * Apply class conversions to the left operand, but only if its 1624 * value is needed or it is compared with zero. 1625 */ 1626 if (mp->m_value_context || mp->m_compares_with_zero) 1627 ln = cconv(ln); 1628 /* 1629 * The right operand is almost always in a test or value context, 1630 * except if it is a struct or union member. 1631 */ 1632 if (mp->m_binary && op != ARROW && op != POINT) 1633 rn = cconv(rn); 1634 1635 /* 1636 * Print some warnings for comparisons of unsigned values with 1637 * constants lower than or equal to null. This must be done 1638 * before promote() because otherwise unsigned char and unsigned 1639 * short would be promoted to int. Types are also tested to be 1640 * CHAR, which would also become int. 1641 */ 1642 if (mp->m_comparison) 1643 check_integer_comparison(op, ln, rn); 1644 1645 if (mp->m_value_context || mp->m_compares_with_zero) 1646 ln = promote(op, false, ln); 1647 if (mp->m_binary && op != ARROW && op != POINT && 1648 op != ASSIGN && op != RETURN && op != INIT) { 1649 rn = promote(op, false, rn); 1650 } 1651 1652 /* 1653 * If the result of the operation is different for signed or 1654 * unsigned operands and one of the operands is signed only in 1655 * ANSI C, print a warning. 1656 */ 1657 if (mp->m_warn_if_left_unsigned_in_c90 && 1658 ln->tn_op == CON && ln->tn_val->v_unsigned_since_c90) { 1659 /* ANSI C treats constant as unsigned, op '%s' */ 1660 warning(218, mp->m_name); 1661 ln->tn_val->v_unsigned_since_c90 = false; 1662 } 1663 if (mp->m_warn_if_right_unsigned_in_c90 && 1664 rn->tn_op == CON && rn->tn_val->v_unsigned_since_c90) { 1665 /* ANSI C treats constant as unsigned, op '%s' */ 1666 warning(218, mp->m_name); 1667 rn->tn_val->v_unsigned_since_c90 = false; 1668 } 1669 1670 /* Make sure both operands are of the same type */ 1671 if (mp->m_balance_operands || (!allow_c90 && (op == SHL || op == SHR))) 1672 balance(op, &ln, &rn); 1673 1674 /* 1675 * Check types for compatibility with the operation and mutual 1676 * compatibility. Return if there are serious problems. 1677 */ 1678 if (!typeok(op, 0, ln, rn)) 1679 return NULL; 1680 1681 /* And now create the node. */ 1682 switch (op) { 1683 case POINT: 1684 case ARROW: 1685 ntn = build_struct_access(op, sys, ln, rn); 1686 break; 1687 case INCAFT: 1688 case DECAFT: 1689 case INCBEF: 1690 case DECBEF: 1691 ntn = build_prepost_incdec(op, sys, ln); 1692 break; 1693 case ADDR: 1694 ntn = build_address(sys, ln, false); 1695 break; 1696 case INDIR: 1697 ntn = new_tnode(INDIR, sys, ln->tn_type->t_subt, ln, NULL); 1698 break; 1699 case PLUS: 1700 case MINUS: 1701 ntn = build_plus_minus(op, sys, ln, rn); 1702 break; 1703 case SHL: 1704 case SHR: 1705 ntn = build_bit_shift(op, sys, ln, rn); 1706 break; 1707 case COLON: 1708 ntn = build_colon(sys, ln, rn); 1709 break; 1710 case ASSIGN: 1711 case MULASS: 1712 case DIVASS: 1713 case MODASS: 1714 case ADDASS: 1715 case SUBASS: 1716 case SHLASS: 1717 case SHRASS: 1718 case ANDASS: 1719 case XORASS: 1720 case ORASS: 1721 case RETURN: 1722 case INIT: 1723 ntn = build_assignment(op, sys, ln, rn); 1724 break; 1725 case COMMA: 1726 case QUEST: 1727 ntn = new_tnode(op, sys, rn->tn_type, ln, rn); 1728 break; 1729 case REAL: 1730 case IMAG: 1731 ntn = build_real_imag(op, sys, ln); 1732 break; 1733 default: 1734 rettp = mp->m_returns_bool 1735 ? gettyp(Tflag ? BOOL : INT) : ln->tn_type; 1736 lint_assert(mp->m_binary == (rn != NULL)); 1737 ntn = new_tnode(op, sys, rettp, ln, rn); 1738 break; 1739 } 1740 1741 /* Return if an error occurred. */ 1742 if (ntn == NULL) 1743 return NULL; 1744 1745 /* Print a warning if precedence confusion is possible */ 1746 if (mp->m_possible_precedence_confusion) 1747 check_precedence_confusion(ntn); 1748 1749 /* 1750 * Print a warning if one of the operands is in a context where 1751 * it is compared with zero and if this operand is a constant. 1752 */ 1753 if (hflag && !constcond_flag && 1754 mp->m_compares_with_zero && 1755 (ln->tn_op == CON || 1756 ((mp->m_binary && op != QUEST) && rn->tn_op == CON)) && 1757 /* XXX: rn->tn_system_dependent should be checked as well */ 1758 !ln->tn_system_dependent) { 1759 /* constant in conditional context */ 1760 warning(161); 1761 } 1762 1763 /* Fold if the operator requires it */ 1764 if (mp->m_fold_constant_operands) { 1765 if (ln->tn_op == CON && (!mp->m_binary || rn->tn_op == CON)) { 1766 if (mp->m_compares_with_zero) { 1767 ntn = fold_bool(ntn); 1768 } else if (is_floating(ntn->tn_type->t_tspec)) { 1769 ntn = fold_float(ntn); 1770 } else { 1771 ntn = fold(ntn); 1772 } 1773 } else if (op == QUEST && ln->tn_op == CON) { 1774 ntn = ln->tn_val->v_quad != 0 1775 ? rn->tn_left : rn->tn_right; 1776 } 1777 } 1778 1779 return ntn; 1780 } 1781 1782 tnode_t * 1783 build_unary(op_t op, bool sys, tnode_t *tn) 1784 { 1785 return build_binary(tn, op, sys, NULL); 1786 } 1787 1788 /* 1789 * Return whether all struct/union members with the same name have the same 1790 * type and offset. 1791 */ 1792 static bool 1793 all_members_compatible(const sym_t *msym) 1794 { 1795 for (const sym_t *csym = msym; 1796 csym != NULL; csym = csym->s_symtab_next) { 1797 if (!is_member(csym)) 1798 continue; 1799 if (strcmp(msym->s_name, csym->s_name) != 0) 1800 continue; 1801 1802 for (const sym_t *sym = csym->s_symtab_next; 1803 sym != NULL; sym = sym->s_symtab_next) { 1804 1805 if (!is_member(sym)) 1806 continue; 1807 if (strcmp(csym->s_name, sym->s_name) != 0) 1808 continue; 1809 if (csym->u.s_member.sm_offset_in_bits != 1810 sym->u.s_member.sm_offset_in_bits) 1811 return false; 1812 1813 bool w = false; 1814 if (!types_compatible(csym->s_type, sym->s_type, 1815 false, false, &w) && !w) 1816 return false; 1817 if (csym->s_bitfield != sym->s_bitfield) 1818 return false; 1819 if (csym->s_bitfield) { 1820 type_t *tp1 = csym->s_type; 1821 type_t *tp2 = sym->s_type; 1822 if (tp1->t_flen != tp2->t_flen) 1823 return false; 1824 if (tp1->t_foffs != tp2->t_foffs) 1825 return false; 1826 } 1827 } 1828 } 1829 return true; 1830 } 1831 1832 /* 1833 * Returns a symbol which has the same name as the msym argument and is a 1834 * member of the struct or union specified by the tn argument. 1835 */ 1836 static sym_t * 1837 struct_or_union_member(tnode_t *tn, op_t op, sym_t *msym) 1838 { 1839 struct_or_union *str; 1840 type_t *tp; 1841 tspec_t t; 1842 1843 /* 1844 * Remove the member if it was unknown until now, which means 1845 * that no defined struct or union has a member with the same name. 1846 */ 1847 if (msym->s_scl == NOSCL) { 1848 /* type '%s' does not have member '%s' */ 1849 error(101, type_name(tn->tn_type), msym->s_name); 1850 rmsym(msym); 1851 msym->s_kind = FMEMBER; 1852 msym->s_scl = STRUCT_MEMBER; 1853 1854 struct_or_union *sou = expr_zero_alloc(sizeof(*sou)); 1855 sou->sou_tag = expr_zero_alloc(sizeof(*sou->sou_tag)); 1856 sou->sou_tag->s_name = unnamed; 1857 1858 msym->u.s_member.sm_sou_type = sou; 1859 /* 1860 * The member sm_offset_in_bits is not needed here since this 1861 * symbol can only be used for error reporting. 1862 */ 1863 return msym; 1864 } 1865 1866 /* Set str to the tag of which msym is expected to be a member. */ 1867 str = NULL; 1868 t = (tp = tn->tn_type)->t_tspec; 1869 if (op == POINT) { 1870 if (is_struct_or_union(t)) 1871 str = tp->t_str; 1872 } else if (op == ARROW && t == PTR) { 1873 t = (tp = tp->t_subt)->t_tspec; 1874 if (is_struct_or_union(t)) 1875 str = tp->t_str; 1876 } 1877 1878 /* 1879 * If this struct/union has a member with the name of msym, return it. 1880 */ 1881 if (str != NULL) { 1882 for (sym_t *sym = msym; 1883 sym != NULL; sym = sym->s_symtab_next) { 1884 if (is_member(sym) && 1885 sym->u.s_member.sm_sou_type == str && 1886 strcmp(sym->s_name, msym->s_name) == 0) 1887 return sym; 1888 } 1889 } 1890 1891 bool eq = all_members_compatible(msym); 1892 1893 /* 1894 * Now handle the case in which the left operand refers really 1895 * to a struct/union, but the right operand is not member of it. 1896 */ 1897 if (str != NULL) { 1898 if (eq && !allow_c90) { 1899 /* illegal use of member '%s' */ 1900 warning(102, msym->s_name); 1901 } else { 1902 /* illegal use of member '%s' */ 1903 error(102, msym->s_name); 1904 } 1905 return msym; 1906 } 1907 1908 /* 1909 * Now the left operand of ARROW does not point to a struct/union 1910 * or the left operand of POINT is no struct/union. 1911 */ 1912 if (eq) { 1913 if (op == POINT) { 1914 if (!allow_c90) { 1915 /* left operand of '.' must be struct ... */ 1916 warning(103, type_name(tn->tn_type)); 1917 } else { 1918 /* left operand of '.' must be struct ... */ 1919 error(103, type_name(tn->tn_type)); 1920 } 1921 } else { 1922 if (!allow_c90 && tn->tn_type->t_tspec == PTR) { 1923 /* left operand of '->' must be pointer ... */ 1924 warning(104, type_name(tn->tn_type)); 1925 } else { 1926 /* left operand of '->' must be pointer ... */ 1927 error(104, type_name(tn->tn_type)); 1928 } 1929 } 1930 } else { 1931 if (!allow_c90) { 1932 /* non-unique member requires struct/union %s */ 1933 error(105, op == POINT ? "object" : "pointer"); 1934 } else { 1935 /* unacceptable operand of '%s' */ 1936 error(111, op_name(op)); 1937 } 1938 } 1939 1940 return msym; 1941 } 1942 1943 tnode_t * 1944 build_member_access(tnode_t *ln, op_t op, bool sys, sbuf_t *member) 1945 { 1946 sym_t *msym; 1947 1948 if (ln == NULL) 1949 return NULL; 1950 1951 if (op == ARROW) { 1952 /* must do this before struct_or_union_member is called */ 1953 ln = cconv(ln); 1954 } 1955 msym = struct_or_union_member(ln, op, getsym(member)); 1956 return build_binary(ln, op, sys, build_name(msym, false)); 1957 } 1958 1959 /* 1960 * Perform class conversions. 1961 * 1962 * Arrays of type T are converted into pointers to type T. 1963 * Functions are converted to pointers to functions. 1964 * Lvalues are converted to rvalues. 1965 * 1966 * C99 6.3 "Conversions" 1967 * C99 6.3.2 "Other operands" 1968 * C99 6.3.2.1 "Lvalues, arrays, and function designators" 1969 */ 1970 tnode_t * 1971 cconv(tnode_t *tn) 1972 { 1973 /* 1974 * Array-lvalue (array of type T) is converted into rvalue 1975 * (pointer to type T) 1976 */ 1977 if (tn->tn_type->t_tspec == ARRAY) { 1978 if (!tn->tn_lvalue) { 1979 /* XXX print correct operator */ 1980 /* %soperand of '%s' must be lvalue */ 1981 gnuism(114, "", op_name(ADDR)); 1982 } 1983 tn = new_tnode(ADDR, tn->tn_sys, 1984 expr_derive_type(tn->tn_type->t_subt, PTR), tn, NULL); 1985 } 1986 1987 /* 1988 * Expression of type function (function with return value of type T) 1989 * in rvalue-expression (pointer to function with return value 1990 * of type T) 1991 */ 1992 if (tn->tn_type->t_tspec == FUNC) 1993 tn = build_address(tn->tn_sys, tn, true); 1994 1995 /* lvalue to rvalue */ 1996 if (tn->tn_lvalue) { 1997 type_t *tp = expr_dup_type(tn->tn_type); 1998 /* C99 6.3.2.1p2 sentence 2 says to remove the qualifiers. */ 1999 tp->t_const = tp->t_volatile = false; 2000 tn = new_tnode(LOAD, tn->tn_sys, tp, tn, NULL); 2001 } 2002 2003 return tn; 2004 } 2005 2006 const tnode_t * 2007 before_conversion(const tnode_t *tn) 2008 { 2009 while (tn->tn_op == CVT && !tn->tn_cast) 2010 tn = tn->tn_left; 2011 return tn; 2012 } 2013 2014 /* 2015 * Most errors required by ANSI C are reported in struct_or_union_member(). 2016 * Here we only check for totally wrong things. 2017 */ 2018 static bool 2019 typeok_point(const tnode_t *ln, const type_t *ltp, tspec_t lt) 2020 { 2021 if (is_struct_or_union(lt)) 2022 return true; 2023 2024 if (lt == FUNC || lt == VOID || ltp->t_bitfield) 2025 goto wrong; 2026 2027 /* 2028 * Some C dialects from before C90 tolerated any lvalue on the 2029 * left-hand side of the '.' operator, allowing things like 2030 * char st[100]; st.st_mtime, assuming that the member 'st_mtime' 2031 * only occurred in a single struct; see typeok_arrow. 2032 */ 2033 if (ln->tn_lvalue) 2034 return true; 2035 2036 wrong: 2037 /* With allow_c90 we already got an error */ 2038 if (!allow_c90) 2039 /* unacceptable operand of '%s' */ 2040 error(111, op_name(POINT)); 2041 2042 return false; 2043 } 2044 2045 static bool 2046 typeok_arrow(tspec_t lt) 2047 { 2048 /* 2049 * C1978 Appendix A 14.1 says: <quote>In fact, any lvalue is allowed 2050 * before '.', and that lvalue is then assumed to have the form of 2051 * the structure of which the name of the right is a member. [...] 2052 * Such constructions are non-portable.</quote> 2053 */ 2054 if (lt == PTR || (!allow_c90 && is_integer(lt))) 2055 return true; 2056 2057 /* With allow_c90 we already got an error */ 2058 if (!allow_c90) 2059 /* unacceptable operand of '%s' */ 2060 error(111, op_name(ARROW)); 2061 return false; 2062 } 2063 2064 static bool 2065 typeok_incdec(op_t op, const tnode_t *tn, const type_t *tp) 2066 { 2067 /* operand has scalar type (checked in typeok) */ 2068 if (!tn->tn_lvalue) { 2069 if (tn->tn_op == CVT && tn->tn_cast && 2070 tn->tn_left->tn_op == LOAD) { 2071 /* a cast does not yield an lvalue */ 2072 error(163); 2073 } 2074 /* %soperand of '%s' must be lvalue */ 2075 error(114, "", op_name(op)); 2076 return false; 2077 } 2078 if (tp->t_const && allow_c90) { 2079 /* %soperand of '%s' must be modifiable lvalue */ 2080 warning(115, "", op_name(op)); 2081 } 2082 return true; 2083 } 2084 2085 static bool 2086 typeok_address(const mod_t *mp, 2087 const tnode_t *tn, const type_t *tp, tspec_t t) 2088 { 2089 if (t == ARRAY || t == FUNC) { 2090 /* ok, a warning comes later (in build_address()) */ 2091 } else if (!tn->tn_lvalue) { 2092 if (tn->tn_op == CVT && tn->tn_cast && 2093 tn->tn_left->tn_op == LOAD) { 2094 /* a cast does not yield an lvalue */ 2095 error(163); 2096 } 2097 /* %soperand of '%s' must be lvalue */ 2098 error(114, "", mp->m_name); 2099 return false; 2100 } else if (is_scalar(t)) { 2101 if (tp->t_bitfield) { 2102 /* cannot take address of bit-field */ 2103 error(112); 2104 return false; 2105 } 2106 } else if (t != STRUCT && t != UNION) { 2107 /* unacceptable operand of '%s' */ 2108 error(111, mp->m_name); 2109 return false; 2110 } 2111 if (tn->tn_op == NAME && tn->tn_sym->s_register) { 2112 /* cannot take address of register '%s' */ 2113 error(113, tn->tn_sym->s_name); 2114 return false; 2115 } 2116 return true; 2117 } 2118 2119 static bool 2120 typeok_indir(const type_t *tp, tspec_t t) 2121 { 2122 2123 if (t != PTR) { 2124 /* cannot dereference non-pointer type '%s' */ 2125 error(96, type_name(tp)); 2126 return false; 2127 } 2128 return true; 2129 } 2130 2131 static void 2132 warn_incompatible_types(op_t op, 2133 const type_t *ltp, tspec_t lt, 2134 const type_t *rtp, tspec_t rt) 2135 { 2136 const mod_t *mp = &modtab[op]; 2137 2138 if (lt == VOID || (mp->m_binary && rt == VOID)) { 2139 /* void type illegal in expression */ 2140 error(109); 2141 } else if (op == ASSIGN) { 2142 /* cannot assign to '%s' from '%s' */ 2143 error(171, type_name(ltp), type_name(rtp)); 2144 } else if (mp->m_binary) { 2145 /* operands of '%s' have incompatible types '%s' and '%s' */ 2146 error(107, mp->m_name, tspec_name(lt), tspec_name(rt)); 2147 } else { 2148 lint_assert(rt == NOTSPEC); 2149 /* operand of '%s' has invalid type '%s' */ 2150 error(108, mp->m_name, type_name(ltp)); 2151 } 2152 } 2153 2154 static bool 2155 typeok_plus(op_t op, 2156 const type_t *ltp, tspec_t lt, 2157 const type_t *rtp, tspec_t rt) 2158 { 2159 /* operands have scalar types (checked in typeok) */ 2160 if ((lt == PTR && !is_integer(rt)) || (rt == PTR && !is_integer(lt))) { 2161 warn_incompatible_types(op, ltp, lt, rtp, rt); 2162 return false; 2163 } 2164 return true; 2165 } 2166 2167 static bool 2168 typeok_minus(op_t op, 2169 const type_t *ltp, tspec_t lt, 2170 const type_t *rtp, tspec_t rt) 2171 { 2172 /* operands have scalar types (checked in typeok) */ 2173 if ((lt == PTR && rt != PTR && !is_integer(rt)) || 2174 (lt != PTR && rt == PTR)) { 2175 warn_incompatible_types(op, ltp, lt, rtp, rt); 2176 return false; 2177 } 2178 if (lt == PTR && rt == PTR && 2179 !types_compatible(ltp->t_subt, rtp->t_subt, true, false, NULL)) { 2180 /* illegal pointer subtraction */ 2181 error(116); 2182 } 2183 return true; 2184 } 2185 2186 static void 2187 typeok_shr(const mod_t *mp, 2188 const tnode_t *ln, tspec_t lt, 2189 const tnode_t *rn, tspec_t rt) 2190 { 2191 tspec_t olt, ort; 2192 2193 olt = before_conversion(ln)->tn_type->t_tspec; 2194 ort = before_conversion(rn)->tn_type->t_tspec; 2195 2196 /* operands have integer types (checked in typeok) */ 2197 if (pflag && !is_uinteger(olt)) { 2198 integer_constraints lc = ic_expr(ln); 2199 if (!ic_maybe_signed(ln->tn_type, &lc)) 2200 return; 2201 2202 /* 2203 * The left operand is signed. This means that 2204 * the operation is (possibly) nonportable. 2205 */ 2206 if (ln->tn_op != CON) { 2207 /* bitwise '%s' on signed value possibly nonportable */ 2208 warning(117, mp->m_name); 2209 } else if (ln->tn_val->v_quad < 0) { 2210 /* bitwise '%s' on signed value nonportable */ 2211 warning(120, mp->m_name); 2212 } 2213 } else if (allow_trad && allow_c90 && 2214 !is_uinteger(olt) && is_uinteger(ort)) { 2215 /* The left operand would become unsigned in traditional C. */ 2216 if (hflag && (ln->tn_op != CON || ln->tn_val->v_quad < 0)) { 2217 /* semantics of '%s' change in ANSI C; use ... */ 2218 warning(118, mp->m_name); 2219 } 2220 } else if (allow_trad && allow_c90 && 2221 !is_uinteger(olt) && !is_uinteger(ort) && 2222 portable_size_in_bits(lt) < portable_size_in_bits(rt)) { 2223 /* 2224 * In traditional C the left operand would be extended 2225 * (possibly sign-extended) and then shifted. 2226 */ 2227 if (hflag && (ln->tn_op != CON || ln->tn_val->v_quad < 0)) { 2228 /* semantics of '%s' change in ANSI C; use ... */ 2229 warning(118, mp->m_name); 2230 } 2231 } 2232 } 2233 2234 static void 2235 typeok_shl(const mod_t *mp, tspec_t lt, tspec_t rt) 2236 { 2237 /* 2238 * C90 does not perform balancing for shift operations, 2239 * but traditional C does. If the width of the right operand 2240 * is greater than the width of the left operand, then in 2241 * traditional C the left operand would be extended to the 2242 * width of the right operand. For SHL this may result in 2243 * different results. 2244 */ 2245 if (portable_size_in_bits(lt) < portable_size_in_bits(rt)) { 2246 /* 2247 * XXX If both operands are constant, make sure 2248 * that there is really a difference between 2249 * ANSI C and traditional C. 2250 */ 2251 if (hflag && !allow_c99) 2252 /* semantics of '%s' change in ANSI C; use ... */ 2253 warning(118, mp->m_name); 2254 } 2255 } 2256 2257 static void 2258 typeok_shift(const type_t *ltp, tspec_t lt, const tnode_t *rn, tspec_t rt) 2259 { 2260 if (rn->tn_op != CON) 2261 return; 2262 2263 if (!is_uinteger(rt) && rn->tn_val->v_quad < 0) { 2264 /* negative shift */ 2265 warning(121); 2266 } else if ((uint64_t)rn->tn_val->v_quad == 2267 (uint64_t)size_in_bits(lt)) { 2268 /* shift amount %u equals bit-size of '%s' */ 2269 warning(267, (unsigned)rn->tn_val->v_quad, type_name(ltp)); 2270 } else if ((uint64_t)rn->tn_val->v_quad > (uint64_t)size_in_bits(lt)) { 2271 /* shift amount %llu is greater than bit-size %llu of '%s' */ 2272 warning(122, (unsigned long long)rn->tn_val->v_quad, 2273 (unsigned long long)size_in_bits(lt), 2274 tspec_name(lt)); 2275 } 2276 } 2277 2278 static bool 2279 is_typeok_eq(const tnode_t *ln, tspec_t lt, const tnode_t *rn, tspec_t rt) 2280 { 2281 if (lt == PTR && is_null_pointer(rn)) 2282 return true; 2283 if (rt == PTR && is_null_pointer(ln)) 2284 return true; 2285 return false; 2286 } 2287 2288 /* 2289 * Called if incompatible pointer types are detected. 2290 * Print an appropriate warning. 2291 */ 2292 static void 2293 warn_incompatible_pointers(const mod_t *mp, 2294 const type_t *ltp, const type_t *rtp) 2295 { 2296 lint_assert(ltp->t_tspec == PTR); 2297 lint_assert(rtp->t_tspec == PTR); 2298 2299 tspec_t lt = ltp->t_subt->t_tspec; 2300 tspec_t rt = rtp->t_subt->t_tspec; 2301 2302 if (is_struct_or_union(lt) && is_struct_or_union(rt)) { 2303 if (mp == NULL) { 2304 /* illegal structure pointer combination */ 2305 warning(244); 2306 } else { 2307 /* incompatible structure pointers: '%s' '%s' '%s' */ 2308 warning(245, type_name(ltp), mp->m_name, type_name(rtp)); 2309 } 2310 } else { 2311 if (mp == NULL) { 2312 /* illegal combination of '%s' and '%s' */ 2313 warning(184, type_name(ltp), type_name(rtp)); 2314 } else { 2315 /* illegal combination of '%s' and '%s', op '%s' */ 2316 warning(124, 2317 type_name(ltp), type_name(rtp), mp->m_name); 2318 } 2319 } 2320 } 2321 2322 static void 2323 check_pointer_comparison(op_t op, const tnode_t *ln, const tnode_t *rn) 2324 { 2325 type_t *ltp = ln->tn_type, *rtp = rn->tn_type; 2326 tspec_t lst = ltp->t_subt->t_tspec, rst = rtp->t_subt->t_tspec; 2327 2328 if (lst == VOID || rst == VOID) { 2329 /* TODO: C99 behaves like C90 here. */ 2330 if ((!allow_trad && !allow_c99) && 2331 (lst == FUNC || rst == FUNC)) { 2332 /* (void *)0 is already handled in typeok() */ 2333 const char *lsts, *rsts; 2334 *(lst == FUNC ? &lsts : &rsts) = "function pointer"; 2335 *(lst == VOID ? &lsts : &rsts) = "'void *'"; 2336 /* ANSI C forbids comparison of %s with %s */ 2337 warning(274, lsts, rsts); 2338 } 2339 return; 2340 } 2341 2342 if (!types_compatible(ltp->t_subt, rtp->t_subt, true, false, NULL)) { 2343 warn_incompatible_pointers(&modtab[op], ltp, rtp); 2344 return; 2345 } 2346 2347 if (lst == FUNC && rst == FUNC) { 2348 /* TODO: C99 behaves like C90 here, see C99 6.5.8p2. */ 2349 if ((!allow_trad && !allow_c99) && op != EQ && op != NE) 2350 /* ANSI C forbids ordered comparisons of ... */ 2351 warning(125); 2352 } 2353 } 2354 2355 static bool 2356 typeok_compare(op_t op, 2357 const tnode_t *ln, const type_t *ltp, tspec_t lt, 2358 const tnode_t *rn, const type_t *rtp, tspec_t rt) 2359 { 2360 if (lt == PTR && rt == PTR) { 2361 check_pointer_comparison(op, ln, rn); 2362 return true; 2363 } 2364 2365 if (lt != PTR && rt != PTR) 2366 return true; 2367 2368 if (!is_integer(lt) && !is_integer(rt)) { 2369 warn_incompatible_types(op, ltp, lt, rtp, rt); 2370 return false; 2371 } 2372 2373 const char *lx = lt == PTR ? "pointer" : "integer"; 2374 const char *rx = rt == PTR ? "pointer" : "integer"; 2375 /* illegal combination of %s '%s' and %s '%s', op '%s' */ 2376 warning(123, lx, type_name(ltp), rx, type_name(rtp), op_name(op)); 2377 return true; 2378 } 2379 2380 static bool 2381 typeok_quest(tspec_t lt, const tnode_t *rn) 2382 { 2383 if (!is_scalar(lt)) { 2384 /* first operand must have scalar type, op ? : */ 2385 error(170); 2386 return false; 2387 } 2388 lint_assert(before_conversion(rn)->tn_op == COLON); 2389 return true; 2390 } 2391 2392 static void 2393 typeok_colon_pointer(const mod_t *mp, const type_t *ltp, const type_t *rtp) 2394 { 2395 type_t *lstp = ltp->t_subt; 2396 type_t *rstp = rtp->t_subt; 2397 tspec_t lst = lstp->t_tspec; 2398 tspec_t rst = rstp->t_tspec; 2399 2400 if ((lst == VOID && rst == FUNC) || (lst == FUNC && rst == VOID)) { 2401 /* (void *)0 is handled in typeok_colon */ 2402 /* TODO: C99 behaves like C90 here. */ 2403 if (!allow_trad && !allow_c99) 2404 /* ANSI C forbids conversion of %s to %s, op %s */ 2405 warning(305, "function pointer", "'void *'", 2406 mp->m_name); 2407 return; 2408 } 2409 2410 if (pointer_types_are_compatible(lstp, rstp, true)) 2411 return; 2412 if (!types_compatible(lstp, rstp, true, false, NULL)) 2413 warn_incompatible_pointers(mp, ltp, rtp); 2414 } 2415 2416 static bool 2417 typeok_colon(const mod_t *mp, 2418 const tnode_t *ln, const type_t *ltp, tspec_t lt, 2419 const tnode_t *rn, const type_t *rtp, tspec_t rt) 2420 { 2421 2422 if (is_arithmetic(lt) && is_arithmetic(rt)) 2423 return true; 2424 if (lt == BOOL && rt == BOOL) 2425 return true; 2426 2427 if (lt == STRUCT && rt == STRUCT && ltp->t_str == rtp->t_str) 2428 return true; 2429 if (lt == UNION && rt == UNION && ltp->t_str == rtp->t_str) 2430 return true; 2431 2432 if (lt == PTR && is_null_pointer(rn)) 2433 return true; 2434 if (rt == PTR && is_null_pointer(ln)) 2435 return true; 2436 2437 if ((lt == PTR && is_integer(rt)) || (is_integer(lt) && rt == PTR)) { 2438 const char *lx = lt == PTR ? "pointer" : "integer"; 2439 const char *rx = rt == PTR ? "pointer" : "integer"; 2440 /* illegal combination of %s '%s' and %s '%s', op '%s' */ 2441 warning(123, lx, type_name(ltp), 2442 rx, type_name(rtp), mp->m_name); 2443 return true; 2444 } 2445 2446 if (lt == VOID || rt == VOID) { 2447 if (lt != VOID || rt != VOID) 2448 /* incompatible types '%s' and '%s' in conditional */ 2449 warning(126, type_name(ltp), type_name(rtp)); 2450 return true; 2451 } 2452 2453 if (lt == PTR && rt == PTR) { 2454 typeok_colon_pointer(mp, ltp, rtp); 2455 return true; 2456 } 2457 2458 /* incompatible types '%s' and '%s' in conditional */ 2459 error(126, type_name(ltp), type_name(rtp)); 2460 return false; 2461 } 2462 2463 /* 2464 * Returns true if the given structure or union has a constant member 2465 * (maybe recursively). 2466 */ 2467 static bool 2468 has_constant_member(const type_t *tp) 2469 { 2470 lint_assert(is_struct_or_union(tp->t_tspec)); 2471 2472 for (sym_t *m = tp->t_str->sou_first_member; 2473 m != NULL; m = m->s_next) { 2474 const type_t *mtp = m->s_type; 2475 if (mtp->t_const) 2476 return true; 2477 if (is_struct_or_union(mtp->t_tspec) && 2478 has_constant_member(mtp)) 2479 return true; 2480 } 2481 return false; 2482 } 2483 2484 static bool 2485 typeok_assign(op_t op, const tnode_t *ln, const type_t *ltp, tspec_t lt) 2486 { 2487 if (op == RETURN || op == INIT || op == FARG) 2488 return true; 2489 2490 if (!ln->tn_lvalue) { 2491 if (ln->tn_op == CVT && ln->tn_cast && 2492 ln->tn_left->tn_op == LOAD) { 2493 /* a cast does not yield an lvalue */ 2494 error(163); 2495 } 2496 /* %soperand of '%s' must be lvalue */ 2497 error(114, "left ", op_name(op)); 2498 return false; 2499 } else if (ltp->t_const || (is_struct_or_union(lt) && 2500 has_constant_member(ltp))) { 2501 if (allow_c90) 2502 /* %soperand of '%s' must be modifiable lvalue */ 2503 warning(115, "left ", op_name(op)); 2504 } 2505 return true; 2506 } 2507 2508 /* Check the types using the information from modtab[]. */ 2509 static bool 2510 typeok_scalar(op_t op, const mod_t *mp, 2511 const type_t *ltp, tspec_t lt, 2512 const type_t *rtp, tspec_t rt) 2513 { 2514 if (mp->m_takes_bool && lt == BOOL && rt == BOOL) 2515 return true; 2516 if (mp->m_requires_integer) { 2517 if (!is_integer(lt) || (mp->m_binary && !is_integer(rt))) { 2518 warn_incompatible_types(op, ltp, lt, rtp, rt); 2519 return false; 2520 } 2521 } else if (mp->m_requires_integer_or_complex) { 2522 if ((!is_integer(lt) && !is_complex(lt)) || 2523 (mp->m_binary && (!is_integer(rt) && !is_complex(rt)))) { 2524 warn_incompatible_types(op, ltp, lt, rtp, rt); 2525 return false; 2526 } 2527 } else if (mp->m_requires_scalar) { 2528 if (!is_scalar(lt) || (mp->m_binary && !is_scalar(rt))) { 2529 warn_incompatible_types(op, ltp, lt, rtp, rt); 2530 return false; 2531 } 2532 } else if (mp->m_requires_arith) { 2533 if (!is_arithmetic(lt) || 2534 (mp->m_binary && !is_arithmetic(rt))) { 2535 warn_incompatible_types(op, ltp, lt, rtp, rt); 2536 return false; 2537 } 2538 } 2539 return true; 2540 } 2541 2542 static void 2543 check_assign_void_pointer(op_t op, int arg, 2544 tspec_t lt, tspec_t lst, 2545 tspec_t rt, tspec_t rst) 2546 { 2547 2548 if (!(lt == PTR && rt == PTR && (lst == VOID || rst == VOID))) 2549 return; 2550 /* two pointers, at least one pointer to void */ 2551 2552 /* TODO: C99 behaves like C90 here. */ 2553 if (!((!allow_trad && !allow_c99) && (lst == FUNC || rst == FUNC))) 2554 return; 2555 /* comb. of ptr to func and ptr to void */ 2556 2557 const char *lts, *rts; 2558 *(lst == FUNC ? <s : &rts) = "function pointer"; 2559 *(lst == VOID ? <s : &rts) = "'void *'"; 2560 2561 switch (op) { 2562 case INIT: 2563 case RETURN: 2564 /* ANSI C forbids conversion of %s to %s */ 2565 warning(303, rts, lts); 2566 break; 2567 case FARG: 2568 /* ANSI C forbids conversion of %s to %s, arg #%d */ 2569 warning(304, rts, lts, arg); 2570 break; 2571 default: 2572 /* ANSI C forbids conversion of %s to %s, op %s */ 2573 warning(305, rts, lts, op_name(op)); 2574 break; 2575 } 2576 } 2577 2578 static bool 2579 is_direct_function_call(const tnode_t *tn, const char **out_name) 2580 { 2581 2582 if (!(tn->tn_op == CALL && 2583 tn->tn_left->tn_op == ADDR && 2584 tn->tn_left->tn_left->tn_op == NAME)) 2585 return false; 2586 2587 *out_name = tn->tn_left->tn_left->tn_sym->s_name; 2588 return true; 2589 } 2590 2591 static bool 2592 is_unconst_function(const char *name) 2593 { 2594 2595 return strcmp(name, "memchr") == 0 || 2596 strcmp(name, "strchr") == 0 || 2597 strcmp(name, "strpbrk") == 0 || 2598 strcmp(name, "strrchr") == 0 || 2599 strcmp(name, "strstr") == 0; 2600 } 2601 2602 static bool 2603 is_const_char_pointer(const tnode_t *tn) 2604 { 2605 /* 2606 * For traditional reasons, C99 6.4.5p5 defines that string literals 2607 * have type 'char[]'. They are often implicitly converted to 2608 * 'char *', for example when they are passed as function arguments. 2609 * 2610 * C99 6.4.5p6 further defines that modifying a string that is 2611 * constructed from a string literal invokes undefined behavior. 2612 * 2613 * Out of these reasons, string literals are treated as 'effectively 2614 * const' here. 2615 */ 2616 if (tn->tn_op == CVT && 2617 tn->tn_left->tn_op == ADDR && 2618 tn->tn_left->tn_left->tn_op == STRING) 2619 return true; 2620 2621 const type_t *tp = before_conversion(tn)->tn_type; 2622 return tp->t_tspec == PTR && 2623 tp->t_subt->t_tspec == CHAR && 2624 tp->t_subt->t_const; 2625 } 2626 2627 static bool 2628 is_first_arg_const_char_pointer(const tnode_t *tn) 2629 { 2630 const tnode_t *an = tn->tn_right; 2631 if (an == NULL) 2632 return false; 2633 2634 while (an->tn_right != NULL) 2635 an = an->tn_right; 2636 return is_const_char_pointer(an->tn_left); 2637 } 2638 2639 static bool 2640 is_const_pointer(const tnode_t *tn) 2641 { 2642 const type_t *tp = before_conversion(tn)->tn_type; 2643 return tp->t_tspec == PTR && tp->t_subt->t_const; 2644 } 2645 2646 static bool 2647 is_second_arg_const_pointer(const tnode_t *tn) 2648 { 2649 const tnode_t *an = tn->tn_right; 2650 if (an == NULL || an->tn_right == NULL) 2651 return false; 2652 2653 while (an->tn_right->tn_right != NULL) 2654 an = an->tn_right; 2655 return is_const_pointer(an->tn_left); 2656 } 2657 2658 static void 2659 check_unconst_function(const type_t *lstp, const tnode_t *rn) 2660 { 2661 const char *function_name; 2662 2663 if (lstp->t_tspec == CHAR && !lstp->t_const && 2664 is_direct_function_call(rn, &function_name) && 2665 is_unconst_function(function_name) && 2666 is_first_arg_const_char_pointer(rn)) { 2667 /* call to '%s' effectively discards 'const' from argument */ 2668 warning(346, function_name); 2669 } 2670 2671 if (!lstp->t_const && 2672 is_direct_function_call(rn, &function_name) && 2673 strcmp(function_name, "bsearch") == 0 && 2674 is_second_arg_const_pointer(rn)) { 2675 /* call to '%s' effectively discards 'const' from argument */ 2676 warning(346, function_name); 2677 } 2678 } 2679 2680 static bool 2681 check_assign_void_pointer_compat(op_t op, int arg, 2682 const type_t *const ltp, tspec_t const lt, 2683 const type_t *const lstp, tspec_t const lst, 2684 const tnode_t *const rn, 2685 const type_t *const rtp, tspec_t const rt, 2686 const type_t *const rstp, tspec_t const rst) 2687 { 2688 if (!(lt == PTR && rt == PTR && (lst == VOID || rst == VOID || 2689 types_compatible(lstp, rstp, 2690 true, false, NULL)))) 2691 return false; 2692 2693 /* compatible pointer types (qualifiers ignored) */ 2694 if (allow_c90 && 2695 ((!lstp->t_const && rstp->t_const) || 2696 (!lstp->t_volatile && rstp->t_volatile))) { 2697 /* left side has not all qualifiers of right */ 2698 switch (op) { 2699 case INIT: 2700 case RETURN: 2701 /* incompatible pointer types to '%s' and '%s' */ 2702 warning(182, type_name(lstp), type_name(rstp)); 2703 break; 2704 case FARG: 2705 /* converting '%s' to incompatible '%s' ... */ 2706 warning(153, 2707 type_name(rtp), type_name(ltp), arg); 2708 break; 2709 default: 2710 /* operands of '%s' have incompatible pointer ... */ 2711 warning(128, op_name(op), 2712 type_name(lstp), type_name(rstp)); 2713 break; 2714 } 2715 } 2716 2717 if (allow_c90) 2718 check_unconst_function(lstp, rn); 2719 2720 return true; 2721 } 2722 2723 static bool 2724 check_assign_pointer_integer(op_t op, int arg, 2725 const type_t *const ltp, tspec_t const lt, 2726 const type_t *const rtp, tspec_t const rt) 2727 { 2728 const char *lx, *rx; 2729 2730 if (!((lt == PTR && is_integer(rt)) || (is_integer(lt) && rt == PTR))) 2731 return false; 2732 2733 lx = lt == PTR ? "pointer" : "integer"; 2734 rx = rt == PTR ? "pointer" : "integer"; 2735 2736 switch (op) { 2737 case INIT: 2738 case RETURN: 2739 /* illegal combination of %s '%s' and %s '%s' */ 2740 warning(183, lx, type_name(ltp), rx, type_name(rtp)); 2741 break; 2742 case FARG: 2743 /* illegal combination of %s '%s' and %s '%s', arg #%d */ 2744 warning(154, 2745 lx, type_name(ltp), rx, type_name(rtp), arg); 2746 break; 2747 default: 2748 /* illegal combination of %s '%s' and %s '%s', op '%s' */ 2749 warning(123, 2750 lx, type_name(ltp), rx, type_name(rtp), op_name(op)); 2751 break; 2752 } 2753 return true; 2754 } 2755 2756 static bool 2757 check_assign_pointer(op_t op, int arg, 2758 const type_t *ltp, tspec_t lt, 2759 const type_t *rtp, tspec_t rt) 2760 { 2761 if (!(lt == PTR && rt == PTR)) 2762 return false; 2763 2764 switch (op) { 2765 case RETURN: 2766 warn_incompatible_pointers(NULL, ltp, rtp); 2767 break; 2768 case FARG: 2769 /* converting '%s' to incompatible '%s' for ... */ 2770 warning(153, type_name(rtp), type_name(ltp), arg); 2771 break; 2772 default: 2773 warn_incompatible_pointers(&modtab[op], ltp, rtp); 2774 break; 2775 } 2776 return true; 2777 } 2778 2779 static void 2780 warn_assign(op_t op, int arg, 2781 const type_t *ltp, tspec_t lt, 2782 const type_t *rtp, tspec_t rt) 2783 { 2784 switch (op) { 2785 case INIT: 2786 /* cannot initialize '%s' from '%s' */ 2787 error(185, type_name(ltp), type_name(rtp)); 2788 break; 2789 case RETURN: 2790 /* function has return type '%s' but returns '%s' */ 2791 error(211, type_name(ltp), type_name(rtp)); 2792 break; 2793 case FARG: 2794 /* passing '%s' to incompatible '%s', arg #%d */ 2795 warning(155, type_name(rtp), type_name(ltp), arg); 2796 break; 2797 default: 2798 warn_incompatible_types(op, ltp, lt, rtp, rt); 2799 break; 2800 } 2801 } 2802 2803 /* 2804 * Checks type compatibility for ASSIGN, INIT, FARG and RETURN 2805 * and prints warnings/errors if necessary. 2806 * Returns whether the types are (almost) compatible. 2807 */ 2808 static bool 2809 check_assign_types_compatible(op_t op, int arg, 2810 const tnode_t *ln, const tnode_t *rn) 2811 { 2812 tspec_t lt, rt, lst = NOTSPEC, rst = NOTSPEC; 2813 type_t *ltp, *rtp, *lstp = NULL, *rstp = NULL; 2814 2815 if ((lt = (ltp = ln->tn_type)->t_tspec) == PTR) 2816 lst = (lstp = ltp->t_subt)->t_tspec; 2817 if ((rt = (rtp = rn->tn_type)->t_tspec) == PTR) 2818 rst = (rstp = rtp->t_subt)->t_tspec; 2819 2820 if (lt == BOOL && is_scalar(rt)) /* C99 6.3.1.2 */ 2821 return true; 2822 2823 if (is_arithmetic(lt) && (is_arithmetic(rt) || rt == BOOL)) 2824 return true; 2825 2826 if (is_struct_or_union(lt) && is_struct_or_union(rt)) 2827 /* both are struct or union */ 2828 return ltp->t_str == rtp->t_str; 2829 2830 /* a null pointer may be assigned to any pointer */ 2831 if (lt == PTR && is_null_pointer(rn)) 2832 return true; 2833 2834 check_assign_void_pointer(op, arg, lt, lst, rt, rst); 2835 2836 if (check_assign_void_pointer_compat(op, arg, 2837 ltp, lt, lstp, lst, rn, rtp, rt, rstp, rst)) 2838 return true; 2839 2840 if (check_assign_pointer_integer(op, arg, ltp, lt, rtp, rt)) 2841 return true; 2842 2843 if (check_assign_pointer(op, arg, ltp, lt, rtp, rt)) 2844 return true; 2845 2846 warn_assign(op, arg, ltp, lt, rtp, rt); 2847 return false; 2848 } 2849 2850 static bool 2851 has_side_effect(const tnode_t *tn) /* NOLINT(misc-no-recursion) */ 2852 { 2853 op_t op = tn->tn_op; 2854 2855 if (modtab[op].m_has_side_effect) 2856 return true; 2857 2858 if (op == CVT && tn->tn_type->t_tspec == VOID) 2859 return has_side_effect(tn->tn_left); 2860 2861 /* XXX: Why not has_side_effect(tn->tn_left) as well? */ 2862 if (op == LOGAND || op == LOGOR) 2863 return has_side_effect(tn->tn_right); 2864 2865 /* XXX: Why not has_side_effect(tn->tn_left) as well? */ 2866 if (op == QUEST) 2867 return has_side_effect(tn->tn_right); 2868 2869 if (op == COLON || op == COMMA) { 2870 return has_side_effect(tn->tn_left) || 2871 has_side_effect(tn->tn_right); 2872 } 2873 2874 return false; 2875 } 2876 2877 static bool 2878 is_void_cast(const tnode_t *tn) 2879 { 2880 2881 return tn->tn_op == CVT && tn->tn_cast && 2882 tn->tn_type->t_tspec == VOID; 2883 } 2884 2885 static bool 2886 is_local_symbol(const tnode_t *tn) 2887 { 2888 2889 return tn->tn_op == LOAD && 2890 tn->tn_left->tn_op == NAME && 2891 tn->tn_left->tn_sym->s_scl == AUTO; 2892 } 2893 2894 static bool 2895 is_int_constant_zero(const tnode_t *tn) 2896 { 2897 2898 return tn->tn_op == CON && 2899 tn->tn_type->t_tspec == INT && 2900 tn->tn_val->v_quad == 0; 2901 } 2902 2903 static void 2904 check_null_effect(const tnode_t *tn) 2905 { 2906 2907 if (hflag && 2908 !has_side_effect(tn) && 2909 !(is_void_cast(tn) && is_local_symbol(tn->tn_left)) && 2910 !(is_void_cast(tn) && is_int_constant_zero(tn->tn_left))) { 2911 /* expression has null effect */ 2912 warning(129); 2913 } 2914 } 2915 2916 /* 2917 * Check the types for specific operators and type combinations. 2918 * 2919 * At this point, the operands already conform to the type requirements of 2920 * the operator, such as being integer, floating or scalar. 2921 */ 2922 static bool 2923 typeok_op(op_t op, const mod_t *mp, int arg, 2924 const tnode_t *ln, const type_t *ltp, tspec_t lt, 2925 const tnode_t *rn, const type_t *rtp, tspec_t rt) 2926 { 2927 switch (op) { 2928 case ARROW: 2929 return typeok_arrow(lt); 2930 case POINT: 2931 return typeok_point(ln, ltp, lt); 2932 case INCBEF: 2933 case DECBEF: 2934 case INCAFT: 2935 case DECAFT: 2936 return typeok_incdec(op, ln, ltp); 2937 case INDIR: 2938 return typeok_indir(ltp, lt); 2939 case ADDR: 2940 return typeok_address(mp, ln, ltp, lt); 2941 case PLUS: 2942 return typeok_plus(op, ltp, lt, rtp, rt); 2943 case MINUS: 2944 return typeok_minus(op, ltp, lt, rtp, rt); 2945 case SHL: 2946 typeok_shl(mp, lt, rt); 2947 goto shift; 2948 case SHR: 2949 typeok_shr(mp, ln, lt, rn, rt); 2950 shift: 2951 typeok_shift(ltp, lt, rn, rt); 2952 break; 2953 case LT: 2954 case LE: 2955 case GT: 2956 case GE: 2957 compare: 2958 return typeok_compare(op, ln, ltp, lt, rn, rtp, rt); 2959 case EQ: 2960 case NE: 2961 if (is_typeok_eq(ln, lt, rn, rt)) 2962 break; 2963 goto compare; 2964 case QUEST: 2965 return typeok_quest(lt, rn); 2966 case COLON: 2967 return typeok_colon(mp, ln, ltp, lt, rn, rtp, rt); 2968 case ASSIGN: 2969 case INIT: 2970 case FARG: 2971 case RETURN: 2972 if (!check_assign_types_compatible(op, arg, ln, rn)) 2973 return false; 2974 goto assign; 2975 case MULASS: 2976 case DIVASS: 2977 case MODASS: 2978 goto assign; 2979 case ADDASS: 2980 case SUBASS: 2981 if ((lt == PTR && !is_integer(rt)) || rt == PTR) { 2982 warn_incompatible_types(op, ltp, lt, rtp, rt); 2983 return false; 2984 } 2985 goto assign; 2986 case SHLASS: 2987 goto assign; 2988 case SHRASS: 2989 if (pflag && !is_uinteger(lt) && 2990 !(!allow_c90 && is_uinteger(rt))) { 2991 /* bitwise '%s' on signed value possibly nonportable */ 2992 warning(117, mp->m_name); 2993 } 2994 goto assign; 2995 case ANDASS: 2996 case XORASS: 2997 case ORASS: 2998 assign: 2999 return typeok_assign(op, ln, ltp, lt); 3000 case COMMA: 3001 if (!modtab[ln->tn_op].m_has_side_effect) 3002 check_null_effect(ln); 3003 break; 3004 default: 3005 break; 3006 } 3007 return true; 3008 } 3009 3010 /* Prints a warning if a strange operator is used on an enum type. */ 3011 static void 3012 check_bad_enum_operation(op_t op, const tnode_t *ln, const tnode_t *rn) 3013 { 3014 3015 if (!eflag) 3016 return; 3017 3018 /* 3019 * Enum as offset to a pointer is an exception (otherwise enums 3020 * could not be used as array indices). 3021 */ 3022 if (op == PLUS && 3023 ((ln->tn_type->t_is_enum && rn->tn_type->t_tspec == PTR) || 3024 (rn->tn_type->t_is_enum && ln->tn_type->t_tspec == PTR))) { 3025 return; 3026 } 3027 3028 /* dubious operation on enum, op '%s' */ 3029 warning(241, op_name(op)); 3030 } 3031 3032 /* 3033 * Prints a warning if an operator is applied to two different enum types. 3034 */ 3035 static void 3036 check_enum_type_mismatch(op_t op, int arg, const tnode_t *ln, const tnode_t *rn) 3037 { 3038 const mod_t *mp = &modtab[op]; 3039 3040 if (ln->tn_type->t_enum != rn->tn_type->t_enum) { 3041 switch (op) { 3042 case INIT: 3043 /* enum type mismatch between '%s' and '%s' in ... */ 3044 warning(210, 3045 type_name(ln->tn_type), type_name(rn->tn_type)); 3046 break; 3047 case FARG: 3048 /* function expects '%s', passing '%s' for arg #%d */ 3049 warning(156, 3050 type_name(ln->tn_type), type_name(rn->tn_type), 3051 arg); 3052 break; 3053 case RETURN: 3054 /* function has return type '%s' but returns '%s' */ 3055 warning(211, 3056 type_name(ln->tn_type), type_name(rn->tn_type)); 3057 break; 3058 default: 3059 /* enum type mismatch: '%s' '%s' '%s' */ 3060 warning(130, type_name(ln->tn_type), mp->m_name, 3061 type_name(rn->tn_type)); 3062 break; 3063 } 3064 } else if (Pflag && mp->m_comparison && op != EQ && op != NE) { 3065 if (eflag) 3066 /* dubious comparison of enums, op '%s' */ 3067 warning(243, mp->m_name); 3068 } 3069 } 3070 3071 /* Prints a warning if the operands mix between enum and integer. */ 3072 static void 3073 check_enum_int_mismatch(op_t op, int arg, const tnode_t *ln, const tnode_t *rn) 3074 { 3075 3076 if (!eflag) 3077 return; 3078 3079 switch (op) { 3080 case INIT: 3081 /* 3082 * Initialization with 0 is allowed. Otherwise, all implicit 3083 * initializations would need to be warned upon as well. 3084 */ 3085 if (!rn->tn_type->t_is_enum && rn->tn_op == CON && 3086 is_integer(rn->tn_type->t_tspec) && 3087 rn->tn_val->v_quad == 0) { 3088 return; 3089 } 3090 /* initialization of '%s' with '%s' */ 3091 warning(277, type_name(ln->tn_type), type_name(rn->tn_type)); 3092 break; 3093 case FARG: 3094 /* combination of '%s' and '%s', arg #%d */ 3095 warning(278, 3096 type_name(ln->tn_type), type_name(rn->tn_type), arg); 3097 break; 3098 case RETURN: 3099 /* combination of '%s' and '%s' in return */ 3100 warning(279, type_name(ln->tn_type), type_name(rn->tn_type)); 3101 break; 3102 default: 3103 /* combination of '%s' and '%s', op '%s' */ 3104 warning(242, type_name(ln->tn_type), type_name(rn->tn_type), 3105 op_name(op)); 3106 break; 3107 } 3108 } 3109 3110 static void 3111 typeok_enum(op_t op, const mod_t *mp, int arg, 3112 const tnode_t *ln, const type_t *ltp, 3113 const tnode_t *rn, const type_t *rtp) 3114 { 3115 if (mp->m_bad_on_enum && 3116 (ltp->t_is_enum || (mp->m_binary && rtp->t_is_enum))) { 3117 check_bad_enum_operation(op, ln, rn); 3118 } else if (mp->m_valid_on_enum && 3119 (ltp->t_is_enum && rtp != NULL && rtp->t_is_enum)) { 3120 check_enum_type_mismatch(op, arg, ln, rn); 3121 } else if (mp->m_valid_on_enum && 3122 (ltp->t_is_enum || (rtp != NULL && rtp->t_is_enum))) { 3123 check_enum_int_mismatch(op, arg, ln, rn); 3124 } 3125 } 3126 3127 /* Perform most type checks. Return whether the types are ok. */ 3128 bool 3129 typeok(op_t op, int arg, const tnode_t *ln, const tnode_t *rn) 3130 { 3131 tspec_t lt, rt; 3132 type_t *ltp, *rtp; 3133 3134 const mod_t *mp = &modtab[op]; 3135 3136 lint_assert((ltp = ln->tn_type) != NULL); 3137 lt = ltp->t_tspec; 3138 3139 if (mp->m_binary) { 3140 lint_assert((rtp = rn->tn_type) != NULL); 3141 rt = rtp->t_tspec; 3142 } else { 3143 rtp = NULL; 3144 rt = NOTSPEC; 3145 } 3146 3147 if (Tflag && !typeok_scalar_strict_bool(op, mp, arg, ln, rn)) 3148 return false; 3149 if (!typeok_scalar(op, mp, ltp, lt, rtp, rt)) 3150 return false; 3151 3152 if (!typeok_op(op, mp, arg, ln, ltp, lt, rn, rtp, rt)) 3153 return false; 3154 3155 typeok_enum(op, mp, arg, ln, ltp, rn, rtp); 3156 return true; 3157 } 3158 3159 /* In traditional C, keep unsigned and promote FLOAT to DOUBLE. */ 3160 static tspec_t 3161 promote_trad(tspec_t t) 3162 { 3163 3164 if (t == UCHAR || t == USHORT) 3165 return UINT; 3166 if (t == CHAR || t == SCHAR || t == SHORT) 3167 return INT; 3168 if (t == FLOAT) 3169 return DOUBLE; 3170 if (t == ENUM) 3171 return INT; 3172 return t; 3173 } 3174 3175 /* 3176 * C99 6.3.1.1p2 requires for types with lower rank than int that "If an int 3177 * can represent all the values of the original type, the value is converted 3178 * to an int; otherwise it is converted to an unsigned int", and that "All 3179 * other types are unchanged by the integer promotions". 3180 */ 3181 static tspec_t 3182 promote_c90(const tnode_t *tn, tspec_t t, bool farg) 3183 { 3184 if (tn->tn_type->t_bitfield) { 3185 unsigned int len = tn->tn_type->t_flen; 3186 if (len < size_in_bits(INT)) 3187 return INT; 3188 if (len == size_in_bits(INT)) 3189 return is_uinteger(t) ? UINT : INT; 3190 return t; 3191 } 3192 3193 if (t == CHAR || t == SCHAR) 3194 return INT; 3195 if (t == UCHAR) 3196 return size_in_bits(CHAR) < size_in_bits(INT) ? INT : UINT; 3197 if (t == SHORT) 3198 return INT; 3199 if (t == USHORT) 3200 return size_in_bits(SHORT) < size_in_bits(INT) ? INT : UINT; 3201 if (t == ENUM) 3202 return INT; 3203 if (farg && t == FLOAT) 3204 return DOUBLE; 3205 return t; 3206 } 3207 3208 /* 3209 * Performs the "integer promotions" (C99 6.3.1.1p2), which convert small 3210 * integer types to either int or unsigned int. 3211 * 3212 * If allow_c90 is unset or the operand is a function argument with no type 3213 * information (no prototype or variable # of args), converts float to double. 3214 */ 3215 tnode_t * 3216 promote(op_t op, bool farg, tnode_t *tn) 3217 { 3218 3219 tspec_t ot = tn->tn_type->t_tspec; 3220 if (!is_arithmetic(ot)) 3221 return tn; 3222 3223 tspec_t nt = allow_c90 ? promote_c90(tn, ot, farg) : promote_trad(ot); 3224 if (nt == ot) 3225 return tn; 3226 3227 type_t *ntp = expr_dup_type(tn->tn_type); 3228 ntp->t_tspec = nt; 3229 /* 3230 * Keep t_is_enum even though t_tspec gets converted from 3231 * ENUM to INT, so we are later able to check compatibility 3232 * of enum types. 3233 */ 3234 return convert(op, 0, ntp, tn); 3235 } 3236 3237 static void 3238 convert_integer_from_floating(op_t op, const type_t *tp, const tnode_t *tn) 3239 { 3240 3241 if (op == CVT) 3242 /* cast from floating point '%s' to integer '%s' */ 3243 query_message(2, type_name(tn->tn_type), type_name(tp)); 3244 else 3245 /* implicit conversion from floating point '%s' to ... */ 3246 query_message(1, type_name(tn->tn_type), type_name(tp)); 3247 } 3248 3249 static bool 3250 should_warn_about_prototype_conversion(tspec_t nt, 3251 tspec_t ot, const tnode_t *ptn) 3252 { 3253 3254 if (nt == ot) 3255 return false; 3256 3257 if (nt == ENUM && ot == INT) 3258 return false; 3259 3260 if (is_floating(nt) != is_floating(ot) || 3261 portable_size_in_bits(nt) != portable_size_in_bits(ot)) { 3262 /* representation and/or width change */ 3263 if (!is_integer(ot)) 3264 return true; 3265 /* 3266 * XXX: Investigate whether this rule makes sense; see 3267 * tests/usr.bin/xlint/lint1/platform_long.c. 3268 */ 3269 return portable_size_in_bits(ot) > portable_size_in_bits(INT); 3270 } 3271 3272 if (!hflag) 3273 return false; 3274 3275 /* 3276 * If the types differ only in sign and the argument has the same 3277 * representation in both types, print no warning. 3278 */ 3279 if (ptn->tn_op == CON && is_integer(nt) && 3280 signed_type(nt) == signed_type(ot) && 3281 !msb(ptn->tn_val->v_quad, ot)) 3282 return false; 3283 3284 return true; 3285 } 3286 3287 /* 3288 * Warn if a prototype causes a type conversion that is different from what 3289 * would happen to the same argument in the absence of a prototype. This 3290 * check is intended for code that needs to stay compatible with pre-C90 C. 3291 * 3292 * Errors/warnings about illegal type combinations are already printed 3293 * in check_assign_types_compatible(). 3294 */ 3295 static void 3296 check_prototype_conversion(int arg, tspec_t nt, tspec_t ot, type_t *tp, 3297 tnode_t *tn) 3298 { 3299 3300 if (!is_arithmetic(nt) || !is_arithmetic(ot)) 3301 return; 3302 3303 /* 3304 * If the type of the formal parameter is char/short, a warning 3305 * would be useless, because functions declared the old style 3306 * can't expect char/short arguments. 3307 */ 3308 if (nt == CHAR || nt == SCHAR || nt == UCHAR || 3309 nt == SHORT || nt == USHORT) 3310 return; 3311 3312 /* apply the default promotion */ 3313 tnode_t *ptn = promote(NOOP, true, tn); 3314 ot = ptn->tn_type->t_tspec; 3315 3316 if (should_warn_about_prototype_conversion(nt, ot, ptn)) { 3317 /* argument #%d is converted from '%s' to '%s' ... */ 3318 warning(259, arg, type_name(tn->tn_type), type_name(tp)); 3319 } 3320 } 3321 3322 /* 3323 * When converting a large integer type to a small integer type, in some 3324 * cases the value of the actual expression is further restricted than the 3325 * type bounds, such as in (expr & 0xFF) or (expr % 100) or (expr >> 24). 3326 */ 3327 static bool 3328 can_represent(const type_t *tp, const tnode_t *tn) 3329 { 3330 3331 debug_step("%s: type '%s'", __func__, type_name(tp)); 3332 debug_node(tn); 3333 3334 uint64_t nmask = value_bits(width_in_bits(tp)); 3335 if (!is_uinteger(tp->t_tspec)) 3336 nmask >>= 1; 3337 3338 integer_constraints c = ic_expr(tn); 3339 if ((~c.bclr & ~nmask) == 0) 3340 return true; 3341 3342 return false; 3343 } 3344 3345 static void 3346 convert_integer_from_integer(op_t op, int arg, tspec_t nt, tspec_t ot, 3347 type_t *tp, tnode_t *tn) 3348 { 3349 3350 if (tn->tn_op == CON) 3351 return; 3352 3353 if (op == CVT) 3354 return; 3355 3356 if (Pflag && pflag && aflag > 0 && 3357 portable_size_in_bits(nt) > portable_size_in_bits(ot) && 3358 is_uinteger(nt) != is_uinteger(ot)) { 3359 if (op == FARG) { 3360 /* conversion to '%s' may sign-extend ... */ 3361 warning(297, type_name(tp), arg); 3362 } else { 3363 /* conversion to '%s' may sign-extend ... */ 3364 warning(131, type_name(tp)); 3365 } 3366 } 3367 3368 if (Pflag && portable_size_in_bits(nt) > portable_size_in_bits(ot) && 3369 (tn->tn_op == PLUS || tn->tn_op == MINUS || tn->tn_op == MULT || 3370 tn->tn_op == SHL)) { 3371 /* suggest cast from '%s' to '%s' on op '%s' to ... */ 3372 warning(324, type_name(gettyp(ot)), type_name(tp), 3373 op_name(tn->tn_op)); 3374 } 3375 3376 if (aflag > 0 && 3377 portable_size_in_bits(nt) < portable_size_in_bits(ot) && 3378 (ot == LONG || ot == ULONG || ot == QUAD || ot == UQUAD || 3379 aflag > 1) && 3380 !can_represent(tp, tn)) { 3381 if (op == FARG) { 3382 /* conversion from '%s' to '%s' may lose ... */ 3383 warning(298, 3384 type_name(tn->tn_type), type_name(tp), arg); 3385 } else { 3386 /* conversion from '%s' to '%s' may lose accuracy */ 3387 warning(132, 3388 type_name(tn->tn_type), type_name(tp)); 3389 } 3390 } 3391 3392 if (is_uinteger(nt) != is_uinteger(ot)) 3393 /* implicit conversion changes sign from '%s' to '%s' */ 3394 query_message(3, type_name(tn->tn_type), type_name(tp)); 3395 } 3396 3397 static void 3398 convert_integer_from_pointer(op_t op, tspec_t nt, type_t *tp, tnode_t *tn) 3399 { 3400 3401 if (tn->tn_op == CON) 3402 return; 3403 if (op != CVT) 3404 return; /* We got already an error. */ 3405 if (portable_size_in_bits(nt) >= portable_size_in_bits(PTR)) 3406 return; 3407 3408 if (pflag && size_in_bits(nt) >= size_in_bits(PTR)) { 3409 /* conversion of pointer to '%s' may lose bits */ 3410 warning(134, type_name(tp)); 3411 } else { 3412 /* conversion of pointer to '%s' loses bits */ 3413 warning(133, type_name(tp)); 3414 } 3415 } 3416 3417 static bool 3418 struct_starts_with(const type_t *struct_tp, const type_t *member_tp) 3419 { 3420 3421 return struct_tp->t_str->sou_first_member != NULL && 3422 types_compatible(struct_tp->t_str->sou_first_member->s_type, 3423 member_tp, true, false, NULL); 3424 } 3425 3426 static bool 3427 is_byte_array(const type_t *tp) 3428 { 3429 3430 return tp->t_tspec == ARRAY && 3431 (tp->t_subt->t_tspec == CHAR || tp->t_subt->t_tspec == UCHAR); 3432 } 3433 3434 static bool 3435 should_warn_about_pointer_cast(const type_t *nstp, tspec_t nst, 3436 const type_t *ostp, tspec_t ost) 3437 { 3438 3439 while (nst == ARRAY) 3440 nstp = nstp->t_subt, nst = nstp->t_tspec; 3441 while (ost == ARRAY) 3442 ostp = ostp->t_subt, ost = ostp->t_tspec; 3443 3444 if (nst == STRUCT && ost == STRUCT && 3445 (struct_starts_with(nstp, ostp) || 3446 struct_starts_with(ostp, nstp))) 3447 return false; 3448 3449 if (is_incomplete(nstp) || is_incomplete(ostp)) 3450 return false; 3451 3452 if (nst == CHAR || nst == UCHAR) 3453 return false; /* for the sake of traditional C code */ 3454 if (ost == CHAR || ost == UCHAR) 3455 return false; /* for the sake of traditional C code */ 3456 3457 /* Allow cast between pointers to sockaddr variants. */ 3458 if (nst == STRUCT && ost == STRUCT) { 3459 debug_type(nstp); 3460 debug_type(ostp); 3461 const sym_t *nmem = nstp->t_str->sou_first_member; 3462 const sym_t *omem = ostp->t_str->sou_first_member; 3463 while (nmem != NULL && omem != NULL && 3464 types_compatible(nmem->s_type, omem->s_type, 3465 true, false, NULL)) 3466 nmem = nmem->s_next, omem = omem->s_next; 3467 if (nmem != NULL && is_byte_array(nmem->s_type)) 3468 return false; 3469 if (omem != NULL && is_byte_array(omem->s_type)) 3470 return false; 3471 if (nmem == NULL && omem == NULL) 3472 return false; 3473 } 3474 3475 if (is_struct_or_union(nst) && nstp->t_str != ostp->t_str) 3476 return true; 3477 3478 return portable_size_in_bits(nst) != portable_size_in_bits(ost); 3479 } 3480 3481 static void 3482 convert_pointer_from_pointer(type_t *ntp, tnode_t *tn) 3483 { 3484 const type_t *nstp = ntp->t_subt; 3485 const type_t *otp = tn->tn_type; 3486 const type_t *ostp = otp->t_subt; 3487 tspec_t nst = nstp->t_tspec; 3488 tspec_t ost = ostp->t_tspec; 3489 3490 if (nst == VOID || ost == VOID) { 3491 /* TODO: C99 behaves like C90 here. */ 3492 if ((!allow_trad && !allow_c99) && (nst == FUNC || ost == FUNC)) { 3493 const char *nts, *ots; 3494 /* null pointers are already handled in convert() */ 3495 *(nst == FUNC ? &nts : &ots) = "function pointer"; 3496 *(nst == VOID ? &nts : &ots) = "'void *'"; 3497 /* ANSI C forbids conversion of %s to %s */ 3498 warning(303, ots, nts); 3499 } 3500 return; 3501 } 3502 if (nst == FUNC && ost == FUNC) 3503 return; 3504 if (nst == FUNC || ost == FUNC) { 3505 /* converting '%s' to '%s' is questionable */ 3506 warning(229, type_name(otp), type_name(ntp)); 3507 return; 3508 } 3509 3510 if (hflag && alignment_in_bits(nstp) > alignment_in_bits(ostp) && 3511 ost != CHAR && ost != UCHAR && 3512 !is_incomplete(ostp)) { 3513 /* converting '%s' to '%s' increases alignment ... */ 3514 warning(135, type_name(otp), type_name(ntp), 3515 alignment_in_bits(ostp) / CHAR_SIZE, 3516 alignment_in_bits(nstp) / CHAR_SIZE); 3517 } 3518 3519 if (cflag && should_warn_about_pointer_cast(nstp, nst, ostp, ost)) { 3520 /* pointer cast from '%s' to '%s' may be troublesome */ 3521 warning(247, type_name(otp), type_name(ntp)); 3522 } 3523 } 3524 3525 /* 3526 * Insert a conversion operator, which converts the type of the node 3527 * to another given type. 3528 * 3529 * Possible values for 'op': 3530 * CVT a cast-expression 3531 * binary integer promotion for one of the operands, or a usual 3532 * arithmetic conversion 3533 * binary plain or compound assignments to bit-fields 3534 * FARG 'arg' is the number of the argument (used for warnings) 3535 * NOOP several other implicit conversions 3536 * ... 3537 */ 3538 tnode_t * 3539 convert(op_t op, int arg, type_t *tp, tnode_t *tn) 3540 { 3541 tspec_t nt = tp->t_tspec; 3542 tspec_t ot = tn->tn_type->t_tspec; 3543 3544 if (allow_trad && allow_c90 && op == FARG) 3545 check_prototype_conversion(arg, nt, ot, tp, tn); 3546 3547 if (nt == BOOL) { 3548 /* No further checks. */ 3549 3550 } else if (is_integer(nt)) { 3551 if (ot == BOOL) { 3552 /* No further checks. */ 3553 } else if (is_integer(ot)) { 3554 convert_integer_from_integer(op, arg, nt, ot, tp, tn); 3555 } else if (is_floating(ot)) { 3556 convert_integer_from_floating(op, tp, tn); 3557 } else if (ot == PTR) { 3558 convert_integer_from_pointer(op, nt, tp, tn); 3559 } 3560 3561 } else if (is_floating(nt)) { 3562 /* No further checks. */ 3563 3564 } else if (nt == PTR) { 3565 if (is_null_pointer(tn)) { 3566 /* a null pointer may be assigned to any pointer. */ 3567 } else if (ot == PTR && op == CVT) { 3568 convert_pointer_from_pointer(tp, tn); 3569 } 3570 } 3571 3572 tnode_t *ntn = expr_alloc_tnode(); 3573 ntn->tn_op = CVT; 3574 ntn->tn_type = tp; 3575 ntn->tn_cast = op == CVT; 3576 ntn->tn_sys |= tn->tn_sys; 3577 ntn->tn_right = NULL; 3578 if (tn->tn_op != CON || nt == VOID) { 3579 ntn->tn_left = tn; 3580 } else { 3581 ntn->tn_op = CON; 3582 ntn->tn_val = expr_zero_alloc(sizeof(*ntn->tn_val)); 3583 convert_constant(op, arg, ntn->tn_type, ntn->tn_val, 3584 tn->tn_val); 3585 } 3586 3587 return ntn; 3588 } 3589 3590 static void 3591 convert_constant_floating(op_t op, int arg, tspec_t ot, const type_t *tp, 3592 tspec_t nt, val_t *v, val_t *nv) 3593 { 3594 ldbl_t max = 0.0, min = 0.0; 3595 3596 switch (nt) { 3597 case CHAR: 3598 max = TARG_CHAR_MAX; min = TARG_CHAR_MIN; break; 3599 case UCHAR: 3600 max = TARG_UCHAR_MAX; min = 0; break; 3601 case SCHAR: 3602 max = TARG_SCHAR_MAX; min = TARG_SCHAR_MIN; break; 3603 case SHORT: 3604 max = TARG_SHRT_MAX; min = TARG_SHRT_MIN; break; 3605 case USHORT: 3606 max = TARG_USHRT_MAX; min = 0; break; 3607 case ENUM: 3608 case INT: 3609 max = TARG_INT_MAX; min = TARG_INT_MIN; break; 3610 case UINT: 3611 max = TARG_UINT_MAX; min = 0; break; 3612 case LONG: 3613 max = TARG_LONG_MAX; min = TARG_LONG_MIN; break; 3614 case ULONG: 3615 max = TARG_ULONG_MAX; min = 0; break; 3616 case QUAD: 3617 max = QUAD_MAX; min = QUAD_MIN; break; 3618 case UQUAD: 3619 max = UQUAD_MAX; min = 0; break; 3620 case FLOAT: 3621 case FCOMPLEX: 3622 max = FLT_MAX; min = -FLT_MAX; break; 3623 case DOUBLE: 3624 case DCOMPLEX: 3625 max = DBL_MAX; min = -DBL_MAX; break; 3626 case PTR: 3627 /* Got already an error because of float --> ptr */ 3628 case LDOUBLE: 3629 case LCOMPLEX: 3630 /* LINTED 248 */ 3631 max = LDBL_MAX; min = -max; break; 3632 default: 3633 lint_assert(/*CONSTCOND*/false); 3634 } 3635 if (v->v_ldbl > max || v->v_ldbl < min) { 3636 lint_assert(nt != LDOUBLE); 3637 if (op == FARG) { 3638 /* conversion of '%s' to '%s' is out of range, ... */ 3639 warning(295, 3640 type_name(gettyp(ot)), type_name(tp), arg); 3641 } else { 3642 /* conversion of '%s' to '%s' is out of range */ 3643 warning(119, 3644 type_name(gettyp(ot)), type_name(tp)); 3645 } 3646 v->v_ldbl = v->v_ldbl > 0 ? max : min; 3647 } 3648 3649 if (nt == FLOAT || nt == FCOMPLEX) { 3650 nv->v_ldbl = (float)v->v_ldbl; 3651 } else if (nt == DOUBLE || nt == DCOMPLEX) { 3652 nv->v_ldbl = (double)v->v_ldbl; 3653 } else if (nt == LDOUBLE || nt == LCOMPLEX) { 3654 nv->v_ldbl = v->v_ldbl; 3655 } else { 3656 nv->v_quad = (int64_t)v->v_ldbl; 3657 } 3658 } 3659 3660 static bool 3661 convert_constant_to_floating(tspec_t nt, val_t *nv, 3662 tspec_t ot, const val_t *v) 3663 { 3664 if (nt == FLOAT) { 3665 nv->v_ldbl = (ot == PTR || is_uinteger(ot)) ? 3666 (float)(uint64_t)v->v_quad : (float)v->v_quad; 3667 } else if (nt == DOUBLE) { 3668 nv->v_ldbl = (ot == PTR || is_uinteger(ot)) ? 3669 (double)(uint64_t)v->v_quad : (double)v->v_quad; 3670 } else if (nt == LDOUBLE) { 3671 nv->v_ldbl = (ot == PTR || is_uinteger(ot)) ? 3672 (ldbl_t)(uint64_t)v->v_quad : (ldbl_t)v->v_quad; 3673 } else 3674 return false; 3675 return true; 3676 } 3677 3678 /* 3679 * Print a warning if bits which were set are lost due to the conversion. 3680 * This can happen with operator ORASS only. 3681 */ 3682 static void 3683 convert_constant_check_range_bitor(size_t nsz, size_t osz, const val_t *v, 3684 uint64_t xmask, op_t op) 3685 { 3686 if (nsz < osz && (v->v_quad & xmask) != 0) { 3687 /* constant truncated by conversion, op '%s' */ 3688 warning(306, op_name(op)); 3689 } 3690 } 3691 3692 /* 3693 * Print a warning if additional bits are not all 1 3694 * and the most significant bit of the old value is 1, 3695 * or if at least one (but not all) removed bit was 0. 3696 */ 3697 static void 3698 convert_constant_check_range_bitand(size_t nsz, size_t osz, 3699 uint64_t xmask, const val_t *nv, 3700 tspec_t ot, const val_t *v, 3701 const type_t *tp, op_t op) 3702 { 3703 if (nsz > osz && 3704 (nv->v_quad & bit((unsigned int)(osz - 1))) != 0 && 3705 (nv->v_quad & xmask) != xmask) { 3706 /* extra bits set to 0 in conversion of '%s' to '%s', ... */ 3707 warning(309, type_name(gettyp(ot)), 3708 type_name(tp), op_name(op)); 3709 } else if (nsz < osz && 3710 (v->v_quad & xmask) != xmask && 3711 (v->v_quad & xmask) != 0) { 3712 /* constant truncated by conversion, op '%s' */ 3713 warning(306, op_name(op)); 3714 } 3715 } 3716 3717 static void 3718 convert_constant_check_range_signed(op_t op, int arg) 3719 { 3720 if (op == ASSIGN) { 3721 /* assignment of negative constant to unsigned type */ 3722 warning(164); 3723 } else if (op == INIT) { 3724 /* initialization of unsigned with negative constant */ 3725 warning(221); 3726 } else if (op == FARG) { 3727 /* conversion of negative constant to unsigned type, ... */ 3728 warning(296, arg); 3729 } else if (modtab[op].m_comparison) { 3730 /* handled by check_integer_comparison() */ 3731 } else { 3732 /* conversion of negative constant to unsigned type */ 3733 warning(222); 3734 } 3735 } 3736 3737 /* 3738 * Loss of significant bit(s). All truncated bits of unsigned types or all 3739 * truncated bits plus the msb of the target for signed types are considered 3740 * to be significant bits. Loss of significant bits means that at least one 3741 * of the bits was set in an unsigned type or that at least one but not all 3742 * of the bits was set in a signed type. Loss of significant bits means that 3743 * it is not possible, also not with necessary casts, to convert back to the 3744 * original type. A example for a necessary cast is: 3745 * char c; int i; c = 128; 3746 * i = c; ** yields -128 ** 3747 * i = (unsigned char)c; ** yields 128 ** 3748 */ 3749 static void 3750 convert_constant_check_range_truncated(op_t op, int arg, const type_t *tp, 3751 tspec_t ot) 3752 { 3753 if (op == ASSIGN && tp->t_bitfield) { 3754 /* precision lost in bit-field assignment */ 3755 warning(166); 3756 } else if (op == ASSIGN) { 3757 /* constant truncated by assignment */ 3758 warning(165); 3759 } else if (op == INIT && tp->t_bitfield) { 3760 /* bit-field initializer does not fit */ 3761 warning(180); 3762 } else if (op == INIT) { 3763 /* initializer does not fit */ 3764 warning(178); 3765 } else if (op == CASE) { 3766 /* case label affected by conversion */ 3767 warning(196); 3768 } else if (op == FARG) { 3769 /* conversion of '%s' to '%s' is out of range, arg #%d */ 3770 warning(295, 3771 type_name(gettyp(ot)), type_name(tp), arg); 3772 } else { 3773 /* conversion of '%s' to '%s' is out of range */ 3774 warning(119, 3775 type_name(gettyp(ot)), type_name(tp)); 3776 } 3777 } 3778 3779 static void 3780 convert_constant_check_range_loss(op_t op, int arg, const type_t *tp, 3781 tspec_t ot) 3782 { 3783 if (op == ASSIGN && tp->t_bitfield) { 3784 /* precision lost in bit-field assignment */ 3785 warning(166); 3786 } else if (op == INIT && tp->t_bitfield) { 3787 /* bit-field initializer out of range */ 3788 warning(11); 3789 } else if (op == CASE) { 3790 /* case label affected by conversion */ 3791 warning(196); 3792 } else if (op == FARG) { 3793 /* conversion of '%s' to '%s' is out of range, arg #%d */ 3794 warning(295, type_name(gettyp(ot)), type_name(tp), arg); 3795 } else { 3796 /* conversion of '%s' to '%s' is out of range */ 3797 warning(119, type_name(gettyp(ot)), type_name(tp)); 3798 } 3799 } 3800 3801 static void 3802 convert_constant_check_range(tspec_t ot, const type_t *tp, tspec_t nt, 3803 op_t op, int arg, const val_t *v, val_t *nv) 3804 { 3805 unsigned int obitsz, nbitsz; 3806 uint64_t xmask, xmsk1; 3807 3808 obitsz = size_in_bits(ot); 3809 nbitsz = tp->t_bitfield ? tp->t_flen : size_in_bits(nt); 3810 xmask = value_bits(nbitsz) ^ value_bits(obitsz); 3811 xmsk1 = value_bits(nbitsz) ^ value_bits(obitsz - 1); 3812 /* 3813 * For bitwise operations we are not interested in the arithmetic 3814 * value, but in the bits itself. 3815 */ 3816 if (op == ORASS || op == BITOR || op == BITXOR) { 3817 convert_constant_check_range_bitor( 3818 nbitsz, obitsz, v, xmask, op); 3819 } else if (op == ANDASS || op == BITAND) { 3820 convert_constant_check_range_bitand( 3821 nbitsz, obitsz, xmask, nv, ot, v, tp, op); 3822 } else if ((nt != PTR && is_uinteger(nt)) && 3823 (ot != PTR && !is_uinteger(ot)) && 3824 v->v_quad < 0) { 3825 convert_constant_check_range_signed(op, arg); 3826 } else if (nv->v_quad != v->v_quad && nbitsz <= obitsz && 3827 (v->v_quad & xmask) != 0 && 3828 (is_uinteger(ot) || (v->v_quad & xmsk1) != xmsk1)) { 3829 convert_constant_check_range_truncated(op, arg, tp, ot); 3830 } else if (nv->v_quad != v->v_quad) { 3831 convert_constant_check_range_loss(op, arg, tp, ot); 3832 } 3833 } 3834 3835 /* 3836 * Converts a typed constant to a constant of another type. 3837 * 3838 * op operator which requires conversion 3839 * arg if op is FARG, # of argument 3840 * tp type in which to convert the constant 3841 * nv new constant 3842 * v old constant 3843 */ 3844 void 3845 convert_constant(op_t op, int arg, const type_t *tp, val_t *nv, val_t *v) 3846 { 3847 /* 3848 * TODO: make 'v' const; the name of this function does not suggest 3849 * that it modifies 'v'. 3850 */ 3851 tspec_t ot = v->v_tspec; 3852 tspec_t nt = nv->v_tspec = tp->t_tspec; 3853 bool range_check = false; 3854 3855 if (nt == BOOL) { /* C99 6.3.1.2 */ 3856 nv->v_unsigned_since_c90 = false; 3857 nv->v_quad = is_nonzero_val(v) ? 1 : 0; 3858 return; 3859 } 3860 3861 if (ot == FLOAT || ot == DOUBLE || ot == LDOUBLE) { 3862 convert_constant_floating(op, arg, ot, tp, nt, v, nv); 3863 } else if (!convert_constant_to_floating(nt, nv, ot, v)) { 3864 range_check = true; /* Check for lost precision. */ 3865 nv->v_quad = v->v_quad; 3866 } 3867 3868 if (allow_trad && allow_c90 && v->v_unsigned_since_c90 && 3869 (is_floating(nt) || ( 3870 (is_integer(nt) && !is_uinteger(nt) && 3871 portable_size_in_bits(nt) > portable_size_in_bits(ot))))) { 3872 /* ANSI C treats constant as unsigned */ 3873 warning(157); 3874 v->v_unsigned_since_c90 = false; 3875 } 3876 3877 if (is_integer(nt)) { 3878 nv->v_quad = convert_integer(nv->v_quad, nt, 3879 tp->t_bitfield ? tp->t_flen : size_in_bits(nt)); 3880 } 3881 3882 if (range_check && op != CVT) 3883 convert_constant_check_range(ot, tp, nt, op, arg, v, nv); 3884 } 3885 3886 /* 3887 * Create a constant node for sizeof. 3888 */ 3889 tnode_t * 3890 build_sizeof(const type_t *tp) 3891 { 3892 unsigned int size_in_bytes = type_size_in_bits(tp) / CHAR_SIZE; 3893 tnode_t *tn = build_integer_constant(SIZEOF_TSPEC, size_in_bytes); 3894 tn->tn_system_dependent = true; 3895 debug_step("build_sizeof '%s' = %u", type_name(tp), size_in_bytes); 3896 return tn; 3897 } 3898 3899 /* 3900 * Create a constant node for offsetof. 3901 */ 3902 /* ARGSUSED */ /* FIXME: See implementation comments. */ 3903 tnode_t * 3904 build_offsetof(const type_t *tp, const sym_t *sym) 3905 { 3906 unsigned int offset_in_bytes; 3907 tnode_t *tn; 3908 3909 if (!is_struct_or_union(tp->t_tspec)) 3910 /* unacceptable operand of '%s' */ 3911 error(111, "offsetof"); 3912 3913 /* FIXME: Don't wrongly use the size of the whole type, use sym. */ 3914 offset_in_bytes = type_size_in_bits(tp) / CHAR_SIZE; 3915 tn = build_integer_constant(SIZEOF_TSPEC, offset_in_bytes); 3916 tn->tn_system_dependent = true; 3917 return tn; 3918 } 3919 3920 unsigned int 3921 type_size_in_bits(const type_t *tp) 3922 { 3923 unsigned int elsz; 3924 3925 unsigned int elem = 1; 3926 bool flex = false; 3927 lint_assert(tp != NULL); 3928 while (tp->t_tspec == ARRAY) { 3929 flex = true; /* allow c99 flex arrays [] [0] */ 3930 elem *= tp->t_dim; 3931 tp = tp->t_subt; 3932 } 3933 if (elem == 0) { 3934 if (!flex) { 3935 /* cannot take size/alignment of incomplete type */ 3936 error(143); 3937 elem = 1; 3938 } 3939 } 3940 switch (tp->t_tspec) { 3941 case FUNC: 3942 /* cannot take size/alignment of function type '%s' */ 3943 error(144, type_name(tp)); 3944 elsz = 1; 3945 break; 3946 case STRUCT: 3947 case UNION: 3948 if (is_incomplete(tp)) { 3949 /* cannot take size/alignment of incomplete type */ 3950 error(143); 3951 elsz = 1; 3952 } else { 3953 elsz = tp->t_str->sou_size_in_bits; 3954 } 3955 break; 3956 case ENUM: 3957 if (is_incomplete(tp)) { 3958 /* cannot take size/alignment of incomplete type */ 3959 warning(143); 3960 } 3961 /* FALLTHROUGH */ 3962 default: 3963 if (tp->t_bitfield) { 3964 /* cannot take size/alignment of bit-field */ 3965 error(145); 3966 } 3967 if (tp->t_tspec == VOID) { 3968 /* cannot take size/alignment of void */ 3969 error(146); 3970 elsz = 1; 3971 } else { 3972 elsz = size_in_bits(tp->t_tspec); 3973 lint_assert(elsz > 0); 3974 } 3975 break; 3976 } 3977 3978 return elem * elsz; 3979 } 3980 3981 tnode_t * 3982 build_alignof(const type_t *tp) 3983 { 3984 switch (tp->t_tspec) { 3985 case ARRAY: 3986 break; 3987 3988 case FUNC: 3989 /* cannot take size/alignment of function type '%s' */ 3990 error(144, type_name(tp)); 3991 return 0; 3992 3993 case STRUCT: 3994 case UNION: 3995 if (is_incomplete(tp)) { 3996 /* cannot take size/alignment of incomplete type */ 3997 error(143); 3998 return 0; 3999 } 4000 break; 4001 case ENUM: 4002 break; 4003 default: 4004 if (tp->t_bitfield) { 4005 /* cannot take size/alignment of bit-field */ 4006 error(145); 4007 return 0; 4008 } 4009 if (tp->t_tspec == VOID) { 4010 /* cannot take size/alignment of void */ 4011 error(146); 4012 return 0; 4013 } 4014 break; 4015 } 4016 4017 return build_integer_constant(SIZEOF_TSPEC, 4018 (int64_t)alignment_in_bits(tp) / CHAR_SIZE); 4019 } 4020 4021 static tnode_t * 4022 cast_to_union(const tnode_t *otn, type_t *ntp) 4023 { 4024 4025 if (!allow_gcc) { 4026 /* union cast is a GCC extension */ 4027 error(328); 4028 return NULL; 4029 } 4030 4031 for (const sym_t *m = ntp->t_str->sou_first_member; 4032 m != NULL; m = m->s_next) { 4033 if (types_compatible(m->s_type, otn->tn_type, 4034 false, false, NULL)) { 4035 tnode_t *ntn = expr_alloc_tnode(); 4036 ntn->tn_op = CVT; 4037 ntn->tn_type = ntp; 4038 ntn->tn_cast = true; 4039 ntn->tn_right = NULL; 4040 return ntn; 4041 } 4042 } 4043 4044 /* type '%s' is not a member of '%s' */ 4045 error(329, type_name(otn->tn_type), type_name(ntp)); 4046 return NULL; 4047 } 4048 4049 /* 4050 * Type casts. 4051 */ 4052 tnode_t * 4053 cast(tnode_t *tn, type_t *tp) 4054 { 4055 tspec_t nt, ot; 4056 4057 if (tn == NULL) 4058 return NULL; 4059 4060 tn = cconv(tn); 4061 4062 lint_assert(tp != NULL); 4063 nt = tp->t_tspec; 4064 ot = tn->tn_type->t_tspec; 4065 4066 if (nt == VOID) { 4067 /* 4068 * C90 6.3.4, C99 6.5.4p2 and C11 6.5.4p2 allow any type to 4069 * be cast to void. The only other allowed casts are from a 4070 * scalar type to a scalar type. 4071 */ 4072 } else if (nt == UNION) { 4073 return cast_to_union(tn, tp); 4074 } else if (nt == STRUCT || nt == ARRAY || nt == FUNC) { 4075 /* Casting to a struct is an undocumented GCC extension. */ 4076 if (!(allow_gcc && nt == STRUCT)) 4077 goto invalid_cast; 4078 } else if (is_struct_or_union(ot)) { 4079 goto invalid_cast; 4080 } else if (ot == VOID) { 4081 /* improper cast of void expression */ 4082 error(148); 4083 return NULL; 4084 } else if (is_integer(nt) && is_scalar(ot)) { 4085 /* ok */ 4086 } else if (is_floating(nt) && is_arithmetic(ot)) { 4087 /* ok */ 4088 } else if (nt == PTR && is_integer(ot)) { 4089 /* ok */ 4090 } else if (nt == PTR && ot == PTR) { 4091 if (!tp->t_subt->t_const && tn->tn_type->t_subt->t_const) { 4092 if (hflag) 4093 /* cast discards 'const' from type '%s' */ 4094 warning(275, type_name(tn->tn_type)); 4095 } 4096 } else 4097 goto invalid_cast; 4098 4099 if (any_query_enabled && types_compatible(tp, tn->tn_type, 4100 false, false, NULL)) { 4101 /* no-op cast from '%s' to '%s' */ 4102 query_message(6, type_name(tn->tn_type), type_name(tp)); 4103 } 4104 4105 tn = convert(CVT, 0, tp, tn); 4106 tn->tn_cast = true; 4107 4108 return tn; 4109 4110 invalid_cast: 4111 /* invalid cast from '%s' to '%s' */ 4112 error(147, type_name(tn->tn_type), type_name(tp)); 4113 return NULL; 4114 } 4115 4116 /* 4117 * Create the node for a function argument. 4118 * All necessary conversions and type checks are done in 4119 * build_function_call because build_function_argument has no 4120 * information about expected argument types. 4121 */ 4122 tnode_t * 4123 build_function_argument(tnode_t *args, tnode_t *arg) 4124 { 4125 /* 4126 * If there was a serious error in the expression for the argument, 4127 * create a dummy argument so the positions of the remaining arguments 4128 * will not change. 4129 */ 4130 if (arg == NULL) 4131 arg = build_integer_constant(INT, 0); 4132 4133 return new_tnode(PUSH, arg->tn_sys, arg->tn_type, arg, args); 4134 } 4135 4136 /* 4137 * Compare the type of an argument with the corresponding type of a 4138 * prototype parameter. If it is a valid combination, but both types 4139 * are not the same, insert a conversion to convert the argument into 4140 * the type of the parameter. 4141 */ 4142 static tnode_t * 4143 check_prototype_argument( 4144 int n, /* pos of arg */ 4145 type_t *tp, /* expected type (from prototype) */ 4146 tnode_t *tn) /* argument */ 4147 { 4148 tnode_t *ln = xcalloc(1, sizeof(*ln)); 4149 ln->tn_type = expr_unqualified_type(tp); 4150 ln->tn_lvalue = true; 4151 if (typeok(FARG, n, ln, tn)) { 4152 bool dowarn; 4153 if (!types_compatible(tp, tn->tn_type, 4154 true, false, (dowarn = false, &dowarn)) || dowarn) 4155 tn = convert(FARG, n, tp, tn); 4156 } 4157 free(ln); 4158 return tn; 4159 } 4160 4161 /* 4162 * Check types of all function arguments and insert conversions, 4163 * if necessary. 4164 */ 4165 static tnode_t * 4166 check_function_arguments(type_t *ftp, tnode_t *args) 4167 { 4168 tnode_t *arg; 4169 sym_t *asym; 4170 tspec_t at; 4171 int narg, npar, n, i; 4172 4173 /* get # of args in the prototype */ 4174 npar = 0; 4175 for (asym = ftp->t_args; asym != NULL; asym = asym->s_next) 4176 npar++; 4177 4178 /* get # of args in function call */ 4179 narg = 0; 4180 for (arg = args; arg != NULL; arg = arg->tn_right) 4181 narg++; 4182 4183 asym = ftp->t_args; 4184 if (ftp->t_proto && npar != narg && !(ftp->t_vararg && npar < narg)) { 4185 /* argument mismatch: %d %s passed, %d expected */ 4186 error(150, narg, narg > 1 ? "arguments" : "argument", npar); 4187 asym = NULL; 4188 } 4189 4190 for (n = 1; n <= narg; n++) { 4191 4192 /* 4193 * The rightmost argument is at the top of the argument 4194 * subtree. 4195 */ 4196 for (i = narg, arg = args; i > n; i--, arg = arg->tn_right) 4197 continue; 4198 4199 /* some things which are always not allowed */ 4200 if ((at = arg->tn_left->tn_type->t_tspec) == VOID) { 4201 /* void expressions may not be arguments, arg #%d */ 4202 error(151, n); 4203 return NULL; 4204 } else if (is_struct_or_union(at) && 4205 is_incomplete(arg->tn_left->tn_type)) { 4206 /* argument cannot have unknown size, arg #%d */ 4207 error(152, n); 4208 return NULL; 4209 } else if (is_integer(at) && 4210 arg->tn_left->tn_type->t_is_enum && 4211 is_incomplete(arg->tn_left->tn_type)) { 4212 /* argument cannot have unknown size, arg #%d */ 4213 warning(152, n); 4214 } 4215 4216 /* class conversions (arg in value context) */ 4217 arg->tn_left = cconv(arg->tn_left); 4218 4219 if (asym != NULL) { 4220 arg->tn_left = check_prototype_argument( 4221 n, asym->s_type, arg->tn_left); 4222 } else { 4223 arg->tn_left = promote(NOOP, true, arg->tn_left); 4224 } 4225 arg->tn_type = arg->tn_left->tn_type; 4226 4227 if (asym != NULL) 4228 asym = asym->s_next; 4229 } 4230 4231 return args; 4232 } 4233 4234 /* 4235 * Create the node for a function call. Also check types of 4236 * function arguments and insert conversions, if necessary. 4237 */ 4238 tnode_t * 4239 build_function_call(tnode_t *func, bool sys, tnode_t *args) 4240 { 4241 tnode_t *ntn; 4242 op_t fcop; 4243 4244 if (func == NULL) 4245 return NULL; 4246 4247 if (func->tn_op == NAME && func->tn_type->t_tspec == FUNC) { 4248 fcop = CALL; 4249 } else { 4250 fcop = ICALL; 4251 } 4252 4253 check_ctype_function_call(func, args); 4254 4255 /* 4256 * after cconv() func will always be a pointer to a function 4257 * if it is a valid function designator. 4258 */ 4259 func = cconv(func); 4260 4261 if (func->tn_type->t_tspec != PTR || 4262 func->tn_type->t_subt->t_tspec != FUNC) { 4263 /* cannot call '%s', must be a function */ 4264 error(149, type_name(func->tn_type)); 4265 return NULL; 4266 } 4267 4268 args = check_function_arguments(func->tn_type->t_subt, args); 4269 4270 ntn = new_tnode(fcop, sys, func->tn_type->t_subt->t_subt, func, args); 4271 4272 return ntn; 4273 } 4274 4275 /* 4276 * Return the value of an integral constant expression. 4277 * If the expression is not constant or its type is not an integer 4278 * type, an error message is printed. 4279 */ 4280 val_t * 4281 constant(tnode_t *tn, bool required) 4282 { 4283 4284 if (tn != NULL) 4285 tn = cconv(tn); 4286 if (tn != NULL) 4287 tn = promote(NOOP, false, tn); 4288 4289 val_t *v = xcalloc(1, sizeof(*v)); 4290 4291 if (tn == NULL) { 4292 lint_assert(nerr != 0); 4293 debug_step("constant node is null; returning 1 instead"); 4294 v->v_tspec = INT; 4295 v->v_quad = 1; 4296 return v; 4297 } 4298 4299 v->v_tspec = tn->tn_type->t_tspec; 4300 4301 if (tn->tn_op == CON) { 4302 lint_assert(tn->tn_type->t_tspec == tn->tn_val->v_tspec); 4303 if (is_integer(tn->tn_val->v_tspec)) { 4304 v->v_unsigned_since_c90 = 4305 tn->tn_val->v_unsigned_since_c90; 4306 v->v_quad = tn->tn_val->v_quad; 4307 return v; 4308 } 4309 v->v_quad = tn->tn_val->v_ldbl; 4310 } else { 4311 v->v_quad = 1; 4312 } 4313 4314 if (required) 4315 /* integral constant expression expected */ 4316 error(55); 4317 else 4318 /* variable array dimension is a C99/GCC extension */ 4319 c99ism(318); 4320 4321 if (!is_integer(v->v_tspec)) 4322 v->v_tspec = INT; 4323 4324 return v; 4325 } 4326 4327 static bool 4328 is_constcond_false(const tnode_t *tn, tspec_t t) 4329 { 4330 return (t == BOOL || t == INT) && 4331 tn->tn_op == CON && tn->tn_val->v_quad == 0; 4332 } 4333 4334 /* 4335 * Perform some tests on expressions which can't be done in build_binary() 4336 * and functions called by build_binary(). These tests must be done here 4337 * because we need some information about the context in which the operations 4338 * are performed. 4339 * After all tests are performed and dofreeblk is true, expr() frees the 4340 * memory which is used for the expression. 4341 */ 4342 void 4343 expr(tnode_t *tn, bool vctx, bool cond, bool dofreeblk, bool is_do_while) 4344 { 4345 4346 if (tn == NULL) { /* in case of errors */ 4347 expr_free_all(); 4348 return; 4349 } 4350 4351 /* expr() is also called in global initializations */ 4352 if (dcs->d_kind != DK_EXTERN && !is_do_while) 4353 check_statement_reachable(); 4354 4355 check_expr_misc(tn, vctx, cond, !cond, false, false, false); 4356 if (tn->tn_op == ASSIGN) { 4357 if (hflag && cond) 4358 /* assignment in conditional context */ 4359 warning(159); 4360 } else if (tn->tn_op == CON) { 4361 if (hflag && cond && !constcond_flag && 4362 !tn->tn_system_dependent && 4363 !(is_do_while && 4364 is_constcond_false(tn, tn->tn_type->t_tspec))) 4365 /* constant in conditional context */ 4366 warning(161); 4367 } 4368 if (!modtab[tn->tn_op].m_has_side_effect) { 4369 /* 4370 * for left operands of COMMA this warning is already 4371 * printed 4372 */ 4373 if (tn->tn_op != COMMA && !vctx && !cond) 4374 check_null_effect(tn); 4375 } 4376 debug_node(tn); 4377 4378 /* free the tree memory */ 4379 if (dofreeblk) 4380 expr_free_all(); 4381 } 4382 4383 /* 4384 * Checks the range of array indices, if possible. 4385 * amper is set if only the address of the element is used. This 4386 * means that the index is allowed to refer to the first element 4387 * after the array. 4388 */ 4389 static void 4390 check_array_index(tnode_t *tn, bool amper) 4391 { 4392 const tnode_t *ln = tn->tn_left; 4393 const tnode_t *rn = tn->tn_right; 4394 4395 /* We can only check constant indices. */ 4396 if (rn->tn_op != CON) 4397 return; 4398 4399 /* Return if the left node does not stem from an array. */ 4400 if (ln->tn_op != ADDR) 4401 return; 4402 if (ln->tn_left->tn_op != STRING && ln->tn_left->tn_op != NAME) 4403 return; 4404 if (ln->tn_left->tn_type->t_tspec != ARRAY) 4405 return; 4406 4407 /* 4408 * For incomplete array types, we can print a warning only if 4409 * the index is negative. 4410 */ 4411 if (is_incomplete(ln->tn_left->tn_type) && rn->tn_val->v_quad >= 0) 4412 return; 4413 4414 /* Get the size of one array element */ 4415 int elsz = length_in_bits(ln->tn_type->t_subt, NULL); 4416 if (elsz == 0) 4417 return; 4418 elsz /= CHAR_SIZE; 4419 4420 /* Change the unit of the index from bytes to element size. */ 4421 int64_t con; 4422 if (is_uinteger(rn->tn_type->t_tspec)) 4423 con = (uint64_t)rn->tn_val->v_quad / elsz; 4424 else 4425 con = rn->tn_val->v_quad / elsz; 4426 4427 int dim = ln->tn_left->tn_type->t_dim + (amper ? 1 : 0); 4428 4429 if (!is_uinteger(rn->tn_type->t_tspec) && con < 0) { 4430 /* array subscript cannot be negative: %ld */ 4431 warning(167, (long)con); 4432 } else if (dim > 0 && (uint64_t)con >= (uint64_t)dim) { 4433 /* array subscript cannot be > %d: %ld */ 4434 warning(168, dim - 1, (long)con); 4435 } 4436 } 4437 4438 static void 4439 check_expr_addr(const tnode_t *ln, bool szof, bool fcall) 4440 { 4441 /* XXX: Taking warn_about_unreachable into account here feels wrong. */ 4442 if (ln->tn_op == NAME && (reached || !warn_about_unreachable)) { 4443 if (!szof) 4444 mark_as_set(ln->tn_sym); 4445 mark_as_used(ln->tn_sym, fcall, szof); 4446 } 4447 if (ln->tn_op == INDIR && ln->tn_left->tn_op == PLUS) 4448 /* check the range of array indices */ 4449 check_array_index(ln->tn_left, true); 4450 } 4451 4452 static void 4453 check_expr_load(const tnode_t *ln) 4454 { 4455 if (ln->tn_op == INDIR && ln->tn_left->tn_op == PLUS) 4456 /* check the range of array indices */ 4457 check_array_index(ln->tn_left, false); 4458 } 4459 4460 static void 4461 check_expr_side_effect(const tnode_t *ln, bool szof) 4462 { 4463 dinfo_t *di; 4464 4465 /* XXX: Taking warn_about_unreachable into account here feels wrong. */ 4466 if (ln->tn_op == NAME && (reached || !warn_about_unreachable)) { 4467 scl_t sc = ln->tn_sym->s_scl; 4468 /* 4469 * Look if there was a asm statement in one of the 4470 * compound statements we are in. If not, we don't 4471 * print a warning. 4472 */ 4473 for (di = dcs; di != NULL; di = di->d_enclosing) { 4474 if (di->d_asm) 4475 break; 4476 } 4477 if (sc != EXTERN && sc != STATIC && 4478 !ln->tn_sym->s_set && !szof && di == NULL) { 4479 /* '%s' may be used before set */ 4480 warning(158, ln->tn_sym->s_name); 4481 mark_as_set(ln->tn_sym); 4482 } 4483 mark_as_used(ln->tn_sym, false, false); 4484 } 4485 } 4486 4487 static void 4488 check_expr_assign(const tnode_t *ln, bool szof) 4489 { 4490 /* XXX: Taking warn_about_unreachable into account here feels wrong. */ 4491 if (ln->tn_op == NAME && !szof && (reached || !warn_about_unreachable)) { 4492 mark_as_set(ln->tn_sym); 4493 if (ln->tn_sym->s_scl == EXTERN) 4494 outusg(ln->tn_sym); 4495 } 4496 if (ln->tn_op == INDIR && ln->tn_left->tn_op == PLUS) 4497 /* check the range of array indices */ 4498 check_array_index(ln->tn_left, false); 4499 } 4500 4501 static void 4502 check_expr_call(const tnode_t *tn, const tnode_t *ln, 4503 bool szof, bool vctx, bool cond, bool retval_discarded) 4504 { 4505 lint_assert(ln->tn_op == ADDR); 4506 lint_assert(ln->tn_left->tn_op == NAME); 4507 if (!szof && 4508 !is_compiler_builtin(ln->tn_left->tn_sym->s_name)) 4509 outcall(tn, vctx || cond, retval_discarded); 4510 } 4511 4512 static bool 4513 check_expr_op(const tnode_t *tn, op_t op, const tnode_t *ln, 4514 bool szof, bool fcall, bool vctx, bool cond, 4515 bool retval_discarded, bool eqwarn) 4516 { 4517 switch (op) { 4518 case ADDR: 4519 check_expr_addr(ln, szof, fcall); 4520 break; 4521 case LOAD: 4522 check_expr_load(ln); 4523 /* FALLTHROUGH */ 4524 case PUSH: 4525 case INCBEF: 4526 case DECBEF: 4527 case INCAFT: 4528 case DECAFT: 4529 case ADDASS: 4530 case SUBASS: 4531 case MULASS: 4532 case DIVASS: 4533 case MODASS: 4534 case ANDASS: 4535 case ORASS: 4536 case XORASS: 4537 case SHLASS: 4538 case SHRASS: 4539 case REAL: 4540 case IMAG: 4541 check_expr_side_effect(ln, szof); 4542 break; 4543 case ASSIGN: 4544 check_expr_assign(ln, szof); 4545 break; 4546 case CALL: 4547 check_expr_call(tn, ln, szof, vctx, cond, retval_discarded); 4548 break; 4549 case EQ: 4550 if (hflag && eqwarn) 4551 /* operator '==' found where '=' was expected */ 4552 warning(160); 4553 break; 4554 case CON: 4555 case NAME: 4556 case STRING: 4557 return false; 4558 default: 4559 break; 4560 } 4561 return true; 4562 } 4563 4564 /* 4565 * vctx ??? 4566 * cond whether the expression is a condition that 4567 * will be compared with 0 4568 * eqwarn whether the operator '==' might be a 4569 * misspelled '=' 4570 * fcall whether the expression is a function call 4571 * retval_discarded whether the return value of a function call 4572 * is discarded; such calls will be analyzed by 4573 * lint2 in messages 4, 8 and 9 4574 * szof whether the expression is part of a sizeof 4575 * expression, which means that its value is 4576 * discarded since only the type is relevant 4577 */ 4578 void 4579 check_expr_misc(const tnode_t *tn, bool vctx, bool cond, 4580 bool eqwarn, bool fcall, bool retval_discarded, bool szof) 4581 { 4582 tnode_t *ln, *rn; 4583 const mod_t *mp; 4584 op_t op; 4585 bool cvctx, ccond, eq, discard; 4586 4587 if (tn == NULL) 4588 return; 4589 4590 ln = tn->tn_left; 4591 rn = tn->tn_right; 4592 mp = &modtab[op = tn->tn_op]; 4593 4594 if (!check_expr_op(tn, op, ln, 4595 szof, fcall, vctx, cond, retval_discarded, eqwarn)) 4596 return; 4597 4598 cvctx = mp->m_value_context; 4599 ccond = mp->m_compares_with_zero; 4600 eq = mp->m_warn_if_operand_eq && 4601 !ln->tn_parenthesized && 4602 rn != NULL && !rn->tn_parenthesized; 4603 4604 /* 4605 * values of operands of ':' are not used if the type of at least 4606 * one of the operands (for gcc compatibility) is void 4607 * XXX test/value context of QUEST should probably be used as 4608 * context for both operands of COLON 4609 */ 4610 if (op == COLON && tn->tn_type->t_tspec == VOID) 4611 cvctx = ccond = false; 4612 discard = op == CVT && tn->tn_type->t_tspec == VOID; 4613 check_expr_misc(ln, cvctx, ccond, eq, op == CALL, discard, szof); 4614 4615 switch (op) { 4616 case PUSH: 4617 if (rn != NULL) 4618 check_expr_misc(rn, false, false, eq, false, false, 4619 szof); 4620 break; 4621 case LOGAND: 4622 case LOGOR: 4623 check_expr_misc(rn, false, true, eq, false, false, szof); 4624 break; 4625 case COLON: 4626 check_expr_misc(rn, cvctx, ccond, eq, false, false, szof); 4627 break; 4628 case COMMA: 4629 check_expr_misc(rn, vctx, cond, false, false, false, szof); 4630 break; 4631 default: 4632 if (mp->m_binary) 4633 check_expr_misc(rn, true, false, eq, false, false, 4634 szof); 4635 break; 4636 } 4637 } 4638 4639 /* 4640 * Return whether the expression can be used for static initialization. 4641 * 4642 * Constant initialization expressions must be constant or an address 4643 * of a static object with an optional offset. In the first case, 4644 * the result is returned in *offsp. In the second case, the static 4645 * object is returned in *symp and the offset in *offsp. 4646 * 4647 * The expression can consist of PLUS, MINUS, ADDR, NAME, STRING and 4648 * CON. Type conversions are allowed if they do not change binary 4649 * representation (including width). 4650 * 4651 * C99 6.6 "Constant expressions" 4652 * C99 6.7.8p4 restricts initializers for static storage duration 4653 */ 4654 bool 4655 constant_addr(const tnode_t *tn, const sym_t **symp, ptrdiff_t *offsp) 4656 { 4657 const sym_t *sym; 4658 ptrdiff_t offs1, offs2; 4659 tspec_t t, ot; 4660 4661 switch (tn->tn_op) { 4662 case MINUS: 4663 if (tn->tn_right->tn_op == CVT) 4664 return constant_addr(tn->tn_right, symp, offsp); 4665 else if (tn->tn_right->tn_op != CON) 4666 return false; 4667 /* FALLTHROUGH */ 4668 case PLUS: 4669 offs1 = offs2 = 0; 4670 if (tn->tn_left->tn_op == CON) { 4671 offs1 = (ptrdiff_t)tn->tn_left->tn_val->v_quad; 4672 if (!constant_addr(tn->tn_right, &sym, &offs2)) 4673 return false; 4674 } else if (tn->tn_right->tn_op == CON) { 4675 offs2 = (ptrdiff_t)tn->tn_right->tn_val->v_quad; 4676 if (tn->tn_op == MINUS) 4677 offs2 = -offs2; 4678 if (!constant_addr(tn->tn_left, &sym, &offs1)) 4679 return false; 4680 } else { 4681 return false; 4682 } 4683 *symp = sym; 4684 *offsp = offs1 + offs2; 4685 return true; 4686 case ADDR: 4687 if (tn->tn_left->tn_op == NAME) { 4688 *symp = tn->tn_left->tn_sym; 4689 *offsp = 0; 4690 return true; 4691 } else { 4692 /* 4693 * If this would be the front end of a compiler we 4694 * would return a label instead of 0, at least if 4695 * 'tn->tn_left->tn_op == STRING'. 4696 */ 4697 *symp = NULL; 4698 *offsp = 0; 4699 return true; 4700 } 4701 case CVT: 4702 t = tn->tn_type->t_tspec; 4703 ot = tn->tn_left->tn_type->t_tspec; 4704 if ((!is_integer(t) && t != PTR) || 4705 (!is_integer(ot) && ot != PTR)) { 4706 return false; 4707 } 4708 #if 0 4709 /* 4710 * consider: 4711 * struct foo { 4712 * unsigned char a; 4713 * } f = { 4714 * (unsigned char)(unsigned long) 4715 * (&(((struct foo *)0)->a)) 4716 * }; 4717 * since psize(unsigned long) != psize(unsigned char), 4718 * this fails. 4719 */ 4720 else if (psize(t) != psize(ot)) 4721 return -1; 4722 #endif 4723 return constant_addr(tn->tn_left, symp, offsp); 4724 default: 4725 return false; 4726 } 4727 } 4728 4729 /* Append s2 to s1, then free s2. */ 4730 strg_t * 4731 cat_strings(strg_t *s1, strg_t *s2) 4732 { 4733 4734 if (s1->st_char != s2->st_char) { 4735 /* cannot concatenate wide and regular string literals */ 4736 error(292); 4737 return s1; 4738 } 4739 4740 size_t len1 = s1->st_len; 4741 size_t len2 = s2->st_len; 4742 size_t chsize = s1->st_char ? sizeof(char) : sizeof(wchar_t); 4743 size_t size1 = len1 * chsize; 4744 size_t size2 = (len2 + 1) * chsize; 4745 s1->st_mem = xrealloc(s1->st_mem, size1 + size2); 4746 memcpy((char *)s1->st_mem + size1, s2->st_mem, size2); 4747 free(s2->st_mem); 4748 4749 s1->st_len = len1 + len2; 4750 free(s2); 4751 4752 return s1; 4753 } 4754 4755 4756 typedef struct stmt_expr { 4757 memory_pool se_mem; 4758 sym_t *se_sym; 4759 struct stmt_expr *se_enclosing; 4760 } stmt_expr; 4761 4762 static stmt_expr *stmt_exprs; 4763 4764 void 4765 begin_statement_expr(void) 4766 { 4767 stmt_expr *se = xmalloc(sizeof(*se)); 4768 se->se_mem = expr_save_memory(); 4769 se->se_sym = NULL; 4770 se->se_enclosing = stmt_exprs; 4771 stmt_exprs = se; 4772 } 4773 4774 void 4775 do_statement_expr(tnode_t *tn) 4776 { 4777 block_level--; 4778 mem_block_level--; 4779 stmt_exprs->se_sym = tn != NULL 4780 ? mktempsym(block_dup_type(tn->tn_type)) 4781 : NULL; /* after a syntax error */ 4782 mem_block_level++; 4783 block_level++; 4784 /* ({ }) is a GCC extension */ 4785 gnuism(320); 4786 } 4787 4788 tnode_t * 4789 end_statement_expr(void) 4790 { 4791 stmt_expr *se = stmt_exprs; 4792 if (se->se_sym == NULL) 4793 return NULL; /* after a syntax error */ 4794 tnode_t *tn = build_name(se->se_sym, false); 4795 (void)expr_save_memory(); /* leak */ 4796 expr_restore_memory(se->se_mem); 4797 stmt_exprs = se->se_enclosing; 4798 free(se); 4799 return tn; 4800 } 4801
Indexes created Tue Sep 23 01:09:51 GMT 2025