tree.c revision 1.674
1 /* $NetBSD: tree.c,v 1.674 2025/02/27 06:23:07 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 1.674 2025/02/27 06:23:07 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 bclr; /* bits that are definitely clear */ 59 } integer_constraints; 60 61 62 static int64_t 63 s64_min(int64_t a, int64_t b) 64 { 65 return a < b ? a : b; 66 } 67 68 static int64_t 69 s64_max(int64_t a, int64_t b) 70 { 71 return a > b ? a : b; 72 } 73 74 static uint64_t 75 s64_abs(int64_t x) 76 { 77 return x >= 0 ? (uint64_t)x : -(uint64_t)x; 78 } 79 80 static int64_t 81 s64_shr(int64_t x, unsigned amount) 82 { 83 return x >= 0 84 ? (int64_t)((uint64_t)x >> amount) 85 : (int64_t)~(~(uint64_t)x >> amount); 86 } 87 88 static uint64_t 89 u64_min(uint64_t a, uint64_t b) 90 { 91 return a < b ? a : b; 92 } 93 94 static uint64_t 95 u64_max(uint64_t a, uint64_t b) 96 { 97 return a > b ? a : b; 98 } 99 100 static uint64_t 101 u64_fill_right(uint64_t x) 102 { 103 x |= x >> 1; 104 x |= x >> 2; 105 x |= x >> 4; 106 x |= x >> 8; 107 x |= x >> 16; 108 x |= x >> 32; 109 return x; 110 } 111 112 static int 113 portable_rank_cmp(tspec_t t1, tspec_t t2) 114 { 115 const ttab_t *p1 = type_properties(t1), *p2 = type_properties(t2); 116 lint_assert(p1->tt_rank_kind == p2->tt_rank_kind); 117 lint_assert(p1->tt_rank_value > 0); 118 lint_assert(p2->tt_rank_value > 0); 119 return (int)p1->tt_rank_value - (int)p2->tt_rank_value; 120 } 121 122 static unsigned 123 width_in_bits(const type_t *tp) 124 { 125 lint_assert(is_integer(tp->t_tspec)); 126 return tp->t_bitfield 127 ? tp->t_bit_field_width 128 : size_in_bits(tp->t_tspec); 129 } 130 131 static uint64_t 132 ui_max_value(const type_t *tp) 133 { 134 return value_bits(width_in_bits(tp)); 135 } 136 137 static int64_t 138 si_max_value(const type_t *tp) 139 { 140 return (int64_t)(ui_max_value(tp) >> 1); 141 } 142 143 static int64_t 144 si_min_value(const type_t *tp) 145 { 146 return -si_max_value(tp) - 1; 147 } 148 149 static int64_t 150 si_mult_sat(const type_t *tp, int64_t l, int64_t r) 151 { 152 uint64_t al = s64_abs(l); 153 uint64_t ar = s64_abs(r); 154 bool neg = (l >= 0) != (r >= 0); 155 uint64_t max = ui_max_value(tp); 156 uint64_t max_prod = (uint64_t)max + (neg ? 1 : 0); 157 if (al == 0 || ar <= max_prod / al) 158 return l * r; 159 else if (neg) 160 return -1 - (int64_t)(max >> 1); 161 else 162 return (int64_t)(max >> 1); 163 } 164 165 static int64_t 166 si_plus_sat(const type_t *tp, int64_t a, int64_t b) 167 { 168 if (b >= 0) { 169 int64_t max = si_max_value(tp); 170 return a <= max - b ? a + b : max; 171 } else { 172 int64_t min = si_min_value(tp); 173 return a >= min - b ? a + b : min; 174 } 175 } 176 177 static int64_t 178 si_minus_sat(const type_t *tp, int64_t a, int64_t b) 179 { 180 if (b >= 0) { 181 int64_t min = si_min_value(tp); 182 return a >= min + b ? a - b : min; 183 } else { 184 int64_t max = si_max_value(tp); 185 return a <= max + b ? a - b : max; 186 } 187 } 188 189 static bool 190 ic_maybe_signed(const type_t *tp, integer_constraints ic) 191 { 192 return !is_uinteger(tp->t_tspec) && ic.bclr >> 63 == 0; 193 } 194 195 static bool 196 ic_maybe_signed_binary(const type_t *tp, 197 integer_constraints a, integer_constraints b) 198 { 199 return !is_uinteger(tp->t_tspec) && (a.bclr & b.bclr) >> 63 == 0; 200 } 201 202 static integer_constraints 203 ic_any(const type_t *tp) 204 { 205 integer_constraints c; 206 207 unsigned width = width_in_bits(tp); 208 uint64_t vbits = value_bits(width); 209 if (is_uinteger(tp->t_tspec)) { 210 c.smin = width < 64 ? 0 : INT64_MIN; 211 c.smax = width < 64 ? (int64_t)vbits : INT64_MAX; 212 c.umin = 0; 213 c.umax = vbits; 214 c.bclr = ~c.umax; 215 } else { 216 c.smin = -1 - (int64_t)(vbits >> 1); 217 c.smax = (int64_t)(vbits >> 1); 218 c.umin = 0; 219 c.umax = UINT64_MAX; 220 c.bclr = 0; 221 } 222 return c; 223 } 224 225 static integer_constraints 226 ic_mult(const type_t *tp, integer_constraints a, integer_constraints b) 227 { 228 integer_constraints c; 229 230 if (ic_maybe_signed_binary(tp, a, b)) { 231 int64_t ll = si_mult_sat(tp, a.smin, b.smin); 232 int64_t lu = si_mult_sat(tp, a.smin, b.smax); 233 int64_t ul = si_mult_sat(tp, a.smax, b.smin); 234 int64_t uu = si_mult_sat(tp, a.smax, b.smax); 235 236 c.smin = s64_min(ll, s64_min(lu, s64_min(ul, uu))); 237 c.smax = s64_max(ll, s64_max(lu, s64_max(ul, uu))); 238 c.umin = c.smin >= 0 ? (uint64_t)c.smin : 0; 239 c.umax = c.smin >= 0 ? (uint64_t)c.smax : UINT64_MAX; 240 c.bclr = ~u64_fill_right(c.umax); 241 return c; 242 } 243 244 if (a.umax > 0 && b.umax > ic_any(tp).umax / a.umax) 245 return ic_any(tp); 246 247 c.smin = INT64_MIN; 248 c.smax = INT64_MAX; 249 c.umin = a.umin * b.umin; 250 c.umax = a.umax * b.umax; 251 c.bclr = ~u64_fill_right(c.umax); 252 return c; 253 } 254 255 static integer_constraints 256 ic_div(const type_t *tp, integer_constraints a, integer_constraints b) 257 { 258 if (ic_maybe_signed_binary(tp, a, b)) { 259 if (b.smin >= 0) 260 return a; 261 return ic_any(tp); 262 } 263 264 integer_constraints c; 265 c.smin = INT64_MIN; 266 c.smax = INT64_MAX; 267 c.umin = a.umin / u64_max(b.umax, 1); 268 c.umax = a.umax / u64_max(b.umin, 1); 269 c.bclr = ~u64_fill_right(c.umax); 270 return c; 271 } 272 273 static integer_constraints 274 ic_mod(const type_t *tp, integer_constraints a, integer_constraints b) 275 { 276 if (ic_maybe_signed_binary(tp, a, b)) { 277 uint64_t max_abs_b = u64_max(s64_abs(b.smin), s64_abs(b.smax)); 278 if (max_abs_b >> 63 != 0 || max_abs_b == 0) 279 return a; 280 281 integer_constraints c; 282 c.smin = s64_max(a.smin, -(int64_t)(max_abs_b - 1)); 283 c.smax = s64_min(a.smax, (int64_t)(max_abs_b - 1)); 284 c.umin = 0; 285 c.umax = UINT64_MAX; 286 c.bclr = 0; 287 return c; 288 } 289 290 integer_constraints c; 291 c.smin = INT64_MIN; 292 c.smax = INT64_MAX; 293 c.umin = 0; 294 c.umax = b.umax - 1; 295 c.bclr = ~u64_fill_right(c.umax); 296 return c; 297 } 298 299 static integer_constraints 300 ic_plus(const type_t *tp, integer_constraints a, integer_constraints b) 301 { 302 if (ic_maybe_signed_binary(tp, a, b)) { 303 integer_constraints c; 304 c.smin = si_plus_sat(tp, a.smin, b.smin); 305 c.smax = si_plus_sat(tp, a.smax, b.smax); 306 c.umin = c.smin >= 0 ? (uint64_t)c.smin : 0; 307 c.umax = c.smin >= 0 ? (uint64_t)c.smax : UINT64_MAX; 308 c.bclr = 0; 309 return c; 310 } 311 312 uint64_t max = ui_max_value(tp); 313 integer_constraints c; 314 c.smin = INT64_MIN; 315 c.smax = INT64_MAX; 316 if (b.umax <= max - a.umax) { 317 c.umin = a.umin + b.umin; 318 c.umax = a.umax + b.umax; 319 } else { 320 c.umin = 0; 321 c.umax = max; 322 } 323 if (c.umax >> 63 == 0) { 324 c.smin = 0; 325 c.smax = (int64_t)c.umax; 326 } 327 c.bclr = ~u64_fill_right(c.umax); 328 return c; 329 } 330 331 static integer_constraints 332 ic_minus(const type_t *tp, integer_constraints a, integer_constraints b) 333 { 334 integer_constraints c; 335 c.smin = si_minus_sat(tp, a.smin, b.smax); 336 c.smax = si_minus_sat(tp, a.smax, b.smin); 337 338 if (ic_maybe_signed_binary(tp, a, b)) { 339 c.umin = c.smin >= 0 ? (uint64_t)c.smin : 0; 340 c.umax = c.smin >= 0 ? (uint64_t)c.smax : UINT64_MAX; 341 } else if (a.umin >= b.umax) { 342 c.umin = a.umin - b.umax; 343 c.umax = a.umax - b.umin; 344 } else { 345 c.umin = 0; 346 c.umax = is_uinteger(tp->t_tspec) ? ui_max_value(tp) 347 : UINT64_MAX; 348 } 349 c.bclr = ~u64_fill_right(c.umax); 350 return c; 351 } 352 353 static integer_constraints 354 ic_shl(const type_t *tp, integer_constraints a, integer_constraints b) 355 { 356 if (ic_maybe_signed(tp, a)) 357 return ic_any(tp); 358 359 unsigned amount; 360 if (b.smin == b.smax && b.smin >= 0 && b.smin < 64) 361 amount = (unsigned)b.smin; 362 else if (b.umin == b.umax && b.umin < 64) 363 amount = (unsigned)b.umin; 364 else 365 return ic_any(tp); 366 367 integer_constraints c; 368 c.umin = a.umin << amount; 369 c.umax = a.umax << amount; 370 if (c.umax >> (width_in_bits(tp) - 1) == 0) { 371 c.smin = (int64_t)c.umin; 372 c.smax = (int64_t)c.umax; 373 } else { 374 c.smin = INT64_MIN; 375 c.smax = INT64_MAX; 376 } 377 c.bclr = a.bclr << amount | (((uint64_t)1 << amount) - 1); 378 return c; 379 } 380 381 static integer_constraints 382 ic_shr(const type_t *tp, integer_constraints a, integer_constraints b) 383 { 384 if (ic_maybe_signed(tp, a)) 385 return ic_any(tp); 386 387 unsigned amount; 388 if (b.smin == b.smax && b.smin >= 0 && b.smin < 64) 389 amount = (unsigned)b.smin; 390 else if (b.umin == b.umax && b.umin < 64) 391 amount = (unsigned)b.umin; 392 else 393 return ic_any(tp); 394 395 integer_constraints c; 396 c.smin = s64_shr(a.smin, amount); 397 c.smax = s64_shr(a.smax, amount); 398 c.umin = a.umin >> amount; 399 c.umax = a.umax >> amount; 400 c.bclr = a.bclr >> amount | ~(~(uint64_t)0 >> amount); 401 return c; 402 } 403 404 static integer_constraints 405 ic_bitand(integer_constraints a, integer_constraints b) 406 { 407 integer_constraints c; 408 c.smin = a.smin & b.smin; 409 c.smax = a.smax & b.smax; 410 c.umin = a.umin & b.umin; 411 c.umax = a.umax & b.umax; 412 c.bclr = a.bclr | b.bclr; 413 return c; 414 } 415 416 static integer_constraints 417 ic_bitxor(const type_t *tp, integer_constraints a, integer_constraints b) 418 { 419 if (ic_maybe_signed_binary(tp, a, b)) 420 return ic_any(tp); 421 422 integer_constraints c; 423 c.smin = a.smin & b.smin; 424 c.smax = a.smax | b.smax; 425 c.umin = a.umin & b.umin; 426 c.umax = a.umax | b.umax; 427 c.bclr = a.bclr & b.bclr; 428 return c; 429 } 430 431 static integer_constraints 432 ic_bitor(integer_constraints a, integer_constraints b) 433 { 434 integer_constraints c; 435 c.smin = a.smin | b.smin; 436 c.smax = a.smax | b.smax; 437 c.umin = a.umin | b.umin; 438 c.umax = a.umax | b.umax; 439 c.bclr = a.bclr & b.bclr; 440 return c; 441 } 442 443 static integer_constraints 444 ic_quest_colon(integer_constraints a, integer_constraints b) 445 { 446 integer_constraints c; 447 c.smin = s64_min(a.smin, b.smin); 448 c.smax = s64_max(a.smax, b.smax); 449 c.umin = u64_min(a.umin, b.umin); 450 c.umax = u64_max(a.umax, b.umax); 451 c.bclr = a.bclr & b.bclr; 452 return c; 453 } 454 455 static integer_constraints 456 ic_con(const type_t *tp, const val_t *v) 457 { 458 lint_assert(is_integer(tp->t_tspec)); 459 int64_t si = v->u.integer; 460 uint64_t ui = (uint64_t)si; 461 462 integer_constraints c; 463 c.smin = si; 464 c.smax = si; 465 c.umin = ui; 466 c.umax = ui; 467 c.bclr = ~ui; 468 return c; 469 } 470 471 static integer_constraints 472 ic_cvt(const type_t *ntp, const type_t *otp, integer_constraints a) 473 { 474 unsigned new_width = width_in_bits(ntp); 475 unsigned old_width = width_in_bits(otp); 476 bool new_unsigned = is_uinteger(ntp->t_tspec); 477 bool old_unsigned = is_uinteger(otp->t_tspec); 478 479 if (new_width >= old_width && new_unsigned == old_unsigned) 480 return a; 481 if (new_width > old_width && old_unsigned) 482 return a; 483 if (new_unsigned && (~value_bits(new_width) & ~a.bclr) == 0) 484 return a; 485 return ic_any(ntp); 486 } 487 488 static integer_constraints 489 ic_expr(const tnode_t *tn) 490 { 491 integer_constraints lc, rc; 492 493 lint_assert(is_integer(tn->tn_type->t_tspec)); 494 495 switch (tn->tn_op) { 496 case MULT: 497 lc = ic_expr(tn->u.ops.left); 498 rc = ic_expr(tn->u.ops.right); 499 return ic_mult(tn->tn_type, lc, rc); 500 case DIV: 501 lc = ic_expr(tn->u.ops.left); 502 rc = ic_expr(tn->u.ops.right); 503 return ic_div(tn->tn_type, lc, rc); 504 case MOD: 505 lc = ic_expr(tn->u.ops.left); 506 rc = ic_expr(tn->u.ops.right); 507 return ic_mod(tn->tn_type, lc, rc); 508 case PLUS: 509 lc = ic_expr(tn->u.ops.left); 510 rc = ic_expr(tn->u.ops.right); 511 return ic_plus(tn->tn_type, lc, rc); 512 case MINUS: 513 if (tn->u.ops.left->tn_type->t_tspec == PTR) 514 return ic_any(tn->tn_type); 515 lc = ic_expr(tn->u.ops.left); 516 rc = ic_expr(tn->u.ops.right); 517 return ic_minus(tn->tn_type, lc, rc); 518 case SHL: 519 lc = ic_expr(tn->u.ops.left); 520 rc = ic_expr(tn->u.ops.right); 521 return ic_shl(tn->tn_type, lc, rc); 522 case SHR: 523 lc = ic_expr(tn->u.ops.left); 524 rc = ic_expr(tn->u.ops.right); 525 return ic_shr(tn->tn_type, lc, rc); 526 case BITAND: 527 lc = ic_expr(tn->u.ops.left); 528 rc = ic_expr(tn->u.ops.right); 529 return ic_bitand(lc, rc); 530 case BITXOR: 531 lc = ic_expr(tn->u.ops.left); 532 rc = ic_expr(tn->u.ops.right); 533 return ic_bitxor(tn->tn_type, lc, rc); 534 case BITOR: 535 lc = ic_expr(tn->u.ops.left); 536 rc = ic_expr(tn->u.ops.right); 537 return ic_bitor(lc, rc); 538 case QUEST: 539 lc = ic_expr(tn->u.ops.right->u.ops.left); 540 rc = ic_expr(tn->u.ops.right->u.ops.right); 541 return ic_quest_colon(lc, rc); 542 case CON: 543 return ic_con(tn->tn_type, &tn->u.value); 544 case CVT: 545 if (!is_integer(tn->u.ops.left->tn_type->t_tspec)) 546 return ic_any(tn->tn_type); 547 lc = ic_expr(tn->u.ops.left); 548 return ic_cvt(tn->tn_type, tn->u.ops.left->tn_type, lc); 549 default: 550 return ic_any(tn->tn_type); 551 } 552 } 553 554 uint64_t 555 possible_bits(const tnode_t *tn) 556 { 557 return ~ic_expr(tn).bclr; 558 } 559 560 bool 561 attributes_contain(const attribute_list *attrs, const char *str) 562 { 563 for (size_t i = 0, n = attrs->len; i < n; i++) { 564 const attribute *attr = attrs->attrs + i; 565 if (attr->prefix == NULL && strcmp(attr->name, str) == 0) 566 return true; 567 } 568 return false; 569 } 570 571 /* Build 'pointer to tp', 'array of tp' or 'function returning tp'. */ 572 type_t * 573 block_derive_type(type_t *tp, tspec_t t) 574 { 575 576 type_t *tp2 = block_zero_alloc(sizeof(*tp2), "type"); 577 tp2->t_tspec = t; 578 tp2->t_subt = tp; 579 return tp2; 580 } 581 582 /* 583 * Derive 'pointer to tp' or 'function returning tp'. 584 * The memory is freed at the end of the current expression. 585 */ 586 type_t * 587 expr_derive_type(type_t *tp, tspec_t t) 588 { 589 590 type_t *tp2 = expr_zero_alloc(sizeof(*tp2), "type"); 591 tp2->t_tspec = t; 592 tp2->t_subt = tp; 593 return tp2; 594 } 595 596 /* Create an expression from a unary or binary operator and its operands. */ 597 static tnode_t * 598 build_op(op_t op, bool sys, type_t *type, tnode_t *ln, tnode_t *rn) 599 { 600 601 tnode_t *ntn = expr_alloc_tnode(); 602 ntn->tn_op = op; 603 ntn->tn_type = type; 604 ntn->tn_sys = sys; 605 ntn->u.ops.left = ln; 606 ntn->u.ops.right = rn; 607 608 if (op == INDIR || op == FSEL) { 609 lint_assert(ln->tn_type->t_tspec == PTR); 610 tspec_t t = ln->tn_type->t_subt->t_tspec; 611 ntn->tn_lvalue = t != FUNC && t != VOID; 612 } 613 614 return ntn; 615 } 616 617 tnode_t * 618 build_constant(type_t *tp, val_t *v) 619 { 620 621 tnode_t *n = expr_alloc_tnode(); 622 n->tn_op = CON; 623 n->tn_type = tp; 624 n->u.value = *v; 625 n->u.value.v_tspec = tp->t_tspec; 626 free(v); 627 return n; 628 } 629 630 static tnode_t * 631 build_integer_constant(tspec_t t, int64_t si) 632 { 633 634 tnode_t *n = expr_alloc_tnode(); 635 n->tn_op = CON; 636 n->tn_type = gettyp(t); 637 n->u.value.v_tspec = t; 638 n->u.value.v_unsigned_since_c90 = false; 639 n->u.value.v_char_constant = false; 640 n->u.value.u.integer = si; 641 return n; 642 } 643 644 static void 645 fallback_symbol(sym_t *sym) 646 { 647 648 if (Tflag && fallback_symbol_strict_bool(sym)) 649 return; 650 651 if (funcsym != NULL && (strcmp(sym->s_name, "__FUNCTION__") == 0 || 652 strcmp(sym->s_name, "__PRETTY_FUNCTION__") == 0)) { 653 /* __FUNCTION__/__PRETTY_FUNCTION__ is a GCC extension */ 654 gnuism(316); 655 goto return_function_name; 656 } 657 658 if (funcsym != NULL && strcmp(sym->s_name, "__func__") == 0) { 659 if (!allow_c99) 660 /* __func__ is a C99 feature */ 661 warning(317); 662 /* C11 6.4.2.2 */ 663 return_function_name: 664 sym->s_type = block_derive_type(gettyp(CHAR), ARRAY); 665 sym->s_type->t_const = true; 666 sym->s_type->u.dimension = (int)strlen(funcsym->s_name) + 1; 667 return; 668 } 669 670 /* '%s' undefined */ 671 error(99, sym->s_name); 672 } 673 674 /* 675 * Functions that are predeclared by GCC or other compilers can be called 676 * with arbitrary arguments. Since lint usually runs after a successful 677 * compilation, it's the compiler's job to catch any errors. 678 */ 679 bool 680 is_compiler_builtin(const char *name) 681 { 682 /* https://gcc.gnu.org/onlinedocs/gcc/C-Extensions.html */ 683 if (allow_gcc) { 684 if (strncmp(name, "__atomic_", 9) == 0 || 685 strncmp(name, "__builtin_", 10) == 0 || 686 strcmp(name, "alloca") == 0 || 687 /* obsolete but still in use, as of 2021 */ 688 strncmp(name, "__sync_", 7) == 0) 689 return true; 690 } 691 692 /* https://software.intel.com/sites/landingpage/IntrinsicsGuide/ */ 693 if (strncmp(name, "_mm_", 4) == 0) 694 return true; 695 696 return false; 697 } 698 699 static bool 700 str_ends_with(const char *haystack, const char *needle) 701 { 702 size_t hlen = strlen(haystack); 703 size_t nlen = strlen(needle); 704 705 return nlen <= hlen && 706 memcmp(haystack + hlen - nlen, needle, nlen) == 0; 707 } 708 709 /* https://gcc.gnu.org/onlinedocs/gcc/Integer-Overflow-Builtins.html */ 710 static bool 711 is_gcc_bool_builtin(const char *name) 712 { 713 return strncmp(name, "__builtin_", 10) == 0 && 714 (str_ends_with(name, "_overflow") || 715 str_ends_with(name, "_overflow_p")); 716 } 717 718 static void 719 build_name_call(sym_t *sym) 720 { 721 722 if (is_compiler_builtin(sym->s_name)) { 723 /* 724 * Do not warn about these, just assume that they are regular 725 * functions compatible with non-prototype calling conventions. 726 */ 727 if (allow_gcc && is_gcc_bool_builtin(sym->s_name)) 728 sym->s_type = gettyp(BOOL); 729 } else if (allow_c99) 730 /* function '%s' implicitly declared to return int */ 731 error(215, sym->s_name); 732 else if (!allow_trad) 733 /* function '%s' implicitly declared to return int */ 734 warning(215, sym->s_name); 735 736 /* XXX if !allow_c90, the symbol should be exported to level 0 */ 737 sym->s_type = block_derive_type(sym->s_type, FUNC); 738 } 739 740 /* Create a node for a name (symbol table entry). */ 741 tnode_t * 742 build_name(sym_t *sym, bool is_funcname) 743 { 744 745 if (sym->s_scl == NO_SCL && !in_gcc_attribute) { 746 sym->s_scl = EXTERN; 747 sym->s_def = DECL; 748 if (is_funcname) 749 build_name_call(sym); 750 else 751 fallback_symbol(sym); 752 } 753 754 lint_assert(sym->s_kind == SK_VCFT || sym->s_kind == SK_MEMBER); 755 756 tnode_t *n = expr_alloc_tnode(); 757 n->tn_type = sym->s_type; 758 if (sym->s_scl == BOOL_CONST) { 759 n->tn_op = CON; 760 n->u.value.v_tspec = BOOL; 761 n->u.value.v_unsigned_since_c90 = false; 762 n->u.value.v_char_constant = false; 763 n->u.value.u.integer = sym->u.s_bool_constant ? 1 : 0; 764 } else if (sym->s_scl == ENUM_CONST) { 765 n->tn_op = CON; 766 n->u.value.v_tspec = INT; /* ENUM is in n->tn_type */ 767 n->u.value.v_unsigned_since_c90 = false; 768 n->u.value.v_char_constant = false; 769 n->u.value.u.integer = sym->u.s_enum_constant; 770 } else { 771 n->tn_op = NAME; 772 n->u.sym = sym; 773 if (sym->s_kind == SK_VCFT && sym->s_type->t_tspec != FUNC) 774 n->tn_lvalue = true; 775 } 776 777 return n; 778 } 779 780 tnode_t * 781 build_string(buffer *lit) 782 { 783 size_t value_len = lit->len; 784 if (lit->data != NULL) { 785 quoted_iterator it = { .end = 0 }; 786 for (value_len = 0; quoted_next(lit, &it); value_len++) 787 continue; 788 } 789 790 type_t *tp = expr_zero_alloc(sizeof(*tp), "type"); 791 tp->t_tspec = ARRAY; 792 tp->t_subt = gettyp(lit->data != NULL ? CHAR : WCHAR_TSPEC); 793 tp->u.dimension = (int)(value_len + 1); 794 795 tnode_t *n = expr_alloc_tnode(); 796 n->tn_op = STRING; 797 n->tn_type = tp; 798 n->tn_lvalue = true; 799 800 n->u.str_literals = expr_zero_alloc(sizeof(*n->u.str_literals), "tnode.string"); 801 n->u.str_literals->len = lit->len; 802 803 if (lit->data != NULL) { 804 n->u.str_literals->data = expr_zero_alloc(lit->len + 1, 805 "tnode.string.data"); 806 (void)memcpy(n->u.str_literals->data, lit->data, lit->len + 1); 807 free(lit->data); 808 } 809 free(lit); 810 811 return n; 812 } 813 814 tnode_t * 815 build_generic_selection(const tnode_t *expr, 816 struct generic_association *sel) 817 { 818 tnode_t *default_result = NULL; 819 820 for (; sel != NULL; sel = sel->ga_prev) { 821 if (expr != NULL && 822 types_compatible(sel->ga_arg, expr->tn_type, 823 false, false, NULL)) 824 return sel->ga_result; 825 else if (sel->ga_arg == NULL) 826 default_result = sel->ga_result; 827 } 828 return default_result; 829 } 830 831 static bool 832 is_out_of_char_range(const tnode_t *tn) 833 { 834 return tn->tn_op == CON && 835 !tn->u.value.v_char_constant && 836 !(0 <= tn->u.value.u.integer && 837 tn->u.value.u.integer < 1 << (CHAR_SIZE - 1)); 838 } 839 840 static bool 841 check_nonportable_char_comparison(op_t op, 842 const tnode_t *ln, tspec_t lt, 843 const tnode_t *rn, tspec_t rt) 844 { 845 if (!(hflag || pflag)) 846 return true; 847 848 if (lt == CHAR && is_out_of_char_range(rn)) { 849 char buf[128]; 850 (void)snprintf(buf, sizeof(buf), "%s %d", 851 op_name(op), (int)rn->u.value.u.integer); 852 /* nonportable character comparison '%s' */ 853 warning(230, buf); 854 return false; 855 } 856 if (rt == CHAR && is_out_of_char_range(ln)) { 857 char buf[128]; 858 (void)snprintf(buf, sizeof(buf), "%d %s ?", 859 (int)ln->u.value.u.integer, op_name(op)); 860 /* nonportable character comparison '%s' */ 861 warning(230, buf); 862 return false; 863 } 864 return true; 865 } 866 867 static void 868 check_integer_comparison(op_t op, tnode_t *ln, tnode_t *rn) 869 { 870 871 tspec_t lt = ln->tn_type->t_tspec; 872 tspec_t rt = rn->tn_type->t_tspec; 873 874 if (ln->tn_op != CON && rn->tn_op != CON) 875 return; 876 877 if (!is_integer(lt) || !is_integer(rt)) 878 return; 879 880 if (any_query_enabled && !in_system_header) { 881 if (lt == CHAR && rn->tn_op == CON && 882 !rn->u.value.v_char_constant) { 883 /* comparison '%s' of 'char' with plain integer %d */ 884 query_message(14, 885 op_name(op), (int)rn->u.value.u.integer); 886 } 887 if (rt == CHAR && ln->tn_op == CON && 888 !ln->u.value.v_char_constant) { 889 /* comparison '%s' of 'char' with plain integer %d */ 890 query_message(14, 891 op_name(op), (int)ln->u.value.u.integer); 892 } 893 } 894 895 if (!check_nonportable_char_comparison(op, ln, lt, rn, rt)) 896 return; 897 898 if (is_uinteger(lt) && !is_uinteger(rt) && 899 rn->tn_op == CON && rn->u.value.u.integer <= 0) { 900 if (rn->u.value.u.integer < 0) { 901 /* operator '%s' compares '%s' with '%s' */ 902 warning(162, op_name(op), 903 type_name(ln->tn_type), "negative constant"); 904 } else if (op == LT || op == GE) 905 /* operator '%s' compares '%s' with '%s' */ 906 warning(162, op_name(op), type_name(ln->tn_type), "0"); 907 return; 908 } 909 if (is_uinteger(rt) && !is_uinteger(lt) && 910 ln->tn_op == CON && ln->u.value.u.integer <= 0) { 911 if (ln->u.value.u.integer < 0) { 912 /* operator '%s' compares '%s' with '%s' */ 913 warning(162, op_name(op), 914 "negative constant", type_name(rn->tn_type)); 915 } else if (op == GT || op == LE) 916 /* operator '%s' compares '%s' with '%s' */ 917 warning(162, op_name(op), "0", type_name(rn->tn_type)); 918 return; 919 } 920 } 921 922 static const tspec_t arith_rank[] = { 923 LDOUBLE, DOUBLE, FLOAT, 924 #ifdef INT128_SIZE 925 UINT128, INT128, 926 #endif 927 ULLONG, LLONG, 928 ULONG, LONG, 929 UINT, INT, 930 }; 931 932 /* Keep unsigned in traditional C */ 933 static tspec_t 934 usual_arithmetic_conversion_trad(tspec_t lt, tspec_t rt) 935 { 936 937 size_t i; 938 for (i = 0; arith_rank[i] != INT; i++) 939 if (lt == arith_rank[i] || rt == arith_rank[i]) 940 break; 941 942 tspec_t t = arith_rank[i]; 943 if (is_uinteger(lt) || is_uinteger(rt)) 944 if (is_integer(t) && !is_uinteger(t)) 945 return unsigned_type(t); 946 return t; 947 } 948 949 static tspec_t 950 usual_arithmetic_conversion_c90(tspec_t lt, tspec_t rt) 951 { 952 953 if (lt == rt) 954 return lt; 955 956 if (lt == LCOMPLEX || rt == LCOMPLEX) 957 return LCOMPLEX; 958 if (lt == DCOMPLEX || rt == DCOMPLEX) 959 return DCOMPLEX; 960 if (lt == FCOMPLEX || rt == FCOMPLEX) 961 return FCOMPLEX; 962 if (lt == LDOUBLE || rt == LDOUBLE) 963 return LDOUBLE; 964 if (lt == DOUBLE || rt == DOUBLE) 965 return DOUBLE; 966 if (lt == FLOAT || rt == FLOAT) 967 return FLOAT; 968 969 if (size_in_bits(lt) > size_in_bits(rt)) 970 return lt; 971 if (size_in_bits(lt) < size_in_bits(rt)) 972 return rt; 973 974 size_t i; 975 for (i = 3; arith_rank[i] != INT; i++) 976 if (arith_rank[i] == lt || arith_rank[i] == rt) 977 break; 978 if ((is_uinteger(lt) || is_uinteger(rt)) && 979 !is_uinteger(arith_rank[i])) 980 i--; 981 return arith_rank[i]; 982 } 983 984 static tnode_t * 985 apply_usual_arithmetic_conversions(op_t op, tnode_t *tn, tspec_t t) 986 { 987 type_t *ntp = expr_dup_type(tn->tn_type); 988 ntp->t_tspec = t; 989 if (tn->tn_op != CON) { 990 /* usual arithmetic conversion for '%s' from '%s' to '%s' */ 991 query_message(4, op_name(op), 992 type_name(tn->tn_type), type_name(ntp)); 993 } 994 return convert(op, 0, ntp, tn); 995 } 996 997 /* 998 * Apply the "usual arithmetic conversions" (C99 6.3.1.8), which gives both 999 * operands the same type. 1000 */ 1001 static void 1002 balance(op_t op, tnode_t **lnp, tnode_t **rnp) 1003 { 1004 1005 tspec_t lt = (*lnp)->tn_type->t_tspec; 1006 tspec_t rt = (*rnp)->tn_type->t_tspec; 1007 if (!is_arithmetic(lt) || !is_arithmetic(rt)) 1008 return; 1009 1010 tspec_t t = allow_c90 1011 ? usual_arithmetic_conversion_c90(lt, rt) 1012 : usual_arithmetic_conversion_trad(lt, rt); 1013 1014 if (modtab[op].m_comparison 1015 && is_integer(lt) && (*lnp)->tn_op != CON 1016 && is_floating(t) && (*rnp)->tn_op == CON) 1017 /* comparing integer '%s' to floating point constant %Lg */ 1018 warning(379, type_name((*lnp)->tn_type), 1019 (*rnp)->u.value.u.floating); 1020 1021 if (t != lt) 1022 *lnp = apply_usual_arithmetic_conversions(op, *lnp, t); 1023 if (t != rt) 1024 *rnp = apply_usual_arithmetic_conversions(op, *rnp, t); 1025 1026 if (is_integer(t)) { 1027 unsigned lw = width_in_bits((*lnp)->tn_type); 1028 unsigned rw = width_in_bits((*rnp)->tn_type); 1029 if (lw < rw) 1030 *lnp = convert(NOOP, 0, (*rnp)->tn_type, *lnp); 1031 if (rw < lw) 1032 *rnp = convert(NOOP, 0, (*lnp)->tn_type, *rnp); 1033 } 1034 } 1035 1036 static tnode_t * 1037 build_address(bool sys, tnode_t *tn) 1038 { 1039 /* eliminate '&*' */ 1040 if (tn->tn_op == INDIR && 1041 tn->u.ops.left->tn_type->t_tspec == PTR && 1042 tn->u.ops.left->tn_type->t_subt == tn->tn_type) { 1043 return tn->u.ops.left; 1044 } 1045 1046 return build_op(ADDR, sys, expr_derive_type(tn->tn_type, PTR), 1047 tn, NULL); 1048 } 1049 1050 static uint64_t 1051 fold_unsigned_integer(op_t op, uint64_t l, uint64_t r, 1052 uint64_t max_value, bool *overflow) 1053 { 1054 switch (op) { 1055 case COMPL: 1056 return ~l & max_value; 1057 case UPLUS: 1058 return +l; 1059 case UMINUS: 1060 return -l & max_value; 1061 case MULT: 1062 *overflow = r > 0 && l > max_value / r; 1063 return l * r; 1064 case DIV: 1065 if (r == 0) { 1066 /* division by 0 */ 1067 error(139); 1068 return max_value; 1069 } 1070 return l / r; 1071 case MOD: 1072 if (r == 0) { 1073 /* modulus by 0 */ 1074 error(140); 1075 return 0; 1076 } 1077 return l % r; 1078 case PLUS: 1079 *overflow = l > max_value - r; 1080 return l + r; 1081 case MINUS: 1082 *overflow = l < r; 1083 return l - r; 1084 case SHL: 1085 /* TODO: warn about out-of-bounds 'r'. */ 1086 /* TODO: warn about overflow. */ 1087 return l << (r & 63); 1088 case SHR: 1089 /* TODO: warn about out-of-bounds 'r'. */ 1090 return l >> (r & 63); 1091 case LT: 1092 return l < r ? 1 : 0; 1093 case LE: 1094 return l <= r ? 1 : 0; 1095 case GT: 1096 return l > r ? 1 : 0; 1097 case GE: 1098 return l >= r ? 1 : 0; 1099 case EQ: 1100 return l == r ? 1 : 0; 1101 case NE: 1102 return l != r ? 1 : 0; 1103 case BITAND: 1104 return l & r; 1105 case BITXOR: 1106 return l ^ r; 1107 case BITOR: 1108 return l | r; 1109 default: 1110 lint_assert(/*CONSTCOND*/false); 1111 /* NOTREACHED */ 1112 } 1113 } 1114 1115 static int64_t 1116 fold_signed_integer(op_t op, int64_t l, int64_t r, 1117 int64_t min_value, int64_t max_value, bool *overflow) 1118 { 1119 switch (op) { 1120 case COMPL: 1121 return ~l; 1122 case UPLUS: 1123 return +l; 1124 case UMINUS: 1125 *overflow = l == min_value; 1126 return *overflow ? l : -l; 1127 case MULT:; 1128 uint64_t al = s64_abs(l); 1129 uint64_t ar = s64_abs(r); 1130 bool neg = (l >= 0) != (r >= 0); 1131 uint64_t max_prod = (uint64_t)max_value + (neg ? 1 : 0); 1132 if (al > 0 && ar > max_prod / al) { 1133 *overflow = true; 1134 return neg ? min_value : max_value; 1135 } 1136 return l * r; 1137 case DIV: 1138 if (r == 0) { 1139 /* division by 0 */ 1140 error(139); 1141 return max_value; 1142 } 1143 if (l == min_value && r == -1) { 1144 *overflow = true; 1145 return l; 1146 } 1147 return l / r; 1148 case MOD: 1149 if (r == 0) { 1150 /* modulus by 0 */ 1151 error(140); 1152 return 0; 1153 } 1154 if (l == min_value && r == -1) { 1155 *overflow = true; 1156 return 0; 1157 } 1158 return l % r; 1159 case PLUS: 1160 if (r > 0 && l > max_value - r) { 1161 *overflow = true; 1162 return max_value; 1163 } 1164 if (r < 0 && l < min_value - r) { 1165 *overflow = true; 1166 return min_value; 1167 } 1168 return l + r; 1169 case MINUS: 1170 if (r > 0 && l < min_value + r) { 1171 *overflow = true; 1172 return min_value; 1173 } 1174 if (r < 0 && l > max_value + r) { 1175 *overflow = true; 1176 return max_value; 1177 } 1178 return l - r; 1179 case SHL: 1180 /* TODO: warn about out-of-bounds 'r'. */ 1181 /* TODO: warn about overflow. */ 1182 return l << (r & 63); 1183 case SHR: 1184 /* TODO: warn about out-of-bounds 'r'. */ 1185 return s64_shr(l, r & 63); 1186 case LT: 1187 return l < r ? 1 : 0; 1188 case LE: 1189 return l <= r ? 1 : 0; 1190 case GT: 1191 return l > r ? 1 : 0; 1192 case GE: 1193 return l >= r ? 1 : 0; 1194 case EQ: 1195 return l == r ? 1 : 0; 1196 case NE: 1197 return l != r ? 1 : 0; 1198 case BITAND: 1199 return l & r; 1200 case BITXOR: 1201 return l ^ r; 1202 case BITOR: 1203 return l | r; 1204 default: 1205 lint_assert(/*CONSTCOND*/false); 1206 /* NOTREACHED */ 1207 } 1208 } 1209 1210 static tnode_t * 1211 fold_constant_integer(tnode_t *tn) 1212 { 1213 1214 lint_assert(has_operands(tn)); 1215 tspec_t t = tn->u.ops.left->tn_type->t_tspec; 1216 int64_t l = tn->u.ops.left->u.value.u.integer; 1217 int64_t r = is_binary(tn) ? tn->u.ops.right->u.value.u.integer : 0; 1218 uint64_t mask = value_bits(size_in_bits(t)); 1219 1220 int64_t res; 1221 bool overflow = false; 1222 if (!is_integer(t) || is_uinteger(t)) { 1223 uint64_t u_res = fold_unsigned_integer(tn->tn_op, 1224 (uint64_t)l, (uint64_t)r, mask, &overflow); 1225 if (u_res > mask) 1226 overflow = true; 1227 res = (int64_t)u_res; 1228 if (overflow && hflag) { 1229 char buf[128]; 1230 if (is_binary(tn)) { 1231 snprintf(buf, sizeof(buf), "%ju %s %ju", 1232 (uintmax_t)l, op_name(tn->tn_op), 1233 (uintmax_t)r); 1234 } else { 1235 snprintf(buf, sizeof(buf), "%s%ju", 1236 op_name(tn->tn_op), (uintmax_t)l); 1237 } 1238 /* '%s' overflows '%s' */ 1239 warning(141, buf, type_name(tn->tn_type)); 1240 } 1241 } else { 1242 int64_t max_value = (int64_t)(mask >> 1); 1243 int64_t min_value = -max_value - 1; 1244 res = fold_signed_integer(tn->tn_op, 1245 l, r, min_value, max_value, &overflow); 1246 if (res < min_value || res > max_value) 1247 overflow = true; 1248 if (overflow && hflag) { 1249 char buf[128]; 1250 if (is_binary(tn)) { 1251 snprintf(buf, sizeof(buf), "%jd %s %jd", 1252 (intmax_t)l, op_name(tn->tn_op), 1253 (intmax_t)r); 1254 } else if (tn->tn_op == UMINUS && l < 0) { 1255 snprintf(buf, sizeof(buf), "-(%jd)", 1256 (intmax_t)l); 1257 } else { 1258 snprintf(buf, sizeof(buf), "%s%jd", 1259 op_name(tn->tn_op), (intmax_t)l); 1260 } 1261 /* '%s' overflows '%s' */ 1262 warning(141, buf, type_name(tn->tn_type)); 1263 } 1264 } 1265 1266 val_t *v = xcalloc(1, sizeof(*v)); 1267 v->v_tspec = tn->tn_type->t_tspec; 1268 v->u.integer = convert_integer(res, t, size_in_bits(t)); 1269 1270 tnode_t *cn = build_constant(tn->tn_type, v); 1271 if (tn->u.ops.left->tn_system_dependent) 1272 cn->tn_system_dependent = true; 1273 if (is_binary(tn) && tn->u.ops.right->tn_system_dependent) 1274 cn->tn_system_dependent = true; 1275 1276 return cn; 1277 } 1278 1279 static tnode_t * 1280 build_struct_access(op_t op, bool sys, tnode_t *ln, tnode_t *rn) 1281 { 1282 1283 lint_assert(rn->tn_op == NAME); 1284 lint_assert(is_member(rn->u.sym)); 1285 1286 bool lvalue = op == ARROW || ln->tn_lvalue; 1287 1288 if (op == POINT) 1289 ln = build_address(sys, ln); 1290 else if (ln->tn_type->t_tspec != PTR) { 1291 lint_assert(!allow_c90); 1292 lint_assert(is_integer(ln->tn_type->t_tspec)); 1293 ln = convert(NOOP, 0, expr_derive_type(gettyp(VOID), PTR), ln); 1294 } 1295 1296 tnode_t *ctn = build_integer_constant(PTRDIFF_TSPEC, 1297 rn->u.sym->u.s_member.sm_offset_in_bits / CHAR_SIZE); 1298 1299 type_t *ptr_tp = expr_derive_type(rn->tn_type, PTR); 1300 tnode_t *ntn = build_op(PLUS, sys, ptr_tp, ln, ctn); 1301 if (ln->tn_op == CON) 1302 ntn = fold_constant_integer(ntn); 1303 1304 op_t nop = rn->tn_type->t_bitfield ? FSEL : INDIR; 1305 ntn = build_op(nop, sys, ntn->tn_type->t_subt, ntn, NULL); 1306 if (!lvalue) 1307 ntn->tn_lvalue = false; 1308 1309 return ntn; 1310 } 1311 1312 /* 1313 * Get the size in bytes of type tp->t_subt, as a constant expression of type 1314 * ptrdiff_t as seen from the target platform. 1315 */ 1316 static tnode_t * 1317 subt_size_in_bytes(type_t *tp) 1318 { 1319 1320 lint_assert(tp->t_tspec == PTR); 1321 tp = tp->t_subt; 1322 1323 int elem = 1; 1324 while (tp->t_tspec == ARRAY) { 1325 elem *= tp->u.dimension; 1326 tp = tp->t_subt; 1327 } 1328 1329 int elsz_in_bits = 0; 1330 switch (tp->t_tspec) { 1331 case FUNC: 1332 /* pointer to function is not allowed here */ 1333 error(110); 1334 break; 1335 case VOID: 1336 /* cannot do pointer arithmetic on operand of unknown size */ 1337 gnuism(136); 1338 break; 1339 case STRUCT: 1340 case UNION: 1341 if ((elsz_in_bits = (int)tp->u.sou->sou_size_in_bits) == 0) 1342 /* cannot do pointer arithmetic on operand of ... */ 1343 error(136); 1344 break; 1345 case ENUM: 1346 if (is_incomplete(tp)) 1347 /* cannot do pointer arithmetic on operand of ... */ 1348 warning(136); 1349 /* FALLTHROUGH */ 1350 default: 1351 if ((elsz_in_bits = size_in_bits(tp->t_tspec)) == 0) 1352 /* cannot do pointer arithmetic on operand of ... */ 1353 error(136); 1354 else 1355 lint_assert(elsz_in_bits != -1); 1356 break; 1357 } 1358 1359 if (elem == 0 && elsz_in_bits != 0) 1360 /* cannot do pointer arithmetic on operand of unknown size */ 1361 error(136); 1362 1363 if (elsz_in_bits == 0) 1364 elsz_in_bits = CHAR_SIZE; 1365 1366 return build_integer_constant(PTRDIFF_TSPEC, 1367 (int64_t)(elem * elsz_in_bits / CHAR_SIZE)); 1368 } 1369 1370 static tnode_t * 1371 build_prepost_incdec(op_t op, bool sys, tnode_t *ln) 1372 { 1373 1374 lint_assert(ln != NULL); 1375 tnode_t *cn = ln->tn_type->t_tspec == PTR 1376 ? subt_size_in_bytes(ln->tn_type) 1377 : build_integer_constant(INT, 1); 1378 return build_op(op, sys, ln->tn_type, ln, cn); 1379 } 1380 1381 static void 1382 check_enum_array_index(const tnode_t *ln, const tnode_t *rn) 1383 { 1384 1385 if (ln->tn_op != ADDR || ln->u.ops.left->tn_op != NAME) 1386 return; 1387 1388 const type_t *ltp = ln->u.ops.left->tn_type; 1389 if (ltp->t_tspec != ARRAY || ltp->t_incomplete_array) 1390 return; 1391 1392 if (rn->tn_op != CVT || !rn->tn_type->t_is_enum) 1393 return; 1394 if (rn->u.ops.left->tn_op != LOAD) 1395 return; 1396 1397 const type_t *rtp = rn->u.ops.left->tn_type; 1398 const sym_t *ec = rtp->u.enumer->en_first_enumerator; 1399 const sym_t *max_ec = ec; 1400 lint_assert(ec != NULL); 1401 for (ec = ec->s_next; ec != NULL; ec = ec->s_next) 1402 if (ec->u.s_enum_constant > max_ec->u.s_enum_constant) 1403 max_ec = ec; 1404 1405 int64_t max_enum_value = max_ec->u.s_enum_constant; 1406 lint_assert(INT_MIN <= max_enum_value && max_enum_value <= INT_MAX); 1407 1408 int max_array_index = ltp->u.dimension - 1; 1409 if (max_enum_value == max_array_index) 1410 return; 1411 1412 if (max_enum_value == max_array_index + 1 && 1413 (strstr(max_ec->s_name, "MAX") != NULL || 1414 strstr(max_ec->s_name, "max") != NULL || 1415 strstr(max_ec->s_name, "NUM") != NULL || 1416 strstr(max_ec->s_name, "num") != NULL || 1417 strncmp(max_ec->s_name, "N_", 2) == 0)) 1418 return; 1419 1420 /* maximum value %d for '%s' of type '%s' does not match maximum array index %d */ 1421 warning(348, (int)max_enum_value, max_ec->s_name, type_name(rtp), 1422 max_array_index); 1423 print_previous_declaration(max_ec); 1424 } 1425 1426 static tnode_t * 1427 build_plus_minus(op_t op, bool sys, tnode_t *ln, tnode_t *rn) 1428 { 1429 1430 if (rn->tn_type->t_tspec == PTR && is_integer(ln->tn_type->t_tspec)) { 1431 tnode_t *tmp = ln; 1432 ln = rn; 1433 rn = tmp; 1434 /* pointer addition has integer on the left-hand side */ 1435 query_message(5); 1436 } 1437 1438 /* pointer +- integer */ 1439 tspec_t lt = ln->tn_type->t_tspec; 1440 tspec_t rt = rn->tn_type->t_tspec; 1441 if (lt == PTR && rt != PTR) { 1442 lint_assert(is_integer(rt)); 1443 1444 check_ctype_macro_invocation(ln, rn); 1445 check_enum_array_index(ln, rn); 1446 1447 tnode_t *elsz = subt_size_in_bytes(ln->tn_type); 1448 tspec_t szt = elsz->tn_type->t_tspec; 1449 if (rt != szt && rt != unsigned_type(szt)) 1450 rn = convert(NOOP, 0, elsz->tn_type, rn); 1451 1452 tnode_t *prod = build_op(MULT, sys, rn->tn_type, rn, elsz); 1453 if (rn->tn_op == CON) 1454 prod = fold_constant_integer(prod); 1455 1456 return build_op(op, sys, ln->tn_type, ln, prod); 1457 } 1458 1459 /* pointer - pointer */ 1460 if (rt == PTR) { 1461 lint_assert(lt == PTR); 1462 lint_assert(op == MINUS); 1463 1464 type_t *ptrdiff = gettyp(PTRDIFF_TSPEC); 1465 tnode_t *raw_diff = build_op(op, sys, ptrdiff, ln, rn); 1466 if (ln->tn_op == CON && rn->tn_op == CON) 1467 raw_diff = fold_constant_integer(raw_diff); 1468 1469 tnode_t *elsz = subt_size_in_bytes(ln->tn_type); 1470 balance(NOOP, &raw_diff, &elsz); 1471 1472 return build_op(DIV, sys, ptrdiff, raw_diff, elsz); 1473 } 1474 1475 return build_op(op, sys, ln->tn_type, ln, rn); 1476 } 1477 1478 static tnode_t * 1479 build_bit_shift(op_t op, bool sys, tnode_t *ln, tnode_t *rn) 1480 { 1481 1482 if (!allow_c90 && rn->tn_type->t_tspec != INT) 1483 // XXX: C1978 7.5 says: "Both [operators] perform the usual 1484 // arithmetic conversions on their operands." 1485 // TODO: Add a test to exercise this part of the code. 1486 rn = convert(NOOP, 0, gettyp(INT), rn); 1487 return build_op(op, sys, ln->tn_type, ln, rn); 1488 } 1489 1490 static bool 1491 is_null_pointer(const tnode_t *tn) 1492 { 1493 tspec_t t = tn->tn_type->t_tspec; 1494 1495 // TODO: Investigate how other pointers are stored, in particular, 1496 // whether a pointer constant can have a non-zero value. 1497 // If not, simplify the code below. 1498 return ((t == PTR && tn->tn_type->t_subt->t_tspec == VOID) 1499 || is_integer(t)) 1500 && (tn->tn_op == CON && tn->u.value.u.integer == 0); 1501 } 1502 1503 /* Return a type based on tp1, with added qualifiers from tp2. */ 1504 static type_t * 1505 merge_qualifiers(type_t *tp1, const type_t *tp2) 1506 { 1507 1508 lint_assert(tp1->t_tspec == PTR); 1509 lint_assert(tp2->t_tspec == PTR); 1510 1511 bool c1 = tp1->t_subt->t_const; 1512 bool c2 = tp2->t_subt->t_const; 1513 bool v1 = tp1->t_subt->t_volatile; 1514 bool v2 = tp2->t_subt->t_volatile; 1515 1516 if (c1 == (c1 | c2) && v1 == (v1 | v2)) 1517 return tp1; 1518 1519 type_t *nstp = expr_dup_type(tp1->t_subt); 1520 nstp->t_const |= c2; 1521 nstp->t_volatile |= v2; 1522 1523 type_t *ntp = expr_dup_type(tp1); 1524 ntp->t_subt = nstp; 1525 return ntp; 1526 } 1527 1528 /* See C99 6.5.15 "Conditional operator". */ 1529 static tnode_t * 1530 build_colon(bool sys, tnode_t *ln, tnode_t *rn) 1531 { 1532 tspec_t lt = ln->tn_type->t_tspec; 1533 tspec_t rt = rn->tn_type->t_tspec; 1534 1535 type_t *tp; 1536 if (is_arithmetic(lt) && is_arithmetic(rt)) 1537 /* The operands were already balanced in build_binary. */ 1538 tp = ln->tn_type; 1539 else if (lt == BOOL && rt == BOOL) 1540 tp = ln->tn_type; 1541 else if (lt == VOID || rt == VOID) 1542 tp = gettyp(VOID); 1543 else if (is_struct_or_union(lt)) { 1544 lint_assert(is_struct_or_union(rt)); 1545 lint_assert(ln->tn_type->u.sou == rn->tn_type->u.sou); 1546 if (is_incomplete(ln->tn_type)) { 1547 /* unknown operand size, op '%s' */ 1548 error(138, op_name(COLON)); 1549 return NULL; 1550 } 1551 tp = ln->tn_type; 1552 } else if (lt == PTR && is_integer(rt)) { 1553 if (rt != PTRDIFF_TSPEC) 1554 rn = convert(NOOP, 0, gettyp(PTRDIFF_TSPEC), rn); 1555 tp = ln->tn_type; 1556 } else if (rt == PTR && is_integer(lt)) { 1557 if (lt != PTRDIFF_TSPEC) 1558 ln = convert(NOOP, 0, gettyp(PTRDIFF_TSPEC), ln); 1559 tp = rn->tn_type; 1560 } else if (lt == PTR && is_null_pointer(rn)) 1561 tp = merge_qualifiers(ln->tn_type, rn->tn_type); 1562 else if (rt == PTR && is_null_pointer(ln)) 1563 tp = merge_qualifiers(rn->tn_type, ln->tn_type); 1564 else if (lt == PTR && ln->tn_type->t_subt->t_tspec == VOID) 1565 tp = merge_qualifiers(ln->tn_type, rn->tn_type); 1566 else if (rt == PTR && rn->tn_type->t_subt->t_tspec == VOID) 1567 tp = merge_qualifiers(rn->tn_type, ln->tn_type); 1568 else { 1569 /* 1570 * XXX For now we simply take the left type. This is probably 1571 * wrong, if one type contains a function prototype and the 1572 * other one, at the same place, only an old-style declaration. 1573 */ 1574 tp = merge_qualifiers(ln->tn_type, rn->tn_type); 1575 } 1576 1577 return build_op(COLON, sys, tp, ln, rn); 1578 } 1579 1580 /* TODO: check for varargs */ 1581 static bool 1582 is_cast_redundant(const tnode_t *tn) 1583 { 1584 const type_t *ntp = tn->tn_type, *otp = tn->u.ops.left->tn_type; 1585 tspec_t nt = ntp->t_tspec, ot = otp->t_tspec; 1586 1587 if (nt == BOOL || ot == BOOL) 1588 return nt == BOOL && ot == BOOL; 1589 1590 if (is_integer(nt) && is_integer(ot)) { 1591 unsigned int nw = width_in_bits(ntp), ow = width_in_bits(otp); 1592 if (is_uinteger(nt) == is_uinteger(ot)) 1593 return nw >= ow; 1594 return is_uinteger(ot) && nw > ow; 1595 } 1596 1597 if (is_complex(nt) || is_complex(ot)) 1598 return is_complex(nt) && is_complex(ot) && 1599 size_in_bits(nt) >= size_in_bits(ot); 1600 1601 if (is_floating(nt) && is_floating(ot)) 1602 return size_in_bits(nt) >= size_in_bits(ot); 1603 1604 if (nt == PTR && ot == PTR) { 1605 if (!ntp->t_subt->t_const && otp->t_subt->t_const) 1606 return false; 1607 if (!ntp->t_subt->t_volatile && otp->t_subt->t_volatile) 1608 return false; 1609 1610 if (ntp->t_subt->t_tspec == VOID || 1611 otp->t_subt->t_tspec == VOID || 1612 types_compatible(ntp->t_subt, otp->t_subt, 1613 false, false, NULL)) 1614 return true; 1615 } 1616 1617 return false; 1618 } 1619 1620 static bool 1621 is_assignment(op_t op) 1622 { 1623 1624 return op == ASSIGN || 1625 op == MULASS || 1626 op == DIVASS || 1627 op == MODASS || 1628 op == ADDASS || 1629 op == SUBASS || 1630 op == SHLASS || 1631 op == SHRASS || 1632 op == ANDASS || 1633 op == XORASS || 1634 op == ORASS || 1635 op == RETURN || 1636 op == INIT; 1637 } 1638 1639 static tnode_t * 1640 build_assignment(op_t op, bool sys, tnode_t *ln, tnode_t *rn) 1641 { 1642 1643 tspec_t lt = ln->tn_type->t_tspec; 1644 tspec_t rt = rn->tn_type->t_tspec; 1645 1646 if (is_assignment(rn->tn_op)) 1647 /* chained assignment with '%s' and '%s' */ 1648 query_message(10, op_name(op), op_name(rn->tn_op)); 1649 1650 if ((op == ADDASS || op == SUBASS) && lt == PTR) { 1651 lint_assert(is_integer(rt)); 1652 tnode_t *ctn = subt_size_in_bytes(ln->tn_type); 1653 if (rn->tn_type->t_tspec != ctn->tn_type->t_tspec) 1654 rn = convert(NOOP, 0, ctn->tn_type, rn); 1655 rn = build_op(MULT, sys, rn->tn_type, rn, ctn); 1656 if (rn->u.ops.left->tn_op == CON) 1657 rn = fold_constant_integer(rn); 1658 } 1659 1660 if ((op == ASSIGN || op == RETURN || op == INIT) && 1661 (lt == STRUCT || rt == STRUCT)) { 1662 lint_assert(lt == rt); 1663 lint_assert(ln->tn_type->u.sou == rn->tn_type->u.sou); 1664 if (is_incomplete(ln->tn_type)) { 1665 if (op == RETURN) 1666 /* cannot return incomplete type */ 1667 error(212); 1668 else 1669 /* unknown operand size, op '%s' */ 1670 error(138, op_name(op)); 1671 return NULL; 1672 } 1673 } 1674 1675 if (op == SHLASS && hflag && allow_trad && allow_c90 1676 && portable_rank_cmp(lt, rt) < 0) 1677 /* semantics of '%s' change in C90; ... */ 1678 warning(118, "<<="); 1679 1680 if (op != SHLASS && op != SHRASS 1681 && (op == ASSIGN || lt != PTR) 1682 && (lt != rt || (ln->tn_type->t_bitfield && rn->tn_op == CON))) { 1683 rn = convert(op, 0, ln->tn_type, rn); 1684 rt = lt; 1685 } 1686 1687 if (lt == PTR && ln->tn_type->t_subt->t_tspec != VOID 1688 && rt == PTR && rn->tn_type->t_subt->t_tspec == VOID 1689 && !is_null_pointer(rn)) 1690 /* implicit narrowing conversion from void ... */ 1691 query_message(20, type_name(ln->tn_type)); 1692 1693 if (any_query_enabled && rn->tn_op == CVT && rn->tn_cast && 1694 types_compatible(ln->tn_type, rn->tn_type, false, false, NULL) && 1695 is_cast_redundant(rn)) { 1696 /* redundant cast from '%s' to '%s' before assignment */ 1697 query_message(7, type_name(rn->u.ops.left->tn_type), 1698 type_name(rn->tn_type)); 1699 } 1700 1701 return build_op(op, sys, ln->tn_type, ln, rn); 1702 } 1703 1704 static tnode_t * 1705 build_real_imag(op_t op, bool sys, tnode_t *ln) 1706 { 1707 1708 lint_assert(ln != NULL); 1709 if (ln->tn_op == NAME) { 1710 /* 1711 * This may be too much, but it avoids wrong warnings. See 1712 * d_c99_complex_split.c. 1713 */ 1714 mark_as_used(ln->u.sym, false, false); 1715 mark_as_set(ln->u.sym); 1716 } 1717 1718 tspec_t t; 1719 switch (ln->tn_type->t_tspec) { 1720 case LCOMPLEX: 1721 t = LDOUBLE; 1722 break; 1723 case DCOMPLEX: 1724 t = DOUBLE; 1725 break; 1726 case FCOMPLEX: 1727 t = FLOAT; 1728 break; 1729 default: 1730 /* '__%s__' is illegal for type '%s' */ 1731 error(276, op == REAL ? "real" : "imag", 1732 type_name(ln->tn_type)); 1733 return NULL; 1734 } 1735 1736 tnode_t *ntn = build_op(op, sys, gettyp(t), ln, NULL); 1737 ntn->tn_lvalue = true; 1738 return ntn; 1739 } 1740 1741 static bool 1742 is_confusing_precedence(op_t op, const tnode_t *operand, op_t *cop) 1743 { 1744 if (operand->tn_parenthesized) 1745 return false; 1746 op_t oop = operand->tn_op; 1747 1748 if (op == SHL || op == SHR) { 1749 if (oop == PLUS || oop == MINUS) 1750 return *cop = oop, true; 1751 return false; 1752 } 1753 1754 if (op == LOGOR) { 1755 if (oop == LOGAND) 1756 return *cop = oop, true; 1757 return false; 1758 } 1759 1760 lint_assert(op == BITAND || op == BITXOR || op == BITOR); 1761 if (oop != op 1762 && (oop == PLUS || oop == MINUS || oop == BITAND || oop == BITXOR)) 1763 return *cop = oop, true; 1764 return false; 1765 } 1766 1767 /* 1768 * Print a warning if the given node has operands which should be 1769 * parenthesized. 1770 * 1771 * XXX Does not work if an operand is a constant expression. Constant 1772 * expressions are already folded. 1773 */ 1774 static void 1775 check_precedence_confusion(tnode_t *tn) 1776 { 1777 tnode_t *ln, *rn; 1778 1779 if (!hflag) 1780 return; 1781 1782 debug_node(tn); 1783 1784 lint_assert(is_binary(tn)); 1785 for (ln = tn->u.ops.left; ln->tn_op == CVT; ln = ln->u.ops.left) 1786 continue; 1787 for (rn = tn->u.ops.right; rn->tn_op == CVT; rn = rn->u.ops.left) 1788 continue; 1789 1790 op_t cop; 1791 if (is_confusing_precedence(tn->tn_op, ln, &cop) || 1792 is_confusing_precedence(tn->tn_op, rn, &cop)) { 1793 /* possible precedence confusion between '%s' and '%s' */ 1794 warning(169, op_name(tn->tn_op), op_name(cop)); 1795 } 1796 } 1797 1798 static tnode_t * 1799 fold_constant_compare_zero(tnode_t *tn) 1800 { 1801 1802 val_t *v = xcalloc(1, sizeof(*v)); 1803 v->v_tspec = tn->tn_type->t_tspec; 1804 lint_assert(v->v_tspec == INT || (Tflag && v->v_tspec == BOOL)); 1805 1806 lint_assert(has_operands(tn)); 1807 bool l = constant_is_nonzero(tn->u.ops.left); 1808 bool r = is_binary(tn) && constant_is_nonzero(tn->u.ops.right); 1809 1810 switch (tn->tn_op) { 1811 case NOT: 1812 if (hflag && !suppress_constcond) 1813 /* constant operand to '!' */ 1814 warning(239); 1815 v->u.integer = !l ? 1 : 0; 1816 break; 1817 case LOGAND: 1818 v->u.integer = l && r ? 1 : 0; 1819 break; 1820 case LOGOR: 1821 v->u.integer = l || r ? 1 : 0; 1822 break; 1823 default: 1824 lint_assert(/*CONSTCOND*/false); 1825 } 1826 1827 return build_constant(tn->tn_type, v); 1828 } 1829 1830 static long double 1831 floating_error_value(tspec_t t, long double lv) 1832 { 1833 if (t == FLOAT) 1834 return lv < 0 ? -FLT_MAX : FLT_MAX; 1835 if (t == DOUBLE) 1836 return lv < 0 ? -DBL_MAX : DBL_MAX; 1837 /* 1838 * When NetBSD is cross-built in MKLINT=yes mode on x86_64 for sparc64, 1839 * tools/lint checks this code while building usr.bin/xlint. In that 1840 * situation, lint uses the preprocessor for sparc64, in which the type 1841 * 'long double' is IEEE-754-binary128, affecting the macro LDBL_MAX 1842 * below. The type 'long double', as well as the strtold 1843 * implementation, comes from the host platform x86_64 though, where 1844 * 'long double' consumes 128 bits as well but only uses 80 of them. 1845 * The exponent range of the two 'long double' types is the same, but 1846 * the maximum finite value differs due to the extended precision on 1847 * sparc64. 1848 * 1849 * To properly handle the data types of the target platform, lint would 1850 * have to implement the floating-point types in a platform-independent 1851 * way, which is not worth the effort, given how few programs 1852 * practically use 'long double'. 1853 */ 1854 /* LINTED 248: floating-point constant out of range */ 1855 long double max = LDBL_MAX; 1856 return lv < 0 ? -max : max; 1857 } 1858 1859 static bool 1860 is_floating_overflow(tspec_t t, long double val) 1861 { 1862 if (fpe != 0 || isfinite(val) == 0) 1863 return true; 1864 if (t == FLOAT && (val > FLT_MAX || val < -FLT_MAX)) 1865 return true; 1866 if (t == DOUBLE && (val > DBL_MAX || val < -DBL_MAX)) 1867 return true; 1868 return false; 1869 } 1870 1871 static tnode_t * 1872 fold_constant_floating(tnode_t *tn) 1873 { 1874 1875 fpe = 0; 1876 1877 tspec_t t = tn->tn_type->t_tspec; 1878 1879 val_t *v = xcalloc(1, sizeof(*v)); 1880 v->v_tspec = t; 1881 1882 lint_assert(is_floating(t)); 1883 lint_assert(has_operands(tn)); 1884 lint_assert(t == tn->u.ops.left->tn_type->t_tspec); 1885 lint_assert(!is_binary(tn) || t == tn->u.ops.right->tn_type->t_tspec); 1886 1887 long double lv = tn->u.ops.left->u.value.u.floating; 1888 long double rv = is_binary(tn) ? tn->u.ops.right->u.value.u.floating 1889 : 0.0; 1890 1891 switch (tn->tn_op) { 1892 case UPLUS: 1893 v->u.floating = lv; 1894 break; 1895 case UMINUS: 1896 v->u.floating = -lv; 1897 break; 1898 case MULT: 1899 v->u.floating = lv * rv; 1900 break; 1901 case DIV: 1902 if (rv == 0.0) { 1903 /* division by 0 */ 1904 error(139); 1905 v->u.floating = floating_error_value(t, lv); 1906 } else { 1907 v->u.floating = lv / rv; 1908 } 1909 break; 1910 case PLUS: 1911 v->u.floating = lv + rv; 1912 break; 1913 case MINUS: 1914 v->u.floating = lv - rv; 1915 break; 1916 case LT: 1917 v->u.integer = lv < rv ? 1 : 0; 1918 break; 1919 case LE: 1920 v->u.integer = lv <= rv ? 1 : 0; 1921 break; 1922 case GE: 1923 v->u.integer = lv >= rv ? 1 : 0; 1924 break; 1925 case GT: 1926 v->u.integer = lv > rv ? 1 : 0; 1927 break; 1928 case EQ: 1929 v->u.integer = lv == rv ? 1 : 0; 1930 break; 1931 case NE: 1932 v->u.integer = lv != rv ? 1 : 0; 1933 break; 1934 default: 1935 lint_assert(/*CONSTCOND*/false); 1936 } 1937 1938 // XXX: Must not access u.floating after setting u.integer. 1939 lint_assert(fpe != 0 || isnan(v->u.floating) == 0); 1940 if (is_complex(v->v_tspec)) { 1941 /* 1942 * Don't warn, as lint doesn't model the imaginary part of 1943 * complex numbers. 1944 */ 1945 fpe = 0; 1946 } else if (is_floating_overflow(t, v->u.floating)) { 1947 /* operator '%s' produces floating point overflow */ 1948 warning(142, op_name(tn->tn_op)); 1949 v->u.floating = floating_error_value(t, v->u.floating); 1950 fpe = 0; 1951 } 1952 1953 return build_constant(tn->tn_type, v); 1954 } 1955 1956 static void 1957 use(const tnode_t *tn) 1958 { 1959 if (tn == NULL) 1960 return; 1961 switch (tn->tn_op) { 1962 case NAME: 1963 mark_as_used(tn->u.sym, false /* XXX */, false /* XXX */); 1964 break; 1965 case CON: 1966 case STRING: 1967 break; 1968 case CALL:; 1969 const function_call *call = tn->u.call; 1970 for (size_t i = 0, n = call->args_len; i < n; i++) 1971 use(call->args[i]); 1972 break; 1973 default: 1974 lint_assert(has_operands(tn)); 1975 use(tn->u.ops.left); 1976 if (is_binary(tn)) 1977 use(tn->u.ops.right); 1978 } 1979 } 1980 1981 /* 1982 * Create a tree node for a binary operator and its two operands. Also called 1983 * for unary operators; in that case rn is NULL. 1984 * 1985 * Function calls, sizeof and casts are handled elsewhere. 1986 */ 1987 tnode_t * 1988 build_binary(tnode_t *ln, op_t op, bool sys, tnode_t *rn) 1989 { 1990 const mod_t *mp = &modtab[op]; 1991 1992 /* If there was an error in one of the operands, return. */ 1993 if (ln == NULL || (mp->m_binary && rn == NULL)) 1994 return NULL; 1995 1996 if (mp->m_value_context || mp->m_compares_with_zero) 1997 ln = cconv(ln); 1998 if (mp->m_binary && op != ARROW && op != POINT) 1999 rn = cconv(rn); 2000 2001 if (mp->m_comparison) 2002 check_integer_comparison(op, ln, rn); 2003 2004 if (mp->m_value_context || mp->m_compares_with_zero) 2005 ln = promote(op, false, ln); 2006 if (mp->m_binary && op != ARROW && op != POINT && 2007 op != ASSIGN && op != RETURN && op != INIT) 2008 rn = promote(op, false, rn); 2009 2010 if (mp->m_warn_if_left_unsigned_in_c90 && 2011 ln->tn_op == CON && ln->u.value.v_unsigned_since_c90) { 2012 /* C90 treats constant as unsigned, op '%s' */ 2013 warning(218, op_name(op)); 2014 ln->u.value.v_unsigned_since_c90 = false; 2015 } 2016 if (mp->m_warn_if_right_unsigned_in_c90 && 2017 rn->tn_op == CON && rn->u.value.v_unsigned_since_c90) { 2018 /* C90 treats constant as unsigned, op '%s' */ 2019 warning(218, op_name(op)); 2020 rn->u.value.v_unsigned_since_c90 = false; 2021 } 2022 2023 if (mp->m_balance_operands || (!allow_c90 && (op == SHL || op == SHR))) 2024 balance(op, &ln, &rn); 2025 2026 if (!typeok(op, 0, ln, rn)) 2027 return NULL; 2028 2029 tnode_t *ntn; 2030 switch (op) { 2031 case POINT: 2032 case ARROW: 2033 ntn = build_struct_access(op, sys, ln, rn); 2034 break; 2035 case NOT: 2036 if (ln->tn_op == ASSIGN && ln->u.ops.right->tn_op == CON) { 2037 /* constant assignment of type '%s' in operand ... */ 2038 warning(382, type_name(ln->tn_type), 2039 is_nonzero_val(&ln->u.ops.right->u.value) 2040 ? "true" : "false"); 2041 } 2042 ntn = build_op(op, sys, gettyp(Tflag ? BOOL : INT), ln, NULL); 2043 break; 2044 case INCAFT: 2045 case DECAFT: 2046 case INCBEF: 2047 case DECBEF: 2048 ntn = build_prepost_incdec(op, sys, ln); 2049 break; 2050 case ADDR: 2051 ntn = build_address(sys, ln); 2052 break; 2053 case INDIR: 2054 ntn = build_op(INDIR, sys, ln->tn_type->t_subt, ln, NULL); 2055 break; 2056 case PLUS: 2057 case MINUS: 2058 ntn = build_plus_minus(op, sys, ln, rn); 2059 break; 2060 case SHL: 2061 case SHR: 2062 ntn = build_bit_shift(op, sys, ln, rn); 2063 break; 2064 case COLON: 2065 ntn = build_colon(sys, ln, rn); 2066 break; 2067 case ASSIGN: 2068 case MULASS: 2069 case DIVASS: 2070 case MODASS: 2071 case ADDASS: 2072 case SUBASS: 2073 case SHLASS: 2074 case SHRASS: 2075 case ANDASS: 2076 case XORASS: 2077 case ORASS: 2078 case RETURN: 2079 case INIT: 2080 ntn = build_assignment(op, sys, ln, rn); 2081 break; 2082 case COMMA: 2083 /* comma operator with types '%s' and '%s' */ 2084 query_message(12, 2085 type_name(ln->tn_type), type_name(rn->tn_type)); 2086 /* FALLTHROUGH */ 2087 case QUEST: 2088 ntn = build_op(op, sys, rn->tn_type, ln, rn); 2089 break; 2090 case REAL: 2091 case IMAG: 2092 ntn = build_real_imag(op, sys, ln); 2093 break; 2094 default: 2095 lint_assert(mp->m_binary == (rn != NULL)); 2096 type_t *rettp = mp->m_returns_bool 2097 ? gettyp(Tflag ? BOOL : INT) : ln->tn_type; 2098 ntn = build_op(op, sys, rettp, ln, rn); 2099 break; 2100 } 2101 2102 if (ntn == NULL) 2103 return NULL; 2104 2105 if (mp->m_possible_precedence_confusion) 2106 check_precedence_confusion(ntn); 2107 2108 if (hflag && !suppress_constcond && 2109 mp->m_compares_with_zero && 2110 (ln->tn_op == CON || 2111 (mp->m_binary && op != QUEST && rn->tn_op == CON)) && 2112 /* XXX: rn->tn_system_dependent should be checked as well */ 2113 !ln->tn_system_dependent) 2114 /* constant in conditional context */ 2115 warning(161); 2116 2117 if (mp->m_fold_constant_operands && ln->tn_op == CON) { 2118 if (!mp->m_binary || rn->tn_op == CON) { 2119 if (mp->m_compares_with_zero) 2120 ntn = fold_constant_compare_zero(ntn); 2121 else if (is_floating(ntn->tn_type->t_tspec)) 2122 ntn = fold_constant_floating(ntn); 2123 else 2124 ntn = fold_constant_integer(ntn); 2125 } else if (op == QUEST) { 2126 lint_assert(has_operands(rn)); 2127 use(ln->u.value.u.integer != 0 2128 ? rn->u.ops.right : rn->u.ops.left); 2129 ntn = ln->u.value.u.integer != 0 2130 ? rn->u.ops.left : rn->u.ops.right; 2131 } 2132 } 2133 2134 return ntn; 2135 } 2136 2137 tnode_t * 2138 build_unary(op_t op, bool sys, tnode_t *tn) 2139 { 2140 return build_binary(tn, op, sys, NULL); 2141 } 2142 2143 static bool 2144 are_members_compatible(const sym_t *a, const sym_t *b) 2145 { 2146 if (a->u.s_member.sm_offset_in_bits != b->u.s_member.sm_offset_in_bits) 2147 return false; 2148 2149 const type_t *atp = a->s_type; 2150 const type_t *btp = b->s_type; 2151 bool w = false; 2152 if (!types_compatible(atp, btp, false, false, &w) && !w) 2153 return false; 2154 if (a->s_bitfield != b->s_bitfield) 2155 return false; 2156 if (a->s_bitfield) { 2157 if (atp->t_bit_field_width != btp->t_bit_field_width) 2158 return false; 2159 if (atp->t_bit_field_offset != btp->t_bit_field_offset) 2160 return false; 2161 } 2162 return true; 2163 } 2164 2165 /* 2166 * Return whether all struct/union members with the same name have the same 2167 * type and offset. 2168 */ 2169 static bool 2170 all_members_compatible(const sym_t *msym) 2171 { 2172 for (const sym_t *csym = msym; 2173 csym != NULL; csym = csym->s_symtab_next) { 2174 if (!is_member(csym)) 2175 continue; 2176 if (strcmp(msym->s_name, csym->s_name) != 0) 2177 continue; 2178 2179 for (const sym_t *sym = csym->s_symtab_next; 2180 sym != NULL; sym = sym->s_symtab_next) { 2181 if (is_member(sym) 2182 && strcmp(csym->s_name, sym->s_name) == 0 2183 && !are_members_compatible(csym, sym)) 2184 return false; 2185 } 2186 } 2187 return true; 2188 } 2189 2190 sym_t * 2191 find_member(const struct_or_union *sou, const char *name) 2192 { 2193 for (sym_t *mem = sou->sou_first_member; 2194 mem != NULL; mem = mem->s_next) { 2195 lint_assert(is_member(mem)); 2196 lint_assert(mem->u.s_member.sm_containing_type == sou); 2197 if (strcmp(mem->s_name, name) == 0) 2198 return mem; 2199 } 2200 2201 for (sym_t *mem = sou->sou_first_member; 2202 mem != NULL; mem = mem->s_next) { 2203 if (is_struct_or_union(mem->s_type->t_tspec) 2204 && mem->s_name == unnamed) { 2205 sym_t *nested_mem = 2206 find_member(mem->s_type->u.sou, name); 2207 if (nested_mem != NULL) 2208 return nested_mem; 2209 } 2210 } 2211 return NULL; 2212 } 2213 2214 /* 2215 * Remove the member if it was unknown until now, which means 2216 * that no defined struct or union has a member with the same name. 2217 */ 2218 static void 2219 remove_unknown_member(tnode_t *tn, sym_t *msym) 2220 { 2221 /* type '%s' does not have member '%s' */ 2222 error(101, type_name(tn->tn_type), msym->s_name); 2223 symtab_remove_forever(msym); 2224 msym->s_kind = SK_MEMBER; 2225 msym->s_scl = STRUCT_MEMBER; 2226 2227 struct_or_union *sou = expr_zero_alloc(sizeof(*sou), 2228 "struct_or_union"); 2229 sou->sou_tag = expr_zero_alloc(sizeof(*sou->sou_tag), "sym"); 2230 sou->sou_tag->s_name = unnamed; 2231 2232 msym->u.s_member.sm_containing_type = sou; 2233 /* 2234 * The member sm_offset_in_bits is not needed here since this symbol 2235 * can only be used for error reporting. 2236 */ 2237 } 2238 2239 /* 2240 * Returns a symbol which has the same name as 'msym' and is a member of the 2241 * struct or union specified by 'tn'. 2242 */ 2243 static sym_t * 2244 struct_or_union_member(tnode_t *tn, op_t op, sym_t *msym) 2245 { 2246 2247 /* Determine the tag type of which msym is expected to be a member. */ 2248 const type_t *tp = NULL; 2249 if (op == POINT && is_struct_or_union(tn->tn_type->t_tspec)) 2250 tp = tn->tn_type; 2251 if (op == ARROW && tn->tn_type->t_tspec == PTR 2252 && is_struct_or_union(tn->tn_type->t_subt->t_tspec)) 2253 tp = tn->tn_type->t_subt; 2254 struct_or_union *sou = tp != NULL ? tp->u.sou : NULL; 2255 2256 if (sou != NULL) { 2257 sym_t *nested_mem = find_member(sou, msym->s_name); 2258 if (nested_mem != NULL) 2259 return nested_mem; 2260 } 2261 2262 if (msym->s_scl == NO_SCL) { 2263 remove_unknown_member(tn, msym); 2264 return msym; 2265 } 2266 2267 bool eq = all_members_compatible(msym); 2268 2269 /* 2270 * Now handle the case in which the left operand refers really to a 2271 * struct/union, but the right operand is not member of it. 2272 */ 2273 if (sou != NULL) { 2274 if (eq && !allow_c90) 2275 /* illegal use of member '%s' */ 2276 warning(102, msym->s_name); 2277 else 2278 /* illegal use of member '%s' */ 2279 error(102, msym->s_name); 2280 return msym; 2281 } 2282 2283 if (eq) { 2284 if (op == POINT) { 2285 if (!allow_c90) 2286 /* left operand of '.' must be struct ... */ 2287 warning(103, type_name(tn->tn_type)); 2288 else 2289 /* left operand of '.' must be struct ... */ 2290 error(103, type_name(tn->tn_type)); 2291 } else { 2292 if (!allow_c90 && tn->tn_type->t_tspec == PTR) 2293 /* left operand of '->' must be pointer ... */ 2294 warning(104, type_name(tn->tn_type)); 2295 else 2296 /* left operand of '->' must be pointer ... */ 2297 error(104, type_name(tn->tn_type)); 2298 } 2299 } else { 2300 if (!allow_c90) 2301 /* non-unique member requires struct/union %s */ 2302 error(105, op == POINT ? "object" : "pointer"); 2303 else 2304 /* unacceptable operand of '%s' */ 2305 error(111, op_name(op)); 2306 } 2307 2308 return msym; 2309 } 2310 2311 tnode_t * 2312 build_member_access(tnode_t *ln, op_t op, bool sys, sbuf_t *member) 2313 { 2314 sym_t *msym; 2315 2316 if (ln == NULL) 2317 return NULL; 2318 2319 if (op == ARROW) 2320 /* must do this before struct_or_union_member is called */ 2321 ln = cconv(ln); 2322 msym = struct_or_union_member(ln, op, getsym(member)); 2323 return build_binary(ln, op, sys, build_name(msym, false)); 2324 } 2325 2326 /* 2327 * Perform class conversions. 2328 * 2329 * Arrays of type T are converted into pointers to type T. 2330 * Functions are converted to pointers to functions. 2331 * Lvalues are converted to rvalues. 2332 * 2333 * C99 6.3 "Conversions" 2334 * C99 6.3.2 "Other operands" 2335 * C99 6.3.2.1 "Lvalues, arrays, and function designators" 2336 */ 2337 tnode_t * 2338 cconv(tnode_t *tn) 2339 { 2340 if (tn->tn_type->t_tspec == ARRAY) { 2341 if (!tn->tn_lvalue) { 2342 /* XXX print correct operator */ 2343 /* %soperand of '%s' must be lvalue */ 2344 gnuism(114, "", op_name(ADDR)); 2345 } 2346 tn = build_op(ADDR, tn->tn_sys, 2347 expr_derive_type(tn->tn_type->t_subt, PTR), tn, NULL); 2348 } 2349 2350 if (tn->tn_type->t_tspec == FUNC) 2351 tn = build_address(tn->tn_sys, tn); 2352 2353 if (tn->tn_lvalue) { 2354 type_t *tp = expr_dup_type(tn->tn_type); 2355 /* C99 6.3.2.1p2 sentence 2 says to remove the qualifiers. */ 2356 tp->t_const = tp->t_volatile = false; 2357 tn = build_op(LOAD, tn->tn_sys, tp, tn, NULL); 2358 } 2359 2360 return tn; 2361 } 2362 2363 const tnode_t * 2364 before_conversion(const tnode_t *tn) 2365 { 2366 while (tn->tn_op == CVT && !tn->tn_cast) 2367 tn = tn->u.ops.left; 2368 return tn; 2369 } 2370 2371 /* 2372 * Most errors required by C90 are reported in struct_or_union_member(). 2373 * Here we only check for totally wrong things. 2374 */ 2375 static bool 2376 typeok_point(const tnode_t *ln, const type_t *ltp, tspec_t lt) 2377 { 2378 if (is_struct_or_union(lt)) 2379 return true; 2380 2381 if (lt == FUNC || lt == VOID || ltp->t_bitfield) 2382 goto wrong; 2383 2384 /* 2385 * Some C dialects from before C90 tolerated any lvalue on the 2386 * left-hand side of the '.' operator, allowing things like 'char 2387 * st[100]; st.st_mtime', assuming that the member 'st_mtime' only 2388 * occurred in a single struct; see typeok_arrow. 2389 */ 2390 if (ln->tn_lvalue) 2391 return true; 2392 2393 wrong: 2394 /* With allow_c90 we already got an error */ 2395 if (!allow_c90) 2396 /* unacceptable operand of '%s' */ 2397 error(111, op_name(POINT)); 2398 2399 return false; 2400 } 2401 2402 static bool 2403 typeok_arrow(tspec_t lt) 2404 { 2405 /* 2406 * C1978 Appendix A 14.1 says: <quote>In fact, any lvalue is allowed 2407 * before '.', and that lvalue is then assumed to have the form of the 2408 * structure of which the name of the right is a member. [...] Such 2409 * constructions are non-portable.</quote> 2410 */ 2411 if (lt == PTR || (!allow_c90 && is_integer(lt))) 2412 return true; 2413 2414 /* With allow_c90 we already got an error */ 2415 if (!allow_c90) 2416 /* unacceptable operand of '%s' */ 2417 error(111, op_name(ARROW)); 2418 return false; 2419 } 2420 2421 static bool 2422 typeok_incdec(op_t op, const tnode_t *tn, const type_t *tp) 2423 { 2424 /* operand has scalar type (checked in typeok) */ 2425 if (!tn->tn_lvalue) { 2426 if (tn->tn_op == CVT && tn->tn_cast && 2427 tn->u.ops.left->tn_op == LOAD) 2428 /* a cast does not yield an lvalue */ 2429 error(163); 2430 /* %soperand of '%s' must be lvalue */ 2431 error(114, "", op_name(op)); 2432 return false; 2433 } 2434 if (tp->t_const && allow_c90) 2435 /* %soperand of '%s' must be modifiable lvalue */ 2436 warning(115, "", op_name(op)); 2437 return true; 2438 } 2439 2440 static bool 2441 typeok_address(op_t op, const tnode_t *tn, const type_t *tp, tspec_t t) 2442 { 2443 if (t == ARRAY || t == FUNC) { 2444 /* ok, a warning comes later (in build_address()) */ 2445 } else if (!tn->tn_lvalue) { 2446 if (tn->tn_op == CVT && tn->tn_cast && 2447 tn->u.ops.left->tn_op == LOAD) 2448 /* a cast does not yield an lvalue */ 2449 error(163); 2450 /* %soperand of '%s' must be lvalue */ 2451 error(114, "", op_name(op)); 2452 return false; 2453 } else if (is_scalar(t)) { 2454 if (tp->t_bitfield) { 2455 /* cannot take address of bit-field */ 2456 error(112); 2457 return false; 2458 } 2459 } else if (t != STRUCT && t != UNION) { 2460 /* unacceptable operand of '%s' */ 2461 error(111, op_name(op)); 2462 return false; 2463 } 2464 if (tn->tn_op == NAME && tn->u.sym->s_register) { 2465 /* cannot take address of register '%s' */ 2466 error(113, tn->u.sym->s_name); 2467 return false; 2468 } 2469 return true; 2470 } 2471 2472 static bool 2473 typeok_indir(const type_t *tp, tspec_t t) 2474 { 2475 2476 if (t != PTR) { 2477 /* cannot dereference non-pointer type '%s' */ 2478 error(96, type_name(tp)); 2479 return false; 2480 } 2481 return true; 2482 } 2483 2484 static void 2485 warn_incompatible_types(op_t op, 2486 const type_t *ltp, tspec_t lt, 2487 const type_t *rtp, tspec_t rt) 2488 { 2489 bool binary = modtab[op].m_binary; 2490 2491 if (lt == VOID || (binary && rt == VOID)) { 2492 /* void type illegal in expression */ 2493 error(109); 2494 } else if (op == ASSIGN) 2495 /* cannot assign to '%s' from '%s' */ 2496 error(171, type_name(ltp), type_name(rtp)); 2497 else if (binary) 2498 /* operands of '%s' have incompatible types '%s' and '%s' */ 2499 error(107, op_name(op), type_name(ltp), type_name(rtp)); 2500 else { 2501 lint_assert(rt == NO_TSPEC); 2502 /* operand of '%s' has invalid type '%s' */ 2503 error(108, op_name(op), type_name(ltp)); 2504 } 2505 } 2506 2507 static bool 2508 typeok_plus(op_t op, 2509 const type_t *ltp, tspec_t lt, 2510 const type_t *rtp, tspec_t rt) 2511 { 2512 /* operands have scalar types (checked in typeok) */ 2513 if ((lt == PTR && !is_integer(rt)) || (rt == PTR && !is_integer(lt))) { 2514 warn_incompatible_types(op, ltp, lt, rtp, rt); 2515 return false; 2516 } 2517 return true; 2518 } 2519 2520 static bool 2521 typeok_minus(op_t op, 2522 const type_t *ltp, tspec_t lt, 2523 const type_t *rtp, tspec_t rt) 2524 { 2525 /* operands have scalar types (checked in typeok) */ 2526 if ((lt == PTR && rt != PTR && !is_integer(rt)) || 2527 (lt != PTR && rt == PTR)) { 2528 warn_incompatible_types(op, ltp, lt, rtp, rt); 2529 return false; 2530 } 2531 if (lt == PTR && rt == PTR && 2532 !types_compatible(ltp->t_subt, rtp->t_subt, true, false, NULL)) { 2533 /* illegal pointer subtraction */ 2534 error(116); 2535 } 2536 return true; 2537 } 2538 2539 static void 2540 typeok_shr(op_t op, 2541 const tnode_t *ln, tspec_t lt, 2542 const tnode_t *rn, tspec_t rt) 2543 { 2544 tspec_t olt = before_conversion(ln)->tn_type->t_tspec; 2545 tspec_t ort = before_conversion(rn)->tn_type->t_tspec; 2546 2547 /* operands have integer types (checked in typeok) */ 2548 if (pflag && !is_uinteger(olt)) { 2549 integer_constraints lc = ic_expr(ln); 2550 if (lc.bclr >> 63 != 0) 2551 return; 2552 2553 if (ln->tn_op != CON) 2554 /* bitwise '%s' on signed value possibly nonportable */ 2555 warning(117, op_name(op)); 2556 else if (ln->u.value.u.integer < 0) 2557 /* bitwise '%s' on signed value nonportable */ 2558 warning(120, op_name(op)); 2559 } else if (allow_trad && allow_c90 && 2560 !is_uinteger(olt) && is_uinteger(ort)) { 2561 /* The left operand would become unsigned in traditional C. */ 2562 if (hflag && (ln->tn_op != CON || ln->u.value.u.integer < 0)) { 2563 /* semantics of '%s' change in C90; use ... */ 2564 warning(118, op_name(op)); 2565 } 2566 } else if (allow_trad && allow_c90 && 2567 !is_uinteger(olt) && !is_uinteger(ort) && 2568 portable_rank_cmp(lt, rt) < 0) { 2569 /* 2570 * In traditional C, the left operand would be extended 2571 * (possibly sign-extended) and then shifted. 2572 */ 2573 if (hflag && (ln->tn_op != CON || ln->u.value.u.integer < 0)) { 2574 /* semantics of '%s' change in C90; use ... */ 2575 warning(118, op_name(op)); 2576 } 2577 } 2578 } 2579 2580 static void 2581 typeok_shl(op_t op, tspec_t lt, tspec_t rt) 2582 { 2583 /* 2584 * C90 does not perform balancing for shift operations, but traditional 2585 * C does. If the width of the right operand is greater than the width 2586 * of the left operand, then in traditional C the left operand would be 2587 * extended to the width of the right operand. For SHL this may result 2588 * in different results. 2589 */ 2590 if (portable_rank_cmp(lt, rt) < 0) { 2591 /* 2592 * XXX If both operands are constant, make sure that there is 2593 * really a difference between C90 and traditional C. 2594 */ 2595 if (hflag && allow_trad && allow_c90) 2596 /* semantics of '%s' change in C90; use ... */ 2597 warning(118, op_name(op)); 2598 } 2599 } 2600 2601 static void 2602 typeok_shift(const type_t *ltp, tspec_t lt, const tnode_t *rn, tspec_t rt) 2603 { 2604 if (rn->tn_op != CON) 2605 return; 2606 2607 if (!is_uinteger(rt) && rn->u.value.u.integer < 0) 2608 /* negative shift */ 2609 warning(121); 2610 else if ((uint64_t)rn->u.value.u.integer == size_in_bits(lt)) 2611 /* shift amount %u equals bit-size of '%s' */ 2612 warning(267, (unsigned)rn->u.value.u.integer, type_name(ltp)); 2613 else if ((uint64_t)rn->u.value.u.integer > size_in_bits(lt)) { 2614 /* shift amount %llu is greater than bit-size %llu of '%s' */ 2615 warning(122, (unsigned long long)rn->u.value.u.integer, 2616 (unsigned long long)size_in_bits(lt), 2617 tspec_name(lt)); 2618 } 2619 } 2620 2621 static bool 2622 is_typeok_eq(const tnode_t *ln, tspec_t lt, const tnode_t *rn, tspec_t rt) 2623 { 2624 if (lt == PTR && is_null_pointer(rn)) 2625 return true; 2626 if (rt == PTR && is_null_pointer(ln)) 2627 return true; 2628 return false; 2629 } 2630 2631 static void 2632 warn_incompatible_pointers(op_t op, const type_t *ltp, const type_t *rtp) 2633 { 2634 lint_assert(ltp->t_tspec == PTR); 2635 lint_assert(rtp->t_tspec == PTR); 2636 2637 tspec_t lt = ltp->t_subt->t_tspec; 2638 tspec_t rt = rtp->t_subt->t_tspec; 2639 2640 if (is_struct_or_union(lt) && is_struct_or_union(rt)) { 2641 if (op == RETURN) 2642 /* illegal structure pointer combination */ 2643 warning(244); 2644 else { 2645 /* incompatible structure pointers: '%s' '%s' '%s' */ 2646 warning(245, type_name(ltp), 2647 op_name(op), type_name(rtp)); 2648 } 2649 } else { 2650 if (op == RETURN) 2651 /* illegal combination of '%s' and '%s' */ 2652 warning(184, type_name(ltp), type_name(rtp)); 2653 else { 2654 /* illegal combination of '%s' and '%s', op '%s' */ 2655 warning(124, 2656 type_name(ltp), type_name(rtp), op_name(op)); 2657 } 2658 } 2659 } 2660 2661 static void 2662 check_pointer_comparison(op_t op, const tnode_t *ln, const tnode_t *rn) 2663 { 2664 type_t *ltp = ln->tn_type, *rtp = rn->tn_type; 2665 tspec_t lst = ltp->t_subt->t_tspec, rst = rtp->t_subt->t_tspec; 2666 2667 if (lst == VOID || rst == VOID) { 2668 /* TODO: C99 behaves like C90 here. */ 2669 if (!allow_trad && !allow_c99 && 2670 (lst == FUNC || rst == FUNC)) { 2671 /* (void *)0 is already handled in typeok() */ 2672 const char *lsts, *rsts; 2673 *(lst == FUNC ? &lsts : &rsts) = "function pointer"; 2674 *(lst == VOID ? &lsts : &rsts) = "'void *'"; 2675 /* C90 or later forbid comparison of %s with %s */ 2676 warning(274, lsts, rsts); 2677 } 2678 return; 2679 } 2680 2681 if (!types_compatible(ltp->t_subt, rtp->t_subt, true, false, NULL)) { 2682 warn_incompatible_pointers(op, ltp, rtp); 2683 return; 2684 } 2685 2686 if (lst == FUNC && rst == FUNC) { 2687 /* TODO: C99 behaves like C90 here, see C99 6.5.8p2. */ 2688 if (!allow_trad && !allow_c99 && op != EQ && op != NE) 2689 /* pointers to functions can only be compared ... */ 2690 warning(125); 2691 } 2692 } 2693 2694 static bool 2695 typeok_compare(op_t op, 2696 const tnode_t *ln, const type_t *ltp, tspec_t lt, 2697 const tnode_t *rn, const type_t *rtp, tspec_t rt) 2698 { 2699 if (lt == PTR && rt == PTR) { 2700 check_pointer_comparison(op, ln, rn); 2701 return true; 2702 } 2703 2704 if (lt != PTR && rt != PTR) 2705 return true; 2706 2707 if (!is_integer(lt) && !is_integer(rt)) { 2708 warn_incompatible_types(op, ltp, lt, rtp, rt); 2709 return false; 2710 } 2711 2712 const char *lx = lt == PTR ? "pointer" : "integer"; 2713 const char *rx = rt == PTR ? "pointer" : "integer"; 2714 /* illegal combination of %s '%s' and %s '%s', op '%s' */ 2715 warning(123, lx, type_name(ltp), rx, type_name(rtp), op_name(op)); 2716 return true; 2717 } 2718 2719 static bool 2720 typeok_quest(tspec_t lt, const tnode_t *rn) 2721 { 2722 if (!is_scalar(lt)) { 2723 /* first operand of '?' must have scalar type */ 2724 error(170); 2725 return false; 2726 } 2727 lint_assert(before_conversion(rn)->tn_op == COLON); 2728 return true; 2729 } 2730 2731 static void 2732 typeok_colon_pointer(const type_t *ltp, const type_t *rtp) 2733 { 2734 type_t *lstp = ltp->t_subt; 2735 type_t *rstp = rtp->t_subt; 2736 tspec_t lst = lstp->t_tspec; 2737 tspec_t rst = rstp->t_tspec; 2738 2739 if ((lst == VOID && rst == FUNC) || (lst == FUNC && rst == VOID)) { 2740 /* (void *)0 is handled in typeok_colon */ 2741 /* TODO: C99 behaves like C90 here. */ 2742 if (!allow_trad && !allow_c99) 2743 /* conversion of %s to %s requires a cast, op %s */ 2744 warning(305, "function pointer", "'void *'", 2745 op_name(COLON)); 2746 return; 2747 } 2748 2749 if (pointer_types_are_compatible(lstp, rstp, true)) 2750 return; 2751 if (!types_compatible(lstp, rstp, true, false, NULL)) 2752 warn_incompatible_pointers(COLON, ltp, rtp); 2753 } 2754 2755 static bool 2756 typeok_colon(const tnode_t *ln, const type_t *ltp, tspec_t lt, 2757 const tnode_t *rn, const type_t *rtp, tspec_t rt) 2758 { 2759 2760 if (is_arithmetic(lt) && is_arithmetic(rt)) 2761 return true; 2762 if (lt == BOOL && rt == BOOL) 2763 return true; 2764 2765 if (lt == STRUCT && rt == STRUCT && ltp->u.sou == rtp->u.sou) 2766 return true; 2767 if (lt == UNION && rt == UNION && ltp->u.sou == rtp->u.sou) 2768 return true; 2769 2770 if (lt == PTR && is_null_pointer(rn)) 2771 return true; 2772 if (rt == PTR && is_null_pointer(ln)) 2773 return true; 2774 2775 if ((lt == PTR && is_integer(rt)) || (is_integer(lt) && rt == PTR)) { 2776 const char *lx = lt == PTR ? "pointer" : "integer"; 2777 const char *rx = rt == PTR ? "pointer" : "integer"; 2778 /* illegal combination of %s '%s' and %s '%s', op '%s' */ 2779 warning(123, lx, type_name(ltp), 2780 rx, type_name(rtp), op_name(COLON)); 2781 return true; 2782 } 2783 2784 if (lt == VOID || rt == VOID) { 2785 if (lt != VOID || rt != VOID) 2786 /* incompatible types '%s' and '%s' in conditional */ 2787 warning(126, type_name(ltp), type_name(rtp)); 2788 return true; 2789 } 2790 2791 if (lt == PTR && rt == PTR) { 2792 typeok_colon_pointer(ltp, rtp); 2793 return true; 2794 } 2795 2796 /* incompatible types '%s' and '%s' in conditional */ 2797 error(126, type_name(ltp), type_name(rtp)); 2798 return false; 2799 } 2800 2801 static bool 2802 has_constant_member(const type_t *tp) 2803 { 2804 lint_assert(is_struct_or_union(tp->t_tspec)); 2805 2806 for (sym_t *m = tp->u.sou->sou_first_member; 2807 m != NULL; m = m->s_next) { 2808 const type_t *mtp = m->s_type; 2809 if (mtp->t_const) 2810 return true; 2811 if (is_struct_or_union(mtp->t_tspec) && 2812 has_constant_member(mtp)) 2813 return true; 2814 } 2815 return false; 2816 } 2817 2818 static bool 2819 typeok_assign(op_t op, const tnode_t *ln, const type_t *ltp, tspec_t lt) 2820 { 2821 if (op == RETURN || op == INIT || op == FARG) 2822 return true; 2823 2824 if (!ln->tn_lvalue) { 2825 if (ln->tn_op == CVT && ln->tn_cast && 2826 ln->u.ops.left->tn_op == LOAD) 2827 /* a cast does not yield an lvalue */ 2828 error(163); 2829 /* %soperand of '%s' must be lvalue */ 2830 error(114, "left ", op_name(op)); 2831 return false; 2832 } else if (ltp->t_const 2833 || (is_struct_or_union(lt) && has_constant_member(ltp))) { 2834 if (allow_c90) 2835 /* %soperand of '%s' must be modifiable lvalue */ 2836 warning(115, "left ", op_name(op)); 2837 } 2838 return true; 2839 } 2840 2841 static bool 2842 typeok_scalar(op_t op, const mod_t *mp, 2843 const type_t *ltp, tspec_t lt, 2844 const type_t *rtp, tspec_t rt) 2845 { 2846 if (mp->m_takes_bool && lt == BOOL && rt == BOOL) 2847 return true; 2848 if (mp->m_requires_integer) { 2849 if (!is_integer(lt) || (mp->m_binary && !is_integer(rt))) { 2850 warn_incompatible_types(op, ltp, lt, rtp, rt); 2851 return false; 2852 } 2853 } else if (mp->m_requires_integer_or_complex) { 2854 if ((!is_integer(lt) && !is_complex(lt)) || 2855 (mp->m_binary && (!is_integer(rt) && !is_complex(rt)))) { 2856 warn_incompatible_types(op, ltp, lt, rtp, rt); 2857 return false; 2858 } 2859 } else if (mp->m_requires_scalar) { 2860 if (!is_scalar(lt) || (mp->m_binary && !is_scalar(rt))) { 2861 warn_incompatible_types(op, ltp, lt, rtp, rt); 2862 return false; 2863 } 2864 } else if (mp->m_requires_arith) { 2865 if (!is_arithmetic(lt) || 2866 (mp->m_binary && !is_arithmetic(rt))) { 2867 warn_incompatible_types(op, ltp, lt, rtp, rt); 2868 return false; 2869 } 2870 } 2871 return true; 2872 } 2873 2874 static void 2875 check_assign_void_pointer(op_t op, int arg, 2876 tspec_t lt, tspec_t lst, 2877 tspec_t rt, tspec_t rst) 2878 { 2879 2880 if (!(lt == PTR && rt == PTR && (lst == VOID || rst == VOID))) 2881 return; 2882 /* two pointers, at least one pointer to void */ 2883 2884 /* TODO: C99 behaves like C90 here. */ 2885 if (!(!allow_trad && !allow_c99 && (lst == FUNC || rst == FUNC))) 2886 return; 2887 /* comb. of ptr to func and ptr to void */ 2888 2889 const char *lts, *rts; 2890 *(lst == FUNC ? <s : &rts) = "function pointer"; 2891 *(lst == VOID ? <s : &rts) = "'void *'"; 2892 2893 switch (op) { 2894 case INIT: 2895 case RETURN: 2896 /* conversion of %s to %s requires a cast */ 2897 warning(303, rts, lts); 2898 break; 2899 case FARG: 2900 /* conversion of %s to %s requires a cast, arg #%d */ 2901 warning(304, rts, lts, arg); 2902 break; 2903 default: 2904 /* conversion of %s to %s requires a cast, op %s */ 2905 warning(305, rts, lts, op_name(op)); 2906 break; 2907 } 2908 } 2909 2910 static bool 2911 is_direct_function_call(const tnode_t *tn, const char **out_name) 2912 { 2913 2914 if (tn->tn_op == CALL 2915 && tn->u.call->func->tn_op == ADDR 2916 && tn->u.call->func->u.ops.left->tn_op == NAME) { 2917 *out_name = tn->u.call->func->u.ops.left->u.sym->s_name; 2918 return true; 2919 } 2920 return false; 2921 } 2922 2923 static bool 2924 is_unconst_function(const char *name) 2925 { 2926 2927 return strcmp(name, "memchr") == 0 || 2928 strcmp(name, "strchr") == 0 || 2929 strcmp(name, "strpbrk") == 0 || 2930 strcmp(name, "strrchr") == 0 || 2931 strcmp(name, "strstr") == 0; 2932 } 2933 2934 static bool 2935 is_const_char_pointer(const tnode_t *tn) 2936 { 2937 /* 2938 * For traditional reasons, C99 6.4.5p5 defines that string literals 2939 * have type 'char[]'. They are often implicitly converted to 'char 2940 * *', for example when they are passed as function arguments. 2941 * 2942 * C99 6.4.5p6 further defines that modifying a string that is 2943 * constructed from a string literal invokes undefined behavior. 2944 * 2945 * Out of these reasons, string literals are treated as 'effectively 2946 * const' here. 2947 */ 2948 if (tn->tn_op == CVT && 2949 tn->u.ops.left->tn_op == ADDR && 2950 tn->u.ops.left->u.ops.left->tn_op == STRING) 2951 return true; 2952 2953 const type_t *tp = before_conversion(tn)->tn_type; 2954 return tp->t_tspec == PTR && 2955 tp->t_subt->t_tspec == CHAR && 2956 tp->t_subt->t_const; 2957 } 2958 2959 static bool 2960 is_const_pointer(const tnode_t *tn) 2961 { 2962 const type_t *tp = before_conversion(tn)->tn_type; 2963 return tp->t_tspec == PTR && tp->t_subt->t_const; 2964 } 2965 2966 static void 2967 check_unconst_function(const type_t *lstp, const tnode_t *rn) 2968 { 2969 const char *function_name; 2970 2971 if (lstp->t_tspec == CHAR && !lstp->t_const && 2972 is_direct_function_call(rn, &function_name) && 2973 is_unconst_function(function_name) && 2974 rn->u.call->args_len >= 1 && 2975 is_const_char_pointer(rn->u.call->args[0])) { 2976 /* call to '%s' effectively discards 'const' from argument */ 2977 warning(346, function_name); 2978 } 2979 2980 if (!lstp->t_const && 2981 is_direct_function_call(rn, &function_name) && 2982 strcmp(function_name, "bsearch") == 0 && 2983 rn->u.call->args_len >= 2 && 2984 is_const_pointer(rn->u.call->args[1])) { 2985 /* call to '%s' effectively discards 'const' from argument */ 2986 warning(346, function_name); 2987 } 2988 } 2989 2990 static bool 2991 check_assign_void_pointer_compat(op_t op, int arg, 2992 tspec_t lt, 2993 const type_t *lstp, tspec_t lst, 2994 const tnode_t *rn, 2995 const type_t *rtp, tspec_t rt, 2996 const type_t *rstp, tspec_t rst) 2997 { 2998 if (!(lt == PTR && rt == PTR && (lst == VOID || rst == VOID || 2999 types_compatible(lstp, rstp, 3000 true, false, NULL)))) 3001 return false; 3002 3003 /* compatible pointer types (qualifiers ignored) */ 3004 char qualifiers[32]; 3005 snprintf(qualifiers, sizeof(qualifiers), "%s%s", 3006 !lstp->t_const && rstp->t_const ? " const" : "", 3007 !lstp->t_volatile && rstp->t_volatile ? " volatile" : ""); 3008 if (allow_c90 && qualifiers[0] != '\0') { 3009 switch (op) { 3010 case INIT: 3011 case RETURN: 3012 /* '%s' discards '%s' from '%s' */ 3013 warning(182, op_name(op), 3014 qualifiers + 1, type_name(rtp)); 3015 break; 3016 case FARG: 3017 /* passing '%s' to argument %d discards '%s' */ 3018 warning(383, type_name(rtp), arg, qualifiers + 1); 3019 break; 3020 default: 3021 /* operator '%s' discards '%s' from '%s' */ 3022 warning(128, op_name(op), 3023 qualifiers + 1, type_name(rtp)); 3024 break; 3025 } 3026 } 3027 3028 if (allow_c90) 3029 check_unconst_function(lstp, rn); 3030 3031 return true; 3032 } 3033 3034 static bool 3035 check_assign_pointer_integer(op_t op, int arg, 3036 const type_t *ltp, tspec_t lt, 3037 const type_t *rtp, tspec_t rt) 3038 { 3039 3040 if (!((lt == PTR && is_integer(rt)) || (is_integer(lt) && rt == PTR))) 3041 return false; 3042 3043 const char *lx = lt == PTR ? "pointer" : "integer"; 3044 const char *rx = rt == PTR ? "pointer" : "integer"; 3045 3046 switch (op) { 3047 case INIT: 3048 case RETURN: 3049 /* illegal combination of %s '%s' and %s '%s' for '%s' */ 3050 warning(183, 3051 lx, type_name(ltp), rx, type_name(rtp), op_name(op)); 3052 break; 3053 case FARG: 3054 /* illegal combination of %s '%s' and %s '%s', arg #%d */ 3055 warning(154, 3056 lx, type_name(ltp), rx, type_name(rtp), arg); 3057 break; 3058 default: 3059 /* illegal combination of %s '%s' and %s '%s', op '%s' */ 3060 warning(123, 3061 lx, type_name(ltp), rx, type_name(rtp), op_name(op)); 3062 break; 3063 } 3064 return true; 3065 } 3066 3067 static bool 3068 check_assign_pointer(op_t op, int arg, 3069 const type_t *ltp, tspec_t lt, 3070 const type_t *rtp, tspec_t rt) 3071 { 3072 if (!(lt == PTR && rt == PTR)) 3073 return false; 3074 3075 if (op == FARG) 3076 /* converting '%s' to incompatible '%s' for ... */ 3077 warning(153, type_name(rtp), type_name(ltp), arg); 3078 else 3079 warn_incompatible_pointers(op, ltp, rtp); 3080 return true; 3081 } 3082 3083 static void 3084 warn_assign(op_t op, int arg, 3085 const type_t *ltp, tspec_t lt, 3086 const type_t *rtp, tspec_t rt) 3087 { 3088 switch (op) { 3089 case INIT: 3090 /* cannot initialize '%s' from '%s' */ 3091 error(185, type_name(ltp), type_name(rtp)); 3092 break; 3093 case RETURN: 3094 /* function has return type '%s' but returns '%s' */ 3095 error(211, type_name(ltp), type_name(rtp)); 3096 break; 3097 case FARG: 3098 /* passing '%s' to incompatible '%s', arg #%d */ 3099 warning(155, type_name(rtp), type_name(ltp), arg); 3100 break; 3101 default: 3102 warn_incompatible_types(op, ltp, lt, rtp, rt); 3103 break; 3104 } 3105 } 3106 3107 /* 3108 * Checks type compatibility for ASSIGN, INIT, FARG and RETURN 3109 * and prints warnings/errors if necessary. 3110 * Returns whether the types are (almost) compatible. 3111 */ 3112 static bool 3113 check_assign_types_compatible(op_t op, int arg, 3114 const tnode_t *ln, const tnode_t *rn) 3115 { 3116 tspec_t lt, rt, lst = NO_TSPEC, rst = NO_TSPEC; 3117 type_t *ltp, *rtp, *lstp = NULL, *rstp = NULL; 3118 3119 if ((lt = (ltp = ln->tn_type)->t_tspec) == PTR) 3120 lst = (lstp = ltp->t_subt)->t_tspec; 3121 if ((rt = (rtp = rn->tn_type)->t_tspec) == PTR) 3122 rst = (rstp = rtp->t_subt)->t_tspec; 3123 3124 if (lt == BOOL && is_scalar(rt)) /* C99 6.3.1.2 */ 3125 return true; 3126 3127 if (is_arithmetic(lt) && (is_arithmetic(rt) || rt == BOOL)) 3128 return true; 3129 3130 if (is_struct_or_union(lt) && is_struct_or_union(rt)) 3131 return ltp->u.sou == rtp->u.sou; 3132 3133 if (lt == PTR && is_null_pointer(rn)) { 3134 if (is_integer(rn->tn_type->t_tspec)) 3135 /* implicit conversion from integer 0 to pointer ... */ 3136 query_message(15, type_name(ltp)); 3137 return true; 3138 } 3139 3140 check_assign_void_pointer(op, arg, lt, lst, rt, rst); 3141 3142 if (check_assign_void_pointer_compat(op, arg, 3143 lt, lstp, lst, rn, rtp, rt, rstp, rst)) 3144 return true; 3145 3146 if (check_assign_pointer_integer(op, arg, ltp, lt, rtp, rt)) 3147 return true; 3148 3149 if (check_assign_pointer(op, arg, ltp, lt, rtp, rt)) 3150 return true; 3151 3152 warn_assign(op, arg, ltp, lt, rtp, rt); 3153 return false; 3154 } 3155 3156 static bool 3157 has_side_effect(const tnode_t *tn) /* NOLINT(misc-no-recursion) */ 3158 { 3159 op_t op = tn->tn_op; 3160 3161 if (modtab[op].m_has_side_effect) 3162 return true; 3163 3164 if (op == CVT && tn->tn_type->t_tspec == VOID) 3165 return has_side_effect(tn->u.ops.left); 3166 3167 /* XXX: Why not has_side_effect(tn->u.ops.left) as well? */ 3168 if (op == LOGAND || op == LOGOR) 3169 return has_side_effect(tn->u.ops.right); 3170 3171 /* XXX: Why not has_side_effect(tn->u.ops.left) as well? */ 3172 if (op == QUEST) 3173 return has_side_effect(tn->u.ops.right); 3174 3175 if (op == COLON || op == COMMA) { 3176 return has_side_effect(tn->u.ops.left) || 3177 has_side_effect(tn->u.ops.right); 3178 } 3179 3180 return false; 3181 } 3182 3183 static bool 3184 is_void_cast(const tnode_t *tn) 3185 { 3186 3187 return tn->tn_op == CVT && tn->tn_cast && 3188 tn->tn_type->t_tspec == VOID; 3189 } 3190 3191 static bool 3192 is_local_symbol(const tnode_t *tn) 3193 { 3194 3195 return tn->tn_op == LOAD && 3196 tn->u.ops.left->tn_op == NAME && 3197 tn->u.ops.left->u.sym->s_scl == AUTO; 3198 } 3199 3200 static bool 3201 is_int_constant_zero(const tnode_t *tn) 3202 { 3203 3204 return tn->tn_op == CON && 3205 tn->tn_type->t_tspec == INT && 3206 tn->u.value.u.integer == 0; 3207 } 3208 3209 static void 3210 check_null_effect(const tnode_t *tn) 3211 { 3212 3213 if (hflag && 3214 !has_side_effect(tn) && 3215 !(is_void_cast(tn) && is_local_symbol(tn->u.ops.left)) && 3216 !(is_void_cast(tn) && is_int_constant_zero(tn->u.ops.left))) { 3217 /* expression has null effect */ 3218 warning(129); 3219 } 3220 } 3221 3222 /* 3223 * Check the types for specific operators and type combinations. 3224 * 3225 * At this point, the operands already conform to the type requirements of 3226 * the operator, such as being integer, floating or scalar. 3227 */ 3228 static bool 3229 typeok_op(op_t op, int arg, 3230 const tnode_t *ln, const type_t *ltp, tspec_t lt, 3231 const tnode_t *rn, const type_t *rtp, tspec_t rt) 3232 { 3233 switch (op) { 3234 case ARROW: 3235 return typeok_arrow(lt); 3236 case POINT: 3237 return typeok_point(ln, ltp, lt); 3238 case INCBEF: 3239 case DECBEF: 3240 case INCAFT: 3241 case DECAFT: 3242 return typeok_incdec(op, ln, ltp); 3243 case INDIR: 3244 return typeok_indir(ltp, lt); 3245 case ADDR: 3246 return typeok_address(op, ln, ltp, lt); 3247 case PLUS: 3248 return typeok_plus(op, ltp, lt, rtp, rt); 3249 case MINUS: 3250 return typeok_minus(op, ltp, lt, rtp, rt); 3251 case SHL: 3252 typeok_shl(op, lt, rt); 3253 goto shift; 3254 case SHR: 3255 typeok_shr(op, ln, lt, rn, rt); 3256 shift: 3257 typeok_shift(ltp, lt, rn, rt); 3258 break; 3259 case LT: 3260 case LE: 3261 case GT: 3262 case GE: 3263 compare: 3264 return typeok_compare(op, ln, ltp, lt, rn, rtp, rt); 3265 case EQ: 3266 case NE: 3267 if (is_typeok_eq(ln, lt, rn, rt)) 3268 break; 3269 goto compare; 3270 case QUEST: 3271 return typeok_quest(lt, rn); 3272 case COLON: 3273 return typeok_colon(ln, ltp, lt, rn, rtp, rt); 3274 case ASSIGN: 3275 case INIT: 3276 case FARG: 3277 case RETURN: 3278 if (!check_assign_types_compatible(op, arg, ln, rn)) 3279 return false; 3280 goto assign; 3281 case MULASS: 3282 case DIVASS: 3283 case MODASS: 3284 goto assign; 3285 case ADDASS: 3286 case SUBASS: 3287 if ((lt == PTR && !is_integer(rt)) || rt == PTR) { 3288 warn_incompatible_types(op, ltp, lt, rtp, rt); 3289 return false; 3290 } 3291 goto assign; 3292 case SHLASS: 3293 goto assign; 3294 case SHRASS: 3295 if (pflag && !is_uinteger(lt) && 3296 !(!allow_c90 && is_uinteger(rt))) { 3297 /* bitwise '%s' on signed value possibly nonportable */ 3298 warning(117, op_name(op)); 3299 } 3300 goto assign; 3301 case ANDASS: 3302 case XORASS: 3303 case ORASS: 3304 assign: 3305 return typeok_assign(op, ln, ltp, lt); 3306 case COMMA: 3307 if (!modtab[ln->tn_op].m_has_side_effect) 3308 check_null_effect(ln); 3309 break; 3310 default: 3311 break; 3312 } 3313 return true; 3314 } 3315 3316 static void 3317 check_bad_enum_operation(op_t op, const tnode_t *ln, const tnode_t *rn) 3318 { 3319 3320 if (!eflag) 3321 return; 3322 3323 /* Allow enum in array indices. */ 3324 if (op == PLUS && 3325 ((ln->tn_type->t_is_enum && rn->tn_type->t_tspec == PTR) || 3326 (rn->tn_type->t_is_enum && ln->tn_type->t_tspec == PTR))) { 3327 return; 3328 } 3329 3330 /* dubious operation '%s' on enum */ 3331 warning(241, op_name(op)); 3332 } 3333 3334 static void 3335 check_enum_type_mismatch(op_t op, int arg, const tnode_t *ln, const tnode_t *rn) 3336 { 3337 const mod_t *mp = &modtab[op]; 3338 3339 if (ln->tn_type->u.enumer != rn->tn_type->u.enumer) { 3340 switch (op) { 3341 case INIT: 3342 /* enum type mismatch between '%s' and '%s' in ... */ 3343 warning(210, 3344 type_name(ln->tn_type), type_name(rn->tn_type)); 3345 break; 3346 case FARG: 3347 /* function expects '%s', passing '%s' for arg #%d */ 3348 warning(156, 3349 type_name(ln->tn_type), type_name(rn->tn_type), 3350 arg); 3351 break; 3352 case RETURN: 3353 /* function has return type '%s' but returns '%s' */ 3354 warning(211, 3355 type_name(ln->tn_type), type_name(rn->tn_type)); 3356 break; 3357 default: 3358 /* enum type mismatch: '%s' '%s' '%s' */ 3359 warning(130, type_name(ln->tn_type), op_name(op), 3360 type_name(rn->tn_type)); 3361 break; 3362 } 3363 } else if (Pflag && eflag && mp->m_comparison && op != EQ && op != NE) 3364 /* operator '%s' assumes that '%s' is ordered */ 3365 warning(243, op_name(op), type_name(ln->tn_type)); 3366 } 3367 3368 static void 3369 check_enum_int_mismatch(op_t op, int arg, const tnode_t *ln, const tnode_t *rn) 3370 { 3371 3372 if (!eflag) 3373 return; 3374 3375 switch (op) { 3376 case INIT: 3377 /* 3378 * Initialization with 0 is allowed. Otherwise, all implicit 3379 * initializations would need to be warned upon as well. 3380 */ 3381 if (!rn->tn_type->t_is_enum && rn->tn_op == CON && 3382 is_integer(rn->tn_type->t_tspec) && 3383 rn->u.value.u.integer == 0) { 3384 return; 3385 } 3386 /* initialization of '%s' with '%s' */ 3387 warning(277, type_name(ln->tn_type), type_name(rn->tn_type)); 3388 break; 3389 case FARG: 3390 /* combination of '%s' and '%s', arg #%d */ 3391 warning(278, 3392 type_name(ln->tn_type), type_name(rn->tn_type), arg); 3393 break; 3394 case RETURN: 3395 /* combination of '%s' and '%s' in return */ 3396 warning(279, type_name(ln->tn_type), type_name(rn->tn_type)); 3397 break; 3398 default: 3399 /* combination of '%s' and '%s', op '%s' */ 3400 warning(242, type_name(ln->tn_type), type_name(rn->tn_type), 3401 op_name(op)); 3402 break; 3403 } 3404 } 3405 3406 static void 3407 typeok_enum(op_t op, const mod_t *mp, int arg, 3408 const tnode_t *ln, const type_t *ltp, 3409 const tnode_t *rn, const type_t *rtp) 3410 { 3411 if (mp->m_bad_on_enum && 3412 (ltp->t_is_enum || (mp->m_binary && rtp->t_is_enum))) { 3413 check_bad_enum_operation(op, ln, rn); 3414 } else if (mp->m_valid_on_enum && 3415 (ltp->t_is_enum && rtp != NULL && rtp->t_is_enum)) { 3416 check_enum_type_mismatch(op, arg, ln, rn); 3417 } else if (mp->m_valid_on_enum && 3418 (ltp->t_is_enum || (rtp != NULL && rtp->t_is_enum))) { 3419 check_enum_int_mismatch(op, arg, ln, rn); 3420 } 3421 } 3422 3423 /* Perform most type checks. Return whether the types are ok. */ 3424 bool 3425 typeok(op_t op, int arg, const tnode_t *ln, const tnode_t *rn) 3426 { 3427 3428 const mod_t *mp = &modtab[op]; 3429 3430 type_t *ltp = ln->tn_type; 3431 tspec_t lt = ltp->t_tspec; 3432 3433 type_t *rtp = mp->m_binary ? rn->tn_type : NULL; 3434 tspec_t rt = mp->m_binary ? rtp->t_tspec : NO_TSPEC; 3435 3436 if (Tflag && !typeok_scalar_strict_bool(op, mp, arg, ln, rn)) 3437 return false; 3438 if (!typeok_scalar(op, mp, ltp, lt, rtp, rt)) 3439 return false; 3440 3441 if (!typeok_op(op, arg, ln, ltp, lt, rn, rtp, rt)) 3442 return false; 3443 3444 typeok_enum(op, mp, arg, ln, ltp, rn, rtp); 3445 return true; 3446 } 3447 3448 /* In traditional C, keep unsigned and promote FLOAT to DOUBLE. */ 3449 static tspec_t 3450 promote_trad(tspec_t t) 3451 { 3452 3453 if (t == UCHAR || t == USHORT) 3454 return UINT; 3455 if (t == CHAR || t == SCHAR || t == SHORT) 3456 return INT; 3457 if (t == FLOAT) 3458 return DOUBLE; 3459 if (t == ENUM) 3460 return INT; 3461 return t; 3462 } 3463 3464 /* 3465 * C99 6.3.1.1p2 requires for types with lower rank than int that "If an int 3466 * can represent all the values of the original type, the value is converted 3467 * to an int; otherwise it is converted to an unsigned int", and that "All 3468 * other types are unchanged by the integer promotions". 3469 */ 3470 static tspec_t 3471 promote_c90(const tnode_t *tn, tspec_t t, bool farg) 3472 { 3473 if (tn->tn_type->t_bitfield) { 3474 unsigned int width = tn->tn_type->t_bit_field_width; 3475 unsigned int int_width = size_in_bits(INT); 3476 // XXX: What about _Bool bit-fields, since C99? 3477 if (width < int_width) 3478 return INT; 3479 if (width == int_width) 3480 return is_uinteger(t) ? UINT : INT; 3481 return t; 3482 } 3483 3484 if (t == CHAR || t == SCHAR) 3485 return INT; 3486 if (t == UCHAR) 3487 return size_in_bits(CHAR) < size_in_bits(INT) ? INT : UINT; 3488 if (t == SHORT) 3489 return INT; 3490 if (t == USHORT) 3491 return size_in_bits(SHORT) < size_in_bits(INT) ? INT : UINT; 3492 if (t == ENUM) 3493 return INT; 3494 if (farg && t == FLOAT) 3495 return DOUBLE; 3496 return t; 3497 } 3498 3499 /* 3500 * Performs the "integer promotions" (C99 6.3.1.1p2), which convert small 3501 * integer types to either int or unsigned int. 3502 * 3503 * If allow_c90 is unset or the operand is a function argument with no type 3504 * information (no prototype or variable # of args), converts float to double. 3505 */ 3506 tnode_t * 3507 promote(op_t op, bool farg, tnode_t *tn) 3508 { 3509 3510 const type_t *otp = tn->tn_type; 3511 tspec_t ot = otp->t_tspec; 3512 if (!is_arithmetic(ot)) 3513 return tn; 3514 3515 tspec_t nt = allow_c90 ? promote_c90(tn, ot, farg) : promote_trad(ot); 3516 if (nt == ot) 3517 return tn; 3518 3519 type_t *ntp = expr_dup_type(gettyp(nt)); 3520 ntp->t_tspec = nt; 3521 ntp->t_is_enum = otp->t_is_enum; 3522 if (ntp->t_is_enum) 3523 ntp->u.enumer = otp->u.enumer; 3524 ntp->t_bitfield = otp->t_bitfield; 3525 if (ntp->t_bitfield) { 3526 ntp->t_bit_field_width = otp->t_bit_field_width; 3527 ntp->t_bit_field_offset = otp->t_bit_field_offset; 3528 } 3529 if (ntp->t_bitfield && is_uinteger(ot) && !is_uinteger(nt)) 3530 ntp->t_bit_field_width++; 3531 return convert(op, 0, ntp, tn); 3532 } 3533 3534 static void 3535 check_lossy_floating_to_integer_conversion( 3536 op_t op, int arg, const type_t *tp, const tnode_t *tn) 3537 { 3538 long double x = tn->u.value.u.floating; 3539 integer_constraints ic = ic_any(tp); 3540 if (is_uinteger(tp->t_tspec) 3541 ? x >= ic.umin && x <= ic.umax && x == (uint64_t)x 3542 : x >= ic.smin && x <= ic.smax && x == (int64_t)x) 3543 return; 3544 if (op == FARG) 3545 /* lossy conversion of %Lg to '%s', arg #%d */ 3546 warning(380, x, type_name(tp), arg); 3547 else 3548 /* lossy conversion of %Lg to '%s' */ 3549 warning(381, x, type_name(tp)); 3550 } 3551 3552 static void 3553 convert_integer_from_floating( 3554 op_t op, int arg, const type_t *tp, const tnode_t *tn) 3555 { 3556 3557 if (op == CVT) 3558 /* cast from floating point '%s' to integer '%s' */ 3559 query_message(2, type_name(tn->tn_type), type_name(tp)); 3560 else 3561 /* implicit conversion from floating point '%s' to ... */ 3562 query_message(1, type_name(tn->tn_type), type_name(tp)); 3563 if (tn->tn_op == CON) 3564 check_lossy_floating_to_integer_conversion(op, arg, tp, tn); 3565 } 3566 3567 static bool 3568 should_warn_about_prototype_conversion(tspec_t nt, 3569 tspec_t ot, const tnode_t *ptn) 3570 { 3571 3572 if (nt == ot) 3573 return false; 3574 3575 if (nt == ENUM && ot == INT) 3576 return false; 3577 3578 if (is_floating(nt) != is_floating(ot) || 3579 portable_rank_cmp(nt, ot) != 0) { 3580 /* representation and/or width change */ 3581 if (!is_integer(ot)) 3582 return true; 3583 /* 3584 * XXX: Investigate whether this rule makes sense; see 3585 * tests/usr.bin/xlint/lint1/platform_long.c. 3586 */ 3587 return portable_rank_cmp(ot, INT) > 0; 3588 } 3589 3590 if (!hflag) 3591 return false; 3592 3593 /* 3594 * If the types differ only in sign and the argument has the same 3595 * representation in both types, print no warning. 3596 */ 3597 if (ptn->tn_op == CON && is_integer(nt) && 3598 signed_type(nt) == signed_type(ot) && 3599 !msb(ptn->u.value.u.integer, ot)) 3600 return false; 3601 3602 return true; 3603 } 3604 3605 /* 3606 * Warn if a prototype causes a type conversion that is different from what 3607 * would happen to the same argument in the absence of a prototype. This 3608 * check is intended for code that needs to stay compatible with pre-C90 C. 3609 * 3610 * Errors/warnings about illegal type combinations are already printed 3611 * in check_assign_types_compatible(). 3612 */ 3613 static void 3614 check_prototype_conversion(int arg, tspec_t nt, tspec_t ot, type_t *tp, 3615 tnode_t *tn) 3616 { 3617 3618 if (!is_arithmetic(nt) || !is_arithmetic(ot)) 3619 return; 3620 3621 /* 3622 * If the type of the formal parameter is char/short, a warning would 3623 * be useless, because functions declared the old style can't expect 3624 * char/short arguments. 3625 */ 3626 if (nt == CHAR || nt == SCHAR || nt == UCHAR || 3627 nt == SHORT || nt == USHORT) 3628 return; 3629 3630 tnode_t *ptn = promote(NOOP, true, tn); 3631 ot = ptn->tn_type->t_tspec; 3632 3633 if (should_warn_about_prototype_conversion(nt, ot, ptn)) { 3634 /* argument %d is converted from '%s' to '%s' ... */ 3635 warning(259, arg, type_name(tn->tn_type), type_name(tp)); 3636 } 3637 } 3638 3639 /* 3640 * When converting a large integer type to a small integer type, in some 3641 * cases the value of the actual expression is further restricted than the 3642 * type bounds, such as in (expr & 0xFF) or (expr % 100) or (expr >> 24). 3643 */ 3644 static bool 3645 can_represent(const type_t *tp, const tnode_t *tn) 3646 { 3647 uint64_t nmask = value_bits(width_in_bits(tp)); 3648 if (!is_uinteger(tp->t_tspec)) 3649 nmask >>= 1; 3650 3651 integer_constraints c = ic_expr(tn); 3652 if ((~c.bclr & ~nmask) == 0) 3653 return true; 3654 3655 integer_constraints tpc = ic_any(tp); 3656 if (is_uinteger(tp->t_tspec) 3657 ? tpc.umin <= c.umin && tpc.umax >= c.umax 3658 : tpc.smin <= c.smin && tpc.smax >= c.smax) 3659 return true; 3660 3661 debug_enter(); 3662 debug_step("type '%s' cannot represent:", type_name(tp)); 3663 debug_node(tn); 3664 debug_leave(); 3665 return false; 3666 } 3667 3668 static bool 3669 should_warn_about_integer_conversion(const type_t *ntp, tspec_t nt, 3670 const tnode_t *otn, tspec_t ot) 3671 { 3672 3673 // XXX: The portable_rank_cmp aims at portable mode, independent of the 3674 // current platform, while can_represent acts on the actual type sizes 3675 // from the current platform. This mix is inconsistent, but anything 3676 // else would make the exact conditions too complicated to grasp. 3677 if (aflag > 0 && portable_rank_cmp(nt, ot) < 0) { 3678 if (ot == LONG || ot == ULONG 3679 || ot == LLONG || ot == ULLONG 3680 #ifdef INT128_SIZE 3681 || ot == INT128 || ot == UINT128 3682 #endif 3683 || aflag > 1) 3684 return !can_represent(ntp, otn); 3685 } 3686 return false; 3687 } 3688 3689 static void 3690 convert_integer_from_integer(op_t op, int arg, tspec_t nt, tspec_t ot, 3691 type_t *tp, tnode_t *tn) 3692 { 3693 3694 if (tn->tn_op == CON) 3695 return; 3696 3697 if (op == CVT) 3698 return; 3699 3700 if (Pflag && pflag && aflag > 0 && 3701 portable_rank_cmp(nt, ot) > 0 && 3702 is_uinteger(nt) != is_uinteger(ot)) { 3703 if (op == FARG) 3704 /* conversion to '%s' may sign-extend ... */ 3705 warning(297, type_name(tp), arg); 3706 else 3707 /* conversion to '%s' may sign-extend ... */ 3708 warning(131, type_name(tp)); 3709 } 3710 3711 if (Pflag && portable_rank_cmp(nt, ot) > 0 && 3712 (tn->tn_op == PLUS || tn->tn_op == MINUS || tn->tn_op == MULT || 3713 tn->tn_op == SHL)) { 3714 /* suggest cast from '%s' to '%s' on op '%s' to ... */ 3715 warning(324, type_name(gettyp(ot)), type_name(tp), 3716 op_name(tn->tn_op)); 3717 } 3718 3719 if (should_warn_about_integer_conversion(tp, nt, tn, ot)) { 3720 if (op == FARG) { 3721 /* conversion from '%s' to '%s' may lose ... */ 3722 warning(298, 3723 type_name(tn->tn_type), type_name(tp), arg); 3724 } else { 3725 /* conversion from '%s' to '%s' may lose accuracy */ 3726 warning(132, 3727 type_name(tn->tn_type), type_name(tp)); 3728 } 3729 } 3730 3731 if (is_uinteger(nt) != is_uinteger(ot)) 3732 /* implicit conversion changes sign from '%s' to '%s' */ 3733 query_message(3, type_name(tn->tn_type), type_name(tp)); 3734 } 3735 3736 static void 3737 convert_integer_from_pointer(op_t op, tspec_t nt, type_t *tp, tnode_t *tn) 3738 { 3739 3740 if (tn->tn_op == CON) 3741 return; 3742 if (op != CVT) 3743 return; /* We already got an error. */ 3744 if (portable_rank_cmp(nt, PTR) >= 0) 3745 return; 3746 3747 if (pflag && size_in_bits(nt) >= size_in_bits(PTR)) { 3748 /* conversion of pointer to '%s' may lose bits */ 3749 warning(134, type_name(tp)); 3750 } else { 3751 /* conversion of pointer to '%s' loses bits */ 3752 warning(133, type_name(tp)); 3753 } 3754 } 3755 3756 static bool 3757 struct_starts_with(const type_t *struct_tp, const type_t *member_tp) 3758 { 3759 3760 return struct_tp->u.sou->sou_first_member != NULL && 3761 types_compatible(struct_tp->u.sou->sou_first_member->s_type, 3762 member_tp, true, false, NULL); 3763 } 3764 3765 static bool 3766 is_byte_array(const type_t *tp) 3767 { 3768 3769 return tp->t_tspec == ARRAY && 3770 (tp->t_subt->t_tspec == CHAR || tp->t_subt->t_tspec == UCHAR); 3771 } 3772 3773 static bool 3774 union_contains(const type_t *utp, const type_t *mtp) 3775 { 3776 for (const sym_t *mem = utp->u.sou->sou_first_member; 3777 mem != NULL; mem = mem->s_next) { 3778 if (types_compatible(mem->s_type, mtp, true, false, NULL)) 3779 return true; 3780 } 3781 return false; 3782 } 3783 3784 static bool 3785 should_warn_about_pointer_cast(const type_t *nstp, tspec_t nst, 3786 const type_t *ostp, tspec_t ost) 3787 { 3788 3789 while (nst == ARRAY) 3790 nstp = nstp->t_subt, nst = nstp->t_tspec; 3791 while (ost == ARRAY) 3792 ostp = ostp->t_subt, ost = ostp->t_tspec; 3793 3794 if (nst == STRUCT && ost == STRUCT && 3795 (struct_starts_with(nstp, ostp) || 3796 struct_starts_with(ostp, nstp))) 3797 return false; 3798 3799 if (is_incomplete(nstp) || is_incomplete(ostp)) 3800 return false; 3801 3802 if (nst == CHAR || nst == UCHAR) 3803 return false; /* for the sake of traditional C code */ 3804 if (ost == CHAR || ost == UCHAR) 3805 return false; /* for the sake of traditional C code */ 3806 3807 /* Allow cast between pointers to sockaddr variants. */ 3808 if (nst == STRUCT && ost == STRUCT) { 3809 const sym_t *nmem = nstp->u.sou->sou_first_member; 3810 const sym_t *omem = ostp->u.sou->sou_first_member; 3811 while (nmem != NULL && omem != NULL && 3812 types_compatible(nmem->s_type, omem->s_type, 3813 true, false, NULL)) 3814 nmem = nmem->s_next, omem = omem->s_next; 3815 if (nmem != NULL && is_byte_array(nmem->s_type)) 3816 return false; 3817 if (omem != NULL && is_byte_array(omem->s_type)) 3818 return false; 3819 if (nmem == NULL && omem == NULL) 3820 return false; 3821 } 3822 3823 if (nst == UNION || ost == UNION) { 3824 const type_t *union_tp = nst == UNION ? nstp : ostp; 3825 const type_t *other_tp = nst == UNION ? ostp : nstp; 3826 if (union_contains(union_tp, other_tp)) 3827 return false; 3828 } 3829 3830 if (is_struct_or_union(nst) && is_struct_or_union(ost)) 3831 return nstp->u.sou != ostp->u.sou; 3832 3833 enum rank_kind rk1 = type_properties(nst)->tt_rank_kind; 3834 enum rank_kind rk2 = type_properties(ost)->tt_rank_kind; 3835 if (rk1 != rk2 || rk1 == RK_NONE) 3836 return true; 3837 3838 return portable_rank_cmp(nst, ost) != 0; 3839 } 3840 3841 static void 3842 convert_pointer_from_pointer(type_t *ntp, tnode_t *tn) 3843 { 3844 const type_t *nstp = ntp->t_subt; 3845 const type_t *otp = tn->tn_type; 3846 const type_t *ostp = otp->t_subt; 3847 tspec_t nst = nstp->t_tspec; 3848 tspec_t ost = ostp->t_tspec; 3849 3850 if (nst == VOID || ost == VOID) { 3851 /* TODO: C99 behaves like C90 here. */ 3852 if (!allow_trad && !allow_c99 && (nst == FUNC || ost == FUNC)) { 3853 const char *nts, *ots; 3854 /* null pointers are already handled in convert() */ 3855 *(nst == FUNC ? &nts : &ots) = "function pointer"; 3856 *(nst == VOID ? &nts : &ots) = "'void *'"; 3857 /* conversion of %s to %s requires a cast */ 3858 warning(303, ots, nts); 3859 } 3860 return; 3861 } 3862 if (nst == FUNC && ost == FUNC) 3863 return; 3864 if (nst == FUNC || ost == FUNC) { 3865 /* converting '%s' to '%s' is questionable */ 3866 warning(229, type_name(otp), type_name(ntp)); 3867 return; 3868 } 3869 3870 if (hflag && alignment(nstp) > alignment(ostp) && 3871 ost != CHAR && ost != UCHAR && 3872 !is_incomplete(ostp) && 3873 !(nst == UNION && union_contains(nstp, ostp))) { 3874 /* converting '%s' to '%s' increases alignment ... */ 3875 warning(135, type_name(otp), type_name(ntp), 3876 alignment(ostp), alignment(nstp)); 3877 } 3878 3879 if (cflag && should_warn_about_pointer_cast(nstp, nst, ostp, ost)) { 3880 /* pointer cast from '%s' to unrelated '%s' */ 3881 warning(247, type_name(ostp), type_name(nstp)); 3882 } 3883 } 3884 3885 /* 3886 * Insert a conversion operator, which converts the type of the node 3887 * to another given type. 3888 * 3889 * Possible values for 'op': 3890 * CVT a cast-expression 3891 * binary integer promotion for one of the operands, or a usual 3892 * arithmetic conversion 3893 * binary plain or compound assignments to bit-fields 3894 * FARG 'arg' is the number of the parameter (used for warnings) 3895 * NOOP several other implicit conversions 3896 * ... 3897 */ 3898 tnode_t * 3899 convert(op_t op, int arg, type_t *tp, tnode_t *tn) 3900 { 3901 tspec_t nt = tp->t_tspec; 3902 tspec_t ot = tn->tn_type->t_tspec; 3903 3904 if (allow_trad && allow_c90 && op == FARG) 3905 check_prototype_conversion(arg, nt, ot, tp, tn); 3906 3907 if (nt == BOOL) { 3908 /* No further checks. */ 3909 3910 } else if (is_integer(nt)) { 3911 if (ot == BOOL) { 3912 /* No further checks. */ 3913 } else if (is_integer(ot)) 3914 convert_integer_from_integer(op, arg, nt, ot, tp, tn); 3915 else if (is_floating(ot)) 3916 convert_integer_from_floating(op, arg, tp, tn); 3917 else if (ot == PTR) 3918 convert_integer_from_pointer(op, nt, tp, tn); 3919 3920 } else if (is_floating(nt)) { 3921 if (is_integer(ot) && op != CVT) { 3922 /* implicit conversion from integer '%s' to ... */ 3923 query_message(19, 3924 type_name(tn->tn_type), type_name(tp)); 3925 } 3926 3927 } else if (nt == PTR) { 3928 if (is_null_pointer(tn)) { 3929 /* a null pointer may be assigned to any pointer. */ 3930 } else if (ot == PTR && op == CVT) 3931 convert_pointer_from_pointer(tp, tn); 3932 } 3933 3934 tnode_t *ntn = expr_alloc_tnode(); 3935 ntn->tn_op = CVT; 3936 ntn->tn_type = tp; 3937 ntn->tn_cast = op == CVT; 3938 ntn->tn_sys |= tn->tn_sys; 3939 ntn->u.ops.right = NULL; 3940 if (tn->tn_op != CON || nt == VOID) { 3941 ntn->u.ops.left = tn; 3942 } else { 3943 ntn->tn_op = CON; 3944 convert_constant(op, arg, ntn->tn_type, &ntn->u.value, 3945 &tn->u.value); 3946 } 3947 3948 return ntn; 3949 } 3950 3951 static void 3952 convert_constant_from_floating(op_t op, int arg, const type_t *ntp, 3953 tspec_t nt, val_t *nv, val_t *ov) 3954 { 3955 long double max = 0.0, min = 0.0; 3956 3957 switch (nt) { 3958 case CHAR: 3959 max = TARG_CHAR_MAX; min = TARG_CHAR_MIN; break; 3960 case UCHAR: 3961 max = TARG_UCHAR_MAX; min = 0; break; 3962 case SCHAR: 3963 max = TARG_SCHAR_MAX; min = TARG_SCHAR_MIN; break; 3964 case SHORT: 3965 max = TARG_SHRT_MAX; min = TARG_SHRT_MIN; break; 3966 case USHORT: 3967 max = TARG_USHRT_MAX; min = 0; break; 3968 case ENUM: 3969 case INT: 3970 max = TARG_INT_MAX; min = TARG_INT_MIN; break; 3971 case UINT: 3972 max = TARG_UINT_MAX; min = 0; break; 3973 case LONG: 3974 max = TARG_LONG_MAX; min = TARG_LONG_MIN; break; 3975 case ULONG: 3976 max = TARG_ULONG_MAX; min = 0; break; 3977 case LLONG: 3978 max = LLONG_MAX; min = LLONG_MIN; break; 3979 case ULLONG: 3980 max = ULLONG_MAX; min = 0; break; 3981 case FLOAT: 3982 case FCOMPLEX: 3983 max = FLT_MAX; min = -FLT_MAX; break; 3984 case DOUBLE: 3985 case DCOMPLEX: 3986 max = DBL_MAX; min = -DBL_MAX; break; 3987 case LDOUBLE: 3988 case LCOMPLEX: 3989 /* LINTED 248; see floating_error_value. */ 3990 max = LDBL_MAX; min = -max; break; 3991 default: 3992 lint_assert(/*CONSTCOND*/false); 3993 } 3994 if (ov->u.floating > max || ov->u.floating < min) { 3995 lint_assert(nt != LDOUBLE); 3996 const char *ot_name = type_name(gettyp(ov->v_tspec)); 3997 const char *nt_name = type_name(ntp); 3998 if (is_integer(nt)) 3999 goto after_warning; 4000 if (op == FARG) 4001 /* conversion of '%s' to '%s' is out of range, ... */ 4002 warning(295, ot_name, nt_name, arg); 4003 else 4004 /* conversion of '%s' to '%s' is out of range */ 4005 warning(119, ot_name, nt_name); 4006 after_warning: 4007 ov->u.floating = ov->u.floating > 0 ? max : min; 4008 } 4009 4010 if (nt == FLOAT || nt == FCOMPLEX) 4011 nv->u.floating = (float)ov->u.floating; 4012 else if (nt == DOUBLE || nt == DCOMPLEX) 4013 nv->u.floating = (double)ov->u.floating; 4014 else if (nt == LDOUBLE || nt == LCOMPLEX) 4015 nv->u.floating = ov->u.floating; 4016 else 4017 nv->u.integer = (int64_t)ov->u.floating; 4018 } 4019 4020 static bool 4021 convert_constant_to_floating(tspec_t nt, val_t *nv, 4022 tspec_t ot, const val_t *v) 4023 { 4024 if (nt == FLOAT) { 4025 nv->u.floating = (ot == PTR || is_uinteger(ot)) ? 4026 (float)(uint64_t)v->u.integer : (float)v->u.integer; 4027 } else if (nt == DOUBLE) { 4028 nv->u.floating = (ot == PTR || is_uinteger(ot)) ? 4029 (double)(uint64_t)v->u.integer : (double)v->u.integer; 4030 } else if (nt == LDOUBLE) { 4031 nv->u.floating = (ot == PTR || is_uinteger(ot)) 4032 ? (long double)(uint64_t)v->u.integer 4033 : (long double)v->u.integer; 4034 } else 4035 return false; 4036 return true; 4037 } 4038 4039 static void 4040 warn_constant_truncated(op_t op, const val_t *v) 4041 { 4042 char buf[256]; 4043 bool is_unsigned = is_uinteger(v->v_tspec); 4044 int64_t val = v->u.integer; 4045 unsigned long long abs_val = is_unsigned || val >= 0 4046 ? (unsigned long long)val 4047 : -(unsigned long long)val; 4048 const char *sign = is_unsigned || val >= 0 ? "" : "-"; 4049 snprintf(buf, sizeof(buf), "%s%#llx", sign, abs_val); 4050 /* constant %s truncated by conversion, op '%s' */ 4051 warning(306, buf, op_name(op)); 4052 } 4053 4054 static void 4055 convert_constant_check_range_bitor(size_t nsz, size_t osz, const val_t *v, 4056 uint64_t xmask, op_t op) 4057 { 4058 if (nsz < osz && (v->u.integer & xmask) != 0) 4059 warn_constant_truncated(op, v); 4060 } 4061 4062 static void 4063 convert_constant_check_range_bitand(size_t nsz, size_t osz, 4064 uint64_t xmask, const val_t *nv, 4065 tspec_t ot, const val_t *v, 4066 const type_t *tp, op_t op) 4067 { 4068 if (nsz > osz && 4069 (nv->u.integer & bit((unsigned int)(osz - 1))) != 0 && 4070 (nv->u.integer & xmask) != xmask) { 4071 /* extra bits set to 0 in conversion of '%s' to '%s', ... */ 4072 warning(309, type_name(gettyp(ot)), 4073 type_name(tp), op_name(op)); 4074 } else if (nsz < osz && 4075 (v->u.integer & xmask) != xmask && 4076 (v->u.integer & xmask) != 0) 4077 warn_constant_truncated(op, v); 4078 } 4079 4080 static void 4081 convert_constant_check_range_signed(op_t op, int arg, 4082 const type_t *ntp, int64_t ov) 4083 { 4084 if (op == ASSIGN) 4085 /* assignment of negative constant %lld to unsigned ... */ 4086 warning(164, (long long)ov, type_name(ntp)); 4087 else if (op == INIT) 4088 /* initialization of unsigned type '%s' with negative ... */ 4089 warning(221, type_name(ntp), (long long)ov); 4090 else if (op == FARG) 4091 /* conversion of negative constant %lld to unsigned ... */ 4092 warning(296, (long long)ov, type_name(ntp), arg); 4093 else if (modtab[op].m_comparison) { 4094 /* handled by check_integer_comparison() */ 4095 } else 4096 /* conversion of negative constant %lld to unsigned ... */ 4097 warning(222, (long long)ov, type_name(ntp)); 4098 } 4099 4100 /* 4101 * Loss of significant bit(s). All truncated bits of unsigned types or all 4102 * truncated bits plus the msb of the target for signed types are considered 4103 * to be significant bits. Loss of significant bits means that at least one 4104 * of the bits was set in an unsigned type or that at least one but not all 4105 * of the bits was set in a signed type. Loss of significant bits means that 4106 * it is not possible, also not with necessary casts, to convert back to the 4107 * original type. An example for a necessary cast is: 4108 * char c; int i; c = 128; 4109 * i = c; ** yields -128 ** 4110 * i = (unsigned char)c; ** yields 128 ** 4111 */ 4112 static void 4113 warn_constant_check_range_truncated(op_t op, int arg, const type_t *tp, 4114 tspec_t ot) 4115 { 4116 if (op == ASSIGN && tp->t_bitfield) 4117 /* precision lost in bit-field assignment */ 4118 warning(166); 4119 else if (op == ASSIGN) 4120 /* constant truncated by assignment */ 4121 warning(165); 4122 else if (op == INIT && tp->t_bitfield) 4123 /* bit-field initializer does not fit */ 4124 warning(180); 4125 else if (op == INIT) 4126 /* initializer does not fit */ 4127 warning(178); 4128 else if (op == CASE) 4129 /* case label is converted from '%s' to '%s' */ 4130 warning(196, tspec_name(ot), type_name(tp)); 4131 else if (op == FARG) 4132 /* conversion of '%s' to '%s' is out of range, arg #%d */ 4133 warning(295, type_name(gettyp(ot)), type_name(tp), arg); 4134 else 4135 /* conversion of '%s' to '%s' is out of range */ 4136 warning(119, type_name(gettyp(ot)), type_name(tp)); 4137 } 4138 4139 static void 4140 warn_constant_check_range_loss(op_t op, int arg, const type_t *tp, 4141 tspec_t ot) 4142 { 4143 if (op == ASSIGN && tp->t_bitfield) 4144 /* precision lost in bit-field assignment */ 4145 warning(166); 4146 else if (op == INIT && tp->t_bitfield) 4147 /* bit-field initializer out of range */ 4148 warning(11); 4149 else if (op == CASE) 4150 /* case label is converted from '%s' to '%s' */ 4151 warning(196, tspec_name(ot), type_name(tp)); 4152 else if (op == FARG) 4153 /* conversion of '%s' to '%s' is out of range, arg #%d */ 4154 warning(295, type_name(gettyp(ot)), type_name(tp), arg); 4155 else 4156 /* conversion of '%s' to '%s' is out of range */ 4157 warning(119, type_name(gettyp(ot)), type_name(tp)); 4158 } 4159 4160 static void 4161 convert_constant_check_range(tspec_t ot, const type_t *tp, tspec_t nt, 4162 op_t op, int arg, const val_t *v, val_t *nv) 4163 { 4164 unsigned int obitsz, nbitsz; 4165 uint64_t xmask, xmsk1; 4166 4167 obitsz = size_in_bits(ot); 4168 nbitsz = tp->t_bitfield ? tp->t_bit_field_width : size_in_bits(nt); 4169 xmask = value_bits(nbitsz) ^ value_bits(obitsz); 4170 xmsk1 = value_bits(nbitsz) ^ value_bits(obitsz - 1); 4171 if (op == ORASS || op == BITOR || op == BITXOR) { 4172 convert_constant_check_range_bitor( 4173 nbitsz, obitsz, v, xmask, op); 4174 } else if (op == ANDASS || op == BITAND) { 4175 convert_constant_check_range_bitand( 4176 nbitsz, obitsz, xmask, nv, ot, v, tp, op); 4177 } else if (nt != PTR && is_uinteger(nt) && 4178 ot != PTR && !is_uinteger(ot) && 4179 v->u.integer < 0) 4180 convert_constant_check_range_signed(op, arg, 4181 tp, v->u.integer); 4182 else if (nv->u.integer != v->u.integer && nbitsz <= obitsz && 4183 (v->u.integer & xmask) != 0 && 4184 (is_uinteger(ot) || (v->u.integer & xmsk1) != xmsk1)) 4185 warn_constant_check_range_truncated(op, arg, tp, ot); 4186 else if (nv->u.integer != v->u.integer) 4187 warn_constant_check_range_loss(op, arg, tp, ot); 4188 } 4189 4190 /* Converts a typed constant to a constant of another type. */ 4191 void 4192 convert_constant(op_t op, int arg, const type_t *ntp, val_t *nv, val_t *ov) 4193 { 4194 /* 4195 * TODO: make 'ov' const; the name of this function does not suggest 4196 * that it modifies 'ov'. 4197 */ 4198 tspec_t ot = ov->v_tspec; 4199 tspec_t nt = nv->v_tspec = ntp->t_tspec; 4200 bool range_check = false; 4201 4202 if (nt == BOOL) { /* C99 6.3.1.2 */ 4203 nv->v_unsigned_since_c90 = false; 4204 nv->u.integer = is_nonzero_val(ov) ? 1 : 0; 4205 return; 4206 } 4207 4208 if (ot == FLOAT || ot == DOUBLE || ot == LDOUBLE) 4209 convert_constant_from_floating(op, arg, ntp, nt, nv, ov); 4210 else if (!convert_constant_to_floating(nt, nv, ot, ov)) { 4211 range_check = true; /* Check for lost precision. */ 4212 nv->u.integer = ov->u.integer; 4213 } 4214 4215 if (allow_trad && allow_c90 && ov->v_unsigned_since_c90 && 4216 (is_floating(nt) || ( 4217 (is_integer(nt) && !is_uinteger(nt) && 4218 portable_rank_cmp(nt, ot) > 0)))) { 4219 /* C90 treats constant as unsigned */ 4220 warning(157); 4221 ov->v_unsigned_since_c90 = false; 4222 } 4223 4224 if (is_integer(nt)) { 4225 unsigned int size = ntp->t_bitfield 4226 ? ntp->t_bit_field_width : size_in_bits(nt); 4227 nv->u.integer = convert_integer(nv->u.integer, nt, size); 4228 } 4229 4230 if (range_check && op != CVT) 4231 convert_constant_check_range(ot, ntp, nt, op, arg, ov, nv); 4232 } 4233 4234 tnode_t * 4235 build_sizeof(const type_t *tp) 4236 { 4237 unsigned int size_in_bytes = type_size_in_bits(tp) / CHAR_SIZE; 4238 tnode_t *tn = build_integer_constant(SIZEOF_TSPEC, size_in_bytes); 4239 tn->tn_system_dependent = true; 4240 debug_step("build_sizeof '%s' = %u", type_name(tp), size_in_bytes); 4241 return tn; 4242 } 4243 4244 tnode_t * 4245 build_offsetof(const type_t *tp, designation dn) 4246 { 4247 unsigned int offset_in_bits = 0; 4248 4249 if (!is_struct_or_union(tp->t_tspec)) { 4250 /* unacceptable operand of '%s' */ 4251 error(111, "offsetof"); 4252 goto proceed; 4253 } 4254 for (size_t i = 0; i < dn.dn_len; i++) { 4255 const designator *dr = dn.dn_items + i; 4256 if (dr->dr_kind == DK_SUBSCRIPT) { 4257 if (tp->t_tspec != ARRAY) 4258 goto proceed; /* silent error */ 4259 tp = tp->t_subt; 4260 offset_in_bits += (unsigned)dr->dr_subscript 4261 * type_size_in_bits(tp); 4262 } else { 4263 if (!is_struct_or_union(tp->t_tspec)) 4264 goto proceed; /* silent error */ 4265 const char *name = dr->dr_member->s_name; 4266 sym_t *mem = find_member(tp->u.sou, name); 4267 if (mem == NULL) { 4268 /* type '%s' does not have member '%s' */ 4269 error(101, name, type_name(tp)); 4270 goto proceed; 4271 } 4272 tp = mem->s_type; 4273 offset_in_bits += mem->u.s_member.sm_offset_in_bits; 4274 } 4275 } 4276 free(dn.dn_items); 4277 4278 proceed:; 4279 unsigned int offset_in_bytes = offset_in_bits / CHAR_SIZE; 4280 tnode_t *tn = build_integer_constant(SIZEOF_TSPEC, offset_in_bytes); 4281 tn->tn_system_dependent = true; 4282 return tn; 4283 } 4284 4285 unsigned int 4286 type_size_in_bits(const type_t *tp) 4287 { 4288 4289 unsigned int elem = 1; 4290 bool flex = false; 4291 lint_assert(tp != NULL); 4292 while (tp->t_tspec == ARRAY) { 4293 flex = true; /* allow c99 flex arrays [] [0] */ 4294 elem *= tp->u.dimension; 4295 tp = tp->t_subt; 4296 } 4297 if (elem == 0 && !flex) { 4298 /* cannot take size/alignment of incomplete type */ 4299 error(143); 4300 elem = 1; 4301 } 4302 4303 unsigned int elsz; 4304 switch (tp->t_tspec) { 4305 case VOID: 4306 /* cannot take size/alignment of void */ 4307 error(146); 4308 elsz = 1; 4309 break; 4310 case FUNC: 4311 /* cannot take size/alignment of function type '%s' */ 4312 error(144, type_name(tp)); 4313 elsz = 1; 4314 break; 4315 case STRUCT: 4316 case UNION: 4317 if (is_incomplete(tp)) { 4318 /* cannot take size/alignment of incomplete type */ 4319 error(143); 4320 elsz = 1; 4321 } else 4322 elsz = tp->u.sou->sou_size_in_bits; 4323 break; 4324 case ENUM: 4325 if (is_incomplete(tp)) { 4326 /* cannot take size/alignment of incomplete type */ 4327 warning(143); 4328 } 4329 /* FALLTHROUGH */ 4330 default: 4331 if (tp->t_bitfield) 4332 /* cannot take size/alignment of bit-field */ 4333 error(145); 4334 elsz = size_in_bits(tp->t_tspec); 4335 lint_assert(elsz > 0); 4336 break; 4337 } 4338 4339 return elem * elsz; 4340 } 4341 4342 /* C11 6.5.3.4, GCC */ 4343 tnode_t * 4344 build_alignof(const type_t *tp) 4345 { 4346 if (tp->t_tspec == FUNC) { 4347 /* cannot take size/alignment of function type '%s' */ 4348 error(144, type_name(tp)); 4349 return NULL; 4350 } 4351 if (tp->t_tspec == VOID) { 4352 /* cannot take size/alignment of void */ 4353 error(146); 4354 return NULL; 4355 } 4356 if (is_incomplete(tp)) { 4357 /* cannot take size/alignment of incomplete type */ 4358 error(143); 4359 return NULL; 4360 } 4361 if (tp->t_bitfield) { 4362 /* cannot take size/alignment of bit-field */ 4363 error(145); 4364 return NULL; 4365 } 4366 return build_integer_constant(SIZEOF_TSPEC, (int64_t)alignment(tp)); 4367 } 4368 4369 static tnode_t * 4370 cast_to_union(tnode_t *otn, bool sys, type_t *ntp) 4371 { 4372 4373 if (!allow_gcc) { 4374 /* union cast is a GCC extension */ 4375 error(328); 4376 return NULL; 4377 } 4378 4379 for (const sym_t *m = ntp->u.sou->sou_first_member; 4380 m != NULL; m = m->s_next) { 4381 if (types_compatible(m->s_type, otn->tn_type, 4382 false, false, NULL)) { 4383 tnode_t *ntn = build_op(CVT, sys, ntp, otn, NULL); 4384 ntn->tn_cast = true; 4385 return ntn; 4386 } 4387 } 4388 4389 /* type '%s' is not a member of '%s' */ 4390 error(329, type_name(otn->tn_type), type_name(ntp)); 4391 return NULL; 4392 } 4393 4394 // In GCC mode, allow 'nullptr + offset' as a constant expression. 4395 static tnode_t * 4396 null_pointer_offset(tnode_t *tn) 4397 { 4398 uint64_t off = 0; 4399 const tnode_t *n = tn; 4400 while ((n->tn_op == PLUS || n->tn_op == MINUS) 4401 && is_integer(n->u.ops.right->tn_type->t_tspec)) { 4402 off += (uint64_t)n->u.ops.right->u.value.u.integer; 4403 n = n->u.ops.left; 4404 } 4405 if (n->tn_type->t_tspec == PTR 4406 && n->tn_op == ADDR 4407 && n->u.ops.left->tn_op == INDIR 4408 && n->u.ops.left->u.ops.left->tn_op == CON 4409 && n->u.ops.left->u.ops.left->tn_type->t_tspec == PTR) { 4410 off += (uint64_t)n->u.ops.left->u.ops.left->u.value.u.integer; 4411 return build_integer_constant(SIZEOF_TSPEC, (int64_t)off); 4412 } 4413 return tn; 4414 } 4415 4416 tnode_t * 4417 cast(tnode_t *tn, bool sys, type_t *tp) 4418 { 4419 4420 if (tn == NULL) 4421 return NULL; 4422 4423 tn = cconv(tn); 4424 4425 lint_assert(tp != NULL); 4426 tspec_t nt = tp->t_tspec; 4427 tspec_t ot = tn->tn_type->t_tspec; 4428 4429 if (nt == VOID) { 4430 /* 4431 * C90 6.3.4, C99 6.5.4p2 and C11 6.5.4p2 allow any type to be 4432 * cast to void. The only other allowed casts are from a 4433 * scalar type to a scalar type. 4434 */ 4435 } else if (nt == UNION) 4436 return cast_to_union(tn, sys, tp); 4437 else if (nt == STRUCT || nt == ARRAY || nt == FUNC) { 4438 /* Casting to a struct is an undocumented GCC extension. */ 4439 if (!(allow_gcc && nt == STRUCT)) 4440 goto invalid_cast; 4441 } else if (is_struct_or_union(ot)) 4442 goto invalid_cast; 4443 else if (ot == VOID) { 4444 /* improper cast of void expression */ 4445 error(148); 4446 return NULL; 4447 } else if (is_integer(nt) && is_scalar(ot)) { 4448 tn = null_pointer_offset(tn); 4449 } else if (is_floating(nt) && is_arithmetic(ot)) { 4450 /* ok */ 4451 } else if (nt == PTR && is_integer(ot)) { 4452 /* ok */ 4453 } else if (nt == PTR && ot == PTR) { 4454 if (!tp->t_subt->t_const && tn->tn_type->t_subt->t_const) { 4455 if (hflag) 4456 /* cast discards 'const' from type '%s' */ 4457 warning(275, type_name(tn->tn_type)); 4458 } 4459 } else 4460 goto invalid_cast; 4461 4462 if (any_query_enabled 4463 && types_compatible(tp, tn->tn_type, false, false, NULL)) 4464 /* no-op cast from '%s' to '%s' */ 4465 query_message(6, type_name(tn->tn_type), type_name(tp)); 4466 4467 tn = convert(CVT, 0, tp, tn); 4468 tn->tn_cast = true; 4469 tn->tn_sys = sys; 4470 4471 return tn; 4472 4473 invalid_cast: 4474 /* invalid cast from '%s' to '%s' */ 4475 error(147, type_name(tn->tn_type), type_name(tp)); 4476 return NULL; 4477 } 4478 4479 void 4480 add_function_argument(function_call *call, tnode_t *arg) 4481 { 4482 /* 4483 * If there was a serious error in the expression for the argument, 4484 * create a dummy argument so the positions of the remaining arguments 4485 * will not change. 4486 */ 4487 if (arg == NULL) 4488 arg = build_integer_constant(INT, 0); 4489 4490 if (call->args_len >= call->args_cap) { 4491 call->args_cap += 8; 4492 tnode_t **new_args = expr_zero_alloc( 4493 call->args_cap * sizeof(*call->args), "tnode*[]"); 4494 if (call->args_len > 0) 4495 memcpy(new_args, call->args, 4496 call->args_len * sizeof(*call->args)); 4497 call->args = new_args; 4498 } 4499 call->args[call->args_len++] = arg; 4500 } 4501 4502 /* 4503 * Compare the type of an argument with the corresponding type of a 4504 * prototype parameter. If it is a valid combination, but both types 4505 * are not the same, insert a conversion to convert the argument into 4506 * the type of the parameter. 4507 */ 4508 static tnode_t * 4509 check_prototype_argument( 4510 int n, /* pos of arg */ 4511 type_t *tp, /* expected type (from prototype) */ 4512 tnode_t *tn) /* argument */ 4513 { 4514 tnode_t *ln = xcalloc(1, sizeof(*ln)); 4515 ln->tn_type = expr_unqualified_type(tp); 4516 ln->tn_lvalue = true; 4517 if (typeok(FARG, n, ln, tn)) { 4518 bool dowarn; 4519 if (!types_compatible(tp, tn->tn_type, 4520 true, false, (dowarn = false, &dowarn)) || dowarn) 4521 tn = convert(FARG, n, tp, tn); 4522 } 4523 free(ln); 4524 return tn; 4525 } 4526 4527 /* 4528 * Check types of all function arguments and insert conversions, 4529 * if necessary. 4530 */ 4531 static void 4532 check_function_arguments(const function_call *call) 4533 { 4534 type_t *ftp = call->func->tn_type->t_subt; 4535 4536 /* get # of parameters in the prototype */ 4537 int npar = 0; 4538 for (const sym_t *p = ftp->u.params; p != NULL; p = p->s_next) 4539 npar++; 4540 4541 int narg = (int)call->args_len; 4542 4543 const sym_t *param = ftp->u.params; 4544 if (ftp->t_proto && npar != narg && !(ftp->t_vararg && npar < narg)) { 4545 /* argument mismatch: %d %s passed, %d expected */ 4546 error(150, narg, narg != 1 ? "arguments" : "argument", npar); 4547 param = NULL; 4548 } 4549 4550 for (int i = 0; i < narg; i++) { 4551 tnode_t *arg = call->args[i]; 4552 4553 /* some things which are always not allowed */ 4554 tspec_t at = arg->tn_type->t_tspec; 4555 if (at == VOID) { 4556 /* void expressions may not be arguments, arg #%d */ 4557 error(151, i + 1); 4558 return; 4559 } 4560 if (is_struct_or_union(at) && is_incomplete(arg->tn_type)) { 4561 /* argument cannot have unknown size, arg #%d */ 4562 error(152, i + 1); 4563 return; 4564 } 4565 if (is_integer(at) && 4566 arg->tn_type->t_is_enum && 4567 is_incomplete(arg->tn_type)) { 4568 /* argument cannot have unknown size, arg #%d */ 4569 warning(152, i + 1); 4570 } 4571 4572 arg = cconv(arg); 4573 call->args[i] = arg; 4574 4575 arg = param != NULL 4576 ? check_prototype_argument(i + 1, param->s_type, arg) 4577 : promote(NOOP, true, arg); 4578 call->args[i] = arg; 4579 4580 if (param != NULL) 4581 param = param->s_next; 4582 } 4583 } 4584 4585 tnode_t * 4586 build_function_call(tnode_t *func, bool sys, function_call *call) 4587 { 4588 4589 if (func == NULL) 4590 return NULL; 4591 4592 call->func = func; 4593 check_ctype_function_call(call); 4594 4595 func = cconv(func); 4596 call->func = func; 4597 4598 if (func->tn_type->t_tspec != PTR || 4599 func->tn_type->t_subt->t_tspec != FUNC) { 4600 /* cannot call '%s', must be a function */ 4601 error(149, type_name(func->tn_type)); 4602 return NULL; 4603 } 4604 4605 check_function_arguments(call); 4606 4607 tnode_t *ntn = expr_alloc_tnode(); 4608 ntn->tn_op = CALL; 4609 ntn->tn_type = func->tn_type->t_subt->t_subt; 4610 ntn->tn_sys = sys; 4611 ntn->u.call = call; 4612 return ntn; 4613 } 4614 4615 /* 4616 * Return the value of an integral constant expression. 4617 * If the expression is not constant or its type is not an integer 4618 * type, an error message is printed. 4619 */ 4620 val_t * 4621 integer_constant(tnode_t *tn, bool required) 4622 { 4623 4624 if (tn != NULL) 4625 tn = cconv(tn); 4626 if (tn != NULL) 4627 tn = promote(NOOP, false, tn); 4628 4629 val_t *v = xcalloc(1, sizeof(*v)); 4630 4631 if (tn == NULL) { 4632 lint_assert(seen_error); 4633 debug_step("constant node is null; returning 1 instead"); 4634 v->v_tspec = INT; 4635 v->u.integer = 1; 4636 return v; 4637 } 4638 4639 v->v_tspec = tn->tn_type->t_tspec; 4640 4641 if (tn->tn_op == CON) { 4642 lint_assert(tn->tn_type->t_tspec == tn->u.value.v_tspec); 4643 if (is_integer(tn->u.value.v_tspec)) { 4644 v->v_unsigned_since_c90 = 4645 tn->u.value.v_unsigned_since_c90; 4646 v->u.integer = tn->u.value.u.integer; 4647 return v; 4648 } 4649 v->u.integer = (int64_t)tn->u.value.u.floating; 4650 } else 4651 v->u.integer = 1; 4652 4653 if (required) 4654 /* integral constant expression expected */ 4655 error(55); 4656 else 4657 /* variable array dimension is a C99/GCC extension */ 4658 c99ism(318); 4659 4660 if (!is_integer(v->v_tspec)) 4661 v->v_tspec = INT; 4662 4663 return v; 4664 } 4665 4666 static bool 4667 is_constcond_false(const tnode_t *tn, tspec_t t) 4668 { 4669 return (t == BOOL || t == INT) && 4670 tn->tn_op == CON && tn->u.value.u.integer == 0; 4671 } 4672 4673 /* 4674 * Perform some tests on expressions which can't be done in build_binary() 4675 * and functions called by build_binary(). These tests must be done here 4676 * because we need some information about the context in which the operations 4677 * are performed. 4678 * After all tests are performed and dofreeblk is true, expr() frees the 4679 * memory which is used for the expression. 4680 */ 4681 void 4682 expr(tnode_t *tn, bool vctx, bool cond, bool dofreeblk, bool is_do_while, 4683 const char *stmt_kind) 4684 { 4685 4686 if (tn == NULL) { /* in case of errors */ 4687 expr_free_all(); 4688 return; 4689 } 4690 4691 /* expr() is also called in global initializations */ 4692 if (dcs->d_kind != DLK_EXTERN && !is_do_while) 4693 check_statement_reachable(stmt_kind); 4694 4695 check_expr_misc(tn, vctx, cond, !cond, false, false, false); 4696 if (tn->tn_op == ASSIGN && !tn->tn_parenthesized) { 4697 if (hflag && cond) 4698 /* assignment in conditional context */ 4699 warning(159); 4700 } else if (tn->tn_op == CON) { 4701 if (hflag && cond && !suppress_constcond && 4702 !tn->tn_system_dependent && 4703 !(is_do_while && 4704 is_constcond_false(tn, tn->tn_type->t_tspec))) 4705 /* constant in conditional context */ 4706 warning(161); 4707 } 4708 if (!modtab[tn->tn_op].m_has_side_effect) { 4709 /* 4710 * for left operands of COMMA this warning is already printed 4711 */ 4712 if (tn->tn_op != COMMA && !vctx && !cond) 4713 check_null_effect(tn); 4714 } 4715 debug_node(tn); 4716 4717 if (dofreeblk) 4718 expr_free_all(); 4719 } 4720 4721 /* If the expression has the form '*(arr + idx)', check the array index. */ 4722 static void 4723 check_array_index(const tnode_t *indir, bool taking_address) 4724 { 4725 const tnode_t *plus, *arr, *idx; 4726 4727 if (indir->tn_op == INDIR 4728 && (plus = indir->u.ops.left, plus->tn_op == PLUS) 4729 && plus->u.ops.left->tn_op == ADDR 4730 && (arr = plus->u.ops.left->u.ops.left, true) 4731 && (arr->tn_op == STRING || arr->tn_op == NAME) 4732 && arr->tn_type->t_tspec == ARRAY 4733 && (idx = plus->u.ops.right, idx->tn_op == CON) 4734 && (!is_incomplete(arr->tn_type) || idx->u.value.u.integer < 0)) 4735 goto proceed; 4736 return; 4737 4738 proceed:; 4739 int elsz = length_in_bits(arr->tn_type->t_subt, NULL); 4740 if (elsz == 0) 4741 return; 4742 elsz /= CHAR_SIZE; 4743 4744 /* Change the unit of the index from bytes to element size. */ 4745 int64_t con = is_uinteger(idx->tn_type->t_tspec) 4746 ? (int64_t)((uint64_t)idx->u.value.u.integer / elsz) 4747 : idx->u.value.u.integer / elsz; 4748 4749 int dim = arr->tn_type->u.dimension + (taking_address ? 1 : 0); 4750 4751 if (!is_uinteger(idx->tn_type->t_tspec) && con < 0) 4752 /* array subscript %jd cannot be negative */ 4753 warning(167, (intmax_t)con); 4754 else if (dim > 0 && (uint64_t)con >= (uint64_t)dim) 4755 /* array subscript %ju cannot be > %d */ 4756 warning(168, (uintmax_t)con, dim - 1); 4757 } 4758 4759 static void 4760 check_expr_addr(const tnode_t *ln, bool szof, bool fcall) 4761 { 4762 /* XXX: Taking warn_about_unreachable into account here feels wrong. */ 4763 if (ln->tn_op == NAME && (reached || !warn_about_unreachable)) { 4764 if (!szof) 4765 mark_as_set(ln->u.sym); 4766 mark_as_used(ln->u.sym, fcall, szof); 4767 } 4768 check_array_index(ln, true); 4769 } 4770 4771 /* 4772 * If there is an asm statement in one of the compound statements around, 4773 * there may be other side effects, so don't warn. 4774 */ 4775 static bool 4776 is_asm_around(void) 4777 { 4778 for (decl_level *dl = dcs; dl != NULL; dl = dl->d_enclosing) 4779 if (dl->d_asm) 4780 return true; 4781 return false; 4782 } 4783 4784 static void 4785 check_expr_side_effect(const tnode_t *ln, bool szof) 4786 { 4787 4788 /* XXX: Taking warn_about_unreachable into account here feels wrong. */ 4789 if (ln->tn_op == NAME && (reached || !warn_about_unreachable)) { 4790 scl_t sc = ln->u.sym->s_scl; 4791 if (sc != EXTERN && sc != STATIC && 4792 !ln->u.sym->s_set && !szof && !is_asm_around()) { 4793 /* '%s' may be used before set */ 4794 warning(158, ln->u.sym->s_name); 4795 mark_as_set(ln->u.sym); 4796 } 4797 mark_as_used(ln->u.sym, false, false); 4798 } 4799 } 4800 4801 static void 4802 check_expr_assign(const tnode_t *ln, bool szof) 4803 { 4804 /* XXX: Taking warn_about_unreachable into account here feels wrong. */ 4805 if (ln->tn_op == NAME && !szof && (reached || !warn_about_unreachable)) { 4806 mark_as_set(ln->u.sym); 4807 if (ln->u.sym->s_scl == EXTERN) 4808 outusg(ln->u.sym); 4809 } 4810 check_array_index(ln, false); 4811 } 4812 4813 static void 4814 check_expr_call(const tnode_t *tn, const tnode_t *ln, 4815 bool szof, bool vctx, bool cond, bool retval_discarded) 4816 { 4817 lint_assert(ln->tn_op == ADDR); 4818 lint_assert(ln->u.ops.left->tn_op == NAME); 4819 if (!szof && !is_compiler_builtin(ln->u.ops.left->u.sym->s_name)) 4820 outcall(tn, vctx || cond, retval_discarded); 4821 4822 const function_call *call = tn->u.call; 4823 if (call->args_len == 4 || call->args_len == 5) 4824 check_snprintb(call); 4825 } 4826 4827 static void 4828 check_expr_op(op_t op, const tnode_t *ln, bool szof, bool fcall, bool eqwarn) 4829 { 4830 switch (op) { 4831 case ADDR: 4832 check_expr_addr(ln, szof, fcall); 4833 break; 4834 case LOAD: 4835 check_array_index(ln, false); 4836 /* FALLTHROUGH */ 4837 case INCBEF: 4838 case DECBEF: 4839 case INCAFT: 4840 case DECAFT: 4841 case ADDASS: 4842 case SUBASS: 4843 case MULASS: 4844 case DIVASS: 4845 case MODASS: 4846 case ANDASS: 4847 case ORASS: 4848 case XORASS: 4849 case SHLASS: 4850 case SHRASS: 4851 case REAL: 4852 case IMAG: 4853 check_expr_side_effect(ln, szof); 4854 break; 4855 case ASSIGN: 4856 check_expr_assign(ln, szof); 4857 break; 4858 case EQ: 4859 if (hflag && eqwarn) 4860 /* operator '==' found where '=' was expected */ 4861 warning(160); 4862 break; 4863 default: 4864 break; 4865 } 4866 } 4867 4868 /* 4869 * vctx ??? 4870 * cond whether the expression is a condition that 4871 * will be compared with 0 4872 * eqwarn whether the operator '==' might be a 4873 * misspelled '=' 4874 * fcall whether the expression is a function call 4875 * retval_discarded whether the return value of a function call 4876 * is discarded; such calls will be analyzed by 4877 * lint2 in messages 4, 8 and 9 4878 * szof whether the expression is part of a sizeof 4879 * expression, which means that its value is 4880 * discarded since only the type is relevant 4881 */ 4882 void 4883 check_expr_misc(const tnode_t *tn, bool vctx, bool cond, 4884 bool eqwarn, bool fcall, bool retval_discarded, bool szof) 4885 { 4886 4887 if (tn == NULL) 4888 return; 4889 op_t op = tn->tn_op; 4890 if (op == NAME || op == CON || op == STRING) 4891 return; 4892 bool is_direct = op == CALL 4893 && tn->u.call->func->tn_op == ADDR 4894 && tn->u.call->func->u.ops.left->tn_op == NAME; 4895 if (op == CALL) { 4896 const function_call *call = tn->u.call; 4897 if (is_direct) 4898 check_expr_call(tn, call->func, 4899 szof, vctx, cond, retval_discarded); 4900 bool discard = op == CVT && tn->tn_type->t_tspec == VOID; 4901 check_expr_misc(call->func, false, false, false, is_direct, 4902 discard, szof); 4903 for (size_t i = 0, n = call->args_len; i < n; i++) 4904 check_expr_misc(call->args[i], 4905 true, false, false, false, false, szof); 4906 return; 4907 } 4908 4909 lint_assert(has_operands(tn)); 4910 tnode_t *ln = tn->u.ops.left; 4911 tnode_t *rn = tn->u.ops.right; 4912 check_expr_op(op, ln, szof, fcall, eqwarn); 4913 4914 const mod_t *mp = &modtab[op]; 4915 bool cvctx = mp->m_value_context; 4916 bool ccond = mp->m_compares_with_zero; 4917 bool eq = mp->m_warn_if_operand_eq && 4918 !ln->tn_parenthesized && 4919 rn != NULL && !rn->tn_parenthesized; 4920 4921 /* 4922 * Values of operands of ':' are not used if the type of at least 4923 * one of the operands (for GCC compatibility) is 'void'. 4924 * 4925 * XXX test/value context of QUEST should probably be used as 4926 * context for both operands of COLON. 4927 */ 4928 if (op == COLON && tn->tn_type->t_tspec == VOID) 4929 cvctx = ccond = false; 4930 bool discard = op == CVT && tn->tn_type->t_tspec == VOID; 4931 check_expr_misc(ln, cvctx, ccond, eq, is_direct, discard, szof); 4932 4933 switch (op) { 4934 case LOGAND: 4935 case LOGOR: 4936 check_expr_misc(rn, false, true, eq, false, false, szof); 4937 break; 4938 case COLON: 4939 check_expr_misc(rn, cvctx, ccond, eq, false, false, szof); 4940 break; 4941 case COMMA: 4942 check_expr_misc(rn, vctx, cond, false, false, false, szof); 4943 break; 4944 default: 4945 if (mp->m_binary) 4946 check_expr_misc(rn, true, false, eq, false, false, 4947 szof); 4948 break; 4949 } 4950 } 4951 4952 /* 4953 * Return whether the expression can be used for static initialization. 4954 * 4955 * Constant initialization expressions must be constant or an address 4956 * of a static object with an optional offset. In the first case, 4957 * the result is returned in *offsp. In the second case, the static 4958 * object is returned in *symp and the offset in *offsp. 4959 * 4960 * The expression can consist of PLUS, MINUS, ADDR, NAME, STRING and 4961 * CON. Type conversions are allowed if they do not change binary 4962 * representation (including width). 4963 * 4964 * C99 6.6 "Constant expressions" 4965 * C99 6.7.8p4 restricts initializers for static storage duration 4966 */ 4967 bool 4968 constant_addr(const tnode_t *tn, const sym_t **symp, ptrdiff_t *offsp) 4969 { 4970 const sym_t *sym; 4971 ptrdiff_t offs1, offs2; 4972 tspec_t t, ot; 4973 4974 switch (tn->tn_op) { 4975 case MINUS: 4976 if (tn->u.ops.right->tn_op == CVT) 4977 return constant_addr(tn->u.ops.right, symp, offsp); 4978 else if (tn->u.ops.right->tn_op != CON) 4979 return false; 4980 /* FALLTHROUGH */ 4981 case PLUS: 4982 offs1 = offs2 = 0; 4983 if (tn->u.ops.left->tn_op == CON) { 4984 offs1 = (ptrdiff_t)tn->u.ops.left->u.value.u.integer; 4985 if (!constant_addr(tn->u.ops.right, &sym, &offs2)) 4986 return false; 4987 } else if (tn->u.ops.right->tn_op == CON) { 4988 offs2 = (ptrdiff_t)tn->u.ops.right->u.value.u.integer; 4989 if (tn->tn_op == MINUS) 4990 offs2 = -offs2; 4991 if (!constant_addr(tn->u.ops.left, &sym, &offs1)) 4992 return false; 4993 } else { 4994 return false; 4995 } 4996 *symp = sym; 4997 *offsp = offs1 + offs2; 4998 return true; 4999 case ADDR: 5000 if (tn->u.ops.left->tn_op == NAME) { 5001 *symp = tn->u.ops.left->u.sym; 5002 *offsp = 0; 5003 return true; 5004 } else { 5005 /* 5006 * If this were the front end of a compiler, we would 5007 * return a label instead of 0, at least if 5008 * 'tn->u.ops.left->tn_op == STRING'. 5009 */ 5010 *symp = NULL; 5011 *offsp = 0; 5012 return true; 5013 } 5014 case CVT: 5015 t = tn->tn_type->t_tspec; 5016 ot = tn->u.ops.left->tn_type->t_tspec; 5017 if ((!is_integer(t) && t != PTR) || 5018 (!is_integer(ot) && ot != PTR)) { 5019 return false; 5020 } 5021 #if 0 5022 /*- 5023 * consider: 5024 * struct foo { 5025 * unsigned char a; 5026 * } f = { 5027 * (unsigned char)(unsigned long) 5028 * (&(((struct foo *)0)->a)) 5029 * }; 5030 * since psize(unsigned long) != psize(unsigned char), 5031 * this fails. 5032 */ 5033 else if (psize(t) != psize(ot)) 5034 return -1; 5035 #endif 5036 return constant_addr(tn->u.ops.left, symp, offsp); 5037 default: 5038 return false; 5039 } 5040 } 5041 5042 /* Append s2 to s1, then free s2. */ 5043 buffer * 5044 cat_strings(buffer *s1, buffer *s2) 5045 { 5046 5047 if ((s1->data != NULL) != (s2->data != NULL)) { 5048 /* cannot concatenate wide and regular string literals */ 5049 error(292); 5050 return s1; 5051 } 5052 5053 if (s1->data != NULL) { 5054 while (s1->len + s2->len + 1 > s1->cap) 5055 s1->cap *= 2; 5056 s1->data = xrealloc(s1->data, s1->cap); 5057 memcpy(s1->data + s1->len, s2->data, s2->len + 1); 5058 free(s2->data); 5059 } 5060 s1->len += s2->len; 5061 free(s2); 5062 5063 return s1; 5064 } 5065 5066 5067 typedef struct stmt_expr { 5068 memory_pool se_mem; 5069 sym_t *se_sym; 5070 struct stmt_expr *se_enclosing; 5071 } stmt_expr; 5072 5073 static stmt_expr *stmt_exprs; 5074 5075 void 5076 begin_statement_expr(void) 5077 { 5078 debug_enter(); 5079 5080 stmt_expr *se = xmalloc(sizeof(*se)); 5081 se->se_mem = expr_save_memory(); 5082 se->se_sym = NULL; 5083 se->se_enclosing = stmt_exprs; 5084 stmt_exprs = se; 5085 } 5086 5087 void 5088 do_statement_expr(tnode_t *tn) 5089 { 5090 block_level--; 5091 mem_block_level--; 5092 stmt_exprs->se_sym = tn != NULL 5093 ? mktempsym(block_dup_type(tn->tn_type)) 5094 : NULL; /* after a syntax error */ 5095 mem_block_level++; 5096 block_level++; 5097 /* '({ ... })' is a GCC extension */ 5098 gnuism(320); 5099 } 5100 5101 tnode_t * 5102 end_statement_expr(void) 5103 { 5104 tnode_t *tn; 5105 5106 stmt_expr *se = stmt_exprs; 5107 if (se->se_sym == NULL) { 5108 tn = NULL; /* after a syntax error */ 5109 goto end; 5110 } 5111 5112 tn = build_name(se->se_sym, false); 5113 (void)expr_save_memory(); /* leak */ 5114 expr_restore_memory(se->se_mem); 5115 stmt_exprs = se->se_enclosing; 5116 free(se); 5117 5118 end: 5119 debug_leave(); 5120 return tn; 5121 } 5122 5123 bool 5124 in_statement_expr(void) 5125 { 5126 return stmt_exprs != NULL; 5127 } 5128
Indexes created Tue Sep 23 14:10:03 GMT 2025