tree.c revision 1.683
1 /* $NetBSD: tree.c,v 1.683 2025/05/04 08:37:09 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 1.683 2025/05/04 08:37:09 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 int64_t max = si_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 - max; 161 else 162 return max; 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 static const char * 597 function_call_descr(const function_call *call) 598 { 599 if ((call->func->tn_op == ADDR || call->func->tn_op == LOAD) 600 && call->func->u.ops.left->tn_op == NAME) 601 return call->func->u.ops.left->u.sym->s_name; 602 return type_name(call->func->tn_type->t_subt); 603 } 604 605 /* Create an expression from a unary or binary operator and its operands. */ 606 static tnode_t * 607 build_op(op_t op, bool sys, type_t *type, tnode_t *ln, tnode_t *rn) 608 { 609 610 tnode_t *ntn = expr_alloc_tnode(); 611 ntn->tn_op = op; 612 ntn->tn_type = type; 613 ntn->tn_sys = sys; 614 ntn->u.ops.left = ln; 615 ntn->u.ops.right = rn; 616 617 if (op == INDIR || op == FSEL) { 618 lint_assert(ln->tn_type->t_tspec == PTR); 619 tspec_t t = ln->tn_type->t_subt->t_tspec; 620 ntn->tn_lvalue = t != FUNC && t != VOID; 621 } 622 623 return ntn; 624 } 625 626 tnode_t * 627 build_constant(type_t *tp, val_t *v) 628 { 629 630 tnode_t *n = expr_alloc_tnode(); 631 n->tn_op = CON; 632 n->tn_type = tp; 633 n->u.value = *v; 634 n->u.value.v_tspec = tp->t_tspec; 635 free(v); 636 return n; 637 } 638 639 static tnode_t * 640 build_integer_constant(tspec_t t, int64_t si) 641 { 642 643 tnode_t *n = expr_alloc_tnode(); 644 n->tn_op = CON; 645 n->tn_type = gettyp(t); 646 n->u.value.v_tspec = t; 647 n->u.value.v_unsigned_since_c90 = false; 648 n->u.value.v_char_constant = false; 649 n->u.value.u.integer = si; 650 return n; 651 } 652 653 static void 654 fallback_symbol(sym_t *sym) 655 { 656 657 if (Tflag && fallback_symbol_strict_bool(sym)) 658 return; 659 660 if (funcsym != NULL && (strcmp(sym->s_name, "__FUNCTION__") == 0 || 661 strcmp(sym->s_name, "__PRETTY_FUNCTION__") == 0)) { 662 /* __FUNCTION__/__PRETTY_FUNCTION__ is a GCC extension */ 663 gnuism(316); 664 goto return_function_name; 665 } 666 667 if (funcsym != NULL && strcmp(sym->s_name, "__func__") == 0) { 668 if (!allow_c99) 669 /* __func__ is a C99 feature */ 670 warning(317); 671 /* C11 6.4.2.2 */ 672 return_function_name: 673 sym->s_type = block_derive_type(gettyp(CHAR), ARRAY); 674 sym->s_type->t_const = true; 675 sym->s_type->u.dimension = (int)strlen(funcsym->s_name) + 1; 676 return; 677 } 678 679 /* '%s' undefined */ 680 error(99, sym->s_name); 681 } 682 683 /* 684 * Functions that are predeclared by GCC or other compilers can be called 685 * with arbitrary arguments. Since lint usually runs after a successful 686 * compilation, it's the compiler's job to catch any errors. 687 */ 688 bool 689 is_compiler_builtin(const char *name) 690 { 691 /* https://gcc.gnu.org/onlinedocs/gcc/C-Extensions.html */ 692 if (allow_gcc) { 693 if (strncmp(name, "__atomic_", 9) == 0 || 694 strncmp(name, "__builtin_", 10) == 0 || 695 strcmp(name, "alloca") == 0 || 696 /* obsolete but still in use, as of 2021 */ 697 strncmp(name, "__sync_", 7) == 0) 698 return true; 699 } 700 701 /* https://software.intel.com/sites/landingpage/IntrinsicsGuide/ */ 702 if (strncmp(name, "_mm_", 4) == 0) 703 return true; 704 705 return false; 706 } 707 708 static bool 709 str_ends_with(const char *haystack, const char *needle) 710 { 711 size_t hlen = strlen(haystack); 712 size_t nlen = strlen(needle); 713 714 return nlen <= hlen && 715 memcmp(haystack + hlen - nlen, needle, nlen) == 0; 716 } 717 718 /* https://gcc.gnu.org/onlinedocs/gcc/Integer-Overflow-Builtins.html */ 719 static bool 720 is_gcc_bool_builtin(const char *name) 721 { 722 return strncmp(name, "__builtin_", 10) == 0 && 723 (str_ends_with(name, "_overflow") || 724 str_ends_with(name, "_overflow_p")); 725 } 726 727 static void 728 build_name_call(sym_t *sym) 729 { 730 731 if (is_compiler_builtin(sym->s_name)) { 732 /* 733 * Do not warn about these, just assume that they are regular 734 * functions compatible with non-prototype calling conventions. 735 */ 736 if (allow_gcc && is_gcc_bool_builtin(sym->s_name)) 737 sym->s_type = gettyp(BOOL); 738 } else if (allow_c99) 739 /* function '%s' implicitly declared to return int */ 740 error(215, sym->s_name); 741 else if (!allow_trad) 742 /* function '%s' implicitly declared to return int */ 743 warning(215, sym->s_name); 744 745 /* XXX if !allow_c90, the symbol should be exported to level 0 */ 746 sym->s_type = block_derive_type(sym->s_type, FUNC); 747 } 748 749 /* Create a node for a name (symbol table entry). */ 750 tnode_t * 751 build_name(sym_t *sym, bool is_funcname) 752 { 753 754 if (sym->s_scl == NO_SCL && !in_gcc_attribute) { 755 sym->s_scl = EXTERN; 756 sym->s_def = DECL; 757 if (is_funcname) 758 build_name_call(sym); 759 else 760 fallback_symbol(sym); 761 } 762 763 lint_assert(sym->s_kind == SK_VCFT || sym->s_kind == SK_MEMBER); 764 765 tnode_t *n = expr_alloc_tnode(); 766 n->tn_type = sym->s_type; 767 if (sym->s_scl == BOOL_CONST) { 768 n->tn_op = CON; 769 n->u.value.v_tspec = BOOL; 770 n->u.value.v_unsigned_since_c90 = false; 771 n->u.value.v_char_constant = false; 772 n->u.value.u.integer = sym->u.s_bool_constant ? 1 : 0; 773 } else if (sym->s_scl == ENUM_CONST) { 774 n->tn_op = CON; 775 n->u.value.v_tspec = INT; /* ENUM is in n->tn_type */ 776 n->u.value.v_unsigned_since_c90 = false; 777 n->u.value.v_char_constant = false; 778 n->u.value.u.integer = sym->u.s_enum_constant; 779 } else { 780 n->tn_op = NAME; 781 n->u.sym = sym; 782 if (sym->s_kind == SK_VCFT && sym->s_type->t_tspec != FUNC) 783 n->tn_lvalue = true; 784 } 785 786 return n; 787 } 788 789 tnode_t * 790 build_string(buffer *lit) 791 { 792 size_t value_len = lit->len; 793 if (lit->data != NULL) { 794 quoted_iterator it = { .end = 0 }; 795 for (value_len = 0; quoted_next(lit, &it); value_len++) 796 continue; 797 } 798 799 type_t *tp = expr_zero_alloc(sizeof(*tp), "type"); 800 tp->t_tspec = ARRAY; 801 tp->t_subt = gettyp(lit->data != NULL ? CHAR : WCHAR_TSPEC); 802 tp->u.dimension = (int)(value_len + 1); 803 804 tnode_t *n = expr_alloc_tnode(); 805 n->tn_op = STRING; 806 n->tn_type = tp; 807 n->tn_lvalue = true; 808 809 n->u.str_literals = expr_zero_alloc(sizeof(*n->u.str_literals), "tnode.string"); 810 n->u.str_literals->len = lit->len; 811 812 if (lit->data != NULL) { 813 n->u.str_literals->data = expr_zero_alloc(lit->len + 1, 814 "tnode.string.data"); 815 (void)memcpy(n->u.str_literals->data, lit->data, lit->len + 1); 816 free(lit->data); 817 } 818 free(lit); 819 820 return n; 821 } 822 823 tnode_t * 824 build_generic_selection(const tnode_t *expr, 825 struct generic_association *sel) 826 { 827 tnode_t *default_result = NULL; 828 829 for (; sel != NULL; sel = sel->ga_prev) { 830 if (expr != NULL && 831 types_compatible(sel->ga_arg, expr->tn_type, 832 false, false, NULL)) 833 return sel->ga_result; 834 else if (sel->ga_arg == NULL) 835 default_result = sel->ga_result; 836 } 837 return default_result; 838 } 839 840 static bool 841 is_out_of_char_range(const tnode_t *tn) 842 { 843 return tn->tn_op == CON && 844 !tn->u.value.v_char_constant && 845 !(0 <= tn->u.value.u.integer && 846 tn->u.value.u.integer < 1 << (CHAR_SIZE - 1)); 847 } 848 849 static bool 850 check_nonportable_char_comparison(op_t op, 851 const tnode_t *ln, tspec_t lt, 852 const tnode_t *rn, tspec_t rt) 853 { 854 if (!(hflag || pflag)) 855 return true; 856 857 if (lt == CHAR && is_out_of_char_range(rn)) { 858 char buf[128]; 859 (void)snprintf(buf, sizeof(buf), "%s %d", 860 op_name(op), (int)rn->u.value.u.integer); 861 /* nonportable character comparison '%s' */ 862 warning(230, buf); 863 return false; 864 } 865 if (rt == CHAR && is_out_of_char_range(ln)) { 866 char buf[128]; 867 (void)snprintf(buf, sizeof(buf), "%d %s ?", 868 (int)ln->u.value.u.integer, op_name(op)); 869 /* nonportable character comparison '%s' */ 870 warning(230, buf); 871 return false; 872 } 873 return true; 874 } 875 876 static void 877 check_integer_comparison(op_t op, tnode_t *ln, tnode_t *rn) 878 { 879 880 tspec_t lt = ln->tn_type->t_tspec; 881 tspec_t rt = rn->tn_type->t_tspec; 882 883 if (ln->tn_op != CON && rn->tn_op != CON) 884 return; 885 886 if (!is_integer(lt) || !is_integer(rt)) 887 return; 888 889 if (any_query_enabled && !in_system_header) { 890 if (lt == CHAR && rn->tn_op == CON && 891 !rn->u.value.v_char_constant) { 892 /* comparison '%s' of 'char' with plain integer %d */ 893 query_message(14, 894 op_name(op), (int)rn->u.value.u.integer); 895 } 896 if (rt == CHAR && ln->tn_op == CON && 897 !ln->u.value.v_char_constant) { 898 /* comparison '%s' of 'char' with plain integer %d */ 899 query_message(14, 900 op_name(op), (int)ln->u.value.u.integer); 901 } 902 } 903 904 if (!check_nonportable_char_comparison(op, ln, lt, rn, rt)) 905 return; 906 907 if (is_uinteger(lt) && !is_uinteger(rt) && 908 rn->tn_op == CON && rn->u.value.u.integer <= 0) { 909 if (rn->u.value.u.integer < 0) { 910 /* operator '%s' compares '%s' with '%s' */ 911 warning(162, op_name(op), 912 type_name(ln->tn_type), "negative constant"); 913 } else if (op == LT || op == GE) 914 /* operator '%s' compares '%s' with '%s' */ 915 warning(162, op_name(op), type_name(ln->tn_type), "0"); 916 return; 917 } 918 if (is_uinteger(rt) && !is_uinteger(lt) && 919 ln->tn_op == CON && ln->u.value.u.integer <= 0) { 920 if (ln->u.value.u.integer < 0) { 921 /* operator '%s' compares '%s' with '%s' */ 922 warning(162, op_name(op), 923 "negative constant", type_name(rn->tn_type)); 924 } else if (op == GT || op == LE) 925 /* operator '%s' compares '%s' with '%s' */ 926 warning(162, op_name(op), "0", type_name(rn->tn_type)); 927 return; 928 } 929 } 930 931 static const tspec_t arith_rank[] = { 932 LDOUBLE, DOUBLE, FLOAT, 933 #ifdef INT128_SIZE 934 UINT128, INT128, 935 #endif 936 ULLONG, LLONG, 937 ULONG, LONG, 938 UINT, INT, 939 }; 940 941 /* Keep unsigned in traditional C */ 942 static tspec_t 943 usual_arithmetic_conversion_trad(tspec_t lt, tspec_t rt) 944 { 945 946 size_t i; 947 for (i = 0; arith_rank[i] != INT; i++) 948 if (lt == arith_rank[i] || rt == arith_rank[i]) 949 break; 950 951 tspec_t t = arith_rank[i]; 952 if (is_uinteger(lt) || is_uinteger(rt)) 953 if (is_integer(t) && !is_uinteger(t)) 954 return unsigned_type(t); 955 return t; 956 } 957 958 static tspec_t 959 usual_arithmetic_conversion_c90(tspec_t lt, tspec_t rt) 960 { 961 962 if (lt == rt) 963 return lt; 964 965 if (lt == LCOMPLEX || rt == LCOMPLEX) 966 return LCOMPLEX; 967 if (lt == DCOMPLEX || rt == DCOMPLEX) 968 return DCOMPLEX; 969 if (lt == FCOMPLEX || rt == FCOMPLEX) 970 return FCOMPLEX; 971 if (lt == LDOUBLE || rt == LDOUBLE) 972 return LDOUBLE; 973 if (lt == DOUBLE || rt == DOUBLE) 974 return DOUBLE; 975 if (lt == FLOAT || rt == FLOAT) 976 return FLOAT; 977 978 if (size_in_bits(lt) > size_in_bits(rt)) 979 return lt; 980 if (size_in_bits(lt) < size_in_bits(rt)) 981 return rt; 982 983 size_t i; 984 for (i = 3; arith_rank[i] != INT; i++) 985 if (arith_rank[i] == lt || arith_rank[i] == rt) 986 break; 987 if ((is_uinteger(lt) || is_uinteger(rt)) && 988 !is_uinteger(arith_rank[i])) 989 i--; 990 return arith_rank[i]; 991 } 992 993 static tnode_t * 994 apply_usual_arithmetic_conversions(op_t op, tnode_t *tn, tspec_t t) 995 { 996 type_t *ntp = expr_dup_type(tn->tn_type); 997 ntp->t_tspec = t; 998 if (tn->tn_op != CON) { 999 /* usual arithmetic conversion for '%s' from '%s' to '%s' */ 1000 query_message(4, op_name(op), 1001 type_name(tn->tn_type), type_name(ntp)); 1002 } 1003 return convert(op, 0, ntp, tn); 1004 } 1005 1006 /* 1007 * Apply the "usual arithmetic conversions" (C99 6.3.1.8), which gives both 1008 * operands the same type. 1009 */ 1010 static void 1011 balance(op_t op, tnode_t **lnp, tnode_t **rnp) 1012 { 1013 1014 tspec_t lt = (*lnp)->tn_type->t_tspec; 1015 tspec_t rt = (*rnp)->tn_type->t_tspec; 1016 if (!is_arithmetic(lt) || !is_arithmetic(rt)) 1017 return; 1018 1019 tspec_t t = allow_c90 1020 ? usual_arithmetic_conversion_c90(lt, rt) 1021 : usual_arithmetic_conversion_trad(lt, rt); 1022 1023 if (modtab[op].m_comparison 1024 && is_integer(lt) && (*lnp)->tn_op != CON 1025 && is_floating(t) && (*rnp)->tn_op == CON) 1026 /* comparing integer '%s' to floating point constant %Lg */ 1027 warning(379, type_name((*lnp)->tn_type), 1028 (*rnp)->u.value.u.floating); 1029 1030 if (t != lt) 1031 *lnp = apply_usual_arithmetic_conversions(op, *lnp, t); 1032 if (t != rt) 1033 *rnp = apply_usual_arithmetic_conversions(op, *rnp, t); 1034 1035 if (is_integer(t)) { 1036 unsigned lw = width_in_bits((*lnp)->tn_type); 1037 unsigned rw = width_in_bits((*rnp)->tn_type); 1038 if (lw < rw) 1039 *lnp = convert(NOOP, 0, (*rnp)->tn_type, *lnp); 1040 if (rw < lw) 1041 *rnp = convert(NOOP, 0, (*lnp)->tn_type, *rnp); 1042 } 1043 } 1044 1045 static tnode_t * 1046 build_address(bool sys, tnode_t *tn) 1047 { 1048 /* eliminate '&*' */ 1049 if (tn->tn_op == INDIR && 1050 tn->u.ops.left->tn_type->t_tspec == PTR && 1051 tn->u.ops.left->tn_type->t_subt == tn->tn_type) { 1052 return tn->u.ops.left; 1053 } 1054 1055 return build_op(ADDR, sys, expr_derive_type(tn->tn_type, PTR), 1056 tn, NULL); 1057 } 1058 1059 static uint64_t 1060 fold_unsigned_integer(op_t op, uint64_t l, uint64_t r, 1061 uint64_t max_value, bool *overflow) 1062 { 1063 switch (op) { 1064 case COMPL: 1065 return ~l & max_value; 1066 case UPLUS: 1067 return +l; 1068 case UMINUS: 1069 return -l & max_value; 1070 case MULT: 1071 *overflow = r > 0 && l > max_value / r; 1072 return l * r; 1073 case DIV: 1074 if (r == 0) { 1075 /* division by 0 */ 1076 error(139); 1077 return max_value; 1078 } 1079 return l / r; 1080 case MOD: 1081 if (r == 0) { 1082 /* modulus by 0 */ 1083 error(140); 1084 return 0; 1085 } 1086 return l % r; 1087 case PLUS: 1088 *overflow = l > max_value - r; 1089 return l + r; 1090 case MINUS: 1091 *overflow = l < r; 1092 return l - r; 1093 case SHL: 1094 /* TODO: warn about out-of-bounds 'r'. */ 1095 /* TODO: warn about overflow. */ 1096 return l << (r & 63); 1097 case SHR: 1098 /* TODO: warn about out-of-bounds 'r'. */ 1099 return l >> (r & 63); 1100 case LT: 1101 return l < r ? 1 : 0; 1102 case LE: 1103 return l <= r ? 1 : 0; 1104 case GT: 1105 return l > r ? 1 : 0; 1106 case GE: 1107 return l >= r ? 1 : 0; 1108 case EQ: 1109 return l == r ? 1 : 0; 1110 case NE: 1111 return l != r ? 1 : 0; 1112 case BITAND: 1113 return l & r; 1114 case BITXOR: 1115 return l ^ r; 1116 case BITOR: 1117 return l | r; 1118 default: 1119 lint_assert(false); 1120 /* NOTREACHED */ 1121 } 1122 } 1123 1124 static int64_t 1125 fold_signed_integer(op_t op, int64_t l, int64_t r, 1126 int64_t min_value, int64_t max_value, bool *overflow) 1127 { 1128 switch (op) { 1129 case COMPL: 1130 return ~l; 1131 case UPLUS: 1132 return +l; 1133 case UMINUS: 1134 *overflow = l == min_value; 1135 return *overflow ? l : -l; 1136 case MULT:; 1137 uint64_t al = s64_abs(l); 1138 uint64_t ar = s64_abs(r); 1139 bool neg = (l >= 0) != (r >= 0); 1140 uint64_t max_prod = (uint64_t)max_value + (neg ? 1 : 0); 1141 if (al > 0 && ar > max_prod / al) { 1142 *overflow = true; 1143 return neg ? min_value : max_value; 1144 } 1145 return l * r; 1146 case DIV: 1147 if (r == 0) { 1148 /* division by 0 */ 1149 error(139); 1150 return max_value; 1151 } 1152 if (l == min_value && r == -1) { 1153 *overflow = true; 1154 return l; 1155 } 1156 return l / r; 1157 case MOD: 1158 if (r == 0) { 1159 /* modulus by 0 */ 1160 error(140); 1161 return 0; 1162 } 1163 if (l == min_value && r == -1) { 1164 *overflow = true; 1165 return 0; 1166 } 1167 return l % r; 1168 case PLUS: 1169 if (r > 0 && l > max_value - r) { 1170 *overflow = true; 1171 return max_value; 1172 } 1173 if (r < 0 && l < min_value - r) { 1174 *overflow = true; 1175 return min_value; 1176 } 1177 return l + r; 1178 case MINUS: 1179 if (r > 0 && l < min_value + r) { 1180 *overflow = true; 1181 return min_value; 1182 } 1183 if (r < 0 && l > max_value + r) { 1184 *overflow = true; 1185 return max_value; 1186 } 1187 return l - r; 1188 case SHL: 1189 /* TODO: warn about out-of-bounds 'r'. */ 1190 /* TODO: warn about overflow. */ 1191 return l << (r & 63); 1192 case SHR: 1193 /* TODO: warn about out-of-bounds 'r'. */ 1194 return s64_shr(l, r & 63); 1195 case LT: 1196 return l < r ? 1 : 0; 1197 case LE: 1198 return l <= r ? 1 : 0; 1199 case GT: 1200 return l > r ? 1 : 0; 1201 case GE: 1202 return l >= r ? 1 : 0; 1203 case EQ: 1204 return l == r ? 1 : 0; 1205 case NE: 1206 return l != r ? 1 : 0; 1207 case BITAND: 1208 return l & r; 1209 case BITXOR: 1210 return l ^ r; 1211 case BITOR: 1212 return l | r; 1213 default: 1214 lint_assert(false); 1215 /* NOTREACHED */ 1216 } 1217 } 1218 1219 static tnode_t * 1220 fold_constant_integer(tnode_t *tn) 1221 { 1222 1223 lint_assert(has_operands(tn)); 1224 tspec_t t = tn->u.ops.left->tn_type->t_tspec; 1225 int64_t l = tn->u.ops.left->u.value.u.integer; 1226 int64_t r = is_binary(tn) ? tn->u.ops.right->u.value.u.integer : 0; 1227 uint64_t mask = value_bits(size_in_bits(t)); 1228 1229 int64_t res; 1230 bool overflow = false; 1231 if (!is_integer(t) || is_uinteger(t)) { 1232 uint64_t u_res = fold_unsigned_integer(tn->tn_op, 1233 (uint64_t)l, (uint64_t)r, mask, &overflow); 1234 if (u_res > mask) 1235 overflow = true; 1236 res = (int64_t)u_res; 1237 if (overflow && hflag) { 1238 char buf[128]; 1239 if (is_binary(tn)) { 1240 snprintf(buf, sizeof(buf), "%ju %s %ju", 1241 (uintmax_t)l, op_name(tn->tn_op), 1242 (uintmax_t)r); 1243 } else { 1244 snprintf(buf, sizeof(buf), "%s%ju", 1245 op_name(tn->tn_op), (uintmax_t)l); 1246 } 1247 /* '%s' overflows '%s' */ 1248 warning(141, buf, type_name(tn->tn_type)); 1249 } 1250 } else { 1251 int64_t max_value = (int64_t)(mask >> 1); 1252 int64_t min_value = -max_value - 1; 1253 res = fold_signed_integer(tn->tn_op, 1254 l, r, min_value, max_value, &overflow); 1255 if (res < min_value || res > max_value) 1256 overflow = true; 1257 if (overflow && hflag) { 1258 char buf[128]; 1259 if (is_binary(tn)) { 1260 snprintf(buf, sizeof(buf), "%jd %s %jd", 1261 (intmax_t)l, op_name(tn->tn_op), 1262 (intmax_t)r); 1263 } else if (tn->tn_op == UMINUS && l < 0) { 1264 snprintf(buf, sizeof(buf), "-(%jd)", 1265 (intmax_t)l); 1266 } else { 1267 snprintf(buf, sizeof(buf), "%s%jd", 1268 op_name(tn->tn_op), (intmax_t)l); 1269 } 1270 /* '%s' overflows '%s' */ 1271 warning(141, buf, type_name(tn->tn_type)); 1272 } 1273 } 1274 1275 val_t *v = xcalloc(1, sizeof(*v)); 1276 v->v_tspec = tn->tn_type->t_tspec; 1277 v->u.integer = convert_integer(res, t, size_in_bits(t)); 1278 1279 tnode_t *cn = build_constant(tn->tn_type, v); 1280 if (tn->u.ops.left->tn_system_dependent) 1281 cn->tn_system_dependent = true; 1282 if (is_binary(tn) && tn->u.ops.right->tn_system_dependent) 1283 cn->tn_system_dependent = true; 1284 1285 return cn; 1286 } 1287 1288 static tnode_t * 1289 build_struct_access(op_t op, bool sys, tnode_t *ln, tnode_t *rn) 1290 { 1291 1292 lint_assert(rn->tn_op == NAME); 1293 lint_assert(is_member(rn->u.sym)); 1294 1295 bool lvalue = op == ARROW || ln->tn_lvalue; 1296 1297 if (op == POINT) 1298 ln = build_address(sys, ln); 1299 else if (ln->tn_type->t_tspec != PTR) { 1300 lint_assert(!allow_c90); 1301 lint_assert(is_integer(ln->tn_type->t_tspec)); 1302 ln = convert(NOOP, 0, expr_derive_type(gettyp(VOID), PTR), ln); 1303 } 1304 1305 tnode_t *ctn = build_integer_constant(PTRDIFF_TSPEC, 1306 rn->u.sym->u.s_member.sm_offset_in_bits / CHAR_SIZE); 1307 1308 type_t *ptr_tp = expr_derive_type(rn->tn_type, PTR); 1309 tnode_t *ntn = build_op(PLUS, sys, ptr_tp, ln, ctn); 1310 if (ln->tn_op == CON) 1311 ntn = fold_constant_integer(ntn); 1312 1313 op_t nop = rn->tn_type->t_bitfield ? FSEL : INDIR; 1314 ntn = build_op(nop, sys, ntn->tn_type->t_subt, ntn, NULL); 1315 if (!lvalue) 1316 ntn->tn_lvalue = false; 1317 1318 return ntn; 1319 } 1320 1321 /* 1322 * Get the size in bytes of type tp->t_subt, as a constant expression of type 1323 * ptrdiff_t as seen from the target platform. 1324 */ 1325 static tnode_t * 1326 subt_size_in_bytes(type_t *tp) 1327 { 1328 1329 lint_assert(tp->t_tspec == PTR); 1330 tp = tp->t_subt; 1331 1332 int elem = 1; 1333 while (tp->t_tspec == ARRAY) { 1334 elem *= tp->u.dimension; 1335 tp = tp->t_subt; 1336 } 1337 1338 int elsz_in_bits = 0; 1339 switch (tp->t_tspec) { 1340 case FUNC: 1341 /* pointer to function is not allowed here */ 1342 error(110); 1343 break; 1344 case VOID: 1345 /* cannot do pointer arithmetic on operand of unknown size */ 1346 gnuism(136); 1347 break; 1348 case STRUCT: 1349 case UNION: 1350 if ((elsz_in_bits = (int)tp->u.sou->sou_size_in_bits) == 0) 1351 /* cannot do pointer arithmetic on operand of ... */ 1352 error(136); 1353 break; 1354 case ENUM: 1355 if (is_incomplete(tp)) 1356 /* cannot do pointer arithmetic on operand of ... */ 1357 warning(136); 1358 /* FALLTHROUGH */ 1359 default: 1360 if ((elsz_in_bits = size_in_bits(tp->t_tspec)) == 0) 1361 /* cannot do pointer arithmetic on operand of ... */ 1362 error(136); 1363 else 1364 lint_assert(elsz_in_bits != -1); 1365 break; 1366 } 1367 1368 if (elem == 0 && elsz_in_bits != 0) 1369 /* cannot do pointer arithmetic on operand of unknown size */ 1370 error(136); 1371 1372 if (elsz_in_bits == 0) 1373 elsz_in_bits = CHAR_SIZE; 1374 1375 return build_integer_constant(PTRDIFF_TSPEC, 1376 (int64_t)(elem * elsz_in_bits / CHAR_SIZE)); 1377 } 1378 1379 static tnode_t * 1380 build_prepost_incdec(op_t op, bool sys, tnode_t *ln) 1381 { 1382 1383 lint_assert(ln != NULL); 1384 tnode_t *cn = ln->tn_type->t_tspec == PTR 1385 ? subt_size_in_bytes(ln->tn_type) 1386 : build_integer_constant(INT, 1); 1387 return build_op(op, sys, ln->tn_type, ln, cn); 1388 } 1389 1390 static void 1391 check_enum_array_index(const tnode_t *ln, const tnode_t *rn) 1392 { 1393 1394 if (ln->tn_op != ADDR || ln->u.ops.left->tn_op != NAME) 1395 return; 1396 1397 const type_t *ltp = ln->u.ops.left->tn_type; 1398 if (ltp->t_tspec != ARRAY || ltp->t_incomplete_array) 1399 return; 1400 1401 if (rn->tn_op != CVT || !rn->tn_type->t_is_enum) 1402 return; 1403 if (rn->u.ops.left->tn_op != LOAD) 1404 return; 1405 1406 const type_t *rtp = rn->u.ops.left->tn_type; 1407 const sym_t *ec = rtp->u.enumer->en_first_enumerator; 1408 const sym_t *max_ec = ec; 1409 lint_assert(ec != NULL); 1410 for (ec = ec->s_next; ec != NULL; ec = ec->s_next) 1411 if (ec->u.s_enum_constant > max_ec->u.s_enum_constant) 1412 max_ec = ec; 1413 1414 int64_t max_enum_value = max_ec->u.s_enum_constant; 1415 lint_assert(INT_MIN <= max_enum_value && max_enum_value <= INT_MAX); 1416 1417 int max_array_index = ltp->u.dimension - 1; 1418 if (max_enum_value == max_array_index) 1419 return; 1420 1421 if (max_enum_value == max_array_index + 1 && 1422 (strstr(max_ec->s_name, "MAX") != NULL || 1423 strstr(max_ec->s_name, "max") != NULL || 1424 strstr(max_ec->s_name, "NUM") != NULL || 1425 strstr(max_ec->s_name, "num") != NULL || 1426 strncmp(max_ec->s_name, "N_", 2) == 0)) 1427 return; 1428 1429 /* maximum value %d for '%s' of type '%s' does not match maximum array index %d */ 1430 warning(348, (int)max_enum_value, max_ec->s_name, type_name(rtp), 1431 max_array_index); 1432 print_previous_declaration(max_ec); 1433 } 1434 1435 static tnode_t * 1436 build_plus_minus(op_t op, bool sys, tnode_t *ln, tnode_t *rn) 1437 { 1438 1439 if (rn->tn_type->t_tspec == PTR && is_integer(ln->tn_type->t_tspec)) { 1440 tnode_t *tmp = ln; 1441 ln = rn; 1442 rn = tmp; 1443 /* pointer addition has integer on the left-hand side */ 1444 query_message(5); 1445 } 1446 1447 /* pointer +- integer */ 1448 tspec_t lt = ln->tn_type->t_tspec; 1449 tspec_t rt = rn->tn_type->t_tspec; 1450 if (lt == PTR && rt != PTR) { 1451 lint_assert(is_integer(rt)); 1452 1453 check_ctype_macro_invocation(ln, rn); 1454 check_enum_array_index(ln, rn); 1455 1456 tnode_t *elsz = subt_size_in_bytes(ln->tn_type); 1457 tspec_t szt = elsz->tn_type->t_tspec; 1458 if (rt != szt && rt != unsigned_type(szt)) 1459 rn = convert(NOOP, 0, elsz->tn_type, rn); 1460 1461 tnode_t *prod = build_op(MULT, sys, rn->tn_type, rn, elsz); 1462 if (rn->tn_op == CON) 1463 prod = fold_constant_integer(prod); 1464 1465 return build_op(op, sys, ln->tn_type, ln, prod); 1466 } 1467 1468 /* pointer - pointer */ 1469 if (rt == PTR) { 1470 lint_assert(lt == PTR); 1471 lint_assert(op == MINUS); 1472 1473 type_t *ptrdiff = gettyp(PTRDIFF_TSPEC); 1474 tnode_t *raw_diff = build_op(op, sys, ptrdiff, ln, rn); 1475 if (ln->tn_op == CON && rn->tn_op == CON) 1476 raw_diff = fold_constant_integer(raw_diff); 1477 1478 tnode_t *elsz = subt_size_in_bytes(ln->tn_type); 1479 balance(NOOP, &raw_diff, &elsz); 1480 1481 return build_op(DIV, sys, ptrdiff, raw_diff, elsz); 1482 } 1483 1484 return build_op(op, sys, ln->tn_type, ln, rn); 1485 } 1486 1487 static tnode_t * 1488 build_bit_shift(op_t op, bool sys, tnode_t *ln, tnode_t *rn) 1489 { 1490 1491 if (!allow_c90 && rn->tn_type->t_tspec != INT) 1492 // XXX: C1978 7.5 says: "Both [operators] perform the usual 1493 // arithmetic conversions on their operands." 1494 // TODO: Add a test to exercise this part of the code. 1495 rn = convert(NOOP, 0, gettyp(INT), rn); 1496 return build_op(op, sys, ln->tn_type, ln, rn); 1497 } 1498 1499 static bool 1500 is_null_pointer(const tnode_t *tn) 1501 { 1502 tspec_t t = tn->tn_type->t_tspec; 1503 1504 // TODO: Investigate how other pointers are stored, in particular, 1505 // whether a pointer constant can have a non-zero value. 1506 // If not, simplify the code below. 1507 return ((t == PTR && tn->tn_type->t_subt->t_tspec == VOID) 1508 || is_integer(t)) 1509 && (tn->tn_op == CON && tn->u.value.u.integer == 0); 1510 } 1511 1512 /* Return a type based on tp1, with added qualifiers from tp2. */ 1513 static type_t * 1514 merge_qualifiers(type_t *tp1, const type_t *tp2) 1515 { 1516 1517 lint_assert(tp1->t_tspec == PTR); 1518 lint_assert(tp2->t_tspec == PTR); 1519 1520 bool c1 = tp1->t_subt->t_const; 1521 bool c2 = tp2->t_subt->t_const; 1522 bool v1 = tp1->t_subt->t_volatile; 1523 bool v2 = tp2->t_subt->t_volatile; 1524 1525 if (c1 == (c1 | c2) && v1 == (v1 | v2)) 1526 return tp1; 1527 1528 type_t *nstp = expr_dup_type(tp1->t_subt); 1529 nstp->t_const |= c2; 1530 nstp->t_volatile |= v2; 1531 1532 type_t *ntp = expr_dup_type(tp1); 1533 ntp->t_subt = nstp; 1534 return ntp; 1535 } 1536 1537 /* See C99 6.5.15 "Conditional operator". */ 1538 static tnode_t * 1539 build_colon(bool sys, tnode_t *ln, tnode_t *rn) 1540 { 1541 tspec_t lt = ln->tn_type->t_tspec; 1542 tspec_t rt = rn->tn_type->t_tspec; 1543 1544 type_t *tp; 1545 if (is_arithmetic(lt) && is_arithmetic(rt)) 1546 /* The operands were already balanced in build_binary. */ 1547 tp = ln->tn_type; 1548 else if (lt == BOOL && rt == BOOL) 1549 tp = ln->tn_type; 1550 else if (lt == VOID || rt == VOID) 1551 tp = gettyp(VOID); 1552 else if (is_struct_or_union(lt)) { 1553 lint_assert(is_struct_or_union(rt)); 1554 lint_assert(ln->tn_type->u.sou == rn->tn_type->u.sou); 1555 if (is_incomplete(ln->tn_type)) { 1556 /* unknown operand size, op '%s' */ 1557 error(138, op_name(COLON)); 1558 return NULL; 1559 } 1560 tp = ln->tn_type; 1561 } else if (lt == PTR && is_integer(rt)) { 1562 if (rt != PTRDIFF_TSPEC) 1563 rn = convert(NOOP, 0, gettyp(PTRDIFF_TSPEC), rn); 1564 tp = ln->tn_type; 1565 } else if (rt == PTR && is_integer(lt)) { 1566 if (lt != PTRDIFF_TSPEC) 1567 ln = convert(NOOP, 0, gettyp(PTRDIFF_TSPEC), ln); 1568 tp = rn->tn_type; 1569 } else if (lt == PTR && is_null_pointer(rn)) 1570 tp = merge_qualifiers(ln->tn_type, rn->tn_type); 1571 else if (rt == PTR && is_null_pointer(ln)) 1572 tp = merge_qualifiers(rn->tn_type, ln->tn_type); 1573 else if (lt == PTR && ln->tn_type->t_subt->t_tspec == VOID) 1574 tp = merge_qualifiers(ln->tn_type, rn->tn_type); 1575 else if (rt == PTR && rn->tn_type->t_subt->t_tspec == VOID) 1576 tp = merge_qualifiers(rn->tn_type, ln->tn_type); 1577 else { 1578 /* 1579 * XXX For now we simply take the left type. This is probably 1580 * wrong, if one type contains a function prototype and the 1581 * other one, at the same place, only an old-style declaration. 1582 */ 1583 tp = merge_qualifiers(ln->tn_type, rn->tn_type); 1584 } 1585 1586 return build_op(COLON, sys, tp, ln, rn); 1587 } 1588 1589 /* TODO: check for varargs */ 1590 static bool 1591 is_cast_redundant(const tnode_t *tn) 1592 { 1593 const type_t *ntp = tn->tn_type, *otp = tn->u.ops.left->tn_type; 1594 tspec_t nt = ntp->t_tspec, ot = otp->t_tspec; 1595 1596 if (nt == BOOL || ot == BOOL) 1597 return nt == BOOL && ot == BOOL; 1598 1599 if (is_integer(nt) && is_integer(ot)) { 1600 unsigned int nw = width_in_bits(ntp), ow = width_in_bits(otp); 1601 if (is_uinteger(nt) == is_uinteger(ot)) 1602 return nw >= ow; 1603 return is_uinteger(ot) && nw > ow; 1604 } 1605 1606 if (is_complex(nt) || is_complex(ot)) 1607 return is_complex(nt) && is_complex(ot) && 1608 size_in_bits(nt) >= size_in_bits(ot); 1609 1610 if (is_floating(nt) && is_floating(ot)) 1611 return size_in_bits(nt) >= size_in_bits(ot); 1612 1613 if (nt == PTR && ot == PTR) { 1614 if (!ntp->t_subt->t_const && otp->t_subt->t_const) 1615 return false; 1616 if (!ntp->t_subt->t_volatile && otp->t_subt->t_volatile) 1617 return false; 1618 1619 if (ntp->t_subt->t_tspec == VOID || 1620 otp->t_subt->t_tspec == VOID || 1621 types_compatible(ntp->t_subt, otp->t_subt, 1622 false, false, NULL)) 1623 return true; 1624 } 1625 1626 return false; 1627 } 1628 1629 static bool 1630 is_assignment(op_t op) 1631 { 1632 1633 return op == ASSIGN || 1634 op == MULASS || 1635 op == DIVASS || 1636 op == MODASS || 1637 op == ADDASS || 1638 op == SUBASS || 1639 op == SHLASS || 1640 op == SHRASS || 1641 op == ANDASS || 1642 op == XORASS || 1643 op == ORASS || 1644 op == RETURN || 1645 op == INIT; 1646 } 1647 1648 static tnode_t * 1649 build_assignment(op_t op, bool sys, tnode_t *ln, tnode_t *rn) 1650 { 1651 1652 tspec_t lt = ln->tn_type->t_tspec; 1653 tspec_t rt = rn->tn_type->t_tspec; 1654 1655 if (is_assignment(rn->tn_op)) 1656 /* chained assignment with '%s' and '%s' */ 1657 query_message(10, op_name(op), op_name(rn->tn_op)); 1658 1659 if ((op == ADDASS || op == SUBASS) && lt == PTR) { 1660 lint_assert(is_integer(rt)); 1661 tnode_t *ctn = subt_size_in_bytes(ln->tn_type); 1662 if (rn->tn_type->t_tspec != ctn->tn_type->t_tspec) 1663 rn = convert(NOOP, 0, ctn->tn_type, rn); 1664 rn = build_op(MULT, sys, rn->tn_type, rn, ctn); 1665 if (rn->u.ops.left->tn_op == CON) 1666 rn = fold_constant_integer(rn); 1667 } 1668 1669 if ((op == ASSIGN || op == RETURN || op == INIT) && 1670 (lt == STRUCT || rt == STRUCT)) { 1671 lint_assert(lt == rt); 1672 lint_assert(ln->tn_type->u.sou == rn->tn_type->u.sou); 1673 if (is_incomplete(ln->tn_type)) { 1674 if (op == RETURN) 1675 /* cannot return incomplete type */ 1676 error(212); 1677 else 1678 /* unknown operand size, op '%s' */ 1679 error(138, op_name(op)); 1680 return NULL; 1681 } 1682 } 1683 1684 if (op == SHLASS && hflag && allow_trad && allow_c90 1685 && portable_rank_cmp(lt, rt) < 0) 1686 /* semantics of '%s' change in C90; ... */ 1687 warning(118, "<<="); 1688 1689 if (op != SHLASS && op != SHRASS 1690 && (op == ASSIGN || lt != PTR) 1691 && (lt != rt || (ln->tn_type->t_bitfield && rn->tn_op == CON))) { 1692 rn = convert(op, 0, ln->tn_type, rn); 1693 rt = lt; 1694 } 1695 1696 if (lt == PTR && ln->tn_type->t_subt->t_tspec != VOID 1697 && rt == PTR && rn->tn_type->t_subt->t_tspec == VOID 1698 && !is_null_pointer(rn)) 1699 /* implicit narrowing conversion from void ... */ 1700 query_message(20, type_name(ln->tn_type)); 1701 1702 if (any_query_enabled && rn->tn_op == CVT && rn->tn_cast && 1703 types_compatible(ln->tn_type, rn->tn_type, false, false, NULL) && 1704 is_cast_redundant(rn)) { 1705 /* redundant cast from '%s' to '%s' before assignment */ 1706 query_message(7, type_name(rn->u.ops.left->tn_type), 1707 type_name(rn->tn_type)); 1708 } 1709 1710 return build_op(op, sys, ln->tn_type, ln, rn); 1711 } 1712 1713 static tnode_t * 1714 build_real_imag(op_t op, bool sys, tnode_t *ln) 1715 { 1716 1717 lint_assert(ln != NULL); 1718 if (ln->tn_op == NAME) { 1719 /* 1720 * This may be too much, but it avoids wrong warnings. See 1721 * d_c99_complex_split.c. 1722 */ 1723 mark_as_used(ln->u.sym, false, false); 1724 mark_as_set(ln->u.sym); 1725 } 1726 1727 tspec_t t; 1728 switch (ln->tn_type->t_tspec) { 1729 case LCOMPLEX: 1730 t = LDOUBLE; 1731 break; 1732 case DCOMPLEX: 1733 t = DOUBLE; 1734 break; 1735 case FCOMPLEX: 1736 t = FLOAT; 1737 break; 1738 default: 1739 /* '__%s__' is invalid for type '%s' */ 1740 error(276, op == REAL ? "real" : "imag", 1741 type_name(ln->tn_type)); 1742 return NULL; 1743 } 1744 1745 tnode_t *ntn = build_op(op, sys, gettyp(t), ln, NULL); 1746 ntn->tn_lvalue = true; 1747 return ntn; 1748 } 1749 1750 static bool 1751 is_confusing_precedence(op_t op, const tnode_t *operand, op_t *cop) 1752 { 1753 if (operand->tn_parenthesized) 1754 return false; 1755 op_t oop = operand->tn_op; 1756 1757 if (op == SHL || op == SHR) { 1758 if (oop == PLUS || oop == MINUS) 1759 return *cop = oop, true; 1760 return false; 1761 } 1762 1763 if (op == LOGOR) { 1764 if (oop == LOGAND) 1765 return *cop = oop, true; 1766 return false; 1767 } 1768 1769 lint_assert(op == BITAND || op == BITXOR || op == BITOR); 1770 if (oop != op 1771 && (oop == PLUS || oop == MINUS || oop == BITAND || oop == BITXOR)) 1772 return *cop = oop, true; 1773 return false; 1774 } 1775 1776 /* 1777 * Print a warning if the given node has operands which should be 1778 * parenthesized. 1779 * 1780 * XXX Does not work if an operand is a constant expression. Constant 1781 * expressions are already folded. 1782 */ 1783 static void 1784 check_precedence_confusion(tnode_t *tn) 1785 { 1786 tnode_t *ln, *rn; 1787 1788 if (!hflag) 1789 return; 1790 1791 debug_node(tn); 1792 1793 lint_assert(is_binary(tn)); 1794 for (ln = tn->u.ops.left; ln->tn_op == CVT; ln = ln->u.ops.left) 1795 continue; 1796 for (rn = tn->u.ops.right; rn->tn_op == CVT; rn = rn->u.ops.left) 1797 continue; 1798 1799 op_t cop; 1800 if (is_confusing_precedence(tn->tn_op, ln, &cop) || 1801 is_confusing_precedence(tn->tn_op, rn, &cop)) { 1802 /* possible precedence confusion between '%s' and '%s' */ 1803 warning(169, op_name(tn->tn_op), op_name(cop)); 1804 } 1805 } 1806 1807 static tnode_t * 1808 fold_constant_compare_zero(tnode_t *tn) 1809 { 1810 1811 val_t *v = xcalloc(1, sizeof(*v)); 1812 v->v_tspec = tn->tn_type->t_tspec; 1813 lint_assert(v->v_tspec == INT || (Tflag && v->v_tspec == BOOL)); 1814 1815 lint_assert(has_operands(tn)); 1816 bool l = constant_is_nonzero(tn->u.ops.left); 1817 bool r = is_binary(tn) && constant_is_nonzero(tn->u.ops.right); 1818 1819 switch (tn->tn_op) { 1820 case NOT: 1821 v->u.integer = !l ? 1 : 0; 1822 break; 1823 case LOGAND: 1824 v->u.integer = l && r ? 1 : 0; 1825 break; 1826 case LOGOR: 1827 v->u.integer = l || r ? 1 : 0; 1828 break; 1829 default: 1830 lint_assert(false); 1831 } 1832 1833 return build_constant(tn->tn_type, v); 1834 } 1835 1836 static long double 1837 floating_error_value(tspec_t t, long double lv) 1838 { 1839 if (t == FLOAT) 1840 return lv < 0 ? -FLT_MAX : FLT_MAX; 1841 if (t == DOUBLE) 1842 return lv < 0 ? -DBL_MAX : DBL_MAX; 1843 /* 1844 * When NetBSD is cross-built in MKLINT=yes mode on x86_64 for sparc64, 1845 * tools/lint checks this code while building usr.bin/xlint. In that 1846 * situation, lint uses the preprocessor for sparc64, in which the type 1847 * 'long double' is IEEE-754-binary128, affecting the macro LDBL_MAX 1848 * below. The type 'long double', as well as the strtold 1849 * implementation, comes from the host platform x86_64 though, where 1850 * 'long double' consumes 128 bits as well but only uses 80 of them. 1851 * The exponent range of the two 'long double' types is the same, but 1852 * the maximum finite value differs due to the extended precision on 1853 * sparc64. 1854 * 1855 * To properly handle the data types of the target platform, lint would 1856 * have to implement the floating-point types in a platform-independent 1857 * way, which is not worth the effort, given how few programs 1858 * practically use 'long double'. 1859 */ 1860 /* LINTED 248: floating-point constant out of range */ 1861 long double max = LDBL_MAX; 1862 return lv < 0 ? -max : max; 1863 } 1864 1865 static bool 1866 is_floating_overflow(tspec_t t, long double val) 1867 { 1868 if (fpe != 0 || isfinite(val) == 0) 1869 return true; 1870 if (t == FLOAT && (val > FLT_MAX || val < -FLT_MAX)) 1871 return true; 1872 if (t == DOUBLE && (val > DBL_MAX || val < -DBL_MAX)) 1873 return true; 1874 return false; 1875 } 1876 1877 static tnode_t * 1878 fold_constant_floating(tnode_t *tn) 1879 { 1880 1881 fpe = 0; 1882 1883 tspec_t t = tn->tn_type->t_tspec; 1884 1885 val_t *v = xcalloc(1, sizeof(*v)); 1886 v->v_tspec = t; 1887 1888 lint_assert(is_floating(t)); 1889 lint_assert(has_operands(tn)); 1890 lint_assert(t == tn->u.ops.left->tn_type->t_tspec); 1891 lint_assert(!is_binary(tn) || t == tn->u.ops.right->tn_type->t_tspec); 1892 1893 long double lv = tn->u.ops.left->u.value.u.floating; 1894 long double rv = is_binary(tn) ? tn->u.ops.right->u.value.u.floating 1895 : 0.0; 1896 1897 switch (tn->tn_op) { 1898 case UPLUS: 1899 v->u.floating = lv; 1900 break; 1901 case UMINUS: 1902 v->u.floating = -lv; 1903 break; 1904 case MULT: 1905 v->u.floating = lv * rv; 1906 break; 1907 case DIV: 1908 if (rv == 0.0) { 1909 /* division by 0 */ 1910 error(139); 1911 v->u.floating = floating_error_value(t, lv); 1912 } else { 1913 v->u.floating = lv / rv; 1914 } 1915 break; 1916 case PLUS: 1917 v->u.floating = lv + rv; 1918 break; 1919 case MINUS: 1920 v->u.floating = lv - rv; 1921 break; 1922 case LT: 1923 v->u.integer = lv < rv ? 1 : 0; 1924 break; 1925 case LE: 1926 v->u.integer = lv <= rv ? 1 : 0; 1927 break; 1928 case GE: 1929 v->u.integer = lv >= rv ? 1 : 0; 1930 break; 1931 case GT: 1932 v->u.integer = lv > rv ? 1 : 0; 1933 break; 1934 case EQ: 1935 v->u.integer = lv == rv ? 1 : 0; 1936 break; 1937 case NE: 1938 v->u.integer = lv != rv ? 1 : 0; 1939 break; 1940 default: 1941 lint_assert(false); 1942 } 1943 1944 // XXX: Must not access u.floating after setting u.integer. 1945 lint_assert(fpe != 0 || isnan(v->u.floating) == 0); 1946 if (is_complex(v->v_tspec)) { 1947 /* 1948 * Don't warn, as lint doesn't model the imaginary part of 1949 * complex numbers. 1950 */ 1951 fpe = 0; 1952 } else if (is_floating_overflow(t, v->u.floating)) { 1953 /* operator '%s' produces floating point overflow */ 1954 warning(142, op_name(tn->tn_op)); 1955 v->u.floating = floating_error_value(t, v->u.floating); 1956 fpe = 0; 1957 } 1958 1959 return build_constant(tn->tn_type, v); 1960 } 1961 1962 static void 1963 use(const tnode_t *tn) 1964 { 1965 if (tn == NULL) 1966 return; 1967 switch (tn->tn_op) { 1968 case NAME: 1969 mark_as_used(tn->u.sym, false /* XXX */, false /* XXX */); 1970 break; 1971 case CON: 1972 case STRING: 1973 break; 1974 case CALL:; 1975 const function_call *call = tn->u.call; 1976 for (size_t i = 0, n = call->args_len; i < n; i++) 1977 use(call->args[i]); 1978 break; 1979 default: 1980 lint_assert(has_operands(tn)); 1981 use(tn->u.ops.left); 1982 if (is_binary(tn)) 1983 use(tn->u.ops.right); 1984 } 1985 } 1986 1987 /* 1988 * Create a tree node for a binary operator and its two operands. Also called 1989 * for unary operators; in that case rn is NULL. 1990 * 1991 * Function calls, sizeof and casts are handled elsewhere. 1992 */ 1993 tnode_t * 1994 build_binary(tnode_t *ln, op_t op, bool sys, tnode_t *rn) 1995 { 1996 const mod_t *mp = &modtab[op]; 1997 1998 /* If there was an error in one of the operands, return. */ 1999 if (ln == NULL || (mp->m_binary && rn == NULL)) 2000 return NULL; 2001 2002 if (mp->m_value_context || mp->m_compares_with_zero) 2003 ln = cconv(ln); 2004 if (mp->m_binary && op != ARROW && op != POINT) 2005 rn = cconv(rn); 2006 2007 if (mp->m_comparison) 2008 check_integer_comparison(op, ln, rn); 2009 2010 if (mp->m_value_context || mp->m_compares_with_zero) 2011 ln = promote(op, false, ln); 2012 if (mp->m_binary && op != ARROW && op != POINT && 2013 op != ASSIGN && op != RETURN && op != INIT) 2014 rn = promote(op, false, rn); 2015 2016 if (mp->m_warn_if_left_unsigned_in_c90 && 2017 ln->tn_op == CON && ln->u.value.v_unsigned_since_c90) { 2018 /* C90 treats constant as unsigned, op '%s' */ 2019 warning(218, op_name(op)); 2020 ln->u.value.v_unsigned_since_c90 = false; 2021 } 2022 if (mp->m_warn_if_right_unsigned_in_c90 && 2023 rn->tn_op == CON && rn->u.value.v_unsigned_since_c90) { 2024 /* C90 treats constant as unsigned, op '%s' */ 2025 warning(218, op_name(op)); 2026 rn->u.value.v_unsigned_since_c90 = false; 2027 } 2028 2029 if (mp->m_balance_operands || (!allow_c90 && (op == SHL || op == SHR))) 2030 balance(op, &ln, &rn); 2031 2032 if (!typeok(op, NULL, 0, ln, rn)) 2033 return NULL; 2034 2035 tnode_t *ntn; 2036 switch (op) { 2037 case POINT: 2038 case ARROW: 2039 ntn = build_struct_access(op, sys, ln, rn); 2040 break; 2041 case INCAFT: 2042 case DECAFT: 2043 case INCBEF: 2044 case DECBEF: 2045 ntn = build_prepost_incdec(op, sys, ln); 2046 break; 2047 case ADDR: 2048 ntn = build_address(sys, ln); 2049 break; 2050 case INDIR: 2051 ntn = build_op(INDIR, sys, ln->tn_type->t_subt, ln, NULL); 2052 break; 2053 case PLUS: 2054 case MINUS: 2055 ntn = build_plus_minus(op, sys, ln, rn); 2056 break; 2057 case SHL: 2058 case SHR: 2059 ntn = build_bit_shift(op, sys, ln, rn); 2060 break; 2061 case COLON: 2062 ntn = build_colon(sys, ln, rn); 2063 break; 2064 case ASSIGN: 2065 case MULASS: 2066 case DIVASS: 2067 case MODASS: 2068 case ADDASS: 2069 case SUBASS: 2070 case SHLASS: 2071 case SHRASS: 2072 case ANDASS: 2073 case XORASS: 2074 case ORASS: 2075 case RETURN: 2076 case INIT: 2077 ntn = build_assignment(op, sys, ln, rn); 2078 break; 2079 case COMMA: 2080 /* comma operator with types '%s' and '%s' */ 2081 query_message(12, 2082 type_name(ln->tn_type), type_name(rn->tn_type)); 2083 /* FALLTHROUGH */ 2084 case QUEST: 2085 ntn = build_op(op, sys, rn->tn_type, ln, rn); 2086 break; 2087 case REAL: 2088 case IMAG: 2089 ntn = build_real_imag(op, sys, ln); 2090 break; 2091 default: 2092 lint_assert(mp->m_binary == (rn != NULL)); 2093 if ((op == NOT || op == LOGAND || op == LOGOR) 2094 && ln->tn_op == ASSIGN && ln->u.ops.right->tn_op == CON) { 2095 /* constant assignment of type '%s' in operand ... */ 2096 warning(382, type_name(ln->tn_type), op_name(op), 2097 is_nonzero_val(&ln->u.ops.right->u.value) 2098 ? "true" : "false"); 2099 } 2100 if ((op == LOGAND || op == LOGOR) 2101 && rn->tn_op == ASSIGN && rn->u.ops.right->tn_op == CON) { 2102 /* constant assignment of type '%s' in operand ... */ 2103 warning(382, type_name(rn->tn_type), op_name(op), 2104 is_nonzero_val(&rn->u.ops.right->u.value) 2105 ? "true" : "false"); 2106 } 2107 type_t *rettp = mp->m_returns_bool 2108 ? gettyp(Tflag ? BOOL : INT) : ln->tn_type; 2109 ntn = build_op(op, sys, rettp, ln, rn); 2110 break; 2111 } 2112 2113 if (ntn == NULL) 2114 return NULL; 2115 2116 if (mp->m_possible_precedence_confusion) 2117 check_precedence_confusion(ntn); 2118 2119 if (mp->m_fold_constant_operands && ln->tn_op == CON) { 2120 if (!mp->m_binary || rn->tn_op == CON) { 2121 if (mp->m_compares_with_zero) 2122 ntn = fold_constant_compare_zero(ntn); 2123 else if (is_floating(ntn->tn_type->t_tspec)) 2124 ntn = fold_constant_floating(ntn); 2125 else 2126 ntn = fold_constant_integer(ntn); 2127 } else if (op == QUEST) { 2128 lint_assert(has_operands(rn)); 2129 use(ln->u.value.u.integer != 0 2130 ? rn->u.ops.right : rn->u.ops.left); 2131 ntn = ln->u.value.u.integer != 0 2132 ? rn->u.ops.left : rn->u.ops.right; 2133 } 2134 } 2135 2136 return ntn; 2137 } 2138 2139 tnode_t * 2140 build_unary(op_t op, bool sys, tnode_t *tn) 2141 { 2142 return build_binary(tn, op, sys, NULL); 2143 } 2144 2145 static bool 2146 are_members_compatible(const sym_t *a, const sym_t *b) 2147 { 2148 if (a->u.s_member.sm_offset_in_bits != b->u.s_member.sm_offset_in_bits) 2149 return false; 2150 2151 const type_t *atp = a->s_type; 2152 const type_t *btp = b->s_type; 2153 bool w = false; 2154 if (!types_compatible(atp, btp, false, false, &w) && !w) 2155 return false; 2156 if (a->s_bitfield != b->s_bitfield) 2157 return false; 2158 if (a->s_bitfield) { 2159 if (atp->t_bit_field_width != btp->t_bit_field_width) 2160 return false; 2161 if (atp->t_bit_field_offset != btp->t_bit_field_offset) 2162 return false; 2163 } 2164 return true; 2165 } 2166 2167 /* 2168 * Return whether all struct/union members with the same name have the same 2169 * type and offset. 2170 */ 2171 static bool 2172 all_members_compatible(const sym_t *msym) 2173 { 2174 for (const sym_t *csym = msym; 2175 csym != NULL; csym = csym->s_symtab_next) { 2176 if (!is_member(csym)) 2177 continue; 2178 if (strcmp(msym->s_name, csym->s_name) != 0) 2179 continue; 2180 2181 for (const sym_t *sym = csym->s_symtab_next; 2182 sym != NULL; sym = sym->s_symtab_next) { 2183 if (is_member(sym) 2184 && strcmp(csym->s_name, sym->s_name) == 0 2185 && !are_members_compatible(csym, sym)) 2186 return false; 2187 } 2188 } 2189 return true; 2190 } 2191 2192 sym_t * 2193 find_member(const struct_or_union *sou, const char *name) 2194 { 2195 for (sym_t *mem = sou->sou_first_member; 2196 mem != NULL; mem = mem->s_next) { 2197 lint_assert(is_member(mem)); 2198 lint_assert(mem->u.s_member.sm_containing_type == sou); 2199 if (strcmp(mem->s_name, name) == 0) 2200 return mem; 2201 } 2202 2203 for (sym_t *mem = sou->sou_first_member; 2204 mem != NULL; mem = mem->s_next) { 2205 if (is_struct_or_union(mem->s_type->t_tspec) 2206 && mem->s_name == unnamed) { 2207 sym_t *nested_mem = 2208 find_member(mem->s_type->u.sou, name); 2209 if (nested_mem != NULL) 2210 return nested_mem; 2211 } 2212 } 2213 return NULL; 2214 } 2215 2216 /* 2217 * Remove the member if it was unknown until now, which means 2218 * that no defined struct or union has a member with the same name. 2219 */ 2220 static void 2221 remove_unknown_member(tnode_t *tn, sym_t *msym) 2222 { 2223 /* type '%s' does not have member '%s' */ 2224 error(101, type_name(tn->tn_type), msym->s_name); 2225 symtab_remove_forever(msym); 2226 msym->s_kind = SK_MEMBER; 2227 msym->s_scl = STRUCT_MEMBER; 2228 2229 struct_or_union *sou = expr_zero_alloc(sizeof(*sou), 2230 "struct_or_union"); 2231 sou->sou_tag = expr_zero_alloc(sizeof(*sou->sou_tag), "sym"); 2232 sou->sou_tag->s_name = unnamed; 2233 2234 msym->u.s_member.sm_containing_type = sou; 2235 /* 2236 * The member sm_offset_in_bits is not needed here since this symbol 2237 * can only be used for error reporting. 2238 */ 2239 } 2240 2241 /* 2242 * Returns a symbol which has the same name as 'msym' and is a member of the 2243 * struct or union specified by 'tn'. 2244 */ 2245 static sym_t * 2246 struct_or_union_member(tnode_t *tn, op_t op, sym_t *msym) 2247 { 2248 2249 /* Determine the tag type of which msym is expected to be a member. */ 2250 const type_t *tp = NULL; 2251 if (op == POINT && is_struct_or_union(tn->tn_type->t_tspec)) 2252 tp = tn->tn_type; 2253 if (op == ARROW && tn->tn_type->t_tspec == PTR 2254 && is_struct_or_union(tn->tn_type->t_subt->t_tspec)) 2255 tp = tn->tn_type->t_subt; 2256 struct_or_union *sou = tp != NULL ? tp->u.sou : NULL; 2257 2258 if (sou != NULL) { 2259 sym_t *nested_mem = find_member(sou, msym->s_name); 2260 if (nested_mem != NULL) 2261 return nested_mem; 2262 } 2263 2264 if (msym->s_scl == NO_SCL) { 2265 remove_unknown_member(tn, msym); 2266 return msym; 2267 } 2268 2269 bool eq = all_members_compatible(msym); 2270 2271 /* 2272 * Now handle the case in which the left operand refers really to a 2273 * struct/union, but the right operand is not member of it. 2274 */ 2275 if (sou != NULL) { 2276 if (eq && !allow_c90) 2277 /* invalid use of member '%s' */ 2278 warning(102, msym->s_name); 2279 else 2280 /* invalid use of member '%s' */ 2281 error(102, msym->s_name); 2282 return msym; 2283 } 2284 2285 if (eq) { 2286 if (op == POINT) { 2287 if (!allow_c90) 2288 /* left operand of '.' must be struct ... */ 2289 warning(103, type_name(tn->tn_type)); 2290 else 2291 /* left operand of '.' must be struct ... */ 2292 error(103, type_name(tn->tn_type)); 2293 } else { 2294 if (!allow_c90 && tn->tn_type->t_tspec == PTR) 2295 /* left operand of '->' must be pointer ... */ 2296 warning(104, type_name(tn->tn_type)); 2297 else 2298 /* left operand of '->' must be pointer ... */ 2299 error(104, type_name(tn->tn_type)); 2300 } 2301 } else { 2302 if (!allow_c90) 2303 /* non-unique member requires struct/union %s */ 2304 error(105, op == POINT ? "object" : "pointer"); 2305 else 2306 /* unacceptable operand of '%s' */ 2307 error(111, op_name(op)); 2308 } 2309 2310 return msym; 2311 } 2312 2313 tnode_t * 2314 build_member_access(tnode_t *ln, op_t op, bool sys, sbuf_t *member) 2315 { 2316 sym_t *msym; 2317 2318 if (ln == NULL) 2319 return NULL; 2320 2321 if (op == ARROW) 2322 /* must do this before struct_or_union_member is called */ 2323 ln = cconv(ln); 2324 msym = struct_or_union_member(ln, op, getsym(member)); 2325 return build_binary(ln, op, sys, build_name(msym, false)); 2326 } 2327 2328 /* 2329 * Perform class conversions. 2330 * 2331 * Arrays of type T are converted into pointers to type T. 2332 * Functions are converted to pointers to functions. 2333 * Lvalues are converted to rvalues. 2334 * 2335 * C99 6.3 "Conversions" 2336 * C99 6.3.2 "Other operands" 2337 * C99 6.3.2.1 "Lvalues, arrays, and function designators" 2338 */ 2339 tnode_t * 2340 cconv(tnode_t *tn) 2341 { 2342 if (tn->tn_type->t_tspec == ARRAY) { 2343 if (!tn->tn_lvalue) { 2344 /* XXX print correct operator */ 2345 /* %soperand of '%s' must be lvalue */ 2346 gnuism(114, "", op_name(ADDR)); 2347 } 2348 tn = build_op(ADDR, tn->tn_sys, 2349 expr_derive_type(tn->tn_type->t_subt, PTR), tn, NULL); 2350 } 2351 2352 if (tn->tn_type->t_tspec == FUNC) 2353 tn = build_address(tn->tn_sys, tn); 2354 2355 if (tn->tn_lvalue) { 2356 type_t *tp = expr_dup_type(tn->tn_type); 2357 /* C99 6.3.2.1p2 sentence 2 says to remove the qualifiers. */ 2358 tp->t_const = tp->t_volatile = false; 2359 tn = build_op(LOAD, tn->tn_sys, tp, tn, NULL); 2360 } 2361 2362 return tn; 2363 } 2364 2365 const tnode_t * 2366 before_conversion(const tnode_t *tn) 2367 { 2368 while (tn->tn_op == CVT && !tn->tn_cast) 2369 tn = tn->u.ops.left; 2370 return tn; 2371 } 2372 2373 /* 2374 * Most errors required by C90 are reported in struct_or_union_member(). 2375 * Here we only check for totally wrong things. 2376 */ 2377 static bool 2378 typeok_point(const tnode_t *ln, const type_t *ltp, tspec_t lt) 2379 { 2380 if (is_struct_or_union(lt)) 2381 return true; 2382 2383 if (lt == FUNC || lt == VOID || ltp->t_bitfield) 2384 goto wrong; 2385 2386 /* 2387 * Some C dialects from before C90 tolerated any lvalue on the 2388 * left-hand side of the '.' operator, allowing things like 'char 2389 * st[100]; st.st_mtime', assuming that the member 'st_mtime' only 2390 * occurred in a single struct; see typeok_arrow. 2391 */ 2392 if (ln->tn_lvalue) 2393 return true; 2394 2395 wrong: 2396 /* With allow_c90 we already got an error */ 2397 if (!allow_c90) 2398 /* unacceptable operand of '%s' */ 2399 error(111, op_name(POINT)); 2400 2401 return false; 2402 } 2403 2404 static bool 2405 typeok_arrow(tspec_t lt) 2406 { 2407 /* 2408 * C1978 Appendix A 14.1 says: <quote>In fact, any lvalue is allowed 2409 * before '.', and that lvalue is then assumed to have the form of the 2410 * structure of which the name of the right is a member. [...] Such 2411 * constructions are non-portable.</quote> 2412 */ 2413 if (lt == PTR || (!allow_c90 && is_integer(lt))) 2414 return true; 2415 2416 /* With allow_c90 we already got an error */ 2417 if (!allow_c90) 2418 /* unacceptable operand of '%s' */ 2419 error(111, op_name(ARROW)); 2420 return false; 2421 } 2422 2423 static bool 2424 typeok_incdec(op_t op, const tnode_t *tn, const type_t *tp) 2425 { 2426 /* operand has scalar type (checked in typeok) */ 2427 if (!tn->tn_lvalue) { 2428 if (tn->tn_op == CVT && tn->tn_cast && 2429 tn->u.ops.left->tn_op == LOAD) 2430 /* a cast does not yield an lvalue */ 2431 error(163); 2432 /* %soperand of '%s' must be lvalue */ 2433 error(114, "", op_name(op)); 2434 return false; 2435 } 2436 if (tp->t_const && allow_c90) 2437 /* %soperand of '%s' must be modifiable lvalue */ 2438 warning(115, "", op_name(op)); 2439 return true; 2440 } 2441 2442 static bool 2443 typeok_address(op_t op, const tnode_t *tn, const type_t *tp, tspec_t t) 2444 { 2445 if (t == ARRAY || t == FUNC) { 2446 /* ok, a warning comes later (in build_address()) */ 2447 } else if (!tn->tn_lvalue) { 2448 if (tn->tn_op == CVT && tn->tn_cast && 2449 tn->u.ops.left->tn_op == LOAD) 2450 /* a cast does not yield an lvalue */ 2451 error(163); 2452 /* %soperand of '%s' must be lvalue */ 2453 error(114, "", op_name(op)); 2454 return false; 2455 } else if (is_scalar(t)) { 2456 if (tp->t_bitfield) { 2457 /* cannot take address of bit-field */ 2458 error(112); 2459 return false; 2460 } 2461 } else if (t != STRUCT && t != UNION) { 2462 /* unacceptable operand of '%s' */ 2463 error(111, op_name(op)); 2464 return false; 2465 } 2466 if (tn->tn_op == NAME && tn->u.sym->s_register) { 2467 /* cannot take address of register '%s' */ 2468 error(113, tn->u.sym->s_name); 2469 return false; 2470 } 2471 return true; 2472 } 2473 2474 static bool 2475 typeok_indir(const type_t *tp, tspec_t t) 2476 { 2477 2478 if (t != PTR) { 2479 /* cannot dereference non-pointer type '%s' */ 2480 error(96, type_name(tp)); 2481 return false; 2482 } 2483 return true; 2484 } 2485 2486 static void 2487 warn_incompatible_types(op_t op, 2488 const type_t *ltp, tspec_t lt, 2489 const type_t *rtp, tspec_t rt) 2490 { 2491 bool binary = modtab[op].m_binary; 2492 2493 if (lt == VOID || (binary && rt == VOID)) { 2494 /* void type invalid in expression */ 2495 error(109); 2496 } else if (op == ASSIGN) 2497 /* cannot assign to '%s' from '%s' */ 2498 error(171, type_name(ltp), type_name(rtp)); 2499 else if (binary) 2500 /* operands of '%s' have incompatible types '%s' and '%s' */ 2501 error(107, op_name(op), type_name(ltp), type_name(rtp)); 2502 else { 2503 lint_assert(rt == NO_TSPEC); 2504 /* operand of '%s' has invalid type '%s' */ 2505 error(108, op_name(op), type_name(ltp)); 2506 } 2507 } 2508 2509 static bool 2510 typeok_plus(op_t op, 2511 const type_t *ltp, tspec_t lt, 2512 const type_t *rtp, tspec_t rt) 2513 { 2514 /* operands have scalar types (checked in typeok) */ 2515 if ((lt == PTR && !is_integer(rt)) || (rt == PTR && !is_integer(lt))) { 2516 warn_incompatible_types(op, ltp, lt, rtp, rt); 2517 return false; 2518 } 2519 return true; 2520 } 2521 2522 static bool 2523 typeok_minus(op_t op, 2524 const type_t *ltp, tspec_t lt, 2525 const type_t *rtp, tspec_t rt) 2526 { 2527 /* operands have scalar types (checked in typeok) */ 2528 if ((lt == PTR && rt != PTR && !is_integer(rt)) || 2529 (lt != PTR && rt == PTR)) { 2530 warn_incompatible_types(op, ltp, lt, rtp, rt); 2531 return false; 2532 } 2533 if (lt == PTR && rt == PTR && 2534 !types_compatible(ltp->t_subt, rtp->t_subt, true, false, NULL)) { 2535 /* invalid pointer subtraction */ 2536 error(116); 2537 } 2538 return true; 2539 } 2540 2541 static void 2542 typeok_shr(op_t op, 2543 const tnode_t *ln, tspec_t lt, 2544 const tnode_t *rn, tspec_t rt) 2545 { 2546 tspec_t olt = before_conversion(ln)->tn_type->t_tspec; 2547 tspec_t ort = before_conversion(rn)->tn_type->t_tspec; 2548 2549 /* operands have integer types (checked in typeok) */ 2550 if (pflag && !is_uinteger(olt)) { 2551 integer_constraints lc = ic_expr(ln); 2552 if (lc.bclr >> 63 != 0) 2553 return; 2554 2555 if (ln->tn_op != CON) 2556 /* bitwise '%s' on signed value possibly nonportable */ 2557 warning(117, op_name(op)); 2558 else if (ln->u.value.u.integer < 0) 2559 /* bitwise '%s' on signed value nonportable */ 2560 warning(120, op_name(op)); 2561 } else if (allow_trad && allow_c90 && 2562 !is_uinteger(olt) && is_uinteger(ort)) { 2563 /* The left operand would become unsigned in traditional C. */ 2564 if (hflag && (ln->tn_op != CON || ln->u.value.u.integer < 0)) { 2565 /* semantics of '%s' change in C90; use ... */ 2566 warning(118, op_name(op)); 2567 } 2568 } else if (allow_trad && allow_c90 && 2569 !is_uinteger(olt) && !is_uinteger(ort) && 2570 portable_rank_cmp(lt, rt) < 0) { 2571 /* 2572 * In traditional C, the left operand would be extended 2573 * (possibly sign-extended) and then shifted. 2574 */ 2575 if (hflag && (ln->tn_op != CON || ln->u.value.u.integer < 0)) { 2576 /* semantics of '%s' change in C90; use ... */ 2577 warning(118, op_name(op)); 2578 } 2579 } 2580 } 2581 2582 static void 2583 typeok_shl(op_t op, tspec_t lt, tspec_t rt) 2584 { 2585 /* 2586 * C90 does not perform balancing for shift operations, but traditional 2587 * C does. If the width of the right operand is greater than the width 2588 * of the left operand, then in traditional C the left operand would be 2589 * extended to the width of the right operand. For SHL this may result 2590 * in different results. 2591 */ 2592 if (portable_rank_cmp(lt, rt) < 0) { 2593 /* 2594 * XXX If both operands are constant, make sure that there is 2595 * really a difference between C90 and traditional C. 2596 */ 2597 if (hflag && allow_trad && allow_c90) 2598 /* semantics of '%s' change in C90; use ... */ 2599 warning(118, op_name(op)); 2600 } 2601 } 2602 2603 static void 2604 typeok_shift(const type_t *ltp, tspec_t lt, const tnode_t *rn, tspec_t rt) 2605 { 2606 if (rn->tn_op != CON) 2607 return; 2608 2609 if (!is_uinteger(rt) && rn->u.value.u.integer < 0) 2610 /* negative shift */ 2611 warning(121); 2612 else if ((uint64_t)rn->u.value.u.integer == size_in_bits(lt)) 2613 /* shift amount %u equals bit-size of '%s' */ 2614 warning(267, (unsigned)rn->u.value.u.integer, type_name(ltp)); 2615 else if ((uint64_t)rn->u.value.u.integer > size_in_bits(lt)) { 2616 /* shift amount %llu is greater than bit-size %llu of '%s' */ 2617 warning(122, (unsigned long long)rn->u.value.u.integer, 2618 (unsigned long long)size_in_bits(lt), 2619 tspec_name(lt)); 2620 } 2621 } 2622 2623 static bool 2624 is_typeok_eq(const tnode_t *ln, tspec_t lt, const tnode_t *rn, tspec_t rt) 2625 { 2626 if (lt == PTR && is_null_pointer(rn)) 2627 return true; 2628 if (rt == PTR && is_null_pointer(ln)) 2629 return true; 2630 return false; 2631 } 2632 2633 static void 2634 warn_incompatible_pointers(op_t op, const type_t *ltp, const type_t *rtp) 2635 { 2636 lint_assert(ltp->t_tspec == PTR); 2637 lint_assert(rtp->t_tspec == PTR); 2638 2639 tspec_t lt = ltp->t_subt->t_tspec; 2640 tspec_t rt = rtp->t_subt->t_tspec; 2641 2642 if (is_struct_or_union(lt) && is_struct_or_union(rt)) { 2643 if (op == RETURN) 2644 /* invalid structure pointer combination */ 2645 warning(244); 2646 else { 2647 /* incompatible structure pointers: '%s' '%s' '%s' */ 2648 warning(245, type_name(ltp), 2649 op_name(op), type_name(rtp)); 2650 } 2651 } else { 2652 if (op == RETURN) 2653 /* invalid combination of '%s' and '%s' */ 2654 warning(184, type_name(ltp), type_name(rtp)); 2655 else { 2656 /* invalid combination of '%s' and '%s', op '%s' */ 2657 warning(124, 2658 type_name(ltp), type_name(rtp), op_name(op)); 2659 } 2660 } 2661 } 2662 2663 static void 2664 check_pointer_comparison(op_t op, const tnode_t *ln, const tnode_t *rn) 2665 { 2666 type_t *ltp = ln->tn_type, *rtp = rn->tn_type; 2667 tspec_t lst = ltp->t_subt->t_tspec, rst = rtp->t_subt->t_tspec; 2668 2669 if (lst == VOID || rst == VOID) { 2670 /* TODO: C99 behaves like C90 here. */ 2671 if (!allow_trad && !allow_c99 && 2672 (lst == FUNC || rst == FUNC)) { 2673 /* (void *)0 is already handled in typeok() */ 2674 const char *lsts, *rsts; 2675 *(lst == FUNC ? &lsts : &rsts) = "function pointer"; 2676 *(lst == VOID ? &lsts : &rsts) = "'void *'"; 2677 /* C90 or later forbid comparison of %s with %s */ 2678 warning(274, lsts, rsts); 2679 } 2680 return; 2681 } 2682 2683 if (!types_compatible(ltp->t_subt, rtp->t_subt, true, false, NULL)) { 2684 warn_incompatible_pointers(op, ltp, rtp); 2685 return; 2686 } 2687 2688 if (lst == FUNC && rst == FUNC) { 2689 /* TODO: C99 behaves like C90 here, see C99 6.5.8p2. */ 2690 if (!allow_trad && !allow_c99 && op != EQ && op != NE) 2691 /* pointers to functions can only be compared ... */ 2692 warning(125); 2693 } 2694 } 2695 2696 static bool 2697 typeok_compare(op_t op, 2698 const tnode_t *ln, const type_t *ltp, tspec_t lt, 2699 const tnode_t *rn, const type_t *rtp, tspec_t rt) 2700 { 2701 if (lt == PTR && rt == PTR) { 2702 check_pointer_comparison(op, ln, rn); 2703 return true; 2704 } 2705 2706 if (lt != PTR && rt != PTR) 2707 return true; 2708 2709 if (!is_integer(lt) && !is_integer(rt)) { 2710 warn_incompatible_types(op, ltp, lt, rtp, rt); 2711 return false; 2712 } 2713 2714 const char *lx = lt == PTR ? "pointer" : "integer"; 2715 const char *rx = rt == PTR ? "pointer" : "integer"; 2716 /* invalid combination of %s '%s' and %s '%s', op '%s' */ 2717 warning(123, lx, type_name(ltp), rx, type_name(rtp), op_name(op)); 2718 return true; 2719 } 2720 2721 static bool 2722 typeok_quest(tspec_t lt, const tnode_t *rn) 2723 { 2724 if (!is_scalar(lt)) { 2725 /* first operand of '?' must have scalar type */ 2726 error(170); 2727 return false; 2728 } 2729 lint_assert(before_conversion(rn)->tn_op == COLON); 2730 return true; 2731 } 2732 2733 static void 2734 typeok_colon_pointer(const type_t *ltp, const type_t *rtp) 2735 { 2736 type_t *lstp = ltp->t_subt; 2737 type_t *rstp = rtp->t_subt; 2738 tspec_t lst = lstp->t_tspec; 2739 tspec_t rst = rstp->t_tspec; 2740 2741 if ((lst == VOID && rst == FUNC) || (lst == FUNC && rst == VOID)) { 2742 /* (void *)0 is handled in typeok_colon */ 2743 /* TODO: C99 behaves like C90 here. */ 2744 if (!allow_trad && !allow_c99) 2745 /* conversion of %s to %s requires a cast, op %s */ 2746 warning(305, "function pointer", "'void *'", 2747 op_name(COLON)); 2748 return; 2749 } 2750 2751 if (pointer_types_are_compatible(lstp, rstp, true)) 2752 return; 2753 if (!types_compatible(lstp, rstp, true, false, NULL)) 2754 warn_incompatible_pointers(COLON, ltp, rtp); 2755 } 2756 2757 static bool 2758 typeok_colon(const tnode_t *ln, const type_t *ltp, tspec_t lt, 2759 const tnode_t *rn, const type_t *rtp, tspec_t rt) 2760 { 2761 2762 if (is_arithmetic(lt) && is_arithmetic(rt)) 2763 return true; 2764 if (lt == BOOL && rt == BOOL) 2765 return true; 2766 2767 if (lt == STRUCT && rt == STRUCT && ltp->u.sou == rtp->u.sou) 2768 return true; 2769 if (lt == UNION && rt == UNION && ltp->u.sou == rtp->u.sou) 2770 return true; 2771 2772 if (lt == PTR && is_null_pointer(rn)) 2773 return true; 2774 if (rt == PTR && is_null_pointer(ln)) 2775 return true; 2776 2777 if ((lt == PTR && is_integer(rt)) || (is_integer(lt) && rt == PTR)) { 2778 const char *lx = lt == PTR ? "pointer" : "integer"; 2779 const char *rx = rt == PTR ? "pointer" : "integer"; 2780 /* invalid combination of %s '%s' and %s '%s', op '%s' */ 2781 warning(123, lx, type_name(ltp), 2782 rx, type_name(rtp), op_name(COLON)); 2783 return true; 2784 } 2785 2786 if (lt == VOID || rt == VOID) { 2787 if (lt != VOID || rt != VOID) 2788 /* incompatible types '%s' and '%s' in conditional */ 2789 warning(126, type_name(ltp), type_name(rtp)); 2790 return true; 2791 } 2792 2793 if (lt == PTR && rt == PTR) { 2794 typeok_colon_pointer(ltp, rtp); 2795 return true; 2796 } 2797 2798 /* incompatible types '%s' and '%s' in conditional */ 2799 error(126, type_name(ltp), type_name(rtp)); 2800 return false; 2801 } 2802 2803 static bool 2804 has_constant_member(const type_t *tp) 2805 { 2806 lint_assert(is_struct_or_union(tp->t_tspec)); 2807 2808 for (sym_t *m = tp->u.sou->sou_first_member; 2809 m != NULL; m = m->s_next) { 2810 const type_t *mtp = m->s_type; 2811 if (mtp->t_const) 2812 return true; 2813 if (is_struct_or_union(mtp->t_tspec) && 2814 has_constant_member(mtp)) 2815 return true; 2816 } 2817 return false; 2818 } 2819 2820 static bool 2821 typeok_assign(op_t op, const tnode_t *ln, const type_t *ltp, tspec_t lt) 2822 { 2823 if (op == RETURN || op == INIT || op == FARG) 2824 return true; 2825 2826 if (!ln->tn_lvalue) { 2827 if (ln->tn_op == CVT && ln->tn_cast && 2828 ln->u.ops.left->tn_op == LOAD) 2829 /* a cast does not yield an lvalue */ 2830 error(163); 2831 /* %soperand of '%s' must be lvalue */ 2832 error(114, "left ", op_name(op)); 2833 return false; 2834 } else if (ltp->t_const 2835 || (is_struct_or_union(lt) && has_constant_member(ltp))) { 2836 if (allow_c90) 2837 /* %soperand of '%s' must be modifiable lvalue */ 2838 warning(115, "left ", op_name(op)); 2839 } 2840 return true; 2841 } 2842 2843 static bool 2844 typeok_scalar(op_t op, const mod_t *mp, 2845 const type_t *ltp, tspec_t lt, 2846 const type_t *rtp, tspec_t rt) 2847 { 2848 if (mp->m_takes_bool && lt == BOOL && rt == BOOL) 2849 return true; 2850 if (mp->m_requires_integer) { 2851 if (!is_integer(lt) || (mp->m_binary && !is_integer(rt))) { 2852 warn_incompatible_types(op, ltp, lt, rtp, rt); 2853 return false; 2854 } 2855 } else if (mp->m_requires_integer_or_complex) { 2856 if ((!is_integer(lt) && !is_complex(lt)) || 2857 (mp->m_binary && (!is_integer(rt) && !is_complex(rt)))) { 2858 warn_incompatible_types(op, ltp, lt, rtp, rt); 2859 return false; 2860 } 2861 } else if (mp->m_requires_scalar) { 2862 if (!is_scalar(lt) || (mp->m_binary && !is_scalar(rt))) { 2863 warn_incompatible_types(op, ltp, lt, rtp, rt); 2864 return false; 2865 } 2866 } else if (mp->m_requires_arith) { 2867 if (!is_arithmetic(lt) || 2868 (mp->m_binary && !is_arithmetic(rt))) { 2869 warn_incompatible_types(op, ltp, lt, rtp, rt); 2870 return false; 2871 } 2872 } 2873 return true; 2874 } 2875 2876 static void 2877 check_assign_void_pointer(op_t op, int arg, 2878 tspec_t lt, tspec_t lst, 2879 tspec_t rt, tspec_t rst) 2880 { 2881 2882 if (!(lt == PTR && rt == PTR && (lst == VOID || rst == VOID))) 2883 return; 2884 /* two pointers, at least one pointer to void */ 2885 2886 /* TODO: C99 behaves like C90 here. */ 2887 if (!(!allow_trad && !allow_c99 && (lst == FUNC || rst == FUNC))) 2888 return; 2889 /* comb. of ptr to func and ptr to void */ 2890 2891 const char *lts, *rts; 2892 *(lst == FUNC ? <s : &rts) = "function pointer"; 2893 *(lst == VOID ? <s : &rts) = "'void *'"; 2894 2895 switch (op) { 2896 case INIT: 2897 case RETURN: 2898 /* conversion of %s to %s requires a cast */ 2899 warning(303, rts, lts); 2900 break; 2901 case FARG: 2902 /* conversion of %s to %s requires a cast, arg #%d */ 2903 warning(304, rts, lts, arg); 2904 break; 2905 default: 2906 /* conversion of %s to %s requires a cast, op %s */ 2907 warning(305, rts, lts, op_name(op)); 2908 break; 2909 } 2910 } 2911 2912 static bool 2913 is_direct_function_call(const tnode_t *tn, const char **out_name) 2914 { 2915 2916 if (tn->tn_op == CALL 2917 && tn->u.call->func->tn_op == ADDR 2918 && tn->u.call->func->u.ops.left->tn_op == NAME) { 2919 *out_name = tn->u.call->func->u.ops.left->u.sym->s_name; 2920 return true; 2921 } 2922 return false; 2923 } 2924 2925 static bool 2926 is_unconst_function(const char *name) 2927 { 2928 2929 return strcmp(name, "memchr") == 0 || 2930 strcmp(name, "strchr") == 0 || 2931 strcmp(name, "strpbrk") == 0 || 2932 strcmp(name, "strrchr") == 0 || 2933 strcmp(name, "strstr") == 0; 2934 } 2935 2936 static bool 2937 is_const_char_pointer(const tnode_t *tn) 2938 { 2939 /* 2940 * For traditional reasons, C99 6.4.5p5 defines that string literals 2941 * have type 'char[]'. They are often implicitly converted to 'char 2942 * *', for example when they are passed as function arguments. 2943 * 2944 * C99 6.4.5p6 further defines that modifying a string that is 2945 * constructed from a string literal invokes undefined behavior. 2946 * 2947 * Out of these reasons, string literals are treated as 'effectively 2948 * const' here. 2949 */ 2950 if (tn->tn_op == CVT && 2951 tn->u.ops.left->tn_op == ADDR && 2952 tn->u.ops.left->u.ops.left->tn_op == STRING) 2953 return true; 2954 2955 const type_t *tp = before_conversion(tn)->tn_type; 2956 return tp->t_tspec == PTR && 2957 tp->t_subt->t_tspec == CHAR && 2958 tp->t_subt->t_const; 2959 } 2960 2961 static bool 2962 is_const_pointer(const tnode_t *tn) 2963 { 2964 const type_t *tp = before_conversion(tn)->tn_type; 2965 return tp->t_tspec == PTR && tp->t_subt->t_const; 2966 } 2967 2968 static void 2969 check_unconst_function(const type_t *lstp, const tnode_t *rn) 2970 { 2971 const char *function_name; 2972 2973 if (lstp->t_tspec == CHAR && !lstp->t_const && 2974 is_direct_function_call(rn, &function_name) && 2975 is_unconst_function(function_name) && 2976 rn->u.call->args_len >= 1 && 2977 is_const_char_pointer(rn->u.call->args[0])) { 2978 /* call to '%s' effectively discards 'const' from argument */ 2979 warning(346, function_name); 2980 } 2981 2982 if (!lstp->t_const && 2983 is_direct_function_call(rn, &function_name) && 2984 strcmp(function_name, "bsearch") == 0 && 2985 rn->u.call->args_len >= 2 && 2986 is_const_pointer(rn->u.call->args[1])) { 2987 /* call to '%s' effectively discards 'const' from argument */ 2988 warning(346, function_name); 2989 } 2990 } 2991 2992 static bool 2993 check_assign_void_pointer_compat(op_t op, const function_call *call, int arg, 2994 tspec_t lt, 2995 const type_t *lstp, tspec_t lst, 2996 const tnode_t *rn, 2997 const type_t *rtp, tspec_t rt, 2998 const type_t *rstp, tspec_t rst) 2999 { 3000 if (!(lt == PTR && rt == PTR && (lst == VOID || rst == VOID || 3001 types_compatible(lstp, rstp, 3002 true, false, NULL)))) 3003 return false; 3004 3005 /* compatible pointer types (qualifiers ignored) */ 3006 char qualifiers[32]; 3007 snprintf(qualifiers, sizeof(qualifiers), "%s%s", 3008 !lstp->t_const && rstp->t_const ? " const" : "", 3009 !lstp->t_volatile && rstp->t_volatile ? " volatile" : ""); 3010 if (allow_c90 && qualifiers[0] != '\0') { 3011 switch (op) { 3012 case INIT: 3013 case RETURN: 3014 /* '%s' discards '%s' from '%s' */ 3015 warning(182, op_name(op), 3016 qualifiers + 1, type_name(rtp)); 3017 break; 3018 case FARG: 3019 /* passing '%s' as argument %d to '%s' discards '%s' */ 3020 warning(383, type_name(rtp), arg, 3021 function_call_descr(call), qualifiers + 1); 3022 break; 3023 default: 3024 /* operator '%s' discards '%s' from '%s' */ 3025 warning(128, op_name(op), 3026 qualifiers + 1, type_name(rtp)); 3027 break; 3028 } 3029 } 3030 3031 if (allow_c90) 3032 check_unconst_function(lstp, rn); 3033 3034 return true; 3035 } 3036 3037 static bool 3038 check_assign_pointer_integer(op_t op, int arg, 3039 const type_t *ltp, tspec_t lt, 3040 const type_t *rtp, tspec_t rt) 3041 { 3042 3043 if (!((lt == PTR && is_integer(rt)) || (is_integer(lt) && rt == PTR))) 3044 return false; 3045 3046 const char *lx = lt == PTR ? "pointer" : "integer"; 3047 const char *rx = rt == PTR ? "pointer" : "integer"; 3048 3049 switch (op) { 3050 case INIT: 3051 case RETURN: 3052 /* invalid combination of %s '%s' and %s '%s' for '%s' */ 3053 warning(183, 3054 lx, type_name(ltp), rx, type_name(rtp), op_name(op)); 3055 break; 3056 case FARG: 3057 /* invalid combination of %s '%s' and %s '%s', arg #%d */ 3058 warning(154, 3059 lx, type_name(ltp), rx, type_name(rtp), arg); 3060 break; 3061 default: 3062 /* invalid combination of %s '%s' and %s '%s', op '%s' */ 3063 warning(123, 3064 lx, type_name(ltp), rx, type_name(rtp), op_name(op)); 3065 break; 3066 } 3067 return true; 3068 } 3069 3070 static bool 3071 check_assign_pointer(op_t op, int arg, 3072 const type_t *ltp, tspec_t lt, 3073 const type_t *rtp, tspec_t rt) 3074 { 3075 if (!(lt == PTR && rt == PTR)) 3076 return false; 3077 3078 if (op == FARG) 3079 /* converting '%s' to incompatible '%s' for ... */ 3080 warning(153, type_name(rtp), type_name(ltp), arg); 3081 else 3082 warn_incompatible_pointers(op, ltp, rtp); 3083 return true; 3084 } 3085 3086 static void 3087 warn_assign(op_t op, int arg, 3088 const type_t *ltp, tspec_t lt, 3089 const type_t *rtp, tspec_t rt) 3090 { 3091 switch (op) { 3092 case INIT: 3093 /* cannot initialize '%s' from '%s' */ 3094 error(185, type_name(ltp), type_name(rtp)); 3095 break; 3096 case RETURN: 3097 /* function has return type '%s' but returns '%s' */ 3098 error(211, type_name(ltp), type_name(rtp)); 3099 break; 3100 case FARG: 3101 /* passing '%s' to incompatible '%s', arg #%d */ 3102 warning(155, type_name(rtp), type_name(ltp), arg); 3103 break; 3104 default: 3105 warn_incompatible_types(op, ltp, lt, rtp, rt); 3106 break; 3107 } 3108 } 3109 3110 /* 3111 * Checks type compatibility for ASSIGN, INIT, FARG and RETURN 3112 * and prints warnings/errors if necessary. 3113 * Returns whether the types are (almost) compatible. 3114 */ 3115 static bool 3116 check_assign_types_compatible(op_t op, const function_call *call, int arg, 3117 const tnode_t *ln, const tnode_t *rn) 3118 { 3119 tspec_t lt, rt, lst = NO_TSPEC, rst = NO_TSPEC; 3120 type_t *ltp, *rtp, *lstp = NULL, *rstp = NULL; 3121 3122 if ((lt = (ltp = ln->tn_type)->t_tspec) == PTR) 3123 lst = (lstp = ltp->t_subt)->t_tspec; 3124 if ((rt = (rtp = rn->tn_type)->t_tspec) == PTR) 3125 rst = (rstp = rtp->t_subt)->t_tspec; 3126 3127 if (lt == BOOL && is_scalar(rt)) /* C99 6.3.1.2 */ 3128 return true; 3129 3130 if (is_arithmetic(lt) && (is_arithmetic(rt) || rt == BOOL)) 3131 return true; 3132 3133 if (is_struct_or_union(lt) && is_struct_or_union(rt)) 3134 return ltp->u.sou == rtp->u.sou; 3135 3136 if (lt == PTR && is_null_pointer(rn)) { 3137 if (is_integer(rn->tn_type->t_tspec)) 3138 /* implicit conversion from integer 0 to pointer ... */ 3139 query_message(15, type_name(ltp)); 3140 return true; 3141 } 3142 3143 check_assign_void_pointer(op, arg, lt, lst, rt, rst); 3144 3145 if (check_assign_void_pointer_compat(op, call, arg, 3146 lt, lstp, lst, rn, rtp, rt, rstp, rst)) 3147 return true; 3148 3149 if (check_assign_pointer_integer(op, arg, ltp, lt, rtp, rt)) 3150 return true; 3151 3152 if (check_assign_pointer(op, arg, ltp, lt, rtp, rt)) 3153 return true; 3154 3155 warn_assign(op, arg, ltp, lt, rtp, rt); 3156 return false; 3157 } 3158 3159 static bool 3160 has_side_effect(const tnode_t *tn) /* NOLINT(misc-no-recursion) */ 3161 { 3162 op_t op = tn->tn_op; 3163 3164 if (modtab[op].m_has_side_effect) 3165 return true; 3166 3167 if (op == CVT && tn->tn_type->t_tspec == VOID) 3168 return has_side_effect(tn->u.ops.left); 3169 3170 /* XXX: Why not has_side_effect(tn->u.ops.left) as well? */ 3171 if (op == LOGAND || op == LOGOR) 3172 return has_side_effect(tn->u.ops.right); 3173 3174 /* XXX: Why not has_side_effect(tn->u.ops.left) as well? */ 3175 if (op == QUEST) 3176 return has_side_effect(tn->u.ops.right); 3177 3178 if (op == COLON || op == COMMA) { 3179 return has_side_effect(tn->u.ops.left) || 3180 has_side_effect(tn->u.ops.right); 3181 } 3182 3183 return false; 3184 } 3185 3186 static bool 3187 is_void_cast(const tnode_t *tn) 3188 { 3189 3190 return tn->tn_op == CVT && tn->tn_cast && 3191 tn->tn_type->t_tspec == VOID; 3192 } 3193 3194 static bool 3195 is_local_symbol(const tnode_t *tn) 3196 { 3197 3198 return tn->tn_op == LOAD && 3199 tn->u.ops.left->tn_op == NAME && 3200 tn->u.ops.left->u.sym->s_scl == AUTO; 3201 } 3202 3203 static bool 3204 is_int_constant_zero(const tnode_t *tn) 3205 { 3206 3207 return tn->tn_op == CON && 3208 tn->tn_type->t_tspec == INT && 3209 tn->u.value.u.integer == 0; 3210 } 3211 3212 static void 3213 check_null_effect(const tnode_t *tn) 3214 { 3215 3216 if (hflag && 3217 !has_side_effect(tn) && 3218 !(is_void_cast(tn) && is_local_symbol(tn->u.ops.left)) && 3219 !(is_void_cast(tn) && is_int_constant_zero(tn->u.ops.left))) { 3220 /* expression has null effect */ 3221 warning(129); 3222 } 3223 } 3224 3225 /* 3226 * Check the types for specific operators and type combinations. 3227 * 3228 * At this point, the operands already conform to the type requirements of 3229 * the operator, such as being integer, floating or scalar. 3230 */ 3231 static bool 3232 typeok_op(op_t op, const function_call *call, int arg, 3233 const tnode_t *ln, const type_t *ltp, tspec_t lt, 3234 const tnode_t *rn, const type_t *rtp, tspec_t rt) 3235 { 3236 switch (op) { 3237 case ARROW: 3238 return typeok_arrow(lt); 3239 case POINT: 3240 return typeok_point(ln, ltp, lt); 3241 case INCBEF: 3242 case DECBEF: 3243 case INCAFT: 3244 case DECAFT: 3245 return typeok_incdec(op, ln, ltp); 3246 case INDIR: 3247 return typeok_indir(ltp, lt); 3248 case ADDR: 3249 return typeok_address(op, ln, ltp, lt); 3250 case PLUS: 3251 return typeok_plus(op, ltp, lt, rtp, rt); 3252 case MINUS: 3253 return typeok_minus(op, ltp, lt, rtp, rt); 3254 case SHL: 3255 typeok_shl(op, lt, rt); 3256 goto shift; 3257 case SHR: 3258 typeok_shr(op, ln, lt, rn, rt); 3259 shift: 3260 typeok_shift(ltp, lt, rn, rt); 3261 break; 3262 case LT: 3263 case LE: 3264 case GT: 3265 case GE: 3266 compare: 3267 return typeok_compare(op, ln, ltp, lt, rn, rtp, rt); 3268 case EQ: 3269 case NE: 3270 if (is_typeok_eq(ln, lt, rn, rt)) 3271 break; 3272 goto compare; 3273 case QUEST: 3274 return typeok_quest(lt, rn); 3275 case COLON: 3276 return typeok_colon(ln, ltp, lt, rn, rtp, rt); 3277 case ASSIGN: 3278 case INIT: 3279 case FARG: 3280 case RETURN: 3281 if (!check_assign_types_compatible(op, call, arg, ln, rn)) 3282 return false; 3283 goto assign; 3284 case MULASS: 3285 case DIVASS: 3286 case MODASS: 3287 goto assign; 3288 case ADDASS: 3289 case SUBASS: 3290 if ((lt == PTR && !is_integer(rt)) || rt == PTR) { 3291 warn_incompatible_types(op, ltp, lt, rtp, rt); 3292 return false; 3293 } 3294 goto assign; 3295 case SHLASS: 3296 goto assign; 3297 case SHRASS: 3298 if (pflag && !is_uinteger(lt) && 3299 !(!allow_c90 && is_uinteger(rt))) { 3300 /* bitwise '%s' on signed value possibly nonportable */ 3301 warning(117, op_name(op)); 3302 } 3303 goto assign; 3304 case ANDASS: 3305 case XORASS: 3306 case ORASS: 3307 assign: 3308 return typeok_assign(op, ln, ltp, lt); 3309 case COMMA: 3310 if (!modtab[ln->tn_op].m_has_side_effect) 3311 check_null_effect(ln); 3312 break; 3313 default: 3314 break; 3315 } 3316 return true; 3317 } 3318 3319 static void 3320 check_bad_enum_operation(op_t op, const tnode_t *ln, const tnode_t *rn) 3321 { 3322 3323 if (!eflag) 3324 return; 3325 3326 /* Allow enum in array indices. */ 3327 if (op == PLUS && 3328 ((ln->tn_type->t_is_enum && rn->tn_type->t_tspec == PTR) || 3329 (rn->tn_type->t_is_enum && ln->tn_type->t_tspec == PTR))) { 3330 return; 3331 } 3332 3333 /* dubious operation '%s' on enum */ 3334 warning(241, op_name(op)); 3335 } 3336 3337 static void 3338 check_enum_type_mismatch(op_t op, int arg, const tnode_t *ln, const tnode_t *rn) 3339 { 3340 const mod_t *mp = &modtab[op]; 3341 3342 if (ln->tn_type->u.enumer != rn->tn_type->u.enumer) { 3343 switch (op) { 3344 case INIT: 3345 /* enum type mismatch between '%s' and '%s' in ... */ 3346 warning(210, 3347 type_name(ln->tn_type), type_name(rn->tn_type)); 3348 break; 3349 case FARG: 3350 /* function expects '%s', passing '%s' for arg #%d */ 3351 warning(156, 3352 type_name(ln->tn_type), type_name(rn->tn_type), 3353 arg); 3354 break; 3355 case RETURN: 3356 /* function has return type '%s' but returns '%s' */ 3357 warning(211, 3358 type_name(ln->tn_type), type_name(rn->tn_type)); 3359 break; 3360 default: 3361 /* enum type mismatch: '%s' '%s' '%s' */ 3362 warning(130, type_name(ln->tn_type), op_name(op), 3363 type_name(rn->tn_type)); 3364 break; 3365 } 3366 } else if (Pflag && eflag && mp->m_comparison && op != EQ && op != NE) 3367 /* operator '%s' assumes that '%s' is ordered */ 3368 warning(243, op_name(op), type_name(ln->tn_type)); 3369 } 3370 3371 static void 3372 check_enum_int_mismatch(op_t op, int arg, const tnode_t *ln, const tnode_t *rn) 3373 { 3374 3375 if (!eflag) 3376 return; 3377 3378 switch (op) { 3379 case INIT: 3380 /* 3381 * Initialization with 0 is allowed. Otherwise, all implicit 3382 * initializations would need to be warned upon as well. 3383 */ 3384 if (!rn->tn_type->t_is_enum && rn->tn_op == CON && 3385 is_integer(rn->tn_type->t_tspec) && 3386 rn->u.value.u.integer == 0) { 3387 return; 3388 } 3389 /* initialization of '%s' with '%s' */ 3390 warning(277, type_name(ln->tn_type), type_name(rn->tn_type)); 3391 break; 3392 case FARG: 3393 /* combination of '%s' and '%s', arg #%d */ 3394 warning(278, 3395 type_name(ln->tn_type), type_name(rn->tn_type), arg); 3396 break; 3397 case RETURN: 3398 /* combination of '%s' and '%s' in return */ 3399 warning(279, type_name(ln->tn_type), type_name(rn->tn_type)); 3400 break; 3401 default: 3402 /* combination of '%s' and '%s', op '%s' */ 3403 warning(242, type_name(ln->tn_type), type_name(rn->tn_type), 3404 op_name(op)); 3405 break; 3406 } 3407 } 3408 3409 static void 3410 typeok_enum(op_t op, const mod_t *mp, int arg, 3411 const tnode_t *ln, const type_t *ltp, 3412 const tnode_t *rn, const type_t *rtp) 3413 { 3414 if (mp->m_bad_on_enum && 3415 (ltp->t_is_enum || (mp->m_binary && rtp->t_is_enum))) { 3416 check_bad_enum_operation(op, ln, rn); 3417 } else if (mp->m_valid_on_enum && 3418 (ltp->t_is_enum && rtp != NULL && rtp->t_is_enum)) { 3419 check_enum_type_mismatch(op, arg, ln, rn); 3420 } else if (mp->m_valid_on_enum && 3421 (ltp->t_is_enum || (rtp != NULL && rtp->t_is_enum))) { 3422 check_enum_int_mismatch(op, arg, ln, rn); 3423 } 3424 } 3425 3426 /* Perform most type checks. Return whether the types are ok. */ 3427 bool 3428 typeok(op_t op, const function_call *call, int arg, 3429 const tnode_t *ln, const tnode_t *rn) 3430 { 3431 3432 const mod_t *mp = &modtab[op]; 3433 3434 type_t *ltp = ln->tn_type; 3435 tspec_t lt = ltp->t_tspec; 3436 3437 type_t *rtp = mp->m_binary ? rn->tn_type : NULL; 3438 tspec_t rt = mp->m_binary ? rtp->t_tspec : NO_TSPEC; 3439 3440 if (Tflag && !typeok_scalar_strict_bool(op, mp, arg, ln, rn)) 3441 return false; 3442 if (!typeok_scalar(op, mp, ltp, lt, rtp, rt)) 3443 return false; 3444 3445 if (!typeok_op(op, call, arg, ln, ltp, lt, rn, rtp, rt)) 3446 return false; 3447 3448 typeok_enum(op, mp, arg, ln, ltp, rn, rtp); 3449 return true; 3450 } 3451 3452 /* In traditional C, keep unsigned and promote FLOAT to DOUBLE. */ 3453 static tspec_t 3454 promote_trad(tspec_t t) 3455 { 3456 3457 if (t == UCHAR || t == USHORT) 3458 return UINT; 3459 if (t == CHAR || t == SCHAR || t == SHORT) 3460 return INT; 3461 if (t == FLOAT) 3462 return DOUBLE; 3463 if (t == ENUM) 3464 return INT; 3465 return t; 3466 } 3467 3468 /* 3469 * C99 6.3.1.1p2 requires for types with lower rank than int that "If an int 3470 * can represent all the values of the original type, the value is converted 3471 * to an int; otherwise it is converted to an unsigned int", and that "All 3472 * other types are unchanged by the integer promotions". 3473 */ 3474 static tspec_t 3475 promote_c90(const tnode_t *tn, tspec_t t, bool farg) 3476 { 3477 if (tn->tn_type->t_bitfield) { 3478 unsigned int width = tn->tn_type->t_bit_field_width; 3479 unsigned int int_width = size_in_bits(INT); 3480 // XXX: What about _Bool bit-fields, since C99? 3481 if (width < int_width) 3482 return INT; 3483 if (width == int_width) 3484 return is_uinteger(t) ? UINT : INT; 3485 return t; 3486 } 3487 3488 if (t == CHAR || t == SCHAR) 3489 return INT; 3490 if (t == UCHAR) 3491 return size_in_bits(CHAR) < size_in_bits(INT) ? INT : UINT; 3492 if (t == SHORT) 3493 return INT; 3494 if (t == USHORT) 3495 return size_in_bits(SHORT) < size_in_bits(INT) ? INT : UINT; 3496 if (t == ENUM) 3497 return INT; 3498 if (farg && t == FLOAT) 3499 return DOUBLE; 3500 return t; 3501 } 3502 3503 /* 3504 * Performs the "integer promotions" (C99 6.3.1.1p2), which convert small 3505 * integer types to either int or unsigned int. 3506 * 3507 * If allow_c90 is unset or the operand is a function argument with no type 3508 * information (no prototype or variable # of args), converts float to double. 3509 */ 3510 tnode_t * 3511 promote(op_t op, bool farg, tnode_t *tn) 3512 { 3513 3514 const type_t *otp = tn->tn_type; 3515 tspec_t ot = otp->t_tspec; 3516 if (!is_arithmetic(ot)) 3517 return tn; 3518 3519 tspec_t nt = allow_c90 ? promote_c90(tn, ot, farg) : promote_trad(ot); 3520 if (nt == ot) 3521 return tn; 3522 3523 type_t *ntp = expr_dup_type(gettyp(nt)); 3524 ntp->t_tspec = nt; 3525 ntp->t_is_enum = otp->t_is_enum; 3526 if (ntp->t_is_enum) 3527 ntp->u.enumer = otp->u.enumer; 3528 ntp->t_bitfield = otp->t_bitfield; 3529 if (ntp->t_bitfield) { 3530 ntp->t_bit_field_width = otp->t_bit_field_width; 3531 ntp->t_bit_field_offset = otp->t_bit_field_offset; 3532 } 3533 if (ntp->t_bitfield && is_uinteger(ot) && !is_uinteger(nt)) 3534 ntp->t_bit_field_width++; 3535 return convert(op, 0, ntp, tn); 3536 } 3537 3538 static void 3539 check_lossy_floating_to_integer_conversion( 3540 op_t op, int arg, const type_t *tp, const tnode_t *tn) 3541 { 3542 long double x = tn->u.value.u.floating; 3543 integer_constraints ic = ic_any(tp); 3544 if (is_uinteger(tp->t_tspec) 3545 ? x >= ic.umin && x <= ic.umax && x == (uint64_t)x 3546 : x >= ic.smin && x <= ic.smax && x == (int64_t)x) 3547 return; 3548 if (op == FARG) 3549 /* lossy conversion of %Lg to '%s', arg #%d */ 3550 warning(380, x, type_name(tp), arg); 3551 else 3552 /* lossy conversion of %Lg to '%s' */ 3553 warning(381, x, type_name(tp)); 3554 } 3555 3556 static void 3557 convert_integer_from_floating( 3558 op_t op, int arg, const type_t *tp, const tnode_t *tn) 3559 { 3560 3561 if (op == CVT) 3562 /* cast from floating point '%s' to integer '%s' */ 3563 query_message(2, type_name(tn->tn_type), type_name(tp)); 3564 else 3565 /* implicit conversion from floating point '%s' to ... */ 3566 query_message(1, type_name(tn->tn_type), type_name(tp)); 3567 if (tn->tn_op == CON) 3568 check_lossy_floating_to_integer_conversion(op, arg, tp, tn); 3569 } 3570 3571 static bool 3572 should_warn_about_prototype_conversion(tspec_t nt, 3573 tspec_t ot, const tnode_t *ptn) 3574 { 3575 3576 if (nt == ot) 3577 return false; 3578 3579 if (nt == ENUM && ot == INT) 3580 return false; 3581 3582 if (is_floating(nt) != is_floating(ot) || 3583 portable_rank_cmp(nt, ot) != 0) { 3584 /* representation and/or width change */ 3585 if (!is_integer(ot)) 3586 return true; 3587 /* 3588 * XXX: Investigate whether this rule makes sense; see 3589 * tests/usr.bin/xlint/lint1/platform_long.c. 3590 */ 3591 return portable_rank_cmp(ot, INT) > 0; 3592 } 3593 3594 if (!hflag) 3595 return false; 3596 3597 /* 3598 * If the types differ only in sign and the argument has the same 3599 * representation in both types, print no warning. 3600 */ 3601 if (ptn->tn_op == CON && is_integer(nt) && 3602 signed_type(nt) == signed_type(ot) && 3603 !msb(ptn->u.value.u.integer, ot)) 3604 return false; 3605 3606 return true; 3607 } 3608 3609 /* 3610 * Warn if a prototype causes a type conversion that is different from what 3611 * would happen to the same argument in the absence of a prototype. This 3612 * check is intended for code that needs to stay compatible with pre-C90 C. 3613 * 3614 * Errors/warnings about invalid type combinations are already printed 3615 * in check_assign_types_compatible(). 3616 */ 3617 static void 3618 check_prototype_conversion(int arg, tspec_t nt, tspec_t ot, type_t *tp, 3619 tnode_t *tn) 3620 { 3621 3622 if (!is_arithmetic(nt) || !is_arithmetic(ot)) 3623 return; 3624 3625 /* 3626 * If the type of the formal parameter is char/short, a warning would 3627 * be useless, because functions declared the old style can't expect 3628 * char/short arguments. 3629 */ 3630 if (nt == CHAR || nt == SCHAR || nt == UCHAR || 3631 nt == SHORT || nt == USHORT) 3632 return; 3633 3634 tnode_t *ptn = promote(NOOP, true, tn); 3635 ot = ptn->tn_type->t_tspec; 3636 3637 if (should_warn_about_prototype_conversion(nt, ot, ptn)) { 3638 /* argument %d is converted from '%s' to '%s' ... */ 3639 warning(259, arg, type_name(tn->tn_type), type_name(tp)); 3640 } 3641 } 3642 3643 /* 3644 * When converting a large integer type to a small integer type, in some 3645 * cases the value of the actual expression is further restricted than the 3646 * type bounds, such as in (expr & 0xFF) or (expr % 100) or (expr >> 24). 3647 */ 3648 static bool 3649 can_represent(const type_t *tp, const tnode_t *tn) 3650 { 3651 uint64_t nmask = value_bits(width_in_bits(tp)); 3652 if (!is_uinteger(tp->t_tspec)) 3653 nmask >>= 1; 3654 3655 integer_constraints c = ic_expr(tn); 3656 if ((~c.bclr & ~nmask) == 0) 3657 return true; 3658 3659 integer_constraints tpc = ic_any(tp); 3660 if (is_uinteger(tp->t_tspec) 3661 ? tpc.umin <= c.umin && tpc.umax >= c.umax 3662 : tpc.smin <= c.smin && tpc.smax >= c.smax) 3663 return true; 3664 3665 debug_enter(); 3666 debug_step("type '%s' cannot represent:", type_name(tp)); 3667 debug_node(tn); 3668 debug_leave(); 3669 return false; 3670 } 3671 3672 static bool 3673 should_warn_about_integer_conversion(const type_t *ntp, tspec_t nt, 3674 const tnode_t *otn, tspec_t ot) 3675 { 3676 3677 // XXX: The portable_rank_cmp aims at portable mode, independent of the 3678 // current platform, while can_represent acts on the actual type sizes 3679 // from the current platform. This mix is inconsistent, but anything 3680 // else would make the exact conditions too complicated to grasp. 3681 if (aflag > 0 && portable_rank_cmp(nt, ot) < 0) { 3682 if (ot == LONG || ot == ULONG 3683 || ot == LLONG || ot == ULLONG 3684 #ifdef INT128_SIZE 3685 || ot == INT128 || ot == UINT128 3686 #endif 3687 || aflag > 1) 3688 return !can_represent(ntp, otn); 3689 } 3690 return false; 3691 } 3692 3693 static void 3694 convert_integer_from_integer(op_t op, int arg, tspec_t nt, tspec_t ot, 3695 type_t *tp, tnode_t *tn) 3696 { 3697 3698 if (tn->tn_op == CON) 3699 return; 3700 3701 if (op == CVT) 3702 return; 3703 3704 if (Pflag && pflag && aflag > 0 && 3705 portable_rank_cmp(nt, ot) > 0 && 3706 is_uinteger(nt) != is_uinteger(ot)) { 3707 if (op == FARG) 3708 /* conversion to '%s' may sign-extend ... */ 3709 warning(297, type_name(tp), arg); 3710 else 3711 /* conversion to '%s' may sign-extend ... */ 3712 warning(131, type_name(tp)); 3713 } 3714 3715 if (Pflag && portable_rank_cmp(nt, ot) > 0 && 3716 (tn->tn_op == PLUS || tn->tn_op == MINUS || tn->tn_op == MULT || 3717 tn->tn_op == SHL)) { 3718 /* suggest cast from '%s' to '%s' on op '%s' to ... */ 3719 warning(324, type_name(gettyp(ot)), type_name(tp), 3720 op_name(tn->tn_op)); 3721 } 3722 3723 if (should_warn_about_integer_conversion(tp, nt, tn, ot)) { 3724 if (op == FARG) { 3725 /* conversion from '%s' to '%s' may lose ... */ 3726 warning(298, 3727 type_name(tn->tn_type), type_name(tp), arg); 3728 } else { 3729 /* conversion from '%s' to '%s' may lose accuracy */ 3730 warning(132, 3731 type_name(tn->tn_type), type_name(tp)); 3732 } 3733 } 3734 3735 if (is_uinteger(nt) != is_uinteger(ot)) 3736 /* implicit conversion changes sign from '%s' to '%s' */ 3737 query_message(3, type_name(tn->tn_type), type_name(tp)); 3738 } 3739 3740 static void 3741 convert_integer_from_pointer(op_t op, tspec_t nt, type_t *tp, tnode_t *tn) 3742 { 3743 3744 if (tn->tn_op == CON) 3745 return; 3746 if (op != CVT) 3747 return; /* We already got an error. */ 3748 if (portable_rank_cmp(nt, PTR) >= 0) 3749 return; 3750 3751 if (pflag && size_in_bits(nt) >= size_in_bits(PTR)) { 3752 /* conversion of pointer to '%s' may lose bits */ 3753 warning(134, type_name(tp)); 3754 } else { 3755 /* conversion of pointer to '%s' loses bits */ 3756 warning(133, type_name(tp)); 3757 } 3758 } 3759 3760 static bool 3761 struct_starts_with(const type_t *struct_tp, const type_t *member_tp) 3762 { 3763 3764 return struct_tp->u.sou->sou_first_member != NULL && 3765 types_compatible(struct_tp->u.sou->sou_first_member->s_type, 3766 member_tp, true, false, NULL); 3767 } 3768 3769 static bool 3770 is_byte_array(const type_t *tp) 3771 { 3772 3773 return tp->t_tspec == ARRAY && 3774 (tp->t_subt->t_tspec == CHAR || tp->t_subt->t_tspec == UCHAR); 3775 } 3776 3777 static bool 3778 union_contains(const type_t *utp, const type_t *mtp) 3779 { 3780 for (const sym_t *mem = utp->u.sou->sou_first_member; 3781 mem != NULL; mem = mem->s_next) { 3782 if (types_compatible(mem->s_type, mtp, true, false, NULL)) 3783 return true; 3784 } 3785 return false; 3786 } 3787 3788 static bool 3789 should_warn_about_pointer_cast(const type_t *nstp, tspec_t nst, 3790 const type_t *ostp, tspec_t ost) 3791 { 3792 3793 while (nst == ARRAY) 3794 nstp = nstp->t_subt, nst = nstp->t_tspec; 3795 while (ost == ARRAY) 3796 ostp = ostp->t_subt, ost = ostp->t_tspec; 3797 3798 if (nst == STRUCT && ost == STRUCT && 3799 (struct_starts_with(nstp, ostp) || 3800 struct_starts_with(ostp, nstp))) 3801 return false; 3802 3803 if (is_incomplete(nstp) || is_incomplete(ostp)) 3804 return false; 3805 3806 if (nst == CHAR || nst == UCHAR) 3807 return false; /* for the sake of traditional C code */ 3808 if (ost == CHAR || ost == UCHAR) 3809 return false; /* for the sake of traditional C code */ 3810 3811 /* Allow cast between pointers to sockaddr variants. */ 3812 if (nst == STRUCT && ost == STRUCT) { 3813 const sym_t *nmem = nstp->u.sou->sou_first_member; 3814 const sym_t *omem = ostp->u.sou->sou_first_member; 3815 while (nmem != NULL && omem != NULL && 3816 types_compatible(nmem->s_type, omem->s_type, 3817 true, false, NULL)) 3818 nmem = nmem->s_next, omem = omem->s_next; 3819 if (nmem != NULL && is_byte_array(nmem->s_type)) 3820 return false; 3821 if (omem != NULL && is_byte_array(omem->s_type)) 3822 return false; 3823 if (nmem == NULL && omem == NULL) 3824 return false; 3825 } 3826 3827 if (nst == UNION || ost == UNION) { 3828 const type_t *union_tp = nst == UNION ? nstp : ostp; 3829 const type_t *other_tp = nst == UNION ? ostp : nstp; 3830 if (union_contains(union_tp, other_tp)) 3831 return false; 3832 } 3833 3834 if (is_struct_or_union(nst) && is_struct_or_union(ost)) 3835 return nstp->u.sou != ostp->u.sou; 3836 3837 enum rank_kind rk1 = type_properties(nst)->tt_rank_kind; 3838 enum rank_kind rk2 = type_properties(ost)->tt_rank_kind; 3839 if (rk1 != rk2 || rk1 == RK_NONE) 3840 return true; 3841 3842 return portable_rank_cmp(nst, ost) != 0; 3843 } 3844 3845 static void 3846 convert_pointer_from_pointer(type_t *ntp, tnode_t *tn) 3847 { 3848 const type_t *nstp = ntp->t_subt; 3849 const type_t *otp = tn->tn_type; 3850 const type_t *ostp = otp->t_subt; 3851 tspec_t nst = nstp->t_tspec; 3852 tspec_t ost = ostp->t_tspec; 3853 3854 if (nst == VOID || ost == VOID) { 3855 /* TODO: C99 behaves like C90 here. */ 3856 if (!allow_trad && !allow_c99 && (nst == FUNC || ost == FUNC)) { 3857 const char *nts, *ots; 3858 /* null pointers are already handled in convert() */ 3859 *(nst == FUNC ? &nts : &ots) = "function pointer"; 3860 *(nst == VOID ? &nts : &ots) = "'void *'"; 3861 /* conversion of %s to %s requires a cast */ 3862 warning(303, ots, nts); 3863 } 3864 return; 3865 } 3866 if (nst == FUNC && ost == FUNC) 3867 return; 3868 if (nst == FUNC || ost == FUNC) { 3869 /* converting '%s' to '%s' is questionable */ 3870 warning(229, type_name(otp), type_name(ntp)); 3871 return; 3872 } 3873 3874 if (hflag && alignment(nstp) > alignment(ostp) && 3875 !is_incomplete(ostp) && alignment(ostp) > 1 && 3876 !(nst == UNION && union_contains(nstp, ostp))) { 3877 /* converting '%s' to '%s' increases alignment ... */ 3878 warning(135, type_name(otp), type_name(ntp), 3879 alignment(ostp), alignment(nstp)); 3880 } 3881 3882 if (cflag && should_warn_about_pointer_cast(nstp, nst, ostp, ost)) { 3883 /* pointer cast from '%s' to unrelated '%s' */ 3884 warning(247, type_name(ostp), type_name(nstp)); 3885 } 3886 } 3887 3888 /* 3889 * Insert a conversion operator, which converts the type of the node 3890 * to another given type. 3891 * 3892 * Possible values for 'op': 3893 * CVT a cast-expression 3894 * binary integer promotion for one of the operands, or a usual 3895 * arithmetic conversion 3896 * binary plain or compound assignments to bit-fields 3897 * FARG 'arg' is the number of the parameter (used for warnings) 3898 * NOOP several other implicit conversions 3899 * ... 3900 */ 3901 tnode_t * 3902 convert(op_t op, int arg, type_t *tp, tnode_t *tn) 3903 { 3904 tspec_t nt = tp->t_tspec; 3905 tspec_t ot = tn->tn_type->t_tspec; 3906 3907 if (allow_trad && allow_c90 && op == FARG) 3908 check_prototype_conversion(arg, nt, ot, tp, tn); 3909 3910 if (nt == BOOL) { 3911 /* No further checks. */ 3912 3913 } else if (is_integer(nt)) { 3914 if (ot == BOOL) { 3915 /* No further checks. */ 3916 } else if (is_integer(ot)) 3917 convert_integer_from_integer(op, arg, nt, ot, tp, tn); 3918 else if (is_floating(ot)) 3919 convert_integer_from_floating(op, arg, tp, tn); 3920 else if (ot == PTR) 3921 convert_integer_from_pointer(op, nt, tp, tn); 3922 3923 } else if (is_floating(nt)) { 3924 if (is_integer(ot) && op != CVT) { 3925 /* implicit conversion from integer '%s' to ... */ 3926 query_message(19, 3927 type_name(tn->tn_type), type_name(tp)); 3928 } 3929 3930 } else if (nt == PTR) { 3931 if (is_null_pointer(tn)) { 3932 /* a null pointer may be assigned to any pointer. */ 3933 } else if (ot == PTR && op == CVT) 3934 convert_pointer_from_pointer(tp, tn); 3935 } 3936 3937 tnode_t *ntn = expr_alloc_tnode(); 3938 ntn->tn_op = CVT; 3939 ntn->tn_type = tp; 3940 ntn->tn_cast = op == CVT; 3941 ntn->tn_sys |= tn->tn_sys; 3942 ntn->u.ops.right = NULL; 3943 if (tn->tn_op != CON || nt == VOID) { 3944 ntn->u.ops.left = tn; 3945 } else { 3946 ntn->tn_op = CON; 3947 convert_constant(op, arg, ntn->tn_type, &ntn->u.value, 3948 &tn->u.value); 3949 } 3950 3951 return ntn; 3952 } 3953 3954 static void 3955 convert_constant_from_floating(op_t op, int arg, const type_t *ntp, 3956 tspec_t nt, val_t *nv, val_t *ov) 3957 { 3958 long double max = 0.0, min = 0.0; 3959 3960 switch (nt) { 3961 case CHAR: 3962 max = TARG_CHAR_MAX; min = TARG_CHAR_MIN; break; 3963 case UCHAR: 3964 max = TARG_UCHAR_MAX; min = 0; break; 3965 case SCHAR: 3966 max = TARG_SCHAR_MAX; min = TARG_SCHAR_MIN; break; 3967 case SHORT: 3968 max = TARG_SHRT_MAX; min = TARG_SHRT_MIN; break; 3969 case USHORT: 3970 max = TARG_USHRT_MAX; min = 0; break; 3971 case ENUM: 3972 case INT: 3973 max = TARG_INT_MAX; min = TARG_INT_MIN; break; 3974 case UINT: 3975 max = TARG_UINT_MAX; min = 0; break; 3976 case LONG: 3977 max = TARG_LONG_MAX; min = TARG_LONG_MIN; break; 3978 case ULONG: 3979 max = TARG_ULONG_MAX; min = 0; break; 3980 case LLONG: 3981 max = LLONG_MAX; min = LLONG_MIN; break; 3982 case ULLONG: 3983 max = ULLONG_MAX; min = 0; break; 3984 case FLOAT: 3985 case FCOMPLEX: 3986 max = FLT_MAX; min = -FLT_MAX; break; 3987 case DOUBLE: 3988 case DCOMPLEX: 3989 max = DBL_MAX; min = -DBL_MAX; break; 3990 case LDOUBLE: 3991 case LCOMPLEX: 3992 /* LINTED 248; see floating_error_value. */ 3993 max = LDBL_MAX; min = -max; break; 3994 default: 3995 lint_assert(false); 3996 } 3997 if (ov->u.floating > max || ov->u.floating < min) { 3998 lint_assert(nt != LDOUBLE); 3999 const char *ot_name = type_name(gettyp(ov->v_tspec)); 4000 const char *nt_name = type_name(ntp); 4001 if (is_integer(nt)) 4002 goto after_warning; 4003 if (op == FARG) 4004 /* conversion of '%s' to '%s' is out of range, ... */ 4005 warning(295, ot_name, nt_name, arg); 4006 else 4007 /* conversion of '%s' to '%s' is out of range */ 4008 warning(119, ot_name, nt_name); 4009 after_warning: 4010 ov->u.floating = ov->u.floating > 0 ? max : min; 4011 } 4012 4013 if (nt == FLOAT || nt == FCOMPLEX) 4014 nv->u.floating = (float)ov->u.floating; 4015 else if (nt == DOUBLE || nt == DCOMPLEX) 4016 nv->u.floating = (double)ov->u.floating; 4017 else if (nt == LDOUBLE || nt == LCOMPLEX) 4018 nv->u.floating = ov->u.floating; 4019 else 4020 nv->u.integer = (int64_t)ov->u.floating; 4021 } 4022 4023 static bool 4024 convert_constant_to_floating(tspec_t nt, val_t *nv, 4025 tspec_t ot, const val_t *v) 4026 { 4027 if (nt == FLOAT) { 4028 nv->u.floating = (ot == PTR || is_uinteger(ot)) ? 4029 (float)(uint64_t)v->u.integer : (float)v->u.integer; 4030 } else if (nt == DOUBLE) { 4031 nv->u.floating = (ot == PTR || is_uinteger(ot)) ? 4032 (double)(uint64_t)v->u.integer : (double)v->u.integer; 4033 } else if (nt == LDOUBLE) { 4034 nv->u.floating = (ot == PTR || is_uinteger(ot)) 4035 ? (long double)(uint64_t)v->u.integer 4036 : (long double)v->u.integer; 4037 } else 4038 return false; 4039 return true; 4040 } 4041 4042 static void 4043 warn_constant_truncated(op_t op, const val_t *v) 4044 { 4045 char buf[256]; 4046 bool is_unsigned = is_uinteger(v->v_tspec); 4047 int64_t val = v->u.integer; 4048 unsigned long long abs_val = is_unsigned || val >= 0 4049 ? (unsigned long long)val 4050 : -(unsigned long long)val; 4051 const char *sign = is_unsigned || val >= 0 ? "" : "-"; 4052 snprintf(buf, sizeof(buf), "%s%#llx", sign, abs_val); 4053 /* constant %s truncated by conversion, op '%s' */ 4054 warning(306, buf, op_name(op)); 4055 } 4056 4057 static void 4058 convert_constant_check_range_bitor(size_t nsz, size_t osz, const val_t *v, 4059 uint64_t xmask, op_t op) 4060 { 4061 if (nsz < osz && (v->u.integer & xmask) != 0) 4062 warn_constant_truncated(op, v); 4063 } 4064 4065 static void 4066 convert_constant_check_range_bitand(size_t nsz, size_t osz, 4067 uint64_t xmask, const val_t *nv, 4068 tspec_t ot, const val_t *v, 4069 const type_t *tp, op_t op) 4070 { 4071 if (nsz > osz && 4072 (nv->u.integer & bit((unsigned int)(osz - 1))) != 0 && 4073 (nv->u.integer & xmask) != xmask) { 4074 /* extra bits set to 0 in conversion of '%s' to '%s', ... */ 4075 warning(309, type_name(gettyp(ot)), 4076 type_name(tp), op_name(op)); 4077 } else if (nsz < osz && 4078 (v->u.integer & xmask) != xmask && 4079 (v->u.integer & xmask) != 0) 4080 warn_constant_truncated(op, v); 4081 } 4082 4083 static void 4084 convert_constant_check_range_signed(op_t op, int arg, 4085 const type_t *ntp, int64_t ov) 4086 { 4087 if (op == ASSIGN) 4088 /* assignment of negative constant %lld to unsigned ... */ 4089 warning(164, (long long)ov, type_name(ntp)); 4090 else if (op == INIT) 4091 /* initialization of unsigned type '%s' with negative ... */ 4092 warning(221, type_name(ntp), (long long)ov); 4093 else if (op == FARG) 4094 /* conversion of negative constant %lld to unsigned ... */ 4095 warning(296, (long long)ov, type_name(ntp), arg); 4096 else if (modtab[op].m_comparison) { 4097 /* handled by check_integer_comparison() */ 4098 } else 4099 /* conversion of negative constant %lld to unsigned ... */ 4100 warning(222, (long long)ov, type_name(ntp)); 4101 } 4102 4103 /* 4104 * Loss of significant bit(s). All truncated bits of unsigned types or all 4105 * truncated bits plus the msb of the target for signed types are considered 4106 * to be significant bits. Loss of significant bits means that at least one 4107 * of the bits was set in an unsigned type or that at least one but not all 4108 * of the bits was set in a signed type. Loss of significant bits means that 4109 * it is not possible, also not with necessary casts, to convert back to the 4110 * original type. An example for a necessary cast is: 4111 * char c; int i; c = 128; 4112 * i = c; ** yields -128 ** 4113 * i = (unsigned char)c; ** yields 128 ** 4114 */ 4115 static void 4116 warn_constant_check_range_truncated(op_t op, int arg, const type_t *tp, 4117 tspec_t ot) 4118 { 4119 if (op == ASSIGN && tp->t_bitfield) 4120 /* precision lost in bit-field assignment */ 4121 warning(166); 4122 else if (op == ASSIGN) 4123 /* constant truncated by assignment */ 4124 warning(165); 4125 else if (op == INIT && tp->t_bitfield) 4126 /* bit-field initializer does not fit */ 4127 warning(180); 4128 else if (op == INIT) 4129 /* initializer does not fit */ 4130 warning(178); 4131 else if (op == CASE) 4132 /* case label is converted from '%s' to '%s' */ 4133 warning(196, tspec_name(ot), type_name(tp)); 4134 else if (op == FARG) 4135 /* conversion of '%s' to '%s' is out of range, arg #%d */ 4136 warning(295, type_name(gettyp(ot)), type_name(tp), arg); 4137 else 4138 /* conversion of '%s' to '%s' is out of range */ 4139 warning(119, type_name(gettyp(ot)), type_name(tp)); 4140 } 4141 4142 static void 4143 warn_constant_check_range_loss(op_t op, int arg, const type_t *tp, 4144 tspec_t ot) 4145 { 4146 if (op == ASSIGN && tp->t_bitfield) 4147 /* precision lost in bit-field assignment */ 4148 warning(166); 4149 else if (op == INIT && tp->t_bitfield) 4150 /* bit-field initializer out of range */ 4151 warning(11); 4152 else if (op == CASE) 4153 /* case label is converted from '%s' to '%s' */ 4154 warning(196, tspec_name(ot), type_name(tp)); 4155 else if (op == FARG) 4156 /* conversion of '%s' to '%s' is out of range, arg #%d */ 4157 warning(295, type_name(gettyp(ot)), type_name(tp), arg); 4158 else 4159 /* conversion of '%s' to '%s' is out of range */ 4160 warning(119, type_name(gettyp(ot)), type_name(tp)); 4161 } 4162 4163 static void 4164 convert_constant_check_range(tspec_t ot, const type_t *tp, tspec_t nt, 4165 op_t op, int arg, const val_t *v, val_t *nv) 4166 { 4167 unsigned int obitsz, nbitsz; 4168 uint64_t xmask, xmsk1; 4169 4170 obitsz = size_in_bits(ot); 4171 nbitsz = tp->t_bitfield ? tp->t_bit_field_width : size_in_bits(nt); 4172 xmask = value_bits(nbitsz) ^ value_bits(obitsz); 4173 xmsk1 = value_bits(nbitsz) ^ value_bits(obitsz - 1); 4174 if (op == ORASS || op == BITOR || op == BITXOR) { 4175 convert_constant_check_range_bitor( 4176 nbitsz, obitsz, v, xmask, op); 4177 } else if (op == ANDASS || op == BITAND) { 4178 convert_constant_check_range_bitand( 4179 nbitsz, obitsz, xmask, nv, ot, v, tp, op); 4180 } else if (nt != PTR && is_uinteger(nt) && 4181 ot != PTR && !is_uinteger(ot) && 4182 v->u.integer < 0) 4183 convert_constant_check_range_signed(op, arg, 4184 tp, v->u.integer); 4185 else if (nv->u.integer != v->u.integer && nbitsz <= obitsz && 4186 (v->u.integer & xmask) != 0 && 4187 (is_uinteger(ot) || (v->u.integer & xmsk1) != xmsk1)) 4188 warn_constant_check_range_truncated(op, arg, tp, ot); 4189 else if (nv->u.integer != v->u.integer) 4190 warn_constant_check_range_loss(op, arg, tp, ot); 4191 } 4192 4193 /* Converts a typed constant to a constant of another type. */ 4194 void 4195 convert_constant(op_t op, int arg, const type_t *ntp, val_t *nv, val_t *ov) 4196 { 4197 /* 4198 * TODO: make 'ov' const; the name of this function does not suggest 4199 * that it modifies 'ov'. 4200 */ 4201 tspec_t ot = ov->v_tspec; 4202 tspec_t nt = nv->v_tspec = ntp->t_tspec; 4203 bool range_check = false; 4204 4205 if (nt == BOOL) { /* C99 6.3.1.2 */ 4206 nv->v_unsigned_since_c90 = false; 4207 nv->u.integer = is_nonzero_val(ov) ? 1 : 0; 4208 return; 4209 } 4210 4211 if (ot == FLOAT || ot == DOUBLE || ot == LDOUBLE) 4212 convert_constant_from_floating(op, arg, ntp, nt, nv, ov); 4213 else if (!convert_constant_to_floating(nt, nv, ot, ov)) { 4214 range_check = true; /* Check for lost precision. */ 4215 nv->u.integer = ov->u.integer; 4216 } 4217 4218 if (allow_trad && allow_c90 && ov->v_unsigned_since_c90 && 4219 (is_floating(nt) || ( 4220 (is_integer(nt) && !is_uinteger(nt) && 4221 portable_rank_cmp(nt, ot) > 0)))) { 4222 /* C90 treats constant as unsigned */ 4223 warning(157); 4224 ov->v_unsigned_since_c90 = false; 4225 } 4226 4227 if (is_integer(nt)) { 4228 unsigned int size = ntp->t_bitfield 4229 ? ntp->t_bit_field_width : size_in_bits(nt); 4230 nv->u.integer = convert_integer(nv->u.integer, nt, size); 4231 } 4232 4233 if (range_check && op != CVT) 4234 convert_constant_check_range(ot, ntp, nt, op, arg, ov, nv); 4235 } 4236 4237 tnode_t * 4238 build_sizeof(const type_t *tp) 4239 { 4240 unsigned int size_in_bytes = type_size_in_bits(tp) / CHAR_SIZE; 4241 tnode_t *tn = build_integer_constant(SIZEOF_TSPEC, size_in_bytes); 4242 tn->tn_system_dependent = true; 4243 debug_step("build_sizeof '%s' = %u", type_name(tp), size_in_bytes); 4244 return tn; 4245 } 4246 4247 tnode_t * 4248 build_offsetof(const type_t *tp, designation dn) 4249 { 4250 unsigned int offset_in_bits = 0; 4251 4252 if (!is_struct_or_union(tp->t_tspec)) { 4253 /* unacceptable operand of '%s' */ 4254 error(111, "offsetof"); 4255 goto proceed; 4256 } 4257 for (size_t i = 0; i < dn.dn_len; i++) { 4258 const designator *dr = dn.dn_items + i; 4259 if (dr->dr_kind == DK_SUBSCRIPT) { 4260 if (tp->t_tspec != ARRAY) 4261 goto proceed; /* silent error */ 4262 tp = tp->t_subt; 4263 offset_in_bits += (unsigned)dr->dr_subscript 4264 * type_size_in_bits(tp); 4265 } else { 4266 if (!is_struct_or_union(tp->t_tspec)) 4267 goto proceed; /* silent error */ 4268 const char *name = dr->dr_member->s_name; 4269 sym_t *mem = find_member(tp->u.sou, name); 4270 if (mem == NULL) { 4271 /* type '%s' does not have member '%s' */ 4272 error(101, name, type_name(tp)); 4273 goto proceed; 4274 } 4275 tp = mem->s_type; 4276 offset_in_bits += mem->u.s_member.sm_offset_in_bits; 4277 } 4278 } 4279 free(dn.dn_items); 4280 4281 proceed:; 4282 unsigned int offset_in_bytes = offset_in_bits / CHAR_SIZE; 4283 tnode_t *tn = build_integer_constant(SIZEOF_TSPEC, offset_in_bytes); 4284 tn->tn_system_dependent = true; 4285 return tn; 4286 } 4287 4288 unsigned int 4289 type_size_in_bits(const type_t *tp) 4290 { 4291 4292 unsigned int elem = 1; 4293 bool flex = false; 4294 lint_assert(tp != NULL); 4295 while (tp->t_tspec == ARRAY) { 4296 flex = true; /* allow c99 flex arrays [] [0] */ 4297 elem *= tp->u.dimension; 4298 tp = tp->t_subt; 4299 } 4300 if (elem == 0 && !flex) { 4301 /* cannot take size/alignment of incomplete type */ 4302 error(143); 4303 elem = 1; 4304 } 4305 4306 unsigned int elsz; 4307 switch (tp->t_tspec) { 4308 case VOID: 4309 /* cannot take size/alignment of void */ 4310 error(146); 4311 elsz = 1; 4312 break; 4313 case FUNC: 4314 /* cannot take size/alignment of function type '%s' */ 4315 error(144, type_name(tp)); 4316 elsz = 1; 4317 break; 4318 case STRUCT: 4319 case UNION: 4320 if (is_incomplete(tp)) { 4321 /* cannot take size/alignment of incomplete type */ 4322 error(143); 4323 elsz = 1; 4324 } else 4325 elsz = tp->u.sou->sou_size_in_bits; 4326 break; 4327 case ENUM: 4328 if (is_incomplete(tp)) { 4329 /* cannot take size/alignment of incomplete type */ 4330 warning(143); 4331 } 4332 /* FALLTHROUGH */ 4333 default: 4334 if (tp->t_bitfield) 4335 /* cannot take size/alignment of bit-field */ 4336 error(145); 4337 elsz = size_in_bits(tp->t_tspec); 4338 lint_assert(elsz > 0); 4339 break; 4340 } 4341 4342 return elem * elsz; 4343 } 4344 4345 /* C11 6.5.3.4, GCC */ 4346 tnode_t * 4347 build_alignof(const type_t *tp) 4348 { 4349 if (tp->t_tspec == FUNC) { 4350 /* cannot take size/alignment of function type '%s' */ 4351 error(144, type_name(tp)); 4352 return NULL; 4353 } 4354 if (tp->t_tspec == VOID) { 4355 /* cannot take size/alignment of void */ 4356 error(146); 4357 return NULL; 4358 } 4359 if (is_incomplete(tp)) { 4360 /* cannot take size/alignment of incomplete type */ 4361 error(143); 4362 return NULL; 4363 } 4364 if (tp->t_bitfield) { 4365 /* cannot take size/alignment of bit-field */ 4366 error(145); 4367 return NULL; 4368 } 4369 return build_integer_constant(SIZEOF_TSPEC, (int64_t)alignment(tp)); 4370 } 4371 4372 static tnode_t * 4373 cast_to_union(tnode_t *otn, bool sys, type_t *ntp) 4374 { 4375 4376 if (!allow_gcc) { 4377 /* union cast is a GCC extension */ 4378 error(328); 4379 return NULL; 4380 } 4381 4382 for (const sym_t *m = ntp->u.sou->sou_first_member; 4383 m != NULL; m = m->s_next) { 4384 if (types_compatible(m->s_type, otn->tn_type, 4385 false, false, NULL)) { 4386 tnode_t *ntn = build_op(CVT, sys, ntp, otn, NULL); 4387 ntn->tn_cast = true; 4388 return ntn; 4389 } 4390 } 4391 4392 /* type '%s' is not a member of '%s' */ 4393 error(329, type_name(otn->tn_type), type_name(ntp)); 4394 return NULL; 4395 } 4396 4397 // In GCC mode, allow 'nullptr + offset' as a constant expression. 4398 static tnode_t * 4399 null_pointer_offset(tnode_t *tn) 4400 { 4401 uint64_t off = 0; 4402 const tnode_t *n = tn; 4403 while ((n->tn_op == PLUS || n->tn_op == MINUS) 4404 && is_integer(n->u.ops.right->tn_type->t_tspec)) { 4405 off += (uint64_t)n->u.ops.right->u.value.u.integer; 4406 n = n->u.ops.left; 4407 } 4408 if (n->tn_type->t_tspec == PTR 4409 && n->tn_op == ADDR 4410 && n->u.ops.left->tn_op == INDIR 4411 && n->u.ops.left->u.ops.left->tn_op == CON 4412 && n->u.ops.left->u.ops.left->tn_type->t_tspec == PTR) { 4413 off += (uint64_t)n->u.ops.left->u.ops.left->u.value.u.integer; 4414 return build_integer_constant(SIZEOF_TSPEC, (int64_t)off); 4415 } 4416 return tn; 4417 } 4418 4419 tnode_t * 4420 cast(tnode_t *tn, bool sys, type_t *tp) 4421 { 4422 4423 if (tn == NULL) 4424 return NULL; 4425 4426 tn = cconv(tn); 4427 4428 lint_assert(tp != NULL); 4429 tspec_t nt = tp->t_tspec; 4430 tspec_t ot = tn->tn_type->t_tspec; 4431 4432 if (nt == VOID) { 4433 /* 4434 * C90 6.3.4, C99 6.5.4p2 and C11 6.5.4p2 allow any type to be 4435 * cast to void. The only other allowed casts are from a 4436 * scalar type to a scalar type. 4437 */ 4438 } else if (nt == UNION) 4439 return cast_to_union(tn, sys, tp); 4440 else if (nt == STRUCT || nt == ARRAY || nt == FUNC) { 4441 /* Casting to a struct is an undocumented GCC extension. */ 4442 if (!(allow_gcc && nt == STRUCT)) 4443 goto invalid_cast; 4444 } else if (is_struct_or_union(ot)) 4445 goto invalid_cast; 4446 else if (ot == VOID) { 4447 /* improper cast of void expression */ 4448 error(148); 4449 return NULL; 4450 } else if (is_integer(nt) && is_scalar(ot)) { 4451 tn = null_pointer_offset(tn); 4452 } else if (is_floating(nt) && is_arithmetic(ot)) { 4453 /* ok */ 4454 } else if (nt == PTR && is_integer(ot)) { 4455 /* ok */ 4456 } else if (nt == PTR && ot == PTR) { 4457 if (!tp->t_subt->t_const && tn->tn_type->t_subt->t_const) { 4458 if (hflag) 4459 /* cast discards 'const' from type '%s' */ 4460 warning(275, type_name(tn->tn_type)); 4461 } 4462 } else 4463 goto invalid_cast; 4464 4465 if (any_query_enabled 4466 && types_compatible(tp, tn->tn_type, false, false, NULL)) 4467 /* no-op cast from '%s' to '%s' */ 4468 query_message(6, type_name(tn->tn_type), type_name(tp)); 4469 4470 tn = convert(CVT, 0, tp, tn); 4471 tn->tn_cast = true; 4472 tn->tn_sys = sys; 4473 4474 return tn; 4475 4476 invalid_cast: 4477 /* invalid cast from '%s' to '%s' */ 4478 error(147, type_name(tn->tn_type), type_name(tp)); 4479 return NULL; 4480 } 4481 4482 void 4483 add_function_argument(function_call *call, tnode_t *arg) 4484 { 4485 /* 4486 * If there was a serious error in the expression for the argument, 4487 * create a dummy argument so the positions of the remaining arguments 4488 * will not change. 4489 */ 4490 if (arg == NULL) 4491 arg = build_integer_constant(INT, 0); 4492 4493 if (call->args_len >= call->args_cap) { 4494 call->args_cap += 8; 4495 tnode_t **new_args = expr_zero_alloc( 4496 call->args_cap * sizeof(*call->args), "tnode*[]"); 4497 if (call->args_len > 0) 4498 memcpy(new_args, call->args, 4499 call->args_len * sizeof(*call->args)); 4500 call->args = new_args; 4501 } 4502 call->args[call->args_len++] = arg; 4503 } 4504 4505 /* 4506 * Compare the type of an argument with the corresponding type of a 4507 * prototype parameter. If it is a valid combination, but both types 4508 * are not the same, insert a conversion to convert the argument into 4509 * the type of the parameter. 4510 */ 4511 static tnode_t * 4512 check_prototype_argument(const function_call *call, int arg, 4513 type_t *tp, tnode_t *tn) 4514 { 4515 tnode_t *ln = xcalloc(1, sizeof(*ln)); 4516 ln->tn_type = expr_unqualified_type(tp); 4517 ln->tn_lvalue = true; 4518 if (typeok(FARG, call, arg, ln, tn)) { 4519 bool dowarn; 4520 if (!types_compatible(tp, tn->tn_type, 4521 true, false, (dowarn = false, &dowarn)) || dowarn) 4522 tn = convert(FARG, arg, tp, tn); 4523 } 4524 free(ln); 4525 return tn; 4526 } 4527 4528 /* 4529 * Check types of all function arguments and insert conversions, 4530 * if necessary. 4531 */ 4532 static void 4533 check_function_arguments(const function_call *call) 4534 { 4535 type_t *ftp = call->func->tn_type->t_subt; 4536 4537 /* get # of parameters in the prototype */ 4538 int npar = 0; 4539 for (const sym_t *p = ftp->u.params; p != NULL; p = p->s_next) 4540 npar++; 4541 4542 int narg = (int)call->args_len; 4543 4544 const sym_t *param = ftp->u.params; 4545 if (ftp->t_proto && npar != narg && !(ftp->t_vararg && npar < narg)) { 4546 /* argument mismatch: %d %s passed, %d expected */ 4547 error(150, narg, narg != 1 ? "arguments" : "argument", npar); 4548 param = NULL; 4549 } 4550 4551 for (int i = 0; i < narg; i++) { 4552 tnode_t *arg = call->args[i]; 4553 4554 /* some things which are always not allowed */ 4555 tspec_t at = arg->tn_type->t_tspec; 4556 if (at == VOID) { 4557 /* void expressions may not be arguments, arg #%d */ 4558 error(151, i + 1); 4559 return; 4560 } 4561 if (is_struct_or_union(at) && is_incomplete(arg->tn_type)) { 4562 /* argument cannot have unknown size, arg #%d */ 4563 error(152, i + 1); 4564 return; 4565 } 4566 if (is_integer(at) && 4567 arg->tn_type->t_is_enum && 4568 is_incomplete(arg->tn_type)) { 4569 /* argument cannot have unknown size, arg #%d */ 4570 warning(152, i + 1); 4571 } 4572 4573 arg = cconv(arg); 4574 call->args[i] = arg; 4575 4576 arg = param != NULL 4577 ? check_prototype_argument(call, i + 1, param->s_type, arg) 4578 : promote(NOOP, true, arg); 4579 call->args[i] = arg; 4580 4581 if (param != NULL) 4582 param = param->s_next; 4583 } 4584 } 4585 4586 tnode_t * 4587 build_function_call(tnode_t *func, bool sys, function_call *call) 4588 { 4589 4590 if (func == NULL) 4591 return NULL; 4592 4593 call->func = func; 4594 check_ctype_function_call(call); 4595 4596 func = cconv(func); 4597 call->func = func; 4598 4599 if (func->tn_type->t_tspec != PTR || 4600 func->tn_type->t_subt->t_tspec != FUNC) { 4601 /* cannot call '%s', must be a function */ 4602 error(149, type_name(func->tn_type)); 4603 return NULL; 4604 } 4605 4606 check_function_arguments(call); 4607 4608 tnode_t *ntn = expr_alloc_tnode(); 4609 ntn->tn_op = CALL; 4610 ntn->tn_type = func->tn_type->t_subt->t_subt; 4611 ntn->tn_sys = sys; 4612 ntn->u.call = call; 4613 return ntn; 4614 } 4615 4616 /* 4617 * Return the value of an integral constant expression. 4618 * If the expression is not constant or its type is not an integer 4619 * type, an error message is printed. 4620 */ 4621 val_t * 4622 integer_constant(tnode_t *tn, bool required) 4623 { 4624 4625 if (tn != NULL) 4626 tn = cconv(tn); 4627 if (tn != NULL) 4628 tn = promote(NOOP, false, tn); 4629 4630 val_t *v = xcalloc(1, sizeof(*v)); 4631 4632 if (tn == NULL) { 4633 lint_assert(seen_error); 4634 debug_step("constant node is null; returning 1 instead"); 4635 v->v_tspec = INT; 4636 v->u.integer = 1; 4637 return v; 4638 } 4639 4640 v->v_tspec = tn->tn_type->t_tspec; 4641 4642 if (tn->tn_op == CON) { 4643 lint_assert(tn->tn_type->t_tspec == tn->u.value.v_tspec); 4644 if (is_integer(tn->u.value.v_tspec)) { 4645 v->v_unsigned_since_c90 = 4646 tn->u.value.v_unsigned_since_c90; 4647 v->u.integer = tn->u.value.u.integer; 4648 return v; 4649 } 4650 v->u.integer = (int64_t)tn->u.value.u.floating; 4651 } else 4652 v->u.integer = 1; 4653 4654 if (required) 4655 /* integral constant expression expected */ 4656 error(55); 4657 else 4658 /* variable array dimension is a C99/GCC extension */ 4659 c99ism(318); 4660 4661 if (!is_integer(v->v_tspec)) 4662 v->v_tspec = INT; 4663 4664 return v; 4665 } 4666 4667 /* 4668 * Perform some tests on expressions which can't be done in build_binary() 4669 * and functions called by build_binary(). These tests must be done here 4670 * because we need some information about the context in which the operations 4671 * are performed. 4672 * After all tests are performed and dofreeblk is true, expr() frees the 4673 * memory which is used for the expression. 4674 */ 4675 void 4676 expr(tnode_t *tn, bool vctx, bool cond, bool dofreeblk, bool is_do_while, 4677 const char *stmt_kind) 4678 { 4679 4680 if (tn == NULL) { /* in case of errors */ 4681 expr_free_all(); 4682 return; 4683 } 4684 4685 /* expr() is also called in global initializations */ 4686 if (dcs->d_kind != DLK_EXTERN && !is_do_while) 4687 check_statement_reachable(stmt_kind); 4688 4689 check_expr_misc(tn, vctx, cond, !cond, false, false, false); 4690 if (tn->tn_op == ASSIGN && !tn->tn_parenthesized) { 4691 if (hflag && cond) 4692 /* assignment in conditional context */ 4693 warning(159); 4694 } 4695 if (!modtab[tn->tn_op].m_has_side_effect) { 4696 /* 4697 * for left operands of COMMA this warning is already printed 4698 */ 4699 if (tn->tn_op != COMMA && !vctx && !cond) 4700 check_null_effect(tn); 4701 } 4702 debug_node(tn); 4703 4704 if (dofreeblk) 4705 expr_free_all(); 4706 } 4707 4708 /* If the expression has the form '*(arr + idx)', check the array index. */ 4709 static void 4710 check_array_index(const tnode_t *indir, bool taking_address) 4711 { 4712 const tnode_t *plus, *arr, *idx; 4713 4714 if (indir->tn_op == INDIR 4715 && (plus = indir->u.ops.left, plus->tn_op == PLUS) 4716 && plus->u.ops.left->tn_op == ADDR 4717 && (arr = plus->u.ops.left->u.ops.left, true) 4718 && (arr->tn_op == STRING || arr->tn_op == NAME) 4719 && arr->tn_type->t_tspec == ARRAY 4720 && (idx = plus->u.ops.right, idx->tn_op == CON) 4721 && (!is_incomplete(arr->tn_type) || idx->u.value.u.integer < 0)) 4722 goto proceed; 4723 return; 4724 4725 proceed:; 4726 int elsz = length_in_bits(arr->tn_type->t_subt, NULL); 4727 if (elsz == 0) 4728 return; 4729 elsz /= CHAR_SIZE; 4730 4731 /* Change the unit of the index from bytes to element size. */ 4732 int64_t con = is_uinteger(idx->tn_type->t_tspec) 4733 ? (int64_t)((uint64_t)idx->u.value.u.integer / elsz) 4734 : idx->u.value.u.integer / elsz; 4735 4736 int dim = arr->tn_type->u.dimension + (taking_address ? 1 : 0); 4737 4738 if (!is_uinteger(idx->tn_type->t_tspec) && con < 0) 4739 /* array subscript %jd cannot be negative */ 4740 warning(167, (intmax_t)con); 4741 else if (dim > 0 && (uint64_t)con >= (uint64_t)dim) 4742 /* array subscript %ju cannot be > %d */ 4743 warning(168, (uintmax_t)con, dim - 1); 4744 } 4745 4746 static void 4747 check_expr_addr(const tnode_t *ln, bool szof, bool fcall) 4748 { 4749 /* XXX: Taking warn_about_unreachable into account here feels wrong. */ 4750 if (ln->tn_op == NAME && (reached || !warn_about_unreachable)) { 4751 if (!szof) 4752 mark_as_set(ln->u.sym); 4753 mark_as_used(ln->u.sym, fcall, szof); 4754 } 4755 check_array_index(ln, true); 4756 } 4757 4758 /* 4759 * If there is an asm statement in one of the compound statements around, 4760 * there may be other side effects, so don't warn. 4761 */ 4762 static bool 4763 is_asm_around(void) 4764 { 4765 for (decl_level *dl = dcs; dl != NULL; dl = dl->d_enclosing) 4766 if (dl->d_asm) 4767 return true; 4768 return false; 4769 } 4770 4771 static void 4772 check_expr_side_effect(const tnode_t *ln, bool szof) 4773 { 4774 4775 /* XXX: Taking warn_about_unreachable into account here feels wrong. */ 4776 if (ln->tn_op == NAME && (reached || !warn_about_unreachable)) { 4777 scl_t sc = ln->u.sym->s_scl; 4778 if (sc != EXTERN && sc != STATIC && 4779 !ln->u.sym->s_set && !szof && !is_asm_around()) { 4780 /* '%s' may be used before set */ 4781 warning(158, ln->u.sym->s_name); 4782 mark_as_set(ln->u.sym); 4783 } 4784 mark_as_used(ln->u.sym, false, false); 4785 } 4786 } 4787 4788 static void 4789 check_expr_assign(const tnode_t *ln, bool szof) 4790 { 4791 /* XXX: Taking warn_about_unreachable into account here feels wrong. */ 4792 if (ln->tn_op == NAME && !szof && (reached || !warn_about_unreachable)) { 4793 mark_as_set(ln->u.sym); 4794 if (ln->u.sym->s_scl == EXTERN) 4795 outusg(ln->u.sym); 4796 } 4797 check_array_index(ln, false); 4798 } 4799 4800 static void 4801 check_expr_call(const tnode_t *tn, const tnode_t *ln, 4802 bool szof, bool vctx, bool cond, bool retval_discarded) 4803 { 4804 lint_assert(ln->tn_op == ADDR); 4805 lint_assert(ln->u.ops.left->tn_op == NAME); 4806 if (!szof && !is_compiler_builtin(ln->u.ops.left->u.sym->s_name)) 4807 outcall(tn, vctx || cond, retval_discarded); 4808 4809 const function_call *call = tn->u.call; 4810 if (call->args_len == 4 || call->args_len == 5) 4811 check_snprintb(call); 4812 } 4813 4814 static void 4815 check_expr_op(op_t op, const tnode_t *ln, bool szof, bool fcall, bool eqwarn) 4816 { 4817 switch (op) { 4818 case ADDR: 4819 check_expr_addr(ln, szof, fcall); 4820 break; 4821 case LOAD: 4822 check_array_index(ln, false); 4823 /* FALLTHROUGH */ 4824 case INCBEF: 4825 case DECBEF: 4826 case INCAFT: 4827 case DECAFT: 4828 case ADDASS: 4829 case SUBASS: 4830 case MULASS: 4831 case DIVASS: 4832 case MODASS: 4833 case ANDASS: 4834 case ORASS: 4835 case XORASS: 4836 case SHLASS: 4837 case SHRASS: 4838 case REAL: 4839 case IMAG: 4840 check_expr_side_effect(ln, szof); 4841 break; 4842 case ASSIGN: 4843 check_expr_assign(ln, szof); 4844 break; 4845 case EQ: 4846 if (hflag && eqwarn) 4847 /* operator '==' found where '=' was expected */ 4848 warning(160); 4849 break; 4850 default: 4851 break; 4852 } 4853 } 4854 4855 /* 4856 * vctx ??? 4857 * cond whether the expression is a condition that 4858 * will be compared with 0 4859 * eqwarn whether the operator '==' might be a 4860 * misspelled '=' 4861 * fcall whether the expression is a function call 4862 * retval_discarded whether the return value of a function call 4863 * is discarded; such calls will be analyzed by 4864 * lint2 in messages 4, 8 and 9 4865 * szof whether the expression is part of a sizeof 4866 * expression, which means that its value is 4867 * discarded since only the type is relevant 4868 */ 4869 void 4870 check_expr_misc(const tnode_t *tn, bool vctx, bool cond, 4871 bool eqwarn, bool fcall, bool retval_discarded, bool szof) 4872 { 4873 4874 if (tn == NULL) 4875 return; 4876 op_t op = tn->tn_op; 4877 if (op == NAME || op == CON || op == STRING) 4878 return; 4879 bool is_direct = op == CALL 4880 && tn->u.call->func->tn_op == ADDR 4881 && tn->u.call->func->u.ops.left->tn_op == NAME; 4882 if (op == CALL) { 4883 const function_call *call = tn->u.call; 4884 if (is_direct) 4885 check_expr_call(tn, call->func, 4886 szof, vctx, cond, retval_discarded); 4887 bool discard = op == CVT && tn->tn_type->t_tspec == VOID; 4888 check_expr_misc(call->func, false, false, false, is_direct, 4889 discard, szof); 4890 for (size_t i = 0, n = call->args_len; i < n; i++) 4891 check_expr_misc(call->args[i], 4892 true, false, false, false, false, szof); 4893 return; 4894 } 4895 4896 lint_assert(has_operands(tn)); 4897 tnode_t *ln = tn->u.ops.left; 4898 tnode_t *rn = tn->u.ops.right; 4899 check_expr_op(op, ln, szof, fcall, eqwarn); 4900 4901 const mod_t *mp = &modtab[op]; 4902 bool cvctx = mp->m_value_context; 4903 bool ccond = mp->m_compares_with_zero; 4904 bool eq = mp->m_warn_if_operand_eq && 4905 !ln->tn_parenthesized && 4906 rn != NULL && !rn->tn_parenthesized; 4907 4908 /* 4909 * Values of operands of ':' are not used if the type of at least 4910 * one of the operands (for GCC compatibility) is 'void'. 4911 * 4912 * XXX test/value context of QUEST should probably be used as 4913 * context for both operands of COLON. 4914 */ 4915 if (op == COLON && tn->tn_type->t_tspec == VOID) 4916 cvctx = ccond = false; 4917 bool discard = op == CVT && tn->tn_type->t_tspec == VOID; 4918 check_expr_misc(ln, cvctx, ccond, eq, is_direct, discard, szof); 4919 4920 switch (op) { 4921 case LOGAND: 4922 case LOGOR: 4923 check_expr_misc(rn, false, true, eq, false, false, szof); 4924 break; 4925 case COLON: 4926 check_expr_misc(rn, cvctx, ccond, eq, false, false, szof); 4927 break; 4928 case COMMA: 4929 check_expr_misc(rn, vctx, cond, false, false, false, szof); 4930 break; 4931 default: 4932 if (mp->m_binary) 4933 check_expr_misc(rn, true, false, eq, false, false, 4934 szof); 4935 break; 4936 } 4937 } 4938 4939 /* 4940 * Return whether the expression can be used for static initialization. 4941 * 4942 * Constant initialization expressions must be constant or an address 4943 * of a static object with an optional offset. In the first case, 4944 * the result is returned in *offsp. In the second case, the static 4945 * object is returned in *symp and the offset in *offsp. 4946 * 4947 * The expression can consist of PLUS, MINUS, ADDR, NAME, STRING and 4948 * CON. Type conversions are allowed if they do not change binary 4949 * representation (including width). 4950 * 4951 * C99 6.6 "Constant expressions" 4952 * C99 6.7.8p4 restricts initializers for static storage duration 4953 */ 4954 bool 4955 constant_addr(const tnode_t *tn, const sym_t **symp, ptrdiff_t *offsp) 4956 { 4957 const sym_t *sym; 4958 ptrdiff_t offs1, offs2; 4959 tspec_t t, ot; 4960 4961 switch (tn->tn_op) { 4962 case MINUS: 4963 if (tn->u.ops.right->tn_op == CVT) 4964 return constant_addr(tn->u.ops.right, symp, offsp); 4965 else if (tn->u.ops.right->tn_op != CON) 4966 return false; 4967 /* FALLTHROUGH */ 4968 case PLUS: 4969 offs1 = offs2 = 0; 4970 if (tn->u.ops.left->tn_op == CON) { 4971 offs1 = (ptrdiff_t)tn->u.ops.left->u.value.u.integer; 4972 if (!constant_addr(tn->u.ops.right, &sym, &offs2)) 4973 return false; 4974 } else if (tn->u.ops.right->tn_op == CON) { 4975 offs2 = (ptrdiff_t)tn->u.ops.right->u.value.u.integer; 4976 if (tn->tn_op == MINUS) 4977 offs2 = -offs2; 4978 if (!constant_addr(tn->u.ops.left, &sym, &offs1)) 4979 return false; 4980 } else { 4981 return false; 4982 } 4983 *symp = sym; 4984 *offsp = offs1 + offs2; 4985 return true; 4986 case ADDR: 4987 if (tn->u.ops.left->tn_op == NAME) { 4988 *symp = tn->u.ops.left->u.sym; 4989 *offsp = 0; 4990 return true; 4991 } else { 4992 /* 4993 * If this were the front end of a compiler, we would 4994 * return a label instead of 0, at least if 4995 * 'tn->u.ops.left->tn_op == STRING'. 4996 */ 4997 *symp = NULL; 4998 *offsp = 0; 4999 return true; 5000 } 5001 case CVT: 5002 t = tn->tn_type->t_tspec; 5003 ot = tn->u.ops.left->tn_type->t_tspec; 5004 if ((!is_integer(t) && t != PTR) || 5005 (!is_integer(ot) && ot != PTR)) { 5006 return false; 5007 } 5008 #if 0 5009 /*- 5010 * consider: 5011 * struct foo { 5012 * unsigned char a; 5013 * } f = { 5014 * (unsigned char)(unsigned long) 5015 * (&(((struct foo *)0)->a)) 5016 * }; 5017 * since psize(unsigned long) != psize(unsigned char), 5018 * this fails. 5019 */ 5020 else if (psize(t) != psize(ot)) 5021 return -1; 5022 #endif 5023 return constant_addr(tn->u.ops.left, symp, offsp); 5024 default: 5025 return false; 5026 } 5027 } 5028 5029 /* Append s2 to s1, then free s2. */ 5030 buffer * 5031 cat_strings(buffer *s1, buffer *s2) 5032 { 5033 5034 if ((s1->data != NULL) != (s2->data != NULL)) { 5035 /* cannot concatenate wide and regular string literals */ 5036 error(292); 5037 return s1; 5038 } 5039 5040 if (s1->data != NULL) { 5041 while (s1->len + s2->len + 1 > s1->cap) 5042 s1->cap *= 2; 5043 s1->data = xrealloc(s1->data, s1->cap); 5044 memcpy(s1->data + s1->len, s2->data, s2->len + 1); 5045 free(s2->data); 5046 } 5047 s1->len += s2->len; 5048 free(s2); 5049 5050 return s1; 5051 } 5052 5053 5054 typedef struct stmt_expr { 5055 memory_pool se_mem; 5056 sym_t *se_sym; 5057 struct stmt_expr *se_enclosing; 5058 } stmt_expr; 5059 5060 static stmt_expr *stmt_exprs; 5061 5062 void 5063 begin_statement_expr(void) 5064 { 5065 debug_enter(); 5066 5067 stmt_expr *se = xmalloc(sizeof(*se)); 5068 se->se_mem = expr_save_memory(); 5069 se->se_sym = NULL; 5070 se->se_enclosing = stmt_exprs; 5071 stmt_exprs = se; 5072 } 5073 5074 void 5075 do_statement_expr(tnode_t *tn) 5076 { 5077 block_level--; 5078 mem_block_level--; 5079 stmt_exprs->se_sym = tn != NULL 5080 ? mktempsym(block_dup_type(tn->tn_type)) 5081 : NULL; /* after a syntax error */ 5082 mem_block_level++; 5083 block_level++; 5084 /* '({ ... })' is a GCC extension */ 5085 gnuism(320); 5086 } 5087 5088 tnode_t * 5089 end_statement_expr(void) 5090 { 5091 tnode_t *tn; 5092 5093 stmt_expr *se = stmt_exprs; 5094 if (se->se_sym == NULL) { 5095 tn = NULL; /* after a syntax error */ 5096 goto end; 5097 } 5098 5099 tn = build_name(se->se_sym, false); 5100 (void)expr_save_memory(); /* leak */ 5101 expr_restore_memory(se->se_mem); 5102 stmt_exprs = se->se_enclosing; 5103 free(se); 5104 5105 end: 5106 debug_leave(); 5107 return tn; 5108 } 5109 5110 bool 5111 in_statement_expr(void) 5112 { 5113 return stmt_exprs != NULL; 5114 } 5115
Indexes created Mon Sep 22 21:09:42 GMT 2025