tree.c revision 1.686
1 /* $NetBSD: tree.c,v 1.686 2025/07/11 19:03:01 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 1.686 2025/07/11 19:03:01 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 static size_t 606 str_len(const tnode_t *tn) 607 { 608 const buffer *buf = tn->u.str_literals; 609 if (tn->tn_type->t_subt->t_tspec != CHAR) 610 return buf->len; 611 quoted_iterator it = { .end = 0 }; 612 size_t len = 0; 613 while (quoted_next(buf, &it)) 614 len++; 615 return len; 616 } 617 618 /* Create an expression from a unary or binary operator and its operands. */ 619 static tnode_t * 620 build_op(op_t op, bool sys, type_t *type, tnode_t *ln, tnode_t *rn) 621 { 622 623 tnode_t *ntn = expr_alloc_tnode(); 624 ntn->tn_op = op; 625 ntn->tn_type = type; 626 ntn->tn_sys = sys; 627 ntn->u.ops.left = ln; 628 ntn->u.ops.right = rn; 629 630 if (op == INDIR || op == FSEL) { 631 lint_assert(ln->tn_type->t_tspec == PTR); 632 tspec_t t = ln->tn_type->t_subt->t_tspec; 633 ntn->tn_lvalue = t != FUNC && t != VOID; 634 } 635 636 return ntn; 637 } 638 639 tnode_t * 640 build_constant(type_t *tp, val_t *v) 641 { 642 643 tnode_t *n = expr_alloc_tnode(); 644 n->tn_op = CON; 645 n->tn_type = tp; 646 n->u.value = *v; 647 n->u.value.v_tspec = tp->t_tspec; 648 free(v); 649 return n; 650 } 651 652 static tnode_t * 653 build_integer_constant(tspec_t t, int64_t si) 654 { 655 656 tnode_t *n = expr_alloc_tnode(); 657 n->tn_op = CON; 658 n->tn_type = gettyp(t); 659 n->u.value.v_tspec = t; 660 n->u.value.v_unsigned_since_c90 = false; 661 n->u.value.v_char_constant = false; 662 n->u.value.u.integer = si; 663 return n; 664 } 665 666 static void 667 fallback_symbol(sym_t *sym) 668 { 669 670 if (Tflag && fallback_symbol_strict_bool(sym)) 671 return; 672 673 if (funcsym != NULL && (strcmp(sym->s_name, "__FUNCTION__") == 0 || 674 strcmp(sym->s_name, "__PRETTY_FUNCTION__") == 0)) { 675 /* __FUNCTION__/__PRETTY_FUNCTION__ is a GCC extension */ 676 gnuism(316); 677 goto return_function_name; 678 } 679 680 if (funcsym != NULL && strcmp(sym->s_name, "__func__") == 0) { 681 if (!allow_c99) 682 /* __func__ is a C99 feature */ 683 warning(317); 684 /* C11 6.4.2.2 */ 685 return_function_name: 686 sym->s_type = block_derive_type(gettyp(CHAR), ARRAY); 687 sym->s_type->t_const = true; 688 sym->s_type->u.dimension = (int)strlen(funcsym->s_name) + 1; 689 return; 690 } 691 692 /* '%s' undefined */ 693 error(99, sym->s_name); 694 } 695 696 /* 697 * Functions that are predeclared by GCC or other compilers can be called 698 * with arbitrary arguments. Since lint usually runs after a successful 699 * compilation, it's the compiler's job to catch any errors. 700 */ 701 bool 702 is_compiler_builtin(const char *name) 703 { 704 /* https://gcc.gnu.org/onlinedocs/gcc/C-Extensions.html */ 705 if (allow_gcc) { 706 if (strncmp(name, "__atomic_", 9) == 0 || 707 strncmp(name, "__builtin_", 10) == 0 || 708 strcmp(name, "alloca") == 0 || 709 /* obsolete but still in use, as of 2021 */ 710 strncmp(name, "__sync_", 7) == 0) 711 return true; 712 } 713 714 /* https://software.intel.com/sites/landingpage/IntrinsicsGuide/ */ 715 if (strncmp(name, "_mm_", 4) == 0) 716 return true; 717 718 return false; 719 } 720 721 static bool 722 str_ends_with(const char *haystack, const char *needle) 723 { 724 size_t hlen = strlen(haystack); 725 size_t nlen = strlen(needle); 726 727 return nlen <= hlen && 728 memcmp(haystack + hlen - nlen, needle, nlen) == 0; 729 } 730 731 /* https://gcc.gnu.org/onlinedocs/gcc/Integer-Overflow-Builtins.html */ 732 static bool 733 is_gcc_bool_builtin(const char *name) 734 { 735 return strncmp(name, "__builtin_", 10) == 0 && 736 (str_ends_with(name, "_overflow") || 737 str_ends_with(name, "_overflow_p")); 738 } 739 740 static void 741 build_name_call(sym_t *sym) 742 { 743 744 if (is_compiler_builtin(sym->s_name)) { 745 /* 746 * Do not warn about these, just assume that they are regular 747 * functions compatible with non-prototype calling conventions. 748 */ 749 if (allow_gcc && is_gcc_bool_builtin(sym->s_name)) 750 sym->s_type = gettyp(BOOL); 751 } else if (allow_c99) 752 /* function '%s' implicitly declared to return int */ 753 error(215, sym->s_name); 754 else if (!allow_trad) 755 /* function '%s' implicitly declared to return int */ 756 warning(215, sym->s_name); 757 758 /* XXX if !allow_c90, the symbol should be exported to level 0 */ 759 sym->s_type = block_derive_type(sym->s_type, FUNC); 760 } 761 762 /* Create a node for a name (symbol table entry). */ 763 tnode_t * 764 build_name(sym_t *sym, bool is_funcname) 765 { 766 767 if (sym->s_scl == NO_SCL && !in_gcc_attribute) { 768 sym->s_scl = EXTERN; 769 sym->s_def = DECL; 770 if (is_funcname) 771 build_name_call(sym); 772 else 773 fallback_symbol(sym); 774 } 775 776 lint_assert(sym->s_kind == SK_VCFT || sym->s_kind == SK_MEMBER); 777 778 tnode_t *n = expr_alloc_tnode(); 779 n->tn_type = sym->s_type; 780 if (sym->s_scl == BOOL_CONST) { 781 n->tn_op = CON; 782 n->u.value.v_tspec = BOOL; 783 n->u.value.v_unsigned_since_c90 = false; 784 n->u.value.v_char_constant = false; 785 n->u.value.u.integer = sym->u.s_bool_constant ? 1 : 0; 786 } else if (sym->s_scl == ENUM_CONST) { 787 n->tn_op = CON; 788 n->u.value.v_tspec = INT; /* ENUM is in n->tn_type */ 789 n->u.value.v_unsigned_since_c90 = false; 790 n->u.value.v_char_constant = false; 791 n->u.value.u.integer = sym->u.s_enum_constant; 792 } else { 793 n->tn_op = NAME; 794 n->u.sym = sym; 795 if (sym->s_kind == SK_VCFT && sym->s_type->t_tspec != FUNC) 796 n->tn_lvalue = true; 797 } 798 799 return n; 800 } 801 802 tnode_t * 803 build_string(buffer *lit) 804 { 805 size_t value_len = lit->len; 806 if (lit->data != NULL) { 807 quoted_iterator it = { .end = 0 }; 808 for (value_len = 0; quoted_next(lit, &it); value_len++) 809 continue; 810 } 811 812 type_t *tp = expr_zero_alloc(sizeof(*tp), "type"); 813 tp->t_tspec = ARRAY; 814 tp->t_subt = gettyp(lit->data != NULL ? CHAR : WCHAR_TSPEC); 815 tp->u.dimension = (int)(value_len + 1); 816 817 tnode_t *n = expr_alloc_tnode(); 818 n->tn_op = STRING; 819 n->tn_type = tp; 820 n->tn_lvalue = true; 821 822 n->u.str_literals = expr_zero_alloc(sizeof(*n->u.str_literals), "tnode.string"); 823 n->u.str_literals->len = lit->len; 824 825 if (lit->data != NULL) { 826 n->u.str_literals->data = expr_zero_alloc(lit->len + 1, 827 "tnode.string.data"); 828 (void)memcpy(n->u.str_literals->data, lit->data, lit->len + 1); 829 free(lit->data); 830 } 831 free(lit); 832 833 return n; 834 } 835 836 tnode_t * 837 build_generic_selection(const tnode_t *expr, 838 struct generic_association *sel) 839 { 840 tnode_t *default_result = NULL; 841 842 for (; sel != NULL; sel = sel->ga_prev) { 843 if (expr != NULL && 844 types_compatible(sel->ga_arg, expr->tn_type, 845 false, false, NULL)) 846 return sel->ga_result; 847 if (sel->ga_arg == NULL) 848 default_result = sel->ga_result; 849 } 850 return default_result; 851 } 852 853 static bool 854 is_out_of_char_range(const tnode_t *tn) 855 { 856 return tn->tn_op == CON && 857 !tn->u.value.v_char_constant && 858 !(0 <= tn->u.value.u.integer && 859 tn->u.value.u.integer < 1 << (CHAR_SIZE - 1)); 860 } 861 862 static bool 863 check_nonportable_char_comparison(op_t op, 864 const tnode_t *ln, tspec_t lt, 865 const tnode_t *rn, tspec_t rt) 866 { 867 if (!(hflag || pflag)) 868 return true; 869 870 if (lt == CHAR && is_out_of_char_range(rn)) { 871 char buf[128]; 872 (void)snprintf(buf, sizeof(buf), "%s %d", 873 op_name(op), (int)rn->u.value.u.integer); 874 /* nonportable character comparison '%s' */ 875 warning(230, buf); 876 return false; 877 } 878 if (rt == CHAR && is_out_of_char_range(ln)) { 879 char buf[128]; 880 (void)snprintf(buf, sizeof(buf), "%d %s ?", 881 (int)ln->u.value.u.integer, op_name(op)); 882 /* nonportable character comparison '%s' */ 883 warning(230, buf); 884 return false; 885 } 886 return true; 887 } 888 889 static void 890 check_integer_comparison(op_t op, tnode_t *ln, tnode_t *rn) 891 { 892 893 tspec_t lt = ln->tn_type->t_tspec; 894 tspec_t rt = rn->tn_type->t_tspec; 895 896 if (ln->tn_op != CON && rn->tn_op != CON) 897 return; 898 899 if (!is_integer(lt) || !is_integer(rt)) 900 return; 901 902 if (any_query_enabled && !in_system_header) { 903 if (lt == CHAR && rn->tn_op == CON && 904 !rn->u.value.v_char_constant) { 905 /* comparison '%s' of 'char' with plain integer %d */ 906 query_message(14, 907 op_name(op), (int)rn->u.value.u.integer); 908 } 909 if (rt == CHAR && ln->tn_op == CON && 910 !ln->u.value.v_char_constant) { 911 /* comparison '%s' of 'char' with plain integer %d */ 912 query_message(14, 913 op_name(op), (int)ln->u.value.u.integer); 914 } 915 } 916 917 if (!check_nonportable_char_comparison(op, ln, lt, rn, rt)) 918 return; 919 920 if (is_uinteger(lt) && !is_uinteger(rt) && 921 rn->tn_op == CON && rn->u.value.u.integer <= 0) { 922 if (rn->u.value.u.integer < 0) { 923 /* operator '%s' compares '%s' with '%s' */ 924 warning(162, op_name(op), 925 type_name(ln->tn_type), "negative constant"); 926 } else if (op == LT || op == GE) 927 /* operator '%s' compares '%s' with '%s' */ 928 warning(162, op_name(op), type_name(ln->tn_type), "0"); 929 return; 930 } 931 if (is_uinteger(rt) && !is_uinteger(lt) && 932 ln->tn_op == CON && ln->u.value.u.integer <= 0) { 933 if (ln->u.value.u.integer < 0) { 934 /* operator '%s' compares '%s' with '%s' */ 935 warning(162, op_name(op), 936 "negative constant", type_name(rn->tn_type)); 937 } else if (op == GT || op == LE) 938 /* operator '%s' compares '%s' with '%s' */ 939 warning(162, op_name(op), "0", type_name(rn->tn_type)); 940 return; 941 } 942 } 943 944 static const tspec_t arith_rank[] = { 945 LDOUBLE, DOUBLE, FLOAT, 946 #ifdef INT128_SIZE 947 UINT128, INT128, 948 #endif 949 ULLONG, LLONG, 950 ULONG, LONG, 951 UINT, INT, 952 }; 953 954 /* Keep unsigned in traditional C */ 955 static tspec_t 956 usual_arithmetic_conversion_trad(tspec_t lt, tspec_t rt) 957 { 958 959 size_t i; 960 for (i = 0; arith_rank[i] != INT; i++) 961 if (lt == arith_rank[i] || rt == arith_rank[i]) 962 break; 963 964 tspec_t t = arith_rank[i]; 965 if (is_uinteger(lt) || is_uinteger(rt)) 966 if (is_integer(t) && !is_uinteger(t)) 967 return unsigned_type(t); 968 return t; 969 } 970 971 static tspec_t 972 usual_arithmetic_conversion_c90(tspec_t lt, tspec_t rt) 973 { 974 975 if (lt == rt) 976 return lt; 977 978 if (lt == LCOMPLEX || rt == LCOMPLEX) 979 return LCOMPLEX; 980 if (lt == DCOMPLEX || rt == DCOMPLEX) 981 return DCOMPLEX; 982 if (lt == FCOMPLEX || rt == FCOMPLEX) 983 return FCOMPLEX; 984 if (lt == LDOUBLE || rt == LDOUBLE) 985 return LDOUBLE; 986 if (lt == DOUBLE || rt == DOUBLE) 987 return DOUBLE; 988 if (lt == FLOAT || rt == FLOAT) 989 return FLOAT; 990 991 if (size_in_bits(lt) > size_in_bits(rt)) 992 return lt; 993 if (size_in_bits(lt) < size_in_bits(rt)) 994 return rt; 995 996 size_t i; 997 for (i = 3; arith_rank[i] != INT; i++) 998 if (arith_rank[i] == lt || arith_rank[i] == rt) 999 break; 1000 if ((is_uinteger(lt) || is_uinteger(rt)) && 1001 !is_uinteger(arith_rank[i])) 1002 i--; 1003 return arith_rank[i]; 1004 } 1005 1006 static tnode_t * 1007 apply_usual_arithmetic_conversions(op_t op, tnode_t *tn, tspec_t t) 1008 { 1009 type_t *ntp = expr_dup_type(tn->tn_type); 1010 ntp->t_tspec = t; 1011 if (tn->tn_op != CON) { 1012 /* usual arithmetic conversion for '%s' from '%s' to '%s' */ 1013 query_message(4, op_name(op), 1014 type_name(tn->tn_type), type_name(ntp)); 1015 } 1016 return convert(op, 0, ntp, tn); 1017 } 1018 1019 /* 1020 * Apply the "usual arithmetic conversions" (C99 6.3.1.8), which gives both 1021 * operands the same type. 1022 */ 1023 static void 1024 balance(op_t op, tnode_t **lnp, tnode_t **rnp) 1025 { 1026 1027 tspec_t lt = (*lnp)->tn_type->t_tspec; 1028 tspec_t rt = (*rnp)->tn_type->t_tspec; 1029 if (!is_arithmetic(lt) || !is_arithmetic(rt)) 1030 return; 1031 1032 tspec_t t = allow_c90 1033 ? usual_arithmetic_conversion_c90(lt, rt) 1034 : usual_arithmetic_conversion_trad(lt, rt); 1035 1036 if (modtab[op].m_comparison 1037 && is_integer(lt) && (*lnp)->tn_op != CON 1038 && is_floating(t) && (*rnp)->tn_op == CON) 1039 /* comparing integer '%s' to floating point constant %Lg */ 1040 warning(379, type_name((*lnp)->tn_type), 1041 (*rnp)->u.value.u.floating); 1042 1043 if (t != lt) 1044 *lnp = apply_usual_arithmetic_conversions(op, *lnp, t); 1045 if (t != rt) 1046 *rnp = apply_usual_arithmetic_conversions(op, *rnp, t); 1047 1048 if (is_integer(t)) { 1049 unsigned lw = width_in_bits((*lnp)->tn_type); 1050 unsigned rw = width_in_bits((*rnp)->tn_type); 1051 if (lw < rw) 1052 *lnp = convert(NOOP, 0, (*rnp)->tn_type, *lnp); 1053 if (rw < lw) 1054 *rnp = convert(NOOP, 0, (*lnp)->tn_type, *rnp); 1055 } 1056 } 1057 1058 static tnode_t * 1059 build_address(bool sys, tnode_t *tn) 1060 { 1061 /* eliminate '&*' */ 1062 if (tn->tn_op == INDIR && 1063 tn->u.ops.left->tn_type->t_tspec == PTR && 1064 tn->u.ops.left->tn_type->t_subt == tn->tn_type) { 1065 return tn->u.ops.left; 1066 } 1067 1068 return build_op(ADDR, sys, expr_derive_type(tn->tn_type, PTR), 1069 tn, NULL); 1070 } 1071 1072 static uint64_t 1073 fold_unsigned_integer(op_t op, uint64_t l, uint64_t r, 1074 uint64_t max_value, bool *overflow) 1075 { 1076 switch (op) { 1077 case COMPL: 1078 return ~l & max_value; 1079 case UPLUS: 1080 return +l; 1081 case UMINUS: 1082 return -l & max_value; 1083 case MULT: 1084 *overflow = r > 0 && l > max_value / r; 1085 return l * r; 1086 case DIV: 1087 if (r == 0) { 1088 /* division by 0 */ 1089 error(139); 1090 return max_value; 1091 } 1092 return l / r; 1093 case MOD: 1094 if (r == 0) { 1095 /* modulus by 0 */ 1096 error(140); 1097 return 0; 1098 } 1099 return l % r; 1100 case PLUS: 1101 *overflow = l > max_value - r; 1102 return l + r; 1103 case MINUS: 1104 *overflow = l < r; 1105 return l - r; 1106 case SHL: 1107 /* TODO: warn about out-of-bounds 'r'. */ 1108 /* TODO: warn about overflow. */ 1109 return l << (r & 63); 1110 case SHR: 1111 /* TODO: warn about out-of-bounds 'r'. */ 1112 return l >> (r & 63); 1113 case LT: 1114 return l < r ? 1 : 0; 1115 case LE: 1116 return l <= r ? 1 : 0; 1117 case GT: 1118 return l > r ? 1 : 0; 1119 case GE: 1120 return l >= r ? 1 : 0; 1121 case EQ: 1122 return l == r ? 1 : 0; 1123 case NE: 1124 return l != r ? 1 : 0; 1125 case BITAND: 1126 return l & r; 1127 case BITXOR: 1128 return l ^ r; 1129 case BITOR: 1130 return l | r; 1131 default: 1132 lint_assert(false); 1133 /* NOTREACHED */ 1134 } 1135 } 1136 1137 static int64_t 1138 fold_signed_integer(op_t op, int64_t l, int64_t r, 1139 int64_t min_value, int64_t max_value, bool *overflow) 1140 { 1141 switch (op) { 1142 case COMPL: 1143 return ~l; 1144 case UPLUS: 1145 return +l; 1146 case UMINUS: 1147 *overflow = l == min_value; 1148 return *overflow ? l : -l; 1149 case MULT:; 1150 uint64_t al = s64_abs(l); 1151 uint64_t ar = s64_abs(r); 1152 bool neg = (l >= 0) != (r >= 0); 1153 uint64_t max_prod = (uint64_t)max_value + (neg ? 1 : 0); 1154 if (al > 0 && ar > max_prod / al) { 1155 *overflow = true; 1156 return neg ? min_value : max_value; 1157 } 1158 return l * r; 1159 case DIV: 1160 if (r == 0) { 1161 /* division by 0 */ 1162 error(139); 1163 return max_value; 1164 } 1165 if (l == min_value && r == -1) { 1166 *overflow = true; 1167 return l; 1168 } 1169 return l / r; 1170 case MOD: 1171 if (r == 0) { 1172 /* modulus by 0 */ 1173 error(140); 1174 return 0; 1175 } 1176 if (l == min_value && r == -1) { 1177 *overflow = true; 1178 return 0; 1179 } 1180 return l % r; 1181 case PLUS: 1182 if (r > 0 && l > max_value - r) { 1183 *overflow = true; 1184 return max_value; 1185 } 1186 if (r < 0 && l < min_value - r) { 1187 *overflow = true; 1188 return min_value; 1189 } 1190 return l + r; 1191 case MINUS: 1192 if (r > 0 && l < min_value + r) { 1193 *overflow = true; 1194 return min_value; 1195 } 1196 if (r < 0 && l > max_value + r) { 1197 *overflow = true; 1198 return max_value; 1199 } 1200 return l - r; 1201 case SHL: 1202 /* TODO: warn about out-of-bounds 'r'. */ 1203 /* TODO: warn about overflow. */ 1204 return l << (r & 63); 1205 case SHR: 1206 /* TODO: warn about out-of-bounds 'r'. */ 1207 return s64_shr(l, r & 63); 1208 case LT: 1209 return l < r ? 1 : 0; 1210 case LE: 1211 return l <= r ? 1 : 0; 1212 case GT: 1213 return l > r ? 1 : 0; 1214 case GE: 1215 return l >= r ? 1 : 0; 1216 case EQ: 1217 return l == r ? 1 : 0; 1218 case NE: 1219 return l != r ? 1 : 0; 1220 case BITAND: 1221 return l & r; 1222 case BITXOR: 1223 return l ^ r; 1224 case BITOR: 1225 return l | r; 1226 default: 1227 lint_assert(false); 1228 /* NOTREACHED */ 1229 } 1230 } 1231 1232 static tnode_t * 1233 fold_constant_integer(tnode_t *tn) 1234 { 1235 1236 lint_assert(has_operands(tn)); 1237 tspec_t t = tn->u.ops.left->tn_type->t_tspec; 1238 int64_t l = tn->u.ops.left->u.value.u.integer; 1239 int64_t r = is_binary(tn) ? tn->u.ops.right->u.value.u.integer : 0; 1240 uint64_t mask = value_bits(size_in_bits(t)); 1241 1242 int64_t res; 1243 bool overflow = false; 1244 if (!is_integer(t) || is_uinteger(t)) { 1245 uint64_t u_res = fold_unsigned_integer(tn->tn_op, 1246 (uint64_t)l, (uint64_t)r, mask, &overflow); 1247 if (u_res > mask) 1248 overflow = true; 1249 res = (int64_t)u_res; 1250 if (overflow && hflag) { 1251 char buf[128]; 1252 if (is_binary(tn)) { 1253 snprintf(buf, sizeof(buf), "%ju %s %ju", 1254 (uintmax_t)l, op_name(tn->tn_op), 1255 (uintmax_t)r); 1256 } else { 1257 snprintf(buf, sizeof(buf), "%s%ju", 1258 op_name(tn->tn_op), (uintmax_t)l); 1259 } 1260 /* '%s' overflows '%s' */ 1261 warning(141, buf, type_name(tn->tn_type)); 1262 } 1263 } else { 1264 int64_t max_value = (int64_t)(mask >> 1); 1265 int64_t min_value = -max_value - 1; 1266 res = fold_signed_integer(tn->tn_op, 1267 l, r, min_value, max_value, &overflow); 1268 if (res < min_value || res > max_value) 1269 overflow = true; 1270 if (overflow && hflag) { 1271 char buf[128]; 1272 if (is_binary(tn)) { 1273 snprintf(buf, sizeof(buf), "%jd %s %jd", 1274 (intmax_t)l, op_name(tn->tn_op), 1275 (intmax_t)r); 1276 } else if (tn->tn_op == UMINUS && l < 0) { 1277 snprintf(buf, sizeof(buf), "-(%jd)", 1278 (intmax_t)l); 1279 } else { 1280 snprintf(buf, sizeof(buf), "%s%jd", 1281 op_name(tn->tn_op), (intmax_t)l); 1282 } 1283 /* '%s' overflows '%s' */ 1284 warning(141, buf, type_name(tn->tn_type)); 1285 } 1286 } 1287 1288 val_t *v = xcalloc(1, sizeof(*v)); 1289 v->v_tspec = tn->tn_type->t_tspec; 1290 v->u.integer = convert_integer(res, t, size_in_bits(t)); 1291 1292 tnode_t *cn = build_constant(tn->tn_type, v); 1293 if (tn->u.ops.left->tn_system_dependent) 1294 cn->tn_system_dependent = true; 1295 if (is_binary(tn) && tn->u.ops.right->tn_system_dependent) 1296 cn->tn_system_dependent = true; 1297 1298 return cn; 1299 } 1300 1301 static tnode_t * 1302 build_struct_access(op_t op, bool sys, tnode_t *ln, tnode_t *rn) 1303 { 1304 1305 lint_assert(rn->tn_op == NAME); 1306 lint_assert(is_member(rn->u.sym)); 1307 1308 bool lvalue = op == ARROW || ln->tn_lvalue; 1309 1310 if (op == POINT) 1311 ln = build_address(sys, ln); 1312 else if (ln->tn_type->t_tspec != PTR) { 1313 lint_assert(!allow_c90); 1314 lint_assert(is_integer(ln->tn_type->t_tspec)); 1315 ln = convert(NOOP, 0, expr_derive_type(gettyp(VOID), PTR), ln); 1316 } 1317 1318 tnode_t *ctn = build_integer_constant(PTRDIFF_TSPEC, 1319 rn->u.sym->u.s_member.sm_offset_in_bits / CHAR_SIZE); 1320 1321 type_t *ptr_tp = expr_derive_type(rn->tn_type, PTR); 1322 tnode_t *ntn = build_op(PLUS, sys, ptr_tp, ln, ctn); 1323 if (ln->tn_op == CON) 1324 ntn = fold_constant_integer(ntn); 1325 1326 op_t nop = rn->tn_type->t_bitfield ? FSEL : INDIR; 1327 ntn = build_op(nop, sys, ntn->tn_type->t_subt, ntn, NULL); 1328 if (!lvalue) 1329 ntn->tn_lvalue = false; 1330 1331 return ntn; 1332 } 1333 1334 /* 1335 * Get the size in bytes of type tp->t_subt, as a constant expression of type 1336 * ptrdiff_t as seen from the target platform. 1337 */ 1338 static tnode_t * 1339 subt_size_in_bytes(type_t *tp) 1340 { 1341 1342 lint_assert(tp->t_tspec == PTR); 1343 tp = tp->t_subt; 1344 1345 int elem = 1; 1346 while (tp->t_tspec == ARRAY) { 1347 elem *= tp->u.dimension; 1348 tp = tp->t_subt; 1349 } 1350 1351 int elsz_in_bits = 0; 1352 switch (tp->t_tspec) { 1353 case FUNC: 1354 /* pointer to function is not allowed here */ 1355 error(110); 1356 break; 1357 case VOID: 1358 /* cannot do pointer arithmetic on operand of unknown size */ 1359 gnuism(136); 1360 break; 1361 case STRUCT: 1362 case UNION: 1363 if ((elsz_in_bits = (int)tp->u.sou->sou_size_in_bits) == 0) 1364 /* cannot do pointer arithmetic on operand of ... */ 1365 error(136); 1366 break; 1367 case ENUM: 1368 if (is_incomplete(tp)) 1369 /* cannot do pointer arithmetic on operand of ... */ 1370 warning(136); 1371 /* FALLTHROUGH */ 1372 default: 1373 if ((elsz_in_bits = size_in_bits(tp->t_tspec)) == 0) 1374 /* cannot do pointer arithmetic on operand of ... */ 1375 error(136); 1376 else 1377 lint_assert(elsz_in_bits != -1); 1378 break; 1379 } 1380 1381 if (elem == 0 && elsz_in_bits != 0) 1382 /* cannot do pointer arithmetic on operand of unknown size */ 1383 error(136); 1384 1385 if (elsz_in_bits == 0) 1386 elsz_in_bits = CHAR_SIZE; 1387 1388 return build_integer_constant(PTRDIFF_TSPEC, 1389 (int64_t)(elem * elsz_in_bits / CHAR_SIZE)); 1390 } 1391 1392 static tnode_t * 1393 build_prepost_incdec(op_t op, bool sys, tnode_t *ln) 1394 { 1395 1396 lint_assert(ln != NULL); 1397 tnode_t *cn = ln->tn_type->t_tspec == PTR 1398 ? subt_size_in_bytes(ln->tn_type) 1399 : build_integer_constant(INT, 1); 1400 return build_op(op, sys, ln->tn_type, ln, cn); 1401 } 1402 1403 static void 1404 check_enum_array_index(const tnode_t *ln, const tnode_t *rn) 1405 { 1406 1407 if (ln->tn_op != ADDR) 1408 return; 1409 ln = ln->u.ops.left; 1410 if (ln->tn_op != NAME && ln->tn_op != STRING) 1411 return; 1412 1413 const type_t *ltp = ln->tn_type; 1414 if (ltp->t_tspec != ARRAY || ltp->t_incomplete_array) 1415 return; 1416 1417 if (rn->tn_op != CVT || !rn->tn_type->t_is_enum) 1418 return; 1419 if (rn->u.ops.left->tn_op != LOAD) 1420 return; 1421 1422 const type_t *rtp = rn->u.ops.left->tn_type; 1423 const sym_t *ec = rtp->u.enumer->en_first_enumerator; 1424 const sym_t *max_ec = ec; 1425 lint_assert(ec != NULL); 1426 for (ec = ec->s_next; ec != NULL; ec = ec->s_next) 1427 if (ec->u.s_enum_constant > max_ec->u.s_enum_constant) 1428 max_ec = ec; 1429 1430 int64_t max_enum_value = max_ec->u.s_enum_constant; 1431 lint_assert(INT_MIN <= max_enum_value && max_enum_value <= INT_MAX); 1432 1433 int max_array_index = ltp->u.dimension - 1; 1434 size_t nonnull_dimension = ln->tn_op == STRING 1435 ? str_len(ln) 1436 : ln->u.sym->u.s_array_nonnull_dimension; 1437 if (nonnull_dimension > 0) 1438 max_array_index = (int)nonnull_dimension - 1; 1439 if (max_enum_value == max_array_index) 1440 return; 1441 1442 if (max_enum_value == max_array_index + 1 && 1443 (strstr(max_ec->s_name, "MAX") != NULL || 1444 strstr(max_ec->s_name, "max") != NULL || 1445 strstr(max_ec->s_name, "NUM") != NULL || 1446 strstr(max_ec->s_name, "num") != NULL || 1447 strncmp(max_ec->s_name, "N_", 2) == 0)) 1448 return; 1449 1450 /* maximum value %d for '%s' of type '%s' does not match maximum array index %d */ 1451 warning(348, (int)max_enum_value, max_ec->s_name, type_name(rtp), 1452 max_array_index); 1453 print_previous_declaration(max_ec); 1454 } 1455 1456 static tnode_t * 1457 build_plus_minus(op_t op, bool sys, tnode_t *ln, tnode_t *rn) 1458 { 1459 1460 if (rn->tn_type->t_tspec == PTR && is_integer(ln->tn_type->t_tspec)) { 1461 tnode_t *tmp = ln; 1462 ln = rn; 1463 rn = tmp; 1464 /* pointer addition has integer on the left-hand side */ 1465 query_message(5); 1466 } 1467 1468 /* pointer +- integer */ 1469 tspec_t lt = ln->tn_type->t_tspec; 1470 tspec_t rt = rn->tn_type->t_tspec; 1471 if (lt == PTR && rt != PTR) { 1472 lint_assert(is_integer(rt)); 1473 1474 check_ctype_macro_invocation(ln, rn); 1475 check_enum_array_index(ln, rn); 1476 1477 tnode_t *elsz = subt_size_in_bytes(ln->tn_type); 1478 tspec_t szt = elsz->tn_type->t_tspec; 1479 if (rt != szt && rt != unsigned_type(szt)) 1480 rn = convert(NOOP, 0, elsz->tn_type, rn); 1481 1482 tnode_t *prod = build_op(MULT, sys, rn->tn_type, rn, elsz); 1483 if (rn->tn_op == CON) 1484 prod = fold_constant_integer(prod); 1485 1486 return build_op(op, sys, ln->tn_type, ln, prod); 1487 } 1488 1489 /* pointer - pointer */ 1490 if (rt == PTR) { 1491 lint_assert(lt == PTR); 1492 lint_assert(op == MINUS); 1493 1494 type_t *ptrdiff = gettyp(PTRDIFF_TSPEC); 1495 tnode_t *raw_diff = build_op(op, sys, ptrdiff, ln, rn); 1496 if (ln->tn_op == CON && rn->tn_op == CON) 1497 raw_diff = fold_constant_integer(raw_diff); 1498 1499 tnode_t *elsz = subt_size_in_bytes(ln->tn_type); 1500 balance(NOOP, &raw_diff, &elsz); 1501 1502 return build_op(DIV, sys, ptrdiff, raw_diff, elsz); 1503 } 1504 1505 return build_op(op, sys, ln->tn_type, ln, rn); 1506 } 1507 1508 static tnode_t * 1509 build_bit_shift(op_t op, bool sys, tnode_t *ln, tnode_t *rn) 1510 { 1511 1512 if (!allow_c90 && rn->tn_type->t_tspec != INT) 1513 // XXX: C1978 7.5 says: "Both [operators] perform the usual 1514 // arithmetic conversions on their operands." 1515 // TODO: Add a test to exercise this part of the code. 1516 rn = convert(NOOP, 0, gettyp(INT), rn); 1517 return build_op(op, sys, ln->tn_type, ln, rn); 1518 } 1519 1520 static bool 1521 is_null_pointer(const tnode_t *tn) 1522 { 1523 tspec_t t = tn->tn_type->t_tspec; 1524 1525 // TODO: Investigate how other pointers are stored, in particular, 1526 // whether a pointer constant can have a non-zero value. 1527 // If not, simplify the code below. 1528 return ((t == PTR && tn->tn_type->t_subt->t_tspec == VOID) 1529 || is_integer(t)) 1530 && (tn->tn_op == CON && tn->u.value.u.integer == 0); 1531 } 1532 1533 /* Return a type based on tp1, with added qualifiers from tp2. */ 1534 static type_t * 1535 merge_qualifiers(type_t *tp1, const type_t *tp2) 1536 { 1537 1538 lint_assert(tp1->t_tspec == PTR); 1539 lint_assert(tp2->t_tspec == PTR); 1540 1541 bool c1 = tp1->t_subt->t_const; 1542 bool c2 = tp2->t_subt->t_const; 1543 bool v1 = tp1->t_subt->t_volatile; 1544 bool v2 = tp2->t_subt->t_volatile; 1545 1546 if (c1 == (c1 | c2) && v1 == (v1 | v2)) 1547 return tp1; 1548 1549 type_t *nstp = expr_dup_type(tp1->t_subt); 1550 nstp->t_const |= c2; 1551 nstp->t_volatile |= v2; 1552 1553 type_t *ntp = expr_dup_type(tp1); 1554 ntp->t_subt = nstp; 1555 return ntp; 1556 } 1557 1558 /* See C99 6.5.15 "Conditional operator". */ 1559 static tnode_t * 1560 build_colon(bool sys, tnode_t *ln, tnode_t *rn) 1561 { 1562 tspec_t lt = ln->tn_type->t_tspec; 1563 tspec_t rt = rn->tn_type->t_tspec; 1564 1565 type_t *tp; 1566 if (is_arithmetic(lt) && is_arithmetic(rt)) 1567 /* The operands were already balanced in build_binary. */ 1568 tp = ln->tn_type; 1569 else if (lt == BOOL && rt == BOOL) 1570 tp = ln->tn_type; 1571 else if (lt == VOID || rt == VOID) 1572 tp = gettyp(VOID); 1573 else if (is_struct_or_union(lt)) { 1574 lint_assert(is_struct_or_union(rt)); 1575 lint_assert(ln->tn_type->u.sou == rn->tn_type->u.sou); 1576 if (is_incomplete(ln->tn_type)) { 1577 /* unknown operand size, op '%s' */ 1578 error(138, op_name(COLON)); 1579 return NULL; 1580 } 1581 tp = ln->tn_type; 1582 } else if (lt == PTR && is_integer(rt)) { 1583 if (rt != PTRDIFF_TSPEC) 1584 rn = convert(NOOP, 0, gettyp(PTRDIFF_TSPEC), rn); 1585 tp = ln->tn_type; 1586 } else if (rt == PTR && is_integer(lt)) { 1587 if (lt != PTRDIFF_TSPEC) 1588 ln = convert(NOOP, 0, gettyp(PTRDIFF_TSPEC), ln); 1589 tp = rn->tn_type; 1590 } else if (lt == PTR && is_null_pointer(rn)) 1591 tp = merge_qualifiers(ln->tn_type, rn->tn_type); 1592 else if (rt == PTR && is_null_pointer(ln)) 1593 tp = merge_qualifiers(rn->tn_type, ln->tn_type); 1594 else if (lt == PTR && ln->tn_type->t_subt->t_tspec == VOID) 1595 tp = merge_qualifiers(ln->tn_type, rn->tn_type); 1596 else if (rt == PTR && rn->tn_type->t_subt->t_tspec == VOID) 1597 tp = merge_qualifiers(rn->tn_type, ln->tn_type); 1598 else { 1599 /* 1600 * XXX For now we simply take the left type. This is probably 1601 * wrong, if one type contains a function prototype and the 1602 * other one, at the same place, only an old-style declaration. 1603 */ 1604 tp = merge_qualifiers(ln->tn_type, rn->tn_type); 1605 } 1606 1607 return build_op(COLON, sys, tp, ln, rn); 1608 } 1609 1610 /* TODO: check for varargs */ 1611 static bool 1612 is_cast_redundant(const tnode_t *tn) 1613 { 1614 const type_t *ntp = tn->tn_type, *otp = tn->u.ops.left->tn_type; 1615 tspec_t nt = ntp->t_tspec, ot = otp->t_tspec; 1616 1617 if (nt == BOOL || ot == BOOL) 1618 return nt == BOOL && ot == BOOL; 1619 1620 if (is_integer(nt) && is_integer(ot)) { 1621 unsigned int nw = width_in_bits(ntp), ow = width_in_bits(otp); 1622 if (is_uinteger(nt) == is_uinteger(ot)) 1623 return nw >= ow; 1624 return is_uinteger(ot) && nw > ow; 1625 } 1626 1627 if (is_complex(nt) || is_complex(ot)) 1628 return is_complex(nt) && is_complex(ot) && 1629 size_in_bits(nt) >= size_in_bits(ot); 1630 1631 if (is_floating(nt) && is_floating(ot)) 1632 return size_in_bits(nt) >= size_in_bits(ot); 1633 1634 if (nt == PTR && ot == PTR) { 1635 if (!ntp->t_subt->t_const && otp->t_subt->t_const) 1636 return false; 1637 if (!ntp->t_subt->t_volatile && otp->t_subt->t_volatile) 1638 return false; 1639 1640 if (ntp->t_subt->t_tspec == VOID || 1641 otp->t_subt->t_tspec == VOID || 1642 types_compatible(ntp->t_subt, otp->t_subt, 1643 false, false, NULL)) 1644 return true; 1645 } 1646 1647 return false; 1648 } 1649 1650 static bool 1651 is_assignment(op_t op) 1652 { 1653 1654 return op == ASSIGN || 1655 op == MULASS || 1656 op == DIVASS || 1657 op == MODASS || 1658 op == ADDASS || 1659 op == SUBASS || 1660 op == SHLASS || 1661 op == SHRASS || 1662 op == ANDASS || 1663 op == XORASS || 1664 op == ORASS || 1665 op == RETURN || 1666 op == INIT; 1667 } 1668 1669 static tnode_t * 1670 build_assignment(op_t op, bool sys, tnode_t *ln, tnode_t *rn) 1671 { 1672 1673 tspec_t lt = ln->tn_type->t_tspec; 1674 tspec_t rt = rn->tn_type->t_tspec; 1675 1676 if (is_assignment(rn->tn_op)) 1677 /* chained assignment with '%s' and '%s' */ 1678 query_message(10, op_name(op), op_name(rn->tn_op)); 1679 1680 if ((op == ADDASS || op == SUBASS) && lt == PTR) { 1681 lint_assert(is_integer(rt)); 1682 tnode_t *ctn = subt_size_in_bytes(ln->tn_type); 1683 if (rn->tn_type->t_tspec != ctn->tn_type->t_tspec) 1684 rn = convert(NOOP, 0, ctn->tn_type, rn); 1685 rn = build_op(MULT, sys, rn->tn_type, rn, ctn); 1686 if (rn->u.ops.left->tn_op == CON) 1687 rn = fold_constant_integer(rn); 1688 } 1689 1690 if ((op == ASSIGN || op == RETURN || op == INIT) && 1691 (lt == STRUCT || rt == STRUCT)) { 1692 lint_assert(lt == rt); 1693 lint_assert(ln->tn_type->u.sou == rn->tn_type->u.sou); 1694 if (is_incomplete(ln->tn_type)) { 1695 if (op == RETURN) 1696 /* cannot return incomplete type */ 1697 error(212); 1698 else 1699 /* unknown operand size, op '%s' */ 1700 error(138, op_name(op)); 1701 return NULL; 1702 } 1703 } 1704 1705 if (op == SHLASS && hflag && allow_trad && allow_c90 1706 && portable_rank_cmp(lt, rt) < 0) 1707 /* semantics of '%s' change in C90; ... */ 1708 warning(118, "<<="); 1709 1710 if (op != SHLASS && op != SHRASS 1711 && (op == ASSIGN || lt != PTR) 1712 && (lt != rt || (ln->tn_type->t_bitfield && rn->tn_op == CON))) { 1713 rn = convert(op, 0, ln->tn_type, rn); 1714 rt = lt; 1715 } 1716 1717 if (lt == PTR && ln->tn_type->t_subt->t_tspec != VOID 1718 && rt == PTR && rn->tn_type->t_subt->t_tspec == VOID 1719 && !is_null_pointer(rn)) 1720 /* implicit narrowing conversion from void ... */ 1721 query_message(20, type_name(ln->tn_type)); 1722 1723 if (any_query_enabled && rn->tn_op == CVT && rn->tn_cast && 1724 types_compatible(ln->tn_type, rn->tn_type, false, false, NULL) && 1725 is_cast_redundant(rn)) { 1726 /* redundant cast from '%s' to '%s' before assignment */ 1727 query_message(7, type_name(rn->u.ops.left->tn_type), 1728 type_name(rn->tn_type)); 1729 } 1730 1731 return build_op(op, sys, ln->tn_type, ln, rn); 1732 } 1733 1734 static tnode_t * 1735 build_real_imag(op_t op, bool sys, tnode_t *ln) 1736 { 1737 1738 lint_assert(ln != NULL); 1739 if (ln->tn_op == NAME) { 1740 /* 1741 * This may be too much, but it avoids wrong warnings. See 1742 * d_c99_complex_split.c. 1743 */ 1744 mark_as_used(ln->u.sym, false, false); 1745 mark_as_set(ln->u.sym); 1746 } 1747 1748 tspec_t t; 1749 switch (ln->tn_type->t_tspec) { 1750 case LCOMPLEX: 1751 t = LDOUBLE; 1752 break; 1753 case DCOMPLEX: 1754 t = DOUBLE; 1755 break; 1756 case FCOMPLEX: 1757 t = FLOAT; 1758 break; 1759 default: 1760 /* '__%s__' is invalid for type '%s' */ 1761 error(276, op == REAL ? "real" : "imag", 1762 type_name(ln->tn_type)); 1763 return NULL; 1764 } 1765 1766 tnode_t *ntn = build_op(op, sys, gettyp(t), ln, NULL); 1767 ntn->tn_lvalue = true; 1768 return ntn; 1769 } 1770 1771 static bool 1772 is_confusing_precedence(op_t op, const tnode_t *operand, op_t *cop) 1773 { 1774 if (operand->tn_parenthesized) 1775 return false; 1776 op_t oop = operand->tn_op; 1777 1778 if (op == SHL || op == SHR) { 1779 if (oop == PLUS || oop == MINUS) 1780 return *cop = oop, true; 1781 return false; 1782 } 1783 1784 if (op == LOGOR) { 1785 if (oop == LOGAND) 1786 return *cop = oop, true; 1787 return false; 1788 } 1789 1790 lint_assert(op == BITAND || op == BITXOR || op == BITOR); 1791 if (oop != op 1792 && (oop == PLUS || oop == MINUS || oop == BITAND || oop == BITXOR)) 1793 return *cop = oop, true; 1794 return false; 1795 } 1796 1797 /* 1798 * Print a warning if the given node has operands which should be 1799 * parenthesized. 1800 * 1801 * XXX Does not work if an operand is a constant expression. Constant 1802 * expressions are already folded. 1803 */ 1804 static void 1805 check_precedence_confusion(tnode_t *tn) 1806 { 1807 tnode_t *ln, *rn; 1808 1809 if (!hflag) 1810 return; 1811 1812 debug_node(tn); 1813 1814 lint_assert(is_binary(tn)); 1815 for (ln = tn->u.ops.left; ln->tn_op == CVT; ln = ln->u.ops.left) 1816 continue; 1817 for (rn = tn->u.ops.right; rn->tn_op == CVT; rn = rn->u.ops.left) 1818 continue; 1819 1820 op_t cop; 1821 if (is_confusing_precedence(tn->tn_op, ln, &cop) || 1822 is_confusing_precedence(tn->tn_op, rn, &cop)) { 1823 /* possible precedence confusion between '%s' and '%s' */ 1824 warning(169, op_name(tn->tn_op), op_name(cop)); 1825 } 1826 } 1827 1828 static tnode_t * 1829 fold_constant_compare_zero(tnode_t *tn) 1830 { 1831 1832 val_t *v = xcalloc(1, sizeof(*v)); 1833 v->v_tspec = tn->tn_type->t_tspec; 1834 lint_assert(v->v_tspec == INT || (Tflag && v->v_tspec == BOOL)); 1835 1836 lint_assert(has_operands(tn)); 1837 bool l = constant_is_nonzero(tn->u.ops.left); 1838 bool r = is_binary(tn) && constant_is_nonzero(tn->u.ops.right); 1839 1840 switch (tn->tn_op) { 1841 case NOT: 1842 v->u.integer = !l ? 1 : 0; 1843 break; 1844 case LOGAND: 1845 v->u.integer = l && r ? 1 : 0; 1846 break; 1847 case LOGOR: 1848 v->u.integer = l || r ? 1 : 0; 1849 break; 1850 default: 1851 lint_assert(false); 1852 } 1853 1854 return build_constant(tn->tn_type, v); 1855 } 1856 1857 static long double 1858 floating_error_value(tspec_t t, long double lv) 1859 { 1860 if (t == FLOAT) 1861 return lv < 0 ? -FLT_MAX : FLT_MAX; 1862 if (t == DOUBLE) 1863 return lv < 0 ? -DBL_MAX : DBL_MAX; 1864 /* 1865 * When NetBSD is cross-built in MKLINT=yes mode on x86_64 for sparc64, 1866 * tools/lint checks this code while building usr.bin/xlint. In that 1867 * situation, lint uses the preprocessor for sparc64, in which the type 1868 * 'long double' is IEEE-754-binary128, affecting the macro LDBL_MAX 1869 * below. The type 'long double', as well as the strtold 1870 * implementation, comes from the host platform x86_64 though, where 1871 * 'long double' consumes 128 bits as well but only uses 80 of them. 1872 * The exponent range of the two 'long double' types is the same, but 1873 * the maximum finite value differs due to the extended precision on 1874 * sparc64. 1875 * 1876 * To properly handle the data types of the target platform, lint would 1877 * have to implement the floating-point types in a platform-independent 1878 * way, which is not worth the effort, given how few programs 1879 * practically use 'long double'. 1880 */ 1881 /* LINTED 248: floating-point constant out of range */ 1882 long double max = LDBL_MAX; 1883 return lv < 0 ? -max : max; 1884 } 1885 1886 static bool 1887 is_floating_overflow(tspec_t t, long double val) 1888 { 1889 if (fpe != 0 || isfinite(val) == 0) 1890 return true; 1891 if (t == FLOAT && (val > FLT_MAX || val < -FLT_MAX)) 1892 return true; 1893 if (t == DOUBLE && (val > DBL_MAX || val < -DBL_MAX)) 1894 return true; 1895 return false; 1896 } 1897 1898 static tnode_t * 1899 fold_constant_floating(tnode_t *tn) 1900 { 1901 1902 fpe = 0; 1903 1904 tspec_t t = tn->tn_type->t_tspec; 1905 1906 val_t *v = xcalloc(1, sizeof(*v)); 1907 v->v_tspec = t; 1908 1909 lint_assert(is_floating(t)); 1910 lint_assert(has_operands(tn)); 1911 lint_assert(t == tn->u.ops.left->tn_type->t_tspec); 1912 lint_assert(!is_binary(tn) || t == tn->u.ops.right->tn_type->t_tspec); 1913 1914 long double lv = tn->u.ops.left->u.value.u.floating; 1915 long double rv = is_binary(tn) ? tn->u.ops.right->u.value.u.floating 1916 : 0.0; 1917 1918 switch (tn->tn_op) { 1919 case UPLUS: 1920 v->u.floating = lv; 1921 break; 1922 case UMINUS: 1923 v->u.floating = -lv; 1924 break; 1925 case MULT: 1926 v->u.floating = lv * rv; 1927 break; 1928 case DIV: 1929 if (rv == 0.0) { 1930 /* division by 0 */ 1931 error(139); 1932 v->u.floating = floating_error_value(t, lv); 1933 } else { 1934 v->u.floating = lv / rv; 1935 } 1936 break; 1937 case PLUS: 1938 v->u.floating = lv + rv; 1939 break; 1940 case MINUS: 1941 v->u.floating = lv - rv; 1942 break; 1943 case LT: 1944 v->u.integer = lv < rv ? 1 : 0; 1945 break; 1946 case LE: 1947 v->u.integer = lv <= rv ? 1 : 0; 1948 break; 1949 case GE: 1950 v->u.integer = lv >= rv ? 1 : 0; 1951 break; 1952 case GT: 1953 v->u.integer = lv > rv ? 1 : 0; 1954 break; 1955 case EQ: 1956 v->u.integer = lv == rv ? 1 : 0; 1957 break; 1958 case NE: 1959 v->u.integer = lv != rv ? 1 : 0; 1960 break; 1961 default: 1962 lint_assert(false); 1963 } 1964 1965 // XXX: Must not access u.floating after setting u.integer. 1966 lint_assert(fpe != 0 || isnan(v->u.floating) == 0); 1967 if (is_complex(v->v_tspec)) { 1968 /* 1969 * Don't warn, as lint doesn't model the imaginary part of 1970 * complex numbers. 1971 */ 1972 fpe = 0; 1973 } else if (is_floating_overflow(t, v->u.floating)) { 1974 /* operator '%s' produces floating point overflow */ 1975 warning(142, op_name(tn->tn_op)); 1976 v->u.floating = floating_error_value(t, v->u.floating); 1977 fpe = 0; 1978 } 1979 1980 return build_constant(tn->tn_type, v); 1981 } 1982 1983 static void 1984 use(const tnode_t *tn) 1985 { 1986 if (tn == NULL) 1987 return; 1988 switch (tn->tn_op) { 1989 case NAME: 1990 mark_as_used(tn->u.sym, false /* XXX */, false /* XXX */); 1991 break; 1992 case CON: 1993 case STRING: 1994 break; 1995 case CALL:; 1996 const function_call *call = tn->u.call; 1997 for (size_t i = 0, n = call->args_len; i < n; i++) 1998 use(call->args[i]); 1999 break; 2000 default: 2001 lint_assert(has_operands(tn)); 2002 use(tn->u.ops.left); 2003 if (is_binary(tn)) 2004 use(tn->u.ops.right); 2005 } 2006 } 2007 2008 /* 2009 * Create a tree node for a binary operator and its two operands. Also called 2010 * for unary operators; in that case rn is NULL. 2011 * 2012 * Function calls, sizeof and casts are handled elsewhere. 2013 */ 2014 tnode_t * 2015 build_binary(tnode_t *ln, op_t op, bool sys, tnode_t *rn) 2016 { 2017 const mod_t *mp = &modtab[op]; 2018 2019 /* If there was an error in one of the operands, return. */ 2020 if (ln == NULL || (mp->m_binary && rn == NULL)) 2021 return NULL; 2022 2023 if (mp->m_value_context || mp->m_compares_with_zero) 2024 ln = cconv(ln); 2025 if (mp->m_binary && op != ARROW && op != POINT) 2026 rn = cconv(rn); 2027 2028 if (mp->m_comparison) 2029 check_integer_comparison(op, ln, rn); 2030 2031 if (mp->m_value_context || mp->m_compares_with_zero) 2032 ln = promote(op, false, ln); 2033 if (mp->m_binary && op != ARROW && op != POINT && 2034 op != ASSIGN && op != RETURN && op != INIT) 2035 rn = promote(op, false, rn); 2036 2037 if (mp->m_warn_if_left_unsigned_in_c90 && 2038 ln->tn_op == CON && ln->u.value.v_unsigned_since_c90) { 2039 /* C90 treats constant as unsigned, op '%s' */ 2040 warning(218, op_name(op)); 2041 ln->u.value.v_unsigned_since_c90 = false; 2042 } 2043 if (mp->m_warn_if_right_unsigned_in_c90 && 2044 rn->tn_op == CON && rn->u.value.v_unsigned_since_c90) { 2045 /* C90 treats constant as unsigned, op '%s' */ 2046 warning(218, op_name(op)); 2047 rn->u.value.v_unsigned_since_c90 = false; 2048 } 2049 2050 if (mp->m_balance_operands || (!allow_c90 && (op == SHL || op == SHR))) 2051 balance(op, &ln, &rn); 2052 2053 if (!typeok(op, NULL, 0, ln, rn)) 2054 return NULL; 2055 2056 tnode_t *ntn; 2057 switch (op) { 2058 case POINT: 2059 case ARROW: 2060 ntn = build_struct_access(op, sys, ln, rn); 2061 break; 2062 case INCAFT: 2063 case DECAFT: 2064 case INCBEF: 2065 case DECBEF: 2066 ntn = build_prepost_incdec(op, sys, ln); 2067 break; 2068 case ADDR: 2069 ntn = build_address(sys, ln); 2070 break; 2071 case INDIR: 2072 ntn = build_op(INDIR, sys, ln->tn_type->t_subt, ln, NULL); 2073 break; 2074 case PLUS: 2075 case MINUS: 2076 ntn = build_plus_minus(op, sys, ln, rn); 2077 break; 2078 case SHL: 2079 case SHR: 2080 ntn = build_bit_shift(op, sys, ln, rn); 2081 break; 2082 case COLON: 2083 ntn = build_colon(sys, ln, rn); 2084 break; 2085 case ASSIGN: 2086 case MULASS: 2087 case DIVASS: 2088 case MODASS: 2089 case ADDASS: 2090 case SUBASS: 2091 case SHLASS: 2092 case SHRASS: 2093 case ANDASS: 2094 case XORASS: 2095 case ORASS: 2096 case RETURN: 2097 case INIT: 2098 ntn = build_assignment(op, sys, ln, rn); 2099 break; 2100 case COMMA: 2101 /* comma operator with types '%s' and '%s' */ 2102 query_message(12, 2103 type_name(ln->tn_type), type_name(rn->tn_type)); 2104 /* FALLTHROUGH */ 2105 case QUEST: 2106 ntn = build_op(op, sys, rn->tn_type, ln, rn); 2107 break; 2108 case REAL: 2109 case IMAG: 2110 ntn = build_real_imag(op, sys, ln); 2111 break; 2112 default: 2113 lint_assert(mp->m_binary == (rn != NULL)); 2114 if ((op == NOT || op == LOGAND || op == LOGOR) 2115 && ln->tn_op == ASSIGN && ln->u.ops.right->tn_op == CON) { 2116 /* constant assignment of type '%s' in operand ... */ 2117 warning(382, type_name(ln->tn_type), op_name(op), 2118 is_nonzero_val(&ln->u.ops.right->u.value) 2119 ? "true" : "false"); 2120 } 2121 if ((op == LOGAND || op == LOGOR) 2122 && rn->tn_op == ASSIGN && rn->u.ops.right->tn_op == CON) { 2123 /* constant assignment of type '%s' in operand ... */ 2124 warning(382, type_name(rn->tn_type), op_name(op), 2125 is_nonzero_val(&rn->u.ops.right->u.value) 2126 ? "true" : "false"); 2127 } 2128 type_t *rettp = mp->m_returns_bool 2129 ? gettyp(Tflag ? BOOL : INT) : ln->tn_type; 2130 ntn = build_op(op, sys, rettp, ln, rn); 2131 break; 2132 } 2133 2134 if (ntn == NULL) 2135 return NULL; 2136 2137 if (mp->m_possible_precedence_confusion) 2138 check_precedence_confusion(ntn); 2139 2140 if (mp->m_fold_constant_operands && ln->tn_op == CON) { 2141 if (!mp->m_binary || rn->tn_op == CON) { 2142 if (mp->m_compares_with_zero) 2143 ntn = fold_constant_compare_zero(ntn); 2144 else if (is_floating(ntn->tn_type->t_tspec)) 2145 ntn = fold_constant_floating(ntn); 2146 else 2147 ntn = fold_constant_integer(ntn); 2148 } else if (op == QUEST) { 2149 lint_assert(has_operands(rn)); 2150 use(ln->u.value.u.integer != 0 2151 ? rn->u.ops.right : rn->u.ops.left); 2152 ntn = ln->u.value.u.integer != 0 2153 ? rn->u.ops.left : rn->u.ops.right; 2154 } 2155 } 2156 2157 return ntn; 2158 } 2159 2160 tnode_t * 2161 build_unary(op_t op, bool sys, tnode_t *tn) 2162 { 2163 return build_binary(tn, op, sys, NULL); 2164 } 2165 2166 static bool 2167 are_members_compatible(const sym_t *a, const sym_t *b) 2168 { 2169 if (a->u.s_member.sm_offset_in_bits != b->u.s_member.sm_offset_in_bits) 2170 return false; 2171 2172 const type_t *atp = a->s_type; 2173 const type_t *btp = b->s_type; 2174 bool w = false; 2175 if (!types_compatible(atp, btp, false, false, &w) && !w) 2176 return false; 2177 if (a->s_bitfield != b->s_bitfield) 2178 return false; 2179 if (a->s_bitfield) { 2180 if (atp->t_bit_field_width != btp->t_bit_field_width) 2181 return false; 2182 if (atp->t_bit_field_offset != btp->t_bit_field_offset) 2183 return false; 2184 } 2185 return true; 2186 } 2187 2188 /* 2189 * Return whether all struct/union members with the same name have the same 2190 * type and offset. 2191 */ 2192 static bool 2193 all_members_compatible(const sym_t *msym) 2194 { 2195 for (const sym_t *csym = msym; 2196 csym != NULL; csym = csym->s_symtab_next) { 2197 if (!is_member(csym)) 2198 continue; 2199 if (strcmp(msym->s_name, csym->s_name) != 0) 2200 continue; 2201 2202 for (const sym_t *sym = csym->s_symtab_next; 2203 sym != NULL; sym = sym->s_symtab_next) { 2204 if (is_member(sym) 2205 && strcmp(csym->s_name, sym->s_name) == 0 2206 && !are_members_compatible(csym, sym)) 2207 return false; 2208 } 2209 } 2210 return true; 2211 } 2212 2213 sym_t * 2214 find_member(const struct_or_union *sou, const char *name) 2215 { 2216 for (sym_t *mem = sou->sou_first_member; 2217 mem != NULL; mem = mem->s_next) { 2218 lint_assert(is_member(mem)); 2219 lint_assert(mem->u.s_member.sm_containing_type == sou); 2220 if (strcmp(mem->s_name, name) == 0) 2221 return mem; 2222 } 2223 2224 for (sym_t *mem = sou->sou_first_member; 2225 mem != NULL; mem = mem->s_next) { 2226 if (is_struct_or_union(mem->s_type->t_tspec) 2227 && mem->s_name == unnamed) { 2228 sym_t *nested_mem = 2229 find_member(mem->s_type->u.sou, name); 2230 if (nested_mem != NULL) 2231 return nested_mem; 2232 } 2233 } 2234 return NULL; 2235 } 2236 2237 /* 2238 * Remove the member if it was unknown until now, which means 2239 * that no defined struct or union has a member with the same name. 2240 */ 2241 static void 2242 remove_unknown_member(tnode_t *tn, sym_t *msym) 2243 { 2244 /* type '%s' does not have member '%s' */ 2245 error(101, type_name(tn->tn_type), msym->s_name); 2246 symtab_remove_forever(msym); 2247 msym->s_kind = SK_MEMBER; 2248 msym->s_scl = STRUCT_MEMBER; 2249 2250 struct_or_union *sou = expr_zero_alloc(sizeof(*sou), 2251 "struct_or_union"); 2252 sou->sou_tag = expr_zero_alloc(sizeof(*sou->sou_tag), "sym"); 2253 sou->sou_tag->s_name = unnamed; 2254 2255 msym->u.s_member.sm_containing_type = sou; 2256 /* 2257 * The member sm_offset_in_bits is not needed here since this symbol 2258 * can only be used for error reporting. 2259 */ 2260 } 2261 2262 /* 2263 * Returns a symbol which has the same name as 'msym' and is a member of the 2264 * struct or union specified by 'tn'. 2265 */ 2266 static sym_t * 2267 struct_or_union_member(tnode_t *tn, op_t op, sym_t *msym) 2268 { 2269 2270 /* Determine the tag type of which msym is expected to be a member. */ 2271 const type_t *tp = NULL; 2272 if (op == POINT && is_struct_or_union(tn->tn_type->t_tspec)) 2273 tp = tn->tn_type; 2274 if (op == ARROW && tn->tn_type->t_tspec == PTR 2275 && is_struct_or_union(tn->tn_type->t_subt->t_tspec)) 2276 tp = tn->tn_type->t_subt; 2277 struct_or_union *sou = tp != NULL ? tp->u.sou : NULL; 2278 2279 if (sou != NULL) { 2280 sym_t *nested_mem = find_member(sou, msym->s_name); 2281 if (nested_mem != NULL) 2282 return nested_mem; 2283 } 2284 2285 if (msym->s_scl == NO_SCL) { 2286 remove_unknown_member(tn, msym); 2287 return msym; 2288 } 2289 2290 bool eq = all_members_compatible(msym); 2291 2292 /* 2293 * Now handle the case in which the left operand refers really to a 2294 * struct/union, but the right operand is not member of it. 2295 */ 2296 if (sou != NULL) { 2297 if (eq && !allow_c90) 2298 /* invalid use of member '%s' */ 2299 warning(102, msym->s_name); 2300 else 2301 /* invalid use of member '%s' */ 2302 error(102, msym->s_name); 2303 return msym; 2304 } 2305 2306 if (eq) { 2307 if (op == POINT) { 2308 if (!allow_c90) 2309 /* left operand of '.' must be struct ... */ 2310 warning(103, type_name(tn->tn_type)); 2311 else 2312 /* left operand of '.' must be struct ... */ 2313 error(103, type_name(tn->tn_type)); 2314 } else { 2315 if (!allow_c90 && tn->tn_type->t_tspec == PTR) 2316 /* left operand of '->' must be pointer ... */ 2317 warning(104, type_name(tn->tn_type)); 2318 else 2319 /* left operand of '->' must be pointer ... */ 2320 error(104, type_name(tn->tn_type)); 2321 } 2322 } else { 2323 if (!allow_c90) 2324 /* non-unique member requires struct/union %s */ 2325 error(105, op == POINT ? "object" : "pointer"); 2326 else 2327 /* unacceptable operand of '%s' */ 2328 error(111, op_name(op)); 2329 } 2330 2331 return msym; 2332 } 2333 2334 tnode_t * 2335 build_member_access(tnode_t *ln, op_t op, bool sys, sbuf_t *member) 2336 { 2337 sym_t *msym; 2338 2339 if (ln == NULL) 2340 return NULL; 2341 2342 if (op == ARROW) 2343 /* must do this before struct_or_union_member is called */ 2344 ln = cconv(ln); 2345 msym = struct_or_union_member(ln, op, getsym(member)); 2346 return build_binary(ln, op, sys, build_name(msym, false)); 2347 } 2348 2349 /* 2350 * Perform class conversions. 2351 * 2352 * Arrays of type T are converted into pointers to type T. 2353 * Functions are converted to pointers to functions. 2354 * Lvalues are converted to rvalues. 2355 * 2356 * C99 6.3 "Conversions" 2357 * C99 6.3.2 "Other operands" 2358 * C99 6.3.2.1 "Lvalues, arrays, and function designators" 2359 */ 2360 tnode_t * 2361 cconv(tnode_t *tn) 2362 { 2363 if (tn->tn_type->t_tspec == ARRAY) { 2364 if (!tn->tn_lvalue) { 2365 /* XXX print correct operator */ 2366 /* %soperand of '%s' must be lvalue */ 2367 gnuism(114, "", op_name(ADDR)); 2368 } 2369 tn = build_op(ADDR, tn->tn_sys, 2370 expr_derive_type(tn->tn_type->t_subt, PTR), tn, NULL); 2371 } 2372 2373 if (tn->tn_type->t_tspec == FUNC) 2374 tn = build_address(tn->tn_sys, tn); 2375 2376 if (tn->tn_lvalue) { 2377 type_t *tp = expr_dup_type(tn->tn_type); 2378 /* C99 6.3.2.1p2 sentence 2 says to remove the qualifiers. */ 2379 tp->t_const = tp->t_volatile = false; 2380 tn = build_op(LOAD, tn->tn_sys, tp, tn, NULL); 2381 } 2382 2383 return tn; 2384 } 2385 2386 const tnode_t * 2387 before_conversion(const tnode_t *tn) 2388 { 2389 while (tn->tn_op == CVT && !tn->tn_cast) 2390 tn = tn->u.ops.left; 2391 return tn; 2392 } 2393 2394 /* 2395 * Most errors required by C90 are reported in struct_or_union_member(). 2396 * Here we only check for totally wrong things. 2397 */ 2398 static bool 2399 typeok_point(const tnode_t *ln, const type_t *ltp, tspec_t lt) 2400 { 2401 if (is_struct_or_union(lt)) 2402 return true; 2403 2404 if (lt == FUNC || lt == VOID || ltp->t_bitfield) 2405 goto wrong; 2406 2407 /* 2408 * Some C dialects from before C90 tolerated any lvalue on the 2409 * left-hand side of the '.' operator, allowing things like 'char 2410 * st[100]; st.st_mtime', assuming that the member 'st_mtime' only 2411 * occurred in a single struct; see typeok_arrow. 2412 */ 2413 if (ln->tn_lvalue) 2414 return true; 2415 2416 wrong: 2417 /* With allow_c90 we already got an error */ 2418 if (!allow_c90) 2419 /* unacceptable operand of '%s' */ 2420 error(111, op_name(POINT)); 2421 2422 return false; 2423 } 2424 2425 static bool 2426 typeok_arrow(tspec_t lt) 2427 { 2428 /* 2429 * C1978 Appendix A 14.1 says: <quote>In fact, any lvalue is allowed 2430 * before '.', and that lvalue is then assumed to have the form of the 2431 * structure of which the name of the right is a member. [...] Such 2432 * constructions are non-portable.</quote> 2433 */ 2434 if (lt == PTR || (!allow_c90 && is_integer(lt))) 2435 return true; 2436 2437 /* With allow_c90 we already got an error */ 2438 if (!allow_c90) 2439 /* unacceptable operand of '%s' */ 2440 error(111, op_name(ARROW)); 2441 return false; 2442 } 2443 2444 static bool 2445 typeok_incdec(op_t op, const tnode_t *tn, const type_t *tp) 2446 { 2447 /* operand has scalar type (checked in typeok) */ 2448 if (!tn->tn_lvalue) { 2449 if (tn->tn_op == CVT && tn->tn_cast && 2450 tn->u.ops.left->tn_op == LOAD) 2451 /* a cast does not yield an lvalue */ 2452 error(163); 2453 /* %soperand of '%s' must be lvalue */ 2454 error(114, "", op_name(op)); 2455 return false; 2456 } 2457 if (tp->t_const && allow_c90) 2458 /* %soperand of '%s' must be modifiable lvalue */ 2459 warning(115, "", op_name(op)); 2460 return true; 2461 } 2462 2463 static bool 2464 typeok_address(op_t op, const tnode_t *tn, const type_t *tp, tspec_t t) 2465 { 2466 if (t == ARRAY || t == FUNC) { 2467 /* ok, a warning comes later (in build_address()) */ 2468 } else if (!tn->tn_lvalue) { 2469 if (tn->tn_op == CVT && tn->tn_cast && 2470 tn->u.ops.left->tn_op == LOAD) 2471 /* a cast does not yield an lvalue */ 2472 error(163); 2473 /* %soperand of '%s' must be lvalue */ 2474 error(114, "", op_name(op)); 2475 return false; 2476 } else if (is_scalar(t)) { 2477 if (tp->t_bitfield) { 2478 /* cannot take address of bit-field */ 2479 error(112); 2480 return false; 2481 } 2482 } else if (t != STRUCT && t != UNION) { 2483 /* unacceptable operand of '%s' */ 2484 error(111, op_name(op)); 2485 return false; 2486 } 2487 if (tn->tn_op == NAME && tn->u.sym->s_register) { 2488 /* cannot take address of register '%s' */ 2489 error(113, tn->u.sym->s_name); 2490 return false; 2491 } 2492 return true; 2493 } 2494 2495 static bool 2496 typeok_indir(const type_t *tp, tspec_t t) 2497 { 2498 2499 if (t != PTR) { 2500 /* cannot dereference non-pointer type '%s' */ 2501 error(96, type_name(tp)); 2502 return false; 2503 } 2504 return true; 2505 } 2506 2507 static void 2508 warn_incompatible_types(op_t op, 2509 const type_t *ltp, tspec_t lt, 2510 const type_t *rtp, tspec_t rt) 2511 { 2512 bool binary = modtab[op].m_binary; 2513 2514 if (lt == VOID || (binary && rt == VOID)) { 2515 /* void type invalid in expression */ 2516 error(109); 2517 } else if (op == ASSIGN) 2518 /* cannot assign to '%s' from '%s' */ 2519 error(171, type_name(ltp), type_name(rtp)); 2520 else if (binary) 2521 /* operands of '%s' have incompatible types '%s' and '%s' */ 2522 error(107, op_name(op), type_name(ltp), type_name(rtp)); 2523 else { 2524 lint_assert(rt == NO_TSPEC); 2525 /* operand of '%s' has invalid type '%s' */ 2526 error(108, op_name(op), type_name(ltp)); 2527 } 2528 } 2529 2530 static bool 2531 typeok_plus(op_t op, 2532 const type_t *ltp, tspec_t lt, 2533 const type_t *rtp, tspec_t rt) 2534 { 2535 /* operands have scalar types (checked in typeok) */ 2536 if ((lt == PTR && !is_integer(rt)) || (rt == PTR && !is_integer(lt))) { 2537 warn_incompatible_types(op, ltp, lt, rtp, rt); 2538 return false; 2539 } 2540 return true; 2541 } 2542 2543 static bool 2544 typeok_minus(op_t op, 2545 const type_t *ltp, tspec_t lt, 2546 const type_t *rtp, tspec_t rt) 2547 { 2548 /* operands have scalar types (checked in typeok) */ 2549 if ((lt == PTR && rt != PTR && !is_integer(rt)) || 2550 (lt != PTR && rt == PTR)) { 2551 warn_incompatible_types(op, ltp, lt, rtp, rt); 2552 return false; 2553 } 2554 if (lt == PTR && rt == PTR && 2555 !types_compatible(ltp->t_subt, rtp->t_subt, true, false, NULL)) { 2556 /* invalid pointer subtraction */ 2557 error(116); 2558 } 2559 return true; 2560 } 2561 2562 static void 2563 typeok_shr(op_t op, 2564 const tnode_t *ln, tspec_t lt, 2565 const tnode_t *rn, tspec_t rt) 2566 { 2567 tspec_t olt = before_conversion(ln)->tn_type->t_tspec; 2568 tspec_t ort = before_conversion(rn)->tn_type->t_tspec; 2569 2570 /* operands have integer types (checked in typeok) */ 2571 if (pflag && !is_uinteger(olt)) { 2572 integer_constraints lc = ic_expr(ln); 2573 if (lc.bclr >> 63 != 0) 2574 return; 2575 2576 if (ln->tn_op != CON) 2577 /* bitwise '%s' on signed value possibly nonportable */ 2578 warning(117, op_name(op)); 2579 else if (ln->u.value.u.integer < 0) 2580 /* bitwise '%s' on signed value nonportable */ 2581 warning(120, op_name(op)); 2582 } else if (allow_trad && allow_c90 && 2583 !is_uinteger(olt) && is_uinteger(ort)) { 2584 /* The left operand would become unsigned in traditional C. */ 2585 if (hflag && (ln->tn_op != CON || ln->u.value.u.integer < 0)) { 2586 /* semantics of '%s' change in C90; use ... */ 2587 warning(118, op_name(op)); 2588 } 2589 } else if (allow_trad && allow_c90 && 2590 !is_uinteger(olt) && !is_uinteger(ort) && 2591 portable_rank_cmp(lt, rt) < 0) { 2592 /* 2593 * In traditional C, the left operand would be extended 2594 * (possibly sign-extended) and then shifted. 2595 */ 2596 if (hflag && (ln->tn_op != CON || ln->u.value.u.integer < 0)) { 2597 /* semantics of '%s' change in C90; use ... */ 2598 warning(118, op_name(op)); 2599 } 2600 } 2601 } 2602 2603 static void 2604 typeok_shl(op_t op, tspec_t lt, tspec_t rt) 2605 { 2606 /* 2607 * C90 does not perform balancing for shift operations, but traditional 2608 * C does. If the width of the right operand is greater than the width 2609 * of the left operand, then in traditional C the left operand would be 2610 * extended to the width of the right operand. For SHL this may result 2611 * in different results. 2612 */ 2613 if (portable_rank_cmp(lt, rt) < 0) { 2614 /* 2615 * XXX If both operands are constant, make sure that there is 2616 * really a difference between C90 and traditional C. 2617 */ 2618 if (hflag && allow_trad && allow_c90) 2619 /* semantics of '%s' change in C90; use ... */ 2620 warning(118, op_name(op)); 2621 } 2622 } 2623 2624 static void 2625 typeok_shift(const type_t *ltp, tspec_t lt, const tnode_t *rn, tspec_t rt) 2626 { 2627 if (rn->tn_op != CON) 2628 return; 2629 2630 if (!is_uinteger(rt) && rn->u.value.u.integer < 0) 2631 /* negative shift */ 2632 warning(121); 2633 else if ((uint64_t)rn->u.value.u.integer == size_in_bits(lt)) 2634 /* shift amount %u equals bit-size of '%s' */ 2635 warning(267, (unsigned)rn->u.value.u.integer, type_name(ltp)); 2636 else if ((uint64_t)rn->u.value.u.integer > size_in_bits(lt)) { 2637 /* shift amount %llu is greater than bit-size %llu of '%s' */ 2638 warning(122, (unsigned long long)rn->u.value.u.integer, 2639 (unsigned long long)size_in_bits(lt), 2640 tspec_name(lt)); 2641 } 2642 } 2643 2644 static bool 2645 is_typeok_eq(const tnode_t *ln, tspec_t lt, const tnode_t *rn, tspec_t rt) 2646 { 2647 if (lt == PTR && is_null_pointer(rn)) 2648 return true; 2649 if (rt == PTR && is_null_pointer(ln)) 2650 return true; 2651 return false; 2652 } 2653 2654 static void 2655 warn_incompatible_pointers(op_t op, const type_t *ltp, const type_t *rtp) 2656 { 2657 lint_assert(ltp->t_tspec == PTR); 2658 lint_assert(rtp->t_tspec == PTR); 2659 2660 tspec_t lt = ltp->t_subt->t_tspec; 2661 tspec_t rt = rtp->t_subt->t_tspec; 2662 2663 if (is_struct_or_union(lt) && is_struct_or_union(rt)) { 2664 if (op == RETURN) 2665 /* invalid structure pointer combination */ 2666 warning(244); 2667 else { 2668 /* incompatible structure pointers: '%s' '%s' '%s' */ 2669 warning(245, type_name(ltp), 2670 op_name(op), type_name(rtp)); 2671 } 2672 } else { 2673 if (op == RETURN) 2674 /* invalid combination of '%s' and '%s' */ 2675 warning(184, type_name(ltp), type_name(rtp)); 2676 else { 2677 /* invalid combination of '%s' and '%s', op '%s' */ 2678 warning(124, 2679 type_name(ltp), type_name(rtp), op_name(op)); 2680 } 2681 } 2682 } 2683 2684 static void 2685 check_pointer_comparison(op_t op, const tnode_t *ln, const tnode_t *rn) 2686 { 2687 type_t *ltp = ln->tn_type, *rtp = rn->tn_type; 2688 tspec_t lst = ltp->t_subt->t_tspec, rst = rtp->t_subt->t_tspec; 2689 2690 if (lst == VOID || rst == VOID) { 2691 /* TODO: C99 behaves like C90 here. */ 2692 if (!allow_trad && !allow_c99 && 2693 (lst == FUNC || rst == FUNC)) { 2694 /* (void *)0 is already handled in typeok() */ 2695 const char *lsts, *rsts; 2696 *(lst == FUNC ? &lsts : &rsts) = "function pointer"; 2697 *(lst == VOID ? &lsts : &rsts) = "'void *'"; 2698 /* C90 or later forbid comparison of %s with %s */ 2699 warning(274, lsts, rsts); 2700 } 2701 return; 2702 } 2703 2704 if (!types_compatible(ltp->t_subt, rtp->t_subt, true, false, NULL)) { 2705 warn_incompatible_pointers(op, ltp, rtp); 2706 return; 2707 } 2708 2709 if (lst == FUNC && rst == FUNC) { 2710 /* TODO: C99 behaves like C90 here, see C99 6.5.8p2. */ 2711 if (!allow_trad && !allow_c99 && op != EQ && op != NE) 2712 /* pointers to functions can only be compared ... */ 2713 warning(125); 2714 } 2715 } 2716 2717 static bool 2718 typeok_compare(op_t op, 2719 const tnode_t *ln, const type_t *ltp, tspec_t lt, 2720 const tnode_t *rn, const type_t *rtp, tspec_t rt) 2721 { 2722 if (lt == PTR && rt == PTR) { 2723 check_pointer_comparison(op, ln, rn); 2724 return true; 2725 } 2726 2727 if (lt != PTR && rt != PTR) 2728 return true; 2729 2730 if (!is_integer(lt) && !is_integer(rt)) { 2731 warn_incompatible_types(op, ltp, lt, rtp, rt); 2732 return false; 2733 } 2734 2735 const char *lx = lt == PTR ? "pointer" : "integer"; 2736 const char *rx = rt == PTR ? "pointer" : "integer"; 2737 /* invalid combination of %s '%s' and %s '%s', op '%s' */ 2738 warning(123, lx, type_name(ltp), rx, type_name(rtp), op_name(op)); 2739 return true; 2740 } 2741 2742 static bool 2743 typeok_quest(tspec_t lt, const tnode_t *rn) 2744 { 2745 if (!is_scalar(lt)) { 2746 /* first operand of '?' must have scalar type */ 2747 error(170); 2748 return false; 2749 } 2750 lint_assert(before_conversion(rn)->tn_op == COLON); 2751 return true; 2752 } 2753 2754 static void 2755 typeok_colon_pointer(const type_t *ltp, const type_t *rtp) 2756 { 2757 type_t *lstp = ltp->t_subt; 2758 type_t *rstp = rtp->t_subt; 2759 tspec_t lst = lstp->t_tspec; 2760 tspec_t rst = rstp->t_tspec; 2761 2762 if ((lst == VOID && rst == FUNC) || (lst == FUNC && rst == VOID)) { 2763 /* (void *)0 is handled in typeok_colon */ 2764 /* TODO: C99 behaves like C90 here. */ 2765 if (!allow_trad && !allow_c99) 2766 /* conversion of %s to %s requires a cast, op %s */ 2767 warning(305, "function pointer", "'void *'", 2768 op_name(COLON)); 2769 return; 2770 } 2771 2772 if (pointer_types_are_compatible(lstp, rstp, true)) 2773 return; 2774 if (!types_compatible(lstp, rstp, true, false, NULL)) 2775 warn_incompatible_pointers(COLON, ltp, rtp); 2776 } 2777 2778 static bool 2779 typeok_colon(const tnode_t *ln, const type_t *ltp, tspec_t lt, 2780 const tnode_t *rn, const type_t *rtp, tspec_t rt) 2781 { 2782 2783 if (is_arithmetic(lt) && is_arithmetic(rt)) 2784 return true; 2785 if (lt == BOOL && rt == BOOL) 2786 return true; 2787 2788 if (lt == STRUCT && rt == STRUCT && ltp->u.sou == rtp->u.sou) 2789 return true; 2790 if (lt == UNION && rt == UNION && ltp->u.sou == rtp->u.sou) 2791 return true; 2792 2793 if (lt == PTR && is_null_pointer(rn)) 2794 return true; 2795 if (rt == PTR && is_null_pointer(ln)) 2796 return true; 2797 2798 if ((lt == PTR && is_integer(rt)) || (is_integer(lt) && rt == PTR)) { 2799 const char *lx = lt == PTR ? "pointer" : "integer"; 2800 const char *rx = rt == PTR ? "pointer" : "integer"; 2801 /* invalid combination of %s '%s' and %s '%s', op '%s' */ 2802 warning(123, lx, type_name(ltp), 2803 rx, type_name(rtp), op_name(COLON)); 2804 return true; 2805 } 2806 2807 if (lt == VOID || rt == VOID) { 2808 if (lt != VOID || rt != VOID) 2809 /* incompatible types '%s' and '%s' in conditional */ 2810 warning(126, type_name(ltp), type_name(rtp)); 2811 return true; 2812 } 2813 2814 if (lt == PTR && rt == PTR) { 2815 typeok_colon_pointer(ltp, rtp); 2816 return true; 2817 } 2818 2819 /* incompatible types '%s' and '%s' in conditional */ 2820 error(126, type_name(ltp), type_name(rtp)); 2821 return false; 2822 } 2823 2824 static bool 2825 has_constant_member(const type_t *tp) 2826 { 2827 lint_assert(is_struct_or_union(tp->t_tspec)); 2828 2829 for (sym_t *m = tp->u.sou->sou_first_member; 2830 m != NULL; m = m->s_next) { 2831 const type_t *mtp = m->s_type; 2832 if (mtp->t_const) 2833 return true; 2834 if (is_struct_or_union(mtp->t_tspec) && 2835 has_constant_member(mtp)) 2836 return true; 2837 } 2838 return false; 2839 } 2840 2841 static bool 2842 typeok_assign(op_t op, const tnode_t *ln, const type_t *ltp, tspec_t lt) 2843 { 2844 if (op == RETURN || op == INIT || op == FARG) 2845 return true; 2846 2847 if (!ln->tn_lvalue) { 2848 if (ln->tn_op == CVT && ln->tn_cast && 2849 ln->u.ops.left->tn_op == LOAD) 2850 /* a cast does not yield an lvalue */ 2851 error(163); 2852 /* %soperand of '%s' must be lvalue */ 2853 error(114, "left ", op_name(op)); 2854 return false; 2855 } else if (ltp->t_const 2856 || (is_struct_or_union(lt) && has_constant_member(ltp))) { 2857 if (allow_c90) 2858 /* %soperand of '%s' must be modifiable lvalue */ 2859 warning(115, "left ", op_name(op)); 2860 } 2861 return true; 2862 } 2863 2864 static bool 2865 typeok_scalar(op_t op, const mod_t *mp, 2866 const type_t *ltp, tspec_t lt, 2867 const type_t *rtp, tspec_t rt) 2868 { 2869 if (mp->m_takes_bool && lt == BOOL && rt == BOOL) 2870 return true; 2871 if (mp->m_requires_integer) { 2872 if (!is_integer(lt) || (mp->m_binary && !is_integer(rt))) { 2873 warn_incompatible_types(op, ltp, lt, rtp, rt); 2874 return false; 2875 } 2876 } else if (mp->m_requires_integer_or_complex) { 2877 if ((!is_integer(lt) && !is_complex(lt)) || 2878 (mp->m_binary && (!is_integer(rt) && !is_complex(rt)))) { 2879 warn_incompatible_types(op, ltp, lt, rtp, rt); 2880 return false; 2881 } 2882 } else if (mp->m_requires_scalar) { 2883 if (!is_scalar(lt) || (mp->m_binary && !is_scalar(rt))) { 2884 warn_incompatible_types(op, ltp, lt, rtp, rt); 2885 return false; 2886 } 2887 } else if (mp->m_requires_arith) { 2888 if (!is_arithmetic(lt) || 2889 (mp->m_binary && !is_arithmetic(rt))) { 2890 warn_incompatible_types(op, ltp, lt, rtp, rt); 2891 return false; 2892 } 2893 } 2894 return true; 2895 } 2896 2897 static void 2898 check_assign_void_pointer(op_t op, int arg, 2899 tspec_t lt, tspec_t lst, 2900 tspec_t rt, tspec_t rst) 2901 { 2902 2903 if (!(lt == PTR && rt == PTR && (lst == VOID || rst == VOID))) 2904 return; 2905 /* two pointers, at least one pointer to void */ 2906 2907 /* TODO: C99 behaves like C90 here. */ 2908 if (!(!allow_trad && !allow_c99 && (lst == FUNC || rst == FUNC))) 2909 return; 2910 /* comb. of ptr to func and ptr to void */ 2911 2912 const char *lts, *rts; 2913 *(lst == FUNC ? <s : &rts) = "function pointer"; 2914 *(lst == VOID ? <s : &rts) = "'void *'"; 2915 2916 switch (op) { 2917 case INIT: 2918 case RETURN: 2919 /* conversion of %s to %s requires a cast */ 2920 warning(303, rts, lts); 2921 break; 2922 case FARG: 2923 /* conversion of %s to %s requires a cast, arg #%d */ 2924 warning(304, rts, lts, arg); 2925 break; 2926 default: 2927 /* conversion of %s to %s requires a cast, op %s */ 2928 warning(305, rts, lts, op_name(op)); 2929 break; 2930 } 2931 } 2932 2933 static bool 2934 is_direct_function_call(const tnode_t *tn, const char **out_name) 2935 { 2936 2937 if (tn->tn_op == CALL 2938 && tn->u.call->func->tn_op == ADDR 2939 && tn->u.call->func->u.ops.left->tn_op == NAME) { 2940 *out_name = tn->u.call->func->u.ops.left->u.sym->s_name; 2941 return true; 2942 } 2943 return false; 2944 } 2945 2946 static bool 2947 is_unconst_function(const char *name) 2948 { 2949 2950 return strcmp(name, "memchr") == 0 || 2951 strcmp(name, "strchr") == 0 || 2952 strcmp(name, "strpbrk") == 0 || 2953 strcmp(name, "strrchr") == 0 || 2954 strcmp(name, "strstr") == 0; 2955 } 2956 2957 static bool 2958 is_const_char_pointer(const tnode_t *tn) 2959 { 2960 /* 2961 * For traditional reasons, C99 6.4.5p5 defines that string literals 2962 * have type 'char[]'. They are often implicitly converted to 'char 2963 * *', for example when they are passed as function arguments. 2964 * 2965 * C99 6.4.5p6 further defines that modifying a string that is 2966 * constructed from a string literal invokes undefined behavior. 2967 * 2968 * Out of these reasons, string literals are treated as 'effectively 2969 * const' here. 2970 */ 2971 if (tn->tn_op == CVT && 2972 tn->u.ops.left->tn_op == ADDR && 2973 tn->u.ops.left->u.ops.left->tn_op == STRING) 2974 return true; 2975 2976 const type_t *tp = before_conversion(tn)->tn_type; 2977 return tp->t_tspec == PTR && 2978 tp->t_subt->t_tspec == CHAR && 2979 tp->t_subt->t_const; 2980 } 2981 2982 static bool 2983 is_const_pointer(const tnode_t *tn) 2984 { 2985 const type_t *tp = before_conversion(tn)->tn_type; 2986 return tp->t_tspec == PTR && tp->t_subt->t_const; 2987 } 2988 2989 static void 2990 check_unconst_function(const type_t *lstp, const tnode_t *rn) 2991 { 2992 const char *function_name; 2993 2994 if (lstp->t_tspec == CHAR && !lstp->t_const && 2995 is_direct_function_call(rn, &function_name) && 2996 is_unconst_function(function_name) && 2997 rn->u.call->args_len >= 1 && 2998 is_const_char_pointer(rn->u.call->args[0])) { 2999 /* call to '%s' effectively discards 'const' from argument */ 3000 warning(346, function_name); 3001 } 3002 3003 if (!lstp->t_const && 3004 is_direct_function_call(rn, &function_name) && 3005 strcmp(function_name, "bsearch") == 0 && 3006 rn->u.call->args_len >= 2 && 3007 is_const_pointer(rn->u.call->args[1])) { 3008 /* call to '%s' effectively discards 'const' from argument */ 3009 warning(346, function_name); 3010 } 3011 } 3012 3013 static bool 3014 check_assign_void_pointer_compat(op_t op, const function_call *call, int arg, 3015 tspec_t lt, 3016 const type_t *lstp, tspec_t lst, 3017 const tnode_t *rn, 3018 const type_t *rtp, tspec_t rt, 3019 const type_t *rstp, tspec_t rst) 3020 { 3021 if (!(lt == PTR && rt == PTR && (lst == VOID || rst == VOID || 3022 types_compatible(lstp, rstp, 3023 true, false, NULL)))) 3024 return false; 3025 3026 /* compatible pointer types (qualifiers ignored) */ 3027 char qualifiers[32]; 3028 snprintf(qualifiers, sizeof(qualifiers), "%s%s", 3029 !lstp->t_const && rstp->t_const ? " const" : "", 3030 !lstp->t_volatile && rstp->t_volatile ? " volatile" : ""); 3031 if (allow_c90 && qualifiers[0] != '\0') { 3032 switch (op) { 3033 case INIT: 3034 case RETURN: 3035 /* '%s' discards '%s' from '%s' */ 3036 warning(182, op_name(op), 3037 qualifiers + 1, type_name(rtp)); 3038 break; 3039 case FARG: 3040 /* passing '%s' as argument %d to '%s' discards '%s' */ 3041 warning(383, type_name(rtp), arg, 3042 function_call_descr(call), qualifiers + 1); 3043 break; 3044 default: 3045 /* operator '%s' discards '%s' from '%s' */ 3046 warning(128, op_name(op), 3047 qualifiers + 1, type_name(rtp)); 3048 break; 3049 } 3050 } 3051 3052 if (allow_c90) 3053 check_unconst_function(lstp, rn); 3054 3055 return true; 3056 } 3057 3058 static bool 3059 check_assign_pointer_integer(op_t op, int arg, 3060 const type_t *ltp, tspec_t lt, 3061 const type_t *rtp, tspec_t rt) 3062 { 3063 3064 if (!((lt == PTR && is_integer(rt)) || (is_integer(lt) && rt == PTR))) 3065 return false; 3066 3067 const char *lx = lt == PTR ? "pointer" : "integer"; 3068 const char *rx = rt == PTR ? "pointer" : "integer"; 3069 3070 switch (op) { 3071 case INIT: 3072 case RETURN: 3073 /* invalid combination of %s '%s' and %s '%s' for '%s' */ 3074 warning(183, 3075 lx, type_name(ltp), rx, type_name(rtp), op_name(op)); 3076 break; 3077 case FARG: 3078 /* invalid combination of %s '%s' and %s '%s', arg #%d */ 3079 warning(154, 3080 lx, type_name(ltp), rx, type_name(rtp), arg); 3081 break; 3082 default: 3083 /* invalid combination of %s '%s' and %s '%s', op '%s' */ 3084 warning(123, 3085 lx, type_name(ltp), rx, type_name(rtp), op_name(op)); 3086 break; 3087 } 3088 return true; 3089 } 3090 3091 static bool 3092 check_assign_pointer(op_t op, int arg, 3093 const type_t *ltp, tspec_t lt, 3094 const type_t *rtp, tspec_t rt) 3095 { 3096 if (!(lt == PTR && rt == PTR)) 3097 return false; 3098 3099 if (op == FARG) 3100 /* converting '%s' to incompatible '%s' for ... */ 3101 warning(153, type_name(rtp), type_name(ltp), arg); 3102 else 3103 warn_incompatible_pointers(op, ltp, rtp); 3104 return true; 3105 } 3106 3107 static void 3108 warn_assign(op_t op, int arg, 3109 const type_t *ltp, tspec_t lt, 3110 const type_t *rtp, tspec_t rt) 3111 { 3112 switch (op) { 3113 case INIT: 3114 /* cannot initialize '%s' from '%s' */ 3115 error(185, type_name(ltp), type_name(rtp)); 3116 break; 3117 case RETURN: 3118 /* function has return type '%s' but returns '%s' */ 3119 error(211, type_name(ltp), type_name(rtp)); 3120 break; 3121 case FARG: 3122 /* passing '%s' to incompatible '%s', arg #%d */ 3123 warning(155, type_name(rtp), type_name(ltp), arg); 3124 break; 3125 default: 3126 warn_incompatible_types(op, ltp, lt, rtp, rt); 3127 break; 3128 } 3129 } 3130 3131 /* 3132 * Checks type compatibility for ASSIGN, INIT, FARG and RETURN 3133 * and prints warnings/errors if necessary. 3134 * Returns whether the types are (almost) compatible. 3135 */ 3136 static bool 3137 check_assign_types_compatible(op_t op, const function_call *call, int arg, 3138 const tnode_t *ln, const tnode_t *rn) 3139 { 3140 tspec_t lt, rt, lst = NO_TSPEC, rst = NO_TSPEC; 3141 type_t *ltp, *rtp, *lstp = NULL, *rstp = NULL; 3142 3143 if ((lt = (ltp = ln->tn_type)->t_tspec) == PTR) 3144 lst = (lstp = ltp->t_subt)->t_tspec; 3145 if ((rt = (rtp = rn->tn_type)->t_tspec) == PTR) 3146 rst = (rstp = rtp->t_subt)->t_tspec; 3147 3148 if (lt == BOOL && is_scalar(rt)) /* C99 6.3.1.2 */ 3149 return true; 3150 3151 if (is_arithmetic(lt) && (is_arithmetic(rt) || rt == BOOL)) 3152 return true; 3153 3154 if (is_struct_or_union(lt) && is_struct_or_union(rt)) 3155 return ltp->u.sou == rtp->u.sou; 3156 3157 if (lt == PTR && is_null_pointer(rn)) { 3158 if (is_integer(rn->tn_type->t_tspec)) 3159 /* implicit conversion from integer 0 to pointer ... */ 3160 query_message(15, type_name(ltp)); 3161 return true; 3162 } 3163 3164 check_assign_void_pointer(op, arg, lt, lst, rt, rst); 3165 3166 if (check_assign_void_pointer_compat(op, call, arg, 3167 lt, lstp, lst, rn, rtp, rt, rstp, rst)) 3168 return true; 3169 3170 if (check_assign_pointer_integer(op, arg, ltp, lt, rtp, rt)) 3171 return true; 3172 3173 if (check_assign_pointer(op, arg, ltp, lt, rtp, rt)) 3174 return true; 3175 3176 warn_assign(op, arg, ltp, lt, rtp, rt); 3177 return false; 3178 } 3179 3180 static bool 3181 has_side_effect(const tnode_t *tn) /* NOLINT(misc-no-recursion) */ 3182 { 3183 op_t op = tn->tn_op; 3184 3185 if (modtab[op].m_has_side_effect) 3186 return true; 3187 3188 if (op == CVT && tn->tn_type->t_tspec == VOID) 3189 return has_side_effect(tn->u.ops.left); 3190 3191 /* XXX: Why not has_side_effect(tn->u.ops.left) as well? */ 3192 if (op == LOGAND || op == LOGOR) 3193 return has_side_effect(tn->u.ops.right); 3194 3195 /* XXX: Why not has_side_effect(tn->u.ops.left) as well? */ 3196 if (op == QUEST) 3197 return has_side_effect(tn->u.ops.right); 3198 3199 if (op == COLON || op == COMMA) { 3200 return has_side_effect(tn->u.ops.left) || 3201 has_side_effect(tn->u.ops.right); 3202 } 3203 3204 return false; 3205 } 3206 3207 static bool 3208 is_void_cast(const tnode_t *tn) 3209 { 3210 3211 return tn->tn_op == CVT && tn->tn_cast && 3212 tn->tn_type->t_tspec == VOID; 3213 } 3214 3215 static bool 3216 is_local_symbol(const tnode_t *tn) 3217 { 3218 3219 return tn->tn_op == LOAD && 3220 tn->u.ops.left->tn_op == NAME && 3221 tn->u.ops.left->u.sym->s_scl == AUTO; 3222 } 3223 3224 static bool 3225 is_int_constant_zero(const tnode_t *tn) 3226 { 3227 3228 return tn->tn_op == CON && 3229 tn->tn_type->t_tspec == INT && 3230 tn->u.value.u.integer == 0; 3231 } 3232 3233 static void 3234 check_null_effect(const tnode_t *tn) 3235 { 3236 3237 if (hflag && 3238 !has_side_effect(tn) && 3239 !(is_void_cast(tn) && is_local_symbol(tn->u.ops.left)) && 3240 !(is_void_cast(tn) && is_int_constant_zero(tn->u.ops.left))) { 3241 /* expression has null effect */ 3242 warning(129); 3243 } 3244 } 3245 3246 /* 3247 * Check the types for specific operators and type combinations. 3248 * 3249 * At this point, the operands already conform to the type requirements of 3250 * the operator, such as being integer, floating or scalar. 3251 */ 3252 static bool 3253 typeok_op(op_t op, const function_call *call, int arg, 3254 const tnode_t *ln, const type_t *ltp, tspec_t lt, 3255 const tnode_t *rn, const type_t *rtp, tspec_t rt) 3256 { 3257 switch (op) { 3258 case ARROW: 3259 return typeok_arrow(lt); 3260 case POINT: 3261 return typeok_point(ln, ltp, lt); 3262 case INCBEF: 3263 case DECBEF: 3264 case INCAFT: 3265 case DECAFT: 3266 return typeok_incdec(op, ln, ltp); 3267 case INDIR: 3268 return typeok_indir(ltp, lt); 3269 case ADDR: 3270 return typeok_address(op, ln, ltp, lt); 3271 case PLUS: 3272 return typeok_plus(op, ltp, lt, rtp, rt); 3273 case MINUS: 3274 return typeok_minus(op, ltp, lt, rtp, rt); 3275 case SHL: 3276 typeok_shl(op, lt, rt); 3277 goto shift; 3278 case SHR: 3279 typeok_shr(op, ln, lt, rn, rt); 3280 shift: 3281 typeok_shift(ltp, lt, rn, rt); 3282 break; 3283 case LT: 3284 case LE: 3285 case GT: 3286 case GE: 3287 compare: 3288 return typeok_compare(op, ln, ltp, lt, rn, rtp, rt); 3289 case EQ: 3290 case NE: 3291 if (is_typeok_eq(ln, lt, rn, rt)) 3292 break; 3293 goto compare; 3294 case QUEST: 3295 return typeok_quest(lt, rn); 3296 case COLON: 3297 return typeok_colon(ln, ltp, lt, rn, rtp, rt); 3298 case ASSIGN: 3299 case INIT: 3300 case FARG: 3301 case RETURN: 3302 if (!check_assign_types_compatible(op, call, arg, ln, rn)) 3303 return false; 3304 goto assign; 3305 case MULASS: 3306 case DIVASS: 3307 case MODASS: 3308 goto assign; 3309 case ADDASS: 3310 case SUBASS: 3311 if ((lt == PTR && !is_integer(rt)) || rt == PTR) { 3312 warn_incompatible_types(op, ltp, lt, rtp, rt); 3313 return false; 3314 } 3315 goto assign; 3316 case SHLASS: 3317 goto assign; 3318 case SHRASS: 3319 if (pflag && !is_uinteger(lt) && 3320 !(!allow_c90 && is_uinteger(rt))) { 3321 /* bitwise '%s' on signed value possibly nonportable */ 3322 warning(117, op_name(op)); 3323 } 3324 goto assign; 3325 case ANDASS: 3326 case XORASS: 3327 case ORASS: 3328 assign: 3329 return typeok_assign(op, ln, ltp, lt); 3330 case COMMA: 3331 if (!modtab[ln->tn_op].m_has_side_effect) 3332 check_null_effect(ln); 3333 break; 3334 default: 3335 break; 3336 } 3337 return true; 3338 } 3339 3340 static void 3341 check_bad_enum_operation(op_t op, const tnode_t *ln, const tnode_t *rn) 3342 { 3343 3344 if (!eflag) 3345 return; 3346 3347 /* Allow enum in array indices. */ 3348 if (op == PLUS && 3349 ((ln->tn_type->t_is_enum && rn->tn_type->t_tspec == PTR) || 3350 (rn->tn_type->t_is_enum && ln->tn_type->t_tspec == PTR))) { 3351 return; 3352 } 3353 3354 /* dubious operation '%s' on enum */ 3355 warning(241, op_name(op)); 3356 } 3357 3358 static void 3359 check_enum_type_mismatch(op_t op, int arg, const tnode_t *ln, const tnode_t *rn) 3360 { 3361 const mod_t *mp = &modtab[op]; 3362 3363 if (ln->tn_type->u.enumer != rn->tn_type->u.enumer) { 3364 switch (op) { 3365 case INIT: 3366 /* enum type mismatch between '%s' and '%s' in ... */ 3367 warning(210, 3368 type_name(ln->tn_type), type_name(rn->tn_type)); 3369 break; 3370 case FARG: 3371 /* function expects '%s', passing '%s' for arg #%d */ 3372 warning(156, 3373 type_name(ln->tn_type), type_name(rn->tn_type), 3374 arg); 3375 break; 3376 case RETURN: 3377 /* function has return type '%s' but returns '%s' */ 3378 warning(211, 3379 type_name(ln->tn_type), type_name(rn->tn_type)); 3380 break; 3381 default: 3382 /* enum type mismatch: '%s' '%s' '%s' */ 3383 warning(130, type_name(ln->tn_type), op_name(op), 3384 type_name(rn->tn_type)); 3385 break; 3386 } 3387 } else if (Pflag && eflag && mp->m_comparison && op != EQ && op != NE) 3388 /* operator '%s' assumes that '%s' is ordered */ 3389 warning(243, op_name(op), type_name(ln->tn_type)); 3390 } 3391 3392 static void 3393 check_enum_int_mismatch(op_t op, int arg, const tnode_t *ln, const tnode_t *rn) 3394 { 3395 3396 if (!eflag) 3397 return; 3398 3399 switch (op) { 3400 case INIT: 3401 /* 3402 * Initialization with 0 is allowed. Otherwise, all implicit 3403 * initializations would need to be warned upon as well. 3404 */ 3405 if (!rn->tn_type->t_is_enum && rn->tn_op == CON && 3406 is_integer(rn->tn_type->t_tspec) && 3407 rn->u.value.u.integer == 0) { 3408 return; 3409 } 3410 /* initialization of '%s' with '%s' */ 3411 warning(277, type_name(ln->tn_type), type_name(rn->tn_type)); 3412 break; 3413 case FARG: 3414 /* combination of '%s' and '%s', arg #%d */ 3415 warning(278, 3416 type_name(ln->tn_type), type_name(rn->tn_type), arg); 3417 break; 3418 case RETURN: 3419 /* combination of '%s' and '%s' in return */ 3420 warning(279, type_name(ln->tn_type), type_name(rn->tn_type)); 3421 break; 3422 default: 3423 /* combination of '%s' and '%s', op '%s' */ 3424 warning(242, type_name(ln->tn_type), type_name(rn->tn_type), 3425 op_name(op)); 3426 break; 3427 } 3428 } 3429 3430 static void 3431 typeok_enum(op_t op, const mod_t *mp, int arg, 3432 const tnode_t *ln, const type_t *ltp, 3433 const tnode_t *rn, const type_t *rtp) 3434 { 3435 if (mp->m_bad_on_enum && 3436 (ltp->t_is_enum || (mp->m_binary && rtp->t_is_enum))) { 3437 check_bad_enum_operation(op, ln, rn); 3438 } else if (mp->m_valid_on_enum && 3439 (ltp->t_is_enum && rtp != NULL && rtp->t_is_enum)) { 3440 check_enum_type_mismatch(op, arg, ln, rn); 3441 } else if (mp->m_valid_on_enum && 3442 (ltp->t_is_enum || (rtp != NULL && rtp->t_is_enum))) { 3443 check_enum_int_mismatch(op, arg, ln, rn); 3444 } 3445 } 3446 3447 /* Perform most type checks. Return whether the types are ok. */ 3448 bool 3449 typeok(op_t op, const function_call *call, int arg, 3450 const tnode_t *ln, const tnode_t *rn) 3451 { 3452 3453 const mod_t *mp = &modtab[op]; 3454 3455 type_t *ltp = ln->tn_type; 3456 tspec_t lt = ltp->t_tspec; 3457 3458 type_t *rtp = mp->m_binary ? rn->tn_type : NULL; 3459 tspec_t rt = mp->m_binary ? rtp->t_tspec : NO_TSPEC; 3460 3461 if (Tflag && !typeok_scalar_strict_bool(op, mp, arg, ln, rn)) 3462 return false; 3463 if (!typeok_scalar(op, mp, ltp, lt, rtp, rt)) 3464 return false; 3465 3466 if (!typeok_op(op, call, arg, ln, ltp, lt, rn, rtp, rt)) 3467 return false; 3468 3469 typeok_enum(op, mp, arg, ln, ltp, rn, rtp); 3470 return true; 3471 } 3472 3473 /* In traditional C, keep unsigned and promote FLOAT to DOUBLE. */ 3474 static tspec_t 3475 promote_trad(tspec_t t) 3476 { 3477 3478 if (t == UCHAR || t == USHORT) 3479 return UINT; 3480 if (t == CHAR || t == SCHAR || t == SHORT) 3481 return INT; 3482 if (t == FLOAT) 3483 return DOUBLE; 3484 if (t == ENUM) 3485 return INT; 3486 return t; 3487 } 3488 3489 /* 3490 * C99 6.3.1.1p2 requires for types with lower rank than int that "If an int 3491 * can represent all the values of the original type, the value is converted 3492 * to an int; otherwise it is converted to an unsigned int", and that "All 3493 * other types are unchanged by the integer promotions". 3494 */ 3495 static tspec_t 3496 promote_c90(const tnode_t *tn, tspec_t t, bool farg) 3497 { 3498 if (tn->tn_type->t_bitfield) { 3499 unsigned int width = tn->tn_type->t_bit_field_width; 3500 unsigned int int_width = size_in_bits(INT); 3501 // XXX: What about _Bool bit-fields, since C99? 3502 if (width < int_width) 3503 return INT; 3504 if (width == int_width) 3505 return is_uinteger(t) ? UINT : INT; 3506 return t; 3507 } 3508 3509 if (t == CHAR || t == SCHAR) 3510 return INT; 3511 if (t == UCHAR) 3512 return size_in_bits(CHAR) < size_in_bits(INT) ? INT : UINT; 3513 if (t == SHORT) 3514 return INT; 3515 if (t == USHORT) 3516 return size_in_bits(SHORT) < size_in_bits(INT) ? INT : UINT; 3517 if (t == ENUM) 3518 return INT; 3519 if (farg && t == FLOAT) 3520 return DOUBLE; 3521 return t; 3522 } 3523 3524 /* 3525 * Performs the "integer promotions" (C99 6.3.1.1p2), which convert small 3526 * integer types to either int or unsigned int. 3527 * 3528 * If allow_c90 is unset or the operand is a function argument with no type 3529 * information (no prototype or variable # of args), converts float to double. 3530 */ 3531 tnode_t * 3532 promote(op_t op, bool farg, tnode_t *tn) 3533 { 3534 3535 const type_t *otp = tn->tn_type; 3536 tspec_t ot = otp->t_tspec; 3537 if (!is_arithmetic(ot)) 3538 return tn; 3539 3540 tspec_t nt = allow_c90 ? promote_c90(tn, ot, farg) : promote_trad(ot); 3541 if (nt == ot) 3542 return tn; 3543 3544 type_t *ntp = expr_dup_type(gettyp(nt)); 3545 ntp->t_tspec = nt; 3546 ntp->t_is_enum = otp->t_is_enum; 3547 if (ntp->t_is_enum) 3548 ntp->u.enumer = otp->u.enumer; 3549 ntp->t_bitfield = otp->t_bitfield; 3550 if (ntp->t_bitfield) { 3551 ntp->t_bit_field_width = otp->t_bit_field_width; 3552 ntp->t_bit_field_offset = otp->t_bit_field_offset; 3553 } 3554 if (ntp->t_bitfield && is_uinteger(ot) && !is_uinteger(nt)) 3555 ntp->t_bit_field_width++; 3556 return convert(op, 0, ntp, tn); 3557 } 3558 3559 static void 3560 check_lossy_floating_to_integer_conversion( 3561 op_t op, int arg, const type_t *tp, const tnode_t *tn) 3562 { 3563 long double x = tn->u.value.u.floating; 3564 integer_constraints ic = ic_any(tp); 3565 if (is_uinteger(tp->t_tspec) 3566 ? x >= ic.umin && x <= ic.umax && x == (uint64_t)x 3567 : x >= ic.smin && x <= ic.smax && x == (int64_t)x) 3568 return; 3569 if (op == FARG) 3570 /* lossy conversion of %Lg to '%s', arg #%d */ 3571 warning(380, x, type_name(tp), arg); 3572 else 3573 /* lossy conversion of %Lg to '%s' */ 3574 warning(381, x, type_name(tp)); 3575 } 3576 3577 static void 3578 convert_integer_from_floating( 3579 op_t op, int arg, const type_t *tp, const tnode_t *tn) 3580 { 3581 3582 if (op == CVT) 3583 /* cast from floating point '%s' to integer '%s' */ 3584 query_message(2, type_name(tn->tn_type), type_name(tp)); 3585 else 3586 /* implicit conversion from floating point '%s' to ... */ 3587 query_message(1, type_name(tn->tn_type), type_name(tp)); 3588 if (tn->tn_op == CON) 3589 check_lossy_floating_to_integer_conversion(op, arg, tp, tn); 3590 } 3591 3592 static bool 3593 should_warn_about_prototype_conversion(tspec_t nt, 3594 tspec_t ot, const tnode_t *ptn) 3595 { 3596 3597 if (nt == ot) 3598 return false; 3599 3600 if (nt == ENUM && ot == INT) 3601 return false; 3602 3603 if (is_floating(nt) != is_floating(ot) || 3604 portable_rank_cmp(nt, ot) != 0) { 3605 /* representation and/or width change */ 3606 if (!is_integer(ot)) 3607 return true; 3608 /* 3609 * XXX: Investigate whether this rule makes sense; see 3610 * tests/usr.bin/xlint/lint1/platform_long.c. 3611 */ 3612 return portable_rank_cmp(ot, INT) > 0; 3613 } 3614 3615 if (!hflag) 3616 return false; 3617 3618 /* 3619 * If the types differ only in sign and the argument has the same 3620 * representation in both types, print no warning. 3621 */ 3622 if (ptn->tn_op == CON && is_integer(nt) && 3623 signed_type(nt) == signed_type(ot) && 3624 !msb(ptn->u.value.u.integer, ot)) 3625 return false; 3626 3627 return true; 3628 } 3629 3630 /* 3631 * Warn if a prototype causes a type conversion that is different from what 3632 * would happen to the same argument in the absence of a prototype. This 3633 * check is intended for code that needs to stay compatible with pre-C90 C. 3634 * 3635 * Errors/warnings about invalid type combinations are already printed 3636 * in check_assign_types_compatible(). 3637 */ 3638 static void 3639 check_prototype_conversion(int arg, tspec_t nt, tspec_t ot, type_t *tp, 3640 tnode_t *tn) 3641 { 3642 3643 if (!is_arithmetic(nt) || !is_arithmetic(ot)) 3644 return; 3645 3646 /* 3647 * If the type of the formal parameter is char/short, a warning would 3648 * be useless, because functions declared the old style can't expect 3649 * char/short arguments. 3650 */ 3651 if (nt == CHAR || nt == SCHAR || nt == UCHAR || 3652 nt == SHORT || nt == USHORT) 3653 return; 3654 3655 tnode_t *ptn = promote(NOOP, true, tn); 3656 ot = ptn->tn_type->t_tspec; 3657 3658 if (should_warn_about_prototype_conversion(nt, ot, ptn)) { 3659 /* argument %d is converted from '%s' to '%s' ... */ 3660 warning(259, arg, type_name(tn->tn_type), type_name(tp)); 3661 } 3662 } 3663 3664 /* 3665 * When converting a large integer type to a small integer type, in some 3666 * cases the value of the actual expression is further restricted than the 3667 * type bounds, such as in (expr & 0xFF) or (expr % 100) or (expr >> 24). 3668 */ 3669 static bool 3670 can_represent(const type_t *tp, const tnode_t *tn) 3671 { 3672 uint64_t nmask = value_bits(width_in_bits(tp)); 3673 if (!is_uinteger(tp->t_tspec)) 3674 nmask >>= 1; 3675 3676 integer_constraints c = ic_expr(tn); 3677 if ((~c.bclr & ~nmask) == 0) 3678 return true; 3679 3680 integer_constraints tpc = ic_any(tp); 3681 if (is_uinteger(tp->t_tspec) 3682 ? tpc.umin <= c.umin && tpc.umax >= c.umax 3683 : tpc.smin <= c.smin && tpc.smax >= c.smax) 3684 return true; 3685 3686 debug_enter(); 3687 debug_step("type '%s' cannot represent:", type_name(tp)); 3688 debug_node(tn); 3689 debug_leave(); 3690 return false; 3691 } 3692 3693 static bool 3694 should_warn_about_integer_conversion(const type_t *ntp, tspec_t nt, 3695 const tnode_t *otn, tspec_t ot) 3696 { 3697 3698 // XXX: The portable_rank_cmp aims at portable mode, independent of the 3699 // current platform, while can_represent acts on the actual type sizes 3700 // from the current platform. This mix is inconsistent, but anything 3701 // else would make the exact conditions too complicated to grasp. 3702 if (aflag > 0 && portable_rank_cmp(nt, ot) < 0) { 3703 if (ot == LONG || ot == ULONG 3704 || ot == LLONG || ot == ULLONG 3705 #ifdef INT128_SIZE 3706 || ot == INT128 || ot == UINT128 3707 #endif 3708 || aflag > 1) 3709 return !can_represent(ntp, otn); 3710 } 3711 return false; 3712 } 3713 3714 static void 3715 convert_integer_from_integer(op_t op, int arg, tspec_t nt, tspec_t ot, 3716 type_t *tp, tnode_t *tn) 3717 { 3718 3719 if (tn->tn_op == CON) 3720 return; 3721 3722 if (op == CVT) 3723 return; 3724 3725 if (Pflag && pflag && aflag > 0 && 3726 portable_rank_cmp(nt, ot) > 0 && 3727 is_uinteger(nt) != is_uinteger(ot)) { 3728 if (op == FARG) 3729 /* conversion to '%s' may sign-extend ... */ 3730 warning(297, type_name(tp), arg); 3731 else 3732 /* conversion to '%s' may sign-extend ... */ 3733 warning(131, type_name(tp)); 3734 } 3735 3736 if (Pflag && portable_rank_cmp(nt, ot) > 0 && 3737 (tn->tn_op == PLUS || tn->tn_op == MINUS || tn->tn_op == MULT || 3738 tn->tn_op == SHL)) { 3739 /* suggest cast from '%s' to '%s' on op '%s' to ... */ 3740 warning(324, type_name(gettyp(ot)), type_name(tp), 3741 op_name(tn->tn_op)); 3742 } 3743 3744 if (should_warn_about_integer_conversion(tp, nt, tn, ot)) { 3745 if (op == FARG) { 3746 /* conversion from '%s' to '%s' may lose ... */ 3747 warning(298, 3748 type_name(tn->tn_type), type_name(tp), arg); 3749 } else { 3750 /* conversion from '%s' to '%s' may lose accuracy */ 3751 warning(132, 3752 type_name(tn->tn_type), type_name(tp)); 3753 } 3754 } 3755 3756 if (is_uinteger(nt) != is_uinteger(ot)) 3757 /* implicit conversion changes sign from '%s' to '%s' */ 3758 query_message(3, type_name(tn->tn_type), type_name(tp)); 3759 } 3760 3761 static void 3762 convert_integer_from_pointer(op_t op, tspec_t nt, type_t *tp, tnode_t *tn) 3763 { 3764 3765 if (tn->tn_op == CON) 3766 return; 3767 if (op != CVT) 3768 return; /* We already got an error. */ 3769 if (portable_rank_cmp(nt, PTR) >= 0) 3770 return; 3771 3772 if (pflag && size_in_bits(nt) >= size_in_bits(PTR)) { 3773 /* conversion of pointer to '%s' may lose bits */ 3774 warning(134, type_name(tp)); 3775 } else { 3776 /* conversion of pointer to '%s' loses bits */ 3777 warning(133, type_name(tp)); 3778 } 3779 } 3780 3781 static bool 3782 struct_starts_with(const type_t *struct_tp, const type_t *member_tp) 3783 { 3784 3785 return struct_tp->u.sou->sou_first_member != NULL && 3786 types_compatible(struct_tp->u.sou->sou_first_member->s_type, 3787 member_tp, true, false, NULL); 3788 } 3789 3790 static bool 3791 is_byte_array(const type_t *tp) 3792 { 3793 3794 return tp->t_tspec == ARRAY && 3795 (tp->t_subt->t_tspec == CHAR || tp->t_subt->t_tspec == UCHAR); 3796 } 3797 3798 static bool 3799 union_contains(const type_t *utp, const type_t *mtp) 3800 { 3801 for (const sym_t *mem = utp->u.sou->sou_first_member; 3802 mem != NULL; mem = mem->s_next) { 3803 if (types_compatible(mem->s_type, mtp, true, false, NULL)) 3804 return true; 3805 } 3806 return false; 3807 } 3808 3809 static bool 3810 should_warn_about_pointer_cast(const type_t *nstp, tspec_t nst, 3811 const type_t *ostp, tspec_t ost) 3812 { 3813 3814 while (nst == ARRAY) 3815 nstp = nstp->t_subt, nst = nstp->t_tspec; 3816 while (ost == ARRAY) 3817 ostp = ostp->t_subt, ost = ostp->t_tspec; 3818 3819 if (nst == STRUCT && ost == STRUCT && 3820 (struct_starts_with(nstp, ostp) || 3821 struct_starts_with(ostp, nstp))) 3822 return false; 3823 3824 if (is_incomplete(nstp) || is_incomplete(ostp)) 3825 return false; 3826 3827 if (nst == CHAR || nst == UCHAR) 3828 return false; /* for the sake of traditional C code */ 3829 if (ost == CHAR || ost == UCHAR) 3830 return false; /* for the sake of traditional C code */ 3831 3832 /* Allow cast between pointers to sockaddr variants. */ 3833 if (nst == STRUCT && ost == STRUCT) { 3834 const sym_t *nmem = nstp->u.sou->sou_first_member; 3835 const sym_t *omem = ostp->u.sou->sou_first_member; 3836 while (nmem != NULL && omem != NULL && 3837 types_compatible(nmem->s_type, omem->s_type, 3838 true, false, NULL)) 3839 nmem = nmem->s_next, omem = omem->s_next; 3840 if (nmem != NULL && is_byte_array(nmem->s_type)) 3841 return false; 3842 if (omem != NULL && is_byte_array(omem->s_type)) 3843 return false; 3844 if (nmem == NULL && omem == NULL) 3845 return false; 3846 } 3847 3848 if (nst == UNION || ost == UNION) { 3849 const type_t *union_tp = nst == UNION ? nstp : ostp; 3850 const type_t *other_tp = nst == UNION ? ostp : nstp; 3851 if (union_contains(union_tp, other_tp)) 3852 return false; 3853 } 3854 3855 if (is_struct_or_union(nst) && is_struct_or_union(ost)) 3856 return nstp->u.sou != ostp->u.sou; 3857 3858 enum rank_kind rk1 = type_properties(nst)->tt_rank_kind; 3859 enum rank_kind rk2 = type_properties(ost)->tt_rank_kind; 3860 if (rk1 != rk2 || rk1 == RK_NONE) 3861 return true; 3862 3863 return portable_rank_cmp(nst, ost) != 0; 3864 } 3865 3866 static void 3867 convert_pointer_from_pointer(type_t *ntp, tnode_t *tn) 3868 { 3869 const type_t *nstp = ntp->t_subt; 3870 const type_t *otp = tn->tn_type; 3871 const type_t *ostp = otp->t_subt; 3872 tspec_t nst = nstp->t_tspec; 3873 tspec_t ost = ostp->t_tspec; 3874 3875 if (nst == VOID || ost == VOID) { 3876 /* TODO: C99 behaves like C90 here. */ 3877 if (!allow_trad && !allow_c99 && (nst == FUNC || ost == FUNC)) { 3878 const char *nts, *ots; 3879 /* null pointers are already handled in convert() */ 3880 *(nst == FUNC ? &nts : &ots) = "function pointer"; 3881 *(nst == VOID ? &nts : &ots) = "'void *'"; 3882 /* conversion of %s to %s requires a cast */ 3883 warning(303, ots, nts); 3884 } 3885 return; 3886 } 3887 if (nst == FUNC && ost == FUNC) 3888 return; 3889 if (nst == FUNC || ost == FUNC) { 3890 /* converting '%s' to '%s' is questionable */ 3891 warning(229, type_name(otp), type_name(ntp)); 3892 return; 3893 } 3894 3895 if (hflag && alignment(nstp) > alignment(ostp) && 3896 !is_incomplete(ostp) && alignment(ostp) > 1 && 3897 !(nst == UNION && union_contains(nstp, ostp))) { 3898 /* converting '%s' to '%s' increases alignment ... */ 3899 warning(135, type_name(otp), type_name(ntp), 3900 alignment(ostp), alignment(nstp)); 3901 } 3902 3903 if (cflag && should_warn_about_pointer_cast(nstp, nst, ostp, ost)) { 3904 /* pointer cast from '%s' to unrelated '%s' */ 3905 warning(247, type_name(ostp), type_name(nstp)); 3906 } 3907 } 3908 3909 /* 3910 * Insert a conversion operator, which converts the type of the node 3911 * to another given type. 3912 * 3913 * Possible values for 'op': 3914 * CVT a cast-expression 3915 * binary integer promotion for one of the operands, or a usual 3916 * arithmetic conversion 3917 * binary plain or compound assignments to bit-fields 3918 * FARG 'arg' is the number of the parameter (used for warnings) 3919 * NOOP several other implicit conversions 3920 * ... 3921 */ 3922 tnode_t * 3923 convert(op_t op, int arg, type_t *tp, tnode_t *tn) 3924 { 3925 tspec_t nt = tp->t_tspec; 3926 tspec_t ot = tn->tn_type->t_tspec; 3927 3928 if (allow_trad && allow_c90 && op == FARG) 3929 check_prototype_conversion(arg, nt, ot, tp, tn); 3930 3931 if (nt == BOOL) { 3932 /* No further checks. */ 3933 3934 } else if (is_integer(nt)) { 3935 if (ot == BOOL) { 3936 /* No further checks. */ 3937 } else if (is_integer(ot)) 3938 convert_integer_from_integer(op, arg, nt, ot, tp, tn); 3939 else if (is_floating(ot)) 3940 convert_integer_from_floating(op, arg, tp, tn); 3941 else if (ot == PTR) 3942 convert_integer_from_pointer(op, nt, tp, tn); 3943 3944 } else if (is_floating(nt)) { 3945 if (is_integer(ot) && op != CVT) { 3946 /* implicit conversion from integer '%s' to ... */ 3947 query_message(19, 3948 type_name(tn->tn_type), type_name(tp)); 3949 } 3950 3951 } else if (nt == PTR) { 3952 if (is_null_pointer(tn)) { 3953 /* a null pointer may be assigned to any pointer. */ 3954 } else if (ot == PTR && op == CVT) 3955 convert_pointer_from_pointer(tp, tn); 3956 } 3957 3958 tnode_t *ntn = expr_alloc_tnode(); 3959 ntn->tn_op = CVT; 3960 ntn->tn_type = tp; 3961 ntn->tn_cast = op == CVT; 3962 ntn->tn_sys |= tn->tn_sys; 3963 ntn->u.ops.right = NULL; 3964 if (tn->tn_op != CON || nt == VOID) { 3965 ntn->u.ops.left = tn; 3966 } else { 3967 ntn->tn_op = CON; 3968 convert_constant(op, arg, ntn->tn_type, &ntn->u.value, 3969 &tn->u.value); 3970 } 3971 3972 return ntn; 3973 } 3974 3975 static void 3976 convert_constant_from_floating(op_t op, int arg, const type_t *ntp, 3977 tspec_t nt, val_t *nv, val_t *ov) 3978 { 3979 long double max = 0.0, min = 0.0; 3980 3981 switch (nt) { 3982 case CHAR: 3983 max = TARG_CHAR_MAX; min = TARG_CHAR_MIN; break; 3984 case UCHAR: 3985 max = TARG_UCHAR_MAX; min = 0; break; 3986 case SCHAR: 3987 max = TARG_SCHAR_MAX; min = TARG_SCHAR_MIN; break; 3988 case SHORT: 3989 max = TARG_SHRT_MAX; min = TARG_SHRT_MIN; break; 3990 case USHORT: 3991 max = TARG_USHRT_MAX; min = 0; break; 3992 case ENUM: 3993 case INT: 3994 max = TARG_INT_MAX; min = TARG_INT_MIN; break; 3995 case UINT: 3996 max = TARG_UINT_MAX; min = 0; break; 3997 case LONG: 3998 max = TARG_LONG_MAX; min = TARG_LONG_MIN; break; 3999 case ULONG: 4000 max = TARG_ULONG_MAX; min = 0; break; 4001 case LLONG: 4002 max = LLONG_MAX; min = LLONG_MIN; break; 4003 case ULLONG: 4004 max = ULLONG_MAX; min = 0; break; 4005 case FLOAT: 4006 case FCOMPLEX: 4007 max = FLT_MAX; min = -FLT_MAX; break; 4008 case DOUBLE: 4009 case DCOMPLEX: 4010 max = DBL_MAX; min = -DBL_MAX; break; 4011 case LDOUBLE: 4012 case LCOMPLEX: 4013 /* LINTED 248; see floating_error_value. */ 4014 max = LDBL_MAX; min = -max; break; 4015 default: 4016 lint_assert(false); 4017 } 4018 if (ov->u.floating > max || ov->u.floating < min) { 4019 lint_assert(nt != LDOUBLE); 4020 const char *ot_name = type_name(gettyp(ov->v_tspec)); 4021 const char *nt_name = type_name(ntp); 4022 if (is_integer(nt)) 4023 goto after_warning; 4024 if (op == FARG) 4025 /* conversion of '%s' to '%s' is out of range, ... */ 4026 warning(295, ot_name, nt_name, arg); 4027 else 4028 /* conversion of '%s' to '%s' is out of range */ 4029 warning(119, ot_name, nt_name); 4030 after_warning: 4031 ov->u.floating = ov->u.floating > 0 ? max : min; 4032 } 4033 4034 if (nt == FLOAT || nt == FCOMPLEX) 4035 nv->u.floating = (float)ov->u.floating; 4036 else if (nt == DOUBLE || nt == DCOMPLEX) 4037 nv->u.floating = (double)ov->u.floating; 4038 else if (nt == LDOUBLE || nt == LCOMPLEX) 4039 nv->u.floating = ov->u.floating; 4040 else 4041 nv->u.integer = (int64_t)ov->u.floating; 4042 } 4043 4044 static bool 4045 convert_constant_to_floating(tspec_t nt, val_t *nv, 4046 tspec_t ot, const val_t *v) 4047 { 4048 if (nt == FLOAT) { 4049 nv->u.floating = (ot == PTR || is_uinteger(ot)) ? 4050 (float)(uint64_t)v->u.integer : (float)v->u.integer; 4051 } else if (nt == DOUBLE) { 4052 nv->u.floating = (ot == PTR || is_uinteger(ot)) ? 4053 (double)(uint64_t)v->u.integer : (double)v->u.integer; 4054 } else if (nt == LDOUBLE) { 4055 nv->u.floating = (ot == PTR || is_uinteger(ot)) 4056 ? (long double)(uint64_t)v->u.integer 4057 : (long double)v->u.integer; 4058 } else 4059 return false; 4060 return true; 4061 } 4062 4063 static void 4064 warn_constant_truncated(op_t op, const val_t *v) 4065 { 4066 char buf[256]; 4067 bool is_unsigned = is_uinteger(v->v_tspec); 4068 int64_t val = v->u.integer; 4069 unsigned long long abs_val = is_unsigned || val >= 0 4070 ? (unsigned long long)val 4071 : -(unsigned long long)val; 4072 const char *sign = is_unsigned || val >= 0 ? "" : "-"; 4073 snprintf(buf, sizeof(buf), "%s%#llx", sign, abs_val); 4074 /* constant %s truncated by conversion, op '%s' */ 4075 warning(306, buf, op_name(op)); 4076 } 4077 4078 static void 4079 convert_constant_check_range_bitor(size_t nsz, size_t osz, const val_t *v, 4080 uint64_t xmask, op_t op) 4081 { 4082 if (nsz < osz && (v->u.integer & xmask) != 0) 4083 warn_constant_truncated(op, v); 4084 } 4085 4086 static void 4087 convert_constant_check_range_bitand(size_t nsz, size_t osz, 4088 uint64_t xmask, const val_t *nv, 4089 tspec_t ot, const val_t *v, 4090 const type_t *tp, op_t op) 4091 { 4092 if (nsz > osz && 4093 (nv->u.integer & bit((unsigned int)(osz - 1))) != 0 && 4094 (nv->u.integer & xmask) != xmask) { 4095 /* '%s' converts '%s' with its most significant bit being set to '%s' */ 4096 warning(309, 4097 op_name(op), type_name(gettyp(ot)), type_name(tp)); 4098 } else if (nsz < osz && 4099 (v->u.integer & xmask) != xmask && 4100 (v->u.integer & xmask) != 0) 4101 warn_constant_truncated(op, v); 4102 } 4103 4104 static void 4105 convert_constant_check_range_signed(op_t op, int arg, 4106 const type_t *ntp, int64_t ov) 4107 { 4108 if (op == ASSIGN) 4109 /* assignment of negative constant %lld to unsigned ... */ 4110 warning(164, (long long)ov, type_name(ntp)); 4111 else if (op == INIT) 4112 /* initialization of unsigned type '%s' with negative ... */ 4113 warning(221, type_name(ntp), (long long)ov); 4114 else if (op == FARG) 4115 /* conversion of negative constant %lld to unsigned ... */ 4116 warning(296, (long long)ov, type_name(ntp), arg); 4117 else if (modtab[op].m_comparison) { 4118 /* handled by check_integer_comparison() */ 4119 } else 4120 /* conversion of negative constant %lld to unsigned ... */ 4121 warning(222, (long long)ov, type_name(ntp)); 4122 } 4123 4124 /* 4125 * Loss of significant bit(s). All truncated bits of unsigned types or all 4126 * truncated bits plus the msb of the target for signed types are considered 4127 * to be significant bits. Loss of significant bits means that at least one 4128 * of the bits was set in an unsigned type or that at least one but not all 4129 * of the bits was set in a signed type. Loss of significant bits means that 4130 * it is not possible, also not with necessary casts, to convert back to the 4131 * original type. An example for a necessary cast is: 4132 * char c; int i; c = 128; 4133 * i = c; ** yields -128 ** 4134 * i = (unsigned char)c; ** yields 128 ** 4135 */ 4136 static void 4137 warn_constant_check_range_truncated(op_t op, int arg, const type_t *tp, 4138 tspec_t ot) 4139 { 4140 if (op == ASSIGN && tp->t_bitfield) 4141 /* precision lost in bit-field assignment */ 4142 warning(166); 4143 else if (op == ASSIGN) 4144 /* constant truncated by assignment */ 4145 warning(165); 4146 else if (op == INIT && tp->t_bitfield) 4147 /* bit-field initializer does not fit */ 4148 warning(180); 4149 else if (op == INIT) 4150 /* initializer does not fit */ 4151 warning(178); 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 warn_constant_check_range_loss(op_t op, int arg, const type_t *tp, 4165 tspec_t ot) 4166 { 4167 if (op == ASSIGN && tp->t_bitfield) 4168 /* precision lost in bit-field assignment */ 4169 warning(166); 4170 else if (op == INIT && tp->t_bitfield) 4171 /* bit-field initializer out of range */ 4172 warning(11); 4173 else if (op == CASE) 4174 /* case label is converted from '%s' to '%s' */ 4175 warning(196, tspec_name(ot), type_name(tp)); 4176 else if (op == FARG) 4177 /* conversion of '%s' to '%s' is out of range, arg #%d */ 4178 warning(295, type_name(gettyp(ot)), type_name(tp), arg); 4179 else 4180 /* conversion of '%s' to '%s' is out of range */ 4181 warning(119, type_name(gettyp(ot)), type_name(tp)); 4182 } 4183 4184 static void 4185 convert_constant_check_range(tspec_t ot, const type_t *tp, tspec_t nt, 4186 op_t op, int arg, const val_t *v, val_t *nv) 4187 { 4188 unsigned int obitsz, nbitsz; 4189 uint64_t xmask, xmsk1; 4190 4191 obitsz = size_in_bits(ot); 4192 nbitsz = tp->t_bitfield ? tp->t_bit_field_width : size_in_bits(nt); 4193 xmask = value_bits(nbitsz) ^ value_bits(obitsz); 4194 xmsk1 = value_bits(nbitsz) ^ value_bits(obitsz - 1); 4195 if (op == ORASS || op == BITOR || op == BITXOR) { 4196 convert_constant_check_range_bitor( 4197 nbitsz, obitsz, v, xmask, op); 4198 } else if (op == ANDASS || op == BITAND) { 4199 convert_constant_check_range_bitand( 4200 nbitsz, obitsz, xmask, nv, ot, v, tp, op); 4201 } else if (nt != PTR && is_uinteger(nt) && 4202 ot != PTR && !is_uinteger(ot) && v->u.integer < 0) 4203 convert_constant_check_range_signed(op, arg, tp, v->u.integer); 4204 else if (nv->u.integer != v->u.integer && nbitsz <= obitsz && 4205 (v->u.integer & xmask) != 0 && 4206 (is_uinteger(ot) || (v->u.integer & xmsk1) != xmsk1)) 4207 warn_constant_check_range_truncated(op, arg, tp, ot); 4208 else if (nv->u.integer != v->u.integer) 4209 warn_constant_check_range_loss(op, arg, tp, ot); 4210 } 4211 4212 /* Converts a typed constant to a constant of another type. */ 4213 void 4214 convert_constant(op_t op, int arg, const type_t *ntp, val_t *nv, val_t *ov) 4215 { 4216 /* 4217 * TODO: make 'ov' const; the name of this function does not suggest 4218 * that it modifies 'ov'. 4219 */ 4220 tspec_t ot = ov->v_tspec; 4221 tspec_t nt = nv->v_tspec = ntp->t_tspec; 4222 bool range_check = false; 4223 4224 if (nt == BOOL) { /* C99 6.3.1.2 */ 4225 nv->v_unsigned_since_c90 = false; 4226 nv->u.integer = is_nonzero_val(ov) ? 1 : 0; 4227 return; 4228 } 4229 4230 if (ot == FLOAT || ot == DOUBLE || ot == LDOUBLE) 4231 convert_constant_from_floating(op, arg, ntp, nt, nv, ov); 4232 else if (!convert_constant_to_floating(nt, nv, ot, ov)) { 4233 range_check = true; /* Check for lost precision. */ 4234 nv->u.integer = ov->u.integer; 4235 } 4236 4237 if (allow_trad && allow_c90 && ov->v_unsigned_since_c90 && 4238 (is_floating(nt) || ( 4239 (is_integer(nt) && !is_uinteger(nt) && 4240 portable_rank_cmp(nt, ot) > 0)))) { 4241 /* C90 treats constant as unsigned */ 4242 warning(157); 4243 ov->v_unsigned_since_c90 = false; 4244 } 4245 4246 if (is_integer(nt)) { 4247 unsigned int size = ntp->t_bitfield 4248 ? ntp->t_bit_field_width : size_in_bits(nt); 4249 nv->u.integer = convert_integer(nv->u.integer, nt, size); 4250 } 4251 4252 if (range_check && op != CVT) 4253 convert_constant_check_range(ot, ntp, nt, op, arg, ov, nv); 4254 } 4255 4256 tnode_t * 4257 build_sizeof(const type_t *tp) 4258 { 4259 unsigned int size_in_bytes = type_size_in_bits(tp) / CHAR_SIZE; 4260 tnode_t *tn = build_integer_constant(SIZEOF_TSPEC, size_in_bytes); 4261 tn->tn_system_dependent = true; 4262 debug_step("build_sizeof '%s' = %u", type_name(tp), size_in_bytes); 4263 return tn; 4264 } 4265 4266 tnode_t * 4267 build_offsetof(const type_t *tp, designation dn) 4268 { 4269 unsigned int offset_in_bits = 0; 4270 4271 if (!is_struct_or_union(tp->t_tspec)) { 4272 /* unacceptable operand of '%s' */ 4273 error(111, "offsetof"); 4274 goto proceed; 4275 } 4276 for (size_t i = 0; i < dn.dn_len; i++) { 4277 const designator *dr = dn.dn_items + i; 4278 if (dr->dr_kind == DK_SUBSCRIPT) { 4279 if (tp->t_tspec != ARRAY) 4280 goto proceed; /* silent error */ 4281 tp = tp->t_subt; 4282 offset_in_bits += (unsigned)dr->dr_subscript 4283 * type_size_in_bits(tp); 4284 } else { 4285 if (!is_struct_or_union(tp->t_tspec)) 4286 goto proceed; /* silent error */ 4287 const char *name = dr->dr_member->s_name; 4288 sym_t *mem = find_member(tp->u.sou, name); 4289 if (mem == NULL) { 4290 /* type '%s' does not have member '%s' */ 4291 error(101, name, type_name(tp)); 4292 goto proceed; 4293 } 4294 tp = mem->s_type; 4295 offset_in_bits += mem->u.s_member.sm_offset_in_bits; 4296 } 4297 } 4298 free(dn.dn_items); 4299 4300 proceed:; 4301 unsigned int offset_in_bytes = offset_in_bits / CHAR_SIZE; 4302 tnode_t *tn = build_integer_constant(SIZEOF_TSPEC, offset_in_bytes); 4303 tn->tn_system_dependent = true; 4304 return tn; 4305 } 4306 4307 unsigned int 4308 type_size_in_bits(const type_t *tp) 4309 { 4310 4311 unsigned int elem = 1; 4312 bool flex = false; 4313 lint_assert(tp != NULL); 4314 while (tp->t_tspec == ARRAY) { 4315 flex = true; /* allow c99 flex arrays [] [0] */ 4316 elem *= tp->u.dimension; 4317 tp = tp->t_subt; 4318 } 4319 if (elem == 0 && !flex) { 4320 /* cannot take size/alignment of incomplete type */ 4321 error(143); 4322 elem = 1; 4323 } 4324 4325 unsigned int elsz; 4326 switch (tp->t_tspec) { 4327 case VOID: 4328 /* cannot take size/alignment of void */ 4329 error(146); 4330 elsz = 1; 4331 break; 4332 case FUNC: 4333 /* cannot take size/alignment of function type '%s' */ 4334 error(144, type_name(tp)); 4335 elsz = 1; 4336 break; 4337 case STRUCT: 4338 case UNION: 4339 if (is_incomplete(tp)) { 4340 /* cannot take size/alignment of incomplete type */ 4341 error(143); 4342 elsz = 1; 4343 } else 4344 elsz = tp->u.sou->sou_size_in_bits; 4345 break; 4346 case ENUM: 4347 if (is_incomplete(tp)) { 4348 /* cannot take size/alignment of incomplete type */ 4349 warning(143); 4350 } 4351 /* FALLTHROUGH */ 4352 default: 4353 if (tp->t_bitfield) 4354 /* cannot take size/alignment of bit-field */ 4355 error(145); 4356 elsz = size_in_bits(tp->t_tspec); 4357 lint_assert(elsz > 0); 4358 break; 4359 } 4360 4361 return elem * elsz; 4362 } 4363 4364 /* C11 6.5.3.4, GCC */ 4365 tnode_t * 4366 build_alignof(const type_t *tp) 4367 { 4368 if (tp->t_tspec == FUNC) { 4369 /* cannot take size/alignment of function type '%s' */ 4370 error(144, type_name(tp)); 4371 return NULL; 4372 } 4373 if (tp->t_tspec == VOID) { 4374 /* cannot take size/alignment of void */ 4375 error(146); 4376 return NULL; 4377 } 4378 if (is_incomplete(tp)) { 4379 /* cannot take size/alignment of incomplete type */ 4380 error(143); 4381 return NULL; 4382 } 4383 if (tp->t_bitfield) { 4384 /* cannot take size/alignment of bit-field */ 4385 error(145); 4386 return NULL; 4387 } 4388 return build_integer_constant(SIZEOF_TSPEC, (int64_t)alignment(tp)); 4389 } 4390 4391 static tnode_t * 4392 cast_to_union(tnode_t *otn, bool sys, type_t *ntp) 4393 { 4394 4395 if (!allow_gcc) { 4396 /* union cast is a GCC extension */ 4397 error(328); 4398 return NULL; 4399 } 4400 4401 for (const sym_t *m = ntp->u.sou->sou_first_member; 4402 m != NULL; m = m->s_next) { 4403 if (types_compatible(m->s_type, otn->tn_type, 4404 false, false, NULL)) { 4405 tnode_t *ntn = build_op(CVT, sys, ntp, otn, NULL); 4406 ntn->tn_cast = true; 4407 return ntn; 4408 } 4409 } 4410 4411 /* type '%s' is not a member of '%s' */ 4412 error(329, type_name(otn->tn_type), type_name(ntp)); 4413 return NULL; 4414 } 4415 4416 // In GCC mode, allow 'nullptr + offset' as a constant expression. 4417 static tnode_t * 4418 null_pointer_offset(tnode_t *tn) 4419 { 4420 uint64_t off = 0; 4421 const tnode_t *n = tn; 4422 while ((n->tn_op == PLUS || n->tn_op == MINUS) 4423 && is_integer(n->u.ops.right->tn_type->t_tspec)) { 4424 off += (uint64_t)n->u.ops.right->u.value.u.integer; 4425 n = n->u.ops.left; 4426 } 4427 if (n->tn_type->t_tspec == PTR 4428 && n->tn_op == ADDR 4429 && n->u.ops.left->tn_op == INDIR 4430 && n->u.ops.left->u.ops.left->tn_op == CON 4431 && n->u.ops.left->u.ops.left->tn_type->t_tspec == PTR) { 4432 off += (uint64_t)n->u.ops.left->u.ops.left->u.value.u.integer; 4433 return build_integer_constant(SIZEOF_TSPEC, (int64_t)off); 4434 } 4435 return tn; 4436 } 4437 4438 tnode_t * 4439 cast(tnode_t *tn, bool sys, type_t *tp) 4440 { 4441 4442 if (tn == NULL) 4443 return NULL; 4444 4445 tn = cconv(tn); 4446 4447 lint_assert(tp != NULL); 4448 tspec_t nt = tp->t_tspec; 4449 tspec_t ot = tn->tn_type->t_tspec; 4450 4451 if (nt == VOID) { 4452 /* 4453 * C90 6.3.4, C99 6.5.4p2 and C11 6.5.4p2 allow any type to be 4454 * cast to void. The only other allowed casts are from a 4455 * scalar type to a scalar type. 4456 */ 4457 } else if (nt == UNION) 4458 return cast_to_union(tn, sys, tp); 4459 else if (nt == STRUCT || nt == ARRAY || nt == FUNC) { 4460 /* Casting to a struct is an undocumented GCC extension. */ 4461 if (!(allow_gcc && nt == STRUCT)) 4462 goto invalid_cast; 4463 } else if (is_struct_or_union(ot)) 4464 goto invalid_cast; 4465 else if (ot == VOID) { 4466 /* improper cast of void expression */ 4467 error(148); 4468 return NULL; 4469 } else if (is_integer(nt) && is_scalar(ot)) { 4470 tn = null_pointer_offset(tn); 4471 } else if (is_floating(nt) && is_arithmetic(ot)) { 4472 /* ok */ 4473 } else if (nt == PTR && is_integer(ot)) { 4474 /* ok */ 4475 } else if (nt == PTR && ot == PTR) { 4476 if (!tp->t_subt->t_const && tn->tn_type->t_subt->t_const) { 4477 if (hflag) 4478 /* cast discards 'const' from type '%s' */ 4479 warning(275, type_name(tn->tn_type)); 4480 } 4481 } else 4482 goto invalid_cast; 4483 4484 if (any_query_enabled 4485 && types_compatible(tp, tn->tn_type, false, false, NULL)) 4486 /* no-op cast from '%s' to '%s' */ 4487 query_message(6, type_name(tn->tn_type), type_name(tp)); 4488 4489 tn = convert(CVT, 0, tp, tn); 4490 tn->tn_cast = true; 4491 tn->tn_sys = sys; 4492 4493 return tn; 4494 4495 invalid_cast: 4496 /* invalid cast from '%s' to '%s' */ 4497 error(147, type_name(tn->tn_type), type_name(tp)); 4498 return NULL; 4499 } 4500 4501 void 4502 add_function_argument(function_call *call, tnode_t *arg) 4503 { 4504 /* 4505 * If there was a serious error in the expression for the argument, 4506 * create a dummy argument so the positions of the remaining arguments 4507 * will not change. 4508 */ 4509 if (arg == NULL) 4510 arg = build_integer_constant(INT, 0); 4511 4512 if (call->args_len >= call->args_cap) { 4513 call->args_cap += 8; 4514 tnode_t **new_args = expr_zero_alloc( 4515 call->args_cap * sizeof(*call->args), "tnode*[]"); 4516 if (call->args_len > 0) 4517 memcpy(new_args, call->args, 4518 call->args_len * sizeof(*call->args)); 4519 call->args = new_args; 4520 } 4521 call->args[call->args_len++] = arg; 4522 } 4523 4524 /* 4525 * Compare the type of an argument with the corresponding type of a 4526 * prototype parameter. If it is a valid combination, but both types 4527 * are not the same, insert a conversion to convert the argument into 4528 * the type of the parameter. 4529 */ 4530 static tnode_t * 4531 check_prototype_argument(const function_call *call, int arg, 4532 type_t *tp, tnode_t *tn) 4533 { 4534 tnode_t *ln = xcalloc(1, sizeof(*ln)); 4535 ln->tn_type = expr_unqualified_type(tp); 4536 ln->tn_lvalue = true; 4537 if (typeok(FARG, call, arg, ln, tn)) { 4538 bool dowarn; 4539 if (!types_compatible(tp, tn->tn_type, 4540 true, false, (dowarn = false, &dowarn)) || dowarn) 4541 tn = convert(FARG, arg, tp, tn); 4542 } 4543 free(ln); 4544 return tn; 4545 } 4546 4547 /* 4548 * Check types of all function arguments and insert conversions, 4549 * if necessary. 4550 */ 4551 static void 4552 check_function_arguments(const function_call *call) 4553 { 4554 type_t *ftp = call->func->tn_type->t_subt; 4555 4556 /* get # of parameters in the prototype */ 4557 int npar = 0; 4558 for (const sym_t *p = ftp->u.params; p != NULL; p = p->s_next) 4559 npar++; 4560 4561 int narg = (int)call->args_len; 4562 4563 const sym_t *param = ftp->u.params; 4564 if (ftp->t_proto && npar != narg && !(ftp->t_vararg && npar < narg)) { 4565 /* argument mismatch: %d %s passed, %d expected */ 4566 error(150, narg, narg != 1 ? "arguments" : "argument", npar); 4567 param = NULL; 4568 } 4569 4570 for (int i = 0; i < narg; i++) { 4571 tnode_t *arg = call->args[i]; 4572 4573 /* some things which are always not allowed */ 4574 tspec_t at = arg->tn_type->t_tspec; 4575 if (at == VOID) { 4576 /* void expressions may not be arguments, arg #%d */ 4577 error(151, i + 1); 4578 return; 4579 } 4580 if (is_struct_or_union(at) && is_incomplete(arg->tn_type)) { 4581 /* argument cannot have unknown size, arg #%d */ 4582 error(152, i + 1); 4583 return; 4584 } 4585 if (is_integer(at) && 4586 arg->tn_type->t_is_enum && 4587 is_incomplete(arg->tn_type)) { 4588 /* argument cannot have unknown size, arg #%d */ 4589 warning(152, i + 1); 4590 } 4591 4592 arg = cconv(arg); 4593 call->args[i] = arg; 4594 4595 arg = param != NULL 4596 ? check_prototype_argument(call, i + 1, param->s_type, arg) 4597 : promote(NOOP, true, arg); 4598 call->args[i] = arg; 4599 4600 if (param != NULL) 4601 param = param->s_next; 4602 } 4603 } 4604 4605 tnode_t * 4606 build_function_call(tnode_t *func, bool sys, function_call *call) 4607 { 4608 4609 if (func == NULL) 4610 return NULL; 4611 4612 call->func = func; 4613 check_ctype_function_call(call); 4614 4615 func = cconv(func); 4616 call->func = func; 4617 4618 if (func->tn_type->t_tspec != PTR || 4619 func->tn_type->t_subt->t_tspec != FUNC) { 4620 /* cannot call '%s', must be a function */ 4621 error(149, type_name(func->tn_type)); 4622 return NULL; 4623 } 4624 4625 check_function_arguments(call); 4626 4627 tnode_t *ntn = expr_alloc_tnode(); 4628 ntn->tn_op = CALL; 4629 ntn->tn_type = func->tn_type->t_subt->t_subt; 4630 ntn->tn_sys = sys; 4631 ntn->u.call = call; 4632 return ntn; 4633 } 4634 4635 /* 4636 * Return the value of an integral constant expression. 4637 * If the expression is not constant or its type is not an integer 4638 * type, an error message is printed. 4639 */ 4640 val_t * 4641 integer_constant(tnode_t *tn, bool required) 4642 { 4643 4644 if (tn != NULL) 4645 tn = cconv(tn); 4646 if (tn != NULL) 4647 tn = promote(NOOP, false, tn); 4648 4649 val_t *v = xcalloc(1, sizeof(*v)); 4650 4651 if (tn == NULL) { 4652 lint_assert(seen_error); 4653 debug_step("constant node is null; returning 1 instead"); 4654 v->v_tspec = INT; 4655 v->u.integer = 1; 4656 return v; 4657 } 4658 4659 v->v_tspec = tn->tn_type->t_tspec; 4660 4661 if (tn->tn_op == CON) { 4662 lint_assert(tn->tn_type->t_tspec == tn->u.value.v_tspec); 4663 if (is_integer(tn->u.value.v_tspec)) { 4664 v->v_unsigned_since_c90 = 4665 tn->u.value.v_unsigned_since_c90; 4666 v->u.integer = tn->u.value.u.integer; 4667 return v; 4668 } 4669 v->u.integer = (int64_t)tn->u.value.u.floating; 4670 } else 4671 v->u.integer = 1; 4672 4673 if (required) 4674 /* integral constant expression expected */ 4675 error(55); 4676 else 4677 /* variable array dimension is a C99/GCC extension */ 4678 c99ism(318); 4679 4680 if (!is_integer(v->v_tspec)) 4681 v->v_tspec = INT; 4682 4683 return v; 4684 } 4685 4686 /* 4687 * Perform some tests on expressions which can't be done in build_binary() 4688 * and functions called by build_binary(). These tests must be done here 4689 * because we need some information about the context in which the operations 4690 * are performed. 4691 * After all tests are performed, if free_expr is true, expr() frees the 4692 * memory for the expression. 4693 */ 4694 void 4695 expr(tnode_t *tn, bool used, bool cond, bool free_expr, bool is_do_while, 4696 const char *stmt_kind) 4697 { 4698 4699 if (tn == NULL) { /* in case of errors */ 4700 expr_free_all(); 4701 return; 4702 } 4703 4704 /* expr() is also called in global initializations */ 4705 if (dcs->d_kind != DLK_EXTERN && !is_do_while) 4706 check_statement_reachable(stmt_kind); 4707 4708 check_expr_misc(tn, used, cond, !cond, false, false, false); 4709 if (tn->tn_op == ASSIGN && !tn->tn_parenthesized) { 4710 if (hflag && cond) 4711 /* assignment in conditional context */ 4712 warning(159); 4713 } 4714 if (!modtab[tn->tn_op].m_has_side_effect) { 4715 /* 4716 * for left operands of COMMA this warning is already printed 4717 */ 4718 if (tn->tn_op != COMMA && !used && !cond) 4719 check_null_effect(tn); 4720 } 4721 debug_node(tn); 4722 4723 if (free_expr) 4724 expr_free_all(); 4725 } 4726 4727 /* If the expression has the form '*(arr + idx)', check the array index. */ 4728 static void 4729 check_array_index(const tnode_t *indir, bool taking_address) 4730 { 4731 const tnode_t *plus, *arr, *idx; 4732 4733 if (indir->tn_op == INDIR 4734 && (plus = indir->u.ops.left, plus->tn_op == PLUS) 4735 && plus->u.ops.left->tn_op == ADDR 4736 && (arr = plus->u.ops.left->u.ops.left, true) 4737 && (arr->tn_op == STRING || arr->tn_op == NAME) 4738 && arr->tn_type->t_tspec == ARRAY 4739 && (idx = plus->u.ops.right, idx->tn_op == CON) 4740 && (!is_incomplete(arr->tn_type) || idx->u.value.u.integer < 0)) 4741 goto proceed; 4742 return; 4743 4744 proceed:; 4745 int elsz = length_in_bits(arr->tn_type->t_subt, NULL); 4746 if (elsz == 0) 4747 return; 4748 elsz /= CHAR_SIZE; 4749 4750 /* Change the unit of the index from bytes to element size. */ 4751 int64_t con = is_uinteger(idx->tn_type->t_tspec) 4752 ? (int64_t)((uint64_t)idx->u.value.u.integer / elsz) 4753 : idx->u.value.u.integer / elsz; 4754 4755 int dim = arr->tn_type->u.dimension + (taking_address ? 1 : 0); 4756 4757 if (!is_uinteger(idx->tn_type->t_tspec) && con < 0) 4758 /* array subscript %jd cannot be negative */ 4759 warning(167, (intmax_t)con); 4760 else if (dim > 0 && (uint64_t)con >= (uint64_t)dim) 4761 /* array subscript %ju cannot be > %d */ 4762 warning(168, (uintmax_t)con, dim - 1); 4763 } 4764 4765 static void 4766 check_expr_addr(const tnode_t *ln, bool szof, bool fcall) 4767 { 4768 /* XXX: Taking warn_about_unreachable into account here feels wrong. */ 4769 if (ln->tn_op == NAME && (reached || !warn_about_unreachable)) { 4770 if (!szof) 4771 mark_as_set(ln->u.sym); 4772 mark_as_used(ln->u.sym, fcall, szof); 4773 } 4774 check_array_index(ln, true); 4775 } 4776 4777 /* 4778 * If there is an asm statement in one of the compound statements around, 4779 * there may be other side effects, so don't warn. 4780 */ 4781 static bool 4782 is_asm_around(void) 4783 { 4784 for (decl_level *dl = dcs; dl != NULL; dl = dl->d_enclosing) 4785 if (dl->d_asm) 4786 return true; 4787 return false; 4788 } 4789 4790 static void 4791 check_expr_side_effect(const tnode_t *ln, bool szof) 4792 { 4793 4794 /* XXX: Taking warn_about_unreachable into account here feels wrong. */ 4795 if (ln->tn_op == NAME && (reached || !warn_about_unreachable)) { 4796 scl_t sc = ln->u.sym->s_scl; 4797 if (sc != EXTERN && sc != STATIC && 4798 !ln->u.sym->s_set && !szof && !is_asm_around()) { 4799 /* '%s' may be used before set */ 4800 warning(158, ln->u.sym->s_name); 4801 mark_as_set(ln->u.sym); 4802 } 4803 mark_as_used(ln->u.sym, false, false); 4804 } 4805 } 4806 4807 static void 4808 check_expr_assign(const tnode_t *ln, bool szof) 4809 { 4810 /* XXX: Taking warn_about_unreachable into account here feels wrong. */ 4811 if (ln->tn_op == NAME && !szof && (reached || !warn_about_unreachable)) { 4812 mark_as_set(ln->u.sym); 4813 if (ln->u.sym->s_scl == EXTERN) 4814 outusg(ln->u.sym); 4815 } 4816 check_array_index(ln, false); 4817 } 4818 4819 static void 4820 check_expr_call(const tnode_t *tn, const tnode_t *ln, 4821 bool szof, bool vctx, bool cond, bool retval_discarded) 4822 { 4823 lint_assert(ln->tn_op == ADDR); 4824 lint_assert(ln->u.ops.left->tn_op == NAME); 4825 if (!szof && !is_compiler_builtin(ln->u.ops.left->u.sym->s_name)) 4826 outcall(tn, vctx || cond, retval_discarded); 4827 4828 const function_call *call = tn->u.call; 4829 if (call->args_len == 4 || call->args_len == 5) 4830 check_snprintb(call); 4831 } 4832 4833 static void 4834 check_expr_op(op_t op, const tnode_t *ln, bool szof, bool fcall, bool eqwarn) 4835 { 4836 switch (op) { 4837 case ADDR: 4838 check_expr_addr(ln, szof, fcall); 4839 break; 4840 case LOAD: 4841 check_array_index(ln, false); 4842 /* FALLTHROUGH */ 4843 case INCBEF: 4844 case DECBEF: 4845 case INCAFT: 4846 case DECAFT: 4847 case ADDASS: 4848 case SUBASS: 4849 case MULASS: 4850 case DIVASS: 4851 case MODASS: 4852 case ANDASS: 4853 case ORASS: 4854 case XORASS: 4855 case SHLASS: 4856 case SHRASS: 4857 case REAL: 4858 case IMAG: 4859 check_expr_side_effect(ln, szof); 4860 break; 4861 case ASSIGN: 4862 check_expr_assign(ln, szof); 4863 break; 4864 case EQ: 4865 if (hflag && eqwarn) 4866 /* operator '==' found where '=' was expected */ 4867 warning(160); 4868 break; 4869 default: 4870 break; 4871 } 4872 } 4873 4874 /* 4875 * vctx ??? 4876 * cond whether the expression is a condition that 4877 * will be compared with 0 4878 * eqwarn whether the operator '==' might be a 4879 * misspelled '=' 4880 * fcall whether the expression is a function call 4881 * retval_discarded whether the return value of a function call 4882 * is discarded; such calls will be analyzed by 4883 * lint2 in messages 4, 8 and 9 4884 * szof whether the expression is part of a sizeof 4885 * expression, which means that its value is 4886 * discarded since only the type is relevant 4887 */ 4888 void 4889 check_expr_misc(const tnode_t *tn, bool vctx, bool cond, 4890 bool eqwarn, bool fcall, bool retval_discarded, bool szof) 4891 { 4892 4893 if (tn == NULL) 4894 return; 4895 op_t op = tn->tn_op; 4896 if (op == NAME || op == CON || op == STRING) 4897 return; 4898 bool is_direct = op == CALL 4899 && tn->u.call->func->tn_op == ADDR 4900 && tn->u.call->func->u.ops.left->tn_op == NAME; 4901 if (op == CALL) { 4902 const function_call *call = tn->u.call; 4903 if (is_direct) 4904 check_expr_call(tn, call->func, 4905 szof, vctx, cond, retval_discarded); 4906 bool discard = op == CVT && tn->tn_type->t_tspec == VOID; 4907 check_expr_misc(call->func, false, false, false, is_direct, 4908 discard, szof); 4909 for (size_t i = 0, n = call->args_len; i < n; i++) 4910 check_expr_misc(call->args[i], 4911 true, false, false, false, false, szof); 4912 return; 4913 } 4914 4915 lint_assert(has_operands(tn)); 4916 tnode_t *ln = tn->u.ops.left; 4917 tnode_t *rn = tn->u.ops.right; 4918 check_expr_op(op, ln, szof, fcall, eqwarn); 4919 4920 const mod_t *mp = &modtab[op]; 4921 bool cvctx = mp->m_value_context; 4922 bool ccond = mp->m_compares_with_zero; 4923 bool eq = mp->m_warn_if_operand_eq && 4924 !ln->tn_parenthesized && 4925 rn != NULL && !rn->tn_parenthesized; 4926 4927 /* 4928 * Values of operands of ':' are not used if the type of at least 4929 * one of the operands (for GCC compatibility) is 'void'. 4930 * 4931 * XXX test/value context of QUEST should probably be used as 4932 * context for both operands of COLON. 4933 */ 4934 if (op == COLON && tn->tn_type->t_tspec == VOID) 4935 cvctx = ccond = false; 4936 bool discard = op == CVT && tn->tn_type->t_tspec == VOID; 4937 check_expr_misc(ln, cvctx, ccond, eq, is_direct, discard, szof); 4938 4939 switch (op) { 4940 case LOGAND: 4941 case LOGOR: 4942 check_expr_misc(rn, false, true, eq, false, false, szof); 4943 break; 4944 case COLON: 4945 check_expr_misc(rn, cvctx, ccond, eq, false, false, szof); 4946 break; 4947 case COMMA: 4948 check_expr_misc(rn, vctx, cond, false, false, false, szof); 4949 break; 4950 default: 4951 if (mp->m_binary) 4952 check_expr_misc(rn, true, false, eq, false, false, 4953 szof); 4954 break; 4955 } 4956 } 4957 4958 /* 4959 * Return whether the expression can be used for static initialization. 4960 * 4961 * Constant initialization expressions must be constant or an address 4962 * of a static object with an optional offset. In the first case, 4963 * the result is returned in *offsp. In the second case, the static 4964 * object is returned in *symp and the offset in *offsp. 4965 * 4966 * The expression can consist of PLUS, MINUS, ADDR, NAME, STRING and 4967 * CON. Type conversions are allowed if they do not change binary 4968 * representation (including width). 4969 * 4970 * C99 6.6 "Constant expressions" 4971 * C99 6.7.8p4 restricts initializers for static storage duration 4972 */ 4973 bool 4974 constant_addr(const tnode_t *tn, const sym_t **symp, ptrdiff_t *offsp) 4975 { 4976 const sym_t *sym; 4977 ptrdiff_t offs1, offs2; 4978 tspec_t t, ot; 4979 4980 switch (tn->tn_op) { 4981 case MINUS: 4982 if (tn->u.ops.right->tn_op == CVT) 4983 return constant_addr(tn->u.ops.right, symp, offsp); 4984 if (tn->u.ops.right->tn_op != CON) 4985 return false; 4986 /* FALLTHROUGH */ 4987 case PLUS: 4988 offs1 = offs2 = 0; 4989 if (tn->u.ops.left->tn_op == CON) { 4990 offs1 = (ptrdiff_t)tn->u.ops.left->u.value.u.integer; 4991 if (!constant_addr(tn->u.ops.right, &sym, &offs2)) 4992 return false; 4993 } else if (tn->u.ops.right->tn_op == CON) { 4994 offs2 = (ptrdiff_t)tn->u.ops.right->u.value.u.integer; 4995 if (tn->tn_op == MINUS) 4996 offs2 = -offs2; 4997 if (!constant_addr(tn->u.ops.left, &sym, &offs1)) 4998 return false; 4999 } else { 5000 return false; 5001 } 5002 *symp = sym; 5003 *offsp = offs1 + offs2; 5004 return true; 5005 case ADDR: 5006 if (tn->u.ops.left->tn_op == NAME) { 5007 *symp = tn->u.ops.left->u.sym; 5008 *offsp = 0; 5009 return true; 5010 } 5011 *symp = NULL; 5012 *offsp = 0; 5013 return true; 5014 case CVT: 5015 t = tn->tn_type->t_tspec; 5016 ot = tn->u.ops.left->tn_type->t_tspec; 5017 if ((!is_integer(t) && t != PTR) || 5018 (!is_integer(ot) && ot != PTR)) { 5019 return false; 5020 } 5021 #if 0 5022 /*- 5023 * consider: 5024 * struct foo { 5025 * unsigned char a; 5026 * } f = { 5027 * (unsigned char)(unsigned long) 5028 * (&(((struct foo *)0)->a)) 5029 * }; 5030 * since psize(unsigned long) != psize(unsigned char), 5031 * this fails. 5032 */ 5033 else if (psize(t) != psize(ot)) 5034 return -1; 5035 #endif 5036 return constant_addr(tn->u.ops.left, symp, offsp); 5037 default: 5038 return false; 5039 } 5040 } 5041 5042 /* Append s2 to s1, then free s2. */ 5043 buffer * 5044 cat_strings(buffer *s1, buffer *s2) 5045 { 5046 5047 if ((s1->data != NULL) != (s2->data != NULL)) { 5048 /* cannot concatenate wide and regular string literals */ 5049 error(292); 5050 return s1; 5051 } 5052 5053 if (s1->data != NULL) { 5054 while (s1->len + s2->len + 1 > s1->cap) 5055 s1->cap *= 2; 5056 s1->data = xrealloc(s1->data, s1->cap); 5057 memcpy(s1->data + s1->len, s2->data, s2->len + 1); 5058 free(s2->data); 5059 } 5060 s1->len += s2->len; 5061 free(s2); 5062 5063 return s1; 5064 } 5065 5066 5067 typedef struct stmt_expr { 5068 memory_pool se_mem; 5069 sym_t *se_sym; 5070 struct stmt_expr *se_enclosing; 5071 } stmt_expr; 5072 5073 static stmt_expr *stmt_exprs; 5074 5075 void 5076 begin_statement_expr(void) 5077 { 5078 debug_enter(); 5079 5080 stmt_expr *se = xmalloc(sizeof(*se)); 5081 se->se_mem = expr_save_memory(); 5082 se->se_sym = NULL; 5083 se->se_enclosing = stmt_exprs; 5084 stmt_exprs = se; 5085 } 5086 5087 void 5088 do_statement_expr(tnode_t *tn) 5089 { 5090 block_level--; 5091 mem_block_level--; 5092 stmt_exprs->se_sym = tn != NULL 5093 ? mktempsym(block_dup_type(tn->tn_type)) 5094 : NULL; /* after a syntax error */ 5095 mem_block_level++; 5096 block_level++; 5097 /* '({ ... })' is a GCC extension */ 5098 gnuism(320); 5099 } 5100 5101 tnode_t * 5102 end_statement_expr(void) 5103 { 5104 tnode_t *tn; 5105 5106 stmt_expr *se = stmt_exprs; 5107 if (se->se_sym == NULL) { 5108 tn = NULL; /* after a syntax error */ 5109 goto end; 5110 } 5111 5112 tn = build_name(se->se_sym, false); 5113 (void)expr_save_memory(); /* leak */ 5114 expr_restore_memory(se->se_mem); 5115 stmt_exprs = se->se_enclosing; 5116 free(se); 5117 5118 end: 5119 debug_leave(); 5120 return tn; 5121 } 5122 5123 bool 5124 in_statement_expr(void) 5125 { 5126 return stmt_exprs != NULL; 5127 } 5128
Indexes created Tue Sep 23 23:09:58 GMT 2025