tree.c revision 1.667
1 /* $NetBSD: tree.c,v 1.667 2025/01/02 17:35:01 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 1.667 2025/01/02 17:35:01 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_plus_sat(const type_t *tp, int64_t a, int64_t b) 151 { 152 if (b >= 0) { 153 int64_t max = si_max_value(tp); 154 return a <= max - b ? a + b : max; 155 } else { 156 int64_t min = si_min_value(tp); 157 return a >= min - b ? a + b : min; 158 } 159 } 160 161 static int64_t 162 si_minus_sat(const type_t *tp, int64_t a, int64_t b) 163 { 164 if (b >= 0) { 165 int64_t min = si_min_value(tp); 166 return a >= min + b ? a - b : min; 167 } else { 168 int64_t max = si_max_value(tp); 169 return a <= max + b ? a - b : max; 170 } 171 } 172 173 static bool 174 ic_maybe_signed(const type_t *tp, integer_constraints ic) 175 { 176 return !is_uinteger(tp->t_tspec) && ic.bclr >> 63 == 0; 177 } 178 179 static bool 180 ic_maybe_signed_binary(const type_t *tp, 181 integer_constraints a, integer_constraints b) 182 { 183 return !is_uinteger(tp->t_tspec) && (a.bclr & b.bclr) >> 63 == 0; 184 } 185 186 static integer_constraints 187 ic_any(const type_t *tp) 188 { 189 integer_constraints c; 190 191 unsigned width = width_in_bits(tp); 192 uint64_t vbits = value_bits(width); 193 if (is_uinteger(tp->t_tspec)) { 194 c.smin = width < 64 ? 0 : INT64_MIN; 195 c.smax = width < 64 ? (int64_t)vbits : INT64_MAX; 196 c.umin = 0; 197 c.umax = vbits; 198 c.bclr = ~c.umax; 199 } else { 200 c.smin = -1 - (int64_t)(vbits >> 1); 201 c.smax = (int64_t)(vbits >> 1); 202 c.umin = 0; 203 c.umax = UINT64_MAX; 204 c.bclr = 0; 205 } 206 return c; 207 } 208 209 static integer_constraints 210 ic_mult(const type_t *tp, integer_constraints a, integer_constraints b) 211 { 212 integer_constraints c; 213 214 if (ic_maybe_signed_binary(tp, a, b) 215 || (a.umax > 0 && b.umax > ic_any(tp).umax / a.umax)) 216 return ic_any(tp); 217 218 c.smin = INT64_MIN; 219 c.smax = INT64_MAX; 220 c.umin = a.umin * b.umin; 221 c.umax = a.umax * b.umax; 222 c.bclr = ~u64_fill_right(c.umax); 223 return c; 224 } 225 226 static integer_constraints 227 ic_div(const type_t *tp, integer_constraints a, integer_constraints b) 228 { 229 if (ic_maybe_signed_binary(tp, a, b)) 230 return ic_any(tp); 231 232 integer_constraints c; 233 c.smin = INT64_MIN; 234 c.smax = INT64_MAX; 235 c.umin = a.umin / u64_max(b.umax, 1); 236 c.umax = a.umax / u64_max(b.umin, 1); 237 c.bclr = ~u64_fill_right(c.umax); 238 return c; 239 } 240 241 static integer_constraints 242 ic_mod(const type_t *tp, integer_constraints a, integer_constraints b) 243 { 244 if (ic_maybe_signed_binary(tp, a, b)) { 245 uint64_t max_abs_b = u64_max(s64_abs(b.smin), s64_abs(b.smax)); 246 if (max_abs_b >> 63 != 0 || max_abs_b == 0) 247 return a; 248 249 integer_constraints c; 250 c.smin = s64_max(a.smin, -(int64_t)(max_abs_b - 1)); 251 c.smax = s64_min(a.smax, (int64_t)(max_abs_b - 1)); 252 c.umin = 0; 253 c.umax = UINT64_MAX; 254 c.bclr = 0; 255 return c; 256 } 257 258 integer_constraints c; 259 c.smin = INT64_MIN; 260 c.smax = INT64_MAX; 261 c.umin = 0; 262 c.umax = b.umax - 1; 263 c.bclr = ~u64_fill_right(c.umax); 264 return c; 265 } 266 267 static integer_constraints 268 ic_plus(const type_t *tp, integer_constraints a, integer_constraints b) 269 { 270 if (ic_maybe_signed_binary(tp, a, b)) { 271 integer_constraints c; 272 c.smin = si_plus_sat(tp, a.smin, b.smin); 273 c.smax = si_plus_sat(tp, a.smax, b.smax); 274 c.umin = c.smin >= 0 ? (uint64_t)c.smin : 0; 275 c.umax = c.smin >= 0 ? (uint64_t)c.smax : UINT64_MAX; 276 c.bclr = 0; 277 return c; 278 } 279 280 uint64_t max = ui_max_value(tp); 281 integer_constraints c; 282 c.smin = INT64_MIN; 283 c.smax = INT64_MAX; 284 if (b.umax <= max - a.umax) { 285 c.umin = a.umin + b.umin; 286 c.umax = a.umax + b.umax; 287 } else { 288 c.umin = 0; 289 c.umax = max; 290 } 291 if (c.umax >> 63 == 0) { 292 c.smin = 0; 293 c.smax = (int64_t)c.umax; 294 } 295 c.bclr = ~u64_fill_right(c.umax); 296 return c; 297 } 298 299 static integer_constraints 300 ic_minus(const type_t *tp, integer_constraints a, integer_constraints b) 301 { 302 integer_constraints c; 303 c.smin = si_minus_sat(tp, a.smin, b.smax); 304 c.smax = si_minus_sat(tp, a.smax, b.smin); 305 306 if (ic_maybe_signed_binary(tp, a, b)) { 307 c.umin = c.smin >= 0 ? (uint64_t)c.smin : 0; 308 c.umax = c.smin >= 0 ? (uint64_t)c.smax : UINT64_MAX; 309 } else if (a.umin >= b.umax) { 310 c.umin = a.umin - b.umax; 311 c.umax = a.umax - b.umin; 312 } else { 313 c.umin = 0; 314 c.umax = is_uinteger(tp->t_tspec) ? ui_max_value(tp) 315 : UINT64_MAX; 316 } 317 c.bclr = ~u64_fill_right(c.umax); 318 return c; 319 } 320 321 static integer_constraints 322 ic_shl(const type_t *tp, integer_constraints a, integer_constraints b) 323 { 324 if (ic_maybe_signed(tp, a)) 325 return ic_any(tp); 326 327 unsigned amount; 328 if (b.smin == b.smax && b.smin >= 0 && b.smin < 64) 329 amount = (unsigned)b.smin; 330 else if (b.umin == b.umax && b.umin < 64) 331 amount = (unsigned)b.umin; 332 else 333 return ic_any(tp); 334 335 integer_constraints c; 336 c.umin = a.umin << amount; 337 c.umax = a.umax << amount; 338 if (c.umax >> (width_in_bits(tp) - 1) == 0) { 339 c.smin = (int64_t)c.umin; 340 c.smax = (int64_t)c.umax; 341 } else { 342 c.smin = INT64_MIN; 343 c.smax = INT64_MAX; 344 } 345 c.bclr = a.bclr << amount | (((uint64_t)1 << amount) - 1); 346 return c; 347 } 348 349 static integer_constraints 350 ic_shr(const type_t *tp, integer_constraints a, integer_constraints b) 351 { 352 if (ic_maybe_signed(tp, a)) 353 return ic_any(tp); 354 355 unsigned amount; 356 if (b.smin == b.smax && b.smin >= 0 && b.smin < 64) 357 amount = (unsigned)b.smin; 358 else if (b.umin == b.umax && b.umin < 64) 359 amount = (unsigned)b.umin; 360 else 361 return ic_any(tp); 362 363 integer_constraints c; 364 c.smin = s64_shr(a.smin, amount); 365 c.smax = s64_shr(a.smax, amount); 366 c.umin = a.umin >> amount; 367 c.umax = a.umax >> amount; 368 c.bclr = a.bclr >> amount | ~(~(uint64_t)0 >> amount); 369 return c; 370 } 371 372 static integer_constraints 373 ic_bitand(integer_constraints a, integer_constraints b) 374 { 375 integer_constraints c; 376 c.smin = a.smin & b.smin; 377 c.smax = a.smax & b.smax; 378 c.umin = a.umin & b.umin; 379 c.umax = a.umax & b.umax; 380 c.bclr = a.bclr | b.bclr; 381 return c; 382 } 383 384 static integer_constraints 385 ic_bitxor(const type_t *tp, integer_constraints a, integer_constraints b) 386 { 387 if (ic_maybe_signed_binary(tp, a, b)) 388 return ic_any(tp); 389 390 integer_constraints c; 391 c.smin = a.smin & b.smin; 392 c.smax = a.smax | b.smax; 393 c.umin = a.umin & b.umin; 394 c.umax = a.umax | b.umax; 395 c.bclr = a.bclr & b.bclr; 396 return c; 397 } 398 399 static integer_constraints 400 ic_bitor(integer_constraints a, integer_constraints b) 401 { 402 integer_constraints c; 403 c.smin = a.smin | b.smin; 404 c.smax = a.smax | b.smax; 405 c.umin = a.umin | b.umin; 406 c.umax = a.umax | b.umax; 407 c.bclr = a.bclr & b.bclr; 408 return c; 409 } 410 411 static integer_constraints 412 ic_quest_colon(integer_constraints a, integer_constraints b) 413 { 414 integer_constraints c; 415 c.smin = s64_min(a.smin, b.smin); 416 c.smax = s64_max(a.smax, b.smax); 417 c.umin = u64_min(a.umin, b.umin); 418 c.umax = u64_max(a.umax, b.umax); 419 c.bclr = a.bclr & b.bclr; 420 return c; 421 } 422 423 static integer_constraints 424 ic_con(const type_t *tp, const val_t *v) 425 { 426 lint_assert(is_integer(tp->t_tspec)); 427 int64_t si = v->u.integer; 428 uint64_t ui = (uint64_t)si; 429 430 integer_constraints c; 431 c.smin = si; 432 c.smax = si; 433 c.umin = ui; 434 c.umax = ui; 435 c.bclr = ~ui; 436 return c; 437 } 438 439 static integer_constraints 440 ic_cvt(const type_t *ntp, const type_t *otp, integer_constraints a) 441 { 442 unsigned nw = width_in_bits(ntp); 443 unsigned ow = width_in_bits(otp); 444 bool nu = is_uinteger(ntp->t_tspec); 445 bool ou = is_uinteger(otp->t_tspec); 446 447 if (nw >= ow && nu == ou) 448 return a; 449 if (nw > ow && ou) 450 return a; 451 if (nu && (~value_bits(nw) & ~a.bclr) == 0) 452 return a; 453 return ic_any(ntp); 454 } 455 456 static integer_constraints 457 ic_expr(const tnode_t *tn) 458 { 459 integer_constraints lc, rc; 460 461 lint_assert(is_integer(tn->tn_type->t_tspec)); 462 463 switch (tn->tn_op) { 464 case MULT: 465 lc = ic_expr(before_conversion(tn->u.ops.left)); 466 rc = ic_expr(before_conversion(tn->u.ops.right)); 467 return ic_mult(tn->tn_type, lc, rc); 468 case DIV: 469 lc = ic_expr(before_conversion(tn->u.ops.left)); 470 rc = ic_expr(before_conversion(tn->u.ops.right)); 471 return ic_div(tn->tn_type, lc, rc); 472 case MOD: 473 lc = ic_expr(before_conversion(tn->u.ops.left)); 474 rc = ic_expr(before_conversion(tn->u.ops.right)); 475 return ic_mod(tn->tn_type, lc, rc); 476 case PLUS: 477 lc = ic_expr(before_conversion(tn->u.ops.left)); 478 rc = ic_expr(before_conversion(tn->u.ops.right)); 479 return ic_plus(tn->tn_type, lc, rc); 480 case MINUS: 481 lc = ic_expr(before_conversion(tn->u.ops.left)); 482 rc = ic_expr(before_conversion(tn->u.ops.right)); 483 return ic_minus(tn->tn_type, lc, rc); 484 case SHL: 485 lc = ic_expr(tn->u.ops.left); 486 rc = ic_expr(tn->u.ops.right); 487 return ic_shl(tn->tn_type, lc, rc); 488 case SHR: 489 lc = ic_expr(tn->u.ops.left); 490 rc = ic_expr(tn->u.ops.right); 491 return ic_shr(tn->tn_type, lc, rc); 492 case BITAND: 493 lc = ic_expr(tn->u.ops.left); 494 rc = ic_expr(tn->u.ops.right); 495 return ic_bitand(lc, rc); 496 case BITXOR: 497 lc = ic_expr(tn->u.ops.left); 498 rc = ic_expr(tn->u.ops.right); 499 return ic_bitxor(tn->tn_type, lc, rc); 500 case BITOR: 501 lc = ic_expr(tn->u.ops.left); 502 rc = ic_expr(tn->u.ops.right); 503 return ic_bitor(lc, rc); 504 case QUEST: 505 lc = ic_expr(tn->u.ops.right->u.ops.left); 506 rc = ic_expr(tn->u.ops.right->u.ops.right); 507 return ic_quest_colon(lc, rc); 508 case CON: 509 return ic_con(tn->tn_type, &tn->u.value); 510 case CVT: 511 if (!is_integer(tn->u.ops.left->tn_type->t_tspec)) 512 return ic_any(tn->tn_type); 513 lc = ic_expr(tn->u.ops.left); 514 return ic_cvt(tn->tn_type, tn->u.ops.left->tn_type, lc); 515 default: 516 return ic_any(tn->tn_type); 517 } 518 } 519 520 uint64_t 521 possible_bits(const tnode_t *tn) 522 { 523 return ~ic_expr(tn).bclr; 524 } 525 526 bool 527 attributes_contain(const attribute_list *attrs, const char *str) 528 { 529 for (size_t i = 0, n = attrs->len; i < n; i++) { 530 const attribute *attr = attrs->attrs + i; 531 if (attr->prefix == NULL && strcmp(attr->name, str) == 0) 532 return true; 533 } 534 return false; 535 } 536 537 /* Build 'pointer to tp', 'array of tp' or 'function returning tp'. */ 538 type_t * 539 block_derive_type(type_t *tp, tspec_t t) 540 { 541 542 type_t *tp2 = block_zero_alloc(sizeof(*tp2), "type"); 543 tp2->t_tspec = t; 544 tp2->t_subt = tp; 545 return tp2; 546 } 547 548 /* 549 * Derive 'pointer to tp' or 'function returning tp'. 550 * The memory is freed at the end of the current expression. 551 */ 552 type_t * 553 expr_derive_type(type_t *tp, tspec_t t) 554 { 555 556 type_t *tp2 = expr_zero_alloc(sizeof(*tp2), "type"); 557 tp2->t_tspec = t; 558 tp2->t_subt = tp; 559 return tp2; 560 } 561 562 /* Create an expression from a unary or binary operator and its operands. */ 563 static tnode_t * 564 build_op(op_t op, bool sys, type_t *type, tnode_t *ln, tnode_t *rn) 565 { 566 567 tnode_t *ntn = expr_alloc_tnode(); 568 ntn->tn_op = op; 569 ntn->tn_type = type; 570 ntn->tn_sys = sys; 571 ntn->u.ops.left = ln; 572 ntn->u.ops.right = rn; 573 574 if (op == INDIR || op == FSEL) { 575 lint_assert(ln->tn_type->t_tspec == PTR); 576 tspec_t t = ln->tn_type->t_subt->t_tspec; 577 ntn->tn_lvalue = t != FUNC && t != VOID; 578 } 579 580 return ntn; 581 } 582 583 tnode_t * 584 build_constant(type_t *tp, val_t *v) 585 { 586 587 tnode_t *n = expr_alloc_tnode(); 588 n->tn_op = CON; 589 n->tn_type = tp; 590 n->u.value = *v; 591 n->u.value.v_tspec = tp->t_tspec; 592 free(v); 593 return n; 594 } 595 596 static tnode_t * 597 build_integer_constant(tspec_t t, int64_t si) 598 { 599 600 tnode_t *n = expr_alloc_tnode(); 601 n->tn_op = CON; 602 n->tn_type = gettyp(t); 603 n->u.value.v_tspec = t; 604 n->u.value.v_unsigned_since_c90 = false; 605 n->u.value.v_char_constant = false; 606 n->u.value.u.integer = si; 607 return n; 608 } 609 610 static void 611 fallback_symbol(sym_t *sym) 612 { 613 614 if (Tflag && fallback_symbol_strict_bool(sym)) 615 return; 616 617 if (funcsym != NULL && (strcmp(sym->s_name, "__FUNCTION__") == 0 || 618 strcmp(sym->s_name, "__PRETTY_FUNCTION__") == 0)) { 619 /* __FUNCTION__/__PRETTY_FUNCTION__ is a GCC extension */ 620 gnuism(316); 621 goto return_function_name; 622 } 623 624 if (funcsym != NULL && strcmp(sym->s_name, "__func__") == 0) { 625 if (!allow_c99) 626 /* __func__ is a C99 feature */ 627 warning(317); 628 /* C11 6.4.2.2 */ 629 return_function_name: 630 sym->s_type = block_derive_type(gettyp(CHAR), ARRAY); 631 sym->s_type->t_const = true; 632 sym->s_type->u.dimension = (int)strlen(funcsym->s_name) + 1; 633 return; 634 } 635 636 /* '%s' undefined */ 637 error(99, sym->s_name); 638 } 639 640 /* 641 * Functions that are predeclared by GCC or other compilers can be called 642 * with arbitrary arguments. Since lint usually runs after a successful 643 * compilation, it's the compiler's job to catch any errors. 644 */ 645 bool 646 is_compiler_builtin(const char *name) 647 { 648 /* https://gcc.gnu.org/onlinedocs/gcc/C-Extensions.html */ 649 if (allow_gcc) { 650 if (strncmp(name, "__atomic_", 9) == 0 || 651 strncmp(name, "__builtin_", 10) == 0 || 652 strcmp(name, "alloca") == 0 || 653 /* obsolete but still in use, as of 2021 */ 654 strncmp(name, "__sync_", 7) == 0) 655 return true; 656 } 657 658 /* https://software.intel.com/sites/landingpage/IntrinsicsGuide/ */ 659 if (strncmp(name, "_mm_", 4) == 0) 660 return true; 661 662 return false; 663 } 664 665 static bool 666 str_ends_with(const char *haystack, const char *needle) 667 { 668 size_t hlen = strlen(haystack); 669 size_t nlen = strlen(needle); 670 671 return nlen <= hlen && 672 memcmp(haystack + hlen - nlen, needle, nlen) == 0; 673 } 674 675 /* https://gcc.gnu.org/onlinedocs/gcc/Integer-Overflow-Builtins.html */ 676 static bool 677 is_gcc_bool_builtin(const char *name) 678 { 679 return strncmp(name, "__builtin_", 10) == 0 && 680 (str_ends_with(name, "_overflow") || 681 str_ends_with(name, "_overflow_p")); 682 } 683 684 static void 685 build_name_call(sym_t *sym) 686 { 687 688 if (is_compiler_builtin(sym->s_name)) { 689 /* 690 * Do not warn about these, just assume that they are regular 691 * functions compatible with non-prototype calling conventions. 692 */ 693 if (allow_gcc && is_gcc_bool_builtin(sym->s_name)) 694 sym->s_type = gettyp(BOOL); 695 } else if (allow_c99) 696 /* function '%s' implicitly declared to return int */ 697 error(215, sym->s_name); 698 else if (!allow_trad) 699 /* function '%s' implicitly declared to return int */ 700 warning(215, sym->s_name); 701 702 /* XXX if !allow_c90, the symbol should be exported to level 0 */ 703 sym->s_type = block_derive_type(sym->s_type, FUNC); 704 } 705 706 /* Create a node for a name (symbol table entry). */ 707 tnode_t * 708 build_name(sym_t *sym, bool is_funcname) 709 { 710 711 if (sym->s_scl == NO_SCL && !in_gcc_attribute) { 712 sym->s_scl = EXTERN; 713 sym->s_def = DECL; 714 if (is_funcname) 715 build_name_call(sym); 716 else 717 fallback_symbol(sym); 718 } 719 720 lint_assert(sym->s_kind == SK_VCFT || sym->s_kind == SK_MEMBER); 721 722 tnode_t *n = expr_alloc_tnode(); 723 n->tn_type = sym->s_type; 724 if (sym->s_scl == BOOL_CONST) { 725 n->tn_op = CON; 726 n->u.value.v_tspec = BOOL; 727 n->u.value.v_unsigned_since_c90 = false; 728 n->u.value.v_char_constant = false; 729 n->u.value.u.integer = sym->u.s_bool_constant ? 1 : 0; 730 } else if (sym->s_scl == ENUM_CONST) { 731 n->tn_op = CON; 732 n->u.value.v_tspec = INT; /* ENUM is in n->tn_type */ 733 n->u.value.v_unsigned_since_c90 = false; 734 n->u.value.v_char_constant = false; 735 n->u.value.u.integer = sym->u.s_enum_constant; 736 } else { 737 n->tn_op = NAME; 738 n->u.sym = sym; 739 if (sym->s_kind == SK_VCFT && sym->s_type->t_tspec != FUNC) 740 n->tn_lvalue = true; 741 } 742 743 return n; 744 } 745 746 tnode_t * 747 build_string(buffer *lit) 748 { 749 size_t value_len = lit->len; 750 if (lit->data != NULL) { 751 quoted_iterator it = { .end = 0 }; 752 for (value_len = 0; quoted_next(lit, &it); value_len++) 753 continue; 754 } 755 756 type_t *tp = expr_zero_alloc(sizeof(*tp), "type"); 757 tp->t_tspec = ARRAY; 758 tp->t_subt = gettyp(lit->data != NULL ? CHAR : WCHAR_TSPEC); 759 tp->u.dimension = (int)(value_len + 1); 760 761 tnode_t *n = expr_alloc_tnode(); 762 n->tn_op = STRING; 763 n->tn_type = tp; 764 n->tn_lvalue = true; 765 766 n->u.str_literals = expr_zero_alloc(sizeof(*n->u.str_literals), "tnode.string"); 767 n->u.str_literals->len = lit->len; 768 769 if (lit->data != NULL) { 770 n->u.str_literals->data = expr_zero_alloc(lit->len + 1, 771 "tnode.string.data"); 772 (void)memcpy(n->u.str_literals->data, lit->data, lit->len + 1); 773 free(lit->data); 774 } 775 free(lit); 776 777 return n; 778 } 779 780 tnode_t * 781 build_generic_selection(const tnode_t *expr, 782 struct generic_association *sel) 783 { 784 tnode_t *default_result = NULL; 785 786 for (; sel != NULL; sel = sel->ga_prev) { 787 if (expr != NULL && 788 types_compatible(sel->ga_arg, expr->tn_type, 789 false, false, NULL)) 790 return sel->ga_result; 791 else if (sel->ga_arg == NULL) 792 default_result = sel->ga_result; 793 } 794 return default_result; 795 } 796 797 static bool 798 is_out_of_char_range(const tnode_t *tn) 799 { 800 return tn->tn_op == CON && 801 !tn->u.value.v_char_constant && 802 !(0 <= tn->u.value.u.integer && 803 tn->u.value.u.integer < 1 << (CHAR_SIZE - 1)); 804 } 805 806 static bool 807 check_nonportable_char_comparison(op_t op, 808 const tnode_t *ln, tspec_t lt, 809 const tnode_t *rn, tspec_t rt) 810 { 811 if (!(hflag || pflag)) 812 return true; 813 814 if (lt == CHAR && is_out_of_char_range(rn)) { 815 char buf[128]; 816 (void)snprintf(buf, sizeof(buf), "%s %d", 817 op_name(op), (int)rn->u.value.u.integer); 818 /* nonportable character comparison '%s' */ 819 warning(230, buf); 820 return false; 821 } 822 if (rt == CHAR && is_out_of_char_range(ln)) { 823 char buf[128]; 824 (void)snprintf(buf, sizeof(buf), "%d %s ?", 825 (int)ln->u.value.u.integer, op_name(op)); 826 /* nonportable character comparison '%s' */ 827 warning(230, buf); 828 return false; 829 } 830 return true; 831 } 832 833 static void 834 check_integer_comparison(op_t op, tnode_t *ln, tnode_t *rn) 835 { 836 837 tspec_t lt = ln->tn_type->t_tspec; 838 tspec_t rt = rn->tn_type->t_tspec; 839 840 if (ln->tn_op != CON && rn->tn_op != CON) 841 return; 842 843 if (!is_integer(lt) || !is_integer(rt)) 844 return; 845 846 if (any_query_enabled && !in_system_header) { 847 if (lt == CHAR && rn->tn_op == CON && 848 !rn->u.value.v_char_constant) { 849 /* comparison '%s' of 'char' with plain integer %d */ 850 query_message(14, 851 op_name(op), (int)rn->u.value.u.integer); 852 } 853 if (rt == CHAR && ln->tn_op == CON && 854 !ln->u.value.v_char_constant) { 855 /* comparison '%s' of 'char' with plain integer %d */ 856 query_message(14, 857 op_name(op), (int)ln->u.value.u.integer); 858 } 859 } 860 861 if (!check_nonportable_char_comparison(op, ln, lt, rn, rt)) 862 return; 863 864 if (is_uinteger(lt) && !is_uinteger(rt) && 865 rn->tn_op == CON && rn->u.value.u.integer <= 0) { 866 if (rn->u.value.u.integer < 0) { 867 /* operator '%s' compares '%s' with '%s' */ 868 warning(162, op_name(op), 869 type_name(ln->tn_type), "negative constant"); 870 } else if (op == LT || op == GE) 871 /* operator '%s' compares '%s' with '%s' */ 872 warning(162, op_name(op), type_name(ln->tn_type), "0"); 873 return; 874 } 875 if (is_uinteger(rt) && !is_uinteger(lt) && 876 ln->tn_op == CON && ln->u.value.u.integer <= 0) { 877 if (ln->u.value.u.integer < 0) { 878 /* operator '%s' compares '%s' with '%s' */ 879 warning(162, op_name(op), 880 "negative constant", type_name(rn->tn_type)); 881 } else if (op == GT || op == LE) 882 /* operator '%s' compares '%s' with '%s' */ 883 warning(162, op_name(op), "0", type_name(rn->tn_type)); 884 return; 885 } 886 } 887 888 static const tspec_t arith_rank[] = { 889 LDOUBLE, DOUBLE, FLOAT, 890 #ifdef INT128_SIZE 891 UINT128, INT128, 892 #endif 893 ULLONG, LLONG, 894 ULONG, LONG, 895 UINT, INT, 896 }; 897 898 /* Keep unsigned in traditional C */ 899 static tspec_t 900 usual_arithmetic_conversion_trad(tspec_t lt, tspec_t rt) 901 { 902 903 size_t i; 904 for (i = 0; arith_rank[i] != INT; i++) 905 if (lt == arith_rank[i] || rt == arith_rank[i]) 906 break; 907 908 tspec_t t = arith_rank[i]; 909 if (is_uinteger(lt) || is_uinteger(rt)) 910 if (is_integer(t) && !is_uinteger(t)) 911 return unsigned_type(t); 912 return t; 913 } 914 915 static tspec_t 916 usual_arithmetic_conversion_c90(tspec_t lt, tspec_t rt) 917 { 918 919 if (lt == rt) 920 return lt; 921 922 if (lt == LCOMPLEX || rt == LCOMPLEX) 923 return LCOMPLEX; 924 if (lt == DCOMPLEX || rt == DCOMPLEX) 925 return DCOMPLEX; 926 if (lt == FCOMPLEX || rt == FCOMPLEX) 927 return FCOMPLEX; 928 if (lt == LDOUBLE || rt == LDOUBLE) 929 return LDOUBLE; 930 if (lt == DOUBLE || rt == DOUBLE) 931 return DOUBLE; 932 if (lt == FLOAT || rt == FLOAT) 933 return FLOAT; 934 935 if (size_in_bits(lt) > size_in_bits(rt)) 936 return lt; 937 if (size_in_bits(lt) < size_in_bits(rt)) 938 return rt; 939 940 size_t i; 941 for (i = 3; arith_rank[i] != INT; i++) 942 if (arith_rank[i] == lt || arith_rank[i] == rt) 943 break; 944 if ((is_uinteger(lt) || is_uinteger(rt)) && 945 !is_uinteger(arith_rank[i])) 946 i--; 947 return arith_rank[i]; 948 } 949 950 static tnode_t * 951 apply_usual_arithmetic_conversions(op_t op, tnode_t *tn, tspec_t t) 952 { 953 type_t *ntp = expr_dup_type(tn->tn_type); 954 ntp->t_tspec = t; 955 if (tn->tn_op != CON) { 956 /* usual arithmetic conversion for '%s' from '%s' to '%s' */ 957 query_message(4, op_name(op), 958 type_name(tn->tn_type), type_name(ntp)); 959 } 960 return convert(op, 0, ntp, tn); 961 } 962 963 /* 964 * Apply the "usual arithmetic conversions" (C99 6.3.1.8), which gives both 965 * operands the same type. 966 */ 967 static void 968 balance(op_t op, tnode_t **lnp, tnode_t **rnp) 969 { 970 971 tspec_t lt = (*lnp)->tn_type->t_tspec; 972 tspec_t rt = (*rnp)->tn_type->t_tspec; 973 if (!is_arithmetic(lt) || !is_arithmetic(rt)) 974 return; 975 976 tspec_t t = allow_c90 977 ? usual_arithmetic_conversion_c90(lt, rt) 978 : usual_arithmetic_conversion_trad(lt, rt); 979 980 if (modtab[op].m_comparison 981 && is_integer(lt) && (*lnp)->tn_op != CON 982 && is_floating(t) && (*rnp)->tn_op == CON) 983 /* comparing integer '%s' to floating point constant %Lg */ 984 warning(379, type_name((*lnp)->tn_type), 985 (*rnp)->u.value.u.floating); 986 987 if (t != lt) 988 *lnp = apply_usual_arithmetic_conversions(op, *lnp, t); 989 if (t != rt) 990 *rnp = apply_usual_arithmetic_conversions(op, *rnp, t); 991 992 if (is_integer(t)) { 993 unsigned lw = width_in_bits((*lnp)->tn_type); 994 unsigned rw = width_in_bits((*rnp)->tn_type); 995 if (lw < rw) 996 *lnp = convert(NOOP, 0, (*rnp)->tn_type, *lnp); 997 if (rw < lw) 998 *rnp = convert(NOOP, 0, (*lnp)->tn_type, *rnp); 999 } 1000 } 1001 1002 static tnode_t * 1003 build_address(bool sys, tnode_t *tn, bool force) 1004 { 1005 tspec_t t; 1006 1007 if (!force && ((t = tn->tn_type->t_tspec) == ARRAY || t == FUNC)) { 1008 if (!allow_c90) 1009 /* '&' before array or function: ignored */ 1010 warning(127); 1011 return tn; 1012 } 1013 1014 /* eliminate '&*' */ 1015 if (tn->tn_op == INDIR && 1016 tn->u.ops.left->tn_type->t_tspec == PTR && 1017 tn->u.ops.left->tn_type->t_subt == tn->tn_type) { 1018 return tn->u.ops.left; 1019 } 1020 1021 return build_op(ADDR, sys, expr_derive_type(tn->tn_type, PTR), 1022 tn, NULL); 1023 } 1024 1025 static uint64_t 1026 fold_unsigned_integer(op_t op, uint64_t l, uint64_t r, 1027 uint64_t max_value, bool *overflow) 1028 { 1029 switch (op) { 1030 case COMPL: 1031 return ~l & max_value; 1032 case UPLUS: 1033 return +l; 1034 case UMINUS: 1035 return -l & max_value; 1036 case MULT: 1037 *overflow = r > 0 && l > max_value / r; 1038 return l * r; 1039 case DIV: 1040 if (r == 0) { 1041 /* division by 0 */ 1042 error(139); 1043 return max_value; 1044 } 1045 return l / r; 1046 case MOD: 1047 if (r == 0) { 1048 /* modulus by 0 */ 1049 error(140); 1050 return 0; 1051 } 1052 return l % r; 1053 case PLUS: 1054 *overflow = l > max_value - r; 1055 return l + r; 1056 case MINUS: 1057 *overflow = l < r; 1058 return l - r; 1059 case SHL: 1060 /* TODO: warn about out-of-bounds 'r'. */ 1061 /* TODO: warn about overflow. */ 1062 return l << (r & 63); 1063 case SHR: 1064 /* TODO: warn about out-of-bounds 'r'. */ 1065 return l >> (r & 63); 1066 case LT: 1067 return l < r ? 1 : 0; 1068 case LE: 1069 return l <= r ? 1 : 0; 1070 case GT: 1071 return l > r ? 1 : 0; 1072 case GE: 1073 return l >= r ? 1 : 0; 1074 case EQ: 1075 return l == r ? 1 : 0; 1076 case NE: 1077 return l != r ? 1 : 0; 1078 case BITAND: 1079 return l & r; 1080 case BITXOR: 1081 return l ^ r; 1082 case BITOR: 1083 return l | r; 1084 default: 1085 lint_assert(/*CONSTCOND*/false); 1086 /* NOTREACHED */ 1087 } 1088 } 1089 1090 static int64_t 1091 fold_signed_integer(op_t op, int64_t l, int64_t r, 1092 int64_t min_value, int64_t max_value, bool *overflow) 1093 { 1094 switch (op) { 1095 case COMPL: 1096 return ~l; 1097 case UPLUS: 1098 return +l; 1099 case UMINUS: 1100 *overflow = l == min_value; 1101 return *overflow ? l : -l; 1102 case MULT:; 1103 uint64_t al = l >= 0 ? (uint64_t)l : -(uint64_t)l; 1104 uint64_t ar = r >= 0 ? (uint64_t)r : -(uint64_t)r; 1105 bool neg = (l >= 0) != (r >= 0); 1106 uint64_t max_prod = (uint64_t)max_value + (neg ? 1 : 0); 1107 if (al > 0 && ar > max_prod / al) { 1108 *overflow = true; 1109 return neg ? min_value : max_value; 1110 } 1111 return l * r; 1112 case DIV: 1113 if (r == 0) { 1114 /* division by 0 */ 1115 error(139); 1116 return max_value; 1117 } 1118 if (l == min_value && r == -1) { 1119 *overflow = true; 1120 return l; 1121 } 1122 return l / r; 1123 case MOD: 1124 if (r == 0) { 1125 /* modulus by 0 */ 1126 error(140); 1127 return 0; 1128 } 1129 if (l == min_value && r == -1) { 1130 *overflow = true; 1131 return 0; 1132 } 1133 return l % r; 1134 case PLUS: 1135 if (r > 0 && l > max_value - r) { 1136 *overflow = true; 1137 return max_value; 1138 } 1139 if (r < 0 && l < min_value - r) { 1140 *overflow = true; 1141 return min_value; 1142 } 1143 return l + r; 1144 case MINUS: 1145 if (r > 0 && l < min_value + r) { 1146 *overflow = true; 1147 return min_value; 1148 } 1149 if (r < 0 && l > max_value + r) { 1150 *overflow = true; 1151 return max_value; 1152 } 1153 return l - r; 1154 case SHL: 1155 /* TODO: warn about out-of-bounds 'r'. */ 1156 /* TODO: warn about overflow. */ 1157 return l << (r & 63); 1158 case SHR: 1159 /* TODO: warn about out-of-bounds 'r'. */ 1160 return s64_shr(l, r & 63); 1161 case LT: 1162 return l < r ? 1 : 0; 1163 case LE: 1164 return l <= r ? 1 : 0; 1165 case GT: 1166 return l > r ? 1 : 0; 1167 case GE: 1168 return l >= r ? 1 : 0; 1169 case EQ: 1170 return l == r ? 1 : 0; 1171 case NE: 1172 return l != r ? 1 : 0; 1173 case BITAND: 1174 return l & r; 1175 case BITXOR: 1176 return l ^ r; 1177 case BITOR: 1178 return l | r; 1179 default: 1180 lint_assert(/*CONSTCOND*/false); 1181 /* NOTREACHED */ 1182 } 1183 } 1184 1185 static tnode_t * 1186 fold_constant_integer(tnode_t *tn) 1187 { 1188 1189 lint_assert(has_operands(tn)); 1190 tspec_t t = tn->u.ops.left->tn_type->t_tspec; 1191 int64_t l = tn->u.ops.left->u.value.u.integer; 1192 int64_t r = is_binary(tn) ? tn->u.ops.right->u.value.u.integer : 0; 1193 uint64_t mask = value_bits(size_in_bits(t)); 1194 1195 int64_t res; 1196 bool overflow = false; 1197 if (!is_integer(t) || is_uinteger(t)) { 1198 uint64_t u_res = fold_unsigned_integer(tn->tn_op, 1199 (uint64_t)l, (uint64_t)r, mask, &overflow); 1200 if (u_res > mask) 1201 overflow = true; 1202 res = (int64_t)u_res; 1203 if (overflow && hflag) { 1204 char buf[128]; 1205 if (is_binary(tn)) { 1206 snprintf(buf, sizeof(buf), "%ju %s %ju", 1207 (uintmax_t)l, op_name(tn->tn_op), 1208 (uintmax_t)r); 1209 } else { 1210 snprintf(buf, sizeof(buf), "%s%ju", 1211 op_name(tn->tn_op), (uintmax_t)l); 1212 } 1213 /* '%s' overflows '%s' */ 1214 warning(141, buf, type_name(tn->tn_type)); 1215 } 1216 } else { 1217 int64_t max_value = (int64_t)(mask >> 1); 1218 int64_t min_value = -max_value - 1; 1219 res = fold_signed_integer(tn->tn_op, 1220 l, r, min_value, max_value, &overflow); 1221 if (res < min_value || res > max_value) 1222 overflow = true; 1223 if (overflow && hflag) { 1224 char buf[128]; 1225 if (is_binary(tn)) { 1226 snprintf(buf, sizeof(buf), "%jd %s %jd", 1227 (intmax_t)l, op_name(tn->tn_op), 1228 (intmax_t)r); 1229 } else if (tn->tn_op == UMINUS && l < 0) { 1230 snprintf(buf, sizeof(buf), "-(%jd)", 1231 (intmax_t)l); 1232 } else { 1233 snprintf(buf, sizeof(buf), "%s%jd", 1234 op_name(tn->tn_op), (intmax_t)l); 1235 } 1236 /* '%s' overflows '%s' */ 1237 warning(141, buf, type_name(tn->tn_type)); 1238 } 1239 } 1240 1241 val_t *v = xcalloc(1, sizeof(*v)); 1242 v->v_tspec = tn->tn_type->t_tspec; 1243 v->u.integer = convert_integer(res, t, size_in_bits(t)); 1244 1245 tnode_t *cn = build_constant(tn->tn_type, v); 1246 if (tn->u.ops.left->tn_system_dependent) 1247 cn->tn_system_dependent = true; 1248 if (is_binary(tn) && tn->u.ops.right->tn_system_dependent) 1249 cn->tn_system_dependent = true; 1250 1251 return cn; 1252 } 1253 1254 static tnode_t * 1255 build_struct_access(op_t op, bool sys, tnode_t *ln, tnode_t *rn) 1256 { 1257 1258 lint_assert(rn->tn_op == NAME); 1259 lint_assert(is_member(rn->u.sym)); 1260 1261 bool lvalue = op == ARROW || ln->tn_lvalue; 1262 1263 if (op == POINT) 1264 ln = build_address(sys, ln, true); 1265 else if (ln->tn_type->t_tspec != PTR) { 1266 lint_assert(!allow_c90); 1267 lint_assert(is_integer(ln->tn_type->t_tspec)); 1268 ln = convert(NOOP, 0, expr_derive_type(gettyp(VOID), PTR), ln); 1269 } 1270 1271 tnode_t *ctn = build_integer_constant(PTRDIFF_TSPEC, 1272 rn->u.sym->u.s_member.sm_offset_in_bits / CHAR_SIZE); 1273 1274 type_t *ptr_tp = expr_derive_type(rn->tn_type, PTR); 1275 tnode_t *ntn = build_op(PLUS, sys, ptr_tp, ln, ctn); 1276 if (ln->tn_op == CON) 1277 ntn = fold_constant_integer(ntn); 1278 1279 op_t nop = rn->tn_type->t_bitfield ? FSEL : INDIR; 1280 ntn = build_op(nop, sys, ntn->tn_type->t_subt, ntn, NULL); 1281 if (!lvalue) 1282 ntn->tn_lvalue = false; 1283 1284 return ntn; 1285 } 1286 1287 /* 1288 * Get the size in bytes of type tp->t_subt, as a constant expression of type 1289 * ptrdiff_t as seen from the target platform. 1290 */ 1291 static tnode_t * 1292 subt_size_in_bytes(type_t *tp) 1293 { 1294 1295 lint_assert(tp->t_tspec == PTR); 1296 tp = tp->t_subt; 1297 1298 int elem = 1; 1299 while (tp->t_tspec == ARRAY) { 1300 elem *= tp->u.dimension; 1301 tp = tp->t_subt; 1302 } 1303 1304 int elsz_in_bits = 0; 1305 switch (tp->t_tspec) { 1306 case FUNC: 1307 /* pointer to function is not allowed here */ 1308 error(110); 1309 break; 1310 case VOID: 1311 /* cannot do pointer arithmetic on operand of unknown size */ 1312 gnuism(136); 1313 break; 1314 case STRUCT: 1315 case UNION: 1316 if ((elsz_in_bits = (int)tp->u.sou->sou_size_in_bits) == 0) 1317 /* cannot do pointer arithmetic on operand of ... */ 1318 error(136); 1319 break; 1320 case ENUM: 1321 if (is_incomplete(tp)) 1322 /* cannot do pointer arithmetic on operand of ... */ 1323 warning(136); 1324 /* FALLTHROUGH */ 1325 default: 1326 if ((elsz_in_bits = size_in_bits(tp->t_tspec)) == 0) 1327 /* cannot do pointer arithmetic on operand of ... */ 1328 error(136); 1329 else 1330 lint_assert(elsz_in_bits != -1); 1331 break; 1332 } 1333 1334 if (elem == 0 && elsz_in_bits != 0) 1335 /* cannot do pointer arithmetic on operand of unknown size */ 1336 error(136); 1337 1338 if (elsz_in_bits == 0) 1339 elsz_in_bits = CHAR_SIZE; 1340 1341 return build_integer_constant(PTRDIFF_TSPEC, 1342 (int64_t)(elem * elsz_in_bits / CHAR_SIZE)); 1343 } 1344 1345 static tnode_t * 1346 build_prepost_incdec(op_t op, bool sys, tnode_t *ln) 1347 { 1348 1349 lint_assert(ln != NULL); 1350 tnode_t *cn = ln->tn_type->t_tspec == PTR 1351 ? subt_size_in_bytes(ln->tn_type) 1352 : build_integer_constant(INT, 1); 1353 return build_op(op, sys, ln->tn_type, ln, cn); 1354 } 1355 1356 static void 1357 check_enum_array_index(const tnode_t *ln, const tnode_t *rn) 1358 { 1359 1360 if (ln->tn_op != ADDR || ln->u.ops.left->tn_op != NAME) 1361 return; 1362 1363 const type_t *ltp = ln->u.ops.left->tn_type; 1364 if (ltp->t_tspec != ARRAY || ltp->t_incomplete_array) 1365 return; 1366 1367 if (rn->tn_op != CVT || !rn->tn_type->t_is_enum) 1368 return; 1369 if (rn->u.ops.left->tn_op != LOAD) 1370 return; 1371 1372 const type_t *rtp = rn->u.ops.left->tn_type; 1373 const sym_t *ec = rtp->u.enumer->en_first_enumerator; 1374 const sym_t *max_ec = ec; 1375 lint_assert(ec != NULL); 1376 for (ec = ec->s_next; ec != NULL; ec = ec->s_next) 1377 if (ec->u.s_enum_constant > max_ec->u.s_enum_constant) 1378 max_ec = ec; 1379 1380 int64_t max_enum_value = max_ec->u.s_enum_constant; 1381 lint_assert(INT_MIN <= max_enum_value && max_enum_value <= INT_MAX); 1382 1383 int max_array_index = ltp->u.dimension - 1; 1384 if (max_enum_value == max_array_index) 1385 return; 1386 1387 if (max_enum_value == max_array_index + 1 && 1388 (strstr(max_ec->s_name, "MAX") != NULL || 1389 strstr(max_ec->s_name, "max") != NULL || 1390 strstr(max_ec->s_name, "NUM") != NULL || 1391 strstr(max_ec->s_name, "num") != NULL || 1392 strncmp(max_ec->s_name, "N_", 2) == 0)) 1393 return; 1394 1395 /* maximum value %d for '%s' of type '%s' does not match maximum array index %d */ 1396 warning(348, (int)max_enum_value, max_ec->s_name, type_name(rtp), 1397 max_array_index); 1398 print_previous_declaration(max_ec); 1399 } 1400 1401 static tnode_t * 1402 build_plus_minus(op_t op, bool sys, tnode_t *ln, tnode_t *rn) 1403 { 1404 1405 if (rn->tn_type->t_tspec == PTR && is_integer(ln->tn_type->t_tspec)) { 1406 tnode_t *tmp = ln; 1407 ln = rn; 1408 rn = tmp; 1409 /* pointer addition has integer on the left-hand side */ 1410 query_message(5); 1411 } 1412 1413 /* pointer +- integer */ 1414 tspec_t lt = ln->tn_type->t_tspec; 1415 tspec_t rt = rn->tn_type->t_tspec; 1416 if (lt == PTR && rt != PTR) { 1417 lint_assert(is_integer(rt)); 1418 1419 check_ctype_macro_invocation(ln, rn); 1420 check_enum_array_index(ln, rn); 1421 1422 tnode_t *elsz = subt_size_in_bytes(ln->tn_type); 1423 tspec_t szt = elsz->tn_type->t_tspec; 1424 if (rt != szt && rt != unsigned_type(szt)) 1425 rn = convert(NOOP, 0, elsz->tn_type, rn); 1426 1427 tnode_t *prod = build_op(MULT, sys, rn->tn_type, rn, elsz); 1428 if (rn->tn_op == CON) 1429 prod = fold_constant_integer(prod); 1430 1431 return build_op(op, sys, ln->tn_type, ln, prod); 1432 } 1433 1434 /* pointer - pointer */ 1435 if (rt == PTR) { 1436 lint_assert(lt == PTR); 1437 lint_assert(op == MINUS); 1438 1439 type_t *ptrdiff = gettyp(PTRDIFF_TSPEC); 1440 tnode_t *raw_diff = build_op(op, sys, ptrdiff, ln, rn); 1441 if (ln->tn_op == CON && rn->tn_op == CON) 1442 raw_diff = fold_constant_integer(raw_diff); 1443 1444 tnode_t *elsz = subt_size_in_bytes(ln->tn_type); 1445 balance(NOOP, &raw_diff, &elsz); 1446 1447 return build_op(DIV, sys, ptrdiff, raw_diff, elsz); 1448 } 1449 1450 return build_op(op, sys, ln->tn_type, ln, rn); 1451 } 1452 1453 static tnode_t * 1454 build_bit_shift(op_t op, bool sys, tnode_t *ln, tnode_t *rn) 1455 { 1456 1457 if (!allow_c90 && rn->tn_type->t_tspec != INT) 1458 // XXX: C1978 7.5 says: "Both [operators] perform the usual 1459 // arithmetic conversions on their operands." 1460 // TODO: Add a test to exercise this part of the code. 1461 rn = convert(NOOP, 0, gettyp(INT), rn); 1462 return build_op(op, sys, ln->tn_type, ln, rn); 1463 } 1464 1465 static bool 1466 is_null_pointer(const tnode_t *tn) 1467 { 1468 tspec_t t = tn->tn_type->t_tspec; 1469 1470 // TODO: Investigate how other pointers are stored, in particular, 1471 // whether a pointer constant can have a non-zero value. 1472 // If not, simplify the code below. 1473 return ((t == PTR && tn->tn_type->t_subt->t_tspec == VOID) 1474 || is_integer(t)) 1475 && (tn->tn_op == CON && tn->u.value.u.integer == 0); 1476 } 1477 1478 /* Return a type based on tp1, with added qualifiers from tp2. */ 1479 static type_t * 1480 merge_qualifiers(type_t *tp1, const type_t *tp2) 1481 { 1482 1483 lint_assert(tp1->t_tspec == PTR); 1484 lint_assert(tp2->t_tspec == PTR); 1485 1486 bool c1 = tp1->t_subt->t_const; 1487 bool c2 = tp2->t_subt->t_const; 1488 bool v1 = tp1->t_subt->t_volatile; 1489 bool v2 = tp2->t_subt->t_volatile; 1490 1491 if (c1 == (c1 | c2) && v1 == (v1 | v2)) 1492 return tp1; 1493 1494 type_t *nstp = expr_dup_type(tp1->t_subt); 1495 nstp->t_const |= c2; 1496 nstp->t_volatile |= v2; 1497 1498 type_t *ntp = expr_dup_type(tp1); 1499 ntp->t_subt = nstp; 1500 return ntp; 1501 } 1502 1503 /* See C99 6.5.15 "Conditional operator". */ 1504 static tnode_t * 1505 build_colon(bool sys, tnode_t *ln, tnode_t *rn) 1506 { 1507 tspec_t lt = ln->tn_type->t_tspec; 1508 tspec_t rt = rn->tn_type->t_tspec; 1509 1510 type_t *tp; 1511 if (is_arithmetic(lt) && is_arithmetic(rt)) 1512 /* The operands were already balanced in build_binary. */ 1513 tp = ln->tn_type; 1514 else if (lt == BOOL && rt == BOOL) 1515 tp = ln->tn_type; 1516 else if (lt == VOID || rt == VOID) 1517 tp = gettyp(VOID); 1518 else if (is_struct_or_union(lt)) { 1519 lint_assert(is_struct_or_union(rt)); 1520 lint_assert(ln->tn_type->u.sou == rn->tn_type->u.sou); 1521 if (is_incomplete(ln->tn_type)) { 1522 /* unknown operand size, op '%s' */ 1523 error(138, op_name(COLON)); 1524 return NULL; 1525 } 1526 tp = ln->tn_type; 1527 } else if (lt == PTR && is_integer(rt)) { 1528 if (rt != PTRDIFF_TSPEC) 1529 rn = convert(NOOP, 0, gettyp(PTRDIFF_TSPEC), rn); 1530 tp = ln->tn_type; 1531 } else if (rt == PTR && is_integer(lt)) { 1532 if (lt != PTRDIFF_TSPEC) 1533 ln = convert(NOOP, 0, gettyp(PTRDIFF_TSPEC), ln); 1534 tp = rn->tn_type; 1535 } else if (lt == PTR && is_null_pointer(rn)) 1536 tp = merge_qualifiers(ln->tn_type, rn->tn_type); 1537 else if (rt == PTR && is_null_pointer(ln)) 1538 tp = merge_qualifiers(rn->tn_type, ln->tn_type); 1539 else if (lt == PTR && ln->tn_type->t_subt->t_tspec == VOID) 1540 tp = merge_qualifiers(ln->tn_type, rn->tn_type); 1541 else if (rt == PTR && rn->tn_type->t_subt->t_tspec == VOID) 1542 tp = merge_qualifiers(rn->tn_type, ln->tn_type); 1543 else { 1544 /* 1545 * XXX For now we simply take the left type. This is probably 1546 * wrong, if one type contains a function prototype and the 1547 * other one, at the same place, only an old-style declaration. 1548 */ 1549 tp = merge_qualifiers(ln->tn_type, rn->tn_type); 1550 } 1551 1552 return build_op(COLON, sys, tp, ln, rn); 1553 } 1554 1555 /* TODO: check for varargs */ 1556 static bool 1557 is_cast_redundant(const tnode_t *tn) 1558 { 1559 const type_t *ntp = tn->tn_type, *otp = tn->u.ops.left->tn_type; 1560 tspec_t nt = ntp->t_tspec, ot = otp->t_tspec; 1561 1562 if (nt == BOOL || ot == BOOL) 1563 return nt == BOOL && ot == BOOL; 1564 1565 if (is_integer(nt) && is_integer(ot)) { 1566 unsigned int nw = width_in_bits(ntp), ow = width_in_bits(otp); 1567 if (is_uinteger(nt) == is_uinteger(ot)) 1568 return nw >= ow; 1569 return is_uinteger(ot) && nw > ow; 1570 } 1571 1572 if (is_complex(nt) || is_complex(ot)) 1573 return is_complex(nt) && is_complex(ot) && 1574 size_in_bits(nt) >= size_in_bits(ot); 1575 1576 if (is_floating(nt) && is_floating(ot)) 1577 return size_in_bits(nt) >= size_in_bits(ot); 1578 1579 if (nt == PTR && ot == PTR) { 1580 if (!ntp->t_subt->t_const && otp->t_subt->t_const) 1581 return false; 1582 if (!ntp->t_subt->t_volatile && otp->t_subt->t_volatile) 1583 return false; 1584 1585 if (ntp->t_subt->t_tspec == VOID || 1586 otp->t_subt->t_tspec == VOID || 1587 types_compatible(ntp->t_subt, otp->t_subt, 1588 false, false, NULL)) 1589 return true; 1590 } 1591 1592 return false; 1593 } 1594 1595 static bool 1596 is_assignment(op_t op) 1597 { 1598 1599 return op == ASSIGN || 1600 op == MULASS || 1601 op == DIVASS || 1602 op == MODASS || 1603 op == ADDASS || 1604 op == SUBASS || 1605 op == SHLASS || 1606 op == SHRASS || 1607 op == ANDASS || 1608 op == XORASS || 1609 op == ORASS || 1610 op == RETURN || 1611 op == INIT; 1612 } 1613 1614 static tnode_t * 1615 build_assignment(op_t op, bool sys, tnode_t *ln, tnode_t *rn) 1616 { 1617 1618 tspec_t lt = ln->tn_type->t_tspec; 1619 tspec_t rt = rn->tn_type->t_tspec; 1620 1621 if (is_assignment(rn->tn_op)) 1622 /* chained assignment with '%s' and '%s' */ 1623 query_message(10, op_name(op), op_name(rn->tn_op)); 1624 1625 if ((op == ADDASS || op == SUBASS) && lt == PTR) { 1626 lint_assert(is_integer(rt)); 1627 tnode_t *ctn = subt_size_in_bytes(ln->tn_type); 1628 if (rn->tn_type->t_tspec != ctn->tn_type->t_tspec) 1629 rn = convert(NOOP, 0, ctn->tn_type, rn); 1630 rn = build_op(MULT, sys, rn->tn_type, rn, ctn); 1631 if (rn->u.ops.left->tn_op == CON) 1632 rn = fold_constant_integer(rn); 1633 } 1634 1635 if ((op == ASSIGN || op == RETURN || op == INIT) && 1636 (lt == STRUCT || rt == STRUCT)) { 1637 lint_assert(lt == rt); 1638 lint_assert(ln->tn_type->u.sou == rn->tn_type->u.sou); 1639 if (is_incomplete(ln->tn_type)) { 1640 if (op == RETURN) 1641 /* cannot return incomplete type */ 1642 error(212); 1643 else 1644 /* unknown operand size, op '%s' */ 1645 error(138, op_name(op)); 1646 return NULL; 1647 } 1648 } 1649 1650 if (op == SHLASS && hflag && allow_trad && allow_c90 1651 && portable_rank_cmp(lt, rt) < 0) 1652 /* semantics of '%s' change in C90; ... */ 1653 warning(118, "<<="); 1654 1655 if (op != SHLASS && op != SHRASS 1656 && (op == ASSIGN || lt != PTR) 1657 && (lt != rt || (ln->tn_type->t_bitfield && rn->tn_op == CON))) { 1658 rn = convert(op, 0, ln->tn_type, rn); 1659 rt = lt; 1660 } 1661 1662 if (lt == PTR && ln->tn_type->t_subt->t_tspec != VOID 1663 && rt == PTR && rn->tn_type->t_subt->t_tspec == VOID 1664 && !is_null_pointer(rn)) 1665 /* implicit narrowing conversion from void ... */ 1666 query_message(20, type_name(ln->tn_type)); 1667 1668 if (any_query_enabled && rn->tn_op == CVT && rn->tn_cast && 1669 types_compatible(ln->tn_type, rn->tn_type, false, false, NULL) && 1670 is_cast_redundant(rn)) { 1671 /* redundant cast from '%s' to '%s' before assignment */ 1672 query_message(7, type_name(rn->u.ops.left->tn_type), 1673 type_name(rn->tn_type)); 1674 } 1675 1676 return build_op(op, sys, ln->tn_type, ln, rn); 1677 } 1678 1679 static tnode_t * 1680 build_real_imag(op_t op, bool sys, tnode_t *ln) 1681 { 1682 1683 lint_assert(ln != NULL); 1684 if (ln->tn_op == NAME) { 1685 /* 1686 * This may be too much, but it avoids wrong warnings. See 1687 * d_c99_complex_split.c. 1688 */ 1689 mark_as_used(ln->u.sym, false, false); 1690 mark_as_set(ln->u.sym); 1691 } 1692 1693 tspec_t t; 1694 switch (ln->tn_type->t_tspec) { 1695 case LCOMPLEX: 1696 t = LDOUBLE; 1697 break; 1698 case DCOMPLEX: 1699 t = DOUBLE; 1700 break; 1701 case FCOMPLEX: 1702 t = FLOAT; 1703 break; 1704 default: 1705 /* '__%s__' is illegal for type '%s' */ 1706 error(276, op == REAL ? "real" : "imag", 1707 type_name(ln->tn_type)); 1708 return NULL; 1709 } 1710 1711 tnode_t *ntn = build_op(op, sys, gettyp(t), ln, NULL); 1712 ntn->tn_lvalue = true; 1713 return ntn; 1714 } 1715 1716 static bool 1717 is_confusing_precedence(op_t op, const tnode_t *operand, op_t *cop) 1718 { 1719 if (operand->tn_parenthesized) 1720 return false; 1721 op_t oop = operand->tn_op; 1722 1723 if (op == SHL || op == SHR) { 1724 if (oop == PLUS || oop == MINUS) 1725 return *cop = oop, true; 1726 return false; 1727 } 1728 1729 if (op == LOGOR) { 1730 if (oop == LOGAND) 1731 return *cop = oop, true; 1732 return false; 1733 } 1734 1735 lint_assert(op == BITAND || op == BITXOR || op == BITOR); 1736 if (oop != op 1737 && (oop == PLUS || oop == MINUS || oop == BITAND || oop == BITXOR)) 1738 return *cop = oop, true; 1739 return false; 1740 } 1741 1742 /* 1743 * Print a warning if the given node has operands which should be 1744 * parenthesized. 1745 * 1746 * XXX Does not work if an operand is a constant expression. Constant 1747 * expressions are already folded. 1748 */ 1749 static void 1750 check_precedence_confusion(tnode_t *tn) 1751 { 1752 tnode_t *ln, *rn; 1753 1754 if (!hflag) 1755 return; 1756 1757 debug_node(tn); 1758 1759 lint_assert(is_binary(tn)); 1760 for (ln = tn->u.ops.left; ln->tn_op == CVT; ln = ln->u.ops.left) 1761 continue; 1762 for (rn = tn->u.ops.right; rn->tn_op == CVT; rn = rn->u.ops.left) 1763 continue; 1764 1765 op_t cop; 1766 if (is_confusing_precedence(tn->tn_op, ln, &cop) || 1767 is_confusing_precedence(tn->tn_op, rn, &cop)) { 1768 /* possible precedence confusion between '%s' and '%s' */ 1769 warning(169, op_name(tn->tn_op), op_name(cop)); 1770 } 1771 } 1772 1773 static tnode_t * 1774 fold_constant_compare_zero(tnode_t *tn) 1775 { 1776 1777 val_t *v = xcalloc(1, sizeof(*v)); 1778 v->v_tspec = tn->tn_type->t_tspec; 1779 lint_assert(v->v_tspec == INT || (Tflag && v->v_tspec == BOOL)); 1780 1781 lint_assert(has_operands(tn)); 1782 bool l = constant_is_nonzero(tn->u.ops.left); 1783 bool r = is_binary(tn) && constant_is_nonzero(tn->u.ops.right); 1784 1785 switch (tn->tn_op) { 1786 case NOT: 1787 if (hflag && !suppress_constcond) 1788 /* constant operand to '!' */ 1789 warning(239); 1790 v->u.integer = !l ? 1 : 0; 1791 break; 1792 case LOGAND: 1793 v->u.integer = l && r ? 1 : 0; 1794 break; 1795 case LOGOR: 1796 v->u.integer = l || r ? 1 : 0; 1797 break; 1798 default: 1799 lint_assert(/*CONSTCOND*/false); 1800 } 1801 1802 return build_constant(tn->tn_type, v); 1803 } 1804 1805 static long double 1806 floating_error_value(tspec_t t, long double lv) 1807 { 1808 if (t == FLOAT) 1809 return lv < 0 ? -FLT_MAX : FLT_MAX; 1810 if (t == DOUBLE) 1811 return lv < 0 ? -DBL_MAX : DBL_MAX; 1812 /* 1813 * When NetBSD is cross-built in MKLINT=yes mode on x86_64 for sparc64, 1814 * tools/lint checks this code while building usr.bin/xlint. In that 1815 * situation, lint uses the preprocessor for sparc64, in which the type 1816 * 'long double' is IEEE-754-binary128, affecting the macro LDBL_MAX 1817 * below. The type 'long double', as well as the strtold 1818 * implementation, comes from the host platform x86_64 though, where 1819 * 'long double' consumes 128 bits as well but only uses 80 of them. 1820 * The exponent range of the two 'long double' types is the same, but 1821 * the maximum finite value differs due to the extended precision on 1822 * sparc64. 1823 * 1824 * To properly handle the data types of the target platform, lint would 1825 * have to implement the floating-point types in a platform-independent 1826 * way, which is not worth the effort, given how few programs 1827 * practically use 'long double'. 1828 */ 1829 /* LINTED 248: floating-point constant out of range */ 1830 long double max = LDBL_MAX; 1831 return lv < 0 ? -max : max; 1832 } 1833 1834 static bool 1835 is_floating_overflow(tspec_t t, long double val) 1836 { 1837 if (fpe != 0 || isfinite(val) == 0) 1838 return true; 1839 if (t == FLOAT && (val > FLT_MAX || val < -FLT_MAX)) 1840 return true; 1841 if (t == DOUBLE && (val > DBL_MAX || val < -DBL_MAX)) 1842 return true; 1843 return false; 1844 } 1845 1846 static tnode_t * 1847 fold_constant_floating(tnode_t *tn) 1848 { 1849 1850 fpe = 0; 1851 1852 tspec_t t = tn->tn_type->t_tspec; 1853 1854 val_t *v = xcalloc(1, sizeof(*v)); 1855 v->v_tspec = t; 1856 1857 lint_assert(is_floating(t)); 1858 lint_assert(has_operands(tn)); 1859 lint_assert(t == tn->u.ops.left->tn_type->t_tspec); 1860 lint_assert(!is_binary(tn) || t == tn->u.ops.right->tn_type->t_tspec); 1861 1862 long double lv = tn->u.ops.left->u.value.u.floating; 1863 long double rv = is_binary(tn) ? tn->u.ops.right->u.value.u.floating 1864 : 0.0; 1865 1866 switch (tn->tn_op) { 1867 case UPLUS: 1868 v->u.floating = lv; 1869 break; 1870 case UMINUS: 1871 v->u.floating = -lv; 1872 break; 1873 case MULT: 1874 v->u.floating = lv * rv; 1875 break; 1876 case DIV: 1877 if (rv == 0.0) { 1878 /* division by 0 */ 1879 error(139); 1880 v->u.floating = floating_error_value(t, lv); 1881 } else { 1882 v->u.floating = lv / rv; 1883 } 1884 break; 1885 case PLUS: 1886 v->u.floating = lv + rv; 1887 break; 1888 case MINUS: 1889 v->u.floating = lv - rv; 1890 break; 1891 case LT: 1892 v->u.integer = lv < rv ? 1 : 0; 1893 break; 1894 case LE: 1895 v->u.integer = lv <= rv ? 1 : 0; 1896 break; 1897 case GE: 1898 v->u.integer = lv >= rv ? 1 : 0; 1899 break; 1900 case GT: 1901 v->u.integer = lv > rv ? 1 : 0; 1902 break; 1903 case EQ: 1904 v->u.integer = lv == rv ? 1 : 0; 1905 break; 1906 case NE: 1907 v->u.integer = lv != rv ? 1 : 0; 1908 break; 1909 default: 1910 lint_assert(/*CONSTCOND*/false); 1911 } 1912 1913 // XXX: Must not access u.floating after setting u.integer. 1914 lint_assert(fpe != 0 || isnan(v->u.floating) == 0); 1915 if (is_complex(v->v_tspec)) { 1916 /* 1917 * Don't warn, as lint doesn't model the imaginary part of 1918 * complex numbers. 1919 */ 1920 fpe = 0; 1921 } else if (is_floating_overflow(t, v->u.floating)) { 1922 /* operator '%s' produces floating point overflow */ 1923 warning(142, op_name(tn->tn_op)); 1924 v->u.floating = floating_error_value(t, v->u.floating); 1925 fpe = 0; 1926 } 1927 1928 return build_constant(tn->tn_type, v); 1929 } 1930 1931 static void 1932 use(const tnode_t *tn) 1933 { 1934 if (tn == NULL) 1935 return; 1936 switch (tn->tn_op) { 1937 case NAME: 1938 mark_as_used(tn->u.sym, false /* XXX */, false /* XXX */); 1939 break; 1940 case CON: 1941 case STRING: 1942 break; 1943 case CALL:; 1944 const function_call *call = tn->u.call; 1945 for (size_t i = 0, n = call->args_len; i < n; i++) 1946 use(call->args[i]); 1947 break; 1948 default: 1949 lint_assert(has_operands(tn)); 1950 use(tn->u.ops.left); 1951 if (is_binary(tn)) 1952 use(tn->u.ops.right); 1953 } 1954 } 1955 1956 /* 1957 * Create a tree node for a binary operator and its two operands. Also called 1958 * for unary operators; in that case rn is NULL. 1959 * 1960 * Function calls, sizeof and casts are handled elsewhere. 1961 */ 1962 tnode_t * 1963 build_binary(tnode_t *ln, op_t op, bool sys, tnode_t *rn) 1964 { 1965 const mod_t *mp = &modtab[op]; 1966 1967 /* If there was an error in one of the operands, return. */ 1968 if (ln == NULL || (mp->m_binary && rn == NULL)) 1969 return NULL; 1970 1971 if (mp->m_value_context || mp->m_compares_with_zero) 1972 ln = cconv(ln); 1973 if (mp->m_binary && op != ARROW && op != POINT) 1974 rn = cconv(rn); 1975 1976 if (mp->m_comparison) 1977 check_integer_comparison(op, ln, rn); 1978 1979 if (mp->m_value_context || mp->m_compares_with_zero) 1980 ln = promote(op, false, ln); 1981 if (mp->m_binary && op != ARROW && op != POINT && 1982 op != ASSIGN && op != RETURN && op != INIT) 1983 rn = promote(op, false, rn); 1984 1985 if (mp->m_warn_if_left_unsigned_in_c90 && 1986 ln->tn_op == CON && ln->u.value.v_unsigned_since_c90) { 1987 /* C90 treats constant as unsigned, op '%s' */ 1988 warning(218, op_name(op)); 1989 ln->u.value.v_unsigned_since_c90 = false; 1990 } 1991 if (mp->m_warn_if_right_unsigned_in_c90 && 1992 rn->tn_op == CON && rn->u.value.v_unsigned_since_c90) { 1993 /* C90 treats constant as unsigned, op '%s' */ 1994 warning(218, op_name(op)); 1995 rn->u.value.v_unsigned_since_c90 = false; 1996 } 1997 1998 if (mp->m_balance_operands || (!allow_c90 && (op == SHL || op == SHR))) 1999 balance(op, &ln, &rn); 2000 2001 if (!typeok(op, 0, ln, rn)) 2002 return NULL; 2003 2004 tnode_t *ntn; 2005 switch (op) { 2006 case POINT: 2007 case ARROW: 2008 ntn = build_struct_access(op, sys, ln, rn); 2009 break; 2010 case NOT: 2011 if (ln->tn_op == ASSIGN && ln->u.ops.right->tn_op == CON) { 2012 /* constant assignment of type '%s' in operand ... */ 2013 warning(382, type_name(ln->tn_type), 2014 is_nonzero_val(&ln->u.ops.right->u.value) 2015 ? "true" : "false"); 2016 } 2017 ntn = build_op(op, sys, gettyp(Tflag ? BOOL : INT), ln, NULL); 2018 break; 2019 case INCAFT: 2020 case DECAFT: 2021 case INCBEF: 2022 case DECBEF: 2023 ntn = build_prepost_incdec(op, sys, ln); 2024 break; 2025 case ADDR: 2026 ntn = build_address(sys, ln, false); 2027 break; 2028 case INDIR: 2029 ntn = build_op(INDIR, sys, ln->tn_type->t_subt, ln, NULL); 2030 break; 2031 case PLUS: 2032 case MINUS: 2033 ntn = build_plus_minus(op, sys, ln, rn); 2034 break; 2035 case SHL: 2036 case SHR: 2037 ntn = build_bit_shift(op, sys, ln, rn); 2038 break; 2039 case COLON: 2040 ntn = build_colon(sys, ln, rn); 2041 break; 2042 case ASSIGN: 2043 case MULASS: 2044 case DIVASS: 2045 case MODASS: 2046 case ADDASS: 2047 case SUBASS: 2048 case SHLASS: 2049 case SHRASS: 2050 case ANDASS: 2051 case XORASS: 2052 case ORASS: 2053 case RETURN: 2054 case INIT: 2055 ntn = build_assignment(op, sys, ln, rn); 2056 break; 2057 case COMMA: 2058 /* comma operator with types '%s' and '%s' */ 2059 query_message(12, 2060 type_name(ln->tn_type), type_name(rn->tn_type)); 2061 /* FALLTHROUGH */ 2062 case QUEST: 2063 ntn = build_op(op, sys, rn->tn_type, ln, rn); 2064 break; 2065 case REAL: 2066 case IMAG: 2067 ntn = build_real_imag(op, sys, ln); 2068 break; 2069 default: 2070 lint_assert(mp->m_binary == (rn != NULL)); 2071 type_t *rettp = mp->m_returns_bool 2072 ? gettyp(Tflag ? BOOL : INT) : ln->tn_type; 2073 ntn = build_op(op, sys, rettp, ln, rn); 2074 break; 2075 } 2076 2077 if (ntn == NULL) 2078 return NULL; 2079 2080 if (mp->m_possible_precedence_confusion) 2081 check_precedence_confusion(ntn); 2082 2083 if (hflag && !suppress_constcond && 2084 mp->m_compares_with_zero && 2085 (ln->tn_op == CON || 2086 (mp->m_binary && op != QUEST && rn->tn_op == CON)) && 2087 /* XXX: rn->tn_system_dependent should be checked as well */ 2088 !ln->tn_system_dependent) 2089 /* constant in conditional context */ 2090 warning(161); 2091 2092 if (mp->m_fold_constant_operands && ln->tn_op == CON) { 2093 if (!mp->m_binary || rn->tn_op == CON) { 2094 if (mp->m_compares_with_zero) 2095 ntn = fold_constant_compare_zero(ntn); 2096 else if (is_floating(ntn->tn_type->t_tspec)) 2097 ntn = fold_constant_floating(ntn); 2098 else 2099 ntn = fold_constant_integer(ntn); 2100 } else if (op == QUEST) { 2101 lint_assert(has_operands(rn)); 2102 use(ln->u.value.u.integer != 0 2103 ? rn->u.ops.right : rn->u.ops.left); 2104 ntn = ln->u.value.u.integer != 0 2105 ? rn->u.ops.left : rn->u.ops.right; 2106 } 2107 } 2108 2109 return ntn; 2110 } 2111 2112 tnode_t * 2113 build_unary(op_t op, bool sys, tnode_t *tn) 2114 { 2115 return build_binary(tn, op, sys, NULL); 2116 } 2117 2118 static bool 2119 are_members_compatible(const sym_t *a, const sym_t *b) 2120 { 2121 if (a->u.s_member.sm_offset_in_bits != b->u.s_member.sm_offset_in_bits) 2122 return false; 2123 2124 const type_t *atp = a->s_type; 2125 const type_t *btp = b->s_type; 2126 bool w = false; 2127 if (!types_compatible(atp, btp, false, false, &w) && !w) 2128 return false; 2129 if (a->s_bitfield != b->s_bitfield) 2130 return false; 2131 if (a->s_bitfield) { 2132 if (atp->t_bit_field_width != btp->t_bit_field_width) 2133 return false; 2134 if (atp->t_bit_field_offset != btp->t_bit_field_offset) 2135 return false; 2136 } 2137 return true; 2138 } 2139 2140 /* 2141 * Return whether all struct/union members with the same name have the same 2142 * type and offset. 2143 */ 2144 static bool 2145 all_members_compatible(const sym_t *msym) 2146 { 2147 for (const sym_t *csym = msym; 2148 csym != NULL; csym = csym->s_symtab_next) { 2149 if (!is_member(csym)) 2150 continue; 2151 if (strcmp(msym->s_name, csym->s_name) != 0) 2152 continue; 2153 2154 for (const sym_t *sym = csym->s_symtab_next; 2155 sym != NULL; sym = sym->s_symtab_next) { 2156 if (is_member(sym) 2157 && strcmp(csym->s_name, sym->s_name) == 0 2158 && !are_members_compatible(csym, sym)) 2159 return false; 2160 } 2161 } 2162 return true; 2163 } 2164 2165 sym_t * 2166 find_member(const struct_or_union *sou, const char *name) 2167 { 2168 for (sym_t *mem = sou->sou_first_member; 2169 mem != NULL; mem = mem->s_next) { 2170 lint_assert(is_member(mem)); 2171 lint_assert(mem->u.s_member.sm_containing_type == sou); 2172 if (strcmp(mem->s_name, name) == 0) 2173 return mem; 2174 } 2175 2176 for (sym_t *mem = sou->sou_first_member; 2177 mem != NULL; mem = mem->s_next) { 2178 if (is_struct_or_union(mem->s_type->t_tspec) 2179 && mem->s_name == unnamed) { 2180 sym_t *nested_mem = 2181 find_member(mem->s_type->u.sou, name); 2182 if (nested_mem != NULL) 2183 return nested_mem; 2184 } 2185 } 2186 return NULL; 2187 } 2188 2189 /* 2190 * Remove the member if it was unknown until now, which means 2191 * that no defined struct or union has a member with the same name. 2192 */ 2193 static void 2194 remove_unknown_member(tnode_t *tn, sym_t *msym) 2195 { 2196 /* type '%s' does not have member '%s' */ 2197 error(101, type_name(tn->tn_type), msym->s_name); 2198 symtab_remove_forever(msym); 2199 msym->s_kind = SK_MEMBER; 2200 msym->s_scl = STRUCT_MEMBER; 2201 2202 struct_or_union *sou = expr_zero_alloc(sizeof(*sou), 2203 "struct_or_union"); 2204 sou->sou_tag = expr_zero_alloc(sizeof(*sou->sou_tag), "sym"); 2205 sou->sou_tag->s_name = unnamed; 2206 2207 msym->u.s_member.sm_containing_type = sou; 2208 /* 2209 * The member sm_offset_in_bits is not needed here since this symbol 2210 * can only be used for error reporting. 2211 */ 2212 } 2213 2214 /* 2215 * Returns a symbol which has the same name as 'msym' and is a member of the 2216 * struct or union specified by 'tn'. 2217 */ 2218 static sym_t * 2219 struct_or_union_member(tnode_t *tn, op_t op, sym_t *msym) 2220 { 2221 2222 /* Determine the tag type of which msym is expected to be a member. */ 2223 const type_t *tp = NULL; 2224 if (op == POINT && is_struct_or_union(tn->tn_type->t_tspec)) 2225 tp = tn->tn_type; 2226 if (op == ARROW && tn->tn_type->t_tspec == PTR 2227 && is_struct_or_union(tn->tn_type->t_subt->t_tspec)) 2228 tp = tn->tn_type->t_subt; 2229 struct_or_union *sou = tp != NULL ? tp->u.sou : NULL; 2230 2231 if (sou != NULL) { 2232 sym_t *nested_mem = find_member(sou, msym->s_name); 2233 if (nested_mem != NULL) 2234 return nested_mem; 2235 } 2236 2237 if (msym->s_scl == NO_SCL) { 2238 remove_unknown_member(tn, msym); 2239 return msym; 2240 } 2241 2242 bool eq = all_members_compatible(msym); 2243 2244 /* 2245 * Now handle the case in which the left operand refers really to a 2246 * struct/union, but the right operand is not member of it. 2247 */ 2248 if (sou != NULL) { 2249 if (eq && !allow_c90) 2250 /* illegal use of member '%s' */ 2251 warning(102, msym->s_name); 2252 else 2253 /* illegal use of member '%s' */ 2254 error(102, msym->s_name); 2255 return msym; 2256 } 2257 2258 if (eq) { 2259 if (op == POINT) { 2260 if (!allow_c90) 2261 /* left operand of '.' must be struct ... */ 2262 warning(103, type_name(tn->tn_type)); 2263 else 2264 /* left operand of '.' must be struct ... */ 2265 error(103, type_name(tn->tn_type)); 2266 } else { 2267 if (!allow_c90 && tn->tn_type->t_tspec == PTR) 2268 /* left operand of '->' must be pointer ... */ 2269 warning(104, type_name(tn->tn_type)); 2270 else 2271 /* left operand of '->' must be pointer ... */ 2272 error(104, type_name(tn->tn_type)); 2273 } 2274 } else { 2275 if (!allow_c90) 2276 /* non-unique member requires struct/union %s */ 2277 error(105, op == POINT ? "object" : "pointer"); 2278 else 2279 /* unacceptable operand of '%s' */ 2280 error(111, op_name(op)); 2281 } 2282 2283 return msym; 2284 } 2285 2286 tnode_t * 2287 build_member_access(tnode_t *ln, op_t op, bool sys, sbuf_t *member) 2288 { 2289 sym_t *msym; 2290 2291 if (ln == NULL) 2292 return NULL; 2293 2294 if (op == ARROW) 2295 /* must do this before struct_or_union_member is called */ 2296 ln = cconv(ln); 2297 msym = struct_or_union_member(ln, op, getsym(member)); 2298 return build_binary(ln, op, sys, build_name(msym, false)); 2299 } 2300 2301 /* 2302 * Perform class conversions. 2303 * 2304 * Arrays of type T are converted into pointers to type T. 2305 * Functions are converted to pointers to functions. 2306 * Lvalues are converted to rvalues. 2307 * 2308 * C99 6.3 "Conversions" 2309 * C99 6.3.2 "Other operands" 2310 * C99 6.3.2.1 "Lvalues, arrays, and function designators" 2311 */ 2312 tnode_t * 2313 cconv(tnode_t *tn) 2314 { 2315 if (tn->tn_type->t_tspec == ARRAY) { 2316 if (!tn->tn_lvalue) { 2317 /* XXX print correct operator */ 2318 /* %soperand of '%s' must be lvalue */ 2319 gnuism(114, "", op_name(ADDR)); 2320 } 2321 tn = build_op(ADDR, tn->tn_sys, 2322 expr_derive_type(tn->tn_type->t_subt, PTR), tn, NULL); 2323 } 2324 2325 if (tn->tn_type->t_tspec == FUNC) 2326 tn = build_address(tn->tn_sys, tn, true); 2327 2328 if (tn->tn_lvalue) { 2329 type_t *tp = expr_dup_type(tn->tn_type); 2330 /* C99 6.3.2.1p2 sentence 2 says to remove the qualifiers. */ 2331 tp->t_const = tp->t_volatile = false; 2332 tn = build_op(LOAD, tn->tn_sys, tp, tn, NULL); 2333 } 2334 2335 return tn; 2336 } 2337 2338 const tnode_t * 2339 before_conversion(const tnode_t *tn) 2340 { 2341 while (tn->tn_op == CVT && !tn->tn_cast) 2342 tn = tn->u.ops.left; 2343 return tn; 2344 } 2345 2346 /* 2347 * Most errors required by C90 are reported in struct_or_union_member(). 2348 * Here we only check for totally wrong things. 2349 */ 2350 static bool 2351 typeok_point(const tnode_t *ln, const type_t *ltp, tspec_t lt) 2352 { 2353 if (is_struct_or_union(lt)) 2354 return true; 2355 2356 if (lt == FUNC || lt == VOID || ltp->t_bitfield) 2357 goto wrong; 2358 2359 /* 2360 * Some C dialects from before C90 tolerated any lvalue on the 2361 * left-hand side of the '.' operator, allowing things like 'char 2362 * st[100]; st.st_mtime', assuming that the member 'st_mtime' only 2363 * occurred in a single struct; see typeok_arrow. 2364 */ 2365 if (ln->tn_lvalue) 2366 return true; 2367 2368 wrong: 2369 /* With allow_c90 we already got an error */ 2370 if (!allow_c90) 2371 /* unacceptable operand of '%s' */ 2372 error(111, op_name(POINT)); 2373 2374 return false; 2375 } 2376 2377 static bool 2378 typeok_arrow(tspec_t lt) 2379 { 2380 /* 2381 * C1978 Appendix A 14.1 says: <quote>In fact, any lvalue is allowed 2382 * before '.', and that lvalue is then assumed to have the form of the 2383 * structure of which the name of the right is a member. [...] Such 2384 * constructions are non-portable.</quote> 2385 */ 2386 if (lt == PTR || (!allow_c90 && is_integer(lt))) 2387 return true; 2388 2389 /* With allow_c90 we already got an error */ 2390 if (!allow_c90) 2391 /* unacceptable operand of '%s' */ 2392 error(111, op_name(ARROW)); 2393 return false; 2394 } 2395 2396 static bool 2397 typeok_incdec(op_t op, const tnode_t *tn, const type_t *tp) 2398 { 2399 /* operand has scalar type (checked in typeok) */ 2400 if (!tn->tn_lvalue) { 2401 if (tn->tn_op == CVT && tn->tn_cast && 2402 tn->u.ops.left->tn_op == LOAD) 2403 /* a cast does not yield an lvalue */ 2404 error(163); 2405 /* %soperand of '%s' must be lvalue */ 2406 error(114, "", op_name(op)); 2407 return false; 2408 } 2409 if (tp->t_const && allow_c90) 2410 /* %soperand of '%s' must be modifiable lvalue */ 2411 warning(115, "", op_name(op)); 2412 return true; 2413 } 2414 2415 static bool 2416 typeok_address(op_t op, const tnode_t *tn, const type_t *tp, tspec_t t) 2417 { 2418 if (t == ARRAY || t == FUNC) { 2419 /* ok, a warning comes later (in build_address()) */ 2420 } else if (!tn->tn_lvalue) { 2421 if (tn->tn_op == CVT && tn->tn_cast && 2422 tn->u.ops.left->tn_op == LOAD) 2423 /* a cast does not yield an lvalue */ 2424 error(163); 2425 /* %soperand of '%s' must be lvalue */ 2426 error(114, "", op_name(op)); 2427 return false; 2428 } else if (is_scalar(t)) { 2429 if (tp->t_bitfield) { 2430 /* cannot take address of bit-field */ 2431 error(112); 2432 return false; 2433 } 2434 } else if (t != STRUCT && t != UNION) { 2435 /* unacceptable operand of '%s' */ 2436 error(111, op_name(op)); 2437 return false; 2438 } 2439 if (tn->tn_op == NAME && tn->u.sym->s_register) { 2440 /* cannot take address of register '%s' */ 2441 error(113, tn->u.sym->s_name); 2442 return false; 2443 } 2444 return true; 2445 } 2446 2447 static bool 2448 typeok_indir(const type_t *tp, tspec_t t) 2449 { 2450 2451 if (t != PTR) { 2452 /* cannot dereference non-pointer type '%s' */ 2453 error(96, type_name(tp)); 2454 return false; 2455 } 2456 return true; 2457 } 2458 2459 static void 2460 warn_incompatible_types(op_t op, 2461 const type_t *ltp, tspec_t lt, 2462 const type_t *rtp, tspec_t rt) 2463 { 2464 bool binary = modtab[op].m_binary; 2465 2466 if (lt == VOID || (binary && rt == VOID)) { 2467 /* void type illegal in expression */ 2468 error(109); 2469 } else if (op == ASSIGN) 2470 /* cannot assign to '%s' from '%s' */ 2471 error(171, type_name(ltp), type_name(rtp)); 2472 else if (binary) 2473 /* operands of '%s' have incompatible types '%s' and '%s' */ 2474 error(107, op_name(op), type_name(ltp), type_name(rtp)); 2475 else { 2476 lint_assert(rt == NO_TSPEC); 2477 /* operand of '%s' has invalid type '%s' */ 2478 error(108, op_name(op), type_name(ltp)); 2479 } 2480 } 2481 2482 static bool 2483 typeok_plus(op_t op, 2484 const type_t *ltp, tspec_t lt, 2485 const type_t *rtp, tspec_t rt) 2486 { 2487 /* operands have scalar types (checked in typeok) */ 2488 if ((lt == PTR && !is_integer(rt)) || (rt == PTR && !is_integer(lt))) { 2489 warn_incompatible_types(op, ltp, lt, rtp, rt); 2490 return false; 2491 } 2492 return true; 2493 } 2494 2495 static bool 2496 typeok_minus(op_t op, 2497 const type_t *ltp, tspec_t lt, 2498 const type_t *rtp, tspec_t rt) 2499 { 2500 /* operands have scalar types (checked in typeok) */ 2501 if ((lt == PTR && rt != PTR && !is_integer(rt)) || 2502 (lt != PTR && rt == PTR)) { 2503 warn_incompatible_types(op, ltp, lt, rtp, rt); 2504 return false; 2505 } 2506 if (lt == PTR && rt == PTR && 2507 !types_compatible(ltp->t_subt, rtp->t_subt, true, false, NULL)) { 2508 /* illegal pointer subtraction */ 2509 error(116); 2510 } 2511 return true; 2512 } 2513 2514 static void 2515 typeok_shr(op_t op, 2516 const tnode_t *ln, tspec_t lt, 2517 const tnode_t *rn, tspec_t rt) 2518 { 2519 tspec_t olt = before_conversion(ln)->tn_type->t_tspec; 2520 tspec_t ort = before_conversion(rn)->tn_type->t_tspec; 2521 2522 /* operands have integer types (checked in typeok) */ 2523 if (pflag && !is_uinteger(olt)) { 2524 integer_constraints lc = ic_expr(ln); 2525 if (lc.bclr >> 63 != 0) 2526 return; 2527 2528 if (ln->tn_op != CON) 2529 /* bitwise '%s' on signed value possibly nonportable */ 2530 warning(117, op_name(op)); 2531 else if (ln->u.value.u.integer < 0) 2532 /* bitwise '%s' on signed value nonportable */ 2533 warning(120, op_name(op)); 2534 } else if (allow_trad && allow_c90 && 2535 !is_uinteger(olt) && is_uinteger(ort)) { 2536 /* The left operand would become unsigned in traditional C. */ 2537 if (hflag && (ln->tn_op != CON || ln->u.value.u.integer < 0)) { 2538 /* semantics of '%s' change in C90; use ... */ 2539 warning(118, op_name(op)); 2540 } 2541 } else if (allow_trad && allow_c90 && 2542 !is_uinteger(olt) && !is_uinteger(ort) && 2543 portable_rank_cmp(lt, rt) < 0) { 2544 /* 2545 * In traditional C, the left operand would be extended 2546 * (possibly sign-extended) and then shifted. 2547 */ 2548 if (hflag && (ln->tn_op != CON || ln->u.value.u.integer < 0)) { 2549 /* semantics of '%s' change in C90; use ... */ 2550 warning(118, op_name(op)); 2551 } 2552 } 2553 } 2554 2555 static void 2556 typeok_shl(op_t op, tspec_t lt, tspec_t rt) 2557 { 2558 /* 2559 * C90 does not perform balancing for shift operations, but traditional 2560 * C does. If the width of the right operand is greater than the width 2561 * of the left operand, then in traditional C the left operand would be 2562 * extended to the width of the right operand. For SHL this may result 2563 * in different results. 2564 */ 2565 if (portable_rank_cmp(lt, rt) < 0) { 2566 /* 2567 * XXX If both operands are constant, make sure that there is 2568 * really a difference between C90 and traditional C. 2569 */ 2570 if (hflag && allow_trad && allow_c90) 2571 /* semantics of '%s' change in C90; use ... */ 2572 warning(118, op_name(op)); 2573 } 2574 } 2575 2576 static void 2577 typeok_shift(const type_t *ltp, tspec_t lt, const tnode_t *rn, tspec_t rt) 2578 { 2579 if (rn->tn_op != CON) 2580 return; 2581 2582 if (!is_uinteger(rt) && rn->u.value.u.integer < 0) 2583 /* negative shift */ 2584 warning(121); 2585 else if ((uint64_t)rn->u.value.u.integer == size_in_bits(lt)) 2586 /* shift amount %u equals bit-size of '%s' */ 2587 warning(267, (unsigned)rn->u.value.u.integer, type_name(ltp)); 2588 else if ((uint64_t)rn->u.value.u.integer > size_in_bits(lt)) { 2589 /* shift amount %llu is greater than bit-size %llu of '%s' */ 2590 warning(122, (unsigned long long)rn->u.value.u.integer, 2591 (unsigned long long)size_in_bits(lt), 2592 tspec_name(lt)); 2593 } 2594 } 2595 2596 static bool 2597 is_typeok_eq(const tnode_t *ln, tspec_t lt, const tnode_t *rn, tspec_t rt) 2598 { 2599 if (lt == PTR && is_null_pointer(rn)) 2600 return true; 2601 if (rt == PTR && is_null_pointer(ln)) 2602 return true; 2603 return false; 2604 } 2605 2606 static void 2607 warn_incompatible_pointers(op_t op, const type_t *ltp, const type_t *rtp) 2608 { 2609 lint_assert(ltp->t_tspec == PTR); 2610 lint_assert(rtp->t_tspec == PTR); 2611 2612 tspec_t lt = ltp->t_subt->t_tspec; 2613 tspec_t rt = rtp->t_subt->t_tspec; 2614 2615 if (is_struct_or_union(lt) && is_struct_or_union(rt)) { 2616 if (op == RETURN) 2617 /* illegal structure pointer combination */ 2618 warning(244); 2619 else { 2620 /* incompatible structure pointers: '%s' '%s' '%s' */ 2621 warning(245, type_name(ltp), 2622 op_name(op), type_name(rtp)); 2623 } 2624 } else { 2625 if (op == RETURN) 2626 /* illegal combination of '%s' and '%s' */ 2627 warning(184, type_name(ltp), type_name(rtp)); 2628 else { 2629 /* illegal combination of '%s' and '%s', op '%s' */ 2630 warning(124, 2631 type_name(ltp), type_name(rtp), op_name(op)); 2632 } 2633 } 2634 } 2635 2636 static void 2637 check_pointer_comparison(op_t op, const tnode_t *ln, const tnode_t *rn) 2638 { 2639 type_t *ltp = ln->tn_type, *rtp = rn->tn_type; 2640 tspec_t lst = ltp->t_subt->t_tspec, rst = rtp->t_subt->t_tspec; 2641 2642 if (lst == VOID || rst == VOID) { 2643 /* TODO: C99 behaves like C90 here. */ 2644 if (!allow_trad && !allow_c99 && 2645 (lst == FUNC || rst == FUNC)) { 2646 /* (void *)0 is already handled in typeok() */ 2647 const char *lsts, *rsts; 2648 *(lst == FUNC ? &lsts : &rsts) = "function pointer"; 2649 *(lst == VOID ? &lsts : &rsts) = "'void *'"; 2650 /* C90 or later forbid comparison of %s with %s */ 2651 warning(274, lsts, rsts); 2652 } 2653 return; 2654 } 2655 2656 if (!types_compatible(ltp->t_subt, rtp->t_subt, true, false, NULL)) { 2657 warn_incompatible_pointers(op, ltp, rtp); 2658 return; 2659 } 2660 2661 if (lst == FUNC && rst == FUNC) { 2662 /* TODO: C99 behaves like C90 here, see C99 6.5.8p2. */ 2663 if (!allow_trad && !allow_c99 && op != EQ && op != NE) 2664 /* pointers to functions can only be compared ... */ 2665 warning(125); 2666 } 2667 } 2668 2669 static bool 2670 typeok_compare(op_t op, 2671 const tnode_t *ln, const type_t *ltp, tspec_t lt, 2672 const tnode_t *rn, const type_t *rtp, tspec_t rt) 2673 { 2674 if (lt == PTR && rt == PTR) { 2675 check_pointer_comparison(op, ln, rn); 2676 return true; 2677 } 2678 2679 if (lt != PTR && rt != PTR) 2680 return true; 2681 2682 if (!is_integer(lt) && !is_integer(rt)) { 2683 warn_incompatible_types(op, ltp, lt, rtp, rt); 2684 return false; 2685 } 2686 2687 const char *lx = lt == PTR ? "pointer" : "integer"; 2688 const char *rx = rt == PTR ? "pointer" : "integer"; 2689 /* illegal combination of %s '%s' and %s '%s', op '%s' */ 2690 warning(123, lx, type_name(ltp), rx, type_name(rtp), op_name(op)); 2691 return true; 2692 } 2693 2694 static bool 2695 typeok_quest(tspec_t lt, const tnode_t *rn) 2696 { 2697 if (!is_scalar(lt)) { 2698 /* first operand of '?' must have scalar type */ 2699 error(170); 2700 return false; 2701 } 2702 lint_assert(before_conversion(rn)->tn_op == COLON); 2703 return true; 2704 } 2705 2706 static void 2707 typeok_colon_pointer(const type_t *ltp, const type_t *rtp) 2708 { 2709 type_t *lstp = ltp->t_subt; 2710 type_t *rstp = rtp->t_subt; 2711 tspec_t lst = lstp->t_tspec; 2712 tspec_t rst = rstp->t_tspec; 2713 2714 if ((lst == VOID && rst == FUNC) || (lst == FUNC && rst == VOID)) { 2715 /* (void *)0 is handled in typeok_colon */ 2716 /* TODO: C99 behaves like C90 here. */ 2717 if (!allow_trad && !allow_c99) 2718 /* conversion of %s to %s requires a cast, op %s */ 2719 warning(305, "function pointer", "'void *'", 2720 op_name(COLON)); 2721 return; 2722 } 2723 2724 if (pointer_types_are_compatible(lstp, rstp, true)) 2725 return; 2726 if (!types_compatible(lstp, rstp, true, false, NULL)) 2727 warn_incompatible_pointers(COLON, ltp, rtp); 2728 } 2729 2730 static bool 2731 typeok_colon(const tnode_t *ln, const type_t *ltp, tspec_t lt, 2732 const tnode_t *rn, const type_t *rtp, tspec_t rt) 2733 { 2734 2735 if (is_arithmetic(lt) && is_arithmetic(rt)) 2736 return true; 2737 if (lt == BOOL && rt == BOOL) 2738 return true; 2739 2740 if (lt == STRUCT && rt == STRUCT && ltp->u.sou == rtp->u.sou) 2741 return true; 2742 if (lt == UNION && rt == UNION && ltp->u.sou == rtp->u.sou) 2743 return true; 2744 2745 if (lt == PTR && is_null_pointer(rn)) 2746 return true; 2747 if (rt == PTR && is_null_pointer(ln)) 2748 return true; 2749 2750 if ((lt == PTR && is_integer(rt)) || (is_integer(lt) && rt == PTR)) { 2751 const char *lx = lt == PTR ? "pointer" : "integer"; 2752 const char *rx = rt == PTR ? "pointer" : "integer"; 2753 /* illegal combination of %s '%s' and %s '%s', op '%s' */ 2754 warning(123, lx, type_name(ltp), 2755 rx, type_name(rtp), op_name(COLON)); 2756 return true; 2757 } 2758 2759 if (lt == VOID || rt == VOID) { 2760 if (lt != VOID || rt != VOID) 2761 /* incompatible types '%s' and '%s' in conditional */ 2762 warning(126, type_name(ltp), type_name(rtp)); 2763 return true; 2764 } 2765 2766 if (lt == PTR && rt == PTR) { 2767 typeok_colon_pointer(ltp, rtp); 2768 return true; 2769 } 2770 2771 /* incompatible types '%s' and '%s' in conditional */ 2772 error(126, type_name(ltp), type_name(rtp)); 2773 return false; 2774 } 2775 2776 static bool 2777 has_constant_member(const type_t *tp) 2778 { 2779 lint_assert(is_struct_or_union(tp->t_tspec)); 2780 2781 for (sym_t *m = tp->u.sou->sou_first_member; 2782 m != NULL; m = m->s_next) { 2783 const type_t *mtp = m->s_type; 2784 if (mtp->t_const) 2785 return true; 2786 if (is_struct_or_union(mtp->t_tspec) && 2787 has_constant_member(mtp)) 2788 return true; 2789 } 2790 return false; 2791 } 2792 2793 static bool 2794 typeok_assign(op_t op, const tnode_t *ln, const type_t *ltp, tspec_t lt) 2795 { 2796 if (op == RETURN || op == INIT || op == FARG) 2797 return true; 2798 2799 if (!ln->tn_lvalue) { 2800 if (ln->tn_op == CVT && ln->tn_cast && 2801 ln->u.ops.left->tn_op == LOAD) 2802 /* a cast does not yield an lvalue */ 2803 error(163); 2804 /* %soperand of '%s' must be lvalue */ 2805 error(114, "left ", op_name(op)); 2806 return false; 2807 } else if (ltp->t_const 2808 || (is_struct_or_union(lt) && has_constant_member(ltp))) { 2809 if (allow_c90) 2810 /* %soperand of '%s' must be modifiable lvalue */ 2811 warning(115, "left ", op_name(op)); 2812 } 2813 return true; 2814 } 2815 2816 static bool 2817 typeok_scalar(op_t op, const mod_t *mp, 2818 const type_t *ltp, tspec_t lt, 2819 const type_t *rtp, tspec_t rt) 2820 { 2821 if (mp->m_takes_bool && lt == BOOL && rt == BOOL) 2822 return true; 2823 if (mp->m_requires_integer) { 2824 if (!is_integer(lt) || (mp->m_binary && !is_integer(rt))) { 2825 warn_incompatible_types(op, ltp, lt, rtp, rt); 2826 return false; 2827 } 2828 } else if (mp->m_requires_integer_or_complex) { 2829 if ((!is_integer(lt) && !is_complex(lt)) || 2830 (mp->m_binary && (!is_integer(rt) && !is_complex(rt)))) { 2831 warn_incompatible_types(op, ltp, lt, rtp, rt); 2832 return false; 2833 } 2834 } else if (mp->m_requires_scalar) { 2835 if (!is_scalar(lt) || (mp->m_binary && !is_scalar(rt))) { 2836 warn_incompatible_types(op, ltp, lt, rtp, rt); 2837 return false; 2838 } 2839 } else if (mp->m_requires_arith) { 2840 if (!is_arithmetic(lt) || 2841 (mp->m_binary && !is_arithmetic(rt))) { 2842 warn_incompatible_types(op, ltp, lt, rtp, rt); 2843 return false; 2844 } 2845 } 2846 return true; 2847 } 2848 2849 static void 2850 check_assign_void_pointer(op_t op, int arg, 2851 tspec_t lt, tspec_t lst, 2852 tspec_t rt, tspec_t rst) 2853 { 2854 2855 if (!(lt == PTR && rt == PTR && (lst == VOID || rst == VOID))) 2856 return; 2857 /* two pointers, at least one pointer to void */ 2858 2859 /* TODO: C99 behaves like C90 here. */ 2860 if (!(!allow_trad && !allow_c99 && (lst == FUNC || rst == FUNC))) 2861 return; 2862 /* comb. of ptr to func and ptr to void */ 2863 2864 const char *lts, *rts; 2865 *(lst == FUNC ? <s : &rts) = "function pointer"; 2866 *(lst == VOID ? <s : &rts) = "'void *'"; 2867 2868 switch (op) { 2869 case INIT: 2870 case RETURN: 2871 /* conversion of %s to %s requires a cast */ 2872 warning(303, rts, lts); 2873 break; 2874 case FARG: 2875 /* conversion of %s to %s requires a cast, arg #%d */ 2876 warning(304, rts, lts, arg); 2877 break; 2878 default: 2879 /* conversion of %s to %s requires a cast, op %s */ 2880 warning(305, rts, lts, op_name(op)); 2881 break; 2882 } 2883 } 2884 2885 static bool 2886 is_direct_function_call(const tnode_t *tn, const char **out_name) 2887 { 2888 2889 if (tn->tn_op == CALL 2890 && tn->u.call->func->tn_op == ADDR 2891 && tn->u.call->func->u.ops.left->tn_op == NAME) { 2892 *out_name = tn->u.call->func->u.ops.left->u.sym->s_name; 2893 return true; 2894 } 2895 return false; 2896 } 2897 2898 static bool 2899 is_unconst_function(const char *name) 2900 { 2901 2902 return strcmp(name, "memchr") == 0 || 2903 strcmp(name, "strchr") == 0 || 2904 strcmp(name, "strpbrk") == 0 || 2905 strcmp(name, "strrchr") == 0 || 2906 strcmp(name, "strstr") == 0; 2907 } 2908 2909 static bool 2910 is_const_char_pointer(const tnode_t *tn) 2911 { 2912 /* 2913 * For traditional reasons, C99 6.4.5p5 defines that string literals 2914 * have type 'char[]'. They are often implicitly converted to 'char 2915 * *', for example when they are passed as function arguments. 2916 * 2917 * C99 6.4.5p6 further defines that modifying a string that is 2918 * constructed from a string literal invokes undefined behavior. 2919 * 2920 * Out of these reasons, string literals are treated as 'effectively 2921 * const' here. 2922 */ 2923 if (tn->tn_op == CVT && 2924 tn->u.ops.left->tn_op == ADDR && 2925 tn->u.ops.left->u.ops.left->tn_op == STRING) 2926 return true; 2927 2928 const type_t *tp = before_conversion(tn)->tn_type; 2929 return tp->t_tspec == PTR && 2930 tp->t_subt->t_tspec == CHAR && 2931 tp->t_subt->t_const; 2932 } 2933 2934 static bool 2935 is_const_pointer(const tnode_t *tn) 2936 { 2937 const type_t *tp = before_conversion(tn)->tn_type; 2938 return tp->t_tspec == PTR && tp->t_subt->t_const; 2939 } 2940 2941 static void 2942 check_unconst_function(const type_t *lstp, const tnode_t *rn) 2943 { 2944 const char *function_name; 2945 2946 if (lstp->t_tspec == CHAR && !lstp->t_const && 2947 is_direct_function_call(rn, &function_name) && 2948 is_unconst_function(function_name) && 2949 rn->u.call->args_len >= 1 && 2950 is_const_char_pointer(rn->u.call->args[0])) { 2951 /* call to '%s' effectively discards 'const' from argument */ 2952 warning(346, function_name); 2953 } 2954 2955 if (!lstp->t_const && 2956 is_direct_function_call(rn, &function_name) && 2957 strcmp(function_name, "bsearch") == 0 && 2958 rn->u.call->args_len >= 2 && 2959 is_const_pointer(rn->u.call->args[1])) { 2960 /* call to '%s' effectively discards 'const' from argument */ 2961 warning(346, function_name); 2962 } 2963 } 2964 2965 static bool 2966 check_assign_void_pointer_compat(op_t op, int arg, 2967 tspec_t lt, 2968 const type_t *lstp, tspec_t lst, 2969 const tnode_t *rn, 2970 const type_t *rtp, tspec_t rt, 2971 const type_t *rstp, tspec_t rst) 2972 { 2973 if (!(lt == PTR && rt == PTR && (lst == VOID || rst == VOID || 2974 types_compatible(lstp, rstp, 2975 true, false, NULL)))) 2976 return false; 2977 2978 /* compatible pointer types (qualifiers ignored) */ 2979 char qualifiers[32]; 2980 snprintf(qualifiers, sizeof(qualifiers), "%s%s", 2981 !lstp->t_const && rstp->t_const ? " const" : "", 2982 !lstp->t_volatile && rstp->t_volatile ? " volatile" : ""); 2983 if (allow_c90 && qualifiers[0] != '\0') { 2984 switch (op) { 2985 case INIT: 2986 case RETURN: 2987 /* '%s' discards '%s' from '%s' */ 2988 warning(182, op_name(op), 2989 qualifiers + 1, type_name(rtp)); 2990 break; 2991 case FARG: 2992 /* passing '%s' to argument %d discards '%s' */ 2993 warning(383, type_name(rtp), arg, qualifiers + 1); 2994 break; 2995 default: 2996 /* operator '%s' discards '%s' from '%s' */ 2997 warning(128, op_name(op), 2998 qualifiers + 1, type_name(rtp)); 2999 break; 3000 } 3001 } 3002 3003 if (allow_c90) 3004 check_unconst_function(lstp, rn); 3005 3006 return true; 3007 } 3008 3009 static bool 3010 check_assign_pointer_integer(op_t op, int arg, 3011 const type_t *ltp, tspec_t lt, 3012 const type_t *rtp, tspec_t rt) 3013 { 3014 3015 if (!((lt == PTR && is_integer(rt)) || (is_integer(lt) && rt == PTR))) 3016 return false; 3017 3018 const char *lx = lt == PTR ? "pointer" : "integer"; 3019 const char *rx = rt == PTR ? "pointer" : "integer"; 3020 3021 switch (op) { 3022 case INIT: 3023 case RETURN: 3024 /* illegal combination of %s '%s' and %s '%s' */ 3025 warning(183, lx, type_name(ltp), rx, type_name(rtp)); 3026 break; 3027 case FARG: 3028 /* illegal combination of %s '%s' and %s '%s', arg #%d */ 3029 warning(154, 3030 lx, type_name(ltp), rx, type_name(rtp), arg); 3031 break; 3032 default: 3033 /* illegal combination of %s '%s' and %s '%s', op '%s' */ 3034 warning(123, 3035 lx, type_name(ltp), rx, type_name(rtp), op_name(op)); 3036 break; 3037 } 3038 return true; 3039 } 3040 3041 static bool 3042 check_assign_pointer(op_t op, int arg, 3043 const type_t *ltp, tspec_t lt, 3044 const type_t *rtp, tspec_t rt) 3045 { 3046 if (!(lt == PTR && rt == PTR)) 3047 return false; 3048 3049 if (op == FARG) 3050 /* converting '%s' to incompatible '%s' for ... */ 3051 warning(153, type_name(rtp), type_name(ltp), arg); 3052 else 3053 warn_incompatible_pointers(op, ltp, rtp); 3054 return true; 3055 } 3056 3057 static void 3058 warn_assign(op_t op, int arg, 3059 const type_t *ltp, tspec_t lt, 3060 const type_t *rtp, tspec_t rt) 3061 { 3062 switch (op) { 3063 case INIT: 3064 /* cannot initialize '%s' from '%s' */ 3065 error(185, type_name(ltp), type_name(rtp)); 3066 break; 3067 case RETURN: 3068 /* function has return type '%s' but returns '%s' */ 3069 error(211, type_name(ltp), type_name(rtp)); 3070 break; 3071 case FARG: 3072 /* passing '%s' to incompatible '%s', arg #%d */ 3073 warning(155, type_name(rtp), type_name(ltp), arg); 3074 break; 3075 default: 3076 warn_incompatible_types(op, ltp, lt, rtp, rt); 3077 break; 3078 } 3079 } 3080 3081 /* 3082 * Checks type compatibility for ASSIGN, INIT, FARG and RETURN 3083 * and prints warnings/errors if necessary. 3084 * Returns whether the types are (almost) compatible. 3085 */ 3086 static bool 3087 check_assign_types_compatible(op_t op, int arg, 3088 const tnode_t *ln, const tnode_t *rn) 3089 { 3090 tspec_t lt, rt, lst = NO_TSPEC, rst = NO_TSPEC; 3091 type_t *ltp, *rtp, *lstp = NULL, *rstp = NULL; 3092 3093 if ((lt = (ltp = ln->tn_type)->t_tspec) == PTR) 3094 lst = (lstp = ltp->t_subt)->t_tspec; 3095 if ((rt = (rtp = rn->tn_type)->t_tspec) == PTR) 3096 rst = (rstp = rtp->t_subt)->t_tspec; 3097 3098 if (lt == BOOL && is_scalar(rt)) /* C99 6.3.1.2 */ 3099 return true; 3100 3101 if (is_arithmetic(lt) && (is_arithmetic(rt) || rt == BOOL)) 3102 return true; 3103 3104 if (is_struct_or_union(lt) && is_struct_or_union(rt)) 3105 return ltp->u.sou == rtp->u.sou; 3106 3107 if (lt == PTR && is_null_pointer(rn)) { 3108 if (is_integer(rn->tn_type->t_tspec)) 3109 /* implicit conversion from integer 0 to pointer ... */ 3110 query_message(15, type_name(ltp)); 3111 return true; 3112 } 3113 3114 check_assign_void_pointer(op, arg, lt, lst, rt, rst); 3115 3116 if (check_assign_void_pointer_compat(op, arg, 3117 lt, lstp, lst, rn, rtp, rt, rstp, rst)) 3118 return true; 3119 3120 if (check_assign_pointer_integer(op, arg, ltp, lt, rtp, rt)) 3121 return true; 3122 3123 if (check_assign_pointer(op, arg, ltp, lt, rtp, rt)) 3124 return true; 3125 3126 warn_assign(op, arg, ltp, lt, rtp, rt); 3127 return false; 3128 } 3129 3130 static bool 3131 has_side_effect(const tnode_t *tn) /* NOLINT(misc-no-recursion) */ 3132 { 3133 op_t op = tn->tn_op; 3134 3135 if (modtab[op].m_has_side_effect) 3136 return true; 3137 3138 if (op == CVT && tn->tn_type->t_tspec == VOID) 3139 return has_side_effect(tn->u.ops.left); 3140 3141 /* XXX: Why not has_side_effect(tn->u.ops.left) as well? */ 3142 if (op == LOGAND || op == LOGOR) 3143 return has_side_effect(tn->u.ops.right); 3144 3145 /* XXX: Why not has_side_effect(tn->u.ops.left) as well? */ 3146 if (op == QUEST) 3147 return has_side_effect(tn->u.ops.right); 3148 3149 if (op == COLON || op == COMMA) { 3150 return has_side_effect(tn->u.ops.left) || 3151 has_side_effect(tn->u.ops.right); 3152 } 3153 3154 return false; 3155 } 3156 3157 static bool 3158 is_void_cast(const tnode_t *tn) 3159 { 3160 3161 return tn->tn_op == CVT && tn->tn_cast && 3162 tn->tn_type->t_tspec == VOID; 3163 } 3164 3165 static bool 3166 is_local_symbol(const tnode_t *tn) 3167 { 3168 3169 return tn->tn_op == LOAD && 3170 tn->u.ops.left->tn_op == NAME && 3171 tn->u.ops.left->u.sym->s_scl == AUTO; 3172 } 3173 3174 static bool 3175 is_int_constant_zero(const tnode_t *tn) 3176 { 3177 3178 return tn->tn_op == CON && 3179 tn->tn_type->t_tspec == INT && 3180 tn->u.value.u.integer == 0; 3181 } 3182 3183 static void 3184 check_null_effect(const tnode_t *tn) 3185 { 3186 3187 if (hflag && 3188 !has_side_effect(tn) && 3189 !(is_void_cast(tn) && is_local_symbol(tn->u.ops.left)) && 3190 !(is_void_cast(tn) && is_int_constant_zero(tn->u.ops.left))) { 3191 /* expression has null effect */ 3192 warning(129); 3193 } 3194 } 3195 3196 /* 3197 * Check the types for specific operators and type combinations. 3198 * 3199 * At this point, the operands already conform to the type requirements of 3200 * the operator, such as being integer, floating or scalar. 3201 */ 3202 static bool 3203 typeok_op(op_t op, int arg, 3204 const tnode_t *ln, const type_t *ltp, tspec_t lt, 3205 const tnode_t *rn, const type_t *rtp, tspec_t rt) 3206 { 3207 switch (op) { 3208 case ARROW: 3209 return typeok_arrow(lt); 3210 case POINT: 3211 return typeok_point(ln, ltp, lt); 3212 case INCBEF: 3213 case DECBEF: 3214 case INCAFT: 3215 case DECAFT: 3216 return typeok_incdec(op, ln, ltp); 3217 case INDIR: 3218 return typeok_indir(ltp, lt); 3219 case ADDR: 3220 return typeok_address(op, ln, ltp, lt); 3221 case PLUS: 3222 return typeok_plus(op, ltp, lt, rtp, rt); 3223 case MINUS: 3224 return typeok_minus(op, ltp, lt, rtp, rt); 3225 case SHL: 3226 typeok_shl(op, lt, rt); 3227 goto shift; 3228 case SHR: 3229 typeok_shr(op, ln, lt, rn, rt); 3230 shift: 3231 typeok_shift(ltp, lt, rn, rt); 3232 break; 3233 case LT: 3234 case LE: 3235 case GT: 3236 case GE: 3237 compare: 3238 return typeok_compare(op, ln, ltp, lt, rn, rtp, rt); 3239 case EQ: 3240 case NE: 3241 if (is_typeok_eq(ln, lt, rn, rt)) 3242 break; 3243 goto compare; 3244 case QUEST: 3245 return typeok_quest(lt, rn); 3246 case COLON: 3247 return typeok_colon(ln, ltp, lt, rn, rtp, rt); 3248 case ASSIGN: 3249 case INIT: 3250 case FARG: 3251 case RETURN: 3252 if (!check_assign_types_compatible(op, arg, ln, rn)) 3253 return false; 3254 goto assign; 3255 case MULASS: 3256 case DIVASS: 3257 case MODASS: 3258 goto assign; 3259 case ADDASS: 3260 case SUBASS: 3261 if ((lt == PTR && !is_integer(rt)) || rt == PTR) { 3262 warn_incompatible_types(op, ltp, lt, rtp, rt); 3263 return false; 3264 } 3265 goto assign; 3266 case SHLASS: 3267 goto assign; 3268 case SHRASS: 3269 if (pflag && !is_uinteger(lt) && 3270 !(!allow_c90 && is_uinteger(rt))) { 3271 /* bitwise '%s' on signed value possibly nonportable */ 3272 warning(117, op_name(op)); 3273 } 3274 goto assign; 3275 case ANDASS: 3276 case XORASS: 3277 case ORASS: 3278 assign: 3279 return typeok_assign(op, ln, ltp, lt); 3280 case COMMA: 3281 if (!modtab[ln->tn_op].m_has_side_effect) 3282 check_null_effect(ln); 3283 break; 3284 default: 3285 break; 3286 } 3287 return true; 3288 } 3289 3290 static void 3291 check_bad_enum_operation(op_t op, const tnode_t *ln, const tnode_t *rn) 3292 { 3293 3294 if (!eflag) 3295 return; 3296 3297 /* Allow enum in array indices. */ 3298 if (op == PLUS && 3299 ((ln->tn_type->t_is_enum && rn->tn_type->t_tspec == PTR) || 3300 (rn->tn_type->t_is_enum && ln->tn_type->t_tspec == PTR))) { 3301 return; 3302 } 3303 3304 /* dubious operation '%s' on enum */ 3305 warning(241, op_name(op)); 3306 } 3307 3308 static void 3309 check_enum_type_mismatch(op_t op, int arg, const tnode_t *ln, const tnode_t *rn) 3310 { 3311 const mod_t *mp = &modtab[op]; 3312 3313 if (ln->tn_type->u.enumer != rn->tn_type->u.enumer) { 3314 switch (op) { 3315 case INIT: 3316 /* enum type mismatch between '%s' and '%s' in ... */ 3317 warning(210, 3318 type_name(ln->tn_type), type_name(rn->tn_type)); 3319 break; 3320 case FARG: 3321 /* function expects '%s', passing '%s' for arg #%d */ 3322 warning(156, 3323 type_name(ln->tn_type), type_name(rn->tn_type), 3324 arg); 3325 break; 3326 case RETURN: 3327 /* function has return type '%s' but returns '%s' */ 3328 warning(211, 3329 type_name(ln->tn_type), type_name(rn->tn_type)); 3330 break; 3331 default: 3332 /* enum type mismatch: '%s' '%s' '%s' */ 3333 warning(130, type_name(ln->tn_type), op_name(op), 3334 type_name(rn->tn_type)); 3335 break; 3336 } 3337 } else if (Pflag && eflag && mp->m_comparison && op != EQ && op != NE) 3338 /* operator '%s' assumes that '%s' is ordered */ 3339 warning(243, op_name(op), type_name(ln->tn_type)); 3340 } 3341 3342 static void 3343 check_enum_int_mismatch(op_t op, int arg, const tnode_t *ln, const tnode_t *rn) 3344 { 3345 3346 if (!eflag) 3347 return; 3348 3349 switch (op) { 3350 case INIT: 3351 /* 3352 * Initialization with 0 is allowed. Otherwise, all implicit 3353 * initializations would need to be warned upon as well. 3354 */ 3355 if (!rn->tn_type->t_is_enum && rn->tn_op == CON && 3356 is_integer(rn->tn_type->t_tspec) && 3357 rn->u.value.u.integer == 0) { 3358 return; 3359 } 3360 /* initialization of '%s' with '%s' */ 3361 warning(277, type_name(ln->tn_type), type_name(rn->tn_type)); 3362 break; 3363 case FARG: 3364 /* combination of '%s' and '%s', arg #%d */ 3365 warning(278, 3366 type_name(ln->tn_type), type_name(rn->tn_type), arg); 3367 break; 3368 case RETURN: 3369 /* combination of '%s' and '%s' in return */ 3370 warning(279, type_name(ln->tn_type), type_name(rn->tn_type)); 3371 break; 3372 default: 3373 /* combination of '%s' and '%s', op '%s' */ 3374 warning(242, type_name(ln->tn_type), type_name(rn->tn_type), 3375 op_name(op)); 3376 break; 3377 } 3378 } 3379 3380 static void 3381 typeok_enum(op_t op, const mod_t *mp, int arg, 3382 const tnode_t *ln, const type_t *ltp, 3383 const tnode_t *rn, const type_t *rtp) 3384 { 3385 if (mp->m_bad_on_enum && 3386 (ltp->t_is_enum || (mp->m_binary && rtp->t_is_enum))) { 3387 check_bad_enum_operation(op, ln, rn); 3388 } else if (mp->m_valid_on_enum && 3389 (ltp->t_is_enum && rtp != NULL && rtp->t_is_enum)) { 3390 check_enum_type_mismatch(op, arg, ln, rn); 3391 } else if (mp->m_valid_on_enum && 3392 (ltp->t_is_enum || (rtp != NULL && rtp->t_is_enum))) { 3393 check_enum_int_mismatch(op, arg, ln, rn); 3394 } 3395 } 3396 3397 /* Perform most type checks. Return whether the types are ok. */ 3398 bool 3399 typeok(op_t op, int arg, const tnode_t *ln, const tnode_t *rn) 3400 { 3401 3402 const mod_t *mp = &modtab[op]; 3403 3404 type_t *ltp = ln->tn_type; 3405 tspec_t lt = ltp->t_tspec; 3406 3407 type_t *rtp = mp->m_binary ? rn->tn_type : NULL; 3408 tspec_t rt = mp->m_binary ? rtp->t_tspec : NO_TSPEC; 3409 3410 if (Tflag && !typeok_scalar_strict_bool(op, mp, arg, ln, rn)) 3411 return false; 3412 if (!typeok_scalar(op, mp, ltp, lt, rtp, rt)) 3413 return false; 3414 3415 if (!typeok_op(op, arg, ln, ltp, lt, rn, rtp, rt)) 3416 return false; 3417 3418 typeok_enum(op, mp, arg, ln, ltp, rn, rtp); 3419 return true; 3420 } 3421 3422 /* In traditional C, keep unsigned and promote FLOAT to DOUBLE. */ 3423 static tspec_t 3424 promote_trad(tspec_t t) 3425 { 3426 3427 if (t == UCHAR || t == USHORT) 3428 return UINT; 3429 if (t == CHAR || t == SCHAR || t == SHORT) 3430 return INT; 3431 if (t == FLOAT) 3432 return DOUBLE; 3433 if (t == ENUM) 3434 return INT; 3435 return t; 3436 } 3437 3438 /* 3439 * C99 6.3.1.1p2 requires for types with lower rank than int that "If an int 3440 * can represent all the values of the original type, the value is converted 3441 * to an int; otherwise it is converted to an unsigned int", and that "All 3442 * other types are unchanged by the integer promotions". 3443 */ 3444 static tspec_t 3445 promote_c90(const tnode_t *tn, tspec_t t, bool farg) 3446 { 3447 if (tn->tn_type->t_bitfield) { 3448 unsigned int width = tn->tn_type->t_bit_field_width; 3449 unsigned int int_width = size_in_bits(INT); 3450 // XXX: What about _Bool bit-fields, since C99? 3451 if (width < int_width) 3452 return INT; 3453 if (width == int_width) 3454 return is_uinteger(t) ? UINT : INT; 3455 return t; 3456 } 3457 3458 if (t == CHAR || t == SCHAR) 3459 return INT; 3460 if (t == UCHAR) 3461 return size_in_bits(CHAR) < size_in_bits(INT) ? INT : UINT; 3462 if (t == SHORT) 3463 return INT; 3464 if (t == USHORT) 3465 return size_in_bits(SHORT) < size_in_bits(INT) ? INT : UINT; 3466 if (t == ENUM) 3467 return INT; 3468 if (farg && t == FLOAT) 3469 return DOUBLE; 3470 return t; 3471 } 3472 3473 /* 3474 * Performs the "integer promotions" (C99 6.3.1.1p2), which convert small 3475 * integer types to either int or unsigned int. 3476 * 3477 * If allow_c90 is unset or the operand is a function argument with no type 3478 * information (no prototype or variable # of args), converts float to double. 3479 */ 3480 tnode_t * 3481 promote(op_t op, bool farg, tnode_t *tn) 3482 { 3483 3484 const type_t *otp = tn->tn_type; 3485 tspec_t ot = otp->t_tspec; 3486 if (!is_arithmetic(ot)) 3487 return tn; 3488 3489 tspec_t nt = allow_c90 ? promote_c90(tn, ot, farg) : promote_trad(ot); 3490 if (nt == ot) 3491 return tn; 3492 3493 type_t *ntp = expr_dup_type(gettyp(nt)); 3494 ntp->t_tspec = nt; 3495 ntp->t_is_enum = otp->t_is_enum; 3496 if (ntp->t_is_enum) 3497 ntp->u.enumer = otp->u.enumer; 3498 ntp->t_bitfield = otp->t_bitfield; 3499 if (ntp->t_bitfield) { 3500 ntp->t_bit_field_width = otp->t_bit_field_width; 3501 ntp->t_bit_field_offset = otp->t_bit_field_offset; 3502 } 3503 if (ntp->t_bitfield && is_uinteger(ot) && !is_uinteger(nt)) 3504 ntp->t_bit_field_width++; 3505 return convert(op, 0, ntp, tn); 3506 } 3507 3508 static void 3509 check_lossy_floating_to_integer_conversion( 3510 op_t op, int arg, const type_t *tp, const tnode_t *tn) 3511 { 3512 long double x = tn->u.value.u.floating; 3513 integer_constraints ic = ic_any(tp); 3514 if (is_uinteger(tp->t_tspec) 3515 ? x >= ic.umin && x <= ic.umax && x == (uint64_t)x 3516 : x >= ic.smin && x <= ic.smax && x == (int64_t)x) 3517 return; 3518 if (op == FARG) 3519 /* lossy conversion of %Lg to '%s', arg #%d */ 3520 warning(380, x, type_name(tp), arg); 3521 else 3522 /* lossy conversion of %Lg to '%s' */ 3523 warning(381, x, type_name(tp)); 3524 } 3525 3526 static void 3527 convert_integer_from_floating( 3528 op_t op, int arg, const type_t *tp, const tnode_t *tn) 3529 { 3530 3531 if (op == CVT) 3532 /* cast from floating point '%s' to integer '%s' */ 3533 query_message(2, type_name(tn->tn_type), type_name(tp)); 3534 else 3535 /* implicit conversion from floating point '%s' to ... */ 3536 query_message(1, type_name(tn->tn_type), type_name(tp)); 3537 if (tn->tn_op == CON) 3538 check_lossy_floating_to_integer_conversion(op, arg, tp, tn); 3539 } 3540 3541 static bool 3542 should_warn_about_prototype_conversion(tspec_t nt, 3543 tspec_t ot, const tnode_t *ptn) 3544 { 3545 3546 if (nt == ot) 3547 return false; 3548 3549 if (nt == ENUM && ot == INT) 3550 return false; 3551 3552 if (is_floating(nt) != is_floating(ot) || 3553 portable_rank_cmp(nt, ot) != 0) { 3554 /* representation and/or width change */ 3555 if (!is_integer(ot)) 3556 return true; 3557 /* 3558 * XXX: Investigate whether this rule makes sense; see 3559 * tests/usr.bin/xlint/lint1/platform_long.c. 3560 */ 3561 return portable_rank_cmp(ot, INT) > 0; 3562 } 3563 3564 if (!hflag) 3565 return false; 3566 3567 /* 3568 * If the types differ only in sign and the argument has the same 3569 * representation in both types, print no warning. 3570 */ 3571 if (ptn->tn_op == CON && is_integer(nt) && 3572 signed_type(nt) == signed_type(ot) && 3573 !msb(ptn->u.value.u.integer, ot)) 3574 return false; 3575 3576 return true; 3577 } 3578 3579 /* 3580 * Warn if a prototype causes a type conversion that is different from what 3581 * would happen to the same argument in the absence of a prototype. This 3582 * check is intended for code that needs to stay compatible with pre-C90 C. 3583 * 3584 * Errors/warnings about illegal type combinations are already printed 3585 * in check_assign_types_compatible(). 3586 */ 3587 static void 3588 check_prototype_conversion(int arg, tspec_t nt, tspec_t ot, type_t *tp, 3589 tnode_t *tn) 3590 { 3591 3592 if (!is_arithmetic(nt) || !is_arithmetic(ot)) 3593 return; 3594 3595 /* 3596 * If the type of the formal parameter is char/short, a warning would 3597 * be useless, because functions declared the old style can't expect 3598 * char/short arguments. 3599 */ 3600 if (nt == CHAR || nt == SCHAR || nt == UCHAR || 3601 nt == SHORT || nt == USHORT) 3602 return; 3603 3604 tnode_t *ptn = promote(NOOP, true, tn); 3605 ot = ptn->tn_type->t_tspec; 3606 3607 if (should_warn_about_prototype_conversion(nt, ot, ptn)) { 3608 /* argument %d is converted from '%s' to '%s' ... */ 3609 warning(259, arg, type_name(tn->tn_type), type_name(tp)); 3610 } 3611 } 3612 3613 /* 3614 * When converting a large integer type to a small integer type, in some 3615 * cases the value of the actual expression is further restricted than the 3616 * type bounds, such as in (expr & 0xFF) or (expr % 100) or (expr >> 24). 3617 */ 3618 static bool 3619 can_represent(const type_t *tp, const tnode_t *tn) 3620 { 3621 uint64_t nmask = value_bits(width_in_bits(tp)); 3622 if (!is_uinteger(tp->t_tspec)) 3623 nmask >>= 1; 3624 3625 integer_constraints c = ic_expr(tn); 3626 if ((~c.bclr & ~nmask) == 0) 3627 return true; 3628 3629 integer_constraints tpc = ic_any(tp); 3630 if (is_uinteger(tp->t_tspec) 3631 ? tpc.umin <= c.umin && tpc.umax >= c.umax 3632 : tpc.smin <= c.smin && tpc.smax >= c.smax) 3633 return true; 3634 3635 debug_enter(); 3636 debug_step("type '%s' cannot represent:", type_name(tp)); 3637 debug_node(tn); 3638 debug_leave(); 3639 return false; 3640 } 3641 3642 static bool 3643 should_warn_about_integer_conversion(const type_t *ntp, tspec_t nt, 3644 const tnode_t *otn, tspec_t ot) 3645 { 3646 3647 // XXX: The portable_rank_cmp aims at portable mode, independent of the 3648 // current platform, while can_represent acts on the actual type sizes 3649 // from the current platform. This mix is inconsistent, but anything 3650 // else would make the exact conditions too complicated to grasp. 3651 if (aflag > 0 && portable_rank_cmp(nt, ot) < 0) { 3652 if (ot == LONG || ot == ULONG 3653 || ot == LLONG || ot == ULLONG 3654 #ifdef INT128_SIZE 3655 || ot == INT128 || ot == UINT128 3656 #endif 3657 || aflag > 1) 3658 return !can_represent(ntp, otn); 3659 } 3660 return false; 3661 } 3662 3663 static void 3664 convert_integer_from_integer(op_t op, int arg, tspec_t nt, tspec_t ot, 3665 type_t *tp, tnode_t *tn) 3666 { 3667 3668 if (tn->tn_op == CON) 3669 return; 3670 3671 if (op == CVT) 3672 return; 3673 3674 if (Pflag && pflag && aflag > 0 && 3675 portable_rank_cmp(nt, ot) > 0 && 3676 is_uinteger(nt) != is_uinteger(ot)) { 3677 if (op == FARG) 3678 /* conversion to '%s' may sign-extend ... */ 3679 warning(297, type_name(tp), arg); 3680 else 3681 /* conversion to '%s' may sign-extend ... */ 3682 warning(131, type_name(tp)); 3683 } 3684 3685 if (Pflag && portable_rank_cmp(nt, ot) > 0 && 3686 (tn->tn_op == PLUS || tn->tn_op == MINUS || tn->tn_op == MULT || 3687 tn->tn_op == SHL)) { 3688 /* suggest cast from '%s' to '%s' on op '%s' to ... */ 3689 warning(324, type_name(gettyp(ot)), type_name(tp), 3690 op_name(tn->tn_op)); 3691 } 3692 3693 if (should_warn_about_integer_conversion(tp, nt, tn, ot)) { 3694 if (op == FARG) { 3695 /* conversion from '%s' to '%s' may lose ... */ 3696 warning(298, 3697 type_name(tn->tn_type), type_name(tp), arg); 3698 } else { 3699 /* conversion from '%s' to '%s' may lose accuracy */ 3700 warning(132, 3701 type_name(tn->tn_type), type_name(tp)); 3702 } 3703 } 3704 3705 if (is_uinteger(nt) != is_uinteger(ot)) 3706 /* implicit conversion changes sign from '%s' to '%s' */ 3707 query_message(3, type_name(tn->tn_type), type_name(tp)); 3708 } 3709 3710 static void 3711 convert_integer_from_pointer(op_t op, tspec_t nt, type_t *tp, tnode_t *tn) 3712 { 3713 3714 if (tn->tn_op == CON) 3715 return; 3716 if (op != CVT) 3717 return; /* We already got an error. */ 3718 if (portable_rank_cmp(nt, PTR) >= 0) 3719 return; 3720 3721 if (pflag && size_in_bits(nt) >= size_in_bits(PTR)) { 3722 /* conversion of pointer to '%s' may lose bits */ 3723 warning(134, type_name(tp)); 3724 } else { 3725 /* conversion of pointer to '%s' loses bits */ 3726 warning(133, type_name(tp)); 3727 } 3728 } 3729 3730 static bool 3731 struct_starts_with(const type_t *struct_tp, const type_t *member_tp) 3732 { 3733 3734 return struct_tp->u.sou->sou_first_member != NULL && 3735 types_compatible(struct_tp->u.sou->sou_first_member->s_type, 3736 member_tp, true, false, NULL); 3737 } 3738 3739 static bool 3740 is_byte_array(const type_t *tp) 3741 { 3742 3743 return tp->t_tspec == ARRAY && 3744 (tp->t_subt->t_tspec == CHAR || tp->t_subt->t_tspec == UCHAR); 3745 } 3746 3747 static bool 3748 union_contains(const type_t *utp, const type_t *mtp) 3749 { 3750 for (const sym_t *mem = utp->u.sou->sou_first_member; 3751 mem != NULL; mem = mem->s_next) { 3752 if (types_compatible(mem->s_type, mtp, true, false, NULL)) 3753 return true; 3754 } 3755 return false; 3756 } 3757 3758 static bool 3759 should_warn_about_pointer_cast(const type_t *nstp, tspec_t nst, 3760 const type_t *ostp, tspec_t ost) 3761 { 3762 3763 while (nst == ARRAY) 3764 nstp = nstp->t_subt, nst = nstp->t_tspec; 3765 while (ost == ARRAY) 3766 ostp = ostp->t_subt, ost = ostp->t_tspec; 3767 3768 if (nst == STRUCT && ost == STRUCT && 3769 (struct_starts_with(nstp, ostp) || 3770 struct_starts_with(ostp, nstp))) 3771 return false; 3772 3773 if (is_incomplete(nstp) || is_incomplete(ostp)) 3774 return false; 3775 3776 if (nst == CHAR || nst == UCHAR) 3777 return false; /* for the sake of traditional C code */ 3778 if (ost == CHAR || ost == UCHAR) 3779 return false; /* for the sake of traditional C code */ 3780 3781 /* Allow cast between pointers to sockaddr variants. */ 3782 if (nst == STRUCT && ost == STRUCT) { 3783 const sym_t *nmem = nstp->u.sou->sou_first_member; 3784 const sym_t *omem = ostp->u.sou->sou_first_member; 3785 while (nmem != NULL && omem != NULL && 3786 types_compatible(nmem->s_type, omem->s_type, 3787 true, false, NULL)) 3788 nmem = nmem->s_next, omem = omem->s_next; 3789 if (nmem != NULL && is_byte_array(nmem->s_type)) 3790 return false; 3791 if (omem != NULL && is_byte_array(omem->s_type)) 3792 return false; 3793 if (nmem == NULL && omem == NULL) 3794 return false; 3795 } 3796 3797 if (nst == UNION || ost == UNION) { 3798 const type_t *union_tp = nst == UNION ? nstp : ostp; 3799 const type_t *other_tp = nst == UNION ? ostp : nstp; 3800 if (union_contains(union_tp, other_tp)) 3801 return false; 3802 } 3803 3804 if (is_struct_or_union(nst) && is_struct_or_union(ost)) 3805 return nstp->u.sou != ostp->u.sou; 3806 3807 enum rank_kind rk1 = type_properties(nst)->tt_rank_kind; 3808 enum rank_kind rk2 = type_properties(ost)->tt_rank_kind; 3809 if (rk1 != rk2 || rk1 == RK_NONE) 3810 return true; 3811 3812 return portable_rank_cmp(nst, ost) != 0; 3813 } 3814 3815 static void 3816 convert_pointer_from_pointer(type_t *ntp, tnode_t *tn) 3817 { 3818 const type_t *nstp = ntp->t_subt; 3819 const type_t *otp = tn->tn_type; 3820 const type_t *ostp = otp->t_subt; 3821 tspec_t nst = nstp->t_tspec; 3822 tspec_t ost = ostp->t_tspec; 3823 3824 if (nst == VOID || ost == VOID) { 3825 /* TODO: C99 behaves like C90 here. */ 3826 if (!allow_trad && !allow_c99 && (nst == FUNC || ost == FUNC)) { 3827 const char *nts, *ots; 3828 /* null pointers are already handled in convert() */ 3829 *(nst == FUNC ? &nts : &ots) = "function pointer"; 3830 *(nst == VOID ? &nts : &ots) = "'void *'"; 3831 /* conversion of %s to %s requires a cast */ 3832 warning(303, ots, nts); 3833 } 3834 return; 3835 } 3836 if (nst == FUNC && ost == FUNC) 3837 return; 3838 if (nst == FUNC || ost == FUNC) { 3839 /* converting '%s' to '%s' is questionable */ 3840 warning(229, type_name(otp), type_name(ntp)); 3841 return; 3842 } 3843 3844 if (hflag && alignment(nstp) > alignment(ostp) && 3845 ost != CHAR && ost != UCHAR && 3846 !is_incomplete(ostp) && 3847 !(nst == UNION && union_contains(nstp, ostp))) { 3848 /* converting '%s' to '%s' increases alignment ... */ 3849 warning(135, type_name(otp), type_name(ntp), 3850 alignment(ostp), alignment(nstp)); 3851 } 3852 3853 if (cflag && should_warn_about_pointer_cast(nstp, nst, ostp, ost)) { 3854 /* pointer cast from '%s' to unrelated '%s' */ 3855 warning(247, type_name(ostp), type_name(nstp)); 3856 } 3857 } 3858 3859 /* 3860 * Insert a conversion operator, which converts the type of the node 3861 * to another given type. 3862 * 3863 * Possible values for 'op': 3864 * CVT a cast-expression 3865 * binary integer promotion for one of the operands, or a usual 3866 * arithmetic conversion 3867 * binary plain or compound assignments to bit-fields 3868 * FARG 'arg' is the number of the parameter (used for warnings) 3869 * NOOP several other implicit conversions 3870 * ... 3871 */ 3872 tnode_t * 3873 convert(op_t op, int arg, type_t *tp, tnode_t *tn) 3874 { 3875 tspec_t nt = tp->t_tspec; 3876 tspec_t ot = tn->tn_type->t_tspec; 3877 3878 if (allow_trad && allow_c90 && op == FARG) 3879 check_prototype_conversion(arg, nt, ot, tp, tn); 3880 3881 if (nt == BOOL) { 3882 /* No further checks. */ 3883 3884 } else if (is_integer(nt)) { 3885 if (ot == BOOL) { 3886 /* No further checks. */ 3887 } else if (is_integer(ot)) 3888 convert_integer_from_integer(op, arg, nt, ot, tp, tn); 3889 else if (is_floating(ot)) 3890 convert_integer_from_floating(op, arg, tp, tn); 3891 else if (ot == PTR) 3892 convert_integer_from_pointer(op, nt, tp, tn); 3893 3894 } else if (is_floating(nt)) { 3895 if (is_integer(ot) && op != CVT) { 3896 /* implicit conversion from integer '%s' to ... */ 3897 query_message(19, 3898 type_name(tn->tn_type), type_name(tp)); 3899 } 3900 3901 } else if (nt == PTR) { 3902 if (is_null_pointer(tn)) { 3903 /* a null pointer may be assigned to any pointer. */ 3904 } else if (ot == PTR && op == CVT) 3905 convert_pointer_from_pointer(tp, tn); 3906 } 3907 3908 tnode_t *ntn = expr_alloc_tnode(); 3909 ntn->tn_op = CVT; 3910 ntn->tn_type = tp; 3911 ntn->tn_cast = op == CVT; 3912 ntn->tn_sys |= tn->tn_sys; 3913 ntn->u.ops.right = NULL; 3914 if (tn->tn_op != CON || nt == VOID) { 3915 ntn->u.ops.left = tn; 3916 } else { 3917 ntn->tn_op = CON; 3918 convert_constant(op, arg, ntn->tn_type, &ntn->u.value, 3919 &tn->u.value); 3920 } 3921 3922 return ntn; 3923 } 3924 3925 static void 3926 convert_constant_from_floating(op_t op, int arg, const type_t *ntp, 3927 tspec_t nt, val_t *nv, val_t *ov) 3928 { 3929 long double max = 0.0, min = 0.0; 3930 3931 switch (nt) { 3932 case CHAR: 3933 max = TARG_CHAR_MAX; min = TARG_CHAR_MIN; break; 3934 case UCHAR: 3935 max = TARG_UCHAR_MAX; min = 0; break; 3936 case SCHAR: 3937 max = TARG_SCHAR_MAX; min = TARG_SCHAR_MIN; break; 3938 case SHORT: 3939 max = TARG_SHRT_MAX; min = TARG_SHRT_MIN; break; 3940 case USHORT: 3941 max = TARG_USHRT_MAX; min = 0; break; 3942 case ENUM: 3943 case INT: 3944 max = TARG_INT_MAX; min = TARG_INT_MIN; break; 3945 case UINT: 3946 max = TARG_UINT_MAX; min = 0; break; 3947 case LONG: 3948 max = TARG_LONG_MAX; min = TARG_LONG_MIN; break; 3949 case ULONG: 3950 max = TARG_ULONG_MAX; min = 0; break; 3951 case LLONG: 3952 max = LLONG_MAX; min = LLONG_MIN; break; 3953 case ULLONG: 3954 max = ULLONG_MAX; min = 0; break; 3955 case FLOAT: 3956 case FCOMPLEX: 3957 max = FLT_MAX; min = -FLT_MAX; break; 3958 case DOUBLE: 3959 case DCOMPLEX: 3960 max = DBL_MAX; min = -DBL_MAX; break; 3961 case LDOUBLE: 3962 case LCOMPLEX: 3963 /* LINTED 248; see floating_error_value. */ 3964 max = LDBL_MAX; min = -max; break; 3965 default: 3966 lint_assert(/*CONSTCOND*/false); 3967 } 3968 if (ov->u.floating > max || ov->u.floating < min) { 3969 lint_assert(nt != LDOUBLE); 3970 const char *ot_name = type_name(gettyp(ov->v_tspec)); 3971 const char *nt_name = type_name(ntp); 3972 if (is_integer(nt)) 3973 goto after_warning; 3974 if (op == FARG) 3975 /* conversion of '%s' to '%s' is out of range, ... */ 3976 warning(295, ot_name, nt_name, arg); 3977 else 3978 /* conversion of '%s' to '%s' is out of range */ 3979 warning(119, ot_name, nt_name); 3980 after_warning: 3981 ov->u.floating = ov->u.floating > 0 ? max : min; 3982 } 3983 3984 if (nt == FLOAT || nt == FCOMPLEX) 3985 nv->u.floating = (float)ov->u.floating; 3986 else if (nt == DOUBLE || nt == DCOMPLEX) 3987 nv->u.floating = (double)ov->u.floating; 3988 else if (nt == LDOUBLE || nt == LCOMPLEX) 3989 nv->u.floating = ov->u.floating; 3990 else 3991 nv->u.integer = (int64_t)ov->u.floating; 3992 } 3993 3994 static bool 3995 convert_constant_to_floating(tspec_t nt, val_t *nv, 3996 tspec_t ot, const val_t *v) 3997 { 3998 if (nt == FLOAT) { 3999 nv->u.floating = (ot == PTR || is_uinteger(ot)) ? 4000 (float)(uint64_t)v->u.integer : (float)v->u.integer; 4001 } else if (nt == DOUBLE) { 4002 nv->u.floating = (ot == PTR || is_uinteger(ot)) ? 4003 (double)(uint64_t)v->u.integer : (double)v->u.integer; 4004 } else if (nt == LDOUBLE) { 4005 nv->u.floating = (ot == PTR || is_uinteger(ot)) 4006 ? (long double)(uint64_t)v->u.integer 4007 : (long double)v->u.integer; 4008 } else 4009 return false; 4010 return true; 4011 } 4012 4013 /* 4014 * Print a warning if bits which were set are lost due to the conversion. 4015 * This can happen with operator ORASS only. 4016 */ 4017 static void 4018 convert_constant_check_range_bitor(size_t nsz, size_t osz, const val_t *v, 4019 uint64_t xmask, op_t op) 4020 { 4021 if (nsz < osz && (v->u.integer & xmask) != 0) 4022 /* constant truncated by conversion, op '%s' */ 4023 warning(306, op_name(op)); 4024 } 4025 4026 static void 4027 convert_constant_check_range_bitand(size_t nsz, size_t osz, 4028 uint64_t xmask, const val_t *nv, 4029 tspec_t ot, const val_t *v, 4030 const type_t *tp, op_t op) 4031 { 4032 if (nsz > osz && 4033 (nv->u.integer & bit((unsigned int)(osz - 1))) != 0 && 4034 (nv->u.integer & xmask) != xmask) { 4035 /* extra bits set to 0 in conversion of '%s' to '%s', ... */ 4036 warning(309, type_name(gettyp(ot)), 4037 type_name(tp), op_name(op)); 4038 } else if (nsz < osz && 4039 (v->u.integer & xmask) != xmask && 4040 (v->u.integer & xmask) != 0) 4041 /* constant truncated by conversion, op '%s' */ 4042 warning(306, op_name(op)); 4043 } 4044 4045 static void 4046 convert_constant_check_range_signed(op_t op, int arg, 4047 const type_t *ntp, int64_t ov) 4048 { 4049 if (op == ASSIGN) 4050 /* assignment of negative constant %lld to unsigned ... */ 4051 warning(164, (long long)ov, type_name(ntp)); 4052 else if (op == INIT) 4053 /* initialization of unsigned type '%s' with negative ... */ 4054 warning(221, type_name(ntp), (long long)ov); 4055 else if (op == FARG) 4056 /* conversion of negative constant %lld to unsigned ... */ 4057 warning(296, (long long)ov, type_name(ntp), arg); 4058 else if (modtab[op].m_comparison) { 4059 /* handled by check_integer_comparison() */ 4060 } else 4061 /* conversion of negative constant %lld to unsigned ... */ 4062 warning(222, (long long)ov, type_name(ntp)); 4063 } 4064 4065 /* 4066 * Loss of significant bit(s). All truncated bits of unsigned types or all 4067 * truncated bits plus the msb of the target for signed types are considered 4068 * to be significant bits. Loss of significant bits means that at least one 4069 * of the bits was set in an unsigned type or that at least one but not all 4070 * of the bits was set in a signed type. Loss of significant bits means that 4071 * it is not possible, also not with necessary casts, to convert back to the 4072 * original type. An example for a necessary cast is: 4073 * char c; int i; c = 128; 4074 * i = c; ** yields -128 ** 4075 * i = (unsigned char)c; ** yields 128 ** 4076 */ 4077 static void 4078 warn_constant_check_range_truncated(op_t op, int arg, const type_t *tp, 4079 tspec_t ot) 4080 { 4081 if (op == ASSIGN && tp->t_bitfield) 4082 /* precision lost in bit-field assignment */ 4083 warning(166); 4084 else if (op == ASSIGN) 4085 /* constant truncated by assignment */ 4086 warning(165); 4087 else if (op == INIT && tp->t_bitfield) 4088 /* bit-field initializer does not fit */ 4089 warning(180); 4090 else if (op == INIT) 4091 /* initializer does not fit */ 4092 warning(178); 4093 else if (op == CASE) 4094 /* case label affected by conversion */ 4095 warning(196); 4096 else if (op == FARG) 4097 /* conversion of '%s' to '%s' is out of range, arg #%d */ 4098 warning(295, type_name(gettyp(ot)), type_name(tp), arg); 4099 else 4100 /* conversion of '%s' to '%s' is out of range */ 4101 warning(119, type_name(gettyp(ot)), type_name(tp)); 4102 } 4103 4104 static void 4105 warn_constant_check_range_loss(op_t op, int arg, const type_t *tp, 4106 tspec_t ot) 4107 { 4108 if (op == ASSIGN && tp->t_bitfield) 4109 /* precision lost in bit-field assignment */ 4110 warning(166); 4111 else if (op == INIT && tp->t_bitfield) 4112 /* bit-field initializer out of range */ 4113 warning(11); 4114 else if (op == CASE) 4115 /* case label affected by conversion */ 4116 warning(196); 4117 else if (op == FARG) 4118 /* conversion of '%s' to '%s' is out of range, arg #%d */ 4119 warning(295, type_name(gettyp(ot)), type_name(tp), arg); 4120 else 4121 /* conversion of '%s' to '%s' is out of range */ 4122 warning(119, type_name(gettyp(ot)), type_name(tp)); 4123 } 4124 4125 static void 4126 convert_constant_check_range(tspec_t ot, const type_t *tp, tspec_t nt, 4127 op_t op, int arg, const val_t *v, val_t *nv) 4128 { 4129 unsigned int obitsz, nbitsz; 4130 uint64_t xmask, xmsk1; 4131 4132 obitsz = size_in_bits(ot); 4133 nbitsz = tp->t_bitfield ? tp->t_bit_field_width : size_in_bits(nt); 4134 xmask = value_bits(nbitsz) ^ value_bits(obitsz); 4135 xmsk1 = value_bits(nbitsz) ^ value_bits(obitsz - 1); 4136 if (op == ORASS || op == BITOR || op == BITXOR) { 4137 convert_constant_check_range_bitor( 4138 nbitsz, obitsz, v, xmask, op); 4139 } else if (op == ANDASS || op == BITAND) { 4140 convert_constant_check_range_bitand( 4141 nbitsz, obitsz, xmask, nv, ot, v, tp, op); 4142 } else if (nt != PTR && is_uinteger(nt) && 4143 ot != PTR && !is_uinteger(ot) && 4144 v->u.integer < 0) 4145 convert_constant_check_range_signed(op, arg, 4146 tp, v->u.integer); 4147 else if (nv->u.integer != v->u.integer && nbitsz <= obitsz && 4148 (v->u.integer & xmask) != 0 && 4149 (is_uinteger(ot) || (v->u.integer & xmsk1) != xmsk1)) 4150 warn_constant_check_range_truncated(op, arg, tp, ot); 4151 else if (nv->u.integer != v->u.integer) 4152 warn_constant_check_range_loss(op, arg, tp, ot); 4153 } 4154 4155 /* Converts a typed constant to a constant of another type. */ 4156 void 4157 convert_constant(op_t op, int arg, const type_t *ntp, val_t *nv, val_t *ov) 4158 { 4159 /* 4160 * TODO: make 'ov' const; the name of this function does not suggest 4161 * that it modifies 'ov'. 4162 */ 4163 tspec_t ot = ov->v_tspec; 4164 tspec_t nt = nv->v_tspec = ntp->t_tspec; 4165 bool range_check = false; 4166 4167 if (nt == BOOL) { /* C99 6.3.1.2 */ 4168 nv->v_unsigned_since_c90 = false; 4169 nv->u.integer = is_nonzero_val(ov) ? 1 : 0; 4170 return; 4171 } 4172 4173 if (ot == FLOAT || ot == DOUBLE || ot == LDOUBLE) 4174 convert_constant_from_floating(op, arg, ntp, nt, nv, ov); 4175 else if (!convert_constant_to_floating(nt, nv, ot, ov)) { 4176 range_check = true; /* Check for lost precision. */ 4177 nv->u.integer = ov->u.integer; 4178 } 4179 4180 if (allow_trad && allow_c90 && ov->v_unsigned_since_c90 && 4181 (is_floating(nt) || ( 4182 (is_integer(nt) && !is_uinteger(nt) && 4183 portable_rank_cmp(nt, ot) > 0)))) { 4184 /* C90 treats constant as unsigned */ 4185 warning(157); 4186 ov->v_unsigned_since_c90 = false; 4187 } 4188 4189 if (is_integer(nt)) { 4190 unsigned int size = ntp->t_bitfield 4191 ? ntp->t_bit_field_width : size_in_bits(nt); 4192 nv->u.integer = convert_integer(nv->u.integer, nt, size); 4193 } 4194 4195 if (range_check && op != CVT) 4196 convert_constant_check_range(ot, ntp, nt, op, arg, ov, nv); 4197 } 4198 4199 tnode_t * 4200 build_sizeof(const type_t *tp) 4201 { 4202 unsigned int size_in_bytes = type_size_in_bits(tp) / CHAR_SIZE; 4203 tnode_t *tn = build_integer_constant(SIZEOF_TSPEC, size_in_bytes); 4204 tn->tn_system_dependent = true; 4205 debug_step("build_sizeof '%s' = %u", type_name(tp), size_in_bytes); 4206 return tn; 4207 } 4208 4209 tnode_t * 4210 build_offsetof(const type_t *tp, designation dn) 4211 { 4212 unsigned int offset_in_bits = 0; 4213 4214 if (!is_struct_or_union(tp->t_tspec)) { 4215 /* unacceptable operand of '%s' */ 4216 error(111, "offsetof"); 4217 goto proceed; 4218 } 4219 for (size_t i = 0; i < dn.dn_len; i++) { 4220 const designator *dr = dn.dn_items + i; 4221 if (dr->dr_kind == DK_SUBSCRIPT) { 4222 if (tp->t_tspec != ARRAY) 4223 goto proceed; /* silent error */ 4224 tp = tp->t_subt; 4225 offset_in_bits += (unsigned)dr->dr_subscript 4226 * type_size_in_bits(tp); 4227 } else { 4228 if (!is_struct_or_union(tp->t_tspec)) 4229 goto proceed; /* silent error */ 4230 const char *name = dr->dr_member->s_name; 4231 sym_t *mem = find_member(tp->u.sou, name); 4232 if (mem == NULL) { 4233 /* type '%s' does not have member '%s' */ 4234 error(101, name, type_name(tp)); 4235 goto proceed; 4236 } 4237 tp = mem->s_type; 4238 offset_in_bits += mem->u.s_member.sm_offset_in_bits; 4239 } 4240 } 4241 free(dn.dn_items); 4242 4243 proceed:; 4244 unsigned int offset_in_bytes = offset_in_bits / CHAR_SIZE; 4245 tnode_t *tn = build_integer_constant(SIZEOF_TSPEC, offset_in_bytes); 4246 tn->tn_system_dependent = true; 4247 return tn; 4248 } 4249 4250 unsigned int 4251 type_size_in_bits(const type_t *tp) 4252 { 4253 4254 unsigned int elem = 1; 4255 bool flex = false; 4256 lint_assert(tp != NULL); 4257 while (tp->t_tspec == ARRAY) { 4258 flex = true; /* allow c99 flex arrays [] [0] */ 4259 elem *= tp->u.dimension; 4260 tp = tp->t_subt; 4261 } 4262 if (elem == 0 && !flex) { 4263 /* cannot take size/alignment of incomplete type */ 4264 error(143); 4265 elem = 1; 4266 } 4267 4268 unsigned int elsz; 4269 switch (tp->t_tspec) { 4270 case VOID: 4271 /* cannot take size/alignment of void */ 4272 error(146); 4273 elsz = 1; 4274 break; 4275 case FUNC: 4276 /* cannot take size/alignment of function type '%s' */ 4277 error(144, type_name(tp)); 4278 elsz = 1; 4279 break; 4280 case STRUCT: 4281 case UNION: 4282 if (is_incomplete(tp)) { 4283 /* cannot take size/alignment of incomplete type */ 4284 error(143); 4285 elsz = 1; 4286 } else 4287 elsz = tp->u.sou->sou_size_in_bits; 4288 break; 4289 case ENUM: 4290 if (is_incomplete(tp)) { 4291 /* cannot take size/alignment of incomplete type */ 4292 warning(143); 4293 } 4294 /* FALLTHROUGH */ 4295 default: 4296 if (tp->t_bitfield) 4297 /* cannot take size/alignment of bit-field */ 4298 error(145); 4299 elsz = size_in_bits(tp->t_tspec); 4300 lint_assert(elsz > 0); 4301 break; 4302 } 4303 4304 return elem * elsz; 4305 } 4306 4307 /* C11 6.5.3.4, GCC */ 4308 tnode_t * 4309 build_alignof(const type_t *tp) 4310 { 4311 if (tp->t_tspec == FUNC) { 4312 /* cannot take size/alignment of function type '%s' */ 4313 error(144, type_name(tp)); 4314 return NULL; 4315 } 4316 if (tp->t_tspec == VOID) { 4317 /* cannot take size/alignment of void */ 4318 error(146); 4319 return NULL; 4320 } 4321 if (is_incomplete(tp)) { 4322 /* cannot take size/alignment of incomplete type */ 4323 error(143); 4324 return NULL; 4325 } 4326 if (tp->t_bitfield) { 4327 /* cannot take size/alignment of bit-field */ 4328 error(145); 4329 return NULL; 4330 } 4331 return build_integer_constant(SIZEOF_TSPEC, (int64_t)alignment(tp)); 4332 } 4333 4334 static tnode_t * 4335 cast_to_union(tnode_t *otn, bool sys, type_t *ntp) 4336 { 4337 4338 if (!allow_gcc) { 4339 /* union cast is a GCC extension */ 4340 error(328); 4341 return NULL; 4342 } 4343 4344 for (const sym_t *m = ntp->u.sou->sou_first_member; 4345 m != NULL; m = m->s_next) { 4346 if (types_compatible(m->s_type, otn->tn_type, 4347 false, false, NULL)) { 4348 tnode_t *ntn = build_op(CVT, sys, ntp, otn, NULL); 4349 ntn->tn_cast = true; 4350 return ntn; 4351 } 4352 } 4353 4354 /* type '%s' is not a member of '%s' */ 4355 error(329, type_name(otn->tn_type), type_name(ntp)); 4356 return NULL; 4357 } 4358 4359 // In GCC mode, allow 'nullptr + offset' as a constant expression. 4360 static tnode_t * 4361 null_pointer_offset(tnode_t *tn) 4362 { 4363 uint64_t off = 0; 4364 const tnode_t *n = tn; 4365 while ((n->tn_op == PLUS || n->tn_op == MINUS) 4366 && is_integer(n->u.ops.right->tn_type->t_tspec)) { 4367 off += (uint64_t)n->u.ops.right->u.value.u.integer; 4368 n = n->u.ops.left; 4369 } 4370 if (n->tn_type->t_tspec == PTR 4371 && n->tn_op == ADDR 4372 && n->u.ops.left->tn_op == INDIR 4373 && n->u.ops.left->u.ops.left->tn_op == CON 4374 && n->u.ops.left->u.ops.left->tn_type->t_tspec == PTR) { 4375 off += (uint64_t)n->u.ops.left->u.ops.left->u.value.u.integer; 4376 return build_integer_constant(SIZEOF_TSPEC, (int64_t)off); 4377 } 4378 return tn; 4379 } 4380 4381 tnode_t * 4382 cast(tnode_t *tn, bool sys, type_t *tp) 4383 { 4384 4385 if (tn == NULL) 4386 return NULL; 4387 4388 tn = cconv(tn); 4389 4390 lint_assert(tp != NULL); 4391 tspec_t nt = tp->t_tspec; 4392 tspec_t ot = tn->tn_type->t_tspec; 4393 4394 if (nt == VOID) { 4395 /* 4396 * C90 6.3.4, C99 6.5.4p2 and C11 6.5.4p2 allow any type to be 4397 * cast to void. The only other allowed casts are from a 4398 * scalar type to a scalar type. 4399 */ 4400 } else if (nt == UNION) 4401 return cast_to_union(tn, sys, tp); 4402 else if (nt == STRUCT || nt == ARRAY || nt == FUNC) { 4403 /* Casting to a struct is an undocumented GCC extension. */ 4404 if (!(allow_gcc && nt == STRUCT)) 4405 goto invalid_cast; 4406 } else if (is_struct_or_union(ot)) 4407 goto invalid_cast; 4408 else if (ot == VOID) { 4409 /* improper cast of void expression */ 4410 error(148); 4411 return NULL; 4412 } else if (is_integer(nt) && is_scalar(ot)) { 4413 tn = null_pointer_offset(tn); 4414 } else if (is_floating(nt) && is_arithmetic(ot)) { 4415 /* ok */ 4416 } else if (nt == PTR && is_integer(ot)) { 4417 /* ok */ 4418 } else if (nt == PTR && ot == PTR) { 4419 if (!tp->t_subt->t_const && tn->tn_type->t_subt->t_const) { 4420 if (hflag) 4421 /* cast discards 'const' from type '%s' */ 4422 warning(275, type_name(tn->tn_type)); 4423 } 4424 } else 4425 goto invalid_cast; 4426 4427 if (any_query_enabled 4428 && types_compatible(tp, tn->tn_type, false, false, NULL)) 4429 /* no-op cast from '%s' to '%s' */ 4430 query_message(6, type_name(tn->tn_type), type_name(tp)); 4431 4432 tn = convert(CVT, 0, tp, tn); 4433 tn->tn_cast = true; 4434 tn->tn_sys = sys; 4435 4436 return tn; 4437 4438 invalid_cast: 4439 /* invalid cast from '%s' to '%s' */ 4440 error(147, type_name(tn->tn_type), type_name(tp)); 4441 return NULL; 4442 } 4443 4444 void 4445 add_function_argument(function_call *call, tnode_t *arg) 4446 { 4447 /* 4448 * If there was a serious error in the expression for the argument, 4449 * create a dummy argument so the positions of the remaining arguments 4450 * will not change. 4451 */ 4452 if (arg == NULL) 4453 arg = build_integer_constant(INT, 0); 4454 4455 if (call->args_len >= call->args_cap) { 4456 call->args_cap += 8; 4457 tnode_t **new_args = expr_zero_alloc( 4458 call->args_cap * sizeof(*call->args), "tnode*[]"); 4459 if (call->args_len > 0) 4460 memcpy(new_args, call->args, 4461 call->args_len * sizeof(*call->args)); 4462 call->args = new_args; 4463 } 4464 call->args[call->args_len++] = arg; 4465 } 4466 4467 /* 4468 * Compare the type of an argument with the corresponding type of a 4469 * prototype parameter. If it is a valid combination, but both types 4470 * are not the same, insert a conversion to convert the argument into 4471 * the type of the parameter. 4472 */ 4473 static tnode_t * 4474 check_prototype_argument( 4475 int n, /* pos of arg */ 4476 type_t *tp, /* expected type (from prototype) */ 4477 tnode_t *tn) /* argument */ 4478 { 4479 tnode_t *ln = xcalloc(1, sizeof(*ln)); 4480 ln->tn_type = expr_unqualified_type(tp); 4481 ln->tn_lvalue = true; 4482 if (typeok(FARG, n, ln, tn)) { 4483 bool dowarn; 4484 if (!types_compatible(tp, tn->tn_type, 4485 true, false, (dowarn = false, &dowarn)) || dowarn) 4486 tn = convert(FARG, n, tp, tn); 4487 } 4488 free(ln); 4489 return tn; 4490 } 4491 4492 /* 4493 * Check types of all function arguments and insert conversions, 4494 * if necessary. 4495 */ 4496 static void 4497 check_function_arguments(const function_call *call) 4498 { 4499 type_t *ftp = call->func->tn_type->t_subt; 4500 4501 /* get # of parameters in the prototype */ 4502 int npar = 0; 4503 for (const sym_t *p = ftp->u.params; p != NULL; p = p->s_next) 4504 npar++; 4505 4506 int narg = (int)call->args_len; 4507 4508 const sym_t *param = ftp->u.params; 4509 if (ftp->t_proto && npar != narg && !(ftp->t_vararg && npar < narg)) { 4510 /* argument mismatch: %d %s passed, %d expected */ 4511 error(150, narg, narg != 1 ? "arguments" : "argument", npar); 4512 param = NULL; 4513 } 4514 4515 for (int i = 0; i < narg; i++) { 4516 tnode_t *arg = call->args[i]; 4517 4518 /* some things which are always not allowed */ 4519 tspec_t at = arg->tn_type->t_tspec; 4520 if (at == VOID) { 4521 /* void expressions may not be arguments, arg #%d */ 4522 error(151, i + 1); 4523 return; 4524 } 4525 if (is_struct_or_union(at) && is_incomplete(arg->tn_type)) { 4526 /* argument cannot have unknown size, arg #%d */ 4527 error(152, i + 1); 4528 return; 4529 } 4530 if (is_integer(at) && 4531 arg->tn_type->t_is_enum && 4532 is_incomplete(arg->tn_type)) { 4533 /* argument cannot have unknown size, arg #%d */ 4534 warning(152, i + 1); 4535 } 4536 4537 arg = cconv(arg); 4538 call->args[i] = arg; 4539 4540 arg = param != NULL 4541 ? check_prototype_argument(i + 1, param->s_type, arg) 4542 : promote(NOOP, true, arg); 4543 call->args[i] = arg; 4544 4545 if (param != NULL) 4546 param = param->s_next; 4547 } 4548 } 4549 4550 tnode_t * 4551 build_function_call(tnode_t *func, bool sys, function_call *call) 4552 { 4553 4554 if (func == NULL) 4555 return NULL; 4556 4557 call->func = func; 4558 check_ctype_function_call(call); 4559 4560 func = cconv(func); 4561 call->func = func; 4562 4563 if (func->tn_type->t_tspec != PTR || 4564 func->tn_type->t_subt->t_tspec != FUNC) { 4565 /* cannot call '%s', must be a function */ 4566 error(149, type_name(func->tn_type)); 4567 return NULL; 4568 } 4569 4570 check_function_arguments(call); 4571 4572 tnode_t *ntn = expr_alloc_tnode(); 4573 ntn->tn_op = CALL; 4574 ntn->tn_type = func->tn_type->t_subt->t_subt; 4575 ntn->tn_sys = sys; 4576 ntn->u.call = call; 4577 return ntn; 4578 } 4579 4580 /* 4581 * Return the value of an integral constant expression. 4582 * If the expression is not constant or its type is not an integer 4583 * type, an error message is printed. 4584 */ 4585 val_t * 4586 integer_constant(tnode_t *tn, bool required) 4587 { 4588 4589 if (tn != NULL) 4590 tn = cconv(tn); 4591 if (tn != NULL) 4592 tn = promote(NOOP, false, tn); 4593 4594 val_t *v = xcalloc(1, sizeof(*v)); 4595 4596 if (tn == NULL) { 4597 lint_assert(seen_error); 4598 debug_step("constant node is null; returning 1 instead"); 4599 v->v_tspec = INT; 4600 v->u.integer = 1; 4601 return v; 4602 } 4603 4604 v->v_tspec = tn->tn_type->t_tspec; 4605 4606 if (tn->tn_op == CON) { 4607 lint_assert(tn->tn_type->t_tspec == tn->u.value.v_tspec); 4608 if (is_integer(tn->u.value.v_tspec)) { 4609 v->v_unsigned_since_c90 = 4610 tn->u.value.v_unsigned_since_c90; 4611 v->u.integer = tn->u.value.u.integer; 4612 return v; 4613 } 4614 v->u.integer = (int64_t)tn->u.value.u.floating; 4615 } else 4616 v->u.integer = 1; 4617 4618 if (required) 4619 /* integral constant expression expected */ 4620 error(55); 4621 else 4622 /* variable array dimension is a C99/GCC extension */ 4623 c99ism(318); 4624 4625 if (!is_integer(v->v_tspec)) 4626 v->v_tspec = INT; 4627 4628 return v; 4629 } 4630 4631 static bool 4632 is_constcond_false(const tnode_t *tn, tspec_t t) 4633 { 4634 return (t == BOOL || t == INT) && 4635 tn->tn_op == CON && tn->u.value.u.integer == 0; 4636 } 4637 4638 /* 4639 * Perform some tests on expressions which can't be done in build_binary() 4640 * and functions called by build_binary(). These tests must be done here 4641 * because we need some information about the context in which the operations 4642 * are performed. 4643 * After all tests are performed and dofreeblk is true, expr() frees the 4644 * memory which is used for the expression. 4645 */ 4646 void 4647 expr(tnode_t *tn, bool vctx, bool cond, bool dofreeblk, bool is_do_while, 4648 const char *stmt_kind) 4649 { 4650 4651 if (tn == NULL) { /* in case of errors */ 4652 expr_free_all(); 4653 return; 4654 } 4655 4656 /* expr() is also called in global initializations */ 4657 if (dcs->d_kind != DLK_EXTERN && !is_do_while) 4658 check_statement_reachable(stmt_kind); 4659 4660 check_expr_misc(tn, vctx, cond, !cond, false, false, false); 4661 if (tn->tn_op == ASSIGN && !tn->tn_parenthesized) { 4662 if (hflag && cond) 4663 /* assignment in conditional context */ 4664 warning(159); 4665 } else if (tn->tn_op == CON) { 4666 if (hflag && cond && !suppress_constcond && 4667 !tn->tn_system_dependent && 4668 !(is_do_while && 4669 is_constcond_false(tn, tn->tn_type->t_tspec))) 4670 /* constant in conditional context */ 4671 warning(161); 4672 } 4673 if (!modtab[tn->tn_op].m_has_side_effect) { 4674 /* 4675 * for left operands of COMMA this warning is already printed 4676 */ 4677 if (tn->tn_op != COMMA && !vctx && !cond) 4678 check_null_effect(tn); 4679 } 4680 debug_node(tn); 4681 4682 if (dofreeblk) 4683 expr_free_all(); 4684 } 4685 4686 /* If the expression has the form '*(arr + idx)', check the array index. */ 4687 static void 4688 check_array_index(const tnode_t *indir, bool taking_address) 4689 { 4690 const tnode_t *plus, *arr, *idx; 4691 4692 if (indir->tn_op == INDIR 4693 && (plus = indir->u.ops.left, plus->tn_op == PLUS) 4694 && plus->u.ops.left->tn_op == ADDR 4695 && (arr = plus->u.ops.left->u.ops.left, true) 4696 && (arr->tn_op == STRING || arr->tn_op == NAME) 4697 && arr->tn_type->t_tspec == ARRAY 4698 && (idx = plus->u.ops.right, idx->tn_op == CON) 4699 && (!is_incomplete(arr->tn_type) || idx->u.value.u.integer < 0)) 4700 goto proceed; 4701 return; 4702 4703 proceed:; 4704 int elsz = length_in_bits(arr->tn_type->t_subt, NULL); 4705 if (elsz == 0) 4706 return; 4707 elsz /= CHAR_SIZE; 4708 4709 /* Change the unit of the index from bytes to element size. */ 4710 int64_t con = is_uinteger(idx->tn_type->t_tspec) 4711 ? (int64_t)((uint64_t)idx->u.value.u.integer / elsz) 4712 : idx->u.value.u.integer / elsz; 4713 4714 int dim = arr->tn_type->u.dimension + (taking_address ? 1 : 0); 4715 4716 if (!is_uinteger(idx->tn_type->t_tspec) && con < 0) 4717 /* array subscript %jd cannot be negative */ 4718 warning(167, (intmax_t)con); 4719 else if (dim > 0 && (uint64_t)con >= (uint64_t)dim) 4720 /* array subscript %ju cannot be > %d */ 4721 warning(168, (uintmax_t)con, dim - 1); 4722 } 4723 4724 static void 4725 check_expr_addr(const tnode_t *ln, bool szof, bool fcall) 4726 { 4727 /* XXX: Taking warn_about_unreachable into account here feels wrong. */ 4728 if (ln->tn_op == NAME && (reached || !warn_about_unreachable)) { 4729 if (!szof) 4730 mark_as_set(ln->u.sym); 4731 mark_as_used(ln->u.sym, fcall, szof); 4732 } 4733 check_array_index(ln, true); 4734 } 4735 4736 /* 4737 * If there is an asm statement in one of the compound statements around, 4738 * there may be other side effects, so don't warn. 4739 */ 4740 static bool 4741 is_asm_around(void) 4742 { 4743 for (decl_level *dl = dcs; dl != NULL; dl = dl->d_enclosing) 4744 if (dl->d_asm) 4745 return true; 4746 return false; 4747 } 4748 4749 static void 4750 check_expr_side_effect(const tnode_t *ln, bool szof) 4751 { 4752 4753 /* XXX: Taking warn_about_unreachable into account here feels wrong. */ 4754 if (ln->tn_op == NAME && (reached || !warn_about_unreachable)) { 4755 scl_t sc = ln->u.sym->s_scl; 4756 if (sc != EXTERN && sc != STATIC && 4757 !ln->u.sym->s_set && !szof && !is_asm_around()) { 4758 /* '%s' may be used before set */ 4759 warning(158, ln->u.sym->s_name); 4760 mark_as_set(ln->u.sym); 4761 } 4762 mark_as_used(ln->u.sym, false, false); 4763 } 4764 } 4765 4766 static void 4767 check_expr_assign(const tnode_t *ln, bool szof) 4768 { 4769 /* XXX: Taking warn_about_unreachable into account here feels wrong. */ 4770 if (ln->tn_op == NAME && !szof && (reached || !warn_about_unreachable)) { 4771 mark_as_set(ln->u.sym); 4772 if (ln->u.sym->s_scl == EXTERN) 4773 outusg(ln->u.sym); 4774 } 4775 check_array_index(ln, false); 4776 } 4777 4778 static void 4779 check_expr_call(const tnode_t *tn, const tnode_t *ln, 4780 bool szof, bool vctx, bool cond, bool retval_discarded) 4781 { 4782 lint_assert(ln->tn_op == ADDR); 4783 lint_assert(ln->u.ops.left->tn_op == NAME); 4784 if (!szof && !is_compiler_builtin(ln->u.ops.left->u.sym->s_name)) 4785 outcall(tn, vctx || cond, retval_discarded); 4786 4787 const function_call *call = tn->u.call; 4788 if (call->args_len == 4 || call->args_len == 5) 4789 check_snprintb(call); 4790 } 4791 4792 static void 4793 check_expr_op(op_t op, const tnode_t *ln, bool szof, bool fcall, bool eqwarn) 4794 { 4795 switch (op) { 4796 case ADDR: 4797 check_expr_addr(ln, szof, fcall); 4798 break; 4799 case LOAD: 4800 check_array_index(ln, false); 4801 /* FALLTHROUGH */ 4802 case INCBEF: 4803 case DECBEF: 4804 case INCAFT: 4805 case DECAFT: 4806 case ADDASS: 4807 case SUBASS: 4808 case MULASS: 4809 case DIVASS: 4810 case MODASS: 4811 case ANDASS: 4812 case ORASS: 4813 case XORASS: 4814 case SHLASS: 4815 case SHRASS: 4816 case REAL: 4817 case IMAG: 4818 check_expr_side_effect(ln, szof); 4819 break; 4820 case ASSIGN: 4821 check_expr_assign(ln, szof); 4822 break; 4823 case EQ: 4824 if (hflag && eqwarn) 4825 /* operator '==' found where '=' was expected */ 4826 warning(160); 4827 break; 4828 default: 4829 break; 4830 } 4831 } 4832 4833 /* 4834 * vctx ??? 4835 * cond whether the expression is a condition that 4836 * will be compared with 0 4837 * eqwarn whether the operator '==' might be a 4838 * misspelled '=' 4839 * fcall whether the expression is a function call 4840 * retval_discarded whether the return value of a function call 4841 * is discarded; such calls will be analyzed by 4842 * lint2 in messages 4, 8 and 9 4843 * szof whether the expression is part of a sizeof 4844 * expression, which means that its value is 4845 * discarded since only the type is relevant 4846 */ 4847 void 4848 check_expr_misc(const tnode_t *tn, bool vctx, bool cond, 4849 bool eqwarn, bool fcall, bool retval_discarded, bool szof) 4850 { 4851 4852 if (tn == NULL) 4853 return; 4854 op_t op = tn->tn_op; 4855 if (op == NAME || op == CON || op == STRING) 4856 return; 4857 bool is_direct = op == CALL 4858 && tn->u.call->func->tn_op == ADDR 4859 && tn->u.call->func->u.ops.left->tn_op == NAME; 4860 if (op == CALL) { 4861 const function_call *call = tn->u.call; 4862 if (is_direct) 4863 check_expr_call(tn, call->func, 4864 szof, vctx, cond, retval_discarded); 4865 bool discard = op == CVT && tn->tn_type->t_tspec == VOID; 4866 check_expr_misc(call->func, false, false, false, is_direct, 4867 discard, szof); 4868 for (size_t i = 0, n = call->args_len; i < n; i++) 4869 check_expr_misc(call->args[i], 4870 true, false, false, false, false, szof); 4871 return; 4872 } 4873 4874 lint_assert(has_operands(tn)); 4875 tnode_t *ln = tn->u.ops.left; 4876 tnode_t *rn = tn->u.ops.right; 4877 check_expr_op(op, ln, szof, fcall, eqwarn); 4878 4879 const mod_t *mp = &modtab[op]; 4880 bool cvctx = mp->m_value_context; 4881 bool ccond = mp->m_compares_with_zero; 4882 bool eq = mp->m_warn_if_operand_eq && 4883 !ln->tn_parenthesized && 4884 rn != NULL && !rn->tn_parenthesized; 4885 4886 /* 4887 * Values of operands of ':' are not used if the type of at least 4888 * one of the operands (for GCC compatibility) is 'void'. 4889 * 4890 * XXX test/value context of QUEST should probably be used as 4891 * context for both operands of COLON. 4892 */ 4893 if (op == COLON && tn->tn_type->t_tspec == VOID) 4894 cvctx = ccond = false; 4895 bool discard = op == CVT && tn->tn_type->t_tspec == VOID; 4896 check_expr_misc(ln, cvctx, ccond, eq, is_direct, discard, szof); 4897 4898 switch (op) { 4899 case LOGAND: 4900 case LOGOR: 4901 check_expr_misc(rn, false, true, eq, false, false, szof); 4902 break; 4903 case COLON: 4904 check_expr_misc(rn, cvctx, ccond, eq, false, false, szof); 4905 break; 4906 case COMMA: 4907 check_expr_misc(rn, vctx, cond, false, false, false, szof); 4908 break; 4909 default: 4910 if (mp->m_binary) 4911 check_expr_misc(rn, true, false, eq, false, false, 4912 szof); 4913 break; 4914 } 4915 } 4916 4917 /* 4918 * Return whether the expression can be used for static initialization. 4919 * 4920 * Constant initialization expressions must be constant or an address 4921 * of a static object with an optional offset. In the first case, 4922 * the result is returned in *offsp. In the second case, the static 4923 * object is returned in *symp and the offset in *offsp. 4924 * 4925 * The expression can consist of PLUS, MINUS, ADDR, NAME, STRING and 4926 * CON. Type conversions are allowed if they do not change binary 4927 * representation (including width). 4928 * 4929 * C99 6.6 "Constant expressions" 4930 * C99 6.7.8p4 restricts initializers for static storage duration 4931 */ 4932 bool 4933 constant_addr(const tnode_t *tn, const sym_t **symp, ptrdiff_t *offsp) 4934 { 4935 const sym_t *sym; 4936 ptrdiff_t offs1, offs2; 4937 tspec_t t, ot; 4938 4939 switch (tn->tn_op) { 4940 case MINUS: 4941 if (tn->u.ops.right->tn_op == CVT) 4942 return constant_addr(tn->u.ops.right, symp, offsp); 4943 else if (tn->u.ops.right->tn_op != CON) 4944 return false; 4945 /* FALLTHROUGH */ 4946 case PLUS: 4947 offs1 = offs2 = 0; 4948 if (tn->u.ops.left->tn_op == CON) { 4949 offs1 = (ptrdiff_t)tn->u.ops.left->u.value.u.integer; 4950 if (!constant_addr(tn->u.ops.right, &sym, &offs2)) 4951 return false; 4952 } else if (tn->u.ops.right->tn_op == CON) { 4953 offs2 = (ptrdiff_t)tn->u.ops.right->u.value.u.integer; 4954 if (tn->tn_op == MINUS) 4955 offs2 = -offs2; 4956 if (!constant_addr(tn->u.ops.left, &sym, &offs1)) 4957 return false; 4958 } else { 4959 return false; 4960 } 4961 *symp = sym; 4962 *offsp = offs1 + offs2; 4963 return true; 4964 case ADDR: 4965 if (tn->u.ops.left->tn_op == NAME) { 4966 *symp = tn->u.ops.left->u.sym; 4967 *offsp = 0; 4968 return true; 4969 } else { 4970 /* 4971 * If this were the front end of a compiler, we would 4972 * return a label instead of 0, at least if 4973 * 'tn->u.ops.left->tn_op == STRING'. 4974 */ 4975 *symp = NULL; 4976 *offsp = 0; 4977 return true; 4978 } 4979 case CVT: 4980 t = tn->tn_type->t_tspec; 4981 ot = tn->u.ops.left->tn_type->t_tspec; 4982 if ((!is_integer(t) && t != PTR) || 4983 (!is_integer(ot) && ot != PTR)) { 4984 return false; 4985 } 4986 #if 0 4987 /*- 4988 * consider: 4989 * struct foo { 4990 * unsigned char a; 4991 * } f = { 4992 * (unsigned char)(unsigned long) 4993 * (&(((struct foo *)0)->a)) 4994 * }; 4995 * since psize(unsigned long) != psize(unsigned char), 4996 * this fails. 4997 */ 4998 else if (psize(t) != psize(ot)) 4999 return -1; 5000 #endif 5001 return constant_addr(tn->u.ops.left, symp, offsp); 5002 default: 5003 return false; 5004 } 5005 } 5006 5007 /* Append s2 to s1, then free s2. */ 5008 buffer * 5009 cat_strings(buffer *s1, buffer *s2) 5010 { 5011 5012 if ((s1->data != NULL) != (s2->data != NULL)) { 5013 /* cannot concatenate wide and regular string literals */ 5014 error(292); 5015 return s1; 5016 } 5017 5018 if (s1->data != NULL) { 5019 while (s1->len + s2->len + 1 > s1->cap) 5020 s1->cap *= 2; 5021 s1->data = xrealloc(s1->data, s1->cap); 5022 memcpy(s1->data + s1->len, s2->data, s2->len + 1); 5023 free(s2->data); 5024 } 5025 s1->len += s2->len; 5026 free(s2); 5027 5028 return s1; 5029 } 5030 5031 5032 typedef struct stmt_expr { 5033 memory_pool se_mem; 5034 sym_t *se_sym; 5035 struct stmt_expr *se_enclosing; 5036 } stmt_expr; 5037 5038 static stmt_expr *stmt_exprs; 5039 5040 void 5041 begin_statement_expr(void) 5042 { 5043 debug_enter(); 5044 5045 stmt_expr *se = xmalloc(sizeof(*se)); 5046 se->se_mem = expr_save_memory(); 5047 se->se_sym = NULL; 5048 se->se_enclosing = stmt_exprs; 5049 stmt_exprs = se; 5050 } 5051 5052 void 5053 do_statement_expr(tnode_t *tn) 5054 { 5055 block_level--; 5056 mem_block_level--; 5057 stmt_exprs->se_sym = tn != NULL 5058 ? mktempsym(block_dup_type(tn->tn_type)) 5059 : NULL; /* after a syntax error */ 5060 mem_block_level++; 5061 block_level++; 5062 /* '({ ... })' is a GCC extension */ 5063 gnuism(320); 5064 } 5065 5066 tnode_t * 5067 end_statement_expr(void) 5068 { 5069 tnode_t *tn; 5070 5071 stmt_expr *se = stmt_exprs; 5072 if (se->se_sym == NULL) { 5073 tn = NULL; /* after a syntax error */ 5074 goto end; 5075 } 5076 5077 tn = build_name(se->se_sym, false); 5078 (void)expr_save_memory(); /* leak */ 5079 expr_restore_memory(se->se_mem); 5080 stmt_exprs = se->se_enclosing; 5081 free(se); 5082 5083 end: 5084 debug_leave(); 5085 return tn; 5086 } 5087 5088 bool 5089 in_statement_expr(void) 5090 { 5091 return stmt_exprs != NULL; 5092 } 5093
Indexes created Mon Sep 22 21:09:42 GMT 2025