tree.c revision 1.664
1 /* $NetBSD: tree.c,v 1.664 2024/12/15 06:04:17 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 1.664 2024/12/15 06:04:17 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 uint64_t 81 u64_max(uint64_t a, uint64_t b) 82 { 83 return a > b ? a : b; 84 } 85 86 static uint64_t 87 u64_fill_right(uint64_t x) 88 { 89 x |= x >> 1; 90 x |= x >> 2; 91 x |= x >> 4; 92 x |= x >> 8; 93 x |= x >> 16; 94 x |= x >> 32; 95 return x; 96 } 97 98 static bool 99 str_ends_with(const char *haystack, const char *needle) 100 { 101 size_t hlen = strlen(haystack); 102 size_t nlen = strlen(needle); 103 104 return nlen <= hlen && 105 memcmp(haystack + hlen - nlen, needle, nlen) == 0; 106 } 107 108 static unsigned 109 width_in_bits(const type_t *tp) 110 { 111 112 lint_assert(is_integer(tp->t_tspec)); 113 return tp->t_bitfield 114 ? tp->t_bit_field_width 115 : size_in_bits(tp->t_tspec); 116 } 117 118 static int 119 portable_rank_cmp(tspec_t t1, tspec_t t2) 120 { 121 const ttab_t *p1 = type_properties(t1), *p2 = type_properties(t2); 122 lint_assert(p1->tt_rank_kind == p2->tt_rank_kind); 123 lint_assert(p1->tt_rank_value > 0); 124 lint_assert(p2->tt_rank_value > 0); 125 return (int)p1->tt_rank_value - (int)p2->tt_rank_value; 126 } 127 128 static bool 129 ic_maybe_signed(const type_t *tp, const integer_constraints *ic) 130 { 131 return !is_uinteger(tp->t_tspec) && ic->bclr >> 63 == 0; 132 } 133 134 static integer_constraints 135 ic_any(const type_t *tp) 136 { 137 integer_constraints c; 138 139 uint64_t vbits = value_bits(width_in_bits(tp)); 140 if (is_uinteger(tp->t_tspec)) { 141 c.smin = INT64_MIN; 142 c.smax = INT64_MAX; 143 c.umin = 0; 144 c.umax = vbits; 145 c.bclr = ~c.umax; 146 } else { 147 c.smin = (int64_t)-1 - (int64_t)(vbits >> 1); 148 c.smax = (int64_t)(vbits >> 1); 149 c.umin = 0; 150 c.umax = UINT64_MAX; 151 c.bclr = 0; 152 } 153 return c; 154 } 155 156 static integer_constraints 157 ic_mult(const type_t *tp, integer_constraints a, integer_constraints b) 158 { 159 integer_constraints c; 160 161 if (ic_maybe_signed(tp, &a) || ic_maybe_signed(tp, &b) 162 || (a.umax > 0 && b.umax > ic_any(tp).umax / a.umax)) 163 return ic_any(tp); 164 165 c.smin = INT64_MIN; 166 c.smax = INT64_MAX; 167 c.umin = a.umin * b.umin; 168 c.umax = a.umax * b.umax; 169 c.bclr = ~u64_fill_right(c.umax); 170 return c; 171 } 172 173 static integer_constraints 174 ic_div(const type_t *tp, integer_constraints a, integer_constraints b) 175 { 176 integer_constraints c; 177 178 if (ic_maybe_signed(tp, &a) || ic_maybe_signed(tp, &b) || b.umin == 0) 179 return ic_any(tp); 180 181 c.smin = INT64_MIN; 182 c.smax = INT64_MAX; 183 c.umin = a.umin / b.umax; 184 c.umax = a.umax / b.umin; 185 c.bclr = ~u64_fill_right(c.umax); 186 return c; 187 } 188 189 static integer_constraints 190 ic_mod_signed(integer_constraints a, integer_constraints b) 191 { 192 integer_constraints c; 193 194 uint64_t max_abs_b = u64_max(s64_abs(b.smin), s64_abs(b.smax)); 195 if (max_abs_b >> 63 != 0 || max_abs_b == 0) 196 return a; 197 c.smin = s64_max(a.smin, -(int64_t)(max_abs_b - 1)); 198 c.smax = s64_min(a.smax, (int64_t)(max_abs_b - 1)); 199 c.umin = 0; 200 c.umax = UINT64_MAX; 201 c.bclr = 0; 202 return c; 203 } 204 205 static integer_constraints 206 ic_mod(const type_t *tp, integer_constraints a, integer_constraints b) 207 { 208 integer_constraints c; 209 210 if (ic_maybe_signed(tp, &a) || ic_maybe_signed(tp, &b)) 211 return ic_mod_signed(a, b); 212 213 c.smin = INT64_MIN; 214 c.smax = INT64_MAX; 215 c.umin = 0; 216 c.umax = b.umax - 1; 217 c.bclr = ~u64_fill_right(c.umax); 218 return c; 219 } 220 221 static integer_constraints 222 ic_shl(const type_t *tp, integer_constraints a, integer_constraints b) 223 { 224 integer_constraints c; 225 unsigned int amount; 226 227 if (ic_maybe_signed(tp, &a)) 228 return ic_any(tp); 229 230 if (b.smin == b.smax && b.smin >= 0 && b.smin < 64) 231 amount = (unsigned int)b.smin; 232 else if (b.umin == b.umax && b.umin < 64) 233 amount = (unsigned int)b.umin; 234 else 235 return ic_any(tp); 236 237 c.smin = INT64_MIN; 238 c.smax = INT64_MAX; 239 c.umin = 0; 240 c.umax = UINT64_MAX; 241 c.bclr = a.bclr << amount | (((uint64_t)1 << amount) - 1); 242 return c; 243 } 244 245 static integer_constraints 246 ic_shr(const type_t *tp, integer_constraints a, integer_constraints b) 247 { 248 integer_constraints c; 249 unsigned int amount; 250 251 if (ic_maybe_signed(tp, &a)) 252 return ic_any(tp); 253 254 if (b.smin == b.smax && b.smin >= 0 && b.smin < 64) 255 amount = (unsigned int)b.smin; 256 else if (b.umin == b.umax && b.umin < 64) 257 amount = (unsigned int)b.umin; 258 else 259 return ic_any(tp); 260 261 c.smin = INT64_MIN; 262 c.smax = INT64_MAX; 263 c.umin = 0; 264 c.umax = UINT64_MAX; 265 c.bclr = a.bclr >> amount | ~(~(uint64_t)0 >> amount); 266 return c; 267 } 268 269 static integer_constraints 270 ic_bitand(integer_constraints a, integer_constraints b) 271 { 272 integer_constraints c; 273 274 c.smin = INT64_MIN; 275 c.smax = INT64_MAX; 276 c.umin = 0; 277 c.umax = ~(a.bclr | b.bclr); 278 if (c.umax >> 63 == 0) { 279 c.smin = 0; 280 c.smax = (int64_t)c.umax; 281 } 282 c.bclr = a.bclr | b.bclr; 283 return c; 284 } 285 286 static integer_constraints 287 ic_bitor(integer_constraints a, integer_constraints b) 288 { 289 integer_constraints c; 290 291 c.smin = INT64_MIN; 292 c.smax = INT64_MAX; 293 c.umin = 0; 294 c.umax = ~(a.bclr & b.bclr); 295 c.bclr = a.bclr & b.bclr; 296 return c; 297 } 298 299 static integer_constraints 300 ic_quest_colon(integer_constraints a, integer_constraints b) 301 { 302 integer_constraints c; 303 304 c.smin = a.smin < b.smin ? a.smin : b.smin; 305 c.smax = a.smax > b.smax ? a.smax : b.smax; 306 c.umin = a.umin < b.umin ? a.umin : b.umin; 307 c.umax = a.umax > b.umax ? a.umax : b.umax; 308 c.bclr = a.bclr & b.bclr; 309 return c; 310 } 311 312 static integer_constraints 313 ic_con(const type_t *tp, const val_t *v) 314 { 315 integer_constraints c; 316 317 lint_assert(is_integer(tp->t_tspec)); 318 int64_t si = v->u.integer; 319 uint64_t ui = (uint64_t)si; 320 c.smin = si; 321 c.smax = si; 322 c.umin = ui; 323 c.umax = ui; 324 c.bclr = ~ui; 325 return c; 326 } 327 328 static integer_constraints 329 ic_cvt(const type_t *ntp, const type_t *otp, integer_constraints a) 330 { 331 unsigned nw = width_in_bits(ntp); 332 unsigned ow = width_in_bits(otp); 333 bool nu = is_uinteger(ntp->t_tspec); 334 bool ou = is_uinteger(otp->t_tspec); 335 336 if (nw >= ow && nu == ou) 337 return a; 338 if (nw > ow && ou) 339 return a; 340 return ic_any(ntp); 341 } 342 343 static integer_constraints 344 ic_expr(const tnode_t *tn) 345 { 346 integer_constraints lc, rc; 347 348 lint_assert(is_integer(tn->tn_type->t_tspec)); 349 350 switch (tn->tn_op) { 351 case MULT: 352 lc = ic_expr(before_conversion(tn->u.ops.left)); 353 rc = ic_expr(before_conversion(tn->u.ops.right)); 354 return ic_mult(tn->tn_type, lc, rc); 355 case DIV: 356 lc = ic_expr(before_conversion(tn->u.ops.left)); 357 rc = ic_expr(before_conversion(tn->u.ops.right)); 358 return ic_div(tn->tn_type, lc, rc); 359 case MOD: 360 lc = ic_expr(before_conversion(tn->u.ops.left)); 361 rc = ic_expr(before_conversion(tn->u.ops.right)); 362 return ic_mod(tn->tn_type, lc, rc); 363 case SHL: 364 lc = ic_expr(tn->u.ops.left); 365 rc = ic_expr(tn->u.ops.right); 366 return ic_shl(tn->tn_type, lc, rc); 367 case SHR: 368 lc = ic_expr(tn->u.ops.left); 369 rc = ic_expr(tn->u.ops.right); 370 return ic_shr(tn->tn_type, lc, rc); 371 case BITAND: 372 lc = ic_expr(tn->u.ops.left); 373 rc = ic_expr(tn->u.ops.right); 374 return ic_bitand(lc, rc); 375 case BITOR: 376 lc = ic_expr(tn->u.ops.left); 377 rc = ic_expr(tn->u.ops.right); 378 return ic_bitor(lc, rc); 379 case QUEST: 380 lc = ic_expr(tn->u.ops.right->u.ops.left); 381 rc = ic_expr(tn->u.ops.right->u.ops.right); 382 return ic_quest_colon(lc, rc); 383 case CON: 384 return ic_con(tn->tn_type, &tn->u.value); 385 case CVT: 386 if (!is_integer(tn->u.ops.left->tn_type->t_tspec)) 387 return ic_any(tn->tn_type); 388 lc = ic_expr(tn->u.ops.left); 389 return ic_cvt(tn->tn_type, tn->u.ops.left->tn_type, lc); 390 default: 391 return ic_any(tn->tn_type); 392 } 393 } 394 395 uint64_t 396 possible_bits(const tnode_t *tn) 397 { 398 return ~ic_expr(tn).bclr; 399 } 400 401 bool 402 attributes_contain(const attribute_list *attrs, const char *str) 403 { 404 for (size_t i = 0, n = attrs->len; i < n; i++) { 405 const attribute *attr = attrs->attrs + i; 406 if (attr->prefix == NULL && strcmp(attr->name, str) == 0) 407 return true; 408 } 409 return false; 410 } 411 412 /* Build 'pointer to tp', 'array of tp' or 'function returning tp'. */ 413 type_t * 414 block_derive_type(type_t *tp, tspec_t t) 415 { 416 417 type_t *tp2 = block_zero_alloc(sizeof(*tp2), "type"); 418 tp2->t_tspec = t; 419 tp2->t_subt = tp; 420 return tp2; 421 } 422 423 /* 424 * Derive 'pointer to tp' or 'function returning tp'. 425 * The memory is freed at the end of the current expression. 426 */ 427 type_t * 428 expr_derive_type(type_t *tp, tspec_t t) 429 { 430 431 type_t *tp2 = expr_zero_alloc(sizeof(*tp2), "type"); 432 tp2->t_tspec = t; 433 tp2->t_subt = tp; 434 return tp2; 435 } 436 437 /* Create an expression from a unary or binary operator and its operands. */ 438 static tnode_t * 439 build_op(op_t op, bool sys, type_t *type, tnode_t *ln, tnode_t *rn) 440 { 441 442 tnode_t *ntn = expr_alloc_tnode(); 443 ntn->tn_op = op; 444 ntn->tn_type = type; 445 ntn->tn_sys = sys; 446 ntn->u.ops.left = ln; 447 ntn->u.ops.right = rn; 448 449 if (op == INDIR || op == FSEL) { 450 lint_assert(ln->tn_type->t_tspec == PTR); 451 tspec_t t = ln->tn_type->t_subt->t_tspec; 452 ntn->tn_lvalue = t != FUNC && t != VOID; 453 } 454 455 return ntn; 456 } 457 458 tnode_t * 459 build_constant(type_t *tp, val_t *v) 460 { 461 462 tnode_t *n = expr_alloc_tnode(); 463 n->tn_op = CON; 464 n->tn_type = tp; 465 n->u.value = *v; 466 n->u.value.v_tspec = tp->t_tspec; 467 free(v); 468 return n; 469 } 470 471 static tnode_t * 472 build_integer_constant(tspec_t t, int64_t si) 473 { 474 475 tnode_t *n = expr_alloc_tnode(); 476 n->tn_op = CON; 477 n->tn_type = gettyp(t); 478 n->u.value.v_tspec = t; 479 n->u.value.v_unsigned_since_c90 = false; 480 n->u.value.v_char_constant = false; 481 n->u.value.u.integer = si; 482 return n; 483 } 484 485 static void 486 fallback_symbol(sym_t *sym) 487 { 488 489 if (Tflag && fallback_symbol_strict_bool(sym)) 490 return; 491 492 if (funcsym != NULL && (strcmp(sym->s_name, "__FUNCTION__") == 0 || 493 strcmp(sym->s_name, "__PRETTY_FUNCTION__") == 0)) { 494 /* __FUNCTION__/__PRETTY_FUNCTION__ is a GCC extension */ 495 gnuism(316); 496 goto return_function_name; 497 } 498 499 if (funcsym != NULL && strcmp(sym->s_name, "__func__") == 0) { 500 if (!allow_c99) 501 /* __func__ is a C99 feature */ 502 warning(317); 503 /* C11 6.4.2.2 */ 504 return_function_name: 505 sym->s_type = block_derive_type(gettyp(CHAR), ARRAY); 506 sym->s_type->t_const = true; 507 sym->s_type->u.dimension = (int)strlen(funcsym->s_name) + 1; 508 return; 509 } 510 511 /* '%s' undefined */ 512 error(99, sym->s_name); 513 } 514 515 /* 516 * Functions that are predeclared by GCC or other compilers can be called 517 * with arbitrary arguments. Since lint usually runs after a successful 518 * compilation, it's the compiler's job to catch any errors. 519 */ 520 bool 521 is_compiler_builtin(const char *name) 522 { 523 /* https://gcc.gnu.org/onlinedocs/gcc/C-Extensions.html */ 524 if (allow_gcc) { 525 if (strncmp(name, "__atomic_", 9) == 0 || 526 strncmp(name, "__builtin_", 10) == 0 || 527 strcmp(name, "alloca") == 0 || 528 /* obsolete but still in use, as of 2021 */ 529 strncmp(name, "__sync_", 7) == 0) 530 return true; 531 } 532 533 /* https://software.intel.com/sites/landingpage/IntrinsicsGuide/ */ 534 if (strncmp(name, "_mm_", 4) == 0) 535 return true; 536 537 return false; 538 } 539 540 /* https://gcc.gnu.org/onlinedocs/gcc/Integer-Overflow-Builtins.html */ 541 static bool 542 is_gcc_bool_builtin(const char *name) 543 { 544 return strncmp(name, "__builtin_", 10) == 0 && 545 (str_ends_with(name, "_overflow") || 546 str_ends_with(name, "_overflow_p")); 547 } 548 549 static void 550 build_name_call(sym_t *sym) 551 { 552 553 if (is_compiler_builtin(sym->s_name)) { 554 /* 555 * Do not warn about these, just assume that they are regular 556 * functions compatible with non-prototype calling conventions. 557 */ 558 if (allow_gcc && is_gcc_bool_builtin(sym->s_name)) 559 sym->s_type = gettyp(BOOL); 560 } else if (allow_c99) 561 /* function '%s' implicitly declared to return int */ 562 error(215, sym->s_name); 563 else if (!allow_trad) 564 /* function '%s' implicitly declared to return int */ 565 warning(215, sym->s_name); 566 567 /* XXX if !allow_c90, the symbol should be exported to level 0 */ 568 sym->s_type = block_derive_type(sym->s_type, FUNC); 569 } 570 571 /* Create a node for a name (symbol table entry). */ 572 tnode_t * 573 build_name(sym_t *sym, bool is_funcname) 574 { 575 576 if (sym->s_scl == NO_SCL && !in_gcc_attribute) { 577 sym->s_scl = EXTERN; 578 sym->s_def = DECL; 579 if (is_funcname) 580 build_name_call(sym); 581 else 582 fallback_symbol(sym); 583 } 584 585 lint_assert(sym->s_kind == SK_VCFT || sym->s_kind == SK_MEMBER); 586 587 tnode_t *n = expr_alloc_tnode(); 588 n->tn_type = sym->s_type; 589 if (sym->s_scl == BOOL_CONST) { 590 n->tn_op = CON; 591 n->u.value.v_tspec = BOOL; 592 n->u.value.v_unsigned_since_c90 = false; 593 n->u.value.v_char_constant = false; 594 n->u.value.u.integer = sym->u.s_bool_constant ? 1 : 0; 595 } else if (sym->s_scl == ENUM_CONST) { 596 n->tn_op = CON; 597 n->u.value.v_tspec = INT; /* ENUM is in n->tn_type */ 598 n->u.value.v_unsigned_since_c90 = false; 599 n->u.value.v_char_constant = false; 600 n->u.value.u.integer = sym->u.s_enum_constant; 601 } else { 602 n->tn_op = NAME; 603 n->u.sym = sym; 604 if (sym->s_kind == SK_VCFT && sym->s_type->t_tspec != FUNC) 605 n->tn_lvalue = true; 606 } 607 608 return n; 609 } 610 611 tnode_t * 612 build_string(buffer *lit) 613 { 614 size_t value_len = lit->len; 615 if (lit->data != NULL) { 616 quoted_iterator it = { .end = 0 }; 617 for (value_len = 0; quoted_next(lit, &it); value_len++) 618 continue; 619 } 620 621 type_t *tp = expr_zero_alloc(sizeof(*tp), "type"); 622 tp->t_tspec = ARRAY; 623 tp->t_subt = gettyp(lit->data != NULL ? CHAR : WCHAR_TSPEC); 624 tp->u.dimension = (int)(value_len + 1); 625 626 tnode_t *n = expr_alloc_tnode(); 627 n->tn_op = STRING; 628 n->tn_type = tp; 629 n->tn_lvalue = true; 630 631 n->u.str_literals = expr_zero_alloc(sizeof(*n->u.str_literals), "tnode.string"); 632 n->u.str_literals->len = lit->len; 633 634 if (lit->data != NULL) { 635 n->u.str_literals->data = expr_zero_alloc(lit->len + 1, 636 "tnode.string.data"); 637 (void)memcpy(n->u.str_literals->data, lit->data, lit->len + 1); 638 free(lit->data); 639 } 640 free(lit); 641 642 return n; 643 } 644 645 tnode_t * 646 build_generic_selection(const tnode_t *expr, 647 struct generic_association *sel) 648 { 649 tnode_t *default_result = NULL; 650 651 for (; sel != NULL; sel = sel->ga_prev) { 652 if (expr != NULL && 653 types_compatible(sel->ga_arg, expr->tn_type, 654 false, false, NULL)) 655 return sel->ga_result; 656 else if (sel->ga_arg == NULL) 657 default_result = sel->ga_result; 658 } 659 return default_result; 660 } 661 662 static bool 663 is_out_of_char_range(const tnode_t *tn) 664 { 665 return tn->tn_op == CON && 666 !tn->u.value.v_char_constant && 667 !(0 <= tn->u.value.u.integer && 668 tn->u.value.u.integer < 1 << (CHAR_SIZE - 1)); 669 } 670 671 static bool 672 check_nonportable_char_comparison(op_t op, 673 const tnode_t *ln, tspec_t lt, 674 const tnode_t *rn, tspec_t rt) 675 { 676 if (!(hflag || pflag)) 677 return true; 678 679 if (lt == CHAR && is_out_of_char_range(rn)) { 680 char buf[128]; 681 (void)snprintf(buf, sizeof(buf), "%s %d", 682 op_name(op), (int)rn->u.value.u.integer); 683 /* nonportable character comparison '%s' */ 684 warning(230, buf); 685 return false; 686 } 687 if (rt == CHAR && is_out_of_char_range(ln)) { 688 char buf[128]; 689 (void)snprintf(buf, sizeof(buf), "%d %s ?", 690 (int)ln->u.value.u.integer, op_name(op)); 691 /* nonportable character comparison '%s' */ 692 warning(230, buf); 693 return false; 694 } 695 return true; 696 } 697 698 static void 699 check_integer_comparison(op_t op, tnode_t *ln, tnode_t *rn) 700 { 701 702 tspec_t lt = ln->tn_type->t_tspec; 703 tspec_t rt = rn->tn_type->t_tspec; 704 705 if (ln->tn_op != CON && rn->tn_op != CON) 706 return; 707 708 if (!is_integer(lt) || !is_integer(rt)) 709 return; 710 711 if (any_query_enabled && !in_system_header) { 712 if (lt == CHAR && rn->tn_op == CON && 713 !rn->u.value.v_char_constant) { 714 /* comparison '%s' of 'char' with plain integer %d */ 715 query_message(14, 716 op_name(op), (int)rn->u.value.u.integer); 717 } 718 if (rt == CHAR && ln->tn_op == CON && 719 !ln->u.value.v_char_constant) { 720 /* comparison '%s' of 'char' with plain integer %d */ 721 query_message(14, 722 op_name(op), (int)ln->u.value.u.integer); 723 } 724 } 725 726 if (!check_nonportable_char_comparison(op, ln, lt, rn, rt)) 727 return; 728 729 if (is_uinteger(lt) && !is_uinteger(rt) && 730 rn->tn_op == CON && rn->u.value.u.integer <= 0) { 731 if (rn->u.value.u.integer < 0) { 732 /* operator '%s' compares '%s' with '%s' */ 733 warning(162, op_name(op), 734 type_name(ln->tn_type), "negative constant"); 735 } else if (op == LT || op == GE) 736 /* operator '%s' compares '%s' with '%s' */ 737 warning(162, op_name(op), type_name(ln->tn_type), "0"); 738 return; 739 } 740 if (is_uinteger(rt) && !is_uinteger(lt) && 741 ln->tn_op == CON && ln->u.value.u.integer <= 0) { 742 if (ln->u.value.u.integer < 0) { 743 /* operator '%s' compares '%s' with '%s' */ 744 warning(162, op_name(op), 745 "negative constant", type_name(rn->tn_type)); 746 } else if (op == GT || op == LE) 747 /* operator '%s' compares '%s' with '%s' */ 748 warning(162, op_name(op), "0", type_name(rn->tn_type)); 749 return; 750 } 751 } 752 753 static const tspec_t arith_rank[] = { 754 LDOUBLE, DOUBLE, FLOAT, 755 #ifdef INT128_SIZE 756 UINT128, INT128, 757 #endif 758 ULLONG, LLONG, 759 ULONG, LONG, 760 UINT, INT, 761 }; 762 763 /* Keep unsigned in traditional C */ 764 static tspec_t 765 usual_arithmetic_conversion_trad(tspec_t lt, tspec_t rt) 766 { 767 768 size_t i; 769 for (i = 0; arith_rank[i] != INT; i++) 770 if (lt == arith_rank[i] || rt == arith_rank[i]) 771 break; 772 773 tspec_t t = arith_rank[i]; 774 if (is_uinteger(lt) || is_uinteger(rt)) 775 if (is_integer(t) && !is_uinteger(t)) 776 return unsigned_type(t); 777 return t; 778 } 779 780 static tspec_t 781 usual_arithmetic_conversion_c90(tspec_t lt, tspec_t rt) 782 { 783 784 if (lt == rt) 785 return lt; 786 787 if (lt == LCOMPLEX || rt == LCOMPLEX) 788 return LCOMPLEX; 789 if (lt == DCOMPLEX || rt == DCOMPLEX) 790 return DCOMPLEX; 791 if (lt == FCOMPLEX || rt == FCOMPLEX) 792 return FCOMPLEX; 793 if (lt == LDOUBLE || rt == LDOUBLE) 794 return LDOUBLE; 795 if (lt == DOUBLE || rt == DOUBLE) 796 return DOUBLE; 797 if (lt == FLOAT || rt == FLOAT) 798 return FLOAT; 799 800 if (size_in_bits(lt) > size_in_bits(rt)) 801 return lt; 802 if (size_in_bits(lt) < size_in_bits(rt)) 803 return rt; 804 805 size_t i; 806 for (i = 3; arith_rank[i] != INT; i++) 807 if (arith_rank[i] == lt || arith_rank[i] == rt) 808 break; 809 if ((is_uinteger(lt) || is_uinteger(rt)) && 810 !is_uinteger(arith_rank[i])) 811 i--; 812 return arith_rank[i]; 813 } 814 815 static tnode_t * 816 apply_usual_arithmetic_conversions(op_t op, tnode_t *tn, tspec_t t) 817 { 818 type_t *ntp = expr_dup_type(tn->tn_type); 819 ntp->t_tspec = t; 820 if (tn->tn_op != CON) { 821 /* usual arithmetic conversion for '%s' from '%s' to '%s' */ 822 query_message(4, op_name(op), 823 type_name(tn->tn_type), type_name(ntp)); 824 } 825 return convert(op, 0, ntp, tn); 826 } 827 828 /* 829 * Apply the "usual arithmetic conversions" (C99 6.3.1.8), which gives both 830 * operands the same type. 831 */ 832 static void 833 balance(op_t op, tnode_t **lnp, tnode_t **rnp) 834 { 835 836 tspec_t lt = (*lnp)->tn_type->t_tspec; 837 tspec_t rt = (*rnp)->tn_type->t_tspec; 838 if (!is_arithmetic(lt) || !is_arithmetic(rt)) 839 return; 840 841 tspec_t t = allow_c90 842 ? usual_arithmetic_conversion_c90(lt, rt) 843 : usual_arithmetic_conversion_trad(lt, rt); 844 845 if (modtab[op].m_comparison 846 && is_integer(lt) && (*lnp)->tn_op != CON 847 && is_floating(t) && (*rnp)->tn_op == CON) 848 /* comparing integer '%s' to floating point constant %Lg */ 849 warning(379, type_name((*lnp)->tn_type), 850 (*rnp)->u.value.u.floating); 851 852 if (t != lt) 853 *lnp = apply_usual_arithmetic_conversions(op, *lnp, t); 854 if (t != rt) 855 *rnp = apply_usual_arithmetic_conversions(op, *rnp, t); 856 857 if (is_integer(t)) { 858 unsigned lw = width_in_bits((*lnp)->tn_type); 859 unsigned rw = width_in_bits((*rnp)->tn_type); 860 if (lw < rw) 861 *lnp = convert(NOOP, 0, (*rnp)->tn_type, *lnp); 862 if (rw < lw) 863 *rnp = convert(NOOP, 0, (*lnp)->tn_type, *rnp); 864 } 865 } 866 867 static tnode_t * 868 build_address(bool sys, tnode_t *tn, bool force) 869 { 870 tspec_t t; 871 872 if (!force && ((t = tn->tn_type->t_tspec) == ARRAY || t == FUNC)) { 873 if (!allow_c90) 874 /* '&' before array or function: ignored */ 875 warning(127); 876 return tn; 877 } 878 879 /* eliminate '&*' */ 880 if (tn->tn_op == INDIR && 881 tn->u.ops.left->tn_type->t_tspec == PTR && 882 tn->u.ops.left->tn_type->t_subt == tn->tn_type) { 883 return tn->u.ops.left; 884 } 885 886 return build_op(ADDR, sys, expr_derive_type(tn->tn_type, PTR), 887 tn, NULL); 888 } 889 890 static uint64_t 891 fold_unsigned_integer(op_t op, uint64_t l, uint64_t r, 892 uint64_t max_value, bool *overflow) 893 { 894 switch (op) { 895 case COMPL: 896 return ~l & max_value; 897 case UPLUS: 898 return +l; 899 case UMINUS: 900 return -l & max_value; 901 case MULT: 902 *overflow = r > 0 && l > max_value / r; 903 return l * r; 904 case DIV: 905 if (r == 0) { 906 /* division by 0 */ 907 error(139); 908 return max_value; 909 } 910 return l / r; 911 case MOD: 912 if (r == 0) { 913 /* modulus by 0 */ 914 error(140); 915 return 0; 916 } 917 return l % r; 918 case PLUS: 919 *overflow = l > max_value - r; 920 return l + r; 921 case MINUS: 922 *overflow = l < r; 923 return l - r; 924 case SHL: 925 /* TODO: warn about out-of-bounds 'r'. */ 926 /* TODO: warn about overflow. */ 927 return l << (r & 63); 928 case SHR: 929 /* TODO: warn about out-of-bounds 'r'. */ 930 return l >> (r & 63); 931 case LT: 932 return l < r ? 1 : 0; 933 case LE: 934 return l <= r ? 1 : 0; 935 case GT: 936 return l > r ? 1 : 0; 937 case GE: 938 return l >= r ? 1 : 0; 939 case EQ: 940 return l == r ? 1 : 0; 941 case NE: 942 return l != r ? 1 : 0; 943 case BITAND: 944 return l & r; 945 case BITXOR: 946 return l ^ r; 947 case BITOR: 948 return l | r; 949 default: 950 lint_assert(/*CONSTCOND*/false); 951 /* NOTREACHED */ 952 } 953 } 954 955 static int64_t 956 fold_signed_integer(op_t op, int64_t l, int64_t r, 957 int64_t min_value, int64_t max_value, bool *overflow) 958 { 959 switch (op) { 960 case COMPL: 961 return ~l; 962 case UPLUS: 963 return +l; 964 case UMINUS: 965 *overflow = l == min_value; 966 return *overflow ? l : -l; 967 case MULT:; 968 uint64_t al = l >= 0 ? (uint64_t)l : -(uint64_t)l; 969 uint64_t ar = r >= 0 ? (uint64_t)r : -(uint64_t)r; 970 bool neg = (l >= 0) != (r >= 0); 971 uint64_t max_prod = (uint64_t)max_value + (neg ? 1 : 0); 972 if (al > 0 && ar > max_prod / al) { 973 *overflow = true; 974 return neg ? min_value : max_value; 975 } 976 return l * r; 977 case DIV: 978 if (r == 0) { 979 /* division by 0 */ 980 error(139); 981 return max_value; 982 } 983 if (l == min_value && r == -1) { 984 *overflow = true; 985 return l; 986 } 987 return l / r; 988 case MOD: 989 if (r == 0) { 990 /* modulus by 0 */ 991 error(140); 992 return 0; 993 } 994 if (l == min_value && r == -1) { 995 *overflow = true; 996 return 0; 997 } 998 return l % r; 999 case PLUS: 1000 if (r > 0 && l > max_value - r) { 1001 *overflow = true; 1002 return max_value; 1003 } 1004 if (r < 0 && l < min_value - r) { 1005 *overflow = true; 1006 return min_value; 1007 } 1008 return l + r; 1009 case MINUS: 1010 if (r > 0 && l < min_value + r) { 1011 *overflow = true; 1012 return min_value; 1013 } 1014 if (r < 0 && l > max_value + r) { 1015 *overflow = true; 1016 return max_value; 1017 } 1018 return l - r; 1019 case SHL: 1020 /* TODO: warn about out-of-bounds 'r'. */ 1021 /* TODO: warn about overflow. */ 1022 return l << (r & 63); 1023 case SHR: 1024 /* TODO: warn about out-of-bounds 'r'. */ 1025 if (l < 0) 1026 return (int64_t)~(~(uint64_t)l >> (r & 63)); 1027 return (int64_t)((uint64_t)l >> (r & 63)); 1028 case LT: 1029 return l < r ? 1 : 0; 1030 case LE: 1031 return l <= r ? 1 : 0; 1032 case GT: 1033 return l > r ? 1 : 0; 1034 case GE: 1035 return l >= r ? 1 : 0; 1036 case EQ: 1037 return l == r ? 1 : 0; 1038 case NE: 1039 return l != r ? 1 : 0; 1040 case BITAND: 1041 return l & r; 1042 case BITXOR: 1043 return l ^ r; 1044 case BITOR: 1045 return l | r; 1046 default: 1047 lint_assert(/*CONSTCOND*/false); 1048 /* NOTREACHED */ 1049 } 1050 } 1051 1052 static tnode_t * 1053 fold_constant_integer(tnode_t *tn) 1054 { 1055 1056 lint_assert(has_operands(tn)); 1057 tspec_t t = tn->u.ops.left->tn_type->t_tspec; 1058 int64_t l = tn->u.ops.left->u.value.u.integer; 1059 int64_t r = is_binary(tn) ? tn->u.ops.right->u.value.u.integer : 0; 1060 uint64_t mask = value_bits(size_in_bits(t)); 1061 1062 int64_t res; 1063 bool overflow = false; 1064 if (!is_integer(t) || is_uinteger(t)) { 1065 uint64_t u_res = fold_unsigned_integer(tn->tn_op, 1066 (uint64_t)l, (uint64_t)r, mask, &overflow); 1067 if (u_res > mask) 1068 overflow = true; 1069 res = (int64_t)u_res; 1070 if (overflow && hflag) { 1071 char buf[128]; 1072 if (is_binary(tn)) { 1073 snprintf(buf, sizeof(buf), "%ju %s %ju", 1074 (uintmax_t)l, op_name(tn->tn_op), 1075 (uintmax_t)r); 1076 } else { 1077 snprintf(buf, sizeof(buf), "%s%ju", 1078 op_name(tn->tn_op), (uintmax_t)l); 1079 } 1080 /* '%s' overflows '%s' */ 1081 warning(141, buf, type_name(tn->tn_type)); 1082 } 1083 } else { 1084 int64_t max_value = (int64_t)(mask >> 1); 1085 int64_t min_value = -max_value - 1; 1086 res = fold_signed_integer(tn->tn_op, 1087 l, r, min_value, max_value, &overflow); 1088 if (res < min_value || res > max_value) 1089 overflow = true; 1090 if (overflow && hflag) { 1091 char buf[128]; 1092 if (is_binary(tn)) { 1093 snprintf(buf, sizeof(buf), "%jd %s %jd", 1094 (intmax_t)l, op_name(tn->tn_op), 1095 (intmax_t)r); 1096 } else if (tn->tn_op == UMINUS && l < 0) { 1097 snprintf(buf, sizeof(buf), "-(%jd)", 1098 (intmax_t)l); 1099 } else { 1100 snprintf(buf, sizeof(buf), "%s%jd", 1101 op_name(tn->tn_op), (intmax_t)l); 1102 } 1103 /* '%s' overflows '%s' */ 1104 warning(141, buf, type_name(tn->tn_type)); 1105 } 1106 } 1107 1108 val_t *v = xcalloc(1, sizeof(*v)); 1109 v->v_tspec = tn->tn_type->t_tspec; 1110 v->u.integer = convert_integer(res, t, size_in_bits(t)); 1111 1112 tnode_t *cn = build_constant(tn->tn_type, v); 1113 if (tn->u.ops.left->tn_system_dependent) 1114 cn->tn_system_dependent = true; 1115 if (is_binary(tn) && tn->u.ops.right->tn_system_dependent) 1116 cn->tn_system_dependent = true; 1117 1118 return cn; 1119 } 1120 1121 static tnode_t * 1122 build_struct_access(op_t op, bool sys, tnode_t *ln, tnode_t *rn) 1123 { 1124 1125 lint_assert(rn->tn_op == NAME); 1126 lint_assert(is_member(rn->u.sym)); 1127 1128 bool lvalue = op == ARROW || ln->tn_lvalue; 1129 1130 if (op == POINT) 1131 ln = build_address(sys, ln, true); 1132 else if (ln->tn_type->t_tspec != PTR) { 1133 lint_assert(!allow_c90); 1134 lint_assert(is_integer(ln->tn_type->t_tspec)); 1135 ln = convert(NOOP, 0, expr_derive_type(gettyp(VOID), PTR), ln); 1136 } 1137 1138 tnode_t *ctn = build_integer_constant(PTRDIFF_TSPEC, 1139 rn->u.sym->u.s_member.sm_offset_in_bits / CHAR_SIZE); 1140 1141 type_t *ptr_tp = expr_derive_type(rn->tn_type, PTR); 1142 tnode_t *ntn = build_op(PLUS, sys, ptr_tp, ln, ctn); 1143 if (ln->tn_op == CON) 1144 ntn = fold_constant_integer(ntn); 1145 1146 op_t nop = rn->tn_type->t_bitfield ? FSEL : INDIR; 1147 ntn = build_op(nop, sys, ntn->tn_type->t_subt, ntn, NULL); 1148 if (!lvalue) 1149 ntn->tn_lvalue = false; 1150 1151 return ntn; 1152 } 1153 1154 /* 1155 * Get the size in bytes of type tp->t_subt, as a constant expression of type 1156 * ptrdiff_t as seen from the target platform. 1157 */ 1158 static tnode_t * 1159 subt_size_in_bytes(type_t *tp) 1160 { 1161 1162 lint_assert(tp->t_tspec == PTR); 1163 tp = tp->t_subt; 1164 1165 int elem = 1; 1166 while (tp->t_tspec == ARRAY) { 1167 elem *= tp->u.dimension; 1168 tp = tp->t_subt; 1169 } 1170 1171 int elsz_in_bits = 0; 1172 switch (tp->t_tspec) { 1173 case FUNC: 1174 /* pointer to function is not allowed here */ 1175 error(110); 1176 break; 1177 case VOID: 1178 /* cannot do pointer arithmetic on operand of unknown size */ 1179 gnuism(136); 1180 break; 1181 case STRUCT: 1182 case UNION: 1183 if ((elsz_in_bits = (int)tp->u.sou->sou_size_in_bits) == 0) 1184 /* cannot do pointer arithmetic on operand of ... */ 1185 error(136); 1186 break; 1187 case ENUM: 1188 if (is_incomplete(tp)) 1189 /* cannot do pointer arithmetic on operand of ... */ 1190 warning(136); 1191 /* FALLTHROUGH */ 1192 default: 1193 if ((elsz_in_bits = size_in_bits(tp->t_tspec)) == 0) 1194 /* cannot do pointer arithmetic on operand of ... */ 1195 error(136); 1196 else 1197 lint_assert(elsz_in_bits != -1); 1198 break; 1199 } 1200 1201 if (elem == 0 && elsz_in_bits != 0) 1202 /* cannot do pointer arithmetic on operand of unknown size */ 1203 error(136); 1204 1205 if (elsz_in_bits == 0) 1206 elsz_in_bits = CHAR_SIZE; 1207 1208 return build_integer_constant(PTRDIFF_TSPEC, 1209 (int64_t)(elem * elsz_in_bits / CHAR_SIZE)); 1210 } 1211 1212 static tnode_t * 1213 build_prepost_incdec(op_t op, bool sys, tnode_t *ln) 1214 { 1215 1216 lint_assert(ln != NULL); 1217 tnode_t *cn = ln->tn_type->t_tspec == PTR 1218 ? subt_size_in_bytes(ln->tn_type) 1219 : build_integer_constant(INT, 1); 1220 return build_op(op, sys, ln->tn_type, ln, cn); 1221 } 1222 1223 static void 1224 check_enum_array_index(const tnode_t *ln, const tnode_t *rn) 1225 { 1226 1227 if (ln->tn_op != ADDR || ln->u.ops.left->tn_op != NAME) 1228 return; 1229 1230 const type_t *ltp = ln->u.ops.left->tn_type; 1231 if (ltp->t_tspec != ARRAY || ltp->t_incomplete_array) 1232 return; 1233 1234 if (rn->tn_op != CVT || !rn->tn_type->t_is_enum) 1235 return; 1236 if (rn->u.ops.left->tn_op != LOAD) 1237 return; 1238 1239 const type_t *rtp = rn->u.ops.left->tn_type; 1240 const sym_t *ec = rtp->u.enumer->en_first_enumerator; 1241 const sym_t *max_ec = ec; 1242 lint_assert(ec != NULL); 1243 for (ec = ec->s_next; ec != NULL; ec = ec->s_next) 1244 if (ec->u.s_enum_constant > max_ec->u.s_enum_constant) 1245 max_ec = ec; 1246 1247 int64_t max_enum_value = max_ec->u.s_enum_constant; 1248 lint_assert(INT_MIN <= max_enum_value && max_enum_value <= INT_MAX); 1249 1250 int max_array_index = ltp->u.dimension - 1; 1251 if (max_enum_value == max_array_index) 1252 return; 1253 1254 if (max_enum_value == max_array_index + 1 && 1255 (strstr(max_ec->s_name, "MAX") != NULL || 1256 strstr(max_ec->s_name, "max") != NULL || 1257 strstr(max_ec->s_name, "NUM") != NULL || 1258 strstr(max_ec->s_name, "num") != NULL || 1259 strncmp(max_ec->s_name, "N_", 2) == 0)) 1260 return; 1261 1262 /* maximum value %d for '%s' of type '%s' does not match maximum array index %d */ 1263 warning(348, (int)max_enum_value, max_ec->s_name, type_name(rtp), 1264 max_array_index); 1265 print_previous_declaration(max_ec); 1266 } 1267 1268 static tnode_t * 1269 build_plus_minus(op_t op, bool sys, tnode_t *ln, tnode_t *rn) 1270 { 1271 1272 if (rn->tn_type->t_tspec == PTR && is_integer(ln->tn_type->t_tspec)) { 1273 tnode_t *tmp = ln; 1274 ln = rn; 1275 rn = tmp; 1276 /* pointer addition has integer on the left-hand side */ 1277 query_message(5); 1278 } 1279 1280 /* pointer +- integer */ 1281 tspec_t lt = ln->tn_type->t_tspec; 1282 tspec_t rt = rn->tn_type->t_tspec; 1283 if (lt == PTR && rt != PTR) { 1284 lint_assert(is_integer(rt)); 1285 1286 check_ctype_macro_invocation(ln, rn); 1287 check_enum_array_index(ln, rn); 1288 1289 tnode_t *elsz = subt_size_in_bytes(ln->tn_type); 1290 tspec_t szt = elsz->tn_type->t_tspec; 1291 if (rt != szt && rt != unsigned_type(szt)) 1292 rn = convert(NOOP, 0, elsz->tn_type, rn); 1293 1294 tnode_t *prod = build_op(MULT, sys, rn->tn_type, rn, elsz); 1295 if (rn->tn_op == CON) 1296 prod = fold_constant_integer(prod); 1297 1298 return build_op(op, sys, ln->tn_type, ln, prod); 1299 } 1300 1301 /* pointer - pointer */ 1302 if (rt == PTR) { 1303 lint_assert(lt == PTR); 1304 lint_assert(op == MINUS); 1305 1306 type_t *ptrdiff = gettyp(PTRDIFF_TSPEC); 1307 tnode_t *raw_diff = build_op(op, sys, ptrdiff, ln, rn); 1308 if (ln->tn_op == CON && rn->tn_op == CON) 1309 raw_diff = fold_constant_integer(raw_diff); 1310 1311 tnode_t *elsz = subt_size_in_bytes(ln->tn_type); 1312 balance(NOOP, &raw_diff, &elsz); 1313 1314 return build_op(DIV, sys, ptrdiff, raw_diff, elsz); 1315 } 1316 1317 return build_op(op, sys, ln->tn_type, ln, rn); 1318 } 1319 1320 static tnode_t * 1321 build_bit_shift(op_t op, bool sys, tnode_t *ln, tnode_t *rn) 1322 { 1323 1324 if (!allow_c90 && rn->tn_type->t_tspec != INT) 1325 // XXX: C1978 7.5 says: "Both [operators] perform the usual 1326 // arithmetic conversions on their operands." 1327 // TODO: Add a test to exercise this part of the code. 1328 rn = convert(NOOP, 0, gettyp(INT), rn); 1329 return build_op(op, sys, ln->tn_type, ln, rn); 1330 } 1331 1332 static bool 1333 is_null_pointer(const tnode_t *tn) 1334 { 1335 tspec_t t = tn->tn_type->t_tspec; 1336 1337 // TODO: Investigate how other pointers are stored, in particular, 1338 // whether a pointer constant can have a non-zero value. 1339 // If not, simplify the code below. 1340 return ((t == PTR && tn->tn_type->t_subt->t_tspec == VOID) 1341 || is_integer(t)) 1342 && (tn->tn_op == CON && tn->u.value.u.integer == 0); 1343 } 1344 1345 /* Return a type based on tp1, with added qualifiers from tp2. */ 1346 static type_t * 1347 merge_qualifiers(type_t *tp1, const type_t *tp2) 1348 { 1349 1350 lint_assert(tp1->t_tspec == PTR); 1351 lint_assert(tp2->t_tspec == PTR); 1352 1353 bool c1 = tp1->t_subt->t_const; 1354 bool c2 = tp2->t_subt->t_const; 1355 bool v1 = tp1->t_subt->t_volatile; 1356 bool v2 = tp2->t_subt->t_volatile; 1357 1358 if (c1 == (c1 | c2) && v1 == (v1 | v2)) 1359 return tp1; 1360 1361 type_t *nstp = expr_dup_type(tp1->t_subt); 1362 nstp->t_const |= c2; 1363 nstp->t_volatile |= v2; 1364 1365 type_t *ntp = expr_dup_type(tp1); 1366 ntp->t_subt = nstp; 1367 return ntp; 1368 } 1369 1370 /* See C99 6.5.15 "Conditional operator". */ 1371 static tnode_t * 1372 build_colon(bool sys, tnode_t *ln, tnode_t *rn) 1373 { 1374 tspec_t lt = ln->tn_type->t_tspec; 1375 tspec_t rt = rn->tn_type->t_tspec; 1376 1377 type_t *tp; 1378 if (is_arithmetic(lt) && is_arithmetic(rt)) 1379 /* The operands were already balanced in build_binary. */ 1380 tp = ln->tn_type; 1381 else if (lt == BOOL && rt == BOOL) 1382 tp = ln->tn_type; 1383 else if (lt == VOID || rt == VOID) 1384 tp = gettyp(VOID); 1385 else if (is_struct_or_union(lt)) { 1386 lint_assert(is_struct_or_union(rt)); 1387 lint_assert(ln->tn_type->u.sou == rn->tn_type->u.sou); 1388 if (is_incomplete(ln->tn_type)) { 1389 /* unknown operand size, op '%s' */ 1390 error(138, op_name(COLON)); 1391 return NULL; 1392 } 1393 tp = ln->tn_type; 1394 } else if (lt == PTR && is_integer(rt)) { 1395 if (rt != PTRDIFF_TSPEC) 1396 rn = convert(NOOP, 0, gettyp(PTRDIFF_TSPEC), rn); 1397 tp = ln->tn_type; 1398 } else if (rt == PTR && is_integer(lt)) { 1399 if (lt != PTRDIFF_TSPEC) 1400 ln = convert(NOOP, 0, gettyp(PTRDIFF_TSPEC), ln); 1401 tp = rn->tn_type; 1402 } else if (lt == PTR && is_null_pointer(rn)) 1403 tp = merge_qualifiers(ln->tn_type, rn->tn_type); 1404 else if (rt == PTR && is_null_pointer(ln)) 1405 tp = merge_qualifiers(rn->tn_type, ln->tn_type); 1406 else if (lt == PTR && ln->tn_type->t_subt->t_tspec == VOID) 1407 tp = merge_qualifiers(ln->tn_type, rn->tn_type); 1408 else if (rt == PTR && rn->tn_type->t_subt->t_tspec == VOID) 1409 tp = merge_qualifiers(rn->tn_type, ln->tn_type); 1410 else { 1411 /* 1412 * XXX For now we simply take the left type. This is probably 1413 * wrong, if one type contains a function prototype and the 1414 * other one, at the same place, only an old-style declaration. 1415 */ 1416 tp = merge_qualifiers(ln->tn_type, rn->tn_type); 1417 } 1418 1419 return build_op(COLON, sys, tp, ln, rn); 1420 } 1421 1422 /* TODO: check for varargs */ 1423 static bool 1424 is_cast_redundant(const tnode_t *tn) 1425 { 1426 const type_t *ntp = tn->tn_type, *otp = tn->u.ops.left->tn_type; 1427 tspec_t nt = ntp->t_tspec, ot = otp->t_tspec; 1428 1429 if (nt == BOOL || ot == BOOL) 1430 return nt == BOOL && ot == BOOL; 1431 1432 if (is_integer(nt) && is_integer(ot)) { 1433 unsigned int nw = width_in_bits(ntp), ow = width_in_bits(otp); 1434 if (is_uinteger(nt) == is_uinteger(ot)) 1435 return nw >= ow; 1436 return is_uinteger(ot) && nw > ow; 1437 } 1438 1439 if (is_complex(nt) || is_complex(ot)) 1440 return is_complex(nt) && is_complex(ot) && 1441 size_in_bits(nt) >= size_in_bits(ot); 1442 1443 if (is_floating(nt) && is_floating(ot)) 1444 return size_in_bits(nt) >= size_in_bits(ot); 1445 1446 if (nt == PTR && ot == PTR) { 1447 if (!ntp->t_subt->t_const && otp->t_subt->t_const) 1448 return false; 1449 if (!ntp->t_subt->t_volatile && otp->t_subt->t_volatile) 1450 return false; 1451 1452 if (ntp->t_subt->t_tspec == VOID || 1453 otp->t_subt->t_tspec == VOID || 1454 types_compatible(ntp->t_subt, otp->t_subt, 1455 false, false, NULL)) 1456 return true; 1457 } 1458 1459 return false; 1460 } 1461 1462 static bool 1463 is_assignment(op_t op) 1464 { 1465 1466 return op == ASSIGN || 1467 op == MULASS || 1468 op == DIVASS || 1469 op == MODASS || 1470 op == ADDASS || 1471 op == SUBASS || 1472 op == SHLASS || 1473 op == SHRASS || 1474 op == ANDASS || 1475 op == XORASS || 1476 op == ORASS || 1477 op == RETURN || 1478 op == INIT; 1479 } 1480 1481 static tnode_t * 1482 build_assignment(op_t op, bool sys, tnode_t *ln, tnode_t *rn) 1483 { 1484 1485 tspec_t lt = ln->tn_type->t_tspec; 1486 tspec_t rt = rn->tn_type->t_tspec; 1487 1488 if (is_assignment(rn->tn_op)) 1489 /* chained assignment with '%s' and '%s' */ 1490 query_message(10, op_name(op), op_name(rn->tn_op)); 1491 1492 if ((op == ADDASS || op == SUBASS) && lt == PTR) { 1493 lint_assert(is_integer(rt)); 1494 tnode_t *ctn = subt_size_in_bytes(ln->tn_type); 1495 if (rn->tn_type->t_tspec != ctn->tn_type->t_tspec) 1496 rn = convert(NOOP, 0, ctn->tn_type, rn); 1497 rn = build_op(MULT, sys, rn->tn_type, rn, ctn); 1498 if (rn->u.ops.left->tn_op == CON) 1499 rn = fold_constant_integer(rn); 1500 } 1501 1502 if ((op == ASSIGN || op == RETURN || op == INIT) && 1503 (lt == STRUCT || rt == STRUCT)) { 1504 lint_assert(lt == rt); 1505 lint_assert(ln->tn_type->u.sou == rn->tn_type->u.sou); 1506 if (is_incomplete(ln->tn_type)) { 1507 if (op == RETURN) 1508 /* cannot return incomplete type */ 1509 error(212); 1510 else 1511 /* unknown operand size, op '%s' */ 1512 error(138, op_name(op)); 1513 return NULL; 1514 } 1515 } 1516 1517 if (op == SHLASS && hflag && allow_trad && allow_c90 1518 && portable_rank_cmp(lt, rt) < 0) 1519 /* semantics of '%s' change in C90; ... */ 1520 warning(118, "<<="); 1521 1522 if (op != SHLASS && op != SHRASS 1523 && (op == ASSIGN || lt != PTR) 1524 && (lt != rt || (ln->tn_type->t_bitfield && rn->tn_op == CON))) { 1525 rn = convert(op, 0, ln->tn_type, rn); 1526 rt = lt; 1527 } 1528 1529 if (lt == PTR && ln->tn_type->t_subt->t_tspec != VOID 1530 && rt == PTR && rn->tn_type->t_subt->t_tspec == VOID 1531 && !is_null_pointer(rn)) 1532 /* implicit narrowing conversion from void ... */ 1533 query_message(20, type_name(ln->tn_type)); 1534 1535 if (any_query_enabled && rn->tn_op == CVT && rn->tn_cast && 1536 types_compatible(ln->tn_type, rn->tn_type, false, false, NULL) && 1537 is_cast_redundant(rn)) { 1538 /* redundant cast from '%s' to '%s' before assignment */ 1539 query_message(7, type_name(rn->u.ops.left->tn_type), 1540 type_name(rn->tn_type)); 1541 } 1542 1543 return build_op(op, sys, ln->tn_type, ln, rn); 1544 } 1545 1546 static tnode_t * 1547 build_real_imag(op_t op, bool sys, tnode_t *ln) 1548 { 1549 1550 lint_assert(ln != NULL); 1551 if (ln->tn_op == NAME) { 1552 /* 1553 * This may be too much, but it avoids wrong warnings. See 1554 * d_c99_complex_split.c. 1555 */ 1556 mark_as_used(ln->u.sym, false, false); 1557 mark_as_set(ln->u.sym); 1558 } 1559 1560 tspec_t t; 1561 switch (ln->tn_type->t_tspec) { 1562 case LCOMPLEX: 1563 t = LDOUBLE; 1564 break; 1565 case DCOMPLEX: 1566 t = DOUBLE; 1567 break; 1568 case FCOMPLEX: 1569 t = FLOAT; 1570 break; 1571 default: 1572 /* '__%s__' is illegal for type '%s' */ 1573 error(276, op == REAL ? "real" : "imag", 1574 type_name(ln->tn_type)); 1575 return NULL; 1576 } 1577 1578 tnode_t *ntn = build_op(op, sys, gettyp(t), ln, NULL); 1579 ntn->tn_lvalue = true; 1580 return ntn; 1581 } 1582 1583 static bool 1584 is_confusing_precedence(op_t op, const tnode_t *operand, op_t *cop) 1585 { 1586 if (operand->tn_parenthesized) 1587 return false; 1588 op_t oop = operand->tn_op; 1589 1590 if (op == SHL || op == SHR) { 1591 if (oop == PLUS || oop == MINUS) 1592 return *cop = oop, true; 1593 return false; 1594 } 1595 1596 if (op == LOGOR) { 1597 if (oop == LOGAND) 1598 return *cop = oop, true; 1599 return false; 1600 } 1601 1602 lint_assert(op == BITAND || op == BITXOR || op == BITOR); 1603 if (oop != op 1604 && (oop == PLUS || oop == MINUS || oop == BITAND || oop == BITXOR)) 1605 return *cop = oop, true; 1606 return false; 1607 } 1608 1609 /* 1610 * Print a warning if the given node has operands which should be 1611 * parenthesized. 1612 * 1613 * XXX Does not work if an operand is a constant expression. Constant 1614 * expressions are already folded. 1615 */ 1616 static void 1617 check_precedence_confusion(tnode_t *tn) 1618 { 1619 tnode_t *ln, *rn; 1620 1621 if (!hflag) 1622 return; 1623 1624 debug_node(tn); 1625 1626 lint_assert(is_binary(tn)); 1627 for (ln = tn->u.ops.left; ln->tn_op == CVT; ln = ln->u.ops.left) 1628 continue; 1629 for (rn = tn->u.ops.right; rn->tn_op == CVT; rn = rn->u.ops.left) 1630 continue; 1631 1632 op_t cop; 1633 if (is_confusing_precedence(tn->tn_op, ln, &cop) || 1634 is_confusing_precedence(tn->tn_op, rn, &cop)) { 1635 /* possible precedence confusion between '%s' and '%s' */ 1636 warning(169, op_name(tn->tn_op), op_name(cop)); 1637 } 1638 } 1639 1640 static tnode_t * 1641 fold_constant_compare_zero(tnode_t *tn) 1642 { 1643 1644 val_t *v = xcalloc(1, sizeof(*v)); 1645 v->v_tspec = tn->tn_type->t_tspec; 1646 lint_assert(v->v_tspec == INT || (Tflag && v->v_tspec == BOOL)); 1647 1648 lint_assert(has_operands(tn)); 1649 bool l = constant_is_nonzero(tn->u.ops.left); 1650 bool r = is_binary(tn) && constant_is_nonzero(tn->u.ops.right); 1651 1652 switch (tn->tn_op) { 1653 case NOT: 1654 if (hflag && !suppress_constcond) 1655 /* constant operand to '!' */ 1656 warning(239); 1657 v->u.integer = !l ? 1 : 0; 1658 break; 1659 case LOGAND: 1660 v->u.integer = l && r ? 1 : 0; 1661 break; 1662 case LOGOR: 1663 v->u.integer = l || r ? 1 : 0; 1664 break; 1665 default: 1666 lint_assert(/*CONSTCOND*/false); 1667 } 1668 1669 return build_constant(tn->tn_type, v); 1670 } 1671 1672 static long double 1673 floating_error_value(tspec_t t, long double lv) 1674 { 1675 if (t == FLOAT) 1676 return lv < 0 ? -FLT_MAX : FLT_MAX; 1677 if (t == DOUBLE) 1678 return lv < 0 ? -DBL_MAX : DBL_MAX; 1679 /* 1680 * When NetBSD is cross-built in MKLINT=yes mode on x86_64 for sparc64, 1681 * tools/lint checks this code while building usr.bin/xlint. In that 1682 * situation, lint uses the preprocessor for sparc64, in which the type 1683 * 'long double' is IEEE-754-binary128, affecting the macro LDBL_MAX 1684 * below. The type 'long double', as well as the strtold 1685 * implementation, comes from the host platform x86_64 though, where 1686 * 'long double' consumes 128 bits as well but only uses 80 of them. 1687 * The exponent range of the two 'long double' types is the same, but 1688 * the maximum finite value differs due to the extended precision on 1689 * sparc64. 1690 * 1691 * To properly handle the data types of the target platform, lint would 1692 * have to implement the floating-point types in a platform-independent 1693 * way, which is not worth the effort, given how few programs 1694 * practically use 'long double'. 1695 */ 1696 /* LINTED 248: floating-point constant out of range */ 1697 long double max = LDBL_MAX; 1698 return lv < 0 ? -max : max; 1699 } 1700 1701 static bool 1702 is_floating_overflow(tspec_t t, long double val) 1703 { 1704 if (fpe != 0 || isfinite(val) == 0) 1705 return true; 1706 if (t == FLOAT && (val > FLT_MAX || val < -FLT_MAX)) 1707 return true; 1708 if (t == DOUBLE && (val > DBL_MAX || val < -DBL_MAX)) 1709 return true; 1710 return false; 1711 } 1712 1713 static tnode_t * 1714 fold_constant_floating(tnode_t *tn) 1715 { 1716 1717 fpe = 0; 1718 1719 tspec_t t = tn->tn_type->t_tspec; 1720 1721 val_t *v = xcalloc(1, sizeof(*v)); 1722 v->v_tspec = t; 1723 1724 lint_assert(is_floating(t)); 1725 lint_assert(has_operands(tn)); 1726 lint_assert(t == tn->u.ops.left->tn_type->t_tspec); 1727 lint_assert(!is_binary(tn) || t == tn->u.ops.right->tn_type->t_tspec); 1728 1729 long double lv = tn->u.ops.left->u.value.u.floating; 1730 long double rv = is_binary(tn) ? tn->u.ops.right->u.value.u.floating 1731 : 0.0; 1732 1733 switch (tn->tn_op) { 1734 case UPLUS: 1735 v->u.floating = lv; 1736 break; 1737 case UMINUS: 1738 v->u.floating = -lv; 1739 break; 1740 case MULT: 1741 v->u.floating = lv * rv; 1742 break; 1743 case DIV: 1744 if (rv == 0.0) { 1745 /* division by 0 */ 1746 error(139); 1747 v->u.floating = floating_error_value(t, lv); 1748 } else { 1749 v->u.floating = lv / rv; 1750 } 1751 break; 1752 case PLUS: 1753 v->u.floating = lv + rv; 1754 break; 1755 case MINUS: 1756 v->u.floating = lv - rv; 1757 break; 1758 case LT: 1759 v->u.integer = lv < rv ? 1 : 0; 1760 break; 1761 case LE: 1762 v->u.integer = lv <= rv ? 1 : 0; 1763 break; 1764 case GE: 1765 v->u.integer = lv >= rv ? 1 : 0; 1766 break; 1767 case GT: 1768 v->u.integer = lv > rv ? 1 : 0; 1769 break; 1770 case EQ: 1771 v->u.integer = lv == rv ? 1 : 0; 1772 break; 1773 case NE: 1774 v->u.integer = lv != rv ? 1 : 0; 1775 break; 1776 default: 1777 lint_assert(/*CONSTCOND*/false); 1778 } 1779 1780 // XXX: Must not access u.floating after setting u.integer. 1781 lint_assert(fpe != 0 || isnan(v->u.floating) == 0); 1782 if (is_complex(v->v_tspec)) { 1783 /* 1784 * Don't warn, as lint doesn't model the imaginary part of 1785 * complex numbers. 1786 */ 1787 fpe = 0; 1788 } else if (is_floating_overflow(t, v->u.floating)) { 1789 /* operator '%s' produces floating point overflow */ 1790 warning(142, op_name(tn->tn_op)); 1791 v->u.floating = floating_error_value(t, v->u.floating); 1792 fpe = 0; 1793 } 1794 1795 return build_constant(tn->tn_type, v); 1796 } 1797 1798 static void 1799 use(const tnode_t *tn) 1800 { 1801 if (tn == NULL) 1802 return; 1803 switch (tn->tn_op) { 1804 case NAME: 1805 mark_as_used(tn->u.sym, false /* XXX */, false /* XXX */); 1806 break; 1807 case CON: 1808 case STRING: 1809 break; 1810 case CALL:; 1811 const function_call *call = tn->u.call; 1812 for (size_t i = 0, n = call->args_len; i < n; i++) 1813 use(call->args[i]); 1814 break; 1815 default: 1816 lint_assert(has_operands(tn)); 1817 use(tn->u.ops.left); 1818 if (is_binary(tn)) 1819 use(tn->u.ops.right); 1820 } 1821 } 1822 1823 /* 1824 * Create a tree node for a binary operator and its two operands. Also called 1825 * for unary operators; in that case rn is NULL. 1826 * 1827 * Function calls, sizeof and casts are handled elsewhere. 1828 */ 1829 tnode_t * 1830 build_binary(tnode_t *ln, op_t op, bool sys, tnode_t *rn) 1831 { 1832 const mod_t *mp = &modtab[op]; 1833 1834 /* If there was an error in one of the operands, return. */ 1835 if (ln == NULL || (mp->m_binary && rn == NULL)) 1836 return NULL; 1837 1838 if (mp->m_value_context || mp->m_compares_with_zero) 1839 ln = cconv(ln); 1840 if (mp->m_binary && op != ARROW && op != POINT) 1841 rn = cconv(rn); 1842 1843 if (mp->m_comparison) 1844 check_integer_comparison(op, ln, rn); 1845 1846 if (mp->m_value_context || mp->m_compares_with_zero) 1847 ln = promote(op, false, ln); 1848 if (mp->m_binary && op != ARROW && op != POINT && 1849 op != ASSIGN && op != RETURN && op != INIT) 1850 rn = promote(op, false, rn); 1851 1852 if (mp->m_warn_if_left_unsigned_in_c90 && 1853 ln->tn_op == CON && ln->u.value.v_unsigned_since_c90) { 1854 /* C90 treats constant as unsigned, op '%s' */ 1855 warning(218, op_name(op)); 1856 ln->u.value.v_unsigned_since_c90 = false; 1857 } 1858 if (mp->m_warn_if_right_unsigned_in_c90 && 1859 rn->tn_op == CON && rn->u.value.v_unsigned_since_c90) { 1860 /* C90 treats constant as unsigned, op '%s' */ 1861 warning(218, op_name(op)); 1862 rn->u.value.v_unsigned_since_c90 = false; 1863 } 1864 1865 if (mp->m_balance_operands || (!allow_c90 && (op == SHL || op == SHR))) 1866 balance(op, &ln, &rn); 1867 1868 if (!typeok(op, 0, ln, rn)) 1869 return NULL; 1870 1871 tnode_t *ntn; 1872 switch (op) { 1873 case POINT: 1874 case ARROW: 1875 ntn = build_struct_access(op, sys, ln, rn); 1876 break; 1877 case NOT: 1878 if (ln->tn_op == ASSIGN && ln->u.ops.right->tn_op == CON) { 1879 /* constant assignment of type '%s' in operand ... */ 1880 warning(382, type_name(ln->tn_type), 1881 is_nonzero_val(&ln->u.ops.right->u.value) 1882 ? "true" : "false"); 1883 } 1884 ntn = build_op(op, sys, gettyp(Tflag ? BOOL : INT), ln, NULL); 1885 break; 1886 case INCAFT: 1887 case DECAFT: 1888 case INCBEF: 1889 case DECBEF: 1890 ntn = build_prepost_incdec(op, sys, ln); 1891 break; 1892 case ADDR: 1893 ntn = build_address(sys, ln, false); 1894 break; 1895 case INDIR: 1896 ntn = build_op(INDIR, sys, ln->tn_type->t_subt, ln, NULL); 1897 break; 1898 case PLUS: 1899 case MINUS: 1900 ntn = build_plus_minus(op, sys, ln, rn); 1901 break; 1902 case SHL: 1903 case SHR: 1904 ntn = build_bit_shift(op, sys, ln, rn); 1905 break; 1906 case COLON: 1907 ntn = build_colon(sys, ln, rn); 1908 break; 1909 case ASSIGN: 1910 case MULASS: 1911 case DIVASS: 1912 case MODASS: 1913 case ADDASS: 1914 case SUBASS: 1915 case SHLASS: 1916 case SHRASS: 1917 case ANDASS: 1918 case XORASS: 1919 case ORASS: 1920 case RETURN: 1921 case INIT: 1922 ntn = build_assignment(op, sys, ln, rn); 1923 break; 1924 case COMMA: 1925 /* comma operator with types '%s' and '%s' */ 1926 query_message(12, 1927 type_name(ln->tn_type), type_name(rn->tn_type)); 1928 /* FALLTHROUGH */ 1929 case QUEST: 1930 ntn = build_op(op, sys, rn->tn_type, ln, rn); 1931 break; 1932 case REAL: 1933 case IMAG: 1934 ntn = build_real_imag(op, sys, ln); 1935 break; 1936 default: 1937 lint_assert(mp->m_binary == (rn != NULL)); 1938 type_t *rettp = mp->m_returns_bool 1939 ? gettyp(Tflag ? BOOL : INT) : ln->tn_type; 1940 ntn = build_op(op, sys, rettp, ln, rn); 1941 break; 1942 } 1943 1944 if (ntn == NULL) 1945 return NULL; 1946 1947 if (mp->m_possible_precedence_confusion) 1948 check_precedence_confusion(ntn); 1949 1950 if (hflag && !suppress_constcond && 1951 mp->m_compares_with_zero && 1952 (ln->tn_op == CON || 1953 (mp->m_binary && op != QUEST && rn->tn_op == CON)) && 1954 /* XXX: rn->tn_system_dependent should be checked as well */ 1955 !ln->tn_system_dependent) 1956 /* constant in conditional context */ 1957 warning(161); 1958 1959 if (mp->m_fold_constant_operands && ln->tn_op == CON) { 1960 if (!mp->m_binary || rn->tn_op == CON) { 1961 if (mp->m_compares_with_zero) 1962 ntn = fold_constant_compare_zero(ntn); 1963 else if (is_floating(ntn->tn_type->t_tspec)) 1964 ntn = fold_constant_floating(ntn); 1965 else 1966 ntn = fold_constant_integer(ntn); 1967 } else if (op == QUEST) { 1968 lint_assert(has_operands(rn)); 1969 use(ln->u.value.u.integer != 0 1970 ? rn->u.ops.right : rn->u.ops.left); 1971 ntn = ln->u.value.u.integer != 0 1972 ? rn->u.ops.left : rn->u.ops.right; 1973 } 1974 } 1975 1976 return ntn; 1977 } 1978 1979 tnode_t * 1980 build_unary(op_t op, bool sys, tnode_t *tn) 1981 { 1982 return build_binary(tn, op, sys, NULL); 1983 } 1984 1985 static bool 1986 are_members_compatible(const sym_t *a, const sym_t *b) 1987 { 1988 if (a->u.s_member.sm_offset_in_bits != b->u.s_member.sm_offset_in_bits) 1989 return false; 1990 1991 const type_t *atp = a->s_type; 1992 const type_t *btp = b->s_type; 1993 bool w = false; 1994 if (!types_compatible(atp, btp, false, false, &w) && !w) 1995 return false; 1996 if (a->s_bitfield != b->s_bitfield) 1997 return false; 1998 if (a->s_bitfield) { 1999 if (atp->t_bit_field_width != btp->t_bit_field_width) 2000 return false; 2001 if (atp->t_bit_field_offset != btp->t_bit_field_offset) 2002 return false; 2003 } 2004 return true; 2005 } 2006 2007 /* 2008 * Return whether all struct/union members with the same name have the same 2009 * type and offset. 2010 */ 2011 static bool 2012 all_members_compatible(const sym_t *msym) 2013 { 2014 for (const sym_t *csym = msym; 2015 csym != NULL; csym = csym->s_symtab_next) { 2016 if (!is_member(csym)) 2017 continue; 2018 if (strcmp(msym->s_name, csym->s_name) != 0) 2019 continue; 2020 2021 for (const sym_t *sym = csym->s_symtab_next; 2022 sym != NULL; sym = sym->s_symtab_next) { 2023 if (is_member(sym) 2024 && strcmp(csym->s_name, sym->s_name) == 0 2025 && !are_members_compatible(csym, sym)) 2026 return false; 2027 } 2028 } 2029 return true; 2030 } 2031 2032 sym_t * 2033 find_member(const struct_or_union *sou, const char *name) 2034 { 2035 for (sym_t *mem = sou->sou_first_member; 2036 mem != NULL; mem = mem->s_next) { 2037 lint_assert(is_member(mem)); 2038 lint_assert(mem->u.s_member.sm_containing_type == sou); 2039 if (strcmp(mem->s_name, name) == 0) 2040 return mem; 2041 } 2042 2043 for (sym_t *mem = sou->sou_first_member; 2044 mem != NULL; mem = mem->s_next) { 2045 if (is_struct_or_union(mem->s_type->t_tspec) 2046 && mem->s_name == unnamed) { 2047 sym_t *nested_mem = 2048 find_member(mem->s_type->u.sou, name); 2049 if (nested_mem != NULL) 2050 return nested_mem; 2051 } 2052 } 2053 return NULL; 2054 } 2055 2056 /* 2057 * Remove the member if it was unknown until now, which means 2058 * that no defined struct or union has a member with the same name. 2059 */ 2060 static void 2061 remove_unknown_member(tnode_t *tn, sym_t *msym) 2062 { 2063 /* type '%s' does not have member '%s' */ 2064 error(101, type_name(tn->tn_type), msym->s_name); 2065 symtab_remove_forever(msym); 2066 msym->s_kind = SK_MEMBER; 2067 msym->s_scl = STRUCT_MEMBER; 2068 2069 struct_or_union *sou = expr_zero_alloc(sizeof(*sou), 2070 "struct_or_union"); 2071 sou->sou_tag = expr_zero_alloc(sizeof(*sou->sou_tag), "sym"); 2072 sou->sou_tag->s_name = unnamed; 2073 2074 msym->u.s_member.sm_containing_type = sou; 2075 /* 2076 * The member sm_offset_in_bits is not needed here since this symbol 2077 * can only be used for error reporting. 2078 */ 2079 } 2080 2081 /* 2082 * Returns a symbol which has the same name as 'msym' and is a member of the 2083 * struct or union specified by 'tn'. 2084 */ 2085 static sym_t * 2086 struct_or_union_member(tnode_t *tn, op_t op, sym_t *msym) 2087 { 2088 2089 /* Determine the tag type of which msym is expected to be a member. */ 2090 const type_t *tp = NULL; 2091 if (op == POINT && is_struct_or_union(tn->tn_type->t_tspec)) 2092 tp = tn->tn_type; 2093 if (op == ARROW && tn->tn_type->t_tspec == PTR 2094 && is_struct_or_union(tn->tn_type->t_subt->t_tspec)) 2095 tp = tn->tn_type->t_subt; 2096 struct_or_union *sou = tp != NULL ? tp->u.sou : NULL; 2097 2098 if (sou != NULL) { 2099 sym_t *nested_mem = find_member(sou, msym->s_name); 2100 if (nested_mem != NULL) 2101 return nested_mem; 2102 } 2103 2104 if (msym->s_scl == NO_SCL) { 2105 remove_unknown_member(tn, msym); 2106 return msym; 2107 } 2108 2109 bool eq = all_members_compatible(msym); 2110 2111 /* 2112 * Now handle the case in which the left operand refers really to a 2113 * struct/union, but the right operand is not member of it. 2114 */ 2115 if (sou != NULL) { 2116 if (eq && !allow_c90) 2117 /* illegal use of member '%s' */ 2118 warning(102, msym->s_name); 2119 else 2120 /* illegal use of member '%s' */ 2121 error(102, msym->s_name); 2122 return msym; 2123 } 2124 2125 if (eq) { 2126 if (op == POINT) { 2127 if (!allow_c90) 2128 /* left operand of '.' must be struct ... */ 2129 warning(103, type_name(tn->tn_type)); 2130 else 2131 /* left operand of '.' must be struct ... */ 2132 error(103, type_name(tn->tn_type)); 2133 } else { 2134 if (!allow_c90 && tn->tn_type->t_tspec == PTR) 2135 /* left operand of '->' must be pointer ... */ 2136 warning(104, type_name(tn->tn_type)); 2137 else 2138 /* left operand of '->' must be pointer ... */ 2139 error(104, type_name(tn->tn_type)); 2140 } 2141 } else { 2142 if (!allow_c90) 2143 /* non-unique member requires struct/union %s */ 2144 error(105, op == POINT ? "object" : "pointer"); 2145 else 2146 /* unacceptable operand of '%s' */ 2147 error(111, op_name(op)); 2148 } 2149 2150 return msym; 2151 } 2152 2153 tnode_t * 2154 build_member_access(tnode_t *ln, op_t op, bool sys, sbuf_t *member) 2155 { 2156 sym_t *msym; 2157 2158 if (ln == NULL) 2159 return NULL; 2160 2161 if (op == ARROW) 2162 /* must do this before struct_or_union_member is called */ 2163 ln = cconv(ln); 2164 msym = struct_or_union_member(ln, op, getsym(member)); 2165 return build_binary(ln, op, sys, build_name(msym, false)); 2166 } 2167 2168 /* 2169 * Perform class conversions. 2170 * 2171 * Arrays of type T are converted into pointers to type T. 2172 * Functions are converted to pointers to functions. 2173 * Lvalues are converted to rvalues. 2174 * 2175 * C99 6.3 "Conversions" 2176 * C99 6.3.2 "Other operands" 2177 * C99 6.3.2.1 "Lvalues, arrays, and function designators" 2178 */ 2179 tnode_t * 2180 cconv(tnode_t *tn) 2181 { 2182 if (tn->tn_type->t_tspec == ARRAY) { 2183 if (!tn->tn_lvalue) { 2184 /* XXX print correct operator */ 2185 /* %soperand of '%s' must be lvalue */ 2186 gnuism(114, "", op_name(ADDR)); 2187 } 2188 tn = build_op(ADDR, tn->tn_sys, 2189 expr_derive_type(tn->tn_type->t_subt, PTR), tn, NULL); 2190 } 2191 2192 if (tn->tn_type->t_tspec == FUNC) 2193 tn = build_address(tn->tn_sys, tn, true); 2194 2195 if (tn->tn_lvalue) { 2196 type_t *tp = expr_dup_type(tn->tn_type); 2197 /* C99 6.3.2.1p2 sentence 2 says to remove the qualifiers. */ 2198 tp->t_const = tp->t_volatile = false; 2199 tn = build_op(LOAD, tn->tn_sys, tp, tn, NULL); 2200 } 2201 2202 return tn; 2203 } 2204 2205 const tnode_t * 2206 before_conversion(const tnode_t *tn) 2207 { 2208 while (tn->tn_op == CVT && !tn->tn_cast) 2209 tn = tn->u.ops.left; 2210 return tn; 2211 } 2212 2213 /* 2214 * Most errors required by C90 are reported in struct_or_union_member(). 2215 * Here we only check for totally wrong things. 2216 */ 2217 static bool 2218 typeok_point(const tnode_t *ln, const type_t *ltp, tspec_t lt) 2219 { 2220 if (is_struct_or_union(lt)) 2221 return true; 2222 2223 if (lt == FUNC || lt == VOID || ltp->t_bitfield) 2224 goto wrong; 2225 2226 /* 2227 * Some C dialects from before C90 tolerated any lvalue on the 2228 * left-hand side of the '.' operator, allowing things like 'char 2229 * st[100]; st.st_mtime', assuming that the member 'st_mtime' only 2230 * occurred in a single struct; see typeok_arrow. 2231 */ 2232 if (ln->tn_lvalue) 2233 return true; 2234 2235 wrong: 2236 /* With allow_c90 we already got an error */ 2237 if (!allow_c90) 2238 /* unacceptable operand of '%s' */ 2239 error(111, op_name(POINT)); 2240 2241 return false; 2242 } 2243 2244 static bool 2245 typeok_arrow(tspec_t lt) 2246 { 2247 /* 2248 * C1978 Appendix A 14.1 says: <quote>In fact, any lvalue is allowed 2249 * before '.', and that lvalue is then assumed to have the form of the 2250 * structure of which the name of the right is a member. [...] Such 2251 * constructions are non-portable.</quote> 2252 */ 2253 if (lt == PTR || (!allow_c90 && is_integer(lt))) 2254 return true; 2255 2256 /* With allow_c90 we already got an error */ 2257 if (!allow_c90) 2258 /* unacceptable operand of '%s' */ 2259 error(111, op_name(ARROW)); 2260 return false; 2261 } 2262 2263 static bool 2264 typeok_incdec(op_t op, const tnode_t *tn, const type_t *tp) 2265 { 2266 /* operand has scalar type (checked in typeok) */ 2267 if (!tn->tn_lvalue) { 2268 if (tn->tn_op == CVT && tn->tn_cast && 2269 tn->u.ops.left->tn_op == LOAD) 2270 /* a cast does not yield an lvalue */ 2271 error(163); 2272 /* %soperand of '%s' must be lvalue */ 2273 error(114, "", op_name(op)); 2274 return false; 2275 } 2276 if (tp->t_const && allow_c90) 2277 /* %soperand of '%s' must be modifiable lvalue */ 2278 warning(115, "", op_name(op)); 2279 return true; 2280 } 2281 2282 static bool 2283 typeok_address(op_t op, const tnode_t *tn, const type_t *tp, tspec_t t) 2284 { 2285 if (t == ARRAY || t == FUNC) { 2286 /* ok, a warning comes later (in build_address()) */ 2287 } else if (!tn->tn_lvalue) { 2288 if (tn->tn_op == CVT && tn->tn_cast && 2289 tn->u.ops.left->tn_op == LOAD) 2290 /* a cast does not yield an lvalue */ 2291 error(163); 2292 /* %soperand of '%s' must be lvalue */ 2293 error(114, "", op_name(op)); 2294 return false; 2295 } else if (is_scalar(t)) { 2296 if (tp->t_bitfield) { 2297 /* cannot take address of bit-field */ 2298 error(112); 2299 return false; 2300 } 2301 } else if (t != STRUCT && t != UNION) { 2302 /* unacceptable operand of '%s' */ 2303 error(111, op_name(op)); 2304 return false; 2305 } 2306 if (tn->tn_op == NAME && tn->u.sym->s_register) { 2307 /* cannot take address of register '%s' */ 2308 error(113, tn->u.sym->s_name); 2309 return false; 2310 } 2311 return true; 2312 } 2313 2314 static bool 2315 typeok_indir(const type_t *tp, tspec_t t) 2316 { 2317 2318 if (t != PTR) { 2319 /* cannot dereference non-pointer type '%s' */ 2320 error(96, type_name(tp)); 2321 return false; 2322 } 2323 return true; 2324 } 2325 2326 static void 2327 warn_incompatible_types(op_t op, 2328 const type_t *ltp, tspec_t lt, 2329 const type_t *rtp, tspec_t rt) 2330 { 2331 bool binary = modtab[op].m_binary; 2332 2333 if (lt == VOID || (binary && rt == VOID)) { 2334 /* void type illegal in expression */ 2335 error(109); 2336 } else if (op == ASSIGN) 2337 /* cannot assign to '%s' from '%s' */ 2338 error(171, type_name(ltp), type_name(rtp)); 2339 else if (binary) 2340 /* operands of '%s' have incompatible types '%s' and '%s' */ 2341 error(107, op_name(op), type_name(ltp), type_name(rtp)); 2342 else { 2343 lint_assert(rt == NO_TSPEC); 2344 /* operand of '%s' has invalid type '%s' */ 2345 error(108, op_name(op), type_name(ltp)); 2346 } 2347 } 2348 2349 static bool 2350 typeok_plus(op_t op, 2351 const type_t *ltp, tspec_t lt, 2352 const type_t *rtp, tspec_t rt) 2353 { 2354 /* operands have scalar types (checked in typeok) */ 2355 if ((lt == PTR && !is_integer(rt)) || (rt == PTR && !is_integer(lt))) { 2356 warn_incompatible_types(op, ltp, lt, rtp, rt); 2357 return false; 2358 } 2359 return true; 2360 } 2361 2362 static bool 2363 typeok_minus(op_t op, 2364 const type_t *ltp, tspec_t lt, 2365 const type_t *rtp, tspec_t rt) 2366 { 2367 /* operands have scalar types (checked in typeok) */ 2368 if ((lt == PTR && rt != PTR && !is_integer(rt)) || 2369 (lt != PTR && rt == PTR)) { 2370 warn_incompatible_types(op, ltp, lt, rtp, rt); 2371 return false; 2372 } 2373 if (lt == PTR && rt == PTR && 2374 !types_compatible(ltp->t_subt, rtp->t_subt, true, false, NULL)) { 2375 /* illegal pointer subtraction */ 2376 error(116); 2377 } 2378 return true; 2379 } 2380 2381 static void 2382 typeok_shr(op_t op, 2383 const tnode_t *ln, tspec_t lt, 2384 const tnode_t *rn, tspec_t rt) 2385 { 2386 tspec_t olt = before_conversion(ln)->tn_type->t_tspec; 2387 tspec_t ort = before_conversion(rn)->tn_type->t_tspec; 2388 2389 /* operands have integer types (checked in typeok) */ 2390 if (pflag && !is_uinteger(olt)) { 2391 integer_constraints lc = ic_expr(ln); 2392 if (!ic_maybe_signed(ln->tn_type, &lc)) 2393 return; 2394 2395 if (ln->tn_op != CON) 2396 /* bitwise '%s' on signed value possibly nonportable */ 2397 warning(117, op_name(op)); 2398 else if (ln->u.value.u.integer < 0) 2399 /* bitwise '%s' on signed value nonportable */ 2400 warning(120, op_name(op)); 2401 } else if (allow_trad && allow_c90 && 2402 !is_uinteger(olt) && is_uinteger(ort)) { 2403 /* The left operand would become unsigned in traditional C. */ 2404 if (hflag && (ln->tn_op != CON || ln->u.value.u.integer < 0)) { 2405 /* semantics of '%s' change in C90; use ... */ 2406 warning(118, op_name(op)); 2407 } 2408 } else if (allow_trad && allow_c90 && 2409 !is_uinteger(olt) && !is_uinteger(ort) && 2410 portable_rank_cmp(lt, rt) < 0) { 2411 /* 2412 * In traditional C, the left operand would be extended 2413 * (possibly sign-extended) and then shifted. 2414 */ 2415 if (hflag && (ln->tn_op != CON || ln->u.value.u.integer < 0)) { 2416 /* semantics of '%s' change in C90; use ... */ 2417 warning(118, op_name(op)); 2418 } 2419 } 2420 } 2421 2422 static void 2423 typeok_shl(op_t op, tspec_t lt, tspec_t rt) 2424 { 2425 /* 2426 * C90 does not perform balancing for shift operations, but traditional 2427 * C does. If the width of the right operand is greater than the width 2428 * of the left operand, then in traditional C the left operand would be 2429 * extended to the width of the right operand. For SHL this may result 2430 * in different results. 2431 */ 2432 if (portable_rank_cmp(lt, rt) < 0) { 2433 /* 2434 * XXX If both operands are constant, make sure that there is 2435 * really a difference between C90 and traditional C. 2436 */ 2437 if (hflag && allow_trad && allow_c90) 2438 /* semantics of '%s' change in C90; use ... */ 2439 warning(118, op_name(op)); 2440 } 2441 } 2442 2443 static void 2444 typeok_shift(const type_t *ltp, tspec_t lt, const tnode_t *rn, tspec_t rt) 2445 { 2446 if (rn->tn_op != CON) 2447 return; 2448 2449 if (!is_uinteger(rt) && rn->u.value.u.integer < 0) 2450 /* negative shift */ 2451 warning(121); 2452 else if ((uint64_t)rn->u.value.u.integer == size_in_bits(lt)) 2453 /* shift amount %u equals bit-size of '%s' */ 2454 warning(267, (unsigned)rn->u.value.u.integer, type_name(ltp)); 2455 else if ((uint64_t)rn->u.value.u.integer > size_in_bits(lt)) { 2456 /* shift amount %llu is greater than bit-size %llu of '%s' */ 2457 warning(122, (unsigned long long)rn->u.value.u.integer, 2458 (unsigned long long)size_in_bits(lt), 2459 tspec_name(lt)); 2460 } 2461 } 2462 2463 static bool 2464 is_typeok_eq(const tnode_t *ln, tspec_t lt, const tnode_t *rn, tspec_t rt) 2465 { 2466 if (lt == PTR && is_null_pointer(rn)) 2467 return true; 2468 if (rt == PTR && is_null_pointer(ln)) 2469 return true; 2470 return false; 2471 } 2472 2473 static void 2474 warn_incompatible_pointers(op_t op, const type_t *ltp, const type_t *rtp) 2475 { 2476 lint_assert(ltp->t_tspec == PTR); 2477 lint_assert(rtp->t_tspec == PTR); 2478 2479 tspec_t lt = ltp->t_subt->t_tspec; 2480 tspec_t rt = rtp->t_subt->t_tspec; 2481 2482 if (is_struct_or_union(lt) && is_struct_or_union(rt)) { 2483 if (op == RETURN) 2484 /* illegal structure pointer combination */ 2485 warning(244); 2486 else { 2487 /* incompatible structure pointers: '%s' '%s' '%s' */ 2488 warning(245, type_name(ltp), 2489 op_name(op), type_name(rtp)); 2490 } 2491 } else { 2492 if (op == RETURN) 2493 /* illegal combination of '%s' and '%s' */ 2494 warning(184, type_name(ltp), type_name(rtp)); 2495 else { 2496 /* illegal combination of '%s' and '%s', op '%s' */ 2497 warning(124, 2498 type_name(ltp), type_name(rtp), op_name(op)); 2499 } 2500 } 2501 } 2502 2503 static void 2504 check_pointer_comparison(op_t op, const tnode_t *ln, const tnode_t *rn) 2505 { 2506 type_t *ltp = ln->tn_type, *rtp = rn->tn_type; 2507 tspec_t lst = ltp->t_subt->t_tspec, rst = rtp->t_subt->t_tspec; 2508 2509 if (lst == VOID || rst == VOID) { 2510 /* TODO: C99 behaves like C90 here. */ 2511 if (!allow_trad && !allow_c99 && 2512 (lst == FUNC || rst == FUNC)) { 2513 /* (void *)0 is already handled in typeok() */ 2514 const char *lsts, *rsts; 2515 *(lst == FUNC ? &lsts : &rsts) = "function pointer"; 2516 *(lst == VOID ? &lsts : &rsts) = "'void *'"; 2517 /* C90 or later forbid comparison of %s with %s */ 2518 warning(274, lsts, rsts); 2519 } 2520 return; 2521 } 2522 2523 if (!types_compatible(ltp->t_subt, rtp->t_subt, true, false, NULL)) { 2524 warn_incompatible_pointers(op, ltp, rtp); 2525 return; 2526 } 2527 2528 if (lst == FUNC && rst == FUNC) { 2529 /* TODO: C99 behaves like C90 here, see C99 6.5.8p2. */ 2530 if (!allow_trad && !allow_c99 && op != EQ && op != NE) 2531 /* pointers to functions can only be compared ... */ 2532 warning(125); 2533 } 2534 } 2535 2536 static bool 2537 typeok_compare(op_t op, 2538 const tnode_t *ln, const type_t *ltp, tspec_t lt, 2539 const tnode_t *rn, const type_t *rtp, tspec_t rt) 2540 { 2541 if (lt == PTR && rt == PTR) { 2542 check_pointer_comparison(op, ln, rn); 2543 return true; 2544 } 2545 2546 if (lt != PTR && rt != PTR) 2547 return true; 2548 2549 if (!is_integer(lt) && !is_integer(rt)) { 2550 warn_incompatible_types(op, ltp, lt, rtp, rt); 2551 return false; 2552 } 2553 2554 const char *lx = lt == PTR ? "pointer" : "integer"; 2555 const char *rx = rt == PTR ? "pointer" : "integer"; 2556 /* illegal combination of %s '%s' and %s '%s', op '%s' */ 2557 warning(123, lx, type_name(ltp), rx, type_name(rtp), op_name(op)); 2558 return true; 2559 } 2560 2561 static bool 2562 typeok_quest(tspec_t lt, const tnode_t *rn) 2563 { 2564 if (!is_scalar(lt)) { 2565 /* first operand of '?' must have scalar type */ 2566 error(170); 2567 return false; 2568 } 2569 lint_assert(before_conversion(rn)->tn_op == COLON); 2570 return true; 2571 } 2572 2573 static void 2574 typeok_colon_pointer(const type_t *ltp, const type_t *rtp) 2575 { 2576 type_t *lstp = ltp->t_subt; 2577 type_t *rstp = rtp->t_subt; 2578 tspec_t lst = lstp->t_tspec; 2579 tspec_t rst = rstp->t_tspec; 2580 2581 if ((lst == VOID && rst == FUNC) || (lst == FUNC && rst == VOID)) { 2582 /* (void *)0 is handled in typeok_colon */ 2583 /* TODO: C99 behaves like C90 here. */ 2584 if (!allow_trad && !allow_c99) 2585 /* conversion of %s to %s requires a cast, op %s */ 2586 warning(305, "function pointer", "'void *'", 2587 op_name(COLON)); 2588 return; 2589 } 2590 2591 if (pointer_types_are_compatible(lstp, rstp, true)) 2592 return; 2593 if (!types_compatible(lstp, rstp, true, false, NULL)) 2594 warn_incompatible_pointers(COLON, ltp, rtp); 2595 } 2596 2597 static bool 2598 typeok_colon(const tnode_t *ln, const type_t *ltp, tspec_t lt, 2599 const tnode_t *rn, const type_t *rtp, tspec_t rt) 2600 { 2601 2602 if (is_arithmetic(lt) && is_arithmetic(rt)) 2603 return true; 2604 if (lt == BOOL && rt == BOOL) 2605 return true; 2606 2607 if (lt == STRUCT && rt == STRUCT && ltp->u.sou == rtp->u.sou) 2608 return true; 2609 if (lt == UNION && rt == UNION && ltp->u.sou == rtp->u.sou) 2610 return true; 2611 2612 if (lt == PTR && is_null_pointer(rn)) 2613 return true; 2614 if (rt == PTR && is_null_pointer(ln)) 2615 return true; 2616 2617 if ((lt == PTR && is_integer(rt)) || (is_integer(lt) && rt == PTR)) { 2618 const char *lx = lt == PTR ? "pointer" : "integer"; 2619 const char *rx = rt == PTR ? "pointer" : "integer"; 2620 /* illegal combination of %s '%s' and %s '%s', op '%s' */ 2621 warning(123, lx, type_name(ltp), 2622 rx, type_name(rtp), op_name(COLON)); 2623 return true; 2624 } 2625 2626 if (lt == VOID || rt == VOID) { 2627 if (lt != VOID || rt != VOID) 2628 /* incompatible types '%s' and '%s' in conditional */ 2629 warning(126, type_name(ltp), type_name(rtp)); 2630 return true; 2631 } 2632 2633 if (lt == PTR && rt == PTR) { 2634 typeok_colon_pointer(ltp, rtp); 2635 return true; 2636 } 2637 2638 /* incompatible types '%s' and '%s' in conditional */ 2639 error(126, type_name(ltp), type_name(rtp)); 2640 return false; 2641 } 2642 2643 static bool 2644 has_constant_member(const type_t *tp) 2645 { 2646 lint_assert(is_struct_or_union(tp->t_tspec)); 2647 2648 for (sym_t *m = tp->u.sou->sou_first_member; 2649 m != NULL; m = m->s_next) { 2650 const type_t *mtp = m->s_type; 2651 if (mtp->t_const) 2652 return true; 2653 if (is_struct_or_union(mtp->t_tspec) && 2654 has_constant_member(mtp)) 2655 return true; 2656 } 2657 return false; 2658 } 2659 2660 static bool 2661 typeok_assign(op_t op, const tnode_t *ln, const type_t *ltp, tspec_t lt) 2662 { 2663 if (op == RETURN || op == INIT || op == FARG) 2664 return true; 2665 2666 if (!ln->tn_lvalue) { 2667 if (ln->tn_op == CVT && ln->tn_cast && 2668 ln->u.ops.left->tn_op == LOAD) 2669 /* a cast does not yield an lvalue */ 2670 error(163); 2671 /* %soperand of '%s' must be lvalue */ 2672 error(114, "left ", op_name(op)); 2673 return false; 2674 } else if (ltp->t_const 2675 || (is_struct_or_union(lt) && has_constant_member(ltp))) { 2676 if (allow_c90) 2677 /* %soperand of '%s' must be modifiable lvalue */ 2678 warning(115, "left ", op_name(op)); 2679 } 2680 return true; 2681 } 2682 2683 static bool 2684 typeok_scalar(op_t op, const mod_t *mp, 2685 const type_t *ltp, tspec_t lt, 2686 const type_t *rtp, tspec_t rt) 2687 { 2688 if (mp->m_takes_bool && lt == BOOL && rt == BOOL) 2689 return true; 2690 if (mp->m_requires_integer) { 2691 if (!is_integer(lt) || (mp->m_binary && !is_integer(rt))) { 2692 warn_incompatible_types(op, ltp, lt, rtp, rt); 2693 return false; 2694 } 2695 } else if (mp->m_requires_integer_or_complex) { 2696 if ((!is_integer(lt) && !is_complex(lt)) || 2697 (mp->m_binary && (!is_integer(rt) && !is_complex(rt)))) { 2698 warn_incompatible_types(op, ltp, lt, rtp, rt); 2699 return false; 2700 } 2701 } else if (mp->m_requires_scalar) { 2702 if (!is_scalar(lt) || (mp->m_binary && !is_scalar(rt))) { 2703 warn_incompatible_types(op, ltp, lt, rtp, rt); 2704 return false; 2705 } 2706 } else if (mp->m_requires_arith) { 2707 if (!is_arithmetic(lt) || 2708 (mp->m_binary && !is_arithmetic(rt))) { 2709 warn_incompatible_types(op, ltp, lt, rtp, rt); 2710 return false; 2711 } 2712 } 2713 return true; 2714 } 2715 2716 static void 2717 check_assign_void_pointer(op_t op, int arg, 2718 tspec_t lt, tspec_t lst, 2719 tspec_t rt, tspec_t rst) 2720 { 2721 2722 if (!(lt == PTR && rt == PTR && (lst == VOID || rst == VOID))) 2723 return; 2724 /* two pointers, at least one pointer to void */ 2725 2726 /* TODO: C99 behaves like C90 here. */ 2727 if (!(!allow_trad && !allow_c99 && (lst == FUNC || rst == FUNC))) 2728 return; 2729 /* comb. of ptr to func and ptr to void */ 2730 2731 const char *lts, *rts; 2732 *(lst == FUNC ? <s : &rts) = "function pointer"; 2733 *(lst == VOID ? <s : &rts) = "'void *'"; 2734 2735 switch (op) { 2736 case INIT: 2737 case RETURN: 2738 /* conversion of %s to %s requires a cast */ 2739 warning(303, rts, lts); 2740 break; 2741 case FARG: 2742 /* conversion of %s to %s requires a cast, arg #%d */ 2743 warning(304, rts, lts, arg); 2744 break; 2745 default: 2746 /* conversion of %s to %s requires a cast, op %s */ 2747 warning(305, rts, lts, op_name(op)); 2748 break; 2749 } 2750 } 2751 2752 static bool 2753 is_direct_function_call(const tnode_t *tn, const char **out_name) 2754 { 2755 2756 if (tn->tn_op == CALL 2757 && tn->u.call->func->tn_op == ADDR 2758 && tn->u.call->func->u.ops.left->tn_op == NAME) { 2759 *out_name = tn->u.call->func->u.ops.left->u.sym->s_name; 2760 return true; 2761 } 2762 return false; 2763 } 2764 2765 static bool 2766 is_unconst_function(const char *name) 2767 { 2768 2769 return strcmp(name, "memchr") == 0 || 2770 strcmp(name, "strchr") == 0 || 2771 strcmp(name, "strpbrk") == 0 || 2772 strcmp(name, "strrchr") == 0 || 2773 strcmp(name, "strstr") == 0; 2774 } 2775 2776 static bool 2777 is_const_char_pointer(const tnode_t *tn) 2778 { 2779 /* 2780 * For traditional reasons, C99 6.4.5p5 defines that string literals 2781 * have type 'char[]'. They are often implicitly converted to 'char 2782 * *', for example when they are passed as function arguments. 2783 * 2784 * C99 6.4.5p6 further defines that modifying a string that is 2785 * constructed from a string literal invokes undefined behavior. 2786 * 2787 * Out of these reasons, string literals are treated as 'effectively 2788 * const' here. 2789 */ 2790 if (tn->tn_op == CVT && 2791 tn->u.ops.left->tn_op == ADDR && 2792 tn->u.ops.left->u.ops.left->tn_op == STRING) 2793 return true; 2794 2795 const type_t *tp = before_conversion(tn)->tn_type; 2796 return tp->t_tspec == PTR && 2797 tp->t_subt->t_tspec == CHAR && 2798 tp->t_subt->t_const; 2799 } 2800 2801 static bool 2802 is_const_pointer(const tnode_t *tn) 2803 { 2804 const type_t *tp = before_conversion(tn)->tn_type; 2805 return tp->t_tspec == PTR && tp->t_subt->t_const; 2806 } 2807 2808 static void 2809 check_unconst_function(const type_t *lstp, const tnode_t *rn) 2810 { 2811 const char *function_name; 2812 2813 if (lstp->t_tspec == CHAR && !lstp->t_const && 2814 is_direct_function_call(rn, &function_name) && 2815 is_unconst_function(function_name) && 2816 rn->u.call->args_len >= 1 && 2817 is_const_char_pointer(rn->u.call->args[0])) { 2818 /* call to '%s' effectively discards 'const' from argument */ 2819 warning(346, function_name); 2820 } 2821 2822 if (!lstp->t_const && 2823 is_direct_function_call(rn, &function_name) && 2824 strcmp(function_name, "bsearch") == 0 && 2825 rn->u.call->args_len >= 2 && 2826 is_const_pointer(rn->u.call->args[1])) { 2827 /* call to '%s' effectively discards 'const' from argument */ 2828 warning(346, function_name); 2829 } 2830 } 2831 2832 static bool 2833 check_assign_void_pointer_compat(op_t op, int arg, 2834 tspec_t lt, 2835 const type_t *lstp, tspec_t lst, 2836 const tnode_t *rn, 2837 const type_t *rtp, tspec_t rt, 2838 const type_t *rstp, tspec_t rst) 2839 { 2840 if (!(lt == PTR && rt == PTR && (lst == VOID || rst == VOID || 2841 types_compatible(lstp, rstp, 2842 true, false, NULL)))) 2843 return false; 2844 2845 /* compatible pointer types (qualifiers ignored) */ 2846 char qualifiers[32]; 2847 snprintf(qualifiers, sizeof(qualifiers), "%s%s", 2848 !lstp->t_const && rstp->t_const ? " const" : "", 2849 !lstp->t_volatile && rstp->t_volatile ? " volatile" : ""); 2850 if (allow_c90 && qualifiers[0] != '\0') { 2851 switch (op) { 2852 case INIT: 2853 case RETURN: 2854 /* '%s' discards '%s' from '%s' */ 2855 warning(182, op_name(op), 2856 qualifiers + 1, type_name(rtp)); 2857 break; 2858 case FARG: 2859 /* passing '%s' to argument %d discards '%s' */ 2860 warning(383, type_name(rtp), arg, qualifiers + 1); 2861 break; 2862 default: 2863 /* operator '%s' discards '%s' from '%s' */ 2864 warning(128, op_name(op), 2865 qualifiers + 1, type_name(rtp)); 2866 break; 2867 } 2868 } 2869 2870 if (allow_c90) 2871 check_unconst_function(lstp, rn); 2872 2873 return true; 2874 } 2875 2876 static bool 2877 check_assign_pointer_integer(op_t op, int arg, 2878 const type_t *ltp, tspec_t lt, 2879 const type_t *rtp, tspec_t rt) 2880 { 2881 2882 if (!((lt == PTR && is_integer(rt)) || (is_integer(lt) && rt == PTR))) 2883 return false; 2884 2885 const char *lx = lt == PTR ? "pointer" : "integer"; 2886 const char *rx = rt == PTR ? "pointer" : "integer"; 2887 2888 switch (op) { 2889 case INIT: 2890 case RETURN: 2891 /* illegal combination of %s '%s' and %s '%s' */ 2892 warning(183, lx, type_name(ltp), rx, type_name(rtp)); 2893 break; 2894 case FARG: 2895 /* illegal combination of %s '%s' and %s '%s', arg #%d */ 2896 warning(154, 2897 lx, type_name(ltp), rx, type_name(rtp), arg); 2898 break; 2899 default: 2900 /* illegal combination of %s '%s' and %s '%s', op '%s' */ 2901 warning(123, 2902 lx, type_name(ltp), rx, type_name(rtp), op_name(op)); 2903 break; 2904 } 2905 return true; 2906 } 2907 2908 static bool 2909 check_assign_pointer(op_t op, int arg, 2910 const type_t *ltp, tspec_t lt, 2911 const type_t *rtp, tspec_t rt) 2912 { 2913 if (!(lt == PTR && rt == PTR)) 2914 return false; 2915 2916 if (op == FARG) 2917 /* converting '%s' to incompatible '%s' for ... */ 2918 warning(153, type_name(rtp), type_name(ltp), arg); 2919 else 2920 warn_incompatible_pointers(op, ltp, rtp); 2921 return true; 2922 } 2923 2924 static void 2925 warn_assign(op_t op, int arg, 2926 const type_t *ltp, tspec_t lt, 2927 const type_t *rtp, tspec_t rt) 2928 { 2929 switch (op) { 2930 case INIT: 2931 /* cannot initialize '%s' from '%s' */ 2932 error(185, type_name(ltp), type_name(rtp)); 2933 break; 2934 case RETURN: 2935 /* function has return type '%s' but returns '%s' */ 2936 error(211, type_name(ltp), type_name(rtp)); 2937 break; 2938 case FARG: 2939 /* passing '%s' to incompatible '%s', arg #%d */ 2940 warning(155, type_name(rtp), type_name(ltp), arg); 2941 break; 2942 default: 2943 warn_incompatible_types(op, ltp, lt, rtp, rt); 2944 break; 2945 } 2946 } 2947 2948 /* 2949 * Checks type compatibility for ASSIGN, INIT, FARG and RETURN 2950 * and prints warnings/errors if necessary. 2951 * Returns whether the types are (almost) compatible. 2952 */ 2953 static bool 2954 check_assign_types_compatible(op_t op, int arg, 2955 const tnode_t *ln, const tnode_t *rn) 2956 { 2957 tspec_t lt, rt, lst = NO_TSPEC, rst = NO_TSPEC; 2958 type_t *ltp, *rtp, *lstp = NULL, *rstp = NULL; 2959 2960 if ((lt = (ltp = ln->tn_type)->t_tspec) == PTR) 2961 lst = (lstp = ltp->t_subt)->t_tspec; 2962 if ((rt = (rtp = rn->tn_type)->t_tspec) == PTR) 2963 rst = (rstp = rtp->t_subt)->t_tspec; 2964 2965 if (lt == BOOL && is_scalar(rt)) /* C99 6.3.1.2 */ 2966 return true; 2967 2968 if (is_arithmetic(lt) && (is_arithmetic(rt) || rt == BOOL)) 2969 return true; 2970 2971 if (is_struct_or_union(lt) && is_struct_or_union(rt)) 2972 return ltp->u.sou == rtp->u.sou; 2973 2974 if (lt == PTR && is_null_pointer(rn)) { 2975 if (is_integer(rn->tn_type->t_tspec)) 2976 /* implicit conversion from integer 0 to pointer ... */ 2977 query_message(15, type_name(ltp)); 2978 return true; 2979 } 2980 2981 check_assign_void_pointer(op, arg, lt, lst, rt, rst); 2982 2983 if (check_assign_void_pointer_compat(op, arg, 2984 lt, lstp, lst, rn, rtp, rt, rstp, rst)) 2985 return true; 2986 2987 if (check_assign_pointer_integer(op, arg, ltp, lt, rtp, rt)) 2988 return true; 2989 2990 if (check_assign_pointer(op, arg, ltp, lt, rtp, rt)) 2991 return true; 2992 2993 warn_assign(op, arg, ltp, lt, rtp, rt); 2994 return false; 2995 } 2996 2997 static bool 2998 has_side_effect(const tnode_t *tn) /* NOLINT(misc-no-recursion) */ 2999 { 3000 op_t op = tn->tn_op; 3001 3002 if (modtab[op].m_has_side_effect) 3003 return true; 3004 3005 if (op == CVT && tn->tn_type->t_tspec == VOID) 3006 return has_side_effect(tn->u.ops.left); 3007 3008 /* XXX: Why not has_side_effect(tn->u.ops.left) as well? */ 3009 if (op == LOGAND || op == LOGOR) 3010 return has_side_effect(tn->u.ops.right); 3011 3012 /* XXX: Why not has_side_effect(tn->u.ops.left) as well? */ 3013 if (op == QUEST) 3014 return has_side_effect(tn->u.ops.right); 3015 3016 if (op == COLON || op == COMMA) { 3017 return has_side_effect(tn->u.ops.left) || 3018 has_side_effect(tn->u.ops.right); 3019 } 3020 3021 return false; 3022 } 3023 3024 static bool 3025 is_void_cast(const tnode_t *tn) 3026 { 3027 3028 return tn->tn_op == CVT && tn->tn_cast && 3029 tn->tn_type->t_tspec == VOID; 3030 } 3031 3032 static bool 3033 is_local_symbol(const tnode_t *tn) 3034 { 3035 3036 return tn->tn_op == LOAD && 3037 tn->u.ops.left->tn_op == NAME && 3038 tn->u.ops.left->u.sym->s_scl == AUTO; 3039 } 3040 3041 static bool 3042 is_int_constant_zero(const tnode_t *tn) 3043 { 3044 3045 return tn->tn_op == CON && 3046 tn->tn_type->t_tspec == INT && 3047 tn->u.value.u.integer == 0; 3048 } 3049 3050 static void 3051 check_null_effect(const tnode_t *tn) 3052 { 3053 3054 if (hflag && 3055 !has_side_effect(tn) && 3056 !(is_void_cast(tn) && is_local_symbol(tn->u.ops.left)) && 3057 !(is_void_cast(tn) && is_int_constant_zero(tn->u.ops.left))) { 3058 /* expression has null effect */ 3059 warning(129); 3060 } 3061 } 3062 3063 /* 3064 * Check the types for specific operators and type combinations. 3065 * 3066 * At this point, the operands already conform to the type requirements of 3067 * the operator, such as being integer, floating or scalar. 3068 */ 3069 static bool 3070 typeok_op(op_t op, int arg, 3071 const tnode_t *ln, const type_t *ltp, tspec_t lt, 3072 const tnode_t *rn, const type_t *rtp, tspec_t rt) 3073 { 3074 switch (op) { 3075 case ARROW: 3076 return typeok_arrow(lt); 3077 case POINT: 3078 return typeok_point(ln, ltp, lt); 3079 case INCBEF: 3080 case DECBEF: 3081 case INCAFT: 3082 case DECAFT: 3083 return typeok_incdec(op, ln, ltp); 3084 case INDIR: 3085 return typeok_indir(ltp, lt); 3086 case ADDR: 3087 return typeok_address(op, ln, ltp, lt); 3088 case PLUS: 3089 return typeok_plus(op, ltp, lt, rtp, rt); 3090 case MINUS: 3091 return typeok_minus(op, ltp, lt, rtp, rt); 3092 case SHL: 3093 typeok_shl(op, lt, rt); 3094 goto shift; 3095 case SHR: 3096 typeok_shr(op, ln, lt, rn, rt); 3097 shift: 3098 typeok_shift(ltp, lt, rn, rt); 3099 break; 3100 case LT: 3101 case LE: 3102 case GT: 3103 case GE: 3104 compare: 3105 return typeok_compare(op, ln, ltp, lt, rn, rtp, rt); 3106 case EQ: 3107 case NE: 3108 if (is_typeok_eq(ln, lt, rn, rt)) 3109 break; 3110 goto compare; 3111 case QUEST: 3112 return typeok_quest(lt, rn); 3113 case COLON: 3114 return typeok_colon(ln, ltp, lt, rn, rtp, rt); 3115 case ASSIGN: 3116 case INIT: 3117 case FARG: 3118 case RETURN: 3119 if (!check_assign_types_compatible(op, arg, ln, rn)) 3120 return false; 3121 goto assign; 3122 case MULASS: 3123 case DIVASS: 3124 case MODASS: 3125 goto assign; 3126 case ADDASS: 3127 case SUBASS: 3128 if ((lt == PTR && !is_integer(rt)) || rt == PTR) { 3129 warn_incompatible_types(op, ltp, lt, rtp, rt); 3130 return false; 3131 } 3132 goto assign; 3133 case SHLASS: 3134 goto assign; 3135 case SHRASS: 3136 if (pflag && !is_uinteger(lt) && 3137 !(!allow_c90 && is_uinteger(rt))) { 3138 /* bitwise '%s' on signed value possibly nonportable */ 3139 warning(117, op_name(op)); 3140 } 3141 goto assign; 3142 case ANDASS: 3143 case XORASS: 3144 case ORASS: 3145 assign: 3146 return typeok_assign(op, ln, ltp, lt); 3147 case COMMA: 3148 if (!modtab[ln->tn_op].m_has_side_effect) 3149 check_null_effect(ln); 3150 break; 3151 default: 3152 break; 3153 } 3154 return true; 3155 } 3156 3157 static void 3158 check_bad_enum_operation(op_t op, const tnode_t *ln, const tnode_t *rn) 3159 { 3160 3161 if (!eflag) 3162 return; 3163 3164 /* Allow enum in array indices. */ 3165 if (op == PLUS && 3166 ((ln->tn_type->t_is_enum && rn->tn_type->t_tspec == PTR) || 3167 (rn->tn_type->t_is_enum && ln->tn_type->t_tspec == PTR))) { 3168 return; 3169 } 3170 3171 /* dubious operation '%s' on enum */ 3172 warning(241, op_name(op)); 3173 } 3174 3175 static void 3176 check_enum_type_mismatch(op_t op, int arg, const tnode_t *ln, const tnode_t *rn) 3177 { 3178 const mod_t *mp = &modtab[op]; 3179 3180 if (ln->tn_type->u.enumer != rn->tn_type->u.enumer) { 3181 switch (op) { 3182 case INIT: 3183 /* enum type mismatch between '%s' and '%s' in ... */ 3184 warning(210, 3185 type_name(ln->tn_type), type_name(rn->tn_type)); 3186 break; 3187 case FARG: 3188 /* function expects '%s', passing '%s' for arg #%d */ 3189 warning(156, 3190 type_name(ln->tn_type), type_name(rn->tn_type), 3191 arg); 3192 break; 3193 case RETURN: 3194 /* function has return type '%s' but returns '%s' */ 3195 warning(211, 3196 type_name(ln->tn_type), type_name(rn->tn_type)); 3197 break; 3198 default: 3199 /* enum type mismatch: '%s' '%s' '%s' */ 3200 warning(130, type_name(ln->tn_type), op_name(op), 3201 type_name(rn->tn_type)); 3202 break; 3203 } 3204 } else if (Pflag && eflag && mp->m_comparison && op != EQ && op != NE) 3205 /* operator '%s' assumes that '%s' is ordered */ 3206 warning(243, op_name(op), type_name(ln->tn_type)); 3207 } 3208 3209 static void 3210 check_enum_int_mismatch(op_t op, int arg, const tnode_t *ln, const tnode_t *rn) 3211 { 3212 3213 if (!eflag) 3214 return; 3215 3216 switch (op) { 3217 case INIT: 3218 /* 3219 * Initialization with 0 is allowed. Otherwise, all implicit 3220 * initializations would need to be warned upon as well. 3221 */ 3222 if (!rn->tn_type->t_is_enum && rn->tn_op == CON && 3223 is_integer(rn->tn_type->t_tspec) && 3224 rn->u.value.u.integer == 0) { 3225 return; 3226 } 3227 /* initialization of '%s' with '%s' */ 3228 warning(277, type_name(ln->tn_type), type_name(rn->tn_type)); 3229 break; 3230 case FARG: 3231 /* combination of '%s' and '%s', arg #%d */ 3232 warning(278, 3233 type_name(ln->tn_type), type_name(rn->tn_type), arg); 3234 break; 3235 case RETURN: 3236 /* combination of '%s' and '%s' in return */ 3237 warning(279, type_name(ln->tn_type), type_name(rn->tn_type)); 3238 break; 3239 default: 3240 /* combination of '%s' and '%s', op '%s' */ 3241 warning(242, type_name(ln->tn_type), type_name(rn->tn_type), 3242 op_name(op)); 3243 break; 3244 } 3245 } 3246 3247 static void 3248 typeok_enum(op_t op, const mod_t *mp, int arg, 3249 const tnode_t *ln, const type_t *ltp, 3250 const tnode_t *rn, const type_t *rtp) 3251 { 3252 if (mp->m_bad_on_enum && 3253 (ltp->t_is_enum || (mp->m_binary && rtp->t_is_enum))) { 3254 check_bad_enum_operation(op, ln, rn); 3255 } else if (mp->m_valid_on_enum && 3256 (ltp->t_is_enum && rtp != NULL && rtp->t_is_enum)) { 3257 check_enum_type_mismatch(op, arg, ln, rn); 3258 } else if (mp->m_valid_on_enum && 3259 (ltp->t_is_enum || (rtp != NULL && rtp->t_is_enum))) { 3260 check_enum_int_mismatch(op, arg, ln, rn); 3261 } 3262 } 3263 3264 /* Perform most type checks. Return whether the types are ok. */ 3265 bool 3266 typeok(op_t op, int arg, const tnode_t *ln, const tnode_t *rn) 3267 { 3268 3269 const mod_t *mp = &modtab[op]; 3270 3271 type_t *ltp = ln->tn_type; 3272 tspec_t lt = ltp->t_tspec; 3273 3274 type_t *rtp = mp->m_binary ? rn->tn_type : NULL; 3275 tspec_t rt = mp->m_binary ? rtp->t_tspec : NO_TSPEC; 3276 3277 if (Tflag && !typeok_scalar_strict_bool(op, mp, arg, ln, rn)) 3278 return false; 3279 if (!typeok_scalar(op, mp, ltp, lt, rtp, rt)) 3280 return false; 3281 3282 if (!typeok_op(op, arg, ln, ltp, lt, rn, rtp, rt)) 3283 return false; 3284 3285 typeok_enum(op, mp, arg, ln, ltp, rn, rtp); 3286 return true; 3287 } 3288 3289 /* In traditional C, keep unsigned and promote FLOAT to DOUBLE. */ 3290 static tspec_t 3291 promote_trad(tspec_t t) 3292 { 3293 3294 if (t == UCHAR || t == USHORT) 3295 return UINT; 3296 if (t == CHAR || t == SCHAR || t == SHORT) 3297 return INT; 3298 if (t == FLOAT) 3299 return DOUBLE; 3300 if (t == ENUM) 3301 return INT; 3302 return t; 3303 } 3304 3305 /* 3306 * C99 6.3.1.1p2 requires for types with lower rank than int that "If an int 3307 * can represent all the values of the original type, the value is converted 3308 * to an int; otherwise it is converted to an unsigned int", and that "All 3309 * other types are unchanged by the integer promotions". 3310 */ 3311 static tspec_t 3312 promote_c90(const tnode_t *tn, tspec_t t, bool farg) 3313 { 3314 if (tn->tn_type->t_bitfield) { 3315 unsigned int width = tn->tn_type->t_bit_field_width; 3316 unsigned int int_width = size_in_bits(INT); 3317 // XXX: What about _Bool bit-fields, since C99? 3318 if (width < int_width) 3319 return INT; 3320 if (width == int_width) 3321 return is_uinteger(t) ? UINT : INT; 3322 return t; 3323 } 3324 3325 if (t == CHAR || t == SCHAR) 3326 return INT; 3327 if (t == UCHAR) 3328 return size_in_bits(CHAR) < size_in_bits(INT) ? INT : UINT; 3329 if (t == SHORT) 3330 return INT; 3331 if (t == USHORT) 3332 return size_in_bits(SHORT) < size_in_bits(INT) ? INT : UINT; 3333 if (t == ENUM) 3334 return INT; 3335 if (farg && t == FLOAT) 3336 return DOUBLE; 3337 return t; 3338 } 3339 3340 /* 3341 * Performs the "integer promotions" (C99 6.3.1.1p2), which convert small 3342 * integer types to either int or unsigned int. 3343 * 3344 * If allow_c90 is unset or the operand is a function argument with no type 3345 * information (no prototype or variable # of args), converts float to double. 3346 */ 3347 tnode_t * 3348 promote(op_t op, bool farg, tnode_t *tn) 3349 { 3350 3351 const type_t *otp = tn->tn_type; 3352 tspec_t ot = otp->t_tspec; 3353 if (!is_arithmetic(ot)) 3354 return tn; 3355 3356 tspec_t nt = allow_c90 ? promote_c90(tn, ot, farg) : promote_trad(ot); 3357 if (nt == ot) 3358 return tn; 3359 3360 type_t *ntp = expr_dup_type(gettyp(nt)); 3361 ntp->t_tspec = nt; 3362 ntp->t_is_enum = otp->t_is_enum; 3363 if (ntp->t_is_enum) 3364 ntp->u.enumer = otp->u.enumer; 3365 ntp->t_bitfield = otp->t_bitfield; 3366 if (ntp->t_bitfield) { 3367 ntp->t_bit_field_width = otp->t_bit_field_width; 3368 ntp->t_bit_field_offset = otp->t_bit_field_offset; 3369 } 3370 if (ntp->t_bitfield && is_uinteger(ot) && !is_uinteger(nt)) 3371 ntp->t_bit_field_width++; 3372 return convert(op, 0, ntp, tn); 3373 } 3374 3375 static void 3376 check_lossy_floating_to_integer_conversion( 3377 op_t op, int arg, const type_t *tp, const tnode_t *tn) 3378 { 3379 long double x = tn->u.value.u.floating; 3380 integer_constraints ic = ic_any(tp); 3381 if (is_uinteger(tp->t_tspec) 3382 ? x >= ic.umin && x <= ic.umax && x == (uint64_t)x 3383 : x >= ic.smin && x <= ic.smax && x == (int64_t)x) 3384 return; 3385 if (op == FARG) 3386 /* lossy conversion of %Lg to '%s', arg #%d */ 3387 warning(380, x, type_name(tp), arg); 3388 else 3389 /* lossy conversion of %Lg to '%s' */ 3390 warning(381, x, type_name(tp)); 3391 } 3392 3393 static void 3394 convert_integer_from_floating( 3395 op_t op, int arg, const type_t *tp, const tnode_t *tn) 3396 { 3397 3398 if (op == CVT) 3399 /* cast from floating point '%s' to integer '%s' */ 3400 query_message(2, type_name(tn->tn_type), type_name(tp)); 3401 else 3402 /* implicit conversion from floating point '%s' to ... */ 3403 query_message(1, type_name(tn->tn_type), type_name(tp)); 3404 if (tn->tn_op == CON) 3405 check_lossy_floating_to_integer_conversion(op, arg, tp, tn); 3406 } 3407 3408 static bool 3409 should_warn_about_prototype_conversion(tspec_t nt, 3410 tspec_t ot, const tnode_t *ptn) 3411 { 3412 3413 if (nt == ot) 3414 return false; 3415 3416 if (nt == ENUM && ot == INT) 3417 return false; 3418 3419 if (is_floating(nt) != is_floating(ot) || 3420 portable_rank_cmp(nt, ot) != 0) { 3421 /* representation and/or width change */ 3422 if (!is_integer(ot)) 3423 return true; 3424 /* 3425 * XXX: Investigate whether this rule makes sense; see 3426 * tests/usr.bin/xlint/lint1/platform_long.c. 3427 */ 3428 return portable_rank_cmp(ot, INT) > 0; 3429 } 3430 3431 if (!hflag) 3432 return false; 3433 3434 /* 3435 * If the types differ only in sign and the argument has the same 3436 * representation in both types, print no warning. 3437 */ 3438 if (ptn->tn_op == CON && is_integer(nt) && 3439 signed_type(nt) == signed_type(ot) && 3440 !msb(ptn->u.value.u.integer, ot)) 3441 return false; 3442 3443 return true; 3444 } 3445 3446 /* 3447 * Warn if a prototype causes a type conversion that is different from what 3448 * would happen to the same argument in the absence of a prototype. This 3449 * check is intended for code that needs to stay compatible with pre-C90 C. 3450 * 3451 * Errors/warnings about illegal type combinations are already printed 3452 * in check_assign_types_compatible(). 3453 */ 3454 static void 3455 check_prototype_conversion(int arg, tspec_t nt, tspec_t ot, type_t *tp, 3456 tnode_t *tn) 3457 { 3458 3459 if (!is_arithmetic(nt) || !is_arithmetic(ot)) 3460 return; 3461 3462 /* 3463 * If the type of the formal parameter is char/short, a warning would 3464 * be useless, because functions declared the old style can't expect 3465 * char/short arguments. 3466 */ 3467 if (nt == CHAR || nt == SCHAR || nt == UCHAR || 3468 nt == SHORT || nt == USHORT) 3469 return; 3470 3471 tnode_t *ptn = promote(NOOP, true, tn); 3472 ot = ptn->tn_type->t_tspec; 3473 3474 if (should_warn_about_prototype_conversion(nt, ot, ptn)) { 3475 /* argument %d is converted from '%s' to '%s' ... */ 3476 warning(259, arg, type_name(tn->tn_type), type_name(tp)); 3477 } 3478 } 3479 3480 /* 3481 * When converting a large integer type to a small integer type, in some 3482 * cases the value of the actual expression is further restricted than the 3483 * type bounds, such as in (expr & 0xFF) or (expr % 100) or (expr >> 24). 3484 */ 3485 static bool 3486 can_represent(const type_t *tp, const tnode_t *tn) 3487 { 3488 uint64_t nmask = value_bits(width_in_bits(tp)); 3489 if (!is_uinteger(tp->t_tspec)) 3490 nmask >>= 1; 3491 3492 integer_constraints c = ic_expr(tn); 3493 if ((~c.bclr & ~nmask) == 0) 3494 return true; 3495 3496 integer_constraints tpc = ic_any(tp); 3497 if (is_uinteger(tp->t_tspec) 3498 ? tpc.umin <= c.umin && tpc.umax >= c.umax 3499 : tpc.smin <= c.smin && tpc.smax >= c.smax) 3500 return true; 3501 3502 debug_enter(); 3503 debug_step("type '%s' cannot represent:", type_name(tp)); 3504 debug_node(tn); 3505 debug_leave(); 3506 return false; 3507 } 3508 3509 static bool 3510 should_warn_about_integer_conversion(const type_t *ntp, tspec_t nt, 3511 const tnode_t *otn, tspec_t ot) 3512 { 3513 3514 // XXX: The portable_rank_cmp aims at portable mode, independent of the 3515 // current platform, while can_represent acts on the actual type sizes 3516 // from the current platform. This mix is inconsistent, but anything 3517 // else would make the exact conditions too complicated to grasp. 3518 if (aflag > 0 && portable_rank_cmp(nt, ot) < 0) { 3519 if (ot == LONG || ot == ULONG 3520 || ot == LLONG || ot == ULLONG 3521 #ifdef INT128_SIZE 3522 || ot == INT128 || ot == UINT128 3523 #endif 3524 || aflag > 1) 3525 return !can_represent(ntp, otn); 3526 } 3527 return false; 3528 } 3529 3530 static void 3531 convert_integer_from_integer(op_t op, int arg, tspec_t nt, tspec_t ot, 3532 type_t *tp, tnode_t *tn) 3533 { 3534 3535 if (tn->tn_op == CON) 3536 return; 3537 3538 if (op == CVT) 3539 return; 3540 3541 if (Pflag && pflag && aflag > 0 && 3542 portable_rank_cmp(nt, ot) > 0 && 3543 is_uinteger(nt) != is_uinteger(ot)) { 3544 if (op == FARG) 3545 /* conversion to '%s' may sign-extend ... */ 3546 warning(297, type_name(tp), arg); 3547 else 3548 /* conversion to '%s' may sign-extend ... */ 3549 warning(131, type_name(tp)); 3550 } 3551 3552 if (Pflag && portable_rank_cmp(nt, ot) > 0 && 3553 (tn->tn_op == PLUS || tn->tn_op == MINUS || tn->tn_op == MULT || 3554 tn->tn_op == SHL)) { 3555 /* suggest cast from '%s' to '%s' on op '%s' to ... */ 3556 warning(324, type_name(gettyp(ot)), type_name(tp), 3557 op_name(tn->tn_op)); 3558 } 3559 3560 if (should_warn_about_integer_conversion(tp, nt, tn, ot)) { 3561 if (op == FARG) { 3562 /* conversion from '%s' to '%s' may lose ... */ 3563 warning(298, 3564 type_name(tn->tn_type), type_name(tp), arg); 3565 } else { 3566 /* conversion from '%s' to '%s' may lose accuracy */ 3567 warning(132, 3568 type_name(tn->tn_type), type_name(tp)); 3569 } 3570 } 3571 3572 if (is_uinteger(nt) != is_uinteger(ot)) 3573 /* implicit conversion changes sign from '%s' to '%s' */ 3574 query_message(3, type_name(tn->tn_type), type_name(tp)); 3575 } 3576 3577 static void 3578 convert_integer_from_pointer(op_t op, tspec_t nt, type_t *tp, tnode_t *tn) 3579 { 3580 3581 if (tn->tn_op == CON) 3582 return; 3583 if (op != CVT) 3584 return; /* We already got an error. */ 3585 if (portable_rank_cmp(nt, PTR) >= 0) 3586 return; 3587 3588 if (pflag && size_in_bits(nt) >= size_in_bits(PTR)) { 3589 /* conversion of pointer to '%s' may lose bits */ 3590 warning(134, type_name(tp)); 3591 } else { 3592 /* conversion of pointer to '%s' loses bits */ 3593 warning(133, type_name(tp)); 3594 } 3595 } 3596 3597 static bool 3598 struct_starts_with(const type_t *struct_tp, const type_t *member_tp) 3599 { 3600 3601 return struct_tp->u.sou->sou_first_member != NULL && 3602 types_compatible(struct_tp->u.sou->sou_first_member->s_type, 3603 member_tp, true, false, NULL); 3604 } 3605 3606 static bool 3607 is_byte_array(const type_t *tp) 3608 { 3609 3610 return tp->t_tspec == ARRAY && 3611 (tp->t_subt->t_tspec == CHAR || tp->t_subt->t_tspec == UCHAR); 3612 } 3613 3614 static bool 3615 union_contains(const type_t *utp, const type_t *mtp) 3616 { 3617 for (const sym_t *mem = utp->u.sou->sou_first_member; 3618 mem != NULL; mem = mem->s_next) { 3619 if (types_compatible(mem->s_type, mtp, true, false, NULL)) 3620 return true; 3621 } 3622 return false; 3623 } 3624 3625 static bool 3626 should_warn_about_pointer_cast(const type_t *nstp, tspec_t nst, 3627 const type_t *ostp, tspec_t ost) 3628 { 3629 3630 while (nst == ARRAY) 3631 nstp = nstp->t_subt, nst = nstp->t_tspec; 3632 while (ost == ARRAY) 3633 ostp = ostp->t_subt, ost = ostp->t_tspec; 3634 3635 if (nst == STRUCT && ost == STRUCT && 3636 (struct_starts_with(nstp, ostp) || 3637 struct_starts_with(ostp, nstp))) 3638 return false; 3639 3640 if (is_incomplete(nstp) || is_incomplete(ostp)) 3641 return false; 3642 3643 if (nst == CHAR || nst == UCHAR) 3644 return false; /* for the sake of traditional C code */ 3645 if (ost == CHAR || ost == UCHAR) 3646 return false; /* for the sake of traditional C code */ 3647 3648 /* Allow cast between pointers to sockaddr variants. */ 3649 if (nst == STRUCT && ost == STRUCT) { 3650 const sym_t *nmem = nstp->u.sou->sou_first_member; 3651 const sym_t *omem = ostp->u.sou->sou_first_member; 3652 while (nmem != NULL && omem != NULL && 3653 types_compatible(nmem->s_type, omem->s_type, 3654 true, false, NULL)) 3655 nmem = nmem->s_next, omem = omem->s_next; 3656 if (nmem != NULL && is_byte_array(nmem->s_type)) 3657 return false; 3658 if (omem != NULL && is_byte_array(omem->s_type)) 3659 return false; 3660 if (nmem == NULL && omem == NULL) 3661 return false; 3662 } 3663 3664 if (nst == UNION || ost == UNION) { 3665 const type_t *union_tp = nst == UNION ? nstp : ostp; 3666 const type_t *other_tp = nst == UNION ? ostp : nstp; 3667 if (union_contains(union_tp, other_tp)) 3668 return false; 3669 } 3670 3671 if (is_struct_or_union(nst) && is_struct_or_union(ost)) 3672 return nstp->u.sou != ostp->u.sou; 3673 3674 enum rank_kind rk1 = type_properties(nst)->tt_rank_kind; 3675 enum rank_kind rk2 = type_properties(ost)->tt_rank_kind; 3676 if (rk1 != rk2 || rk1 == RK_NONE) 3677 return true; 3678 3679 return portable_rank_cmp(nst, ost) != 0; 3680 } 3681 3682 static void 3683 convert_pointer_from_pointer(type_t *ntp, tnode_t *tn) 3684 { 3685 const type_t *nstp = ntp->t_subt; 3686 const type_t *otp = tn->tn_type; 3687 const type_t *ostp = otp->t_subt; 3688 tspec_t nst = nstp->t_tspec; 3689 tspec_t ost = ostp->t_tspec; 3690 3691 if (nst == VOID || ost == VOID) { 3692 /* TODO: C99 behaves like C90 here. */ 3693 if (!allow_trad && !allow_c99 && (nst == FUNC || ost == FUNC)) { 3694 const char *nts, *ots; 3695 /* null pointers are already handled in convert() */ 3696 *(nst == FUNC ? &nts : &ots) = "function pointer"; 3697 *(nst == VOID ? &nts : &ots) = "'void *'"; 3698 /* conversion of %s to %s requires a cast */ 3699 warning(303, ots, nts); 3700 } 3701 return; 3702 } 3703 if (nst == FUNC && ost == FUNC) 3704 return; 3705 if (nst == FUNC || ost == FUNC) { 3706 /* converting '%s' to '%s' is questionable */ 3707 warning(229, type_name(otp), type_name(ntp)); 3708 return; 3709 } 3710 3711 if (hflag && alignment(nstp) > alignment(ostp) && 3712 ost != CHAR && ost != UCHAR && 3713 !is_incomplete(ostp) && 3714 !(nst == UNION && union_contains(nstp, ostp))) { 3715 /* converting '%s' to '%s' increases alignment ... */ 3716 warning(135, type_name(otp), type_name(ntp), 3717 alignment(ostp), alignment(nstp)); 3718 } 3719 3720 if (cflag && should_warn_about_pointer_cast(nstp, nst, ostp, ost)) { 3721 /* pointer cast from '%s' to unrelated '%s' */ 3722 warning(247, type_name(ostp), type_name(nstp)); 3723 } 3724 } 3725 3726 /* 3727 * Insert a conversion operator, which converts the type of the node 3728 * to another given type. 3729 * 3730 * Possible values for 'op': 3731 * CVT a cast-expression 3732 * binary integer promotion for one of the operands, or a usual 3733 * arithmetic conversion 3734 * binary plain or compound assignments to bit-fields 3735 * FARG 'arg' is the number of the parameter (used for warnings) 3736 * NOOP several other implicit conversions 3737 * ... 3738 */ 3739 tnode_t * 3740 convert(op_t op, int arg, type_t *tp, tnode_t *tn) 3741 { 3742 tspec_t nt = tp->t_tspec; 3743 tspec_t ot = tn->tn_type->t_tspec; 3744 3745 if (allow_trad && allow_c90 && op == FARG) 3746 check_prototype_conversion(arg, nt, ot, tp, tn); 3747 3748 if (nt == BOOL) { 3749 /* No further checks. */ 3750 3751 } else if (is_integer(nt)) { 3752 if (ot == BOOL) { 3753 /* No further checks. */ 3754 } else if (is_integer(ot)) 3755 convert_integer_from_integer(op, arg, nt, ot, tp, tn); 3756 else if (is_floating(ot)) 3757 convert_integer_from_floating(op, arg, tp, tn); 3758 else if (ot == PTR) 3759 convert_integer_from_pointer(op, nt, tp, tn); 3760 3761 } else if (is_floating(nt)) { 3762 if (is_integer(ot) && op != CVT) { 3763 /* implicit conversion from integer '%s' to ... */ 3764 query_message(19, 3765 type_name(tn->tn_type), type_name(tp)); 3766 } 3767 3768 } else if (nt == PTR) { 3769 if (is_null_pointer(tn)) { 3770 /* a null pointer may be assigned to any pointer. */ 3771 } else if (ot == PTR && op == CVT) 3772 convert_pointer_from_pointer(tp, tn); 3773 } 3774 3775 tnode_t *ntn = expr_alloc_tnode(); 3776 ntn->tn_op = CVT; 3777 ntn->tn_type = tp; 3778 ntn->tn_cast = op == CVT; 3779 ntn->tn_sys |= tn->tn_sys; 3780 ntn->u.ops.right = NULL; 3781 if (tn->tn_op != CON || nt == VOID) { 3782 ntn->u.ops.left = tn; 3783 } else { 3784 ntn->tn_op = CON; 3785 convert_constant(op, arg, ntn->tn_type, &ntn->u.value, 3786 &tn->u.value); 3787 } 3788 3789 return ntn; 3790 } 3791 3792 static void 3793 convert_constant_from_floating(op_t op, int arg, const type_t *ntp, 3794 tspec_t nt, val_t *nv, val_t *ov) 3795 { 3796 long double max = 0.0, min = 0.0; 3797 3798 switch (nt) { 3799 case CHAR: 3800 max = TARG_CHAR_MAX; min = TARG_CHAR_MIN; break; 3801 case UCHAR: 3802 max = TARG_UCHAR_MAX; min = 0; break; 3803 case SCHAR: 3804 max = TARG_SCHAR_MAX; min = TARG_SCHAR_MIN; break; 3805 case SHORT: 3806 max = TARG_SHRT_MAX; min = TARG_SHRT_MIN; break; 3807 case USHORT: 3808 max = TARG_USHRT_MAX; min = 0; break; 3809 case ENUM: 3810 case INT: 3811 max = TARG_INT_MAX; min = TARG_INT_MIN; break; 3812 case UINT: 3813 max = TARG_UINT_MAX; min = 0; break; 3814 case LONG: 3815 max = TARG_LONG_MAX; min = TARG_LONG_MIN; break; 3816 case ULONG: 3817 max = TARG_ULONG_MAX; min = 0; break; 3818 case LLONG: 3819 max = LLONG_MAX; min = LLONG_MIN; break; 3820 case ULLONG: 3821 max = ULLONG_MAX; min = 0; break; 3822 case FLOAT: 3823 case FCOMPLEX: 3824 max = FLT_MAX; min = -FLT_MAX; break; 3825 case DOUBLE: 3826 case DCOMPLEX: 3827 max = DBL_MAX; min = -DBL_MAX; break; 3828 case LDOUBLE: 3829 case LCOMPLEX: 3830 /* LINTED 248; see floating_error_value. */ 3831 max = LDBL_MAX; min = -max; break; 3832 default: 3833 lint_assert(/*CONSTCOND*/false); 3834 } 3835 if (ov->u.floating > max || ov->u.floating < min) { 3836 lint_assert(nt != LDOUBLE); 3837 const char *ot_name = type_name(gettyp(ov->v_tspec)); 3838 const char *nt_name = type_name(ntp); 3839 if (is_integer(nt)) 3840 goto after_warning; 3841 if (op == FARG) 3842 /* conversion of '%s' to '%s' is out of range, ... */ 3843 warning(295, ot_name, nt_name, arg); 3844 else 3845 /* conversion of '%s' to '%s' is out of range */ 3846 warning(119, ot_name, nt_name); 3847 after_warning: 3848 ov->u.floating = ov->u.floating > 0 ? max : min; 3849 } 3850 3851 if (nt == FLOAT || nt == FCOMPLEX) 3852 nv->u.floating = (float)ov->u.floating; 3853 else if (nt == DOUBLE || nt == DCOMPLEX) 3854 nv->u.floating = (double)ov->u.floating; 3855 else if (nt == LDOUBLE || nt == LCOMPLEX) 3856 nv->u.floating = ov->u.floating; 3857 else 3858 nv->u.integer = (int64_t)ov->u.floating; 3859 } 3860 3861 static bool 3862 convert_constant_to_floating(tspec_t nt, val_t *nv, 3863 tspec_t ot, const val_t *v) 3864 { 3865 if (nt == FLOAT) { 3866 nv->u.floating = (ot == PTR || is_uinteger(ot)) ? 3867 (float)(uint64_t)v->u.integer : (float)v->u.integer; 3868 } else if (nt == DOUBLE) { 3869 nv->u.floating = (ot == PTR || is_uinteger(ot)) ? 3870 (double)(uint64_t)v->u.integer : (double)v->u.integer; 3871 } else if (nt == LDOUBLE) { 3872 nv->u.floating = (ot == PTR || is_uinteger(ot)) 3873 ? (long double)(uint64_t)v->u.integer 3874 : (long double)v->u.integer; 3875 } else 3876 return false; 3877 return true; 3878 } 3879 3880 /* 3881 * Print a warning if bits which were set are lost due to the conversion. 3882 * This can happen with operator ORASS only. 3883 */ 3884 static void 3885 convert_constant_check_range_bitor(size_t nsz, size_t osz, const val_t *v, 3886 uint64_t xmask, op_t op) 3887 { 3888 if (nsz < osz && (v->u.integer & xmask) != 0) 3889 /* constant truncated by conversion, op '%s' */ 3890 warning(306, op_name(op)); 3891 } 3892 3893 static void 3894 convert_constant_check_range_bitand(size_t nsz, size_t osz, 3895 uint64_t xmask, const val_t *nv, 3896 tspec_t ot, const val_t *v, 3897 const type_t *tp, op_t op) 3898 { 3899 if (nsz > osz && 3900 (nv->u.integer & bit((unsigned int)(osz - 1))) != 0 && 3901 (nv->u.integer & xmask) != xmask) { 3902 /* extra bits set to 0 in conversion of '%s' to '%s', ... */ 3903 warning(309, type_name(gettyp(ot)), 3904 type_name(tp), op_name(op)); 3905 } else if (nsz < osz && 3906 (v->u.integer & xmask) != xmask && 3907 (v->u.integer & xmask) != 0) 3908 /* constant truncated by conversion, op '%s' */ 3909 warning(306, op_name(op)); 3910 } 3911 3912 static void 3913 convert_constant_check_range_signed(op_t op, int arg, 3914 const type_t *ntp, int64_t ov) 3915 { 3916 if (op == ASSIGN) 3917 /* assignment of negative constant %lld to unsigned ... */ 3918 warning(164, (long long)ov, type_name(ntp)); 3919 else if (op == INIT) 3920 /* initialization of unsigned type '%s' with negative ... */ 3921 warning(221, type_name(ntp), (long long)ov); 3922 else if (op == FARG) 3923 /* conversion of negative constant %lld to unsigned ... */ 3924 warning(296, (long long)ov, type_name(ntp), arg); 3925 else if (modtab[op].m_comparison) { 3926 /* handled by check_integer_comparison() */ 3927 } else 3928 /* conversion of negative constant %lld to unsigned ... */ 3929 warning(222, (long long)ov, type_name(ntp)); 3930 } 3931 3932 /* 3933 * Loss of significant bit(s). All truncated bits of unsigned types or all 3934 * truncated bits plus the msb of the target for signed types are considered 3935 * to be significant bits. Loss of significant bits means that at least one 3936 * of the bits was set in an unsigned type or that at least one but not all 3937 * of the bits was set in a signed type. Loss of significant bits means that 3938 * it is not possible, also not with necessary casts, to convert back to the 3939 * original type. An example for a necessary cast is: 3940 * char c; int i; c = 128; 3941 * i = c; ** yields -128 ** 3942 * i = (unsigned char)c; ** yields 128 ** 3943 */ 3944 static void 3945 warn_constant_check_range_truncated(op_t op, int arg, const type_t *tp, 3946 tspec_t ot) 3947 { 3948 if (op == ASSIGN && tp->t_bitfield) 3949 /* precision lost in bit-field assignment */ 3950 warning(166); 3951 else if (op == ASSIGN) 3952 /* constant truncated by assignment */ 3953 warning(165); 3954 else if (op == INIT && tp->t_bitfield) 3955 /* bit-field initializer does not fit */ 3956 warning(180); 3957 else if (op == INIT) 3958 /* initializer does not fit */ 3959 warning(178); 3960 else if (op == CASE) 3961 /* case label affected by conversion */ 3962 warning(196); 3963 else if (op == FARG) 3964 /* conversion of '%s' to '%s' is out of range, arg #%d */ 3965 warning(295, type_name(gettyp(ot)), type_name(tp), arg); 3966 else 3967 /* conversion of '%s' to '%s' is out of range */ 3968 warning(119, type_name(gettyp(ot)), type_name(tp)); 3969 } 3970 3971 static void 3972 warn_constant_check_range_loss(op_t op, int arg, const type_t *tp, 3973 tspec_t ot) 3974 { 3975 if (op == ASSIGN && tp->t_bitfield) 3976 /* precision lost in bit-field assignment */ 3977 warning(166); 3978 else if (op == INIT && tp->t_bitfield) 3979 /* bit-field initializer out of range */ 3980 warning(11); 3981 else if (op == CASE) 3982 /* case label affected by conversion */ 3983 warning(196); 3984 else if (op == FARG) 3985 /* conversion of '%s' to '%s' is out of range, arg #%d */ 3986 warning(295, type_name(gettyp(ot)), type_name(tp), arg); 3987 else 3988 /* conversion of '%s' to '%s' is out of range */ 3989 warning(119, type_name(gettyp(ot)), type_name(tp)); 3990 } 3991 3992 static void 3993 convert_constant_check_range(tspec_t ot, const type_t *tp, tspec_t nt, 3994 op_t op, int arg, const val_t *v, val_t *nv) 3995 { 3996 unsigned int obitsz, nbitsz; 3997 uint64_t xmask, xmsk1; 3998 3999 obitsz = size_in_bits(ot); 4000 nbitsz = tp->t_bitfield ? tp->t_bit_field_width : size_in_bits(nt); 4001 xmask = value_bits(nbitsz) ^ value_bits(obitsz); 4002 xmsk1 = value_bits(nbitsz) ^ value_bits(obitsz - 1); 4003 if (op == ORASS || op == BITOR || op == BITXOR) { 4004 convert_constant_check_range_bitor( 4005 nbitsz, obitsz, v, xmask, op); 4006 } else if (op == ANDASS || op == BITAND) { 4007 convert_constant_check_range_bitand( 4008 nbitsz, obitsz, xmask, nv, ot, v, tp, op); 4009 } else if (nt != PTR && is_uinteger(nt) && 4010 ot != PTR && !is_uinteger(ot) && 4011 v->u.integer < 0) 4012 convert_constant_check_range_signed(op, arg, 4013 tp, v->u.integer); 4014 else if (nv->u.integer != v->u.integer && nbitsz <= obitsz && 4015 (v->u.integer & xmask) != 0 && 4016 (is_uinteger(ot) || (v->u.integer & xmsk1) != xmsk1)) 4017 warn_constant_check_range_truncated(op, arg, tp, ot); 4018 else if (nv->u.integer != v->u.integer) 4019 warn_constant_check_range_loss(op, arg, tp, ot); 4020 } 4021 4022 /* Converts a typed constant to a constant of another type. */ 4023 void 4024 convert_constant(op_t op, int arg, const type_t *ntp, val_t *nv, val_t *ov) 4025 { 4026 /* 4027 * TODO: make 'ov' const; the name of this function does not suggest 4028 * that it modifies 'ov'. 4029 */ 4030 tspec_t ot = ov->v_tspec; 4031 tspec_t nt = nv->v_tspec = ntp->t_tspec; 4032 bool range_check = false; 4033 4034 if (nt == BOOL) { /* C99 6.3.1.2 */ 4035 nv->v_unsigned_since_c90 = false; 4036 nv->u.integer = is_nonzero_val(ov) ? 1 : 0; 4037 return; 4038 } 4039 4040 if (ot == FLOAT || ot == DOUBLE || ot == LDOUBLE) 4041 convert_constant_from_floating(op, arg, ntp, nt, nv, ov); 4042 else if (!convert_constant_to_floating(nt, nv, ot, ov)) { 4043 range_check = true; /* Check for lost precision. */ 4044 nv->u.integer = ov->u.integer; 4045 } 4046 4047 if (allow_trad && allow_c90 && ov->v_unsigned_since_c90 && 4048 (is_floating(nt) || ( 4049 (is_integer(nt) && !is_uinteger(nt) && 4050 portable_rank_cmp(nt, ot) > 0)))) { 4051 /* C90 treats constant as unsigned */ 4052 warning(157); 4053 ov->v_unsigned_since_c90 = false; 4054 } 4055 4056 if (is_integer(nt)) { 4057 unsigned int size = ntp->t_bitfield 4058 ? ntp->t_bit_field_width : size_in_bits(nt); 4059 nv->u.integer = convert_integer(nv->u.integer, nt, size); 4060 } 4061 4062 if (range_check && op != CVT) 4063 convert_constant_check_range(ot, ntp, nt, op, arg, ov, nv); 4064 } 4065 4066 tnode_t * 4067 build_sizeof(const type_t *tp) 4068 { 4069 unsigned int size_in_bytes = type_size_in_bits(tp) / CHAR_SIZE; 4070 tnode_t *tn = build_integer_constant(SIZEOF_TSPEC, size_in_bytes); 4071 tn->tn_system_dependent = true; 4072 debug_step("build_sizeof '%s' = %u", type_name(tp), size_in_bytes); 4073 return tn; 4074 } 4075 4076 tnode_t * 4077 build_offsetof(const type_t *tp, designation dn) 4078 { 4079 unsigned int offset_in_bits = 0; 4080 4081 if (!is_struct_or_union(tp->t_tspec)) { 4082 /* unacceptable operand of '%s' */ 4083 error(111, "offsetof"); 4084 goto proceed; 4085 } 4086 for (size_t i = 0; i < dn.dn_len; i++) { 4087 const designator *dr = dn.dn_items + i; 4088 if (dr->dr_kind == DK_SUBSCRIPT) { 4089 if (tp->t_tspec != ARRAY) 4090 goto proceed; /* silent error */ 4091 tp = tp->t_subt; 4092 offset_in_bits += (unsigned) dr->dr_subscript 4093 * type_size_in_bits(tp); 4094 } else { 4095 if (!is_struct_or_union(tp->t_tspec)) 4096 goto proceed; /* silent error */ 4097 const char *name = dr->dr_member->s_name; 4098 sym_t *mem = find_member(tp->u.sou, name); 4099 if (mem == NULL) { 4100 /* type '%s' does not have member '%s' */ 4101 error(101, name, type_name(tp)); 4102 goto proceed; 4103 } 4104 tp = mem->s_type; 4105 offset_in_bits += mem->u.s_member.sm_offset_in_bits; 4106 } 4107 } 4108 free(dn.dn_items); 4109 4110 proceed:; 4111 unsigned int offset_in_bytes = offset_in_bits / CHAR_SIZE; 4112 tnode_t *tn = build_integer_constant(SIZEOF_TSPEC, offset_in_bytes); 4113 tn->tn_system_dependent = true; 4114 return tn; 4115 } 4116 4117 unsigned int 4118 type_size_in_bits(const type_t *tp) 4119 { 4120 4121 unsigned int elem = 1; 4122 bool flex = false; 4123 lint_assert(tp != NULL); 4124 while (tp->t_tspec == ARRAY) { 4125 flex = true; /* allow c99 flex arrays [] [0] */ 4126 elem *= tp->u.dimension; 4127 tp = tp->t_subt; 4128 } 4129 if (elem == 0 && !flex) { 4130 /* cannot take size/alignment of incomplete type */ 4131 error(143); 4132 elem = 1; 4133 } 4134 4135 unsigned int elsz; 4136 switch (tp->t_tspec) { 4137 case VOID: 4138 /* cannot take size/alignment of void */ 4139 error(146); 4140 elsz = 1; 4141 break; 4142 case FUNC: 4143 /* cannot take size/alignment of function type '%s' */ 4144 error(144, type_name(tp)); 4145 elsz = 1; 4146 break; 4147 case STRUCT: 4148 case UNION: 4149 if (is_incomplete(tp)) { 4150 /* cannot take size/alignment of incomplete type */ 4151 error(143); 4152 elsz = 1; 4153 } else 4154 elsz = tp->u.sou->sou_size_in_bits; 4155 break; 4156 case ENUM: 4157 if (is_incomplete(tp)) { 4158 /* cannot take size/alignment of incomplete type */ 4159 warning(143); 4160 } 4161 /* FALLTHROUGH */ 4162 default: 4163 if (tp->t_bitfield) 4164 /* cannot take size/alignment of bit-field */ 4165 error(145); 4166 elsz = size_in_bits(tp->t_tspec); 4167 lint_assert(elsz > 0); 4168 break; 4169 } 4170 4171 return elem * elsz; 4172 } 4173 4174 /* C11 6.5.3.4, GCC */ 4175 tnode_t * 4176 build_alignof(const type_t *tp) 4177 { 4178 if (tp->t_tspec == FUNC) { 4179 /* cannot take size/alignment of function type '%s' */ 4180 error(144, type_name(tp)); 4181 return NULL; 4182 } 4183 if (tp->t_tspec == VOID) { 4184 /* cannot take size/alignment of void */ 4185 error(146); 4186 return NULL; 4187 } 4188 if (is_incomplete(tp)) { 4189 /* cannot take size/alignment of incomplete type */ 4190 error(143); 4191 return NULL; 4192 } 4193 if (tp->t_bitfield) { 4194 /* cannot take size/alignment of bit-field */ 4195 error(145); 4196 return NULL; 4197 } 4198 return build_integer_constant(SIZEOF_TSPEC, (int64_t)alignment(tp)); 4199 } 4200 4201 static tnode_t * 4202 cast_to_union(tnode_t *otn, bool sys, type_t *ntp) 4203 { 4204 4205 if (!allow_gcc) { 4206 /* union cast is a GCC extension */ 4207 error(328); 4208 return NULL; 4209 } 4210 4211 for (const sym_t *m = ntp->u.sou->sou_first_member; 4212 m != NULL; m = m->s_next) { 4213 if (types_compatible(m->s_type, otn->tn_type, 4214 false, false, NULL)) { 4215 tnode_t *ntn = build_op(CVT, sys, ntp, otn, NULL); 4216 ntn->tn_cast = true; 4217 return ntn; 4218 } 4219 } 4220 4221 /* type '%s' is not a member of '%s' */ 4222 error(329, type_name(otn->tn_type), type_name(ntp)); 4223 return NULL; 4224 } 4225 4226 // In GCC mode, allow 'nullptr + offset' as a constant expression. 4227 static tnode_t * 4228 null_pointer_offset(tnode_t *tn) 4229 { 4230 uint64_t off = 0; 4231 const tnode_t *n = tn; 4232 while ((n->tn_op == PLUS || n->tn_op == MINUS) 4233 && is_integer(n->u.ops.right->tn_type->t_tspec)) { 4234 off += (uint64_t)n->u.ops.right->u.value.u.integer; 4235 n = n->u.ops.left; 4236 } 4237 if (n->tn_type->t_tspec == PTR 4238 && n->tn_op == ADDR 4239 && n->u.ops.left->tn_op == INDIR 4240 && n->u.ops.left->u.ops.left->tn_op == CON 4241 && n->u.ops.left->u.ops.left->tn_type->t_tspec == PTR) { 4242 off += (uint64_t)n->u.ops.left->u.ops.left->u.value.u.integer; 4243 return build_integer_constant(SIZEOF_TSPEC, (int64_t)off); 4244 } 4245 return tn; 4246 } 4247 4248 tnode_t * 4249 cast(tnode_t *tn, bool sys, type_t *tp) 4250 { 4251 4252 if (tn == NULL) 4253 return NULL; 4254 4255 tn = cconv(tn); 4256 4257 lint_assert(tp != NULL); 4258 tspec_t nt = tp->t_tspec; 4259 tspec_t ot = tn->tn_type->t_tspec; 4260 4261 if (nt == VOID) { 4262 /* 4263 * C90 6.3.4, C99 6.5.4p2 and C11 6.5.4p2 allow any type to be 4264 * cast to void. The only other allowed casts are from a 4265 * scalar type to a scalar type. 4266 */ 4267 } else if (nt == UNION) 4268 return cast_to_union(tn, sys, tp); 4269 else if (nt == STRUCT || nt == ARRAY || nt == FUNC) { 4270 /* Casting to a struct is an undocumented GCC extension. */ 4271 if (!(allow_gcc && nt == STRUCT)) 4272 goto invalid_cast; 4273 } else if (is_struct_or_union(ot)) 4274 goto invalid_cast; 4275 else if (ot == VOID) { 4276 /* improper cast of void expression */ 4277 error(148); 4278 return NULL; 4279 } else if (is_integer(nt) && is_scalar(ot)) { 4280 tn = null_pointer_offset(tn); 4281 } else if (is_floating(nt) && is_arithmetic(ot)) { 4282 /* ok */ 4283 } else if (nt == PTR && is_integer(ot)) { 4284 /* ok */ 4285 } else if (nt == PTR && ot == PTR) { 4286 if (!tp->t_subt->t_const && tn->tn_type->t_subt->t_const) { 4287 if (hflag) 4288 /* cast discards 'const' from type '%s' */ 4289 warning(275, type_name(tn->tn_type)); 4290 } 4291 } else 4292 goto invalid_cast; 4293 4294 if (any_query_enabled 4295 && types_compatible(tp, tn->tn_type, false, false, NULL)) 4296 /* no-op cast from '%s' to '%s' */ 4297 query_message(6, type_name(tn->tn_type), type_name(tp)); 4298 4299 tn = convert(CVT, 0, tp, tn); 4300 tn->tn_cast = true; 4301 tn->tn_sys = sys; 4302 4303 return tn; 4304 4305 invalid_cast: 4306 /* invalid cast from '%s' to '%s' */ 4307 error(147, type_name(tn->tn_type), type_name(tp)); 4308 return NULL; 4309 } 4310 4311 void 4312 add_function_argument(function_call *call, tnode_t *arg) 4313 { 4314 /* 4315 * If there was a serious error in the expression for the argument, 4316 * create a dummy argument so the positions of the remaining arguments 4317 * will not change. 4318 */ 4319 if (arg == NULL) 4320 arg = build_integer_constant(INT, 0); 4321 4322 if (call->args_len >= call->args_cap) { 4323 call->args_cap += 8; 4324 tnode_t **new_args = expr_zero_alloc( 4325 call->args_cap * sizeof(*call->args), "tnode*[]"); 4326 if (call->args_len > 0) 4327 memcpy(new_args, call->args, 4328 call->args_len * sizeof(*call->args)); 4329 call->args = new_args; 4330 } 4331 call->args[call->args_len++] = arg; 4332 } 4333 4334 /* 4335 * Compare the type of an argument with the corresponding type of a 4336 * prototype parameter. If it is a valid combination, but both types 4337 * are not the same, insert a conversion to convert the argument into 4338 * the type of the parameter. 4339 */ 4340 static tnode_t * 4341 check_prototype_argument( 4342 int n, /* pos of arg */ 4343 type_t *tp, /* expected type (from prototype) */ 4344 tnode_t *tn) /* argument */ 4345 { 4346 tnode_t *ln = xcalloc(1, sizeof(*ln)); 4347 ln->tn_type = expr_unqualified_type(tp); 4348 ln->tn_lvalue = true; 4349 if (typeok(FARG, n, ln, tn)) { 4350 bool dowarn; 4351 if (!types_compatible(tp, tn->tn_type, 4352 true, false, (dowarn = false, &dowarn)) || dowarn) 4353 tn = convert(FARG, n, tp, tn); 4354 } 4355 free(ln); 4356 return tn; 4357 } 4358 4359 /* 4360 * Check types of all function arguments and insert conversions, 4361 * if necessary. 4362 */ 4363 static void 4364 check_function_arguments(const function_call *call) 4365 { 4366 type_t *ftp = call->func->tn_type->t_subt; 4367 4368 /* get # of parameters in the prototype */ 4369 int npar = 0; 4370 for (const sym_t *p = ftp->u.params; p != NULL; p = p->s_next) 4371 npar++; 4372 4373 int narg = (int)call->args_len; 4374 4375 const sym_t *param = ftp->u.params; 4376 if (ftp->t_proto && npar != narg && !(ftp->t_vararg && npar < narg)) { 4377 /* argument mismatch: %d %s passed, %d expected */ 4378 error(150, narg, narg != 1 ? "arguments" : "argument", npar); 4379 param = NULL; 4380 } 4381 4382 for (int i = 0; i < narg; i++) { 4383 tnode_t *arg = call->args[i]; 4384 4385 /* some things which are always not allowed */ 4386 tspec_t at = arg->tn_type->t_tspec; 4387 if (at == VOID) { 4388 /* void expressions may not be arguments, arg #%d */ 4389 error(151, i + 1); 4390 return; 4391 } 4392 if (is_struct_or_union(at) && is_incomplete(arg->tn_type)) { 4393 /* argument cannot have unknown size, arg #%d */ 4394 error(152, i + 1); 4395 return; 4396 } 4397 if (is_integer(at) && 4398 arg->tn_type->t_is_enum && 4399 is_incomplete(arg->tn_type)) { 4400 /* argument cannot have unknown size, arg #%d */ 4401 warning(152, i + 1); 4402 } 4403 4404 arg = cconv(arg); 4405 call->args[i] = arg; 4406 4407 arg = param != NULL 4408 ? check_prototype_argument(i + 1, param->s_type, arg) 4409 : promote(NOOP, true, arg); 4410 call->args[i] = arg; 4411 4412 if (param != NULL) 4413 param = param->s_next; 4414 } 4415 } 4416 4417 tnode_t * 4418 build_function_call(tnode_t *func, bool sys, function_call *call) 4419 { 4420 4421 if (func == NULL) 4422 return NULL; 4423 4424 call->func = func; 4425 check_ctype_function_call(call); 4426 4427 func = cconv(func); 4428 call->func = func; 4429 4430 if (func->tn_type->t_tspec != PTR || 4431 func->tn_type->t_subt->t_tspec != FUNC) { 4432 /* cannot call '%s', must be a function */ 4433 error(149, type_name(func->tn_type)); 4434 return NULL; 4435 } 4436 4437 check_function_arguments(call); 4438 4439 tnode_t *ntn = expr_alloc_tnode(); 4440 ntn->tn_op = CALL; 4441 ntn->tn_type = func->tn_type->t_subt->t_subt; 4442 ntn->tn_sys = sys; 4443 ntn->u.call = call; 4444 return ntn; 4445 } 4446 4447 /* 4448 * Return the value of an integral constant expression. 4449 * If the expression is not constant or its type is not an integer 4450 * type, an error message is printed. 4451 */ 4452 val_t * 4453 integer_constant(tnode_t *tn, bool required) 4454 { 4455 4456 if (tn != NULL) 4457 tn = cconv(tn); 4458 if (tn != NULL) 4459 tn = promote(NOOP, false, tn); 4460 4461 val_t *v = xcalloc(1, sizeof(*v)); 4462 4463 if (tn == NULL) { 4464 lint_assert(seen_error); 4465 debug_step("constant node is null; returning 1 instead"); 4466 v->v_tspec = INT; 4467 v->u.integer = 1; 4468 return v; 4469 } 4470 4471 v->v_tspec = tn->tn_type->t_tspec; 4472 4473 if (tn->tn_op == CON) { 4474 lint_assert(tn->tn_type->t_tspec == tn->u.value.v_tspec); 4475 if (is_integer(tn->u.value.v_tspec)) { 4476 v->v_unsigned_since_c90 = 4477 tn->u.value.v_unsigned_since_c90; 4478 v->u.integer = tn->u.value.u.integer; 4479 return v; 4480 } 4481 v->u.integer = (int64_t)tn->u.value.u.floating; 4482 } else 4483 v->u.integer = 1; 4484 4485 if (required) 4486 /* integral constant expression expected */ 4487 error(55); 4488 else 4489 /* variable array dimension is a C99/GCC extension */ 4490 c99ism(318); 4491 4492 if (!is_integer(v->v_tspec)) 4493 v->v_tspec = INT; 4494 4495 return v; 4496 } 4497 4498 static bool 4499 is_constcond_false(const tnode_t *tn, tspec_t t) 4500 { 4501 return (t == BOOL || t == INT) && 4502 tn->tn_op == CON && tn->u.value.u.integer == 0; 4503 } 4504 4505 /* 4506 * Perform some tests on expressions which can't be done in build_binary() 4507 * and functions called by build_binary(). These tests must be done here 4508 * because we need some information about the context in which the operations 4509 * are performed. 4510 * After all tests are performed and dofreeblk is true, expr() frees the 4511 * memory which is used for the expression. 4512 */ 4513 void 4514 expr(tnode_t *tn, bool vctx, bool cond, bool dofreeblk, bool is_do_while, 4515 const char *stmt_kind) 4516 { 4517 4518 if (tn == NULL) { /* in case of errors */ 4519 expr_free_all(); 4520 return; 4521 } 4522 4523 /* expr() is also called in global initializations */ 4524 if (dcs->d_kind != DLK_EXTERN && !is_do_while) 4525 check_statement_reachable(stmt_kind); 4526 4527 check_expr_misc(tn, vctx, cond, !cond, false, false, false); 4528 if (tn->tn_op == ASSIGN && !tn->tn_parenthesized) { 4529 if (hflag && cond) 4530 /* assignment in conditional context */ 4531 warning(159); 4532 } else if (tn->tn_op == CON) { 4533 if (hflag && cond && !suppress_constcond && 4534 !tn->tn_system_dependent && 4535 !(is_do_while && 4536 is_constcond_false(tn, tn->tn_type->t_tspec))) 4537 /* constant in conditional context */ 4538 warning(161); 4539 } 4540 if (!modtab[tn->tn_op].m_has_side_effect) { 4541 /* 4542 * for left operands of COMMA this warning is already printed 4543 */ 4544 if (tn->tn_op != COMMA && !vctx && !cond) 4545 check_null_effect(tn); 4546 } 4547 debug_node(tn); 4548 4549 if (dofreeblk) 4550 expr_free_all(); 4551 } 4552 4553 /* If the expression has the form '*(arr + idx)', check the array index. */ 4554 static void 4555 check_array_index(const tnode_t *indir, bool taking_address) 4556 { 4557 const tnode_t *plus, *arr, *idx; 4558 4559 if (indir->tn_op == INDIR 4560 && (plus = indir->u.ops.left, plus->tn_op == PLUS) 4561 && plus->u.ops.left->tn_op == ADDR 4562 && (arr = plus->u.ops.left->u.ops.left, true) 4563 && (arr->tn_op == STRING || arr->tn_op == NAME) 4564 && arr->tn_type->t_tspec == ARRAY 4565 && (idx = plus->u.ops.right, idx->tn_op == CON) 4566 && (!is_incomplete(arr->tn_type) || idx->u.value.u.integer < 0)) 4567 goto proceed; 4568 return; 4569 4570 proceed:; 4571 int elsz = length_in_bits(arr->tn_type->t_subt, NULL); 4572 if (elsz == 0) 4573 return; 4574 elsz /= CHAR_SIZE; 4575 4576 /* Change the unit of the index from bytes to element size. */ 4577 int64_t con = is_uinteger(idx->tn_type->t_tspec) 4578 ? (int64_t)((uint64_t)idx->u.value.u.integer / elsz) 4579 : idx->u.value.u.integer / elsz; 4580 4581 int dim = arr->tn_type->u.dimension + (taking_address ? 1 : 0); 4582 4583 if (!is_uinteger(idx->tn_type->t_tspec) && con < 0) 4584 /* array subscript %jd cannot be negative */ 4585 warning(167, (intmax_t)con); 4586 else if (dim > 0 && (uint64_t)con >= (uint64_t)dim) 4587 /* array subscript %ju cannot be > %d */ 4588 warning(168, (uintmax_t)con, dim - 1); 4589 } 4590 4591 static void 4592 check_expr_addr(const tnode_t *ln, bool szof, bool fcall) 4593 { 4594 /* XXX: Taking warn_about_unreachable into account here feels wrong. */ 4595 if (ln->tn_op == NAME && (reached || !warn_about_unreachable)) { 4596 if (!szof) 4597 mark_as_set(ln->u.sym); 4598 mark_as_used(ln->u.sym, fcall, szof); 4599 } 4600 check_array_index(ln, true); 4601 } 4602 4603 /* 4604 * If there is an asm statement in one of the compound statements around, 4605 * there may be other side effects, so don't warn. 4606 */ 4607 static bool 4608 is_asm_around(void) 4609 { 4610 for (decl_level *dl = dcs; dl != NULL; dl = dl->d_enclosing) 4611 if (dl->d_asm) 4612 return true; 4613 return false; 4614 } 4615 4616 static void 4617 check_expr_side_effect(const tnode_t *ln, bool szof) 4618 { 4619 4620 /* XXX: Taking warn_about_unreachable into account here feels wrong. */ 4621 if (ln->tn_op == NAME && (reached || !warn_about_unreachable)) { 4622 scl_t sc = ln->u.sym->s_scl; 4623 if (sc != EXTERN && sc != STATIC && 4624 !ln->u.sym->s_set && !szof && !is_asm_around()) { 4625 /* '%s' may be used before set */ 4626 warning(158, ln->u.sym->s_name); 4627 mark_as_set(ln->u.sym); 4628 } 4629 mark_as_used(ln->u.sym, false, false); 4630 } 4631 } 4632 4633 static void 4634 check_expr_assign(const tnode_t *ln, bool szof) 4635 { 4636 /* XXX: Taking warn_about_unreachable into account here feels wrong. */ 4637 if (ln->tn_op == NAME && !szof && (reached || !warn_about_unreachable)) { 4638 mark_as_set(ln->u.sym); 4639 if (ln->u.sym->s_scl == EXTERN) 4640 outusg(ln->u.sym); 4641 } 4642 check_array_index(ln, false); 4643 } 4644 4645 static void 4646 check_expr_call(const tnode_t *tn, const tnode_t *ln, 4647 bool szof, bool vctx, bool cond, bool retval_discarded) 4648 { 4649 lint_assert(ln->tn_op == ADDR); 4650 lint_assert(ln->u.ops.left->tn_op == NAME); 4651 if (!szof && !is_compiler_builtin(ln->u.ops.left->u.sym->s_name)) 4652 outcall(tn, vctx || cond, retval_discarded); 4653 4654 const function_call *call = tn->u.call; 4655 if (call->args_len == 4 || call->args_len == 5) 4656 check_snprintb(call); 4657 } 4658 4659 static void 4660 check_expr_op(op_t op, const tnode_t *ln, bool szof, bool fcall, bool eqwarn) 4661 { 4662 switch (op) { 4663 case ADDR: 4664 check_expr_addr(ln, szof, fcall); 4665 break; 4666 case LOAD: 4667 check_array_index(ln, false); 4668 /* FALLTHROUGH */ 4669 case INCBEF: 4670 case DECBEF: 4671 case INCAFT: 4672 case DECAFT: 4673 case ADDASS: 4674 case SUBASS: 4675 case MULASS: 4676 case DIVASS: 4677 case MODASS: 4678 case ANDASS: 4679 case ORASS: 4680 case XORASS: 4681 case SHLASS: 4682 case SHRASS: 4683 case REAL: 4684 case IMAG: 4685 check_expr_side_effect(ln, szof); 4686 break; 4687 case ASSIGN: 4688 check_expr_assign(ln, szof); 4689 break; 4690 case EQ: 4691 if (hflag && eqwarn) 4692 /* operator '==' found where '=' was expected */ 4693 warning(160); 4694 break; 4695 default: 4696 break; 4697 } 4698 } 4699 4700 /* 4701 * vctx ??? 4702 * cond whether the expression is a condition that 4703 * will be compared with 0 4704 * eqwarn whether the operator '==' might be a 4705 * misspelled '=' 4706 * fcall whether the expression is a function call 4707 * retval_discarded whether the return value of a function call 4708 * is discarded; such calls will be analyzed by 4709 * lint2 in messages 4, 8 and 9 4710 * szof whether the expression is part of a sizeof 4711 * expression, which means that its value is 4712 * discarded since only the type is relevant 4713 */ 4714 void 4715 check_expr_misc(const tnode_t *tn, bool vctx, bool cond, 4716 bool eqwarn, bool fcall, bool retval_discarded, bool szof) 4717 { 4718 4719 if (tn == NULL) 4720 return; 4721 op_t op = tn->tn_op; 4722 if (op == NAME || op == CON || op == STRING) 4723 return; 4724 bool is_direct = op == CALL 4725 && tn->u.call->func->tn_op == ADDR 4726 && tn->u.call->func->u.ops.left->tn_op == NAME; 4727 if (op == CALL) { 4728 const function_call *call = tn->u.call; 4729 if (is_direct) 4730 check_expr_call(tn, call->func, 4731 szof, vctx, cond, retval_discarded); 4732 bool discard = op == CVT && tn->tn_type->t_tspec == VOID; 4733 check_expr_misc(call->func, false, false, false, is_direct, 4734 discard, szof); 4735 for (size_t i = 0, n = call->args_len; i < n; i++) 4736 check_expr_misc(call->args[i], 4737 true, false, false, false, false, szof); 4738 return; 4739 } 4740 4741 lint_assert(has_operands(tn)); 4742 tnode_t *ln = tn->u.ops.left; 4743 tnode_t *rn = tn->u.ops.right; 4744 check_expr_op(op, ln, szof, fcall, eqwarn); 4745 4746 const mod_t *mp = &modtab[op]; 4747 bool cvctx = mp->m_value_context; 4748 bool ccond = mp->m_compares_with_zero; 4749 bool eq = mp->m_warn_if_operand_eq && 4750 !ln->tn_parenthesized && 4751 rn != NULL && !rn->tn_parenthesized; 4752 4753 /* 4754 * Values of operands of ':' are not used if the type of at least 4755 * one of the operands (for GCC compatibility) is 'void'. 4756 * 4757 * XXX test/value context of QUEST should probably be used as 4758 * context for both operands of COLON. 4759 */ 4760 if (op == COLON && tn->tn_type->t_tspec == VOID) 4761 cvctx = ccond = false; 4762 bool discard = op == CVT && tn->tn_type->t_tspec == VOID; 4763 check_expr_misc(ln, cvctx, ccond, eq, is_direct, discard, szof); 4764 4765 switch (op) { 4766 case LOGAND: 4767 case LOGOR: 4768 check_expr_misc(rn, false, true, eq, false, false, szof); 4769 break; 4770 case COLON: 4771 check_expr_misc(rn, cvctx, ccond, eq, false, false, szof); 4772 break; 4773 case COMMA: 4774 check_expr_misc(rn, vctx, cond, false, false, false, szof); 4775 break; 4776 default: 4777 if (mp->m_binary) 4778 check_expr_misc(rn, true, false, eq, false, false, 4779 szof); 4780 break; 4781 } 4782 } 4783 4784 /* 4785 * Return whether the expression can be used for static initialization. 4786 * 4787 * Constant initialization expressions must be constant or an address 4788 * of a static object with an optional offset. In the first case, 4789 * the result is returned in *offsp. In the second case, the static 4790 * object is returned in *symp and the offset in *offsp. 4791 * 4792 * The expression can consist of PLUS, MINUS, ADDR, NAME, STRING and 4793 * CON. Type conversions are allowed if they do not change binary 4794 * representation (including width). 4795 * 4796 * C99 6.6 "Constant expressions" 4797 * C99 6.7.8p4 restricts initializers for static storage duration 4798 */ 4799 bool 4800 constant_addr(const tnode_t *tn, const sym_t **symp, ptrdiff_t *offsp) 4801 { 4802 const sym_t *sym; 4803 ptrdiff_t offs1, offs2; 4804 tspec_t t, ot; 4805 4806 switch (tn->tn_op) { 4807 case MINUS: 4808 if (tn->u.ops.right->tn_op == CVT) 4809 return constant_addr(tn->u.ops.right, symp, offsp); 4810 else if (tn->u.ops.right->tn_op != CON) 4811 return false; 4812 /* FALLTHROUGH */ 4813 case PLUS: 4814 offs1 = offs2 = 0; 4815 if (tn->u.ops.left->tn_op == CON) { 4816 offs1 = (ptrdiff_t)tn->u.ops.left->u.value.u.integer; 4817 if (!constant_addr(tn->u.ops.right, &sym, &offs2)) 4818 return false; 4819 } else if (tn->u.ops.right->tn_op == CON) { 4820 offs2 = (ptrdiff_t)tn->u.ops.right->u.value.u.integer; 4821 if (tn->tn_op == MINUS) 4822 offs2 = -offs2; 4823 if (!constant_addr(tn->u.ops.left, &sym, &offs1)) 4824 return false; 4825 } else { 4826 return false; 4827 } 4828 *symp = sym; 4829 *offsp = offs1 + offs2; 4830 return true; 4831 case ADDR: 4832 if (tn->u.ops.left->tn_op == NAME) { 4833 *symp = tn->u.ops.left->u.sym; 4834 *offsp = 0; 4835 return true; 4836 } else { 4837 /* 4838 * If this were the front end of a compiler, we would 4839 * return a label instead of 0, at least if 4840 * 'tn->u.ops.left->tn_op == STRING'. 4841 */ 4842 *symp = NULL; 4843 *offsp = 0; 4844 return true; 4845 } 4846 case CVT: 4847 t = tn->tn_type->t_tspec; 4848 ot = tn->u.ops.left->tn_type->t_tspec; 4849 if ((!is_integer(t) && t != PTR) || 4850 (!is_integer(ot) && ot != PTR)) { 4851 return false; 4852 } 4853 #if 0 4854 /*- 4855 * consider: 4856 * struct foo { 4857 * unsigned char a; 4858 * } f = { 4859 * (unsigned char)(unsigned long) 4860 * (&(((struct foo *)0)->a)) 4861 * }; 4862 * since psize(unsigned long) != psize(unsigned char), 4863 * this fails. 4864 */ 4865 else if (psize(t) != psize(ot)) 4866 return -1; 4867 #endif 4868 return constant_addr(tn->u.ops.left, symp, offsp); 4869 default: 4870 return false; 4871 } 4872 } 4873 4874 /* Append s2 to s1, then free s2. */ 4875 buffer * 4876 cat_strings(buffer *s1, buffer *s2) 4877 { 4878 4879 if ((s1->data != NULL) != (s2->data != NULL)) { 4880 /* cannot concatenate wide and regular string literals */ 4881 error(292); 4882 return s1; 4883 } 4884 4885 if (s1->data != NULL) { 4886 while (s1->len + s2->len + 1 > s1->cap) 4887 s1->cap *= 2; 4888 s1->data = xrealloc(s1->data, s1->cap); 4889 memcpy(s1->data + s1->len, s2->data, s2->len + 1); 4890 free(s2->data); 4891 } 4892 s1->len += s2->len; 4893 free(s2); 4894 4895 return s1; 4896 } 4897 4898 4899 typedef struct stmt_expr { 4900 memory_pool se_mem; 4901 sym_t *se_sym; 4902 struct stmt_expr *se_enclosing; 4903 } stmt_expr; 4904 4905 static stmt_expr *stmt_exprs; 4906 4907 void 4908 begin_statement_expr(void) 4909 { 4910 debug_enter(); 4911 4912 stmt_expr *se = xmalloc(sizeof(*se)); 4913 se->se_mem = expr_save_memory(); 4914 se->se_sym = NULL; 4915 se->se_enclosing = stmt_exprs; 4916 stmt_exprs = se; 4917 } 4918 4919 void 4920 do_statement_expr(tnode_t *tn) 4921 { 4922 block_level--; 4923 mem_block_level--; 4924 stmt_exprs->se_sym = tn != NULL 4925 ? mktempsym(block_dup_type(tn->tn_type)) 4926 : NULL; /* after a syntax error */ 4927 mem_block_level++; 4928 block_level++; 4929 /* '({ ... })' is a GCC extension */ 4930 gnuism(320); 4931 } 4932 4933 tnode_t * 4934 end_statement_expr(void) 4935 { 4936 tnode_t *tn; 4937 4938 stmt_expr *se = stmt_exprs; 4939 if (se->se_sym == NULL) { 4940 tn = NULL; /* after a syntax error */ 4941 goto end; 4942 } 4943 4944 tn = build_name(se->se_sym, false); 4945 (void)expr_save_memory(); /* leak */ 4946 expr_restore_memory(se->se_mem); 4947 stmt_exprs = se->se_enclosing; 4948 free(se); 4949 4950 end: 4951 debug_leave(); 4952 return tn; 4953 } 4954 4955 bool 4956 in_statement_expr(void) 4957 { 4958 return stmt_exprs != NULL; 4959 } 4960
Indexes created Sun Sep 21 16:09:51 GMT 2025