tree.c revision 1.658
1 /* $NetBSD: tree.c,v 1.658 2024/11/13 04:32:49 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 1.658 2024/11/13 04:32:49 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 (any_query_enabled && 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 1493 if ((op == ADDASS || op == SUBASS) && lt == PTR) { 1494 lint_assert(is_integer(rt)); 1495 tnode_t *ctn = subt_size_in_bytes(ln->tn_type); 1496 if (rn->tn_type->t_tspec != ctn->tn_type->t_tspec) 1497 rn = convert(NOOP, 0, ctn->tn_type, rn); 1498 rn = build_op(MULT, sys, rn->tn_type, rn, ctn); 1499 if (rn->u.ops.left->tn_op == CON) 1500 rn = fold_constant_integer(rn); 1501 } 1502 1503 if ((op == ASSIGN || op == RETURN || op == INIT) && 1504 (lt == STRUCT || rt == STRUCT)) { 1505 lint_assert(lt == rt); 1506 lint_assert(ln->tn_type->u.sou == rn->tn_type->u.sou); 1507 if (is_incomplete(ln->tn_type)) { 1508 if (op == RETURN) 1509 /* cannot return incomplete type */ 1510 error(212); 1511 else 1512 /* unknown operand size, op '%s' */ 1513 error(138, op_name(op)); 1514 return NULL; 1515 } 1516 } 1517 1518 if (op == SHLASS && hflag && allow_trad && allow_c90 1519 && portable_rank_cmp(lt, rt) < 0) 1520 /* semantics of '%s' change in C90; ... */ 1521 warning(118, "<<="); 1522 1523 if (op != SHLASS && op != SHRASS 1524 && (op == ASSIGN || lt != PTR) 1525 && (lt != rt || (ln->tn_type->t_bitfield && rn->tn_op == CON))) { 1526 rn = convert(op, 0, ln->tn_type, rn); 1527 rt = lt; 1528 } 1529 1530 if (is_query_enabled[20] 1531 && lt == PTR && ln->tn_type->t_subt->t_tspec != VOID 1532 && rt == PTR && rn->tn_type->t_subt->t_tspec == VOID 1533 && !is_null_pointer(rn)) 1534 /* implicit narrowing conversion from void ... */ 1535 query_message(20, type_name(ln->tn_type)); 1536 1537 if (any_query_enabled && rn->tn_op == CVT && rn->tn_cast && 1538 types_compatible(ln->tn_type, rn->tn_type, false, false, NULL) && 1539 is_cast_redundant(rn)) { 1540 /* redundant cast from '%s' to '%s' before assignment */ 1541 query_message(7, type_name(rn->u.ops.left->tn_type), 1542 type_name(rn->tn_type)); 1543 } 1544 1545 return build_op(op, sys, ln->tn_type, ln, rn); 1546 } 1547 1548 static tnode_t * 1549 build_real_imag(op_t op, bool sys, tnode_t *ln) 1550 { 1551 1552 lint_assert(ln != NULL); 1553 if (ln->tn_op == NAME) { 1554 /* 1555 * This may be too much, but it avoids wrong warnings. See 1556 * d_c99_complex_split.c. 1557 */ 1558 mark_as_used(ln->u.sym, false, false); 1559 mark_as_set(ln->u.sym); 1560 } 1561 1562 tspec_t t; 1563 switch (ln->tn_type->t_tspec) { 1564 case LCOMPLEX: 1565 t = LDOUBLE; 1566 break; 1567 case DCOMPLEX: 1568 t = DOUBLE; 1569 break; 1570 case FCOMPLEX: 1571 t = FLOAT; 1572 break; 1573 default: 1574 /* '__%s__' is illegal for type '%s' */ 1575 error(276, op == REAL ? "real" : "imag", 1576 type_name(ln->tn_type)); 1577 return NULL; 1578 } 1579 1580 tnode_t *ntn = build_op(op, sys, gettyp(t), ln, NULL); 1581 ntn->tn_lvalue = true; 1582 return ntn; 1583 } 1584 1585 static bool 1586 is_confusing_precedence(op_t op, op_t lop, bool lparen, op_t rop, bool rparen) 1587 { 1588 1589 if (op == SHL || op == SHR) { 1590 if (!lparen && (lop == PLUS || lop == MINUS)) 1591 return true; 1592 if (!rparen && (rop == PLUS || rop == MINUS)) 1593 return true; 1594 return false; 1595 } 1596 1597 if (op == LOGOR) { 1598 if (!lparen && lop == LOGAND) 1599 return true; 1600 if (!rparen && rop == LOGAND) 1601 return true; 1602 return false; 1603 } 1604 1605 lint_assert(op == BITAND || op == BITXOR || op == BITOR); 1606 if (!lparen && lop != op) { 1607 if (lop == PLUS || lop == MINUS) 1608 return true; 1609 if (lop == BITAND || lop == BITXOR) 1610 return true; 1611 } 1612 if (!rparen && rop != op) { 1613 if (rop == PLUS || rop == MINUS) 1614 return true; 1615 if (rop == BITAND || rop == BITXOR) 1616 return true; 1617 } 1618 return false; 1619 } 1620 1621 /* 1622 * Print a warning if the given node has operands which should be 1623 * parenthesized. 1624 * 1625 * XXX Does not work if an operand is a constant expression. Constant 1626 * expressions are already folded. 1627 */ 1628 static void 1629 check_precedence_confusion(tnode_t *tn) 1630 { 1631 tnode_t *ln, *rn; 1632 1633 if (!hflag) 1634 return; 1635 1636 debug_node(tn); 1637 1638 lint_assert(is_binary(tn)); 1639 for (ln = tn->u.ops.left; ln->tn_op == CVT; ln = ln->u.ops.left) 1640 continue; 1641 for (rn = tn->u.ops.right; rn->tn_op == CVT; rn = rn->u.ops.left) 1642 continue; 1643 1644 if (is_confusing_precedence(tn->tn_op, 1645 ln->tn_op, ln->tn_parenthesized, 1646 rn->tn_op, rn->tn_parenthesized)) { 1647 /* precedence confusion possible: parenthesize! */ 1648 warning(169); 1649 } 1650 } 1651 1652 static tnode_t * 1653 fold_constant_compare_zero(tnode_t *tn) 1654 { 1655 1656 val_t *v = xcalloc(1, sizeof(*v)); 1657 v->v_tspec = tn->tn_type->t_tspec; 1658 lint_assert(v->v_tspec == INT || (Tflag && v->v_tspec == BOOL)); 1659 1660 lint_assert(has_operands(tn)); 1661 bool l = constant_is_nonzero(tn->u.ops.left); 1662 bool r = is_binary(tn) && constant_is_nonzero(tn->u.ops.right); 1663 1664 switch (tn->tn_op) { 1665 case NOT: 1666 if (hflag && !suppress_constcond) 1667 /* constant operand to '!' */ 1668 warning(239); 1669 v->u.integer = !l ? 1 : 0; 1670 break; 1671 case LOGAND: 1672 v->u.integer = l && r ? 1 : 0; 1673 break; 1674 case LOGOR: 1675 v->u.integer = l || r ? 1 : 0; 1676 break; 1677 default: 1678 lint_assert(/*CONSTCOND*/false); 1679 } 1680 1681 return build_constant(tn->tn_type, v); 1682 } 1683 1684 static long double 1685 floating_error_value(tspec_t t, long double lv) 1686 { 1687 if (t == FLOAT) 1688 return lv < 0 ? -FLT_MAX : FLT_MAX; 1689 if (t == DOUBLE) 1690 return lv < 0 ? -DBL_MAX : DBL_MAX; 1691 /* 1692 * When NetBSD is cross-built in MKLINT=yes mode on x86_64 for sparc64, 1693 * tools/lint checks this code while building usr.bin/xlint. In that 1694 * situation, lint uses the preprocessor for sparc64, in which the type 1695 * 'long double' is IEEE-754-binary128, affecting the macro LDBL_MAX 1696 * below. The type 'long double', as well as the strtold 1697 * implementation, comes from the host platform x86_64 though, where 1698 * 'long double' consumes 128 bits as well but only uses 80 of them. 1699 * The exponent range of the two 'long double' types is the same, but 1700 * the maximum finite value differs due to the extended precision on 1701 * sparc64. 1702 * 1703 * To properly handle the data types of the target platform, lint would 1704 * have to implement the floating-point types in a platform-independent 1705 * way, which is not worth the effort, given how few programs 1706 * practically use 'long double'. 1707 */ 1708 /* LINTED 248: floating-point constant out of range */ 1709 long double max = LDBL_MAX; 1710 return lv < 0 ? -max : max; 1711 } 1712 1713 static bool 1714 is_floating_overflow(tspec_t t, long double val) 1715 { 1716 if (fpe != 0 || isfinite(val) == 0) 1717 return true; 1718 if (t == FLOAT && (val > FLT_MAX || val < -FLT_MAX)) 1719 return true; 1720 if (t == DOUBLE && (val > DBL_MAX || val < -DBL_MAX)) 1721 return true; 1722 return false; 1723 } 1724 1725 static tnode_t * 1726 fold_constant_floating(tnode_t *tn) 1727 { 1728 1729 fpe = 0; 1730 1731 tspec_t t = tn->tn_type->t_tspec; 1732 1733 val_t *v = xcalloc(1, sizeof(*v)); 1734 v->v_tspec = t; 1735 1736 lint_assert(is_floating(t)); 1737 lint_assert(has_operands(tn)); 1738 lint_assert(t == tn->u.ops.left->tn_type->t_tspec); 1739 lint_assert(!is_binary(tn) || t == tn->u.ops.right->tn_type->t_tspec); 1740 1741 long double lv = tn->u.ops.left->u.value.u.floating; 1742 long double rv = is_binary(tn) ? tn->u.ops.right->u.value.u.floating 1743 : 0.0; 1744 1745 switch (tn->tn_op) { 1746 case UPLUS: 1747 v->u.floating = lv; 1748 break; 1749 case UMINUS: 1750 v->u.floating = -lv; 1751 break; 1752 case MULT: 1753 v->u.floating = lv * rv; 1754 break; 1755 case DIV: 1756 if (rv == 0.0) { 1757 /* division by 0 */ 1758 error(139); 1759 v->u.floating = floating_error_value(t, lv); 1760 } else { 1761 v->u.floating = lv / rv; 1762 } 1763 break; 1764 case PLUS: 1765 v->u.floating = lv + rv; 1766 break; 1767 case MINUS: 1768 v->u.floating = lv - rv; 1769 break; 1770 case LT: 1771 v->u.integer = lv < rv ? 1 : 0; 1772 break; 1773 case LE: 1774 v->u.integer = lv <= rv ? 1 : 0; 1775 break; 1776 case GE: 1777 v->u.integer = lv >= rv ? 1 : 0; 1778 break; 1779 case GT: 1780 v->u.integer = lv > rv ? 1 : 0; 1781 break; 1782 case EQ: 1783 v->u.integer = lv == rv ? 1 : 0; 1784 break; 1785 case NE: 1786 v->u.integer = lv != rv ? 1 : 0; 1787 break; 1788 default: 1789 lint_assert(/*CONSTCOND*/false); 1790 } 1791 1792 // XXX: Must not access u.floating after setting u.integer. 1793 lint_assert(fpe != 0 || isnan(v->u.floating) == 0); 1794 if (is_complex(v->v_tspec)) { 1795 /* 1796 * Don't warn, as lint doesn't model the imaginary part of 1797 * complex numbers. 1798 */ 1799 fpe = 0; 1800 } else if (is_floating_overflow(t, v->u.floating)) { 1801 /* operator '%s' produces floating point overflow */ 1802 warning(142, op_name(tn->tn_op)); 1803 v->u.floating = floating_error_value(t, v->u.floating); 1804 fpe = 0; 1805 } 1806 1807 return build_constant(tn->tn_type, v); 1808 } 1809 1810 static void 1811 use(const tnode_t *tn) 1812 { 1813 if (tn == NULL) 1814 return; 1815 switch (tn->tn_op) { 1816 case NAME: 1817 mark_as_used(tn->u.sym, false /* XXX */, false /* XXX */); 1818 break; 1819 case CON: 1820 case STRING: 1821 break; 1822 case CALL:; 1823 const function_call *call = tn->u.call; 1824 for (size_t i = 0, n = call->args_len; i < n; i++) 1825 use(call->args[i]); 1826 break; 1827 default: 1828 lint_assert(has_operands(tn)); 1829 use(tn->u.ops.left); 1830 if (is_binary(tn)) 1831 use(tn->u.ops.right); 1832 } 1833 } 1834 1835 /* 1836 * Create a tree node for a binary operator and its two operands. Also called 1837 * for unary operators; in that case rn is NULL. 1838 * 1839 * Function calls, sizeof and casts are handled elsewhere. 1840 */ 1841 tnode_t * 1842 build_binary(tnode_t *ln, op_t op, bool sys, tnode_t *rn) 1843 { 1844 const mod_t *mp = &modtab[op]; 1845 1846 /* If there was an error in one of the operands, return. */ 1847 if (ln == NULL || (mp->m_binary && rn == NULL)) 1848 return NULL; 1849 1850 if (mp->m_value_context || mp->m_compares_with_zero) 1851 ln = cconv(ln); 1852 if (mp->m_binary && op != ARROW && op != POINT) 1853 rn = cconv(rn); 1854 1855 if (mp->m_comparison) 1856 check_integer_comparison(op, ln, rn); 1857 1858 if (mp->m_value_context || mp->m_compares_with_zero) 1859 ln = promote(op, false, ln); 1860 if (mp->m_binary && op != ARROW && op != POINT && 1861 op != ASSIGN && op != RETURN && op != INIT) 1862 rn = promote(op, false, rn); 1863 1864 if (mp->m_warn_if_left_unsigned_in_c90 && 1865 ln->tn_op == CON && ln->u.value.v_unsigned_since_c90) { 1866 /* C90 treats constant as unsigned, op '%s' */ 1867 warning(218, op_name(op)); 1868 ln->u.value.v_unsigned_since_c90 = false; 1869 } 1870 if (mp->m_warn_if_right_unsigned_in_c90 && 1871 rn->tn_op == CON && rn->u.value.v_unsigned_since_c90) { 1872 /* C90 treats constant as unsigned, op '%s' */ 1873 warning(218, op_name(op)); 1874 rn->u.value.v_unsigned_since_c90 = false; 1875 } 1876 1877 if (mp->m_balance_operands || (!allow_c90 && (op == SHL || op == SHR))) 1878 balance(op, &ln, &rn); 1879 1880 if (!typeok(op, 0, ln, rn)) 1881 return NULL; 1882 1883 tnode_t *ntn; 1884 switch (op) { 1885 case POINT: 1886 case ARROW: 1887 ntn = build_struct_access(op, sys, ln, rn); 1888 break; 1889 case NOT: 1890 if (ln->tn_op == ASSIGN && ln->u.ops.right->tn_op == CON) { 1891 /* constant assignment of type '%s' in operand ... */ 1892 warning(382, type_name(ln->tn_type), 1893 is_nonzero_val(&ln->u.ops.right->u.value) 1894 ? "true" : "false"); 1895 } 1896 ntn = build_op(op, sys, gettyp(Tflag ? BOOL : INT), ln, NULL); 1897 break; 1898 case INCAFT: 1899 case DECAFT: 1900 case INCBEF: 1901 case DECBEF: 1902 ntn = build_prepost_incdec(op, sys, ln); 1903 break; 1904 case ADDR: 1905 ntn = build_address(sys, ln, false); 1906 break; 1907 case INDIR: 1908 ntn = build_op(INDIR, sys, ln->tn_type->t_subt, ln, NULL); 1909 break; 1910 case PLUS: 1911 case MINUS: 1912 ntn = build_plus_minus(op, sys, ln, rn); 1913 break; 1914 case SHL: 1915 case SHR: 1916 ntn = build_bit_shift(op, sys, ln, rn); 1917 break; 1918 case COLON: 1919 ntn = build_colon(sys, ln, rn); 1920 break; 1921 case ASSIGN: 1922 case MULASS: 1923 case DIVASS: 1924 case MODASS: 1925 case ADDASS: 1926 case SUBASS: 1927 case SHLASS: 1928 case SHRASS: 1929 case ANDASS: 1930 case XORASS: 1931 case ORASS: 1932 case RETURN: 1933 case INIT: 1934 ntn = build_assignment(op, sys, ln, rn); 1935 break; 1936 case COMMA: 1937 if (any_query_enabled) { 1938 /* comma operator with types '%s' and '%s' */ 1939 query_message(12, 1940 type_name(ln->tn_type), type_name(rn->tn_type)); 1941 } 1942 /* FALLTHROUGH */ 1943 case QUEST: 1944 ntn = build_op(op, sys, rn->tn_type, ln, rn); 1945 break; 1946 case REAL: 1947 case IMAG: 1948 ntn = build_real_imag(op, sys, ln); 1949 break; 1950 default: 1951 lint_assert(mp->m_binary == (rn != NULL)); 1952 type_t *rettp = mp->m_returns_bool 1953 ? gettyp(Tflag ? BOOL : INT) : ln->tn_type; 1954 ntn = build_op(op, sys, rettp, ln, rn); 1955 break; 1956 } 1957 1958 if (ntn == NULL) 1959 return NULL; 1960 1961 if (mp->m_possible_precedence_confusion) 1962 check_precedence_confusion(ntn); 1963 1964 if (hflag && !suppress_constcond && 1965 mp->m_compares_with_zero && 1966 (ln->tn_op == CON || 1967 (mp->m_binary && op != QUEST && rn->tn_op == CON)) && 1968 /* XXX: rn->tn_system_dependent should be checked as well */ 1969 !ln->tn_system_dependent) 1970 /* constant in conditional context */ 1971 warning(161); 1972 1973 if (mp->m_fold_constant_operands && ln->tn_op == CON) { 1974 if (!mp->m_binary || rn->tn_op == CON) { 1975 if (mp->m_compares_with_zero) 1976 ntn = fold_constant_compare_zero(ntn); 1977 else if (is_floating(ntn->tn_type->t_tspec)) 1978 ntn = fold_constant_floating(ntn); 1979 else 1980 ntn = fold_constant_integer(ntn); 1981 } else if (op == QUEST) { 1982 lint_assert(has_operands(rn)); 1983 use(ln->u.value.u.integer != 0 1984 ? rn->u.ops.right : rn->u.ops.left); 1985 ntn = ln->u.value.u.integer != 0 1986 ? rn->u.ops.left : rn->u.ops.right; 1987 } 1988 } 1989 1990 return ntn; 1991 } 1992 1993 tnode_t * 1994 build_unary(op_t op, bool sys, tnode_t *tn) 1995 { 1996 return build_binary(tn, op, sys, NULL); 1997 } 1998 1999 static bool 2000 are_members_compatible(const sym_t *a, const sym_t *b) 2001 { 2002 if (a->u.s_member.sm_offset_in_bits != b->u.s_member.sm_offset_in_bits) 2003 return false; 2004 2005 const type_t *atp = a->s_type; 2006 const type_t *btp = b->s_type; 2007 bool w = false; 2008 if (!types_compatible(atp, btp, false, false, &w) && !w) 2009 return false; 2010 if (a->s_bitfield != b->s_bitfield) 2011 return false; 2012 if (a->s_bitfield) { 2013 if (atp->t_bit_field_width != btp->t_bit_field_width) 2014 return false; 2015 if (atp->t_bit_field_offset != btp->t_bit_field_offset) 2016 return false; 2017 } 2018 return true; 2019 } 2020 2021 /* 2022 * Return whether all struct/union members with the same name have the same 2023 * type and offset. 2024 */ 2025 static bool 2026 all_members_compatible(const sym_t *msym) 2027 { 2028 for (const sym_t *csym = msym; 2029 csym != NULL; csym = csym->s_symtab_next) { 2030 if (!is_member(csym)) 2031 continue; 2032 if (strcmp(msym->s_name, csym->s_name) != 0) 2033 continue; 2034 2035 for (const sym_t *sym = csym->s_symtab_next; 2036 sym != NULL; sym = sym->s_symtab_next) { 2037 if (is_member(sym) 2038 && strcmp(csym->s_name, sym->s_name) == 0 2039 && !are_members_compatible(csym, sym)) 2040 return false; 2041 } 2042 } 2043 return true; 2044 } 2045 2046 sym_t * 2047 find_member(const struct_or_union *sou, const char *name) 2048 { 2049 for (sym_t *mem = sou->sou_first_member; 2050 mem != NULL; mem = mem->s_next) { 2051 lint_assert(is_member(mem)); 2052 lint_assert(mem->u.s_member.sm_containing_type == sou); 2053 if (strcmp(mem->s_name, name) == 0) 2054 return mem; 2055 } 2056 2057 for (sym_t *mem = sou->sou_first_member; 2058 mem != NULL; mem = mem->s_next) { 2059 if (is_struct_or_union(mem->s_type->t_tspec) 2060 && mem->s_name == unnamed) { 2061 sym_t *nested_mem = 2062 find_member(mem->s_type->u.sou, name); 2063 if (nested_mem != NULL) 2064 return nested_mem; 2065 } 2066 } 2067 return NULL; 2068 } 2069 2070 /* 2071 * Remove the member if it was unknown until now, which means 2072 * that no defined struct or union has a member with the same name. 2073 */ 2074 static void 2075 remove_unknown_member(tnode_t *tn, sym_t *msym) 2076 { 2077 /* type '%s' does not have member '%s' */ 2078 error(101, type_name(tn->tn_type), msym->s_name); 2079 symtab_remove_forever(msym); 2080 msym->s_kind = SK_MEMBER; 2081 msym->s_scl = STRUCT_MEMBER; 2082 2083 struct_or_union *sou = expr_zero_alloc(sizeof(*sou), 2084 "struct_or_union"); 2085 sou->sou_tag = expr_zero_alloc(sizeof(*sou->sou_tag), "sym"); 2086 sou->sou_tag->s_name = unnamed; 2087 2088 msym->u.s_member.sm_containing_type = sou; 2089 /* 2090 * The member sm_offset_in_bits is not needed here since this symbol 2091 * can only be used for error reporting. 2092 */ 2093 } 2094 2095 /* 2096 * Returns a symbol which has the same name as 'msym' and is a member of the 2097 * struct or union specified by 'tn'. 2098 */ 2099 static sym_t * 2100 struct_or_union_member(tnode_t *tn, op_t op, sym_t *msym) 2101 { 2102 2103 /* Determine the tag type of which msym is expected to be a member. */ 2104 const type_t *tp = NULL; 2105 if (op == POINT && is_struct_or_union(tn->tn_type->t_tspec)) 2106 tp = tn->tn_type; 2107 if (op == ARROW && tn->tn_type->t_tspec == PTR 2108 && is_struct_or_union(tn->tn_type->t_subt->t_tspec)) 2109 tp = tn->tn_type->t_subt; 2110 struct_or_union *sou = tp != NULL ? tp->u.sou : NULL; 2111 2112 if (sou != NULL) { 2113 sym_t *nested_mem = find_member(sou, msym->s_name); 2114 if (nested_mem != NULL) 2115 return nested_mem; 2116 } 2117 2118 if (msym->s_scl == NO_SCL) { 2119 remove_unknown_member(tn, msym); 2120 return msym; 2121 } 2122 2123 bool eq = all_members_compatible(msym); 2124 2125 /* 2126 * Now handle the case in which the left operand refers really to a 2127 * struct/union, but the right operand is not member of it. 2128 */ 2129 if (sou != NULL) { 2130 if (eq && !allow_c90) 2131 /* illegal use of member '%s' */ 2132 warning(102, msym->s_name); 2133 else 2134 /* illegal use of member '%s' */ 2135 error(102, msym->s_name); 2136 return msym; 2137 } 2138 2139 if (eq) { 2140 if (op == POINT) { 2141 if (!allow_c90) 2142 /* left operand of '.' must be struct ... */ 2143 warning(103, type_name(tn->tn_type)); 2144 else 2145 /* left operand of '.' must be struct ... */ 2146 error(103, type_name(tn->tn_type)); 2147 } else { 2148 if (!allow_c90 && tn->tn_type->t_tspec == PTR) 2149 /* left operand of '->' must be pointer ... */ 2150 warning(104, type_name(tn->tn_type)); 2151 else 2152 /* left operand of '->' must be pointer ... */ 2153 error(104, type_name(tn->tn_type)); 2154 } 2155 } else { 2156 if (!allow_c90) 2157 /* non-unique member requires struct/union %s */ 2158 error(105, op == POINT ? "object" : "pointer"); 2159 else 2160 /* unacceptable operand of '%s' */ 2161 error(111, op_name(op)); 2162 } 2163 2164 return msym; 2165 } 2166 2167 tnode_t * 2168 build_member_access(tnode_t *ln, op_t op, bool sys, sbuf_t *member) 2169 { 2170 sym_t *msym; 2171 2172 if (ln == NULL) 2173 return NULL; 2174 2175 if (op == ARROW) 2176 /* must do this before struct_or_union_member is called */ 2177 ln = cconv(ln); 2178 msym = struct_or_union_member(ln, op, getsym(member)); 2179 return build_binary(ln, op, sys, build_name(msym, false)); 2180 } 2181 2182 /* 2183 * Perform class conversions. 2184 * 2185 * Arrays of type T are converted into pointers to type T. 2186 * Functions are converted to pointers to functions. 2187 * Lvalues are converted to rvalues. 2188 * 2189 * C99 6.3 "Conversions" 2190 * C99 6.3.2 "Other operands" 2191 * C99 6.3.2.1 "Lvalues, arrays, and function designators" 2192 */ 2193 tnode_t * 2194 cconv(tnode_t *tn) 2195 { 2196 if (tn->tn_type->t_tspec == ARRAY) { 2197 if (!tn->tn_lvalue) { 2198 /* XXX print correct operator */ 2199 /* %soperand of '%s' must be lvalue */ 2200 gnuism(114, "", op_name(ADDR)); 2201 } 2202 tn = build_op(ADDR, tn->tn_sys, 2203 expr_derive_type(tn->tn_type->t_subt, PTR), tn, NULL); 2204 } 2205 2206 if (tn->tn_type->t_tspec == FUNC) 2207 tn = build_address(tn->tn_sys, tn, true); 2208 2209 if (tn->tn_lvalue) { 2210 type_t *tp = expr_dup_type(tn->tn_type); 2211 /* C99 6.3.2.1p2 sentence 2 says to remove the qualifiers. */ 2212 tp->t_const = tp->t_volatile = false; 2213 tn = build_op(LOAD, tn->tn_sys, tp, tn, NULL); 2214 } 2215 2216 return tn; 2217 } 2218 2219 const tnode_t * 2220 before_conversion(const tnode_t *tn) 2221 { 2222 while (tn->tn_op == CVT && !tn->tn_cast) 2223 tn = tn->u.ops.left; 2224 return tn; 2225 } 2226 2227 /* 2228 * Most errors required by C90 are reported in struct_or_union_member(). 2229 * Here we only check for totally wrong things. 2230 */ 2231 static bool 2232 typeok_point(const tnode_t *ln, const type_t *ltp, tspec_t lt) 2233 { 2234 if (is_struct_or_union(lt)) 2235 return true; 2236 2237 if (lt == FUNC || lt == VOID || ltp->t_bitfield) 2238 goto wrong; 2239 2240 /* 2241 * Some C dialects from before C90 tolerated any lvalue on the 2242 * left-hand side of the '.' operator, allowing things like 'char 2243 * st[100]; st.st_mtime', assuming that the member 'st_mtime' only 2244 * occurred in a single struct; see typeok_arrow. 2245 */ 2246 if (ln->tn_lvalue) 2247 return true; 2248 2249 wrong: 2250 /* With allow_c90 we already got an error */ 2251 if (!allow_c90) 2252 /* unacceptable operand of '%s' */ 2253 error(111, op_name(POINT)); 2254 2255 return false; 2256 } 2257 2258 static bool 2259 typeok_arrow(tspec_t lt) 2260 { 2261 /* 2262 * C1978 Appendix A 14.1 says: <quote>In fact, any lvalue is allowed 2263 * before '.', and that lvalue is then assumed to have the form of the 2264 * structure of which the name of the right is a member. [...] Such 2265 * constructions are non-portable.</quote> 2266 */ 2267 if (lt == PTR || (!allow_c90 && is_integer(lt))) 2268 return true; 2269 2270 /* With allow_c90 we already got an error */ 2271 if (!allow_c90) 2272 /* unacceptable operand of '%s' */ 2273 error(111, op_name(ARROW)); 2274 return false; 2275 } 2276 2277 static bool 2278 typeok_incdec(op_t op, const tnode_t *tn, const type_t *tp) 2279 { 2280 /* operand has scalar type (checked in typeok) */ 2281 if (!tn->tn_lvalue) { 2282 if (tn->tn_op == CVT && tn->tn_cast && 2283 tn->u.ops.left->tn_op == LOAD) 2284 /* a cast does not yield an lvalue */ 2285 error(163); 2286 /* %soperand of '%s' must be lvalue */ 2287 error(114, "", op_name(op)); 2288 return false; 2289 } 2290 if (tp->t_const && allow_c90) 2291 /* %soperand of '%s' must be modifiable lvalue */ 2292 warning(115, "", op_name(op)); 2293 return true; 2294 } 2295 2296 static bool 2297 typeok_address(op_t op, const tnode_t *tn, const type_t *tp, tspec_t t) 2298 { 2299 if (t == ARRAY || t == FUNC) { 2300 /* ok, a warning comes later (in build_address()) */ 2301 } else if (!tn->tn_lvalue) { 2302 if (tn->tn_op == CVT && tn->tn_cast && 2303 tn->u.ops.left->tn_op == LOAD) 2304 /* a cast does not yield an lvalue */ 2305 error(163); 2306 /* %soperand of '%s' must be lvalue */ 2307 error(114, "", op_name(op)); 2308 return false; 2309 } else if (is_scalar(t)) { 2310 if (tp->t_bitfield) { 2311 /* cannot take address of bit-field */ 2312 error(112); 2313 return false; 2314 } 2315 } else if (t != STRUCT && t != UNION) { 2316 /* unacceptable operand of '%s' */ 2317 error(111, op_name(op)); 2318 return false; 2319 } 2320 if (tn->tn_op == NAME && tn->u.sym->s_register) { 2321 /* cannot take address of register '%s' */ 2322 error(113, tn->u.sym->s_name); 2323 return false; 2324 } 2325 return true; 2326 } 2327 2328 static bool 2329 typeok_indir(const type_t *tp, tspec_t t) 2330 { 2331 2332 if (t != PTR) { 2333 /* cannot dereference non-pointer type '%s' */ 2334 error(96, type_name(tp)); 2335 return false; 2336 } 2337 return true; 2338 } 2339 2340 static void 2341 warn_incompatible_types(op_t op, 2342 const type_t *ltp, tspec_t lt, 2343 const type_t *rtp, tspec_t rt) 2344 { 2345 bool binary = modtab[op].m_binary; 2346 2347 if (lt == VOID || (binary && rt == VOID)) { 2348 /* void type illegal in expression */ 2349 error(109); 2350 } else if (op == ASSIGN) 2351 /* cannot assign to '%s' from '%s' */ 2352 error(171, type_name(ltp), type_name(rtp)); 2353 else if (binary) 2354 /* operands of '%s' have incompatible types '%s' and '%s' */ 2355 error(107, op_name(op), type_name(ltp), type_name(rtp)); 2356 else { 2357 lint_assert(rt == NO_TSPEC); 2358 /* operand of '%s' has invalid type '%s' */ 2359 error(108, op_name(op), type_name(ltp)); 2360 } 2361 } 2362 2363 static bool 2364 typeok_plus(op_t op, 2365 const type_t *ltp, tspec_t lt, 2366 const type_t *rtp, tspec_t rt) 2367 { 2368 /* operands have scalar types (checked in typeok) */ 2369 if ((lt == PTR && !is_integer(rt)) || (rt == PTR && !is_integer(lt))) { 2370 warn_incompatible_types(op, ltp, lt, rtp, rt); 2371 return false; 2372 } 2373 return true; 2374 } 2375 2376 static bool 2377 typeok_minus(op_t op, 2378 const type_t *ltp, tspec_t lt, 2379 const type_t *rtp, tspec_t rt) 2380 { 2381 /* operands have scalar types (checked in typeok) */ 2382 if ((lt == PTR && rt != PTR && !is_integer(rt)) || 2383 (lt != PTR && rt == PTR)) { 2384 warn_incompatible_types(op, ltp, lt, rtp, rt); 2385 return false; 2386 } 2387 if (lt == PTR && rt == PTR && 2388 !types_compatible(ltp->t_subt, rtp->t_subt, true, false, NULL)) { 2389 /* illegal pointer subtraction */ 2390 error(116); 2391 } 2392 return true; 2393 } 2394 2395 static void 2396 typeok_shr(op_t op, 2397 const tnode_t *ln, tspec_t lt, 2398 const tnode_t *rn, tspec_t rt) 2399 { 2400 tspec_t olt = before_conversion(ln)->tn_type->t_tspec; 2401 tspec_t ort = before_conversion(rn)->tn_type->t_tspec; 2402 2403 /* operands have integer types (checked in typeok) */ 2404 if (pflag && !is_uinteger(olt)) { 2405 integer_constraints lc = ic_expr(ln); 2406 if (!ic_maybe_signed(ln->tn_type, &lc)) 2407 return; 2408 2409 if (ln->tn_op != CON) 2410 /* bitwise '%s' on signed value possibly nonportable */ 2411 warning(117, op_name(op)); 2412 else if (ln->u.value.u.integer < 0) 2413 /* bitwise '%s' on signed value nonportable */ 2414 warning(120, op_name(op)); 2415 } else if (allow_trad && allow_c90 && 2416 !is_uinteger(olt) && is_uinteger(ort)) { 2417 /* The left operand would become unsigned in traditional C. */ 2418 if (hflag && (ln->tn_op != CON || ln->u.value.u.integer < 0)) { 2419 /* semantics of '%s' change in C90; use ... */ 2420 warning(118, op_name(op)); 2421 } 2422 } else if (allow_trad && allow_c90 && 2423 !is_uinteger(olt) && !is_uinteger(ort) && 2424 portable_rank_cmp(lt, rt) < 0) { 2425 /* 2426 * In traditional C, the left operand would be extended 2427 * (possibly sign-extended) and then shifted. 2428 */ 2429 if (hflag && (ln->tn_op != CON || ln->u.value.u.integer < 0)) { 2430 /* semantics of '%s' change in C90; use ... */ 2431 warning(118, op_name(op)); 2432 } 2433 } 2434 } 2435 2436 static void 2437 typeok_shl(op_t op, tspec_t lt, tspec_t rt) 2438 { 2439 /* 2440 * C90 does not perform balancing for shift operations, but traditional 2441 * C does. If the width of the right operand is greater than the width 2442 * of the left operand, then in traditional C the left operand would be 2443 * extended to the width of the right operand. For SHL this may result 2444 * in different results. 2445 */ 2446 if (portable_rank_cmp(lt, rt) < 0) { 2447 /* 2448 * XXX If both operands are constant, make sure that there is 2449 * really a difference between C90 and traditional C. 2450 */ 2451 if (hflag && allow_trad && allow_c90) 2452 /* semantics of '%s' change in C90; use ... */ 2453 warning(118, op_name(op)); 2454 } 2455 } 2456 2457 static void 2458 typeok_shift(const type_t *ltp, tspec_t lt, const tnode_t *rn, tspec_t rt) 2459 { 2460 if (rn->tn_op != CON) 2461 return; 2462 2463 if (!is_uinteger(rt) && rn->u.value.u.integer < 0) 2464 /* negative shift */ 2465 warning(121); 2466 else if ((uint64_t)rn->u.value.u.integer == size_in_bits(lt)) 2467 /* shift amount %u equals bit-size of '%s' */ 2468 warning(267, (unsigned)rn->u.value.u.integer, type_name(ltp)); 2469 else if ((uint64_t)rn->u.value.u.integer > size_in_bits(lt)) { 2470 /* shift amount %llu is greater than bit-size %llu of '%s' */ 2471 warning(122, (unsigned long long)rn->u.value.u.integer, 2472 (unsigned long long)size_in_bits(lt), 2473 tspec_name(lt)); 2474 } 2475 } 2476 2477 static bool 2478 is_typeok_eq(const tnode_t *ln, tspec_t lt, const tnode_t *rn, tspec_t rt) 2479 { 2480 if (lt == PTR && is_null_pointer(rn)) 2481 return true; 2482 if (rt == PTR && is_null_pointer(ln)) 2483 return true; 2484 return false; 2485 } 2486 2487 static void 2488 warn_incompatible_pointers(op_t op, const type_t *ltp, const type_t *rtp) 2489 { 2490 lint_assert(ltp->t_tspec == PTR); 2491 lint_assert(rtp->t_tspec == PTR); 2492 2493 tspec_t lt = ltp->t_subt->t_tspec; 2494 tspec_t rt = rtp->t_subt->t_tspec; 2495 2496 if (is_struct_or_union(lt) && is_struct_or_union(rt)) { 2497 if (op == RETURN) 2498 /* illegal structure pointer combination */ 2499 warning(244); 2500 else { 2501 /* incompatible structure pointers: '%s' '%s' '%s' */ 2502 warning(245, type_name(ltp), 2503 op_name(op), type_name(rtp)); 2504 } 2505 } else { 2506 if (op == RETURN) 2507 /* illegal combination of '%s' and '%s' */ 2508 warning(184, type_name(ltp), type_name(rtp)); 2509 else { 2510 /* illegal combination of '%s' and '%s', op '%s' */ 2511 warning(124, 2512 type_name(ltp), type_name(rtp), op_name(op)); 2513 } 2514 } 2515 } 2516 2517 static void 2518 check_pointer_comparison(op_t op, const tnode_t *ln, const tnode_t *rn) 2519 { 2520 type_t *ltp = ln->tn_type, *rtp = rn->tn_type; 2521 tspec_t lst = ltp->t_subt->t_tspec, rst = rtp->t_subt->t_tspec; 2522 2523 if (lst == VOID || rst == VOID) { 2524 /* TODO: C99 behaves like C90 here. */ 2525 if (!allow_trad && !allow_c99 && 2526 (lst == FUNC || rst == FUNC)) { 2527 /* (void *)0 is already handled in typeok() */ 2528 const char *lsts, *rsts; 2529 *(lst == FUNC ? &lsts : &rsts) = "function pointer"; 2530 *(lst == VOID ? &lsts : &rsts) = "'void *'"; 2531 /* C90 or later forbid comparison of %s with %s */ 2532 warning(274, lsts, rsts); 2533 } 2534 return; 2535 } 2536 2537 if (!types_compatible(ltp->t_subt, rtp->t_subt, true, false, NULL)) { 2538 warn_incompatible_pointers(op, ltp, rtp); 2539 return; 2540 } 2541 2542 if (lst == FUNC && rst == FUNC) { 2543 /* TODO: C99 behaves like C90 here, see C99 6.5.8p2. */ 2544 if (!allow_trad && !allow_c99 && op != EQ && op != NE) 2545 /* pointers to functions can only be compared ... */ 2546 warning(125); 2547 } 2548 } 2549 2550 static bool 2551 typeok_compare(op_t op, 2552 const tnode_t *ln, const type_t *ltp, tspec_t lt, 2553 const tnode_t *rn, const type_t *rtp, tspec_t rt) 2554 { 2555 if (lt == PTR && rt == PTR) { 2556 check_pointer_comparison(op, ln, rn); 2557 return true; 2558 } 2559 2560 if (lt != PTR && rt != PTR) 2561 return true; 2562 2563 if (!is_integer(lt) && !is_integer(rt)) { 2564 warn_incompatible_types(op, ltp, lt, rtp, rt); 2565 return false; 2566 } 2567 2568 const char *lx = lt == PTR ? "pointer" : "integer"; 2569 const char *rx = rt == PTR ? "pointer" : "integer"; 2570 /* illegal combination of %s '%s' and %s '%s', op '%s' */ 2571 warning(123, lx, type_name(ltp), rx, type_name(rtp), op_name(op)); 2572 return true; 2573 } 2574 2575 static bool 2576 typeok_quest(tspec_t lt, const tnode_t *rn) 2577 { 2578 if (!is_scalar(lt)) { 2579 /* first operand of '?' must have scalar type */ 2580 error(170); 2581 return false; 2582 } 2583 lint_assert(before_conversion(rn)->tn_op == COLON); 2584 return true; 2585 } 2586 2587 static void 2588 typeok_colon_pointer(const type_t *ltp, const type_t *rtp) 2589 { 2590 type_t *lstp = ltp->t_subt; 2591 type_t *rstp = rtp->t_subt; 2592 tspec_t lst = lstp->t_tspec; 2593 tspec_t rst = rstp->t_tspec; 2594 2595 if ((lst == VOID && rst == FUNC) || (lst == FUNC && rst == VOID)) { 2596 /* (void *)0 is handled in typeok_colon */ 2597 /* TODO: C99 behaves like C90 here. */ 2598 if (!allow_trad && !allow_c99) 2599 /* conversion of %s to %s requires a cast, op %s */ 2600 warning(305, "function pointer", "'void *'", 2601 op_name(COLON)); 2602 return; 2603 } 2604 2605 if (pointer_types_are_compatible(lstp, rstp, true)) 2606 return; 2607 if (!types_compatible(lstp, rstp, true, false, NULL)) 2608 warn_incompatible_pointers(COLON, ltp, rtp); 2609 } 2610 2611 static bool 2612 typeok_colon(const tnode_t *ln, const type_t *ltp, tspec_t lt, 2613 const tnode_t *rn, const type_t *rtp, tspec_t rt) 2614 { 2615 2616 if (is_arithmetic(lt) && is_arithmetic(rt)) 2617 return true; 2618 if (lt == BOOL && rt == BOOL) 2619 return true; 2620 2621 if (lt == STRUCT && rt == STRUCT && ltp->u.sou == rtp->u.sou) 2622 return true; 2623 if (lt == UNION && rt == UNION && ltp->u.sou == rtp->u.sou) 2624 return true; 2625 2626 if (lt == PTR && is_null_pointer(rn)) 2627 return true; 2628 if (rt == PTR && is_null_pointer(ln)) 2629 return true; 2630 2631 if ((lt == PTR && is_integer(rt)) || (is_integer(lt) && rt == PTR)) { 2632 const char *lx = lt == PTR ? "pointer" : "integer"; 2633 const char *rx = rt == PTR ? "pointer" : "integer"; 2634 /* illegal combination of %s '%s' and %s '%s', op '%s' */ 2635 warning(123, lx, type_name(ltp), 2636 rx, type_name(rtp), op_name(COLON)); 2637 return true; 2638 } 2639 2640 if (lt == VOID || rt == VOID) { 2641 if (lt != VOID || rt != VOID) 2642 /* incompatible types '%s' and '%s' in conditional */ 2643 warning(126, type_name(ltp), type_name(rtp)); 2644 return true; 2645 } 2646 2647 if (lt == PTR && rt == PTR) { 2648 typeok_colon_pointer(ltp, rtp); 2649 return true; 2650 } 2651 2652 /* incompatible types '%s' and '%s' in conditional */ 2653 error(126, type_name(ltp), type_name(rtp)); 2654 return false; 2655 } 2656 2657 static bool 2658 has_constant_member(const type_t *tp) 2659 { 2660 lint_assert(is_struct_or_union(tp->t_tspec)); 2661 2662 for (sym_t *m = tp->u.sou->sou_first_member; 2663 m != NULL; m = m->s_next) { 2664 const type_t *mtp = m->s_type; 2665 if (mtp->t_const) 2666 return true; 2667 if (is_struct_or_union(mtp->t_tspec) && 2668 has_constant_member(mtp)) 2669 return true; 2670 } 2671 return false; 2672 } 2673 2674 static bool 2675 typeok_assign(op_t op, const tnode_t *ln, const type_t *ltp, tspec_t lt) 2676 { 2677 if (op == RETURN || op == INIT || op == FARG) 2678 return true; 2679 2680 if (!ln->tn_lvalue) { 2681 if (ln->tn_op == CVT && ln->tn_cast && 2682 ln->u.ops.left->tn_op == LOAD) 2683 /* a cast does not yield an lvalue */ 2684 error(163); 2685 /* %soperand of '%s' must be lvalue */ 2686 error(114, "left ", op_name(op)); 2687 return false; 2688 } else if (ltp->t_const 2689 || (is_struct_or_union(lt) && has_constant_member(ltp))) { 2690 if (allow_c90) 2691 /* %soperand of '%s' must be modifiable lvalue */ 2692 warning(115, "left ", op_name(op)); 2693 } 2694 return true; 2695 } 2696 2697 static bool 2698 typeok_scalar(op_t op, const mod_t *mp, 2699 const type_t *ltp, tspec_t lt, 2700 const type_t *rtp, tspec_t rt) 2701 { 2702 if (mp->m_takes_bool && lt == BOOL && rt == BOOL) 2703 return true; 2704 if (mp->m_requires_integer) { 2705 if (!is_integer(lt) || (mp->m_binary && !is_integer(rt))) { 2706 warn_incompatible_types(op, ltp, lt, rtp, rt); 2707 return false; 2708 } 2709 } else if (mp->m_requires_integer_or_complex) { 2710 if ((!is_integer(lt) && !is_complex(lt)) || 2711 (mp->m_binary && (!is_integer(rt) && !is_complex(rt)))) { 2712 warn_incompatible_types(op, ltp, lt, rtp, rt); 2713 return false; 2714 } 2715 } else if (mp->m_requires_scalar) { 2716 if (!is_scalar(lt) || (mp->m_binary && !is_scalar(rt))) { 2717 warn_incompatible_types(op, ltp, lt, rtp, rt); 2718 return false; 2719 } 2720 } else if (mp->m_requires_arith) { 2721 if (!is_arithmetic(lt) || 2722 (mp->m_binary && !is_arithmetic(rt))) { 2723 warn_incompatible_types(op, ltp, lt, rtp, rt); 2724 return false; 2725 } 2726 } 2727 return true; 2728 } 2729 2730 static void 2731 check_assign_void_pointer(op_t op, int arg, 2732 tspec_t lt, tspec_t lst, 2733 tspec_t rt, tspec_t rst) 2734 { 2735 2736 if (!(lt == PTR && rt == PTR && (lst == VOID || rst == VOID))) 2737 return; 2738 /* two pointers, at least one pointer to void */ 2739 2740 /* TODO: C99 behaves like C90 here. */ 2741 if (!(!allow_trad && !allow_c99 && (lst == FUNC || rst == FUNC))) 2742 return; 2743 /* comb. of ptr to func and ptr to void */ 2744 2745 const char *lts, *rts; 2746 *(lst == FUNC ? <s : &rts) = "function pointer"; 2747 *(lst == VOID ? <s : &rts) = "'void *'"; 2748 2749 switch (op) { 2750 case INIT: 2751 case RETURN: 2752 /* conversion of %s to %s requires a cast */ 2753 warning(303, rts, lts); 2754 break; 2755 case FARG: 2756 /* conversion of %s to %s requires a cast, arg #%d */ 2757 warning(304, rts, lts, arg); 2758 break; 2759 default: 2760 /* conversion of %s to %s requires a cast, op %s */ 2761 warning(305, rts, lts, op_name(op)); 2762 break; 2763 } 2764 } 2765 2766 static bool 2767 is_direct_function_call(const tnode_t *tn, const char **out_name) 2768 { 2769 2770 if (tn->tn_op == CALL 2771 && tn->u.call->func->tn_op == ADDR 2772 && tn->u.call->func->u.ops.left->tn_op == NAME) { 2773 *out_name = tn->u.call->func->u.ops.left->u.sym->s_name; 2774 return true; 2775 } 2776 return false; 2777 } 2778 2779 static bool 2780 is_unconst_function(const char *name) 2781 { 2782 2783 return strcmp(name, "memchr") == 0 || 2784 strcmp(name, "strchr") == 0 || 2785 strcmp(name, "strpbrk") == 0 || 2786 strcmp(name, "strrchr") == 0 || 2787 strcmp(name, "strstr") == 0; 2788 } 2789 2790 static bool 2791 is_const_char_pointer(const tnode_t *tn) 2792 { 2793 /* 2794 * For traditional reasons, C99 6.4.5p5 defines that string literals 2795 * have type 'char[]'. They are often implicitly converted to 'char 2796 * *', for example when they are passed as function arguments. 2797 * 2798 * C99 6.4.5p6 further defines that modifying a string that is 2799 * constructed from a string literal invokes undefined behavior. 2800 * 2801 * Out of these reasons, string literals are treated as 'effectively 2802 * const' here. 2803 */ 2804 if (tn->tn_op == CVT && 2805 tn->u.ops.left->tn_op == ADDR && 2806 tn->u.ops.left->u.ops.left->tn_op == STRING) 2807 return true; 2808 2809 const type_t *tp = before_conversion(tn)->tn_type; 2810 return tp->t_tspec == PTR && 2811 tp->t_subt->t_tspec == CHAR && 2812 tp->t_subt->t_const; 2813 } 2814 2815 static bool 2816 is_const_pointer(const tnode_t *tn) 2817 { 2818 const type_t *tp = before_conversion(tn)->tn_type; 2819 return tp->t_tspec == PTR && tp->t_subt->t_const; 2820 } 2821 2822 static void 2823 check_unconst_function(const type_t *lstp, const tnode_t *rn) 2824 { 2825 const char *function_name; 2826 2827 if (lstp->t_tspec == CHAR && !lstp->t_const && 2828 is_direct_function_call(rn, &function_name) && 2829 is_unconst_function(function_name) && 2830 rn->u.call->args_len >= 1 && 2831 is_const_char_pointer(rn->u.call->args[0])) { 2832 /* call to '%s' effectively discards 'const' from argument */ 2833 warning(346, function_name); 2834 } 2835 2836 if (!lstp->t_const && 2837 is_direct_function_call(rn, &function_name) && 2838 strcmp(function_name, "bsearch") == 0 && 2839 rn->u.call->args_len >= 2 && 2840 is_const_pointer(rn->u.call->args[1])) { 2841 /* call to '%s' effectively discards 'const' from argument */ 2842 warning(346, function_name); 2843 } 2844 } 2845 2846 static bool 2847 check_assign_void_pointer_compat(op_t op, int arg, 2848 const type_t *ltp, tspec_t lt, 2849 const type_t *lstp, tspec_t lst, 2850 const tnode_t *rn, 2851 const type_t *rtp, tspec_t rt, 2852 const type_t *rstp, tspec_t rst) 2853 { 2854 if (!(lt == PTR && rt == PTR && (lst == VOID || rst == VOID || 2855 types_compatible(lstp, rstp, 2856 true, false, NULL)))) 2857 return false; 2858 2859 /* compatible pointer types (qualifiers ignored) */ 2860 if (allow_c90 && 2861 ((!lstp->t_const && rstp->t_const) || 2862 (!lstp->t_volatile && rstp->t_volatile))) { 2863 /* left side has not all qualifiers of right */ 2864 switch (op) { 2865 case INIT: 2866 case RETURN: 2867 /* incompatible pointer types to '%s' and '%s' */ 2868 warning(182, type_name(lstp), type_name(rstp)); 2869 break; 2870 case FARG: 2871 /* converting '%s' to incompatible '%s' ... */ 2872 warning(153, 2873 type_name(rtp), type_name(ltp), arg); 2874 break; 2875 default: 2876 /* operands of '%s' have incompatible pointer ... */ 2877 warning(128, op_name(op), 2878 type_name(lstp), type_name(rstp)); 2879 break; 2880 } 2881 } 2882 2883 if (allow_c90) 2884 check_unconst_function(lstp, rn); 2885 2886 return true; 2887 } 2888 2889 static bool 2890 check_assign_pointer_integer(op_t op, int arg, 2891 const type_t *ltp, tspec_t lt, 2892 const type_t *rtp, tspec_t rt) 2893 { 2894 2895 if (!((lt == PTR && is_integer(rt)) || (is_integer(lt) && rt == PTR))) 2896 return false; 2897 2898 const char *lx = lt == PTR ? "pointer" : "integer"; 2899 const char *rx = rt == PTR ? "pointer" : "integer"; 2900 2901 switch (op) { 2902 case INIT: 2903 case RETURN: 2904 /* illegal combination of %s '%s' and %s '%s' */ 2905 warning(183, lx, type_name(ltp), rx, type_name(rtp)); 2906 break; 2907 case FARG: 2908 /* illegal combination of %s '%s' and %s '%s', arg #%d */ 2909 warning(154, 2910 lx, type_name(ltp), rx, type_name(rtp), arg); 2911 break; 2912 default: 2913 /* illegal combination of %s '%s' and %s '%s', op '%s' */ 2914 warning(123, 2915 lx, type_name(ltp), rx, type_name(rtp), op_name(op)); 2916 break; 2917 } 2918 return true; 2919 } 2920 2921 static bool 2922 check_assign_pointer(op_t op, int arg, 2923 const type_t *ltp, tspec_t lt, 2924 const type_t *rtp, tspec_t rt) 2925 { 2926 if (!(lt == PTR && rt == PTR)) 2927 return false; 2928 2929 if (op == FARG) 2930 /* converting '%s' to incompatible '%s' for ... */ 2931 warning(153, type_name(rtp), type_name(ltp), arg); 2932 else 2933 warn_incompatible_pointers(op, ltp, rtp); 2934 return true; 2935 } 2936 2937 static void 2938 warn_assign(op_t op, int arg, 2939 const type_t *ltp, tspec_t lt, 2940 const type_t *rtp, tspec_t rt) 2941 { 2942 switch (op) { 2943 case INIT: 2944 /* cannot initialize '%s' from '%s' */ 2945 error(185, type_name(ltp), type_name(rtp)); 2946 break; 2947 case RETURN: 2948 /* function has return type '%s' but returns '%s' */ 2949 error(211, type_name(ltp), type_name(rtp)); 2950 break; 2951 case FARG: 2952 /* passing '%s' to incompatible '%s', arg #%d */ 2953 warning(155, type_name(rtp), type_name(ltp), arg); 2954 break; 2955 default: 2956 warn_incompatible_types(op, ltp, lt, rtp, rt); 2957 break; 2958 } 2959 } 2960 2961 /* 2962 * Checks type compatibility for ASSIGN, INIT, FARG and RETURN 2963 * and prints warnings/errors if necessary. 2964 * Returns whether the types are (almost) compatible. 2965 */ 2966 static bool 2967 check_assign_types_compatible(op_t op, int arg, 2968 const tnode_t *ln, const tnode_t *rn) 2969 { 2970 tspec_t lt, rt, lst = NO_TSPEC, rst = NO_TSPEC; 2971 type_t *ltp, *rtp, *lstp = NULL, *rstp = NULL; 2972 2973 if ((lt = (ltp = ln->tn_type)->t_tspec) == PTR) 2974 lst = (lstp = ltp->t_subt)->t_tspec; 2975 if ((rt = (rtp = rn->tn_type)->t_tspec) == PTR) 2976 rst = (rstp = rtp->t_subt)->t_tspec; 2977 2978 if (lt == BOOL && is_scalar(rt)) /* C99 6.3.1.2 */ 2979 return true; 2980 2981 if (is_arithmetic(lt) && (is_arithmetic(rt) || rt == BOOL)) 2982 return true; 2983 2984 if (is_struct_or_union(lt) && is_struct_or_union(rt)) 2985 return ltp->u.sou == rtp->u.sou; 2986 2987 if (lt == PTR && is_null_pointer(rn)) { 2988 if (is_integer(rn->tn_type->t_tspec)) 2989 /* implicit conversion from integer 0 to pointer ... */ 2990 query_message(15, type_name(ltp)); 2991 return true; 2992 } 2993 2994 check_assign_void_pointer(op, arg, lt, lst, rt, rst); 2995 2996 if (check_assign_void_pointer_compat(op, arg, 2997 ltp, lt, lstp, lst, rn, rtp, rt, rstp, rst)) 2998 return true; 2999 3000 if (check_assign_pointer_integer(op, arg, ltp, lt, rtp, rt)) 3001 return true; 3002 3003 if (check_assign_pointer(op, arg, ltp, lt, rtp, rt)) 3004 return true; 3005 3006 warn_assign(op, arg, ltp, lt, rtp, rt); 3007 return false; 3008 } 3009 3010 static bool 3011 has_side_effect(const tnode_t *tn) /* NOLINT(misc-no-recursion) */ 3012 { 3013 op_t op = tn->tn_op; 3014 3015 if (modtab[op].m_has_side_effect) 3016 return true; 3017 3018 if (op == CVT && tn->tn_type->t_tspec == VOID) 3019 return has_side_effect(tn->u.ops.left); 3020 3021 /* XXX: Why not has_side_effect(tn->u.ops.left) as well? */ 3022 if (op == LOGAND || op == LOGOR) 3023 return has_side_effect(tn->u.ops.right); 3024 3025 /* XXX: Why not has_side_effect(tn->u.ops.left) as well? */ 3026 if (op == QUEST) 3027 return has_side_effect(tn->u.ops.right); 3028 3029 if (op == COLON || op == COMMA) { 3030 return has_side_effect(tn->u.ops.left) || 3031 has_side_effect(tn->u.ops.right); 3032 } 3033 3034 return false; 3035 } 3036 3037 static bool 3038 is_void_cast(const tnode_t *tn) 3039 { 3040 3041 return tn->tn_op == CVT && tn->tn_cast && 3042 tn->tn_type->t_tspec == VOID; 3043 } 3044 3045 static bool 3046 is_local_symbol(const tnode_t *tn) 3047 { 3048 3049 return tn->tn_op == LOAD && 3050 tn->u.ops.left->tn_op == NAME && 3051 tn->u.ops.left->u.sym->s_scl == AUTO; 3052 } 3053 3054 static bool 3055 is_int_constant_zero(const tnode_t *tn) 3056 { 3057 3058 return tn->tn_op == CON && 3059 tn->tn_type->t_tspec == INT && 3060 tn->u.value.u.integer == 0; 3061 } 3062 3063 static void 3064 check_null_effect(const tnode_t *tn) 3065 { 3066 3067 if (hflag && 3068 !has_side_effect(tn) && 3069 !(is_void_cast(tn) && is_local_symbol(tn->u.ops.left)) && 3070 !(is_void_cast(tn) && is_int_constant_zero(tn->u.ops.left))) { 3071 /* expression has null effect */ 3072 warning(129); 3073 } 3074 } 3075 3076 /* 3077 * Check the types for specific operators and type combinations. 3078 * 3079 * At this point, the operands already conform to the type requirements of 3080 * the operator, such as being integer, floating or scalar. 3081 */ 3082 static bool 3083 typeok_op(op_t op, int arg, 3084 const tnode_t *ln, const type_t *ltp, tspec_t lt, 3085 const tnode_t *rn, const type_t *rtp, tspec_t rt) 3086 { 3087 switch (op) { 3088 case ARROW: 3089 return typeok_arrow(lt); 3090 case POINT: 3091 return typeok_point(ln, ltp, lt); 3092 case INCBEF: 3093 case DECBEF: 3094 case INCAFT: 3095 case DECAFT: 3096 return typeok_incdec(op, ln, ltp); 3097 case INDIR: 3098 return typeok_indir(ltp, lt); 3099 case ADDR: 3100 return typeok_address(op, ln, ltp, lt); 3101 case PLUS: 3102 return typeok_plus(op, ltp, lt, rtp, rt); 3103 case MINUS: 3104 return typeok_minus(op, ltp, lt, rtp, rt); 3105 case SHL: 3106 typeok_shl(op, lt, rt); 3107 goto shift; 3108 case SHR: 3109 typeok_shr(op, ln, lt, rn, rt); 3110 shift: 3111 typeok_shift(ltp, lt, rn, rt); 3112 break; 3113 case LT: 3114 case LE: 3115 case GT: 3116 case GE: 3117 compare: 3118 return typeok_compare(op, ln, ltp, lt, rn, rtp, rt); 3119 case EQ: 3120 case NE: 3121 if (is_typeok_eq(ln, lt, rn, rt)) 3122 break; 3123 goto compare; 3124 case QUEST: 3125 return typeok_quest(lt, rn); 3126 case COLON: 3127 return typeok_colon(ln, ltp, lt, rn, rtp, rt); 3128 case ASSIGN: 3129 case INIT: 3130 case FARG: 3131 case RETURN: 3132 if (!check_assign_types_compatible(op, arg, ln, rn)) 3133 return false; 3134 goto assign; 3135 case MULASS: 3136 case DIVASS: 3137 case MODASS: 3138 goto assign; 3139 case ADDASS: 3140 case SUBASS: 3141 if ((lt == PTR && !is_integer(rt)) || rt == PTR) { 3142 warn_incompatible_types(op, ltp, lt, rtp, rt); 3143 return false; 3144 } 3145 goto assign; 3146 case SHLASS: 3147 goto assign; 3148 case SHRASS: 3149 if (pflag && !is_uinteger(lt) && 3150 !(!allow_c90 && is_uinteger(rt))) { 3151 /* bitwise '%s' on signed value possibly nonportable */ 3152 warning(117, op_name(op)); 3153 } 3154 goto assign; 3155 case ANDASS: 3156 case XORASS: 3157 case ORASS: 3158 assign: 3159 return typeok_assign(op, ln, ltp, lt); 3160 case COMMA: 3161 if (!modtab[ln->tn_op].m_has_side_effect) 3162 check_null_effect(ln); 3163 break; 3164 default: 3165 break; 3166 } 3167 return true; 3168 } 3169 3170 static void 3171 check_bad_enum_operation(op_t op, const tnode_t *ln, const tnode_t *rn) 3172 { 3173 3174 if (!eflag) 3175 return; 3176 3177 /* Allow enum in array indices. */ 3178 if (op == PLUS && 3179 ((ln->tn_type->t_is_enum && rn->tn_type->t_tspec == PTR) || 3180 (rn->tn_type->t_is_enum && ln->tn_type->t_tspec == PTR))) { 3181 return; 3182 } 3183 3184 /* dubious operation '%s' on enum */ 3185 warning(241, op_name(op)); 3186 } 3187 3188 static void 3189 check_enum_type_mismatch(op_t op, int arg, const tnode_t *ln, const tnode_t *rn) 3190 { 3191 const mod_t *mp = &modtab[op]; 3192 3193 if (ln->tn_type->u.enumer != rn->tn_type->u.enumer) { 3194 switch (op) { 3195 case INIT: 3196 /* enum type mismatch between '%s' and '%s' in ... */ 3197 warning(210, 3198 type_name(ln->tn_type), type_name(rn->tn_type)); 3199 break; 3200 case FARG: 3201 /* function expects '%s', passing '%s' for arg #%d */ 3202 warning(156, 3203 type_name(ln->tn_type), type_name(rn->tn_type), 3204 arg); 3205 break; 3206 case RETURN: 3207 /* function has return type '%s' but returns '%s' */ 3208 warning(211, 3209 type_name(ln->tn_type), type_name(rn->tn_type)); 3210 break; 3211 default: 3212 /* enum type mismatch: '%s' '%s' '%s' */ 3213 warning(130, type_name(ln->tn_type), op_name(op), 3214 type_name(rn->tn_type)); 3215 break; 3216 } 3217 } else if (Pflag && eflag && mp->m_comparison && op != EQ && op != NE) 3218 /* operator '%s' assumes that '%s' is ordered */ 3219 warning(243, op_name(op), type_name(ln->tn_type)); 3220 } 3221 3222 static void 3223 check_enum_int_mismatch(op_t op, int arg, const tnode_t *ln, const tnode_t *rn) 3224 { 3225 3226 if (!eflag) 3227 return; 3228 3229 switch (op) { 3230 case INIT: 3231 /* 3232 * Initialization with 0 is allowed. Otherwise, all implicit 3233 * initializations would need to be warned upon as well. 3234 */ 3235 if (!rn->tn_type->t_is_enum && rn->tn_op == CON && 3236 is_integer(rn->tn_type->t_tspec) && 3237 rn->u.value.u.integer == 0) { 3238 return; 3239 } 3240 /* initialization of '%s' with '%s' */ 3241 warning(277, type_name(ln->tn_type), type_name(rn->tn_type)); 3242 break; 3243 case FARG: 3244 /* combination of '%s' and '%s', arg #%d */ 3245 warning(278, 3246 type_name(ln->tn_type), type_name(rn->tn_type), arg); 3247 break; 3248 case RETURN: 3249 /* combination of '%s' and '%s' in return */ 3250 warning(279, type_name(ln->tn_type), type_name(rn->tn_type)); 3251 break; 3252 default: 3253 /* combination of '%s' and '%s', op '%s' */ 3254 warning(242, type_name(ln->tn_type), type_name(rn->tn_type), 3255 op_name(op)); 3256 break; 3257 } 3258 } 3259 3260 static void 3261 typeok_enum(op_t op, const mod_t *mp, int arg, 3262 const tnode_t *ln, const type_t *ltp, 3263 const tnode_t *rn, const type_t *rtp) 3264 { 3265 if (mp->m_bad_on_enum && 3266 (ltp->t_is_enum || (mp->m_binary && rtp->t_is_enum))) { 3267 check_bad_enum_operation(op, ln, rn); 3268 } else if (mp->m_valid_on_enum && 3269 (ltp->t_is_enum && rtp != NULL && rtp->t_is_enum)) { 3270 check_enum_type_mismatch(op, arg, ln, rn); 3271 } else if (mp->m_valid_on_enum && 3272 (ltp->t_is_enum || (rtp != NULL && rtp->t_is_enum))) { 3273 check_enum_int_mismatch(op, arg, ln, rn); 3274 } 3275 } 3276 3277 /* Perform most type checks. Return whether the types are ok. */ 3278 bool 3279 typeok(op_t op, int arg, const tnode_t *ln, const tnode_t *rn) 3280 { 3281 3282 const mod_t *mp = &modtab[op]; 3283 3284 type_t *ltp = ln->tn_type; 3285 tspec_t lt = ltp->t_tspec; 3286 3287 type_t *rtp = mp->m_binary ? rn->tn_type : NULL; 3288 tspec_t rt = mp->m_binary ? rtp->t_tspec : NO_TSPEC; 3289 3290 if (Tflag && !typeok_scalar_strict_bool(op, mp, arg, ln, rn)) 3291 return false; 3292 if (!typeok_scalar(op, mp, ltp, lt, rtp, rt)) 3293 return false; 3294 3295 if (!typeok_op(op, arg, ln, ltp, lt, rn, rtp, rt)) 3296 return false; 3297 3298 typeok_enum(op, mp, arg, ln, ltp, rn, rtp); 3299 return true; 3300 } 3301 3302 /* In traditional C, keep unsigned and promote FLOAT to DOUBLE. */ 3303 static tspec_t 3304 promote_trad(tspec_t t) 3305 { 3306 3307 if (t == UCHAR || t == USHORT) 3308 return UINT; 3309 if (t == CHAR || t == SCHAR || t == SHORT) 3310 return INT; 3311 if (t == FLOAT) 3312 return DOUBLE; 3313 if (t == ENUM) 3314 return INT; 3315 return t; 3316 } 3317 3318 /* 3319 * C99 6.3.1.1p2 requires for types with lower rank than int that "If an int 3320 * can represent all the values of the original type, the value is converted 3321 * to an int; otherwise it is converted to an unsigned int", and that "All 3322 * other types are unchanged by the integer promotions". 3323 */ 3324 static tspec_t 3325 promote_c90(const tnode_t *tn, tspec_t t, bool farg) 3326 { 3327 if (tn->tn_type->t_bitfield) { 3328 unsigned int width = tn->tn_type->t_bit_field_width; 3329 unsigned int int_width = size_in_bits(INT); 3330 // XXX: What about _Bool bit-fields, since C99? 3331 if (width < int_width) 3332 return INT; 3333 if (width == int_width) 3334 return is_uinteger(t) ? UINT : INT; 3335 return t; 3336 } 3337 3338 if (t == CHAR || t == SCHAR) 3339 return INT; 3340 if (t == UCHAR) 3341 return size_in_bits(CHAR) < size_in_bits(INT) ? INT : UINT; 3342 if (t == SHORT) 3343 return INT; 3344 if (t == USHORT) 3345 return size_in_bits(SHORT) < size_in_bits(INT) ? INT : UINT; 3346 if (t == ENUM) 3347 return INT; 3348 if (farg && t == FLOAT) 3349 return DOUBLE; 3350 return t; 3351 } 3352 3353 /* 3354 * Performs the "integer promotions" (C99 6.3.1.1p2), which convert small 3355 * integer types to either int or unsigned int. 3356 * 3357 * If allow_c90 is unset or the operand is a function argument with no type 3358 * information (no prototype or variable # of args), converts float to double. 3359 */ 3360 tnode_t * 3361 promote(op_t op, bool farg, tnode_t *tn) 3362 { 3363 3364 const type_t *otp = tn->tn_type; 3365 tspec_t ot = otp->t_tspec; 3366 if (!is_arithmetic(ot)) 3367 return tn; 3368 3369 tspec_t nt = allow_c90 ? promote_c90(tn, ot, farg) : promote_trad(ot); 3370 if (nt == ot) 3371 return tn; 3372 3373 type_t *ntp = expr_dup_type(gettyp(nt)); 3374 ntp->t_tspec = nt; 3375 ntp->t_is_enum = otp->t_is_enum; 3376 if (ntp->t_is_enum) 3377 ntp->u.enumer = otp->u.enumer; 3378 ntp->t_bitfield = otp->t_bitfield; 3379 if (ntp->t_bitfield) { 3380 ntp->t_bit_field_width = otp->t_bit_field_width; 3381 ntp->t_bit_field_offset = otp->t_bit_field_offset; 3382 } 3383 if (ntp->t_bitfield && is_uinteger(ot) && !is_uinteger(nt)) 3384 ntp->t_bit_field_width++; 3385 return convert(op, 0, ntp, tn); 3386 } 3387 3388 static void 3389 check_lossy_floating_to_integer_conversion( 3390 op_t op, int arg, const type_t *tp, const tnode_t *tn) 3391 { 3392 long double x = tn->u.value.u.floating; 3393 integer_constraints ic = ic_any(tp); 3394 if (is_uinteger(tp->t_tspec) 3395 ? x >= ic.umin && x <= ic.umax && x == (uint64_t)x 3396 : x >= ic.smin && x <= ic.smax && x == (int64_t)x) 3397 return; 3398 if (op == FARG) 3399 /* lossy conversion of %Lg to '%s', arg #%d */ 3400 warning(380, x, type_name(tp), arg); 3401 else 3402 /* lossy conversion of %Lg to '%s' */ 3403 warning(381, x, type_name(tp)); 3404 } 3405 3406 static void 3407 convert_integer_from_floating( 3408 op_t op, int arg, const type_t *tp, const tnode_t *tn) 3409 { 3410 3411 if (op == CVT) 3412 /* cast from floating point '%s' to integer '%s' */ 3413 query_message(2, type_name(tn->tn_type), type_name(tp)); 3414 else 3415 /* implicit conversion from floating point '%s' to ... */ 3416 query_message(1, type_name(tn->tn_type), type_name(tp)); 3417 if (tn->tn_op == CON) 3418 check_lossy_floating_to_integer_conversion(op, arg, tp, tn); 3419 } 3420 3421 static bool 3422 should_warn_about_prototype_conversion(tspec_t nt, 3423 tspec_t ot, const tnode_t *ptn) 3424 { 3425 3426 if (nt == ot) 3427 return false; 3428 3429 if (nt == ENUM && ot == INT) 3430 return false; 3431 3432 if (is_floating(nt) != is_floating(ot) || 3433 portable_rank_cmp(nt, ot) != 0) { 3434 /* representation and/or width change */ 3435 if (!is_integer(ot)) 3436 return true; 3437 /* 3438 * XXX: Investigate whether this rule makes sense; see 3439 * tests/usr.bin/xlint/lint1/platform_long.c. 3440 */ 3441 return portable_rank_cmp(ot, INT) > 0; 3442 } 3443 3444 if (!hflag) 3445 return false; 3446 3447 /* 3448 * If the types differ only in sign and the argument has the same 3449 * representation in both types, print no warning. 3450 */ 3451 if (ptn->tn_op == CON && is_integer(nt) && 3452 signed_type(nt) == signed_type(ot) && 3453 !msb(ptn->u.value.u.integer, ot)) 3454 return false; 3455 3456 return true; 3457 } 3458 3459 /* 3460 * Warn if a prototype causes a type conversion that is different from what 3461 * would happen to the same argument in the absence of a prototype. This 3462 * check is intended for code that needs to stay compatible with pre-C90 C. 3463 * 3464 * Errors/warnings about illegal type combinations are already printed 3465 * in check_assign_types_compatible(). 3466 */ 3467 static void 3468 check_prototype_conversion(int arg, tspec_t nt, tspec_t ot, type_t *tp, 3469 tnode_t *tn) 3470 { 3471 3472 if (!is_arithmetic(nt) || !is_arithmetic(ot)) 3473 return; 3474 3475 /* 3476 * If the type of the formal parameter is char/short, a warning would 3477 * be useless, because functions declared the old style can't expect 3478 * char/short arguments. 3479 */ 3480 if (nt == CHAR || nt == SCHAR || nt == UCHAR || 3481 nt == SHORT || nt == USHORT) 3482 return; 3483 3484 tnode_t *ptn = promote(NOOP, true, tn); 3485 ot = ptn->tn_type->t_tspec; 3486 3487 if (should_warn_about_prototype_conversion(nt, ot, ptn)) { 3488 /* argument %d is converted from '%s' to '%s' ... */ 3489 warning(259, arg, type_name(tn->tn_type), type_name(tp)); 3490 } 3491 } 3492 3493 /* 3494 * When converting a large integer type to a small integer type, in some 3495 * cases the value of the actual expression is further restricted than the 3496 * type bounds, such as in (expr & 0xFF) or (expr % 100) or (expr >> 24). 3497 */ 3498 static bool 3499 can_represent(const type_t *tp, const tnode_t *tn) 3500 { 3501 uint64_t nmask = value_bits(width_in_bits(tp)); 3502 if (!is_uinteger(tp->t_tspec)) 3503 nmask >>= 1; 3504 3505 integer_constraints c = ic_expr(tn); 3506 if ((~c.bclr & ~nmask) == 0) 3507 return true; 3508 3509 integer_constraints tpc = ic_any(tp); 3510 if (is_uinteger(tp->t_tspec) 3511 ? tpc.umin <= c.umin && tpc.umax >= c.umax 3512 : tpc.smin <= c.smin && tpc.smax >= c.smax) 3513 return true; 3514 3515 debug_enter(); 3516 debug_step("type '%s' cannot represent:", type_name(tp)); 3517 debug_node(tn); 3518 debug_leave(); 3519 return false; 3520 } 3521 3522 static bool 3523 should_warn_about_integer_conversion(const type_t *ntp, tspec_t nt, 3524 const tnode_t *otn, tspec_t ot) 3525 { 3526 3527 // XXX: The portable_rank_cmp aims at portable mode, independent of the 3528 // current platform, while can_represent acts on the actual type sizes 3529 // from the current platform. This mix is inconsistent, but anything 3530 // else would make the exact conditions too complicated to grasp. 3531 if (aflag > 0 && portable_rank_cmp(nt, ot) < 0) { 3532 if (ot == LONG || ot == ULONG 3533 || ot == LLONG || ot == ULLONG 3534 #ifdef INT128_SIZE 3535 || ot == INT128 || ot == UINT128 3536 #endif 3537 || aflag > 1) 3538 return !can_represent(ntp, otn); 3539 } 3540 return false; 3541 } 3542 3543 static void 3544 convert_integer_from_integer(op_t op, int arg, tspec_t nt, tspec_t ot, 3545 type_t *tp, tnode_t *tn) 3546 { 3547 3548 if (tn->tn_op == CON) 3549 return; 3550 3551 if (op == CVT) 3552 return; 3553 3554 if (Pflag && pflag && aflag > 0 && 3555 portable_rank_cmp(nt, ot) > 0 && 3556 is_uinteger(nt) != is_uinteger(ot)) { 3557 if (op == FARG) 3558 /* conversion to '%s' may sign-extend ... */ 3559 warning(297, type_name(tp), arg); 3560 else 3561 /* conversion to '%s' may sign-extend ... */ 3562 warning(131, type_name(tp)); 3563 } 3564 3565 if (Pflag && portable_rank_cmp(nt, ot) > 0 && 3566 (tn->tn_op == PLUS || tn->tn_op == MINUS || tn->tn_op == MULT || 3567 tn->tn_op == SHL)) { 3568 /* suggest cast from '%s' to '%s' on op '%s' to ... */ 3569 warning(324, type_name(gettyp(ot)), type_name(tp), 3570 op_name(tn->tn_op)); 3571 } 3572 3573 if (should_warn_about_integer_conversion(tp, nt, tn, ot)) { 3574 if (op == FARG) { 3575 /* conversion from '%s' to '%s' may lose ... */ 3576 warning(298, 3577 type_name(tn->tn_type), type_name(tp), arg); 3578 } else { 3579 /* conversion from '%s' to '%s' may lose accuracy */ 3580 warning(132, 3581 type_name(tn->tn_type), type_name(tp)); 3582 } 3583 } 3584 3585 if (any_query_enabled && is_uinteger(nt) != is_uinteger(ot)) 3586 /* implicit conversion changes sign from '%s' to '%s' */ 3587 query_message(3, type_name(tn->tn_type), type_name(tp)); 3588 } 3589 3590 static void 3591 convert_integer_from_pointer(op_t op, tspec_t nt, type_t *tp, tnode_t *tn) 3592 { 3593 3594 if (tn->tn_op == CON) 3595 return; 3596 if (op != CVT) 3597 return; /* We already got an error. */ 3598 if (portable_rank_cmp(nt, PTR) >= 0) 3599 return; 3600 3601 if (pflag && size_in_bits(nt) >= size_in_bits(PTR)) { 3602 /* conversion of pointer to '%s' may lose bits */ 3603 warning(134, type_name(tp)); 3604 } else { 3605 /* conversion of pointer to '%s' loses bits */ 3606 warning(133, type_name(tp)); 3607 } 3608 } 3609 3610 static bool 3611 struct_starts_with(const type_t *struct_tp, const type_t *member_tp) 3612 { 3613 3614 return struct_tp->u.sou->sou_first_member != NULL && 3615 types_compatible(struct_tp->u.sou->sou_first_member->s_type, 3616 member_tp, true, false, NULL); 3617 } 3618 3619 static bool 3620 is_byte_array(const type_t *tp) 3621 { 3622 3623 return tp->t_tspec == ARRAY && 3624 (tp->t_subt->t_tspec == CHAR || tp->t_subt->t_tspec == UCHAR); 3625 } 3626 3627 static bool 3628 union_contains(const type_t *utp, const type_t *mtp) 3629 { 3630 for (const sym_t *mem = utp->u.sou->sou_first_member; 3631 mem != NULL; mem = mem->s_next) { 3632 if (types_compatible(mem->s_type, mtp, true, false, NULL)) 3633 return true; 3634 } 3635 return false; 3636 } 3637 3638 static bool 3639 should_warn_about_pointer_cast(const type_t *nstp, tspec_t nst, 3640 const type_t *ostp, tspec_t ost) 3641 { 3642 3643 while (nst == ARRAY) 3644 nstp = nstp->t_subt, nst = nstp->t_tspec; 3645 while (ost == ARRAY) 3646 ostp = ostp->t_subt, ost = ostp->t_tspec; 3647 3648 if (nst == STRUCT && ost == STRUCT && 3649 (struct_starts_with(nstp, ostp) || 3650 struct_starts_with(ostp, nstp))) 3651 return false; 3652 3653 if (is_incomplete(nstp) || is_incomplete(ostp)) 3654 return false; 3655 3656 if (nst == CHAR || nst == UCHAR) 3657 return false; /* for the sake of traditional C code */ 3658 if (ost == CHAR || ost == UCHAR) 3659 return false; /* for the sake of traditional C code */ 3660 3661 /* Allow cast between pointers to sockaddr variants. */ 3662 if (nst == STRUCT && ost == STRUCT) { 3663 const sym_t *nmem = nstp->u.sou->sou_first_member; 3664 const sym_t *omem = ostp->u.sou->sou_first_member; 3665 while (nmem != NULL && omem != NULL && 3666 types_compatible(nmem->s_type, omem->s_type, 3667 true, false, NULL)) 3668 nmem = nmem->s_next, omem = omem->s_next; 3669 if (nmem != NULL && is_byte_array(nmem->s_type)) 3670 return false; 3671 if (omem != NULL && is_byte_array(omem->s_type)) 3672 return false; 3673 if (nmem == NULL && omem == NULL) 3674 return false; 3675 } 3676 3677 if (nst == UNION || ost == UNION) { 3678 const type_t *union_tp = nst == UNION ? nstp : ostp; 3679 const type_t *other_tp = nst == UNION ? ostp : nstp; 3680 if (union_contains(union_tp, other_tp)) 3681 return false; 3682 } 3683 3684 if (is_struct_or_union(nst) && is_struct_or_union(ost)) 3685 return nstp->u.sou != ostp->u.sou; 3686 3687 enum rank_kind rk1 = type_properties(nst)->tt_rank_kind; 3688 enum rank_kind rk2 = type_properties(ost)->tt_rank_kind; 3689 if (rk1 != rk2 || rk1 == RK_NONE) 3690 return true; 3691 3692 return portable_rank_cmp(nst, ost) != 0; 3693 } 3694 3695 static void 3696 convert_pointer_from_pointer(type_t *ntp, tnode_t *tn) 3697 { 3698 const type_t *nstp = ntp->t_subt; 3699 const type_t *otp = tn->tn_type; 3700 const type_t *ostp = otp->t_subt; 3701 tspec_t nst = nstp->t_tspec; 3702 tspec_t ost = ostp->t_tspec; 3703 3704 if (nst == VOID || ost == VOID) { 3705 /* TODO: C99 behaves like C90 here. */ 3706 if (!allow_trad && !allow_c99 && (nst == FUNC || ost == FUNC)) { 3707 const char *nts, *ots; 3708 /* null pointers are already handled in convert() */ 3709 *(nst == FUNC ? &nts : &ots) = "function pointer"; 3710 *(nst == VOID ? &nts : &ots) = "'void *'"; 3711 /* conversion of %s to %s requires a cast */ 3712 warning(303, ots, nts); 3713 } 3714 return; 3715 } 3716 if (nst == FUNC && ost == FUNC) 3717 return; 3718 if (nst == FUNC || ost == FUNC) { 3719 /* converting '%s' to '%s' is questionable */ 3720 warning(229, type_name(otp), type_name(ntp)); 3721 return; 3722 } 3723 3724 if (hflag && alignment(nstp) > alignment(ostp) && 3725 ost != CHAR && ost != UCHAR && 3726 !is_incomplete(ostp) && 3727 !(nst == UNION && union_contains(nstp, ostp))) { 3728 /* converting '%s' to '%s' increases alignment ... */ 3729 warning(135, type_name(otp), type_name(ntp), 3730 alignment(ostp), alignment(nstp)); 3731 } 3732 3733 if (cflag && should_warn_about_pointer_cast(nstp, nst, ostp, ost)) { 3734 /* pointer cast from '%s' to unrelated '%s' */ 3735 warning(247, type_name(ostp), type_name(nstp)); 3736 } 3737 } 3738 3739 /* 3740 * Insert a conversion operator, which converts the type of the node 3741 * to another given type. 3742 * 3743 * Possible values for 'op': 3744 * CVT a cast-expression 3745 * binary integer promotion for one of the operands, or a usual 3746 * arithmetic conversion 3747 * binary plain or compound assignments to bit-fields 3748 * FARG 'arg' is the number of the parameter (used for warnings) 3749 * NOOP several other implicit conversions 3750 * ... 3751 */ 3752 tnode_t * 3753 convert(op_t op, int arg, type_t *tp, tnode_t *tn) 3754 { 3755 tspec_t nt = tp->t_tspec; 3756 tspec_t ot = tn->tn_type->t_tspec; 3757 3758 if (allow_trad && allow_c90 && op == FARG) 3759 check_prototype_conversion(arg, nt, ot, tp, tn); 3760 3761 if (nt == BOOL) { 3762 /* No further checks. */ 3763 3764 } else if (is_integer(nt)) { 3765 if (ot == BOOL) { 3766 /* No further checks. */ 3767 } else if (is_integer(ot)) 3768 convert_integer_from_integer(op, arg, nt, ot, tp, tn); 3769 else if (is_floating(ot)) 3770 convert_integer_from_floating(op, arg, tp, tn); 3771 else if (ot == PTR) 3772 convert_integer_from_pointer(op, nt, tp, tn); 3773 3774 } else if (is_floating(nt)) { 3775 if (is_integer(ot) && op != CVT) { 3776 /* implicit conversion from integer '%s' to ... */ 3777 query_message(19, 3778 type_name(tn->tn_type), type_name(tp)); 3779 } 3780 3781 } else if (nt == PTR) { 3782 if (is_null_pointer(tn)) { 3783 /* a null pointer may be assigned to any pointer. */ 3784 } else if (ot == PTR && op == CVT) 3785 convert_pointer_from_pointer(tp, tn); 3786 } 3787 3788 tnode_t *ntn = expr_alloc_tnode(); 3789 ntn->tn_op = CVT; 3790 ntn->tn_type = tp; 3791 ntn->tn_cast = op == CVT; 3792 ntn->tn_sys |= tn->tn_sys; 3793 ntn->u.ops.right = NULL; 3794 if (tn->tn_op != CON || nt == VOID) { 3795 ntn->u.ops.left = tn; 3796 } else { 3797 ntn->tn_op = CON; 3798 convert_constant(op, arg, ntn->tn_type, &ntn->u.value, 3799 &tn->u.value); 3800 } 3801 3802 return ntn; 3803 } 3804 3805 static void 3806 convert_constant_from_floating(op_t op, int arg, const type_t *ntp, 3807 tspec_t nt, val_t *nv, val_t *ov) 3808 { 3809 long double max = 0.0, min = 0.0; 3810 3811 switch (nt) { 3812 case CHAR: 3813 max = TARG_CHAR_MAX; min = TARG_CHAR_MIN; break; 3814 case UCHAR: 3815 max = TARG_UCHAR_MAX; min = 0; break; 3816 case SCHAR: 3817 max = TARG_SCHAR_MAX; min = TARG_SCHAR_MIN; break; 3818 case SHORT: 3819 max = TARG_SHRT_MAX; min = TARG_SHRT_MIN; break; 3820 case USHORT: 3821 max = TARG_USHRT_MAX; min = 0; break; 3822 case ENUM: 3823 case INT: 3824 max = TARG_INT_MAX; min = TARG_INT_MIN; break; 3825 case UINT: 3826 max = TARG_UINT_MAX; min = 0; break; 3827 case LONG: 3828 max = TARG_LONG_MAX; min = TARG_LONG_MIN; break; 3829 case ULONG: 3830 max = TARG_ULONG_MAX; min = 0; break; 3831 case LLONG: 3832 max = LLONG_MAX; min = LLONG_MIN; break; 3833 case ULLONG: 3834 max = ULLONG_MAX; min = 0; break; 3835 case FLOAT: 3836 case FCOMPLEX: 3837 max = FLT_MAX; min = -FLT_MAX; break; 3838 case DOUBLE: 3839 case DCOMPLEX: 3840 max = DBL_MAX; min = -DBL_MAX; break; 3841 case LDOUBLE: 3842 case LCOMPLEX: 3843 /* LINTED 248; see floating_error_value. */ 3844 max = LDBL_MAX; min = -max; break; 3845 default: 3846 lint_assert(/*CONSTCOND*/false); 3847 } 3848 if (ov->u.floating > max || ov->u.floating < min) { 3849 lint_assert(nt != LDOUBLE); 3850 const char *ot_name = type_name(gettyp(ov->v_tspec)); 3851 const char *nt_name = type_name(ntp); 3852 if (is_integer(nt)) 3853 goto after_warning; 3854 if (op == FARG) 3855 /* conversion of '%s' to '%s' is out of range, ... */ 3856 warning(295, ot_name, nt_name, arg); 3857 else 3858 /* conversion of '%s' to '%s' is out of range */ 3859 warning(119, ot_name, nt_name); 3860 after_warning: 3861 ov->u.floating = ov->u.floating > 0 ? max : min; 3862 } 3863 3864 if (nt == FLOAT || nt == FCOMPLEX) 3865 nv->u.floating = (float)ov->u.floating; 3866 else if (nt == DOUBLE || nt == DCOMPLEX) 3867 nv->u.floating = (double)ov->u.floating; 3868 else if (nt == LDOUBLE || nt == LCOMPLEX) 3869 nv->u.floating = ov->u.floating; 3870 else 3871 nv->u.integer = (int64_t)ov->u.floating; 3872 } 3873 3874 static bool 3875 convert_constant_to_floating(tspec_t nt, val_t *nv, 3876 tspec_t ot, const val_t *v) 3877 { 3878 if (nt == FLOAT) { 3879 nv->u.floating = (ot == PTR || is_uinteger(ot)) ? 3880 (float)(uint64_t)v->u.integer : (float)v->u.integer; 3881 } else if (nt == DOUBLE) { 3882 nv->u.floating = (ot == PTR || is_uinteger(ot)) ? 3883 (double)(uint64_t)v->u.integer : (double)v->u.integer; 3884 } else if (nt == LDOUBLE) { 3885 nv->u.floating = (ot == PTR || is_uinteger(ot)) 3886 ? (long double)(uint64_t)v->u.integer 3887 : (long double)v->u.integer; 3888 } else 3889 return false; 3890 return true; 3891 } 3892 3893 /* 3894 * Print a warning if bits which were set are lost due to the conversion. 3895 * This can happen with operator ORASS only. 3896 */ 3897 static void 3898 convert_constant_check_range_bitor(size_t nsz, size_t osz, const val_t *v, 3899 uint64_t xmask, op_t op) 3900 { 3901 if (nsz < osz && (v->u.integer & xmask) != 0) 3902 /* constant truncated by conversion, op '%s' */ 3903 warning(306, op_name(op)); 3904 } 3905 3906 static void 3907 convert_constant_check_range_bitand(size_t nsz, size_t osz, 3908 uint64_t xmask, const val_t *nv, 3909 tspec_t ot, const val_t *v, 3910 const type_t *tp, op_t op) 3911 { 3912 if (nsz > osz && 3913 (nv->u.integer & bit((unsigned int)(osz - 1))) != 0 && 3914 (nv->u.integer & xmask) != xmask) { 3915 /* extra bits set to 0 in conversion of '%s' to '%s', ... */ 3916 warning(309, type_name(gettyp(ot)), 3917 type_name(tp), op_name(op)); 3918 } else if (nsz < osz && 3919 (v->u.integer & xmask) != xmask && 3920 (v->u.integer & xmask) != 0) 3921 /* constant truncated by conversion, op '%s' */ 3922 warning(306, op_name(op)); 3923 } 3924 3925 static void 3926 convert_constant_check_range_signed(op_t op, int arg, 3927 const type_t *ntp, int64_t ov) 3928 { 3929 if (op == ASSIGN) 3930 /* assignment of negative constant %lld to unsigned ... */ 3931 warning(164, (long long)ov, type_name(ntp)); 3932 else if (op == INIT) 3933 /* initialization of unsigned type '%s' with negative ... */ 3934 warning(221, type_name(ntp), (long long)ov); 3935 else if (op == FARG) 3936 /* conversion of negative constant %lld to unsigned ... */ 3937 warning(296, (long long)ov, type_name(ntp), arg); 3938 else if (modtab[op].m_comparison) { 3939 /* handled by check_integer_comparison() */ 3940 } else 3941 /* conversion of negative constant %lld to unsigned ... */ 3942 warning(222, (long long)ov, type_name(ntp)); 3943 } 3944 3945 /* 3946 * Loss of significant bit(s). All truncated bits of unsigned types or all 3947 * truncated bits plus the msb of the target for signed types are considered 3948 * to be significant bits. Loss of significant bits means that at least one 3949 * of the bits was set in an unsigned type or that at least one but not all 3950 * of the bits was set in a signed type. Loss of significant bits means that 3951 * it is not possible, also not with necessary casts, to convert back to the 3952 * original type. An example for a necessary cast is: 3953 * char c; int i; c = 128; 3954 * i = c; ** yields -128 ** 3955 * i = (unsigned char)c; ** yields 128 ** 3956 */ 3957 static void 3958 warn_constant_check_range_truncated(op_t op, int arg, const type_t *tp, 3959 tspec_t ot) 3960 { 3961 if (op == ASSIGN && tp->t_bitfield) 3962 /* precision lost in bit-field assignment */ 3963 warning(166); 3964 else if (op == ASSIGN) 3965 /* constant truncated by assignment */ 3966 warning(165); 3967 else if (op == INIT && tp->t_bitfield) 3968 /* bit-field initializer does not fit */ 3969 warning(180); 3970 else if (op == INIT) 3971 /* initializer does not fit */ 3972 warning(178); 3973 else if (op == CASE) 3974 /* case label affected by conversion */ 3975 warning(196); 3976 else if (op == FARG) 3977 /* conversion of '%s' to '%s' is out of range, arg #%d */ 3978 warning(295, type_name(gettyp(ot)), type_name(tp), arg); 3979 else 3980 /* conversion of '%s' to '%s' is out of range */ 3981 warning(119, type_name(gettyp(ot)), type_name(tp)); 3982 } 3983 3984 static void 3985 warn_constant_check_range_loss(op_t op, int arg, const type_t *tp, 3986 tspec_t ot) 3987 { 3988 if (op == ASSIGN && tp->t_bitfield) 3989 /* precision lost in bit-field assignment */ 3990 warning(166); 3991 else if (op == INIT && tp->t_bitfield) 3992 /* bit-field initializer out of range */ 3993 warning(11); 3994 else if (op == CASE) 3995 /* case label affected by conversion */ 3996 warning(196); 3997 else if (op == FARG) 3998 /* conversion of '%s' to '%s' is out of range, arg #%d */ 3999 warning(295, type_name(gettyp(ot)), type_name(tp), arg); 4000 else 4001 /* conversion of '%s' to '%s' is out of range */ 4002 warning(119, type_name(gettyp(ot)), type_name(tp)); 4003 } 4004 4005 static void 4006 convert_constant_check_range(tspec_t ot, const type_t *tp, tspec_t nt, 4007 op_t op, int arg, const val_t *v, val_t *nv) 4008 { 4009 unsigned int obitsz, nbitsz; 4010 uint64_t xmask, xmsk1; 4011 4012 obitsz = size_in_bits(ot); 4013 nbitsz = tp->t_bitfield ? tp->t_bit_field_width : size_in_bits(nt); 4014 xmask = value_bits(nbitsz) ^ value_bits(obitsz); 4015 xmsk1 = value_bits(nbitsz) ^ value_bits(obitsz - 1); 4016 if (op == ORASS || op == BITOR || op == BITXOR) { 4017 convert_constant_check_range_bitor( 4018 nbitsz, obitsz, v, xmask, op); 4019 } else if (op == ANDASS || op == BITAND) { 4020 convert_constant_check_range_bitand( 4021 nbitsz, obitsz, xmask, nv, ot, v, tp, op); 4022 } else if (nt != PTR && is_uinteger(nt) && 4023 ot != PTR && !is_uinteger(ot) && 4024 v->u.integer < 0) 4025 convert_constant_check_range_signed(op, arg, 4026 tp, v->u.integer); 4027 else if (nv->u.integer != v->u.integer && nbitsz <= obitsz && 4028 (v->u.integer & xmask) != 0 && 4029 (is_uinteger(ot) || (v->u.integer & xmsk1) != xmsk1)) 4030 warn_constant_check_range_truncated(op, arg, tp, ot); 4031 else if (nv->u.integer != v->u.integer) 4032 warn_constant_check_range_loss(op, arg, tp, ot); 4033 } 4034 4035 /* Converts a typed constant to a constant of another type. */ 4036 void 4037 convert_constant(op_t op, int arg, const type_t *ntp, val_t *nv, val_t *ov) 4038 { 4039 /* 4040 * TODO: make 'ov' const; the name of this function does not suggest 4041 * that it modifies 'ov'. 4042 */ 4043 tspec_t ot = ov->v_tspec; 4044 tspec_t nt = nv->v_tspec = ntp->t_tspec; 4045 bool range_check = false; 4046 4047 if (nt == BOOL) { /* C99 6.3.1.2 */ 4048 nv->v_unsigned_since_c90 = false; 4049 nv->u.integer = is_nonzero_val(ov) ? 1 : 0; 4050 return; 4051 } 4052 4053 if (ot == FLOAT || ot == DOUBLE || ot == LDOUBLE) 4054 convert_constant_from_floating(op, arg, ntp, nt, nv, ov); 4055 else if (!convert_constant_to_floating(nt, nv, ot, ov)) { 4056 range_check = true; /* Check for lost precision. */ 4057 nv->u.integer = ov->u.integer; 4058 } 4059 4060 if (allow_trad && allow_c90 && ov->v_unsigned_since_c90 && 4061 (is_floating(nt) || ( 4062 (is_integer(nt) && !is_uinteger(nt) && 4063 portable_rank_cmp(nt, ot) > 0)))) { 4064 /* C90 treats constant as unsigned */ 4065 warning(157); 4066 ov->v_unsigned_since_c90 = false; 4067 } 4068 4069 if (is_integer(nt)) { 4070 unsigned int size = ntp->t_bitfield 4071 ? ntp->t_bit_field_width : size_in_bits(nt); 4072 nv->u.integer = convert_integer(nv->u.integer, nt, size); 4073 } 4074 4075 if (range_check && op != CVT) 4076 convert_constant_check_range(ot, ntp, nt, op, arg, ov, nv); 4077 } 4078 4079 tnode_t * 4080 build_sizeof(const type_t *tp) 4081 { 4082 unsigned int size_in_bytes = type_size_in_bits(tp) / CHAR_SIZE; 4083 tnode_t *tn = build_integer_constant(SIZEOF_TSPEC, size_in_bytes); 4084 tn->tn_system_dependent = true; 4085 debug_step("build_sizeof '%s' = %u", type_name(tp), size_in_bytes); 4086 return tn; 4087 } 4088 4089 tnode_t * 4090 build_offsetof(const type_t *tp, designation dn) 4091 { 4092 unsigned int offset_in_bits = 0; 4093 4094 if (!is_struct_or_union(tp->t_tspec)) { 4095 /* unacceptable operand of '%s' */ 4096 error(111, "offsetof"); 4097 goto proceed; 4098 } 4099 for (size_t i = 0; i < dn.dn_len; i++) { 4100 const designator *dr = dn.dn_items + i; 4101 if (dr->dr_kind == DK_SUBSCRIPT) { 4102 if (tp->t_tspec != ARRAY) 4103 goto proceed; /* silent error */ 4104 tp = tp->t_subt; 4105 offset_in_bits += (unsigned) dr->dr_subscript 4106 * type_size_in_bits(tp); 4107 } else { 4108 if (!is_struct_or_union(tp->t_tspec)) 4109 goto proceed; /* silent error */ 4110 const char *name = dr->dr_member->s_name; 4111 sym_t *mem = find_member(tp->u.sou, name); 4112 if (mem == NULL) { 4113 /* type '%s' does not have member '%s' */ 4114 error(101, name, type_name(tp)); 4115 goto proceed; 4116 } 4117 tp = mem->s_type; 4118 offset_in_bits += mem->u.s_member.sm_offset_in_bits; 4119 } 4120 } 4121 free(dn.dn_items); 4122 4123 proceed:; 4124 unsigned int offset_in_bytes = offset_in_bits / CHAR_SIZE; 4125 tnode_t *tn = build_integer_constant(SIZEOF_TSPEC, offset_in_bytes); 4126 tn->tn_system_dependent = true; 4127 return tn; 4128 } 4129 4130 unsigned int 4131 type_size_in_bits(const type_t *tp) 4132 { 4133 4134 unsigned int elem = 1; 4135 bool flex = false; 4136 lint_assert(tp != NULL); 4137 while (tp->t_tspec == ARRAY) { 4138 flex = true; /* allow c99 flex arrays [] [0] */ 4139 elem *= tp->u.dimension; 4140 tp = tp->t_subt; 4141 } 4142 if (elem == 0 && !flex) { 4143 /* cannot take size/alignment of incomplete type */ 4144 error(143); 4145 elem = 1; 4146 } 4147 4148 unsigned int elsz; 4149 switch (tp->t_tspec) { 4150 case VOID: 4151 /* cannot take size/alignment of void */ 4152 error(146); 4153 elsz = 1; 4154 break; 4155 case FUNC: 4156 /* cannot take size/alignment of function type '%s' */ 4157 error(144, type_name(tp)); 4158 elsz = 1; 4159 break; 4160 case STRUCT: 4161 case UNION: 4162 if (is_incomplete(tp)) { 4163 /* cannot take size/alignment of incomplete type */ 4164 error(143); 4165 elsz = 1; 4166 } else 4167 elsz = tp->u.sou->sou_size_in_bits; 4168 break; 4169 case ENUM: 4170 if (is_incomplete(tp)) { 4171 /* cannot take size/alignment of incomplete type */ 4172 warning(143); 4173 } 4174 /* FALLTHROUGH */ 4175 default: 4176 if (tp->t_bitfield) 4177 /* cannot take size/alignment of bit-field */ 4178 error(145); 4179 elsz = size_in_bits(tp->t_tspec); 4180 lint_assert(elsz > 0); 4181 break; 4182 } 4183 4184 return elem * elsz; 4185 } 4186 4187 /* C11 6.5.3.4, GCC */ 4188 tnode_t * 4189 build_alignof(const type_t *tp) 4190 { 4191 if (tp->t_tspec == FUNC) { 4192 /* cannot take size/alignment of function type '%s' */ 4193 error(144, type_name(tp)); 4194 return NULL; 4195 } 4196 if (tp->t_tspec == VOID) { 4197 /* cannot take size/alignment of void */ 4198 error(146); 4199 return NULL; 4200 } 4201 if (is_incomplete(tp)) { 4202 /* cannot take size/alignment of incomplete type */ 4203 error(143); 4204 return NULL; 4205 } 4206 if (tp->t_bitfield) { 4207 /* cannot take size/alignment of bit-field */ 4208 error(145); 4209 return NULL; 4210 } 4211 return build_integer_constant(SIZEOF_TSPEC, (int64_t)alignment(tp)); 4212 } 4213 4214 static tnode_t * 4215 cast_to_union(tnode_t *otn, bool sys, type_t *ntp) 4216 { 4217 4218 if (!allow_gcc) { 4219 /* union cast is a GCC extension */ 4220 error(328); 4221 return NULL; 4222 } 4223 4224 for (const sym_t *m = ntp->u.sou->sou_first_member; 4225 m != NULL; m = m->s_next) { 4226 if (types_compatible(m->s_type, otn->tn_type, 4227 false, false, NULL)) { 4228 tnode_t *ntn = build_op(CVT, sys, ntp, otn, NULL); 4229 ntn->tn_cast = true; 4230 return ntn; 4231 } 4232 } 4233 4234 /* type '%s' is not a member of '%s' */ 4235 error(329, type_name(otn->tn_type), type_name(ntp)); 4236 return NULL; 4237 } 4238 4239 // In GCC mode, allow 'nullptr + offset' as a constant expression. 4240 static tnode_t * 4241 null_pointer_offset(tnode_t *tn) 4242 { 4243 uint64_t off = 0; 4244 const tnode_t *n = tn; 4245 while ((n->tn_op == PLUS || n->tn_op == MINUS) 4246 && is_integer(n->u.ops.right->tn_type->t_tspec)) { 4247 off += (uint64_t)n->u.ops.right->u.value.u.integer; 4248 n = n->u.ops.left; 4249 } 4250 if (n->tn_type->t_tspec == PTR 4251 && n->tn_op == ADDR 4252 && n->u.ops.left->tn_op == INDIR 4253 && n->u.ops.left->u.ops.left->tn_op == CON 4254 && n->u.ops.left->u.ops.left->tn_type->t_tspec == PTR) { 4255 off += (uint64_t)n->u.ops.left->u.ops.left->u.value.u.integer; 4256 return build_integer_constant(SIZEOF_TSPEC, (int64_t)off); 4257 } 4258 return tn; 4259 } 4260 4261 tnode_t * 4262 cast(tnode_t *tn, bool sys, type_t *tp) 4263 { 4264 4265 if (tn == NULL) 4266 return NULL; 4267 4268 tn = cconv(tn); 4269 4270 lint_assert(tp != NULL); 4271 tspec_t nt = tp->t_tspec; 4272 tspec_t ot = tn->tn_type->t_tspec; 4273 4274 if (nt == VOID) { 4275 /* 4276 * C90 6.3.4, C99 6.5.4p2 and C11 6.5.4p2 allow any type to be 4277 * cast to void. The only other allowed casts are from a 4278 * scalar type to a scalar type. 4279 */ 4280 } else if (nt == UNION) 4281 return cast_to_union(tn, sys, tp); 4282 else if (nt == STRUCT || nt == ARRAY || nt == FUNC) { 4283 /* Casting to a struct is an undocumented GCC extension. */ 4284 if (!(allow_gcc && nt == STRUCT)) 4285 goto invalid_cast; 4286 } else if (is_struct_or_union(ot)) 4287 goto invalid_cast; 4288 else if (ot == VOID) { 4289 /* improper cast of void expression */ 4290 error(148); 4291 return NULL; 4292 } else if (is_integer(nt) && is_scalar(ot)) { 4293 tn = null_pointer_offset(tn); 4294 } else if (is_floating(nt) && is_arithmetic(ot)) { 4295 /* ok */ 4296 } else if (nt == PTR && is_integer(ot)) { 4297 /* ok */ 4298 } else if (nt == PTR && ot == PTR) { 4299 if (!tp->t_subt->t_const && tn->tn_type->t_subt->t_const) { 4300 if (hflag) 4301 /* cast discards 'const' from type '%s' */ 4302 warning(275, type_name(tn->tn_type)); 4303 } 4304 } else 4305 goto invalid_cast; 4306 4307 if (any_query_enabled 4308 && types_compatible(tp, tn->tn_type, false, false, NULL)) 4309 /* no-op cast from '%s' to '%s' */ 4310 query_message(6, type_name(tn->tn_type), type_name(tp)); 4311 4312 tn = convert(CVT, 0, tp, tn); 4313 tn->tn_cast = true; 4314 tn->tn_sys = sys; 4315 4316 return tn; 4317 4318 invalid_cast: 4319 /* invalid cast from '%s' to '%s' */ 4320 error(147, type_name(tn->tn_type), type_name(tp)); 4321 return NULL; 4322 } 4323 4324 void 4325 add_function_argument(function_call *call, tnode_t *arg) 4326 { 4327 /* 4328 * If there was a serious error in the expression for the argument, 4329 * create a dummy argument so the positions of the remaining arguments 4330 * will not change. 4331 */ 4332 if (arg == NULL) 4333 arg = build_integer_constant(INT, 0); 4334 4335 if (call->args_len >= call->args_cap) { 4336 call->args_cap += 8; 4337 tnode_t **new_args = expr_zero_alloc( 4338 call->args_cap * sizeof(*call->args), "tnode*[]"); 4339 if (call->args_len > 0) 4340 memcpy(new_args, call->args, 4341 call->args_len * sizeof(*call->args)); 4342 call->args = new_args; 4343 } 4344 call->args[call->args_len++] = arg; 4345 } 4346 4347 /* 4348 * Compare the type of an argument with the corresponding type of a 4349 * prototype parameter. If it is a valid combination, but both types 4350 * are not the same, insert a conversion to convert the argument into 4351 * the type of the parameter. 4352 */ 4353 static tnode_t * 4354 check_prototype_argument( 4355 int n, /* pos of arg */ 4356 type_t *tp, /* expected type (from prototype) */ 4357 tnode_t *tn) /* argument */ 4358 { 4359 tnode_t *ln = xcalloc(1, sizeof(*ln)); 4360 ln->tn_type = expr_unqualified_type(tp); 4361 ln->tn_lvalue = true; 4362 if (typeok(FARG, n, ln, tn)) { 4363 bool dowarn; 4364 if (!types_compatible(tp, tn->tn_type, 4365 true, false, (dowarn = false, &dowarn)) || dowarn) 4366 tn = convert(FARG, n, tp, tn); 4367 } 4368 free(ln); 4369 return tn; 4370 } 4371 4372 /* 4373 * Check types of all function arguments and insert conversions, 4374 * if necessary. 4375 */ 4376 static void 4377 check_function_arguments(const function_call *call) 4378 { 4379 type_t *ftp = call->func->tn_type->t_subt; 4380 4381 /* get # of parameters in the prototype */ 4382 int npar = 0; 4383 for (const sym_t *p = ftp->u.params; p != NULL; p = p->s_next) 4384 npar++; 4385 4386 int narg = (int)call->args_len; 4387 4388 const sym_t *param = ftp->u.params; 4389 if (ftp->t_proto && npar != narg && !(ftp->t_vararg && npar < narg)) { 4390 /* argument mismatch: %d %s passed, %d expected */ 4391 error(150, narg, narg != 1 ? "arguments" : "argument", npar); 4392 param = NULL; 4393 } 4394 4395 for (int i = 0; i < narg; i++) { 4396 tnode_t *arg = call->args[i]; 4397 4398 /* some things which are always not allowed */ 4399 tspec_t at = arg->tn_type->t_tspec; 4400 if (at == VOID) { 4401 /* void expressions may not be arguments, arg #%d */ 4402 error(151, i + 1); 4403 return; 4404 } 4405 if (is_struct_or_union(at) && is_incomplete(arg->tn_type)) { 4406 /* argument cannot have unknown size, arg #%d */ 4407 error(152, i + 1); 4408 return; 4409 } 4410 if (is_integer(at) && 4411 arg->tn_type->t_is_enum && 4412 is_incomplete(arg->tn_type)) { 4413 /* argument cannot have unknown size, arg #%d */ 4414 warning(152, i + 1); 4415 } 4416 4417 arg = cconv(arg); 4418 call->args[i] = arg; 4419 4420 arg = param != NULL 4421 ? check_prototype_argument(i + 1, param->s_type, arg) 4422 : promote(NOOP, true, arg); 4423 call->args[i] = arg; 4424 4425 if (param != NULL) 4426 param = param->s_next; 4427 } 4428 } 4429 4430 tnode_t * 4431 build_function_call(tnode_t *func, bool sys, function_call *call) 4432 { 4433 4434 if (func == NULL) 4435 return NULL; 4436 4437 call->func = func; 4438 check_ctype_function_call(call); 4439 4440 func = cconv(func); 4441 call->func = func; 4442 4443 if (func->tn_type->t_tspec != PTR || 4444 func->tn_type->t_subt->t_tspec != FUNC) { 4445 /* cannot call '%s', must be a function */ 4446 error(149, type_name(func->tn_type)); 4447 return NULL; 4448 } 4449 4450 check_function_arguments(call); 4451 4452 tnode_t *ntn = expr_alloc_tnode(); 4453 ntn->tn_op = CALL; 4454 ntn->tn_type = func->tn_type->t_subt->t_subt; 4455 ntn->tn_sys = sys; 4456 ntn->u.call = call; 4457 return ntn; 4458 } 4459 4460 /* 4461 * Return the value of an integral constant expression. 4462 * If the expression is not constant or its type is not an integer 4463 * type, an error message is printed. 4464 */ 4465 val_t * 4466 integer_constant(tnode_t *tn, bool required) 4467 { 4468 4469 if (tn != NULL) 4470 tn = cconv(tn); 4471 if (tn != NULL) 4472 tn = promote(NOOP, false, tn); 4473 4474 val_t *v = xcalloc(1, sizeof(*v)); 4475 4476 if (tn == NULL) { 4477 lint_assert(seen_error); 4478 debug_step("constant node is null; returning 1 instead"); 4479 v->v_tspec = INT; 4480 v->u.integer = 1; 4481 return v; 4482 } 4483 4484 v->v_tspec = tn->tn_type->t_tspec; 4485 4486 if (tn->tn_op == CON) { 4487 lint_assert(tn->tn_type->t_tspec == tn->u.value.v_tspec); 4488 if (is_integer(tn->u.value.v_tspec)) { 4489 v->v_unsigned_since_c90 = 4490 tn->u.value.v_unsigned_since_c90; 4491 v->u.integer = tn->u.value.u.integer; 4492 return v; 4493 } 4494 v->u.integer = (int64_t)tn->u.value.u.floating; 4495 } else 4496 v->u.integer = 1; 4497 4498 if (required) 4499 /* integral constant expression expected */ 4500 error(55); 4501 else 4502 /* variable array dimension is a C99/GCC extension */ 4503 c99ism(318); 4504 4505 if (!is_integer(v->v_tspec)) 4506 v->v_tspec = INT; 4507 4508 return v; 4509 } 4510 4511 static bool 4512 is_constcond_false(const tnode_t *tn, tspec_t t) 4513 { 4514 return (t == BOOL || t == INT) && 4515 tn->tn_op == CON && tn->u.value.u.integer == 0; 4516 } 4517 4518 /* 4519 * Perform some tests on expressions which can't be done in build_binary() 4520 * and functions called by build_binary(). These tests must be done here 4521 * because we need some information about the context in which the operations 4522 * are performed. 4523 * After all tests are performed and dofreeblk is true, expr() frees the 4524 * memory which is used for the expression. 4525 */ 4526 void 4527 expr(tnode_t *tn, bool vctx, bool cond, bool dofreeblk, bool is_do_while, 4528 const char *stmt_kind) 4529 { 4530 4531 if (tn == NULL) { /* in case of errors */ 4532 expr_free_all(); 4533 return; 4534 } 4535 4536 /* expr() is also called in global initializations */ 4537 if (dcs->d_kind != DLK_EXTERN && !is_do_while) 4538 check_statement_reachable(stmt_kind); 4539 4540 check_expr_misc(tn, vctx, cond, !cond, false, false, false); 4541 if (tn->tn_op == ASSIGN && !tn->tn_parenthesized) { 4542 if (hflag && cond) 4543 /* assignment in conditional context */ 4544 warning(159); 4545 } else if (tn->tn_op == CON) { 4546 if (hflag && cond && !suppress_constcond && 4547 !tn->tn_system_dependent && 4548 !(is_do_while && 4549 is_constcond_false(tn, tn->tn_type->t_tspec))) 4550 /* constant in conditional context */ 4551 warning(161); 4552 } 4553 if (!modtab[tn->tn_op].m_has_side_effect) { 4554 /* 4555 * for left operands of COMMA this warning is already printed 4556 */ 4557 if (tn->tn_op != COMMA && !vctx && !cond) 4558 check_null_effect(tn); 4559 } 4560 debug_node(tn); 4561 4562 if (dofreeblk) 4563 expr_free_all(); 4564 } 4565 4566 /* If the expression has the form '*(arr + idx)', check the array index. */ 4567 static void 4568 check_array_index(const tnode_t *indir, bool taking_address) 4569 { 4570 const tnode_t *plus, *arr, *idx; 4571 4572 if (indir->tn_op == INDIR 4573 && (plus = indir->u.ops.left, plus->tn_op == PLUS) 4574 && plus->u.ops.left->tn_op == ADDR 4575 && (arr = plus->u.ops.left->u.ops.left, true) 4576 && (arr->tn_op == STRING || arr->tn_op == NAME) 4577 && arr->tn_type->t_tspec == ARRAY 4578 && (idx = plus->u.ops.right, idx->tn_op == CON) 4579 && (!is_incomplete(arr->tn_type) || idx->u.value.u.integer < 0)) 4580 goto proceed; 4581 return; 4582 4583 proceed:; 4584 int elsz = length_in_bits(arr->tn_type->t_subt, NULL); 4585 if (elsz == 0) 4586 return; 4587 elsz /= CHAR_SIZE; 4588 4589 /* Change the unit of the index from bytes to element size. */ 4590 int64_t con = is_uinteger(idx->tn_type->t_tspec) 4591 ? (int64_t)((uint64_t)idx->u.value.u.integer / elsz) 4592 : idx->u.value.u.integer / elsz; 4593 4594 int dim = arr->tn_type->u.dimension + (taking_address ? 1 : 0); 4595 4596 if (!is_uinteger(idx->tn_type->t_tspec) && con < 0) 4597 /* array subscript %jd cannot be negative */ 4598 warning(167, (intmax_t)con); 4599 else if (dim > 0 && (uint64_t)con >= (uint64_t)dim) 4600 /* array subscript %ju cannot be > %d */ 4601 warning(168, (uintmax_t)con, dim - 1); 4602 } 4603 4604 static void 4605 check_expr_addr(const tnode_t *ln, bool szof, bool fcall) 4606 { 4607 /* XXX: Taking warn_about_unreachable into account here feels wrong. */ 4608 if (ln->tn_op == NAME && (reached || !warn_about_unreachable)) { 4609 if (!szof) 4610 mark_as_set(ln->u.sym); 4611 mark_as_used(ln->u.sym, fcall, szof); 4612 } 4613 check_array_index(ln, true); 4614 } 4615 4616 /* 4617 * If there is an asm statement in one of the compound statements around, 4618 * there may be other side effects, so don't warn. 4619 */ 4620 static bool 4621 is_asm_around(void) 4622 { 4623 for (decl_level *dl = dcs; dl != NULL; dl = dl->d_enclosing) 4624 if (dl->d_asm) 4625 return true; 4626 return false; 4627 } 4628 4629 static void 4630 check_expr_side_effect(const tnode_t *ln, bool szof) 4631 { 4632 4633 /* XXX: Taking warn_about_unreachable into account here feels wrong. */ 4634 if (ln->tn_op == NAME && (reached || !warn_about_unreachable)) { 4635 scl_t sc = ln->u.sym->s_scl; 4636 if (sc != EXTERN && sc != STATIC && 4637 !ln->u.sym->s_set && !szof && !is_asm_around()) { 4638 /* '%s' may be used before set */ 4639 warning(158, ln->u.sym->s_name); 4640 mark_as_set(ln->u.sym); 4641 } 4642 mark_as_used(ln->u.sym, false, false); 4643 } 4644 } 4645 4646 static void 4647 check_expr_assign(const tnode_t *ln, bool szof) 4648 { 4649 /* XXX: Taking warn_about_unreachable into account here feels wrong. */ 4650 if (ln->tn_op == NAME && !szof && (reached || !warn_about_unreachable)) { 4651 mark_as_set(ln->u.sym); 4652 if (ln->u.sym->s_scl == EXTERN) 4653 outusg(ln->u.sym); 4654 } 4655 check_array_index(ln, false); 4656 } 4657 4658 static void 4659 check_expr_call(const tnode_t *tn, const tnode_t *ln, 4660 bool szof, bool vctx, bool cond, bool retval_discarded) 4661 { 4662 lint_assert(ln->tn_op == ADDR); 4663 lint_assert(ln->u.ops.left->tn_op == NAME); 4664 if (!szof && !is_compiler_builtin(ln->u.ops.left->u.sym->s_name)) 4665 outcall(tn, vctx || cond, retval_discarded); 4666 4667 const function_call *call = tn->u.call; 4668 if (call->args_len == 4 || call->args_len == 5) 4669 check_snprintb(call); 4670 } 4671 4672 static void 4673 check_expr_op(op_t op, const tnode_t *ln, bool szof, bool fcall, bool eqwarn) 4674 { 4675 switch (op) { 4676 case ADDR: 4677 check_expr_addr(ln, szof, fcall); 4678 break; 4679 case LOAD: 4680 check_array_index(ln, false); 4681 /* FALLTHROUGH */ 4682 case INCBEF: 4683 case DECBEF: 4684 case INCAFT: 4685 case DECAFT: 4686 case ADDASS: 4687 case SUBASS: 4688 case MULASS: 4689 case DIVASS: 4690 case MODASS: 4691 case ANDASS: 4692 case ORASS: 4693 case XORASS: 4694 case SHLASS: 4695 case SHRASS: 4696 case REAL: 4697 case IMAG: 4698 check_expr_side_effect(ln, szof); 4699 break; 4700 case ASSIGN: 4701 check_expr_assign(ln, szof); 4702 break; 4703 case EQ: 4704 if (hflag && eqwarn) 4705 /* operator '==' found where '=' was expected */ 4706 warning(160); 4707 break; 4708 default: 4709 break; 4710 } 4711 } 4712 4713 /* 4714 * vctx ??? 4715 * cond whether the expression is a condition that 4716 * will be compared with 0 4717 * eqwarn whether the operator '==' might be a 4718 * misspelled '=' 4719 * fcall whether the expression is a function call 4720 * retval_discarded whether the return value of a function call 4721 * is discarded; such calls will be analyzed by 4722 * lint2 in messages 4, 8 and 9 4723 * szof whether the expression is part of a sizeof 4724 * expression, which means that its value is 4725 * discarded since only the type is relevant 4726 */ 4727 void 4728 check_expr_misc(const tnode_t *tn, bool vctx, bool cond, 4729 bool eqwarn, bool fcall, bool retval_discarded, bool szof) 4730 { 4731 4732 if (tn == NULL) 4733 return; 4734 op_t op = tn->tn_op; 4735 if (op == NAME || op == CON || op == STRING) 4736 return; 4737 bool is_direct = op == CALL 4738 && tn->u.call->func->tn_op == ADDR 4739 && tn->u.call->func->u.ops.left->tn_op == NAME; 4740 if (op == CALL) { 4741 const function_call *call = tn->u.call; 4742 if (is_direct) 4743 check_expr_call(tn, call->func, 4744 szof, vctx, cond, retval_discarded); 4745 bool discard = op == CVT && tn->tn_type->t_tspec == VOID; 4746 check_expr_misc(call->func, false, false, false, is_direct, 4747 discard, szof); 4748 for (size_t i = 0, n = call->args_len; i < n; i++) 4749 check_expr_misc(call->args[i], 4750 true, false, false, false, false, szof); 4751 return; 4752 } 4753 4754 lint_assert(has_operands(tn)); 4755 tnode_t *ln = tn->u.ops.left; 4756 tnode_t *rn = tn->u.ops.right; 4757 check_expr_op(op, ln, szof, fcall, eqwarn); 4758 4759 const mod_t *mp = &modtab[op]; 4760 bool cvctx = mp->m_value_context; 4761 bool ccond = mp->m_compares_with_zero; 4762 bool eq = mp->m_warn_if_operand_eq && 4763 !ln->tn_parenthesized && 4764 rn != NULL && !rn->tn_parenthesized; 4765 4766 /* 4767 * Values of operands of ':' are not used if the type of at least 4768 * one of the operands (for GCC compatibility) is 'void'. 4769 * 4770 * XXX test/value context of QUEST should probably be used as 4771 * context for both operands of COLON. 4772 */ 4773 if (op == COLON && tn->tn_type->t_tspec == VOID) 4774 cvctx = ccond = false; 4775 bool discard = op == CVT && tn->tn_type->t_tspec == VOID; 4776 check_expr_misc(ln, cvctx, ccond, eq, is_direct, discard, szof); 4777 4778 switch (op) { 4779 case LOGAND: 4780 case LOGOR: 4781 check_expr_misc(rn, false, true, eq, false, false, szof); 4782 break; 4783 case COLON: 4784 check_expr_misc(rn, cvctx, ccond, eq, false, false, szof); 4785 break; 4786 case COMMA: 4787 check_expr_misc(rn, vctx, cond, false, false, false, szof); 4788 break; 4789 default: 4790 if (mp->m_binary) 4791 check_expr_misc(rn, true, false, eq, false, false, 4792 szof); 4793 break; 4794 } 4795 } 4796 4797 /* 4798 * Return whether the expression can be used for static initialization. 4799 * 4800 * Constant initialization expressions must be constant or an address 4801 * of a static object with an optional offset. In the first case, 4802 * the result is returned in *offsp. In the second case, the static 4803 * object is returned in *symp and the offset in *offsp. 4804 * 4805 * The expression can consist of PLUS, MINUS, ADDR, NAME, STRING and 4806 * CON. Type conversions are allowed if they do not change binary 4807 * representation (including width). 4808 * 4809 * C99 6.6 "Constant expressions" 4810 * C99 6.7.8p4 restricts initializers for static storage duration 4811 */ 4812 bool 4813 constant_addr(const tnode_t *tn, const sym_t **symp, ptrdiff_t *offsp) 4814 { 4815 const sym_t *sym; 4816 ptrdiff_t offs1, offs2; 4817 tspec_t t, ot; 4818 4819 switch (tn->tn_op) { 4820 case MINUS: 4821 if (tn->u.ops.right->tn_op == CVT) 4822 return constant_addr(tn->u.ops.right, symp, offsp); 4823 else if (tn->u.ops.right->tn_op != CON) 4824 return false; 4825 /* FALLTHROUGH */ 4826 case PLUS: 4827 offs1 = offs2 = 0; 4828 if (tn->u.ops.left->tn_op == CON) { 4829 offs1 = (ptrdiff_t)tn->u.ops.left->u.value.u.integer; 4830 if (!constant_addr(tn->u.ops.right, &sym, &offs2)) 4831 return false; 4832 } else if (tn->u.ops.right->tn_op == CON) { 4833 offs2 = (ptrdiff_t)tn->u.ops.right->u.value.u.integer; 4834 if (tn->tn_op == MINUS) 4835 offs2 = -offs2; 4836 if (!constant_addr(tn->u.ops.left, &sym, &offs1)) 4837 return false; 4838 } else { 4839 return false; 4840 } 4841 *symp = sym; 4842 *offsp = offs1 + offs2; 4843 return true; 4844 case ADDR: 4845 if (tn->u.ops.left->tn_op == NAME) { 4846 *symp = tn->u.ops.left->u.sym; 4847 *offsp = 0; 4848 return true; 4849 } else { 4850 /* 4851 * If this were the front end of a compiler, we would 4852 * return a label instead of 0, at least if 4853 * 'tn->u.ops.left->tn_op == STRING'. 4854 */ 4855 *symp = NULL; 4856 *offsp = 0; 4857 return true; 4858 } 4859 case CVT: 4860 t = tn->tn_type->t_tspec; 4861 ot = tn->u.ops.left->tn_type->t_tspec; 4862 if ((!is_integer(t) && t != PTR) || 4863 (!is_integer(ot) && ot != PTR)) { 4864 return false; 4865 } 4866 #if 0 4867 /*- 4868 * consider: 4869 * struct foo { 4870 * unsigned char a; 4871 * } f = { 4872 * (unsigned char)(unsigned long) 4873 * (&(((struct foo *)0)->a)) 4874 * }; 4875 * since psize(unsigned long) != psize(unsigned char), 4876 * this fails. 4877 */ 4878 else if (psize(t) != psize(ot)) 4879 return -1; 4880 #endif 4881 return constant_addr(tn->u.ops.left, symp, offsp); 4882 default: 4883 return false; 4884 } 4885 } 4886 4887 /* Append s2 to s1, then free s2. */ 4888 buffer * 4889 cat_strings(buffer *s1, buffer *s2) 4890 { 4891 4892 if ((s1->data != NULL) != (s2->data != NULL)) { 4893 /* cannot concatenate wide and regular string literals */ 4894 error(292); 4895 return s1; 4896 } 4897 4898 if (s1->data != NULL) { 4899 while (s1->len + s2->len + 1 > s1->cap) 4900 s1->cap *= 2; 4901 s1->data = xrealloc(s1->data, s1->cap); 4902 memcpy(s1->data + s1->len, s2->data, s2->len + 1); 4903 free(s2->data); 4904 } 4905 s1->len += s2->len; 4906 free(s2); 4907 4908 return s1; 4909 } 4910 4911 4912 typedef struct stmt_expr { 4913 memory_pool se_mem; 4914 sym_t *se_sym; 4915 struct stmt_expr *se_enclosing; 4916 } stmt_expr; 4917 4918 static stmt_expr *stmt_exprs; 4919 4920 void 4921 begin_statement_expr(void) 4922 { 4923 debug_enter(); 4924 4925 stmt_expr *se = xmalloc(sizeof(*se)); 4926 se->se_mem = expr_save_memory(); 4927 se->se_sym = NULL; 4928 se->se_enclosing = stmt_exprs; 4929 stmt_exprs = se; 4930 } 4931 4932 void 4933 do_statement_expr(tnode_t *tn) 4934 { 4935 block_level--; 4936 mem_block_level--; 4937 stmt_exprs->se_sym = tn != NULL 4938 ? mktempsym(block_dup_type(tn->tn_type)) 4939 : NULL; /* after a syntax error */ 4940 mem_block_level++; 4941 block_level++; 4942 /* '({ ... })' is a GCC extension */ 4943 gnuism(320); 4944 } 4945 4946 tnode_t * 4947 end_statement_expr(void) 4948 { 4949 tnode_t *tn; 4950 4951 stmt_expr *se = stmt_exprs; 4952 if (se->se_sym == NULL) { 4953 tn = NULL; /* after a syntax error */ 4954 goto end; 4955 } 4956 4957 tn = build_name(se->se_sym, false); 4958 (void)expr_save_memory(); /* leak */ 4959 expr_restore_memory(se->se_mem); 4960 stmt_exprs = se->se_enclosing; 4961 free(se); 4962 4963 end: 4964 debug_leave(); 4965 return tn; 4966 } 4967 4968 bool 4969 in_statement_expr(void) 4970 { 4971 return stmt_exprs != NULL; 4972 } 4973
Indexes created Mon Sep 22 10:09:38 GMT 2025