tree.c revision 1.648
1 /* $NetBSD: tree.c,v 1.648 2024/06/17 17:06:47 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 1.648 2024/06/17 17:06:47 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 bset; /* bits that are definitely set */ 59 uint64_t bclr; /* bits that are definitely clear */ 60 } integer_constraints; 61 62 63 static uint64_t 64 u64_fill_right(uint64_t x) 65 { 66 x |= x >> 1; 67 x |= x >> 2; 68 x |= x >> 4; 69 x |= x >> 8; 70 x |= x >> 16; 71 x |= x >> 32; 72 return x; 73 } 74 75 static bool 76 str_ends_with(const char *haystack, const char *needle) 77 { 78 size_t hlen = strlen(haystack); 79 size_t nlen = strlen(needle); 80 81 return nlen <= hlen && 82 memcmp(haystack + hlen - nlen, needle, nlen) == 0; 83 } 84 85 static unsigned 86 width_in_bits(const type_t *tp) 87 { 88 89 lint_assert(is_integer(tp->t_tspec)); 90 return tp->t_bitfield 91 ? tp->t_bit_field_width 92 : size_in_bits(tp->t_tspec); 93 } 94 95 static int 96 portable_rank_cmp(tspec_t t1, tspec_t t2) 97 { 98 const ttab_t *p1 = type_properties(t1), *p2 = type_properties(t2); 99 lint_assert(p1->tt_rank_kind == p2->tt_rank_kind); 100 lint_assert(p1->tt_rank_value > 0); 101 lint_assert(p2->tt_rank_value > 0); 102 return (int)p1->tt_rank_value - (int)p2->tt_rank_value; 103 } 104 105 static bool 106 ic_maybe_signed(const type_t *tp, const integer_constraints *ic) 107 { 108 return !is_uinteger(tp->t_tspec) && ic->bclr >> 63 == 0; 109 } 110 111 static integer_constraints 112 ic_any(const type_t *tp) 113 { 114 integer_constraints c; 115 116 uint64_t vbits = value_bits(width_in_bits(tp)); 117 if (is_uinteger(tp->t_tspec)) { 118 c.smin = INT64_MIN; 119 c.smax = INT64_MAX; 120 c.umin = 0; 121 c.umax = vbits; 122 c.bset = 0; 123 c.bclr = ~c.umax; 124 } else { 125 c.smin = (int64_t)-1 - (int64_t)(vbits >> 1); 126 c.smax = (int64_t)(vbits >> 1); 127 c.umin = 0; 128 c.umax = UINT64_MAX; 129 c.bset = 0; 130 c.bclr = 0; 131 } 132 return c; 133 } 134 135 static integer_constraints 136 ic_con(const type_t *tp, const val_t *v) 137 { 138 integer_constraints c; 139 140 lint_assert(is_integer(tp->t_tspec)); 141 int64_t si = v->u.integer; 142 uint64_t ui = (uint64_t)si; 143 c.smin = si; 144 c.smax = si; 145 c.umin = ui; 146 c.umax = ui; 147 c.bset = ui; 148 c.bclr = ~ui; 149 return c; 150 } 151 152 static integer_constraints 153 ic_cvt(const type_t *ntp, const type_t *otp, integer_constraints a) 154 { 155 unsigned nw = width_in_bits(ntp); 156 unsigned ow = width_in_bits(otp); 157 bool nu = is_uinteger(ntp->t_tspec); 158 bool ou = is_uinteger(otp->t_tspec); 159 160 if (nw >= ow && nu == ou) 161 return a; 162 if (nw > ow && ou) 163 return a; 164 return ic_any(ntp); 165 } 166 167 static integer_constraints 168 ic_bitand(integer_constraints a, integer_constraints b) 169 { 170 integer_constraints c; 171 172 c.smin = INT64_MIN; 173 c.smax = INT64_MAX; 174 c.umin = 0; 175 c.umax = UINT64_MAX; 176 c.bset = a.bset & b.bset; 177 c.bclr = a.bclr | b.bclr; 178 return c; 179 } 180 181 static integer_constraints 182 ic_bitor(integer_constraints a, integer_constraints b) 183 { 184 integer_constraints c; 185 186 c.smin = INT64_MIN; 187 c.smax = INT64_MAX; 188 c.umin = 0; 189 c.umax = UINT64_MAX; 190 c.bset = a.bset | b.bset; 191 c.bclr = a.bclr & b.bclr; 192 return c; 193 } 194 195 static integer_constraints 196 ic_mod(const type_t *tp, integer_constraints a, integer_constraints b) 197 { 198 integer_constraints c; 199 200 if (ic_maybe_signed(tp, &a) || ic_maybe_signed(tp, &b)) 201 return ic_any(tp); 202 203 c.smin = INT64_MIN; 204 c.smax = INT64_MAX; 205 c.umin = 0; 206 c.umax = b.umax - 1; 207 c.bset = 0; 208 c.bclr = ~u64_fill_right(c.umax); 209 return c; 210 } 211 212 static integer_constraints 213 ic_shl(const type_t *tp, integer_constraints a, integer_constraints b) 214 { 215 integer_constraints c; 216 unsigned int amount; 217 218 if (ic_maybe_signed(tp, &a)) 219 return ic_any(tp); 220 221 if (b.smin == b.smax && b.smin >= 0 && b.smin < 64) 222 amount = (unsigned int)b.smin; 223 else if (b.umin == b.umax && b.umin < 64) 224 amount = (unsigned int)b.umin; 225 else 226 return ic_any(tp); 227 228 c.smin = INT64_MIN; 229 c.smax = INT64_MAX; 230 c.umin = 0; 231 c.umax = UINT64_MAX; 232 c.bset = a.bset << amount; 233 c.bclr = a.bclr << amount | (((uint64_t)1 << amount) - 1); 234 return c; 235 } 236 237 static integer_constraints 238 ic_shr(const type_t *tp, integer_constraints a, integer_constraints b) 239 { 240 integer_constraints c; 241 unsigned int amount; 242 243 if (ic_maybe_signed(tp, &a)) 244 return ic_any(tp); 245 246 if (b.smin == b.smax && b.smin >= 0 && b.smin < 64) 247 amount = (unsigned int)b.smin; 248 else if (b.umin == b.umax && b.umin < 64) 249 amount = (unsigned int)b.umin; 250 else 251 return ic_any(tp); 252 253 c.smin = INT64_MIN; 254 c.smax = INT64_MAX; 255 c.umin = 0; 256 c.umax = UINT64_MAX; 257 c.bset = a.bset >> amount; 258 c.bclr = a.bclr >> amount | ~(~(uint64_t)0 >> amount); 259 return c; 260 } 261 262 static integer_constraints 263 ic_cond(integer_constraints a, integer_constraints b) 264 { 265 integer_constraints c; 266 267 c.smin = a.smin < b.smin ? a.smin : b.smin; 268 c.smax = a.smax > b.smax ? a.smax : b.smax; 269 c.umin = a.umin < b.umin ? a.umin : b.umin; 270 c.umax = a.umax > b.umax ? a.umax : b.umax; 271 c.bset = a.bset | b.bset; 272 c.bclr = a.bclr & b.bclr; 273 return c; 274 } 275 276 static integer_constraints 277 ic_expr(const tnode_t *tn) 278 { 279 integer_constraints lc, rc; 280 281 lint_assert(is_integer(tn->tn_type->t_tspec)); 282 283 switch (tn->tn_op) { 284 case CON: 285 return ic_con(tn->tn_type, &tn->u.value); 286 case CVT: 287 if (!is_integer(tn->u.ops.left->tn_type->t_tspec)) 288 return ic_any(tn->tn_type); 289 lc = ic_expr(tn->u.ops.left); 290 return ic_cvt(tn->tn_type, tn->u.ops.left->tn_type, lc); 291 case MOD: 292 lc = ic_expr(before_conversion(tn->u.ops.left)); 293 rc = ic_expr(before_conversion(tn->u.ops.right)); 294 return ic_mod(tn->tn_type, lc, rc); 295 case SHL: 296 lc = ic_expr(tn->u.ops.left); 297 rc = ic_expr(tn->u.ops.right); 298 return ic_shl(tn->tn_type, lc, rc); 299 case SHR: 300 lc = ic_expr(tn->u.ops.left); 301 rc = ic_expr(tn->u.ops.right); 302 return ic_shr(tn->tn_type, lc, rc); 303 case BITAND: 304 lc = ic_expr(tn->u.ops.left); 305 rc = ic_expr(tn->u.ops.right); 306 return ic_bitand(lc, rc); 307 case BITOR: 308 lc = ic_expr(tn->u.ops.left); 309 rc = ic_expr(tn->u.ops.right); 310 return ic_bitor(lc, rc); 311 case QUEST: 312 lc = ic_expr(tn->u.ops.right->u.ops.left); 313 rc = ic_expr(tn->u.ops.right->u.ops.right); 314 return ic_cond(lc, rc); 315 default: 316 return ic_any(tn->tn_type); 317 } 318 } 319 320 uint64_t 321 possible_bits(const tnode_t *tn) 322 { 323 return ~ic_expr(tn).bclr; 324 } 325 326 bool 327 attributes_contain(const attribute_list *attrs, const char *str) 328 { 329 for (size_t i = 0, n = attrs->len; i < n; i++) { 330 const attribute *attr = attrs->attrs + i; 331 if (attr->prefix == NULL && strcmp(attr->name, str) == 0) 332 return true; 333 } 334 return false; 335 } 336 337 /* Build 'pointer to tp', 'array of tp' or 'function returning tp'. */ 338 type_t * 339 block_derive_type(type_t *tp, tspec_t t) 340 { 341 342 type_t *tp2 = block_zero_alloc(sizeof(*tp2), "type"); 343 tp2->t_tspec = t; 344 tp2->t_subt = tp; 345 return tp2; 346 } 347 348 /* 349 * Derive 'pointer to tp' or 'function returning tp'. 350 * The memory is freed at the end of the current expression. 351 */ 352 type_t * 353 expr_derive_type(type_t *tp, tspec_t t) 354 { 355 356 type_t *tp2 = expr_zero_alloc(sizeof(*tp2), "type"); 357 tp2->t_tspec = t; 358 tp2->t_subt = tp; 359 return tp2; 360 } 361 362 /* Create an expression from a unary or binary operator and its operands. */ 363 static tnode_t * 364 build_op(op_t op, bool sys, type_t *type, tnode_t *ln, tnode_t *rn) 365 { 366 367 tnode_t *ntn = expr_alloc_tnode(); 368 ntn->tn_op = op; 369 ntn->tn_type = type; 370 ntn->tn_sys = sys; 371 ntn->u.ops.left = ln; 372 ntn->u.ops.right = rn; 373 374 if (op == INDIR || op == FSEL) { 375 lint_assert(ln->tn_type->t_tspec == PTR); 376 tspec_t t = ln->tn_type->t_subt->t_tspec; 377 ntn->tn_lvalue = t != FUNC && t != VOID; 378 } 379 380 return ntn; 381 } 382 383 tnode_t * 384 build_constant(type_t *tp, val_t *v) 385 { 386 387 tnode_t *n = expr_alloc_tnode(); 388 n->tn_op = CON; 389 n->tn_type = tp; 390 n->u.value = *v; 391 n->u.value.v_tspec = tp->t_tspec; 392 free(v); 393 return n; 394 } 395 396 static tnode_t * 397 build_integer_constant(tspec_t t, int64_t si) 398 { 399 400 tnode_t *n = expr_alloc_tnode(); 401 n->tn_op = CON; 402 n->tn_type = gettyp(t); 403 n->u.value.v_tspec = t; 404 n->u.value.v_unsigned_since_c90 = false; 405 n->u.value.v_char_constant = false; 406 n->u.value.u.integer = si; 407 return n; 408 } 409 410 static void 411 fallback_symbol(sym_t *sym) 412 { 413 414 if (Tflag && fallback_symbol_strict_bool(sym)) 415 return; 416 417 if (funcsym != NULL && (strcmp(sym->s_name, "__FUNCTION__") == 0 || 418 strcmp(sym->s_name, "__PRETTY_FUNCTION__") == 0)) { 419 /* __FUNCTION__/__PRETTY_FUNCTION__ is a GCC extension */ 420 gnuism(316); 421 goto return_function_name; 422 } 423 424 if (funcsym != NULL && strcmp(sym->s_name, "__func__") == 0) { 425 if (!allow_c99) 426 /* __func__ is a C99 feature */ 427 warning(317); 428 /* C11 6.4.2.2 */ 429 return_function_name: 430 sym->s_type = block_derive_type(gettyp(CHAR), ARRAY); 431 sym->s_type->t_const = true; 432 sym->s_type->u.dimension = (int)strlen(funcsym->s_name) + 1; 433 return; 434 } 435 436 /* '%s' undefined */ 437 error(99, sym->s_name); 438 } 439 440 /* 441 * Functions that are predeclared by GCC or other compilers can be called 442 * with arbitrary arguments. Since lint usually runs after a successful 443 * compilation, it's the compiler's job to catch any errors. 444 */ 445 bool 446 is_compiler_builtin(const char *name) 447 { 448 /* https://gcc.gnu.org/onlinedocs/gcc/C-Extensions.html */ 449 if (allow_gcc) { 450 if (strncmp(name, "__atomic_", 9) == 0 || 451 strncmp(name, "__builtin_", 10) == 0 || 452 strcmp(name, "alloca") == 0 || 453 /* obsolete but still in use, as of 2021 */ 454 strncmp(name, "__sync_", 7) == 0) 455 return true; 456 } 457 458 /* https://software.intel.com/sites/landingpage/IntrinsicsGuide/ */ 459 if (strncmp(name, "_mm_", 4) == 0) 460 return true; 461 462 return false; 463 } 464 465 /* https://gcc.gnu.org/onlinedocs/gcc/Integer-Overflow-Builtins.html */ 466 static bool 467 is_gcc_bool_builtin(const char *name) 468 { 469 return strncmp(name, "__builtin_", 10) == 0 && 470 (str_ends_with(name, "_overflow") || 471 str_ends_with(name, "_overflow_p")); 472 } 473 474 static void 475 build_name_call(sym_t *sym) 476 { 477 478 if (is_compiler_builtin(sym->s_name)) { 479 /* 480 * Do not warn about these, just assume that they are regular 481 * functions compatible with non-prototype calling conventions. 482 */ 483 if (allow_gcc && is_gcc_bool_builtin(sym->s_name)) 484 sym->s_type = gettyp(BOOL); 485 } else if (allow_c99) 486 /* function '%s' implicitly declared to return int */ 487 error(215, sym->s_name); 488 else if (!allow_trad) 489 /* function '%s' implicitly declared to return int */ 490 warning(215, sym->s_name); 491 492 /* XXX if !allow_c90, the symbol should be exported to level 0 */ 493 sym->s_type = block_derive_type(sym->s_type, FUNC); 494 } 495 496 /* Create a node for a name (symbol table entry). */ 497 tnode_t * 498 build_name(sym_t *sym, bool is_funcname) 499 { 500 501 if (sym->s_scl == NO_SCL && !in_gcc_attribute) { 502 sym->s_scl = EXTERN; 503 sym->s_def = DECL; 504 if (is_funcname) 505 build_name_call(sym); 506 else 507 fallback_symbol(sym); 508 } 509 510 lint_assert(sym->s_kind == SK_VCFT || sym->s_kind == SK_MEMBER); 511 512 tnode_t *n = expr_alloc_tnode(); 513 n->tn_type = sym->s_type; 514 if (sym->s_scl == BOOL_CONST) { 515 n->tn_op = CON; 516 n->u.value.v_tspec = BOOL; 517 n->u.value.v_unsigned_since_c90 = false; 518 n->u.value.v_char_constant = false; 519 n->u.value.u.integer = sym->u.s_bool_constant ? 1 : 0; 520 } else if (sym->s_scl == ENUM_CONST) { 521 n->tn_op = CON; 522 n->u.value.v_tspec = INT; /* ENUM is in n->tn_type */ 523 n->u.value.v_unsigned_since_c90 = false; 524 n->u.value.v_char_constant = false; 525 n->u.value.u.integer = sym->u.s_enum_constant; 526 } else { 527 n->tn_op = NAME; 528 n->u.sym = sym; 529 if (sym->s_kind == SK_VCFT && sym->s_type->t_tspec != FUNC) 530 n->tn_lvalue = true; 531 } 532 533 return n; 534 } 535 536 tnode_t * 537 build_string(buffer *lit) 538 { 539 size_t value_len = lit->len; 540 if (lit->data != NULL) { 541 quoted_iterator it = { .end = 0 }; 542 for (value_len = 0; quoted_next(lit, &it); value_len++) 543 continue; 544 } 545 546 type_t *tp = expr_zero_alloc(sizeof(*tp), "type"); 547 tp->t_tspec = ARRAY; 548 tp->t_subt = gettyp(lit->data != NULL ? CHAR : WCHAR_TSPEC); 549 tp->u.dimension = (int)(value_len + 1); 550 551 tnode_t *n = expr_alloc_tnode(); 552 n->tn_op = STRING; 553 n->tn_type = tp; 554 n->tn_lvalue = true; 555 556 n->u.str_literals = expr_zero_alloc(sizeof(*n->u.str_literals), "tnode.string"); 557 n->u.str_literals->len = lit->len; 558 559 if (lit->data != NULL) { 560 n->u.str_literals->data = expr_zero_alloc(lit->len + 1, 561 "tnode.string.data"); 562 (void)memcpy(n->u.str_literals->data, lit->data, lit->len + 1); 563 free(lit->data); 564 } 565 free(lit); 566 567 return n; 568 } 569 570 tnode_t * 571 build_generic_selection(const tnode_t *expr, 572 struct generic_association *sel) 573 { 574 tnode_t *default_result = NULL; 575 576 for (; sel != NULL; sel = sel->ga_prev) { 577 if (expr != NULL && 578 types_compatible(sel->ga_arg, expr->tn_type, 579 false, false, NULL)) 580 return sel->ga_result; 581 else if (sel->ga_arg == NULL) 582 default_result = sel->ga_result; 583 } 584 return default_result; 585 } 586 587 static bool 588 is_out_of_char_range(const tnode_t *tn) 589 { 590 return tn->tn_op == CON && 591 !tn->u.value.v_char_constant && 592 !(0 <= tn->u.value.u.integer && 593 tn->u.value.u.integer < 1 << (CHAR_SIZE - 1)); 594 } 595 596 static bool 597 check_nonportable_char_comparison(op_t op, 598 const tnode_t *ln, tspec_t lt, 599 const tnode_t *rn, tspec_t rt) 600 { 601 if (!(hflag || pflag)) 602 return true; 603 604 if (lt == CHAR && is_out_of_char_range(rn)) { 605 char buf[128]; 606 (void)snprintf(buf, sizeof(buf), "%s %d", 607 op_name(op), (int)rn->u.value.u.integer); 608 /* nonportable character comparison '%s' */ 609 warning(230, buf); 610 return false; 611 } 612 if (rt == CHAR && is_out_of_char_range(ln)) { 613 char buf[128]; 614 (void)snprintf(buf, sizeof(buf), "%d %s ?", 615 (int)ln->u.value.u.integer, op_name(op)); 616 /* nonportable character comparison '%s' */ 617 warning(230, buf); 618 return false; 619 } 620 return true; 621 } 622 623 static void 624 check_integer_comparison(op_t op, tnode_t *ln, tnode_t *rn) 625 { 626 627 tspec_t lt = ln->tn_type->t_tspec; 628 tspec_t rt = rn->tn_type->t_tspec; 629 630 if (ln->tn_op != CON && rn->tn_op != CON) 631 return; 632 633 if (!is_integer(lt) || !is_integer(rt)) 634 return; 635 636 if (any_query_enabled && !in_system_header) { 637 if (lt == CHAR && rn->tn_op == CON && 638 !rn->u.value.v_char_constant) { 639 /* comparison '%s' of 'char' with plain integer %d */ 640 query_message(14, 641 op_name(op), (int)rn->u.value.u.integer); 642 } 643 if (rt == CHAR && ln->tn_op == CON && 644 !ln->u.value.v_char_constant) { 645 /* comparison '%s' of 'char' with plain integer %d */ 646 query_message(14, 647 op_name(op), (int)ln->u.value.u.integer); 648 } 649 } 650 651 if (!check_nonportable_char_comparison(op, ln, lt, rn, rt)) 652 return; 653 654 if (is_uinteger(lt) && !is_uinteger(rt) && 655 rn->tn_op == CON && rn->u.value.u.integer <= 0) { 656 if (rn->u.value.u.integer < 0) { 657 /* operator '%s' compares '%s' with '%s' */ 658 warning(162, op_name(op), 659 type_name(ln->tn_type), "negative constant"); 660 } else if (op == LT || op == GE) 661 /* operator '%s' compares '%s' with '%s' */ 662 warning(162, op_name(op), type_name(ln->tn_type), "0"); 663 return; 664 } 665 if (is_uinteger(rt) && !is_uinteger(lt) && 666 ln->tn_op == CON && ln->u.value.u.integer <= 0) { 667 if (ln->u.value.u.integer < 0) { 668 /* operator '%s' compares '%s' with '%s' */ 669 warning(162, op_name(op), 670 "negative constant", type_name(rn->tn_type)); 671 } else if (op == GT || op == LE) 672 /* operator '%s' compares '%s' with '%s' */ 673 warning(162, op_name(op), "0", type_name(rn->tn_type)); 674 return; 675 } 676 } 677 678 static const tspec_t arith_rank[] = { 679 LDOUBLE, DOUBLE, FLOAT, 680 #ifdef INT128_SIZE 681 UINT128, INT128, 682 #endif 683 ULLONG, LLONG, 684 ULONG, LONG, 685 UINT, INT, 686 }; 687 688 /* Keep unsigned in traditional C */ 689 static tspec_t 690 usual_arithmetic_conversion_trad(tspec_t lt, tspec_t rt) 691 { 692 693 size_t i; 694 for (i = 0; arith_rank[i] != INT; i++) 695 if (lt == arith_rank[i] || rt == arith_rank[i]) 696 break; 697 698 tspec_t t = arith_rank[i]; 699 if (is_uinteger(lt) || is_uinteger(rt)) 700 if (is_integer(t) && !is_uinteger(t)) 701 return unsigned_type(t); 702 return t; 703 } 704 705 static tspec_t 706 usual_arithmetic_conversion_c90(tspec_t lt, tspec_t rt) 707 { 708 709 if (lt == rt) 710 return lt; 711 712 if (lt == LCOMPLEX || rt == LCOMPLEX) 713 return LCOMPLEX; 714 if (lt == DCOMPLEX || rt == DCOMPLEX) 715 return DCOMPLEX; 716 if (lt == FCOMPLEX || rt == FCOMPLEX) 717 return FCOMPLEX; 718 if (lt == LDOUBLE || rt == LDOUBLE) 719 return LDOUBLE; 720 if (lt == DOUBLE || rt == DOUBLE) 721 return DOUBLE; 722 if (lt == FLOAT || rt == FLOAT) 723 return FLOAT; 724 725 if (size_in_bits(lt) > size_in_bits(rt)) 726 return lt; 727 if (size_in_bits(lt) < size_in_bits(rt)) 728 return rt; 729 730 size_t i; 731 for (i = 3; arith_rank[i] != INT; i++) 732 if (arith_rank[i] == lt || arith_rank[i] == rt) 733 break; 734 if ((is_uinteger(lt) || is_uinteger(rt)) && 735 !is_uinteger(arith_rank[i])) 736 i--; 737 return arith_rank[i]; 738 } 739 740 static tnode_t * 741 apply_usual_arithmetic_conversions(op_t op, tnode_t *tn, tspec_t t) 742 { 743 type_t *ntp = expr_dup_type(tn->tn_type); 744 ntp->t_tspec = t; 745 if (tn->tn_op != CON) { 746 /* usual arithmetic conversion for '%s' from '%s' to '%s' */ 747 query_message(4, op_name(op), 748 type_name(tn->tn_type), type_name(ntp)); 749 } 750 return convert(op, 0, ntp, tn); 751 } 752 753 /* 754 * Apply the "usual arithmetic conversions" (C99 6.3.1.8), which gives both 755 * operands the same type. 756 */ 757 static void 758 balance(op_t op, tnode_t **lnp, tnode_t **rnp) 759 { 760 761 tspec_t lt = (*lnp)->tn_type->t_tspec; 762 tspec_t rt = (*rnp)->tn_type->t_tspec; 763 if (!is_arithmetic(lt) || !is_arithmetic(rt)) 764 return; 765 766 tspec_t t = allow_c90 767 ? usual_arithmetic_conversion_c90(lt, rt) 768 : usual_arithmetic_conversion_trad(lt, rt); 769 770 if (modtab[op].m_comparison 771 && is_integer(lt) && (*lnp)->tn_op != CON 772 && is_floating(t) && (*rnp)->tn_op == CON) 773 /* comparing integer '%s' to floating point constant %Lg */ 774 warning(379, type_name((*lnp)->tn_type), 775 (*rnp)->u.value.u.floating); 776 777 if (t != lt) 778 *lnp = apply_usual_arithmetic_conversions(op, *lnp, t); 779 if (t != rt) 780 *rnp = apply_usual_arithmetic_conversions(op, *rnp, t); 781 782 if (is_integer(t)) { 783 unsigned lw = width_in_bits((*lnp)->tn_type); 784 unsigned rw = width_in_bits((*rnp)->tn_type); 785 if (lw < rw) 786 *lnp = convert(NOOP, 0, (*rnp)->tn_type, *lnp); 787 if (rw < lw) 788 *rnp = convert(NOOP, 0, (*lnp)->tn_type, *rnp); 789 } 790 } 791 792 static tnode_t * 793 build_address(bool sys, tnode_t *tn, bool force) 794 { 795 tspec_t t; 796 797 if (!force && ((t = tn->tn_type->t_tspec) == ARRAY || t == FUNC)) { 798 if (!allow_c90) 799 /* '&' before array or function: ignored */ 800 warning(127); 801 return tn; 802 } 803 804 /* eliminate '&*' */ 805 if (tn->tn_op == INDIR && 806 tn->u.ops.left->tn_type->t_tspec == PTR && 807 tn->u.ops.left->tn_type->t_subt == tn->tn_type) { 808 return tn->u.ops.left; 809 } 810 811 return build_op(ADDR, sys, expr_derive_type(tn->tn_type, PTR), 812 tn, NULL); 813 } 814 815 static uint64_t 816 fold_unsigned_integer(op_t op, uint64_t l, uint64_t r, 817 uint64_t max_value, bool *overflow) 818 { 819 switch (op) { 820 case COMPL: 821 return ~l & max_value; 822 case UPLUS: 823 return +l; 824 case UMINUS: 825 return -l & max_value; 826 case MULT: 827 *overflow = r > 0 && l > max_value / r; 828 return l * r; 829 case DIV: 830 if (r == 0) { 831 /* division by 0 */ 832 error(139); 833 return max_value; 834 } 835 return l / r; 836 case MOD: 837 if (r == 0) { 838 /* modulus by 0 */ 839 error(140); 840 return 0; 841 } 842 return l % r; 843 case PLUS: 844 *overflow = l > max_value - r; 845 return l + r; 846 case MINUS: 847 *overflow = l < r; 848 return l - r; 849 case SHL: 850 /* TODO: warn about out-of-bounds 'r'. */ 851 /* TODO: warn about overflow. */ 852 return l << (r & 63); 853 case SHR: 854 /* TODO: warn about out-of-bounds 'r'. */ 855 return l >> (r & 63); 856 case LT: 857 return l < r ? 1 : 0; 858 case LE: 859 return l <= r ? 1 : 0; 860 case GT: 861 return l > r ? 1 : 0; 862 case GE: 863 return l >= r ? 1 : 0; 864 case EQ: 865 return l == r ? 1 : 0; 866 case NE: 867 return l != r ? 1 : 0; 868 case BITAND: 869 return l & r; 870 case BITXOR: 871 return l ^ r; 872 case BITOR: 873 return l | r; 874 default: 875 lint_assert(/*CONSTCOND*/false); 876 /* NOTREACHED */ 877 } 878 } 879 880 static int64_t 881 fold_signed_integer(op_t op, int64_t l, int64_t r, 882 int64_t min_value, int64_t max_value, bool *overflow) 883 { 884 switch (op) { 885 case COMPL: 886 return ~l; 887 case UPLUS: 888 return +l; 889 case UMINUS: 890 *overflow = l == min_value; 891 return *overflow ? l : -l; 892 case MULT:; 893 uint64_t al = l >= 0 ? (uint64_t)l : -(uint64_t)l; 894 uint64_t ar = r >= 0 ? (uint64_t)r : -(uint64_t)r; 895 bool neg = (l >= 0) != (r >= 0); 896 uint64_t max_prod = (uint64_t)max_value + (neg ? 1 : 0); 897 if (al > 0 && ar > max_prod / al) { 898 *overflow = true; 899 return neg ? min_value : max_value; 900 } 901 return l * r; 902 case DIV: 903 if (r == 0) { 904 /* division by 0 */ 905 error(139); 906 return max_value; 907 } 908 if (l == min_value && r == -1) { 909 *overflow = true; 910 return l; 911 } 912 return l / r; 913 case MOD: 914 if (r == 0) { 915 /* modulus by 0 */ 916 error(140); 917 return 0; 918 } 919 if (l == min_value && r == -1) { 920 *overflow = true; 921 return 0; 922 } 923 return l % r; 924 case PLUS: 925 if (r > 0 && l > max_value - r) { 926 *overflow = true; 927 return max_value; 928 } 929 if (r < 0 && l < min_value - r) { 930 *overflow = true; 931 return min_value; 932 } 933 return l + r; 934 case MINUS: 935 if (r > 0 && l < min_value + r) { 936 *overflow = true; 937 return min_value; 938 } 939 if (r < 0 && l > max_value + r) { 940 *overflow = true; 941 return max_value; 942 } 943 return l - r; 944 case SHL: 945 /* TODO: warn about out-of-bounds 'r'. */ 946 /* TODO: warn about overflow. */ 947 return l << (r & 63); 948 case SHR: 949 /* TODO: warn about out-of-bounds 'r'. */ 950 if (l < 0) 951 return (int64_t)~(~(uint64_t)l >> (r & 63)); 952 return (int64_t)((uint64_t)l >> (r & 63)); 953 case LT: 954 return l < r ? 1 : 0; 955 case LE: 956 return l <= r ? 1 : 0; 957 case GT: 958 return l > r ? 1 : 0; 959 case GE: 960 return l >= r ? 1 : 0; 961 case EQ: 962 return l == r ? 1 : 0; 963 case NE: 964 return l != r ? 1 : 0; 965 case BITAND: 966 return l & r; 967 case BITXOR: 968 return l ^ r; 969 case BITOR: 970 return l | r; 971 default: 972 lint_assert(/*CONSTCOND*/false); 973 /* NOTREACHED */ 974 } 975 } 976 977 static tnode_t * 978 fold_constant_integer(tnode_t *tn) 979 { 980 981 lint_assert(has_operands(tn)); 982 tspec_t t = tn->u.ops.left->tn_type->t_tspec; 983 int64_t l = tn->u.ops.left->u.value.u.integer; 984 int64_t r = is_binary(tn) ? tn->u.ops.right->u.value.u.integer : 0; 985 uint64_t mask = value_bits(size_in_bits(t)); 986 987 int64_t res; 988 bool overflow = false; 989 if (!is_integer(t) || is_uinteger(t)) { 990 uint64_t u_res = fold_unsigned_integer(tn->tn_op, 991 (uint64_t)l, (uint64_t)r, mask, &overflow); 992 if (u_res > mask) 993 overflow = true; 994 res = (int64_t)u_res; 995 if (overflow && hflag) { 996 char buf[128]; 997 if (is_binary(tn)) { 998 snprintf(buf, sizeof(buf), "%ju %s %ju", 999 (uintmax_t)l, op_name(tn->tn_op), 1000 (uintmax_t)r); 1001 } else { 1002 snprintf(buf, sizeof(buf), "%s%ju", 1003 op_name(tn->tn_op), (uintmax_t)l); 1004 } 1005 /* '%s' overflows '%s' */ 1006 warning(141, buf, type_name(tn->tn_type)); 1007 } 1008 } else { 1009 int64_t max_value = (int64_t)(mask >> 1); 1010 int64_t min_value = -max_value - 1; 1011 res = fold_signed_integer(tn->tn_op, 1012 l, r, min_value, max_value, &overflow); 1013 if (res < min_value || res > max_value) 1014 overflow = true; 1015 if (overflow && hflag) { 1016 char buf[128]; 1017 if (is_binary(tn)) { 1018 snprintf(buf, sizeof(buf), "%jd %s %jd", 1019 (intmax_t)l, op_name(tn->tn_op), 1020 (intmax_t)r); 1021 } else if (tn->tn_op == UMINUS && l < 0) { 1022 snprintf(buf, sizeof(buf), "-(%jd)", 1023 (intmax_t)l); 1024 } else { 1025 snprintf(buf, sizeof(buf), "%s%jd", 1026 op_name(tn->tn_op), (intmax_t)l); 1027 } 1028 /* '%s' overflows '%s' */ 1029 warning(141, buf, type_name(tn->tn_type)); 1030 } 1031 } 1032 1033 val_t *v = xcalloc(1, sizeof(*v)); 1034 v->v_tspec = tn->tn_type->t_tspec; 1035 v->u.integer = convert_integer(res, t, size_in_bits(t)); 1036 1037 tnode_t *cn = build_constant(tn->tn_type, v); 1038 if (tn->u.ops.left->tn_system_dependent) 1039 cn->tn_system_dependent = true; 1040 if (is_binary(tn) && tn->u.ops.right->tn_system_dependent) 1041 cn->tn_system_dependent = true; 1042 1043 return cn; 1044 } 1045 1046 static tnode_t * 1047 build_struct_access(op_t op, bool sys, tnode_t *ln, tnode_t *rn) 1048 { 1049 1050 lint_assert(rn->tn_op == NAME); 1051 lint_assert(is_member(rn->u.sym)); 1052 1053 bool lvalue = op == ARROW || ln->tn_lvalue; 1054 1055 if (op == POINT) 1056 ln = build_address(sys, ln, true); 1057 else if (ln->tn_type->t_tspec != PTR) { 1058 lint_assert(!allow_c90); 1059 lint_assert(is_integer(ln->tn_type->t_tspec)); 1060 ln = convert(NOOP, 0, expr_derive_type(gettyp(VOID), PTR), ln); 1061 } 1062 1063 tnode_t *ctn = build_integer_constant(PTRDIFF_TSPEC, 1064 rn->u.sym->u.s_member.sm_offset_in_bits / CHAR_SIZE); 1065 1066 type_t *ptr_tp = expr_derive_type(rn->tn_type, PTR); 1067 tnode_t *ntn = build_op(PLUS, sys, ptr_tp, ln, ctn); 1068 if (ln->tn_op == CON) 1069 ntn = fold_constant_integer(ntn); 1070 1071 op_t nop = rn->tn_type->t_bitfield ? FSEL : INDIR; 1072 ntn = build_op(nop, sys, ntn->tn_type->t_subt, ntn, NULL); 1073 if (!lvalue) 1074 ntn->tn_lvalue = false; 1075 1076 return ntn; 1077 } 1078 1079 /* 1080 * Get the size in bytes of type tp->t_subt, as a constant expression of type 1081 * ptrdiff_t as seen from the target platform. 1082 */ 1083 static tnode_t * 1084 subt_size_in_bytes(type_t *tp) 1085 { 1086 1087 lint_assert(tp->t_tspec == PTR); 1088 tp = tp->t_subt; 1089 1090 int elem = 1; 1091 while (tp->t_tspec == ARRAY) { 1092 elem *= tp->u.dimension; 1093 tp = tp->t_subt; 1094 } 1095 1096 int elsz_in_bits = 0; 1097 switch (tp->t_tspec) { 1098 case FUNC: 1099 /* pointer to function is not allowed here */ 1100 error(110); 1101 break; 1102 case VOID: 1103 /* cannot do pointer arithmetic on operand of unknown size */ 1104 gnuism(136); 1105 break; 1106 case STRUCT: 1107 case UNION: 1108 if ((elsz_in_bits = (int)tp->u.sou->sou_size_in_bits) == 0) 1109 /* cannot do pointer arithmetic on operand of ... */ 1110 error(136); 1111 break; 1112 case ENUM: 1113 if (is_incomplete(tp)) 1114 /* cannot do pointer arithmetic on operand of ... */ 1115 warning(136); 1116 /* FALLTHROUGH */ 1117 default: 1118 if ((elsz_in_bits = size_in_bits(tp->t_tspec)) == 0) 1119 /* cannot do pointer arithmetic on operand of ... */ 1120 error(136); 1121 else 1122 lint_assert(elsz_in_bits != -1); 1123 break; 1124 } 1125 1126 if (elem == 0 && elsz_in_bits != 0) 1127 /* cannot do pointer arithmetic on operand of unknown size */ 1128 error(136); 1129 1130 if (elsz_in_bits == 0) 1131 elsz_in_bits = CHAR_SIZE; 1132 1133 return build_integer_constant(PTRDIFF_TSPEC, 1134 (int64_t)(elem * elsz_in_bits / CHAR_SIZE)); 1135 } 1136 1137 static tnode_t * 1138 build_prepost_incdec(op_t op, bool sys, tnode_t *ln) 1139 { 1140 1141 lint_assert(ln != NULL); 1142 tnode_t *cn = ln->tn_type->t_tspec == PTR 1143 ? subt_size_in_bytes(ln->tn_type) 1144 : build_integer_constant(INT, 1); 1145 return build_op(op, sys, ln->tn_type, ln, cn); 1146 } 1147 1148 static void 1149 check_enum_array_index(const tnode_t *ln, const tnode_t *rn) 1150 { 1151 1152 if (ln->tn_op != ADDR || ln->u.ops.left->tn_op != NAME) 1153 return; 1154 1155 const type_t *ltp = ln->u.ops.left->tn_type; 1156 if (ltp->t_tspec != ARRAY || ltp->t_incomplete_array) 1157 return; 1158 1159 if (rn->tn_op != CVT || !rn->tn_type->t_is_enum) 1160 return; 1161 if (rn->u.ops.left->tn_op != LOAD) 1162 return; 1163 1164 const type_t *rtp = rn->u.ops.left->tn_type; 1165 const sym_t *ec = rtp->u.enumer->en_first_enumerator; 1166 const sym_t *max_ec = ec; 1167 lint_assert(ec != NULL); 1168 for (ec = ec->s_next; ec != NULL; ec = ec->s_next) 1169 if (ec->u.s_enum_constant > max_ec->u.s_enum_constant) 1170 max_ec = ec; 1171 1172 int64_t max_enum_value = max_ec->u.s_enum_constant; 1173 lint_assert(INT_MIN <= max_enum_value && max_enum_value <= INT_MAX); 1174 1175 int max_array_index = ltp->u.dimension - 1; 1176 if (max_enum_value == max_array_index) 1177 return; 1178 1179 if (max_enum_value == max_array_index + 1 && 1180 (strstr(max_ec->s_name, "MAX") != NULL || 1181 strstr(max_ec->s_name, "max") != NULL || 1182 strstr(max_ec->s_name, "NUM") != NULL || 1183 strstr(max_ec->s_name, "num") != NULL)) 1184 return; 1185 1186 /* maximum value %d of '%s' does not match maximum array index %d */ 1187 warning(348, (int)max_enum_value, type_name(rtp), max_array_index); 1188 print_previous_declaration(max_ec); 1189 } 1190 1191 static tnode_t * 1192 build_plus_minus(op_t op, bool sys, tnode_t *ln, tnode_t *rn) 1193 { 1194 1195 if (rn->tn_type->t_tspec == PTR && is_integer(ln->tn_type->t_tspec)) { 1196 tnode_t *tmp = ln; 1197 ln = rn; 1198 rn = tmp; 1199 /* pointer addition has integer on the left-hand side */ 1200 query_message(5); 1201 } 1202 1203 /* pointer +- integer */ 1204 tspec_t lt = ln->tn_type->t_tspec; 1205 tspec_t rt = rn->tn_type->t_tspec; 1206 if (lt == PTR && rt != PTR) { 1207 lint_assert(is_integer(rt)); 1208 1209 check_ctype_macro_invocation(ln, rn); 1210 check_enum_array_index(ln, rn); 1211 1212 tnode_t *elsz = subt_size_in_bytes(ln->tn_type); 1213 tspec_t szt = elsz->tn_type->t_tspec; 1214 if (rt != szt && rt != unsigned_type(szt)) 1215 rn = convert(NOOP, 0, elsz->tn_type, rn); 1216 1217 tnode_t *prod = build_op(MULT, sys, rn->tn_type, rn, elsz); 1218 if (rn->tn_op == CON) 1219 prod = fold_constant_integer(prod); 1220 1221 return build_op(op, sys, ln->tn_type, ln, prod); 1222 } 1223 1224 /* pointer - pointer */ 1225 if (rt == PTR) { 1226 lint_assert(lt == PTR); 1227 lint_assert(op == MINUS); 1228 1229 type_t *ptrdiff = gettyp(PTRDIFF_TSPEC); 1230 tnode_t *raw_diff = build_op(op, sys, ptrdiff, ln, rn); 1231 if (ln->tn_op == CON && rn->tn_op == CON) 1232 raw_diff = fold_constant_integer(raw_diff); 1233 1234 tnode_t *elsz = subt_size_in_bytes(ln->tn_type); 1235 balance(NOOP, &raw_diff, &elsz); 1236 1237 return build_op(DIV, sys, ptrdiff, raw_diff, elsz); 1238 } 1239 1240 return build_op(op, sys, ln->tn_type, ln, rn); 1241 } 1242 1243 static tnode_t * 1244 build_bit_shift(op_t op, bool sys, tnode_t *ln, tnode_t *rn) 1245 { 1246 1247 if (!allow_c90 && rn->tn_type->t_tspec != INT) 1248 // XXX: C1978 7.5 says: "Both [operators] perform the usual 1249 // arithmetic conversions on their operands." 1250 // TODO: Add a test to exercise this part of the code. 1251 rn = convert(NOOP, 0, gettyp(INT), rn); 1252 return build_op(op, sys, ln->tn_type, ln, rn); 1253 } 1254 1255 static bool 1256 is_null_pointer(const tnode_t *tn) 1257 { 1258 tspec_t t = tn->tn_type->t_tspec; 1259 1260 // TODO: Investigate how other pointers are stored, in particular, 1261 // whether a pointer constant can have a non-zero value. 1262 // If not, simplify the code below. 1263 return ((t == PTR && tn->tn_type->t_subt->t_tspec == VOID) 1264 || is_integer(t)) 1265 && (tn->tn_op == CON && tn->u.value.u.integer == 0); 1266 } 1267 1268 /* Return a type based on tp1, with added qualifiers from tp2. */ 1269 static type_t * 1270 merge_qualifiers(type_t *tp1, const type_t *tp2) 1271 { 1272 1273 lint_assert(tp1->t_tspec == PTR); 1274 lint_assert(tp2->t_tspec == PTR); 1275 1276 bool c1 = tp1->t_subt->t_const; 1277 bool c2 = tp2->t_subt->t_const; 1278 bool v1 = tp1->t_subt->t_volatile; 1279 bool v2 = tp2->t_subt->t_volatile; 1280 1281 if (c1 == (c1 | c2) && v1 == (v1 | v2)) 1282 return tp1; 1283 1284 type_t *nstp = expr_dup_type(tp1->t_subt); 1285 nstp->t_const |= c2; 1286 nstp->t_volatile |= v2; 1287 1288 type_t *ntp = expr_dup_type(tp1); 1289 ntp->t_subt = nstp; 1290 return ntp; 1291 } 1292 1293 /* See C99 6.5.15 "Conditional operator". */ 1294 static tnode_t * 1295 build_colon(bool sys, tnode_t *ln, tnode_t *rn) 1296 { 1297 tspec_t lt = ln->tn_type->t_tspec; 1298 tspec_t rt = rn->tn_type->t_tspec; 1299 1300 type_t *tp; 1301 if (is_arithmetic(lt) && is_arithmetic(rt)) 1302 /* The operands were already balanced in build_binary. */ 1303 tp = ln->tn_type; 1304 else if (lt == BOOL && rt == BOOL) 1305 tp = ln->tn_type; 1306 else if (lt == VOID || rt == VOID) 1307 tp = gettyp(VOID); 1308 else if (is_struct_or_union(lt)) { 1309 lint_assert(is_struct_or_union(rt)); 1310 lint_assert(ln->tn_type->u.sou == rn->tn_type->u.sou); 1311 if (is_incomplete(ln->tn_type)) { 1312 /* unknown operand size, op '%s' */ 1313 error(138, op_name(COLON)); 1314 return NULL; 1315 } 1316 tp = ln->tn_type; 1317 } else if (lt == PTR && is_integer(rt)) { 1318 if (rt != PTRDIFF_TSPEC) 1319 rn = convert(NOOP, 0, gettyp(PTRDIFF_TSPEC), rn); 1320 tp = ln->tn_type; 1321 } else if (rt == PTR && is_integer(lt)) { 1322 if (lt != PTRDIFF_TSPEC) 1323 ln = convert(NOOP, 0, gettyp(PTRDIFF_TSPEC), ln); 1324 tp = rn->tn_type; 1325 } else if (lt == PTR && is_null_pointer(rn)) 1326 tp = merge_qualifiers(ln->tn_type, rn->tn_type); 1327 else if (rt == PTR && is_null_pointer(ln)) 1328 tp = merge_qualifiers(rn->tn_type, ln->tn_type); 1329 else if (lt == PTR && ln->tn_type->t_subt->t_tspec == VOID) 1330 tp = merge_qualifiers(ln->tn_type, rn->tn_type); 1331 else if (rt == PTR && rn->tn_type->t_subt->t_tspec == VOID) 1332 tp = merge_qualifiers(rn->tn_type, ln->tn_type); 1333 else { 1334 /* 1335 * XXX For now we simply take the left type. This is probably 1336 * wrong, if one type contains a function prototype and the 1337 * other one, at the same place, only an old-style declaration. 1338 */ 1339 tp = merge_qualifiers(ln->tn_type, rn->tn_type); 1340 } 1341 1342 return build_op(COLON, sys, tp, ln, rn); 1343 } 1344 1345 /* TODO: check for varargs */ 1346 static bool 1347 is_cast_redundant(const tnode_t *tn) 1348 { 1349 const type_t *ntp = tn->tn_type, *otp = tn->u.ops.left->tn_type; 1350 tspec_t nt = ntp->t_tspec, ot = otp->t_tspec; 1351 1352 if (nt == BOOL || ot == BOOL) 1353 return nt == BOOL && ot == BOOL; 1354 1355 if (is_integer(nt) && is_integer(ot)) { 1356 unsigned int nw = width_in_bits(ntp), ow = width_in_bits(otp); 1357 if (is_uinteger(nt) == is_uinteger(ot)) 1358 return nw >= ow; 1359 return is_uinteger(ot) && nw > ow; 1360 } 1361 1362 if (is_complex(nt) || is_complex(ot)) 1363 return is_complex(nt) && is_complex(ot) && 1364 size_in_bits(nt) >= size_in_bits(ot); 1365 1366 if (is_floating(nt) && is_floating(ot)) 1367 return size_in_bits(nt) >= size_in_bits(ot); 1368 1369 if (nt == PTR && ot == PTR) { 1370 if (!ntp->t_subt->t_const && otp->t_subt->t_const) 1371 return false; 1372 if (!ntp->t_subt->t_volatile && otp->t_subt->t_volatile) 1373 return false; 1374 1375 if (ntp->t_subt->t_tspec == VOID || 1376 otp->t_subt->t_tspec == VOID || 1377 types_compatible(ntp->t_subt, otp->t_subt, 1378 false, false, NULL)) 1379 return true; 1380 } 1381 1382 return false; 1383 } 1384 1385 static bool 1386 is_assignment(op_t op) 1387 { 1388 1389 return op == ASSIGN || 1390 op == MULASS || 1391 op == DIVASS || 1392 op == MODASS || 1393 op == ADDASS || 1394 op == SUBASS || 1395 op == SHLASS || 1396 op == SHRASS || 1397 op == ANDASS || 1398 op == XORASS || 1399 op == ORASS || 1400 op == RETURN || 1401 op == INIT; 1402 } 1403 1404 static tnode_t * 1405 build_assignment(op_t op, bool sys, tnode_t *ln, tnode_t *rn) 1406 { 1407 1408 tspec_t lt = ln->tn_type->t_tspec; 1409 tspec_t rt = rn->tn_type->t_tspec; 1410 1411 if (any_query_enabled && is_assignment(rn->tn_op)) { 1412 /* chained assignment with '%s' and '%s' */ 1413 query_message(10, op_name(op), op_name(rn->tn_op)); 1414 } 1415 1416 if ((op == ADDASS || op == SUBASS) && lt == PTR) { 1417 lint_assert(is_integer(rt)); 1418 tnode_t *ctn = subt_size_in_bytes(ln->tn_type); 1419 if (rn->tn_type->t_tspec != ctn->tn_type->t_tspec) 1420 rn = convert(NOOP, 0, ctn->tn_type, rn); 1421 rn = build_op(MULT, sys, rn->tn_type, rn, ctn); 1422 if (rn->u.ops.left->tn_op == CON) 1423 rn = fold_constant_integer(rn); 1424 } 1425 1426 if ((op == ASSIGN || op == RETURN || op == INIT) && 1427 (lt == STRUCT || rt == STRUCT)) { 1428 lint_assert(lt == rt); 1429 lint_assert(ln->tn_type->u.sou == rn->tn_type->u.sou); 1430 if (is_incomplete(ln->tn_type)) { 1431 if (op == RETURN) 1432 /* cannot return incomplete type */ 1433 error(212); 1434 else 1435 /* unknown operand size, op '%s' */ 1436 error(138, op_name(op)); 1437 return NULL; 1438 } 1439 } 1440 1441 if (op == SHLASS && hflag && allow_trad && allow_c90 1442 && portable_rank_cmp(lt, rt) < 0) 1443 /* semantics of '%s' change in C90; ... */ 1444 warning(118, "<<="); 1445 1446 if (op != SHLASS && op != SHRASS 1447 && (op == ASSIGN || lt != PTR) 1448 && (lt != rt || (ln->tn_type->t_bitfield && rn->tn_op == CON))) { 1449 rn = convert(op, 0, ln->tn_type, rn); 1450 rt = lt; 1451 } 1452 1453 if (is_query_enabled[20] 1454 && lt == PTR && ln->tn_type->t_subt->t_tspec != VOID 1455 && rt == PTR && rn->tn_type->t_subt->t_tspec == VOID 1456 && !is_null_pointer(rn)) 1457 /* implicit narrowing conversion from void ... */ 1458 query_message(20, type_name(ln->tn_type)); 1459 1460 if (any_query_enabled && rn->tn_op == CVT && rn->tn_cast && 1461 types_compatible(ln->tn_type, rn->tn_type, false, false, NULL) && 1462 is_cast_redundant(rn)) { 1463 /* redundant cast from '%s' to '%s' before assignment */ 1464 query_message(7, type_name(rn->u.ops.left->tn_type), 1465 type_name(rn->tn_type)); 1466 } 1467 1468 return build_op(op, sys, ln->tn_type, ln, rn); 1469 } 1470 1471 static tnode_t * 1472 build_real_imag(op_t op, bool sys, tnode_t *ln) 1473 { 1474 1475 lint_assert(ln != NULL); 1476 if (ln->tn_op == NAME) { 1477 /* 1478 * This may be too much, but it avoids wrong warnings. See 1479 * d_c99_complex_split.c. 1480 */ 1481 mark_as_used(ln->u.sym, false, false); 1482 mark_as_set(ln->u.sym); 1483 } 1484 1485 tspec_t t; 1486 switch (ln->tn_type->t_tspec) { 1487 case LCOMPLEX: 1488 t = LDOUBLE; 1489 break; 1490 case DCOMPLEX: 1491 t = DOUBLE; 1492 break; 1493 case FCOMPLEX: 1494 t = FLOAT; 1495 break; 1496 default: 1497 /* '__%s__' is illegal for type '%s' */ 1498 error(276, op == REAL ? "real" : "imag", 1499 type_name(ln->tn_type)); 1500 return NULL; 1501 } 1502 1503 tnode_t *ntn = build_op(op, sys, gettyp(t), ln, NULL); 1504 ntn->tn_lvalue = true; 1505 return ntn; 1506 } 1507 1508 static bool 1509 is_confusing_precedence(op_t op, op_t lop, bool lparen, op_t rop, bool rparen) 1510 { 1511 1512 if (op == SHL || op == SHR) { 1513 if (!lparen && (lop == PLUS || lop == MINUS)) 1514 return true; 1515 if (!rparen && (rop == PLUS || rop == MINUS)) 1516 return true; 1517 return false; 1518 } 1519 1520 if (op == LOGOR) { 1521 if (!lparen && lop == LOGAND) 1522 return true; 1523 if (!rparen && rop == LOGAND) 1524 return true; 1525 return false; 1526 } 1527 1528 lint_assert(op == BITAND || op == BITXOR || op == BITOR); 1529 if (!lparen && lop != op) { 1530 if (lop == PLUS || lop == MINUS) 1531 return true; 1532 if (lop == BITAND || lop == BITXOR) 1533 return true; 1534 } 1535 if (!rparen && rop != op) { 1536 if (rop == PLUS || rop == MINUS) 1537 return true; 1538 if (rop == BITAND || rop == BITXOR) 1539 return true; 1540 } 1541 return false; 1542 } 1543 1544 /* 1545 * Print a warning if the given node has operands which should be 1546 * parenthesized. 1547 * 1548 * XXX Does not work if an operand is a constant expression. Constant 1549 * expressions are already folded. 1550 */ 1551 static void 1552 check_precedence_confusion(tnode_t *tn) 1553 { 1554 tnode_t *ln, *rn; 1555 1556 if (!hflag) 1557 return; 1558 1559 debug_node(tn); 1560 1561 lint_assert(is_binary(tn)); 1562 for (ln = tn->u.ops.left; ln->tn_op == CVT; ln = ln->u.ops.left) 1563 continue; 1564 for (rn = tn->u.ops.right; rn->tn_op == CVT; rn = rn->u.ops.left) 1565 continue; 1566 1567 if (is_confusing_precedence(tn->tn_op, 1568 ln->tn_op, ln->tn_parenthesized, 1569 rn->tn_op, rn->tn_parenthesized)) { 1570 /* precedence confusion possible: parenthesize! */ 1571 warning(169); 1572 } 1573 } 1574 1575 static tnode_t * 1576 fold_constant_compare_zero(tnode_t *tn) 1577 { 1578 1579 val_t *v = xcalloc(1, sizeof(*v)); 1580 v->v_tspec = tn->tn_type->t_tspec; 1581 lint_assert(v->v_tspec == INT || (Tflag && v->v_tspec == BOOL)); 1582 1583 lint_assert(has_operands(tn)); 1584 bool l = constant_is_nonzero(tn->u.ops.left); 1585 bool r = is_binary(tn) && constant_is_nonzero(tn->u.ops.right); 1586 1587 switch (tn->tn_op) { 1588 case NOT: 1589 if (hflag && !suppress_constcond) 1590 /* constant operand to '!' */ 1591 warning(239); 1592 v->u.integer = !l ? 1 : 0; 1593 break; 1594 case LOGAND: 1595 v->u.integer = l && r ? 1 : 0; 1596 break; 1597 case LOGOR: 1598 v->u.integer = l || r ? 1 : 0; 1599 break; 1600 default: 1601 lint_assert(/*CONSTCOND*/false); 1602 } 1603 1604 return build_constant(tn->tn_type, v); 1605 } 1606 1607 static long double 1608 floating_error_value(tspec_t t, long double lv) 1609 { 1610 if (t == FLOAT) 1611 return lv < 0 ? -FLT_MAX : FLT_MAX; 1612 if (t == DOUBLE) 1613 return lv < 0 ? -DBL_MAX : DBL_MAX; 1614 /* 1615 * When NetBSD is cross-built in MKLINT=yes mode on x86_64 for sparc64, 1616 * tools/lint checks this code while building usr.bin/xlint. In that 1617 * situation, lint uses the preprocessor for sparc64, in which the type 1618 * 'long double' is IEEE-754-binary128, affecting the macro LDBL_MAX 1619 * below. The type 'long double', as well as the strtold 1620 * implementation, comes from the host platform x86_64 though, where 1621 * 'long double' consumes 128 bits as well but only uses 80 of them. 1622 * The exponent range of the two 'long double' types is the same, but 1623 * the maximum finite value differs due to the extended precision on 1624 * sparc64. 1625 * 1626 * To properly handle the data types of the target platform, lint would 1627 * have to implement the floating-point types in a platform-independent 1628 * way, which is not worth the effort, given how few programs 1629 * practically use 'long double'. 1630 */ 1631 /* LINTED 248: floating-point constant out of range */ 1632 long double max = LDBL_MAX; 1633 return lv < 0 ? -max : max; 1634 } 1635 1636 static bool 1637 is_floating_overflow(tspec_t t, long double val) 1638 { 1639 if (fpe != 0 || isfinite(val) == 0) 1640 return true; 1641 if (t == FLOAT && (val > FLT_MAX || val < -FLT_MAX)) 1642 return true; 1643 if (t == DOUBLE && (val > DBL_MAX || val < -DBL_MAX)) 1644 return true; 1645 return false; 1646 } 1647 1648 static tnode_t * 1649 fold_constant_floating(tnode_t *tn) 1650 { 1651 1652 fpe = 0; 1653 1654 tspec_t t = tn->tn_type->t_tspec; 1655 1656 val_t *v = xcalloc(1, sizeof(*v)); 1657 v->v_tspec = t; 1658 1659 lint_assert(is_floating(t)); 1660 lint_assert(has_operands(tn)); 1661 lint_assert(t == tn->u.ops.left->tn_type->t_tspec); 1662 lint_assert(!is_binary(tn) || t == tn->u.ops.right->tn_type->t_tspec); 1663 1664 long double lv = tn->u.ops.left->u.value.u.floating; 1665 long double rv = is_binary(tn) ? tn->u.ops.right->u.value.u.floating 1666 : 0.0; 1667 1668 switch (tn->tn_op) { 1669 case UPLUS: 1670 v->u.floating = lv; 1671 break; 1672 case UMINUS: 1673 v->u.floating = -lv; 1674 break; 1675 case MULT: 1676 v->u.floating = lv * rv; 1677 break; 1678 case DIV: 1679 if (rv == 0.0) { 1680 /* division by 0 */ 1681 error(139); 1682 v->u.floating = floating_error_value(t, lv); 1683 } else { 1684 v->u.floating = lv / rv; 1685 } 1686 break; 1687 case PLUS: 1688 v->u.floating = lv + rv; 1689 break; 1690 case MINUS: 1691 v->u.floating = lv - rv; 1692 break; 1693 case LT: 1694 v->u.integer = lv < rv ? 1 : 0; 1695 break; 1696 case LE: 1697 v->u.integer = lv <= rv ? 1 : 0; 1698 break; 1699 case GE: 1700 v->u.integer = lv >= rv ? 1 : 0; 1701 break; 1702 case GT: 1703 v->u.integer = lv > rv ? 1 : 0; 1704 break; 1705 case EQ: 1706 v->u.integer = lv == rv ? 1 : 0; 1707 break; 1708 case NE: 1709 v->u.integer = lv != rv ? 1 : 0; 1710 break; 1711 default: 1712 lint_assert(/*CONSTCOND*/false); 1713 } 1714 1715 // XXX: Must not access u.floating after setting u.integer. 1716 lint_assert(fpe != 0 || isnan(v->u.floating) == 0); 1717 if (is_complex(v->v_tspec)) { 1718 /* 1719 * Don't warn, as lint doesn't model the imaginary part of 1720 * complex numbers. 1721 */ 1722 fpe = 0; 1723 } else if (is_floating_overflow(t, v->u.floating)) { 1724 /* operator '%s' produces floating point overflow */ 1725 warning(142, op_name(tn->tn_op)); 1726 v->u.floating = floating_error_value(t, v->u.floating); 1727 fpe = 0; 1728 } 1729 1730 return build_constant(tn->tn_type, v); 1731 } 1732 1733 static void 1734 use(const tnode_t *tn) 1735 { 1736 if (tn == NULL) 1737 return; 1738 switch (tn->tn_op) { 1739 case NAME: 1740 mark_as_used(tn->u.sym, false /* XXX */, false /* XXX */); 1741 break; 1742 case CON: 1743 case STRING: 1744 break; 1745 case CALL:; 1746 const function_call *call = tn->u.call; 1747 for (size_t i = 0, n = call->args_len; i < n; i++) 1748 use(call->args[i]); 1749 break; 1750 default: 1751 lint_assert(has_operands(tn)); 1752 use(tn->u.ops.left); 1753 if (is_binary(tn)) 1754 use(tn->u.ops.right); 1755 } 1756 } 1757 1758 /* 1759 * Create a tree node for a binary operator and its two operands. Also called 1760 * for unary operators; in that case rn is NULL. 1761 * 1762 * Function calls, sizeof and casts are handled elsewhere. 1763 */ 1764 tnode_t * 1765 build_binary(tnode_t *ln, op_t op, bool sys, tnode_t *rn) 1766 { 1767 const mod_t *mp = &modtab[op]; 1768 1769 /* If there was an error in one of the operands, return. */ 1770 if (ln == NULL || (mp->m_binary && rn == NULL)) 1771 return NULL; 1772 1773 if (mp->m_value_context || mp->m_compares_with_zero) 1774 ln = cconv(ln); 1775 if (mp->m_binary && op != ARROW && op != POINT) 1776 rn = cconv(rn); 1777 1778 if (mp->m_comparison) 1779 check_integer_comparison(op, ln, rn); 1780 1781 if (mp->m_value_context || mp->m_compares_with_zero) 1782 ln = promote(op, false, ln); 1783 if (mp->m_binary && op != ARROW && op != POINT && 1784 op != ASSIGN && op != RETURN && op != INIT) 1785 rn = promote(op, false, rn); 1786 1787 if (mp->m_warn_if_left_unsigned_in_c90 && 1788 ln->tn_op == CON && ln->u.value.v_unsigned_since_c90) { 1789 /* C90 treats constant as unsigned, op '%s' */ 1790 warning(218, op_name(op)); 1791 ln->u.value.v_unsigned_since_c90 = false; 1792 } 1793 if (mp->m_warn_if_right_unsigned_in_c90 && 1794 rn->tn_op == CON && rn->u.value.v_unsigned_since_c90) { 1795 /* C90 treats constant as unsigned, op '%s' */ 1796 warning(218, op_name(op)); 1797 rn->u.value.v_unsigned_since_c90 = false; 1798 } 1799 1800 if (mp->m_balance_operands || (!allow_c90 && (op == SHL || op == SHR))) 1801 balance(op, &ln, &rn); 1802 1803 if (!typeok(op, 0, ln, rn)) 1804 return NULL; 1805 1806 tnode_t *ntn; 1807 switch (op) { 1808 case POINT: 1809 case ARROW: 1810 ntn = build_struct_access(op, sys, ln, rn); 1811 break; 1812 case INCAFT: 1813 case DECAFT: 1814 case INCBEF: 1815 case DECBEF: 1816 ntn = build_prepost_incdec(op, sys, ln); 1817 break; 1818 case ADDR: 1819 ntn = build_address(sys, ln, false); 1820 break; 1821 case INDIR: 1822 ntn = build_op(INDIR, sys, ln->tn_type->t_subt, ln, NULL); 1823 break; 1824 case PLUS: 1825 case MINUS: 1826 ntn = build_plus_minus(op, sys, ln, rn); 1827 break; 1828 case SHL: 1829 case SHR: 1830 ntn = build_bit_shift(op, sys, ln, rn); 1831 break; 1832 case COLON: 1833 ntn = build_colon(sys, ln, rn); 1834 break; 1835 case ASSIGN: 1836 case MULASS: 1837 case DIVASS: 1838 case MODASS: 1839 case ADDASS: 1840 case SUBASS: 1841 case SHLASS: 1842 case SHRASS: 1843 case ANDASS: 1844 case XORASS: 1845 case ORASS: 1846 case RETURN: 1847 case INIT: 1848 ntn = build_assignment(op, sys, ln, rn); 1849 break; 1850 case COMMA: 1851 if (any_query_enabled) { 1852 /* comma operator with types '%s' and '%s' */ 1853 query_message(12, 1854 type_name(ln->tn_type), type_name(rn->tn_type)); 1855 } 1856 /* FALLTHROUGH */ 1857 case QUEST: 1858 ntn = build_op(op, sys, rn->tn_type, ln, rn); 1859 break; 1860 case REAL: 1861 case IMAG: 1862 ntn = build_real_imag(op, sys, ln); 1863 break; 1864 default: 1865 lint_assert(mp->m_binary == (rn != NULL)); 1866 type_t *rettp = mp->m_returns_bool 1867 ? gettyp(Tflag ? BOOL : INT) : ln->tn_type; 1868 ntn = build_op(op, sys, rettp, ln, rn); 1869 break; 1870 } 1871 1872 if (ntn == NULL) 1873 return NULL; 1874 1875 if (mp->m_possible_precedence_confusion) 1876 check_precedence_confusion(ntn); 1877 1878 if (hflag && !suppress_constcond && 1879 mp->m_compares_with_zero && 1880 (ln->tn_op == CON || 1881 (mp->m_binary && op != QUEST && rn->tn_op == CON)) && 1882 /* XXX: rn->tn_system_dependent should be checked as well */ 1883 !ln->tn_system_dependent) 1884 /* constant in conditional context */ 1885 warning(161); 1886 1887 if (mp->m_fold_constant_operands && ln->tn_op == CON) { 1888 if (!mp->m_binary || rn->tn_op == CON) { 1889 if (mp->m_compares_with_zero) 1890 ntn = fold_constant_compare_zero(ntn); 1891 else if (is_floating(ntn->tn_type->t_tspec)) 1892 ntn = fold_constant_floating(ntn); 1893 else 1894 ntn = fold_constant_integer(ntn); 1895 } else if (op == QUEST) { 1896 lint_assert(has_operands(rn)); 1897 use(ln->u.value.u.integer != 0 1898 ? rn->u.ops.right : rn->u.ops.left); 1899 ntn = ln->u.value.u.integer != 0 1900 ? rn->u.ops.left : rn->u.ops.right; 1901 } 1902 } 1903 1904 return ntn; 1905 } 1906 1907 tnode_t * 1908 build_unary(op_t op, bool sys, tnode_t *tn) 1909 { 1910 return build_binary(tn, op, sys, NULL); 1911 } 1912 1913 static bool 1914 are_members_compatible(const sym_t *a, const sym_t *b) 1915 { 1916 if (a->u.s_member.sm_offset_in_bits != b->u.s_member.sm_offset_in_bits) 1917 return false; 1918 1919 const type_t *atp = a->s_type; 1920 const type_t *btp = b->s_type; 1921 bool w = false; 1922 if (!types_compatible(atp, btp, false, false, &w) && !w) 1923 return false; 1924 if (a->s_bitfield != b->s_bitfield) 1925 return false; 1926 if (a->s_bitfield) { 1927 if (atp->t_bit_field_width != btp->t_bit_field_width) 1928 return false; 1929 if (atp->t_bit_field_offset != btp->t_bit_field_offset) 1930 return false; 1931 } 1932 return true; 1933 } 1934 1935 /* 1936 * Return whether all struct/union members with the same name have the same 1937 * type and offset. 1938 */ 1939 static bool 1940 all_members_compatible(const sym_t *msym) 1941 { 1942 for (const sym_t *csym = msym; 1943 csym != NULL; csym = csym->s_symtab_next) { 1944 if (!is_member(csym)) 1945 continue; 1946 if (strcmp(msym->s_name, csym->s_name) != 0) 1947 continue; 1948 1949 for (const sym_t *sym = csym->s_symtab_next; 1950 sym != NULL; sym = sym->s_symtab_next) { 1951 if (is_member(sym) 1952 && strcmp(csym->s_name, sym->s_name) == 0 1953 && !are_members_compatible(csym, sym)) 1954 return false; 1955 } 1956 } 1957 return true; 1958 } 1959 1960 sym_t * 1961 find_member(const struct_or_union *sou, const char *name) 1962 { 1963 for (sym_t *mem = sou->sou_first_member; 1964 mem != NULL; mem = mem->s_next) { 1965 lint_assert(is_member(mem)); 1966 lint_assert(mem->u.s_member.sm_containing_type == sou); 1967 if (strcmp(mem->s_name, name) == 0) 1968 return mem; 1969 } 1970 1971 for (sym_t *mem = sou->sou_first_member; 1972 mem != NULL; mem = mem->s_next) { 1973 if (is_struct_or_union(mem->s_type->t_tspec) 1974 && mem->s_name == unnamed) { 1975 sym_t *nested_mem = 1976 find_member(mem->s_type->u.sou, name); 1977 if (nested_mem != NULL) 1978 return nested_mem; 1979 } 1980 } 1981 return NULL; 1982 } 1983 1984 /* 1985 * Remove the member if it was unknown until now, which means 1986 * that no defined struct or union has a member with the same name. 1987 */ 1988 static void 1989 remove_unknown_member(tnode_t *tn, sym_t *msym) 1990 { 1991 /* type '%s' does not have member '%s' */ 1992 error(101, type_name(tn->tn_type), msym->s_name); 1993 symtab_remove_forever(msym); 1994 msym->s_kind = SK_MEMBER; 1995 msym->s_scl = STRUCT_MEMBER; 1996 1997 struct_or_union *sou = expr_zero_alloc(sizeof(*sou), 1998 "struct_or_union"); 1999 sou->sou_tag = expr_zero_alloc(sizeof(*sou->sou_tag), "sym"); 2000 sou->sou_tag->s_name = unnamed; 2001 2002 msym->u.s_member.sm_containing_type = sou; 2003 /* 2004 * The member sm_offset_in_bits is not needed here since this symbol 2005 * can only be used for error reporting. 2006 */ 2007 } 2008 2009 /* 2010 * Returns a symbol which has the same name as 'msym' and is a member of the 2011 * struct or union specified by 'tn'. 2012 */ 2013 static sym_t * 2014 struct_or_union_member(tnode_t *tn, op_t op, sym_t *msym) 2015 { 2016 2017 /* Determine the tag type of which msym is expected to be a member. */ 2018 const type_t *tp = NULL; 2019 if (op == POINT && is_struct_or_union(tn->tn_type->t_tspec)) 2020 tp = tn->tn_type; 2021 if (op == ARROW && tn->tn_type->t_tspec == PTR 2022 && is_struct_or_union(tn->tn_type->t_subt->t_tspec)) 2023 tp = tn->tn_type->t_subt; 2024 struct_or_union *sou = tp != NULL ? tp->u.sou : NULL; 2025 2026 if (sou != NULL) { 2027 sym_t *nested_mem = find_member(sou, msym->s_name); 2028 if (nested_mem != NULL) 2029 return nested_mem; 2030 } 2031 2032 if (msym->s_scl == NO_SCL) { 2033 remove_unknown_member(tn, msym); 2034 return msym; 2035 } 2036 2037 bool eq = all_members_compatible(msym); 2038 2039 /* 2040 * Now handle the case in which the left operand refers really to a 2041 * struct/union, but the right operand is not member of it. 2042 */ 2043 if (sou != NULL) { 2044 if (eq && !allow_c90) 2045 /* illegal use of member '%s' */ 2046 warning(102, msym->s_name); 2047 else 2048 /* illegal use of member '%s' */ 2049 error(102, msym->s_name); 2050 return msym; 2051 } 2052 2053 if (eq) { 2054 if (op == POINT) { 2055 if (!allow_c90) 2056 /* left operand of '.' must be struct ... */ 2057 warning(103, type_name(tn->tn_type)); 2058 else 2059 /* left operand of '.' must be struct ... */ 2060 error(103, type_name(tn->tn_type)); 2061 } else { 2062 if (!allow_c90 && tn->tn_type->t_tspec == PTR) 2063 /* left operand of '->' must be pointer ... */ 2064 warning(104, type_name(tn->tn_type)); 2065 else 2066 /* left operand of '->' must be pointer ... */ 2067 error(104, type_name(tn->tn_type)); 2068 } 2069 } else { 2070 if (!allow_c90) 2071 /* non-unique member requires struct/union %s */ 2072 error(105, op == POINT ? "object" : "pointer"); 2073 else 2074 /* unacceptable operand of '%s' */ 2075 error(111, op_name(op)); 2076 } 2077 2078 return msym; 2079 } 2080 2081 tnode_t * 2082 build_member_access(tnode_t *ln, op_t op, bool sys, sbuf_t *member) 2083 { 2084 sym_t *msym; 2085 2086 if (ln == NULL) 2087 return NULL; 2088 2089 if (op == ARROW) 2090 /* must do this before struct_or_union_member is called */ 2091 ln = cconv(ln); 2092 msym = struct_or_union_member(ln, op, getsym(member)); 2093 return build_binary(ln, op, sys, build_name(msym, false)); 2094 } 2095 2096 /* 2097 * Perform class conversions. 2098 * 2099 * Arrays of type T are converted into pointers to type T. 2100 * Functions are converted to pointers to functions. 2101 * Lvalues are converted to rvalues. 2102 * 2103 * C99 6.3 "Conversions" 2104 * C99 6.3.2 "Other operands" 2105 * C99 6.3.2.1 "Lvalues, arrays, and function designators" 2106 */ 2107 tnode_t * 2108 cconv(tnode_t *tn) 2109 { 2110 if (tn->tn_type->t_tspec == ARRAY) { 2111 if (!tn->tn_lvalue) { 2112 /* XXX print correct operator */ 2113 /* %soperand of '%s' must be lvalue */ 2114 gnuism(114, "", op_name(ADDR)); 2115 } 2116 tn = build_op(ADDR, tn->tn_sys, 2117 expr_derive_type(tn->tn_type->t_subt, PTR), tn, NULL); 2118 } 2119 2120 if (tn->tn_type->t_tspec == FUNC) 2121 tn = build_address(tn->tn_sys, tn, true); 2122 2123 if (tn->tn_lvalue) { 2124 type_t *tp = expr_dup_type(tn->tn_type); 2125 /* C99 6.3.2.1p2 sentence 2 says to remove the qualifiers. */ 2126 tp->t_const = tp->t_volatile = false; 2127 tn = build_op(LOAD, tn->tn_sys, tp, tn, NULL); 2128 } 2129 2130 return tn; 2131 } 2132 2133 const tnode_t * 2134 before_conversion(const tnode_t *tn) 2135 { 2136 while (tn->tn_op == CVT && !tn->tn_cast) 2137 tn = tn->u.ops.left; 2138 return tn; 2139 } 2140 2141 /* 2142 * Most errors required by C90 are reported in struct_or_union_member(). 2143 * Here we only check for totally wrong things. 2144 */ 2145 static bool 2146 typeok_point(const tnode_t *ln, const type_t *ltp, tspec_t lt) 2147 { 2148 if (is_struct_or_union(lt)) 2149 return true; 2150 2151 if (lt == FUNC || lt == VOID || ltp->t_bitfield) 2152 goto wrong; 2153 2154 /* 2155 * Some C dialects from before C90 tolerated any lvalue on the 2156 * left-hand side of the '.' operator, allowing things like 'char 2157 * st[100]; st.st_mtime', assuming that the member 'st_mtime' only 2158 * occurred in a single struct; see typeok_arrow. 2159 */ 2160 if (ln->tn_lvalue) 2161 return true; 2162 2163 wrong: 2164 /* With allow_c90 we already got an error */ 2165 if (!allow_c90) 2166 /* unacceptable operand of '%s' */ 2167 error(111, op_name(POINT)); 2168 2169 return false; 2170 } 2171 2172 static bool 2173 typeok_arrow(tspec_t lt) 2174 { 2175 /* 2176 * C1978 Appendix A 14.1 says: <quote>In fact, any lvalue is allowed 2177 * before '.', and that lvalue is then assumed to have the form of the 2178 * structure of which the name of the right is a member. [...] Such 2179 * constructions are non-portable.</quote> 2180 */ 2181 if (lt == PTR || (!allow_c90 && is_integer(lt))) 2182 return true; 2183 2184 /* With allow_c90 we already got an error */ 2185 if (!allow_c90) 2186 /* unacceptable operand of '%s' */ 2187 error(111, op_name(ARROW)); 2188 return false; 2189 } 2190 2191 static bool 2192 typeok_incdec(op_t op, const tnode_t *tn, const type_t *tp) 2193 { 2194 /* operand has scalar type (checked in typeok) */ 2195 if (!tn->tn_lvalue) { 2196 if (tn->tn_op == CVT && tn->tn_cast && 2197 tn->u.ops.left->tn_op == LOAD) 2198 /* a cast does not yield an lvalue */ 2199 error(163); 2200 /* %soperand of '%s' must be lvalue */ 2201 error(114, "", op_name(op)); 2202 return false; 2203 } 2204 if (tp->t_const && allow_c90) 2205 /* %soperand of '%s' must be modifiable lvalue */ 2206 warning(115, "", op_name(op)); 2207 return true; 2208 } 2209 2210 static bool 2211 typeok_address(op_t op, const tnode_t *tn, const type_t *tp, tspec_t t) 2212 { 2213 if (t == ARRAY || t == FUNC) { 2214 /* ok, a warning comes later (in build_address()) */ 2215 } else if (!tn->tn_lvalue) { 2216 if (tn->tn_op == CVT && tn->tn_cast && 2217 tn->u.ops.left->tn_op == LOAD) 2218 /* a cast does not yield an lvalue */ 2219 error(163); 2220 /* %soperand of '%s' must be lvalue */ 2221 error(114, "", op_name(op)); 2222 return false; 2223 } else if (is_scalar(t)) { 2224 if (tp->t_bitfield) { 2225 /* cannot take address of bit-field */ 2226 error(112); 2227 return false; 2228 } 2229 } else if (t != STRUCT && t != UNION) { 2230 /* unacceptable operand of '%s' */ 2231 error(111, op_name(op)); 2232 return false; 2233 } 2234 if (tn->tn_op == NAME && tn->u.sym->s_register) { 2235 /* cannot take address of register '%s' */ 2236 error(113, tn->u.sym->s_name); 2237 return false; 2238 } 2239 return true; 2240 } 2241 2242 static bool 2243 typeok_indir(const type_t *tp, tspec_t t) 2244 { 2245 2246 if (t != PTR) { 2247 /* cannot dereference non-pointer type '%s' */ 2248 error(96, type_name(tp)); 2249 return false; 2250 } 2251 return true; 2252 } 2253 2254 static void 2255 warn_incompatible_types(op_t op, 2256 const type_t *ltp, tspec_t lt, 2257 const type_t *rtp, tspec_t rt) 2258 { 2259 bool binary = modtab[op].m_binary; 2260 2261 if (lt == VOID || (binary && rt == VOID)) { 2262 /* void type illegal in expression */ 2263 error(109); 2264 } else if (op == ASSIGN) 2265 /* cannot assign to '%s' from '%s' */ 2266 error(171, type_name(ltp), type_name(rtp)); 2267 else if (binary) 2268 /* operands of '%s' have incompatible types '%s' and '%s' */ 2269 error(107, op_name(op), type_name(ltp), type_name(rtp)); 2270 else { 2271 lint_assert(rt == NO_TSPEC); 2272 /* operand of '%s' has invalid type '%s' */ 2273 error(108, op_name(op), type_name(ltp)); 2274 } 2275 } 2276 2277 static bool 2278 typeok_plus(op_t op, 2279 const type_t *ltp, tspec_t lt, 2280 const type_t *rtp, tspec_t rt) 2281 { 2282 /* operands have scalar types (checked in typeok) */ 2283 if ((lt == PTR && !is_integer(rt)) || (rt == PTR && !is_integer(lt))) { 2284 warn_incompatible_types(op, ltp, lt, rtp, rt); 2285 return false; 2286 } 2287 return true; 2288 } 2289 2290 static bool 2291 typeok_minus(op_t op, 2292 const type_t *ltp, tspec_t lt, 2293 const type_t *rtp, tspec_t rt) 2294 { 2295 /* operands have scalar types (checked in typeok) */ 2296 if ((lt == PTR && rt != PTR && !is_integer(rt)) || 2297 (lt != PTR && rt == PTR)) { 2298 warn_incompatible_types(op, ltp, lt, rtp, rt); 2299 return false; 2300 } 2301 if (lt == PTR && rt == PTR && 2302 !types_compatible(ltp->t_subt, rtp->t_subt, true, false, NULL)) { 2303 /* illegal pointer subtraction */ 2304 error(116); 2305 } 2306 return true; 2307 } 2308 2309 static void 2310 typeok_shr(op_t op, 2311 const tnode_t *ln, tspec_t lt, 2312 const tnode_t *rn, tspec_t rt) 2313 { 2314 tspec_t olt = before_conversion(ln)->tn_type->t_tspec; 2315 tspec_t ort = before_conversion(rn)->tn_type->t_tspec; 2316 2317 /* operands have integer types (checked in typeok) */ 2318 if (pflag && !is_uinteger(olt)) { 2319 integer_constraints lc = ic_expr(ln); 2320 if (!ic_maybe_signed(ln->tn_type, &lc)) 2321 return; 2322 2323 if (ln->tn_op != CON) 2324 /* bitwise '%s' on signed value possibly nonportable */ 2325 warning(117, op_name(op)); 2326 else if (ln->u.value.u.integer < 0) 2327 /* bitwise '%s' on signed value nonportable */ 2328 warning(120, op_name(op)); 2329 } else if (allow_trad && allow_c90 && 2330 !is_uinteger(olt) && is_uinteger(ort)) { 2331 /* The left operand would become unsigned in traditional C. */ 2332 if (hflag && (ln->tn_op != CON || ln->u.value.u.integer < 0)) { 2333 /* semantics of '%s' change in C90; use ... */ 2334 warning(118, op_name(op)); 2335 } 2336 } else if (allow_trad && allow_c90 && 2337 !is_uinteger(olt) && !is_uinteger(ort) && 2338 portable_rank_cmp(lt, rt) < 0) { 2339 /* 2340 * In traditional C, the left operand would be extended 2341 * (possibly sign-extended) and then shifted. 2342 */ 2343 if (hflag && (ln->tn_op != CON || ln->u.value.u.integer < 0)) { 2344 /* semantics of '%s' change in C90; use ... */ 2345 warning(118, op_name(op)); 2346 } 2347 } 2348 } 2349 2350 static void 2351 typeok_shl(op_t op, tspec_t lt, tspec_t rt) 2352 { 2353 /* 2354 * C90 does not perform balancing for shift operations, but traditional 2355 * C does. If the width of the right operand is greater than the width 2356 * of the left operand, then in traditional C the left operand would be 2357 * extended to the width of the right operand. For SHL this may result 2358 * in different results. 2359 */ 2360 if (portable_rank_cmp(lt, rt) < 0) { 2361 /* 2362 * XXX If both operands are constant, make sure that there is 2363 * really a difference between C90 and traditional C. 2364 */ 2365 if (hflag && allow_trad && allow_c90) 2366 /* semantics of '%s' change in C90; use ... */ 2367 warning(118, op_name(op)); 2368 } 2369 } 2370 2371 static void 2372 typeok_shift(const type_t *ltp, tspec_t lt, const tnode_t *rn, tspec_t rt) 2373 { 2374 if (rn->tn_op != CON) 2375 return; 2376 2377 if (!is_uinteger(rt) && rn->u.value.u.integer < 0) 2378 /* negative shift */ 2379 warning(121); 2380 else if ((uint64_t)rn->u.value.u.integer == size_in_bits(lt)) 2381 /* shift amount %u equals bit-size of '%s' */ 2382 warning(267, (unsigned)rn->u.value.u.integer, type_name(ltp)); 2383 else if ((uint64_t)rn->u.value.u.integer > size_in_bits(lt)) { 2384 /* shift amount %llu is greater than bit-size %llu of '%s' */ 2385 warning(122, (unsigned long long)rn->u.value.u.integer, 2386 (unsigned long long)size_in_bits(lt), 2387 tspec_name(lt)); 2388 } 2389 } 2390 2391 static bool 2392 is_typeok_eq(const tnode_t *ln, tspec_t lt, const tnode_t *rn, tspec_t rt) 2393 { 2394 if (lt == PTR && is_null_pointer(rn)) 2395 return true; 2396 if (rt == PTR && is_null_pointer(ln)) 2397 return true; 2398 return false; 2399 } 2400 2401 static void 2402 warn_incompatible_pointers(op_t op, const type_t *ltp, const type_t *rtp) 2403 { 2404 lint_assert(ltp->t_tspec == PTR); 2405 lint_assert(rtp->t_tspec == PTR); 2406 2407 tspec_t lt = ltp->t_subt->t_tspec; 2408 tspec_t rt = rtp->t_subt->t_tspec; 2409 2410 if (is_struct_or_union(lt) && is_struct_or_union(rt)) { 2411 if (op == RETURN) 2412 /* illegal structure pointer combination */ 2413 warning(244); 2414 else { 2415 /* incompatible structure pointers: '%s' '%s' '%s' */ 2416 warning(245, type_name(ltp), 2417 op_name(op), type_name(rtp)); 2418 } 2419 } else { 2420 if (op == RETURN) 2421 /* illegal combination of '%s' and '%s' */ 2422 warning(184, type_name(ltp), type_name(rtp)); 2423 else { 2424 /* illegal combination of '%s' and '%s', op '%s' */ 2425 warning(124, 2426 type_name(ltp), type_name(rtp), op_name(op)); 2427 } 2428 } 2429 } 2430 2431 static void 2432 check_pointer_comparison(op_t op, const tnode_t *ln, const tnode_t *rn) 2433 { 2434 type_t *ltp = ln->tn_type, *rtp = rn->tn_type; 2435 tspec_t lst = ltp->t_subt->t_tspec, rst = rtp->t_subt->t_tspec; 2436 2437 if (lst == VOID || rst == VOID) { 2438 /* TODO: C99 behaves like C90 here. */ 2439 if (!allow_trad && !allow_c99 && 2440 (lst == FUNC || rst == FUNC)) { 2441 /* (void *)0 is already handled in typeok() */ 2442 const char *lsts, *rsts; 2443 *(lst == FUNC ? &lsts : &rsts) = "function pointer"; 2444 *(lst == VOID ? &lsts : &rsts) = "'void *'"; 2445 /* C90 or later forbid comparison of %s with %s */ 2446 warning(274, lsts, rsts); 2447 } 2448 return; 2449 } 2450 2451 if (!types_compatible(ltp->t_subt, rtp->t_subt, true, false, NULL)) { 2452 warn_incompatible_pointers(op, ltp, rtp); 2453 return; 2454 } 2455 2456 if (lst == FUNC && rst == FUNC) { 2457 /* TODO: C99 behaves like C90 here, see C99 6.5.8p2. */ 2458 if (!allow_trad && !allow_c99 && op != EQ && op != NE) 2459 /* pointers to functions can only be compared ... */ 2460 warning(125); 2461 } 2462 } 2463 2464 static bool 2465 typeok_compare(op_t op, 2466 const tnode_t *ln, const type_t *ltp, tspec_t lt, 2467 const tnode_t *rn, const type_t *rtp, tspec_t rt) 2468 { 2469 if (lt == PTR && rt == PTR) { 2470 check_pointer_comparison(op, ln, rn); 2471 return true; 2472 } 2473 2474 if (lt != PTR && rt != PTR) 2475 return true; 2476 2477 if (!is_integer(lt) && !is_integer(rt)) { 2478 warn_incompatible_types(op, ltp, lt, rtp, rt); 2479 return false; 2480 } 2481 2482 const char *lx = lt == PTR ? "pointer" : "integer"; 2483 const char *rx = rt == PTR ? "pointer" : "integer"; 2484 /* illegal combination of %s '%s' and %s '%s', op '%s' */ 2485 warning(123, lx, type_name(ltp), rx, type_name(rtp), op_name(op)); 2486 return true; 2487 } 2488 2489 static bool 2490 typeok_quest(tspec_t lt, const tnode_t *rn) 2491 { 2492 if (!is_scalar(lt)) { 2493 /* first operand of '?' must have scalar type */ 2494 error(170); 2495 return false; 2496 } 2497 lint_assert(before_conversion(rn)->tn_op == COLON); 2498 return true; 2499 } 2500 2501 static void 2502 typeok_colon_pointer(const type_t *ltp, const type_t *rtp) 2503 { 2504 type_t *lstp = ltp->t_subt; 2505 type_t *rstp = rtp->t_subt; 2506 tspec_t lst = lstp->t_tspec; 2507 tspec_t rst = rstp->t_tspec; 2508 2509 if ((lst == VOID && rst == FUNC) || (lst == FUNC && rst == VOID)) { 2510 /* (void *)0 is handled in typeok_colon */ 2511 /* TODO: C99 behaves like C90 here. */ 2512 if (!allow_trad && !allow_c99) 2513 /* conversion of %s to %s requires a cast, op %s */ 2514 warning(305, "function pointer", "'void *'", 2515 op_name(COLON)); 2516 return; 2517 } 2518 2519 if (pointer_types_are_compatible(lstp, rstp, true)) 2520 return; 2521 if (!types_compatible(lstp, rstp, true, false, NULL)) 2522 warn_incompatible_pointers(COLON, ltp, rtp); 2523 } 2524 2525 static bool 2526 typeok_colon(const tnode_t *ln, const type_t *ltp, tspec_t lt, 2527 const tnode_t *rn, const type_t *rtp, tspec_t rt) 2528 { 2529 2530 if (is_arithmetic(lt) && is_arithmetic(rt)) 2531 return true; 2532 if (lt == BOOL && rt == BOOL) 2533 return true; 2534 2535 if (lt == STRUCT && rt == STRUCT && ltp->u.sou == rtp->u.sou) 2536 return true; 2537 if (lt == UNION && rt == UNION && ltp->u.sou == rtp->u.sou) 2538 return true; 2539 2540 if (lt == PTR && is_null_pointer(rn)) 2541 return true; 2542 if (rt == PTR && is_null_pointer(ln)) 2543 return true; 2544 2545 if ((lt == PTR && is_integer(rt)) || (is_integer(lt) && rt == PTR)) { 2546 const char *lx = lt == PTR ? "pointer" : "integer"; 2547 const char *rx = rt == PTR ? "pointer" : "integer"; 2548 /* illegal combination of %s '%s' and %s '%s', op '%s' */ 2549 warning(123, lx, type_name(ltp), 2550 rx, type_name(rtp), op_name(COLON)); 2551 return true; 2552 } 2553 2554 if (lt == VOID || rt == VOID) { 2555 if (lt != VOID || rt != VOID) 2556 /* incompatible types '%s' and '%s' in conditional */ 2557 warning(126, type_name(ltp), type_name(rtp)); 2558 return true; 2559 } 2560 2561 if (lt == PTR && rt == PTR) { 2562 typeok_colon_pointer(ltp, rtp); 2563 return true; 2564 } 2565 2566 /* incompatible types '%s' and '%s' in conditional */ 2567 error(126, type_name(ltp), type_name(rtp)); 2568 return false; 2569 } 2570 2571 static bool 2572 has_constant_member(const type_t *tp) 2573 { 2574 lint_assert(is_struct_or_union(tp->t_tspec)); 2575 2576 for (sym_t *m = tp->u.sou->sou_first_member; 2577 m != NULL; m = m->s_next) { 2578 const type_t *mtp = m->s_type; 2579 if (mtp->t_const) 2580 return true; 2581 if (is_struct_or_union(mtp->t_tspec) && 2582 has_constant_member(mtp)) 2583 return true; 2584 } 2585 return false; 2586 } 2587 2588 static bool 2589 typeok_assign(op_t op, const tnode_t *ln, const type_t *ltp, tspec_t lt) 2590 { 2591 if (op == RETURN || op == INIT || op == FARG) 2592 return true; 2593 2594 if (!ln->tn_lvalue) { 2595 if (ln->tn_op == CVT && ln->tn_cast && 2596 ln->u.ops.left->tn_op == LOAD) 2597 /* a cast does not yield an lvalue */ 2598 error(163); 2599 /* %soperand of '%s' must be lvalue */ 2600 error(114, "left ", op_name(op)); 2601 return false; 2602 } else if (ltp->t_const 2603 || (is_struct_or_union(lt) && has_constant_member(ltp))) { 2604 if (allow_c90) 2605 /* %soperand of '%s' must be modifiable lvalue */ 2606 warning(115, "left ", op_name(op)); 2607 } 2608 return true; 2609 } 2610 2611 static bool 2612 typeok_scalar(op_t op, const mod_t *mp, 2613 const type_t *ltp, tspec_t lt, 2614 const type_t *rtp, tspec_t rt) 2615 { 2616 if (mp->m_takes_bool && lt == BOOL && rt == BOOL) 2617 return true; 2618 if (mp->m_requires_integer) { 2619 if (!is_integer(lt) || (mp->m_binary && !is_integer(rt))) { 2620 warn_incompatible_types(op, ltp, lt, rtp, rt); 2621 return false; 2622 } 2623 } else if (mp->m_requires_integer_or_complex) { 2624 if ((!is_integer(lt) && !is_complex(lt)) || 2625 (mp->m_binary && (!is_integer(rt) && !is_complex(rt)))) { 2626 warn_incompatible_types(op, ltp, lt, rtp, rt); 2627 return false; 2628 } 2629 } else if (mp->m_requires_scalar) { 2630 if (!is_scalar(lt) || (mp->m_binary && !is_scalar(rt))) { 2631 warn_incompatible_types(op, ltp, lt, rtp, rt); 2632 return false; 2633 } 2634 } else if (mp->m_requires_arith) { 2635 if (!is_arithmetic(lt) || 2636 (mp->m_binary && !is_arithmetic(rt))) { 2637 warn_incompatible_types(op, ltp, lt, rtp, rt); 2638 return false; 2639 } 2640 } 2641 return true; 2642 } 2643 2644 static void 2645 check_assign_void_pointer(op_t op, int arg, 2646 tspec_t lt, tspec_t lst, 2647 tspec_t rt, tspec_t rst) 2648 { 2649 2650 if (!(lt == PTR && rt == PTR && (lst == VOID || rst == VOID))) 2651 return; 2652 /* two pointers, at least one pointer to void */ 2653 2654 /* TODO: C99 behaves like C90 here. */ 2655 if (!(!allow_trad && !allow_c99 && (lst == FUNC || rst == FUNC))) 2656 return; 2657 /* comb. of ptr to func and ptr to void */ 2658 2659 const char *lts, *rts; 2660 *(lst == FUNC ? <s : &rts) = "function pointer"; 2661 *(lst == VOID ? <s : &rts) = "'void *'"; 2662 2663 switch (op) { 2664 case INIT: 2665 case RETURN: 2666 /* conversion of %s to %s requires a cast */ 2667 warning(303, rts, lts); 2668 break; 2669 case FARG: 2670 /* conversion of %s to %s requires a cast, arg #%d */ 2671 warning(304, rts, lts, arg); 2672 break; 2673 default: 2674 /* conversion of %s to %s requires a cast, op %s */ 2675 warning(305, rts, lts, op_name(op)); 2676 break; 2677 } 2678 } 2679 2680 static bool 2681 is_direct_function_call(const tnode_t *tn, const char **out_name) 2682 { 2683 2684 if (tn->tn_op == CALL 2685 && tn->u.call->func->tn_op == ADDR 2686 && tn->u.call->func->u.ops.left->tn_op == NAME) { 2687 *out_name = tn->u.call->func->u.ops.left->u.sym->s_name; 2688 return true; 2689 } 2690 return false; 2691 } 2692 2693 static bool 2694 is_unconst_function(const char *name) 2695 { 2696 2697 return strcmp(name, "memchr") == 0 || 2698 strcmp(name, "strchr") == 0 || 2699 strcmp(name, "strpbrk") == 0 || 2700 strcmp(name, "strrchr") == 0 || 2701 strcmp(name, "strstr") == 0; 2702 } 2703 2704 static bool 2705 is_const_char_pointer(const tnode_t *tn) 2706 { 2707 /* 2708 * For traditional reasons, C99 6.4.5p5 defines that string literals 2709 * have type 'char[]'. They are often implicitly converted to 'char 2710 * *', for example when they are passed as function arguments. 2711 * 2712 * C99 6.4.5p6 further defines that modifying a string that is 2713 * constructed from a string literal invokes undefined behavior. 2714 * 2715 * Out of these reasons, string literals are treated as 'effectively 2716 * const' here. 2717 */ 2718 if (tn->tn_op == CVT && 2719 tn->u.ops.left->tn_op == ADDR && 2720 tn->u.ops.left->u.ops.left->tn_op == STRING) 2721 return true; 2722 2723 const type_t *tp = before_conversion(tn)->tn_type; 2724 return tp->t_tspec == PTR && 2725 tp->t_subt->t_tspec == CHAR && 2726 tp->t_subt->t_const; 2727 } 2728 2729 static bool 2730 is_const_pointer(const tnode_t *tn) 2731 { 2732 const type_t *tp = before_conversion(tn)->tn_type; 2733 return tp->t_tspec == PTR && tp->t_subt->t_const; 2734 } 2735 2736 static void 2737 check_unconst_function(const type_t *lstp, const tnode_t *rn) 2738 { 2739 const char *function_name; 2740 2741 if (lstp->t_tspec == CHAR && !lstp->t_const && 2742 is_direct_function_call(rn, &function_name) && 2743 is_unconst_function(function_name) && 2744 rn->u.call->args_len >= 1 && 2745 is_const_char_pointer(rn->u.call->args[0])) { 2746 /* call to '%s' effectively discards 'const' from argument */ 2747 warning(346, function_name); 2748 } 2749 2750 if (!lstp->t_const && 2751 is_direct_function_call(rn, &function_name) && 2752 strcmp(function_name, "bsearch") == 0 && 2753 rn->u.call->args_len >= 2 && 2754 is_const_pointer(rn->u.call->args[1])) { 2755 /* call to '%s' effectively discards 'const' from argument */ 2756 warning(346, function_name); 2757 } 2758 } 2759 2760 static bool 2761 check_assign_void_pointer_compat(op_t op, int arg, 2762 const type_t *ltp, tspec_t lt, 2763 const type_t *lstp, tspec_t lst, 2764 const tnode_t *rn, 2765 const type_t *rtp, tspec_t rt, 2766 const type_t *rstp, tspec_t rst) 2767 { 2768 if (!(lt == PTR && rt == PTR && (lst == VOID || rst == VOID || 2769 types_compatible(lstp, rstp, 2770 true, false, NULL)))) 2771 return false; 2772 2773 /* compatible pointer types (qualifiers ignored) */ 2774 if (allow_c90 && 2775 ((!lstp->t_const && rstp->t_const) || 2776 (!lstp->t_volatile && rstp->t_volatile))) { 2777 /* left side has not all qualifiers of right */ 2778 switch (op) { 2779 case INIT: 2780 case RETURN: 2781 /* incompatible pointer types to '%s' and '%s' */ 2782 warning(182, type_name(lstp), type_name(rstp)); 2783 break; 2784 case FARG: 2785 /* converting '%s' to incompatible '%s' ... */ 2786 warning(153, 2787 type_name(rtp), type_name(ltp), arg); 2788 break; 2789 default: 2790 /* operands of '%s' have incompatible pointer ... */ 2791 warning(128, op_name(op), 2792 type_name(lstp), type_name(rstp)); 2793 break; 2794 } 2795 } 2796 2797 if (allow_c90) 2798 check_unconst_function(lstp, rn); 2799 2800 return true; 2801 } 2802 2803 static bool 2804 check_assign_pointer_integer(op_t op, int arg, 2805 const type_t *ltp, tspec_t lt, 2806 const type_t *rtp, tspec_t rt) 2807 { 2808 2809 if (!((lt == PTR && is_integer(rt)) || (is_integer(lt) && rt == PTR))) 2810 return false; 2811 2812 const char *lx = lt == PTR ? "pointer" : "integer"; 2813 const char *rx = rt == PTR ? "pointer" : "integer"; 2814 2815 switch (op) { 2816 case INIT: 2817 case RETURN: 2818 /* illegal combination of %s '%s' and %s '%s' */ 2819 warning(183, lx, type_name(ltp), rx, type_name(rtp)); 2820 break; 2821 case FARG: 2822 /* illegal combination of %s '%s' and %s '%s', arg #%d */ 2823 warning(154, 2824 lx, type_name(ltp), rx, type_name(rtp), arg); 2825 break; 2826 default: 2827 /* illegal combination of %s '%s' and %s '%s', op '%s' */ 2828 warning(123, 2829 lx, type_name(ltp), rx, type_name(rtp), op_name(op)); 2830 break; 2831 } 2832 return true; 2833 } 2834 2835 static bool 2836 check_assign_pointer(op_t op, int arg, 2837 const type_t *ltp, tspec_t lt, 2838 const type_t *rtp, tspec_t rt) 2839 { 2840 if (!(lt == PTR && rt == PTR)) 2841 return false; 2842 2843 if (op == FARG) 2844 /* converting '%s' to incompatible '%s' for ... */ 2845 warning(153, type_name(rtp), type_name(ltp), arg); 2846 else 2847 warn_incompatible_pointers(op, ltp, rtp); 2848 return true; 2849 } 2850 2851 static void 2852 warn_assign(op_t op, int arg, 2853 const type_t *ltp, tspec_t lt, 2854 const type_t *rtp, tspec_t rt) 2855 { 2856 switch (op) { 2857 case INIT: 2858 /* cannot initialize '%s' from '%s' */ 2859 error(185, type_name(ltp), type_name(rtp)); 2860 break; 2861 case RETURN: 2862 /* function has return type '%s' but returns '%s' */ 2863 error(211, type_name(ltp), type_name(rtp)); 2864 break; 2865 case FARG: 2866 /* passing '%s' to incompatible '%s', arg #%d */ 2867 warning(155, type_name(rtp), type_name(ltp), arg); 2868 break; 2869 default: 2870 warn_incompatible_types(op, ltp, lt, rtp, rt); 2871 break; 2872 } 2873 } 2874 2875 /* 2876 * Checks type compatibility for ASSIGN, INIT, FARG and RETURN 2877 * and prints warnings/errors if necessary. 2878 * Returns whether the types are (almost) compatible. 2879 */ 2880 static bool 2881 check_assign_types_compatible(op_t op, int arg, 2882 const tnode_t *ln, const tnode_t *rn) 2883 { 2884 tspec_t lt, rt, lst = NO_TSPEC, rst = NO_TSPEC; 2885 type_t *ltp, *rtp, *lstp = NULL, *rstp = NULL; 2886 2887 if ((lt = (ltp = ln->tn_type)->t_tspec) == PTR) 2888 lst = (lstp = ltp->t_subt)->t_tspec; 2889 if ((rt = (rtp = rn->tn_type)->t_tspec) == PTR) 2890 rst = (rstp = rtp->t_subt)->t_tspec; 2891 2892 if (lt == BOOL && is_scalar(rt)) /* C99 6.3.1.2 */ 2893 return true; 2894 2895 if (is_arithmetic(lt) && (is_arithmetic(rt) || rt == BOOL)) 2896 return true; 2897 2898 if (is_struct_or_union(lt) && is_struct_or_union(rt)) 2899 return ltp->u.sou == rtp->u.sou; 2900 2901 if (lt == PTR && is_null_pointer(rn)) { 2902 if (is_integer(rn->tn_type->t_tspec)) 2903 /* implicit conversion from integer 0 to pointer ... */ 2904 query_message(15, type_name(ltp)); 2905 return true; 2906 } 2907 2908 check_assign_void_pointer(op, arg, lt, lst, rt, rst); 2909 2910 if (check_assign_void_pointer_compat(op, arg, 2911 ltp, lt, lstp, lst, rn, rtp, rt, rstp, rst)) 2912 return true; 2913 2914 if (check_assign_pointer_integer(op, arg, ltp, lt, rtp, rt)) 2915 return true; 2916 2917 if (check_assign_pointer(op, arg, ltp, lt, rtp, rt)) 2918 return true; 2919 2920 warn_assign(op, arg, ltp, lt, rtp, rt); 2921 return false; 2922 } 2923 2924 static bool 2925 has_side_effect(const tnode_t *tn) /* NOLINT(misc-no-recursion) */ 2926 { 2927 op_t op = tn->tn_op; 2928 2929 if (modtab[op].m_has_side_effect) 2930 return true; 2931 2932 if (op == CVT && tn->tn_type->t_tspec == VOID) 2933 return has_side_effect(tn->u.ops.left); 2934 2935 /* XXX: Why not has_side_effect(tn->u.ops.left) as well? */ 2936 if (op == LOGAND || op == LOGOR) 2937 return has_side_effect(tn->u.ops.right); 2938 2939 /* XXX: Why not has_side_effect(tn->u.ops.left) as well? */ 2940 if (op == QUEST) 2941 return has_side_effect(tn->u.ops.right); 2942 2943 if (op == COLON || op == COMMA) { 2944 return has_side_effect(tn->u.ops.left) || 2945 has_side_effect(tn->u.ops.right); 2946 } 2947 2948 return false; 2949 } 2950 2951 static bool 2952 is_void_cast(const tnode_t *tn) 2953 { 2954 2955 return tn->tn_op == CVT && tn->tn_cast && 2956 tn->tn_type->t_tspec == VOID; 2957 } 2958 2959 static bool 2960 is_local_symbol(const tnode_t *tn) 2961 { 2962 2963 return tn->tn_op == LOAD && 2964 tn->u.ops.left->tn_op == NAME && 2965 tn->u.ops.left->u.sym->s_scl == AUTO; 2966 } 2967 2968 static bool 2969 is_int_constant_zero(const tnode_t *tn) 2970 { 2971 2972 return tn->tn_op == CON && 2973 tn->tn_type->t_tspec == INT && 2974 tn->u.value.u.integer == 0; 2975 } 2976 2977 static void 2978 check_null_effect(const tnode_t *tn) 2979 { 2980 2981 if (hflag && 2982 !has_side_effect(tn) && 2983 !(is_void_cast(tn) && is_local_symbol(tn->u.ops.left)) && 2984 !(is_void_cast(tn) && is_int_constant_zero(tn->u.ops.left))) { 2985 /* expression has null effect */ 2986 warning(129); 2987 } 2988 } 2989 2990 /* 2991 * Check the types for specific operators and type combinations. 2992 * 2993 * At this point, the operands already conform to the type requirements of 2994 * the operator, such as being integer, floating or scalar. 2995 */ 2996 static bool 2997 typeok_op(op_t op, int arg, 2998 const tnode_t *ln, const type_t *ltp, tspec_t lt, 2999 const tnode_t *rn, const type_t *rtp, tspec_t rt) 3000 { 3001 switch (op) { 3002 case ARROW: 3003 return typeok_arrow(lt); 3004 case POINT: 3005 return typeok_point(ln, ltp, lt); 3006 case INCBEF: 3007 case DECBEF: 3008 case INCAFT: 3009 case DECAFT: 3010 return typeok_incdec(op, ln, ltp); 3011 case INDIR: 3012 return typeok_indir(ltp, lt); 3013 case ADDR: 3014 return typeok_address(op, ln, ltp, lt); 3015 case PLUS: 3016 return typeok_plus(op, ltp, lt, rtp, rt); 3017 case MINUS: 3018 return typeok_minus(op, ltp, lt, rtp, rt); 3019 case SHL: 3020 typeok_shl(op, lt, rt); 3021 goto shift; 3022 case SHR: 3023 typeok_shr(op, ln, lt, rn, rt); 3024 shift: 3025 typeok_shift(ltp, lt, rn, rt); 3026 break; 3027 case LT: 3028 case LE: 3029 case GT: 3030 case GE: 3031 compare: 3032 return typeok_compare(op, ln, ltp, lt, rn, rtp, rt); 3033 case EQ: 3034 case NE: 3035 if (is_typeok_eq(ln, lt, rn, rt)) 3036 break; 3037 goto compare; 3038 case QUEST: 3039 return typeok_quest(lt, rn); 3040 case COLON: 3041 return typeok_colon(ln, ltp, lt, rn, rtp, rt); 3042 case ASSIGN: 3043 case INIT: 3044 case FARG: 3045 case RETURN: 3046 if (!check_assign_types_compatible(op, arg, ln, rn)) 3047 return false; 3048 goto assign; 3049 case MULASS: 3050 case DIVASS: 3051 case MODASS: 3052 goto assign; 3053 case ADDASS: 3054 case SUBASS: 3055 if ((lt == PTR && !is_integer(rt)) || rt == PTR) { 3056 warn_incompatible_types(op, ltp, lt, rtp, rt); 3057 return false; 3058 } 3059 goto assign; 3060 case SHLASS: 3061 goto assign; 3062 case SHRASS: 3063 if (pflag && !is_uinteger(lt) && 3064 !(!allow_c90 && is_uinteger(rt))) { 3065 /* bitwise '%s' on signed value possibly nonportable */ 3066 warning(117, op_name(op)); 3067 } 3068 goto assign; 3069 case ANDASS: 3070 case XORASS: 3071 case ORASS: 3072 assign: 3073 return typeok_assign(op, ln, ltp, lt); 3074 case COMMA: 3075 if (!modtab[ln->tn_op].m_has_side_effect) 3076 check_null_effect(ln); 3077 break; 3078 default: 3079 break; 3080 } 3081 return true; 3082 } 3083 3084 static void 3085 check_bad_enum_operation(op_t op, const tnode_t *ln, const tnode_t *rn) 3086 { 3087 3088 if (!eflag) 3089 return; 3090 3091 /* Allow enum in array indices. */ 3092 if (op == PLUS && 3093 ((ln->tn_type->t_is_enum && rn->tn_type->t_tspec == PTR) || 3094 (rn->tn_type->t_is_enum && ln->tn_type->t_tspec == PTR))) { 3095 return; 3096 } 3097 3098 /* dubious operation '%s' on enum */ 3099 warning(241, op_name(op)); 3100 } 3101 3102 static void 3103 check_enum_type_mismatch(op_t op, int arg, const tnode_t *ln, const tnode_t *rn) 3104 { 3105 const mod_t *mp = &modtab[op]; 3106 3107 if (ln->tn_type->u.enumer != rn->tn_type->u.enumer) { 3108 switch (op) { 3109 case INIT: 3110 /* enum type mismatch between '%s' and '%s' in ... */ 3111 warning(210, 3112 type_name(ln->tn_type), type_name(rn->tn_type)); 3113 break; 3114 case FARG: 3115 /* function expects '%s', passing '%s' for arg #%d */ 3116 warning(156, 3117 type_name(ln->tn_type), type_name(rn->tn_type), 3118 arg); 3119 break; 3120 case RETURN: 3121 /* function has return type '%s' but returns '%s' */ 3122 warning(211, 3123 type_name(ln->tn_type), type_name(rn->tn_type)); 3124 break; 3125 default: 3126 /* enum type mismatch: '%s' '%s' '%s' */ 3127 warning(130, type_name(ln->tn_type), op_name(op), 3128 type_name(rn->tn_type)); 3129 break; 3130 } 3131 } else if (Pflag && eflag && mp->m_comparison && op != EQ && op != NE) 3132 /* operator '%s' assumes that '%s' is ordered */ 3133 warning(243, op_name(op), type_name(ln->tn_type)); 3134 } 3135 3136 static void 3137 check_enum_int_mismatch(op_t op, int arg, const tnode_t *ln, const tnode_t *rn) 3138 { 3139 3140 if (!eflag) 3141 return; 3142 3143 switch (op) { 3144 case INIT: 3145 /* 3146 * Initialization with 0 is allowed. Otherwise, all implicit 3147 * initializations would need to be warned upon as well. 3148 */ 3149 if (!rn->tn_type->t_is_enum && rn->tn_op == CON && 3150 is_integer(rn->tn_type->t_tspec) && 3151 rn->u.value.u.integer == 0) { 3152 return; 3153 } 3154 /* initialization of '%s' with '%s' */ 3155 warning(277, type_name(ln->tn_type), type_name(rn->tn_type)); 3156 break; 3157 case FARG: 3158 /* combination of '%s' and '%s', arg #%d */ 3159 warning(278, 3160 type_name(ln->tn_type), type_name(rn->tn_type), arg); 3161 break; 3162 case RETURN: 3163 /* combination of '%s' and '%s' in return */ 3164 warning(279, type_name(ln->tn_type), type_name(rn->tn_type)); 3165 break; 3166 default: 3167 /* combination of '%s' and '%s', op '%s' */ 3168 warning(242, type_name(ln->tn_type), type_name(rn->tn_type), 3169 op_name(op)); 3170 break; 3171 } 3172 } 3173 3174 static void 3175 typeok_enum(op_t op, const mod_t *mp, int arg, 3176 const tnode_t *ln, const type_t *ltp, 3177 const tnode_t *rn, const type_t *rtp) 3178 { 3179 if (mp->m_bad_on_enum && 3180 (ltp->t_is_enum || (mp->m_binary && rtp->t_is_enum))) { 3181 check_bad_enum_operation(op, ln, rn); 3182 } else if (mp->m_valid_on_enum && 3183 (ltp->t_is_enum && rtp != NULL && rtp->t_is_enum)) { 3184 check_enum_type_mismatch(op, arg, ln, rn); 3185 } else if (mp->m_valid_on_enum && 3186 (ltp->t_is_enum || (rtp != NULL && rtp->t_is_enum))) { 3187 check_enum_int_mismatch(op, arg, ln, rn); 3188 } 3189 } 3190 3191 /* Perform most type checks. Return whether the types are ok. */ 3192 bool 3193 typeok(op_t op, int arg, const tnode_t *ln, const tnode_t *rn) 3194 { 3195 3196 const mod_t *mp = &modtab[op]; 3197 3198 type_t *ltp = ln->tn_type; 3199 tspec_t lt = ltp->t_tspec; 3200 3201 type_t *rtp = mp->m_binary ? rn->tn_type : NULL; 3202 tspec_t rt = mp->m_binary ? rtp->t_tspec : NO_TSPEC; 3203 3204 if (Tflag && !typeok_scalar_strict_bool(op, mp, arg, ln, rn)) 3205 return false; 3206 if (!typeok_scalar(op, mp, ltp, lt, rtp, rt)) 3207 return false; 3208 3209 if (!typeok_op(op, arg, ln, ltp, lt, rn, rtp, rt)) 3210 return false; 3211 3212 typeok_enum(op, mp, arg, ln, ltp, rn, rtp); 3213 return true; 3214 } 3215 3216 /* In traditional C, keep unsigned and promote FLOAT to DOUBLE. */ 3217 static tspec_t 3218 promote_trad(tspec_t t) 3219 { 3220 3221 if (t == UCHAR || t == USHORT) 3222 return UINT; 3223 if (t == CHAR || t == SCHAR || t == SHORT) 3224 return INT; 3225 if (t == FLOAT) 3226 return DOUBLE; 3227 if (t == ENUM) 3228 return INT; 3229 return t; 3230 } 3231 3232 /* 3233 * C99 6.3.1.1p2 requires for types with lower rank than int that "If an int 3234 * can represent all the values of the original type, the value is converted 3235 * to an int; otherwise it is converted to an unsigned int", and that "All 3236 * other types are unchanged by the integer promotions". 3237 */ 3238 static tspec_t 3239 promote_c90(const tnode_t *tn, tspec_t t, bool farg) 3240 { 3241 if (tn->tn_type->t_bitfield) { 3242 unsigned int width = tn->tn_type->t_bit_field_width; 3243 unsigned int int_width = size_in_bits(INT); 3244 // XXX: What about _Bool bit-fields, since C99? 3245 if (width < int_width) 3246 return INT; 3247 if (width == int_width) 3248 return is_uinteger(t) ? UINT : INT; 3249 return t; 3250 } 3251 3252 if (t == CHAR || t == SCHAR) 3253 return INT; 3254 if (t == UCHAR) 3255 return size_in_bits(CHAR) < size_in_bits(INT) ? INT : UINT; 3256 if (t == SHORT) 3257 return INT; 3258 if (t == USHORT) 3259 return size_in_bits(SHORT) < size_in_bits(INT) ? INT : UINT; 3260 if (t == ENUM) 3261 return INT; 3262 if (farg && t == FLOAT) 3263 return DOUBLE; 3264 return t; 3265 } 3266 3267 /* 3268 * Performs the "integer promotions" (C99 6.3.1.1p2), which convert small 3269 * integer types to either int or unsigned int. 3270 * 3271 * If allow_c90 is unset or the operand is a function argument with no type 3272 * information (no prototype or variable # of args), converts float to double. 3273 */ 3274 tnode_t * 3275 promote(op_t op, bool farg, tnode_t *tn) 3276 { 3277 3278 const type_t *otp = tn->tn_type; 3279 tspec_t ot = otp->t_tspec; 3280 if (!is_arithmetic(ot)) 3281 return tn; 3282 3283 tspec_t nt = allow_c90 ? promote_c90(tn, ot, farg) : promote_trad(ot); 3284 if (nt == ot) 3285 return tn; 3286 3287 type_t *ntp = expr_dup_type(gettyp(nt)); 3288 ntp->t_tspec = nt; 3289 ntp->t_is_enum = otp->t_is_enum; 3290 if (ntp->t_is_enum) 3291 ntp->u.enumer = otp->u.enumer; 3292 ntp->t_bitfield = otp->t_bitfield; 3293 if (ntp->t_bitfield) { 3294 ntp->t_bit_field_width = otp->t_bit_field_width; 3295 ntp->t_bit_field_offset = otp->t_bit_field_offset; 3296 } 3297 if (ntp->t_bitfield && is_uinteger(ot) && !is_uinteger(nt)) 3298 ntp->t_bit_field_width++; 3299 return convert(op, 0, ntp, tn); 3300 } 3301 3302 static void 3303 check_lossy_floating_to_integer_conversion( 3304 op_t op, int arg, const type_t *tp, const tnode_t *tn) 3305 { 3306 long double x = tn->u.value.u.floating; 3307 integer_constraints ic = ic_any(tp); 3308 if (is_uinteger(tp->t_tspec) 3309 ? x >= ic.umin && x <= ic.umax && x == (uint64_t)x 3310 : x >= ic.smin && x <= ic.smax && x == (int64_t)x) 3311 return; 3312 if (op == FARG) 3313 /* lossy conversion of %Lg to '%s', arg #%d */ 3314 warning(380, x, type_name(tp), arg); 3315 else 3316 /* lossy conversion of %Lg to '%s' */ 3317 warning(381, x, type_name(tp)); 3318 } 3319 3320 static void 3321 convert_integer_from_floating( 3322 op_t op, int arg, const type_t *tp, const tnode_t *tn) 3323 { 3324 3325 if (op == CVT) 3326 /* cast from floating point '%s' to integer '%s' */ 3327 query_message(2, type_name(tn->tn_type), type_name(tp)); 3328 else 3329 /* implicit conversion from floating point '%s' to ... */ 3330 query_message(1, type_name(tn->tn_type), type_name(tp)); 3331 if (tn->tn_op == CON) 3332 check_lossy_floating_to_integer_conversion(op, arg, tp, tn); 3333 } 3334 3335 static bool 3336 should_warn_about_prototype_conversion(tspec_t nt, 3337 tspec_t ot, const tnode_t *ptn) 3338 { 3339 3340 if (nt == ot) 3341 return false; 3342 3343 if (nt == ENUM && ot == INT) 3344 return false; 3345 3346 if (is_floating(nt) != is_floating(ot) || 3347 portable_rank_cmp(nt, ot) != 0) { 3348 /* representation and/or width change */ 3349 if (!is_integer(ot)) 3350 return true; 3351 /* 3352 * XXX: Investigate whether this rule makes sense; see 3353 * tests/usr.bin/xlint/lint1/platform_long.c. 3354 */ 3355 return portable_rank_cmp(ot, INT) > 0; 3356 } 3357 3358 if (!hflag) 3359 return false; 3360 3361 /* 3362 * If the types differ only in sign and the argument has the same 3363 * representation in both types, print no warning. 3364 */ 3365 if (ptn->tn_op == CON && is_integer(nt) && 3366 signed_type(nt) == signed_type(ot) && 3367 !msb(ptn->u.value.u.integer, ot)) 3368 return false; 3369 3370 return true; 3371 } 3372 3373 /* 3374 * Warn if a prototype causes a type conversion that is different from what 3375 * would happen to the same argument in the absence of a prototype. This 3376 * check is intended for code that needs to stay compatible with pre-C90 C. 3377 * 3378 * Errors/warnings about illegal type combinations are already printed 3379 * in check_assign_types_compatible(). 3380 */ 3381 static void 3382 check_prototype_conversion(int arg, tspec_t nt, tspec_t ot, type_t *tp, 3383 tnode_t *tn) 3384 { 3385 3386 if (!is_arithmetic(nt) || !is_arithmetic(ot)) 3387 return; 3388 3389 /* 3390 * If the type of the formal parameter is char/short, a warning would 3391 * be useless, because functions declared the old style can't expect 3392 * char/short arguments. 3393 */ 3394 if (nt == CHAR || nt == SCHAR || nt == UCHAR || 3395 nt == SHORT || nt == USHORT) 3396 return; 3397 3398 tnode_t *ptn = promote(NOOP, true, tn); 3399 ot = ptn->tn_type->t_tspec; 3400 3401 if (should_warn_about_prototype_conversion(nt, ot, ptn)) { 3402 /* argument %d is converted from '%s' to '%s' ... */ 3403 warning(259, arg, type_name(tn->tn_type), type_name(tp)); 3404 } 3405 } 3406 3407 /* 3408 * When converting a large integer type to a small integer type, in some 3409 * cases the value of the actual expression is further restricted than the 3410 * type bounds, such as in (expr & 0xFF) or (expr % 100) or (expr >> 24). 3411 */ 3412 static bool 3413 can_represent(const type_t *tp, const tnode_t *tn) 3414 { 3415 3416 debug_step("%s: type '%s'", __func__, type_name(tp)); 3417 debug_node(tn); 3418 3419 uint64_t nmask = value_bits(width_in_bits(tp)); 3420 if (!is_uinteger(tp->t_tspec)) 3421 nmask >>= 1; 3422 3423 integer_constraints c = ic_expr(tn); 3424 if ((~c.bclr & ~nmask) == 0) 3425 return true; 3426 3427 integer_constraints tpc = ic_any(tp); 3428 if (is_uinteger(tp->t_tspec) 3429 ? tpc.umin <= c.umin && tpc.umax >= c.umax 3430 : tpc.smin <= c.smin && tpc.smax >= c.smax) 3431 return true; 3432 3433 return false; 3434 } 3435 3436 static bool 3437 should_warn_about_integer_conversion(const type_t *ntp, tspec_t nt, 3438 const tnode_t *otn, tspec_t ot) 3439 { 3440 3441 // XXX: The portable_rank_cmp aims at portable mode, independent of the 3442 // current platform, while can_represent acts on the actual type sizes 3443 // from the current platform. This mix is inconsistent, but anything 3444 // else would make the exact conditions too complicated to grasp. 3445 if (aflag > 0 && portable_rank_cmp(nt, ot) < 0) { 3446 if (ot == LONG || ot == ULONG 3447 || ot == LLONG || ot == ULLONG 3448 #ifdef INT128_SIZE 3449 || ot == INT128 || ot == UINT128 3450 #endif 3451 || aflag > 1) 3452 return !can_represent(ntp, otn); 3453 } 3454 return false; 3455 } 3456 3457 static void 3458 convert_integer_from_integer(op_t op, int arg, tspec_t nt, tspec_t ot, 3459 type_t *tp, tnode_t *tn) 3460 { 3461 3462 if (tn->tn_op == CON) 3463 return; 3464 3465 if (op == CVT) 3466 return; 3467 3468 if (Pflag && pflag && aflag > 0 && 3469 portable_rank_cmp(nt, ot) > 0 && 3470 is_uinteger(nt) != is_uinteger(ot)) { 3471 if (op == FARG) 3472 /* conversion to '%s' may sign-extend ... */ 3473 warning(297, type_name(tp), arg); 3474 else 3475 /* conversion to '%s' may sign-extend ... */ 3476 warning(131, type_name(tp)); 3477 } 3478 3479 if (Pflag && portable_rank_cmp(nt, ot) > 0 && 3480 (tn->tn_op == PLUS || tn->tn_op == MINUS || tn->tn_op == MULT || 3481 tn->tn_op == SHL)) { 3482 /* suggest cast from '%s' to '%s' on op '%s' to ... */ 3483 warning(324, type_name(gettyp(ot)), type_name(tp), 3484 op_name(tn->tn_op)); 3485 } 3486 3487 if (should_warn_about_integer_conversion(tp, nt, tn, ot)) { 3488 if (op == FARG) { 3489 /* conversion from '%s' to '%s' may lose ... */ 3490 warning(298, 3491 type_name(tn->tn_type), type_name(tp), arg); 3492 } else { 3493 /* conversion from '%s' to '%s' may lose accuracy */ 3494 warning(132, 3495 type_name(tn->tn_type), type_name(tp)); 3496 } 3497 } 3498 3499 if (any_query_enabled && is_uinteger(nt) != is_uinteger(ot)) 3500 /* implicit conversion changes sign from '%s' to '%s' */ 3501 query_message(3, type_name(tn->tn_type), type_name(tp)); 3502 } 3503 3504 static void 3505 convert_integer_from_pointer(op_t op, tspec_t nt, type_t *tp, tnode_t *tn) 3506 { 3507 3508 if (tn->tn_op == CON) 3509 return; 3510 if (op != CVT) 3511 return; /* We already got an error. */ 3512 if (portable_rank_cmp(nt, PTR) >= 0) 3513 return; 3514 3515 if (pflag && size_in_bits(nt) >= size_in_bits(PTR)) { 3516 /* conversion of pointer to '%s' may lose bits */ 3517 warning(134, type_name(tp)); 3518 } else { 3519 /* conversion of pointer to '%s' loses bits */ 3520 warning(133, type_name(tp)); 3521 } 3522 } 3523 3524 static bool 3525 struct_starts_with(const type_t *struct_tp, const type_t *member_tp) 3526 { 3527 3528 return struct_tp->u.sou->sou_first_member != NULL && 3529 types_compatible(struct_tp->u.sou->sou_first_member->s_type, 3530 member_tp, true, false, NULL); 3531 } 3532 3533 static bool 3534 is_byte_array(const type_t *tp) 3535 { 3536 3537 return tp->t_tspec == ARRAY && 3538 (tp->t_subt->t_tspec == CHAR || tp->t_subt->t_tspec == UCHAR); 3539 } 3540 3541 static bool 3542 union_contains(const type_t *utp, const type_t *mtp) 3543 { 3544 for (const sym_t *mem = utp->u.sou->sou_first_member; 3545 mem != NULL; mem = mem->s_next) { 3546 if (types_compatible(mem->s_type, mtp, true, false, NULL)) 3547 return true; 3548 } 3549 return false; 3550 } 3551 3552 static bool 3553 should_warn_about_pointer_cast(const type_t *nstp, tspec_t nst, 3554 const type_t *ostp, tspec_t ost) 3555 { 3556 3557 while (nst == ARRAY) 3558 nstp = nstp->t_subt, nst = nstp->t_tspec; 3559 while (ost == ARRAY) 3560 ostp = ostp->t_subt, ost = ostp->t_tspec; 3561 3562 if (nst == STRUCT && ost == STRUCT && 3563 (struct_starts_with(nstp, ostp) || 3564 struct_starts_with(ostp, nstp))) 3565 return false; 3566 3567 if (is_incomplete(nstp) || is_incomplete(ostp)) 3568 return false; 3569 3570 if (nst == CHAR || nst == UCHAR) 3571 return false; /* for the sake of traditional C code */ 3572 if (ost == CHAR || ost == UCHAR) 3573 return false; /* for the sake of traditional C code */ 3574 3575 /* Allow cast between pointers to sockaddr variants. */ 3576 if (nst == STRUCT && ost == STRUCT) { 3577 const sym_t *nmem = nstp->u.sou->sou_first_member; 3578 const sym_t *omem = ostp->u.sou->sou_first_member; 3579 while (nmem != NULL && omem != NULL && 3580 types_compatible(nmem->s_type, omem->s_type, 3581 true, false, NULL)) 3582 nmem = nmem->s_next, omem = omem->s_next; 3583 if (nmem != NULL && is_byte_array(nmem->s_type)) 3584 return false; 3585 if (omem != NULL && is_byte_array(omem->s_type)) 3586 return false; 3587 if (nmem == NULL && omem == NULL) 3588 return false; 3589 } 3590 3591 if (nst == UNION || ost == UNION) { 3592 const type_t *union_tp = nst == UNION ? nstp : ostp; 3593 const type_t *other_tp = nst == UNION ? ostp : nstp; 3594 if (union_contains(union_tp, other_tp)) 3595 return false; 3596 } 3597 3598 if (is_struct_or_union(nst) && is_struct_or_union(ost)) 3599 return nstp->u.sou != ostp->u.sou; 3600 3601 enum rank_kind rk1 = type_properties(nst)->tt_rank_kind; 3602 enum rank_kind rk2 = type_properties(ost)->tt_rank_kind; 3603 if (rk1 != rk2 || rk1 == RK_NONE) 3604 return true; 3605 3606 return portable_rank_cmp(nst, ost) != 0; 3607 } 3608 3609 static void 3610 convert_pointer_from_pointer(type_t *ntp, tnode_t *tn) 3611 { 3612 const type_t *nstp = ntp->t_subt; 3613 const type_t *otp = tn->tn_type; 3614 const type_t *ostp = otp->t_subt; 3615 tspec_t nst = nstp->t_tspec; 3616 tspec_t ost = ostp->t_tspec; 3617 3618 if (nst == VOID || ost == VOID) { 3619 /* TODO: C99 behaves like C90 here. */ 3620 if (!allow_trad && !allow_c99 && (nst == FUNC || ost == FUNC)) { 3621 const char *nts, *ots; 3622 /* null pointers are already handled in convert() */ 3623 *(nst == FUNC ? &nts : &ots) = "function pointer"; 3624 *(nst == VOID ? &nts : &ots) = "'void *'"; 3625 /* conversion of %s to %s requires a cast */ 3626 warning(303, ots, nts); 3627 } 3628 return; 3629 } 3630 if (nst == FUNC && ost == FUNC) 3631 return; 3632 if (nst == FUNC || ost == FUNC) { 3633 /* converting '%s' to '%s' is questionable */ 3634 warning(229, type_name(otp), type_name(ntp)); 3635 return; 3636 } 3637 3638 if (hflag && alignment(nstp) > alignment(ostp) && 3639 ost != CHAR && ost != UCHAR && 3640 !is_incomplete(ostp) && 3641 !(nst == UNION && union_contains(nstp, ostp))) { 3642 /* converting '%s' to '%s' increases alignment ... */ 3643 warning(135, type_name(otp), type_name(ntp), 3644 alignment(ostp), alignment(nstp)); 3645 } 3646 3647 if (cflag && should_warn_about_pointer_cast(nstp, nst, ostp, ost)) { 3648 /* pointer cast from '%s' to '%s' may be troublesome */ 3649 warning(247, type_name(otp), type_name(ntp)); 3650 } 3651 } 3652 3653 /* 3654 * Insert a conversion operator, which converts the type of the node 3655 * to another given type. 3656 * 3657 * Possible values for 'op': 3658 * CVT a cast-expression 3659 * binary integer promotion for one of the operands, or a usual 3660 * arithmetic conversion 3661 * binary plain or compound assignments to bit-fields 3662 * FARG 'arg' is the number of the parameter (used for warnings) 3663 * NOOP several other implicit conversions 3664 * ... 3665 */ 3666 tnode_t * 3667 convert(op_t op, int arg, type_t *tp, tnode_t *tn) 3668 { 3669 tspec_t nt = tp->t_tspec; 3670 tspec_t ot = tn->tn_type->t_tspec; 3671 3672 if (allow_trad && allow_c90 && op == FARG) 3673 check_prototype_conversion(arg, nt, ot, tp, tn); 3674 3675 if (nt == BOOL) { 3676 /* No further checks. */ 3677 3678 } else if (is_integer(nt)) { 3679 if (ot == BOOL) { 3680 /* No further checks. */ 3681 } else if (is_integer(ot)) 3682 convert_integer_from_integer(op, arg, nt, ot, tp, tn); 3683 else if (is_floating(ot)) 3684 convert_integer_from_floating(op, arg, tp, tn); 3685 else if (ot == PTR) 3686 convert_integer_from_pointer(op, nt, tp, tn); 3687 3688 } else if (is_floating(nt)) { 3689 if (is_integer(ot) && op != CVT) { 3690 /* implicit conversion from integer '%s' to ... */ 3691 query_message(19, 3692 type_name(tn->tn_type), type_name(tp)); 3693 } 3694 3695 } else if (nt == PTR) { 3696 if (is_null_pointer(tn)) { 3697 /* a null pointer may be assigned to any pointer. */ 3698 } else if (ot == PTR && op == CVT) 3699 convert_pointer_from_pointer(tp, tn); 3700 } 3701 3702 tnode_t *ntn = expr_alloc_tnode(); 3703 ntn->tn_op = CVT; 3704 ntn->tn_type = tp; 3705 ntn->tn_cast = op == CVT; 3706 ntn->tn_sys |= tn->tn_sys; 3707 ntn->u.ops.right = NULL; 3708 if (tn->tn_op != CON || nt == VOID) { 3709 ntn->u.ops.left = tn; 3710 } else { 3711 ntn->tn_op = CON; 3712 convert_constant(op, arg, ntn->tn_type, &ntn->u.value, 3713 &tn->u.value); 3714 } 3715 3716 return ntn; 3717 } 3718 3719 static void 3720 convert_constant_from_floating(op_t op, int arg, const type_t *ntp, 3721 tspec_t nt, val_t *nv, val_t *ov) 3722 { 3723 long double max = 0.0, min = 0.0; 3724 3725 switch (nt) { 3726 case CHAR: 3727 max = TARG_CHAR_MAX; min = TARG_CHAR_MIN; break; 3728 case UCHAR: 3729 max = TARG_UCHAR_MAX; min = 0; break; 3730 case SCHAR: 3731 max = TARG_SCHAR_MAX; min = TARG_SCHAR_MIN; break; 3732 case SHORT: 3733 max = TARG_SHRT_MAX; min = TARG_SHRT_MIN; break; 3734 case USHORT: 3735 max = TARG_USHRT_MAX; min = 0; break; 3736 case ENUM: 3737 case INT: 3738 max = TARG_INT_MAX; min = TARG_INT_MIN; break; 3739 case UINT: 3740 max = TARG_UINT_MAX; min = 0; break; 3741 case LONG: 3742 max = TARG_LONG_MAX; min = TARG_LONG_MIN; break; 3743 case ULONG: 3744 max = TARG_ULONG_MAX; min = 0; break; 3745 case LLONG: 3746 max = LLONG_MAX; min = LLONG_MIN; break; 3747 case ULLONG: 3748 max = ULLONG_MAX; min = 0; break; 3749 case FLOAT: 3750 case FCOMPLEX: 3751 max = FLT_MAX; min = -FLT_MAX; break; 3752 case DOUBLE: 3753 case DCOMPLEX: 3754 max = DBL_MAX; min = -DBL_MAX; break; 3755 case LDOUBLE: 3756 case LCOMPLEX: 3757 /* LINTED 248; see floating_error_value. */ 3758 max = LDBL_MAX; min = -max; break; 3759 default: 3760 lint_assert(/*CONSTCOND*/false); 3761 } 3762 if (ov->u.floating > max || ov->u.floating < min) { 3763 lint_assert(nt != LDOUBLE); 3764 const char *ot_name = type_name(gettyp(ov->v_tspec)); 3765 const char *nt_name = type_name(ntp); 3766 if (is_integer(nt)) 3767 goto after_warning; 3768 if (op == FARG) 3769 /* conversion of '%s' to '%s' is out of range, ... */ 3770 warning(295, ot_name, nt_name, arg); 3771 else 3772 /* conversion of '%s' to '%s' is out of range */ 3773 warning(119, ot_name, nt_name); 3774 after_warning: 3775 ov->u.floating = ov->u.floating > 0 ? max : min; 3776 } 3777 3778 if (nt == FLOAT || nt == FCOMPLEX) 3779 nv->u.floating = (float)ov->u.floating; 3780 else if (nt == DOUBLE || nt == DCOMPLEX) 3781 nv->u.floating = (double)ov->u.floating; 3782 else if (nt == LDOUBLE || nt == LCOMPLEX) 3783 nv->u.floating = ov->u.floating; 3784 else 3785 nv->u.integer = (int64_t)ov->u.floating; 3786 } 3787 3788 static bool 3789 convert_constant_to_floating(tspec_t nt, val_t *nv, 3790 tspec_t ot, const val_t *v) 3791 { 3792 if (nt == FLOAT) { 3793 nv->u.floating = (ot == PTR || is_uinteger(ot)) ? 3794 (float)(uint64_t)v->u.integer : (float)v->u.integer; 3795 } else if (nt == DOUBLE) { 3796 nv->u.floating = (ot == PTR || is_uinteger(ot)) ? 3797 (double)(uint64_t)v->u.integer : (double)v->u.integer; 3798 } else if (nt == LDOUBLE) { 3799 nv->u.floating = (ot == PTR || is_uinteger(ot)) 3800 ? (long double)(uint64_t)v->u.integer 3801 : (long double)v->u.integer; 3802 } else 3803 return false; 3804 return true; 3805 } 3806 3807 /* 3808 * Print a warning if bits which were set are lost due to the conversion. 3809 * This can happen with operator ORASS only. 3810 */ 3811 static void 3812 convert_constant_check_range_bitor(size_t nsz, size_t osz, const val_t *v, 3813 uint64_t xmask, op_t op) 3814 { 3815 if (nsz < osz && (v->u.integer & xmask) != 0) 3816 /* constant truncated by conversion, op '%s' */ 3817 warning(306, op_name(op)); 3818 } 3819 3820 static void 3821 convert_constant_check_range_bitand(size_t nsz, size_t osz, 3822 uint64_t xmask, const val_t *nv, 3823 tspec_t ot, const val_t *v, 3824 const type_t *tp, op_t op) 3825 { 3826 if (nsz > osz && 3827 (nv->u.integer & bit((unsigned int)(osz - 1))) != 0 && 3828 (nv->u.integer & xmask) != xmask) { 3829 /* extra bits set to 0 in conversion of '%s' to '%s', ... */ 3830 warning(309, type_name(gettyp(ot)), 3831 type_name(tp), op_name(op)); 3832 } else if (nsz < osz && 3833 (v->u.integer & xmask) != xmask && 3834 (v->u.integer & xmask) != 0) 3835 /* constant truncated by conversion, op '%s' */ 3836 warning(306, op_name(op)); 3837 } 3838 3839 static void 3840 convert_constant_check_range_signed(op_t op, int arg, 3841 const type_t *ntp, int64_t ov) 3842 { 3843 if (op == ASSIGN) 3844 /* assignment of negative constant %lld to unsigned ... */ 3845 warning(164, (long long)ov, type_name(ntp)); 3846 else if (op == INIT) 3847 /* initialization of unsigned type '%s' with negative ... */ 3848 warning(221, type_name(ntp), (long long)ov); 3849 else if (op == FARG) 3850 /* conversion of negative constant %lld to unsigned ... */ 3851 warning(296, (long long)ov, type_name(ntp), arg); 3852 else if (modtab[op].m_comparison) { 3853 /* handled by check_integer_comparison() */ 3854 } else 3855 /* conversion of negative constant %lld to unsigned ... */ 3856 warning(222, (long long)ov, type_name(ntp)); 3857 } 3858 3859 /* 3860 * Loss of significant bit(s). All truncated bits of unsigned types or all 3861 * truncated bits plus the msb of the target for signed types are considered 3862 * to be significant bits. Loss of significant bits means that at least one 3863 * of the bits was set in an unsigned type or that at least one but not all 3864 * of the bits was set in a signed type. Loss of significant bits means that 3865 * it is not possible, also not with necessary casts, to convert back to the 3866 * original type. An example for a necessary cast is: 3867 * char c; int i; c = 128; 3868 * i = c; ** yields -128 ** 3869 * i = (unsigned char)c; ** yields 128 ** 3870 */ 3871 static void 3872 warn_constant_check_range_truncated(op_t op, int arg, const type_t *tp, 3873 tspec_t ot) 3874 { 3875 if (op == ASSIGN && tp->t_bitfield) 3876 /* precision lost in bit-field assignment */ 3877 warning(166); 3878 else if (op == ASSIGN) 3879 /* constant truncated by assignment */ 3880 warning(165); 3881 else if (op == INIT && tp->t_bitfield) 3882 /* bit-field initializer does not fit */ 3883 warning(180); 3884 else if (op == INIT) 3885 /* initializer does not fit */ 3886 warning(178); 3887 else if (op == CASE) 3888 /* case label affected by conversion */ 3889 warning(196); 3890 else if (op == FARG) 3891 /* conversion of '%s' to '%s' is out of range, arg #%d */ 3892 warning(295, type_name(gettyp(ot)), type_name(tp), arg); 3893 else 3894 /* conversion of '%s' to '%s' is out of range */ 3895 warning(119, type_name(gettyp(ot)), type_name(tp)); 3896 } 3897 3898 static void 3899 warn_constant_check_range_loss(op_t op, int arg, const type_t *tp, 3900 tspec_t ot) 3901 { 3902 if (op == ASSIGN && tp->t_bitfield) 3903 /* precision lost in bit-field assignment */ 3904 warning(166); 3905 else if (op == INIT && tp->t_bitfield) 3906 /* bit-field initializer out of range */ 3907 warning(11); 3908 else if (op == CASE) 3909 /* case label affected by conversion */ 3910 warning(196); 3911 else if (op == FARG) 3912 /* conversion of '%s' to '%s' is out of range, arg #%d */ 3913 warning(295, type_name(gettyp(ot)), type_name(tp), arg); 3914 else 3915 /* conversion of '%s' to '%s' is out of range */ 3916 warning(119, type_name(gettyp(ot)), type_name(tp)); 3917 } 3918 3919 static void 3920 convert_constant_check_range(tspec_t ot, const type_t *tp, tspec_t nt, 3921 op_t op, int arg, const val_t *v, val_t *nv) 3922 { 3923 unsigned int obitsz, nbitsz; 3924 uint64_t xmask, xmsk1; 3925 3926 obitsz = size_in_bits(ot); 3927 nbitsz = tp->t_bitfield ? tp->t_bit_field_width : size_in_bits(nt); 3928 xmask = value_bits(nbitsz) ^ value_bits(obitsz); 3929 xmsk1 = value_bits(nbitsz) ^ value_bits(obitsz - 1); 3930 if (op == ORASS || op == BITOR || op == BITXOR) { 3931 convert_constant_check_range_bitor( 3932 nbitsz, obitsz, v, xmask, op); 3933 } else if (op == ANDASS || op == BITAND) { 3934 convert_constant_check_range_bitand( 3935 nbitsz, obitsz, xmask, nv, ot, v, tp, op); 3936 } else if (nt != PTR && is_uinteger(nt) && 3937 ot != PTR && !is_uinteger(ot) && 3938 v->u.integer < 0) 3939 convert_constant_check_range_signed(op, arg, 3940 tp, v->u.integer); 3941 else if (nv->u.integer != v->u.integer && nbitsz <= obitsz && 3942 (v->u.integer & xmask) != 0 && 3943 (is_uinteger(ot) || (v->u.integer & xmsk1) != xmsk1)) 3944 warn_constant_check_range_truncated(op, arg, tp, ot); 3945 else if (nv->u.integer != v->u.integer) 3946 warn_constant_check_range_loss(op, arg, tp, ot); 3947 } 3948 3949 /* Converts a typed constant to a constant of another type. */ 3950 void 3951 convert_constant(op_t op, int arg, const type_t *ntp, val_t *nv, val_t *ov) 3952 { 3953 /* 3954 * TODO: make 'ov' const; the name of this function does not suggest 3955 * that it modifies 'ov'. 3956 */ 3957 tspec_t ot = ov->v_tspec; 3958 tspec_t nt = nv->v_tspec = ntp->t_tspec; 3959 bool range_check = false; 3960 3961 if (nt == BOOL) { /* C99 6.3.1.2 */ 3962 nv->v_unsigned_since_c90 = false; 3963 nv->u.integer = is_nonzero_val(ov) ? 1 : 0; 3964 return; 3965 } 3966 3967 if (ot == FLOAT || ot == DOUBLE || ot == LDOUBLE) 3968 convert_constant_from_floating(op, arg, ntp, nt, nv, ov); 3969 else if (!convert_constant_to_floating(nt, nv, ot, ov)) { 3970 range_check = true; /* Check for lost precision. */ 3971 nv->u.integer = ov->u.integer; 3972 } 3973 3974 if (allow_trad && allow_c90 && ov->v_unsigned_since_c90 && 3975 (is_floating(nt) || ( 3976 (is_integer(nt) && !is_uinteger(nt) && 3977 portable_rank_cmp(nt, ot) > 0)))) { 3978 /* C90 treats constant as unsigned */ 3979 warning(157); 3980 ov->v_unsigned_since_c90 = false; 3981 } 3982 3983 if (is_integer(nt)) { 3984 unsigned int size = ntp->t_bitfield 3985 ? ntp->t_bit_field_width : size_in_bits(nt); 3986 nv->u.integer = convert_integer(nv->u.integer, nt, size); 3987 } 3988 3989 if (range_check && op != CVT) 3990 convert_constant_check_range(ot, ntp, nt, op, arg, ov, nv); 3991 } 3992 3993 tnode_t * 3994 build_sizeof(const type_t *tp) 3995 { 3996 unsigned int size_in_bytes = type_size_in_bits(tp) / CHAR_SIZE; 3997 tnode_t *tn = build_integer_constant(SIZEOF_TSPEC, size_in_bytes); 3998 tn->tn_system_dependent = true; 3999 debug_step("build_sizeof '%s' = %u", type_name(tp), size_in_bytes); 4000 return tn; 4001 } 4002 4003 tnode_t * 4004 build_offsetof(const type_t *tp, designation dn) 4005 { 4006 unsigned int offset_in_bits = 0; 4007 4008 if (!is_struct_or_union(tp->t_tspec)) { 4009 /* unacceptable operand of '%s' */ 4010 error(111, "offsetof"); 4011 goto proceed; 4012 } 4013 for (size_t i = 0; i < dn.dn_len; i++) { 4014 const designator *dr = dn.dn_items + i; 4015 if (dr->dr_kind == DK_SUBSCRIPT) { 4016 if (tp->t_tspec != ARRAY) 4017 goto proceed; /* silent error */ 4018 tp = tp->t_subt; 4019 offset_in_bits += (unsigned) dr->dr_subscript 4020 * type_size_in_bits(tp); 4021 } else { 4022 if (!is_struct_or_union(tp->t_tspec)) 4023 goto proceed; /* silent error */ 4024 const char *name = dr->dr_member->s_name; 4025 sym_t *mem = find_member(tp->u.sou, name); 4026 if (mem == NULL) { 4027 /* type '%s' does not have member '%s' */ 4028 error(101, name, type_name(tp)); 4029 goto proceed; 4030 } 4031 tp = mem->s_type; 4032 offset_in_bits += mem->u.s_member.sm_offset_in_bits; 4033 } 4034 } 4035 free(dn.dn_items); 4036 4037 proceed:; 4038 unsigned int offset_in_bytes = offset_in_bits / CHAR_SIZE; 4039 tnode_t *tn = build_integer_constant(SIZEOF_TSPEC, offset_in_bytes); 4040 tn->tn_system_dependent = true; 4041 return tn; 4042 } 4043 4044 unsigned int 4045 type_size_in_bits(const type_t *tp) 4046 { 4047 4048 unsigned int elem = 1; 4049 bool flex = false; 4050 lint_assert(tp != NULL); 4051 while (tp->t_tspec == ARRAY) { 4052 flex = true; /* allow c99 flex arrays [] [0] */ 4053 elem *= tp->u.dimension; 4054 tp = tp->t_subt; 4055 } 4056 if (elem == 0 && !flex) { 4057 /* cannot take size/alignment of incomplete type */ 4058 error(143); 4059 elem = 1; 4060 } 4061 4062 unsigned int elsz; 4063 switch (tp->t_tspec) { 4064 case VOID: 4065 /* cannot take size/alignment of void */ 4066 error(146); 4067 elsz = 1; 4068 break; 4069 case FUNC: 4070 /* cannot take size/alignment of function type '%s' */ 4071 error(144, type_name(tp)); 4072 elsz = 1; 4073 break; 4074 case STRUCT: 4075 case UNION: 4076 if (is_incomplete(tp)) { 4077 /* cannot take size/alignment of incomplete type */ 4078 error(143); 4079 elsz = 1; 4080 } else 4081 elsz = tp->u.sou->sou_size_in_bits; 4082 break; 4083 case ENUM: 4084 if (is_incomplete(tp)) { 4085 /* cannot take size/alignment of incomplete type */ 4086 warning(143); 4087 } 4088 /* FALLTHROUGH */ 4089 default: 4090 if (tp->t_bitfield) 4091 /* cannot take size/alignment of bit-field */ 4092 error(145); 4093 elsz = size_in_bits(tp->t_tspec); 4094 lint_assert(elsz > 0); 4095 break; 4096 } 4097 4098 return elem * elsz; 4099 } 4100 4101 /* C11 6.5.3.4, GCC */ 4102 tnode_t * 4103 build_alignof(const type_t *tp) 4104 { 4105 if (tp->t_tspec == FUNC) { 4106 /* cannot take size/alignment of function type '%s' */ 4107 error(144, type_name(tp)); 4108 return NULL; 4109 } 4110 if (tp->t_tspec == VOID) { 4111 /* cannot take size/alignment of void */ 4112 error(146); 4113 return NULL; 4114 } 4115 if (is_incomplete(tp)) { 4116 /* cannot take size/alignment of incomplete type */ 4117 error(143); 4118 return NULL; 4119 } 4120 if (tp->t_bitfield) { 4121 /* cannot take size/alignment of bit-field */ 4122 error(145); 4123 return NULL; 4124 } 4125 return build_integer_constant(SIZEOF_TSPEC, (int64_t)alignment(tp)); 4126 } 4127 4128 static tnode_t * 4129 cast_to_union(tnode_t *otn, bool sys, type_t *ntp) 4130 { 4131 4132 if (!allow_gcc) { 4133 /* union cast is a GCC extension */ 4134 error(328); 4135 return NULL; 4136 } 4137 4138 for (const sym_t *m = ntp->u.sou->sou_first_member; 4139 m != NULL; m = m->s_next) { 4140 if (types_compatible(m->s_type, otn->tn_type, 4141 false, false, NULL)) { 4142 tnode_t *ntn = build_op(CVT, sys, ntp, otn, NULL); 4143 ntn->tn_cast = true; 4144 return ntn; 4145 } 4146 } 4147 4148 /* type '%s' is not a member of '%s' */ 4149 error(329, type_name(otn->tn_type), type_name(ntp)); 4150 return NULL; 4151 } 4152 4153 // In GCC mode, allow 'nullptr + offset' as a constant expression. 4154 static tnode_t * 4155 null_pointer_offset(tnode_t *tn) 4156 { 4157 uint64_t off = 0; 4158 const tnode_t *n = tn; 4159 while ((n->tn_op == PLUS || n->tn_op == MINUS) 4160 && is_integer(n->u.ops.right->tn_type->t_tspec)) { 4161 off += (uint64_t)n->u.ops.right->u.value.u.integer; 4162 n = n->u.ops.left; 4163 } 4164 if (n->tn_type->t_tspec == PTR 4165 && n->tn_op == ADDR 4166 && n->u.ops.left->tn_op == INDIR 4167 && n->u.ops.left->u.ops.left->tn_op == CON 4168 && n->u.ops.left->u.ops.left->tn_type->t_tspec == PTR) { 4169 off += (uint64_t)n->u.ops.left->u.ops.left->u.value.u.integer; 4170 return build_integer_constant(SIZEOF_TSPEC, (int64_t)off); 4171 } 4172 return tn; 4173 } 4174 4175 tnode_t * 4176 cast(tnode_t *tn, bool sys, type_t *tp) 4177 { 4178 4179 if (tn == NULL) 4180 return NULL; 4181 4182 tn = cconv(tn); 4183 4184 lint_assert(tp != NULL); 4185 tspec_t nt = tp->t_tspec; 4186 tspec_t ot = tn->tn_type->t_tspec; 4187 4188 if (nt == VOID) { 4189 /* 4190 * C90 6.3.4, C99 6.5.4p2 and C11 6.5.4p2 allow any type to be 4191 * cast to void. The only other allowed casts are from a 4192 * scalar type to a scalar type. 4193 */ 4194 } else if (nt == UNION) 4195 return cast_to_union(tn, sys, tp); 4196 else if (nt == STRUCT || nt == ARRAY || nt == FUNC) { 4197 /* Casting to a struct is an undocumented GCC extension. */ 4198 if (!(allow_gcc && nt == STRUCT)) 4199 goto invalid_cast; 4200 } else if (is_struct_or_union(ot)) 4201 goto invalid_cast; 4202 else if (ot == VOID) { 4203 /* improper cast of void expression */ 4204 error(148); 4205 return NULL; 4206 } else if (is_integer(nt) && is_scalar(ot)) { 4207 tn = null_pointer_offset(tn); 4208 } else if (is_floating(nt) && is_arithmetic(ot)) { 4209 /* ok */ 4210 } else if (nt == PTR && is_integer(ot)) { 4211 /* ok */ 4212 } else if (nt == PTR && ot == PTR) { 4213 if (!tp->t_subt->t_const && tn->tn_type->t_subt->t_const) { 4214 if (hflag) 4215 /* cast discards 'const' from type '%s' */ 4216 warning(275, type_name(tn->tn_type)); 4217 } 4218 } else 4219 goto invalid_cast; 4220 4221 if (any_query_enabled 4222 && types_compatible(tp, tn->tn_type, false, false, NULL)) 4223 /* no-op cast from '%s' to '%s' */ 4224 query_message(6, type_name(tn->tn_type), type_name(tp)); 4225 4226 tn = convert(CVT, 0, tp, tn); 4227 tn->tn_cast = true; 4228 tn->tn_sys = sys; 4229 4230 return tn; 4231 4232 invalid_cast: 4233 /* invalid cast from '%s' to '%s' */ 4234 error(147, type_name(tn->tn_type), type_name(tp)); 4235 return NULL; 4236 } 4237 4238 void 4239 add_function_argument(function_call *call, tnode_t *arg) 4240 { 4241 /* 4242 * If there was a serious error in the expression for the argument, 4243 * create a dummy argument so the positions of the remaining arguments 4244 * will not change. 4245 */ 4246 if (arg == NULL) 4247 arg = build_integer_constant(INT, 0); 4248 4249 if (call->args_len >= call->args_cap) { 4250 call->args_cap += 8; 4251 tnode_t **new_args = expr_zero_alloc( 4252 call->args_cap * sizeof(*call->args), "tnode*[]"); 4253 if (call->args_len > 0) 4254 memcpy(new_args, call->args, 4255 call->args_len * sizeof(*call->args)); 4256 call->args = new_args; 4257 } 4258 call->args[call->args_len++] = arg; 4259 } 4260 4261 /* 4262 * Compare the type of an argument with the corresponding type of a 4263 * prototype parameter. If it is a valid combination, but both types 4264 * are not the same, insert a conversion to convert the argument into 4265 * the type of the parameter. 4266 */ 4267 static tnode_t * 4268 check_prototype_argument( 4269 int n, /* pos of arg */ 4270 type_t *tp, /* expected type (from prototype) */ 4271 tnode_t *tn) /* argument */ 4272 { 4273 tnode_t *ln = xcalloc(1, sizeof(*ln)); 4274 ln->tn_type = expr_unqualified_type(tp); 4275 ln->tn_lvalue = true; 4276 if (typeok(FARG, n, ln, tn)) { 4277 bool dowarn; 4278 if (!types_compatible(tp, tn->tn_type, 4279 true, false, (dowarn = false, &dowarn)) || dowarn) 4280 tn = convert(FARG, n, tp, tn); 4281 } 4282 free(ln); 4283 return tn; 4284 } 4285 4286 /* 4287 * Check types of all function arguments and insert conversions, 4288 * if necessary. 4289 */ 4290 static void 4291 check_function_arguments(const function_call *call) 4292 { 4293 type_t *ftp = call->func->tn_type->t_subt; 4294 4295 /* get # of parameters in the prototype */ 4296 int npar = 0; 4297 for (const sym_t *p = ftp->u.params; p != NULL; p = p->s_next) 4298 npar++; 4299 4300 int narg = (int)call->args_len; 4301 4302 const sym_t *param = ftp->u.params; 4303 if (ftp->t_proto && npar != narg && !(ftp->t_vararg && npar < narg)) { 4304 /* argument mismatch: %d %s passed, %d expected */ 4305 error(150, narg, narg != 1 ? "arguments" : "argument", npar); 4306 param = NULL; 4307 } 4308 4309 for (int i = 0; i < narg; i++) { 4310 tnode_t *arg = call->args[i]; 4311 4312 /* some things which are always not allowed */ 4313 tspec_t at = arg->tn_type->t_tspec; 4314 if (at == VOID) { 4315 /* void expressions may not be arguments, arg #%d */ 4316 error(151, i + 1); 4317 return; 4318 } 4319 if (is_struct_or_union(at) && is_incomplete(arg->tn_type)) { 4320 /* argument cannot have unknown size, arg #%d */ 4321 error(152, i + 1); 4322 return; 4323 } 4324 if (is_integer(at) && 4325 arg->tn_type->t_is_enum && 4326 is_incomplete(arg->tn_type)) { 4327 /* argument cannot have unknown size, arg #%d */ 4328 warning(152, i + 1); 4329 } 4330 4331 arg = cconv(arg); 4332 call->args[i] = arg; 4333 4334 arg = param != NULL 4335 ? check_prototype_argument(i + 1, param->s_type, arg) 4336 : promote(NOOP, true, arg); 4337 call->args[i] = arg; 4338 4339 if (param != NULL) 4340 param = param->s_next; 4341 } 4342 } 4343 4344 tnode_t * 4345 build_function_call(tnode_t *func, bool sys, function_call *call) 4346 { 4347 4348 if (func == NULL) 4349 return NULL; 4350 4351 call->func = func; 4352 check_ctype_function_call(call); 4353 4354 func = cconv(func); 4355 call->func = func; 4356 4357 if (func->tn_type->t_tspec != PTR || 4358 func->tn_type->t_subt->t_tspec != FUNC) { 4359 /* cannot call '%s', must be a function */ 4360 error(149, type_name(func->tn_type)); 4361 return NULL; 4362 } 4363 4364 check_function_arguments(call); 4365 4366 tnode_t *ntn = expr_alloc_tnode(); 4367 ntn->tn_op = CALL; 4368 ntn->tn_type = func->tn_type->t_subt->t_subt; 4369 ntn->tn_sys = sys; 4370 ntn->u.call = call; 4371 return ntn; 4372 } 4373 4374 /* 4375 * Return the value of an integral constant expression. 4376 * If the expression is not constant or its type is not an integer 4377 * type, an error message is printed. 4378 */ 4379 val_t * 4380 integer_constant(tnode_t *tn, bool required) 4381 { 4382 4383 if (tn != NULL) 4384 tn = cconv(tn); 4385 if (tn != NULL) 4386 tn = promote(NOOP, false, tn); 4387 4388 val_t *v = xcalloc(1, sizeof(*v)); 4389 4390 if (tn == NULL) { 4391 lint_assert(seen_error); 4392 debug_step("constant node is null; returning 1 instead"); 4393 v->v_tspec = INT; 4394 v->u.integer = 1; 4395 return v; 4396 } 4397 4398 v->v_tspec = tn->tn_type->t_tspec; 4399 4400 if (tn->tn_op == CON) { 4401 lint_assert(tn->tn_type->t_tspec == tn->u.value.v_tspec); 4402 if (is_integer(tn->u.value.v_tspec)) { 4403 v->v_unsigned_since_c90 = 4404 tn->u.value.v_unsigned_since_c90; 4405 v->u.integer = tn->u.value.u.integer; 4406 return v; 4407 } 4408 v->u.integer = (int64_t)tn->u.value.u.floating; 4409 } else 4410 v->u.integer = 1; 4411 4412 if (required) 4413 /* integral constant expression expected */ 4414 error(55); 4415 else 4416 /* variable array dimension is a C99/GCC extension */ 4417 c99ism(318); 4418 4419 if (!is_integer(v->v_tspec)) 4420 v->v_tspec = INT; 4421 4422 return v; 4423 } 4424 4425 static bool 4426 is_constcond_false(const tnode_t *tn, tspec_t t) 4427 { 4428 return (t == BOOL || t == INT) && 4429 tn->tn_op == CON && tn->u.value.u.integer == 0; 4430 } 4431 4432 /* 4433 * Perform some tests on expressions which can't be done in build_binary() 4434 * and functions called by build_binary(). These tests must be done here 4435 * because we need some information about the context in which the operations 4436 * are performed. 4437 * After all tests are performed and dofreeblk is true, expr() frees the 4438 * memory which is used for the expression. 4439 */ 4440 void 4441 expr(tnode_t *tn, bool vctx, bool cond, bool dofreeblk, bool is_do_while) 4442 { 4443 4444 if (tn == NULL) { /* in case of errors */ 4445 expr_free_all(); 4446 return; 4447 } 4448 4449 /* expr() is also called in global initializations */ 4450 if (dcs->d_kind != DLK_EXTERN && !is_do_while) 4451 check_statement_reachable(); 4452 4453 check_expr_misc(tn, vctx, cond, !cond, false, false, false); 4454 if (tn->tn_op == ASSIGN && !tn->tn_parenthesized) { 4455 if (hflag && cond) 4456 /* assignment in conditional context */ 4457 warning(159); 4458 } else if (tn->tn_op == CON) { 4459 if (hflag && cond && !suppress_constcond && 4460 !tn->tn_system_dependent && 4461 !(is_do_while && 4462 is_constcond_false(tn, tn->tn_type->t_tspec))) 4463 /* constant in conditional context */ 4464 warning(161); 4465 } 4466 if (!modtab[tn->tn_op].m_has_side_effect) { 4467 /* 4468 * for left operands of COMMA this warning is already printed 4469 */ 4470 if (tn->tn_op != COMMA && !vctx && !cond) 4471 check_null_effect(tn); 4472 } 4473 debug_node(tn); 4474 4475 if (dofreeblk) 4476 expr_free_all(); 4477 } 4478 4479 /* If the expression has the form '*(arr + idx)', check the array index. */ 4480 static void 4481 check_array_index(const tnode_t *indir, bool taking_address) 4482 { 4483 const tnode_t *plus, *arr, *idx; 4484 4485 if (indir->tn_op == INDIR 4486 && (plus = indir->u.ops.left, plus->tn_op == PLUS) 4487 && plus->u.ops.left->tn_op == ADDR 4488 && (arr = plus->u.ops.left->u.ops.left, true) 4489 && (arr->tn_op == STRING || arr->tn_op == NAME) 4490 && arr->tn_type->t_tspec == ARRAY 4491 && (idx = plus->u.ops.right, idx->tn_op == CON) 4492 && (!is_incomplete(arr->tn_type) || idx->u.value.u.integer < 0)) 4493 goto proceed; 4494 return; 4495 4496 proceed:; 4497 int elsz = length_in_bits(arr->tn_type->t_subt, NULL); 4498 if (elsz == 0) 4499 return; 4500 elsz /= CHAR_SIZE; 4501 4502 /* Change the unit of the index from bytes to element size. */ 4503 int64_t con = is_uinteger(idx->tn_type->t_tspec) 4504 ? (int64_t)((uint64_t)idx->u.value.u.integer / elsz) 4505 : idx->u.value.u.integer / elsz; 4506 4507 int dim = arr->tn_type->u.dimension + (taking_address ? 1 : 0); 4508 4509 if (!is_uinteger(idx->tn_type->t_tspec) && con < 0) 4510 /* array subscript %jd cannot be negative */ 4511 warning(167, (intmax_t)con); 4512 else if (dim > 0 && (uint64_t)con >= (uint64_t)dim) 4513 /* array subscript %ju cannot be > %d */ 4514 warning(168, (uintmax_t)con, dim - 1); 4515 } 4516 4517 static void 4518 check_expr_addr(const tnode_t *ln, bool szof, bool fcall) 4519 { 4520 /* XXX: Taking warn_about_unreachable into account here feels wrong. */ 4521 if (ln->tn_op == NAME && (reached || !warn_about_unreachable)) { 4522 if (!szof) 4523 mark_as_set(ln->u.sym); 4524 mark_as_used(ln->u.sym, fcall, szof); 4525 } 4526 check_array_index(ln, true); 4527 } 4528 4529 /* 4530 * If there is an asm statement in one of the compound statements around, 4531 * there may be other side effects, so don't warn. 4532 */ 4533 static bool 4534 is_asm_around(void) 4535 { 4536 for (decl_level *dl = dcs; dl != NULL; dl = dl->d_enclosing) 4537 if (dl->d_asm) 4538 return true; 4539 return false; 4540 } 4541 4542 static void 4543 check_expr_side_effect(const tnode_t *ln, bool szof) 4544 { 4545 4546 /* XXX: Taking warn_about_unreachable into account here feels wrong. */ 4547 if (ln->tn_op == NAME && (reached || !warn_about_unreachable)) { 4548 scl_t sc = ln->u.sym->s_scl; 4549 if (sc != EXTERN && sc != STATIC && 4550 !ln->u.sym->s_set && !szof && !is_asm_around()) { 4551 /* '%s' may be used before set */ 4552 warning(158, ln->u.sym->s_name); 4553 mark_as_set(ln->u.sym); 4554 } 4555 mark_as_used(ln->u.sym, false, false); 4556 } 4557 } 4558 4559 static void 4560 check_expr_assign(const tnode_t *ln, bool szof) 4561 { 4562 /* XXX: Taking warn_about_unreachable into account here feels wrong. */ 4563 if (ln->tn_op == NAME && !szof && (reached || !warn_about_unreachable)) { 4564 mark_as_set(ln->u.sym); 4565 if (ln->u.sym->s_scl == EXTERN) 4566 outusg(ln->u.sym); 4567 } 4568 check_array_index(ln, false); 4569 } 4570 4571 static void 4572 check_expr_call(const tnode_t *tn, const tnode_t *ln, 4573 bool szof, bool vctx, bool cond, bool retval_discarded) 4574 { 4575 lint_assert(ln->tn_op == ADDR); 4576 lint_assert(ln->u.ops.left->tn_op == NAME); 4577 if (!szof && !is_compiler_builtin(ln->u.ops.left->u.sym->s_name)) 4578 outcall(tn, vctx || cond, retval_discarded); 4579 4580 const function_call *call = tn->u.call; 4581 if (call->args_len == 4 || call->args_len == 5) 4582 check_snprintb(call); 4583 } 4584 4585 static void 4586 check_expr_op(op_t op, const tnode_t *ln, bool szof, bool fcall, bool eqwarn) 4587 { 4588 switch (op) { 4589 case ADDR: 4590 check_expr_addr(ln, szof, fcall); 4591 break; 4592 case LOAD: 4593 check_array_index(ln, false); 4594 /* FALLTHROUGH */ 4595 case INCBEF: 4596 case DECBEF: 4597 case INCAFT: 4598 case DECAFT: 4599 case ADDASS: 4600 case SUBASS: 4601 case MULASS: 4602 case DIVASS: 4603 case MODASS: 4604 case ANDASS: 4605 case ORASS: 4606 case XORASS: 4607 case SHLASS: 4608 case SHRASS: 4609 case REAL: 4610 case IMAG: 4611 check_expr_side_effect(ln, szof); 4612 break; 4613 case ASSIGN: 4614 check_expr_assign(ln, szof); 4615 break; 4616 case EQ: 4617 if (hflag && eqwarn) 4618 /* operator '==' found where '=' was expected */ 4619 warning(160); 4620 break; 4621 default: 4622 break; 4623 } 4624 } 4625 4626 /* 4627 * vctx ??? 4628 * cond whether the expression is a condition that 4629 * will be compared with 0 4630 * eqwarn whether the operator '==' might be a 4631 * misspelled '=' 4632 * fcall whether the expression is a function call 4633 * retval_discarded whether the return value of a function call 4634 * is discarded; such calls will be analyzed by 4635 * lint2 in messages 4, 8 and 9 4636 * szof whether the expression is part of a sizeof 4637 * expression, which means that its value is 4638 * discarded since only the type is relevant 4639 */ 4640 void 4641 check_expr_misc(const tnode_t *tn, bool vctx, bool cond, 4642 bool eqwarn, bool fcall, bool retval_discarded, bool szof) 4643 { 4644 4645 if (tn == NULL) 4646 return; 4647 op_t op = tn->tn_op; 4648 if (op == NAME || op == CON || op == STRING) 4649 return; 4650 bool is_direct = op == CALL 4651 && tn->u.call->func->tn_op == ADDR 4652 && tn->u.call->func->u.ops.left->tn_op == NAME; 4653 if (op == CALL) { 4654 const function_call *call = tn->u.call; 4655 if (is_direct) 4656 check_expr_call(tn, call->func, 4657 szof, vctx, cond, retval_discarded); 4658 bool discard = op == CVT && tn->tn_type->t_tspec == VOID; 4659 check_expr_misc(call->func, false, false, false, is_direct, 4660 discard, szof); 4661 for (size_t i = 0, n = call->args_len; i < n; i++) 4662 check_expr_misc(call->args[i], 4663 true, false, false, false, false, szof); 4664 return; 4665 } 4666 4667 lint_assert(has_operands(tn)); 4668 tnode_t *ln = tn->u.ops.left; 4669 tnode_t *rn = tn->u.ops.right; 4670 check_expr_op(op, ln, szof, fcall, eqwarn); 4671 4672 const mod_t *mp = &modtab[op]; 4673 bool cvctx = mp->m_value_context; 4674 bool ccond = mp->m_compares_with_zero; 4675 bool eq = mp->m_warn_if_operand_eq && 4676 !ln->tn_parenthesized && 4677 rn != NULL && !rn->tn_parenthesized; 4678 4679 /* 4680 * Values of operands of ':' are not used if the type of at least 4681 * one of the operands (for GCC compatibility) is 'void'. 4682 * 4683 * XXX test/value context of QUEST should probably be used as 4684 * context for both operands of COLON. 4685 */ 4686 if (op == COLON && tn->tn_type->t_tspec == VOID) 4687 cvctx = ccond = false; 4688 bool discard = op == CVT && tn->tn_type->t_tspec == VOID; 4689 check_expr_misc(ln, cvctx, ccond, eq, is_direct, discard, szof); 4690 4691 switch (op) { 4692 case LOGAND: 4693 case LOGOR: 4694 check_expr_misc(rn, false, true, eq, false, false, szof); 4695 break; 4696 case COLON: 4697 check_expr_misc(rn, cvctx, ccond, eq, false, false, szof); 4698 break; 4699 case COMMA: 4700 check_expr_misc(rn, vctx, cond, false, false, false, szof); 4701 break; 4702 default: 4703 if (mp->m_binary) 4704 check_expr_misc(rn, true, false, eq, false, false, 4705 szof); 4706 break; 4707 } 4708 } 4709 4710 /* 4711 * Return whether the expression can be used for static initialization. 4712 * 4713 * Constant initialization expressions must be constant or an address 4714 * of a static object with an optional offset. In the first case, 4715 * the result is returned in *offsp. In the second case, the static 4716 * object is returned in *symp and the offset in *offsp. 4717 * 4718 * The expression can consist of PLUS, MINUS, ADDR, NAME, STRING and 4719 * CON. Type conversions are allowed if they do not change binary 4720 * representation (including width). 4721 * 4722 * C99 6.6 "Constant expressions" 4723 * C99 6.7.8p4 restricts initializers for static storage duration 4724 */ 4725 bool 4726 constant_addr(const tnode_t *tn, const sym_t **symp, ptrdiff_t *offsp) 4727 { 4728 const sym_t *sym; 4729 ptrdiff_t offs1, offs2; 4730 tspec_t t, ot; 4731 4732 switch (tn->tn_op) { 4733 case MINUS: 4734 if (tn->u.ops.right->tn_op == CVT) 4735 return constant_addr(tn->u.ops.right, symp, offsp); 4736 else if (tn->u.ops.right->tn_op != CON) 4737 return false; 4738 /* FALLTHROUGH */ 4739 case PLUS: 4740 offs1 = offs2 = 0; 4741 if (tn->u.ops.left->tn_op == CON) { 4742 offs1 = (ptrdiff_t)tn->u.ops.left->u.value.u.integer; 4743 if (!constant_addr(tn->u.ops.right, &sym, &offs2)) 4744 return false; 4745 } else if (tn->u.ops.right->tn_op == CON) { 4746 offs2 = (ptrdiff_t)tn->u.ops.right->u.value.u.integer; 4747 if (tn->tn_op == MINUS) 4748 offs2 = -offs2; 4749 if (!constant_addr(tn->u.ops.left, &sym, &offs1)) 4750 return false; 4751 } else { 4752 return false; 4753 } 4754 *symp = sym; 4755 *offsp = offs1 + offs2; 4756 return true; 4757 case ADDR: 4758 if (tn->u.ops.left->tn_op == NAME) { 4759 *symp = tn->u.ops.left->u.sym; 4760 *offsp = 0; 4761 return true; 4762 } else { 4763 /* 4764 * If this were the front end of a compiler, we would 4765 * return a label instead of 0, at least if 4766 * 'tn->u.ops.left->tn_op == STRING'. 4767 */ 4768 *symp = NULL; 4769 *offsp = 0; 4770 return true; 4771 } 4772 case CVT: 4773 t = tn->tn_type->t_tspec; 4774 ot = tn->u.ops.left->tn_type->t_tspec; 4775 if ((!is_integer(t) && t != PTR) || 4776 (!is_integer(ot) && ot != PTR)) { 4777 return false; 4778 } 4779 #if 0 4780 /*- 4781 * consider: 4782 * struct foo { 4783 * unsigned char a; 4784 * } f = { 4785 * (unsigned char)(unsigned long) 4786 * (&(((struct foo *)0)->a)) 4787 * }; 4788 * since psize(unsigned long) != psize(unsigned char), 4789 * this fails. 4790 */ 4791 else if (psize(t) != psize(ot)) 4792 return -1; 4793 #endif 4794 return constant_addr(tn->u.ops.left, symp, offsp); 4795 default: 4796 return false; 4797 } 4798 } 4799 4800 /* Append s2 to s1, then free s2. */ 4801 buffer * 4802 cat_strings(buffer *s1, buffer *s2) 4803 { 4804 4805 if ((s1->data != NULL) != (s2->data != NULL)) { 4806 /* cannot concatenate wide and regular string literals */ 4807 error(292); 4808 return s1; 4809 } 4810 4811 if (s1->data != NULL) { 4812 while (s1->len + s2->len + 1 > s1->cap) 4813 s1->cap *= 2; 4814 s1->data = xrealloc(s1->data, s1->cap); 4815 memcpy(s1->data + s1->len, s2->data, s2->len + 1); 4816 free(s2->data); 4817 } 4818 s1->len += s2->len; 4819 free(s2); 4820 4821 return s1; 4822 } 4823 4824 4825 typedef struct stmt_expr { 4826 memory_pool se_mem; 4827 sym_t *se_sym; 4828 struct stmt_expr *se_enclosing; 4829 } stmt_expr; 4830 4831 static stmt_expr *stmt_exprs; 4832 4833 void 4834 begin_statement_expr(void) 4835 { 4836 debug_enter(); 4837 4838 stmt_expr *se = xmalloc(sizeof(*se)); 4839 se->se_mem = expr_save_memory(); 4840 se->se_sym = NULL; 4841 se->se_enclosing = stmt_exprs; 4842 stmt_exprs = se; 4843 } 4844 4845 void 4846 do_statement_expr(tnode_t *tn) 4847 { 4848 block_level--; 4849 mem_block_level--; 4850 stmt_exprs->se_sym = tn != NULL 4851 ? mktempsym(block_dup_type(tn->tn_type)) 4852 : NULL; /* after a syntax error */ 4853 mem_block_level++; 4854 block_level++; 4855 /* '({ ... })' is a GCC extension */ 4856 gnuism(320); 4857 } 4858 4859 tnode_t * 4860 end_statement_expr(void) 4861 { 4862 tnode_t *tn; 4863 4864 stmt_expr *se = stmt_exprs; 4865 if (se->se_sym == NULL) { 4866 tn = NULL; /* after a syntax error */ 4867 goto end; 4868 } 4869 4870 tn = build_name(se->se_sym, false); 4871 (void)expr_save_memory(); /* leak */ 4872 expr_restore_memory(se->se_mem); 4873 stmt_exprs = se->se_enclosing; 4874 free(se); 4875 4876 end: 4877 debug_leave(); 4878 return tn; 4879 } 4880 4881 bool 4882 in_statement_expr(void) 4883 { 4884 return stmt_exprs != NULL; 4885 } 4886
Indexes created Mon Sep 22 13:09:51 GMT 2025