tree.c revision 1.659
1 /* $NetBSD: tree.c,v 1.659 2024/11/23 00:01:48 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 1.659 2024/11/23 00:01:48 rillig Exp $"); 41 #endif 42 43 #include <float.h> 44 #include <limits.h> 45 #include <math.h> 46 #include <signal.h> 47 #include <stdlib.h> 48 #include <string.h> 49 50 #include "lint1.h" 51 52 53 typedef struct integer_constraints { 54 int64_t smin; /* signed minimum */ 55 int64_t smax; /* signed maximum */ 56 uint64_t umin; /* unsigned minimum */ 57 uint64_t umax; /* unsigned maximum */ 58 uint64_t bclr; /* bits that are definitely clear */ 59 } integer_constraints; 60 61 62 static int64_t 63 s64_min(int64_t a, int64_t b) 64 { 65 return a < b ? a : b; 66 } 67 68 static int64_t 69 s64_max(int64_t a, int64_t b) 70 { 71 return a > b ? a : b; 72 } 73 74 static uint64_t 75 s64_abs(int64_t x) 76 { 77 return x >= 0 ? (uint64_t)x : -(uint64_t)x; 78 } 79 80 static uint64_t 81 u64_max(uint64_t a, uint64_t b) 82 { 83 return a > b ? a : b; 84 } 85 86 static uint64_t 87 u64_fill_right(uint64_t x) 88 { 89 x |= x >> 1; 90 x |= x >> 2; 91 x |= x >> 4; 92 x |= x >> 8; 93 x |= x >> 16; 94 x |= x >> 32; 95 return x; 96 } 97 98 static bool 99 str_ends_with(const char *haystack, const char *needle) 100 { 101 size_t hlen = strlen(haystack); 102 size_t nlen = strlen(needle); 103 104 return nlen <= hlen && 105 memcmp(haystack + hlen - nlen, needle, nlen) == 0; 106 } 107 108 static unsigned 109 width_in_bits(const type_t *tp) 110 { 111 112 lint_assert(is_integer(tp->t_tspec)); 113 return tp->t_bitfield 114 ? tp->t_bit_field_width 115 : size_in_bits(tp->t_tspec); 116 } 117 118 static int 119 portable_rank_cmp(tspec_t t1, tspec_t t2) 120 { 121 const ttab_t *p1 = type_properties(t1), *p2 = type_properties(t2); 122 lint_assert(p1->tt_rank_kind == p2->tt_rank_kind); 123 lint_assert(p1->tt_rank_value > 0); 124 lint_assert(p2->tt_rank_value > 0); 125 return (int)p1->tt_rank_value - (int)p2->tt_rank_value; 126 } 127 128 static bool 129 ic_maybe_signed(const type_t *tp, const integer_constraints *ic) 130 { 131 return !is_uinteger(tp->t_tspec) && ic->bclr >> 63 == 0; 132 } 133 134 static integer_constraints 135 ic_any(const type_t *tp) 136 { 137 integer_constraints c; 138 139 uint64_t vbits = value_bits(width_in_bits(tp)); 140 if (is_uinteger(tp->t_tspec)) { 141 c.smin = INT64_MIN; 142 c.smax = INT64_MAX; 143 c.umin = 0; 144 c.umax = vbits; 145 c.bclr = ~c.umax; 146 } else { 147 c.smin = (int64_t)-1 - (int64_t)(vbits >> 1); 148 c.smax = (int64_t)(vbits >> 1); 149 c.umin = 0; 150 c.umax = UINT64_MAX; 151 c.bclr = 0; 152 } 153 return c; 154 } 155 156 static integer_constraints 157 ic_mult(const type_t *tp, integer_constraints a, integer_constraints b) 158 { 159 integer_constraints c; 160 161 if (ic_maybe_signed(tp, &a) || ic_maybe_signed(tp, &b) 162 || (a.umax > 0 && b.umax > ic_any(tp).umax / a.umax)) 163 return ic_any(tp); 164 165 c.smin = INT64_MIN; 166 c.smax = INT64_MAX; 167 c.umin = a.umin * b.umin; 168 c.umax = a.umax * b.umax; 169 c.bclr = ~u64_fill_right(c.umax); 170 return c; 171 } 172 173 static integer_constraints 174 ic_div(const type_t *tp, integer_constraints a, integer_constraints b) 175 { 176 integer_constraints c; 177 178 if (ic_maybe_signed(tp, &a) || ic_maybe_signed(tp, &b) || b.umin == 0) 179 return ic_any(tp); 180 181 c.smin = INT64_MIN; 182 c.smax = INT64_MAX; 183 c.umin = a.umin / b.umax; 184 c.umax = a.umax / b.umin; 185 c.bclr = ~u64_fill_right(c.umax); 186 return c; 187 } 188 189 static integer_constraints 190 ic_mod_signed(integer_constraints a, integer_constraints b) 191 { 192 integer_constraints c; 193 194 uint64_t max_abs_b = u64_max(s64_abs(b.smin), s64_abs(b.smax)); 195 if (max_abs_b >> 63 != 0 || max_abs_b == 0) 196 return a; 197 c.smin = s64_max(a.smin, -(int64_t)(max_abs_b - 1)); 198 c.smax = s64_min(a.smax, (int64_t)(max_abs_b - 1)); 199 c.umin = 0; 200 c.umax = UINT64_MAX; 201 c.bclr = 0; 202 return c; 203 } 204 205 static integer_constraints 206 ic_mod(const type_t *tp, integer_constraints a, integer_constraints b) 207 { 208 integer_constraints c; 209 210 if (ic_maybe_signed(tp, &a) || ic_maybe_signed(tp, &b)) 211 return ic_mod_signed(a, b); 212 213 c.smin = INT64_MIN; 214 c.smax = INT64_MAX; 215 c.umin = 0; 216 c.umax = b.umax - 1; 217 c.bclr = ~u64_fill_right(c.umax); 218 return c; 219 } 220 221 static integer_constraints 222 ic_shl(const type_t *tp, integer_constraints a, integer_constraints b) 223 { 224 integer_constraints c; 225 unsigned int amount; 226 227 if (ic_maybe_signed(tp, &a)) 228 return ic_any(tp); 229 230 if (b.smin == b.smax && b.smin >= 0 && b.smin < 64) 231 amount = (unsigned int)b.smin; 232 else if (b.umin == b.umax && b.umin < 64) 233 amount = (unsigned int)b.umin; 234 else 235 return ic_any(tp); 236 237 c.smin = INT64_MIN; 238 c.smax = INT64_MAX; 239 c.umin = 0; 240 c.umax = UINT64_MAX; 241 c.bclr = a.bclr << amount | (((uint64_t)1 << amount) - 1); 242 return c; 243 } 244 245 static integer_constraints 246 ic_shr(const type_t *tp, integer_constraints a, integer_constraints b) 247 { 248 integer_constraints c; 249 unsigned int amount; 250 251 if (ic_maybe_signed(tp, &a)) 252 return ic_any(tp); 253 254 if (b.smin == b.smax && b.smin >= 0 && b.smin < 64) 255 amount = (unsigned int)b.smin; 256 else if (b.umin == b.umax && b.umin < 64) 257 amount = (unsigned int)b.umin; 258 else 259 return ic_any(tp); 260 261 c.smin = INT64_MIN; 262 c.smax = INT64_MAX; 263 c.umin = 0; 264 c.umax = UINT64_MAX; 265 c.bclr = a.bclr >> amount | ~(~(uint64_t)0 >> amount); 266 return c; 267 } 268 269 static integer_constraints 270 ic_bitand(integer_constraints a, integer_constraints b) 271 { 272 integer_constraints c; 273 274 c.smin = INT64_MIN; 275 c.smax = INT64_MAX; 276 c.umin = 0; 277 c.umax = ~(a.bclr | b.bclr); 278 if (c.umax >> 63 == 0) { 279 c.smin = 0; 280 c.smax = (int64_t)c.umax; 281 } 282 c.bclr = a.bclr | b.bclr; 283 return c; 284 } 285 286 static integer_constraints 287 ic_bitor(integer_constraints a, integer_constraints b) 288 { 289 integer_constraints c; 290 291 c.smin = INT64_MIN; 292 c.smax = INT64_MAX; 293 c.umin = 0; 294 c.umax = ~(a.bclr & b.bclr); 295 c.bclr = a.bclr & b.bclr; 296 return c; 297 } 298 299 static integer_constraints 300 ic_quest_colon(integer_constraints a, integer_constraints b) 301 { 302 integer_constraints c; 303 304 c.smin = a.smin < b.smin ? a.smin : b.smin; 305 c.smax = a.smax > b.smax ? a.smax : b.smax; 306 c.umin = a.umin < b.umin ? a.umin : b.umin; 307 c.umax = a.umax > b.umax ? a.umax : b.umax; 308 c.bclr = a.bclr & b.bclr; 309 return c; 310 } 311 312 static integer_constraints 313 ic_con(const type_t *tp, const val_t *v) 314 { 315 integer_constraints c; 316 317 lint_assert(is_integer(tp->t_tspec)); 318 int64_t si = v->u.integer; 319 uint64_t ui = (uint64_t)si; 320 c.smin = si; 321 c.smax = si; 322 c.umin = ui; 323 c.umax = ui; 324 c.bclr = ~ui; 325 return c; 326 } 327 328 static integer_constraints 329 ic_cvt(const type_t *ntp, const type_t *otp, integer_constraints a) 330 { 331 unsigned nw = width_in_bits(ntp); 332 unsigned ow = width_in_bits(otp); 333 bool nu = is_uinteger(ntp->t_tspec); 334 bool ou = is_uinteger(otp->t_tspec); 335 336 if (nw >= ow && nu == ou) 337 return a; 338 if (nw > ow && ou) 339 return a; 340 return ic_any(ntp); 341 } 342 343 static integer_constraints 344 ic_expr(const tnode_t *tn) 345 { 346 integer_constraints lc, rc; 347 348 lint_assert(is_integer(tn->tn_type->t_tspec)); 349 350 switch (tn->tn_op) { 351 case MULT: 352 lc = ic_expr(before_conversion(tn->u.ops.left)); 353 rc = ic_expr(before_conversion(tn->u.ops.right)); 354 return ic_mult(tn->tn_type, lc, rc); 355 case DIV: 356 lc = ic_expr(before_conversion(tn->u.ops.left)); 357 rc = ic_expr(before_conversion(tn->u.ops.right)); 358 return ic_div(tn->tn_type, lc, rc); 359 case MOD: 360 lc = ic_expr(before_conversion(tn->u.ops.left)); 361 rc = ic_expr(before_conversion(tn->u.ops.right)); 362 return ic_mod(tn->tn_type, lc, rc); 363 case SHL: 364 lc = ic_expr(tn->u.ops.left); 365 rc = ic_expr(tn->u.ops.right); 366 return ic_shl(tn->tn_type, lc, rc); 367 case SHR: 368 lc = ic_expr(tn->u.ops.left); 369 rc = ic_expr(tn->u.ops.right); 370 return ic_shr(tn->tn_type, lc, rc); 371 case BITAND: 372 lc = ic_expr(tn->u.ops.left); 373 rc = ic_expr(tn->u.ops.right); 374 return ic_bitand(lc, rc); 375 case BITOR: 376 lc = ic_expr(tn->u.ops.left); 377 rc = ic_expr(tn->u.ops.right); 378 return ic_bitor(lc, rc); 379 case QUEST: 380 lc = ic_expr(tn->u.ops.right->u.ops.left); 381 rc = ic_expr(tn->u.ops.right->u.ops.right); 382 return ic_quest_colon(lc, rc); 383 case CON: 384 return ic_con(tn->tn_type, &tn->u.value); 385 case CVT: 386 if (!is_integer(tn->u.ops.left->tn_type->t_tspec)) 387 return ic_any(tn->tn_type); 388 lc = ic_expr(tn->u.ops.left); 389 return ic_cvt(tn->tn_type, tn->u.ops.left->tn_type, lc); 390 default: 391 return ic_any(tn->tn_type); 392 } 393 } 394 395 uint64_t 396 possible_bits(const tnode_t *tn) 397 { 398 return ~ic_expr(tn).bclr; 399 } 400 401 bool 402 attributes_contain(const attribute_list *attrs, const char *str) 403 { 404 for (size_t i = 0, n = attrs->len; i < n; i++) { 405 const attribute *attr = attrs->attrs + i; 406 if (attr->prefix == NULL && strcmp(attr->name, str) == 0) 407 return true; 408 } 409 return false; 410 } 411 412 /* Build 'pointer to tp', 'array of tp' or 'function returning tp'. */ 413 type_t * 414 block_derive_type(type_t *tp, tspec_t t) 415 { 416 417 type_t *tp2 = block_zero_alloc(sizeof(*tp2), "type"); 418 tp2->t_tspec = t; 419 tp2->t_subt = tp; 420 return tp2; 421 } 422 423 /* 424 * Derive 'pointer to tp' or 'function returning tp'. 425 * The memory is freed at the end of the current expression. 426 */ 427 type_t * 428 expr_derive_type(type_t *tp, tspec_t t) 429 { 430 431 type_t *tp2 = expr_zero_alloc(sizeof(*tp2), "type"); 432 tp2->t_tspec = t; 433 tp2->t_subt = tp; 434 return tp2; 435 } 436 437 /* Create an expression from a unary or binary operator and its operands. */ 438 static tnode_t * 439 build_op(op_t op, bool sys, type_t *type, tnode_t *ln, tnode_t *rn) 440 { 441 442 tnode_t *ntn = expr_alloc_tnode(); 443 ntn->tn_op = op; 444 ntn->tn_type = type; 445 ntn->tn_sys = sys; 446 ntn->u.ops.left = ln; 447 ntn->u.ops.right = rn; 448 449 if (op == INDIR || op == FSEL) { 450 lint_assert(ln->tn_type->t_tspec == PTR); 451 tspec_t t = ln->tn_type->t_subt->t_tspec; 452 ntn->tn_lvalue = t != FUNC && t != VOID; 453 } 454 455 return ntn; 456 } 457 458 tnode_t * 459 build_constant(type_t *tp, val_t *v) 460 { 461 462 tnode_t *n = expr_alloc_tnode(); 463 n->tn_op = CON; 464 n->tn_type = tp; 465 n->u.value = *v; 466 n->u.value.v_tspec = tp->t_tspec; 467 free(v); 468 return n; 469 } 470 471 static tnode_t * 472 build_integer_constant(tspec_t t, int64_t si) 473 { 474 475 tnode_t *n = expr_alloc_tnode(); 476 n->tn_op = CON; 477 n->tn_type = gettyp(t); 478 n->u.value.v_tspec = t; 479 n->u.value.v_unsigned_since_c90 = false; 480 n->u.value.v_char_constant = false; 481 n->u.value.u.integer = si; 482 return n; 483 } 484 485 static void 486 fallback_symbol(sym_t *sym) 487 { 488 489 if (Tflag && fallback_symbol_strict_bool(sym)) 490 return; 491 492 if (funcsym != NULL && (strcmp(sym->s_name, "__FUNCTION__") == 0 || 493 strcmp(sym->s_name, "__PRETTY_FUNCTION__") == 0)) { 494 /* __FUNCTION__/__PRETTY_FUNCTION__ is a GCC extension */ 495 gnuism(316); 496 goto return_function_name; 497 } 498 499 if (funcsym != NULL && strcmp(sym->s_name, "__func__") == 0) { 500 if (!allow_c99) 501 /* __func__ is a C99 feature */ 502 warning(317); 503 /* C11 6.4.2.2 */ 504 return_function_name: 505 sym->s_type = block_derive_type(gettyp(CHAR), ARRAY); 506 sym->s_type->t_const = true; 507 sym->s_type->u.dimension = (int)strlen(funcsym->s_name) + 1; 508 return; 509 } 510 511 /* '%s' undefined */ 512 error(99, sym->s_name); 513 } 514 515 /* 516 * Functions that are predeclared by GCC or other compilers can be called 517 * with arbitrary arguments. Since lint usually runs after a successful 518 * compilation, it's the compiler's job to catch any errors. 519 */ 520 bool 521 is_compiler_builtin(const char *name) 522 { 523 /* https://gcc.gnu.org/onlinedocs/gcc/C-Extensions.html */ 524 if (allow_gcc) { 525 if (strncmp(name, "__atomic_", 9) == 0 || 526 strncmp(name, "__builtin_", 10) == 0 || 527 strcmp(name, "alloca") == 0 || 528 /* obsolete but still in use, as of 2021 */ 529 strncmp(name, "__sync_", 7) == 0) 530 return true; 531 } 532 533 /* https://software.intel.com/sites/landingpage/IntrinsicsGuide/ */ 534 if (strncmp(name, "_mm_", 4) == 0) 535 return true; 536 537 return false; 538 } 539 540 /* https://gcc.gnu.org/onlinedocs/gcc/Integer-Overflow-Builtins.html */ 541 static bool 542 is_gcc_bool_builtin(const char *name) 543 { 544 return strncmp(name, "__builtin_", 10) == 0 && 545 (str_ends_with(name, "_overflow") || 546 str_ends_with(name, "_overflow_p")); 547 } 548 549 static void 550 build_name_call(sym_t *sym) 551 { 552 553 if (is_compiler_builtin(sym->s_name)) { 554 /* 555 * Do not warn about these, just assume that they are regular 556 * functions compatible with non-prototype calling conventions. 557 */ 558 if (allow_gcc && is_gcc_bool_builtin(sym->s_name)) 559 sym->s_type = gettyp(BOOL); 560 } else if (allow_c99) 561 /* function '%s' implicitly declared to return int */ 562 error(215, sym->s_name); 563 else if (!allow_trad) 564 /* function '%s' implicitly declared to return int */ 565 warning(215, sym->s_name); 566 567 /* XXX if !allow_c90, the symbol should be exported to level 0 */ 568 sym->s_type = block_derive_type(sym->s_type, FUNC); 569 } 570 571 /* Create a node for a name (symbol table entry). */ 572 tnode_t * 573 build_name(sym_t *sym, bool is_funcname) 574 { 575 576 if (sym->s_scl == NO_SCL && !in_gcc_attribute) { 577 sym->s_scl = EXTERN; 578 sym->s_def = DECL; 579 if (is_funcname) 580 build_name_call(sym); 581 else 582 fallback_symbol(sym); 583 } 584 585 lint_assert(sym->s_kind == SK_VCFT || sym->s_kind == SK_MEMBER); 586 587 tnode_t *n = expr_alloc_tnode(); 588 n->tn_type = sym->s_type; 589 if (sym->s_scl == BOOL_CONST) { 590 n->tn_op = CON; 591 n->u.value.v_tspec = BOOL; 592 n->u.value.v_unsigned_since_c90 = false; 593 n->u.value.v_char_constant = false; 594 n->u.value.u.integer = sym->u.s_bool_constant ? 1 : 0; 595 } else if (sym->s_scl == ENUM_CONST) { 596 n->tn_op = CON; 597 n->u.value.v_tspec = INT; /* ENUM is in n->tn_type */ 598 n->u.value.v_unsigned_since_c90 = false; 599 n->u.value.v_char_constant = false; 600 n->u.value.u.integer = sym->u.s_enum_constant; 601 } else { 602 n->tn_op = NAME; 603 n->u.sym = sym; 604 if (sym->s_kind == SK_VCFT && sym->s_type->t_tspec != FUNC) 605 n->tn_lvalue = true; 606 } 607 608 return n; 609 } 610 611 tnode_t * 612 build_string(buffer *lit) 613 { 614 size_t value_len = lit->len; 615 if (lit->data != NULL) { 616 quoted_iterator it = { .end = 0 }; 617 for (value_len = 0; quoted_next(lit, &it); value_len++) 618 continue; 619 } 620 621 type_t *tp = expr_zero_alloc(sizeof(*tp), "type"); 622 tp->t_tspec = ARRAY; 623 tp->t_subt = gettyp(lit->data != NULL ? CHAR : WCHAR_TSPEC); 624 tp->u.dimension = (int)(value_len + 1); 625 626 tnode_t *n = expr_alloc_tnode(); 627 n->tn_op = STRING; 628 n->tn_type = tp; 629 n->tn_lvalue = true; 630 631 n->u.str_literals = expr_zero_alloc(sizeof(*n->u.str_literals), "tnode.string"); 632 n->u.str_literals->len = lit->len; 633 634 if (lit->data != NULL) { 635 n->u.str_literals->data = expr_zero_alloc(lit->len + 1, 636 "tnode.string.data"); 637 (void)memcpy(n->u.str_literals->data, lit->data, lit->len + 1); 638 free(lit->data); 639 } 640 free(lit); 641 642 return n; 643 } 644 645 tnode_t * 646 build_generic_selection(const tnode_t *expr, 647 struct generic_association *sel) 648 { 649 tnode_t *default_result = NULL; 650 651 for (; sel != NULL; sel = sel->ga_prev) { 652 if (expr != NULL && 653 types_compatible(sel->ga_arg, expr->tn_type, 654 false, false, NULL)) 655 return sel->ga_result; 656 else if (sel->ga_arg == NULL) 657 default_result = sel->ga_result; 658 } 659 return default_result; 660 } 661 662 static bool 663 is_out_of_char_range(const tnode_t *tn) 664 { 665 return tn->tn_op == CON && 666 !tn->u.value.v_char_constant && 667 !(0 <= tn->u.value.u.integer && 668 tn->u.value.u.integer < 1 << (CHAR_SIZE - 1)); 669 } 670 671 static bool 672 check_nonportable_char_comparison(op_t op, 673 const tnode_t *ln, tspec_t lt, 674 const tnode_t *rn, tspec_t rt) 675 { 676 if (!(hflag || pflag)) 677 return true; 678 679 if (lt == CHAR && is_out_of_char_range(rn)) { 680 char buf[128]; 681 (void)snprintf(buf, sizeof(buf), "%s %d", 682 op_name(op), (int)rn->u.value.u.integer); 683 /* nonportable character comparison '%s' */ 684 warning(230, buf); 685 return false; 686 } 687 if (rt == CHAR && is_out_of_char_range(ln)) { 688 char buf[128]; 689 (void)snprintf(buf, sizeof(buf), "%d %s ?", 690 (int)ln->u.value.u.integer, op_name(op)); 691 /* nonportable character comparison '%s' */ 692 warning(230, buf); 693 return false; 694 } 695 return true; 696 } 697 698 static void 699 check_integer_comparison(op_t op, tnode_t *ln, tnode_t *rn) 700 { 701 702 tspec_t lt = ln->tn_type->t_tspec; 703 tspec_t rt = rn->tn_type->t_tspec; 704 705 if (ln->tn_op != CON && rn->tn_op != CON) 706 return; 707 708 if (!is_integer(lt) || !is_integer(rt)) 709 return; 710 711 if (any_query_enabled && !in_system_header) { 712 if (lt == CHAR && rn->tn_op == CON && 713 !rn->u.value.v_char_constant) { 714 /* comparison '%s' of 'char' with plain integer %d */ 715 query_message(14, 716 op_name(op), (int)rn->u.value.u.integer); 717 } 718 if (rt == CHAR && ln->tn_op == CON && 719 !ln->u.value.v_char_constant) { 720 /* comparison '%s' of 'char' with plain integer %d */ 721 query_message(14, 722 op_name(op), (int)ln->u.value.u.integer); 723 } 724 } 725 726 if (!check_nonportable_char_comparison(op, ln, lt, rn, rt)) 727 return; 728 729 if (is_uinteger(lt) && !is_uinteger(rt) && 730 rn->tn_op == CON && rn->u.value.u.integer <= 0) { 731 if (rn->u.value.u.integer < 0) { 732 /* operator '%s' compares '%s' with '%s' */ 733 warning(162, op_name(op), 734 type_name(ln->tn_type), "negative constant"); 735 } else if (op == LT || op == GE) 736 /* operator '%s' compares '%s' with '%s' */ 737 warning(162, op_name(op), type_name(ln->tn_type), "0"); 738 return; 739 } 740 if (is_uinteger(rt) && !is_uinteger(lt) && 741 ln->tn_op == CON && ln->u.value.u.integer <= 0) { 742 if (ln->u.value.u.integer < 0) { 743 /* operator '%s' compares '%s' with '%s' */ 744 warning(162, op_name(op), 745 "negative constant", type_name(rn->tn_type)); 746 } else if (op == GT || op == LE) 747 /* operator '%s' compares '%s' with '%s' */ 748 warning(162, op_name(op), "0", type_name(rn->tn_type)); 749 return; 750 } 751 } 752 753 static const tspec_t arith_rank[] = { 754 LDOUBLE, DOUBLE, FLOAT, 755 #ifdef INT128_SIZE 756 UINT128, INT128, 757 #endif 758 ULLONG, LLONG, 759 ULONG, LONG, 760 UINT, INT, 761 }; 762 763 /* Keep unsigned in traditional C */ 764 static tspec_t 765 usual_arithmetic_conversion_trad(tspec_t lt, tspec_t rt) 766 { 767 768 size_t i; 769 for (i = 0; arith_rank[i] != INT; i++) 770 if (lt == arith_rank[i] || rt == arith_rank[i]) 771 break; 772 773 tspec_t t = arith_rank[i]; 774 if (is_uinteger(lt) || is_uinteger(rt)) 775 if (is_integer(t) && !is_uinteger(t)) 776 return unsigned_type(t); 777 return t; 778 } 779 780 static tspec_t 781 usual_arithmetic_conversion_c90(tspec_t lt, tspec_t rt) 782 { 783 784 if (lt == rt) 785 return lt; 786 787 if (lt == LCOMPLEX || rt == LCOMPLEX) 788 return LCOMPLEX; 789 if (lt == DCOMPLEX || rt == DCOMPLEX) 790 return DCOMPLEX; 791 if (lt == FCOMPLEX || rt == FCOMPLEX) 792 return FCOMPLEX; 793 if (lt == LDOUBLE || rt == LDOUBLE) 794 return LDOUBLE; 795 if (lt == DOUBLE || rt == DOUBLE) 796 return DOUBLE; 797 if (lt == FLOAT || rt == FLOAT) 798 return FLOAT; 799 800 if (size_in_bits(lt) > size_in_bits(rt)) 801 return lt; 802 if (size_in_bits(lt) < size_in_bits(rt)) 803 return rt; 804 805 size_t i; 806 for (i = 3; arith_rank[i] != INT; i++) 807 if (arith_rank[i] == lt || arith_rank[i] == rt) 808 break; 809 if ((is_uinteger(lt) || is_uinteger(rt)) && 810 !is_uinteger(arith_rank[i])) 811 i--; 812 return arith_rank[i]; 813 } 814 815 static tnode_t * 816 apply_usual_arithmetic_conversions(op_t op, tnode_t *tn, tspec_t t) 817 { 818 type_t *ntp = expr_dup_type(tn->tn_type); 819 ntp->t_tspec = t; 820 if (tn->tn_op != CON) { 821 /* usual arithmetic conversion for '%s' from '%s' to '%s' */ 822 query_message(4, op_name(op), 823 type_name(tn->tn_type), type_name(ntp)); 824 } 825 return convert(op, 0, ntp, tn); 826 } 827 828 /* 829 * Apply the "usual arithmetic conversions" (C99 6.3.1.8), which gives both 830 * operands the same type. 831 */ 832 static void 833 balance(op_t op, tnode_t **lnp, tnode_t **rnp) 834 { 835 836 tspec_t lt = (*lnp)->tn_type->t_tspec; 837 tspec_t rt = (*rnp)->tn_type->t_tspec; 838 if (!is_arithmetic(lt) || !is_arithmetic(rt)) 839 return; 840 841 tspec_t t = allow_c90 842 ? usual_arithmetic_conversion_c90(lt, rt) 843 : usual_arithmetic_conversion_trad(lt, rt); 844 845 if (modtab[op].m_comparison 846 && is_integer(lt) && (*lnp)->tn_op != CON 847 && is_floating(t) && (*rnp)->tn_op == CON) 848 /* comparing integer '%s' to floating point constant %Lg */ 849 warning(379, type_name((*lnp)->tn_type), 850 (*rnp)->u.value.u.floating); 851 852 if (t != lt) 853 *lnp = apply_usual_arithmetic_conversions(op, *lnp, t); 854 if (t != rt) 855 *rnp = apply_usual_arithmetic_conversions(op, *rnp, t); 856 857 if (is_integer(t)) { 858 unsigned lw = width_in_bits((*lnp)->tn_type); 859 unsigned rw = width_in_bits((*rnp)->tn_type); 860 if (lw < rw) 861 *lnp = convert(NOOP, 0, (*rnp)->tn_type, *lnp); 862 if (rw < lw) 863 *rnp = convert(NOOP, 0, (*lnp)->tn_type, *rnp); 864 } 865 } 866 867 static tnode_t * 868 build_address(bool sys, tnode_t *tn, bool force) 869 { 870 tspec_t t; 871 872 if (!force && ((t = tn->tn_type->t_tspec) == ARRAY || t == FUNC)) { 873 if (!allow_c90) 874 /* '&' before array or function: ignored */ 875 warning(127); 876 return tn; 877 } 878 879 /* eliminate '&*' */ 880 if (tn->tn_op == INDIR && 881 tn->u.ops.left->tn_type->t_tspec == PTR && 882 tn->u.ops.left->tn_type->t_subt == tn->tn_type) { 883 return tn->u.ops.left; 884 } 885 886 return build_op(ADDR, sys, expr_derive_type(tn->tn_type, PTR), 887 tn, NULL); 888 } 889 890 static uint64_t 891 fold_unsigned_integer(op_t op, uint64_t l, uint64_t r, 892 uint64_t max_value, bool *overflow) 893 { 894 switch (op) { 895 case COMPL: 896 return ~l & max_value; 897 case UPLUS: 898 return +l; 899 case UMINUS: 900 return -l & max_value; 901 case MULT: 902 *overflow = r > 0 && l > max_value / r; 903 return l * r; 904 case DIV: 905 if (r == 0) { 906 /* division by 0 */ 907 error(139); 908 return max_value; 909 } 910 return l / r; 911 case MOD: 912 if (r == 0) { 913 /* modulus by 0 */ 914 error(140); 915 return 0; 916 } 917 return l % r; 918 case PLUS: 919 *overflow = l > max_value - r; 920 return l + r; 921 case MINUS: 922 *overflow = l < r; 923 return l - r; 924 case SHL: 925 /* TODO: warn about out-of-bounds 'r'. */ 926 /* TODO: warn about overflow. */ 927 return l << (r & 63); 928 case SHR: 929 /* TODO: warn about out-of-bounds 'r'. */ 930 return l >> (r & 63); 931 case LT: 932 return l < r ? 1 : 0; 933 case LE: 934 return l <= r ? 1 : 0; 935 case GT: 936 return l > r ? 1 : 0; 937 case GE: 938 return l >= r ? 1 : 0; 939 case EQ: 940 return l == r ? 1 : 0; 941 case NE: 942 return l != r ? 1 : 0; 943 case BITAND: 944 return l & r; 945 case BITXOR: 946 return l ^ r; 947 case BITOR: 948 return l | r; 949 default: 950 lint_assert(/*CONSTCOND*/false); 951 /* NOTREACHED */ 952 } 953 } 954 955 static int64_t 956 fold_signed_integer(op_t op, int64_t l, int64_t r, 957 int64_t min_value, int64_t max_value, bool *overflow) 958 { 959 switch (op) { 960 case COMPL: 961 return ~l; 962 case UPLUS: 963 return +l; 964 case UMINUS: 965 *overflow = l == min_value; 966 return *overflow ? l : -l; 967 case MULT:; 968 uint64_t al = l >= 0 ? (uint64_t)l : -(uint64_t)l; 969 uint64_t ar = r >= 0 ? (uint64_t)r : -(uint64_t)r; 970 bool neg = (l >= 0) != (r >= 0); 971 uint64_t max_prod = (uint64_t)max_value + (neg ? 1 : 0); 972 if (al > 0 && ar > max_prod / al) { 973 *overflow = true; 974 return neg ? min_value : max_value; 975 } 976 return l * r; 977 case DIV: 978 if (r == 0) { 979 /* division by 0 */ 980 error(139); 981 return max_value; 982 } 983 if (l == min_value && r == -1) { 984 *overflow = true; 985 return l; 986 } 987 return l / r; 988 case MOD: 989 if (r == 0) { 990 /* modulus by 0 */ 991 error(140); 992 return 0; 993 } 994 if (l == min_value && r == -1) { 995 *overflow = true; 996 return 0; 997 } 998 return l % r; 999 case PLUS: 1000 if (r > 0 && l > max_value - r) { 1001 *overflow = true; 1002 return max_value; 1003 } 1004 if (r < 0 && l < min_value - r) { 1005 *overflow = true; 1006 return min_value; 1007 } 1008 return l + r; 1009 case MINUS: 1010 if (r > 0 && l < min_value + r) { 1011 *overflow = true; 1012 return min_value; 1013 } 1014 if (r < 0 && l > max_value + r) { 1015 *overflow = true; 1016 return max_value; 1017 } 1018 return l - r; 1019 case SHL: 1020 /* TODO: warn about out-of-bounds 'r'. */ 1021 /* TODO: warn about overflow. */ 1022 return l << (r & 63); 1023 case SHR: 1024 /* TODO: warn about out-of-bounds 'r'. */ 1025 if (l < 0) 1026 return (int64_t)~(~(uint64_t)l >> (r & 63)); 1027 return (int64_t)((uint64_t)l >> (r & 63)); 1028 case LT: 1029 return l < r ? 1 : 0; 1030 case LE: 1031 return l <= r ? 1 : 0; 1032 case GT: 1033 return l > r ? 1 : 0; 1034 case GE: 1035 return l >= r ? 1 : 0; 1036 case EQ: 1037 return l == r ? 1 : 0; 1038 case NE: 1039 return l != r ? 1 : 0; 1040 case BITAND: 1041 return l & r; 1042 case BITXOR: 1043 return l ^ r; 1044 case BITOR: 1045 return l | r; 1046 default: 1047 lint_assert(/*CONSTCOND*/false); 1048 /* NOTREACHED */ 1049 } 1050 } 1051 1052 static tnode_t * 1053 fold_constant_integer(tnode_t *tn) 1054 { 1055 1056 lint_assert(has_operands(tn)); 1057 tspec_t t = tn->u.ops.left->tn_type->t_tspec; 1058 int64_t l = tn->u.ops.left->u.value.u.integer; 1059 int64_t r = is_binary(tn) ? tn->u.ops.right->u.value.u.integer : 0; 1060 uint64_t mask = value_bits(size_in_bits(t)); 1061 1062 int64_t res; 1063 bool overflow = false; 1064 if (!is_integer(t) || is_uinteger(t)) { 1065 uint64_t u_res = fold_unsigned_integer(tn->tn_op, 1066 (uint64_t)l, (uint64_t)r, mask, &overflow); 1067 if (u_res > mask) 1068 overflow = true; 1069 res = (int64_t)u_res; 1070 if (overflow && hflag) { 1071 char buf[128]; 1072 if (is_binary(tn)) { 1073 snprintf(buf, sizeof(buf), "%ju %s %ju", 1074 (uintmax_t)l, op_name(tn->tn_op), 1075 (uintmax_t)r); 1076 } else { 1077 snprintf(buf, sizeof(buf), "%s%ju", 1078 op_name(tn->tn_op), (uintmax_t)l); 1079 } 1080 /* '%s' overflows '%s' */ 1081 warning(141, buf, type_name(tn->tn_type)); 1082 } 1083 } else { 1084 int64_t max_value = (int64_t)(mask >> 1); 1085 int64_t min_value = -max_value - 1; 1086 res = fold_signed_integer(tn->tn_op, 1087 l, r, min_value, max_value, &overflow); 1088 if (res < min_value || res > max_value) 1089 overflow = true; 1090 if (overflow && hflag) { 1091 char buf[128]; 1092 if (is_binary(tn)) { 1093 snprintf(buf, sizeof(buf), "%jd %s %jd", 1094 (intmax_t)l, op_name(tn->tn_op), 1095 (intmax_t)r); 1096 } else if (tn->tn_op == UMINUS && l < 0) { 1097 snprintf(buf, sizeof(buf), "-(%jd)", 1098 (intmax_t)l); 1099 } else { 1100 snprintf(buf, sizeof(buf), "%s%jd", 1101 op_name(tn->tn_op), (intmax_t)l); 1102 } 1103 /* '%s' overflows '%s' */ 1104 warning(141, buf, type_name(tn->tn_type)); 1105 } 1106 } 1107 1108 val_t *v = xcalloc(1, sizeof(*v)); 1109 v->v_tspec = tn->tn_type->t_tspec; 1110 v->u.integer = convert_integer(res, t, size_in_bits(t)); 1111 1112 tnode_t *cn = build_constant(tn->tn_type, v); 1113 if (tn->u.ops.left->tn_system_dependent) 1114 cn->tn_system_dependent = true; 1115 if (is_binary(tn) && tn->u.ops.right->tn_system_dependent) 1116 cn->tn_system_dependent = true; 1117 1118 return cn; 1119 } 1120 1121 static tnode_t * 1122 build_struct_access(op_t op, bool sys, tnode_t *ln, tnode_t *rn) 1123 { 1124 1125 lint_assert(rn->tn_op == NAME); 1126 lint_assert(is_member(rn->u.sym)); 1127 1128 bool lvalue = op == ARROW || ln->tn_lvalue; 1129 1130 if (op == POINT) 1131 ln = build_address(sys, ln, true); 1132 else if (ln->tn_type->t_tspec != PTR) { 1133 lint_assert(!allow_c90); 1134 lint_assert(is_integer(ln->tn_type->t_tspec)); 1135 ln = convert(NOOP, 0, expr_derive_type(gettyp(VOID), PTR), ln); 1136 } 1137 1138 tnode_t *ctn = build_integer_constant(PTRDIFF_TSPEC, 1139 rn->u.sym->u.s_member.sm_offset_in_bits / CHAR_SIZE); 1140 1141 type_t *ptr_tp = expr_derive_type(rn->tn_type, PTR); 1142 tnode_t *ntn = build_op(PLUS, sys, ptr_tp, ln, ctn); 1143 if (ln->tn_op == CON) 1144 ntn = fold_constant_integer(ntn); 1145 1146 op_t nop = rn->tn_type->t_bitfield ? FSEL : INDIR; 1147 ntn = build_op(nop, sys, ntn->tn_type->t_subt, ntn, NULL); 1148 if (!lvalue) 1149 ntn->tn_lvalue = false; 1150 1151 return ntn; 1152 } 1153 1154 /* 1155 * Get the size in bytes of type tp->t_subt, as a constant expression of type 1156 * ptrdiff_t as seen from the target platform. 1157 */ 1158 static tnode_t * 1159 subt_size_in_bytes(type_t *tp) 1160 { 1161 1162 lint_assert(tp->t_tspec == PTR); 1163 tp = tp->t_subt; 1164 1165 int elem = 1; 1166 while (tp->t_tspec == ARRAY) { 1167 elem *= tp->u.dimension; 1168 tp = tp->t_subt; 1169 } 1170 1171 int elsz_in_bits = 0; 1172 switch (tp->t_tspec) { 1173 case FUNC: 1174 /* pointer to function is not allowed here */ 1175 error(110); 1176 break; 1177 case VOID: 1178 /* cannot do pointer arithmetic on operand of unknown size */ 1179 gnuism(136); 1180 break; 1181 case STRUCT: 1182 case UNION: 1183 if ((elsz_in_bits = (int)tp->u.sou->sou_size_in_bits) == 0) 1184 /* cannot do pointer arithmetic on operand of ... */ 1185 error(136); 1186 break; 1187 case ENUM: 1188 if (is_incomplete(tp)) 1189 /* cannot do pointer arithmetic on operand of ... */ 1190 warning(136); 1191 /* FALLTHROUGH */ 1192 default: 1193 if ((elsz_in_bits = size_in_bits(tp->t_tspec)) == 0) 1194 /* cannot do pointer arithmetic on operand of ... */ 1195 error(136); 1196 else 1197 lint_assert(elsz_in_bits != -1); 1198 break; 1199 } 1200 1201 if (elem == 0 && elsz_in_bits != 0) 1202 /* cannot do pointer arithmetic on operand of unknown size */ 1203 error(136); 1204 1205 if (elsz_in_bits == 0) 1206 elsz_in_bits = CHAR_SIZE; 1207 1208 return build_integer_constant(PTRDIFF_TSPEC, 1209 (int64_t)(elem * elsz_in_bits / CHAR_SIZE)); 1210 } 1211 1212 static tnode_t * 1213 build_prepost_incdec(op_t op, bool sys, tnode_t *ln) 1214 { 1215 1216 lint_assert(ln != NULL); 1217 tnode_t *cn = ln->tn_type->t_tspec == PTR 1218 ? subt_size_in_bytes(ln->tn_type) 1219 : build_integer_constant(INT, 1); 1220 return build_op(op, sys, ln->tn_type, ln, cn); 1221 } 1222 1223 static void 1224 check_enum_array_index(const tnode_t *ln, const tnode_t *rn) 1225 { 1226 1227 if (ln->tn_op != ADDR || ln->u.ops.left->tn_op != NAME) 1228 return; 1229 1230 const type_t *ltp = ln->u.ops.left->tn_type; 1231 if (ltp->t_tspec != ARRAY || ltp->t_incomplete_array) 1232 return; 1233 1234 if (rn->tn_op != CVT || !rn->tn_type->t_is_enum) 1235 return; 1236 if (rn->u.ops.left->tn_op != LOAD) 1237 return; 1238 1239 const type_t *rtp = rn->u.ops.left->tn_type; 1240 const sym_t *ec = rtp->u.enumer->en_first_enumerator; 1241 const sym_t *max_ec = ec; 1242 lint_assert(ec != NULL); 1243 for (ec = ec->s_next; ec != NULL; ec = ec->s_next) 1244 if (ec->u.s_enum_constant > max_ec->u.s_enum_constant) 1245 max_ec = ec; 1246 1247 int64_t max_enum_value = max_ec->u.s_enum_constant; 1248 lint_assert(INT_MIN <= max_enum_value && max_enum_value <= INT_MAX); 1249 1250 int max_array_index = ltp->u.dimension - 1; 1251 if (max_enum_value == max_array_index) 1252 return; 1253 1254 if (max_enum_value == max_array_index + 1 && 1255 (strstr(max_ec->s_name, "MAX") != NULL || 1256 strstr(max_ec->s_name, "max") != NULL || 1257 strstr(max_ec->s_name, "NUM") != NULL || 1258 strstr(max_ec->s_name, "num") != NULL || 1259 strncmp(max_ec->s_name, "N_", 2) == 0)) 1260 return; 1261 1262 /* maximum value %d for '%s' of type '%s' does not match maximum array index %d */ 1263 warning(348, (int)max_enum_value, max_ec->s_name, type_name(rtp), 1264 max_array_index); 1265 print_previous_declaration(max_ec); 1266 } 1267 1268 static tnode_t * 1269 build_plus_minus(op_t op, bool sys, tnode_t *ln, tnode_t *rn) 1270 { 1271 1272 if (rn->tn_type->t_tspec == PTR && is_integer(ln->tn_type->t_tspec)) { 1273 tnode_t *tmp = ln; 1274 ln = rn; 1275 rn = tmp; 1276 /* pointer addition has integer on the left-hand side */ 1277 query_message(5); 1278 } 1279 1280 /* pointer +- integer */ 1281 tspec_t lt = ln->tn_type->t_tspec; 1282 tspec_t rt = rn->tn_type->t_tspec; 1283 if (lt == PTR && rt != PTR) { 1284 lint_assert(is_integer(rt)); 1285 1286 check_ctype_macro_invocation(ln, rn); 1287 check_enum_array_index(ln, rn); 1288 1289 tnode_t *elsz = subt_size_in_bytes(ln->tn_type); 1290 tspec_t szt = elsz->tn_type->t_tspec; 1291 if (rt != szt && rt != unsigned_type(szt)) 1292 rn = convert(NOOP, 0, elsz->tn_type, rn); 1293 1294 tnode_t *prod = build_op(MULT, sys, rn->tn_type, rn, elsz); 1295 if (rn->tn_op == CON) 1296 prod = fold_constant_integer(prod); 1297 1298 return build_op(op, sys, ln->tn_type, ln, prod); 1299 } 1300 1301 /* pointer - pointer */ 1302 if (rt == PTR) { 1303 lint_assert(lt == PTR); 1304 lint_assert(op == MINUS); 1305 1306 type_t *ptrdiff = gettyp(PTRDIFF_TSPEC); 1307 tnode_t *raw_diff = build_op(op, sys, ptrdiff, ln, rn); 1308 if (ln->tn_op == CON && rn->tn_op == CON) 1309 raw_diff = fold_constant_integer(raw_diff); 1310 1311 tnode_t *elsz = subt_size_in_bytes(ln->tn_type); 1312 balance(NOOP, &raw_diff, &elsz); 1313 1314 return build_op(DIV, sys, ptrdiff, raw_diff, elsz); 1315 } 1316 1317 return build_op(op, sys, ln->tn_type, ln, rn); 1318 } 1319 1320 static tnode_t * 1321 build_bit_shift(op_t op, bool sys, tnode_t *ln, tnode_t *rn) 1322 { 1323 1324 if (!allow_c90 && rn->tn_type->t_tspec != INT) 1325 // XXX: C1978 7.5 says: "Both [operators] perform the usual 1326 // arithmetic conversions on their operands." 1327 // TODO: Add a test to exercise this part of the code. 1328 rn = convert(NOOP, 0, gettyp(INT), rn); 1329 return build_op(op, sys, ln->tn_type, ln, rn); 1330 } 1331 1332 static bool 1333 is_null_pointer(const tnode_t *tn) 1334 { 1335 tspec_t t = tn->tn_type->t_tspec; 1336 1337 // TODO: Investigate how other pointers are stored, in particular, 1338 // whether a pointer constant can have a non-zero value. 1339 // If not, simplify the code below. 1340 return ((t == PTR && tn->tn_type->t_subt->t_tspec == VOID) 1341 || is_integer(t)) 1342 && (tn->tn_op == CON && tn->u.value.u.integer == 0); 1343 } 1344 1345 /* Return a type based on tp1, with added qualifiers from tp2. */ 1346 static type_t * 1347 merge_qualifiers(type_t *tp1, const type_t *tp2) 1348 { 1349 1350 lint_assert(tp1->t_tspec == PTR); 1351 lint_assert(tp2->t_tspec == PTR); 1352 1353 bool c1 = tp1->t_subt->t_const; 1354 bool c2 = tp2->t_subt->t_const; 1355 bool v1 = tp1->t_subt->t_volatile; 1356 bool v2 = tp2->t_subt->t_volatile; 1357 1358 if (c1 == (c1 | c2) && v1 == (v1 | v2)) 1359 return tp1; 1360 1361 type_t *nstp = expr_dup_type(tp1->t_subt); 1362 nstp->t_const |= c2; 1363 nstp->t_volatile |= v2; 1364 1365 type_t *ntp = expr_dup_type(tp1); 1366 ntp->t_subt = nstp; 1367 return ntp; 1368 } 1369 1370 /* See C99 6.5.15 "Conditional operator". */ 1371 static tnode_t * 1372 build_colon(bool sys, tnode_t *ln, tnode_t *rn) 1373 { 1374 tspec_t lt = ln->tn_type->t_tspec; 1375 tspec_t rt = rn->tn_type->t_tspec; 1376 1377 type_t *tp; 1378 if (is_arithmetic(lt) && is_arithmetic(rt)) 1379 /* The operands were already balanced in build_binary. */ 1380 tp = ln->tn_type; 1381 else if (lt == BOOL && rt == BOOL) 1382 tp = ln->tn_type; 1383 else if (lt == VOID || rt == VOID) 1384 tp = gettyp(VOID); 1385 else if (is_struct_or_union(lt)) { 1386 lint_assert(is_struct_or_union(rt)); 1387 lint_assert(ln->tn_type->u.sou == rn->tn_type->u.sou); 1388 if (is_incomplete(ln->tn_type)) { 1389 /* unknown operand size, op '%s' */ 1390 error(138, op_name(COLON)); 1391 return NULL; 1392 } 1393 tp = ln->tn_type; 1394 } else if (lt == PTR && is_integer(rt)) { 1395 if (rt != PTRDIFF_TSPEC) 1396 rn = convert(NOOP, 0, gettyp(PTRDIFF_TSPEC), rn); 1397 tp = ln->tn_type; 1398 } else if (rt == PTR && is_integer(lt)) { 1399 if (lt != PTRDIFF_TSPEC) 1400 ln = convert(NOOP, 0, gettyp(PTRDIFF_TSPEC), ln); 1401 tp = rn->tn_type; 1402 } else if (lt == PTR && is_null_pointer(rn)) 1403 tp = merge_qualifiers(ln->tn_type, rn->tn_type); 1404 else if (rt == PTR && is_null_pointer(ln)) 1405 tp = merge_qualifiers(rn->tn_type, ln->tn_type); 1406 else if (lt == PTR && ln->tn_type->t_subt->t_tspec == VOID) 1407 tp = merge_qualifiers(ln->tn_type, rn->tn_type); 1408 else if (rt == PTR && rn->tn_type->t_subt->t_tspec == VOID) 1409 tp = merge_qualifiers(rn->tn_type, ln->tn_type); 1410 else { 1411 /* 1412 * XXX For now we simply take the left type. This is probably 1413 * wrong, if one type contains a function prototype and the 1414 * other one, at the same place, only an old-style declaration. 1415 */ 1416 tp = merge_qualifiers(ln->tn_type, rn->tn_type); 1417 } 1418 1419 return build_op(COLON, sys, tp, ln, rn); 1420 } 1421 1422 /* TODO: check for varargs */ 1423 static bool 1424 is_cast_redundant(const tnode_t *tn) 1425 { 1426 const type_t *ntp = tn->tn_type, *otp = tn->u.ops.left->tn_type; 1427 tspec_t nt = ntp->t_tspec, ot = otp->t_tspec; 1428 1429 if (nt == BOOL || ot == BOOL) 1430 return nt == BOOL && ot == BOOL; 1431 1432 if (is_integer(nt) && is_integer(ot)) { 1433 unsigned int nw = width_in_bits(ntp), ow = width_in_bits(otp); 1434 if (is_uinteger(nt) == is_uinteger(ot)) 1435 return nw >= ow; 1436 return is_uinteger(ot) && nw > ow; 1437 } 1438 1439 if (is_complex(nt) || is_complex(ot)) 1440 return is_complex(nt) && is_complex(ot) && 1441 size_in_bits(nt) >= size_in_bits(ot); 1442 1443 if (is_floating(nt) && is_floating(ot)) 1444 return size_in_bits(nt) >= size_in_bits(ot); 1445 1446 if (nt == PTR && ot == PTR) { 1447 if (!ntp->t_subt->t_const && otp->t_subt->t_const) 1448 return false; 1449 if (!ntp->t_subt->t_volatile && otp->t_subt->t_volatile) 1450 return false; 1451 1452 if (ntp->t_subt->t_tspec == VOID || 1453 otp->t_subt->t_tspec == VOID || 1454 types_compatible(ntp->t_subt, otp->t_subt, 1455 false, false, NULL)) 1456 return true; 1457 } 1458 1459 return false; 1460 } 1461 1462 static bool 1463 is_assignment(op_t op) 1464 { 1465 1466 return op == ASSIGN || 1467 op == MULASS || 1468 op == DIVASS || 1469 op == MODASS || 1470 op == ADDASS || 1471 op == SUBASS || 1472 op == SHLASS || 1473 op == SHRASS || 1474 op == ANDASS || 1475 op == XORASS || 1476 op == ORASS || 1477 op == RETURN || 1478 op == INIT; 1479 } 1480 1481 static tnode_t * 1482 build_assignment(op_t op, bool sys, tnode_t *ln, tnode_t *rn) 1483 { 1484 1485 tspec_t lt = ln->tn_type->t_tspec; 1486 tspec_t rt = rn->tn_type->t_tspec; 1487 1488 if (any_query_enabled && is_assignment(rn->tn_op)) { 1489 /* chained assignment with '%s' and '%s' */ 1490 query_message(10, op_name(op), op_name(rn->tn_op)); 1491 } 1492 1493 if ((op == ADDASS || op == SUBASS) && lt == PTR) { 1494 lint_assert(is_integer(rt)); 1495 tnode_t *ctn = subt_size_in_bytes(ln->tn_type); 1496 if (rn->tn_type->t_tspec != ctn->tn_type->t_tspec) 1497 rn = convert(NOOP, 0, ctn->tn_type, rn); 1498 rn = build_op(MULT, sys, rn->tn_type, rn, ctn); 1499 if (rn->u.ops.left->tn_op == CON) 1500 rn = fold_constant_integer(rn); 1501 } 1502 1503 if ((op == ASSIGN || op == RETURN || op == INIT) && 1504 (lt == STRUCT || rt == STRUCT)) { 1505 lint_assert(lt == rt); 1506 lint_assert(ln->tn_type->u.sou == rn->tn_type->u.sou); 1507 if (is_incomplete(ln->tn_type)) { 1508 if (op == RETURN) 1509 /* cannot return incomplete type */ 1510 error(212); 1511 else 1512 /* unknown operand size, op '%s' */ 1513 error(138, op_name(op)); 1514 return NULL; 1515 } 1516 } 1517 1518 if (op == SHLASS && hflag && allow_trad && allow_c90 1519 && portable_rank_cmp(lt, rt) < 0) 1520 /* semantics of '%s' change in C90; ... */ 1521 warning(118, "<<="); 1522 1523 if (op != SHLASS && op != SHRASS 1524 && (op == ASSIGN || lt != PTR) 1525 && (lt != rt || (ln->tn_type->t_bitfield && rn->tn_op == CON))) { 1526 rn = convert(op, 0, ln->tn_type, rn); 1527 rt = lt; 1528 } 1529 1530 if (is_query_enabled[20] 1531 && lt == PTR && ln->tn_type->t_subt->t_tspec != VOID 1532 && rt == PTR && rn->tn_type->t_subt->t_tspec == VOID 1533 && !is_null_pointer(rn)) 1534 /* implicit narrowing conversion from void ... */ 1535 query_message(20, type_name(ln->tn_type)); 1536 1537 if (any_query_enabled && rn->tn_op == CVT && rn->tn_cast && 1538 types_compatible(ln->tn_type, rn->tn_type, false, false, NULL) && 1539 is_cast_redundant(rn)) { 1540 /* redundant cast from '%s' to '%s' before assignment */ 1541 query_message(7, type_name(rn->u.ops.left->tn_type), 1542 type_name(rn->tn_type)); 1543 } 1544 1545 return build_op(op, sys, ln->tn_type, ln, rn); 1546 } 1547 1548 static tnode_t * 1549 build_real_imag(op_t op, bool sys, tnode_t *ln) 1550 { 1551 1552 lint_assert(ln != NULL); 1553 if (ln->tn_op == NAME) { 1554 /* 1555 * This may be too much, but it avoids wrong warnings. See 1556 * d_c99_complex_split.c. 1557 */ 1558 mark_as_used(ln->u.sym, false, false); 1559 mark_as_set(ln->u.sym); 1560 } 1561 1562 tspec_t t; 1563 switch (ln->tn_type->t_tspec) { 1564 case LCOMPLEX: 1565 t = LDOUBLE; 1566 break; 1567 case DCOMPLEX: 1568 t = DOUBLE; 1569 break; 1570 case FCOMPLEX: 1571 t = FLOAT; 1572 break; 1573 default: 1574 /* '__%s__' is illegal for type '%s' */ 1575 error(276, op == REAL ? "real" : "imag", 1576 type_name(ln->tn_type)); 1577 return NULL; 1578 } 1579 1580 tnode_t *ntn = build_op(op, sys, gettyp(t), ln, NULL); 1581 ntn->tn_lvalue = true; 1582 return ntn; 1583 } 1584 1585 static bool 1586 is_confusing_precedence(op_t op, op_t lop, bool lparen, op_t rop, bool rparen) 1587 { 1588 1589 if (op == SHL || op == SHR) { 1590 if (!lparen && (lop == PLUS || lop == MINUS)) 1591 return true; 1592 if (!rparen && (rop == PLUS || rop == MINUS)) 1593 return true; 1594 return false; 1595 } 1596 1597 if (op == LOGOR) { 1598 if (!lparen && lop == LOGAND) 1599 return true; 1600 if (!rparen && rop == LOGAND) 1601 return true; 1602 return false; 1603 } 1604 1605 lint_assert(op == BITAND || op == BITXOR || op == BITOR); 1606 if (!lparen && lop != op) { 1607 if (lop == PLUS || lop == MINUS) 1608 return true; 1609 if (lop == BITAND || lop == BITXOR) 1610 return true; 1611 } 1612 if (!rparen && rop != op) { 1613 if (rop == PLUS || rop == MINUS) 1614 return true; 1615 if (rop == BITAND || rop == BITXOR) 1616 return true; 1617 } 1618 return false; 1619 } 1620 1621 /* 1622 * Print a warning if the given node has operands which should be 1623 * parenthesized. 1624 * 1625 * XXX Does not work if an operand is a constant expression. Constant 1626 * expressions are already folded. 1627 */ 1628 static void 1629 check_precedence_confusion(tnode_t *tn) 1630 { 1631 tnode_t *ln, *rn; 1632 1633 if (!hflag) 1634 return; 1635 1636 debug_node(tn); 1637 1638 lint_assert(is_binary(tn)); 1639 for (ln = tn->u.ops.left; ln->tn_op == CVT; ln = ln->u.ops.left) 1640 continue; 1641 for (rn = tn->u.ops.right; rn->tn_op == CVT; rn = rn->u.ops.left) 1642 continue; 1643 1644 if (is_confusing_precedence(tn->tn_op, 1645 ln->tn_op, ln->tn_parenthesized, 1646 rn->tn_op, rn->tn_parenthesized)) { 1647 /* precedence confusion possible: parenthesize! */ 1648 warning(169); 1649 } 1650 } 1651 1652 static tnode_t * 1653 fold_constant_compare_zero(tnode_t *tn) 1654 { 1655 1656 val_t *v = xcalloc(1, sizeof(*v)); 1657 v->v_tspec = tn->tn_type->t_tspec; 1658 lint_assert(v->v_tspec == INT || (Tflag && v->v_tspec == BOOL)); 1659 1660 lint_assert(has_operands(tn)); 1661 bool l = constant_is_nonzero(tn->u.ops.left); 1662 bool r = is_binary(tn) && constant_is_nonzero(tn->u.ops.right); 1663 1664 switch (tn->tn_op) { 1665 case NOT: 1666 if (hflag && !suppress_constcond) 1667 /* constant operand to '!' */ 1668 warning(239); 1669 v->u.integer = !l ? 1 : 0; 1670 break; 1671 case LOGAND: 1672 v->u.integer = l && r ? 1 : 0; 1673 break; 1674 case LOGOR: 1675 v->u.integer = l || r ? 1 : 0; 1676 break; 1677 default: 1678 lint_assert(/*CONSTCOND*/false); 1679 } 1680 1681 return build_constant(tn->tn_type, v); 1682 } 1683 1684 static long double 1685 floating_error_value(tspec_t t, long double lv) 1686 { 1687 if (t == FLOAT) 1688 return lv < 0 ? -FLT_MAX : FLT_MAX; 1689 if (t == DOUBLE) 1690 return lv < 0 ? -DBL_MAX : DBL_MAX; 1691 /* 1692 * When NetBSD is cross-built in MKLINT=yes mode on x86_64 for sparc64, 1693 * tools/lint checks this code while building usr.bin/xlint. In that 1694 * situation, lint uses the preprocessor for sparc64, in which the type 1695 * 'long double' is IEEE-754-binary128, affecting the macro LDBL_MAX 1696 * below. The type 'long double', as well as the strtold 1697 * implementation, comes from the host platform x86_64 though, where 1698 * 'long double' consumes 128 bits as well but only uses 80 of them. 1699 * The exponent range of the two 'long double' types is the same, but 1700 * the maximum finite value differs due to the extended precision on 1701 * sparc64. 1702 * 1703 * To properly handle the data types of the target platform, lint would 1704 * have to implement the floating-point types in a platform-independent 1705 * way, which is not worth the effort, given how few programs 1706 * practically use 'long double'. 1707 */ 1708 /* LINTED 248: floating-point constant out of range */ 1709 long double max = LDBL_MAX; 1710 return lv < 0 ? -max : max; 1711 } 1712 1713 static bool 1714 is_floating_overflow(tspec_t t, long double val) 1715 { 1716 if (fpe != 0 || isfinite(val) == 0) 1717 return true; 1718 if (t == FLOAT && (val > FLT_MAX || val < -FLT_MAX)) 1719 return true; 1720 if (t == DOUBLE && (val > DBL_MAX || val < -DBL_MAX)) 1721 return true; 1722 return false; 1723 } 1724 1725 static tnode_t * 1726 fold_constant_floating(tnode_t *tn) 1727 { 1728 1729 fpe = 0; 1730 1731 tspec_t t = tn->tn_type->t_tspec; 1732 1733 val_t *v = xcalloc(1, sizeof(*v)); 1734 v->v_tspec = t; 1735 1736 lint_assert(is_floating(t)); 1737 lint_assert(has_operands(tn)); 1738 lint_assert(t == tn->u.ops.left->tn_type->t_tspec); 1739 lint_assert(!is_binary(tn) || t == tn->u.ops.right->tn_type->t_tspec); 1740 1741 long double lv = tn->u.ops.left->u.value.u.floating; 1742 long double rv = is_binary(tn) ? tn->u.ops.right->u.value.u.floating 1743 : 0.0; 1744 1745 switch (tn->tn_op) { 1746 case UPLUS: 1747 v->u.floating = lv; 1748 break; 1749 case UMINUS: 1750 v->u.floating = -lv; 1751 break; 1752 case MULT: 1753 v->u.floating = lv * rv; 1754 break; 1755 case DIV: 1756 if (rv == 0.0) { 1757 /* division by 0 */ 1758 error(139); 1759 v->u.floating = floating_error_value(t, lv); 1760 } else { 1761 v->u.floating = lv / rv; 1762 } 1763 break; 1764 case PLUS: 1765 v->u.floating = lv + rv; 1766 break; 1767 case MINUS: 1768 v->u.floating = lv - rv; 1769 break; 1770 case LT: 1771 v->u.integer = lv < rv ? 1 : 0; 1772 break; 1773 case LE: 1774 v->u.integer = lv <= rv ? 1 : 0; 1775 break; 1776 case GE: 1777 v->u.integer = lv >= rv ? 1 : 0; 1778 break; 1779 case GT: 1780 v->u.integer = lv > rv ? 1 : 0; 1781 break; 1782 case EQ: 1783 v->u.integer = lv == rv ? 1 : 0; 1784 break; 1785 case NE: 1786 v->u.integer = lv != rv ? 1 : 0; 1787 break; 1788 default: 1789 lint_assert(/*CONSTCOND*/false); 1790 } 1791 1792 // XXX: Must not access u.floating after setting u.integer. 1793 lint_assert(fpe != 0 || isnan(v->u.floating) == 0); 1794 if (is_complex(v->v_tspec)) { 1795 /* 1796 * Don't warn, as lint doesn't model the imaginary part of 1797 * complex numbers. 1798 */ 1799 fpe = 0; 1800 } else if (is_floating_overflow(t, v->u.floating)) { 1801 /* operator '%s' produces floating point overflow */ 1802 warning(142, op_name(tn->tn_op)); 1803 v->u.floating = floating_error_value(t, v->u.floating); 1804 fpe = 0; 1805 } 1806 1807 return build_constant(tn->tn_type, v); 1808 } 1809 1810 static void 1811 use(const tnode_t *tn) 1812 { 1813 if (tn == NULL) 1814 return; 1815 switch (tn->tn_op) { 1816 case NAME: 1817 mark_as_used(tn->u.sym, false /* XXX */, false /* XXX */); 1818 break; 1819 case CON: 1820 case STRING: 1821 break; 1822 case CALL:; 1823 const function_call *call = tn->u.call; 1824 for (size_t i = 0, n = call->args_len; i < n; i++) 1825 use(call->args[i]); 1826 break; 1827 default: 1828 lint_assert(has_operands(tn)); 1829 use(tn->u.ops.left); 1830 if (is_binary(tn)) 1831 use(tn->u.ops.right); 1832 } 1833 } 1834 1835 /* 1836 * Create a tree node for a binary operator and its two operands. Also called 1837 * for unary operators; in that case rn is NULL. 1838 * 1839 * Function calls, sizeof and casts are handled elsewhere. 1840 */ 1841 tnode_t * 1842 build_binary(tnode_t *ln, op_t op, bool sys, tnode_t *rn) 1843 { 1844 const mod_t *mp = &modtab[op]; 1845 1846 /* If there was an error in one of the operands, return. */ 1847 if (ln == NULL || (mp->m_binary && rn == NULL)) 1848 return NULL; 1849 1850 if (mp->m_value_context || mp->m_compares_with_zero) 1851 ln = cconv(ln); 1852 if (mp->m_binary && op != ARROW && op != POINT) 1853 rn = cconv(rn); 1854 1855 if (mp->m_comparison) 1856 check_integer_comparison(op, ln, rn); 1857 1858 if (mp->m_value_context || mp->m_compares_with_zero) 1859 ln = promote(op, false, ln); 1860 if (mp->m_binary && op != ARROW && op != POINT && 1861 op != ASSIGN && op != RETURN && op != INIT) 1862 rn = promote(op, false, rn); 1863 1864 if (mp->m_warn_if_left_unsigned_in_c90 && 1865 ln->tn_op == CON && ln->u.value.v_unsigned_since_c90) { 1866 /* C90 treats constant as unsigned, op '%s' */ 1867 warning(218, op_name(op)); 1868 ln->u.value.v_unsigned_since_c90 = false; 1869 } 1870 if (mp->m_warn_if_right_unsigned_in_c90 && 1871 rn->tn_op == CON && rn->u.value.v_unsigned_since_c90) { 1872 /* C90 treats constant as unsigned, op '%s' */ 1873 warning(218, op_name(op)); 1874 rn->u.value.v_unsigned_since_c90 = false; 1875 } 1876 1877 if (mp->m_balance_operands || (!allow_c90 && (op == SHL || op == SHR))) 1878 balance(op, &ln, &rn); 1879 1880 if (!typeok(op, 0, ln, rn)) 1881 return NULL; 1882 1883 tnode_t *ntn; 1884 switch (op) { 1885 case POINT: 1886 case ARROW: 1887 ntn = build_struct_access(op, sys, ln, rn); 1888 break; 1889 case NOT: 1890 if (ln->tn_op == ASSIGN && ln->u.ops.right->tn_op == CON) { 1891 /* constant assignment of type '%s' in operand ... */ 1892 warning(382, type_name(ln->tn_type), 1893 is_nonzero_val(&ln->u.ops.right->u.value) 1894 ? "true" : "false"); 1895 } 1896 ntn = build_op(op, sys, gettyp(Tflag ? BOOL : INT), ln, NULL); 1897 break; 1898 case INCAFT: 1899 case DECAFT: 1900 case INCBEF: 1901 case DECBEF: 1902 ntn = build_prepost_incdec(op, sys, ln); 1903 break; 1904 case ADDR: 1905 ntn = build_address(sys, ln, false); 1906 break; 1907 case INDIR: 1908 ntn = build_op(INDIR, sys, ln->tn_type->t_subt, ln, NULL); 1909 break; 1910 case PLUS: 1911 case MINUS: 1912 ntn = build_plus_minus(op, sys, ln, rn); 1913 break; 1914 case SHL: 1915 case SHR: 1916 ntn = build_bit_shift(op, sys, ln, rn); 1917 break; 1918 case COLON: 1919 ntn = build_colon(sys, ln, rn); 1920 break; 1921 case ASSIGN: 1922 case MULASS: 1923 case DIVASS: 1924 case MODASS: 1925 case ADDASS: 1926 case SUBASS: 1927 case SHLASS: 1928 case SHRASS: 1929 case ANDASS: 1930 case XORASS: 1931 case ORASS: 1932 case RETURN: 1933 case INIT: 1934 ntn = build_assignment(op, sys, ln, rn); 1935 break; 1936 case COMMA: 1937 if (any_query_enabled) { 1938 /* comma operator with types '%s' and '%s' */ 1939 query_message(12, 1940 type_name(ln->tn_type), type_name(rn->tn_type)); 1941 } 1942 /* FALLTHROUGH */ 1943 case QUEST: 1944 ntn = build_op(op, sys, rn->tn_type, ln, rn); 1945 break; 1946 case REAL: 1947 case IMAG: 1948 ntn = build_real_imag(op, sys, ln); 1949 break; 1950 default: 1951 lint_assert(mp->m_binary == (rn != NULL)); 1952 type_t *rettp = mp->m_returns_bool 1953 ? gettyp(Tflag ? BOOL : INT) : ln->tn_type; 1954 ntn = build_op(op, sys, rettp, ln, rn); 1955 break; 1956 } 1957 1958 if (ntn == NULL) 1959 return NULL; 1960 1961 if (mp->m_possible_precedence_confusion) 1962 check_precedence_confusion(ntn); 1963 1964 if (hflag && !suppress_constcond && 1965 mp->m_compares_with_zero && 1966 (ln->tn_op == CON || 1967 (mp->m_binary && op != QUEST && rn->tn_op == CON)) && 1968 /* XXX: rn->tn_system_dependent should be checked as well */ 1969 !ln->tn_system_dependent) 1970 /* constant in conditional context */ 1971 warning(161); 1972 1973 if (mp->m_fold_constant_operands && ln->tn_op == CON) { 1974 if (!mp->m_binary || rn->tn_op == CON) { 1975 if (mp->m_compares_with_zero) 1976 ntn = fold_constant_compare_zero(ntn); 1977 else if (is_floating(ntn->tn_type->t_tspec)) 1978 ntn = fold_constant_floating(ntn); 1979 else 1980 ntn = fold_constant_integer(ntn); 1981 } else if (op == QUEST) { 1982 lint_assert(has_operands(rn)); 1983 use(ln->u.value.u.integer != 0 1984 ? rn->u.ops.right : rn->u.ops.left); 1985 ntn = ln->u.value.u.integer != 0 1986 ? rn->u.ops.left : rn->u.ops.right; 1987 } 1988 } 1989 1990 return ntn; 1991 } 1992 1993 tnode_t * 1994 build_unary(op_t op, bool sys, tnode_t *tn) 1995 { 1996 return build_binary(tn, op, sys, NULL); 1997 } 1998 1999 static bool 2000 are_members_compatible(const sym_t *a, const sym_t *b) 2001 { 2002 if (a->u.s_member.sm_offset_in_bits != b->u.s_member.sm_offset_in_bits) 2003 return false; 2004 2005 const type_t *atp = a->s_type; 2006 const type_t *btp = b->s_type; 2007 bool w = false; 2008 if (!types_compatible(atp, btp, false, false, &w) && !w) 2009 return false; 2010 if (a->s_bitfield != b->s_bitfield) 2011 return false; 2012 if (a->s_bitfield) { 2013 if (atp->t_bit_field_width != btp->t_bit_field_width) 2014 return false; 2015 if (atp->t_bit_field_offset != btp->t_bit_field_offset) 2016 return false; 2017 } 2018 return true; 2019 } 2020 2021 /* 2022 * Return whether all struct/union members with the same name have the same 2023 * type and offset. 2024 */ 2025 static bool 2026 all_members_compatible(const sym_t *msym) 2027 { 2028 for (const sym_t *csym = msym; 2029 csym != NULL; csym = csym->s_symtab_next) { 2030 if (!is_member(csym)) 2031 continue; 2032 if (strcmp(msym->s_name, csym->s_name) != 0) 2033 continue; 2034 2035 for (const sym_t *sym = csym->s_symtab_next; 2036 sym != NULL; sym = sym->s_symtab_next) { 2037 if (is_member(sym) 2038 && strcmp(csym->s_name, sym->s_name) == 0 2039 && !are_members_compatible(csym, sym)) 2040 return false; 2041 } 2042 } 2043 return true; 2044 } 2045 2046 sym_t * 2047 find_member(const struct_or_union *sou, const char *name) 2048 { 2049 for (sym_t *mem = sou->sou_first_member; 2050 mem != NULL; mem = mem->s_next) { 2051 lint_assert(is_member(mem)); 2052 lint_assert(mem->u.s_member.sm_containing_type == sou); 2053 if (strcmp(mem->s_name, name) == 0) 2054 return mem; 2055 } 2056 2057 for (sym_t *mem = sou->sou_first_member; 2058 mem != NULL; mem = mem->s_next) { 2059 if (is_struct_or_union(mem->s_type->t_tspec) 2060 && mem->s_name == unnamed) { 2061 sym_t *nested_mem = 2062 find_member(mem->s_type->u.sou, name); 2063 if (nested_mem != NULL) 2064 return nested_mem; 2065 } 2066 } 2067 return NULL; 2068 } 2069 2070 /* 2071 * Remove the member if it was unknown until now, which means 2072 * that no defined struct or union has a member with the same name. 2073 */ 2074 static void 2075 remove_unknown_member(tnode_t *tn, sym_t *msym) 2076 { 2077 /* type '%s' does not have member '%s' */ 2078 error(101, type_name(tn->tn_type), msym->s_name); 2079 symtab_remove_forever(msym); 2080 msym->s_kind = SK_MEMBER; 2081 msym->s_scl = STRUCT_MEMBER; 2082 2083 struct_or_union *sou = expr_zero_alloc(sizeof(*sou), 2084 "struct_or_union"); 2085 sou->sou_tag = expr_zero_alloc(sizeof(*sou->sou_tag), "sym"); 2086 sou->sou_tag->s_name = unnamed; 2087 2088 msym->u.s_member.sm_containing_type = sou; 2089 /* 2090 * The member sm_offset_in_bits is not needed here since this symbol 2091 * can only be used for error reporting. 2092 */ 2093 } 2094 2095 /* 2096 * Returns a symbol which has the same name as 'msym' and is a member of the 2097 * struct or union specified by 'tn'. 2098 */ 2099 static sym_t * 2100 struct_or_union_member(tnode_t *tn, op_t op, sym_t *msym) 2101 { 2102 2103 /* Determine the tag type of which msym is expected to be a member. */ 2104 const type_t *tp = NULL; 2105 if (op == POINT && is_struct_or_union(tn->tn_type->t_tspec)) 2106 tp = tn->tn_type; 2107 if (op == ARROW && tn->tn_type->t_tspec == PTR 2108 && is_struct_or_union(tn->tn_type->t_subt->t_tspec)) 2109 tp = tn->tn_type->t_subt; 2110 struct_or_union *sou = tp != NULL ? tp->u.sou : NULL; 2111 2112 if (sou != NULL) { 2113 sym_t *nested_mem = find_member(sou, msym->s_name); 2114 if (nested_mem != NULL) 2115 return nested_mem; 2116 } 2117 2118 if (msym->s_scl == NO_SCL) { 2119 remove_unknown_member(tn, msym); 2120 return msym; 2121 } 2122 2123 bool eq = all_members_compatible(msym); 2124 2125 /* 2126 * Now handle the case in which the left operand refers really to a 2127 * struct/union, but the right operand is not member of it. 2128 */ 2129 if (sou != NULL) { 2130 if (eq && !allow_c90) 2131 /* illegal use of member '%s' */ 2132 warning(102, msym->s_name); 2133 else 2134 /* illegal use of member '%s' */ 2135 error(102, msym->s_name); 2136 return msym; 2137 } 2138 2139 if (eq) { 2140 if (op == POINT) { 2141 if (!allow_c90) 2142 /* left operand of '.' must be struct ... */ 2143 warning(103, type_name(tn->tn_type)); 2144 else 2145 /* left operand of '.' must be struct ... */ 2146 error(103, type_name(tn->tn_type)); 2147 } else { 2148 if (!allow_c90 && tn->tn_type->t_tspec == PTR) 2149 /* left operand of '->' must be pointer ... */ 2150 warning(104, type_name(tn->tn_type)); 2151 else 2152 /* left operand of '->' must be pointer ... */ 2153 error(104, type_name(tn->tn_type)); 2154 } 2155 } else { 2156 if (!allow_c90) 2157 /* non-unique member requires struct/union %s */ 2158 error(105, op == POINT ? "object" : "pointer"); 2159 else 2160 /* unacceptable operand of '%s' */ 2161 error(111, op_name(op)); 2162 } 2163 2164 return msym; 2165 } 2166 2167 tnode_t * 2168 build_member_access(tnode_t *ln, op_t op, bool sys, sbuf_t *member) 2169 { 2170 sym_t *msym; 2171 2172 if (ln == NULL) 2173 return NULL; 2174 2175 if (op == ARROW) 2176 /* must do this before struct_or_union_member is called */ 2177 ln = cconv(ln); 2178 msym = struct_or_union_member(ln, op, getsym(member)); 2179 return build_binary(ln, op, sys, build_name(msym, false)); 2180 } 2181 2182 /* 2183 * Perform class conversions. 2184 * 2185 * Arrays of type T are converted into pointers to type T. 2186 * Functions are converted to pointers to functions. 2187 * Lvalues are converted to rvalues. 2188 * 2189 * C99 6.3 "Conversions" 2190 * C99 6.3.2 "Other operands" 2191 * C99 6.3.2.1 "Lvalues, arrays, and function designators" 2192 */ 2193 tnode_t * 2194 cconv(tnode_t *tn) 2195 { 2196 if (tn->tn_type->t_tspec == ARRAY) { 2197 if (!tn->tn_lvalue) { 2198 /* XXX print correct operator */ 2199 /* %soperand of '%s' must be lvalue */ 2200 gnuism(114, "", op_name(ADDR)); 2201 } 2202 tn = build_op(ADDR, tn->tn_sys, 2203 expr_derive_type(tn->tn_type->t_subt, PTR), tn, NULL); 2204 } 2205 2206 if (tn->tn_type->t_tspec == FUNC) 2207 tn = build_address(tn->tn_sys, tn, true); 2208 2209 if (tn->tn_lvalue) { 2210 type_t *tp = expr_dup_type(tn->tn_type); 2211 /* C99 6.3.2.1p2 sentence 2 says to remove the qualifiers. */ 2212 tp->t_const = tp->t_volatile = false; 2213 tn = build_op(LOAD, tn->tn_sys, tp, tn, NULL); 2214 } 2215 2216 return tn; 2217 } 2218 2219 const tnode_t * 2220 before_conversion(const tnode_t *tn) 2221 { 2222 while (tn->tn_op == CVT && !tn->tn_cast) 2223 tn = tn->u.ops.left; 2224 return tn; 2225 } 2226 2227 /* 2228 * Most errors required by C90 are reported in struct_or_union_member(). 2229 * Here we only check for totally wrong things. 2230 */ 2231 static bool 2232 typeok_point(const tnode_t *ln, const type_t *ltp, tspec_t lt) 2233 { 2234 if (is_struct_or_union(lt)) 2235 return true; 2236 2237 if (lt == FUNC || lt == VOID || ltp->t_bitfield) 2238 goto wrong; 2239 2240 /* 2241 * Some C dialects from before C90 tolerated any lvalue on the 2242 * left-hand side of the '.' operator, allowing things like 'char 2243 * st[100]; st.st_mtime', assuming that the member 'st_mtime' only 2244 * occurred in a single struct; see typeok_arrow. 2245 */ 2246 if (ln->tn_lvalue) 2247 return true; 2248 2249 wrong: 2250 /* With allow_c90 we already got an error */ 2251 if (!allow_c90) 2252 /* unacceptable operand of '%s' */ 2253 error(111, op_name(POINT)); 2254 2255 return false; 2256 } 2257 2258 static bool 2259 typeok_arrow(tspec_t lt) 2260 { 2261 /* 2262 * C1978 Appendix A 14.1 says: <quote>In fact, any lvalue is allowed 2263 * before '.', and that lvalue is then assumed to have the form of the 2264 * structure of which the name of the right is a member. [...] Such 2265 * constructions are non-portable.</quote> 2266 */ 2267 if (lt == PTR || (!allow_c90 && is_integer(lt))) 2268 return true; 2269 2270 /* With allow_c90 we already got an error */ 2271 if (!allow_c90) 2272 /* unacceptable operand of '%s' */ 2273 error(111, op_name(ARROW)); 2274 return false; 2275 } 2276 2277 static bool 2278 typeok_incdec(op_t op, const tnode_t *tn, const type_t *tp) 2279 { 2280 /* operand has scalar type (checked in typeok) */ 2281 if (!tn->tn_lvalue) { 2282 if (tn->tn_op == CVT && tn->tn_cast && 2283 tn->u.ops.left->tn_op == LOAD) 2284 /* a cast does not yield an lvalue */ 2285 error(163); 2286 /* %soperand of '%s' must be lvalue */ 2287 error(114, "", op_name(op)); 2288 return false; 2289 } 2290 if (tp->t_const && allow_c90) 2291 /* %soperand of '%s' must be modifiable lvalue */ 2292 warning(115, "", op_name(op)); 2293 return true; 2294 } 2295 2296 static bool 2297 typeok_address(op_t op, const tnode_t *tn, const type_t *tp, tspec_t t) 2298 { 2299 if (t == ARRAY || t == FUNC) { 2300 /* ok, a warning comes later (in build_address()) */ 2301 } else if (!tn->tn_lvalue) { 2302 if (tn->tn_op == CVT && tn->tn_cast && 2303 tn->u.ops.left->tn_op == LOAD) 2304 /* a cast does not yield an lvalue */ 2305 error(163); 2306 /* %soperand of '%s' must be lvalue */ 2307 error(114, "", op_name(op)); 2308 return false; 2309 } else if (is_scalar(t)) { 2310 if (tp->t_bitfield) { 2311 /* cannot take address of bit-field */ 2312 error(112); 2313 return false; 2314 } 2315 } else if (t != STRUCT && t != UNION) { 2316 /* unacceptable operand of '%s' */ 2317 error(111, op_name(op)); 2318 return false; 2319 } 2320 if (tn->tn_op == NAME && tn->u.sym->s_register) { 2321 /* cannot take address of register '%s' */ 2322 error(113, tn->u.sym->s_name); 2323 return false; 2324 } 2325 return true; 2326 } 2327 2328 static bool 2329 typeok_indir(const type_t *tp, tspec_t t) 2330 { 2331 2332 if (t != PTR) { 2333 /* cannot dereference non-pointer type '%s' */ 2334 error(96, type_name(tp)); 2335 return false; 2336 } 2337 return true; 2338 } 2339 2340 static void 2341 warn_incompatible_types(op_t op, 2342 const type_t *ltp, tspec_t lt, 2343 const type_t *rtp, tspec_t rt) 2344 { 2345 bool binary = modtab[op].m_binary; 2346 2347 if (lt == VOID || (binary && rt == VOID)) { 2348 /* void type illegal in expression */ 2349 error(109); 2350 } else if (op == ASSIGN) 2351 /* cannot assign to '%s' from '%s' */ 2352 error(171, type_name(ltp), type_name(rtp)); 2353 else if (binary) 2354 /* operands of '%s' have incompatible types '%s' and '%s' */ 2355 error(107, op_name(op), type_name(ltp), type_name(rtp)); 2356 else { 2357 lint_assert(rt == NO_TSPEC); 2358 /* operand of '%s' has invalid type '%s' */ 2359 error(108, op_name(op), type_name(ltp)); 2360 } 2361 } 2362 2363 static bool 2364 typeok_plus(op_t op, 2365 const type_t *ltp, tspec_t lt, 2366 const type_t *rtp, tspec_t rt) 2367 { 2368 /* operands have scalar types (checked in typeok) */ 2369 if ((lt == PTR && !is_integer(rt)) || (rt == PTR && !is_integer(lt))) { 2370 warn_incompatible_types(op, ltp, lt, rtp, rt); 2371 return false; 2372 } 2373 return true; 2374 } 2375 2376 static bool 2377 typeok_minus(op_t op, 2378 const type_t *ltp, tspec_t lt, 2379 const type_t *rtp, tspec_t rt) 2380 { 2381 /* operands have scalar types (checked in typeok) */ 2382 if ((lt == PTR && rt != PTR && !is_integer(rt)) || 2383 (lt != PTR && rt == PTR)) { 2384 warn_incompatible_types(op, ltp, lt, rtp, rt); 2385 return false; 2386 } 2387 if (lt == PTR && rt == PTR && 2388 !types_compatible(ltp->t_subt, rtp->t_subt, true, false, NULL)) { 2389 /* illegal pointer subtraction */ 2390 error(116); 2391 } 2392 return true; 2393 } 2394 2395 static void 2396 typeok_shr(op_t op, 2397 const tnode_t *ln, tspec_t lt, 2398 const tnode_t *rn, tspec_t rt) 2399 { 2400 tspec_t olt = before_conversion(ln)->tn_type->t_tspec; 2401 tspec_t ort = before_conversion(rn)->tn_type->t_tspec; 2402 2403 /* operands have integer types (checked in typeok) */ 2404 if (pflag && !is_uinteger(olt)) { 2405 integer_constraints lc = ic_expr(ln); 2406 if (!ic_maybe_signed(ln->tn_type, &lc)) 2407 return; 2408 2409 if (ln->tn_op != CON) 2410 /* bitwise '%s' on signed value possibly nonportable */ 2411 warning(117, op_name(op)); 2412 else if (ln->u.value.u.integer < 0) 2413 /* bitwise '%s' on signed value nonportable */ 2414 warning(120, op_name(op)); 2415 } else if (allow_trad && allow_c90 && 2416 !is_uinteger(olt) && is_uinteger(ort)) { 2417 /* The left operand would become unsigned in traditional C. */ 2418 if (hflag && (ln->tn_op != CON || ln->u.value.u.integer < 0)) { 2419 /* semantics of '%s' change in C90; use ... */ 2420 warning(118, op_name(op)); 2421 } 2422 } else if (allow_trad && allow_c90 && 2423 !is_uinteger(olt) && !is_uinteger(ort) && 2424 portable_rank_cmp(lt, rt) < 0) { 2425 /* 2426 * In traditional C, the left operand would be extended 2427 * (possibly sign-extended) and then shifted. 2428 */ 2429 if (hflag && (ln->tn_op != CON || ln->u.value.u.integer < 0)) { 2430 /* semantics of '%s' change in C90; use ... */ 2431 warning(118, op_name(op)); 2432 } 2433 } 2434 } 2435 2436 static void 2437 typeok_shl(op_t op, tspec_t lt, tspec_t rt) 2438 { 2439 /* 2440 * C90 does not perform balancing for shift operations, but traditional 2441 * C does. If the width of the right operand is greater than the width 2442 * of the left operand, then in traditional C the left operand would be 2443 * extended to the width of the right operand. For SHL this may result 2444 * in different results. 2445 */ 2446 if (portable_rank_cmp(lt, rt) < 0) { 2447 /* 2448 * XXX If both operands are constant, make sure that there is 2449 * really a difference between C90 and traditional C. 2450 */ 2451 if (hflag && allow_trad && allow_c90) 2452 /* semantics of '%s' change in C90; use ... */ 2453 warning(118, op_name(op)); 2454 } 2455 } 2456 2457 static void 2458 typeok_shift(const type_t *ltp, tspec_t lt, const tnode_t *rn, tspec_t rt) 2459 { 2460 if (rn->tn_op != CON) 2461 return; 2462 2463 if (!is_uinteger(rt) && rn->u.value.u.integer < 0) 2464 /* negative shift */ 2465 warning(121); 2466 else if ((uint64_t)rn->u.value.u.integer == size_in_bits(lt)) 2467 /* shift amount %u equals bit-size of '%s' */ 2468 warning(267, (unsigned)rn->u.value.u.integer, type_name(ltp)); 2469 else if ((uint64_t)rn->u.value.u.integer > size_in_bits(lt)) { 2470 /* shift amount %llu is greater than bit-size %llu of '%s' */ 2471 warning(122, (unsigned long long)rn->u.value.u.integer, 2472 (unsigned long long)size_in_bits(lt), 2473 tspec_name(lt)); 2474 } 2475 } 2476 2477 static bool 2478 is_typeok_eq(const tnode_t *ln, tspec_t lt, const tnode_t *rn, tspec_t rt) 2479 { 2480 if (lt == PTR && is_null_pointer(rn)) 2481 return true; 2482 if (rt == PTR && is_null_pointer(ln)) 2483 return true; 2484 return false; 2485 } 2486 2487 static void 2488 warn_incompatible_pointers(op_t op, const type_t *ltp, const type_t *rtp) 2489 { 2490 lint_assert(ltp->t_tspec == PTR); 2491 lint_assert(rtp->t_tspec == PTR); 2492 2493 tspec_t lt = ltp->t_subt->t_tspec; 2494 tspec_t rt = rtp->t_subt->t_tspec; 2495 2496 if (is_struct_or_union(lt) && is_struct_or_union(rt)) { 2497 if (op == RETURN) 2498 /* illegal structure pointer combination */ 2499 warning(244); 2500 else { 2501 /* incompatible structure pointers: '%s' '%s' '%s' */ 2502 warning(245, type_name(ltp), 2503 op_name(op), type_name(rtp)); 2504 } 2505 } else { 2506 if (op == RETURN) 2507 /* illegal combination of '%s' and '%s' */ 2508 warning(184, type_name(ltp), type_name(rtp)); 2509 else { 2510 /* illegal combination of '%s' and '%s', op '%s' */ 2511 warning(124, 2512 type_name(ltp), type_name(rtp), op_name(op)); 2513 } 2514 } 2515 } 2516 2517 static void 2518 check_pointer_comparison(op_t op, const tnode_t *ln, const tnode_t *rn) 2519 { 2520 type_t *ltp = ln->tn_type, *rtp = rn->tn_type; 2521 tspec_t lst = ltp->t_subt->t_tspec, rst = rtp->t_subt->t_tspec; 2522 2523 if (lst == VOID || rst == VOID) { 2524 /* TODO: C99 behaves like C90 here. */ 2525 if (!allow_trad && !allow_c99 && 2526 (lst == FUNC || rst == FUNC)) { 2527 /* (void *)0 is already handled in typeok() */ 2528 const char *lsts, *rsts; 2529 *(lst == FUNC ? &lsts : &rsts) = "function pointer"; 2530 *(lst == VOID ? &lsts : &rsts) = "'void *'"; 2531 /* C90 or later forbid comparison of %s with %s */ 2532 warning(274, lsts, rsts); 2533 } 2534 return; 2535 } 2536 2537 if (!types_compatible(ltp->t_subt, rtp->t_subt, true, false, NULL)) { 2538 warn_incompatible_pointers(op, ltp, rtp); 2539 return; 2540 } 2541 2542 if (lst == FUNC && rst == FUNC) { 2543 /* TODO: C99 behaves like C90 here, see C99 6.5.8p2. */ 2544 if (!allow_trad && !allow_c99 && op != EQ && op != NE) 2545 /* pointers to functions can only be compared ... */ 2546 warning(125); 2547 } 2548 } 2549 2550 static bool 2551 typeok_compare(op_t op, 2552 const tnode_t *ln, const type_t *ltp, tspec_t lt, 2553 const tnode_t *rn, const type_t *rtp, tspec_t rt) 2554 { 2555 if (lt == PTR && rt == PTR) { 2556 check_pointer_comparison(op, ln, rn); 2557 return true; 2558 } 2559 2560 if (lt != PTR && rt != PTR) 2561 return true; 2562 2563 if (!is_integer(lt) && !is_integer(rt)) { 2564 warn_incompatible_types(op, ltp, lt, rtp, rt); 2565 return false; 2566 } 2567 2568 const char *lx = lt == PTR ? "pointer" : "integer"; 2569 const char *rx = rt == PTR ? "pointer" : "integer"; 2570 /* illegal combination of %s '%s' and %s '%s', op '%s' */ 2571 warning(123, lx, type_name(ltp), rx, type_name(rtp), op_name(op)); 2572 return true; 2573 } 2574 2575 static bool 2576 typeok_quest(tspec_t lt, const tnode_t *rn) 2577 { 2578 if (!is_scalar(lt)) { 2579 /* first operand of '?' must have scalar type */ 2580 error(170); 2581 return false; 2582 } 2583 lint_assert(before_conversion(rn)->tn_op == COLON); 2584 return true; 2585 } 2586 2587 static void 2588 typeok_colon_pointer(const type_t *ltp, const type_t *rtp) 2589 { 2590 type_t *lstp = ltp->t_subt; 2591 type_t *rstp = rtp->t_subt; 2592 tspec_t lst = lstp->t_tspec; 2593 tspec_t rst = rstp->t_tspec; 2594 2595 if ((lst == VOID && rst == FUNC) || (lst == FUNC && rst == VOID)) { 2596 /* (void *)0 is handled in typeok_colon */ 2597 /* TODO: C99 behaves like C90 here. */ 2598 if (!allow_trad && !allow_c99) 2599 /* conversion of %s to %s requires a cast, op %s */ 2600 warning(305, "function pointer", "'void *'", 2601 op_name(COLON)); 2602 return; 2603 } 2604 2605 if (pointer_types_are_compatible(lstp, rstp, true)) 2606 return; 2607 if (!types_compatible(lstp, rstp, true, false, NULL)) 2608 warn_incompatible_pointers(COLON, ltp, rtp); 2609 } 2610 2611 static bool 2612 typeok_colon(const tnode_t *ln, const type_t *ltp, tspec_t lt, 2613 const tnode_t *rn, const type_t *rtp, tspec_t rt) 2614 { 2615 2616 if (is_arithmetic(lt) && is_arithmetic(rt)) 2617 return true; 2618 if (lt == BOOL && rt == BOOL) 2619 return true; 2620 2621 if (lt == STRUCT && rt == STRUCT && ltp->u.sou == rtp->u.sou) 2622 return true; 2623 if (lt == UNION && rt == UNION && ltp->u.sou == rtp->u.sou) 2624 return true; 2625 2626 if (lt == PTR && is_null_pointer(rn)) 2627 return true; 2628 if (rt == PTR && is_null_pointer(ln)) 2629 return true; 2630 2631 if ((lt == PTR && is_integer(rt)) || (is_integer(lt) && rt == PTR)) { 2632 const char *lx = lt == PTR ? "pointer" : "integer"; 2633 const char *rx = rt == PTR ? "pointer" : "integer"; 2634 /* illegal combination of %s '%s' and %s '%s', op '%s' */ 2635 warning(123, lx, type_name(ltp), 2636 rx, type_name(rtp), op_name(COLON)); 2637 return true; 2638 } 2639 2640 if (lt == VOID || rt == VOID) { 2641 if (lt != VOID || rt != VOID) 2642 /* incompatible types '%s' and '%s' in conditional */ 2643 warning(126, type_name(ltp), type_name(rtp)); 2644 return true; 2645 } 2646 2647 if (lt == PTR && rt == PTR) { 2648 typeok_colon_pointer(ltp, rtp); 2649 return true; 2650 } 2651 2652 /* incompatible types '%s' and '%s' in conditional */ 2653 error(126, type_name(ltp), type_name(rtp)); 2654 return false; 2655 } 2656 2657 static bool 2658 has_constant_member(const type_t *tp) 2659 { 2660 lint_assert(is_struct_or_union(tp->t_tspec)); 2661 2662 for (sym_t *m = tp->u.sou->sou_first_member; 2663 m != NULL; m = m->s_next) { 2664 const type_t *mtp = m->s_type; 2665 if (mtp->t_const) 2666 return true; 2667 if (is_struct_or_union(mtp->t_tspec) && 2668 has_constant_member(mtp)) 2669 return true; 2670 } 2671 return false; 2672 } 2673 2674 static bool 2675 typeok_assign(op_t op, const tnode_t *ln, const type_t *ltp, tspec_t lt) 2676 { 2677 if (op == RETURN || op == INIT || op == FARG) 2678 return true; 2679 2680 if (!ln->tn_lvalue) { 2681 if (ln->tn_op == CVT && ln->tn_cast && 2682 ln->u.ops.left->tn_op == LOAD) 2683 /* a cast does not yield an lvalue */ 2684 error(163); 2685 /* %soperand of '%s' must be lvalue */ 2686 error(114, "left ", op_name(op)); 2687 return false; 2688 } else if (ltp->t_const 2689 || (is_struct_or_union(lt) && has_constant_member(ltp))) { 2690 if (allow_c90) 2691 /* %soperand of '%s' must be modifiable lvalue */ 2692 warning(115, "left ", op_name(op)); 2693 } 2694 return true; 2695 } 2696 2697 static bool 2698 typeok_scalar(op_t op, const mod_t *mp, 2699 const type_t *ltp, tspec_t lt, 2700 const type_t *rtp, tspec_t rt) 2701 { 2702 if (mp->m_takes_bool && lt == BOOL && rt == BOOL) 2703 return true; 2704 if (mp->m_requires_integer) { 2705 if (!is_integer(lt) || (mp->m_binary && !is_integer(rt))) { 2706 warn_incompatible_types(op, ltp, lt, rtp, rt); 2707 return false; 2708 } 2709 } else if (mp->m_requires_integer_or_complex) { 2710 if ((!is_integer(lt) && !is_complex(lt)) || 2711 (mp->m_binary && (!is_integer(rt) && !is_complex(rt)))) { 2712 warn_incompatible_types(op, ltp, lt, rtp, rt); 2713 return false; 2714 } 2715 } else if (mp->m_requires_scalar) { 2716 if (!is_scalar(lt) || (mp->m_binary && !is_scalar(rt))) { 2717 warn_incompatible_types(op, ltp, lt, rtp, rt); 2718 return false; 2719 } 2720 } else if (mp->m_requires_arith) { 2721 if (!is_arithmetic(lt) || 2722 (mp->m_binary && !is_arithmetic(rt))) { 2723 warn_incompatible_types(op, ltp, lt, rtp, rt); 2724 return false; 2725 } 2726 } 2727 return true; 2728 } 2729 2730 static void 2731 check_assign_void_pointer(op_t op, int arg, 2732 tspec_t lt, tspec_t lst, 2733 tspec_t rt, tspec_t rst) 2734 { 2735 2736 if (!(lt == PTR && rt == PTR && (lst == VOID || rst == VOID))) 2737 return; 2738 /* two pointers, at least one pointer to void */ 2739 2740 /* TODO: C99 behaves like C90 here. */ 2741 if (!(!allow_trad && !allow_c99 && (lst == FUNC || rst == FUNC))) 2742 return; 2743 /* comb. of ptr to func and ptr to void */ 2744 2745 const char *lts, *rts; 2746 *(lst == FUNC ? <s : &rts) = "function pointer"; 2747 *(lst == VOID ? <s : &rts) = "'void *'"; 2748 2749 switch (op) { 2750 case INIT: 2751 case RETURN: 2752 /* conversion of %s to %s requires a cast */ 2753 warning(303, rts, lts); 2754 break; 2755 case FARG: 2756 /* conversion of %s to %s requires a cast, arg #%d */ 2757 warning(304, rts, lts, arg); 2758 break; 2759 default: 2760 /* conversion of %s to %s requires a cast, op %s */ 2761 warning(305, rts, lts, op_name(op)); 2762 break; 2763 } 2764 } 2765 2766 static bool 2767 is_direct_function_call(const tnode_t *tn, const char **out_name) 2768 { 2769 2770 if (tn->tn_op == CALL 2771 && tn->u.call->func->tn_op == ADDR 2772 && tn->u.call->func->u.ops.left->tn_op == NAME) { 2773 *out_name = tn->u.call->func->u.ops.left->u.sym->s_name; 2774 return true; 2775 } 2776 return false; 2777 } 2778 2779 static bool 2780 is_unconst_function(const char *name) 2781 { 2782 2783 return strcmp(name, "memchr") == 0 || 2784 strcmp(name, "strchr") == 0 || 2785 strcmp(name, "strpbrk") == 0 || 2786 strcmp(name, "strrchr") == 0 || 2787 strcmp(name, "strstr") == 0; 2788 } 2789 2790 static bool 2791 is_const_char_pointer(const tnode_t *tn) 2792 { 2793 /* 2794 * For traditional reasons, C99 6.4.5p5 defines that string literals 2795 * have type 'char[]'. They are often implicitly converted to 'char 2796 * *', for example when they are passed as function arguments. 2797 * 2798 * C99 6.4.5p6 further defines that modifying a string that is 2799 * constructed from a string literal invokes undefined behavior. 2800 * 2801 * Out of these reasons, string literals are treated as 'effectively 2802 * const' here. 2803 */ 2804 if (tn->tn_op == CVT && 2805 tn->u.ops.left->tn_op == ADDR && 2806 tn->u.ops.left->u.ops.left->tn_op == STRING) 2807 return true; 2808 2809 const type_t *tp = before_conversion(tn)->tn_type; 2810 return tp->t_tspec == PTR && 2811 tp->t_subt->t_tspec == CHAR && 2812 tp->t_subt->t_const; 2813 } 2814 2815 static bool 2816 is_const_pointer(const tnode_t *tn) 2817 { 2818 const type_t *tp = before_conversion(tn)->tn_type; 2819 return tp->t_tspec == PTR && tp->t_subt->t_const; 2820 } 2821 2822 static void 2823 check_unconst_function(const type_t *lstp, const tnode_t *rn) 2824 { 2825 const char *function_name; 2826 2827 if (lstp->t_tspec == CHAR && !lstp->t_const && 2828 is_direct_function_call(rn, &function_name) && 2829 is_unconst_function(function_name) && 2830 rn->u.call->args_len >= 1 && 2831 is_const_char_pointer(rn->u.call->args[0])) { 2832 /* call to '%s' effectively discards 'const' from argument */ 2833 warning(346, function_name); 2834 } 2835 2836 if (!lstp->t_const && 2837 is_direct_function_call(rn, &function_name) && 2838 strcmp(function_name, "bsearch") == 0 && 2839 rn->u.call->args_len >= 2 && 2840 is_const_pointer(rn->u.call->args[1])) { 2841 /* call to '%s' effectively discards 'const' from argument */ 2842 warning(346, function_name); 2843 } 2844 } 2845 2846 static bool 2847 check_assign_void_pointer_compat(op_t op, int arg, 2848 const type_t *ltp, tspec_t lt, 2849 const type_t *lstp, tspec_t lst, 2850 const tnode_t *rn, 2851 const type_t *rtp, tspec_t rt, 2852 const type_t *rstp, tspec_t rst) 2853 { 2854 if (!(lt == PTR && rt == PTR && (lst == VOID || rst == VOID || 2855 types_compatible(lstp, rstp, 2856 true, false, NULL)))) 2857 return false; 2858 2859 /* compatible pointer types (qualifiers ignored) */ 2860 char qualifiers[32]; 2861 snprintf(qualifiers, sizeof(qualifiers), "%s%s", 2862 !lstp->t_const && rstp->t_const ? " const" : "", 2863 !lstp->t_volatile && rstp->t_volatile ? " volatile" : ""); 2864 if (allow_c90 && qualifiers[0] != '\0') { 2865 switch (op) { 2866 case INIT: 2867 case RETURN: 2868 /* '%s' discards '%s' from '%s' */ 2869 warning(182, op_name(op), 2870 qualifiers + 1, type_name(rtp)); 2871 break; 2872 case FARG: 2873 /* converting '%s' to incompatible '%s' ... */ 2874 warning(153, 2875 type_name(rtp), type_name(ltp), arg); 2876 break; 2877 default: 2878 /* operator '%s' discards '%s' from '%s' */ 2879 warning(128, op_name(op), 2880 qualifiers + 1, type_name(rtp)); 2881 break; 2882 } 2883 } 2884 2885 if (allow_c90) 2886 check_unconst_function(lstp, rn); 2887 2888 return true; 2889 } 2890 2891 static bool 2892 check_assign_pointer_integer(op_t op, int arg, 2893 const type_t *ltp, tspec_t lt, 2894 const type_t *rtp, tspec_t rt) 2895 { 2896 2897 if (!((lt == PTR && is_integer(rt)) || (is_integer(lt) && rt == PTR))) 2898 return false; 2899 2900 const char *lx = lt == PTR ? "pointer" : "integer"; 2901 const char *rx = rt == PTR ? "pointer" : "integer"; 2902 2903 switch (op) { 2904 case INIT: 2905 case RETURN: 2906 /* illegal combination of %s '%s' and %s '%s' */ 2907 warning(183, lx, type_name(ltp), rx, type_name(rtp)); 2908 break; 2909 case FARG: 2910 /* illegal combination of %s '%s' and %s '%s', arg #%d */ 2911 warning(154, 2912 lx, type_name(ltp), rx, type_name(rtp), arg); 2913 break; 2914 default: 2915 /* illegal combination of %s '%s' and %s '%s', op '%s' */ 2916 warning(123, 2917 lx, type_name(ltp), rx, type_name(rtp), op_name(op)); 2918 break; 2919 } 2920 return true; 2921 } 2922 2923 static bool 2924 check_assign_pointer(op_t op, int arg, 2925 const type_t *ltp, tspec_t lt, 2926 const type_t *rtp, tspec_t rt) 2927 { 2928 if (!(lt == PTR && rt == PTR)) 2929 return false; 2930 2931 if (op == FARG) 2932 /* converting '%s' to incompatible '%s' for ... */ 2933 warning(153, type_name(rtp), type_name(ltp), arg); 2934 else 2935 warn_incompatible_pointers(op, ltp, rtp); 2936 return true; 2937 } 2938 2939 static void 2940 warn_assign(op_t op, int arg, 2941 const type_t *ltp, tspec_t lt, 2942 const type_t *rtp, tspec_t rt) 2943 { 2944 switch (op) { 2945 case INIT: 2946 /* cannot initialize '%s' from '%s' */ 2947 error(185, type_name(ltp), type_name(rtp)); 2948 break; 2949 case RETURN: 2950 /* function has return type '%s' but returns '%s' */ 2951 error(211, type_name(ltp), type_name(rtp)); 2952 break; 2953 case FARG: 2954 /* passing '%s' to incompatible '%s', arg #%d */ 2955 warning(155, type_name(rtp), type_name(ltp), arg); 2956 break; 2957 default: 2958 warn_incompatible_types(op, ltp, lt, rtp, rt); 2959 break; 2960 } 2961 } 2962 2963 /* 2964 * Checks type compatibility for ASSIGN, INIT, FARG and RETURN 2965 * and prints warnings/errors if necessary. 2966 * Returns whether the types are (almost) compatible. 2967 */ 2968 static bool 2969 check_assign_types_compatible(op_t op, int arg, 2970 const tnode_t *ln, const tnode_t *rn) 2971 { 2972 tspec_t lt, rt, lst = NO_TSPEC, rst = NO_TSPEC; 2973 type_t *ltp, *rtp, *lstp = NULL, *rstp = NULL; 2974 2975 if ((lt = (ltp = ln->tn_type)->t_tspec) == PTR) 2976 lst = (lstp = ltp->t_subt)->t_tspec; 2977 if ((rt = (rtp = rn->tn_type)->t_tspec) == PTR) 2978 rst = (rstp = rtp->t_subt)->t_tspec; 2979 2980 if (lt == BOOL && is_scalar(rt)) /* C99 6.3.1.2 */ 2981 return true; 2982 2983 if (is_arithmetic(lt) && (is_arithmetic(rt) || rt == BOOL)) 2984 return true; 2985 2986 if (is_struct_or_union(lt) && is_struct_or_union(rt)) 2987 return ltp->u.sou == rtp->u.sou; 2988 2989 if (lt == PTR && is_null_pointer(rn)) { 2990 if (is_integer(rn->tn_type->t_tspec)) 2991 /* implicit conversion from integer 0 to pointer ... */ 2992 query_message(15, type_name(ltp)); 2993 return true; 2994 } 2995 2996 check_assign_void_pointer(op, arg, lt, lst, rt, rst); 2997 2998 if (check_assign_void_pointer_compat(op, arg, 2999 ltp, lt, lstp, lst, rn, rtp, rt, rstp, rst)) 3000 return true; 3001 3002 if (check_assign_pointer_integer(op, arg, ltp, lt, rtp, rt)) 3003 return true; 3004 3005 if (check_assign_pointer(op, arg, ltp, lt, rtp, rt)) 3006 return true; 3007 3008 warn_assign(op, arg, ltp, lt, rtp, rt); 3009 return false; 3010 } 3011 3012 static bool 3013 has_side_effect(const tnode_t *tn) /* NOLINT(misc-no-recursion) */ 3014 { 3015 op_t op = tn->tn_op; 3016 3017 if (modtab[op].m_has_side_effect) 3018 return true; 3019 3020 if (op == CVT && tn->tn_type->t_tspec == VOID) 3021 return has_side_effect(tn->u.ops.left); 3022 3023 /* XXX: Why not has_side_effect(tn->u.ops.left) as well? */ 3024 if (op == LOGAND || op == LOGOR) 3025 return has_side_effect(tn->u.ops.right); 3026 3027 /* XXX: Why not has_side_effect(tn->u.ops.left) as well? */ 3028 if (op == QUEST) 3029 return has_side_effect(tn->u.ops.right); 3030 3031 if (op == COLON || op == COMMA) { 3032 return has_side_effect(tn->u.ops.left) || 3033 has_side_effect(tn->u.ops.right); 3034 } 3035 3036 return false; 3037 } 3038 3039 static bool 3040 is_void_cast(const tnode_t *tn) 3041 { 3042 3043 return tn->tn_op == CVT && tn->tn_cast && 3044 tn->tn_type->t_tspec == VOID; 3045 } 3046 3047 static bool 3048 is_local_symbol(const tnode_t *tn) 3049 { 3050 3051 return tn->tn_op == LOAD && 3052 tn->u.ops.left->tn_op == NAME && 3053 tn->u.ops.left->u.sym->s_scl == AUTO; 3054 } 3055 3056 static bool 3057 is_int_constant_zero(const tnode_t *tn) 3058 { 3059 3060 return tn->tn_op == CON && 3061 tn->tn_type->t_tspec == INT && 3062 tn->u.value.u.integer == 0; 3063 } 3064 3065 static void 3066 check_null_effect(const tnode_t *tn) 3067 { 3068 3069 if (hflag && 3070 !has_side_effect(tn) && 3071 !(is_void_cast(tn) && is_local_symbol(tn->u.ops.left)) && 3072 !(is_void_cast(tn) && is_int_constant_zero(tn->u.ops.left))) { 3073 /* expression has null effect */ 3074 warning(129); 3075 } 3076 } 3077 3078 /* 3079 * Check the types for specific operators and type combinations. 3080 * 3081 * At this point, the operands already conform to the type requirements of 3082 * the operator, such as being integer, floating or scalar. 3083 */ 3084 static bool 3085 typeok_op(op_t op, int arg, 3086 const tnode_t *ln, const type_t *ltp, tspec_t lt, 3087 const tnode_t *rn, const type_t *rtp, tspec_t rt) 3088 { 3089 switch (op) { 3090 case ARROW: 3091 return typeok_arrow(lt); 3092 case POINT: 3093 return typeok_point(ln, ltp, lt); 3094 case INCBEF: 3095 case DECBEF: 3096 case INCAFT: 3097 case DECAFT: 3098 return typeok_incdec(op, ln, ltp); 3099 case INDIR: 3100 return typeok_indir(ltp, lt); 3101 case ADDR: 3102 return typeok_address(op, ln, ltp, lt); 3103 case PLUS: 3104 return typeok_plus(op, ltp, lt, rtp, rt); 3105 case MINUS: 3106 return typeok_minus(op, ltp, lt, rtp, rt); 3107 case SHL: 3108 typeok_shl(op, lt, rt); 3109 goto shift; 3110 case SHR: 3111 typeok_shr(op, ln, lt, rn, rt); 3112 shift: 3113 typeok_shift(ltp, lt, rn, rt); 3114 break; 3115 case LT: 3116 case LE: 3117 case GT: 3118 case GE: 3119 compare: 3120 return typeok_compare(op, ln, ltp, lt, rn, rtp, rt); 3121 case EQ: 3122 case NE: 3123 if (is_typeok_eq(ln, lt, rn, rt)) 3124 break; 3125 goto compare; 3126 case QUEST: 3127 return typeok_quest(lt, rn); 3128 case COLON: 3129 return typeok_colon(ln, ltp, lt, rn, rtp, rt); 3130 case ASSIGN: 3131 case INIT: 3132 case FARG: 3133 case RETURN: 3134 if (!check_assign_types_compatible(op, arg, ln, rn)) 3135 return false; 3136 goto assign; 3137 case MULASS: 3138 case DIVASS: 3139 case MODASS: 3140 goto assign; 3141 case ADDASS: 3142 case SUBASS: 3143 if ((lt == PTR && !is_integer(rt)) || rt == PTR) { 3144 warn_incompatible_types(op, ltp, lt, rtp, rt); 3145 return false; 3146 } 3147 goto assign; 3148 case SHLASS: 3149 goto assign; 3150 case SHRASS: 3151 if (pflag && !is_uinteger(lt) && 3152 !(!allow_c90 && is_uinteger(rt))) { 3153 /* bitwise '%s' on signed value possibly nonportable */ 3154 warning(117, op_name(op)); 3155 } 3156 goto assign; 3157 case ANDASS: 3158 case XORASS: 3159 case ORASS: 3160 assign: 3161 return typeok_assign(op, ln, ltp, lt); 3162 case COMMA: 3163 if (!modtab[ln->tn_op].m_has_side_effect) 3164 check_null_effect(ln); 3165 break; 3166 default: 3167 break; 3168 } 3169 return true; 3170 } 3171 3172 static void 3173 check_bad_enum_operation(op_t op, const tnode_t *ln, const tnode_t *rn) 3174 { 3175 3176 if (!eflag) 3177 return; 3178 3179 /* Allow enum in array indices. */ 3180 if (op == PLUS && 3181 ((ln->tn_type->t_is_enum && rn->tn_type->t_tspec == PTR) || 3182 (rn->tn_type->t_is_enum && ln->tn_type->t_tspec == PTR))) { 3183 return; 3184 } 3185 3186 /* dubious operation '%s' on enum */ 3187 warning(241, op_name(op)); 3188 } 3189 3190 static void 3191 check_enum_type_mismatch(op_t op, int arg, const tnode_t *ln, const tnode_t *rn) 3192 { 3193 const mod_t *mp = &modtab[op]; 3194 3195 if (ln->tn_type->u.enumer != rn->tn_type->u.enumer) { 3196 switch (op) { 3197 case INIT: 3198 /* enum type mismatch between '%s' and '%s' in ... */ 3199 warning(210, 3200 type_name(ln->tn_type), type_name(rn->tn_type)); 3201 break; 3202 case FARG: 3203 /* function expects '%s', passing '%s' for arg #%d */ 3204 warning(156, 3205 type_name(ln->tn_type), type_name(rn->tn_type), 3206 arg); 3207 break; 3208 case RETURN: 3209 /* function has return type '%s' but returns '%s' */ 3210 warning(211, 3211 type_name(ln->tn_type), type_name(rn->tn_type)); 3212 break; 3213 default: 3214 /* enum type mismatch: '%s' '%s' '%s' */ 3215 warning(130, type_name(ln->tn_type), op_name(op), 3216 type_name(rn->tn_type)); 3217 break; 3218 } 3219 } else if (Pflag && eflag && mp->m_comparison && op != EQ && op != NE) 3220 /* operator '%s' assumes that '%s' is ordered */ 3221 warning(243, op_name(op), type_name(ln->tn_type)); 3222 } 3223 3224 static void 3225 check_enum_int_mismatch(op_t op, int arg, const tnode_t *ln, const tnode_t *rn) 3226 { 3227 3228 if (!eflag) 3229 return; 3230 3231 switch (op) { 3232 case INIT: 3233 /* 3234 * Initialization with 0 is allowed. Otherwise, all implicit 3235 * initializations would need to be warned upon as well. 3236 */ 3237 if (!rn->tn_type->t_is_enum && rn->tn_op == CON && 3238 is_integer(rn->tn_type->t_tspec) && 3239 rn->u.value.u.integer == 0) { 3240 return; 3241 } 3242 /* initialization of '%s' with '%s' */ 3243 warning(277, type_name(ln->tn_type), type_name(rn->tn_type)); 3244 break; 3245 case FARG: 3246 /* combination of '%s' and '%s', arg #%d */ 3247 warning(278, 3248 type_name(ln->tn_type), type_name(rn->tn_type), arg); 3249 break; 3250 case RETURN: 3251 /* combination of '%s' and '%s' in return */ 3252 warning(279, type_name(ln->tn_type), type_name(rn->tn_type)); 3253 break; 3254 default: 3255 /* combination of '%s' and '%s', op '%s' */ 3256 warning(242, type_name(ln->tn_type), type_name(rn->tn_type), 3257 op_name(op)); 3258 break; 3259 } 3260 } 3261 3262 static void 3263 typeok_enum(op_t op, const mod_t *mp, int arg, 3264 const tnode_t *ln, const type_t *ltp, 3265 const tnode_t *rn, const type_t *rtp) 3266 { 3267 if (mp->m_bad_on_enum && 3268 (ltp->t_is_enum || (mp->m_binary && rtp->t_is_enum))) { 3269 check_bad_enum_operation(op, ln, rn); 3270 } else if (mp->m_valid_on_enum && 3271 (ltp->t_is_enum && rtp != NULL && rtp->t_is_enum)) { 3272 check_enum_type_mismatch(op, arg, ln, rn); 3273 } else if (mp->m_valid_on_enum && 3274 (ltp->t_is_enum || (rtp != NULL && rtp->t_is_enum))) { 3275 check_enum_int_mismatch(op, arg, ln, rn); 3276 } 3277 } 3278 3279 /* Perform most type checks. Return whether the types are ok. */ 3280 bool 3281 typeok(op_t op, int arg, const tnode_t *ln, const tnode_t *rn) 3282 { 3283 3284 const mod_t *mp = &modtab[op]; 3285 3286 type_t *ltp = ln->tn_type; 3287 tspec_t lt = ltp->t_tspec; 3288 3289 type_t *rtp = mp->m_binary ? rn->tn_type : NULL; 3290 tspec_t rt = mp->m_binary ? rtp->t_tspec : NO_TSPEC; 3291 3292 if (Tflag && !typeok_scalar_strict_bool(op, mp, arg, ln, rn)) 3293 return false; 3294 if (!typeok_scalar(op, mp, ltp, lt, rtp, rt)) 3295 return false; 3296 3297 if (!typeok_op(op, arg, ln, ltp, lt, rn, rtp, rt)) 3298 return false; 3299 3300 typeok_enum(op, mp, arg, ln, ltp, rn, rtp); 3301 return true; 3302 } 3303 3304 /* In traditional C, keep unsigned and promote FLOAT to DOUBLE. */ 3305 static tspec_t 3306 promote_trad(tspec_t t) 3307 { 3308 3309 if (t == UCHAR || t == USHORT) 3310 return UINT; 3311 if (t == CHAR || t == SCHAR || t == SHORT) 3312 return INT; 3313 if (t == FLOAT) 3314 return DOUBLE; 3315 if (t == ENUM) 3316 return INT; 3317 return t; 3318 } 3319 3320 /* 3321 * C99 6.3.1.1p2 requires for types with lower rank than int that "If an int 3322 * can represent all the values of the original type, the value is converted 3323 * to an int; otherwise it is converted to an unsigned int", and that "All 3324 * other types are unchanged by the integer promotions". 3325 */ 3326 static tspec_t 3327 promote_c90(const tnode_t *tn, tspec_t t, bool farg) 3328 { 3329 if (tn->tn_type->t_bitfield) { 3330 unsigned int width = tn->tn_type->t_bit_field_width; 3331 unsigned int int_width = size_in_bits(INT); 3332 // XXX: What about _Bool bit-fields, since C99? 3333 if (width < int_width) 3334 return INT; 3335 if (width == int_width) 3336 return is_uinteger(t) ? UINT : INT; 3337 return t; 3338 } 3339 3340 if (t == CHAR || t == SCHAR) 3341 return INT; 3342 if (t == UCHAR) 3343 return size_in_bits(CHAR) < size_in_bits(INT) ? INT : UINT; 3344 if (t == SHORT) 3345 return INT; 3346 if (t == USHORT) 3347 return size_in_bits(SHORT) < size_in_bits(INT) ? INT : UINT; 3348 if (t == ENUM) 3349 return INT; 3350 if (farg && t == FLOAT) 3351 return DOUBLE; 3352 return t; 3353 } 3354 3355 /* 3356 * Performs the "integer promotions" (C99 6.3.1.1p2), which convert small 3357 * integer types to either int or unsigned int. 3358 * 3359 * If allow_c90 is unset or the operand is a function argument with no type 3360 * information (no prototype or variable # of args), converts float to double. 3361 */ 3362 tnode_t * 3363 promote(op_t op, bool farg, tnode_t *tn) 3364 { 3365 3366 const type_t *otp = tn->tn_type; 3367 tspec_t ot = otp->t_tspec; 3368 if (!is_arithmetic(ot)) 3369 return tn; 3370 3371 tspec_t nt = allow_c90 ? promote_c90(tn, ot, farg) : promote_trad(ot); 3372 if (nt == ot) 3373 return tn; 3374 3375 type_t *ntp = expr_dup_type(gettyp(nt)); 3376 ntp->t_tspec = nt; 3377 ntp->t_is_enum = otp->t_is_enum; 3378 if (ntp->t_is_enum) 3379 ntp->u.enumer = otp->u.enumer; 3380 ntp->t_bitfield = otp->t_bitfield; 3381 if (ntp->t_bitfield) { 3382 ntp->t_bit_field_width = otp->t_bit_field_width; 3383 ntp->t_bit_field_offset = otp->t_bit_field_offset; 3384 } 3385 if (ntp->t_bitfield && is_uinteger(ot) && !is_uinteger(nt)) 3386 ntp->t_bit_field_width++; 3387 return convert(op, 0, ntp, tn); 3388 } 3389 3390 static void 3391 check_lossy_floating_to_integer_conversion( 3392 op_t op, int arg, const type_t *tp, const tnode_t *tn) 3393 { 3394 long double x = tn->u.value.u.floating; 3395 integer_constraints ic = ic_any(tp); 3396 if (is_uinteger(tp->t_tspec) 3397 ? x >= ic.umin && x <= ic.umax && x == (uint64_t)x 3398 : x >= ic.smin && x <= ic.smax && x == (int64_t)x) 3399 return; 3400 if (op == FARG) 3401 /* lossy conversion of %Lg to '%s', arg #%d */ 3402 warning(380, x, type_name(tp), arg); 3403 else 3404 /* lossy conversion of %Lg to '%s' */ 3405 warning(381, x, type_name(tp)); 3406 } 3407 3408 static void 3409 convert_integer_from_floating( 3410 op_t op, int arg, const type_t *tp, const tnode_t *tn) 3411 { 3412 3413 if (op == CVT) 3414 /* cast from floating point '%s' to integer '%s' */ 3415 query_message(2, type_name(tn->tn_type), type_name(tp)); 3416 else 3417 /* implicit conversion from floating point '%s' to ... */ 3418 query_message(1, type_name(tn->tn_type), type_name(tp)); 3419 if (tn->tn_op == CON) 3420 check_lossy_floating_to_integer_conversion(op, arg, tp, tn); 3421 } 3422 3423 static bool 3424 should_warn_about_prototype_conversion(tspec_t nt, 3425 tspec_t ot, const tnode_t *ptn) 3426 { 3427 3428 if (nt == ot) 3429 return false; 3430 3431 if (nt == ENUM && ot == INT) 3432 return false; 3433 3434 if (is_floating(nt) != is_floating(ot) || 3435 portable_rank_cmp(nt, ot) != 0) { 3436 /* representation and/or width change */ 3437 if (!is_integer(ot)) 3438 return true; 3439 /* 3440 * XXX: Investigate whether this rule makes sense; see 3441 * tests/usr.bin/xlint/lint1/platform_long.c. 3442 */ 3443 return portable_rank_cmp(ot, INT) > 0; 3444 } 3445 3446 if (!hflag) 3447 return false; 3448 3449 /* 3450 * If the types differ only in sign and the argument has the same 3451 * representation in both types, print no warning. 3452 */ 3453 if (ptn->tn_op == CON && is_integer(nt) && 3454 signed_type(nt) == signed_type(ot) && 3455 !msb(ptn->u.value.u.integer, ot)) 3456 return false; 3457 3458 return true; 3459 } 3460 3461 /* 3462 * Warn if a prototype causes a type conversion that is different from what 3463 * would happen to the same argument in the absence of a prototype. This 3464 * check is intended for code that needs to stay compatible with pre-C90 C. 3465 * 3466 * Errors/warnings about illegal type combinations are already printed 3467 * in check_assign_types_compatible(). 3468 */ 3469 static void 3470 check_prototype_conversion(int arg, tspec_t nt, tspec_t ot, type_t *tp, 3471 tnode_t *tn) 3472 { 3473 3474 if (!is_arithmetic(nt) || !is_arithmetic(ot)) 3475 return; 3476 3477 /* 3478 * If the type of the formal parameter is char/short, a warning would 3479 * be useless, because functions declared the old style can't expect 3480 * char/short arguments. 3481 */ 3482 if (nt == CHAR || nt == SCHAR || nt == UCHAR || 3483 nt == SHORT || nt == USHORT) 3484 return; 3485 3486 tnode_t *ptn = promote(NOOP, true, tn); 3487 ot = ptn->tn_type->t_tspec; 3488 3489 if (should_warn_about_prototype_conversion(nt, ot, ptn)) { 3490 /* argument %d is converted from '%s' to '%s' ... */ 3491 warning(259, arg, type_name(tn->tn_type), type_name(tp)); 3492 } 3493 } 3494 3495 /* 3496 * When converting a large integer type to a small integer type, in some 3497 * cases the value of the actual expression is further restricted than the 3498 * type bounds, such as in (expr & 0xFF) or (expr % 100) or (expr >> 24). 3499 */ 3500 static bool 3501 can_represent(const type_t *tp, const tnode_t *tn) 3502 { 3503 uint64_t nmask = value_bits(width_in_bits(tp)); 3504 if (!is_uinteger(tp->t_tspec)) 3505 nmask >>= 1; 3506 3507 integer_constraints c = ic_expr(tn); 3508 if ((~c.bclr & ~nmask) == 0) 3509 return true; 3510 3511 integer_constraints tpc = ic_any(tp); 3512 if (is_uinteger(tp->t_tspec) 3513 ? tpc.umin <= c.umin && tpc.umax >= c.umax 3514 : tpc.smin <= c.smin && tpc.smax >= c.smax) 3515 return true; 3516 3517 debug_enter(); 3518 debug_step("type '%s' cannot represent:", type_name(tp)); 3519 debug_node(tn); 3520 debug_leave(); 3521 return false; 3522 } 3523 3524 static bool 3525 should_warn_about_integer_conversion(const type_t *ntp, tspec_t nt, 3526 const tnode_t *otn, tspec_t ot) 3527 { 3528 3529 // XXX: The portable_rank_cmp aims at portable mode, independent of the 3530 // current platform, while can_represent acts on the actual type sizes 3531 // from the current platform. This mix is inconsistent, but anything 3532 // else would make the exact conditions too complicated to grasp. 3533 if (aflag > 0 && portable_rank_cmp(nt, ot) < 0) { 3534 if (ot == LONG || ot == ULONG 3535 || ot == LLONG || ot == ULLONG 3536 #ifdef INT128_SIZE 3537 || ot == INT128 || ot == UINT128 3538 #endif 3539 || aflag > 1) 3540 return !can_represent(ntp, otn); 3541 } 3542 return false; 3543 } 3544 3545 static void 3546 convert_integer_from_integer(op_t op, int arg, tspec_t nt, tspec_t ot, 3547 type_t *tp, tnode_t *tn) 3548 { 3549 3550 if (tn->tn_op == CON) 3551 return; 3552 3553 if (op == CVT) 3554 return; 3555 3556 if (Pflag && pflag && aflag > 0 && 3557 portable_rank_cmp(nt, ot) > 0 && 3558 is_uinteger(nt) != is_uinteger(ot)) { 3559 if (op == FARG) 3560 /* conversion to '%s' may sign-extend ... */ 3561 warning(297, type_name(tp), arg); 3562 else 3563 /* conversion to '%s' may sign-extend ... */ 3564 warning(131, type_name(tp)); 3565 } 3566 3567 if (Pflag && portable_rank_cmp(nt, ot) > 0 && 3568 (tn->tn_op == PLUS || tn->tn_op == MINUS || tn->tn_op == MULT || 3569 tn->tn_op == SHL)) { 3570 /* suggest cast from '%s' to '%s' on op '%s' to ... */ 3571 warning(324, type_name(gettyp(ot)), type_name(tp), 3572 op_name(tn->tn_op)); 3573 } 3574 3575 if (should_warn_about_integer_conversion(tp, nt, tn, ot)) { 3576 if (op == FARG) { 3577 /* conversion from '%s' to '%s' may lose ... */ 3578 warning(298, 3579 type_name(tn->tn_type), type_name(tp), arg); 3580 } else { 3581 /* conversion from '%s' to '%s' may lose accuracy */ 3582 warning(132, 3583 type_name(tn->tn_type), type_name(tp)); 3584 } 3585 } 3586 3587 if (any_query_enabled && is_uinteger(nt) != is_uinteger(ot)) 3588 /* implicit conversion changes sign from '%s' to '%s' */ 3589 query_message(3, type_name(tn->tn_type), type_name(tp)); 3590 } 3591 3592 static void 3593 convert_integer_from_pointer(op_t op, tspec_t nt, type_t *tp, tnode_t *tn) 3594 { 3595 3596 if (tn->tn_op == CON) 3597 return; 3598 if (op != CVT) 3599 return; /* We already got an error. */ 3600 if (portable_rank_cmp(nt, PTR) >= 0) 3601 return; 3602 3603 if (pflag && size_in_bits(nt) >= size_in_bits(PTR)) { 3604 /* conversion of pointer to '%s' may lose bits */ 3605 warning(134, type_name(tp)); 3606 } else { 3607 /* conversion of pointer to '%s' loses bits */ 3608 warning(133, type_name(tp)); 3609 } 3610 } 3611 3612 static bool 3613 struct_starts_with(const type_t *struct_tp, const type_t *member_tp) 3614 { 3615 3616 return struct_tp->u.sou->sou_first_member != NULL && 3617 types_compatible(struct_tp->u.sou->sou_first_member->s_type, 3618 member_tp, true, false, NULL); 3619 } 3620 3621 static bool 3622 is_byte_array(const type_t *tp) 3623 { 3624 3625 return tp->t_tspec == ARRAY && 3626 (tp->t_subt->t_tspec == CHAR || tp->t_subt->t_tspec == UCHAR); 3627 } 3628 3629 static bool 3630 union_contains(const type_t *utp, const type_t *mtp) 3631 { 3632 for (const sym_t *mem = utp->u.sou->sou_first_member; 3633 mem != NULL; mem = mem->s_next) { 3634 if (types_compatible(mem->s_type, mtp, true, false, NULL)) 3635 return true; 3636 } 3637 return false; 3638 } 3639 3640 static bool 3641 should_warn_about_pointer_cast(const type_t *nstp, tspec_t nst, 3642 const type_t *ostp, tspec_t ost) 3643 { 3644 3645 while (nst == ARRAY) 3646 nstp = nstp->t_subt, nst = nstp->t_tspec; 3647 while (ost == ARRAY) 3648 ostp = ostp->t_subt, ost = ostp->t_tspec; 3649 3650 if (nst == STRUCT && ost == STRUCT && 3651 (struct_starts_with(nstp, ostp) || 3652 struct_starts_with(ostp, nstp))) 3653 return false; 3654 3655 if (is_incomplete(nstp) || is_incomplete(ostp)) 3656 return false; 3657 3658 if (nst == CHAR || nst == UCHAR) 3659 return false; /* for the sake of traditional C code */ 3660 if (ost == CHAR || ost == UCHAR) 3661 return false; /* for the sake of traditional C code */ 3662 3663 /* Allow cast between pointers to sockaddr variants. */ 3664 if (nst == STRUCT && ost == STRUCT) { 3665 const sym_t *nmem = nstp->u.sou->sou_first_member; 3666 const sym_t *omem = ostp->u.sou->sou_first_member; 3667 while (nmem != NULL && omem != NULL && 3668 types_compatible(nmem->s_type, omem->s_type, 3669 true, false, NULL)) 3670 nmem = nmem->s_next, omem = omem->s_next; 3671 if (nmem != NULL && is_byte_array(nmem->s_type)) 3672 return false; 3673 if (omem != NULL && is_byte_array(omem->s_type)) 3674 return false; 3675 if (nmem == NULL && omem == NULL) 3676 return false; 3677 } 3678 3679 if (nst == UNION || ost == UNION) { 3680 const type_t *union_tp = nst == UNION ? nstp : ostp; 3681 const type_t *other_tp = nst == UNION ? ostp : nstp; 3682 if (union_contains(union_tp, other_tp)) 3683 return false; 3684 } 3685 3686 if (is_struct_or_union(nst) && is_struct_or_union(ost)) 3687 return nstp->u.sou != ostp->u.sou; 3688 3689 enum rank_kind rk1 = type_properties(nst)->tt_rank_kind; 3690 enum rank_kind rk2 = type_properties(ost)->tt_rank_kind; 3691 if (rk1 != rk2 || rk1 == RK_NONE) 3692 return true; 3693 3694 return portable_rank_cmp(nst, ost) != 0; 3695 } 3696 3697 static void 3698 convert_pointer_from_pointer(type_t *ntp, tnode_t *tn) 3699 { 3700 const type_t *nstp = ntp->t_subt; 3701 const type_t *otp = tn->tn_type; 3702 const type_t *ostp = otp->t_subt; 3703 tspec_t nst = nstp->t_tspec; 3704 tspec_t ost = ostp->t_tspec; 3705 3706 if (nst == VOID || ost == VOID) { 3707 /* TODO: C99 behaves like C90 here. */ 3708 if (!allow_trad && !allow_c99 && (nst == FUNC || ost == FUNC)) { 3709 const char *nts, *ots; 3710 /* null pointers are already handled in convert() */ 3711 *(nst == FUNC ? &nts : &ots) = "function pointer"; 3712 *(nst == VOID ? &nts : &ots) = "'void *'"; 3713 /* conversion of %s to %s requires a cast */ 3714 warning(303, ots, nts); 3715 } 3716 return; 3717 } 3718 if (nst == FUNC && ost == FUNC) 3719 return; 3720 if (nst == FUNC || ost == FUNC) { 3721 /* converting '%s' to '%s' is questionable */ 3722 warning(229, type_name(otp), type_name(ntp)); 3723 return; 3724 } 3725 3726 if (hflag && alignment(nstp) > alignment(ostp) && 3727 ost != CHAR && ost != UCHAR && 3728 !is_incomplete(ostp) && 3729 !(nst == UNION && union_contains(nstp, ostp))) { 3730 /* converting '%s' to '%s' increases alignment ... */ 3731 warning(135, type_name(otp), type_name(ntp), 3732 alignment(ostp), alignment(nstp)); 3733 } 3734 3735 if (cflag && should_warn_about_pointer_cast(nstp, nst, ostp, ost)) { 3736 /* pointer cast from '%s' to unrelated '%s' */ 3737 warning(247, type_name(ostp), type_name(nstp)); 3738 } 3739 } 3740 3741 /* 3742 * Insert a conversion operator, which converts the type of the node 3743 * to another given type. 3744 * 3745 * Possible values for 'op': 3746 * CVT a cast-expression 3747 * binary integer promotion for one of the operands, or a usual 3748 * arithmetic conversion 3749 * binary plain or compound assignments to bit-fields 3750 * FARG 'arg' is the number of the parameter (used for warnings) 3751 * NOOP several other implicit conversions 3752 * ... 3753 */ 3754 tnode_t * 3755 convert(op_t op, int arg, type_t *tp, tnode_t *tn) 3756 { 3757 tspec_t nt = tp->t_tspec; 3758 tspec_t ot = tn->tn_type->t_tspec; 3759 3760 if (allow_trad && allow_c90 && op == FARG) 3761 check_prototype_conversion(arg, nt, ot, tp, tn); 3762 3763 if (nt == BOOL) { 3764 /* No further checks. */ 3765 3766 } else if (is_integer(nt)) { 3767 if (ot == BOOL) { 3768 /* No further checks. */ 3769 } else if (is_integer(ot)) 3770 convert_integer_from_integer(op, arg, nt, ot, tp, tn); 3771 else if (is_floating(ot)) 3772 convert_integer_from_floating(op, arg, tp, tn); 3773 else if (ot == PTR) 3774 convert_integer_from_pointer(op, nt, tp, tn); 3775 3776 } else if (is_floating(nt)) { 3777 if (is_integer(ot) && op != CVT) { 3778 /* implicit conversion from integer '%s' to ... */ 3779 query_message(19, 3780 type_name(tn->tn_type), type_name(tp)); 3781 } 3782 3783 } else if (nt == PTR) { 3784 if (is_null_pointer(tn)) { 3785 /* a null pointer may be assigned to any pointer. */ 3786 } else if (ot == PTR && op == CVT) 3787 convert_pointer_from_pointer(tp, tn); 3788 } 3789 3790 tnode_t *ntn = expr_alloc_tnode(); 3791 ntn->tn_op = CVT; 3792 ntn->tn_type = tp; 3793 ntn->tn_cast = op == CVT; 3794 ntn->tn_sys |= tn->tn_sys; 3795 ntn->u.ops.right = NULL; 3796 if (tn->tn_op != CON || nt == VOID) { 3797 ntn->u.ops.left = tn; 3798 } else { 3799 ntn->tn_op = CON; 3800 convert_constant(op, arg, ntn->tn_type, &ntn->u.value, 3801 &tn->u.value); 3802 } 3803 3804 return ntn; 3805 } 3806 3807 static void 3808 convert_constant_from_floating(op_t op, int arg, const type_t *ntp, 3809 tspec_t nt, val_t *nv, val_t *ov) 3810 { 3811 long double max = 0.0, min = 0.0; 3812 3813 switch (nt) { 3814 case CHAR: 3815 max = TARG_CHAR_MAX; min = TARG_CHAR_MIN; break; 3816 case UCHAR: 3817 max = TARG_UCHAR_MAX; min = 0; break; 3818 case SCHAR: 3819 max = TARG_SCHAR_MAX; min = TARG_SCHAR_MIN; break; 3820 case SHORT: 3821 max = TARG_SHRT_MAX; min = TARG_SHRT_MIN; break; 3822 case USHORT: 3823 max = TARG_USHRT_MAX; min = 0; break; 3824 case ENUM: 3825 case INT: 3826 max = TARG_INT_MAX; min = TARG_INT_MIN; break; 3827 case UINT: 3828 max = TARG_UINT_MAX; min = 0; break; 3829 case LONG: 3830 max = TARG_LONG_MAX; min = TARG_LONG_MIN; break; 3831 case ULONG: 3832 max = TARG_ULONG_MAX; min = 0; break; 3833 case LLONG: 3834 max = LLONG_MAX; min = LLONG_MIN; break; 3835 case ULLONG: 3836 max = ULLONG_MAX; min = 0; break; 3837 case FLOAT: 3838 case FCOMPLEX: 3839 max = FLT_MAX; min = -FLT_MAX; break; 3840 case DOUBLE: 3841 case DCOMPLEX: 3842 max = DBL_MAX; min = -DBL_MAX; break; 3843 case LDOUBLE: 3844 case LCOMPLEX: 3845 /* LINTED 248; see floating_error_value. */ 3846 max = LDBL_MAX; min = -max; break; 3847 default: 3848 lint_assert(/*CONSTCOND*/false); 3849 } 3850 if (ov->u.floating > max || ov->u.floating < min) { 3851 lint_assert(nt != LDOUBLE); 3852 const char *ot_name = type_name(gettyp(ov->v_tspec)); 3853 const char *nt_name = type_name(ntp); 3854 if (is_integer(nt)) 3855 goto after_warning; 3856 if (op == FARG) 3857 /* conversion of '%s' to '%s' is out of range, ... */ 3858 warning(295, ot_name, nt_name, arg); 3859 else 3860 /* conversion of '%s' to '%s' is out of range */ 3861 warning(119, ot_name, nt_name); 3862 after_warning: 3863 ov->u.floating = ov->u.floating > 0 ? max : min; 3864 } 3865 3866 if (nt == FLOAT || nt == FCOMPLEX) 3867 nv->u.floating = (float)ov->u.floating; 3868 else if (nt == DOUBLE || nt == DCOMPLEX) 3869 nv->u.floating = (double)ov->u.floating; 3870 else if (nt == LDOUBLE || nt == LCOMPLEX) 3871 nv->u.floating = ov->u.floating; 3872 else 3873 nv->u.integer = (int64_t)ov->u.floating; 3874 } 3875 3876 static bool 3877 convert_constant_to_floating(tspec_t nt, val_t *nv, 3878 tspec_t ot, const val_t *v) 3879 { 3880 if (nt == FLOAT) { 3881 nv->u.floating = (ot == PTR || is_uinteger(ot)) ? 3882 (float)(uint64_t)v->u.integer : (float)v->u.integer; 3883 } else if (nt == DOUBLE) { 3884 nv->u.floating = (ot == PTR || is_uinteger(ot)) ? 3885 (double)(uint64_t)v->u.integer : (double)v->u.integer; 3886 } else if (nt == LDOUBLE) { 3887 nv->u.floating = (ot == PTR || is_uinteger(ot)) 3888 ? (long double)(uint64_t)v->u.integer 3889 : (long double)v->u.integer; 3890 } else 3891 return false; 3892 return true; 3893 } 3894 3895 /* 3896 * Print a warning if bits which were set are lost due to the conversion. 3897 * This can happen with operator ORASS only. 3898 */ 3899 static void 3900 convert_constant_check_range_bitor(size_t nsz, size_t osz, const val_t *v, 3901 uint64_t xmask, op_t op) 3902 { 3903 if (nsz < osz && (v->u.integer & xmask) != 0) 3904 /* constant truncated by conversion, op '%s' */ 3905 warning(306, op_name(op)); 3906 } 3907 3908 static void 3909 convert_constant_check_range_bitand(size_t nsz, size_t osz, 3910 uint64_t xmask, const val_t *nv, 3911 tspec_t ot, const val_t *v, 3912 const type_t *tp, op_t op) 3913 { 3914 if (nsz > osz && 3915 (nv->u.integer & bit((unsigned int)(osz - 1))) != 0 && 3916 (nv->u.integer & xmask) != xmask) { 3917 /* extra bits set to 0 in conversion of '%s' to '%s', ... */ 3918 warning(309, type_name(gettyp(ot)), 3919 type_name(tp), op_name(op)); 3920 } else if (nsz < osz && 3921 (v->u.integer & xmask) != xmask && 3922 (v->u.integer & xmask) != 0) 3923 /* constant truncated by conversion, op '%s' */ 3924 warning(306, op_name(op)); 3925 } 3926 3927 static void 3928 convert_constant_check_range_signed(op_t op, int arg, 3929 const type_t *ntp, int64_t ov) 3930 { 3931 if (op == ASSIGN) 3932 /* assignment of negative constant %lld to unsigned ... */ 3933 warning(164, (long long)ov, type_name(ntp)); 3934 else if (op == INIT) 3935 /* initialization of unsigned type '%s' with negative ... */ 3936 warning(221, type_name(ntp), (long long)ov); 3937 else if (op == FARG) 3938 /* conversion of negative constant %lld to unsigned ... */ 3939 warning(296, (long long)ov, type_name(ntp), arg); 3940 else if (modtab[op].m_comparison) { 3941 /* handled by check_integer_comparison() */ 3942 } else 3943 /* conversion of negative constant %lld to unsigned ... */ 3944 warning(222, (long long)ov, type_name(ntp)); 3945 } 3946 3947 /* 3948 * Loss of significant bit(s). All truncated bits of unsigned types or all 3949 * truncated bits plus the msb of the target for signed types are considered 3950 * to be significant bits. Loss of significant bits means that at least one 3951 * of the bits was set in an unsigned type or that at least one but not all 3952 * of the bits was set in a signed type. Loss of significant bits means that 3953 * it is not possible, also not with necessary casts, to convert back to the 3954 * original type. An example for a necessary cast is: 3955 * char c; int i; c = 128; 3956 * i = c; ** yields -128 ** 3957 * i = (unsigned char)c; ** yields 128 ** 3958 */ 3959 static void 3960 warn_constant_check_range_truncated(op_t op, int arg, const type_t *tp, 3961 tspec_t ot) 3962 { 3963 if (op == ASSIGN && tp->t_bitfield) 3964 /* precision lost in bit-field assignment */ 3965 warning(166); 3966 else if (op == ASSIGN) 3967 /* constant truncated by assignment */ 3968 warning(165); 3969 else if (op == INIT && tp->t_bitfield) 3970 /* bit-field initializer does not fit */ 3971 warning(180); 3972 else if (op == INIT) 3973 /* initializer does not fit */ 3974 warning(178); 3975 else if (op == CASE) 3976 /* case label affected by conversion */ 3977 warning(196); 3978 else if (op == FARG) 3979 /* conversion of '%s' to '%s' is out of range, arg #%d */ 3980 warning(295, type_name(gettyp(ot)), type_name(tp), arg); 3981 else 3982 /* conversion of '%s' to '%s' is out of range */ 3983 warning(119, type_name(gettyp(ot)), type_name(tp)); 3984 } 3985 3986 static void 3987 warn_constant_check_range_loss(op_t op, int arg, const type_t *tp, 3988 tspec_t ot) 3989 { 3990 if (op == ASSIGN && tp->t_bitfield) 3991 /* precision lost in bit-field assignment */ 3992 warning(166); 3993 else if (op == INIT && tp->t_bitfield) 3994 /* bit-field initializer out of range */ 3995 warning(11); 3996 else if (op == CASE) 3997 /* case label affected by conversion */ 3998 warning(196); 3999 else if (op == FARG) 4000 /* conversion of '%s' to '%s' is out of range, arg #%d */ 4001 warning(295, type_name(gettyp(ot)), type_name(tp), arg); 4002 else 4003 /* conversion of '%s' to '%s' is out of range */ 4004 warning(119, type_name(gettyp(ot)), type_name(tp)); 4005 } 4006 4007 static void 4008 convert_constant_check_range(tspec_t ot, const type_t *tp, tspec_t nt, 4009 op_t op, int arg, const val_t *v, val_t *nv) 4010 { 4011 unsigned int obitsz, nbitsz; 4012 uint64_t xmask, xmsk1; 4013 4014 obitsz = size_in_bits(ot); 4015 nbitsz = tp->t_bitfield ? tp->t_bit_field_width : size_in_bits(nt); 4016 xmask = value_bits(nbitsz) ^ value_bits(obitsz); 4017 xmsk1 = value_bits(nbitsz) ^ value_bits(obitsz - 1); 4018 if (op == ORASS || op == BITOR || op == BITXOR) { 4019 convert_constant_check_range_bitor( 4020 nbitsz, obitsz, v, xmask, op); 4021 } else if (op == ANDASS || op == BITAND) { 4022 convert_constant_check_range_bitand( 4023 nbitsz, obitsz, xmask, nv, ot, v, tp, op); 4024 } else if (nt != PTR && is_uinteger(nt) && 4025 ot != PTR && !is_uinteger(ot) && 4026 v->u.integer < 0) 4027 convert_constant_check_range_signed(op, arg, 4028 tp, v->u.integer); 4029 else if (nv->u.integer != v->u.integer && nbitsz <= obitsz && 4030 (v->u.integer & xmask) != 0 && 4031 (is_uinteger(ot) || (v->u.integer & xmsk1) != xmsk1)) 4032 warn_constant_check_range_truncated(op, arg, tp, ot); 4033 else if (nv->u.integer != v->u.integer) 4034 warn_constant_check_range_loss(op, arg, tp, ot); 4035 } 4036 4037 /* Converts a typed constant to a constant of another type. */ 4038 void 4039 convert_constant(op_t op, int arg, const type_t *ntp, val_t *nv, val_t *ov) 4040 { 4041 /* 4042 * TODO: make 'ov' const; the name of this function does not suggest 4043 * that it modifies 'ov'. 4044 */ 4045 tspec_t ot = ov->v_tspec; 4046 tspec_t nt = nv->v_tspec = ntp->t_tspec; 4047 bool range_check = false; 4048 4049 if (nt == BOOL) { /* C99 6.3.1.2 */ 4050 nv->v_unsigned_since_c90 = false; 4051 nv->u.integer = is_nonzero_val(ov) ? 1 : 0; 4052 return; 4053 } 4054 4055 if (ot == FLOAT || ot == DOUBLE || ot == LDOUBLE) 4056 convert_constant_from_floating(op, arg, ntp, nt, nv, ov); 4057 else if (!convert_constant_to_floating(nt, nv, ot, ov)) { 4058 range_check = true; /* Check for lost precision. */ 4059 nv->u.integer = ov->u.integer; 4060 } 4061 4062 if (allow_trad && allow_c90 && ov->v_unsigned_since_c90 && 4063 (is_floating(nt) || ( 4064 (is_integer(nt) && !is_uinteger(nt) && 4065 portable_rank_cmp(nt, ot) > 0)))) { 4066 /* C90 treats constant as unsigned */ 4067 warning(157); 4068 ov->v_unsigned_since_c90 = false; 4069 } 4070 4071 if (is_integer(nt)) { 4072 unsigned int size = ntp->t_bitfield 4073 ? ntp->t_bit_field_width : size_in_bits(nt); 4074 nv->u.integer = convert_integer(nv->u.integer, nt, size); 4075 } 4076 4077 if (range_check && op != CVT) 4078 convert_constant_check_range(ot, ntp, nt, op, arg, ov, nv); 4079 } 4080 4081 tnode_t * 4082 build_sizeof(const type_t *tp) 4083 { 4084 unsigned int size_in_bytes = type_size_in_bits(tp) / CHAR_SIZE; 4085 tnode_t *tn = build_integer_constant(SIZEOF_TSPEC, size_in_bytes); 4086 tn->tn_system_dependent = true; 4087 debug_step("build_sizeof '%s' = %u", type_name(tp), size_in_bytes); 4088 return tn; 4089 } 4090 4091 tnode_t * 4092 build_offsetof(const type_t *tp, designation dn) 4093 { 4094 unsigned int offset_in_bits = 0; 4095 4096 if (!is_struct_or_union(tp->t_tspec)) { 4097 /* unacceptable operand of '%s' */ 4098 error(111, "offsetof"); 4099 goto proceed; 4100 } 4101 for (size_t i = 0; i < dn.dn_len; i++) { 4102 const designator *dr = dn.dn_items + i; 4103 if (dr->dr_kind == DK_SUBSCRIPT) { 4104 if (tp->t_tspec != ARRAY) 4105 goto proceed; /* silent error */ 4106 tp = tp->t_subt; 4107 offset_in_bits += (unsigned) dr->dr_subscript 4108 * type_size_in_bits(tp); 4109 } else { 4110 if (!is_struct_or_union(tp->t_tspec)) 4111 goto proceed; /* silent error */ 4112 const char *name = dr->dr_member->s_name; 4113 sym_t *mem = find_member(tp->u.sou, name); 4114 if (mem == NULL) { 4115 /* type '%s' does not have member '%s' */ 4116 error(101, name, type_name(tp)); 4117 goto proceed; 4118 } 4119 tp = mem->s_type; 4120 offset_in_bits += mem->u.s_member.sm_offset_in_bits; 4121 } 4122 } 4123 free(dn.dn_items); 4124 4125 proceed:; 4126 unsigned int offset_in_bytes = offset_in_bits / CHAR_SIZE; 4127 tnode_t *tn = build_integer_constant(SIZEOF_TSPEC, offset_in_bytes); 4128 tn->tn_system_dependent = true; 4129 return tn; 4130 } 4131 4132 unsigned int 4133 type_size_in_bits(const type_t *tp) 4134 { 4135 4136 unsigned int elem = 1; 4137 bool flex = false; 4138 lint_assert(tp != NULL); 4139 while (tp->t_tspec == ARRAY) { 4140 flex = true; /* allow c99 flex arrays [] [0] */ 4141 elem *= tp->u.dimension; 4142 tp = tp->t_subt; 4143 } 4144 if (elem == 0 && !flex) { 4145 /* cannot take size/alignment of incomplete type */ 4146 error(143); 4147 elem = 1; 4148 } 4149 4150 unsigned int elsz; 4151 switch (tp->t_tspec) { 4152 case VOID: 4153 /* cannot take size/alignment of void */ 4154 error(146); 4155 elsz = 1; 4156 break; 4157 case FUNC: 4158 /* cannot take size/alignment of function type '%s' */ 4159 error(144, type_name(tp)); 4160 elsz = 1; 4161 break; 4162 case STRUCT: 4163 case UNION: 4164 if (is_incomplete(tp)) { 4165 /* cannot take size/alignment of incomplete type */ 4166 error(143); 4167 elsz = 1; 4168 } else 4169 elsz = tp->u.sou->sou_size_in_bits; 4170 break; 4171 case ENUM: 4172 if (is_incomplete(tp)) { 4173 /* cannot take size/alignment of incomplete type */ 4174 warning(143); 4175 } 4176 /* FALLTHROUGH */ 4177 default: 4178 if (tp->t_bitfield) 4179 /* cannot take size/alignment of bit-field */ 4180 error(145); 4181 elsz = size_in_bits(tp->t_tspec); 4182 lint_assert(elsz > 0); 4183 break; 4184 } 4185 4186 return elem * elsz; 4187 } 4188 4189 /* C11 6.5.3.4, GCC */ 4190 tnode_t * 4191 build_alignof(const type_t *tp) 4192 { 4193 if (tp->t_tspec == FUNC) { 4194 /* cannot take size/alignment of function type '%s' */ 4195 error(144, type_name(tp)); 4196 return NULL; 4197 } 4198 if (tp->t_tspec == VOID) { 4199 /* cannot take size/alignment of void */ 4200 error(146); 4201 return NULL; 4202 } 4203 if (is_incomplete(tp)) { 4204 /* cannot take size/alignment of incomplete type */ 4205 error(143); 4206 return NULL; 4207 } 4208 if (tp->t_bitfield) { 4209 /* cannot take size/alignment of bit-field */ 4210 error(145); 4211 return NULL; 4212 } 4213 return build_integer_constant(SIZEOF_TSPEC, (int64_t)alignment(tp)); 4214 } 4215 4216 static tnode_t * 4217 cast_to_union(tnode_t *otn, bool sys, type_t *ntp) 4218 { 4219 4220 if (!allow_gcc) { 4221 /* union cast is a GCC extension */ 4222 error(328); 4223 return NULL; 4224 } 4225 4226 for (const sym_t *m = ntp->u.sou->sou_first_member; 4227 m != NULL; m = m->s_next) { 4228 if (types_compatible(m->s_type, otn->tn_type, 4229 false, false, NULL)) { 4230 tnode_t *ntn = build_op(CVT, sys, ntp, otn, NULL); 4231 ntn->tn_cast = true; 4232 return ntn; 4233 } 4234 } 4235 4236 /* type '%s' is not a member of '%s' */ 4237 error(329, type_name(otn->tn_type), type_name(ntp)); 4238 return NULL; 4239 } 4240 4241 // In GCC mode, allow 'nullptr + offset' as a constant expression. 4242 static tnode_t * 4243 null_pointer_offset(tnode_t *tn) 4244 { 4245 uint64_t off = 0; 4246 const tnode_t *n = tn; 4247 while ((n->tn_op == PLUS || n->tn_op == MINUS) 4248 && is_integer(n->u.ops.right->tn_type->t_tspec)) { 4249 off += (uint64_t)n->u.ops.right->u.value.u.integer; 4250 n = n->u.ops.left; 4251 } 4252 if (n->tn_type->t_tspec == PTR 4253 && n->tn_op == ADDR 4254 && n->u.ops.left->tn_op == INDIR 4255 && n->u.ops.left->u.ops.left->tn_op == CON 4256 && n->u.ops.left->u.ops.left->tn_type->t_tspec == PTR) { 4257 off += (uint64_t)n->u.ops.left->u.ops.left->u.value.u.integer; 4258 return build_integer_constant(SIZEOF_TSPEC, (int64_t)off); 4259 } 4260 return tn; 4261 } 4262 4263 tnode_t * 4264 cast(tnode_t *tn, bool sys, type_t *tp) 4265 { 4266 4267 if (tn == NULL) 4268 return NULL; 4269 4270 tn = cconv(tn); 4271 4272 lint_assert(tp != NULL); 4273 tspec_t nt = tp->t_tspec; 4274 tspec_t ot = tn->tn_type->t_tspec; 4275 4276 if (nt == VOID) { 4277 /* 4278 * C90 6.3.4, C99 6.5.4p2 and C11 6.5.4p2 allow any type to be 4279 * cast to void. The only other allowed casts are from a 4280 * scalar type to a scalar type. 4281 */ 4282 } else if (nt == UNION) 4283 return cast_to_union(tn, sys, tp); 4284 else if (nt == STRUCT || nt == ARRAY || nt == FUNC) { 4285 /* Casting to a struct is an undocumented GCC extension. */ 4286 if (!(allow_gcc && nt == STRUCT)) 4287 goto invalid_cast; 4288 } else if (is_struct_or_union(ot)) 4289 goto invalid_cast; 4290 else if (ot == VOID) { 4291 /* improper cast of void expression */ 4292 error(148); 4293 return NULL; 4294 } else if (is_integer(nt) && is_scalar(ot)) { 4295 tn = null_pointer_offset(tn); 4296 } else if (is_floating(nt) && is_arithmetic(ot)) { 4297 /* ok */ 4298 } else if (nt == PTR && is_integer(ot)) { 4299 /* ok */ 4300 } else if (nt == PTR && ot == PTR) { 4301 if (!tp->t_subt->t_const && tn->tn_type->t_subt->t_const) { 4302 if (hflag) 4303 /* cast discards 'const' from type '%s' */ 4304 warning(275, type_name(tn->tn_type)); 4305 } 4306 } else 4307 goto invalid_cast; 4308 4309 if (any_query_enabled 4310 && types_compatible(tp, tn->tn_type, false, false, NULL)) 4311 /* no-op cast from '%s' to '%s' */ 4312 query_message(6, type_name(tn->tn_type), type_name(tp)); 4313 4314 tn = convert(CVT, 0, tp, tn); 4315 tn->tn_cast = true; 4316 tn->tn_sys = sys; 4317 4318 return tn; 4319 4320 invalid_cast: 4321 /* invalid cast from '%s' to '%s' */ 4322 error(147, type_name(tn->tn_type), type_name(tp)); 4323 return NULL; 4324 } 4325 4326 void 4327 add_function_argument(function_call *call, tnode_t *arg) 4328 { 4329 /* 4330 * If there was a serious error in the expression for the argument, 4331 * create a dummy argument so the positions of the remaining arguments 4332 * will not change. 4333 */ 4334 if (arg == NULL) 4335 arg = build_integer_constant(INT, 0); 4336 4337 if (call->args_len >= call->args_cap) { 4338 call->args_cap += 8; 4339 tnode_t **new_args = expr_zero_alloc( 4340 call->args_cap * sizeof(*call->args), "tnode*[]"); 4341 if (call->args_len > 0) 4342 memcpy(new_args, call->args, 4343 call->args_len * sizeof(*call->args)); 4344 call->args = new_args; 4345 } 4346 call->args[call->args_len++] = arg; 4347 } 4348 4349 /* 4350 * Compare the type of an argument with the corresponding type of a 4351 * prototype parameter. If it is a valid combination, but both types 4352 * are not the same, insert a conversion to convert the argument into 4353 * the type of the parameter. 4354 */ 4355 static tnode_t * 4356 check_prototype_argument( 4357 int n, /* pos of arg */ 4358 type_t *tp, /* expected type (from prototype) */ 4359 tnode_t *tn) /* argument */ 4360 { 4361 tnode_t *ln = xcalloc(1, sizeof(*ln)); 4362 ln->tn_type = expr_unqualified_type(tp); 4363 ln->tn_lvalue = true; 4364 if (typeok(FARG, n, ln, tn)) { 4365 bool dowarn; 4366 if (!types_compatible(tp, tn->tn_type, 4367 true, false, (dowarn = false, &dowarn)) || dowarn) 4368 tn = convert(FARG, n, tp, tn); 4369 } 4370 free(ln); 4371 return tn; 4372 } 4373 4374 /* 4375 * Check types of all function arguments and insert conversions, 4376 * if necessary. 4377 */ 4378 static void 4379 check_function_arguments(const function_call *call) 4380 { 4381 type_t *ftp = call->func->tn_type->t_subt; 4382 4383 /* get # of parameters in the prototype */ 4384 int npar = 0; 4385 for (const sym_t *p = ftp->u.params; p != NULL; p = p->s_next) 4386 npar++; 4387 4388 int narg = (int)call->args_len; 4389 4390 const sym_t *param = ftp->u.params; 4391 if (ftp->t_proto && npar != narg && !(ftp->t_vararg && npar < narg)) { 4392 /* argument mismatch: %d %s passed, %d expected */ 4393 error(150, narg, narg != 1 ? "arguments" : "argument", npar); 4394 param = NULL; 4395 } 4396 4397 for (int i = 0; i < narg; i++) { 4398 tnode_t *arg = call->args[i]; 4399 4400 /* some things which are always not allowed */ 4401 tspec_t at = arg->tn_type->t_tspec; 4402 if (at == VOID) { 4403 /* void expressions may not be arguments, arg #%d */ 4404 error(151, i + 1); 4405 return; 4406 } 4407 if (is_struct_or_union(at) && is_incomplete(arg->tn_type)) { 4408 /* argument cannot have unknown size, arg #%d */ 4409 error(152, i + 1); 4410 return; 4411 } 4412 if (is_integer(at) && 4413 arg->tn_type->t_is_enum && 4414 is_incomplete(arg->tn_type)) { 4415 /* argument cannot have unknown size, arg #%d */ 4416 warning(152, i + 1); 4417 } 4418 4419 arg = cconv(arg); 4420 call->args[i] = arg; 4421 4422 arg = param != NULL 4423 ? check_prototype_argument(i + 1, param->s_type, arg) 4424 : promote(NOOP, true, arg); 4425 call->args[i] = arg; 4426 4427 if (param != NULL) 4428 param = param->s_next; 4429 } 4430 } 4431 4432 tnode_t * 4433 build_function_call(tnode_t *func, bool sys, function_call *call) 4434 { 4435 4436 if (func == NULL) 4437 return NULL; 4438 4439 call->func = func; 4440 check_ctype_function_call(call); 4441 4442 func = cconv(func); 4443 call->func = func; 4444 4445 if (func->tn_type->t_tspec != PTR || 4446 func->tn_type->t_subt->t_tspec != FUNC) { 4447 /* cannot call '%s', must be a function */ 4448 error(149, type_name(func->tn_type)); 4449 return NULL; 4450 } 4451 4452 check_function_arguments(call); 4453 4454 tnode_t *ntn = expr_alloc_tnode(); 4455 ntn->tn_op = CALL; 4456 ntn->tn_type = func->tn_type->t_subt->t_subt; 4457 ntn->tn_sys = sys; 4458 ntn->u.call = call; 4459 return ntn; 4460 } 4461 4462 /* 4463 * Return the value of an integral constant expression. 4464 * If the expression is not constant or its type is not an integer 4465 * type, an error message is printed. 4466 */ 4467 val_t * 4468 integer_constant(tnode_t *tn, bool required) 4469 { 4470 4471 if (tn != NULL) 4472 tn = cconv(tn); 4473 if (tn != NULL) 4474 tn = promote(NOOP, false, tn); 4475 4476 val_t *v = xcalloc(1, sizeof(*v)); 4477 4478 if (tn == NULL) { 4479 lint_assert(seen_error); 4480 debug_step("constant node is null; returning 1 instead"); 4481 v->v_tspec = INT; 4482 v->u.integer = 1; 4483 return v; 4484 } 4485 4486 v->v_tspec = tn->tn_type->t_tspec; 4487 4488 if (tn->tn_op == CON) { 4489 lint_assert(tn->tn_type->t_tspec == tn->u.value.v_tspec); 4490 if (is_integer(tn->u.value.v_tspec)) { 4491 v->v_unsigned_since_c90 = 4492 tn->u.value.v_unsigned_since_c90; 4493 v->u.integer = tn->u.value.u.integer; 4494 return v; 4495 } 4496 v->u.integer = (int64_t)tn->u.value.u.floating; 4497 } else 4498 v->u.integer = 1; 4499 4500 if (required) 4501 /* integral constant expression expected */ 4502 error(55); 4503 else 4504 /* variable array dimension is a C99/GCC extension */ 4505 c99ism(318); 4506 4507 if (!is_integer(v->v_tspec)) 4508 v->v_tspec = INT; 4509 4510 return v; 4511 } 4512 4513 static bool 4514 is_constcond_false(const tnode_t *tn, tspec_t t) 4515 { 4516 return (t == BOOL || t == INT) && 4517 tn->tn_op == CON && tn->u.value.u.integer == 0; 4518 } 4519 4520 /* 4521 * Perform some tests on expressions which can't be done in build_binary() 4522 * and functions called by build_binary(). These tests must be done here 4523 * because we need some information about the context in which the operations 4524 * are performed. 4525 * After all tests are performed and dofreeblk is true, expr() frees the 4526 * memory which is used for the expression. 4527 */ 4528 void 4529 expr(tnode_t *tn, bool vctx, bool cond, bool dofreeblk, bool is_do_while, 4530 const char *stmt_kind) 4531 { 4532 4533 if (tn == NULL) { /* in case of errors */ 4534 expr_free_all(); 4535 return; 4536 } 4537 4538 /* expr() is also called in global initializations */ 4539 if (dcs->d_kind != DLK_EXTERN && !is_do_while) 4540 check_statement_reachable(stmt_kind); 4541 4542 check_expr_misc(tn, vctx, cond, !cond, false, false, false); 4543 if (tn->tn_op == ASSIGN && !tn->tn_parenthesized) { 4544 if (hflag && cond) 4545 /* assignment in conditional context */ 4546 warning(159); 4547 } else if (tn->tn_op == CON) { 4548 if (hflag && cond && !suppress_constcond && 4549 !tn->tn_system_dependent && 4550 !(is_do_while && 4551 is_constcond_false(tn, tn->tn_type->t_tspec))) 4552 /* constant in conditional context */ 4553 warning(161); 4554 } 4555 if (!modtab[tn->tn_op].m_has_side_effect) { 4556 /* 4557 * for left operands of COMMA this warning is already printed 4558 */ 4559 if (tn->tn_op != COMMA && !vctx && !cond) 4560 check_null_effect(tn); 4561 } 4562 debug_node(tn); 4563 4564 if (dofreeblk) 4565 expr_free_all(); 4566 } 4567 4568 /* If the expression has the form '*(arr + idx)', check the array index. */ 4569 static void 4570 check_array_index(const tnode_t *indir, bool taking_address) 4571 { 4572 const tnode_t *plus, *arr, *idx; 4573 4574 if (indir->tn_op == INDIR 4575 && (plus = indir->u.ops.left, plus->tn_op == PLUS) 4576 && plus->u.ops.left->tn_op == ADDR 4577 && (arr = plus->u.ops.left->u.ops.left, true) 4578 && (arr->tn_op == STRING || arr->tn_op == NAME) 4579 && arr->tn_type->t_tspec == ARRAY 4580 && (idx = plus->u.ops.right, idx->tn_op == CON) 4581 && (!is_incomplete(arr->tn_type) || idx->u.value.u.integer < 0)) 4582 goto proceed; 4583 return; 4584 4585 proceed:; 4586 int elsz = length_in_bits(arr->tn_type->t_subt, NULL); 4587 if (elsz == 0) 4588 return; 4589 elsz /= CHAR_SIZE; 4590 4591 /* Change the unit of the index from bytes to element size. */ 4592 int64_t con = is_uinteger(idx->tn_type->t_tspec) 4593 ? (int64_t)((uint64_t)idx->u.value.u.integer / elsz) 4594 : idx->u.value.u.integer / elsz; 4595 4596 int dim = arr->tn_type->u.dimension + (taking_address ? 1 : 0); 4597 4598 if (!is_uinteger(idx->tn_type->t_tspec) && con < 0) 4599 /* array subscript %jd cannot be negative */ 4600 warning(167, (intmax_t)con); 4601 else if (dim > 0 && (uint64_t)con >= (uint64_t)dim) 4602 /* array subscript %ju cannot be > %d */ 4603 warning(168, (uintmax_t)con, dim - 1); 4604 } 4605 4606 static void 4607 check_expr_addr(const tnode_t *ln, bool szof, bool fcall) 4608 { 4609 /* XXX: Taking warn_about_unreachable into account here feels wrong. */ 4610 if (ln->tn_op == NAME && (reached || !warn_about_unreachable)) { 4611 if (!szof) 4612 mark_as_set(ln->u.sym); 4613 mark_as_used(ln->u.sym, fcall, szof); 4614 } 4615 check_array_index(ln, true); 4616 } 4617 4618 /* 4619 * If there is an asm statement in one of the compound statements around, 4620 * there may be other side effects, so don't warn. 4621 */ 4622 static bool 4623 is_asm_around(void) 4624 { 4625 for (decl_level *dl = dcs; dl != NULL; dl = dl->d_enclosing) 4626 if (dl->d_asm) 4627 return true; 4628 return false; 4629 } 4630 4631 static void 4632 check_expr_side_effect(const tnode_t *ln, bool szof) 4633 { 4634 4635 /* XXX: Taking warn_about_unreachable into account here feels wrong. */ 4636 if (ln->tn_op == NAME && (reached || !warn_about_unreachable)) { 4637 scl_t sc = ln->u.sym->s_scl; 4638 if (sc != EXTERN && sc != STATIC && 4639 !ln->u.sym->s_set && !szof && !is_asm_around()) { 4640 /* '%s' may be used before set */ 4641 warning(158, ln->u.sym->s_name); 4642 mark_as_set(ln->u.sym); 4643 } 4644 mark_as_used(ln->u.sym, false, false); 4645 } 4646 } 4647 4648 static void 4649 check_expr_assign(const tnode_t *ln, bool szof) 4650 { 4651 /* XXX: Taking warn_about_unreachable into account here feels wrong. */ 4652 if (ln->tn_op == NAME && !szof && (reached || !warn_about_unreachable)) { 4653 mark_as_set(ln->u.sym); 4654 if (ln->u.sym->s_scl == EXTERN) 4655 outusg(ln->u.sym); 4656 } 4657 check_array_index(ln, false); 4658 } 4659 4660 static void 4661 check_expr_call(const tnode_t *tn, const tnode_t *ln, 4662 bool szof, bool vctx, bool cond, bool retval_discarded) 4663 { 4664 lint_assert(ln->tn_op == ADDR); 4665 lint_assert(ln->u.ops.left->tn_op == NAME); 4666 if (!szof && !is_compiler_builtin(ln->u.ops.left->u.sym->s_name)) 4667 outcall(tn, vctx || cond, retval_discarded); 4668 4669 const function_call *call = tn->u.call; 4670 if (call->args_len == 4 || call->args_len == 5) 4671 check_snprintb(call); 4672 } 4673 4674 static void 4675 check_expr_op(op_t op, const tnode_t *ln, bool szof, bool fcall, bool eqwarn) 4676 { 4677 switch (op) { 4678 case ADDR: 4679 check_expr_addr(ln, szof, fcall); 4680 break; 4681 case LOAD: 4682 check_array_index(ln, false); 4683 /* FALLTHROUGH */ 4684 case INCBEF: 4685 case DECBEF: 4686 case INCAFT: 4687 case DECAFT: 4688 case ADDASS: 4689 case SUBASS: 4690 case MULASS: 4691 case DIVASS: 4692 case MODASS: 4693 case ANDASS: 4694 case ORASS: 4695 case XORASS: 4696 case SHLASS: 4697 case SHRASS: 4698 case REAL: 4699 case IMAG: 4700 check_expr_side_effect(ln, szof); 4701 break; 4702 case ASSIGN: 4703 check_expr_assign(ln, szof); 4704 break; 4705 case EQ: 4706 if (hflag && eqwarn) 4707 /* operator '==' found where '=' was expected */ 4708 warning(160); 4709 break; 4710 default: 4711 break; 4712 } 4713 } 4714 4715 /* 4716 * vctx ??? 4717 * cond whether the expression is a condition that 4718 * will be compared with 0 4719 * eqwarn whether the operator '==' might be a 4720 * misspelled '=' 4721 * fcall whether the expression is a function call 4722 * retval_discarded whether the return value of a function call 4723 * is discarded; such calls will be analyzed by 4724 * lint2 in messages 4, 8 and 9 4725 * szof whether the expression is part of a sizeof 4726 * expression, which means that its value is 4727 * discarded since only the type is relevant 4728 */ 4729 void 4730 check_expr_misc(const tnode_t *tn, bool vctx, bool cond, 4731 bool eqwarn, bool fcall, bool retval_discarded, bool szof) 4732 { 4733 4734 if (tn == NULL) 4735 return; 4736 op_t op = tn->tn_op; 4737 if (op == NAME || op == CON || op == STRING) 4738 return; 4739 bool is_direct = op == CALL 4740 && tn->u.call->func->tn_op == ADDR 4741 && tn->u.call->func->u.ops.left->tn_op == NAME; 4742 if (op == CALL) { 4743 const function_call *call = tn->u.call; 4744 if (is_direct) 4745 check_expr_call(tn, call->func, 4746 szof, vctx, cond, retval_discarded); 4747 bool discard = op == CVT && tn->tn_type->t_tspec == VOID; 4748 check_expr_misc(call->func, false, false, false, is_direct, 4749 discard, szof); 4750 for (size_t i = 0, n = call->args_len; i < n; i++) 4751 check_expr_misc(call->args[i], 4752 true, false, false, false, false, szof); 4753 return; 4754 } 4755 4756 lint_assert(has_operands(tn)); 4757 tnode_t *ln = tn->u.ops.left; 4758 tnode_t *rn = tn->u.ops.right; 4759 check_expr_op(op, ln, szof, fcall, eqwarn); 4760 4761 const mod_t *mp = &modtab[op]; 4762 bool cvctx = mp->m_value_context; 4763 bool ccond = mp->m_compares_with_zero; 4764 bool eq = mp->m_warn_if_operand_eq && 4765 !ln->tn_parenthesized && 4766 rn != NULL && !rn->tn_parenthesized; 4767 4768 /* 4769 * Values of operands of ':' are not used if the type of at least 4770 * one of the operands (for GCC compatibility) is 'void'. 4771 * 4772 * XXX test/value context of QUEST should probably be used as 4773 * context for both operands of COLON. 4774 */ 4775 if (op == COLON && tn->tn_type->t_tspec == VOID) 4776 cvctx = ccond = false; 4777 bool discard = op == CVT && tn->tn_type->t_tspec == VOID; 4778 check_expr_misc(ln, cvctx, ccond, eq, is_direct, discard, szof); 4779 4780 switch (op) { 4781 case LOGAND: 4782 case LOGOR: 4783 check_expr_misc(rn, false, true, eq, false, false, szof); 4784 break; 4785 case COLON: 4786 check_expr_misc(rn, cvctx, ccond, eq, false, false, szof); 4787 break; 4788 case COMMA: 4789 check_expr_misc(rn, vctx, cond, false, false, false, szof); 4790 break; 4791 default: 4792 if (mp->m_binary) 4793 check_expr_misc(rn, true, false, eq, false, false, 4794 szof); 4795 break; 4796 } 4797 } 4798 4799 /* 4800 * Return whether the expression can be used for static initialization. 4801 * 4802 * Constant initialization expressions must be constant or an address 4803 * of a static object with an optional offset. In the first case, 4804 * the result is returned in *offsp. In the second case, the static 4805 * object is returned in *symp and the offset in *offsp. 4806 * 4807 * The expression can consist of PLUS, MINUS, ADDR, NAME, STRING and 4808 * CON. Type conversions are allowed if they do not change binary 4809 * representation (including width). 4810 * 4811 * C99 6.6 "Constant expressions" 4812 * C99 6.7.8p4 restricts initializers for static storage duration 4813 */ 4814 bool 4815 constant_addr(const tnode_t *tn, const sym_t **symp, ptrdiff_t *offsp) 4816 { 4817 const sym_t *sym; 4818 ptrdiff_t offs1, offs2; 4819 tspec_t t, ot; 4820 4821 switch (tn->tn_op) { 4822 case MINUS: 4823 if (tn->u.ops.right->tn_op == CVT) 4824 return constant_addr(tn->u.ops.right, symp, offsp); 4825 else if (tn->u.ops.right->tn_op != CON) 4826 return false; 4827 /* FALLTHROUGH */ 4828 case PLUS: 4829 offs1 = offs2 = 0; 4830 if (tn->u.ops.left->tn_op == CON) { 4831 offs1 = (ptrdiff_t)tn->u.ops.left->u.value.u.integer; 4832 if (!constant_addr(tn->u.ops.right, &sym, &offs2)) 4833 return false; 4834 } else if (tn->u.ops.right->tn_op == CON) { 4835 offs2 = (ptrdiff_t)tn->u.ops.right->u.value.u.integer; 4836 if (tn->tn_op == MINUS) 4837 offs2 = -offs2; 4838 if (!constant_addr(tn->u.ops.left, &sym, &offs1)) 4839 return false; 4840 } else { 4841 return false; 4842 } 4843 *symp = sym; 4844 *offsp = offs1 + offs2; 4845 return true; 4846 case ADDR: 4847 if (tn->u.ops.left->tn_op == NAME) { 4848 *symp = tn->u.ops.left->u.sym; 4849 *offsp = 0; 4850 return true; 4851 } else { 4852 /* 4853 * If this were the front end of a compiler, we would 4854 * return a label instead of 0, at least if 4855 * 'tn->u.ops.left->tn_op == STRING'. 4856 */ 4857 *symp = NULL; 4858 *offsp = 0; 4859 return true; 4860 } 4861 case CVT: 4862 t = tn->tn_type->t_tspec; 4863 ot = tn->u.ops.left->tn_type->t_tspec; 4864 if ((!is_integer(t) && t != PTR) || 4865 (!is_integer(ot) && ot != PTR)) { 4866 return false; 4867 } 4868 #if 0 4869 /*- 4870 * consider: 4871 * struct foo { 4872 * unsigned char a; 4873 * } f = { 4874 * (unsigned char)(unsigned long) 4875 * (&(((struct foo *)0)->a)) 4876 * }; 4877 * since psize(unsigned long) != psize(unsigned char), 4878 * this fails. 4879 */ 4880 else if (psize(t) != psize(ot)) 4881 return -1; 4882 #endif 4883 return constant_addr(tn->u.ops.left, symp, offsp); 4884 default: 4885 return false; 4886 } 4887 } 4888 4889 /* Append s2 to s1, then free s2. */ 4890 buffer * 4891 cat_strings(buffer *s1, buffer *s2) 4892 { 4893 4894 if ((s1->data != NULL) != (s2->data != NULL)) { 4895 /* cannot concatenate wide and regular string literals */ 4896 error(292); 4897 return s1; 4898 } 4899 4900 if (s1->data != NULL) { 4901 while (s1->len + s2->len + 1 > s1->cap) 4902 s1->cap *= 2; 4903 s1->data = xrealloc(s1->data, s1->cap); 4904 memcpy(s1->data + s1->len, s2->data, s2->len + 1); 4905 free(s2->data); 4906 } 4907 s1->len += s2->len; 4908 free(s2); 4909 4910 return s1; 4911 } 4912 4913 4914 typedef struct stmt_expr { 4915 memory_pool se_mem; 4916 sym_t *se_sym; 4917 struct stmt_expr *se_enclosing; 4918 } stmt_expr; 4919 4920 static stmt_expr *stmt_exprs; 4921 4922 void 4923 begin_statement_expr(void) 4924 { 4925 debug_enter(); 4926 4927 stmt_expr *se = xmalloc(sizeof(*se)); 4928 se->se_mem = expr_save_memory(); 4929 se->se_sym = NULL; 4930 se->se_enclosing = stmt_exprs; 4931 stmt_exprs = se; 4932 } 4933 4934 void 4935 do_statement_expr(tnode_t *tn) 4936 { 4937 block_level--; 4938 mem_block_level--; 4939 stmt_exprs->se_sym = tn != NULL 4940 ? mktempsym(block_dup_type(tn->tn_type)) 4941 : NULL; /* after a syntax error */ 4942 mem_block_level++; 4943 block_level++; 4944 /* '({ ... })' is a GCC extension */ 4945 gnuism(320); 4946 } 4947 4948 tnode_t * 4949 end_statement_expr(void) 4950 { 4951 tnode_t *tn; 4952 4953 stmt_expr *se = stmt_exprs; 4954 if (se->se_sym == NULL) { 4955 tn = NULL; /* after a syntax error */ 4956 goto end; 4957 } 4958 4959 tn = build_name(se->se_sym, false); 4960 (void)expr_save_memory(); /* leak */ 4961 expr_restore_memory(se->se_mem); 4962 stmt_exprs = se->se_enclosing; 4963 free(se); 4964 4965 end: 4966 debug_leave(); 4967 return tn; 4968 } 4969 4970 bool 4971 in_statement_expr(void) 4972 { 4973 return stmt_exprs != NULL; 4974 } 4975
Indexes created Mon Sep 22 13:09:51 GMT 2025