tree.c revision 1.661
1 /* $NetBSD: tree.c,v 1.661 2024/11/29 06:57:43 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 1.661 2024/11/29 06:57:43 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 (!in_system_header) { 712 if (lt == CHAR && rn->tn_op == CON && 713 !rn->u.value.v_char_constant) { 714 /* comparison '%s' of 'char' with plain integer %d */ 715 query_message(14, 716 op_name(op), (int)rn->u.value.u.integer); 717 } 718 if (rt == CHAR && ln->tn_op == CON && 719 !ln->u.value.v_char_constant) { 720 /* comparison '%s' of 'char' with plain integer %d */ 721 query_message(14, 722 op_name(op), (int)ln->u.value.u.integer); 723 } 724 } 725 726 if (!check_nonportable_char_comparison(op, ln, lt, rn, rt)) 727 return; 728 729 if (is_uinteger(lt) && !is_uinteger(rt) && 730 rn->tn_op == CON && rn->u.value.u.integer <= 0) { 731 if (rn->u.value.u.integer < 0) { 732 /* operator '%s' compares '%s' with '%s' */ 733 warning(162, op_name(op), 734 type_name(ln->tn_type), "negative constant"); 735 } else if (op == LT || op == GE) 736 /* operator '%s' compares '%s' with '%s' */ 737 warning(162, op_name(op), type_name(ln->tn_type), "0"); 738 return; 739 } 740 if (is_uinteger(rt) && !is_uinteger(lt) && 741 ln->tn_op == CON && ln->u.value.u.integer <= 0) { 742 if (ln->u.value.u.integer < 0) { 743 /* operator '%s' compares '%s' with '%s' */ 744 warning(162, op_name(op), 745 "negative constant", type_name(rn->tn_type)); 746 } else if (op == GT || op == LE) 747 /* operator '%s' compares '%s' with '%s' */ 748 warning(162, op_name(op), "0", type_name(rn->tn_type)); 749 return; 750 } 751 } 752 753 static const tspec_t arith_rank[] = { 754 LDOUBLE, DOUBLE, FLOAT, 755 #ifdef INT128_SIZE 756 UINT128, INT128, 757 #endif 758 ULLONG, LLONG, 759 ULONG, LONG, 760 UINT, INT, 761 }; 762 763 /* Keep unsigned in traditional C */ 764 static tspec_t 765 usual_arithmetic_conversion_trad(tspec_t lt, tspec_t rt) 766 { 767 768 size_t i; 769 for (i = 0; arith_rank[i] != INT; i++) 770 if (lt == arith_rank[i] || rt == arith_rank[i]) 771 break; 772 773 tspec_t t = arith_rank[i]; 774 if (is_uinteger(lt) || is_uinteger(rt)) 775 if (is_integer(t) && !is_uinteger(t)) 776 return unsigned_type(t); 777 return t; 778 } 779 780 static tspec_t 781 usual_arithmetic_conversion_c90(tspec_t lt, tspec_t rt) 782 { 783 784 if (lt == rt) 785 return lt; 786 787 if (lt == LCOMPLEX || rt == LCOMPLEX) 788 return LCOMPLEX; 789 if (lt == DCOMPLEX || rt == DCOMPLEX) 790 return DCOMPLEX; 791 if (lt == FCOMPLEX || rt == FCOMPLEX) 792 return FCOMPLEX; 793 if (lt == LDOUBLE || rt == LDOUBLE) 794 return LDOUBLE; 795 if (lt == DOUBLE || rt == DOUBLE) 796 return DOUBLE; 797 if (lt == FLOAT || rt == FLOAT) 798 return FLOAT; 799 800 if (size_in_bits(lt) > size_in_bits(rt)) 801 return lt; 802 if (size_in_bits(lt) < size_in_bits(rt)) 803 return rt; 804 805 size_t i; 806 for (i = 3; arith_rank[i] != INT; i++) 807 if (arith_rank[i] == lt || arith_rank[i] == rt) 808 break; 809 if ((is_uinteger(lt) || is_uinteger(rt)) && 810 !is_uinteger(arith_rank[i])) 811 i--; 812 return arith_rank[i]; 813 } 814 815 static tnode_t * 816 apply_usual_arithmetic_conversions(op_t op, tnode_t *tn, tspec_t t) 817 { 818 type_t *ntp = expr_dup_type(tn->tn_type); 819 ntp->t_tspec = t; 820 if (tn->tn_op != CON) { 821 /* usual arithmetic conversion for '%s' from '%s' to '%s' */ 822 query_message(4, op_name(op), 823 type_name(tn->tn_type), type_name(ntp)); 824 } 825 return convert(op, 0, ntp, tn); 826 } 827 828 /* 829 * Apply the "usual arithmetic conversions" (C99 6.3.1.8), which gives both 830 * operands the same type. 831 */ 832 static void 833 balance(op_t op, tnode_t **lnp, tnode_t **rnp) 834 { 835 836 tspec_t lt = (*lnp)->tn_type->t_tspec; 837 tspec_t rt = (*rnp)->tn_type->t_tspec; 838 if (!is_arithmetic(lt) || !is_arithmetic(rt)) 839 return; 840 841 tspec_t t = allow_c90 842 ? usual_arithmetic_conversion_c90(lt, rt) 843 : usual_arithmetic_conversion_trad(lt, rt); 844 845 if (modtab[op].m_comparison 846 && is_integer(lt) && (*lnp)->tn_op != CON 847 && is_floating(t) && (*rnp)->tn_op == CON) 848 /* comparing integer '%s' to floating point constant %Lg */ 849 warning(379, type_name((*lnp)->tn_type), 850 (*rnp)->u.value.u.floating); 851 852 if (t != lt) 853 *lnp = apply_usual_arithmetic_conversions(op, *lnp, t); 854 if (t != rt) 855 *rnp = apply_usual_arithmetic_conversions(op, *rnp, t); 856 857 if (is_integer(t)) { 858 unsigned lw = width_in_bits((*lnp)->tn_type); 859 unsigned rw = width_in_bits((*rnp)->tn_type); 860 if (lw < rw) 861 *lnp = convert(NOOP, 0, (*rnp)->tn_type, *lnp); 862 if (rw < lw) 863 *rnp = convert(NOOP, 0, (*lnp)->tn_type, *rnp); 864 } 865 } 866 867 static tnode_t * 868 build_address(bool sys, tnode_t *tn, bool force) 869 { 870 tspec_t t; 871 872 if (!force && ((t = tn->tn_type->t_tspec) == ARRAY || t == FUNC)) { 873 if (!allow_c90) 874 /* '&' before array or function: ignored */ 875 warning(127); 876 return tn; 877 } 878 879 /* eliminate '&*' */ 880 if (tn->tn_op == INDIR && 881 tn->u.ops.left->tn_type->t_tspec == PTR && 882 tn->u.ops.left->tn_type->t_subt == tn->tn_type) { 883 return tn->u.ops.left; 884 } 885 886 return build_op(ADDR, sys, expr_derive_type(tn->tn_type, PTR), 887 tn, NULL); 888 } 889 890 static uint64_t 891 fold_unsigned_integer(op_t op, uint64_t l, uint64_t r, 892 uint64_t max_value, bool *overflow) 893 { 894 switch (op) { 895 case COMPL: 896 return ~l & max_value; 897 case UPLUS: 898 return +l; 899 case UMINUS: 900 return -l & max_value; 901 case MULT: 902 *overflow = r > 0 && l > max_value / r; 903 return l * r; 904 case DIV: 905 if (r == 0) { 906 /* division by 0 */ 907 error(139); 908 return max_value; 909 } 910 return l / r; 911 case MOD: 912 if (r == 0) { 913 /* modulus by 0 */ 914 error(140); 915 return 0; 916 } 917 return l % r; 918 case PLUS: 919 *overflow = l > max_value - r; 920 return l + r; 921 case MINUS: 922 *overflow = l < r; 923 return l - r; 924 case SHL: 925 /* TODO: warn about out-of-bounds 'r'. */ 926 /* TODO: warn about overflow. */ 927 return l << (r & 63); 928 case SHR: 929 /* TODO: warn about out-of-bounds 'r'. */ 930 return l >> (r & 63); 931 case LT: 932 return l < r ? 1 : 0; 933 case LE: 934 return l <= r ? 1 : 0; 935 case GT: 936 return l > r ? 1 : 0; 937 case GE: 938 return l >= r ? 1 : 0; 939 case EQ: 940 return l == r ? 1 : 0; 941 case NE: 942 return l != r ? 1 : 0; 943 case BITAND: 944 return l & r; 945 case BITXOR: 946 return l ^ r; 947 case BITOR: 948 return l | r; 949 default: 950 lint_assert(/*CONSTCOND*/false); 951 /* NOTREACHED */ 952 } 953 } 954 955 static int64_t 956 fold_signed_integer(op_t op, int64_t l, int64_t r, 957 int64_t min_value, int64_t max_value, bool *overflow) 958 { 959 switch (op) { 960 case COMPL: 961 return ~l; 962 case UPLUS: 963 return +l; 964 case UMINUS: 965 *overflow = l == min_value; 966 return *overflow ? l : -l; 967 case MULT:; 968 uint64_t al = l >= 0 ? (uint64_t)l : -(uint64_t)l; 969 uint64_t ar = r >= 0 ? (uint64_t)r : -(uint64_t)r; 970 bool neg = (l >= 0) != (r >= 0); 971 uint64_t max_prod = (uint64_t)max_value + (neg ? 1 : 0); 972 if (al > 0 && ar > max_prod / al) { 973 *overflow = true; 974 return neg ? min_value : max_value; 975 } 976 return l * r; 977 case DIV: 978 if (r == 0) { 979 /* division by 0 */ 980 error(139); 981 return max_value; 982 } 983 if (l == min_value && r == -1) { 984 *overflow = true; 985 return l; 986 } 987 return l / r; 988 case MOD: 989 if (r == 0) { 990 /* modulus by 0 */ 991 error(140); 992 return 0; 993 } 994 if (l == min_value && r == -1) { 995 *overflow = true; 996 return 0; 997 } 998 return l % r; 999 case PLUS: 1000 if (r > 0 && l > max_value - r) { 1001 *overflow = true; 1002 return max_value; 1003 } 1004 if (r < 0 && l < min_value - r) { 1005 *overflow = true; 1006 return min_value; 1007 } 1008 return l + r; 1009 case MINUS: 1010 if (r > 0 && l < min_value + r) { 1011 *overflow = true; 1012 return min_value; 1013 } 1014 if (r < 0 && l > max_value + r) { 1015 *overflow = true; 1016 return max_value; 1017 } 1018 return l - r; 1019 case SHL: 1020 /* TODO: warn about out-of-bounds 'r'. */ 1021 /* TODO: warn about overflow. */ 1022 return l << (r & 63); 1023 case SHR: 1024 /* TODO: warn about out-of-bounds 'r'. */ 1025 if (l < 0) 1026 return (int64_t)~(~(uint64_t)l >> (r & 63)); 1027 return (int64_t)((uint64_t)l >> (r & 63)); 1028 case LT: 1029 return l < r ? 1 : 0; 1030 case LE: 1031 return l <= r ? 1 : 0; 1032 case GT: 1033 return l > r ? 1 : 0; 1034 case GE: 1035 return l >= r ? 1 : 0; 1036 case EQ: 1037 return l == r ? 1 : 0; 1038 case NE: 1039 return l != r ? 1 : 0; 1040 case BITAND: 1041 return l & r; 1042 case BITXOR: 1043 return l ^ r; 1044 case BITOR: 1045 return l | r; 1046 default: 1047 lint_assert(/*CONSTCOND*/false); 1048 /* NOTREACHED */ 1049 } 1050 } 1051 1052 static tnode_t * 1053 fold_constant_integer(tnode_t *tn) 1054 { 1055 1056 lint_assert(has_operands(tn)); 1057 tspec_t t = tn->u.ops.left->tn_type->t_tspec; 1058 int64_t l = tn->u.ops.left->u.value.u.integer; 1059 int64_t r = is_binary(tn) ? tn->u.ops.right->u.value.u.integer : 0; 1060 uint64_t mask = value_bits(size_in_bits(t)); 1061 1062 int64_t res; 1063 bool overflow = false; 1064 if (!is_integer(t) || is_uinteger(t)) { 1065 uint64_t u_res = fold_unsigned_integer(tn->tn_op, 1066 (uint64_t)l, (uint64_t)r, mask, &overflow); 1067 if (u_res > mask) 1068 overflow = true; 1069 res = (int64_t)u_res; 1070 if (overflow && hflag) { 1071 char buf[128]; 1072 if (is_binary(tn)) { 1073 snprintf(buf, sizeof(buf), "%ju %s %ju", 1074 (uintmax_t)l, op_name(tn->tn_op), 1075 (uintmax_t)r); 1076 } else { 1077 snprintf(buf, sizeof(buf), "%s%ju", 1078 op_name(tn->tn_op), (uintmax_t)l); 1079 } 1080 /* '%s' overflows '%s' */ 1081 warning(141, buf, type_name(tn->tn_type)); 1082 } 1083 } else { 1084 int64_t max_value = (int64_t)(mask >> 1); 1085 int64_t min_value = -max_value - 1; 1086 res = fold_signed_integer(tn->tn_op, 1087 l, r, min_value, max_value, &overflow); 1088 if (res < min_value || res > max_value) 1089 overflow = true; 1090 if (overflow && hflag) { 1091 char buf[128]; 1092 if (is_binary(tn)) { 1093 snprintf(buf, sizeof(buf), "%jd %s %jd", 1094 (intmax_t)l, op_name(tn->tn_op), 1095 (intmax_t)r); 1096 } else if (tn->tn_op == UMINUS && l < 0) { 1097 snprintf(buf, sizeof(buf), "-(%jd)", 1098 (intmax_t)l); 1099 } else { 1100 snprintf(buf, sizeof(buf), "%s%jd", 1101 op_name(tn->tn_op), (intmax_t)l); 1102 } 1103 /* '%s' overflows '%s' */ 1104 warning(141, buf, type_name(tn->tn_type)); 1105 } 1106 } 1107 1108 val_t *v = xcalloc(1, sizeof(*v)); 1109 v->v_tspec = tn->tn_type->t_tspec; 1110 v->u.integer = convert_integer(res, t, size_in_bits(t)); 1111 1112 tnode_t *cn = build_constant(tn->tn_type, v); 1113 if (tn->u.ops.left->tn_system_dependent) 1114 cn->tn_system_dependent = true; 1115 if (is_binary(tn) && tn->u.ops.right->tn_system_dependent) 1116 cn->tn_system_dependent = true; 1117 1118 return cn; 1119 } 1120 1121 static tnode_t * 1122 build_struct_access(op_t op, bool sys, tnode_t *ln, tnode_t *rn) 1123 { 1124 1125 lint_assert(rn->tn_op == NAME); 1126 lint_assert(is_member(rn->u.sym)); 1127 1128 bool lvalue = op == ARROW || ln->tn_lvalue; 1129 1130 if (op == POINT) 1131 ln = build_address(sys, ln, true); 1132 else if (ln->tn_type->t_tspec != PTR) { 1133 lint_assert(!allow_c90); 1134 lint_assert(is_integer(ln->tn_type->t_tspec)); 1135 ln = convert(NOOP, 0, expr_derive_type(gettyp(VOID), PTR), ln); 1136 } 1137 1138 tnode_t *ctn = build_integer_constant(PTRDIFF_TSPEC, 1139 rn->u.sym->u.s_member.sm_offset_in_bits / CHAR_SIZE); 1140 1141 type_t *ptr_tp = expr_derive_type(rn->tn_type, PTR); 1142 tnode_t *ntn = build_op(PLUS, sys, ptr_tp, ln, ctn); 1143 if (ln->tn_op == CON) 1144 ntn = fold_constant_integer(ntn); 1145 1146 op_t nop = rn->tn_type->t_bitfield ? FSEL : INDIR; 1147 ntn = build_op(nop, sys, ntn->tn_type->t_subt, ntn, NULL); 1148 if (!lvalue) 1149 ntn->tn_lvalue = false; 1150 1151 return ntn; 1152 } 1153 1154 /* 1155 * Get the size in bytes of type tp->t_subt, as a constant expression of type 1156 * ptrdiff_t as seen from the target platform. 1157 */ 1158 static tnode_t * 1159 subt_size_in_bytes(type_t *tp) 1160 { 1161 1162 lint_assert(tp->t_tspec == PTR); 1163 tp = tp->t_subt; 1164 1165 int elem = 1; 1166 while (tp->t_tspec == ARRAY) { 1167 elem *= tp->u.dimension; 1168 tp = tp->t_subt; 1169 } 1170 1171 int elsz_in_bits = 0; 1172 switch (tp->t_tspec) { 1173 case FUNC: 1174 /* pointer to function is not allowed here */ 1175 error(110); 1176 break; 1177 case VOID: 1178 /* cannot do pointer arithmetic on operand of unknown size */ 1179 gnuism(136); 1180 break; 1181 case STRUCT: 1182 case UNION: 1183 if ((elsz_in_bits = (int)tp->u.sou->sou_size_in_bits) == 0) 1184 /* cannot do pointer arithmetic on operand of ... */ 1185 error(136); 1186 break; 1187 case ENUM: 1188 if (is_incomplete(tp)) 1189 /* cannot do pointer arithmetic on operand of ... */ 1190 warning(136); 1191 /* FALLTHROUGH */ 1192 default: 1193 if ((elsz_in_bits = size_in_bits(tp->t_tspec)) == 0) 1194 /* cannot do pointer arithmetic on operand of ... */ 1195 error(136); 1196 else 1197 lint_assert(elsz_in_bits != -1); 1198 break; 1199 } 1200 1201 if (elem == 0 && elsz_in_bits != 0) 1202 /* cannot do pointer arithmetic on operand of unknown size */ 1203 error(136); 1204 1205 if (elsz_in_bits == 0) 1206 elsz_in_bits = CHAR_SIZE; 1207 1208 return build_integer_constant(PTRDIFF_TSPEC, 1209 (int64_t)(elem * elsz_in_bits / CHAR_SIZE)); 1210 } 1211 1212 static tnode_t * 1213 build_prepost_incdec(op_t op, bool sys, tnode_t *ln) 1214 { 1215 1216 lint_assert(ln != NULL); 1217 tnode_t *cn = ln->tn_type->t_tspec == PTR 1218 ? subt_size_in_bytes(ln->tn_type) 1219 : build_integer_constant(INT, 1); 1220 return build_op(op, sys, ln->tn_type, ln, cn); 1221 } 1222 1223 static void 1224 check_enum_array_index(const tnode_t *ln, const tnode_t *rn) 1225 { 1226 1227 if (ln->tn_op != ADDR || ln->u.ops.left->tn_op != NAME) 1228 return; 1229 1230 const type_t *ltp = ln->u.ops.left->tn_type; 1231 if (ltp->t_tspec != ARRAY || ltp->t_incomplete_array) 1232 return; 1233 1234 if (rn->tn_op != CVT || !rn->tn_type->t_is_enum) 1235 return; 1236 if (rn->u.ops.left->tn_op != LOAD) 1237 return; 1238 1239 const type_t *rtp = rn->u.ops.left->tn_type; 1240 const sym_t *ec = rtp->u.enumer->en_first_enumerator; 1241 const sym_t *max_ec = ec; 1242 lint_assert(ec != NULL); 1243 for (ec = ec->s_next; ec != NULL; ec = ec->s_next) 1244 if (ec->u.s_enum_constant > max_ec->u.s_enum_constant) 1245 max_ec = ec; 1246 1247 int64_t max_enum_value = max_ec->u.s_enum_constant; 1248 lint_assert(INT_MIN <= max_enum_value && max_enum_value <= INT_MAX); 1249 1250 int max_array_index = ltp->u.dimension - 1; 1251 if (max_enum_value == max_array_index) 1252 return; 1253 1254 if (max_enum_value == max_array_index + 1 && 1255 (strstr(max_ec->s_name, "MAX") != NULL || 1256 strstr(max_ec->s_name, "max") != NULL || 1257 strstr(max_ec->s_name, "NUM") != NULL || 1258 strstr(max_ec->s_name, "num") != NULL || 1259 strncmp(max_ec->s_name, "N_", 2) == 0)) 1260 return; 1261 1262 /* maximum value %d for '%s' of type '%s' does not match maximum array index %d */ 1263 warning(348, (int)max_enum_value, max_ec->s_name, type_name(rtp), 1264 max_array_index); 1265 print_previous_declaration(max_ec); 1266 } 1267 1268 static tnode_t * 1269 build_plus_minus(op_t op, bool sys, tnode_t *ln, tnode_t *rn) 1270 { 1271 1272 if (rn->tn_type->t_tspec == PTR && is_integer(ln->tn_type->t_tspec)) { 1273 tnode_t *tmp = ln; 1274 ln = rn; 1275 rn = tmp; 1276 /* pointer addition has integer on the left-hand side */ 1277 query_message(5); 1278 } 1279 1280 /* pointer +- integer */ 1281 tspec_t lt = ln->tn_type->t_tspec; 1282 tspec_t rt = rn->tn_type->t_tspec; 1283 if (lt == PTR && rt != PTR) { 1284 lint_assert(is_integer(rt)); 1285 1286 check_ctype_macro_invocation(ln, rn); 1287 check_enum_array_index(ln, rn); 1288 1289 tnode_t *elsz = subt_size_in_bytes(ln->tn_type); 1290 tspec_t szt = elsz->tn_type->t_tspec; 1291 if (rt != szt && rt != unsigned_type(szt)) 1292 rn = convert(NOOP, 0, elsz->tn_type, rn); 1293 1294 tnode_t *prod = build_op(MULT, sys, rn->tn_type, rn, elsz); 1295 if (rn->tn_op == CON) 1296 prod = fold_constant_integer(prod); 1297 1298 return build_op(op, sys, ln->tn_type, ln, prod); 1299 } 1300 1301 /* pointer - pointer */ 1302 if (rt == PTR) { 1303 lint_assert(lt == PTR); 1304 lint_assert(op == MINUS); 1305 1306 type_t *ptrdiff = gettyp(PTRDIFF_TSPEC); 1307 tnode_t *raw_diff = build_op(op, sys, ptrdiff, ln, rn); 1308 if (ln->tn_op == CON && rn->tn_op == CON) 1309 raw_diff = fold_constant_integer(raw_diff); 1310 1311 tnode_t *elsz = subt_size_in_bytes(ln->tn_type); 1312 balance(NOOP, &raw_diff, &elsz); 1313 1314 return build_op(DIV, sys, ptrdiff, raw_diff, elsz); 1315 } 1316 1317 return build_op(op, sys, ln->tn_type, ln, rn); 1318 } 1319 1320 static tnode_t * 1321 build_bit_shift(op_t op, bool sys, tnode_t *ln, tnode_t *rn) 1322 { 1323 1324 if (!allow_c90 && rn->tn_type->t_tspec != INT) 1325 // XXX: C1978 7.5 says: "Both [operators] perform the usual 1326 // arithmetic conversions on their operands." 1327 // TODO: Add a test to exercise this part of the code. 1328 rn = convert(NOOP, 0, gettyp(INT), rn); 1329 return build_op(op, sys, ln->tn_type, ln, rn); 1330 } 1331 1332 static bool 1333 is_null_pointer(const tnode_t *tn) 1334 { 1335 tspec_t t = tn->tn_type->t_tspec; 1336 1337 // TODO: Investigate how other pointers are stored, in particular, 1338 // whether a pointer constant can have a non-zero value. 1339 // If not, simplify the code below. 1340 return ((t == PTR && tn->tn_type->t_subt->t_tspec == VOID) 1341 || is_integer(t)) 1342 && (tn->tn_op == CON && tn->u.value.u.integer == 0); 1343 } 1344 1345 /* Return a type based on tp1, with added qualifiers from tp2. */ 1346 static type_t * 1347 merge_qualifiers(type_t *tp1, const type_t *tp2) 1348 { 1349 1350 lint_assert(tp1->t_tspec == PTR); 1351 lint_assert(tp2->t_tspec == PTR); 1352 1353 bool c1 = tp1->t_subt->t_const; 1354 bool c2 = tp2->t_subt->t_const; 1355 bool v1 = tp1->t_subt->t_volatile; 1356 bool v2 = tp2->t_subt->t_volatile; 1357 1358 if (c1 == (c1 | c2) && v1 == (v1 | v2)) 1359 return tp1; 1360 1361 type_t *nstp = expr_dup_type(tp1->t_subt); 1362 nstp->t_const |= c2; 1363 nstp->t_volatile |= v2; 1364 1365 type_t *ntp = expr_dup_type(tp1); 1366 ntp->t_subt = nstp; 1367 return ntp; 1368 } 1369 1370 /* See C99 6.5.15 "Conditional operator". */ 1371 static tnode_t * 1372 build_colon(bool sys, tnode_t *ln, tnode_t *rn) 1373 { 1374 tspec_t lt = ln->tn_type->t_tspec; 1375 tspec_t rt = rn->tn_type->t_tspec; 1376 1377 type_t *tp; 1378 if (is_arithmetic(lt) && is_arithmetic(rt)) 1379 /* The operands were already balanced in build_binary. */ 1380 tp = ln->tn_type; 1381 else if (lt == BOOL && rt == BOOL) 1382 tp = ln->tn_type; 1383 else if (lt == VOID || rt == VOID) 1384 tp = gettyp(VOID); 1385 else if (is_struct_or_union(lt)) { 1386 lint_assert(is_struct_or_union(rt)); 1387 lint_assert(ln->tn_type->u.sou == rn->tn_type->u.sou); 1388 if (is_incomplete(ln->tn_type)) { 1389 /* unknown operand size, op '%s' */ 1390 error(138, op_name(COLON)); 1391 return NULL; 1392 } 1393 tp = ln->tn_type; 1394 } else if (lt == PTR && is_integer(rt)) { 1395 if (rt != PTRDIFF_TSPEC) 1396 rn = convert(NOOP, 0, gettyp(PTRDIFF_TSPEC), rn); 1397 tp = ln->tn_type; 1398 } else if (rt == PTR && is_integer(lt)) { 1399 if (lt != PTRDIFF_TSPEC) 1400 ln = convert(NOOP, 0, gettyp(PTRDIFF_TSPEC), ln); 1401 tp = rn->tn_type; 1402 } else if (lt == PTR && is_null_pointer(rn)) 1403 tp = merge_qualifiers(ln->tn_type, rn->tn_type); 1404 else if (rt == PTR && is_null_pointer(ln)) 1405 tp = merge_qualifiers(rn->tn_type, ln->tn_type); 1406 else if (lt == PTR && ln->tn_type->t_subt->t_tspec == VOID) 1407 tp = merge_qualifiers(ln->tn_type, rn->tn_type); 1408 else if (rt == PTR && rn->tn_type->t_subt->t_tspec == VOID) 1409 tp = merge_qualifiers(rn->tn_type, ln->tn_type); 1410 else { 1411 /* 1412 * XXX For now we simply take the left type. This is probably 1413 * wrong, if one type contains a function prototype and the 1414 * other one, at the same place, only an old-style declaration. 1415 */ 1416 tp = merge_qualifiers(ln->tn_type, rn->tn_type); 1417 } 1418 1419 return build_op(COLON, sys, tp, ln, rn); 1420 } 1421 1422 /* TODO: check for varargs */ 1423 static bool 1424 is_cast_redundant(const tnode_t *tn) 1425 { 1426 const type_t *ntp = tn->tn_type, *otp = tn->u.ops.left->tn_type; 1427 tspec_t nt = ntp->t_tspec, ot = otp->t_tspec; 1428 1429 if (nt == BOOL || ot == BOOL) 1430 return nt == BOOL && ot == BOOL; 1431 1432 if (is_integer(nt) && is_integer(ot)) { 1433 unsigned int nw = width_in_bits(ntp), ow = width_in_bits(otp); 1434 if (is_uinteger(nt) == is_uinteger(ot)) 1435 return nw >= ow; 1436 return is_uinteger(ot) && nw > ow; 1437 } 1438 1439 if (is_complex(nt) || is_complex(ot)) 1440 return is_complex(nt) && is_complex(ot) && 1441 size_in_bits(nt) >= size_in_bits(ot); 1442 1443 if (is_floating(nt) && is_floating(ot)) 1444 return size_in_bits(nt) >= size_in_bits(ot); 1445 1446 if (nt == PTR && ot == PTR) { 1447 if (!ntp->t_subt->t_const && otp->t_subt->t_const) 1448 return false; 1449 if (!ntp->t_subt->t_volatile && otp->t_subt->t_volatile) 1450 return false; 1451 1452 if (ntp->t_subt->t_tspec == VOID || 1453 otp->t_subt->t_tspec == VOID || 1454 types_compatible(ntp->t_subt, otp->t_subt, 1455 false, false, NULL)) 1456 return true; 1457 } 1458 1459 return false; 1460 } 1461 1462 static bool 1463 is_assignment(op_t op) 1464 { 1465 1466 return op == ASSIGN || 1467 op == MULASS || 1468 op == DIVASS || 1469 op == MODASS || 1470 op == ADDASS || 1471 op == SUBASS || 1472 op == SHLASS || 1473 op == SHRASS || 1474 op == ANDASS || 1475 op == XORASS || 1476 op == ORASS || 1477 op == RETURN || 1478 op == INIT; 1479 } 1480 1481 static tnode_t * 1482 build_assignment(op_t op, bool sys, tnode_t *ln, tnode_t *rn) 1483 { 1484 1485 tspec_t lt = ln->tn_type->t_tspec; 1486 tspec_t rt = rn->tn_type->t_tspec; 1487 1488 if (is_assignment(rn->tn_op)) 1489 /* chained assignment with '%s' and '%s' */ 1490 query_message(10, op_name(op), op_name(rn->tn_op)); 1491 1492 if ((op == ADDASS || op == SUBASS) && lt == PTR) { 1493 lint_assert(is_integer(rt)); 1494 tnode_t *ctn = subt_size_in_bytes(ln->tn_type); 1495 if (rn->tn_type->t_tspec != ctn->tn_type->t_tspec) 1496 rn = convert(NOOP, 0, ctn->tn_type, rn); 1497 rn = build_op(MULT, sys, rn->tn_type, rn, ctn); 1498 if (rn->u.ops.left->tn_op == CON) 1499 rn = fold_constant_integer(rn); 1500 } 1501 1502 if ((op == ASSIGN || op == RETURN || op == INIT) && 1503 (lt == STRUCT || rt == STRUCT)) { 1504 lint_assert(lt == rt); 1505 lint_assert(ln->tn_type->u.sou == rn->tn_type->u.sou); 1506 if (is_incomplete(ln->tn_type)) { 1507 if (op == RETURN) 1508 /* cannot return incomplete type */ 1509 error(212); 1510 else 1511 /* unknown operand size, op '%s' */ 1512 error(138, op_name(op)); 1513 return NULL; 1514 } 1515 } 1516 1517 if (op == SHLASS && hflag && allow_trad && allow_c90 1518 && portable_rank_cmp(lt, rt) < 0) 1519 /* semantics of '%s' change in C90; ... */ 1520 warning(118, "<<="); 1521 1522 if (op != SHLASS && op != SHRASS 1523 && (op == ASSIGN || lt != PTR) 1524 && (lt != rt || (ln->tn_type->t_bitfield && rn->tn_op == CON))) { 1525 rn = convert(op, 0, ln->tn_type, rn); 1526 rt = lt; 1527 } 1528 1529 if (lt == PTR && ln->tn_type->t_subt->t_tspec != VOID 1530 && rt == PTR && rn->tn_type->t_subt->t_tspec == VOID 1531 && !is_null_pointer(rn)) 1532 /* implicit narrowing conversion from void ... */ 1533 query_message(20, type_name(ln->tn_type)); 1534 1535 if (rn->tn_op == CVT && rn->tn_cast && 1536 types_compatible(ln->tn_type, rn->tn_type, false, false, NULL) && 1537 is_cast_redundant(rn)) { 1538 /* redundant cast from '%s' to '%s' before assignment */ 1539 query_message(7, type_name(rn->u.ops.left->tn_type), 1540 type_name(rn->tn_type)); 1541 } 1542 1543 return build_op(op, sys, ln->tn_type, ln, rn); 1544 } 1545 1546 static tnode_t * 1547 build_real_imag(op_t op, bool sys, tnode_t *ln) 1548 { 1549 1550 lint_assert(ln != NULL); 1551 if (ln->tn_op == NAME) { 1552 /* 1553 * This may be too much, but it avoids wrong warnings. See 1554 * d_c99_complex_split.c. 1555 */ 1556 mark_as_used(ln->u.sym, false, false); 1557 mark_as_set(ln->u.sym); 1558 } 1559 1560 tspec_t t; 1561 switch (ln->tn_type->t_tspec) { 1562 case LCOMPLEX: 1563 t = LDOUBLE; 1564 break; 1565 case DCOMPLEX: 1566 t = DOUBLE; 1567 break; 1568 case FCOMPLEX: 1569 t = FLOAT; 1570 break; 1571 default: 1572 /* '__%s__' is illegal for type '%s' */ 1573 error(276, op == REAL ? "real" : "imag", 1574 type_name(ln->tn_type)); 1575 return NULL; 1576 } 1577 1578 tnode_t *ntn = build_op(op, sys, gettyp(t), ln, NULL); 1579 ntn->tn_lvalue = true; 1580 return ntn; 1581 } 1582 1583 static bool 1584 is_confusing_precedence(op_t op, op_t lop, bool lparen, op_t rop, bool rparen) 1585 { 1586 1587 if (op == SHL || op == SHR) { 1588 if (!lparen && (lop == PLUS || lop == MINUS)) 1589 return true; 1590 if (!rparen && (rop == PLUS || rop == MINUS)) 1591 return true; 1592 return false; 1593 } 1594 1595 if (op == LOGOR) { 1596 if (!lparen && lop == LOGAND) 1597 return true; 1598 if (!rparen && rop == LOGAND) 1599 return true; 1600 return false; 1601 } 1602 1603 lint_assert(op == BITAND || op == BITXOR || op == BITOR); 1604 if (!lparen && lop != op) { 1605 if (lop == PLUS || lop == MINUS) 1606 return true; 1607 if (lop == BITAND || lop == BITXOR) 1608 return true; 1609 } 1610 if (!rparen && rop != op) { 1611 if (rop == PLUS || rop == MINUS) 1612 return true; 1613 if (rop == BITAND || rop == BITXOR) 1614 return true; 1615 } 1616 return false; 1617 } 1618 1619 /* 1620 * Print a warning if the given node has operands which should be 1621 * parenthesized. 1622 * 1623 * XXX Does not work if an operand is a constant expression. Constant 1624 * expressions are already folded. 1625 */ 1626 static void 1627 check_precedence_confusion(tnode_t *tn) 1628 { 1629 tnode_t *ln, *rn; 1630 1631 if (!hflag) 1632 return; 1633 1634 debug_node(tn); 1635 1636 lint_assert(is_binary(tn)); 1637 for (ln = tn->u.ops.left; ln->tn_op == CVT; ln = ln->u.ops.left) 1638 continue; 1639 for (rn = tn->u.ops.right; rn->tn_op == CVT; rn = rn->u.ops.left) 1640 continue; 1641 1642 if (is_confusing_precedence(tn->tn_op, 1643 ln->tn_op, ln->tn_parenthesized, 1644 rn->tn_op, rn->tn_parenthesized)) { 1645 /* precedence confusion possible: parenthesize! */ 1646 warning(169); 1647 } 1648 } 1649 1650 static tnode_t * 1651 fold_constant_compare_zero(tnode_t *tn) 1652 { 1653 1654 val_t *v = xcalloc(1, sizeof(*v)); 1655 v->v_tspec = tn->tn_type->t_tspec; 1656 lint_assert(v->v_tspec == INT || (Tflag && v->v_tspec == BOOL)); 1657 1658 lint_assert(has_operands(tn)); 1659 bool l = constant_is_nonzero(tn->u.ops.left); 1660 bool r = is_binary(tn) && constant_is_nonzero(tn->u.ops.right); 1661 1662 switch (tn->tn_op) { 1663 case NOT: 1664 if (hflag && !suppress_constcond) 1665 /* constant operand to '!' */ 1666 warning(239); 1667 v->u.integer = !l ? 1 : 0; 1668 break; 1669 case LOGAND: 1670 v->u.integer = l && r ? 1 : 0; 1671 break; 1672 case LOGOR: 1673 v->u.integer = l || r ? 1 : 0; 1674 break; 1675 default: 1676 lint_assert(/*CONSTCOND*/false); 1677 } 1678 1679 return build_constant(tn->tn_type, v); 1680 } 1681 1682 static long double 1683 floating_error_value(tspec_t t, long double lv) 1684 { 1685 if (t == FLOAT) 1686 return lv < 0 ? -FLT_MAX : FLT_MAX; 1687 if (t == DOUBLE) 1688 return lv < 0 ? -DBL_MAX : DBL_MAX; 1689 /* 1690 * When NetBSD is cross-built in MKLINT=yes mode on x86_64 for sparc64, 1691 * tools/lint checks this code while building usr.bin/xlint. In that 1692 * situation, lint uses the preprocessor for sparc64, in which the type 1693 * 'long double' is IEEE-754-binary128, affecting the macro LDBL_MAX 1694 * below. The type 'long double', as well as the strtold 1695 * implementation, comes from the host platform x86_64 though, where 1696 * 'long double' consumes 128 bits as well but only uses 80 of them. 1697 * The exponent range of the two 'long double' types is the same, but 1698 * the maximum finite value differs due to the extended precision on 1699 * sparc64. 1700 * 1701 * To properly handle the data types of the target platform, lint would 1702 * have to implement the floating-point types in a platform-independent 1703 * way, which is not worth the effort, given how few programs 1704 * practically use 'long double'. 1705 */ 1706 /* LINTED 248: floating-point constant out of range */ 1707 long double max = LDBL_MAX; 1708 return lv < 0 ? -max : max; 1709 } 1710 1711 static bool 1712 is_floating_overflow(tspec_t t, long double val) 1713 { 1714 if (fpe != 0 || isfinite(val) == 0) 1715 return true; 1716 if (t == FLOAT && (val > FLT_MAX || val < -FLT_MAX)) 1717 return true; 1718 if (t == DOUBLE && (val > DBL_MAX || val < -DBL_MAX)) 1719 return true; 1720 return false; 1721 } 1722 1723 static tnode_t * 1724 fold_constant_floating(tnode_t *tn) 1725 { 1726 1727 fpe = 0; 1728 1729 tspec_t t = tn->tn_type->t_tspec; 1730 1731 val_t *v = xcalloc(1, sizeof(*v)); 1732 v->v_tspec = t; 1733 1734 lint_assert(is_floating(t)); 1735 lint_assert(has_operands(tn)); 1736 lint_assert(t == tn->u.ops.left->tn_type->t_tspec); 1737 lint_assert(!is_binary(tn) || t == tn->u.ops.right->tn_type->t_tspec); 1738 1739 long double lv = tn->u.ops.left->u.value.u.floating; 1740 long double rv = is_binary(tn) ? tn->u.ops.right->u.value.u.floating 1741 : 0.0; 1742 1743 switch (tn->tn_op) { 1744 case UPLUS: 1745 v->u.floating = lv; 1746 break; 1747 case UMINUS: 1748 v->u.floating = -lv; 1749 break; 1750 case MULT: 1751 v->u.floating = lv * rv; 1752 break; 1753 case DIV: 1754 if (rv == 0.0) { 1755 /* division by 0 */ 1756 error(139); 1757 v->u.floating = floating_error_value(t, lv); 1758 } else { 1759 v->u.floating = lv / rv; 1760 } 1761 break; 1762 case PLUS: 1763 v->u.floating = lv + rv; 1764 break; 1765 case MINUS: 1766 v->u.floating = lv - rv; 1767 break; 1768 case LT: 1769 v->u.integer = lv < rv ? 1 : 0; 1770 break; 1771 case LE: 1772 v->u.integer = lv <= rv ? 1 : 0; 1773 break; 1774 case GE: 1775 v->u.integer = lv >= rv ? 1 : 0; 1776 break; 1777 case GT: 1778 v->u.integer = lv > rv ? 1 : 0; 1779 break; 1780 case EQ: 1781 v->u.integer = lv == rv ? 1 : 0; 1782 break; 1783 case NE: 1784 v->u.integer = lv != rv ? 1 : 0; 1785 break; 1786 default: 1787 lint_assert(/*CONSTCOND*/false); 1788 } 1789 1790 // XXX: Must not access u.floating after setting u.integer. 1791 lint_assert(fpe != 0 || isnan(v->u.floating) == 0); 1792 if (is_complex(v->v_tspec)) { 1793 /* 1794 * Don't warn, as lint doesn't model the imaginary part of 1795 * complex numbers. 1796 */ 1797 fpe = 0; 1798 } else if (is_floating_overflow(t, v->u.floating)) { 1799 /* operator '%s' produces floating point overflow */ 1800 warning(142, op_name(tn->tn_op)); 1801 v->u.floating = floating_error_value(t, v->u.floating); 1802 fpe = 0; 1803 } 1804 1805 return build_constant(tn->tn_type, v); 1806 } 1807 1808 static void 1809 use(const tnode_t *tn) 1810 { 1811 if (tn == NULL) 1812 return; 1813 switch (tn->tn_op) { 1814 case NAME: 1815 mark_as_used(tn->u.sym, false /* XXX */, false /* XXX */); 1816 break; 1817 case CON: 1818 case STRING: 1819 break; 1820 case CALL:; 1821 const function_call *call = tn->u.call; 1822 for (size_t i = 0, n = call->args_len; i < n; i++) 1823 use(call->args[i]); 1824 break; 1825 default: 1826 lint_assert(has_operands(tn)); 1827 use(tn->u.ops.left); 1828 if (is_binary(tn)) 1829 use(tn->u.ops.right); 1830 } 1831 } 1832 1833 /* 1834 * Create a tree node for a binary operator and its two operands. Also called 1835 * for unary operators; in that case rn is NULL. 1836 * 1837 * Function calls, sizeof and casts are handled elsewhere. 1838 */ 1839 tnode_t * 1840 build_binary(tnode_t *ln, op_t op, bool sys, tnode_t *rn) 1841 { 1842 const mod_t *mp = &modtab[op]; 1843 1844 /* If there was an error in one of the operands, return. */ 1845 if (ln == NULL || (mp->m_binary && rn == NULL)) 1846 return NULL; 1847 1848 if (mp->m_value_context || mp->m_compares_with_zero) 1849 ln = cconv(ln); 1850 if (mp->m_binary && op != ARROW && op != POINT) 1851 rn = cconv(rn); 1852 1853 if (mp->m_comparison) 1854 check_integer_comparison(op, ln, rn); 1855 1856 if (mp->m_value_context || mp->m_compares_with_zero) 1857 ln = promote(op, false, ln); 1858 if (mp->m_binary && op != ARROW && op != POINT && 1859 op != ASSIGN && op != RETURN && op != INIT) 1860 rn = promote(op, false, rn); 1861 1862 if (mp->m_warn_if_left_unsigned_in_c90 && 1863 ln->tn_op == CON && ln->u.value.v_unsigned_since_c90) { 1864 /* C90 treats constant as unsigned, op '%s' */ 1865 warning(218, op_name(op)); 1866 ln->u.value.v_unsigned_since_c90 = false; 1867 } 1868 if (mp->m_warn_if_right_unsigned_in_c90 && 1869 rn->tn_op == CON && rn->u.value.v_unsigned_since_c90) { 1870 /* C90 treats constant as unsigned, op '%s' */ 1871 warning(218, op_name(op)); 1872 rn->u.value.v_unsigned_since_c90 = false; 1873 } 1874 1875 if (mp->m_balance_operands || (!allow_c90 && (op == SHL || op == SHR))) 1876 balance(op, &ln, &rn); 1877 1878 if (!typeok(op, 0, ln, rn)) 1879 return NULL; 1880 1881 tnode_t *ntn; 1882 switch (op) { 1883 case POINT: 1884 case ARROW: 1885 ntn = build_struct_access(op, sys, ln, rn); 1886 break; 1887 case NOT: 1888 if (ln->tn_op == ASSIGN && ln->u.ops.right->tn_op == CON) { 1889 /* constant assignment of type '%s' in operand ... */ 1890 warning(382, type_name(ln->tn_type), 1891 is_nonzero_val(&ln->u.ops.right->u.value) 1892 ? "true" : "false"); 1893 } 1894 ntn = build_op(op, sys, gettyp(Tflag ? BOOL : INT), ln, NULL); 1895 break; 1896 case INCAFT: 1897 case DECAFT: 1898 case INCBEF: 1899 case DECBEF: 1900 ntn = build_prepost_incdec(op, sys, ln); 1901 break; 1902 case ADDR: 1903 ntn = build_address(sys, ln, false); 1904 break; 1905 case INDIR: 1906 ntn = build_op(INDIR, sys, ln->tn_type->t_subt, ln, NULL); 1907 break; 1908 case PLUS: 1909 case MINUS: 1910 ntn = build_plus_minus(op, sys, ln, rn); 1911 break; 1912 case SHL: 1913 case SHR: 1914 ntn = build_bit_shift(op, sys, ln, rn); 1915 break; 1916 case COLON: 1917 ntn = build_colon(sys, ln, rn); 1918 break; 1919 case ASSIGN: 1920 case MULASS: 1921 case DIVASS: 1922 case MODASS: 1923 case ADDASS: 1924 case SUBASS: 1925 case SHLASS: 1926 case SHRASS: 1927 case ANDASS: 1928 case XORASS: 1929 case ORASS: 1930 case RETURN: 1931 case INIT: 1932 ntn = build_assignment(op, sys, ln, rn); 1933 break; 1934 case COMMA: 1935 /* comma operator with types '%s' and '%s' */ 1936 query_message(12, 1937 type_name(ln->tn_type), type_name(rn->tn_type)); 1938 /* FALLTHROUGH */ 1939 case QUEST: 1940 ntn = build_op(op, sys, rn->tn_type, ln, rn); 1941 break; 1942 case REAL: 1943 case IMAG: 1944 ntn = build_real_imag(op, sys, ln); 1945 break; 1946 default: 1947 lint_assert(mp->m_binary == (rn != NULL)); 1948 type_t *rettp = mp->m_returns_bool 1949 ? gettyp(Tflag ? BOOL : INT) : ln->tn_type; 1950 ntn = build_op(op, sys, rettp, ln, rn); 1951 break; 1952 } 1953 1954 if (ntn == NULL) 1955 return NULL; 1956 1957 if (mp->m_possible_precedence_confusion) 1958 check_precedence_confusion(ntn); 1959 1960 if (hflag && !suppress_constcond && 1961 mp->m_compares_with_zero && 1962 (ln->tn_op == CON || 1963 (mp->m_binary && op != QUEST && rn->tn_op == CON)) && 1964 /* XXX: rn->tn_system_dependent should be checked as well */ 1965 !ln->tn_system_dependent) 1966 /* constant in conditional context */ 1967 warning(161); 1968 1969 if (mp->m_fold_constant_operands && ln->tn_op == CON) { 1970 if (!mp->m_binary || rn->tn_op == CON) { 1971 if (mp->m_compares_with_zero) 1972 ntn = fold_constant_compare_zero(ntn); 1973 else if (is_floating(ntn->tn_type->t_tspec)) 1974 ntn = fold_constant_floating(ntn); 1975 else 1976 ntn = fold_constant_integer(ntn); 1977 } else if (op == QUEST) { 1978 lint_assert(has_operands(rn)); 1979 use(ln->u.value.u.integer != 0 1980 ? rn->u.ops.right : rn->u.ops.left); 1981 ntn = ln->u.value.u.integer != 0 1982 ? rn->u.ops.left : rn->u.ops.right; 1983 } 1984 } 1985 1986 return ntn; 1987 } 1988 1989 tnode_t * 1990 build_unary(op_t op, bool sys, tnode_t *tn) 1991 { 1992 return build_binary(tn, op, sys, NULL); 1993 } 1994 1995 static bool 1996 are_members_compatible(const sym_t *a, const sym_t *b) 1997 { 1998 if (a->u.s_member.sm_offset_in_bits != b->u.s_member.sm_offset_in_bits) 1999 return false; 2000 2001 const type_t *atp = a->s_type; 2002 const type_t *btp = b->s_type; 2003 bool w = false; 2004 if (!types_compatible(atp, btp, false, false, &w) && !w) 2005 return false; 2006 if (a->s_bitfield != b->s_bitfield) 2007 return false; 2008 if (a->s_bitfield) { 2009 if (atp->t_bit_field_width != btp->t_bit_field_width) 2010 return false; 2011 if (atp->t_bit_field_offset != btp->t_bit_field_offset) 2012 return false; 2013 } 2014 return true; 2015 } 2016 2017 /* 2018 * Return whether all struct/union members with the same name have the same 2019 * type and offset. 2020 */ 2021 static bool 2022 all_members_compatible(const sym_t *msym) 2023 { 2024 for (const sym_t *csym = msym; 2025 csym != NULL; csym = csym->s_symtab_next) { 2026 if (!is_member(csym)) 2027 continue; 2028 if (strcmp(msym->s_name, csym->s_name) != 0) 2029 continue; 2030 2031 for (const sym_t *sym = csym->s_symtab_next; 2032 sym != NULL; sym = sym->s_symtab_next) { 2033 if (is_member(sym) 2034 && strcmp(csym->s_name, sym->s_name) == 0 2035 && !are_members_compatible(csym, sym)) 2036 return false; 2037 } 2038 } 2039 return true; 2040 } 2041 2042 sym_t * 2043 find_member(const struct_or_union *sou, const char *name) 2044 { 2045 for (sym_t *mem = sou->sou_first_member; 2046 mem != NULL; mem = mem->s_next) { 2047 lint_assert(is_member(mem)); 2048 lint_assert(mem->u.s_member.sm_containing_type == sou); 2049 if (strcmp(mem->s_name, name) == 0) 2050 return mem; 2051 } 2052 2053 for (sym_t *mem = sou->sou_first_member; 2054 mem != NULL; mem = mem->s_next) { 2055 if (is_struct_or_union(mem->s_type->t_tspec) 2056 && mem->s_name == unnamed) { 2057 sym_t *nested_mem = 2058 find_member(mem->s_type->u.sou, name); 2059 if (nested_mem != NULL) 2060 return nested_mem; 2061 } 2062 } 2063 return NULL; 2064 } 2065 2066 /* 2067 * Remove the member if it was unknown until now, which means 2068 * that no defined struct or union has a member with the same name. 2069 */ 2070 static void 2071 remove_unknown_member(tnode_t *tn, sym_t *msym) 2072 { 2073 /* type '%s' does not have member '%s' */ 2074 error(101, type_name(tn->tn_type), msym->s_name); 2075 symtab_remove_forever(msym); 2076 msym->s_kind = SK_MEMBER; 2077 msym->s_scl = STRUCT_MEMBER; 2078 2079 struct_or_union *sou = expr_zero_alloc(sizeof(*sou), 2080 "struct_or_union"); 2081 sou->sou_tag = expr_zero_alloc(sizeof(*sou->sou_tag), "sym"); 2082 sou->sou_tag->s_name = unnamed; 2083 2084 msym->u.s_member.sm_containing_type = sou; 2085 /* 2086 * The member sm_offset_in_bits is not needed here since this symbol 2087 * can only be used for error reporting. 2088 */ 2089 } 2090 2091 /* 2092 * Returns a symbol which has the same name as 'msym' and is a member of the 2093 * struct or union specified by 'tn'. 2094 */ 2095 static sym_t * 2096 struct_or_union_member(tnode_t *tn, op_t op, sym_t *msym) 2097 { 2098 2099 /* Determine the tag type of which msym is expected to be a member. */ 2100 const type_t *tp = NULL; 2101 if (op == POINT && is_struct_or_union(tn->tn_type->t_tspec)) 2102 tp = tn->tn_type; 2103 if (op == ARROW && tn->tn_type->t_tspec == PTR 2104 && is_struct_or_union(tn->tn_type->t_subt->t_tspec)) 2105 tp = tn->tn_type->t_subt; 2106 struct_or_union *sou = tp != NULL ? tp->u.sou : NULL; 2107 2108 if (sou != NULL) { 2109 sym_t *nested_mem = find_member(sou, msym->s_name); 2110 if (nested_mem != NULL) 2111 return nested_mem; 2112 } 2113 2114 if (msym->s_scl == NO_SCL) { 2115 remove_unknown_member(tn, msym); 2116 return msym; 2117 } 2118 2119 bool eq = all_members_compatible(msym); 2120 2121 /* 2122 * Now handle the case in which the left operand refers really to a 2123 * struct/union, but the right operand is not member of it. 2124 */ 2125 if (sou != NULL) { 2126 if (eq && !allow_c90) 2127 /* illegal use of member '%s' */ 2128 warning(102, msym->s_name); 2129 else 2130 /* illegal use of member '%s' */ 2131 error(102, msym->s_name); 2132 return msym; 2133 } 2134 2135 if (eq) { 2136 if (op == POINT) { 2137 if (!allow_c90) 2138 /* left operand of '.' must be struct ... */ 2139 warning(103, type_name(tn->tn_type)); 2140 else 2141 /* left operand of '.' must be struct ... */ 2142 error(103, type_name(tn->tn_type)); 2143 } else { 2144 if (!allow_c90 && tn->tn_type->t_tspec == PTR) 2145 /* left operand of '->' must be pointer ... */ 2146 warning(104, type_name(tn->tn_type)); 2147 else 2148 /* left operand of '->' must be pointer ... */ 2149 error(104, type_name(tn->tn_type)); 2150 } 2151 } else { 2152 if (!allow_c90) 2153 /* non-unique member requires struct/union %s */ 2154 error(105, op == POINT ? "object" : "pointer"); 2155 else 2156 /* unacceptable operand of '%s' */ 2157 error(111, op_name(op)); 2158 } 2159 2160 return msym; 2161 } 2162 2163 tnode_t * 2164 build_member_access(tnode_t *ln, op_t op, bool sys, sbuf_t *member) 2165 { 2166 sym_t *msym; 2167 2168 if (ln == NULL) 2169 return NULL; 2170 2171 if (op == ARROW) 2172 /* must do this before struct_or_union_member is called */ 2173 ln = cconv(ln); 2174 msym = struct_or_union_member(ln, op, getsym(member)); 2175 return build_binary(ln, op, sys, build_name(msym, false)); 2176 } 2177 2178 /* 2179 * Perform class conversions. 2180 * 2181 * Arrays of type T are converted into pointers to type T. 2182 * Functions are converted to pointers to functions. 2183 * Lvalues are converted to rvalues. 2184 * 2185 * C99 6.3 "Conversions" 2186 * C99 6.3.2 "Other operands" 2187 * C99 6.3.2.1 "Lvalues, arrays, and function designators" 2188 */ 2189 tnode_t * 2190 cconv(tnode_t *tn) 2191 { 2192 if (tn->tn_type->t_tspec == ARRAY) { 2193 if (!tn->tn_lvalue) { 2194 /* XXX print correct operator */ 2195 /* %soperand of '%s' must be lvalue */ 2196 gnuism(114, "", op_name(ADDR)); 2197 } 2198 tn = build_op(ADDR, tn->tn_sys, 2199 expr_derive_type(tn->tn_type->t_subt, PTR), tn, NULL); 2200 } 2201 2202 if (tn->tn_type->t_tspec == FUNC) 2203 tn = build_address(tn->tn_sys, tn, true); 2204 2205 if (tn->tn_lvalue) { 2206 type_t *tp = expr_dup_type(tn->tn_type); 2207 /* C99 6.3.2.1p2 sentence 2 says to remove the qualifiers. */ 2208 tp->t_const = tp->t_volatile = false; 2209 tn = build_op(LOAD, tn->tn_sys, tp, tn, NULL); 2210 } 2211 2212 return tn; 2213 } 2214 2215 const tnode_t * 2216 before_conversion(const tnode_t *tn) 2217 { 2218 while (tn->tn_op == CVT && !tn->tn_cast) 2219 tn = tn->u.ops.left; 2220 return tn; 2221 } 2222 2223 /* 2224 * Most errors required by C90 are reported in struct_or_union_member(). 2225 * Here we only check for totally wrong things. 2226 */ 2227 static bool 2228 typeok_point(const tnode_t *ln, const type_t *ltp, tspec_t lt) 2229 { 2230 if (is_struct_or_union(lt)) 2231 return true; 2232 2233 if (lt == FUNC || lt == VOID || ltp->t_bitfield) 2234 goto wrong; 2235 2236 /* 2237 * Some C dialects from before C90 tolerated any lvalue on the 2238 * left-hand side of the '.' operator, allowing things like 'char 2239 * st[100]; st.st_mtime', assuming that the member 'st_mtime' only 2240 * occurred in a single struct; see typeok_arrow. 2241 */ 2242 if (ln->tn_lvalue) 2243 return true; 2244 2245 wrong: 2246 /* With allow_c90 we already got an error */ 2247 if (!allow_c90) 2248 /* unacceptable operand of '%s' */ 2249 error(111, op_name(POINT)); 2250 2251 return false; 2252 } 2253 2254 static bool 2255 typeok_arrow(tspec_t lt) 2256 { 2257 /* 2258 * C1978 Appendix A 14.1 says: <quote>In fact, any lvalue is allowed 2259 * before '.', and that lvalue is then assumed to have the form of the 2260 * structure of which the name of the right is a member. [...] Such 2261 * constructions are non-portable.</quote> 2262 */ 2263 if (lt == PTR || (!allow_c90 && is_integer(lt))) 2264 return true; 2265 2266 /* With allow_c90 we already got an error */ 2267 if (!allow_c90) 2268 /* unacceptable operand of '%s' */ 2269 error(111, op_name(ARROW)); 2270 return false; 2271 } 2272 2273 static bool 2274 typeok_incdec(op_t op, const tnode_t *tn, const type_t *tp) 2275 { 2276 /* operand has scalar type (checked in typeok) */ 2277 if (!tn->tn_lvalue) { 2278 if (tn->tn_op == CVT && tn->tn_cast && 2279 tn->u.ops.left->tn_op == LOAD) 2280 /* a cast does not yield an lvalue */ 2281 error(163); 2282 /* %soperand of '%s' must be lvalue */ 2283 error(114, "", op_name(op)); 2284 return false; 2285 } 2286 if (tp->t_const && allow_c90) 2287 /* %soperand of '%s' must be modifiable lvalue */ 2288 warning(115, "", op_name(op)); 2289 return true; 2290 } 2291 2292 static bool 2293 typeok_address(op_t op, const tnode_t *tn, const type_t *tp, tspec_t t) 2294 { 2295 if (t == ARRAY || t == FUNC) { 2296 /* ok, a warning comes later (in build_address()) */ 2297 } else if (!tn->tn_lvalue) { 2298 if (tn->tn_op == CVT && tn->tn_cast && 2299 tn->u.ops.left->tn_op == LOAD) 2300 /* a cast does not yield an lvalue */ 2301 error(163); 2302 /* %soperand of '%s' must be lvalue */ 2303 error(114, "", op_name(op)); 2304 return false; 2305 } else if (is_scalar(t)) { 2306 if (tp->t_bitfield) { 2307 /* cannot take address of bit-field */ 2308 error(112); 2309 return false; 2310 } 2311 } else if (t != STRUCT && t != UNION) { 2312 /* unacceptable operand of '%s' */ 2313 error(111, op_name(op)); 2314 return false; 2315 } 2316 if (tn->tn_op == NAME && tn->u.sym->s_register) { 2317 /* cannot take address of register '%s' */ 2318 error(113, tn->u.sym->s_name); 2319 return false; 2320 } 2321 return true; 2322 } 2323 2324 static bool 2325 typeok_indir(const type_t *tp, tspec_t t) 2326 { 2327 2328 if (t != PTR) { 2329 /* cannot dereference non-pointer type '%s' */ 2330 error(96, type_name(tp)); 2331 return false; 2332 } 2333 return true; 2334 } 2335 2336 static void 2337 warn_incompatible_types(op_t op, 2338 const type_t *ltp, tspec_t lt, 2339 const type_t *rtp, tspec_t rt) 2340 { 2341 bool binary = modtab[op].m_binary; 2342 2343 if (lt == VOID || (binary && rt == VOID)) { 2344 /* void type illegal in expression */ 2345 error(109); 2346 } else if (op == ASSIGN) 2347 /* cannot assign to '%s' from '%s' */ 2348 error(171, type_name(ltp), type_name(rtp)); 2349 else if (binary) 2350 /* operands of '%s' have incompatible types '%s' and '%s' */ 2351 error(107, op_name(op), type_name(ltp), type_name(rtp)); 2352 else { 2353 lint_assert(rt == NO_TSPEC); 2354 /* operand of '%s' has invalid type '%s' */ 2355 error(108, op_name(op), type_name(ltp)); 2356 } 2357 } 2358 2359 static bool 2360 typeok_plus(op_t op, 2361 const type_t *ltp, tspec_t lt, 2362 const type_t *rtp, tspec_t rt) 2363 { 2364 /* operands have scalar types (checked in typeok) */ 2365 if ((lt == PTR && !is_integer(rt)) || (rt == PTR && !is_integer(lt))) { 2366 warn_incompatible_types(op, ltp, lt, rtp, rt); 2367 return false; 2368 } 2369 return true; 2370 } 2371 2372 static bool 2373 typeok_minus(op_t op, 2374 const type_t *ltp, tspec_t lt, 2375 const type_t *rtp, tspec_t rt) 2376 { 2377 /* operands have scalar types (checked in typeok) */ 2378 if ((lt == PTR && rt != PTR && !is_integer(rt)) || 2379 (lt != PTR && rt == PTR)) { 2380 warn_incompatible_types(op, ltp, lt, rtp, rt); 2381 return false; 2382 } 2383 if (lt == PTR && rt == PTR && 2384 !types_compatible(ltp->t_subt, rtp->t_subt, true, false, NULL)) { 2385 /* illegal pointer subtraction */ 2386 error(116); 2387 } 2388 return true; 2389 } 2390 2391 static void 2392 typeok_shr(op_t op, 2393 const tnode_t *ln, tspec_t lt, 2394 const tnode_t *rn, tspec_t rt) 2395 { 2396 tspec_t olt = before_conversion(ln)->tn_type->t_tspec; 2397 tspec_t ort = before_conversion(rn)->tn_type->t_tspec; 2398 2399 /* operands have integer types (checked in typeok) */ 2400 if (pflag && !is_uinteger(olt)) { 2401 integer_constraints lc = ic_expr(ln); 2402 if (!ic_maybe_signed(ln->tn_type, &lc)) 2403 return; 2404 2405 if (ln->tn_op != CON) 2406 /* bitwise '%s' on signed value possibly nonportable */ 2407 warning(117, op_name(op)); 2408 else if (ln->u.value.u.integer < 0) 2409 /* bitwise '%s' on signed value nonportable */ 2410 warning(120, op_name(op)); 2411 } else if (allow_trad && allow_c90 && 2412 !is_uinteger(olt) && is_uinteger(ort)) { 2413 /* The left operand would become unsigned in traditional C. */ 2414 if (hflag && (ln->tn_op != CON || ln->u.value.u.integer < 0)) { 2415 /* semantics of '%s' change in C90; use ... */ 2416 warning(118, op_name(op)); 2417 } 2418 } else if (allow_trad && allow_c90 && 2419 !is_uinteger(olt) && !is_uinteger(ort) && 2420 portable_rank_cmp(lt, rt) < 0) { 2421 /* 2422 * In traditional C, the left operand would be extended 2423 * (possibly sign-extended) and then shifted. 2424 */ 2425 if (hflag && (ln->tn_op != CON || ln->u.value.u.integer < 0)) { 2426 /* semantics of '%s' change in C90; use ... */ 2427 warning(118, op_name(op)); 2428 } 2429 } 2430 } 2431 2432 static void 2433 typeok_shl(op_t op, tspec_t lt, tspec_t rt) 2434 { 2435 /* 2436 * C90 does not perform balancing for shift operations, but traditional 2437 * C does. If the width of the right operand is greater than the width 2438 * of the left operand, then in traditional C the left operand would be 2439 * extended to the width of the right operand. For SHL this may result 2440 * in different results. 2441 */ 2442 if (portable_rank_cmp(lt, rt) < 0) { 2443 /* 2444 * XXX If both operands are constant, make sure that there is 2445 * really a difference between C90 and traditional C. 2446 */ 2447 if (hflag && allow_trad && allow_c90) 2448 /* semantics of '%s' change in C90; use ... */ 2449 warning(118, op_name(op)); 2450 } 2451 } 2452 2453 static void 2454 typeok_shift(const type_t *ltp, tspec_t lt, const tnode_t *rn, tspec_t rt) 2455 { 2456 if (rn->tn_op != CON) 2457 return; 2458 2459 if (!is_uinteger(rt) && rn->u.value.u.integer < 0) 2460 /* negative shift */ 2461 warning(121); 2462 else if ((uint64_t)rn->u.value.u.integer == size_in_bits(lt)) 2463 /* shift amount %u equals bit-size of '%s' */ 2464 warning(267, (unsigned)rn->u.value.u.integer, type_name(ltp)); 2465 else if ((uint64_t)rn->u.value.u.integer > size_in_bits(lt)) { 2466 /* shift amount %llu is greater than bit-size %llu of '%s' */ 2467 warning(122, (unsigned long long)rn->u.value.u.integer, 2468 (unsigned long long)size_in_bits(lt), 2469 tspec_name(lt)); 2470 } 2471 } 2472 2473 static bool 2474 is_typeok_eq(const tnode_t *ln, tspec_t lt, const tnode_t *rn, tspec_t rt) 2475 { 2476 if (lt == PTR && is_null_pointer(rn)) 2477 return true; 2478 if (rt == PTR && is_null_pointer(ln)) 2479 return true; 2480 return false; 2481 } 2482 2483 static void 2484 warn_incompatible_pointers(op_t op, const type_t *ltp, const type_t *rtp) 2485 { 2486 lint_assert(ltp->t_tspec == PTR); 2487 lint_assert(rtp->t_tspec == PTR); 2488 2489 tspec_t lt = ltp->t_subt->t_tspec; 2490 tspec_t rt = rtp->t_subt->t_tspec; 2491 2492 if (is_struct_or_union(lt) && is_struct_or_union(rt)) { 2493 if (op == RETURN) 2494 /* illegal structure pointer combination */ 2495 warning(244); 2496 else { 2497 /* incompatible structure pointers: '%s' '%s' '%s' */ 2498 warning(245, type_name(ltp), 2499 op_name(op), type_name(rtp)); 2500 } 2501 } else { 2502 if (op == RETURN) 2503 /* illegal combination of '%s' and '%s' */ 2504 warning(184, type_name(ltp), type_name(rtp)); 2505 else { 2506 /* illegal combination of '%s' and '%s', op '%s' */ 2507 warning(124, 2508 type_name(ltp), type_name(rtp), op_name(op)); 2509 } 2510 } 2511 } 2512 2513 static void 2514 check_pointer_comparison(op_t op, const tnode_t *ln, const tnode_t *rn) 2515 { 2516 type_t *ltp = ln->tn_type, *rtp = rn->tn_type; 2517 tspec_t lst = ltp->t_subt->t_tspec, rst = rtp->t_subt->t_tspec; 2518 2519 if (lst == VOID || rst == VOID) { 2520 /* TODO: C99 behaves like C90 here. */ 2521 if (!allow_trad && !allow_c99 && 2522 (lst == FUNC || rst == FUNC)) { 2523 /* (void *)0 is already handled in typeok() */ 2524 const char *lsts, *rsts; 2525 *(lst == FUNC ? &lsts : &rsts) = "function pointer"; 2526 *(lst == VOID ? &lsts : &rsts) = "'void *'"; 2527 /* C90 or later forbid comparison of %s with %s */ 2528 warning(274, lsts, rsts); 2529 } 2530 return; 2531 } 2532 2533 if (!types_compatible(ltp->t_subt, rtp->t_subt, true, false, NULL)) { 2534 warn_incompatible_pointers(op, ltp, rtp); 2535 return; 2536 } 2537 2538 if (lst == FUNC && rst == FUNC) { 2539 /* TODO: C99 behaves like C90 here, see C99 6.5.8p2. */ 2540 if (!allow_trad && !allow_c99 && op != EQ && op != NE) 2541 /* pointers to functions can only be compared ... */ 2542 warning(125); 2543 } 2544 } 2545 2546 static bool 2547 typeok_compare(op_t op, 2548 const tnode_t *ln, const type_t *ltp, tspec_t lt, 2549 const tnode_t *rn, const type_t *rtp, tspec_t rt) 2550 { 2551 if (lt == PTR && rt == PTR) { 2552 check_pointer_comparison(op, ln, rn); 2553 return true; 2554 } 2555 2556 if (lt != PTR && rt != PTR) 2557 return true; 2558 2559 if (!is_integer(lt) && !is_integer(rt)) { 2560 warn_incompatible_types(op, ltp, lt, rtp, rt); 2561 return false; 2562 } 2563 2564 const char *lx = lt == PTR ? "pointer" : "integer"; 2565 const char *rx = rt == PTR ? "pointer" : "integer"; 2566 /* illegal combination of %s '%s' and %s '%s', op '%s' */ 2567 warning(123, lx, type_name(ltp), rx, type_name(rtp), op_name(op)); 2568 return true; 2569 } 2570 2571 static bool 2572 typeok_quest(tspec_t lt, const tnode_t *rn) 2573 { 2574 if (!is_scalar(lt)) { 2575 /* first operand of '?' must have scalar type */ 2576 error(170); 2577 return false; 2578 } 2579 lint_assert(before_conversion(rn)->tn_op == COLON); 2580 return true; 2581 } 2582 2583 static void 2584 typeok_colon_pointer(const type_t *ltp, const type_t *rtp) 2585 { 2586 type_t *lstp = ltp->t_subt; 2587 type_t *rstp = rtp->t_subt; 2588 tspec_t lst = lstp->t_tspec; 2589 tspec_t rst = rstp->t_tspec; 2590 2591 if ((lst == VOID && rst == FUNC) || (lst == FUNC && rst == VOID)) { 2592 /* (void *)0 is handled in typeok_colon */ 2593 /* TODO: C99 behaves like C90 here. */ 2594 if (!allow_trad && !allow_c99) 2595 /* conversion of %s to %s requires a cast, op %s */ 2596 warning(305, "function pointer", "'void *'", 2597 op_name(COLON)); 2598 return; 2599 } 2600 2601 if (pointer_types_are_compatible(lstp, rstp, true)) 2602 return; 2603 if (!types_compatible(lstp, rstp, true, false, NULL)) 2604 warn_incompatible_pointers(COLON, ltp, rtp); 2605 } 2606 2607 static bool 2608 typeok_colon(const tnode_t *ln, const type_t *ltp, tspec_t lt, 2609 const tnode_t *rn, const type_t *rtp, tspec_t rt) 2610 { 2611 2612 if (is_arithmetic(lt) && is_arithmetic(rt)) 2613 return true; 2614 if (lt == BOOL && rt == BOOL) 2615 return true; 2616 2617 if (lt == STRUCT && rt == STRUCT && ltp->u.sou == rtp->u.sou) 2618 return true; 2619 if (lt == UNION && rt == UNION && ltp->u.sou == rtp->u.sou) 2620 return true; 2621 2622 if (lt == PTR && is_null_pointer(rn)) 2623 return true; 2624 if (rt == PTR && is_null_pointer(ln)) 2625 return true; 2626 2627 if ((lt == PTR && is_integer(rt)) || (is_integer(lt) && rt == PTR)) { 2628 const char *lx = lt == PTR ? "pointer" : "integer"; 2629 const char *rx = rt == PTR ? "pointer" : "integer"; 2630 /* illegal combination of %s '%s' and %s '%s', op '%s' */ 2631 warning(123, lx, type_name(ltp), 2632 rx, type_name(rtp), op_name(COLON)); 2633 return true; 2634 } 2635 2636 if (lt == VOID || rt == VOID) { 2637 if (lt != VOID || rt != VOID) 2638 /* incompatible types '%s' and '%s' in conditional */ 2639 warning(126, type_name(ltp), type_name(rtp)); 2640 return true; 2641 } 2642 2643 if (lt == PTR && rt == PTR) { 2644 typeok_colon_pointer(ltp, rtp); 2645 return true; 2646 } 2647 2648 /* incompatible types '%s' and '%s' in conditional */ 2649 error(126, type_name(ltp), type_name(rtp)); 2650 return false; 2651 } 2652 2653 static bool 2654 has_constant_member(const type_t *tp) 2655 { 2656 lint_assert(is_struct_or_union(tp->t_tspec)); 2657 2658 for (sym_t *m = tp->u.sou->sou_first_member; 2659 m != NULL; m = m->s_next) { 2660 const type_t *mtp = m->s_type; 2661 if (mtp->t_const) 2662 return true; 2663 if (is_struct_or_union(mtp->t_tspec) && 2664 has_constant_member(mtp)) 2665 return true; 2666 } 2667 return false; 2668 } 2669 2670 static bool 2671 typeok_assign(op_t op, const tnode_t *ln, const type_t *ltp, tspec_t lt) 2672 { 2673 if (op == RETURN || op == INIT || op == FARG) 2674 return true; 2675 2676 if (!ln->tn_lvalue) { 2677 if (ln->tn_op == CVT && ln->tn_cast && 2678 ln->u.ops.left->tn_op == LOAD) 2679 /* a cast does not yield an lvalue */ 2680 error(163); 2681 /* %soperand of '%s' must be lvalue */ 2682 error(114, "left ", op_name(op)); 2683 return false; 2684 } else if (ltp->t_const 2685 || (is_struct_or_union(lt) && has_constant_member(ltp))) { 2686 if (allow_c90) 2687 /* %soperand of '%s' must be modifiable lvalue */ 2688 warning(115, "left ", op_name(op)); 2689 } 2690 return true; 2691 } 2692 2693 static bool 2694 typeok_scalar(op_t op, const mod_t *mp, 2695 const type_t *ltp, tspec_t lt, 2696 const type_t *rtp, tspec_t rt) 2697 { 2698 if (mp->m_takes_bool && lt == BOOL && rt == BOOL) 2699 return true; 2700 if (mp->m_requires_integer) { 2701 if (!is_integer(lt) || (mp->m_binary && !is_integer(rt))) { 2702 warn_incompatible_types(op, ltp, lt, rtp, rt); 2703 return false; 2704 } 2705 } else if (mp->m_requires_integer_or_complex) { 2706 if ((!is_integer(lt) && !is_complex(lt)) || 2707 (mp->m_binary && (!is_integer(rt) && !is_complex(rt)))) { 2708 warn_incompatible_types(op, ltp, lt, rtp, rt); 2709 return false; 2710 } 2711 } else if (mp->m_requires_scalar) { 2712 if (!is_scalar(lt) || (mp->m_binary && !is_scalar(rt))) { 2713 warn_incompatible_types(op, ltp, lt, rtp, rt); 2714 return false; 2715 } 2716 } else if (mp->m_requires_arith) { 2717 if (!is_arithmetic(lt) || 2718 (mp->m_binary && !is_arithmetic(rt))) { 2719 warn_incompatible_types(op, ltp, lt, rtp, rt); 2720 return false; 2721 } 2722 } 2723 return true; 2724 } 2725 2726 static void 2727 check_assign_void_pointer(op_t op, int arg, 2728 tspec_t lt, tspec_t lst, 2729 tspec_t rt, tspec_t rst) 2730 { 2731 2732 if (!(lt == PTR && rt == PTR && (lst == VOID || rst == VOID))) 2733 return; 2734 /* two pointers, at least one pointer to void */ 2735 2736 /* TODO: C99 behaves like C90 here. */ 2737 if (!(!allow_trad && !allow_c99 && (lst == FUNC || rst == FUNC))) 2738 return; 2739 /* comb. of ptr to func and ptr to void */ 2740 2741 const char *lts, *rts; 2742 *(lst == FUNC ? <s : &rts) = "function pointer"; 2743 *(lst == VOID ? <s : &rts) = "'void *'"; 2744 2745 switch (op) { 2746 case INIT: 2747 case RETURN: 2748 /* conversion of %s to %s requires a cast */ 2749 warning(303, rts, lts); 2750 break; 2751 case FARG: 2752 /* conversion of %s to %s requires a cast, arg #%d */ 2753 warning(304, rts, lts, arg); 2754 break; 2755 default: 2756 /* conversion of %s to %s requires a cast, op %s */ 2757 warning(305, rts, lts, op_name(op)); 2758 break; 2759 } 2760 } 2761 2762 static bool 2763 is_direct_function_call(const tnode_t *tn, const char **out_name) 2764 { 2765 2766 if (tn->tn_op == CALL 2767 && tn->u.call->func->tn_op == ADDR 2768 && tn->u.call->func->u.ops.left->tn_op == NAME) { 2769 *out_name = tn->u.call->func->u.ops.left->u.sym->s_name; 2770 return true; 2771 } 2772 return false; 2773 } 2774 2775 static bool 2776 is_unconst_function(const char *name) 2777 { 2778 2779 return strcmp(name, "memchr") == 0 || 2780 strcmp(name, "strchr") == 0 || 2781 strcmp(name, "strpbrk") == 0 || 2782 strcmp(name, "strrchr") == 0 || 2783 strcmp(name, "strstr") == 0; 2784 } 2785 2786 static bool 2787 is_const_char_pointer(const tnode_t *tn) 2788 { 2789 /* 2790 * For traditional reasons, C99 6.4.5p5 defines that string literals 2791 * have type 'char[]'. They are often implicitly converted to 'char 2792 * *', for example when they are passed as function arguments. 2793 * 2794 * C99 6.4.5p6 further defines that modifying a string that is 2795 * constructed from a string literal invokes undefined behavior. 2796 * 2797 * Out of these reasons, string literals are treated as 'effectively 2798 * const' here. 2799 */ 2800 if (tn->tn_op == CVT && 2801 tn->u.ops.left->tn_op == ADDR && 2802 tn->u.ops.left->u.ops.left->tn_op == STRING) 2803 return true; 2804 2805 const type_t *tp = before_conversion(tn)->tn_type; 2806 return tp->t_tspec == PTR && 2807 tp->t_subt->t_tspec == CHAR && 2808 tp->t_subt->t_const; 2809 } 2810 2811 static bool 2812 is_const_pointer(const tnode_t *tn) 2813 { 2814 const type_t *tp = before_conversion(tn)->tn_type; 2815 return tp->t_tspec == PTR && tp->t_subt->t_const; 2816 } 2817 2818 static void 2819 check_unconst_function(const type_t *lstp, const tnode_t *rn) 2820 { 2821 const char *function_name; 2822 2823 if (lstp->t_tspec == CHAR && !lstp->t_const && 2824 is_direct_function_call(rn, &function_name) && 2825 is_unconst_function(function_name) && 2826 rn->u.call->args_len >= 1 && 2827 is_const_char_pointer(rn->u.call->args[0])) { 2828 /* call to '%s' effectively discards 'const' from argument */ 2829 warning(346, function_name); 2830 } 2831 2832 if (!lstp->t_const && 2833 is_direct_function_call(rn, &function_name) && 2834 strcmp(function_name, "bsearch") == 0 && 2835 rn->u.call->args_len >= 2 && 2836 is_const_pointer(rn->u.call->args[1])) { 2837 /* call to '%s' effectively discards 'const' from argument */ 2838 warning(346, function_name); 2839 } 2840 } 2841 2842 static bool 2843 check_assign_void_pointer_compat(op_t op, int arg, 2844 tspec_t lt, 2845 const type_t *lstp, tspec_t lst, 2846 const tnode_t *rn, 2847 const type_t *rtp, tspec_t rt, 2848 const type_t *rstp, tspec_t rst) 2849 { 2850 if (!(lt == PTR && rt == PTR && (lst == VOID || rst == VOID || 2851 types_compatible(lstp, rstp, 2852 true, false, NULL)))) 2853 return false; 2854 2855 /* compatible pointer types (qualifiers ignored) */ 2856 char qualifiers[32]; 2857 snprintf(qualifiers, sizeof(qualifiers), "%s%s", 2858 !lstp->t_const && rstp->t_const ? " const" : "", 2859 !lstp->t_volatile && rstp->t_volatile ? " volatile" : ""); 2860 if (allow_c90 && qualifiers[0] != '\0') { 2861 switch (op) { 2862 case INIT: 2863 case RETURN: 2864 /* '%s' discards '%s' from '%s' */ 2865 warning(182, op_name(op), 2866 qualifiers + 1, type_name(rtp)); 2867 break; 2868 case FARG: 2869 /* passing '%s' to argument %d discards '%s' */ 2870 warning(383, type_name(rtp), arg, qualifiers + 1); 2871 break; 2872 default: 2873 /* operator '%s' discards '%s' from '%s' */ 2874 warning(128, op_name(op), 2875 qualifiers + 1, type_name(rtp)); 2876 break; 2877 } 2878 } 2879 2880 if (allow_c90) 2881 check_unconst_function(lstp, rn); 2882 2883 return true; 2884 } 2885 2886 static bool 2887 check_assign_pointer_integer(op_t op, int arg, 2888 const type_t *ltp, tspec_t lt, 2889 const type_t *rtp, tspec_t rt) 2890 { 2891 2892 if (!((lt == PTR && is_integer(rt)) || (is_integer(lt) && rt == PTR))) 2893 return false; 2894 2895 const char *lx = lt == PTR ? "pointer" : "integer"; 2896 const char *rx = rt == PTR ? "pointer" : "integer"; 2897 2898 switch (op) { 2899 case INIT: 2900 case RETURN: 2901 /* illegal combination of %s '%s' and %s '%s' */ 2902 warning(183, lx, type_name(ltp), rx, type_name(rtp)); 2903 break; 2904 case FARG: 2905 /* illegal combination of %s '%s' and %s '%s', arg #%d */ 2906 warning(154, 2907 lx, type_name(ltp), rx, type_name(rtp), arg); 2908 break; 2909 default: 2910 /* illegal combination of %s '%s' and %s '%s', op '%s' */ 2911 warning(123, 2912 lx, type_name(ltp), rx, type_name(rtp), op_name(op)); 2913 break; 2914 } 2915 return true; 2916 } 2917 2918 static bool 2919 check_assign_pointer(op_t op, int arg, 2920 const type_t *ltp, tspec_t lt, 2921 const type_t *rtp, tspec_t rt) 2922 { 2923 if (!(lt == PTR && rt == PTR)) 2924 return false; 2925 2926 if (op == FARG) 2927 /* converting '%s' to incompatible '%s' for ... */ 2928 warning(153, type_name(rtp), type_name(ltp), arg); 2929 else 2930 warn_incompatible_pointers(op, ltp, rtp); 2931 return true; 2932 } 2933 2934 static void 2935 warn_assign(op_t op, int arg, 2936 const type_t *ltp, tspec_t lt, 2937 const type_t *rtp, tspec_t rt) 2938 { 2939 switch (op) { 2940 case INIT: 2941 /* cannot initialize '%s' from '%s' */ 2942 error(185, type_name(ltp), type_name(rtp)); 2943 break; 2944 case RETURN: 2945 /* function has return type '%s' but returns '%s' */ 2946 error(211, type_name(ltp), type_name(rtp)); 2947 break; 2948 case FARG: 2949 /* passing '%s' to incompatible '%s', arg #%d */ 2950 warning(155, type_name(rtp), type_name(ltp), arg); 2951 break; 2952 default: 2953 warn_incompatible_types(op, ltp, lt, rtp, rt); 2954 break; 2955 } 2956 } 2957 2958 /* 2959 * Checks type compatibility for ASSIGN, INIT, FARG and RETURN 2960 * and prints warnings/errors if necessary. 2961 * Returns whether the types are (almost) compatible. 2962 */ 2963 static bool 2964 check_assign_types_compatible(op_t op, int arg, 2965 const tnode_t *ln, const tnode_t *rn) 2966 { 2967 tspec_t lt, rt, lst = NO_TSPEC, rst = NO_TSPEC; 2968 type_t *ltp, *rtp, *lstp = NULL, *rstp = NULL; 2969 2970 if ((lt = (ltp = ln->tn_type)->t_tspec) == PTR) 2971 lst = (lstp = ltp->t_subt)->t_tspec; 2972 if ((rt = (rtp = rn->tn_type)->t_tspec) == PTR) 2973 rst = (rstp = rtp->t_subt)->t_tspec; 2974 2975 if (lt == BOOL && is_scalar(rt)) /* C99 6.3.1.2 */ 2976 return true; 2977 2978 if (is_arithmetic(lt) && (is_arithmetic(rt) || rt == BOOL)) 2979 return true; 2980 2981 if (is_struct_or_union(lt) && is_struct_or_union(rt)) 2982 return ltp->u.sou == rtp->u.sou; 2983 2984 if (lt == PTR && is_null_pointer(rn)) { 2985 if (is_integer(rn->tn_type->t_tspec)) 2986 /* implicit conversion from integer 0 to pointer ... */ 2987 query_message(15, type_name(ltp)); 2988 return true; 2989 } 2990 2991 check_assign_void_pointer(op, arg, lt, lst, rt, rst); 2992 2993 if (check_assign_void_pointer_compat(op, arg, 2994 lt, lstp, lst, rn, rtp, rt, rstp, rst)) 2995 return true; 2996 2997 if (check_assign_pointer_integer(op, arg, ltp, lt, rtp, rt)) 2998 return true; 2999 3000 if (check_assign_pointer(op, arg, ltp, lt, rtp, rt)) 3001 return true; 3002 3003 warn_assign(op, arg, ltp, lt, rtp, rt); 3004 return false; 3005 } 3006 3007 static bool 3008 has_side_effect(const tnode_t *tn) /* NOLINT(misc-no-recursion) */ 3009 { 3010 op_t op = tn->tn_op; 3011 3012 if (modtab[op].m_has_side_effect) 3013 return true; 3014 3015 if (op == CVT && tn->tn_type->t_tspec == VOID) 3016 return has_side_effect(tn->u.ops.left); 3017 3018 /* XXX: Why not has_side_effect(tn->u.ops.left) as well? */ 3019 if (op == LOGAND || op == LOGOR) 3020 return has_side_effect(tn->u.ops.right); 3021 3022 /* XXX: Why not has_side_effect(tn->u.ops.left) as well? */ 3023 if (op == QUEST) 3024 return has_side_effect(tn->u.ops.right); 3025 3026 if (op == COLON || op == COMMA) { 3027 return has_side_effect(tn->u.ops.left) || 3028 has_side_effect(tn->u.ops.right); 3029 } 3030 3031 return false; 3032 } 3033 3034 static bool 3035 is_void_cast(const tnode_t *tn) 3036 { 3037 3038 return tn->tn_op == CVT && tn->tn_cast && 3039 tn->tn_type->t_tspec == VOID; 3040 } 3041 3042 static bool 3043 is_local_symbol(const tnode_t *tn) 3044 { 3045 3046 return tn->tn_op == LOAD && 3047 tn->u.ops.left->tn_op == NAME && 3048 tn->u.ops.left->u.sym->s_scl == AUTO; 3049 } 3050 3051 static bool 3052 is_int_constant_zero(const tnode_t *tn) 3053 { 3054 3055 return tn->tn_op == CON && 3056 tn->tn_type->t_tspec == INT && 3057 tn->u.value.u.integer == 0; 3058 } 3059 3060 static void 3061 check_null_effect(const tnode_t *tn) 3062 { 3063 3064 if (hflag && 3065 !has_side_effect(tn) && 3066 !(is_void_cast(tn) && is_local_symbol(tn->u.ops.left)) && 3067 !(is_void_cast(tn) && is_int_constant_zero(tn->u.ops.left))) { 3068 /* expression has null effect */ 3069 warning(129); 3070 } 3071 } 3072 3073 /* 3074 * Check the types for specific operators and type combinations. 3075 * 3076 * At this point, the operands already conform to the type requirements of 3077 * the operator, such as being integer, floating or scalar. 3078 */ 3079 static bool 3080 typeok_op(op_t op, int arg, 3081 const tnode_t *ln, const type_t *ltp, tspec_t lt, 3082 const tnode_t *rn, const type_t *rtp, tspec_t rt) 3083 { 3084 switch (op) { 3085 case ARROW: 3086 return typeok_arrow(lt); 3087 case POINT: 3088 return typeok_point(ln, ltp, lt); 3089 case INCBEF: 3090 case DECBEF: 3091 case INCAFT: 3092 case DECAFT: 3093 return typeok_incdec(op, ln, ltp); 3094 case INDIR: 3095 return typeok_indir(ltp, lt); 3096 case ADDR: 3097 return typeok_address(op, ln, ltp, lt); 3098 case PLUS: 3099 return typeok_plus(op, ltp, lt, rtp, rt); 3100 case MINUS: 3101 return typeok_minus(op, ltp, lt, rtp, rt); 3102 case SHL: 3103 typeok_shl(op, lt, rt); 3104 goto shift; 3105 case SHR: 3106 typeok_shr(op, ln, lt, rn, rt); 3107 shift: 3108 typeok_shift(ltp, lt, rn, rt); 3109 break; 3110 case LT: 3111 case LE: 3112 case GT: 3113 case GE: 3114 compare: 3115 return typeok_compare(op, ln, ltp, lt, rn, rtp, rt); 3116 case EQ: 3117 case NE: 3118 if (is_typeok_eq(ln, lt, rn, rt)) 3119 break; 3120 goto compare; 3121 case QUEST: 3122 return typeok_quest(lt, rn); 3123 case COLON: 3124 return typeok_colon(ln, ltp, lt, rn, rtp, rt); 3125 case ASSIGN: 3126 case INIT: 3127 case FARG: 3128 case RETURN: 3129 if (!check_assign_types_compatible(op, arg, ln, rn)) 3130 return false; 3131 goto assign; 3132 case MULASS: 3133 case DIVASS: 3134 case MODASS: 3135 goto assign; 3136 case ADDASS: 3137 case SUBASS: 3138 if ((lt == PTR && !is_integer(rt)) || rt == PTR) { 3139 warn_incompatible_types(op, ltp, lt, rtp, rt); 3140 return false; 3141 } 3142 goto assign; 3143 case SHLASS: 3144 goto assign; 3145 case SHRASS: 3146 if (pflag && !is_uinteger(lt) && 3147 !(!allow_c90 && is_uinteger(rt))) { 3148 /* bitwise '%s' on signed value possibly nonportable */ 3149 warning(117, op_name(op)); 3150 } 3151 goto assign; 3152 case ANDASS: 3153 case XORASS: 3154 case ORASS: 3155 assign: 3156 return typeok_assign(op, ln, ltp, lt); 3157 case COMMA: 3158 if (!modtab[ln->tn_op].m_has_side_effect) 3159 check_null_effect(ln); 3160 break; 3161 default: 3162 break; 3163 } 3164 return true; 3165 } 3166 3167 static void 3168 check_bad_enum_operation(op_t op, const tnode_t *ln, const tnode_t *rn) 3169 { 3170 3171 if (!eflag) 3172 return; 3173 3174 /* Allow enum in array indices. */ 3175 if (op == PLUS && 3176 ((ln->tn_type->t_is_enum && rn->tn_type->t_tspec == PTR) || 3177 (rn->tn_type->t_is_enum && ln->tn_type->t_tspec == PTR))) { 3178 return; 3179 } 3180 3181 /* dubious operation '%s' on enum */ 3182 warning(241, op_name(op)); 3183 } 3184 3185 static void 3186 check_enum_type_mismatch(op_t op, int arg, const tnode_t *ln, const tnode_t *rn) 3187 { 3188 const mod_t *mp = &modtab[op]; 3189 3190 if (ln->tn_type->u.enumer != rn->tn_type->u.enumer) { 3191 switch (op) { 3192 case INIT: 3193 /* enum type mismatch between '%s' and '%s' in ... */ 3194 warning(210, 3195 type_name(ln->tn_type), type_name(rn->tn_type)); 3196 break; 3197 case FARG: 3198 /* function expects '%s', passing '%s' for arg #%d */ 3199 warning(156, 3200 type_name(ln->tn_type), type_name(rn->tn_type), 3201 arg); 3202 break; 3203 case RETURN: 3204 /* function has return type '%s' but returns '%s' */ 3205 warning(211, 3206 type_name(ln->tn_type), type_name(rn->tn_type)); 3207 break; 3208 default: 3209 /* enum type mismatch: '%s' '%s' '%s' */ 3210 warning(130, type_name(ln->tn_type), op_name(op), 3211 type_name(rn->tn_type)); 3212 break; 3213 } 3214 } else if (Pflag && eflag && mp->m_comparison && op != EQ && op != NE) 3215 /* operator '%s' assumes that '%s' is ordered */ 3216 warning(243, op_name(op), type_name(ln->tn_type)); 3217 } 3218 3219 static void 3220 check_enum_int_mismatch(op_t op, int arg, const tnode_t *ln, const tnode_t *rn) 3221 { 3222 3223 if (!eflag) 3224 return; 3225 3226 switch (op) { 3227 case INIT: 3228 /* 3229 * Initialization with 0 is allowed. Otherwise, all implicit 3230 * initializations would need to be warned upon as well. 3231 */ 3232 if (!rn->tn_type->t_is_enum && rn->tn_op == CON && 3233 is_integer(rn->tn_type->t_tspec) && 3234 rn->u.value.u.integer == 0) { 3235 return; 3236 } 3237 /* initialization of '%s' with '%s' */ 3238 warning(277, type_name(ln->tn_type), type_name(rn->tn_type)); 3239 break; 3240 case FARG: 3241 /* combination of '%s' and '%s', arg #%d */ 3242 warning(278, 3243 type_name(ln->tn_type), type_name(rn->tn_type), arg); 3244 break; 3245 case RETURN: 3246 /* combination of '%s' and '%s' in return */ 3247 warning(279, type_name(ln->tn_type), type_name(rn->tn_type)); 3248 break; 3249 default: 3250 /* combination of '%s' and '%s', op '%s' */ 3251 warning(242, type_name(ln->tn_type), type_name(rn->tn_type), 3252 op_name(op)); 3253 break; 3254 } 3255 } 3256 3257 static void 3258 typeok_enum(op_t op, const mod_t *mp, int arg, 3259 const tnode_t *ln, const type_t *ltp, 3260 const tnode_t *rn, const type_t *rtp) 3261 { 3262 if (mp->m_bad_on_enum && 3263 (ltp->t_is_enum || (mp->m_binary && rtp->t_is_enum))) { 3264 check_bad_enum_operation(op, ln, rn); 3265 } else if (mp->m_valid_on_enum && 3266 (ltp->t_is_enum && rtp != NULL && rtp->t_is_enum)) { 3267 check_enum_type_mismatch(op, arg, ln, rn); 3268 } else if (mp->m_valid_on_enum && 3269 (ltp->t_is_enum || (rtp != NULL && rtp->t_is_enum))) { 3270 check_enum_int_mismatch(op, arg, ln, rn); 3271 } 3272 } 3273 3274 /* Perform most type checks. Return whether the types are ok. */ 3275 bool 3276 typeok(op_t op, int arg, const tnode_t *ln, const tnode_t *rn) 3277 { 3278 3279 const mod_t *mp = &modtab[op]; 3280 3281 type_t *ltp = ln->tn_type; 3282 tspec_t lt = ltp->t_tspec; 3283 3284 type_t *rtp = mp->m_binary ? rn->tn_type : NULL; 3285 tspec_t rt = mp->m_binary ? rtp->t_tspec : NO_TSPEC; 3286 3287 if (Tflag && !typeok_scalar_strict_bool(op, mp, arg, ln, rn)) 3288 return false; 3289 if (!typeok_scalar(op, mp, ltp, lt, rtp, rt)) 3290 return false; 3291 3292 if (!typeok_op(op, arg, ln, ltp, lt, rn, rtp, rt)) 3293 return false; 3294 3295 typeok_enum(op, mp, arg, ln, ltp, rn, rtp); 3296 return true; 3297 } 3298 3299 /* In traditional C, keep unsigned and promote FLOAT to DOUBLE. */ 3300 static tspec_t 3301 promote_trad(tspec_t t) 3302 { 3303 3304 if (t == UCHAR || t == USHORT) 3305 return UINT; 3306 if (t == CHAR || t == SCHAR || t == SHORT) 3307 return INT; 3308 if (t == FLOAT) 3309 return DOUBLE; 3310 if (t == ENUM) 3311 return INT; 3312 return t; 3313 } 3314 3315 /* 3316 * C99 6.3.1.1p2 requires for types with lower rank than int that "If an int 3317 * can represent all the values of the original type, the value is converted 3318 * to an int; otherwise it is converted to an unsigned int", and that "All 3319 * other types are unchanged by the integer promotions". 3320 */ 3321 static tspec_t 3322 promote_c90(const tnode_t *tn, tspec_t t, bool farg) 3323 { 3324 if (tn->tn_type->t_bitfield) { 3325 unsigned int width = tn->tn_type->t_bit_field_width; 3326 unsigned int int_width = size_in_bits(INT); 3327 // XXX: What about _Bool bit-fields, since C99? 3328 if (width < int_width) 3329 return INT; 3330 if (width == int_width) 3331 return is_uinteger(t) ? UINT : INT; 3332 return t; 3333 } 3334 3335 if (t == CHAR || t == SCHAR) 3336 return INT; 3337 if (t == UCHAR) 3338 return size_in_bits(CHAR) < size_in_bits(INT) ? INT : UINT; 3339 if (t == SHORT) 3340 return INT; 3341 if (t == USHORT) 3342 return size_in_bits(SHORT) < size_in_bits(INT) ? INT : UINT; 3343 if (t == ENUM) 3344 return INT; 3345 if (farg && t == FLOAT) 3346 return DOUBLE; 3347 return t; 3348 } 3349 3350 /* 3351 * Performs the "integer promotions" (C99 6.3.1.1p2), which convert small 3352 * integer types to either int or unsigned int. 3353 * 3354 * If allow_c90 is unset or the operand is a function argument with no type 3355 * information (no prototype or variable # of args), converts float to double. 3356 */ 3357 tnode_t * 3358 promote(op_t op, bool farg, tnode_t *tn) 3359 { 3360 3361 const type_t *otp = tn->tn_type; 3362 tspec_t ot = otp->t_tspec; 3363 if (!is_arithmetic(ot)) 3364 return tn; 3365 3366 tspec_t nt = allow_c90 ? promote_c90(tn, ot, farg) : promote_trad(ot); 3367 if (nt == ot) 3368 return tn; 3369 3370 type_t *ntp = expr_dup_type(gettyp(nt)); 3371 ntp->t_tspec = nt; 3372 ntp->t_is_enum = otp->t_is_enum; 3373 if (ntp->t_is_enum) 3374 ntp->u.enumer = otp->u.enumer; 3375 ntp->t_bitfield = otp->t_bitfield; 3376 if (ntp->t_bitfield) { 3377 ntp->t_bit_field_width = otp->t_bit_field_width; 3378 ntp->t_bit_field_offset = otp->t_bit_field_offset; 3379 } 3380 if (ntp->t_bitfield && is_uinteger(ot) && !is_uinteger(nt)) 3381 ntp->t_bit_field_width++; 3382 return convert(op, 0, ntp, tn); 3383 } 3384 3385 static void 3386 check_lossy_floating_to_integer_conversion( 3387 op_t op, int arg, const type_t *tp, const tnode_t *tn) 3388 { 3389 long double x = tn->u.value.u.floating; 3390 integer_constraints ic = ic_any(tp); 3391 if (is_uinteger(tp->t_tspec) 3392 ? x >= ic.umin && x <= ic.umax && x == (uint64_t)x 3393 : x >= ic.smin && x <= ic.smax && x == (int64_t)x) 3394 return; 3395 if (op == FARG) 3396 /* lossy conversion of %Lg to '%s', arg #%d */ 3397 warning(380, x, type_name(tp), arg); 3398 else 3399 /* lossy conversion of %Lg to '%s' */ 3400 warning(381, x, type_name(tp)); 3401 } 3402 3403 static void 3404 convert_integer_from_floating( 3405 op_t op, int arg, const type_t *tp, const tnode_t *tn) 3406 { 3407 3408 if (op == CVT) 3409 /* cast from floating point '%s' to integer '%s' */ 3410 query_message(2, type_name(tn->tn_type), type_name(tp)); 3411 else 3412 /* implicit conversion from floating point '%s' to ... */ 3413 query_message(1, type_name(tn->tn_type), type_name(tp)); 3414 if (tn->tn_op == CON) 3415 check_lossy_floating_to_integer_conversion(op, arg, tp, tn); 3416 } 3417 3418 static bool 3419 should_warn_about_prototype_conversion(tspec_t nt, 3420 tspec_t ot, const tnode_t *ptn) 3421 { 3422 3423 if (nt == ot) 3424 return false; 3425 3426 if (nt == ENUM && ot == INT) 3427 return false; 3428 3429 if (is_floating(nt) != is_floating(ot) || 3430 portable_rank_cmp(nt, ot) != 0) { 3431 /* representation and/or width change */ 3432 if (!is_integer(ot)) 3433 return true; 3434 /* 3435 * XXX: Investigate whether this rule makes sense; see 3436 * tests/usr.bin/xlint/lint1/platform_long.c. 3437 */ 3438 return portable_rank_cmp(ot, INT) > 0; 3439 } 3440 3441 if (!hflag) 3442 return false; 3443 3444 /* 3445 * If the types differ only in sign and the argument has the same 3446 * representation in both types, print no warning. 3447 */ 3448 if (ptn->tn_op == CON && is_integer(nt) && 3449 signed_type(nt) == signed_type(ot) && 3450 !msb(ptn->u.value.u.integer, ot)) 3451 return false; 3452 3453 return true; 3454 } 3455 3456 /* 3457 * Warn if a prototype causes a type conversion that is different from what 3458 * would happen to the same argument in the absence of a prototype. This 3459 * check is intended for code that needs to stay compatible with pre-C90 C. 3460 * 3461 * Errors/warnings about illegal type combinations are already printed 3462 * in check_assign_types_compatible(). 3463 */ 3464 static void 3465 check_prototype_conversion(int arg, tspec_t nt, tspec_t ot, type_t *tp, 3466 tnode_t *tn) 3467 { 3468 3469 if (!is_arithmetic(nt) || !is_arithmetic(ot)) 3470 return; 3471 3472 /* 3473 * If the type of the formal parameter is char/short, a warning would 3474 * be useless, because functions declared the old style can't expect 3475 * char/short arguments. 3476 */ 3477 if (nt == CHAR || nt == SCHAR || nt == UCHAR || 3478 nt == SHORT || nt == USHORT) 3479 return; 3480 3481 tnode_t *ptn = promote(NOOP, true, tn); 3482 ot = ptn->tn_type->t_tspec; 3483 3484 if (should_warn_about_prototype_conversion(nt, ot, ptn)) { 3485 /* argument %d is converted from '%s' to '%s' ... */ 3486 warning(259, arg, type_name(tn->tn_type), type_name(tp)); 3487 } 3488 } 3489 3490 /* 3491 * When converting a large integer type to a small integer type, in some 3492 * cases the value of the actual expression is further restricted than the 3493 * type bounds, such as in (expr & 0xFF) or (expr % 100) or (expr >> 24). 3494 */ 3495 static bool 3496 can_represent(const type_t *tp, const tnode_t *tn) 3497 { 3498 uint64_t nmask = value_bits(width_in_bits(tp)); 3499 if (!is_uinteger(tp->t_tspec)) 3500 nmask >>= 1; 3501 3502 integer_constraints c = ic_expr(tn); 3503 if ((~c.bclr & ~nmask) == 0) 3504 return true; 3505 3506 integer_constraints tpc = ic_any(tp); 3507 if (is_uinteger(tp->t_tspec) 3508 ? tpc.umin <= c.umin && tpc.umax >= c.umax 3509 : tpc.smin <= c.smin && tpc.smax >= c.smax) 3510 return true; 3511 3512 debug_enter(); 3513 debug_step("type '%s' cannot represent:", type_name(tp)); 3514 debug_node(tn); 3515 debug_leave(); 3516 return false; 3517 } 3518 3519 static bool 3520 should_warn_about_integer_conversion(const type_t *ntp, tspec_t nt, 3521 const tnode_t *otn, tspec_t ot) 3522 { 3523 3524 // XXX: The portable_rank_cmp aims at portable mode, independent of the 3525 // current platform, while can_represent acts on the actual type sizes 3526 // from the current platform. This mix is inconsistent, but anything 3527 // else would make the exact conditions too complicated to grasp. 3528 if (aflag > 0 && portable_rank_cmp(nt, ot) < 0) { 3529 if (ot == LONG || ot == ULONG 3530 || ot == LLONG || ot == ULLONG 3531 #ifdef INT128_SIZE 3532 || ot == INT128 || ot == UINT128 3533 #endif 3534 || aflag > 1) 3535 return !can_represent(ntp, otn); 3536 } 3537 return false; 3538 } 3539 3540 static void 3541 convert_integer_from_integer(op_t op, int arg, tspec_t nt, tspec_t ot, 3542 type_t *tp, tnode_t *tn) 3543 { 3544 3545 if (tn->tn_op == CON) 3546 return; 3547 3548 if (op == CVT) 3549 return; 3550 3551 if (Pflag && pflag && aflag > 0 && 3552 portable_rank_cmp(nt, ot) > 0 && 3553 is_uinteger(nt) != is_uinteger(ot)) { 3554 if (op == FARG) 3555 /* conversion to '%s' may sign-extend ... */ 3556 warning(297, type_name(tp), arg); 3557 else 3558 /* conversion to '%s' may sign-extend ... */ 3559 warning(131, type_name(tp)); 3560 } 3561 3562 if (Pflag && portable_rank_cmp(nt, ot) > 0 && 3563 (tn->tn_op == PLUS || tn->tn_op == MINUS || tn->tn_op == MULT || 3564 tn->tn_op == SHL)) { 3565 /* suggest cast from '%s' to '%s' on op '%s' to ... */ 3566 warning(324, type_name(gettyp(ot)), type_name(tp), 3567 op_name(tn->tn_op)); 3568 } 3569 3570 if (should_warn_about_integer_conversion(tp, nt, tn, ot)) { 3571 if (op == FARG) { 3572 /* conversion from '%s' to '%s' may lose ... */ 3573 warning(298, 3574 type_name(tn->tn_type), type_name(tp), arg); 3575 } else { 3576 /* conversion from '%s' to '%s' may lose accuracy */ 3577 warning(132, 3578 type_name(tn->tn_type), type_name(tp)); 3579 } 3580 } 3581 3582 if (is_uinteger(nt) != is_uinteger(ot)) 3583 /* implicit conversion changes sign from '%s' to '%s' */ 3584 query_message(3, type_name(tn->tn_type), type_name(tp)); 3585 } 3586 3587 static void 3588 convert_integer_from_pointer(op_t op, tspec_t nt, type_t *tp, tnode_t *tn) 3589 { 3590 3591 if (tn->tn_op == CON) 3592 return; 3593 if (op != CVT) 3594 return; /* We already got an error. */ 3595 if (portable_rank_cmp(nt, PTR) >= 0) 3596 return; 3597 3598 if (pflag && size_in_bits(nt) >= size_in_bits(PTR)) { 3599 /* conversion of pointer to '%s' may lose bits */ 3600 warning(134, type_name(tp)); 3601 } else { 3602 /* conversion of pointer to '%s' loses bits */ 3603 warning(133, type_name(tp)); 3604 } 3605 } 3606 3607 static bool 3608 struct_starts_with(const type_t *struct_tp, const type_t *member_tp) 3609 { 3610 3611 return struct_tp->u.sou->sou_first_member != NULL && 3612 types_compatible(struct_tp->u.sou->sou_first_member->s_type, 3613 member_tp, true, false, NULL); 3614 } 3615 3616 static bool 3617 is_byte_array(const type_t *tp) 3618 { 3619 3620 return tp->t_tspec == ARRAY && 3621 (tp->t_subt->t_tspec == CHAR || tp->t_subt->t_tspec == UCHAR); 3622 } 3623 3624 static bool 3625 union_contains(const type_t *utp, const type_t *mtp) 3626 { 3627 for (const sym_t *mem = utp->u.sou->sou_first_member; 3628 mem != NULL; mem = mem->s_next) { 3629 if (types_compatible(mem->s_type, mtp, true, false, NULL)) 3630 return true; 3631 } 3632 return false; 3633 } 3634 3635 static bool 3636 should_warn_about_pointer_cast(const type_t *nstp, tspec_t nst, 3637 const type_t *ostp, tspec_t ost) 3638 { 3639 3640 while (nst == ARRAY) 3641 nstp = nstp->t_subt, nst = nstp->t_tspec; 3642 while (ost == ARRAY) 3643 ostp = ostp->t_subt, ost = ostp->t_tspec; 3644 3645 if (nst == STRUCT && ost == STRUCT && 3646 (struct_starts_with(nstp, ostp) || 3647 struct_starts_with(ostp, nstp))) 3648 return false; 3649 3650 if (is_incomplete(nstp) || is_incomplete(ostp)) 3651 return false; 3652 3653 if (nst == CHAR || nst == UCHAR) 3654 return false; /* for the sake of traditional C code */ 3655 if (ost == CHAR || ost == UCHAR) 3656 return false; /* for the sake of traditional C code */ 3657 3658 /* Allow cast between pointers to sockaddr variants. */ 3659 if (nst == STRUCT && ost == STRUCT) { 3660 const sym_t *nmem = nstp->u.sou->sou_first_member; 3661 const sym_t *omem = ostp->u.sou->sou_first_member; 3662 while (nmem != NULL && omem != NULL && 3663 types_compatible(nmem->s_type, omem->s_type, 3664 true, false, NULL)) 3665 nmem = nmem->s_next, omem = omem->s_next; 3666 if (nmem != NULL && is_byte_array(nmem->s_type)) 3667 return false; 3668 if (omem != NULL && is_byte_array(omem->s_type)) 3669 return false; 3670 if (nmem == NULL && omem == NULL) 3671 return false; 3672 } 3673 3674 if (nst == UNION || ost == UNION) { 3675 const type_t *union_tp = nst == UNION ? nstp : ostp; 3676 const type_t *other_tp = nst == UNION ? ostp : nstp; 3677 if (union_contains(union_tp, other_tp)) 3678 return false; 3679 } 3680 3681 if (is_struct_or_union(nst) && is_struct_or_union(ost)) 3682 return nstp->u.sou != ostp->u.sou; 3683 3684 enum rank_kind rk1 = type_properties(nst)->tt_rank_kind; 3685 enum rank_kind rk2 = type_properties(ost)->tt_rank_kind; 3686 if (rk1 != rk2 || rk1 == RK_NONE) 3687 return true; 3688 3689 return portable_rank_cmp(nst, ost) != 0; 3690 } 3691 3692 static void 3693 convert_pointer_from_pointer(type_t *ntp, tnode_t *tn) 3694 { 3695 const type_t *nstp = ntp->t_subt; 3696 const type_t *otp = tn->tn_type; 3697 const type_t *ostp = otp->t_subt; 3698 tspec_t nst = nstp->t_tspec; 3699 tspec_t ost = ostp->t_tspec; 3700 3701 if (nst == VOID || ost == VOID) { 3702 /* TODO: C99 behaves like C90 here. */ 3703 if (!allow_trad && !allow_c99 && (nst == FUNC || ost == FUNC)) { 3704 const char *nts, *ots; 3705 /* null pointers are already handled in convert() */ 3706 *(nst == FUNC ? &nts : &ots) = "function pointer"; 3707 *(nst == VOID ? &nts : &ots) = "'void *'"; 3708 /* conversion of %s to %s requires a cast */ 3709 warning(303, ots, nts); 3710 } 3711 return; 3712 } 3713 if (nst == FUNC && ost == FUNC) 3714 return; 3715 if (nst == FUNC || ost == FUNC) { 3716 /* converting '%s' to '%s' is questionable */ 3717 warning(229, type_name(otp), type_name(ntp)); 3718 return; 3719 } 3720 3721 if (hflag && alignment(nstp) > alignment(ostp) && 3722 ost != CHAR && ost != UCHAR && 3723 !is_incomplete(ostp) && 3724 !(nst == UNION && union_contains(nstp, ostp))) { 3725 /* converting '%s' to '%s' increases alignment ... */ 3726 warning(135, type_name(otp), type_name(ntp), 3727 alignment(ostp), alignment(nstp)); 3728 } 3729 3730 if (cflag && should_warn_about_pointer_cast(nstp, nst, ostp, ost)) { 3731 /* pointer cast from '%s' to unrelated '%s' */ 3732 warning(247, type_name(ostp), type_name(nstp)); 3733 } 3734 } 3735 3736 /* 3737 * Insert a conversion operator, which converts the type of the node 3738 * to another given type. 3739 * 3740 * Possible values for 'op': 3741 * CVT a cast-expression 3742 * binary integer promotion for one of the operands, or a usual 3743 * arithmetic conversion 3744 * binary plain or compound assignments to bit-fields 3745 * FARG 'arg' is the number of the parameter (used for warnings) 3746 * NOOP several other implicit conversions 3747 * ... 3748 */ 3749 tnode_t * 3750 convert(op_t op, int arg, type_t *tp, tnode_t *tn) 3751 { 3752 tspec_t nt = tp->t_tspec; 3753 tspec_t ot = tn->tn_type->t_tspec; 3754 3755 if (allow_trad && allow_c90 && op == FARG) 3756 check_prototype_conversion(arg, nt, ot, tp, tn); 3757 3758 if (nt == BOOL) { 3759 /* No further checks. */ 3760 3761 } else if (is_integer(nt)) { 3762 if (ot == BOOL) { 3763 /* No further checks. */ 3764 } else if (is_integer(ot)) 3765 convert_integer_from_integer(op, arg, nt, ot, tp, tn); 3766 else if (is_floating(ot)) 3767 convert_integer_from_floating(op, arg, tp, tn); 3768 else if (ot == PTR) 3769 convert_integer_from_pointer(op, nt, tp, tn); 3770 3771 } else if (is_floating(nt)) { 3772 if (is_integer(ot) && op != CVT) { 3773 /* implicit conversion from integer '%s' to ... */ 3774 query_message(19, 3775 type_name(tn->tn_type), type_name(tp)); 3776 } 3777 3778 } else if (nt == PTR) { 3779 if (is_null_pointer(tn)) { 3780 /* a null pointer may be assigned to any pointer. */ 3781 } else if (ot == PTR && op == CVT) 3782 convert_pointer_from_pointer(tp, tn); 3783 } 3784 3785 tnode_t *ntn = expr_alloc_tnode(); 3786 ntn->tn_op = CVT; 3787 ntn->tn_type = tp; 3788 ntn->tn_cast = op == CVT; 3789 ntn->tn_sys |= tn->tn_sys; 3790 ntn->u.ops.right = NULL; 3791 if (tn->tn_op != CON || nt == VOID) { 3792 ntn->u.ops.left = tn; 3793 } else { 3794 ntn->tn_op = CON; 3795 convert_constant(op, arg, ntn->tn_type, &ntn->u.value, 3796 &tn->u.value); 3797 } 3798 3799 return ntn; 3800 } 3801 3802 static void 3803 convert_constant_from_floating(op_t op, int arg, const type_t *ntp, 3804 tspec_t nt, val_t *nv, val_t *ov) 3805 { 3806 long double max = 0.0, min = 0.0; 3807 3808 switch (nt) { 3809 case CHAR: 3810 max = TARG_CHAR_MAX; min = TARG_CHAR_MIN; break; 3811 case UCHAR: 3812 max = TARG_UCHAR_MAX; min = 0; break; 3813 case SCHAR: 3814 max = TARG_SCHAR_MAX; min = TARG_SCHAR_MIN; break; 3815 case SHORT: 3816 max = TARG_SHRT_MAX; min = TARG_SHRT_MIN; break; 3817 case USHORT: 3818 max = TARG_USHRT_MAX; min = 0; break; 3819 case ENUM: 3820 case INT: 3821 max = TARG_INT_MAX; min = TARG_INT_MIN; break; 3822 case UINT: 3823 max = TARG_UINT_MAX; min = 0; break; 3824 case LONG: 3825 max = TARG_LONG_MAX; min = TARG_LONG_MIN; break; 3826 case ULONG: 3827 max = TARG_ULONG_MAX; min = 0; break; 3828 case LLONG: 3829 max = LLONG_MAX; min = LLONG_MIN; break; 3830 case ULLONG: 3831 max = ULLONG_MAX; min = 0; break; 3832 case FLOAT: 3833 case FCOMPLEX: 3834 max = FLT_MAX; min = -FLT_MAX; break; 3835 case DOUBLE: 3836 case DCOMPLEX: 3837 max = DBL_MAX; min = -DBL_MAX; break; 3838 case LDOUBLE: 3839 case LCOMPLEX: 3840 /* LINTED 248; see floating_error_value. */ 3841 max = LDBL_MAX; min = -max; break; 3842 default: 3843 lint_assert(/*CONSTCOND*/false); 3844 } 3845 if (ov->u.floating > max || ov->u.floating < min) { 3846 lint_assert(nt != LDOUBLE); 3847 const char *ot_name = type_name(gettyp(ov->v_tspec)); 3848 const char *nt_name = type_name(ntp); 3849 if (is_integer(nt)) 3850 goto after_warning; 3851 if (op == FARG) 3852 /* conversion of '%s' to '%s' is out of range, ... */ 3853 warning(295, ot_name, nt_name, arg); 3854 else 3855 /* conversion of '%s' to '%s' is out of range */ 3856 warning(119, ot_name, nt_name); 3857 after_warning: 3858 ov->u.floating = ov->u.floating > 0 ? max : min; 3859 } 3860 3861 if (nt == FLOAT || nt == FCOMPLEX) 3862 nv->u.floating = (float)ov->u.floating; 3863 else if (nt == DOUBLE || nt == DCOMPLEX) 3864 nv->u.floating = (double)ov->u.floating; 3865 else if (nt == LDOUBLE || nt == LCOMPLEX) 3866 nv->u.floating = ov->u.floating; 3867 else 3868 nv->u.integer = (int64_t)ov->u.floating; 3869 } 3870 3871 static bool 3872 convert_constant_to_floating(tspec_t nt, val_t *nv, 3873 tspec_t ot, const val_t *v) 3874 { 3875 if (nt == FLOAT) { 3876 nv->u.floating = (ot == PTR || is_uinteger(ot)) ? 3877 (float)(uint64_t)v->u.integer : (float)v->u.integer; 3878 } else if (nt == DOUBLE) { 3879 nv->u.floating = (ot == PTR || is_uinteger(ot)) ? 3880 (double)(uint64_t)v->u.integer : (double)v->u.integer; 3881 } else if (nt == LDOUBLE) { 3882 nv->u.floating = (ot == PTR || is_uinteger(ot)) 3883 ? (long double)(uint64_t)v->u.integer 3884 : (long double)v->u.integer; 3885 } else 3886 return false; 3887 return true; 3888 } 3889 3890 /* 3891 * Print a warning if bits which were set are lost due to the conversion. 3892 * This can happen with operator ORASS only. 3893 */ 3894 static void 3895 convert_constant_check_range_bitor(size_t nsz, size_t osz, const val_t *v, 3896 uint64_t xmask, op_t op) 3897 { 3898 if (nsz < osz && (v->u.integer & xmask) != 0) 3899 /* constant truncated by conversion, op '%s' */ 3900 warning(306, op_name(op)); 3901 } 3902 3903 static void 3904 convert_constant_check_range_bitand(size_t nsz, size_t osz, 3905 uint64_t xmask, const val_t *nv, 3906 tspec_t ot, const val_t *v, 3907 const type_t *tp, op_t op) 3908 { 3909 if (nsz > osz && 3910 (nv->u.integer & bit((unsigned int)(osz - 1))) != 0 && 3911 (nv->u.integer & xmask) != xmask) { 3912 /* extra bits set to 0 in conversion of '%s' to '%s', ... */ 3913 warning(309, type_name(gettyp(ot)), 3914 type_name(tp), op_name(op)); 3915 } else if (nsz < osz && 3916 (v->u.integer & xmask) != xmask && 3917 (v->u.integer & xmask) != 0) 3918 /* constant truncated by conversion, op '%s' */ 3919 warning(306, op_name(op)); 3920 } 3921 3922 static void 3923 convert_constant_check_range_signed(op_t op, int arg, 3924 const type_t *ntp, int64_t ov) 3925 { 3926 if (op == ASSIGN) 3927 /* assignment of negative constant %lld to unsigned ... */ 3928 warning(164, (long long)ov, type_name(ntp)); 3929 else if (op == INIT) 3930 /* initialization of unsigned type '%s' with negative ... */ 3931 warning(221, type_name(ntp), (long long)ov); 3932 else if (op == FARG) 3933 /* conversion of negative constant %lld to unsigned ... */ 3934 warning(296, (long long)ov, type_name(ntp), arg); 3935 else if (modtab[op].m_comparison) { 3936 /* handled by check_integer_comparison() */ 3937 } else 3938 /* conversion of negative constant %lld to unsigned ... */ 3939 warning(222, (long long)ov, type_name(ntp)); 3940 } 3941 3942 /* 3943 * Loss of significant bit(s). All truncated bits of unsigned types or all 3944 * truncated bits plus the msb of the target for signed types are considered 3945 * to be significant bits. Loss of significant bits means that at least one 3946 * of the bits was set in an unsigned type or that at least one but not all 3947 * of the bits was set in a signed type. Loss of significant bits means that 3948 * it is not possible, also not with necessary casts, to convert back to the 3949 * original type. An example for a necessary cast is: 3950 * char c; int i; c = 128; 3951 * i = c; ** yields -128 ** 3952 * i = (unsigned char)c; ** yields 128 ** 3953 */ 3954 static void 3955 warn_constant_check_range_truncated(op_t op, int arg, const type_t *tp, 3956 tspec_t ot) 3957 { 3958 if (op == ASSIGN && tp->t_bitfield) 3959 /* precision lost in bit-field assignment */ 3960 warning(166); 3961 else if (op == ASSIGN) 3962 /* constant truncated by assignment */ 3963 warning(165); 3964 else if (op == INIT && tp->t_bitfield) 3965 /* bit-field initializer does not fit */ 3966 warning(180); 3967 else if (op == INIT) 3968 /* initializer does not fit */ 3969 warning(178); 3970 else if (op == CASE) 3971 /* case label affected by conversion */ 3972 warning(196); 3973 else if (op == FARG) 3974 /* conversion of '%s' to '%s' is out of range, arg #%d */ 3975 warning(295, type_name(gettyp(ot)), type_name(tp), arg); 3976 else 3977 /* conversion of '%s' to '%s' is out of range */ 3978 warning(119, type_name(gettyp(ot)), type_name(tp)); 3979 } 3980 3981 static void 3982 warn_constant_check_range_loss(op_t op, int arg, const type_t *tp, 3983 tspec_t ot) 3984 { 3985 if (op == ASSIGN && tp->t_bitfield) 3986 /* precision lost in bit-field assignment */ 3987 warning(166); 3988 else if (op == INIT && tp->t_bitfield) 3989 /* bit-field initializer out of range */ 3990 warning(11); 3991 else if (op == CASE) 3992 /* case label affected by conversion */ 3993 warning(196); 3994 else if (op == FARG) 3995 /* conversion of '%s' to '%s' is out of range, arg #%d */ 3996 warning(295, type_name(gettyp(ot)), type_name(tp), arg); 3997 else 3998 /* conversion of '%s' to '%s' is out of range */ 3999 warning(119, type_name(gettyp(ot)), type_name(tp)); 4000 } 4001 4002 static void 4003 convert_constant_check_range(tspec_t ot, const type_t *tp, tspec_t nt, 4004 op_t op, int arg, const val_t *v, val_t *nv) 4005 { 4006 unsigned int obitsz, nbitsz; 4007 uint64_t xmask, xmsk1; 4008 4009 obitsz = size_in_bits(ot); 4010 nbitsz = tp->t_bitfield ? tp->t_bit_field_width : size_in_bits(nt); 4011 xmask = value_bits(nbitsz) ^ value_bits(obitsz); 4012 xmsk1 = value_bits(nbitsz) ^ value_bits(obitsz - 1); 4013 if (op == ORASS || op == BITOR || op == BITXOR) { 4014 convert_constant_check_range_bitor( 4015 nbitsz, obitsz, v, xmask, op); 4016 } else if (op == ANDASS || op == BITAND) { 4017 convert_constant_check_range_bitand( 4018 nbitsz, obitsz, xmask, nv, ot, v, tp, op); 4019 } else if (nt != PTR && is_uinteger(nt) && 4020 ot != PTR && !is_uinteger(ot) && 4021 v->u.integer < 0) 4022 convert_constant_check_range_signed(op, arg, 4023 tp, v->u.integer); 4024 else if (nv->u.integer != v->u.integer && nbitsz <= obitsz && 4025 (v->u.integer & xmask) != 0 && 4026 (is_uinteger(ot) || (v->u.integer & xmsk1) != xmsk1)) 4027 warn_constant_check_range_truncated(op, arg, tp, ot); 4028 else if (nv->u.integer != v->u.integer) 4029 warn_constant_check_range_loss(op, arg, tp, ot); 4030 } 4031 4032 /* Converts a typed constant to a constant of another type. */ 4033 void 4034 convert_constant(op_t op, int arg, const type_t *ntp, val_t *nv, val_t *ov) 4035 { 4036 /* 4037 * TODO: make 'ov' const; the name of this function does not suggest 4038 * that it modifies 'ov'. 4039 */ 4040 tspec_t ot = ov->v_tspec; 4041 tspec_t nt = nv->v_tspec = ntp->t_tspec; 4042 bool range_check = false; 4043 4044 if (nt == BOOL) { /* C99 6.3.1.2 */ 4045 nv->v_unsigned_since_c90 = false; 4046 nv->u.integer = is_nonzero_val(ov) ? 1 : 0; 4047 return; 4048 } 4049 4050 if (ot == FLOAT || ot == DOUBLE || ot == LDOUBLE) 4051 convert_constant_from_floating(op, arg, ntp, nt, nv, ov); 4052 else if (!convert_constant_to_floating(nt, nv, ot, ov)) { 4053 range_check = true; /* Check for lost precision. */ 4054 nv->u.integer = ov->u.integer; 4055 } 4056 4057 if (allow_trad && allow_c90 && ov->v_unsigned_since_c90 && 4058 (is_floating(nt) || ( 4059 (is_integer(nt) && !is_uinteger(nt) && 4060 portable_rank_cmp(nt, ot) > 0)))) { 4061 /* C90 treats constant as unsigned */ 4062 warning(157); 4063 ov->v_unsigned_since_c90 = false; 4064 } 4065 4066 if (is_integer(nt)) { 4067 unsigned int size = ntp->t_bitfield 4068 ? ntp->t_bit_field_width : size_in_bits(nt); 4069 nv->u.integer = convert_integer(nv->u.integer, nt, size); 4070 } 4071 4072 if (range_check && op != CVT) 4073 convert_constant_check_range(ot, ntp, nt, op, arg, ov, nv); 4074 } 4075 4076 tnode_t * 4077 build_sizeof(const type_t *tp) 4078 { 4079 unsigned int size_in_bytes = type_size_in_bits(tp) / CHAR_SIZE; 4080 tnode_t *tn = build_integer_constant(SIZEOF_TSPEC, size_in_bytes); 4081 tn->tn_system_dependent = true; 4082 debug_step("build_sizeof '%s' = %u", type_name(tp), size_in_bytes); 4083 return tn; 4084 } 4085 4086 tnode_t * 4087 build_offsetof(const type_t *tp, designation dn) 4088 { 4089 unsigned int offset_in_bits = 0; 4090 4091 if (!is_struct_or_union(tp->t_tspec)) { 4092 /* unacceptable operand of '%s' */ 4093 error(111, "offsetof"); 4094 goto proceed; 4095 } 4096 for (size_t i = 0; i < dn.dn_len; i++) { 4097 const designator *dr = dn.dn_items + i; 4098 if (dr->dr_kind == DK_SUBSCRIPT) { 4099 if (tp->t_tspec != ARRAY) 4100 goto proceed; /* silent error */ 4101 tp = tp->t_subt; 4102 offset_in_bits += (unsigned) dr->dr_subscript 4103 * type_size_in_bits(tp); 4104 } else { 4105 if (!is_struct_or_union(tp->t_tspec)) 4106 goto proceed; /* silent error */ 4107 const char *name = dr->dr_member->s_name; 4108 sym_t *mem = find_member(tp->u.sou, name); 4109 if (mem == NULL) { 4110 /* type '%s' does not have member '%s' */ 4111 error(101, name, type_name(tp)); 4112 goto proceed; 4113 } 4114 tp = mem->s_type; 4115 offset_in_bits += mem->u.s_member.sm_offset_in_bits; 4116 } 4117 } 4118 free(dn.dn_items); 4119 4120 proceed:; 4121 unsigned int offset_in_bytes = offset_in_bits / CHAR_SIZE; 4122 tnode_t *tn = build_integer_constant(SIZEOF_TSPEC, offset_in_bytes); 4123 tn->tn_system_dependent = true; 4124 return tn; 4125 } 4126 4127 unsigned int 4128 type_size_in_bits(const type_t *tp) 4129 { 4130 4131 unsigned int elem = 1; 4132 bool flex = false; 4133 lint_assert(tp != NULL); 4134 while (tp->t_tspec == ARRAY) { 4135 flex = true; /* allow c99 flex arrays [] [0] */ 4136 elem *= tp->u.dimension; 4137 tp = tp->t_subt; 4138 } 4139 if (elem == 0 && !flex) { 4140 /* cannot take size/alignment of incomplete type */ 4141 error(143); 4142 elem = 1; 4143 } 4144 4145 unsigned int elsz; 4146 switch (tp->t_tspec) { 4147 case VOID: 4148 /* cannot take size/alignment of void */ 4149 error(146); 4150 elsz = 1; 4151 break; 4152 case FUNC: 4153 /* cannot take size/alignment of function type '%s' */ 4154 error(144, type_name(tp)); 4155 elsz = 1; 4156 break; 4157 case STRUCT: 4158 case UNION: 4159 if (is_incomplete(tp)) { 4160 /* cannot take size/alignment of incomplete type */ 4161 error(143); 4162 elsz = 1; 4163 } else 4164 elsz = tp->u.sou->sou_size_in_bits; 4165 break; 4166 case ENUM: 4167 if (is_incomplete(tp)) { 4168 /* cannot take size/alignment of incomplete type */ 4169 warning(143); 4170 } 4171 /* FALLTHROUGH */ 4172 default: 4173 if (tp->t_bitfield) 4174 /* cannot take size/alignment of bit-field */ 4175 error(145); 4176 elsz = size_in_bits(tp->t_tspec); 4177 lint_assert(elsz > 0); 4178 break; 4179 } 4180 4181 return elem * elsz; 4182 } 4183 4184 /* C11 6.5.3.4, GCC */ 4185 tnode_t * 4186 build_alignof(const type_t *tp) 4187 { 4188 if (tp->t_tspec == FUNC) { 4189 /* cannot take size/alignment of function type '%s' */ 4190 error(144, type_name(tp)); 4191 return NULL; 4192 } 4193 if (tp->t_tspec == VOID) { 4194 /* cannot take size/alignment of void */ 4195 error(146); 4196 return NULL; 4197 } 4198 if (is_incomplete(tp)) { 4199 /* cannot take size/alignment of incomplete type */ 4200 error(143); 4201 return NULL; 4202 } 4203 if (tp->t_bitfield) { 4204 /* cannot take size/alignment of bit-field */ 4205 error(145); 4206 return NULL; 4207 } 4208 return build_integer_constant(SIZEOF_TSPEC, (int64_t)alignment(tp)); 4209 } 4210 4211 static tnode_t * 4212 cast_to_union(tnode_t *otn, bool sys, type_t *ntp) 4213 { 4214 4215 if (!allow_gcc) { 4216 /* union cast is a GCC extension */ 4217 error(328); 4218 return NULL; 4219 } 4220 4221 for (const sym_t *m = ntp->u.sou->sou_first_member; 4222 m != NULL; m = m->s_next) { 4223 if (types_compatible(m->s_type, otn->tn_type, 4224 false, false, NULL)) { 4225 tnode_t *ntn = build_op(CVT, sys, ntp, otn, NULL); 4226 ntn->tn_cast = true; 4227 return ntn; 4228 } 4229 } 4230 4231 /* type '%s' is not a member of '%s' */ 4232 error(329, type_name(otn->tn_type), type_name(ntp)); 4233 return NULL; 4234 } 4235 4236 // In GCC mode, allow 'nullptr + offset' as a constant expression. 4237 static tnode_t * 4238 null_pointer_offset(tnode_t *tn) 4239 { 4240 uint64_t off = 0; 4241 const tnode_t *n = tn; 4242 while ((n->tn_op == PLUS || n->tn_op == MINUS) 4243 && is_integer(n->u.ops.right->tn_type->t_tspec)) { 4244 off += (uint64_t)n->u.ops.right->u.value.u.integer; 4245 n = n->u.ops.left; 4246 } 4247 if (n->tn_type->t_tspec == PTR 4248 && n->tn_op == ADDR 4249 && n->u.ops.left->tn_op == INDIR 4250 && n->u.ops.left->u.ops.left->tn_op == CON 4251 && n->u.ops.left->u.ops.left->tn_type->t_tspec == PTR) { 4252 off += (uint64_t)n->u.ops.left->u.ops.left->u.value.u.integer; 4253 return build_integer_constant(SIZEOF_TSPEC, (int64_t)off); 4254 } 4255 return tn; 4256 } 4257 4258 tnode_t * 4259 cast(tnode_t *tn, bool sys, type_t *tp) 4260 { 4261 4262 if (tn == NULL) 4263 return NULL; 4264 4265 tn = cconv(tn); 4266 4267 lint_assert(tp != NULL); 4268 tspec_t nt = tp->t_tspec; 4269 tspec_t ot = tn->tn_type->t_tspec; 4270 4271 if (nt == VOID) { 4272 /* 4273 * C90 6.3.4, C99 6.5.4p2 and C11 6.5.4p2 allow any type to be 4274 * cast to void. The only other allowed casts are from a 4275 * scalar type to a scalar type. 4276 */ 4277 } else if (nt == UNION) 4278 return cast_to_union(tn, sys, tp); 4279 else if (nt == STRUCT || nt == ARRAY || nt == FUNC) { 4280 /* Casting to a struct is an undocumented GCC extension. */ 4281 if (!(allow_gcc && nt == STRUCT)) 4282 goto invalid_cast; 4283 } else if (is_struct_or_union(ot)) 4284 goto invalid_cast; 4285 else if (ot == VOID) { 4286 /* improper cast of void expression */ 4287 error(148); 4288 return NULL; 4289 } else if (is_integer(nt) && is_scalar(ot)) { 4290 tn = null_pointer_offset(tn); 4291 } else if (is_floating(nt) && is_arithmetic(ot)) { 4292 /* ok */ 4293 } else if (nt == PTR && is_integer(ot)) { 4294 /* ok */ 4295 } else if (nt == PTR && ot == PTR) { 4296 if (!tp->t_subt->t_const && tn->tn_type->t_subt->t_const) { 4297 if (hflag) 4298 /* cast discards 'const' from type '%s' */ 4299 warning(275, type_name(tn->tn_type)); 4300 } 4301 } else 4302 goto invalid_cast; 4303 4304 if (types_compatible(tp, tn->tn_type, false, false, NULL)) 4305 /* no-op cast from '%s' to '%s' */ 4306 query_message(6, type_name(tn->tn_type), type_name(tp)); 4307 4308 tn = convert(CVT, 0, tp, tn); 4309 tn->tn_cast = true; 4310 tn->tn_sys = sys; 4311 4312 return tn; 4313 4314 invalid_cast: 4315 /* invalid cast from '%s' to '%s' */ 4316 error(147, type_name(tn->tn_type), type_name(tp)); 4317 return NULL; 4318 } 4319 4320 void 4321 add_function_argument(function_call *call, tnode_t *arg) 4322 { 4323 /* 4324 * If there was a serious error in the expression for the argument, 4325 * create a dummy argument so the positions of the remaining arguments 4326 * will not change. 4327 */ 4328 if (arg == NULL) 4329 arg = build_integer_constant(INT, 0); 4330 4331 if (call->args_len >= call->args_cap) { 4332 call->args_cap += 8; 4333 tnode_t **new_args = expr_zero_alloc( 4334 call->args_cap * sizeof(*call->args), "tnode*[]"); 4335 if (call->args_len > 0) 4336 memcpy(new_args, call->args, 4337 call->args_len * sizeof(*call->args)); 4338 call->args = new_args; 4339 } 4340 call->args[call->args_len++] = arg; 4341 } 4342 4343 /* 4344 * Compare the type of an argument with the corresponding type of a 4345 * prototype parameter. If it is a valid combination, but both types 4346 * are not the same, insert a conversion to convert the argument into 4347 * the type of the parameter. 4348 */ 4349 static tnode_t * 4350 check_prototype_argument( 4351 int n, /* pos of arg */ 4352 type_t *tp, /* expected type (from prototype) */ 4353 tnode_t *tn) /* argument */ 4354 { 4355 tnode_t *ln = xcalloc(1, sizeof(*ln)); 4356 ln->tn_type = expr_unqualified_type(tp); 4357 ln->tn_lvalue = true; 4358 if (typeok(FARG, n, ln, tn)) { 4359 bool dowarn; 4360 if (!types_compatible(tp, tn->tn_type, 4361 true, false, (dowarn = false, &dowarn)) || dowarn) 4362 tn = convert(FARG, n, tp, tn); 4363 } 4364 free(ln); 4365 return tn; 4366 } 4367 4368 /* 4369 * Check types of all function arguments and insert conversions, 4370 * if necessary. 4371 */ 4372 static void 4373 check_function_arguments(const function_call *call) 4374 { 4375 type_t *ftp = call->func->tn_type->t_subt; 4376 4377 /* get # of parameters in the prototype */ 4378 int npar = 0; 4379 for (const sym_t *p = ftp->u.params; p != NULL; p = p->s_next) 4380 npar++; 4381 4382 int narg = (int)call->args_len; 4383 4384 const sym_t *param = ftp->u.params; 4385 if (ftp->t_proto && npar != narg && !(ftp->t_vararg && npar < narg)) { 4386 /* argument mismatch: %d %s passed, %d expected */ 4387 error(150, narg, narg != 1 ? "arguments" : "argument", npar); 4388 param = NULL; 4389 } 4390 4391 for (int i = 0; i < narg; i++) { 4392 tnode_t *arg = call->args[i]; 4393 4394 /* some things which are always not allowed */ 4395 tspec_t at = arg->tn_type->t_tspec; 4396 if (at == VOID) { 4397 /* void expressions may not be arguments, arg #%d */ 4398 error(151, i + 1); 4399 return; 4400 } 4401 if (is_struct_or_union(at) && is_incomplete(arg->tn_type)) { 4402 /* argument cannot have unknown size, arg #%d */ 4403 error(152, i + 1); 4404 return; 4405 } 4406 if (is_integer(at) && 4407 arg->tn_type->t_is_enum && 4408 is_incomplete(arg->tn_type)) { 4409 /* argument cannot have unknown size, arg #%d */ 4410 warning(152, i + 1); 4411 } 4412 4413 arg = cconv(arg); 4414 call->args[i] = arg; 4415 4416 arg = param != NULL 4417 ? check_prototype_argument(i + 1, param->s_type, arg) 4418 : promote(NOOP, true, arg); 4419 call->args[i] = arg; 4420 4421 if (param != NULL) 4422 param = param->s_next; 4423 } 4424 } 4425 4426 tnode_t * 4427 build_function_call(tnode_t *func, bool sys, function_call *call) 4428 { 4429 4430 if (func == NULL) 4431 return NULL; 4432 4433 call->func = func; 4434 check_ctype_function_call(call); 4435 4436 func = cconv(func); 4437 call->func = func; 4438 4439 if (func->tn_type->t_tspec != PTR || 4440 func->tn_type->t_subt->t_tspec != FUNC) { 4441 /* cannot call '%s', must be a function */ 4442 error(149, type_name(func->tn_type)); 4443 return NULL; 4444 } 4445 4446 check_function_arguments(call); 4447 4448 tnode_t *ntn = expr_alloc_tnode(); 4449 ntn->tn_op = CALL; 4450 ntn->tn_type = func->tn_type->t_subt->t_subt; 4451 ntn->tn_sys = sys; 4452 ntn->u.call = call; 4453 return ntn; 4454 } 4455 4456 /* 4457 * Return the value of an integral constant expression. 4458 * If the expression is not constant or its type is not an integer 4459 * type, an error message is printed. 4460 */ 4461 val_t * 4462 integer_constant(tnode_t *tn, bool required) 4463 { 4464 4465 if (tn != NULL) 4466 tn = cconv(tn); 4467 if (tn != NULL) 4468 tn = promote(NOOP, false, tn); 4469 4470 val_t *v = xcalloc(1, sizeof(*v)); 4471 4472 if (tn == NULL) { 4473 lint_assert(seen_error); 4474 debug_step("constant node is null; returning 1 instead"); 4475 v->v_tspec = INT; 4476 v->u.integer = 1; 4477 return v; 4478 } 4479 4480 v->v_tspec = tn->tn_type->t_tspec; 4481 4482 if (tn->tn_op == CON) { 4483 lint_assert(tn->tn_type->t_tspec == tn->u.value.v_tspec); 4484 if (is_integer(tn->u.value.v_tspec)) { 4485 v->v_unsigned_since_c90 = 4486 tn->u.value.v_unsigned_since_c90; 4487 v->u.integer = tn->u.value.u.integer; 4488 return v; 4489 } 4490 v->u.integer = (int64_t)tn->u.value.u.floating; 4491 } else 4492 v->u.integer = 1; 4493 4494 if (required) 4495 /* integral constant expression expected */ 4496 error(55); 4497 else 4498 /* variable array dimension is a C99/GCC extension */ 4499 c99ism(318); 4500 4501 if (!is_integer(v->v_tspec)) 4502 v->v_tspec = INT; 4503 4504 return v; 4505 } 4506 4507 static bool 4508 is_constcond_false(const tnode_t *tn, tspec_t t) 4509 { 4510 return (t == BOOL || t == INT) && 4511 tn->tn_op == CON && tn->u.value.u.integer == 0; 4512 } 4513 4514 /* 4515 * Perform some tests on expressions which can't be done in build_binary() 4516 * and functions called by build_binary(). These tests must be done here 4517 * because we need some information about the context in which the operations 4518 * are performed. 4519 * After all tests are performed and dofreeblk is true, expr() frees the 4520 * memory which is used for the expression. 4521 */ 4522 void 4523 expr(tnode_t *tn, bool vctx, bool cond, bool dofreeblk, bool is_do_while, 4524 const char *stmt_kind) 4525 { 4526 4527 if (tn == NULL) { /* in case of errors */ 4528 expr_free_all(); 4529 return; 4530 } 4531 4532 /* expr() is also called in global initializations */ 4533 if (dcs->d_kind != DLK_EXTERN && !is_do_while) 4534 check_statement_reachable(stmt_kind); 4535 4536 check_expr_misc(tn, vctx, cond, !cond, false, false, false); 4537 if (tn->tn_op == ASSIGN && !tn->tn_parenthesized) { 4538 if (hflag && cond) 4539 /* assignment in conditional context */ 4540 warning(159); 4541 } else if (tn->tn_op == CON) { 4542 if (hflag && cond && !suppress_constcond && 4543 !tn->tn_system_dependent && 4544 !(is_do_while && 4545 is_constcond_false(tn, tn->tn_type->t_tspec))) 4546 /* constant in conditional context */ 4547 warning(161); 4548 } 4549 if (!modtab[tn->tn_op].m_has_side_effect) { 4550 /* 4551 * for left operands of COMMA this warning is already printed 4552 */ 4553 if (tn->tn_op != COMMA && !vctx && !cond) 4554 check_null_effect(tn); 4555 } 4556 debug_node(tn); 4557 4558 if (dofreeblk) 4559 expr_free_all(); 4560 } 4561 4562 /* If the expression has the form '*(arr + idx)', check the array index. */ 4563 static void 4564 check_array_index(const tnode_t *indir, bool taking_address) 4565 { 4566 const tnode_t *plus, *arr, *idx; 4567 4568 if (indir->tn_op == INDIR 4569 && (plus = indir->u.ops.left, plus->tn_op == PLUS) 4570 && plus->u.ops.left->tn_op == ADDR 4571 && (arr = plus->u.ops.left->u.ops.left, true) 4572 && (arr->tn_op == STRING || arr->tn_op == NAME) 4573 && arr->tn_type->t_tspec == ARRAY 4574 && (idx = plus->u.ops.right, idx->tn_op == CON) 4575 && (!is_incomplete(arr->tn_type) || idx->u.value.u.integer < 0)) 4576 goto proceed; 4577 return; 4578 4579 proceed:; 4580 int elsz = length_in_bits(arr->tn_type->t_subt, NULL); 4581 if (elsz == 0) 4582 return; 4583 elsz /= CHAR_SIZE; 4584 4585 /* Change the unit of the index from bytes to element size. */ 4586 int64_t con = is_uinteger(idx->tn_type->t_tspec) 4587 ? (int64_t)((uint64_t)idx->u.value.u.integer / elsz) 4588 : idx->u.value.u.integer / elsz; 4589 4590 int dim = arr->tn_type->u.dimension + (taking_address ? 1 : 0); 4591 4592 if (!is_uinteger(idx->tn_type->t_tspec) && con < 0) 4593 /* array subscript %jd cannot be negative */ 4594 warning(167, (intmax_t)con); 4595 else if (dim > 0 && (uint64_t)con >= (uint64_t)dim) 4596 /* array subscript %ju cannot be > %d */ 4597 warning(168, (uintmax_t)con, dim - 1); 4598 } 4599 4600 static void 4601 check_expr_addr(const tnode_t *ln, bool szof, bool fcall) 4602 { 4603 /* XXX: Taking warn_about_unreachable into account here feels wrong. */ 4604 if (ln->tn_op == NAME && (reached || !warn_about_unreachable)) { 4605 if (!szof) 4606 mark_as_set(ln->u.sym); 4607 mark_as_used(ln->u.sym, fcall, szof); 4608 } 4609 check_array_index(ln, true); 4610 } 4611 4612 /* 4613 * If there is an asm statement in one of the compound statements around, 4614 * there may be other side effects, so don't warn. 4615 */ 4616 static bool 4617 is_asm_around(void) 4618 { 4619 for (decl_level *dl = dcs; dl != NULL; dl = dl->d_enclosing) 4620 if (dl->d_asm) 4621 return true; 4622 return false; 4623 } 4624 4625 static void 4626 check_expr_side_effect(const tnode_t *ln, bool szof) 4627 { 4628 4629 /* XXX: Taking warn_about_unreachable into account here feels wrong. */ 4630 if (ln->tn_op == NAME && (reached || !warn_about_unreachable)) { 4631 scl_t sc = ln->u.sym->s_scl; 4632 if (sc != EXTERN && sc != STATIC && 4633 !ln->u.sym->s_set && !szof && !is_asm_around()) { 4634 /* '%s' may be used before set */ 4635 warning(158, ln->u.sym->s_name); 4636 mark_as_set(ln->u.sym); 4637 } 4638 mark_as_used(ln->u.sym, false, false); 4639 } 4640 } 4641 4642 static void 4643 check_expr_assign(const tnode_t *ln, bool szof) 4644 { 4645 /* XXX: Taking warn_about_unreachable into account here feels wrong. */ 4646 if (ln->tn_op == NAME && !szof && (reached || !warn_about_unreachable)) { 4647 mark_as_set(ln->u.sym); 4648 if (ln->u.sym->s_scl == EXTERN) 4649 outusg(ln->u.sym); 4650 } 4651 check_array_index(ln, false); 4652 } 4653 4654 static void 4655 check_expr_call(const tnode_t *tn, const tnode_t *ln, 4656 bool szof, bool vctx, bool cond, bool retval_discarded) 4657 { 4658 lint_assert(ln->tn_op == ADDR); 4659 lint_assert(ln->u.ops.left->tn_op == NAME); 4660 if (!szof && !is_compiler_builtin(ln->u.ops.left->u.sym->s_name)) 4661 outcall(tn, vctx || cond, retval_discarded); 4662 4663 const function_call *call = tn->u.call; 4664 if (call->args_len == 4 || call->args_len == 5) 4665 check_snprintb(call); 4666 } 4667 4668 static void 4669 check_expr_op(op_t op, const tnode_t *ln, bool szof, bool fcall, bool eqwarn) 4670 { 4671 switch (op) { 4672 case ADDR: 4673 check_expr_addr(ln, szof, fcall); 4674 break; 4675 case LOAD: 4676 check_array_index(ln, false); 4677 /* FALLTHROUGH */ 4678 case INCBEF: 4679 case DECBEF: 4680 case INCAFT: 4681 case DECAFT: 4682 case ADDASS: 4683 case SUBASS: 4684 case MULASS: 4685 case DIVASS: 4686 case MODASS: 4687 case ANDASS: 4688 case ORASS: 4689 case XORASS: 4690 case SHLASS: 4691 case SHRASS: 4692 case REAL: 4693 case IMAG: 4694 check_expr_side_effect(ln, szof); 4695 break; 4696 case ASSIGN: 4697 check_expr_assign(ln, szof); 4698 break; 4699 case EQ: 4700 if (hflag && eqwarn) 4701 /* operator '==' found where '=' was expected */ 4702 warning(160); 4703 break; 4704 default: 4705 break; 4706 } 4707 } 4708 4709 /* 4710 * vctx ??? 4711 * cond whether the expression is a condition that 4712 * will be compared with 0 4713 * eqwarn whether the operator '==' might be a 4714 * misspelled '=' 4715 * fcall whether the expression is a function call 4716 * retval_discarded whether the return value of a function call 4717 * is discarded; such calls will be analyzed by 4718 * lint2 in messages 4, 8 and 9 4719 * szof whether the expression is part of a sizeof 4720 * expression, which means that its value is 4721 * discarded since only the type is relevant 4722 */ 4723 void 4724 check_expr_misc(const tnode_t *tn, bool vctx, bool cond, 4725 bool eqwarn, bool fcall, bool retval_discarded, bool szof) 4726 { 4727 4728 if (tn == NULL) 4729 return; 4730 op_t op = tn->tn_op; 4731 if (op == NAME || op == CON || op == STRING) 4732 return; 4733 bool is_direct = op == CALL 4734 && tn->u.call->func->tn_op == ADDR 4735 && tn->u.call->func->u.ops.left->tn_op == NAME; 4736 if (op == CALL) { 4737 const function_call *call = tn->u.call; 4738 if (is_direct) 4739 check_expr_call(tn, call->func, 4740 szof, vctx, cond, retval_discarded); 4741 bool discard = op == CVT && tn->tn_type->t_tspec == VOID; 4742 check_expr_misc(call->func, false, false, false, is_direct, 4743 discard, szof); 4744 for (size_t i = 0, n = call->args_len; i < n; i++) 4745 check_expr_misc(call->args[i], 4746 true, false, false, false, false, szof); 4747 return; 4748 } 4749 4750 lint_assert(has_operands(tn)); 4751 tnode_t *ln = tn->u.ops.left; 4752 tnode_t *rn = tn->u.ops.right; 4753 check_expr_op(op, ln, szof, fcall, eqwarn); 4754 4755 const mod_t *mp = &modtab[op]; 4756 bool cvctx = mp->m_value_context; 4757 bool ccond = mp->m_compares_with_zero; 4758 bool eq = mp->m_warn_if_operand_eq && 4759 !ln->tn_parenthesized && 4760 rn != NULL && !rn->tn_parenthesized; 4761 4762 /* 4763 * Values of operands of ':' are not used if the type of at least 4764 * one of the operands (for GCC compatibility) is 'void'. 4765 * 4766 * XXX test/value context of QUEST should probably be used as 4767 * context for both operands of COLON. 4768 */ 4769 if (op == COLON && tn->tn_type->t_tspec == VOID) 4770 cvctx = ccond = false; 4771 bool discard = op == CVT && tn->tn_type->t_tspec == VOID; 4772 check_expr_misc(ln, cvctx, ccond, eq, is_direct, discard, szof); 4773 4774 switch (op) { 4775 case LOGAND: 4776 case LOGOR: 4777 check_expr_misc(rn, false, true, eq, false, false, szof); 4778 break; 4779 case COLON: 4780 check_expr_misc(rn, cvctx, ccond, eq, false, false, szof); 4781 break; 4782 case COMMA: 4783 check_expr_misc(rn, vctx, cond, false, false, false, szof); 4784 break; 4785 default: 4786 if (mp->m_binary) 4787 check_expr_misc(rn, true, false, eq, false, false, 4788 szof); 4789 break; 4790 } 4791 } 4792 4793 /* 4794 * Return whether the expression can be used for static initialization. 4795 * 4796 * Constant initialization expressions must be constant or an address 4797 * of a static object with an optional offset. In the first case, 4798 * the result is returned in *offsp. In the second case, the static 4799 * object is returned in *symp and the offset in *offsp. 4800 * 4801 * The expression can consist of PLUS, MINUS, ADDR, NAME, STRING and 4802 * CON. Type conversions are allowed if they do not change binary 4803 * representation (including width). 4804 * 4805 * C99 6.6 "Constant expressions" 4806 * C99 6.7.8p4 restricts initializers for static storage duration 4807 */ 4808 bool 4809 constant_addr(const tnode_t *tn, const sym_t **symp, ptrdiff_t *offsp) 4810 { 4811 const sym_t *sym; 4812 ptrdiff_t offs1, offs2; 4813 tspec_t t, ot; 4814 4815 switch (tn->tn_op) { 4816 case MINUS: 4817 if (tn->u.ops.right->tn_op == CVT) 4818 return constant_addr(tn->u.ops.right, symp, offsp); 4819 else if (tn->u.ops.right->tn_op != CON) 4820 return false; 4821 /* FALLTHROUGH */ 4822 case PLUS: 4823 offs1 = offs2 = 0; 4824 if (tn->u.ops.left->tn_op == CON) { 4825 offs1 = (ptrdiff_t)tn->u.ops.left->u.value.u.integer; 4826 if (!constant_addr(tn->u.ops.right, &sym, &offs2)) 4827 return false; 4828 } else if (tn->u.ops.right->tn_op == CON) { 4829 offs2 = (ptrdiff_t)tn->u.ops.right->u.value.u.integer; 4830 if (tn->tn_op == MINUS) 4831 offs2 = -offs2; 4832 if (!constant_addr(tn->u.ops.left, &sym, &offs1)) 4833 return false; 4834 } else { 4835 return false; 4836 } 4837 *symp = sym; 4838 *offsp = offs1 + offs2; 4839 return true; 4840 case ADDR: 4841 if (tn->u.ops.left->tn_op == NAME) { 4842 *symp = tn->u.ops.left->u.sym; 4843 *offsp = 0; 4844 return true; 4845 } else { 4846 /* 4847 * If this were the front end of a compiler, we would 4848 * return a label instead of 0, at least if 4849 * 'tn->u.ops.left->tn_op == STRING'. 4850 */ 4851 *symp = NULL; 4852 *offsp = 0; 4853 return true; 4854 } 4855 case CVT: 4856 t = tn->tn_type->t_tspec; 4857 ot = tn->u.ops.left->tn_type->t_tspec; 4858 if ((!is_integer(t) && t != PTR) || 4859 (!is_integer(ot) && ot != PTR)) { 4860 return false; 4861 } 4862 #if 0 4863 /*- 4864 * consider: 4865 * struct foo { 4866 * unsigned char a; 4867 * } f = { 4868 * (unsigned char)(unsigned long) 4869 * (&(((struct foo *)0)->a)) 4870 * }; 4871 * since psize(unsigned long) != psize(unsigned char), 4872 * this fails. 4873 */ 4874 else if (psize(t) != psize(ot)) 4875 return -1; 4876 #endif 4877 return constant_addr(tn->u.ops.left, symp, offsp); 4878 default: 4879 return false; 4880 } 4881 } 4882 4883 /* Append s2 to s1, then free s2. */ 4884 buffer * 4885 cat_strings(buffer *s1, buffer *s2) 4886 { 4887 4888 if ((s1->data != NULL) != (s2->data != NULL)) { 4889 /* cannot concatenate wide and regular string literals */ 4890 error(292); 4891 return s1; 4892 } 4893 4894 if (s1->data != NULL) { 4895 while (s1->len + s2->len + 1 > s1->cap) 4896 s1->cap *= 2; 4897 s1->data = xrealloc(s1->data, s1->cap); 4898 memcpy(s1->data + s1->len, s2->data, s2->len + 1); 4899 free(s2->data); 4900 } 4901 s1->len += s2->len; 4902 free(s2); 4903 4904 return s1; 4905 } 4906 4907 4908 typedef struct stmt_expr { 4909 memory_pool se_mem; 4910 sym_t *se_sym; 4911 struct stmt_expr *se_enclosing; 4912 } stmt_expr; 4913 4914 static stmt_expr *stmt_exprs; 4915 4916 void 4917 begin_statement_expr(void) 4918 { 4919 debug_enter(); 4920 4921 stmt_expr *se = xmalloc(sizeof(*se)); 4922 se->se_mem = expr_save_memory(); 4923 se->se_sym = NULL; 4924 se->se_enclosing = stmt_exprs; 4925 stmt_exprs = se; 4926 } 4927 4928 void 4929 do_statement_expr(tnode_t *tn) 4930 { 4931 block_level--; 4932 mem_block_level--; 4933 stmt_exprs->se_sym = tn != NULL 4934 ? mktempsym(block_dup_type(tn->tn_type)) 4935 : NULL; /* after a syntax error */ 4936 mem_block_level++; 4937 block_level++; 4938 /* '({ ... })' is a GCC extension */ 4939 gnuism(320); 4940 } 4941 4942 tnode_t * 4943 end_statement_expr(void) 4944 { 4945 tnode_t *tn; 4946 4947 stmt_expr *se = stmt_exprs; 4948 if (se->se_sym == NULL) { 4949 tn = NULL; /* after a syntax error */ 4950 goto end; 4951 } 4952 4953 tn = build_name(se->se_sym, false); 4954 (void)expr_save_memory(); /* leak */ 4955 expr_restore_memory(se->se_mem); 4956 stmt_exprs = se->se_enclosing; 4957 free(se); 4958 4959 end: 4960 debug_leave(); 4961 return tn; 4962 } 4963 4964 bool 4965 in_statement_expr(void) 4966 { 4967 return stmt_exprs != NULL; 4968 } 4969
Indexes created Mon Sep 22 13:09:51 GMT 2025