tree.c revision 1.663
1 /* $NetBSD: tree.c,v 1.663 2024/12/15 05:08:42 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 1.663 2024/12/15 05:08:42 rillig Exp $"); 41 #endif 42 43 #include <float.h> 44 #include <limits.h> 45 #include <math.h> 46 #include <signal.h> 47 #include <stdlib.h> 48 #include <string.h> 49 50 #include "lint1.h" 51 52 53 typedef struct integer_constraints { 54 int64_t smin; /* signed minimum */ 55 int64_t smax; /* signed maximum */ 56 uint64_t umin; /* unsigned minimum */ 57 uint64_t umax; /* unsigned maximum */ 58 uint64_t bclr; /* bits that are definitely clear */ 59 } integer_constraints; 60 61 62 static int64_t 63 s64_min(int64_t a, int64_t b) 64 { 65 return a < b ? a : b; 66 } 67 68 static int64_t 69 s64_max(int64_t a, int64_t b) 70 { 71 return a > b ? a : b; 72 } 73 74 static uint64_t 75 s64_abs(int64_t x) 76 { 77 return x >= 0 ? (uint64_t)x : -(uint64_t)x; 78 } 79 80 static uint64_t 81 u64_max(uint64_t a, uint64_t b) 82 { 83 return a > b ? a : b; 84 } 85 86 static uint64_t 87 u64_fill_right(uint64_t x) 88 { 89 x |= x >> 1; 90 x |= x >> 2; 91 x |= x >> 4; 92 x |= x >> 8; 93 x |= x >> 16; 94 x |= x >> 32; 95 return x; 96 } 97 98 static bool 99 str_ends_with(const char *haystack, const char *needle) 100 { 101 size_t hlen = strlen(haystack); 102 size_t nlen = strlen(needle); 103 104 return nlen <= hlen && 105 memcmp(haystack + hlen - nlen, needle, nlen) == 0; 106 } 107 108 static unsigned 109 width_in_bits(const type_t *tp) 110 { 111 112 lint_assert(is_integer(tp->t_tspec)); 113 return tp->t_bitfield 114 ? tp->t_bit_field_width 115 : size_in_bits(tp->t_tspec); 116 } 117 118 static int 119 portable_rank_cmp(tspec_t t1, tspec_t t2) 120 { 121 const ttab_t *p1 = type_properties(t1), *p2 = type_properties(t2); 122 lint_assert(p1->tt_rank_kind == p2->tt_rank_kind); 123 lint_assert(p1->tt_rank_value > 0); 124 lint_assert(p2->tt_rank_value > 0); 125 return (int)p1->tt_rank_value - (int)p2->tt_rank_value; 126 } 127 128 static bool 129 ic_maybe_signed(const type_t *tp, const integer_constraints *ic) 130 { 131 return !is_uinteger(tp->t_tspec) && ic->bclr >> 63 == 0; 132 } 133 134 static integer_constraints 135 ic_any(const type_t *tp) 136 { 137 integer_constraints c; 138 139 uint64_t vbits = value_bits(width_in_bits(tp)); 140 if (is_uinteger(tp->t_tspec)) { 141 c.smin = INT64_MIN; 142 c.smax = INT64_MAX; 143 c.umin = 0; 144 c.umax = vbits; 145 c.bclr = ~c.umax; 146 } else { 147 c.smin = (int64_t)-1 - (int64_t)(vbits >> 1); 148 c.smax = (int64_t)(vbits >> 1); 149 c.umin = 0; 150 c.umax = UINT64_MAX; 151 c.bclr = 0; 152 } 153 return c; 154 } 155 156 static integer_constraints 157 ic_mult(const type_t *tp, integer_constraints a, integer_constraints b) 158 { 159 integer_constraints c; 160 161 if (ic_maybe_signed(tp, &a) || ic_maybe_signed(tp, &b) 162 || (a.umax > 0 && b.umax > ic_any(tp).umax / a.umax)) 163 return ic_any(tp); 164 165 c.smin = INT64_MIN; 166 c.smax = INT64_MAX; 167 c.umin = a.umin * b.umin; 168 c.umax = a.umax * b.umax; 169 c.bclr = ~u64_fill_right(c.umax); 170 return c; 171 } 172 173 static integer_constraints 174 ic_div(const type_t *tp, integer_constraints a, integer_constraints b) 175 { 176 integer_constraints c; 177 178 if (ic_maybe_signed(tp, &a) || ic_maybe_signed(tp, &b) || b.umin == 0) 179 return ic_any(tp); 180 181 c.smin = INT64_MIN; 182 c.smax = INT64_MAX; 183 c.umin = a.umin / b.umax; 184 c.umax = a.umax / b.umin; 185 c.bclr = ~u64_fill_right(c.umax); 186 return c; 187 } 188 189 static integer_constraints 190 ic_mod_signed(integer_constraints a, integer_constraints b) 191 { 192 integer_constraints c; 193 194 uint64_t max_abs_b = u64_max(s64_abs(b.smin), s64_abs(b.smax)); 195 if (max_abs_b >> 63 != 0 || max_abs_b == 0) 196 return a; 197 c.smin = s64_max(a.smin, -(int64_t)(max_abs_b - 1)); 198 c.smax = s64_min(a.smax, (int64_t)(max_abs_b - 1)); 199 c.umin = 0; 200 c.umax = UINT64_MAX; 201 c.bclr = 0; 202 return c; 203 } 204 205 static integer_constraints 206 ic_mod(const type_t *tp, integer_constraints a, integer_constraints b) 207 { 208 integer_constraints c; 209 210 if (ic_maybe_signed(tp, &a) || ic_maybe_signed(tp, &b)) 211 return ic_mod_signed(a, b); 212 213 c.smin = INT64_MIN; 214 c.smax = INT64_MAX; 215 c.umin = 0; 216 c.umax = b.umax - 1; 217 c.bclr = ~u64_fill_right(c.umax); 218 return c; 219 } 220 221 static integer_constraints 222 ic_shl(const type_t *tp, integer_constraints a, integer_constraints b) 223 { 224 integer_constraints c; 225 unsigned int amount; 226 227 if (ic_maybe_signed(tp, &a)) 228 return ic_any(tp); 229 230 if (b.smin == b.smax && b.smin >= 0 && b.smin < 64) 231 amount = (unsigned int)b.smin; 232 else if (b.umin == b.umax && b.umin < 64) 233 amount = (unsigned int)b.umin; 234 else 235 return ic_any(tp); 236 237 c.smin = INT64_MIN; 238 c.smax = INT64_MAX; 239 c.umin = 0; 240 c.umax = UINT64_MAX; 241 c.bclr = a.bclr << amount | (((uint64_t)1 << amount) - 1); 242 return c; 243 } 244 245 static integer_constraints 246 ic_shr(const type_t *tp, integer_constraints a, integer_constraints b) 247 { 248 integer_constraints c; 249 unsigned int amount; 250 251 if (ic_maybe_signed(tp, &a)) 252 return ic_any(tp); 253 254 if (b.smin == b.smax && b.smin >= 0 && b.smin < 64) 255 amount = (unsigned int)b.smin; 256 else if (b.umin == b.umax && b.umin < 64) 257 amount = (unsigned int)b.umin; 258 else 259 return ic_any(tp); 260 261 c.smin = INT64_MIN; 262 c.smax = INT64_MAX; 263 c.umin = 0; 264 c.umax = UINT64_MAX; 265 c.bclr = a.bclr >> amount | ~(~(uint64_t)0 >> amount); 266 return c; 267 } 268 269 static integer_constraints 270 ic_bitand(integer_constraints a, integer_constraints b) 271 { 272 integer_constraints c; 273 274 c.smin = INT64_MIN; 275 c.smax = INT64_MAX; 276 c.umin = 0; 277 c.umax = ~(a.bclr | b.bclr); 278 if (c.umax >> 63 == 0) { 279 c.smin = 0; 280 c.smax = (int64_t)c.umax; 281 } 282 c.bclr = a.bclr | b.bclr; 283 return c; 284 } 285 286 static integer_constraints 287 ic_bitor(integer_constraints a, integer_constraints b) 288 { 289 integer_constraints c; 290 291 c.smin = INT64_MIN; 292 c.smax = INT64_MAX; 293 c.umin = 0; 294 c.umax = ~(a.bclr & b.bclr); 295 c.bclr = a.bclr & b.bclr; 296 return c; 297 } 298 299 static integer_constraints 300 ic_quest_colon(integer_constraints a, integer_constraints b) 301 { 302 integer_constraints c; 303 304 c.smin = a.smin < b.smin ? a.smin : b.smin; 305 c.smax = a.smax > b.smax ? a.smax : b.smax; 306 c.umin = a.umin < b.umin ? a.umin : b.umin; 307 c.umax = a.umax > b.umax ? a.umax : b.umax; 308 c.bclr = a.bclr & b.bclr; 309 return c; 310 } 311 312 static integer_constraints 313 ic_con(const type_t *tp, const val_t *v) 314 { 315 integer_constraints c; 316 317 lint_assert(is_integer(tp->t_tspec)); 318 int64_t si = v->u.integer; 319 uint64_t ui = (uint64_t)si; 320 c.smin = si; 321 c.smax = si; 322 c.umin = ui; 323 c.umax = ui; 324 c.bclr = ~ui; 325 return c; 326 } 327 328 static integer_constraints 329 ic_cvt(const type_t *ntp, const type_t *otp, integer_constraints a) 330 { 331 unsigned nw = width_in_bits(ntp); 332 unsigned ow = width_in_bits(otp); 333 bool nu = is_uinteger(ntp->t_tspec); 334 bool ou = is_uinteger(otp->t_tspec); 335 336 if (nw >= ow && nu == ou) 337 return a; 338 if (nw > ow && ou) 339 return a; 340 return ic_any(ntp); 341 } 342 343 static integer_constraints 344 ic_expr(const tnode_t *tn) 345 { 346 integer_constraints lc, rc; 347 348 lint_assert(is_integer(tn->tn_type->t_tspec)); 349 350 switch (tn->tn_op) { 351 case MULT: 352 lc = ic_expr(before_conversion(tn->u.ops.left)); 353 rc = ic_expr(before_conversion(tn->u.ops.right)); 354 return ic_mult(tn->tn_type, lc, rc); 355 case DIV: 356 lc = ic_expr(before_conversion(tn->u.ops.left)); 357 rc = ic_expr(before_conversion(tn->u.ops.right)); 358 return ic_div(tn->tn_type, lc, rc); 359 case MOD: 360 lc = ic_expr(before_conversion(tn->u.ops.left)); 361 rc = ic_expr(before_conversion(tn->u.ops.right)); 362 return ic_mod(tn->tn_type, lc, rc); 363 case SHL: 364 lc = ic_expr(tn->u.ops.left); 365 rc = ic_expr(tn->u.ops.right); 366 return ic_shl(tn->tn_type, lc, rc); 367 case SHR: 368 lc = ic_expr(tn->u.ops.left); 369 rc = ic_expr(tn->u.ops.right); 370 return ic_shr(tn->tn_type, lc, rc); 371 case BITAND: 372 lc = ic_expr(tn->u.ops.left); 373 rc = ic_expr(tn->u.ops.right); 374 return ic_bitand(lc, rc); 375 case BITOR: 376 lc = ic_expr(tn->u.ops.left); 377 rc = ic_expr(tn->u.ops.right); 378 return ic_bitor(lc, rc); 379 case QUEST: 380 lc = ic_expr(tn->u.ops.right->u.ops.left); 381 rc = ic_expr(tn->u.ops.right->u.ops.right); 382 return ic_quest_colon(lc, rc); 383 case CON: 384 return ic_con(tn->tn_type, &tn->u.value); 385 case CVT: 386 if (!is_integer(tn->u.ops.left->tn_type->t_tspec)) 387 return ic_any(tn->tn_type); 388 lc = ic_expr(tn->u.ops.left); 389 return ic_cvt(tn->tn_type, tn->u.ops.left->tn_type, lc); 390 default: 391 return ic_any(tn->tn_type); 392 } 393 } 394 395 uint64_t 396 possible_bits(const tnode_t *tn) 397 { 398 return ~ic_expr(tn).bclr; 399 } 400 401 bool 402 attributes_contain(const attribute_list *attrs, const char *str) 403 { 404 for (size_t i = 0, n = attrs->len; i < n; i++) { 405 const attribute *attr = attrs->attrs + i; 406 if (attr->prefix == NULL && strcmp(attr->name, str) == 0) 407 return true; 408 } 409 return false; 410 } 411 412 /* Build 'pointer to tp', 'array of tp' or 'function returning tp'. */ 413 type_t * 414 block_derive_type(type_t *tp, tspec_t t) 415 { 416 417 type_t *tp2 = block_zero_alloc(sizeof(*tp2), "type"); 418 tp2->t_tspec = t; 419 tp2->t_subt = tp; 420 return tp2; 421 } 422 423 /* 424 * Derive 'pointer to tp' or 'function returning tp'. 425 * The memory is freed at the end of the current expression. 426 */ 427 type_t * 428 expr_derive_type(type_t *tp, tspec_t t) 429 { 430 431 type_t *tp2 = expr_zero_alloc(sizeof(*tp2), "type"); 432 tp2->t_tspec = t; 433 tp2->t_subt = tp; 434 return tp2; 435 } 436 437 /* Create an expression from a unary or binary operator and its operands. */ 438 static tnode_t * 439 build_op(op_t op, bool sys, type_t *type, tnode_t *ln, tnode_t *rn) 440 { 441 442 tnode_t *ntn = expr_alloc_tnode(); 443 ntn->tn_op = op; 444 ntn->tn_type = type; 445 ntn->tn_sys = sys; 446 ntn->u.ops.left = ln; 447 ntn->u.ops.right = rn; 448 449 if (op == INDIR || op == FSEL) { 450 lint_assert(ln->tn_type->t_tspec == PTR); 451 tspec_t t = ln->tn_type->t_subt->t_tspec; 452 ntn->tn_lvalue = t != FUNC && t != VOID; 453 } 454 455 return ntn; 456 } 457 458 tnode_t * 459 build_constant(type_t *tp, val_t *v) 460 { 461 462 tnode_t *n = expr_alloc_tnode(); 463 n->tn_op = CON; 464 n->tn_type = tp; 465 n->u.value = *v; 466 n->u.value.v_tspec = tp->t_tspec; 467 free(v); 468 return n; 469 } 470 471 static tnode_t * 472 build_integer_constant(tspec_t t, int64_t si) 473 { 474 475 tnode_t *n = expr_alloc_tnode(); 476 n->tn_op = CON; 477 n->tn_type = gettyp(t); 478 n->u.value.v_tspec = t; 479 n->u.value.v_unsigned_since_c90 = false; 480 n->u.value.v_char_constant = false; 481 n->u.value.u.integer = si; 482 return n; 483 } 484 485 static void 486 fallback_symbol(sym_t *sym) 487 { 488 489 if (Tflag && fallback_symbol_strict_bool(sym)) 490 return; 491 492 if (funcsym != NULL && (strcmp(sym->s_name, "__FUNCTION__") == 0 || 493 strcmp(sym->s_name, "__PRETTY_FUNCTION__") == 0)) { 494 /* __FUNCTION__/__PRETTY_FUNCTION__ is a GCC extension */ 495 gnuism(316); 496 goto return_function_name; 497 } 498 499 if (funcsym != NULL && strcmp(sym->s_name, "__func__") == 0) { 500 if (!allow_c99) 501 /* __func__ is a C99 feature */ 502 warning(317); 503 /* C11 6.4.2.2 */ 504 return_function_name: 505 sym->s_type = block_derive_type(gettyp(CHAR), ARRAY); 506 sym->s_type->t_const = true; 507 sym->s_type->u.dimension = (int)strlen(funcsym->s_name) + 1; 508 return; 509 } 510 511 /* '%s' undefined */ 512 error(99, sym->s_name); 513 } 514 515 /* 516 * Functions that are predeclared by GCC or other compilers can be called 517 * with arbitrary arguments. Since lint usually runs after a successful 518 * compilation, it's the compiler's job to catch any errors. 519 */ 520 bool 521 is_compiler_builtin(const char *name) 522 { 523 /* https://gcc.gnu.org/onlinedocs/gcc/C-Extensions.html */ 524 if (allow_gcc) { 525 if (strncmp(name, "__atomic_", 9) == 0 || 526 strncmp(name, "__builtin_", 10) == 0 || 527 strcmp(name, "alloca") == 0 || 528 /* obsolete but still in use, as of 2021 */ 529 strncmp(name, "__sync_", 7) == 0) 530 return true; 531 } 532 533 /* https://software.intel.com/sites/landingpage/IntrinsicsGuide/ */ 534 if (strncmp(name, "_mm_", 4) == 0) 535 return true; 536 537 return false; 538 } 539 540 /* https://gcc.gnu.org/onlinedocs/gcc/Integer-Overflow-Builtins.html */ 541 static bool 542 is_gcc_bool_builtin(const char *name) 543 { 544 return strncmp(name, "__builtin_", 10) == 0 && 545 (str_ends_with(name, "_overflow") || 546 str_ends_with(name, "_overflow_p")); 547 } 548 549 static void 550 build_name_call(sym_t *sym) 551 { 552 553 if (is_compiler_builtin(sym->s_name)) { 554 /* 555 * Do not warn about these, just assume that they are regular 556 * functions compatible with non-prototype calling conventions. 557 */ 558 if (allow_gcc && is_gcc_bool_builtin(sym->s_name)) 559 sym->s_type = gettyp(BOOL); 560 } else if (allow_c99) 561 /* function '%s' implicitly declared to return int */ 562 error(215, sym->s_name); 563 else if (!allow_trad) 564 /* function '%s' implicitly declared to return int */ 565 warning(215, sym->s_name); 566 567 /* XXX if !allow_c90, the symbol should be exported to level 0 */ 568 sym->s_type = block_derive_type(sym->s_type, FUNC); 569 } 570 571 /* Create a node for a name (symbol table entry). */ 572 tnode_t * 573 build_name(sym_t *sym, bool is_funcname) 574 { 575 576 if (sym->s_scl == NO_SCL && !in_gcc_attribute) { 577 sym->s_scl = EXTERN; 578 sym->s_def = DECL; 579 if (is_funcname) 580 build_name_call(sym); 581 else 582 fallback_symbol(sym); 583 } 584 585 lint_assert(sym->s_kind == SK_VCFT || sym->s_kind == SK_MEMBER); 586 587 tnode_t *n = expr_alloc_tnode(); 588 n->tn_type = sym->s_type; 589 if (sym->s_scl == BOOL_CONST) { 590 n->tn_op = CON; 591 n->u.value.v_tspec = BOOL; 592 n->u.value.v_unsigned_since_c90 = false; 593 n->u.value.v_char_constant = false; 594 n->u.value.u.integer = sym->u.s_bool_constant ? 1 : 0; 595 } else if (sym->s_scl == ENUM_CONST) { 596 n->tn_op = CON; 597 n->u.value.v_tspec = INT; /* ENUM is in n->tn_type */ 598 n->u.value.v_unsigned_since_c90 = false; 599 n->u.value.v_char_constant = false; 600 n->u.value.u.integer = sym->u.s_enum_constant; 601 } else { 602 n->tn_op = NAME; 603 n->u.sym = sym; 604 if (sym->s_kind == SK_VCFT && sym->s_type->t_tspec != FUNC) 605 n->tn_lvalue = true; 606 } 607 608 return n; 609 } 610 611 tnode_t * 612 build_string(buffer *lit) 613 { 614 size_t value_len = lit->len; 615 if (lit->data != NULL) { 616 quoted_iterator it = { .end = 0 }; 617 for (value_len = 0; quoted_next(lit, &it); value_len++) 618 continue; 619 } 620 621 type_t *tp = expr_zero_alloc(sizeof(*tp), "type"); 622 tp->t_tspec = ARRAY; 623 tp->t_subt = gettyp(lit->data != NULL ? CHAR : WCHAR_TSPEC); 624 tp->u.dimension = (int)(value_len + 1); 625 626 tnode_t *n = expr_alloc_tnode(); 627 n->tn_op = STRING; 628 n->tn_type = tp; 629 n->tn_lvalue = true; 630 631 n->u.str_literals = expr_zero_alloc(sizeof(*n->u.str_literals), "tnode.string"); 632 n->u.str_literals->len = lit->len; 633 634 if (lit->data != NULL) { 635 n->u.str_literals->data = expr_zero_alloc(lit->len + 1, 636 "tnode.string.data"); 637 (void)memcpy(n->u.str_literals->data, lit->data, lit->len + 1); 638 free(lit->data); 639 } 640 free(lit); 641 642 return n; 643 } 644 645 tnode_t * 646 build_generic_selection(const tnode_t *expr, 647 struct generic_association *sel) 648 { 649 tnode_t *default_result = NULL; 650 651 for (; sel != NULL; sel = sel->ga_prev) { 652 if (expr != NULL && 653 types_compatible(sel->ga_arg, expr->tn_type, 654 false, false, NULL)) 655 return sel->ga_result; 656 else if (sel->ga_arg == NULL) 657 default_result = sel->ga_result; 658 } 659 return default_result; 660 } 661 662 static bool 663 is_out_of_char_range(const tnode_t *tn) 664 { 665 return tn->tn_op == CON && 666 !tn->u.value.v_char_constant && 667 !(0 <= tn->u.value.u.integer && 668 tn->u.value.u.integer < 1 << (CHAR_SIZE - 1)); 669 } 670 671 static bool 672 check_nonportable_char_comparison(op_t op, 673 const tnode_t *ln, tspec_t lt, 674 const tnode_t *rn, tspec_t rt) 675 { 676 if (!(hflag || pflag)) 677 return true; 678 679 if (lt == CHAR && is_out_of_char_range(rn)) { 680 char buf[128]; 681 (void)snprintf(buf, sizeof(buf), "%s %d", 682 op_name(op), (int)rn->u.value.u.integer); 683 /* nonportable character comparison '%s' */ 684 warning(230, buf); 685 return false; 686 } 687 if (rt == CHAR && is_out_of_char_range(ln)) { 688 char buf[128]; 689 (void)snprintf(buf, sizeof(buf), "%d %s ?", 690 (int)ln->u.value.u.integer, op_name(op)); 691 /* nonportable character comparison '%s' */ 692 warning(230, buf); 693 return false; 694 } 695 return true; 696 } 697 698 static void 699 check_integer_comparison(op_t op, tnode_t *ln, tnode_t *rn) 700 { 701 702 tspec_t lt = ln->tn_type->t_tspec; 703 tspec_t rt = rn->tn_type->t_tspec; 704 705 if (ln->tn_op != CON && rn->tn_op != CON) 706 return; 707 708 if (!is_integer(lt) || !is_integer(rt)) 709 return; 710 711 if (any_query_enabled && !in_system_header) { 712 if (lt == CHAR && rn->tn_op == CON && 713 !rn->u.value.v_char_constant) { 714 /* comparison '%s' of 'char' with plain integer %d */ 715 query_message(14, 716 op_name(op), (int)rn->u.value.u.integer); 717 } 718 if (rt == CHAR && ln->tn_op == CON && 719 !ln->u.value.v_char_constant) { 720 /* comparison '%s' of 'char' with plain integer %d */ 721 query_message(14, 722 op_name(op), (int)ln->u.value.u.integer); 723 } 724 } 725 726 if (!check_nonportable_char_comparison(op, ln, lt, rn, rt)) 727 return; 728 729 if (is_uinteger(lt) && !is_uinteger(rt) && 730 rn->tn_op == CON && rn->u.value.u.integer <= 0) { 731 if (rn->u.value.u.integer < 0) { 732 /* operator '%s' compares '%s' with '%s' */ 733 warning(162, op_name(op), 734 type_name(ln->tn_type), "negative constant"); 735 } else if (op == LT || op == GE) 736 /* operator '%s' compares '%s' with '%s' */ 737 warning(162, op_name(op), type_name(ln->tn_type), "0"); 738 return; 739 } 740 if (is_uinteger(rt) && !is_uinteger(lt) && 741 ln->tn_op == CON && ln->u.value.u.integer <= 0) { 742 if (ln->u.value.u.integer < 0) { 743 /* operator '%s' compares '%s' with '%s' */ 744 warning(162, op_name(op), 745 "negative constant", type_name(rn->tn_type)); 746 } else if (op == GT || op == LE) 747 /* operator '%s' compares '%s' with '%s' */ 748 warning(162, op_name(op), "0", type_name(rn->tn_type)); 749 return; 750 } 751 } 752 753 static const tspec_t arith_rank[] = { 754 LDOUBLE, DOUBLE, FLOAT, 755 #ifdef INT128_SIZE 756 UINT128, INT128, 757 #endif 758 ULLONG, LLONG, 759 ULONG, LONG, 760 UINT, INT, 761 }; 762 763 /* Keep unsigned in traditional C */ 764 static tspec_t 765 usual_arithmetic_conversion_trad(tspec_t lt, tspec_t rt) 766 { 767 768 size_t i; 769 for (i = 0; arith_rank[i] != INT; i++) 770 if (lt == arith_rank[i] || rt == arith_rank[i]) 771 break; 772 773 tspec_t t = arith_rank[i]; 774 if (is_uinteger(lt) || is_uinteger(rt)) 775 if (is_integer(t) && !is_uinteger(t)) 776 return unsigned_type(t); 777 return t; 778 } 779 780 static tspec_t 781 usual_arithmetic_conversion_c90(tspec_t lt, tspec_t rt) 782 { 783 784 if (lt == rt) 785 return lt; 786 787 if (lt == LCOMPLEX || rt == LCOMPLEX) 788 return LCOMPLEX; 789 if (lt == DCOMPLEX || rt == DCOMPLEX) 790 return DCOMPLEX; 791 if (lt == FCOMPLEX || rt == FCOMPLEX) 792 return FCOMPLEX; 793 if (lt == LDOUBLE || rt == LDOUBLE) 794 return LDOUBLE; 795 if (lt == DOUBLE || rt == DOUBLE) 796 return DOUBLE; 797 if (lt == FLOAT || rt == FLOAT) 798 return FLOAT; 799 800 if (size_in_bits(lt) > size_in_bits(rt)) 801 return lt; 802 if (size_in_bits(lt) < size_in_bits(rt)) 803 return rt; 804 805 size_t i; 806 for (i = 3; arith_rank[i] != INT; i++) 807 if (arith_rank[i] == lt || arith_rank[i] == rt) 808 break; 809 if ((is_uinteger(lt) || is_uinteger(rt)) && 810 !is_uinteger(arith_rank[i])) 811 i--; 812 return arith_rank[i]; 813 } 814 815 static tnode_t * 816 apply_usual_arithmetic_conversions(op_t op, tnode_t *tn, tspec_t t) 817 { 818 type_t *ntp = expr_dup_type(tn->tn_type); 819 ntp->t_tspec = t; 820 if (tn->tn_op != CON) { 821 /* usual arithmetic conversion for '%s' from '%s' to '%s' */ 822 query_message(4, op_name(op), 823 type_name(tn->tn_type), type_name(ntp)); 824 } 825 return convert(op, 0, ntp, tn); 826 } 827 828 /* 829 * Apply the "usual arithmetic conversions" (C99 6.3.1.8), which gives both 830 * operands the same type. 831 */ 832 static void 833 balance(op_t op, tnode_t **lnp, tnode_t **rnp) 834 { 835 836 tspec_t lt = (*lnp)->tn_type->t_tspec; 837 tspec_t rt = (*rnp)->tn_type->t_tspec; 838 if (!is_arithmetic(lt) || !is_arithmetic(rt)) 839 return; 840 841 tspec_t t = allow_c90 842 ? usual_arithmetic_conversion_c90(lt, rt) 843 : usual_arithmetic_conversion_trad(lt, rt); 844 845 if (modtab[op].m_comparison 846 && is_integer(lt) && (*lnp)->tn_op != CON 847 && is_floating(t) && (*rnp)->tn_op == CON) 848 /* comparing integer '%s' to floating point constant %Lg */ 849 warning(379, type_name((*lnp)->tn_type), 850 (*rnp)->u.value.u.floating); 851 852 if (t != lt) 853 *lnp = apply_usual_arithmetic_conversions(op, *lnp, t); 854 if (t != rt) 855 *rnp = apply_usual_arithmetic_conversions(op, *rnp, t); 856 857 if (is_integer(t)) { 858 unsigned lw = width_in_bits((*lnp)->tn_type); 859 unsigned rw = width_in_bits((*rnp)->tn_type); 860 if (lw < rw) 861 *lnp = convert(NOOP, 0, (*rnp)->tn_type, *lnp); 862 if (rw < lw) 863 *rnp = convert(NOOP, 0, (*lnp)->tn_type, *rnp); 864 } 865 } 866 867 static tnode_t * 868 build_address(bool sys, tnode_t *tn, bool force) 869 { 870 tspec_t t; 871 872 if (!force && ((t = tn->tn_type->t_tspec) == ARRAY || t == FUNC)) { 873 if (!allow_c90) 874 /* '&' before array or function: ignored */ 875 warning(127); 876 return tn; 877 } 878 879 /* eliminate '&*' */ 880 if (tn->tn_op == INDIR && 881 tn->u.ops.left->tn_type->t_tspec == PTR && 882 tn->u.ops.left->tn_type->t_subt == tn->tn_type) { 883 return tn->u.ops.left; 884 } 885 886 return build_op(ADDR, sys, expr_derive_type(tn->tn_type, PTR), 887 tn, NULL); 888 } 889 890 static uint64_t 891 fold_unsigned_integer(op_t op, uint64_t l, uint64_t r, 892 uint64_t max_value, bool *overflow) 893 { 894 switch (op) { 895 case COMPL: 896 return ~l & max_value; 897 case UPLUS: 898 return +l; 899 case UMINUS: 900 return -l & max_value; 901 case MULT: 902 *overflow = r > 0 && l > max_value / r; 903 return l * r; 904 case DIV: 905 if (r == 0) { 906 /* division by 0 */ 907 error(139); 908 return max_value; 909 } 910 return l / r; 911 case MOD: 912 if (r == 0) { 913 /* modulus by 0 */ 914 error(140); 915 return 0; 916 } 917 return l % r; 918 case PLUS: 919 *overflow = l > max_value - r; 920 return l + r; 921 case MINUS: 922 *overflow = l < r; 923 return l - r; 924 case SHL: 925 /* TODO: warn about out-of-bounds 'r'. */ 926 /* TODO: warn about overflow. */ 927 return l << (r & 63); 928 case SHR: 929 /* TODO: warn about out-of-bounds 'r'. */ 930 return l >> (r & 63); 931 case LT: 932 return l < r ? 1 : 0; 933 case LE: 934 return l <= r ? 1 : 0; 935 case GT: 936 return l > r ? 1 : 0; 937 case GE: 938 return l >= r ? 1 : 0; 939 case EQ: 940 return l == r ? 1 : 0; 941 case NE: 942 return l != r ? 1 : 0; 943 case BITAND: 944 return l & r; 945 case BITXOR: 946 return l ^ r; 947 case BITOR: 948 return l | r; 949 default: 950 lint_assert(/*CONSTCOND*/false); 951 /* NOTREACHED */ 952 } 953 } 954 955 static int64_t 956 fold_signed_integer(op_t op, int64_t l, int64_t r, 957 int64_t min_value, int64_t max_value, bool *overflow) 958 { 959 switch (op) { 960 case COMPL: 961 return ~l; 962 case UPLUS: 963 return +l; 964 case UMINUS: 965 *overflow = l == min_value; 966 return *overflow ? l : -l; 967 case MULT:; 968 uint64_t al = l >= 0 ? (uint64_t)l : -(uint64_t)l; 969 uint64_t ar = r >= 0 ? (uint64_t)r : -(uint64_t)r; 970 bool neg = (l >= 0) != (r >= 0); 971 uint64_t max_prod = (uint64_t)max_value + (neg ? 1 : 0); 972 if (al > 0 && ar > max_prod / al) { 973 *overflow = true; 974 return neg ? min_value : max_value; 975 } 976 return l * r; 977 case DIV: 978 if (r == 0) { 979 /* division by 0 */ 980 error(139); 981 return max_value; 982 } 983 if (l == min_value && r == -1) { 984 *overflow = true; 985 return l; 986 } 987 return l / r; 988 case MOD: 989 if (r == 0) { 990 /* modulus by 0 */ 991 error(140); 992 return 0; 993 } 994 if (l == min_value && r == -1) { 995 *overflow = true; 996 return 0; 997 } 998 return l % r; 999 case PLUS: 1000 if (r > 0 && l > max_value - r) { 1001 *overflow = true; 1002 return max_value; 1003 } 1004 if (r < 0 && l < min_value - r) { 1005 *overflow = true; 1006 return min_value; 1007 } 1008 return l + r; 1009 case MINUS: 1010 if (r > 0 && l < min_value + r) { 1011 *overflow = true; 1012 return min_value; 1013 } 1014 if (r < 0 && l > max_value + r) { 1015 *overflow = true; 1016 return max_value; 1017 } 1018 return l - r; 1019 case SHL: 1020 /* TODO: warn about out-of-bounds 'r'. */ 1021 /* TODO: warn about overflow. */ 1022 return l << (r & 63); 1023 case SHR: 1024 /* TODO: warn about out-of-bounds 'r'. */ 1025 if (l < 0) 1026 return (int64_t)~(~(uint64_t)l >> (r & 63)); 1027 return (int64_t)((uint64_t)l >> (r & 63)); 1028 case LT: 1029 return l < r ? 1 : 0; 1030 case LE: 1031 return l <= r ? 1 : 0; 1032 case GT: 1033 return l > r ? 1 : 0; 1034 case GE: 1035 return l >= r ? 1 : 0; 1036 case EQ: 1037 return l == r ? 1 : 0; 1038 case NE: 1039 return l != r ? 1 : 0; 1040 case BITAND: 1041 return l & r; 1042 case BITXOR: 1043 return l ^ r; 1044 case BITOR: 1045 return l | r; 1046 default: 1047 lint_assert(/*CONSTCOND*/false); 1048 /* NOTREACHED */ 1049 } 1050 } 1051 1052 static tnode_t * 1053 fold_constant_integer(tnode_t *tn) 1054 { 1055 1056 lint_assert(has_operands(tn)); 1057 tspec_t t = tn->u.ops.left->tn_type->t_tspec; 1058 int64_t l = tn->u.ops.left->u.value.u.integer; 1059 int64_t r = is_binary(tn) ? tn->u.ops.right->u.value.u.integer : 0; 1060 uint64_t mask = value_bits(size_in_bits(t)); 1061 1062 int64_t res; 1063 bool overflow = false; 1064 if (!is_integer(t) || is_uinteger(t)) { 1065 uint64_t u_res = fold_unsigned_integer(tn->tn_op, 1066 (uint64_t)l, (uint64_t)r, mask, &overflow); 1067 if (u_res > mask) 1068 overflow = true; 1069 res = (int64_t)u_res; 1070 if (overflow && hflag) { 1071 char buf[128]; 1072 if (is_binary(tn)) { 1073 snprintf(buf, sizeof(buf), "%ju %s %ju", 1074 (uintmax_t)l, op_name(tn->tn_op), 1075 (uintmax_t)r); 1076 } else { 1077 snprintf(buf, sizeof(buf), "%s%ju", 1078 op_name(tn->tn_op), (uintmax_t)l); 1079 } 1080 /* '%s' overflows '%s' */ 1081 warning(141, buf, type_name(tn->tn_type)); 1082 } 1083 } else { 1084 int64_t max_value = (int64_t)(mask >> 1); 1085 int64_t min_value = -max_value - 1; 1086 res = fold_signed_integer(tn->tn_op, 1087 l, r, min_value, max_value, &overflow); 1088 if (res < min_value || res > max_value) 1089 overflow = true; 1090 if (overflow && hflag) { 1091 char buf[128]; 1092 if (is_binary(tn)) { 1093 snprintf(buf, sizeof(buf), "%jd %s %jd", 1094 (intmax_t)l, op_name(tn->tn_op), 1095 (intmax_t)r); 1096 } else if (tn->tn_op == UMINUS && l < 0) { 1097 snprintf(buf, sizeof(buf), "-(%jd)", 1098 (intmax_t)l); 1099 } else { 1100 snprintf(buf, sizeof(buf), "%s%jd", 1101 op_name(tn->tn_op), (intmax_t)l); 1102 } 1103 /* '%s' overflows '%s' */ 1104 warning(141, buf, type_name(tn->tn_type)); 1105 } 1106 } 1107 1108 val_t *v = xcalloc(1, sizeof(*v)); 1109 v->v_tspec = tn->tn_type->t_tspec; 1110 v->u.integer = convert_integer(res, t, size_in_bits(t)); 1111 1112 tnode_t *cn = build_constant(tn->tn_type, v); 1113 if (tn->u.ops.left->tn_system_dependent) 1114 cn->tn_system_dependent = true; 1115 if (is_binary(tn) && tn->u.ops.right->tn_system_dependent) 1116 cn->tn_system_dependent = true; 1117 1118 return cn; 1119 } 1120 1121 static tnode_t * 1122 build_struct_access(op_t op, bool sys, tnode_t *ln, tnode_t *rn) 1123 { 1124 1125 lint_assert(rn->tn_op == NAME); 1126 lint_assert(is_member(rn->u.sym)); 1127 1128 bool lvalue = op == ARROW || ln->tn_lvalue; 1129 1130 if (op == POINT) 1131 ln = build_address(sys, ln, true); 1132 else if (ln->tn_type->t_tspec != PTR) { 1133 lint_assert(!allow_c90); 1134 lint_assert(is_integer(ln->tn_type->t_tspec)); 1135 ln = convert(NOOP, 0, expr_derive_type(gettyp(VOID), PTR), ln); 1136 } 1137 1138 tnode_t *ctn = build_integer_constant(PTRDIFF_TSPEC, 1139 rn->u.sym->u.s_member.sm_offset_in_bits / CHAR_SIZE); 1140 1141 type_t *ptr_tp = expr_derive_type(rn->tn_type, PTR); 1142 tnode_t *ntn = build_op(PLUS, sys, ptr_tp, ln, ctn); 1143 if (ln->tn_op == CON) 1144 ntn = fold_constant_integer(ntn); 1145 1146 op_t nop = rn->tn_type->t_bitfield ? FSEL : INDIR; 1147 ntn = build_op(nop, sys, ntn->tn_type->t_subt, ntn, NULL); 1148 if (!lvalue) 1149 ntn->tn_lvalue = false; 1150 1151 return ntn; 1152 } 1153 1154 /* 1155 * Get the size in bytes of type tp->t_subt, as a constant expression of type 1156 * ptrdiff_t as seen from the target platform. 1157 */ 1158 static tnode_t * 1159 subt_size_in_bytes(type_t *tp) 1160 { 1161 1162 lint_assert(tp->t_tspec == PTR); 1163 tp = tp->t_subt; 1164 1165 int elem = 1; 1166 while (tp->t_tspec == ARRAY) { 1167 elem *= tp->u.dimension; 1168 tp = tp->t_subt; 1169 } 1170 1171 int elsz_in_bits = 0; 1172 switch (tp->t_tspec) { 1173 case FUNC: 1174 /* pointer to function is not allowed here */ 1175 error(110); 1176 break; 1177 case VOID: 1178 /* cannot do pointer arithmetic on operand of unknown size */ 1179 gnuism(136); 1180 break; 1181 case STRUCT: 1182 case UNION: 1183 if ((elsz_in_bits = (int)tp->u.sou->sou_size_in_bits) == 0) 1184 /* cannot do pointer arithmetic on operand of ... */ 1185 error(136); 1186 break; 1187 case ENUM: 1188 if (is_incomplete(tp)) 1189 /* cannot do pointer arithmetic on operand of ... */ 1190 warning(136); 1191 /* FALLTHROUGH */ 1192 default: 1193 if ((elsz_in_bits = size_in_bits(tp->t_tspec)) == 0) 1194 /* cannot do pointer arithmetic on operand of ... */ 1195 error(136); 1196 else 1197 lint_assert(elsz_in_bits != -1); 1198 break; 1199 } 1200 1201 if (elem == 0 && elsz_in_bits != 0) 1202 /* cannot do pointer arithmetic on operand of unknown size */ 1203 error(136); 1204 1205 if (elsz_in_bits == 0) 1206 elsz_in_bits = CHAR_SIZE; 1207 1208 return build_integer_constant(PTRDIFF_TSPEC, 1209 (int64_t)(elem * elsz_in_bits / CHAR_SIZE)); 1210 } 1211 1212 static tnode_t * 1213 build_prepost_incdec(op_t op, bool sys, tnode_t *ln) 1214 { 1215 1216 lint_assert(ln != NULL); 1217 tnode_t *cn = ln->tn_type->t_tspec == PTR 1218 ? subt_size_in_bytes(ln->tn_type) 1219 : build_integer_constant(INT, 1); 1220 return build_op(op, sys, ln->tn_type, ln, cn); 1221 } 1222 1223 static void 1224 check_enum_array_index(const tnode_t *ln, const tnode_t *rn) 1225 { 1226 1227 if (ln->tn_op != ADDR || ln->u.ops.left->tn_op != NAME) 1228 return; 1229 1230 const type_t *ltp = ln->u.ops.left->tn_type; 1231 if (ltp->t_tspec != ARRAY || ltp->t_incomplete_array) 1232 return; 1233 1234 if (rn->tn_op != CVT || !rn->tn_type->t_is_enum) 1235 return; 1236 if (rn->u.ops.left->tn_op != LOAD) 1237 return; 1238 1239 const type_t *rtp = rn->u.ops.left->tn_type; 1240 const sym_t *ec = rtp->u.enumer->en_first_enumerator; 1241 const sym_t *max_ec = ec; 1242 lint_assert(ec != NULL); 1243 for (ec = ec->s_next; ec != NULL; ec = ec->s_next) 1244 if (ec->u.s_enum_constant > max_ec->u.s_enum_constant) 1245 max_ec = ec; 1246 1247 int64_t max_enum_value = max_ec->u.s_enum_constant; 1248 lint_assert(INT_MIN <= max_enum_value && max_enum_value <= INT_MAX); 1249 1250 int max_array_index = ltp->u.dimension - 1; 1251 if (max_enum_value == max_array_index) 1252 return; 1253 1254 if (max_enum_value == max_array_index + 1 && 1255 (strstr(max_ec->s_name, "MAX") != NULL || 1256 strstr(max_ec->s_name, "max") != NULL || 1257 strstr(max_ec->s_name, "NUM") != NULL || 1258 strstr(max_ec->s_name, "num") != NULL || 1259 strncmp(max_ec->s_name, "N_", 2) == 0)) 1260 return; 1261 1262 /* maximum value %d for '%s' of type '%s' does not match maximum array index %d */ 1263 warning(348, (int)max_enum_value, max_ec->s_name, type_name(rtp), 1264 max_array_index); 1265 print_previous_declaration(max_ec); 1266 } 1267 1268 static tnode_t * 1269 build_plus_minus(op_t op, bool sys, tnode_t *ln, tnode_t *rn) 1270 { 1271 1272 if (rn->tn_type->t_tspec == PTR && is_integer(ln->tn_type->t_tspec)) { 1273 tnode_t *tmp = ln; 1274 ln = rn; 1275 rn = tmp; 1276 /* pointer addition has integer on the left-hand side */ 1277 query_message(5); 1278 } 1279 1280 /* pointer +- integer */ 1281 tspec_t lt = ln->tn_type->t_tspec; 1282 tspec_t rt = rn->tn_type->t_tspec; 1283 if (lt == PTR && rt != PTR) { 1284 lint_assert(is_integer(rt)); 1285 1286 check_ctype_macro_invocation(ln, rn); 1287 check_enum_array_index(ln, rn); 1288 1289 tnode_t *elsz = subt_size_in_bytes(ln->tn_type); 1290 tspec_t szt = elsz->tn_type->t_tspec; 1291 if (rt != szt && rt != unsigned_type(szt)) 1292 rn = convert(NOOP, 0, elsz->tn_type, rn); 1293 1294 tnode_t *prod = build_op(MULT, sys, rn->tn_type, rn, elsz); 1295 if (rn->tn_op == CON) 1296 prod = fold_constant_integer(prod); 1297 1298 return build_op(op, sys, ln->tn_type, ln, prod); 1299 } 1300 1301 /* pointer - pointer */ 1302 if (rt == PTR) { 1303 lint_assert(lt == PTR); 1304 lint_assert(op == MINUS); 1305 1306 type_t *ptrdiff = gettyp(PTRDIFF_TSPEC); 1307 tnode_t *raw_diff = build_op(op, sys, ptrdiff, ln, rn); 1308 if (ln->tn_op == CON && rn->tn_op == CON) 1309 raw_diff = fold_constant_integer(raw_diff); 1310 1311 tnode_t *elsz = subt_size_in_bytes(ln->tn_type); 1312 balance(NOOP, &raw_diff, &elsz); 1313 1314 return build_op(DIV, sys, ptrdiff, raw_diff, elsz); 1315 } 1316 1317 return build_op(op, sys, ln->tn_type, ln, rn); 1318 } 1319 1320 static tnode_t * 1321 build_bit_shift(op_t op, bool sys, tnode_t *ln, tnode_t *rn) 1322 { 1323 1324 if (!allow_c90 && rn->tn_type->t_tspec != INT) 1325 // XXX: C1978 7.5 says: "Both [operators] perform the usual 1326 // arithmetic conversions on their operands." 1327 // TODO: Add a test to exercise this part of the code. 1328 rn = convert(NOOP, 0, gettyp(INT), rn); 1329 return build_op(op, sys, ln->tn_type, ln, rn); 1330 } 1331 1332 static bool 1333 is_null_pointer(const tnode_t *tn) 1334 { 1335 tspec_t t = tn->tn_type->t_tspec; 1336 1337 // TODO: Investigate how other pointers are stored, in particular, 1338 // whether a pointer constant can have a non-zero value. 1339 // If not, simplify the code below. 1340 return ((t == PTR && tn->tn_type->t_subt->t_tspec == VOID) 1341 || is_integer(t)) 1342 && (tn->tn_op == CON && tn->u.value.u.integer == 0); 1343 } 1344 1345 /* Return a type based on tp1, with added qualifiers from tp2. */ 1346 static type_t * 1347 merge_qualifiers(type_t *tp1, const type_t *tp2) 1348 { 1349 1350 lint_assert(tp1->t_tspec == PTR); 1351 lint_assert(tp2->t_tspec == PTR); 1352 1353 bool c1 = tp1->t_subt->t_const; 1354 bool c2 = tp2->t_subt->t_const; 1355 bool v1 = tp1->t_subt->t_volatile; 1356 bool v2 = tp2->t_subt->t_volatile; 1357 1358 if (c1 == (c1 | c2) && v1 == (v1 | v2)) 1359 return tp1; 1360 1361 type_t *nstp = expr_dup_type(tp1->t_subt); 1362 nstp->t_const |= c2; 1363 nstp->t_volatile |= v2; 1364 1365 type_t *ntp = expr_dup_type(tp1); 1366 ntp->t_subt = nstp; 1367 return ntp; 1368 } 1369 1370 /* See C99 6.5.15 "Conditional operator". */ 1371 static tnode_t * 1372 build_colon(bool sys, tnode_t *ln, tnode_t *rn) 1373 { 1374 tspec_t lt = ln->tn_type->t_tspec; 1375 tspec_t rt = rn->tn_type->t_tspec; 1376 1377 type_t *tp; 1378 if (is_arithmetic(lt) && is_arithmetic(rt)) 1379 /* The operands were already balanced in build_binary. */ 1380 tp = ln->tn_type; 1381 else if (lt == BOOL && rt == BOOL) 1382 tp = ln->tn_type; 1383 else if (lt == VOID || rt == VOID) 1384 tp = gettyp(VOID); 1385 else if (is_struct_or_union(lt)) { 1386 lint_assert(is_struct_or_union(rt)); 1387 lint_assert(ln->tn_type->u.sou == rn->tn_type->u.sou); 1388 if (is_incomplete(ln->tn_type)) { 1389 /* unknown operand size, op '%s' */ 1390 error(138, op_name(COLON)); 1391 return NULL; 1392 } 1393 tp = ln->tn_type; 1394 } else if (lt == PTR && is_integer(rt)) { 1395 if (rt != PTRDIFF_TSPEC) 1396 rn = convert(NOOP, 0, gettyp(PTRDIFF_TSPEC), rn); 1397 tp = ln->tn_type; 1398 } else if (rt == PTR && is_integer(lt)) { 1399 if (lt != PTRDIFF_TSPEC) 1400 ln = convert(NOOP, 0, gettyp(PTRDIFF_TSPEC), ln); 1401 tp = rn->tn_type; 1402 } else if (lt == PTR && is_null_pointer(rn)) 1403 tp = merge_qualifiers(ln->tn_type, rn->tn_type); 1404 else if (rt == PTR && is_null_pointer(ln)) 1405 tp = merge_qualifiers(rn->tn_type, ln->tn_type); 1406 else if (lt == PTR && ln->tn_type->t_subt->t_tspec == VOID) 1407 tp = merge_qualifiers(ln->tn_type, rn->tn_type); 1408 else if (rt == PTR && rn->tn_type->t_subt->t_tspec == VOID) 1409 tp = merge_qualifiers(rn->tn_type, ln->tn_type); 1410 else { 1411 /* 1412 * XXX For now we simply take the left type. This is probably 1413 * wrong, if one type contains a function prototype and the 1414 * other one, at the same place, only an old-style declaration. 1415 */ 1416 tp = merge_qualifiers(ln->tn_type, rn->tn_type); 1417 } 1418 1419 return build_op(COLON, sys, tp, ln, rn); 1420 } 1421 1422 /* TODO: check for varargs */ 1423 static bool 1424 is_cast_redundant(const tnode_t *tn) 1425 { 1426 const type_t *ntp = tn->tn_type, *otp = tn->u.ops.left->tn_type; 1427 tspec_t nt = ntp->t_tspec, ot = otp->t_tspec; 1428 1429 if (nt == BOOL || ot == BOOL) 1430 return nt == BOOL && ot == BOOL; 1431 1432 if (is_integer(nt) && is_integer(ot)) { 1433 unsigned int nw = width_in_bits(ntp), ow = width_in_bits(otp); 1434 if (is_uinteger(nt) == is_uinteger(ot)) 1435 return nw >= ow; 1436 return is_uinteger(ot) && nw > ow; 1437 } 1438 1439 if (is_complex(nt) || is_complex(ot)) 1440 return is_complex(nt) && is_complex(ot) && 1441 size_in_bits(nt) >= size_in_bits(ot); 1442 1443 if (is_floating(nt) && is_floating(ot)) 1444 return size_in_bits(nt) >= size_in_bits(ot); 1445 1446 if (nt == PTR && ot == PTR) { 1447 if (!ntp->t_subt->t_const && otp->t_subt->t_const) 1448 return false; 1449 if (!ntp->t_subt->t_volatile && otp->t_subt->t_volatile) 1450 return false; 1451 1452 if (ntp->t_subt->t_tspec == VOID || 1453 otp->t_subt->t_tspec == VOID || 1454 types_compatible(ntp->t_subt, otp->t_subt, 1455 false, false, NULL)) 1456 return true; 1457 } 1458 1459 return false; 1460 } 1461 1462 static bool 1463 is_assignment(op_t op) 1464 { 1465 1466 return op == ASSIGN || 1467 op == MULASS || 1468 op == DIVASS || 1469 op == MODASS || 1470 op == ADDASS || 1471 op == SUBASS || 1472 op == SHLASS || 1473 op == SHRASS || 1474 op == ANDASS || 1475 op == XORASS || 1476 op == ORASS || 1477 op == RETURN || 1478 op == INIT; 1479 } 1480 1481 static tnode_t * 1482 build_assignment(op_t op, bool sys, tnode_t *ln, tnode_t *rn) 1483 { 1484 1485 tspec_t lt = ln->tn_type->t_tspec; 1486 tspec_t rt = rn->tn_type->t_tspec; 1487 1488 if (is_assignment(rn->tn_op)) 1489 /* chained assignment with '%s' and '%s' */ 1490 query_message(10, op_name(op), op_name(rn->tn_op)); 1491 1492 if ((op == ADDASS || op == SUBASS) && lt == PTR) { 1493 lint_assert(is_integer(rt)); 1494 tnode_t *ctn = subt_size_in_bytes(ln->tn_type); 1495 if (rn->tn_type->t_tspec != ctn->tn_type->t_tspec) 1496 rn = convert(NOOP, 0, ctn->tn_type, rn); 1497 rn = build_op(MULT, sys, rn->tn_type, rn, ctn); 1498 if (rn->u.ops.left->tn_op == CON) 1499 rn = fold_constant_integer(rn); 1500 } 1501 1502 if ((op == ASSIGN || op == RETURN || op == INIT) && 1503 (lt == STRUCT || rt == STRUCT)) { 1504 lint_assert(lt == rt); 1505 lint_assert(ln->tn_type->u.sou == rn->tn_type->u.sou); 1506 if (is_incomplete(ln->tn_type)) { 1507 if (op == RETURN) 1508 /* cannot return incomplete type */ 1509 error(212); 1510 else 1511 /* unknown operand size, op '%s' */ 1512 error(138, op_name(op)); 1513 return NULL; 1514 } 1515 } 1516 1517 if (op == SHLASS && hflag && allow_trad && allow_c90 1518 && portable_rank_cmp(lt, rt) < 0) 1519 /* semantics of '%s' change in C90; ... */ 1520 warning(118, "<<="); 1521 1522 if (op != SHLASS && op != SHRASS 1523 && (op == ASSIGN || lt != PTR) 1524 && (lt != rt || (ln->tn_type->t_bitfield && rn->tn_op == CON))) { 1525 rn = convert(op, 0, ln->tn_type, rn); 1526 rt = lt; 1527 } 1528 1529 if (lt == PTR && ln->tn_type->t_subt->t_tspec != VOID 1530 && rt == PTR && rn->tn_type->t_subt->t_tspec == VOID 1531 && !is_null_pointer(rn)) 1532 /* implicit narrowing conversion from void ... */ 1533 query_message(20, type_name(ln->tn_type)); 1534 1535 if (any_query_enabled && rn->tn_op == CVT && rn->tn_cast && 1536 types_compatible(ln->tn_type, rn->tn_type, false, false, NULL) && 1537 is_cast_redundant(rn)) { 1538 /* redundant cast from '%s' to '%s' before assignment */ 1539 query_message(7, type_name(rn->u.ops.left->tn_type), 1540 type_name(rn->tn_type)); 1541 } 1542 1543 return build_op(op, sys, ln->tn_type, ln, rn); 1544 } 1545 1546 static tnode_t * 1547 build_real_imag(op_t op, bool sys, tnode_t *ln) 1548 { 1549 1550 lint_assert(ln != NULL); 1551 if (ln->tn_op == NAME) { 1552 /* 1553 * This may be too much, but it avoids wrong warnings. See 1554 * d_c99_complex_split.c. 1555 */ 1556 mark_as_used(ln->u.sym, false, false); 1557 mark_as_set(ln->u.sym); 1558 } 1559 1560 tspec_t t; 1561 switch (ln->tn_type->t_tspec) { 1562 case LCOMPLEX: 1563 t = LDOUBLE; 1564 break; 1565 case DCOMPLEX: 1566 t = DOUBLE; 1567 break; 1568 case FCOMPLEX: 1569 t = FLOAT; 1570 break; 1571 default: 1572 /* '__%s__' is illegal for type '%s' */ 1573 error(276, op == REAL ? "real" : "imag", 1574 type_name(ln->tn_type)); 1575 return NULL; 1576 } 1577 1578 tnode_t *ntn = build_op(op, sys, gettyp(t), ln, NULL); 1579 ntn->tn_lvalue = true; 1580 return ntn; 1581 } 1582 1583 static bool 1584 is_confusing_precedence(op_t op, op_t lop, op_t rop, op_t *cop) 1585 { 1586 1587 if (op == SHL || op == SHR) { 1588 if (lop == PLUS || lop == MINUS) 1589 return *cop = lop, true; 1590 if (rop == PLUS || rop == MINUS) 1591 return *cop = rop, true; 1592 return false; 1593 } 1594 1595 if (op == LOGOR) { 1596 if (lop == LOGAND) 1597 return *cop = lop, true; 1598 if (rop == LOGAND) 1599 return *cop = rop, true; 1600 return false; 1601 } 1602 1603 lint_assert(op == BITAND || op == BITXOR || op == BITOR); 1604 if (lop != op 1605 && (lop == PLUS || lop == MINUS || lop == BITAND || lop == BITXOR)) 1606 return *cop = lop, true; 1607 if (rop != op 1608 && (rop == PLUS || rop == MINUS || rop == BITAND || rop == BITXOR)) 1609 return *cop = rop, true; 1610 return false; 1611 } 1612 1613 /* 1614 * Print a warning if the given node has operands which should be 1615 * parenthesized. 1616 * 1617 * XXX Does not work if an operand is a constant expression. Constant 1618 * expressions are already folded. 1619 */ 1620 static void 1621 check_precedence_confusion(tnode_t *tn) 1622 { 1623 tnode_t *ln, *rn; 1624 1625 if (!hflag) 1626 return; 1627 1628 debug_node(tn); 1629 1630 lint_assert(is_binary(tn)); 1631 for (ln = tn->u.ops.left; ln->tn_op == CVT; ln = ln->u.ops.left) 1632 continue; 1633 for (rn = tn->u.ops.right; rn->tn_op == CVT; rn = rn->u.ops.left) 1634 continue; 1635 1636 op_t cop; 1637 if (is_confusing_precedence(tn->tn_op, 1638 ln->tn_parenthesized ? NOOP : ln->tn_op, 1639 rn->tn_parenthesized ? NOOP : rn->tn_op, &cop)) { 1640 /* possible precedence confusion between '%s' and '%s' */ 1641 warning(169, op_name(tn->tn_op), op_name(cop)); 1642 } 1643 } 1644 1645 static tnode_t * 1646 fold_constant_compare_zero(tnode_t *tn) 1647 { 1648 1649 val_t *v = xcalloc(1, sizeof(*v)); 1650 v->v_tspec = tn->tn_type->t_tspec; 1651 lint_assert(v->v_tspec == INT || (Tflag && v->v_tspec == BOOL)); 1652 1653 lint_assert(has_operands(tn)); 1654 bool l = constant_is_nonzero(tn->u.ops.left); 1655 bool r = is_binary(tn) && constant_is_nonzero(tn->u.ops.right); 1656 1657 switch (tn->tn_op) { 1658 case NOT: 1659 if (hflag && !suppress_constcond) 1660 /* constant operand to '!' */ 1661 warning(239); 1662 v->u.integer = !l ? 1 : 0; 1663 break; 1664 case LOGAND: 1665 v->u.integer = l && r ? 1 : 0; 1666 break; 1667 case LOGOR: 1668 v->u.integer = l || r ? 1 : 0; 1669 break; 1670 default: 1671 lint_assert(/*CONSTCOND*/false); 1672 } 1673 1674 return build_constant(tn->tn_type, v); 1675 } 1676 1677 static long double 1678 floating_error_value(tspec_t t, long double lv) 1679 { 1680 if (t == FLOAT) 1681 return lv < 0 ? -FLT_MAX : FLT_MAX; 1682 if (t == DOUBLE) 1683 return lv < 0 ? -DBL_MAX : DBL_MAX; 1684 /* 1685 * When NetBSD is cross-built in MKLINT=yes mode on x86_64 for sparc64, 1686 * tools/lint checks this code while building usr.bin/xlint. In that 1687 * situation, lint uses the preprocessor for sparc64, in which the type 1688 * 'long double' is IEEE-754-binary128, affecting the macro LDBL_MAX 1689 * below. The type 'long double', as well as the strtold 1690 * implementation, comes from the host platform x86_64 though, where 1691 * 'long double' consumes 128 bits as well but only uses 80 of them. 1692 * The exponent range of the two 'long double' types is the same, but 1693 * the maximum finite value differs due to the extended precision on 1694 * sparc64. 1695 * 1696 * To properly handle the data types of the target platform, lint would 1697 * have to implement the floating-point types in a platform-independent 1698 * way, which is not worth the effort, given how few programs 1699 * practically use 'long double'. 1700 */ 1701 /* LINTED 248: floating-point constant out of range */ 1702 long double max = LDBL_MAX; 1703 return lv < 0 ? -max : max; 1704 } 1705 1706 static bool 1707 is_floating_overflow(tspec_t t, long double val) 1708 { 1709 if (fpe != 0 || isfinite(val) == 0) 1710 return true; 1711 if (t == FLOAT && (val > FLT_MAX || val < -FLT_MAX)) 1712 return true; 1713 if (t == DOUBLE && (val > DBL_MAX || val < -DBL_MAX)) 1714 return true; 1715 return false; 1716 } 1717 1718 static tnode_t * 1719 fold_constant_floating(tnode_t *tn) 1720 { 1721 1722 fpe = 0; 1723 1724 tspec_t t = tn->tn_type->t_tspec; 1725 1726 val_t *v = xcalloc(1, sizeof(*v)); 1727 v->v_tspec = t; 1728 1729 lint_assert(is_floating(t)); 1730 lint_assert(has_operands(tn)); 1731 lint_assert(t == tn->u.ops.left->tn_type->t_tspec); 1732 lint_assert(!is_binary(tn) || t == tn->u.ops.right->tn_type->t_tspec); 1733 1734 long double lv = tn->u.ops.left->u.value.u.floating; 1735 long double rv = is_binary(tn) ? tn->u.ops.right->u.value.u.floating 1736 : 0.0; 1737 1738 switch (tn->tn_op) { 1739 case UPLUS: 1740 v->u.floating = lv; 1741 break; 1742 case UMINUS: 1743 v->u.floating = -lv; 1744 break; 1745 case MULT: 1746 v->u.floating = lv * rv; 1747 break; 1748 case DIV: 1749 if (rv == 0.0) { 1750 /* division by 0 */ 1751 error(139); 1752 v->u.floating = floating_error_value(t, lv); 1753 } else { 1754 v->u.floating = lv / rv; 1755 } 1756 break; 1757 case PLUS: 1758 v->u.floating = lv + rv; 1759 break; 1760 case MINUS: 1761 v->u.floating = lv - rv; 1762 break; 1763 case LT: 1764 v->u.integer = lv < rv ? 1 : 0; 1765 break; 1766 case LE: 1767 v->u.integer = lv <= rv ? 1 : 0; 1768 break; 1769 case GE: 1770 v->u.integer = lv >= rv ? 1 : 0; 1771 break; 1772 case GT: 1773 v->u.integer = lv > rv ? 1 : 0; 1774 break; 1775 case EQ: 1776 v->u.integer = lv == rv ? 1 : 0; 1777 break; 1778 case NE: 1779 v->u.integer = lv != rv ? 1 : 0; 1780 break; 1781 default: 1782 lint_assert(/*CONSTCOND*/false); 1783 } 1784 1785 // XXX: Must not access u.floating after setting u.integer. 1786 lint_assert(fpe != 0 || isnan(v->u.floating) == 0); 1787 if (is_complex(v->v_tspec)) { 1788 /* 1789 * Don't warn, as lint doesn't model the imaginary part of 1790 * complex numbers. 1791 */ 1792 fpe = 0; 1793 } else if (is_floating_overflow(t, v->u.floating)) { 1794 /* operator '%s' produces floating point overflow */ 1795 warning(142, op_name(tn->tn_op)); 1796 v->u.floating = floating_error_value(t, v->u.floating); 1797 fpe = 0; 1798 } 1799 1800 return build_constant(tn->tn_type, v); 1801 } 1802 1803 static void 1804 use(const tnode_t *tn) 1805 { 1806 if (tn == NULL) 1807 return; 1808 switch (tn->tn_op) { 1809 case NAME: 1810 mark_as_used(tn->u.sym, false /* XXX */, false /* XXX */); 1811 break; 1812 case CON: 1813 case STRING: 1814 break; 1815 case CALL:; 1816 const function_call *call = tn->u.call; 1817 for (size_t i = 0, n = call->args_len; i < n; i++) 1818 use(call->args[i]); 1819 break; 1820 default: 1821 lint_assert(has_operands(tn)); 1822 use(tn->u.ops.left); 1823 if (is_binary(tn)) 1824 use(tn->u.ops.right); 1825 } 1826 } 1827 1828 /* 1829 * Create a tree node for a binary operator and its two operands. Also called 1830 * for unary operators; in that case rn is NULL. 1831 * 1832 * Function calls, sizeof and casts are handled elsewhere. 1833 */ 1834 tnode_t * 1835 build_binary(tnode_t *ln, op_t op, bool sys, tnode_t *rn) 1836 { 1837 const mod_t *mp = &modtab[op]; 1838 1839 /* If there was an error in one of the operands, return. */ 1840 if (ln == NULL || (mp->m_binary && rn == NULL)) 1841 return NULL; 1842 1843 if (mp->m_value_context || mp->m_compares_with_zero) 1844 ln = cconv(ln); 1845 if (mp->m_binary && op != ARROW && op != POINT) 1846 rn = cconv(rn); 1847 1848 if (mp->m_comparison) 1849 check_integer_comparison(op, ln, rn); 1850 1851 if (mp->m_value_context || mp->m_compares_with_zero) 1852 ln = promote(op, false, ln); 1853 if (mp->m_binary && op != ARROW && op != POINT && 1854 op != ASSIGN && op != RETURN && op != INIT) 1855 rn = promote(op, false, rn); 1856 1857 if (mp->m_warn_if_left_unsigned_in_c90 && 1858 ln->tn_op == CON && ln->u.value.v_unsigned_since_c90) { 1859 /* C90 treats constant as unsigned, op '%s' */ 1860 warning(218, op_name(op)); 1861 ln->u.value.v_unsigned_since_c90 = false; 1862 } 1863 if (mp->m_warn_if_right_unsigned_in_c90 && 1864 rn->tn_op == CON && rn->u.value.v_unsigned_since_c90) { 1865 /* C90 treats constant as unsigned, op '%s' */ 1866 warning(218, op_name(op)); 1867 rn->u.value.v_unsigned_since_c90 = false; 1868 } 1869 1870 if (mp->m_balance_operands || (!allow_c90 && (op == SHL || op == SHR))) 1871 balance(op, &ln, &rn); 1872 1873 if (!typeok(op, 0, ln, rn)) 1874 return NULL; 1875 1876 tnode_t *ntn; 1877 switch (op) { 1878 case POINT: 1879 case ARROW: 1880 ntn = build_struct_access(op, sys, ln, rn); 1881 break; 1882 case NOT: 1883 if (ln->tn_op == ASSIGN && ln->u.ops.right->tn_op == CON) { 1884 /* constant assignment of type '%s' in operand ... */ 1885 warning(382, type_name(ln->tn_type), 1886 is_nonzero_val(&ln->u.ops.right->u.value) 1887 ? "true" : "false"); 1888 } 1889 ntn = build_op(op, sys, gettyp(Tflag ? BOOL : INT), ln, NULL); 1890 break; 1891 case INCAFT: 1892 case DECAFT: 1893 case INCBEF: 1894 case DECBEF: 1895 ntn = build_prepost_incdec(op, sys, ln); 1896 break; 1897 case ADDR: 1898 ntn = build_address(sys, ln, false); 1899 break; 1900 case INDIR: 1901 ntn = build_op(INDIR, sys, ln->tn_type->t_subt, ln, NULL); 1902 break; 1903 case PLUS: 1904 case MINUS: 1905 ntn = build_plus_minus(op, sys, ln, rn); 1906 break; 1907 case SHL: 1908 case SHR: 1909 ntn = build_bit_shift(op, sys, ln, rn); 1910 break; 1911 case COLON: 1912 ntn = build_colon(sys, ln, rn); 1913 break; 1914 case ASSIGN: 1915 case MULASS: 1916 case DIVASS: 1917 case MODASS: 1918 case ADDASS: 1919 case SUBASS: 1920 case SHLASS: 1921 case SHRASS: 1922 case ANDASS: 1923 case XORASS: 1924 case ORASS: 1925 case RETURN: 1926 case INIT: 1927 ntn = build_assignment(op, sys, ln, rn); 1928 break; 1929 case COMMA: 1930 /* comma operator with types '%s' and '%s' */ 1931 query_message(12, 1932 type_name(ln->tn_type), type_name(rn->tn_type)); 1933 /* FALLTHROUGH */ 1934 case QUEST: 1935 ntn = build_op(op, sys, rn->tn_type, ln, rn); 1936 break; 1937 case REAL: 1938 case IMAG: 1939 ntn = build_real_imag(op, sys, ln); 1940 break; 1941 default: 1942 lint_assert(mp->m_binary == (rn != NULL)); 1943 type_t *rettp = mp->m_returns_bool 1944 ? gettyp(Tflag ? BOOL : INT) : ln->tn_type; 1945 ntn = build_op(op, sys, rettp, ln, rn); 1946 break; 1947 } 1948 1949 if (ntn == NULL) 1950 return NULL; 1951 1952 if (mp->m_possible_precedence_confusion) 1953 check_precedence_confusion(ntn); 1954 1955 if (hflag && !suppress_constcond && 1956 mp->m_compares_with_zero && 1957 (ln->tn_op == CON || 1958 (mp->m_binary && op != QUEST && rn->tn_op == CON)) && 1959 /* XXX: rn->tn_system_dependent should be checked as well */ 1960 !ln->tn_system_dependent) 1961 /* constant in conditional context */ 1962 warning(161); 1963 1964 if (mp->m_fold_constant_operands && ln->tn_op == CON) { 1965 if (!mp->m_binary || rn->tn_op == CON) { 1966 if (mp->m_compares_with_zero) 1967 ntn = fold_constant_compare_zero(ntn); 1968 else if (is_floating(ntn->tn_type->t_tspec)) 1969 ntn = fold_constant_floating(ntn); 1970 else 1971 ntn = fold_constant_integer(ntn); 1972 } else if (op == QUEST) { 1973 lint_assert(has_operands(rn)); 1974 use(ln->u.value.u.integer != 0 1975 ? rn->u.ops.right : rn->u.ops.left); 1976 ntn = ln->u.value.u.integer != 0 1977 ? rn->u.ops.left : rn->u.ops.right; 1978 } 1979 } 1980 1981 return ntn; 1982 } 1983 1984 tnode_t * 1985 build_unary(op_t op, bool sys, tnode_t *tn) 1986 { 1987 return build_binary(tn, op, sys, NULL); 1988 } 1989 1990 static bool 1991 are_members_compatible(const sym_t *a, const sym_t *b) 1992 { 1993 if (a->u.s_member.sm_offset_in_bits != b->u.s_member.sm_offset_in_bits) 1994 return false; 1995 1996 const type_t *atp = a->s_type; 1997 const type_t *btp = b->s_type; 1998 bool w = false; 1999 if (!types_compatible(atp, btp, false, false, &w) && !w) 2000 return false; 2001 if (a->s_bitfield != b->s_bitfield) 2002 return false; 2003 if (a->s_bitfield) { 2004 if (atp->t_bit_field_width != btp->t_bit_field_width) 2005 return false; 2006 if (atp->t_bit_field_offset != btp->t_bit_field_offset) 2007 return false; 2008 } 2009 return true; 2010 } 2011 2012 /* 2013 * Return whether all struct/union members with the same name have the same 2014 * type and offset. 2015 */ 2016 static bool 2017 all_members_compatible(const sym_t *msym) 2018 { 2019 for (const sym_t *csym = msym; 2020 csym != NULL; csym = csym->s_symtab_next) { 2021 if (!is_member(csym)) 2022 continue; 2023 if (strcmp(msym->s_name, csym->s_name) != 0) 2024 continue; 2025 2026 for (const sym_t *sym = csym->s_symtab_next; 2027 sym != NULL; sym = sym->s_symtab_next) { 2028 if (is_member(sym) 2029 && strcmp(csym->s_name, sym->s_name) == 0 2030 && !are_members_compatible(csym, sym)) 2031 return false; 2032 } 2033 } 2034 return true; 2035 } 2036 2037 sym_t * 2038 find_member(const struct_or_union *sou, const char *name) 2039 { 2040 for (sym_t *mem = sou->sou_first_member; 2041 mem != NULL; mem = mem->s_next) { 2042 lint_assert(is_member(mem)); 2043 lint_assert(mem->u.s_member.sm_containing_type == sou); 2044 if (strcmp(mem->s_name, name) == 0) 2045 return mem; 2046 } 2047 2048 for (sym_t *mem = sou->sou_first_member; 2049 mem != NULL; mem = mem->s_next) { 2050 if (is_struct_or_union(mem->s_type->t_tspec) 2051 && mem->s_name == unnamed) { 2052 sym_t *nested_mem = 2053 find_member(mem->s_type->u.sou, name); 2054 if (nested_mem != NULL) 2055 return nested_mem; 2056 } 2057 } 2058 return NULL; 2059 } 2060 2061 /* 2062 * Remove the member if it was unknown until now, which means 2063 * that no defined struct or union has a member with the same name. 2064 */ 2065 static void 2066 remove_unknown_member(tnode_t *tn, sym_t *msym) 2067 { 2068 /* type '%s' does not have member '%s' */ 2069 error(101, type_name(tn->tn_type), msym->s_name); 2070 symtab_remove_forever(msym); 2071 msym->s_kind = SK_MEMBER; 2072 msym->s_scl = STRUCT_MEMBER; 2073 2074 struct_or_union *sou = expr_zero_alloc(sizeof(*sou), 2075 "struct_or_union"); 2076 sou->sou_tag = expr_zero_alloc(sizeof(*sou->sou_tag), "sym"); 2077 sou->sou_tag->s_name = unnamed; 2078 2079 msym->u.s_member.sm_containing_type = sou; 2080 /* 2081 * The member sm_offset_in_bits is not needed here since this symbol 2082 * can only be used for error reporting. 2083 */ 2084 } 2085 2086 /* 2087 * Returns a symbol which has the same name as 'msym' and is a member of the 2088 * struct or union specified by 'tn'. 2089 */ 2090 static sym_t * 2091 struct_or_union_member(tnode_t *tn, op_t op, sym_t *msym) 2092 { 2093 2094 /* Determine the tag type of which msym is expected to be a member. */ 2095 const type_t *tp = NULL; 2096 if (op == POINT && is_struct_or_union(tn->tn_type->t_tspec)) 2097 tp = tn->tn_type; 2098 if (op == ARROW && tn->tn_type->t_tspec == PTR 2099 && is_struct_or_union(tn->tn_type->t_subt->t_tspec)) 2100 tp = tn->tn_type->t_subt; 2101 struct_or_union *sou = tp != NULL ? tp->u.sou : NULL; 2102 2103 if (sou != NULL) { 2104 sym_t *nested_mem = find_member(sou, msym->s_name); 2105 if (nested_mem != NULL) 2106 return nested_mem; 2107 } 2108 2109 if (msym->s_scl == NO_SCL) { 2110 remove_unknown_member(tn, msym); 2111 return msym; 2112 } 2113 2114 bool eq = all_members_compatible(msym); 2115 2116 /* 2117 * Now handle the case in which the left operand refers really to a 2118 * struct/union, but the right operand is not member of it. 2119 */ 2120 if (sou != NULL) { 2121 if (eq && !allow_c90) 2122 /* illegal use of member '%s' */ 2123 warning(102, msym->s_name); 2124 else 2125 /* illegal use of member '%s' */ 2126 error(102, msym->s_name); 2127 return msym; 2128 } 2129 2130 if (eq) { 2131 if (op == POINT) { 2132 if (!allow_c90) 2133 /* left operand of '.' must be struct ... */ 2134 warning(103, type_name(tn->tn_type)); 2135 else 2136 /* left operand of '.' must be struct ... */ 2137 error(103, type_name(tn->tn_type)); 2138 } else { 2139 if (!allow_c90 && tn->tn_type->t_tspec == PTR) 2140 /* left operand of '->' must be pointer ... */ 2141 warning(104, type_name(tn->tn_type)); 2142 else 2143 /* left operand of '->' must be pointer ... */ 2144 error(104, type_name(tn->tn_type)); 2145 } 2146 } else { 2147 if (!allow_c90) 2148 /* non-unique member requires struct/union %s */ 2149 error(105, op == POINT ? "object" : "pointer"); 2150 else 2151 /* unacceptable operand of '%s' */ 2152 error(111, op_name(op)); 2153 } 2154 2155 return msym; 2156 } 2157 2158 tnode_t * 2159 build_member_access(tnode_t *ln, op_t op, bool sys, sbuf_t *member) 2160 { 2161 sym_t *msym; 2162 2163 if (ln == NULL) 2164 return NULL; 2165 2166 if (op == ARROW) 2167 /* must do this before struct_or_union_member is called */ 2168 ln = cconv(ln); 2169 msym = struct_or_union_member(ln, op, getsym(member)); 2170 return build_binary(ln, op, sys, build_name(msym, false)); 2171 } 2172 2173 /* 2174 * Perform class conversions. 2175 * 2176 * Arrays of type T are converted into pointers to type T. 2177 * Functions are converted to pointers to functions. 2178 * Lvalues are converted to rvalues. 2179 * 2180 * C99 6.3 "Conversions" 2181 * C99 6.3.2 "Other operands" 2182 * C99 6.3.2.1 "Lvalues, arrays, and function designators" 2183 */ 2184 tnode_t * 2185 cconv(tnode_t *tn) 2186 { 2187 if (tn->tn_type->t_tspec == ARRAY) { 2188 if (!tn->tn_lvalue) { 2189 /* XXX print correct operator */ 2190 /* %soperand of '%s' must be lvalue */ 2191 gnuism(114, "", op_name(ADDR)); 2192 } 2193 tn = build_op(ADDR, tn->tn_sys, 2194 expr_derive_type(tn->tn_type->t_subt, PTR), tn, NULL); 2195 } 2196 2197 if (tn->tn_type->t_tspec == FUNC) 2198 tn = build_address(tn->tn_sys, tn, true); 2199 2200 if (tn->tn_lvalue) { 2201 type_t *tp = expr_dup_type(tn->tn_type); 2202 /* C99 6.3.2.1p2 sentence 2 says to remove the qualifiers. */ 2203 tp->t_const = tp->t_volatile = false; 2204 tn = build_op(LOAD, tn->tn_sys, tp, tn, NULL); 2205 } 2206 2207 return tn; 2208 } 2209 2210 const tnode_t * 2211 before_conversion(const tnode_t *tn) 2212 { 2213 while (tn->tn_op == CVT && !tn->tn_cast) 2214 tn = tn->u.ops.left; 2215 return tn; 2216 } 2217 2218 /* 2219 * Most errors required by C90 are reported in struct_or_union_member(). 2220 * Here we only check for totally wrong things. 2221 */ 2222 static bool 2223 typeok_point(const tnode_t *ln, const type_t *ltp, tspec_t lt) 2224 { 2225 if (is_struct_or_union(lt)) 2226 return true; 2227 2228 if (lt == FUNC || lt == VOID || ltp->t_bitfield) 2229 goto wrong; 2230 2231 /* 2232 * Some C dialects from before C90 tolerated any lvalue on the 2233 * left-hand side of the '.' operator, allowing things like 'char 2234 * st[100]; st.st_mtime', assuming that the member 'st_mtime' only 2235 * occurred in a single struct; see typeok_arrow. 2236 */ 2237 if (ln->tn_lvalue) 2238 return true; 2239 2240 wrong: 2241 /* With allow_c90 we already got an error */ 2242 if (!allow_c90) 2243 /* unacceptable operand of '%s' */ 2244 error(111, op_name(POINT)); 2245 2246 return false; 2247 } 2248 2249 static bool 2250 typeok_arrow(tspec_t lt) 2251 { 2252 /* 2253 * C1978 Appendix A 14.1 says: <quote>In fact, any lvalue is allowed 2254 * before '.', and that lvalue is then assumed to have the form of the 2255 * structure of which the name of the right is a member. [...] Such 2256 * constructions are non-portable.</quote> 2257 */ 2258 if (lt == PTR || (!allow_c90 && is_integer(lt))) 2259 return true; 2260 2261 /* With allow_c90 we already got an error */ 2262 if (!allow_c90) 2263 /* unacceptable operand of '%s' */ 2264 error(111, op_name(ARROW)); 2265 return false; 2266 } 2267 2268 static bool 2269 typeok_incdec(op_t op, const tnode_t *tn, const type_t *tp) 2270 { 2271 /* operand has scalar type (checked in typeok) */ 2272 if (!tn->tn_lvalue) { 2273 if (tn->tn_op == CVT && tn->tn_cast && 2274 tn->u.ops.left->tn_op == LOAD) 2275 /* a cast does not yield an lvalue */ 2276 error(163); 2277 /* %soperand of '%s' must be lvalue */ 2278 error(114, "", op_name(op)); 2279 return false; 2280 } 2281 if (tp->t_const && allow_c90) 2282 /* %soperand of '%s' must be modifiable lvalue */ 2283 warning(115, "", op_name(op)); 2284 return true; 2285 } 2286 2287 static bool 2288 typeok_address(op_t op, const tnode_t *tn, const type_t *tp, tspec_t t) 2289 { 2290 if (t == ARRAY || t == FUNC) { 2291 /* ok, a warning comes later (in build_address()) */ 2292 } else if (!tn->tn_lvalue) { 2293 if (tn->tn_op == CVT && tn->tn_cast && 2294 tn->u.ops.left->tn_op == LOAD) 2295 /* a cast does not yield an lvalue */ 2296 error(163); 2297 /* %soperand of '%s' must be lvalue */ 2298 error(114, "", op_name(op)); 2299 return false; 2300 } else if (is_scalar(t)) { 2301 if (tp->t_bitfield) { 2302 /* cannot take address of bit-field */ 2303 error(112); 2304 return false; 2305 } 2306 } else if (t != STRUCT && t != UNION) { 2307 /* unacceptable operand of '%s' */ 2308 error(111, op_name(op)); 2309 return false; 2310 } 2311 if (tn->tn_op == NAME && tn->u.sym->s_register) { 2312 /* cannot take address of register '%s' */ 2313 error(113, tn->u.sym->s_name); 2314 return false; 2315 } 2316 return true; 2317 } 2318 2319 static bool 2320 typeok_indir(const type_t *tp, tspec_t t) 2321 { 2322 2323 if (t != PTR) { 2324 /* cannot dereference non-pointer type '%s' */ 2325 error(96, type_name(tp)); 2326 return false; 2327 } 2328 return true; 2329 } 2330 2331 static void 2332 warn_incompatible_types(op_t op, 2333 const type_t *ltp, tspec_t lt, 2334 const type_t *rtp, tspec_t rt) 2335 { 2336 bool binary = modtab[op].m_binary; 2337 2338 if (lt == VOID || (binary && rt == VOID)) { 2339 /* void type illegal in expression */ 2340 error(109); 2341 } else if (op == ASSIGN) 2342 /* cannot assign to '%s' from '%s' */ 2343 error(171, type_name(ltp), type_name(rtp)); 2344 else if (binary) 2345 /* operands of '%s' have incompatible types '%s' and '%s' */ 2346 error(107, op_name(op), type_name(ltp), type_name(rtp)); 2347 else { 2348 lint_assert(rt == NO_TSPEC); 2349 /* operand of '%s' has invalid type '%s' */ 2350 error(108, op_name(op), type_name(ltp)); 2351 } 2352 } 2353 2354 static bool 2355 typeok_plus(op_t op, 2356 const type_t *ltp, tspec_t lt, 2357 const type_t *rtp, tspec_t rt) 2358 { 2359 /* operands have scalar types (checked in typeok) */ 2360 if ((lt == PTR && !is_integer(rt)) || (rt == PTR && !is_integer(lt))) { 2361 warn_incompatible_types(op, ltp, lt, rtp, rt); 2362 return false; 2363 } 2364 return true; 2365 } 2366 2367 static bool 2368 typeok_minus(op_t op, 2369 const type_t *ltp, tspec_t lt, 2370 const type_t *rtp, tspec_t rt) 2371 { 2372 /* operands have scalar types (checked in typeok) */ 2373 if ((lt == PTR && rt != PTR && !is_integer(rt)) || 2374 (lt != PTR && rt == PTR)) { 2375 warn_incompatible_types(op, ltp, lt, rtp, rt); 2376 return false; 2377 } 2378 if (lt == PTR && rt == PTR && 2379 !types_compatible(ltp->t_subt, rtp->t_subt, true, false, NULL)) { 2380 /* illegal pointer subtraction */ 2381 error(116); 2382 } 2383 return true; 2384 } 2385 2386 static void 2387 typeok_shr(op_t op, 2388 const tnode_t *ln, tspec_t lt, 2389 const tnode_t *rn, tspec_t rt) 2390 { 2391 tspec_t olt = before_conversion(ln)->tn_type->t_tspec; 2392 tspec_t ort = before_conversion(rn)->tn_type->t_tspec; 2393 2394 /* operands have integer types (checked in typeok) */ 2395 if (pflag && !is_uinteger(olt)) { 2396 integer_constraints lc = ic_expr(ln); 2397 if (!ic_maybe_signed(ln->tn_type, &lc)) 2398 return; 2399 2400 if (ln->tn_op != CON) 2401 /* bitwise '%s' on signed value possibly nonportable */ 2402 warning(117, op_name(op)); 2403 else if (ln->u.value.u.integer < 0) 2404 /* bitwise '%s' on signed value nonportable */ 2405 warning(120, op_name(op)); 2406 } else if (allow_trad && allow_c90 && 2407 !is_uinteger(olt) && is_uinteger(ort)) { 2408 /* The left operand would become unsigned in traditional C. */ 2409 if (hflag && (ln->tn_op != CON || ln->u.value.u.integer < 0)) { 2410 /* semantics of '%s' change in C90; use ... */ 2411 warning(118, op_name(op)); 2412 } 2413 } else if (allow_trad && allow_c90 && 2414 !is_uinteger(olt) && !is_uinteger(ort) && 2415 portable_rank_cmp(lt, rt) < 0) { 2416 /* 2417 * In traditional C, the left operand would be extended 2418 * (possibly sign-extended) and then shifted. 2419 */ 2420 if (hflag && (ln->tn_op != CON || ln->u.value.u.integer < 0)) { 2421 /* semantics of '%s' change in C90; use ... */ 2422 warning(118, op_name(op)); 2423 } 2424 } 2425 } 2426 2427 static void 2428 typeok_shl(op_t op, tspec_t lt, tspec_t rt) 2429 { 2430 /* 2431 * C90 does not perform balancing for shift operations, but traditional 2432 * C does. If the width of the right operand is greater than the width 2433 * of the left operand, then in traditional C the left operand would be 2434 * extended to the width of the right operand. For SHL this may result 2435 * in different results. 2436 */ 2437 if (portable_rank_cmp(lt, rt) < 0) { 2438 /* 2439 * XXX If both operands are constant, make sure that there is 2440 * really a difference between C90 and traditional C. 2441 */ 2442 if (hflag && allow_trad && allow_c90) 2443 /* semantics of '%s' change in C90; use ... */ 2444 warning(118, op_name(op)); 2445 } 2446 } 2447 2448 static void 2449 typeok_shift(const type_t *ltp, tspec_t lt, const tnode_t *rn, tspec_t rt) 2450 { 2451 if (rn->tn_op != CON) 2452 return; 2453 2454 if (!is_uinteger(rt) && rn->u.value.u.integer < 0) 2455 /* negative shift */ 2456 warning(121); 2457 else if ((uint64_t)rn->u.value.u.integer == size_in_bits(lt)) 2458 /* shift amount %u equals bit-size of '%s' */ 2459 warning(267, (unsigned)rn->u.value.u.integer, type_name(ltp)); 2460 else if ((uint64_t)rn->u.value.u.integer > size_in_bits(lt)) { 2461 /* shift amount %llu is greater than bit-size %llu of '%s' */ 2462 warning(122, (unsigned long long)rn->u.value.u.integer, 2463 (unsigned long long)size_in_bits(lt), 2464 tspec_name(lt)); 2465 } 2466 } 2467 2468 static bool 2469 is_typeok_eq(const tnode_t *ln, tspec_t lt, const tnode_t *rn, tspec_t rt) 2470 { 2471 if (lt == PTR && is_null_pointer(rn)) 2472 return true; 2473 if (rt == PTR && is_null_pointer(ln)) 2474 return true; 2475 return false; 2476 } 2477 2478 static void 2479 warn_incompatible_pointers(op_t op, const type_t *ltp, const type_t *rtp) 2480 { 2481 lint_assert(ltp->t_tspec == PTR); 2482 lint_assert(rtp->t_tspec == PTR); 2483 2484 tspec_t lt = ltp->t_subt->t_tspec; 2485 tspec_t rt = rtp->t_subt->t_tspec; 2486 2487 if (is_struct_or_union(lt) && is_struct_or_union(rt)) { 2488 if (op == RETURN) 2489 /* illegal structure pointer combination */ 2490 warning(244); 2491 else { 2492 /* incompatible structure pointers: '%s' '%s' '%s' */ 2493 warning(245, type_name(ltp), 2494 op_name(op), type_name(rtp)); 2495 } 2496 } else { 2497 if (op == RETURN) 2498 /* illegal combination of '%s' and '%s' */ 2499 warning(184, type_name(ltp), type_name(rtp)); 2500 else { 2501 /* illegal combination of '%s' and '%s', op '%s' */ 2502 warning(124, 2503 type_name(ltp), type_name(rtp), op_name(op)); 2504 } 2505 } 2506 } 2507 2508 static void 2509 check_pointer_comparison(op_t op, const tnode_t *ln, const tnode_t *rn) 2510 { 2511 type_t *ltp = ln->tn_type, *rtp = rn->tn_type; 2512 tspec_t lst = ltp->t_subt->t_tspec, rst = rtp->t_subt->t_tspec; 2513 2514 if (lst == VOID || rst == VOID) { 2515 /* TODO: C99 behaves like C90 here. */ 2516 if (!allow_trad && !allow_c99 && 2517 (lst == FUNC || rst == FUNC)) { 2518 /* (void *)0 is already handled in typeok() */ 2519 const char *lsts, *rsts; 2520 *(lst == FUNC ? &lsts : &rsts) = "function pointer"; 2521 *(lst == VOID ? &lsts : &rsts) = "'void *'"; 2522 /* C90 or later forbid comparison of %s with %s */ 2523 warning(274, lsts, rsts); 2524 } 2525 return; 2526 } 2527 2528 if (!types_compatible(ltp->t_subt, rtp->t_subt, true, false, NULL)) { 2529 warn_incompatible_pointers(op, ltp, rtp); 2530 return; 2531 } 2532 2533 if (lst == FUNC && rst == FUNC) { 2534 /* TODO: C99 behaves like C90 here, see C99 6.5.8p2. */ 2535 if (!allow_trad && !allow_c99 && op != EQ && op != NE) 2536 /* pointers to functions can only be compared ... */ 2537 warning(125); 2538 } 2539 } 2540 2541 static bool 2542 typeok_compare(op_t op, 2543 const tnode_t *ln, const type_t *ltp, tspec_t lt, 2544 const tnode_t *rn, const type_t *rtp, tspec_t rt) 2545 { 2546 if (lt == PTR && rt == PTR) { 2547 check_pointer_comparison(op, ln, rn); 2548 return true; 2549 } 2550 2551 if (lt != PTR && rt != PTR) 2552 return true; 2553 2554 if (!is_integer(lt) && !is_integer(rt)) { 2555 warn_incompatible_types(op, ltp, lt, rtp, rt); 2556 return false; 2557 } 2558 2559 const char *lx = lt == PTR ? "pointer" : "integer"; 2560 const char *rx = rt == PTR ? "pointer" : "integer"; 2561 /* illegal combination of %s '%s' and %s '%s', op '%s' */ 2562 warning(123, lx, type_name(ltp), rx, type_name(rtp), op_name(op)); 2563 return true; 2564 } 2565 2566 static bool 2567 typeok_quest(tspec_t lt, const tnode_t *rn) 2568 { 2569 if (!is_scalar(lt)) { 2570 /* first operand of '?' must have scalar type */ 2571 error(170); 2572 return false; 2573 } 2574 lint_assert(before_conversion(rn)->tn_op == COLON); 2575 return true; 2576 } 2577 2578 static void 2579 typeok_colon_pointer(const type_t *ltp, const type_t *rtp) 2580 { 2581 type_t *lstp = ltp->t_subt; 2582 type_t *rstp = rtp->t_subt; 2583 tspec_t lst = lstp->t_tspec; 2584 tspec_t rst = rstp->t_tspec; 2585 2586 if ((lst == VOID && rst == FUNC) || (lst == FUNC && rst == VOID)) { 2587 /* (void *)0 is handled in typeok_colon */ 2588 /* TODO: C99 behaves like C90 here. */ 2589 if (!allow_trad && !allow_c99) 2590 /* conversion of %s to %s requires a cast, op %s */ 2591 warning(305, "function pointer", "'void *'", 2592 op_name(COLON)); 2593 return; 2594 } 2595 2596 if (pointer_types_are_compatible(lstp, rstp, true)) 2597 return; 2598 if (!types_compatible(lstp, rstp, true, false, NULL)) 2599 warn_incompatible_pointers(COLON, ltp, rtp); 2600 } 2601 2602 static bool 2603 typeok_colon(const tnode_t *ln, const type_t *ltp, tspec_t lt, 2604 const tnode_t *rn, const type_t *rtp, tspec_t rt) 2605 { 2606 2607 if (is_arithmetic(lt) && is_arithmetic(rt)) 2608 return true; 2609 if (lt == BOOL && rt == BOOL) 2610 return true; 2611 2612 if (lt == STRUCT && rt == STRUCT && ltp->u.sou == rtp->u.sou) 2613 return true; 2614 if (lt == UNION && rt == UNION && ltp->u.sou == rtp->u.sou) 2615 return true; 2616 2617 if (lt == PTR && is_null_pointer(rn)) 2618 return true; 2619 if (rt == PTR && is_null_pointer(ln)) 2620 return true; 2621 2622 if ((lt == PTR && is_integer(rt)) || (is_integer(lt) && rt == PTR)) { 2623 const char *lx = lt == PTR ? "pointer" : "integer"; 2624 const char *rx = rt == PTR ? "pointer" : "integer"; 2625 /* illegal combination of %s '%s' and %s '%s', op '%s' */ 2626 warning(123, lx, type_name(ltp), 2627 rx, type_name(rtp), op_name(COLON)); 2628 return true; 2629 } 2630 2631 if (lt == VOID || rt == VOID) { 2632 if (lt != VOID || rt != VOID) 2633 /* incompatible types '%s' and '%s' in conditional */ 2634 warning(126, type_name(ltp), type_name(rtp)); 2635 return true; 2636 } 2637 2638 if (lt == PTR && rt == PTR) { 2639 typeok_colon_pointer(ltp, rtp); 2640 return true; 2641 } 2642 2643 /* incompatible types '%s' and '%s' in conditional */ 2644 error(126, type_name(ltp), type_name(rtp)); 2645 return false; 2646 } 2647 2648 static bool 2649 has_constant_member(const type_t *tp) 2650 { 2651 lint_assert(is_struct_or_union(tp->t_tspec)); 2652 2653 for (sym_t *m = tp->u.sou->sou_first_member; 2654 m != NULL; m = m->s_next) { 2655 const type_t *mtp = m->s_type; 2656 if (mtp->t_const) 2657 return true; 2658 if (is_struct_or_union(mtp->t_tspec) && 2659 has_constant_member(mtp)) 2660 return true; 2661 } 2662 return false; 2663 } 2664 2665 static bool 2666 typeok_assign(op_t op, const tnode_t *ln, const type_t *ltp, tspec_t lt) 2667 { 2668 if (op == RETURN || op == INIT || op == FARG) 2669 return true; 2670 2671 if (!ln->tn_lvalue) { 2672 if (ln->tn_op == CVT && ln->tn_cast && 2673 ln->u.ops.left->tn_op == LOAD) 2674 /* a cast does not yield an lvalue */ 2675 error(163); 2676 /* %soperand of '%s' must be lvalue */ 2677 error(114, "left ", op_name(op)); 2678 return false; 2679 } else if (ltp->t_const 2680 || (is_struct_or_union(lt) && has_constant_member(ltp))) { 2681 if (allow_c90) 2682 /* %soperand of '%s' must be modifiable lvalue */ 2683 warning(115, "left ", op_name(op)); 2684 } 2685 return true; 2686 } 2687 2688 static bool 2689 typeok_scalar(op_t op, const mod_t *mp, 2690 const type_t *ltp, tspec_t lt, 2691 const type_t *rtp, tspec_t rt) 2692 { 2693 if (mp->m_takes_bool && lt == BOOL && rt == BOOL) 2694 return true; 2695 if (mp->m_requires_integer) { 2696 if (!is_integer(lt) || (mp->m_binary && !is_integer(rt))) { 2697 warn_incompatible_types(op, ltp, lt, rtp, rt); 2698 return false; 2699 } 2700 } else if (mp->m_requires_integer_or_complex) { 2701 if ((!is_integer(lt) && !is_complex(lt)) || 2702 (mp->m_binary && (!is_integer(rt) && !is_complex(rt)))) { 2703 warn_incompatible_types(op, ltp, lt, rtp, rt); 2704 return false; 2705 } 2706 } else if (mp->m_requires_scalar) { 2707 if (!is_scalar(lt) || (mp->m_binary && !is_scalar(rt))) { 2708 warn_incompatible_types(op, ltp, lt, rtp, rt); 2709 return false; 2710 } 2711 } else if (mp->m_requires_arith) { 2712 if (!is_arithmetic(lt) || 2713 (mp->m_binary && !is_arithmetic(rt))) { 2714 warn_incompatible_types(op, ltp, lt, rtp, rt); 2715 return false; 2716 } 2717 } 2718 return true; 2719 } 2720 2721 static void 2722 check_assign_void_pointer(op_t op, int arg, 2723 tspec_t lt, tspec_t lst, 2724 tspec_t rt, tspec_t rst) 2725 { 2726 2727 if (!(lt == PTR && rt == PTR && (lst == VOID || rst == VOID))) 2728 return; 2729 /* two pointers, at least one pointer to void */ 2730 2731 /* TODO: C99 behaves like C90 here. */ 2732 if (!(!allow_trad && !allow_c99 && (lst == FUNC || rst == FUNC))) 2733 return; 2734 /* comb. of ptr to func and ptr to void */ 2735 2736 const char *lts, *rts; 2737 *(lst == FUNC ? <s : &rts) = "function pointer"; 2738 *(lst == VOID ? <s : &rts) = "'void *'"; 2739 2740 switch (op) { 2741 case INIT: 2742 case RETURN: 2743 /* conversion of %s to %s requires a cast */ 2744 warning(303, rts, lts); 2745 break; 2746 case FARG: 2747 /* conversion of %s to %s requires a cast, arg #%d */ 2748 warning(304, rts, lts, arg); 2749 break; 2750 default: 2751 /* conversion of %s to %s requires a cast, op %s */ 2752 warning(305, rts, lts, op_name(op)); 2753 break; 2754 } 2755 } 2756 2757 static bool 2758 is_direct_function_call(const tnode_t *tn, const char **out_name) 2759 { 2760 2761 if (tn->tn_op == CALL 2762 && tn->u.call->func->tn_op == ADDR 2763 && tn->u.call->func->u.ops.left->tn_op == NAME) { 2764 *out_name = tn->u.call->func->u.ops.left->u.sym->s_name; 2765 return true; 2766 } 2767 return false; 2768 } 2769 2770 static bool 2771 is_unconst_function(const char *name) 2772 { 2773 2774 return strcmp(name, "memchr") == 0 || 2775 strcmp(name, "strchr") == 0 || 2776 strcmp(name, "strpbrk") == 0 || 2777 strcmp(name, "strrchr") == 0 || 2778 strcmp(name, "strstr") == 0; 2779 } 2780 2781 static bool 2782 is_const_char_pointer(const tnode_t *tn) 2783 { 2784 /* 2785 * For traditional reasons, C99 6.4.5p5 defines that string literals 2786 * have type 'char[]'. They are often implicitly converted to 'char 2787 * *', for example when they are passed as function arguments. 2788 * 2789 * C99 6.4.5p6 further defines that modifying a string that is 2790 * constructed from a string literal invokes undefined behavior. 2791 * 2792 * Out of these reasons, string literals are treated as 'effectively 2793 * const' here. 2794 */ 2795 if (tn->tn_op == CVT && 2796 tn->u.ops.left->tn_op == ADDR && 2797 tn->u.ops.left->u.ops.left->tn_op == STRING) 2798 return true; 2799 2800 const type_t *tp = before_conversion(tn)->tn_type; 2801 return tp->t_tspec == PTR && 2802 tp->t_subt->t_tspec == CHAR && 2803 tp->t_subt->t_const; 2804 } 2805 2806 static bool 2807 is_const_pointer(const tnode_t *tn) 2808 { 2809 const type_t *tp = before_conversion(tn)->tn_type; 2810 return tp->t_tspec == PTR && tp->t_subt->t_const; 2811 } 2812 2813 static void 2814 check_unconst_function(const type_t *lstp, const tnode_t *rn) 2815 { 2816 const char *function_name; 2817 2818 if (lstp->t_tspec == CHAR && !lstp->t_const && 2819 is_direct_function_call(rn, &function_name) && 2820 is_unconst_function(function_name) && 2821 rn->u.call->args_len >= 1 && 2822 is_const_char_pointer(rn->u.call->args[0])) { 2823 /* call to '%s' effectively discards 'const' from argument */ 2824 warning(346, function_name); 2825 } 2826 2827 if (!lstp->t_const && 2828 is_direct_function_call(rn, &function_name) && 2829 strcmp(function_name, "bsearch") == 0 && 2830 rn->u.call->args_len >= 2 && 2831 is_const_pointer(rn->u.call->args[1])) { 2832 /* call to '%s' effectively discards 'const' from argument */ 2833 warning(346, function_name); 2834 } 2835 } 2836 2837 static bool 2838 check_assign_void_pointer_compat(op_t op, int arg, 2839 tspec_t lt, 2840 const type_t *lstp, tspec_t lst, 2841 const tnode_t *rn, 2842 const type_t *rtp, tspec_t rt, 2843 const type_t *rstp, tspec_t rst) 2844 { 2845 if (!(lt == PTR && rt == PTR && (lst == VOID || rst == VOID || 2846 types_compatible(lstp, rstp, 2847 true, false, NULL)))) 2848 return false; 2849 2850 /* compatible pointer types (qualifiers ignored) */ 2851 char qualifiers[32]; 2852 snprintf(qualifiers, sizeof(qualifiers), "%s%s", 2853 !lstp->t_const && rstp->t_const ? " const" : "", 2854 !lstp->t_volatile && rstp->t_volatile ? " volatile" : ""); 2855 if (allow_c90 && qualifiers[0] != '\0') { 2856 switch (op) { 2857 case INIT: 2858 case RETURN: 2859 /* '%s' discards '%s' from '%s' */ 2860 warning(182, op_name(op), 2861 qualifiers + 1, type_name(rtp)); 2862 break; 2863 case FARG: 2864 /* passing '%s' to argument %d discards '%s' */ 2865 warning(383, type_name(rtp), arg, qualifiers + 1); 2866 break; 2867 default: 2868 /* operator '%s' discards '%s' from '%s' */ 2869 warning(128, op_name(op), 2870 qualifiers + 1, type_name(rtp)); 2871 break; 2872 } 2873 } 2874 2875 if (allow_c90) 2876 check_unconst_function(lstp, rn); 2877 2878 return true; 2879 } 2880 2881 static bool 2882 check_assign_pointer_integer(op_t op, int arg, 2883 const type_t *ltp, tspec_t lt, 2884 const type_t *rtp, tspec_t rt) 2885 { 2886 2887 if (!((lt == PTR && is_integer(rt)) || (is_integer(lt) && rt == PTR))) 2888 return false; 2889 2890 const char *lx = lt == PTR ? "pointer" : "integer"; 2891 const char *rx = rt == PTR ? "pointer" : "integer"; 2892 2893 switch (op) { 2894 case INIT: 2895 case RETURN: 2896 /* illegal combination of %s '%s' and %s '%s' */ 2897 warning(183, lx, type_name(ltp), rx, type_name(rtp)); 2898 break; 2899 case FARG: 2900 /* illegal combination of %s '%s' and %s '%s', arg #%d */ 2901 warning(154, 2902 lx, type_name(ltp), rx, type_name(rtp), arg); 2903 break; 2904 default: 2905 /* illegal combination of %s '%s' and %s '%s', op '%s' */ 2906 warning(123, 2907 lx, type_name(ltp), rx, type_name(rtp), op_name(op)); 2908 break; 2909 } 2910 return true; 2911 } 2912 2913 static bool 2914 check_assign_pointer(op_t op, int arg, 2915 const type_t *ltp, tspec_t lt, 2916 const type_t *rtp, tspec_t rt) 2917 { 2918 if (!(lt == PTR && rt == PTR)) 2919 return false; 2920 2921 if (op == FARG) 2922 /* converting '%s' to incompatible '%s' for ... */ 2923 warning(153, type_name(rtp), type_name(ltp), arg); 2924 else 2925 warn_incompatible_pointers(op, ltp, rtp); 2926 return true; 2927 } 2928 2929 static void 2930 warn_assign(op_t op, int arg, 2931 const type_t *ltp, tspec_t lt, 2932 const type_t *rtp, tspec_t rt) 2933 { 2934 switch (op) { 2935 case INIT: 2936 /* cannot initialize '%s' from '%s' */ 2937 error(185, type_name(ltp), type_name(rtp)); 2938 break; 2939 case RETURN: 2940 /* function has return type '%s' but returns '%s' */ 2941 error(211, type_name(ltp), type_name(rtp)); 2942 break; 2943 case FARG: 2944 /* passing '%s' to incompatible '%s', arg #%d */ 2945 warning(155, type_name(rtp), type_name(ltp), arg); 2946 break; 2947 default: 2948 warn_incompatible_types(op, ltp, lt, rtp, rt); 2949 break; 2950 } 2951 } 2952 2953 /* 2954 * Checks type compatibility for ASSIGN, INIT, FARG and RETURN 2955 * and prints warnings/errors if necessary. 2956 * Returns whether the types are (almost) compatible. 2957 */ 2958 static bool 2959 check_assign_types_compatible(op_t op, int arg, 2960 const tnode_t *ln, const tnode_t *rn) 2961 { 2962 tspec_t lt, rt, lst = NO_TSPEC, rst = NO_TSPEC; 2963 type_t *ltp, *rtp, *lstp = NULL, *rstp = NULL; 2964 2965 if ((lt = (ltp = ln->tn_type)->t_tspec) == PTR) 2966 lst = (lstp = ltp->t_subt)->t_tspec; 2967 if ((rt = (rtp = rn->tn_type)->t_tspec) == PTR) 2968 rst = (rstp = rtp->t_subt)->t_tspec; 2969 2970 if (lt == BOOL && is_scalar(rt)) /* C99 6.3.1.2 */ 2971 return true; 2972 2973 if (is_arithmetic(lt) && (is_arithmetic(rt) || rt == BOOL)) 2974 return true; 2975 2976 if (is_struct_or_union(lt) && is_struct_or_union(rt)) 2977 return ltp->u.sou == rtp->u.sou; 2978 2979 if (lt == PTR && is_null_pointer(rn)) { 2980 if (is_integer(rn->tn_type->t_tspec)) 2981 /* implicit conversion from integer 0 to pointer ... */ 2982 query_message(15, type_name(ltp)); 2983 return true; 2984 } 2985 2986 check_assign_void_pointer(op, arg, lt, lst, rt, rst); 2987 2988 if (check_assign_void_pointer_compat(op, arg, 2989 lt, lstp, lst, rn, rtp, rt, rstp, rst)) 2990 return true; 2991 2992 if (check_assign_pointer_integer(op, arg, ltp, lt, rtp, rt)) 2993 return true; 2994 2995 if (check_assign_pointer(op, arg, ltp, lt, rtp, rt)) 2996 return true; 2997 2998 warn_assign(op, arg, ltp, lt, rtp, rt); 2999 return false; 3000 } 3001 3002 static bool 3003 has_side_effect(const tnode_t *tn) /* NOLINT(misc-no-recursion) */ 3004 { 3005 op_t op = tn->tn_op; 3006 3007 if (modtab[op].m_has_side_effect) 3008 return true; 3009 3010 if (op == CVT && tn->tn_type->t_tspec == VOID) 3011 return has_side_effect(tn->u.ops.left); 3012 3013 /* XXX: Why not has_side_effect(tn->u.ops.left) as well? */ 3014 if (op == LOGAND || op == LOGOR) 3015 return has_side_effect(tn->u.ops.right); 3016 3017 /* XXX: Why not has_side_effect(tn->u.ops.left) as well? */ 3018 if (op == QUEST) 3019 return has_side_effect(tn->u.ops.right); 3020 3021 if (op == COLON || op == COMMA) { 3022 return has_side_effect(tn->u.ops.left) || 3023 has_side_effect(tn->u.ops.right); 3024 } 3025 3026 return false; 3027 } 3028 3029 static bool 3030 is_void_cast(const tnode_t *tn) 3031 { 3032 3033 return tn->tn_op == CVT && tn->tn_cast && 3034 tn->tn_type->t_tspec == VOID; 3035 } 3036 3037 static bool 3038 is_local_symbol(const tnode_t *tn) 3039 { 3040 3041 return tn->tn_op == LOAD && 3042 tn->u.ops.left->tn_op == NAME && 3043 tn->u.ops.left->u.sym->s_scl == AUTO; 3044 } 3045 3046 static bool 3047 is_int_constant_zero(const tnode_t *tn) 3048 { 3049 3050 return tn->tn_op == CON && 3051 tn->tn_type->t_tspec == INT && 3052 tn->u.value.u.integer == 0; 3053 } 3054 3055 static void 3056 check_null_effect(const tnode_t *tn) 3057 { 3058 3059 if (hflag && 3060 !has_side_effect(tn) && 3061 !(is_void_cast(tn) && is_local_symbol(tn->u.ops.left)) && 3062 !(is_void_cast(tn) && is_int_constant_zero(tn->u.ops.left))) { 3063 /* expression has null effect */ 3064 warning(129); 3065 } 3066 } 3067 3068 /* 3069 * Check the types for specific operators and type combinations. 3070 * 3071 * At this point, the operands already conform to the type requirements of 3072 * the operator, such as being integer, floating or scalar. 3073 */ 3074 static bool 3075 typeok_op(op_t op, int arg, 3076 const tnode_t *ln, const type_t *ltp, tspec_t lt, 3077 const tnode_t *rn, const type_t *rtp, tspec_t rt) 3078 { 3079 switch (op) { 3080 case ARROW: 3081 return typeok_arrow(lt); 3082 case POINT: 3083 return typeok_point(ln, ltp, lt); 3084 case INCBEF: 3085 case DECBEF: 3086 case INCAFT: 3087 case DECAFT: 3088 return typeok_incdec(op, ln, ltp); 3089 case INDIR: 3090 return typeok_indir(ltp, lt); 3091 case ADDR: 3092 return typeok_address(op, ln, ltp, lt); 3093 case PLUS: 3094 return typeok_plus(op, ltp, lt, rtp, rt); 3095 case MINUS: 3096 return typeok_minus(op, ltp, lt, rtp, rt); 3097 case SHL: 3098 typeok_shl(op, lt, rt); 3099 goto shift; 3100 case SHR: 3101 typeok_shr(op, ln, lt, rn, rt); 3102 shift: 3103 typeok_shift(ltp, lt, rn, rt); 3104 break; 3105 case LT: 3106 case LE: 3107 case GT: 3108 case GE: 3109 compare: 3110 return typeok_compare(op, ln, ltp, lt, rn, rtp, rt); 3111 case EQ: 3112 case NE: 3113 if (is_typeok_eq(ln, lt, rn, rt)) 3114 break; 3115 goto compare; 3116 case QUEST: 3117 return typeok_quest(lt, rn); 3118 case COLON: 3119 return typeok_colon(ln, ltp, lt, rn, rtp, rt); 3120 case ASSIGN: 3121 case INIT: 3122 case FARG: 3123 case RETURN: 3124 if (!check_assign_types_compatible(op, arg, ln, rn)) 3125 return false; 3126 goto assign; 3127 case MULASS: 3128 case DIVASS: 3129 case MODASS: 3130 goto assign; 3131 case ADDASS: 3132 case SUBASS: 3133 if ((lt == PTR && !is_integer(rt)) || rt == PTR) { 3134 warn_incompatible_types(op, ltp, lt, rtp, rt); 3135 return false; 3136 } 3137 goto assign; 3138 case SHLASS: 3139 goto assign; 3140 case SHRASS: 3141 if (pflag && !is_uinteger(lt) && 3142 !(!allow_c90 && is_uinteger(rt))) { 3143 /* bitwise '%s' on signed value possibly nonportable */ 3144 warning(117, op_name(op)); 3145 } 3146 goto assign; 3147 case ANDASS: 3148 case XORASS: 3149 case ORASS: 3150 assign: 3151 return typeok_assign(op, ln, ltp, lt); 3152 case COMMA: 3153 if (!modtab[ln->tn_op].m_has_side_effect) 3154 check_null_effect(ln); 3155 break; 3156 default: 3157 break; 3158 } 3159 return true; 3160 } 3161 3162 static void 3163 check_bad_enum_operation(op_t op, const tnode_t *ln, const tnode_t *rn) 3164 { 3165 3166 if (!eflag) 3167 return; 3168 3169 /* Allow enum in array indices. */ 3170 if (op == PLUS && 3171 ((ln->tn_type->t_is_enum && rn->tn_type->t_tspec == PTR) || 3172 (rn->tn_type->t_is_enum && ln->tn_type->t_tspec == PTR))) { 3173 return; 3174 } 3175 3176 /* dubious operation '%s' on enum */ 3177 warning(241, op_name(op)); 3178 } 3179 3180 static void 3181 check_enum_type_mismatch(op_t op, int arg, const tnode_t *ln, const tnode_t *rn) 3182 { 3183 const mod_t *mp = &modtab[op]; 3184 3185 if (ln->tn_type->u.enumer != rn->tn_type->u.enumer) { 3186 switch (op) { 3187 case INIT: 3188 /* enum type mismatch between '%s' and '%s' in ... */ 3189 warning(210, 3190 type_name(ln->tn_type), type_name(rn->tn_type)); 3191 break; 3192 case FARG: 3193 /* function expects '%s', passing '%s' for arg #%d */ 3194 warning(156, 3195 type_name(ln->tn_type), type_name(rn->tn_type), 3196 arg); 3197 break; 3198 case RETURN: 3199 /* function has return type '%s' but returns '%s' */ 3200 warning(211, 3201 type_name(ln->tn_type), type_name(rn->tn_type)); 3202 break; 3203 default: 3204 /* enum type mismatch: '%s' '%s' '%s' */ 3205 warning(130, type_name(ln->tn_type), op_name(op), 3206 type_name(rn->tn_type)); 3207 break; 3208 } 3209 } else if (Pflag && eflag && mp->m_comparison && op != EQ && op != NE) 3210 /* operator '%s' assumes that '%s' is ordered */ 3211 warning(243, op_name(op), type_name(ln->tn_type)); 3212 } 3213 3214 static void 3215 check_enum_int_mismatch(op_t op, int arg, const tnode_t *ln, const tnode_t *rn) 3216 { 3217 3218 if (!eflag) 3219 return; 3220 3221 switch (op) { 3222 case INIT: 3223 /* 3224 * Initialization with 0 is allowed. Otherwise, all implicit 3225 * initializations would need to be warned upon as well. 3226 */ 3227 if (!rn->tn_type->t_is_enum && rn->tn_op == CON && 3228 is_integer(rn->tn_type->t_tspec) && 3229 rn->u.value.u.integer == 0) { 3230 return; 3231 } 3232 /* initialization of '%s' with '%s' */ 3233 warning(277, type_name(ln->tn_type), type_name(rn->tn_type)); 3234 break; 3235 case FARG: 3236 /* combination of '%s' and '%s', arg #%d */ 3237 warning(278, 3238 type_name(ln->tn_type), type_name(rn->tn_type), arg); 3239 break; 3240 case RETURN: 3241 /* combination of '%s' and '%s' in return */ 3242 warning(279, type_name(ln->tn_type), type_name(rn->tn_type)); 3243 break; 3244 default: 3245 /* combination of '%s' and '%s', op '%s' */ 3246 warning(242, type_name(ln->tn_type), type_name(rn->tn_type), 3247 op_name(op)); 3248 break; 3249 } 3250 } 3251 3252 static void 3253 typeok_enum(op_t op, const mod_t *mp, int arg, 3254 const tnode_t *ln, const type_t *ltp, 3255 const tnode_t *rn, const type_t *rtp) 3256 { 3257 if (mp->m_bad_on_enum && 3258 (ltp->t_is_enum || (mp->m_binary && rtp->t_is_enum))) { 3259 check_bad_enum_operation(op, ln, rn); 3260 } else if (mp->m_valid_on_enum && 3261 (ltp->t_is_enum && rtp != NULL && rtp->t_is_enum)) { 3262 check_enum_type_mismatch(op, arg, ln, rn); 3263 } else if (mp->m_valid_on_enum && 3264 (ltp->t_is_enum || (rtp != NULL && rtp->t_is_enum))) { 3265 check_enum_int_mismatch(op, arg, ln, rn); 3266 } 3267 } 3268 3269 /* Perform most type checks. Return whether the types are ok. */ 3270 bool 3271 typeok(op_t op, int arg, const tnode_t *ln, const tnode_t *rn) 3272 { 3273 3274 const mod_t *mp = &modtab[op]; 3275 3276 type_t *ltp = ln->tn_type; 3277 tspec_t lt = ltp->t_tspec; 3278 3279 type_t *rtp = mp->m_binary ? rn->tn_type : NULL; 3280 tspec_t rt = mp->m_binary ? rtp->t_tspec : NO_TSPEC; 3281 3282 if (Tflag && !typeok_scalar_strict_bool(op, mp, arg, ln, rn)) 3283 return false; 3284 if (!typeok_scalar(op, mp, ltp, lt, rtp, rt)) 3285 return false; 3286 3287 if (!typeok_op(op, arg, ln, ltp, lt, rn, rtp, rt)) 3288 return false; 3289 3290 typeok_enum(op, mp, arg, ln, ltp, rn, rtp); 3291 return true; 3292 } 3293 3294 /* In traditional C, keep unsigned and promote FLOAT to DOUBLE. */ 3295 static tspec_t 3296 promote_trad(tspec_t t) 3297 { 3298 3299 if (t == UCHAR || t == USHORT) 3300 return UINT; 3301 if (t == CHAR || t == SCHAR || t == SHORT) 3302 return INT; 3303 if (t == FLOAT) 3304 return DOUBLE; 3305 if (t == ENUM) 3306 return INT; 3307 return t; 3308 } 3309 3310 /* 3311 * C99 6.3.1.1p2 requires for types with lower rank than int that "If an int 3312 * can represent all the values of the original type, the value is converted 3313 * to an int; otherwise it is converted to an unsigned int", and that "All 3314 * other types are unchanged by the integer promotions". 3315 */ 3316 static tspec_t 3317 promote_c90(const tnode_t *tn, tspec_t t, bool farg) 3318 { 3319 if (tn->tn_type->t_bitfield) { 3320 unsigned int width = tn->tn_type->t_bit_field_width; 3321 unsigned int int_width = size_in_bits(INT); 3322 // XXX: What about _Bool bit-fields, since C99? 3323 if (width < int_width) 3324 return INT; 3325 if (width == int_width) 3326 return is_uinteger(t) ? UINT : INT; 3327 return t; 3328 } 3329 3330 if (t == CHAR || t == SCHAR) 3331 return INT; 3332 if (t == UCHAR) 3333 return size_in_bits(CHAR) < size_in_bits(INT) ? INT : UINT; 3334 if (t == SHORT) 3335 return INT; 3336 if (t == USHORT) 3337 return size_in_bits(SHORT) < size_in_bits(INT) ? INT : UINT; 3338 if (t == ENUM) 3339 return INT; 3340 if (farg && t == FLOAT) 3341 return DOUBLE; 3342 return t; 3343 } 3344 3345 /* 3346 * Performs the "integer promotions" (C99 6.3.1.1p2), which convert small 3347 * integer types to either int or unsigned int. 3348 * 3349 * If allow_c90 is unset or the operand is a function argument with no type 3350 * information (no prototype or variable # of args), converts float to double. 3351 */ 3352 tnode_t * 3353 promote(op_t op, bool farg, tnode_t *tn) 3354 { 3355 3356 const type_t *otp = tn->tn_type; 3357 tspec_t ot = otp->t_tspec; 3358 if (!is_arithmetic(ot)) 3359 return tn; 3360 3361 tspec_t nt = allow_c90 ? promote_c90(tn, ot, farg) : promote_trad(ot); 3362 if (nt == ot) 3363 return tn; 3364 3365 type_t *ntp = expr_dup_type(gettyp(nt)); 3366 ntp->t_tspec = nt; 3367 ntp->t_is_enum = otp->t_is_enum; 3368 if (ntp->t_is_enum) 3369 ntp->u.enumer = otp->u.enumer; 3370 ntp->t_bitfield = otp->t_bitfield; 3371 if (ntp->t_bitfield) { 3372 ntp->t_bit_field_width = otp->t_bit_field_width; 3373 ntp->t_bit_field_offset = otp->t_bit_field_offset; 3374 } 3375 if (ntp->t_bitfield && is_uinteger(ot) && !is_uinteger(nt)) 3376 ntp->t_bit_field_width++; 3377 return convert(op, 0, ntp, tn); 3378 } 3379 3380 static void 3381 check_lossy_floating_to_integer_conversion( 3382 op_t op, int arg, const type_t *tp, const tnode_t *tn) 3383 { 3384 long double x = tn->u.value.u.floating; 3385 integer_constraints ic = ic_any(tp); 3386 if (is_uinteger(tp->t_tspec) 3387 ? x >= ic.umin && x <= ic.umax && x == (uint64_t)x 3388 : x >= ic.smin && x <= ic.smax && x == (int64_t)x) 3389 return; 3390 if (op == FARG) 3391 /* lossy conversion of %Lg to '%s', arg #%d */ 3392 warning(380, x, type_name(tp), arg); 3393 else 3394 /* lossy conversion of %Lg to '%s' */ 3395 warning(381, x, type_name(tp)); 3396 } 3397 3398 static void 3399 convert_integer_from_floating( 3400 op_t op, int arg, const type_t *tp, const tnode_t *tn) 3401 { 3402 3403 if (op == CVT) 3404 /* cast from floating point '%s' to integer '%s' */ 3405 query_message(2, type_name(tn->tn_type), type_name(tp)); 3406 else 3407 /* implicit conversion from floating point '%s' to ... */ 3408 query_message(1, type_name(tn->tn_type), type_name(tp)); 3409 if (tn->tn_op == CON) 3410 check_lossy_floating_to_integer_conversion(op, arg, tp, tn); 3411 } 3412 3413 static bool 3414 should_warn_about_prototype_conversion(tspec_t nt, 3415 tspec_t ot, const tnode_t *ptn) 3416 { 3417 3418 if (nt == ot) 3419 return false; 3420 3421 if (nt == ENUM && ot == INT) 3422 return false; 3423 3424 if (is_floating(nt) != is_floating(ot) || 3425 portable_rank_cmp(nt, ot) != 0) { 3426 /* representation and/or width change */ 3427 if (!is_integer(ot)) 3428 return true; 3429 /* 3430 * XXX: Investigate whether this rule makes sense; see 3431 * tests/usr.bin/xlint/lint1/platform_long.c. 3432 */ 3433 return portable_rank_cmp(ot, INT) > 0; 3434 } 3435 3436 if (!hflag) 3437 return false; 3438 3439 /* 3440 * If the types differ only in sign and the argument has the same 3441 * representation in both types, print no warning. 3442 */ 3443 if (ptn->tn_op == CON && is_integer(nt) && 3444 signed_type(nt) == signed_type(ot) && 3445 !msb(ptn->u.value.u.integer, ot)) 3446 return false; 3447 3448 return true; 3449 } 3450 3451 /* 3452 * Warn if a prototype causes a type conversion that is different from what 3453 * would happen to the same argument in the absence of a prototype. This 3454 * check is intended for code that needs to stay compatible with pre-C90 C. 3455 * 3456 * Errors/warnings about illegal type combinations are already printed 3457 * in check_assign_types_compatible(). 3458 */ 3459 static void 3460 check_prototype_conversion(int arg, tspec_t nt, tspec_t ot, type_t *tp, 3461 tnode_t *tn) 3462 { 3463 3464 if (!is_arithmetic(nt) || !is_arithmetic(ot)) 3465 return; 3466 3467 /* 3468 * If the type of the formal parameter is char/short, a warning would 3469 * be useless, because functions declared the old style can't expect 3470 * char/short arguments. 3471 */ 3472 if (nt == CHAR || nt == SCHAR || nt == UCHAR || 3473 nt == SHORT || nt == USHORT) 3474 return; 3475 3476 tnode_t *ptn = promote(NOOP, true, tn); 3477 ot = ptn->tn_type->t_tspec; 3478 3479 if (should_warn_about_prototype_conversion(nt, ot, ptn)) { 3480 /* argument %d is converted from '%s' to '%s' ... */ 3481 warning(259, arg, type_name(tn->tn_type), type_name(tp)); 3482 } 3483 } 3484 3485 /* 3486 * When converting a large integer type to a small integer type, in some 3487 * cases the value of the actual expression is further restricted than the 3488 * type bounds, such as in (expr & 0xFF) or (expr % 100) or (expr >> 24). 3489 */ 3490 static bool 3491 can_represent(const type_t *tp, const tnode_t *tn) 3492 { 3493 uint64_t nmask = value_bits(width_in_bits(tp)); 3494 if (!is_uinteger(tp->t_tspec)) 3495 nmask >>= 1; 3496 3497 integer_constraints c = ic_expr(tn); 3498 if ((~c.bclr & ~nmask) == 0) 3499 return true; 3500 3501 integer_constraints tpc = ic_any(tp); 3502 if (is_uinteger(tp->t_tspec) 3503 ? tpc.umin <= c.umin && tpc.umax >= c.umax 3504 : tpc.smin <= c.smin && tpc.smax >= c.smax) 3505 return true; 3506 3507 debug_enter(); 3508 debug_step("type '%s' cannot represent:", type_name(tp)); 3509 debug_node(tn); 3510 debug_leave(); 3511 return false; 3512 } 3513 3514 static bool 3515 should_warn_about_integer_conversion(const type_t *ntp, tspec_t nt, 3516 const tnode_t *otn, tspec_t ot) 3517 { 3518 3519 // XXX: The portable_rank_cmp aims at portable mode, independent of the 3520 // current platform, while can_represent acts on the actual type sizes 3521 // from the current platform. This mix is inconsistent, but anything 3522 // else would make the exact conditions too complicated to grasp. 3523 if (aflag > 0 && portable_rank_cmp(nt, ot) < 0) { 3524 if (ot == LONG || ot == ULONG 3525 || ot == LLONG || ot == ULLONG 3526 #ifdef INT128_SIZE 3527 || ot == INT128 || ot == UINT128 3528 #endif 3529 || aflag > 1) 3530 return !can_represent(ntp, otn); 3531 } 3532 return false; 3533 } 3534 3535 static void 3536 convert_integer_from_integer(op_t op, int arg, tspec_t nt, tspec_t ot, 3537 type_t *tp, tnode_t *tn) 3538 { 3539 3540 if (tn->tn_op == CON) 3541 return; 3542 3543 if (op == CVT) 3544 return; 3545 3546 if (Pflag && pflag && aflag > 0 && 3547 portable_rank_cmp(nt, ot) > 0 && 3548 is_uinteger(nt) != is_uinteger(ot)) { 3549 if (op == FARG) 3550 /* conversion to '%s' may sign-extend ... */ 3551 warning(297, type_name(tp), arg); 3552 else 3553 /* conversion to '%s' may sign-extend ... */ 3554 warning(131, type_name(tp)); 3555 } 3556 3557 if (Pflag && portable_rank_cmp(nt, ot) > 0 && 3558 (tn->tn_op == PLUS || tn->tn_op == MINUS || tn->tn_op == MULT || 3559 tn->tn_op == SHL)) { 3560 /* suggest cast from '%s' to '%s' on op '%s' to ... */ 3561 warning(324, type_name(gettyp(ot)), type_name(tp), 3562 op_name(tn->tn_op)); 3563 } 3564 3565 if (should_warn_about_integer_conversion(tp, nt, tn, ot)) { 3566 if (op == FARG) { 3567 /* conversion from '%s' to '%s' may lose ... */ 3568 warning(298, 3569 type_name(tn->tn_type), type_name(tp), arg); 3570 } else { 3571 /* conversion from '%s' to '%s' may lose accuracy */ 3572 warning(132, 3573 type_name(tn->tn_type), type_name(tp)); 3574 } 3575 } 3576 3577 if (is_uinteger(nt) != is_uinteger(ot)) 3578 /* implicit conversion changes sign from '%s' to '%s' */ 3579 query_message(3, type_name(tn->tn_type), type_name(tp)); 3580 } 3581 3582 static void 3583 convert_integer_from_pointer(op_t op, tspec_t nt, type_t *tp, tnode_t *tn) 3584 { 3585 3586 if (tn->tn_op == CON) 3587 return; 3588 if (op != CVT) 3589 return; /* We already got an error. */ 3590 if (portable_rank_cmp(nt, PTR) >= 0) 3591 return; 3592 3593 if (pflag && size_in_bits(nt) >= size_in_bits(PTR)) { 3594 /* conversion of pointer to '%s' may lose bits */ 3595 warning(134, type_name(tp)); 3596 } else { 3597 /* conversion of pointer to '%s' loses bits */ 3598 warning(133, type_name(tp)); 3599 } 3600 } 3601 3602 static bool 3603 struct_starts_with(const type_t *struct_tp, const type_t *member_tp) 3604 { 3605 3606 return struct_tp->u.sou->sou_first_member != NULL && 3607 types_compatible(struct_tp->u.sou->sou_first_member->s_type, 3608 member_tp, true, false, NULL); 3609 } 3610 3611 static bool 3612 is_byte_array(const type_t *tp) 3613 { 3614 3615 return tp->t_tspec == ARRAY && 3616 (tp->t_subt->t_tspec == CHAR || tp->t_subt->t_tspec == UCHAR); 3617 } 3618 3619 static bool 3620 union_contains(const type_t *utp, const type_t *mtp) 3621 { 3622 for (const sym_t *mem = utp->u.sou->sou_first_member; 3623 mem != NULL; mem = mem->s_next) { 3624 if (types_compatible(mem->s_type, mtp, true, false, NULL)) 3625 return true; 3626 } 3627 return false; 3628 } 3629 3630 static bool 3631 should_warn_about_pointer_cast(const type_t *nstp, tspec_t nst, 3632 const type_t *ostp, tspec_t ost) 3633 { 3634 3635 while (nst == ARRAY) 3636 nstp = nstp->t_subt, nst = nstp->t_tspec; 3637 while (ost == ARRAY) 3638 ostp = ostp->t_subt, ost = ostp->t_tspec; 3639 3640 if (nst == STRUCT && ost == STRUCT && 3641 (struct_starts_with(nstp, ostp) || 3642 struct_starts_with(ostp, nstp))) 3643 return false; 3644 3645 if (is_incomplete(nstp) || is_incomplete(ostp)) 3646 return false; 3647 3648 if (nst == CHAR || nst == UCHAR) 3649 return false; /* for the sake of traditional C code */ 3650 if (ost == CHAR || ost == UCHAR) 3651 return false; /* for the sake of traditional C code */ 3652 3653 /* Allow cast between pointers to sockaddr variants. */ 3654 if (nst == STRUCT && ost == STRUCT) { 3655 const sym_t *nmem = nstp->u.sou->sou_first_member; 3656 const sym_t *omem = ostp->u.sou->sou_first_member; 3657 while (nmem != NULL && omem != NULL && 3658 types_compatible(nmem->s_type, omem->s_type, 3659 true, false, NULL)) 3660 nmem = nmem->s_next, omem = omem->s_next; 3661 if (nmem != NULL && is_byte_array(nmem->s_type)) 3662 return false; 3663 if (omem != NULL && is_byte_array(omem->s_type)) 3664 return false; 3665 if (nmem == NULL && omem == NULL) 3666 return false; 3667 } 3668 3669 if (nst == UNION || ost == UNION) { 3670 const type_t *union_tp = nst == UNION ? nstp : ostp; 3671 const type_t *other_tp = nst == UNION ? ostp : nstp; 3672 if (union_contains(union_tp, other_tp)) 3673 return false; 3674 } 3675 3676 if (is_struct_or_union(nst) && is_struct_or_union(ost)) 3677 return nstp->u.sou != ostp->u.sou; 3678 3679 enum rank_kind rk1 = type_properties(nst)->tt_rank_kind; 3680 enum rank_kind rk2 = type_properties(ost)->tt_rank_kind; 3681 if (rk1 != rk2 || rk1 == RK_NONE) 3682 return true; 3683 3684 return portable_rank_cmp(nst, ost) != 0; 3685 } 3686 3687 static void 3688 convert_pointer_from_pointer(type_t *ntp, tnode_t *tn) 3689 { 3690 const type_t *nstp = ntp->t_subt; 3691 const type_t *otp = tn->tn_type; 3692 const type_t *ostp = otp->t_subt; 3693 tspec_t nst = nstp->t_tspec; 3694 tspec_t ost = ostp->t_tspec; 3695 3696 if (nst == VOID || ost == VOID) { 3697 /* TODO: C99 behaves like C90 here. */ 3698 if (!allow_trad && !allow_c99 && (nst == FUNC || ost == FUNC)) { 3699 const char *nts, *ots; 3700 /* null pointers are already handled in convert() */ 3701 *(nst == FUNC ? &nts : &ots) = "function pointer"; 3702 *(nst == VOID ? &nts : &ots) = "'void *'"; 3703 /* conversion of %s to %s requires a cast */ 3704 warning(303, ots, nts); 3705 } 3706 return; 3707 } 3708 if (nst == FUNC && ost == FUNC) 3709 return; 3710 if (nst == FUNC || ost == FUNC) { 3711 /* converting '%s' to '%s' is questionable */ 3712 warning(229, type_name(otp), type_name(ntp)); 3713 return; 3714 } 3715 3716 if (hflag && alignment(nstp) > alignment(ostp) && 3717 ost != CHAR && ost != UCHAR && 3718 !is_incomplete(ostp) && 3719 !(nst == UNION && union_contains(nstp, ostp))) { 3720 /* converting '%s' to '%s' increases alignment ... */ 3721 warning(135, type_name(otp), type_name(ntp), 3722 alignment(ostp), alignment(nstp)); 3723 } 3724 3725 if (cflag && should_warn_about_pointer_cast(nstp, nst, ostp, ost)) { 3726 /* pointer cast from '%s' to unrelated '%s' */ 3727 warning(247, type_name(ostp), type_name(nstp)); 3728 } 3729 } 3730 3731 /* 3732 * Insert a conversion operator, which converts the type of the node 3733 * to another given type. 3734 * 3735 * Possible values for 'op': 3736 * CVT a cast-expression 3737 * binary integer promotion for one of the operands, or a usual 3738 * arithmetic conversion 3739 * binary plain or compound assignments to bit-fields 3740 * FARG 'arg' is the number of the parameter (used for warnings) 3741 * NOOP several other implicit conversions 3742 * ... 3743 */ 3744 tnode_t * 3745 convert(op_t op, int arg, type_t *tp, tnode_t *tn) 3746 { 3747 tspec_t nt = tp->t_tspec; 3748 tspec_t ot = tn->tn_type->t_tspec; 3749 3750 if (allow_trad && allow_c90 && op == FARG) 3751 check_prototype_conversion(arg, nt, ot, tp, tn); 3752 3753 if (nt == BOOL) { 3754 /* No further checks. */ 3755 3756 } else if (is_integer(nt)) { 3757 if (ot == BOOL) { 3758 /* No further checks. */ 3759 } else if (is_integer(ot)) 3760 convert_integer_from_integer(op, arg, nt, ot, tp, tn); 3761 else if (is_floating(ot)) 3762 convert_integer_from_floating(op, arg, tp, tn); 3763 else if (ot == PTR) 3764 convert_integer_from_pointer(op, nt, tp, tn); 3765 3766 } else if (is_floating(nt)) { 3767 if (is_integer(ot) && op != CVT) { 3768 /* implicit conversion from integer '%s' to ... */ 3769 query_message(19, 3770 type_name(tn->tn_type), type_name(tp)); 3771 } 3772 3773 } else if (nt == PTR) { 3774 if (is_null_pointer(tn)) { 3775 /* a null pointer may be assigned to any pointer. */ 3776 } else if (ot == PTR && op == CVT) 3777 convert_pointer_from_pointer(tp, tn); 3778 } 3779 3780 tnode_t *ntn = expr_alloc_tnode(); 3781 ntn->tn_op = CVT; 3782 ntn->tn_type = tp; 3783 ntn->tn_cast = op == CVT; 3784 ntn->tn_sys |= tn->tn_sys; 3785 ntn->u.ops.right = NULL; 3786 if (tn->tn_op != CON || nt == VOID) { 3787 ntn->u.ops.left = tn; 3788 } else { 3789 ntn->tn_op = CON; 3790 convert_constant(op, arg, ntn->tn_type, &ntn->u.value, 3791 &tn->u.value); 3792 } 3793 3794 return ntn; 3795 } 3796 3797 static void 3798 convert_constant_from_floating(op_t op, int arg, const type_t *ntp, 3799 tspec_t nt, val_t *nv, val_t *ov) 3800 { 3801 long double max = 0.0, min = 0.0; 3802 3803 switch (nt) { 3804 case CHAR: 3805 max = TARG_CHAR_MAX; min = TARG_CHAR_MIN; break; 3806 case UCHAR: 3807 max = TARG_UCHAR_MAX; min = 0; break; 3808 case SCHAR: 3809 max = TARG_SCHAR_MAX; min = TARG_SCHAR_MIN; break; 3810 case SHORT: 3811 max = TARG_SHRT_MAX; min = TARG_SHRT_MIN; break; 3812 case USHORT: 3813 max = TARG_USHRT_MAX; min = 0; break; 3814 case ENUM: 3815 case INT: 3816 max = TARG_INT_MAX; min = TARG_INT_MIN; break; 3817 case UINT: 3818 max = TARG_UINT_MAX; min = 0; break; 3819 case LONG: 3820 max = TARG_LONG_MAX; min = TARG_LONG_MIN; break; 3821 case ULONG: 3822 max = TARG_ULONG_MAX; min = 0; break; 3823 case LLONG: 3824 max = LLONG_MAX; min = LLONG_MIN; break; 3825 case ULLONG: 3826 max = ULLONG_MAX; min = 0; break; 3827 case FLOAT: 3828 case FCOMPLEX: 3829 max = FLT_MAX; min = -FLT_MAX; break; 3830 case DOUBLE: 3831 case DCOMPLEX: 3832 max = DBL_MAX; min = -DBL_MAX; break; 3833 case LDOUBLE: 3834 case LCOMPLEX: 3835 /* LINTED 248; see floating_error_value. */ 3836 max = LDBL_MAX; min = -max; break; 3837 default: 3838 lint_assert(/*CONSTCOND*/false); 3839 } 3840 if (ov->u.floating > max || ov->u.floating < min) { 3841 lint_assert(nt != LDOUBLE); 3842 const char *ot_name = type_name(gettyp(ov->v_tspec)); 3843 const char *nt_name = type_name(ntp); 3844 if (is_integer(nt)) 3845 goto after_warning; 3846 if (op == FARG) 3847 /* conversion of '%s' to '%s' is out of range, ... */ 3848 warning(295, ot_name, nt_name, arg); 3849 else 3850 /* conversion of '%s' to '%s' is out of range */ 3851 warning(119, ot_name, nt_name); 3852 after_warning: 3853 ov->u.floating = ov->u.floating > 0 ? max : min; 3854 } 3855 3856 if (nt == FLOAT || nt == FCOMPLEX) 3857 nv->u.floating = (float)ov->u.floating; 3858 else if (nt == DOUBLE || nt == DCOMPLEX) 3859 nv->u.floating = (double)ov->u.floating; 3860 else if (nt == LDOUBLE || nt == LCOMPLEX) 3861 nv->u.floating = ov->u.floating; 3862 else 3863 nv->u.integer = (int64_t)ov->u.floating; 3864 } 3865 3866 static bool 3867 convert_constant_to_floating(tspec_t nt, val_t *nv, 3868 tspec_t ot, const val_t *v) 3869 { 3870 if (nt == FLOAT) { 3871 nv->u.floating = (ot == PTR || is_uinteger(ot)) ? 3872 (float)(uint64_t)v->u.integer : (float)v->u.integer; 3873 } else if (nt == DOUBLE) { 3874 nv->u.floating = (ot == PTR || is_uinteger(ot)) ? 3875 (double)(uint64_t)v->u.integer : (double)v->u.integer; 3876 } else if (nt == LDOUBLE) { 3877 nv->u.floating = (ot == PTR || is_uinteger(ot)) 3878 ? (long double)(uint64_t)v->u.integer 3879 : (long double)v->u.integer; 3880 } else 3881 return false; 3882 return true; 3883 } 3884 3885 /* 3886 * Print a warning if bits which were set are lost due to the conversion. 3887 * This can happen with operator ORASS only. 3888 */ 3889 static void 3890 convert_constant_check_range_bitor(size_t nsz, size_t osz, const val_t *v, 3891 uint64_t xmask, op_t op) 3892 { 3893 if (nsz < osz && (v->u.integer & xmask) != 0) 3894 /* constant truncated by conversion, op '%s' */ 3895 warning(306, op_name(op)); 3896 } 3897 3898 static void 3899 convert_constant_check_range_bitand(size_t nsz, size_t osz, 3900 uint64_t xmask, const val_t *nv, 3901 tspec_t ot, const val_t *v, 3902 const type_t *tp, op_t op) 3903 { 3904 if (nsz > osz && 3905 (nv->u.integer & bit((unsigned int)(osz - 1))) != 0 && 3906 (nv->u.integer & xmask) != xmask) { 3907 /* extra bits set to 0 in conversion of '%s' to '%s', ... */ 3908 warning(309, type_name(gettyp(ot)), 3909 type_name(tp), op_name(op)); 3910 } else if (nsz < osz && 3911 (v->u.integer & xmask) != xmask && 3912 (v->u.integer & xmask) != 0) 3913 /* constant truncated by conversion, op '%s' */ 3914 warning(306, op_name(op)); 3915 } 3916 3917 static void 3918 convert_constant_check_range_signed(op_t op, int arg, 3919 const type_t *ntp, int64_t ov) 3920 { 3921 if (op == ASSIGN) 3922 /* assignment of negative constant %lld to unsigned ... */ 3923 warning(164, (long long)ov, type_name(ntp)); 3924 else if (op == INIT) 3925 /* initialization of unsigned type '%s' with negative ... */ 3926 warning(221, type_name(ntp), (long long)ov); 3927 else if (op == FARG) 3928 /* conversion of negative constant %lld to unsigned ... */ 3929 warning(296, (long long)ov, type_name(ntp), arg); 3930 else if (modtab[op].m_comparison) { 3931 /* handled by check_integer_comparison() */ 3932 } else 3933 /* conversion of negative constant %lld to unsigned ... */ 3934 warning(222, (long long)ov, type_name(ntp)); 3935 } 3936 3937 /* 3938 * Loss of significant bit(s). All truncated bits of unsigned types or all 3939 * truncated bits plus the msb of the target for signed types are considered 3940 * to be significant bits. Loss of significant bits means that at least one 3941 * of the bits was set in an unsigned type or that at least one but not all 3942 * of the bits was set in a signed type. Loss of significant bits means that 3943 * it is not possible, also not with necessary casts, to convert back to the 3944 * original type. An example for a necessary cast is: 3945 * char c; int i; c = 128; 3946 * i = c; ** yields -128 ** 3947 * i = (unsigned char)c; ** yields 128 ** 3948 */ 3949 static void 3950 warn_constant_check_range_truncated(op_t op, int arg, const type_t *tp, 3951 tspec_t ot) 3952 { 3953 if (op == ASSIGN && tp->t_bitfield) 3954 /* precision lost in bit-field assignment */ 3955 warning(166); 3956 else if (op == ASSIGN) 3957 /* constant truncated by assignment */ 3958 warning(165); 3959 else if (op == INIT && tp->t_bitfield) 3960 /* bit-field initializer does not fit */ 3961 warning(180); 3962 else if (op == INIT) 3963 /* initializer does not fit */ 3964 warning(178); 3965 else if (op == CASE) 3966 /* case label affected by conversion */ 3967 warning(196); 3968 else if (op == FARG) 3969 /* conversion of '%s' to '%s' is out of range, arg #%d */ 3970 warning(295, type_name(gettyp(ot)), type_name(tp), arg); 3971 else 3972 /* conversion of '%s' to '%s' is out of range */ 3973 warning(119, type_name(gettyp(ot)), type_name(tp)); 3974 } 3975 3976 static void 3977 warn_constant_check_range_loss(op_t op, int arg, const type_t *tp, 3978 tspec_t ot) 3979 { 3980 if (op == ASSIGN && tp->t_bitfield) 3981 /* precision lost in bit-field assignment */ 3982 warning(166); 3983 else if (op == INIT && tp->t_bitfield) 3984 /* bit-field initializer out of range */ 3985 warning(11); 3986 else if (op == CASE) 3987 /* case label affected by conversion */ 3988 warning(196); 3989 else if (op == FARG) 3990 /* conversion of '%s' to '%s' is out of range, arg #%d */ 3991 warning(295, type_name(gettyp(ot)), type_name(tp), arg); 3992 else 3993 /* conversion of '%s' to '%s' is out of range */ 3994 warning(119, type_name(gettyp(ot)), type_name(tp)); 3995 } 3996 3997 static void 3998 convert_constant_check_range(tspec_t ot, const type_t *tp, tspec_t nt, 3999 op_t op, int arg, const val_t *v, val_t *nv) 4000 { 4001 unsigned int obitsz, nbitsz; 4002 uint64_t xmask, xmsk1; 4003 4004 obitsz = size_in_bits(ot); 4005 nbitsz = tp->t_bitfield ? tp->t_bit_field_width : size_in_bits(nt); 4006 xmask = value_bits(nbitsz) ^ value_bits(obitsz); 4007 xmsk1 = value_bits(nbitsz) ^ value_bits(obitsz - 1); 4008 if (op == ORASS || op == BITOR || op == BITXOR) { 4009 convert_constant_check_range_bitor( 4010 nbitsz, obitsz, v, xmask, op); 4011 } else if (op == ANDASS || op == BITAND) { 4012 convert_constant_check_range_bitand( 4013 nbitsz, obitsz, xmask, nv, ot, v, tp, op); 4014 } else if (nt != PTR && is_uinteger(nt) && 4015 ot != PTR && !is_uinteger(ot) && 4016 v->u.integer < 0) 4017 convert_constant_check_range_signed(op, arg, 4018 tp, v->u.integer); 4019 else if (nv->u.integer != v->u.integer && nbitsz <= obitsz && 4020 (v->u.integer & xmask) != 0 && 4021 (is_uinteger(ot) || (v->u.integer & xmsk1) != xmsk1)) 4022 warn_constant_check_range_truncated(op, arg, tp, ot); 4023 else if (nv->u.integer != v->u.integer) 4024 warn_constant_check_range_loss(op, arg, tp, ot); 4025 } 4026 4027 /* Converts a typed constant to a constant of another type. */ 4028 void 4029 convert_constant(op_t op, int arg, const type_t *ntp, val_t *nv, val_t *ov) 4030 { 4031 /* 4032 * TODO: make 'ov' const; the name of this function does not suggest 4033 * that it modifies 'ov'. 4034 */ 4035 tspec_t ot = ov->v_tspec; 4036 tspec_t nt = nv->v_tspec = ntp->t_tspec; 4037 bool range_check = false; 4038 4039 if (nt == BOOL) { /* C99 6.3.1.2 */ 4040 nv->v_unsigned_since_c90 = false; 4041 nv->u.integer = is_nonzero_val(ov) ? 1 : 0; 4042 return; 4043 } 4044 4045 if (ot == FLOAT || ot == DOUBLE || ot == LDOUBLE) 4046 convert_constant_from_floating(op, arg, ntp, nt, nv, ov); 4047 else if (!convert_constant_to_floating(nt, nv, ot, ov)) { 4048 range_check = true; /* Check for lost precision. */ 4049 nv->u.integer = ov->u.integer; 4050 } 4051 4052 if (allow_trad && allow_c90 && ov->v_unsigned_since_c90 && 4053 (is_floating(nt) || ( 4054 (is_integer(nt) && !is_uinteger(nt) && 4055 portable_rank_cmp(nt, ot) > 0)))) { 4056 /* C90 treats constant as unsigned */ 4057 warning(157); 4058 ov->v_unsigned_since_c90 = false; 4059 } 4060 4061 if (is_integer(nt)) { 4062 unsigned int size = ntp->t_bitfield 4063 ? ntp->t_bit_field_width : size_in_bits(nt); 4064 nv->u.integer = convert_integer(nv->u.integer, nt, size); 4065 } 4066 4067 if (range_check && op != CVT) 4068 convert_constant_check_range(ot, ntp, nt, op, arg, ov, nv); 4069 } 4070 4071 tnode_t * 4072 build_sizeof(const type_t *tp) 4073 { 4074 unsigned int size_in_bytes = type_size_in_bits(tp) / CHAR_SIZE; 4075 tnode_t *tn = build_integer_constant(SIZEOF_TSPEC, size_in_bytes); 4076 tn->tn_system_dependent = true; 4077 debug_step("build_sizeof '%s' = %u", type_name(tp), size_in_bytes); 4078 return tn; 4079 } 4080 4081 tnode_t * 4082 build_offsetof(const type_t *tp, designation dn) 4083 { 4084 unsigned int offset_in_bits = 0; 4085 4086 if (!is_struct_or_union(tp->t_tspec)) { 4087 /* unacceptable operand of '%s' */ 4088 error(111, "offsetof"); 4089 goto proceed; 4090 } 4091 for (size_t i = 0; i < dn.dn_len; i++) { 4092 const designator *dr = dn.dn_items + i; 4093 if (dr->dr_kind == DK_SUBSCRIPT) { 4094 if (tp->t_tspec != ARRAY) 4095 goto proceed; /* silent error */ 4096 tp = tp->t_subt; 4097 offset_in_bits += (unsigned) dr->dr_subscript 4098 * type_size_in_bits(tp); 4099 } else { 4100 if (!is_struct_or_union(tp->t_tspec)) 4101 goto proceed; /* silent error */ 4102 const char *name = dr->dr_member->s_name; 4103 sym_t *mem = find_member(tp->u.sou, name); 4104 if (mem == NULL) { 4105 /* type '%s' does not have member '%s' */ 4106 error(101, name, type_name(tp)); 4107 goto proceed; 4108 } 4109 tp = mem->s_type; 4110 offset_in_bits += mem->u.s_member.sm_offset_in_bits; 4111 } 4112 } 4113 free(dn.dn_items); 4114 4115 proceed:; 4116 unsigned int offset_in_bytes = offset_in_bits / CHAR_SIZE; 4117 tnode_t *tn = build_integer_constant(SIZEOF_TSPEC, offset_in_bytes); 4118 tn->tn_system_dependent = true; 4119 return tn; 4120 } 4121 4122 unsigned int 4123 type_size_in_bits(const type_t *tp) 4124 { 4125 4126 unsigned int elem = 1; 4127 bool flex = false; 4128 lint_assert(tp != NULL); 4129 while (tp->t_tspec == ARRAY) { 4130 flex = true; /* allow c99 flex arrays [] [0] */ 4131 elem *= tp->u.dimension; 4132 tp = tp->t_subt; 4133 } 4134 if (elem == 0 && !flex) { 4135 /* cannot take size/alignment of incomplete type */ 4136 error(143); 4137 elem = 1; 4138 } 4139 4140 unsigned int elsz; 4141 switch (tp->t_tspec) { 4142 case VOID: 4143 /* cannot take size/alignment of void */ 4144 error(146); 4145 elsz = 1; 4146 break; 4147 case FUNC: 4148 /* cannot take size/alignment of function type '%s' */ 4149 error(144, type_name(tp)); 4150 elsz = 1; 4151 break; 4152 case STRUCT: 4153 case UNION: 4154 if (is_incomplete(tp)) { 4155 /* cannot take size/alignment of incomplete type */ 4156 error(143); 4157 elsz = 1; 4158 } else 4159 elsz = tp->u.sou->sou_size_in_bits; 4160 break; 4161 case ENUM: 4162 if (is_incomplete(tp)) { 4163 /* cannot take size/alignment of incomplete type */ 4164 warning(143); 4165 } 4166 /* FALLTHROUGH */ 4167 default: 4168 if (tp->t_bitfield) 4169 /* cannot take size/alignment of bit-field */ 4170 error(145); 4171 elsz = size_in_bits(tp->t_tspec); 4172 lint_assert(elsz > 0); 4173 break; 4174 } 4175 4176 return elem * elsz; 4177 } 4178 4179 /* C11 6.5.3.4, GCC */ 4180 tnode_t * 4181 build_alignof(const type_t *tp) 4182 { 4183 if (tp->t_tspec == FUNC) { 4184 /* cannot take size/alignment of function type '%s' */ 4185 error(144, type_name(tp)); 4186 return NULL; 4187 } 4188 if (tp->t_tspec == VOID) { 4189 /* cannot take size/alignment of void */ 4190 error(146); 4191 return NULL; 4192 } 4193 if (is_incomplete(tp)) { 4194 /* cannot take size/alignment of incomplete type */ 4195 error(143); 4196 return NULL; 4197 } 4198 if (tp->t_bitfield) { 4199 /* cannot take size/alignment of bit-field */ 4200 error(145); 4201 return NULL; 4202 } 4203 return build_integer_constant(SIZEOF_TSPEC, (int64_t)alignment(tp)); 4204 } 4205 4206 static tnode_t * 4207 cast_to_union(tnode_t *otn, bool sys, type_t *ntp) 4208 { 4209 4210 if (!allow_gcc) { 4211 /* union cast is a GCC extension */ 4212 error(328); 4213 return NULL; 4214 } 4215 4216 for (const sym_t *m = ntp->u.sou->sou_first_member; 4217 m != NULL; m = m->s_next) { 4218 if (types_compatible(m->s_type, otn->tn_type, 4219 false, false, NULL)) { 4220 tnode_t *ntn = build_op(CVT, sys, ntp, otn, NULL); 4221 ntn->tn_cast = true; 4222 return ntn; 4223 } 4224 } 4225 4226 /* type '%s' is not a member of '%s' */ 4227 error(329, type_name(otn->tn_type), type_name(ntp)); 4228 return NULL; 4229 } 4230 4231 // In GCC mode, allow 'nullptr + offset' as a constant expression. 4232 static tnode_t * 4233 null_pointer_offset(tnode_t *tn) 4234 { 4235 uint64_t off = 0; 4236 const tnode_t *n = tn; 4237 while ((n->tn_op == PLUS || n->tn_op == MINUS) 4238 && is_integer(n->u.ops.right->tn_type->t_tspec)) { 4239 off += (uint64_t)n->u.ops.right->u.value.u.integer; 4240 n = n->u.ops.left; 4241 } 4242 if (n->tn_type->t_tspec == PTR 4243 && n->tn_op == ADDR 4244 && n->u.ops.left->tn_op == INDIR 4245 && n->u.ops.left->u.ops.left->tn_op == CON 4246 && n->u.ops.left->u.ops.left->tn_type->t_tspec == PTR) { 4247 off += (uint64_t)n->u.ops.left->u.ops.left->u.value.u.integer; 4248 return build_integer_constant(SIZEOF_TSPEC, (int64_t)off); 4249 } 4250 return tn; 4251 } 4252 4253 tnode_t * 4254 cast(tnode_t *tn, bool sys, type_t *tp) 4255 { 4256 4257 if (tn == NULL) 4258 return NULL; 4259 4260 tn = cconv(tn); 4261 4262 lint_assert(tp != NULL); 4263 tspec_t nt = tp->t_tspec; 4264 tspec_t ot = tn->tn_type->t_tspec; 4265 4266 if (nt == VOID) { 4267 /* 4268 * C90 6.3.4, C99 6.5.4p2 and C11 6.5.4p2 allow any type to be 4269 * cast to void. The only other allowed casts are from a 4270 * scalar type to a scalar type. 4271 */ 4272 } else if (nt == UNION) 4273 return cast_to_union(tn, sys, tp); 4274 else if (nt == STRUCT || nt == ARRAY || nt == FUNC) { 4275 /* Casting to a struct is an undocumented GCC extension. */ 4276 if (!(allow_gcc && nt == STRUCT)) 4277 goto invalid_cast; 4278 } else if (is_struct_or_union(ot)) 4279 goto invalid_cast; 4280 else if (ot == VOID) { 4281 /* improper cast of void expression */ 4282 error(148); 4283 return NULL; 4284 } else if (is_integer(nt) && is_scalar(ot)) { 4285 tn = null_pointer_offset(tn); 4286 } else if (is_floating(nt) && is_arithmetic(ot)) { 4287 /* ok */ 4288 } else if (nt == PTR && is_integer(ot)) { 4289 /* ok */ 4290 } else if (nt == PTR && ot == PTR) { 4291 if (!tp->t_subt->t_const && tn->tn_type->t_subt->t_const) { 4292 if (hflag) 4293 /* cast discards 'const' from type '%s' */ 4294 warning(275, type_name(tn->tn_type)); 4295 } 4296 } else 4297 goto invalid_cast; 4298 4299 if (any_query_enabled 4300 && types_compatible(tp, tn->tn_type, false, false, NULL)) 4301 /* no-op cast from '%s' to '%s' */ 4302 query_message(6, type_name(tn->tn_type), type_name(tp)); 4303 4304 tn = convert(CVT, 0, tp, tn); 4305 tn->tn_cast = true; 4306 tn->tn_sys = sys; 4307 4308 return tn; 4309 4310 invalid_cast: 4311 /* invalid cast from '%s' to '%s' */ 4312 error(147, type_name(tn->tn_type), type_name(tp)); 4313 return NULL; 4314 } 4315 4316 void 4317 add_function_argument(function_call *call, tnode_t *arg) 4318 { 4319 /* 4320 * If there was a serious error in the expression for the argument, 4321 * create a dummy argument so the positions of the remaining arguments 4322 * will not change. 4323 */ 4324 if (arg == NULL) 4325 arg = build_integer_constant(INT, 0); 4326 4327 if (call->args_len >= call->args_cap) { 4328 call->args_cap += 8; 4329 tnode_t **new_args = expr_zero_alloc( 4330 call->args_cap * sizeof(*call->args), "tnode*[]"); 4331 if (call->args_len > 0) 4332 memcpy(new_args, call->args, 4333 call->args_len * sizeof(*call->args)); 4334 call->args = new_args; 4335 } 4336 call->args[call->args_len++] = arg; 4337 } 4338 4339 /* 4340 * Compare the type of an argument with the corresponding type of a 4341 * prototype parameter. If it is a valid combination, but both types 4342 * are not the same, insert a conversion to convert the argument into 4343 * the type of the parameter. 4344 */ 4345 static tnode_t * 4346 check_prototype_argument( 4347 int n, /* pos of arg */ 4348 type_t *tp, /* expected type (from prototype) */ 4349 tnode_t *tn) /* argument */ 4350 { 4351 tnode_t *ln = xcalloc(1, sizeof(*ln)); 4352 ln->tn_type = expr_unqualified_type(tp); 4353 ln->tn_lvalue = true; 4354 if (typeok(FARG, n, ln, tn)) { 4355 bool dowarn; 4356 if (!types_compatible(tp, tn->tn_type, 4357 true, false, (dowarn = false, &dowarn)) || dowarn) 4358 tn = convert(FARG, n, tp, tn); 4359 } 4360 free(ln); 4361 return tn; 4362 } 4363 4364 /* 4365 * Check types of all function arguments and insert conversions, 4366 * if necessary. 4367 */ 4368 static void 4369 check_function_arguments(const function_call *call) 4370 { 4371 type_t *ftp = call->func->tn_type->t_subt; 4372 4373 /* get # of parameters in the prototype */ 4374 int npar = 0; 4375 for (const sym_t *p = ftp->u.params; p != NULL; p = p->s_next) 4376 npar++; 4377 4378 int narg = (int)call->args_len; 4379 4380 const sym_t *param = ftp->u.params; 4381 if (ftp->t_proto && npar != narg && !(ftp->t_vararg && npar < narg)) { 4382 /* argument mismatch: %d %s passed, %d expected */ 4383 error(150, narg, narg != 1 ? "arguments" : "argument", npar); 4384 param = NULL; 4385 } 4386 4387 for (int i = 0; i < narg; i++) { 4388 tnode_t *arg = call->args[i]; 4389 4390 /* some things which are always not allowed */ 4391 tspec_t at = arg->tn_type->t_tspec; 4392 if (at == VOID) { 4393 /* void expressions may not be arguments, arg #%d */ 4394 error(151, i + 1); 4395 return; 4396 } 4397 if (is_struct_or_union(at) && is_incomplete(arg->tn_type)) { 4398 /* argument cannot have unknown size, arg #%d */ 4399 error(152, i + 1); 4400 return; 4401 } 4402 if (is_integer(at) && 4403 arg->tn_type->t_is_enum && 4404 is_incomplete(arg->tn_type)) { 4405 /* argument cannot have unknown size, arg #%d */ 4406 warning(152, i + 1); 4407 } 4408 4409 arg = cconv(arg); 4410 call->args[i] = arg; 4411 4412 arg = param != NULL 4413 ? check_prototype_argument(i + 1, param->s_type, arg) 4414 : promote(NOOP, true, arg); 4415 call->args[i] = arg; 4416 4417 if (param != NULL) 4418 param = param->s_next; 4419 } 4420 } 4421 4422 tnode_t * 4423 build_function_call(tnode_t *func, bool sys, function_call *call) 4424 { 4425 4426 if (func == NULL) 4427 return NULL; 4428 4429 call->func = func; 4430 check_ctype_function_call(call); 4431 4432 func = cconv(func); 4433 call->func = func; 4434 4435 if (func->tn_type->t_tspec != PTR || 4436 func->tn_type->t_subt->t_tspec != FUNC) { 4437 /* cannot call '%s', must be a function */ 4438 error(149, type_name(func->tn_type)); 4439 return NULL; 4440 } 4441 4442 check_function_arguments(call); 4443 4444 tnode_t *ntn = expr_alloc_tnode(); 4445 ntn->tn_op = CALL; 4446 ntn->tn_type = func->tn_type->t_subt->t_subt; 4447 ntn->tn_sys = sys; 4448 ntn->u.call = call; 4449 return ntn; 4450 } 4451 4452 /* 4453 * Return the value of an integral constant expression. 4454 * If the expression is not constant or its type is not an integer 4455 * type, an error message is printed. 4456 */ 4457 val_t * 4458 integer_constant(tnode_t *tn, bool required) 4459 { 4460 4461 if (tn != NULL) 4462 tn = cconv(tn); 4463 if (tn != NULL) 4464 tn = promote(NOOP, false, tn); 4465 4466 val_t *v = xcalloc(1, sizeof(*v)); 4467 4468 if (tn == NULL) { 4469 lint_assert(seen_error); 4470 debug_step("constant node is null; returning 1 instead"); 4471 v->v_tspec = INT; 4472 v->u.integer = 1; 4473 return v; 4474 } 4475 4476 v->v_tspec = tn->tn_type->t_tspec; 4477 4478 if (tn->tn_op == CON) { 4479 lint_assert(tn->tn_type->t_tspec == tn->u.value.v_tspec); 4480 if (is_integer(tn->u.value.v_tspec)) { 4481 v->v_unsigned_since_c90 = 4482 tn->u.value.v_unsigned_since_c90; 4483 v->u.integer = tn->u.value.u.integer; 4484 return v; 4485 } 4486 v->u.integer = (int64_t)tn->u.value.u.floating; 4487 } else 4488 v->u.integer = 1; 4489 4490 if (required) 4491 /* integral constant expression expected */ 4492 error(55); 4493 else 4494 /* variable array dimension is a C99/GCC extension */ 4495 c99ism(318); 4496 4497 if (!is_integer(v->v_tspec)) 4498 v->v_tspec = INT; 4499 4500 return v; 4501 } 4502 4503 static bool 4504 is_constcond_false(const tnode_t *tn, tspec_t t) 4505 { 4506 return (t == BOOL || t == INT) && 4507 tn->tn_op == CON && tn->u.value.u.integer == 0; 4508 } 4509 4510 /* 4511 * Perform some tests on expressions which can't be done in build_binary() 4512 * and functions called by build_binary(). These tests must be done here 4513 * because we need some information about the context in which the operations 4514 * are performed. 4515 * After all tests are performed and dofreeblk is true, expr() frees the 4516 * memory which is used for the expression. 4517 */ 4518 void 4519 expr(tnode_t *tn, bool vctx, bool cond, bool dofreeblk, bool is_do_while, 4520 const char *stmt_kind) 4521 { 4522 4523 if (tn == NULL) { /* in case of errors */ 4524 expr_free_all(); 4525 return; 4526 } 4527 4528 /* expr() is also called in global initializations */ 4529 if (dcs->d_kind != DLK_EXTERN && !is_do_while) 4530 check_statement_reachable(stmt_kind); 4531 4532 check_expr_misc(tn, vctx, cond, !cond, false, false, false); 4533 if (tn->tn_op == ASSIGN && !tn->tn_parenthesized) { 4534 if (hflag && cond) 4535 /* assignment in conditional context */ 4536 warning(159); 4537 } else if (tn->tn_op == CON) { 4538 if (hflag && cond && !suppress_constcond && 4539 !tn->tn_system_dependent && 4540 !(is_do_while && 4541 is_constcond_false(tn, tn->tn_type->t_tspec))) 4542 /* constant in conditional context */ 4543 warning(161); 4544 } 4545 if (!modtab[tn->tn_op].m_has_side_effect) { 4546 /* 4547 * for left operands of COMMA this warning is already printed 4548 */ 4549 if (tn->tn_op != COMMA && !vctx && !cond) 4550 check_null_effect(tn); 4551 } 4552 debug_node(tn); 4553 4554 if (dofreeblk) 4555 expr_free_all(); 4556 } 4557 4558 /* If the expression has the form '*(arr + idx)', check the array index. */ 4559 static void 4560 check_array_index(const tnode_t *indir, bool taking_address) 4561 { 4562 const tnode_t *plus, *arr, *idx; 4563 4564 if (indir->tn_op == INDIR 4565 && (plus = indir->u.ops.left, plus->tn_op == PLUS) 4566 && plus->u.ops.left->tn_op == ADDR 4567 && (arr = plus->u.ops.left->u.ops.left, true) 4568 && (arr->tn_op == STRING || arr->tn_op == NAME) 4569 && arr->tn_type->t_tspec == ARRAY 4570 && (idx = plus->u.ops.right, idx->tn_op == CON) 4571 && (!is_incomplete(arr->tn_type) || idx->u.value.u.integer < 0)) 4572 goto proceed; 4573 return; 4574 4575 proceed:; 4576 int elsz = length_in_bits(arr->tn_type->t_subt, NULL); 4577 if (elsz == 0) 4578 return; 4579 elsz /= CHAR_SIZE; 4580 4581 /* Change the unit of the index from bytes to element size. */ 4582 int64_t con = is_uinteger(idx->tn_type->t_tspec) 4583 ? (int64_t)((uint64_t)idx->u.value.u.integer / elsz) 4584 : idx->u.value.u.integer / elsz; 4585 4586 int dim = arr->tn_type->u.dimension + (taking_address ? 1 : 0); 4587 4588 if (!is_uinteger(idx->tn_type->t_tspec) && con < 0) 4589 /* array subscript %jd cannot be negative */ 4590 warning(167, (intmax_t)con); 4591 else if (dim > 0 && (uint64_t)con >= (uint64_t)dim) 4592 /* array subscript %ju cannot be > %d */ 4593 warning(168, (uintmax_t)con, dim - 1); 4594 } 4595 4596 static void 4597 check_expr_addr(const tnode_t *ln, bool szof, bool fcall) 4598 { 4599 /* XXX: Taking warn_about_unreachable into account here feels wrong. */ 4600 if (ln->tn_op == NAME && (reached || !warn_about_unreachable)) { 4601 if (!szof) 4602 mark_as_set(ln->u.sym); 4603 mark_as_used(ln->u.sym, fcall, szof); 4604 } 4605 check_array_index(ln, true); 4606 } 4607 4608 /* 4609 * If there is an asm statement in one of the compound statements around, 4610 * there may be other side effects, so don't warn. 4611 */ 4612 static bool 4613 is_asm_around(void) 4614 { 4615 for (decl_level *dl = dcs; dl != NULL; dl = dl->d_enclosing) 4616 if (dl->d_asm) 4617 return true; 4618 return false; 4619 } 4620 4621 static void 4622 check_expr_side_effect(const tnode_t *ln, bool szof) 4623 { 4624 4625 /* XXX: Taking warn_about_unreachable into account here feels wrong. */ 4626 if (ln->tn_op == NAME && (reached || !warn_about_unreachable)) { 4627 scl_t sc = ln->u.sym->s_scl; 4628 if (sc != EXTERN && sc != STATIC && 4629 !ln->u.sym->s_set && !szof && !is_asm_around()) { 4630 /* '%s' may be used before set */ 4631 warning(158, ln->u.sym->s_name); 4632 mark_as_set(ln->u.sym); 4633 } 4634 mark_as_used(ln->u.sym, false, false); 4635 } 4636 } 4637 4638 static void 4639 check_expr_assign(const tnode_t *ln, bool szof) 4640 { 4641 /* XXX: Taking warn_about_unreachable into account here feels wrong. */ 4642 if (ln->tn_op == NAME && !szof && (reached || !warn_about_unreachable)) { 4643 mark_as_set(ln->u.sym); 4644 if (ln->u.sym->s_scl == EXTERN) 4645 outusg(ln->u.sym); 4646 } 4647 check_array_index(ln, false); 4648 } 4649 4650 static void 4651 check_expr_call(const tnode_t *tn, const tnode_t *ln, 4652 bool szof, bool vctx, bool cond, bool retval_discarded) 4653 { 4654 lint_assert(ln->tn_op == ADDR); 4655 lint_assert(ln->u.ops.left->tn_op == NAME); 4656 if (!szof && !is_compiler_builtin(ln->u.ops.left->u.sym->s_name)) 4657 outcall(tn, vctx || cond, retval_discarded); 4658 4659 const function_call *call = tn->u.call; 4660 if (call->args_len == 4 || call->args_len == 5) 4661 check_snprintb(call); 4662 } 4663 4664 static void 4665 check_expr_op(op_t op, const tnode_t *ln, bool szof, bool fcall, bool eqwarn) 4666 { 4667 switch (op) { 4668 case ADDR: 4669 check_expr_addr(ln, szof, fcall); 4670 break; 4671 case LOAD: 4672 check_array_index(ln, false); 4673 /* FALLTHROUGH */ 4674 case INCBEF: 4675 case DECBEF: 4676 case INCAFT: 4677 case DECAFT: 4678 case ADDASS: 4679 case SUBASS: 4680 case MULASS: 4681 case DIVASS: 4682 case MODASS: 4683 case ANDASS: 4684 case ORASS: 4685 case XORASS: 4686 case SHLASS: 4687 case SHRASS: 4688 case REAL: 4689 case IMAG: 4690 check_expr_side_effect(ln, szof); 4691 break; 4692 case ASSIGN: 4693 check_expr_assign(ln, szof); 4694 break; 4695 case EQ: 4696 if (hflag && eqwarn) 4697 /* operator '==' found where '=' was expected */ 4698 warning(160); 4699 break; 4700 default: 4701 break; 4702 } 4703 } 4704 4705 /* 4706 * vctx ??? 4707 * cond whether the expression is a condition that 4708 * will be compared with 0 4709 * eqwarn whether the operator '==' might be a 4710 * misspelled '=' 4711 * fcall whether the expression is a function call 4712 * retval_discarded whether the return value of a function call 4713 * is discarded; such calls will be analyzed by 4714 * lint2 in messages 4, 8 and 9 4715 * szof whether the expression is part of a sizeof 4716 * expression, which means that its value is 4717 * discarded since only the type is relevant 4718 */ 4719 void 4720 check_expr_misc(const tnode_t *tn, bool vctx, bool cond, 4721 bool eqwarn, bool fcall, bool retval_discarded, bool szof) 4722 { 4723 4724 if (tn == NULL) 4725 return; 4726 op_t op = tn->tn_op; 4727 if (op == NAME || op == CON || op == STRING) 4728 return; 4729 bool is_direct = op == CALL 4730 && tn->u.call->func->tn_op == ADDR 4731 && tn->u.call->func->u.ops.left->tn_op == NAME; 4732 if (op == CALL) { 4733 const function_call *call = tn->u.call; 4734 if (is_direct) 4735 check_expr_call(tn, call->func, 4736 szof, vctx, cond, retval_discarded); 4737 bool discard = op == CVT && tn->tn_type->t_tspec == VOID; 4738 check_expr_misc(call->func, false, false, false, is_direct, 4739 discard, szof); 4740 for (size_t i = 0, n = call->args_len; i < n; i++) 4741 check_expr_misc(call->args[i], 4742 true, false, false, false, false, szof); 4743 return; 4744 } 4745 4746 lint_assert(has_operands(tn)); 4747 tnode_t *ln = tn->u.ops.left; 4748 tnode_t *rn = tn->u.ops.right; 4749 check_expr_op(op, ln, szof, fcall, eqwarn); 4750 4751 const mod_t *mp = &modtab[op]; 4752 bool cvctx = mp->m_value_context; 4753 bool ccond = mp->m_compares_with_zero; 4754 bool eq = mp->m_warn_if_operand_eq && 4755 !ln->tn_parenthesized && 4756 rn != NULL && !rn->tn_parenthesized; 4757 4758 /* 4759 * Values of operands of ':' are not used if the type of at least 4760 * one of the operands (for GCC compatibility) is 'void'. 4761 * 4762 * XXX test/value context of QUEST should probably be used as 4763 * context for both operands of COLON. 4764 */ 4765 if (op == COLON && tn->tn_type->t_tspec == VOID) 4766 cvctx = ccond = false; 4767 bool discard = op == CVT && tn->tn_type->t_tspec == VOID; 4768 check_expr_misc(ln, cvctx, ccond, eq, is_direct, discard, szof); 4769 4770 switch (op) { 4771 case LOGAND: 4772 case LOGOR: 4773 check_expr_misc(rn, false, true, eq, false, false, szof); 4774 break; 4775 case COLON: 4776 check_expr_misc(rn, cvctx, ccond, eq, false, false, szof); 4777 break; 4778 case COMMA: 4779 check_expr_misc(rn, vctx, cond, false, false, false, szof); 4780 break; 4781 default: 4782 if (mp->m_binary) 4783 check_expr_misc(rn, true, false, eq, false, false, 4784 szof); 4785 break; 4786 } 4787 } 4788 4789 /* 4790 * Return whether the expression can be used for static initialization. 4791 * 4792 * Constant initialization expressions must be constant or an address 4793 * of a static object with an optional offset. In the first case, 4794 * the result is returned in *offsp. In the second case, the static 4795 * object is returned in *symp and the offset in *offsp. 4796 * 4797 * The expression can consist of PLUS, MINUS, ADDR, NAME, STRING and 4798 * CON. Type conversions are allowed if they do not change binary 4799 * representation (including width). 4800 * 4801 * C99 6.6 "Constant expressions" 4802 * C99 6.7.8p4 restricts initializers for static storage duration 4803 */ 4804 bool 4805 constant_addr(const tnode_t *tn, const sym_t **symp, ptrdiff_t *offsp) 4806 { 4807 const sym_t *sym; 4808 ptrdiff_t offs1, offs2; 4809 tspec_t t, ot; 4810 4811 switch (tn->tn_op) { 4812 case MINUS: 4813 if (tn->u.ops.right->tn_op == CVT) 4814 return constant_addr(tn->u.ops.right, symp, offsp); 4815 else if (tn->u.ops.right->tn_op != CON) 4816 return false; 4817 /* FALLTHROUGH */ 4818 case PLUS: 4819 offs1 = offs2 = 0; 4820 if (tn->u.ops.left->tn_op == CON) { 4821 offs1 = (ptrdiff_t)tn->u.ops.left->u.value.u.integer; 4822 if (!constant_addr(tn->u.ops.right, &sym, &offs2)) 4823 return false; 4824 } else if (tn->u.ops.right->tn_op == CON) { 4825 offs2 = (ptrdiff_t)tn->u.ops.right->u.value.u.integer; 4826 if (tn->tn_op == MINUS) 4827 offs2 = -offs2; 4828 if (!constant_addr(tn->u.ops.left, &sym, &offs1)) 4829 return false; 4830 } else { 4831 return false; 4832 } 4833 *symp = sym; 4834 *offsp = offs1 + offs2; 4835 return true; 4836 case ADDR: 4837 if (tn->u.ops.left->tn_op == NAME) { 4838 *symp = tn->u.ops.left->u.sym; 4839 *offsp = 0; 4840 return true; 4841 } else { 4842 /* 4843 * If this were the front end of a compiler, we would 4844 * return a label instead of 0, at least if 4845 * 'tn->u.ops.left->tn_op == STRING'. 4846 */ 4847 *symp = NULL; 4848 *offsp = 0; 4849 return true; 4850 } 4851 case CVT: 4852 t = tn->tn_type->t_tspec; 4853 ot = tn->u.ops.left->tn_type->t_tspec; 4854 if ((!is_integer(t) && t != PTR) || 4855 (!is_integer(ot) && ot != PTR)) { 4856 return false; 4857 } 4858 #if 0 4859 /*- 4860 * consider: 4861 * struct foo { 4862 * unsigned char a; 4863 * } f = { 4864 * (unsigned char)(unsigned long) 4865 * (&(((struct foo *)0)->a)) 4866 * }; 4867 * since psize(unsigned long) != psize(unsigned char), 4868 * this fails. 4869 */ 4870 else if (psize(t) != psize(ot)) 4871 return -1; 4872 #endif 4873 return constant_addr(tn->u.ops.left, symp, offsp); 4874 default: 4875 return false; 4876 } 4877 } 4878 4879 /* Append s2 to s1, then free s2. */ 4880 buffer * 4881 cat_strings(buffer *s1, buffer *s2) 4882 { 4883 4884 if ((s1->data != NULL) != (s2->data != NULL)) { 4885 /* cannot concatenate wide and regular string literals */ 4886 error(292); 4887 return s1; 4888 } 4889 4890 if (s1->data != NULL) { 4891 while (s1->len + s2->len + 1 > s1->cap) 4892 s1->cap *= 2; 4893 s1->data = xrealloc(s1->data, s1->cap); 4894 memcpy(s1->data + s1->len, s2->data, s2->len + 1); 4895 free(s2->data); 4896 } 4897 s1->len += s2->len; 4898 free(s2); 4899 4900 return s1; 4901 } 4902 4903 4904 typedef struct stmt_expr { 4905 memory_pool se_mem; 4906 sym_t *se_sym; 4907 struct stmt_expr *se_enclosing; 4908 } stmt_expr; 4909 4910 static stmt_expr *stmt_exprs; 4911 4912 void 4913 begin_statement_expr(void) 4914 { 4915 debug_enter(); 4916 4917 stmt_expr *se = xmalloc(sizeof(*se)); 4918 se->se_mem = expr_save_memory(); 4919 se->se_sym = NULL; 4920 se->se_enclosing = stmt_exprs; 4921 stmt_exprs = se; 4922 } 4923 4924 void 4925 do_statement_expr(tnode_t *tn) 4926 { 4927 block_level--; 4928 mem_block_level--; 4929 stmt_exprs->se_sym = tn != NULL 4930 ? mktempsym(block_dup_type(tn->tn_type)) 4931 : NULL; /* after a syntax error */ 4932 mem_block_level++; 4933 block_level++; 4934 /* '({ ... })' is a GCC extension */ 4935 gnuism(320); 4936 } 4937 4938 tnode_t * 4939 end_statement_expr(void) 4940 { 4941 tnode_t *tn; 4942 4943 stmt_expr *se = stmt_exprs; 4944 if (se->se_sym == NULL) { 4945 tn = NULL; /* after a syntax error */ 4946 goto end; 4947 } 4948 4949 tn = build_name(se->se_sym, false); 4950 (void)expr_save_memory(); /* leak */ 4951 expr_restore_memory(se->se_mem); 4952 stmt_exprs = se->se_enclosing; 4953 free(se); 4954 4955 end: 4956 debug_leave(); 4957 return tn; 4958 } 4959 4960 bool 4961 in_statement_expr(void) 4962 { 4963 return stmt_exprs != NULL; 4964 } 4965
Indexes created Wed Sep 24 05:09:52 GMT 2025