tree.c revision 1.656
1 /* $NetBSD: tree.c,v 1.656 2024/10/12 09:45:25 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 1.656 2024/10/12 09:45:25 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 return; 1260 1261 /* maximum value %d of '%s' does not match maximum array index %d */ 1262 warning(348, (int)max_enum_value, type_name(rtp), max_array_index); 1263 print_previous_declaration(max_ec); 1264 } 1265 1266 static tnode_t * 1267 build_plus_minus(op_t op, bool sys, tnode_t *ln, tnode_t *rn) 1268 { 1269 1270 if (rn->tn_type->t_tspec == PTR && is_integer(ln->tn_type->t_tspec)) { 1271 tnode_t *tmp = ln; 1272 ln = rn; 1273 rn = tmp; 1274 /* pointer addition has integer on the left-hand side */ 1275 query_message(5); 1276 } 1277 1278 /* pointer +- integer */ 1279 tspec_t lt = ln->tn_type->t_tspec; 1280 tspec_t rt = rn->tn_type->t_tspec; 1281 if (lt == PTR && rt != PTR) { 1282 lint_assert(is_integer(rt)); 1283 1284 check_ctype_macro_invocation(ln, rn); 1285 check_enum_array_index(ln, rn); 1286 1287 tnode_t *elsz = subt_size_in_bytes(ln->tn_type); 1288 tspec_t szt = elsz->tn_type->t_tspec; 1289 if (rt != szt && rt != unsigned_type(szt)) 1290 rn = convert(NOOP, 0, elsz->tn_type, rn); 1291 1292 tnode_t *prod = build_op(MULT, sys, rn->tn_type, rn, elsz); 1293 if (rn->tn_op == CON) 1294 prod = fold_constant_integer(prod); 1295 1296 return build_op(op, sys, ln->tn_type, ln, prod); 1297 } 1298 1299 /* pointer - pointer */ 1300 if (rt == PTR) { 1301 lint_assert(lt == PTR); 1302 lint_assert(op == MINUS); 1303 1304 type_t *ptrdiff = gettyp(PTRDIFF_TSPEC); 1305 tnode_t *raw_diff = build_op(op, sys, ptrdiff, ln, rn); 1306 if (ln->tn_op == CON && rn->tn_op == CON) 1307 raw_diff = fold_constant_integer(raw_diff); 1308 1309 tnode_t *elsz = subt_size_in_bytes(ln->tn_type); 1310 balance(NOOP, &raw_diff, &elsz); 1311 1312 return build_op(DIV, sys, ptrdiff, raw_diff, elsz); 1313 } 1314 1315 return build_op(op, sys, ln->tn_type, ln, rn); 1316 } 1317 1318 static tnode_t * 1319 build_bit_shift(op_t op, bool sys, tnode_t *ln, tnode_t *rn) 1320 { 1321 1322 if (!allow_c90 && rn->tn_type->t_tspec != INT) 1323 // XXX: C1978 7.5 says: "Both [operators] perform the usual 1324 // arithmetic conversions on their operands." 1325 // TODO: Add a test to exercise this part of the code. 1326 rn = convert(NOOP, 0, gettyp(INT), rn); 1327 return build_op(op, sys, ln->tn_type, ln, rn); 1328 } 1329 1330 static bool 1331 is_null_pointer(const tnode_t *tn) 1332 { 1333 tspec_t t = tn->tn_type->t_tspec; 1334 1335 // TODO: Investigate how other pointers are stored, in particular, 1336 // whether a pointer constant can have a non-zero value. 1337 // If not, simplify the code below. 1338 return ((t == PTR && tn->tn_type->t_subt->t_tspec == VOID) 1339 || is_integer(t)) 1340 && (tn->tn_op == CON && tn->u.value.u.integer == 0); 1341 } 1342 1343 /* Return a type based on tp1, with added qualifiers from tp2. */ 1344 static type_t * 1345 merge_qualifiers(type_t *tp1, const type_t *tp2) 1346 { 1347 1348 lint_assert(tp1->t_tspec == PTR); 1349 lint_assert(tp2->t_tspec == PTR); 1350 1351 bool c1 = tp1->t_subt->t_const; 1352 bool c2 = tp2->t_subt->t_const; 1353 bool v1 = tp1->t_subt->t_volatile; 1354 bool v2 = tp2->t_subt->t_volatile; 1355 1356 if (c1 == (c1 | c2) && v1 == (v1 | v2)) 1357 return tp1; 1358 1359 type_t *nstp = expr_dup_type(tp1->t_subt); 1360 nstp->t_const |= c2; 1361 nstp->t_volatile |= v2; 1362 1363 type_t *ntp = expr_dup_type(tp1); 1364 ntp->t_subt = nstp; 1365 return ntp; 1366 } 1367 1368 /* See C99 6.5.15 "Conditional operator". */ 1369 static tnode_t * 1370 build_colon(bool sys, tnode_t *ln, tnode_t *rn) 1371 { 1372 tspec_t lt = ln->tn_type->t_tspec; 1373 tspec_t rt = rn->tn_type->t_tspec; 1374 1375 type_t *tp; 1376 if (is_arithmetic(lt) && is_arithmetic(rt)) 1377 /* The operands were already balanced in build_binary. */ 1378 tp = ln->tn_type; 1379 else if (lt == BOOL && rt == BOOL) 1380 tp = ln->tn_type; 1381 else if (lt == VOID || rt == VOID) 1382 tp = gettyp(VOID); 1383 else if (is_struct_or_union(lt)) { 1384 lint_assert(is_struct_or_union(rt)); 1385 lint_assert(ln->tn_type->u.sou == rn->tn_type->u.sou); 1386 if (is_incomplete(ln->tn_type)) { 1387 /* unknown operand size, op '%s' */ 1388 error(138, op_name(COLON)); 1389 return NULL; 1390 } 1391 tp = ln->tn_type; 1392 } else if (lt == PTR && is_integer(rt)) { 1393 if (rt != PTRDIFF_TSPEC) 1394 rn = convert(NOOP, 0, gettyp(PTRDIFF_TSPEC), rn); 1395 tp = ln->tn_type; 1396 } else if (rt == PTR && is_integer(lt)) { 1397 if (lt != PTRDIFF_TSPEC) 1398 ln = convert(NOOP, 0, gettyp(PTRDIFF_TSPEC), ln); 1399 tp = rn->tn_type; 1400 } else if (lt == PTR && is_null_pointer(rn)) 1401 tp = merge_qualifiers(ln->tn_type, rn->tn_type); 1402 else if (rt == PTR && is_null_pointer(ln)) 1403 tp = merge_qualifiers(rn->tn_type, ln->tn_type); 1404 else if (lt == PTR && ln->tn_type->t_subt->t_tspec == VOID) 1405 tp = merge_qualifiers(ln->tn_type, rn->tn_type); 1406 else if (rt == PTR && rn->tn_type->t_subt->t_tspec == VOID) 1407 tp = merge_qualifiers(rn->tn_type, ln->tn_type); 1408 else { 1409 /* 1410 * XXX For now we simply take the left type. This is probably 1411 * wrong, if one type contains a function prototype and the 1412 * other one, at the same place, only an old-style declaration. 1413 */ 1414 tp = merge_qualifiers(ln->tn_type, rn->tn_type); 1415 } 1416 1417 return build_op(COLON, sys, tp, ln, rn); 1418 } 1419 1420 /* TODO: check for varargs */ 1421 static bool 1422 is_cast_redundant(const tnode_t *tn) 1423 { 1424 const type_t *ntp = tn->tn_type, *otp = tn->u.ops.left->tn_type; 1425 tspec_t nt = ntp->t_tspec, ot = otp->t_tspec; 1426 1427 if (nt == BOOL || ot == BOOL) 1428 return nt == BOOL && ot == BOOL; 1429 1430 if (is_integer(nt) && is_integer(ot)) { 1431 unsigned int nw = width_in_bits(ntp), ow = width_in_bits(otp); 1432 if (is_uinteger(nt) == is_uinteger(ot)) 1433 return nw >= ow; 1434 return is_uinteger(ot) && nw > ow; 1435 } 1436 1437 if (is_complex(nt) || is_complex(ot)) 1438 return is_complex(nt) && is_complex(ot) && 1439 size_in_bits(nt) >= size_in_bits(ot); 1440 1441 if (is_floating(nt) && is_floating(ot)) 1442 return size_in_bits(nt) >= size_in_bits(ot); 1443 1444 if (nt == PTR && ot == PTR) { 1445 if (!ntp->t_subt->t_const && otp->t_subt->t_const) 1446 return false; 1447 if (!ntp->t_subt->t_volatile && otp->t_subt->t_volatile) 1448 return false; 1449 1450 if (ntp->t_subt->t_tspec == VOID || 1451 otp->t_subt->t_tspec == VOID || 1452 types_compatible(ntp->t_subt, otp->t_subt, 1453 false, false, NULL)) 1454 return true; 1455 } 1456 1457 return false; 1458 } 1459 1460 static bool 1461 is_assignment(op_t op) 1462 { 1463 1464 return op == ASSIGN || 1465 op == MULASS || 1466 op == DIVASS || 1467 op == MODASS || 1468 op == ADDASS || 1469 op == SUBASS || 1470 op == SHLASS || 1471 op == SHRASS || 1472 op == ANDASS || 1473 op == XORASS || 1474 op == ORASS || 1475 op == RETURN || 1476 op == INIT; 1477 } 1478 1479 static tnode_t * 1480 build_assignment(op_t op, bool sys, tnode_t *ln, tnode_t *rn) 1481 { 1482 1483 tspec_t lt = ln->tn_type->t_tspec; 1484 tspec_t rt = rn->tn_type->t_tspec; 1485 1486 if (any_query_enabled && is_assignment(rn->tn_op)) { 1487 /* chained assignment with '%s' and '%s' */ 1488 query_message(10, op_name(op), op_name(rn->tn_op)); 1489 } 1490 1491 if ((op == ADDASS || op == SUBASS) && lt == PTR) { 1492 lint_assert(is_integer(rt)); 1493 tnode_t *ctn = subt_size_in_bytes(ln->tn_type); 1494 if (rn->tn_type->t_tspec != ctn->tn_type->t_tspec) 1495 rn = convert(NOOP, 0, ctn->tn_type, rn); 1496 rn = build_op(MULT, sys, rn->tn_type, rn, ctn); 1497 if (rn->u.ops.left->tn_op == CON) 1498 rn = fold_constant_integer(rn); 1499 } 1500 1501 if ((op == ASSIGN || op == RETURN || op == INIT) && 1502 (lt == STRUCT || rt == STRUCT)) { 1503 lint_assert(lt == rt); 1504 lint_assert(ln->tn_type->u.sou == rn->tn_type->u.sou); 1505 if (is_incomplete(ln->tn_type)) { 1506 if (op == RETURN) 1507 /* cannot return incomplete type */ 1508 error(212); 1509 else 1510 /* unknown operand size, op '%s' */ 1511 error(138, op_name(op)); 1512 return NULL; 1513 } 1514 } 1515 1516 if (op == SHLASS && hflag && allow_trad && allow_c90 1517 && portable_rank_cmp(lt, rt) < 0) 1518 /* semantics of '%s' change in C90; ... */ 1519 warning(118, "<<="); 1520 1521 if (op != SHLASS && op != SHRASS 1522 && (op == ASSIGN || lt != PTR) 1523 && (lt != rt || (ln->tn_type->t_bitfield && rn->tn_op == CON))) { 1524 rn = convert(op, 0, ln->tn_type, rn); 1525 rt = lt; 1526 } 1527 1528 if (is_query_enabled[20] 1529 && 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, bool lparen, op_t rop, bool rparen) 1585 { 1586 1587 if (op == SHL || op == SHR) { 1588 if (!lparen && (lop == PLUS || lop == MINUS)) 1589 return true; 1590 if (!rparen && (rop == PLUS || rop == MINUS)) 1591 return true; 1592 return false; 1593 } 1594 1595 if (op == LOGOR) { 1596 if (!lparen && lop == LOGAND) 1597 return true; 1598 if (!rparen && rop == LOGAND) 1599 return true; 1600 return false; 1601 } 1602 1603 lint_assert(op == BITAND || op == BITXOR || op == BITOR); 1604 if (!lparen && lop != op) { 1605 if (lop == PLUS || lop == MINUS) 1606 return true; 1607 if (lop == BITAND || lop == BITXOR) 1608 return true; 1609 } 1610 if (!rparen && rop != op) { 1611 if (rop == PLUS || rop == MINUS) 1612 return true; 1613 if (rop == BITAND || rop == BITXOR) 1614 return true; 1615 } 1616 return false; 1617 } 1618 1619 /* 1620 * Print a warning if the given node has operands which should be 1621 * parenthesized. 1622 * 1623 * XXX Does not work if an operand is a constant expression. Constant 1624 * expressions are already folded. 1625 */ 1626 static void 1627 check_precedence_confusion(tnode_t *tn) 1628 { 1629 tnode_t *ln, *rn; 1630 1631 if (!hflag) 1632 return; 1633 1634 debug_node(tn); 1635 1636 lint_assert(is_binary(tn)); 1637 for (ln = tn->u.ops.left; ln->tn_op == CVT; ln = ln->u.ops.left) 1638 continue; 1639 for (rn = tn->u.ops.right; rn->tn_op == CVT; rn = rn->u.ops.left) 1640 continue; 1641 1642 if (is_confusing_precedence(tn->tn_op, 1643 ln->tn_op, ln->tn_parenthesized, 1644 rn->tn_op, rn->tn_parenthesized)) { 1645 /* precedence confusion possible: parenthesize! */ 1646 warning(169); 1647 } 1648 } 1649 1650 static tnode_t * 1651 fold_constant_compare_zero(tnode_t *tn) 1652 { 1653 1654 val_t *v = xcalloc(1, sizeof(*v)); 1655 v->v_tspec = tn->tn_type->t_tspec; 1656 lint_assert(v->v_tspec == INT || (Tflag && v->v_tspec == BOOL)); 1657 1658 lint_assert(has_operands(tn)); 1659 bool l = constant_is_nonzero(tn->u.ops.left); 1660 bool r = is_binary(tn) && constant_is_nonzero(tn->u.ops.right); 1661 1662 switch (tn->tn_op) { 1663 case NOT: 1664 if (hflag && !suppress_constcond) 1665 /* constant operand to '!' */ 1666 warning(239); 1667 v->u.integer = !l ? 1 : 0; 1668 break; 1669 case LOGAND: 1670 v->u.integer = l && r ? 1 : 0; 1671 break; 1672 case LOGOR: 1673 v->u.integer = l || r ? 1 : 0; 1674 break; 1675 default: 1676 lint_assert(/*CONSTCOND*/false); 1677 } 1678 1679 return build_constant(tn->tn_type, v); 1680 } 1681 1682 static long double 1683 floating_error_value(tspec_t t, long double lv) 1684 { 1685 if (t == FLOAT) 1686 return lv < 0 ? -FLT_MAX : FLT_MAX; 1687 if (t == DOUBLE) 1688 return lv < 0 ? -DBL_MAX : DBL_MAX; 1689 /* 1690 * When NetBSD is cross-built in MKLINT=yes mode on x86_64 for sparc64, 1691 * tools/lint checks this code while building usr.bin/xlint. In that 1692 * situation, lint uses the preprocessor for sparc64, in which the type 1693 * 'long double' is IEEE-754-binary128, affecting the macro LDBL_MAX 1694 * below. The type 'long double', as well as the strtold 1695 * implementation, comes from the host platform x86_64 though, where 1696 * 'long double' consumes 128 bits as well but only uses 80 of them. 1697 * The exponent range of the two 'long double' types is the same, but 1698 * the maximum finite value differs due to the extended precision on 1699 * sparc64. 1700 * 1701 * To properly handle the data types of the target platform, lint would 1702 * have to implement the floating-point types in a platform-independent 1703 * way, which is not worth the effort, given how few programs 1704 * practically use 'long double'. 1705 */ 1706 /* LINTED 248: floating-point constant out of range */ 1707 long double max = LDBL_MAX; 1708 return lv < 0 ? -max : max; 1709 } 1710 1711 static bool 1712 is_floating_overflow(tspec_t t, long double val) 1713 { 1714 if (fpe != 0 || isfinite(val) == 0) 1715 return true; 1716 if (t == FLOAT && (val > FLT_MAX || val < -FLT_MAX)) 1717 return true; 1718 if (t == DOUBLE && (val > DBL_MAX || val < -DBL_MAX)) 1719 return true; 1720 return false; 1721 } 1722 1723 static tnode_t * 1724 fold_constant_floating(tnode_t *tn) 1725 { 1726 1727 fpe = 0; 1728 1729 tspec_t t = tn->tn_type->t_tspec; 1730 1731 val_t *v = xcalloc(1, sizeof(*v)); 1732 v->v_tspec = t; 1733 1734 lint_assert(is_floating(t)); 1735 lint_assert(has_operands(tn)); 1736 lint_assert(t == tn->u.ops.left->tn_type->t_tspec); 1737 lint_assert(!is_binary(tn) || t == tn->u.ops.right->tn_type->t_tspec); 1738 1739 long double lv = tn->u.ops.left->u.value.u.floating; 1740 long double rv = is_binary(tn) ? tn->u.ops.right->u.value.u.floating 1741 : 0.0; 1742 1743 switch (tn->tn_op) { 1744 case UPLUS: 1745 v->u.floating = lv; 1746 break; 1747 case UMINUS: 1748 v->u.floating = -lv; 1749 break; 1750 case MULT: 1751 v->u.floating = lv * rv; 1752 break; 1753 case DIV: 1754 if (rv == 0.0) { 1755 /* division by 0 */ 1756 error(139); 1757 v->u.floating = floating_error_value(t, lv); 1758 } else { 1759 v->u.floating = lv / rv; 1760 } 1761 break; 1762 case PLUS: 1763 v->u.floating = lv + rv; 1764 break; 1765 case MINUS: 1766 v->u.floating = lv - rv; 1767 break; 1768 case LT: 1769 v->u.integer = lv < rv ? 1 : 0; 1770 break; 1771 case LE: 1772 v->u.integer = lv <= rv ? 1 : 0; 1773 break; 1774 case GE: 1775 v->u.integer = lv >= rv ? 1 : 0; 1776 break; 1777 case GT: 1778 v->u.integer = lv > rv ? 1 : 0; 1779 break; 1780 case EQ: 1781 v->u.integer = lv == rv ? 1 : 0; 1782 break; 1783 case NE: 1784 v->u.integer = lv != rv ? 1 : 0; 1785 break; 1786 default: 1787 lint_assert(/*CONSTCOND*/false); 1788 } 1789 1790 // XXX: Must not access u.floating after setting u.integer. 1791 lint_assert(fpe != 0 || isnan(v->u.floating) == 0); 1792 if (is_complex(v->v_tspec)) { 1793 /* 1794 * Don't warn, as lint doesn't model the imaginary part of 1795 * complex numbers. 1796 */ 1797 fpe = 0; 1798 } else if (is_floating_overflow(t, v->u.floating)) { 1799 /* operator '%s' produces floating point overflow */ 1800 warning(142, op_name(tn->tn_op)); 1801 v->u.floating = floating_error_value(t, v->u.floating); 1802 fpe = 0; 1803 } 1804 1805 return build_constant(tn->tn_type, v); 1806 } 1807 1808 static void 1809 use(const tnode_t *tn) 1810 { 1811 if (tn == NULL) 1812 return; 1813 switch (tn->tn_op) { 1814 case NAME: 1815 mark_as_used(tn->u.sym, false /* XXX */, false /* XXX */); 1816 break; 1817 case CON: 1818 case STRING: 1819 break; 1820 case CALL:; 1821 const function_call *call = tn->u.call; 1822 for (size_t i = 0, n = call->args_len; i < n; i++) 1823 use(call->args[i]); 1824 break; 1825 default: 1826 lint_assert(has_operands(tn)); 1827 use(tn->u.ops.left); 1828 if (is_binary(tn)) 1829 use(tn->u.ops.right); 1830 } 1831 } 1832 1833 /* 1834 * Create a tree node for a binary operator and its two operands. Also called 1835 * for unary operators; in that case rn is NULL. 1836 * 1837 * Function calls, sizeof and casts are handled elsewhere. 1838 */ 1839 tnode_t * 1840 build_binary(tnode_t *ln, op_t op, bool sys, tnode_t *rn) 1841 { 1842 const mod_t *mp = &modtab[op]; 1843 1844 /* If there was an error in one of the operands, return. */ 1845 if (ln == NULL || (mp->m_binary && rn == NULL)) 1846 return NULL; 1847 1848 if (mp->m_value_context || mp->m_compares_with_zero) 1849 ln = cconv(ln); 1850 if (mp->m_binary && op != ARROW && op != POINT) 1851 rn = cconv(rn); 1852 1853 if (mp->m_comparison) 1854 check_integer_comparison(op, ln, rn); 1855 1856 if (mp->m_value_context || mp->m_compares_with_zero) 1857 ln = promote(op, false, ln); 1858 if (mp->m_binary && op != ARROW && op != POINT && 1859 op != ASSIGN && op != RETURN && op != INIT) 1860 rn = promote(op, false, rn); 1861 1862 if (mp->m_warn_if_left_unsigned_in_c90 && 1863 ln->tn_op == CON && ln->u.value.v_unsigned_since_c90) { 1864 /* C90 treats constant as unsigned, op '%s' */ 1865 warning(218, op_name(op)); 1866 ln->u.value.v_unsigned_since_c90 = false; 1867 } 1868 if (mp->m_warn_if_right_unsigned_in_c90 && 1869 rn->tn_op == CON && rn->u.value.v_unsigned_since_c90) { 1870 /* C90 treats constant as unsigned, op '%s' */ 1871 warning(218, op_name(op)); 1872 rn->u.value.v_unsigned_since_c90 = false; 1873 } 1874 1875 if (mp->m_balance_operands || (!allow_c90 && (op == SHL || op == SHR))) 1876 balance(op, &ln, &rn); 1877 1878 if (!typeok(op, 0, ln, rn)) 1879 return NULL; 1880 1881 tnode_t *ntn; 1882 switch (op) { 1883 case POINT: 1884 case ARROW: 1885 ntn = build_struct_access(op, sys, ln, rn); 1886 break; 1887 case NOT: 1888 if (ln->tn_op == ASSIGN && ln->u.ops.right->tn_op == CON) { 1889 /* constant assignment of type '%s' in operand ... */ 1890 warning(382, type_name(ln->tn_type), 1891 is_nonzero_val(&ln->u.ops.right->u.value) 1892 ? "true" : "false"); 1893 } 1894 ntn = build_op(op, sys, gettyp(Tflag ? BOOL : INT), ln, NULL); 1895 break; 1896 case INCAFT: 1897 case DECAFT: 1898 case INCBEF: 1899 case DECBEF: 1900 ntn = build_prepost_incdec(op, sys, ln); 1901 break; 1902 case ADDR: 1903 ntn = build_address(sys, ln, false); 1904 break; 1905 case INDIR: 1906 ntn = build_op(INDIR, sys, ln->tn_type->t_subt, ln, NULL); 1907 break; 1908 case PLUS: 1909 case MINUS: 1910 ntn = build_plus_minus(op, sys, ln, rn); 1911 break; 1912 case SHL: 1913 case SHR: 1914 ntn = build_bit_shift(op, sys, ln, rn); 1915 break; 1916 case COLON: 1917 ntn = build_colon(sys, ln, rn); 1918 break; 1919 case ASSIGN: 1920 case MULASS: 1921 case DIVASS: 1922 case MODASS: 1923 case ADDASS: 1924 case SUBASS: 1925 case SHLASS: 1926 case SHRASS: 1927 case ANDASS: 1928 case XORASS: 1929 case ORASS: 1930 case RETURN: 1931 case INIT: 1932 ntn = build_assignment(op, sys, ln, rn); 1933 break; 1934 case COMMA: 1935 if (any_query_enabled) { 1936 /* comma operator with types '%s' and '%s' */ 1937 query_message(12, 1938 type_name(ln->tn_type), type_name(rn->tn_type)); 1939 } 1940 /* FALLTHROUGH */ 1941 case QUEST: 1942 ntn = build_op(op, sys, rn->tn_type, ln, rn); 1943 break; 1944 case REAL: 1945 case IMAG: 1946 ntn = build_real_imag(op, sys, ln); 1947 break; 1948 default: 1949 lint_assert(mp->m_binary == (rn != NULL)); 1950 type_t *rettp = mp->m_returns_bool 1951 ? gettyp(Tflag ? BOOL : INT) : ln->tn_type; 1952 ntn = build_op(op, sys, rettp, ln, rn); 1953 break; 1954 } 1955 1956 if (ntn == NULL) 1957 return NULL; 1958 1959 if (mp->m_possible_precedence_confusion) 1960 check_precedence_confusion(ntn); 1961 1962 if (hflag && !suppress_constcond && 1963 mp->m_compares_with_zero && 1964 (ln->tn_op == CON || 1965 (mp->m_binary && op != QUEST && rn->tn_op == CON)) && 1966 /* XXX: rn->tn_system_dependent should be checked as well */ 1967 !ln->tn_system_dependent) 1968 /* constant in conditional context */ 1969 warning(161); 1970 1971 if (mp->m_fold_constant_operands && ln->tn_op == CON) { 1972 if (!mp->m_binary || rn->tn_op == CON) { 1973 if (mp->m_compares_with_zero) 1974 ntn = fold_constant_compare_zero(ntn); 1975 else if (is_floating(ntn->tn_type->t_tspec)) 1976 ntn = fold_constant_floating(ntn); 1977 else 1978 ntn = fold_constant_integer(ntn); 1979 } else if (op == QUEST) { 1980 lint_assert(has_operands(rn)); 1981 use(ln->u.value.u.integer != 0 1982 ? rn->u.ops.right : rn->u.ops.left); 1983 ntn = ln->u.value.u.integer != 0 1984 ? rn->u.ops.left : rn->u.ops.right; 1985 } 1986 } 1987 1988 return ntn; 1989 } 1990 1991 tnode_t * 1992 build_unary(op_t op, bool sys, tnode_t *tn) 1993 { 1994 return build_binary(tn, op, sys, NULL); 1995 } 1996 1997 static bool 1998 are_members_compatible(const sym_t *a, const sym_t *b) 1999 { 2000 if (a->u.s_member.sm_offset_in_bits != b->u.s_member.sm_offset_in_bits) 2001 return false; 2002 2003 const type_t *atp = a->s_type; 2004 const type_t *btp = b->s_type; 2005 bool w = false; 2006 if (!types_compatible(atp, btp, false, false, &w) && !w) 2007 return false; 2008 if (a->s_bitfield != b->s_bitfield) 2009 return false; 2010 if (a->s_bitfield) { 2011 if (atp->t_bit_field_width != btp->t_bit_field_width) 2012 return false; 2013 if (atp->t_bit_field_offset != btp->t_bit_field_offset) 2014 return false; 2015 } 2016 return true; 2017 } 2018 2019 /* 2020 * Return whether all struct/union members with the same name have the same 2021 * type and offset. 2022 */ 2023 static bool 2024 all_members_compatible(const sym_t *msym) 2025 { 2026 for (const sym_t *csym = msym; 2027 csym != NULL; csym = csym->s_symtab_next) { 2028 if (!is_member(csym)) 2029 continue; 2030 if (strcmp(msym->s_name, csym->s_name) != 0) 2031 continue; 2032 2033 for (const sym_t *sym = csym->s_symtab_next; 2034 sym != NULL; sym = sym->s_symtab_next) { 2035 if (is_member(sym) 2036 && strcmp(csym->s_name, sym->s_name) == 0 2037 && !are_members_compatible(csym, sym)) 2038 return false; 2039 } 2040 } 2041 return true; 2042 } 2043 2044 sym_t * 2045 find_member(const struct_or_union *sou, const char *name) 2046 { 2047 for (sym_t *mem = sou->sou_first_member; 2048 mem != NULL; mem = mem->s_next) { 2049 lint_assert(is_member(mem)); 2050 lint_assert(mem->u.s_member.sm_containing_type == sou); 2051 if (strcmp(mem->s_name, name) == 0) 2052 return mem; 2053 } 2054 2055 for (sym_t *mem = sou->sou_first_member; 2056 mem != NULL; mem = mem->s_next) { 2057 if (is_struct_or_union(mem->s_type->t_tspec) 2058 && mem->s_name == unnamed) { 2059 sym_t *nested_mem = 2060 find_member(mem->s_type->u.sou, name); 2061 if (nested_mem != NULL) 2062 return nested_mem; 2063 } 2064 } 2065 return NULL; 2066 } 2067 2068 /* 2069 * Remove the member if it was unknown until now, which means 2070 * that no defined struct or union has a member with the same name. 2071 */ 2072 static void 2073 remove_unknown_member(tnode_t *tn, sym_t *msym) 2074 { 2075 /* type '%s' does not have member '%s' */ 2076 error(101, type_name(tn->tn_type), msym->s_name); 2077 symtab_remove_forever(msym); 2078 msym->s_kind = SK_MEMBER; 2079 msym->s_scl = STRUCT_MEMBER; 2080 2081 struct_or_union *sou = expr_zero_alloc(sizeof(*sou), 2082 "struct_or_union"); 2083 sou->sou_tag = expr_zero_alloc(sizeof(*sou->sou_tag), "sym"); 2084 sou->sou_tag->s_name = unnamed; 2085 2086 msym->u.s_member.sm_containing_type = sou; 2087 /* 2088 * The member sm_offset_in_bits is not needed here since this symbol 2089 * can only be used for error reporting. 2090 */ 2091 } 2092 2093 /* 2094 * Returns a symbol which has the same name as 'msym' and is a member of the 2095 * struct or union specified by 'tn'. 2096 */ 2097 static sym_t * 2098 struct_or_union_member(tnode_t *tn, op_t op, sym_t *msym) 2099 { 2100 2101 /* Determine the tag type of which msym is expected to be a member. */ 2102 const type_t *tp = NULL; 2103 if (op == POINT && is_struct_or_union(tn->tn_type->t_tspec)) 2104 tp = tn->tn_type; 2105 if (op == ARROW && tn->tn_type->t_tspec == PTR 2106 && is_struct_or_union(tn->tn_type->t_subt->t_tspec)) 2107 tp = tn->tn_type->t_subt; 2108 struct_or_union *sou = tp != NULL ? tp->u.sou : NULL; 2109 2110 if (sou != NULL) { 2111 sym_t *nested_mem = find_member(sou, msym->s_name); 2112 if (nested_mem != NULL) 2113 return nested_mem; 2114 } 2115 2116 if (msym->s_scl == NO_SCL) { 2117 remove_unknown_member(tn, msym); 2118 return msym; 2119 } 2120 2121 bool eq = all_members_compatible(msym); 2122 2123 /* 2124 * Now handle the case in which the left operand refers really to a 2125 * struct/union, but the right operand is not member of it. 2126 */ 2127 if (sou != NULL) { 2128 if (eq && !allow_c90) 2129 /* illegal use of member '%s' */ 2130 warning(102, msym->s_name); 2131 else 2132 /* illegal use of member '%s' */ 2133 error(102, msym->s_name); 2134 return msym; 2135 } 2136 2137 if (eq) { 2138 if (op == POINT) { 2139 if (!allow_c90) 2140 /* left operand of '.' must be struct ... */ 2141 warning(103, type_name(tn->tn_type)); 2142 else 2143 /* left operand of '.' must be struct ... */ 2144 error(103, type_name(tn->tn_type)); 2145 } else { 2146 if (!allow_c90 && tn->tn_type->t_tspec == PTR) 2147 /* left operand of '->' must be pointer ... */ 2148 warning(104, type_name(tn->tn_type)); 2149 else 2150 /* left operand of '->' must be pointer ... */ 2151 error(104, type_name(tn->tn_type)); 2152 } 2153 } else { 2154 if (!allow_c90) 2155 /* non-unique member requires struct/union %s */ 2156 error(105, op == POINT ? "object" : "pointer"); 2157 else 2158 /* unacceptable operand of '%s' */ 2159 error(111, op_name(op)); 2160 } 2161 2162 return msym; 2163 } 2164 2165 tnode_t * 2166 build_member_access(tnode_t *ln, op_t op, bool sys, sbuf_t *member) 2167 { 2168 sym_t *msym; 2169 2170 if (ln == NULL) 2171 return NULL; 2172 2173 if (op == ARROW) 2174 /* must do this before struct_or_union_member is called */ 2175 ln = cconv(ln); 2176 msym = struct_or_union_member(ln, op, getsym(member)); 2177 return build_binary(ln, op, sys, build_name(msym, false)); 2178 } 2179 2180 /* 2181 * Perform class conversions. 2182 * 2183 * Arrays of type T are converted into pointers to type T. 2184 * Functions are converted to pointers to functions. 2185 * Lvalues are converted to rvalues. 2186 * 2187 * C99 6.3 "Conversions" 2188 * C99 6.3.2 "Other operands" 2189 * C99 6.3.2.1 "Lvalues, arrays, and function designators" 2190 */ 2191 tnode_t * 2192 cconv(tnode_t *tn) 2193 { 2194 if (tn->tn_type->t_tspec == ARRAY) { 2195 if (!tn->tn_lvalue) { 2196 /* XXX print correct operator */ 2197 /* %soperand of '%s' must be lvalue */ 2198 gnuism(114, "", op_name(ADDR)); 2199 } 2200 tn = build_op(ADDR, tn->tn_sys, 2201 expr_derive_type(tn->tn_type->t_subt, PTR), tn, NULL); 2202 } 2203 2204 if (tn->tn_type->t_tspec == FUNC) 2205 tn = build_address(tn->tn_sys, tn, true); 2206 2207 if (tn->tn_lvalue) { 2208 type_t *tp = expr_dup_type(tn->tn_type); 2209 /* C99 6.3.2.1p2 sentence 2 says to remove the qualifiers. */ 2210 tp->t_const = tp->t_volatile = false; 2211 tn = build_op(LOAD, tn->tn_sys, tp, tn, NULL); 2212 } 2213 2214 return tn; 2215 } 2216 2217 const tnode_t * 2218 before_conversion(const tnode_t *tn) 2219 { 2220 while (tn->tn_op == CVT && !tn->tn_cast) 2221 tn = tn->u.ops.left; 2222 return tn; 2223 } 2224 2225 /* 2226 * Most errors required by C90 are reported in struct_or_union_member(). 2227 * Here we only check for totally wrong things. 2228 */ 2229 static bool 2230 typeok_point(const tnode_t *ln, const type_t *ltp, tspec_t lt) 2231 { 2232 if (is_struct_or_union(lt)) 2233 return true; 2234 2235 if (lt == FUNC || lt == VOID || ltp->t_bitfield) 2236 goto wrong; 2237 2238 /* 2239 * Some C dialects from before C90 tolerated any lvalue on the 2240 * left-hand side of the '.' operator, allowing things like 'char 2241 * st[100]; st.st_mtime', assuming that the member 'st_mtime' only 2242 * occurred in a single struct; see typeok_arrow. 2243 */ 2244 if (ln->tn_lvalue) 2245 return true; 2246 2247 wrong: 2248 /* With allow_c90 we already got an error */ 2249 if (!allow_c90) 2250 /* unacceptable operand of '%s' */ 2251 error(111, op_name(POINT)); 2252 2253 return false; 2254 } 2255 2256 static bool 2257 typeok_arrow(tspec_t lt) 2258 { 2259 /* 2260 * C1978 Appendix A 14.1 says: <quote>In fact, any lvalue is allowed 2261 * before '.', and that lvalue is then assumed to have the form of the 2262 * structure of which the name of the right is a member. [...] Such 2263 * constructions are non-portable.</quote> 2264 */ 2265 if (lt == PTR || (!allow_c90 && is_integer(lt))) 2266 return true; 2267 2268 /* With allow_c90 we already got an error */ 2269 if (!allow_c90) 2270 /* unacceptable operand of '%s' */ 2271 error(111, op_name(ARROW)); 2272 return false; 2273 } 2274 2275 static bool 2276 typeok_incdec(op_t op, const tnode_t *tn, const type_t *tp) 2277 { 2278 /* operand has scalar type (checked in typeok) */ 2279 if (!tn->tn_lvalue) { 2280 if (tn->tn_op == CVT && tn->tn_cast && 2281 tn->u.ops.left->tn_op == LOAD) 2282 /* a cast does not yield an lvalue */ 2283 error(163); 2284 /* %soperand of '%s' must be lvalue */ 2285 error(114, "", op_name(op)); 2286 return false; 2287 } 2288 if (tp->t_const && allow_c90) 2289 /* %soperand of '%s' must be modifiable lvalue */ 2290 warning(115, "", op_name(op)); 2291 return true; 2292 } 2293 2294 static bool 2295 typeok_address(op_t op, const tnode_t *tn, const type_t *tp, tspec_t t) 2296 { 2297 if (t == ARRAY || t == FUNC) { 2298 /* ok, a warning comes later (in build_address()) */ 2299 } else if (!tn->tn_lvalue) { 2300 if (tn->tn_op == CVT && tn->tn_cast && 2301 tn->u.ops.left->tn_op == LOAD) 2302 /* a cast does not yield an lvalue */ 2303 error(163); 2304 /* %soperand of '%s' must be lvalue */ 2305 error(114, "", op_name(op)); 2306 return false; 2307 } else if (is_scalar(t)) { 2308 if (tp->t_bitfield) { 2309 /* cannot take address of bit-field */ 2310 error(112); 2311 return false; 2312 } 2313 } else if (t != STRUCT && t != UNION) { 2314 /* unacceptable operand of '%s' */ 2315 error(111, op_name(op)); 2316 return false; 2317 } 2318 if (tn->tn_op == NAME && tn->u.sym->s_register) { 2319 /* cannot take address of register '%s' */ 2320 error(113, tn->u.sym->s_name); 2321 return false; 2322 } 2323 return true; 2324 } 2325 2326 static bool 2327 typeok_indir(const type_t *tp, tspec_t t) 2328 { 2329 2330 if (t != PTR) { 2331 /* cannot dereference non-pointer type '%s' */ 2332 error(96, type_name(tp)); 2333 return false; 2334 } 2335 return true; 2336 } 2337 2338 static void 2339 warn_incompatible_types(op_t op, 2340 const type_t *ltp, tspec_t lt, 2341 const type_t *rtp, tspec_t rt) 2342 { 2343 bool binary = modtab[op].m_binary; 2344 2345 if (lt == VOID || (binary && rt == VOID)) { 2346 /* void type illegal in expression */ 2347 error(109); 2348 } else if (op == ASSIGN) 2349 /* cannot assign to '%s' from '%s' */ 2350 error(171, type_name(ltp), type_name(rtp)); 2351 else if (binary) 2352 /* operands of '%s' have incompatible types '%s' and '%s' */ 2353 error(107, op_name(op), type_name(ltp), type_name(rtp)); 2354 else { 2355 lint_assert(rt == NO_TSPEC); 2356 /* operand of '%s' has invalid type '%s' */ 2357 error(108, op_name(op), type_name(ltp)); 2358 } 2359 } 2360 2361 static bool 2362 typeok_plus(op_t op, 2363 const type_t *ltp, tspec_t lt, 2364 const type_t *rtp, tspec_t rt) 2365 { 2366 /* operands have scalar types (checked in typeok) */ 2367 if ((lt == PTR && !is_integer(rt)) || (rt == PTR && !is_integer(lt))) { 2368 warn_incompatible_types(op, ltp, lt, rtp, rt); 2369 return false; 2370 } 2371 return true; 2372 } 2373 2374 static bool 2375 typeok_minus(op_t op, 2376 const type_t *ltp, tspec_t lt, 2377 const type_t *rtp, tspec_t rt) 2378 { 2379 /* operands have scalar types (checked in typeok) */ 2380 if ((lt == PTR && rt != PTR && !is_integer(rt)) || 2381 (lt != PTR && rt == PTR)) { 2382 warn_incompatible_types(op, ltp, lt, rtp, rt); 2383 return false; 2384 } 2385 if (lt == PTR && rt == PTR && 2386 !types_compatible(ltp->t_subt, rtp->t_subt, true, false, NULL)) { 2387 /* illegal pointer subtraction */ 2388 error(116); 2389 } 2390 return true; 2391 } 2392 2393 static void 2394 typeok_shr(op_t op, 2395 const tnode_t *ln, tspec_t lt, 2396 const tnode_t *rn, tspec_t rt) 2397 { 2398 tspec_t olt = before_conversion(ln)->tn_type->t_tspec; 2399 tspec_t ort = before_conversion(rn)->tn_type->t_tspec; 2400 2401 /* operands have integer types (checked in typeok) */ 2402 if (pflag && !is_uinteger(olt)) { 2403 integer_constraints lc = ic_expr(ln); 2404 if (!ic_maybe_signed(ln->tn_type, &lc)) 2405 return; 2406 2407 if (ln->tn_op != CON) 2408 /* bitwise '%s' on signed value possibly nonportable */ 2409 warning(117, op_name(op)); 2410 else if (ln->u.value.u.integer < 0) 2411 /* bitwise '%s' on signed value nonportable */ 2412 warning(120, op_name(op)); 2413 } else if (allow_trad && allow_c90 && 2414 !is_uinteger(olt) && is_uinteger(ort)) { 2415 /* The left operand would become unsigned in traditional C. */ 2416 if (hflag && (ln->tn_op != CON || ln->u.value.u.integer < 0)) { 2417 /* semantics of '%s' change in C90; use ... */ 2418 warning(118, op_name(op)); 2419 } 2420 } else if (allow_trad && allow_c90 && 2421 !is_uinteger(olt) && !is_uinteger(ort) && 2422 portable_rank_cmp(lt, rt) < 0) { 2423 /* 2424 * In traditional C, the left operand would be extended 2425 * (possibly sign-extended) and then shifted. 2426 */ 2427 if (hflag && (ln->tn_op != CON || ln->u.value.u.integer < 0)) { 2428 /* semantics of '%s' change in C90; use ... */ 2429 warning(118, op_name(op)); 2430 } 2431 } 2432 } 2433 2434 static void 2435 typeok_shl(op_t op, tspec_t lt, tspec_t rt) 2436 { 2437 /* 2438 * C90 does not perform balancing for shift operations, but traditional 2439 * C does. If the width of the right operand is greater than the width 2440 * of the left operand, then in traditional C the left operand would be 2441 * extended to the width of the right operand. For SHL this may result 2442 * in different results. 2443 */ 2444 if (portable_rank_cmp(lt, rt) < 0) { 2445 /* 2446 * XXX If both operands are constant, make sure that there is 2447 * really a difference between C90 and traditional C. 2448 */ 2449 if (hflag && allow_trad && allow_c90) 2450 /* semantics of '%s' change in C90; use ... */ 2451 warning(118, op_name(op)); 2452 } 2453 } 2454 2455 static void 2456 typeok_shift(const type_t *ltp, tspec_t lt, const tnode_t *rn, tspec_t rt) 2457 { 2458 if (rn->tn_op != CON) 2459 return; 2460 2461 if (!is_uinteger(rt) && rn->u.value.u.integer < 0) 2462 /* negative shift */ 2463 warning(121); 2464 else if ((uint64_t)rn->u.value.u.integer == size_in_bits(lt)) 2465 /* shift amount %u equals bit-size of '%s' */ 2466 warning(267, (unsigned)rn->u.value.u.integer, type_name(ltp)); 2467 else if ((uint64_t)rn->u.value.u.integer > size_in_bits(lt)) { 2468 /* shift amount %llu is greater than bit-size %llu of '%s' */ 2469 warning(122, (unsigned long long)rn->u.value.u.integer, 2470 (unsigned long long)size_in_bits(lt), 2471 tspec_name(lt)); 2472 } 2473 } 2474 2475 static bool 2476 is_typeok_eq(const tnode_t *ln, tspec_t lt, const tnode_t *rn, tspec_t rt) 2477 { 2478 if (lt == PTR && is_null_pointer(rn)) 2479 return true; 2480 if (rt == PTR && is_null_pointer(ln)) 2481 return true; 2482 return false; 2483 } 2484 2485 static void 2486 warn_incompatible_pointers(op_t op, const type_t *ltp, const type_t *rtp) 2487 { 2488 lint_assert(ltp->t_tspec == PTR); 2489 lint_assert(rtp->t_tspec == PTR); 2490 2491 tspec_t lt = ltp->t_subt->t_tspec; 2492 tspec_t rt = rtp->t_subt->t_tspec; 2493 2494 if (is_struct_or_union(lt) && is_struct_or_union(rt)) { 2495 if (op == RETURN) 2496 /* illegal structure pointer combination */ 2497 warning(244); 2498 else { 2499 /* incompatible structure pointers: '%s' '%s' '%s' */ 2500 warning(245, type_name(ltp), 2501 op_name(op), type_name(rtp)); 2502 } 2503 } else { 2504 if (op == RETURN) 2505 /* illegal combination of '%s' and '%s' */ 2506 warning(184, type_name(ltp), type_name(rtp)); 2507 else { 2508 /* illegal combination of '%s' and '%s', op '%s' */ 2509 warning(124, 2510 type_name(ltp), type_name(rtp), op_name(op)); 2511 } 2512 } 2513 } 2514 2515 static void 2516 check_pointer_comparison(op_t op, const tnode_t *ln, const tnode_t *rn) 2517 { 2518 type_t *ltp = ln->tn_type, *rtp = rn->tn_type; 2519 tspec_t lst = ltp->t_subt->t_tspec, rst = rtp->t_subt->t_tspec; 2520 2521 if (lst == VOID || rst == VOID) { 2522 /* TODO: C99 behaves like C90 here. */ 2523 if (!allow_trad && !allow_c99 && 2524 (lst == FUNC || rst == FUNC)) { 2525 /* (void *)0 is already handled in typeok() */ 2526 const char *lsts, *rsts; 2527 *(lst == FUNC ? &lsts : &rsts) = "function pointer"; 2528 *(lst == VOID ? &lsts : &rsts) = "'void *'"; 2529 /* C90 or later forbid comparison of %s with %s */ 2530 warning(274, lsts, rsts); 2531 } 2532 return; 2533 } 2534 2535 if (!types_compatible(ltp->t_subt, rtp->t_subt, true, false, NULL)) { 2536 warn_incompatible_pointers(op, ltp, rtp); 2537 return; 2538 } 2539 2540 if (lst == FUNC && rst == FUNC) { 2541 /* TODO: C99 behaves like C90 here, see C99 6.5.8p2. */ 2542 if (!allow_trad && !allow_c99 && op != EQ && op != NE) 2543 /* pointers to functions can only be compared ... */ 2544 warning(125); 2545 } 2546 } 2547 2548 static bool 2549 typeok_compare(op_t op, 2550 const tnode_t *ln, const type_t *ltp, tspec_t lt, 2551 const tnode_t *rn, const type_t *rtp, tspec_t rt) 2552 { 2553 if (lt == PTR && rt == PTR) { 2554 check_pointer_comparison(op, ln, rn); 2555 return true; 2556 } 2557 2558 if (lt != PTR && rt != PTR) 2559 return true; 2560 2561 if (!is_integer(lt) && !is_integer(rt)) { 2562 warn_incompatible_types(op, ltp, lt, rtp, rt); 2563 return false; 2564 } 2565 2566 const char *lx = lt == PTR ? "pointer" : "integer"; 2567 const char *rx = rt == PTR ? "pointer" : "integer"; 2568 /* illegal combination of %s '%s' and %s '%s', op '%s' */ 2569 warning(123, lx, type_name(ltp), rx, type_name(rtp), op_name(op)); 2570 return true; 2571 } 2572 2573 static bool 2574 typeok_quest(tspec_t lt, const tnode_t *rn) 2575 { 2576 if (!is_scalar(lt)) { 2577 /* first operand of '?' must have scalar type */ 2578 error(170); 2579 return false; 2580 } 2581 lint_assert(before_conversion(rn)->tn_op == COLON); 2582 return true; 2583 } 2584 2585 static void 2586 typeok_colon_pointer(const type_t *ltp, const type_t *rtp) 2587 { 2588 type_t *lstp = ltp->t_subt; 2589 type_t *rstp = rtp->t_subt; 2590 tspec_t lst = lstp->t_tspec; 2591 tspec_t rst = rstp->t_tspec; 2592 2593 if ((lst == VOID && rst == FUNC) || (lst == FUNC && rst == VOID)) { 2594 /* (void *)0 is handled in typeok_colon */ 2595 /* TODO: C99 behaves like C90 here. */ 2596 if (!allow_trad && !allow_c99) 2597 /* conversion of %s to %s requires a cast, op %s */ 2598 warning(305, "function pointer", "'void *'", 2599 op_name(COLON)); 2600 return; 2601 } 2602 2603 if (pointer_types_are_compatible(lstp, rstp, true)) 2604 return; 2605 if (!types_compatible(lstp, rstp, true, false, NULL)) 2606 warn_incompatible_pointers(COLON, ltp, rtp); 2607 } 2608 2609 static bool 2610 typeok_colon(const tnode_t *ln, const type_t *ltp, tspec_t lt, 2611 const tnode_t *rn, const type_t *rtp, tspec_t rt) 2612 { 2613 2614 if (is_arithmetic(lt) && is_arithmetic(rt)) 2615 return true; 2616 if (lt == BOOL && rt == BOOL) 2617 return true; 2618 2619 if (lt == STRUCT && rt == STRUCT && ltp->u.sou == rtp->u.sou) 2620 return true; 2621 if (lt == UNION && rt == UNION && ltp->u.sou == rtp->u.sou) 2622 return true; 2623 2624 if (lt == PTR && is_null_pointer(rn)) 2625 return true; 2626 if (rt == PTR && is_null_pointer(ln)) 2627 return true; 2628 2629 if ((lt == PTR && is_integer(rt)) || (is_integer(lt) && rt == PTR)) { 2630 const char *lx = lt == PTR ? "pointer" : "integer"; 2631 const char *rx = rt == PTR ? "pointer" : "integer"; 2632 /* illegal combination of %s '%s' and %s '%s', op '%s' */ 2633 warning(123, lx, type_name(ltp), 2634 rx, type_name(rtp), op_name(COLON)); 2635 return true; 2636 } 2637 2638 if (lt == VOID || rt == VOID) { 2639 if (lt != VOID || rt != VOID) 2640 /* incompatible types '%s' and '%s' in conditional */ 2641 warning(126, type_name(ltp), type_name(rtp)); 2642 return true; 2643 } 2644 2645 if (lt == PTR && rt == PTR) { 2646 typeok_colon_pointer(ltp, rtp); 2647 return true; 2648 } 2649 2650 /* incompatible types '%s' and '%s' in conditional */ 2651 error(126, type_name(ltp), type_name(rtp)); 2652 return false; 2653 } 2654 2655 static bool 2656 has_constant_member(const type_t *tp) 2657 { 2658 lint_assert(is_struct_or_union(tp->t_tspec)); 2659 2660 for (sym_t *m = tp->u.sou->sou_first_member; 2661 m != NULL; m = m->s_next) { 2662 const type_t *mtp = m->s_type; 2663 if (mtp->t_const) 2664 return true; 2665 if (is_struct_or_union(mtp->t_tspec) && 2666 has_constant_member(mtp)) 2667 return true; 2668 } 2669 return false; 2670 } 2671 2672 static bool 2673 typeok_assign(op_t op, const tnode_t *ln, const type_t *ltp, tspec_t lt) 2674 { 2675 if (op == RETURN || op == INIT || op == FARG) 2676 return true; 2677 2678 if (!ln->tn_lvalue) { 2679 if (ln->tn_op == CVT && ln->tn_cast && 2680 ln->u.ops.left->tn_op == LOAD) 2681 /* a cast does not yield an lvalue */ 2682 error(163); 2683 /* %soperand of '%s' must be lvalue */ 2684 error(114, "left ", op_name(op)); 2685 return false; 2686 } else if (ltp->t_const 2687 || (is_struct_or_union(lt) && has_constant_member(ltp))) { 2688 if (allow_c90) 2689 /* %soperand of '%s' must be modifiable lvalue */ 2690 warning(115, "left ", op_name(op)); 2691 } 2692 return true; 2693 } 2694 2695 static bool 2696 typeok_scalar(op_t op, const mod_t *mp, 2697 const type_t *ltp, tspec_t lt, 2698 const type_t *rtp, tspec_t rt) 2699 { 2700 if (mp->m_takes_bool && lt == BOOL && rt == BOOL) 2701 return true; 2702 if (mp->m_requires_integer) { 2703 if (!is_integer(lt) || (mp->m_binary && !is_integer(rt))) { 2704 warn_incompatible_types(op, ltp, lt, rtp, rt); 2705 return false; 2706 } 2707 } else if (mp->m_requires_integer_or_complex) { 2708 if ((!is_integer(lt) && !is_complex(lt)) || 2709 (mp->m_binary && (!is_integer(rt) && !is_complex(rt)))) { 2710 warn_incompatible_types(op, ltp, lt, rtp, rt); 2711 return false; 2712 } 2713 } else if (mp->m_requires_scalar) { 2714 if (!is_scalar(lt) || (mp->m_binary && !is_scalar(rt))) { 2715 warn_incompatible_types(op, ltp, lt, rtp, rt); 2716 return false; 2717 } 2718 } else if (mp->m_requires_arith) { 2719 if (!is_arithmetic(lt) || 2720 (mp->m_binary && !is_arithmetic(rt))) { 2721 warn_incompatible_types(op, ltp, lt, rtp, rt); 2722 return false; 2723 } 2724 } 2725 return true; 2726 } 2727 2728 static void 2729 check_assign_void_pointer(op_t op, int arg, 2730 tspec_t lt, tspec_t lst, 2731 tspec_t rt, tspec_t rst) 2732 { 2733 2734 if (!(lt == PTR && rt == PTR && (lst == VOID || rst == VOID))) 2735 return; 2736 /* two pointers, at least one pointer to void */ 2737 2738 /* TODO: C99 behaves like C90 here. */ 2739 if (!(!allow_trad && !allow_c99 && (lst == FUNC || rst == FUNC))) 2740 return; 2741 /* comb. of ptr to func and ptr to void */ 2742 2743 const char *lts, *rts; 2744 *(lst == FUNC ? <s : &rts) = "function pointer"; 2745 *(lst == VOID ? <s : &rts) = "'void *'"; 2746 2747 switch (op) { 2748 case INIT: 2749 case RETURN: 2750 /* conversion of %s to %s requires a cast */ 2751 warning(303, rts, lts); 2752 break; 2753 case FARG: 2754 /* conversion of %s to %s requires a cast, arg #%d */ 2755 warning(304, rts, lts, arg); 2756 break; 2757 default: 2758 /* conversion of %s to %s requires a cast, op %s */ 2759 warning(305, rts, lts, op_name(op)); 2760 break; 2761 } 2762 } 2763 2764 static bool 2765 is_direct_function_call(const tnode_t *tn, const char **out_name) 2766 { 2767 2768 if (tn->tn_op == CALL 2769 && tn->u.call->func->tn_op == ADDR 2770 && tn->u.call->func->u.ops.left->tn_op == NAME) { 2771 *out_name = tn->u.call->func->u.ops.left->u.sym->s_name; 2772 return true; 2773 } 2774 return false; 2775 } 2776 2777 static bool 2778 is_unconst_function(const char *name) 2779 { 2780 2781 return strcmp(name, "memchr") == 0 || 2782 strcmp(name, "strchr") == 0 || 2783 strcmp(name, "strpbrk") == 0 || 2784 strcmp(name, "strrchr") == 0 || 2785 strcmp(name, "strstr") == 0; 2786 } 2787 2788 static bool 2789 is_const_char_pointer(const tnode_t *tn) 2790 { 2791 /* 2792 * For traditional reasons, C99 6.4.5p5 defines that string literals 2793 * have type 'char[]'. They are often implicitly converted to 'char 2794 * *', for example when they are passed as function arguments. 2795 * 2796 * C99 6.4.5p6 further defines that modifying a string that is 2797 * constructed from a string literal invokes undefined behavior. 2798 * 2799 * Out of these reasons, string literals are treated as 'effectively 2800 * const' here. 2801 */ 2802 if (tn->tn_op == CVT && 2803 tn->u.ops.left->tn_op == ADDR && 2804 tn->u.ops.left->u.ops.left->tn_op == STRING) 2805 return true; 2806 2807 const type_t *tp = before_conversion(tn)->tn_type; 2808 return tp->t_tspec == PTR && 2809 tp->t_subt->t_tspec == CHAR && 2810 tp->t_subt->t_const; 2811 } 2812 2813 static bool 2814 is_const_pointer(const tnode_t *tn) 2815 { 2816 const type_t *tp = before_conversion(tn)->tn_type; 2817 return tp->t_tspec == PTR && tp->t_subt->t_const; 2818 } 2819 2820 static void 2821 check_unconst_function(const type_t *lstp, const tnode_t *rn) 2822 { 2823 const char *function_name; 2824 2825 if (lstp->t_tspec == CHAR && !lstp->t_const && 2826 is_direct_function_call(rn, &function_name) && 2827 is_unconst_function(function_name) && 2828 rn->u.call->args_len >= 1 && 2829 is_const_char_pointer(rn->u.call->args[0])) { 2830 /* call to '%s' effectively discards 'const' from argument */ 2831 warning(346, function_name); 2832 } 2833 2834 if (!lstp->t_const && 2835 is_direct_function_call(rn, &function_name) && 2836 strcmp(function_name, "bsearch") == 0 && 2837 rn->u.call->args_len >= 2 && 2838 is_const_pointer(rn->u.call->args[1])) { 2839 /* call to '%s' effectively discards 'const' from argument */ 2840 warning(346, function_name); 2841 } 2842 } 2843 2844 static bool 2845 check_assign_void_pointer_compat(op_t op, int arg, 2846 const type_t *ltp, tspec_t lt, 2847 const type_t *lstp, tspec_t lst, 2848 const tnode_t *rn, 2849 const type_t *rtp, tspec_t rt, 2850 const type_t *rstp, tspec_t rst) 2851 { 2852 if (!(lt == PTR && rt == PTR && (lst == VOID || rst == VOID || 2853 types_compatible(lstp, rstp, 2854 true, false, NULL)))) 2855 return false; 2856 2857 /* compatible pointer types (qualifiers ignored) */ 2858 if (allow_c90 && 2859 ((!lstp->t_const && rstp->t_const) || 2860 (!lstp->t_volatile && rstp->t_volatile))) { 2861 /* left side has not all qualifiers of right */ 2862 switch (op) { 2863 case INIT: 2864 case RETURN: 2865 /* incompatible pointer types to '%s' and '%s' */ 2866 warning(182, type_name(lstp), type_name(rstp)); 2867 break; 2868 case FARG: 2869 /* converting '%s' to incompatible '%s' ... */ 2870 warning(153, 2871 type_name(rtp), type_name(ltp), arg); 2872 break; 2873 default: 2874 /* operands of '%s' have incompatible pointer ... */ 2875 warning(128, op_name(op), 2876 type_name(lstp), type_name(rstp)); 2877 break; 2878 } 2879 } 2880 2881 if (allow_c90) 2882 check_unconst_function(lstp, rn); 2883 2884 return true; 2885 } 2886 2887 static bool 2888 check_assign_pointer_integer(op_t op, int arg, 2889 const type_t *ltp, tspec_t lt, 2890 const type_t *rtp, tspec_t rt) 2891 { 2892 2893 if (!((lt == PTR && is_integer(rt)) || (is_integer(lt) && rt == PTR))) 2894 return false; 2895 2896 const char *lx = lt == PTR ? "pointer" : "integer"; 2897 const char *rx = rt == PTR ? "pointer" : "integer"; 2898 2899 switch (op) { 2900 case INIT: 2901 case RETURN: 2902 /* illegal combination of %s '%s' and %s '%s' */ 2903 warning(183, lx, type_name(ltp), rx, type_name(rtp)); 2904 break; 2905 case FARG: 2906 /* illegal combination of %s '%s' and %s '%s', arg #%d */ 2907 warning(154, 2908 lx, type_name(ltp), rx, type_name(rtp), arg); 2909 break; 2910 default: 2911 /* illegal combination of %s '%s' and %s '%s', op '%s' */ 2912 warning(123, 2913 lx, type_name(ltp), rx, type_name(rtp), op_name(op)); 2914 break; 2915 } 2916 return true; 2917 } 2918 2919 static bool 2920 check_assign_pointer(op_t op, int arg, 2921 const type_t *ltp, tspec_t lt, 2922 const type_t *rtp, tspec_t rt) 2923 { 2924 if (!(lt == PTR && rt == PTR)) 2925 return false; 2926 2927 if (op == FARG) 2928 /* converting '%s' to incompatible '%s' for ... */ 2929 warning(153, type_name(rtp), type_name(ltp), arg); 2930 else 2931 warn_incompatible_pointers(op, ltp, rtp); 2932 return true; 2933 } 2934 2935 static void 2936 warn_assign(op_t op, int arg, 2937 const type_t *ltp, tspec_t lt, 2938 const type_t *rtp, tspec_t rt) 2939 { 2940 switch (op) { 2941 case INIT: 2942 /* cannot initialize '%s' from '%s' */ 2943 error(185, type_name(ltp), type_name(rtp)); 2944 break; 2945 case RETURN: 2946 /* function has return type '%s' but returns '%s' */ 2947 error(211, type_name(ltp), type_name(rtp)); 2948 break; 2949 case FARG: 2950 /* passing '%s' to incompatible '%s', arg #%d */ 2951 warning(155, type_name(rtp), type_name(ltp), arg); 2952 break; 2953 default: 2954 warn_incompatible_types(op, ltp, lt, rtp, rt); 2955 break; 2956 } 2957 } 2958 2959 /* 2960 * Checks type compatibility for ASSIGN, INIT, FARG and RETURN 2961 * and prints warnings/errors if necessary. 2962 * Returns whether the types are (almost) compatible. 2963 */ 2964 static bool 2965 check_assign_types_compatible(op_t op, int arg, 2966 const tnode_t *ln, const tnode_t *rn) 2967 { 2968 tspec_t lt, rt, lst = NO_TSPEC, rst = NO_TSPEC; 2969 type_t *ltp, *rtp, *lstp = NULL, *rstp = NULL; 2970 2971 if ((lt = (ltp = ln->tn_type)->t_tspec) == PTR) 2972 lst = (lstp = ltp->t_subt)->t_tspec; 2973 if ((rt = (rtp = rn->tn_type)->t_tspec) == PTR) 2974 rst = (rstp = rtp->t_subt)->t_tspec; 2975 2976 if (lt == BOOL && is_scalar(rt)) /* C99 6.3.1.2 */ 2977 return true; 2978 2979 if (is_arithmetic(lt) && (is_arithmetic(rt) || rt == BOOL)) 2980 return true; 2981 2982 if (is_struct_or_union(lt) && is_struct_or_union(rt)) 2983 return ltp->u.sou == rtp->u.sou; 2984 2985 if (lt == PTR && is_null_pointer(rn)) { 2986 if (is_integer(rn->tn_type->t_tspec)) 2987 /* implicit conversion from integer 0 to pointer ... */ 2988 query_message(15, type_name(ltp)); 2989 return true; 2990 } 2991 2992 check_assign_void_pointer(op, arg, lt, lst, rt, rst); 2993 2994 if (check_assign_void_pointer_compat(op, arg, 2995 ltp, lt, lstp, lst, rn, rtp, rt, rstp, rst)) 2996 return true; 2997 2998 if (check_assign_pointer_integer(op, arg, ltp, lt, rtp, rt)) 2999 return true; 3000 3001 if (check_assign_pointer(op, arg, ltp, lt, rtp, rt)) 3002 return true; 3003 3004 warn_assign(op, arg, ltp, lt, rtp, rt); 3005 return false; 3006 } 3007 3008 static bool 3009 has_side_effect(const tnode_t *tn) /* NOLINT(misc-no-recursion) */ 3010 { 3011 op_t op = tn->tn_op; 3012 3013 if (modtab[op].m_has_side_effect) 3014 return true; 3015 3016 if (op == CVT && tn->tn_type->t_tspec == VOID) 3017 return has_side_effect(tn->u.ops.left); 3018 3019 /* XXX: Why not has_side_effect(tn->u.ops.left) as well? */ 3020 if (op == LOGAND || op == LOGOR) 3021 return has_side_effect(tn->u.ops.right); 3022 3023 /* XXX: Why not has_side_effect(tn->u.ops.left) as well? */ 3024 if (op == QUEST) 3025 return has_side_effect(tn->u.ops.right); 3026 3027 if (op == COLON || op == COMMA) { 3028 return has_side_effect(tn->u.ops.left) || 3029 has_side_effect(tn->u.ops.right); 3030 } 3031 3032 return false; 3033 } 3034 3035 static bool 3036 is_void_cast(const tnode_t *tn) 3037 { 3038 3039 return tn->tn_op == CVT && tn->tn_cast && 3040 tn->tn_type->t_tspec == VOID; 3041 } 3042 3043 static bool 3044 is_local_symbol(const tnode_t *tn) 3045 { 3046 3047 return tn->tn_op == LOAD && 3048 tn->u.ops.left->tn_op == NAME && 3049 tn->u.ops.left->u.sym->s_scl == AUTO; 3050 } 3051 3052 static bool 3053 is_int_constant_zero(const tnode_t *tn) 3054 { 3055 3056 return tn->tn_op == CON && 3057 tn->tn_type->t_tspec == INT && 3058 tn->u.value.u.integer == 0; 3059 } 3060 3061 static void 3062 check_null_effect(const tnode_t *tn) 3063 { 3064 3065 if (hflag && 3066 !has_side_effect(tn) && 3067 !(is_void_cast(tn) && is_local_symbol(tn->u.ops.left)) && 3068 !(is_void_cast(tn) && is_int_constant_zero(tn->u.ops.left))) { 3069 /* expression has null effect */ 3070 warning(129); 3071 } 3072 } 3073 3074 /* 3075 * Check the types for specific operators and type combinations. 3076 * 3077 * At this point, the operands already conform to the type requirements of 3078 * the operator, such as being integer, floating or scalar. 3079 */ 3080 static bool 3081 typeok_op(op_t op, int arg, 3082 const tnode_t *ln, const type_t *ltp, tspec_t lt, 3083 const tnode_t *rn, const type_t *rtp, tspec_t rt) 3084 { 3085 switch (op) { 3086 case ARROW: 3087 return typeok_arrow(lt); 3088 case POINT: 3089 return typeok_point(ln, ltp, lt); 3090 case INCBEF: 3091 case DECBEF: 3092 case INCAFT: 3093 case DECAFT: 3094 return typeok_incdec(op, ln, ltp); 3095 case INDIR: 3096 return typeok_indir(ltp, lt); 3097 case ADDR: 3098 return typeok_address(op, ln, ltp, lt); 3099 case PLUS: 3100 return typeok_plus(op, ltp, lt, rtp, rt); 3101 case MINUS: 3102 return typeok_minus(op, ltp, lt, rtp, rt); 3103 case SHL: 3104 typeok_shl(op, lt, rt); 3105 goto shift; 3106 case SHR: 3107 typeok_shr(op, ln, lt, rn, rt); 3108 shift: 3109 typeok_shift(ltp, lt, rn, rt); 3110 break; 3111 case LT: 3112 case LE: 3113 case GT: 3114 case GE: 3115 compare: 3116 return typeok_compare(op, ln, ltp, lt, rn, rtp, rt); 3117 case EQ: 3118 case NE: 3119 if (is_typeok_eq(ln, lt, rn, rt)) 3120 break; 3121 goto compare; 3122 case QUEST: 3123 return typeok_quest(lt, rn); 3124 case COLON: 3125 return typeok_colon(ln, ltp, lt, rn, rtp, rt); 3126 case ASSIGN: 3127 case INIT: 3128 case FARG: 3129 case RETURN: 3130 if (!check_assign_types_compatible(op, arg, ln, rn)) 3131 return false; 3132 goto assign; 3133 case MULASS: 3134 case DIVASS: 3135 case MODASS: 3136 goto assign; 3137 case ADDASS: 3138 case SUBASS: 3139 if ((lt == PTR && !is_integer(rt)) || rt == PTR) { 3140 warn_incompatible_types(op, ltp, lt, rtp, rt); 3141 return false; 3142 } 3143 goto assign; 3144 case SHLASS: 3145 goto assign; 3146 case SHRASS: 3147 if (pflag && !is_uinteger(lt) && 3148 !(!allow_c90 && is_uinteger(rt))) { 3149 /* bitwise '%s' on signed value possibly nonportable */ 3150 warning(117, op_name(op)); 3151 } 3152 goto assign; 3153 case ANDASS: 3154 case XORASS: 3155 case ORASS: 3156 assign: 3157 return typeok_assign(op, ln, ltp, lt); 3158 case COMMA: 3159 if (!modtab[ln->tn_op].m_has_side_effect) 3160 check_null_effect(ln); 3161 break; 3162 default: 3163 break; 3164 } 3165 return true; 3166 } 3167 3168 static void 3169 check_bad_enum_operation(op_t op, const tnode_t *ln, const tnode_t *rn) 3170 { 3171 3172 if (!eflag) 3173 return; 3174 3175 /* Allow enum in array indices. */ 3176 if (op == PLUS && 3177 ((ln->tn_type->t_is_enum && rn->tn_type->t_tspec == PTR) || 3178 (rn->tn_type->t_is_enum && ln->tn_type->t_tspec == PTR))) { 3179 return; 3180 } 3181 3182 /* dubious operation '%s' on enum */ 3183 warning(241, op_name(op)); 3184 } 3185 3186 static void 3187 check_enum_type_mismatch(op_t op, int arg, const tnode_t *ln, const tnode_t *rn) 3188 { 3189 const mod_t *mp = &modtab[op]; 3190 3191 if (ln->tn_type->u.enumer != rn->tn_type->u.enumer) { 3192 switch (op) { 3193 case INIT: 3194 /* enum type mismatch between '%s' and '%s' in ... */ 3195 warning(210, 3196 type_name(ln->tn_type), type_name(rn->tn_type)); 3197 break; 3198 case FARG: 3199 /* function expects '%s', passing '%s' for arg #%d */ 3200 warning(156, 3201 type_name(ln->tn_type), type_name(rn->tn_type), 3202 arg); 3203 break; 3204 case RETURN: 3205 /* function has return type '%s' but returns '%s' */ 3206 warning(211, 3207 type_name(ln->tn_type), type_name(rn->tn_type)); 3208 break; 3209 default: 3210 /* enum type mismatch: '%s' '%s' '%s' */ 3211 warning(130, type_name(ln->tn_type), op_name(op), 3212 type_name(rn->tn_type)); 3213 break; 3214 } 3215 } else if (Pflag && eflag && mp->m_comparison && op != EQ && op != NE) 3216 /* operator '%s' assumes that '%s' is ordered */ 3217 warning(243, op_name(op), type_name(ln->tn_type)); 3218 } 3219 3220 static void 3221 check_enum_int_mismatch(op_t op, int arg, const tnode_t *ln, const tnode_t *rn) 3222 { 3223 3224 if (!eflag) 3225 return; 3226 3227 switch (op) { 3228 case INIT: 3229 /* 3230 * Initialization with 0 is allowed. Otherwise, all implicit 3231 * initializations would need to be warned upon as well. 3232 */ 3233 if (!rn->tn_type->t_is_enum && rn->tn_op == CON && 3234 is_integer(rn->tn_type->t_tspec) && 3235 rn->u.value.u.integer == 0) { 3236 return; 3237 } 3238 /* initialization of '%s' with '%s' */ 3239 warning(277, type_name(ln->tn_type), type_name(rn->tn_type)); 3240 break; 3241 case FARG: 3242 /* combination of '%s' and '%s', arg #%d */ 3243 warning(278, 3244 type_name(ln->tn_type), type_name(rn->tn_type), arg); 3245 break; 3246 case RETURN: 3247 /* combination of '%s' and '%s' in return */ 3248 warning(279, type_name(ln->tn_type), type_name(rn->tn_type)); 3249 break; 3250 default: 3251 /* combination of '%s' and '%s', op '%s' */ 3252 warning(242, type_name(ln->tn_type), type_name(rn->tn_type), 3253 op_name(op)); 3254 break; 3255 } 3256 } 3257 3258 static void 3259 typeok_enum(op_t op, const mod_t *mp, int arg, 3260 const tnode_t *ln, const type_t *ltp, 3261 const tnode_t *rn, const type_t *rtp) 3262 { 3263 if (mp->m_bad_on_enum && 3264 (ltp->t_is_enum || (mp->m_binary && rtp->t_is_enum))) { 3265 check_bad_enum_operation(op, ln, rn); 3266 } else if (mp->m_valid_on_enum && 3267 (ltp->t_is_enum && rtp != NULL && rtp->t_is_enum)) { 3268 check_enum_type_mismatch(op, arg, ln, rn); 3269 } else if (mp->m_valid_on_enum && 3270 (ltp->t_is_enum || (rtp != NULL && rtp->t_is_enum))) { 3271 check_enum_int_mismatch(op, arg, ln, rn); 3272 } 3273 } 3274 3275 /* Perform most type checks. Return whether the types are ok. */ 3276 bool 3277 typeok(op_t op, int arg, const tnode_t *ln, const tnode_t *rn) 3278 { 3279 3280 const mod_t *mp = &modtab[op]; 3281 3282 type_t *ltp = ln->tn_type; 3283 tspec_t lt = ltp->t_tspec; 3284 3285 type_t *rtp = mp->m_binary ? rn->tn_type : NULL; 3286 tspec_t rt = mp->m_binary ? rtp->t_tspec : NO_TSPEC; 3287 3288 if (Tflag && !typeok_scalar_strict_bool(op, mp, arg, ln, rn)) 3289 return false; 3290 if (!typeok_scalar(op, mp, ltp, lt, rtp, rt)) 3291 return false; 3292 3293 if (!typeok_op(op, arg, ln, ltp, lt, rn, rtp, rt)) 3294 return false; 3295 3296 typeok_enum(op, mp, arg, ln, ltp, rn, rtp); 3297 return true; 3298 } 3299 3300 /* In traditional C, keep unsigned and promote FLOAT to DOUBLE. */ 3301 static tspec_t 3302 promote_trad(tspec_t t) 3303 { 3304 3305 if (t == UCHAR || t == USHORT) 3306 return UINT; 3307 if (t == CHAR || t == SCHAR || t == SHORT) 3308 return INT; 3309 if (t == FLOAT) 3310 return DOUBLE; 3311 if (t == ENUM) 3312 return INT; 3313 return t; 3314 } 3315 3316 /* 3317 * C99 6.3.1.1p2 requires for types with lower rank than int that "If an int 3318 * can represent all the values of the original type, the value is converted 3319 * to an int; otherwise it is converted to an unsigned int", and that "All 3320 * other types are unchanged by the integer promotions". 3321 */ 3322 static tspec_t 3323 promote_c90(const tnode_t *tn, tspec_t t, bool farg) 3324 { 3325 if (tn->tn_type->t_bitfield) { 3326 unsigned int width = tn->tn_type->t_bit_field_width; 3327 unsigned int int_width = size_in_bits(INT); 3328 // XXX: What about _Bool bit-fields, since C99? 3329 if (width < int_width) 3330 return INT; 3331 if (width == int_width) 3332 return is_uinteger(t) ? UINT : INT; 3333 return t; 3334 } 3335 3336 if (t == CHAR || t == SCHAR) 3337 return INT; 3338 if (t == UCHAR) 3339 return size_in_bits(CHAR) < size_in_bits(INT) ? INT : UINT; 3340 if (t == SHORT) 3341 return INT; 3342 if (t == USHORT) 3343 return size_in_bits(SHORT) < size_in_bits(INT) ? INT : UINT; 3344 if (t == ENUM) 3345 return INT; 3346 if (farg && t == FLOAT) 3347 return DOUBLE; 3348 return t; 3349 } 3350 3351 /* 3352 * Performs the "integer promotions" (C99 6.3.1.1p2), which convert small 3353 * integer types to either int or unsigned int. 3354 * 3355 * If allow_c90 is unset or the operand is a function argument with no type 3356 * information (no prototype or variable # of args), converts float to double. 3357 */ 3358 tnode_t * 3359 promote(op_t op, bool farg, tnode_t *tn) 3360 { 3361 3362 const type_t *otp = tn->tn_type; 3363 tspec_t ot = otp->t_tspec; 3364 if (!is_arithmetic(ot)) 3365 return tn; 3366 3367 tspec_t nt = allow_c90 ? promote_c90(tn, ot, farg) : promote_trad(ot); 3368 if (nt == ot) 3369 return tn; 3370 3371 type_t *ntp = expr_dup_type(gettyp(nt)); 3372 ntp->t_tspec = nt; 3373 ntp->t_is_enum = otp->t_is_enum; 3374 if (ntp->t_is_enum) 3375 ntp->u.enumer = otp->u.enumer; 3376 ntp->t_bitfield = otp->t_bitfield; 3377 if (ntp->t_bitfield) { 3378 ntp->t_bit_field_width = otp->t_bit_field_width; 3379 ntp->t_bit_field_offset = otp->t_bit_field_offset; 3380 } 3381 if (ntp->t_bitfield && is_uinteger(ot) && !is_uinteger(nt)) 3382 ntp->t_bit_field_width++; 3383 return convert(op, 0, ntp, tn); 3384 } 3385 3386 static void 3387 check_lossy_floating_to_integer_conversion( 3388 op_t op, int arg, const type_t *tp, const tnode_t *tn) 3389 { 3390 long double x = tn->u.value.u.floating; 3391 integer_constraints ic = ic_any(tp); 3392 if (is_uinteger(tp->t_tspec) 3393 ? x >= ic.umin && x <= ic.umax && x == (uint64_t)x 3394 : x >= ic.smin && x <= ic.smax && x == (int64_t)x) 3395 return; 3396 if (op == FARG) 3397 /* lossy conversion of %Lg to '%s', arg #%d */ 3398 warning(380, x, type_name(tp), arg); 3399 else 3400 /* lossy conversion of %Lg to '%s' */ 3401 warning(381, x, type_name(tp)); 3402 } 3403 3404 static void 3405 convert_integer_from_floating( 3406 op_t op, int arg, const type_t *tp, const tnode_t *tn) 3407 { 3408 3409 if (op == CVT) 3410 /* cast from floating point '%s' to integer '%s' */ 3411 query_message(2, type_name(tn->tn_type), type_name(tp)); 3412 else 3413 /* implicit conversion from floating point '%s' to ... */ 3414 query_message(1, type_name(tn->tn_type), type_name(tp)); 3415 if (tn->tn_op == CON) 3416 check_lossy_floating_to_integer_conversion(op, arg, tp, tn); 3417 } 3418 3419 static bool 3420 should_warn_about_prototype_conversion(tspec_t nt, 3421 tspec_t ot, const tnode_t *ptn) 3422 { 3423 3424 if (nt == ot) 3425 return false; 3426 3427 if (nt == ENUM && ot == INT) 3428 return false; 3429 3430 if (is_floating(nt) != is_floating(ot) || 3431 portable_rank_cmp(nt, ot) != 0) { 3432 /* representation and/or width change */ 3433 if (!is_integer(ot)) 3434 return true; 3435 /* 3436 * XXX: Investigate whether this rule makes sense; see 3437 * tests/usr.bin/xlint/lint1/platform_long.c. 3438 */ 3439 return portable_rank_cmp(ot, INT) > 0; 3440 } 3441 3442 if (!hflag) 3443 return false; 3444 3445 /* 3446 * If the types differ only in sign and the argument has the same 3447 * representation in both types, print no warning. 3448 */ 3449 if (ptn->tn_op == CON && is_integer(nt) && 3450 signed_type(nt) == signed_type(ot) && 3451 !msb(ptn->u.value.u.integer, ot)) 3452 return false; 3453 3454 return true; 3455 } 3456 3457 /* 3458 * Warn if a prototype causes a type conversion that is different from what 3459 * would happen to the same argument in the absence of a prototype. This 3460 * check is intended for code that needs to stay compatible with pre-C90 C. 3461 * 3462 * Errors/warnings about illegal type combinations are already printed 3463 * in check_assign_types_compatible(). 3464 */ 3465 static void 3466 check_prototype_conversion(int arg, tspec_t nt, tspec_t ot, type_t *tp, 3467 tnode_t *tn) 3468 { 3469 3470 if (!is_arithmetic(nt) || !is_arithmetic(ot)) 3471 return; 3472 3473 /* 3474 * If the type of the formal parameter is char/short, a warning would 3475 * be useless, because functions declared the old style can't expect 3476 * char/short arguments. 3477 */ 3478 if (nt == CHAR || nt == SCHAR || nt == UCHAR || 3479 nt == SHORT || nt == USHORT) 3480 return; 3481 3482 tnode_t *ptn = promote(NOOP, true, tn); 3483 ot = ptn->tn_type->t_tspec; 3484 3485 if (should_warn_about_prototype_conversion(nt, ot, ptn)) { 3486 /* argument %d is converted from '%s' to '%s' ... */ 3487 warning(259, arg, type_name(tn->tn_type), type_name(tp)); 3488 } 3489 } 3490 3491 /* 3492 * When converting a large integer type to a small integer type, in some 3493 * cases the value of the actual expression is further restricted than the 3494 * type bounds, such as in (expr & 0xFF) or (expr % 100) or (expr >> 24). 3495 */ 3496 static bool 3497 can_represent(const type_t *tp, const tnode_t *tn) 3498 { 3499 uint64_t nmask = value_bits(width_in_bits(tp)); 3500 if (!is_uinteger(tp->t_tspec)) 3501 nmask >>= 1; 3502 3503 integer_constraints c = ic_expr(tn); 3504 if ((~c.bclr & ~nmask) == 0) 3505 return true; 3506 3507 integer_constraints tpc = ic_any(tp); 3508 if (is_uinteger(tp->t_tspec) 3509 ? tpc.umin <= c.umin && tpc.umax >= c.umax 3510 : tpc.smin <= c.smin && tpc.smax >= c.smax) 3511 return true; 3512 3513 debug_enter(); 3514 debug_step("type '%s' cannot represent:", type_name(tp)); 3515 debug_node(tn); 3516 debug_leave(); 3517 return false; 3518 } 3519 3520 static bool 3521 should_warn_about_integer_conversion(const type_t *ntp, tspec_t nt, 3522 const tnode_t *otn, tspec_t ot) 3523 { 3524 3525 // XXX: The portable_rank_cmp aims at portable mode, independent of the 3526 // current platform, while can_represent acts on the actual type sizes 3527 // from the current platform. This mix is inconsistent, but anything 3528 // else would make the exact conditions too complicated to grasp. 3529 if (aflag > 0 && portable_rank_cmp(nt, ot) < 0) { 3530 if (ot == LONG || ot == ULONG 3531 || ot == LLONG || ot == ULLONG 3532 #ifdef INT128_SIZE 3533 || ot == INT128 || ot == UINT128 3534 #endif 3535 || aflag > 1) 3536 return !can_represent(ntp, otn); 3537 } 3538 return false; 3539 } 3540 3541 static void 3542 convert_integer_from_integer(op_t op, int arg, tspec_t nt, tspec_t ot, 3543 type_t *tp, tnode_t *tn) 3544 { 3545 3546 if (tn->tn_op == CON) 3547 return; 3548 3549 if (op == CVT) 3550 return; 3551 3552 if (Pflag && pflag && aflag > 0 && 3553 portable_rank_cmp(nt, ot) > 0 && 3554 is_uinteger(nt) != is_uinteger(ot)) { 3555 if (op == FARG) 3556 /* conversion to '%s' may sign-extend ... */ 3557 warning(297, type_name(tp), arg); 3558 else 3559 /* conversion to '%s' may sign-extend ... */ 3560 warning(131, type_name(tp)); 3561 } 3562 3563 if (Pflag && portable_rank_cmp(nt, ot) > 0 && 3564 (tn->tn_op == PLUS || tn->tn_op == MINUS || tn->tn_op == MULT || 3565 tn->tn_op == SHL)) { 3566 /* suggest cast from '%s' to '%s' on op '%s' to ... */ 3567 warning(324, type_name(gettyp(ot)), type_name(tp), 3568 op_name(tn->tn_op)); 3569 } 3570 3571 if (should_warn_about_integer_conversion(tp, nt, tn, ot)) { 3572 if (op == FARG) { 3573 /* conversion from '%s' to '%s' may lose ... */ 3574 warning(298, 3575 type_name(tn->tn_type), type_name(tp), arg); 3576 } else { 3577 /* conversion from '%s' to '%s' may lose accuracy */ 3578 warning(132, 3579 type_name(tn->tn_type), type_name(tp)); 3580 } 3581 } 3582 3583 if (any_query_enabled && is_uinteger(nt) != is_uinteger(ot)) 3584 /* implicit conversion changes sign from '%s' to '%s' */ 3585 query_message(3, type_name(tn->tn_type), type_name(tp)); 3586 } 3587 3588 static void 3589 convert_integer_from_pointer(op_t op, tspec_t nt, type_t *tp, tnode_t *tn) 3590 { 3591 3592 if (tn->tn_op == CON) 3593 return; 3594 if (op != CVT) 3595 return; /* We already got an error. */ 3596 if (portable_rank_cmp(nt, PTR) >= 0) 3597 return; 3598 3599 if (pflag && size_in_bits(nt) >= size_in_bits(PTR)) { 3600 /* conversion of pointer to '%s' may lose bits */ 3601 warning(134, type_name(tp)); 3602 } else { 3603 /* conversion of pointer to '%s' loses bits */ 3604 warning(133, type_name(tp)); 3605 } 3606 } 3607 3608 static bool 3609 struct_starts_with(const type_t *struct_tp, const type_t *member_tp) 3610 { 3611 3612 return struct_tp->u.sou->sou_first_member != NULL && 3613 types_compatible(struct_tp->u.sou->sou_first_member->s_type, 3614 member_tp, true, false, NULL); 3615 } 3616 3617 static bool 3618 is_byte_array(const type_t *tp) 3619 { 3620 3621 return tp->t_tspec == ARRAY && 3622 (tp->t_subt->t_tspec == CHAR || tp->t_subt->t_tspec == UCHAR); 3623 } 3624 3625 static bool 3626 union_contains(const type_t *utp, const type_t *mtp) 3627 { 3628 for (const sym_t *mem = utp->u.sou->sou_first_member; 3629 mem != NULL; mem = mem->s_next) { 3630 if (types_compatible(mem->s_type, mtp, true, false, NULL)) 3631 return true; 3632 } 3633 return false; 3634 } 3635 3636 static bool 3637 should_warn_about_pointer_cast(const type_t *nstp, tspec_t nst, 3638 const type_t *ostp, tspec_t ost) 3639 { 3640 3641 while (nst == ARRAY) 3642 nstp = nstp->t_subt, nst = nstp->t_tspec; 3643 while (ost == ARRAY) 3644 ostp = ostp->t_subt, ost = ostp->t_tspec; 3645 3646 if (nst == STRUCT && ost == STRUCT && 3647 (struct_starts_with(nstp, ostp) || 3648 struct_starts_with(ostp, nstp))) 3649 return false; 3650 3651 if (is_incomplete(nstp) || is_incomplete(ostp)) 3652 return false; 3653 3654 if (nst == CHAR || nst == UCHAR) 3655 return false; /* for the sake of traditional C code */ 3656 if (ost == CHAR || ost == UCHAR) 3657 return false; /* for the sake of traditional C code */ 3658 3659 /* Allow cast between pointers to sockaddr variants. */ 3660 if (nst == STRUCT && ost == STRUCT) { 3661 const sym_t *nmem = nstp->u.sou->sou_first_member; 3662 const sym_t *omem = ostp->u.sou->sou_first_member; 3663 while (nmem != NULL && omem != NULL && 3664 types_compatible(nmem->s_type, omem->s_type, 3665 true, false, NULL)) 3666 nmem = nmem->s_next, omem = omem->s_next; 3667 if (nmem != NULL && is_byte_array(nmem->s_type)) 3668 return false; 3669 if (omem != NULL && is_byte_array(omem->s_type)) 3670 return false; 3671 if (nmem == NULL && omem == NULL) 3672 return false; 3673 } 3674 3675 if (nst == UNION || ost == UNION) { 3676 const type_t *union_tp = nst == UNION ? nstp : ostp; 3677 const type_t *other_tp = nst == UNION ? ostp : nstp; 3678 if (union_contains(union_tp, other_tp)) 3679 return false; 3680 } 3681 3682 if (is_struct_or_union(nst) && is_struct_or_union(ost)) 3683 return nstp->u.sou != ostp->u.sou; 3684 3685 enum rank_kind rk1 = type_properties(nst)->tt_rank_kind; 3686 enum rank_kind rk2 = type_properties(ost)->tt_rank_kind; 3687 if (rk1 != rk2 || rk1 == RK_NONE) 3688 return true; 3689 3690 return portable_rank_cmp(nst, ost) != 0; 3691 } 3692 3693 static void 3694 convert_pointer_from_pointer(type_t *ntp, tnode_t *tn) 3695 { 3696 const type_t *nstp = ntp->t_subt; 3697 const type_t *otp = tn->tn_type; 3698 const type_t *ostp = otp->t_subt; 3699 tspec_t nst = nstp->t_tspec; 3700 tspec_t ost = ostp->t_tspec; 3701 3702 if (nst == VOID || ost == VOID) { 3703 /* TODO: C99 behaves like C90 here. */ 3704 if (!allow_trad && !allow_c99 && (nst == FUNC || ost == FUNC)) { 3705 const char *nts, *ots; 3706 /* null pointers are already handled in convert() */ 3707 *(nst == FUNC ? &nts : &ots) = "function pointer"; 3708 *(nst == VOID ? &nts : &ots) = "'void *'"; 3709 /* conversion of %s to %s requires a cast */ 3710 warning(303, ots, nts); 3711 } 3712 return; 3713 } 3714 if (nst == FUNC && ost == FUNC) 3715 return; 3716 if (nst == FUNC || ost == FUNC) { 3717 /* converting '%s' to '%s' is questionable */ 3718 warning(229, type_name(otp), type_name(ntp)); 3719 return; 3720 } 3721 3722 if (hflag && alignment(nstp) > alignment(ostp) && 3723 ost != CHAR && ost != UCHAR && 3724 !is_incomplete(ostp) && 3725 !(nst == UNION && union_contains(nstp, ostp))) { 3726 /* converting '%s' to '%s' increases alignment ... */ 3727 warning(135, type_name(otp), type_name(ntp), 3728 alignment(ostp), alignment(nstp)); 3729 } 3730 3731 if (cflag && should_warn_about_pointer_cast(nstp, nst, ostp, ost)) { 3732 /* pointer cast from '%s' to unrelated '%s' */ 3733 warning(247, type_name(ostp), type_name(nstp)); 3734 } 3735 } 3736 3737 /* 3738 * Insert a conversion operator, which converts the type of the node 3739 * to another given type. 3740 * 3741 * Possible values for 'op': 3742 * CVT a cast-expression 3743 * binary integer promotion for one of the operands, or a usual 3744 * arithmetic conversion 3745 * binary plain or compound assignments to bit-fields 3746 * FARG 'arg' is the number of the parameter (used for warnings) 3747 * NOOP several other implicit conversions 3748 * ... 3749 */ 3750 tnode_t * 3751 convert(op_t op, int arg, type_t *tp, tnode_t *tn) 3752 { 3753 tspec_t nt = tp->t_tspec; 3754 tspec_t ot = tn->tn_type->t_tspec; 3755 3756 if (allow_trad && allow_c90 && op == FARG) 3757 check_prototype_conversion(arg, nt, ot, tp, tn); 3758 3759 if (nt == BOOL) { 3760 /* No further checks. */ 3761 3762 } else if (is_integer(nt)) { 3763 if (ot == BOOL) { 3764 /* No further checks. */ 3765 } else if (is_integer(ot)) 3766 convert_integer_from_integer(op, arg, nt, ot, tp, tn); 3767 else if (is_floating(ot)) 3768 convert_integer_from_floating(op, arg, tp, tn); 3769 else if (ot == PTR) 3770 convert_integer_from_pointer(op, nt, tp, tn); 3771 3772 } else if (is_floating(nt)) { 3773 if (is_integer(ot) && op != CVT) { 3774 /* implicit conversion from integer '%s' to ... */ 3775 query_message(19, 3776 type_name(tn->tn_type), type_name(tp)); 3777 } 3778 3779 } else if (nt == PTR) { 3780 if (is_null_pointer(tn)) { 3781 /* a null pointer may be assigned to any pointer. */ 3782 } else if (ot == PTR && op == CVT) 3783 convert_pointer_from_pointer(tp, tn); 3784 } 3785 3786 tnode_t *ntn = expr_alloc_tnode(); 3787 ntn->tn_op = CVT; 3788 ntn->tn_type = tp; 3789 ntn->tn_cast = op == CVT; 3790 ntn->tn_sys |= tn->tn_sys; 3791 ntn->u.ops.right = NULL; 3792 if (tn->tn_op != CON || nt == VOID) { 3793 ntn->u.ops.left = tn; 3794 } else { 3795 ntn->tn_op = CON; 3796 convert_constant(op, arg, ntn->tn_type, &ntn->u.value, 3797 &tn->u.value); 3798 } 3799 3800 return ntn; 3801 } 3802 3803 static void 3804 convert_constant_from_floating(op_t op, int arg, const type_t *ntp, 3805 tspec_t nt, val_t *nv, val_t *ov) 3806 { 3807 long double max = 0.0, min = 0.0; 3808 3809 switch (nt) { 3810 case CHAR: 3811 max = TARG_CHAR_MAX; min = TARG_CHAR_MIN; break; 3812 case UCHAR: 3813 max = TARG_UCHAR_MAX; min = 0; break; 3814 case SCHAR: 3815 max = TARG_SCHAR_MAX; min = TARG_SCHAR_MIN; break; 3816 case SHORT: 3817 max = TARG_SHRT_MAX; min = TARG_SHRT_MIN; break; 3818 case USHORT: 3819 max = TARG_USHRT_MAX; min = 0; break; 3820 case ENUM: 3821 case INT: 3822 max = TARG_INT_MAX; min = TARG_INT_MIN; break; 3823 case UINT: 3824 max = TARG_UINT_MAX; min = 0; break; 3825 case LONG: 3826 max = TARG_LONG_MAX; min = TARG_LONG_MIN; break; 3827 case ULONG: 3828 max = TARG_ULONG_MAX; min = 0; break; 3829 case LLONG: 3830 max = LLONG_MAX; min = LLONG_MIN; break; 3831 case ULLONG: 3832 max = ULLONG_MAX; min = 0; break; 3833 case FLOAT: 3834 case FCOMPLEX: 3835 max = FLT_MAX; min = -FLT_MAX; break; 3836 case DOUBLE: 3837 case DCOMPLEX: 3838 max = DBL_MAX; min = -DBL_MAX; break; 3839 case LDOUBLE: 3840 case LCOMPLEX: 3841 /* LINTED 248; see floating_error_value. */ 3842 max = LDBL_MAX; min = -max; break; 3843 default: 3844 lint_assert(/*CONSTCOND*/false); 3845 } 3846 if (ov->u.floating > max || ov->u.floating < min) { 3847 lint_assert(nt != LDOUBLE); 3848 const char *ot_name = type_name(gettyp(ov->v_tspec)); 3849 const char *nt_name = type_name(ntp); 3850 if (is_integer(nt)) 3851 goto after_warning; 3852 if (op == FARG) 3853 /* conversion of '%s' to '%s' is out of range, ... */ 3854 warning(295, ot_name, nt_name, arg); 3855 else 3856 /* conversion of '%s' to '%s' is out of range */ 3857 warning(119, ot_name, nt_name); 3858 after_warning: 3859 ov->u.floating = ov->u.floating > 0 ? max : min; 3860 } 3861 3862 if (nt == FLOAT || nt == FCOMPLEX) 3863 nv->u.floating = (float)ov->u.floating; 3864 else if (nt == DOUBLE || nt == DCOMPLEX) 3865 nv->u.floating = (double)ov->u.floating; 3866 else if (nt == LDOUBLE || nt == LCOMPLEX) 3867 nv->u.floating = ov->u.floating; 3868 else 3869 nv->u.integer = (int64_t)ov->u.floating; 3870 } 3871 3872 static bool 3873 convert_constant_to_floating(tspec_t nt, val_t *nv, 3874 tspec_t ot, const val_t *v) 3875 { 3876 if (nt == FLOAT) { 3877 nv->u.floating = (ot == PTR || is_uinteger(ot)) ? 3878 (float)(uint64_t)v->u.integer : (float)v->u.integer; 3879 } else if (nt == DOUBLE) { 3880 nv->u.floating = (ot == PTR || is_uinteger(ot)) ? 3881 (double)(uint64_t)v->u.integer : (double)v->u.integer; 3882 } else if (nt == LDOUBLE) { 3883 nv->u.floating = (ot == PTR || is_uinteger(ot)) 3884 ? (long double)(uint64_t)v->u.integer 3885 : (long double)v->u.integer; 3886 } else 3887 return false; 3888 return true; 3889 } 3890 3891 /* 3892 * Print a warning if bits which were set are lost due to the conversion. 3893 * This can happen with operator ORASS only. 3894 */ 3895 static void 3896 convert_constant_check_range_bitor(size_t nsz, size_t osz, const val_t *v, 3897 uint64_t xmask, op_t op) 3898 { 3899 if (nsz < osz && (v->u.integer & xmask) != 0) 3900 /* constant truncated by conversion, op '%s' */ 3901 warning(306, op_name(op)); 3902 } 3903 3904 static void 3905 convert_constant_check_range_bitand(size_t nsz, size_t osz, 3906 uint64_t xmask, const val_t *nv, 3907 tspec_t ot, const val_t *v, 3908 const type_t *tp, op_t op) 3909 { 3910 if (nsz > osz && 3911 (nv->u.integer & bit((unsigned int)(osz - 1))) != 0 && 3912 (nv->u.integer & xmask) != xmask) { 3913 /* extra bits set to 0 in conversion of '%s' to '%s', ... */ 3914 warning(309, type_name(gettyp(ot)), 3915 type_name(tp), op_name(op)); 3916 } else if (nsz < osz && 3917 (v->u.integer & xmask) != xmask && 3918 (v->u.integer & xmask) != 0) 3919 /* constant truncated by conversion, op '%s' */ 3920 warning(306, op_name(op)); 3921 } 3922 3923 static void 3924 convert_constant_check_range_signed(op_t op, int arg, 3925 const type_t *ntp, int64_t ov) 3926 { 3927 if (op == ASSIGN) 3928 /* assignment of negative constant %lld to unsigned ... */ 3929 warning(164, (long long)ov, type_name(ntp)); 3930 else if (op == INIT) 3931 /* initialization of unsigned type '%s' with negative ... */ 3932 warning(221, type_name(ntp), (long long)ov); 3933 else if (op == FARG) 3934 /* conversion of negative constant %lld to unsigned ... */ 3935 warning(296, (long long)ov, type_name(ntp), arg); 3936 else if (modtab[op].m_comparison) { 3937 /* handled by check_integer_comparison() */ 3938 } else 3939 /* conversion of negative constant %lld to unsigned ... */ 3940 warning(222, (long long)ov, type_name(ntp)); 3941 } 3942 3943 /* 3944 * Loss of significant bit(s). All truncated bits of unsigned types or all 3945 * truncated bits plus the msb of the target for signed types are considered 3946 * to be significant bits. Loss of significant bits means that at least one 3947 * of the bits was set in an unsigned type or that at least one but not all 3948 * of the bits was set in a signed type. Loss of significant bits means that 3949 * it is not possible, also not with necessary casts, to convert back to the 3950 * original type. An example for a necessary cast is: 3951 * char c; int i; c = 128; 3952 * i = c; ** yields -128 ** 3953 * i = (unsigned char)c; ** yields 128 ** 3954 */ 3955 static void 3956 warn_constant_check_range_truncated(op_t op, int arg, const type_t *tp, 3957 tspec_t ot) 3958 { 3959 if (op == ASSIGN && tp->t_bitfield) 3960 /* precision lost in bit-field assignment */ 3961 warning(166); 3962 else if (op == ASSIGN) 3963 /* constant truncated by assignment */ 3964 warning(165); 3965 else if (op == INIT && tp->t_bitfield) 3966 /* bit-field initializer does not fit */ 3967 warning(180); 3968 else if (op == INIT) 3969 /* initializer does not fit */ 3970 warning(178); 3971 else if (op == CASE) 3972 /* case label affected by conversion */ 3973 warning(196); 3974 else if (op == FARG) 3975 /* conversion of '%s' to '%s' is out of range, arg #%d */ 3976 warning(295, type_name(gettyp(ot)), type_name(tp), arg); 3977 else 3978 /* conversion of '%s' to '%s' is out of range */ 3979 warning(119, type_name(gettyp(ot)), type_name(tp)); 3980 } 3981 3982 static void 3983 warn_constant_check_range_loss(op_t op, int arg, const type_t *tp, 3984 tspec_t ot) 3985 { 3986 if (op == ASSIGN && tp->t_bitfield) 3987 /* precision lost in bit-field assignment */ 3988 warning(166); 3989 else if (op == INIT && tp->t_bitfield) 3990 /* bit-field initializer out of range */ 3991 warning(11); 3992 else if (op == CASE) 3993 /* case label affected by conversion */ 3994 warning(196); 3995 else if (op == FARG) 3996 /* conversion of '%s' to '%s' is out of range, arg #%d */ 3997 warning(295, type_name(gettyp(ot)), type_name(tp), arg); 3998 else 3999 /* conversion of '%s' to '%s' is out of range */ 4000 warning(119, type_name(gettyp(ot)), type_name(tp)); 4001 } 4002 4003 static void 4004 convert_constant_check_range(tspec_t ot, const type_t *tp, tspec_t nt, 4005 op_t op, int arg, const val_t *v, val_t *nv) 4006 { 4007 unsigned int obitsz, nbitsz; 4008 uint64_t xmask, xmsk1; 4009 4010 obitsz = size_in_bits(ot); 4011 nbitsz = tp->t_bitfield ? tp->t_bit_field_width : size_in_bits(nt); 4012 xmask = value_bits(nbitsz) ^ value_bits(obitsz); 4013 xmsk1 = value_bits(nbitsz) ^ value_bits(obitsz - 1); 4014 if (op == ORASS || op == BITOR || op == BITXOR) { 4015 convert_constant_check_range_bitor( 4016 nbitsz, obitsz, v, xmask, op); 4017 } else if (op == ANDASS || op == BITAND) { 4018 convert_constant_check_range_bitand( 4019 nbitsz, obitsz, xmask, nv, ot, v, tp, op); 4020 } else if (nt != PTR && is_uinteger(nt) && 4021 ot != PTR && !is_uinteger(ot) && 4022 v->u.integer < 0) 4023 convert_constant_check_range_signed(op, arg, 4024 tp, v->u.integer); 4025 else if (nv->u.integer != v->u.integer && nbitsz <= obitsz && 4026 (v->u.integer & xmask) != 0 && 4027 (is_uinteger(ot) || (v->u.integer & xmsk1) != xmsk1)) 4028 warn_constant_check_range_truncated(op, arg, tp, ot); 4029 else if (nv->u.integer != v->u.integer) 4030 warn_constant_check_range_loss(op, arg, tp, ot); 4031 } 4032 4033 /* Converts a typed constant to a constant of another type. */ 4034 void 4035 convert_constant(op_t op, int arg, const type_t *ntp, val_t *nv, val_t *ov) 4036 { 4037 /* 4038 * TODO: make 'ov' const; the name of this function does not suggest 4039 * that it modifies 'ov'. 4040 */ 4041 tspec_t ot = ov->v_tspec; 4042 tspec_t nt = nv->v_tspec = ntp->t_tspec; 4043 bool range_check = false; 4044 4045 if (nt == BOOL) { /* C99 6.3.1.2 */ 4046 nv->v_unsigned_since_c90 = false; 4047 nv->u.integer = is_nonzero_val(ov) ? 1 : 0; 4048 return; 4049 } 4050 4051 if (ot == FLOAT || ot == DOUBLE || ot == LDOUBLE) 4052 convert_constant_from_floating(op, arg, ntp, nt, nv, ov); 4053 else if (!convert_constant_to_floating(nt, nv, ot, ov)) { 4054 range_check = true; /* Check for lost precision. */ 4055 nv->u.integer = ov->u.integer; 4056 } 4057 4058 if (allow_trad && allow_c90 && ov->v_unsigned_since_c90 && 4059 (is_floating(nt) || ( 4060 (is_integer(nt) && !is_uinteger(nt) && 4061 portable_rank_cmp(nt, ot) > 0)))) { 4062 /* C90 treats constant as unsigned */ 4063 warning(157); 4064 ov->v_unsigned_since_c90 = false; 4065 } 4066 4067 if (is_integer(nt)) { 4068 unsigned int size = ntp->t_bitfield 4069 ? ntp->t_bit_field_width : size_in_bits(nt); 4070 nv->u.integer = convert_integer(nv->u.integer, nt, size); 4071 } 4072 4073 if (range_check && op != CVT) 4074 convert_constant_check_range(ot, ntp, nt, op, arg, ov, nv); 4075 } 4076 4077 tnode_t * 4078 build_sizeof(const type_t *tp) 4079 { 4080 unsigned int size_in_bytes = type_size_in_bits(tp) / CHAR_SIZE; 4081 tnode_t *tn = build_integer_constant(SIZEOF_TSPEC, size_in_bytes); 4082 tn->tn_system_dependent = true; 4083 debug_step("build_sizeof '%s' = %u", type_name(tp), size_in_bytes); 4084 return tn; 4085 } 4086 4087 tnode_t * 4088 build_offsetof(const type_t *tp, designation dn) 4089 { 4090 unsigned int offset_in_bits = 0; 4091 4092 if (!is_struct_or_union(tp->t_tspec)) { 4093 /* unacceptable operand of '%s' */ 4094 error(111, "offsetof"); 4095 goto proceed; 4096 } 4097 for (size_t i = 0; i < dn.dn_len; i++) { 4098 const designator *dr = dn.dn_items + i; 4099 if (dr->dr_kind == DK_SUBSCRIPT) { 4100 if (tp->t_tspec != ARRAY) 4101 goto proceed; /* silent error */ 4102 tp = tp->t_subt; 4103 offset_in_bits += (unsigned) dr->dr_subscript 4104 * type_size_in_bits(tp); 4105 } else { 4106 if (!is_struct_or_union(tp->t_tspec)) 4107 goto proceed; /* silent error */ 4108 const char *name = dr->dr_member->s_name; 4109 sym_t *mem = find_member(tp->u.sou, name); 4110 if (mem == NULL) { 4111 /* type '%s' does not have member '%s' */ 4112 error(101, name, type_name(tp)); 4113 goto proceed; 4114 } 4115 tp = mem->s_type; 4116 offset_in_bits += mem->u.s_member.sm_offset_in_bits; 4117 } 4118 } 4119 free(dn.dn_items); 4120 4121 proceed:; 4122 unsigned int offset_in_bytes = offset_in_bits / CHAR_SIZE; 4123 tnode_t *tn = build_integer_constant(SIZEOF_TSPEC, offset_in_bytes); 4124 tn->tn_system_dependent = true; 4125 return tn; 4126 } 4127 4128 unsigned int 4129 type_size_in_bits(const type_t *tp) 4130 { 4131 4132 unsigned int elem = 1; 4133 bool flex = false; 4134 lint_assert(tp != NULL); 4135 while (tp->t_tspec == ARRAY) { 4136 flex = true; /* allow c99 flex arrays [] [0] */ 4137 elem *= tp->u.dimension; 4138 tp = tp->t_subt; 4139 } 4140 if (elem == 0 && !flex) { 4141 /* cannot take size/alignment of incomplete type */ 4142 error(143); 4143 elem = 1; 4144 } 4145 4146 unsigned int elsz; 4147 switch (tp->t_tspec) { 4148 case VOID: 4149 /* cannot take size/alignment of void */ 4150 error(146); 4151 elsz = 1; 4152 break; 4153 case FUNC: 4154 /* cannot take size/alignment of function type '%s' */ 4155 error(144, type_name(tp)); 4156 elsz = 1; 4157 break; 4158 case STRUCT: 4159 case UNION: 4160 if (is_incomplete(tp)) { 4161 /* cannot take size/alignment of incomplete type */ 4162 error(143); 4163 elsz = 1; 4164 } else 4165 elsz = tp->u.sou->sou_size_in_bits; 4166 break; 4167 case ENUM: 4168 if (is_incomplete(tp)) { 4169 /* cannot take size/alignment of incomplete type */ 4170 warning(143); 4171 } 4172 /* FALLTHROUGH */ 4173 default: 4174 if (tp->t_bitfield) 4175 /* cannot take size/alignment of bit-field */ 4176 error(145); 4177 elsz = size_in_bits(tp->t_tspec); 4178 lint_assert(elsz > 0); 4179 break; 4180 } 4181 4182 return elem * elsz; 4183 } 4184 4185 /* C11 6.5.3.4, GCC */ 4186 tnode_t * 4187 build_alignof(const type_t *tp) 4188 { 4189 if (tp->t_tspec == FUNC) { 4190 /* cannot take size/alignment of function type '%s' */ 4191 error(144, type_name(tp)); 4192 return NULL; 4193 } 4194 if (tp->t_tspec == VOID) { 4195 /* cannot take size/alignment of void */ 4196 error(146); 4197 return NULL; 4198 } 4199 if (is_incomplete(tp)) { 4200 /* cannot take size/alignment of incomplete type */ 4201 error(143); 4202 return NULL; 4203 } 4204 if (tp->t_bitfield) { 4205 /* cannot take size/alignment of bit-field */ 4206 error(145); 4207 return NULL; 4208 } 4209 return build_integer_constant(SIZEOF_TSPEC, (int64_t)alignment(tp)); 4210 } 4211 4212 static tnode_t * 4213 cast_to_union(tnode_t *otn, bool sys, type_t *ntp) 4214 { 4215 4216 if (!allow_gcc) { 4217 /* union cast is a GCC extension */ 4218 error(328); 4219 return NULL; 4220 } 4221 4222 for (const sym_t *m = ntp->u.sou->sou_first_member; 4223 m != NULL; m = m->s_next) { 4224 if (types_compatible(m->s_type, otn->tn_type, 4225 false, false, NULL)) { 4226 tnode_t *ntn = build_op(CVT, sys, ntp, otn, NULL); 4227 ntn->tn_cast = true; 4228 return ntn; 4229 } 4230 } 4231 4232 /* type '%s' is not a member of '%s' */ 4233 error(329, type_name(otn->tn_type), type_name(ntp)); 4234 return NULL; 4235 } 4236 4237 // In GCC mode, allow 'nullptr + offset' as a constant expression. 4238 static tnode_t * 4239 null_pointer_offset(tnode_t *tn) 4240 { 4241 uint64_t off = 0; 4242 const tnode_t *n = tn; 4243 while ((n->tn_op == PLUS || n->tn_op == MINUS) 4244 && is_integer(n->u.ops.right->tn_type->t_tspec)) { 4245 off += (uint64_t)n->u.ops.right->u.value.u.integer; 4246 n = n->u.ops.left; 4247 } 4248 if (n->tn_type->t_tspec == PTR 4249 && n->tn_op == ADDR 4250 && n->u.ops.left->tn_op == INDIR 4251 && n->u.ops.left->u.ops.left->tn_op == CON 4252 && n->u.ops.left->u.ops.left->tn_type->t_tspec == PTR) { 4253 off += (uint64_t)n->u.ops.left->u.ops.left->u.value.u.integer; 4254 return build_integer_constant(SIZEOF_TSPEC, (int64_t)off); 4255 } 4256 return tn; 4257 } 4258 4259 tnode_t * 4260 cast(tnode_t *tn, bool sys, type_t *tp) 4261 { 4262 4263 if (tn == NULL) 4264 return NULL; 4265 4266 tn = cconv(tn); 4267 4268 lint_assert(tp != NULL); 4269 tspec_t nt = tp->t_tspec; 4270 tspec_t ot = tn->tn_type->t_tspec; 4271 4272 if (nt == VOID) { 4273 /* 4274 * C90 6.3.4, C99 6.5.4p2 and C11 6.5.4p2 allow any type to be 4275 * cast to void. The only other allowed casts are from a 4276 * scalar type to a scalar type. 4277 */ 4278 } else if (nt == UNION) 4279 return cast_to_union(tn, sys, tp); 4280 else if (nt == STRUCT || nt == ARRAY || nt == FUNC) { 4281 /* Casting to a struct is an undocumented GCC extension. */ 4282 if (!(allow_gcc && nt == STRUCT)) 4283 goto invalid_cast; 4284 } else if (is_struct_or_union(ot)) 4285 goto invalid_cast; 4286 else if (ot == VOID) { 4287 /* improper cast of void expression */ 4288 error(148); 4289 return NULL; 4290 } else if (is_integer(nt) && is_scalar(ot)) { 4291 tn = null_pointer_offset(tn); 4292 } else if (is_floating(nt) && is_arithmetic(ot)) { 4293 /* ok */ 4294 } else if (nt == PTR && is_integer(ot)) { 4295 /* ok */ 4296 } else if (nt == PTR && ot == PTR) { 4297 if (!tp->t_subt->t_const && tn->tn_type->t_subt->t_const) { 4298 if (hflag) 4299 /* cast discards 'const' from type '%s' */ 4300 warning(275, type_name(tn->tn_type)); 4301 } 4302 } else 4303 goto invalid_cast; 4304 4305 if (any_query_enabled 4306 && types_compatible(tp, tn->tn_type, false, false, NULL)) 4307 /* no-op cast from '%s' to '%s' */ 4308 query_message(6, type_name(tn->tn_type), type_name(tp)); 4309 4310 tn = convert(CVT, 0, tp, tn); 4311 tn->tn_cast = true; 4312 tn->tn_sys = sys; 4313 4314 return tn; 4315 4316 invalid_cast: 4317 /* invalid cast from '%s' to '%s' */ 4318 error(147, type_name(tn->tn_type), type_name(tp)); 4319 return NULL; 4320 } 4321 4322 void 4323 add_function_argument(function_call *call, tnode_t *arg) 4324 { 4325 /* 4326 * If there was a serious error in the expression for the argument, 4327 * create a dummy argument so the positions of the remaining arguments 4328 * will not change. 4329 */ 4330 if (arg == NULL) 4331 arg = build_integer_constant(INT, 0); 4332 4333 if (call->args_len >= call->args_cap) { 4334 call->args_cap += 8; 4335 tnode_t **new_args = expr_zero_alloc( 4336 call->args_cap * sizeof(*call->args), "tnode*[]"); 4337 if (call->args_len > 0) 4338 memcpy(new_args, call->args, 4339 call->args_len * sizeof(*call->args)); 4340 call->args = new_args; 4341 } 4342 call->args[call->args_len++] = arg; 4343 } 4344 4345 /* 4346 * Compare the type of an argument with the corresponding type of a 4347 * prototype parameter. If it is a valid combination, but both types 4348 * are not the same, insert a conversion to convert the argument into 4349 * the type of the parameter. 4350 */ 4351 static tnode_t * 4352 check_prototype_argument( 4353 int n, /* pos of arg */ 4354 type_t *tp, /* expected type (from prototype) */ 4355 tnode_t *tn) /* argument */ 4356 { 4357 tnode_t *ln = xcalloc(1, sizeof(*ln)); 4358 ln->tn_type = expr_unqualified_type(tp); 4359 ln->tn_lvalue = true; 4360 if (typeok(FARG, n, ln, tn)) { 4361 bool dowarn; 4362 if (!types_compatible(tp, tn->tn_type, 4363 true, false, (dowarn = false, &dowarn)) || dowarn) 4364 tn = convert(FARG, n, tp, tn); 4365 } 4366 free(ln); 4367 return tn; 4368 } 4369 4370 /* 4371 * Check types of all function arguments and insert conversions, 4372 * if necessary. 4373 */ 4374 static void 4375 check_function_arguments(const function_call *call) 4376 { 4377 type_t *ftp = call->func->tn_type->t_subt; 4378 4379 /* get # of parameters in the prototype */ 4380 int npar = 0; 4381 for (const sym_t *p = ftp->u.params; p != NULL; p = p->s_next) 4382 npar++; 4383 4384 int narg = (int)call->args_len; 4385 4386 const sym_t *param = ftp->u.params; 4387 if (ftp->t_proto && npar != narg && !(ftp->t_vararg && npar < narg)) { 4388 /* argument mismatch: %d %s passed, %d expected */ 4389 error(150, narg, narg != 1 ? "arguments" : "argument", npar); 4390 param = NULL; 4391 } 4392 4393 for (int i = 0; i < narg; i++) { 4394 tnode_t *arg = call->args[i]; 4395 4396 /* some things which are always not allowed */ 4397 tspec_t at = arg->tn_type->t_tspec; 4398 if (at == VOID) { 4399 /* void expressions may not be arguments, arg #%d */ 4400 error(151, i + 1); 4401 return; 4402 } 4403 if (is_struct_or_union(at) && is_incomplete(arg->tn_type)) { 4404 /* argument cannot have unknown size, arg #%d */ 4405 error(152, i + 1); 4406 return; 4407 } 4408 if (is_integer(at) && 4409 arg->tn_type->t_is_enum && 4410 is_incomplete(arg->tn_type)) { 4411 /* argument cannot have unknown size, arg #%d */ 4412 warning(152, i + 1); 4413 } 4414 4415 arg = cconv(arg); 4416 call->args[i] = arg; 4417 4418 arg = param != NULL 4419 ? check_prototype_argument(i + 1, param->s_type, arg) 4420 : promote(NOOP, true, arg); 4421 call->args[i] = arg; 4422 4423 if (param != NULL) 4424 param = param->s_next; 4425 } 4426 } 4427 4428 tnode_t * 4429 build_function_call(tnode_t *func, bool sys, function_call *call) 4430 { 4431 4432 if (func == NULL) 4433 return NULL; 4434 4435 call->func = func; 4436 check_ctype_function_call(call); 4437 4438 func = cconv(func); 4439 call->func = func; 4440 4441 if (func->tn_type->t_tspec != PTR || 4442 func->tn_type->t_subt->t_tspec != FUNC) { 4443 /* cannot call '%s', must be a function */ 4444 error(149, type_name(func->tn_type)); 4445 return NULL; 4446 } 4447 4448 check_function_arguments(call); 4449 4450 tnode_t *ntn = expr_alloc_tnode(); 4451 ntn->tn_op = CALL; 4452 ntn->tn_type = func->tn_type->t_subt->t_subt; 4453 ntn->tn_sys = sys; 4454 ntn->u.call = call; 4455 return ntn; 4456 } 4457 4458 /* 4459 * Return the value of an integral constant expression. 4460 * If the expression is not constant or its type is not an integer 4461 * type, an error message is printed. 4462 */ 4463 val_t * 4464 integer_constant(tnode_t *tn, bool required) 4465 { 4466 4467 if (tn != NULL) 4468 tn = cconv(tn); 4469 if (tn != NULL) 4470 tn = promote(NOOP, false, tn); 4471 4472 val_t *v = xcalloc(1, sizeof(*v)); 4473 4474 if (tn == NULL) { 4475 lint_assert(seen_error); 4476 debug_step("constant node is null; returning 1 instead"); 4477 v->v_tspec = INT; 4478 v->u.integer = 1; 4479 return v; 4480 } 4481 4482 v->v_tspec = tn->tn_type->t_tspec; 4483 4484 if (tn->tn_op == CON) { 4485 lint_assert(tn->tn_type->t_tspec == tn->u.value.v_tspec); 4486 if (is_integer(tn->u.value.v_tspec)) { 4487 v->v_unsigned_since_c90 = 4488 tn->u.value.v_unsigned_since_c90; 4489 v->u.integer = tn->u.value.u.integer; 4490 return v; 4491 } 4492 v->u.integer = (int64_t)tn->u.value.u.floating; 4493 } else 4494 v->u.integer = 1; 4495 4496 if (required) 4497 /* integral constant expression expected */ 4498 error(55); 4499 else 4500 /* variable array dimension is a C99/GCC extension */ 4501 c99ism(318); 4502 4503 if (!is_integer(v->v_tspec)) 4504 v->v_tspec = INT; 4505 4506 return v; 4507 } 4508 4509 static bool 4510 is_constcond_false(const tnode_t *tn, tspec_t t) 4511 { 4512 return (t == BOOL || t == INT) && 4513 tn->tn_op == CON && tn->u.value.u.integer == 0; 4514 } 4515 4516 /* 4517 * Perform some tests on expressions which can't be done in build_binary() 4518 * and functions called by build_binary(). These tests must be done here 4519 * because we need some information about the context in which the operations 4520 * are performed. 4521 * After all tests are performed and dofreeblk is true, expr() frees the 4522 * memory which is used for the expression. 4523 */ 4524 void 4525 expr(tnode_t *tn, bool vctx, bool cond, bool dofreeblk, bool is_do_while) 4526 { 4527 4528 if (tn == NULL) { /* in case of errors */ 4529 expr_free_all(); 4530 return; 4531 } 4532 4533 /* expr() is also called in global initializations */ 4534 if (dcs->d_kind != DLK_EXTERN && !is_do_while) 4535 check_statement_reachable(); 4536 4537 check_expr_misc(tn, vctx, cond, !cond, false, false, false); 4538 if (tn->tn_op == ASSIGN && !tn->tn_parenthesized) { 4539 if (hflag && cond) 4540 /* assignment in conditional context */ 4541 warning(159); 4542 } else if (tn->tn_op == CON) { 4543 if (hflag && cond && !suppress_constcond && 4544 !tn->tn_system_dependent && 4545 !(is_do_while && 4546 is_constcond_false(tn, tn->tn_type->t_tspec))) 4547 /* constant in conditional context */ 4548 warning(161); 4549 } 4550 if (!modtab[tn->tn_op].m_has_side_effect) { 4551 /* 4552 * for left operands of COMMA this warning is already printed 4553 */ 4554 if (tn->tn_op != COMMA && !vctx && !cond) 4555 check_null_effect(tn); 4556 } 4557 debug_node(tn); 4558 4559 if (dofreeblk) 4560 expr_free_all(); 4561 } 4562 4563 /* If the expression has the form '*(arr + idx)', check the array index. */ 4564 static void 4565 check_array_index(const tnode_t *indir, bool taking_address) 4566 { 4567 const tnode_t *plus, *arr, *idx; 4568 4569 if (indir->tn_op == INDIR 4570 && (plus = indir->u.ops.left, plus->tn_op == PLUS) 4571 && plus->u.ops.left->tn_op == ADDR 4572 && (arr = plus->u.ops.left->u.ops.left, true) 4573 && (arr->tn_op == STRING || arr->tn_op == NAME) 4574 && arr->tn_type->t_tspec == ARRAY 4575 && (idx = plus->u.ops.right, idx->tn_op == CON) 4576 && (!is_incomplete(arr->tn_type) || idx->u.value.u.integer < 0)) 4577 goto proceed; 4578 return; 4579 4580 proceed:; 4581 int elsz = length_in_bits(arr->tn_type->t_subt, NULL); 4582 if (elsz == 0) 4583 return; 4584 elsz /= CHAR_SIZE; 4585 4586 /* Change the unit of the index from bytes to element size. */ 4587 int64_t con = is_uinteger(idx->tn_type->t_tspec) 4588 ? (int64_t)((uint64_t)idx->u.value.u.integer / elsz) 4589 : idx->u.value.u.integer / elsz; 4590 4591 int dim = arr->tn_type->u.dimension + (taking_address ? 1 : 0); 4592 4593 if (!is_uinteger(idx->tn_type->t_tspec) && con < 0) 4594 /* array subscript %jd cannot be negative */ 4595 warning(167, (intmax_t)con); 4596 else if (dim > 0 && (uint64_t)con >= (uint64_t)dim) 4597 /* array subscript %ju cannot be > %d */ 4598 warning(168, (uintmax_t)con, dim - 1); 4599 } 4600 4601 static void 4602 check_expr_addr(const tnode_t *ln, bool szof, bool fcall) 4603 { 4604 /* XXX: Taking warn_about_unreachable into account here feels wrong. */ 4605 if (ln->tn_op == NAME && (reached || !warn_about_unreachable)) { 4606 if (!szof) 4607 mark_as_set(ln->u.sym); 4608 mark_as_used(ln->u.sym, fcall, szof); 4609 } 4610 check_array_index(ln, true); 4611 } 4612 4613 /* 4614 * If there is an asm statement in one of the compound statements around, 4615 * there may be other side effects, so don't warn. 4616 */ 4617 static bool 4618 is_asm_around(void) 4619 { 4620 for (decl_level *dl = dcs; dl != NULL; dl = dl->d_enclosing) 4621 if (dl->d_asm) 4622 return true; 4623 return false; 4624 } 4625 4626 static void 4627 check_expr_side_effect(const tnode_t *ln, bool szof) 4628 { 4629 4630 /* XXX: Taking warn_about_unreachable into account here feels wrong. */ 4631 if (ln->tn_op == NAME && (reached || !warn_about_unreachable)) { 4632 scl_t sc = ln->u.sym->s_scl; 4633 if (sc != EXTERN && sc != STATIC && 4634 !ln->u.sym->s_set && !szof && !is_asm_around()) { 4635 /* '%s' may be used before set */ 4636 warning(158, ln->u.sym->s_name); 4637 mark_as_set(ln->u.sym); 4638 } 4639 mark_as_used(ln->u.sym, false, false); 4640 } 4641 } 4642 4643 static void 4644 check_expr_assign(const tnode_t *ln, bool szof) 4645 { 4646 /* XXX: Taking warn_about_unreachable into account here feels wrong. */ 4647 if (ln->tn_op == NAME && !szof && (reached || !warn_about_unreachable)) { 4648 mark_as_set(ln->u.sym); 4649 if (ln->u.sym->s_scl == EXTERN) 4650 outusg(ln->u.sym); 4651 } 4652 check_array_index(ln, false); 4653 } 4654 4655 static void 4656 check_expr_call(const tnode_t *tn, const tnode_t *ln, 4657 bool szof, bool vctx, bool cond, bool retval_discarded) 4658 { 4659 lint_assert(ln->tn_op == ADDR); 4660 lint_assert(ln->u.ops.left->tn_op == NAME); 4661 if (!szof && !is_compiler_builtin(ln->u.ops.left->u.sym->s_name)) 4662 outcall(tn, vctx || cond, retval_discarded); 4663 4664 const function_call *call = tn->u.call; 4665 if (call->args_len == 4 || call->args_len == 5) 4666 check_snprintb(call); 4667 } 4668 4669 static void 4670 check_expr_op(op_t op, const tnode_t *ln, bool szof, bool fcall, bool eqwarn) 4671 { 4672 switch (op) { 4673 case ADDR: 4674 check_expr_addr(ln, szof, fcall); 4675 break; 4676 case LOAD: 4677 check_array_index(ln, false); 4678 /* FALLTHROUGH */ 4679 case INCBEF: 4680 case DECBEF: 4681 case INCAFT: 4682 case DECAFT: 4683 case ADDASS: 4684 case SUBASS: 4685 case MULASS: 4686 case DIVASS: 4687 case MODASS: 4688 case ANDASS: 4689 case ORASS: 4690 case XORASS: 4691 case SHLASS: 4692 case SHRASS: 4693 case REAL: 4694 case IMAG: 4695 check_expr_side_effect(ln, szof); 4696 break; 4697 case ASSIGN: 4698 check_expr_assign(ln, szof); 4699 break; 4700 case EQ: 4701 if (hflag && eqwarn) 4702 /* operator '==' found where '=' was expected */ 4703 warning(160); 4704 break; 4705 default: 4706 break; 4707 } 4708 } 4709 4710 /* 4711 * vctx ??? 4712 * cond whether the expression is a condition that 4713 * will be compared with 0 4714 * eqwarn whether the operator '==' might be a 4715 * misspelled '=' 4716 * fcall whether the expression is a function call 4717 * retval_discarded whether the return value of a function call 4718 * is discarded; such calls will be analyzed by 4719 * lint2 in messages 4, 8 and 9 4720 * szof whether the expression is part of a sizeof 4721 * expression, which means that its value is 4722 * discarded since only the type is relevant 4723 */ 4724 void 4725 check_expr_misc(const tnode_t *tn, bool vctx, bool cond, 4726 bool eqwarn, bool fcall, bool retval_discarded, bool szof) 4727 { 4728 4729 if (tn == NULL) 4730 return; 4731 op_t op = tn->tn_op; 4732 if (op == NAME || op == CON || op == STRING) 4733 return; 4734 bool is_direct = op == CALL 4735 && tn->u.call->func->tn_op == ADDR 4736 && tn->u.call->func->u.ops.left->tn_op == NAME; 4737 if (op == CALL) { 4738 const function_call *call = tn->u.call; 4739 if (is_direct) 4740 check_expr_call(tn, call->func, 4741 szof, vctx, cond, retval_discarded); 4742 bool discard = op == CVT && tn->tn_type->t_tspec == VOID; 4743 check_expr_misc(call->func, false, false, false, is_direct, 4744 discard, szof); 4745 for (size_t i = 0, n = call->args_len; i < n; i++) 4746 check_expr_misc(call->args[i], 4747 true, false, false, false, false, szof); 4748 return; 4749 } 4750 4751 lint_assert(has_operands(tn)); 4752 tnode_t *ln = tn->u.ops.left; 4753 tnode_t *rn = tn->u.ops.right; 4754 check_expr_op(op, ln, szof, fcall, eqwarn); 4755 4756 const mod_t *mp = &modtab[op]; 4757 bool cvctx = mp->m_value_context; 4758 bool ccond = mp->m_compares_with_zero; 4759 bool eq = mp->m_warn_if_operand_eq && 4760 !ln->tn_parenthesized && 4761 rn != NULL && !rn->tn_parenthesized; 4762 4763 /* 4764 * Values of operands of ':' are not used if the type of at least 4765 * one of the operands (for GCC compatibility) is 'void'. 4766 * 4767 * XXX test/value context of QUEST should probably be used as 4768 * context for both operands of COLON. 4769 */ 4770 if (op == COLON && tn->tn_type->t_tspec == VOID) 4771 cvctx = ccond = false; 4772 bool discard = op == CVT && tn->tn_type->t_tspec == VOID; 4773 check_expr_misc(ln, cvctx, ccond, eq, is_direct, discard, szof); 4774 4775 switch (op) { 4776 case LOGAND: 4777 case LOGOR: 4778 check_expr_misc(rn, false, true, eq, false, false, szof); 4779 break; 4780 case COLON: 4781 check_expr_misc(rn, cvctx, ccond, eq, false, false, szof); 4782 break; 4783 case COMMA: 4784 check_expr_misc(rn, vctx, cond, false, false, false, szof); 4785 break; 4786 default: 4787 if (mp->m_binary) 4788 check_expr_misc(rn, true, false, eq, false, false, 4789 szof); 4790 break; 4791 } 4792 } 4793 4794 /* 4795 * Return whether the expression can be used for static initialization. 4796 * 4797 * Constant initialization expressions must be constant or an address 4798 * of a static object with an optional offset. In the first case, 4799 * the result is returned in *offsp. In the second case, the static 4800 * object is returned in *symp and the offset in *offsp. 4801 * 4802 * The expression can consist of PLUS, MINUS, ADDR, NAME, STRING and 4803 * CON. Type conversions are allowed if they do not change binary 4804 * representation (including width). 4805 * 4806 * C99 6.6 "Constant expressions" 4807 * C99 6.7.8p4 restricts initializers for static storage duration 4808 */ 4809 bool 4810 constant_addr(const tnode_t *tn, const sym_t **symp, ptrdiff_t *offsp) 4811 { 4812 const sym_t *sym; 4813 ptrdiff_t offs1, offs2; 4814 tspec_t t, ot; 4815 4816 switch (tn->tn_op) { 4817 case MINUS: 4818 if (tn->u.ops.right->tn_op == CVT) 4819 return constant_addr(tn->u.ops.right, symp, offsp); 4820 else if (tn->u.ops.right->tn_op != CON) 4821 return false; 4822 /* FALLTHROUGH */ 4823 case PLUS: 4824 offs1 = offs2 = 0; 4825 if (tn->u.ops.left->tn_op == CON) { 4826 offs1 = (ptrdiff_t)tn->u.ops.left->u.value.u.integer; 4827 if (!constant_addr(tn->u.ops.right, &sym, &offs2)) 4828 return false; 4829 } else if (tn->u.ops.right->tn_op == CON) { 4830 offs2 = (ptrdiff_t)tn->u.ops.right->u.value.u.integer; 4831 if (tn->tn_op == MINUS) 4832 offs2 = -offs2; 4833 if (!constant_addr(tn->u.ops.left, &sym, &offs1)) 4834 return false; 4835 } else { 4836 return false; 4837 } 4838 *symp = sym; 4839 *offsp = offs1 + offs2; 4840 return true; 4841 case ADDR: 4842 if (tn->u.ops.left->tn_op == NAME) { 4843 *symp = tn->u.ops.left->u.sym; 4844 *offsp = 0; 4845 return true; 4846 } else { 4847 /* 4848 * If this were the front end of a compiler, we would 4849 * return a label instead of 0, at least if 4850 * 'tn->u.ops.left->tn_op == STRING'. 4851 */ 4852 *symp = NULL; 4853 *offsp = 0; 4854 return true; 4855 } 4856 case CVT: 4857 t = tn->tn_type->t_tspec; 4858 ot = tn->u.ops.left->tn_type->t_tspec; 4859 if ((!is_integer(t) && t != PTR) || 4860 (!is_integer(ot) && ot != PTR)) { 4861 return false; 4862 } 4863 #if 0 4864 /*- 4865 * consider: 4866 * struct foo { 4867 * unsigned char a; 4868 * } f = { 4869 * (unsigned char)(unsigned long) 4870 * (&(((struct foo *)0)->a)) 4871 * }; 4872 * since psize(unsigned long) != psize(unsigned char), 4873 * this fails. 4874 */ 4875 else if (psize(t) != psize(ot)) 4876 return -1; 4877 #endif 4878 return constant_addr(tn->u.ops.left, symp, offsp); 4879 default: 4880 return false; 4881 } 4882 } 4883 4884 /* Append s2 to s1, then free s2. */ 4885 buffer * 4886 cat_strings(buffer *s1, buffer *s2) 4887 { 4888 4889 if ((s1->data != NULL) != (s2->data != NULL)) { 4890 /* cannot concatenate wide and regular string literals */ 4891 error(292); 4892 return s1; 4893 } 4894 4895 if (s1->data != NULL) { 4896 while (s1->len + s2->len + 1 > s1->cap) 4897 s1->cap *= 2; 4898 s1->data = xrealloc(s1->data, s1->cap); 4899 memcpy(s1->data + s1->len, s2->data, s2->len + 1); 4900 free(s2->data); 4901 } 4902 s1->len += s2->len; 4903 free(s2); 4904 4905 return s1; 4906 } 4907 4908 4909 typedef struct stmt_expr { 4910 memory_pool se_mem; 4911 sym_t *se_sym; 4912 struct stmt_expr *se_enclosing; 4913 } stmt_expr; 4914 4915 static stmt_expr *stmt_exprs; 4916 4917 void 4918 begin_statement_expr(void) 4919 { 4920 debug_enter(); 4921 4922 stmt_expr *se = xmalloc(sizeof(*se)); 4923 se->se_mem = expr_save_memory(); 4924 se->se_sym = NULL; 4925 se->se_enclosing = stmt_exprs; 4926 stmt_exprs = se; 4927 } 4928 4929 void 4930 do_statement_expr(tnode_t *tn) 4931 { 4932 block_level--; 4933 mem_block_level--; 4934 stmt_exprs->se_sym = tn != NULL 4935 ? mktempsym(block_dup_type(tn->tn_type)) 4936 : NULL; /* after a syntax error */ 4937 mem_block_level++; 4938 block_level++; 4939 /* '({ ... })' is a GCC extension */ 4940 gnuism(320); 4941 } 4942 4943 tnode_t * 4944 end_statement_expr(void) 4945 { 4946 tnode_t *tn; 4947 4948 stmt_expr *se = stmt_exprs; 4949 if (se->se_sym == NULL) { 4950 tn = NULL; /* after a syntax error */ 4951 goto end; 4952 } 4953 4954 tn = build_name(se->se_sym, false); 4955 (void)expr_save_memory(); /* leak */ 4956 expr_restore_memory(se->se_mem); 4957 stmt_exprs = se->se_enclosing; 4958 free(se); 4959 4960 end: 4961 debug_leave(); 4962 return tn; 4963 } 4964 4965 bool 4966 in_statement_expr(void) 4967 { 4968 return stmt_exprs != NULL; 4969 } 4970
Indexes created Wed Sep 24 05:09:52 GMT 2025