tree.c revision 1.635
1 /* $NetBSD: tree.c,v 1.635 2024/04/12 05:44:38 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 1.635 2024/04/12 05:44:38 rillig Exp $"); 41 #endif 42 43 #include <float.h> 44 #include <limits.h> 45 #include <math.h> 46 #include <signal.h> 47 #include <stdlib.h> 48 #include <string.h> 49 50 #include "lint1.h" 51 52 53 typedef struct integer_constraints { 54 int64_t smin; /* signed minimum */ 55 int64_t smax; /* signed maximum */ 56 uint64_t umin; /* unsigned minimum */ 57 uint64_t umax; /* unsigned maximum */ 58 uint64_t bset; /* bits that are definitely set */ 59 uint64_t bclr; /* bits that are definitely clear */ 60 } integer_constraints; 61 62 63 static uint64_t 64 u64_fill_right(uint64_t x) 65 { 66 x |= x >> 1; 67 x |= x >> 2; 68 x |= x >> 4; 69 x |= x >> 8; 70 x |= x >> 16; 71 x |= x >> 32; 72 return x; 73 } 74 75 static bool 76 str_ends_with(const char *haystack, const char *needle) 77 { 78 size_t hlen = strlen(haystack); 79 size_t nlen = strlen(needle); 80 81 return nlen <= hlen && 82 memcmp(haystack + hlen - nlen, needle, nlen) == 0; 83 } 84 85 static unsigned 86 width_in_bits(const type_t *tp) 87 { 88 89 lint_assert(is_integer(tp->t_tspec)); 90 return tp->t_bitfield 91 ? tp->t_bit_field_width 92 : size_in_bits(tp->t_tspec); 93 } 94 95 static int 96 portable_rank_cmp(tspec_t t1, tspec_t t2) 97 { 98 const ttab_t *p1 = type_properties(t1), *p2 = type_properties(t2); 99 lint_assert(p1->tt_rank_kind == p2->tt_rank_kind); 100 lint_assert(p1->tt_rank_value > 0); 101 lint_assert(p2->tt_rank_value > 0); 102 return (int)p1->tt_rank_value - (int)p2->tt_rank_value; 103 } 104 105 static bool 106 ic_maybe_signed(const type_t *tp, const integer_constraints *ic) 107 { 108 return !is_uinteger(tp->t_tspec) && ic->bclr >> 63 == 0; 109 } 110 111 static integer_constraints 112 ic_any(const type_t *tp) 113 { 114 integer_constraints c; 115 116 uint64_t vbits = value_bits(width_in_bits(tp)); 117 if (is_uinteger(tp->t_tspec)) { 118 c.smin = INT64_MIN; 119 c.smax = INT64_MAX; 120 c.umin = 0; 121 c.umax = vbits; 122 c.bset = 0; 123 c.bclr = ~c.umax; 124 } else { 125 c.smin = (int64_t)-1 - (int64_t)(vbits >> 1); 126 c.smax = (int64_t)(vbits >> 1); 127 c.umin = 0; 128 c.umax = UINT64_MAX; 129 c.bset = 0; 130 c.bclr = 0; 131 } 132 return c; 133 } 134 135 static integer_constraints 136 ic_con(const type_t *tp, const val_t *v) 137 { 138 integer_constraints c; 139 140 lint_assert(is_integer(tp->t_tspec)); 141 int64_t si = v->u.integer; 142 uint64_t ui = (uint64_t)si; 143 c.smin = si; 144 c.smax = si; 145 c.umin = ui; 146 c.umax = ui; 147 c.bset = ui; 148 c.bclr = ~ui; 149 return c; 150 } 151 152 static integer_constraints 153 ic_cvt(const type_t *ntp, const type_t *otp, integer_constraints a) 154 { 155 unsigned nw = width_in_bits(ntp); 156 unsigned ow = width_in_bits(otp); 157 bool nu = is_uinteger(ntp->t_tspec); 158 bool ou = is_uinteger(otp->t_tspec); 159 160 if (nw >= ow && nu == ou) 161 return a; 162 if (nw > ow && ou) 163 return a; 164 return ic_any(ntp); 165 } 166 167 static integer_constraints 168 ic_bitand(integer_constraints a, integer_constraints b) 169 { 170 integer_constraints c; 171 172 c.smin = INT64_MIN; 173 c.smax = INT64_MAX; 174 c.umin = 0; 175 c.umax = UINT64_MAX; 176 c.bset = a.bset & b.bset; 177 c.bclr = a.bclr | b.bclr; 178 return c; 179 } 180 181 static integer_constraints 182 ic_bitor(integer_constraints a, integer_constraints b) 183 { 184 integer_constraints c; 185 186 c.smin = INT64_MIN; 187 c.smax = INT64_MAX; 188 c.umin = 0; 189 c.umax = UINT64_MAX; 190 c.bset = a.bset | b.bset; 191 c.bclr = a.bclr & b.bclr; 192 return c; 193 } 194 195 static integer_constraints 196 ic_mod(const type_t *tp, integer_constraints a, integer_constraints b) 197 { 198 integer_constraints c; 199 200 if (ic_maybe_signed(tp, &a) || ic_maybe_signed(tp, &b)) 201 return ic_any(tp); 202 203 c.smin = INT64_MIN; 204 c.smax = INT64_MAX; 205 c.umin = 0; 206 c.umax = b.umax - 1; 207 c.bset = 0; 208 c.bclr = ~u64_fill_right(c.umax); 209 return c; 210 } 211 212 static integer_constraints 213 ic_shl(const type_t *tp, integer_constraints a, integer_constraints b) 214 { 215 integer_constraints c; 216 unsigned int amount; 217 218 if (ic_maybe_signed(tp, &a)) 219 return ic_any(tp); 220 221 if (b.smin == b.smax && b.smin >= 0 && b.smin < 64) 222 amount = (unsigned int)b.smin; 223 else if (b.umin == b.umax && b.umin < 64) 224 amount = (unsigned int)b.umin; 225 else 226 return ic_any(tp); 227 228 c.smin = INT64_MIN; 229 c.smax = INT64_MAX; 230 c.umin = 0; 231 c.umax = UINT64_MAX; 232 c.bset = a.bset << amount; 233 c.bclr = a.bclr << amount | (((uint64_t)1 << amount) - 1); 234 return c; 235 } 236 237 static integer_constraints 238 ic_shr(const type_t *tp, integer_constraints a, integer_constraints b) 239 { 240 integer_constraints c; 241 unsigned int amount; 242 243 if (ic_maybe_signed(tp, &a)) 244 return ic_any(tp); 245 246 if (b.smin == b.smax && b.smin >= 0 && b.smin < 64) 247 amount = (unsigned int)b.smin; 248 else if (b.umin == b.umax && b.umin < 64) 249 amount = (unsigned int)b.umin; 250 else 251 return ic_any(tp); 252 253 c.smin = INT64_MIN; 254 c.smax = INT64_MAX; 255 c.umin = 0; 256 c.umax = UINT64_MAX; 257 c.bset = a.bset >> amount; 258 c.bclr = a.bclr >> amount | ~(~(uint64_t)0 >> amount); 259 return c; 260 } 261 262 static integer_constraints 263 ic_cond(integer_constraints a, integer_constraints b) 264 { 265 integer_constraints c; 266 267 c.smin = a.smin < b.smin ? a.smin : b.smin; 268 c.smax = a.smax > b.smax ? a.smax : b.smax; 269 c.umin = a.umin < b.umin ? a.umin : b.umin; 270 c.umax = a.umax > b.umax ? a.umax : b.umax; 271 c.bset = a.bset | b.bset; 272 c.bclr = a.bclr & b.bclr; 273 return c; 274 } 275 276 static integer_constraints 277 ic_expr(const tnode_t *tn) 278 { 279 integer_constraints lc, rc; 280 281 lint_assert(is_integer(tn->tn_type->t_tspec)); 282 283 switch (tn->tn_op) { 284 case CON: 285 return ic_con(tn->tn_type, &tn->u.value); 286 case CVT: 287 if (!is_integer(tn->u.ops.left->tn_type->t_tspec)) 288 return ic_any(tn->tn_type); 289 lc = ic_expr(tn->u.ops.left); 290 return ic_cvt(tn->tn_type, tn->u.ops.left->tn_type, lc); 291 case MOD: 292 lc = ic_expr(before_conversion(tn->u.ops.left)); 293 rc = ic_expr(before_conversion(tn->u.ops.right)); 294 return ic_mod(tn->tn_type, lc, rc); 295 case SHL: 296 lc = ic_expr(tn->u.ops.left); 297 rc = ic_expr(tn->u.ops.right); 298 return ic_shl(tn->tn_type, lc, rc); 299 case SHR: 300 lc = ic_expr(tn->u.ops.left); 301 rc = ic_expr(tn->u.ops.right); 302 return ic_shr(tn->tn_type, lc, rc); 303 case BITAND: 304 lc = ic_expr(tn->u.ops.left); 305 rc = ic_expr(tn->u.ops.right); 306 return ic_bitand(lc, rc); 307 case BITOR: 308 lc = ic_expr(tn->u.ops.left); 309 rc = ic_expr(tn->u.ops.right); 310 return ic_bitor(lc, rc); 311 case QUEST: 312 lc = ic_expr(tn->u.ops.right->u.ops.left); 313 rc = ic_expr(tn->u.ops.right->u.ops.right); 314 return ic_cond(lc, rc); 315 default: 316 return ic_any(tn->tn_type); 317 } 318 } 319 320 uint64_t 321 possible_bits(const tnode_t *tn) 322 { 323 return ~ic_expr(tn).bclr; 324 } 325 326 /* Build 'pointer to tp', 'array of tp' or 'function returning tp'. */ 327 type_t * 328 block_derive_type(type_t *tp, tspec_t t) 329 { 330 331 type_t *tp2 = block_zero_alloc(sizeof(*tp2), "type"); 332 tp2->t_tspec = t; 333 tp2->t_subt = tp; 334 return tp2; 335 } 336 337 /* 338 * Derive 'pointer to tp' or 'function returning tp'. 339 * The memory is freed at the end of the current expression. 340 */ 341 type_t * 342 expr_derive_type(type_t *tp, tspec_t t) 343 { 344 345 type_t *tp2 = expr_zero_alloc(sizeof(*tp2), "type"); 346 tp2->t_tspec = t; 347 tp2->t_subt = tp; 348 return tp2; 349 } 350 351 /* Create an expression from a unary or binary operator and its operands. */ 352 static tnode_t * 353 build_op(op_t op, bool sys, type_t *type, tnode_t *ln, tnode_t *rn) 354 { 355 356 tnode_t *ntn = expr_alloc_tnode(); 357 ntn->tn_op = op; 358 ntn->tn_type = type; 359 ntn->tn_sys = sys; 360 ntn->u.ops.left = ln; 361 ntn->u.ops.right = rn; 362 363 if (op == INDIR || op == FSEL) { 364 lint_assert(ln->tn_type->t_tspec == PTR); 365 tspec_t t = ln->tn_type->t_subt->t_tspec; 366 ntn->tn_lvalue = t != FUNC && t != VOID; 367 } 368 369 return ntn; 370 } 371 372 tnode_t * 373 build_constant(type_t *tp, val_t *v) 374 { 375 376 tnode_t *n = expr_alloc_tnode(); 377 n->tn_op = CON; 378 n->tn_type = tp; 379 n->u.value = *v; 380 n->u.value.v_tspec = tp->t_tspec; 381 free(v); 382 return n; 383 } 384 385 static tnode_t * 386 build_integer_constant(tspec_t t, int64_t si) 387 { 388 389 tnode_t *n = expr_alloc_tnode(); 390 n->tn_op = CON; 391 n->tn_type = gettyp(t); 392 n->u.value.v_tspec = t; 393 n->u.value.v_unsigned_since_c90 = false; 394 n->u.value.v_char_constant = false; 395 n->u.value.u.integer = si; 396 return n; 397 } 398 399 static void 400 fallback_symbol(sym_t *sym) 401 { 402 403 if (Tflag && fallback_symbol_strict_bool(sym)) 404 return; 405 406 if (block_level > 0 && (strcmp(sym->s_name, "__FUNCTION__") == 0 || 407 strcmp(sym->s_name, "__PRETTY_FUNCTION__") == 0)) { 408 /* __FUNCTION__/__PRETTY_FUNCTION__ is a GCC extension */ 409 gnuism(316); 410 // XXX: Should probably be ARRAY instead of PTR. 411 sym->s_type = block_derive_type(gettyp(CHAR), PTR); 412 sym->s_type->t_const = true; 413 return; 414 } 415 416 if (funcsym != NULL && strcmp(sym->s_name, "__func__") == 0) { 417 if (!allow_c99) 418 /* __func__ is a C99 feature */ 419 warning(317); 420 /* C11 6.4.2.2 */ 421 sym->s_type = block_derive_type(gettyp(CHAR), ARRAY); 422 sym->s_type->t_const = true; 423 sym->s_type->u.dimension = (int)strlen(funcsym->s_name) + 1; 424 return; 425 } 426 427 /* '%s' undefined */ 428 error(99, sym->s_name); 429 } 430 431 /* 432 * Functions that are predeclared by GCC or other compilers can be called 433 * with arbitrary arguments. Since lint usually runs after a successful 434 * compilation, it's the compiler's job to catch any errors. 435 */ 436 bool 437 is_compiler_builtin(const char *name) 438 { 439 /* https://gcc.gnu.org/onlinedocs/gcc/C-Extensions.html */ 440 if (allow_gcc) { 441 if (strncmp(name, "__atomic_", 9) == 0 || 442 strncmp(name, "__builtin_", 10) == 0 || 443 strcmp(name, "alloca") == 0 || 444 /* obsolete but still in use, as of 2021 */ 445 strncmp(name, "__sync_", 7) == 0) 446 return true; 447 } 448 449 /* https://software.intel.com/sites/landingpage/IntrinsicsGuide/ */ 450 if (strncmp(name, "_mm_", 4) == 0) 451 return true; 452 453 return false; 454 } 455 456 /* https://gcc.gnu.org/onlinedocs/gcc/Integer-Overflow-Builtins.html */ 457 static bool 458 is_gcc_bool_builtin(const char *name) 459 { 460 return strncmp(name, "__builtin_", 10) == 0 && 461 (str_ends_with(name, "_overflow") || 462 str_ends_with(name, "_overflow_p")); 463 } 464 465 static void 466 build_name_call(sym_t *sym) 467 { 468 469 if (is_compiler_builtin(sym->s_name)) { 470 /* 471 * Do not warn about these, just assume that they are regular 472 * functions compatible with non-prototype calling conventions. 473 */ 474 if (allow_gcc && is_gcc_bool_builtin(sym->s_name)) 475 sym->s_type = gettyp(BOOL); 476 } else if (allow_c99) 477 /* function '%s' implicitly declared to return int */ 478 error(215, sym->s_name); 479 else if (!allow_trad) 480 /* function '%s' implicitly declared to return int */ 481 warning(215, sym->s_name); 482 483 /* XXX if !allow_c90, the symbol should be exported to level 0 */ 484 sym->s_type = block_derive_type(sym->s_type, FUNC); 485 } 486 487 /* Create a node for a name (symbol table entry). */ 488 tnode_t * 489 build_name(sym_t *sym, bool is_funcname) 490 { 491 492 if (sym->s_scl == NO_SCL && !in_gcc_attribute) { 493 sym->s_scl = EXTERN; 494 sym->s_def = DECL; 495 if (is_funcname) 496 build_name_call(sym); 497 else 498 fallback_symbol(sym); 499 } 500 501 lint_assert(sym->s_kind == SK_VCFT || sym->s_kind == SK_MEMBER); 502 503 tnode_t *n = expr_alloc_tnode(); 504 n->tn_type = sym->s_type; 505 if (sym->s_scl == BOOL_CONST) { 506 n->tn_op = CON; 507 n->u.value.v_tspec = BOOL; 508 n->u.value.v_unsigned_since_c90 = false; 509 n->u.value.v_char_constant = false; 510 n->u.value.u.integer = sym->u.s_bool_constant ? 1 : 0; 511 } else if (sym->s_scl == ENUM_CONST) { 512 n->tn_op = CON; 513 n->u.value.v_tspec = INT; /* ENUM is in n->tn_type */ 514 n->u.value.v_unsigned_since_c90 = false; 515 n->u.value.v_char_constant = false; 516 n->u.value.u.integer = sym->u.s_enum_constant; 517 } else { 518 n->tn_op = NAME; 519 n->u.sym = sym; 520 if (sym->s_kind == SK_VCFT && sym->s_type->t_tspec != FUNC) 521 n->tn_lvalue = true; 522 } 523 524 return n; 525 } 526 527 tnode_t * 528 build_string(buffer *lit) 529 { 530 size_t value_len = lit->len; 531 if (lit->data != NULL) { 532 quoted_iterator it = { .end = 0 }; 533 for (value_len = 0; quoted_next(lit, &it); value_len++) 534 continue; 535 } 536 537 type_t *tp = expr_zero_alloc(sizeof(*tp), "type"); 538 tp->t_tspec = ARRAY; 539 tp->t_subt = gettyp(lit->data != NULL ? CHAR : WCHAR_TSPEC); 540 tp->u.dimension = (int)(value_len + 1); 541 542 tnode_t *n = expr_alloc_tnode(); 543 n->tn_op = STRING; 544 n->tn_type = tp; 545 n->tn_lvalue = true; 546 547 n->u.str_literals = expr_zero_alloc(sizeof(*n->u.str_literals), "tnode.string"); 548 n->u.str_literals->len = lit->len; 549 550 if (lit->data != NULL) { 551 n->u.str_literals->data = expr_zero_alloc(lit->len + 1, 552 "tnode.string.data"); 553 (void)memcpy(n->u.str_literals->data, lit->data, lit->len + 1); 554 free(lit->data); 555 } 556 free(lit); 557 558 return n; 559 } 560 561 tnode_t * 562 build_generic_selection(const tnode_t *expr, 563 struct generic_association *sel) 564 { 565 tnode_t *default_result = NULL; 566 567 for (; sel != NULL; sel = sel->ga_prev) { 568 if (expr != NULL && 569 types_compatible(sel->ga_arg, expr->tn_type, 570 false, false, NULL)) 571 return sel->ga_result; 572 else if (sel->ga_arg == NULL) 573 default_result = sel->ga_result; 574 } 575 return default_result; 576 } 577 578 static bool 579 is_out_of_char_range(const tnode_t *tn) 580 { 581 return tn->tn_op == CON && 582 !tn->u.value.v_char_constant && 583 !(0 <= tn->u.value.u.integer && 584 tn->u.value.u.integer < 1 << (CHAR_SIZE - 1)); 585 } 586 587 static bool 588 check_nonportable_char_comparison(op_t op, 589 const tnode_t *ln, tspec_t lt, 590 const tnode_t *rn, tspec_t rt) 591 { 592 if (!(hflag || pflag)) 593 return true; 594 595 if (lt == CHAR && is_out_of_char_range(rn)) { 596 char buf[128]; 597 (void)snprintf(buf, sizeof(buf), "%s %d", 598 op_name(op), (int)rn->u.value.u.integer); 599 /* nonportable character comparison '%s' */ 600 warning(230, buf); 601 return false; 602 } 603 if (rt == CHAR && is_out_of_char_range(ln)) { 604 char buf[128]; 605 (void)snprintf(buf, sizeof(buf), "%d %s ?", 606 (int)ln->u.value.u.integer, op_name(op)); 607 /* nonportable character comparison '%s' */ 608 warning(230, buf); 609 return false; 610 } 611 return true; 612 } 613 614 static void 615 check_integer_comparison(op_t op, tnode_t *ln, tnode_t *rn) 616 { 617 618 tspec_t lt = ln->tn_type->t_tspec; 619 tspec_t rt = rn->tn_type->t_tspec; 620 621 if (ln->tn_op != CON && rn->tn_op != CON) 622 return; 623 624 if (!is_integer(lt) || !is_integer(rt)) 625 return; 626 627 if (any_query_enabled && !in_system_header) { 628 if (lt == CHAR && rn->tn_op == CON && 629 !rn->u.value.v_char_constant) { 630 /* comparison '%s' of 'char' with plain integer %d */ 631 query_message(14, 632 op_name(op), (int)rn->u.value.u.integer); 633 } 634 if (rt == CHAR && ln->tn_op == CON && 635 !ln->u.value.v_char_constant) { 636 /* comparison '%s' of 'char' with plain integer %d */ 637 query_message(14, 638 op_name(op), (int)ln->u.value.u.integer); 639 } 640 } 641 642 if (!check_nonportable_char_comparison(op, ln, lt, rn, rt)) 643 return; 644 645 if (is_uinteger(lt) && !is_uinteger(rt) && 646 rn->tn_op == CON && rn->u.value.u.integer <= 0) { 647 if (rn->u.value.u.integer < 0) { 648 /* operator '%s' compares '%s' with '%s' */ 649 warning(162, op_name(op), 650 type_name(ln->tn_type), "negative constant"); 651 } else if (op == LT || op == GE) 652 /* operator '%s' compares '%s' with '%s' */ 653 warning(162, op_name(op), type_name(ln->tn_type), "0"); 654 return; 655 } 656 if (is_uinteger(rt) && !is_uinteger(lt) && 657 ln->tn_op == CON && ln->u.value.u.integer <= 0) { 658 if (ln->u.value.u.integer < 0) { 659 /* operator '%s' compares '%s' with '%s' */ 660 warning(162, op_name(op), 661 "negative constant", type_name(rn->tn_type)); 662 } else if (op == GT || op == LE) 663 /* operator '%s' compares '%s' with '%s' */ 664 warning(162, op_name(op), "0", type_name(rn->tn_type)); 665 return; 666 } 667 } 668 669 static const tspec_t arith_rank[] = { 670 LDOUBLE, DOUBLE, FLOAT, 671 #ifdef INT128_SIZE 672 UINT128, INT128, 673 #endif 674 ULLONG, LLONG, 675 ULONG, LONG, 676 UINT, INT, 677 }; 678 679 /* Keep unsigned in traditional C */ 680 static tspec_t 681 usual_arithmetic_conversion_trad(tspec_t lt, tspec_t rt) 682 { 683 684 size_t i; 685 for (i = 0; arith_rank[i] != INT; i++) 686 if (lt == arith_rank[i] || rt == arith_rank[i]) 687 break; 688 689 tspec_t t = arith_rank[i]; 690 if (is_uinteger(lt) || is_uinteger(rt)) 691 if (is_integer(t) && !is_uinteger(t)) 692 return unsigned_type(t); 693 return t; 694 } 695 696 static tspec_t 697 usual_arithmetic_conversion_c90(tspec_t lt, tspec_t rt) 698 { 699 700 if (lt == rt) 701 return lt; 702 703 if (lt == LCOMPLEX || rt == LCOMPLEX) 704 return LCOMPLEX; 705 if (lt == DCOMPLEX || rt == DCOMPLEX) 706 return DCOMPLEX; 707 if (lt == FCOMPLEX || rt == FCOMPLEX) 708 return FCOMPLEX; 709 if (lt == LDOUBLE || rt == LDOUBLE) 710 return LDOUBLE; 711 if (lt == DOUBLE || rt == DOUBLE) 712 return DOUBLE; 713 if (lt == FLOAT || rt == FLOAT) 714 return FLOAT; 715 716 if (size_in_bits(lt) > size_in_bits(rt)) 717 return lt; 718 if (size_in_bits(lt) < size_in_bits(rt)) 719 return rt; 720 721 size_t i; 722 for (i = 3; arith_rank[i] != INT; i++) 723 if (arith_rank[i] == lt || arith_rank[i] == rt) 724 break; 725 if ((is_uinteger(lt) || is_uinteger(rt)) && 726 !is_uinteger(arith_rank[i])) 727 i--; 728 return arith_rank[i]; 729 } 730 731 static tnode_t * 732 apply_usual_arithmetic_conversions(op_t op, tnode_t *tn, tspec_t t) 733 { 734 type_t *ntp = expr_dup_type(tn->tn_type); 735 ntp->t_tspec = t; 736 if (tn->tn_op != CON) { 737 /* usual arithmetic conversion for '%s' from '%s' to '%s' */ 738 query_message(4, op_name(op), 739 type_name(tn->tn_type), type_name(ntp)); 740 } 741 return convert(op, 0, ntp, tn); 742 } 743 744 /* 745 * Apply the "usual arithmetic conversions" (C99 6.3.1.8), which gives both 746 * operands the same type. 747 */ 748 static void 749 balance(op_t op, tnode_t **lnp, tnode_t **rnp) 750 { 751 752 tspec_t lt = (*lnp)->tn_type->t_tspec; 753 tspec_t rt = (*rnp)->tn_type->t_tspec; 754 if (!is_arithmetic(lt) || !is_arithmetic(rt)) 755 return; 756 757 tspec_t t = allow_c90 758 ? usual_arithmetic_conversion_c90(lt, rt) 759 : usual_arithmetic_conversion_trad(lt, rt); 760 761 if (t != lt) 762 *lnp = apply_usual_arithmetic_conversions(op, *lnp, t); 763 if (t != rt) 764 *rnp = apply_usual_arithmetic_conversions(op, *rnp, t); 765 766 unsigned lw = (*lnp)->tn_type->t_bit_field_width; 767 unsigned rw = (*rnp)->tn_type->t_bit_field_width; 768 if (lw < rw) 769 *lnp = convert(NOOP, 0, (*rnp)->tn_type, *lnp); 770 if (rw < lw) 771 *rnp = convert(NOOP, 0, (*lnp)->tn_type, *rnp); 772 } 773 774 static tnode_t * 775 build_address(bool sys, tnode_t *tn, bool force) 776 { 777 tspec_t t; 778 779 if (!force && ((t = tn->tn_type->t_tspec) == ARRAY || t == FUNC)) { 780 if (!allow_c90) 781 /* '&' before array or function: ignored */ 782 warning(127); 783 return tn; 784 } 785 786 /* eliminate '&*' */ 787 if (tn->tn_op == INDIR && 788 tn->u.ops.left->tn_type->t_tspec == PTR && 789 tn->u.ops.left->tn_type->t_subt == tn->tn_type) { 790 return tn->u.ops.left; 791 } 792 793 return build_op(ADDR, sys, expr_derive_type(tn->tn_type, PTR), 794 tn, NULL); 795 } 796 797 static uint64_t 798 fold_unsigned_integer(op_t op, uint64_t l, uint64_t r, 799 uint64_t max_value, bool *overflow) 800 { 801 switch (op) { 802 case COMPL: 803 return ~l & max_value; 804 case UPLUS: 805 return +l; 806 case UMINUS: 807 return -l & max_value; 808 case MULT: 809 *overflow = r > 0 && l > max_value / r; 810 return l * r; 811 case DIV: 812 if (r == 0) { 813 /* division by 0 */ 814 error(139); 815 return max_value; 816 } 817 return l / r; 818 case MOD: 819 if (r == 0) { 820 /* modulus by 0 */ 821 error(140); 822 return 0; 823 } 824 return l % r; 825 case PLUS: 826 *overflow = l > max_value - r; 827 return l + r; 828 case MINUS: 829 *overflow = l < r; 830 return l - r; 831 case SHL: 832 /* TODO: warn about out-of-bounds 'r'. */ 833 /* TODO: warn about overflow. */ 834 return l << (r & 63); 835 case SHR: 836 /* TODO: warn about out-of-bounds 'r'. */ 837 return l >> (r & 63); 838 case LT: 839 return l < r ? 1 : 0; 840 case LE: 841 return l <= r ? 1 : 0; 842 case GT: 843 return l > r ? 1 : 0; 844 case GE: 845 return l >= r ? 1 : 0; 846 case EQ: 847 return l == r ? 1 : 0; 848 case NE: 849 return l != r ? 1 : 0; 850 case BITAND: 851 return l & r; 852 case BITXOR: 853 return l ^ r; 854 case BITOR: 855 return l | r; 856 default: 857 lint_assert(/*CONSTCOND*/false); 858 /* NOTREACHED */ 859 } 860 } 861 862 static int64_t 863 fold_signed_integer(op_t op, int64_t l, int64_t r, 864 int64_t min_value, int64_t max_value, bool *overflow) 865 { 866 switch (op) { 867 case COMPL: 868 return ~l; 869 case UPLUS: 870 return +l; 871 case UMINUS: 872 *overflow = l == min_value; 873 return *overflow ? l : -l; 874 case MULT:; 875 uint64_t al = l >= 0 ? (uint64_t)l : -(uint64_t)l; 876 uint64_t ar = r >= 0 ? (uint64_t)r : -(uint64_t)r; 877 bool neg = (l >= 0) != (r >= 0); 878 uint64_t max_prod = (uint64_t)max_value + (neg ? 1 : 0); 879 if (al > 0 && ar > max_prod / al) { 880 *overflow = true; 881 return neg ? min_value : max_value; 882 } 883 return l * r; 884 case DIV: 885 if (r == 0) { 886 /* division by 0 */ 887 error(139); 888 return max_value; 889 } 890 if (l == min_value && r == -1) { 891 *overflow = true; 892 return l; 893 } 894 return l / r; 895 case MOD: 896 if (r == 0) { 897 /* modulus by 0 */ 898 error(140); 899 return 0; 900 } 901 if (l == min_value && r == -1) { 902 *overflow = true; 903 return 0; 904 } 905 return l % r; 906 case PLUS: 907 if (r > 0 && l > max_value - r) { 908 *overflow = true; 909 return max_value; 910 } 911 if (r < 0 && l < min_value - r) { 912 *overflow = true; 913 return min_value; 914 } 915 return l + r; 916 case MINUS: 917 if (r > 0 && l < min_value + r) { 918 *overflow = true; 919 return min_value; 920 } 921 if (r < 0 && l > max_value + r) { 922 *overflow = true; 923 return max_value; 924 } 925 return l - r; 926 case SHL: 927 /* TODO: warn about out-of-bounds 'r'. */ 928 /* TODO: warn about overflow. */ 929 return l << (r & 63); 930 case SHR: 931 /* TODO: warn about out-of-bounds 'r'. */ 932 if (l < 0) 933 return (int64_t)~(~(uint64_t)l >> (r & 63)); 934 return (int64_t)((uint64_t)l >> (r & 63)); 935 case LT: 936 return l < r ? 1 : 0; 937 case LE: 938 return l <= r ? 1 : 0; 939 case GT: 940 return l > r ? 1 : 0; 941 case GE: 942 return l >= r ? 1 : 0; 943 case EQ: 944 return l == r ? 1 : 0; 945 case NE: 946 return l != r ? 1 : 0; 947 case BITAND: 948 return l & r; 949 case BITXOR: 950 return l ^ r; 951 case BITOR: 952 return l | r; 953 default: 954 lint_assert(/*CONSTCOND*/false); 955 /* NOTREACHED */ 956 } 957 } 958 959 static tnode_t * 960 fold_constant_integer(tnode_t *tn) 961 { 962 963 lint_assert(has_operands(tn)); 964 tspec_t t = tn->u.ops.left->tn_type->t_tspec; 965 int64_t l = tn->u.ops.left->u.value.u.integer; 966 int64_t r = is_binary(tn) ? tn->u.ops.right->u.value.u.integer : 0; 967 uint64_t mask = value_bits(size_in_bits(t)); 968 969 int64_t res; 970 bool overflow = false; 971 if (!is_integer(t) || is_uinteger(t)) { 972 uint64_t u_res = fold_unsigned_integer(tn->tn_op, 973 (uint64_t)l, (uint64_t)r, mask, &overflow); 974 if (u_res > mask) 975 overflow = true; 976 res = (int64_t)u_res; 977 if (overflow && hflag) { 978 char buf[128]; 979 if (is_binary(tn)) { 980 snprintf(buf, sizeof(buf), "%ju %s %ju", 981 (uintmax_t)l, op_name(tn->tn_op), 982 (uintmax_t)r); 983 } else { 984 snprintf(buf, sizeof(buf), "%s%ju", 985 op_name(tn->tn_op), (uintmax_t)l); 986 } 987 /* '%s' overflows '%s' */ 988 warning(141, buf, type_name(tn->tn_type)); 989 } 990 } else { 991 int64_t max_value = (int64_t)(mask >> 1); 992 int64_t min_value = -max_value - 1; 993 res = fold_signed_integer(tn->tn_op, 994 l, r, min_value, max_value, &overflow); 995 if (res < min_value || res > max_value) 996 overflow = true; 997 if (overflow && hflag) { 998 char buf[128]; 999 if (is_binary(tn)) { 1000 snprintf(buf, sizeof(buf), "%jd %s %jd", 1001 (intmax_t)l, op_name(tn->tn_op), 1002 (intmax_t)r); 1003 } else if (tn->tn_op == UMINUS && l < 0) { 1004 snprintf(buf, sizeof(buf), "-(%jd)", 1005 (intmax_t)l); 1006 } else { 1007 snprintf(buf, sizeof(buf), "%s%jd", 1008 op_name(tn->tn_op), (intmax_t)l); 1009 } 1010 /* '%s' overflows '%s' */ 1011 warning(141, buf, type_name(tn->tn_type)); 1012 } 1013 } 1014 1015 val_t *v = xcalloc(1, sizeof(*v)); 1016 v->v_tspec = tn->tn_type->t_tspec; 1017 v->u.integer = convert_integer(res, t, size_in_bits(t)); 1018 1019 tnode_t *cn = build_constant(tn->tn_type, v); 1020 if (tn->u.ops.left->tn_system_dependent) 1021 cn->tn_system_dependent = true; 1022 if (is_binary(tn) && tn->u.ops.right->tn_system_dependent) 1023 cn->tn_system_dependent = true; 1024 1025 return cn; 1026 } 1027 1028 static tnode_t * 1029 build_struct_access(op_t op, bool sys, tnode_t *ln, tnode_t *rn) 1030 { 1031 1032 lint_assert(rn->tn_op == NAME); 1033 lint_assert(is_member(rn->u.sym)); 1034 1035 bool lvalue = op == ARROW || ln->tn_lvalue; 1036 1037 if (op == POINT) 1038 ln = build_address(sys, ln, true); 1039 else if (ln->tn_type->t_tspec != PTR) { 1040 lint_assert(!allow_c90); 1041 lint_assert(is_integer(ln->tn_type->t_tspec)); 1042 ln = convert(NOOP, 0, expr_derive_type(gettyp(VOID), PTR), ln); 1043 } 1044 1045 tnode_t *ctn = build_integer_constant(PTRDIFF_TSPEC, 1046 rn->u.sym->u.s_member.sm_offset_in_bits / CHAR_SIZE); 1047 1048 type_t *ptr_tp = expr_derive_type(rn->tn_type, PTR); 1049 tnode_t *ntn = build_op(PLUS, sys, ptr_tp, ln, ctn); 1050 if (ln->tn_op == CON) 1051 ntn = fold_constant_integer(ntn); 1052 1053 op_t nop = rn->tn_type->t_bitfield ? FSEL : INDIR; 1054 ntn = build_op(nop, sys, ntn->tn_type->t_subt, ntn, NULL); 1055 if (!lvalue) 1056 ntn->tn_lvalue = false; 1057 1058 return ntn; 1059 } 1060 1061 /* 1062 * Get the size in bytes of type tp->t_subt, as a constant expression of type 1063 * ptrdiff_t as seen from the target platform. 1064 */ 1065 static tnode_t * 1066 subt_size_in_bytes(type_t *tp) 1067 { 1068 1069 lint_assert(tp->t_tspec == PTR); 1070 tp = tp->t_subt; 1071 1072 int elem = 1; 1073 while (tp->t_tspec == ARRAY) { 1074 elem *= tp->u.dimension; 1075 tp = tp->t_subt; 1076 } 1077 1078 int elsz_in_bits = 0; 1079 switch (tp->t_tspec) { 1080 case FUNC: 1081 /* pointer to function is not allowed here */ 1082 error(110); 1083 break; 1084 case VOID: 1085 /* cannot do pointer arithmetic on operand of unknown size */ 1086 gnuism(136); 1087 break; 1088 case STRUCT: 1089 case UNION: 1090 if ((elsz_in_bits = (int)tp->u.sou->sou_size_in_bits) == 0) 1091 /* cannot do pointer arithmetic on operand of ... */ 1092 error(136); 1093 break; 1094 case ENUM: 1095 if (is_incomplete(tp)) 1096 /* cannot do pointer arithmetic on operand of ... */ 1097 warning(136); 1098 /* FALLTHROUGH */ 1099 default: 1100 if ((elsz_in_bits = size_in_bits(tp->t_tspec)) == 0) 1101 /* cannot do pointer arithmetic on operand of ... */ 1102 error(136); 1103 else 1104 lint_assert(elsz_in_bits != -1); 1105 break; 1106 } 1107 1108 if (elem == 0 && elsz_in_bits != 0) 1109 /* cannot do pointer arithmetic on operand of unknown size */ 1110 error(136); 1111 1112 if (elsz_in_bits == 0) 1113 elsz_in_bits = CHAR_SIZE; 1114 1115 return build_integer_constant(PTRDIFF_TSPEC, 1116 (int64_t)(elem * elsz_in_bits / CHAR_SIZE)); 1117 } 1118 1119 static tnode_t * 1120 build_prepost_incdec(op_t op, bool sys, tnode_t *ln) 1121 { 1122 1123 lint_assert(ln != NULL); 1124 tnode_t *cn = ln->tn_type->t_tspec == PTR 1125 ? subt_size_in_bytes(ln->tn_type) 1126 : build_integer_constant(INT, 1); 1127 return build_op(op, sys, ln->tn_type, ln, cn); 1128 } 1129 1130 static void 1131 check_enum_array_index(const tnode_t *ln, const tnode_t *rn) 1132 { 1133 1134 if (ln->tn_op != ADDR || ln->u.ops.left->tn_op != NAME) 1135 return; 1136 1137 const type_t *ltp = ln->u.ops.left->tn_type; 1138 if (ltp->t_tspec != ARRAY || ltp->t_incomplete_array) 1139 return; 1140 1141 if (rn->tn_op != CVT || !rn->tn_type->t_is_enum) 1142 return; 1143 if (rn->u.ops.left->tn_op != LOAD) 1144 return; 1145 1146 const type_t *rtp = rn->u.ops.left->tn_type; 1147 const sym_t *ec = rtp->u.enumer->en_first_enumerator; 1148 const sym_t *max_ec = ec; 1149 lint_assert(ec != NULL); 1150 for (ec = ec->s_next; ec != NULL; ec = ec->s_next) 1151 if (ec->u.s_enum_constant > max_ec->u.s_enum_constant) 1152 max_ec = ec; 1153 1154 int64_t max_enum_value = max_ec->u.s_enum_constant; 1155 lint_assert(INT_MIN <= max_enum_value && max_enum_value <= INT_MAX); 1156 1157 int max_array_index = ltp->u.dimension - 1; 1158 if (max_enum_value == max_array_index) 1159 return; 1160 1161 if (max_enum_value == max_array_index + 1 && 1162 (strstr(max_ec->s_name, "MAX") != NULL || 1163 strstr(max_ec->s_name, "max") != NULL || 1164 strstr(max_ec->s_name, "NUM") != NULL || 1165 strstr(max_ec->s_name, "num") != NULL)) 1166 return; 1167 1168 /* maximum value %d of '%s' does not match maximum array index %d */ 1169 warning(348, (int)max_enum_value, type_name(rtp), max_array_index); 1170 print_previous_declaration(max_ec); 1171 } 1172 1173 static tnode_t * 1174 build_plus_minus(op_t op, bool sys, tnode_t *ln, tnode_t *rn) 1175 { 1176 1177 if (rn->tn_type->t_tspec == PTR && is_integer(ln->tn_type->t_tspec)) { 1178 tnode_t *tmp = ln; 1179 ln = rn; 1180 rn = tmp; 1181 /* pointer addition has integer on the left-hand side */ 1182 query_message(5); 1183 } 1184 1185 /* pointer +- integer */ 1186 tspec_t lt = ln->tn_type->t_tspec; 1187 tspec_t rt = rn->tn_type->t_tspec; 1188 if (lt == PTR && rt != PTR) { 1189 lint_assert(is_integer(rt)); 1190 1191 check_ctype_macro_invocation(ln, rn); 1192 check_enum_array_index(ln, rn); 1193 1194 tnode_t *elsz = subt_size_in_bytes(ln->tn_type); 1195 tspec_t szt = elsz->tn_type->t_tspec; 1196 if (rt != szt && rt != unsigned_type(szt)) 1197 rn = convert(NOOP, 0, elsz->tn_type, rn); 1198 1199 tnode_t *prod = build_op(MULT, sys, rn->tn_type, rn, elsz); 1200 if (rn->tn_op == CON) 1201 prod = fold_constant_integer(prod); 1202 1203 return build_op(op, sys, ln->tn_type, ln, prod); 1204 } 1205 1206 /* pointer - pointer */ 1207 if (rt == PTR) { 1208 lint_assert(lt == PTR); 1209 lint_assert(op == MINUS); 1210 1211 type_t *ptrdiff = gettyp(PTRDIFF_TSPEC); 1212 tnode_t *raw_diff = build_op(op, sys, ptrdiff, ln, rn); 1213 if (ln->tn_op == CON && rn->tn_op == CON) 1214 raw_diff = fold_constant_integer(raw_diff); 1215 1216 tnode_t *elsz = subt_size_in_bytes(ln->tn_type); 1217 balance(NOOP, &raw_diff, &elsz); 1218 1219 return build_op(DIV, sys, ptrdiff, raw_diff, elsz); 1220 } 1221 1222 return build_op(op, sys, ln->tn_type, ln, rn); 1223 } 1224 1225 static tnode_t * 1226 build_bit_shift(op_t op, bool sys, tnode_t *ln, tnode_t *rn) 1227 { 1228 1229 if (!allow_c90 && rn->tn_type->t_tspec != INT) 1230 // XXX: C1978 7.5 says: "Both [operators] perform the usual 1231 // arithmetic conversions on their operands." 1232 // TODO: Add a test to exercise this part of the code. 1233 rn = convert(NOOP, 0, gettyp(INT), rn); 1234 return build_op(op, sys, ln->tn_type, ln, rn); 1235 } 1236 1237 static bool 1238 is_null_pointer(const tnode_t *tn) 1239 { 1240 tspec_t t = tn->tn_type->t_tspec; 1241 1242 // TODO: Investigate how other pointers are stored, in particular, 1243 // whether a pointer constant can have a non-zero value. 1244 // If not, simplify the code below. 1245 return ((t == PTR && tn->tn_type->t_subt->t_tspec == VOID) 1246 || is_integer(t)) 1247 && (tn->tn_op == CON && tn->u.value.u.integer == 0); 1248 } 1249 1250 /* Return a type based on tp1, with added qualifiers from tp2. */ 1251 static type_t * 1252 merge_qualifiers(type_t *tp1, const type_t *tp2) 1253 { 1254 1255 lint_assert(tp1->t_tspec == PTR); 1256 lint_assert(tp2->t_tspec == PTR); 1257 1258 bool c1 = tp1->t_subt->t_const; 1259 bool c2 = tp2->t_subt->t_const; 1260 bool v1 = tp1->t_subt->t_volatile; 1261 bool v2 = tp2->t_subt->t_volatile; 1262 1263 if (c1 == (c1 | c2) && v1 == (v1 | v2)) 1264 return tp1; 1265 1266 type_t *nstp = expr_dup_type(tp1->t_subt); 1267 nstp->t_const |= c2; 1268 nstp->t_volatile |= v2; 1269 1270 type_t *ntp = expr_dup_type(tp1); 1271 ntp->t_subt = nstp; 1272 return ntp; 1273 } 1274 1275 /* See C99 6.5.15 "Conditional operator". */ 1276 static tnode_t * 1277 build_colon(bool sys, tnode_t *ln, tnode_t *rn) 1278 { 1279 tspec_t lt = ln->tn_type->t_tspec; 1280 tspec_t rt = rn->tn_type->t_tspec; 1281 1282 type_t *tp; 1283 if (is_arithmetic(lt) && is_arithmetic(rt)) 1284 /* The operands were already balanced in build_binary. */ 1285 tp = ln->tn_type; 1286 else if (lt == BOOL && rt == BOOL) 1287 tp = ln->tn_type; 1288 else if (lt == VOID || rt == VOID) 1289 tp = gettyp(VOID); 1290 else if (is_struct_or_union(lt)) { 1291 lint_assert(is_struct_or_union(rt)); 1292 lint_assert(ln->tn_type->u.sou == rn->tn_type->u.sou); 1293 if (is_incomplete(ln->tn_type)) { 1294 /* unknown operand size, op '%s' */ 1295 error(138, op_name(COLON)); 1296 return NULL; 1297 } 1298 tp = ln->tn_type; 1299 } else if (lt == PTR && is_integer(rt)) { 1300 if (rt != PTRDIFF_TSPEC) 1301 rn = convert(NOOP, 0, gettyp(PTRDIFF_TSPEC), rn); 1302 tp = ln->tn_type; 1303 } else if (rt == PTR && is_integer(lt)) { 1304 if (lt != PTRDIFF_TSPEC) 1305 ln = convert(NOOP, 0, gettyp(PTRDIFF_TSPEC), ln); 1306 tp = rn->tn_type; 1307 } else if (lt == PTR && is_null_pointer(rn)) 1308 tp = merge_qualifiers(ln->tn_type, rn->tn_type); 1309 else if (rt == PTR && is_null_pointer(ln)) 1310 tp = merge_qualifiers(rn->tn_type, ln->tn_type); 1311 else if (lt == PTR && ln->tn_type->t_subt->t_tspec == VOID) 1312 tp = merge_qualifiers(ln->tn_type, rn->tn_type); 1313 else if (rt == PTR && rn->tn_type->t_subt->t_tspec == VOID) 1314 tp = merge_qualifiers(rn->tn_type, ln->tn_type); 1315 else { 1316 /* 1317 * XXX For now we simply take the left type. This is probably 1318 * wrong, if one type contains a function prototype and the 1319 * other one, at the same place, only an old-style declaration. 1320 */ 1321 tp = merge_qualifiers(ln->tn_type, rn->tn_type); 1322 } 1323 1324 return build_op(COLON, sys, tp, ln, rn); 1325 } 1326 1327 /* TODO: check for varargs */ 1328 static bool 1329 is_cast_redundant(const tnode_t *tn) 1330 { 1331 const type_t *ntp = tn->tn_type, *otp = tn->u.ops.left->tn_type; 1332 tspec_t nt = ntp->t_tspec, ot = otp->t_tspec; 1333 1334 if (nt == BOOL || ot == BOOL) 1335 return nt == BOOL && ot == BOOL; 1336 1337 if (is_integer(nt) && is_integer(ot)) { 1338 unsigned int nw = width_in_bits(ntp), ow = width_in_bits(otp); 1339 if (is_uinteger(nt) == is_uinteger(ot)) 1340 return nw >= ow; 1341 return is_uinteger(ot) && nw > ow; 1342 } 1343 1344 if (is_complex(nt) || is_complex(ot)) 1345 return is_complex(nt) && is_complex(ot) && 1346 size_in_bits(nt) >= size_in_bits(ot); 1347 1348 if (is_floating(nt) && is_floating(ot)) 1349 return size_in_bits(nt) >= size_in_bits(ot); 1350 1351 if (nt == PTR && ot == PTR) { 1352 if (!ntp->t_subt->t_const && otp->t_subt->t_const) 1353 return false; 1354 if (!ntp->t_subt->t_volatile && otp->t_subt->t_volatile) 1355 return false; 1356 1357 if (ntp->t_subt->t_tspec == VOID || 1358 otp->t_subt->t_tspec == VOID || 1359 types_compatible(ntp->t_subt, otp->t_subt, 1360 false, false, NULL)) 1361 return true; 1362 } 1363 1364 return false; 1365 } 1366 1367 static bool 1368 is_assignment(op_t op) 1369 { 1370 1371 return op == ASSIGN || 1372 op == MULASS || 1373 op == DIVASS || 1374 op == MODASS || 1375 op == ADDASS || 1376 op == SUBASS || 1377 op == SHLASS || 1378 op == SHRASS || 1379 op == ANDASS || 1380 op == XORASS || 1381 op == ORASS || 1382 op == RETURN || 1383 op == INIT; 1384 } 1385 1386 static tnode_t * 1387 build_assignment(op_t op, bool sys, tnode_t *ln, tnode_t *rn) 1388 { 1389 1390 tspec_t lt = ln->tn_type->t_tspec; 1391 tspec_t rt = rn->tn_type->t_tspec; 1392 1393 if (any_query_enabled && is_assignment(rn->tn_op)) { 1394 /* chained assignment with '%s' and '%s' */ 1395 query_message(10, op_name(op), op_name(rn->tn_op)); 1396 } 1397 1398 if ((op == ADDASS || op == SUBASS) && lt == PTR) { 1399 lint_assert(is_integer(rt)); 1400 tnode_t *ctn = subt_size_in_bytes(ln->tn_type); 1401 if (rn->tn_type->t_tspec != ctn->tn_type->t_tspec) 1402 rn = convert(NOOP, 0, ctn->tn_type, rn); 1403 rn = build_op(MULT, sys, rn->tn_type, rn, ctn); 1404 if (rn->u.ops.left->tn_op == CON) 1405 rn = fold_constant_integer(rn); 1406 } 1407 1408 if ((op == ASSIGN || op == RETURN || op == INIT) && 1409 (lt == STRUCT || rt == STRUCT)) { 1410 lint_assert(lt == rt); 1411 lint_assert(ln->tn_type->u.sou == rn->tn_type->u.sou); 1412 if (is_incomplete(ln->tn_type)) { 1413 if (op == RETURN) 1414 /* cannot return incomplete type */ 1415 error(212); 1416 else 1417 /* unknown operand size, op '%s' */ 1418 error(138, op_name(op)); 1419 return NULL; 1420 } 1421 } 1422 1423 if (op == SHLASS && hflag && allow_trad && allow_c90 1424 && portable_rank_cmp(lt, rt) < 0) 1425 /* semantics of '%s' change in C90; ... */ 1426 warning(118, "<<="); 1427 1428 if (op != SHLASS && op != SHRASS 1429 && (op == ASSIGN || lt != PTR) 1430 && (lt != rt || (ln->tn_type->t_bitfield && rn->tn_op == CON))) { 1431 rn = convert(op, 0, ln->tn_type, rn); 1432 rt = lt; 1433 } 1434 1435 if (any_query_enabled && rn->tn_op == CVT && rn->tn_cast && 1436 types_compatible(ln->tn_type, rn->tn_type, false, false, NULL) && 1437 is_cast_redundant(rn)) { 1438 /* redundant cast from '%s' to '%s' before assignment */ 1439 query_message(7, type_name(rn->u.ops.left->tn_type), 1440 type_name(rn->tn_type)); 1441 } 1442 1443 return build_op(op, sys, ln->tn_type, ln, rn); 1444 } 1445 1446 static tnode_t * 1447 build_real_imag(op_t op, bool sys, tnode_t *ln) 1448 { 1449 1450 lint_assert(ln != NULL); 1451 if (ln->tn_op == NAME) { 1452 /* 1453 * This may be too much, but it avoids wrong warnings. See 1454 * d_c99_complex_split.c. 1455 */ 1456 mark_as_used(ln->u.sym, false, false); 1457 mark_as_set(ln->u.sym); 1458 } 1459 1460 tspec_t t; 1461 switch (ln->tn_type->t_tspec) { 1462 case LCOMPLEX: 1463 t = LDOUBLE; 1464 break; 1465 case DCOMPLEX: 1466 t = DOUBLE; 1467 break; 1468 case FCOMPLEX: 1469 t = FLOAT; 1470 break; 1471 default: 1472 /* '__%s__' is illegal for type '%s' */ 1473 error(276, op == REAL ? "real" : "imag", 1474 type_name(ln->tn_type)); 1475 return NULL; 1476 } 1477 1478 tnode_t *ntn = build_op(op, sys, gettyp(t), ln, NULL); 1479 ntn->tn_lvalue = true; 1480 return ntn; 1481 } 1482 1483 static bool 1484 is_confusing_precedence(op_t op, op_t lop, bool lparen, op_t rop, bool rparen) 1485 { 1486 1487 if (op == SHL || op == SHR) { 1488 if (!lparen && (lop == PLUS || lop == MINUS)) 1489 return true; 1490 if (!rparen && (rop == PLUS || rop == MINUS)) 1491 return true; 1492 return false; 1493 } 1494 1495 if (op == LOGOR) { 1496 if (!lparen && lop == LOGAND) 1497 return true; 1498 if (!rparen && rop == LOGAND) 1499 return true; 1500 return false; 1501 } 1502 1503 lint_assert(op == BITAND || op == BITXOR || op == BITOR); 1504 if (!lparen && lop != op) { 1505 if (lop == PLUS || lop == MINUS) 1506 return true; 1507 if (lop == BITAND || lop == BITXOR) 1508 return true; 1509 } 1510 if (!rparen && rop != op) { 1511 if (rop == PLUS || rop == MINUS) 1512 return true; 1513 if (rop == BITAND || rop == BITXOR) 1514 return true; 1515 } 1516 return false; 1517 } 1518 1519 /* 1520 * Print a warning if the given node has operands which should be 1521 * parenthesized. 1522 * 1523 * XXX Does not work if an operand is a constant expression. Constant 1524 * expressions are already folded. 1525 */ 1526 static void 1527 check_precedence_confusion(tnode_t *tn) 1528 { 1529 tnode_t *ln, *rn; 1530 1531 if (!hflag) 1532 return; 1533 1534 debug_node(tn); 1535 1536 lint_assert(is_binary(tn)); 1537 for (ln = tn->u.ops.left; ln->tn_op == CVT; ln = ln->u.ops.left) 1538 continue; 1539 for (rn = tn->u.ops.right; rn->tn_op == CVT; rn = rn->u.ops.left) 1540 continue; 1541 1542 if (is_confusing_precedence(tn->tn_op, 1543 ln->tn_op, ln->tn_parenthesized, 1544 rn->tn_op, rn->tn_parenthesized)) { 1545 /* precedence confusion possible: parenthesize! */ 1546 warning(169); 1547 } 1548 } 1549 1550 static tnode_t * 1551 fold_constant_compare_zero(tnode_t *tn) 1552 { 1553 1554 val_t *v = xcalloc(1, sizeof(*v)); 1555 v->v_tspec = tn->tn_type->t_tspec; 1556 lint_assert(v->v_tspec == INT || (Tflag && v->v_tspec == BOOL)); 1557 1558 lint_assert(has_operands(tn)); 1559 bool l = constant_is_nonzero(tn->u.ops.left); 1560 bool r = is_binary(tn) && constant_is_nonzero(tn->u.ops.right); 1561 1562 switch (tn->tn_op) { 1563 case NOT: 1564 if (hflag && !suppress_constcond) 1565 /* constant operand to '!' */ 1566 warning(239); 1567 v->u.integer = !l ? 1 : 0; 1568 break; 1569 case LOGAND: 1570 v->u.integer = l && r ? 1 : 0; 1571 break; 1572 case LOGOR: 1573 v->u.integer = l || r ? 1 : 0; 1574 break; 1575 default: 1576 lint_assert(/*CONSTCOND*/false); 1577 } 1578 1579 return build_constant(tn->tn_type, v); 1580 } 1581 1582 static long double 1583 floating_error_value(tspec_t t, long double lv) 1584 { 1585 if (t == FLOAT) 1586 return lv < 0 ? -FLT_MAX : FLT_MAX; 1587 if (t == DOUBLE) 1588 return lv < 0 ? -DBL_MAX : DBL_MAX; 1589 /* 1590 * When NetBSD is cross-built in MKLINT=yes mode on x86_64 for sparc64, 1591 * tools/lint checks this code while building usr.bin/xlint. In that 1592 * situation, lint uses the preprocessor for sparc64, in which the type 1593 * 'long double' is IEEE-754-binary128, affecting the macro LDBL_MAX 1594 * below. The type 'long double', as well as the strtold 1595 * implementation, comes from the host platform x86_64 though, where 1596 * 'long double' consumes 128 bits as well but only uses 80 of them. 1597 * The exponent range of the two 'long double' types is the same, but 1598 * the maximum finite value differs due to the extended precision on 1599 * sparc64. 1600 * 1601 * To properly handle the data types of the target platform, lint would 1602 * have to implement the floating-point types in a platform-independent 1603 * way, which is not worth the effort, given how few programs 1604 * practically use 'long double'. 1605 */ 1606 /* LINTED 248: floating-point constant out of range */ 1607 long double max = LDBL_MAX; 1608 return lv < 0 ? -max : max; 1609 } 1610 1611 static bool 1612 is_floating_overflow(tspec_t t, long double val) 1613 { 1614 if (fpe != 0 || isfinite(val) == 0) 1615 return true; 1616 if (t == FLOAT && (val > FLT_MAX || val < -FLT_MAX)) 1617 return true; 1618 if (t == DOUBLE && (val > DBL_MAX || val < -DBL_MAX)) 1619 return true; 1620 return false; 1621 } 1622 1623 static tnode_t * 1624 fold_constant_floating(tnode_t *tn) 1625 { 1626 1627 fpe = 0; 1628 1629 tspec_t t = tn->tn_type->t_tspec; 1630 1631 val_t *v = xcalloc(1, sizeof(*v)); 1632 v->v_tspec = t; 1633 1634 lint_assert(is_floating(t)); 1635 lint_assert(has_operands(tn)); 1636 lint_assert(t == tn->u.ops.left->tn_type->t_tspec); 1637 lint_assert(!is_binary(tn) || t == tn->u.ops.right->tn_type->t_tspec); 1638 1639 long double lv = tn->u.ops.left->u.value.u.floating; 1640 long double rv = is_binary(tn) ? tn->u.ops.right->u.value.u.floating 1641 : 0.0; 1642 1643 switch (tn->tn_op) { 1644 case UPLUS: 1645 v->u.floating = lv; 1646 break; 1647 case UMINUS: 1648 v->u.floating = -lv; 1649 break; 1650 case MULT: 1651 v->u.floating = lv * rv; 1652 break; 1653 case DIV: 1654 if (rv == 0.0) { 1655 /* division by 0 */ 1656 error(139); 1657 v->u.floating = floating_error_value(t, lv); 1658 } else { 1659 v->u.floating = lv / rv; 1660 } 1661 break; 1662 case PLUS: 1663 v->u.floating = lv + rv; 1664 break; 1665 case MINUS: 1666 v->u.floating = lv - rv; 1667 break; 1668 case LT: 1669 v->u.integer = lv < rv ? 1 : 0; 1670 break; 1671 case LE: 1672 v->u.integer = lv <= rv ? 1 : 0; 1673 break; 1674 case GE: 1675 v->u.integer = lv >= rv ? 1 : 0; 1676 break; 1677 case GT: 1678 v->u.integer = lv > rv ? 1 : 0; 1679 break; 1680 case EQ: 1681 v->u.integer = lv == rv ? 1 : 0; 1682 break; 1683 case NE: 1684 v->u.integer = lv != rv ? 1 : 0; 1685 break; 1686 default: 1687 lint_assert(/*CONSTCOND*/false); 1688 } 1689 1690 // XXX: Must not access u.floating after setting u.integer. 1691 lint_assert(fpe != 0 || isnan(v->u.floating) == 0); 1692 if (is_complex(v->v_tspec)) { 1693 /* 1694 * Don't warn, as lint doesn't model the imaginary part of 1695 * complex numbers. 1696 */ 1697 fpe = 0; 1698 } else if (is_floating_overflow(t, v->u.floating)) { 1699 /* operator '%s' produces floating point overflow */ 1700 warning(142, op_name(tn->tn_op)); 1701 v->u.floating = floating_error_value(t, v->u.floating); 1702 fpe = 0; 1703 } 1704 1705 return build_constant(tn->tn_type, v); 1706 } 1707 1708 static void 1709 use(const tnode_t *tn) 1710 { 1711 if (tn == NULL) 1712 return; 1713 switch (tn->tn_op) { 1714 case NAME: 1715 mark_as_used(tn->u.sym, false /* XXX */, false /* XXX */); 1716 break; 1717 case CON: 1718 case STRING: 1719 break; 1720 case CALL:; 1721 const function_call *call = tn->u.call; 1722 for (size_t i = 0, n = call->args_len; i < n; i++) 1723 use(call->args[i]); 1724 break; 1725 default: 1726 lint_assert(has_operands(tn)); 1727 use(tn->u.ops.left); 1728 if (is_binary(tn)) 1729 use(tn->u.ops.right); 1730 } 1731 } 1732 1733 /* 1734 * Create a tree node for a binary operator and its two operands. Also called 1735 * for unary operators; in that case rn is NULL. 1736 * 1737 * Function calls, sizeof and casts are handled elsewhere. 1738 */ 1739 tnode_t * 1740 build_binary(tnode_t *ln, op_t op, bool sys, tnode_t *rn) 1741 { 1742 const mod_t *mp = &modtab[op]; 1743 1744 /* If there was an error in one of the operands, return. */ 1745 if (ln == NULL || (mp->m_binary && rn == NULL)) 1746 return NULL; 1747 1748 if (mp->m_value_context || mp->m_compares_with_zero) 1749 ln = cconv(ln); 1750 if (mp->m_binary && op != ARROW && op != POINT) 1751 rn = cconv(rn); 1752 1753 if (mp->m_comparison) 1754 check_integer_comparison(op, ln, rn); 1755 1756 if (mp->m_value_context || mp->m_compares_with_zero) 1757 ln = promote(op, false, ln); 1758 if (mp->m_binary && op != ARROW && op != POINT && 1759 op != ASSIGN && op != RETURN && op != INIT) 1760 rn = promote(op, false, rn); 1761 1762 if (mp->m_warn_if_left_unsigned_in_c90 && 1763 ln->tn_op == CON && ln->u.value.v_unsigned_since_c90) { 1764 /* C90 treats constant as unsigned, op '%s' */ 1765 warning(218, op_name(op)); 1766 ln->u.value.v_unsigned_since_c90 = false; 1767 } 1768 if (mp->m_warn_if_right_unsigned_in_c90 && 1769 rn->tn_op == CON && rn->u.value.v_unsigned_since_c90) { 1770 /* C90 treats constant as unsigned, op '%s' */ 1771 warning(218, op_name(op)); 1772 rn->u.value.v_unsigned_since_c90 = false; 1773 } 1774 1775 if (mp->m_balance_operands || (!allow_c90 && (op == SHL || op == SHR))) 1776 balance(op, &ln, &rn); 1777 1778 if (!typeok(op, 0, ln, rn)) 1779 return NULL; 1780 1781 tnode_t *ntn; 1782 switch (op) { 1783 case POINT: 1784 case ARROW: 1785 ntn = build_struct_access(op, sys, ln, rn); 1786 break; 1787 case INCAFT: 1788 case DECAFT: 1789 case INCBEF: 1790 case DECBEF: 1791 ntn = build_prepost_incdec(op, sys, ln); 1792 break; 1793 case ADDR: 1794 ntn = build_address(sys, ln, false); 1795 break; 1796 case INDIR: 1797 ntn = build_op(INDIR, sys, ln->tn_type->t_subt, ln, NULL); 1798 break; 1799 case PLUS: 1800 case MINUS: 1801 ntn = build_plus_minus(op, sys, ln, rn); 1802 break; 1803 case SHL: 1804 case SHR: 1805 ntn = build_bit_shift(op, sys, ln, rn); 1806 break; 1807 case COLON: 1808 ntn = build_colon(sys, ln, rn); 1809 break; 1810 case ASSIGN: 1811 case MULASS: 1812 case DIVASS: 1813 case MODASS: 1814 case ADDASS: 1815 case SUBASS: 1816 case SHLASS: 1817 case SHRASS: 1818 case ANDASS: 1819 case XORASS: 1820 case ORASS: 1821 case RETURN: 1822 case INIT: 1823 ntn = build_assignment(op, sys, ln, rn); 1824 break; 1825 case COMMA: 1826 if (any_query_enabled) { 1827 /* comma operator with types '%s' and '%s' */ 1828 query_message(12, 1829 type_name(ln->tn_type), type_name(rn->tn_type)); 1830 } 1831 /* FALLTHROUGH */ 1832 case QUEST: 1833 ntn = build_op(op, sys, rn->tn_type, ln, rn); 1834 break; 1835 case REAL: 1836 case IMAG: 1837 ntn = build_real_imag(op, sys, ln); 1838 break; 1839 default: 1840 lint_assert(mp->m_binary == (rn != NULL)); 1841 type_t *rettp = mp->m_returns_bool 1842 ? gettyp(Tflag ? BOOL : INT) : ln->tn_type; 1843 ntn = build_op(op, sys, rettp, ln, rn); 1844 break; 1845 } 1846 1847 if (ntn == NULL) 1848 return NULL; 1849 1850 if (mp->m_possible_precedence_confusion) 1851 check_precedence_confusion(ntn); 1852 1853 if (hflag && !suppress_constcond && 1854 mp->m_compares_with_zero && 1855 (ln->tn_op == CON || 1856 (mp->m_binary && op != QUEST && rn->tn_op == CON)) && 1857 /* XXX: rn->tn_system_dependent should be checked as well */ 1858 !ln->tn_system_dependent) 1859 /* constant in conditional context */ 1860 warning(161); 1861 1862 if (mp->m_fold_constant_operands && ln->tn_op == CON) { 1863 if (!mp->m_binary || rn->tn_op == CON) { 1864 if (mp->m_compares_with_zero) 1865 ntn = fold_constant_compare_zero(ntn); 1866 else if (is_floating(ntn->tn_type->t_tspec)) 1867 ntn = fold_constant_floating(ntn); 1868 else 1869 ntn = fold_constant_integer(ntn); 1870 } else if (op == QUEST) { 1871 lint_assert(has_operands(rn)); 1872 use(ln->u.value.u.integer != 0 1873 ? rn->u.ops.right : rn->u.ops.left); 1874 ntn = ln->u.value.u.integer != 0 1875 ? rn->u.ops.left : rn->u.ops.right; 1876 } 1877 } 1878 1879 return ntn; 1880 } 1881 1882 tnode_t * 1883 build_unary(op_t op, bool sys, tnode_t *tn) 1884 { 1885 return build_binary(tn, op, sys, NULL); 1886 } 1887 1888 static bool 1889 are_members_compatible(const sym_t *a, const sym_t *b) 1890 { 1891 if (a->u.s_member.sm_offset_in_bits != b->u.s_member.sm_offset_in_bits) 1892 return false; 1893 1894 const type_t *atp = a->s_type; 1895 const type_t *btp = b->s_type; 1896 bool w = false; 1897 if (!types_compatible(atp, btp, false, false, &w) && !w) 1898 return false; 1899 if (a->s_bitfield != b->s_bitfield) 1900 return false; 1901 if (a->s_bitfield) { 1902 if (atp->t_bit_field_width != btp->t_bit_field_width) 1903 return false; 1904 if (atp->t_bit_field_offset != btp->t_bit_field_offset) 1905 return false; 1906 } 1907 return true; 1908 } 1909 1910 /* 1911 * Return whether all struct/union members with the same name have the same 1912 * type and offset. 1913 */ 1914 static bool 1915 all_members_compatible(const sym_t *msym) 1916 { 1917 for (const sym_t *csym = msym; 1918 csym != NULL; csym = csym->s_symtab_next) { 1919 if (!is_member(csym)) 1920 continue; 1921 if (strcmp(msym->s_name, csym->s_name) != 0) 1922 continue; 1923 1924 for (const sym_t *sym = csym->s_symtab_next; 1925 sym != NULL; sym = sym->s_symtab_next) { 1926 if (is_member(sym) 1927 && strcmp(csym->s_name, sym->s_name) == 0 1928 && !are_members_compatible(csym, sym)) 1929 return false; 1930 } 1931 } 1932 return true; 1933 } 1934 1935 sym_t * 1936 find_member(const struct_or_union *sou, const char *name) 1937 { 1938 for (sym_t *mem = sou->sou_first_member; 1939 mem != NULL; mem = mem->s_next) { 1940 lint_assert(is_member(mem)); 1941 lint_assert(mem->u.s_member.sm_containing_type == sou); 1942 if (strcmp(mem->s_name, name) == 0) 1943 return mem; 1944 } 1945 1946 for (sym_t *mem = sou->sou_first_member; 1947 mem != NULL; mem = mem->s_next) { 1948 if (is_struct_or_union(mem->s_type->t_tspec) 1949 && mem->s_name == unnamed) { 1950 sym_t *nested_mem = 1951 find_member(mem->s_type->u.sou, name); 1952 if (nested_mem != NULL) 1953 return nested_mem; 1954 } 1955 } 1956 return NULL; 1957 } 1958 1959 /* 1960 * Remove the member if it was unknown until now, which means 1961 * that no defined struct or union has a member with the same name. 1962 */ 1963 static void 1964 remove_unknown_member(tnode_t *tn, sym_t *msym) 1965 { 1966 /* type '%s' does not have member '%s' */ 1967 error(101, type_name(tn->tn_type), msym->s_name); 1968 symtab_remove_forever(msym); 1969 msym->s_kind = SK_MEMBER; 1970 msym->s_scl = STRUCT_MEMBER; 1971 1972 struct_or_union *sou = expr_zero_alloc(sizeof(*sou), 1973 "struct_or_union"); 1974 sou->sou_tag = expr_zero_alloc(sizeof(*sou->sou_tag), "sym"); 1975 sou->sou_tag->s_name = unnamed; 1976 1977 msym->u.s_member.sm_containing_type = sou; 1978 /* 1979 * The member sm_offset_in_bits is not needed here since this symbol 1980 * can only be used for error reporting. 1981 */ 1982 } 1983 1984 /* 1985 * Returns a symbol which has the same name as 'msym' and is a member of the 1986 * struct or union specified by 'tn'. 1987 */ 1988 static sym_t * 1989 struct_or_union_member(tnode_t *tn, op_t op, sym_t *msym) 1990 { 1991 1992 /* Determine the tag type of which msym is expected to be a member. */ 1993 const type_t *tp = NULL; 1994 if (op == POINT && is_struct_or_union(tn->tn_type->t_tspec)) 1995 tp = tn->tn_type; 1996 if (op == ARROW && tn->tn_type->t_tspec == PTR 1997 && is_struct_or_union(tn->tn_type->t_subt->t_tspec)) 1998 tp = tn->tn_type->t_subt; 1999 struct_or_union *sou = tp != NULL ? tp->u.sou : NULL; 2000 2001 if (sou != NULL) { 2002 sym_t *nested_mem = find_member(sou, msym->s_name); 2003 if (nested_mem != NULL) 2004 return nested_mem; 2005 } 2006 2007 if (msym->s_scl == NO_SCL) { 2008 remove_unknown_member(tn, msym); 2009 return msym; 2010 } 2011 2012 bool eq = all_members_compatible(msym); 2013 2014 /* 2015 * Now handle the case in which the left operand refers really to a 2016 * struct/union, but the right operand is not member of it. 2017 */ 2018 if (sou != NULL) { 2019 if (eq && !allow_c90) 2020 /* illegal use of member '%s' */ 2021 warning(102, msym->s_name); 2022 else 2023 /* illegal use of member '%s' */ 2024 error(102, msym->s_name); 2025 return msym; 2026 } 2027 2028 if (eq) { 2029 if (op == POINT) { 2030 if (!allow_c90) 2031 /* left operand of '.' must be struct ... */ 2032 warning(103, type_name(tn->tn_type)); 2033 else 2034 /* left operand of '.' must be struct ... */ 2035 error(103, type_name(tn->tn_type)); 2036 } else { 2037 if (!allow_c90 && tn->tn_type->t_tspec == PTR) 2038 /* left operand of '->' must be pointer ... */ 2039 warning(104, type_name(tn->tn_type)); 2040 else 2041 /* left operand of '->' must be pointer ... */ 2042 error(104, type_name(tn->tn_type)); 2043 } 2044 } else { 2045 if (!allow_c90) 2046 /* non-unique member requires struct/union %s */ 2047 error(105, op == POINT ? "object" : "pointer"); 2048 else 2049 /* unacceptable operand of '%s' */ 2050 error(111, op_name(op)); 2051 } 2052 2053 return msym; 2054 } 2055 2056 tnode_t * 2057 build_member_access(tnode_t *ln, op_t op, bool sys, sbuf_t *member) 2058 { 2059 sym_t *msym; 2060 2061 if (ln == NULL) 2062 return NULL; 2063 2064 if (op == ARROW) 2065 /* must do this before struct_or_union_member is called */ 2066 ln = cconv(ln); 2067 msym = struct_or_union_member(ln, op, getsym(member)); 2068 return build_binary(ln, op, sys, build_name(msym, false)); 2069 } 2070 2071 /* 2072 * Perform class conversions. 2073 * 2074 * Arrays of type T are converted into pointers to type T. 2075 * Functions are converted to pointers to functions. 2076 * Lvalues are converted to rvalues. 2077 * 2078 * C99 6.3 "Conversions" 2079 * C99 6.3.2 "Other operands" 2080 * C99 6.3.2.1 "Lvalues, arrays, and function designators" 2081 */ 2082 tnode_t * 2083 cconv(tnode_t *tn) 2084 { 2085 if (tn->tn_type->t_tspec == ARRAY) { 2086 if (!tn->tn_lvalue) { 2087 /* XXX print correct operator */ 2088 /* %soperand of '%s' must be lvalue */ 2089 gnuism(114, "", op_name(ADDR)); 2090 } 2091 tn = build_op(ADDR, tn->tn_sys, 2092 expr_derive_type(tn->tn_type->t_subt, PTR), tn, NULL); 2093 } 2094 2095 if (tn->tn_type->t_tspec == FUNC) 2096 tn = build_address(tn->tn_sys, tn, true); 2097 2098 if (tn->tn_lvalue) { 2099 type_t *tp = expr_dup_type(tn->tn_type); 2100 /* C99 6.3.2.1p2 sentence 2 says to remove the qualifiers. */ 2101 tp->t_const = tp->t_volatile = false; 2102 tn = build_op(LOAD, tn->tn_sys, tp, tn, NULL); 2103 } 2104 2105 return tn; 2106 } 2107 2108 const tnode_t * 2109 before_conversion(const tnode_t *tn) 2110 { 2111 while (tn->tn_op == CVT && !tn->tn_cast) 2112 tn = tn->u.ops.left; 2113 return tn; 2114 } 2115 2116 /* 2117 * Most errors required by C90 are reported in struct_or_union_member(). 2118 * Here we only check for totally wrong things. 2119 */ 2120 static bool 2121 typeok_point(const tnode_t *ln, const type_t *ltp, tspec_t lt) 2122 { 2123 if (is_struct_or_union(lt)) 2124 return true; 2125 2126 if (lt == FUNC || lt == VOID || ltp->t_bitfield) 2127 goto wrong; 2128 2129 /* 2130 * Some C dialects from before C90 tolerated any lvalue on the 2131 * left-hand side of the '.' operator, allowing things like 'char 2132 * st[100]; st.st_mtime', assuming that the member 'st_mtime' only 2133 * occurred in a single struct; see typeok_arrow. 2134 */ 2135 if (ln->tn_lvalue) 2136 return true; 2137 2138 wrong: 2139 /* With allow_c90 we already got an error */ 2140 if (!allow_c90) 2141 /* unacceptable operand of '%s' */ 2142 error(111, op_name(POINT)); 2143 2144 return false; 2145 } 2146 2147 static bool 2148 typeok_arrow(tspec_t lt) 2149 { 2150 /* 2151 * C1978 Appendix A 14.1 says: <quote>In fact, any lvalue is allowed 2152 * before '.', and that lvalue is then assumed to have the form of the 2153 * structure of which the name of the right is a member. [...] Such 2154 * constructions are non-portable.</quote> 2155 */ 2156 if (lt == PTR || (!allow_c90 && is_integer(lt))) 2157 return true; 2158 2159 /* With allow_c90 we already got an error */ 2160 if (!allow_c90) 2161 /* unacceptable operand of '%s' */ 2162 error(111, op_name(ARROW)); 2163 return false; 2164 } 2165 2166 static bool 2167 typeok_incdec(op_t op, const tnode_t *tn, const type_t *tp) 2168 { 2169 /* operand has scalar type (checked in typeok) */ 2170 if (!tn->tn_lvalue) { 2171 if (tn->tn_op == CVT && tn->tn_cast && 2172 tn->u.ops.left->tn_op == LOAD) 2173 /* a cast does not yield an lvalue */ 2174 error(163); 2175 /* %soperand of '%s' must be lvalue */ 2176 error(114, "", op_name(op)); 2177 return false; 2178 } 2179 if (tp->t_const && allow_c90) 2180 /* %soperand of '%s' must be modifiable lvalue */ 2181 warning(115, "", op_name(op)); 2182 return true; 2183 } 2184 2185 static bool 2186 typeok_address(op_t op, const tnode_t *tn, const type_t *tp, tspec_t t) 2187 { 2188 if (t == ARRAY || t == FUNC) { 2189 /* ok, a warning comes later (in build_address()) */ 2190 } else if (!tn->tn_lvalue) { 2191 if (tn->tn_op == CVT && tn->tn_cast && 2192 tn->u.ops.left->tn_op == LOAD) 2193 /* a cast does not yield an lvalue */ 2194 error(163); 2195 /* %soperand of '%s' must be lvalue */ 2196 error(114, "", op_name(op)); 2197 return false; 2198 } else if (is_scalar(t)) { 2199 if (tp->t_bitfield) { 2200 /* cannot take address of bit-field */ 2201 error(112); 2202 return false; 2203 } 2204 } else if (t != STRUCT && t != UNION) { 2205 /* unacceptable operand of '%s' */ 2206 error(111, op_name(op)); 2207 return false; 2208 } 2209 if (tn->tn_op == NAME && tn->u.sym->s_register) { 2210 /* cannot take address of register '%s' */ 2211 error(113, tn->u.sym->s_name); 2212 return false; 2213 } 2214 return true; 2215 } 2216 2217 static bool 2218 typeok_indir(const type_t *tp, tspec_t t) 2219 { 2220 2221 if (t != PTR) { 2222 /* cannot dereference non-pointer type '%s' */ 2223 error(96, type_name(tp)); 2224 return false; 2225 } 2226 return true; 2227 } 2228 2229 static void 2230 warn_incompatible_types(op_t op, 2231 const type_t *ltp, tspec_t lt, 2232 const type_t *rtp, tspec_t rt) 2233 { 2234 bool binary = modtab[op].m_binary; 2235 2236 if (lt == VOID || (binary && rt == VOID)) { 2237 /* void type illegal in expression */ 2238 error(109); 2239 } else if (op == ASSIGN) 2240 /* cannot assign to '%s' from '%s' */ 2241 error(171, type_name(ltp), type_name(rtp)); 2242 else if (binary) 2243 /* operands of '%s' have incompatible types '%s' and '%s' */ 2244 error(107, op_name(op), type_name(ltp), type_name(rtp)); 2245 else { 2246 lint_assert(rt == NO_TSPEC); 2247 /* operand of '%s' has invalid type '%s' */ 2248 error(108, op_name(op), type_name(ltp)); 2249 } 2250 } 2251 2252 static bool 2253 typeok_plus(op_t op, 2254 const type_t *ltp, tspec_t lt, 2255 const type_t *rtp, tspec_t rt) 2256 { 2257 /* operands have scalar types (checked in typeok) */ 2258 if ((lt == PTR && !is_integer(rt)) || (rt == PTR && !is_integer(lt))) { 2259 warn_incompatible_types(op, ltp, lt, rtp, rt); 2260 return false; 2261 } 2262 return true; 2263 } 2264 2265 static bool 2266 typeok_minus(op_t op, 2267 const type_t *ltp, tspec_t lt, 2268 const type_t *rtp, tspec_t rt) 2269 { 2270 /* operands have scalar types (checked in typeok) */ 2271 if ((lt == PTR && rt != PTR && !is_integer(rt)) || 2272 (lt != PTR && rt == PTR)) { 2273 warn_incompatible_types(op, ltp, lt, rtp, rt); 2274 return false; 2275 } 2276 if (lt == PTR && rt == PTR && 2277 !types_compatible(ltp->t_subt, rtp->t_subt, true, false, NULL)) { 2278 /* illegal pointer subtraction */ 2279 error(116); 2280 } 2281 return true; 2282 } 2283 2284 static void 2285 typeok_shr(op_t op, 2286 const tnode_t *ln, tspec_t lt, 2287 const tnode_t *rn, tspec_t rt) 2288 { 2289 tspec_t olt = before_conversion(ln)->tn_type->t_tspec; 2290 tspec_t ort = before_conversion(rn)->tn_type->t_tspec; 2291 2292 /* operands have integer types (checked in typeok) */ 2293 if (pflag && !is_uinteger(olt)) { 2294 integer_constraints lc = ic_expr(ln); 2295 if (!ic_maybe_signed(ln->tn_type, &lc)) 2296 return; 2297 2298 if (ln->tn_op != CON) 2299 /* bitwise '%s' on signed value possibly nonportable */ 2300 warning(117, op_name(op)); 2301 else if (ln->u.value.u.integer < 0) 2302 /* bitwise '%s' on signed value nonportable */ 2303 warning(120, op_name(op)); 2304 } else if (allow_trad && allow_c90 && 2305 !is_uinteger(olt) && is_uinteger(ort)) { 2306 /* The left operand would become unsigned in traditional C. */ 2307 if (hflag && (ln->tn_op != CON || ln->u.value.u.integer < 0)) { 2308 /* semantics of '%s' change in C90; use ... */ 2309 warning(118, op_name(op)); 2310 } 2311 } else if (allow_trad && allow_c90 && 2312 !is_uinteger(olt) && !is_uinteger(ort) && 2313 portable_rank_cmp(lt, rt) < 0) { 2314 /* 2315 * In traditional C, the left operand would be extended 2316 * (possibly sign-extended) and then shifted. 2317 */ 2318 if (hflag && (ln->tn_op != CON || ln->u.value.u.integer < 0)) { 2319 /* semantics of '%s' change in C90; use ... */ 2320 warning(118, op_name(op)); 2321 } 2322 } 2323 } 2324 2325 static void 2326 typeok_shl(op_t op, tspec_t lt, tspec_t rt) 2327 { 2328 /* 2329 * C90 does not perform balancing for shift operations, but traditional 2330 * C does. If the width of the right operand is greater than the width 2331 * of the left operand, then in traditional C the left operand would be 2332 * extended to the width of the right operand. For SHL this may result 2333 * in different results. 2334 */ 2335 if (portable_rank_cmp(lt, rt) < 0) { 2336 /* 2337 * XXX If both operands are constant, make sure that there is 2338 * really a difference between C90 and traditional C. 2339 */ 2340 if (hflag && allow_trad && allow_c90) 2341 /* semantics of '%s' change in C90; use ... */ 2342 warning(118, op_name(op)); 2343 } 2344 } 2345 2346 static void 2347 typeok_shift(const type_t *ltp, tspec_t lt, const tnode_t *rn, tspec_t rt) 2348 { 2349 if (rn->tn_op != CON) 2350 return; 2351 2352 if (!is_uinteger(rt) && rn->u.value.u.integer < 0) 2353 /* negative shift */ 2354 warning(121); 2355 else if ((uint64_t)rn->u.value.u.integer == size_in_bits(lt)) 2356 /* shift amount %u equals bit-size of '%s' */ 2357 warning(267, (unsigned)rn->u.value.u.integer, type_name(ltp)); 2358 else if ((uint64_t)rn->u.value.u.integer > size_in_bits(lt)) { 2359 /* shift amount %llu is greater than bit-size %llu of '%s' */ 2360 warning(122, (unsigned long long)rn->u.value.u.integer, 2361 (unsigned long long)size_in_bits(lt), 2362 tspec_name(lt)); 2363 } 2364 } 2365 2366 static bool 2367 is_typeok_eq(const tnode_t *ln, tspec_t lt, const tnode_t *rn, tspec_t rt) 2368 { 2369 if (lt == PTR && is_null_pointer(rn)) 2370 return true; 2371 if (rt == PTR && is_null_pointer(ln)) 2372 return true; 2373 return false; 2374 } 2375 2376 static void 2377 warn_incompatible_pointers(op_t op, const type_t *ltp, const type_t *rtp) 2378 { 2379 lint_assert(ltp->t_tspec == PTR); 2380 lint_assert(rtp->t_tspec == PTR); 2381 2382 tspec_t lt = ltp->t_subt->t_tspec; 2383 tspec_t rt = rtp->t_subt->t_tspec; 2384 2385 if (is_struct_or_union(lt) && is_struct_or_union(rt)) { 2386 if (op == RETURN) 2387 /* illegal structure pointer combination */ 2388 warning(244); 2389 else { 2390 /* incompatible structure pointers: '%s' '%s' '%s' */ 2391 warning(245, type_name(ltp), 2392 op_name(op), type_name(rtp)); 2393 } 2394 } else { 2395 if (op == RETURN) 2396 /* illegal combination of '%s' and '%s' */ 2397 warning(184, type_name(ltp), type_name(rtp)); 2398 else { 2399 /* illegal combination of '%s' and '%s', op '%s' */ 2400 warning(124, 2401 type_name(ltp), type_name(rtp), op_name(op)); 2402 } 2403 } 2404 } 2405 2406 static void 2407 check_pointer_comparison(op_t op, const tnode_t *ln, const tnode_t *rn) 2408 { 2409 type_t *ltp = ln->tn_type, *rtp = rn->tn_type; 2410 tspec_t lst = ltp->t_subt->t_tspec, rst = rtp->t_subt->t_tspec; 2411 2412 if (lst == VOID || rst == VOID) { 2413 /* TODO: C99 behaves like C90 here. */ 2414 if (!allow_trad && !allow_c99 && 2415 (lst == FUNC || rst == FUNC)) { 2416 /* (void *)0 is already handled in typeok() */ 2417 const char *lsts, *rsts; 2418 *(lst == FUNC ? &lsts : &rsts) = "function pointer"; 2419 *(lst == VOID ? &lsts : &rsts) = "'void *'"; 2420 /* C90 or later forbid comparison of %s with %s */ 2421 warning(274, lsts, rsts); 2422 } 2423 return; 2424 } 2425 2426 if (!types_compatible(ltp->t_subt, rtp->t_subt, true, false, NULL)) { 2427 warn_incompatible_pointers(op, ltp, rtp); 2428 return; 2429 } 2430 2431 if (lst == FUNC && rst == FUNC) { 2432 /* TODO: C99 behaves like C90 here, see C99 6.5.8p2. */ 2433 if (!allow_trad && !allow_c99 && op != EQ && op != NE) 2434 /* pointers to functions can only be compared ... */ 2435 warning(125); 2436 } 2437 } 2438 2439 static bool 2440 typeok_compare(op_t op, 2441 const tnode_t *ln, const type_t *ltp, tspec_t lt, 2442 const tnode_t *rn, const type_t *rtp, tspec_t rt) 2443 { 2444 if (lt == PTR && rt == PTR) { 2445 check_pointer_comparison(op, ln, rn); 2446 return true; 2447 } 2448 2449 if (lt != PTR && rt != PTR) 2450 return true; 2451 2452 if (!is_integer(lt) && !is_integer(rt)) { 2453 warn_incompatible_types(op, ltp, lt, rtp, rt); 2454 return false; 2455 } 2456 2457 const char *lx = lt == PTR ? "pointer" : "integer"; 2458 const char *rx = rt == PTR ? "pointer" : "integer"; 2459 /* illegal combination of %s '%s' and %s '%s', op '%s' */ 2460 warning(123, lx, type_name(ltp), rx, type_name(rtp), op_name(op)); 2461 return true; 2462 } 2463 2464 static bool 2465 typeok_quest(tspec_t lt, const tnode_t *rn) 2466 { 2467 if (!is_scalar(lt)) { 2468 /* first operand of '?' must have scalar type */ 2469 error(170); 2470 return false; 2471 } 2472 lint_assert(before_conversion(rn)->tn_op == COLON); 2473 return true; 2474 } 2475 2476 static void 2477 typeok_colon_pointer(const type_t *ltp, const type_t *rtp) 2478 { 2479 type_t *lstp = ltp->t_subt; 2480 type_t *rstp = rtp->t_subt; 2481 tspec_t lst = lstp->t_tspec; 2482 tspec_t rst = rstp->t_tspec; 2483 2484 if ((lst == VOID && rst == FUNC) || (lst == FUNC && rst == VOID)) { 2485 /* (void *)0 is handled in typeok_colon */ 2486 /* TODO: C99 behaves like C90 here. */ 2487 if (!allow_trad && !allow_c99) 2488 /* conversion of %s to %s requires a cast, op %s */ 2489 warning(305, "function pointer", "'void *'", 2490 op_name(COLON)); 2491 return; 2492 } 2493 2494 if (pointer_types_are_compatible(lstp, rstp, true)) 2495 return; 2496 if (!types_compatible(lstp, rstp, true, false, NULL)) 2497 warn_incompatible_pointers(COLON, ltp, rtp); 2498 } 2499 2500 static bool 2501 typeok_colon(const tnode_t *ln, const type_t *ltp, tspec_t lt, 2502 const tnode_t *rn, const type_t *rtp, tspec_t rt) 2503 { 2504 2505 if (is_arithmetic(lt) && is_arithmetic(rt)) 2506 return true; 2507 if (lt == BOOL && rt == BOOL) 2508 return true; 2509 2510 if (lt == STRUCT && rt == STRUCT && ltp->u.sou == rtp->u.sou) 2511 return true; 2512 if (lt == UNION && rt == UNION && ltp->u.sou == rtp->u.sou) 2513 return true; 2514 2515 if (lt == PTR && is_null_pointer(rn)) 2516 return true; 2517 if (rt == PTR && is_null_pointer(ln)) 2518 return true; 2519 2520 if ((lt == PTR && is_integer(rt)) || (is_integer(lt) && rt == PTR)) { 2521 const char *lx = lt == PTR ? "pointer" : "integer"; 2522 const char *rx = rt == PTR ? "pointer" : "integer"; 2523 /* illegal combination of %s '%s' and %s '%s', op '%s' */ 2524 warning(123, lx, type_name(ltp), 2525 rx, type_name(rtp), op_name(COLON)); 2526 return true; 2527 } 2528 2529 if (lt == VOID || rt == VOID) { 2530 if (lt != VOID || rt != VOID) 2531 /* incompatible types '%s' and '%s' in conditional */ 2532 warning(126, type_name(ltp), type_name(rtp)); 2533 return true; 2534 } 2535 2536 if (lt == PTR && rt == PTR) { 2537 typeok_colon_pointer(ltp, rtp); 2538 return true; 2539 } 2540 2541 /* incompatible types '%s' and '%s' in conditional */ 2542 error(126, type_name(ltp), type_name(rtp)); 2543 return false; 2544 } 2545 2546 static bool 2547 has_constant_member(const type_t *tp) 2548 { 2549 lint_assert(is_struct_or_union(tp->t_tspec)); 2550 2551 for (sym_t *m = tp->u.sou->sou_first_member; 2552 m != NULL; m = m->s_next) { 2553 const type_t *mtp = m->s_type; 2554 if (mtp->t_const) 2555 return true; 2556 if (is_struct_or_union(mtp->t_tspec) && 2557 has_constant_member(mtp)) 2558 return true; 2559 } 2560 return false; 2561 } 2562 2563 static bool 2564 typeok_assign(op_t op, const tnode_t *ln, const type_t *ltp, tspec_t lt) 2565 { 2566 if (op == RETURN || op == INIT || op == FARG) 2567 return true; 2568 2569 if (!ln->tn_lvalue) { 2570 if (ln->tn_op == CVT && ln->tn_cast && 2571 ln->u.ops.left->tn_op == LOAD) 2572 /* a cast does not yield an lvalue */ 2573 error(163); 2574 /* %soperand of '%s' must be lvalue */ 2575 error(114, "left ", op_name(op)); 2576 return false; 2577 } else if (ltp->t_const 2578 || (is_struct_or_union(lt) && has_constant_member(ltp))) { 2579 if (allow_c90) 2580 /* %soperand of '%s' must be modifiable lvalue */ 2581 warning(115, "left ", op_name(op)); 2582 } 2583 return true; 2584 } 2585 2586 static bool 2587 typeok_scalar(op_t op, const mod_t *mp, 2588 const type_t *ltp, tspec_t lt, 2589 const type_t *rtp, tspec_t rt) 2590 { 2591 if (mp->m_takes_bool && lt == BOOL && rt == BOOL) 2592 return true; 2593 if (mp->m_requires_integer) { 2594 if (!is_integer(lt) || (mp->m_binary && !is_integer(rt))) { 2595 warn_incompatible_types(op, ltp, lt, rtp, rt); 2596 return false; 2597 } 2598 } else if (mp->m_requires_integer_or_complex) { 2599 if ((!is_integer(lt) && !is_complex(lt)) || 2600 (mp->m_binary && (!is_integer(rt) && !is_complex(rt)))) { 2601 warn_incompatible_types(op, ltp, lt, rtp, rt); 2602 return false; 2603 } 2604 } else if (mp->m_requires_scalar) { 2605 if (!is_scalar(lt) || (mp->m_binary && !is_scalar(rt))) { 2606 warn_incompatible_types(op, ltp, lt, rtp, rt); 2607 return false; 2608 } 2609 } else if (mp->m_requires_arith) { 2610 if (!is_arithmetic(lt) || 2611 (mp->m_binary && !is_arithmetic(rt))) { 2612 warn_incompatible_types(op, ltp, lt, rtp, rt); 2613 return false; 2614 } 2615 } 2616 return true; 2617 } 2618 2619 static void 2620 check_assign_void_pointer(op_t op, int arg, 2621 tspec_t lt, tspec_t lst, 2622 tspec_t rt, tspec_t rst) 2623 { 2624 2625 if (!(lt == PTR && rt == PTR && (lst == VOID || rst == VOID))) 2626 return; 2627 /* two pointers, at least one pointer to void */ 2628 2629 /* TODO: C99 behaves like C90 here. */ 2630 if (!(!allow_trad && !allow_c99 && (lst == FUNC || rst == FUNC))) 2631 return; 2632 /* comb. of ptr to func and ptr to void */ 2633 2634 const char *lts, *rts; 2635 *(lst == FUNC ? <s : &rts) = "function pointer"; 2636 *(lst == VOID ? <s : &rts) = "'void *'"; 2637 2638 switch (op) { 2639 case INIT: 2640 case RETURN: 2641 /* conversion of %s to %s requires a cast */ 2642 warning(303, rts, lts); 2643 break; 2644 case FARG: 2645 /* conversion of %s to %s requires a cast, arg #%d */ 2646 warning(304, rts, lts, arg); 2647 break; 2648 default: 2649 /* conversion of %s to %s requires a cast, op %s */ 2650 warning(305, rts, lts, op_name(op)); 2651 break; 2652 } 2653 } 2654 2655 static bool 2656 is_direct_function_call(const tnode_t *tn, const char **out_name) 2657 { 2658 2659 if (tn->tn_op == CALL 2660 && tn->u.call->func->tn_op == ADDR 2661 && tn->u.call->func->u.ops.left->tn_op == NAME) { 2662 *out_name = tn->u.call->func->u.ops.left->u.sym->s_name; 2663 return true; 2664 } 2665 return false; 2666 } 2667 2668 static bool 2669 is_unconst_function(const char *name) 2670 { 2671 2672 return strcmp(name, "memchr") == 0 || 2673 strcmp(name, "strchr") == 0 || 2674 strcmp(name, "strpbrk") == 0 || 2675 strcmp(name, "strrchr") == 0 || 2676 strcmp(name, "strstr") == 0; 2677 } 2678 2679 static bool 2680 is_const_char_pointer(const tnode_t *tn) 2681 { 2682 /* 2683 * For traditional reasons, C99 6.4.5p5 defines that string literals 2684 * have type 'char[]'. They are often implicitly converted to 'char 2685 * *', for example when they are passed as function arguments. 2686 * 2687 * C99 6.4.5p6 further defines that modifying a string that is 2688 * constructed from a string literal invokes undefined behavior. 2689 * 2690 * Out of these reasons, string literals are treated as 'effectively 2691 * const' here. 2692 */ 2693 if (tn->tn_op == CVT && 2694 tn->u.ops.left->tn_op == ADDR && 2695 tn->u.ops.left->u.ops.left->tn_op == STRING) 2696 return true; 2697 2698 const type_t *tp = before_conversion(tn)->tn_type; 2699 return tp->t_tspec == PTR && 2700 tp->t_subt->t_tspec == CHAR && 2701 tp->t_subt->t_const; 2702 } 2703 2704 static bool 2705 is_const_pointer(const tnode_t *tn) 2706 { 2707 const type_t *tp = before_conversion(tn)->tn_type; 2708 return tp->t_tspec == PTR && tp->t_subt->t_const; 2709 } 2710 2711 static void 2712 check_unconst_function(const type_t *lstp, const tnode_t *rn) 2713 { 2714 const char *function_name; 2715 2716 if (lstp->t_tspec == CHAR && !lstp->t_const && 2717 is_direct_function_call(rn, &function_name) && 2718 is_unconst_function(function_name) && 2719 rn->u.call->args_len >= 1 && 2720 is_const_char_pointer(rn->u.call->args[0])) { 2721 /* call to '%s' effectively discards 'const' from argument */ 2722 warning(346, function_name); 2723 } 2724 2725 if (!lstp->t_const && 2726 is_direct_function_call(rn, &function_name) && 2727 strcmp(function_name, "bsearch") == 0 && 2728 rn->u.call->args_len >= 2 && 2729 is_const_pointer(rn->u.call->args[1])) { 2730 /* call to '%s' effectively discards 'const' from argument */ 2731 warning(346, function_name); 2732 } 2733 } 2734 2735 static bool 2736 check_assign_void_pointer_compat(op_t op, int arg, 2737 const type_t *ltp, tspec_t lt, 2738 const type_t *lstp, tspec_t lst, 2739 const tnode_t *rn, 2740 const type_t *rtp, tspec_t rt, 2741 const type_t *rstp, tspec_t rst) 2742 { 2743 if (!(lt == PTR && rt == PTR && (lst == VOID || rst == VOID || 2744 types_compatible(lstp, rstp, 2745 true, false, NULL)))) 2746 return false; 2747 2748 /* compatible pointer types (qualifiers ignored) */ 2749 if (allow_c90 && 2750 ((!lstp->t_const && rstp->t_const) || 2751 (!lstp->t_volatile && rstp->t_volatile))) { 2752 /* left side has not all qualifiers of right */ 2753 switch (op) { 2754 case INIT: 2755 case RETURN: 2756 /* incompatible pointer types to '%s' and '%s' */ 2757 warning(182, type_name(lstp), type_name(rstp)); 2758 break; 2759 case FARG: 2760 /* converting '%s' to incompatible '%s' ... */ 2761 warning(153, 2762 type_name(rtp), type_name(ltp), arg); 2763 break; 2764 default: 2765 /* operands of '%s' have incompatible pointer ... */ 2766 warning(128, op_name(op), 2767 type_name(lstp), type_name(rstp)); 2768 break; 2769 } 2770 } 2771 2772 if (allow_c90) 2773 check_unconst_function(lstp, rn); 2774 2775 return true; 2776 } 2777 2778 static bool 2779 check_assign_pointer_integer(op_t op, int arg, 2780 const type_t *ltp, tspec_t lt, 2781 const type_t *rtp, tspec_t rt) 2782 { 2783 2784 if (!((lt == PTR && is_integer(rt)) || (is_integer(lt) && rt == PTR))) 2785 return false; 2786 2787 const char *lx = lt == PTR ? "pointer" : "integer"; 2788 const char *rx = rt == PTR ? "pointer" : "integer"; 2789 2790 switch (op) { 2791 case INIT: 2792 case RETURN: 2793 /* illegal combination of %s '%s' and %s '%s' */ 2794 warning(183, lx, type_name(ltp), rx, type_name(rtp)); 2795 break; 2796 case FARG: 2797 /* illegal combination of %s '%s' and %s '%s', arg #%d */ 2798 warning(154, 2799 lx, type_name(ltp), rx, type_name(rtp), arg); 2800 break; 2801 default: 2802 /* illegal combination of %s '%s' and %s '%s', op '%s' */ 2803 warning(123, 2804 lx, type_name(ltp), rx, type_name(rtp), op_name(op)); 2805 break; 2806 } 2807 return true; 2808 } 2809 2810 static bool 2811 check_assign_pointer(op_t op, int arg, 2812 const type_t *ltp, tspec_t lt, 2813 const type_t *rtp, tspec_t rt) 2814 { 2815 if (!(lt == PTR && rt == PTR)) 2816 return false; 2817 2818 if (op == FARG) 2819 /* converting '%s' to incompatible '%s' for ... */ 2820 warning(153, type_name(rtp), type_name(ltp), arg); 2821 else 2822 warn_incompatible_pointers(op, ltp, rtp); 2823 return true; 2824 } 2825 2826 static void 2827 warn_assign(op_t op, int arg, 2828 const type_t *ltp, tspec_t lt, 2829 const type_t *rtp, tspec_t rt) 2830 { 2831 switch (op) { 2832 case INIT: 2833 /* cannot initialize '%s' from '%s' */ 2834 error(185, type_name(ltp), type_name(rtp)); 2835 break; 2836 case RETURN: 2837 /* function has return type '%s' but returns '%s' */ 2838 error(211, type_name(ltp), type_name(rtp)); 2839 break; 2840 case FARG: 2841 /* passing '%s' to incompatible '%s', arg #%d */ 2842 warning(155, type_name(rtp), type_name(ltp), arg); 2843 break; 2844 default: 2845 warn_incompatible_types(op, ltp, lt, rtp, rt); 2846 break; 2847 } 2848 } 2849 2850 /* 2851 * Checks type compatibility for ASSIGN, INIT, FARG and RETURN 2852 * and prints warnings/errors if necessary. 2853 * Returns whether the types are (almost) compatible. 2854 */ 2855 static bool 2856 check_assign_types_compatible(op_t op, int arg, 2857 const tnode_t *ln, const tnode_t *rn) 2858 { 2859 tspec_t lt, rt, lst = NO_TSPEC, rst = NO_TSPEC; 2860 type_t *ltp, *rtp, *lstp = NULL, *rstp = NULL; 2861 2862 if ((lt = (ltp = ln->tn_type)->t_tspec) == PTR) 2863 lst = (lstp = ltp->t_subt)->t_tspec; 2864 if ((rt = (rtp = rn->tn_type)->t_tspec) == PTR) 2865 rst = (rstp = rtp->t_subt)->t_tspec; 2866 2867 if (lt == BOOL && is_scalar(rt)) /* C99 6.3.1.2 */ 2868 return true; 2869 2870 if (is_arithmetic(lt) && (is_arithmetic(rt) || rt == BOOL)) 2871 return true; 2872 2873 if (is_struct_or_union(lt) && is_struct_or_union(rt)) 2874 return ltp->u.sou == rtp->u.sou; 2875 2876 if (lt == PTR && is_null_pointer(rn)) { 2877 if (is_integer(rn->tn_type->t_tspec)) 2878 /* implicit conversion from integer 0 to pointer ... */ 2879 query_message(15, type_name(ltp)); 2880 return true; 2881 } 2882 2883 check_assign_void_pointer(op, arg, lt, lst, rt, rst); 2884 2885 if (check_assign_void_pointer_compat(op, arg, 2886 ltp, lt, lstp, lst, rn, rtp, rt, rstp, rst)) 2887 return true; 2888 2889 if (check_assign_pointer_integer(op, arg, ltp, lt, rtp, rt)) 2890 return true; 2891 2892 if (check_assign_pointer(op, arg, ltp, lt, rtp, rt)) 2893 return true; 2894 2895 warn_assign(op, arg, ltp, lt, rtp, rt); 2896 return false; 2897 } 2898 2899 static bool 2900 has_side_effect(const tnode_t *tn) /* NOLINT(misc-no-recursion) */ 2901 { 2902 op_t op = tn->tn_op; 2903 2904 if (modtab[op].m_has_side_effect) 2905 return true; 2906 2907 if (op == CVT && tn->tn_type->t_tspec == VOID) 2908 return has_side_effect(tn->u.ops.left); 2909 2910 /* XXX: Why not has_side_effect(tn->u.ops.left) as well? */ 2911 if (op == LOGAND || op == LOGOR) 2912 return has_side_effect(tn->u.ops.right); 2913 2914 /* XXX: Why not has_side_effect(tn->u.ops.left) as well? */ 2915 if (op == QUEST) 2916 return has_side_effect(tn->u.ops.right); 2917 2918 if (op == COLON || op == COMMA) { 2919 return has_side_effect(tn->u.ops.left) || 2920 has_side_effect(tn->u.ops.right); 2921 } 2922 2923 return false; 2924 } 2925 2926 static bool 2927 is_void_cast(const tnode_t *tn) 2928 { 2929 2930 return tn->tn_op == CVT && tn->tn_cast && 2931 tn->tn_type->t_tspec == VOID; 2932 } 2933 2934 static bool 2935 is_local_symbol(const tnode_t *tn) 2936 { 2937 2938 return tn->tn_op == LOAD && 2939 tn->u.ops.left->tn_op == NAME && 2940 tn->u.ops.left->u.sym->s_scl == AUTO; 2941 } 2942 2943 static bool 2944 is_int_constant_zero(const tnode_t *tn) 2945 { 2946 2947 return tn->tn_op == CON && 2948 tn->tn_type->t_tspec == INT && 2949 tn->u.value.u.integer == 0; 2950 } 2951 2952 static void 2953 check_null_effect(const tnode_t *tn) 2954 { 2955 2956 if (hflag && 2957 !has_side_effect(tn) && 2958 !(is_void_cast(tn) && is_local_symbol(tn->u.ops.left)) && 2959 !(is_void_cast(tn) && is_int_constant_zero(tn->u.ops.left))) { 2960 /* expression has null effect */ 2961 warning(129); 2962 } 2963 } 2964 2965 /* 2966 * Check the types for specific operators and type combinations. 2967 * 2968 * At this point, the operands already conform to the type requirements of 2969 * the operator, such as being integer, floating or scalar. 2970 */ 2971 static bool 2972 typeok_op(op_t op, int arg, 2973 const tnode_t *ln, const type_t *ltp, tspec_t lt, 2974 const tnode_t *rn, const type_t *rtp, tspec_t rt) 2975 { 2976 switch (op) { 2977 case ARROW: 2978 return typeok_arrow(lt); 2979 case POINT: 2980 return typeok_point(ln, ltp, lt); 2981 case INCBEF: 2982 case DECBEF: 2983 case INCAFT: 2984 case DECAFT: 2985 return typeok_incdec(op, ln, ltp); 2986 case INDIR: 2987 return typeok_indir(ltp, lt); 2988 case ADDR: 2989 return typeok_address(op, ln, ltp, lt); 2990 case PLUS: 2991 return typeok_plus(op, ltp, lt, rtp, rt); 2992 case MINUS: 2993 return typeok_minus(op, ltp, lt, rtp, rt); 2994 case SHL: 2995 typeok_shl(op, lt, rt); 2996 goto shift; 2997 case SHR: 2998 typeok_shr(op, ln, lt, rn, rt); 2999 shift: 3000 typeok_shift(ltp, lt, rn, rt); 3001 break; 3002 case LT: 3003 case LE: 3004 case GT: 3005 case GE: 3006 compare: 3007 return typeok_compare(op, ln, ltp, lt, rn, rtp, rt); 3008 case EQ: 3009 case NE: 3010 if (is_typeok_eq(ln, lt, rn, rt)) 3011 break; 3012 goto compare; 3013 case QUEST: 3014 return typeok_quest(lt, rn); 3015 case COLON: 3016 return typeok_colon(ln, ltp, lt, rn, rtp, rt); 3017 case ASSIGN: 3018 case INIT: 3019 case FARG: 3020 case RETURN: 3021 if (!check_assign_types_compatible(op, arg, ln, rn)) 3022 return false; 3023 goto assign; 3024 case MULASS: 3025 case DIVASS: 3026 case MODASS: 3027 goto assign; 3028 case ADDASS: 3029 case SUBASS: 3030 if ((lt == PTR && !is_integer(rt)) || rt == PTR) { 3031 warn_incompatible_types(op, ltp, lt, rtp, rt); 3032 return false; 3033 } 3034 goto assign; 3035 case SHLASS: 3036 goto assign; 3037 case SHRASS: 3038 if (pflag && !is_uinteger(lt) && 3039 !(!allow_c90 && is_uinteger(rt))) { 3040 /* bitwise '%s' on signed value possibly nonportable */ 3041 warning(117, op_name(op)); 3042 } 3043 goto assign; 3044 case ANDASS: 3045 case XORASS: 3046 case ORASS: 3047 assign: 3048 return typeok_assign(op, ln, ltp, lt); 3049 case COMMA: 3050 if (!modtab[ln->tn_op].m_has_side_effect) 3051 check_null_effect(ln); 3052 break; 3053 default: 3054 break; 3055 } 3056 return true; 3057 } 3058 3059 static void 3060 check_bad_enum_operation(op_t op, const tnode_t *ln, const tnode_t *rn) 3061 { 3062 3063 if (!eflag) 3064 return; 3065 3066 /* Allow enum in array indices. */ 3067 if (op == PLUS && 3068 ((ln->tn_type->t_is_enum && rn->tn_type->t_tspec == PTR) || 3069 (rn->tn_type->t_is_enum && ln->tn_type->t_tspec == PTR))) { 3070 return; 3071 } 3072 3073 /* dubious operation '%s' on enum */ 3074 warning(241, op_name(op)); 3075 } 3076 3077 static void 3078 check_enum_type_mismatch(op_t op, int arg, const tnode_t *ln, const tnode_t *rn) 3079 { 3080 const mod_t *mp = &modtab[op]; 3081 3082 if (ln->tn_type->u.enumer != rn->tn_type->u.enumer) { 3083 switch (op) { 3084 case INIT: 3085 /* enum type mismatch between '%s' and '%s' in ... */ 3086 warning(210, 3087 type_name(ln->tn_type), type_name(rn->tn_type)); 3088 break; 3089 case FARG: 3090 /* function expects '%s', passing '%s' for arg #%d */ 3091 warning(156, 3092 type_name(ln->tn_type), type_name(rn->tn_type), 3093 arg); 3094 break; 3095 case RETURN: 3096 /* function has return type '%s' but returns '%s' */ 3097 warning(211, 3098 type_name(ln->tn_type), type_name(rn->tn_type)); 3099 break; 3100 default: 3101 /* enum type mismatch: '%s' '%s' '%s' */ 3102 warning(130, type_name(ln->tn_type), op_name(op), 3103 type_name(rn->tn_type)); 3104 break; 3105 } 3106 } else if (Pflag && eflag && mp->m_comparison && op != EQ && op != NE) 3107 /* operator '%s' assumes that '%s' is ordered */ 3108 warning(243, op_name(op), type_name(ln->tn_type)); 3109 } 3110 3111 static void 3112 check_enum_int_mismatch(op_t op, int arg, const tnode_t *ln, const tnode_t *rn) 3113 { 3114 3115 if (!eflag) 3116 return; 3117 3118 switch (op) { 3119 case INIT: 3120 /* 3121 * Initialization with 0 is allowed. Otherwise, all implicit 3122 * initializations would need to be warned upon as well. 3123 */ 3124 if (!rn->tn_type->t_is_enum && rn->tn_op == CON && 3125 is_integer(rn->tn_type->t_tspec) && 3126 rn->u.value.u.integer == 0) { 3127 return; 3128 } 3129 /* initialization of '%s' with '%s' */ 3130 warning(277, type_name(ln->tn_type), type_name(rn->tn_type)); 3131 break; 3132 case FARG: 3133 /* combination of '%s' and '%s', arg #%d */ 3134 warning(278, 3135 type_name(ln->tn_type), type_name(rn->tn_type), arg); 3136 break; 3137 case RETURN: 3138 /* combination of '%s' and '%s' in return */ 3139 warning(279, type_name(ln->tn_type), type_name(rn->tn_type)); 3140 break; 3141 default: 3142 /* combination of '%s' and '%s', op '%s' */ 3143 warning(242, type_name(ln->tn_type), type_name(rn->tn_type), 3144 op_name(op)); 3145 break; 3146 } 3147 } 3148 3149 static void 3150 typeok_enum(op_t op, const mod_t *mp, int arg, 3151 const tnode_t *ln, const type_t *ltp, 3152 const tnode_t *rn, const type_t *rtp) 3153 { 3154 if (mp->m_bad_on_enum && 3155 (ltp->t_is_enum || (mp->m_binary && rtp->t_is_enum))) { 3156 check_bad_enum_operation(op, ln, rn); 3157 } else if (mp->m_valid_on_enum && 3158 (ltp->t_is_enum && rtp != NULL && rtp->t_is_enum)) { 3159 check_enum_type_mismatch(op, arg, ln, rn); 3160 } else if (mp->m_valid_on_enum && 3161 (ltp->t_is_enum || (rtp != NULL && rtp->t_is_enum))) { 3162 check_enum_int_mismatch(op, arg, ln, rn); 3163 } 3164 } 3165 3166 /* Perform most type checks. Return whether the types are ok. */ 3167 bool 3168 typeok(op_t op, int arg, const tnode_t *ln, const tnode_t *rn) 3169 { 3170 3171 const mod_t *mp = &modtab[op]; 3172 3173 type_t *ltp = ln->tn_type; 3174 tspec_t lt = ltp->t_tspec; 3175 3176 type_t *rtp = mp->m_binary ? rn->tn_type : NULL; 3177 tspec_t rt = mp->m_binary ? rtp->t_tspec : NO_TSPEC; 3178 3179 if (Tflag && !typeok_scalar_strict_bool(op, mp, arg, ln, rn)) 3180 return false; 3181 if (!typeok_scalar(op, mp, ltp, lt, rtp, rt)) 3182 return false; 3183 3184 if (!typeok_op(op, arg, ln, ltp, lt, rn, rtp, rt)) 3185 return false; 3186 3187 typeok_enum(op, mp, arg, ln, ltp, rn, rtp); 3188 return true; 3189 } 3190 3191 /* In traditional C, keep unsigned and promote FLOAT to DOUBLE. */ 3192 static tspec_t 3193 promote_trad(tspec_t t) 3194 { 3195 3196 if (t == UCHAR || t == USHORT) 3197 return UINT; 3198 if (t == CHAR || t == SCHAR || t == SHORT) 3199 return INT; 3200 if (t == FLOAT) 3201 return DOUBLE; 3202 if (t == ENUM) 3203 return INT; 3204 return t; 3205 } 3206 3207 /* 3208 * C99 6.3.1.1p2 requires for types with lower rank than int that "If an int 3209 * can represent all the values of the original type, the value is converted 3210 * to an int; otherwise it is converted to an unsigned int", and that "All 3211 * other types are unchanged by the integer promotions". 3212 */ 3213 static tspec_t 3214 promote_c90(const tnode_t *tn, tspec_t t, bool farg) 3215 { 3216 if (tn->tn_type->t_bitfield) { 3217 unsigned int width = tn->tn_type->t_bit_field_width; 3218 unsigned int int_width = size_in_bits(INT); 3219 // XXX: What about _Bool bit-fields, since C99? 3220 if (width < int_width) 3221 return INT; 3222 if (width == int_width) 3223 return is_uinteger(t) ? UINT : INT; 3224 return t; 3225 } 3226 3227 if (t == CHAR || t == SCHAR) 3228 return INT; 3229 if (t == UCHAR) 3230 return size_in_bits(CHAR) < size_in_bits(INT) ? INT : UINT; 3231 if (t == SHORT) 3232 return INT; 3233 if (t == USHORT) 3234 return size_in_bits(SHORT) < size_in_bits(INT) ? INT : UINT; 3235 if (t == ENUM) 3236 return INT; 3237 if (farg && t == FLOAT) 3238 return DOUBLE; 3239 return t; 3240 } 3241 3242 /* 3243 * Performs the "integer promotions" (C99 6.3.1.1p2), which convert small 3244 * integer types to either int or unsigned int. 3245 * 3246 * If allow_c90 is unset or the operand is a function argument with no type 3247 * information (no prototype or variable # of args), converts float to double. 3248 */ 3249 tnode_t * 3250 promote(op_t op, bool farg, tnode_t *tn) 3251 { 3252 3253 const type_t *otp = tn->tn_type; 3254 tspec_t ot = otp->t_tspec; 3255 if (!is_arithmetic(ot)) 3256 return tn; 3257 3258 tspec_t nt = allow_c90 ? promote_c90(tn, ot, farg) : promote_trad(ot); 3259 if (nt == ot) 3260 return tn; 3261 3262 type_t *ntp = expr_dup_type(gettyp(nt)); 3263 ntp->t_tspec = nt; 3264 ntp->t_is_enum = otp->t_is_enum; 3265 if (ntp->t_is_enum) 3266 ntp->u.enumer = otp->u.enumer; 3267 ntp->t_bitfield = otp->t_bitfield; 3268 if (ntp->t_bitfield) { 3269 ntp->t_bit_field_width = otp->t_bit_field_width; 3270 ntp->t_bit_field_offset = otp->t_bit_field_offset; 3271 } 3272 if (ntp->t_bitfield && is_uinteger(ot) && !is_uinteger(nt)) 3273 ntp->t_bit_field_width++; 3274 return convert(op, 0, ntp, tn); 3275 } 3276 3277 static void 3278 convert_integer_from_floating(op_t op, const type_t *tp, const tnode_t *tn) 3279 { 3280 3281 if (op == CVT) 3282 /* cast from floating point '%s' to integer '%s' */ 3283 query_message(2, type_name(tn->tn_type), type_name(tp)); 3284 else 3285 /* implicit conversion from floating point '%s' to ... */ 3286 query_message(1, type_name(tn->tn_type), type_name(tp)); 3287 } 3288 3289 static bool 3290 should_warn_about_prototype_conversion(tspec_t nt, 3291 tspec_t ot, const tnode_t *ptn) 3292 { 3293 3294 if (nt == ot) 3295 return false; 3296 3297 if (nt == ENUM && ot == INT) 3298 return false; 3299 3300 if (is_floating(nt) != is_floating(ot) || 3301 portable_rank_cmp(nt, ot) != 0) { 3302 /* representation and/or width change */ 3303 if (!is_integer(ot)) 3304 return true; 3305 /* 3306 * XXX: Investigate whether this rule makes sense; see 3307 * tests/usr.bin/xlint/lint1/platform_long.c. 3308 */ 3309 return portable_rank_cmp(ot, INT) > 0; 3310 } 3311 3312 if (!hflag) 3313 return false; 3314 3315 /* 3316 * If the types differ only in sign and the argument has the same 3317 * representation in both types, print no warning. 3318 */ 3319 if (ptn->tn_op == CON && is_integer(nt) && 3320 signed_type(nt) == signed_type(ot) && 3321 !msb(ptn->u.value.u.integer, ot)) 3322 return false; 3323 3324 return true; 3325 } 3326 3327 /* 3328 * Warn if a prototype causes a type conversion that is different from what 3329 * would happen to the same argument in the absence of a prototype. This 3330 * check is intended for code that needs to stay compatible with pre-C90 C. 3331 * 3332 * Errors/warnings about illegal type combinations are already printed 3333 * in check_assign_types_compatible(). 3334 */ 3335 static void 3336 check_prototype_conversion(int arg, tspec_t nt, tspec_t ot, type_t *tp, 3337 tnode_t *tn) 3338 { 3339 3340 if (!is_arithmetic(nt) || !is_arithmetic(ot)) 3341 return; 3342 3343 /* 3344 * If the type of the formal parameter is char/short, a warning would 3345 * be useless, because functions declared the old style can't expect 3346 * char/short arguments. 3347 */ 3348 if (nt == CHAR || nt == SCHAR || nt == UCHAR || 3349 nt == SHORT || nt == USHORT) 3350 return; 3351 3352 tnode_t *ptn = promote(NOOP, true, tn); 3353 ot = ptn->tn_type->t_tspec; 3354 3355 if (should_warn_about_prototype_conversion(nt, ot, ptn)) { 3356 /* argument %d is converted from '%s' to '%s' ... */ 3357 warning(259, arg, type_name(tn->tn_type), type_name(tp)); 3358 } 3359 } 3360 3361 /* 3362 * When converting a large integer type to a small integer type, in some 3363 * cases the value of the actual expression is further restricted than the 3364 * type bounds, such as in (expr & 0xFF) or (expr % 100) or (expr >> 24). 3365 */ 3366 static bool 3367 can_represent(const type_t *tp, const tnode_t *tn) 3368 { 3369 3370 debug_step("%s: type '%s'", __func__, type_name(tp)); 3371 debug_node(tn); 3372 3373 uint64_t nmask = value_bits(width_in_bits(tp)); 3374 if (!is_uinteger(tp->t_tspec)) 3375 nmask >>= 1; 3376 3377 integer_constraints c = ic_expr(tn); 3378 if ((~c.bclr & ~nmask) == 0) 3379 return true; 3380 3381 integer_constraints tpc = ic_any(tp); 3382 if (is_uinteger(tp->t_tspec) 3383 ? tpc.umin <= c.umin && tpc.umax >= c.umax 3384 : tpc.smin <= c.smin && tpc.smax >= c.smax) 3385 return true; 3386 3387 return false; 3388 } 3389 3390 static bool 3391 should_warn_about_integer_conversion(const type_t *ntp, tspec_t nt, 3392 const tnode_t *otn, tspec_t ot) 3393 { 3394 3395 // XXX: The portable_rank_cmp aims at portable mode, independent of the 3396 // current platform, while can_represent acts on the actual type sizes 3397 // from the current platform. This mix is inconsistent, but anything 3398 // else would make the exact conditions too complicated to grasp. 3399 if (aflag > 0 && portable_rank_cmp(nt, ot) < 0) { 3400 if (ot == LONG || ot == ULONG 3401 || ot == LLONG || ot == ULLONG 3402 #ifdef INT128_SIZE 3403 || ot == INT128 || ot == UINT128 3404 #endif 3405 || aflag > 1) 3406 return !can_represent(ntp, otn); 3407 } 3408 return false; 3409 } 3410 3411 static void 3412 convert_integer_from_integer(op_t op, int arg, tspec_t nt, tspec_t ot, 3413 type_t *tp, tnode_t *tn) 3414 { 3415 3416 if (tn->tn_op == CON) 3417 return; 3418 3419 if (op == CVT) 3420 return; 3421 3422 if (Pflag && pflag && aflag > 0 && 3423 portable_rank_cmp(nt, ot) > 0 && 3424 is_uinteger(nt) != is_uinteger(ot)) { 3425 if (op == FARG) 3426 /* conversion to '%s' may sign-extend ... */ 3427 warning(297, type_name(tp), arg); 3428 else 3429 /* conversion to '%s' may sign-extend ... */ 3430 warning(131, type_name(tp)); 3431 } 3432 3433 if (Pflag && portable_rank_cmp(nt, ot) > 0 && 3434 (tn->tn_op == PLUS || tn->tn_op == MINUS || tn->tn_op == MULT || 3435 tn->tn_op == SHL)) { 3436 /* suggest cast from '%s' to '%s' on op '%s' to ... */ 3437 warning(324, type_name(gettyp(ot)), type_name(tp), 3438 op_name(tn->tn_op)); 3439 } 3440 3441 if (should_warn_about_integer_conversion(tp, nt, tn, ot)) { 3442 if (op == FARG) { 3443 /* conversion from '%s' to '%s' may lose ... */ 3444 warning(298, 3445 type_name(tn->tn_type), type_name(tp), arg); 3446 } else { 3447 /* conversion from '%s' to '%s' may lose accuracy */ 3448 warning(132, 3449 type_name(tn->tn_type), type_name(tp)); 3450 } 3451 } 3452 3453 if (any_query_enabled && is_uinteger(nt) != is_uinteger(ot)) 3454 /* implicit conversion changes sign from '%s' to '%s' */ 3455 query_message(3, type_name(tn->tn_type), type_name(tp)); 3456 } 3457 3458 static void 3459 convert_integer_from_pointer(op_t op, tspec_t nt, type_t *tp, tnode_t *tn) 3460 { 3461 3462 if (tn->tn_op == CON) 3463 return; 3464 if (op != CVT) 3465 return; /* We already got an error. */ 3466 if (portable_rank_cmp(nt, PTR) >= 0) 3467 return; 3468 3469 if (pflag && size_in_bits(nt) >= size_in_bits(PTR)) { 3470 /* conversion of pointer to '%s' may lose bits */ 3471 warning(134, type_name(tp)); 3472 } else { 3473 /* conversion of pointer to '%s' loses bits */ 3474 warning(133, type_name(tp)); 3475 } 3476 } 3477 3478 static bool 3479 struct_starts_with(const type_t *struct_tp, const type_t *member_tp) 3480 { 3481 3482 return struct_tp->u.sou->sou_first_member != NULL && 3483 types_compatible(struct_tp->u.sou->sou_first_member->s_type, 3484 member_tp, true, false, NULL); 3485 } 3486 3487 static bool 3488 is_byte_array(const type_t *tp) 3489 { 3490 3491 return tp->t_tspec == ARRAY && 3492 (tp->t_subt->t_tspec == CHAR || tp->t_subt->t_tspec == UCHAR); 3493 } 3494 3495 static bool 3496 union_contains(const type_t *utp, const type_t *mtp) 3497 { 3498 for (const sym_t *mem = utp->u.sou->sou_first_member; 3499 mem != NULL; mem = mem->s_next) { 3500 if (types_compatible(mem->s_type, mtp, true, false, NULL)) 3501 return true; 3502 } 3503 return false; 3504 } 3505 3506 static bool 3507 should_warn_about_pointer_cast(const type_t *nstp, tspec_t nst, 3508 const type_t *ostp, tspec_t ost) 3509 { 3510 3511 while (nst == ARRAY) 3512 nstp = nstp->t_subt, nst = nstp->t_tspec; 3513 while (ost == ARRAY) 3514 ostp = ostp->t_subt, ost = ostp->t_tspec; 3515 3516 if (nst == STRUCT && ost == STRUCT && 3517 (struct_starts_with(nstp, ostp) || 3518 struct_starts_with(ostp, nstp))) 3519 return false; 3520 3521 if (is_incomplete(nstp) || is_incomplete(ostp)) 3522 return false; 3523 3524 if (nst == CHAR || nst == UCHAR) 3525 return false; /* for the sake of traditional C code */ 3526 if (ost == CHAR || ost == UCHAR) 3527 return false; /* for the sake of traditional C code */ 3528 3529 /* Allow cast between pointers to sockaddr variants. */ 3530 if (nst == STRUCT && ost == STRUCT) { 3531 const sym_t *nmem = nstp->u.sou->sou_first_member; 3532 const sym_t *omem = ostp->u.sou->sou_first_member; 3533 while (nmem != NULL && omem != NULL && 3534 types_compatible(nmem->s_type, omem->s_type, 3535 true, false, NULL)) 3536 nmem = nmem->s_next, omem = omem->s_next; 3537 if (nmem != NULL && is_byte_array(nmem->s_type)) 3538 return false; 3539 if (omem != NULL && is_byte_array(omem->s_type)) 3540 return false; 3541 if (nmem == NULL && omem == NULL) 3542 return false; 3543 } 3544 3545 if (nst == UNION || ost == UNION) { 3546 const type_t *union_tp = nst == UNION ? nstp : ostp; 3547 const type_t *other_tp = nst == UNION ? ostp : nstp; 3548 if (union_contains(union_tp, other_tp)) 3549 return false; 3550 } 3551 3552 if (is_struct_or_union(nst) && is_struct_or_union(ost)) 3553 return nstp->u.sou != ostp->u.sou; 3554 3555 enum rank_kind rk1 = type_properties(nst)->tt_rank_kind; 3556 enum rank_kind rk2 = type_properties(ost)->tt_rank_kind; 3557 if (rk1 != rk2 || rk1 == RK_NONE) 3558 return true; 3559 3560 return portable_rank_cmp(nst, ost) != 0; 3561 } 3562 3563 static void 3564 convert_pointer_from_pointer(type_t *ntp, tnode_t *tn) 3565 { 3566 const type_t *nstp = ntp->t_subt; 3567 const type_t *otp = tn->tn_type; 3568 const type_t *ostp = otp->t_subt; 3569 tspec_t nst = nstp->t_tspec; 3570 tspec_t ost = ostp->t_tspec; 3571 3572 if (nst == VOID || ost == VOID) { 3573 /* TODO: C99 behaves like C90 here. */ 3574 if (!allow_trad && !allow_c99 && (nst == FUNC || ost == FUNC)) { 3575 const char *nts, *ots; 3576 /* null pointers are already handled in convert() */ 3577 *(nst == FUNC ? &nts : &ots) = "function pointer"; 3578 *(nst == VOID ? &nts : &ots) = "'void *'"; 3579 /* conversion of %s to %s requires a cast */ 3580 warning(303, ots, nts); 3581 } 3582 return; 3583 } 3584 if (nst == FUNC && ost == FUNC) 3585 return; 3586 if (nst == FUNC || ost == FUNC) { 3587 /* converting '%s' to '%s' is questionable */ 3588 warning(229, type_name(otp), type_name(ntp)); 3589 return; 3590 } 3591 3592 if (hflag && alignment_in_bits(nstp) > alignment_in_bits(ostp) && 3593 ost != CHAR && ost != UCHAR && 3594 !is_incomplete(ostp) && 3595 !(nst == UNION && union_contains(nstp, ostp))) { 3596 /* converting '%s' to '%s' increases alignment ... */ 3597 warning(135, type_name(otp), type_name(ntp), 3598 alignment_in_bits(ostp) / CHAR_SIZE, 3599 alignment_in_bits(nstp) / CHAR_SIZE); 3600 } 3601 3602 if (cflag && should_warn_about_pointer_cast(nstp, nst, ostp, ost)) { 3603 /* pointer cast from '%s' to '%s' may be troublesome */ 3604 warning(247, type_name(otp), type_name(ntp)); 3605 } 3606 } 3607 3608 /* 3609 * Insert a conversion operator, which converts the type of the node 3610 * to another given type. 3611 * 3612 * Possible values for 'op': 3613 * CVT a cast-expression 3614 * binary integer promotion for one of the operands, or a usual 3615 * arithmetic conversion 3616 * binary plain or compound assignments to bit-fields 3617 * FARG 'arg' is the number of the parameter (used for warnings) 3618 * NOOP several other implicit conversions 3619 * ... 3620 */ 3621 tnode_t * 3622 convert(op_t op, int arg, type_t *tp, tnode_t *tn) 3623 { 3624 tspec_t nt = tp->t_tspec; 3625 tspec_t ot = tn->tn_type->t_tspec; 3626 3627 if (allow_trad && allow_c90 && op == FARG) 3628 check_prototype_conversion(arg, nt, ot, tp, tn); 3629 3630 if (nt == BOOL) { 3631 /* No further checks. */ 3632 3633 } else if (is_integer(nt)) { 3634 if (ot == BOOL) { 3635 /* No further checks. */ 3636 } else if (is_integer(ot)) 3637 convert_integer_from_integer(op, arg, nt, ot, tp, tn); 3638 else if (is_floating(ot)) 3639 convert_integer_from_floating(op, tp, tn); 3640 else if (ot == PTR) 3641 convert_integer_from_pointer(op, nt, tp, tn); 3642 3643 } else if (is_floating(nt)) { 3644 if (is_integer(ot) && op != CVT) { 3645 /* implicit conversion from integer '%s' to ... */ 3646 query_message(19, 3647 type_name(tn->tn_type), type_name(tp)); 3648 } 3649 3650 } else if (nt == PTR) { 3651 if (is_null_pointer(tn)) { 3652 /* a null pointer may be assigned to any pointer. */ 3653 } else if (ot == PTR && op == CVT) 3654 convert_pointer_from_pointer(tp, tn); 3655 } 3656 3657 tnode_t *ntn = expr_alloc_tnode(); 3658 ntn->tn_op = CVT; 3659 ntn->tn_type = tp; 3660 ntn->tn_cast = op == CVT; 3661 ntn->tn_sys |= tn->tn_sys; 3662 ntn->u.ops.right = NULL; 3663 if (tn->tn_op != CON || nt == VOID) { 3664 ntn->u.ops.left = tn; 3665 } else { 3666 ntn->tn_op = CON; 3667 convert_constant(op, arg, ntn->tn_type, &ntn->u.value, 3668 &tn->u.value); 3669 } 3670 3671 return ntn; 3672 } 3673 3674 static void 3675 convert_constant_floating(op_t op, int arg, tspec_t ot, const type_t *tp, 3676 tspec_t nt, val_t *v, val_t *nv) 3677 { 3678 long double max = 0.0, min = 0.0; 3679 3680 switch (nt) { 3681 case CHAR: 3682 max = TARG_CHAR_MAX; min = TARG_CHAR_MIN; break; 3683 case UCHAR: 3684 max = TARG_UCHAR_MAX; min = 0; break; 3685 case SCHAR: 3686 max = TARG_SCHAR_MAX; min = TARG_SCHAR_MIN; break; 3687 case SHORT: 3688 max = TARG_SHRT_MAX; min = TARG_SHRT_MIN; break; 3689 case USHORT: 3690 max = TARG_USHRT_MAX; min = 0; break; 3691 case ENUM: 3692 case INT: 3693 max = TARG_INT_MAX; min = TARG_INT_MIN; break; 3694 case UINT: 3695 max = TARG_UINT_MAX; min = 0; break; 3696 case LONG: 3697 max = TARG_LONG_MAX; min = TARG_LONG_MIN; break; 3698 case ULONG: 3699 max = TARG_ULONG_MAX; min = 0; break; 3700 case LLONG: 3701 max = LLONG_MAX; min = LLONG_MIN; break; 3702 case ULLONG: 3703 max = ULLONG_MAX; min = 0; break; 3704 case FLOAT: 3705 case FCOMPLEX: 3706 max = FLT_MAX; min = -FLT_MAX; break; 3707 case DOUBLE: 3708 case DCOMPLEX: 3709 max = DBL_MAX; min = -DBL_MAX; break; 3710 case PTR: 3711 /* Already got an error because of float --> ptr */ 3712 case LDOUBLE: 3713 case LCOMPLEX: 3714 /* LINTED 248 */ 3715 max = LDBL_MAX; min = -max; break; 3716 default: 3717 lint_assert(/*CONSTCOND*/false); 3718 } 3719 if (v->u.floating > max || v->u.floating < min) { 3720 lint_assert(nt != LDOUBLE); 3721 if (op == FARG) { 3722 /* conversion of '%s' to '%s' is out of range, ... */ 3723 warning(295, 3724 type_name(gettyp(ot)), type_name(tp), arg); 3725 } else { 3726 /* conversion of '%s' to '%s' is out of range */ 3727 warning(119, type_name(gettyp(ot)), type_name(tp)); 3728 } 3729 v->u.floating = v->u.floating > 0 ? max : min; 3730 } 3731 3732 if (nt == FLOAT || nt == FCOMPLEX) 3733 nv->u.floating = (float)v->u.floating; 3734 else if (nt == DOUBLE || nt == DCOMPLEX) 3735 nv->u.floating = (double)v->u.floating; 3736 else if (nt == LDOUBLE || nt == LCOMPLEX) 3737 nv->u.floating = v->u.floating; 3738 else 3739 nv->u.integer = (int64_t)v->u.floating; 3740 } 3741 3742 static bool 3743 convert_constant_to_floating(tspec_t nt, val_t *nv, 3744 tspec_t ot, const val_t *v) 3745 { 3746 if (nt == FLOAT) { 3747 nv->u.floating = (ot == PTR || is_uinteger(ot)) ? 3748 (float)(uint64_t)v->u.integer : (float)v->u.integer; 3749 } else if (nt == DOUBLE) { 3750 nv->u.floating = (ot == PTR || is_uinteger(ot)) ? 3751 (double)(uint64_t)v->u.integer : (double)v->u.integer; 3752 } else if (nt == LDOUBLE) { 3753 nv->u.floating = (ot == PTR || is_uinteger(ot)) 3754 ? (long double)(uint64_t)v->u.integer 3755 : (long double)v->u.integer; 3756 } else 3757 return false; 3758 return true; 3759 } 3760 3761 /* 3762 * Print a warning if bits which were set are lost due to the conversion. 3763 * This can happen with operator ORASS only. 3764 */ 3765 static void 3766 convert_constant_check_range_bitor(size_t nsz, size_t osz, const val_t *v, 3767 uint64_t xmask, op_t op) 3768 { 3769 if (nsz < osz && (v->u.integer & xmask) != 0) 3770 /* constant truncated by conversion, op '%s' */ 3771 warning(306, op_name(op)); 3772 } 3773 3774 static void 3775 convert_constant_check_range_bitand(size_t nsz, size_t osz, 3776 uint64_t xmask, const val_t *nv, 3777 tspec_t ot, const val_t *v, 3778 const type_t *tp, op_t op) 3779 { 3780 if (nsz > osz && 3781 (nv->u.integer & bit((unsigned int)(osz - 1))) != 0 && 3782 (nv->u.integer & xmask) != xmask) { 3783 /* extra bits set to 0 in conversion of '%s' to '%s', ... */ 3784 warning(309, type_name(gettyp(ot)), 3785 type_name(tp), op_name(op)); 3786 } else if (nsz < osz && 3787 (v->u.integer & xmask) != xmask && 3788 (v->u.integer & xmask) != 0) 3789 /* constant truncated by conversion, op '%s' */ 3790 warning(306, op_name(op)); 3791 } 3792 3793 static void 3794 convert_constant_check_range_signed(op_t op, int arg) 3795 { 3796 if (op == ASSIGN) 3797 /* assignment of negative constant to unsigned type */ 3798 warning(164); 3799 else if (op == INIT) 3800 /* initialization of unsigned with negative constant */ 3801 warning(221); 3802 else if (op == FARG) 3803 /* conversion of negative constant to unsigned type, ... */ 3804 warning(296, arg); 3805 else if (modtab[op].m_comparison) { 3806 /* handled by check_integer_comparison() */ 3807 } else 3808 /* conversion of negative constant to unsigned type */ 3809 warning(222); 3810 } 3811 3812 /* 3813 * Loss of significant bit(s). All truncated bits of unsigned types or all 3814 * truncated bits plus the msb of the target for signed types are considered 3815 * to be significant bits. Loss of significant bits means that at least one 3816 * of the bits was set in an unsigned type or that at least one but not all 3817 * of the bits was set in a signed type. Loss of significant bits means that 3818 * it is not possible, also not with necessary casts, to convert back to the 3819 * original type. An example for a necessary cast is: 3820 * char c; int i; c = 128; 3821 * i = c; ** yields -128 ** 3822 * i = (unsigned char)c; ** yields 128 ** 3823 */ 3824 static void 3825 warn_constant_check_range_truncated(op_t op, int arg, const type_t *tp, 3826 tspec_t ot) 3827 { 3828 if (op == ASSIGN && tp->t_bitfield) 3829 /* precision lost in bit-field assignment */ 3830 warning(166); 3831 else if (op == ASSIGN) 3832 /* constant truncated by assignment */ 3833 warning(165); 3834 else if (op == INIT && tp->t_bitfield) 3835 /* bit-field initializer does not fit */ 3836 warning(180); 3837 else if (op == INIT) 3838 /* initializer does not fit */ 3839 warning(178); 3840 else if (op == CASE) 3841 /* case label affected by conversion */ 3842 warning(196); 3843 else if (op == FARG) 3844 /* conversion of '%s' to '%s' is out of range, arg #%d */ 3845 warning(295, type_name(gettyp(ot)), type_name(tp), arg); 3846 else 3847 /* conversion of '%s' to '%s' is out of range */ 3848 warning(119, type_name(gettyp(ot)), type_name(tp)); 3849 } 3850 3851 static void 3852 warn_constant_check_range_loss(op_t op, int arg, const type_t *tp, 3853 tspec_t ot) 3854 { 3855 if (op == ASSIGN && tp->t_bitfield) 3856 /* precision lost in bit-field assignment */ 3857 warning(166); 3858 else if (op == INIT && tp->t_bitfield) 3859 /* bit-field initializer out of range */ 3860 warning(11); 3861 else if (op == CASE) 3862 /* case label affected by conversion */ 3863 warning(196); 3864 else if (op == FARG) 3865 /* conversion of '%s' to '%s' is out of range, arg #%d */ 3866 warning(295, type_name(gettyp(ot)), type_name(tp), arg); 3867 else 3868 /* conversion of '%s' to '%s' is out of range */ 3869 warning(119, type_name(gettyp(ot)), type_name(tp)); 3870 } 3871 3872 static void 3873 convert_constant_check_range(tspec_t ot, const type_t *tp, tspec_t nt, 3874 op_t op, int arg, const val_t *v, val_t *nv) 3875 { 3876 unsigned int obitsz, nbitsz; 3877 uint64_t xmask, xmsk1; 3878 3879 obitsz = size_in_bits(ot); 3880 nbitsz = tp->t_bitfield ? tp->t_bit_field_width : size_in_bits(nt); 3881 xmask = value_bits(nbitsz) ^ value_bits(obitsz); 3882 xmsk1 = value_bits(nbitsz) ^ value_bits(obitsz - 1); 3883 if (op == ORASS || op == BITOR || op == BITXOR) { 3884 convert_constant_check_range_bitor( 3885 nbitsz, obitsz, v, xmask, op); 3886 } else if (op == ANDASS || op == BITAND) { 3887 convert_constant_check_range_bitand( 3888 nbitsz, obitsz, xmask, nv, ot, v, tp, op); 3889 } else if (nt != PTR && is_uinteger(nt) && 3890 ot != PTR && !is_uinteger(ot) && 3891 v->u.integer < 0) 3892 convert_constant_check_range_signed(op, arg); 3893 else if (nv->u.integer != v->u.integer && nbitsz <= obitsz && 3894 (v->u.integer & xmask) != 0 && 3895 (is_uinteger(ot) || (v->u.integer & xmsk1) != xmsk1)) 3896 warn_constant_check_range_truncated(op, arg, tp, ot); 3897 else if (nv->u.integer != v->u.integer) 3898 warn_constant_check_range_loss(op, arg, tp, ot); 3899 } 3900 3901 /* Converts a typed constant to a constant of another type. */ 3902 void 3903 convert_constant(op_t op, int arg, const type_t *ntp, val_t *nv, val_t *ov) 3904 { 3905 /* 3906 * TODO: make 'ov' const; the name of this function does not suggest 3907 * that it modifies 'ov'. 3908 */ 3909 tspec_t ot = ov->v_tspec; 3910 tspec_t nt = nv->v_tspec = ntp->t_tspec; 3911 bool range_check = false; 3912 3913 if (nt == BOOL) { /* C99 6.3.1.2 */ 3914 nv->v_unsigned_since_c90 = false; 3915 nv->u.integer = is_nonzero_val(ov) ? 1 : 0; 3916 return; 3917 } 3918 3919 if (ot == FLOAT || ot == DOUBLE || ot == LDOUBLE) 3920 convert_constant_floating(op, arg, ot, ntp, nt, ov, nv); 3921 else if (!convert_constant_to_floating(nt, nv, ot, ov)) { 3922 range_check = true; /* Check for lost precision. */ 3923 nv->u.integer = ov->u.integer; 3924 } 3925 3926 if (allow_trad && allow_c90 && ov->v_unsigned_since_c90 && 3927 (is_floating(nt) || ( 3928 (is_integer(nt) && !is_uinteger(nt) && 3929 portable_rank_cmp(nt, ot) > 0)))) { 3930 /* C90 treats constant as unsigned */ 3931 warning(157); 3932 ov->v_unsigned_since_c90 = false; 3933 } 3934 3935 if (is_integer(nt)) { 3936 unsigned int size = ntp->t_bitfield 3937 ? ntp->t_bit_field_width : size_in_bits(nt); 3938 nv->u.integer = convert_integer(nv->u.integer, nt, size); 3939 } 3940 3941 if (range_check && op != CVT) 3942 convert_constant_check_range(ot, ntp, nt, op, arg, ov, nv); 3943 } 3944 3945 tnode_t * 3946 build_sizeof(const type_t *tp) 3947 { 3948 unsigned int size_in_bytes = type_size_in_bits(tp) / CHAR_SIZE; 3949 tnode_t *tn = build_integer_constant(SIZEOF_TSPEC, size_in_bytes); 3950 tn->tn_system_dependent = true; 3951 debug_step("build_sizeof '%s' = %u", type_name(tp), size_in_bytes); 3952 return tn; 3953 } 3954 3955 tnode_t * 3956 build_offsetof(const type_t *tp, designation dn) 3957 { 3958 unsigned int offset_in_bits = 0; 3959 3960 if (!is_struct_or_union(tp->t_tspec)) { 3961 /* unacceptable operand of '%s' */ 3962 error(111, "offsetof"); 3963 goto proceed; 3964 } 3965 for (size_t i = 0; i < dn.dn_len; i++) { 3966 const designator *dr = dn.dn_items + i; 3967 if (dr->dr_kind == DK_SUBSCRIPT) { 3968 if (tp->t_tspec != ARRAY) 3969 goto proceed; /* silent error */ 3970 tp = tp->t_subt; 3971 offset_in_bits += (unsigned) dr->dr_subscript 3972 * type_size_in_bits(tp); 3973 } else { 3974 if (!is_struct_or_union(tp->t_tspec)) 3975 goto proceed; /* silent error */ 3976 const char *name = dr->dr_member->s_name; 3977 sym_t *mem = find_member(tp->u.sou, name); 3978 if (mem == NULL) { 3979 /* type '%s' does not have member '%s' */ 3980 error(101, name, type_name(tp)); 3981 goto proceed; 3982 } 3983 tp = mem->s_type; 3984 offset_in_bits += mem->u.s_member.sm_offset_in_bits; 3985 } 3986 } 3987 free(dn.dn_items); 3988 3989 proceed:; 3990 unsigned int offset_in_bytes = offset_in_bits / CHAR_SIZE; 3991 tnode_t *tn = build_integer_constant(SIZEOF_TSPEC, offset_in_bytes); 3992 tn->tn_system_dependent = true; 3993 return tn; 3994 } 3995 3996 unsigned int 3997 type_size_in_bits(const type_t *tp) 3998 { 3999 4000 unsigned int elem = 1; 4001 bool flex = false; 4002 lint_assert(tp != NULL); 4003 while (tp->t_tspec == ARRAY) { 4004 flex = true; /* allow c99 flex arrays [] [0] */ 4005 elem *= tp->u.dimension; 4006 tp = tp->t_subt; 4007 } 4008 if (elem == 0 && !flex) { 4009 /* cannot take size/alignment of incomplete type */ 4010 error(143); 4011 elem = 1; 4012 } 4013 4014 unsigned int elsz; 4015 switch (tp->t_tspec) { 4016 case VOID: 4017 /* cannot take size/alignment of void */ 4018 error(146); 4019 elsz = 1; 4020 break; 4021 case FUNC: 4022 /* cannot take size/alignment of function type '%s' */ 4023 error(144, type_name(tp)); 4024 elsz = 1; 4025 break; 4026 case STRUCT: 4027 case UNION: 4028 if (is_incomplete(tp)) { 4029 /* cannot take size/alignment of incomplete type */ 4030 error(143); 4031 elsz = 1; 4032 } else 4033 elsz = tp->u.sou->sou_size_in_bits; 4034 break; 4035 case ENUM: 4036 if (is_incomplete(tp)) { 4037 /* cannot take size/alignment of incomplete type */ 4038 warning(143); 4039 } 4040 /* FALLTHROUGH */ 4041 default: 4042 if (tp->t_bitfield) 4043 /* cannot take size/alignment of bit-field */ 4044 error(145); 4045 elsz = size_in_bits(tp->t_tspec); 4046 lint_assert(elsz > 0); 4047 break; 4048 } 4049 4050 return elem * elsz; 4051 } 4052 4053 /* C11 6.5.3.4, GCC */ 4054 tnode_t * 4055 build_alignof(const type_t *tp) 4056 { 4057 if (tp->t_tspec == FUNC) { 4058 /* cannot take size/alignment of function type '%s' */ 4059 error(144, type_name(tp)); 4060 return NULL; 4061 } 4062 if (tp->t_tspec == VOID) { 4063 /* cannot take size/alignment of void */ 4064 error(146); 4065 return NULL; 4066 } 4067 if (is_incomplete(tp)) { 4068 /* cannot take size/alignment of incomplete type */ 4069 error(143); 4070 return NULL; 4071 } 4072 if (tp->t_bitfield) { 4073 /* cannot take size/alignment of bit-field */ 4074 error(145); 4075 return NULL; 4076 } 4077 return build_integer_constant(SIZEOF_TSPEC, 4078 (int64_t)alignment_in_bits(tp) / CHAR_SIZE); 4079 } 4080 4081 static tnode_t * 4082 cast_to_union(tnode_t *otn, bool sys, type_t *ntp) 4083 { 4084 4085 if (!allow_gcc) { 4086 /* union cast is a GCC extension */ 4087 error(328); 4088 return NULL; 4089 } 4090 4091 for (const sym_t *m = ntp->u.sou->sou_first_member; 4092 m != NULL; m = m->s_next) { 4093 if (types_compatible(m->s_type, otn->tn_type, 4094 false, false, NULL)) { 4095 tnode_t *ntn = build_op(CVT, sys, ntp, otn, NULL); 4096 ntn->tn_cast = true; 4097 return ntn; 4098 } 4099 } 4100 4101 /* type '%s' is not a member of '%s' */ 4102 error(329, type_name(otn->tn_type), type_name(ntp)); 4103 return NULL; 4104 } 4105 4106 tnode_t * 4107 cast(tnode_t *tn, bool sys, type_t *tp) 4108 { 4109 4110 if (tn == NULL) 4111 return NULL; 4112 4113 tn = cconv(tn); 4114 4115 lint_assert(tp != NULL); 4116 tspec_t nt = tp->t_tspec; 4117 tspec_t ot = tn->tn_type->t_tspec; 4118 4119 if (nt == VOID) { 4120 /* 4121 * C90 6.3.4, C99 6.5.4p2 and C11 6.5.4p2 allow any type to be 4122 * cast to void. The only other allowed casts are from a 4123 * scalar type to a scalar type. 4124 */ 4125 } else if (nt == UNION) 4126 return cast_to_union(tn, sys, tp); 4127 else if (nt == STRUCT || nt == ARRAY || nt == FUNC) { 4128 /* Casting to a struct is an undocumented GCC extension. */ 4129 if (!(allow_gcc && nt == STRUCT)) 4130 goto invalid_cast; 4131 } else if (is_struct_or_union(ot)) 4132 goto invalid_cast; 4133 else if (ot == VOID) { 4134 /* improper cast of void expression */ 4135 error(148); 4136 return NULL; 4137 } else if (is_integer(nt) && is_scalar(ot)) { 4138 /* ok */ 4139 } else if (is_floating(nt) && is_arithmetic(ot)) { 4140 /* ok */ 4141 } else if (nt == PTR && is_integer(ot)) { 4142 /* ok */ 4143 } else if (nt == PTR && ot == PTR) { 4144 if (!tp->t_subt->t_const && tn->tn_type->t_subt->t_const) { 4145 if (hflag) 4146 /* cast discards 'const' from type '%s' */ 4147 warning(275, type_name(tn->tn_type)); 4148 } 4149 } else 4150 goto invalid_cast; 4151 4152 if (any_query_enabled 4153 && types_compatible(tp, tn->tn_type, false, false, NULL)) 4154 /* no-op cast from '%s' to '%s' */ 4155 query_message(6, type_name(tn->tn_type), type_name(tp)); 4156 4157 tn = convert(CVT, 0, tp, tn); 4158 tn->tn_cast = true; 4159 tn->tn_sys = sys; 4160 4161 return tn; 4162 4163 invalid_cast: 4164 /* invalid cast from '%s' to '%s' */ 4165 error(147, type_name(tn->tn_type), type_name(tp)); 4166 return NULL; 4167 } 4168 4169 void 4170 add_function_argument(function_call *call, tnode_t *arg) 4171 { 4172 /* 4173 * If there was a serious error in the expression for the argument, 4174 * create a dummy argument so the positions of the remaining arguments 4175 * will not change. 4176 */ 4177 if (arg == NULL) 4178 arg = build_integer_constant(INT, 0); 4179 4180 if (call->args_len >= call->args_cap) { 4181 call->args_cap += 8; 4182 tnode_t **new_args = expr_zero_alloc( 4183 call->args_cap * sizeof(*call->args), 4184 "function_call.args"); 4185 memcpy(new_args, call->args, 4186 call->args_len * sizeof(*call->args)); 4187 call->args = new_args; 4188 } 4189 call->args[call->args_len++] = arg; 4190 } 4191 4192 /* 4193 * Compare the type of an argument with the corresponding type of a 4194 * prototype parameter. If it is a valid combination, but both types 4195 * are not the same, insert a conversion to convert the argument into 4196 * the type of the parameter. 4197 */ 4198 static tnode_t * 4199 check_prototype_argument( 4200 int n, /* pos of arg */ 4201 type_t *tp, /* expected type (from prototype) */ 4202 tnode_t *tn) /* argument */ 4203 { 4204 tnode_t *ln = xcalloc(1, sizeof(*ln)); 4205 ln->tn_type = expr_unqualified_type(tp); 4206 ln->tn_lvalue = true; 4207 if (typeok(FARG, n, ln, tn)) { 4208 bool dowarn; 4209 if (!types_compatible(tp, tn->tn_type, 4210 true, false, (dowarn = false, &dowarn)) || dowarn) 4211 tn = convert(FARG, n, tp, tn); 4212 } 4213 free(ln); 4214 return tn; 4215 } 4216 4217 /* 4218 * Check types of all function arguments and insert conversions, 4219 * if necessary. 4220 */ 4221 static void 4222 check_function_arguments(const function_call *call) 4223 { 4224 type_t *ftp = call->func->tn_type->t_subt; 4225 4226 /* get # of parameters in the prototype */ 4227 int npar = 0; 4228 for (const sym_t *p = ftp->u.params; p != NULL; p = p->s_next) 4229 npar++; 4230 4231 int narg = (int)call->args_len; 4232 4233 const sym_t *param = ftp->u.params; 4234 if (ftp->t_proto && npar != narg && !(ftp->t_vararg && npar < narg)) { 4235 /* argument mismatch: %d %s passed, %d expected */ 4236 error(150, narg, narg != 1 ? "arguments" : "argument", npar); 4237 param = NULL; 4238 } 4239 4240 for (int i = 0; i < narg; i++) { 4241 tnode_t *arg = call->args[i]; 4242 4243 /* some things which are always not allowed */ 4244 tspec_t at = arg->tn_type->t_tspec; 4245 if (at == VOID) { 4246 /* void expressions may not be arguments, arg #%d */ 4247 error(151, i + 1); 4248 return; 4249 } 4250 if (is_struct_or_union(at) && is_incomplete(arg->tn_type)) { 4251 /* argument cannot have unknown size, arg #%d */ 4252 error(152, i + 1); 4253 return; 4254 } 4255 if (is_integer(at) && 4256 arg->tn_type->t_is_enum && 4257 is_incomplete(arg->tn_type)) { 4258 /* argument cannot have unknown size, arg #%d */ 4259 warning(152, i + 1); 4260 } 4261 4262 arg = cconv(arg); 4263 call->args[i] = arg; 4264 4265 arg = param != NULL 4266 ? check_prototype_argument(i + 1, param->s_type, arg) 4267 : promote(NOOP, true, arg); 4268 call->args[i] = arg; 4269 4270 if (param != NULL) 4271 param = param->s_next; 4272 } 4273 } 4274 4275 tnode_t * 4276 build_function_call(tnode_t *func, bool sys, function_call *call) 4277 { 4278 4279 if (func == NULL) 4280 return NULL; 4281 4282 call->func = func; 4283 check_ctype_function_call(call); 4284 4285 func = cconv(func); 4286 call->func = func; 4287 4288 if (func->tn_type->t_tspec != PTR || 4289 func->tn_type->t_subt->t_tspec != FUNC) { 4290 /* cannot call '%s', must be a function */ 4291 error(149, type_name(func->tn_type)); 4292 return NULL; 4293 } 4294 4295 check_function_arguments(call); 4296 4297 tnode_t *ntn = expr_alloc_tnode(); 4298 ntn->tn_op = CALL; 4299 ntn->tn_type = func->tn_type->t_subt->t_subt; 4300 ntn->tn_sys = sys; 4301 ntn->u.call = call; 4302 return ntn; 4303 } 4304 4305 /* 4306 * Return the value of an integral constant expression. 4307 * If the expression is not constant or its type is not an integer 4308 * type, an error message is printed. 4309 */ 4310 val_t * 4311 integer_constant(tnode_t *tn, bool required) 4312 { 4313 4314 if (tn != NULL) 4315 tn = cconv(tn); 4316 if (tn != NULL) 4317 tn = promote(NOOP, false, tn); 4318 4319 val_t *v = xcalloc(1, sizeof(*v)); 4320 4321 if (tn == NULL) { 4322 lint_assert(seen_error); 4323 debug_step("constant node is null; returning 1 instead"); 4324 v->v_tspec = INT; 4325 v->u.integer = 1; 4326 return v; 4327 } 4328 4329 v->v_tspec = tn->tn_type->t_tspec; 4330 4331 if (tn->tn_op == CON) { 4332 lint_assert(tn->tn_type->t_tspec == tn->u.value.v_tspec); 4333 if (is_integer(tn->u.value.v_tspec)) { 4334 v->v_unsigned_since_c90 = 4335 tn->u.value.v_unsigned_since_c90; 4336 v->u.integer = tn->u.value.u.integer; 4337 return v; 4338 } 4339 v->u.integer = (int64_t)tn->u.value.u.floating; 4340 } else 4341 v->u.integer = 1; 4342 4343 if (required) 4344 /* integral constant expression expected */ 4345 error(55); 4346 else 4347 /* variable array dimension is a C99/GCC extension */ 4348 c99ism(318); 4349 4350 if (!is_integer(v->v_tspec)) 4351 v->v_tspec = INT; 4352 4353 return v; 4354 } 4355 4356 static bool 4357 is_constcond_false(const tnode_t *tn, tspec_t t) 4358 { 4359 return (t == BOOL || t == INT) && 4360 tn->tn_op == CON && tn->u.value.u.integer == 0; 4361 } 4362 4363 /* 4364 * Perform some tests on expressions which can't be done in build_binary() 4365 * and functions called by build_binary(). These tests must be done here 4366 * because we need some information about the context in which the operations 4367 * are performed. 4368 * After all tests are performed and dofreeblk is true, expr() frees the 4369 * memory which is used for the expression. 4370 */ 4371 void 4372 expr(tnode_t *tn, bool vctx, bool cond, bool dofreeblk, bool is_do_while) 4373 { 4374 4375 if (tn == NULL) { /* in case of errors */ 4376 expr_free_all(); 4377 return; 4378 } 4379 4380 /* expr() is also called in global initializations */ 4381 if (dcs->d_kind != DLK_EXTERN && !is_do_while) 4382 check_statement_reachable(); 4383 4384 check_expr_misc(tn, vctx, cond, !cond, false, false, false); 4385 if (tn->tn_op == ASSIGN && !tn->tn_parenthesized) { 4386 if (hflag && cond) 4387 /* assignment in conditional context */ 4388 warning(159); 4389 } else if (tn->tn_op == CON) { 4390 if (hflag && cond && !suppress_constcond && 4391 !tn->tn_system_dependent && 4392 !(is_do_while && 4393 is_constcond_false(tn, tn->tn_type->t_tspec))) 4394 /* constant in conditional context */ 4395 warning(161); 4396 } 4397 if (!modtab[tn->tn_op].m_has_side_effect) { 4398 /* 4399 * for left operands of COMMA this warning is already printed 4400 */ 4401 if (tn->tn_op != COMMA && !vctx && !cond) 4402 check_null_effect(tn); 4403 } 4404 debug_node(tn); 4405 4406 if (dofreeblk) 4407 expr_free_all(); 4408 } 4409 4410 /* If the expression has the form '*(arr + idx)', check the array index. */ 4411 static void 4412 check_array_index(const tnode_t *indir, bool taking_address) 4413 { 4414 const tnode_t *plus, *arr, *idx; 4415 4416 if (indir->tn_op == INDIR 4417 && (plus = indir->u.ops.left, plus->tn_op == PLUS) 4418 && plus->u.ops.left->tn_op == ADDR 4419 && (arr = plus->u.ops.left->u.ops.left, true) 4420 && (arr->tn_op == STRING || arr->tn_op == NAME) 4421 && arr->tn_type->t_tspec == ARRAY 4422 && (idx = plus->u.ops.right, idx->tn_op == CON) 4423 && (!is_incomplete(arr->tn_type) || idx->u.value.u.integer < 0)) 4424 goto proceed; 4425 return; 4426 4427 proceed:; 4428 int elsz = length_in_bits(arr->tn_type->t_subt, NULL); 4429 if (elsz == 0) 4430 return; 4431 elsz /= CHAR_SIZE; 4432 4433 /* Change the unit of the index from bytes to element size. */ 4434 int64_t con = is_uinteger(idx->tn_type->t_tspec) 4435 ? (int64_t)((uint64_t)idx->u.value.u.integer / elsz) 4436 : idx->u.value.u.integer / elsz; 4437 4438 int dim = arr->tn_type->u.dimension + (taking_address ? 1 : 0); 4439 4440 if (!is_uinteger(idx->tn_type->t_tspec) && con < 0) 4441 /* array subscript %jd cannot be negative */ 4442 warning(167, (intmax_t)con); 4443 else if (dim > 0 && (uint64_t)con >= (uint64_t)dim) 4444 /* array subscript %ju cannot be > %d */ 4445 warning(168, (uintmax_t)con, dim - 1); 4446 } 4447 4448 static void 4449 check_expr_addr(const tnode_t *ln, bool szof, bool fcall) 4450 { 4451 /* XXX: Taking warn_about_unreachable into account here feels wrong. */ 4452 if (ln->tn_op == NAME && (reached || !warn_about_unreachable)) { 4453 if (!szof) 4454 mark_as_set(ln->u.sym); 4455 mark_as_used(ln->u.sym, fcall, szof); 4456 } 4457 check_array_index(ln, true); 4458 } 4459 4460 /* 4461 * If there is an asm statement in one of the compound statements around, 4462 * there may be other side effects, so don't warn. 4463 */ 4464 static bool 4465 is_asm_around(void) 4466 { 4467 for (decl_level *dl = dcs; dl != NULL; dl = dl->d_enclosing) 4468 if (dl->d_asm) 4469 return true; 4470 return false; 4471 } 4472 4473 static void 4474 check_expr_side_effect(const tnode_t *ln, bool szof) 4475 { 4476 4477 /* XXX: Taking warn_about_unreachable into account here feels wrong. */ 4478 if (ln->tn_op == NAME && (reached || !warn_about_unreachable)) { 4479 scl_t sc = ln->u.sym->s_scl; 4480 if (sc != EXTERN && sc != STATIC && 4481 !ln->u.sym->s_set && !szof && !is_asm_around()) { 4482 /* '%s' may be used before set */ 4483 warning(158, ln->u.sym->s_name); 4484 mark_as_set(ln->u.sym); 4485 } 4486 mark_as_used(ln->u.sym, false, false); 4487 } 4488 } 4489 4490 static void 4491 check_expr_assign(const tnode_t *ln, bool szof) 4492 { 4493 /* XXX: Taking warn_about_unreachable into account here feels wrong. */ 4494 if (ln->tn_op == NAME && !szof && (reached || !warn_about_unreachable)) { 4495 mark_as_set(ln->u.sym); 4496 if (ln->u.sym->s_scl == EXTERN) 4497 outusg(ln->u.sym); 4498 } 4499 check_array_index(ln, false); 4500 } 4501 4502 static void 4503 check_expr_call(const tnode_t *tn, const tnode_t *ln, 4504 bool szof, bool vctx, bool cond, bool retval_discarded) 4505 { 4506 lint_assert(ln->tn_op == ADDR); 4507 lint_assert(ln->u.ops.left->tn_op == NAME); 4508 if (!szof && !is_compiler_builtin(ln->u.ops.left->u.sym->s_name)) 4509 outcall(tn, vctx || cond, retval_discarded); 4510 4511 const function_call *call = tn->u.call; 4512 if (call->args_len == 4 || call->args_len == 5) 4513 check_snprintb(call); 4514 } 4515 4516 static void 4517 check_expr_op(op_t op, const tnode_t *ln, bool szof, bool fcall, bool eqwarn) 4518 { 4519 switch (op) { 4520 case ADDR: 4521 check_expr_addr(ln, szof, fcall); 4522 break; 4523 case LOAD: 4524 check_array_index(ln, false); 4525 /* FALLTHROUGH */ 4526 case INCBEF: 4527 case DECBEF: 4528 case INCAFT: 4529 case DECAFT: 4530 case ADDASS: 4531 case SUBASS: 4532 case MULASS: 4533 case DIVASS: 4534 case MODASS: 4535 case ANDASS: 4536 case ORASS: 4537 case XORASS: 4538 case SHLASS: 4539 case SHRASS: 4540 case REAL: 4541 case IMAG: 4542 check_expr_side_effect(ln, szof); 4543 break; 4544 case ASSIGN: 4545 check_expr_assign(ln, szof); 4546 break; 4547 case EQ: 4548 if (hflag && eqwarn) 4549 /* operator '==' found where '=' was expected */ 4550 warning(160); 4551 break; 4552 default: 4553 break; 4554 } 4555 } 4556 4557 /* 4558 * vctx ??? 4559 * cond whether the expression is a condition that 4560 * will be compared with 0 4561 * eqwarn whether the operator '==' might be a 4562 * misspelled '=' 4563 * fcall whether the expression is a function call 4564 * retval_discarded whether the return value of a function call 4565 * is discarded; such calls will be analyzed by 4566 * lint2 in messages 4, 8 and 9 4567 * szof whether the expression is part of a sizeof 4568 * expression, which means that its value is 4569 * discarded since only the type is relevant 4570 */ 4571 void 4572 check_expr_misc(const tnode_t *tn, bool vctx, bool cond, 4573 bool eqwarn, bool fcall, bool retval_discarded, bool szof) 4574 { 4575 4576 if (tn == NULL) 4577 return; 4578 op_t op = tn->tn_op; 4579 if (op == NAME || op == CON || op == STRING) 4580 return; 4581 bool is_direct = op == CALL 4582 && tn->u.call->func->tn_op == ADDR 4583 && tn->u.call->func->u.ops.left->tn_op == NAME; 4584 if (op == CALL) { 4585 const function_call *call = tn->u.call; 4586 if (is_direct) 4587 check_expr_call(tn, call->func, 4588 szof, vctx, cond, retval_discarded); 4589 bool discard = op == CVT && tn->tn_type->t_tspec == VOID; 4590 check_expr_misc(call->func, false, false, false, is_direct, 4591 discard, szof); 4592 for (size_t i = 0, n = call->args_len; i < n; i++) 4593 check_expr_misc(call->args[i], 4594 false, false, false, false, false, szof); 4595 return; 4596 } 4597 4598 lint_assert(has_operands(tn)); 4599 tnode_t *ln = tn->u.ops.left; 4600 tnode_t *rn = tn->u.ops.right; 4601 check_expr_op(op, ln, szof, fcall, eqwarn); 4602 4603 const mod_t *mp = &modtab[op]; 4604 bool cvctx = mp->m_value_context; 4605 bool ccond = mp->m_compares_with_zero; 4606 bool eq = mp->m_warn_if_operand_eq && 4607 !ln->tn_parenthesized && 4608 rn != NULL && !rn->tn_parenthesized; 4609 4610 /* 4611 * Values of operands of ':' are not used if the type of at least 4612 * one of the operands (for GCC compatibility) is 'void'. 4613 * 4614 * XXX test/value context of QUEST should probably be used as 4615 * context for both operands of COLON. 4616 */ 4617 if (op == COLON && tn->tn_type->t_tspec == VOID) 4618 cvctx = ccond = false; 4619 bool discard = op == CVT && tn->tn_type->t_tspec == VOID; 4620 check_expr_misc(ln, cvctx, ccond, eq, is_direct, discard, szof); 4621 4622 switch (op) { 4623 case LOGAND: 4624 case LOGOR: 4625 check_expr_misc(rn, false, true, eq, false, false, szof); 4626 break; 4627 case COLON: 4628 check_expr_misc(rn, cvctx, ccond, eq, false, false, szof); 4629 break; 4630 case COMMA: 4631 check_expr_misc(rn, vctx, cond, false, false, false, szof); 4632 break; 4633 default: 4634 if (mp->m_binary) 4635 check_expr_misc(rn, true, false, eq, false, false, 4636 szof); 4637 break; 4638 } 4639 } 4640 4641 /* 4642 * Return whether the expression can be used for static initialization. 4643 * 4644 * Constant initialization expressions must be constant or an address 4645 * of a static object with an optional offset. In the first case, 4646 * the result is returned in *offsp. In the second case, the static 4647 * object is returned in *symp and the offset in *offsp. 4648 * 4649 * The expression can consist of PLUS, MINUS, ADDR, NAME, STRING and 4650 * CON. Type conversions are allowed if they do not change binary 4651 * representation (including width). 4652 * 4653 * C99 6.6 "Constant expressions" 4654 * C99 6.7.8p4 restricts initializers for static storage duration 4655 */ 4656 bool 4657 constant_addr(const tnode_t *tn, const sym_t **symp, ptrdiff_t *offsp) 4658 { 4659 const sym_t *sym; 4660 ptrdiff_t offs1, offs2; 4661 tspec_t t, ot; 4662 4663 switch (tn->tn_op) { 4664 case MINUS: 4665 if (tn->u.ops.right->tn_op == CVT) 4666 return constant_addr(tn->u.ops.right, symp, offsp); 4667 else if (tn->u.ops.right->tn_op != CON) 4668 return false; 4669 /* FALLTHROUGH */ 4670 case PLUS: 4671 offs1 = offs2 = 0; 4672 if (tn->u.ops.left->tn_op == CON) { 4673 offs1 = (ptrdiff_t)tn->u.ops.left->u.value.u.integer; 4674 if (!constant_addr(tn->u.ops.right, &sym, &offs2)) 4675 return false; 4676 } else if (tn->u.ops.right->tn_op == CON) { 4677 offs2 = (ptrdiff_t)tn->u.ops.right->u.value.u.integer; 4678 if (tn->tn_op == MINUS) 4679 offs2 = -offs2; 4680 if (!constant_addr(tn->u.ops.left, &sym, &offs1)) 4681 return false; 4682 } else { 4683 return false; 4684 } 4685 *symp = sym; 4686 *offsp = offs1 + offs2; 4687 return true; 4688 case ADDR: 4689 if (tn->u.ops.left->tn_op == NAME) { 4690 *symp = tn->u.ops.left->u.sym; 4691 *offsp = 0; 4692 return true; 4693 } else { 4694 /* 4695 * If this were the front end of a compiler, we would 4696 * return a label instead of 0, at least if 4697 * 'tn->u.ops.left->tn_op == STRING'. 4698 */ 4699 *symp = NULL; 4700 *offsp = 0; 4701 return true; 4702 } 4703 case CVT: 4704 t = tn->tn_type->t_tspec; 4705 ot = tn->u.ops.left->tn_type->t_tspec; 4706 if ((!is_integer(t) && t != PTR) || 4707 (!is_integer(ot) && ot != PTR)) { 4708 return false; 4709 } 4710 #if 0 4711 /*- 4712 * consider: 4713 * struct foo { 4714 * unsigned char a; 4715 * } f = { 4716 * (unsigned char)(unsigned long) 4717 * (&(((struct foo *)0)->a)) 4718 * }; 4719 * since psize(unsigned long) != psize(unsigned char), 4720 * this fails. 4721 */ 4722 else if (psize(t) != psize(ot)) 4723 return -1; 4724 #endif 4725 return constant_addr(tn->u.ops.left, symp, offsp); 4726 default: 4727 return false; 4728 } 4729 } 4730 4731 /* Append s2 to s1, then free s2. */ 4732 buffer * 4733 cat_strings(buffer *s1, buffer *s2) 4734 { 4735 4736 if ((s1->data != NULL) != (s2->data != NULL)) { 4737 /* cannot concatenate wide and regular string literals */ 4738 error(292); 4739 return s1; 4740 } 4741 4742 if (s1->data != NULL) { 4743 while (s1->len + s2->len + 1 > s1->cap) 4744 s1->cap *= 2; 4745 s1->data = xrealloc(s1->data, s1->cap); 4746 memcpy(s1->data + s1->len, s2->data, s2->len + 1); 4747 free(s2->data); 4748 } 4749 s1->len += s2->len; 4750 free(s2); 4751 4752 return s1; 4753 } 4754 4755 4756 typedef struct stmt_expr { 4757 memory_pool se_mem; 4758 sym_t *se_sym; 4759 struct stmt_expr *se_enclosing; 4760 } stmt_expr; 4761 4762 static stmt_expr *stmt_exprs; 4763 4764 void 4765 begin_statement_expr(void) 4766 { 4767 debug_enter(); 4768 4769 stmt_expr *se = xmalloc(sizeof(*se)); 4770 se->se_mem = expr_save_memory(); 4771 se->se_sym = NULL; 4772 se->se_enclosing = stmt_exprs; 4773 stmt_exprs = se; 4774 } 4775 4776 void 4777 do_statement_expr(tnode_t *tn) 4778 { 4779 block_level--; 4780 mem_block_level--; 4781 stmt_exprs->se_sym = tn != NULL 4782 ? mktempsym(block_dup_type(tn->tn_type)) 4783 : NULL; /* after a syntax error */ 4784 mem_block_level++; 4785 block_level++; 4786 /* '({ ... })' is a GCC extension */ 4787 gnuism(320); 4788 } 4789 4790 tnode_t * 4791 end_statement_expr(void) 4792 { 4793 tnode_t *tn; 4794 4795 stmt_expr *se = stmt_exprs; 4796 if (se->se_sym == NULL) { 4797 tn = NULL; /* after a syntax error */ 4798 goto end; 4799 } 4800 4801 tn = build_name(se->se_sym, false); 4802 (void)expr_save_memory(); /* leak */ 4803 expr_restore_memory(se->se_mem); 4804 stmt_exprs = se->se_enclosing; 4805 free(se); 4806 4807 end: 4808 debug_leave(); 4809 return tn; 4810 } 4811 4812 bool 4813 in_statement_expr(void) 4814 { 4815 return stmt_exprs != NULL; 4816 } 4817
Indexes created Mon Sep 22 10:09:38 GMT 2025