tree.c revision 1.601
1 /* $NetBSD: tree.c,v 1.601 2024/02/01 21:19:13 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 1.601 2024/02/01 21:19:13 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->tn_val); 286 case CVT: 287 if (!is_integer(tn->tn_left->tn_type->t_tspec)) 288 return ic_any(tn->tn_type); 289 lc = ic_expr(tn->tn_left); 290 return ic_cvt(tn->tn_type, tn->tn_left->tn_type, lc); 291 case MOD: 292 lc = ic_expr(before_conversion(tn->tn_left)); 293 rc = ic_expr(before_conversion(tn->tn_right)); 294 return ic_mod(tn->tn_type, lc, rc); 295 case SHL: 296 lc = ic_expr(tn->tn_left); 297 rc = ic_expr(tn->tn_right); 298 return ic_shl(tn->tn_type, lc, rc); 299 case SHR: 300 lc = ic_expr(tn->tn_left); 301 rc = ic_expr(tn->tn_right); 302 return ic_shr(tn->tn_type, lc, rc); 303 case BITAND: 304 lc = ic_expr(tn->tn_left); 305 rc = ic_expr(tn->tn_right); 306 return ic_bitand(lc, rc); 307 case BITOR: 308 lc = ic_expr(tn->tn_left); 309 rc = ic_expr(tn->tn_right); 310 return ic_bitor(lc, rc); 311 case QUEST: 312 lc = ic_expr(tn->tn_right->tn_left); 313 rc = ic_expr(tn->tn_right->tn_right); 314 return ic_cond(lc, rc); 315 default: 316 return ic_any(tn->tn_type); 317 } 318 } 319 320 /* Build 'pointer to tp', 'array of tp' or 'function returning tp'. */ 321 type_t * 322 block_derive_type(type_t *tp, tspec_t t) 323 { 324 type_t *tp2; 325 326 tp2 = block_zero_alloc(sizeof(*tp2), "type"); 327 tp2->t_tspec = t; 328 tp2->t_subt = tp; 329 return tp2; 330 } 331 332 /* 333 * Derive 'pointer to tp' or 'function returning tp'. 334 * The memory is freed at the end of the current expression. 335 */ 336 type_t * 337 expr_derive_type(type_t *tp, tspec_t t) 338 { 339 type_t *tp2; 340 341 tp2 = expr_zero_alloc(sizeof(*tp2), "type"); 342 tp2->t_tspec = t; 343 tp2->t_subt = tp; 344 return tp2; 345 } 346 347 /* Create an expression from a unary or binary operator and its operands. */ 348 static tnode_t * 349 build_op(op_t op, bool sys, type_t *type, tnode_t *ln, tnode_t *rn) 350 { 351 352 tnode_t *ntn = expr_alloc_tnode(); 353 ntn->tn_op = op; 354 ntn->tn_type = type; 355 ntn->tn_sys = sys; 356 ntn->tn_left = ln; 357 ntn->tn_right = rn; 358 359 if (op == INDIR || op == FSEL) { 360 lint_assert(ln->tn_type->t_tspec == PTR); 361 tspec_t t = ln->tn_type->t_subt->t_tspec; 362 ntn->tn_lvalue = t != FUNC && t != VOID; 363 } 364 365 return ntn; 366 } 367 368 tnode_t * 369 build_constant(type_t *tp, val_t *v) 370 { 371 372 tnode_t *n = expr_alloc_tnode(); 373 n->tn_op = CON; 374 n->tn_type = tp; 375 n->tn_val = *v; 376 n->tn_val.v_tspec = tp->t_tspec; 377 free(v); 378 return n; 379 } 380 381 static tnode_t * 382 build_integer_constant(tspec_t t, int64_t si) 383 { 384 385 tnode_t *n = expr_alloc_tnode(); 386 n->tn_op = CON; 387 n->tn_type = gettyp(t); 388 n->tn_val.v_tspec = t; 389 n->tn_val.v_unsigned_since_c90 = false; 390 n->tn_val.v_char_constant = false; 391 n->tn_val.u.integer = si; 392 return n; 393 } 394 395 static void 396 fallback_symbol(sym_t *sym) 397 { 398 399 if (Tflag && fallback_symbol_strict_bool(sym)) 400 return; 401 402 if (block_level > 0 && (strcmp(sym->s_name, "__FUNCTION__") == 0 || 403 strcmp(sym->s_name, "__PRETTY_FUNCTION__") == 0)) { 404 /* __FUNCTION__/__PRETTY_FUNCTION__ is a GCC extension */ 405 gnuism(316); 406 // XXX: Should probably be ARRAY instead of PTR. 407 sym->s_type = block_derive_type(gettyp(CHAR), PTR); 408 sym->s_type->t_const = true; 409 return; 410 } 411 412 if (funcsym != NULL && strcmp(sym->s_name, "__func__") == 0) { 413 if (!allow_c99) 414 /* __func__ is a C99 feature */ 415 warning(317); 416 /* C11 6.4.2.2 */ 417 sym->s_type = block_derive_type(gettyp(CHAR), ARRAY); 418 sym->s_type->t_const = true; 419 sym->s_type->t_dim = (int)strlen(funcsym->s_name) + 1; 420 return; 421 } 422 423 /* '%s' undefined */ 424 error(99, sym->s_name); 425 } 426 427 /* 428 * Functions that are predeclared by GCC or other compilers can be called 429 * with arbitrary arguments. Since lint usually runs after a successful 430 * compilation, it's the compiler's job to catch any errors. 431 */ 432 bool 433 is_compiler_builtin(const char *name) 434 { 435 /* https://gcc.gnu.org/onlinedocs/gcc/C-Extensions.html */ 436 if (allow_gcc) { 437 if (strncmp(name, "__atomic_", 9) == 0 || 438 strncmp(name, "__builtin_", 10) == 0 || 439 strcmp(name, "alloca") == 0 || 440 /* obsolete but still in use, as of 2021 */ 441 strncmp(name, "__sync_", 7) == 0) 442 return true; 443 } 444 445 /* https://software.intel.com/sites/landingpage/IntrinsicsGuide/ */ 446 if (strncmp(name, "_mm_", 4) == 0) 447 return true; 448 449 return false; 450 } 451 452 /* https://gcc.gnu.org/onlinedocs/gcc/Integer-Overflow-Builtins.html */ 453 static bool 454 is_gcc_bool_builtin(const char *name) 455 { 456 return strncmp(name, "__builtin_", 10) == 0 && 457 (str_ends_with(name, "_overflow") || 458 str_ends_with(name, "_overflow_p")); 459 } 460 461 static void 462 build_name_call(sym_t *sym) 463 { 464 465 if (is_compiler_builtin(sym->s_name)) { 466 /* 467 * Do not warn about these, just assume that they are regular 468 * functions compatible with non-prototype calling conventions. 469 */ 470 if (allow_gcc && is_gcc_bool_builtin(sym->s_name)) 471 sym->s_type = gettyp(BOOL); 472 } else if (allow_c99) { 473 /* function '%s' implicitly declared to return int */ 474 error(215, sym->s_name); 475 } else if (!allow_trad) { 476 /* function '%s' implicitly declared to return int */ 477 warning(215, sym->s_name); 478 } 479 480 /* XXX if !allow_c90, the symbol should be exported to level 0 */ 481 sym->s_type = block_derive_type(sym->s_type, FUNC); 482 } 483 484 /* Create a node for a name (symbol table entry). */ 485 tnode_t * 486 build_name(sym_t *sym, bool is_funcname) 487 { 488 489 if (sym->s_scl == NO_SCL && !in_gcc_attribute) { 490 sym->s_scl = EXTERN; 491 sym->s_def = DECL; 492 if (is_funcname) 493 build_name_call(sym); 494 else 495 fallback_symbol(sym); 496 } 497 498 lint_assert(sym->s_kind == SK_VCFT || sym->s_kind == SK_MEMBER); 499 500 tnode_t *n = expr_alloc_tnode(); 501 n->tn_type = sym->s_type; 502 if (sym->s_scl == BOOL_CONST) { 503 n->tn_op = CON; 504 n->tn_val.v_tspec = BOOL; 505 n->tn_val.v_unsigned_since_c90 = false; 506 n->tn_val.v_char_constant = false; 507 n->tn_val.u.integer = sym->u.s_bool_constant ? 1 : 0; 508 } else if (sym->s_scl == ENUM_CONST) { 509 n->tn_op = CON; 510 n->tn_val.v_tspec = INT; /* ENUM is in n->tn_type */ 511 n->tn_val.v_unsigned_since_c90 = false; 512 n->tn_val.v_char_constant = false; 513 n->tn_val.u.integer = sym->u.s_enum_constant; 514 } else { 515 n->tn_op = NAME; 516 n->tn_sym = sym; 517 if (sym->s_kind == SK_VCFT && sym->s_type->t_tspec != FUNC) 518 n->tn_lvalue = true; 519 } 520 521 return n; 522 } 523 524 tnode_t * 525 build_string(buffer *strg) 526 { 527 size_t len = strg->len; 528 529 type_t *tp = expr_zero_alloc(sizeof(*tp), "type"); 530 tp->t_tspec = ARRAY; 531 tp->t_subt = gettyp(strg->data != NULL ? CHAR : WCHAR_TSPEC); 532 tp->t_dim = (int)(len + 1); 533 534 tnode_t *n = expr_alloc_tnode(); 535 n->tn_op = STRING; 536 n->tn_type = tp; 537 n->tn_lvalue = true; 538 539 n->tn_string = expr_zero_alloc(sizeof(*n->tn_string), "tnode.string"); 540 n->tn_string->len = len; 541 542 if (strg->data != NULL) { 543 n->tn_string->data = expr_zero_alloc(len + 1, 544 "tnode.string.data"); 545 (void)memcpy(n->tn_string->data, strg->data, len + 1); 546 free(strg->data); 547 } 548 free(strg); 549 550 return n; 551 } 552 553 tnode_t * 554 build_generic_selection(const tnode_t *expr, 555 struct generic_association *sel) 556 { 557 tnode_t *default_result = NULL; 558 559 for (; sel != NULL; sel = sel->ga_prev) { 560 if (expr != NULL && 561 types_compatible(sel->ga_arg, expr->tn_type, 562 false, false, NULL)) 563 return sel->ga_result; 564 else if (sel->ga_arg == NULL) 565 default_result = sel->ga_result; 566 } 567 return default_result; 568 } 569 570 static bool 571 is_out_of_char_range(const tnode_t *tn) 572 { 573 return tn->tn_op == CON && 574 !tn->tn_val.v_char_constant && 575 !(0 <= tn->tn_val.u.integer && 576 tn->tn_val.u.integer < 1 << (CHAR_SIZE - 1)); 577 } 578 579 static bool 580 check_nonportable_char_comparison(op_t op, 581 const tnode_t *ln, tspec_t lt, 582 const tnode_t *rn, tspec_t rt) 583 { 584 if (!(hflag || pflag)) 585 return true; 586 587 if (lt == CHAR && is_out_of_char_range(rn)) { 588 char buf[128]; 589 (void)snprintf(buf, sizeof(buf), "%s %d", 590 op_name(op), (int)rn->tn_val.u.integer); 591 /* nonportable character comparison '%s' */ 592 warning(230, buf); 593 return false; 594 } 595 if (rt == CHAR && is_out_of_char_range(ln)) { 596 char buf[128]; 597 (void)snprintf(buf, sizeof(buf), "%d %s ?", 598 (int)ln->tn_val.u.integer, op_name(op)); 599 /* nonportable character comparison '%s' */ 600 warning(230, buf); 601 return false; 602 } 603 return true; 604 } 605 606 static void 607 check_integer_comparison(op_t op, tnode_t *ln, tnode_t *rn) 608 { 609 610 tspec_t lt = ln->tn_type->t_tspec; 611 tspec_t rt = rn->tn_type->t_tspec; 612 613 if (ln->tn_op != CON && rn->tn_op != CON) 614 return; 615 616 if (!is_integer(lt) || !is_integer(rt)) 617 return; 618 619 if (any_query_enabled && !in_system_header) { 620 if (lt == CHAR && rn->tn_op == CON && 621 !rn->tn_val.v_char_constant) { 622 /* comparison '%s' of 'char' with plain integer %d */ 623 query_message(14, 624 op_name(op), (int)rn->tn_val.u.integer); 625 } 626 if (rt == CHAR && ln->tn_op == CON && 627 !ln->tn_val.v_char_constant) { 628 /* comparison '%s' of 'char' with plain integer %d */ 629 query_message(14, 630 op_name(op), (int)ln->tn_val.u.integer); 631 } 632 } 633 634 if (!check_nonportable_char_comparison(op, ln, lt, rn, rt)) 635 return; 636 637 if (is_uinteger(lt) && !is_uinteger(rt) && 638 rn->tn_op == CON && rn->tn_val.u.integer <= 0) { 639 if (rn->tn_val.u.integer < 0) { 640 /* operator '%s' compares '%s' with '%s' */ 641 warning(162, op_name(op), 642 type_name(ln->tn_type), "negative constant"); 643 } else if (op == LT || op == GE) { 644 /* operator '%s' compares '%s' with '%s' */ 645 warning(162, op_name(op), type_name(ln->tn_type), "0"); 646 } 647 return; 648 } 649 if (is_uinteger(rt) && !is_uinteger(lt) && 650 ln->tn_op == CON && ln->tn_val.u.integer <= 0) { 651 if (ln->tn_val.u.integer < 0) { 652 /* operator '%s' compares '%s' with '%s' */ 653 warning(162, op_name(op), 654 "negative constant", type_name(rn->tn_type)); 655 } else if (op == GT || op == LE) { 656 /* operator '%s' compares '%s' with '%s' */ 657 warning(162, op_name(op), "0", type_name(rn->tn_type)); 658 } 659 return; 660 } 661 } 662 663 static const tspec_t arith_rank[] = { 664 LDOUBLE, DOUBLE, FLOAT, 665 #ifdef INT128_SIZE 666 UINT128, INT128, 667 #endif 668 ULLONG, LLONG, 669 ULONG, LONG, 670 UINT, INT, 671 }; 672 673 /* Keep unsigned in traditional C */ 674 static tspec_t 675 usual_arithmetic_conversion_trad(tspec_t lt, tspec_t rt) 676 { 677 678 size_t i; 679 for (i = 0; arith_rank[i] != INT; i++) 680 if (lt == arith_rank[i] || rt == arith_rank[i]) 681 break; 682 683 tspec_t t = arith_rank[i]; 684 if (is_uinteger(lt) || is_uinteger(rt)) 685 if (is_integer(t) && !is_uinteger(t)) 686 return unsigned_type(t); 687 return t; 688 } 689 690 static tspec_t 691 usual_arithmetic_conversion_c90(tspec_t lt, tspec_t rt) 692 { 693 694 if (lt == rt) 695 return lt; 696 697 if (lt == LCOMPLEX || rt == LCOMPLEX) 698 return LCOMPLEX; 699 if (lt == DCOMPLEX || rt == DCOMPLEX) 700 return DCOMPLEX; 701 if (lt == FCOMPLEX || rt == FCOMPLEX) 702 return FCOMPLEX; 703 if (lt == LDOUBLE || rt == LDOUBLE) 704 return LDOUBLE; 705 if (lt == DOUBLE || rt == DOUBLE) 706 return DOUBLE; 707 if (lt == FLOAT || rt == FLOAT) 708 return FLOAT; 709 710 if (size_in_bits(lt) > size_in_bits(rt)) 711 return lt; 712 if (size_in_bits(lt) < size_in_bits(rt)) 713 return rt; 714 715 size_t i; 716 for (i = 3; arith_rank[i] != INT; i++) 717 if (arith_rank[i] == lt || arith_rank[i] == rt) 718 break; 719 if ((is_uinteger(lt) || is_uinteger(rt)) && 720 !is_uinteger(arith_rank[i])) 721 i--; 722 return arith_rank[i]; 723 } 724 725 static tnode_t * 726 apply_usual_arithmetic_conversions(op_t op, tnode_t *tn, tspec_t t) 727 { 728 type_t *ntp = expr_dup_type(tn->tn_type); 729 ntp->t_tspec = t; 730 if (tn->tn_op != CON) { 731 /* usual arithmetic conversion for '%s' from '%s' to '%s' */ 732 query_message(4, op_name(op), 733 type_name(tn->tn_type), type_name(ntp)); 734 } 735 return convert(op, 0, ntp, tn); 736 } 737 738 /* 739 * Apply the "usual arithmetic conversions" (C99 6.3.1.8), which gives both 740 * operands the same type. 741 */ 742 static void 743 balance(op_t op, tnode_t **lnp, tnode_t **rnp) 744 { 745 746 tspec_t lt = (*lnp)->tn_type->t_tspec; 747 tspec_t rt = (*rnp)->tn_type->t_tspec; 748 if (!is_arithmetic(lt) || !is_arithmetic(rt)) 749 return; 750 751 tspec_t t = allow_c90 752 ? usual_arithmetic_conversion_c90(lt, rt) 753 : usual_arithmetic_conversion_trad(lt, rt); 754 755 if (t != lt) 756 *lnp = apply_usual_arithmetic_conversions(op, *lnp, t); 757 if (t != rt) 758 *rnp = apply_usual_arithmetic_conversions(op, *rnp, t); 759 } 760 761 static tnode_t * 762 build_address(bool sys, tnode_t *tn, bool force) 763 { 764 tspec_t t; 765 766 if (!force && ((t = tn->tn_type->t_tspec) == ARRAY || t == FUNC)) { 767 if (!allow_c90) 768 /* '&' before array or function: ignored */ 769 warning(127); 770 return tn; 771 } 772 773 /* eliminate '&*' */ 774 if (tn->tn_op == INDIR && 775 tn->tn_left->tn_type->t_tspec == PTR && 776 tn->tn_left->tn_type->t_subt == tn->tn_type) { 777 return tn->tn_left; 778 } 779 780 return build_op(ADDR, sys, expr_derive_type(tn->tn_type, PTR), 781 tn, NULL); 782 } 783 784 /* 785 * XXX 786 * Note: There appear to be a number of bugs in detecting overflow in 787 * this function. An audit and a set of proper regression tests are needed. 788 * --Perry Metzger, Nov. 16, 2001 789 */ 790 static tnode_t * 791 fold_constant_integer(tnode_t *tn) 792 { 793 794 val_t *v = xcalloc(1, sizeof(*v)); 795 v->v_tspec = tn->tn_type->t_tspec; 796 797 lint_assert(has_operands(tn)); 798 tspec_t t = tn->tn_left->tn_type->t_tspec; 799 bool utyp = !is_integer(t) || is_uinteger(t); 800 int64_t sl = tn->tn_left->tn_val.u.integer, sr = 0; 801 uint64_t ul = sl, ur = 0; 802 if (is_binary(tn)) 803 ur = sr = tn->tn_right->tn_val.u.integer; 804 805 uint64_t mask = value_bits(size_in_bits(t)); 806 bool ovfl = false; 807 808 int64_t si; 809 switch (tn->tn_op) { 810 case UPLUS: 811 si = sl; 812 break; 813 case UMINUS: 814 si = sl == INT64_MIN ? sl : -sl; 815 if (sl != 0 && msb(si, t) == msb(sl, t)) 816 ovfl = true; 817 break; 818 case COMPL: 819 si = ~sl; 820 break; 821 case MULT: 822 if (utyp) { 823 si = (int64_t)(ul * ur); 824 if (si != (si & (int64_t)mask)) 825 ovfl = true; 826 else if (ul != 0 && si / ul != ur) 827 ovfl = true; 828 } else { 829 si = sl * sr; 830 if (msb(si, t) != (msb(sl, t) ^ msb(sr, t))) 831 ovfl = true; 832 } 833 break; 834 case DIV: 835 if (sr == 0) { 836 /* division by 0 */ 837 error(139); 838 si = utyp ? -1 : INT64_MAX; 839 } else if (!utyp 840 && (sl & mask) == (mask ^ (mask >> 1)) && sr == -1) { 841 /* operator '%s' produces integer overflow */ 842 warning(141, op_name(DIV)); 843 si = sl; 844 } else { 845 si = utyp ? (int64_t)(ul / ur) : sl / sr; 846 } 847 break; 848 case MOD: 849 if (sr == 0) { 850 /* modulus by 0 */ 851 error(140); 852 si = 0; 853 } else { 854 si = utyp ? (int64_t)(ul % ur) : sl % sr; 855 } 856 break; 857 case PLUS: 858 si = utyp ? (int64_t)(ul + ur) : sl + sr; 859 if (msb(sl, t) && msb(sr, t) && !msb(si, t)) 860 ovfl = true; 861 if (!utyp && !msb(sl, t) && !msb(sr, t) && msb(si, t)) 862 ovfl = true; 863 break; 864 case MINUS: 865 si = utyp ? (int64_t)(ul - ur) : sl - sr; 866 if (!utyp && msb(sl, t) && !msb(sr, t) && !msb(si, t)) 867 ovfl = true; 868 if (!msb(sl, t) && msb(sr, t) && msb(si, t)) 869 ovfl = true; 870 break; 871 case SHL: 872 /* TODO: warn about out-of-bounds 'sr'. */ 873 /* TODO: warn about overflow in signed '<<'. */ 874 si = utyp ? (int64_t)(ul << (sr & 63)) : sl << (sr & 63); 875 break; 876 case SHR: 877 /* 878 * The sign must be explicitly extended because shifts of 879 * signed values are implementation dependent. 880 */ 881 /* TODO: warn about out-of-bounds 'sr'. */ 882 si = (int64_t)(ul >> (sr & 63)); 883 si = convert_integer(si, t, size_in_bits(t) - (int)sr); 884 break; 885 case LT: 886 si = (utyp ? ul < ur : sl < sr) ? 1 : 0; 887 break; 888 case LE: 889 si = (utyp ? ul <= ur : sl <= sr) ? 1 : 0; 890 break; 891 case GE: 892 si = (utyp ? ul >= ur : sl >= sr) ? 1 : 0; 893 break; 894 case GT: 895 si = (utyp ? ul > ur : sl > sr) ? 1 : 0; 896 break; 897 case EQ: 898 si = (utyp ? ul == ur : sl == sr) ? 1 : 0; 899 break; 900 case NE: 901 si = (utyp ? ul != ur : sl != sr) ? 1 : 0; 902 break; 903 case BITAND: 904 si = utyp ? (int64_t)(ul & ur) : sl & sr; 905 break; 906 case BITXOR: 907 si = utyp ? (int64_t)(ul ^ ur) : sl ^ sr; 908 break; 909 case BITOR: 910 si = utyp ? (int64_t)(ul | ur) : sl | sr; 911 break; 912 default: 913 lint_assert(/*CONSTCOND*/false); 914 } 915 916 /* XXX: The overflow check does not work for 64-bit integers. */ 917 if (ovfl || 918 ((si | mask) != ~(uint64_t)0 && (si & ~mask) != 0)) { 919 if (hflag) 920 /* operator '%s' produces integer overflow */ 921 warning(141, op_name(tn->tn_op)); 922 } 923 924 v->u.integer = convert_integer(si, t, 0); 925 926 tnode_t *cn = build_constant(tn->tn_type, v); 927 if (tn->tn_left->tn_system_dependent) 928 cn->tn_system_dependent = true; 929 if (is_binary(tn) && tn->tn_right->tn_system_dependent) 930 cn->tn_system_dependent = true; 931 932 return cn; 933 } 934 935 static tnode_t * 936 build_struct_access(op_t op, bool sys, tnode_t *ln, tnode_t *rn) 937 { 938 939 lint_assert(rn->tn_op == NAME); 940 lint_assert(is_member(rn->tn_sym)); 941 942 bool lvalue = op == ARROW || ln->tn_lvalue; 943 944 if (op == POINT) { 945 ln = build_address(sys, ln, true); 946 } else if (ln->tn_type->t_tspec != PTR) { 947 lint_assert(!allow_c90); 948 lint_assert(is_integer(ln->tn_type->t_tspec)); 949 ln = convert(NOOP, 0, expr_derive_type(gettyp(VOID), PTR), ln); 950 } 951 952 tnode_t *ctn = build_integer_constant(PTRDIFF_TSPEC, 953 rn->tn_sym->u.s_member.sm_offset_in_bits / CHAR_SIZE); 954 955 type_t *ptr_tp = expr_derive_type(rn->tn_type, PTR); 956 tnode_t *ntn = build_op(PLUS, sys, ptr_tp, ln, ctn); 957 if (ln->tn_op == CON) 958 ntn = fold_constant_integer(ntn); 959 960 op_t nop = rn->tn_type->t_bitfield ? FSEL : INDIR; 961 ntn = build_op(nop, sys, ntn->tn_type->t_subt, ntn, NULL); 962 if (!lvalue) 963 ntn->tn_lvalue = false; 964 965 return ntn; 966 } 967 968 /* 969 * Get the size in bytes of type tp->t_subt, as a constant expression of type 970 * ptrdiff_t as seen from the target platform. 971 */ 972 static tnode_t * 973 subt_size_in_bytes(type_t *tp) 974 { 975 976 lint_assert(tp->t_tspec == PTR); 977 tp = tp->t_subt; 978 979 int elem = 1; 980 while (tp->t_tspec == ARRAY) { 981 elem *= tp->t_dim; 982 tp = tp->t_subt; 983 } 984 985 int elsz_in_bits = 0; 986 switch (tp->t_tspec) { 987 case FUNC: 988 /* pointer to function is not allowed here */ 989 error(110); 990 break; 991 case VOID: 992 /* cannot do pointer arithmetic on operand of unknown size */ 993 gnuism(136); 994 break; 995 case STRUCT: 996 case UNION: 997 if ((elsz_in_bits = (int)tp->t_sou->sou_size_in_bits) == 0) 998 /* cannot do pointer arithmetic on operand of ... */ 999 error(136); 1000 break; 1001 case ENUM: 1002 if (is_incomplete(tp)) { 1003 /* cannot do pointer arithmetic on operand of ... */ 1004 warning(136); 1005 } 1006 /* FALLTHROUGH */ 1007 default: 1008 if ((elsz_in_bits = size_in_bits(tp->t_tspec)) == 0) { 1009 /* cannot do pointer arithmetic on operand of ... */ 1010 error(136); 1011 } else { 1012 lint_assert(elsz_in_bits != -1); 1013 } 1014 break; 1015 } 1016 1017 if (elem == 0 && elsz_in_bits != 0) { 1018 /* cannot do pointer arithmetic on operand of unknown size */ 1019 error(136); 1020 } 1021 1022 if (elsz_in_bits == 0) 1023 elsz_in_bits = CHAR_SIZE; 1024 1025 return build_integer_constant(PTRDIFF_TSPEC, 1026 (int64_t)(elem * elsz_in_bits / CHAR_SIZE)); 1027 } 1028 1029 static tnode_t * 1030 build_prepost_incdec(op_t op, bool sys, tnode_t *ln) 1031 { 1032 1033 lint_assert(ln != NULL); 1034 tnode_t *cn = ln->tn_type->t_tspec == PTR 1035 ? subt_size_in_bytes(ln->tn_type) 1036 : build_integer_constant(INT, 1); 1037 return build_op(op, sys, ln->tn_type, ln, cn); 1038 } 1039 1040 static void 1041 check_enum_array_index(const tnode_t *ln, const tnode_t *rn) 1042 { 1043 1044 if (ln->tn_op != ADDR || ln->tn_left->tn_op != NAME) 1045 return; 1046 1047 const type_t *ltp = ln->tn_left->tn_type; 1048 if (ltp->t_tspec != ARRAY || ltp->t_incomplete_array) 1049 return; 1050 1051 if (rn->tn_op != CVT || !rn->tn_type->t_is_enum) 1052 return; 1053 if (rn->tn_left->tn_op != LOAD) 1054 return; 1055 1056 const type_t *rtp = rn->tn_left->tn_type; 1057 const sym_t *ec = rtp->t_enum->en_first_enumerator; 1058 const sym_t *max_ec = ec; 1059 lint_assert(ec != NULL); 1060 for (ec = ec->s_next; ec != NULL; ec = ec->s_next) 1061 if (ec->u.s_enum_constant > max_ec->u.s_enum_constant) 1062 max_ec = ec; 1063 1064 int64_t max_enum_value = max_ec->u.s_enum_constant; 1065 lint_assert(INT_MIN <= max_enum_value && max_enum_value <= INT_MAX); 1066 1067 int max_array_index = ltp->t_dim - 1; 1068 if (max_enum_value == max_array_index) 1069 return; 1070 1071 if (max_enum_value == max_array_index + 1 && 1072 (strstr(max_ec->s_name, "MAX") != NULL || 1073 strstr(max_ec->s_name, "max") != NULL || 1074 strstr(max_ec->s_name, "NUM") != NULL || 1075 strstr(max_ec->s_name, "num") != NULL)) 1076 return; 1077 1078 /* maximum value %d of '%s' does not match maximum array index %d */ 1079 warning(348, (int)max_enum_value, type_name(rtp), max_array_index); 1080 print_previous_declaration(max_ec); 1081 } 1082 1083 static tnode_t * 1084 build_plus_minus(op_t op, bool sys, tnode_t *ln, tnode_t *rn) 1085 { 1086 1087 if (rn->tn_type->t_tspec == PTR && is_integer(ln->tn_type->t_tspec)) { 1088 tnode_t *tmp = ln; 1089 ln = rn; 1090 rn = tmp; 1091 /* pointer addition has integer on the left-hand side */ 1092 query_message(5); 1093 } 1094 1095 /* pointer +- integer */ 1096 if (ln->tn_type->t_tspec == PTR && rn->tn_type->t_tspec != PTR) { 1097 lint_assert(is_integer(rn->tn_type->t_tspec)); 1098 1099 check_ctype_macro_invocation(ln, rn); 1100 check_enum_array_index(ln, rn); 1101 1102 tnode_t *elsz = subt_size_in_bytes(ln->tn_type); 1103 if (rn->tn_type->t_tspec != elsz->tn_type->t_tspec) 1104 rn = convert(NOOP, 0, elsz->tn_type, rn); 1105 1106 tnode_t *prod = build_op(MULT, sys, rn->tn_type, rn, elsz); 1107 if (rn->tn_op == CON) 1108 prod = fold_constant_integer(prod); 1109 1110 return build_op(op, sys, ln->tn_type, ln, prod); 1111 } 1112 1113 /* pointer - pointer */ 1114 if (rn->tn_type->t_tspec == PTR) { 1115 lint_assert(ln->tn_type->t_tspec == PTR); 1116 lint_assert(op == MINUS); 1117 1118 type_t *ptrdiff = gettyp(PTRDIFF_TSPEC); 1119 tnode_t *raw_diff = build_op(op, sys, ptrdiff, ln, rn); 1120 if (ln->tn_op == CON && rn->tn_op == CON) 1121 raw_diff = fold_constant_integer(raw_diff); 1122 1123 tnode_t *elsz = subt_size_in_bytes(ln->tn_type); 1124 balance(NOOP, &raw_diff, &elsz); 1125 1126 return build_op(DIV, sys, ptrdiff, raw_diff, elsz); 1127 } 1128 1129 return build_op(op, sys, ln->tn_type, ln, rn); 1130 } 1131 1132 static tnode_t * 1133 build_bit_shift(op_t op, bool sys, tnode_t *ln, tnode_t *rn) 1134 { 1135 1136 if (!allow_c90 && rn->tn_type->t_tspec != INT) 1137 // XXX: C1978 7.5 says: "Both [operators] perform the usual 1138 // arithmetic conversions on their operands." 1139 // TODO: Add a test to exercise this part of the code. 1140 rn = convert(NOOP, 0, gettyp(INT), rn); 1141 return build_op(op, sys, ln->tn_type, ln, rn); 1142 } 1143 1144 static bool 1145 is_null_pointer(const tnode_t *tn) 1146 { 1147 tspec_t t = tn->tn_type->t_tspec; 1148 1149 // TODO: Investigate how other pointers are stored, in particular, 1150 // whether a pointer constant can have a non-zero value. 1151 // If not, simplify the code below. 1152 return ((t == PTR && tn->tn_type->t_subt->t_tspec == VOID) 1153 || is_integer(t)) 1154 && (tn->tn_op == CON && tn->tn_val.u.integer == 0); 1155 } 1156 1157 /* Return a type based on tp1, with added qualifiers from tp2. */ 1158 static type_t * 1159 merge_qualifiers(type_t *tp1, const type_t *tp2) 1160 { 1161 1162 lint_assert(tp1->t_tspec == PTR); 1163 lint_assert(tp2->t_tspec == PTR); 1164 1165 bool c1 = tp1->t_subt->t_const; 1166 bool c2 = tp2->t_subt->t_const; 1167 bool v1 = tp1->t_subt->t_volatile; 1168 bool v2 = tp2->t_subt->t_volatile; 1169 1170 if (c1 == (c1 | c2) && v1 == (v1 | v2)) 1171 return tp1; 1172 1173 type_t *nstp = expr_dup_type(tp1->t_subt); 1174 nstp->t_const |= c2; 1175 nstp->t_volatile |= v2; 1176 1177 type_t *ntp = expr_dup_type(tp1); 1178 ntp->t_subt = nstp; 1179 return ntp; 1180 } 1181 1182 /* See C99 6.5.15 "Conditional operator". */ 1183 static tnode_t * 1184 build_colon(bool sys, tnode_t *ln, tnode_t *rn) 1185 { 1186 tspec_t lt = ln->tn_type->t_tspec; 1187 tspec_t rt = rn->tn_type->t_tspec; 1188 1189 type_t *tp; 1190 if (is_arithmetic(lt) && is_arithmetic(rt)) { 1191 /* The operands were already balanced in build_binary. */ 1192 tp = ln->tn_type; 1193 } else if (lt == BOOL && rt == BOOL) { 1194 tp = ln->tn_type; 1195 } else if (lt == VOID || rt == VOID) { 1196 tp = gettyp(VOID); 1197 } else if (is_struct_or_union(lt)) { 1198 lint_assert(is_struct_or_union(rt)); 1199 lint_assert(ln->tn_type->t_sou == rn->tn_type->t_sou); 1200 if (is_incomplete(ln->tn_type)) { 1201 /* unknown operand size, op '%s' */ 1202 error(138, op_name(COLON)); 1203 return NULL; 1204 } 1205 tp = ln->tn_type; 1206 } else if (lt == PTR && is_integer(rt)) { 1207 if (rt != PTRDIFF_TSPEC) 1208 rn = convert(NOOP, 0, gettyp(PTRDIFF_TSPEC), rn); 1209 tp = ln->tn_type; 1210 } else if (rt == PTR && is_integer(lt)) { 1211 if (lt != PTRDIFF_TSPEC) 1212 ln = convert(NOOP, 0, gettyp(PTRDIFF_TSPEC), ln); 1213 tp = rn->tn_type; 1214 } else if (lt == PTR && is_null_pointer(rn)) { 1215 tp = merge_qualifiers(ln->tn_type, rn->tn_type); 1216 } else if (rt == PTR && is_null_pointer(ln)) { 1217 tp = merge_qualifiers(rn->tn_type, ln->tn_type); 1218 } else if (lt == PTR && ln->tn_type->t_subt->t_tspec == VOID) { 1219 tp = merge_qualifiers(ln->tn_type, rn->tn_type); 1220 } else if (rt == PTR && rn->tn_type->t_subt->t_tspec == VOID) { 1221 tp = merge_qualifiers(rn->tn_type, ln->tn_type); 1222 } else { 1223 /* 1224 * XXX For now we simply take the left type. This is probably 1225 * wrong, if one type contains a function prototype and the 1226 * other one, at the same place, only an old-style declaration. 1227 */ 1228 tp = merge_qualifiers(ln->tn_type, rn->tn_type); 1229 } 1230 1231 return build_op(COLON, sys, tp, ln, rn); 1232 } 1233 1234 /* TODO: check for varargs */ 1235 static bool 1236 is_cast_redundant(const tnode_t *tn) 1237 { 1238 const type_t *ntp = tn->tn_type, *otp = tn_ck_left(tn)->tn_type; 1239 tspec_t nt = ntp->t_tspec, ot = otp->t_tspec; 1240 1241 if (nt == BOOL || ot == BOOL) 1242 return nt == BOOL && ot == BOOL; 1243 1244 if (is_integer(nt) && is_integer(ot)) { 1245 unsigned int nw = width_in_bits(ntp), ow = width_in_bits(otp); 1246 if (is_uinteger(nt) == is_uinteger(ot)) 1247 return nw >= ow; 1248 return is_uinteger(ot) && nw > ow; 1249 } 1250 1251 if (is_complex(nt) || is_complex(ot)) 1252 return is_complex(nt) && is_complex(ot) && 1253 size_in_bits(nt) >= size_in_bits(ot); 1254 1255 if (is_floating(nt) && is_floating(ot)) 1256 return size_in_bits(nt) >= size_in_bits(ot); 1257 1258 if (nt == PTR && ot == PTR) { 1259 if (!ntp->t_subt->t_const && otp->t_subt->t_const) 1260 return false; 1261 if (!ntp->t_subt->t_volatile && otp->t_subt->t_volatile) 1262 return false; 1263 1264 if (ntp->t_subt->t_tspec == VOID || 1265 otp->t_subt->t_tspec == VOID || 1266 types_compatible(ntp->t_subt, otp->t_subt, 1267 false, false, NULL)) 1268 return true; 1269 } 1270 1271 return false; 1272 } 1273 1274 static bool 1275 is_assignment(op_t op) 1276 { 1277 1278 return op == ASSIGN || 1279 op == MULASS || 1280 op == DIVASS || 1281 op == MODASS || 1282 op == ADDASS || 1283 op == SUBASS || 1284 op == SHLASS || 1285 op == SHRASS || 1286 op == ANDASS || 1287 op == XORASS || 1288 op == ORASS || 1289 op == RETURN || 1290 op == INIT; 1291 } 1292 1293 static tnode_t * 1294 build_assignment(op_t op, bool sys, tnode_t *ln, tnode_t *rn) 1295 { 1296 1297 tspec_t lt = ln->tn_type->t_tspec; 1298 tspec_t rt = rn->tn_type->t_tspec; 1299 1300 if (any_query_enabled && is_assignment(rn->tn_op)) { 1301 /* chained assignment with '%s' and '%s' */ 1302 query_message(10, op_name(op), op_name(rn->tn_op)); 1303 } 1304 1305 if ((op == ADDASS || op == SUBASS) && lt == PTR) { 1306 lint_assert(is_integer(rt)); 1307 tnode_t *ctn = subt_size_in_bytes(ln->tn_type); 1308 if (rn->tn_type->t_tspec != ctn->tn_type->t_tspec) 1309 rn = convert(NOOP, 0, ctn->tn_type, rn); 1310 rn = build_op(MULT, sys, rn->tn_type, rn, ctn); 1311 if (rn->tn_left->tn_op == CON) 1312 rn = fold_constant_integer(rn); 1313 } 1314 1315 if ((op == ASSIGN || op == RETURN || op == INIT) && 1316 (lt == STRUCT || rt == STRUCT)) { 1317 lint_assert(lt == rt); 1318 lint_assert(ln->tn_type->t_sou == rn->tn_type->t_sou); 1319 if (is_incomplete(ln->tn_type)) { 1320 if (op == RETURN) { 1321 /* cannot return incomplete type */ 1322 error(212); 1323 } else { 1324 /* unknown operand size, op '%s' */ 1325 error(138, op_name(op)); 1326 } 1327 return NULL; 1328 } 1329 } 1330 1331 if (op == SHLASS && hflag && allow_trad && allow_c90 1332 && portable_rank_cmp(lt, rt) < 0) 1333 /* semantics of '%s' change in C90; ... */ 1334 warning(118, "<<="); 1335 1336 if (op != SHLASS && op != SHRASS 1337 && (op == ASSIGN || lt != PTR) 1338 && (lt != rt || (ln->tn_type->t_bitfield && rn->tn_op == CON))) { 1339 rn = convert(op, 0, ln->tn_type, rn); 1340 rt = lt; 1341 } 1342 1343 if (any_query_enabled && rn->tn_op == CVT && rn->tn_cast && 1344 types_compatible(ln->tn_type, rn->tn_type, false, false, NULL) && 1345 is_cast_redundant(rn)) { 1346 /* redundant cast from '%s' to '%s' before assignment */ 1347 query_message(7, 1348 type_name(rn->tn_left->tn_type), type_name(rn->tn_type)); 1349 } 1350 1351 return build_op(op, sys, ln->tn_type, ln, rn); 1352 } 1353 1354 static tnode_t * 1355 build_real_imag(op_t op, bool sys, tnode_t *ln) 1356 { 1357 1358 lint_assert(ln != NULL); 1359 if (ln->tn_op == NAME) { 1360 /* 1361 * This may be too much, but it avoids wrong warnings. See 1362 * d_c99_complex_split.c. 1363 */ 1364 mark_as_used(ln->tn_sym, false, false); 1365 mark_as_set(ln->tn_sym); 1366 } 1367 1368 tspec_t t; 1369 switch (ln->tn_type->t_tspec) { 1370 case LCOMPLEX: 1371 t = LDOUBLE; 1372 break; 1373 case DCOMPLEX: 1374 t = DOUBLE; 1375 break; 1376 case FCOMPLEX: 1377 t = FLOAT; 1378 break; 1379 default: 1380 /* '__%s__' is illegal for type '%s' */ 1381 error(276, op == REAL ? "real" : "imag", 1382 type_name(ln->tn_type)); 1383 return NULL; 1384 } 1385 1386 tnode_t *ntn = build_op(op, sys, gettyp(t), ln, NULL); 1387 ntn->tn_lvalue = true; 1388 return ntn; 1389 } 1390 1391 static bool 1392 is_confusing_precedence(op_t op, op_t lop, bool lparen, op_t rop, bool rparen) 1393 { 1394 1395 if (op == SHL || op == SHR) { 1396 if (!lparen && (lop == PLUS || lop == MINUS)) 1397 return true; 1398 if (!rparen && (rop == PLUS || rop == MINUS)) 1399 return true; 1400 return false; 1401 } 1402 1403 if (op == LOGOR) { 1404 if (!lparen && lop == LOGAND) 1405 return true; 1406 if (!rparen && rop == LOGAND) 1407 return true; 1408 return false; 1409 } 1410 1411 lint_assert(op == BITAND || op == BITXOR || op == BITOR); 1412 if (!lparen && lop != op) { 1413 if (lop == PLUS || lop == MINUS) 1414 return true; 1415 if (lop == BITAND || lop == BITXOR) 1416 return true; 1417 } 1418 if (!rparen && rop != op) { 1419 if (rop == PLUS || rop == MINUS) 1420 return true; 1421 if (rop == BITAND || rop == BITXOR) 1422 return true; 1423 } 1424 return false; 1425 } 1426 1427 /* 1428 * Print a warning if the given node has operands which should be 1429 * parenthesized. 1430 * 1431 * XXX Does not work if an operand is a constant expression. Constant 1432 * expressions are already folded. 1433 */ 1434 static void 1435 check_precedence_confusion(tnode_t *tn) 1436 { 1437 tnode_t *ln, *rn; 1438 1439 if (!hflag) 1440 return; 1441 1442 debug_node(tn); 1443 1444 lint_assert(is_binary(tn)); 1445 for (ln = tn->tn_left; ln->tn_op == CVT; ln = ln->tn_left) 1446 continue; 1447 for (rn = tn->tn_right; rn->tn_op == CVT; rn = rn->tn_left) 1448 continue; 1449 1450 if (is_confusing_precedence(tn->tn_op, 1451 ln->tn_op, ln->tn_parenthesized, 1452 rn->tn_op, rn->tn_parenthesized)) { 1453 /* precedence confusion possible: parenthesize! */ 1454 warning(169); 1455 } 1456 } 1457 1458 static tnode_t * 1459 fold_constant_compare_zero(tnode_t *tn) 1460 { 1461 1462 val_t *v = xcalloc(1, sizeof(*v)); 1463 v->v_tspec = tn->tn_type->t_tspec; 1464 lint_assert(v->v_tspec == INT || (Tflag && v->v_tspec == BOOL)); 1465 1466 lint_assert(has_operands(tn)); 1467 bool l = constant_is_nonzero(tn->tn_left); 1468 bool r = is_binary(tn) && constant_is_nonzero(tn->tn_right); 1469 1470 switch (tn->tn_op) { 1471 case NOT: 1472 if (hflag && !suppress_constcond) 1473 /* constant operand to '!' */ 1474 warning(239); 1475 v->u.integer = !l ? 1 : 0; 1476 break; 1477 case LOGAND: 1478 v->u.integer = l && r ? 1 : 0; 1479 break; 1480 case LOGOR: 1481 v->u.integer = l || r ? 1 : 0; 1482 break; 1483 default: 1484 lint_assert(/*CONSTCOND*/false); 1485 } 1486 1487 return build_constant(tn->tn_type, v); 1488 } 1489 1490 static long double 1491 floating_error_value(tspec_t t, long double lv) 1492 { 1493 if (t == FLOAT) 1494 return lv < 0 ? -FLT_MAX : FLT_MAX; 1495 if (t == DOUBLE) 1496 return lv < 0 ? -DBL_MAX : DBL_MAX; 1497 /* 1498 * When NetBSD is cross-built in MKLINT=yes mode on x86_64 for sparc64, 1499 * tools/lint checks this code while building usr.bin/xlint. In that 1500 * situation, lint uses the preprocessor for sparc64, in which the type 1501 * 'long double' is IEEE-754-binary128, affecting the macro LDBL_MAX 1502 * below. The type 'long double', as well as the strtold 1503 * implementation, comes from the host platform x86_64 though, where 1504 * 'long double' consumes 128 bits as well but only uses 80 of them. 1505 * The exponent range of the two 'long double' types is the same, but 1506 * the maximum finite value differs due to the extended precision on 1507 * sparc64. 1508 * 1509 * To properly handle the data types of the target platform, lint would 1510 * have to implement the floating-point types in a platform-independent 1511 * way, which is not worth the effort, given how few programs 1512 * practically use 'long double'. 1513 */ 1514 /* LINTED 248: floating-point constant out of range */ 1515 long double max = LDBL_MAX; 1516 return lv < 0 ? -max : max; 1517 } 1518 1519 static bool 1520 is_floating_overflow(tspec_t t, long double val) 1521 { 1522 if (fpe != 0 || isfinite(val) == 0) 1523 return true; 1524 if (t == FLOAT && (val > FLT_MAX || val < -FLT_MAX)) 1525 return true; 1526 if (t == DOUBLE && (val > DBL_MAX || val < -DBL_MAX)) 1527 return true; 1528 return false; 1529 } 1530 1531 static tnode_t * 1532 fold_constant_floating(tnode_t *tn) 1533 { 1534 1535 fpe = 0; 1536 1537 tspec_t t = tn->tn_type->t_tspec; 1538 1539 val_t *v = xcalloc(1, sizeof(*v)); 1540 v->v_tspec = t; 1541 1542 lint_assert(is_floating(t)); 1543 lint_assert(has_operands(tn)); 1544 lint_assert(t == tn->tn_left->tn_type->t_tspec); 1545 lint_assert(!is_binary(tn) || t == tn->tn_right->tn_type->t_tspec); 1546 1547 long double lv = tn->tn_left->tn_val.u.floating; 1548 long double rv = is_binary(tn) ? tn->tn_right->tn_val.u.floating : 0.0; 1549 1550 switch (tn->tn_op) { 1551 case UPLUS: 1552 v->u.floating = lv; 1553 break; 1554 case UMINUS: 1555 v->u.floating = -lv; 1556 break; 1557 case MULT: 1558 v->u.floating = lv * rv; 1559 break; 1560 case DIV: 1561 if (rv == 0.0) { 1562 /* division by 0 */ 1563 error(139); 1564 v->u.floating = floating_error_value(t, lv); 1565 } else { 1566 v->u.floating = lv / rv; 1567 } 1568 break; 1569 case PLUS: 1570 v->u.floating = lv + rv; 1571 break; 1572 case MINUS: 1573 v->u.floating = lv - rv; 1574 break; 1575 case LT: 1576 v->u.integer = lv < rv ? 1 : 0; 1577 break; 1578 case LE: 1579 v->u.integer = lv <= rv ? 1 : 0; 1580 break; 1581 case GE: 1582 v->u.integer = lv >= rv ? 1 : 0; 1583 break; 1584 case GT: 1585 v->u.integer = lv > rv ? 1 : 0; 1586 break; 1587 case EQ: 1588 v->u.integer = lv == rv ? 1 : 0; 1589 break; 1590 case NE: 1591 v->u.integer = lv != rv ? 1 : 0; 1592 break; 1593 default: 1594 lint_assert(/*CONSTCOND*/false); 1595 } 1596 1597 // XXX: Must not access u.floating after setting u.integer. 1598 lint_assert(fpe != 0 || isnan(v->u.floating) == 0); 1599 if (is_complex(v->v_tspec)) { 1600 /* 1601 * Don't warn, as lint doesn't model the imaginary part of 1602 * complex numbers. 1603 */ 1604 fpe = 0; 1605 } else if (is_floating_overflow(t, v->u.floating)) { 1606 /* operator '%s' produces floating point overflow */ 1607 warning(142, op_name(tn->tn_op)); 1608 v->u.floating = floating_error_value(t, v->u.floating); 1609 fpe = 0; 1610 } 1611 1612 return build_constant(tn->tn_type, v); 1613 } 1614 1615 static void 1616 use(const tnode_t *tn) 1617 { 1618 if (tn == NULL) 1619 return; 1620 switch (tn->tn_op) { 1621 case NAME: 1622 mark_as_used(tn->tn_sym, false /* XXX */, false /* XXX */); 1623 break; 1624 case CON: 1625 case STRING: 1626 break; 1627 default: 1628 lint_assert(has_operands(tn)); 1629 use(tn->tn_left); 1630 if (is_binary(tn) || tn->tn_op == PUSH) 1631 use(tn->tn_right); 1632 } 1633 } 1634 1635 /* 1636 * Create a tree node for a binary operator and its two operands. Also called 1637 * for unary operators; in that case rn is NULL. 1638 * 1639 * Function calls, sizeof and casts are handled elsewhere. 1640 */ 1641 tnode_t * 1642 build_binary(tnode_t *ln, op_t op, bool sys, tnode_t *rn) 1643 { 1644 const mod_t *mp = &modtab[op]; 1645 1646 /* If there was an error in one of the operands, return. */ 1647 if (ln == NULL || (mp->m_binary && rn == NULL)) 1648 return NULL; 1649 1650 if (mp->m_value_context || mp->m_compares_with_zero) 1651 ln = cconv(ln); 1652 if (mp->m_binary && op != ARROW && op != POINT) 1653 rn = cconv(rn); 1654 1655 if (mp->m_comparison) 1656 check_integer_comparison(op, ln, rn); 1657 1658 if (mp->m_value_context || mp->m_compares_with_zero) 1659 ln = promote(op, false, ln); 1660 if (mp->m_binary && op != ARROW && op != POINT && 1661 op != ASSIGN && op != RETURN && op != INIT) 1662 rn = promote(op, false, rn); 1663 1664 if (mp->m_warn_if_left_unsigned_in_c90 && 1665 ln->tn_op == CON && ln->tn_val.v_unsigned_since_c90) { 1666 /* C90 treats constant as unsigned, op '%s' */ 1667 warning(218, op_name(op)); 1668 ln->tn_val.v_unsigned_since_c90 = false; 1669 } 1670 if (mp->m_warn_if_right_unsigned_in_c90 && 1671 rn->tn_op == CON && rn->tn_val.v_unsigned_since_c90) { 1672 /* C90 treats constant as unsigned, op '%s' */ 1673 warning(218, op_name(op)); 1674 rn->tn_val.v_unsigned_since_c90 = false; 1675 } 1676 1677 if (mp->m_balance_operands || (!allow_c90 && (op == SHL || op == SHR))) 1678 balance(op, &ln, &rn); 1679 1680 if (!typeok(op, 0, ln, rn)) 1681 return NULL; 1682 1683 tnode_t *ntn; 1684 switch (op) { 1685 case POINT: 1686 case ARROW: 1687 ntn = build_struct_access(op, sys, ln, rn); 1688 break; 1689 case INCAFT: 1690 case DECAFT: 1691 case INCBEF: 1692 case DECBEF: 1693 ntn = build_prepost_incdec(op, sys, ln); 1694 break; 1695 case ADDR: 1696 ntn = build_address(sys, ln, false); 1697 break; 1698 case INDIR: 1699 ntn = build_op(INDIR, sys, ln->tn_type->t_subt, ln, NULL); 1700 break; 1701 case PLUS: 1702 case MINUS: 1703 ntn = build_plus_minus(op, sys, ln, rn); 1704 break; 1705 case SHL: 1706 case SHR: 1707 ntn = build_bit_shift(op, sys, ln, rn); 1708 break; 1709 case COLON: 1710 ntn = build_colon(sys, ln, rn); 1711 break; 1712 case ASSIGN: 1713 case MULASS: 1714 case DIVASS: 1715 case MODASS: 1716 case ADDASS: 1717 case SUBASS: 1718 case SHLASS: 1719 case SHRASS: 1720 case ANDASS: 1721 case XORASS: 1722 case ORASS: 1723 case RETURN: 1724 case INIT: 1725 ntn = build_assignment(op, sys, ln, rn); 1726 break; 1727 case COMMA: 1728 if (any_query_enabled) { 1729 /* comma operator with types '%s' and '%s' */ 1730 query_message(12, 1731 type_name(ln->tn_type), type_name(rn->tn_type)); 1732 } 1733 /* FALLTHROUGH */ 1734 case QUEST: 1735 ntn = build_op(op, sys, rn->tn_type, ln, rn); 1736 break; 1737 case REAL: 1738 case IMAG: 1739 ntn = build_real_imag(op, sys, ln); 1740 break; 1741 default: 1742 lint_assert(mp->m_binary == (rn != NULL)); 1743 type_t *rettp = mp->m_returns_bool 1744 ? gettyp(Tflag ? BOOL : INT) : ln->tn_type; 1745 ntn = build_op(op, sys, rettp, ln, rn); 1746 break; 1747 } 1748 1749 if (ntn == NULL) 1750 return NULL; 1751 1752 if (mp->m_possible_precedence_confusion) 1753 check_precedence_confusion(ntn); 1754 1755 if (hflag && !suppress_constcond && 1756 mp->m_compares_with_zero && 1757 (ln->tn_op == CON || 1758 (mp->m_binary && op != QUEST && rn->tn_op == CON)) && 1759 /* XXX: rn->tn_system_dependent should be checked as well */ 1760 !ln->tn_system_dependent) { 1761 /* constant in conditional context */ 1762 warning(161); 1763 } 1764 1765 if (mp->m_fold_constant_operands && ln->tn_op == CON) { 1766 if (!mp->m_binary || rn->tn_op == CON) { 1767 if (mp->m_compares_with_zero) 1768 ntn = fold_constant_compare_zero(ntn); 1769 else if (is_floating(ntn->tn_type->t_tspec)) 1770 ntn = fold_constant_floating(ntn); 1771 else 1772 ntn = fold_constant_integer(ntn); 1773 } else if (op == QUEST) { 1774 lint_assert(has_operands(rn)); 1775 use(ln->tn_val.u.integer != 0 1776 ? rn->tn_right : rn->tn_left); 1777 ntn = ln->tn_val.u.integer != 0 1778 ? rn->tn_left : rn->tn_right; 1779 } 1780 } 1781 1782 return ntn; 1783 } 1784 1785 tnode_t * 1786 build_unary(op_t op, bool sys, tnode_t *tn) 1787 { 1788 return build_binary(tn, op, sys, NULL); 1789 } 1790 1791 static bool 1792 are_members_compatible(const sym_t *a, const sym_t *b) 1793 { 1794 if (a->u.s_member.sm_offset_in_bits != b->u.s_member.sm_offset_in_bits) 1795 return false; 1796 1797 const type_t *atp = a->s_type; 1798 const type_t *btp = b->s_type; 1799 bool w = false; 1800 if (!types_compatible(atp, btp, false, false, &w) && !w) 1801 return false; 1802 if (a->s_bitfield != b->s_bitfield) 1803 return false; 1804 if (a->s_bitfield) { 1805 if (atp->t_bit_field_width != btp->t_bit_field_width) 1806 return false; 1807 if (atp->t_bit_field_offset != btp->t_bit_field_offset) 1808 return false; 1809 } 1810 return true; 1811 } 1812 1813 /* 1814 * Return whether all struct/union members with the same name have the same 1815 * type and offset. 1816 */ 1817 static bool 1818 all_members_compatible(const sym_t *msym) 1819 { 1820 for (const sym_t *csym = msym; 1821 csym != NULL; csym = csym->s_symtab_next) { 1822 if (!is_member(csym)) 1823 continue; 1824 if (strcmp(msym->s_name, csym->s_name) != 0) 1825 continue; 1826 1827 for (const sym_t *sym = csym->s_symtab_next; 1828 sym != NULL; sym = sym->s_symtab_next) { 1829 if (is_member(sym) 1830 && strcmp(csym->s_name, sym->s_name) == 0 1831 && !are_members_compatible(csym, sym)) 1832 return false; 1833 } 1834 } 1835 return true; 1836 } 1837 1838 sym_t * 1839 find_member(const struct_or_union *sou, const char *name) 1840 { 1841 for (sym_t *mem = sou->sou_first_member; 1842 mem != NULL; mem = mem->s_next) { 1843 lint_assert(is_member(mem)); 1844 lint_assert(mem->u.s_member.sm_containing_type == sou); 1845 if (strcmp(mem->s_name, name) == 0) 1846 return mem; 1847 } 1848 1849 for (sym_t *mem = sou->sou_first_member; 1850 mem != NULL; mem = mem->s_next) { 1851 if (is_struct_or_union(mem->s_type->t_tspec) 1852 && mem->s_name == unnamed) { 1853 sym_t *nested_mem = 1854 find_member(mem->s_type->t_sou, name); 1855 if (nested_mem != NULL) 1856 return nested_mem; 1857 } 1858 } 1859 return NULL; 1860 } 1861 1862 /* 1863 * Remove the member if it was unknown until now, which means 1864 * that no defined struct or union has a member with the same name. 1865 */ 1866 static void 1867 remove_unknown_member(tnode_t *tn, sym_t *msym) 1868 { 1869 /* type '%s' does not have member '%s' */ 1870 error(101, type_name(tn->tn_type), msym->s_name); 1871 rmsym(msym); 1872 msym->s_kind = SK_MEMBER; 1873 msym->s_scl = STRUCT_MEMBER; 1874 1875 struct_or_union *sou = expr_zero_alloc(sizeof(*sou), 1876 "struct_or_union"); 1877 sou->sou_tag = expr_zero_alloc(sizeof(*sou->sou_tag), "sym"); 1878 sou->sou_tag->s_name = unnamed; 1879 1880 msym->u.s_member.sm_containing_type = sou; 1881 /* 1882 * The member sm_offset_in_bits is not needed here since this symbol 1883 * can only be used for error reporting. 1884 */ 1885 } 1886 1887 /* 1888 * Returns a symbol which has the same name as 'msym' and is a member of the 1889 * struct or union specified by 'tn'. 1890 */ 1891 static sym_t * 1892 struct_or_union_member(tnode_t *tn, op_t op, sym_t *msym) 1893 { 1894 1895 /* Determine the tag type of which msym is expected to be a member. */ 1896 const type_t *tp = NULL; 1897 if (op == POINT && is_struct_or_union(tn->tn_type->t_tspec)) 1898 tp = tn->tn_type; 1899 if (op == ARROW && tn->tn_type->t_tspec == PTR 1900 && is_struct_or_union(tn->tn_type->t_subt->t_tspec)) 1901 tp = tn->tn_type->t_subt; 1902 struct_or_union *sou = tp != NULL ? tp->t_sou : NULL; 1903 1904 if (sou != NULL) { 1905 sym_t *nested_mem = find_member(sou, msym->s_name); 1906 if (nested_mem != NULL) 1907 return nested_mem; 1908 } 1909 1910 if (msym->s_scl == NO_SCL) { 1911 remove_unknown_member(tn, msym); 1912 return msym; 1913 } 1914 1915 bool eq = all_members_compatible(msym); 1916 1917 /* 1918 * Now handle the case in which the left operand refers really to a 1919 * struct/union, but the right operand is not member of it. 1920 */ 1921 if (sou != NULL) { 1922 if (eq && !allow_c90) { 1923 /* illegal use of member '%s' */ 1924 warning(102, msym->s_name); 1925 } else { 1926 /* illegal use of member '%s' */ 1927 error(102, msym->s_name); 1928 } 1929 return msym; 1930 } 1931 1932 if (eq) { 1933 if (op == POINT) { 1934 if (!allow_c90) { 1935 /* left operand of '.' must be struct ... */ 1936 warning(103, type_name(tn->tn_type)); 1937 } else { 1938 /* left operand of '.' must be struct ... */ 1939 error(103, type_name(tn->tn_type)); 1940 } 1941 } else { 1942 if (!allow_c90 && tn->tn_type->t_tspec == PTR) { 1943 /* left operand of '->' must be pointer ... */ 1944 warning(104, type_name(tn->tn_type)); 1945 } else { 1946 /* left operand of '->' must be pointer ... */ 1947 error(104, type_name(tn->tn_type)); 1948 } 1949 } 1950 } else { 1951 if (!allow_c90) { 1952 /* non-unique member requires struct/union %s */ 1953 error(105, op == POINT ? "object" : "pointer"); 1954 } else { 1955 /* unacceptable operand of '%s' */ 1956 error(111, op_name(op)); 1957 } 1958 } 1959 1960 return msym; 1961 } 1962 1963 tnode_t * 1964 build_member_access(tnode_t *ln, op_t op, bool sys, sbuf_t *member) 1965 { 1966 sym_t *msym; 1967 1968 if (ln == NULL) 1969 return NULL; 1970 1971 if (op == ARROW) { 1972 /* must do this before struct_or_union_member is called */ 1973 ln = cconv(ln); 1974 } 1975 msym = struct_or_union_member(ln, op, getsym(member)); 1976 return build_binary(ln, op, sys, build_name(msym, false)); 1977 } 1978 1979 /* 1980 * Perform class conversions. 1981 * 1982 * Arrays of type T are converted into pointers to type T. 1983 * Functions are converted to pointers to functions. 1984 * Lvalues are converted to rvalues. 1985 * 1986 * C99 6.3 "Conversions" 1987 * C99 6.3.2 "Other operands" 1988 * C99 6.3.2.1 "Lvalues, arrays, and function designators" 1989 */ 1990 tnode_t * 1991 cconv(tnode_t *tn) 1992 { 1993 if (tn->tn_type->t_tspec == ARRAY) { 1994 if (!tn->tn_lvalue) { 1995 /* XXX print correct operator */ 1996 /* %soperand of '%s' must be lvalue */ 1997 gnuism(114, "", op_name(ADDR)); 1998 } 1999 tn = build_op(ADDR, tn->tn_sys, 2000 expr_derive_type(tn->tn_type->t_subt, PTR), tn, NULL); 2001 } 2002 2003 if (tn->tn_type->t_tspec == FUNC) 2004 tn = build_address(tn->tn_sys, tn, true); 2005 2006 if (tn->tn_lvalue) { 2007 type_t *tp = expr_dup_type(tn->tn_type); 2008 /* C99 6.3.2.1p2 sentence 2 says to remove the qualifiers. */ 2009 tp->t_const = tp->t_volatile = false; 2010 tn = build_op(LOAD, tn->tn_sys, tp, tn, NULL); 2011 } 2012 2013 return tn; 2014 } 2015 2016 const tnode_t * 2017 before_conversion(const tnode_t *tn) 2018 { 2019 while (tn->tn_op == CVT && !tn->tn_cast) 2020 tn = tn->tn_left; 2021 return tn; 2022 } 2023 2024 /* 2025 * Most errors required by C90 are reported in struct_or_union_member(). 2026 * Here we only check for totally wrong things. 2027 */ 2028 static bool 2029 typeok_point(const tnode_t *ln, const type_t *ltp, tspec_t lt) 2030 { 2031 if (is_struct_or_union(lt)) 2032 return true; 2033 2034 if (lt == FUNC || lt == VOID || ltp->t_bitfield) 2035 goto wrong; 2036 2037 /* 2038 * Some C dialects from before C90 tolerated any lvalue on the 2039 * left-hand side of the '.' operator, allowing things like 'char 2040 * st[100]; st.st_mtime', assuming that the member 'st_mtime' only 2041 * occurred in a single struct; see typeok_arrow. 2042 */ 2043 if (ln->tn_lvalue) 2044 return true; 2045 2046 wrong: 2047 /* With allow_c90 we already got an error */ 2048 if (!allow_c90) 2049 /* unacceptable operand of '%s' */ 2050 error(111, op_name(POINT)); 2051 2052 return false; 2053 } 2054 2055 static bool 2056 typeok_arrow(tspec_t lt) 2057 { 2058 /* 2059 * C1978 Appendix A 14.1 says: <quote>In fact, any lvalue is allowed 2060 * before '.', and that lvalue is then assumed to have the form of the 2061 * structure of which the name of the right is a member. [...] Such 2062 * constructions are non-portable.</quote> 2063 */ 2064 if (lt == PTR || (!allow_c90 && is_integer(lt))) 2065 return true; 2066 2067 /* With allow_c90 we already got an error */ 2068 if (!allow_c90) 2069 /* unacceptable operand of '%s' */ 2070 error(111, op_name(ARROW)); 2071 return false; 2072 } 2073 2074 static bool 2075 typeok_incdec(op_t op, const tnode_t *tn, const type_t *tp) 2076 { 2077 /* operand has scalar type (checked in typeok) */ 2078 if (!tn->tn_lvalue) { 2079 if (tn->tn_op == CVT && tn->tn_cast && 2080 tn->tn_left->tn_op == LOAD) { 2081 /* a cast does not yield an lvalue */ 2082 error(163); 2083 } 2084 /* %soperand of '%s' must be lvalue */ 2085 error(114, "", op_name(op)); 2086 return false; 2087 } 2088 if (tp->t_const && allow_c90) { 2089 /* %soperand of '%s' must be modifiable lvalue */ 2090 warning(115, "", op_name(op)); 2091 } 2092 return true; 2093 } 2094 2095 static bool 2096 typeok_address(op_t op, const tnode_t *tn, const type_t *tp, tspec_t t) 2097 { 2098 if (t == ARRAY || t == FUNC) { 2099 /* ok, a warning comes later (in build_address()) */ 2100 } else if (!tn->tn_lvalue) { 2101 if (tn->tn_op == CVT && tn->tn_cast && 2102 tn->tn_left->tn_op == LOAD) { 2103 /* a cast does not yield an lvalue */ 2104 error(163); 2105 } 2106 /* %soperand of '%s' must be lvalue */ 2107 error(114, "", op_name(op)); 2108 return false; 2109 } else if (is_scalar(t)) { 2110 if (tp->t_bitfield) { 2111 /* cannot take address of bit-field */ 2112 error(112); 2113 return false; 2114 } 2115 } else if (t != STRUCT && t != UNION) { 2116 /* unacceptable operand of '%s' */ 2117 error(111, op_name(op)); 2118 return false; 2119 } 2120 if (tn->tn_op == NAME && tn->tn_sym->s_register) { 2121 /* cannot take address of register '%s' */ 2122 error(113, tn->tn_sym->s_name); 2123 return false; 2124 } 2125 return true; 2126 } 2127 2128 static bool 2129 typeok_indir(const type_t *tp, tspec_t t) 2130 { 2131 2132 if (t != PTR) { 2133 /* cannot dereference non-pointer type '%s' */ 2134 error(96, type_name(tp)); 2135 return false; 2136 } 2137 return true; 2138 } 2139 2140 static void 2141 warn_incompatible_types(op_t op, 2142 const type_t *ltp, tspec_t lt, 2143 const type_t *rtp, tspec_t rt) 2144 { 2145 bool binary = modtab[op].m_binary; 2146 2147 if (lt == VOID || (binary && rt == VOID)) { 2148 /* void type illegal in expression */ 2149 error(109); 2150 } else if (op == ASSIGN) { 2151 /* cannot assign to '%s' from '%s' */ 2152 error(171, type_name(ltp), type_name(rtp)); 2153 } else if (binary) { 2154 /* operands of '%s' have incompatible types '%s' and '%s' */ 2155 error(107, op_name(op), type_name(ltp), type_name(rtp)); 2156 } else { 2157 lint_assert(rt == NO_TSPEC); 2158 /* operand of '%s' has invalid type '%s' */ 2159 error(108, op_name(op), type_name(ltp)); 2160 } 2161 } 2162 2163 static bool 2164 typeok_plus(op_t op, 2165 const type_t *ltp, tspec_t lt, 2166 const type_t *rtp, tspec_t rt) 2167 { 2168 /* operands have scalar types (checked in typeok) */ 2169 if ((lt == PTR && !is_integer(rt)) || (rt == PTR && !is_integer(lt))) { 2170 warn_incompatible_types(op, ltp, lt, rtp, rt); 2171 return false; 2172 } 2173 return true; 2174 } 2175 2176 static bool 2177 typeok_minus(op_t op, 2178 const type_t *ltp, tspec_t lt, 2179 const type_t *rtp, tspec_t rt) 2180 { 2181 /* operands have scalar types (checked in typeok) */ 2182 if ((lt == PTR && rt != PTR && !is_integer(rt)) || 2183 (lt != PTR && rt == PTR)) { 2184 warn_incompatible_types(op, ltp, lt, rtp, rt); 2185 return false; 2186 } 2187 if (lt == PTR && rt == PTR && 2188 !types_compatible(ltp->t_subt, rtp->t_subt, true, false, NULL)) { 2189 /* illegal pointer subtraction */ 2190 error(116); 2191 } 2192 return true; 2193 } 2194 2195 static void 2196 typeok_shr(op_t op, 2197 const tnode_t *ln, tspec_t lt, 2198 const tnode_t *rn, tspec_t rt) 2199 { 2200 tspec_t olt = before_conversion(ln)->tn_type->t_tspec; 2201 tspec_t ort = before_conversion(rn)->tn_type->t_tspec; 2202 2203 /* operands have integer types (checked in typeok) */ 2204 if (pflag && !is_uinteger(olt)) { 2205 integer_constraints lc = ic_expr(ln); 2206 if (!ic_maybe_signed(ln->tn_type, &lc)) 2207 return; 2208 2209 if (ln->tn_op != CON) { 2210 /* bitwise '%s' on signed value possibly nonportable */ 2211 warning(117, op_name(op)); 2212 } else if (ln->tn_val.u.integer < 0) { 2213 /* bitwise '%s' on signed value nonportable */ 2214 warning(120, op_name(op)); 2215 } 2216 } else if (allow_trad && allow_c90 && 2217 !is_uinteger(olt) && is_uinteger(ort)) { 2218 /* The left operand would become unsigned in traditional C. */ 2219 if (hflag && (ln->tn_op != CON || ln->tn_val.u.integer < 0)) { 2220 /* semantics of '%s' change in C90; use ... */ 2221 warning(118, op_name(op)); 2222 } 2223 } else if (allow_trad && allow_c90 && 2224 !is_uinteger(olt) && !is_uinteger(ort) && 2225 portable_rank_cmp(lt, rt) < 0) { 2226 /* 2227 * In traditional C, the left operand would be extended 2228 * (possibly sign-extended) and then shifted. 2229 */ 2230 if (hflag && (ln->tn_op != CON || ln->tn_val.u.integer < 0)) { 2231 /* semantics of '%s' change in C90; use ... */ 2232 warning(118, op_name(op)); 2233 } 2234 } 2235 } 2236 2237 static void 2238 typeok_shl(op_t op, tspec_t lt, tspec_t rt) 2239 { 2240 /* 2241 * C90 does not perform balancing for shift operations, but traditional 2242 * C does. If the width of the right operand is greater than the width 2243 * of the left operand, then in traditional C the left operand would be 2244 * extended to the width of the right operand. For SHL this may result 2245 * in different results. 2246 */ 2247 if (portable_rank_cmp(lt, rt) < 0) { 2248 /* 2249 * XXX If both operands are constant, make sure that there is 2250 * really a difference between C90 and traditional C. 2251 */ 2252 if (hflag && allow_trad && allow_c90) 2253 /* semantics of '%s' change in C90; use ... */ 2254 warning(118, op_name(op)); 2255 } 2256 } 2257 2258 static void 2259 typeok_shift(const type_t *ltp, tspec_t lt, const tnode_t *rn, tspec_t rt) 2260 { 2261 if (rn->tn_op != CON) 2262 return; 2263 2264 if (!is_uinteger(rt) && rn->tn_val.u.integer < 0) { 2265 /* negative shift */ 2266 warning(121); 2267 } else if ((uint64_t)rn->tn_val.u.integer == size_in_bits(lt)) { 2268 /* shift amount %u equals bit-size of '%s' */ 2269 warning(267, (unsigned)rn->tn_val.u.integer, type_name(ltp)); 2270 } else if ((uint64_t)rn->tn_val.u.integer > size_in_bits(lt)) { 2271 /* shift amount %llu is greater than bit-size %llu of '%s' */ 2272 warning(122, (unsigned long long)rn->tn_val.u.integer, 2273 (unsigned long long)size_in_bits(lt), 2274 tspec_name(lt)); 2275 } 2276 } 2277 2278 static bool 2279 is_typeok_eq(const tnode_t *ln, tspec_t lt, const tnode_t *rn, tspec_t rt) 2280 { 2281 if (lt == PTR && is_null_pointer(rn)) 2282 return true; 2283 if (rt == PTR && is_null_pointer(ln)) 2284 return true; 2285 return false; 2286 } 2287 2288 static void 2289 warn_incompatible_pointers(op_t op, const type_t *ltp, const type_t *rtp) 2290 { 2291 lint_assert(ltp->t_tspec == PTR); 2292 lint_assert(rtp->t_tspec == PTR); 2293 2294 tspec_t lt = ltp->t_subt->t_tspec; 2295 tspec_t rt = rtp->t_subt->t_tspec; 2296 2297 if (is_struct_or_union(lt) && is_struct_or_union(rt)) { 2298 if (op == RETURN) { 2299 /* illegal structure pointer combination */ 2300 warning(244); 2301 } else { 2302 /* incompatible structure pointers: '%s' '%s' '%s' */ 2303 warning(245, type_name(ltp), 2304 op_name(op), type_name(rtp)); 2305 } 2306 } else { 2307 if (op == RETURN) { 2308 /* illegal combination of '%s' and '%s' */ 2309 warning(184, type_name(ltp), type_name(rtp)); 2310 } else { 2311 /* illegal combination of '%s' and '%s', op '%s' */ 2312 warning(124, 2313 type_name(ltp), type_name(rtp), op_name(op)); 2314 } 2315 } 2316 } 2317 2318 static void 2319 check_pointer_comparison(op_t op, const tnode_t *ln, const tnode_t *rn) 2320 { 2321 type_t *ltp = ln->tn_type, *rtp = rn->tn_type; 2322 tspec_t lst = ltp->t_subt->t_tspec, rst = rtp->t_subt->t_tspec; 2323 2324 if (lst == VOID || rst == VOID) { 2325 /* TODO: C99 behaves like C90 here. */ 2326 if (!allow_trad && !allow_c99 && 2327 (lst == FUNC || rst == FUNC)) { 2328 /* (void *)0 is already handled in typeok() */ 2329 const char *lsts, *rsts; 2330 *(lst == FUNC ? &lsts : &rsts) = "function pointer"; 2331 *(lst == VOID ? &lsts : &rsts) = "'void *'"; 2332 /* C90 or later forbid comparison of %s with %s */ 2333 warning(274, lsts, rsts); 2334 } 2335 return; 2336 } 2337 2338 if (!types_compatible(ltp->t_subt, rtp->t_subt, true, false, NULL)) { 2339 warn_incompatible_pointers(op, ltp, rtp); 2340 return; 2341 } 2342 2343 if (lst == FUNC && rst == FUNC) { 2344 /* TODO: C99 behaves like C90 here, see C99 6.5.8p2. */ 2345 if (!allow_trad && !allow_c99 && op != EQ && op != NE) 2346 /* pointers to functions can only be compared ... */ 2347 warning(125); 2348 } 2349 } 2350 2351 static bool 2352 typeok_compare(op_t op, 2353 const tnode_t *ln, const type_t *ltp, tspec_t lt, 2354 const tnode_t *rn, const type_t *rtp, tspec_t rt) 2355 { 2356 if (lt == PTR && rt == PTR) { 2357 check_pointer_comparison(op, ln, rn); 2358 return true; 2359 } 2360 2361 if (lt != PTR && rt != PTR) 2362 return true; 2363 2364 if (!is_integer(lt) && !is_integer(rt)) { 2365 warn_incompatible_types(op, ltp, lt, rtp, rt); 2366 return false; 2367 } 2368 2369 const char *lx = lt == PTR ? "pointer" : "integer"; 2370 const char *rx = rt == PTR ? "pointer" : "integer"; 2371 /* illegal combination of %s '%s' and %s '%s', op '%s' */ 2372 warning(123, lx, type_name(ltp), rx, type_name(rtp), op_name(op)); 2373 return true; 2374 } 2375 2376 static bool 2377 typeok_quest(tspec_t lt, const tnode_t *rn) 2378 { 2379 if (!is_scalar(lt)) { 2380 /* first operand of '?' must have scalar type */ 2381 error(170); 2382 return false; 2383 } 2384 lint_assert(before_conversion(rn)->tn_op == COLON); 2385 return true; 2386 } 2387 2388 static void 2389 typeok_colon_pointer(const type_t *ltp, const type_t *rtp) 2390 { 2391 type_t *lstp = ltp->t_subt; 2392 type_t *rstp = rtp->t_subt; 2393 tspec_t lst = lstp->t_tspec; 2394 tspec_t rst = rstp->t_tspec; 2395 2396 if ((lst == VOID && rst == FUNC) || (lst == FUNC && rst == VOID)) { 2397 /* (void *)0 is handled in typeok_colon */ 2398 /* TODO: C99 behaves like C90 here. */ 2399 if (!allow_trad && !allow_c99) 2400 /* conversion of %s to %s requires a cast, op %s */ 2401 warning(305, "function pointer", "'void *'", 2402 op_name(COLON)); 2403 return; 2404 } 2405 2406 if (pointer_types_are_compatible(lstp, rstp, true)) 2407 return; 2408 if (!types_compatible(lstp, rstp, true, false, NULL)) 2409 warn_incompatible_pointers(COLON, ltp, rtp); 2410 } 2411 2412 static bool 2413 typeok_colon(const tnode_t *ln, const type_t *ltp, tspec_t lt, 2414 const tnode_t *rn, const type_t *rtp, tspec_t rt) 2415 { 2416 2417 if (is_arithmetic(lt) && is_arithmetic(rt)) 2418 return true; 2419 if (lt == BOOL && rt == BOOL) 2420 return true; 2421 2422 if (lt == STRUCT && rt == STRUCT && ltp->t_sou == rtp->t_sou) 2423 return true; 2424 if (lt == UNION && rt == UNION && ltp->t_sou == rtp->t_sou) 2425 return true; 2426 2427 if (lt == PTR && is_null_pointer(rn)) 2428 return true; 2429 if (rt == PTR && is_null_pointer(ln)) 2430 return true; 2431 2432 if ((lt == PTR && is_integer(rt)) || (is_integer(lt) && rt == PTR)) { 2433 const char *lx = lt == PTR ? "pointer" : "integer"; 2434 const char *rx = rt == PTR ? "pointer" : "integer"; 2435 /* illegal combination of %s '%s' and %s '%s', op '%s' */ 2436 warning(123, lx, type_name(ltp), 2437 rx, type_name(rtp), op_name(COLON)); 2438 return true; 2439 } 2440 2441 if (lt == VOID || rt == VOID) { 2442 if (lt != VOID || rt != VOID) 2443 /* incompatible types '%s' and '%s' in conditional */ 2444 warning(126, type_name(ltp), type_name(rtp)); 2445 return true; 2446 } 2447 2448 if (lt == PTR && rt == PTR) { 2449 typeok_colon_pointer(ltp, rtp); 2450 return true; 2451 } 2452 2453 /* incompatible types '%s' and '%s' in conditional */ 2454 error(126, type_name(ltp), type_name(rtp)); 2455 return false; 2456 } 2457 2458 static bool 2459 has_constant_member(const type_t *tp) 2460 { 2461 lint_assert(is_struct_or_union(tp->t_tspec)); 2462 2463 for (sym_t *m = tp->t_sou->sou_first_member; 2464 m != NULL; m = m->s_next) { 2465 const type_t *mtp = m->s_type; 2466 if (mtp->t_const) 2467 return true; 2468 if (is_struct_or_union(mtp->t_tspec) && 2469 has_constant_member(mtp)) 2470 return true; 2471 } 2472 return false; 2473 } 2474 2475 static bool 2476 typeok_assign(op_t op, const tnode_t *ln, const type_t *ltp, tspec_t lt) 2477 { 2478 if (op == RETURN || op == INIT || op == FARG) 2479 return true; 2480 2481 if (!ln->tn_lvalue) { 2482 if (ln->tn_op == CVT && ln->tn_cast && 2483 ln->tn_left->tn_op == LOAD) { 2484 /* a cast does not yield an lvalue */ 2485 error(163); 2486 } 2487 /* %soperand of '%s' must be lvalue */ 2488 error(114, "left ", op_name(op)); 2489 return false; 2490 } else if (ltp->t_const 2491 || (is_struct_or_union(lt) && has_constant_member(ltp))) { 2492 if (allow_c90) 2493 /* %soperand of '%s' must be modifiable lvalue */ 2494 warning(115, "left ", op_name(op)); 2495 } 2496 return true; 2497 } 2498 2499 static bool 2500 typeok_scalar(op_t op, const mod_t *mp, 2501 const type_t *ltp, tspec_t lt, 2502 const type_t *rtp, tspec_t rt) 2503 { 2504 if (mp->m_takes_bool && lt == BOOL && rt == BOOL) 2505 return true; 2506 if (mp->m_requires_integer) { 2507 if (!is_integer(lt) || (mp->m_binary && !is_integer(rt))) { 2508 warn_incompatible_types(op, ltp, lt, rtp, rt); 2509 return false; 2510 } 2511 } else if (mp->m_requires_integer_or_complex) { 2512 if ((!is_integer(lt) && !is_complex(lt)) || 2513 (mp->m_binary && (!is_integer(rt) && !is_complex(rt)))) { 2514 warn_incompatible_types(op, ltp, lt, rtp, rt); 2515 return false; 2516 } 2517 } else if (mp->m_requires_scalar) { 2518 if (!is_scalar(lt) || (mp->m_binary && !is_scalar(rt))) { 2519 warn_incompatible_types(op, ltp, lt, rtp, rt); 2520 return false; 2521 } 2522 } else if (mp->m_requires_arith) { 2523 if (!is_arithmetic(lt) || 2524 (mp->m_binary && !is_arithmetic(rt))) { 2525 warn_incompatible_types(op, ltp, lt, rtp, rt); 2526 return false; 2527 } 2528 } 2529 return true; 2530 } 2531 2532 static void 2533 check_assign_void_pointer(op_t op, int arg, 2534 tspec_t lt, tspec_t lst, 2535 tspec_t rt, tspec_t rst) 2536 { 2537 2538 if (!(lt == PTR && rt == PTR && (lst == VOID || rst == VOID))) 2539 return; 2540 /* two pointers, at least one pointer to void */ 2541 2542 /* TODO: C99 behaves like C90 here. */ 2543 if (!(!allow_trad && !allow_c99 && (lst == FUNC || rst == FUNC))) 2544 return; 2545 /* comb. of ptr to func and ptr to void */ 2546 2547 const char *lts, *rts; 2548 *(lst == FUNC ? <s : &rts) = "function pointer"; 2549 *(lst == VOID ? <s : &rts) = "'void *'"; 2550 2551 switch (op) { 2552 case INIT: 2553 case RETURN: 2554 /* conversion of %s to %s requires a cast */ 2555 warning(303, rts, lts); 2556 break; 2557 case FARG: 2558 /* conversion of %s to %s requires a cast, arg #%d */ 2559 warning(304, rts, lts, arg); 2560 break; 2561 default: 2562 /* conversion of %s to %s requires a cast, op %s */ 2563 warning(305, rts, lts, op_name(op)); 2564 break; 2565 } 2566 } 2567 2568 static bool 2569 is_direct_function_call(const tnode_t *tn, const char **out_name) 2570 { 2571 2572 if (!(tn->tn_op == CALL && 2573 tn->tn_left->tn_op == ADDR && 2574 tn->tn_left->tn_left->tn_op == NAME)) 2575 return false; 2576 2577 *out_name = tn->tn_left->tn_left->tn_sym->s_name; 2578 return true; 2579 } 2580 2581 static bool 2582 is_unconst_function(const char *name) 2583 { 2584 2585 return strcmp(name, "memchr") == 0 || 2586 strcmp(name, "strchr") == 0 || 2587 strcmp(name, "strpbrk") == 0 || 2588 strcmp(name, "strrchr") == 0 || 2589 strcmp(name, "strstr") == 0; 2590 } 2591 2592 static bool 2593 is_const_char_pointer(const tnode_t *tn) 2594 { 2595 /* 2596 * For traditional reasons, C99 6.4.5p5 defines that string literals 2597 * have type 'char[]'. They are often implicitly converted to 'char 2598 * *', for example when they are passed as function arguments. 2599 * 2600 * C99 6.4.5p6 further defines that modifying a string that is 2601 * constructed from a string literal invokes undefined behavior. 2602 * 2603 * Out of these reasons, string literals are treated as 'effectively 2604 * const' here. 2605 */ 2606 if (tn->tn_op == CVT && 2607 tn->tn_left->tn_op == ADDR && 2608 tn->tn_left->tn_left->tn_op == STRING) 2609 return true; 2610 2611 const type_t *tp = before_conversion(tn)->tn_type; 2612 return tp->t_tspec == PTR && 2613 tp->t_subt->t_tspec == CHAR && 2614 tp->t_subt->t_const; 2615 } 2616 2617 static bool 2618 is_first_arg_const_char_pointer(const tnode_t *tn) 2619 { 2620 lint_assert(has_operands(tn)); 2621 const tnode_t *an = tn->tn_right; 2622 if (an == NULL) 2623 return false; 2624 2625 while (tn_ck_right(an) != NULL) 2626 an = an->tn_right; 2627 return is_const_char_pointer(an->tn_left); 2628 } 2629 2630 static bool 2631 is_const_pointer(const tnode_t *tn) 2632 { 2633 const type_t *tp = before_conversion(tn)->tn_type; 2634 return tp->t_tspec == PTR && tp->t_subt->t_const; 2635 } 2636 2637 static bool 2638 is_second_arg_const_pointer(const tnode_t *tn) 2639 { 2640 const tnode_t *an = tn_ck_right(tn); 2641 if (an == NULL || tn_ck_right(an) == NULL) 2642 return false; 2643 2644 while (tn_ck_right(an->tn_right) != NULL) 2645 an = an->tn_right; 2646 return is_const_pointer(an->tn_left); 2647 } 2648 2649 static void 2650 check_unconst_function(const type_t *lstp, const tnode_t *rn) 2651 { 2652 const char *function_name; 2653 2654 if (lstp->t_tspec == CHAR && !lstp->t_const && 2655 is_direct_function_call(rn, &function_name) && 2656 is_unconst_function(function_name) && 2657 is_first_arg_const_char_pointer(rn)) { 2658 /* call to '%s' effectively discards 'const' from argument */ 2659 warning(346, function_name); 2660 } 2661 2662 if (!lstp->t_const && 2663 is_direct_function_call(rn, &function_name) && 2664 strcmp(function_name, "bsearch") == 0 && 2665 is_second_arg_const_pointer(rn)) { 2666 /* call to '%s' effectively discards 'const' from argument */ 2667 warning(346, function_name); 2668 } 2669 } 2670 2671 static bool 2672 check_assign_void_pointer_compat(op_t op, int arg, 2673 const type_t *ltp, tspec_t lt, 2674 const type_t *lstp, tspec_t lst, 2675 const tnode_t *rn, 2676 const type_t *rtp, tspec_t rt, 2677 const type_t *rstp, tspec_t rst) 2678 { 2679 if (!(lt == PTR && rt == PTR && (lst == VOID || rst == VOID || 2680 types_compatible(lstp, rstp, 2681 true, false, NULL)))) 2682 return false; 2683 2684 /* compatible pointer types (qualifiers ignored) */ 2685 if (allow_c90 && 2686 ((!lstp->t_const && rstp->t_const) || 2687 (!lstp->t_volatile && rstp->t_volatile))) { 2688 /* left side has not all qualifiers of right */ 2689 switch (op) { 2690 case INIT: 2691 case RETURN: 2692 /* incompatible pointer types to '%s' and '%s' */ 2693 warning(182, type_name(lstp), type_name(rstp)); 2694 break; 2695 case FARG: 2696 /* converting '%s' to incompatible '%s' ... */ 2697 warning(153, 2698 type_name(rtp), type_name(ltp), arg); 2699 break; 2700 default: 2701 /* operands of '%s' have incompatible pointer ... */ 2702 warning(128, op_name(op), 2703 type_name(lstp), type_name(rstp)); 2704 break; 2705 } 2706 } 2707 2708 if (allow_c90) 2709 check_unconst_function(lstp, rn); 2710 2711 return true; 2712 } 2713 2714 static bool 2715 check_assign_pointer_integer(op_t op, int arg, 2716 const type_t *ltp, tspec_t lt, 2717 const type_t *rtp, tspec_t rt) 2718 { 2719 2720 if (!((lt == PTR && is_integer(rt)) || (is_integer(lt) && rt == PTR))) 2721 return false; 2722 2723 const char *lx = lt == PTR ? "pointer" : "integer"; 2724 const char *rx = rt == PTR ? "pointer" : "integer"; 2725 2726 switch (op) { 2727 case INIT: 2728 case RETURN: 2729 /* illegal combination of %s '%s' and %s '%s' */ 2730 warning(183, lx, type_name(ltp), rx, type_name(rtp)); 2731 break; 2732 case FARG: 2733 /* illegal combination of %s '%s' and %s '%s', arg #%d */ 2734 warning(154, 2735 lx, type_name(ltp), rx, type_name(rtp), arg); 2736 break; 2737 default: 2738 /* illegal combination of %s '%s' and %s '%s', op '%s' */ 2739 warning(123, 2740 lx, type_name(ltp), rx, type_name(rtp), op_name(op)); 2741 break; 2742 } 2743 return true; 2744 } 2745 2746 static bool 2747 check_assign_pointer(op_t op, int arg, 2748 const type_t *ltp, tspec_t lt, 2749 const type_t *rtp, tspec_t rt) 2750 { 2751 if (!(lt == PTR && rt == PTR)) 2752 return false; 2753 2754 if (op == FARG) 2755 /* converting '%s' to incompatible '%s' for ... */ 2756 warning(153, type_name(rtp), type_name(ltp), arg); 2757 else 2758 warn_incompatible_pointers(op, ltp, rtp); 2759 return true; 2760 } 2761 2762 static void 2763 warn_assign(op_t op, int arg, 2764 const type_t *ltp, tspec_t lt, 2765 const type_t *rtp, tspec_t rt) 2766 { 2767 switch (op) { 2768 case INIT: 2769 /* cannot initialize '%s' from '%s' */ 2770 error(185, type_name(ltp), type_name(rtp)); 2771 break; 2772 case RETURN: 2773 /* function has return type '%s' but returns '%s' */ 2774 error(211, type_name(ltp), type_name(rtp)); 2775 break; 2776 case FARG: 2777 /* passing '%s' to incompatible '%s', arg #%d */ 2778 warning(155, type_name(rtp), type_name(ltp), arg); 2779 break; 2780 default: 2781 warn_incompatible_types(op, ltp, lt, rtp, rt); 2782 break; 2783 } 2784 } 2785 2786 /* 2787 * Checks type compatibility for ASSIGN, INIT, FARG and RETURN 2788 * and prints warnings/errors if necessary. 2789 * Returns whether the types are (almost) compatible. 2790 */ 2791 static bool 2792 check_assign_types_compatible(op_t op, int arg, 2793 const tnode_t *ln, const tnode_t *rn) 2794 { 2795 tspec_t lt, rt, lst = NO_TSPEC, rst = NO_TSPEC; 2796 type_t *ltp, *rtp, *lstp = NULL, *rstp = NULL; 2797 2798 if ((lt = (ltp = ln->tn_type)->t_tspec) == PTR) 2799 lst = (lstp = ltp->t_subt)->t_tspec; 2800 if ((rt = (rtp = rn->tn_type)->t_tspec) == PTR) 2801 rst = (rstp = rtp->t_subt)->t_tspec; 2802 2803 if (lt == BOOL && is_scalar(rt)) /* C99 6.3.1.2 */ 2804 return true; 2805 2806 if (is_arithmetic(lt) && (is_arithmetic(rt) || rt == BOOL)) 2807 return true; 2808 2809 if (is_struct_or_union(lt) && is_struct_or_union(rt)) 2810 return ltp->t_sou == rtp->t_sou; 2811 2812 if (lt == PTR && is_null_pointer(rn)) { 2813 if (is_integer(rn->tn_type->t_tspec)) 2814 /* implicit conversion from integer 0 to pointer ... */ 2815 query_message(15, type_name(ltp)); 2816 return true; 2817 } 2818 2819 check_assign_void_pointer(op, arg, lt, lst, rt, rst); 2820 2821 if (check_assign_void_pointer_compat(op, arg, 2822 ltp, lt, lstp, lst, rn, rtp, rt, rstp, rst)) 2823 return true; 2824 2825 if (check_assign_pointer_integer(op, arg, ltp, lt, rtp, rt)) 2826 return true; 2827 2828 if (check_assign_pointer(op, arg, ltp, lt, rtp, rt)) 2829 return true; 2830 2831 warn_assign(op, arg, ltp, lt, rtp, rt); 2832 return false; 2833 } 2834 2835 static bool 2836 has_side_effect(const tnode_t *tn) /* NOLINT(misc-no-recursion) */ 2837 { 2838 op_t op = tn->tn_op; 2839 2840 if (modtab[op].m_has_side_effect) 2841 return true; 2842 2843 if (op == CVT && tn->tn_type->t_tspec == VOID) 2844 return has_side_effect(tn->tn_left); 2845 2846 /* XXX: Why not has_side_effect(tn->tn_left) as well? */ 2847 if (op == LOGAND || op == LOGOR) 2848 return has_side_effect(tn->tn_right); 2849 2850 /* XXX: Why not has_side_effect(tn->tn_left) as well? */ 2851 if (op == QUEST) 2852 return has_side_effect(tn->tn_right); 2853 2854 if (op == COLON || op == COMMA) { 2855 return has_side_effect(tn->tn_left) || 2856 has_side_effect(tn->tn_right); 2857 } 2858 2859 return false; 2860 } 2861 2862 static bool 2863 is_void_cast(const tnode_t *tn) 2864 { 2865 2866 return tn->tn_op == CVT && tn->tn_cast && 2867 tn->tn_type->t_tspec == VOID; 2868 } 2869 2870 static bool 2871 is_local_symbol(const tnode_t *tn) 2872 { 2873 2874 return tn->tn_op == LOAD && 2875 tn->tn_left->tn_op == NAME && 2876 tn->tn_left->tn_sym->s_scl == AUTO; 2877 } 2878 2879 static bool 2880 is_int_constant_zero(const tnode_t *tn) 2881 { 2882 2883 return tn->tn_op == CON && 2884 tn->tn_type->t_tspec == INT && 2885 tn->tn_val.u.integer == 0; 2886 } 2887 2888 static void 2889 check_null_effect(const tnode_t *tn) 2890 { 2891 2892 if (hflag && 2893 !has_side_effect(tn) && 2894 !(is_void_cast(tn) && is_local_symbol(tn->tn_left)) && 2895 !(is_void_cast(tn) && is_int_constant_zero(tn->tn_left))) { 2896 /* expression has null effect */ 2897 warning(129); 2898 } 2899 } 2900 2901 /* 2902 * Check the types for specific operators and type combinations. 2903 * 2904 * At this point, the operands already conform to the type requirements of 2905 * the operator, such as being integer, floating or scalar. 2906 */ 2907 static bool 2908 typeok_op(op_t op, int arg, 2909 const tnode_t *ln, const type_t *ltp, tspec_t lt, 2910 const tnode_t *rn, const type_t *rtp, tspec_t rt) 2911 { 2912 switch (op) { 2913 case ARROW: 2914 return typeok_arrow(lt); 2915 case POINT: 2916 return typeok_point(ln, ltp, lt); 2917 case INCBEF: 2918 case DECBEF: 2919 case INCAFT: 2920 case DECAFT: 2921 return typeok_incdec(op, ln, ltp); 2922 case INDIR: 2923 return typeok_indir(ltp, lt); 2924 case ADDR: 2925 return typeok_address(op, ln, ltp, lt); 2926 case PLUS: 2927 return typeok_plus(op, ltp, lt, rtp, rt); 2928 case MINUS: 2929 return typeok_minus(op, ltp, lt, rtp, rt); 2930 case SHL: 2931 typeok_shl(op, lt, rt); 2932 goto shift; 2933 case SHR: 2934 typeok_shr(op, ln, lt, rn, rt); 2935 shift: 2936 typeok_shift(ltp, lt, rn, rt); 2937 break; 2938 case LT: 2939 case LE: 2940 case GT: 2941 case GE: 2942 compare: 2943 return typeok_compare(op, ln, ltp, lt, rn, rtp, rt); 2944 case EQ: 2945 case NE: 2946 if (is_typeok_eq(ln, lt, rn, rt)) 2947 break; 2948 goto compare; 2949 case QUEST: 2950 return typeok_quest(lt, rn); 2951 case COLON: 2952 return typeok_colon(ln, ltp, lt, rn, rtp, rt); 2953 case ASSIGN: 2954 case INIT: 2955 case FARG: 2956 case RETURN: 2957 if (!check_assign_types_compatible(op, arg, ln, rn)) 2958 return false; 2959 goto assign; 2960 case MULASS: 2961 case DIVASS: 2962 case MODASS: 2963 goto assign; 2964 case ADDASS: 2965 case SUBASS: 2966 if ((lt == PTR && !is_integer(rt)) || rt == PTR) { 2967 warn_incompatible_types(op, ltp, lt, rtp, rt); 2968 return false; 2969 } 2970 goto assign; 2971 case SHLASS: 2972 goto assign; 2973 case SHRASS: 2974 if (pflag && !is_uinteger(lt) && 2975 !(!allow_c90 && is_uinteger(rt))) { 2976 /* bitwise '%s' on signed value possibly nonportable */ 2977 warning(117, op_name(op)); 2978 } 2979 goto assign; 2980 case ANDASS: 2981 case XORASS: 2982 case ORASS: 2983 assign: 2984 return typeok_assign(op, ln, ltp, lt); 2985 case COMMA: 2986 if (!modtab[ln->tn_op].m_has_side_effect) 2987 check_null_effect(ln); 2988 break; 2989 default: 2990 break; 2991 } 2992 return true; 2993 } 2994 2995 static void 2996 check_bad_enum_operation(op_t op, const tnode_t *ln, const tnode_t *rn) 2997 { 2998 2999 if (!eflag) 3000 return; 3001 3002 /* Allow enum in array indices. */ 3003 if (op == PLUS && 3004 ((ln->tn_type->t_is_enum && rn->tn_type->t_tspec == PTR) || 3005 (rn->tn_type->t_is_enum && ln->tn_type->t_tspec == PTR))) { 3006 return; 3007 } 3008 3009 /* dubious operation '%s' on enum */ 3010 warning(241, op_name(op)); 3011 } 3012 3013 static void 3014 check_enum_type_mismatch(op_t op, int arg, const tnode_t *ln, const tnode_t *rn) 3015 { 3016 const mod_t *mp = &modtab[op]; 3017 3018 if (ln->tn_type->t_enum != rn->tn_type->t_enum) { 3019 switch (op) { 3020 case INIT: 3021 /* enum type mismatch between '%s' and '%s' in ... */ 3022 warning(210, 3023 type_name(ln->tn_type), type_name(rn->tn_type)); 3024 break; 3025 case FARG: 3026 /* function expects '%s', passing '%s' for arg #%d */ 3027 warning(156, 3028 type_name(ln->tn_type), type_name(rn->tn_type), 3029 arg); 3030 break; 3031 case RETURN: 3032 /* function has return type '%s' but returns '%s' */ 3033 warning(211, 3034 type_name(ln->tn_type), type_name(rn->tn_type)); 3035 break; 3036 default: 3037 /* enum type mismatch: '%s' '%s' '%s' */ 3038 warning(130, type_name(ln->tn_type), op_name(op), 3039 type_name(rn->tn_type)); 3040 break; 3041 } 3042 } else if (Pflag && eflag && mp->m_comparison && op != EQ && op != NE) 3043 /* operator '%s' assumes that '%s' is ordered */ 3044 warning(243, op_name(op), type_name(ln->tn_type)); 3045 } 3046 3047 static void 3048 check_enum_int_mismatch(op_t op, int arg, const tnode_t *ln, const tnode_t *rn) 3049 { 3050 3051 if (!eflag) 3052 return; 3053 3054 switch (op) { 3055 case INIT: 3056 /* 3057 * Initialization with 0 is allowed. Otherwise, all implicit 3058 * initializations would need to be warned upon as well. 3059 */ 3060 if (!rn->tn_type->t_is_enum && rn->tn_op == CON && 3061 is_integer(rn->tn_type->t_tspec) && 3062 rn->tn_val.u.integer == 0) { 3063 return; 3064 } 3065 /* initialization of '%s' with '%s' */ 3066 warning(277, type_name(ln->tn_type), type_name(rn->tn_type)); 3067 break; 3068 case FARG: 3069 /* combination of '%s' and '%s', arg #%d */ 3070 warning(278, 3071 type_name(ln->tn_type), type_name(rn->tn_type), arg); 3072 break; 3073 case RETURN: 3074 /* combination of '%s' and '%s' in return */ 3075 warning(279, type_name(ln->tn_type), type_name(rn->tn_type)); 3076 break; 3077 default: 3078 /* combination of '%s' and '%s', op '%s' */ 3079 warning(242, type_name(ln->tn_type), type_name(rn->tn_type), 3080 op_name(op)); 3081 break; 3082 } 3083 } 3084 3085 static void 3086 typeok_enum(op_t op, const mod_t *mp, int arg, 3087 const tnode_t *ln, const type_t *ltp, 3088 const tnode_t *rn, const type_t *rtp) 3089 { 3090 if (mp->m_bad_on_enum && 3091 (ltp->t_is_enum || (mp->m_binary && rtp->t_is_enum))) { 3092 check_bad_enum_operation(op, ln, rn); 3093 } else if (mp->m_valid_on_enum && 3094 (ltp->t_is_enum && rtp != NULL && rtp->t_is_enum)) { 3095 check_enum_type_mismatch(op, arg, ln, rn); 3096 } else if (mp->m_valid_on_enum && 3097 (ltp->t_is_enum || (rtp != NULL && rtp->t_is_enum))) { 3098 check_enum_int_mismatch(op, arg, ln, rn); 3099 } 3100 } 3101 3102 /* Perform most type checks. Return whether the types are ok. */ 3103 bool 3104 typeok(op_t op, int arg, const tnode_t *ln, const tnode_t *rn) 3105 { 3106 3107 const mod_t *mp = &modtab[op]; 3108 3109 type_t *ltp = ln->tn_type; 3110 tspec_t lt = ltp->t_tspec; 3111 3112 type_t *rtp = mp->m_binary ? rn->tn_type : NULL; 3113 tspec_t rt = mp->m_binary ? rtp->t_tspec : NO_TSPEC; 3114 3115 if (Tflag && !typeok_scalar_strict_bool(op, mp, arg, ln, rn)) 3116 return false; 3117 if (!typeok_scalar(op, mp, ltp, lt, rtp, rt)) 3118 return false; 3119 3120 if (!typeok_op(op, arg, ln, ltp, lt, rn, rtp, rt)) 3121 return false; 3122 3123 typeok_enum(op, mp, arg, ln, ltp, rn, rtp); 3124 return true; 3125 } 3126 3127 /* In traditional C, keep unsigned and promote FLOAT to DOUBLE. */ 3128 static tspec_t 3129 promote_trad(tspec_t t) 3130 { 3131 3132 if (t == UCHAR || t == USHORT) 3133 return UINT; 3134 if (t == CHAR || t == SCHAR || t == SHORT) 3135 return INT; 3136 if (t == FLOAT) 3137 return DOUBLE; 3138 if (t == ENUM) 3139 return INT; 3140 return t; 3141 } 3142 3143 /* 3144 * C99 6.3.1.1p2 requires for types with lower rank than int that "If an int 3145 * can represent all the values of the original type, the value is converted 3146 * to an int; otherwise it is converted to an unsigned int", and that "All 3147 * other types are unchanged by the integer promotions". 3148 */ 3149 static tspec_t 3150 promote_c90(const tnode_t *tn, tspec_t t, bool farg) 3151 { 3152 if (tn->tn_type->t_bitfield) { 3153 unsigned int width = tn->tn_type->t_bit_field_width; 3154 unsigned int int_width = size_in_bits(INT); 3155 // XXX: What about _Bool bit-fields, since C99? 3156 if (width < int_width) 3157 return INT; 3158 if (width == int_width) 3159 return is_uinteger(t) ? UINT : INT; 3160 return t; 3161 } 3162 3163 if (t == CHAR || t == SCHAR) 3164 return INT; 3165 if (t == UCHAR) 3166 return size_in_bits(CHAR) < size_in_bits(INT) ? INT : UINT; 3167 if (t == SHORT) 3168 return INT; 3169 if (t == USHORT) 3170 return size_in_bits(SHORT) < size_in_bits(INT) ? INT : UINT; 3171 if (t == ENUM) 3172 return INT; 3173 if (farg && t == FLOAT) 3174 return DOUBLE; 3175 return t; 3176 } 3177 3178 /* 3179 * Performs the "integer promotions" (C99 6.3.1.1p2), which convert small 3180 * integer types to either int or unsigned int. 3181 * 3182 * If allow_c90 is unset or the operand is a function argument with no type 3183 * information (no prototype or variable # of args), converts float to double. 3184 */ 3185 tnode_t * 3186 promote(op_t op, bool farg, tnode_t *tn) 3187 { 3188 3189 tspec_t ot = tn->tn_type->t_tspec; 3190 if (!is_arithmetic(ot)) 3191 return tn; 3192 3193 tspec_t nt = allow_c90 ? promote_c90(tn, ot, farg) : promote_trad(ot); 3194 if (nt == ot) 3195 return tn; 3196 3197 type_t *ntp = expr_dup_type(tn->tn_type); 3198 ntp->t_tspec = nt; 3199 /* 3200 * Keep t_is_enum even though t_tspec gets converted from ENUM to INT, 3201 * so we are later able to check compatibility of enum types. 3202 */ 3203 return convert(op, 0, ntp, tn); 3204 } 3205 3206 static void 3207 convert_integer_from_floating(op_t op, const type_t *tp, const tnode_t *tn) 3208 { 3209 3210 if (op == CVT) 3211 /* cast from floating point '%s' to integer '%s' */ 3212 query_message(2, type_name(tn->tn_type), type_name(tp)); 3213 else 3214 /* implicit conversion from floating point '%s' to ... */ 3215 query_message(1, type_name(tn->tn_type), type_name(tp)); 3216 } 3217 3218 static bool 3219 should_warn_about_prototype_conversion(tspec_t nt, 3220 tspec_t ot, const tnode_t *ptn) 3221 { 3222 3223 if (nt == ot) 3224 return false; 3225 3226 if (nt == ENUM && ot == INT) 3227 return false; 3228 3229 if (is_floating(nt) != is_floating(ot) || 3230 portable_rank_cmp(nt, ot) != 0) { 3231 /* representation and/or width change */ 3232 if (!is_integer(ot)) 3233 return true; 3234 /* 3235 * XXX: Investigate whether this rule makes sense; see 3236 * tests/usr.bin/xlint/lint1/platform_long.c. 3237 */ 3238 return portable_rank_cmp(ot, INT) > 0; 3239 } 3240 3241 if (!hflag) 3242 return false; 3243 3244 /* 3245 * If the types differ only in sign and the argument has the same 3246 * representation in both types, print no warning. 3247 */ 3248 if (ptn->tn_op == CON && is_integer(nt) && 3249 signed_type(nt) == signed_type(ot) && 3250 !msb(ptn->tn_val.u.integer, ot)) 3251 return false; 3252 3253 return true; 3254 } 3255 3256 /* 3257 * Warn if a prototype causes a type conversion that is different from what 3258 * would happen to the same argument in the absence of a prototype. This 3259 * check is intended for code that needs to stay compatible with pre-C90 C. 3260 * 3261 * Errors/warnings about illegal type combinations are already printed 3262 * in check_assign_types_compatible(). 3263 */ 3264 static void 3265 check_prototype_conversion(int arg, tspec_t nt, tspec_t ot, type_t *tp, 3266 tnode_t *tn) 3267 { 3268 3269 if (!is_arithmetic(nt) || !is_arithmetic(ot)) 3270 return; 3271 3272 /* 3273 * If the type of the formal parameter is char/short, a warning would 3274 * be useless, because functions declared the old style can't expect 3275 * char/short arguments. 3276 */ 3277 if (nt == CHAR || nt == SCHAR || nt == UCHAR || 3278 nt == SHORT || nt == USHORT) 3279 return; 3280 3281 tnode_t *ptn = promote(NOOP, true, tn); 3282 ot = ptn->tn_type->t_tspec; 3283 3284 if (should_warn_about_prototype_conversion(nt, ot, ptn)) { 3285 /* argument %d is converted from '%s' to '%s' ... */ 3286 warning(259, arg, type_name(tn->tn_type), type_name(tp)); 3287 } 3288 } 3289 3290 /* 3291 * When converting a large integer type to a small integer type, in some 3292 * cases the value of the actual expression is further restricted than the 3293 * type bounds, such as in (expr & 0xFF) or (expr % 100) or (expr >> 24). 3294 */ 3295 static bool 3296 can_represent(const type_t *tp, const tnode_t *tn) 3297 { 3298 3299 debug_step("%s: type '%s'", __func__, type_name(tp)); 3300 debug_node(tn); 3301 3302 uint64_t nmask = value_bits(width_in_bits(tp)); 3303 if (!is_uinteger(tp->t_tspec)) 3304 nmask >>= 1; 3305 3306 integer_constraints c = ic_expr(tn); 3307 if ((~c.bclr & ~nmask) == 0) 3308 return true; 3309 3310 integer_constraints tpc = ic_any(tp); 3311 if (is_uinteger(tp->t_tspec) 3312 ? tpc.umin <= c.umin && tpc.umax >= c.umax 3313 : tpc.smin <= c.smin && tpc.smax >= c.smax) 3314 return true; 3315 3316 return false; 3317 } 3318 3319 static bool 3320 should_warn_about_integer_conversion(const type_t *ntp, tspec_t nt, 3321 const tnode_t *otn, tspec_t ot) 3322 { 3323 3324 // XXX: The portable_rank_cmp aims at portable mode, independent of the 3325 // current platform, while can_represent acts on the actual type sizes 3326 // from the current platform. This mix is inconsistent, but anything 3327 // else would make the exact conditions too complicated to grasp. 3328 if (aflag > 0 && portable_rank_cmp(nt, ot) < 0) { 3329 if (ot == LONG || ot == ULONG 3330 || ot == LLONG || ot == ULLONG 3331 #ifdef INT128_SIZE 3332 || ot == INT128 || ot == UINT128 3333 #endif 3334 || aflag > 1) 3335 return !can_represent(ntp, otn); 3336 } 3337 return false; 3338 } 3339 3340 static void 3341 convert_integer_from_integer(op_t op, int arg, tspec_t nt, tspec_t ot, 3342 type_t *tp, tnode_t *tn) 3343 { 3344 3345 if (tn->tn_op == CON) 3346 return; 3347 3348 if (op == CVT) 3349 return; 3350 3351 if (Pflag && pflag && aflag > 0 && 3352 portable_rank_cmp(nt, ot) > 0 && 3353 is_uinteger(nt) != is_uinteger(ot)) { 3354 if (op == FARG) { 3355 /* conversion to '%s' may sign-extend ... */ 3356 warning(297, type_name(tp), arg); 3357 } else { 3358 /* conversion to '%s' may sign-extend ... */ 3359 warning(131, type_name(tp)); 3360 } 3361 } 3362 3363 if (Pflag && portable_rank_cmp(nt, ot) > 0 && 3364 (tn->tn_op == PLUS || tn->tn_op == MINUS || tn->tn_op == MULT || 3365 tn->tn_op == SHL)) { 3366 /* suggest cast from '%s' to '%s' on op '%s' to ... */ 3367 warning(324, type_name(gettyp(ot)), type_name(tp), 3368 op_name(tn->tn_op)); 3369 } 3370 3371 if (should_warn_about_integer_conversion(tp, nt, tn, ot)) { 3372 if (op == FARG) { 3373 /* conversion from '%s' to '%s' may lose ... */ 3374 warning(298, 3375 type_name(tn->tn_type), type_name(tp), arg); 3376 } else { 3377 /* conversion from '%s' to '%s' may lose accuracy */ 3378 warning(132, 3379 type_name(tn->tn_type), type_name(tp)); 3380 } 3381 } 3382 3383 if (any_query_enabled && is_uinteger(nt) != is_uinteger(ot)) 3384 /* implicit conversion changes sign from '%s' to '%s' */ 3385 query_message(3, type_name(tn->tn_type), type_name(tp)); 3386 } 3387 3388 static void 3389 convert_integer_from_pointer(op_t op, tspec_t nt, type_t *tp, tnode_t *tn) 3390 { 3391 3392 if (tn->tn_op == CON) 3393 return; 3394 if (op != CVT) 3395 return; /* We already got an error. */ 3396 if (portable_rank_cmp(nt, PTR) >= 0) 3397 return; 3398 3399 if (pflag && size_in_bits(nt) >= size_in_bits(PTR)) { 3400 /* conversion of pointer to '%s' may lose bits */ 3401 warning(134, type_name(tp)); 3402 } else { 3403 /* conversion of pointer to '%s' loses bits */ 3404 warning(133, type_name(tp)); 3405 } 3406 } 3407 3408 static bool 3409 struct_starts_with(const type_t *struct_tp, const type_t *member_tp) 3410 { 3411 3412 return struct_tp->t_sou->sou_first_member != NULL && 3413 types_compatible(struct_tp->t_sou->sou_first_member->s_type, 3414 member_tp, true, false, NULL); 3415 } 3416 3417 static bool 3418 is_byte_array(const type_t *tp) 3419 { 3420 3421 return tp->t_tspec == ARRAY && 3422 (tp->t_subt->t_tspec == CHAR || tp->t_subt->t_tspec == UCHAR); 3423 } 3424 3425 static bool 3426 union_contains(const type_t *utp, const type_t *mtp) 3427 { 3428 for (const sym_t *mem = utp->t_sou->sou_first_member; 3429 mem != NULL; mem = mem->s_next) { 3430 if (types_compatible(mem->s_type, mtp, true, false, NULL)) 3431 return true; 3432 } 3433 return false; 3434 } 3435 3436 static bool 3437 should_warn_about_pointer_cast(const type_t *nstp, tspec_t nst, 3438 const type_t *ostp, tspec_t ost) 3439 { 3440 3441 while (nst == ARRAY) 3442 nstp = nstp->t_subt, nst = nstp->t_tspec; 3443 while (ost == ARRAY) 3444 ostp = ostp->t_subt, ost = ostp->t_tspec; 3445 3446 if (nst == STRUCT && ost == STRUCT && 3447 (struct_starts_with(nstp, ostp) || 3448 struct_starts_with(ostp, nstp))) 3449 return false; 3450 3451 if (is_incomplete(nstp) || is_incomplete(ostp)) 3452 return false; 3453 3454 if (nst == CHAR || nst == UCHAR) 3455 return false; /* for the sake of traditional C code */ 3456 if (ost == CHAR || ost == UCHAR) 3457 return false; /* for the sake of traditional C code */ 3458 3459 /* Allow cast between pointers to sockaddr variants. */ 3460 if (nst == STRUCT && ost == STRUCT) { 3461 const sym_t *nmem = nstp->t_sou->sou_first_member; 3462 const sym_t *omem = ostp->t_sou->sou_first_member; 3463 while (nmem != NULL && omem != NULL && 3464 types_compatible(nmem->s_type, omem->s_type, 3465 true, false, NULL)) 3466 nmem = nmem->s_next, omem = omem->s_next; 3467 if (nmem != NULL && is_byte_array(nmem->s_type)) 3468 return false; 3469 if (omem != NULL && is_byte_array(omem->s_type)) 3470 return false; 3471 if (nmem == NULL && omem == NULL) 3472 return false; 3473 } 3474 3475 if (nst == UNION || ost == UNION) { 3476 const type_t *union_tp = nst == UNION ? nstp : ostp; 3477 const type_t *other_tp = nst == UNION ? ostp : nstp; 3478 if (union_contains(union_tp, other_tp)) 3479 return false; 3480 } 3481 3482 if (is_struct_or_union(nst) && is_struct_or_union(ost)) 3483 return nstp->t_sou != ostp->t_sou; 3484 3485 enum rank_kind rk1 = type_properties(nst)->tt_rank_kind; 3486 enum rank_kind rk2 = type_properties(ost)->tt_rank_kind; 3487 if (rk1 != rk2 || rk1 == RK_NONE) 3488 return true; 3489 3490 return portable_rank_cmp(nst, ost) != 0; 3491 } 3492 3493 static void 3494 convert_pointer_from_pointer(type_t *ntp, tnode_t *tn) 3495 { 3496 const type_t *nstp = ntp->t_subt; 3497 const type_t *otp = tn->tn_type; 3498 const type_t *ostp = otp->t_subt; 3499 tspec_t nst = nstp->t_tspec; 3500 tspec_t ost = ostp->t_tspec; 3501 3502 if (nst == VOID || ost == VOID) { 3503 /* TODO: C99 behaves like C90 here. */ 3504 if (!allow_trad && !allow_c99 && (nst == FUNC || ost == FUNC)) { 3505 const char *nts, *ots; 3506 /* null pointers are already handled in convert() */ 3507 *(nst == FUNC ? &nts : &ots) = "function pointer"; 3508 *(nst == VOID ? &nts : &ots) = "'void *'"; 3509 /* conversion of %s to %s requires a cast */ 3510 warning(303, ots, nts); 3511 } 3512 return; 3513 } 3514 if (nst == FUNC && ost == FUNC) 3515 return; 3516 if (nst == FUNC || ost == FUNC) { 3517 /* converting '%s' to '%s' is questionable */ 3518 warning(229, type_name(otp), type_name(ntp)); 3519 return; 3520 } 3521 3522 if (hflag && alignment_in_bits(nstp) > alignment_in_bits(ostp) && 3523 ost != CHAR && ost != UCHAR && 3524 !is_incomplete(ostp) && 3525 !(nst == UNION && union_contains(nstp, ostp))) { 3526 /* converting '%s' to '%s' increases alignment ... */ 3527 warning(135, type_name(otp), type_name(ntp), 3528 alignment_in_bits(ostp) / CHAR_SIZE, 3529 alignment_in_bits(nstp) / CHAR_SIZE); 3530 } 3531 3532 if (cflag && should_warn_about_pointer_cast(nstp, nst, ostp, ost)) { 3533 /* pointer cast from '%s' to '%s' may be troublesome */ 3534 warning(247, type_name(otp), type_name(ntp)); 3535 } 3536 } 3537 3538 /* 3539 * Insert a conversion operator, which converts the type of the node 3540 * to another given type. 3541 * 3542 * Possible values for 'op': 3543 * CVT a cast-expression 3544 * binary integer promotion for one of the operands, or a usual 3545 * arithmetic conversion 3546 * binary plain or compound assignments to bit-fields 3547 * FARG 'arg' is the number of the parameter (used for warnings) 3548 * NOOP several other implicit conversions 3549 * ... 3550 */ 3551 tnode_t * 3552 convert(op_t op, int arg, type_t *tp, tnode_t *tn) 3553 { 3554 tspec_t nt = tp->t_tspec; 3555 tspec_t ot = tn->tn_type->t_tspec; 3556 3557 if (allow_trad && allow_c90 && op == FARG) 3558 check_prototype_conversion(arg, nt, ot, tp, tn); 3559 3560 if (nt == BOOL) { 3561 /* No further checks. */ 3562 3563 } else if (is_integer(nt)) { 3564 if (ot == BOOL) { 3565 /* No further checks. */ 3566 } else if (is_integer(ot)) 3567 convert_integer_from_integer(op, arg, nt, ot, tp, tn); 3568 else if (is_floating(ot)) 3569 convert_integer_from_floating(op, tp, tn); 3570 else if (ot == PTR) 3571 convert_integer_from_pointer(op, nt, tp, tn); 3572 3573 } else if (is_floating(nt)) { 3574 /* No further checks. */ 3575 3576 } else if (nt == PTR) { 3577 if (is_null_pointer(tn)) { 3578 /* a null pointer may be assigned to any pointer. */ 3579 } else if (ot == PTR && op == CVT) 3580 convert_pointer_from_pointer(tp, tn); 3581 } 3582 3583 tnode_t *ntn = expr_alloc_tnode(); 3584 ntn->tn_op = CVT; 3585 ntn->tn_type = tp; 3586 ntn->tn_cast = op == CVT; 3587 ntn->tn_sys |= tn->tn_sys; 3588 ntn->tn_right = NULL; 3589 if (tn->tn_op != CON || nt == VOID) { 3590 ntn->tn_left = tn; 3591 } else { 3592 ntn->tn_op = CON; 3593 convert_constant(op, arg, ntn->tn_type, &ntn->tn_val, 3594 &tn->tn_val); 3595 } 3596 3597 return ntn; 3598 } 3599 3600 static void 3601 convert_constant_floating(op_t op, int arg, tspec_t ot, const type_t *tp, 3602 tspec_t nt, val_t *v, val_t *nv) 3603 { 3604 long double max = 0.0, min = 0.0; 3605 3606 switch (nt) { 3607 case CHAR: 3608 max = TARG_CHAR_MAX; min = TARG_CHAR_MIN; break; 3609 case UCHAR: 3610 max = TARG_UCHAR_MAX; min = 0; break; 3611 case SCHAR: 3612 max = TARG_SCHAR_MAX; min = TARG_SCHAR_MIN; break; 3613 case SHORT: 3614 max = TARG_SHRT_MAX; min = TARG_SHRT_MIN; break; 3615 case USHORT: 3616 max = TARG_USHRT_MAX; min = 0; break; 3617 case ENUM: 3618 case INT: 3619 max = TARG_INT_MAX; min = TARG_INT_MIN; break; 3620 case UINT: 3621 max = TARG_UINT_MAX; min = 0; break; 3622 case LONG: 3623 max = TARG_LONG_MAX; min = TARG_LONG_MIN; break; 3624 case ULONG: 3625 max = TARG_ULONG_MAX; min = 0; break; 3626 case LLONG: 3627 max = LLONG_MAX; min = LLONG_MIN; break; 3628 case ULLONG: 3629 max = ULLONG_MAX; min = 0; break; 3630 case FLOAT: 3631 case FCOMPLEX: 3632 max = FLT_MAX; min = -FLT_MAX; break; 3633 case DOUBLE: 3634 case DCOMPLEX: 3635 max = DBL_MAX; min = -DBL_MAX; break; 3636 case PTR: 3637 /* Already got an error because of float --> ptr */ 3638 case LDOUBLE: 3639 case LCOMPLEX: 3640 /* LINTED 248 */ 3641 max = LDBL_MAX; min = -max; break; 3642 default: 3643 lint_assert(/*CONSTCOND*/false); 3644 } 3645 if (v->u.floating > max || v->u.floating < min) { 3646 lint_assert(nt != LDOUBLE); 3647 if (op == FARG) { 3648 /* conversion of '%s' to '%s' is out of range, ... */ 3649 warning(295, 3650 type_name(gettyp(ot)), type_name(tp), arg); 3651 } else { 3652 /* conversion of '%s' to '%s' is out of range */ 3653 warning(119, type_name(gettyp(ot)), type_name(tp)); 3654 } 3655 v->u.floating = v->u.floating > 0 ? max : min; 3656 } 3657 3658 if (nt == FLOAT || nt == FCOMPLEX) 3659 nv->u.floating = (float)v->u.floating; 3660 else if (nt == DOUBLE || nt == DCOMPLEX) 3661 nv->u.floating = (double)v->u.floating; 3662 else if (nt == LDOUBLE || nt == LCOMPLEX) 3663 nv->u.floating = v->u.floating; 3664 else 3665 nv->u.integer = (int64_t)v->u.floating; 3666 } 3667 3668 static bool 3669 convert_constant_to_floating(tspec_t nt, val_t *nv, 3670 tspec_t ot, const val_t *v) 3671 { 3672 if (nt == FLOAT) { 3673 nv->u.floating = (ot == PTR || is_uinteger(ot)) ? 3674 (float)(uint64_t)v->u.integer : (float)v->u.integer; 3675 } else if (nt == DOUBLE) { 3676 nv->u.floating = (ot == PTR || is_uinteger(ot)) ? 3677 (double)(uint64_t)v->u.integer : (double)v->u.integer; 3678 } else if (nt == LDOUBLE) { 3679 nv->u.floating = (ot == PTR || is_uinteger(ot)) 3680 ? (long double)(uint64_t)v->u.integer 3681 : (long double)v->u.integer; 3682 } else 3683 return false; 3684 return true; 3685 } 3686 3687 /* 3688 * Print a warning if bits which were set are lost due to the conversion. 3689 * This can happen with operator ORASS only. 3690 */ 3691 static void 3692 convert_constant_check_range_bitor(size_t nsz, size_t osz, const val_t *v, 3693 uint64_t xmask, op_t op) 3694 { 3695 if (nsz < osz && (v->u.integer & xmask) != 0) { 3696 /* constant truncated by conversion, op '%s' */ 3697 warning(306, op_name(op)); 3698 } 3699 } 3700 3701 static void 3702 convert_constant_check_range_bitand(size_t nsz, size_t osz, 3703 uint64_t xmask, const val_t *nv, 3704 tspec_t ot, const val_t *v, 3705 const type_t *tp, op_t op) 3706 { 3707 if (nsz > osz && 3708 (nv->u.integer & bit((unsigned int)(osz - 1))) != 0 && 3709 (nv->u.integer & xmask) != xmask) { 3710 /* extra bits set to 0 in conversion of '%s' to '%s', ... */ 3711 warning(309, type_name(gettyp(ot)), 3712 type_name(tp), op_name(op)); 3713 } else if (nsz < osz && 3714 (v->u.integer & xmask) != xmask && 3715 (v->u.integer & xmask) != 0) { 3716 /* constant truncated by conversion, op '%s' */ 3717 warning(306, op_name(op)); 3718 } 3719 } 3720 3721 static void 3722 convert_constant_check_range_signed(op_t op, int arg) 3723 { 3724 if (op == ASSIGN) { 3725 /* assignment of negative constant to unsigned type */ 3726 warning(164); 3727 } else if (op == INIT) { 3728 /* initialization of unsigned with negative constant */ 3729 warning(221); 3730 } else if (op == FARG) { 3731 /* conversion of negative constant to unsigned type, ... */ 3732 warning(296, arg); 3733 } else if (modtab[op].m_comparison) { 3734 /* handled by check_integer_comparison() */ 3735 } else { 3736 /* conversion of negative constant to unsigned type */ 3737 warning(222); 3738 } 3739 } 3740 3741 /* 3742 * Loss of significant bit(s). All truncated bits of unsigned types or all 3743 * truncated bits plus the msb of the target for signed types are considered 3744 * to be significant bits. Loss of significant bits means that at least one 3745 * of the bits was set in an unsigned type or that at least one but not all 3746 * of the bits was set in a signed type. Loss of significant bits means that 3747 * it is not possible, also not with necessary casts, to convert back to the 3748 * original type. An example for a necessary cast is: 3749 * char c; int i; c = 128; 3750 * i = c; ** yields -128 ** 3751 * i = (unsigned char)c; ** yields 128 ** 3752 */ 3753 static void 3754 warn_constant_check_range_truncated(op_t op, int arg, const type_t *tp, 3755 tspec_t ot) 3756 { 3757 if (op == ASSIGN && tp->t_bitfield) 3758 /* precision lost in bit-field assignment */ 3759 warning(166); 3760 else if (op == ASSIGN) 3761 /* constant truncated by assignment */ 3762 warning(165); 3763 else if (op == INIT && tp->t_bitfield) 3764 /* bit-field initializer does not fit */ 3765 warning(180); 3766 else if (op == INIT) 3767 /* initializer does not fit */ 3768 warning(178); 3769 else if (op == CASE) 3770 /* case label affected by conversion */ 3771 warning(196); 3772 else if (op == FARG) 3773 /* conversion of '%s' to '%s' is out of range, arg #%d */ 3774 warning(295, type_name(gettyp(ot)), type_name(tp), arg); 3775 else 3776 /* conversion of '%s' to '%s' is out of range */ 3777 warning(119, type_name(gettyp(ot)), type_name(tp)); 3778 } 3779 3780 static void 3781 warn_constant_check_range_loss(op_t op, int arg, const type_t *tp, 3782 tspec_t ot) 3783 { 3784 if (op == ASSIGN && tp->t_bitfield) 3785 /* precision lost in bit-field assignment */ 3786 warning(166); 3787 else if (op == INIT && tp->t_bitfield) 3788 /* bit-field initializer out of range */ 3789 warning(11); 3790 else if (op == CASE) 3791 /* case label affected by conversion */ 3792 warning(196); 3793 else if (op == FARG) 3794 /* conversion of '%s' to '%s' is out of range, arg #%d */ 3795 warning(295, type_name(gettyp(ot)), type_name(tp), arg); 3796 else 3797 /* conversion of '%s' to '%s' is out of range */ 3798 warning(119, type_name(gettyp(ot)), type_name(tp)); 3799 } 3800 3801 static void 3802 convert_constant_check_range(tspec_t ot, const type_t *tp, tspec_t nt, 3803 op_t op, int arg, const val_t *v, val_t *nv) 3804 { 3805 unsigned int obitsz, nbitsz; 3806 uint64_t xmask, xmsk1; 3807 3808 obitsz = size_in_bits(ot); 3809 nbitsz = tp->t_bitfield ? tp->t_bit_field_width : size_in_bits(nt); 3810 xmask = value_bits(nbitsz) ^ value_bits(obitsz); 3811 xmsk1 = value_bits(nbitsz) ^ value_bits(obitsz - 1); 3812 if (op == ORASS || op == BITOR || op == BITXOR) { 3813 convert_constant_check_range_bitor( 3814 nbitsz, obitsz, v, xmask, op); 3815 } else if (op == ANDASS || op == BITAND) { 3816 convert_constant_check_range_bitand( 3817 nbitsz, obitsz, xmask, nv, ot, v, tp, op); 3818 } else if (nt != PTR && is_uinteger(nt) && 3819 ot != PTR && !is_uinteger(ot) && 3820 v->u.integer < 0) 3821 convert_constant_check_range_signed(op, arg); 3822 else if (nv->u.integer != v->u.integer && nbitsz <= obitsz && 3823 (v->u.integer & xmask) != 0 && 3824 (is_uinteger(ot) || (v->u.integer & xmsk1) != xmsk1)) 3825 warn_constant_check_range_truncated(op, arg, tp, ot); 3826 else if (nv->u.integer != v->u.integer) 3827 warn_constant_check_range_loss(op, arg, tp, ot); 3828 } 3829 3830 /*- 3831 * Converts a typed constant to a constant of another type. 3832 * 3833 * op operator which requires conversion 3834 * arg if op is FARG, # of parameter 3835 * tp type to which to convert the constant 3836 * nv new constant 3837 * v old constant 3838 */ 3839 void 3840 convert_constant(op_t op, int arg, const type_t *tp, val_t *nv, val_t *v) 3841 { 3842 /* 3843 * TODO: make 'v' const; the name of this function does not suggest 3844 * that it modifies 'v'. 3845 */ 3846 tspec_t ot = v->v_tspec; 3847 tspec_t nt = nv->v_tspec = tp->t_tspec; 3848 bool range_check = false; 3849 3850 if (nt == BOOL) { /* C99 6.3.1.2 */ 3851 nv->v_unsigned_since_c90 = false; 3852 nv->u.integer = is_nonzero_val(v) ? 1 : 0; 3853 return; 3854 } 3855 3856 if (ot == FLOAT || ot == DOUBLE || ot == LDOUBLE) 3857 convert_constant_floating(op, arg, ot, tp, nt, v, nv); 3858 else if (!convert_constant_to_floating(nt, nv, ot, v)) { 3859 range_check = true; /* Check for lost precision. */ 3860 nv->u.integer = v->u.integer; 3861 } 3862 3863 if (allow_trad && allow_c90 && v->v_unsigned_since_c90 && 3864 (is_floating(nt) || ( 3865 (is_integer(nt) && !is_uinteger(nt) && 3866 portable_rank_cmp(nt, ot) > 0)))) { 3867 /* C90 treats constant as unsigned */ 3868 warning(157); 3869 v->v_unsigned_since_c90 = false; 3870 } 3871 3872 if (is_integer(nt)) { 3873 nv->u.integer = convert_integer(nv->u.integer, nt, 3874 tp->t_bitfield ? tp->t_bit_field_width : size_in_bits(nt)); 3875 } 3876 3877 if (range_check && op != CVT) 3878 convert_constant_check_range(ot, tp, nt, op, arg, v, nv); 3879 } 3880 3881 tnode_t * 3882 build_sizeof(const type_t *tp) 3883 { 3884 unsigned int size_in_bytes = type_size_in_bits(tp) / CHAR_SIZE; 3885 tnode_t *tn = build_integer_constant(SIZEOF_TSPEC, size_in_bytes); 3886 tn->tn_system_dependent = true; 3887 debug_step("build_sizeof '%s' = %u", type_name(tp), size_in_bytes); 3888 return tn; 3889 } 3890 3891 tnode_t * 3892 build_offsetof(const type_t *tp, designation dn) 3893 { 3894 unsigned int offset_in_bits = 0; 3895 3896 if (!is_struct_or_union(tp->t_tspec)) { 3897 /* unacceptable operand of '%s' */ 3898 error(111, "offsetof"); 3899 goto proceed; 3900 } 3901 for (size_t i = 0; i < dn.dn_len; i++) { 3902 const designator *dr = dn.dn_items + i; 3903 if (dr->dr_kind == DK_SUBSCRIPT) { 3904 if (tp->t_tspec != ARRAY) 3905 goto proceed; /* silent error */ 3906 tp = tp->t_subt; 3907 offset_in_bits += (unsigned) dr->dr_subscript 3908 * type_size_in_bits(tp); 3909 } else { 3910 if (!is_struct_or_union(tp->t_tspec)) 3911 goto proceed; /* silent error */ 3912 const char *name = dr->dr_member->s_name; 3913 sym_t *mem = find_member(tp->t_sou, name); 3914 if (mem == NULL) { 3915 /* type '%s' does not have member '%s' */ 3916 error(101, name, type_name(tp)); 3917 goto proceed; 3918 } 3919 tp = mem->s_type; 3920 offset_in_bits += mem->u.s_member.sm_offset_in_bits; 3921 } 3922 } 3923 free(dn.dn_items); 3924 3925 proceed:; 3926 unsigned int offset_in_bytes = offset_in_bits / CHAR_SIZE; 3927 tnode_t *tn = build_integer_constant(SIZEOF_TSPEC, offset_in_bytes); 3928 tn->tn_system_dependent = true; 3929 return tn; 3930 } 3931 3932 unsigned int 3933 type_size_in_bits(const type_t *tp) 3934 { 3935 3936 unsigned int elem = 1; 3937 bool flex = false; 3938 lint_assert(tp != NULL); 3939 while (tp->t_tspec == ARRAY) { 3940 flex = true; /* allow c99 flex arrays [] [0] */ 3941 elem *= tp->t_dim; 3942 tp = tp->t_subt; 3943 } 3944 if (elem == 0 && !flex) { 3945 /* cannot take size/alignment of incomplete type */ 3946 error(143); 3947 elem = 1; 3948 } 3949 3950 unsigned int elsz; 3951 switch (tp->t_tspec) { 3952 case VOID: 3953 /* cannot take size/alignment of void */ 3954 error(146); 3955 elsz = 1; 3956 break; 3957 case FUNC: 3958 /* cannot take size/alignment of function type '%s' */ 3959 error(144, type_name(tp)); 3960 elsz = 1; 3961 break; 3962 case STRUCT: 3963 case UNION: 3964 if (is_incomplete(tp)) { 3965 /* cannot take size/alignment of incomplete type */ 3966 error(143); 3967 elsz = 1; 3968 } else { 3969 elsz = tp->t_sou->sou_size_in_bits; 3970 } 3971 break; 3972 case ENUM: 3973 if (is_incomplete(tp)) { 3974 /* cannot take size/alignment of incomplete type */ 3975 warning(143); 3976 } 3977 /* FALLTHROUGH */ 3978 default: 3979 if (tp->t_bitfield) { 3980 /* cannot take size/alignment of bit-field */ 3981 error(145); 3982 } 3983 elsz = size_in_bits(tp->t_tspec); 3984 lint_assert(elsz > 0); 3985 break; 3986 } 3987 3988 return elem * elsz; 3989 } 3990 3991 /* C11 6.5.3.4, GCC */ 3992 tnode_t * 3993 build_alignof(const type_t *tp) 3994 { 3995 if (tp->t_tspec == FUNC) { 3996 /* cannot take size/alignment of function type '%s' */ 3997 error(144, type_name(tp)); 3998 return NULL; 3999 } 4000 if (tp->t_tspec == VOID) { 4001 /* cannot take size/alignment of void */ 4002 error(146); 4003 return NULL; 4004 } 4005 if (is_incomplete(tp)) { 4006 /* cannot take size/alignment of incomplete type */ 4007 error(143); 4008 return NULL; 4009 } 4010 if (tp->t_bitfield) { 4011 /* cannot take size/alignment of bit-field */ 4012 error(145); 4013 return NULL; 4014 } 4015 return build_integer_constant(SIZEOF_TSPEC, 4016 (int64_t)alignment_in_bits(tp) / CHAR_SIZE); 4017 } 4018 4019 static tnode_t * 4020 cast_to_union(tnode_t *otn, bool sys, type_t *ntp) 4021 { 4022 4023 if (!allow_gcc) { 4024 /* union cast is a GCC extension */ 4025 error(328); 4026 return NULL; 4027 } 4028 4029 for (const sym_t *m = ntp->t_sou->sou_first_member; 4030 m != NULL; m = m->s_next) { 4031 if (types_compatible(m->s_type, otn->tn_type, 4032 false, false, NULL)) { 4033 tnode_t *ntn = build_op(CVT, sys, ntp, otn, NULL); 4034 ntn->tn_cast = true; 4035 return ntn; 4036 } 4037 } 4038 4039 /* type '%s' is not a member of '%s' */ 4040 error(329, type_name(otn->tn_type), type_name(ntp)); 4041 return NULL; 4042 } 4043 4044 tnode_t * 4045 cast(tnode_t *tn, bool sys, type_t *tp) 4046 { 4047 4048 if (tn == NULL) 4049 return NULL; 4050 4051 tn = cconv(tn); 4052 4053 lint_assert(tp != NULL); 4054 tspec_t nt = tp->t_tspec; 4055 tspec_t ot = tn->tn_type->t_tspec; 4056 4057 if (nt == VOID) { 4058 /* 4059 * C90 6.3.4, C99 6.5.4p2 and C11 6.5.4p2 allow any type to be 4060 * cast to void. The only other allowed casts are from a 4061 * scalar type to a scalar type. 4062 */ 4063 } else if (nt == UNION) 4064 return cast_to_union(tn, sys, tp); 4065 else if (nt == STRUCT || nt == ARRAY || nt == FUNC) { 4066 /* Casting to a struct is an undocumented GCC extension. */ 4067 if (!(allow_gcc && nt == STRUCT)) 4068 goto invalid_cast; 4069 } else if (is_struct_or_union(ot)) 4070 goto invalid_cast; 4071 else if (ot == VOID) { 4072 /* improper cast of void expression */ 4073 error(148); 4074 return NULL; 4075 } else if (is_integer(nt) && is_scalar(ot)) { 4076 /* ok */ 4077 } else if (is_floating(nt) && is_arithmetic(ot)) { 4078 /* ok */ 4079 } else if (nt == PTR && is_integer(ot)) { 4080 /* ok */ 4081 } else if (nt == PTR && ot == PTR) { 4082 if (!tp->t_subt->t_const && tn->tn_type->t_subt->t_const) { 4083 if (hflag) 4084 /* cast discards 'const' from type '%s' */ 4085 warning(275, type_name(tn->tn_type)); 4086 } 4087 } else 4088 goto invalid_cast; 4089 4090 if (any_query_enabled && types_compatible(tp, tn->tn_type, 4091 false, false, NULL)) { 4092 /* no-op cast from '%s' to '%s' */ 4093 query_message(6, type_name(tn->tn_type), type_name(tp)); 4094 } 4095 4096 tn = convert(CVT, 0, tp, tn); 4097 tn->tn_cast = true; 4098 tn->tn_sys = sys; 4099 4100 return tn; 4101 4102 invalid_cast: 4103 /* invalid cast from '%s' to '%s' */ 4104 error(147, type_name(tn->tn_type), type_name(tp)); 4105 return NULL; 4106 } 4107 4108 /* 4109 * Create the node for a function argument. 4110 * All necessary conversions and type checks are done in 4111 * build_function_call because build_function_argument has no 4112 * information about the expected parameter types. 4113 */ 4114 tnode_t * 4115 build_function_argument(tnode_t *args, tnode_t *arg) 4116 { 4117 /* 4118 * If there was a serious error in the expression for the argument, 4119 * create a dummy argument so the positions of the remaining arguments 4120 * will not change. 4121 */ 4122 if (arg == NULL) 4123 arg = build_integer_constant(INT, 0); 4124 4125 return build_op(PUSH, arg->tn_sys, arg->tn_type, arg, args); 4126 } 4127 4128 /* 4129 * Compare the type of an argument with the corresponding type of a 4130 * prototype parameter. If it is a valid combination, but both types 4131 * are not the same, insert a conversion to convert the argument into 4132 * the type of the parameter. 4133 */ 4134 static tnode_t * 4135 check_prototype_argument( 4136 int n, /* pos of arg */ 4137 type_t *tp, /* expected type (from prototype) */ 4138 tnode_t *tn) /* argument */ 4139 { 4140 tnode_t *ln = xcalloc(1, sizeof(*ln)); 4141 ln->tn_type = expr_unqualified_type(tp); 4142 ln->tn_lvalue = true; 4143 if (typeok(FARG, n, ln, tn)) { 4144 bool dowarn; 4145 if (!types_compatible(tp, tn->tn_type, 4146 true, false, (dowarn = false, &dowarn)) || dowarn) 4147 tn = convert(FARG, n, tp, tn); 4148 } 4149 free(ln); 4150 return tn; 4151 } 4152 4153 /* 4154 * Check types of all function arguments and insert conversions, 4155 * if necessary. 4156 */ 4157 static tnode_t * 4158 check_function_arguments(type_t *ftp, tnode_t *args) 4159 { 4160 /* get # of parameters in the prototype */ 4161 int npar = 0; 4162 for (const sym_t *p = ftp->t_params; p != NULL; p = p->s_next) 4163 npar++; 4164 4165 /* get # of arguments in the function call */ 4166 int narg = 0; 4167 for (const tnode_t *arg = args; arg != NULL; arg = tn_ck_right(arg)) 4168 narg++; 4169 4170 const sym_t *param = ftp->t_params; 4171 if (ftp->t_proto && npar != narg && !(ftp->t_vararg && npar < narg)) { 4172 /* argument mismatch: %d %s passed, %d expected */ 4173 error(150, narg, narg != 1 ? "arguments" : "argument", npar); 4174 param = NULL; 4175 } 4176 4177 for (int n = 1; n <= narg; n++) { 4178 4179 // The rightmost argument starts the argument list. 4180 tnode_t *arg = args; 4181 for (int i = narg; i > n; i--, arg = arg->tn_right) 4182 continue; 4183 4184 /* some things which are always not allowed */ 4185 tspec_t at = arg->tn_left->tn_type->t_tspec; 4186 if (at == VOID) { 4187 /* void expressions may not be arguments, arg #%d */ 4188 error(151, n); 4189 return NULL; 4190 } 4191 if (is_struct_or_union(at) && 4192 is_incomplete(arg->tn_left->tn_type)) { 4193 /* argument cannot have unknown size, arg #%d */ 4194 error(152, n); 4195 return NULL; 4196 } 4197 if (is_integer(at) && 4198 arg->tn_left->tn_type->t_is_enum && 4199 is_incomplete(arg->tn_left->tn_type)) { 4200 /* argument cannot have unknown size, arg #%d */ 4201 warning(152, n); 4202 } 4203 4204 arg->tn_left = cconv(arg->tn_left); 4205 4206 if (param != NULL) { 4207 arg->tn_left = check_prototype_argument( 4208 n, param->s_type, arg->tn_left); 4209 } else 4210 arg->tn_left = promote(NOOP, true, arg->tn_left); 4211 arg->tn_type = arg->tn_left->tn_type; 4212 4213 if (param != NULL) 4214 param = param->s_next; 4215 } 4216 4217 return args; 4218 } 4219 4220 tnode_t * 4221 build_function_call(tnode_t *func, bool sys, tnode_t *args) 4222 { 4223 4224 if (func == NULL) 4225 return NULL; 4226 4227 op_t fcop = func->tn_op == NAME && func->tn_type->t_tspec == FUNC 4228 ? CALL : ICALL; 4229 4230 check_ctype_function_call(func, args); 4231 4232 func = cconv(func); 4233 4234 if (func->tn_type->t_tspec != PTR || 4235 func->tn_type->t_subt->t_tspec != FUNC) { 4236 /* cannot call '%s', must be a function */ 4237 error(149, type_name(func->tn_type)); 4238 return NULL; 4239 } 4240 4241 args = check_function_arguments(func->tn_type->t_subt, args); 4242 4243 return build_op(fcop, sys, func->tn_type->t_subt->t_subt, func, args); 4244 } 4245 4246 /* 4247 * Return the value of an integral constant expression. 4248 * If the expression is not constant or its type is not an integer 4249 * type, an error message is printed. 4250 */ 4251 val_t * 4252 integer_constant(tnode_t *tn, bool required) 4253 { 4254 4255 if (tn != NULL) 4256 tn = cconv(tn); 4257 if (tn != NULL) 4258 tn = promote(NOOP, false, tn); 4259 4260 val_t *v = xcalloc(1, sizeof(*v)); 4261 4262 if (tn == NULL) { 4263 lint_assert(seen_error); 4264 debug_step("constant node is null; returning 1 instead"); 4265 v->v_tspec = INT; 4266 v->u.integer = 1; 4267 return v; 4268 } 4269 4270 v->v_tspec = tn->tn_type->t_tspec; 4271 4272 if (tn->tn_op == CON) { 4273 lint_assert(tn->tn_type->t_tspec == tn->tn_val.v_tspec); 4274 if (is_integer(tn->tn_val.v_tspec)) { 4275 v->v_unsigned_since_c90 = 4276 tn->tn_val.v_unsigned_since_c90; 4277 v->u.integer = tn->tn_val.u.integer; 4278 return v; 4279 } 4280 v->u.integer = (int64_t)tn->tn_val.u.floating; 4281 } else { 4282 v->u.integer = 1; 4283 } 4284 4285 if (required) 4286 /* integral constant expression expected */ 4287 error(55); 4288 else 4289 /* variable array dimension is a C99/GCC extension */ 4290 c99ism(318); 4291 4292 if (!is_integer(v->v_tspec)) 4293 v->v_tspec = INT; 4294 4295 return v; 4296 } 4297 4298 static bool 4299 is_constcond_false(const tnode_t *tn, tspec_t t) 4300 { 4301 return (t == BOOL || t == INT) && 4302 tn->tn_op == CON && tn->tn_val.u.integer == 0; 4303 } 4304 4305 /* 4306 * Perform some tests on expressions which can't be done in build_binary() 4307 * and functions called by build_binary(). These tests must be done here 4308 * because we need some information about the context in which the operations 4309 * are performed. 4310 * After all tests are performed and dofreeblk is true, expr() frees the 4311 * memory which is used for the expression. 4312 */ 4313 void 4314 expr(tnode_t *tn, bool vctx, bool cond, bool dofreeblk, bool is_do_while) 4315 { 4316 4317 if (tn == NULL) { /* in case of errors */ 4318 expr_free_all(); 4319 return; 4320 } 4321 4322 /* expr() is also called in global initializations */ 4323 if (dcs->d_kind != DLK_EXTERN && !is_do_while) 4324 check_statement_reachable(); 4325 4326 check_expr_misc(tn, vctx, cond, !cond, false, false, false); 4327 if (tn->tn_op == ASSIGN && !tn->tn_parenthesized) { 4328 if (hflag && cond) 4329 /* assignment in conditional context */ 4330 warning(159); 4331 } else if (tn->tn_op == CON) { 4332 if (hflag && cond && !suppress_constcond && 4333 !tn->tn_system_dependent && 4334 !(is_do_while && 4335 is_constcond_false(tn, tn->tn_type->t_tspec))) 4336 /* constant in conditional context */ 4337 warning(161); 4338 } 4339 if (!modtab[tn->tn_op].m_has_side_effect) { 4340 /* 4341 * for left operands of COMMA this warning is already printed 4342 */ 4343 if (tn->tn_op != COMMA && !vctx && !cond) 4344 check_null_effect(tn); 4345 } 4346 debug_node(tn); 4347 4348 if (dofreeblk) 4349 expr_free_all(); 4350 } 4351 4352 /* 4353 * Checks the range of array indices, if possible. 4354 * amper is set if only the address of the element is used. This 4355 * means that the index is allowed to refer to the first element 4356 * after the array. 4357 */ 4358 static void 4359 check_array_index(tnode_t *tn, bool amper) 4360 { 4361 lint_assert(has_operands(tn)); 4362 const tnode_t *ln = tn->tn_left; 4363 const tnode_t *rn = tn->tn_right; 4364 4365 /* We can only check constant indices. */ 4366 if (rn->tn_op != CON) 4367 return; 4368 4369 /* Return if the left node does not stem from an array. */ 4370 if (ln->tn_op != ADDR) 4371 return; 4372 if (ln->tn_left->tn_op != STRING && ln->tn_left->tn_op != NAME) 4373 return; 4374 if (ln->tn_left->tn_type->t_tspec != ARRAY) 4375 return; 4376 4377 /* 4378 * For incomplete array types, we can print a warning only if the index 4379 * is negative. 4380 */ 4381 if (is_incomplete(ln->tn_left->tn_type) && rn->tn_val.u.integer >= 0) 4382 return; 4383 4384 int elsz = length_in_bits(ln->tn_type->t_subt, NULL); 4385 if (elsz == 0) 4386 return; 4387 elsz /= CHAR_SIZE; 4388 4389 /* Change the unit of the index from bytes to element size. */ 4390 int64_t con = is_uinteger(rn->tn_type->t_tspec) 4391 ? (int64_t)((uint64_t)rn->tn_val.u.integer / elsz) 4392 : rn->tn_val.u.integer / elsz; 4393 4394 int dim = ln->tn_left->tn_type->t_dim + (amper ? 1 : 0); 4395 4396 if (!is_uinteger(rn->tn_type->t_tspec) && con < 0) { 4397 /* array subscript cannot be negative: %ld */ 4398 warning(167, (long)con); 4399 } else if (dim > 0 && (uint64_t)con >= (uint64_t)dim) { 4400 /* array subscript cannot be > %d: %ld */ 4401 warning(168, dim - 1, (long)con); 4402 } 4403 } 4404 4405 static void 4406 check_expr_addr(const tnode_t *ln, bool szof, bool fcall) 4407 { 4408 /* XXX: Taking warn_about_unreachable into account here feels wrong. */ 4409 if (ln->tn_op == NAME && (reached || !warn_about_unreachable)) { 4410 if (!szof) 4411 mark_as_set(ln->tn_sym); 4412 mark_as_used(ln->tn_sym, fcall, szof); 4413 } 4414 if (ln->tn_op == INDIR && ln->tn_left->tn_op == PLUS) 4415 check_array_index(ln->tn_left, true); 4416 } 4417 4418 static void 4419 check_expr_load(const tnode_t *ln) 4420 { 4421 if (ln->tn_op == INDIR && ln->tn_left->tn_op == PLUS) 4422 check_array_index(ln->tn_left, false); 4423 } 4424 4425 /* 4426 * If there is an asm statement in one of the compound statements around, 4427 * there may be other side effects, so don't warn. 4428 */ 4429 static bool 4430 is_asm_around(void) 4431 { 4432 for (decl_level *dl = dcs; dl != NULL; dl = dl->d_enclosing) 4433 if (dl->d_asm) 4434 return true; 4435 return false; 4436 } 4437 4438 static void 4439 check_expr_side_effect(const tnode_t *ln, bool szof) 4440 { 4441 4442 /* XXX: Taking warn_about_unreachable into account here feels wrong. */ 4443 if (ln->tn_op == NAME && (reached || !warn_about_unreachable)) { 4444 scl_t sc = ln->tn_sym->s_scl; 4445 if (sc != EXTERN && sc != STATIC && 4446 !ln->tn_sym->s_set && !szof && !is_asm_around()) { 4447 /* '%s' may be used before set */ 4448 warning(158, ln->tn_sym->s_name); 4449 mark_as_set(ln->tn_sym); 4450 } 4451 mark_as_used(ln->tn_sym, false, false); 4452 } 4453 } 4454 4455 static void 4456 check_expr_assign(const tnode_t *ln, bool szof) 4457 { 4458 /* XXX: Taking warn_about_unreachable into account here feels wrong. */ 4459 if (ln->tn_op == NAME && !szof && (reached || !warn_about_unreachable)) { 4460 mark_as_set(ln->tn_sym); 4461 if (ln->tn_sym->s_scl == EXTERN) 4462 outusg(ln->tn_sym); 4463 } 4464 if (ln->tn_op == INDIR && ln->tn_left->tn_op == PLUS) 4465 /* check the range of array indices */ 4466 check_array_index(ln->tn_left, false); 4467 } 4468 4469 static void 4470 check_expr_call(const tnode_t *tn, const tnode_t *ln, 4471 bool szof, bool vctx, bool cond, bool retval_discarded) 4472 { 4473 lint_assert(ln->tn_op == ADDR); 4474 lint_assert(ln->tn_left->tn_op == NAME); 4475 if (!szof && !is_compiler_builtin(ln->tn_left->tn_sym->s_name)) 4476 outcall(tn, vctx || cond, retval_discarded); 4477 } 4478 4479 static void 4480 check_expr_op(const tnode_t *tn, op_t op, const tnode_t *ln, 4481 bool szof, bool fcall, bool vctx, bool cond, 4482 bool retval_discarded, bool eqwarn) 4483 { 4484 switch (op) { 4485 case ADDR: 4486 check_expr_addr(ln, szof, fcall); 4487 break; 4488 case LOAD: 4489 check_expr_load(ln); 4490 /* FALLTHROUGH */ 4491 case PUSH: 4492 case INCBEF: 4493 case DECBEF: 4494 case INCAFT: 4495 case DECAFT: 4496 case ADDASS: 4497 case SUBASS: 4498 case MULASS: 4499 case DIVASS: 4500 case MODASS: 4501 case ANDASS: 4502 case ORASS: 4503 case XORASS: 4504 case SHLASS: 4505 case SHRASS: 4506 case REAL: 4507 case IMAG: 4508 check_expr_side_effect(ln, szof); 4509 break; 4510 case ASSIGN: 4511 check_expr_assign(ln, szof); 4512 break; 4513 case CALL: 4514 check_expr_call(tn, ln, szof, vctx, cond, retval_discarded); 4515 break; 4516 case EQ: 4517 if (hflag && eqwarn) 4518 /* operator '==' found where '=' was expected */ 4519 warning(160); 4520 break; 4521 default: 4522 break; 4523 } 4524 } 4525 4526 /* 4527 * vctx ??? 4528 * cond whether the expression is a condition that 4529 * will be compared with 0 4530 * eqwarn whether the operator '==' might be a 4531 * misspelled '=' 4532 * fcall whether the expression is a function call 4533 * retval_discarded whether the return value of a function call 4534 * is discarded; such calls will be analyzed by 4535 * lint2 in messages 4, 8 and 9 4536 * szof whether the expression is part of a sizeof 4537 * expression, which means that its value is 4538 * discarded since only the type is relevant 4539 */ 4540 void 4541 check_expr_misc(const tnode_t *tn, bool vctx, bool cond, 4542 bool eqwarn, bool fcall, bool retval_discarded, bool szof) 4543 { 4544 4545 if (tn == NULL) 4546 return; 4547 op_t op = tn->tn_op; 4548 if (op == NAME || op == CON || op == STRING) 4549 return; 4550 4551 lint_assert(has_operands(tn)); 4552 tnode_t *ln = tn->tn_left; 4553 tnode_t *rn = tn->tn_right; 4554 check_expr_op(tn, op, ln, 4555 szof, fcall, vctx, cond, retval_discarded, eqwarn); 4556 4557 const mod_t *mp = &modtab[op]; 4558 bool cvctx = mp->m_value_context; 4559 bool ccond = mp->m_compares_with_zero; 4560 bool eq = mp->m_warn_if_operand_eq && 4561 !ln->tn_parenthesized && 4562 rn != NULL && !rn->tn_parenthesized; 4563 4564 /* 4565 * Values of operands of ':' are not used if the type of at least 4566 * one of the operands (for GCC compatibility) is 'void'. 4567 * 4568 * XXX test/value context of QUEST should probably be used as 4569 * context for both operands of COLON. 4570 */ 4571 if (op == COLON && tn->tn_type->t_tspec == VOID) 4572 cvctx = ccond = false; 4573 bool discard = op == CVT && tn->tn_type->t_tspec == VOID; 4574 check_expr_misc(ln, cvctx, ccond, eq, op == CALL, discard, szof); 4575 4576 switch (op) { 4577 case PUSH: 4578 if (rn != NULL) 4579 check_expr_misc(rn, false, false, eq, false, false, 4580 szof); 4581 break; 4582 case LOGAND: 4583 case LOGOR: 4584 check_expr_misc(rn, false, true, eq, false, false, szof); 4585 break; 4586 case COLON: 4587 check_expr_misc(rn, cvctx, ccond, eq, false, false, szof); 4588 break; 4589 case COMMA: 4590 check_expr_misc(rn, vctx, cond, false, false, false, szof); 4591 break; 4592 default: 4593 if (mp->m_binary) 4594 check_expr_misc(rn, true, false, eq, false, false, 4595 szof); 4596 break; 4597 } 4598 } 4599 4600 /* 4601 * Return whether the expression can be used for static initialization. 4602 * 4603 * Constant initialization expressions must be constant or an address 4604 * of a static object with an optional offset. In the first case, 4605 * the result is returned in *offsp. In the second case, the static 4606 * object is returned in *symp and the offset in *offsp. 4607 * 4608 * The expression can consist of PLUS, MINUS, ADDR, NAME, STRING and 4609 * CON. Type conversions are allowed if they do not change binary 4610 * representation (including width). 4611 * 4612 * C99 6.6 "Constant expressions" 4613 * C99 6.7.8p4 restricts initializers for static storage duration 4614 */ 4615 bool 4616 constant_addr(const tnode_t *tn, const sym_t **symp, ptrdiff_t *offsp) 4617 { 4618 const sym_t *sym; 4619 ptrdiff_t offs1, offs2; 4620 tspec_t t, ot; 4621 4622 switch (tn->tn_op) { 4623 case MINUS: 4624 if (tn->tn_right->tn_op == CVT) 4625 return constant_addr(tn->tn_right, symp, offsp); 4626 else if (tn->tn_right->tn_op != CON) 4627 return false; 4628 /* FALLTHROUGH */ 4629 case PLUS: 4630 offs1 = offs2 = 0; 4631 if (tn->tn_left->tn_op == CON) { 4632 offs1 = (ptrdiff_t)tn->tn_left->tn_val.u.integer; 4633 if (!constant_addr(tn->tn_right, &sym, &offs2)) 4634 return false; 4635 } else if (tn->tn_right->tn_op == CON) { 4636 offs2 = (ptrdiff_t)tn->tn_right->tn_val.u.integer; 4637 if (tn->tn_op == MINUS) 4638 offs2 = -offs2; 4639 if (!constant_addr(tn->tn_left, &sym, &offs1)) 4640 return false; 4641 } else { 4642 return false; 4643 } 4644 *symp = sym; 4645 *offsp = offs1 + offs2; 4646 return true; 4647 case ADDR: 4648 if (tn->tn_left->tn_op == NAME) { 4649 *symp = tn->tn_left->tn_sym; 4650 *offsp = 0; 4651 return true; 4652 } else { 4653 /* 4654 * If this were the front end of a compiler, we would 4655 * return a label instead of 0, at least if 4656 * 'tn->tn_left->tn_op == STRING'. 4657 */ 4658 *symp = NULL; 4659 *offsp = 0; 4660 return true; 4661 } 4662 case CVT: 4663 t = tn->tn_type->t_tspec; 4664 ot = tn->tn_left->tn_type->t_tspec; 4665 if ((!is_integer(t) && t != PTR) || 4666 (!is_integer(ot) && ot != PTR)) { 4667 return false; 4668 } 4669 #if 0 4670 /*- 4671 * consider: 4672 * struct foo { 4673 * unsigned char a; 4674 * } f = { 4675 * (unsigned char)(unsigned long) 4676 * (&(((struct foo *)0)->a)) 4677 * }; 4678 * since psize(unsigned long) != psize(unsigned char), 4679 * this fails. 4680 */ 4681 else if (psize(t) != psize(ot)) 4682 return -1; 4683 #endif 4684 return constant_addr(tn->tn_left, symp, offsp); 4685 default: 4686 return false; 4687 } 4688 } 4689 4690 /* Append s2 to s1, then free s2. */ 4691 buffer * 4692 cat_strings(buffer *s1, buffer *s2) 4693 { 4694 4695 if ((s1->data != NULL) != (s2->data != NULL)) { 4696 /* cannot concatenate wide and regular string literals */ 4697 error(292); 4698 return s1; 4699 } 4700 4701 if (s1->data != NULL) { 4702 while (s1->len + s2->len + 1 > s1->cap) 4703 s1->cap *= 2; 4704 s1->data = xrealloc(s1->data, s1->cap); 4705 memcpy(s1->data + s1->len, s2->data, s2->len + 1); 4706 free(s2->data); 4707 } 4708 s1->len += s2->len; 4709 free(s2); 4710 4711 return s1; 4712 } 4713 4714 4715 typedef struct stmt_expr { 4716 memory_pool se_mem; 4717 sym_t *se_sym; 4718 struct stmt_expr *se_enclosing; 4719 } stmt_expr; 4720 4721 static stmt_expr *stmt_exprs; 4722 4723 void 4724 begin_statement_expr(void) 4725 { 4726 debug_enter(); 4727 4728 stmt_expr *se = xmalloc(sizeof(*se)); 4729 se->se_mem = expr_save_memory(); 4730 se->se_sym = NULL; 4731 se->se_enclosing = stmt_exprs; 4732 stmt_exprs = se; 4733 } 4734 4735 void 4736 do_statement_expr(tnode_t *tn) 4737 { 4738 block_level--; 4739 mem_block_level--; 4740 stmt_exprs->se_sym = tn != NULL 4741 ? mktempsym(block_dup_type(tn->tn_type)) 4742 : NULL; /* after a syntax error */ 4743 mem_block_level++; 4744 block_level++; 4745 /* '({ ... })' is a GCC extension */ 4746 gnuism(320); 4747 } 4748 4749 tnode_t * 4750 end_statement_expr(void) 4751 { 4752 tnode_t *tn; 4753 4754 stmt_expr *se = stmt_exprs; 4755 if (se->se_sym == NULL) { 4756 tn = NULL; /* after a syntax error */ 4757 goto end; 4758 } 4759 4760 tn = build_name(se->se_sym, false); 4761 (void)expr_save_memory(); /* leak */ 4762 expr_restore_memory(se->se_mem); 4763 stmt_exprs = se->se_enclosing; 4764 free(se); 4765 4766 end: 4767 debug_leave(); 4768 return tn; 4769 } 4770 4771 bool 4772 in_statement_expr(void) 4773 { 4774 return stmt_exprs != NULL; 4775 } 4776
Indexes created Tue Sep 23 07:09:52 GMT 2025