tree.c revision 1.507
1 /* $NetBSD: tree.c,v 1.507 2023/03/28 14:44:35 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 1.507 2023/03/28 14:44:35 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_endswith(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 static const char * 85 op_name(op_t op) 86 { 87 return modtab[op].m_name; 88 } 89 90 static unsigned 91 width_in_bits(const type_t *tp) 92 { 93 94 lint_assert(is_integer(tp->t_tspec)); 95 return tp->t_bitfield ? tp->t_flen : size_in_bits(tp->t_tspec); 96 } 97 98 static bool 99 ic_maybe_signed(const type_t *tp, const integer_constraints *ic) 100 { 101 102 return !is_uinteger(tp->t_tspec) && 103 (ic->bclr & ((uint64_t)1 << 63)) == 0; 104 } 105 106 static integer_constraints 107 ic_any(const type_t *tp) 108 { 109 integer_constraints c; 110 111 uint64_t vbits = value_bits(width_in_bits(tp)); 112 if (is_uinteger(tp->t_tspec)) { 113 c.smin = INT64_MIN; 114 c.smax = INT64_MAX; 115 c.umin = 0; 116 c.umax = vbits; 117 c.bset = 0; 118 c.bclr = ~c.umax; 119 } else { 120 c.smin = (int64_t)-1 - (int64_t)(vbits >> 1); 121 c.smax = (int64_t)(vbits >> 1); 122 c.umin = 0; 123 c.umax = UINT64_MAX; 124 c.bset = 0; 125 c.bclr = 0; 126 } 127 return c; 128 } 129 130 static integer_constraints 131 ic_con(const type_t *tp, const val_t *v) 132 { 133 integer_constraints c; 134 135 lint_assert(is_integer(tp->t_tspec)); 136 int64_t s = v->v_quad; 137 uint64_t u = (uint64_t)s; 138 c.smin = s; 139 c.smax = s; 140 c.umin = u; 141 c.umax = u; 142 c.bset = u; 143 c.bclr = ~u; 144 return c; 145 } 146 147 static integer_constraints 148 ic_cvt(const type_t *ntp, const type_t *otp, integer_constraints a) 149 { 150 151 if (width_in_bits(ntp) > width_in_bits(otp) && 152 is_uinteger(otp->t_tspec)) 153 return a; 154 return ic_any(ntp); 155 } 156 157 static integer_constraints 158 ic_bitand(integer_constraints a, integer_constraints b) 159 { 160 integer_constraints c; 161 162 c.smin = INT64_MIN; 163 c.smax = INT64_MAX; 164 c.umin = 0; 165 c.umax = UINT64_MAX; 166 c.bset = a.bset & b.bset; 167 c.bclr = a.bclr | b.bclr; 168 return c; 169 } 170 171 static integer_constraints 172 ic_bitor(integer_constraints a, integer_constraints b) 173 { 174 integer_constraints c; 175 176 c.smin = INT64_MIN; 177 c.smax = INT64_MAX; 178 c.umin = 0; 179 c.umax = UINT64_MAX; 180 c.bset = a.bset | b.bset; 181 c.bclr = a.bclr & b.bclr; 182 return c; 183 } 184 185 static integer_constraints 186 ic_mod(const type_t *tp, integer_constraints a, integer_constraints b) 187 { 188 integer_constraints c; 189 190 if (ic_maybe_signed(tp, &a) || ic_maybe_signed(tp, &b)) 191 return ic_any(tp); 192 193 c.smin = INT64_MIN; 194 c.smax = INT64_MAX; 195 c.umin = 0; 196 c.umax = b.umax - 1; 197 c.bset = 0; 198 c.bclr = ~u64_fill_right(c.umax); 199 return c; 200 } 201 202 static integer_constraints 203 ic_shl(const type_t *tp, integer_constraints a, integer_constraints b) 204 { 205 integer_constraints c; 206 unsigned int amount; 207 208 if (ic_maybe_signed(tp, &a)) 209 return ic_any(tp); 210 211 if (b.smin == b.smax && b.smin >= 0 && b.smin < 64) 212 amount = (unsigned int)b.smin; 213 else if (b.umin == b.umax && b.umin < 64) 214 amount = (unsigned int)b.umin; 215 else 216 return ic_any(tp); 217 218 c.smin = INT64_MIN; 219 c.smax = INT64_MAX; 220 c.umin = 0; 221 c.umax = UINT64_MAX; 222 c.bset = a.bset << amount; 223 c.bclr = a.bclr << amount | (((uint64_t)1 << amount) - 1); 224 return c; 225 } 226 227 static integer_constraints 228 ic_shr(const type_t *tp, integer_constraints a, integer_constraints b) 229 { 230 integer_constraints c; 231 unsigned int amount; 232 233 if (ic_maybe_signed(tp, &a)) 234 return ic_any(tp); 235 236 if (b.smin == b.smax && b.smin >= 0 && b.smin < 64) 237 amount = (unsigned int)b.smin; 238 else if (b.umin == b.umax && b.umin < 64) 239 amount = (unsigned int)b.umin; 240 else 241 return ic_any(tp); 242 243 c.smin = INT64_MIN; 244 c.smax = INT64_MAX; 245 c.umin = 0; 246 c.umax = UINT64_MAX; 247 c.bset = a.bset >> amount; 248 c.bclr = a.bclr >> amount | ~(~(uint64_t)0 >> amount); 249 return c; 250 } 251 252 static integer_constraints 253 ic_expr(const tnode_t *tn) 254 { 255 integer_constraints lc, rc; 256 257 lint_assert(is_integer(tn->tn_type->t_tspec)); 258 259 switch (tn->tn_op) { 260 case CON: 261 return ic_con(tn->tn_type, tn->tn_val); 262 case CVT: 263 if (!is_integer(tn->tn_left->tn_type->t_tspec)) 264 return ic_any(tn->tn_type); 265 lc = ic_expr(tn->tn_left); 266 return ic_cvt(tn->tn_type, tn->tn_left->tn_type, lc); 267 case MOD: 268 lc = ic_expr(before_conversion(tn->tn_left)); 269 rc = ic_expr(before_conversion(tn->tn_right)); 270 return ic_mod(tn->tn_type, lc, rc); 271 case SHL: 272 lc = ic_expr(tn->tn_left); 273 rc = ic_expr(tn->tn_right); 274 return ic_shl(tn->tn_type, lc, rc); 275 case SHR: 276 lc = ic_expr(tn->tn_left); 277 rc = ic_expr(tn->tn_right); 278 return ic_shr(tn->tn_type, lc, rc); 279 case BITAND: 280 lc = ic_expr(tn->tn_left); 281 rc = ic_expr(tn->tn_right); 282 return ic_bitand(lc, rc); 283 case BITOR: 284 lc = ic_expr(tn->tn_left); 285 rc = ic_expr(tn->tn_right); 286 return ic_bitor(lc, rc); 287 default: 288 return ic_any(tn->tn_type); 289 } 290 } 291 292 /* Build 'pointer to tp', 'array of tp' or 'function returning tp'. */ 293 type_t * 294 block_derive_type(type_t *tp, tspec_t t) 295 { 296 type_t *tp2; 297 298 tp2 = block_zero_alloc(sizeof(*tp2)); 299 tp2->t_tspec = t; 300 tp2->t_subt = tp; 301 return tp2; 302 } 303 304 /* 305 * Derive 'pointer to tp' or 'function returning tp'. 306 * The memory is freed at the end of the current expression. 307 */ 308 type_t * 309 expr_derive_type(type_t *tp, tspec_t t) 310 { 311 type_t *tp2; 312 313 tp2 = expr_zero_alloc(sizeof(*tp2)); 314 tp2->t_tspec = t; 315 tp2->t_subt = tp; 316 return tp2; 317 } 318 319 /* 320 * Build and initialize a new node. 321 */ 322 static tnode_t * 323 new_tnode(op_t op, bool sys, type_t *type, tnode_t *ln, tnode_t *rn) 324 { 325 326 tnode_t *ntn = expr_alloc_tnode(); 327 ntn->tn_op = op; 328 ntn->tn_type = type; 329 ntn->tn_sys = sys; 330 ntn->tn_left = ln; 331 ntn->tn_right = rn; 332 333 if (op == INDIR || op == FSEL) { 334 lint_assert(ln->tn_type->t_tspec == PTR); 335 tspec_t t = ln->tn_type->t_subt->t_tspec; 336 if (t != FUNC && t != VOID) 337 ntn->tn_lvalue = true; 338 } 339 340 return ntn; 341 } 342 343 /* 344 * Create a node for a constant. 345 */ 346 tnode_t * 347 build_constant(type_t *tp, val_t *v) 348 { 349 tnode_t *n; 350 351 n = expr_alloc_tnode(); 352 n->tn_op = CON; 353 n->tn_type = tp; 354 n->tn_val = expr_zero_alloc(sizeof(*n->tn_val)); 355 n->tn_val->v_tspec = tp->t_tspec; 356 n->tn_val->v_unsigned_since_c90 = v->v_unsigned_since_c90; 357 n->tn_val->v_u = v->v_u; 358 free(v); 359 return n; 360 } 361 362 static tnode_t * 363 build_integer_constant(tspec_t t, int64_t q) 364 { 365 tnode_t *n; 366 367 n = expr_alloc_tnode(); 368 n->tn_op = CON; 369 n->tn_type = gettyp(t); 370 n->tn_val = expr_zero_alloc(sizeof(*n->tn_val)); 371 n->tn_val->v_tspec = t; 372 n->tn_val->v_quad = q; 373 return n; 374 } 375 376 static void 377 fallback_symbol(sym_t *sym) 378 { 379 380 if (Tflag && fallback_symbol_strict_bool(sym)) 381 return; 382 383 if (block_level > 0 && (strcmp(sym->s_name, "__FUNCTION__") == 0 || 384 strcmp(sym->s_name, "__PRETTY_FUNCTION__") == 0)) { 385 /* __FUNCTION__/__PRETTY_FUNCTION__ is a GCC extension */ 386 gnuism(316); 387 sym->s_type = block_derive_type(gettyp(CHAR), PTR); 388 sym->s_type->t_const = true; 389 return; 390 } 391 392 if (block_level > 0 && strcmp(sym->s_name, "__func__") == 0) { 393 if (!allow_c99) 394 /* __func__ is a C99 feature */ 395 warning(317); 396 /* C11 6.4.2.2 */ 397 sym->s_type = block_derive_type(gettyp(CHAR), ARRAY); 398 sym->s_type->t_const = true; 399 sym->s_type->t_dim = (int)strlen(funcsym->s_name) + 1; 400 return; 401 } 402 403 /* '%s' undefined */ 404 error(99, sym->s_name); 405 } 406 407 /* 408 * Functions that are predeclared by GCC or other compilers can be called 409 * with arbitrary arguments. Since lint usually runs after a successful 410 * compilation, it's the compiler's job to catch any errors. 411 */ 412 bool 413 is_compiler_builtin(const char *name) 414 { 415 /* https://gcc.gnu.org/onlinedocs/gcc/C-Extensions.html */ 416 if (allow_gcc) { 417 if (strncmp(name, "__atomic_", 9) == 0 || 418 strncmp(name, "__builtin_", 10) == 0 || 419 strcmp(name, "alloca") == 0 || 420 /* obsolete but still in use, as of 2021 */ 421 strncmp(name, "__sync_", 7) == 0) 422 return true; 423 } 424 425 /* https://software.intel.com/sites/landingpage/IntrinsicsGuide/ */ 426 if (strncmp(name, "_mm_", 4) == 0) 427 return true; 428 429 return false; 430 } 431 432 /* https://gcc.gnu.org/onlinedocs/gcc/Integer-Overflow-Builtins.html */ 433 static bool 434 is_gcc_bool_builtin(const char *name) 435 { 436 return strncmp(name, "__builtin_", 10) == 0 && 437 (str_endswith(name, "_overflow") || 438 str_endswith(name, "_overflow_p")); 439 } 440 441 static void 442 build_name_call(sym_t *sym) 443 { 444 445 if (is_compiler_builtin(sym->s_name)) { 446 /* 447 * Do not warn about these, just assume that 448 * they are regular functions compatible with 449 * non-prototype calling conventions. 450 */ 451 if (allow_gcc && is_gcc_bool_builtin(sym->s_name)) 452 sym->s_type = gettyp(BOOL); 453 454 } else if (allow_c99) { 455 /* function '%s' implicitly declared to return int */ 456 error(215, sym->s_name); 457 } else if (!allow_trad) { 458 /* function '%s' implicitly declared to return int */ 459 warning(215, sym->s_name); 460 } 461 462 /* XXX if !allow_c90, the symbol should be exported to level 0 */ 463 sym->s_type = block_derive_type(sym->s_type, FUNC); 464 } 465 466 /* Create a node for a name (symbol table entry). */ 467 tnode_t * 468 build_name(sym_t *sym, bool is_funcname) 469 { 470 tnode_t *n; 471 472 if (sym->s_scl == NOSCL && !in_gcc_attribute) { 473 sym->s_scl = EXTERN; 474 sym->s_def = DECL; 475 if (is_funcname) 476 build_name_call(sym); 477 else 478 fallback_symbol(sym); 479 } 480 481 lint_assert(sym->s_kind == FVFT || sym->s_kind == FMEMBER); 482 483 n = expr_alloc_tnode(); 484 n->tn_type = sym->s_type; 485 if (sym->s_scl == BOOL_CONST) { 486 n->tn_op = CON; 487 n->tn_val = expr_zero_alloc(sizeof(*n->tn_val)); 488 n->tn_val->v_tspec = BOOL; 489 n->tn_val->v_quad = sym->u.s_bool_constant ? 1 : 0; 490 } else if (sym->s_scl == ENUM_CONST) { 491 n->tn_op = CON; 492 n->tn_val = expr_zero_alloc(sizeof(*n->tn_val)); 493 n->tn_val->v_tspec = INT; /* ENUM is in n->tn_type */ 494 n->tn_val->v_quad = sym->u.s_enum_constant; 495 } else { 496 n->tn_op = NAME; 497 n->tn_sym = sym; 498 if (sym->s_kind == FVFT && sym->s_type->t_tspec != FUNC) 499 n->tn_lvalue = true; 500 } 501 502 return n; 503 } 504 505 tnode_t * 506 build_string(strg_t *strg) 507 { 508 size_t len; 509 tnode_t *n; 510 type_t *tp; 511 512 len = strg->st_len; 513 514 n = expr_alloc_tnode(); 515 516 tp = expr_zero_alloc(sizeof(*tp)); 517 tp->t_tspec = ARRAY; 518 tp->t_subt = gettyp(strg->st_char ? CHAR : WCHAR); 519 tp->t_dim = (int)(len + 1); 520 521 n->tn_op = STRING; 522 n->tn_type = tp; 523 n->tn_lvalue = true; 524 525 n->tn_string = expr_zero_alloc(sizeof(*n->tn_string)); 526 n->tn_string->st_char = strg->st_char; 527 n->tn_string->st_len = len; 528 529 size_t chsize = strg->st_char ? sizeof(char) : sizeof(wchar_t); 530 size_t size = (len + 1) * chsize; 531 n->tn_string->st_mem = expr_zero_alloc(size); 532 (void)memcpy(n->tn_string->st_mem, strg->st_mem, size); 533 free(strg->st_mem); 534 free(strg); 535 536 return n; 537 } 538 539 tnode_t * 540 build_generic_selection(const tnode_t *expr, 541 struct generic_association *sel) 542 { 543 tnode_t *default_result = NULL; 544 545 for (; sel != NULL; sel = sel->ga_prev) { 546 if (expr != NULL && 547 types_compatible(sel->ga_arg, expr->tn_type, 548 false, false, NULL)) 549 return sel->ga_result; 550 else if (sel->ga_arg == NULL) 551 default_result = sel->ga_result; 552 } 553 return default_result; 554 } 555 556 static bool 557 is_out_of_char_range(const tnode_t *tn) 558 { 559 return tn->tn_op == CON && 560 !(0 <= tn->tn_val->v_quad && 561 tn->tn_val->v_quad < 1 << (CHAR_SIZE - 1)); 562 } 563 564 /* 565 * Check for ordered comparisons of unsigned values with 0. 566 */ 567 static void 568 check_integer_comparison(op_t op, tnode_t *ln, tnode_t *rn) 569 { 570 tspec_t lt, rt; 571 572 lt = ln->tn_type->t_tspec; 573 rt = rn->tn_type->t_tspec; 574 575 if (ln->tn_op != CON && rn->tn_op != CON) 576 return; 577 578 if (!is_integer(lt) || !is_integer(rt)) 579 return; 580 581 if (hflag || pflag) { 582 if (lt == CHAR && is_out_of_char_range(rn)) { 583 char buf[128]; 584 (void)snprintf(buf, sizeof(buf), "%s %d", 585 op_name(op), (int)rn->tn_val->v_quad); 586 /* nonportable character comparison '%s' */ 587 warning(230, buf); 588 return; 589 } 590 if (rt == CHAR && is_out_of_char_range(ln)) { 591 char buf[128]; 592 (void)snprintf(buf, sizeof(buf), "%d %s ?", 593 (int)ln->tn_val->v_quad, op_name(op)); 594 /* nonportable character comparison '%s' */ 595 warning(230, buf); 596 return; 597 } 598 } 599 600 if (is_uinteger(lt) && !is_uinteger(rt) && 601 rn->tn_op == CON && rn->tn_val->v_quad <= 0) { 602 if (rn->tn_val->v_quad < 0) { 603 /* operator '%s' compares '%s' with '%s' */ 604 warning(162, op_name(op), 605 type_name(ln->tn_type), "negative constant"); 606 } else if (op == LT || op == GE) { 607 /* operator '%s' compares '%s' with '%s' */ 608 warning(162, op_name(op), type_name(ln->tn_type), "0"); 609 } 610 return; 611 } 612 if (is_uinteger(rt) && !is_uinteger(lt) && 613 ln->tn_op == CON && ln->tn_val->v_quad <= 0) { 614 if (ln->tn_val->v_quad < 0) { 615 /* operator '%s' compares '%s' with '%s' */ 616 warning(162, op_name(op), 617 "negative constant", type_name(rn->tn_type)); 618 } else if (op == GT || op == LE) { 619 /* operator '%s' compares '%s' with '%s' */ 620 warning(162, op_name(op), "0", type_name(rn->tn_type)); 621 } 622 return; 623 } 624 } 625 626 static const tspec_t arith_rank[] = { 627 LDOUBLE, DOUBLE, FLOAT, 628 #ifdef INT128_SIZE 629 UINT128, INT128, 630 #endif 631 UQUAD, QUAD, 632 ULONG, LONG, 633 UINT, INT, 634 }; 635 636 /* Keep unsigned in traditional C */ 637 static tspec_t 638 usual_arithmetic_conversion_trad(tspec_t lt, tspec_t rt) 639 { 640 641 size_t i; 642 for (i = 0; arith_rank[i] != INT; i++) 643 if (lt == arith_rank[i] || rt == arith_rank[i]) 644 break; 645 646 tspec_t t = arith_rank[i]; 647 if (is_uinteger(lt) || is_uinteger(rt)) 648 if (is_integer(t) && !is_uinteger(t)) 649 return unsigned_type(t); 650 return t; 651 } 652 653 static tspec_t 654 usual_arithmetic_conversion_c90(tspec_t lt, tspec_t rt) 655 { 656 657 if (lt == rt) 658 return lt; 659 660 if (lt == LCOMPLEX || rt == LCOMPLEX) 661 return LCOMPLEX; 662 if (lt == DCOMPLEX || rt == DCOMPLEX) 663 return DCOMPLEX; 664 if (lt == FCOMPLEX || rt == FCOMPLEX) 665 return FCOMPLEX; 666 if (lt == LDOUBLE || rt == LDOUBLE) 667 return LDOUBLE; 668 if (lt == DOUBLE || rt == DOUBLE) 669 return DOUBLE; 670 if (lt == FLOAT || rt == FLOAT) 671 return FLOAT; 672 673 /* 674 * If type A has more bits than type B, it should be able to hold all 675 * possible values of type B. 676 */ 677 if (size_in_bits(lt) > size_in_bits(rt)) 678 return lt; 679 if (size_in_bits(lt) < size_in_bits(rt)) 680 return rt; 681 682 size_t i; 683 for (i = 3; arith_rank[i] != INT; i++) 684 if (arith_rank[i] == lt || arith_rank[i] == rt) 685 break; 686 if ((is_uinteger(lt) || is_uinteger(rt)) && 687 !is_uinteger(arith_rank[i])) 688 i--; 689 return arith_rank[i]; 690 } 691 692 static tnode_t * 693 apply_usual_arithmetic_conversions(op_t op, tnode_t *tn, tspec_t t) 694 { 695 type_t *ntp = expr_dup_type(tn->tn_type); 696 ntp->t_tspec = t; 697 if (tn->tn_op != CON) { 698 /* usual arithmetic conversion for '%s' from '%s' to '%s' */ 699 query_message(4, op_name(op), 700 type_name(tn->tn_type), type_name(ntp)); 701 } 702 return convert(op, 0, ntp, tn); 703 } 704 705 /* 706 * Apply the "usual arithmetic conversions" (C99 6.3.1.8), which gives both 707 * operands the same type. 708 */ 709 static void 710 balance(op_t op, tnode_t **lnp, tnode_t **rnp) 711 { 712 713 tspec_t lt = (*lnp)->tn_type->t_tspec; 714 tspec_t rt = (*rnp)->tn_type->t_tspec; 715 if (!is_arithmetic(lt) || !is_arithmetic(rt)) 716 return; 717 718 tspec_t t = allow_c90 719 ? usual_arithmetic_conversion_c90(lt, rt) 720 : usual_arithmetic_conversion_trad(lt, rt); 721 722 if (t != lt) 723 *lnp = apply_usual_arithmetic_conversions(op, *lnp, t); 724 if (t != rt) 725 *rnp = apply_usual_arithmetic_conversions(op, *rnp, t); 726 } 727 728 /* 729 * Create a tree node for the unary & operator 730 */ 731 static tnode_t * 732 build_address(bool sys, tnode_t *tn, bool noign) 733 { 734 tspec_t t; 735 736 if (!noign && ((t = tn->tn_type->t_tspec) == ARRAY || t == FUNC)) { 737 if (!allow_c90) 738 /* '&' before array or function: ignored */ 739 warning(127); 740 return tn; 741 } 742 743 /* eliminate &* */ 744 if (tn->tn_op == INDIR && 745 tn->tn_left->tn_type->t_tspec == PTR && 746 tn->tn_left->tn_type->t_subt == tn->tn_type) { 747 return tn->tn_left; 748 } 749 750 return new_tnode(ADDR, sys, expr_derive_type(tn->tn_type, PTR), 751 tn, NULL); 752 } 753 754 /* 755 * XXX 756 * Note: There appear to be a number of bugs in detecting overflow in 757 * this function. An audit and a set of proper regression tests are needed. 758 * --Perry Metzger, Nov. 16, 2001 759 */ 760 /* 761 * Do only as much as necessary to compute constant expressions. 762 * Called only if the operator allows folding and all operands are constants. 763 */ 764 static tnode_t * 765 fold(tnode_t *tn) 766 { 767 val_t *v; 768 tspec_t t; 769 bool utyp, ovfl; 770 int64_t sl, sr = 0, q = 0, mask; 771 uint64_t ul, ur = 0; 772 tnode_t *cn; 773 774 v = xcalloc(1, sizeof(*v)); 775 v->v_tspec = tn->tn_type->t_tspec; 776 777 t = tn->tn_left->tn_type->t_tspec; 778 utyp = !is_integer(t) || is_uinteger(t); 779 ul = sl = tn->tn_left->tn_val->v_quad; 780 if (is_binary(tn)) 781 ur = sr = tn->tn_right->tn_val->v_quad; 782 783 mask = value_bits(size_in_bits(t)); 784 ovfl = false; 785 786 switch (tn->tn_op) { 787 case UPLUS: 788 q = sl; 789 break; 790 case UMINUS: 791 q = sl == INT64_MIN ? sl : -sl; 792 if (sl != 0 && msb(q, t) == msb(sl, t)) 793 ovfl = true; 794 break; 795 case COMPL: 796 q = ~sl; 797 break; 798 case MULT: 799 if (utyp) { 800 q = ul * ur; 801 if (q != (q & mask)) 802 ovfl = true; 803 else if ((ul != 0) && ((q / ul) != ur)) 804 ovfl = true; 805 } else { 806 q = sl * sr; 807 if (msb(q, t) != (msb(sl, t) ^ msb(sr, t))) 808 ovfl = true; 809 } 810 break; 811 case DIV: 812 if (sr == 0) { 813 /* division by 0 */ 814 error(139); 815 q = utyp ? -1 : INT64_MAX; 816 } else { 817 q = utyp ? (int64_t)(ul / ur) : sl / sr; 818 } 819 break; 820 case MOD: 821 if (sr == 0) { 822 /* modulus by 0 */ 823 error(140); 824 q = 0; 825 } else { 826 q = utyp ? (int64_t)(ul % ur) : sl % sr; 827 } 828 break; 829 case PLUS: 830 q = utyp ? (int64_t)(ul + ur) : sl + sr; 831 if (msb(sl, t) && msb(sr, t) && !msb(q, t)) 832 ovfl = true; 833 if (!utyp && !msb(sl, t) && !msb(sr, t) && msb(q, t)) 834 ovfl = true; 835 break; 836 case MINUS: 837 q = utyp ? (int64_t)(ul - ur) : sl - sr; 838 if (!utyp && msb(sl, t) && !msb(sr, t) && !msb(q, t)) 839 ovfl = true; 840 if (!msb(sl, t) && msb(sr, t) && msb(q, t)) 841 ovfl = true; 842 break; 843 case SHL: 844 /* TODO: warn about out-of-bounds 'sr'. */ 845 /* TODO: warn about overflow in signed '<<'. */ 846 q = utyp ? (int64_t)(ul << (sr & 63)) : sl << (sr & 63); 847 break; 848 case SHR: 849 /* 850 * The sign must be explicitly extended because 851 * shifts of signed values are implementation dependent. 852 */ 853 /* TODO: warn about out-of-bounds 'sr'. */ 854 q = ul >> (sr & 63); 855 q = convert_integer(q, t, size_in_bits(t) - (int)sr); 856 break; 857 case LT: 858 q = (utyp ? ul < ur : sl < sr) ? 1 : 0; 859 break; 860 case LE: 861 q = (utyp ? ul <= ur : sl <= sr) ? 1 : 0; 862 break; 863 case GE: 864 q = (utyp ? ul >= ur : sl >= sr) ? 1 : 0; 865 break; 866 case GT: 867 q = (utyp ? ul > ur : sl > sr) ? 1 : 0; 868 break; 869 case EQ: 870 q = (utyp ? ul == ur : sl == sr) ? 1 : 0; 871 break; 872 case NE: 873 q = (utyp ? ul != ur : sl != sr) ? 1 : 0; 874 break; 875 case BITAND: 876 q = utyp ? (int64_t)(ul & ur) : sl & sr; 877 break; 878 case BITXOR: 879 q = utyp ? (int64_t)(ul ^ ur) : sl ^ sr; 880 break; 881 case BITOR: 882 q = utyp ? (int64_t)(ul | ur) : sl | sr; 883 break; 884 default: 885 lint_assert(/*CONSTCOND*/false); 886 } 887 888 /* XXX does not work for quads. */ 889 if (ovfl || 890 ((uint64_t)(q | mask) != ~(uint64_t)0 && (q & ~mask) != 0)) { 891 if (hflag) 892 /* integer overflow detected, op '%s' */ 893 warning(141, op_name(tn->tn_op)); 894 } 895 896 v->v_quad = convert_integer(q, t, 0); 897 898 cn = build_constant(tn->tn_type, v); 899 if (tn->tn_left->tn_system_dependent) 900 cn->tn_system_dependent = true; 901 if (is_binary(tn) && tn->tn_right->tn_system_dependent) 902 cn->tn_system_dependent = true; 903 904 return cn; 905 } 906 907 /* 908 * Create a new node for one of the operators POINT and ARROW. 909 */ 910 static tnode_t * 911 build_struct_access(op_t op, bool sys, tnode_t *ln, tnode_t *rn) 912 { 913 tnode_t *ntn, *ctn; 914 bool nolval; 915 916 lint_assert(rn->tn_op == NAME); 917 lint_assert(is_member(rn->tn_sym)); 918 919 /* 920 * Remember if the left operand is an lvalue (structure members 921 * are lvalues if and only if the structure itself is an lvalue). 922 */ 923 nolval = op == POINT && !ln->tn_lvalue; 924 925 if (op == POINT) { 926 ln = build_address(sys, ln, true); 927 } else if (ln->tn_type->t_tspec != PTR) { 928 lint_assert(!allow_c90); 929 lint_assert(is_integer(ln->tn_type->t_tspec)); 930 ln = convert(NOOP, 0, expr_derive_type(gettyp(VOID), PTR), ln); 931 } 932 933 ctn = build_integer_constant(PTRDIFF_TSPEC, 934 rn->tn_sym->u.s_member.sm_offset_in_bits / CHAR_SIZE); 935 936 ntn = new_tnode(PLUS, sys, expr_derive_type(rn->tn_type, PTR), 937 ln, ctn); 938 if (ln->tn_op == CON) 939 ntn = fold(ntn); 940 941 if (rn->tn_type->t_bitfield) { 942 ntn = new_tnode(FSEL, sys, ntn->tn_type->t_subt, ntn, NULL); 943 } else { 944 ntn = new_tnode(INDIR, sys, ntn->tn_type->t_subt, ntn, NULL); 945 } 946 947 if (nolval) 948 ntn->tn_lvalue = false; 949 950 return ntn; 951 } 952 953 /* 954 * Get the size in bytes of type tp->t_subt, as a constant expression of type 955 * ptrdiff_t as seen from the target platform. 956 */ 957 static tnode_t * 958 subt_size_in_bytes(type_t *tp) 959 { 960 int elem, elsz_in_bits; 961 962 lint_assert(tp->t_tspec == PTR); 963 tp = tp->t_subt; 964 965 elem = 1; 966 elsz_in_bits = 0; 967 968 while (tp->t_tspec == ARRAY) { 969 elem *= tp->t_dim; 970 tp = tp->t_subt; 971 } 972 973 switch (tp->t_tspec) { 974 case FUNC: 975 /* pointer to function is not allowed here */ 976 error(110); 977 break; 978 case VOID: 979 /* cannot do pointer arithmetic on operand of unknown size */ 980 gnuism(136); 981 break; 982 case STRUCT: 983 case UNION: 984 if ((elsz_in_bits = tp->t_str->sou_size_in_bits) == 0) 985 /* cannot do pointer arithmetic on operand of ... */ 986 error(136); 987 break; 988 case ENUM: 989 if (is_incomplete(tp)) { 990 /* cannot do pointer arithmetic on operand of ... */ 991 warning(136); 992 } 993 /* FALLTHROUGH */ 994 default: 995 if ((elsz_in_bits = size_in_bits(tp->t_tspec)) == 0) { 996 /* cannot do pointer arithmetic on operand of ... */ 997 error(136); 998 } else { 999 lint_assert(elsz_in_bits != -1); 1000 } 1001 break; 1002 } 1003 1004 if (elem == 0 && elsz_in_bits != 0) { 1005 /* cannot do pointer arithmetic on operand of unknown size */ 1006 error(136); 1007 } 1008 1009 if (elsz_in_bits == 0) 1010 elsz_in_bits = CHAR_SIZE; 1011 1012 return build_integer_constant(PTRDIFF_TSPEC, 1013 (int64_t)(elem * elsz_in_bits / CHAR_SIZE)); 1014 } 1015 1016 /* 1017 * Create a node for INCAFT, INCBEF, DECAFT and DECBEF. 1018 */ 1019 static tnode_t * 1020 build_prepost_incdec(op_t op, bool sys, tnode_t *ln) 1021 { 1022 tnode_t *cn, *ntn; 1023 1024 lint_assert(ln != NULL); 1025 1026 if (ln->tn_type->t_tspec == PTR) { 1027 cn = subt_size_in_bytes(ln->tn_type); 1028 } else { 1029 cn = build_integer_constant(INT, (int64_t)1); 1030 } 1031 ntn = new_tnode(op, sys, ln->tn_type, ln, cn); 1032 1033 return ntn; 1034 } 1035 1036 static void 1037 check_enum_array_index(const tnode_t *ln, const tnode_t *rn) 1038 { 1039 int max_array_index; 1040 int64_t max_enum_value; 1041 const struct sym *ec, *max_ec; 1042 const type_t *lt, *rt; 1043 1044 if (ln->tn_op != ADDR || ln->tn_left->tn_op != NAME) 1045 return; 1046 1047 lt = ln->tn_left->tn_type; 1048 if (lt->t_tspec != ARRAY || lt->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 rt = rn->tn_left->tn_type; 1057 ec = rt->t_enum->en_first_enumerator; 1058 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 max_enum_value = max_ec->u.s_enum_constant; 1065 lint_assert(INT_MIN <= max_enum_value && max_enum_value <= INT_MAX); 1066 1067 max_array_index = lt->t_dim - 1; 1068 if (max_enum_value == max_array_index) 1069 return; 1070 1071 /* 1072 * If the name of the largest enum constant contains 'MAX' or 'NUM', 1073 * that constant is typically not part of the allowed enum values but 1074 * a marker for the number of actual enum values. 1075 */ 1076 if (max_enum_value == max_array_index + 1 && 1077 (strstr(max_ec->s_name, "MAX") != NULL || 1078 strstr(max_ec->s_name, "max") != NULL || 1079 strstr(max_ec->s_name, "NUM") != NULL || 1080 strstr(max_ec->s_name, "num") != NULL)) 1081 return; 1082 1083 /* maximum value %d of '%s' does not match maximum array index %d */ 1084 warning(348, (int)max_enum_value, type_name(rt), max_array_index); 1085 print_previous_declaration(max_ec); 1086 } 1087 1088 /* 1089 * Create a node for operators PLUS and MINUS. 1090 */ 1091 static tnode_t * 1092 build_plus_minus(op_t op, bool sys, tnode_t *ln, tnode_t *rn) 1093 { 1094 1095 /* If pointer and integer, then pointer to the lhs. */ 1096 if (rn->tn_type->t_tspec == PTR && is_integer(ln->tn_type->t_tspec)) { 1097 tnode_t *tmp = ln; 1098 ln = rn; 1099 rn = tmp; 1100 /* pointer addition has integer on the left-hand side */ 1101 query_message(5); 1102 } 1103 1104 /* pointer +- integer */ 1105 if (ln->tn_type->t_tspec == PTR && rn->tn_type->t_tspec != PTR) { 1106 lint_assert(is_integer(rn->tn_type->t_tspec)); 1107 1108 check_ctype_macro_invocation(ln, rn); 1109 check_enum_array_index(ln, rn); 1110 1111 tnode_t *elsz = subt_size_in_bytes(ln->tn_type); 1112 if (rn->tn_type->t_tspec != elsz->tn_type->t_tspec) 1113 rn = convert(NOOP, 0, elsz->tn_type, rn); 1114 1115 tnode_t *prod = new_tnode(MULT, sys, rn->tn_type, rn, elsz); 1116 if (rn->tn_op == CON) 1117 prod = fold(prod); 1118 1119 return new_tnode(op, sys, ln->tn_type, ln, prod); 1120 } 1121 1122 /* pointer - pointer */ 1123 if (rn->tn_type->t_tspec == PTR) { 1124 lint_assert(ln->tn_type->t_tspec == PTR); 1125 lint_assert(op == MINUS); 1126 1127 type_t *ptrdiff = gettyp(PTRDIFF_TSPEC); 1128 tnode_t *raw_diff = new_tnode(op, sys, ptrdiff, ln, rn); 1129 if (ln->tn_op == CON && rn->tn_op == CON) 1130 raw_diff = fold(raw_diff); 1131 1132 tnode_t *elsz = subt_size_in_bytes(ln->tn_type); 1133 balance(NOOP, &raw_diff, &elsz); 1134 1135 return new_tnode(DIV, sys, ptrdiff, raw_diff, elsz); 1136 } 1137 1138 return new_tnode(op, sys, ln->tn_type, ln, rn); 1139 } 1140 1141 /* 1142 * Create a node for operators SHL and SHR. 1143 */ 1144 static tnode_t * 1145 build_bit_shift(op_t op, bool sys, tnode_t *ln, tnode_t *rn) 1146 { 1147 1148 if (!allow_c90 && rn->tn_type->t_tspec != INT) 1149 rn = convert(NOOP, 0, gettyp(INT), rn); 1150 return new_tnode(op, sys, ln->tn_type, ln, rn); 1151 } 1152 1153 static bool 1154 is_null_pointer(const tnode_t *tn) 1155 { 1156 tspec_t t = tn->tn_type->t_tspec; 1157 1158 return ((t == PTR && tn->tn_type->t_subt->t_tspec == VOID) || 1159 is_integer(t)) 1160 && (tn->tn_op == CON && tn->tn_val->v_quad == 0); 1161 } 1162 1163 /* Return a type based on tp1, with added qualifiers from tp2. */ 1164 static type_t * 1165 merge_qualifiers(type_t *tp1, const type_t *tp2) 1166 { 1167 type_t *ntp, *nstp; 1168 bool c1, c2, v1, v2; 1169 1170 lint_assert(tp1->t_tspec == PTR); 1171 lint_assert(tp2->t_tspec == PTR); 1172 1173 c1 = tp1->t_subt->t_const; 1174 c2 = tp2->t_subt->t_const; 1175 v1 = tp1->t_subt->t_volatile; 1176 v2 = tp2->t_subt->t_volatile; 1177 1178 if (c1 == (c1 | c2) && v1 == (v1 | v2)) 1179 return tp1; 1180 1181 nstp = expr_dup_type(tp1->t_subt); 1182 nstp->t_const |= c2; 1183 nstp->t_volatile |= v2; 1184 1185 ntp = expr_dup_type(tp1); 1186 ntp->t_subt = nstp; 1187 return ntp; 1188 } 1189 1190 /* See C99 6.5.15 "Conditional operator". */ 1191 static tnode_t * 1192 build_colon(bool sys, tnode_t *ln, tnode_t *rn) 1193 { 1194 tspec_t lt, rt; 1195 type_t *tp; 1196 1197 lt = ln->tn_type->t_tspec; 1198 rt = rn->tn_type->t_tspec; 1199 1200 if (is_arithmetic(lt) && is_arithmetic(rt)) { 1201 /* The operands were already balanced in build_binary. */ 1202 tp = ln->tn_type; 1203 } else if (lt == BOOL && rt == BOOL) { 1204 tp = ln->tn_type; 1205 } else if (lt == VOID || rt == VOID) { 1206 tp = gettyp(VOID); 1207 } else if (is_struct_or_union(lt)) { 1208 /* Both types must be identical. */ 1209 lint_assert(is_struct_or_union(rt)); 1210 lint_assert(ln->tn_type->t_str == rn->tn_type->t_str); 1211 if (is_incomplete(ln->tn_type)) { 1212 /* unknown operand size, op '%s' */ 1213 error(138, op_name(COLON)); 1214 return NULL; 1215 } 1216 tp = ln->tn_type; 1217 } else if (lt == PTR && is_integer(rt)) { 1218 if (rt != PTRDIFF_TSPEC) 1219 rn = convert(NOOP, 0, gettyp(PTRDIFF_TSPEC), rn); 1220 tp = ln->tn_type; 1221 } else if (rt == PTR && is_integer(lt)) { 1222 if (lt != PTRDIFF_TSPEC) 1223 ln = convert(NOOP, 0, gettyp(PTRDIFF_TSPEC), ln); 1224 tp = rn->tn_type; 1225 } else if (lt == PTR && is_null_pointer(rn)) { 1226 tp = merge_qualifiers(ln->tn_type, rn->tn_type); 1227 } else if (rt == PTR && is_null_pointer(ln)) { 1228 tp = merge_qualifiers(rn->tn_type, ln->tn_type); 1229 } else if (lt == PTR && ln->tn_type->t_subt->t_tspec == VOID) { 1230 tp = merge_qualifiers(ln->tn_type, rn->tn_type); 1231 } else if (rt == PTR && rn->tn_type->t_subt->t_tspec == VOID) { 1232 tp = merge_qualifiers(rn->tn_type, ln->tn_type); 1233 } else { 1234 /* 1235 * XXX For now we simply take the left type. This is 1236 * probably wrong, if one type contains a function prototype 1237 * and the other one, at the same place, only an old-style 1238 * declaration. 1239 */ 1240 tp = merge_qualifiers(ln->tn_type, rn->tn_type); 1241 } 1242 1243 return new_tnode(COLON, sys, tp, ln, rn); 1244 } 1245 1246 /* TODO: check for varargs */ 1247 static bool 1248 is_cast_redundant(const tnode_t *tn) 1249 { 1250 const type_t *ntp = tn->tn_type, *otp = tn->tn_left->tn_type; 1251 tspec_t nt = ntp->t_tspec, ot = otp->t_tspec; 1252 1253 if (nt == BOOL || ot == BOOL) 1254 return nt == BOOL && ot == BOOL; 1255 1256 if (is_integer(nt) && is_integer(ot)) { 1257 unsigned int nw = width_in_bits(ntp), ow = width_in_bits(otp); 1258 if (is_uinteger(nt) == is_uinteger(ot)) 1259 return nw >= ow; 1260 return is_uinteger(ot) && nw > ow; 1261 } 1262 1263 if (is_complex(nt) || is_complex(ot)) 1264 return is_complex(nt) && is_complex(ot) && 1265 size_in_bits(nt) >= size_in_bits(ot); 1266 1267 if (is_floating(nt) && is_floating(ot)) 1268 return size_in_bits(nt) >= size_in_bits(ot); 1269 1270 if (nt == PTR && ot == PTR) { 1271 if (!ntp->t_subt->t_const && otp->t_subt->t_const) 1272 return false; 1273 if (!ntp->t_subt->t_volatile && otp->t_subt->t_volatile) 1274 return false; 1275 1276 if (ntp->t_subt->t_tspec == VOID || 1277 otp->t_subt->t_tspec == VOID || 1278 types_compatible(ntp->t_subt, otp->t_subt, 1279 false, false, NULL)) 1280 return true; 1281 } 1282 1283 return false; 1284 } 1285 1286 /* 1287 * Create a node for an assignment operator (both = and op= ). 1288 */ 1289 static tnode_t * 1290 build_assignment(op_t op, bool sys, tnode_t *ln, tnode_t *rn) 1291 { 1292 tspec_t lt, rt; 1293 tnode_t *ntn, *ctn; 1294 1295 lint_assert(ln != NULL); 1296 lint_assert(rn != NULL); 1297 1298 lt = ln->tn_type->t_tspec; 1299 rt = rn->tn_type->t_tspec; 1300 1301 if ((op == ADDASS || op == SUBASS) && lt == PTR) { 1302 lint_assert(is_integer(rt)); 1303 ctn = subt_size_in_bytes(ln->tn_type); 1304 if (rn->tn_type->t_tspec != ctn->tn_type->t_tspec) 1305 rn = convert(NOOP, 0, ctn->tn_type, rn); 1306 rn = new_tnode(MULT, sys, rn->tn_type, rn, ctn); 1307 if (rn->tn_left->tn_op == CON) 1308 rn = fold(rn); 1309 } 1310 1311 if ((op == ASSIGN || op == RETURN || op == INIT) && 1312 (lt == STRUCT || rt == STRUCT)) { 1313 lint_assert(lt == rt); 1314 lint_assert(ln->tn_type->t_str == rn->tn_type->t_str); 1315 if (is_incomplete(ln->tn_type)) { 1316 if (op == RETURN) { 1317 /* cannot return incomplete type */ 1318 error(212); 1319 } else { 1320 /* unknown operand size, op '%s' */ 1321 error(138, op_name(op)); 1322 } 1323 return NULL; 1324 } 1325 } 1326 1327 if (op == SHLASS) { 1328 if (portable_size_in_bits(lt) < portable_size_in_bits(rt)) { 1329 if (hflag) 1330 /* semantics of '%s' change in ANSI C; ... */ 1331 warning(118, "<<="); 1332 } 1333 } else if (op != SHRASS) { 1334 if (op == ASSIGN || lt != PTR) { 1335 if (lt != rt || 1336 (ln->tn_type->t_bitfield && rn->tn_op == CON)) { 1337 rn = convert(op, 0, ln->tn_type, rn); 1338 rt = lt; 1339 } 1340 } 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 ntn = new_tnode(op, sys, ln->tn_type, ln, rn); 1352 1353 return ntn; 1354 } 1355 1356 /* 1357 * Create a node for REAL, IMAG 1358 */ 1359 static tnode_t * 1360 build_real_imag(op_t op, bool sys, tnode_t *ln) 1361 { 1362 tnode_t *cn, *ntn; 1363 1364 lint_assert(ln != NULL); 1365 1366 if (ln->tn_op == NAME) { 1367 /* 1368 * This may be too much, but it avoids wrong warnings. 1369 * See d_c99_complex_split.c. 1370 */ 1371 mark_as_used(ln->tn_sym, false, false); 1372 mark_as_set(ln->tn_sym); 1373 } 1374 1375 switch (ln->tn_type->t_tspec) { 1376 case LCOMPLEX: 1377 /* XXX: integer and LDOUBLE don't match. */ 1378 cn = build_integer_constant(LDOUBLE, (int64_t)1); 1379 break; 1380 case DCOMPLEX: 1381 /* XXX: integer and DOUBLE don't match. */ 1382 cn = build_integer_constant(DOUBLE, (int64_t)1); 1383 break; 1384 case FCOMPLEX: 1385 /* XXX: integer and FLOAT don't match. */ 1386 cn = build_integer_constant(FLOAT, (int64_t)1); 1387 break; 1388 default: 1389 /* '__%s__' is illegal for type '%s' */ 1390 error(276, op == REAL ? "real" : "imag", 1391 type_name(ln->tn_type)); 1392 return NULL; 1393 } 1394 ntn = new_tnode(op, sys, cn->tn_type, ln, cn); 1395 ntn->tn_lvalue = true; 1396 1397 return ntn; 1398 } 1399 1400 static bool 1401 is_confusing_precedence(op_t op, op_t lop, bool lparen, op_t rop, bool rparen) 1402 { 1403 1404 if (op == SHL || op == SHR) { 1405 if (!lparen && (lop == PLUS || lop == MINUS)) 1406 return true; 1407 if (!rparen && (rop == PLUS || rop == MINUS)) 1408 return true; 1409 return false; 1410 } 1411 1412 if (op == LOGOR) { 1413 if (!lparen && lop == LOGAND) 1414 return true; 1415 if (!rparen && rop == LOGAND) 1416 return true; 1417 return false; 1418 } 1419 1420 lint_assert(op == BITAND || op == BITXOR || op == BITOR); 1421 if (!lparen && lop != op) { 1422 if (lop == PLUS || lop == MINUS) 1423 return true; 1424 if (lop == BITAND || lop == BITXOR) 1425 return true; 1426 } 1427 if (!rparen && rop != op) { 1428 if (rop == PLUS || rop == MINUS) 1429 return true; 1430 if (rop == BITAND || rop == BITXOR) 1431 return true; 1432 } 1433 return false; 1434 } 1435 1436 /* 1437 * Print a warning if the given node has operands which should be 1438 * parenthesized. 1439 * 1440 * XXX Does not work if an operand is a constant expression. Constant 1441 * expressions are already folded. 1442 */ 1443 static void 1444 check_precedence_confusion(tnode_t *tn) 1445 { 1446 tnode_t *ln, *rn; 1447 1448 if (!hflag) 1449 return; 1450 1451 debug_node(tn); 1452 1453 lint_assert(is_binary(tn)); 1454 for (ln = tn->tn_left; ln->tn_op == CVT; ln = ln->tn_left) 1455 continue; 1456 for (rn = tn->tn_right; rn->tn_op == CVT; rn = rn->tn_left) 1457 continue; 1458 1459 if (is_confusing_precedence(tn->tn_op, 1460 ln->tn_op, ln->tn_parenthesized, 1461 rn->tn_op, rn->tn_parenthesized)) { 1462 /* precedence confusion possible: parenthesize! */ 1463 warning(169); 1464 } 1465 } 1466 1467 /* 1468 * Fold constant nodes, as much as is needed for comparing the value with 0. 1469 */ 1470 static tnode_t * 1471 fold_bool(tnode_t *tn) 1472 { 1473 bool l, r; 1474 val_t *v; 1475 1476 v = xcalloc(1, sizeof(*v)); 1477 v->v_tspec = tn->tn_type->t_tspec; 1478 lint_assert(v->v_tspec == INT || (Tflag && v->v_tspec == BOOL)); 1479 1480 l = constant_is_nonzero(tn->tn_left); 1481 r = is_binary(tn) && constant_is_nonzero(tn->tn_right); 1482 1483 switch (tn->tn_op) { 1484 case NOT: 1485 if (hflag && !constcond_flag) 1486 /* constant argument to '!' */ 1487 warning(239); 1488 v->v_quad = !l ? 1 : 0; 1489 break; 1490 case LOGAND: 1491 v->v_quad = l && r ? 1 : 0; 1492 break; 1493 case LOGOR: 1494 v->v_quad = l || r ? 1 : 0; 1495 break; 1496 default: 1497 lint_assert(/*CONSTCOND*/false); 1498 } 1499 1500 return build_constant(tn->tn_type, v); 1501 } 1502 1503 static ldbl_t 1504 floating_error_value(tspec_t t, ldbl_t lv) 1505 { 1506 if (t == FLOAT) { 1507 return lv < 0 ? -FLT_MAX : FLT_MAX; 1508 } else if (t == DOUBLE) { 1509 return lv < 0 ? -DBL_MAX : DBL_MAX; 1510 } else { 1511 /* LINTED 248: floating-point constant out of range */ 1512 ldbl_t max = LDBL_MAX; 1513 return lv < 0 ? -max : max; 1514 } 1515 } 1516 1517 /* 1518 * Fold constant nodes having operands with floating point type. 1519 */ 1520 static tnode_t * 1521 fold_float(tnode_t *tn) 1522 { 1523 val_t *v; 1524 tspec_t t; 1525 ldbl_t lv, rv = 0; 1526 1527 fpe = 0; 1528 v = xcalloc(1, sizeof(*v)); 1529 v->v_tspec = t = tn->tn_type->t_tspec; 1530 1531 lint_assert(is_floating(t)); 1532 lint_assert(t == tn->tn_left->tn_type->t_tspec); 1533 lint_assert(!is_binary(tn) || t == tn->tn_right->tn_type->t_tspec); 1534 1535 lv = tn->tn_left->tn_val->v_ldbl; 1536 if (is_binary(tn)) 1537 rv = tn->tn_right->tn_val->v_ldbl; 1538 1539 switch (tn->tn_op) { 1540 case UPLUS: 1541 v->v_ldbl = lv; 1542 break; 1543 case UMINUS: 1544 v->v_ldbl = -lv; 1545 break; 1546 case MULT: 1547 v->v_ldbl = lv * rv; 1548 break; 1549 case DIV: 1550 if (rv == 0.0) { 1551 /* division by 0 */ 1552 error(139); 1553 v->v_ldbl = floating_error_value(t, lv); 1554 } else { 1555 v->v_ldbl = lv / rv; 1556 } 1557 break; 1558 case PLUS: 1559 v->v_ldbl = lv + rv; 1560 break; 1561 case MINUS: 1562 v->v_ldbl = lv - rv; 1563 break; 1564 case LT: 1565 v->v_quad = lv < rv ? 1 : 0; 1566 break; 1567 case LE: 1568 v->v_quad = lv <= rv ? 1 : 0; 1569 break; 1570 case GE: 1571 v->v_quad = lv >= rv ? 1 : 0; 1572 break; 1573 case GT: 1574 v->v_quad = lv > rv ? 1 : 0; 1575 break; 1576 case EQ: 1577 v->v_quad = lv == rv ? 1 : 0; 1578 break; 1579 case NE: 1580 v->v_quad = lv != rv ? 1 : 0; 1581 break; 1582 default: 1583 lint_assert(/*CONSTCOND*/false); 1584 } 1585 1586 lint_assert(fpe != 0 || isnan((double)v->v_ldbl) == 0); 1587 if (fpe != 0 || isfinite((double)v->v_ldbl) == 0 || 1588 (t == FLOAT && 1589 (v->v_ldbl > FLT_MAX || v->v_ldbl < -FLT_MAX)) || 1590 (t == DOUBLE && 1591 (v->v_ldbl > DBL_MAX || v->v_ldbl < -DBL_MAX))) { 1592 /* floating point overflow on operator '%s' */ 1593 warning(142, op_name(tn->tn_op)); 1594 v->v_ldbl = floating_error_value(t, v->v_ldbl); 1595 fpe = 0; 1596 } 1597 1598 return build_constant(tn->tn_type, v); 1599 } 1600 1601 /* 1602 * Create a tree node for a binary operator and its two operands. Also called 1603 * for unary operators; in that case rn is NULL. 1604 * 1605 * Function calls, sizeof and casts are handled elsewhere. 1606 */ 1607 tnode_t * 1608 build_binary(tnode_t *ln, op_t op, bool sys, tnode_t *rn) 1609 { 1610 const mod_t *mp; 1611 tnode_t *ntn; 1612 type_t *rettp; 1613 1614 mp = &modtab[op]; 1615 1616 /* If there was an error in one of the operands, return. */ 1617 if (ln == NULL || (mp->m_binary && rn == NULL)) 1618 return NULL; 1619 1620 /* 1621 * Apply class conversions to the left operand, but only if its 1622 * value is needed or it is compared with zero. 1623 */ 1624 if (mp->m_value_context || mp->m_compares_with_zero) 1625 ln = cconv(ln); 1626 /* 1627 * The right operand is almost always in a test or value context, 1628 * except if it is a struct or union member. 1629 */ 1630 if (mp->m_binary && op != ARROW && op != POINT) 1631 rn = cconv(rn); 1632 1633 /* 1634 * Print some warnings for comparisons of unsigned values with 1635 * constants lower than or equal to null. This must be done 1636 * before promote() because otherwise unsigned char and unsigned 1637 * short would be promoted to int. Types are also tested to be 1638 * CHAR, which would also become int. 1639 */ 1640 if (mp->m_comparison) 1641 check_integer_comparison(op, ln, rn); 1642 1643 if (mp->m_value_context || mp->m_compares_with_zero) 1644 ln = promote(op, false, ln); 1645 if (mp->m_binary && op != ARROW && op != POINT && 1646 op != ASSIGN && op != RETURN && op != INIT) { 1647 rn = promote(op, false, rn); 1648 } 1649 1650 /* 1651 * If the result of the operation is different for signed or 1652 * unsigned operands and one of the operands is signed only in 1653 * ANSI C, print a warning. 1654 */ 1655 if (mp->m_warn_if_left_unsigned_in_c90 && 1656 ln->tn_op == CON && ln->tn_val->v_unsigned_since_c90) { 1657 /* ANSI C treats constant as unsigned, op '%s' */ 1658 warning(218, mp->m_name); 1659 ln->tn_val->v_unsigned_since_c90 = false; 1660 } 1661 if (mp->m_warn_if_right_unsigned_in_c90 && 1662 rn->tn_op == CON && rn->tn_val->v_unsigned_since_c90) { 1663 /* ANSI C treats constant as unsigned, op '%s' */ 1664 warning(218, mp->m_name); 1665 rn->tn_val->v_unsigned_since_c90 = false; 1666 } 1667 1668 /* Make sure both operands are of the same type */ 1669 if (mp->m_balance_operands || (!allow_c90 && (op == SHL || op == SHR))) 1670 balance(op, &ln, &rn); 1671 1672 /* 1673 * Check types for compatibility with the operation and mutual 1674 * compatibility. Return if there are serious problems. 1675 */ 1676 if (!typeok(op, 0, ln, rn)) 1677 return NULL; 1678 1679 /* And now create the node. */ 1680 switch (op) { 1681 case POINT: 1682 case ARROW: 1683 ntn = build_struct_access(op, sys, ln, rn); 1684 break; 1685 case INCAFT: 1686 case DECAFT: 1687 case INCBEF: 1688 case DECBEF: 1689 ntn = build_prepost_incdec(op, sys, ln); 1690 break; 1691 case ADDR: 1692 ntn = build_address(sys, ln, false); 1693 break; 1694 case INDIR: 1695 ntn = new_tnode(INDIR, sys, ln->tn_type->t_subt, ln, NULL); 1696 break; 1697 case PLUS: 1698 case MINUS: 1699 ntn = build_plus_minus(op, sys, ln, rn); 1700 break; 1701 case SHL: 1702 case SHR: 1703 ntn = build_bit_shift(op, sys, ln, rn); 1704 break; 1705 case COLON: 1706 ntn = build_colon(sys, ln, rn); 1707 break; 1708 case ASSIGN: 1709 case MULASS: 1710 case DIVASS: 1711 case MODASS: 1712 case ADDASS: 1713 case SUBASS: 1714 case SHLASS: 1715 case SHRASS: 1716 case ANDASS: 1717 case XORASS: 1718 case ORASS: 1719 case RETURN: 1720 case INIT: 1721 ntn = build_assignment(op, sys, ln, rn); 1722 break; 1723 case COMMA: 1724 case QUEST: 1725 ntn = new_tnode(op, sys, rn->tn_type, ln, rn); 1726 break; 1727 case REAL: 1728 case IMAG: 1729 ntn = build_real_imag(op, sys, ln); 1730 break; 1731 default: 1732 rettp = mp->m_returns_bool 1733 ? gettyp(Tflag ? BOOL : INT) : ln->tn_type; 1734 lint_assert(mp->m_binary == (rn != NULL)); 1735 ntn = new_tnode(op, sys, rettp, ln, rn); 1736 break; 1737 } 1738 1739 /* Return if an error occurred. */ 1740 if (ntn == NULL) 1741 return NULL; 1742 1743 /* Print a warning if precedence confusion is possible */ 1744 if (mp->m_possible_precedence_confusion) 1745 check_precedence_confusion(ntn); 1746 1747 /* 1748 * Print a warning if one of the operands is in a context where 1749 * it is compared with zero and if this operand is a constant. 1750 */ 1751 if (hflag && !constcond_flag && 1752 mp->m_compares_with_zero && 1753 (ln->tn_op == CON || 1754 ((mp->m_binary && op != QUEST) && rn->tn_op == CON)) && 1755 /* XXX: rn->tn_system_dependent should be checked as well */ 1756 !ln->tn_system_dependent) { 1757 /* constant in conditional context */ 1758 warning(161); 1759 } 1760 1761 /* Fold if the operator requires it */ 1762 if (mp->m_fold_constant_operands) { 1763 if (ln->tn_op == CON && (!mp->m_binary || rn->tn_op == CON)) { 1764 if (mp->m_compares_with_zero) { 1765 ntn = fold_bool(ntn); 1766 } else if (is_floating(ntn->tn_type->t_tspec)) { 1767 ntn = fold_float(ntn); 1768 } else { 1769 ntn = fold(ntn); 1770 } 1771 } else if (op == QUEST && ln->tn_op == CON) { 1772 ntn = ln->tn_val->v_quad != 0 1773 ? rn->tn_left : rn->tn_right; 1774 } 1775 } 1776 1777 return ntn; 1778 } 1779 1780 tnode_t * 1781 build_unary(op_t op, bool sys, tnode_t *tn) 1782 { 1783 return build_binary(tn, op, sys, NULL); 1784 } 1785 1786 /* 1787 * Return whether all struct/union members with the same name have the same 1788 * type and offset. 1789 */ 1790 static bool 1791 all_members_compatible(const sym_t *msym) 1792 { 1793 for (const sym_t *csym = msym; 1794 csym != NULL; csym = csym->s_symtab_next) { 1795 if (!is_member(csym)) 1796 continue; 1797 if (strcmp(msym->s_name, csym->s_name) != 0) 1798 continue; 1799 1800 for (const sym_t *sym = csym->s_symtab_next; 1801 sym != NULL; sym = sym->s_symtab_next) { 1802 1803 if (!is_member(sym)) 1804 continue; 1805 if (strcmp(csym->s_name, sym->s_name) != 0) 1806 continue; 1807 if (csym->u.s_member.sm_offset_in_bits != 1808 sym->u.s_member.sm_offset_in_bits) 1809 return false; 1810 1811 bool w = false; 1812 if (!types_compatible(csym->s_type, sym->s_type, 1813 false, false, &w) && !w) 1814 return false; 1815 if (csym->s_bitfield != sym->s_bitfield) 1816 return false; 1817 if (csym->s_bitfield) { 1818 type_t *tp1 = csym->s_type; 1819 type_t *tp2 = sym->s_type; 1820 if (tp1->t_flen != tp2->t_flen) 1821 return false; 1822 if (tp1->t_foffs != tp2->t_foffs) 1823 return false; 1824 } 1825 } 1826 } 1827 return true; 1828 } 1829 1830 /* 1831 * Returns a symbol which has the same name as the msym argument and is a 1832 * member of the struct or union specified by the tn argument. 1833 */ 1834 static sym_t * 1835 struct_or_union_member(tnode_t *tn, op_t op, sym_t *msym) 1836 { 1837 struct_or_union *str; 1838 type_t *tp; 1839 tspec_t t; 1840 1841 /* 1842 * Remove the member if it was unknown until now, which means 1843 * that no defined struct or union has a member with the same name. 1844 */ 1845 if (msym->s_scl == NOSCL) { 1846 /* type '%s' does not have member '%s' */ 1847 error(101, type_name(tn->tn_type), msym->s_name); 1848 rmsym(msym); 1849 msym->s_kind = FMEMBER; 1850 msym->s_scl = STRUCT_MEMBER; 1851 1852 struct_or_union *sou = expr_zero_alloc(sizeof(*sou)); 1853 sou->sou_tag = expr_zero_alloc(sizeof(*sou->sou_tag)); 1854 sou->sou_tag->s_name = unnamed; 1855 1856 msym->u.s_member.sm_sou_type = sou; 1857 /* 1858 * The member sm_offset_in_bits is not needed here since this 1859 * symbol can only be used for error reporting. 1860 */ 1861 return msym; 1862 } 1863 1864 /* Set str to the tag of which msym is expected to be a member. */ 1865 str = NULL; 1866 t = (tp = tn->tn_type)->t_tspec; 1867 if (op == POINT) { 1868 if (is_struct_or_union(t)) 1869 str = tp->t_str; 1870 } else if (op == ARROW && t == PTR) { 1871 t = (tp = tp->t_subt)->t_tspec; 1872 if (is_struct_or_union(t)) 1873 str = tp->t_str; 1874 } 1875 1876 /* 1877 * If this struct/union has a member with the name of msym, return it. 1878 */ 1879 if (str != NULL) { 1880 for (sym_t *sym = msym; 1881 sym != NULL; sym = sym->s_symtab_next) { 1882 if (!is_member(sym)) 1883 continue; 1884 if (sym->u.s_member.sm_sou_type != str) 1885 continue; 1886 if (strcmp(sym->s_name, msym->s_name) != 0) 1887 continue; 1888 return sym; 1889 } 1890 } 1891 1892 bool eq = all_members_compatible(msym); 1893 1894 /* 1895 * Now handle the case in which the left operand refers really 1896 * to a struct/union, but the right operand is not member of it. 1897 */ 1898 if (str != NULL) { 1899 if (eq && !allow_c90) { 1900 /* illegal use of member '%s' */ 1901 warning(102, msym->s_name); 1902 } else { 1903 /* illegal use of member '%s' */ 1904 error(102, msym->s_name); 1905 } 1906 return msym; 1907 } 1908 1909 /* 1910 * Now the left operand of ARROW does not point to a struct/union 1911 * or the left operand of POINT is no struct/union. 1912 */ 1913 if (eq) { 1914 if (op == POINT) { 1915 if (!allow_c90) { 1916 /* left operand of '.' must be struct ... */ 1917 warning(103, type_name(tn->tn_type)); 1918 } else { 1919 /* left operand of '.' must be struct ... */ 1920 error(103, type_name(tn->tn_type)); 1921 } 1922 } else { 1923 if (!allow_c90 && tn->tn_type->t_tspec == PTR) { 1924 /* left operand of '->' must be pointer ... */ 1925 warning(104, type_name(tn->tn_type)); 1926 } else { 1927 /* left operand of '->' must be pointer ... */ 1928 error(104, type_name(tn->tn_type)); 1929 } 1930 } 1931 } else { 1932 if (!allow_c90) { 1933 /* non-unique member requires struct/union %s */ 1934 error(105, op == POINT ? "object" : "pointer"); 1935 } else { 1936 /* unacceptable operand of '%s' */ 1937 error(111, op_name(op)); 1938 } 1939 } 1940 1941 return msym; 1942 } 1943 1944 tnode_t * 1945 build_member_access(tnode_t *ln, op_t op, bool sys, sbuf_t *member) 1946 { 1947 sym_t *msym; 1948 1949 if (ln == NULL) 1950 return NULL; 1951 1952 if (op == ARROW) { 1953 /* must do this before struct_or_union_member is called */ 1954 ln = cconv(ln); 1955 } 1956 msym = struct_or_union_member(ln, op, getsym(member)); 1957 return build_binary(ln, op, sys, build_name(msym, false)); 1958 } 1959 1960 /* 1961 * Perform class conversions. 1962 * 1963 * Arrays of type T are converted into pointers to type T. 1964 * Functions are converted to pointers to functions. 1965 * Lvalues are converted to rvalues. 1966 * 1967 * C99 6.3 "Conversions" 1968 * C99 6.3.2 "Other operands" 1969 * C99 6.3.2.1 "Lvalues, arrays, and function designators" 1970 */ 1971 tnode_t * 1972 cconv(tnode_t *tn) 1973 { 1974 type_t *tp; 1975 1976 /* 1977 * Array-lvalue (array of type T) is converted into rvalue 1978 * (pointer to type T) 1979 */ 1980 if (tn->tn_type->t_tspec == ARRAY) { 1981 if (!tn->tn_lvalue) { 1982 /* XXX print correct operator */ 1983 /* %soperand of '%s' must be lvalue */ 1984 gnuism(114, "", op_name(ADDR)); 1985 } 1986 tn = new_tnode(ADDR, tn->tn_sys, 1987 expr_derive_type(tn->tn_type->t_subt, PTR), tn, NULL); 1988 } 1989 1990 /* 1991 * Expression of type function (function with return value of type T) 1992 * in rvalue-expression (pointer to function with return value 1993 * of type T) 1994 */ 1995 if (tn->tn_type->t_tspec == FUNC) 1996 tn = build_address(tn->tn_sys, tn, true); 1997 1998 /* lvalue to rvalue */ 1999 if (tn->tn_lvalue) { 2000 tp = expr_dup_type(tn->tn_type); 2001 /* C99 6.3.2.1p2 sentence 2 says to remove the qualifiers. */ 2002 tp->t_const = tp->t_volatile = false; 2003 tn = new_tnode(LOAD, tn->tn_sys, tp, tn, NULL); 2004 } 2005 2006 return tn; 2007 } 2008 2009 const tnode_t * 2010 before_conversion(const tnode_t *tn) 2011 { 2012 while (tn->tn_op == CVT && !tn->tn_cast) 2013 tn = tn->tn_left; 2014 return tn; 2015 } 2016 2017 /* 2018 * Most errors required by ANSI C are reported in struct_or_union_member(). 2019 * Here we only check for totally wrong things. 2020 */ 2021 static bool 2022 typeok_point(const tnode_t *ln, const type_t *ltp, tspec_t lt) 2023 { 2024 if (is_struct_or_union(lt)) 2025 return true; 2026 2027 if (lt == FUNC || lt == VOID || ltp->t_bitfield) 2028 goto wrong; 2029 2030 /* 2031 * Some C dialects from before C90 tolerated any lvalue on the 2032 * left-hand side of the '.' operator, allowing things like 2033 * char st[100]; st.st_mtime, assuming that the member 'st_mtime' 2034 * only occurred in a single struct; see typeok_arrow. 2035 */ 2036 if (ln->tn_lvalue) 2037 return true; 2038 2039 wrong: 2040 /* With allow_c90 we already got an error */ 2041 if (!allow_c90) 2042 /* unacceptable operand of '%s' */ 2043 error(111, op_name(POINT)); 2044 2045 return false; 2046 } 2047 2048 static bool 2049 typeok_arrow(tspec_t lt) 2050 { 2051 /* 2052 * C1978 Appendix A 14.1 says: <quote>In fact, any lvalue is allowed 2053 * before '.', and that lvalue is then assumed to have the form of 2054 * the structure of which the name of the right is a member. [...] 2055 * Such constructions are non-portable.</quote> 2056 */ 2057 if (lt == PTR || (!allow_c90 && is_integer(lt))) 2058 return true; 2059 2060 /* With allow_c90 we already got an error */ 2061 if (!allow_c90) 2062 /* unacceptable operand of '%s' */ 2063 error(111, op_name(ARROW)); 2064 return false; 2065 } 2066 2067 static bool 2068 typeok_incdec(op_t op, const tnode_t *tn, const type_t *tp) 2069 { 2070 /* operand has scalar type (checked in typeok) */ 2071 if (!tn->tn_lvalue) { 2072 if (tn->tn_op == CVT && tn->tn_cast && 2073 tn->tn_left->tn_op == LOAD) { 2074 /* a cast does not yield an lvalue */ 2075 error(163); 2076 } 2077 /* %soperand of '%s' must be lvalue */ 2078 error(114, "", op_name(op)); 2079 return false; 2080 } else if (tp->t_const) { 2081 if (allow_c90) 2082 /* %soperand of '%s' must be modifiable lvalue */ 2083 warning(115, "", op_name(op)); 2084 } 2085 return true; 2086 } 2087 2088 static bool 2089 typeok_address(const mod_t *mp, 2090 const tnode_t *tn, const type_t *tp, tspec_t t) 2091 { 2092 if (t == ARRAY || t == FUNC) { 2093 /* ok, a warning comes later (in build_address()) */ 2094 } else if (!tn->tn_lvalue) { 2095 if (tn->tn_op == CVT && tn->tn_cast && 2096 tn->tn_left->tn_op == LOAD) { 2097 /* a cast does not yield an lvalue */ 2098 error(163); 2099 } 2100 /* %soperand of '%s' must be lvalue */ 2101 error(114, "", mp->m_name); 2102 return false; 2103 } else if (is_scalar(t)) { 2104 if (tp->t_bitfield) { 2105 /* cannot take address of bit-field */ 2106 error(112); 2107 return false; 2108 } 2109 } else if (t != STRUCT && t != UNION) { 2110 /* unacceptable operand of '%s' */ 2111 error(111, mp->m_name); 2112 return false; 2113 } 2114 if (tn->tn_op == NAME && tn->tn_sym->s_register) { 2115 /* cannot take address of register '%s' */ 2116 error(113, tn->tn_sym->s_name); 2117 return false; 2118 } 2119 return true; 2120 } 2121 2122 static bool 2123 typeok_indir(const type_t *tp, tspec_t t) 2124 { 2125 2126 if (t != PTR) { 2127 /* cannot dereference non-pointer type '%s' */ 2128 error(96, type_name(tp)); 2129 return false; 2130 } 2131 return true; 2132 } 2133 2134 /* 2135 * Called if incompatible types were detected. 2136 * Prints a appropriate warning. 2137 */ 2138 static void 2139 warn_incompatible_types(op_t op, 2140 const type_t *ltp, tspec_t lt, 2141 const type_t *rtp, tspec_t rt) 2142 { 2143 const mod_t *mp; 2144 2145 mp = &modtab[op]; 2146 2147 if (lt == VOID || (mp->m_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 (mp->m_binary) { 2154 /* operands of '%s' have incompatible types '%s' and '%s' */ 2155 error(107, mp->m_name, tspec_name(lt), tspec_name(rt)); 2156 } else { 2157 lint_assert(rt == NOTSPEC); 2158 /* operand of '%s' has invalid type '%s' */ 2159 error(108, mp->m_name, 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 if (!types_compatible(ltp->t_subt, rtp->t_subt, 2189 true, false, NULL)) { 2190 /* illegal pointer subtraction */ 2191 error(116); 2192 } 2193 } 2194 return true; 2195 } 2196 2197 static void 2198 typeok_shr(const mod_t *mp, 2199 const tnode_t *ln, tspec_t lt, 2200 const tnode_t *rn, tspec_t rt) 2201 { 2202 tspec_t olt, ort; 2203 2204 olt = before_conversion(ln)->tn_type->t_tspec; 2205 ort = before_conversion(rn)->tn_type->t_tspec; 2206 2207 /* operands have integer types (checked in typeok) */ 2208 if (pflag && !is_uinteger(olt)) { 2209 integer_constraints lc = ic_expr(ln); 2210 if (!ic_maybe_signed(ln->tn_type, &lc)) 2211 return; 2212 2213 /* 2214 * The left operand is signed. This means that 2215 * the operation is (possibly) nonportable. 2216 */ 2217 if (ln->tn_op != CON) { 2218 /* bitwise '%s' on signed value possibly nonportable */ 2219 warning(117, mp->m_name); 2220 } else if (ln->tn_val->v_quad < 0) { 2221 /* bitwise '%s' on signed value nonportable */ 2222 warning(120, mp->m_name); 2223 } 2224 } else if (allow_trad && allow_c90 && 2225 !is_uinteger(olt) && is_uinteger(ort)) { 2226 /* 2227 * The left operand would become unsigned in 2228 * traditional C. 2229 */ 2230 if (hflag && (ln->tn_op != CON || ln->tn_val->v_quad < 0)) { 2231 /* semantics of '%s' change in ANSI C; use ... */ 2232 warning(118, mp->m_name); 2233 } 2234 } else if (allow_trad && allow_c90 && 2235 !is_uinteger(olt) && !is_uinteger(ort) && 2236 portable_size_in_bits(lt) < portable_size_in_bits(rt)) { 2237 /* 2238 * In traditional C the left operand would be extended 2239 * (possibly sign-extended) and then shifted. 2240 */ 2241 if (hflag && (ln->tn_op != CON || ln->tn_val->v_quad < 0)) { 2242 /* semantics of '%s' change in ANSI C; use ... */ 2243 warning(118, mp->m_name); 2244 } 2245 } 2246 } 2247 2248 static void 2249 typeok_shl(const mod_t *mp, tspec_t lt, tspec_t rt) 2250 { 2251 /* 2252 * C90 does not perform balancing for shift operations, 2253 * but traditional C does. If the width of the right operand 2254 * is greater than the width of the left operand, then in 2255 * traditional C the left operand would be extended to the 2256 * width of the right operand. For SHL this may result in 2257 * different results. 2258 */ 2259 if (portable_size_in_bits(lt) < portable_size_in_bits(rt)) { 2260 /* 2261 * XXX If both operands are constant, make sure 2262 * that there is really a difference between 2263 * ANSI C and traditional C. 2264 */ 2265 if (hflag && !allow_c99) 2266 /* semantics of '%s' change in ANSI C; use ... */ 2267 warning(118, mp->m_name); 2268 } 2269 } 2270 2271 static void 2272 typeok_shift(const type_t *ltp, tspec_t lt, const tnode_t *rn, tspec_t rt) 2273 { 2274 if (rn->tn_op != CON) 2275 return; 2276 2277 if (!is_uinteger(rt) && rn->tn_val->v_quad < 0) { 2278 /* negative shift */ 2279 warning(121); 2280 } else if ((uint64_t)rn->tn_val->v_quad == 2281 (uint64_t)size_in_bits(lt)) { 2282 /* shift amount %u equals bit-size of '%s' */ 2283 warning(267, (unsigned)rn->tn_val->v_quad, type_name(ltp)); 2284 } else if ((uint64_t)rn->tn_val->v_quad > (uint64_t)size_in_bits(lt)) { 2285 /* shift amount %llu is greater than bit-size %llu of '%s' */ 2286 warning(122, (unsigned long long)rn->tn_val->v_quad, 2287 (unsigned long long)size_in_bits(lt), 2288 tspec_name(lt)); 2289 } 2290 } 2291 2292 static bool 2293 is_typeok_eq(const tnode_t *ln, tspec_t lt, const tnode_t *rn, tspec_t rt) 2294 { 2295 if (lt == PTR && is_null_pointer(rn)) 2296 return true; 2297 if (rt == PTR && is_null_pointer(ln)) 2298 return true; 2299 return false; 2300 } 2301 2302 /* 2303 * Called if incompatible pointer types are detected. 2304 * Print an appropriate warning. 2305 */ 2306 static void 2307 warn_incompatible_pointers(const mod_t *mp, 2308 const type_t *ltp, const type_t *rtp) 2309 { 2310 tspec_t lt, rt; 2311 2312 lint_assert(ltp->t_tspec == PTR); 2313 lint_assert(rtp->t_tspec == PTR); 2314 2315 lt = ltp->t_subt->t_tspec; 2316 rt = rtp->t_subt->t_tspec; 2317 2318 if (is_struct_or_union(lt) && is_struct_or_union(rt)) { 2319 if (mp == NULL) { 2320 /* illegal structure pointer combination */ 2321 warning(244); 2322 } else { 2323 /* incompatible structure pointers: '%s' '%s' '%s' */ 2324 warning(245, type_name(ltp), mp->m_name, type_name(rtp)); 2325 } 2326 } else { 2327 if (mp == NULL) { 2328 /* illegal combination of '%s' and '%s' */ 2329 warning(184, type_name(ltp), type_name(rtp)); 2330 } else { 2331 /* illegal combination of '%s' and '%s', op '%s' */ 2332 warning(124, 2333 type_name(ltp), type_name(rtp), mp->m_name); 2334 } 2335 } 2336 } 2337 2338 static void 2339 check_pointer_comparison(op_t op, const tnode_t *ln, const tnode_t *rn) 2340 { 2341 type_t *ltp, *rtp; 2342 tspec_t lst, rst; 2343 const char *lsts, *rsts; 2344 2345 lst = (ltp = ln->tn_type)->t_subt->t_tspec; 2346 rst = (rtp = rn->tn_type)->t_subt->t_tspec; 2347 2348 if (lst == VOID || rst == VOID) { 2349 /* TODO: C99 behaves like C90 here. */ 2350 if ((!allow_trad && !allow_c99) && 2351 (lst == FUNC || rst == FUNC)) { 2352 /* (void *)0 already handled in typeok() */ 2353 *(lst == FUNC ? &lsts : &rsts) = "function pointer"; 2354 *(lst == VOID ? &lsts : &rsts) = "'void *'"; 2355 /* ANSI C forbids comparison of %s with %s */ 2356 warning(274, lsts, rsts); 2357 } 2358 return; 2359 } 2360 2361 if (!types_compatible(ltp->t_subt, rtp->t_subt, true, false, NULL)) { 2362 warn_incompatible_pointers(&modtab[op], ltp, rtp); 2363 return; 2364 } 2365 2366 if (lst == FUNC && rst == FUNC) { 2367 /* TODO: C99 behaves like C90 here, see C99 6.5.8p2. */ 2368 if ((!allow_trad && !allow_c99) && op != EQ && op != NE) 2369 /* ANSI C forbids ordered comparisons of ... */ 2370 warning(125); 2371 } 2372 } 2373 2374 static bool 2375 typeok_compare(op_t op, 2376 const tnode_t *ln, const type_t *ltp, tspec_t lt, 2377 const tnode_t *rn, const type_t *rtp, tspec_t rt) 2378 { 2379 const char *lx, *rx; 2380 2381 if (lt == PTR && rt == PTR) { 2382 check_pointer_comparison(op, ln, rn); 2383 return true; 2384 } 2385 2386 if (lt != PTR && rt != PTR) 2387 return true; 2388 2389 if (!is_integer(lt) && !is_integer(rt)) { 2390 warn_incompatible_types(op, ltp, lt, rtp, rt); 2391 return false; 2392 } 2393 2394 lx = lt == PTR ? "pointer" : "integer"; 2395 rx = rt == PTR ? "pointer" : "integer"; 2396 /* illegal combination of %s '%s' and %s '%s', op '%s' */ 2397 warning(123, lx, type_name(ltp), rx, type_name(rtp), op_name(op)); 2398 return true; 2399 } 2400 2401 static bool 2402 typeok_quest(tspec_t lt, const tnode_t *rn) 2403 { 2404 if (!is_scalar(lt)) { 2405 /* first operand must have scalar type, op ? : */ 2406 error(170); 2407 return false; 2408 } 2409 lint_assert(before_conversion(rn)->tn_op == COLON); 2410 return true; 2411 } 2412 2413 static void 2414 typeok_colon_pointer(const mod_t *mp, const type_t *ltp, const type_t *rtp) 2415 { 2416 type_t *lstp = ltp->t_subt; 2417 type_t *rstp = rtp->t_subt; 2418 tspec_t lst = lstp->t_tspec; 2419 tspec_t rst = rstp->t_tspec; 2420 2421 if ((lst == VOID && rst == FUNC) || (lst == FUNC && rst == VOID)) { 2422 /* (void *)0 is handled in typeok_colon */ 2423 /* TODO: C99 behaves like C90 here. */ 2424 if (!allow_trad && !allow_c99) 2425 /* ANSI C forbids conversion of %s to %s, op %s */ 2426 warning(305, "function pointer", "'void *'", 2427 mp->m_name); 2428 return; 2429 } 2430 2431 if (pointer_types_are_compatible(lstp, rstp, true)) 2432 return; 2433 if (!types_compatible(lstp, rstp, true, false, NULL)) 2434 warn_incompatible_pointers(mp, ltp, rtp); 2435 } 2436 2437 static bool 2438 typeok_colon(const mod_t *mp, 2439 const tnode_t *ln, const type_t *ltp, tspec_t lt, 2440 const tnode_t *rn, const type_t *rtp, tspec_t rt) 2441 { 2442 2443 if (is_arithmetic(lt) && is_arithmetic(rt)) 2444 return true; 2445 if (lt == BOOL && rt == BOOL) 2446 return true; 2447 2448 if (lt == STRUCT && rt == STRUCT && ltp->t_str == rtp->t_str) 2449 return true; 2450 if (lt == UNION && rt == UNION && ltp->t_str == rtp->t_str) 2451 return true; 2452 2453 if (lt == PTR && is_null_pointer(rn)) 2454 return true; 2455 if (rt == PTR && is_null_pointer(ln)) 2456 return true; 2457 2458 if ((lt == PTR && is_integer(rt)) || (is_integer(lt) && rt == PTR)) { 2459 const char *lx = lt == PTR ? "pointer" : "integer"; 2460 const char *rx = rt == PTR ? "pointer" : "integer"; 2461 /* illegal combination of %s '%s' and %s '%s', op '%s' */ 2462 warning(123, lx, type_name(ltp), 2463 rx, type_name(rtp), mp->m_name); 2464 return true; 2465 } 2466 2467 if (lt == VOID || rt == VOID) { 2468 if (lt != VOID || rt != VOID) 2469 /* incompatible types '%s' and '%s' in conditional */ 2470 warning(126, type_name(ltp), type_name(rtp)); 2471 return true; 2472 } 2473 2474 if (lt == PTR && rt == PTR) { 2475 typeok_colon_pointer(mp, ltp, rtp); 2476 return true; 2477 } 2478 2479 /* incompatible types '%s' and '%s' in conditional */ 2480 error(126, type_name(ltp), type_name(rtp)); 2481 return false; 2482 } 2483 2484 /* 2485 * Returns true if the given structure or union has a constant member 2486 * (maybe recursively). 2487 */ 2488 static bool 2489 has_constant_member(const type_t *tp) 2490 { 2491 sym_t *m; 2492 2493 lint_assert(is_struct_or_union(tp->t_tspec)); 2494 2495 for (m = tp->t_str->sou_first_member; m != NULL; m = m->s_next) { 2496 const type_t *mtp = m->s_type; 2497 if (mtp->t_const) 2498 return true; 2499 if (is_struct_or_union(mtp->t_tspec) && 2500 has_constant_member(mtp)) 2501 return true; 2502 } 2503 return false; 2504 } 2505 2506 static bool 2507 typeok_assign(op_t op, const tnode_t *ln, const type_t *ltp, tspec_t lt) 2508 { 2509 if (op == RETURN || op == INIT || op == FARG) 2510 return true; 2511 2512 if (!ln->tn_lvalue) { 2513 if (ln->tn_op == CVT && ln->tn_cast && 2514 ln->tn_left->tn_op == LOAD) { 2515 /* a cast does not yield an lvalue */ 2516 error(163); 2517 } 2518 /* %soperand of '%s' must be lvalue */ 2519 error(114, "left ", op_name(op)); 2520 return false; 2521 } else if (ltp->t_const || (is_struct_or_union(lt) && 2522 has_constant_member(ltp))) { 2523 if (allow_c90) 2524 /* %soperand of '%s' must be modifiable lvalue */ 2525 warning(115, "left ", op_name(op)); 2526 } 2527 return true; 2528 } 2529 2530 /* Check the types using the information from modtab[]. */ 2531 static bool 2532 typeok_scalar(op_t op, const mod_t *mp, 2533 const type_t *ltp, tspec_t lt, 2534 const type_t *rtp, tspec_t rt) 2535 { 2536 if (mp->m_takes_bool && lt == BOOL && rt == BOOL) 2537 return true; 2538 if (mp->m_requires_integer) { 2539 if (!is_integer(lt) || (mp->m_binary && !is_integer(rt))) { 2540 warn_incompatible_types(op, ltp, lt, rtp, rt); 2541 return false; 2542 } 2543 } else if (mp->m_requires_integer_or_complex) { 2544 if ((!is_integer(lt) && !is_complex(lt)) || 2545 (mp->m_binary && (!is_integer(rt) && !is_complex(rt)))) { 2546 warn_incompatible_types(op, ltp, lt, rtp, rt); 2547 return false; 2548 } 2549 } else if (mp->m_requires_scalar) { 2550 if (!is_scalar(lt) || (mp->m_binary && !is_scalar(rt))) { 2551 warn_incompatible_types(op, ltp, lt, rtp, rt); 2552 return false; 2553 } 2554 } else if (mp->m_requires_arith) { 2555 if (!is_arithmetic(lt) || 2556 (mp->m_binary && !is_arithmetic(rt))) { 2557 warn_incompatible_types(op, ltp, lt, rtp, rt); 2558 return false; 2559 } 2560 } 2561 return true; 2562 } 2563 2564 static void 2565 check_assign_void_pointer(op_t op, int arg, 2566 tspec_t lt, tspec_t lst, 2567 tspec_t rt, tspec_t rst) 2568 { 2569 const char *lts, *rts; 2570 2571 if (!(lt == PTR && rt == PTR && (lst == VOID || rst == VOID))) 2572 return; 2573 /* two pointers, at least one pointer to void */ 2574 2575 /* TODO: C99 behaves like C90 here. */ 2576 if (!((!allow_trad && !allow_c99) && (lst == FUNC || rst == FUNC))) 2577 return; 2578 /* comb. of ptr to func and ptr to void */ 2579 2580 *(lst == FUNC ? <s : &rts) = "function pointer"; 2581 *(lst == VOID ? <s : &rts) = "'void *'"; 2582 2583 switch (op) { 2584 case INIT: 2585 case RETURN: 2586 /* ANSI C forbids conversion of %s to %s */ 2587 warning(303, rts, lts); 2588 break; 2589 case FARG: 2590 /* ANSI C forbids conversion of %s to %s, arg #%d */ 2591 warning(304, rts, lts, arg); 2592 break; 2593 default: 2594 /* ANSI C forbids conversion of %s to %s, op %s */ 2595 warning(305, rts, lts, op_name(op)); 2596 break; 2597 } 2598 } 2599 2600 static bool 2601 is_direct_function_call(const tnode_t *tn, const char **out_name) 2602 { 2603 2604 if (!(tn->tn_op == CALL && 2605 tn->tn_left->tn_op == ADDR && 2606 tn->tn_left->tn_left->tn_op == NAME)) 2607 return false; 2608 2609 *out_name = tn->tn_left->tn_left->tn_sym->s_name; 2610 return true; 2611 } 2612 2613 static bool 2614 is_unconst_function(const char *name) 2615 { 2616 2617 return strcmp(name, "memchr") == 0 || 2618 strcmp(name, "strchr") == 0 || 2619 strcmp(name, "strpbrk") == 0 || 2620 strcmp(name, "strrchr") == 0 || 2621 strcmp(name, "strstr") == 0; 2622 } 2623 2624 static bool 2625 is_const_char_pointer(const tnode_t *tn) 2626 { 2627 const type_t *tp; 2628 2629 /* 2630 * For traditional reasons, C99 6.4.5p5 defines that string literals 2631 * have type 'char[]'. They are often implicitly converted to 2632 * 'char *', for example when they are passed as function arguments. 2633 * 2634 * C99 6.4.5p6 further defines that modifying a string that is 2635 * constructed from a string literal invokes undefined behavior. 2636 * 2637 * Out of these reasons, string literals are treated as 'effectively 2638 * const' here. 2639 */ 2640 if (tn->tn_op == CVT && 2641 tn->tn_left->tn_op == ADDR && 2642 tn->tn_left->tn_left->tn_op == STRING) 2643 return true; 2644 2645 tp = before_conversion(tn)->tn_type; 2646 return tp->t_tspec == PTR && 2647 tp->t_subt->t_tspec == CHAR && 2648 tp->t_subt->t_const; 2649 } 2650 2651 static bool 2652 is_first_arg_const_char_pointer(const tnode_t *tn) 2653 { 2654 const tnode_t *an; 2655 2656 an = tn->tn_right; 2657 if (an == NULL) 2658 return false; 2659 2660 while (an->tn_right != NULL) 2661 an = an->tn_right; 2662 return is_const_char_pointer(an->tn_left); 2663 } 2664 2665 static bool 2666 is_const_pointer(const tnode_t *tn) 2667 { 2668 const type_t *tp; 2669 2670 tp = before_conversion(tn)->tn_type; 2671 return tp->t_tspec == PTR && tp->t_subt->t_const; 2672 } 2673 2674 static bool 2675 is_second_arg_const_pointer(const tnode_t *tn) 2676 { 2677 const tnode_t *an; 2678 2679 an = tn->tn_right; 2680 if (an == NULL || an->tn_right == NULL) 2681 return false; 2682 2683 while (an->tn_right->tn_right != NULL) 2684 an = an->tn_right; 2685 return is_const_pointer(an->tn_left); 2686 } 2687 2688 static void 2689 check_unconst_function(const type_t *lstp, const tnode_t *rn) 2690 { 2691 const char *function_name; 2692 2693 if (lstp->t_tspec == CHAR && !lstp->t_const && 2694 is_direct_function_call(rn, &function_name) && 2695 is_unconst_function(function_name) && 2696 is_first_arg_const_char_pointer(rn)) { 2697 /* call to '%s' effectively discards 'const' from argument */ 2698 warning(346, function_name); 2699 } 2700 2701 if (!lstp->t_const && 2702 is_direct_function_call(rn, &function_name) && 2703 strcmp(function_name, "bsearch") == 0 && 2704 is_second_arg_const_pointer(rn)) { 2705 /* call to '%s' effectively discards 'const' from argument */ 2706 warning(346, function_name); 2707 } 2708 } 2709 2710 static bool 2711 check_assign_void_pointer_compat(op_t op, int arg, 2712 const type_t *const ltp, tspec_t const lt, 2713 const type_t *const lstp, tspec_t const lst, 2714 const tnode_t *const rn, 2715 const type_t *const rtp, tspec_t const rt, 2716 const type_t *const rstp, tspec_t const rst) 2717 { 2718 if (!(lt == PTR && rt == PTR && (lst == VOID || rst == VOID || 2719 types_compatible(lstp, rstp, 2720 true, false, NULL)))) 2721 return false; 2722 2723 /* compatible pointer types (qualifiers ignored) */ 2724 if (allow_c90 && 2725 ((!lstp->t_const && rstp->t_const) || 2726 (!lstp->t_volatile && rstp->t_volatile))) { 2727 /* left side has not all qualifiers of right */ 2728 switch (op) { 2729 case INIT: 2730 case RETURN: 2731 /* incompatible pointer types to '%s' and '%s' */ 2732 warning(182, type_name(lstp), type_name(rstp)); 2733 break; 2734 case FARG: 2735 /* converting '%s' to incompatible '%s' ... */ 2736 warning(153, 2737 type_name(rtp), type_name(ltp), arg); 2738 break; 2739 default: 2740 /* operands of '%s' have incompatible pointer ... */ 2741 warning(128, op_name(op), 2742 type_name(lstp), type_name(rstp)); 2743 break; 2744 } 2745 } 2746 2747 if (allow_c90) 2748 check_unconst_function(lstp, rn); 2749 2750 return true; 2751 } 2752 2753 static bool 2754 check_assign_pointer_integer(op_t op, int arg, 2755 const type_t *const ltp, tspec_t const lt, 2756 const type_t *const rtp, tspec_t const rt) 2757 { 2758 const char *lx, *rx; 2759 2760 if (!((lt == PTR && is_integer(rt)) || (is_integer(lt) && rt == PTR))) 2761 return false; 2762 2763 lx = lt == PTR ? "pointer" : "integer"; 2764 rx = rt == PTR ? "pointer" : "integer"; 2765 2766 switch (op) { 2767 case INIT: 2768 case RETURN: 2769 /* illegal combination of %s '%s' and %s '%s' */ 2770 warning(183, lx, type_name(ltp), rx, type_name(rtp)); 2771 break; 2772 case FARG: 2773 /* illegal combination of %s '%s' and %s '%s', arg #%d */ 2774 warning(154, 2775 lx, type_name(ltp), rx, type_name(rtp), arg); 2776 break; 2777 default: 2778 /* illegal combination of %s '%s' and %s '%s', op '%s' */ 2779 warning(123, 2780 lx, type_name(ltp), rx, type_name(rtp), op_name(op)); 2781 break; 2782 } 2783 return true; 2784 } 2785 2786 static bool 2787 check_assign_pointer(op_t op, int arg, 2788 const type_t *ltp, tspec_t lt, 2789 const type_t *rtp, tspec_t rt) 2790 { 2791 if (!(lt == PTR && rt == PTR)) 2792 return false; 2793 2794 switch (op) { 2795 case RETURN: 2796 warn_incompatible_pointers(NULL, ltp, rtp); 2797 break; 2798 case FARG: 2799 /* converting '%s' to incompatible '%s' for ... */ 2800 warning(153, type_name(rtp), type_name(ltp), arg); 2801 break; 2802 default: 2803 warn_incompatible_pointers(&modtab[op], ltp, rtp); 2804 break; 2805 } 2806 return true; 2807 } 2808 2809 static void 2810 warn_assign(op_t op, int arg, 2811 const type_t *ltp, tspec_t lt, 2812 const type_t *rtp, tspec_t rt) 2813 { 2814 switch (op) { 2815 case INIT: 2816 /* cannot initialize '%s' from '%s' */ 2817 error(185, type_name(ltp), type_name(rtp)); 2818 break; 2819 case RETURN: 2820 /* function has return type '%s' but returns '%s' */ 2821 error(211, type_name(ltp), type_name(rtp)); 2822 break; 2823 case FARG: 2824 /* passing '%s' to incompatible '%s', arg #%d */ 2825 warning(155, type_name(rtp), type_name(ltp), arg); 2826 break; 2827 default: 2828 warn_incompatible_types(op, ltp, lt, rtp, rt); 2829 break; 2830 } 2831 } 2832 2833 /* 2834 * Checks type compatibility for ASSIGN, INIT, FARG and RETURN 2835 * and prints warnings/errors if necessary. 2836 * Returns whether the types are (almost) compatible. 2837 */ 2838 static bool 2839 check_assign_types_compatible(op_t op, int arg, 2840 const tnode_t *ln, const tnode_t *rn) 2841 { 2842 tspec_t lt, rt, lst = NOTSPEC, rst = NOTSPEC; 2843 type_t *ltp, *rtp, *lstp = NULL, *rstp = NULL; 2844 2845 if ((lt = (ltp = ln->tn_type)->t_tspec) == PTR) 2846 lst = (lstp = ltp->t_subt)->t_tspec; 2847 if ((rt = (rtp = rn->tn_type)->t_tspec) == PTR) 2848 rst = (rstp = rtp->t_subt)->t_tspec; 2849 2850 if (lt == BOOL && is_scalar(rt)) /* C99 6.3.1.2 */ 2851 return true; 2852 2853 if (is_arithmetic(lt) && (is_arithmetic(rt) || rt == BOOL)) 2854 return true; 2855 2856 if (is_struct_or_union(lt) && is_struct_or_union(rt)) 2857 /* both are struct or union */ 2858 return ltp->t_str == rtp->t_str; 2859 2860 /* a null pointer may be assigned to any pointer */ 2861 if (lt == PTR && is_null_pointer(rn)) 2862 return true; 2863 2864 check_assign_void_pointer(op, arg, lt, lst, rt, rst); 2865 2866 if (check_assign_void_pointer_compat(op, arg, 2867 ltp, lt, lstp, lst, rn, rtp, rt, rstp, rst)) 2868 return true; 2869 2870 if (check_assign_pointer_integer(op, arg, ltp, lt, rtp, rt)) 2871 return true; 2872 2873 if (check_assign_pointer(op, arg, ltp, lt, rtp, rt)) 2874 return true; 2875 2876 warn_assign(op, arg, ltp, lt, rtp, rt); 2877 return false; 2878 } 2879 2880 static bool 2881 has_side_effect(const tnode_t *tn) /* NOLINT(misc-no-recursion) */ 2882 { 2883 op_t op = tn->tn_op; 2884 2885 if (modtab[op].m_has_side_effect) 2886 return true; 2887 2888 if (op == CVT && tn->tn_type->t_tspec == VOID) 2889 return has_side_effect(tn->tn_left); 2890 2891 /* XXX: Why not has_side_effect(tn->tn_left) as well? */ 2892 if (op == LOGAND || op == LOGOR) 2893 return has_side_effect(tn->tn_right); 2894 2895 /* XXX: Why not has_side_effect(tn->tn_left) as well? */ 2896 if (op == QUEST) 2897 return has_side_effect(tn->tn_right); 2898 2899 if (op == COLON || op == COMMA) { 2900 return has_side_effect(tn->tn_left) || 2901 has_side_effect(tn->tn_right); 2902 } 2903 2904 return false; 2905 } 2906 2907 static bool 2908 is_void_cast(const tnode_t *tn) 2909 { 2910 2911 return tn->tn_op == CVT && tn->tn_cast && 2912 tn->tn_type->t_tspec == VOID; 2913 } 2914 2915 static bool 2916 is_local_symbol(const tnode_t *tn) 2917 { 2918 2919 return tn->tn_op == LOAD && 2920 tn->tn_left->tn_op == NAME && 2921 tn->tn_left->tn_sym->s_scl == AUTO; 2922 } 2923 2924 static bool 2925 is_int_constant_zero(const tnode_t *tn) 2926 { 2927 2928 return tn->tn_op == CON && 2929 tn->tn_type->t_tspec == INT && 2930 tn->tn_val->v_quad == 0; 2931 } 2932 2933 static void 2934 check_null_effect(const tnode_t *tn) 2935 { 2936 2937 if (!hflag) 2938 return; 2939 if (has_side_effect(tn)) 2940 return; 2941 if (is_void_cast(tn) && is_local_symbol(tn->tn_left)) 2942 return; 2943 if (is_void_cast(tn) && is_int_constant_zero(tn->tn_left)) 2944 return; 2945 2946 /* expression has null effect */ 2947 warning(129); 2948 } 2949 2950 /* 2951 * Check the types for specific operators and type combinations. 2952 * 2953 * At this point, the operands already conform to the type requirements of 2954 * the operator, such as being integer, floating or scalar. 2955 */ 2956 static bool 2957 typeok_op(op_t op, const mod_t *mp, int arg, 2958 const tnode_t *ln, const type_t *ltp, tspec_t lt, 2959 const tnode_t *rn, const type_t *rtp, tspec_t rt) 2960 { 2961 switch (op) { 2962 case ARROW: 2963 return typeok_arrow(lt); 2964 case POINT: 2965 return typeok_point(ln, ltp, lt); 2966 case INCBEF: 2967 case DECBEF: 2968 case INCAFT: 2969 case DECAFT: 2970 return typeok_incdec(op, ln, ltp); 2971 case INDIR: 2972 return typeok_indir(ltp, lt); 2973 case ADDR: 2974 return typeok_address(mp, ln, ltp, lt); 2975 case PLUS: 2976 return typeok_plus(op, ltp, lt, rtp, rt); 2977 case MINUS: 2978 return typeok_minus(op, ltp, lt, rtp, rt); 2979 case SHL: 2980 typeok_shl(mp, lt, rt); 2981 goto shift; 2982 case SHR: 2983 typeok_shr(mp, ln, lt, rn, rt); 2984 shift: 2985 typeok_shift(ltp, lt, rn, rt); 2986 break; 2987 case LT: 2988 case LE: 2989 case GT: 2990 case GE: 2991 compare: 2992 return typeok_compare(op, ln, ltp, lt, rn, rtp, rt); 2993 case EQ: 2994 case NE: 2995 if (is_typeok_eq(ln, lt, rn, rt)) 2996 break; 2997 goto compare; 2998 case QUEST: 2999 return typeok_quest(lt, rn); 3000 case COLON: 3001 return typeok_colon(mp, ln, ltp, lt, rn, rtp, rt); 3002 case ASSIGN: 3003 case INIT: 3004 case FARG: 3005 case RETURN: 3006 if (!check_assign_types_compatible(op, arg, ln, rn)) 3007 return false; 3008 goto assign; 3009 case MULASS: 3010 case DIVASS: 3011 case MODASS: 3012 goto assign; 3013 case ADDASS: 3014 case SUBASS: 3015 if ((lt == PTR && !is_integer(rt)) || rt == PTR) { 3016 warn_incompatible_types(op, ltp, lt, rtp, rt); 3017 return false; 3018 } 3019 goto assign; 3020 case SHLASS: 3021 goto assign; 3022 case SHRASS: 3023 if (pflag && !is_uinteger(lt) && 3024 !(!allow_c90 && is_uinteger(rt))) { 3025 /* bitwise '%s' on signed value possibly nonportable */ 3026 warning(117, mp->m_name); 3027 } 3028 goto assign; 3029 case ANDASS: 3030 case XORASS: 3031 case ORASS: 3032 assign: 3033 return typeok_assign(op, ln, ltp, lt); 3034 case COMMA: 3035 if (!modtab[ln->tn_op].m_has_side_effect) 3036 check_null_effect(ln); 3037 break; 3038 default: 3039 break; 3040 } 3041 return true; 3042 } 3043 3044 /* Prints a warning if a strange operator is used on an enum type. */ 3045 static void 3046 check_bad_enum_operation(op_t op, const tnode_t *ln, const tnode_t *rn) 3047 { 3048 3049 if (!eflag) 3050 return; 3051 3052 /* 3053 * Enum as offset to a pointer is an exception (otherwise enums 3054 * could not be used as array indices). 3055 */ 3056 if (op == PLUS && 3057 ((ln->tn_type->t_is_enum && rn->tn_type->t_tspec == PTR) || 3058 (rn->tn_type->t_is_enum && ln->tn_type->t_tspec == PTR))) { 3059 return; 3060 } 3061 3062 /* dubious operation on enum, op '%s' */ 3063 warning(241, op_name(op)); 3064 } 3065 3066 /* 3067 * Prints a warning if an operator is applied to two different enum types. 3068 */ 3069 static void 3070 check_enum_type_mismatch(op_t op, int arg, const tnode_t *ln, const tnode_t *rn) 3071 { 3072 const mod_t *mp; 3073 3074 mp = &modtab[op]; 3075 3076 if (ln->tn_type->t_enum != rn->tn_type->t_enum) { 3077 switch (op) { 3078 case INIT: 3079 /* enum type mismatch between '%s' and '%s' in ... */ 3080 warning(210, 3081 type_name(ln->tn_type), type_name(rn->tn_type)); 3082 break; 3083 case FARG: 3084 /* function expects '%s', passing '%s' for arg #%d */ 3085 warning(156, 3086 type_name(ln->tn_type), type_name(rn->tn_type), 3087 arg); 3088 break; 3089 case RETURN: 3090 /* function has return type '%s' but returns '%s' */ 3091 warning(211, 3092 type_name(ln->tn_type), type_name(rn->tn_type)); 3093 break; 3094 default: 3095 /* enum type mismatch: '%s' '%s' '%s' */ 3096 warning(130, type_name(ln->tn_type), mp->m_name, 3097 type_name(rn->tn_type)); 3098 break; 3099 } 3100 } else if (Pflag && mp->m_comparison && op != EQ && op != NE) { 3101 if (eflag) 3102 /* dubious comparison of enums, op '%s' */ 3103 warning(243, mp->m_name); 3104 } 3105 } 3106 3107 /* Prints a warning if the operands mix between enum and integer. */ 3108 static void 3109 check_enum_int_mismatch(op_t op, int arg, const tnode_t *ln, const tnode_t *rn) 3110 { 3111 3112 if (!eflag) 3113 return; 3114 3115 switch (op) { 3116 case INIT: 3117 /* 3118 * Initialization with 0 is allowed. Otherwise, all implicit 3119 * initializations would need to be warned upon as well. 3120 */ 3121 if (!rn->tn_type->t_is_enum && rn->tn_op == CON && 3122 is_integer(rn->tn_type->t_tspec) && 3123 rn->tn_val->v_quad == 0) { 3124 return; 3125 } 3126 /* initialization of '%s' with '%s' */ 3127 warning(277, type_name(ln->tn_type), type_name(rn->tn_type)); 3128 break; 3129 case FARG: 3130 /* combination of '%s' and '%s', arg #%d */ 3131 warning(278, 3132 type_name(ln->tn_type), type_name(rn->tn_type), arg); 3133 break; 3134 case RETURN: 3135 /* combination of '%s' and '%s' in return */ 3136 warning(279, type_name(ln->tn_type), type_name(rn->tn_type)); 3137 break; 3138 default: 3139 /* combination of '%s' and '%s', op '%s' */ 3140 warning(242, type_name(ln->tn_type), type_name(rn->tn_type), 3141 op_name(op)); 3142 break; 3143 } 3144 } 3145 3146 static void 3147 typeok_enum(op_t op, const mod_t *mp, int arg, 3148 const tnode_t *ln, const type_t *ltp, 3149 const tnode_t *rn, const type_t *rtp) 3150 { 3151 if (mp->m_bad_on_enum && 3152 (ltp->t_is_enum || (mp->m_binary && rtp->t_is_enum))) { 3153 check_bad_enum_operation(op, ln, rn); 3154 } else if (mp->m_valid_on_enum && 3155 (ltp->t_is_enum && rtp != NULL && rtp->t_is_enum)) { 3156 check_enum_type_mismatch(op, arg, ln, rn); 3157 } else if (mp->m_valid_on_enum && 3158 (ltp->t_is_enum || (rtp != NULL && rtp->t_is_enum))) { 3159 check_enum_int_mismatch(op, arg, ln, rn); 3160 } 3161 } 3162 3163 /* Perform most type checks. Return whether the types are ok. */ 3164 bool 3165 typeok(op_t op, int arg, const tnode_t *ln, const tnode_t *rn) 3166 { 3167 const mod_t *mp; 3168 tspec_t lt, rt; 3169 type_t *ltp, *rtp; 3170 3171 mp = &modtab[op]; 3172 3173 lint_assert((ltp = ln->tn_type) != NULL); 3174 lt = ltp->t_tspec; 3175 3176 if (mp->m_binary) { 3177 lint_assert((rtp = rn->tn_type) != NULL); 3178 rt = rtp->t_tspec; 3179 } else { 3180 rtp = NULL; 3181 rt = NOTSPEC; 3182 } 3183 3184 if (Tflag && !typeok_scalar_strict_bool(op, mp, arg, ln, rn)) 3185 return false; 3186 if (!typeok_scalar(op, mp, ltp, lt, rtp, rt)) 3187 return false; 3188 3189 if (!typeok_op(op, mp, arg, ln, ltp, lt, rn, rtp, rt)) 3190 return false; 3191 3192 typeok_enum(op, mp, arg, ln, ltp, rn, rtp); 3193 return true; 3194 } 3195 3196 /* In traditional C, keep unsigned and promote FLOAT to DOUBLE. */ 3197 static tspec_t 3198 promote_trad(tspec_t t) 3199 { 3200 3201 if (t == UCHAR || t == USHORT) 3202 return UINT; 3203 if (t == CHAR || t == SCHAR || t == SHORT) 3204 return INT; 3205 if (t == FLOAT) 3206 return DOUBLE; 3207 if (t == ENUM) 3208 return INT; 3209 return t; 3210 } 3211 3212 /* 3213 * C99 6.3.1.1p2 requires for types with lower rank than int that "If an int 3214 * can represent all the values of the original type, the value is converted 3215 * to an int; otherwise it is converted to an unsigned int", and that "All 3216 * other types are unchanged by the integer promotions". 3217 */ 3218 static tspec_t 3219 promote_c90(const tnode_t *tn, tspec_t t, bool farg) 3220 { 3221 if (tn->tn_type->t_bitfield) { 3222 unsigned int len = tn->tn_type->t_flen; 3223 if (len < size_in_bits(INT)) 3224 return INT; 3225 if (len == size_in_bits(INT)) 3226 return is_uinteger(t) ? UINT : INT; 3227 return t; 3228 } 3229 3230 if (t == CHAR || t == SCHAR) 3231 return INT; 3232 if (t == UCHAR) 3233 return size_in_bits(CHAR) < size_in_bits(INT) ? INT : UINT; 3234 if (t == SHORT) 3235 return INT; 3236 if (t == USHORT) 3237 return size_in_bits(SHORT) < size_in_bits(INT) ? INT : UINT; 3238 if (t == ENUM) 3239 return INT; 3240 if (farg && t == FLOAT) 3241 return DOUBLE; 3242 return t; 3243 } 3244 3245 /* 3246 * Performs the "integer promotions" (C99 6.3.1.1p2), which convert small 3247 * integer types to either int or unsigned int. 3248 * 3249 * If allow_c90 is unset or the operand is a function argument with no type 3250 * information (no prototype or variable # of args), converts float to double. 3251 */ 3252 tnode_t * 3253 promote(op_t op, bool farg, tnode_t *tn) 3254 { 3255 3256 tspec_t ot = tn->tn_type->t_tspec; 3257 if (!is_arithmetic(ot)) 3258 return tn; 3259 3260 tspec_t nt = allow_c90 ? promote_c90(tn, ot, farg) : promote_trad(ot); 3261 if (nt == ot) 3262 return tn; 3263 3264 type_t *ntp = expr_dup_type(tn->tn_type); 3265 ntp->t_tspec = nt; 3266 /* 3267 * Keep t_is_enum even though t_tspec gets converted from 3268 * ENUM to INT, so we are later able to check compatibility 3269 * of enum types. 3270 */ 3271 return convert(op, 0, ntp, tn); 3272 } 3273 3274 static void 3275 convert_integer_from_floating(op_t op, const type_t *tp, const tnode_t *tn) 3276 { 3277 3278 if (op == CVT) 3279 /* cast from floating point '%s' to integer '%s' */ 3280 query_message(2, type_name(tn->tn_type), type_name(tp)); 3281 else 3282 /* implicit conversion from floating point '%s' to ... */ 3283 query_message(1, type_name(tn->tn_type), type_name(tp)); 3284 } 3285 3286 static bool 3287 should_warn_about_prototype_conversion(tspec_t nt, 3288 tspec_t ot, const tnode_t *ptn) 3289 { 3290 3291 if (nt == ot) 3292 return false; 3293 3294 if (nt == ENUM && ot == INT) 3295 return false; 3296 3297 if (is_floating(nt) != is_floating(ot) || 3298 portable_size_in_bits(nt) != portable_size_in_bits(ot)) { 3299 /* representation and/or width change */ 3300 if (!is_integer(ot)) 3301 return true; 3302 /* 3303 * XXX: Investigate whether this rule makes sense; see 3304 * tests/usr.bin/xlint/lint1/platform_long.c. 3305 */ 3306 return portable_size_in_bits(ot) > portable_size_in_bits(INT); 3307 } 3308 3309 if (!hflag) 3310 return false; 3311 3312 /* 3313 * If the types differ only in sign and the argument has the same 3314 * representation in both types, print no warning. 3315 */ 3316 if (ptn->tn_op == CON && is_integer(nt) && 3317 signed_type(nt) == signed_type(ot) && 3318 !msb(ptn->tn_val->v_quad, ot)) 3319 return false; 3320 3321 return true; 3322 } 3323 3324 /* 3325 * Warn if a prototype causes a type conversion that is different from what 3326 * would happen to the same argument in the absence of a prototype. This 3327 * check is intended for code that needs to stay compatible with pre-C90 C. 3328 * 3329 * Errors/warnings about illegal type combinations are already printed 3330 * in check_assign_types_compatible(). 3331 */ 3332 static void 3333 check_prototype_conversion(int arg, tspec_t nt, tspec_t ot, type_t *tp, 3334 tnode_t *tn) 3335 { 3336 tnode_t *ptn; 3337 3338 if (!is_arithmetic(nt) || !is_arithmetic(ot)) 3339 return; 3340 3341 /* 3342 * If the type of the formal parameter is char/short, a warning 3343 * would be useless, because functions declared the old style 3344 * can't expect char/short arguments. 3345 */ 3346 if (nt == CHAR || nt == SCHAR || nt == UCHAR || 3347 nt == SHORT || nt == USHORT) 3348 return; 3349 3350 /* apply the default promotion */ 3351 ptn = promote(NOOP, true, tn); 3352 ot = ptn->tn_type->t_tspec; 3353 3354 if (should_warn_about_prototype_conversion(nt, ot, ptn)) { 3355 /* argument #%d is converted from '%s' to '%s' ... */ 3356 warning(259, arg, type_name(tn->tn_type), type_name(tp)); 3357 } 3358 } 3359 3360 /* 3361 * When converting a large integer type to a small integer type, in some 3362 * cases the value of the actual expression is further restricted than the 3363 * type bounds, such as in (expr & 0xFF) or (expr % 100) or (expr >> 24). 3364 */ 3365 static bool 3366 can_represent(const type_t *tp, const tnode_t *tn) 3367 { 3368 3369 debug_step("%s: type '%s'", __func__, type_name(tp)); 3370 debug_node(tn); 3371 3372 uint64_t nmask = value_bits(width_in_bits(tp)); 3373 if (!is_uinteger(tp->t_tspec)) 3374 nmask >>= 1; 3375 3376 integer_constraints c = ic_expr(tn); 3377 if ((~c.bclr & ~nmask) == 0) 3378 return true; 3379 3380 return false; 3381 } 3382 3383 static void 3384 convert_integer_from_integer(op_t op, int arg, tspec_t nt, tspec_t ot, 3385 type_t *tp, tnode_t *tn) 3386 { 3387 3388 if (tn->tn_op == CON) 3389 return; 3390 3391 if (op == CVT) 3392 return; 3393 3394 if (Pflag && pflag && aflag > 0 && 3395 portable_size_in_bits(nt) > portable_size_in_bits(ot) && 3396 is_uinteger(nt) != is_uinteger(ot)) { 3397 if (op == FARG) { 3398 /* conversion to '%s' may sign-extend ... */ 3399 warning(297, type_name(tp), arg); 3400 } else { 3401 /* conversion to '%s' may sign-extend ... */ 3402 warning(131, type_name(tp)); 3403 } 3404 } 3405 3406 if (Pflag && portable_size_in_bits(nt) > portable_size_in_bits(ot) && 3407 (tn->tn_op == PLUS || tn->tn_op == MINUS || tn->tn_op == MULT || 3408 tn->tn_op == SHL)) { 3409 /* suggest cast from '%s' to '%s' on op '%s' to ... */ 3410 warning(324, type_name(gettyp(ot)), type_name(tp), 3411 op_name(tn->tn_op)); 3412 } 3413 3414 if (aflag > 0 && 3415 portable_size_in_bits(nt) < portable_size_in_bits(ot) && 3416 (ot == LONG || ot == ULONG || ot == QUAD || ot == UQUAD || 3417 aflag > 1) && 3418 !can_represent(tp, tn)) { 3419 if (op == FARG) { 3420 /* conversion from '%s' to '%s' may lose ... */ 3421 warning(298, 3422 type_name(tn->tn_type), type_name(tp), arg); 3423 } else { 3424 /* conversion from '%s' to '%s' may lose accuracy */ 3425 warning(132, 3426 type_name(tn->tn_type), type_name(tp)); 3427 } 3428 } 3429 3430 if (is_uinteger(nt) != is_uinteger(ot)) 3431 /* implicit conversion changes sign from '%s' to '%s' */ 3432 query_message(3, type_name(tn->tn_type), type_name(tp)); 3433 } 3434 3435 static void 3436 convert_integer_from_pointer(op_t op, tspec_t nt, type_t *tp, tnode_t *tn) 3437 { 3438 3439 if (tn->tn_op == CON) 3440 return; 3441 if (op != CVT) 3442 return; /* We got already an error. */ 3443 if (portable_size_in_bits(nt) >= portable_size_in_bits(PTR)) 3444 return; 3445 3446 if (pflag && size_in_bits(nt) >= size_in_bits(PTR)) { 3447 /* conversion of pointer to '%s' may lose bits */ 3448 warning(134, type_name(tp)); 3449 } else { 3450 /* conversion of pointer to '%s' loses bits */ 3451 warning(133, type_name(tp)); 3452 } 3453 } 3454 3455 static bool 3456 struct_starts_with(const type_t *struct_tp, const type_t *member_tp) 3457 { 3458 3459 return struct_tp->t_str->sou_first_member != NULL && 3460 types_compatible(struct_tp->t_str->sou_first_member->s_type, 3461 member_tp, true, false, NULL); 3462 } 3463 3464 static bool 3465 is_byte_array(const type_t *tp) 3466 { 3467 3468 return tp->t_tspec == ARRAY && 3469 (tp->t_subt->t_tspec == CHAR || tp->t_subt->t_tspec == UCHAR); 3470 } 3471 3472 static bool 3473 should_warn_about_pointer_cast(const type_t *nstp, tspec_t nst, 3474 const type_t *ostp, tspec_t ost) 3475 { 3476 3477 while (nst == ARRAY) 3478 nstp = nstp->t_subt, nst = nstp->t_tspec; 3479 while (ost == ARRAY) 3480 ostp = ostp->t_subt, ost = ostp->t_tspec; 3481 3482 if (nst == STRUCT && ost == STRUCT && 3483 (struct_starts_with(nstp, ostp) || 3484 struct_starts_with(ostp, nstp))) 3485 return false; 3486 3487 if (is_incomplete(nstp) || is_incomplete(ostp)) 3488 return false; 3489 3490 if (nst == CHAR || nst == UCHAR) 3491 return false; /* for the sake of traditional C code */ 3492 if (ost == CHAR || ost == UCHAR) 3493 return false; /* for the sake of traditional C code */ 3494 3495 /* Allow cast between pointers to sockaddr variants. */ 3496 if (nst == STRUCT && ost == STRUCT) { 3497 debug_type(nstp); 3498 debug_type(ostp); 3499 const sym_t *nmem = nstp->t_str->sou_first_member; 3500 const sym_t *omem = ostp->t_str->sou_first_member; 3501 while (nmem != NULL && omem != NULL && 3502 types_compatible(nmem->s_type, omem->s_type, 3503 true, false, NULL)) 3504 nmem = nmem->s_next, omem = omem->s_next; 3505 if (nmem != NULL && is_byte_array(nmem->s_type)) 3506 return false; 3507 if (omem != NULL && is_byte_array(omem->s_type)) 3508 return false; 3509 if (nmem == NULL && omem == NULL) 3510 return false; 3511 } 3512 3513 if (is_struct_or_union(nst) && nstp->t_str != ostp->t_str) 3514 return true; 3515 3516 return portable_size_in_bits(nst) != portable_size_in_bits(ost); 3517 } 3518 3519 static void 3520 convert_pointer_from_pointer(type_t *ntp, tnode_t *tn) 3521 { 3522 const type_t *nstp, *otp, *ostp; 3523 tspec_t nst, ost; 3524 const char *nts, *ots; 3525 3526 nstp = ntp->t_subt; 3527 otp = tn->tn_type; 3528 ostp = otp->t_subt; 3529 nst = nstp->t_tspec; 3530 ost = ostp->t_tspec; 3531 3532 if (nst == VOID || ost == VOID) { 3533 /* TODO: C99 behaves like C90 here. */ 3534 if ((!allow_trad && !allow_c99) && (nst == FUNC || ost == FUNC)) { 3535 /* null pointers are already handled in convert() */ 3536 *(nst == FUNC ? &nts : &ots) = "function pointer"; 3537 *(nst == VOID ? &nts : &ots) = "'void *'"; 3538 /* ANSI C forbids conversion of %s to %s */ 3539 warning(303, ots, nts); 3540 } 3541 return; 3542 } else if (nst == FUNC && ost == FUNC) { 3543 return; 3544 } else if (nst == FUNC || ost == FUNC) { 3545 /* converting '%s' to '%s' is questionable */ 3546 warning(229, type_name(otp), type_name(ntp)); 3547 return; 3548 } 3549 3550 if (hflag && alignment_in_bits(nstp) > alignment_in_bits(ostp) && 3551 ost != CHAR && ost != UCHAR && 3552 !is_incomplete(ostp)) { 3553 /* converting '%s' to '%s' increases alignment ... */ 3554 warning(135, type_name(otp), type_name(ntp), 3555 alignment_in_bits(ostp) / CHAR_SIZE, 3556 alignment_in_bits(nstp) / CHAR_SIZE); 3557 } 3558 3559 if (cflag && should_warn_about_pointer_cast(nstp, nst, ostp, ost)) { 3560 /* pointer cast from '%s' to '%s' may be troublesome */ 3561 warning(247, type_name(otp), type_name(ntp)); 3562 } 3563 } 3564 3565 /* 3566 * Insert a conversion operator, which converts the type of the node 3567 * to another given type. 3568 * 3569 * Possible values for 'op': 3570 * CVT a cast-expression 3571 * binary integer promotion for one of the operands, or a usual 3572 * arithmetic conversion 3573 * binary plain or compound assignments to bit-fields 3574 * FARG 'arg' is the number of the argument (used for warnings) 3575 * NOOP several other implicit conversions 3576 * ... 3577 */ 3578 tnode_t * 3579 convert(op_t op, int arg, type_t *tp, tnode_t *tn) 3580 { 3581 tnode_t *ntn; 3582 tspec_t nt, ot; 3583 3584 nt = tp->t_tspec; 3585 ot = tn->tn_type->t_tspec; 3586 3587 if (allow_trad && allow_c90 && op == FARG) 3588 check_prototype_conversion(arg, nt, ot, tp, tn); 3589 3590 if (nt == BOOL) { 3591 /* No further checks. */ 3592 3593 } else if (is_integer(nt)) { 3594 if (ot == BOOL) { 3595 /* No further checks. */ 3596 } else if (is_integer(ot)) { 3597 convert_integer_from_integer(op, arg, nt, ot, tp, tn); 3598 } else if (is_floating(ot)) { 3599 convert_integer_from_floating(op, tp, tn); 3600 } else if (ot == PTR) { 3601 convert_integer_from_pointer(op, nt, tp, tn); 3602 } 3603 3604 } else if (is_floating(nt)) { 3605 /* No further checks. */ 3606 3607 } else if (nt == PTR) { 3608 if (is_null_pointer(tn)) { 3609 /* a null pointer may be assigned to any pointer. */ 3610 } else if (ot == PTR && op == CVT) { 3611 convert_pointer_from_pointer(tp, tn); 3612 } 3613 } 3614 3615 ntn = expr_alloc_tnode(); 3616 ntn->tn_op = CVT; 3617 ntn->tn_type = tp; 3618 ntn->tn_cast = op == CVT; 3619 ntn->tn_sys |= tn->tn_sys; 3620 ntn->tn_right = NULL; 3621 if (tn->tn_op != CON || nt == VOID) { 3622 ntn->tn_left = tn; 3623 } else { 3624 ntn->tn_op = CON; 3625 ntn->tn_val = expr_zero_alloc(sizeof(*ntn->tn_val)); 3626 convert_constant(op, arg, ntn->tn_type, ntn->tn_val, 3627 tn->tn_val); 3628 } 3629 3630 return ntn; 3631 } 3632 3633 static void 3634 convert_constant_floating(op_t op, int arg, tspec_t ot, const type_t *tp, 3635 tspec_t nt, val_t *v, val_t *nv) 3636 { 3637 ldbl_t max = 0.0, min = 0.0; 3638 3639 switch (nt) { 3640 case CHAR: 3641 max = TARG_CHAR_MAX; min = TARG_CHAR_MIN; break; 3642 case UCHAR: 3643 max = TARG_UCHAR_MAX; min = 0; break; 3644 case SCHAR: 3645 max = TARG_SCHAR_MAX; min = TARG_SCHAR_MIN; break; 3646 case SHORT: 3647 max = TARG_SHRT_MAX; min = TARG_SHRT_MIN; break; 3648 case USHORT: 3649 max = TARG_USHRT_MAX; min = 0; break; 3650 case ENUM: 3651 case INT: 3652 max = TARG_INT_MAX; min = TARG_INT_MIN; break; 3653 case UINT: 3654 max = TARG_UINT_MAX; min = 0; break; 3655 case LONG: 3656 max = TARG_LONG_MAX; min = TARG_LONG_MIN; break; 3657 case ULONG: 3658 max = TARG_ULONG_MAX; min = 0; break; 3659 case QUAD: 3660 max = QUAD_MAX; min = QUAD_MIN; break; 3661 case UQUAD: 3662 max = UQUAD_MAX; min = 0; break; 3663 case FLOAT: 3664 case FCOMPLEX: 3665 max = FLT_MAX; min = -FLT_MAX; break; 3666 case DOUBLE: 3667 case DCOMPLEX: 3668 max = DBL_MAX; min = -DBL_MAX; break; 3669 case PTR: 3670 /* Got already an error because of float --> ptr */ 3671 case LDOUBLE: 3672 case LCOMPLEX: 3673 /* LINTED 248 */ 3674 max = LDBL_MAX; min = -max; break; 3675 default: 3676 lint_assert(/*CONSTCOND*/false); 3677 } 3678 if (v->v_ldbl > max || v->v_ldbl < min) { 3679 lint_assert(nt != LDOUBLE); 3680 if (op == FARG) { 3681 /* conversion of '%s' to '%s' is out of range, ... */ 3682 warning(295, 3683 type_name(gettyp(ot)), type_name(tp), arg); 3684 } else { 3685 /* conversion of '%s' to '%s' is out of range */ 3686 warning(119, 3687 type_name(gettyp(ot)), type_name(tp)); 3688 } 3689 v->v_ldbl = v->v_ldbl > 0 ? max : min; 3690 } 3691 3692 if (nt == FLOAT) { 3693 nv->v_ldbl = (float)v->v_ldbl; 3694 } else if (nt == DOUBLE) { 3695 nv->v_ldbl = (double)v->v_ldbl; 3696 } else if (nt == LDOUBLE) { 3697 nv->v_ldbl = v->v_ldbl; 3698 } else { 3699 nv->v_quad = (int64_t)v->v_ldbl; 3700 } 3701 } 3702 3703 static bool 3704 convert_constant_to_floating(tspec_t nt, val_t *nv, 3705 tspec_t ot, const val_t *v) 3706 { 3707 if (nt == FLOAT) { 3708 nv->v_ldbl = (ot == PTR || is_uinteger(ot)) ? 3709 (float)(uint64_t)v->v_quad : (float)v->v_quad; 3710 } else if (nt == DOUBLE) { 3711 nv->v_ldbl = (ot == PTR || is_uinteger(ot)) ? 3712 (double)(uint64_t)v->v_quad : (double)v->v_quad; 3713 } else if (nt == LDOUBLE) { 3714 nv->v_ldbl = (ot == PTR || is_uinteger(ot)) ? 3715 (ldbl_t)(uint64_t)v->v_quad : (ldbl_t)v->v_quad; 3716 } else 3717 return false; 3718 return true; 3719 } 3720 3721 /* 3722 * Print a warning if bits which were set are lost due to the conversion. 3723 * This can happen with operator ORASS only. 3724 */ 3725 static void 3726 convert_constant_check_range_bitor(size_t nsz, size_t osz, const val_t *v, 3727 uint64_t xmask, op_t op) 3728 { 3729 if (nsz < osz && (v->v_quad & xmask) != 0) { 3730 /* constant truncated by conversion, op '%s' */ 3731 warning(306, op_name(op)); 3732 } 3733 } 3734 3735 /* 3736 * Print a warning if additional bits are not all 1 3737 * and the most significant bit of the old value is 1, 3738 * or if at least one (but not all) removed bit was 0. 3739 */ 3740 static void 3741 convert_constant_check_range_bitand(size_t nsz, size_t osz, 3742 uint64_t xmask, const val_t *nv, 3743 tspec_t ot, const val_t *v, 3744 const type_t *tp, op_t op) 3745 { 3746 if (nsz > osz && 3747 (nv->v_quad & bit((unsigned int)(osz - 1))) != 0 && 3748 (nv->v_quad & xmask) != xmask) { 3749 /* extra bits set to 0 in conversion of '%s' to '%s', ... */ 3750 warning(309, type_name(gettyp(ot)), 3751 type_name(tp), op_name(op)); 3752 } else if (nsz < osz && 3753 (v->v_quad & xmask) != xmask && 3754 (v->v_quad & xmask) != 0) { 3755 /* constant truncated by conversion, op '%s' */ 3756 warning(306, op_name(op)); 3757 } 3758 } 3759 3760 static void 3761 convert_constant_check_range_signed(op_t op, int arg) 3762 { 3763 if (op == ASSIGN) { 3764 /* assignment of negative constant to unsigned type */ 3765 warning(164); 3766 } else if (op == INIT) { 3767 /* initialization of unsigned with negative constant */ 3768 warning(221); 3769 } else if (op == FARG) { 3770 /* conversion of negative constant to unsigned type, ... */ 3771 warning(296, arg); 3772 } else if (modtab[op].m_comparison) { 3773 /* handled by check_integer_comparison() */ 3774 } else { 3775 /* conversion of negative constant to unsigned type */ 3776 warning(222); 3777 } 3778 } 3779 3780 /* 3781 * Loss of significant bit(s). All truncated bits 3782 * of unsigned types or all truncated bits plus the 3783 * msb of the target for signed types are considered 3784 * to be significant bits. Loss of significant bits 3785 * means that at least one of the bits was set in an 3786 * unsigned type or that at least one but not all of 3787 * the bits was set in a signed type. 3788 * Loss of significant bits means that it is not 3789 * possible, also not with necessary casts, to convert 3790 * back to the original type. A example for a 3791 * necessary cast is: 3792 * char c; int i; c = 128; 3793 * i = c; ** yields -128 ** 3794 * i = (unsigned char)c; ** yields 128 ** 3795 */ 3796 static void 3797 convert_constant_check_range_truncated(op_t op, int arg, const type_t *tp, 3798 tspec_t ot) 3799 { 3800 if (op == ASSIGN && tp->t_bitfield) { 3801 /* precision lost in bit-field assignment */ 3802 warning(166); 3803 } else if (op == ASSIGN) { 3804 /* constant truncated by assignment */ 3805 warning(165); 3806 } else if (op == INIT && tp->t_bitfield) { 3807 /* bit-field initializer does not fit */ 3808 warning(180); 3809 } else if (op == INIT) { 3810 /* initializer does not fit */ 3811 warning(178); 3812 } else if (op == CASE) { 3813 /* case label affected by conversion */ 3814 warning(196); 3815 } else if (op == FARG) { 3816 /* conversion of '%s' to '%s' is out of range, arg #%d */ 3817 warning(295, 3818 type_name(gettyp(ot)), type_name(tp), arg); 3819 } else { 3820 /* conversion of '%s' to '%s' is out of range */ 3821 warning(119, 3822 type_name(gettyp(ot)), type_name(tp)); 3823 } 3824 } 3825 3826 static void 3827 convert_constant_check_range_loss(op_t op, int arg, const type_t *tp, 3828 tspec_t ot) 3829 { 3830 if (op == ASSIGN && tp->t_bitfield) { 3831 /* precision lost in bit-field assignment */ 3832 warning(166); 3833 } else if (op == INIT && tp->t_bitfield) { 3834 /* bit-field initializer out of range */ 3835 warning(11); 3836 } else if (op == CASE) { 3837 /* case label affected by conversion */ 3838 warning(196); 3839 } else if (op == FARG) { 3840 /* conversion of '%s' to '%s' is out of range, arg #%d */ 3841 warning(295, 3842 type_name(gettyp(ot)), type_name(tp), arg); 3843 } else { 3844 /* conversion of '%s' to '%s' is out of range */ 3845 warning(119, 3846 type_name(gettyp(ot)), type_name(tp)); 3847 } 3848 } 3849 3850 static void 3851 convert_constant_check_range(tspec_t ot, const type_t *tp, tspec_t nt, 3852 op_t op, int arg, const val_t *v, val_t *nv) 3853 { 3854 unsigned int obitsz, nbitsz; 3855 uint64_t xmask, xmsk1; 3856 3857 obitsz = size_in_bits(ot); 3858 nbitsz = tp->t_bitfield ? tp->t_flen : size_in_bits(nt); 3859 xmask = value_bits(nbitsz) ^ value_bits(obitsz); 3860 xmsk1 = value_bits(nbitsz) ^ value_bits(obitsz - 1); 3861 /* 3862 * For bitwise operations we are not interested in the arithmetic 3863 * value, but in the bits itself. 3864 */ 3865 if (op == ORASS || op == BITOR || op == BITXOR) { 3866 convert_constant_check_range_bitor( 3867 nbitsz, obitsz, v, xmask, op); 3868 } else if (op == ANDASS || op == BITAND) { 3869 convert_constant_check_range_bitand( 3870 nbitsz, obitsz, xmask, nv, ot, v, tp, op); 3871 } else if ((nt != PTR && is_uinteger(nt)) && 3872 (ot != PTR && !is_uinteger(ot)) && 3873 v->v_quad < 0) { 3874 convert_constant_check_range_signed(op, arg); 3875 } else if (nv->v_quad != v->v_quad && nbitsz <= obitsz && 3876 (v->v_quad & xmask) != 0 && 3877 (is_uinteger(ot) || (v->v_quad & xmsk1) != xmsk1)) { 3878 convert_constant_check_range_truncated(op, arg, tp, ot); 3879 } else if (nv->v_quad != v->v_quad) { 3880 convert_constant_check_range_loss(op, arg, tp, ot); 3881 } 3882 } 3883 3884 /* 3885 * Converts a typed constant to a constant of another type. 3886 * 3887 * op operator which requires conversion 3888 * arg if op is FARG, # of argument 3889 * tp type in which to convert the constant 3890 * nv new constant 3891 * v old constant 3892 */ 3893 void 3894 convert_constant(op_t op, int arg, const type_t *tp, val_t *nv, val_t *v) 3895 { 3896 tspec_t ot, nt; 3897 unsigned int sz; 3898 bool range_check; 3899 3900 /* 3901 * TODO: make 'v' const; the name of this function does not suggest 3902 * that it modifies 'v'. 3903 */ 3904 ot = v->v_tspec; 3905 nt = nv->v_tspec = tp->t_tspec; 3906 range_check = false; 3907 3908 if (nt == BOOL) { /* C99 6.3.1.2 */ 3909 nv->v_unsigned_since_c90 = false; 3910 nv->v_quad = is_nonzero_val(v) ? 1 : 0; 3911 return; 3912 } 3913 3914 if (ot == FLOAT || ot == DOUBLE || ot == LDOUBLE) { 3915 convert_constant_floating(op, arg, ot, tp, nt, v, nv); 3916 } else if (!convert_constant_to_floating(nt, nv, ot, v)) { 3917 range_check = true; /* Check for lost precision. */ 3918 nv->v_quad = v->v_quad; 3919 } 3920 3921 if (allow_trad && allow_c90 && v->v_unsigned_since_c90 && 3922 (is_floating(nt) || ( 3923 (is_integer(nt) && !is_uinteger(nt) && 3924 portable_size_in_bits(nt) > portable_size_in_bits(ot))))) { 3925 /* ANSI C treats constant as unsigned */ 3926 warning(157); 3927 v->v_unsigned_since_c90 = false; 3928 } 3929 3930 if (is_integer(nt)) { 3931 sz = tp->t_bitfield ? tp->t_flen : size_in_bits(nt); 3932 nv->v_quad = convert_integer(nv->v_quad, nt, sz); 3933 } 3934 3935 if (range_check && op != CVT) 3936 convert_constant_check_range(ot, tp, nt, op, arg, v, nv); 3937 } 3938 3939 /* 3940 * Create a constant node for sizeof. 3941 */ 3942 tnode_t * 3943 build_sizeof(const type_t *tp) 3944 { 3945 unsigned int size_in_bytes = type_size_in_bits(tp) / CHAR_SIZE; 3946 tnode_t *tn = build_integer_constant(SIZEOF_TSPEC, size_in_bytes); 3947 tn->tn_system_dependent = true; 3948 debug_step("build_sizeof '%s' = %u", type_name(tp), size_in_bytes); 3949 return tn; 3950 } 3951 3952 /* 3953 * Create a constant node for offsetof. 3954 */ 3955 /* ARGSUSED */ /* FIXME: See implementation comments. */ 3956 tnode_t * 3957 build_offsetof(const type_t *tp, const sym_t *sym) 3958 { 3959 unsigned int offset_in_bytes; 3960 tnode_t *tn; 3961 3962 if (!is_struct_or_union(tp->t_tspec)) 3963 /* unacceptable operand of '%s' */ 3964 error(111, "offsetof"); 3965 3966 /* FIXME: Don't wrongly use the size of the whole type, use sym. */ 3967 offset_in_bytes = type_size_in_bits(tp) / CHAR_SIZE; 3968 tn = build_integer_constant(SIZEOF_TSPEC, offset_in_bytes); 3969 tn->tn_system_dependent = true; 3970 return tn; 3971 } 3972 3973 unsigned int 3974 type_size_in_bits(const type_t *tp) 3975 { 3976 unsigned int elem, elsz; 3977 bool flex; 3978 3979 elem = 1; 3980 flex = false; 3981 lint_assert(tp != NULL); 3982 while (tp->t_tspec == ARRAY) { 3983 flex = true; /* allow c99 flex arrays [] [0] */ 3984 elem *= tp->t_dim; 3985 tp = tp->t_subt; 3986 } 3987 if (elem == 0) { 3988 if (!flex) { 3989 /* cannot take size/alignment of incomplete type */ 3990 error(143); 3991 elem = 1; 3992 } 3993 } 3994 switch (tp->t_tspec) { 3995 case FUNC: 3996 /* cannot take size/alignment of function type '%s' */ 3997 error(144, type_name(tp)); 3998 elsz = 1; 3999 break; 4000 case STRUCT: 4001 case UNION: 4002 if (is_incomplete(tp)) { 4003 /* cannot take size/alignment of incomplete type */ 4004 error(143); 4005 elsz = 1; 4006 } else { 4007 elsz = tp->t_str->sou_size_in_bits; 4008 } 4009 break; 4010 case ENUM: 4011 if (is_incomplete(tp)) { 4012 /* cannot take size/alignment of incomplete type */ 4013 warning(143); 4014 } 4015 /* FALLTHROUGH */ 4016 default: 4017 if (tp->t_bitfield) { 4018 /* cannot take size/alignment of bit-field */ 4019 error(145); 4020 } 4021 if (tp->t_tspec == VOID) { 4022 /* cannot take size/alignment of void */ 4023 error(146); 4024 elsz = 1; 4025 } else { 4026 elsz = size_in_bits(tp->t_tspec); 4027 lint_assert(elsz > 0); 4028 } 4029 break; 4030 } 4031 4032 return elem * elsz; 4033 } 4034 4035 tnode_t * 4036 build_alignof(const type_t *tp) 4037 { 4038 switch (tp->t_tspec) { 4039 case ARRAY: 4040 break; 4041 4042 case FUNC: 4043 /* cannot take size/alignment of function type '%s' */ 4044 error(144, type_name(tp)); 4045 return 0; 4046 4047 case STRUCT: 4048 case UNION: 4049 if (is_incomplete(tp)) { 4050 /* cannot take size/alignment of incomplete type */ 4051 error(143); 4052 return 0; 4053 } 4054 break; 4055 case ENUM: 4056 break; 4057 default: 4058 if (tp->t_bitfield) { 4059 /* cannot take size/alignment of bit-field */ 4060 error(145); 4061 return 0; 4062 } 4063 if (tp->t_tspec == VOID) { 4064 /* cannot take size/alignment of void */ 4065 error(146); 4066 return 0; 4067 } 4068 break; 4069 } 4070 4071 return build_integer_constant(SIZEOF_TSPEC, 4072 (int64_t)alignment_in_bits(tp) / CHAR_SIZE); 4073 } 4074 4075 static tnode_t * 4076 cast_to_union(const tnode_t *otn, type_t *ntp) 4077 { 4078 4079 if (!allow_gcc) { 4080 /* union cast is a GCC extension */ 4081 error(328); 4082 return NULL; 4083 } 4084 4085 for (const sym_t *m = ntp->t_str->sou_first_member; 4086 m != NULL; m = m->s_next) { 4087 if (types_compatible(m->s_type, otn->tn_type, 4088 false, false, NULL)) { 4089 tnode_t *ntn = expr_alloc_tnode(); 4090 ntn->tn_op = CVT; 4091 ntn->tn_type = ntp; 4092 ntn->tn_cast = true; 4093 ntn->tn_right = NULL; 4094 return ntn; 4095 } 4096 } 4097 4098 /* type '%s' is not a member of '%s' */ 4099 error(329, type_name(otn->tn_type), type_name(ntp)); 4100 return NULL; 4101 } 4102 4103 /* 4104 * Type casts. 4105 */ 4106 tnode_t * 4107 cast(tnode_t *tn, type_t *tp) 4108 { 4109 tspec_t nt, ot; 4110 4111 if (tn == NULL) 4112 return NULL; 4113 4114 tn = cconv(tn); 4115 4116 lint_assert(tp != NULL); 4117 nt = tp->t_tspec; 4118 ot = tn->tn_type->t_tspec; 4119 4120 if (nt == VOID) { 4121 /* 4122 * C90 6.3.4, C99 6.5.4p2 and C11 6.5.4p2 allow any type to 4123 * be cast to void. The only other allowed casts are from a 4124 * scalar type to a scalar type. 4125 */ 4126 } else if (nt == UNION) { 4127 return cast_to_union(tn, tp); 4128 } else if (nt == STRUCT || nt == ARRAY || nt == FUNC) { 4129 /* Casting to a struct is an undocumented GCC extension. */ 4130 if (!(allow_gcc && nt == STRUCT)) 4131 goto invalid_cast; 4132 } else if (is_struct_or_union(ot)) { 4133 goto invalid_cast; 4134 } else if (ot == VOID) { 4135 /* improper cast of void expression */ 4136 error(148); 4137 return NULL; 4138 } else if (is_integer(nt) && is_scalar(ot)) { 4139 /* ok */ 4140 } else if (is_floating(nt) && is_arithmetic(ot)) { 4141 /* ok */ 4142 } else if (nt == PTR && is_integer(ot)) { 4143 /* ok */ 4144 } else if (nt == PTR && ot == PTR) { 4145 if (!tp->t_subt->t_const && tn->tn_type->t_subt->t_const) { 4146 if (hflag) 4147 /* cast discards 'const' from type '%s' */ 4148 warning(275, type_name(tn->tn_type)); 4149 } 4150 } else 4151 goto invalid_cast; 4152 4153 if (any_query_enabled && types_compatible(tp, tn->tn_type, 4154 false, false, NULL)) { 4155 /* no-op cast from '%s' to '%s' */ 4156 query_message(6, type_name(tn->tn_type), type_name(tp)); 4157 } 4158 4159 tn = convert(CVT, 0, tp, tn); 4160 tn->tn_cast = true; 4161 4162 return tn; 4163 4164 invalid_cast: 4165 /* invalid cast from '%s' to '%s' */ 4166 error(147, type_name(tn->tn_type), type_name(tp)); 4167 return NULL; 4168 } 4169 4170 /* 4171 * Create the node for a function argument. 4172 * All necessary conversions and type checks are done in 4173 * build_function_call because build_function_argument has no 4174 * information about expected argument types. 4175 */ 4176 tnode_t * 4177 build_function_argument(tnode_t *args, tnode_t *arg) 4178 { 4179 /* 4180 * If there was a serious error in the expression for the argument, 4181 * create a dummy argument so the positions of the remaining arguments 4182 * will not change. 4183 */ 4184 if (arg == NULL) 4185 arg = build_integer_constant(INT, 0); 4186 4187 return new_tnode(PUSH, arg->tn_sys, arg->tn_type, arg, args); 4188 } 4189 4190 /* 4191 * Compare the type of an argument with the corresponding type of a 4192 * prototype parameter. If it is a valid combination, but both types 4193 * are not the same, insert a conversion to convert the argument into 4194 * the type of the parameter. 4195 */ 4196 static tnode_t * 4197 check_prototype_argument( 4198 int n, /* pos of arg */ 4199 type_t *tp, /* expected type (from prototype) */ 4200 tnode_t *tn) /* argument */ 4201 { 4202 tnode_t *ln; 4203 bool dowarn; 4204 4205 ln = xcalloc(1, sizeof(*ln)); 4206 ln->tn_type = expr_unqualified_type(tp); 4207 ln->tn_lvalue = true; 4208 if (typeok(FARG, n, ln, tn)) { 4209 if (!types_compatible(tp, tn->tn_type, 4210 true, false, (dowarn = false, &dowarn)) || dowarn) 4211 tn = convert(FARG, n, tp, tn); 4212 } 4213 free(ln); 4214 return tn; 4215 } 4216 4217 /* 4218 * Check types of all function arguments and insert conversions, 4219 * if necessary. 4220 */ 4221 static tnode_t * 4222 check_function_arguments(type_t *ftp, tnode_t *args) 4223 { 4224 tnode_t *arg; 4225 sym_t *asym; 4226 tspec_t at; 4227 int narg, npar, n, i; 4228 4229 /* get # of args in the prototype */ 4230 npar = 0; 4231 for (asym = ftp->t_args; asym != NULL; asym = asym->s_next) 4232 npar++; 4233 4234 /* get # of args in function call */ 4235 narg = 0; 4236 for (arg = args; arg != NULL; arg = arg->tn_right) 4237 narg++; 4238 4239 asym = ftp->t_args; 4240 if (ftp->t_proto && npar != narg && !(ftp->t_vararg && npar < narg)) { 4241 /* argument mismatch: %d %s passed, %d expected */ 4242 error(150, narg, narg > 1 ? "arguments" : "argument", npar); 4243 asym = NULL; 4244 } 4245 4246 for (n = 1; n <= narg; n++) { 4247 4248 /* 4249 * The rightmost argument is at the top of the argument 4250 * subtree. 4251 */ 4252 for (i = narg, arg = args; i > n; i--, arg = arg->tn_right) 4253 continue; 4254 4255 /* some things which are always not allowed */ 4256 if ((at = arg->tn_left->tn_type->t_tspec) == VOID) { 4257 /* void expressions may not be arguments, arg #%d */ 4258 error(151, n); 4259 return NULL; 4260 } else if (is_struct_or_union(at) && 4261 is_incomplete(arg->tn_left->tn_type)) { 4262 /* argument cannot have unknown size, arg #%d */ 4263 error(152, n); 4264 return NULL; 4265 } else if (is_integer(at) && 4266 arg->tn_left->tn_type->t_is_enum && 4267 is_incomplete(arg->tn_left->tn_type)) { 4268 /* argument cannot have unknown size, arg #%d */ 4269 warning(152, n); 4270 } 4271 4272 /* class conversions (arg in value context) */ 4273 arg->tn_left = cconv(arg->tn_left); 4274 4275 if (asym != NULL) { 4276 arg->tn_left = check_prototype_argument( 4277 n, asym->s_type, arg->tn_left); 4278 } else { 4279 arg->tn_left = promote(NOOP, true, arg->tn_left); 4280 } 4281 arg->tn_type = arg->tn_left->tn_type; 4282 4283 if (asym != NULL) 4284 asym = asym->s_next; 4285 } 4286 4287 return args; 4288 } 4289 4290 /* 4291 * Create the node for a function call. Also check types of 4292 * function arguments and insert conversions, if necessary. 4293 */ 4294 tnode_t * 4295 build_function_call(tnode_t *func, bool sys, tnode_t *args) 4296 { 4297 tnode_t *ntn; 4298 op_t fcop; 4299 4300 if (func == NULL) 4301 return NULL; 4302 4303 if (func->tn_op == NAME && func->tn_type->t_tspec == FUNC) { 4304 fcop = CALL; 4305 } else { 4306 fcop = ICALL; 4307 } 4308 4309 check_ctype_function_call(func, args); 4310 4311 /* 4312 * after cconv() func will always be a pointer to a function 4313 * if it is a valid function designator. 4314 */ 4315 func = cconv(func); 4316 4317 if (func->tn_type->t_tspec != PTR || 4318 func->tn_type->t_subt->t_tspec != FUNC) { 4319 /* cannot call '%s', must be a function */ 4320 error(149, type_name(func->tn_type)); 4321 return NULL; 4322 } 4323 4324 args = check_function_arguments(func->tn_type->t_subt, args); 4325 4326 ntn = new_tnode(fcop, sys, func->tn_type->t_subt->t_subt, func, args); 4327 4328 return ntn; 4329 } 4330 4331 /* 4332 * Return the value of an integral constant expression. 4333 * If the expression is not constant or its type is not an integer 4334 * type, an error message is printed. 4335 */ 4336 val_t * 4337 constant(tnode_t *tn, bool required) 4338 { 4339 val_t *v; 4340 4341 if (tn != NULL) 4342 tn = cconv(tn); 4343 if (tn != NULL) 4344 tn = promote(NOOP, false, tn); 4345 4346 v = xcalloc(1, sizeof(*v)); 4347 4348 if (tn == NULL) { 4349 lint_assert(nerr != 0); 4350 debug_step("constant node is null; returning 1 instead"); 4351 v->v_tspec = INT; 4352 v->v_quad = 1; 4353 return v; 4354 } 4355 4356 v->v_tspec = tn->tn_type->t_tspec; 4357 4358 if (tn->tn_op == CON) { 4359 lint_assert(tn->tn_type->t_tspec == tn->tn_val->v_tspec); 4360 if (is_integer(tn->tn_val->v_tspec)) { 4361 v->v_unsigned_since_c90 = 4362 tn->tn_val->v_unsigned_since_c90; 4363 v->v_quad = tn->tn_val->v_quad; 4364 return v; 4365 } 4366 v->v_quad = tn->tn_val->v_ldbl; 4367 } else { 4368 v->v_quad = 1; 4369 } 4370 4371 if (required) 4372 /* integral constant expression expected */ 4373 error(55); 4374 else 4375 /* variable array dimension is a C99/GCC extension */ 4376 c99ism(318); 4377 4378 if (!is_integer(v->v_tspec)) 4379 v->v_tspec = INT; 4380 4381 return v; 4382 } 4383 4384 static bool 4385 is_constcond_false(const tnode_t *tn, tspec_t t) 4386 { 4387 return (t == BOOL || t == INT) && 4388 tn->tn_op == CON && tn->tn_val->v_quad == 0; 4389 } 4390 4391 /* 4392 * Perform some tests on expressions which can't be done in build_binary() 4393 * and functions called by build_binary(). These tests must be done here 4394 * because we need some information about the context in which the operations 4395 * are performed. 4396 * After all tests are performed and dofreeblk is true, expr() frees the 4397 * memory which is used for the expression. 4398 */ 4399 void 4400 expr(tnode_t *tn, bool vctx, bool cond, bool dofreeblk, bool is_do_while) 4401 { 4402 4403 if (tn == NULL) { /* in case of errors */ 4404 expr_free_all(); 4405 return; 4406 } 4407 4408 /* expr() is also called in global initializations */ 4409 if (dcs->d_kind != DK_EXTERN && !is_do_while) 4410 check_statement_reachable(); 4411 4412 check_expr_misc(tn, vctx, cond, !cond, false, false, false); 4413 if (tn->tn_op == ASSIGN) { 4414 if (hflag && cond) 4415 /* assignment in conditional context */ 4416 warning(159); 4417 } else if (tn->tn_op == CON) { 4418 if (hflag && cond && !constcond_flag && 4419 !tn->tn_system_dependent && 4420 !(is_do_while && 4421 is_constcond_false(tn, tn->tn_type->t_tspec))) 4422 /* constant in conditional context */ 4423 warning(161); 4424 } 4425 if (!modtab[tn->tn_op].m_has_side_effect) { 4426 /* 4427 * for left operands of COMMA this warning is already 4428 * printed 4429 */ 4430 if (tn->tn_op != COMMA && !vctx && !cond) 4431 check_null_effect(tn); 4432 } 4433 debug_node(tn); 4434 4435 /* free the tree memory */ 4436 if (dofreeblk) 4437 expr_free_all(); 4438 } 4439 4440 /* 4441 * Checks the range of array indices, if possible. 4442 * amper is set if only the address of the element is used. This 4443 * means that the index is allowed to refer to the first element 4444 * after the array. 4445 */ 4446 static void 4447 check_array_index(tnode_t *tn, bool amper) 4448 { 4449 int dim; 4450 tnode_t *ln, *rn; 4451 int elsz; 4452 int64_t con; 4453 4454 ln = tn->tn_left; 4455 rn = tn->tn_right; 4456 4457 /* We can only check constant indices. */ 4458 if (rn->tn_op != CON) 4459 return; 4460 4461 /* Return if the left node does not stem from an array. */ 4462 if (ln->tn_op != ADDR) 4463 return; 4464 if (ln->tn_left->tn_op != STRING && ln->tn_left->tn_op != NAME) 4465 return; 4466 if (ln->tn_left->tn_type->t_tspec != ARRAY) 4467 return; 4468 4469 /* 4470 * For incomplete array types, we can print a warning only if 4471 * the index is negative. 4472 */ 4473 if (is_incomplete(ln->tn_left->tn_type) && rn->tn_val->v_quad >= 0) 4474 return; 4475 4476 /* Get the size of one array element */ 4477 if ((elsz = length_in_bits(ln->tn_type->t_subt, NULL)) == 0) 4478 return; 4479 elsz /= CHAR_SIZE; 4480 4481 /* Change the unit of the index from bytes to element size. */ 4482 if (is_uinteger(rn->tn_type->t_tspec)) { 4483 con = (uint64_t)rn->tn_val->v_quad / elsz; 4484 } else { 4485 con = rn->tn_val->v_quad / elsz; 4486 } 4487 4488 dim = ln->tn_left->tn_type->t_dim + (amper ? 1 : 0); 4489 4490 if (!is_uinteger(rn->tn_type->t_tspec) && con < 0) { 4491 /* array subscript cannot be negative: %ld */ 4492 warning(167, (long)con); 4493 } else if (dim > 0 && (uint64_t)con >= (uint64_t)dim) { 4494 /* array subscript cannot be > %d: %ld */ 4495 warning(168, dim - 1, (long)con); 4496 } 4497 } 4498 4499 static void 4500 check_expr_addr(const tnode_t *ln, bool szof, bool fcall) 4501 { 4502 /* XXX: Taking warn_about_unreachable into account here feels wrong. */ 4503 if (ln->tn_op == NAME && (reached || !warn_about_unreachable)) { 4504 if (!szof) 4505 mark_as_set(ln->tn_sym); 4506 mark_as_used(ln->tn_sym, fcall, szof); 4507 } 4508 if (ln->tn_op == INDIR && ln->tn_left->tn_op == PLUS) 4509 /* check the range of array indices */ 4510 check_array_index(ln->tn_left, true); 4511 } 4512 4513 static void 4514 check_expr_load(const tnode_t *ln) 4515 { 4516 if (ln->tn_op == INDIR && ln->tn_left->tn_op == PLUS) 4517 /* check the range of array indices */ 4518 check_array_index(ln->tn_left, false); 4519 } 4520 4521 static void 4522 check_expr_side_effect(const tnode_t *ln, bool szof) 4523 { 4524 scl_t sc; 4525 dinfo_t *di; 4526 4527 /* XXX: Taking warn_about_unreachable into account here feels wrong. */ 4528 if (ln->tn_op == NAME && (reached || !warn_about_unreachable)) { 4529 sc = ln->tn_sym->s_scl; 4530 /* 4531 * Look if there was a asm statement in one of the 4532 * compound statements we are in. If not, we don't 4533 * print a warning. 4534 */ 4535 for (di = dcs; di != NULL; di = di->d_enclosing) { 4536 if (di->d_asm) 4537 break; 4538 } 4539 if (sc != EXTERN && sc != STATIC && 4540 !ln->tn_sym->s_set && !szof && di == NULL) { 4541 /* '%s' may be used before set */ 4542 warning(158, ln->tn_sym->s_name); 4543 mark_as_set(ln->tn_sym); 4544 } 4545 mark_as_used(ln->tn_sym, false, false); 4546 } 4547 } 4548 4549 static void 4550 check_expr_assign(const tnode_t *ln, bool szof) 4551 { 4552 /* XXX: Taking warn_about_unreachable into account here feels wrong. */ 4553 if (ln->tn_op == NAME && !szof && (reached || !warn_about_unreachable)) { 4554 mark_as_set(ln->tn_sym); 4555 if (ln->tn_sym->s_scl == EXTERN) 4556 outusg(ln->tn_sym); 4557 } 4558 if (ln->tn_op == INDIR && ln->tn_left->tn_op == PLUS) 4559 /* check the range of array indices */ 4560 check_array_index(ln->tn_left, false); 4561 } 4562 4563 static void 4564 check_expr_call(const tnode_t *tn, const tnode_t *ln, 4565 bool szof, bool vctx, bool cond, bool retval_discarded) 4566 { 4567 lint_assert(ln->tn_op == ADDR); 4568 lint_assert(ln->tn_left->tn_op == NAME); 4569 if (!szof && 4570 !is_compiler_builtin(ln->tn_left->tn_sym->s_name)) 4571 outcall(tn, vctx || cond, retval_discarded); 4572 } 4573 4574 static bool 4575 check_expr_op(const tnode_t *tn, op_t op, const tnode_t *ln, 4576 bool szof, bool fcall, bool vctx, bool cond, 4577 bool retval_discarded, bool eqwarn) 4578 { 4579 switch (op) { 4580 case ADDR: 4581 check_expr_addr(ln, szof, fcall); 4582 break; 4583 case LOAD: 4584 check_expr_load(ln); 4585 /* FALLTHROUGH */ 4586 case PUSH: 4587 case INCBEF: 4588 case DECBEF: 4589 case INCAFT: 4590 case DECAFT: 4591 case ADDASS: 4592 case SUBASS: 4593 case MULASS: 4594 case DIVASS: 4595 case MODASS: 4596 case ANDASS: 4597 case ORASS: 4598 case XORASS: 4599 case SHLASS: 4600 case SHRASS: 4601 case REAL: 4602 case IMAG: 4603 check_expr_side_effect(ln, szof); 4604 break; 4605 case ASSIGN: 4606 check_expr_assign(ln, szof); 4607 break; 4608 case CALL: 4609 check_expr_call(tn, ln, szof, vctx, cond, retval_discarded); 4610 break; 4611 case EQ: 4612 if (hflag && eqwarn) 4613 /* operator '==' found where '=' was expected */ 4614 warning(160); 4615 break; 4616 case CON: 4617 case NAME: 4618 case STRING: 4619 return false; 4620 default: 4621 break; 4622 } 4623 return true; 4624 } 4625 4626 /* 4627 * vctx ??? 4628 * cond whether the expression is a condition that 4629 * will be compared with 0 4630 * eqwarn whether the operator '==' might be a 4631 * misspelled '=' 4632 * fcall whether the expression is a function call 4633 * retval_discarded whether the return value of a function call 4634 * is discarded; such calls will be analyzed by 4635 * lint2 in messages 4, 8 and 9 4636 * szof whether the expression is part of a sizeof 4637 * expression, which means that its value is 4638 * discarded since only the type is relevant 4639 */ 4640 void 4641 check_expr_misc(const tnode_t *tn, bool vctx, bool cond, 4642 bool eqwarn, bool fcall, bool retval_discarded, bool szof) 4643 { 4644 tnode_t *ln, *rn; 4645 const mod_t *mp; 4646 op_t op; 4647 bool cvctx, ccond, eq, discard; 4648 4649 if (tn == NULL) 4650 return; 4651 4652 ln = tn->tn_left; 4653 rn = tn->tn_right; 4654 mp = &modtab[op = tn->tn_op]; 4655 4656 if (!check_expr_op(tn, op, ln, 4657 szof, fcall, vctx, cond, retval_discarded, eqwarn)) 4658 return; 4659 4660 cvctx = mp->m_value_context; 4661 ccond = mp->m_compares_with_zero; 4662 eq = mp->m_warn_if_operand_eq && 4663 !ln->tn_parenthesized && 4664 rn != NULL && !rn->tn_parenthesized; 4665 4666 /* 4667 * values of operands of ':' are not used if the type of at least 4668 * one of the operands (for gcc compatibility) is void 4669 * XXX test/value context of QUEST should probably be used as 4670 * context for both operands of COLON 4671 */ 4672 if (op == COLON && tn->tn_type->t_tspec == VOID) 4673 cvctx = ccond = false; 4674 discard = op == CVT && tn->tn_type->t_tspec == VOID; 4675 check_expr_misc(ln, cvctx, ccond, eq, op == CALL, discard, szof); 4676 4677 switch (op) { 4678 case PUSH: 4679 if (rn != NULL) 4680 check_expr_misc(rn, false, false, eq, false, false, 4681 szof); 4682 break; 4683 case LOGAND: 4684 case LOGOR: 4685 check_expr_misc(rn, false, true, eq, false, false, szof); 4686 break; 4687 case COLON: 4688 check_expr_misc(rn, cvctx, ccond, eq, false, false, szof); 4689 break; 4690 case COMMA: 4691 check_expr_misc(rn, vctx, cond, false, false, false, szof); 4692 break; 4693 default: 4694 if (mp->m_binary) 4695 check_expr_misc(rn, true, false, eq, false, false, 4696 szof); 4697 break; 4698 } 4699 } 4700 4701 /* 4702 * Return whether the expression can be used for static initialization. 4703 * 4704 * Constant initialization expressions must be constant or an address 4705 * of a static object with an optional offset. In the first case, 4706 * the result is returned in *offsp. In the second case, the static 4707 * object is returned in *symp and the offset in *offsp. 4708 * 4709 * The expression can consist of PLUS, MINUS, ADDR, NAME, STRING and 4710 * CON. Type conversions are allowed if they do not change binary 4711 * representation (including width). 4712 * 4713 * C99 6.6 "Constant expressions" 4714 * C99 6.7.8p4 restricts initializers for static storage duration 4715 */ 4716 bool 4717 constant_addr(const tnode_t *tn, const sym_t **symp, ptrdiff_t *offsp) 4718 { 4719 const sym_t *sym; 4720 ptrdiff_t offs1, offs2; 4721 tspec_t t, ot; 4722 4723 switch (tn->tn_op) { 4724 case MINUS: 4725 if (tn->tn_right->tn_op == CVT) 4726 return constant_addr(tn->tn_right, symp, offsp); 4727 else if (tn->tn_right->tn_op != CON) 4728 return false; 4729 /* FALLTHROUGH */ 4730 case PLUS: 4731 offs1 = offs2 = 0; 4732 if (tn->tn_left->tn_op == CON) { 4733 offs1 = (ptrdiff_t)tn->tn_left->tn_val->v_quad; 4734 if (!constant_addr(tn->tn_right, &sym, &offs2)) 4735 return false; 4736 } else if (tn->tn_right->tn_op == CON) { 4737 offs2 = (ptrdiff_t)tn->tn_right->tn_val->v_quad; 4738 if (tn->tn_op == MINUS) 4739 offs2 = -offs2; 4740 if (!constant_addr(tn->tn_left, &sym, &offs1)) 4741 return false; 4742 } else { 4743 return false; 4744 } 4745 *symp = sym; 4746 *offsp = offs1 + offs2; 4747 return true; 4748 case ADDR: 4749 if (tn->tn_left->tn_op == NAME) { 4750 *symp = tn->tn_left->tn_sym; 4751 *offsp = 0; 4752 return true; 4753 } else { 4754 /* 4755 * If this would be the front end of a compiler we 4756 * would return a label instead of 0, at least if 4757 * 'tn->tn_left->tn_op == STRING'. 4758 */ 4759 *symp = NULL; 4760 *offsp = 0; 4761 return true; 4762 } 4763 case CVT: 4764 t = tn->tn_type->t_tspec; 4765 ot = tn->tn_left->tn_type->t_tspec; 4766 if ((!is_integer(t) && t != PTR) || 4767 (!is_integer(ot) && ot != PTR)) { 4768 return false; 4769 } 4770 #if 0 4771 /* 4772 * consider: 4773 * struct foo { 4774 * unsigned char a; 4775 * } f = { 4776 * (unsigned char)(unsigned long) 4777 * (&(((struct foo *)0)->a)) 4778 * }; 4779 * since psize(unsigned long) != psize(unsigned char), 4780 * this fails. 4781 */ 4782 else if (psize(t) != psize(ot)) 4783 return -1; 4784 #endif 4785 return constant_addr(tn->tn_left, symp, offsp); 4786 default: 4787 return false; 4788 } 4789 } 4790 4791 /* Append s2 to s1, then free s2. */ 4792 strg_t * 4793 cat_strings(strg_t *s1, strg_t *s2) 4794 { 4795 4796 if (s1->st_char != s2->st_char) { 4797 /* cannot concatenate wide and regular string literals */ 4798 error(292); 4799 return s1; 4800 } 4801 4802 size_t len1 = s1->st_len; 4803 size_t len2 = s2->st_len; 4804 size_t chsize = s1->st_char ? sizeof(char) : sizeof(wchar_t); 4805 size_t size1 = len1 * chsize; 4806 size_t size2 = (len2 + 1) * chsize; 4807 s1->st_mem = xrealloc(s1->st_mem, size1 + size2); 4808 memcpy((char *)s1->st_mem + size1, s2->st_mem, size2); 4809 free(s2->st_mem); 4810 4811 s1->st_len = len1 + len2; 4812 free(s2); 4813 4814 return s1; 4815 } 4816 4817 4818 typedef struct stmt_expr { 4819 memory_pool se_mem; 4820 sym_t *se_sym; 4821 struct stmt_expr *se_enclosing; 4822 } stmt_expr; 4823 4824 static stmt_expr *stmt_exprs; 4825 4826 void 4827 begin_statement_expr(void) 4828 { 4829 stmt_expr *se = xmalloc(sizeof(*se)); 4830 se->se_mem = expr_save_memory(); 4831 se->se_sym = NULL; 4832 se->se_enclosing = stmt_exprs; 4833 stmt_exprs = se; 4834 } 4835 4836 void 4837 do_statement_expr(tnode_t *tn) 4838 { 4839 block_level--; 4840 mem_block_level--; 4841 stmt_exprs->se_sym = tn != NULL 4842 ? mktempsym(block_dup_type(tn->tn_type)) 4843 : NULL; /* after a syntax error */ 4844 mem_block_level++; 4845 block_level++; 4846 /* ({ }) is a GCC extension */ 4847 gnuism(320); 4848 } 4849 4850 tnode_t * 4851 end_statement_expr(void) 4852 { 4853 stmt_expr *se = stmt_exprs; 4854 if (se->se_sym == NULL) 4855 return NULL; /* after a syntax error */ 4856 tnode_t *tn = build_name(se->se_sym, false); 4857 (void)expr_save_memory(); /* leak */ 4858 expr_restore_memory(se->se_mem); 4859 stmt_exprs = se->se_enclosing; 4860 free(se); 4861 return tn; 4862 } 4863
Indexes created Fri Oct 03 17:10:05 GMT 2025