tree.c revision 1.520
1 /* $NetBSD: tree.c,v 1.520 2023/05/09 15:45:06 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 1.520 2023/05/09 15:45:06 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 unsigned nw = width_in_bits(ntp); 151 unsigned ow = width_in_bits(otp); 152 bool nu = is_uinteger(ntp->t_tspec); 153 bool ou = is_uinteger(otp->t_tspec); 154 155 if (nw >= ow && nu == ou) 156 return a; 157 if (nw > ow && ou) 158 return a; 159 return ic_any(ntp); 160 } 161 162 static integer_constraints 163 ic_bitand(integer_constraints a, integer_constraints b) 164 { 165 integer_constraints c; 166 167 c.smin = INT64_MIN; 168 c.smax = INT64_MAX; 169 c.umin = 0; 170 c.umax = UINT64_MAX; 171 c.bset = a.bset & b.bset; 172 c.bclr = a.bclr | b.bclr; 173 return c; 174 } 175 176 static integer_constraints 177 ic_bitor(integer_constraints a, integer_constraints b) 178 { 179 integer_constraints c; 180 181 c.smin = INT64_MIN; 182 c.smax = INT64_MAX; 183 c.umin = 0; 184 c.umax = UINT64_MAX; 185 c.bset = a.bset | b.bset; 186 c.bclr = a.bclr & b.bclr; 187 return c; 188 } 189 190 static integer_constraints 191 ic_mod(const type_t *tp, integer_constraints a, integer_constraints b) 192 { 193 integer_constraints c; 194 195 if (ic_maybe_signed(tp, &a) || ic_maybe_signed(tp, &b)) 196 return ic_any(tp); 197 198 c.smin = INT64_MIN; 199 c.smax = INT64_MAX; 200 c.umin = 0; 201 c.umax = b.umax - 1; 202 c.bset = 0; 203 c.bclr = ~u64_fill_right(c.umax); 204 return c; 205 } 206 207 static integer_constraints 208 ic_shl(const type_t *tp, integer_constraints a, integer_constraints b) 209 { 210 integer_constraints c; 211 unsigned int amount; 212 213 if (ic_maybe_signed(tp, &a)) 214 return ic_any(tp); 215 216 if (b.smin == b.smax && b.smin >= 0 && b.smin < 64) 217 amount = (unsigned int)b.smin; 218 else if (b.umin == b.umax && b.umin < 64) 219 amount = (unsigned int)b.umin; 220 else 221 return ic_any(tp); 222 223 c.smin = INT64_MIN; 224 c.smax = INT64_MAX; 225 c.umin = 0; 226 c.umax = UINT64_MAX; 227 c.bset = a.bset << amount; 228 c.bclr = a.bclr << amount | (((uint64_t)1 << amount) - 1); 229 return c; 230 } 231 232 static integer_constraints 233 ic_shr(const type_t *tp, integer_constraints a, integer_constraints b) 234 { 235 integer_constraints c; 236 unsigned int amount; 237 238 if (ic_maybe_signed(tp, &a)) 239 return ic_any(tp); 240 241 if (b.smin == b.smax && b.smin >= 0 && b.smin < 64) 242 amount = (unsigned int)b.smin; 243 else if (b.umin == b.umax && b.umin < 64) 244 amount = (unsigned int)b.umin; 245 else 246 return ic_any(tp); 247 248 c.smin = INT64_MIN; 249 c.smax = INT64_MAX; 250 c.umin = 0; 251 c.umax = UINT64_MAX; 252 c.bset = a.bset >> amount; 253 c.bclr = a.bclr >> amount | ~(~(uint64_t)0 >> amount); 254 return c; 255 } 256 257 static integer_constraints 258 ic_expr(const tnode_t *tn) 259 { 260 integer_constraints lc, rc; 261 262 lint_assert(is_integer(tn->tn_type->t_tspec)); 263 264 switch (tn->tn_op) { 265 case CON: 266 return ic_con(tn->tn_type, tn->tn_val); 267 case CVT: 268 if (!is_integer(tn->tn_left->tn_type->t_tspec)) 269 return ic_any(tn->tn_type); 270 lc = ic_expr(tn->tn_left); 271 return ic_cvt(tn->tn_type, tn->tn_left->tn_type, lc); 272 case MOD: 273 lc = ic_expr(before_conversion(tn->tn_left)); 274 rc = ic_expr(before_conversion(tn->tn_right)); 275 return ic_mod(tn->tn_type, lc, rc); 276 case SHL: 277 lc = ic_expr(tn->tn_left); 278 rc = ic_expr(tn->tn_right); 279 return ic_shl(tn->tn_type, lc, rc); 280 case SHR: 281 lc = ic_expr(tn->tn_left); 282 rc = ic_expr(tn->tn_right); 283 return ic_shr(tn->tn_type, lc, rc); 284 case BITAND: 285 lc = ic_expr(tn->tn_left); 286 rc = ic_expr(tn->tn_right); 287 return ic_bitand(lc, rc); 288 case BITOR: 289 lc = ic_expr(tn->tn_left); 290 rc = ic_expr(tn->tn_right); 291 return ic_bitor(lc, rc); 292 default: 293 return ic_any(tn->tn_type); 294 } 295 } 296 297 /* Build 'pointer to tp', 'array of tp' or 'function returning tp'. */ 298 type_t * 299 block_derive_type(type_t *tp, tspec_t t) 300 { 301 type_t *tp2; 302 303 tp2 = block_zero_alloc(sizeof(*tp2)); 304 tp2->t_tspec = t; 305 tp2->t_subt = tp; 306 return tp2; 307 } 308 309 /* 310 * Derive 'pointer to tp' or 'function returning tp'. 311 * The memory is freed at the end of the current expression. 312 */ 313 type_t * 314 expr_derive_type(type_t *tp, tspec_t t) 315 { 316 type_t *tp2; 317 318 tp2 = expr_zero_alloc(sizeof(*tp2)); 319 tp2->t_tspec = t; 320 tp2->t_subt = tp; 321 return tp2; 322 } 323 324 /* 325 * Build and initialize a new node. 326 */ 327 static tnode_t * 328 new_tnode(op_t op, bool sys, type_t *type, tnode_t *ln, tnode_t *rn) 329 { 330 331 tnode_t *ntn = expr_alloc_tnode(); 332 ntn->tn_op = op; 333 ntn->tn_type = type; 334 ntn->tn_sys = sys; 335 ntn->tn_left = ln; 336 ntn->tn_right = rn; 337 338 if (op == INDIR || op == FSEL) { 339 lint_assert(ln->tn_type->t_tspec == PTR); 340 tspec_t t = ln->tn_type->t_subt->t_tspec; 341 if (t != FUNC && t != VOID) 342 ntn->tn_lvalue = true; 343 } 344 345 return ntn; 346 } 347 348 /* 349 * Create a node for a constant. 350 */ 351 tnode_t * 352 build_constant(type_t *tp, val_t *v) 353 { 354 tnode_t *n; 355 356 n = expr_alloc_tnode(); 357 n->tn_op = CON; 358 n->tn_type = tp; 359 n->tn_val = expr_zero_alloc(sizeof(*n->tn_val)); 360 n->tn_val->v_tspec = tp->t_tspec; 361 n->tn_val->v_unsigned_since_c90 = v->v_unsigned_since_c90; 362 n->tn_val->v_u = v->v_u; 363 free(v); 364 return n; 365 } 366 367 static tnode_t * 368 build_integer_constant(tspec_t t, int64_t q) 369 { 370 tnode_t *n; 371 372 n = expr_alloc_tnode(); 373 n->tn_op = CON; 374 n->tn_type = gettyp(t); 375 n->tn_val = expr_zero_alloc(sizeof(*n->tn_val)); 376 n->tn_val->v_tspec = t; 377 n->tn_val->v_quad = q; 378 return n; 379 } 380 381 static void 382 fallback_symbol(sym_t *sym) 383 { 384 385 if (Tflag && fallback_symbol_strict_bool(sym)) 386 return; 387 388 if (block_level > 0 && (strcmp(sym->s_name, "__FUNCTION__") == 0 || 389 strcmp(sym->s_name, "__PRETTY_FUNCTION__") == 0)) { 390 /* __FUNCTION__/__PRETTY_FUNCTION__ is a GCC extension */ 391 gnuism(316); 392 sym->s_type = block_derive_type(gettyp(CHAR), PTR); 393 sym->s_type->t_const = true; 394 return; 395 } 396 397 if (block_level > 0 && strcmp(sym->s_name, "__func__") == 0) { 398 if (!allow_c99) 399 /* __func__ is a C99 feature */ 400 warning(317); 401 /* C11 6.4.2.2 */ 402 sym->s_type = block_derive_type(gettyp(CHAR), ARRAY); 403 sym->s_type->t_const = true; 404 sym->s_type->t_dim = (int)strlen(funcsym->s_name) + 1; 405 return; 406 } 407 408 /* '%s' undefined */ 409 error(99, sym->s_name); 410 } 411 412 /* 413 * Functions that are predeclared by GCC or other compilers can be called 414 * with arbitrary arguments. Since lint usually runs after a successful 415 * compilation, it's the compiler's job to catch any errors. 416 */ 417 bool 418 is_compiler_builtin(const char *name) 419 { 420 /* https://gcc.gnu.org/onlinedocs/gcc/C-Extensions.html */ 421 if (allow_gcc) { 422 if (strncmp(name, "__atomic_", 9) == 0 || 423 strncmp(name, "__builtin_", 10) == 0 || 424 strcmp(name, "alloca") == 0 || 425 /* obsolete but still in use, as of 2021 */ 426 strncmp(name, "__sync_", 7) == 0) 427 return true; 428 } 429 430 /* https://software.intel.com/sites/landingpage/IntrinsicsGuide/ */ 431 if (strncmp(name, "_mm_", 4) == 0) 432 return true; 433 434 return false; 435 } 436 437 /* https://gcc.gnu.org/onlinedocs/gcc/Integer-Overflow-Builtins.html */ 438 static bool 439 is_gcc_bool_builtin(const char *name) 440 { 441 return strncmp(name, "__builtin_", 10) == 0 && 442 (str_endswith(name, "_overflow") || 443 str_endswith(name, "_overflow_p")); 444 } 445 446 static void 447 build_name_call(sym_t *sym) 448 { 449 450 if (is_compiler_builtin(sym->s_name)) { 451 /* 452 * Do not warn about these, just assume that 453 * they are regular functions compatible with 454 * non-prototype calling conventions. 455 */ 456 if (allow_gcc && is_gcc_bool_builtin(sym->s_name)) 457 sym->s_type = gettyp(BOOL); 458 459 } else if (allow_c99) { 460 /* function '%s' implicitly declared to return int */ 461 error(215, sym->s_name); 462 } else if (!allow_trad) { 463 /* function '%s' implicitly declared to return int */ 464 warning(215, sym->s_name); 465 } 466 467 /* XXX if !allow_c90, the symbol should be exported to level 0 */ 468 sym->s_type = block_derive_type(sym->s_type, FUNC); 469 } 470 471 /* Create a node for a name (symbol table entry). */ 472 tnode_t * 473 build_name(sym_t *sym, bool is_funcname) 474 { 475 tnode_t *n; 476 477 if (sym->s_scl == NOSCL && !in_gcc_attribute) { 478 sym->s_scl = EXTERN; 479 sym->s_def = DECL; 480 if (is_funcname) 481 build_name_call(sym); 482 else 483 fallback_symbol(sym); 484 } 485 486 lint_assert(sym->s_kind == FVFT || sym->s_kind == FMEMBER); 487 488 n = expr_alloc_tnode(); 489 n->tn_type = sym->s_type; 490 if (sym->s_scl == BOOL_CONST) { 491 n->tn_op = CON; 492 n->tn_val = expr_zero_alloc(sizeof(*n->tn_val)); 493 n->tn_val->v_tspec = BOOL; 494 n->tn_val->v_quad = sym->u.s_bool_constant ? 1 : 0; 495 } else if (sym->s_scl == ENUM_CONST) { 496 n->tn_op = CON; 497 n->tn_val = expr_zero_alloc(sizeof(*n->tn_val)); 498 n->tn_val->v_tspec = INT; /* ENUM is in n->tn_type */ 499 n->tn_val->v_quad = sym->u.s_enum_constant; 500 } else { 501 n->tn_op = NAME; 502 n->tn_sym = sym; 503 if (sym->s_kind == FVFT && sym->s_type->t_tspec != FUNC) 504 n->tn_lvalue = true; 505 } 506 507 return n; 508 } 509 510 tnode_t * 511 build_string(strg_t *strg) 512 { 513 size_t len; 514 tnode_t *n; 515 type_t *tp; 516 517 len = strg->st_len; 518 519 n = expr_alloc_tnode(); 520 521 tp = expr_zero_alloc(sizeof(*tp)); 522 tp->t_tspec = ARRAY; 523 tp->t_subt = gettyp(strg->st_char ? CHAR : WCHAR); 524 tp->t_dim = (int)(len + 1); 525 526 n->tn_op = STRING; 527 n->tn_type = tp; 528 n->tn_lvalue = true; 529 530 n->tn_string = expr_zero_alloc(sizeof(*n->tn_string)); 531 n->tn_string->st_char = strg->st_char; 532 n->tn_string->st_len = len; 533 534 size_t chsize = strg->st_char ? sizeof(char) : sizeof(wchar_t); 535 size_t size = (len + 1) * chsize; 536 n->tn_string->st_mem = expr_zero_alloc(size); 537 (void)memcpy(n->tn_string->st_mem, strg->st_mem, size); 538 free(strg->st_mem); 539 free(strg); 540 541 return n; 542 } 543 544 tnode_t * 545 build_generic_selection(const tnode_t *expr, 546 struct generic_association *sel) 547 { 548 tnode_t *default_result = NULL; 549 550 for (; sel != NULL; sel = sel->ga_prev) { 551 if (expr != NULL && 552 types_compatible(sel->ga_arg, expr->tn_type, 553 false, false, NULL)) 554 return sel->ga_result; 555 else if (sel->ga_arg == NULL) 556 default_result = sel->ga_result; 557 } 558 return default_result; 559 } 560 561 static bool 562 is_out_of_char_range(const tnode_t *tn) 563 { 564 return tn->tn_op == CON && 565 !(0 <= tn->tn_val->v_quad && 566 tn->tn_val->v_quad < 1 << (CHAR_SIZE - 1)); 567 } 568 569 /* 570 * Check for ordered comparisons of unsigned values with 0. 571 */ 572 static void 573 check_integer_comparison(op_t op, tnode_t *ln, tnode_t *rn) 574 { 575 tspec_t lt, rt; 576 577 lt = ln->tn_type->t_tspec; 578 rt = rn->tn_type->t_tspec; 579 580 if (ln->tn_op != CON && rn->tn_op != CON) 581 return; 582 583 if (!is_integer(lt) || !is_integer(rt)) 584 return; 585 586 if (hflag || pflag) { 587 if (lt == CHAR && is_out_of_char_range(rn)) { 588 char buf[128]; 589 (void)snprintf(buf, sizeof(buf), "%s %d", 590 op_name(op), (int)rn->tn_val->v_quad); 591 /* nonportable character comparison '%s' */ 592 warning(230, buf); 593 return; 594 } 595 if (rt == CHAR && is_out_of_char_range(ln)) { 596 char buf[128]; 597 (void)snprintf(buf, sizeof(buf), "%d %s ?", 598 (int)ln->tn_val->v_quad, op_name(op)); 599 /* nonportable character comparison '%s' */ 600 warning(230, buf); 601 return; 602 } 603 } 604 605 if (is_uinteger(lt) && !is_uinteger(rt) && 606 rn->tn_op == CON && rn->tn_val->v_quad <= 0) { 607 if (rn->tn_val->v_quad < 0) { 608 /* operator '%s' compares '%s' with '%s' */ 609 warning(162, op_name(op), 610 type_name(ln->tn_type), "negative constant"); 611 } else if (op == LT || op == GE) { 612 /* operator '%s' compares '%s' with '%s' */ 613 warning(162, op_name(op), type_name(ln->tn_type), "0"); 614 } 615 return; 616 } 617 if (is_uinteger(rt) && !is_uinteger(lt) && 618 ln->tn_op == CON && ln->tn_val->v_quad <= 0) { 619 if (ln->tn_val->v_quad < 0) { 620 /* operator '%s' compares '%s' with '%s' */ 621 warning(162, op_name(op), 622 "negative constant", type_name(rn->tn_type)); 623 } else if (op == GT || op == LE) { 624 /* operator '%s' compares '%s' with '%s' */ 625 warning(162, op_name(op), "0", type_name(rn->tn_type)); 626 } 627 return; 628 } 629 } 630 631 static const tspec_t arith_rank[] = { 632 LDOUBLE, DOUBLE, FLOAT, 633 #ifdef INT128_SIZE 634 UINT128, INT128, 635 #endif 636 UQUAD, QUAD, 637 ULONG, LONG, 638 UINT, INT, 639 }; 640 641 /* Keep unsigned in traditional C */ 642 static tspec_t 643 usual_arithmetic_conversion_trad(tspec_t lt, tspec_t rt) 644 { 645 646 size_t i; 647 for (i = 0; arith_rank[i] != INT; i++) 648 if (lt == arith_rank[i] || rt == arith_rank[i]) 649 break; 650 651 tspec_t t = arith_rank[i]; 652 if (is_uinteger(lt) || is_uinteger(rt)) 653 if (is_integer(t) && !is_uinteger(t)) 654 return unsigned_type(t); 655 return t; 656 } 657 658 static tspec_t 659 usual_arithmetic_conversion_c90(tspec_t lt, tspec_t rt) 660 { 661 662 if (lt == rt) 663 return lt; 664 665 if (lt == LCOMPLEX || rt == LCOMPLEX) 666 return LCOMPLEX; 667 if (lt == DCOMPLEX || rt == DCOMPLEX) 668 return DCOMPLEX; 669 if (lt == FCOMPLEX || rt == FCOMPLEX) 670 return FCOMPLEX; 671 if (lt == LDOUBLE || rt == LDOUBLE) 672 return LDOUBLE; 673 if (lt == DOUBLE || rt == DOUBLE) 674 return DOUBLE; 675 if (lt == FLOAT || rt == FLOAT) 676 return FLOAT; 677 678 /* 679 * If type A has more bits than type B, it should be able to hold all 680 * possible values of type B. 681 */ 682 if (size_in_bits(lt) > size_in_bits(rt)) 683 return lt; 684 if (size_in_bits(lt) < size_in_bits(rt)) 685 return rt; 686 687 size_t i; 688 for (i = 3; arith_rank[i] != INT; i++) 689 if (arith_rank[i] == lt || arith_rank[i] == rt) 690 break; 691 if ((is_uinteger(lt) || is_uinteger(rt)) && 692 !is_uinteger(arith_rank[i])) 693 i--; 694 return arith_rank[i]; 695 } 696 697 static tnode_t * 698 apply_usual_arithmetic_conversions(op_t op, tnode_t *tn, tspec_t t) 699 { 700 type_t *ntp = expr_dup_type(tn->tn_type); 701 ntp->t_tspec = t; 702 if (tn->tn_op != CON) { 703 /* usual arithmetic conversion for '%s' from '%s' to '%s' */ 704 query_message(4, op_name(op), 705 type_name(tn->tn_type), type_name(ntp)); 706 } 707 return convert(op, 0, ntp, tn); 708 } 709 710 /* 711 * Apply the "usual arithmetic conversions" (C99 6.3.1.8), which gives both 712 * operands the same type. 713 */ 714 static void 715 balance(op_t op, tnode_t **lnp, tnode_t **rnp) 716 { 717 718 tspec_t lt = (*lnp)->tn_type->t_tspec; 719 tspec_t rt = (*rnp)->tn_type->t_tspec; 720 if (!is_arithmetic(lt) || !is_arithmetic(rt)) 721 return; 722 723 tspec_t t = allow_c90 724 ? usual_arithmetic_conversion_c90(lt, rt) 725 : usual_arithmetic_conversion_trad(lt, rt); 726 727 if (t != lt) 728 *lnp = apply_usual_arithmetic_conversions(op, *lnp, t); 729 if (t != rt) 730 *rnp = apply_usual_arithmetic_conversions(op, *rnp, t); 731 } 732 733 /* 734 * Create a tree node for the unary & operator 735 */ 736 static tnode_t * 737 build_address(bool sys, tnode_t *tn, bool noign) 738 { 739 tspec_t t; 740 741 if (!noign && ((t = tn->tn_type->t_tspec) == ARRAY || t == FUNC)) { 742 if (!allow_c90) 743 /* '&' before array or function: ignored */ 744 warning(127); 745 return tn; 746 } 747 748 /* eliminate &* */ 749 if (tn->tn_op == INDIR && 750 tn->tn_left->tn_type->t_tspec == PTR && 751 tn->tn_left->tn_type->t_subt == tn->tn_type) { 752 return tn->tn_left; 753 } 754 755 return new_tnode(ADDR, sys, expr_derive_type(tn->tn_type, PTR), 756 tn, NULL); 757 } 758 759 /* 760 * XXX 761 * Note: There appear to be a number of bugs in detecting overflow in 762 * this function. An audit and a set of proper regression tests are needed. 763 * --Perry Metzger, Nov. 16, 2001 764 */ 765 /* 766 * Do only as much as necessary to compute constant expressions. 767 * Called only if the operator allows folding and all operands are constants. 768 */ 769 static tnode_t * 770 fold(tnode_t *tn) 771 { 772 val_t *v; 773 tspec_t t; 774 bool utyp, ovfl; 775 int64_t sl, sr = 0, q = 0, mask; 776 uint64_t ul, ur = 0; 777 tnode_t *cn; 778 779 v = xcalloc(1, sizeof(*v)); 780 v->v_tspec = tn->tn_type->t_tspec; 781 782 t = tn->tn_left->tn_type->t_tspec; 783 utyp = !is_integer(t) || is_uinteger(t); 784 ul = sl = tn->tn_left->tn_val->v_quad; 785 if (is_binary(tn)) 786 ur = sr = tn->tn_right->tn_val->v_quad; 787 788 mask = value_bits(size_in_bits(t)); 789 ovfl = false; 790 791 switch (tn->tn_op) { 792 case UPLUS: 793 q = sl; 794 break; 795 case UMINUS: 796 q = sl == INT64_MIN ? sl : -sl; 797 if (sl != 0 && msb(q, t) == msb(sl, t)) 798 ovfl = true; 799 break; 800 case COMPL: 801 q = ~sl; 802 break; 803 case MULT: 804 if (utyp) { 805 q = ul * ur; 806 if (q != (q & mask)) 807 ovfl = true; 808 else if ((ul != 0) && ((q / ul) != ur)) 809 ovfl = true; 810 } else { 811 q = sl * sr; 812 if (msb(q, t) != (msb(sl, t) ^ msb(sr, t))) 813 ovfl = true; 814 } 815 break; 816 case DIV: 817 if (sr == 0) { 818 /* division by 0 */ 819 error(139); 820 q = utyp ? -1 : INT64_MAX; 821 } else { 822 q = utyp ? (int64_t)(ul / ur) : sl / sr; 823 } 824 break; 825 case MOD: 826 if (sr == 0) { 827 /* modulus by 0 */ 828 error(140); 829 q = 0; 830 } else { 831 q = utyp ? (int64_t)(ul % ur) : sl % sr; 832 } 833 break; 834 case PLUS: 835 q = utyp ? (int64_t)(ul + ur) : sl + sr; 836 if (msb(sl, t) && msb(sr, t) && !msb(q, t)) 837 ovfl = true; 838 if (!utyp && !msb(sl, t) && !msb(sr, t) && msb(q, t)) 839 ovfl = true; 840 break; 841 case MINUS: 842 q = utyp ? (int64_t)(ul - ur) : sl - sr; 843 if (!utyp && msb(sl, t) && !msb(sr, t) && !msb(q, t)) 844 ovfl = true; 845 if (!msb(sl, t) && msb(sr, t) && msb(q, t)) 846 ovfl = true; 847 break; 848 case SHL: 849 /* TODO: warn about out-of-bounds 'sr'. */ 850 /* TODO: warn about overflow in signed '<<'. */ 851 q = utyp ? (int64_t)(ul << (sr & 63)) : sl << (sr & 63); 852 break; 853 case SHR: 854 /* 855 * The sign must be explicitly extended because 856 * shifts of signed values are implementation dependent. 857 */ 858 /* TODO: warn about out-of-bounds 'sr'. */ 859 q = ul >> (sr & 63); 860 q = convert_integer(q, t, size_in_bits(t) - (int)sr); 861 break; 862 case LT: 863 q = (utyp ? ul < ur : sl < sr) ? 1 : 0; 864 break; 865 case LE: 866 q = (utyp ? ul <= ur : sl <= sr) ? 1 : 0; 867 break; 868 case GE: 869 q = (utyp ? ul >= ur : sl >= sr) ? 1 : 0; 870 break; 871 case GT: 872 q = (utyp ? ul > ur : sl > sr) ? 1 : 0; 873 break; 874 case EQ: 875 q = (utyp ? ul == ur : sl == sr) ? 1 : 0; 876 break; 877 case NE: 878 q = (utyp ? ul != ur : sl != sr) ? 1 : 0; 879 break; 880 case BITAND: 881 q = utyp ? (int64_t)(ul & ur) : sl & sr; 882 break; 883 case BITXOR: 884 q = utyp ? (int64_t)(ul ^ ur) : sl ^ sr; 885 break; 886 case BITOR: 887 q = utyp ? (int64_t)(ul | ur) : sl | sr; 888 break; 889 default: 890 lint_assert(/*CONSTCOND*/false); 891 } 892 893 /* XXX does not work for quads. */ 894 if (ovfl || 895 ((uint64_t)(q | mask) != ~(uint64_t)0 && (q & ~mask) != 0)) { 896 if (hflag) 897 /* integer overflow detected, op '%s' */ 898 warning(141, op_name(tn->tn_op)); 899 } 900 901 v->v_quad = convert_integer(q, t, 0); 902 903 cn = build_constant(tn->tn_type, v); 904 if (tn->tn_left->tn_system_dependent) 905 cn->tn_system_dependent = true; 906 if (is_binary(tn) && tn->tn_right->tn_system_dependent) 907 cn->tn_system_dependent = true; 908 909 return cn; 910 } 911 912 /* 913 * Create a new node for one of the operators POINT and ARROW. 914 */ 915 static tnode_t * 916 build_struct_access(op_t op, bool sys, tnode_t *ln, tnode_t *rn) 917 { 918 tnode_t *ntn, *ctn; 919 bool nolval; 920 921 lint_assert(rn->tn_op == NAME); 922 lint_assert(is_member(rn->tn_sym)); 923 924 /* 925 * Remember if the left operand is an lvalue (structure members 926 * are lvalues if and only if the structure itself is an lvalue). 927 */ 928 nolval = op == POINT && !ln->tn_lvalue; 929 930 if (op == POINT) { 931 ln = build_address(sys, ln, true); 932 } else if (ln->tn_type->t_tspec != PTR) { 933 lint_assert(!allow_c90); 934 lint_assert(is_integer(ln->tn_type->t_tspec)); 935 ln = convert(NOOP, 0, expr_derive_type(gettyp(VOID), PTR), ln); 936 } 937 938 ctn = build_integer_constant(PTRDIFF_TSPEC, 939 rn->tn_sym->u.s_member.sm_offset_in_bits / CHAR_SIZE); 940 941 ntn = new_tnode(PLUS, sys, expr_derive_type(rn->tn_type, PTR), 942 ln, ctn); 943 if (ln->tn_op == CON) 944 ntn = fold(ntn); 945 946 if (rn->tn_type->t_bitfield) { 947 ntn = new_tnode(FSEL, sys, ntn->tn_type->t_subt, ntn, NULL); 948 } else { 949 ntn = new_tnode(INDIR, sys, ntn->tn_type->t_subt, ntn, NULL); 950 } 951 952 if (nolval) 953 ntn->tn_lvalue = false; 954 955 return ntn; 956 } 957 958 /* 959 * Get the size in bytes of type tp->t_subt, as a constant expression of type 960 * ptrdiff_t as seen from the target platform. 961 */ 962 static tnode_t * 963 subt_size_in_bytes(type_t *tp) 964 { 965 int elem, elsz_in_bits; 966 967 lint_assert(tp->t_tspec == PTR); 968 tp = tp->t_subt; 969 970 elem = 1; 971 elsz_in_bits = 0; 972 973 while (tp->t_tspec == ARRAY) { 974 elem *= tp->t_dim; 975 tp = tp->t_subt; 976 } 977 978 switch (tp->t_tspec) { 979 case FUNC: 980 /* pointer to function is not allowed here */ 981 error(110); 982 break; 983 case VOID: 984 /* cannot do pointer arithmetic on operand of unknown size */ 985 gnuism(136); 986 break; 987 case STRUCT: 988 case UNION: 989 if ((elsz_in_bits = tp->t_sou->sou_size_in_bits) == 0) 990 /* cannot do pointer arithmetic on operand of ... */ 991 error(136); 992 break; 993 case ENUM: 994 if (is_incomplete(tp)) { 995 /* cannot do pointer arithmetic on operand of ... */ 996 warning(136); 997 } 998 /* FALLTHROUGH */ 999 default: 1000 if ((elsz_in_bits = size_in_bits(tp->t_tspec)) == 0) { 1001 /* cannot do pointer arithmetic on operand of ... */ 1002 error(136); 1003 } else { 1004 lint_assert(elsz_in_bits != -1); 1005 } 1006 break; 1007 } 1008 1009 if (elem == 0 && elsz_in_bits != 0) { 1010 /* cannot do pointer arithmetic on operand of unknown size */ 1011 error(136); 1012 } 1013 1014 if (elsz_in_bits == 0) 1015 elsz_in_bits = CHAR_SIZE; 1016 1017 return build_integer_constant(PTRDIFF_TSPEC, 1018 (int64_t)(elem * elsz_in_bits / CHAR_SIZE)); 1019 } 1020 1021 /* 1022 * Create a node for INCAFT, INCBEF, DECAFT and DECBEF. 1023 */ 1024 static tnode_t * 1025 build_prepost_incdec(op_t op, bool sys, tnode_t *ln) 1026 { 1027 tnode_t *cn, *ntn; 1028 1029 lint_assert(ln != NULL); 1030 1031 if (ln->tn_type->t_tspec == PTR) { 1032 cn = subt_size_in_bytes(ln->tn_type); 1033 } else { 1034 cn = build_integer_constant(INT, (int64_t)1); 1035 } 1036 ntn = new_tnode(op, sys, ln->tn_type, ln, cn); 1037 1038 return ntn; 1039 } 1040 1041 static void 1042 check_enum_array_index(const tnode_t *ln, const tnode_t *rn) 1043 { 1044 int max_array_index; 1045 int64_t max_enum_value; 1046 const struct sym *ec, *max_ec; 1047 const type_t *lt, *rt; 1048 1049 if (ln->tn_op != ADDR || ln->tn_left->tn_op != NAME) 1050 return; 1051 1052 lt = ln->tn_left->tn_type; 1053 if (lt->t_tspec != ARRAY || lt->t_incomplete_array) 1054 return; 1055 1056 if (rn->tn_op != CVT || !rn->tn_type->t_is_enum) 1057 return; 1058 if (rn->tn_left->tn_op != LOAD) 1059 return; 1060 1061 rt = rn->tn_left->tn_type; 1062 ec = rt->t_enum->en_first_enumerator; 1063 max_ec = ec; 1064 lint_assert(ec != NULL); 1065 for (ec = ec->s_next; ec != NULL; ec = ec->s_next) 1066 if (ec->u.s_enum_constant > max_ec->u.s_enum_constant) 1067 max_ec = ec; 1068 1069 max_enum_value = max_ec->u.s_enum_constant; 1070 lint_assert(INT_MIN <= max_enum_value && max_enum_value <= INT_MAX); 1071 1072 max_array_index = lt->t_dim - 1; 1073 if (max_enum_value == max_array_index) 1074 return; 1075 1076 /* 1077 * If the name of the largest enum constant contains 'MAX' or 'NUM', 1078 * that constant is typically not part of the allowed enum values but 1079 * a marker for the number of actual enum values. 1080 */ 1081 if (max_enum_value == max_array_index + 1 && 1082 (strstr(max_ec->s_name, "MAX") != NULL || 1083 strstr(max_ec->s_name, "max") != NULL || 1084 strstr(max_ec->s_name, "NUM") != NULL || 1085 strstr(max_ec->s_name, "num") != NULL)) 1086 return; 1087 1088 /* maximum value %d of '%s' does not match maximum array index %d */ 1089 warning(348, (int)max_enum_value, type_name(rt), max_array_index); 1090 print_previous_declaration(max_ec); 1091 } 1092 1093 /* 1094 * Create a node for operators PLUS and MINUS. 1095 */ 1096 static tnode_t * 1097 build_plus_minus(op_t op, bool sys, tnode_t *ln, tnode_t *rn) 1098 { 1099 1100 /* If pointer and integer, then pointer to the lhs. */ 1101 if (rn->tn_type->t_tspec == PTR && is_integer(ln->tn_type->t_tspec)) { 1102 tnode_t *tmp = ln; 1103 ln = rn; 1104 rn = tmp; 1105 /* pointer addition has integer on the left-hand side */ 1106 query_message(5); 1107 } 1108 1109 /* pointer +- integer */ 1110 if (ln->tn_type->t_tspec == PTR && rn->tn_type->t_tspec != PTR) { 1111 lint_assert(is_integer(rn->tn_type->t_tspec)); 1112 1113 check_ctype_macro_invocation(ln, rn); 1114 check_enum_array_index(ln, rn); 1115 1116 tnode_t *elsz = subt_size_in_bytes(ln->tn_type); 1117 if (rn->tn_type->t_tspec != elsz->tn_type->t_tspec) 1118 rn = convert(NOOP, 0, elsz->tn_type, rn); 1119 1120 tnode_t *prod = new_tnode(MULT, sys, rn->tn_type, rn, elsz); 1121 if (rn->tn_op == CON) 1122 prod = fold(prod); 1123 1124 return new_tnode(op, sys, ln->tn_type, ln, prod); 1125 } 1126 1127 /* pointer - pointer */ 1128 if (rn->tn_type->t_tspec == PTR) { 1129 lint_assert(ln->tn_type->t_tspec == PTR); 1130 lint_assert(op == MINUS); 1131 1132 type_t *ptrdiff = gettyp(PTRDIFF_TSPEC); 1133 tnode_t *raw_diff = new_tnode(op, sys, ptrdiff, ln, rn); 1134 if (ln->tn_op == CON && rn->tn_op == CON) 1135 raw_diff = fold(raw_diff); 1136 1137 tnode_t *elsz = subt_size_in_bytes(ln->tn_type); 1138 balance(NOOP, &raw_diff, &elsz); 1139 1140 return new_tnode(DIV, sys, ptrdiff, raw_diff, elsz); 1141 } 1142 1143 return new_tnode(op, sys, ln->tn_type, ln, rn); 1144 } 1145 1146 /* 1147 * Create a node for operators SHL and SHR. 1148 */ 1149 static tnode_t * 1150 build_bit_shift(op_t op, bool sys, tnode_t *ln, tnode_t *rn) 1151 { 1152 1153 if (!allow_c90 && rn->tn_type->t_tspec != INT) 1154 rn = convert(NOOP, 0, gettyp(INT), rn); 1155 return new_tnode(op, sys, ln->tn_type, ln, rn); 1156 } 1157 1158 static bool 1159 is_null_pointer(const tnode_t *tn) 1160 { 1161 tspec_t t = tn->tn_type->t_tspec; 1162 1163 return ((t == PTR && tn->tn_type->t_subt->t_tspec == VOID) || 1164 is_integer(t)) 1165 && (tn->tn_op == CON && tn->tn_val->v_quad == 0); 1166 } 1167 1168 /* Return a type based on tp1, with added qualifiers from tp2. */ 1169 static type_t * 1170 merge_qualifiers(type_t *tp1, const type_t *tp2) 1171 { 1172 type_t *ntp, *nstp; 1173 bool c1, c2, v1, v2; 1174 1175 lint_assert(tp1->t_tspec == PTR); 1176 lint_assert(tp2->t_tspec == PTR); 1177 1178 c1 = tp1->t_subt->t_const; 1179 c2 = tp2->t_subt->t_const; 1180 v1 = tp1->t_subt->t_volatile; 1181 v2 = tp2->t_subt->t_volatile; 1182 1183 if (c1 == (c1 | c2) && v1 == (v1 | v2)) 1184 return tp1; 1185 1186 nstp = expr_dup_type(tp1->t_subt); 1187 nstp->t_const |= c2; 1188 nstp->t_volatile |= v2; 1189 1190 ntp = expr_dup_type(tp1); 1191 ntp->t_subt = nstp; 1192 return ntp; 1193 } 1194 1195 /* See C99 6.5.15 "Conditional operator". */ 1196 static tnode_t * 1197 build_colon(bool sys, tnode_t *ln, tnode_t *rn) 1198 { 1199 tspec_t lt, rt; 1200 type_t *tp; 1201 1202 lt = ln->tn_type->t_tspec; 1203 rt = rn->tn_type->t_tspec; 1204 1205 if (is_arithmetic(lt) && is_arithmetic(rt)) { 1206 /* The operands were already balanced in build_binary. */ 1207 tp = ln->tn_type; 1208 } else if (lt == BOOL && rt == BOOL) { 1209 tp = ln->tn_type; 1210 } else if (lt == VOID || rt == VOID) { 1211 tp = gettyp(VOID); 1212 } else if (is_struct_or_union(lt)) { 1213 /* Both types must be identical. */ 1214 lint_assert(is_struct_or_union(rt)); 1215 lint_assert(ln->tn_type->t_sou == rn->tn_type->t_sou); 1216 if (is_incomplete(ln->tn_type)) { 1217 /* unknown operand size, op '%s' */ 1218 error(138, op_name(COLON)); 1219 return NULL; 1220 } 1221 tp = ln->tn_type; 1222 } else if (lt == PTR && is_integer(rt)) { 1223 if (rt != PTRDIFF_TSPEC) 1224 rn = convert(NOOP, 0, gettyp(PTRDIFF_TSPEC), rn); 1225 tp = ln->tn_type; 1226 } else if (rt == PTR && is_integer(lt)) { 1227 if (lt != PTRDIFF_TSPEC) 1228 ln = convert(NOOP, 0, gettyp(PTRDIFF_TSPEC), ln); 1229 tp = rn->tn_type; 1230 } else if (lt == PTR && is_null_pointer(rn)) { 1231 tp = merge_qualifiers(ln->tn_type, rn->tn_type); 1232 } else if (rt == PTR && is_null_pointer(ln)) { 1233 tp = merge_qualifiers(rn->tn_type, ln->tn_type); 1234 } else if (lt == PTR && ln->tn_type->t_subt->t_tspec == VOID) { 1235 tp = merge_qualifiers(ln->tn_type, rn->tn_type); 1236 } else if (rt == PTR && rn->tn_type->t_subt->t_tspec == VOID) { 1237 tp = merge_qualifiers(rn->tn_type, ln->tn_type); 1238 } else { 1239 /* 1240 * XXX For now we simply take the left type. This is 1241 * probably wrong, if one type contains a function prototype 1242 * and the other one, at the same place, only an old-style 1243 * declaration. 1244 */ 1245 tp = merge_qualifiers(ln->tn_type, rn->tn_type); 1246 } 1247 1248 return new_tnode(COLON, sys, tp, ln, rn); 1249 } 1250 1251 /* TODO: check for varargs */ 1252 static bool 1253 is_cast_redundant(const tnode_t *tn) 1254 { 1255 const type_t *ntp = tn->tn_type, *otp = tn->tn_left->tn_type; 1256 tspec_t nt = ntp->t_tspec, ot = otp->t_tspec; 1257 1258 if (nt == BOOL || ot == BOOL) 1259 return nt == BOOL && ot == BOOL; 1260 1261 if (is_integer(nt) && is_integer(ot)) { 1262 unsigned int nw = width_in_bits(ntp), ow = width_in_bits(otp); 1263 if (is_uinteger(nt) == is_uinteger(ot)) 1264 return nw >= ow; 1265 return is_uinteger(ot) && nw > ow; 1266 } 1267 1268 if (is_complex(nt) || is_complex(ot)) 1269 return is_complex(nt) && is_complex(ot) && 1270 size_in_bits(nt) >= size_in_bits(ot); 1271 1272 if (is_floating(nt) && is_floating(ot)) 1273 return size_in_bits(nt) >= size_in_bits(ot); 1274 1275 if (nt == PTR && ot == PTR) { 1276 if (!ntp->t_subt->t_const && otp->t_subt->t_const) 1277 return false; 1278 if (!ntp->t_subt->t_volatile && otp->t_subt->t_volatile) 1279 return false; 1280 1281 if (ntp->t_subt->t_tspec == VOID || 1282 otp->t_subt->t_tspec == VOID || 1283 types_compatible(ntp->t_subt, otp->t_subt, 1284 false, false, NULL)) 1285 return true; 1286 } 1287 1288 return false; 1289 } 1290 1291 /* 1292 * Create a node for an assignment operator (both = and op= ). 1293 */ 1294 static tnode_t * 1295 build_assignment(op_t op, bool sys, tnode_t *ln, tnode_t *rn) 1296 { 1297 tspec_t lt, rt; 1298 tnode_t *ntn, *ctn; 1299 1300 lint_assert(ln != NULL); 1301 lint_assert(rn != NULL); 1302 1303 lt = ln->tn_type->t_tspec; 1304 rt = rn->tn_type->t_tspec; 1305 1306 if ((op == ADDASS || op == SUBASS) && lt == PTR) { 1307 lint_assert(is_integer(rt)); 1308 ctn = subt_size_in_bytes(ln->tn_type); 1309 if (rn->tn_type->t_tspec != ctn->tn_type->t_tspec) 1310 rn = convert(NOOP, 0, ctn->tn_type, rn); 1311 rn = new_tnode(MULT, sys, rn->tn_type, rn, ctn); 1312 if (rn->tn_left->tn_op == CON) 1313 rn = fold(rn); 1314 } 1315 1316 if ((op == ASSIGN || op == RETURN || op == INIT) && 1317 (lt == STRUCT || rt == STRUCT)) { 1318 lint_assert(lt == rt); 1319 lint_assert(ln->tn_type->t_sou == rn->tn_type->t_sou); 1320 if (is_incomplete(ln->tn_type)) { 1321 if (op == RETURN) { 1322 /* cannot return incomplete type */ 1323 error(212); 1324 } else { 1325 /* unknown operand size, op '%s' */ 1326 error(138, op_name(op)); 1327 } 1328 return NULL; 1329 } 1330 } 1331 1332 if (op == SHLASS) { 1333 if (portable_size_in_bits(lt) < portable_size_in_bits(rt)) { 1334 if (hflag) 1335 /* semantics of '%s' change in ANSI C; ... */ 1336 warning(118, "<<="); 1337 } 1338 } else if (op != SHRASS) { 1339 if (op == ASSIGN || lt != PTR) { 1340 if (lt != rt || 1341 (ln->tn_type->t_bitfield && rn->tn_op == CON)) { 1342 rn = convert(op, 0, ln->tn_type, rn); 1343 rt = lt; 1344 } 1345 } 1346 } 1347 1348 if (any_query_enabled && rn->tn_op == CVT && rn->tn_cast && 1349 types_compatible(ln->tn_type, rn->tn_type, false, false, NULL) && 1350 is_cast_redundant(rn)) { 1351 /* redundant cast from '%s' to '%s' before assignment */ 1352 query_message(7, 1353 type_name(rn->tn_left->tn_type), type_name(rn->tn_type)); 1354 } 1355 1356 ntn = new_tnode(op, sys, ln->tn_type, ln, rn); 1357 1358 return ntn; 1359 } 1360 1361 /* 1362 * Create a node for REAL, IMAG 1363 */ 1364 static tnode_t * 1365 build_real_imag(op_t op, bool sys, tnode_t *ln) 1366 { 1367 tnode_t *cn, *ntn; 1368 1369 lint_assert(ln != NULL); 1370 1371 if (ln->tn_op == NAME) { 1372 /* 1373 * This may be too much, but it avoids wrong warnings. 1374 * See d_c99_complex_split.c. 1375 */ 1376 mark_as_used(ln->tn_sym, false, false); 1377 mark_as_set(ln->tn_sym); 1378 } 1379 1380 switch (ln->tn_type->t_tspec) { 1381 case LCOMPLEX: 1382 /* XXX: integer and LDOUBLE don't match. */ 1383 cn = build_integer_constant(LDOUBLE, (int64_t)1); 1384 break; 1385 case DCOMPLEX: 1386 /* XXX: integer and DOUBLE don't match. */ 1387 cn = build_integer_constant(DOUBLE, (int64_t)1); 1388 break; 1389 case FCOMPLEX: 1390 /* XXX: integer and FLOAT don't match. */ 1391 cn = build_integer_constant(FLOAT, (int64_t)1); 1392 break; 1393 default: 1394 /* '__%s__' is illegal for type '%s' */ 1395 error(276, op == REAL ? "real" : "imag", 1396 type_name(ln->tn_type)); 1397 return NULL; 1398 } 1399 ntn = new_tnode(op, sys, cn->tn_type, ln, cn); 1400 ntn->tn_lvalue = true; 1401 1402 return ntn; 1403 } 1404 1405 static bool 1406 is_confusing_precedence(op_t op, op_t lop, bool lparen, op_t rop, bool rparen) 1407 { 1408 1409 if (op == SHL || op == SHR) { 1410 if (!lparen && (lop == PLUS || lop == MINUS)) 1411 return true; 1412 if (!rparen && (rop == PLUS || rop == MINUS)) 1413 return true; 1414 return false; 1415 } 1416 1417 if (op == LOGOR) { 1418 if (!lparen && lop == LOGAND) 1419 return true; 1420 if (!rparen && rop == LOGAND) 1421 return true; 1422 return false; 1423 } 1424 1425 lint_assert(op == BITAND || op == BITXOR || op == BITOR); 1426 if (!lparen && lop != op) { 1427 if (lop == PLUS || lop == MINUS) 1428 return true; 1429 if (lop == BITAND || lop == BITXOR) 1430 return true; 1431 } 1432 if (!rparen && rop != op) { 1433 if (rop == PLUS || rop == MINUS) 1434 return true; 1435 if (rop == BITAND || rop == BITXOR) 1436 return true; 1437 } 1438 return false; 1439 } 1440 1441 /* 1442 * Print a warning if the given node has operands which should be 1443 * parenthesized. 1444 * 1445 * XXX Does not work if an operand is a constant expression. Constant 1446 * expressions are already folded. 1447 */ 1448 static void 1449 check_precedence_confusion(tnode_t *tn) 1450 { 1451 tnode_t *ln, *rn; 1452 1453 if (!hflag) 1454 return; 1455 1456 debug_node(tn); 1457 1458 lint_assert(is_binary(tn)); 1459 for (ln = tn->tn_left; ln->tn_op == CVT; ln = ln->tn_left) 1460 continue; 1461 for (rn = tn->tn_right; rn->tn_op == CVT; rn = rn->tn_left) 1462 continue; 1463 1464 if (is_confusing_precedence(tn->tn_op, 1465 ln->tn_op, ln->tn_parenthesized, 1466 rn->tn_op, rn->tn_parenthesized)) { 1467 /* precedence confusion possible: parenthesize! */ 1468 warning(169); 1469 } 1470 } 1471 1472 /* 1473 * Fold constant nodes, as much as is needed for comparing the value with 0. 1474 */ 1475 static tnode_t * 1476 fold_bool(tnode_t *tn) 1477 { 1478 bool l, r; 1479 val_t *v; 1480 1481 v = xcalloc(1, sizeof(*v)); 1482 v->v_tspec = tn->tn_type->t_tspec; 1483 lint_assert(v->v_tspec == INT || (Tflag && v->v_tspec == BOOL)); 1484 1485 l = constant_is_nonzero(tn->tn_left); 1486 r = is_binary(tn) && constant_is_nonzero(tn->tn_right); 1487 1488 switch (tn->tn_op) { 1489 case NOT: 1490 if (hflag && !constcond_flag) 1491 /* constant argument to '!' */ 1492 warning(239); 1493 v->v_quad = !l ? 1 : 0; 1494 break; 1495 case LOGAND: 1496 v->v_quad = l && r ? 1 : 0; 1497 break; 1498 case LOGOR: 1499 v->v_quad = l || r ? 1 : 0; 1500 break; 1501 default: 1502 lint_assert(/*CONSTCOND*/false); 1503 } 1504 1505 return build_constant(tn->tn_type, v); 1506 } 1507 1508 static ldbl_t 1509 floating_error_value(tspec_t t, ldbl_t lv) 1510 { 1511 if (t == FLOAT) 1512 return lv < 0 ? -FLT_MAX : FLT_MAX; 1513 if (t == DOUBLE) 1514 return lv < 0 ? -DBL_MAX : DBL_MAX; 1515 /* 1516 * When NetBSD is cross-built in MKLINT=yes mode on x86_64 for 1517 * sparc64, tools/lint checks this code while building usr.bin/xlint. 1518 * In that situation, lint uses the preprocessor for sparc64, in which 1519 * the type 'long double' is IEEE-754-binary128, affecting the macro 1520 * LDBL_MAX below. The type 'long double', as well as the strtold 1521 * implementation, comes from the host platform x86_64 though, where 1522 * 'long double' consumes 128 bits as well but only uses 80 of them. 1523 * The exponent range of the two 'long double' types is the same, but 1524 * the maximum finite value differs due to the extended precision on 1525 * sparc64. 1526 * 1527 * To properly handle the data types of the target platform, lint 1528 * would have to implement the floating-point types in a 1529 * platform-independent way, which is not worth the effort, given how 1530 * few programs practically use 'long double'. 1531 */ 1532 /* LINTED 248: floating-point constant out of range */ 1533 ldbl_t max = LDBL_MAX; 1534 return lv < 0 ? -max : max; 1535 } 1536 1537 /* 1538 * Fold constant nodes having operands with floating point type. 1539 */ 1540 static tnode_t * 1541 fold_float(tnode_t *tn) 1542 { 1543 val_t *v; 1544 tspec_t t; 1545 ldbl_t lv, rv = 0; 1546 1547 fpe = 0; 1548 v = xcalloc(1, sizeof(*v)); 1549 v->v_tspec = t = tn->tn_type->t_tspec; 1550 1551 lint_assert(is_floating(t)); 1552 lint_assert(t == tn->tn_left->tn_type->t_tspec); 1553 lint_assert(!is_binary(tn) || t == tn->tn_right->tn_type->t_tspec); 1554 1555 lv = tn->tn_left->tn_val->v_ldbl; 1556 if (is_binary(tn)) 1557 rv = tn->tn_right->tn_val->v_ldbl; 1558 1559 switch (tn->tn_op) { 1560 case UPLUS: 1561 v->v_ldbl = lv; 1562 break; 1563 case UMINUS: 1564 v->v_ldbl = -lv; 1565 break; 1566 case MULT: 1567 v->v_ldbl = lv * rv; 1568 break; 1569 case DIV: 1570 if (rv == 0.0) { 1571 /* division by 0 */ 1572 error(139); 1573 v->v_ldbl = floating_error_value(t, lv); 1574 } else { 1575 v->v_ldbl = lv / rv; 1576 } 1577 break; 1578 case PLUS: 1579 v->v_ldbl = lv + rv; 1580 break; 1581 case MINUS: 1582 v->v_ldbl = lv - rv; 1583 break; 1584 case LT: 1585 v->v_quad = lv < rv ? 1 : 0; 1586 break; 1587 case LE: 1588 v->v_quad = lv <= rv ? 1 : 0; 1589 break; 1590 case GE: 1591 v->v_quad = lv >= rv ? 1 : 0; 1592 break; 1593 case GT: 1594 v->v_quad = lv > rv ? 1 : 0; 1595 break; 1596 case EQ: 1597 v->v_quad = lv == rv ? 1 : 0; 1598 break; 1599 case NE: 1600 v->v_quad = lv != rv ? 1 : 0; 1601 break; 1602 default: 1603 lint_assert(/*CONSTCOND*/false); 1604 } 1605 1606 lint_assert(fpe != 0 || isnan(v->v_ldbl) == 0); 1607 if (is_complex(v->v_tspec)) { 1608 /* 1609 * Don't warn, as lint doesn't model the imaginary part of 1610 * complex numbers. 1611 */ 1612 fpe = 0; 1613 } else if (fpe != 0 || isfinite(v->v_ldbl) == 0 || 1614 (t == FLOAT && 1615 (v->v_ldbl > FLT_MAX || v->v_ldbl < -FLT_MAX)) || 1616 (t == DOUBLE && 1617 (v->v_ldbl > DBL_MAX || v->v_ldbl < -DBL_MAX))) { 1618 /* floating point overflow on operator '%s' */ 1619 warning(142, op_name(tn->tn_op)); 1620 v->v_ldbl = floating_error_value(t, v->v_ldbl); 1621 fpe = 0; 1622 } 1623 1624 return build_constant(tn->tn_type, v); 1625 } 1626 1627 /* 1628 * Create a tree node for a binary operator and its two operands. Also called 1629 * for unary operators; in that case rn is NULL. 1630 * 1631 * Function calls, sizeof and casts are handled elsewhere. 1632 */ 1633 tnode_t * 1634 build_binary(tnode_t *ln, op_t op, bool sys, tnode_t *rn) 1635 { 1636 const mod_t *mp; 1637 tnode_t *ntn; 1638 type_t *rettp; 1639 1640 mp = &modtab[op]; 1641 1642 /* If there was an error in one of the operands, return. */ 1643 if (ln == NULL || (mp->m_binary && rn == NULL)) 1644 return NULL; 1645 1646 /* 1647 * Apply class conversions to the left operand, but only if its 1648 * value is needed or it is compared with zero. 1649 */ 1650 if (mp->m_value_context || mp->m_compares_with_zero) 1651 ln = cconv(ln); 1652 /* 1653 * The right operand is almost always in a test or value context, 1654 * except if it is a struct or union member. 1655 */ 1656 if (mp->m_binary && op != ARROW && op != POINT) 1657 rn = cconv(rn); 1658 1659 /* 1660 * Print some warnings for comparisons of unsigned values with 1661 * constants lower than or equal to null. This must be done 1662 * before promote() because otherwise unsigned char and unsigned 1663 * short would be promoted to int. Types are also tested to be 1664 * CHAR, which would also become int. 1665 */ 1666 if (mp->m_comparison) 1667 check_integer_comparison(op, ln, rn); 1668 1669 if (mp->m_value_context || mp->m_compares_with_zero) 1670 ln = promote(op, false, ln); 1671 if (mp->m_binary && op != ARROW && op != POINT && 1672 op != ASSIGN && op != RETURN && op != INIT) { 1673 rn = promote(op, false, rn); 1674 } 1675 1676 /* 1677 * If the result of the operation is different for signed or 1678 * unsigned operands and one of the operands is signed only in 1679 * ANSI C, print a warning. 1680 */ 1681 if (mp->m_warn_if_left_unsigned_in_c90 && 1682 ln->tn_op == CON && ln->tn_val->v_unsigned_since_c90) { 1683 /* ANSI C treats constant as unsigned, op '%s' */ 1684 warning(218, mp->m_name); 1685 ln->tn_val->v_unsigned_since_c90 = false; 1686 } 1687 if (mp->m_warn_if_right_unsigned_in_c90 && 1688 rn->tn_op == CON && rn->tn_val->v_unsigned_since_c90) { 1689 /* ANSI C treats constant as unsigned, op '%s' */ 1690 warning(218, mp->m_name); 1691 rn->tn_val->v_unsigned_since_c90 = false; 1692 } 1693 1694 /* Make sure both operands are of the same type */ 1695 if (mp->m_balance_operands || (!allow_c90 && (op == SHL || op == SHR))) 1696 balance(op, &ln, &rn); 1697 1698 /* 1699 * Check types for compatibility with the operation and mutual 1700 * compatibility. Return if there are serious problems. 1701 */ 1702 if (!typeok(op, 0, ln, rn)) 1703 return NULL; 1704 1705 /* And now create the node. */ 1706 switch (op) { 1707 case POINT: 1708 case ARROW: 1709 ntn = build_struct_access(op, sys, ln, rn); 1710 break; 1711 case INCAFT: 1712 case DECAFT: 1713 case INCBEF: 1714 case DECBEF: 1715 ntn = build_prepost_incdec(op, sys, ln); 1716 break; 1717 case ADDR: 1718 ntn = build_address(sys, ln, false); 1719 break; 1720 case INDIR: 1721 ntn = new_tnode(INDIR, sys, ln->tn_type->t_subt, ln, NULL); 1722 break; 1723 case PLUS: 1724 case MINUS: 1725 ntn = build_plus_minus(op, sys, ln, rn); 1726 break; 1727 case SHL: 1728 case SHR: 1729 ntn = build_bit_shift(op, sys, ln, rn); 1730 break; 1731 case COLON: 1732 ntn = build_colon(sys, ln, rn); 1733 break; 1734 case ASSIGN: 1735 case MULASS: 1736 case DIVASS: 1737 case MODASS: 1738 case ADDASS: 1739 case SUBASS: 1740 case SHLASS: 1741 case SHRASS: 1742 case ANDASS: 1743 case XORASS: 1744 case ORASS: 1745 case RETURN: 1746 case INIT: 1747 ntn = build_assignment(op, sys, ln, rn); 1748 break; 1749 case COMMA: 1750 case QUEST: 1751 ntn = new_tnode(op, sys, rn->tn_type, ln, rn); 1752 break; 1753 case REAL: 1754 case IMAG: 1755 ntn = build_real_imag(op, sys, ln); 1756 break; 1757 default: 1758 rettp = mp->m_returns_bool 1759 ? gettyp(Tflag ? BOOL : INT) : ln->tn_type; 1760 lint_assert(mp->m_binary == (rn != NULL)); 1761 ntn = new_tnode(op, sys, rettp, ln, rn); 1762 break; 1763 } 1764 1765 /* Return if an error occurred. */ 1766 if (ntn == NULL) 1767 return NULL; 1768 1769 /* Print a warning if precedence confusion is possible */ 1770 if (mp->m_possible_precedence_confusion) 1771 check_precedence_confusion(ntn); 1772 1773 /* 1774 * Print a warning if one of the operands is in a context where 1775 * it is compared with zero and if this operand is a constant. 1776 */ 1777 if (hflag && !constcond_flag && 1778 mp->m_compares_with_zero && 1779 (ln->tn_op == CON || 1780 ((mp->m_binary && op != QUEST) && rn->tn_op == CON)) && 1781 /* XXX: rn->tn_system_dependent should be checked as well */ 1782 !ln->tn_system_dependent) { 1783 /* constant in conditional context */ 1784 warning(161); 1785 } 1786 1787 /* Fold if the operator requires it */ 1788 if (mp->m_fold_constant_operands) { 1789 if (ln->tn_op == CON && (!mp->m_binary || rn->tn_op == CON)) { 1790 if (mp->m_compares_with_zero) { 1791 ntn = fold_bool(ntn); 1792 } else if (is_floating(ntn->tn_type->t_tspec)) { 1793 ntn = fold_float(ntn); 1794 } else { 1795 ntn = fold(ntn); 1796 } 1797 } else if (op == QUEST && ln->tn_op == CON) { 1798 ntn = ln->tn_val->v_quad != 0 1799 ? rn->tn_left : rn->tn_right; 1800 } 1801 } 1802 1803 return ntn; 1804 } 1805 1806 tnode_t * 1807 build_unary(op_t op, bool sys, tnode_t *tn) 1808 { 1809 return build_binary(tn, op, sys, NULL); 1810 } 1811 1812 /* 1813 * Return whether all struct/union members with the same name have the same 1814 * type and offset. 1815 */ 1816 static bool 1817 all_members_compatible(const sym_t *msym) 1818 { 1819 for (const sym_t *csym = msym; 1820 csym != NULL; csym = csym->s_symtab_next) { 1821 if (!is_member(csym)) 1822 continue; 1823 if (strcmp(msym->s_name, csym->s_name) != 0) 1824 continue; 1825 1826 for (const sym_t *sym = csym->s_symtab_next; 1827 sym != NULL; sym = sym->s_symtab_next) { 1828 1829 if (!is_member(sym)) 1830 continue; 1831 if (strcmp(csym->s_name, sym->s_name) != 0) 1832 continue; 1833 if (csym->u.s_member.sm_offset_in_bits != 1834 sym->u.s_member.sm_offset_in_bits) 1835 return false; 1836 1837 bool w = false; 1838 if (!types_compatible(csym->s_type, sym->s_type, 1839 false, false, &w) && !w) 1840 return false; 1841 if (csym->s_bitfield != sym->s_bitfield) 1842 return false; 1843 if (csym->s_bitfield) { 1844 type_t *tp1 = csym->s_type; 1845 type_t *tp2 = sym->s_type; 1846 if (tp1->t_flen != tp2->t_flen) 1847 return false; 1848 if (tp1->t_foffs != tp2->t_foffs) 1849 return false; 1850 } 1851 } 1852 } 1853 return true; 1854 } 1855 1856 /* 1857 * Returns a symbol which has the same name as the msym argument and is a 1858 * member of the struct or union specified by the tn argument. 1859 */ 1860 static sym_t * 1861 struct_or_union_member(tnode_t *tn, op_t op, sym_t *msym) 1862 { 1863 struct_or_union *str; 1864 type_t *tp; 1865 tspec_t t; 1866 1867 /* 1868 * Remove the member if it was unknown until now, which means 1869 * that no defined struct or union has a member with the same name. 1870 */ 1871 if (msym->s_scl == NOSCL) { 1872 /* type '%s' does not have member '%s' */ 1873 error(101, type_name(tn->tn_type), msym->s_name); 1874 rmsym(msym); 1875 msym->s_kind = FMEMBER; 1876 msym->s_scl = STRUCT_MEMBER; 1877 1878 struct_or_union *sou = expr_zero_alloc(sizeof(*sou)); 1879 sou->sou_tag = expr_zero_alloc(sizeof(*sou->sou_tag)); 1880 sou->sou_tag->s_name = unnamed; 1881 1882 msym->u.s_member.sm_sou_type = sou; 1883 /* 1884 * The member sm_offset_in_bits is not needed here since this 1885 * symbol can only be used for error reporting. 1886 */ 1887 return msym; 1888 } 1889 1890 /* Set str to the tag of which msym is expected to be a member. */ 1891 str = NULL; 1892 t = (tp = tn->tn_type)->t_tspec; 1893 if (op == POINT) { 1894 if (is_struct_or_union(t)) 1895 str = tp->t_sou; 1896 } else if (op == ARROW && t == PTR) { 1897 t = (tp = tp->t_subt)->t_tspec; 1898 if (is_struct_or_union(t)) 1899 str = tp->t_sou; 1900 } 1901 1902 /* 1903 * If this struct/union has a member with the name of msym, return it. 1904 */ 1905 if (str != NULL) { 1906 for (sym_t *sym = msym; 1907 sym != NULL; sym = sym->s_symtab_next) { 1908 if (is_member(sym) && 1909 sym->u.s_member.sm_sou_type == str && 1910 strcmp(sym->s_name, msym->s_name) == 0) 1911 return sym; 1912 } 1913 } 1914 1915 bool eq = all_members_compatible(msym); 1916 1917 /* 1918 * Now handle the case in which the left operand refers really 1919 * to a struct/union, but the right operand is not member of it. 1920 */ 1921 if (str != NULL) { 1922 if (eq && !allow_c90) { 1923 /* illegal use of member '%s' */ 1924 warning(102, msym->s_name); 1925 } else { 1926 /* illegal use of member '%s' */ 1927 error(102, msym->s_name); 1928 } 1929 return msym; 1930 } 1931 1932 /* 1933 * Now the left operand of ARROW does not point to a struct/union 1934 * or the left operand of POINT is no struct/union. 1935 */ 1936 if (eq) { 1937 if (op == POINT) { 1938 if (!allow_c90) { 1939 /* left operand of '.' must be struct ... */ 1940 warning(103, type_name(tn->tn_type)); 1941 } else { 1942 /* left operand of '.' must be struct ... */ 1943 error(103, type_name(tn->tn_type)); 1944 } 1945 } else { 1946 if (!allow_c90 && tn->tn_type->t_tspec == PTR) { 1947 /* left operand of '->' must be pointer ... */ 1948 warning(104, type_name(tn->tn_type)); 1949 } else { 1950 /* left operand of '->' must be pointer ... */ 1951 error(104, type_name(tn->tn_type)); 1952 } 1953 } 1954 } else { 1955 if (!allow_c90) { 1956 /* non-unique member requires struct/union %s */ 1957 error(105, op == POINT ? "object" : "pointer"); 1958 } else { 1959 /* unacceptable operand of '%s' */ 1960 error(111, op_name(op)); 1961 } 1962 } 1963 1964 return msym; 1965 } 1966 1967 tnode_t * 1968 build_member_access(tnode_t *ln, op_t op, bool sys, sbuf_t *member) 1969 { 1970 sym_t *msym; 1971 1972 if (ln == NULL) 1973 return NULL; 1974 1975 if (op == ARROW) { 1976 /* must do this before struct_or_union_member is called */ 1977 ln = cconv(ln); 1978 } 1979 msym = struct_or_union_member(ln, op, getsym(member)); 1980 return build_binary(ln, op, sys, build_name(msym, false)); 1981 } 1982 1983 /* 1984 * Perform class conversions. 1985 * 1986 * Arrays of type T are converted into pointers to type T. 1987 * Functions are converted to pointers to functions. 1988 * Lvalues are converted to rvalues. 1989 * 1990 * C99 6.3 "Conversions" 1991 * C99 6.3.2 "Other operands" 1992 * C99 6.3.2.1 "Lvalues, arrays, and function designators" 1993 */ 1994 tnode_t * 1995 cconv(tnode_t *tn) 1996 { 1997 /* 1998 * Array-lvalue (array of type T) is converted into rvalue 1999 * (pointer to type T) 2000 */ 2001 if (tn->tn_type->t_tspec == ARRAY) { 2002 if (!tn->tn_lvalue) { 2003 /* XXX print correct operator */ 2004 /* %soperand of '%s' must be lvalue */ 2005 gnuism(114, "", op_name(ADDR)); 2006 } 2007 tn = new_tnode(ADDR, tn->tn_sys, 2008 expr_derive_type(tn->tn_type->t_subt, PTR), tn, NULL); 2009 } 2010 2011 /* 2012 * Expression of type function (function with return value of type T) 2013 * in rvalue-expression (pointer to function with return value 2014 * of type T) 2015 */ 2016 if (tn->tn_type->t_tspec == FUNC) 2017 tn = build_address(tn->tn_sys, tn, true); 2018 2019 /* lvalue to rvalue */ 2020 if (tn->tn_lvalue) { 2021 type_t *tp = expr_dup_type(tn->tn_type); 2022 /* C99 6.3.2.1p2 sentence 2 says to remove the qualifiers. */ 2023 tp->t_const = tp->t_volatile = false; 2024 tn = new_tnode(LOAD, tn->tn_sys, tp, tn, NULL); 2025 } 2026 2027 return tn; 2028 } 2029 2030 const tnode_t * 2031 before_conversion(const tnode_t *tn) 2032 { 2033 while (tn->tn_op == CVT && !tn->tn_cast) 2034 tn = tn->tn_left; 2035 return tn; 2036 } 2037 2038 /* 2039 * Most errors required by ANSI C are reported in struct_or_union_member(). 2040 * Here we only check for totally wrong things. 2041 */ 2042 static bool 2043 typeok_point(const tnode_t *ln, const type_t *ltp, tspec_t lt) 2044 { 2045 if (is_struct_or_union(lt)) 2046 return true; 2047 2048 if (lt == FUNC || lt == VOID || ltp->t_bitfield) 2049 goto wrong; 2050 2051 /* 2052 * Some C dialects from before C90 tolerated any lvalue on the 2053 * left-hand side of the '.' operator, allowing things like 2054 * char st[100]; st.st_mtime, assuming that the member 'st_mtime' 2055 * only occurred in a single struct; see typeok_arrow. 2056 */ 2057 if (ln->tn_lvalue) 2058 return true; 2059 2060 wrong: 2061 /* With allow_c90 we already got an error */ 2062 if (!allow_c90) 2063 /* unacceptable operand of '%s' */ 2064 error(111, op_name(POINT)); 2065 2066 return false; 2067 } 2068 2069 static bool 2070 typeok_arrow(tspec_t lt) 2071 { 2072 /* 2073 * C1978 Appendix A 14.1 says: <quote>In fact, any lvalue is allowed 2074 * before '.', and that lvalue is then assumed to have the form of 2075 * the structure of which the name of the right is a member. [...] 2076 * Such constructions are non-portable.</quote> 2077 */ 2078 if (lt == PTR || (!allow_c90 && is_integer(lt))) 2079 return true; 2080 2081 /* With allow_c90 we already got an error */ 2082 if (!allow_c90) 2083 /* unacceptable operand of '%s' */ 2084 error(111, op_name(ARROW)); 2085 return false; 2086 } 2087 2088 static bool 2089 typeok_incdec(op_t op, const tnode_t *tn, const type_t *tp) 2090 { 2091 /* operand has scalar type (checked in typeok) */ 2092 if (!tn->tn_lvalue) { 2093 if (tn->tn_op == CVT && tn->tn_cast && 2094 tn->tn_left->tn_op == LOAD) { 2095 /* a cast does not yield an lvalue */ 2096 error(163); 2097 } 2098 /* %soperand of '%s' must be lvalue */ 2099 error(114, "", op_name(op)); 2100 return false; 2101 } 2102 if (tp->t_const && allow_c90) { 2103 /* %soperand of '%s' must be modifiable lvalue */ 2104 warning(115, "", op_name(op)); 2105 } 2106 return true; 2107 } 2108 2109 static bool 2110 typeok_address(const mod_t *mp, 2111 const tnode_t *tn, const type_t *tp, tspec_t t) 2112 { 2113 if (t == ARRAY || t == FUNC) { 2114 /* ok, a warning comes later (in build_address()) */ 2115 } else if (!tn->tn_lvalue) { 2116 if (tn->tn_op == CVT && tn->tn_cast && 2117 tn->tn_left->tn_op == LOAD) { 2118 /* a cast does not yield an lvalue */ 2119 error(163); 2120 } 2121 /* %soperand of '%s' must be lvalue */ 2122 error(114, "", mp->m_name); 2123 return false; 2124 } else if (is_scalar(t)) { 2125 if (tp->t_bitfield) { 2126 /* cannot take address of bit-field */ 2127 error(112); 2128 return false; 2129 } 2130 } else if (t != STRUCT && t != UNION) { 2131 /* unacceptable operand of '%s' */ 2132 error(111, mp->m_name); 2133 return false; 2134 } 2135 if (tn->tn_op == NAME && tn->tn_sym->s_register) { 2136 /* cannot take address of register '%s' */ 2137 error(113, tn->tn_sym->s_name); 2138 return false; 2139 } 2140 return true; 2141 } 2142 2143 static bool 2144 typeok_indir(const type_t *tp, tspec_t t) 2145 { 2146 2147 if (t != PTR) { 2148 /* cannot dereference non-pointer type '%s' */ 2149 error(96, type_name(tp)); 2150 return false; 2151 } 2152 return true; 2153 } 2154 2155 static void 2156 warn_incompatible_types(op_t op, 2157 const type_t *ltp, tspec_t lt, 2158 const type_t *rtp, tspec_t rt) 2159 { 2160 const mod_t *mp = &modtab[op]; 2161 2162 if (lt == VOID || (mp->m_binary && rt == VOID)) { 2163 /* void type illegal in expression */ 2164 error(109); 2165 } else if (op == ASSIGN) { 2166 /* cannot assign to '%s' from '%s' */ 2167 error(171, type_name(ltp), type_name(rtp)); 2168 } else if (mp->m_binary) { 2169 /* operands of '%s' have incompatible types '%s' and '%s' */ 2170 error(107, mp->m_name, tspec_name(lt), tspec_name(rt)); 2171 } else { 2172 lint_assert(rt == NOTSPEC); 2173 /* operand of '%s' has invalid type '%s' */ 2174 error(108, mp->m_name, type_name(ltp)); 2175 } 2176 } 2177 2178 static bool 2179 typeok_plus(op_t op, 2180 const type_t *ltp, tspec_t lt, 2181 const type_t *rtp, tspec_t rt) 2182 { 2183 /* operands have scalar types (checked in typeok) */ 2184 if ((lt == PTR && !is_integer(rt)) || (rt == PTR && !is_integer(lt))) { 2185 warn_incompatible_types(op, ltp, lt, rtp, rt); 2186 return false; 2187 } 2188 return true; 2189 } 2190 2191 static bool 2192 typeok_minus(op_t op, 2193 const type_t *ltp, tspec_t lt, 2194 const type_t *rtp, tspec_t rt) 2195 { 2196 /* operands have scalar types (checked in typeok) */ 2197 if ((lt == PTR && rt != PTR && !is_integer(rt)) || 2198 (lt != PTR && rt == PTR)) { 2199 warn_incompatible_types(op, ltp, lt, rtp, rt); 2200 return false; 2201 } 2202 if (lt == PTR && rt == PTR && 2203 !types_compatible(ltp->t_subt, rtp->t_subt, true, false, NULL)) { 2204 /* illegal pointer subtraction */ 2205 error(116); 2206 } 2207 return true; 2208 } 2209 2210 static void 2211 typeok_shr(const mod_t *mp, 2212 const tnode_t *ln, tspec_t lt, 2213 const tnode_t *rn, tspec_t rt) 2214 { 2215 tspec_t olt, ort; 2216 2217 olt = before_conversion(ln)->tn_type->t_tspec; 2218 ort = before_conversion(rn)->tn_type->t_tspec; 2219 2220 /* operands have integer types (checked in typeok) */ 2221 if (pflag && !is_uinteger(olt)) { 2222 integer_constraints lc = ic_expr(ln); 2223 if (!ic_maybe_signed(ln->tn_type, &lc)) 2224 return; 2225 2226 /* 2227 * The left operand is signed. This means that 2228 * the operation is (possibly) nonportable. 2229 */ 2230 if (ln->tn_op != CON) { 2231 /* bitwise '%s' on signed value possibly nonportable */ 2232 warning(117, mp->m_name); 2233 } else if (ln->tn_val->v_quad < 0) { 2234 /* bitwise '%s' on signed value nonportable */ 2235 warning(120, mp->m_name); 2236 } 2237 } else if (allow_trad && allow_c90 && 2238 !is_uinteger(olt) && is_uinteger(ort)) { 2239 /* The left operand would become unsigned in traditional C. */ 2240 if (hflag && (ln->tn_op != CON || ln->tn_val->v_quad < 0)) { 2241 /* semantics of '%s' change in ANSI C; use ... */ 2242 warning(118, mp->m_name); 2243 } 2244 } else if (allow_trad && allow_c90 && 2245 !is_uinteger(olt) && !is_uinteger(ort) && 2246 portable_size_in_bits(lt) < portable_size_in_bits(rt)) { 2247 /* 2248 * In traditional C the left operand would be extended 2249 * (possibly sign-extended) and then shifted. 2250 */ 2251 if (hflag && (ln->tn_op != CON || ln->tn_val->v_quad < 0)) { 2252 /* semantics of '%s' change in ANSI C; use ... */ 2253 warning(118, mp->m_name); 2254 } 2255 } 2256 } 2257 2258 static void 2259 typeok_shl(const mod_t *mp, tspec_t lt, tspec_t rt) 2260 { 2261 /* 2262 * C90 does not perform balancing for shift operations, 2263 * but traditional C does. If the width of the right operand 2264 * is greater than the width of the left operand, then in 2265 * traditional C the left operand would be extended to the 2266 * width of the right operand. For SHL this may result in 2267 * different results. 2268 */ 2269 if (portable_size_in_bits(lt) < portable_size_in_bits(rt)) { 2270 /* 2271 * XXX If both operands are constant, make sure 2272 * that there is really a difference between 2273 * ANSI C and traditional C. 2274 */ 2275 if (hflag && !allow_c99) 2276 /* semantics of '%s' change in ANSI C; use ... */ 2277 warning(118, mp->m_name); 2278 } 2279 } 2280 2281 static void 2282 typeok_shift(const type_t *ltp, tspec_t lt, const tnode_t *rn, tspec_t rt) 2283 { 2284 if (rn->tn_op != CON) 2285 return; 2286 2287 if (!is_uinteger(rt) && rn->tn_val->v_quad < 0) { 2288 /* negative shift */ 2289 warning(121); 2290 } else if ((uint64_t)rn->tn_val->v_quad == 2291 (uint64_t)size_in_bits(lt)) { 2292 /* shift amount %u equals bit-size of '%s' */ 2293 warning(267, (unsigned)rn->tn_val->v_quad, type_name(ltp)); 2294 } else if ((uint64_t)rn->tn_val->v_quad > (uint64_t)size_in_bits(lt)) { 2295 /* shift amount %llu is greater than bit-size %llu of '%s' */ 2296 warning(122, (unsigned long long)rn->tn_val->v_quad, 2297 (unsigned long long)size_in_bits(lt), 2298 tspec_name(lt)); 2299 } 2300 } 2301 2302 static bool 2303 is_typeok_eq(const tnode_t *ln, tspec_t lt, const tnode_t *rn, tspec_t rt) 2304 { 2305 if (lt == PTR && is_null_pointer(rn)) 2306 return true; 2307 if (rt == PTR && is_null_pointer(ln)) 2308 return true; 2309 return false; 2310 } 2311 2312 /* 2313 * Called if incompatible pointer types are detected. 2314 * Print an appropriate warning. 2315 */ 2316 static void 2317 warn_incompatible_pointers(const mod_t *mp, 2318 const type_t *ltp, const type_t *rtp) 2319 { 2320 lint_assert(ltp->t_tspec == PTR); 2321 lint_assert(rtp->t_tspec == PTR); 2322 2323 tspec_t lt = ltp->t_subt->t_tspec; 2324 tspec_t rt = rtp->t_subt->t_tspec; 2325 2326 if (is_struct_or_union(lt) && is_struct_or_union(rt)) { 2327 if (mp == NULL) { 2328 /* illegal structure pointer combination */ 2329 warning(244); 2330 } else { 2331 /* incompatible structure pointers: '%s' '%s' '%s' */ 2332 warning(245, type_name(ltp), mp->m_name, type_name(rtp)); 2333 } 2334 } else { 2335 if (mp == NULL) { 2336 /* illegal combination of '%s' and '%s' */ 2337 warning(184, type_name(ltp), type_name(rtp)); 2338 } else { 2339 /* illegal combination of '%s' and '%s', op '%s' */ 2340 warning(124, 2341 type_name(ltp), type_name(rtp), mp->m_name); 2342 } 2343 } 2344 } 2345 2346 static void 2347 check_pointer_comparison(op_t op, const tnode_t *ln, const tnode_t *rn) 2348 { 2349 type_t *ltp = ln->tn_type, *rtp = rn->tn_type; 2350 tspec_t lst = ltp->t_subt->t_tspec, rst = rtp->t_subt->t_tspec; 2351 2352 if (lst == VOID || rst == VOID) { 2353 /* TODO: C99 behaves like C90 here. */ 2354 if ((!allow_trad && !allow_c99) && 2355 (lst == FUNC || rst == FUNC)) { 2356 /* (void *)0 is already handled in typeok() */ 2357 const char *lsts, *rsts; 2358 *(lst == FUNC ? &lsts : &rsts) = "function pointer"; 2359 *(lst == VOID ? &lsts : &rsts) = "'void *'"; 2360 /* ANSI C forbids comparison of %s with %s */ 2361 warning(274, lsts, rsts); 2362 } 2363 return; 2364 } 2365 2366 if (!types_compatible(ltp->t_subt, rtp->t_subt, true, false, NULL)) { 2367 warn_incompatible_pointers(&modtab[op], ltp, rtp); 2368 return; 2369 } 2370 2371 if (lst == FUNC && rst == FUNC) { 2372 /* TODO: C99 behaves like C90 here, see C99 6.5.8p2. */ 2373 if ((!allow_trad && !allow_c99) && op != EQ && op != NE) 2374 /* ANSI C forbids ordered comparisons of ... */ 2375 warning(125); 2376 } 2377 } 2378 2379 static bool 2380 typeok_compare(op_t op, 2381 const tnode_t *ln, const type_t *ltp, tspec_t lt, 2382 const tnode_t *rn, const type_t *rtp, tspec_t rt) 2383 { 2384 if (lt == PTR && rt == PTR) { 2385 check_pointer_comparison(op, ln, rn); 2386 return true; 2387 } 2388 2389 if (lt != PTR && rt != PTR) 2390 return true; 2391 2392 if (!is_integer(lt) && !is_integer(rt)) { 2393 warn_incompatible_types(op, ltp, lt, rtp, rt); 2394 return false; 2395 } 2396 2397 const char *lx = lt == PTR ? "pointer" : "integer"; 2398 const char *rx = rt == PTR ? "pointer" : "integer"; 2399 /* illegal combination of %s '%s' and %s '%s', op '%s' */ 2400 warning(123, lx, type_name(ltp), rx, type_name(rtp), op_name(op)); 2401 return true; 2402 } 2403 2404 static bool 2405 typeok_quest(tspec_t lt, const tnode_t *rn) 2406 { 2407 if (!is_scalar(lt)) { 2408 /* first operand must have scalar type, op ? : */ 2409 error(170); 2410 return false; 2411 } 2412 lint_assert(before_conversion(rn)->tn_op == COLON); 2413 return true; 2414 } 2415 2416 static void 2417 typeok_colon_pointer(const mod_t *mp, const type_t *ltp, const type_t *rtp) 2418 { 2419 type_t *lstp = ltp->t_subt; 2420 type_t *rstp = rtp->t_subt; 2421 tspec_t lst = lstp->t_tspec; 2422 tspec_t rst = rstp->t_tspec; 2423 2424 if ((lst == VOID && rst == FUNC) || (lst == FUNC && rst == VOID)) { 2425 /* (void *)0 is handled in typeok_colon */ 2426 /* TODO: C99 behaves like C90 here. */ 2427 if (!allow_trad && !allow_c99) 2428 /* ANSI C forbids conversion of %s to %s, op %s */ 2429 warning(305, "function pointer", "'void *'", 2430 mp->m_name); 2431 return; 2432 } 2433 2434 if (pointer_types_are_compatible(lstp, rstp, true)) 2435 return; 2436 if (!types_compatible(lstp, rstp, true, false, NULL)) 2437 warn_incompatible_pointers(mp, ltp, rtp); 2438 } 2439 2440 static bool 2441 typeok_colon(const mod_t *mp, 2442 const tnode_t *ln, const type_t *ltp, tspec_t lt, 2443 const tnode_t *rn, const type_t *rtp, tspec_t rt) 2444 { 2445 2446 if (is_arithmetic(lt) && is_arithmetic(rt)) 2447 return true; 2448 if (lt == BOOL && rt == BOOL) 2449 return true; 2450 2451 if (lt == STRUCT && rt == STRUCT && ltp->t_sou == rtp->t_sou) 2452 return true; 2453 if (lt == UNION && rt == UNION && ltp->t_sou == rtp->t_sou) 2454 return true; 2455 2456 if (lt == PTR && is_null_pointer(rn)) 2457 return true; 2458 if (rt == PTR && is_null_pointer(ln)) 2459 return true; 2460 2461 if ((lt == PTR && is_integer(rt)) || (is_integer(lt) && rt == PTR)) { 2462 const char *lx = lt == PTR ? "pointer" : "integer"; 2463 const char *rx = rt == PTR ? "pointer" : "integer"; 2464 /* illegal combination of %s '%s' and %s '%s', op '%s' */ 2465 warning(123, lx, type_name(ltp), 2466 rx, type_name(rtp), mp->m_name); 2467 return true; 2468 } 2469 2470 if (lt == VOID || rt == VOID) { 2471 if (lt != VOID || rt != VOID) 2472 /* incompatible types '%s' and '%s' in conditional */ 2473 warning(126, type_name(ltp), type_name(rtp)); 2474 return true; 2475 } 2476 2477 if (lt == PTR && rt == PTR) { 2478 typeok_colon_pointer(mp, ltp, rtp); 2479 return true; 2480 } 2481 2482 /* incompatible types '%s' and '%s' in conditional */ 2483 error(126, type_name(ltp), type_name(rtp)); 2484 return false; 2485 } 2486 2487 /* 2488 * Returns true if the given structure or union has a constant member 2489 * (maybe recursively). 2490 */ 2491 static bool 2492 has_constant_member(const type_t *tp) 2493 { 2494 lint_assert(is_struct_or_union(tp->t_tspec)); 2495 2496 for (sym_t *m = tp->t_sou->sou_first_member; 2497 m != NULL; m = m->s_next) { 2498 const type_t *mtp = m->s_type; 2499 if (mtp->t_const) 2500 return true; 2501 if (is_struct_or_union(mtp->t_tspec) && 2502 has_constant_member(mtp)) 2503 return true; 2504 } 2505 return false; 2506 } 2507 2508 static bool 2509 typeok_assign(op_t op, const tnode_t *ln, const type_t *ltp, tspec_t lt) 2510 { 2511 if (op == RETURN || op == INIT || op == FARG) 2512 return true; 2513 2514 if (!ln->tn_lvalue) { 2515 if (ln->tn_op == CVT && ln->tn_cast && 2516 ln->tn_left->tn_op == LOAD) { 2517 /* a cast does not yield an lvalue */ 2518 error(163); 2519 } 2520 /* %soperand of '%s' must be lvalue */ 2521 error(114, "left ", op_name(op)); 2522 return false; 2523 } else if (ltp->t_const || (is_struct_or_union(lt) && 2524 has_constant_member(ltp))) { 2525 if (allow_c90) 2526 /* %soperand of '%s' must be modifiable lvalue */ 2527 warning(115, "left ", op_name(op)); 2528 } 2529 return true; 2530 } 2531 2532 /* Check the types using the information from modtab[]. */ 2533 static bool 2534 typeok_scalar(op_t op, const mod_t *mp, 2535 const type_t *ltp, tspec_t lt, 2536 const type_t *rtp, tspec_t rt) 2537 { 2538 if (mp->m_takes_bool && lt == BOOL && rt == BOOL) 2539 return true; 2540 if (mp->m_requires_integer) { 2541 if (!is_integer(lt) || (mp->m_binary && !is_integer(rt))) { 2542 warn_incompatible_types(op, ltp, lt, rtp, rt); 2543 return false; 2544 } 2545 } else if (mp->m_requires_integer_or_complex) { 2546 if ((!is_integer(lt) && !is_complex(lt)) || 2547 (mp->m_binary && (!is_integer(rt) && !is_complex(rt)))) { 2548 warn_incompatible_types(op, ltp, lt, rtp, rt); 2549 return false; 2550 } 2551 } else if (mp->m_requires_scalar) { 2552 if (!is_scalar(lt) || (mp->m_binary && !is_scalar(rt))) { 2553 warn_incompatible_types(op, ltp, lt, rtp, rt); 2554 return false; 2555 } 2556 } else if (mp->m_requires_arith) { 2557 if (!is_arithmetic(lt) || 2558 (mp->m_binary && !is_arithmetic(rt))) { 2559 warn_incompatible_types(op, ltp, lt, rtp, rt); 2560 return false; 2561 } 2562 } 2563 return true; 2564 } 2565 2566 static void 2567 check_assign_void_pointer(op_t op, int arg, 2568 tspec_t lt, tspec_t lst, 2569 tspec_t rt, tspec_t rst) 2570 { 2571 2572 if (!(lt == PTR && rt == PTR && (lst == VOID || rst == VOID))) 2573 return; 2574 /* two pointers, at least one pointer to void */ 2575 2576 /* TODO: C99 behaves like C90 here. */ 2577 if (!((!allow_trad && !allow_c99) && (lst == FUNC || rst == FUNC))) 2578 return; 2579 /* comb. of ptr to func and ptr to void */ 2580 2581 const char *lts, *rts; 2582 *(lst == FUNC ? <s : &rts) = "function pointer"; 2583 *(lst == VOID ? <s : &rts) = "'void *'"; 2584 2585 switch (op) { 2586 case INIT: 2587 case RETURN: 2588 /* ANSI C forbids conversion of %s to %s */ 2589 warning(303, rts, lts); 2590 break; 2591 case FARG: 2592 /* ANSI C forbids conversion of %s to %s, arg #%d */ 2593 warning(304, rts, lts, arg); 2594 break; 2595 default: 2596 /* ANSI C forbids conversion of %s to %s, op %s */ 2597 warning(305, rts, lts, op_name(op)); 2598 break; 2599 } 2600 } 2601 2602 static bool 2603 is_direct_function_call(const tnode_t *tn, const char **out_name) 2604 { 2605 2606 if (!(tn->tn_op == CALL && 2607 tn->tn_left->tn_op == ADDR && 2608 tn->tn_left->tn_left->tn_op == NAME)) 2609 return false; 2610 2611 *out_name = tn->tn_left->tn_left->tn_sym->s_name; 2612 return true; 2613 } 2614 2615 static bool 2616 is_unconst_function(const char *name) 2617 { 2618 2619 return strcmp(name, "memchr") == 0 || 2620 strcmp(name, "strchr") == 0 || 2621 strcmp(name, "strpbrk") == 0 || 2622 strcmp(name, "strrchr") == 0 || 2623 strcmp(name, "strstr") == 0; 2624 } 2625 2626 static bool 2627 is_const_char_pointer(const tnode_t *tn) 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 const type_t *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 = tn->tn_right; 2655 if (an == NULL) 2656 return false; 2657 2658 while (an->tn_right != NULL) 2659 an = an->tn_right; 2660 return is_const_char_pointer(an->tn_left); 2661 } 2662 2663 static bool 2664 is_const_pointer(const tnode_t *tn) 2665 { 2666 const type_t *tp = before_conversion(tn)->tn_type; 2667 return tp->t_tspec == PTR && tp->t_subt->t_const; 2668 } 2669 2670 static bool 2671 is_second_arg_const_pointer(const tnode_t *tn) 2672 { 2673 const tnode_t *an = tn->tn_right; 2674 if (an == NULL || an->tn_right == NULL) 2675 return false; 2676 2677 while (an->tn_right->tn_right != NULL) 2678 an = an->tn_right; 2679 return is_const_pointer(an->tn_left); 2680 } 2681 2682 static void 2683 check_unconst_function(const type_t *lstp, const tnode_t *rn) 2684 { 2685 const char *function_name; 2686 2687 if (lstp->t_tspec == CHAR && !lstp->t_const && 2688 is_direct_function_call(rn, &function_name) && 2689 is_unconst_function(function_name) && 2690 is_first_arg_const_char_pointer(rn)) { 2691 /* call to '%s' effectively discards 'const' from argument */ 2692 warning(346, function_name); 2693 } 2694 2695 if (!lstp->t_const && 2696 is_direct_function_call(rn, &function_name) && 2697 strcmp(function_name, "bsearch") == 0 && 2698 is_second_arg_const_pointer(rn)) { 2699 /* call to '%s' effectively discards 'const' from argument */ 2700 warning(346, function_name); 2701 } 2702 } 2703 2704 static bool 2705 check_assign_void_pointer_compat(op_t op, int arg, 2706 const type_t *const ltp, tspec_t const lt, 2707 const type_t *const lstp, tspec_t const lst, 2708 const tnode_t *const rn, 2709 const type_t *const rtp, tspec_t const rt, 2710 const type_t *const rstp, tspec_t const rst) 2711 { 2712 if (!(lt == PTR && rt == PTR && (lst == VOID || rst == VOID || 2713 types_compatible(lstp, rstp, 2714 true, false, NULL)))) 2715 return false; 2716 2717 /* compatible pointer types (qualifiers ignored) */ 2718 if (allow_c90 && 2719 ((!lstp->t_const && rstp->t_const) || 2720 (!lstp->t_volatile && rstp->t_volatile))) { 2721 /* left side has not all qualifiers of right */ 2722 switch (op) { 2723 case INIT: 2724 case RETURN: 2725 /* incompatible pointer types to '%s' and '%s' */ 2726 warning(182, type_name(lstp), type_name(rstp)); 2727 break; 2728 case FARG: 2729 /* converting '%s' to incompatible '%s' ... */ 2730 warning(153, 2731 type_name(rtp), type_name(ltp), arg); 2732 break; 2733 default: 2734 /* operands of '%s' have incompatible pointer ... */ 2735 warning(128, op_name(op), 2736 type_name(lstp), type_name(rstp)); 2737 break; 2738 } 2739 } 2740 2741 if (allow_c90) 2742 check_unconst_function(lstp, rn); 2743 2744 return true; 2745 } 2746 2747 static bool 2748 check_assign_pointer_integer(op_t op, int arg, 2749 const type_t *const ltp, tspec_t const lt, 2750 const type_t *const rtp, tspec_t const rt) 2751 { 2752 const char *lx, *rx; 2753 2754 if (!((lt == PTR && is_integer(rt)) || (is_integer(lt) && rt == PTR))) 2755 return false; 2756 2757 lx = lt == PTR ? "pointer" : "integer"; 2758 rx = rt == PTR ? "pointer" : "integer"; 2759 2760 switch (op) { 2761 case INIT: 2762 case RETURN: 2763 /* illegal combination of %s '%s' and %s '%s' */ 2764 warning(183, lx, type_name(ltp), rx, type_name(rtp)); 2765 break; 2766 case FARG: 2767 /* illegal combination of %s '%s' and %s '%s', arg #%d */ 2768 warning(154, 2769 lx, type_name(ltp), rx, type_name(rtp), arg); 2770 break; 2771 default: 2772 /* illegal combination of %s '%s' and %s '%s', op '%s' */ 2773 warning(123, 2774 lx, type_name(ltp), rx, type_name(rtp), op_name(op)); 2775 break; 2776 } 2777 return true; 2778 } 2779 2780 static bool 2781 check_assign_pointer(op_t op, int arg, 2782 const type_t *ltp, tspec_t lt, 2783 const type_t *rtp, tspec_t rt) 2784 { 2785 if (!(lt == PTR && rt == PTR)) 2786 return false; 2787 2788 switch (op) { 2789 case RETURN: 2790 warn_incompatible_pointers(NULL, ltp, rtp); 2791 break; 2792 case FARG: 2793 /* converting '%s' to incompatible '%s' for ... */ 2794 warning(153, type_name(rtp), type_name(ltp), arg); 2795 break; 2796 default: 2797 warn_incompatible_pointers(&modtab[op], ltp, rtp); 2798 break; 2799 } 2800 return true; 2801 } 2802 2803 static void 2804 warn_assign(op_t op, int arg, 2805 const type_t *ltp, tspec_t lt, 2806 const type_t *rtp, tspec_t rt) 2807 { 2808 switch (op) { 2809 case INIT: 2810 /* cannot initialize '%s' from '%s' */ 2811 error(185, type_name(ltp), type_name(rtp)); 2812 break; 2813 case RETURN: 2814 /* function has return type '%s' but returns '%s' */ 2815 error(211, type_name(ltp), type_name(rtp)); 2816 break; 2817 case FARG: 2818 /* passing '%s' to incompatible '%s', arg #%d */ 2819 warning(155, type_name(rtp), type_name(ltp), arg); 2820 break; 2821 default: 2822 warn_incompatible_types(op, ltp, lt, rtp, rt); 2823 break; 2824 } 2825 } 2826 2827 /* 2828 * Checks type compatibility for ASSIGN, INIT, FARG and RETURN 2829 * and prints warnings/errors if necessary. 2830 * Returns whether the types are (almost) compatible. 2831 */ 2832 static bool 2833 check_assign_types_compatible(op_t op, int arg, 2834 const tnode_t *ln, const tnode_t *rn) 2835 { 2836 tspec_t lt, rt, lst = NOTSPEC, rst = NOTSPEC; 2837 type_t *ltp, *rtp, *lstp = NULL, *rstp = NULL; 2838 2839 if ((lt = (ltp = ln->tn_type)->t_tspec) == PTR) 2840 lst = (lstp = ltp->t_subt)->t_tspec; 2841 if ((rt = (rtp = rn->tn_type)->t_tspec) == PTR) 2842 rst = (rstp = rtp->t_subt)->t_tspec; 2843 2844 if (lt == BOOL && is_scalar(rt)) /* C99 6.3.1.2 */ 2845 return true; 2846 2847 if (is_arithmetic(lt) && (is_arithmetic(rt) || rt == BOOL)) 2848 return true; 2849 2850 if (is_struct_or_union(lt) && is_struct_or_union(rt)) 2851 /* both are struct or union */ 2852 return ltp->t_sou == rtp->t_sou; 2853 2854 /* a null pointer may be assigned to any pointer */ 2855 if (lt == PTR && is_null_pointer(rn)) 2856 return true; 2857 2858 check_assign_void_pointer(op, arg, lt, lst, rt, rst); 2859 2860 if (check_assign_void_pointer_compat(op, arg, 2861 ltp, lt, lstp, lst, rn, rtp, rt, rstp, rst)) 2862 return true; 2863 2864 if (check_assign_pointer_integer(op, arg, ltp, lt, rtp, rt)) 2865 return true; 2866 2867 if (check_assign_pointer(op, arg, ltp, lt, rtp, rt)) 2868 return true; 2869 2870 warn_assign(op, arg, ltp, lt, rtp, rt); 2871 return false; 2872 } 2873 2874 static bool 2875 has_side_effect(const tnode_t *tn) /* NOLINT(misc-no-recursion) */ 2876 { 2877 op_t op = tn->tn_op; 2878 2879 if (modtab[op].m_has_side_effect) 2880 return true; 2881 2882 if (op == CVT && tn->tn_type->t_tspec == VOID) 2883 return has_side_effect(tn->tn_left); 2884 2885 /* XXX: Why not has_side_effect(tn->tn_left) as well? */ 2886 if (op == LOGAND || op == LOGOR) 2887 return has_side_effect(tn->tn_right); 2888 2889 /* XXX: Why not has_side_effect(tn->tn_left) as well? */ 2890 if (op == QUEST) 2891 return has_side_effect(tn->tn_right); 2892 2893 if (op == COLON || op == COMMA) { 2894 return has_side_effect(tn->tn_left) || 2895 has_side_effect(tn->tn_right); 2896 } 2897 2898 return false; 2899 } 2900 2901 static bool 2902 is_void_cast(const tnode_t *tn) 2903 { 2904 2905 return tn->tn_op == CVT && tn->tn_cast && 2906 tn->tn_type->t_tspec == VOID; 2907 } 2908 2909 static bool 2910 is_local_symbol(const tnode_t *tn) 2911 { 2912 2913 return tn->tn_op == LOAD && 2914 tn->tn_left->tn_op == NAME && 2915 tn->tn_left->tn_sym->s_scl == AUTO; 2916 } 2917 2918 static bool 2919 is_int_constant_zero(const tnode_t *tn) 2920 { 2921 2922 return tn->tn_op == CON && 2923 tn->tn_type->t_tspec == INT && 2924 tn->tn_val->v_quad == 0; 2925 } 2926 2927 static void 2928 check_null_effect(const tnode_t *tn) 2929 { 2930 2931 if (hflag && 2932 !has_side_effect(tn) && 2933 !(is_void_cast(tn) && is_local_symbol(tn->tn_left)) && 2934 !(is_void_cast(tn) && is_int_constant_zero(tn->tn_left))) { 2935 /* expression has null effect */ 2936 warning(129); 2937 } 2938 } 2939 2940 /* 2941 * Check the types for specific operators and type combinations. 2942 * 2943 * At this point, the operands already conform to the type requirements of 2944 * the operator, such as being integer, floating or scalar. 2945 */ 2946 static bool 2947 typeok_op(op_t op, const mod_t *mp, int arg, 2948 const tnode_t *ln, const type_t *ltp, tspec_t lt, 2949 const tnode_t *rn, const type_t *rtp, tspec_t rt) 2950 { 2951 switch (op) { 2952 case ARROW: 2953 return typeok_arrow(lt); 2954 case POINT: 2955 return typeok_point(ln, ltp, lt); 2956 case INCBEF: 2957 case DECBEF: 2958 case INCAFT: 2959 case DECAFT: 2960 return typeok_incdec(op, ln, ltp); 2961 case INDIR: 2962 return typeok_indir(ltp, lt); 2963 case ADDR: 2964 return typeok_address(mp, ln, ltp, lt); 2965 case PLUS: 2966 return typeok_plus(op, ltp, lt, rtp, rt); 2967 case MINUS: 2968 return typeok_minus(op, ltp, lt, rtp, rt); 2969 case SHL: 2970 typeok_shl(mp, lt, rt); 2971 goto shift; 2972 case SHR: 2973 typeok_shr(mp, ln, lt, rn, rt); 2974 shift: 2975 typeok_shift(ltp, lt, rn, rt); 2976 break; 2977 case LT: 2978 case LE: 2979 case GT: 2980 case GE: 2981 compare: 2982 return typeok_compare(op, ln, ltp, lt, rn, rtp, rt); 2983 case EQ: 2984 case NE: 2985 if (is_typeok_eq(ln, lt, rn, rt)) 2986 break; 2987 goto compare; 2988 case QUEST: 2989 return typeok_quest(lt, rn); 2990 case COLON: 2991 return typeok_colon(mp, ln, ltp, lt, rn, rtp, rt); 2992 case ASSIGN: 2993 case INIT: 2994 case FARG: 2995 case RETURN: 2996 if (!check_assign_types_compatible(op, arg, ln, rn)) 2997 return false; 2998 goto assign; 2999 case MULASS: 3000 case DIVASS: 3001 case MODASS: 3002 goto assign; 3003 case ADDASS: 3004 case SUBASS: 3005 if ((lt == PTR && !is_integer(rt)) || rt == PTR) { 3006 warn_incompatible_types(op, ltp, lt, rtp, rt); 3007 return false; 3008 } 3009 goto assign; 3010 case SHLASS: 3011 goto assign; 3012 case SHRASS: 3013 if (pflag && !is_uinteger(lt) && 3014 !(!allow_c90 && is_uinteger(rt))) { 3015 /* bitwise '%s' on signed value possibly nonportable */ 3016 warning(117, mp->m_name); 3017 } 3018 goto assign; 3019 case ANDASS: 3020 case XORASS: 3021 case ORASS: 3022 assign: 3023 return typeok_assign(op, ln, ltp, lt); 3024 case COMMA: 3025 if (!modtab[ln->tn_op].m_has_side_effect) 3026 check_null_effect(ln); 3027 break; 3028 default: 3029 break; 3030 } 3031 return true; 3032 } 3033 3034 /* Prints a warning if a strange operator is used on an enum type. */ 3035 static void 3036 check_bad_enum_operation(op_t op, const tnode_t *ln, const tnode_t *rn) 3037 { 3038 3039 if (!eflag) 3040 return; 3041 3042 /* 3043 * Enum as offset to a pointer is an exception (otherwise enums 3044 * could not be used as array indices). 3045 */ 3046 if (op == PLUS && 3047 ((ln->tn_type->t_is_enum && rn->tn_type->t_tspec == PTR) || 3048 (rn->tn_type->t_is_enum && ln->tn_type->t_tspec == PTR))) { 3049 return; 3050 } 3051 3052 /* dubious operation on enum, op '%s' */ 3053 warning(241, op_name(op)); 3054 } 3055 3056 /* 3057 * Prints a warning if an operator is applied to two different enum types. 3058 */ 3059 static void 3060 check_enum_type_mismatch(op_t op, int arg, const tnode_t *ln, const tnode_t *rn) 3061 { 3062 const mod_t *mp = &modtab[op]; 3063 3064 if (ln->tn_type->t_enum != rn->tn_type->t_enum) { 3065 switch (op) { 3066 case INIT: 3067 /* enum type mismatch between '%s' and '%s' in ... */ 3068 warning(210, 3069 type_name(ln->tn_type), type_name(rn->tn_type)); 3070 break; 3071 case FARG: 3072 /* function expects '%s', passing '%s' for arg #%d */ 3073 warning(156, 3074 type_name(ln->tn_type), type_name(rn->tn_type), 3075 arg); 3076 break; 3077 case RETURN: 3078 /* function has return type '%s' but returns '%s' */ 3079 warning(211, 3080 type_name(ln->tn_type), type_name(rn->tn_type)); 3081 break; 3082 default: 3083 /* enum type mismatch: '%s' '%s' '%s' */ 3084 warning(130, type_name(ln->tn_type), mp->m_name, 3085 type_name(rn->tn_type)); 3086 break; 3087 } 3088 } else if (Pflag && mp->m_comparison && op != EQ && op != NE) { 3089 if (eflag) 3090 /* dubious comparison of enums, op '%s' */ 3091 warning(243, mp->m_name); 3092 } 3093 } 3094 3095 /* Prints a warning if the operands mix between enum and integer. */ 3096 static void 3097 check_enum_int_mismatch(op_t op, int arg, const tnode_t *ln, const tnode_t *rn) 3098 { 3099 3100 if (!eflag) 3101 return; 3102 3103 switch (op) { 3104 case INIT: 3105 /* 3106 * Initialization with 0 is allowed. Otherwise, all implicit 3107 * initializations would need to be warned upon as well. 3108 */ 3109 if (!rn->tn_type->t_is_enum && rn->tn_op == CON && 3110 is_integer(rn->tn_type->t_tspec) && 3111 rn->tn_val->v_quad == 0) { 3112 return; 3113 } 3114 /* initialization of '%s' with '%s' */ 3115 warning(277, type_name(ln->tn_type), type_name(rn->tn_type)); 3116 break; 3117 case FARG: 3118 /* combination of '%s' and '%s', arg #%d */ 3119 warning(278, 3120 type_name(ln->tn_type), type_name(rn->tn_type), arg); 3121 break; 3122 case RETURN: 3123 /* combination of '%s' and '%s' in return */ 3124 warning(279, type_name(ln->tn_type), type_name(rn->tn_type)); 3125 break; 3126 default: 3127 /* combination of '%s' and '%s', op '%s' */ 3128 warning(242, type_name(ln->tn_type), type_name(rn->tn_type), 3129 op_name(op)); 3130 break; 3131 } 3132 } 3133 3134 static void 3135 typeok_enum(op_t op, const mod_t *mp, int arg, 3136 const tnode_t *ln, const type_t *ltp, 3137 const tnode_t *rn, const type_t *rtp) 3138 { 3139 if (mp->m_bad_on_enum && 3140 (ltp->t_is_enum || (mp->m_binary && rtp->t_is_enum))) { 3141 check_bad_enum_operation(op, ln, rn); 3142 } else if (mp->m_valid_on_enum && 3143 (ltp->t_is_enum && rtp != NULL && rtp->t_is_enum)) { 3144 check_enum_type_mismatch(op, arg, ln, rn); 3145 } else if (mp->m_valid_on_enum && 3146 (ltp->t_is_enum || (rtp != NULL && rtp->t_is_enum))) { 3147 check_enum_int_mismatch(op, arg, ln, rn); 3148 } 3149 } 3150 3151 /* Perform most type checks. Return whether the types are ok. */ 3152 bool 3153 typeok(op_t op, int arg, const tnode_t *ln, const tnode_t *rn) 3154 { 3155 tspec_t lt, rt; 3156 type_t *ltp, *rtp; 3157 3158 const mod_t *mp = &modtab[op]; 3159 3160 lint_assert((ltp = ln->tn_type) != NULL); 3161 lt = ltp->t_tspec; 3162 3163 if (mp->m_binary) { 3164 lint_assert((rtp = rn->tn_type) != NULL); 3165 rt = rtp->t_tspec; 3166 } else { 3167 rtp = NULL; 3168 rt = NOTSPEC; 3169 } 3170 3171 if (Tflag && !typeok_scalar_strict_bool(op, mp, arg, ln, rn)) 3172 return false; 3173 if (!typeok_scalar(op, mp, ltp, lt, rtp, rt)) 3174 return false; 3175 3176 if (!typeok_op(op, mp, arg, ln, ltp, lt, rn, rtp, rt)) 3177 return false; 3178 3179 typeok_enum(op, mp, arg, ln, ltp, rn, rtp); 3180 return true; 3181 } 3182 3183 /* In traditional C, keep unsigned and promote FLOAT to DOUBLE. */ 3184 static tspec_t 3185 promote_trad(tspec_t t) 3186 { 3187 3188 if (t == UCHAR || t == USHORT) 3189 return UINT; 3190 if (t == CHAR || t == SCHAR || t == SHORT) 3191 return INT; 3192 if (t == FLOAT) 3193 return DOUBLE; 3194 if (t == ENUM) 3195 return INT; 3196 return t; 3197 } 3198 3199 /* 3200 * C99 6.3.1.1p2 requires for types with lower rank than int that "If an int 3201 * can represent all the values of the original type, the value is converted 3202 * to an int; otherwise it is converted to an unsigned int", and that "All 3203 * other types are unchanged by the integer promotions". 3204 */ 3205 static tspec_t 3206 promote_c90(const tnode_t *tn, tspec_t t, bool farg) 3207 { 3208 if (tn->tn_type->t_bitfield) { 3209 unsigned int len = tn->tn_type->t_flen; 3210 if (len < size_in_bits(INT)) 3211 return INT; 3212 if (len == size_in_bits(INT)) 3213 return is_uinteger(t) ? UINT : INT; 3214 return t; 3215 } 3216 3217 if (t == CHAR || t == SCHAR) 3218 return INT; 3219 if (t == UCHAR) 3220 return size_in_bits(CHAR) < size_in_bits(INT) ? INT : UINT; 3221 if (t == SHORT) 3222 return INT; 3223 if (t == USHORT) 3224 return size_in_bits(SHORT) < size_in_bits(INT) ? INT : UINT; 3225 if (t == ENUM) 3226 return INT; 3227 if (farg && t == FLOAT) 3228 return DOUBLE; 3229 return t; 3230 } 3231 3232 /* 3233 * Performs the "integer promotions" (C99 6.3.1.1p2), which convert small 3234 * integer types to either int or unsigned int. 3235 * 3236 * If allow_c90 is unset or the operand is a function argument with no type 3237 * information (no prototype or variable # of args), converts float to double. 3238 */ 3239 tnode_t * 3240 promote(op_t op, bool farg, tnode_t *tn) 3241 { 3242 3243 tspec_t ot = tn->tn_type->t_tspec; 3244 if (!is_arithmetic(ot)) 3245 return tn; 3246 3247 tspec_t nt = allow_c90 ? promote_c90(tn, ot, farg) : promote_trad(ot); 3248 if (nt == ot) 3249 return tn; 3250 3251 type_t *ntp = expr_dup_type(tn->tn_type); 3252 ntp->t_tspec = nt; 3253 /* 3254 * Keep t_is_enum even though t_tspec gets converted from 3255 * ENUM to INT, so we are later able to check compatibility 3256 * of enum types. 3257 */ 3258 return convert(op, 0, ntp, tn); 3259 } 3260 3261 static void 3262 convert_integer_from_floating(op_t op, const type_t *tp, const tnode_t *tn) 3263 { 3264 3265 if (op == CVT) 3266 /* cast from floating point '%s' to integer '%s' */ 3267 query_message(2, type_name(tn->tn_type), type_name(tp)); 3268 else 3269 /* implicit conversion from floating point '%s' to ... */ 3270 query_message(1, type_name(tn->tn_type), type_name(tp)); 3271 } 3272 3273 static bool 3274 should_warn_about_prototype_conversion(tspec_t nt, 3275 tspec_t ot, const tnode_t *ptn) 3276 { 3277 3278 if (nt == ot) 3279 return false; 3280 3281 if (nt == ENUM && ot == INT) 3282 return false; 3283 3284 if (is_floating(nt) != is_floating(ot) || 3285 portable_size_in_bits(nt) != portable_size_in_bits(ot)) { 3286 /* representation and/or width change */ 3287 if (!is_integer(ot)) 3288 return true; 3289 /* 3290 * XXX: Investigate whether this rule makes sense; see 3291 * tests/usr.bin/xlint/lint1/platform_long.c. 3292 */ 3293 return portable_size_in_bits(ot) > portable_size_in_bits(INT); 3294 } 3295 3296 if (!hflag) 3297 return false; 3298 3299 /* 3300 * If the types differ only in sign and the argument has the same 3301 * representation in both types, print no warning. 3302 */ 3303 if (ptn->tn_op == CON && is_integer(nt) && 3304 signed_type(nt) == signed_type(ot) && 3305 !msb(ptn->tn_val->v_quad, ot)) 3306 return false; 3307 3308 return true; 3309 } 3310 3311 /* 3312 * Warn if a prototype causes a type conversion that is different from what 3313 * would happen to the same argument in the absence of a prototype. This 3314 * check is intended for code that needs to stay compatible with pre-C90 C. 3315 * 3316 * Errors/warnings about illegal type combinations are already printed 3317 * in check_assign_types_compatible(). 3318 */ 3319 static void 3320 check_prototype_conversion(int arg, tspec_t nt, tspec_t ot, type_t *tp, 3321 tnode_t *tn) 3322 { 3323 3324 if (!is_arithmetic(nt) || !is_arithmetic(ot)) 3325 return; 3326 3327 /* 3328 * If the type of the formal parameter is char/short, a warning 3329 * would be useless, because functions declared the old style 3330 * can't expect char/short arguments. 3331 */ 3332 if (nt == CHAR || nt == SCHAR || nt == UCHAR || 3333 nt == SHORT || nt == USHORT) 3334 return; 3335 3336 /* apply the default promotion */ 3337 tnode_t *ptn = promote(NOOP, true, tn); 3338 ot = ptn->tn_type->t_tspec; 3339 3340 if (should_warn_about_prototype_conversion(nt, ot, ptn)) { 3341 /* argument #%d is converted from '%s' to '%s' ... */ 3342 warning(259, arg, type_name(tn->tn_type), type_name(tp)); 3343 } 3344 } 3345 3346 /* 3347 * When converting a large integer type to a small integer type, in some 3348 * cases the value of the actual expression is further restricted than the 3349 * type bounds, such as in (expr & 0xFF) or (expr % 100) or (expr >> 24). 3350 */ 3351 static bool 3352 can_represent(const type_t *tp, const tnode_t *tn) 3353 { 3354 3355 debug_step("%s: type '%s'", __func__, type_name(tp)); 3356 debug_node(tn); 3357 3358 uint64_t nmask = value_bits(width_in_bits(tp)); 3359 if (!is_uinteger(tp->t_tspec)) 3360 nmask >>= 1; 3361 3362 integer_constraints c = ic_expr(tn); 3363 if ((~c.bclr & ~nmask) == 0) 3364 return true; 3365 3366 return false; 3367 } 3368 3369 static void 3370 convert_integer_from_integer(op_t op, int arg, tspec_t nt, tspec_t ot, 3371 type_t *tp, tnode_t *tn) 3372 { 3373 3374 if (tn->tn_op == CON) 3375 return; 3376 3377 if (op == CVT) 3378 return; 3379 3380 if (Pflag && pflag && aflag > 0 && 3381 portable_size_in_bits(nt) > portable_size_in_bits(ot) && 3382 is_uinteger(nt) != is_uinteger(ot)) { 3383 if (op == FARG) { 3384 /* conversion to '%s' may sign-extend ... */ 3385 warning(297, type_name(tp), arg); 3386 } else { 3387 /* conversion to '%s' may sign-extend ... */ 3388 warning(131, type_name(tp)); 3389 } 3390 } 3391 3392 if (Pflag && portable_size_in_bits(nt) > portable_size_in_bits(ot) && 3393 (tn->tn_op == PLUS || tn->tn_op == MINUS || tn->tn_op == MULT || 3394 tn->tn_op == SHL)) { 3395 /* suggest cast from '%s' to '%s' on op '%s' to ... */ 3396 warning(324, type_name(gettyp(ot)), type_name(tp), 3397 op_name(tn->tn_op)); 3398 } 3399 3400 if (aflag > 0 && 3401 portable_size_in_bits(nt) < portable_size_in_bits(ot) && 3402 (ot == LONG || ot == ULONG || ot == QUAD || ot == UQUAD || 3403 aflag > 1) && 3404 !can_represent(tp, tn)) { 3405 if (op == FARG) { 3406 /* conversion from '%s' to '%s' may lose ... */ 3407 warning(298, 3408 type_name(tn->tn_type), type_name(tp), arg); 3409 } else { 3410 /* conversion from '%s' to '%s' may lose accuracy */ 3411 warning(132, 3412 type_name(tn->tn_type), type_name(tp)); 3413 } 3414 } 3415 3416 if (is_uinteger(nt) != is_uinteger(ot)) 3417 /* implicit conversion changes sign from '%s' to '%s' */ 3418 query_message(3, type_name(tn->tn_type), type_name(tp)); 3419 } 3420 3421 static void 3422 convert_integer_from_pointer(op_t op, tspec_t nt, type_t *tp, tnode_t *tn) 3423 { 3424 3425 if (tn->tn_op == CON) 3426 return; 3427 if (op != CVT) 3428 return; /* We already got an error. */ 3429 if (portable_size_in_bits(nt) >= portable_size_in_bits(PTR)) 3430 return; 3431 3432 if (pflag && size_in_bits(nt) >= size_in_bits(PTR)) { 3433 /* conversion of pointer to '%s' may lose bits */ 3434 warning(134, type_name(tp)); 3435 } else { 3436 /* conversion of pointer to '%s' loses bits */ 3437 warning(133, type_name(tp)); 3438 } 3439 } 3440 3441 static bool 3442 struct_starts_with(const type_t *struct_tp, const type_t *member_tp) 3443 { 3444 3445 return struct_tp->t_sou->sou_first_member != NULL && 3446 types_compatible(struct_tp->t_sou->sou_first_member->s_type, 3447 member_tp, true, false, NULL); 3448 } 3449 3450 static bool 3451 is_byte_array(const type_t *tp) 3452 { 3453 3454 return tp->t_tspec == ARRAY && 3455 (tp->t_subt->t_tspec == CHAR || tp->t_subt->t_tspec == UCHAR); 3456 } 3457 3458 static bool 3459 union_contains(const type_t *utp, const type_t *mtp) 3460 { 3461 for (const sym_t *mem = utp->t_sou->sou_first_member; 3462 mem != NULL; mem = mem->s_next) { 3463 if (types_compatible(mem->s_type, mtp, true, false, NULL)) 3464 return true; 3465 } 3466 return false; 3467 } 3468 3469 static bool 3470 should_warn_about_pointer_cast(const type_t *nstp, tspec_t nst, 3471 const type_t *ostp, tspec_t ost) 3472 { 3473 3474 while (nst == ARRAY) 3475 nstp = nstp->t_subt, nst = nstp->t_tspec; 3476 while (ost == ARRAY) 3477 ostp = ostp->t_subt, ost = ostp->t_tspec; 3478 3479 if (nst == STRUCT && ost == STRUCT && 3480 (struct_starts_with(nstp, ostp) || 3481 struct_starts_with(ostp, nstp))) 3482 return false; 3483 3484 if (is_incomplete(nstp) || is_incomplete(ostp)) 3485 return false; 3486 3487 if (nst == CHAR || nst == UCHAR) 3488 return false; /* for the sake of traditional C code */ 3489 if (ost == CHAR || ost == UCHAR) 3490 return false; /* for the sake of traditional C code */ 3491 3492 /* Allow cast between pointers to sockaddr variants. */ 3493 if (nst == STRUCT && ost == STRUCT) { 3494 debug_type(nstp); 3495 debug_type(ostp); 3496 const sym_t *nmem = nstp->t_sou->sou_first_member; 3497 const sym_t *omem = ostp->t_sou->sou_first_member; 3498 while (nmem != NULL && omem != NULL && 3499 types_compatible(nmem->s_type, omem->s_type, 3500 true, false, NULL)) 3501 nmem = nmem->s_next, omem = omem->s_next; 3502 if (nmem != NULL && is_byte_array(nmem->s_type)) 3503 return false; 3504 if (omem != NULL && is_byte_array(omem->s_type)) 3505 return false; 3506 if (nmem == NULL && omem == NULL) 3507 return false; 3508 } 3509 3510 if (nst == UNION || ost == UNION) { 3511 const type_t *union_tp = nst == UNION ? nstp : ostp; 3512 const type_t *other_tp = nst == UNION ? ostp : nstp; 3513 if (union_contains(union_tp, other_tp)) 3514 return false; 3515 } 3516 3517 if (is_struct_or_union(nst) && nstp->t_sou != ostp->t_sou) 3518 return true; 3519 3520 return portable_size_in_bits(nst) != portable_size_in_bits(ost); 3521 } 3522 3523 static void 3524 convert_pointer_from_pointer(type_t *ntp, tnode_t *tn) 3525 { 3526 const type_t *nstp = ntp->t_subt; 3527 const type_t *otp = tn->tn_type; 3528 const type_t *ostp = otp->t_subt; 3529 tspec_t nst = nstp->t_tspec; 3530 tspec_t 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 const char *nts, *ots; 3536 /* null pointers are already handled in convert() */ 3537 *(nst == FUNC ? &nts : &ots) = "function pointer"; 3538 *(nst == VOID ? &nts : &ots) = "'void *'"; 3539 /* ANSI C forbids conversion of %s to %s */ 3540 warning(303, ots, nts); 3541 } 3542 return; 3543 } 3544 if (nst == FUNC && ost == FUNC) 3545 return; 3546 if (nst == FUNC || ost == FUNC) { 3547 /* converting '%s' to '%s' is questionable */ 3548 warning(229, type_name(otp), type_name(ntp)); 3549 return; 3550 } 3551 3552 if (hflag && alignment_in_bits(nstp) > alignment_in_bits(ostp) && 3553 ost != CHAR && ost != UCHAR && 3554 !is_incomplete(ostp) && 3555 !(nst == UNION && union_contains(nstp, ostp))) { 3556 /* converting '%s' to '%s' increases alignment ... */ 3557 warning(135, type_name(otp), type_name(ntp), 3558 alignment_in_bits(ostp) / CHAR_SIZE, 3559 alignment_in_bits(nstp) / CHAR_SIZE); 3560 } 3561 3562 if (cflag && should_warn_about_pointer_cast(nstp, nst, ostp, ost)) { 3563 /* pointer cast from '%s' to '%s' may be troublesome */ 3564 warning(247, type_name(otp), type_name(ntp)); 3565 } 3566 } 3567 3568 /* 3569 * Insert a conversion operator, which converts the type of the node 3570 * to another given type. 3571 * 3572 * Possible values for 'op': 3573 * CVT a cast-expression 3574 * binary integer promotion for one of the operands, or a usual 3575 * arithmetic conversion 3576 * binary plain or compound assignments to bit-fields 3577 * FARG 'arg' is the number of the argument (used for warnings) 3578 * NOOP several other implicit conversions 3579 * ... 3580 */ 3581 tnode_t * 3582 convert(op_t op, int arg, type_t *tp, tnode_t *tn) 3583 { 3584 tspec_t nt = tp->t_tspec; 3585 tspec_t 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 tnode_t *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 /* Already got 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 || nt == FCOMPLEX) { 3693 nv->v_ldbl = (float)v->v_ldbl; 3694 } else if (nt == DOUBLE || nt == DCOMPLEX) { 3695 nv->v_ldbl = (double)v->v_ldbl; 3696 } else if (nt == LDOUBLE || nt == LCOMPLEX) { 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 of unsigned types or all 3782 * truncated bits plus the msb of the target for signed types are considered 3783 * to be significant bits. Loss of significant bits means that at least one 3784 * of the bits was set in an unsigned type or that at least one but not all 3785 * of the bits was set in a signed type. Loss of significant bits means that 3786 * it is not possible, also not with necessary casts, to convert back to the 3787 * original type. A example for a necessary cast is: 3788 * char c; int i; c = 128; 3789 * i = c; ** yields -128 ** 3790 * i = (unsigned char)c; ** yields 128 ** 3791 */ 3792 static void 3793 convert_constant_check_range_truncated(op_t op, int arg, const type_t *tp, 3794 tspec_t ot) 3795 { 3796 if (op == ASSIGN && tp->t_bitfield) { 3797 /* precision lost in bit-field assignment */ 3798 warning(166); 3799 } else if (op == ASSIGN) { 3800 /* constant truncated by assignment */ 3801 warning(165); 3802 } else if (op == INIT && tp->t_bitfield) { 3803 /* bit-field initializer does not fit */ 3804 warning(180); 3805 } else if (op == INIT) { 3806 /* initializer does not fit */ 3807 warning(178); 3808 } else if (op == CASE) { 3809 /* case label affected by conversion */ 3810 warning(196); 3811 } else if (op == FARG) { 3812 /* conversion of '%s' to '%s' is out of range, arg #%d */ 3813 warning(295, 3814 type_name(gettyp(ot)), type_name(tp), arg); 3815 } else { 3816 /* conversion of '%s' to '%s' is out of range */ 3817 warning(119, 3818 type_name(gettyp(ot)), type_name(tp)); 3819 } 3820 } 3821 3822 static void 3823 convert_constant_check_range_loss(op_t op, int arg, const type_t *tp, 3824 tspec_t ot) 3825 { 3826 if (op == ASSIGN && tp->t_bitfield) { 3827 /* precision lost in bit-field assignment */ 3828 warning(166); 3829 } else if (op == INIT && tp->t_bitfield) { 3830 /* bit-field initializer out of range */ 3831 warning(11); 3832 } else if (op == CASE) { 3833 /* case label affected by conversion */ 3834 warning(196); 3835 } else if (op == FARG) { 3836 /* conversion of '%s' to '%s' is out of range, arg #%d */ 3837 warning(295, type_name(gettyp(ot)), type_name(tp), arg); 3838 } else { 3839 /* conversion of '%s' to '%s' is out of range */ 3840 warning(119, type_name(gettyp(ot)), type_name(tp)); 3841 } 3842 } 3843 3844 static void 3845 convert_constant_check_range(tspec_t ot, const type_t *tp, tspec_t nt, 3846 op_t op, int arg, const val_t *v, val_t *nv) 3847 { 3848 unsigned int obitsz, nbitsz; 3849 uint64_t xmask, xmsk1; 3850 3851 obitsz = size_in_bits(ot); 3852 nbitsz = tp->t_bitfield ? tp->t_flen : size_in_bits(nt); 3853 xmask = value_bits(nbitsz) ^ value_bits(obitsz); 3854 xmsk1 = value_bits(nbitsz) ^ value_bits(obitsz - 1); 3855 /* 3856 * For bitwise operations we are not interested in the arithmetic 3857 * value, but in the bits itself. 3858 */ 3859 if (op == ORASS || op == BITOR || op == BITXOR) { 3860 convert_constant_check_range_bitor( 3861 nbitsz, obitsz, v, xmask, op); 3862 } else if (op == ANDASS || op == BITAND) { 3863 convert_constant_check_range_bitand( 3864 nbitsz, obitsz, xmask, nv, ot, v, tp, op); 3865 } else if ((nt != PTR && is_uinteger(nt)) && 3866 (ot != PTR && !is_uinteger(ot)) && 3867 v->v_quad < 0) { 3868 convert_constant_check_range_signed(op, arg); 3869 } else if (nv->v_quad != v->v_quad && nbitsz <= obitsz && 3870 (v->v_quad & xmask) != 0 && 3871 (is_uinteger(ot) || (v->v_quad & xmsk1) != xmsk1)) { 3872 convert_constant_check_range_truncated(op, arg, tp, ot); 3873 } else if (nv->v_quad != v->v_quad) { 3874 convert_constant_check_range_loss(op, arg, tp, ot); 3875 } 3876 } 3877 3878 /* 3879 * Converts a typed constant to a constant of another type. 3880 * 3881 * op operator which requires conversion 3882 * arg if op is FARG, # of argument 3883 * tp type to which to convert the constant 3884 * nv new constant 3885 * v old constant 3886 */ 3887 void 3888 convert_constant(op_t op, int arg, const type_t *tp, val_t *nv, val_t *v) 3889 { 3890 /* 3891 * TODO: make 'v' const; the name of this function does not suggest 3892 * that it modifies 'v'. 3893 */ 3894 tspec_t ot = v->v_tspec; 3895 tspec_t nt = nv->v_tspec = tp->t_tspec; 3896 bool range_check = false; 3897 3898 if (nt == BOOL) { /* C99 6.3.1.2 */ 3899 nv->v_unsigned_since_c90 = false; 3900 nv->v_quad = is_nonzero_val(v) ? 1 : 0; 3901 return; 3902 } 3903 3904 if (ot == FLOAT || ot == DOUBLE || ot == LDOUBLE) { 3905 convert_constant_floating(op, arg, ot, tp, nt, v, nv); 3906 } else if (!convert_constant_to_floating(nt, nv, ot, v)) { 3907 range_check = true; /* Check for lost precision. */ 3908 nv->v_quad = v->v_quad; 3909 } 3910 3911 if (allow_trad && allow_c90 && v->v_unsigned_since_c90 && 3912 (is_floating(nt) || ( 3913 (is_integer(nt) && !is_uinteger(nt) && 3914 portable_size_in_bits(nt) > portable_size_in_bits(ot))))) { 3915 /* ANSI C treats constant as unsigned */ 3916 warning(157); 3917 v->v_unsigned_since_c90 = false; 3918 } 3919 3920 if (is_integer(nt)) { 3921 nv->v_quad = convert_integer(nv->v_quad, nt, 3922 tp->t_bitfield ? tp->t_flen : size_in_bits(nt)); 3923 } 3924 3925 if (range_check && op != CVT) 3926 convert_constant_check_range(ot, tp, nt, op, arg, v, nv); 3927 } 3928 3929 /* 3930 * Create a constant node for sizeof. 3931 */ 3932 tnode_t * 3933 build_sizeof(const type_t *tp) 3934 { 3935 unsigned int size_in_bytes = type_size_in_bits(tp) / CHAR_SIZE; 3936 tnode_t *tn = build_integer_constant(SIZEOF_TSPEC, size_in_bytes); 3937 tn->tn_system_dependent = true; 3938 debug_step("build_sizeof '%s' = %u", type_name(tp), size_in_bytes); 3939 return tn; 3940 } 3941 3942 /* 3943 * Create a constant node for offsetof. 3944 */ 3945 /* ARGSUSED */ /* FIXME: See implementation comments. */ 3946 tnode_t * 3947 build_offsetof(const type_t *tp, const sym_t *sym) 3948 { 3949 unsigned int offset_in_bytes; 3950 tnode_t *tn; 3951 3952 if (!is_struct_or_union(tp->t_tspec)) 3953 /* unacceptable operand of '%s' */ 3954 error(111, "offsetof"); 3955 3956 /* FIXME: Don't wrongly use the size of the whole type, use sym. */ 3957 offset_in_bytes = type_size_in_bits(tp) / CHAR_SIZE; 3958 tn = build_integer_constant(SIZEOF_TSPEC, offset_in_bytes); 3959 tn->tn_system_dependent = true; 3960 return tn; 3961 } 3962 3963 unsigned int 3964 type_size_in_bits(const type_t *tp) 3965 { 3966 unsigned int elsz; 3967 3968 unsigned int elem = 1; 3969 bool flex = false; 3970 lint_assert(tp != NULL); 3971 while (tp->t_tspec == ARRAY) { 3972 flex = true; /* allow c99 flex arrays [] [0] */ 3973 elem *= tp->t_dim; 3974 tp = tp->t_subt; 3975 } 3976 if (elem == 0) { 3977 if (!flex) { 3978 /* cannot take size/alignment of incomplete type */ 3979 error(143); 3980 elem = 1; 3981 } 3982 } 3983 switch (tp->t_tspec) { 3984 case FUNC: 3985 /* cannot take size/alignment of function type '%s' */ 3986 error(144, type_name(tp)); 3987 elsz = 1; 3988 break; 3989 case STRUCT: 3990 case UNION: 3991 if (is_incomplete(tp)) { 3992 /* cannot take size/alignment of incomplete type */ 3993 error(143); 3994 elsz = 1; 3995 } else { 3996 elsz = tp->t_sou->sou_size_in_bits; 3997 } 3998 break; 3999 case ENUM: 4000 if (is_incomplete(tp)) { 4001 /* cannot take size/alignment of incomplete type */ 4002 warning(143); 4003 } 4004 /* FALLTHROUGH */ 4005 default: 4006 if (tp->t_bitfield) { 4007 /* cannot take size/alignment of bit-field */ 4008 error(145); 4009 } 4010 if (tp->t_tspec == VOID) { 4011 /* cannot take size/alignment of void */ 4012 error(146); 4013 elsz = 1; 4014 } else { 4015 elsz = size_in_bits(tp->t_tspec); 4016 lint_assert(elsz > 0); 4017 } 4018 break; 4019 } 4020 4021 return elem * elsz; 4022 } 4023 4024 tnode_t * 4025 build_alignof(const type_t *tp) 4026 { 4027 switch (tp->t_tspec) { 4028 case ARRAY: 4029 break; 4030 4031 case FUNC: 4032 /* cannot take size/alignment of function type '%s' */ 4033 error(144, type_name(tp)); 4034 return 0; 4035 4036 case STRUCT: 4037 case UNION: 4038 if (is_incomplete(tp)) { 4039 /* cannot take size/alignment of incomplete type */ 4040 error(143); 4041 return 0; 4042 } 4043 break; 4044 case ENUM: 4045 break; 4046 default: 4047 if (tp->t_bitfield) { 4048 /* cannot take size/alignment of bit-field */ 4049 error(145); 4050 return 0; 4051 } 4052 if (tp->t_tspec == VOID) { 4053 /* cannot take size/alignment of void */ 4054 error(146); 4055 return 0; 4056 } 4057 break; 4058 } 4059 4060 return build_integer_constant(SIZEOF_TSPEC, 4061 (int64_t)alignment_in_bits(tp) / CHAR_SIZE); 4062 } 4063 4064 static tnode_t * 4065 cast_to_union(tnode_t *otn, type_t *ntp) 4066 { 4067 4068 if (!allow_gcc) { 4069 /* union cast is a GCC extension */ 4070 error(328); 4071 return NULL; 4072 } 4073 4074 for (const sym_t *m = ntp->t_sou->sou_first_member; 4075 m != NULL; m = m->s_next) { 4076 if (types_compatible(m->s_type, otn->tn_type, 4077 false, false, NULL)) { 4078 tnode_t *ntn = expr_alloc_tnode(); 4079 ntn->tn_op = CVT; 4080 ntn->tn_type = ntp; 4081 ntn->tn_cast = true; 4082 ntn->tn_left = otn; 4083 ntn->tn_right = NULL; 4084 return ntn; 4085 } 4086 } 4087 4088 /* type '%s' is not a member of '%s' */ 4089 error(329, type_name(otn->tn_type), type_name(ntp)); 4090 return NULL; 4091 } 4092 4093 /* 4094 * Type casts. 4095 */ 4096 tnode_t * 4097 cast(tnode_t *tn, type_t *tp) 4098 { 4099 tspec_t nt, ot; 4100 4101 if (tn == NULL) 4102 return NULL; 4103 4104 tn = cconv(tn); 4105 4106 lint_assert(tp != NULL); 4107 nt = tp->t_tspec; 4108 ot = tn->tn_type->t_tspec; 4109 4110 if (nt == VOID) { 4111 /* 4112 * C90 6.3.4, C99 6.5.4p2 and C11 6.5.4p2 allow any type to 4113 * be cast to void. The only other allowed casts are from a 4114 * scalar type to a scalar type. 4115 */ 4116 } else if (nt == UNION) { 4117 return cast_to_union(tn, tp); 4118 } else if (nt == STRUCT || nt == ARRAY || nt == FUNC) { 4119 /* Casting to a struct is an undocumented GCC extension. */ 4120 if (!(allow_gcc && nt == STRUCT)) 4121 goto invalid_cast; 4122 } else if (is_struct_or_union(ot)) { 4123 goto invalid_cast; 4124 } else if (ot == VOID) { 4125 /* improper cast of void expression */ 4126 error(148); 4127 return NULL; 4128 } else if (is_integer(nt) && is_scalar(ot)) { 4129 /* ok */ 4130 } else if (is_floating(nt) && is_arithmetic(ot)) { 4131 /* ok */ 4132 } else if (nt == PTR && is_integer(ot)) { 4133 /* ok */ 4134 } else if (nt == PTR && ot == PTR) { 4135 if (!tp->t_subt->t_const && tn->tn_type->t_subt->t_const) { 4136 if (hflag) 4137 /* cast discards 'const' from type '%s' */ 4138 warning(275, type_name(tn->tn_type)); 4139 } 4140 } else 4141 goto invalid_cast; 4142 4143 if (any_query_enabled && types_compatible(tp, tn->tn_type, 4144 false, false, NULL)) { 4145 /* no-op cast from '%s' to '%s' */ 4146 query_message(6, type_name(tn->tn_type), type_name(tp)); 4147 } 4148 4149 tn = convert(CVT, 0, tp, tn); 4150 tn->tn_cast = true; 4151 4152 return tn; 4153 4154 invalid_cast: 4155 /* invalid cast from '%s' to '%s' */ 4156 error(147, type_name(tn->tn_type), type_name(tp)); 4157 return NULL; 4158 } 4159 4160 /* 4161 * Create the node for a function argument. 4162 * All necessary conversions and type checks are done in 4163 * build_function_call because build_function_argument has no 4164 * information about expected argument types. 4165 */ 4166 tnode_t * 4167 build_function_argument(tnode_t *args, tnode_t *arg) 4168 { 4169 /* 4170 * If there was a serious error in the expression for the argument, 4171 * create a dummy argument so the positions of the remaining arguments 4172 * will not change. 4173 */ 4174 if (arg == NULL) 4175 arg = build_integer_constant(INT, 0); 4176 4177 return new_tnode(PUSH, arg->tn_sys, arg->tn_type, arg, args); 4178 } 4179 4180 /* 4181 * Compare the type of an argument with the corresponding type of a 4182 * prototype parameter. If it is a valid combination, but both types 4183 * are not the same, insert a conversion to convert the argument into 4184 * the type of the parameter. 4185 */ 4186 static tnode_t * 4187 check_prototype_argument( 4188 int n, /* pos of arg */ 4189 type_t *tp, /* expected type (from prototype) */ 4190 tnode_t *tn) /* argument */ 4191 { 4192 tnode_t *ln = xcalloc(1, sizeof(*ln)); 4193 ln->tn_type = expr_unqualified_type(tp); 4194 ln->tn_lvalue = true; 4195 if (typeok(FARG, n, ln, tn)) { 4196 bool dowarn; 4197 if (!types_compatible(tp, tn->tn_type, 4198 true, false, (dowarn = false, &dowarn)) || dowarn) 4199 tn = convert(FARG, n, tp, tn); 4200 } 4201 free(ln); 4202 return tn; 4203 } 4204 4205 /* 4206 * Check types of all function arguments and insert conversions, 4207 * if necessary. 4208 */ 4209 static tnode_t * 4210 check_function_arguments(type_t *ftp, tnode_t *args) 4211 { 4212 tnode_t *arg; 4213 sym_t *asym; 4214 tspec_t at; 4215 int narg, npar, n, i; 4216 4217 /* get # of args in the prototype */ 4218 npar = 0; 4219 for (asym = ftp->t_args; asym != NULL; asym = asym->s_next) 4220 npar++; 4221 4222 /* get # of args in function call */ 4223 narg = 0; 4224 for (arg = args; arg != NULL; arg = arg->tn_right) 4225 narg++; 4226 4227 asym = ftp->t_args; 4228 if (ftp->t_proto && npar != narg && !(ftp->t_vararg && npar < narg)) { 4229 /* argument mismatch: %d %s passed, %d expected */ 4230 error(150, narg, narg > 1 ? "arguments" : "argument", npar); 4231 asym = NULL; 4232 } 4233 4234 for (n = 1; n <= narg; n++) { 4235 4236 /* 4237 * The rightmost argument is at the top of the argument 4238 * subtree. 4239 */ 4240 for (i = narg, arg = args; i > n; i--, arg = arg->tn_right) 4241 continue; 4242 4243 /* some things which are always not allowed */ 4244 if ((at = arg->tn_left->tn_type->t_tspec) == VOID) { 4245 /* void expressions may not be arguments, arg #%d */ 4246 error(151, n); 4247 return NULL; 4248 } else if (is_struct_or_union(at) && 4249 is_incomplete(arg->tn_left->tn_type)) { 4250 /* argument cannot have unknown size, arg #%d */ 4251 error(152, n); 4252 return NULL; 4253 } else if (is_integer(at) && 4254 arg->tn_left->tn_type->t_is_enum && 4255 is_incomplete(arg->tn_left->tn_type)) { 4256 /* argument cannot have unknown size, arg #%d */ 4257 warning(152, n); 4258 } 4259 4260 /* class conversions (arg in value context) */ 4261 arg->tn_left = cconv(arg->tn_left); 4262 4263 if (asym != NULL) { 4264 arg->tn_left = check_prototype_argument( 4265 n, asym->s_type, arg->tn_left); 4266 } else { 4267 arg->tn_left = promote(NOOP, true, arg->tn_left); 4268 } 4269 arg->tn_type = arg->tn_left->tn_type; 4270 4271 if (asym != NULL) 4272 asym = asym->s_next; 4273 } 4274 4275 return args; 4276 } 4277 4278 /* 4279 * Create the node for a function call. Also check types of 4280 * function arguments and insert conversions, if necessary. 4281 */ 4282 tnode_t * 4283 build_function_call(tnode_t *func, bool sys, tnode_t *args) 4284 { 4285 tnode_t *ntn; 4286 op_t fcop; 4287 4288 if (func == NULL) 4289 return NULL; 4290 4291 if (func->tn_op == NAME && func->tn_type->t_tspec == FUNC) { 4292 fcop = CALL; 4293 } else { 4294 fcop = ICALL; 4295 } 4296 4297 check_ctype_function_call(func, args); 4298 4299 /* 4300 * after cconv() func will always be a pointer to a function 4301 * if it is a valid function designator. 4302 */ 4303 func = cconv(func); 4304 4305 if (func->tn_type->t_tspec != PTR || 4306 func->tn_type->t_subt->t_tspec != FUNC) { 4307 /* cannot call '%s', must be a function */ 4308 error(149, type_name(func->tn_type)); 4309 return NULL; 4310 } 4311 4312 args = check_function_arguments(func->tn_type->t_subt, args); 4313 4314 ntn = new_tnode(fcop, sys, func->tn_type->t_subt->t_subt, func, args); 4315 4316 return ntn; 4317 } 4318 4319 /* 4320 * Return the value of an integral constant expression. 4321 * If the expression is not constant or its type is not an integer 4322 * type, an error message is printed. 4323 */ 4324 val_t * 4325 constant(tnode_t *tn, bool required) 4326 { 4327 4328 if (tn != NULL) 4329 tn = cconv(tn); 4330 if (tn != NULL) 4331 tn = promote(NOOP, false, tn); 4332 4333 val_t *v = xcalloc(1, sizeof(*v)); 4334 4335 if (tn == NULL) { 4336 lint_assert(nerr != 0); 4337 debug_step("constant node is null; returning 1 instead"); 4338 v->v_tspec = INT; 4339 v->v_quad = 1; 4340 return v; 4341 } 4342 4343 v->v_tspec = tn->tn_type->t_tspec; 4344 4345 if (tn->tn_op == CON) { 4346 lint_assert(tn->tn_type->t_tspec == tn->tn_val->v_tspec); 4347 if (is_integer(tn->tn_val->v_tspec)) { 4348 v->v_unsigned_since_c90 = 4349 tn->tn_val->v_unsigned_since_c90; 4350 v->v_quad = tn->tn_val->v_quad; 4351 return v; 4352 } 4353 v->v_quad = tn->tn_val->v_ldbl; 4354 } else { 4355 v->v_quad = 1; 4356 } 4357 4358 if (required) 4359 /* integral constant expression expected */ 4360 error(55); 4361 else 4362 /* variable array dimension is a C99/GCC extension */ 4363 c99ism(318); 4364 4365 if (!is_integer(v->v_tspec)) 4366 v->v_tspec = INT; 4367 4368 return v; 4369 } 4370 4371 static bool 4372 is_constcond_false(const tnode_t *tn, tspec_t t) 4373 { 4374 return (t == BOOL || t == INT) && 4375 tn->tn_op == CON && tn->tn_val->v_quad == 0; 4376 } 4377 4378 /* 4379 * Perform some tests on expressions which can't be done in build_binary() 4380 * and functions called by build_binary(). These tests must be done here 4381 * because we need some information about the context in which the operations 4382 * are performed. 4383 * After all tests are performed and dofreeblk is true, expr() frees the 4384 * memory which is used for the expression. 4385 */ 4386 void 4387 expr(tnode_t *tn, bool vctx, bool cond, bool dofreeblk, bool is_do_while) 4388 { 4389 4390 if (tn == NULL) { /* in case of errors */ 4391 expr_free_all(); 4392 return; 4393 } 4394 4395 /* expr() is also called in global initializations */ 4396 if (dcs->d_kind != DK_EXTERN && !is_do_while) 4397 check_statement_reachable(); 4398 4399 check_expr_misc(tn, vctx, cond, !cond, false, false, false); 4400 if (tn->tn_op == ASSIGN && !tn->tn_parenthesized) { 4401 if (hflag && cond) 4402 /* assignment in conditional context */ 4403 warning(159); 4404 } else if (tn->tn_op == CON) { 4405 if (hflag && cond && !constcond_flag && 4406 !tn->tn_system_dependent && 4407 !(is_do_while && 4408 is_constcond_false(tn, tn->tn_type->t_tspec))) 4409 /* constant in conditional context */ 4410 warning(161); 4411 } 4412 if (!modtab[tn->tn_op].m_has_side_effect) { 4413 /* 4414 * for left operands of COMMA this warning is already 4415 * printed 4416 */ 4417 if (tn->tn_op != COMMA && !vctx && !cond) 4418 check_null_effect(tn); 4419 } 4420 debug_node(tn); 4421 4422 /* free the tree memory */ 4423 if (dofreeblk) 4424 expr_free_all(); 4425 } 4426 4427 /* 4428 * Checks the range of array indices, if possible. 4429 * amper is set if only the address of the element is used. This 4430 * means that the index is allowed to refer to the first element 4431 * after the array. 4432 */ 4433 static void 4434 check_array_index(tnode_t *tn, bool amper) 4435 { 4436 const tnode_t *ln = tn->tn_left; 4437 const tnode_t *rn = tn->tn_right; 4438 4439 /* We can only check constant indices. */ 4440 if (rn->tn_op != CON) 4441 return; 4442 4443 /* Return if the left node does not stem from an array. */ 4444 if (ln->tn_op != ADDR) 4445 return; 4446 if (ln->tn_left->tn_op != STRING && ln->tn_left->tn_op != NAME) 4447 return; 4448 if (ln->tn_left->tn_type->t_tspec != ARRAY) 4449 return; 4450 4451 /* 4452 * For incomplete array types, we can print a warning only if 4453 * the index is negative. 4454 */ 4455 if (is_incomplete(ln->tn_left->tn_type) && rn->tn_val->v_quad >= 0) 4456 return; 4457 4458 /* Get the size of one array element */ 4459 int elsz = length_in_bits(ln->tn_type->t_subt, NULL); 4460 if (elsz == 0) 4461 return; 4462 elsz /= CHAR_SIZE; 4463 4464 /* Change the unit of the index from bytes to element size. */ 4465 int64_t con; 4466 if (is_uinteger(rn->tn_type->t_tspec)) 4467 con = (uint64_t)rn->tn_val->v_quad / elsz; 4468 else 4469 con = rn->tn_val->v_quad / elsz; 4470 4471 int dim = ln->tn_left->tn_type->t_dim + (amper ? 1 : 0); 4472 4473 if (!is_uinteger(rn->tn_type->t_tspec) && con < 0) { 4474 /* array subscript cannot be negative: %ld */ 4475 warning(167, (long)con); 4476 } else if (dim > 0 && (uint64_t)con >= (uint64_t)dim) { 4477 /* array subscript cannot be > %d: %ld */ 4478 warning(168, dim - 1, (long)con); 4479 } 4480 } 4481 4482 static void 4483 check_expr_addr(const tnode_t *ln, bool szof, bool fcall) 4484 { 4485 /* XXX: Taking warn_about_unreachable into account here feels wrong. */ 4486 if (ln->tn_op == NAME && (reached || !warn_about_unreachable)) { 4487 if (!szof) 4488 mark_as_set(ln->tn_sym); 4489 mark_as_used(ln->tn_sym, fcall, szof); 4490 } 4491 if (ln->tn_op == INDIR && ln->tn_left->tn_op == PLUS) 4492 /* check the range of array indices */ 4493 check_array_index(ln->tn_left, true); 4494 } 4495 4496 static void 4497 check_expr_load(const tnode_t *ln) 4498 { 4499 if (ln->tn_op == INDIR && ln->tn_left->tn_op == PLUS) 4500 /* check the range of array indices */ 4501 check_array_index(ln->tn_left, false); 4502 } 4503 4504 static void 4505 check_expr_side_effect(const tnode_t *ln, bool szof) 4506 { 4507 dinfo_t *di; 4508 4509 /* XXX: Taking warn_about_unreachable into account here feels wrong. */ 4510 if (ln->tn_op == NAME && (reached || !warn_about_unreachable)) { 4511 scl_t sc = ln->tn_sym->s_scl; 4512 /* 4513 * Look if there was a asm statement in one of the 4514 * compound statements we are in. If not, we don't 4515 * print a warning. 4516 */ 4517 for (di = dcs; di != NULL; di = di->d_enclosing) { 4518 if (di->d_asm) 4519 break; 4520 } 4521 if (sc != EXTERN && sc != STATIC && 4522 !ln->tn_sym->s_set && !szof && di == NULL) { 4523 /* '%s' may be used before set */ 4524 warning(158, ln->tn_sym->s_name); 4525 mark_as_set(ln->tn_sym); 4526 } 4527 mark_as_used(ln->tn_sym, false, false); 4528 } 4529 } 4530 4531 static void 4532 check_expr_assign(const tnode_t *ln, bool szof) 4533 { 4534 /* XXX: Taking warn_about_unreachable into account here feels wrong. */ 4535 if (ln->tn_op == NAME && !szof && (reached || !warn_about_unreachable)) { 4536 mark_as_set(ln->tn_sym); 4537 if (ln->tn_sym->s_scl == EXTERN) 4538 outusg(ln->tn_sym); 4539 } 4540 if (ln->tn_op == INDIR && ln->tn_left->tn_op == PLUS) 4541 /* check the range of array indices */ 4542 check_array_index(ln->tn_left, false); 4543 } 4544 4545 static void 4546 check_expr_call(const tnode_t *tn, const tnode_t *ln, 4547 bool szof, bool vctx, bool cond, bool retval_discarded) 4548 { 4549 lint_assert(ln->tn_op == ADDR); 4550 lint_assert(ln->tn_left->tn_op == NAME); 4551 if (!szof && 4552 !is_compiler_builtin(ln->tn_left->tn_sym->s_name)) 4553 outcall(tn, vctx || cond, retval_discarded); 4554 } 4555 4556 static bool 4557 check_expr_op(const tnode_t *tn, op_t op, const tnode_t *ln, 4558 bool szof, bool fcall, bool vctx, bool cond, 4559 bool retval_discarded, bool eqwarn) 4560 { 4561 switch (op) { 4562 case ADDR: 4563 check_expr_addr(ln, szof, fcall); 4564 break; 4565 case LOAD: 4566 check_expr_load(ln); 4567 /* FALLTHROUGH */ 4568 case PUSH: 4569 case INCBEF: 4570 case DECBEF: 4571 case INCAFT: 4572 case DECAFT: 4573 case ADDASS: 4574 case SUBASS: 4575 case MULASS: 4576 case DIVASS: 4577 case MODASS: 4578 case ANDASS: 4579 case ORASS: 4580 case XORASS: 4581 case SHLASS: 4582 case SHRASS: 4583 case REAL: 4584 case IMAG: 4585 check_expr_side_effect(ln, szof); 4586 break; 4587 case ASSIGN: 4588 check_expr_assign(ln, szof); 4589 break; 4590 case CALL: 4591 check_expr_call(tn, ln, szof, vctx, cond, retval_discarded); 4592 break; 4593 case EQ: 4594 if (hflag && eqwarn) 4595 /* operator '==' found where '=' was expected */ 4596 warning(160); 4597 break; 4598 case CON: 4599 case NAME: 4600 case STRING: 4601 return false; 4602 default: 4603 break; 4604 } 4605 return true; 4606 } 4607 4608 /* 4609 * vctx ??? 4610 * cond whether the expression is a condition that 4611 * will be compared with 0 4612 * eqwarn whether the operator '==' might be a 4613 * misspelled '=' 4614 * fcall whether the expression is a function call 4615 * retval_discarded whether the return value of a function call 4616 * is discarded; such calls will be analyzed by 4617 * lint2 in messages 4, 8 and 9 4618 * szof whether the expression is part of a sizeof 4619 * expression, which means that its value is 4620 * discarded since only the type is relevant 4621 */ 4622 void 4623 check_expr_misc(const tnode_t *tn, bool vctx, bool cond, 4624 bool eqwarn, bool fcall, bool retval_discarded, bool szof) 4625 { 4626 tnode_t *ln, *rn; 4627 const mod_t *mp; 4628 op_t op; 4629 bool cvctx, ccond, eq, discard; 4630 4631 if (tn == NULL) 4632 return; 4633 4634 ln = tn->tn_left; 4635 rn = tn->tn_right; 4636 mp = &modtab[op = tn->tn_op]; 4637 4638 if (!check_expr_op(tn, op, ln, 4639 szof, fcall, vctx, cond, retval_discarded, eqwarn)) 4640 return; 4641 4642 cvctx = mp->m_value_context; 4643 ccond = mp->m_compares_with_zero; 4644 eq = mp->m_warn_if_operand_eq && 4645 !ln->tn_parenthesized && 4646 rn != NULL && !rn->tn_parenthesized; 4647 4648 /* 4649 * values of operands of ':' are not used if the type of at least 4650 * one of the operands (for gcc compatibility) is void 4651 * XXX test/value context of QUEST should probably be used as 4652 * context for both operands of COLON 4653 */ 4654 if (op == COLON && tn->tn_type->t_tspec == VOID) 4655 cvctx = ccond = false; 4656 discard = op == CVT && tn->tn_type->t_tspec == VOID; 4657 check_expr_misc(ln, cvctx, ccond, eq, op == CALL, discard, szof); 4658 4659 switch (op) { 4660 case PUSH: 4661 if (rn != NULL) 4662 check_expr_misc(rn, false, false, eq, false, false, 4663 szof); 4664 break; 4665 case LOGAND: 4666 case LOGOR: 4667 check_expr_misc(rn, false, true, eq, false, false, szof); 4668 break; 4669 case COLON: 4670 check_expr_misc(rn, cvctx, ccond, eq, false, false, szof); 4671 break; 4672 case COMMA: 4673 check_expr_misc(rn, vctx, cond, false, false, false, szof); 4674 break; 4675 default: 4676 if (mp->m_binary) 4677 check_expr_misc(rn, true, false, eq, false, false, 4678 szof); 4679 break; 4680 } 4681 } 4682 4683 /* 4684 * Return whether the expression can be used for static initialization. 4685 * 4686 * Constant initialization expressions must be constant or an address 4687 * of a static object with an optional offset. In the first case, 4688 * the result is returned in *offsp. In the second case, the static 4689 * object is returned in *symp and the offset in *offsp. 4690 * 4691 * The expression can consist of PLUS, MINUS, ADDR, NAME, STRING and 4692 * CON. Type conversions are allowed if they do not change binary 4693 * representation (including width). 4694 * 4695 * C99 6.6 "Constant expressions" 4696 * C99 6.7.8p4 restricts initializers for static storage duration 4697 */ 4698 bool 4699 constant_addr(const tnode_t *tn, const sym_t **symp, ptrdiff_t *offsp) 4700 { 4701 const sym_t *sym; 4702 ptrdiff_t offs1, offs2; 4703 tspec_t t, ot; 4704 4705 switch (tn->tn_op) { 4706 case MINUS: 4707 if (tn->tn_right->tn_op == CVT) 4708 return constant_addr(tn->tn_right, symp, offsp); 4709 else if (tn->tn_right->tn_op != CON) 4710 return false; 4711 /* FALLTHROUGH */ 4712 case PLUS: 4713 offs1 = offs2 = 0; 4714 if (tn->tn_left->tn_op == CON) { 4715 offs1 = (ptrdiff_t)tn->tn_left->tn_val->v_quad; 4716 if (!constant_addr(tn->tn_right, &sym, &offs2)) 4717 return false; 4718 } else if (tn->tn_right->tn_op == CON) { 4719 offs2 = (ptrdiff_t)tn->tn_right->tn_val->v_quad; 4720 if (tn->tn_op == MINUS) 4721 offs2 = -offs2; 4722 if (!constant_addr(tn->tn_left, &sym, &offs1)) 4723 return false; 4724 } else { 4725 return false; 4726 } 4727 *symp = sym; 4728 *offsp = offs1 + offs2; 4729 return true; 4730 case ADDR: 4731 if (tn->tn_left->tn_op == NAME) { 4732 *symp = tn->tn_left->tn_sym; 4733 *offsp = 0; 4734 return true; 4735 } else { 4736 /* 4737 * If this would be the front end of a compiler we 4738 * would return a label instead of 0, at least if 4739 * 'tn->tn_left->tn_op == STRING'. 4740 */ 4741 *symp = NULL; 4742 *offsp = 0; 4743 return true; 4744 } 4745 case CVT: 4746 t = tn->tn_type->t_tspec; 4747 ot = tn->tn_left->tn_type->t_tspec; 4748 if ((!is_integer(t) && t != PTR) || 4749 (!is_integer(ot) && ot != PTR)) { 4750 return false; 4751 } 4752 #if 0 4753 /* 4754 * consider: 4755 * struct foo { 4756 * unsigned char a; 4757 * } f = { 4758 * (unsigned char)(unsigned long) 4759 * (&(((struct foo *)0)->a)) 4760 * }; 4761 * since psize(unsigned long) != psize(unsigned char), 4762 * this fails. 4763 */ 4764 else if (psize(t) != psize(ot)) 4765 return -1; 4766 #endif 4767 return constant_addr(tn->tn_left, symp, offsp); 4768 default: 4769 return false; 4770 } 4771 } 4772 4773 /* Append s2 to s1, then free s2. */ 4774 strg_t * 4775 cat_strings(strg_t *s1, strg_t *s2) 4776 { 4777 4778 if (s1->st_char != s2->st_char) { 4779 /* cannot concatenate wide and regular string literals */ 4780 error(292); 4781 return s1; 4782 } 4783 4784 size_t len1 = s1->st_len; 4785 size_t len2 = s2->st_len; 4786 size_t chsize = s1->st_char ? sizeof(char) : sizeof(wchar_t); 4787 size_t size1 = len1 * chsize; 4788 size_t size2 = (len2 + 1) * chsize; 4789 s1->st_mem = xrealloc(s1->st_mem, size1 + size2); 4790 memcpy((char *)s1->st_mem + size1, s2->st_mem, size2); 4791 free(s2->st_mem); 4792 4793 s1->st_len = len1 + len2; 4794 free(s2); 4795 4796 return s1; 4797 } 4798 4799 4800 typedef struct stmt_expr { 4801 memory_pool se_mem; 4802 sym_t *se_sym; 4803 struct stmt_expr *se_enclosing; 4804 } stmt_expr; 4805 4806 static stmt_expr *stmt_exprs; 4807 4808 void 4809 begin_statement_expr(void) 4810 { 4811 stmt_expr *se = xmalloc(sizeof(*se)); 4812 se->se_mem = expr_save_memory(); 4813 se->se_sym = NULL; 4814 se->se_enclosing = stmt_exprs; 4815 stmt_exprs = se; 4816 } 4817 4818 void 4819 do_statement_expr(tnode_t *tn) 4820 { 4821 block_level--; 4822 mem_block_level--; 4823 stmt_exprs->se_sym = tn != NULL 4824 ? mktempsym(block_dup_type(tn->tn_type)) 4825 : NULL; /* after a syntax error */ 4826 mem_block_level++; 4827 block_level++; 4828 /* ({ }) is a GCC extension */ 4829 gnuism(320); 4830 } 4831 4832 tnode_t * 4833 end_statement_expr(void) 4834 { 4835 stmt_expr *se = stmt_exprs; 4836 if (se->se_sym == NULL) 4837 return NULL; /* after a syntax error */ 4838 tnode_t *tn = build_name(se->se_sym, false); 4839 (void)expr_save_memory(); /* leak */ 4840 expr_restore_memory(se->se_mem); 4841 stmt_exprs = se->se_enclosing; 4842 free(se); 4843 return tn; 4844 } 4845
Indexes created Thu Sep 25 06:09:39 GMT 2025