tree.c revision 1.588
1 /* $NetBSD: tree.c,v 1.588 2024/01/06 14:21:26 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 1.588 2024/01/06 14:21:26 rillig Exp $"); 41 #endif 42 43 #include <float.h> 44 #include <limits.h> 45 #include <math.h> 46 #include <signal.h> 47 #include <stdlib.h> 48 #include <string.h> 49 50 #include "lint1.h" 51 52 53 typedef struct integer_constraints { 54 int64_t smin; /* signed minimum */ 55 int64_t smax; /* signed maximum */ 56 uint64_t umin; /* unsigned minimum */ 57 uint64_t umax; /* unsigned maximum */ 58 uint64_t bset; /* bits that are definitely set */ 59 uint64_t bclr; /* bits that are definitely clear */ 60 } integer_constraints; 61 62 63 static uint64_t 64 u64_fill_right(uint64_t x) 65 { 66 x |= x >> 1; 67 x |= x >> 2; 68 x |= x >> 4; 69 x |= x >> 8; 70 x |= x >> 16; 71 x |= x >> 32; 72 return x; 73 } 74 75 static bool 76 str_ends_with(const char *haystack, const char *needle) 77 { 78 size_t hlen = strlen(haystack); 79 size_t nlen = strlen(needle); 80 81 return nlen <= hlen && 82 memcmp(haystack + hlen - nlen, needle, nlen) == 0; 83 } 84 85 static unsigned 86 width_in_bits(const type_t *tp) 87 { 88 89 lint_assert(is_integer(tp->t_tspec)); 90 return tp->t_bitfield 91 ? tp->t_bit_field_width 92 : size_in_bits(tp->t_tspec); 93 } 94 95 static int 96 portable_rank_cmp(tspec_t t1, tspec_t t2) 97 { 98 const ttab_t *p1 = type_properties(t1), *p2 = type_properties(t2); 99 lint_assert(p1->tt_rank_kind == p2->tt_rank_kind); 100 lint_assert(p1->tt_rank_value > 0); 101 lint_assert(p2->tt_rank_value > 0); 102 return (int)p1->tt_rank_value - (int)p2->tt_rank_value; 103 } 104 105 static bool 106 ic_maybe_signed(const type_t *tp, const integer_constraints *ic) 107 { 108 return !is_uinteger(tp->t_tspec) && ic->bclr >> 63 == 0; 109 } 110 111 static integer_constraints 112 ic_any(const type_t *tp) 113 { 114 integer_constraints c; 115 116 uint64_t vbits = value_bits(width_in_bits(tp)); 117 if (is_uinteger(tp->t_tspec)) { 118 c.smin = INT64_MIN; 119 c.smax = INT64_MAX; 120 c.umin = 0; 121 c.umax = vbits; 122 c.bset = 0; 123 c.bclr = ~c.umax; 124 } else { 125 c.smin = (int64_t)-1 - (int64_t)(vbits >> 1); 126 c.smax = (int64_t)(vbits >> 1); 127 c.umin = 0; 128 c.umax = UINT64_MAX; 129 c.bset = 0; 130 c.bclr = 0; 131 } 132 return c; 133 } 134 135 static integer_constraints 136 ic_con(const type_t *tp, const val_t *v) 137 { 138 integer_constraints c; 139 140 lint_assert(is_integer(tp->t_tspec)); 141 int64_t si = v->u.integer; 142 uint64_t ui = (uint64_t)si; 143 c.smin = si; 144 c.smax = si; 145 c.umin = ui; 146 c.umax = ui; 147 c.bset = ui; 148 c.bclr = ~ui; 149 return c; 150 } 151 152 static integer_constraints 153 ic_cvt(const type_t *ntp, const type_t *otp, integer_constraints a) 154 { 155 unsigned nw = width_in_bits(ntp); 156 unsigned ow = width_in_bits(otp); 157 bool nu = is_uinteger(ntp->t_tspec); 158 bool ou = is_uinteger(otp->t_tspec); 159 160 if (nw >= ow && nu == ou) 161 return a; 162 if (nw > ow && ou) 163 return a; 164 return ic_any(ntp); 165 } 166 167 static integer_constraints 168 ic_bitand(integer_constraints a, integer_constraints b) 169 { 170 integer_constraints c; 171 172 c.smin = INT64_MIN; 173 c.smax = INT64_MAX; 174 c.umin = 0; 175 c.umax = UINT64_MAX; 176 c.bset = a.bset & b.bset; 177 c.bclr = a.bclr | b.bclr; 178 return c; 179 } 180 181 static integer_constraints 182 ic_bitor(integer_constraints a, integer_constraints b) 183 { 184 integer_constraints c; 185 186 c.smin = INT64_MIN; 187 c.smax = INT64_MAX; 188 c.umin = 0; 189 c.umax = UINT64_MAX; 190 c.bset = a.bset | b.bset; 191 c.bclr = a.bclr & b.bclr; 192 return c; 193 } 194 195 static integer_constraints 196 ic_mod(const type_t *tp, integer_constraints a, integer_constraints b) 197 { 198 integer_constraints c; 199 200 if (ic_maybe_signed(tp, &a) || ic_maybe_signed(tp, &b)) 201 return ic_any(tp); 202 203 c.smin = INT64_MIN; 204 c.smax = INT64_MAX; 205 c.umin = 0; 206 c.umax = b.umax - 1; 207 c.bset = 0; 208 c.bclr = ~u64_fill_right(c.umax); 209 return c; 210 } 211 212 static integer_constraints 213 ic_shl(const type_t *tp, integer_constraints a, integer_constraints b) 214 { 215 integer_constraints c; 216 unsigned int amount; 217 218 if (ic_maybe_signed(tp, &a)) 219 return ic_any(tp); 220 221 if (b.smin == b.smax && b.smin >= 0 && b.smin < 64) 222 amount = (unsigned int)b.smin; 223 else if (b.umin == b.umax && b.umin < 64) 224 amount = (unsigned int)b.umin; 225 else 226 return ic_any(tp); 227 228 c.smin = INT64_MIN; 229 c.smax = INT64_MAX; 230 c.umin = 0; 231 c.umax = UINT64_MAX; 232 c.bset = a.bset << amount; 233 c.bclr = a.bclr << amount | (((uint64_t)1 << amount) - 1); 234 return c; 235 } 236 237 static integer_constraints 238 ic_shr(const type_t *tp, integer_constraints a, integer_constraints b) 239 { 240 integer_constraints c; 241 unsigned int amount; 242 243 if (ic_maybe_signed(tp, &a)) 244 return ic_any(tp); 245 246 if (b.smin == b.smax && b.smin >= 0 && b.smin < 64) 247 amount = (unsigned int)b.smin; 248 else if (b.umin == b.umax && b.umin < 64) 249 amount = (unsigned int)b.umin; 250 else 251 return ic_any(tp); 252 253 c.smin = INT64_MIN; 254 c.smax = INT64_MAX; 255 c.umin = 0; 256 c.umax = UINT64_MAX; 257 c.bset = a.bset >> amount; 258 c.bclr = a.bclr >> amount | ~(~(uint64_t)0 >> amount); 259 return c; 260 } 261 262 static integer_constraints 263 ic_cond(integer_constraints a, integer_constraints b) 264 { 265 integer_constraints c; 266 267 c.smin = a.smin < b.smin ? a.smin : b.smin; 268 c.smax = a.smax > b.smax ? a.smax : b.smax; 269 c.umin = a.umin < b.umin ? a.umin : b.umin; 270 c.umax = a.umax > b.umax ? a.umax : b.umax; 271 c.bset = a.bset | b.bset; 272 c.bclr = a.bclr & b.bclr; 273 return c; 274 } 275 276 static integer_constraints 277 ic_expr(const tnode_t *tn) 278 { 279 integer_constraints lc, rc; 280 281 lint_assert(is_integer(tn->tn_type->t_tspec)); 282 283 switch (tn->tn_op) { 284 case CON: 285 return ic_con(tn->tn_type, &tn->tn_val); 286 case CVT: 287 if (!is_integer(tn->tn_left->tn_type->t_tspec)) 288 return ic_any(tn->tn_type); 289 lc = ic_expr(tn->tn_left); 290 return ic_cvt(tn->tn_type, tn->tn_left->tn_type, lc); 291 case MOD: 292 lc = ic_expr(before_conversion(tn->tn_left)); 293 rc = ic_expr(before_conversion(tn->tn_right)); 294 return ic_mod(tn->tn_type, lc, rc); 295 case SHL: 296 lc = ic_expr(tn->tn_left); 297 rc = ic_expr(tn->tn_right); 298 return ic_shl(tn->tn_type, lc, rc); 299 case SHR: 300 lc = ic_expr(tn->tn_left); 301 rc = ic_expr(tn->tn_right); 302 return ic_shr(tn->tn_type, lc, rc); 303 case BITAND: 304 lc = ic_expr(tn->tn_left); 305 rc = ic_expr(tn->tn_right); 306 return ic_bitand(lc, rc); 307 case BITOR: 308 lc = ic_expr(tn->tn_left); 309 rc = ic_expr(tn->tn_right); 310 return ic_bitor(lc, rc); 311 case QUEST: 312 lc = ic_expr(tn->tn_right->tn_left); 313 rc = ic_expr(tn->tn_right->tn_right); 314 return ic_cond(lc, rc); 315 default: 316 return ic_any(tn->tn_type); 317 } 318 } 319 320 /* Build 'pointer to tp', 'array of tp' or 'function returning tp'. */ 321 type_t * 322 block_derive_type(type_t *tp, tspec_t t) 323 { 324 type_t *tp2; 325 326 tp2 = block_zero_alloc(sizeof(*tp2), "type"); 327 tp2->t_tspec = t; 328 tp2->t_subt = tp; 329 return tp2; 330 } 331 332 /* 333 * Derive 'pointer to tp' or 'function returning tp'. 334 * The memory is freed at the end of the current expression. 335 */ 336 type_t * 337 expr_derive_type(type_t *tp, tspec_t t) 338 { 339 type_t *tp2; 340 341 tp2 = expr_zero_alloc(sizeof(*tp2), "type"); 342 tp2->t_tspec = t; 343 tp2->t_subt = tp; 344 return tp2; 345 } 346 347 /* Create an expression from a unary or binary operator and its operands. */ 348 static tnode_t * 349 build_op(op_t op, bool sys, type_t *type, tnode_t *ln, tnode_t *rn) 350 { 351 352 tnode_t *ntn = expr_alloc_tnode(); 353 ntn->tn_op = op; 354 ntn->tn_type = type; 355 ntn->tn_sys = sys; 356 ntn->tn_left = ln; 357 ntn->tn_right = rn; 358 359 if (op == INDIR || op == FSEL) { 360 lint_assert(ln->tn_type->t_tspec == PTR); 361 tspec_t t = ln->tn_type->t_subt->t_tspec; 362 ntn->tn_lvalue = t != FUNC && t != VOID; 363 } 364 365 return ntn; 366 } 367 368 tnode_t * 369 build_constant(type_t *tp, val_t *v) 370 { 371 372 tnode_t *n = expr_alloc_tnode(); 373 n->tn_op = CON; 374 n->tn_type = tp; 375 n->tn_val = *v; 376 n->tn_val.v_tspec = tp->t_tspec; 377 free(v); 378 return n; 379 } 380 381 static tnode_t * 382 build_integer_constant(tspec_t t, int64_t si) 383 { 384 385 tnode_t *n = expr_alloc_tnode(); 386 n->tn_op = CON; 387 n->tn_type = gettyp(t); 388 n->tn_val.v_tspec = t; 389 n->tn_val.v_unsigned_since_c90 = false; 390 n->tn_val.v_char_constant = false; 391 n->tn_val.u.integer = si; 392 return n; 393 } 394 395 static void 396 fallback_symbol(sym_t *sym) 397 { 398 399 if (Tflag && fallback_symbol_strict_bool(sym)) 400 return; 401 402 if (block_level > 0 && (strcmp(sym->s_name, "__FUNCTION__") == 0 || 403 strcmp(sym->s_name, "__PRETTY_FUNCTION__") == 0)) { 404 /* __FUNCTION__/__PRETTY_FUNCTION__ is a GCC extension */ 405 gnuism(316); 406 // XXX: Should probably be ARRAY instead of PTR. 407 sym->s_type = block_derive_type(gettyp(CHAR), PTR); 408 sym->s_type->t_const = true; 409 return; 410 } 411 412 if (block_level > 0 && strcmp(sym->s_name, "__func__") == 0) { 413 if (!allow_c99) 414 /* __func__ is a C99 feature */ 415 warning(317); 416 /* C11 6.4.2.2 */ 417 sym->s_type = block_derive_type(gettyp(CHAR), ARRAY); 418 sym->s_type->t_const = true; 419 sym->s_type->t_dim = (int)strlen(funcsym->s_name) + 1; 420 return; 421 } 422 423 /* '%s' undefined */ 424 error(99, sym->s_name); 425 } 426 427 /* 428 * Functions that are predeclared by GCC or other compilers can be called 429 * with arbitrary arguments. Since lint usually runs after a successful 430 * compilation, it's the compiler's job to catch any errors. 431 */ 432 bool 433 is_compiler_builtin(const char *name) 434 { 435 /* https://gcc.gnu.org/onlinedocs/gcc/C-Extensions.html */ 436 if (allow_gcc) { 437 if (strncmp(name, "__atomic_", 9) == 0 || 438 strncmp(name, "__builtin_", 10) == 0 || 439 strcmp(name, "alloca") == 0 || 440 /* obsolete but still in use, as of 2021 */ 441 strncmp(name, "__sync_", 7) == 0) 442 return true; 443 } 444 445 /* https://software.intel.com/sites/landingpage/IntrinsicsGuide/ */ 446 if (strncmp(name, "_mm_", 4) == 0) 447 return true; 448 449 return false; 450 } 451 452 /* https://gcc.gnu.org/onlinedocs/gcc/Integer-Overflow-Builtins.html */ 453 static bool 454 is_gcc_bool_builtin(const char *name) 455 { 456 return strncmp(name, "__builtin_", 10) == 0 && 457 (str_ends_with(name, "_overflow") || 458 str_ends_with(name, "_overflow_p")); 459 } 460 461 static void 462 build_name_call(sym_t *sym) 463 { 464 465 if (is_compiler_builtin(sym->s_name)) { 466 /* 467 * Do not warn about these, just assume that they are regular 468 * functions compatible with non-prototype calling conventions. 469 */ 470 if (allow_gcc && is_gcc_bool_builtin(sym->s_name)) 471 sym->s_type = gettyp(BOOL); 472 } else if (allow_c99) { 473 /* function '%s' implicitly declared to return int */ 474 error(215, sym->s_name); 475 } else if (!allow_trad) { 476 /* function '%s' implicitly declared to return int */ 477 warning(215, sym->s_name); 478 } 479 480 /* XXX if !allow_c90, the symbol should be exported to level 0 */ 481 sym->s_type = block_derive_type(sym->s_type, FUNC); 482 } 483 484 /* Create a node for a name (symbol table entry). */ 485 tnode_t * 486 build_name(sym_t *sym, bool is_funcname) 487 { 488 489 if (sym->s_scl == NO_SCL && !in_gcc_attribute) { 490 sym->s_scl = EXTERN; 491 sym->s_def = DECL; 492 if (is_funcname) 493 build_name_call(sym); 494 else 495 fallback_symbol(sym); 496 } 497 498 lint_assert(sym->s_kind == FVFT || sym->s_kind == FMEMBER); 499 500 tnode_t *n = expr_alloc_tnode(); 501 n->tn_type = sym->s_type; 502 if (sym->s_scl == BOOL_CONST) { 503 n->tn_op = CON; 504 n->tn_val.v_tspec = BOOL; 505 n->tn_val.v_unsigned_since_c90 = false; 506 n->tn_val.v_char_constant = false; 507 n->tn_val.u.integer = sym->u.s_bool_constant ? 1 : 0; 508 } else if (sym->s_scl == ENUM_CONST) { 509 n->tn_op = CON; 510 n->tn_val.v_tspec = INT; /* ENUM is in n->tn_type */ 511 n->tn_val.v_unsigned_since_c90 = false; 512 n->tn_val.v_char_constant = false; 513 n->tn_val.u.integer = sym->u.s_enum_constant; 514 } else { 515 n->tn_op = NAME; 516 n->tn_sym = sym; 517 if (sym->s_kind == FVFT && sym->s_type->t_tspec != FUNC) 518 n->tn_lvalue = true; 519 } 520 521 return n; 522 } 523 524 tnode_t * 525 build_string(strg_t *strg) 526 { 527 size_t len = strg->st_len; 528 529 type_t *tp = expr_zero_alloc(sizeof(*tp), "type"); 530 tp->t_tspec = ARRAY; 531 tp->t_subt = gettyp(strg->st_char ? CHAR : WCHAR_TSPEC); 532 tp->t_dim = (int)(len + 1); 533 534 tnode_t *n = expr_alloc_tnode(); 535 n->tn_op = STRING; 536 n->tn_type = tp; 537 n->tn_lvalue = true; 538 539 n->tn_string = expr_zero_alloc(sizeof(*n->tn_string), "type.string"); 540 n->tn_string->st_char = strg->st_char; 541 n->tn_string->st_len = len; 542 543 size_t chsize = strg->st_char ? sizeof(char) : sizeof(wchar_t); 544 size_t size = (len + 1) * chsize; 545 n->tn_string->st_mem = expr_zero_alloc(size, "type.string.data"); 546 (void)memcpy(n->tn_string->st_mem, strg->st_mem, size); 547 free(strg->st_mem); 548 free(strg); 549 550 return n; 551 } 552 553 tnode_t * 554 build_generic_selection(const tnode_t *expr, 555 struct generic_association *sel) 556 { 557 tnode_t *default_result = NULL; 558 559 for (; sel != NULL; sel = sel->ga_prev) { 560 if (expr != NULL && 561 types_compatible(sel->ga_arg, expr->tn_type, 562 false, false, NULL)) 563 return sel->ga_result; 564 else if (sel->ga_arg == NULL) 565 default_result = sel->ga_result; 566 } 567 return default_result; 568 } 569 570 static bool 571 is_out_of_char_range(const tnode_t *tn) 572 { 573 return tn->tn_op == CON && 574 !tn->tn_val.v_char_constant && 575 !(0 <= tn->tn_val.u.integer && 576 tn->tn_val.u.integer < 1 << (CHAR_SIZE - 1)); 577 } 578 579 static bool 580 check_nonportable_char_comparison(op_t op, 581 const tnode_t *ln, tspec_t lt, 582 const tnode_t *rn, tspec_t rt) 583 { 584 if (!(hflag || pflag)) 585 return true; 586 587 if (lt == CHAR && is_out_of_char_range(rn)) { 588 char buf[128]; 589 (void)snprintf(buf, sizeof(buf), "%s %d", 590 op_name(op), (int)rn->tn_val.u.integer); 591 /* nonportable character comparison '%s' */ 592 warning(230, buf); 593 return false; 594 } 595 if (rt == CHAR && is_out_of_char_range(ln)) { 596 char buf[128]; 597 (void)snprintf(buf, sizeof(buf), "%d %s ?", 598 (int)ln->tn_val.u.integer, op_name(op)); 599 /* nonportable character comparison '%s' */ 600 warning(230, buf); 601 return false; 602 } 603 return true; 604 } 605 606 static void 607 check_integer_comparison(op_t op, tnode_t *ln, tnode_t *rn) 608 { 609 610 tspec_t lt = ln->tn_type->t_tspec; 611 tspec_t rt = rn->tn_type->t_tspec; 612 613 if (ln->tn_op != CON && rn->tn_op != CON) 614 return; 615 616 if (!is_integer(lt) || !is_integer(rt)) 617 return; 618 619 if (any_query_enabled && !in_system_header) { 620 if (lt == CHAR && rn->tn_op == CON && 621 !rn->tn_val.v_char_constant) { 622 /* comparison '%s' of 'char' with plain integer %d */ 623 query_message(14, 624 op_name(op), (int)rn->tn_val.u.integer); 625 } 626 if (rt == CHAR && ln->tn_op == CON && 627 !ln->tn_val.v_char_constant) { 628 /* comparison '%s' of 'char' with plain integer %d */ 629 query_message(14, 630 op_name(op), (int)ln->tn_val.u.integer); 631 } 632 } 633 634 if (!check_nonportable_char_comparison(op, ln, lt, rn, rt)) 635 return; 636 637 if (is_uinteger(lt) && !is_uinteger(rt) && 638 rn->tn_op == CON && rn->tn_val.u.integer <= 0) { 639 if (rn->tn_val.u.integer < 0) { 640 /* operator '%s' compares '%s' with '%s' */ 641 warning(162, op_name(op), 642 type_name(ln->tn_type), "negative constant"); 643 } else if (op == LT || op == GE) { 644 /* operator '%s' compares '%s' with '%s' */ 645 warning(162, op_name(op), type_name(ln->tn_type), "0"); 646 } 647 return; 648 } 649 if (is_uinteger(rt) && !is_uinteger(lt) && 650 ln->tn_op == CON && ln->tn_val.u.integer <= 0) { 651 if (ln->tn_val.u.integer < 0) { 652 /* operator '%s' compares '%s' with '%s' */ 653 warning(162, op_name(op), 654 "negative constant", type_name(rn->tn_type)); 655 } else if (op == GT || op == LE) { 656 /* operator '%s' compares '%s' with '%s' */ 657 warning(162, op_name(op), "0", type_name(rn->tn_type)); 658 } 659 return; 660 } 661 } 662 663 static const tspec_t arith_rank[] = { 664 LDOUBLE, DOUBLE, FLOAT, 665 #ifdef INT128_SIZE 666 UINT128, INT128, 667 #endif 668 ULLONG, LLONG, 669 ULONG, LONG, 670 UINT, INT, 671 }; 672 673 /* Keep unsigned in traditional C */ 674 static tspec_t 675 usual_arithmetic_conversion_trad(tspec_t lt, tspec_t rt) 676 { 677 678 size_t i; 679 for (i = 0; arith_rank[i] != INT; i++) 680 if (lt == arith_rank[i] || rt == arith_rank[i]) 681 break; 682 683 tspec_t t = arith_rank[i]; 684 if (is_uinteger(lt) || is_uinteger(rt)) 685 if (is_integer(t) && !is_uinteger(t)) 686 return unsigned_type(t); 687 return t; 688 } 689 690 static tspec_t 691 usual_arithmetic_conversion_c90(tspec_t lt, tspec_t rt) 692 { 693 694 if (lt == rt) 695 return lt; 696 697 if (lt == LCOMPLEX || rt == LCOMPLEX) 698 return LCOMPLEX; 699 if (lt == DCOMPLEX || rt == DCOMPLEX) 700 return DCOMPLEX; 701 if (lt == FCOMPLEX || rt == FCOMPLEX) 702 return FCOMPLEX; 703 if (lt == LDOUBLE || rt == LDOUBLE) 704 return LDOUBLE; 705 if (lt == DOUBLE || rt == DOUBLE) 706 return DOUBLE; 707 if (lt == FLOAT || rt == FLOAT) 708 return FLOAT; 709 710 if (size_in_bits(lt) > size_in_bits(rt)) 711 return lt; 712 if (size_in_bits(lt) < size_in_bits(rt)) 713 return rt; 714 715 size_t i; 716 for (i = 3; arith_rank[i] != INT; i++) 717 if (arith_rank[i] == lt || arith_rank[i] == rt) 718 break; 719 if ((is_uinteger(lt) || is_uinteger(rt)) && 720 !is_uinteger(arith_rank[i])) 721 i--; 722 return arith_rank[i]; 723 } 724 725 static tnode_t * 726 apply_usual_arithmetic_conversions(op_t op, tnode_t *tn, tspec_t t) 727 { 728 type_t *ntp = expr_dup_type(tn->tn_type); 729 ntp->t_tspec = t; 730 if (tn->tn_op != CON) { 731 /* usual arithmetic conversion for '%s' from '%s' to '%s' */ 732 query_message(4, op_name(op), 733 type_name(tn->tn_type), type_name(ntp)); 734 } 735 return convert(op, 0, ntp, tn); 736 } 737 738 /* 739 * Apply the "usual arithmetic conversions" (C99 6.3.1.8), which gives both 740 * operands the same type. 741 */ 742 static void 743 balance(op_t op, tnode_t **lnp, tnode_t **rnp) 744 { 745 746 tspec_t lt = (*lnp)->tn_type->t_tspec; 747 tspec_t rt = (*rnp)->tn_type->t_tspec; 748 if (!is_arithmetic(lt) || !is_arithmetic(rt)) 749 return; 750 751 tspec_t t = allow_c90 752 ? usual_arithmetic_conversion_c90(lt, rt) 753 : usual_arithmetic_conversion_trad(lt, rt); 754 755 if (t != lt) 756 *lnp = apply_usual_arithmetic_conversions(op, *lnp, t); 757 if (t != rt) 758 *rnp = apply_usual_arithmetic_conversions(op, *rnp, t); 759 } 760 761 static tnode_t * 762 build_address(bool sys, tnode_t *tn, bool noign) 763 { 764 tspec_t t; 765 766 if (!noign && ((t = tn->tn_type->t_tspec) == ARRAY || t == FUNC)) { 767 if (!allow_c90) 768 /* '&' before array or function: ignored */ 769 warning(127); 770 return tn; 771 } 772 773 /* eliminate &* */ 774 if (tn->tn_op == INDIR && 775 tn->tn_left->tn_type->t_tspec == PTR && 776 tn->tn_left->tn_type->t_subt == tn->tn_type) { 777 return tn->tn_left; 778 } 779 780 return build_op(ADDR, sys, expr_derive_type(tn->tn_type, PTR), 781 tn, NULL); 782 } 783 784 /* 785 * XXX 786 * Note: There appear to be a number of bugs in detecting overflow in 787 * this function. An audit and a set of proper regression tests are needed. 788 * --Perry Metzger, Nov. 16, 2001 789 */ 790 /* 791 * Do only as much as necessary to compute constant expressions. 792 * Called only if the operator allows folding and all operands are constants. 793 */ 794 static tnode_t * 795 fold(tnode_t *tn) 796 { 797 798 val_t *v = xcalloc(1, sizeof(*v)); 799 v->v_tspec = tn->tn_type->t_tspec; 800 801 lint_assert(has_operands(tn)); 802 tspec_t t = tn->tn_left->tn_type->t_tspec; 803 bool utyp = !is_integer(t) || is_uinteger(t); 804 int64_t sl = tn->tn_left->tn_val.u.integer, sr = 0; 805 uint64_t ul = sl, ur = 0; 806 if (is_binary(tn)) 807 ur = sr = tn->tn_right->tn_val.u.integer; 808 809 int64_t mask = (int64_t)value_bits(size_in_bits(t)); 810 bool ovfl = false; 811 812 int64_t si; 813 switch (tn->tn_op) { 814 case UPLUS: 815 si = sl; 816 break; 817 case UMINUS: 818 si = sl == INT64_MIN ? sl : -sl; 819 if (sl != 0 && msb(si, t) == msb(sl, t)) 820 ovfl = true; 821 break; 822 case COMPL: 823 si = ~sl; 824 break; 825 case MULT: 826 if (utyp) { 827 si = (int64_t)(ul * ur); 828 if (si != (si & mask)) 829 ovfl = true; 830 else if ((ul != 0) && ((si / ul) != ur)) 831 ovfl = true; 832 } else { 833 si = sl * sr; 834 if (msb(si, t) != (msb(sl, t) ^ msb(sr, t))) 835 ovfl = true; 836 } 837 break; 838 case DIV: 839 if (sr == 0) { 840 /* division by 0 */ 841 error(139); 842 si = utyp ? -1 : INT64_MAX; 843 } else { 844 si = utyp ? (int64_t)(ul / ur) : sl / sr; 845 } 846 break; 847 case MOD: 848 if (sr == 0) { 849 /* modulus by 0 */ 850 error(140); 851 si = 0; 852 } else { 853 si = utyp ? (int64_t)(ul % ur) : sl % sr; 854 } 855 break; 856 case PLUS: 857 si = utyp ? (int64_t)(ul + ur) : sl + sr; 858 if (msb(sl, t) && msb(sr, t) && !msb(si, t)) 859 ovfl = true; 860 if (!utyp && !msb(sl, t) && !msb(sr, t) && msb(si, t)) 861 ovfl = true; 862 break; 863 case MINUS: 864 si = utyp ? (int64_t)(ul - ur) : sl - sr; 865 if (!utyp && msb(sl, t) && !msb(sr, t) && !msb(si, t)) 866 ovfl = true; 867 if (!msb(sl, t) && msb(sr, t) && msb(si, t)) 868 ovfl = true; 869 break; 870 case SHL: 871 /* TODO: warn about out-of-bounds 'sr'. */ 872 /* TODO: warn about overflow in signed '<<'. */ 873 si = utyp ? (int64_t)(ul << (sr & 63)) : sl << (sr & 63); 874 break; 875 case SHR: 876 /* 877 * The sign must be explicitly extended because shifts of 878 * signed values are implementation dependent. 879 */ 880 /* TODO: warn about out-of-bounds 'sr'. */ 881 si = (int64_t)(ul >> (sr & 63)); 882 si = convert_integer(si, t, size_in_bits(t) - (int)sr); 883 break; 884 case LT: 885 si = (utyp ? ul < ur : sl < sr) ? 1 : 0; 886 break; 887 case LE: 888 si = (utyp ? ul <= ur : sl <= sr) ? 1 : 0; 889 break; 890 case GE: 891 si = (utyp ? ul >= ur : sl >= sr) ? 1 : 0; 892 break; 893 case GT: 894 si = (utyp ? ul > ur : sl > sr) ? 1 : 0; 895 break; 896 case EQ: 897 si = (utyp ? ul == ur : sl == sr) ? 1 : 0; 898 break; 899 case NE: 900 si = (utyp ? ul != ur : sl != sr) ? 1 : 0; 901 break; 902 case BITAND: 903 si = utyp ? (int64_t)(ul & ur) : sl & sr; 904 break; 905 case BITXOR: 906 si = utyp ? (int64_t)(ul ^ ur) : sl ^ sr; 907 break; 908 case BITOR: 909 si = utyp ? (int64_t)(ul | ur) : sl | sr; 910 break; 911 default: 912 lint_assert(/*CONSTCOND*/false); 913 } 914 915 /* XXX: The overflow check does not work for 64-bit integers. */ 916 if (ovfl || 917 ((uint64_t)(si | mask) != ~(uint64_t)0 && (si & ~mask) != 0)) { 918 if (hflag) 919 /* operator '%s' produces integer overflow */ 920 warning(141, op_name(tn->tn_op)); 921 } 922 923 v->u.integer = convert_integer(si, t, 0); 924 925 tnode_t *cn = build_constant(tn->tn_type, v); 926 if (tn->tn_left->tn_system_dependent) 927 cn->tn_system_dependent = true; 928 if (is_binary(tn) && tn->tn_right->tn_system_dependent) 929 cn->tn_system_dependent = true; 930 931 return cn; 932 } 933 934 static tnode_t * 935 build_struct_access(op_t op, bool sys, tnode_t *ln, tnode_t *rn) 936 { 937 938 lint_assert(rn->tn_op == NAME); 939 lint_assert(is_member(rn->tn_sym)); 940 941 bool lvalue = op == ARROW || ln->tn_lvalue; 942 943 if (op == POINT) { 944 ln = build_address(sys, ln, true); 945 } else if (ln->tn_type->t_tspec != PTR) { 946 lint_assert(!allow_c90); 947 lint_assert(is_integer(ln->tn_type->t_tspec)); 948 ln = convert(NOOP, 0, expr_derive_type(gettyp(VOID), PTR), ln); 949 } 950 951 tnode_t *ctn = build_integer_constant(PTRDIFF_TSPEC, 952 rn->tn_sym->u.s_member.sm_offset_in_bits / CHAR_SIZE); 953 954 type_t *ptr_tp = expr_derive_type(rn->tn_type, PTR); 955 tnode_t *ntn = build_op(PLUS, sys, ptr_tp, ln, ctn); 956 if (ln->tn_op == CON) 957 ntn = fold(ntn); 958 959 op_t nop = rn->tn_type->t_bitfield ? FSEL : INDIR; 960 ntn = build_op(nop, sys, ntn->tn_type->t_subt, ntn, NULL); 961 if (!lvalue) 962 ntn->tn_lvalue = false; 963 964 return ntn; 965 } 966 967 /* 968 * Get the size in bytes of type tp->t_subt, as a constant expression of type 969 * ptrdiff_t as seen from the target platform. 970 */ 971 static tnode_t * 972 subt_size_in_bytes(type_t *tp) 973 { 974 975 lint_assert(tp->t_tspec == PTR); 976 tp = tp->t_subt; 977 978 int elem = 1; 979 while (tp->t_tspec == ARRAY) { 980 elem *= tp->t_dim; 981 tp = tp->t_subt; 982 } 983 984 int elsz_in_bits = 0; 985 switch (tp->t_tspec) { 986 case FUNC: 987 /* pointer to function is not allowed here */ 988 error(110); 989 break; 990 case VOID: 991 /* cannot do pointer arithmetic on operand of unknown size */ 992 gnuism(136); 993 break; 994 case STRUCT: 995 case UNION: 996 if ((elsz_in_bits = (int)tp->t_sou->sou_size_in_bits) == 0) 997 /* cannot do pointer arithmetic on operand of ... */ 998 error(136); 999 break; 1000 case ENUM: 1001 if (is_incomplete(tp)) { 1002 /* cannot do pointer arithmetic on operand of ... */ 1003 warning(136); 1004 } 1005 /* FALLTHROUGH */ 1006 default: 1007 if ((elsz_in_bits = size_in_bits(tp->t_tspec)) == 0) { 1008 /* cannot do pointer arithmetic on operand of ... */ 1009 error(136); 1010 } else { 1011 lint_assert(elsz_in_bits != -1); 1012 } 1013 break; 1014 } 1015 1016 if (elem == 0 && elsz_in_bits != 0) { 1017 /* cannot do pointer arithmetic on operand of unknown size */ 1018 error(136); 1019 } 1020 1021 if (elsz_in_bits == 0) 1022 elsz_in_bits = CHAR_SIZE; 1023 1024 return build_integer_constant(PTRDIFF_TSPEC, 1025 (int64_t)(elem * elsz_in_bits / CHAR_SIZE)); 1026 } 1027 1028 static tnode_t * 1029 build_prepost_incdec(op_t op, bool sys, tnode_t *ln) 1030 { 1031 1032 lint_assert(ln != NULL); 1033 tnode_t *cn = ln->tn_type->t_tspec == PTR 1034 ? subt_size_in_bytes(ln->tn_type) 1035 : build_integer_constant(INT, 1); 1036 return build_op(op, sys, ln->tn_type, ln, cn); 1037 } 1038 1039 static void 1040 check_enum_array_index(const tnode_t *ln, const tnode_t *rn) 1041 { 1042 1043 if (ln->tn_op != ADDR || ln->tn_left->tn_op != NAME) 1044 return; 1045 1046 const type_t *ltp = ln->tn_left->tn_type; 1047 if (ltp->t_tspec != ARRAY || ltp->t_incomplete_array) 1048 return; 1049 1050 if (rn->tn_op != CVT || !rn->tn_type->t_is_enum) 1051 return; 1052 if (rn->tn_left->tn_op != LOAD) 1053 return; 1054 1055 const type_t *rtp = rn->tn_left->tn_type; 1056 const sym_t *ec = rtp->t_enum->en_first_enumerator; 1057 const sym_t *max_ec = ec; 1058 lint_assert(ec != NULL); 1059 for (ec = ec->s_next; ec != NULL; ec = ec->s_next) 1060 if (ec->u.s_enum_constant > max_ec->u.s_enum_constant) 1061 max_ec = ec; 1062 1063 int64_t max_enum_value = max_ec->u.s_enum_constant; 1064 lint_assert(INT_MIN <= max_enum_value && max_enum_value <= INT_MAX); 1065 1066 int max_array_index = ltp->t_dim - 1; 1067 if (max_enum_value == max_array_index) 1068 return; 1069 1070 if (max_enum_value == max_array_index + 1 && 1071 (strstr(max_ec->s_name, "MAX") != NULL || 1072 strstr(max_ec->s_name, "max") != NULL || 1073 strstr(max_ec->s_name, "NUM") != NULL || 1074 strstr(max_ec->s_name, "num") != NULL)) 1075 return; 1076 1077 /* maximum value %d of '%s' does not match maximum array index %d */ 1078 warning(348, (int)max_enum_value, type_name(rtp), max_array_index); 1079 print_previous_declaration(max_ec); 1080 } 1081 1082 static tnode_t * 1083 build_plus_minus(op_t op, bool sys, tnode_t *ln, tnode_t *rn) 1084 { 1085 1086 if (rn->tn_type->t_tspec == PTR && is_integer(ln->tn_type->t_tspec)) { 1087 tnode_t *tmp = ln; 1088 ln = rn; 1089 rn = tmp; 1090 /* pointer addition has integer on the left-hand side */ 1091 query_message(5); 1092 } 1093 1094 /* pointer +- integer */ 1095 if (ln->tn_type->t_tspec == PTR && rn->tn_type->t_tspec != PTR) { 1096 lint_assert(is_integer(rn->tn_type->t_tspec)); 1097 1098 check_ctype_macro_invocation(ln, rn); 1099 check_enum_array_index(ln, rn); 1100 1101 tnode_t *elsz = subt_size_in_bytes(ln->tn_type); 1102 if (rn->tn_type->t_tspec != elsz->tn_type->t_tspec) 1103 rn = convert(NOOP, 0, elsz->tn_type, rn); 1104 1105 tnode_t *prod = build_op(MULT, sys, rn->tn_type, rn, elsz); 1106 if (rn->tn_op == CON) 1107 prod = fold(prod); 1108 1109 return build_op(op, sys, ln->tn_type, ln, prod); 1110 } 1111 1112 /* pointer - pointer */ 1113 if (rn->tn_type->t_tspec == PTR) { 1114 lint_assert(ln->tn_type->t_tspec == PTR); 1115 lint_assert(op == MINUS); 1116 1117 type_t *ptrdiff = gettyp(PTRDIFF_TSPEC); 1118 tnode_t *raw_diff = build_op(op, sys, ptrdiff, ln, rn); 1119 if (ln->tn_op == CON && rn->tn_op == CON) 1120 raw_diff = fold(raw_diff); 1121 1122 tnode_t *elsz = subt_size_in_bytes(ln->tn_type); 1123 balance(NOOP, &raw_diff, &elsz); 1124 1125 return build_op(DIV, sys, ptrdiff, raw_diff, elsz); 1126 } 1127 1128 return build_op(op, sys, ln->tn_type, ln, rn); 1129 } 1130 1131 static tnode_t * 1132 build_bit_shift(op_t op, bool sys, tnode_t *ln, tnode_t *rn) 1133 { 1134 1135 if (!allow_c90 && rn->tn_type->t_tspec != INT) 1136 // XXX: C1978 7.5 says: "Both [operators] perform the usual 1137 // arithmetic conversions on their operands." 1138 // TODO: Add a test to exercise this part of the code. 1139 rn = convert(NOOP, 0, gettyp(INT), rn); 1140 return build_op(op, sys, ln->tn_type, ln, rn); 1141 } 1142 1143 static bool 1144 is_null_pointer(const tnode_t *tn) 1145 { 1146 tspec_t t = tn->tn_type->t_tspec; 1147 1148 // TODO: Investigate how other pointers are stored, in particular, 1149 // whether a pointer constant can have a non-zero value. 1150 // If not, simplify the code below. 1151 return ((t == PTR && tn->tn_type->t_subt->t_tspec == VOID) 1152 || is_integer(t)) 1153 && (tn->tn_op == CON && tn->tn_val.u.integer == 0); 1154 } 1155 1156 /* Return a type based on tp1, with added qualifiers from tp2. */ 1157 static type_t * 1158 merge_qualifiers(type_t *tp1, const type_t *tp2) 1159 { 1160 1161 lint_assert(tp1->t_tspec == PTR); 1162 lint_assert(tp2->t_tspec == PTR); 1163 1164 bool c1 = tp1->t_subt->t_const; 1165 bool c2 = tp2->t_subt->t_const; 1166 bool v1 = tp1->t_subt->t_volatile; 1167 bool v2 = tp2->t_subt->t_volatile; 1168 1169 if (c1 == (c1 | c2) && v1 == (v1 | v2)) 1170 return tp1; 1171 1172 type_t *nstp = expr_dup_type(tp1->t_subt); 1173 nstp->t_const |= c2; 1174 nstp->t_volatile |= v2; 1175 1176 type_t *ntp = expr_dup_type(tp1); 1177 ntp->t_subt = nstp; 1178 return ntp; 1179 } 1180 1181 /* See C99 6.5.15 "Conditional operator". */ 1182 static tnode_t * 1183 build_colon(bool sys, tnode_t *ln, tnode_t *rn) 1184 { 1185 tspec_t lt = ln->tn_type->t_tspec; 1186 tspec_t rt = rn->tn_type->t_tspec; 1187 1188 type_t *tp; 1189 if (is_arithmetic(lt) && is_arithmetic(rt)) { 1190 /* The operands were already balanced in build_binary. */ 1191 tp = ln->tn_type; 1192 } else if (lt == BOOL && rt == BOOL) { 1193 tp = ln->tn_type; 1194 } else if (lt == VOID || rt == VOID) { 1195 tp = gettyp(VOID); 1196 } else if (is_struct_or_union(lt)) { 1197 lint_assert(is_struct_or_union(rt)); 1198 lint_assert(ln->tn_type->t_sou == rn->tn_type->t_sou); 1199 if (is_incomplete(ln->tn_type)) { 1200 /* unknown operand size, op '%s' */ 1201 error(138, op_name(COLON)); 1202 return NULL; 1203 } 1204 tp = ln->tn_type; 1205 } else if (lt == PTR && is_integer(rt)) { 1206 if (rt != PTRDIFF_TSPEC) 1207 rn = convert(NOOP, 0, gettyp(PTRDIFF_TSPEC), rn); 1208 tp = ln->tn_type; 1209 } else if (rt == PTR && is_integer(lt)) { 1210 if (lt != PTRDIFF_TSPEC) 1211 ln = convert(NOOP, 0, gettyp(PTRDIFF_TSPEC), ln); 1212 tp = rn->tn_type; 1213 } else if (lt == PTR && is_null_pointer(rn)) { 1214 tp = merge_qualifiers(ln->tn_type, rn->tn_type); 1215 } else if (rt == PTR && is_null_pointer(ln)) { 1216 tp = merge_qualifiers(rn->tn_type, ln->tn_type); 1217 } else if (lt == PTR && ln->tn_type->t_subt->t_tspec == VOID) { 1218 tp = merge_qualifiers(ln->tn_type, rn->tn_type); 1219 } else if (rt == PTR && rn->tn_type->t_subt->t_tspec == VOID) { 1220 tp = merge_qualifiers(rn->tn_type, ln->tn_type); 1221 } else { 1222 /* 1223 * XXX For now we simply take the left type. This is probably 1224 * wrong, if one type contains a function prototype and the 1225 * other one, at the same place, only an old-style declaration. 1226 */ 1227 tp = merge_qualifiers(ln->tn_type, rn->tn_type); 1228 } 1229 1230 return build_op(COLON, sys, tp, ln, rn); 1231 } 1232 1233 /* TODO: check for varargs */ 1234 static bool 1235 is_cast_redundant(const tnode_t *tn) 1236 { 1237 const type_t *ntp = tn->tn_type, *otp = tn_ck_left(tn)->tn_type; 1238 tspec_t nt = ntp->t_tspec, ot = otp->t_tspec; 1239 1240 if (nt == BOOL || ot == BOOL) 1241 return nt == BOOL && ot == BOOL; 1242 1243 if (is_integer(nt) && is_integer(ot)) { 1244 unsigned int nw = width_in_bits(ntp), ow = width_in_bits(otp); 1245 if (is_uinteger(nt) == is_uinteger(ot)) 1246 return nw >= ow; 1247 return is_uinteger(ot) && nw > ow; 1248 } 1249 1250 if (is_complex(nt) || is_complex(ot)) 1251 return is_complex(nt) && is_complex(ot) && 1252 size_in_bits(nt) >= size_in_bits(ot); 1253 1254 if (is_floating(nt) && is_floating(ot)) 1255 return size_in_bits(nt) >= size_in_bits(ot); 1256 1257 if (nt == PTR && ot == PTR) { 1258 if (!ntp->t_subt->t_const && otp->t_subt->t_const) 1259 return false; 1260 if (!ntp->t_subt->t_volatile && otp->t_subt->t_volatile) 1261 return false; 1262 1263 if (ntp->t_subt->t_tspec == VOID || 1264 otp->t_subt->t_tspec == VOID || 1265 types_compatible(ntp->t_subt, otp->t_subt, 1266 false, false, NULL)) 1267 return true; 1268 } 1269 1270 return false; 1271 } 1272 1273 static bool 1274 is_assignment(op_t op) 1275 { 1276 1277 return op == ASSIGN || 1278 op == MULASS || 1279 op == DIVASS || 1280 op == MODASS || 1281 op == ADDASS || 1282 op == SUBASS || 1283 op == SHLASS || 1284 op == SHRASS || 1285 op == ANDASS || 1286 op == XORASS || 1287 op == ORASS || 1288 op == RETURN || 1289 op == INIT; 1290 } 1291 1292 static tnode_t * 1293 build_assignment(op_t op, bool sys, tnode_t *ln, tnode_t *rn) 1294 { 1295 1296 tspec_t lt = ln->tn_type->t_tspec; 1297 tspec_t rt = rn->tn_type->t_tspec; 1298 1299 if (any_query_enabled && is_assignment(rn->tn_op)) { 1300 /* chained assignment with '%s' and '%s' */ 1301 query_message(10, op_name(op), op_name(rn->tn_op)); 1302 } 1303 1304 if ((op == ADDASS || op == SUBASS) && lt == PTR) { 1305 lint_assert(is_integer(rt)); 1306 tnode_t *ctn = subt_size_in_bytes(ln->tn_type); 1307 if (rn->tn_type->t_tspec != ctn->tn_type->t_tspec) 1308 rn = convert(NOOP, 0, ctn->tn_type, rn); 1309 rn = build_op(MULT, sys, rn->tn_type, rn, ctn); 1310 if (rn->tn_left->tn_op == CON) 1311 rn = fold(rn); 1312 } 1313 1314 if ((op == ASSIGN || op == RETURN || op == INIT) && 1315 (lt == STRUCT || rt == STRUCT)) { 1316 lint_assert(lt == rt); 1317 lint_assert(ln->tn_type->t_sou == rn->tn_type->t_sou); 1318 if (is_incomplete(ln->tn_type)) { 1319 if (op == RETURN) { 1320 /* cannot return incomplete type */ 1321 error(212); 1322 } else { 1323 /* unknown operand size, op '%s' */ 1324 error(138, op_name(op)); 1325 } 1326 return NULL; 1327 } 1328 } 1329 1330 if (op == SHLASS && hflag && allow_trad && allow_c90 1331 && portable_rank_cmp(lt, rt) < 0) 1332 /* semantics of '%s' change in C90; ... */ 1333 warning(118, "<<="); 1334 1335 if (op != SHLASS && op != SHRASS 1336 && (op == ASSIGN || lt != PTR) 1337 && (lt != rt || (ln->tn_type->t_bitfield && rn->tn_op == CON))) { 1338 rn = convert(op, 0, ln->tn_type, rn); 1339 rt = lt; 1340 } 1341 1342 if (any_query_enabled && rn->tn_op == CVT && rn->tn_cast && 1343 types_compatible(ln->tn_type, rn->tn_type, false, false, NULL) && 1344 is_cast_redundant(rn)) { 1345 /* redundant cast from '%s' to '%s' before assignment */ 1346 query_message(7, 1347 type_name(rn->tn_left->tn_type), type_name(rn->tn_type)); 1348 } 1349 1350 return build_op(op, sys, ln->tn_type, ln, rn); 1351 } 1352 1353 static tnode_t * 1354 build_real_imag(op_t op, bool sys, tnode_t *ln) 1355 { 1356 1357 lint_assert(ln != NULL); 1358 if (ln->tn_op == NAME) { 1359 /* 1360 * This may be too much, but it avoids wrong warnings. See 1361 * d_c99_complex_split.c. 1362 */ 1363 mark_as_used(ln->tn_sym, false, false); 1364 mark_as_set(ln->tn_sym); 1365 } 1366 1367 tspec_t t; 1368 switch (ln->tn_type->t_tspec) { 1369 case LCOMPLEX: 1370 t = LDOUBLE; 1371 break; 1372 case DCOMPLEX: 1373 t = DOUBLE; 1374 break; 1375 case FCOMPLEX: 1376 t = FLOAT; 1377 break; 1378 default: 1379 /* '__%s__' is illegal for type '%s' */ 1380 error(276, op == REAL ? "real" : "imag", 1381 type_name(ln->tn_type)); 1382 return NULL; 1383 } 1384 1385 tnode_t *ntn = build_op(op, sys, gettyp(t), ln, NULL); 1386 ntn->tn_lvalue = true; 1387 return ntn; 1388 } 1389 1390 static bool 1391 is_confusing_precedence(op_t op, op_t lop, bool lparen, op_t rop, bool rparen) 1392 { 1393 1394 if (op == SHL || op == SHR) { 1395 if (!lparen && (lop == PLUS || lop == MINUS)) 1396 return true; 1397 if (!rparen && (rop == PLUS || rop == MINUS)) 1398 return true; 1399 return false; 1400 } 1401 1402 if (op == LOGOR) { 1403 if (!lparen && lop == LOGAND) 1404 return true; 1405 if (!rparen && rop == LOGAND) 1406 return true; 1407 return false; 1408 } 1409 1410 lint_assert(op == BITAND || op == BITXOR || op == BITOR); 1411 if (!lparen && lop != op) { 1412 if (lop == PLUS || lop == MINUS) 1413 return true; 1414 if (lop == BITAND || lop == BITXOR) 1415 return true; 1416 } 1417 if (!rparen && rop != op) { 1418 if (rop == PLUS || rop == MINUS) 1419 return true; 1420 if (rop == BITAND || rop == BITXOR) 1421 return true; 1422 } 1423 return false; 1424 } 1425 1426 /* 1427 * Print a warning if the given node has operands which should be 1428 * parenthesized. 1429 * 1430 * XXX Does not work if an operand is a constant expression. Constant 1431 * expressions are already folded. 1432 */ 1433 static void 1434 check_precedence_confusion(tnode_t *tn) 1435 { 1436 tnode_t *ln, *rn; 1437 1438 if (!hflag) 1439 return; 1440 1441 debug_node(tn); 1442 1443 lint_assert(is_binary(tn)); 1444 for (ln = tn->tn_left; ln->tn_op == CVT; ln = ln->tn_left) 1445 continue; 1446 for (rn = tn->tn_right; rn->tn_op == CVT; rn = rn->tn_left) 1447 continue; 1448 1449 if (is_confusing_precedence(tn->tn_op, 1450 ln->tn_op, ln->tn_parenthesized, 1451 rn->tn_op, rn->tn_parenthesized)) { 1452 /* precedence confusion possible: parenthesize! */ 1453 warning(169); 1454 } 1455 } 1456 1457 /* 1458 * Fold constant nodes, as much as is needed for comparing the value with 0. 1459 */ 1460 static tnode_t * 1461 fold_bool(tnode_t *tn) 1462 { 1463 1464 val_t *v = xcalloc(1, sizeof(*v)); 1465 v->v_tspec = tn->tn_type->t_tspec; 1466 lint_assert(v->v_tspec == INT || (Tflag && v->v_tspec == BOOL)); 1467 1468 lint_assert(has_operands(tn)); 1469 bool l = constant_is_nonzero(tn->tn_left); 1470 bool r = is_binary(tn) && constant_is_nonzero(tn->tn_right); 1471 1472 switch (tn->tn_op) { 1473 case NOT: 1474 if (hflag && !suppress_constcond) 1475 /* constant operand to '!' */ 1476 warning(239); 1477 v->u.integer = !l ? 1 : 0; 1478 break; 1479 case LOGAND: 1480 v->u.integer = l && r ? 1 : 0; 1481 break; 1482 case LOGOR: 1483 v->u.integer = l || r ? 1 : 0; 1484 break; 1485 default: 1486 lint_assert(/*CONSTCOND*/false); 1487 } 1488 1489 return build_constant(tn->tn_type, v); 1490 } 1491 1492 static long double 1493 floating_error_value(tspec_t t, long double lv) 1494 { 1495 if (t == FLOAT) 1496 return lv < 0 ? -FLT_MAX : FLT_MAX; 1497 if (t == DOUBLE) 1498 return lv < 0 ? -DBL_MAX : DBL_MAX; 1499 /* 1500 * When NetBSD is cross-built in MKLINT=yes mode on x86_64 for sparc64, 1501 * tools/lint checks this code while building usr.bin/xlint. In that 1502 * situation, lint uses the preprocessor for sparc64, in which the type 1503 * 'long double' is IEEE-754-binary128, affecting the macro LDBL_MAX 1504 * below. The type 'long double', as well as the strtold 1505 * implementation, comes from the host platform x86_64 though, where 1506 * 'long double' consumes 128 bits as well but only uses 80 of them. 1507 * The exponent range of the two 'long double' types is the same, but 1508 * the maximum finite value differs due to the extended precision on 1509 * sparc64. 1510 * 1511 * To properly handle the data types of the target platform, lint would 1512 * have to implement the floating-point types in a platform-independent 1513 * way, which is not worth the effort, given how few programs 1514 * practically use 'long double'. 1515 */ 1516 /* LINTED 248: floating-point constant out of range */ 1517 long double max = LDBL_MAX; 1518 return lv < 0 ? -max : max; 1519 } 1520 1521 static bool 1522 is_floating_overflow(tspec_t t, long double val) 1523 { 1524 if (fpe != 0 || isfinite(val) == 0) 1525 return true; 1526 if (t == FLOAT && (val > FLT_MAX || val < -FLT_MAX)) 1527 return true; 1528 if (t == DOUBLE && (val > DBL_MAX || val < -DBL_MAX)) 1529 return true; 1530 return false; 1531 } 1532 1533 /* 1534 * Fold constant nodes having operands with floating point type. 1535 */ 1536 static tnode_t * 1537 fold_float(tnode_t *tn) 1538 { 1539 1540 fpe = 0; 1541 1542 tspec_t t = tn->tn_type->t_tspec; 1543 1544 val_t *v = xcalloc(1, sizeof(*v)); 1545 v->v_tspec = t; 1546 1547 lint_assert(is_floating(t)); 1548 lint_assert(has_operands(tn)); 1549 lint_assert(t == tn->tn_left->tn_type->t_tspec); 1550 lint_assert(!is_binary(tn) || t == tn->tn_right->tn_type->t_tspec); 1551 1552 long double lv = tn->tn_left->tn_val.u.floating; 1553 long double rv = is_binary(tn) ? tn->tn_right->tn_val.u.floating : 0.0; 1554 1555 switch (tn->tn_op) { 1556 case UPLUS: 1557 v->u.floating = lv; 1558 break; 1559 case UMINUS: 1560 v->u.floating = -lv; 1561 break; 1562 case MULT: 1563 v->u.floating = lv * rv; 1564 break; 1565 case DIV: 1566 if (rv == 0.0) { 1567 /* division by 0 */ 1568 error(139); 1569 v->u.floating = floating_error_value(t, lv); 1570 } else { 1571 v->u.floating = lv / rv; 1572 } 1573 break; 1574 case PLUS: 1575 v->u.floating = lv + rv; 1576 break; 1577 case MINUS: 1578 v->u.floating = lv - rv; 1579 break; 1580 case LT: 1581 v->u.integer = lv < rv ? 1 : 0; 1582 break; 1583 case LE: 1584 v->u.integer = lv <= rv ? 1 : 0; 1585 break; 1586 case GE: 1587 v->u.integer = lv >= rv ? 1 : 0; 1588 break; 1589 case GT: 1590 v->u.integer = lv > rv ? 1 : 0; 1591 break; 1592 case EQ: 1593 v->u.integer = lv == rv ? 1 : 0; 1594 break; 1595 case NE: 1596 v->u.integer = lv != rv ? 1 : 0; 1597 break; 1598 default: 1599 lint_assert(/*CONSTCOND*/false); 1600 } 1601 1602 // XXX: Must not access u.floating after setting u.integer. 1603 lint_assert(fpe != 0 || isnan(v->u.floating) == 0); 1604 if (is_complex(v->v_tspec)) { 1605 /* 1606 * Don't warn, as lint doesn't model the imaginary part of 1607 * complex numbers. 1608 */ 1609 fpe = 0; 1610 } else if (is_floating_overflow(t, v->u.floating)) { 1611 /* operator '%s' produces floating point overflow */ 1612 warning(142, op_name(tn->tn_op)); 1613 v->u.floating = floating_error_value(t, v->u.floating); 1614 fpe = 0; 1615 } 1616 1617 return build_constant(tn->tn_type, v); 1618 } 1619 1620 static void 1621 use(const tnode_t *tn) 1622 { 1623 if (tn == NULL) 1624 return; 1625 switch (tn->tn_op) { 1626 case NAME: 1627 mark_as_used(tn->tn_sym, false /* XXX */, false /* XXX */); 1628 break; 1629 case CON: 1630 case STRING: 1631 break; 1632 default: 1633 lint_assert(has_operands(tn)); 1634 use(tn->tn_left); 1635 if (is_binary(tn) || tn->tn_op == PUSH) 1636 use(tn->tn_right); 1637 } 1638 } 1639 1640 /* 1641 * Create a tree node for a binary operator and its two operands. Also called 1642 * for unary operators; in that case rn is NULL. 1643 * 1644 * Function calls, sizeof and casts are handled elsewhere. 1645 */ 1646 tnode_t * 1647 build_binary(tnode_t *ln, op_t op, bool sys, tnode_t *rn) 1648 { 1649 const mod_t *mp = &modtab[op]; 1650 1651 /* If there was an error in one of the operands, return. */ 1652 if (ln == NULL || (mp->m_binary && rn == NULL)) 1653 return NULL; 1654 1655 if (mp->m_value_context || mp->m_compares_with_zero) 1656 ln = cconv(ln); 1657 if (mp->m_binary && op != ARROW && op != POINT) 1658 rn = cconv(rn); 1659 1660 /* 1661 * Print some warnings for comparisons of unsigned values with 1662 * constants lower than or equal to null. This must be done before 1663 * promote() because otherwise unsigned char and unsigned short would 1664 * be promoted to int. Types are also tested to be CHAR, which would 1665 * also become int. 1666 */ 1667 if (mp->m_comparison) 1668 check_integer_comparison(op, ln, rn); 1669 1670 if (mp->m_value_context || mp->m_compares_with_zero) 1671 ln = promote(op, false, ln); 1672 if (mp->m_binary && op != ARROW && op != POINT && 1673 op != ASSIGN && op != RETURN && op != INIT) { 1674 rn = promote(op, false, rn); 1675 } 1676 1677 if (mp->m_warn_if_left_unsigned_in_c90 && 1678 ln->tn_op == CON && ln->tn_val.v_unsigned_since_c90) { 1679 /* C90 treats constant as unsigned, op '%s' */ 1680 warning(218, op_name(op)); 1681 ln->tn_val.v_unsigned_since_c90 = false; 1682 } 1683 if (mp->m_warn_if_right_unsigned_in_c90 && 1684 rn->tn_op == CON && rn->tn_val.v_unsigned_since_c90) { 1685 /* C90 treats constant as unsigned, op '%s' */ 1686 warning(218, op_name(op)); 1687 rn->tn_val.v_unsigned_since_c90 = false; 1688 } 1689 1690 if (mp->m_balance_operands || (!allow_c90 && (op == SHL || op == SHR))) 1691 balance(op, &ln, &rn); 1692 1693 if (!typeok(op, 0, ln, rn)) 1694 return NULL; 1695 1696 tnode_t *ntn; 1697 switch (op) { 1698 case POINT: 1699 case ARROW: 1700 ntn = build_struct_access(op, sys, ln, rn); 1701 break; 1702 case INCAFT: 1703 case DECAFT: 1704 case INCBEF: 1705 case DECBEF: 1706 ntn = build_prepost_incdec(op, sys, ln); 1707 break; 1708 case ADDR: 1709 ntn = build_address(sys, ln, false); 1710 break; 1711 case INDIR: 1712 ntn = build_op(INDIR, sys, ln->tn_type->t_subt, ln, NULL); 1713 break; 1714 case PLUS: 1715 case MINUS: 1716 ntn = build_plus_minus(op, sys, ln, rn); 1717 break; 1718 case SHL: 1719 case SHR: 1720 ntn = build_bit_shift(op, sys, ln, rn); 1721 break; 1722 case COLON: 1723 ntn = build_colon(sys, ln, rn); 1724 break; 1725 case ASSIGN: 1726 case MULASS: 1727 case DIVASS: 1728 case MODASS: 1729 case ADDASS: 1730 case SUBASS: 1731 case SHLASS: 1732 case SHRASS: 1733 case ANDASS: 1734 case XORASS: 1735 case ORASS: 1736 case RETURN: 1737 case INIT: 1738 ntn = build_assignment(op, sys, ln, rn); 1739 break; 1740 case COMMA: 1741 if (any_query_enabled) { 1742 /* comma operator with types '%s' and '%s' */ 1743 query_message(12, 1744 type_name(ln->tn_type), type_name(rn->tn_type)); 1745 } 1746 /* FALLTHROUGH */ 1747 case QUEST: 1748 ntn = build_op(op, sys, rn->tn_type, ln, rn); 1749 break; 1750 case REAL: 1751 case IMAG: 1752 ntn = build_real_imag(op, sys, ln); 1753 break; 1754 default: 1755 lint_assert(mp->m_binary == (rn != NULL)); 1756 type_t *rettp = mp->m_returns_bool 1757 ? gettyp(Tflag ? BOOL : INT) : ln->tn_type; 1758 ntn = build_op(op, sys, rettp, ln, rn); 1759 break; 1760 } 1761 1762 if (ntn == NULL) 1763 return NULL; 1764 1765 if (mp->m_possible_precedence_confusion) 1766 check_precedence_confusion(ntn); 1767 1768 if (hflag && !suppress_constcond && 1769 mp->m_compares_with_zero && 1770 (ln->tn_op == CON || 1771 ((mp->m_binary && op != QUEST) && rn->tn_op == CON)) && 1772 /* XXX: rn->tn_system_dependent should be checked as well */ 1773 !ln->tn_system_dependent) { 1774 /* constant in conditional context */ 1775 warning(161); 1776 } 1777 1778 if (mp->m_fold_constant_operands) { 1779 if (ln->tn_op == CON && (!mp->m_binary || rn->tn_op == CON)) { 1780 if (mp->m_compares_with_zero) { 1781 ntn = fold_bool(ntn); 1782 } else if (is_floating(ntn->tn_type->t_tspec)) { 1783 ntn = fold_float(ntn); 1784 } else { 1785 ntn = fold(ntn); 1786 } 1787 } else if (op == QUEST && ln->tn_op == CON) { 1788 lint_assert(has_operands(rn)); 1789 use(ln->tn_val.u.integer != 0 1790 ? rn->tn_right : rn->tn_left); 1791 ntn = ln->tn_val.u.integer != 0 1792 ? rn->tn_left : rn->tn_right; 1793 } 1794 } 1795 1796 return ntn; 1797 } 1798 1799 tnode_t * 1800 build_unary(op_t op, bool sys, tnode_t *tn) 1801 { 1802 return build_binary(tn, op, sys, NULL); 1803 } 1804 1805 static bool 1806 are_members_compatible(const sym_t *a, const sym_t *b) 1807 { 1808 if (a->u.s_member.sm_offset_in_bits != b->u.s_member.sm_offset_in_bits) 1809 return false; 1810 1811 const type_t *atp = a->s_type; 1812 const type_t *btp = b->s_type; 1813 bool w = false; 1814 if (!types_compatible(atp, btp, false, false, &w) && !w) 1815 return false; 1816 if (a->s_bitfield != b->s_bitfield) 1817 return false; 1818 if (a->s_bitfield) { 1819 if (atp->t_bit_field_width != btp->t_bit_field_width) 1820 return false; 1821 if (atp->t_bit_field_offset != btp->t_bit_field_offset) 1822 return false; 1823 } 1824 return true; 1825 } 1826 1827 /* 1828 * Return whether all struct/union members with the same name have the same 1829 * type and offset. 1830 */ 1831 static bool 1832 all_members_compatible(const sym_t *msym) 1833 { 1834 for (const sym_t *csym = msym; 1835 csym != NULL; csym = csym->s_symtab_next) { 1836 if (!is_member(csym)) 1837 continue; 1838 if (strcmp(msym->s_name, csym->s_name) != 0) 1839 continue; 1840 1841 for (const sym_t *sym = csym->s_symtab_next; 1842 sym != NULL; sym = sym->s_symtab_next) { 1843 if (is_member(sym) 1844 && strcmp(csym->s_name, sym->s_name) == 0 1845 && !are_members_compatible(csym, sym)) 1846 return false; 1847 } 1848 } 1849 return true; 1850 } 1851 1852 sym_t * 1853 find_member(const struct_or_union *sou, const char *name) 1854 { 1855 for (sym_t *mem = sou->sou_first_member; 1856 mem != NULL; mem = mem->s_next) { 1857 lint_assert(is_member(mem)); 1858 lint_assert(mem->u.s_member.sm_containing_type == sou); 1859 if (strcmp(mem->s_name, name) == 0) 1860 return mem; 1861 } 1862 1863 for (sym_t *mem = sou->sou_first_member; 1864 mem != NULL; mem = mem->s_next) { 1865 if (is_struct_or_union(mem->s_type->t_tspec) 1866 && mem->s_name == unnamed) { 1867 sym_t *nested_mem = 1868 find_member(mem->s_type->t_sou, name); 1869 if (nested_mem != NULL) 1870 return nested_mem; 1871 } 1872 } 1873 return NULL; 1874 } 1875 1876 /* 1877 * Remove the member if it was unknown until now, which means 1878 * that no defined struct or union has a member with the same name. 1879 */ 1880 static void 1881 remove_unknown_member(tnode_t *tn, sym_t *msym) 1882 { 1883 /* type '%s' does not have member '%s' */ 1884 error(101, type_name(tn->tn_type), msym->s_name); 1885 rmsym(msym); 1886 msym->s_kind = FMEMBER; 1887 msym->s_scl = STRUCT_MEMBER; 1888 1889 struct_or_union *sou = expr_zero_alloc(sizeof(*sou), 1890 "struct_or_union"); 1891 sou->sou_tag = expr_zero_alloc(sizeof(*sou->sou_tag), "sym"); 1892 sou->sou_tag->s_name = unnamed; 1893 1894 msym->u.s_member.sm_containing_type = sou; 1895 /* 1896 * The member sm_offset_in_bits is not needed here since this symbol 1897 * can only be used for error reporting. 1898 */ 1899 } 1900 1901 /* 1902 * Returns a symbol which has the same name as 'msym' and is a member of the 1903 * struct or union specified by 'tn'. 1904 */ 1905 static sym_t * 1906 struct_or_union_member(tnode_t *tn, op_t op, sym_t *msym) 1907 { 1908 1909 /* Determine the tag type of which msym is expected to be a member. */ 1910 const type_t *tp = NULL; 1911 if (op == POINT && is_struct_or_union(tn->tn_type->t_tspec)) 1912 tp = tn->tn_type; 1913 if (op == ARROW && tn->tn_type->t_tspec == PTR 1914 && is_struct_or_union(tn->tn_type->t_subt->t_tspec)) 1915 tp = tn->tn_type->t_subt; 1916 struct_or_union *sou = tp != NULL ? tp->t_sou : NULL; 1917 1918 if (sou != NULL) { 1919 sym_t *nested_mem = find_member(sou, msym->s_name); 1920 if (nested_mem != NULL) 1921 return nested_mem; 1922 } 1923 1924 if (msym->s_scl == NO_SCL) { 1925 remove_unknown_member(tn, msym); 1926 return msym; 1927 } 1928 1929 bool eq = all_members_compatible(msym); 1930 1931 /* 1932 * Now handle the case in which the left operand refers really to a 1933 * struct/union, but the right operand is not member of it. 1934 */ 1935 if (sou != NULL) { 1936 if (eq && !allow_c90) { 1937 /* illegal use of member '%s' */ 1938 warning(102, msym->s_name); 1939 } else { 1940 /* illegal use of member '%s' */ 1941 error(102, msym->s_name); 1942 } 1943 return msym; 1944 } 1945 1946 if (eq) { 1947 if (op == POINT) { 1948 if (!allow_c90) { 1949 /* left operand of '.' must be struct ... */ 1950 warning(103, type_name(tn->tn_type)); 1951 } else { 1952 /* left operand of '.' must be struct ... */ 1953 error(103, type_name(tn->tn_type)); 1954 } 1955 } else { 1956 if (!allow_c90 && tn->tn_type->t_tspec == PTR) { 1957 /* left operand of '->' must be pointer ... */ 1958 warning(104, type_name(tn->tn_type)); 1959 } else { 1960 /* left operand of '->' must be pointer ... */ 1961 error(104, type_name(tn->tn_type)); 1962 } 1963 } 1964 } else { 1965 if (!allow_c90) { 1966 /* non-unique member requires struct/union %s */ 1967 error(105, op == POINT ? "object" : "pointer"); 1968 } else { 1969 /* unacceptable operand of '%s' */ 1970 error(111, op_name(op)); 1971 } 1972 } 1973 1974 return msym; 1975 } 1976 1977 tnode_t * 1978 build_member_access(tnode_t *ln, op_t op, bool sys, sbuf_t *member) 1979 { 1980 sym_t *msym; 1981 1982 if (ln == NULL) 1983 return NULL; 1984 1985 if (op == ARROW) { 1986 /* must do this before struct_or_union_member is called */ 1987 ln = cconv(ln); 1988 } 1989 msym = struct_or_union_member(ln, op, getsym(member)); 1990 return build_binary(ln, op, sys, build_name(msym, false)); 1991 } 1992 1993 /* 1994 * Perform class conversions. 1995 * 1996 * Arrays of type T are converted into pointers to type T. 1997 * Functions are converted to pointers to functions. 1998 * Lvalues are converted to rvalues. 1999 * 2000 * C99 6.3 "Conversions" 2001 * C99 6.3.2 "Other operands" 2002 * C99 6.3.2.1 "Lvalues, arrays, and function designators" 2003 */ 2004 tnode_t * 2005 cconv(tnode_t *tn) 2006 { 2007 if (tn->tn_type->t_tspec == ARRAY) { 2008 if (!tn->tn_lvalue) { 2009 /* XXX print correct operator */ 2010 /* %soperand of '%s' must be lvalue */ 2011 gnuism(114, "", op_name(ADDR)); 2012 } 2013 tn = build_op(ADDR, tn->tn_sys, 2014 expr_derive_type(tn->tn_type->t_subt, PTR), tn, NULL); 2015 } 2016 2017 if (tn->tn_type->t_tspec == FUNC) 2018 tn = build_address(tn->tn_sys, tn, true); 2019 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 = build_op(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 C90 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 'char 2054 * st[100]; st.st_mtime', assuming that the member 'st_mtime' only 2055 * 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 the 2075 * structure of which the name of the right is a member. [...] Such 2076 * 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(op_t op, const tnode_t *tn, const type_t *tp, tspec_t t) 2111 { 2112 if (t == ARRAY || t == FUNC) { 2113 /* ok, a warning comes later (in build_address()) */ 2114 } else if (!tn->tn_lvalue) { 2115 if (tn->tn_op == CVT && tn->tn_cast && 2116 tn->tn_left->tn_op == LOAD) { 2117 /* a cast does not yield an lvalue */ 2118 error(163); 2119 } 2120 /* %soperand of '%s' must be lvalue */ 2121 error(114, "", op_name(op)); 2122 return false; 2123 } else if (is_scalar(t)) { 2124 if (tp->t_bitfield) { 2125 /* cannot take address of bit-field */ 2126 error(112); 2127 return false; 2128 } 2129 } else if (t != STRUCT && t != UNION) { 2130 /* unacceptable operand of '%s' */ 2131 error(111, op_name(op)); 2132 return false; 2133 } 2134 if (tn->tn_op == NAME && tn->tn_sym->s_register) { 2135 /* cannot take address of register '%s' */ 2136 error(113, tn->tn_sym->s_name); 2137 return false; 2138 } 2139 return true; 2140 } 2141 2142 static bool 2143 typeok_indir(const type_t *tp, tspec_t t) 2144 { 2145 2146 if (t != PTR) { 2147 /* cannot dereference non-pointer type '%s' */ 2148 error(96, type_name(tp)); 2149 return false; 2150 } 2151 return true; 2152 } 2153 2154 static void 2155 warn_incompatible_types(op_t op, 2156 const type_t *ltp, tspec_t lt, 2157 const type_t *rtp, tspec_t rt) 2158 { 2159 bool binary = modtab[op].m_binary; 2160 2161 if (lt == VOID || (binary && rt == VOID)) { 2162 /* void type illegal in expression */ 2163 error(109); 2164 } else if (op == ASSIGN) { 2165 /* cannot assign to '%s' from '%s' */ 2166 error(171, type_name(ltp), type_name(rtp)); 2167 } else if (binary) { 2168 /* operands of '%s' have incompatible types '%s' and '%s' */ 2169 error(107, op_name(op), type_name(ltp), type_name(rtp)); 2170 } else { 2171 lint_assert(rt == NO_TSPEC); 2172 /* operand of '%s' has invalid type '%s' */ 2173 error(108, op_name(op), type_name(ltp)); 2174 } 2175 } 2176 2177 static bool 2178 typeok_plus(op_t op, 2179 const type_t *ltp, tspec_t lt, 2180 const type_t *rtp, tspec_t rt) 2181 { 2182 /* operands have scalar types (checked in typeok) */ 2183 if ((lt == PTR && !is_integer(rt)) || (rt == PTR && !is_integer(lt))) { 2184 warn_incompatible_types(op, ltp, lt, rtp, rt); 2185 return false; 2186 } 2187 return true; 2188 } 2189 2190 static bool 2191 typeok_minus(op_t op, 2192 const type_t *ltp, tspec_t lt, 2193 const type_t *rtp, tspec_t rt) 2194 { 2195 /* operands have scalar types (checked in typeok) */ 2196 if ((lt == PTR && rt != PTR && !is_integer(rt)) || 2197 (lt != PTR && rt == PTR)) { 2198 warn_incompatible_types(op, ltp, lt, rtp, rt); 2199 return false; 2200 } 2201 if (lt == PTR && rt == PTR && 2202 !types_compatible(ltp->t_subt, rtp->t_subt, true, false, NULL)) { 2203 /* illegal pointer subtraction */ 2204 error(116); 2205 } 2206 return true; 2207 } 2208 2209 static void 2210 typeok_shr(op_t op, 2211 const tnode_t *ln, tspec_t lt, 2212 const tnode_t *rn, tspec_t rt) 2213 { 2214 tspec_t olt = before_conversion(ln)->tn_type->t_tspec; 2215 tspec_t ort = before_conversion(rn)->tn_type->t_tspec; 2216 2217 /* operands have integer types (checked in typeok) */ 2218 if (pflag && !is_uinteger(olt)) { 2219 integer_constraints lc = ic_expr(ln); 2220 if (!ic_maybe_signed(ln->tn_type, &lc)) 2221 return; 2222 2223 if (ln->tn_op != CON) { 2224 /* bitwise '%s' on signed value possibly nonportable */ 2225 warning(117, op_name(op)); 2226 } else if (ln->tn_val.u.integer < 0) { 2227 /* bitwise '%s' on signed value nonportable */ 2228 warning(120, op_name(op)); 2229 } 2230 } else if (allow_trad && allow_c90 && 2231 !is_uinteger(olt) && is_uinteger(ort)) { 2232 /* The left operand would become unsigned in traditional C. */ 2233 if (hflag && (ln->tn_op != CON || ln->tn_val.u.integer < 0)) { 2234 /* semantics of '%s' change in C90; use ... */ 2235 warning(118, op_name(op)); 2236 } 2237 } else if (allow_trad && allow_c90 && 2238 !is_uinteger(olt) && !is_uinteger(ort) && 2239 portable_rank_cmp(lt, rt) < 0) { 2240 /* 2241 * In traditional C, the left operand would be extended 2242 * (possibly sign-extended) and then shifted. 2243 */ 2244 if (hflag && (ln->tn_op != CON || ln->tn_val.u.integer < 0)) { 2245 /* semantics of '%s' change in C90; use ... */ 2246 warning(118, op_name(op)); 2247 } 2248 } 2249 } 2250 2251 static void 2252 typeok_shl(op_t op, tspec_t lt, tspec_t rt) 2253 { 2254 /* 2255 * C90 does not perform balancing for shift operations, but traditional 2256 * C does. If the width of the right operand is greater than the width 2257 * of the left operand, then in traditional C the left operand would be 2258 * extended to the width of the right operand. For SHL this may result 2259 * in different results. 2260 */ 2261 if (portable_rank_cmp(lt, rt) < 0) { 2262 /* 2263 * XXX If both operands are constant, make sure that there is 2264 * really a difference between C90 and traditional C. 2265 */ 2266 if (hflag && allow_trad && allow_c90) 2267 /* semantics of '%s' change in C90; use ... */ 2268 warning(118, op_name(op)); 2269 } 2270 } 2271 2272 static void 2273 typeok_shift(const type_t *ltp, tspec_t lt, const tnode_t *rn, tspec_t rt) 2274 { 2275 if (rn->tn_op != CON) 2276 return; 2277 2278 if (!is_uinteger(rt) && rn->tn_val.u.integer < 0) { 2279 /* negative shift */ 2280 warning(121); 2281 } else if ((uint64_t)rn->tn_val.u.integer == size_in_bits(lt)) { 2282 /* shift amount %u equals bit-size of '%s' */ 2283 warning(267, (unsigned)rn->tn_val.u.integer, type_name(ltp)); 2284 } else if ((uint64_t)rn->tn_val.u.integer > size_in_bits(lt)) { 2285 /* shift amount %llu is greater than bit-size %llu of '%s' */ 2286 warning(122, (unsigned long long)rn->tn_val.u.integer, 2287 (unsigned long long)size_in_bits(lt), 2288 tspec_name(lt)); 2289 } 2290 } 2291 2292 static bool 2293 is_typeok_eq(const tnode_t *ln, tspec_t lt, const tnode_t *rn, tspec_t rt) 2294 { 2295 if (lt == PTR && is_null_pointer(rn)) 2296 return true; 2297 if (rt == PTR && is_null_pointer(ln)) 2298 return true; 2299 return false; 2300 } 2301 2302 static void 2303 warn_incompatible_pointers(op_t op, const type_t *ltp, const type_t *rtp) 2304 { 2305 lint_assert(ltp->t_tspec == PTR); 2306 lint_assert(rtp->t_tspec == PTR); 2307 2308 tspec_t lt = ltp->t_subt->t_tspec; 2309 tspec_t rt = rtp->t_subt->t_tspec; 2310 2311 if (is_struct_or_union(lt) && is_struct_or_union(rt)) { 2312 if (op == RETURN) { 2313 /* illegal structure pointer combination */ 2314 warning(244); 2315 } else { 2316 /* incompatible structure pointers: '%s' '%s' '%s' */ 2317 warning(245, type_name(ltp), 2318 op_name(op), type_name(rtp)); 2319 } 2320 } else { 2321 if (op == RETURN) { 2322 /* illegal combination of '%s' and '%s' */ 2323 warning(184, type_name(ltp), type_name(rtp)); 2324 } else { 2325 /* illegal combination of '%s' and '%s', op '%s' */ 2326 warning(124, 2327 type_name(ltp), type_name(rtp), op_name(op)); 2328 } 2329 } 2330 } 2331 2332 static void 2333 check_pointer_comparison(op_t op, const tnode_t *ln, const tnode_t *rn) 2334 { 2335 type_t *ltp = ln->tn_type, *rtp = rn->tn_type; 2336 tspec_t lst = ltp->t_subt->t_tspec, rst = rtp->t_subt->t_tspec; 2337 2338 if (lst == VOID || rst == VOID) { 2339 /* TODO: C99 behaves like C90 here. */ 2340 if ((!allow_trad && !allow_c99) && 2341 (lst == FUNC || rst == FUNC)) { 2342 /* (void *)0 is already handled in typeok() */ 2343 const char *lsts, *rsts; 2344 *(lst == FUNC ? &lsts : &rsts) = "function pointer"; 2345 *(lst == VOID ? &lsts : &rsts) = "'void *'"; 2346 /* C90 or later forbid comparison of %s with %s */ 2347 warning(274, lsts, rsts); 2348 } 2349 return; 2350 } 2351 2352 if (!types_compatible(ltp->t_subt, rtp->t_subt, true, false, NULL)) { 2353 warn_incompatible_pointers(op, ltp, rtp); 2354 return; 2355 } 2356 2357 if (lst == FUNC && rst == FUNC) { 2358 /* TODO: C99 behaves like C90 here, see C99 6.5.8p2. */ 2359 if ((!allow_trad && !allow_c99) && op != EQ && op != NE) 2360 /* pointers to functions can only be compared ... */ 2361 warning(125); 2362 } 2363 } 2364 2365 static bool 2366 typeok_compare(op_t op, 2367 const tnode_t *ln, const type_t *ltp, tspec_t lt, 2368 const tnode_t *rn, const type_t *rtp, tspec_t rt) 2369 { 2370 if (lt == PTR && rt == PTR) { 2371 check_pointer_comparison(op, ln, rn); 2372 return true; 2373 } 2374 2375 if (lt != PTR && rt != PTR) 2376 return true; 2377 2378 if (!is_integer(lt) && !is_integer(rt)) { 2379 warn_incompatible_types(op, ltp, lt, rtp, rt); 2380 return false; 2381 } 2382 2383 const char *lx = lt == PTR ? "pointer" : "integer"; 2384 const char *rx = rt == PTR ? "pointer" : "integer"; 2385 /* illegal combination of %s '%s' and %s '%s', op '%s' */ 2386 warning(123, lx, type_name(ltp), rx, type_name(rtp), op_name(op)); 2387 return true; 2388 } 2389 2390 static bool 2391 typeok_quest(tspec_t lt, const tnode_t *rn) 2392 { 2393 if (!is_scalar(lt)) { 2394 /* first operand of '?' must have scalar type */ 2395 error(170); 2396 return false; 2397 } 2398 lint_assert(before_conversion(rn)->tn_op == COLON); 2399 return true; 2400 } 2401 2402 static void 2403 typeok_colon_pointer(const type_t *ltp, const type_t *rtp) 2404 { 2405 type_t *lstp = ltp->t_subt; 2406 type_t *rstp = rtp->t_subt; 2407 tspec_t lst = lstp->t_tspec; 2408 tspec_t rst = rstp->t_tspec; 2409 2410 if ((lst == VOID && rst == FUNC) || (lst == FUNC && rst == VOID)) { 2411 /* (void *)0 is handled in typeok_colon */ 2412 /* TODO: C99 behaves like C90 here. */ 2413 if (!allow_trad && !allow_c99) 2414 /* conversion of %s to %s requires a cast, op %s */ 2415 warning(305, "function pointer", "'void *'", 2416 op_name(COLON)); 2417 return; 2418 } 2419 2420 if (pointer_types_are_compatible(lstp, rstp, true)) 2421 return; 2422 if (!types_compatible(lstp, rstp, true, false, NULL)) 2423 warn_incompatible_pointers(COLON, ltp, rtp); 2424 } 2425 2426 static bool 2427 typeok_colon(const tnode_t *ln, const type_t *ltp, tspec_t lt, 2428 const tnode_t *rn, const type_t *rtp, tspec_t rt) 2429 { 2430 2431 if (is_arithmetic(lt) && is_arithmetic(rt)) 2432 return true; 2433 if (lt == BOOL && rt == BOOL) 2434 return true; 2435 2436 if (lt == STRUCT && rt == STRUCT && ltp->t_sou == rtp->t_sou) 2437 return true; 2438 if (lt == UNION && rt == UNION && ltp->t_sou == rtp->t_sou) 2439 return true; 2440 2441 if (lt == PTR && is_null_pointer(rn)) 2442 return true; 2443 if (rt == PTR && is_null_pointer(ln)) 2444 return true; 2445 2446 if ((lt == PTR && is_integer(rt)) || (is_integer(lt) && rt == PTR)) { 2447 const char *lx = lt == PTR ? "pointer" : "integer"; 2448 const char *rx = rt == PTR ? "pointer" : "integer"; 2449 /* illegal combination of %s '%s' and %s '%s', op '%s' */ 2450 warning(123, lx, type_name(ltp), 2451 rx, type_name(rtp), op_name(COLON)); 2452 return true; 2453 } 2454 2455 if (lt == VOID || rt == VOID) { 2456 if (lt != VOID || rt != VOID) 2457 /* incompatible types '%s' and '%s' in conditional */ 2458 warning(126, type_name(ltp), type_name(rtp)); 2459 return true; 2460 } 2461 2462 if (lt == PTR && rt == PTR) { 2463 typeok_colon_pointer(ltp, rtp); 2464 return true; 2465 } 2466 2467 /* incompatible types '%s' and '%s' in conditional */ 2468 error(126, type_name(ltp), type_name(rtp)); 2469 return false; 2470 } 2471 2472 static bool 2473 has_constant_member(const type_t *tp) 2474 { 2475 lint_assert(is_struct_or_union(tp->t_tspec)); 2476 2477 for (sym_t *m = tp->t_sou->sou_first_member; 2478 m != NULL; m = m->s_next) { 2479 const type_t *mtp = m->s_type; 2480 if (mtp->t_const) 2481 return true; 2482 if (is_struct_or_union(mtp->t_tspec) && 2483 has_constant_member(mtp)) 2484 return true; 2485 } 2486 return false; 2487 } 2488 2489 static bool 2490 typeok_assign(op_t op, const tnode_t *ln, const type_t *ltp, tspec_t lt) 2491 { 2492 if (op == RETURN || op == INIT || op == FARG) 2493 return true; 2494 2495 if (!ln->tn_lvalue) { 2496 if (ln->tn_op == CVT && ln->tn_cast && 2497 ln->tn_left->tn_op == LOAD) { 2498 /* a cast does not yield an lvalue */ 2499 error(163); 2500 } 2501 /* %soperand of '%s' must be lvalue */ 2502 error(114, "left ", op_name(op)); 2503 return false; 2504 } else if (ltp->t_const 2505 || (is_struct_or_union(lt) && has_constant_member(ltp))) { 2506 if (allow_c90) 2507 /* %soperand of '%s' must be modifiable lvalue */ 2508 warning(115, "left ", op_name(op)); 2509 } 2510 return true; 2511 } 2512 2513 static bool 2514 typeok_scalar(op_t op, const mod_t *mp, 2515 const type_t *ltp, tspec_t lt, 2516 const type_t *rtp, tspec_t rt) 2517 { 2518 if (mp->m_takes_bool && lt == BOOL && rt == BOOL) 2519 return true; 2520 if (mp->m_requires_integer) { 2521 if (!is_integer(lt) || (mp->m_binary && !is_integer(rt))) { 2522 warn_incompatible_types(op, ltp, lt, rtp, rt); 2523 return false; 2524 } 2525 } else if (mp->m_requires_integer_or_complex) { 2526 if ((!is_integer(lt) && !is_complex(lt)) || 2527 (mp->m_binary && (!is_integer(rt) && !is_complex(rt)))) { 2528 warn_incompatible_types(op, ltp, lt, rtp, rt); 2529 return false; 2530 } 2531 } else if (mp->m_requires_scalar) { 2532 if (!is_scalar(lt) || (mp->m_binary && !is_scalar(rt))) { 2533 warn_incompatible_types(op, ltp, lt, rtp, rt); 2534 return false; 2535 } 2536 } else if (mp->m_requires_arith) { 2537 if (!is_arithmetic(lt) || 2538 (mp->m_binary && !is_arithmetic(rt))) { 2539 warn_incompatible_types(op, ltp, lt, rtp, rt); 2540 return false; 2541 } 2542 } 2543 return true; 2544 } 2545 2546 static void 2547 check_assign_void_pointer(op_t op, int arg, 2548 tspec_t lt, tspec_t lst, 2549 tspec_t rt, tspec_t rst) 2550 { 2551 2552 if (!(lt == PTR && rt == PTR && (lst == VOID || rst == VOID))) 2553 return; 2554 /* two pointers, at least one pointer to void */ 2555 2556 /* TODO: C99 behaves like C90 here. */ 2557 if (!((!allow_trad && !allow_c99) && (lst == FUNC || rst == FUNC))) 2558 return; 2559 /* comb. of ptr to func and ptr to void */ 2560 2561 const char *lts, *rts; 2562 *(lst == FUNC ? <s : &rts) = "function pointer"; 2563 *(lst == VOID ? <s : &rts) = "'void *'"; 2564 2565 switch (op) { 2566 case INIT: 2567 case RETURN: 2568 /* conversion of %s to %s requires a cast */ 2569 warning(303, rts, lts); 2570 break; 2571 case FARG: 2572 /* conversion of %s to %s requires a cast, arg #%d */ 2573 warning(304, rts, lts, arg); 2574 break; 2575 default: 2576 /* conversion of %s to %s requires a cast, op %s */ 2577 warning(305, rts, lts, op_name(op)); 2578 break; 2579 } 2580 } 2581 2582 static bool 2583 is_direct_function_call(const tnode_t *tn, const char **out_name) 2584 { 2585 2586 if (!(tn->tn_op == CALL && 2587 tn->tn_left->tn_op == ADDR && 2588 tn->tn_left->tn_left->tn_op == NAME)) 2589 return false; 2590 2591 *out_name = tn->tn_left->tn_left->tn_sym->s_name; 2592 return true; 2593 } 2594 2595 static bool 2596 is_unconst_function(const char *name) 2597 { 2598 2599 return strcmp(name, "memchr") == 0 || 2600 strcmp(name, "strchr") == 0 || 2601 strcmp(name, "strpbrk") == 0 || 2602 strcmp(name, "strrchr") == 0 || 2603 strcmp(name, "strstr") == 0; 2604 } 2605 2606 static bool 2607 is_const_char_pointer(const tnode_t *tn) 2608 { 2609 /* 2610 * For traditional reasons, C99 6.4.5p5 defines that string literals 2611 * have type 'char[]'. They are often implicitly converted to 'char 2612 * *', for example when they are passed as function arguments. 2613 * 2614 * C99 6.4.5p6 further defines that modifying a string that is 2615 * constructed from a string literal invokes undefined behavior. 2616 * 2617 * Out of these reasons, string literals are treated as 'effectively 2618 * const' here. 2619 */ 2620 if (tn->tn_op == CVT && 2621 tn->tn_left->tn_op == ADDR && 2622 tn->tn_left->tn_left->tn_op == STRING) 2623 return true; 2624 2625 const type_t *tp = before_conversion(tn)->tn_type; 2626 return tp->t_tspec == PTR && 2627 tp->t_subt->t_tspec == CHAR && 2628 tp->t_subt->t_const; 2629 } 2630 2631 static bool 2632 is_first_arg_const_char_pointer(const tnode_t *tn) 2633 { 2634 lint_assert(has_operands(tn)); 2635 const tnode_t *an = tn->tn_right; 2636 if (an == NULL) 2637 return false; 2638 2639 while (tn_ck_right(an) != NULL) 2640 an = an->tn_right; 2641 return is_const_char_pointer(an->tn_left); 2642 } 2643 2644 static bool 2645 is_const_pointer(const tnode_t *tn) 2646 { 2647 const type_t *tp = before_conversion(tn)->tn_type; 2648 return tp->t_tspec == PTR && tp->t_subt->t_const; 2649 } 2650 2651 static bool 2652 is_second_arg_const_pointer(const tnode_t *tn) 2653 { 2654 const tnode_t *an = tn_ck_right(tn); 2655 if (an == NULL || tn_ck_right(an) == NULL) 2656 return false; 2657 2658 while (tn_ck_right(an->tn_right) != NULL) 2659 an = an->tn_right; 2660 return is_const_pointer(an->tn_left); 2661 } 2662 2663 static void 2664 check_unconst_function(const type_t *lstp, const tnode_t *rn) 2665 { 2666 const char *function_name; 2667 2668 if (lstp->t_tspec == CHAR && !lstp->t_const && 2669 is_direct_function_call(rn, &function_name) && 2670 is_unconst_function(function_name) && 2671 is_first_arg_const_char_pointer(rn)) { 2672 /* call to '%s' effectively discards 'const' from argument */ 2673 warning(346, function_name); 2674 } 2675 2676 if (!lstp->t_const && 2677 is_direct_function_call(rn, &function_name) && 2678 strcmp(function_name, "bsearch") == 0 && 2679 is_second_arg_const_pointer(rn)) { 2680 /* call to '%s' effectively discards 'const' from argument */ 2681 warning(346, function_name); 2682 } 2683 } 2684 2685 static bool 2686 check_assign_void_pointer_compat(op_t op, int arg, 2687 const type_t *const ltp, tspec_t const lt, 2688 const type_t *const lstp, tspec_t const lst, 2689 const tnode_t *const rn, 2690 const type_t *const rtp, tspec_t const rt, 2691 const type_t *const rstp, tspec_t const rst) 2692 { 2693 if (!(lt == PTR && rt == PTR && (lst == VOID || rst == VOID || 2694 types_compatible(lstp, rstp, 2695 true, false, NULL)))) 2696 return false; 2697 2698 /* compatible pointer types (qualifiers ignored) */ 2699 if (allow_c90 && 2700 ((!lstp->t_const && rstp->t_const) || 2701 (!lstp->t_volatile && rstp->t_volatile))) { 2702 /* left side has not all qualifiers of right */ 2703 switch (op) { 2704 case INIT: 2705 case RETURN: 2706 /* incompatible pointer types to '%s' and '%s' */ 2707 warning(182, type_name(lstp), type_name(rstp)); 2708 break; 2709 case FARG: 2710 /* converting '%s' to incompatible '%s' ... */ 2711 warning(153, 2712 type_name(rtp), type_name(ltp), arg); 2713 break; 2714 default: 2715 /* operands of '%s' have incompatible pointer ... */ 2716 warning(128, op_name(op), 2717 type_name(lstp), type_name(rstp)); 2718 break; 2719 } 2720 } 2721 2722 if (allow_c90) 2723 check_unconst_function(lstp, rn); 2724 2725 return true; 2726 } 2727 2728 static bool 2729 check_assign_pointer_integer(op_t op, int arg, 2730 const type_t *const ltp, tspec_t const lt, 2731 const type_t *const rtp, tspec_t const rt) 2732 { 2733 2734 if (!((lt == PTR && is_integer(rt)) || (is_integer(lt) && rt == PTR))) 2735 return false; 2736 2737 const char *lx = lt == PTR ? "pointer" : "integer"; 2738 const char *rx = rt == PTR ? "pointer" : "integer"; 2739 2740 switch (op) { 2741 case INIT: 2742 case RETURN: 2743 /* illegal combination of %s '%s' and %s '%s' */ 2744 warning(183, lx, type_name(ltp), rx, type_name(rtp)); 2745 break; 2746 case FARG: 2747 /* illegal combination of %s '%s' and %s '%s', arg #%d */ 2748 warning(154, 2749 lx, type_name(ltp), rx, type_name(rtp), arg); 2750 break; 2751 default: 2752 /* illegal combination of %s '%s' and %s '%s', op '%s' */ 2753 warning(123, 2754 lx, type_name(ltp), rx, type_name(rtp), op_name(op)); 2755 break; 2756 } 2757 return true; 2758 } 2759 2760 static bool 2761 check_assign_pointer(op_t op, int arg, 2762 const type_t *ltp, tspec_t lt, 2763 const type_t *rtp, tspec_t rt) 2764 { 2765 if (!(lt == PTR && rt == PTR)) 2766 return false; 2767 2768 if (op == FARG) 2769 /* converting '%s' to incompatible '%s' for ... */ 2770 warning(153, type_name(rtp), type_name(ltp), arg); 2771 else 2772 warn_incompatible_pointers(op, ltp, rtp); 2773 return true; 2774 } 2775 2776 static void 2777 warn_assign(op_t op, int arg, 2778 const type_t *ltp, tspec_t lt, 2779 const type_t *rtp, tspec_t rt) 2780 { 2781 switch (op) { 2782 case INIT: 2783 /* cannot initialize '%s' from '%s' */ 2784 error(185, type_name(ltp), type_name(rtp)); 2785 break; 2786 case RETURN: 2787 /* function has return type '%s' but returns '%s' */ 2788 error(211, type_name(ltp), type_name(rtp)); 2789 break; 2790 case FARG: 2791 /* passing '%s' to incompatible '%s', arg #%d */ 2792 warning(155, type_name(rtp), type_name(ltp), arg); 2793 break; 2794 default: 2795 warn_incompatible_types(op, ltp, lt, rtp, rt); 2796 break; 2797 } 2798 } 2799 2800 /* 2801 * Checks type compatibility for ASSIGN, INIT, FARG and RETURN 2802 * and prints warnings/errors if necessary. 2803 * Returns whether the types are (almost) compatible. 2804 */ 2805 static bool 2806 check_assign_types_compatible(op_t op, int arg, 2807 const tnode_t *ln, const tnode_t *rn) 2808 { 2809 tspec_t lt, rt, lst = NO_TSPEC, rst = NO_TSPEC; 2810 type_t *ltp, *rtp, *lstp = NULL, *rstp = NULL; 2811 2812 if ((lt = (ltp = ln->tn_type)->t_tspec) == PTR) 2813 lst = (lstp = ltp->t_subt)->t_tspec; 2814 if ((rt = (rtp = rn->tn_type)->t_tspec) == PTR) 2815 rst = (rstp = rtp->t_subt)->t_tspec; 2816 2817 if (lt == BOOL && is_scalar(rt)) /* C99 6.3.1.2 */ 2818 return true; 2819 2820 if (is_arithmetic(lt) && (is_arithmetic(rt) || rt == BOOL)) 2821 return true; 2822 2823 if (is_struct_or_union(lt) && is_struct_or_union(rt)) 2824 return ltp->t_sou == rtp->t_sou; 2825 2826 if (lt == PTR && is_null_pointer(rn)) { 2827 if (is_integer(rn->tn_type->t_tspec)) 2828 /* implicit conversion from integer 0 to pointer ... */ 2829 query_message(15, type_name(ltp)); 2830 return true; 2831 } 2832 2833 check_assign_void_pointer(op, arg, lt, lst, rt, rst); 2834 2835 if (check_assign_void_pointer_compat(op, arg, 2836 ltp, lt, lstp, lst, rn, rtp, rt, rstp, rst)) 2837 return true; 2838 2839 if (check_assign_pointer_integer(op, arg, ltp, lt, rtp, rt)) 2840 return true; 2841 2842 if (check_assign_pointer(op, arg, ltp, lt, rtp, rt)) 2843 return true; 2844 2845 warn_assign(op, arg, ltp, lt, rtp, rt); 2846 return false; 2847 } 2848 2849 static bool 2850 has_side_effect(const tnode_t *tn) /* NOLINT(misc-no-recursion) */ 2851 { 2852 op_t op = tn->tn_op; 2853 2854 if (modtab[op].m_has_side_effect) 2855 return true; 2856 2857 if (op == CVT && tn->tn_type->t_tspec == VOID) 2858 return has_side_effect(tn->tn_left); 2859 2860 /* XXX: Why not has_side_effect(tn->tn_left) as well? */ 2861 if (op == LOGAND || op == LOGOR) 2862 return has_side_effect(tn->tn_right); 2863 2864 /* XXX: Why not has_side_effect(tn->tn_left) as well? */ 2865 if (op == QUEST) 2866 return has_side_effect(tn->tn_right); 2867 2868 if (op == COLON || op == COMMA) { 2869 return has_side_effect(tn->tn_left) || 2870 has_side_effect(tn->tn_right); 2871 } 2872 2873 return false; 2874 } 2875 2876 static bool 2877 is_void_cast(const tnode_t *tn) 2878 { 2879 2880 return tn->tn_op == CVT && tn->tn_cast && 2881 tn->tn_type->t_tspec == VOID; 2882 } 2883 2884 static bool 2885 is_local_symbol(const tnode_t *tn) 2886 { 2887 2888 return tn->tn_op == LOAD && 2889 tn->tn_left->tn_op == NAME && 2890 tn->tn_left->tn_sym->s_scl == AUTO; 2891 } 2892 2893 static bool 2894 is_int_constant_zero(const tnode_t *tn) 2895 { 2896 2897 return tn->tn_op == CON && 2898 tn->tn_type->t_tspec == INT && 2899 tn->tn_val.u.integer == 0; 2900 } 2901 2902 static void 2903 check_null_effect(const tnode_t *tn) 2904 { 2905 2906 if (hflag && 2907 !has_side_effect(tn) && 2908 !(is_void_cast(tn) && is_local_symbol(tn->tn_left)) && 2909 !(is_void_cast(tn) && is_int_constant_zero(tn->tn_left))) { 2910 /* expression has null effect */ 2911 warning(129); 2912 } 2913 } 2914 2915 /* 2916 * Check the types for specific operators and type combinations. 2917 * 2918 * At this point, the operands already conform to the type requirements of 2919 * the operator, such as being integer, floating or scalar. 2920 */ 2921 static bool 2922 typeok_op(op_t op, int arg, 2923 const tnode_t *ln, const type_t *ltp, tspec_t lt, 2924 const tnode_t *rn, const type_t *rtp, tspec_t rt) 2925 { 2926 switch (op) { 2927 case ARROW: 2928 return typeok_arrow(lt); 2929 case POINT: 2930 return typeok_point(ln, ltp, lt); 2931 case INCBEF: 2932 case DECBEF: 2933 case INCAFT: 2934 case DECAFT: 2935 return typeok_incdec(op, ln, ltp); 2936 case INDIR: 2937 return typeok_indir(ltp, lt); 2938 case ADDR: 2939 return typeok_address(op, ln, ltp, lt); 2940 case PLUS: 2941 return typeok_plus(op, ltp, lt, rtp, rt); 2942 case MINUS: 2943 return typeok_minus(op, ltp, lt, rtp, rt); 2944 case SHL: 2945 typeok_shl(op, lt, rt); 2946 goto shift; 2947 case SHR: 2948 typeok_shr(op, ln, lt, rn, rt); 2949 shift: 2950 typeok_shift(ltp, lt, rn, rt); 2951 break; 2952 case LT: 2953 case LE: 2954 case GT: 2955 case GE: 2956 compare: 2957 return typeok_compare(op, ln, ltp, lt, rn, rtp, rt); 2958 case EQ: 2959 case NE: 2960 if (is_typeok_eq(ln, lt, rn, rt)) 2961 break; 2962 goto compare; 2963 case QUEST: 2964 return typeok_quest(lt, rn); 2965 case COLON: 2966 return typeok_colon(ln, ltp, lt, rn, rtp, rt); 2967 case ASSIGN: 2968 case INIT: 2969 case FARG: 2970 case RETURN: 2971 if (!check_assign_types_compatible(op, arg, ln, rn)) 2972 return false; 2973 goto assign; 2974 case MULASS: 2975 case DIVASS: 2976 case MODASS: 2977 goto assign; 2978 case ADDASS: 2979 case SUBASS: 2980 if ((lt == PTR && !is_integer(rt)) || rt == PTR) { 2981 warn_incompatible_types(op, ltp, lt, rtp, rt); 2982 return false; 2983 } 2984 goto assign; 2985 case SHLASS: 2986 goto assign; 2987 case SHRASS: 2988 if (pflag && !is_uinteger(lt) && 2989 !(!allow_c90 && is_uinteger(rt))) { 2990 /* bitwise '%s' on signed value possibly nonportable */ 2991 warning(117, op_name(op)); 2992 } 2993 goto assign; 2994 case ANDASS: 2995 case XORASS: 2996 case ORASS: 2997 assign: 2998 return typeok_assign(op, ln, ltp, lt); 2999 case COMMA: 3000 if (!modtab[ln->tn_op].m_has_side_effect) 3001 check_null_effect(ln); 3002 break; 3003 default: 3004 break; 3005 } 3006 return true; 3007 } 3008 3009 static void 3010 check_bad_enum_operation(op_t op, const tnode_t *ln, const tnode_t *rn) 3011 { 3012 3013 if (!eflag) 3014 return; 3015 3016 /* Allow enum in array indices. */ 3017 if (op == PLUS && 3018 ((ln->tn_type->t_is_enum && rn->tn_type->t_tspec == PTR) || 3019 (rn->tn_type->t_is_enum && ln->tn_type->t_tspec == PTR))) { 3020 return; 3021 } 3022 3023 /* dubious operation '%s' on enum */ 3024 warning(241, op_name(op)); 3025 } 3026 3027 static void 3028 check_enum_type_mismatch(op_t op, int arg, const tnode_t *ln, const tnode_t *rn) 3029 { 3030 const mod_t *mp = &modtab[op]; 3031 3032 if (ln->tn_type->t_enum != rn->tn_type->t_enum) { 3033 switch (op) { 3034 case INIT: 3035 /* enum type mismatch between '%s' and '%s' in ... */ 3036 warning(210, 3037 type_name(ln->tn_type), type_name(rn->tn_type)); 3038 break; 3039 case FARG: 3040 /* function expects '%s', passing '%s' for arg #%d */ 3041 warning(156, 3042 type_name(ln->tn_type), type_name(rn->tn_type), 3043 arg); 3044 break; 3045 case RETURN: 3046 /* function has return type '%s' but returns '%s' */ 3047 warning(211, 3048 type_name(ln->tn_type), type_name(rn->tn_type)); 3049 break; 3050 default: 3051 /* enum type mismatch: '%s' '%s' '%s' */ 3052 warning(130, type_name(ln->tn_type), op_name(op), 3053 type_name(rn->tn_type)); 3054 break; 3055 } 3056 } else if (Pflag && eflag && mp->m_comparison && op != EQ && op != NE) 3057 /* operator '%s' assumes that '%s' is ordered */ 3058 warning(243, op_name(op), type_name(ln->tn_type)); 3059 } 3060 3061 static void 3062 check_enum_int_mismatch(op_t op, int arg, const tnode_t *ln, const tnode_t *rn) 3063 { 3064 3065 if (!eflag) 3066 return; 3067 3068 switch (op) { 3069 case INIT: 3070 /* 3071 * Initialization with 0 is allowed. Otherwise, all implicit 3072 * initializations would need to be warned upon as well. 3073 */ 3074 if (!rn->tn_type->t_is_enum && rn->tn_op == CON && 3075 is_integer(rn->tn_type->t_tspec) && 3076 rn->tn_val.u.integer == 0) { 3077 return; 3078 } 3079 /* initialization of '%s' with '%s' */ 3080 warning(277, type_name(ln->tn_type), type_name(rn->tn_type)); 3081 break; 3082 case FARG: 3083 /* combination of '%s' and '%s', arg #%d */ 3084 warning(278, 3085 type_name(ln->tn_type), type_name(rn->tn_type), arg); 3086 break; 3087 case RETURN: 3088 /* combination of '%s' and '%s' in return */ 3089 warning(279, type_name(ln->tn_type), type_name(rn->tn_type)); 3090 break; 3091 default: 3092 /* combination of '%s' and '%s', op '%s' */ 3093 warning(242, type_name(ln->tn_type), type_name(rn->tn_type), 3094 op_name(op)); 3095 break; 3096 } 3097 } 3098 3099 static void 3100 typeok_enum(op_t op, const mod_t *mp, int arg, 3101 const tnode_t *ln, const type_t *ltp, 3102 const tnode_t *rn, const type_t *rtp) 3103 { 3104 if (mp->m_bad_on_enum && 3105 (ltp->t_is_enum || (mp->m_binary && rtp->t_is_enum))) { 3106 check_bad_enum_operation(op, ln, rn); 3107 } else if (mp->m_valid_on_enum && 3108 (ltp->t_is_enum && rtp != NULL && rtp->t_is_enum)) { 3109 check_enum_type_mismatch(op, arg, ln, rn); 3110 } else if (mp->m_valid_on_enum && 3111 (ltp->t_is_enum || (rtp != NULL && rtp->t_is_enum))) { 3112 check_enum_int_mismatch(op, arg, ln, rn); 3113 } 3114 } 3115 3116 /* Perform most type checks. Return whether the types are ok. */ 3117 bool 3118 typeok(op_t op, int arg, const tnode_t *ln, const tnode_t *rn) 3119 { 3120 3121 const mod_t *mp = &modtab[op]; 3122 3123 type_t *ltp = ln->tn_type; 3124 tspec_t lt = ltp->t_tspec; 3125 3126 type_t *rtp = mp->m_binary ? rn->tn_type : NULL; 3127 tspec_t rt = mp->m_binary ? rtp->t_tspec : NO_TSPEC; 3128 3129 if (Tflag && !typeok_scalar_strict_bool(op, mp, arg, ln, rn)) 3130 return false; 3131 if (!typeok_scalar(op, mp, ltp, lt, rtp, rt)) 3132 return false; 3133 3134 if (!typeok_op(op, arg, ln, ltp, lt, rn, rtp, rt)) 3135 return false; 3136 3137 typeok_enum(op, mp, arg, ln, ltp, rn, rtp); 3138 return true; 3139 } 3140 3141 /* In traditional C, keep unsigned and promote FLOAT to DOUBLE. */ 3142 static tspec_t 3143 promote_trad(tspec_t t) 3144 { 3145 3146 if (t == UCHAR || t == USHORT) 3147 return UINT; 3148 if (t == CHAR || t == SCHAR || t == SHORT) 3149 return INT; 3150 if (t == FLOAT) 3151 return DOUBLE; 3152 if (t == ENUM) 3153 return INT; 3154 return t; 3155 } 3156 3157 /* 3158 * C99 6.3.1.1p2 requires for types with lower rank than int that "If an int 3159 * can represent all the values of the original type, the value is converted 3160 * to an int; otherwise it is converted to an unsigned int", and that "All 3161 * other types are unchanged by the integer promotions". 3162 */ 3163 static tspec_t 3164 promote_c90(const tnode_t *tn, tspec_t t, bool farg) 3165 { 3166 if (tn->tn_type->t_bitfield) { 3167 unsigned int width = tn->tn_type->t_bit_field_width; 3168 unsigned int int_width = size_in_bits(INT); 3169 // XXX: What about _Bool bit-fields, since C99? 3170 if (width < int_width) 3171 return INT; 3172 if (width == int_width) 3173 return is_uinteger(t) ? UINT : INT; 3174 return t; 3175 } 3176 3177 if (t == CHAR || t == SCHAR) 3178 return INT; 3179 if (t == UCHAR) 3180 return size_in_bits(CHAR) < size_in_bits(INT) ? INT : UINT; 3181 if (t == SHORT) 3182 return INT; 3183 if (t == USHORT) 3184 return size_in_bits(SHORT) < size_in_bits(INT) ? INT : UINT; 3185 if (t == ENUM) 3186 return INT; 3187 if (farg && t == FLOAT) 3188 return DOUBLE; 3189 return t; 3190 } 3191 3192 /* 3193 * Performs the "integer promotions" (C99 6.3.1.1p2), which convert small 3194 * integer types to either int or unsigned int. 3195 * 3196 * If allow_c90 is unset or the operand is a function argument with no type 3197 * information (no prototype or variable # of args), converts float to double. 3198 */ 3199 tnode_t * 3200 promote(op_t op, bool farg, tnode_t *tn) 3201 { 3202 3203 tspec_t ot = tn->tn_type->t_tspec; 3204 if (!is_arithmetic(ot)) 3205 return tn; 3206 3207 tspec_t nt = allow_c90 ? promote_c90(tn, ot, farg) : promote_trad(ot); 3208 if (nt == ot) 3209 return tn; 3210 3211 type_t *ntp = expr_dup_type(tn->tn_type); 3212 ntp->t_tspec = nt; 3213 /* 3214 * Keep t_is_enum even though t_tspec gets converted from ENUM to INT, 3215 * so we are later able to check compatibility of enum types. 3216 */ 3217 return convert(op, 0, ntp, tn); 3218 } 3219 3220 static void 3221 convert_integer_from_floating(op_t op, const type_t *tp, const tnode_t *tn) 3222 { 3223 3224 if (op == CVT) 3225 /* cast from floating point '%s' to integer '%s' */ 3226 query_message(2, type_name(tn->tn_type), type_name(tp)); 3227 else 3228 /* implicit conversion from floating point '%s' to ... */ 3229 query_message(1, type_name(tn->tn_type), type_name(tp)); 3230 } 3231 3232 static bool 3233 should_warn_about_prototype_conversion(tspec_t nt, 3234 tspec_t ot, const tnode_t *ptn) 3235 { 3236 3237 if (nt == ot) 3238 return false; 3239 3240 if (nt == ENUM && ot == INT) 3241 return false; 3242 3243 if (is_floating(nt) != is_floating(ot) || 3244 portable_rank_cmp(nt, ot) != 0) { 3245 /* representation and/or width change */ 3246 if (!is_integer(ot)) 3247 return true; 3248 /* 3249 * XXX: Investigate whether this rule makes sense; see 3250 * tests/usr.bin/xlint/lint1/platform_long.c. 3251 */ 3252 return portable_rank_cmp(ot, INT) > 0; 3253 } 3254 3255 if (!hflag) 3256 return false; 3257 3258 /* 3259 * If the types differ only in sign and the argument has the same 3260 * representation in both types, print no warning. 3261 */ 3262 if (ptn->tn_op == CON && is_integer(nt) && 3263 signed_type(nt) == signed_type(ot) && 3264 !msb(ptn->tn_val.u.integer, ot)) 3265 return false; 3266 3267 return true; 3268 } 3269 3270 /* 3271 * Warn if a prototype causes a type conversion that is different from what 3272 * would happen to the same argument in the absence of a prototype. This 3273 * check is intended for code that needs to stay compatible with pre-C90 C. 3274 * 3275 * Errors/warnings about illegal type combinations are already printed 3276 * in check_assign_types_compatible(). 3277 */ 3278 static void 3279 check_prototype_conversion(int arg, tspec_t nt, tspec_t ot, type_t *tp, 3280 tnode_t *tn) 3281 { 3282 3283 if (!is_arithmetic(nt) || !is_arithmetic(ot)) 3284 return; 3285 3286 /* 3287 * If the type of the formal parameter is char/short, a warning would 3288 * be useless, because functions declared the old style can't expect 3289 * char/short arguments. 3290 */ 3291 if (nt == CHAR || nt == SCHAR || nt == UCHAR || 3292 nt == SHORT || nt == USHORT) 3293 return; 3294 3295 tnode_t *ptn = promote(NOOP, true, tn); 3296 ot = ptn->tn_type->t_tspec; 3297 3298 if (should_warn_about_prototype_conversion(nt, ot, ptn)) { 3299 /* argument %d is converted from '%s' to '%s' ... */ 3300 warning(259, arg, type_name(tn->tn_type), type_name(tp)); 3301 } 3302 } 3303 3304 /* 3305 * When converting a large integer type to a small integer type, in some 3306 * cases the value of the actual expression is further restricted than the 3307 * type bounds, such as in (expr & 0xFF) or (expr % 100) or (expr >> 24). 3308 */ 3309 static bool 3310 can_represent(const type_t *tp, const tnode_t *tn) 3311 { 3312 3313 debug_step("%s: type '%s'", __func__, type_name(tp)); 3314 debug_node(tn); 3315 3316 uint64_t nmask = value_bits(width_in_bits(tp)); 3317 if (!is_uinteger(tp->t_tspec)) 3318 nmask >>= 1; 3319 3320 integer_constraints c = ic_expr(tn); 3321 if ((~c.bclr & ~nmask) == 0) 3322 return true; 3323 3324 integer_constraints tpc = ic_any(tp); 3325 if (is_uinteger(tp->t_tspec) 3326 ? tpc.umin <= c.umin && tpc.umax >= c.umax 3327 : tpc.smin <= c.smin && tpc.smax >= c.smax) 3328 return true; 3329 3330 return false; 3331 } 3332 3333 static bool 3334 should_warn_about_integer_conversion(const type_t *ntp, tspec_t nt, 3335 const tnode_t *otn, tspec_t ot) 3336 { 3337 3338 // XXX: The portable_rank_cmp aims at portable mode, independent of the 3339 // current platform, while can_represent acts on the actual type sizes 3340 // from the current platform. This mix is inconsistent, but anything 3341 // else would make the exact conditions too complicated to grasp. 3342 if (aflag > 0 && portable_rank_cmp(nt, ot) < 0) { 3343 if (ot == LONG || ot == ULONG 3344 || ot == LLONG || ot == ULLONG 3345 #ifdef INT128_SIZE 3346 || ot == INT128 || ot == UINT128 3347 #endif 3348 || aflag > 1) 3349 return !can_represent(ntp, otn); 3350 } 3351 return false; 3352 } 3353 3354 static void 3355 convert_integer_from_integer(op_t op, int arg, tspec_t nt, tspec_t ot, 3356 type_t *tp, tnode_t *tn) 3357 { 3358 3359 if (tn->tn_op == CON) 3360 return; 3361 3362 if (op == CVT) 3363 return; 3364 3365 if (Pflag && pflag && aflag > 0 && 3366 portable_rank_cmp(nt, ot) > 0 && 3367 is_uinteger(nt) != is_uinteger(ot)) { 3368 if (op == FARG) { 3369 /* conversion to '%s' may sign-extend ... */ 3370 warning(297, type_name(tp), arg); 3371 } else { 3372 /* conversion to '%s' may sign-extend ... */ 3373 warning(131, type_name(tp)); 3374 } 3375 } 3376 3377 if (Pflag && portable_rank_cmp(nt, ot) > 0 && 3378 (tn->tn_op == PLUS || tn->tn_op == MINUS || tn->tn_op == MULT || 3379 tn->tn_op == SHL)) { 3380 /* suggest cast from '%s' to '%s' on op '%s' to ... */ 3381 warning(324, type_name(gettyp(ot)), type_name(tp), 3382 op_name(tn->tn_op)); 3383 } 3384 3385 if (should_warn_about_integer_conversion(tp, nt, tn, ot)) { 3386 if (op == FARG) { 3387 /* conversion from '%s' to '%s' may lose ... */ 3388 warning(298, 3389 type_name(tn->tn_type), type_name(tp), arg); 3390 } else { 3391 /* conversion from '%s' to '%s' may lose accuracy */ 3392 warning(132, 3393 type_name(tn->tn_type), type_name(tp)); 3394 } 3395 } 3396 3397 if (any_query_enabled && is_uinteger(nt) != is_uinteger(ot)) 3398 /* implicit conversion changes sign from '%s' to '%s' */ 3399 query_message(3, type_name(tn->tn_type), type_name(tp)); 3400 } 3401 3402 static void 3403 convert_integer_from_pointer(op_t op, tspec_t nt, type_t *tp, tnode_t *tn) 3404 { 3405 3406 if (tn->tn_op == CON) 3407 return; 3408 if (op != CVT) 3409 return; /* We already got an error. */ 3410 if (portable_rank_cmp(nt, PTR) >= 0) 3411 return; 3412 3413 if (pflag && size_in_bits(nt) >= size_in_bits(PTR)) { 3414 /* conversion of pointer to '%s' may lose bits */ 3415 warning(134, type_name(tp)); 3416 } else { 3417 /* conversion of pointer to '%s' loses bits */ 3418 warning(133, type_name(tp)); 3419 } 3420 } 3421 3422 static bool 3423 struct_starts_with(const type_t *struct_tp, const type_t *member_tp) 3424 { 3425 3426 return struct_tp->t_sou->sou_first_member != NULL && 3427 types_compatible(struct_tp->t_sou->sou_first_member->s_type, 3428 member_tp, true, false, NULL); 3429 } 3430 3431 static bool 3432 is_byte_array(const type_t *tp) 3433 { 3434 3435 return tp->t_tspec == ARRAY && 3436 (tp->t_subt->t_tspec == CHAR || tp->t_subt->t_tspec == UCHAR); 3437 } 3438 3439 static bool 3440 union_contains(const type_t *utp, const type_t *mtp) 3441 { 3442 for (const sym_t *mem = utp->t_sou->sou_first_member; 3443 mem != NULL; mem = mem->s_next) { 3444 if (types_compatible(mem->s_type, mtp, true, false, NULL)) 3445 return true; 3446 } 3447 return false; 3448 } 3449 3450 static bool 3451 should_warn_about_pointer_cast(const type_t *nstp, tspec_t nst, 3452 const type_t *ostp, tspec_t ost) 3453 { 3454 3455 while (nst == ARRAY) 3456 nstp = nstp->t_subt, nst = nstp->t_tspec; 3457 while (ost == ARRAY) 3458 ostp = ostp->t_subt, ost = ostp->t_tspec; 3459 3460 if (nst == STRUCT && ost == STRUCT && 3461 (struct_starts_with(nstp, ostp) || 3462 struct_starts_with(ostp, nstp))) 3463 return false; 3464 3465 if (is_incomplete(nstp) || is_incomplete(ostp)) 3466 return false; 3467 3468 if (nst == CHAR || nst == UCHAR) 3469 return false; /* for the sake of traditional C code */ 3470 if (ost == CHAR || ost == UCHAR) 3471 return false; /* for the sake of traditional C code */ 3472 3473 /* Allow cast between pointers to sockaddr variants. */ 3474 if (nst == STRUCT && ost == STRUCT) { 3475 const sym_t *nmem = nstp->t_sou->sou_first_member; 3476 const sym_t *omem = ostp->t_sou->sou_first_member; 3477 while (nmem != NULL && omem != NULL && 3478 types_compatible(nmem->s_type, omem->s_type, 3479 true, false, NULL)) 3480 nmem = nmem->s_next, omem = omem->s_next; 3481 if (nmem != NULL && is_byte_array(nmem->s_type)) 3482 return false; 3483 if (omem != NULL && is_byte_array(omem->s_type)) 3484 return false; 3485 if (nmem == NULL && omem == NULL) 3486 return false; 3487 } 3488 3489 if (nst == UNION || ost == UNION) { 3490 const type_t *union_tp = nst == UNION ? nstp : ostp; 3491 const type_t *other_tp = nst == UNION ? ostp : nstp; 3492 if (union_contains(union_tp, other_tp)) 3493 return false; 3494 } 3495 3496 if (is_struct_or_union(nst) && is_struct_or_union(ost)) 3497 return nstp->t_sou != ostp->t_sou; 3498 3499 enum rank_kind rk1 = type_properties(nst)->tt_rank_kind; 3500 enum rank_kind rk2 = type_properties(ost)->tt_rank_kind; 3501 if (rk1 != rk2 || rk1 == RK_NONE) 3502 return true; 3503 3504 return portable_rank_cmp(nst, ost) != 0; 3505 } 3506 3507 static void 3508 convert_pointer_from_pointer(type_t *ntp, tnode_t *tn) 3509 { 3510 const type_t *nstp = ntp->t_subt; 3511 const type_t *otp = tn->tn_type; 3512 const type_t *ostp = otp->t_subt; 3513 tspec_t nst = nstp->t_tspec; 3514 tspec_t ost = ostp->t_tspec; 3515 3516 if (nst == VOID || ost == VOID) { 3517 /* TODO: C99 behaves like C90 here. */ 3518 if ((!allow_trad && !allow_c99) && (nst == FUNC || ost == FUNC)) { 3519 const char *nts, *ots; 3520 /* null pointers are already handled in convert() */ 3521 *(nst == FUNC ? &nts : &ots) = "function pointer"; 3522 *(nst == VOID ? &nts : &ots) = "'void *'"; 3523 /* conversion of %s to %s requires a cast */ 3524 warning(303, ots, nts); 3525 } 3526 return; 3527 } 3528 if (nst == FUNC && ost == FUNC) 3529 return; 3530 if (nst == FUNC || ost == FUNC) { 3531 /* converting '%s' to '%s' is questionable */ 3532 warning(229, type_name(otp), type_name(ntp)); 3533 return; 3534 } 3535 3536 if (hflag && alignment_in_bits(nstp) > alignment_in_bits(ostp) && 3537 ost != CHAR && ost != UCHAR && 3538 !is_incomplete(ostp) && 3539 !(nst == UNION && union_contains(nstp, ostp))) { 3540 /* converting '%s' to '%s' increases alignment ... */ 3541 warning(135, type_name(otp), type_name(ntp), 3542 alignment_in_bits(ostp) / CHAR_SIZE, 3543 alignment_in_bits(nstp) / CHAR_SIZE); 3544 } 3545 3546 if (cflag && should_warn_about_pointer_cast(nstp, nst, ostp, ost)) { 3547 /* pointer cast from '%s' to '%s' may be troublesome */ 3548 warning(247, type_name(otp), type_name(ntp)); 3549 } 3550 } 3551 3552 /* 3553 * Insert a conversion operator, which converts the type of the node 3554 * to another given type. 3555 * 3556 * Possible values for 'op': 3557 * CVT a cast-expression 3558 * binary integer promotion for one of the operands, or a usual 3559 * arithmetic conversion 3560 * binary plain or compound assignments to bit-fields 3561 * FARG 'arg' is the number of the parameter (used for warnings) 3562 * NOOP several other implicit conversions 3563 * ... 3564 */ 3565 tnode_t * 3566 convert(op_t op, int arg, type_t *tp, tnode_t *tn) 3567 { 3568 tspec_t nt = tp->t_tspec; 3569 tspec_t ot = tn->tn_type->t_tspec; 3570 3571 if (allow_trad && allow_c90 && op == FARG) 3572 check_prototype_conversion(arg, nt, ot, tp, tn); 3573 3574 if (nt == BOOL) { 3575 /* No further checks. */ 3576 3577 } else if (is_integer(nt)) { 3578 if (ot == BOOL) { 3579 /* No further checks. */ 3580 } else if (is_integer(ot)) 3581 convert_integer_from_integer(op, arg, nt, ot, tp, tn); 3582 else if (is_floating(ot)) 3583 convert_integer_from_floating(op, tp, tn); 3584 else if (ot == PTR) 3585 convert_integer_from_pointer(op, nt, tp, tn); 3586 3587 } else if (is_floating(nt)) { 3588 /* No further checks. */ 3589 3590 } else if (nt == PTR) { 3591 if (is_null_pointer(tn)) { 3592 /* a null pointer may be assigned to any pointer. */ 3593 } else if (ot == PTR && op == CVT) 3594 convert_pointer_from_pointer(tp, tn); 3595 } 3596 3597 tnode_t *ntn = expr_alloc_tnode(); 3598 ntn->tn_op = CVT; 3599 ntn->tn_type = tp; 3600 ntn->tn_cast = op == CVT; 3601 ntn->tn_sys |= tn->tn_sys; 3602 ntn->tn_right = NULL; 3603 if (tn->tn_op != CON || nt == VOID) { 3604 ntn->tn_left = tn; 3605 } else { 3606 ntn->tn_op = CON; 3607 convert_constant(op, arg, ntn->tn_type, &ntn->tn_val, 3608 &tn->tn_val); 3609 } 3610 3611 return ntn; 3612 } 3613 3614 static void 3615 convert_constant_floating(op_t op, int arg, tspec_t ot, const type_t *tp, 3616 tspec_t nt, val_t *v, val_t *nv) 3617 { 3618 long double max = 0.0, min = 0.0; 3619 3620 switch (nt) { 3621 case CHAR: 3622 max = TARG_CHAR_MAX; min = TARG_CHAR_MIN; break; 3623 case UCHAR: 3624 max = TARG_UCHAR_MAX; min = 0; break; 3625 case SCHAR: 3626 max = TARG_SCHAR_MAX; min = TARG_SCHAR_MIN; break; 3627 case SHORT: 3628 max = TARG_SHRT_MAX; min = TARG_SHRT_MIN; break; 3629 case USHORT: 3630 max = TARG_USHRT_MAX; min = 0; break; 3631 case ENUM: 3632 case INT: 3633 max = TARG_INT_MAX; min = TARG_INT_MIN; break; 3634 case UINT: 3635 max = TARG_UINT_MAX; min = 0; break; 3636 case LONG: 3637 max = TARG_LONG_MAX; min = TARG_LONG_MIN; break; 3638 case ULONG: 3639 max = TARG_ULONG_MAX; min = 0; break; 3640 case LLONG: 3641 max = LLONG_MAX; min = LLONG_MIN; break; 3642 case ULLONG: 3643 max = ULLONG_MAX; min = 0; break; 3644 case FLOAT: 3645 case FCOMPLEX: 3646 max = FLT_MAX; min = -FLT_MAX; break; 3647 case DOUBLE: 3648 case DCOMPLEX: 3649 max = DBL_MAX; min = -DBL_MAX; break; 3650 case PTR: 3651 /* Already got an error because of float --> ptr */ 3652 case LDOUBLE: 3653 case LCOMPLEX: 3654 /* LINTED 248 */ 3655 max = LDBL_MAX; min = -max; break; 3656 default: 3657 lint_assert(/*CONSTCOND*/false); 3658 } 3659 if (v->u.floating > max || v->u.floating < min) { 3660 lint_assert(nt != LDOUBLE); 3661 if (op == FARG) { 3662 /* conversion of '%s' to '%s' is out of range, ... */ 3663 warning(295, 3664 type_name(gettyp(ot)), type_name(tp), arg); 3665 } else { 3666 /* conversion of '%s' to '%s' is out of range */ 3667 warning(119, type_name(gettyp(ot)), type_name(tp)); 3668 } 3669 v->u.floating = v->u.floating > 0 ? max : min; 3670 } 3671 3672 if (nt == FLOAT || nt == FCOMPLEX) 3673 nv->u.floating = (float)v->u.floating; 3674 else if (nt == DOUBLE || nt == DCOMPLEX) 3675 nv->u.floating = (double)v->u.floating; 3676 else if (nt == LDOUBLE || nt == LCOMPLEX) 3677 nv->u.floating = v->u.floating; 3678 else 3679 nv->u.integer = (int64_t)v->u.floating; 3680 } 3681 3682 static bool 3683 convert_constant_to_floating(tspec_t nt, val_t *nv, 3684 tspec_t ot, const val_t *v) 3685 { 3686 if (nt == FLOAT) { 3687 nv->u.floating = (ot == PTR || is_uinteger(ot)) ? 3688 (float)(uint64_t)v->u.integer : (float)v->u.integer; 3689 } else if (nt == DOUBLE) { 3690 nv->u.floating = (ot == PTR || is_uinteger(ot)) ? 3691 (double)(uint64_t)v->u.integer : (double)v->u.integer; 3692 } else if (nt == LDOUBLE) { 3693 nv->u.floating = (ot == PTR || is_uinteger(ot)) 3694 ? (long double)(uint64_t)v->u.integer 3695 : (long double)v->u.integer; 3696 } else 3697 return false; 3698 return true; 3699 } 3700 3701 /* 3702 * Print a warning if bits which were set are lost due to the conversion. 3703 * This can happen with operator ORASS only. 3704 */ 3705 static void 3706 convert_constant_check_range_bitor(size_t nsz, size_t osz, const val_t *v, 3707 uint64_t xmask, op_t op) 3708 { 3709 if (nsz < osz && (v->u.integer & xmask) != 0) { 3710 /* constant truncated by conversion, op '%s' */ 3711 warning(306, op_name(op)); 3712 } 3713 } 3714 3715 static void 3716 convert_constant_check_range_bitand(size_t nsz, size_t osz, 3717 uint64_t xmask, const val_t *nv, 3718 tspec_t ot, const val_t *v, 3719 const type_t *tp, op_t op) 3720 { 3721 if (nsz > osz && 3722 (nv->u.integer & bit((unsigned int)(osz - 1))) != 0 && 3723 (nv->u.integer & xmask) != xmask) { 3724 /* extra bits set to 0 in conversion of '%s' to '%s', ... */ 3725 warning(309, type_name(gettyp(ot)), 3726 type_name(tp), op_name(op)); 3727 } else if (nsz < osz && 3728 (v->u.integer & xmask) != xmask && 3729 (v->u.integer & xmask) != 0) { 3730 /* constant truncated by conversion, op '%s' */ 3731 warning(306, op_name(op)); 3732 } 3733 } 3734 3735 static void 3736 convert_constant_check_range_signed(op_t op, int arg) 3737 { 3738 if (op == ASSIGN) { 3739 /* assignment of negative constant to unsigned type */ 3740 warning(164); 3741 } else if (op == INIT) { 3742 /* initialization of unsigned with negative constant */ 3743 warning(221); 3744 } else if (op == FARG) { 3745 /* conversion of negative constant to unsigned type, ... */ 3746 warning(296, arg); 3747 } else if (modtab[op].m_comparison) { 3748 /* handled by check_integer_comparison() */ 3749 } else { 3750 /* conversion of negative constant to unsigned type */ 3751 warning(222); 3752 } 3753 } 3754 3755 /* 3756 * Loss of significant bit(s). All truncated bits of unsigned types or all 3757 * truncated bits plus the msb of the target for signed types are considered 3758 * to be significant bits. Loss of significant bits means that at least one 3759 * of the bits was set in an unsigned type or that at least one but not all 3760 * of the bits was set in a signed type. Loss of significant bits means that 3761 * it is not possible, also not with necessary casts, to convert back to the 3762 * original type. An example for a necessary cast is: 3763 * char c; int i; c = 128; 3764 * i = c; ** yields -128 ** 3765 * i = (unsigned char)c; ** yields 128 ** 3766 */ 3767 static void 3768 warn_constant_check_range_truncated(op_t op, int arg, const type_t *tp, 3769 tspec_t ot) 3770 { 3771 if (op == ASSIGN && tp->t_bitfield) 3772 /* precision lost in bit-field assignment */ 3773 warning(166); 3774 else if (op == ASSIGN) 3775 /* constant truncated by assignment */ 3776 warning(165); 3777 else if (op == INIT && tp->t_bitfield) 3778 /* bit-field initializer does not fit */ 3779 warning(180); 3780 else if (op == INIT) 3781 /* initializer does not fit */ 3782 warning(178); 3783 else if (op == CASE) 3784 /* case label affected by conversion */ 3785 warning(196); 3786 else if (op == FARG) 3787 /* conversion of '%s' to '%s' is out of range, arg #%d */ 3788 warning(295, type_name(gettyp(ot)), type_name(tp), arg); 3789 else 3790 /* conversion of '%s' to '%s' is out of range */ 3791 warning(119, type_name(gettyp(ot)), type_name(tp)); 3792 } 3793 3794 static void 3795 warn_constant_check_range_loss(op_t op, int arg, const type_t *tp, 3796 tspec_t ot) 3797 { 3798 if (op == ASSIGN && tp->t_bitfield) 3799 /* precision lost in bit-field assignment */ 3800 warning(166); 3801 else if (op == INIT && tp->t_bitfield) 3802 /* bit-field initializer out of range */ 3803 warning(11); 3804 else if (op == CASE) 3805 /* case label affected by conversion */ 3806 warning(196); 3807 else if (op == FARG) 3808 /* conversion of '%s' to '%s' is out of range, arg #%d */ 3809 warning(295, type_name(gettyp(ot)), type_name(tp), arg); 3810 else 3811 /* conversion of '%s' to '%s' is out of range */ 3812 warning(119, type_name(gettyp(ot)), type_name(tp)); 3813 } 3814 3815 static void 3816 convert_constant_check_range(tspec_t ot, const type_t *tp, tspec_t nt, 3817 op_t op, int arg, const val_t *v, val_t *nv) 3818 { 3819 unsigned int obitsz, nbitsz; 3820 uint64_t xmask, xmsk1; 3821 3822 obitsz = size_in_bits(ot); 3823 nbitsz = tp->t_bitfield ? tp->t_bit_field_width : size_in_bits(nt); 3824 xmask = value_bits(nbitsz) ^ value_bits(obitsz); 3825 xmsk1 = value_bits(nbitsz) ^ value_bits(obitsz - 1); 3826 if (op == ORASS || op == BITOR || op == BITXOR) { 3827 convert_constant_check_range_bitor( 3828 nbitsz, obitsz, v, xmask, op); 3829 } else if (op == ANDASS || op == BITAND) { 3830 convert_constant_check_range_bitand( 3831 nbitsz, obitsz, xmask, nv, ot, v, tp, op); 3832 } else if ((nt != PTR && is_uinteger(nt)) && 3833 (ot != PTR && !is_uinteger(ot)) && 3834 v->u.integer < 0) 3835 convert_constant_check_range_signed(op, arg); 3836 else if (nv->u.integer != v->u.integer && nbitsz <= obitsz && 3837 (v->u.integer & xmask) != 0 && 3838 (is_uinteger(ot) || (v->u.integer & xmsk1) != xmsk1)) 3839 warn_constant_check_range_truncated(op, arg, tp, ot); 3840 else if (nv->u.integer != v->u.integer) 3841 warn_constant_check_range_loss(op, arg, tp, ot); 3842 } 3843 3844 /*- 3845 * Converts a typed constant to a constant of another type. 3846 * 3847 * op operator which requires conversion 3848 * arg if op is FARG, # of parameter 3849 * tp type to which to convert the constant 3850 * nv new constant 3851 * v old constant 3852 */ 3853 void 3854 convert_constant(op_t op, int arg, const type_t *tp, val_t *nv, val_t *v) 3855 { 3856 /* 3857 * TODO: make 'v' const; the name of this function does not suggest 3858 * that it modifies 'v'. 3859 */ 3860 tspec_t ot = v->v_tspec; 3861 tspec_t nt = nv->v_tspec = tp->t_tspec; 3862 bool range_check = false; 3863 3864 if (nt == BOOL) { /* C99 6.3.1.2 */ 3865 nv->v_unsigned_since_c90 = false; 3866 nv->u.integer = is_nonzero_val(v) ? 1 : 0; 3867 return; 3868 } 3869 3870 if (ot == FLOAT || ot == DOUBLE || ot == LDOUBLE) 3871 convert_constant_floating(op, arg, ot, tp, nt, v, nv); 3872 else if (!convert_constant_to_floating(nt, nv, ot, v)) { 3873 range_check = true; /* Check for lost precision. */ 3874 nv->u.integer = v->u.integer; 3875 } 3876 3877 if (allow_trad && allow_c90 && v->v_unsigned_since_c90 && 3878 (is_floating(nt) || ( 3879 (is_integer(nt) && !is_uinteger(nt) && 3880 portable_rank_cmp(nt, ot) > 0)))) { 3881 /* C90 treats constant as unsigned */ 3882 warning(157); 3883 v->v_unsigned_since_c90 = false; 3884 } 3885 3886 if (is_integer(nt)) { 3887 nv->u.integer = convert_integer(nv->u.integer, nt, 3888 tp->t_bitfield ? tp->t_bit_field_width : size_in_bits(nt)); 3889 } 3890 3891 if (range_check && op != CVT) 3892 convert_constant_check_range(ot, tp, nt, op, arg, v, nv); 3893 } 3894 3895 tnode_t * 3896 build_sizeof(const type_t *tp) 3897 { 3898 unsigned int size_in_bytes = type_size_in_bits(tp) / CHAR_SIZE; 3899 tnode_t *tn = build_integer_constant(SIZEOF_TSPEC, size_in_bytes); 3900 tn->tn_system_dependent = true; 3901 debug_step("build_sizeof '%s' = %u", type_name(tp), size_in_bytes); 3902 return tn; 3903 } 3904 3905 tnode_t * 3906 build_offsetof(const type_t *tp, const sym_t *sym) 3907 { 3908 unsigned int offset_in_bits = 0; 3909 3910 if (!is_struct_or_union(tp->t_tspec)) { 3911 /* unacceptable operand of '%s' */ 3912 error(111, "offsetof"); 3913 goto proceed; 3914 } 3915 sym_t *mem = find_member(tp->t_sou, sym->s_name); 3916 if (mem == NULL) { 3917 /* type '%s' does not have member '%s' */ 3918 error(101, sym->s_name, type_name(tp)); 3919 goto proceed; 3920 } 3921 offset_in_bits = mem->u.s_member.sm_offset_in_bits; 3922 3923 proceed:; 3924 unsigned int offset_in_bytes = offset_in_bits / CHAR_SIZE; 3925 tnode_t *tn = build_integer_constant(SIZEOF_TSPEC, offset_in_bytes); 3926 tn->tn_system_dependent = true; 3927 return tn; 3928 } 3929 3930 unsigned int 3931 type_size_in_bits(const type_t *tp) 3932 { 3933 3934 unsigned int elem = 1; 3935 bool flex = false; 3936 lint_assert(tp != NULL); 3937 while (tp->t_tspec == ARRAY) { 3938 flex = true; /* allow c99 flex arrays [] [0] */ 3939 elem *= tp->t_dim; 3940 tp = tp->t_subt; 3941 } 3942 if (elem == 0 && !flex) { 3943 /* cannot take size/alignment of incomplete type */ 3944 error(143); 3945 elem = 1; 3946 } 3947 3948 unsigned int elsz; 3949 switch (tp->t_tspec) { 3950 case VOID: 3951 /* cannot take size/alignment of void */ 3952 error(146); 3953 elsz = 1; 3954 break; 3955 case FUNC: 3956 /* cannot take size/alignment of function type '%s' */ 3957 error(144, type_name(tp)); 3958 elsz = 1; 3959 break; 3960 case STRUCT: 3961 case UNION: 3962 if (is_incomplete(tp)) { 3963 /* cannot take size/alignment of incomplete type */ 3964 error(143); 3965 elsz = 1; 3966 } else { 3967 elsz = tp->t_sou->sou_size_in_bits; 3968 } 3969 break; 3970 case ENUM: 3971 if (is_incomplete(tp)) { 3972 /* cannot take size/alignment of incomplete type */ 3973 warning(143); 3974 } 3975 /* FALLTHROUGH */ 3976 default: 3977 if (tp->t_bitfield) { 3978 /* cannot take size/alignment of bit-field */ 3979 error(145); 3980 } 3981 elsz = size_in_bits(tp->t_tspec); 3982 lint_assert(elsz > 0); 3983 break; 3984 } 3985 3986 return elem * elsz; 3987 } 3988 3989 /* C11 6.5.3.4, GCC */ 3990 tnode_t * 3991 build_alignof(const type_t *tp) 3992 { 3993 if (tp->t_tspec == FUNC) { 3994 /* cannot take size/alignment of function type '%s' */ 3995 error(144, type_name(tp)); 3996 return NULL; 3997 } 3998 if (tp->t_tspec == VOID) { 3999 /* cannot take size/alignment of void */ 4000 error(146); 4001 return NULL; 4002 } 4003 if (is_incomplete(tp)) { 4004 /* cannot take size/alignment of incomplete type */ 4005 error(143); 4006 return NULL; 4007 } 4008 if (tp->t_bitfield) { 4009 /* cannot take size/alignment of bit-field */ 4010 error(145); 4011 return NULL; 4012 } 4013 return build_integer_constant(SIZEOF_TSPEC, 4014 (int64_t)alignment_in_bits(tp) / CHAR_SIZE); 4015 } 4016 4017 static tnode_t * 4018 cast_to_union(tnode_t *otn, type_t *ntp) 4019 { 4020 4021 if (!allow_gcc) { 4022 /* union cast is a GCC extension */ 4023 error(328); 4024 return NULL; 4025 } 4026 4027 for (const sym_t *m = ntp->t_sou->sou_first_member; 4028 m != NULL; m = m->s_next) { 4029 if (types_compatible(m->s_type, otn->tn_type, 4030 false, false, NULL)) { 4031 tnode_t *ntn = expr_alloc_tnode(); 4032 ntn->tn_op = CVT; 4033 ntn->tn_type = ntp; 4034 ntn->tn_cast = true; 4035 ntn->tn_left = otn; 4036 ntn->tn_right = NULL; 4037 return ntn; 4038 } 4039 } 4040 4041 /* type '%s' is not a member of '%s' */ 4042 error(329, type_name(otn->tn_type), type_name(ntp)); 4043 return NULL; 4044 } 4045 4046 tnode_t * 4047 cast(tnode_t *tn, type_t *tp) 4048 { 4049 4050 if (tn == NULL) 4051 return NULL; 4052 4053 tn = cconv(tn); 4054 4055 lint_assert(tp != NULL); 4056 tspec_t nt = tp->t_tspec; 4057 tspec_t ot = tn->tn_type->t_tspec; 4058 4059 if (nt == VOID) { 4060 /* 4061 * C90 6.3.4, C99 6.5.4p2 and C11 6.5.4p2 allow any type to be 4062 * cast to void. The only other allowed casts are from a 4063 * scalar type to a scalar type. 4064 */ 4065 } else if (nt == UNION) 4066 return cast_to_union(tn, tp); 4067 else if (nt == STRUCT || nt == ARRAY || nt == FUNC) { 4068 /* Casting to a struct is an undocumented GCC extension. */ 4069 if (!(allow_gcc && nt == STRUCT)) 4070 goto invalid_cast; 4071 } else if (is_struct_or_union(ot)) 4072 goto invalid_cast; 4073 else if (ot == VOID) { 4074 /* improper cast of void expression */ 4075 error(148); 4076 return NULL; 4077 } else if (is_integer(nt) && is_scalar(ot)) { 4078 /* ok */ 4079 } else if (is_floating(nt) && is_arithmetic(ot)) { 4080 /* ok */ 4081 } else if (nt == PTR && is_integer(ot)) { 4082 /* ok */ 4083 } else if (nt == PTR && ot == PTR) { 4084 if (!tp->t_subt->t_const && tn->tn_type->t_subt->t_const) { 4085 if (hflag) 4086 /* cast discards 'const' from type '%s' */ 4087 warning(275, type_name(tn->tn_type)); 4088 } 4089 } else 4090 goto invalid_cast; 4091 4092 if (any_query_enabled && types_compatible(tp, tn->tn_type, 4093 false, false, NULL)) { 4094 /* no-op cast from '%s' to '%s' */ 4095 query_message(6, type_name(tn->tn_type), type_name(tp)); 4096 } 4097 4098 tn = convert(CVT, 0, tp, tn); 4099 tn->tn_cast = true; 4100 4101 return tn; 4102 4103 invalid_cast: 4104 /* invalid cast from '%s' to '%s' */ 4105 error(147, type_name(tn->tn_type), type_name(tp)); 4106 return NULL; 4107 } 4108 4109 /* 4110 * Create the node for a function argument. 4111 * All necessary conversions and type checks are done in 4112 * build_function_call because build_function_argument has no 4113 * information about the expected parameter types. 4114 */ 4115 tnode_t * 4116 build_function_argument(tnode_t *args, tnode_t *arg) 4117 { 4118 /* 4119 * If there was a serious error in the expression for the argument, 4120 * create a dummy argument so the positions of the remaining arguments 4121 * will not change. 4122 */ 4123 if (arg == NULL) 4124 arg = build_integer_constant(INT, 0); 4125 4126 return build_op(PUSH, arg->tn_sys, arg->tn_type, arg, args); 4127 } 4128 4129 /* 4130 * Compare the type of an argument with the corresponding type of a 4131 * prototype parameter. If it is a valid combination, but both types 4132 * are not the same, insert a conversion to convert the argument into 4133 * the type of the parameter. 4134 */ 4135 static tnode_t * 4136 check_prototype_argument( 4137 int n, /* pos of arg */ 4138 type_t *tp, /* expected type (from prototype) */ 4139 tnode_t *tn) /* argument */ 4140 { 4141 tnode_t *ln = xcalloc(1, sizeof(*ln)); 4142 ln->tn_type = expr_unqualified_type(tp); 4143 ln->tn_lvalue = true; 4144 if (typeok(FARG, n, ln, tn)) { 4145 bool dowarn; 4146 if (!types_compatible(tp, tn->tn_type, 4147 true, false, (dowarn = false, &dowarn)) || dowarn) 4148 tn = convert(FARG, n, tp, tn); 4149 } 4150 free(ln); 4151 return tn; 4152 } 4153 4154 /* 4155 * Check types of all function arguments and insert conversions, 4156 * if necessary. 4157 */ 4158 static tnode_t * 4159 check_function_arguments(type_t *ftp, tnode_t *args) 4160 { 4161 /* get # of parameters in the prototype */ 4162 int npar = 0; 4163 for (const sym_t *p = ftp->t_params; p != NULL; p = p->s_next) 4164 npar++; 4165 4166 /* get # of arguments in the function call */ 4167 int narg = 0; 4168 for (const tnode_t *arg = args; arg != NULL; arg = tn_ck_right(arg)) 4169 narg++; 4170 4171 const sym_t *param = ftp->t_params; 4172 if (ftp->t_proto && npar != narg && !(ftp->t_vararg && npar < narg)) { 4173 /* argument mismatch: %d %s passed, %d expected */ 4174 error(150, narg, narg != 1 ? "arguments" : "argument", npar); 4175 param = NULL; 4176 } 4177 4178 for (int n = 1; n <= narg; n++) { 4179 4180 // The rightmost argument starts the argument list. 4181 tnode_t *arg = args; 4182 for (int i = narg; i > n; i--, arg = arg->tn_right) 4183 continue; 4184 4185 /* some things which are always not allowed */ 4186 tspec_t at = arg->tn_left->tn_type->t_tspec; 4187 if (at == VOID) { 4188 /* void expressions may not be arguments, arg #%d */ 4189 error(151, n); 4190 return NULL; 4191 } 4192 if (is_struct_or_union(at) && 4193 is_incomplete(arg->tn_left->tn_type)) { 4194 /* argument cannot have unknown size, arg #%d */ 4195 error(152, n); 4196 return NULL; 4197 } 4198 if (is_integer(at) && 4199 arg->tn_left->tn_type->t_is_enum && 4200 is_incomplete(arg->tn_left->tn_type)) { 4201 /* argument cannot have unknown size, arg #%d */ 4202 warning(152, n); 4203 } 4204 4205 arg->tn_left = cconv(arg->tn_left); 4206 4207 if (param != NULL) { 4208 arg->tn_left = check_prototype_argument( 4209 n, param->s_type, arg->tn_left); 4210 } else 4211 arg->tn_left = promote(NOOP, true, arg->tn_left); 4212 arg->tn_type = arg->tn_left->tn_type; 4213 4214 if (param != NULL) 4215 param = param->s_next; 4216 } 4217 4218 return args; 4219 } 4220 4221 tnode_t * 4222 build_function_call(tnode_t *func, bool sys, tnode_t *args) 4223 { 4224 4225 if (func == NULL) 4226 return NULL; 4227 4228 op_t fcop = func->tn_op == NAME && func->tn_type->t_tspec == FUNC 4229 ? CALL : ICALL; 4230 4231 check_ctype_function_call(func, args); 4232 4233 func = cconv(func); 4234 4235 if (func->tn_type->t_tspec != PTR || 4236 func->tn_type->t_subt->t_tspec != FUNC) { 4237 /* cannot call '%s', must be a function */ 4238 error(149, type_name(func->tn_type)); 4239 return NULL; 4240 } 4241 4242 args = check_function_arguments(func->tn_type->t_subt, args); 4243 4244 return build_op(fcop, sys, func->tn_type->t_subt->t_subt, func, args); 4245 } 4246 4247 /* 4248 * Return the value of an integral constant expression. 4249 * If the expression is not constant or its type is not an integer 4250 * type, an error message is printed. 4251 */ 4252 val_t * 4253 integer_constant(tnode_t *tn, bool required) 4254 { 4255 4256 if (tn != NULL) 4257 tn = cconv(tn); 4258 if (tn != NULL) 4259 tn = promote(NOOP, false, tn); 4260 4261 val_t *v = xcalloc(1, sizeof(*v)); 4262 4263 if (tn == NULL) { 4264 lint_assert(seen_error); 4265 debug_step("constant node is null; returning 1 instead"); 4266 v->v_tspec = INT; 4267 v->u.integer = 1; 4268 return v; 4269 } 4270 4271 v->v_tspec = tn->tn_type->t_tspec; 4272 4273 if (tn->tn_op == CON) { 4274 lint_assert(tn->tn_type->t_tspec == tn->tn_val.v_tspec); 4275 if (is_integer(tn->tn_val.v_tspec)) { 4276 v->v_unsigned_since_c90 = 4277 tn->tn_val.v_unsigned_since_c90; 4278 v->u.integer = tn->tn_val.u.integer; 4279 return v; 4280 } 4281 v->u.integer = (int64_t)tn->tn_val.u.floating; 4282 } else { 4283 v->u.integer = 1; 4284 } 4285 4286 if (required) 4287 /* integral constant expression expected */ 4288 error(55); 4289 else 4290 /* variable array dimension is a C99/GCC extension */ 4291 c99ism(318); 4292 4293 if (!is_integer(v->v_tspec)) 4294 v->v_tspec = INT; 4295 4296 return v; 4297 } 4298 4299 static bool 4300 is_constcond_false(const tnode_t *tn, tspec_t t) 4301 { 4302 return (t == BOOL || t == INT) && 4303 tn->tn_op == CON && tn->tn_val.u.integer == 0; 4304 } 4305 4306 /* 4307 * Perform some tests on expressions which can't be done in build_binary() 4308 * and functions called by build_binary(). These tests must be done here 4309 * because we need some information about the context in which the operations 4310 * are performed. 4311 * After all tests are performed and dofreeblk is true, expr() frees the 4312 * memory which is used for the expression. 4313 */ 4314 void 4315 expr(tnode_t *tn, bool vctx, bool cond, bool dofreeblk, bool is_do_while) 4316 { 4317 4318 if (tn == NULL) { /* in case of errors */ 4319 expr_free_all(); 4320 return; 4321 } 4322 4323 /* expr() is also called in global initializations */ 4324 if (dcs->d_kind != DLK_EXTERN && !is_do_while) 4325 check_statement_reachable(); 4326 4327 check_expr_misc(tn, vctx, cond, !cond, false, false, false); 4328 if (tn->tn_op == ASSIGN && !tn->tn_parenthesized) { 4329 if (hflag && cond) 4330 /* assignment in conditional context */ 4331 warning(159); 4332 } else if (tn->tn_op == CON) { 4333 if (hflag && cond && !suppress_constcond && 4334 !tn->tn_system_dependent && 4335 !(is_do_while && 4336 is_constcond_false(tn, tn->tn_type->t_tspec))) 4337 /* constant in conditional context */ 4338 warning(161); 4339 } 4340 if (!modtab[tn->tn_op].m_has_side_effect) { 4341 /* 4342 * for left operands of COMMA this warning is already printed 4343 */ 4344 if (tn->tn_op != COMMA && !vctx && !cond) 4345 check_null_effect(tn); 4346 } 4347 debug_node(tn); 4348 4349 if (dofreeblk) 4350 expr_free_all(); 4351 } 4352 4353 /* 4354 * Checks the range of array indices, if possible. 4355 * amper is set if only the address of the element is used. This 4356 * means that the index is allowed to refer to the first element 4357 * after the array. 4358 */ 4359 static void 4360 check_array_index(tnode_t *tn, bool amper) 4361 { 4362 lint_assert(has_operands(tn)); 4363 const tnode_t *ln = tn->tn_left; 4364 const tnode_t *rn = tn->tn_right; 4365 4366 /* We can only check constant indices. */ 4367 if (rn->tn_op != CON) 4368 return; 4369 4370 /* Return if the left node does not stem from an array. */ 4371 if (ln->tn_op != ADDR) 4372 return; 4373 if (ln->tn_left->tn_op != STRING && ln->tn_left->tn_op != NAME) 4374 return; 4375 if (ln->tn_left->tn_type->t_tspec != ARRAY) 4376 return; 4377 4378 /* 4379 * For incomplete array types, we can print a warning only if the index 4380 * is negative. 4381 */ 4382 if (is_incomplete(ln->tn_left->tn_type) && rn->tn_val.u.integer >= 0) 4383 return; 4384 4385 int elsz = length_in_bits(ln->tn_type->t_subt, NULL); 4386 if (elsz == 0) 4387 return; 4388 elsz /= CHAR_SIZE; 4389 4390 /* Change the unit of the index from bytes to element size. */ 4391 int64_t con = is_uinteger(rn->tn_type->t_tspec) 4392 ? (int64_t)((uint64_t)rn->tn_val.u.integer / elsz) 4393 : rn->tn_val.u.integer / elsz; 4394 4395 int dim = ln->tn_left->tn_type->t_dim + (amper ? 1 : 0); 4396 4397 if (!is_uinteger(rn->tn_type->t_tspec) && con < 0) { 4398 /* array subscript cannot be negative: %ld */ 4399 warning(167, (long)con); 4400 } else if (dim > 0 && (uint64_t)con >= (uint64_t)dim) { 4401 /* array subscript cannot be > %d: %ld */ 4402 warning(168, dim - 1, (long)con); 4403 } 4404 } 4405 4406 static void 4407 check_expr_addr(const tnode_t *ln, bool szof, bool fcall) 4408 { 4409 /* XXX: Taking warn_about_unreachable into account here feels wrong. */ 4410 if (ln->tn_op == NAME && (reached || !warn_about_unreachable)) { 4411 if (!szof) 4412 mark_as_set(ln->tn_sym); 4413 mark_as_used(ln->tn_sym, fcall, szof); 4414 } 4415 if (ln->tn_op == INDIR && ln->tn_left->tn_op == PLUS) 4416 check_array_index(ln->tn_left, true); 4417 } 4418 4419 static void 4420 check_expr_load(const tnode_t *ln) 4421 { 4422 if (ln->tn_op == INDIR && ln->tn_left->tn_op == PLUS) 4423 check_array_index(ln->tn_left, false); 4424 } 4425 4426 /* 4427 * If there is an asm statement in one of the compound statements around, 4428 * there may be other side effects, so don't warn. 4429 */ 4430 static bool 4431 is_asm_around(void) 4432 { 4433 for (decl_level *dl = dcs; dl != NULL; dl = dl->d_enclosing) 4434 if (dl->d_asm) 4435 return true; 4436 return false; 4437 } 4438 4439 static void 4440 check_expr_side_effect(const tnode_t *ln, bool szof) 4441 { 4442 4443 /* XXX: Taking warn_about_unreachable into account here feels wrong. */ 4444 if (ln->tn_op == NAME && (reached || !warn_about_unreachable)) { 4445 scl_t sc = ln->tn_sym->s_scl; 4446 if (sc != EXTERN && sc != STATIC && 4447 !ln->tn_sym->s_set && !szof && !is_asm_around()) { 4448 /* '%s' may be used before set */ 4449 warning(158, ln->tn_sym->s_name); 4450 mark_as_set(ln->tn_sym); 4451 } 4452 mark_as_used(ln->tn_sym, false, false); 4453 } 4454 } 4455 4456 static void 4457 check_expr_assign(const tnode_t *ln, bool szof) 4458 { 4459 /* XXX: Taking warn_about_unreachable into account here feels wrong. */ 4460 if (ln->tn_op == NAME && !szof && (reached || !warn_about_unreachable)) { 4461 mark_as_set(ln->tn_sym); 4462 if (ln->tn_sym->s_scl == EXTERN) 4463 outusg(ln->tn_sym); 4464 } 4465 if (ln->tn_op == INDIR && ln->tn_left->tn_op == PLUS) 4466 /* check the range of array indices */ 4467 check_array_index(ln->tn_left, false); 4468 } 4469 4470 static void 4471 check_expr_call(const tnode_t *tn, const tnode_t *ln, 4472 bool szof, bool vctx, bool cond, bool retval_discarded) 4473 { 4474 lint_assert(ln->tn_op == ADDR); 4475 lint_assert(ln->tn_left->tn_op == NAME); 4476 if (!szof && !is_compiler_builtin(ln->tn_left->tn_sym->s_name)) 4477 outcall(tn, vctx || cond, retval_discarded); 4478 } 4479 4480 static void 4481 check_expr_op(const tnode_t *tn, op_t op, const tnode_t *ln, 4482 bool szof, bool fcall, bool vctx, bool cond, 4483 bool retval_discarded, bool eqwarn) 4484 { 4485 switch (op) { 4486 case ADDR: 4487 check_expr_addr(ln, szof, fcall); 4488 break; 4489 case LOAD: 4490 check_expr_load(ln); 4491 /* FALLTHROUGH */ 4492 case PUSH: 4493 case INCBEF: 4494 case DECBEF: 4495 case INCAFT: 4496 case DECAFT: 4497 case ADDASS: 4498 case SUBASS: 4499 case MULASS: 4500 case DIVASS: 4501 case MODASS: 4502 case ANDASS: 4503 case ORASS: 4504 case XORASS: 4505 case SHLASS: 4506 case SHRASS: 4507 case REAL: 4508 case IMAG: 4509 check_expr_side_effect(ln, szof); 4510 break; 4511 case ASSIGN: 4512 check_expr_assign(ln, szof); 4513 break; 4514 case CALL: 4515 check_expr_call(tn, ln, szof, vctx, cond, retval_discarded); 4516 break; 4517 case EQ: 4518 if (hflag && eqwarn) 4519 /* operator '==' found where '=' was expected */ 4520 warning(160); 4521 break; 4522 default: 4523 break; 4524 } 4525 } 4526 4527 /* 4528 * vctx ??? 4529 * cond whether the expression is a condition that 4530 * will be compared with 0 4531 * eqwarn whether the operator '==' might be a 4532 * misspelled '=' 4533 * fcall whether the expression is a function call 4534 * retval_discarded whether the return value of a function call 4535 * is discarded; such calls will be analyzed by 4536 * lint2 in messages 4, 8 and 9 4537 * szof whether the expression is part of a sizeof 4538 * expression, which means that its value is 4539 * discarded since only the type is relevant 4540 */ 4541 void 4542 check_expr_misc(const tnode_t *tn, bool vctx, bool cond, 4543 bool eqwarn, bool fcall, bool retval_discarded, bool szof) 4544 { 4545 4546 if (tn == NULL) 4547 return; 4548 op_t op = tn->tn_op; 4549 if (op == NAME || op == CON || op == STRING) 4550 return; 4551 4552 lint_assert(has_operands(tn)); 4553 tnode_t *ln = tn->tn_left; 4554 tnode_t *rn = tn->tn_right; 4555 check_expr_op(tn, op, ln, 4556 szof, fcall, vctx, cond, retval_discarded, eqwarn); 4557 4558 const mod_t *mp = &modtab[op]; 4559 bool cvctx = mp->m_value_context; 4560 bool ccond = mp->m_compares_with_zero; 4561 bool eq = mp->m_warn_if_operand_eq && 4562 !ln->tn_parenthesized && 4563 rn != NULL && !rn->tn_parenthesized; 4564 4565 /* 4566 * Values of operands of ':' are not used if the type of at least 4567 * one of the operands (for GCC compatibility) is 'void'. 4568 * 4569 * XXX test/value context of QUEST should probably be used as 4570 * context for both operands of COLON. 4571 */ 4572 if (op == COLON && tn->tn_type->t_tspec == VOID) 4573 cvctx = ccond = false; 4574 bool discard = op == CVT && tn->tn_type->t_tspec == VOID; 4575 check_expr_misc(ln, cvctx, ccond, eq, op == CALL, discard, szof); 4576 4577 switch (op) { 4578 case PUSH: 4579 if (rn != NULL) 4580 check_expr_misc(rn, false, false, eq, false, false, 4581 szof); 4582 break; 4583 case LOGAND: 4584 case LOGOR: 4585 check_expr_misc(rn, false, true, eq, false, false, szof); 4586 break; 4587 case COLON: 4588 check_expr_misc(rn, cvctx, ccond, eq, false, false, szof); 4589 break; 4590 case COMMA: 4591 check_expr_misc(rn, vctx, cond, false, false, false, szof); 4592 break; 4593 default: 4594 if (mp->m_binary) 4595 check_expr_misc(rn, true, false, eq, false, false, 4596 szof); 4597 break; 4598 } 4599 } 4600 4601 /* 4602 * Return whether the expression can be used for static initialization. 4603 * 4604 * Constant initialization expressions must be constant or an address 4605 * of a static object with an optional offset. In the first case, 4606 * the result is returned in *offsp. In the second case, the static 4607 * object is returned in *symp and the offset in *offsp. 4608 * 4609 * The expression can consist of PLUS, MINUS, ADDR, NAME, STRING and 4610 * CON. Type conversions are allowed if they do not change binary 4611 * representation (including width). 4612 * 4613 * C99 6.6 "Constant expressions" 4614 * C99 6.7.8p4 restricts initializers for static storage duration 4615 */ 4616 bool 4617 constant_addr(const tnode_t *tn, const sym_t **symp, ptrdiff_t *offsp) 4618 { 4619 const sym_t *sym; 4620 ptrdiff_t offs1, offs2; 4621 tspec_t t, ot; 4622 4623 switch (tn->tn_op) { 4624 case MINUS: 4625 if (tn->tn_right->tn_op == CVT) 4626 return constant_addr(tn->tn_right, symp, offsp); 4627 else if (tn->tn_right->tn_op != CON) 4628 return false; 4629 /* FALLTHROUGH */ 4630 case PLUS: 4631 offs1 = offs2 = 0; 4632 if (tn->tn_left->tn_op == CON) { 4633 offs1 = (ptrdiff_t)tn->tn_left->tn_val.u.integer; 4634 if (!constant_addr(tn->tn_right, &sym, &offs2)) 4635 return false; 4636 } else if (tn->tn_right->tn_op == CON) { 4637 offs2 = (ptrdiff_t)tn->tn_right->tn_val.u.integer; 4638 if (tn->tn_op == MINUS) 4639 offs2 = -offs2; 4640 if (!constant_addr(tn->tn_left, &sym, &offs1)) 4641 return false; 4642 } else { 4643 return false; 4644 } 4645 *symp = sym; 4646 *offsp = offs1 + offs2; 4647 return true; 4648 case ADDR: 4649 if (tn->tn_left->tn_op == NAME) { 4650 *symp = tn->tn_left->tn_sym; 4651 *offsp = 0; 4652 return true; 4653 } else { 4654 /* 4655 * If this were the front end of a compiler, we would 4656 * return a label instead of 0, at least if 4657 * 'tn->tn_left->tn_op == STRING'. 4658 */ 4659 *symp = NULL; 4660 *offsp = 0; 4661 return true; 4662 } 4663 case CVT: 4664 t = tn->tn_type->t_tspec; 4665 ot = tn->tn_left->tn_type->t_tspec; 4666 if ((!is_integer(t) && t != PTR) || 4667 (!is_integer(ot) && ot != PTR)) { 4668 return false; 4669 } 4670 #if 0 4671 /*- 4672 * consider: 4673 * struct foo { 4674 * unsigned char a; 4675 * } f = { 4676 * (unsigned char)(unsigned long) 4677 * (&(((struct foo *)0)->a)) 4678 * }; 4679 * since psize(unsigned long) != psize(unsigned char), 4680 * this fails. 4681 */ 4682 else if (psize(t) != psize(ot)) 4683 return -1; 4684 #endif 4685 return constant_addr(tn->tn_left, symp, offsp); 4686 default: 4687 return false; 4688 } 4689 } 4690 4691 /* Append s2 to s1, then free s2. */ 4692 strg_t * 4693 cat_strings(strg_t *s1, strg_t *s2) 4694 { 4695 4696 if (s1->st_char != s2->st_char) { 4697 /* cannot concatenate wide and regular string literals */ 4698 error(292); 4699 return s1; 4700 } 4701 4702 size_t len1 = s1->st_len; 4703 size_t len2 = s2->st_len; 4704 size_t chsize = s1->st_char ? sizeof(char) : sizeof(wchar_t); 4705 size_t size1 = len1 * chsize; 4706 size_t size2 = (len2 + 1) * chsize; 4707 s1->st_mem = xrealloc(s1->st_mem, size1 + size2); 4708 memcpy((char *)s1->st_mem + size1, s2->st_mem, size2); 4709 free(s2->st_mem); 4710 4711 s1->st_len = len1 + len2; 4712 free(s2); 4713 4714 return s1; 4715 } 4716 4717 4718 typedef struct stmt_expr { 4719 memory_pool se_mem; 4720 sym_t *se_sym; 4721 struct stmt_expr *se_enclosing; 4722 } stmt_expr; 4723 4724 static stmt_expr *stmt_exprs; 4725 4726 void 4727 begin_statement_expr(void) 4728 { 4729 debug_enter(); 4730 4731 stmt_expr *se = xmalloc(sizeof(*se)); 4732 se->se_mem = expr_save_memory(); 4733 se->se_sym = NULL; 4734 se->se_enclosing = stmt_exprs; 4735 stmt_exprs = se; 4736 } 4737 4738 void 4739 do_statement_expr(tnode_t *tn) 4740 { 4741 block_level--; 4742 mem_block_level--; 4743 stmt_exprs->se_sym = tn != NULL 4744 ? mktempsym(block_dup_type(tn->tn_type)) 4745 : NULL; /* after a syntax error */ 4746 mem_block_level++; 4747 block_level++; 4748 /* '({ ... })' is a GCC extension */ 4749 gnuism(320); 4750 } 4751 4752 tnode_t * 4753 end_statement_expr(void) 4754 { 4755 tnode_t *tn; 4756 4757 stmt_expr *se = stmt_exprs; 4758 if (se->se_sym == NULL) { 4759 tn = NULL; /* after a syntax error */ 4760 goto end; 4761 } 4762 4763 tn = build_name(se->se_sym, false); 4764 (void)expr_save_memory(); /* leak */ 4765 expr_restore_memory(se->se_mem); 4766 stmt_exprs = se->se_enclosing; 4767 free(se); 4768 4769 end: 4770 debug_leave(); 4771 return tn; 4772 } 4773 4774 bool 4775 in_statement_expr(void) 4776 { 4777 return stmt_exprs != NULL; 4778 } 4779
Indexes created Fri Oct 03 17:10:05 GMT 2025