tree.c revision 1.563
1 /* $NetBSD: tree.c,v 1.563 2023/07/13 08:40:38 rillig Exp $ */ 2 3 /* 4 * Copyright (c) 1994, 1995 Jochen Pohl 5 * All Rights Reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. All advertising materials mentioning features or use of this software 16 * must display the following acknowledgement: 17 * This product includes software developed by Jochen Pohl for 18 * The NetBSD Project. 19 * 4. The name of the author may not be used to endorse or promote products 20 * derived from this software without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 23 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 24 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 25 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 26 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 27 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 28 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 29 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 30 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 31 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 32 */ 33 34 #if HAVE_NBTOOL_CONFIG_H 35 #include "nbtool_config.h" 36 #endif 37 38 #include <sys/cdefs.h> 39 #if defined(__RCSID) 40 __RCSID("$NetBSD: tree.c,v 1.563 2023/07/13 08:40:38 rillig Exp $"); 41 #endif 42 43 #include <float.h> 44 #include <limits.h> 45 #include <math.h> 46 #include <signal.h> 47 #include <stdlib.h> 48 #include <string.h> 49 50 #include "lint1.h" 51 52 53 typedef struct integer_constraints { 54 int64_t smin; /* signed minimum */ 55 int64_t smax; /* signed maximum */ 56 uint64_t umin; /* unsigned minimum */ 57 uint64_t umax; /* unsigned maximum */ 58 uint64_t bset; /* bits that are definitely set */ 59 uint64_t bclr; /* bits that are definitely clear */ 60 } integer_constraints; 61 62 63 static uint64_t 64 u64_fill_right(uint64_t x) 65 { 66 x |= x >> 1; 67 x |= x >> 2; 68 x |= x >> 4; 69 x |= x >> 8; 70 x |= x >> 16; 71 x |= x >> 32; 72 return x; 73 } 74 75 static bool 76 str_ends_with(const char *haystack, const char *needle) 77 { 78 size_t hlen = strlen(haystack); 79 size_t nlen = strlen(needle); 80 81 return nlen <= hlen && 82 memcmp(haystack + hlen - nlen, needle, nlen) == 0; 83 } 84 85 static unsigned 86 width_in_bits(const type_t *tp) 87 { 88 89 lint_assert(is_integer(tp->t_tspec)); 90 return tp->t_bitfield 91 ? tp->t_bit_field_width 92 : size_in_bits(tp->t_tspec); 93 } 94 95 static int 96 portable_rank_cmp(tspec_t t1, tspec_t t2) { 97 const ttab_t *p1 = type_properties(t1), *p2 = type_properties(t2); 98 lint_assert(p1->tt_rank_kind == p2->tt_rank_kind); 99 lint_assert(p1->tt_rank_value > 0); 100 lint_assert(p2->tt_rank_value > 0); 101 return (int)p1->tt_rank_value - (int)p2->tt_rank_value; 102 } 103 104 static bool 105 ic_maybe_signed(const type_t *tp, const integer_constraints *ic) 106 { 107 return !is_uinteger(tp->t_tspec) && ic->bclr >> 63 == 0; 108 } 109 110 static integer_constraints 111 ic_any(const type_t *tp) 112 { 113 integer_constraints c; 114 115 uint64_t vbits = value_bits(width_in_bits(tp)); 116 if (is_uinteger(tp->t_tspec)) { 117 c.smin = INT64_MIN; 118 c.smax = INT64_MAX; 119 c.umin = 0; 120 c.umax = vbits; 121 c.bset = 0; 122 c.bclr = ~c.umax; 123 } else { 124 c.smin = (int64_t)-1 - (int64_t)(vbits >> 1); 125 c.smax = (int64_t)(vbits >> 1); 126 c.umin = 0; 127 c.umax = UINT64_MAX; 128 c.bset = 0; 129 c.bclr = 0; 130 } 131 return c; 132 } 133 134 static integer_constraints 135 ic_con(const type_t *tp, const val_t *v) 136 { 137 integer_constraints c; 138 139 lint_assert(is_integer(tp->t_tspec)); 140 int64_t si = v->u.integer; 141 uint64_t ui = (uint64_t)si; 142 c.smin = si; 143 c.smax = si; 144 c.umin = ui; 145 c.umax = ui; 146 c.bset = ui; 147 c.bclr = ~ui; 148 return c; 149 } 150 151 static integer_constraints 152 ic_cvt(const type_t *ntp, const type_t *otp, integer_constraints a) 153 { 154 unsigned nw = width_in_bits(ntp); 155 unsigned ow = width_in_bits(otp); 156 bool nu = is_uinteger(ntp->t_tspec); 157 bool ou = is_uinteger(otp->t_tspec); 158 159 if (nw >= ow && nu == ou) 160 return a; 161 if (nw > ow && ou) 162 return a; 163 return ic_any(ntp); 164 } 165 166 static integer_constraints 167 ic_bitand(integer_constraints a, integer_constraints b) 168 { 169 integer_constraints c; 170 171 c.smin = INT64_MIN; 172 c.smax = INT64_MAX; 173 c.umin = 0; 174 c.umax = UINT64_MAX; 175 c.bset = a.bset & b.bset; 176 c.bclr = a.bclr | b.bclr; 177 return c; 178 } 179 180 static integer_constraints 181 ic_bitor(integer_constraints a, integer_constraints b) 182 { 183 integer_constraints c; 184 185 c.smin = INT64_MIN; 186 c.smax = INT64_MAX; 187 c.umin = 0; 188 c.umax = UINT64_MAX; 189 c.bset = a.bset | b.bset; 190 c.bclr = a.bclr & b.bclr; 191 return c; 192 } 193 194 static integer_constraints 195 ic_mod(const type_t *tp, integer_constraints a, integer_constraints b) 196 { 197 integer_constraints c; 198 199 if (ic_maybe_signed(tp, &a) || ic_maybe_signed(tp, &b)) 200 return ic_any(tp); 201 202 c.smin = INT64_MIN; 203 c.smax = INT64_MAX; 204 c.umin = 0; 205 c.umax = b.umax - 1; 206 c.bset = 0; 207 c.bclr = ~u64_fill_right(c.umax); 208 return c; 209 } 210 211 static integer_constraints 212 ic_shl(const type_t *tp, integer_constraints a, integer_constraints b) 213 { 214 integer_constraints c; 215 unsigned int amount; 216 217 if (ic_maybe_signed(tp, &a)) 218 return ic_any(tp); 219 220 if (b.smin == b.smax && b.smin >= 0 && b.smin < 64) 221 amount = (unsigned int)b.smin; 222 else if (b.umin == b.umax && b.umin < 64) 223 amount = (unsigned int)b.umin; 224 else 225 return ic_any(tp); 226 227 c.smin = INT64_MIN; 228 c.smax = INT64_MAX; 229 c.umin = 0; 230 c.umax = UINT64_MAX; 231 c.bset = a.bset << amount; 232 c.bclr = a.bclr << amount | (((uint64_t)1 << amount) - 1); 233 return c; 234 } 235 236 static integer_constraints 237 ic_shr(const type_t *tp, integer_constraints a, integer_constraints b) 238 { 239 integer_constraints c; 240 unsigned int amount; 241 242 if (ic_maybe_signed(tp, &a)) 243 return ic_any(tp); 244 245 if (b.smin == b.smax && b.smin >= 0 && b.smin < 64) 246 amount = (unsigned int)b.smin; 247 else if (b.umin == b.umax && b.umin < 64) 248 amount = (unsigned int)b.umin; 249 else 250 return ic_any(tp); 251 252 c.smin = INT64_MIN; 253 c.smax = INT64_MAX; 254 c.umin = 0; 255 c.umax = UINT64_MAX; 256 c.bset = a.bset >> amount; 257 c.bclr = a.bclr >> amount | ~(~(uint64_t)0 >> amount); 258 return c; 259 } 260 261 static integer_constraints 262 ic_cond(integer_constraints a, integer_constraints b) 263 { 264 integer_constraints c; 265 266 c.smin = a.smin < b.smin ? a.smin : b.smin; 267 c.smax = a.smax > b.smax ? a.smax : b.smax; 268 c.umin = a.umin < b.umin ? a.umin : b.umin; 269 c.umax = a.umax > b.umax ? a.umax : b.umax; 270 c.bset = a.bset | b.bset; 271 c.bclr = a.bclr & b.bclr; 272 return c; 273 } 274 275 static integer_constraints 276 ic_expr(const tnode_t *tn) 277 { 278 integer_constraints lc, rc; 279 280 lint_assert(is_integer(tn->tn_type->t_tspec)); 281 282 switch (tn->tn_op) { 283 case CON: 284 return ic_con(tn->tn_type, &tn->tn_val); 285 case CVT: 286 if (!is_integer(tn->tn_left->tn_type->t_tspec)) 287 return ic_any(tn->tn_type); 288 lc = ic_expr(tn->tn_left); 289 return ic_cvt(tn->tn_type, tn->tn_left->tn_type, lc); 290 case MOD: 291 lc = ic_expr(before_conversion(tn->tn_left)); 292 rc = ic_expr(before_conversion(tn->tn_right)); 293 return ic_mod(tn->tn_type, lc, rc); 294 case SHL: 295 lc = ic_expr(tn->tn_left); 296 rc = ic_expr(tn->tn_right); 297 return ic_shl(tn->tn_type, lc, rc); 298 case SHR: 299 lc = ic_expr(tn->tn_left); 300 rc = ic_expr(tn->tn_right); 301 return ic_shr(tn->tn_type, lc, rc); 302 case BITAND: 303 lc = ic_expr(tn->tn_left); 304 rc = ic_expr(tn->tn_right); 305 return ic_bitand(lc, rc); 306 case BITOR: 307 lc = ic_expr(tn->tn_left); 308 rc = ic_expr(tn->tn_right); 309 return ic_bitor(lc, rc); 310 case QUEST: 311 lc = ic_expr(tn->tn_right->tn_left); 312 rc = ic_expr(tn->tn_right->tn_right); 313 return ic_cond(lc, rc); 314 default: 315 return ic_any(tn->tn_type); 316 } 317 } 318 319 /* Build 'pointer to tp', 'array of tp' or 'function returning tp'. */ 320 type_t * 321 block_derive_type(type_t *tp, tspec_t t) 322 { 323 type_t *tp2; 324 325 tp2 = block_zero_alloc(sizeof(*tp2)); 326 tp2->t_tspec = t; 327 tp2->t_subt = tp; 328 return tp2; 329 } 330 331 /* 332 * Derive 'pointer to tp' or 'function returning tp'. 333 * The memory is freed at the end of the current expression. 334 */ 335 type_t * 336 expr_derive_type(type_t *tp, tspec_t t) 337 { 338 type_t *tp2; 339 340 tp2 = expr_zero_alloc(sizeof(*tp2)); 341 tp2->t_tspec = t; 342 tp2->t_subt = tp; 343 return tp2; 344 } 345 346 /* 347 * Build and initialize a new node. 348 */ 349 static tnode_t * 350 new_tnode(op_t op, bool sys, type_t *type, tnode_t *ln, tnode_t *rn) 351 { 352 353 tnode_t *ntn = expr_alloc_tnode(); 354 ntn->tn_op = op; 355 ntn->tn_type = type; 356 ntn->tn_sys = sys; 357 ntn->tn_left = ln; 358 ntn->tn_right = rn; 359 360 if (op == INDIR || op == FSEL) { 361 lint_assert(ln->tn_type->t_tspec == PTR); 362 tspec_t t = ln->tn_type->t_subt->t_tspec; 363 if (t != FUNC && t != VOID) 364 ntn->tn_lvalue = true; 365 } 366 367 return ntn; 368 } 369 370 /* 371 * Create a node for a constant. 372 */ 373 tnode_t * 374 build_constant(type_t *tp, val_t *v) 375 { 376 377 tnode_t *n = expr_alloc_tnode(); 378 n->tn_op = CON; 379 n->tn_type = tp; 380 n->tn_val = *v; 381 n->tn_val.v_tspec = tp->t_tspec; 382 free(v); 383 return n; 384 } 385 386 static tnode_t * 387 build_integer_constant(tspec_t t, int64_t si) 388 { 389 390 tnode_t *n = expr_alloc_tnode(); 391 n->tn_op = CON; 392 n->tn_type = gettyp(t); 393 n->tn_val.v_tspec = t; 394 n->tn_val.v_unsigned_since_c90 = false; 395 n->tn_val.v_char_constant = false; 396 n->tn_val.u.integer = si; 397 return n; 398 } 399 400 static void 401 fallback_symbol(sym_t *sym) 402 { 403 404 if (Tflag && fallback_symbol_strict_bool(sym)) 405 return; 406 407 if (block_level > 0 && (strcmp(sym->s_name, "__FUNCTION__") == 0 || 408 strcmp(sym->s_name, "__PRETTY_FUNCTION__") == 0)) { 409 /* __FUNCTION__/__PRETTY_FUNCTION__ is a GCC extension */ 410 gnuism(316); 411 sym->s_type = block_derive_type(gettyp(CHAR), PTR); 412 sym->s_type->t_const = true; 413 return; 414 } 415 416 if (block_level > 0 && strcmp(sym->s_name, "__func__") == 0) { 417 if (!allow_c99) 418 /* __func__ is a C99 feature */ 419 warning(317); 420 /* C11 6.4.2.2 */ 421 sym->s_type = block_derive_type(gettyp(CHAR), ARRAY); 422 sym->s_type->t_const = true; 423 sym->s_type->t_dim = (int)strlen(funcsym->s_name) + 1; 424 return; 425 } 426 427 /* '%s' undefined */ 428 error(99, sym->s_name); 429 } 430 431 /* 432 * Functions that are predeclared by GCC or other compilers can be called 433 * with arbitrary arguments. Since lint usually runs after a successful 434 * compilation, it's the compiler's job to catch any errors. 435 */ 436 bool 437 is_compiler_builtin(const char *name) 438 { 439 /* https://gcc.gnu.org/onlinedocs/gcc/C-Extensions.html */ 440 if (allow_gcc) { 441 if (strncmp(name, "__atomic_", 9) == 0 || 442 strncmp(name, "__builtin_", 10) == 0 || 443 strcmp(name, "alloca") == 0 || 444 /* obsolete but still in use, as of 2021 */ 445 strncmp(name, "__sync_", 7) == 0) 446 return true; 447 } 448 449 /* https://software.intel.com/sites/landingpage/IntrinsicsGuide/ */ 450 if (strncmp(name, "_mm_", 4) == 0) 451 return true; 452 453 return false; 454 } 455 456 /* https://gcc.gnu.org/onlinedocs/gcc/Integer-Overflow-Builtins.html */ 457 static bool 458 is_gcc_bool_builtin(const char *name) 459 { 460 return strncmp(name, "__builtin_", 10) == 0 && 461 (str_ends_with(name, "_overflow") || 462 str_ends_with(name, "_overflow_p")); 463 } 464 465 static void 466 build_name_call(sym_t *sym) 467 { 468 469 if (is_compiler_builtin(sym->s_name)) { 470 /* 471 * Do not warn about these, just assume that 472 * they are regular functions compatible with 473 * non-prototype calling conventions. 474 */ 475 if (allow_gcc && is_gcc_bool_builtin(sym->s_name)) 476 sym->s_type = gettyp(BOOL); 477 } else if (allow_c99) { 478 /* function '%s' implicitly declared to return int */ 479 error(215, sym->s_name); 480 } else if (!allow_trad) { 481 /* function '%s' implicitly declared to return int */ 482 warning(215, sym->s_name); 483 } 484 485 /* XXX if !allow_c90, the symbol should be exported to level 0 */ 486 sym->s_type = block_derive_type(sym->s_type, FUNC); 487 } 488 489 /* Create a node for a name (symbol table entry). */ 490 tnode_t * 491 build_name(sym_t *sym, bool is_funcname) 492 { 493 494 if (sym->s_scl == NOSCL && !in_gcc_attribute) { 495 sym->s_scl = EXTERN; 496 sym->s_def = DECL; 497 if (is_funcname) 498 build_name_call(sym); 499 else 500 fallback_symbol(sym); 501 } 502 503 lint_assert(sym->s_kind == FVFT || sym->s_kind == FMEMBER); 504 505 tnode_t *n = expr_alloc_tnode(); 506 n->tn_type = sym->s_type; 507 if (sym->s_scl == BOOL_CONST) { 508 n->tn_op = CON; 509 n->tn_val.v_tspec = BOOL; 510 n->tn_val.v_unsigned_since_c90 = false; 511 n->tn_val.v_char_constant = false; 512 n->tn_val.u.integer = sym->u.s_bool_constant ? 1 : 0; 513 } else if (sym->s_scl == ENUM_CONST) { 514 n->tn_op = CON; 515 n->tn_val.v_tspec = INT; /* ENUM is in n->tn_type */ 516 n->tn_val.v_unsigned_since_c90 = false; 517 n->tn_val.v_char_constant = false; 518 n->tn_val.u.integer = sym->u.s_enum_constant; 519 } else { 520 n->tn_op = NAME; 521 n->tn_sym = sym; 522 if (sym->s_kind == FVFT && sym->s_type->t_tspec != FUNC) 523 n->tn_lvalue = true; 524 } 525 526 return n; 527 } 528 529 tnode_t * 530 build_string(strg_t *strg) 531 { 532 size_t len = strg->st_len; 533 534 type_t *tp = expr_zero_alloc(sizeof(*tp)); 535 tp->t_tspec = ARRAY; 536 tp->t_subt = gettyp(strg->st_char ? CHAR : WCHAR_TSPEC); 537 tp->t_dim = (int)(len + 1); 538 539 tnode_t *n = expr_alloc_tnode(); 540 n->tn_op = STRING; 541 n->tn_type = tp; 542 n->tn_lvalue = true; 543 544 n->tn_string = expr_zero_alloc(sizeof(*n->tn_string)); 545 n->tn_string->st_char = strg->st_char; 546 n->tn_string->st_len = len; 547 548 size_t chsize = strg->st_char ? sizeof(char) : sizeof(wchar_t); 549 size_t size = (len + 1) * chsize; 550 n->tn_string->st_mem = expr_zero_alloc(size); 551 (void)memcpy(n->tn_string->st_mem, strg->st_mem, size); 552 free(strg->st_mem); 553 free(strg); 554 555 return n; 556 } 557 558 tnode_t * 559 build_generic_selection(const tnode_t *expr, 560 struct generic_association *sel) 561 { 562 tnode_t *default_result = NULL; 563 564 for (; sel != NULL; sel = sel->ga_prev) { 565 if (expr != NULL && 566 types_compatible(sel->ga_arg, expr->tn_type, 567 false, false, NULL)) 568 return sel->ga_result; 569 else if (sel->ga_arg == NULL) 570 default_result = sel->ga_result; 571 } 572 return default_result; 573 } 574 575 static bool 576 is_out_of_char_range(const tnode_t *tn) 577 { 578 return tn->tn_op == CON && 579 !tn->tn_val.v_char_constant && 580 !(0 <= tn->tn_val.u.integer && 581 tn->tn_val.u.integer < 1 << (CHAR_SIZE - 1)); 582 } 583 584 static void 585 check_integer_comparison(op_t op, tnode_t *ln, tnode_t *rn) 586 { 587 588 tspec_t lt = ln->tn_type->t_tspec; 589 tspec_t rt = rn->tn_type->t_tspec; 590 591 if (ln->tn_op != CON && rn->tn_op != CON) 592 return; 593 594 if (!is_integer(lt) || !is_integer(rt)) 595 return; 596 597 if (any_query_enabled && !in_system_header) { 598 if (lt == CHAR && rn->tn_op == CON && 599 !rn->tn_val.v_char_constant) { 600 /* comparison '%s' of 'char' with plain integer %d */ 601 query_message(14, 602 op_name(op), (int)rn->tn_val.u.integer); 603 } 604 if (rt == CHAR && ln->tn_op == CON && 605 !ln->tn_val.v_char_constant) { 606 /* comparison '%s' of 'char' with plain integer %d */ 607 query_message(14, 608 op_name(op), (int)ln->tn_val.u.integer); 609 } 610 } 611 612 if (hflag || pflag) { 613 if (lt == CHAR && is_out_of_char_range(rn)) { 614 char buf[128]; 615 (void)snprintf(buf, sizeof(buf), "%s %d", 616 op_name(op), (int)rn->tn_val.u.integer); 617 /* nonportable character comparison '%s' */ 618 warning(230, buf); 619 return; 620 } 621 if (rt == CHAR && is_out_of_char_range(ln)) { 622 char buf[128]; 623 (void)snprintf(buf, sizeof(buf), "%d %s ?", 624 (int)ln->tn_val.u.integer, op_name(op)); 625 /* nonportable character comparison '%s' */ 626 warning(230, buf); 627 return; 628 } 629 } 630 631 if (is_uinteger(lt) && !is_uinteger(rt) && 632 rn->tn_op == CON && rn->tn_val.u.integer <= 0) { 633 if (rn->tn_val.u.integer < 0) { 634 /* operator '%s' compares '%s' with '%s' */ 635 warning(162, op_name(op), 636 type_name(ln->tn_type), "negative constant"); 637 } else if (op == LT || op == GE) { 638 /* operator '%s' compares '%s' with '%s' */ 639 warning(162, op_name(op), type_name(ln->tn_type), "0"); 640 } 641 return; 642 } 643 if (is_uinteger(rt) && !is_uinteger(lt) && 644 ln->tn_op == CON && ln->tn_val.u.integer <= 0) { 645 if (ln->tn_val.u.integer < 0) { 646 /* operator '%s' compares '%s' with '%s' */ 647 warning(162, op_name(op), 648 "negative constant", type_name(rn->tn_type)); 649 } else if (op == GT || op == LE) { 650 /* operator '%s' compares '%s' with '%s' */ 651 warning(162, op_name(op), "0", type_name(rn->tn_type)); 652 } 653 return; 654 } 655 } 656 657 static const tspec_t arith_rank[] = { 658 LDOUBLE, DOUBLE, FLOAT, 659 #ifdef INT128_SIZE 660 UINT128, INT128, 661 #endif 662 ULLONG, LLONG, 663 ULONG, LONG, 664 UINT, INT, 665 }; 666 667 /* Keep unsigned in traditional C */ 668 static tspec_t 669 usual_arithmetic_conversion_trad(tspec_t lt, tspec_t rt) 670 { 671 672 size_t i; 673 for (i = 0; arith_rank[i] != INT; i++) 674 if (lt == arith_rank[i] || rt == arith_rank[i]) 675 break; 676 677 tspec_t t = arith_rank[i]; 678 if (is_uinteger(lt) || is_uinteger(rt)) 679 if (is_integer(t) && !is_uinteger(t)) 680 return unsigned_type(t); 681 return t; 682 } 683 684 static tspec_t 685 usual_arithmetic_conversion_c90(tspec_t lt, tspec_t rt) 686 { 687 688 if (lt == rt) 689 return lt; 690 691 if (lt == LCOMPLEX || rt == LCOMPLEX) 692 return LCOMPLEX; 693 if (lt == DCOMPLEX || rt == DCOMPLEX) 694 return DCOMPLEX; 695 if (lt == FCOMPLEX || rt == FCOMPLEX) 696 return FCOMPLEX; 697 if (lt == LDOUBLE || rt == LDOUBLE) 698 return LDOUBLE; 699 if (lt == DOUBLE || rt == DOUBLE) 700 return DOUBLE; 701 if (lt == FLOAT || rt == FLOAT) 702 return FLOAT; 703 704 /* 705 * If type A has more bits than type B, it should be able to hold all 706 * possible values of type B. 707 */ 708 if (size_in_bits(lt) > size_in_bits(rt)) 709 return lt; 710 if (size_in_bits(lt) < size_in_bits(rt)) 711 return rt; 712 713 size_t i; 714 for (i = 3; arith_rank[i] != INT; i++) 715 if (arith_rank[i] == lt || arith_rank[i] == rt) 716 break; 717 if ((is_uinteger(lt) || is_uinteger(rt)) && 718 !is_uinteger(arith_rank[i])) 719 i--; 720 return arith_rank[i]; 721 } 722 723 static tnode_t * 724 apply_usual_arithmetic_conversions(op_t op, tnode_t *tn, tspec_t t) 725 { 726 type_t *ntp = expr_dup_type(tn->tn_type); 727 ntp->t_tspec = t; 728 if (tn->tn_op != CON) { 729 /* usual arithmetic conversion for '%s' from '%s' to '%s' */ 730 query_message(4, op_name(op), 731 type_name(tn->tn_type), type_name(ntp)); 732 } 733 return convert(op, 0, ntp, tn); 734 } 735 736 /* 737 * Apply the "usual arithmetic conversions" (C99 6.3.1.8), which gives both 738 * operands the same type. 739 */ 740 static void 741 balance(op_t op, tnode_t **lnp, tnode_t **rnp) 742 { 743 744 tspec_t lt = (*lnp)->tn_type->t_tspec; 745 tspec_t rt = (*rnp)->tn_type->t_tspec; 746 if (!is_arithmetic(lt) || !is_arithmetic(rt)) 747 return; 748 749 tspec_t t = allow_c90 750 ? usual_arithmetic_conversion_c90(lt, rt) 751 : usual_arithmetic_conversion_trad(lt, rt); 752 753 if (t != lt) 754 *lnp = apply_usual_arithmetic_conversions(op, *lnp, t); 755 if (t != rt) 756 *rnp = apply_usual_arithmetic_conversions(op, *rnp, t); 757 } 758 759 /* 760 * Create a tree node for the unary & operator 761 */ 762 static tnode_t * 763 build_address(bool sys, tnode_t *tn, bool noign) 764 { 765 tspec_t t; 766 767 if (!noign && ((t = tn->tn_type->t_tspec) == ARRAY || t == FUNC)) { 768 if (!allow_c90) 769 /* '&' before array or function: ignored */ 770 warning(127); 771 return tn; 772 } 773 774 /* eliminate &* */ 775 if (tn->tn_op == INDIR && 776 tn->tn_left->tn_type->t_tspec == PTR && 777 tn->tn_left->tn_type->t_subt == tn->tn_type) { 778 return tn->tn_left; 779 } 780 781 return new_tnode(ADDR, sys, expr_derive_type(tn->tn_type, PTR), 782 tn, NULL); 783 } 784 785 /* 786 * XXX 787 * Note: There appear to be a number of bugs in detecting overflow in 788 * this function. An audit and a set of proper regression tests are needed. 789 * --Perry Metzger, Nov. 16, 2001 790 */ 791 /* 792 * Do only as much as necessary to compute constant expressions. 793 * Called only if the operator allows folding and all operands are constants. 794 */ 795 static tnode_t * 796 fold(tnode_t *tn) 797 { 798 799 val_t *v = xcalloc(1, sizeof(*v)); 800 v->v_tspec = tn->tn_type->t_tspec; 801 802 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 878 * shifts of 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 /* 935 * Create a new node for one of the operators POINT and ARROW. 936 */ 937 static tnode_t * 938 build_struct_access(op_t op, bool sys, tnode_t *ln, tnode_t *rn) 939 { 940 941 lint_assert(rn->tn_op == NAME); 942 lint_assert(is_member(rn->tn_sym)); 943 944 /* 945 * Remember if the left operand is an lvalue (structure members 946 * are lvalues if and only if the structure itself is an lvalue). 947 */ 948 bool nolval = op == POINT && !ln->tn_lvalue; 949 950 if (op == POINT) { 951 ln = build_address(sys, ln, true); 952 } else if (ln->tn_type->t_tspec != PTR) { 953 lint_assert(!allow_c90); 954 lint_assert(is_integer(ln->tn_type->t_tspec)); 955 ln = convert(NOOP, 0, expr_derive_type(gettyp(VOID), PTR), ln); 956 } 957 958 tnode_t *ctn = build_integer_constant(PTRDIFF_TSPEC, 959 rn->tn_sym->u.s_member.sm_offset_in_bits / CHAR_SIZE); 960 961 type_t *ptr_tp = expr_derive_type(rn->tn_type, PTR); 962 tnode_t *ntn = new_tnode(PLUS, sys, ptr_tp, ln, ctn); 963 if (ln->tn_op == CON) 964 ntn = fold(ntn); 965 966 if (rn->tn_type->t_bitfield) { 967 ntn = new_tnode(FSEL, sys, ntn->tn_type->t_subt, ntn, NULL); 968 } else { 969 ntn = new_tnode(INDIR, sys, ntn->tn_type->t_subt, ntn, NULL); 970 } 971 972 if (nolval) 973 ntn->tn_lvalue = false; 974 975 return ntn; 976 } 977 978 /* 979 * Get the size in bytes of type tp->t_subt, as a constant expression of type 980 * ptrdiff_t as seen from the target platform. 981 */ 982 static tnode_t * 983 subt_size_in_bytes(type_t *tp) 984 { 985 986 lint_assert(tp->t_tspec == PTR); 987 tp = tp->t_subt; 988 989 int elem = 1; 990 while (tp->t_tspec == ARRAY) { 991 elem *= tp->t_dim; 992 tp = tp->t_subt; 993 } 994 995 int elsz_in_bits = 0; 996 switch (tp->t_tspec) { 997 case FUNC: 998 /* pointer to function is not allowed here */ 999 error(110); 1000 break; 1001 case VOID: 1002 /* cannot do pointer arithmetic on operand of unknown size */ 1003 gnuism(136); 1004 break; 1005 case STRUCT: 1006 case UNION: 1007 if ((elsz_in_bits = (int)tp->t_sou->sou_size_in_bits) == 0) 1008 /* cannot do pointer arithmetic on operand of ... */ 1009 error(136); 1010 break; 1011 case ENUM: 1012 if (is_incomplete(tp)) { 1013 /* cannot do pointer arithmetic on operand of ... */ 1014 warning(136); 1015 } 1016 /* FALLTHROUGH */ 1017 default: 1018 if ((elsz_in_bits = size_in_bits(tp->t_tspec)) == 0) { 1019 /* cannot do pointer arithmetic on operand of ... */ 1020 error(136); 1021 } else { 1022 lint_assert(elsz_in_bits != -1); 1023 } 1024 break; 1025 } 1026 1027 if (elem == 0 && elsz_in_bits != 0) { 1028 /* cannot do pointer arithmetic on operand of unknown size */ 1029 error(136); 1030 } 1031 1032 if (elsz_in_bits == 0) 1033 elsz_in_bits = CHAR_SIZE; 1034 1035 return build_integer_constant(PTRDIFF_TSPEC, 1036 (int64_t)(elem * elsz_in_bits / CHAR_SIZE)); 1037 } 1038 1039 /* 1040 * Create a node for INCAFT, INCBEF, DECAFT and DECBEF. 1041 */ 1042 static tnode_t * 1043 build_prepost_incdec(op_t op, bool sys, tnode_t *ln) 1044 { 1045 1046 lint_assert(ln != NULL); 1047 tnode_t *cn = ln->tn_type->t_tspec == PTR 1048 ? subt_size_in_bytes(ln->tn_type) 1049 : build_integer_constant(INT, 1); 1050 return new_tnode(op, sys, ln->tn_type, ln, cn); 1051 } 1052 1053 static void 1054 check_enum_array_index(const tnode_t *ln, const tnode_t *rn) 1055 { 1056 1057 if (ln->tn_op != ADDR || ln->tn_left->tn_op != NAME) 1058 return; 1059 1060 const type_t *ltp = ln->tn_left->tn_type; 1061 if (ltp->t_tspec != ARRAY || ltp->t_incomplete_array) 1062 return; 1063 1064 if (rn->tn_op != CVT || !rn->tn_type->t_is_enum) 1065 return; 1066 if (rn->tn_left->tn_op != LOAD) 1067 return; 1068 1069 const type_t *rtp = rn->tn_left->tn_type; 1070 const sym_t *ec = rtp->t_enum->en_first_enumerator; 1071 const sym_t *max_ec = ec; 1072 lint_assert(ec != NULL); 1073 for (ec = ec->s_next; ec != NULL; ec = ec->s_next) 1074 if (ec->u.s_enum_constant > max_ec->u.s_enum_constant) 1075 max_ec = ec; 1076 1077 int64_t max_enum_value = max_ec->u.s_enum_constant; 1078 lint_assert(INT_MIN <= max_enum_value && max_enum_value <= INT_MAX); 1079 1080 int max_array_index = ltp->t_dim - 1; 1081 if (max_enum_value == max_array_index) 1082 return; 1083 1084 /* 1085 * If the name of the largest enum constant contains 'MAX' or 'NUM', 1086 * that constant is typically not part of the allowed enum values but 1087 * a marker for the number of actual enum values. 1088 */ 1089 if (max_enum_value == max_array_index + 1 && 1090 (strstr(max_ec->s_name, "MAX") != NULL || 1091 strstr(max_ec->s_name, "max") != NULL || 1092 strstr(max_ec->s_name, "NUM") != NULL || 1093 strstr(max_ec->s_name, "num") != NULL)) 1094 return; 1095 1096 /* maximum value %d of '%s' does not match maximum array index %d */ 1097 warning(348, (int)max_enum_value, type_name(rtp), max_array_index); 1098 print_previous_declaration(max_ec); 1099 } 1100 1101 /* 1102 * Create a node for operators PLUS and MINUS. 1103 */ 1104 static tnode_t * 1105 build_plus_minus(op_t op, bool sys, tnode_t *ln, tnode_t *rn) 1106 { 1107 1108 /* If pointer and integer, move the pointer to the left. */ 1109 if (rn->tn_type->t_tspec == PTR && is_integer(ln->tn_type->t_tspec)) { 1110 tnode_t *tmp = ln; 1111 ln = rn; 1112 rn = tmp; 1113 /* pointer addition has integer on the left-hand side */ 1114 query_message(5); 1115 } 1116 1117 /* pointer +- integer */ 1118 if (ln->tn_type->t_tspec == PTR && rn->tn_type->t_tspec != PTR) { 1119 lint_assert(is_integer(rn->tn_type->t_tspec)); 1120 1121 check_ctype_macro_invocation(ln, rn); 1122 check_enum_array_index(ln, rn); 1123 1124 tnode_t *elsz = subt_size_in_bytes(ln->tn_type); 1125 if (rn->tn_type->t_tspec != elsz->tn_type->t_tspec) 1126 rn = convert(NOOP, 0, elsz->tn_type, rn); 1127 1128 tnode_t *prod = new_tnode(MULT, sys, rn->tn_type, rn, elsz); 1129 if (rn->tn_op == CON) 1130 prod = fold(prod); 1131 1132 return new_tnode(op, sys, ln->tn_type, ln, prod); 1133 } 1134 1135 /* pointer - pointer */ 1136 if (rn->tn_type->t_tspec == PTR) { 1137 lint_assert(ln->tn_type->t_tspec == PTR); 1138 lint_assert(op == MINUS); 1139 1140 type_t *ptrdiff = gettyp(PTRDIFF_TSPEC); 1141 tnode_t *raw_diff = new_tnode(op, sys, ptrdiff, ln, rn); 1142 if (ln->tn_op == CON && rn->tn_op == CON) 1143 raw_diff = fold(raw_diff); 1144 1145 tnode_t *elsz = subt_size_in_bytes(ln->tn_type); 1146 balance(NOOP, &raw_diff, &elsz); 1147 1148 return new_tnode(DIV, sys, ptrdiff, raw_diff, elsz); 1149 } 1150 1151 return new_tnode(op, sys, ln->tn_type, ln, rn); 1152 } 1153 1154 /* 1155 * Create a node for operators SHL and SHR. 1156 */ 1157 static tnode_t * 1158 build_bit_shift(op_t op, bool sys, tnode_t *ln, tnode_t *rn) 1159 { 1160 1161 if (!allow_c90 && rn->tn_type->t_tspec != INT) 1162 rn = convert(NOOP, 0, gettyp(INT), rn); 1163 return new_tnode(op, sys, ln->tn_type, ln, rn); 1164 } 1165 1166 static bool 1167 is_null_pointer(const tnode_t *tn) 1168 { 1169 tspec_t t = tn->tn_type->t_tspec; 1170 1171 return ((t == PTR && tn->tn_type->t_subt->t_tspec == VOID) || 1172 is_integer(t)) 1173 && (tn->tn_op == CON && tn->tn_val.u.integer == 0); 1174 } 1175 1176 /* Return a type based on tp1, with added qualifiers from tp2. */ 1177 static type_t * 1178 merge_qualifiers(type_t *tp1, const type_t *tp2) 1179 { 1180 1181 lint_assert(tp1->t_tspec == PTR); 1182 lint_assert(tp2->t_tspec == PTR); 1183 1184 bool c1 = tp1->t_subt->t_const; 1185 bool c2 = tp2->t_subt->t_const; 1186 bool v1 = tp1->t_subt->t_volatile; 1187 bool v2 = tp2->t_subt->t_volatile; 1188 1189 if (c1 == (c1 | c2) && v1 == (v1 | v2)) 1190 return tp1; 1191 1192 type_t *nstp = expr_dup_type(tp1->t_subt); 1193 nstp->t_const |= c2; 1194 nstp->t_volatile |= v2; 1195 1196 type_t *ntp = expr_dup_type(tp1); 1197 ntp->t_subt = nstp; 1198 return ntp; 1199 } 1200 1201 /* See C99 6.5.15 "Conditional operator". */ 1202 static tnode_t * 1203 build_colon(bool sys, tnode_t *ln, tnode_t *rn) 1204 { 1205 1206 tspec_t lt = ln->tn_type->t_tspec; 1207 tspec_t rt = rn->tn_type->t_tspec; 1208 1209 type_t *tp; 1210 if (is_arithmetic(lt) && is_arithmetic(rt)) { 1211 /* The operands were already balanced in build_binary. */ 1212 tp = ln->tn_type; 1213 } else if (lt == BOOL && rt == BOOL) { 1214 tp = ln->tn_type; 1215 } else if (lt == VOID || rt == VOID) { 1216 tp = gettyp(VOID); 1217 } else if (is_struct_or_union(lt)) { 1218 /* Both types must be identical. */ 1219 lint_assert(is_struct_or_union(rt)); 1220 lint_assert(ln->tn_type->t_sou == rn->tn_type->t_sou); 1221 if (is_incomplete(ln->tn_type)) { 1222 /* unknown operand size, op '%s' */ 1223 error(138, op_name(COLON)); 1224 return NULL; 1225 } 1226 tp = ln->tn_type; 1227 } else if (lt == PTR && is_integer(rt)) { 1228 if (rt != PTRDIFF_TSPEC) 1229 rn = convert(NOOP, 0, gettyp(PTRDIFF_TSPEC), rn); 1230 tp = ln->tn_type; 1231 } else if (rt == PTR && is_integer(lt)) { 1232 if (lt != PTRDIFF_TSPEC) 1233 ln = convert(NOOP, 0, gettyp(PTRDIFF_TSPEC), ln); 1234 tp = rn->tn_type; 1235 } else if (lt == PTR && is_null_pointer(rn)) { 1236 tp = merge_qualifiers(ln->tn_type, rn->tn_type); 1237 } else if (rt == PTR && is_null_pointer(ln)) { 1238 tp = merge_qualifiers(rn->tn_type, ln->tn_type); 1239 } else if (lt == PTR && ln->tn_type->t_subt->t_tspec == VOID) { 1240 tp = merge_qualifiers(ln->tn_type, rn->tn_type); 1241 } else if (rt == PTR && rn->tn_type->t_subt->t_tspec == VOID) { 1242 tp = merge_qualifiers(rn->tn_type, ln->tn_type); 1243 } else { 1244 /* 1245 * XXX For now we simply take the left type. This is 1246 * probably wrong, if one type contains a function prototype 1247 * and the other one, at the same place, only an old-style 1248 * declaration. 1249 */ 1250 tp = merge_qualifiers(ln->tn_type, rn->tn_type); 1251 } 1252 1253 return new_tnode(COLON, sys, tp, ln, rn); 1254 } 1255 1256 /* TODO: check for varargs */ 1257 static bool 1258 is_cast_redundant(const tnode_t *tn) 1259 { 1260 const type_t *ntp = tn->tn_type, *otp = tn->tn_left->tn_type; 1261 tspec_t nt = ntp->t_tspec, ot = otp->t_tspec; 1262 1263 if (nt == BOOL || ot == BOOL) 1264 return nt == BOOL && ot == BOOL; 1265 1266 if (is_integer(nt) && is_integer(ot)) { 1267 unsigned int nw = width_in_bits(ntp), ow = width_in_bits(otp); 1268 if (is_uinteger(nt) == is_uinteger(ot)) 1269 return nw >= ow; 1270 return is_uinteger(ot) && nw > ow; 1271 } 1272 1273 if (is_complex(nt) || is_complex(ot)) 1274 return is_complex(nt) && is_complex(ot) && 1275 size_in_bits(nt) >= size_in_bits(ot); 1276 1277 if (is_floating(nt) && is_floating(ot)) 1278 return size_in_bits(nt) >= size_in_bits(ot); 1279 1280 if (nt == PTR && ot == PTR) { 1281 if (!ntp->t_subt->t_const && otp->t_subt->t_const) 1282 return false; 1283 if (!ntp->t_subt->t_volatile && otp->t_subt->t_volatile) 1284 return false; 1285 1286 if (ntp->t_subt->t_tspec == VOID || 1287 otp->t_subt->t_tspec == VOID || 1288 types_compatible(ntp->t_subt, otp->t_subt, 1289 false, false, NULL)) 1290 return true; 1291 } 1292 1293 return false; 1294 } 1295 1296 static bool 1297 is_assignment(op_t op) 1298 { 1299 1300 return op == ASSIGN || 1301 op == MULASS || 1302 op == DIVASS || 1303 op == MODASS || 1304 op == ADDASS || 1305 op == SUBASS || 1306 op == SHLASS || 1307 op == SHRASS || 1308 op == ANDASS || 1309 op == XORASS || 1310 op == ORASS || 1311 op == RETURN || 1312 op == INIT; 1313 } 1314 1315 /* Create a node for an assignment operator (both '=' and 'op='). */ 1316 static tnode_t * 1317 build_assignment(op_t op, bool sys, tnode_t *ln, tnode_t *rn) 1318 { 1319 1320 tspec_t lt = ln->tn_type->t_tspec; 1321 tspec_t rt = rn->tn_type->t_tspec; 1322 1323 if (any_query_enabled && is_assignment(rn->tn_op)) { 1324 /* chained assignment with '%s' and '%s' */ 1325 query_message(10, op_name(op), op_name(rn->tn_op)); 1326 } 1327 1328 if ((op == ADDASS || op == SUBASS) && lt == PTR) { 1329 lint_assert(is_integer(rt)); 1330 tnode_t *ctn = subt_size_in_bytes(ln->tn_type); 1331 if (rn->tn_type->t_tspec != ctn->tn_type->t_tspec) 1332 rn = convert(NOOP, 0, ctn->tn_type, rn); 1333 rn = new_tnode(MULT, sys, rn->tn_type, rn, ctn); 1334 if (rn->tn_left->tn_op == CON) 1335 rn = fold(rn); 1336 } 1337 1338 if ((op == ASSIGN || op == RETURN || op == INIT) && 1339 (lt == STRUCT || rt == STRUCT)) { 1340 lint_assert(lt == rt); 1341 lint_assert(ln->tn_type->t_sou == rn->tn_type->t_sou); 1342 if (is_incomplete(ln->tn_type)) { 1343 if (op == RETURN) { 1344 /* cannot return incomplete type */ 1345 error(212); 1346 } else { 1347 /* unknown operand size, op '%s' */ 1348 error(138, op_name(op)); 1349 } 1350 return NULL; 1351 } 1352 } 1353 1354 if (op == SHLASS && hflag && allow_trad && allow_c90 1355 && portable_rank_cmp(lt, rt) < 0) 1356 /* semantics of '%s' change in ANSI C; ... */ 1357 warning(118, "<<="); 1358 1359 if (op != SHLASS && op != SHRASS 1360 && (op == ASSIGN || lt != PTR) 1361 && (lt != rt || (ln->tn_type->t_bitfield && rn->tn_op == CON))) { 1362 rn = convert(op, 0, ln->tn_type, rn); 1363 rt = lt; 1364 } 1365 1366 if (any_query_enabled && rn->tn_op == CVT && rn->tn_cast && 1367 types_compatible(ln->tn_type, rn->tn_type, false, false, NULL) && 1368 is_cast_redundant(rn)) { 1369 /* redundant cast from '%s' to '%s' before assignment */ 1370 query_message(7, 1371 type_name(rn->tn_left->tn_type), type_name(rn->tn_type)); 1372 } 1373 1374 return new_tnode(op, sys, ln->tn_type, ln, rn); 1375 } 1376 1377 /* 1378 * Create a node for REAL, IMAG 1379 */ 1380 static tnode_t * 1381 build_real_imag(op_t op, bool sys, tnode_t *ln) 1382 { 1383 1384 lint_assert(ln != NULL); 1385 if (ln->tn_op == NAME) { 1386 /* 1387 * This may be too much, but it avoids wrong warnings. 1388 * See d_c99_complex_split.c. 1389 */ 1390 mark_as_used(ln->tn_sym, false, false); 1391 mark_as_set(ln->tn_sym); 1392 } 1393 1394 tspec_t t; 1395 switch (ln->tn_type->t_tspec) { 1396 case LCOMPLEX: 1397 t = LDOUBLE; 1398 break; 1399 case DCOMPLEX: 1400 t = DOUBLE; 1401 break; 1402 case FCOMPLEX: 1403 t = FLOAT; 1404 break; 1405 default: 1406 /* '__%s__' is illegal for type '%s' */ 1407 error(276, op == REAL ? "real" : "imag", 1408 type_name(ln->tn_type)); 1409 return NULL; 1410 } 1411 1412 tnode_t *ntn = new_tnode(op, sys, gettyp(t), ln, NULL); 1413 ntn->tn_lvalue = true; 1414 return ntn; 1415 } 1416 1417 static bool 1418 is_confusing_precedence(op_t op, op_t lop, bool lparen, op_t rop, bool rparen) 1419 { 1420 1421 if (op == SHL || op == SHR) { 1422 if (!lparen && (lop == PLUS || lop == MINUS)) 1423 return true; 1424 if (!rparen && (rop == PLUS || rop == MINUS)) 1425 return true; 1426 return false; 1427 } 1428 1429 if (op == LOGOR) { 1430 if (!lparen && lop == LOGAND) 1431 return true; 1432 if (!rparen && rop == LOGAND) 1433 return true; 1434 return false; 1435 } 1436 1437 lint_assert(op == BITAND || op == BITXOR || op == BITOR); 1438 if (!lparen && lop != op) { 1439 if (lop == PLUS || lop == MINUS) 1440 return true; 1441 if (lop == BITAND || lop == BITXOR) 1442 return true; 1443 } 1444 if (!rparen && rop != op) { 1445 if (rop == PLUS || rop == MINUS) 1446 return true; 1447 if (rop == BITAND || rop == BITXOR) 1448 return true; 1449 } 1450 return false; 1451 } 1452 1453 /* 1454 * Print a warning if the given node has operands which should be 1455 * parenthesized. 1456 * 1457 * XXX Does not work if an operand is a constant expression. Constant 1458 * expressions are already folded. 1459 */ 1460 static void 1461 check_precedence_confusion(tnode_t *tn) 1462 { 1463 tnode_t *ln, *rn; 1464 1465 if (!hflag) 1466 return; 1467 1468 debug_node(tn); 1469 1470 lint_assert(is_binary(tn)); 1471 for (ln = tn->tn_left; ln->tn_op == CVT; ln = ln->tn_left) 1472 continue; 1473 for (rn = tn->tn_right; rn->tn_op == CVT; rn = rn->tn_left) 1474 continue; 1475 1476 if (is_confusing_precedence(tn->tn_op, 1477 ln->tn_op, ln->tn_parenthesized, 1478 rn->tn_op, rn->tn_parenthesized)) { 1479 /* precedence confusion possible: parenthesize! */ 1480 warning(169); 1481 } 1482 } 1483 1484 /* 1485 * Fold constant nodes, as much as is needed for comparing the value with 0. 1486 */ 1487 static tnode_t * 1488 fold_bool(tnode_t *tn) 1489 { 1490 1491 val_t *v = xcalloc(1, sizeof(*v)); 1492 v->v_tspec = tn->tn_type->t_tspec; 1493 lint_assert(v->v_tspec == INT || (Tflag && v->v_tspec == BOOL)); 1494 1495 bool l = constant_is_nonzero(tn->tn_left); 1496 bool r = is_binary(tn) && constant_is_nonzero(tn->tn_right); 1497 1498 switch (tn->tn_op) { 1499 case NOT: 1500 if (hflag && !suppress_constcond) 1501 /* constant argument to '!' */ 1502 warning(239); 1503 v->u.integer = !l ? 1 : 0; 1504 break; 1505 case LOGAND: 1506 v->u.integer = l && r ? 1 : 0; 1507 break; 1508 case LOGOR: 1509 v->u.integer = l || r ? 1 : 0; 1510 break; 1511 default: 1512 lint_assert(/*CONSTCOND*/false); 1513 } 1514 1515 return build_constant(tn->tn_type, v); 1516 } 1517 1518 static long double 1519 floating_error_value(tspec_t t, long double lv) 1520 { 1521 if (t == FLOAT) 1522 return lv < 0 ? -FLT_MAX : FLT_MAX; 1523 if (t == DOUBLE) 1524 return lv < 0 ? -DBL_MAX : DBL_MAX; 1525 /* 1526 * When NetBSD is cross-built in MKLINT=yes mode on x86_64 for 1527 * sparc64, tools/lint checks this code while building usr.bin/xlint. 1528 * In that situation, lint uses the preprocessor for sparc64, in which 1529 * the type 'long double' is IEEE-754-binary128, affecting the macro 1530 * LDBL_MAX below. The type 'long double', as well as the strtold 1531 * implementation, comes from the host platform x86_64 though, where 1532 * 'long double' consumes 128 bits as well but only uses 80 of them. 1533 * The exponent range of the two 'long double' types is the same, but 1534 * the maximum finite value differs due to the extended precision on 1535 * sparc64. 1536 * 1537 * To properly handle the data types of the target platform, lint 1538 * would have to implement the floating-point types in a 1539 * platform-independent way, which is not worth the effort, given how 1540 * few programs practically use 'long double'. 1541 */ 1542 /* LINTED 248: floating-point constant out of range */ 1543 long double max = LDBL_MAX; 1544 return lv < 0 ? -max : max; 1545 } 1546 1547 static bool 1548 is_floating_overflow(tspec_t t, long double val) 1549 { 1550 if (fpe != 0 || isfinite(val) == 0) 1551 return true; 1552 if (t == FLOAT && (val > FLT_MAX || val < -FLT_MAX)) 1553 return true; 1554 if (t == DOUBLE && (val > DBL_MAX || val < -DBL_MAX)) 1555 return true; 1556 return false; 1557 } 1558 1559 /* 1560 * Fold constant nodes having operands with floating point type. 1561 */ 1562 static tnode_t * 1563 fold_float(tnode_t *tn) 1564 { 1565 1566 fpe = 0; 1567 1568 tspec_t t = tn->tn_type->t_tspec; 1569 1570 val_t *v = xcalloc(1, sizeof(*v)); 1571 v->v_tspec = t; 1572 1573 lint_assert(is_floating(t)); 1574 lint_assert(t == tn->tn_left->tn_type->t_tspec); 1575 lint_assert(!is_binary(tn) || t == tn->tn_right->tn_type->t_tspec); 1576 1577 long double lv = tn->tn_left->tn_val.u.floating; 1578 long double rv = is_binary(tn) ? tn->tn_right->tn_val.u.floating : 0.0; 1579 1580 switch (tn->tn_op) { 1581 case UPLUS: 1582 v->u.floating = lv; 1583 break; 1584 case UMINUS: 1585 v->u.floating = -lv; 1586 break; 1587 case MULT: 1588 v->u.floating = lv * rv; 1589 break; 1590 case DIV: 1591 if (rv == 0.0) { 1592 /* division by 0 */ 1593 error(139); 1594 v->u.floating = floating_error_value(t, lv); 1595 } else { 1596 v->u.floating = lv / rv; 1597 } 1598 break; 1599 case PLUS: 1600 v->u.floating = lv + rv; 1601 break; 1602 case MINUS: 1603 v->u.floating = lv - rv; 1604 break; 1605 case LT: 1606 v->u.integer = lv < rv ? 1 : 0; 1607 break; 1608 case LE: 1609 v->u.integer = lv <= rv ? 1 : 0; 1610 break; 1611 case GE: 1612 v->u.integer = lv >= rv ? 1 : 0; 1613 break; 1614 case GT: 1615 v->u.integer = lv > rv ? 1 : 0; 1616 break; 1617 case EQ: 1618 v->u.integer = lv == rv ? 1 : 0; 1619 break; 1620 case NE: 1621 v->u.integer = lv != rv ? 1 : 0; 1622 break; 1623 default: 1624 lint_assert(/*CONSTCOND*/false); 1625 } 1626 1627 lint_assert(fpe != 0 || isnan(v->u.floating) == 0); 1628 if (is_complex(v->v_tspec)) { 1629 /* 1630 * Don't warn, as lint doesn't model the imaginary part of 1631 * complex numbers. 1632 */ 1633 fpe = 0; 1634 } else if (is_floating_overflow(t, v->u.floating)) { 1635 /* operator '%s' produces floating point overflow */ 1636 warning(142, op_name(tn->tn_op)); 1637 v->u.floating = floating_error_value(t, v->u.floating); 1638 fpe = 0; 1639 } 1640 1641 return build_constant(tn->tn_type, v); 1642 } 1643 1644 /* 1645 * Create a tree node for a binary operator and its two operands. Also called 1646 * for unary operators; in that case rn is NULL. 1647 * 1648 * Function calls, sizeof and casts are handled elsewhere. 1649 */ 1650 tnode_t * 1651 build_binary(tnode_t *ln, op_t op, bool sys, tnode_t *rn) 1652 { 1653 const mod_t *mp = &modtab[op]; 1654 1655 /* If there was an error in one of the operands, return. */ 1656 if (ln == NULL || (mp->m_binary && rn == NULL)) 1657 return NULL; 1658 1659 /* 1660 * Apply class conversions to the left operand, but only if its 1661 * value is needed or compared with zero. 1662 */ 1663 if (mp->m_value_context || mp->m_compares_with_zero) 1664 ln = cconv(ln); 1665 /* 1666 * The right operand is almost always in a test or value context, 1667 * except if it is a struct or union member. 1668 */ 1669 if (mp->m_binary && op != ARROW && op != POINT) 1670 rn = cconv(rn); 1671 1672 /* 1673 * Print some warnings for comparisons of unsigned values with 1674 * constants lower than or equal to null. This must be done 1675 * before promote() because otherwise unsigned char and unsigned 1676 * short would be promoted to int. Types are also tested to be 1677 * CHAR, which would also become int. 1678 */ 1679 if (mp->m_comparison) 1680 check_integer_comparison(op, ln, rn); 1681 1682 if (mp->m_value_context || mp->m_compares_with_zero) 1683 ln = promote(op, false, ln); 1684 if (mp->m_binary && op != ARROW && op != POINT && 1685 op != ASSIGN && op != RETURN && op != INIT) { 1686 rn = promote(op, false, rn); 1687 } 1688 1689 /* 1690 * If the result of the operation is different for signed or 1691 * unsigned operands and one of the operands is signed only in 1692 * ANSI C, print a warning. 1693 */ 1694 if (mp->m_warn_if_left_unsigned_in_c90 && 1695 ln->tn_op == CON && ln->tn_val.v_unsigned_since_c90) { 1696 /* ANSI C treats constant as unsigned, op '%s' */ 1697 warning(218, op_name(op)); 1698 ln->tn_val.v_unsigned_since_c90 = false; 1699 } 1700 if (mp->m_warn_if_right_unsigned_in_c90 && 1701 rn->tn_op == CON && rn->tn_val.v_unsigned_since_c90) { 1702 /* ANSI C treats constant as unsigned, op '%s' */ 1703 warning(218, op_name(op)); 1704 rn->tn_val.v_unsigned_since_c90 = false; 1705 } 1706 1707 /* Make sure both operands are of the same type */ 1708 if (mp->m_balance_operands || (!allow_c90 && (op == SHL || op == SHR))) 1709 balance(op, &ln, &rn); 1710 1711 /* 1712 * Check types for compatibility with the operation and mutual 1713 * compatibility. Return if there are serious problems. 1714 */ 1715 if (!typeok(op, 0, ln, rn)) 1716 return NULL; 1717 1718 /* And now create the node. */ 1719 tnode_t *ntn; 1720 switch (op) { 1721 case POINT: 1722 case ARROW: 1723 ntn = build_struct_access(op, sys, ln, rn); 1724 break; 1725 case INCAFT: 1726 case DECAFT: 1727 case INCBEF: 1728 case DECBEF: 1729 ntn = build_prepost_incdec(op, sys, ln); 1730 break; 1731 case ADDR: 1732 ntn = build_address(sys, ln, false); 1733 break; 1734 case INDIR: 1735 ntn = new_tnode(INDIR, sys, ln->tn_type->t_subt, ln, NULL); 1736 break; 1737 case PLUS: 1738 case MINUS: 1739 ntn = build_plus_minus(op, sys, ln, rn); 1740 break; 1741 case SHL: 1742 case SHR: 1743 ntn = build_bit_shift(op, sys, ln, rn); 1744 break; 1745 case COLON: 1746 ntn = build_colon(sys, ln, rn); 1747 break; 1748 case ASSIGN: 1749 case MULASS: 1750 case DIVASS: 1751 case MODASS: 1752 case ADDASS: 1753 case SUBASS: 1754 case SHLASS: 1755 case SHRASS: 1756 case ANDASS: 1757 case XORASS: 1758 case ORASS: 1759 case RETURN: 1760 case INIT: 1761 ntn = build_assignment(op, sys, ln, rn); 1762 break; 1763 case COMMA: 1764 if (any_query_enabled) { 1765 /* comma operator with types '%s' and '%s' */ 1766 query_message(12, 1767 type_name(ln->tn_type), type_name(rn->tn_type)); 1768 } 1769 /* FALLTHROUGH */ 1770 case QUEST: 1771 ntn = new_tnode(op, sys, rn->tn_type, ln, rn); 1772 break; 1773 case REAL: 1774 case IMAG: 1775 ntn = build_real_imag(op, sys, ln); 1776 break; 1777 default: 1778 lint_assert(mp->m_binary == (rn != NULL)); 1779 type_t *rettp = mp->m_returns_bool 1780 ? gettyp(Tflag ? BOOL : INT) : ln->tn_type; 1781 ntn = new_tnode(op, sys, rettp, ln, rn); 1782 break; 1783 } 1784 1785 /* Return if an error occurred. */ 1786 if (ntn == NULL) 1787 return NULL; 1788 1789 /* Print a warning if precedence confusion is possible */ 1790 if (mp->m_possible_precedence_confusion) 1791 check_precedence_confusion(ntn); 1792 1793 /* 1794 * Print a warning if one of the operands is in a context where 1795 * it is compared with zero and if this operand is a constant. 1796 */ 1797 if (hflag && !suppress_constcond && 1798 mp->m_compares_with_zero && 1799 (ln->tn_op == CON || 1800 ((mp->m_binary && op != QUEST) && rn->tn_op == CON)) && 1801 /* XXX: rn->tn_system_dependent should be checked as well */ 1802 !ln->tn_system_dependent) { 1803 /* constant in conditional context */ 1804 warning(161); 1805 } 1806 1807 /* Fold if the operator requires it */ 1808 if (mp->m_fold_constant_operands) { 1809 if (ln->tn_op == CON && (!mp->m_binary || rn->tn_op == CON)) { 1810 if (mp->m_compares_with_zero) { 1811 ntn = fold_bool(ntn); 1812 } else if (is_floating(ntn->tn_type->t_tspec)) { 1813 ntn = fold_float(ntn); 1814 } else { 1815 ntn = fold(ntn); 1816 } 1817 } else if (op == QUEST && ln->tn_op == CON) { 1818 ntn = ln->tn_val.u.integer != 0 1819 ? rn->tn_left : rn->tn_right; 1820 } 1821 } 1822 1823 return ntn; 1824 } 1825 1826 tnode_t * 1827 build_unary(op_t op, bool sys, tnode_t *tn) 1828 { 1829 return build_binary(tn, op, sys, NULL); 1830 } 1831 1832 static bool 1833 are_members_compatible(const sym_t *a, const sym_t *b) 1834 { 1835 if (a->u.s_member.sm_offset_in_bits != b->u.s_member.sm_offset_in_bits) 1836 return false; 1837 1838 const type_t *atp = a->s_type; 1839 const type_t *btp = b->s_type; 1840 bool w = false; 1841 if (!types_compatible(atp, btp, false, false, &w) && !w) 1842 return false; 1843 if (a->s_bitfield != b->s_bitfield) 1844 return false; 1845 if (a->s_bitfield) { 1846 if (atp->t_bit_field_width != btp->t_bit_field_width) 1847 return false; 1848 if (atp->t_bit_field_offset != btp->t_bit_field_offset) 1849 return false; 1850 } 1851 return true; 1852 } 1853 1854 /* 1855 * Return whether all struct/union members with the same name have the same 1856 * type and offset. 1857 */ 1858 static bool 1859 all_members_compatible(const sym_t *msym) 1860 { 1861 for (const sym_t *csym = msym; 1862 csym != NULL; csym = csym->s_symtab_next) { 1863 if (!is_member(csym)) 1864 continue; 1865 if (strcmp(msym->s_name, csym->s_name) != 0) 1866 continue; 1867 1868 for (const sym_t *sym = csym->s_symtab_next; 1869 sym != NULL; sym = sym->s_symtab_next) { 1870 if (is_member(sym) 1871 && strcmp(csym->s_name, sym->s_name) == 0 1872 && !are_members_compatible(csym, sym)) 1873 return false; 1874 } 1875 } 1876 return true; 1877 } 1878 1879 sym_t * 1880 find_member(const type_t *tp, const char *name) 1881 { 1882 for (sym_t *mem = tp->t_sou->sou_first_member; 1883 mem != NULL; mem = mem->s_next) { 1884 if (strcmp(mem->s_name, name) == 0) 1885 return mem; 1886 } 1887 for (sym_t *mem = tp->t_sou->sou_first_member; 1888 mem != NULL; mem = mem->s_next) { 1889 if (is_struct_or_union(mem->s_type->t_tspec) && 1890 mem->s_name == unnamed) { 1891 sym_t *nested_mem = find_member(mem->s_type, name); 1892 if (nested_mem != NULL) 1893 return nested_mem; 1894 } 1895 } 1896 return NULL; 1897 } 1898 1899 /* 1900 * Returns a symbol which has the same name as the msym argument and is a 1901 * member of the struct or union specified by the tn argument. 1902 */ 1903 static sym_t * 1904 struct_or_union_member(tnode_t *tn, op_t op, sym_t *msym) 1905 { 1906 1907 /* 1908 * Remove the member if it was unknown until now, which means 1909 * that no defined struct or union has a member with the same name. 1910 */ 1911 if (msym->s_scl == NOSCL) { 1912 /* type '%s' does not have member '%s' */ 1913 error(101, type_name(tn->tn_type), msym->s_name); 1914 rmsym(msym); 1915 msym->s_kind = FMEMBER; 1916 msym->s_scl = STRUCT_MEMBER; 1917 1918 struct_or_union *sou = expr_zero_alloc(sizeof(*sou)); 1919 sou->sou_tag = expr_zero_alloc(sizeof(*sou->sou_tag)); 1920 sou->sou_tag->s_name = unnamed; 1921 1922 msym->u.s_member.sm_containing_type = sou; 1923 /* 1924 * The member sm_offset_in_bits is not needed here since this 1925 * symbol can only be used for error reporting. 1926 */ 1927 return msym; 1928 } 1929 1930 /* Determine the tag type of which msym is expected to be a member. */ 1931 const type_t *tp = NULL; 1932 if (op == POINT && is_struct_or_union(tn->tn_type->t_tspec)) 1933 tp = tn->tn_type; 1934 if (op == ARROW && tn->tn_type->t_tspec == PTR 1935 && is_struct_or_union(tn->tn_type->t_subt->t_tspec)) 1936 tp = tn->tn_type->t_subt; 1937 struct_or_union *sou = tp != NULL ? tp->t_sou : NULL; 1938 1939 /* 1940 * If this struct/union has a member with the name of msym, return it. 1941 */ 1942 if (sou != NULL) { 1943 for (sym_t *sym = msym; 1944 sym != NULL; sym = sym->s_symtab_next) { 1945 if (is_member(sym) && 1946 sym->u.s_member.sm_containing_type == sou && 1947 strcmp(sym->s_name, msym->s_name) == 0) 1948 return sym; 1949 } 1950 } 1951 1952 if (tp != NULL) { 1953 sym_t *nested_mem = find_member(tp, msym->s_name); 1954 if (nested_mem != NULL) 1955 return nested_mem; 1956 } 1957 1958 bool eq = all_members_compatible(msym); 1959 1960 /* 1961 * Now handle the case in which the left operand refers really 1962 * to a struct/union, but the right operand is not member of it. 1963 */ 1964 if (sou != NULL) { 1965 if (eq && !allow_c90) { 1966 /* illegal use of member '%s' */ 1967 warning(102, msym->s_name); 1968 } else { 1969 /* illegal use of member '%s' */ 1970 error(102, msym->s_name); 1971 } 1972 return msym; 1973 } 1974 1975 /* 1976 * Now the left operand of ARROW does not point to a struct/union 1977 * or the left operand of POINT is no struct/union. 1978 */ 1979 if (eq) { 1980 if (op == POINT) { 1981 if (!allow_c90) { 1982 /* left operand of '.' must be struct ... */ 1983 warning(103, type_name(tn->tn_type)); 1984 } else { 1985 /* left operand of '.' must be struct ... */ 1986 error(103, type_name(tn->tn_type)); 1987 } 1988 } else { 1989 if (!allow_c90 && tn->tn_type->t_tspec == PTR) { 1990 /* left operand of '->' must be pointer ... */ 1991 warning(104, type_name(tn->tn_type)); 1992 } else { 1993 /* left operand of '->' must be pointer ... */ 1994 error(104, type_name(tn->tn_type)); 1995 } 1996 } 1997 } else { 1998 if (!allow_c90) { 1999 /* non-unique member requires struct/union %s */ 2000 error(105, op == POINT ? "object" : "pointer"); 2001 } else { 2002 /* unacceptable operand of '%s' */ 2003 error(111, op_name(op)); 2004 } 2005 } 2006 2007 return msym; 2008 } 2009 2010 tnode_t * 2011 build_member_access(tnode_t *ln, op_t op, bool sys, sbuf_t *member) 2012 { 2013 sym_t *msym; 2014 2015 if (ln == NULL) 2016 return NULL; 2017 2018 if (op == ARROW) { 2019 /* must do this before struct_or_union_member is called */ 2020 ln = cconv(ln); 2021 } 2022 msym = struct_or_union_member(ln, op, getsym(member)); 2023 return build_binary(ln, op, sys, build_name(msym, false)); 2024 } 2025 2026 /* 2027 * Perform class conversions. 2028 * 2029 * Arrays of type T are converted into pointers to type T. 2030 * Functions are converted to pointers to functions. 2031 * Lvalues are converted to rvalues. 2032 * 2033 * C99 6.3 "Conversions" 2034 * C99 6.3.2 "Other operands" 2035 * C99 6.3.2.1 "Lvalues, arrays, and function designators" 2036 */ 2037 tnode_t * 2038 cconv(tnode_t *tn) 2039 { 2040 /* 2041 * Array-lvalue (array of type T) is converted into rvalue 2042 * (pointer to type T) 2043 */ 2044 if (tn->tn_type->t_tspec == ARRAY) { 2045 if (!tn->tn_lvalue) { 2046 /* XXX print correct operator */ 2047 /* %soperand of '%s' must be lvalue */ 2048 gnuism(114, "", op_name(ADDR)); 2049 } 2050 tn = new_tnode(ADDR, tn->tn_sys, 2051 expr_derive_type(tn->tn_type->t_subt, PTR), tn, NULL); 2052 } 2053 2054 /* 2055 * Expression of type function (function with return value of type T) 2056 * in rvalue-expression (pointer to function with return value 2057 * of type T) 2058 */ 2059 if (tn->tn_type->t_tspec == FUNC) 2060 tn = build_address(tn->tn_sys, tn, true); 2061 2062 /* lvalue to rvalue */ 2063 if (tn->tn_lvalue) { 2064 type_t *tp = expr_dup_type(tn->tn_type); 2065 /* C99 6.3.2.1p2 sentence 2 says to remove the qualifiers. */ 2066 tp->t_const = tp->t_volatile = false; 2067 tn = new_tnode(LOAD, tn->tn_sys, tp, tn, NULL); 2068 } 2069 2070 return tn; 2071 } 2072 2073 const tnode_t * 2074 before_conversion(const tnode_t *tn) 2075 { 2076 while (tn->tn_op == CVT && !tn->tn_cast) 2077 tn = tn->tn_left; 2078 return tn; 2079 } 2080 2081 /* 2082 * Most errors required by ANSI C are reported in struct_or_union_member(). 2083 * Here we only check for totally wrong things. 2084 */ 2085 static bool 2086 typeok_point(const tnode_t *ln, const type_t *ltp, tspec_t lt) 2087 { 2088 if (is_struct_or_union(lt)) 2089 return true; 2090 2091 if (lt == FUNC || lt == VOID || ltp->t_bitfield) 2092 goto wrong; 2093 2094 /* 2095 * Some C dialects from before C90 tolerated any lvalue on the 2096 * left-hand side of the '.' operator, allowing things like 2097 * char st[100]; st.st_mtime, assuming that the member 'st_mtime' 2098 * only occurred in a single struct; see typeok_arrow. 2099 */ 2100 if (ln->tn_lvalue) 2101 return true; 2102 2103 wrong: 2104 /* With allow_c90 we already got an error */ 2105 if (!allow_c90) 2106 /* unacceptable operand of '%s' */ 2107 error(111, op_name(POINT)); 2108 2109 return false; 2110 } 2111 2112 static bool 2113 typeok_arrow(tspec_t lt) 2114 { 2115 /* 2116 * C1978 Appendix A 14.1 says: <quote>In fact, any lvalue is allowed 2117 * before '.', and that lvalue is then assumed to have the form of 2118 * the structure of which the name of the right is a member. [...] 2119 * Such constructions are non-portable.</quote> 2120 */ 2121 if (lt == PTR || (!allow_c90 && is_integer(lt))) 2122 return true; 2123 2124 /* With allow_c90 we already got an error */ 2125 if (!allow_c90) 2126 /* unacceptable operand of '%s' */ 2127 error(111, op_name(ARROW)); 2128 return false; 2129 } 2130 2131 static bool 2132 typeok_incdec(op_t op, const tnode_t *tn, const type_t *tp) 2133 { 2134 /* operand has scalar type (checked in typeok) */ 2135 if (!tn->tn_lvalue) { 2136 if (tn->tn_op == CVT && tn->tn_cast && 2137 tn->tn_left->tn_op == LOAD) { 2138 /* a cast does not yield an lvalue */ 2139 error(163); 2140 } 2141 /* %soperand of '%s' must be lvalue */ 2142 error(114, "", op_name(op)); 2143 return false; 2144 } 2145 if (tp->t_const && allow_c90) { 2146 /* %soperand of '%s' must be modifiable lvalue */ 2147 warning(115, "", op_name(op)); 2148 } 2149 return true; 2150 } 2151 2152 static bool 2153 typeok_address(op_t op, const tnode_t *tn, const type_t *tp, tspec_t t) 2154 { 2155 if (t == ARRAY || t == FUNC) { 2156 /* ok, a warning comes later (in build_address()) */ 2157 } else if (!tn->tn_lvalue) { 2158 if (tn->tn_op == CVT && tn->tn_cast && 2159 tn->tn_left->tn_op == LOAD) { 2160 /* a cast does not yield an lvalue */ 2161 error(163); 2162 } 2163 /* %soperand of '%s' must be lvalue */ 2164 error(114, "", op_name(op)); 2165 return false; 2166 } else if (is_scalar(t)) { 2167 if (tp->t_bitfield) { 2168 /* cannot take address of bit-field */ 2169 error(112); 2170 return false; 2171 } 2172 } else if (t != STRUCT && t != UNION) { 2173 /* unacceptable operand of '%s' */ 2174 error(111, op_name(op)); 2175 return false; 2176 } 2177 if (tn->tn_op == NAME && tn->tn_sym->s_register) { 2178 /* cannot take address of register '%s' */ 2179 error(113, tn->tn_sym->s_name); 2180 return false; 2181 } 2182 return true; 2183 } 2184 2185 static bool 2186 typeok_indir(const type_t *tp, tspec_t t) 2187 { 2188 2189 if (t != PTR) { 2190 /* cannot dereference non-pointer type '%s' */ 2191 error(96, type_name(tp)); 2192 return false; 2193 } 2194 return true; 2195 } 2196 2197 static void 2198 warn_incompatible_types(op_t op, 2199 const type_t *ltp, tspec_t lt, 2200 const type_t *rtp, tspec_t rt) 2201 { 2202 bool binary = modtab[op].m_binary; 2203 2204 if (lt == VOID || (binary && rt == VOID)) { 2205 /* void type illegal in expression */ 2206 error(109); 2207 } else if (op == ASSIGN) { 2208 /* cannot assign to '%s' from '%s' */ 2209 error(171, type_name(ltp), type_name(rtp)); 2210 } else if (binary) { 2211 /* operands of '%s' have incompatible types '%s' and '%s' */ 2212 error(107, op_name(op), type_name(ltp), type_name(rtp)); 2213 } else { 2214 lint_assert(rt == NO_TSPEC); 2215 /* operand of '%s' has invalid type '%s' */ 2216 error(108, op_name(op), type_name(ltp)); 2217 } 2218 } 2219 2220 static bool 2221 typeok_plus(op_t op, 2222 const type_t *ltp, tspec_t lt, 2223 const type_t *rtp, tspec_t rt) 2224 { 2225 /* operands have scalar types (checked in typeok) */ 2226 if ((lt == PTR && !is_integer(rt)) || (rt == PTR && !is_integer(lt))) { 2227 warn_incompatible_types(op, ltp, lt, rtp, rt); 2228 return false; 2229 } 2230 return true; 2231 } 2232 2233 static bool 2234 typeok_minus(op_t op, 2235 const type_t *ltp, tspec_t lt, 2236 const type_t *rtp, tspec_t rt) 2237 { 2238 /* operands have scalar types (checked in typeok) */ 2239 if ((lt == PTR && rt != PTR && !is_integer(rt)) || 2240 (lt != PTR && rt == PTR)) { 2241 warn_incompatible_types(op, ltp, lt, rtp, rt); 2242 return false; 2243 } 2244 if (lt == PTR && rt == PTR && 2245 !types_compatible(ltp->t_subt, rtp->t_subt, true, false, NULL)) { 2246 /* illegal pointer subtraction */ 2247 error(116); 2248 } 2249 return true; 2250 } 2251 2252 static void 2253 typeok_shr(op_t op, 2254 const tnode_t *ln, tspec_t lt, 2255 const tnode_t *rn, tspec_t rt) 2256 { 2257 tspec_t olt = before_conversion(ln)->tn_type->t_tspec; 2258 tspec_t ort = before_conversion(rn)->tn_type->t_tspec; 2259 2260 /* operands have integer types (checked in typeok) */ 2261 if (pflag && !is_uinteger(olt)) { 2262 integer_constraints lc = ic_expr(ln); 2263 if (!ic_maybe_signed(ln->tn_type, &lc)) 2264 return; 2265 2266 /* 2267 * The left operand is signed. This means that 2268 * the operation is (possibly) nonportable. 2269 */ 2270 if (ln->tn_op != CON) { 2271 /* bitwise '%s' on signed value possibly nonportable */ 2272 warning(117, op_name(op)); 2273 } else if (ln->tn_val.u.integer < 0) { 2274 /* bitwise '%s' on signed value nonportable */ 2275 warning(120, op_name(op)); 2276 } 2277 } else if (allow_trad && allow_c90 && 2278 !is_uinteger(olt) && is_uinteger(ort)) { 2279 /* The left operand would become unsigned in traditional C. */ 2280 if (hflag && (ln->tn_op != CON || ln->tn_val.u.integer < 0)) { 2281 /* semantics of '%s' change in ANSI C; use ... */ 2282 warning(118, op_name(op)); 2283 } 2284 } else if (allow_trad && allow_c90 && 2285 !is_uinteger(olt) && !is_uinteger(ort) && 2286 portable_rank_cmp(lt, rt) < 0) { 2287 /* 2288 * In traditional C the left operand would be extended 2289 * (possibly sign-extended) and then shifted. 2290 */ 2291 if (hflag && (ln->tn_op != CON || ln->tn_val.u.integer < 0)) { 2292 /* semantics of '%s' change in ANSI C; use ... */ 2293 warning(118, op_name(op)); 2294 } 2295 } 2296 } 2297 2298 static void 2299 typeok_shl(op_t op, tspec_t lt, tspec_t rt) 2300 { 2301 /* 2302 * C90 does not perform balancing for shift operations, 2303 * but traditional C does. If the width of the right operand 2304 * is greater than the width of the left operand, then in 2305 * traditional C the left operand would be extended to the 2306 * width of the right operand. For SHL this may result in 2307 * different results. 2308 */ 2309 if (portable_rank_cmp(lt, rt) < 0) { 2310 /* 2311 * XXX If both operands are constant, make sure 2312 * that there is really a difference between 2313 * ANSI C and traditional C. 2314 */ 2315 if (hflag && allow_trad && allow_c90) 2316 /* semantics of '%s' change in ANSI C; use ... */ 2317 warning(118, op_name(op)); 2318 } 2319 } 2320 2321 static void 2322 typeok_shift(const type_t *ltp, tspec_t lt, const tnode_t *rn, tspec_t rt) 2323 { 2324 if (rn->tn_op != CON) 2325 return; 2326 2327 if (!is_uinteger(rt) && rn->tn_val.u.integer < 0) { 2328 /* negative shift */ 2329 warning(121); 2330 } else if ((uint64_t)rn->tn_val.u.integer == size_in_bits(lt)) { 2331 /* shift amount %u equals bit-size of '%s' */ 2332 warning(267, (unsigned)rn->tn_val.u.integer, type_name(ltp)); 2333 } else if ((uint64_t)rn->tn_val.u.integer > size_in_bits(lt)) { 2334 /* shift amount %llu is greater than bit-size %llu of '%s' */ 2335 warning(122, (unsigned long long)rn->tn_val.u.integer, 2336 (unsigned long long)size_in_bits(lt), 2337 tspec_name(lt)); 2338 } 2339 } 2340 2341 static bool 2342 is_typeok_eq(const tnode_t *ln, tspec_t lt, const tnode_t *rn, tspec_t rt) 2343 { 2344 if (lt == PTR && is_null_pointer(rn)) 2345 return true; 2346 if (rt == PTR && is_null_pointer(ln)) 2347 return true; 2348 return false; 2349 } 2350 2351 /* 2352 * Called if incompatible pointer types are detected. 2353 * Print an appropriate warning. 2354 */ 2355 static void 2356 warn_incompatible_pointers(op_t op, const type_t *ltp, const type_t *rtp) 2357 { 2358 lint_assert(ltp->t_tspec == PTR); 2359 lint_assert(rtp->t_tspec == PTR); 2360 2361 tspec_t lt = ltp->t_subt->t_tspec; 2362 tspec_t rt = rtp->t_subt->t_tspec; 2363 2364 if (is_struct_or_union(lt) && is_struct_or_union(rt)) { 2365 if (op == RETURN) { 2366 /* illegal structure pointer combination */ 2367 warning(244); 2368 } else { 2369 /* incompatible structure pointers: '%s' '%s' '%s' */ 2370 warning(245, type_name(ltp), 2371 op_name(op), type_name(rtp)); 2372 } 2373 } else { 2374 if (op == RETURN) { 2375 /* illegal combination of '%s' and '%s' */ 2376 warning(184, type_name(ltp), type_name(rtp)); 2377 } else { 2378 /* illegal combination of '%s' and '%s', op '%s' */ 2379 warning(124, 2380 type_name(ltp), type_name(rtp), op_name(op)); 2381 } 2382 } 2383 } 2384 2385 static void 2386 check_pointer_comparison(op_t op, const tnode_t *ln, const tnode_t *rn) 2387 { 2388 type_t *ltp = ln->tn_type, *rtp = rn->tn_type; 2389 tspec_t lst = ltp->t_subt->t_tspec, rst = rtp->t_subt->t_tspec; 2390 2391 if (lst == VOID || rst == VOID) { 2392 /* TODO: C99 behaves like C90 here. */ 2393 if ((!allow_trad && !allow_c99) && 2394 (lst == FUNC || rst == FUNC)) { 2395 /* (void *)0 is already handled in typeok() */ 2396 const char *lsts, *rsts; 2397 *(lst == FUNC ? &lsts : &rsts) = "function pointer"; 2398 *(lst == VOID ? &lsts : &rsts) = "'void *'"; 2399 /* ANSI C forbids comparison of %s with %s */ 2400 warning(274, lsts, rsts); 2401 } 2402 return; 2403 } 2404 2405 if (!types_compatible(ltp->t_subt, rtp->t_subt, true, false, NULL)) { 2406 warn_incompatible_pointers(op, ltp, rtp); 2407 return; 2408 } 2409 2410 if (lst == FUNC && rst == FUNC) { 2411 /* TODO: C99 behaves like C90 here, see C99 6.5.8p2. */ 2412 if ((!allow_trad && !allow_c99) && op != EQ && op != NE) 2413 /* ANSI C forbids ordered comparisons of ... */ 2414 warning(125); 2415 } 2416 } 2417 2418 static bool 2419 typeok_compare(op_t op, 2420 const tnode_t *ln, const type_t *ltp, tspec_t lt, 2421 const tnode_t *rn, const type_t *rtp, tspec_t rt) 2422 { 2423 if (lt == PTR && rt == PTR) { 2424 check_pointer_comparison(op, ln, rn); 2425 return true; 2426 } 2427 2428 if (lt != PTR && rt != PTR) 2429 return true; 2430 2431 if (!is_integer(lt) && !is_integer(rt)) { 2432 warn_incompatible_types(op, ltp, lt, rtp, rt); 2433 return false; 2434 } 2435 2436 const char *lx = lt == PTR ? "pointer" : "integer"; 2437 const char *rx = rt == PTR ? "pointer" : "integer"; 2438 /* illegal combination of %s '%s' and %s '%s', op '%s' */ 2439 warning(123, lx, type_name(ltp), rx, type_name(rtp), op_name(op)); 2440 return true; 2441 } 2442 2443 static bool 2444 typeok_quest(tspec_t lt, const tnode_t *rn) 2445 { 2446 if (!is_scalar(lt)) { 2447 /* first operand of '?' must have scalar type */ 2448 error(170); 2449 return false; 2450 } 2451 lint_assert(before_conversion(rn)->tn_op == COLON); 2452 return true; 2453 } 2454 2455 static void 2456 typeok_colon_pointer(const type_t *ltp, const type_t *rtp) 2457 { 2458 type_t *lstp = ltp->t_subt; 2459 type_t *rstp = rtp->t_subt; 2460 tspec_t lst = lstp->t_tspec; 2461 tspec_t rst = rstp->t_tspec; 2462 2463 if ((lst == VOID && rst == FUNC) || (lst == FUNC && rst == VOID)) { 2464 /* (void *)0 is handled in typeok_colon */ 2465 /* TODO: C99 behaves like C90 here. */ 2466 if (!allow_trad && !allow_c99) 2467 /* ANSI C forbids conversion of %s to %s, op %s */ 2468 warning(305, "function pointer", "'void *'", 2469 op_name(COLON)); 2470 return; 2471 } 2472 2473 if (pointer_types_are_compatible(lstp, rstp, true)) 2474 return; 2475 if (!types_compatible(lstp, rstp, true, false, NULL)) 2476 warn_incompatible_pointers(COLON, ltp, rtp); 2477 } 2478 2479 static bool 2480 typeok_colon(const tnode_t *ln, const type_t *ltp, tspec_t lt, 2481 const tnode_t *rn, const type_t *rtp, tspec_t rt) 2482 { 2483 2484 if (is_arithmetic(lt) && is_arithmetic(rt)) 2485 return true; 2486 if (lt == BOOL && rt == BOOL) 2487 return true; 2488 2489 if (lt == STRUCT && rt == STRUCT && ltp->t_sou == rtp->t_sou) 2490 return true; 2491 if (lt == UNION && rt == UNION && ltp->t_sou == rtp->t_sou) 2492 return true; 2493 2494 if (lt == PTR && is_null_pointer(rn)) 2495 return true; 2496 if (rt == PTR && is_null_pointer(ln)) 2497 return true; 2498 2499 if ((lt == PTR && is_integer(rt)) || (is_integer(lt) && rt == PTR)) { 2500 const char *lx = lt == PTR ? "pointer" : "integer"; 2501 const char *rx = rt == PTR ? "pointer" : "integer"; 2502 /* illegal combination of %s '%s' and %s '%s', op '%s' */ 2503 warning(123, lx, type_name(ltp), 2504 rx, type_name(rtp), op_name(COLON)); 2505 return true; 2506 } 2507 2508 if (lt == VOID || rt == VOID) { 2509 if (lt != VOID || rt != VOID) 2510 /* incompatible types '%s' and '%s' in conditional */ 2511 warning(126, type_name(ltp), type_name(rtp)); 2512 return true; 2513 } 2514 2515 if (lt == PTR && rt == PTR) { 2516 typeok_colon_pointer(ltp, rtp); 2517 return true; 2518 } 2519 2520 /* incompatible types '%s' and '%s' in conditional */ 2521 error(126, type_name(ltp), type_name(rtp)); 2522 return false; 2523 } 2524 2525 /* 2526 * Returns true if the given structure or union has a constant member 2527 * (maybe recursively). 2528 */ 2529 static bool 2530 has_constant_member(const type_t *tp) 2531 { 2532 lint_assert(is_struct_or_union(tp->t_tspec)); 2533 2534 for (sym_t *m = tp->t_sou->sou_first_member; 2535 m != NULL; m = m->s_next) { 2536 const type_t *mtp = m->s_type; 2537 if (mtp->t_const) 2538 return true; 2539 if (is_struct_or_union(mtp->t_tspec) && 2540 has_constant_member(mtp)) 2541 return true; 2542 } 2543 return false; 2544 } 2545 2546 static bool 2547 typeok_assign(op_t op, const tnode_t *ln, const type_t *ltp, tspec_t lt) 2548 { 2549 if (op == RETURN || op == INIT || op == FARG) 2550 return true; 2551 2552 if (!ln->tn_lvalue) { 2553 if (ln->tn_op == CVT && ln->tn_cast && 2554 ln->tn_left->tn_op == LOAD) { 2555 /* a cast does not yield an lvalue */ 2556 error(163); 2557 } 2558 /* %soperand of '%s' must be lvalue */ 2559 error(114, "left ", op_name(op)); 2560 return false; 2561 } else if (ltp->t_const 2562 || (is_struct_or_union(lt) && has_constant_member(ltp))) { 2563 if (allow_c90) 2564 /* %soperand of '%s' must be modifiable lvalue */ 2565 warning(115, "left ", op_name(op)); 2566 } 2567 return true; 2568 } 2569 2570 /* Check the types using the information from modtab[]. */ 2571 static bool 2572 typeok_scalar(op_t op, const mod_t *mp, 2573 const type_t *ltp, tspec_t lt, 2574 const type_t *rtp, tspec_t rt) 2575 { 2576 if (mp->m_takes_bool && lt == BOOL && rt == BOOL) 2577 return true; 2578 if (mp->m_requires_integer) { 2579 if (!is_integer(lt) || (mp->m_binary && !is_integer(rt))) { 2580 warn_incompatible_types(op, ltp, lt, rtp, rt); 2581 return false; 2582 } 2583 } else if (mp->m_requires_integer_or_complex) { 2584 if ((!is_integer(lt) && !is_complex(lt)) || 2585 (mp->m_binary && (!is_integer(rt) && !is_complex(rt)))) { 2586 warn_incompatible_types(op, ltp, lt, rtp, rt); 2587 return false; 2588 } 2589 } else if (mp->m_requires_scalar) { 2590 if (!is_scalar(lt) || (mp->m_binary && !is_scalar(rt))) { 2591 warn_incompatible_types(op, ltp, lt, rtp, rt); 2592 return false; 2593 } 2594 } else if (mp->m_requires_arith) { 2595 if (!is_arithmetic(lt) || 2596 (mp->m_binary && !is_arithmetic(rt))) { 2597 warn_incompatible_types(op, ltp, lt, rtp, rt); 2598 return false; 2599 } 2600 } 2601 return true; 2602 } 2603 2604 static void 2605 check_assign_void_pointer(op_t op, int arg, 2606 tspec_t lt, tspec_t lst, 2607 tspec_t rt, tspec_t rst) 2608 { 2609 2610 if (!(lt == PTR && rt == PTR && (lst == VOID || rst == VOID))) 2611 return; 2612 /* two pointers, at least one pointer to void */ 2613 2614 /* TODO: C99 behaves like C90 here. */ 2615 if (!((!allow_trad && !allow_c99) && (lst == FUNC || rst == FUNC))) 2616 return; 2617 /* comb. of ptr to func and ptr to void */ 2618 2619 const char *lts, *rts; 2620 *(lst == FUNC ? <s : &rts) = "function pointer"; 2621 *(lst == VOID ? <s : &rts) = "'void *'"; 2622 2623 switch (op) { 2624 case INIT: 2625 case RETURN: 2626 /* ANSI C forbids conversion of %s to %s */ 2627 warning(303, rts, lts); 2628 break; 2629 case FARG: 2630 /* ANSI C forbids conversion of %s to %s, arg #%d */ 2631 warning(304, rts, lts, arg); 2632 break; 2633 default: 2634 /* ANSI C forbids conversion of %s to %s, op %s */ 2635 warning(305, rts, lts, op_name(op)); 2636 break; 2637 } 2638 } 2639 2640 static bool 2641 is_direct_function_call(const tnode_t *tn, const char **out_name) 2642 { 2643 2644 if (!(tn->tn_op == CALL && 2645 tn->tn_left->tn_op == ADDR && 2646 tn->tn_left->tn_left->tn_op == NAME)) 2647 return false; 2648 2649 *out_name = tn->tn_left->tn_left->tn_sym->s_name; 2650 return true; 2651 } 2652 2653 static bool 2654 is_unconst_function(const char *name) 2655 { 2656 2657 return strcmp(name, "memchr") == 0 || 2658 strcmp(name, "strchr") == 0 || 2659 strcmp(name, "strpbrk") == 0 || 2660 strcmp(name, "strrchr") == 0 || 2661 strcmp(name, "strstr") == 0; 2662 } 2663 2664 static bool 2665 is_const_char_pointer(const tnode_t *tn) 2666 { 2667 /* 2668 * For traditional reasons, C99 6.4.5p5 defines that string literals 2669 * have type 'char[]'. They are often implicitly converted to 2670 * 'char *', for example when they are passed as function arguments. 2671 * 2672 * C99 6.4.5p6 further defines that modifying a string that is 2673 * constructed from a string literal invokes undefined behavior. 2674 * 2675 * Out of these reasons, string literals are treated as 'effectively 2676 * const' here. 2677 */ 2678 if (tn->tn_op == CVT && 2679 tn->tn_left->tn_op == ADDR && 2680 tn->tn_left->tn_left->tn_op == STRING) 2681 return true; 2682 2683 const type_t *tp = before_conversion(tn)->tn_type; 2684 return tp->t_tspec == PTR && 2685 tp->t_subt->t_tspec == CHAR && 2686 tp->t_subt->t_const; 2687 } 2688 2689 static bool 2690 is_first_arg_const_char_pointer(const tnode_t *tn) 2691 { 2692 const tnode_t *an = tn->tn_right; 2693 if (an == NULL) 2694 return false; 2695 2696 while (an->tn_right != NULL) 2697 an = an->tn_right; 2698 return is_const_char_pointer(an->tn_left); 2699 } 2700 2701 static bool 2702 is_const_pointer(const tnode_t *tn) 2703 { 2704 const type_t *tp = before_conversion(tn)->tn_type; 2705 return tp->t_tspec == PTR && tp->t_subt->t_const; 2706 } 2707 2708 static bool 2709 is_second_arg_const_pointer(const tnode_t *tn) 2710 { 2711 const tnode_t *an = tn->tn_right; 2712 if (an == NULL || an->tn_right == NULL) 2713 return false; 2714 2715 while (an->tn_right->tn_right != NULL) 2716 an = an->tn_right; 2717 return is_const_pointer(an->tn_left); 2718 } 2719 2720 static void 2721 check_unconst_function(const type_t *lstp, const tnode_t *rn) 2722 { 2723 const char *function_name; 2724 2725 if (lstp->t_tspec == CHAR && !lstp->t_const && 2726 is_direct_function_call(rn, &function_name) && 2727 is_unconst_function(function_name) && 2728 is_first_arg_const_char_pointer(rn)) { 2729 /* call to '%s' effectively discards 'const' from argument */ 2730 warning(346, function_name); 2731 } 2732 2733 if (!lstp->t_const && 2734 is_direct_function_call(rn, &function_name) && 2735 strcmp(function_name, "bsearch") == 0 && 2736 is_second_arg_const_pointer(rn)) { 2737 /* call to '%s' effectively discards 'const' from argument */ 2738 warning(346, function_name); 2739 } 2740 } 2741 2742 static bool 2743 check_assign_void_pointer_compat(op_t op, int arg, 2744 const type_t *const ltp, tspec_t const lt, 2745 const type_t *const lstp, tspec_t const lst, 2746 const tnode_t *const rn, 2747 const type_t *const rtp, tspec_t const rt, 2748 const type_t *const rstp, tspec_t const rst) 2749 { 2750 if (!(lt == PTR && rt == PTR && (lst == VOID || rst == VOID || 2751 types_compatible(lstp, rstp, 2752 true, false, NULL)))) 2753 return false; 2754 2755 /* compatible pointer types (qualifiers ignored) */ 2756 if (allow_c90 && 2757 ((!lstp->t_const && rstp->t_const) || 2758 (!lstp->t_volatile && rstp->t_volatile))) { 2759 /* left side has not all qualifiers of right */ 2760 switch (op) { 2761 case INIT: 2762 case RETURN: 2763 /* incompatible pointer types to '%s' and '%s' */ 2764 warning(182, type_name(lstp), type_name(rstp)); 2765 break; 2766 case FARG: 2767 /* converting '%s' to incompatible '%s' ... */ 2768 warning(153, 2769 type_name(rtp), type_name(ltp), arg); 2770 break; 2771 default: 2772 /* operands of '%s' have incompatible pointer ... */ 2773 warning(128, op_name(op), 2774 type_name(lstp), type_name(rstp)); 2775 break; 2776 } 2777 } 2778 2779 if (allow_c90) 2780 check_unconst_function(lstp, rn); 2781 2782 return true; 2783 } 2784 2785 static bool 2786 check_assign_pointer_integer(op_t op, int arg, 2787 const type_t *const ltp, tspec_t const lt, 2788 const type_t *const rtp, tspec_t const rt) 2789 { 2790 2791 if (!((lt == PTR && is_integer(rt)) || (is_integer(lt) && rt == PTR))) 2792 return false; 2793 2794 const char *lx = lt == PTR ? "pointer" : "integer"; 2795 const char *rx = rt == PTR ? "pointer" : "integer"; 2796 2797 switch (op) { 2798 case INIT: 2799 case RETURN: 2800 /* illegal combination of %s '%s' and %s '%s' */ 2801 warning(183, lx, type_name(ltp), rx, type_name(rtp)); 2802 break; 2803 case FARG: 2804 /* illegal combination of %s '%s' and %s '%s', arg #%d */ 2805 warning(154, 2806 lx, type_name(ltp), rx, type_name(rtp), arg); 2807 break; 2808 default: 2809 /* illegal combination of %s '%s' and %s '%s', op '%s' */ 2810 warning(123, 2811 lx, type_name(ltp), rx, type_name(rtp), op_name(op)); 2812 break; 2813 } 2814 return true; 2815 } 2816 2817 static bool 2818 check_assign_pointer(op_t op, int arg, 2819 const type_t *ltp, tspec_t lt, 2820 const type_t *rtp, tspec_t rt) 2821 { 2822 if (!(lt == PTR && rt == PTR)) 2823 return false; 2824 2825 if (op == FARG) 2826 /* converting '%s' to incompatible '%s' for ... */ 2827 warning(153, type_name(rtp), type_name(ltp), arg); 2828 else 2829 warn_incompatible_pointers(op, ltp, rtp); 2830 return true; 2831 } 2832 2833 static void 2834 warn_assign(op_t op, int arg, 2835 const type_t *ltp, tspec_t lt, 2836 const type_t *rtp, tspec_t rt) 2837 { 2838 switch (op) { 2839 case INIT: 2840 /* cannot initialize '%s' from '%s' */ 2841 error(185, type_name(ltp), type_name(rtp)); 2842 break; 2843 case RETURN: 2844 /* function has return type '%s' but returns '%s' */ 2845 error(211, type_name(ltp), type_name(rtp)); 2846 break; 2847 case FARG: 2848 /* passing '%s' to incompatible '%s', arg #%d */ 2849 warning(155, type_name(rtp), type_name(ltp), arg); 2850 break; 2851 default: 2852 warn_incompatible_types(op, ltp, lt, rtp, rt); 2853 break; 2854 } 2855 } 2856 2857 /* 2858 * Checks type compatibility for ASSIGN, INIT, FARG and RETURN 2859 * and prints warnings/errors if necessary. 2860 * Returns whether the types are (almost) compatible. 2861 */ 2862 static bool 2863 check_assign_types_compatible(op_t op, int arg, 2864 const tnode_t *ln, const tnode_t *rn) 2865 { 2866 tspec_t lt, rt, lst = NO_TSPEC, rst = NO_TSPEC; 2867 type_t *ltp, *rtp, *lstp = NULL, *rstp = NULL; 2868 2869 if ((lt = (ltp = ln->tn_type)->t_tspec) == PTR) 2870 lst = (lstp = ltp->t_subt)->t_tspec; 2871 if ((rt = (rtp = rn->tn_type)->t_tspec) == PTR) 2872 rst = (rstp = rtp->t_subt)->t_tspec; 2873 2874 if (lt == BOOL && is_scalar(rt)) /* C99 6.3.1.2 */ 2875 return true; 2876 2877 if (is_arithmetic(lt) && (is_arithmetic(rt) || rt == BOOL)) 2878 return true; 2879 2880 if (is_struct_or_union(lt) && is_struct_or_union(rt)) 2881 /* both are struct or union */ 2882 return ltp->t_sou == rtp->t_sou; 2883 2884 /* a null pointer may be assigned to any pointer */ 2885 if (lt == PTR && is_null_pointer(rn)) { 2886 if (is_integer(rn->tn_type->t_tspec)) 2887 /* implicit conversion from integer 0 to pointer ... */ 2888 query_message(15, type_name(ltp)); 2889 return true; 2890 } 2891 2892 check_assign_void_pointer(op, arg, lt, lst, rt, rst); 2893 2894 if (check_assign_void_pointer_compat(op, arg, 2895 ltp, lt, lstp, lst, rn, rtp, rt, rstp, rst)) 2896 return true; 2897 2898 if (check_assign_pointer_integer(op, arg, ltp, lt, rtp, rt)) 2899 return true; 2900 2901 if (check_assign_pointer(op, arg, ltp, lt, rtp, rt)) 2902 return true; 2903 2904 warn_assign(op, arg, ltp, lt, rtp, rt); 2905 return false; 2906 } 2907 2908 static bool 2909 has_side_effect(const tnode_t *tn) /* NOLINT(misc-no-recursion) */ 2910 { 2911 op_t op = tn->tn_op; 2912 2913 if (modtab[op].m_has_side_effect) 2914 return true; 2915 2916 if (op == CVT && tn->tn_type->t_tspec == VOID) 2917 return has_side_effect(tn->tn_left); 2918 2919 /* XXX: Why not has_side_effect(tn->tn_left) as well? */ 2920 if (op == LOGAND || op == LOGOR) 2921 return has_side_effect(tn->tn_right); 2922 2923 /* XXX: Why not has_side_effect(tn->tn_left) as well? */ 2924 if (op == QUEST) 2925 return has_side_effect(tn->tn_right); 2926 2927 if (op == COLON || op == COMMA) { 2928 return has_side_effect(tn->tn_left) || 2929 has_side_effect(tn->tn_right); 2930 } 2931 2932 return false; 2933 } 2934 2935 static bool 2936 is_void_cast(const tnode_t *tn) 2937 { 2938 2939 return tn->tn_op == CVT && tn->tn_cast && 2940 tn->tn_type->t_tspec == VOID; 2941 } 2942 2943 static bool 2944 is_local_symbol(const tnode_t *tn) 2945 { 2946 2947 return tn->tn_op == LOAD && 2948 tn->tn_left->tn_op == NAME && 2949 tn->tn_left->tn_sym->s_scl == AUTO; 2950 } 2951 2952 static bool 2953 is_int_constant_zero(const tnode_t *tn) 2954 { 2955 2956 return tn->tn_op == CON && 2957 tn->tn_type->t_tspec == INT && 2958 tn->tn_val.u.integer == 0; 2959 } 2960 2961 static void 2962 check_null_effect(const tnode_t *tn) 2963 { 2964 2965 if (hflag && 2966 !has_side_effect(tn) && 2967 !(is_void_cast(tn) && is_local_symbol(tn->tn_left)) && 2968 !(is_void_cast(tn) && is_int_constant_zero(tn->tn_left))) { 2969 /* expression has null effect */ 2970 warning(129); 2971 } 2972 } 2973 2974 /* 2975 * Check the types for specific operators and type combinations. 2976 * 2977 * At this point, the operands already conform to the type requirements of 2978 * the operator, such as being integer, floating or scalar. 2979 */ 2980 static bool 2981 typeok_op(op_t op, int arg, 2982 const tnode_t *ln, const type_t *ltp, tspec_t lt, 2983 const tnode_t *rn, const type_t *rtp, tspec_t rt) 2984 { 2985 switch (op) { 2986 case ARROW: 2987 return typeok_arrow(lt); 2988 case POINT: 2989 return typeok_point(ln, ltp, lt); 2990 case INCBEF: 2991 case DECBEF: 2992 case INCAFT: 2993 case DECAFT: 2994 return typeok_incdec(op, ln, ltp); 2995 case INDIR: 2996 return typeok_indir(ltp, lt); 2997 case ADDR: 2998 return typeok_address(op, ln, ltp, lt); 2999 case PLUS: 3000 return typeok_plus(op, ltp, lt, rtp, rt); 3001 case MINUS: 3002 return typeok_minus(op, ltp, lt, rtp, rt); 3003 case SHL: 3004 typeok_shl(op, lt, rt); 3005 goto shift; 3006 case SHR: 3007 typeok_shr(op, ln, lt, rn, rt); 3008 shift: 3009 typeok_shift(ltp, lt, rn, rt); 3010 break; 3011 case LT: 3012 case LE: 3013 case GT: 3014 case GE: 3015 compare: 3016 return typeok_compare(op, ln, ltp, lt, rn, rtp, rt); 3017 case EQ: 3018 case NE: 3019 if (is_typeok_eq(ln, lt, rn, rt)) 3020 break; 3021 goto compare; 3022 case QUEST: 3023 return typeok_quest(lt, rn); 3024 case COLON: 3025 return typeok_colon(ln, ltp, lt, rn, rtp, rt); 3026 case ASSIGN: 3027 case INIT: 3028 case FARG: 3029 case RETURN: 3030 if (!check_assign_types_compatible(op, arg, ln, rn)) 3031 return false; 3032 goto assign; 3033 case MULASS: 3034 case DIVASS: 3035 case MODASS: 3036 goto assign; 3037 case ADDASS: 3038 case SUBASS: 3039 if ((lt == PTR && !is_integer(rt)) || rt == PTR) { 3040 warn_incompatible_types(op, ltp, lt, rtp, rt); 3041 return false; 3042 } 3043 goto assign; 3044 case SHLASS: 3045 goto assign; 3046 case SHRASS: 3047 if (pflag && !is_uinteger(lt) && 3048 !(!allow_c90 && is_uinteger(rt))) { 3049 /* bitwise '%s' on signed value possibly nonportable */ 3050 warning(117, op_name(op)); 3051 } 3052 goto assign; 3053 case ANDASS: 3054 case XORASS: 3055 case ORASS: 3056 assign: 3057 return typeok_assign(op, ln, ltp, lt); 3058 case COMMA: 3059 if (!modtab[ln->tn_op].m_has_side_effect) 3060 check_null_effect(ln); 3061 break; 3062 default: 3063 break; 3064 } 3065 return true; 3066 } 3067 3068 /* Prints a warning if a strange operator is used on an enum type. */ 3069 static void 3070 check_bad_enum_operation(op_t op, const tnode_t *ln, const tnode_t *rn) 3071 { 3072 3073 if (!eflag) 3074 return; 3075 3076 /* Allow enum in array indices. */ 3077 if (op == PLUS && 3078 ((ln->tn_type->t_is_enum && rn->tn_type->t_tspec == PTR) || 3079 (rn->tn_type->t_is_enum && ln->tn_type->t_tspec == PTR))) { 3080 return; 3081 } 3082 3083 /* dubious operation '%s' on enum */ 3084 warning(241, op_name(op)); 3085 } 3086 3087 /* Prints a warning if an operator is applied to two different enum types. */ 3088 static void 3089 check_enum_type_mismatch(op_t op, int arg, const tnode_t *ln, const tnode_t *rn) 3090 { 3091 const mod_t *mp = &modtab[op]; 3092 3093 if (ln->tn_type->t_enum != rn->tn_type->t_enum) { 3094 switch (op) { 3095 case INIT: 3096 /* enum type mismatch between '%s' and '%s' in ... */ 3097 warning(210, 3098 type_name(ln->tn_type), type_name(rn->tn_type)); 3099 break; 3100 case FARG: 3101 /* function expects '%s', passing '%s' for arg #%d */ 3102 warning(156, 3103 type_name(ln->tn_type), type_name(rn->tn_type), 3104 arg); 3105 break; 3106 case RETURN: 3107 /* function has return type '%s' but returns '%s' */ 3108 warning(211, 3109 type_name(ln->tn_type), type_name(rn->tn_type)); 3110 break; 3111 default: 3112 /* enum type mismatch: '%s' '%s' '%s' */ 3113 warning(130, type_name(ln->tn_type), op_name(op), 3114 type_name(rn->tn_type)); 3115 break; 3116 } 3117 } else if (Pflag && eflag && mp->m_comparison && op != EQ && op != NE) 3118 /* operator '%s' assumes that '%s' is ordered */ 3119 warning(243, op_name(op), type_name(ln->tn_type)); 3120 } 3121 3122 /* Prints a warning if the operands mix between enum and integer. */ 3123 static void 3124 check_enum_int_mismatch(op_t op, int arg, const tnode_t *ln, const tnode_t *rn) 3125 { 3126 3127 if (!eflag) 3128 return; 3129 3130 switch (op) { 3131 case INIT: 3132 /* 3133 * Initialization with 0 is allowed. Otherwise, all implicit 3134 * initializations would need to be warned upon as well. 3135 */ 3136 if (!rn->tn_type->t_is_enum && rn->tn_op == CON && 3137 is_integer(rn->tn_type->t_tspec) && 3138 rn->tn_val.u.integer == 0) { 3139 return; 3140 } 3141 /* initialization of '%s' with '%s' */ 3142 warning(277, type_name(ln->tn_type), type_name(rn->tn_type)); 3143 break; 3144 case FARG: 3145 /* combination of '%s' and '%s', arg #%d */ 3146 warning(278, 3147 type_name(ln->tn_type), type_name(rn->tn_type), arg); 3148 break; 3149 case RETURN: 3150 /* combination of '%s' and '%s' in return */ 3151 warning(279, type_name(ln->tn_type), type_name(rn->tn_type)); 3152 break; 3153 default: 3154 /* combination of '%s' and '%s', op '%s' */ 3155 warning(242, type_name(ln->tn_type), type_name(rn->tn_type), 3156 op_name(op)); 3157 break; 3158 } 3159 } 3160 3161 static void 3162 typeok_enum(op_t op, const mod_t *mp, int arg, 3163 const tnode_t *ln, const type_t *ltp, 3164 const tnode_t *rn, const type_t *rtp) 3165 { 3166 if (mp->m_bad_on_enum && 3167 (ltp->t_is_enum || (mp->m_binary && rtp->t_is_enum))) { 3168 check_bad_enum_operation(op, ln, rn); 3169 } else if (mp->m_valid_on_enum && 3170 (ltp->t_is_enum && rtp != NULL && rtp->t_is_enum)) { 3171 check_enum_type_mismatch(op, arg, ln, rn); 3172 } else if (mp->m_valid_on_enum && 3173 (ltp->t_is_enum || (rtp != NULL && rtp->t_is_enum))) { 3174 check_enum_int_mismatch(op, arg, ln, rn); 3175 } 3176 } 3177 3178 /* Perform most type checks. Return whether the types are ok. */ 3179 bool 3180 typeok(op_t op, int arg, const tnode_t *ln, const tnode_t *rn) 3181 { 3182 3183 const mod_t *mp = &modtab[op]; 3184 3185 type_t *ltp = ln->tn_type; 3186 tspec_t lt = ltp->t_tspec; 3187 3188 type_t *rtp = mp->m_binary ? rn->tn_type : NULL; 3189 tspec_t rt = mp->m_binary ? rtp->t_tspec : NO_TSPEC; 3190 3191 if (Tflag && !typeok_scalar_strict_bool(op, mp, arg, ln, rn)) 3192 return false; 3193 if (!typeok_scalar(op, mp, ltp, lt, rtp, rt)) 3194 return false; 3195 3196 if (!typeok_op(op, arg, ln, ltp, lt, rn, rtp, rt)) 3197 return false; 3198 3199 typeok_enum(op, mp, arg, ln, ltp, rn, rtp); 3200 return true; 3201 } 3202 3203 /* In traditional C, keep unsigned and promote FLOAT to DOUBLE. */ 3204 static tspec_t 3205 promote_trad(tspec_t t) 3206 { 3207 3208 if (t == UCHAR || t == USHORT) 3209 return UINT; 3210 if (t == CHAR || t == SCHAR || t == SHORT) 3211 return INT; 3212 if (t == FLOAT) 3213 return DOUBLE; 3214 if (t == ENUM) 3215 return INT; 3216 return t; 3217 } 3218 3219 /* 3220 * C99 6.3.1.1p2 requires for types with lower rank than int that "If an int 3221 * can represent all the values of the original type, the value is converted 3222 * to an int; otherwise it is converted to an unsigned int", and that "All 3223 * other types are unchanged by the integer promotions". 3224 */ 3225 static tspec_t 3226 promote_c90(const tnode_t *tn, tspec_t t, bool farg) 3227 { 3228 if (tn->tn_type->t_bitfield) { 3229 unsigned int width = tn->tn_type->t_bit_field_width; 3230 unsigned int int_width = size_in_bits(INT); 3231 // XXX: What about _Bool bit-fields, since C99? 3232 if (width < int_width) 3233 return INT; 3234 if (width == int_width) 3235 return is_uinteger(t) ? UINT : INT; 3236 return t; 3237 } 3238 3239 if (t == CHAR || t == SCHAR) 3240 return INT; 3241 if (t == UCHAR) 3242 return size_in_bits(CHAR) < size_in_bits(INT) ? INT : UINT; 3243 if (t == SHORT) 3244 return INT; 3245 if (t == USHORT) 3246 return size_in_bits(SHORT) < size_in_bits(INT) ? INT : UINT; 3247 if (t == ENUM) 3248 return INT; 3249 if (farg && t == FLOAT) 3250 return DOUBLE; 3251 return t; 3252 } 3253 3254 /* 3255 * Performs the "integer promotions" (C99 6.3.1.1p2), which convert small 3256 * integer types to either int or unsigned int. 3257 * 3258 * If allow_c90 is unset or the operand is a function argument with no type 3259 * information (no prototype or variable # of args), converts float to double. 3260 */ 3261 tnode_t * 3262 promote(op_t op, bool farg, tnode_t *tn) 3263 { 3264 3265 tspec_t ot = tn->tn_type->t_tspec; 3266 if (!is_arithmetic(ot)) 3267 return tn; 3268 3269 tspec_t nt = allow_c90 ? promote_c90(tn, ot, farg) : promote_trad(ot); 3270 if (nt == ot) 3271 return tn; 3272 3273 type_t *ntp = expr_dup_type(tn->tn_type); 3274 ntp->t_tspec = nt; 3275 /* 3276 * Keep t_is_enum even though t_tspec gets converted from 3277 * ENUM to INT, so we are later able to check compatibility 3278 * of enum types. 3279 */ 3280 return convert(op, 0, ntp, tn); 3281 } 3282 3283 static void 3284 convert_integer_from_floating(op_t op, const type_t *tp, const tnode_t *tn) 3285 { 3286 3287 if (op == CVT) 3288 /* cast from floating point '%s' to integer '%s' */ 3289 query_message(2, type_name(tn->tn_type), type_name(tp)); 3290 else 3291 /* implicit conversion from floating point '%s' to ... */ 3292 query_message(1, type_name(tn->tn_type), type_name(tp)); 3293 } 3294 3295 static bool 3296 should_warn_about_prototype_conversion(tspec_t nt, 3297 tspec_t ot, const tnode_t *ptn) 3298 { 3299 3300 if (nt == ot) 3301 return false; 3302 3303 if (nt == ENUM && ot == INT) 3304 return false; 3305 3306 if (is_floating(nt) != is_floating(ot) || 3307 portable_rank_cmp(nt, ot) != 0) { 3308 /* representation and/or width change */ 3309 if (!is_integer(ot)) 3310 return true; 3311 /* 3312 * XXX: Investigate whether this rule makes sense; see 3313 * tests/usr.bin/xlint/lint1/platform_long.c. 3314 */ 3315 return portable_rank_cmp(ot, INT) > 0; 3316 } 3317 3318 if (!hflag) 3319 return false; 3320 3321 /* 3322 * If the types differ only in sign and the argument has the same 3323 * representation in both types, print no warning. 3324 */ 3325 if (ptn->tn_op == CON && is_integer(nt) && 3326 signed_type(nt) == signed_type(ot) && 3327 !msb(ptn->tn_val.u.integer, ot)) 3328 return false; 3329 3330 return true; 3331 } 3332 3333 /* 3334 * Warn if a prototype causes a type conversion that is different from what 3335 * would happen to the same argument in the absence of a prototype. This 3336 * check is intended for code that needs to stay compatible with pre-C90 C. 3337 * 3338 * Errors/warnings about illegal type combinations are already printed 3339 * in check_assign_types_compatible(). 3340 */ 3341 static void 3342 check_prototype_conversion(int arg, tspec_t nt, tspec_t ot, type_t *tp, 3343 tnode_t *tn) 3344 { 3345 3346 if (!is_arithmetic(nt) || !is_arithmetic(ot)) 3347 return; 3348 3349 /* 3350 * If the type of the formal parameter is char/short, a warning 3351 * would be useless, because functions declared the old style 3352 * can't expect char/short arguments. 3353 */ 3354 if (nt == CHAR || nt == SCHAR || nt == UCHAR || 3355 nt == SHORT || nt == USHORT) 3356 return; 3357 3358 /* apply the default promotion */ 3359 tnode_t *ptn = promote(NOOP, true, tn); 3360 ot = ptn->tn_type->t_tspec; 3361 3362 if (should_warn_about_prototype_conversion(nt, ot, ptn)) { 3363 /* argument %d is converted from '%s' to '%s' ... */ 3364 warning(259, arg, type_name(tn->tn_type), type_name(tp)); 3365 } 3366 } 3367 3368 /* 3369 * When converting a large integer type to a small integer type, in some 3370 * cases the value of the actual expression is further restricted than the 3371 * type bounds, such as in (expr & 0xFF) or (expr % 100) or (expr >> 24). 3372 */ 3373 static bool 3374 can_represent(const type_t *tp, const tnode_t *tn) 3375 { 3376 3377 debug_step("%s: type '%s'", __func__, type_name(tp)); 3378 debug_node(tn); 3379 3380 uint64_t nmask = value_bits(width_in_bits(tp)); 3381 if (!is_uinteger(tp->t_tspec)) 3382 nmask >>= 1; 3383 3384 integer_constraints c = ic_expr(tn); 3385 if ((~c.bclr & ~nmask) == 0) 3386 return true; 3387 3388 integer_constraints tpc = ic_any(tp); 3389 if (is_uinteger(tp->t_tspec) 3390 ? tpc.umin <= c.umin && tpc.umax >= c.umax 3391 : tpc.smin <= c.smin && tpc.smax >= c.smax) 3392 return true; 3393 3394 return false; 3395 } 3396 3397 static void 3398 convert_integer_from_integer(op_t op, int arg, tspec_t nt, tspec_t ot, 3399 type_t *tp, tnode_t *tn) 3400 { 3401 3402 if (tn->tn_op == CON) 3403 return; 3404 3405 if (op == CVT) 3406 return; 3407 3408 if (Pflag && pflag && aflag > 0 && 3409 portable_rank_cmp(nt, ot) > 0 && 3410 is_uinteger(nt) != is_uinteger(ot)) { 3411 if (op == FARG) { 3412 /* conversion to '%s' may sign-extend ... */ 3413 warning(297, type_name(tp), arg); 3414 } else { 3415 /* conversion to '%s' may sign-extend ... */ 3416 warning(131, type_name(tp)); 3417 } 3418 } 3419 3420 if (Pflag && portable_rank_cmp(nt, ot) > 0 && 3421 (tn->tn_op == PLUS || tn->tn_op == MINUS || tn->tn_op == MULT || 3422 tn->tn_op == SHL)) { 3423 /* suggest cast from '%s' to '%s' on op '%s' to ... */ 3424 warning(324, type_name(gettyp(ot)), type_name(tp), 3425 op_name(tn->tn_op)); 3426 } 3427 3428 if (aflag > 0 && 3429 portable_rank_cmp(nt, ot) < 0 && 3430 (portable_rank_cmp(ot, LONG) >= 0 || aflag > 1) && 3431 // XXX: The portable_rank_cmp above aims at portable mode, 3432 // independent of the current platform, while can_represent acts 3433 // on the actual type sizes from the current platform. This mix 3434 // is inconsistent, but anything else would make the exact 3435 // conditions too complicated to grasp. 3436 !can_represent(tp, tn)) { 3437 if (op == FARG) { 3438 /* conversion from '%s' to '%s' may lose ... */ 3439 warning(298, 3440 type_name(tn->tn_type), type_name(tp), arg); 3441 } else { 3442 /* conversion from '%s' to '%s' may lose accuracy */ 3443 warning(132, 3444 type_name(tn->tn_type), type_name(tp)); 3445 } 3446 } 3447 3448 if (any_query_enabled && is_uinteger(nt) != is_uinteger(ot)) 3449 /* implicit conversion changes sign from '%s' to '%s' */ 3450 query_message(3, type_name(tn->tn_type), type_name(tp)); 3451 } 3452 3453 static void 3454 convert_integer_from_pointer(op_t op, tspec_t nt, type_t *tp, tnode_t *tn) 3455 { 3456 3457 if (tn->tn_op == CON) 3458 return; 3459 if (op != CVT) 3460 return; /* We already got an error. */ 3461 if (portable_rank_cmp(nt, PTR) >= 0) 3462 return; 3463 3464 if (pflag && size_in_bits(nt) >= size_in_bits(PTR)) { 3465 /* conversion of pointer to '%s' may lose bits */ 3466 warning(134, type_name(tp)); 3467 } else { 3468 /* conversion of pointer to '%s' loses bits */ 3469 warning(133, type_name(tp)); 3470 } 3471 } 3472 3473 static bool 3474 struct_starts_with(const type_t *struct_tp, const type_t *member_tp) 3475 { 3476 3477 return struct_tp->t_sou->sou_first_member != NULL && 3478 types_compatible(struct_tp->t_sou->sou_first_member->s_type, 3479 member_tp, true, false, NULL); 3480 } 3481 3482 static bool 3483 is_byte_array(const type_t *tp) 3484 { 3485 3486 return tp->t_tspec == ARRAY && 3487 (tp->t_subt->t_tspec == CHAR || tp->t_subt->t_tspec == UCHAR); 3488 } 3489 3490 static bool 3491 union_contains(const type_t *utp, const type_t *mtp) 3492 { 3493 for (const sym_t *mem = utp->t_sou->sou_first_member; 3494 mem != NULL; mem = mem->s_next) { 3495 if (types_compatible(mem->s_type, mtp, true, false, NULL)) 3496 return true; 3497 } 3498 return false; 3499 } 3500 3501 static bool 3502 should_warn_about_pointer_cast(const type_t *nstp, tspec_t nst, 3503 const type_t *ostp, tspec_t ost) 3504 { 3505 3506 while (nst == ARRAY) 3507 nstp = nstp->t_subt, nst = nstp->t_tspec; 3508 while (ost == ARRAY) 3509 ostp = ostp->t_subt, ost = ostp->t_tspec; 3510 3511 if (nst == STRUCT && ost == STRUCT && 3512 (struct_starts_with(nstp, ostp) || 3513 struct_starts_with(ostp, nstp))) 3514 return false; 3515 3516 if (is_incomplete(nstp) || is_incomplete(ostp)) 3517 return false; 3518 3519 if (nst == CHAR || nst == UCHAR) 3520 return false; /* for the sake of traditional C code */ 3521 if (ost == CHAR || ost == UCHAR) 3522 return false; /* for the sake of traditional C code */ 3523 3524 /* Allow cast between pointers to sockaddr variants. */ 3525 if (nst == STRUCT && ost == STRUCT) { 3526 const sym_t *nmem = nstp->t_sou->sou_first_member; 3527 const sym_t *omem = ostp->t_sou->sou_first_member; 3528 while (nmem != NULL && omem != NULL && 3529 types_compatible(nmem->s_type, omem->s_type, 3530 true, false, NULL)) 3531 nmem = nmem->s_next, omem = omem->s_next; 3532 if (nmem != NULL && is_byte_array(nmem->s_type)) 3533 return false; 3534 if (omem != NULL && is_byte_array(omem->s_type)) 3535 return false; 3536 if (nmem == NULL && omem == NULL) 3537 return false; 3538 } 3539 3540 if (nst == UNION || ost == UNION) { 3541 const type_t *union_tp = nst == UNION ? nstp : ostp; 3542 const type_t *other_tp = nst == UNION ? ostp : nstp; 3543 if (union_contains(union_tp, other_tp)) 3544 return false; 3545 } 3546 3547 if (is_struct_or_union(nst) && is_struct_or_union(ost)) 3548 return nstp->t_sou != ostp->t_sou; 3549 3550 enum rank_kind rk1 = type_properties(nst)->tt_rank_kind; 3551 enum rank_kind rk2 = type_properties(ost)->tt_rank_kind; 3552 if (rk1 != rk2 || rk1 == RK_NONE) 3553 return true; 3554 3555 return portable_rank_cmp(nst, ost) != 0; 3556 } 3557 3558 static void 3559 convert_pointer_from_pointer(type_t *ntp, tnode_t *tn) 3560 { 3561 const type_t *nstp = ntp->t_subt; 3562 const type_t *otp = tn->tn_type; 3563 const type_t *ostp = otp->t_subt; 3564 tspec_t nst = nstp->t_tspec; 3565 tspec_t ost = ostp->t_tspec; 3566 3567 if (nst == VOID || ost == VOID) { 3568 /* TODO: C99 behaves like C90 here. */ 3569 if ((!allow_trad && !allow_c99) && (nst == FUNC || ost == FUNC)) { 3570 const char *nts, *ots; 3571 /* null pointers are already handled in convert() */ 3572 *(nst == FUNC ? &nts : &ots) = "function pointer"; 3573 *(nst == VOID ? &nts : &ots) = "'void *'"; 3574 /* ANSI C forbids conversion of %s to %s */ 3575 warning(303, ots, nts); 3576 } 3577 return; 3578 } 3579 if (nst == FUNC && ost == FUNC) 3580 return; 3581 if (nst == FUNC || ost == FUNC) { 3582 /* converting '%s' to '%s' is questionable */ 3583 warning(229, type_name(otp), type_name(ntp)); 3584 return; 3585 } 3586 3587 if (hflag && alignment_in_bits(nstp) > alignment_in_bits(ostp) && 3588 ost != CHAR && ost != UCHAR && 3589 !is_incomplete(ostp) && 3590 !(nst == UNION && union_contains(nstp, ostp))) { 3591 /* converting '%s' to '%s' increases alignment ... */ 3592 warning(135, type_name(otp), type_name(ntp), 3593 alignment_in_bits(ostp) / CHAR_SIZE, 3594 alignment_in_bits(nstp) / CHAR_SIZE); 3595 } 3596 3597 if (cflag && should_warn_about_pointer_cast(nstp, nst, ostp, ost)) { 3598 /* pointer cast from '%s' to '%s' may be troublesome */ 3599 warning(247, type_name(otp), type_name(ntp)); 3600 } 3601 } 3602 3603 /* 3604 * Insert a conversion operator, which converts the type of the node 3605 * to another given type. 3606 * 3607 * Possible values for 'op': 3608 * CVT a cast-expression 3609 * binary integer promotion for one of the operands, or a usual 3610 * arithmetic conversion 3611 * binary plain or compound assignments to bit-fields 3612 * FARG 'arg' is the number of the argument (used for warnings) 3613 * NOOP several other implicit conversions 3614 * ... 3615 */ 3616 tnode_t * 3617 convert(op_t op, int arg, type_t *tp, tnode_t *tn) 3618 { 3619 tspec_t nt = tp->t_tspec; 3620 tspec_t ot = tn->tn_type->t_tspec; 3621 3622 if (allow_trad && allow_c90 && op == FARG) 3623 check_prototype_conversion(arg, nt, ot, tp, tn); 3624 3625 if (nt == BOOL) { 3626 /* No further checks. */ 3627 3628 } else if (is_integer(nt)) { 3629 if (ot == BOOL) { 3630 /* No further checks. */ 3631 } else if (is_integer(ot)) 3632 convert_integer_from_integer(op, arg, nt, ot, tp, tn); 3633 else if (is_floating(ot)) 3634 convert_integer_from_floating(op, tp, tn); 3635 else if (ot == PTR) 3636 convert_integer_from_pointer(op, nt, tp, tn); 3637 3638 } else if (is_floating(nt)) { 3639 /* No further checks. */ 3640 3641 } else if (nt == PTR) { 3642 if (is_null_pointer(tn)) { 3643 /* a null pointer may be assigned to any pointer. */ 3644 } else if (ot == PTR && op == CVT) 3645 convert_pointer_from_pointer(tp, tn); 3646 } 3647 3648 tnode_t *ntn = expr_alloc_tnode(); 3649 ntn->tn_op = CVT; 3650 ntn->tn_type = tp; 3651 ntn->tn_cast = op == CVT; 3652 ntn->tn_sys |= tn->tn_sys; 3653 ntn->tn_right = NULL; 3654 if (tn->tn_op != CON || nt == VOID) { 3655 ntn->tn_left = tn; 3656 } else { 3657 ntn->tn_op = CON; 3658 convert_constant(op, arg, ntn->tn_type, &ntn->tn_val, 3659 &tn->tn_val); 3660 } 3661 3662 return ntn; 3663 } 3664 3665 static void 3666 convert_constant_floating(op_t op, int arg, tspec_t ot, const type_t *tp, 3667 tspec_t nt, val_t *v, val_t *nv) 3668 { 3669 long double max = 0.0, min = 0.0; 3670 3671 switch (nt) { 3672 case CHAR: 3673 max = TARG_CHAR_MAX; min = TARG_CHAR_MIN; break; 3674 case UCHAR: 3675 max = TARG_UCHAR_MAX; min = 0; break; 3676 case SCHAR: 3677 max = TARG_SCHAR_MAX; min = TARG_SCHAR_MIN; break; 3678 case SHORT: 3679 max = TARG_SHRT_MAX; min = TARG_SHRT_MIN; break; 3680 case USHORT: 3681 max = TARG_USHRT_MAX; min = 0; break; 3682 case ENUM: 3683 case INT: 3684 max = TARG_INT_MAX; min = TARG_INT_MIN; break; 3685 case UINT: 3686 max = TARG_UINT_MAX; min = 0; break; 3687 case LONG: 3688 max = TARG_LONG_MAX; min = TARG_LONG_MIN; break; 3689 case ULONG: 3690 max = TARG_ULONG_MAX; min = 0; break; 3691 case LLONG: 3692 max = LLONG_MAX; min = LLONG_MIN; break; 3693 case ULLONG: 3694 max = ULLONG_MAX; min = 0; break; 3695 case FLOAT: 3696 case FCOMPLEX: 3697 max = FLT_MAX; min = -FLT_MAX; break; 3698 case DOUBLE: 3699 case DCOMPLEX: 3700 max = DBL_MAX; min = -DBL_MAX; break; 3701 case PTR: 3702 /* Already got an error because of float --> ptr */ 3703 case LDOUBLE: 3704 case LCOMPLEX: 3705 /* LINTED 248 */ 3706 max = LDBL_MAX; min = -max; break; 3707 default: 3708 lint_assert(/*CONSTCOND*/false); 3709 } 3710 if (v->u.floating > max || v->u.floating < min) { 3711 lint_assert(nt != LDOUBLE); 3712 if (op == FARG) { 3713 /* conversion of '%s' to '%s' is out of range, ... */ 3714 warning(295, 3715 type_name(gettyp(ot)), type_name(tp), arg); 3716 } else { 3717 /* conversion of '%s' to '%s' is out of range */ 3718 warning(119, type_name(gettyp(ot)), type_name(tp)); 3719 } 3720 v->u.floating = v->u.floating > 0 ? max : min; 3721 } 3722 3723 if (nt == FLOAT || nt == FCOMPLEX) 3724 nv->u.floating = (float)v->u.floating; 3725 else if (nt == DOUBLE || nt == DCOMPLEX) 3726 nv->u.floating = (double)v->u.floating; 3727 else if (nt == LDOUBLE || nt == LCOMPLEX) 3728 nv->u.floating = v->u.floating; 3729 else 3730 nv->u.integer = (int64_t)v->u.floating; 3731 } 3732 3733 static bool 3734 convert_constant_to_floating(tspec_t nt, val_t *nv, 3735 tspec_t ot, const val_t *v) 3736 { 3737 if (nt == FLOAT) { 3738 nv->u.floating = (ot == PTR || is_uinteger(ot)) ? 3739 (float)(uint64_t)v->u.integer : (float)v->u.integer; 3740 } else if (nt == DOUBLE) { 3741 nv->u.floating = (ot == PTR || is_uinteger(ot)) ? 3742 (double)(uint64_t)v->u.integer : (double)v->u.integer; 3743 } else if (nt == LDOUBLE) { 3744 nv->u.floating = (ot == PTR || is_uinteger(ot)) 3745 ? (long double)(uint64_t)v->u.integer 3746 : (long double)v->u.integer; 3747 } else 3748 return false; 3749 return true; 3750 } 3751 3752 /* 3753 * Print a warning if bits which were set are lost due to the conversion. 3754 * This can happen with operator ORASS only. 3755 */ 3756 static void 3757 convert_constant_check_range_bitor(size_t nsz, size_t osz, const val_t *v, 3758 uint64_t xmask, op_t op) 3759 { 3760 if (nsz < osz && (v->u.integer & xmask) != 0) { 3761 /* constant truncated by conversion, op '%s' */ 3762 warning(306, op_name(op)); 3763 } 3764 } 3765 3766 /* 3767 * Print a warning if additional bits are not all 1 3768 * and the most significant bit of the old value is 1, 3769 * or if at least one (but not all) removed bit was 0. 3770 */ 3771 static void 3772 convert_constant_check_range_bitand(size_t nsz, size_t osz, 3773 uint64_t xmask, const val_t *nv, 3774 tspec_t ot, const val_t *v, 3775 const type_t *tp, op_t op) 3776 { 3777 if (nsz > osz && 3778 (nv->u.integer & bit((unsigned int)(osz - 1))) != 0 && 3779 (nv->u.integer & xmask) != xmask) { 3780 /* extra bits set to 0 in conversion of '%s' to '%s', ... */ 3781 warning(309, type_name(gettyp(ot)), 3782 type_name(tp), op_name(op)); 3783 } else if (nsz < osz && 3784 (v->u.integer & xmask) != xmask && 3785 (v->u.integer & xmask) != 0) { 3786 /* constant truncated by conversion, op '%s' */ 3787 warning(306, op_name(op)); 3788 } 3789 } 3790 3791 static void 3792 convert_constant_check_range_signed(op_t op, int arg) 3793 { 3794 if (op == ASSIGN) { 3795 /* assignment of negative constant to unsigned type */ 3796 warning(164); 3797 } else if (op == INIT) { 3798 /* initialization of unsigned with negative constant */ 3799 warning(221); 3800 } else if (op == FARG) { 3801 /* conversion of negative constant to unsigned type, ... */ 3802 warning(296, arg); 3803 } else if (modtab[op].m_comparison) { 3804 /* handled by check_integer_comparison() */ 3805 } else { 3806 /* conversion of negative constant to unsigned type */ 3807 warning(222); 3808 } 3809 } 3810 3811 /* 3812 * Loss of significant bit(s). All truncated bits of unsigned types or all 3813 * truncated bits plus the msb of the target for signed types are considered 3814 * to be significant bits. Loss of significant bits means that at least one 3815 * of the bits was set in an unsigned type or that at least one but not all 3816 * of the bits was set in a signed type. Loss of significant bits means that 3817 * it is not possible, also not with necessary casts, to convert back to the 3818 * original type. An example for a necessary cast is: 3819 * char c; int i; c = 128; 3820 * i = c; ** yields -128 ** 3821 * i = (unsigned char)c; ** yields 128 ** 3822 */ 3823 static void 3824 warn_constant_check_range_truncated(op_t op, int arg, const type_t *tp, 3825 tspec_t ot) 3826 { 3827 if (op == ASSIGN && tp->t_bitfield) 3828 /* precision lost in bit-field assignment */ 3829 warning(166); 3830 else if (op == ASSIGN) 3831 /* constant truncated by assignment */ 3832 warning(165); 3833 else if (op == INIT && tp->t_bitfield) 3834 /* bit-field initializer does not fit */ 3835 warning(180); 3836 else if (op == INIT) 3837 /* initializer does not fit */ 3838 warning(178); 3839 else if (op == CASE) 3840 /* case label affected by conversion */ 3841 warning(196); 3842 else if (op == FARG) 3843 /* conversion of '%s' to '%s' is out of range, arg #%d */ 3844 warning(295, type_name(gettyp(ot)), type_name(tp), arg); 3845 else 3846 /* conversion of '%s' to '%s' is out of range */ 3847 warning(119, type_name(gettyp(ot)), type_name(tp)); 3848 } 3849 3850 static void 3851 warn_constant_check_range_loss(op_t op, int arg, const type_t *tp, 3852 tspec_t ot) 3853 { 3854 if (op == ASSIGN && tp->t_bitfield) 3855 /* precision lost in bit-field assignment */ 3856 warning(166); 3857 else if (op == INIT && tp->t_bitfield) 3858 /* bit-field initializer out of range */ 3859 warning(11); 3860 else if (op == CASE) 3861 /* case label affected by conversion */ 3862 warning(196); 3863 else if (op == FARG) 3864 /* conversion of '%s' to '%s' is out of range, arg #%d */ 3865 warning(295, type_name(gettyp(ot)), type_name(tp), arg); 3866 else 3867 /* conversion of '%s' to '%s' is out of range */ 3868 warning(119, type_name(gettyp(ot)), type_name(tp)); 3869 } 3870 3871 static void 3872 convert_constant_check_range(tspec_t ot, const type_t *tp, tspec_t nt, 3873 op_t op, int arg, const val_t *v, val_t *nv) 3874 { 3875 unsigned int obitsz, nbitsz; 3876 uint64_t xmask, xmsk1; 3877 3878 obitsz = size_in_bits(ot); 3879 nbitsz = tp->t_bitfield ? tp->t_bit_field_width : size_in_bits(nt); 3880 xmask = value_bits(nbitsz) ^ value_bits(obitsz); 3881 xmsk1 = value_bits(nbitsz) ^ value_bits(obitsz - 1); 3882 /* 3883 * For bitwise operations we are not interested in the arithmetic 3884 * value, but in the bits itself. 3885 */ 3886 if (op == ORASS || op == BITOR || op == BITXOR) { 3887 convert_constant_check_range_bitor( 3888 nbitsz, obitsz, v, xmask, op); 3889 } else if (op == ANDASS || op == BITAND) { 3890 convert_constant_check_range_bitand( 3891 nbitsz, obitsz, xmask, nv, ot, v, tp, op); 3892 } else if ((nt != PTR && is_uinteger(nt)) && 3893 (ot != PTR && !is_uinteger(ot)) && 3894 v->u.integer < 0) 3895 convert_constant_check_range_signed(op, arg); 3896 else if (nv->u.integer != v->u.integer && nbitsz <= obitsz && 3897 (v->u.integer & xmask) != 0 && 3898 (is_uinteger(ot) || (v->u.integer & xmsk1) != xmsk1)) 3899 warn_constant_check_range_truncated(op, arg, tp, ot); 3900 else if (nv->u.integer != v->u.integer) 3901 warn_constant_check_range_loss(op, arg, tp, ot); 3902 } 3903 3904 /* 3905 * Converts a typed constant to a constant of another type. 3906 * 3907 * op operator which requires conversion 3908 * arg if op is FARG, # of argument 3909 * tp type to which to convert the constant 3910 * nv new constant 3911 * v old constant 3912 */ 3913 void 3914 convert_constant(op_t op, int arg, const type_t *tp, val_t *nv, val_t *v) 3915 { 3916 /* 3917 * TODO: make 'v' const; the name of this function does not suggest 3918 * that it modifies 'v'. 3919 */ 3920 tspec_t ot = v->v_tspec; 3921 tspec_t nt = nv->v_tspec = tp->t_tspec; 3922 bool range_check = false; 3923 3924 if (nt == BOOL) { /* C99 6.3.1.2 */ 3925 nv->v_unsigned_since_c90 = false; 3926 nv->u.integer = is_nonzero_val(v) ? 1 : 0; 3927 return; 3928 } 3929 3930 if (ot == FLOAT || ot == DOUBLE || ot == LDOUBLE) 3931 convert_constant_floating(op, arg, ot, tp, nt, v, nv); 3932 else if (!convert_constant_to_floating(nt, nv, ot, v)) { 3933 range_check = true; /* Check for lost precision. */ 3934 nv->u.integer = v->u.integer; 3935 } 3936 3937 if (allow_trad && allow_c90 && v->v_unsigned_since_c90 && 3938 (is_floating(nt) || ( 3939 (is_integer(nt) && !is_uinteger(nt) && 3940 portable_rank_cmp(nt, ot) > 0)))) { 3941 /* ANSI C treats constant as unsigned */ 3942 warning(157); 3943 v->v_unsigned_since_c90 = false; 3944 } 3945 3946 if (is_integer(nt)) { 3947 nv->u.integer = convert_integer(nv->u.integer, nt, 3948 tp->t_bitfield ? tp->t_bit_field_width : size_in_bits(nt)); 3949 } 3950 3951 if (range_check && op != CVT) 3952 convert_constant_check_range(ot, tp, nt, op, arg, v, nv); 3953 } 3954 3955 /* 3956 * Create a constant node for sizeof. 3957 */ 3958 tnode_t * 3959 build_sizeof(const type_t *tp) 3960 { 3961 unsigned int size_in_bytes = type_size_in_bits(tp) / CHAR_SIZE; 3962 tnode_t *tn = build_integer_constant(SIZEOF_TSPEC, size_in_bytes); 3963 tn->tn_system_dependent = true; 3964 debug_step("build_sizeof '%s' = %u", type_name(tp), size_in_bytes); 3965 return tn; 3966 } 3967 3968 /* 3969 * Create a constant node for offsetof. 3970 */ 3971 /* ARGSUSED */ /* FIXME: See implementation comments. */ 3972 tnode_t * 3973 build_offsetof(const type_t *tp, const sym_t *sym) 3974 { 3975 3976 if (!is_struct_or_union(tp->t_tspec)) 3977 /* unacceptable operand of '%s' */ 3978 error(111, "offsetof"); 3979 3980 /* FIXME: Don't wrongly use the size of the whole type, use sym. */ 3981 unsigned int offset_in_bytes = type_size_in_bits(tp) / CHAR_SIZE; 3982 tnode_t *tn = build_integer_constant(SIZEOF_TSPEC, offset_in_bytes); 3983 tn->tn_system_dependent = true; 3984 return tn; 3985 } 3986 3987 unsigned int 3988 type_size_in_bits(const type_t *tp) 3989 { 3990 3991 unsigned int elem = 1; 3992 bool flex = false; 3993 lint_assert(tp != NULL); 3994 while (tp->t_tspec == ARRAY) { 3995 flex = true; /* allow c99 flex arrays [] [0] */ 3996 elem *= tp->t_dim; 3997 tp = tp->t_subt; 3998 } 3999 if (elem == 0 && !flex) { 4000 /* cannot take size/alignment of incomplete type */ 4001 error(143); 4002 elem = 1; 4003 } 4004 4005 unsigned int elsz; 4006 switch (tp->t_tspec) { 4007 case VOID: 4008 /* cannot take size/alignment of void */ 4009 error(146); 4010 elsz = 1; 4011 break; 4012 case FUNC: 4013 /* cannot take size/alignment of function type '%s' */ 4014 error(144, type_name(tp)); 4015 elsz = 1; 4016 break; 4017 case STRUCT: 4018 case UNION: 4019 if (is_incomplete(tp)) { 4020 /* cannot take size/alignment of incomplete type */ 4021 error(143); 4022 elsz = 1; 4023 } else { 4024 elsz = tp->t_sou->sou_size_in_bits; 4025 } 4026 break; 4027 case ENUM: 4028 if (is_incomplete(tp)) { 4029 /* cannot take size/alignment of incomplete type */ 4030 warning(143); 4031 } 4032 /* FALLTHROUGH */ 4033 default: 4034 if (tp->t_bitfield) { 4035 /* cannot take size/alignment of bit-field */ 4036 error(145); 4037 } 4038 elsz = size_in_bits(tp->t_tspec); 4039 lint_assert(elsz > 0); 4040 break; 4041 } 4042 4043 return elem * elsz; 4044 } 4045 4046 /* C11 6.5.3.4, GCC */ 4047 tnode_t * 4048 build_alignof(const type_t *tp) 4049 { 4050 if (tp->t_tspec == FUNC) { 4051 /* cannot take size/alignment of function type '%s' */ 4052 error(144, type_name(tp)); 4053 return NULL; 4054 } 4055 if (tp->t_tspec == VOID) { 4056 /* cannot take size/alignment of void */ 4057 error(146); 4058 return NULL; 4059 } 4060 if (is_incomplete(tp)) { 4061 /* cannot take size/alignment of incomplete type */ 4062 error(143); 4063 return NULL; 4064 } 4065 if (tp->t_bitfield) { 4066 /* cannot take size/alignment of bit-field */ 4067 error(145); 4068 return NULL; 4069 } 4070 return build_integer_constant(SIZEOF_TSPEC, 4071 (int64_t)alignment_in_bits(tp) / CHAR_SIZE); 4072 } 4073 4074 static tnode_t * 4075 cast_to_union(tnode_t *otn, type_t *ntp) 4076 { 4077 4078 if (!allow_gcc) { 4079 /* union cast is a GCC extension */ 4080 error(328); 4081 return NULL; 4082 } 4083 4084 for (const sym_t *m = ntp->t_sou->sou_first_member; 4085 m != NULL; m = m->s_next) { 4086 if (types_compatible(m->s_type, otn->tn_type, 4087 false, false, NULL)) { 4088 tnode_t *ntn = expr_alloc_tnode(); 4089 ntn->tn_op = CVT; 4090 ntn->tn_type = ntp; 4091 ntn->tn_cast = true; 4092 ntn->tn_left = otn; 4093 ntn->tn_right = NULL; 4094 return ntn; 4095 } 4096 } 4097 4098 /* type '%s' is not a member of '%s' */ 4099 error(329, type_name(otn->tn_type), type_name(ntp)); 4100 return NULL; 4101 } 4102 4103 /* 4104 * Type casts. 4105 */ 4106 tnode_t * 4107 cast(tnode_t *tn, type_t *tp) 4108 { 4109 4110 if (tn == NULL) 4111 return NULL; 4112 4113 tn = cconv(tn); 4114 4115 lint_assert(tp != NULL); 4116 tspec_t nt = tp->t_tspec; 4117 tspec_t ot = tn->tn_type->t_tspec; 4118 4119 if (nt == VOID) { 4120 /* 4121 * C90 6.3.4, C99 6.5.4p2 and C11 6.5.4p2 allow any type to 4122 * be cast to void. The only other allowed casts are from a 4123 * scalar type to a scalar type. 4124 */ 4125 } else if (nt == UNION) 4126 return cast_to_union(tn, tp); 4127 else if (nt == STRUCT || nt == ARRAY || nt == FUNC) { 4128 /* Casting to a struct is an undocumented GCC extension. */ 4129 if (!(allow_gcc && nt == STRUCT)) 4130 goto invalid_cast; 4131 } else if (is_struct_or_union(ot)) 4132 goto invalid_cast; 4133 else if (ot == VOID) { 4134 /* improper cast of void expression */ 4135 error(148); 4136 return NULL; 4137 } else if (is_integer(nt) && is_scalar(ot)) { 4138 /* ok */ 4139 } else if (is_floating(nt) && is_arithmetic(ot)) { 4140 /* ok */ 4141 } else if (nt == PTR && is_integer(ot)) { 4142 /* ok */ 4143 } else if (nt == PTR && ot == PTR) { 4144 if (!tp->t_subt->t_const && tn->tn_type->t_subt->t_const) { 4145 if (hflag) 4146 /* cast discards 'const' from type '%s' */ 4147 warning(275, type_name(tn->tn_type)); 4148 } 4149 } else 4150 goto invalid_cast; 4151 4152 if (any_query_enabled && types_compatible(tp, tn->tn_type, 4153 false, false, NULL)) { 4154 /* no-op cast from '%s' to '%s' */ 4155 query_message(6, type_name(tn->tn_type), type_name(tp)); 4156 } 4157 4158 tn = convert(CVT, 0, tp, tn); 4159 tn->tn_cast = true; 4160 4161 return tn; 4162 4163 invalid_cast: 4164 /* invalid cast from '%s' to '%s' */ 4165 error(147, type_name(tn->tn_type), type_name(tp)); 4166 return NULL; 4167 } 4168 4169 /* 4170 * Create the node for a function argument. 4171 * All necessary conversions and type checks are done in 4172 * build_function_call because build_function_argument has no 4173 * information about expected argument types. 4174 */ 4175 tnode_t * 4176 build_function_argument(tnode_t *args, tnode_t *arg) 4177 { 4178 /* 4179 * If there was a serious error in the expression for the argument, 4180 * create a dummy argument so the positions of the remaining arguments 4181 * will not change. 4182 */ 4183 if (arg == NULL) 4184 arg = build_integer_constant(INT, 0); 4185 4186 return new_tnode(PUSH, arg->tn_sys, arg->tn_type, arg, args); 4187 } 4188 4189 /* 4190 * Compare the type of an argument with the corresponding type of a 4191 * prototype parameter. If it is a valid combination, but both types 4192 * are not the same, insert a conversion to convert the argument into 4193 * the type of the parameter. 4194 */ 4195 static tnode_t * 4196 check_prototype_argument( 4197 int n, /* pos of arg */ 4198 type_t *tp, /* expected type (from prototype) */ 4199 tnode_t *tn) /* argument */ 4200 { 4201 tnode_t *ln = xcalloc(1, sizeof(*ln)); 4202 ln->tn_type = expr_unqualified_type(tp); 4203 ln->tn_lvalue = true; 4204 if (typeok(FARG, n, ln, tn)) { 4205 bool dowarn; 4206 if (!types_compatible(tp, tn->tn_type, 4207 true, false, (dowarn = false, &dowarn)) || dowarn) 4208 tn = convert(FARG, n, tp, tn); 4209 } 4210 free(ln); 4211 return tn; 4212 } 4213 4214 /* 4215 * Check types of all function arguments and insert conversions, 4216 * if necessary. 4217 */ 4218 static tnode_t * 4219 check_function_arguments(type_t *ftp, tnode_t *args) 4220 { 4221 /* get # of parameters in the prototype */ 4222 int npar = 0; 4223 for (sym_t *asym = ftp->t_args; asym != NULL; asym = asym->s_next) 4224 npar++; 4225 4226 /* get # of arguments in the function call */ 4227 int narg = 0; 4228 for (tnode_t *arg = args; arg != NULL; arg = arg->tn_right) 4229 narg++; 4230 4231 sym_t *asym = ftp->t_args; 4232 if (ftp->t_proto && npar != narg && !(ftp->t_vararg && npar < narg)) { 4233 /* argument mismatch: %d %s passed, %d expected */ 4234 error(150, narg, narg > 1 ? "arguments" : "argument", npar); 4235 asym = NULL; 4236 } 4237 4238 for (int n = 1; n <= narg; n++) { 4239 4240 /* 4241 * The rightmost argument is at the top of the argument 4242 * subtree. 4243 */ 4244 tnode_t *arg = args; 4245 for (int i = narg; i > n; i--, arg = arg->tn_right) 4246 continue; 4247 4248 /* some things which are always not allowed */ 4249 tspec_t at = arg->tn_left->tn_type->t_tspec; 4250 if (at == VOID) { 4251 /* void expressions may not be arguments, arg #%d */ 4252 error(151, n); 4253 return NULL; 4254 } else if (is_struct_or_union(at) && 4255 is_incomplete(arg->tn_left->tn_type)) { 4256 /* argument cannot have unknown size, arg #%d */ 4257 error(152, n); 4258 return NULL; 4259 } else if (is_integer(at) && 4260 arg->tn_left->tn_type->t_is_enum && 4261 is_incomplete(arg->tn_left->tn_type)) { 4262 /* argument cannot have unknown size, arg #%d */ 4263 warning(152, n); 4264 } 4265 4266 /* class conversions (arg in value context) */ 4267 arg->tn_left = cconv(arg->tn_left); 4268 4269 if (asym != NULL) { 4270 arg->tn_left = check_prototype_argument( 4271 n, asym->s_type, arg->tn_left); 4272 } else 4273 arg->tn_left = promote(NOOP, true, arg->tn_left); 4274 arg->tn_type = arg->tn_left->tn_type; 4275 4276 if (asym != NULL) 4277 asym = asym->s_next; 4278 } 4279 4280 return args; 4281 } 4282 4283 /* 4284 * Create the node for a function call. Also check types of 4285 * function arguments and insert conversions, if necessary. 4286 */ 4287 tnode_t * 4288 build_function_call(tnode_t *func, bool sys, tnode_t *args) 4289 { 4290 4291 if (func == NULL) 4292 return NULL; 4293 4294 op_t fcop = func->tn_op == NAME && func->tn_type->t_tspec == FUNC 4295 ? CALL : ICALL; 4296 4297 check_ctype_function_call(func, args); 4298 4299 /* Turn the function name into a pointer to the function. */ 4300 func = cconv(func); 4301 4302 if (func->tn_type->t_tspec != PTR || 4303 func->tn_type->t_subt->t_tspec != FUNC) { 4304 /* cannot call '%s', must be a function */ 4305 error(149, type_name(func->tn_type)); 4306 return NULL; 4307 } 4308 4309 args = check_function_arguments(func->tn_type->t_subt, args); 4310 4311 return new_tnode(fcop, sys, func->tn_type->t_subt->t_subt, func, args); 4312 } 4313 4314 /* 4315 * Return the value of an integral constant expression. 4316 * If the expression is not constant or its type is not an integer 4317 * type, an error message is printed. 4318 */ 4319 val_t * 4320 integer_constant(tnode_t *tn, bool required) 4321 { 4322 4323 if (tn != NULL) 4324 tn = cconv(tn); 4325 if (tn != NULL) 4326 tn = promote(NOOP, false, tn); 4327 4328 val_t *v = xcalloc(1, sizeof(*v)); 4329 4330 if (tn == NULL) { 4331 lint_assert(seen_error); 4332 debug_step("constant node is null; returning 1 instead"); 4333 v->v_tspec = INT; 4334 v->u.integer = 1; 4335 return v; 4336 } 4337 4338 v->v_tspec = tn->tn_type->t_tspec; 4339 4340 if (tn->tn_op == CON) { 4341 lint_assert(tn->tn_type->t_tspec == tn->tn_val.v_tspec); 4342 if (is_integer(tn->tn_val.v_tspec)) { 4343 v->v_unsigned_since_c90 = 4344 tn->tn_val.v_unsigned_since_c90; 4345 v->u.integer = tn->tn_val.u.integer; 4346 return v; 4347 } 4348 v->u.integer = (int64_t)tn->tn_val.u.floating; 4349 } else { 4350 v->u.integer = 1; 4351 } 4352 4353 if (required) 4354 /* integral constant expression expected */ 4355 error(55); 4356 else 4357 /* variable array dimension is a C99/GCC extension */ 4358 c99ism(318); 4359 4360 if (!is_integer(v->v_tspec)) 4361 v->v_tspec = INT; 4362 4363 return v; 4364 } 4365 4366 static bool 4367 is_constcond_false(const tnode_t *tn, tspec_t t) 4368 { 4369 return (t == BOOL || t == INT) && 4370 tn->tn_op == CON && tn->tn_val.u.integer == 0; 4371 } 4372 4373 /* 4374 * Perform some tests on expressions which can't be done in build_binary() 4375 * and functions called by build_binary(). These tests must be done here 4376 * because we need some information about the context in which the operations 4377 * are performed. 4378 * After all tests are performed and dofreeblk is true, expr() frees the 4379 * memory which is used for the expression. 4380 */ 4381 void 4382 expr(tnode_t *tn, bool vctx, bool cond, bool dofreeblk, bool is_do_while) 4383 { 4384 4385 if (tn == NULL) { /* in case of errors */ 4386 expr_free_all(); 4387 return; 4388 } 4389 4390 /* expr() is also called in global initializations */ 4391 if (dcs->d_kind != DLK_EXTERN && !is_do_while) 4392 check_statement_reachable(); 4393 4394 check_expr_misc(tn, vctx, cond, !cond, false, false, false); 4395 if (tn->tn_op == ASSIGN && !tn->tn_parenthesized) { 4396 if (hflag && cond) 4397 /* assignment in conditional context */ 4398 warning(159); 4399 } else if (tn->tn_op == CON) { 4400 if (hflag && cond && !suppress_constcond && 4401 !tn->tn_system_dependent && 4402 !(is_do_while && 4403 is_constcond_false(tn, tn->tn_type->t_tspec))) 4404 /* constant in conditional context */ 4405 warning(161); 4406 } 4407 if (!modtab[tn->tn_op].m_has_side_effect) { 4408 /* 4409 * for left operands of COMMA this warning is already 4410 * printed 4411 */ 4412 if (tn->tn_op != COMMA && !vctx && !cond) 4413 check_null_effect(tn); 4414 } 4415 debug_node(tn); 4416 4417 /* free the tree memory */ 4418 if (dofreeblk) 4419 expr_free_all(); 4420 } 4421 4422 /* 4423 * Checks the range of array indices, if possible. 4424 * amper is set if only the address of the element is used. This 4425 * means that the index is allowed to refer to the first element 4426 * after the array. 4427 */ 4428 static void 4429 check_array_index(tnode_t *tn, bool amper) 4430 { 4431 const tnode_t *ln = tn->tn_left; 4432 const tnode_t *rn = tn->tn_right; 4433 4434 /* We can only check constant indices. */ 4435 if (rn->tn_op != CON) 4436 return; 4437 4438 /* Return if the left node does not stem from an array. */ 4439 if (ln->tn_op != ADDR) 4440 return; 4441 if (ln->tn_left->tn_op != STRING && ln->tn_left->tn_op != NAME) 4442 return; 4443 if (ln->tn_left->tn_type->t_tspec != ARRAY) 4444 return; 4445 4446 /* 4447 * For incomplete array types, we can print a warning only if 4448 * the index is negative. 4449 */ 4450 if (is_incomplete(ln->tn_left->tn_type) && rn->tn_val.u.integer >= 0) 4451 return; 4452 4453 /* Get the size of one array element */ 4454 int elsz = length_in_bits(ln->tn_type->t_subt, NULL); 4455 if (elsz == 0) 4456 return; 4457 elsz /= CHAR_SIZE; 4458 4459 /* Change the unit of the index from bytes to element size. */ 4460 int64_t con = is_uinteger(rn->tn_type->t_tspec) 4461 ? (int64_t)((uint64_t)rn->tn_val.u.integer / elsz) 4462 : rn->tn_val.u.integer / elsz; 4463 4464 int dim = ln->tn_left->tn_type->t_dim + (amper ? 1 : 0); 4465 4466 if (!is_uinteger(rn->tn_type->t_tspec) && con < 0) { 4467 /* array subscript cannot be negative: %ld */ 4468 warning(167, (long)con); 4469 } else if (dim > 0 && (uint64_t)con >= (uint64_t)dim) { 4470 /* array subscript cannot be > %d: %ld */ 4471 warning(168, dim - 1, (long)con); 4472 } 4473 } 4474 4475 static void 4476 check_expr_addr(const tnode_t *ln, bool szof, bool fcall) 4477 { 4478 /* XXX: Taking warn_about_unreachable into account here feels wrong. */ 4479 if (ln->tn_op == NAME && (reached || !warn_about_unreachable)) { 4480 if (!szof) 4481 mark_as_set(ln->tn_sym); 4482 mark_as_used(ln->tn_sym, fcall, szof); 4483 } 4484 if (ln->tn_op == INDIR && ln->tn_left->tn_op == PLUS) 4485 /* check the range of array indices */ 4486 check_array_index(ln->tn_left, true); 4487 } 4488 4489 static void 4490 check_expr_load(const tnode_t *ln) 4491 { 4492 if (ln->tn_op == INDIR && ln->tn_left->tn_op == PLUS) 4493 /* check the range of array indices */ 4494 check_array_index(ln->tn_left, false); 4495 } 4496 4497 /* 4498 * If there is an asm statement in one of the compound statements around, 4499 * there may be other side effects, so don't warn. 4500 */ 4501 static bool 4502 is_asm_around(void) 4503 { 4504 for (decl_level *dl = dcs; dl != NULL; dl = dl->d_enclosing) 4505 if (dl->d_asm) 4506 return true; 4507 return false; 4508 } 4509 4510 static void 4511 check_expr_side_effect(const tnode_t *ln, bool szof) 4512 { 4513 4514 /* XXX: Taking warn_about_unreachable into account here feels wrong. */ 4515 if (ln->tn_op == NAME && (reached || !warn_about_unreachable)) { 4516 scl_t sc = ln->tn_sym->s_scl; 4517 if (sc != EXTERN && sc != STATIC && 4518 !ln->tn_sym->s_set && !szof && !is_asm_around()) { 4519 /* '%s' may be used before set */ 4520 warning(158, ln->tn_sym->s_name); 4521 mark_as_set(ln->tn_sym); 4522 } 4523 mark_as_used(ln->tn_sym, false, false); 4524 } 4525 } 4526 4527 static void 4528 check_expr_assign(const tnode_t *ln, bool szof) 4529 { 4530 /* XXX: Taking warn_about_unreachable into account here feels wrong. */ 4531 if (ln->tn_op == NAME && !szof && (reached || !warn_about_unreachable)) { 4532 mark_as_set(ln->tn_sym); 4533 if (ln->tn_sym->s_scl == EXTERN) 4534 outusg(ln->tn_sym); 4535 } 4536 if (ln->tn_op == INDIR && ln->tn_left->tn_op == PLUS) 4537 /* check the range of array indices */ 4538 check_array_index(ln->tn_left, false); 4539 } 4540 4541 static void 4542 check_expr_call(const tnode_t *tn, const tnode_t *ln, 4543 bool szof, bool vctx, bool cond, bool retval_discarded) 4544 { 4545 lint_assert(ln->tn_op == ADDR); 4546 lint_assert(ln->tn_left->tn_op == NAME); 4547 if (!szof && !is_compiler_builtin(ln->tn_left->tn_sym->s_name)) 4548 outcall(tn, vctx || cond, retval_discarded); 4549 } 4550 4551 static bool 4552 check_expr_op(const tnode_t *tn, op_t op, const tnode_t *ln, 4553 bool szof, bool fcall, bool vctx, bool cond, 4554 bool retval_discarded, bool eqwarn) 4555 { 4556 switch (op) { 4557 case ADDR: 4558 check_expr_addr(ln, szof, fcall); 4559 break; 4560 case LOAD: 4561 check_expr_load(ln); 4562 /* FALLTHROUGH */ 4563 case PUSH: 4564 case INCBEF: 4565 case DECBEF: 4566 case INCAFT: 4567 case DECAFT: 4568 case ADDASS: 4569 case SUBASS: 4570 case MULASS: 4571 case DIVASS: 4572 case MODASS: 4573 case ANDASS: 4574 case ORASS: 4575 case XORASS: 4576 case SHLASS: 4577 case SHRASS: 4578 case REAL: 4579 case IMAG: 4580 check_expr_side_effect(ln, szof); 4581 break; 4582 case ASSIGN: 4583 check_expr_assign(ln, szof); 4584 break; 4585 case CALL: 4586 check_expr_call(tn, ln, szof, vctx, cond, retval_discarded); 4587 break; 4588 case EQ: 4589 if (hflag && eqwarn) 4590 /* operator '==' found where '=' was expected */ 4591 warning(160); 4592 break; 4593 case CON: 4594 case NAME: 4595 case STRING: 4596 return false; 4597 default: 4598 break; 4599 } 4600 return true; 4601 } 4602 4603 /* 4604 * vctx ??? 4605 * cond whether the expression is a condition that 4606 * will be compared with 0 4607 * eqwarn whether the operator '==' might be a 4608 * misspelled '=' 4609 * fcall whether the expression is a function call 4610 * retval_discarded whether the return value of a function call 4611 * is discarded; such calls will be analyzed by 4612 * lint2 in messages 4, 8 and 9 4613 * szof whether the expression is part of a sizeof 4614 * expression, which means that its value is 4615 * discarded since only the type is relevant 4616 */ 4617 void 4618 check_expr_misc(const tnode_t *tn, bool vctx, bool cond, 4619 bool eqwarn, bool fcall, bool retval_discarded, bool szof) 4620 { 4621 4622 if (tn == NULL) 4623 return; 4624 4625 tnode_t *ln = tn->tn_left; 4626 tnode_t *rn = tn->tn_right; 4627 op_t op = tn->tn_op; 4628 const mod_t *mp = &modtab[op]; 4629 4630 if (!check_expr_op(tn, op, ln, 4631 szof, fcall, vctx, cond, retval_discarded, eqwarn)) 4632 return; 4633 4634 bool cvctx = mp->m_value_context; 4635 bool ccond = mp->m_compares_with_zero; 4636 bool eq = mp->m_warn_if_operand_eq && 4637 !ln->tn_parenthesized && 4638 rn != NULL && !rn->tn_parenthesized; 4639 4640 /* 4641 * values of operands of ':' are not used if the type of at least 4642 * one of the operands (for gcc compatibility) is void 4643 * XXX test/value context of QUEST should probably be used as 4644 * context for both operands of COLON 4645 */ 4646 if (op == COLON && tn->tn_type->t_tspec == VOID) 4647 cvctx = ccond = false; 4648 bool discard = op == CVT && tn->tn_type->t_tspec == VOID; 4649 check_expr_misc(ln, cvctx, ccond, eq, op == CALL, discard, szof); 4650 4651 switch (op) { 4652 case PUSH: 4653 if (rn != NULL) 4654 check_expr_misc(rn, false, false, eq, false, false, 4655 szof); 4656 break; 4657 case LOGAND: 4658 case LOGOR: 4659 check_expr_misc(rn, false, true, eq, false, false, szof); 4660 break; 4661 case COLON: 4662 check_expr_misc(rn, cvctx, ccond, eq, false, false, szof); 4663 break; 4664 case COMMA: 4665 check_expr_misc(rn, vctx, cond, false, false, false, szof); 4666 break; 4667 default: 4668 if (mp->m_binary) 4669 check_expr_misc(rn, true, false, eq, false, false, 4670 szof); 4671 break; 4672 } 4673 } 4674 4675 /* 4676 * Return whether the expression can be used for static initialization. 4677 * 4678 * Constant initialization expressions must be constant or an address 4679 * of a static object with an optional offset. In the first case, 4680 * the result is returned in *offsp. In the second case, the static 4681 * object is returned in *symp and the offset in *offsp. 4682 * 4683 * The expression can consist of PLUS, MINUS, ADDR, NAME, STRING and 4684 * CON. Type conversions are allowed if they do not change binary 4685 * representation (including width). 4686 * 4687 * C99 6.6 "Constant expressions" 4688 * C99 6.7.8p4 restricts initializers for static storage duration 4689 */ 4690 bool 4691 constant_addr(const tnode_t *tn, const sym_t **symp, ptrdiff_t *offsp) 4692 { 4693 const sym_t *sym; 4694 ptrdiff_t offs1, offs2; 4695 tspec_t t, ot; 4696 4697 switch (tn->tn_op) { 4698 case MINUS: 4699 if (tn->tn_right->tn_op == CVT) 4700 return constant_addr(tn->tn_right, symp, offsp); 4701 else if (tn->tn_right->tn_op != CON) 4702 return false; 4703 /* FALLTHROUGH */ 4704 case PLUS: 4705 offs1 = offs2 = 0; 4706 if (tn->tn_left->tn_op == CON) { 4707 offs1 = (ptrdiff_t)tn->tn_left->tn_val.u.integer; 4708 if (!constant_addr(tn->tn_right, &sym, &offs2)) 4709 return false; 4710 } else if (tn->tn_right->tn_op == CON) { 4711 offs2 = (ptrdiff_t)tn->tn_right->tn_val.u.integer; 4712 if (tn->tn_op == MINUS) 4713 offs2 = -offs2; 4714 if (!constant_addr(tn->tn_left, &sym, &offs1)) 4715 return false; 4716 } else { 4717 return false; 4718 } 4719 *symp = sym; 4720 *offsp = offs1 + offs2; 4721 return true; 4722 case ADDR: 4723 if (tn->tn_left->tn_op == NAME) { 4724 *symp = tn->tn_left->tn_sym; 4725 *offsp = 0; 4726 return true; 4727 } else { 4728 /* 4729 * If this were the front end of a compiler, we 4730 * would return a label instead of 0, at least if 4731 * 'tn->tn_left->tn_op == STRING'. 4732 */ 4733 *symp = NULL; 4734 *offsp = 0; 4735 return true; 4736 } 4737 case CVT: 4738 t = tn->tn_type->t_tspec; 4739 ot = tn->tn_left->tn_type->t_tspec; 4740 if ((!is_integer(t) && t != PTR) || 4741 (!is_integer(ot) && ot != PTR)) { 4742 return false; 4743 } 4744 #if 0 4745 /* 4746 * consider: 4747 * struct foo { 4748 * unsigned char a; 4749 * } f = { 4750 * (unsigned char)(unsigned long) 4751 * (&(((struct foo *)0)->a)) 4752 * }; 4753 * since psize(unsigned long) != psize(unsigned char), 4754 * this fails. 4755 */ 4756 else if (psize(t) != psize(ot)) 4757 return -1; 4758 #endif 4759 return constant_addr(tn->tn_left, symp, offsp); 4760 default: 4761 return false; 4762 } 4763 } 4764 4765 /* Append s2 to s1, then free s2. */ 4766 strg_t * 4767 cat_strings(strg_t *s1, strg_t *s2) 4768 { 4769 4770 if (s1->st_char != s2->st_char) { 4771 /* cannot concatenate wide and regular string literals */ 4772 error(292); 4773 return s1; 4774 } 4775 4776 size_t len1 = s1->st_len; 4777 size_t len2 = s2->st_len; 4778 size_t chsize = s1->st_char ? sizeof(char) : sizeof(wchar_t); 4779 size_t size1 = len1 * chsize; 4780 size_t size2 = (len2 + 1) * chsize; 4781 s1->st_mem = xrealloc(s1->st_mem, size1 + size2); 4782 memcpy((char *)s1->st_mem + size1, s2->st_mem, size2); 4783 free(s2->st_mem); 4784 4785 s1->st_len = len1 + len2; 4786 free(s2); 4787 4788 return s1; 4789 } 4790 4791 4792 typedef struct stmt_expr { 4793 memory_pool se_mem; 4794 sym_t *se_sym; 4795 struct stmt_expr *se_enclosing; 4796 } stmt_expr; 4797 4798 static stmt_expr *stmt_exprs; 4799 4800 void 4801 begin_statement_expr(void) 4802 { 4803 stmt_expr *se = xmalloc(sizeof(*se)); 4804 se->se_mem = expr_save_memory(); 4805 se->se_sym = NULL; 4806 se->se_enclosing = stmt_exprs; 4807 stmt_exprs = se; 4808 } 4809 4810 void 4811 do_statement_expr(tnode_t *tn) 4812 { 4813 block_level--; 4814 mem_block_level--; 4815 stmt_exprs->se_sym = tn != NULL 4816 ? mktempsym(block_dup_type(tn->tn_type)) 4817 : NULL; /* after a syntax error */ 4818 mem_block_level++; 4819 block_level++; 4820 /* '({ ... })' is a GCC extension */ 4821 gnuism(320); 4822 } 4823 4824 tnode_t * 4825 end_statement_expr(void) 4826 { 4827 stmt_expr *se = stmt_exprs; 4828 if (se->se_sym == NULL) 4829 return NULL; /* after a syntax error */ 4830 tnode_t *tn = build_name(se->se_sym, false); 4831 (void)expr_save_memory(); /* leak */ 4832 expr_restore_memory(se->se_mem); 4833 stmt_exprs = se->se_enclosing; 4834 free(se); 4835 return tn; 4836 } 4837
Indexes created Mon Sep 22 21:09:42 GMT 2025