tree.c revision 1.585
1 /* $NetBSD: tree.c,v 1.585 2023/12/03 12:24:49 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 1.585 2023/12/03 12:24:49 rillig Exp $"); 41 #endif 42 43 #include <float.h> 44 #include <limits.h> 45 #include <math.h> 46 #include <signal.h> 47 #include <stdlib.h> 48 #include <string.h> 49 50 #include "lint1.h" 51 52 53 typedef struct integer_constraints { 54 int64_t smin; /* signed minimum */ 55 int64_t smax; /* signed maximum */ 56 uint64_t umin; /* unsigned minimum */ 57 uint64_t umax; /* unsigned maximum */ 58 uint64_t bset; /* bits that are definitely set */ 59 uint64_t bclr; /* bits that are definitely clear */ 60 } integer_constraints; 61 62 63 static uint64_t 64 u64_fill_right(uint64_t x) 65 { 66 x |= x >> 1; 67 x |= x >> 2; 68 x |= x >> 4; 69 x |= x >> 8; 70 x |= x >> 16; 71 x |= x >> 32; 72 return x; 73 } 74 75 static bool 76 str_ends_with(const char *haystack, const char *needle) 77 { 78 size_t hlen = strlen(haystack); 79 size_t nlen = strlen(needle); 80 81 return nlen <= hlen && 82 memcmp(haystack + hlen - nlen, needle, nlen) == 0; 83 } 84 85 static unsigned 86 width_in_bits(const type_t *tp) 87 { 88 89 lint_assert(is_integer(tp->t_tspec)); 90 return tp->t_bitfield 91 ? tp->t_bit_field_width 92 : size_in_bits(tp->t_tspec); 93 } 94 95 static int 96 portable_rank_cmp(tspec_t t1, tspec_t t2) 97 { 98 const ttab_t *p1 = type_properties(t1), *p2 = type_properties(t2); 99 lint_assert(p1->tt_rank_kind == p2->tt_rank_kind); 100 lint_assert(p1->tt_rank_value > 0); 101 lint_assert(p2->tt_rank_value > 0); 102 return (int)p1->tt_rank_value - (int)p2->tt_rank_value; 103 } 104 105 static bool 106 ic_maybe_signed(const type_t *tp, const integer_constraints *ic) 107 { 108 return !is_uinteger(tp->t_tspec) && ic->bclr >> 63 == 0; 109 } 110 111 static integer_constraints 112 ic_any(const type_t *tp) 113 { 114 integer_constraints c; 115 116 uint64_t vbits = value_bits(width_in_bits(tp)); 117 if (is_uinteger(tp->t_tspec)) { 118 c.smin = INT64_MIN; 119 c.smax = INT64_MAX; 120 c.umin = 0; 121 c.umax = vbits; 122 c.bset = 0; 123 c.bclr = ~c.umax; 124 } else { 125 c.smin = (int64_t)-1 - (int64_t)(vbits >> 1); 126 c.smax = (int64_t)(vbits >> 1); 127 c.umin = 0; 128 c.umax = UINT64_MAX; 129 c.bset = 0; 130 c.bclr = 0; 131 } 132 return c; 133 } 134 135 static integer_constraints 136 ic_con(const type_t *tp, const val_t *v) 137 { 138 integer_constraints c; 139 140 lint_assert(is_integer(tp->t_tspec)); 141 int64_t si = v->u.integer; 142 uint64_t ui = (uint64_t)si; 143 c.smin = si; 144 c.smax = si; 145 c.umin = ui; 146 c.umax = ui; 147 c.bset = ui; 148 c.bclr = ~ui; 149 return c; 150 } 151 152 static integer_constraints 153 ic_cvt(const type_t *ntp, const type_t *otp, integer_constraints a) 154 { 155 unsigned nw = width_in_bits(ntp); 156 unsigned ow = width_in_bits(otp); 157 bool nu = is_uinteger(ntp->t_tspec); 158 bool ou = is_uinteger(otp->t_tspec); 159 160 if (nw >= ow && nu == ou) 161 return a; 162 if (nw > ow && ou) 163 return a; 164 return ic_any(ntp); 165 } 166 167 static integer_constraints 168 ic_bitand(integer_constraints a, integer_constraints b) 169 { 170 integer_constraints c; 171 172 c.smin = INT64_MIN; 173 c.smax = INT64_MAX; 174 c.umin = 0; 175 c.umax = UINT64_MAX; 176 c.bset = a.bset & b.bset; 177 c.bclr = a.bclr | b.bclr; 178 return c; 179 } 180 181 static integer_constraints 182 ic_bitor(integer_constraints a, integer_constraints b) 183 { 184 integer_constraints c; 185 186 c.smin = INT64_MIN; 187 c.smax = INT64_MAX; 188 c.umin = 0; 189 c.umax = UINT64_MAX; 190 c.bset = a.bset | b.bset; 191 c.bclr = a.bclr & b.bclr; 192 return c; 193 } 194 195 static integer_constraints 196 ic_mod(const type_t *tp, integer_constraints a, integer_constraints b) 197 { 198 integer_constraints c; 199 200 if (ic_maybe_signed(tp, &a) || ic_maybe_signed(tp, &b)) 201 return ic_any(tp); 202 203 c.smin = INT64_MIN; 204 c.smax = INT64_MAX; 205 c.umin = 0; 206 c.umax = b.umax - 1; 207 c.bset = 0; 208 c.bclr = ~u64_fill_right(c.umax); 209 return c; 210 } 211 212 static integer_constraints 213 ic_shl(const type_t *tp, integer_constraints a, integer_constraints b) 214 { 215 integer_constraints c; 216 unsigned int amount; 217 218 if (ic_maybe_signed(tp, &a)) 219 return ic_any(tp); 220 221 if (b.smin == b.smax && b.smin >= 0 && b.smin < 64) 222 amount = (unsigned int)b.smin; 223 else if (b.umin == b.umax && b.umin < 64) 224 amount = (unsigned int)b.umin; 225 else 226 return ic_any(tp); 227 228 c.smin = INT64_MIN; 229 c.smax = INT64_MAX; 230 c.umin = 0; 231 c.umax = UINT64_MAX; 232 c.bset = a.bset << amount; 233 c.bclr = a.bclr << amount | (((uint64_t)1 << amount) - 1); 234 return c; 235 } 236 237 static integer_constraints 238 ic_shr(const type_t *tp, integer_constraints a, integer_constraints b) 239 { 240 integer_constraints c; 241 unsigned int amount; 242 243 if (ic_maybe_signed(tp, &a)) 244 return ic_any(tp); 245 246 if (b.smin == b.smax && b.smin >= 0 && b.smin < 64) 247 amount = (unsigned int)b.smin; 248 else if (b.umin == b.umax && b.umin < 64) 249 amount = (unsigned int)b.umin; 250 else 251 return ic_any(tp); 252 253 c.smin = INT64_MIN; 254 c.smax = INT64_MAX; 255 c.umin = 0; 256 c.umax = UINT64_MAX; 257 c.bset = a.bset >> amount; 258 c.bclr = a.bclr >> amount | ~(~(uint64_t)0 >> amount); 259 return c; 260 } 261 262 static integer_constraints 263 ic_cond(integer_constraints a, integer_constraints b) 264 { 265 integer_constraints c; 266 267 c.smin = a.smin < b.smin ? a.smin : b.smin; 268 c.smax = a.smax > b.smax ? a.smax : b.smax; 269 c.umin = a.umin < b.umin ? a.umin : b.umin; 270 c.umax = a.umax > b.umax ? a.umax : b.umax; 271 c.bset = a.bset | b.bset; 272 c.bclr = a.bclr & b.bclr; 273 return c; 274 } 275 276 static integer_constraints 277 ic_expr(const tnode_t *tn) 278 { 279 integer_constraints lc, rc; 280 281 lint_assert(is_integer(tn->tn_type->t_tspec)); 282 283 switch (tn->tn_op) { 284 case CON: 285 return ic_con(tn->tn_type, &tn->tn_val); 286 case CVT: 287 if (!is_integer(tn->tn_left->tn_type->t_tspec)) 288 return ic_any(tn->tn_type); 289 lc = ic_expr(tn->tn_left); 290 return ic_cvt(tn->tn_type, tn->tn_left->tn_type, lc); 291 case MOD: 292 lc = ic_expr(before_conversion(tn->tn_left)); 293 rc = ic_expr(before_conversion(tn->tn_right)); 294 return ic_mod(tn->tn_type, lc, rc); 295 case SHL: 296 lc = ic_expr(tn->tn_left); 297 rc = ic_expr(tn->tn_right); 298 return ic_shl(tn->tn_type, lc, rc); 299 case SHR: 300 lc = ic_expr(tn->tn_left); 301 rc = ic_expr(tn->tn_right); 302 return ic_shr(tn->tn_type, lc, rc); 303 case BITAND: 304 lc = ic_expr(tn->tn_left); 305 rc = ic_expr(tn->tn_right); 306 return ic_bitand(lc, rc); 307 case BITOR: 308 lc = ic_expr(tn->tn_left); 309 rc = ic_expr(tn->tn_right); 310 return ic_bitor(lc, rc); 311 case QUEST: 312 lc = ic_expr(tn->tn_right->tn_left); 313 rc = ic_expr(tn->tn_right->tn_right); 314 return ic_cond(lc, rc); 315 default: 316 return ic_any(tn->tn_type); 317 } 318 } 319 320 /* Build 'pointer to tp', 'array of tp' or 'function returning tp'. */ 321 type_t * 322 block_derive_type(type_t *tp, tspec_t t) 323 { 324 type_t *tp2; 325 326 tp2 = block_zero_alloc(sizeof(*tp2), "type"); 327 tp2->t_tspec = t; 328 tp2->t_subt = tp; 329 return tp2; 330 } 331 332 /* 333 * Derive 'pointer to tp' or 'function returning tp'. 334 * The memory is freed at the end of the current expression. 335 */ 336 type_t * 337 expr_derive_type(type_t *tp, tspec_t t) 338 { 339 type_t *tp2; 340 341 tp2 = expr_zero_alloc(sizeof(*tp2), "type"); 342 tp2->t_tspec = t; 343 tp2->t_subt = tp; 344 return tp2; 345 } 346 347 /* Create an expression from a unary or binary operator and its operands. */ 348 static tnode_t * 349 build_op(op_t op, bool sys, type_t *type, tnode_t *ln, tnode_t *rn) 350 { 351 352 tnode_t *ntn = expr_alloc_tnode(); 353 ntn->tn_op = op; 354 ntn->tn_type = type; 355 ntn->tn_sys = sys; 356 ntn->tn_left = ln; 357 ntn->tn_right = rn; 358 359 if (op == INDIR || op == FSEL) { 360 lint_assert(ln->tn_type->t_tspec == PTR); 361 tspec_t t = ln->tn_type->t_subt->t_tspec; 362 ntn->tn_lvalue = t != FUNC && t != VOID; 363 } 364 365 return ntn; 366 } 367 368 tnode_t * 369 build_constant(type_t *tp, val_t *v) 370 { 371 372 tnode_t *n = expr_alloc_tnode(); 373 n->tn_op = CON; 374 n->tn_type = tp; 375 n->tn_val = *v; 376 n->tn_val.v_tspec = tp->t_tspec; 377 free(v); 378 return n; 379 } 380 381 static tnode_t * 382 build_integer_constant(tspec_t t, int64_t si) 383 { 384 385 tnode_t *n = expr_alloc_tnode(); 386 n->tn_op = CON; 387 n->tn_type = gettyp(t); 388 n->tn_val.v_tspec = t; 389 n->tn_val.v_unsigned_since_c90 = false; 390 n->tn_val.v_char_constant = false; 391 n->tn_val.u.integer = si; 392 return n; 393 } 394 395 static void 396 fallback_symbol(sym_t *sym) 397 { 398 399 if (Tflag && fallback_symbol_strict_bool(sym)) 400 return; 401 402 if (block_level > 0 && (strcmp(sym->s_name, "__FUNCTION__") == 0 || 403 strcmp(sym->s_name, "__PRETTY_FUNCTION__") == 0)) { 404 /* __FUNCTION__/__PRETTY_FUNCTION__ is a GCC extension */ 405 gnuism(316); 406 // XXX: Should probably be ARRAY instead of PTR. 407 sym->s_type = block_derive_type(gettyp(CHAR), PTR); 408 sym->s_type->t_const = true; 409 return; 410 } 411 412 if (block_level > 0 && strcmp(sym->s_name, "__func__") == 0) { 413 if (!allow_c99) 414 /* __func__ is a C99 feature */ 415 warning(317); 416 /* C11 6.4.2.2 */ 417 sym->s_type = block_derive_type(gettyp(CHAR), ARRAY); 418 sym->s_type->t_const = true; 419 sym->s_type->t_dim = (int)strlen(funcsym->s_name) + 1; 420 return; 421 } 422 423 /* '%s' undefined */ 424 error(99, sym->s_name); 425 } 426 427 /* 428 * Functions that are predeclared by GCC or other compilers can be called 429 * with arbitrary arguments. Since lint usually runs after a successful 430 * compilation, it's the compiler's job to catch any errors. 431 */ 432 bool 433 is_compiler_builtin(const char *name) 434 { 435 /* https://gcc.gnu.org/onlinedocs/gcc/C-Extensions.html */ 436 if (allow_gcc) { 437 if (strncmp(name, "__atomic_", 9) == 0 || 438 strncmp(name, "__builtin_", 10) == 0 || 439 strcmp(name, "alloca") == 0 || 440 /* obsolete but still in use, as of 2021 */ 441 strncmp(name, "__sync_", 7) == 0) 442 return true; 443 } 444 445 /* https://software.intel.com/sites/landingpage/IntrinsicsGuide/ */ 446 if (strncmp(name, "_mm_", 4) == 0) 447 return true; 448 449 return false; 450 } 451 452 /* https://gcc.gnu.org/onlinedocs/gcc/Integer-Overflow-Builtins.html */ 453 static bool 454 is_gcc_bool_builtin(const char *name) 455 { 456 return strncmp(name, "__builtin_", 10) == 0 && 457 (str_ends_with(name, "_overflow") || 458 str_ends_with(name, "_overflow_p")); 459 } 460 461 static void 462 build_name_call(sym_t *sym) 463 { 464 465 if (is_compiler_builtin(sym->s_name)) { 466 /* 467 * Do not warn about these, just assume that 468 * they are regular functions compatible with 469 * non-prototype calling conventions. 470 */ 471 if (allow_gcc && is_gcc_bool_builtin(sym->s_name)) 472 sym->s_type = gettyp(BOOL); 473 } else if (allow_c99) { 474 /* function '%s' implicitly declared to return int */ 475 error(215, sym->s_name); 476 } else if (!allow_trad) { 477 /* function '%s' implicitly declared to return int */ 478 warning(215, sym->s_name); 479 } 480 481 /* XXX if !allow_c90, the symbol should be exported to level 0 */ 482 sym->s_type = block_derive_type(sym->s_type, FUNC); 483 } 484 485 /* Create a node for a name (symbol table entry). */ 486 tnode_t * 487 build_name(sym_t *sym, bool is_funcname) 488 { 489 490 if (sym->s_scl == NO_SCL && !in_gcc_attribute) { 491 sym->s_scl = EXTERN; 492 sym->s_def = DECL; 493 if (is_funcname) 494 build_name_call(sym); 495 else 496 fallback_symbol(sym); 497 } 498 499 lint_assert(sym->s_kind == FVFT || sym->s_kind == FMEMBER); 500 501 tnode_t *n = expr_alloc_tnode(); 502 n->tn_type = sym->s_type; 503 if (sym->s_scl == BOOL_CONST) { 504 n->tn_op = CON; 505 n->tn_val.v_tspec = BOOL; 506 n->tn_val.v_unsigned_since_c90 = false; 507 n->tn_val.v_char_constant = false; 508 n->tn_val.u.integer = sym->u.s_bool_constant ? 1 : 0; 509 } else if (sym->s_scl == ENUM_CONST) { 510 n->tn_op = CON; 511 n->tn_val.v_tspec = INT; /* ENUM is in n->tn_type */ 512 n->tn_val.v_unsigned_since_c90 = false; 513 n->tn_val.v_char_constant = false; 514 n->tn_val.u.integer = sym->u.s_enum_constant; 515 } else { 516 n->tn_op = NAME; 517 n->tn_sym = sym; 518 if (sym->s_kind == FVFT && sym->s_type->t_tspec != FUNC) 519 n->tn_lvalue = true; 520 } 521 522 return n; 523 } 524 525 tnode_t * 526 build_string(strg_t *strg) 527 { 528 size_t len = strg->st_len; 529 530 type_t *tp = expr_zero_alloc(sizeof(*tp), "type"); 531 tp->t_tspec = ARRAY; 532 tp->t_subt = gettyp(strg->st_char ? CHAR : WCHAR_TSPEC); 533 tp->t_dim = (int)(len + 1); 534 535 tnode_t *n = expr_alloc_tnode(); 536 n->tn_op = STRING; 537 n->tn_type = tp; 538 n->tn_lvalue = true; 539 540 n->tn_string = expr_zero_alloc(sizeof(*n->tn_string), "type.string"); 541 n->tn_string->st_char = strg->st_char; 542 n->tn_string->st_len = len; 543 544 size_t chsize = strg->st_char ? sizeof(char) : sizeof(wchar_t); 545 size_t size = (len + 1) * chsize; 546 n->tn_string->st_mem = expr_zero_alloc(size, "type.string.data"); 547 (void)memcpy(n->tn_string->st_mem, strg->st_mem, size); 548 free(strg->st_mem); 549 free(strg); 550 551 return n; 552 } 553 554 tnode_t * 555 build_generic_selection(const tnode_t *expr, 556 struct generic_association *sel) 557 { 558 tnode_t *default_result = NULL; 559 560 for (; sel != NULL; sel = sel->ga_prev) { 561 if (expr != NULL && 562 types_compatible(sel->ga_arg, expr->tn_type, 563 false, false, NULL)) 564 return sel->ga_result; 565 else if (sel->ga_arg == NULL) 566 default_result = sel->ga_result; 567 } 568 return default_result; 569 } 570 571 static bool 572 is_out_of_char_range(const tnode_t *tn) 573 { 574 return tn->tn_op == CON && 575 !tn->tn_val.v_char_constant && 576 !(0 <= tn->tn_val.u.integer && 577 tn->tn_val.u.integer < 1 << (CHAR_SIZE - 1)); 578 } 579 580 static bool 581 check_nonportable_char_comparison(op_t op, 582 const tnode_t *ln, tspec_t lt, 583 const tnode_t *rn, tspec_t rt) 584 { 585 if (!(hflag || pflag)) 586 return true; 587 588 if (lt == CHAR && is_out_of_char_range(rn)) { 589 char buf[128]; 590 (void)snprintf(buf, sizeof(buf), "%s %d", 591 op_name(op), (int)rn->tn_val.u.integer); 592 /* nonportable character comparison '%s' */ 593 warning(230, buf); 594 return false; 595 } 596 if (rt == CHAR && is_out_of_char_range(ln)) { 597 char buf[128]; 598 (void)snprintf(buf, sizeof(buf), "%d %s ?", 599 (int)ln->tn_val.u.integer, op_name(op)); 600 /* nonportable character comparison '%s' */ 601 warning(230, buf); 602 return false; 603 } 604 return true; 605 } 606 607 static void 608 check_integer_comparison(op_t op, tnode_t *ln, tnode_t *rn) 609 { 610 611 tspec_t lt = ln->tn_type->t_tspec; 612 tspec_t rt = rn->tn_type->t_tspec; 613 614 if (ln->tn_op != CON && rn->tn_op != CON) 615 return; 616 617 if (!is_integer(lt) || !is_integer(rt)) 618 return; 619 620 if (any_query_enabled && !in_system_header) { 621 if (lt == CHAR && rn->tn_op == CON && 622 !rn->tn_val.v_char_constant) { 623 /* comparison '%s' of 'char' with plain integer %d */ 624 query_message(14, 625 op_name(op), (int)rn->tn_val.u.integer); 626 } 627 if (rt == CHAR && ln->tn_op == CON && 628 !ln->tn_val.v_char_constant) { 629 /* comparison '%s' of 'char' with plain integer %d */ 630 query_message(14, 631 op_name(op), (int)ln->tn_val.u.integer); 632 } 633 } 634 635 if (!check_nonportable_char_comparison(op, ln, lt, rn, rt)) 636 return; 637 638 if (is_uinteger(lt) && !is_uinteger(rt) && 639 rn->tn_op == CON && rn->tn_val.u.integer <= 0) { 640 if (rn->tn_val.u.integer < 0) { 641 /* operator '%s' compares '%s' with '%s' */ 642 warning(162, op_name(op), 643 type_name(ln->tn_type), "negative constant"); 644 } else if (op == LT || op == GE) { 645 /* operator '%s' compares '%s' with '%s' */ 646 warning(162, op_name(op), type_name(ln->tn_type), "0"); 647 } 648 return; 649 } 650 if (is_uinteger(rt) && !is_uinteger(lt) && 651 ln->tn_op == CON && ln->tn_val.u.integer <= 0) { 652 if (ln->tn_val.u.integer < 0) { 653 /* operator '%s' compares '%s' with '%s' */ 654 warning(162, op_name(op), 655 "negative constant", type_name(rn->tn_type)); 656 } else if (op == GT || op == LE) { 657 /* operator '%s' compares '%s' with '%s' */ 658 warning(162, op_name(op), "0", type_name(rn->tn_type)); 659 } 660 return; 661 } 662 } 663 664 static const tspec_t arith_rank[] = { 665 LDOUBLE, DOUBLE, FLOAT, 666 #ifdef INT128_SIZE 667 UINT128, INT128, 668 #endif 669 ULLONG, LLONG, 670 ULONG, LONG, 671 UINT, INT, 672 }; 673 674 /* Keep unsigned in traditional C */ 675 static tspec_t 676 usual_arithmetic_conversion_trad(tspec_t lt, tspec_t rt) 677 { 678 679 size_t i; 680 for (i = 0; arith_rank[i] != INT; i++) 681 if (lt == arith_rank[i] || rt == arith_rank[i]) 682 break; 683 684 tspec_t t = arith_rank[i]; 685 if (is_uinteger(lt) || is_uinteger(rt)) 686 if (is_integer(t) && !is_uinteger(t)) 687 return unsigned_type(t); 688 return t; 689 } 690 691 static tspec_t 692 usual_arithmetic_conversion_c90(tspec_t lt, tspec_t rt) 693 { 694 695 if (lt == rt) 696 return lt; 697 698 if (lt == LCOMPLEX || rt == LCOMPLEX) 699 return LCOMPLEX; 700 if (lt == DCOMPLEX || rt == DCOMPLEX) 701 return DCOMPLEX; 702 if (lt == FCOMPLEX || rt == FCOMPLEX) 703 return FCOMPLEX; 704 if (lt == LDOUBLE || rt == LDOUBLE) 705 return LDOUBLE; 706 if (lt == DOUBLE || rt == DOUBLE) 707 return DOUBLE; 708 if (lt == FLOAT || rt == FLOAT) 709 return FLOAT; 710 711 /* 712 * If type A has more bits than type B, it should be able to hold all 713 * possible values of type B. 714 */ 715 if (size_in_bits(lt) > size_in_bits(rt)) 716 return lt; 717 if (size_in_bits(lt) < size_in_bits(rt)) 718 return rt; 719 720 size_t i; 721 for (i = 3; arith_rank[i] != INT; i++) 722 if (arith_rank[i] == lt || arith_rank[i] == rt) 723 break; 724 if ((is_uinteger(lt) || is_uinteger(rt)) && 725 !is_uinteger(arith_rank[i])) 726 i--; 727 return arith_rank[i]; 728 } 729 730 static tnode_t * 731 apply_usual_arithmetic_conversions(op_t op, tnode_t *tn, tspec_t t) 732 { 733 type_t *ntp = expr_dup_type(tn->tn_type); 734 ntp->t_tspec = t; 735 if (tn->tn_op != CON) { 736 /* usual arithmetic conversion for '%s' from '%s' to '%s' */ 737 query_message(4, op_name(op), 738 type_name(tn->tn_type), type_name(ntp)); 739 } 740 return convert(op, 0, ntp, tn); 741 } 742 743 /* 744 * Apply the "usual arithmetic conversions" (C99 6.3.1.8), which gives both 745 * operands the same type. 746 */ 747 static void 748 balance(op_t op, tnode_t **lnp, tnode_t **rnp) 749 { 750 751 tspec_t lt = (*lnp)->tn_type->t_tspec; 752 tspec_t rt = (*rnp)->tn_type->t_tspec; 753 if (!is_arithmetic(lt) || !is_arithmetic(rt)) 754 return; 755 756 tspec_t t = allow_c90 757 ? usual_arithmetic_conversion_c90(lt, rt) 758 : usual_arithmetic_conversion_trad(lt, rt); 759 760 if (t != lt) 761 *lnp = apply_usual_arithmetic_conversions(op, *lnp, t); 762 if (t != rt) 763 *rnp = apply_usual_arithmetic_conversions(op, *rnp, t); 764 } 765 766 /* 767 * Create a tree node for the unary & operator 768 */ 769 static tnode_t * 770 build_address(bool sys, tnode_t *tn, bool noign) 771 { 772 tspec_t t; 773 774 if (!noign && ((t = tn->tn_type->t_tspec) == ARRAY || t == FUNC)) { 775 if (!allow_c90) 776 /* '&' before array or function: ignored */ 777 warning(127); 778 return tn; 779 } 780 781 /* eliminate &* */ 782 if (tn->tn_op == INDIR && 783 tn->tn_left->tn_type->t_tspec == PTR && 784 tn->tn_left->tn_type->t_subt == tn->tn_type) { 785 return tn->tn_left; 786 } 787 788 return build_op(ADDR, sys, expr_derive_type(tn->tn_type, PTR), 789 tn, NULL); 790 } 791 792 /* 793 * XXX 794 * Note: There appear to be a number of bugs in detecting overflow in 795 * this function. An audit and a set of proper regression tests are needed. 796 * --Perry Metzger, Nov. 16, 2001 797 */ 798 /* 799 * Do only as much as necessary to compute constant expressions. 800 * Called only if the operator allows folding and all operands are constants. 801 */ 802 static tnode_t * 803 fold(tnode_t *tn) 804 { 805 806 val_t *v = xcalloc(1, sizeof(*v)); 807 v->v_tspec = tn->tn_type->t_tspec; 808 809 lint_assert(has_operands(tn)); 810 tspec_t t = tn->tn_left->tn_type->t_tspec; 811 bool utyp = !is_integer(t) || is_uinteger(t); 812 int64_t sl = tn->tn_left->tn_val.u.integer, sr = 0; 813 uint64_t ul = sl, ur = 0; 814 if (is_binary(tn)) 815 ur = sr = tn->tn_right->tn_val.u.integer; 816 817 int64_t mask = (int64_t)value_bits(size_in_bits(t)); 818 bool ovfl = false; 819 820 int64_t si; 821 switch (tn->tn_op) { 822 case UPLUS: 823 si = sl; 824 break; 825 case UMINUS: 826 si = sl == INT64_MIN ? sl : -sl; 827 if (sl != 0 && msb(si, t) == msb(sl, t)) 828 ovfl = true; 829 break; 830 case COMPL: 831 si = ~sl; 832 break; 833 case MULT: 834 if (utyp) { 835 si = (int64_t)(ul * ur); 836 if (si != (si & mask)) 837 ovfl = true; 838 else if ((ul != 0) && ((si / ul) != ur)) 839 ovfl = true; 840 } else { 841 si = sl * sr; 842 if (msb(si, t) != (msb(sl, t) ^ msb(sr, t))) 843 ovfl = true; 844 } 845 break; 846 case DIV: 847 if (sr == 0) { 848 /* division by 0 */ 849 error(139); 850 si = utyp ? -1 : INT64_MAX; 851 } else { 852 si = utyp ? (int64_t)(ul / ur) : sl / sr; 853 } 854 break; 855 case MOD: 856 if (sr == 0) { 857 /* modulus by 0 */ 858 error(140); 859 si = 0; 860 } else { 861 si = utyp ? (int64_t)(ul % ur) : sl % sr; 862 } 863 break; 864 case PLUS: 865 si = utyp ? (int64_t)(ul + ur) : sl + sr; 866 if (msb(sl, t) && msb(sr, t) && !msb(si, t)) 867 ovfl = true; 868 if (!utyp && !msb(sl, t) && !msb(sr, t) && msb(si, t)) 869 ovfl = true; 870 break; 871 case MINUS: 872 si = utyp ? (int64_t)(ul - ur) : sl - sr; 873 if (!utyp && msb(sl, t) && !msb(sr, t) && !msb(si, t)) 874 ovfl = true; 875 if (!msb(sl, t) && msb(sr, t) && msb(si, t)) 876 ovfl = true; 877 break; 878 case SHL: 879 /* TODO: warn about out-of-bounds 'sr'. */ 880 /* TODO: warn about overflow in signed '<<'. */ 881 si = utyp ? (int64_t)(ul << (sr & 63)) : sl << (sr & 63); 882 break; 883 case SHR: 884 /* 885 * The sign must be explicitly extended because 886 * shifts of signed values are implementation dependent. 887 */ 888 /* TODO: warn about out-of-bounds 'sr'. */ 889 si = (int64_t)(ul >> (sr & 63)); 890 si = convert_integer(si, t, size_in_bits(t) - (int)sr); 891 break; 892 case LT: 893 si = (utyp ? ul < ur : sl < sr) ? 1 : 0; 894 break; 895 case LE: 896 si = (utyp ? ul <= ur : sl <= sr) ? 1 : 0; 897 break; 898 case GE: 899 si = (utyp ? ul >= ur : sl >= sr) ? 1 : 0; 900 break; 901 case GT: 902 si = (utyp ? ul > ur : sl > sr) ? 1 : 0; 903 break; 904 case EQ: 905 si = (utyp ? ul == ur : sl == sr) ? 1 : 0; 906 break; 907 case NE: 908 si = (utyp ? ul != ur : sl != sr) ? 1 : 0; 909 break; 910 case BITAND: 911 si = utyp ? (int64_t)(ul & ur) : sl & sr; 912 break; 913 case BITXOR: 914 si = utyp ? (int64_t)(ul ^ ur) : sl ^ sr; 915 break; 916 case BITOR: 917 si = utyp ? (int64_t)(ul | ur) : sl | sr; 918 break; 919 default: 920 lint_assert(/*CONSTCOND*/false); 921 } 922 923 /* XXX: The overflow check does not work for 64-bit integers. */ 924 if (ovfl || 925 ((uint64_t)(si | mask) != ~(uint64_t)0 && (si & ~mask) != 0)) { 926 if (hflag) 927 /* operator '%s' produces integer overflow */ 928 warning(141, op_name(tn->tn_op)); 929 } 930 931 v->u.integer = convert_integer(si, t, 0); 932 933 tnode_t *cn = build_constant(tn->tn_type, v); 934 if (tn->tn_left->tn_system_dependent) 935 cn->tn_system_dependent = true; 936 if (is_binary(tn) && tn->tn_right->tn_system_dependent) 937 cn->tn_system_dependent = true; 938 939 return cn; 940 } 941 942 /* 943 * Create a new node for one of the operators POINT and ARROW. 944 */ 945 static tnode_t * 946 build_struct_access(op_t op, bool sys, tnode_t *ln, tnode_t *rn) 947 { 948 949 lint_assert(rn->tn_op == NAME); 950 lint_assert(is_member(rn->tn_sym)); 951 952 bool lvalue = op == ARROW || ln->tn_lvalue; 953 954 if (op == POINT) { 955 ln = build_address(sys, ln, true); 956 } else if (ln->tn_type->t_tspec != PTR) { 957 lint_assert(!allow_c90); 958 lint_assert(is_integer(ln->tn_type->t_tspec)); 959 ln = convert(NOOP, 0, expr_derive_type(gettyp(VOID), PTR), ln); 960 } 961 962 tnode_t *ctn = build_integer_constant(PTRDIFF_TSPEC, 963 rn->tn_sym->u.s_member.sm_offset_in_bits / CHAR_SIZE); 964 965 type_t *ptr_tp = expr_derive_type(rn->tn_type, PTR); 966 tnode_t *ntn = build_op(PLUS, sys, ptr_tp, ln, ctn); 967 if (ln->tn_op == CON) 968 ntn = fold(ntn); 969 970 op_t nop = rn->tn_type->t_bitfield ? FSEL : INDIR; 971 ntn = build_op(nop, sys, ntn->tn_type->t_subt, ntn, NULL); 972 if (!lvalue) 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 build_op(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 = build_op(MULT, sys, rn->tn_type, rn, elsz); 1129 if (rn->tn_op == CON) 1130 prod = fold(prod); 1131 1132 return build_op(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 = build_op(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 build_op(DIV, sys, ptrdiff, raw_diff, elsz); 1149 } 1150 1151 return build_op(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 // XXX: C1978 7.5 says: "Both [operators] perform the usual 1163 // arithmetic conversions on their operands." 1164 // TODO: Add a test to exercise this part of the code. 1165 rn = convert(NOOP, 0, gettyp(INT), rn); 1166 return build_op(op, sys, ln->tn_type, ln, rn); 1167 } 1168 1169 static bool 1170 is_null_pointer(const tnode_t *tn) 1171 { 1172 tspec_t t = tn->tn_type->t_tspec; 1173 1174 // TODO: Investigate how other pointers are stored, in particular, 1175 // whether a pointer constant can have a non-zero value. 1176 // If not, simplify the code below. 1177 return ((t == PTR && tn->tn_type->t_subt->t_tspec == VOID) 1178 || is_integer(t)) 1179 && (tn->tn_op == CON && tn->tn_val.u.integer == 0); 1180 } 1181 1182 /* Return a type based on tp1, with added qualifiers from tp2. */ 1183 static type_t * 1184 merge_qualifiers(type_t *tp1, const type_t *tp2) 1185 { 1186 1187 lint_assert(tp1->t_tspec == PTR); 1188 lint_assert(tp2->t_tspec == PTR); 1189 1190 bool c1 = tp1->t_subt->t_const; 1191 bool c2 = tp2->t_subt->t_const; 1192 bool v1 = tp1->t_subt->t_volatile; 1193 bool v2 = tp2->t_subt->t_volatile; 1194 1195 if (c1 == (c1 | c2) && v1 == (v1 | v2)) 1196 return tp1; 1197 1198 type_t *nstp = expr_dup_type(tp1->t_subt); 1199 nstp->t_const |= c2; 1200 nstp->t_volatile |= v2; 1201 1202 type_t *ntp = expr_dup_type(tp1); 1203 ntp->t_subt = nstp; 1204 return ntp; 1205 } 1206 1207 /* See C99 6.5.15 "Conditional operator". */ 1208 static tnode_t * 1209 build_colon(bool sys, tnode_t *ln, tnode_t *rn) 1210 { 1211 1212 tspec_t lt = ln->tn_type->t_tspec; 1213 tspec_t rt = rn->tn_type->t_tspec; 1214 1215 type_t *tp; 1216 if (is_arithmetic(lt) && is_arithmetic(rt)) { 1217 /* The operands were already balanced in build_binary. */ 1218 tp = ln->tn_type; 1219 } else if (lt == BOOL && rt == BOOL) { 1220 tp = ln->tn_type; 1221 } else if (lt == VOID || rt == VOID) { 1222 tp = gettyp(VOID); 1223 } else if (is_struct_or_union(lt)) { 1224 /* Both types must be identical. */ 1225 lint_assert(is_struct_or_union(rt)); 1226 lint_assert(ln->tn_type->t_sou == rn->tn_type->t_sou); 1227 if (is_incomplete(ln->tn_type)) { 1228 /* unknown operand size, op '%s' */ 1229 error(138, op_name(COLON)); 1230 return NULL; 1231 } 1232 tp = ln->tn_type; 1233 } else if (lt == PTR && is_integer(rt)) { 1234 if (rt != PTRDIFF_TSPEC) 1235 rn = convert(NOOP, 0, gettyp(PTRDIFF_TSPEC), rn); 1236 tp = ln->tn_type; 1237 } else if (rt == PTR && is_integer(lt)) { 1238 if (lt != PTRDIFF_TSPEC) 1239 ln = convert(NOOP, 0, gettyp(PTRDIFF_TSPEC), ln); 1240 tp = rn->tn_type; 1241 } else if (lt == PTR && is_null_pointer(rn)) { 1242 tp = merge_qualifiers(ln->tn_type, rn->tn_type); 1243 } else if (rt == PTR && is_null_pointer(ln)) { 1244 tp = merge_qualifiers(rn->tn_type, ln->tn_type); 1245 } else if (lt == PTR && ln->tn_type->t_subt->t_tspec == VOID) { 1246 tp = merge_qualifiers(ln->tn_type, rn->tn_type); 1247 } else if (rt == PTR && rn->tn_type->t_subt->t_tspec == VOID) { 1248 tp = merge_qualifiers(rn->tn_type, ln->tn_type); 1249 } else { 1250 /* 1251 * XXX For now we simply take the left type. This is 1252 * probably wrong, if one type contains a function prototype 1253 * and the other one, at the same place, only an old-style 1254 * declaration. 1255 */ 1256 tp = merge_qualifiers(ln->tn_type, rn->tn_type); 1257 } 1258 1259 return build_op(COLON, sys, tp, ln, rn); 1260 } 1261 1262 /* TODO: check for varargs */ 1263 static bool 1264 is_cast_redundant(const tnode_t *tn) 1265 { 1266 const type_t *ntp = tn->tn_type, *otp = tn_ck_left(tn)->tn_type; 1267 tspec_t nt = ntp->t_tspec, ot = otp->t_tspec; 1268 1269 if (nt == BOOL || ot == BOOL) 1270 return nt == BOOL && ot == BOOL; 1271 1272 if (is_integer(nt) && is_integer(ot)) { 1273 unsigned int nw = width_in_bits(ntp), ow = width_in_bits(otp); 1274 if (is_uinteger(nt) == is_uinteger(ot)) 1275 return nw >= ow; 1276 return is_uinteger(ot) && nw > ow; 1277 } 1278 1279 if (is_complex(nt) || is_complex(ot)) 1280 return is_complex(nt) && is_complex(ot) && 1281 size_in_bits(nt) >= size_in_bits(ot); 1282 1283 if (is_floating(nt) && is_floating(ot)) 1284 return size_in_bits(nt) >= size_in_bits(ot); 1285 1286 if (nt == PTR && ot == PTR) { 1287 if (!ntp->t_subt->t_const && otp->t_subt->t_const) 1288 return false; 1289 if (!ntp->t_subt->t_volatile && otp->t_subt->t_volatile) 1290 return false; 1291 1292 if (ntp->t_subt->t_tspec == VOID || 1293 otp->t_subt->t_tspec == VOID || 1294 types_compatible(ntp->t_subt, otp->t_subt, 1295 false, false, NULL)) 1296 return true; 1297 } 1298 1299 return false; 1300 } 1301 1302 static bool 1303 is_assignment(op_t op) 1304 { 1305 1306 return op == ASSIGN || 1307 op == MULASS || 1308 op == DIVASS || 1309 op == MODASS || 1310 op == ADDASS || 1311 op == SUBASS || 1312 op == SHLASS || 1313 op == SHRASS || 1314 op == ANDASS || 1315 op == XORASS || 1316 op == ORASS || 1317 op == RETURN || 1318 op == INIT; 1319 } 1320 1321 /* Create a node for an assignment operator (both '=' and 'op='). */ 1322 static tnode_t * 1323 build_assignment(op_t op, bool sys, tnode_t *ln, tnode_t *rn) 1324 { 1325 1326 tspec_t lt = ln->tn_type->t_tspec; 1327 tspec_t rt = rn->tn_type->t_tspec; 1328 1329 if (any_query_enabled && is_assignment(rn->tn_op)) { 1330 /* chained assignment with '%s' and '%s' */ 1331 query_message(10, op_name(op), op_name(rn->tn_op)); 1332 } 1333 1334 if ((op == ADDASS || op == SUBASS) && lt == PTR) { 1335 lint_assert(is_integer(rt)); 1336 tnode_t *ctn = subt_size_in_bytes(ln->tn_type); 1337 if (rn->tn_type->t_tspec != ctn->tn_type->t_tspec) 1338 rn = convert(NOOP, 0, ctn->tn_type, rn); 1339 rn = build_op(MULT, sys, rn->tn_type, rn, ctn); 1340 if (rn->tn_left->tn_op == CON) 1341 rn = fold(rn); 1342 } 1343 1344 if ((op == ASSIGN || op == RETURN || op == INIT) && 1345 (lt == STRUCT || rt == STRUCT)) { 1346 lint_assert(lt == rt); 1347 lint_assert(ln->tn_type->t_sou == rn->tn_type->t_sou); 1348 if (is_incomplete(ln->tn_type)) { 1349 if (op == RETURN) { 1350 /* cannot return incomplete type */ 1351 error(212); 1352 } else { 1353 /* unknown operand size, op '%s' */ 1354 error(138, op_name(op)); 1355 } 1356 return NULL; 1357 } 1358 } 1359 1360 if (op == SHLASS && hflag && allow_trad && allow_c90 1361 && portable_rank_cmp(lt, rt) < 0) 1362 /* semantics of '%s' change in C90; ... */ 1363 warning(118, "<<="); 1364 1365 if (op != SHLASS && op != SHRASS 1366 && (op == ASSIGN || lt != PTR) 1367 && (lt != rt || (ln->tn_type->t_bitfield && rn->tn_op == CON))) { 1368 rn = convert(op, 0, ln->tn_type, rn); 1369 rt = lt; 1370 } 1371 1372 if (any_query_enabled && rn->tn_op == CVT && rn->tn_cast && 1373 types_compatible(ln->tn_type, rn->tn_type, false, false, NULL) && 1374 is_cast_redundant(rn)) { 1375 /* redundant cast from '%s' to '%s' before assignment */ 1376 query_message(7, 1377 type_name(rn->tn_left->tn_type), type_name(rn->tn_type)); 1378 } 1379 1380 return build_op(op, sys, ln->tn_type, ln, rn); 1381 } 1382 1383 /* 1384 * Create a node for REAL, IMAG 1385 */ 1386 static tnode_t * 1387 build_real_imag(op_t op, bool sys, tnode_t *ln) 1388 { 1389 1390 lint_assert(ln != NULL); 1391 if (ln->tn_op == NAME) { 1392 /* 1393 * This may be too much, but it avoids wrong warnings. 1394 * See d_c99_complex_split.c. 1395 */ 1396 mark_as_used(ln->tn_sym, false, false); 1397 mark_as_set(ln->tn_sym); 1398 } 1399 1400 tspec_t t; 1401 switch (ln->tn_type->t_tspec) { 1402 case LCOMPLEX: 1403 t = LDOUBLE; 1404 break; 1405 case DCOMPLEX: 1406 t = DOUBLE; 1407 break; 1408 case FCOMPLEX: 1409 t = FLOAT; 1410 break; 1411 default: 1412 /* '__%s__' is illegal for type '%s' */ 1413 error(276, op == REAL ? "real" : "imag", 1414 type_name(ln->tn_type)); 1415 return NULL; 1416 } 1417 1418 tnode_t *ntn = build_op(op, sys, gettyp(t), ln, NULL); 1419 ntn->tn_lvalue = true; 1420 return ntn; 1421 } 1422 1423 static bool 1424 is_confusing_precedence(op_t op, op_t lop, bool lparen, op_t rop, bool rparen) 1425 { 1426 1427 if (op == SHL || op == SHR) { 1428 if (!lparen && (lop == PLUS || lop == MINUS)) 1429 return true; 1430 if (!rparen && (rop == PLUS || rop == MINUS)) 1431 return true; 1432 return false; 1433 } 1434 1435 if (op == LOGOR) { 1436 if (!lparen && lop == LOGAND) 1437 return true; 1438 if (!rparen && rop == LOGAND) 1439 return true; 1440 return false; 1441 } 1442 1443 lint_assert(op == BITAND || op == BITXOR || op == BITOR); 1444 if (!lparen && lop != op) { 1445 if (lop == PLUS || lop == MINUS) 1446 return true; 1447 if (lop == BITAND || lop == BITXOR) 1448 return true; 1449 } 1450 if (!rparen && rop != op) { 1451 if (rop == PLUS || rop == MINUS) 1452 return true; 1453 if (rop == BITAND || rop == BITXOR) 1454 return true; 1455 } 1456 return false; 1457 } 1458 1459 /* 1460 * Print a warning if the given node has operands which should be 1461 * parenthesized. 1462 * 1463 * XXX Does not work if an operand is a constant expression. Constant 1464 * expressions are already folded. 1465 */ 1466 static void 1467 check_precedence_confusion(tnode_t *tn) 1468 { 1469 tnode_t *ln, *rn; 1470 1471 if (!hflag) 1472 return; 1473 1474 debug_node(tn); 1475 1476 lint_assert(is_binary(tn)); 1477 for (ln = tn->tn_left; ln->tn_op == CVT; ln = ln->tn_left) 1478 continue; 1479 for (rn = tn->tn_right; rn->tn_op == CVT; rn = rn->tn_left) 1480 continue; 1481 1482 if (is_confusing_precedence(tn->tn_op, 1483 ln->tn_op, ln->tn_parenthesized, 1484 rn->tn_op, rn->tn_parenthesized)) { 1485 /* precedence confusion possible: parenthesize! */ 1486 warning(169); 1487 } 1488 } 1489 1490 /* 1491 * Fold constant nodes, as much as is needed for comparing the value with 0. 1492 */ 1493 static tnode_t * 1494 fold_bool(tnode_t *tn) 1495 { 1496 1497 val_t *v = xcalloc(1, sizeof(*v)); 1498 v->v_tspec = tn->tn_type->t_tspec; 1499 lint_assert(v->v_tspec == INT || (Tflag && v->v_tspec == BOOL)); 1500 1501 lint_assert(has_operands(tn)); 1502 bool l = constant_is_nonzero(tn->tn_left); 1503 bool r = is_binary(tn) && constant_is_nonzero(tn->tn_right); 1504 1505 switch (tn->tn_op) { 1506 case NOT: 1507 if (hflag && !suppress_constcond) 1508 /* constant operand to '!' */ 1509 warning(239); 1510 v->u.integer = !l ? 1 : 0; 1511 break; 1512 case LOGAND: 1513 v->u.integer = l && r ? 1 : 0; 1514 break; 1515 case LOGOR: 1516 v->u.integer = l || r ? 1 : 0; 1517 break; 1518 default: 1519 lint_assert(/*CONSTCOND*/false); 1520 } 1521 1522 return build_constant(tn->tn_type, v); 1523 } 1524 1525 static long double 1526 floating_error_value(tspec_t t, long double lv) 1527 { 1528 if (t == FLOAT) 1529 return lv < 0 ? -FLT_MAX : FLT_MAX; 1530 if (t == DOUBLE) 1531 return lv < 0 ? -DBL_MAX : DBL_MAX; 1532 /* 1533 * When NetBSD is cross-built in MKLINT=yes mode on x86_64 for 1534 * sparc64, tools/lint checks this code while building usr.bin/xlint. 1535 * In that situation, lint uses the preprocessor for sparc64, in which 1536 * the type 'long double' is IEEE-754-binary128, affecting the macro 1537 * LDBL_MAX below. The type 'long double', as well as the strtold 1538 * implementation, comes from the host platform x86_64 though, where 1539 * 'long double' consumes 128 bits as well but only uses 80 of them. 1540 * The exponent range of the two 'long double' types is the same, but 1541 * the maximum finite value differs due to the extended precision on 1542 * sparc64. 1543 * 1544 * To properly handle the data types of the target platform, lint 1545 * would have to implement the floating-point types in a 1546 * platform-independent way, which is not worth the effort, given how 1547 * few programs practically use 'long double'. 1548 */ 1549 /* LINTED 248: floating-point constant out of range */ 1550 long double max = LDBL_MAX; 1551 return lv < 0 ? -max : max; 1552 } 1553 1554 static bool 1555 is_floating_overflow(tspec_t t, long double val) 1556 { 1557 if (fpe != 0 || isfinite(val) == 0) 1558 return true; 1559 if (t == FLOAT && (val > FLT_MAX || val < -FLT_MAX)) 1560 return true; 1561 if (t == DOUBLE && (val > DBL_MAX || val < -DBL_MAX)) 1562 return true; 1563 return false; 1564 } 1565 1566 /* 1567 * Fold constant nodes having operands with floating point type. 1568 */ 1569 static tnode_t * 1570 fold_float(tnode_t *tn) 1571 { 1572 1573 fpe = 0; 1574 1575 tspec_t t = tn->tn_type->t_tspec; 1576 1577 val_t *v = xcalloc(1, sizeof(*v)); 1578 v->v_tspec = t; 1579 1580 lint_assert(is_floating(t)); 1581 lint_assert(has_operands(tn)); 1582 lint_assert(t == tn->tn_left->tn_type->t_tspec); 1583 lint_assert(!is_binary(tn) || t == tn->tn_right->tn_type->t_tspec); 1584 1585 long double lv = tn->tn_left->tn_val.u.floating; 1586 long double rv = is_binary(tn) ? tn->tn_right->tn_val.u.floating : 0.0; 1587 1588 switch (tn->tn_op) { 1589 case UPLUS: 1590 v->u.floating = lv; 1591 break; 1592 case UMINUS: 1593 v->u.floating = -lv; 1594 break; 1595 case MULT: 1596 v->u.floating = lv * rv; 1597 break; 1598 case DIV: 1599 if (rv == 0.0) { 1600 /* division by 0 */ 1601 error(139); 1602 v->u.floating = floating_error_value(t, lv); 1603 } else { 1604 v->u.floating = lv / rv; 1605 } 1606 break; 1607 case PLUS: 1608 v->u.floating = lv + rv; 1609 break; 1610 case MINUS: 1611 v->u.floating = lv - rv; 1612 break; 1613 case LT: 1614 v->u.integer = lv < rv ? 1 : 0; 1615 break; 1616 case LE: 1617 v->u.integer = lv <= rv ? 1 : 0; 1618 break; 1619 case GE: 1620 v->u.integer = lv >= rv ? 1 : 0; 1621 break; 1622 case GT: 1623 v->u.integer = lv > rv ? 1 : 0; 1624 break; 1625 case EQ: 1626 v->u.integer = lv == rv ? 1 : 0; 1627 break; 1628 case NE: 1629 v->u.integer = lv != rv ? 1 : 0; 1630 break; 1631 default: 1632 lint_assert(/*CONSTCOND*/false); 1633 } 1634 1635 // XXX: Must not access u.floating after setting u.integer. 1636 lint_assert(fpe != 0 || isnan(v->u.floating) == 0); 1637 if (is_complex(v->v_tspec)) { 1638 /* 1639 * Don't warn, as lint doesn't model the imaginary part of 1640 * complex numbers. 1641 */ 1642 fpe = 0; 1643 } else if (is_floating_overflow(t, v->u.floating)) { 1644 /* operator '%s' produces floating point overflow */ 1645 warning(142, op_name(tn->tn_op)); 1646 v->u.floating = floating_error_value(t, v->u.floating); 1647 fpe = 0; 1648 } 1649 1650 return build_constant(tn->tn_type, v); 1651 } 1652 1653 static void 1654 use(const tnode_t *tn) 1655 { 1656 if (tn == NULL) 1657 return; 1658 switch (tn->tn_op) { 1659 case NAME: 1660 mark_as_used(tn->tn_sym, false /* XXX */, false /* XXX */); 1661 break; 1662 case CON: 1663 case STRING: 1664 break; 1665 default: 1666 lint_assert(has_operands(tn)); 1667 use(tn->tn_left); 1668 if (is_binary(tn) || tn->tn_op == PUSH) 1669 use(tn->tn_right); 1670 } 1671 } 1672 1673 /* 1674 * Create a tree node for a binary operator and its two operands. Also called 1675 * for unary operators; in that case rn is NULL. 1676 * 1677 * Function calls, sizeof and casts are handled elsewhere. 1678 */ 1679 tnode_t * 1680 build_binary(tnode_t *ln, op_t op, bool sys, tnode_t *rn) 1681 { 1682 const mod_t *mp = &modtab[op]; 1683 1684 /* If there was an error in one of the operands, return. */ 1685 if (ln == NULL || (mp->m_binary && rn == NULL)) 1686 return NULL; 1687 1688 /* 1689 * Apply class conversions to the left operand, but only if its 1690 * value is needed or compared with zero. 1691 */ 1692 if (mp->m_value_context || mp->m_compares_with_zero) 1693 ln = cconv(ln); 1694 /* 1695 * The right operand is almost always in a test or value context, 1696 * except if it is a struct or union member. 1697 */ 1698 if (mp->m_binary && op != ARROW && op != POINT) 1699 rn = cconv(rn); 1700 1701 /* 1702 * Print some warnings for comparisons of unsigned values with 1703 * constants lower than or equal to null. This must be done 1704 * before promote() because otherwise unsigned char and unsigned 1705 * short would be promoted to int. Types are also tested to be 1706 * CHAR, which would also become int. 1707 */ 1708 if (mp->m_comparison) 1709 check_integer_comparison(op, ln, rn); 1710 1711 if (mp->m_value_context || mp->m_compares_with_zero) 1712 ln = promote(op, false, ln); 1713 if (mp->m_binary && op != ARROW && op != POINT && 1714 op != ASSIGN && op != RETURN && op != INIT) { 1715 rn = promote(op, false, rn); 1716 } 1717 1718 /* 1719 * If the result of the operation is different for signed or 1720 * unsigned operands and one of the operands is signed only in 1721 * C90, print a warning. 1722 */ 1723 if (mp->m_warn_if_left_unsigned_in_c90 && 1724 ln->tn_op == CON && ln->tn_val.v_unsigned_since_c90) { 1725 /* C90 treats constant as unsigned, op '%s' */ 1726 warning(218, op_name(op)); 1727 ln->tn_val.v_unsigned_since_c90 = false; 1728 } 1729 if (mp->m_warn_if_right_unsigned_in_c90 && 1730 rn->tn_op == CON && rn->tn_val.v_unsigned_since_c90) { 1731 /* C90 treats constant as unsigned, op '%s' */ 1732 warning(218, op_name(op)); 1733 rn->tn_val.v_unsigned_since_c90 = false; 1734 } 1735 1736 /* Make sure both operands are of the same type */ 1737 if (mp->m_balance_operands || (!allow_c90 && (op == SHL || op == SHR))) 1738 balance(op, &ln, &rn); 1739 1740 /* 1741 * Check types for compatibility with the operation and mutual 1742 * compatibility. Return if there are serious problems. 1743 */ 1744 if (!typeok(op, 0, ln, rn)) 1745 return NULL; 1746 1747 /* And now create the node. */ 1748 tnode_t *ntn; 1749 switch (op) { 1750 case POINT: 1751 case ARROW: 1752 ntn = build_struct_access(op, sys, ln, rn); 1753 break; 1754 case INCAFT: 1755 case DECAFT: 1756 case INCBEF: 1757 case DECBEF: 1758 ntn = build_prepost_incdec(op, sys, ln); 1759 break; 1760 case ADDR: 1761 ntn = build_address(sys, ln, false); 1762 break; 1763 case INDIR: 1764 ntn = build_op(INDIR, sys, ln->tn_type->t_subt, ln, NULL); 1765 break; 1766 case PLUS: 1767 case MINUS: 1768 ntn = build_plus_minus(op, sys, ln, rn); 1769 break; 1770 case SHL: 1771 case SHR: 1772 ntn = build_bit_shift(op, sys, ln, rn); 1773 break; 1774 case COLON: 1775 ntn = build_colon(sys, ln, rn); 1776 break; 1777 case ASSIGN: 1778 case MULASS: 1779 case DIVASS: 1780 case MODASS: 1781 case ADDASS: 1782 case SUBASS: 1783 case SHLASS: 1784 case SHRASS: 1785 case ANDASS: 1786 case XORASS: 1787 case ORASS: 1788 case RETURN: 1789 case INIT: 1790 ntn = build_assignment(op, sys, ln, rn); 1791 break; 1792 case COMMA: 1793 if (any_query_enabled) { 1794 /* comma operator with types '%s' and '%s' */ 1795 query_message(12, 1796 type_name(ln->tn_type), type_name(rn->tn_type)); 1797 } 1798 /* FALLTHROUGH */ 1799 case QUEST: 1800 ntn = build_op(op, sys, rn->tn_type, ln, rn); 1801 break; 1802 case REAL: 1803 case IMAG: 1804 ntn = build_real_imag(op, sys, ln); 1805 break; 1806 default: 1807 lint_assert(mp->m_binary == (rn != NULL)); 1808 type_t *rettp = mp->m_returns_bool 1809 ? gettyp(Tflag ? BOOL : INT) : ln->tn_type; 1810 ntn = build_op(op, sys, rettp, ln, rn); 1811 break; 1812 } 1813 1814 /* Return if an error occurred. */ 1815 if (ntn == NULL) 1816 return NULL; 1817 1818 /* Print a warning if precedence confusion is possible */ 1819 if (mp->m_possible_precedence_confusion) 1820 check_precedence_confusion(ntn); 1821 1822 /* 1823 * Print a warning if one of the operands is in a context where 1824 * it is compared with zero and if this operand is a constant. 1825 */ 1826 if (hflag && !suppress_constcond && 1827 mp->m_compares_with_zero && 1828 (ln->tn_op == CON || 1829 ((mp->m_binary && op != QUEST) && rn->tn_op == CON)) && 1830 /* XXX: rn->tn_system_dependent should be checked as well */ 1831 !ln->tn_system_dependent) { 1832 /* constant in conditional context */ 1833 warning(161); 1834 } 1835 1836 /* Fold if the operator requires it */ 1837 if (mp->m_fold_constant_operands) { 1838 if (ln->tn_op == CON && (!mp->m_binary || rn->tn_op == CON)) { 1839 if (mp->m_compares_with_zero) { 1840 ntn = fold_bool(ntn); 1841 } else if (is_floating(ntn->tn_type->t_tspec)) { 1842 ntn = fold_float(ntn); 1843 } else { 1844 ntn = fold(ntn); 1845 } 1846 } else if (op == QUEST && ln->tn_op == CON) { 1847 lint_assert(has_operands(rn)); 1848 use(ln->tn_val.u.integer != 0 1849 ? rn->tn_right : rn->tn_left); 1850 ntn = ln->tn_val.u.integer != 0 1851 ? rn->tn_left : rn->tn_right; 1852 } 1853 } 1854 1855 return ntn; 1856 } 1857 1858 tnode_t * 1859 build_unary(op_t op, bool sys, tnode_t *tn) 1860 { 1861 return build_binary(tn, op, sys, NULL); 1862 } 1863 1864 static bool 1865 are_members_compatible(const sym_t *a, const sym_t *b) 1866 { 1867 if (a->u.s_member.sm_offset_in_bits != b->u.s_member.sm_offset_in_bits) 1868 return false; 1869 1870 const type_t *atp = a->s_type; 1871 const type_t *btp = b->s_type; 1872 bool w = false; 1873 if (!types_compatible(atp, btp, false, false, &w) && !w) 1874 return false; 1875 if (a->s_bitfield != b->s_bitfield) 1876 return false; 1877 if (a->s_bitfield) { 1878 if (atp->t_bit_field_width != btp->t_bit_field_width) 1879 return false; 1880 if (atp->t_bit_field_offset != btp->t_bit_field_offset) 1881 return false; 1882 } 1883 return true; 1884 } 1885 1886 /* 1887 * Return whether all struct/union members with the same name have the same 1888 * type and offset. 1889 */ 1890 static bool 1891 all_members_compatible(const sym_t *msym) 1892 { 1893 for (const sym_t *csym = msym; 1894 csym != NULL; csym = csym->s_symtab_next) { 1895 if (!is_member(csym)) 1896 continue; 1897 if (strcmp(msym->s_name, csym->s_name) != 0) 1898 continue; 1899 1900 for (const sym_t *sym = csym->s_symtab_next; 1901 sym != NULL; sym = sym->s_symtab_next) { 1902 if (is_member(sym) 1903 && strcmp(csym->s_name, sym->s_name) == 0 1904 && !are_members_compatible(csym, sym)) 1905 return false; 1906 } 1907 } 1908 return true; 1909 } 1910 1911 sym_t * 1912 find_member(const struct_or_union *sou, const char *name) 1913 { 1914 for (sym_t *mem = sou->sou_first_member; 1915 mem != NULL; mem = mem->s_next) { 1916 lint_assert(is_member(mem)); 1917 lint_assert(mem->u.s_member.sm_containing_type == sou); 1918 if (strcmp(mem->s_name, name) == 0) 1919 return mem; 1920 } 1921 1922 for (sym_t *mem = sou->sou_first_member; 1923 mem != NULL; mem = mem->s_next) { 1924 if (is_struct_or_union(mem->s_type->t_tspec) 1925 && mem->s_name == unnamed) { 1926 sym_t *nested_mem = 1927 find_member(mem->s_type->t_sou, name); 1928 if (nested_mem != NULL) 1929 return nested_mem; 1930 } 1931 } 1932 return NULL; 1933 } 1934 1935 /* 1936 * Remove the member if it was unknown until now, which means 1937 * that no defined struct or union has a member with the same name. 1938 */ 1939 static void 1940 remove_unknown_member(tnode_t *tn, sym_t *msym) 1941 { 1942 /* type '%s' does not have member '%s' */ 1943 error(101, type_name(tn->tn_type), msym->s_name); 1944 rmsym(msym); 1945 msym->s_kind = FMEMBER; 1946 msym->s_scl = STRUCT_MEMBER; 1947 1948 struct_or_union *sou = expr_zero_alloc(sizeof(*sou), 1949 "struct_or_union"); 1950 sou->sou_tag = expr_zero_alloc(sizeof(*sou->sou_tag), "sym"); 1951 sou->sou_tag->s_name = unnamed; 1952 1953 msym->u.s_member.sm_containing_type = sou; 1954 /* 1955 * The member sm_offset_in_bits is not needed here since this 1956 * symbol can only be used for error reporting. 1957 */ 1958 } 1959 1960 /* 1961 * Returns a symbol which has the same name as 'msym' and is a member of the 1962 * struct or union specified by 'tn'. 1963 */ 1964 static sym_t * 1965 struct_or_union_member(tnode_t *tn, op_t op, sym_t *msym) 1966 { 1967 1968 /* Determine the tag type of which msym is expected to be a member. */ 1969 const type_t *tp = NULL; 1970 if (op == POINT && is_struct_or_union(tn->tn_type->t_tspec)) 1971 tp = tn->tn_type; 1972 if (op == ARROW && tn->tn_type->t_tspec == PTR 1973 && is_struct_or_union(tn->tn_type->t_subt->t_tspec)) 1974 tp = tn->tn_type->t_subt; 1975 struct_or_union *sou = tp != NULL ? tp->t_sou : NULL; 1976 1977 if (sou != NULL) { 1978 sym_t *nested_mem = find_member(sou, msym->s_name); 1979 if (nested_mem != NULL) 1980 return nested_mem; 1981 } 1982 1983 if (msym->s_scl == NO_SCL) { 1984 remove_unknown_member(tn, msym); 1985 return msym; 1986 } 1987 1988 bool eq = all_members_compatible(msym); 1989 1990 /* 1991 * Now handle the case in which the left operand refers really 1992 * to a struct/union, but the right operand is not member of it. 1993 */ 1994 if (sou != NULL) { 1995 if (eq && !allow_c90) { 1996 /* illegal use of member '%s' */ 1997 warning(102, msym->s_name); 1998 } else { 1999 /* illegal use of member '%s' */ 2000 error(102, msym->s_name); 2001 } 2002 return msym; 2003 } 2004 2005 /* 2006 * Now the left operand of ARROW does not point to a struct/union 2007 * or the left operand of POINT is no struct/union. 2008 */ 2009 if (eq) { 2010 if (op == POINT) { 2011 if (!allow_c90) { 2012 /* left operand of '.' must be struct ... */ 2013 warning(103, type_name(tn->tn_type)); 2014 } else { 2015 /* left operand of '.' must be struct ... */ 2016 error(103, type_name(tn->tn_type)); 2017 } 2018 } else { 2019 if (!allow_c90 && tn->tn_type->t_tspec == PTR) { 2020 /* left operand of '->' must be pointer ... */ 2021 warning(104, type_name(tn->tn_type)); 2022 } else { 2023 /* left operand of '->' must be pointer ... */ 2024 error(104, type_name(tn->tn_type)); 2025 } 2026 } 2027 } else { 2028 if (!allow_c90) { 2029 /* non-unique member requires struct/union %s */ 2030 error(105, op == POINT ? "object" : "pointer"); 2031 } else { 2032 /* unacceptable operand of '%s' */ 2033 error(111, op_name(op)); 2034 } 2035 } 2036 2037 return msym; 2038 } 2039 2040 tnode_t * 2041 build_member_access(tnode_t *ln, op_t op, bool sys, sbuf_t *member) 2042 { 2043 sym_t *msym; 2044 2045 if (ln == NULL) 2046 return NULL; 2047 2048 if (op == ARROW) { 2049 /* must do this before struct_or_union_member is called */ 2050 ln = cconv(ln); 2051 } 2052 msym = struct_or_union_member(ln, op, getsym(member)); 2053 return build_binary(ln, op, sys, build_name(msym, false)); 2054 } 2055 2056 /* 2057 * Perform class conversions. 2058 * 2059 * Arrays of type T are converted into pointers to type T. 2060 * Functions are converted to pointers to functions. 2061 * Lvalues are converted to rvalues. 2062 * 2063 * C99 6.3 "Conversions" 2064 * C99 6.3.2 "Other operands" 2065 * C99 6.3.2.1 "Lvalues, arrays, and function designators" 2066 */ 2067 tnode_t * 2068 cconv(tnode_t *tn) 2069 { 2070 /* 2071 * Array-lvalue (array of type T) is converted into rvalue 2072 * (pointer to type T) 2073 */ 2074 if (tn->tn_type->t_tspec == ARRAY) { 2075 if (!tn->tn_lvalue) { 2076 /* XXX print correct operator */ 2077 /* %soperand of '%s' must be lvalue */ 2078 gnuism(114, "", op_name(ADDR)); 2079 } 2080 tn = build_op(ADDR, tn->tn_sys, 2081 expr_derive_type(tn->tn_type->t_subt, PTR), tn, NULL); 2082 } 2083 2084 /* 2085 * Expression of type function (function with return value of type T) 2086 * in rvalue-expression (pointer to function with return value 2087 * of type T) 2088 */ 2089 if (tn->tn_type->t_tspec == FUNC) 2090 tn = build_address(tn->tn_sys, tn, true); 2091 2092 /* lvalue to rvalue */ 2093 if (tn->tn_lvalue) { 2094 type_t *tp = expr_dup_type(tn->tn_type); 2095 /* C99 6.3.2.1p2 sentence 2 says to remove the qualifiers. */ 2096 tp->t_const = tp->t_volatile = false; 2097 tn = build_op(LOAD, tn->tn_sys, tp, tn, NULL); 2098 } 2099 2100 return tn; 2101 } 2102 2103 const tnode_t * 2104 before_conversion(const tnode_t *tn) 2105 { 2106 while (tn->tn_op == CVT && !tn->tn_cast) 2107 tn = tn->tn_left; 2108 return tn; 2109 } 2110 2111 /* 2112 * Most errors required by C90 are reported in struct_or_union_member(). 2113 * Here we only check for totally wrong things. 2114 */ 2115 static bool 2116 typeok_point(const tnode_t *ln, const type_t *ltp, tspec_t lt) 2117 { 2118 if (is_struct_or_union(lt)) 2119 return true; 2120 2121 if (lt == FUNC || lt == VOID || ltp->t_bitfield) 2122 goto wrong; 2123 2124 /* 2125 * Some C dialects from before C90 tolerated any lvalue on the 2126 * left-hand side of the '.' operator, allowing things like 2127 * char st[100]; st.st_mtime, assuming that the member 'st_mtime' 2128 * only occurred in a single struct; see typeok_arrow. 2129 */ 2130 if (ln->tn_lvalue) 2131 return true; 2132 2133 wrong: 2134 /* With allow_c90 we already got an error */ 2135 if (!allow_c90) 2136 /* unacceptable operand of '%s' */ 2137 error(111, op_name(POINT)); 2138 2139 return false; 2140 } 2141 2142 static bool 2143 typeok_arrow(tspec_t lt) 2144 { 2145 /* 2146 * C1978 Appendix A 14.1 says: <quote>In fact, any lvalue is allowed 2147 * before '.', and that lvalue is then assumed to have the form of 2148 * the structure of which the name of the right is a member. [...] 2149 * Such constructions are non-portable.</quote> 2150 */ 2151 if (lt == PTR || (!allow_c90 && is_integer(lt))) 2152 return true; 2153 2154 /* With allow_c90 we already got an error */ 2155 if (!allow_c90) 2156 /* unacceptable operand of '%s' */ 2157 error(111, op_name(ARROW)); 2158 return false; 2159 } 2160 2161 static bool 2162 typeok_incdec(op_t op, const tnode_t *tn, const type_t *tp) 2163 { 2164 /* operand has scalar type (checked in typeok) */ 2165 if (!tn->tn_lvalue) { 2166 if (tn->tn_op == CVT && tn->tn_cast && 2167 tn->tn_left->tn_op == LOAD) { 2168 /* a cast does not yield an lvalue */ 2169 error(163); 2170 } 2171 /* %soperand of '%s' must be lvalue */ 2172 error(114, "", op_name(op)); 2173 return false; 2174 } 2175 if (tp->t_const && allow_c90) { 2176 /* %soperand of '%s' must be modifiable lvalue */ 2177 warning(115, "", op_name(op)); 2178 } 2179 return true; 2180 } 2181 2182 static bool 2183 typeok_address(op_t op, const tnode_t *tn, const type_t *tp, tspec_t t) 2184 { 2185 if (t == ARRAY || t == FUNC) { 2186 /* ok, a warning comes later (in build_address()) */ 2187 } else if (!tn->tn_lvalue) { 2188 if (tn->tn_op == CVT && tn->tn_cast && 2189 tn->tn_left->tn_op == LOAD) { 2190 /* a cast does not yield an lvalue */ 2191 error(163); 2192 } 2193 /* %soperand of '%s' must be lvalue */ 2194 error(114, "", op_name(op)); 2195 return false; 2196 } else if (is_scalar(t)) { 2197 if (tp->t_bitfield) { 2198 /* cannot take address of bit-field */ 2199 error(112); 2200 return false; 2201 } 2202 } else if (t != STRUCT && t != UNION) { 2203 /* unacceptable operand of '%s' */ 2204 error(111, op_name(op)); 2205 return false; 2206 } 2207 if (tn->tn_op == NAME && tn->tn_sym->s_register) { 2208 /* cannot take address of register '%s' */ 2209 error(113, tn->tn_sym->s_name); 2210 return false; 2211 } 2212 return true; 2213 } 2214 2215 static bool 2216 typeok_indir(const type_t *tp, tspec_t t) 2217 { 2218 2219 if (t != PTR) { 2220 /* cannot dereference non-pointer type '%s' */ 2221 error(96, type_name(tp)); 2222 return false; 2223 } 2224 return true; 2225 } 2226 2227 static void 2228 warn_incompatible_types(op_t op, 2229 const type_t *ltp, tspec_t lt, 2230 const type_t *rtp, tspec_t rt) 2231 { 2232 bool binary = modtab[op].m_binary; 2233 2234 if (lt == VOID || (binary && rt == VOID)) { 2235 /* void type illegal in expression */ 2236 error(109); 2237 } else if (op == ASSIGN) { 2238 /* cannot assign to '%s' from '%s' */ 2239 error(171, type_name(ltp), type_name(rtp)); 2240 } else if (binary) { 2241 /* operands of '%s' have incompatible types '%s' and '%s' */ 2242 error(107, op_name(op), type_name(ltp), type_name(rtp)); 2243 } else { 2244 lint_assert(rt == NO_TSPEC); 2245 /* operand of '%s' has invalid type '%s' */ 2246 error(108, op_name(op), type_name(ltp)); 2247 } 2248 } 2249 2250 static bool 2251 typeok_plus(op_t op, 2252 const type_t *ltp, tspec_t lt, 2253 const type_t *rtp, tspec_t rt) 2254 { 2255 /* operands have scalar types (checked in typeok) */ 2256 if ((lt == PTR && !is_integer(rt)) || (rt == PTR && !is_integer(lt))) { 2257 warn_incompatible_types(op, ltp, lt, rtp, rt); 2258 return false; 2259 } 2260 return true; 2261 } 2262 2263 static bool 2264 typeok_minus(op_t op, 2265 const type_t *ltp, tspec_t lt, 2266 const type_t *rtp, tspec_t rt) 2267 { 2268 /* operands have scalar types (checked in typeok) */ 2269 if ((lt == PTR && rt != PTR && !is_integer(rt)) || 2270 (lt != PTR && rt == PTR)) { 2271 warn_incompatible_types(op, ltp, lt, rtp, rt); 2272 return false; 2273 } 2274 if (lt == PTR && rt == PTR && 2275 !types_compatible(ltp->t_subt, rtp->t_subt, true, false, NULL)) { 2276 /* illegal pointer subtraction */ 2277 error(116); 2278 } 2279 return true; 2280 } 2281 2282 static void 2283 typeok_shr(op_t op, 2284 const tnode_t *ln, tspec_t lt, 2285 const tnode_t *rn, tspec_t rt) 2286 { 2287 tspec_t olt = before_conversion(ln)->tn_type->t_tspec; 2288 tspec_t ort = before_conversion(rn)->tn_type->t_tspec; 2289 2290 /* operands have integer types (checked in typeok) */ 2291 if (pflag && !is_uinteger(olt)) { 2292 integer_constraints lc = ic_expr(ln); 2293 if (!ic_maybe_signed(ln->tn_type, &lc)) 2294 return; 2295 2296 /* 2297 * The left operand is signed. This means that 2298 * the operation is (possibly) nonportable. 2299 */ 2300 if (ln->tn_op != CON) { 2301 /* bitwise '%s' on signed value possibly nonportable */ 2302 warning(117, op_name(op)); 2303 } else if (ln->tn_val.u.integer < 0) { 2304 /* bitwise '%s' on signed value nonportable */ 2305 warning(120, op_name(op)); 2306 } 2307 } else if (allow_trad && allow_c90 && 2308 !is_uinteger(olt) && is_uinteger(ort)) { 2309 /* The left operand would become unsigned in traditional C. */ 2310 if (hflag && (ln->tn_op != CON || ln->tn_val.u.integer < 0)) { 2311 /* semantics of '%s' change in C90; use ... */ 2312 warning(118, op_name(op)); 2313 } 2314 } else if (allow_trad && allow_c90 && 2315 !is_uinteger(olt) && !is_uinteger(ort) && 2316 portable_rank_cmp(lt, rt) < 0) { 2317 /* 2318 * In traditional C, the left operand would be extended 2319 * (possibly sign-extended) and then shifted. 2320 */ 2321 if (hflag && (ln->tn_op != CON || ln->tn_val.u.integer < 0)) { 2322 /* semantics of '%s' change in C90; use ... */ 2323 warning(118, op_name(op)); 2324 } 2325 } 2326 } 2327 2328 static void 2329 typeok_shl(op_t op, tspec_t lt, tspec_t rt) 2330 { 2331 /* 2332 * C90 does not perform balancing for shift operations, 2333 * but traditional C does. If the width of the right operand 2334 * is greater than the width of the left operand, then in 2335 * traditional C the left operand would be extended to the 2336 * width of the right operand. For SHL this may result in 2337 * different results. 2338 */ 2339 if (portable_rank_cmp(lt, rt) < 0) { 2340 /* 2341 * XXX If both operands are constant, make sure 2342 * that there is really a difference between 2343 * C90 and traditional C. 2344 */ 2345 if (hflag && allow_trad && allow_c90) 2346 /* semantics of '%s' change in C90; use ... */ 2347 warning(118, op_name(op)); 2348 } 2349 } 2350 2351 static void 2352 typeok_shift(const type_t *ltp, tspec_t lt, const tnode_t *rn, tspec_t rt) 2353 { 2354 if (rn->tn_op != CON) 2355 return; 2356 2357 if (!is_uinteger(rt) && rn->tn_val.u.integer < 0) { 2358 /* negative shift */ 2359 warning(121); 2360 } else if ((uint64_t)rn->tn_val.u.integer == size_in_bits(lt)) { 2361 /* shift amount %u equals bit-size of '%s' */ 2362 warning(267, (unsigned)rn->tn_val.u.integer, type_name(ltp)); 2363 } else if ((uint64_t)rn->tn_val.u.integer > size_in_bits(lt)) { 2364 /* shift amount %llu is greater than bit-size %llu of '%s' */ 2365 warning(122, (unsigned long long)rn->tn_val.u.integer, 2366 (unsigned long long)size_in_bits(lt), 2367 tspec_name(lt)); 2368 } 2369 } 2370 2371 static bool 2372 is_typeok_eq(const tnode_t *ln, tspec_t lt, const tnode_t *rn, tspec_t rt) 2373 { 2374 if (lt == PTR && is_null_pointer(rn)) 2375 return true; 2376 if (rt == PTR && is_null_pointer(ln)) 2377 return true; 2378 return false; 2379 } 2380 2381 /* 2382 * Called if incompatible pointer types are detected. 2383 * Print an appropriate warning. 2384 */ 2385 static void 2386 warn_incompatible_pointers(op_t op, const type_t *ltp, const type_t *rtp) 2387 { 2388 lint_assert(ltp->t_tspec == PTR); 2389 lint_assert(rtp->t_tspec == PTR); 2390 2391 tspec_t lt = ltp->t_subt->t_tspec; 2392 tspec_t rt = rtp->t_subt->t_tspec; 2393 2394 if (is_struct_or_union(lt) && is_struct_or_union(rt)) { 2395 if (op == RETURN) { 2396 /* illegal structure pointer combination */ 2397 warning(244); 2398 } else { 2399 /* incompatible structure pointers: '%s' '%s' '%s' */ 2400 warning(245, type_name(ltp), 2401 op_name(op), type_name(rtp)); 2402 } 2403 } else { 2404 if (op == RETURN) { 2405 /* illegal combination of '%s' and '%s' */ 2406 warning(184, type_name(ltp), type_name(rtp)); 2407 } else { 2408 /* illegal combination of '%s' and '%s', op '%s' */ 2409 warning(124, 2410 type_name(ltp), type_name(rtp), op_name(op)); 2411 } 2412 } 2413 } 2414 2415 static void 2416 check_pointer_comparison(op_t op, const tnode_t *ln, const tnode_t *rn) 2417 { 2418 type_t *ltp = ln->tn_type, *rtp = rn->tn_type; 2419 tspec_t lst = ltp->t_subt->t_tspec, rst = rtp->t_subt->t_tspec; 2420 2421 if (lst == VOID || rst == VOID) { 2422 /* TODO: C99 behaves like C90 here. */ 2423 if ((!allow_trad && !allow_c99) && 2424 (lst == FUNC || rst == FUNC)) { 2425 /* (void *)0 is already handled in typeok() */ 2426 const char *lsts, *rsts; 2427 *(lst == FUNC ? &lsts : &rsts) = "function pointer"; 2428 *(lst == VOID ? &lsts : &rsts) = "'void *'"; 2429 /* C90 or later forbid comparison of %s with %s */ 2430 warning(274, lsts, rsts); 2431 } 2432 return; 2433 } 2434 2435 if (!types_compatible(ltp->t_subt, rtp->t_subt, true, false, NULL)) { 2436 warn_incompatible_pointers(op, ltp, rtp); 2437 return; 2438 } 2439 2440 if (lst == FUNC && rst == FUNC) { 2441 /* TODO: C99 behaves like C90 here, see C99 6.5.8p2. */ 2442 if ((!allow_trad && !allow_c99) && op != EQ && op != NE) 2443 /* pointers to functions can only be compared ... */ 2444 warning(125); 2445 } 2446 } 2447 2448 static bool 2449 typeok_compare(op_t op, 2450 const tnode_t *ln, const type_t *ltp, tspec_t lt, 2451 const tnode_t *rn, const type_t *rtp, tspec_t rt) 2452 { 2453 if (lt == PTR && rt == PTR) { 2454 check_pointer_comparison(op, ln, rn); 2455 return true; 2456 } 2457 2458 if (lt != PTR && rt != PTR) 2459 return true; 2460 2461 if (!is_integer(lt) && !is_integer(rt)) { 2462 warn_incompatible_types(op, ltp, lt, rtp, rt); 2463 return false; 2464 } 2465 2466 const char *lx = lt == PTR ? "pointer" : "integer"; 2467 const char *rx = rt == PTR ? "pointer" : "integer"; 2468 /* illegal combination of %s '%s' and %s '%s', op '%s' */ 2469 warning(123, lx, type_name(ltp), rx, type_name(rtp), op_name(op)); 2470 return true; 2471 } 2472 2473 static bool 2474 typeok_quest(tspec_t lt, const tnode_t *rn) 2475 { 2476 if (!is_scalar(lt)) { 2477 /* first operand of '?' must have scalar type */ 2478 error(170); 2479 return false; 2480 } 2481 lint_assert(before_conversion(rn)->tn_op == COLON); 2482 return true; 2483 } 2484 2485 static void 2486 typeok_colon_pointer(const type_t *ltp, const type_t *rtp) 2487 { 2488 type_t *lstp = ltp->t_subt; 2489 type_t *rstp = rtp->t_subt; 2490 tspec_t lst = lstp->t_tspec; 2491 tspec_t rst = rstp->t_tspec; 2492 2493 if ((lst == VOID && rst == FUNC) || (lst == FUNC && rst == VOID)) { 2494 /* (void *)0 is handled in typeok_colon */ 2495 /* TODO: C99 behaves like C90 here. */ 2496 if (!allow_trad && !allow_c99) 2497 /* conversion of %s to %s requires a cast, op %s */ 2498 warning(305, "function pointer", "'void *'", 2499 op_name(COLON)); 2500 return; 2501 } 2502 2503 if (pointer_types_are_compatible(lstp, rstp, true)) 2504 return; 2505 if (!types_compatible(lstp, rstp, true, false, NULL)) 2506 warn_incompatible_pointers(COLON, ltp, rtp); 2507 } 2508 2509 static bool 2510 typeok_colon(const tnode_t *ln, const type_t *ltp, tspec_t lt, 2511 const tnode_t *rn, const type_t *rtp, tspec_t rt) 2512 { 2513 2514 if (is_arithmetic(lt) && is_arithmetic(rt)) 2515 return true; 2516 if (lt == BOOL && rt == BOOL) 2517 return true; 2518 2519 if (lt == STRUCT && rt == STRUCT && ltp->t_sou == rtp->t_sou) 2520 return true; 2521 if (lt == UNION && rt == UNION && ltp->t_sou == rtp->t_sou) 2522 return true; 2523 2524 if (lt == PTR && is_null_pointer(rn)) 2525 return true; 2526 if (rt == PTR && is_null_pointer(ln)) 2527 return true; 2528 2529 if ((lt == PTR && is_integer(rt)) || (is_integer(lt) && rt == PTR)) { 2530 const char *lx = lt == PTR ? "pointer" : "integer"; 2531 const char *rx = rt == PTR ? "pointer" : "integer"; 2532 /* illegal combination of %s '%s' and %s '%s', op '%s' */ 2533 warning(123, lx, type_name(ltp), 2534 rx, type_name(rtp), op_name(COLON)); 2535 return true; 2536 } 2537 2538 if (lt == VOID || rt == VOID) { 2539 if (lt != VOID || rt != VOID) 2540 /* incompatible types '%s' and '%s' in conditional */ 2541 warning(126, type_name(ltp), type_name(rtp)); 2542 return true; 2543 } 2544 2545 if (lt == PTR && rt == PTR) { 2546 typeok_colon_pointer(ltp, rtp); 2547 return true; 2548 } 2549 2550 /* incompatible types '%s' and '%s' in conditional */ 2551 error(126, type_name(ltp), type_name(rtp)); 2552 return false; 2553 } 2554 2555 /* 2556 * Returns true if the given structure or union has a constant member 2557 * (maybe recursively). 2558 */ 2559 static bool 2560 has_constant_member(const type_t *tp) 2561 { 2562 lint_assert(is_struct_or_union(tp->t_tspec)); 2563 2564 for (sym_t *m = tp->t_sou->sou_first_member; 2565 m != NULL; m = m->s_next) { 2566 const type_t *mtp = m->s_type; 2567 if (mtp->t_const) 2568 return true; 2569 if (is_struct_or_union(mtp->t_tspec) && 2570 has_constant_member(mtp)) 2571 return true; 2572 } 2573 return false; 2574 } 2575 2576 static bool 2577 typeok_assign(op_t op, const tnode_t *ln, const type_t *ltp, tspec_t lt) 2578 { 2579 if (op == RETURN || op == INIT || op == FARG) 2580 return true; 2581 2582 if (!ln->tn_lvalue) { 2583 if (ln->tn_op == CVT && ln->tn_cast && 2584 ln->tn_left->tn_op == LOAD) { 2585 /* a cast does not yield an lvalue */ 2586 error(163); 2587 } 2588 /* %soperand of '%s' must be lvalue */ 2589 error(114, "left ", op_name(op)); 2590 return false; 2591 } else if (ltp->t_const 2592 || (is_struct_or_union(lt) && has_constant_member(ltp))) { 2593 if (allow_c90) 2594 /* %soperand of '%s' must be modifiable lvalue */ 2595 warning(115, "left ", op_name(op)); 2596 } 2597 return true; 2598 } 2599 2600 /* Check the types using the information from modtab[]. */ 2601 static bool 2602 typeok_scalar(op_t op, const mod_t *mp, 2603 const type_t *ltp, tspec_t lt, 2604 const type_t *rtp, tspec_t rt) 2605 { 2606 if (mp->m_takes_bool && lt == BOOL && rt == BOOL) 2607 return true; 2608 if (mp->m_requires_integer) { 2609 if (!is_integer(lt) || (mp->m_binary && !is_integer(rt))) { 2610 warn_incompatible_types(op, ltp, lt, rtp, rt); 2611 return false; 2612 } 2613 } else if (mp->m_requires_integer_or_complex) { 2614 if ((!is_integer(lt) && !is_complex(lt)) || 2615 (mp->m_binary && (!is_integer(rt) && !is_complex(rt)))) { 2616 warn_incompatible_types(op, ltp, lt, rtp, rt); 2617 return false; 2618 } 2619 } else if (mp->m_requires_scalar) { 2620 if (!is_scalar(lt) || (mp->m_binary && !is_scalar(rt))) { 2621 warn_incompatible_types(op, ltp, lt, rtp, rt); 2622 return false; 2623 } 2624 } else if (mp->m_requires_arith) { 2625 if (!is_arithmetic(lt) || 2626 (mp->m_binary && !is_arithmetic(rt))) { 2627 warn_incompatible_types(op, ltp, lt, rtp, rt); 2628 return false; 2629 } 2630 } 2631 return true; 2632 } 2633 2634 static void 2635 check_assign_void_pointer(op_t op, int arg, 2636 tspec_t lt, tspec_t lst, 2637 tspec_t rt, tspec_t rst) 2638 { 2639 2640 if (!(lt == PTR && rt == PTR && (lst == VOID || rst == VOID))) 2641 return; 2642 /* two pointers, at least one pointer to void */ 2643 2644 /* TODO: C99 behaves like C90 here. */ 2645 if (!((!allow_trad && !allow_c99) && (lst == FUNC || rst == FUNC))) 2646 return; 2647 /* comb. of ptr to func and ptr to void */ 2648 2649 const char *lts, *rts; 2650 *(lst == FUNC ? <s : &rts) = "function pointer"; 2651 *(lst == VOID ? <s : &rts) = "'void *'"; 2652 2653 switch (op) { 2654 case INIT: 2655 case RETURN: 2656 /* conversion of %s to %s requires a cast */ 2657 warning(303, rts, lts); 2658 break; 2659 case FARG: 2660 /* conversion of %s to %s requires a cast, arg #%d */ 2661 warning(304, rts, lts, arg); 2662 break; 2663 default: 2664 /* conversion of %s to %s requires a cast, op %s */ 2665 warning(305, rts, lts, op_name(op)); 2666 break; 2667 } 2668 } 2669 2670 static bool 2671 is_direct_function_call(const tnode_t *tn, const char **out_name) 2672 { 2673 2674 if (!(tn->tn_op == CALL && 2675 tn->tn_left->tn_op == ADDR && 2676 tn->tn_left->tn_left->tn_op == NAME)) 2677 return false; 2678 2679 *out_name = tn->tn_left->tn_left->tn_sym->s_name; 2680 return true; 2681 } 2682 2683 static bool 2684 is_unconst_function(const char *name) 2685 { 2686 2687 return strcmp(name, "memchr") == 0 || 2688 strcmp(name, "strchr") == 0 || 2689 strcmp(name, "strpbrk") == 0 || 2690 strcmp(name, "strrchr") == 0 || 2691 strcmp(name, "strstr") == 0; 2692 } 2693 2694 static bool 2695 is_const_char_pointer(const tnode_t *tn) 2696 { 2697 /* 2698 * For traditional reasons, C99 6.4.5p5 defines that string literals 2699 * have type 'char[]'. They are often implicitly converted to 2700 * 'char *', for example when they are passed as function arguments. 2701 * 2702 * C99 6.4.5p6 further defines that modifying a string that is 2703 * constructed from a string literal invokes undefined behavior. 2704 * 2705 * Out of these reasons, string literals are treated as 'effectively 2706 * const' here. 2707 */ 2708 if (tn->tn_op == CVT && 2709 tn->tn_left->tn_op == ADDR && 2710 tn->tn_left->tn_left->tn_op == STRING) 2711 return true; 2712 2713 const type_t *tp = before_conversion(tn)->tn_type; 2714 return tp->t_tspec == PTR && 2715 tp->t_subt->t_tspec == CHAR && 2716 tp->t_subt->t_const; 2717 } 2718 2719 static bool 2720 is_first_arg_const_char_pointer(const tnode_t *tn) 2721 { 2722 lint_assert(has_operands(tn)); 2723 const tnode_t *an = tn->tn_right; 2724 if (an == NULL) 2725 return false; 2726 2727 while (tn_ck_right(an) != NULL) 2728 an = an->tn_right; 2729 return is_const_char_pointer(an->tn_left); 2730 } 2731 2732 static bool 2733 is_const_pointer(const tnode_t *tn) 2734 { 2735 const type_t *tp = before_conversion(tn)->tn_type; 2736 return tp->t_tspec == PTR && tp->t_subt->t_const; 2737 } 2738 2739 static bool 2740 is_second_arg_const_pointer(const tnode_t *tn) 2741 { 2742 const tnode_t *an = tn_ck_right(tn); 2743 if (an == NULL || tn_ck_right(an) == NULL) 2744 return false; 2745 2746 while (tn_ck_right(an->tn_right) != NULL) 2747 an = an->tn_right; 2748 return is_const_pointer(an->tn_left); 2749 } 2750 2751 static void 2752 check_unconst_function(const type_t *lstp, const tnode_t *rn) 2753 { 2754 const char *function_name; 2755 2756 if (lstp->t_tspec == CHAR && !lstp->t_const && 2757 is_direct_function_call(rn, &function_name) && 2758 is_unconst_function(function_name) && 2759 is_first_arg_const_char_pointer(rn)) { 2760 /* call to '%s' effectively discards 'const' from argument */ 2761 warning(346, function_name); 2762 } 2763 2764 if (!lstp->t_const && 2765 is_direct_function_call(rn, &function_name) && 2766 strcmp(function_name, "bsearch") == 0 && 2767 is_second_arg_const_pointer(rn)) { 2768 /* call to '%s' effectively discards 'const' from argument */ 2769 warning(346, function_name); 2770 } 2771 } 2772 2773 static bool 2774 check_assign_void_pointer_compat(op_t op, int arg, 2775 const type_t *const ltp, tspec_t const lt, 2776 const type_t *const lstp, tspec_t const lst, 2777 const tnode_t *const rn, 2778 const type_t *const rtp, tspec_t const rt, 2779 const type_t *const rstp, tspec_t const rst) 2780 { 2781 if (!(lt == PTR && rt == PTR && (lst == VOID || rst == VOID || 2782 types_compatible(lstp, rstp, 2783 true, false, NULL)))) 2784 return false; 2785 2786 /* compatible pointer types (qualifiers ignored) */ 2787 if (allow_c90 && 2788 ((!lstp->t_const && rstp->t_const) || 2789 (!lstp->t_volatile && rstp->t_volatile))) { 2790 /* left side has not all qualifiers of right */ 2791 switch (op) { 2792 case INIT: 2793 case RETURN: 2794 /* incompatible pointer types to '%s' and '%s' */ 2795 warning(182, type_name(lstp), type_name(rstp)); 2796 break; 2797 case FARG: 2798 /* converting '%s' to incompatible '%s' ... */ 2799 warning(153, 2800 type_name(rtp), type_name(ltp), arg); 2801 break; 2802 default: 2803 /* operands of '%s' have incompatible pointer ... */ 2804 warning(128, op_name(op), 2805 type_name(lstp), type_name(rstp)); 2806 break; 2807 } 2808 } 2809 2810 if (allow_c90) 2811 check_unconst_function(lstp, rn); 2812 2813 return true; 2814 } 2815 2816 static bool 2817 check_assign_pointer_integer(op_t op, int arg, 2818 const type_t *const ltp, tspec_t const lt, 2819 const type_t *const rtp, tspec_t const rt) 2820 { 2821 2822 if (!((lt == PTR && is_integer(rt)) || (is_integer(lt) && rt == PTR))) 2823 return false; 2824 2825 const char *lx = lt == PTR ? "pointer" : "integer"; 2826 const char *rx = rt == PTR ? "pointer" : "integer"; 2827 2828 switch (op) { 2829 case INIT: 2830 case RETURN: 2831 /* illegal combination of %s '%s' and %s '%s' */ 2832 warning(183, lx, type_name(ltp), rx, type_name(rtp)); 2833 break; 2834 case FARG: 2835 /* illegal combination of %s '%s' and %s '%s', arg #%d */ 2836 warning(154, 2837 lx, type_name(ltp), rx, type_name(rtp), arg); 2838 break; 2839 default: 2840 /* illegal combination of %s '%s' and %s '%s', op '%s' */ 2841 warning(123, 2842 lx, type_name(ltp), rx, type_name(rtp), op_name(op)); 2843 break; 2844 } 2845 return true; 2846 } 2847 2848 static bool 2849 check_assign_pointer(op_t op, int arg, 2850 const type_t *ltp, tspec_t lt, 2851 const type_t *rtp, tspec_t rt) 2852 { 2853 if (!(lt == PTR && rt == PTR)) 2854 return false; 2855 2856 if (op == FARG) 2857 /* converting '%s' to incompatible '%s' for ... */ 2858 warning(153, type_name(rtp), type_name(ltp), arg); 2859 else 2860 warn_incompatible_pointers(op, ltp, rtp); 2861 return true; 2862 } 2863 2864 static void 2865 warn_assign(op_t op, int arg, 2866 const type_t *ltp, tspec_t lt, 2867 const type_t *rtp, tspec_t rt) 2868 { 2869 switch (op) { 2870 case INIT: 2871 /* cannot initialize '%s' from '%s' */ 2872 error(185, type_name(ltp), type_name(rtp)); 2873 break; 2874 case RETURN: 2875 /* function has return type '%s' but returns '%s' */ 2876 error(211, type_name(ltp), type_name(rtp)); 2877 break; 2878 case FARG: 2879 /* passing '%s' to incompatible '%s', arg #%d */ 2880 warning(155, type_name(rtp), type_name(ltp), arg); 2881 break; 2882 default: 2883 warn_incompatible_types(op, ltp, lt, rtp, rt); 2884 break; 2885 } 2886 } 2887 2888 /* 2889 * Checks type compatibility for ASSIGN, INIT, FARG and RETURN 2890 * and prints warnings/errors if necessary. 2891 * Returns whether the types are (almost) compatible. 2892 */ 2893 static bool 2894 check_assign_types_compatible(op_t op, int arg, 2895 const tnode_t *ln, const tnode_t *rn) 2896 { 2897 tspec_t lt, rt, lst = NO_TSPEC, rst = NO_TSPEC; 2898 type_t *ltp, *rtp, *lstp = NULL, *rstp = NULL; 2899 2900 if ((lt = (ltp = ln->tn_type)->t_tspec) == PTR) 2901 lst = (lstp = ltp->t_subt)->t_tspec; 2902 if ((rt = (rtp = rn->tn_type)->t_tspec) == PTR) 2903 rst = (rstp = rtp->t_subt)->t_tspec; 2904 2905 if (lt == BOOL && is_scalar(rt)) /* C99 6.3.1.2 */ 2906 return true; 2907 2908 if (is_arithmetic(lt) && (is_arithmetic(rt) || rt == BOOL)) 2909 return true; 2910 2911 if (is_struct_or_union(lt) && is_struct_or_union(rt)) 2912 /* both are struct or union */ 2913 return ltp->t_sou == rtp->t_sou; 2914 2915 /* a null pointer may be assigned to any pointer */ 2916 if (lt == PTR && is_null_pointer(rn)) { 2917 if (is_integer(rn->tn_type->t_tspec)) 2918 /* implicit conversion from integer 0 to pointer ... */ 2919 query_message(15, type_name(ltp)); 2920 return true; 2921 } 2922 2923 check_assign_void_pointer(op, arg, lt, lst, rt, rst); 2924 2925 if (check_assign_void_pointer_compat(op, arg, 2926 ltp, lt, lstp, lst, rn, rtp, rt, rstp, rst)) 2927 return true; 2928 2929 if (check_assign_pointer_integer(op, arg, ltp, lt, rtp, rt)) 2930 return true; 2931 2932 if (check_assign_pointer(op, arg, ltp, lt, rtp, rt)) 2933 return true; 2934 2935 warn_assign(op, arg, ltp, lt, rtp, rt); 2936 return false; 2937 } 2938 2939 static bool 2940 has_side_effect(const tnode_t *tn) /* NOLINT(misc-no-recursion) */ 2941 { 2942 op_t op = tn->tn_op; 2943 2944 if (modtab[op].m_has_side_effect) 2945 return true; 2946 2947 if (op == CVT && tn->tn_type->t_tspec == VOID) 2948 return has_side_effect(tn->tn_left); 2949 2950 /* XXX: Why not has_side_effect(tn->tn_left) as well? */ 2951 if (op == LOGAND || op == LOGOR) 2952 return has_side_effect(tn->tn_right); 2953 2954 /* XXX: Why not has_side_effect(tn->tn_left) as well? */ 2955 if (op == QUEST) 2956 return has_side_effect(tn->tn_right); 2957 2958 if (op == COLON || op == COMMA) { 2959 return has_side_effect(tn->tn_left) || 2960 has_side_effect(tn->tn_right); 2961 } 2962 2963 return false; 2964 } 2965 2966 static bool 2967 is_void_cast(const tnode_t *tn) 2968 { 2969 2970 return tn->tn_op == CVT && tn->tn_cast && 2971 tn->tn_type->t_tspec == VOID; 2972 } 2973 2974 static bool 2975 is_local_symbol(const tnode_t *tn) 2976 { 2977 2978 return tn->tn_op == LOAD && 2979 tn->tn_left->tn_op == NAME && 2980 tn->tn_left->tn_sym->s_scl == AUTO; 2981 } 2982 2983 static bool 2984 is_int_constant_zero(const tnode_t *tn) 2985 { 2986 2987 return tn->tn_op == CON && 2988 tn->tn_type->t_tspec == INT && 2989 tn->tn_val.u.integer == 0; 2990 } 2991 2992 static void 2993 check_null_effect(const tnode_t *tn) 2994 { 2995 2996 if (hflag && 2997 !has_side_effect(tn) && 2998 !(is_void_cast(tn) && is_local_symbol(tn->tn_left)) && 2999 !(is_void_cast(tn) && is_int_constant_zero(tn->tn_left))) { 3000 /* expression has null effect */ 3001 warning(129); 3002 } 3003 } 3004 3005 /* 3006 * Check the types for specific operators and type combinations. 3007 * 3008 * At this point, the operands already conform to the type requirements of 3009 * the operator, such as being integer, floating or scalar. 3010 */ 3011 static bool 3012 typeok_op(op_t op, int arg, 3013 const tnode_t *ln, const type_t *ltp, tspec_t lt, 3014 const tnode_t *rn, const type_t *rtp, tspec_t rt) 3015 { 3016 switch (op) { 3017 case ARROW: 3018 return typeok_arrow(lt); 3019 case POINT: 3020 return typeok_point(ln, ltp, lt); 3021 case INCBEF: 3022 case DECBEF: 3023 case INCAFT: 3024 case DECAFT: 3025 return typeok_incdec(op, ln, ltp); 3026 case INDIR: 3027 return typeok_indir(ltp, lt); 3028 case ADDR: 3029 return typeok_address(op, ln, ltp, lt); 3030 case PLUS: 3031 return typeok_plus(op, ltp, lt, rtp, rt); 3032 case MINUS: 3033 return typeok_minus(op, ltp, lt, rtp, rt); 3034 case SHL: 3035 typeok_shl(op, lt, rt); 3036 goto shift; 3037 case SHR: 3038 typeok_shr(op, ln, lt, rn, rt); 3039 shift: 3040 typeok_shift(ltp, lt, rn, rt); 3041 break; 3042 case LT: 3043 case LE: 3044 case GT: 3045 case GE: 3046 compare: 3047 return typeok_compare(op, ln, ltp, lt, rn, rtp, rt); 3048 case EQ: 3049 case NE: 3050 if (is_typeok_eq(ln, lt, rn, rt)) 3051 break; 3052 goto compare; 3053 case QUEST: 3054 return typeok_quest(lt, rn); 3055 case COLON: 3056 return typeok_colon(ln, ltp, lt, rn, rtp, rt); 3057 case ASSIGN: 3058 case INIT: 3059 case FARG: 3060 case RETURN: 3061 if (!check_assign_types_compatible(op, arg, ln, rn)) 3062 return false; 3063 goto assign; 3064 case MULASS: 3065 case DIVASS: 3066 case MODASS: 3067 goto assign; 3068 case ADDASS: 3069 case SUBASS: 3070 if ((lt == PTR && !is_integer(rt)) || rt == PTR) { 3071 warn_incompatible_types(op, ltp, lt, rtp, rt); 3072 return false; 3073 } 3074 goto assign; 3075 case SHLASS: 3076 goto assign; 3077 case SHRASS: 3078 if (pflag && !is_uinteger(lt) && 3079 !(!allow_c90 && is_uinteger(rt))) { 3080 /* bitwise '%s' on signed value possibly nonportable */ 3081 warning(117, op_name(op)); 3082 } 3083 goto assign; 3084 case ANDASS: 3085 case XORASS: 3086 case ORASS: 3087 assign: 3088 return typeok_assign(op, ln, ltp, lt); 3089 case COMMA: 3090 if (!modtab[ln->tn_op].m_has_side_effect) 3091 check_null_effect(ln); 3092 break; 3093 default: 3094 break; 3095 } 3096 return true; 3097 } 3098 3099 /* Prints a warning if a strange operator is used on an enum type. */ 3100 static void 3101 check_bad_enum_operation(op_t op, const tnode_t *ln, const tnode_t *rn) 3102 { 3103 3104 if (!eflag) 3105 return; 3106 3107 /* Allow enum in array indices. */ 3108 if (op == PLUS && 3109 ((ln->tn_type->t_is_enum && rn->tn_type->t_tspec == PTR) || 3110 (rn->tn_type->t_is_enum && ln->tn_type->t_tspec == PTR))) { 3111 return; 3112 } 3113 3114 /* dubious operation '%s' on enum */ 3115 warning(241, op_name(op)); 3116 } 3117 3118 /* Prints a warning if an operator is applied to two different enum types. */ 3119 static void 3120 check_enum_type_mismatch(op_t op, int arg, const tnode_t *ln, const tnode_t *rn) 3121 { 3122 const mod_t *mp = &modtab[op]; 3123 3124 if (ln->tn_type->t_enum != rn->tn_type->t_enum) { 3125 switch (op) { 3126 case INIT: 3127 /* enum type mismatch between '%s' and '%s' in ... */ 3128 warning(210, 3129 type_name(ln->tn_type), type_name(rn->tn_type)); 3130 break; 3131 case FARG: 3132 /* function expects '%s', passing '%s' for arg #%d */ 3133 warning(156, 3134 type_name(ln->tn_type), type_name(rn->tn_type), 3135 arg); 3136 break; 3137 case RETURN: 3138 /* function has return type '%s' but returns '%s' */ 3139 warning(211, 3140 type_name(ln->tn_type), type_name(rn->tn_type)); 3141 break; 3142 default: 3143 /* enum type mismatch: '%s' '%s' '%s' */ 3144 warning(130, type_name(ln->tn_type), op_name(op), 3145 type_name(rn->tn_type)); 3146 break; 3147 } 3148 } else if (Pflag && eflag && mp->m_comparison && op != EQ && op != NE) 3149 /* operator '%s' assumes that '%s' is ordered */ 3150 warning(243, op_name(op), type_name(ln->tn_type)); 3151 } 3152 3153 /* Prints a warning if the operands mix between enum and integer. */ 3154 static void 3155 check_enum_int_mismatch(op_t op, int arg, const tnode_t *ln, const tnode_t *rn) 3156 { 3157 3158 if (!eflag) 3159 return; 3160 3161 switch (op) { 3162 case INIT: 3163 /* 3164 * Initialization with 0 is allowed. Otherwise, all implicit 3165 * initializations would need to be warned upon as well. 3166 */ 3167 if (!rn->tn_type->t_is_enum && rn->tn_op == CON && 3168 is_integer(rn->tn_type->t_tspec) && 3169 rn->tn_val.u.integer == 0) { 3170 return; 3171 } 3172 /* initialization of '%s' with '%s' */ 3173 warning(277, type_name(ln->tn_type), type_name(rn->tn_type)); 3174 break; 3175 case FARG: 3176 /* combination of '%s' and '%s', arg #%d */ 3177 warning(278, 3178 type_name(ln->tn_type), type_name(rn->tn_type), arg); 3179 break; 3180 case RETURN: 3181 /* combination of '%s' and '%s' in return */ 3182 warning(279, type_name(ln->tn_type), type_name(rn->tn_type)); 3183 break; 3184 default: 3185 /* combination of '%s' and '%s', op '%s' */ 3186 warning(242, type_name(ln->tn_type), type_name(rn->tn_type), 3187 op_name(op)); 3188 break; 3189 } 3190 } 3191 3192 static void 3193 typeok_enum(op_t op, const mod_t *mp, int arg, 3194 const tnode_t *ln, const type_t *ltp, 3195 const tnode_t *rn, const type_t *rtp) 3196 { 3197 if (mp->m_bad_on_enum && 3198 (ltp->t_is_enum || (mp->m_binary && rtp->t_is_enum))) { 3199 check_bad_enum_operation(op, ln, rn); 3200 } else if (mp->m_valid_on_enum && 3201 (ltp->t_is_enum && rtp != NULL && rtp->t_is_enum)) { 3202 check_enum_type_mismatch(op, arg, ln, rn); 3203 } else if (mp->m_valid_on_enum && 3204 (ltp->t_is_enum || (rtp != NULL && rtp->t_is_enum))) { 3205 check_enum_int_mismatch(op, arg, ln, rn); 3206 } 3207 } 3208 3209 /* Perform most type checks. Return whether the types are ok. */ 3210 bool 3211 typeok(op_t op, int arg, const tnode_t *ln, const tnode_t *rn) 3212 { 3213 3214 const mod_t *mp = &modtab[op]; 3215 3216 type_t *ltp = ln->tn_type; 3217 tspec_t lt = ltp->t_tspec; 3218 3219 type_t *rtp = mp->m_binary ? rn->tn_type : NULL; 3220 tspec_t rt = mp->m_binary ? rtp->t_tspec : NO_TSPEC; 3221 3222 if (Tflag && !typeok_scalar_strict_bool(op, mp, arg, ln, rn)) 3223 return false; 3224 if (!typeok_scalar(op, mp, ltp, lt, rtp, rt)) 3225 return false; 3226 3227 if (!typeok_op(op, arg, ln, ltp, lt, rn, rtp, rt)) 3228 return false; 3229 3230 typeok_enum(op, mp, arg, ln, ltp, rn, rtp); 3231 return true; 3232 } 3233 3234 /* In traditional C, keep unsigned and promote FLOAT to DOUBLE. */ 3235 static tspec_t 3236 promote_trad(tspec_t t) 3237 { 3238 3239 if (t == UCHAR || t == USHORT) 3240 return UINT; 3241 if (t == CHAR || t == SCHAR || t == SHORT) 3242 return INT; 3243 if (t == FLOAT) 3244 return DOUBLE; 3245 if (t == ENUM) 3246 return INT; 3247 return t; 3248 } 3249 3250 /* 3251 * C99 6.3.1.1p2 requires for types with lower rank than int that "If an int 3252 * can represent all the values of the original type, the value is converted 3253 * to an int; otherwise it is converted to an unsigned int", and that "All 3254 * other types are unchanged by the integer promotions". 3255 */ 3256 static tspec_t 3257 promote_c90(const tnode_t *tn, tspec_t t, bool farg) 3258 { 3259 if (tn->tn_type->t_bitfield) { 3260 unsigned int width = tn->tn_type->t_bit_field_width; 3261 unsigned int int_width = size_in_bits(INT); 3262 // XXX: What about _Bool bit-fields, since C99? 3263 if (width < int_width) 3264 return INT; 3265 if (width == int_width) 3266 return is_uinteger(t) ? UINT : INT; 3267 return t; 3268 } 3269 3270 if (t == CHAR || t == SCHAR) 3271 return INT; 3272 if (t == UCHAR) 3273 return size_in_bits(CHAR) < size_in_bits(INT) ? INT : UINT; 3274 if (t == SHORT) 3275 return INT; 3276 if (t == USHORT) 3277 return size_in_bits(SHORT) < size_in_bits(INT) ? INT : UINT; 3278 if (t == ENUM) 3279 return INT; 3280 if (farg && t == FLOAT) 3281 return DOUBLE; 3282 return t; 3283 } 3284 3285 /* 3286 * Performs the "integer promotions" (C99 6.3.1.1p2), which convert small 3287 * integer types to either int or unsigned int. 3288 * 3289 * If allow_c90 is unset or the operand is a function argument with no type 3290 * information (no prototype or variable # of args), converts float to double. 3291 */ 3292 tnode_t * 3293 promote(op_t op, bool farg, tnode_t *tn) 3294 { 3295 3296 tspec_t ot = tn->tn_type->t_tspec; 3297 if (!is_arithmetic(ot)) 3298 return tn; 3299 3300 tspec_t nt = allow_c90 ? promote_c90(tn, ot, farg) : promote_trad(ot); 3301 if (nt == ot) 3302 return tn; 3303 3304 type_t *ntp = expr_dup_type(tn->tn_type); 3305 ntp->t_tspec = nt; 3306 /* 3307 * Keep t_is_enum even though t_tspec gets converted from 3308 * ENUM to INT, so we are later able to check compatibility 3309 * of enum types. 3310 */ 3311 return convert(op, 0, ntp, tn); 3312 } 3313 3314 static void 3315 convert_integer_from_floating(op_t op, const type_t *tp, const tnode_t *tn) 3316 { 3317 3318 if (op == CVT) 3319 /* cast from floating point '%s' to integer '%s' */ 3320 query_message(2, type_name(tn->tn_type), type_name(tp)); 3321 else 3322 /* implicit conversion from floating point '%s' to ... */ 3323 query_message(1, type_name(tn->tn_type), type_name(tp)); 3324 } 3325 3326 static bool 3327 should_warn_about_prototype_conversion(tspec_t nt, 3328 tspec_t ot, const tnode_t *ptn) 3329 { 3330 3331 if (nt == ot) 3332 return false; 3333 3334 if (nt == ENUM && ot == INT) 3335 return false; 3336 3337 if (is_floating(nt) != is_floating(ot) || 3338 portable_rank_cmp(nt, ot) != 0) { 3339 /* representation and/or width change */ 3340 if (!is_integer(ot)) 3341 return true; 3342 /* 3343 * XXX: Investigate whether this rule makes sense; see 3344 * tests/usr.bin/xlint/lint1/platform_long.c. 3345 */ 3346 return portable_rank_cmp(ot, INT) > 0; 3347 } 3348 3349 if (!hflag) 3350 return false; 3351 3352 /* 3353 * If the types differ only in sign and the argument has the same 3354 * representation in both types, print no warning. 3355 */ 3356 if (ptn->tn_op == CON && is_integer(nt) && 3357 signed_type(nt) == signed_type(ot) && 3358 !msb(ptn->tn_val.u.integer, ot)) 3359 return false; 3360 3361 return true; 3362 } 3363 3364 /* 3365 * Warn if a prototype causes a type conversion that is different from what 3366 * would happen to the same argument in the absence of a prototype. This 3367 * check is intended for code that needs to stay compatible with pre-C90 C. 3368 * 3369 * Errors/warnings about illegal type combinations are already printed 3370 * in check_assign_types_compatible(). 3371 */ 3372 static void 3373 check_prototype_conversion(int arg, tspec_t nt, tspec_t ot, type_t *tp, 3374 tnode_t *tn) 3375 { 3376 3377 if (!is_arithmetic(nt) || !is_arithmetic(ot)) 3378 return; 3379 3380 /* 3381 * If the type of the formal parameter is char/short, a warning 3382 * would be useless, because functions declared the old style 3383 * can't expect char/short arguments. 3384 */ 3385 if (nt == CHAR || nt == SCHAR || nt == UCHAR || 3386 nt == SHORT || nt == USHORT) 3387 return; 3388 3389 /* apply the default promotion */ 3390 tnode_t *ptn = promote(NOOP, true, tn); 3391 ot = ptn->tn_type->t_tspec; 3392 3393 if (should_warn_about_prototype_conversion(nt, ot, ptn)) { 3394 /* argument %d is converted from '%s' to '%s' ... */ 3395 warning(259, arg, type_name(tn->tn_type), type_name(tp)); 3396 } 3397 } 3398 3399 /* 3400 * When converting a large integer type to a small integer type, in some 3401 * cases the value of the actual expression is further restricted than the 3402 * type bounds, such as in (expr & 0xFF) or (expr % 100) or (expr >> 24). 3403 */ 3404 static bool 3405 can_represent(const type_t *tp, const tnode_t *tn) 3406 { 3407 3408 debug_step("%s: type '%s'", __func__, type_name(tp)); 3409 debug_node(tn); 3410 3411 uint64_t nmask = value_bits(width_in_bits(tp)); 3412 if (!is_uinteger(tp->t_tspec)) 3413 nmask >>= 1; 3414 3415 integer_constraints c = ic_expr(tn); 3416 if ((~c.bclr & ~nmask) == 0) 3417 return true; 3418 3419 integer_constraints tpc = ic_any(tp); 3420 if (is_uinteger(tp->t_tspec) 3421 ? tpc.umin <= c.umin && tpc.umax >= c.umax 3422 : tpc.smin <= c.smin && tpc.smax >= c.smax) 3423 return true; 3424 3425 return false; 3426 } 3427 3428 static bool 3429 should_warn_about_integer_conversion(const type_t *ntp, tspec_t nt, 3430 const tnode_t *otn, tspec_t ot) 3431 { 3432 3433 // XXX: The portable_rank_cmp aims at portable mode, independent of the 3434 // current platform, while can_represent acts on the actual type sizes 3435 // from the current platform. This mix is inconsistent, but anything 3436 // else would make the exact conditions too complicated to grasp. 3437 if (aflag > 0 && portable_rank_cmp(nt, ot) < 0) { 3438 if (ot == LONG || ot == ULONG 3439 || ot == LLONG || ot == ULLONG 3440 #ifdef INT128_SIZE 3441 || ot == INT128 || ot == UINT128 3442 #endif 3443 || aflag > 1) 3444 return !can_represent(ntp, otn); 3445 } 3446 return false; 3447 } 3448 3449 static void 3450 convert_integer_from_integer(op_t op, int arg, tspec_t nt, tspec_t ot, 3451 type_t *tp, tnode_t *tn) 3452 { 3453 3454 if (tn->tn_op == CON) 3455 return; 3456 3457 if (op == CVT) 3458 return; 3459 3460 if (Pflag && pflag && aflag > 0 && 3461 portable_rank_cmp(nt, ot) > 0 && 3462 is_uinteger(nt) != is_uinteger(ot)) { 3463 if (op == FARG) { 3464 /* conversion to '%s' may sign-extend ... */ 3465 warning(297, type_name(tp), arg); 3466 } else { 3467 /* conversion to '%s' may sign-extend ... */ 3468 warning(131, type_name(tp)); 3469 } 3470 } 3471 3472 if (Pflag && portable_rank_cmp(nt, ot) > 0 && 3473 (tn->tn_op == PLUS || tn->tn_op == MINUS || tn->tn_op == MULT || 3474 tn->tn_op == SHL)) { 3475 /* suggest cast from '%s' to '%s' on op '%s' to ... */ 3476 warning(324, type_name(gettyp(ot)), type_name(tp), 3477 op_name(tn->tn_op)); 3478 } 3479 3480 if (should_warn_about_integer_conversion(tp, nt, tn, ot)) { 3481 if (op == FARG) { 3482 /* conversion from '%s' to '%s' may lose ... */ 3483 warning(298, 3484 type_name(tn->tn_type), type_name(tp), arg); 3485 } else { 3486 /* conversion from '%s' to '%s' may lose accuracy */ 3487 warning(132, 3488 type_name(tn->tn_type), type_name(tp)); 3489 } 3490 } 3491 3492 if (any_query_enabled && is_uinteger(nt) != is_uinteger(ot)) 3493 /* implicit conversion changes sign from '%s' to '%s' */ 3494 query_message(3, type_name(tn->tn_type), type_name(tp)); 3495 } 3496 3497 static void 3498 convert_integer_from_pointer(op_t op, tspec_t nt, type_t *tp, tnode_t *tn) 3499 { 3500 3501 if (tn->tn_op == CON) 3502 return; 3503 if (op != CVT) 3504 return; /* We already got an error. */ 3505 if (portable_rank_cmp(nt, PTR) >= 0) 3506 return; 3507 3508 if (pflag && size_in_bits(nt) >= size_in_bits(PTR)) { 3509 /* conversion of pointer to '%s' may lose bits */ 3510 warning(134, type_name(tp)); 3511 } else { 3512 /* conversion of pointer to '%s' loses bits */ 3513 warning(133, type_name(tp)); 3514 } 3515 } 3516 3517 static bool 3518 struct_starts_with(const type_t *struct_tp, const type_t *member_tp) 3519 { 3520 3521 return struct_tp->t_sou->sou_first_member != NULL && 3522 types_compatible(struct_tp->t_sou->sou_first_member->s_type, 3523 member_tp, true, false, NULL); 3524 } 3525 3526 static bool 3527 is_byte_array(const type_t *tp) 3528 { 3529 3530 return tp->t_tspec == ARRAY && 3531 (tp->t_subt->t_tspec == CHAR || tp->t_subt->t_tspec == UCHAR); 3532 } 3533 3534 static bool 3535 union_contains(const type_t *utp, const type_t *mtp) 3536 { 3537 for (const sym_t *mem = utp->t_sou->sou_first_member; 3538 mem != NULL; mem = mem->s_next) { 3539 if (types_compatible(mem->s_type, mtp, true, false, NULL)) 3540 return true; 3541 } 3542 return false; 3543 } 3544 3545 static bool 3546 should_warn_about_pointer_cast(const type_t *nstp, tspec_t nst, 3547 const type_t *ostp, tspec_t ost) 3548 { 3549 3550 while (nst == ARRAY) 3551 nstp = nstp->t_subt, nst = nstp->t_tspec; 3552 while (ost == ARRAY) 3553 ostp = ostp->t_subt, ost = ostp->t_tspec; 3554 3555 if (nst == STRUCT && ost == STRUCT && 3556 (struct_starts_with(nstp, ostp) || 3557 struct_starts_with(ostp, nstp))) 3558 return false; 3559 3560 if (is_incomplete(nstp) || is_incomplete(ostp)) 3561 return false; 3562 3563 if (nst == CHAR || nst == UCHAR) 3564 return false; /* for the sake of traditional C code */ 3565 if (ost == CHAR || ost == UCHAR) 3566 return false; /* for the sake of traditional C code */ 3567 3568 /* Allow cast between pointers to sockaddr variants. */ 3569 if (nst == STRUCT && ost == STRUCT) { 3570 const sym_t *nmem = nstp->t_sou->sou_first_member; 3571 const sym_t *omem = ostp->t_sou->sou_first_member; 3572 while (nmem != NULL && omem != NULL && 3573 types_compatible(nmem->s_type, omem->s_type, 3574 true, false, NULL)) 3575 nmem = nmem->s_next, omem = omem->s_next; 3576 if (nmem != NULL && is_byte_array(nmem->s_type)) 3577 return false; 3578 if (omem != NULL && is_byte_array(omem->s_type)) 3579 return false; 3580 if (nmem == NULL && omem == NULL) 3581 return false; 3582 } 3583 3584 if (nst == UNION || ost == UNION) { 3585 const type_t *union_tp = nst == UNION ? nstp : ostp; 3586 const type_t *other_tp = nst == UNION ? ostp : nstp; 3587 if (union_contains(union_tp, other_tp)) 3588 return false; 3589 } 3590 3591 if (is_struct_or_union(nst) && is_struct_or_union(ost)) 3592 return nstp->t_sou != ostp->t_sou; 3593 3594 enum rank_kind rk1 = type_properties(nst)->tt_rank_kind; 3595 enum rank_kind rk2 = type_properties(ost)->tt_rank_kind; 3596 if (rk1 != rk2 || rk1 == RK_NONE) 3597 return true; 3598 3599 return portable_rank_cmp(nst, ost) != 0; 3600 } 3601 3602 static void 3603 convert_pointer_from_pointer(type_t *ntp, tnode_t *tn) 3604 { 3605 const type_t *nstp = ntp->t_subt; 3606 const type_t *otp = tn->tn_type; 3607 const type_t *ostp = otp->t_subt; 3608 tspec_t nst = nstp->t_tspec; 3609 tspec_t ost = ostp->t_tspec; 3610 3611 if (nst == VOID || ost == VOID) { 3612 /* TODO: C99 behaves like C90 here. */ 3613 if ((!allow_trad && !allow_c99) && (nst == FUNC || ost == FUNC)) { 3614 const char *nts, *ots; 3615 /* null pointers are already handled in convert() */ 3616 *(nst == FUNC ? &nts : &ots) = "function pointer"; 3617 *(nst == VOID ? &nts : &ots) = "'void *'"; 3618 /* conversion of %s to %s requires a cast */ 3619 warning(303, ots, nts); 3620 } 3621 return; 3622 } 3623 if (nst == FUNC && ost == FUNC) 3624 return; 3625 if (nst == FUNC || ost == FUNC) { 3626 /* converting '%s' to '%s' is questionable */ 3627 warning(229, type_name(otp), type_name(ntp)); 3628 return; 3629 } 3630 3631 if (hflag && alignment_in_bits(nstp) > alignment_in_bits(ostp) && 3632 ost != CHAR && ost != UCHAR && 3633 !is_incomplete(ostp) && 3634 !(nst == UNION && union_contains(nstp, ostp))) { 3635 /* converting '%s' to '%s' increases alignment ... */ 3636 warning(135, type_name(otp), type_name(ntp), 3637 alignment_in_bits(ostp) / CHAR_SIZE, 3638 alignment_in_bits(nstp) / CHAR_SIZE); 3639 } 3640 3641 if (cflag && should_warn_about_pointer_cast(nstp, nst, ostp, ost)) { 3642 /* pointer cast from '%s' to '%s' may be troublesome */ 3643 warning(247, type_name(otp), type_name(ntp)); 3644 } 3645 } 3646 3647 /* 3648 * Insert a conversion operator, which converts the type of the node 3649 * to another given type. 3650 * 3651 * Possible values for 'op': 3652 * CVT a cast-expression 3653 * binary integer promotion for one of the operands, or a usual 3654 * arithmetic conversion 3655 * binary plain or compound assignments to bit-fields 3656 * FARG 'arg' is the number of the parameter (used for warnings) 3657 * NOOP several other implicit conversions 3658 * ... 3659 */ 3660 tnode_t * 3661 convert(op_t op, int arg, type_t *tp, tnode_t *tn) 3662 { 3663 tspec_t nt = tp->t_tspec; 3664 tspec_t ot = tn->tn_type->t_tspec; 3665 3666 if (allow_trad && allow_c90 && op == FARG) 3667 check_prototype_conversion(arg, nt, ot, tp, tn); 3668 3669 if (nt == BOOL) { 3670 /* No further checks. */ 3671 3672 } else if (is_integer(nt)) { 3673 if (ot == BOOL) { 3674 /* No further checks. */ 3675 } else if (is_integer(ot)) 3676 convert_integer_from_integer(op, arg, nt, ot, tp, tn); 3677 else if (is_floating(ot)) 3678 convert_integer_from_floating(op, tp, tn); 3679 else if (ot == PTR) 3680 convert_integer_from_pointer(op, nt, tp, tn); 3681 3682 } else if (is_floating(nt)) { 3683 /* No further checks. */ 3684 3685 } else if (nt == PTR) { 3686 if (is_null_pointer(tn)) { 3687 /* a null pointer may be assigned to any pointer. */ 3688 } else if (ot == PTR && op == CVT) 3689 convert_pointer_from_pointer(tp, tn); 3690 } 3691 3692 tnode_t *ntn = expr_alloc_tnode(); 3693 ntn->tn_op = CVT; 3694 ntn->tn_type = tp; 3695 ntn->tn_cast = op == CVT; 3696 ntn->tn_sys |= tn->tn_sys; 3697 ntn->tn_right = NULL; 3698 if (tn->tn_op != CON || nt == VOID) { 3699 ntn->tn_left = tn; 3700 } else { 3701 ntn->tn_op = CON; 3702 convert_constant(op, arg, ntn->tn_type, &ntn->tn_val, 3703 &tn->tn_val); 3704 } 3705 3706 return ntn; 3707 } 3708 3709 static void 3710 convert_constant_floating(op_t op, int arg, tspec_t ot, const type_t *tp, 3711 tspec_t nt, val_t *v, val_t *nv) 3712 { 3713 long double max = 0.0, min = 0.0; 3714 3715 switch (nt) { 3716 case CHAR: 3717 max = TARG_CHAR_MAX; min = TARG_CHAR_MIN; break; 3718 case UCHAR: 3719 max = TARG_UCHAR_MAX; min = 0; break; 3720 case SCHAR: 3721 max = TARG_SCHAR_MAX; min = TARG_SCHAR_MIN; break; 3722 case SHORT: 3723 max = TARG_SHRT_MAX; min = TARG_SHRT_MIN; break; 3724 case USHORT: 3725 max = TARG_USHRT_MAX; min = 0; break; 3726 case ENUM: 3727 case INT: 3728 max = TARG_INT_MAX; min = TARG_INT_MIN; break; 3729 case UINT: 3730 max = TARG_UINT_MAX; min = 0; break; 3731 case LONG: 3732 max = TARG_LONG_MAX; min = TARG_LONG_MIN; break; 3733 case ULONG: 3734 max = TARG_ULONG_MAX; min = 0; break; 3735 case LLONG: 3736 max = LLONG_MAX; min = LLONG_MIN; break; 3737 case ULLONG: 3738 max = ULLONG_MAX; min = 0; break; 3739 case FLOAT: 3740 case FCOMPLEX: 3741 max = FLT_MAX; min = -FLT_MAX; break; 3742 case DOUBLE: 3743 case DCOMPLEX: 3744 max = DBL_MAX; min = -DBL_MAX; break; 3745 case PTR: 3746 /* Already got an error because of float --> ptr */ 3747 case LDOUBLE: 3748 case LCOMPLEX: 3749 /* LINTED 248 */ 3750 max = LDBL_MAX; min = -max; break; 3751 default: 3752 lint_assert(/*CONSTCOND*/false); 3753 } 3754 if (v->u.floating > max || v->u.floating < min) { 3755 lint_assert(nt != LDOUBLE); 3756 if (op == FARG) { 3757 /* conversion of '%s' to '%s' is out of range, ... */ 3758 warning(295, 3759 type_name(gettyp(ot)), type_name(tp), arg); 3760 } else { 3761 /* conversion of '%s' to '%s' is out of range */ 3762 warning(119, type_name(gettyp(ot)), type_name(tp)); 3763 } 3764 v->u.floating = v->u.floating > 0 ? max : min; 3765 } 3766 3767 if (nt == FLOAT || nt == FCOMPLEX) 3768 nv->u.floating = (float)v->u.floating; 3769 else if (nt == DOUBLE || nt == DCOMPLEX) 3770 nv->u.floating = (double)v->u.floating; 3771 else if (nt == LDOUBLE || nt == LCOMPLEX) 3772 nv->u.floating = v->u.floating; 3773 else 3774 nv->u.integer = (int64_t)v->u.floating; 3775 } 3776 3777 static bool 3778 convert_constant_to_floating(tspec_t nt, val_t *nv, 3779 tspec_t ot, const val_t *v) 3780 { 3781 if (nt == FLOAT) { 3782 nv->u.floating = (ot == PTR || is_uinteger(ot)) ? 3783 (float)(uint64_t)v->u.integer : (float)v->u.integer; 3784 } else if (nt == DOUBLE) { 3785 nv->u.floating = (ot == PTR || is_uinteger(ot)) ? 3786 (double)(uint64_t)v->u.integer : (double)v->u.integer; 3787 } else if (nt == LDOUBLE) { 3788 nv->u.floating = (ot == PTR || is_uinteger(ot)) 3789 ? (long double)(uint64_t)v->u.integer 3790 : (long double)v->u.integer; 3791 } else 3792 return false; 3793 return true; 3794 } 3795 3796 /* 3797 * Print a warning if bits which were set are lost due to the conversion. 3798 * This can happen with operator ORASS only. 3799 */ 3800 static void 3801 convert_constant_check_range_bitor(size_t nsz, size_t osz, const val_t *v, 3802 uint64_t xmask, op_t op) 3803 { 3804 if (nsz < osz && (v->u.integer & xmask) != 0) { 3805 /* constant truncated by conversion, op '%s' */ 3806 warning(306, op_name(op)); 3807 } 3808 } 3809 3810 /* 3811 * Print a warning if additional bits are not all 1 3812 * and the most significant bit of the old value is 1, 3813 * or if at least one (but not all) removed bit was 0. 3814 */ 3815 static void 3816 convert_constant_check_range_bitand(size_t nsz, size_t osz, 3817 uint64_t xmask, const val_t *nv, 3818 tspec_t ot, const val_t *v, 3819 const type_t *tp, op_t op) 3820 { 3821 if (nsz > osz && 3822 (nv->u.integer & bit((unsigned int)(osz - 1))) != 0 && 3823 (nv->u.integer & xmask) != xmask) { 3824 /* extra bits set to 0 in conversion of '%s' to '%s', ... */ 3825 warning(309, type_name(gettyp(ot)), 3826 type_name(tp), op_name(op)); 3827 } else if (nsz < osz && 3828 (v->u.integer & xmask) != xmask && 3829 (v->u.integer & xmask) != 0) { 3830 /* constant truncated by conversion, op '%s' */ 3831 warning(306, op_name(op)); 3832 } 3833 } 3834 3835 static void 3836 convert_constant_check_range_signed(op_t op, int arg) 3837 { 3838 if (op == ASSIGN) { 3839 /* assignment of negative constant to unsigned type */ 3840 warning(164); 3841 } else if (op == INIT) { 3842 /* initialization of unsigned with negative constant */ 3843 warning(221); 3844 } else if (op == FARG) { 3845 /* conversion of negative constant to unsigned type, ... */ 3846 warning(296, arg); 3847 } else if (modtab[op].m_comparison) { 3848 /* handled by check_integer_comparison() */ 3849 } else { 3850 /* conversion of negative constant to unsigned type */ 3851 warning(222); 3852 } 3853 } 3854 3855 /* 3856 * Loss of significant bit(s). All truncated bits of unsigned types or all 3857 * truncated bits plus the msb of the target for signed types are considered 3858 * to be significant bits. Loss of significant bits means that at least one 3859 * of the bits was set in an unsigned type or that at least one but not all 3860 * of the bits was set in a signed type. Loss of significant bits means that 3861 * it is not possible, also not with necessary casts, to convert back to the 3862 * original type. An example for a necessary cast is: 3863 * char c; int i; c = 128; 3864 * i = c; ** yields -128 ** 3865 * i = (unsigned char)c; ** yields 128 ** 3866 */ 3867 static void 3868 warn_constant_check_range_truncated(op_t op, int arg, const type_t *tp, 3869 tspec_t ot) 3870 { 3871 if (op == ASSIGN && tp->t_bitfield) 3872 /* precision lost in bit-field assignment */ 3873 warning(166); 3874 else if (op == ASSIGN) 3875 /* constant truncated by assignment */ 3876 warning(165); 3877 else if (op == INIT && tp->t_bitfield) 3878 /* bit-field initializer does not fit */ 3879 warning(180); 3880 else if (op == INIT) 3881 /* initializer does not fit */ 3882 warning(178); 3883 else if (op == CASE) 3884 /* case label affected by conversion */ 3885 warning(196); 3886 else if (op == FARG) 3887 /* conversion of '%s' to '%s' is out of range, arg #%d */ 3888 warning(295, type_name(gettyp(ot)), type_name(tp), arg); 3889 else 3890 /* conversion of '%s' to '%s' is out of range */ 3891 warning(119, type_name(gettyp(ot)), type_name(tp)); 3892 } 3893 3894 static void 3895 warn_constant_check_range_loss(op_t op, int arg, const type_t *tp, 3896 tspec_t ot) 3897 { 3898 if (op == ASSIGN && tp->t_bitfield) 3899 /* precision lost in bit-field assignment */ 3900 warning(166); 3901 else if (op == INIT && tp->t_bitfield) 3902 /* bit-field initializer out of range */ 3903 warning(11); 3904 else if (op == CASE) 3905 /* case label affected by conversion */ 3906 warning(196); 3907 else if (op == FARG) 3908 /* conversion of '%s' to '%s' is out of range, arg #%d */ 3909 warning(295, type_name(gettyp(ot)), type_name(tp), arg); 3910 else 3911 /* conversion of '%s' to '%s' is out of range */ 3912 warning(119, type_name(gettyp(ot)), type_name(tp)); 3913 } 3914 3915 static void 3916 convert_constant_check_range(tspec_t ot, const type_t *tp, tspec_t nt, 3917 op_t op, int arg, const val_t *v, val_t *nv) 3918 { 3919 unsigned int obitsz, nbitsz; 3920 uint64_t xmask, xmsk1; 3921 3922 obitsz = size_in_bits(ot); 3923 nbitsz = tp->t_bitfield ? tp->t_bit_field_width : size_in_bits(nt); 3924 xmask = value_bits(nbitsz) ^ value_bits(obitsz); 3925 xmsk1 = value_bits(nbitsz) ^ value_bits(obitsz - 1); 3926 /* 3927 * For bitwise operations we are not interested in the arithmetic 3928 * value, but in the bits itself. 3929 */ 3930 if (op == ORASS || op == BITOR || op == BITXOR) { 3931 convert_constant_check_range_bitor( 3932 nbitsz, obitsz, v, xmask, op); 3933 } else if (op == ANDASS || op == BITAND) { 3934 convert_constant_check_range_bitand( 3935 nbitsz, obitsz, xmask, nv, ot, v, tp, op); 3936 } else if ((nt != PTR && is_uinteger(nt)) && 3937 (ot != PTR && !is_uinteger(ot)) && 3938 v->u.integer < 0) 3939 convert_constant_check_range_signed(op, arg); 3940 else if (nv->u.integer != v->u.integer && nbitsz <= obitsz && 3941 (v->u.integer & xmask) != 0 && 3942 (is_uinteger(ot) || (v->u.integer & xmsk1) != xmsk1)) 3943 warn_constant_check_range_truncated(op, arg, tp, ot); 3944 else if (nv->u.integer != v->u.integer) 3945 warn_constant_check_range_loss(op, arg, tp, ot); 3946 } 3947 3948 /*- 3949 * Converts a typed constant to a constant of another type. 3950 * 3951 * op operator which requires conversion 3952 * arg if op is FARG, # of parameter 3953 * tp type to which to convert the constant 3954 * nv new constant 3955 * v old constant 3956 */ 3957 void 3958 convert_constant(op_t op, int arg, const type_t *tp, val_t *nv, val_t *v) 3959 { 3960 /* 3961 * TODO: make 'v' const; the name of this function does not suggest 3962 * that it modifies 'v'. 3963 */ 3964 tspec_t ot = v->v_tspec; 3965 tspec_t nt = nv->v_tspec = tp->t_tspec; 3966 bool range_check = false; 3967 3968 if (nt == BOOL) { /* C99 6.3.1.2 */ 3969 nv->v_unsigned_since_c90 = false; 3970 nv->u.integer = is_nonzero_val(v) ? 1 : 0; 3971 return; 3972 } 3973 3974 if (ot == FLOAT || ot == DOUBLE || ot == LDOUBLE) 3975 convert_constant_floating(op, arg, ot, tp, nt, v, nv); 3976 else if (!convert_constant_to_floating(nt, nv, ot, v)) { 3977 range_check = true; /* Check for lost precision. */ 3978 nv->u.integer = v->u.integer; 3979 } 3980 3981 if (allow_trad && allow_c90 && v->v_unsigned_since_c90 && 3982 (is_floating(nt) || ( 3983 (is_integer(nt) && !is_uinteger(nt) && 3984 portable_rank_cmp(nt, ot) > 0)))) { 3985 /* C90 treats constant as unsigned */ 3986 warning(157); 3987 v->v_unsigned_since_c90 = false; 3988 } 3989 3990 if (is_integer(nt)) { 3991 nv->u.integer = convert_integer(nv->u.integer, nt, 3992 tp->t_bitfield ? tp->t_bit_field_width : size_in_bits(nt)); 3993 } 3994 3995 if (range_check && op != CVT) 3996 convert_constant_check_range(ot, tp, nt, op, arg, v, nv); 3997 } 3998 3999 /* 4000 * Create a constant node for sizeof. 4001 */ 4002 tnode_t * 4003 build_sizeof(const type_t *tp) 4004 { 4005 unsigned int size_in_bytes = type_size_in_bits(tp) / CHAR_SIZE; 4006 tnode_t *tn = build_integer_constant(SIZEOF_TSPEC, size_in_bytes); 4007 tn->tn_system_dependent = true; 4008 debug_step("build_sizeof '%s' = %u", type_name(tp), size_in_bytes); 4009 return tn; 4010 } 4011 4012 /* 4013 * Create a constant node for offsetof. 4014 */ 4015 tnode_t * 4016 build_offsetof(const type_t *tp, const sym_t *sym) 4017 { 4018 unsigned int offset_in_bits = 0; 4019 4020 if (!is_struct_or_union(tp->t_tspec)) { 4021 /* unacceptable operand of '%s' */ 4022 error(111, "offsetof"); 4023 goto proceed; 4024 } 4025 sym_t *mem = find_member(tp->t_sou, sym->s_name); 4026 if (mem == NULL) { 4027 /* type '%s' does not have member '%s' */ 4028 error(101, sym->s_name, type_name(tp)); 4029 goto proceed; 4030 } 4031 offset_in_bits = mem->u.s_member.sm_offset_in_bits; 4032 4033 proceed:; 4034 unsigned int offset_in_bytes = offset_in_bits / CHAR_SIZE; 4035 tnode_t *tn = build_integer_constant(SIZEOF_TSPEC, offset_in_bytes); 4036 tn->tn_system_dependent = true; 4037 return tn; 4038 } 4039 4040 unsigned int 4041 type_size_in_bits(const type_t *tp) 4042 { 4043 4044 unsigned int elem = 1; 4045 bool flex = false; 4046 lint_assert(tp != NULL); 4047 while (tp->t_tspec == ARRAY) { 4048 flex = true; /* allow c99 flex arrays [] [0] */ 4049 elem *= tp->t_dim; 4050 tp = tp->t_subt; 4051 } 4052 if (elem == 0 && !flex) { 4053 /* cannot take size/alignment of incomplete type */ 4054 error(143); 4055 elem = 1; 4056 } 4057 4058 unsigned int elsz; 4059 switch (tp->t_tspec) { 4060 case VOID: 4061 /* cannot take size/alignment of void */ 4062 error(146); 4063 elsz = 1; 4064 break; 4065 case FUNC: 4066 /* cannot take size/alignment of function type '%s' */ 4067 error(144, type_name(tp)); 4068 elsz = 1; 4069 break; 4070 case STRUCT: 4071 case UNION: 4072 if (is_incomplete(tp)) { 4073 /* cannot take size/alignment of incomplete type */ 4074 error(143); 4075 elsz = 1; 4076 } else { 4077 elsz = tp->t_sou->sou_size_in_bits; 4078 } 4079 break; 4080 case ENUM: 4081 if (is_incomplete(tp)) { 4082 /* cannot take size/alignment of incomplete type */ 4083 warning(143); 4084 } 4085 /* FALLTHROUGH */ 4086 default: 4087 if (tp->t_bitfield) { 4088 /* cannot take size/alignment of bit-field */ 4089 error(145); 4090 } 4091 elsz = size_in_bits(tp->t_tspec); 4092 lint_assert(elsz > 0); 4093 break; 4094 } 4095 4096 return elem * elsz; 4097 } 4098 4099 /* C11 6.5.3.4, GCC */ 4100 tnode_t * 4101 build_alignof(const type_t *tp) 4102 { 4103 if (tp->t_tspec == FUNC) { 4104 /* cannot take size/alignment of function type '%s' */ 4105 error(144, type_name(tp)); 4106 return NULL; 4107 } 4108 if (tp->t_tspec == VOID) { 4109 /* cannot take size/alignment of void */ 4110 error(146); 4111 return NULL; 4112 } 4113 if (is_incomplete(tp)) { 4114 /* cannot take size/alignment of incomplete type */ 4115 error(143); 4116 return NULL; 4117 } 4118 if (tp->t_bitfield) { 4119 /* cannot take size/alignment of bit-field */ 4120 error(145); 4121 return NULL; 4122 } 4123 return build_integer_constant(SIZEOF_TSPEC, 4124 (int64_t)alignment_in_bits(tp) / CHAR_SIZE); 4125 } 4126 4127 static tnode_t * 4128 cast_to_union(tnode_t *otn, type_t *ntp) 4129 { 4130 4131 if (!allow_gcc) { 4132 /* union cast is a GCC extension */ 4133 error(328); 4134 return NULL; 4135 } 4136 4137 for (const sym_t *m = ntp->t_sou->sou_first_member; 4138 m != NULL; m = m->s_next) { 4139 if (types_compatible(m->s_type, otn->tn_type, 4140 false, false, NULL)) { 4141 tnode_t *ntn = expr_alloc_tnode(); 4142 ntn->tn_op = CVT; 4143 ntn->tn_type = ntp; 4144 ntn->tn_cast = true; 4145 ntn->tn_left = otn; 4146 ntn->tn_right = NULL; 4147 return ntn; 4148 } 4149 } 4150 4151 /* type '%s' is not a member of '%s' */ 4152 error(329, type_name(otn->tn_type), type_name(ntp)); 4153 return NULL; 4154 } 4155 4156 /* 4157 * Type casts. 4158 */ 4159 tnode_t * 4160 cast(tnode_t *tn, type_t *tp) 4161 { 4162 4163 if (tn == NULL) 4164 return NULL; 4165 4166 tn = cconv(tn); 4167 4168 lint_assert(tp != NULL); 4169 tspec_t nt = tp->t_tspec; 4170 tspec_t ot = tn->tn_type->t_tspec; 4171 4172 if (nt == VOID) { 4173 /* 4174 * C90 6.3.4, C99 6.5.4p2 and C11 6.5.4p2 allow any type to 4175 * be cast to void. The only other allowed casts are from a 4176 * scalar type to a scalar type. 4177 */ 4178 } else if (nt == UNION) 4179 return cast_to_union(tn, tp); 4180 else if (nt == STRUCT || nt == ARRAY || nt == FUNC) { 4181 /* Casting to a struct is an undocumented GCC extension. */ 4182 if (!(allow_gcc && nt == STRUCT)) 4183 goto invalid_cast; 4184 } else if (is_struct_or_union(ot)) 4185 goto invalid_cast; 4186 else if (ot == VOID) { 4187 /* improper cast of void expression */ 4188 error(148); 4189 return NULL; 4190 } else if (is_integer(nt) && is_scalar(ot)) { 4191 /* ok */ 4192 } else if (is_floating(nt) && is_arithmetic(ot)) { 4193 /* ok */ 4194 } else if (nt == PTR && is_integer(ot)) { 4195 /* ok */ 4196 } else if (nt == PTR && ot == PTR) { 4197 if (!tp->t_subt->t_const && tn->tn_type->t_subt->t_const) { 4198 if (hflag) 4199 /* cast discards 'const' from type '%s' */ 4200 warning(275, type_name(tn->tn_type)); 4201 } 4202 } else 4203 goto invalid_cast; 4204 4205 if (any_query_enabled && types_compatible(tp, tn->tn_type, 4206 false, false, NULL)) { 4207 /* no-op cast from '%s' to '%s' */ 4208 query_message(6, type_name(tn->tn_type), type_name(tp)); 4209 } 4210 4211 tn = convert(CVT, 0, tp, tn); 4212 tn->tn_cast = true; 4213 4214 return tn; 4215 4216 invalid_cast: 4217 /* invalid cast from '%s' to '%s' */ 4218 error(147, type_name(tn->tn_type), type_name(tp)); 4219 return NULL; 4220 } 4221 4222 /* 4223 * Create the node for a function argument. 4224 * All necessary conversions and type checks are done in 4225 * build_function_call because build_function_argument has no 4226 * information about the expected parameter types. 4227 */ 4228 tnode_t * 4229 build_function_argument(tnode_t *args, tnode_t *arg) 4230 { 4231 /* 4232 * If there was a serious error in the expression for the argument, 4233 * create a dummy argument so the positions of the remaining arguments 4234 * will not change. 4235 */ 4236 if (arg == NULL) 4237 arg = build_integer_constant(INT, 0); 4238 4239 return build_op(PUSH, arg->tn_sys, arg->tn_type, arg, args); 4240 } 4241 4242 /* 4243 * Compare the type of an argument with the corresponding type of a 4244 * prototype parameter. If it is a valid combination, but both types 4245 * are not the same, insert a conversion to convert the argument into 4246 * the type of the parameter. 4247 */ 4248 static tnode_t * 4249 check_prototype_argument( 4250 int n, /* pos of arg */ 4251 type_t *tp, /* expected type (from prototype) */ 4252 tnode_t *tn) /* argument */ 4253 { 4254 tnode_t *ln = xcalloc(1, sizeof(*ln)); 4255 ln->tn_type = expr_unqualified_type(tp); 4256 ln->tn_lvalue = true; 4257 if (typeok(FARG, n, ln, tn)) { 4258 bool dowarn; 4259 if (!types_compatible(tp, tn->tn_type, 4260 true, false, (dowarn = false, &dowarn)) || dowarn) 4261 tn = convert(FARG, n, tp, tn); 4262 } 4263 free(ln); 4264 return tn; 4265 } 4266 4267 /* 4268 * Check types of all function arguments and insert conversions, 4269 * if necessary. 4270 */ 4271 static tnode_t * 4272 check_function_arguments(type_t *ftp, tnode_t *args) 4273 { 4274 /* get # of parameters in the prototype */ 4275 int npar = 0; 4276 for (const sym_t *p = ftp->t_params; p != NULL; p = p->s_next) 4277 npar++; 4278 4279 /* get # of arguments in the function call */ 4280 int narg = 0; 4281 for (const tnode_t *arg = args; arg != NULL; arg = tn_ck_right(arg)) 4282 narg++; 4283 4284 const sym_t *param = ftp->t_params; 4285 if (ftp->t_proto && npar != narg && !(ftp->t_vararg && npar < narg)) { 4286 /* argument mismatch: %d %s passed, %d expected */ 4287 error(150, narg, narg != 1 ? "arguments" : "argument", npar); 4288 param = NULL; 4289 } 4290 4291 for (int n = 1; n <= narg; n++) { 4292 4293 // The rightmost argument starts the argument list. 4294 tnode_t *arg = args; 4295 for (int i = narg; i > n; i--, arg = arg->tn_right) 4296 continue; 4297 4298 /* some things which are always not allowed */ 4299 tspec_t at = arg->tn_left->tn_type->t_tspec; 4300 if (at == VOID) { 4301 /* void expressions may not be arguments, arg #%d */ 4302 error(151, n); 4303 return NULL; 4304 } 4305 if (is_struct_or_union(at) && 4306 is_incomplete(arg->tn_left->tn_type)) { 4307 /* argument cannot have unknown size, arg #%d */ 4308 error(152, n); 4309 return NULL; 4310 } 4311 if (is_integer(at) && 4312 arg->tn_left->tn_type->t_is_enum && 4313 is_incomplete(arg->tn_left->tn_type)) { 4314 /* argument cannot have unknown size, arg #%d */ 4315 warning(152, n); 4316 } 4317 4318 /* class conversions (arg in value context) */ 4319 arg->tn_left = cconv(arg->tn_left); 4320 4321 if (param != NULL) { 4322 arg->tn_left = check_prototype_argument( 4323 n, param->s_type, arg->tn_left); 4324 } else 4325 arg->tn_left = promote(NOOP, true, arg->tn_left); 4326 arg->tn_type = arg->tn_left->tn_type; 4327 4328 if (param != NULL) 4329 param = param->s_next; 4330 } 4331 4332 return args; 4333 } 4334 4335 /* 4336 * Create the node for a function call. Also check types of 4337 * function arguments and insert conversions, if necessary. 4338 */ 4339 tnode_t * 4340 build_function_call(tnode_t *func, bool sys, tnode_t *args) 4341 { 4342 4343 if (func == NULL) 4344 return NULL; 4345 4346 op_t fcop = func->tn_op == NAME && func->tn_type->t_tspec == FUNC 4347 ? CALL : ICALL; 4348 4349 check_ctype_function_call(func, args); 4350 4351 /* Turn the function name into a pointer to the function. */ 4352 func = cconv(func); 4353 4354 if (func->tn_type->t_tspec != PTR || 4355 func->tn_type->t_subt->t_tspec != FUNC) { 4356 /* cannot call '%s', must be a function */ 4357 error(149, type_name(func->tn_type)); 4358 return NULL; 4359 } 4360 4361 args = check_function_arguments(func->tn_type->t_subt, args); 4362 4363 return build_op(fcop, sys, func->tn_type->t_subt->t_subt, func, args); 4364 } 4365 4366 /* 4367 * Return the value of an integral constant expression. 4368 * If the expression is not constant or its type is not an integer 4369 * type, an error message is printed. 4370 */ 4371 val_t * 4372 integer_constant(tnode_t *tn, bool required) 4373 { 4374 4375 if (tn != NULL) 4376 tn = cconv(tn); 4377 if (tn != NULL) 4378 tn = promote(NOOP, false, tn); 4379 4380 val_t *v = xcalloc(1, sizeof(*v)); 4381 4382 if (tn == NULL) { 4383 lint_assert(seen_error); 4384 debug_step("constant node is null; returning 1 instead"); 4385 v->v_tspec = INT; 4386 v->u.integer = 1; 4387 return v; 4388 } 4389 4390 v->v_tspec = tn->tn_type->t_tspec; 4391 4392 if (tn->tn_op == CON) { 4393 lint_assert(tn->tn_type->t_tspec == tn->tn_val.v_tspec); 4394 if (is_integer(tn->tn_val.v_tspec)) { 4395 v->v_unsigned_since_c90 = 4396 tn->tn_val.v_unsigned_since_c90; 4397 v->u.integer = tn->tn_val.u.integer; 4398 return v; 4399 } 4400 v->u.integer = (int64_t)tn->tn_val.u.floating; 4401 } else { 4402 v->u.integer = 1; 4403 } 4404 4405 if (required) 4406 /* integral constant expression expected */ 4407 error(55); 4408 else 4409 /* variable array dimension is a C99/GCC extension */ 4410 c99ism(318); 4411 4412 if (!is_integer(v->v_tspec)) 4413 v->v_tspec = INT; 4414 4415 return v; 4416 } 4417 4418 static bool 4419 is_constcond_false(const tnode_t *tn, tspec_t t) 4420 { 4421 return (t == BOOL || t == INT) && 4422 tn->tn_op == CON && tn->tn_val.u.integer == 0; 4423 } 4424 4425 /* 4426 * Perform some tests on expressions which can't be done in build_binary() 4427 * and functions called by build_binary(). These tests must be done here 4428 * because we need some information about the context in which the operations 4429 * are performed. 4430 * After all tests are performed and dofreeblk is true, expr() frees the 4431 * memory which is used for the expression. 4432 */ 4433 void 4434 expr(tnode_t *tn, bool vctx, bool cond, bool dofreeblk, bool is_do_while) 4435 { 4436 4437 if (tn == NULL) { /* in case of errors */ 4438 expr_free_all(); 4439 return; 4440 } 4441 4442 /* expr() is also called in global initializations */ 4443 if (dcs->d_kind != DLK_EXTERN && !is_do_while) 4444 check_statement_reachable(); 4445 4446 check_expr_misc(tn, vctx, cond, !cond, false, false, false); 4447 if (tn->tn_op == ASSIGN && !tn->tn_parenthesized) { 4448 if (hflag && cond) 4449 /* assignment in conditional context */ 4450 warning(159); 4451 } else if (tn->tn_op == CON) { 4452 if (hflag && cond && !suppress_constcond && 4453 !tn->tn_system_dependent && 4454 !(is_do_while && 4455 is_constcond_false(tn, tn->tn_type->t_tspec))) 4456 /* constant in conditional context */ 4457 warning(161); 4458 } 4459 if (!modtab[tn->tn_op].m_has_side_effect) { 4460 /* 4461 * for left operands of COMMA this warning is already 4462 * printed 4463 */ 4464 if (tn->tn_op != COMMA && !vctx && !cond) 4465 check_null_effect(tn); 4466 } 4467 debug_node(tn); 4468 4469 /* free the tree memory */ 4470 if (dofreeblk) 4471 expr_free_all(); 4472 } 4473 4474 /* 4475 * Checks the range of array indices, if possible. 4476 * amper is set if only the address of the element is used. This 4477 * means that the index is allowed to refer to the first element 4478 * after the array. 4479 */ 4480 static void 4481 check_array_index(tnode_t *tn, bool amper) 4482 { 4483 lint_assert(has_operands(tn)); 4484 const tnode_t *ln = tn->tn_left; 4485 const tnode_t *rn = tn->tn_right; 4486 4487 /* We can only check constant indices. */ 4488 if (rn->tn_op != CON) 4489 return; 4490 4491 /* Return if the left node does not stem from an array. */ 4492 if (ln->tn_op != ADDR) 4493 return; 4494 if (ln->tn_left->tn_op != STRING && ln->tn_left->tn_op != NAME) 4495 return; 4496 if (ln->tn_left->tn_type->t_tspec != ARRAY) 4497 return; 4498 4499 /* 4500 * For incomplete array types, we can print a warning only if 4501 * the index is negative. 4502 */ 4503 if (is_incomplete(ln->tn_left->tn_type) && rn->tn_val.u.integer >= 0) 4504 return; 4505 4506 /* Get the size of one array element */ 4507 int elsz = length_in_bits(ln->tn_type->t_subt, NULL); 4508 if (elsz == 0) 4509 return; 4510 elsz /= CHAR_SIZE; 4511 4512 /* Change the unit of the index from bytes to element size. */ 4513 int64_t con = is_uinteger(rn->tn_type->t_tspec) 4514 ? (int64_t)((uint64_t)rn->tn_val.u.integer / elsz) 4515 : rn->tn_val.u.integer / elsz; 4516 4517 int dim = ln->tn_left->tn_type->t_dim + (amper ? 1 : 0); 4518 4519 if (!is_uinteger(rn->tn_type->t_tspec) && con < 0) { 4520 /* array subscript cannot be negative: %ld */ 4521 warning(167, (long)con); 4522 } else if (dim > 0 && (uint64_t)con >= (uint64_t)dim) { 4523 /* array subscript cannot be > %d: %ld */ 4524 warning(168, dim - 1, (long)con); 4525 } 4526 } 4527 4528 static void 4529 check_expr_addr(const tnode_t *ln, bool szof, bool fcall) 4530 { 4531 /* XXX: Taking warn_about_unreachable into account here feels wrong. */ 4532 if (ln->tn_op == NAME && (reached || !warn_about_unreachable)) { 4533 if (!szof) 4534 mark_as_set(ln->tn_sym); 4535 mark_as_used(ln->tn_sym, fcall, szof); 4536 } 4537 if (ln->tn_op == INDIR && ln->tn_left->tn_op == PLUS) 4538 /* check the range of array indices */ 4539 check_array_index(ln->tn_left, true); 4540 } 4541 4542 static void 4543 check_expr_load(const tnode_t *ln) 4544 { 4545 if (ln->tn_op == INDIR && ln->tn_left->tn_op == PLUS) 4546 /* check the range of array indices */ 4547 check_array_index(ln->tn_left, false); 4548 } 4549 4550 /* 4551 * If there is an asm statement in one of the compound statements around, 4552 * there may be other side effects, so don't warn. 4553 */ 4554 static bool 4555 is_asm_around(void) 4556 { 4557 for (decl_level *dl = dcs; dl != NULL; dl = dl->d_enclosing) 4558 if (dl->d_asm) 4559 return true; 4560 return false; 4561 } 4562 4563 static void 4564 check_expr_side_effect(const tnode_t *ln, bool szof) 4565 { 4566 4567 /* XXX: Taking warn_about_unreachable into account here feels wrong. */ 4568 if (ln->tn_op == NAME && (reached || !warn_about_unreachable)) { 4569 scl_t sc = ln->tn_sym->s_scl; 4570 if (sc != EXTERN && sc != STATIC && 4571 !ln->tn_sym->s_set && !szof && !is_asm_around()) { 4572 /* '%s' may be used before set */ 4573 warning(158, ln->tn_sym->s_name); 4574 mark_as_set(ln->tn_sym); 4575 } 4576 mark_as_used(ln->tn_sym, false, false); 4577 } 4578 } 4579 4580 static void 4581 check_expr_assign(const tnode_t *ln, bool szof) 4582 { 4583 /* XXX: Taking warn_about_unreachable into account here feels wrong. */ 4584 if (ln->tn_op == NAME && !szof && (reached || !warn_about_unreachable)) { 4585 mark_as_set(ln->tn_sym); 4586 if (ln->tn_sym->s_scl == EXTERN) 4587 outusg(ln->tn_sym); 4588 } 4589 if (ln->tn_op == INDIR && ln->tn_left->tn_op == PLUS) 4590 /* check the range of array indices */ 4591 check_array_index(ln->tn_left, false); 4592 } 4593 4594 static void 4595 check_expr_call(const tnode_t *tn, const tnode_t *ln, 4596 bool szof, bool vctx, bool cond, bool retval_discarded) 4597 { 4598 lint_assert(ln->tn_op == ADDR); 4599 lint_assert(ln->tn_left->tn_op == NAME); 4600 if (!szof && !is_compiler_builtin(ln->tn_left->tn_sym->s_name)) 4601 outcall(tn, vctx || cond, retval_discarded); 4602 } 4603 4604 static void 4605 check_expr_op(const tnode_t *tn, op_t op, const tnode_t *ln, 4606 bool szof, bool fcall, bool vctx, bool cond, 4607 bool retval_discarded, bool eqwarn) 4608 { 4609 switch (op) { 4610 case ADDR: 4611 check_expr_addr(ln, szof, fcall); 4612 break; 4613 case LOAD: 4614 check_expr_load(ln); 4615 /* FALLTHROUGH */ 4616 case PUSH: 4617 case INCBEF: 4618 case DECBEF: 4619 case INCAFT: 4620 case DECAFT: 4621 case ADDASS: 4622 case SUBASS: 4623 case MULASS: 4624 case DIVASS: 4625 case MODASS: 4626 case ANDASS: 4627 case ORASS: 4628 case XORASS: 4629 case SHLASS: 4630 case SHRASS: 4631 case REAL: 4632 case IMAG: 4633 check_expr_side_effect(ln, szof); 4634 break; 4635 case ASSIGN: 4636 check_expr_assign(ln, szof); 4637 break; 4638 case CALL: 4639 check_expr_call(tn, ln, szof, vctx, cond, retval_discarded); 4640 break; 4641 case EQ: 4642 if (hflag && eqwarn) 4643 /* operator '==' found where '=' was expected */ 4644 warning(160); 4645 break; 4646 default: 4647 break; 4648 } 4649 } 4650 4651 /* 4652 * vctx ??? 4653 * cond whether the expression is a condition that 4654 * will be compared with 0 4655 * eqwarn whether the operator '==' might be a 4656 * misspelled '=' 4657 * fcall whether the expression is a function call 4658 * retval_discarded whether the return value of a function call 4659 * is discarded; such calls will be analyzed by 4660 * lint2 in messages 4, 8 and 9 4661 * szof whether the expression is part of a sizeof 4662 * expression, which means that its value is 4663 * discarded since only the type is relevant 4664 */ 4665 void 4666 check_expr_misc(const tnode_t *tn, bool vctx, bool cond, 4667 bool eqwarn, bool fcall, bool retval_discarded, bool szof) 4668 { 4669 4670 if (tn == NULL) 4671 return; 4672 op_t op = tn->tn_op; 4673 if (op == NAME || op == CON || op == STRING) 4674 return; 4675 4676 lint_assert(has_operands(tn)); 4677 tnode_t *ln = tn->tn_left; 4678 tnode_t *rn = tn->tn_right; 4679 check_expr_op(tn, op, ln, 4680 szof, fcall, vctx, cond, retval_discarded, eqwarn); 4681 4682 const mod_t *mp = &modtab[op]; 4683 bool cvctx = mp->m_value_context; 4684 bool ccond = mp->m_compares_with_zero; 4685 bool eq = mp->m_warn_if_operand_eq && 4686 !ln->tn_parenthesized && 4687 rn != NULL && !rn->tn_parenthesized; 4688 4689 /* 4690 * values of operands of ':' are not used if the type of at least 4691 * one of the operands (for gcc compatibility) is void 4692 * XXX test/value context of QUEST should probably be used as 4693 * context for both operands of COLON 4694 */ 4695 if (op == COLON && tn->tn_type->t_tspec == VOID) 4696 cvctx = ccond = false; 4697 bool discard = op == CVT && tn->tn_type->t_tspec == VOID; 4698 check_expr_misc(ln, cvctx, ccond, eq, op == CALL, discard, szof); 4699 4700 switch (op) { 4701 case PUSH: 4702 if (rn != NULL) 4703 check_expr_misc(rn, false, false, eq, false, false, 4704 szof); 4705 break; 4706 case LOGAND: 4707 case LOGOR: 4708 check_expr_misc(rn, false, true, eq, false, false, szof); 4709 break; 4710 case COLON: 4711 check_expr_misc(rn, cvctx, ccond, eq, false, false, szof); 4712 break; 4713 case COMMA: 4714 check_expr_misc(rn, vctx, cond, false, false, false, szof); 4715 break; 4716 default: 4717 if (mp->m_binary) 4718 check_expr_misc(rn, true, false, eq, false, false, 4719 szof); 4720 break; 4721 } 4722 } 4723 4724 /* 4725 * Return whether the expression can be used for static initialization. 4726 * 4727 * Constant initialization expressions must be constant or an address 4728 * of a static object with an optional offset. In the first case, 4729 * the result is returned in *offsp. In the second case, the static 4730 * object is returned in *symp and the offset in *offsp. 4731 * 4732 * The expression can consist of PLUS, MINUS, ADDR, NAME, STRING and 4733 * CON. Type conversions are allowed if they do not change binary 4734 * representation (including width). 4735 * 4736 * C99 6.6 "Constant expressions" 4737 * C99 6.7.8p4 restricts initializers for static storage duration 4738 */ 4739 bool 4740 constant_addr(const tnode_t *tn, const sym_t **symp, ptrdiff_t *offsp) 4741 { 4742 const sym_t *sym; 4743 ptrdiff_t offs1, offs2; 4744 tspec_t t, ot; 4745 4746 switch (tn->tn_op) { 4747 case MINUS: 4748 if (tn->tn_right->tn_op == CVT) 4749 return constant_addr(tn->tn_right, symp, offsp); 4750 else if (tn->tn_right->tn_op != CON) 4751 return false; 4752 /* FALLTHROUGH */ 4753 case PLUS: 4754 offs1 = offs2 = 0; 4755 if (tn->tn_left->tn_op == CON) { 4756 offs1 = (ptrdiff_t)tn->tn_left->tn_val.u.integer; 4757 if (!constant_addr(tn->tn_right, &sym, &offs2)) 4758 return false; 4759 } else if (tn->tn_right->tn_op == CON) { 4760 offs2 = (ptrdiff_t)tn->tn_right->tn_val.u.integer; 4761 if (tn->tn_op == MINUS) 4762 offs2 = -offs2; 4763 if (!constant_addr(tn->tn_left, &sym, &offs1)) 4764 return false; 4765 } else { 4766 return false; 4767 } 4768 *symp = sym; 4769 *offsp = offs1 + offs2; 4770 return true; 4771 case ADDR: 4772 if (tn->tn_left->tn_op == NAME) { 4773 *symp = tn->tn_left->tn_sym; 4774 *offsp = 0; 4775 return true; 4776 } else { 4777 /* 4778 * If this were the front end of a compiler, we 4779 * would return a label instead of 0, at least if 4780 * 'tn->tn_left->tn_op == STRING'. 4781 */ 4782 *symp = NULL; 4783 *offsp = 0; 4784 return true; 4785 } 4786 case CVT: 4787 t = tn->tn_type->t_tspec; 4788 ot = tn->tn_left->tn_type->t_tspec; 4789 if ((!is_integer(t) && t != PTR) || 4790 (!is_integer(ot) && ot != PTR)) { 4791 return false; 4792 } 4793 #if 0 4794 /* 4795 * consider: 4796 * struct foo { 4797 * unsigned char a; 4798 * } f = { 4799 * (unsigned char)(unsigned long) 4800 * (&(((struct foo *)0)->a)) 4801 * }; 4802 * since psize(unsigned long) != psize(unsigned char), 4803 * this fails. 4804 */ 4805 else if (psize(t) != psize(ot)) 4806 return -1; 4807 #endif 4808 return constant_addr(tn->tn_left, symp, offsp); 4809 default: 4810 return false; 4811 } 4812 } 4813 4814 /* Append s2 to s1, then free s2. */ 4815 strg_t * 4816 cat_strings(strg_t *s1, strg_t *s2) 4817 { 4818 4819 if (s1->st_char != s2->st_char) { 4820 /* cannot concatenate wide and regular string literals */ 4821 error(292); 4822 return s1; 4823 } 4824 4825 size_t len1 = s1->st_len; 4826 size_t len2 = s2->st_len; 4827 size_t chsize = s1->st_char ? sizeof(char) : sizeof(wchar_t); 4828 size_t size1 = len1 * chsize; 4829 size_t size2 = (len2 + 1) * chsize; 4830 s1->st_mem = xrealloc(s1->st_mem, size1 + size2); 4831 memcpy((char *)s1->st_mem + size1, s2->st_mem, size2); 4832 free(s2->st_mem); 4833 4834 s1->st_len = len1 + len2; 4835 free(s2); 4836 4837 return s1; 4838 } 4839 4840 4841 typedef struct stmt_expr { 4842 memory_pool se_mem; 4843 sym_t *se_sym; 4844 struct stmt_expr *se_enclosing; 4845 } stmt_expr; 4846 4847 static stmt_expr *stmt_exprs; 4848 4849 void 4850 begin_statement_expr(void) 4851 { 4852 debug_enter(); 4853 4854 stmt_expr *se = xmalloc(sizeof(*se)); 4855 se->se_mem = expr_save_memory(); 4856 se->se_sym = NULL; 4857 se->se_enclosing = stmt_exprs; 4858 stmt_exprs = se; 4859 } 4860 4861 void 4862 do_statement_expr(tnode_t *tn) 4863 { 4864 block_level--; 4865 mem_block_level--; 4866 stmt_exprs->se_sym = tn != NULL 4867 ? mktempsym(block_dup_type(tn->tn_type)) 4868 : NULL; /* after a syntax error */ 4869 mem_block_level++; 4870 block_level++; 4871 /* '({ ... })' is a GCC extension */ 4872 gnuism(320); 4873 } 4874 4875 tnode_t * 4876 end_statement_expr(void) 4877 { 4878 tnode_t *tn; 4879 4880 stmt_expr *se = stmt_exprs; 4881 if (se->se_sym == NULL) { 4882 tn = NULL; /* after a syntax error */ 4883 goto end; 4884 } 4885 4886 tn = build_name(se->se_sym, false); 4887 (void)expr_save_memory(); /* leak */ 4888 expr_restore_memory(se->se_mem); 4889 stmt_exprs = se->se_enclosing; 4890 free(se); 4891 4892 end: 4893 debug_leave(); 4894 return tn; 4895 } 4896 4897 bool 4898 in_statement_expr(void) 4899 { 4900 return stmt_exprs != NULL; 4901 } 4902
Indexes created Wed Sep 24 05:09:52 GMT 2025