tree.c revision 1.586
1 /* $NetBSD: tree.c,v 1.586 2023/12/03 13:12:40 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 1.586 2023/12/03 13:12:40 rillig Exp $"); 41 #endif 42 43 #include <float.h> 44 #include <limits.h> 45 #include <math.h> 46 #include <signal.h> 47 #include <stdlib.h> 48 #include <string.h> 49 50 #include "lint1.h" 51 52 53 typedef struct integer_constraints { 54 int64_t smin; /* signed minimum */ 55 int64_t smax; /* signed maximum */ 56 uint64_t umin; /* unsigned minimum */ 57 uint64_t umax; /* unsigned maximum */ 58 uint64_t bset; /* bits that are definitely set */ 59 uint64_t bclr; /* bits that are definitely clear */ 60 } integer_constraints; 61 62 63 static uint64_t 64 u64_fill_right(uint64_t x) 65 { 66 x |= x >> 1; 67 x |= x >> 2; 68 x |= x >> 4; 69 x |= x >> 8; 70 x |= x >> 16; 71 x |= x >> 32; 72 return x; 73 } 74 75 static bool 76 str_ends_with(const char *haystack, const char *needle) 77 { 78 size_t hlen = strlen(haystack); 79 size_t nlen = strlen(needle); 80 81 return nlen <= hlen && 82 memcmp(haystack + hlen - nlen, needle, nlen) == 0; 83 } 84 85 static unsigned 86 width_in_bits(const type_t *tp) 87 { 88 89 lint_assert(is_integer(tp->t_tspec)); 90 return tp->t_bitfield 91 ? tp->t_bit_field_width 92 : size_in_bits(tp->t_tspec); 93 } 94 95 static int 96 portable_rank_cmp(tspec_t t1, tspec_t t2) 97 { 98 const ttab_t *p1 = type_properties(t1), *p2 = type_properties(t2); 99 lint_assert(p1->tt_rank_kind == p2->tt_rank_kind); 100 lint_assert(p1->tt_rank_value > 0); 101 lint_assert(p2->tt_rank_value > 0); 102 return (int)p1->tt_rank_value - (int)p2->tt_rank_value; 103 } 104 105 static bool 106 ic_maybe_signed(const type_t *tp, const integer_constraints *ic) 107 { 108 return !is_uinteger(tp->t_tspec) && ic->bclr >> 63 == 0; 109 } 110 111 static integer_constraints 112 ic_any(const type_t *tp) 113 { 114 integer_constraints c; 115 116 uint64_t vbits = value_bits(width_in_bits(tp)); 117 if (is_uinteger(tp->t_tspec)) { 118 c.smin = INT64_MIN; 119 c.smax = INT64_MAX; 120 c.umin = 0; 121 c.umax = vbits; 122 c.bset = 0; 123 c.bclr = ~c.umax; 124 } else { 125 c.smin = (int64_t)-1 - (int64_t)(vbits >> 1); 126 c.smax = (int64_t)(vbits >> 1); 127 c.umin = 0; 128 c.umax = UINT64_MAX; 129 c.bset = 0; 130 c.bclr = 0; 131 } 132 return c; 133 } 134 135 static integer_constraints 136 ic_con(const type_t *tp, const val_t *v) 137 { 138 integer_constraints c; 139 140 lint_assert(is_integer(tp->t_tspec)); 141 int64_t si = v->u.integer; 142 uint64_t ui = (uint64_t)si; 143 c.smin = si; 144 c.smax = si; 145 c.umin = ui; 146 c.umax = ui; 147 c.bset = ui; 148 c.bclr = ~ui; 149 return c; 150 } 151 152 static integer_constraints 153 ic_cvt(const type_t *ntp, const type_t *otp, integer_constraints a) 154 { 155 unsigned nw = width_in_bits(ntp); 156 unsigned ow = width_in_bits(otp); 157 bool nu = is_uinteger(ntp->t_tspec); 158 bool ou = is_uinteger(otp->t_tspec); 159 160 if (nw >= ow && nu == ou) 161 return a; 162 if (nw > ow && ou) 163 return a; 164 return ic_any(ntp); 165 } 166 167 static integer_constraints 168 ic_bitand(integer_constraints a, integer_constraints b) 169 { 170 integer_constraints c; 171 172 c.smin = INT64_MIN; 173 c.smax = INT64_MAX; 174 c.umin = 0; 175 c.umax = UINT64_MAX; 176 c.bset = a.bset & b.bset; 177 c.bclr = a.bclr | b.bclr; 178 return c; 179 } 180 181 static integer_constraints 182 ic_bitor(integer_constraints a, integer_constraints b) 183 { 184 integer_constraints c; 185 186 c.smin = INT64_MIN; 187 c.smax = INT64_MAX; 188 c.umin = 0; 189 c.umax = UINT64_MAX; 190 c.bset = a.bset | b.bset; 191 c.bclr = a.bclr & b.bclr; 192 return c; 193 } 194 195 static integer_constraints 196 ic_mod(const type_t *tp, integer_constraints a, integer_constraints b) 197 { 198 integer_constraints c; 199 200 if (ic_maybe_signed(tp, &a) || ic_maybe_signed(tp, &b)) 201 return ic_any(tp); 202 203 c.smin = INT64_MIN; 204 c.smax = INT64_MAX; 205 c.umin = 0; 206 c.umax = b.umax - 1; 207 c.bset = 0; 208 c.bclr = ~u64_fill_right(c.umax); 209 return c; 210 } 211 212 static integer_constraints 213 ic_shl(const type_t *tp, integer_constraints a, integer_constraints b) 214 { 215 integer_constraints c; 216 unsigned int amount; 217 218 if (ic_maybe_signed(tp, &a)) 219 return ic_any(tp); 220 221 if (b.smin == b.smax && b.smin >= 0 && b.smin < 64) 222 amount = (unsigned int)b.smin; 223 else if (b.umin == b.umax && b.umin < 64) 224 amount = (unsigned int)b.umin; 225 else 226 return ic_any(tp); 227 228 c.smin = INT64_MIN; 229 c.smax = INT64_MAX; 230 c.umin = 0; 231 c.umax = UINT64_MAX; 232 c.bset = a.bset << amount; 233 c.bclr = a.bclr << amount | (((uint64_t)1 << amount) - 1); 234 return c; 235 } 236 237 static integer_constraints 238 ic_shr(const type_t *tp, integer_constraints a, integer_constraints b) 239 { 240 integer_constraints c; 241 unsigned int amount; 242 243 if (ic_maybe_signed(tp, &a)) 244 return ic_any(tp); 245 246 if (b.smin == b.smax && b.smin >= 0 && b.smin < 64) 247 amount = (unsigned int)b.smin; 248 else if (b.umin == b.umax && b.umin < 64) 249 amount = (unsigned int)b.umin; 250 else 251 return ic_any(tp); 252 253 c.smin = INT64_MIN; 254 c.smax = INT64_MAX; 255 c.umin = 0; 256 c.umax = UINT64_MAX; 257 c.bset = a.bset >> amount; 258 c.bclr = a.bclr >> amount | ~(~(uint64_t)0 >> amount); 259 return c; 260 } 261 262 static integer_constraints 263 ic_cond(integer_constraints a, integer_constraints b) 264 { 265 integer_constraints c; 266 267 c.smin = a.smin < b.smin ? a.smin : b.smin; 268 c.smax = a.smax > b.smax ? a.smax : b.smax; 269 c.umin = a.umin < b.umin ? a.umin : b.umin; 270 c.umax = a.umax > b.umax ? a.umax : b.umax; 271 c.bset = a.bset | b.bset; 272 c.bclr = a.bclr & b.bclr; 273 return c; 274 } 275 276 static integer_constraints 277 ic_expr(const tnode_t *tn) 278 { 279 integer_constraints lc, rc; 280 281 lint_assert(is_integer(tn->tn_type->t_tspec)); 282 283 switch (tn->tn_op) { 284 case CON: 285 return ic_con(tn->tn_type, &tn->tn_val); 286 case CVT: 287 if (!is_integer(tn->tn_left->tn_type->t_tspec)) 288 return ic_any(tn->tn_type); 289 lc = ic_expr(tn->tn_left); 290 return ic_cvt(tn->tn_type, tn->tn_left->tn_type, lc); 291 case MOD: 292 lc = ic_expr(before_conversion(tn->tn_left)); 293 rc = ic_expr(before_conversion(tn->tn_right)); 294 return ic_mod(tn->tn_type, lc, rc); 295 case SHL: 296 lc = ic_expr(tn->tn_left); 297 rc = ic_expr(tn->tn_right); 298 return ic_shl(tn->tn_type, lc, rc); 299 case SHR: 300 lc = ic_expr(tn->tn_left); 301 rc = ic_expr(tn->tn_right); 302 return ic_shr(tn->tn_type, lc, rc); 303 case BITAND: 304 lc = ic_expr(tn->tn_left); 305 rc = ic_expr(tn->tn_right); 306 return ic_bitand(lc, rc); 307 case BITOR: 308 lc = ic_expr(tn->tn_left); 309 rc = ic_expr(tn->tn_right); 310 return ic_bitor(lc, rc); 311 case QUEST: 312 lc = ic_expr(tn->tn_right->tn_left); 313 rc = ic_expr(tn->tn_right->tn_right); 314 return ic_cond(lc, rc); 315 default: 316 return ic_any(tn->tn_type); 317 } 318 } 319 320 /* Build 'pointer to tp', 'array of tp' or 'function returning tp'. */ 321 type_t * 322 block_derive_type(type_t *tp, tspec_t t) 323 { 324 type_t *tp2; 325 326 tp2 = block_zero_alloc(sizeof(*tp2), "type"); 327 tp2->t_tspec = t; 328 tp2->t_subt = tp; 329 return tp2; 330 } 331 332 /* 333 * Derive 'pointer to tp' or 'function returning tp'. 334 * The memory is freed at the end of the current expression. 335 */ 336 type_t * 337 expr_derive_type(type_t *tp, tspec_t t) 338 { 339 type_t *tp2; 340 341 tp2 = expr_zero_alloc(sizeof(*tp2), "type"); 342 tp2->t_tspec = t; 343 tp2->t_subt = tp; 344 return tp2; 345 } 346 347 /* Create an expression from a unary or binary operator and its operands. */ 348 static tnode_t * 349 build_op(op_t op, bool sys, type_t *type, tnode_t *ln, tnode_t *rn) 350 { 351 352 tnode_t *ntn = expr_alloc_tnode(); 353 ntn->tn_op = op; 354 ntn->tn_type = type; 355 ntn->tn_sys = sys; 356 ntn->tn_left = ln; 357 ntn->tn_right = rn; 358 359 if (op == INDIR || op == FSEL) { 360 lint_assert(ln->tn_type->t_tspec == PTR); 361 tspec_t t = ln->tn_type->t_subt->t_tspec; 362 ntn->tn_lvalue = t != FUNC && t != VOID; 363 } 364 365 return ntn; 366 } 367 368 tnode_t * 369 build_constant(type_t *tp, val_t *v) 370 { 371 372 tnode_t *n = expr_alloc_tnode(); 373 n->tn_op = CON; 374 n->tn_type = tp; 375 n->tn_val = *v; 376 n->tn_val.v_tspec = tp->t_tspec; 377 free(v); 378 return n; 379 } 380 381 static tnode_t * 382 build_integer_constant(tspec_t t, int64_t si) 383 { 384 385 tnode_t *n = expr_alloc_tnode(); 386 n->tn_op = CON; 387 n->tn_type = gettyp(t); 388 n->tn_val.v_tspec = t; 389 n->tn_val.v_unsigned_since_c90 = false; 390 n->tn_val.v_char_constant = false; 391 n->tn_val.u.integer = si; 392 return n; 393 } 394 395 static void 396 fallback_symbol(sym_t *sym) 397 { 398 399 if (Tflag && fallback_symbol_strict_bool(sym)) 400 return; 401 402 if (block_level > 0 && (strcmp(sym->s_name, "__FUNCTION__") == 0 || 403 strcmp(sym->s_name, "__PRETTY_FUNCTION__") == 0)) { 404 /* __FUNCTION__/__PRETTY_FUNCTION__ is a GCC extension */ 405 gnuism(316); 406 // XXX: Should probably be ARRAY instead of PTR. 407 sym->s_type = block_derive_type(gettyp(CHAR), PTR); 408 sym->s_type->t_const = true; 409 return; 410 } 411 412 if (block_level > 0 && strcmp(sym->s_name, "__func__") == 0) { 413 if (!allow_c99) 414 /* __func__ is a C99 feature */ 415 warning(317); 416 /* C11 6.4.2.2 */ 417 sym->s_type = block_derive_type(gettyp(CHAR), ARRAY); 418 sym->s_type->t_const = true; 419 sym->s_type->t_dim = (int)strlen(funcsym->s_name) + 1; 420 return; 421 } 422 423 /* '%s' undefined */ 424 error(99, sym->s_name); 425 } 426 427 /* 428 * Functions that are predeclared by GCC or other compilers can be called 429 * with arbitrary arguments. Since lint usually runs after a successful 430 * compilation, it's the compiler's job to catch any errors. 431 */ 432 bool 433 is_compiler_builtin(const char *name) 434 { 435 /* https://gcc.gnu.org/onlinedocs/gcc/C-Extensions.html */ 436 if (allow_gcc) { 437 if (strncmp(name, "__atomic_", 9) == 0 || 438 strncmp(name, "__builtin_", 10) == 0 || 439 strcmp(name, "alloca") == 0 || 440 /* obsolete but still in use, as of 2021 */ 441 strncmp(name, "__sync_", 7) == 0) 442 return true; 443 } 444 445 /* https://software.intel.com/sites/landingpage/IntrinsicsGuide/ */ 446 if (strncmp(name, "_mm_", 4) == 0) 447 return true; 448 449 return false; 450 } 451 452 /* https://gcc.gnu.org/onlinedocs/gcc/Integer-Overflow-Builtins.html */ 453 static bool 454 is_gcc_bool_builtin(const char *name) 455 { 456 return strncmp(name, "__builtin_", 10) == 0 && 457 (str_ends_with(name, "_overflow") || 458 str_ends_with(name, "_overflow_p")); 459 } 460 461 static void 462 build_name_call(sym_t *sym) 463 { 464 465 if (is_compiler_builtin(sym->s_name)) { 466 /* 467 * Do not warn about these, just assume that they are regular 468 * functions compatible with non-prototype calling conventions. 469 */ 470 if (allow_gcc && is_gcc_bool_builtin(sym->s_name)) 471 sym->s_type = gettyp(BOOL); 472 } else if (allow_c99) { 473 /* function '%s' implicitly declared to return int */ 474 error(215, sym->s_name); 475 } else if (!allow_trad) { 476 /* function '%s' implicitly declared to return int */ 477 warning(215, sym->s_name); 478 } 479 480 /* XXX if !allow_c90, the symbol should be exported to level 0 */ 481 sym->s_type = block_derive_type(sym->s_type, FUNC); 482 } 483 484 /* Create a node for a name (symbol table entry). */ 485 tnode_t * 486 build_name(sym_t *sym, bool is_funcname) 487 { 488 489 if (sym->s_scl == NO_SCL && !in_gcc_attribute) { 490 sym->s_scl = EXTERN; 491 sym->s_def = DECL; 492 if (is_funcname) 493 build_name_call(sym); 494 else 495 fallback_symbol(sym); 496 } 497 498 lint_assert(sym->s_kind == FVFT || sym->s_kind == FMEMBER); 499 500 tnode_t *n = expr_alloc_tnode(); 501 n->tn_type = sym->s_type; 502 if (sym->s_scl == BOOL_CONST) { 503 n->tn_op = CON; 504 n->tn_val.v_tspec = BOOL; 505 n->tn_val.v_unsigned_since_c90 = false; 506 n->tn_val.v_char_constant = false; 507 n->tn_val.u.integer = sym->u.s_bool_constant ? 1 : 0; 508 } else if (sym->s_scl == ENUM_CONST) { 509 n->tn_op = CON; 510 n->tn_val.v_tspec = INT; /* ENUM is in n->tn_type */ 511 n->tn_val.v_unsigned_since_c90 = false; 512 n->tn_val.v_char_constant = false; 513 n->tn_val.u.integer = sym->u.s_enum_constant; 514 } else { 515 n->tn_op = NAME; 516 n->tn_sym = sym; 517 if (sym->s_kind == FVFT && sym->s_type->t_tspec != FUNC) 518 n->tn_lvalue = true; 519 } 520 521 return n; 522 } 523 524 tnode_t * 525 build_string(strg_t *strg) 526 { 527 size_t len = strg->st_len; 528 529 type_t *tp = expr_zero_alloc(sizeof(*tp), "type"); 530 tp->t_tspec = ARRAY; 531 tp->t_subt = gettyp(strg->st_char ? CHAR : WCHAR_TSPEC); 532 tp->t_dim = (int)(len + 1); 533 534 tnode_t *n = expr_alloc_tnode(); 535 n->tn_op = STRING; 536 n->tn_type = tp; 537 n->tn_lvalue = true; 538 539 n->tn_string = expr_zero_alloc(sizeof(*n->tn_string), "type.string"); 540 n->tn_string->st_char = strg->st_char; 541 n->tn_string->st_len = len; 542 543 size_t chsize = strg->st_char ? sizeof(char) : sizeof(wchar_t); 544 size_t size = (len + 1) * chsize; 545 n->tn_string->st_mem = expr_zero_alloc(size, "type.string.data"); 546 (void)memcpy(n->tn_string->st_mem, strg->st_mem, size); 547 free(strg->st_mem); 548 free(strg); 549 550 return n; 551 } 552 553 tnode_t * 554 build_generic_selection(const tnode_t *expr, 555 struct generic_association *sel) 556 { 557 tnode_t *default_result = NULL; 558 559 for (; sel != NULL; sel = sel->ga_prev) { 560 if (expr != NULL && 561 types_compatible(sel->ga_arg, expr->tn_type, 562 false, false, NULL)) 563 return sel->ga_result; 564 else if (sel->ga_arg == NULL) 565 default_result = sel->ga_result; 566 } 567 return default_result; 568 } 569 570 static bool 571 is_out_of_char_range(const tnode_t *tn) 572 { 573 return tn->tn_op == CON && 574 !tn->tn_val.v_char_constant && 575 !(0 <= tn->tn_val.u.integer && 576 tn->tn_val.u.integer < 1 << (CHAR_SIZE - 1)); 577 } 578 579 static bool 580 check_nonportable_char_comparison(op_t op, 581 const tnode_t *ln, tspec_t lt, 582 const tnode_t *rn, tspec_t rt) 583 { 584 if (!(hflag || pflag)) 585 return true; 586 587 if (lt == CHAR && is_out_of_char_range(rn)) { 588 char buf[128]; 589 (void)snprintf(buf, sizeof(buf), "%s %d", 590 op_name(op), (int)rn->tn_val.u.integer); 591 /* nonportable character comparison '%s' */ 592 warning(230, buf); 593 return false; 594 } 595 if (rt == CHAR && is_out_of_char_range(ln)) { 596 char buf[128]; 597 (void)snprintf(buf, sizeof(buf), "%d %s ?", 598 (int)ln->tn_val.u.integer, op_name(op)); 599 /* nonportable character comparison '%s' */ 600 warning(230, buf); 601 return false; 602 } 603 return true; 604 } 605 606 static void 607 check_integer_comparison(op_t op, tnode_t *ln, tnode_t *rn) 608 { 609 610 tspec_t lt = ln->tn_type->t_tspec; 611 tspec_t rt = rn->tn_type->t_tspec; 612 613 if (ln->tn_op != CON && rn->tn_op != CON) 614 return; 615 616 if (!is_integer(lt) || !is_integer(rt)) 617 return; 618 619 if (any_query_enabled && !in_system_header) { 620 if (lt == CHAR && rn->tn_op == CON && 621 !rn->tn_val.v_char_constant) { 622 /* comparison '%s' of 'char' with plain integer %d */ 623 query_message(14, 624 op_name(op), (int)rn->tn_val.u.integer); 625 } 626 if (rt == CHAR && ln->tn_op == CON && 627 !ln->tn_val.v_char_constant) { 628 /* comparison '%s' of 'char' with plain integer %d */ 629 query_message(14, 630 op_name(op), (int)ln->tn_val.u.integer); 631 } 632 } 633 634 if (!check_nonportable_char_comparison(op, ln, lt, rn, rt)) 635 return; 636 637 if (is_uinteger(lt) && !is_uinteger(rt) && 638 rn->tn_op == CON && rn->tn_val.u.integer <= 0) { 639 if (rn->tn_val.u.integer < 0) { 640 /* operator '%s' compares '%s' with '%s' */ 641 warning(162, op_name(op), 642 type_name(ln->tn_type), "negative constant"); 643 } else if (op == LT || op == GE) { 644 /* operator '%s' compares '%s' with '%s' */ 645 warning(162, op_name(op), type_name(ln->tn_type), "0"); 646 } 647 return; 648 } 649 if (is_uinteger(rt) && !is_uinteger(lt) && 650 ln->tn_op == CON && ln->tn_val.u.integer <= 0) { 651 if (ln->tn_val.u.integer < 0) { 652 /* operator '%s' compares '%s' with '%s' */ 653 warning(162, op_name(op), 654 "negative constant", type_name(rn->tn_type)); 655 } else if (op == GT || op == LE) { 656 /* operator '%s' compares '%s' with '%s' */ 657 warning(162, op_name(op), "0", type_name(rn->tn_type)); 658 } 659 return; 660 } 661 } 662 663 static const tspec_t arith_rank[] = { 664 LDOUBLE, DOUBLE, FLOAT, 665 #ifdef INT128_SIZE 666 UINT128, INT128, 667 #endif 668 ULLONG, LLONG, 669 ULONG, LONG, 670 UINT, INT, 671 }; 672 673 /* Keep unsigned in traditional C */ 674 static tspec_t 675 usual_arithmetic_conversion_trad(tspec_t lt, tspec_t rt) 676 { 677 678 size_t i; 679 for (i = 0; arith_rank[i] != INT; i++) 680 if (lt == arith_rank[i] || rt == arith_rank[i]) 681 break; 682 683 tspec_t t = arith_rank[i]; 684 if (is_uinteger(lt) || is_uinteger(rt)) 685 if (is_integer(t) && !is_uinteger(t)) 686 return unsigned_type(t); 687 return t; 688 } 689 690 static tspec_t 691 usual_arithmetic_conversion_c90(tspec_t lt, tspec_t rt) 692 { 693 694 if (lt == rt) 695 return lt; 696 697 if (lt == LCOMPLEX || rt == LCOMPLEX) 698 return LCOMPLEX; 699 if (lt == DCOMPLEX || rt == DCOMPLEX) 700 return DCOMPLEX; 701 if (lt == FCOMPLEX || rt == FCOMPLEX) 702 return FCOMPLEX; 703 if (lt == LDOUBLE || rt == LDOUBLE) 704 return LDOUBLE; 705 if (lt == DOUBLE || rt == DOUBLE) 706 return DOUBLE; 707 if (lt == FLOAT || rt == FLOAT) 708 return FLOAT; 709 710 /* 711 * If type A has more bits than type B, it should be able to hold all 712 * possible values of type B. 713 */ 714 if (size_in_bits(lt) > size_in_bits(rt)) 715 return lt; 716 if (size_in_bits(lt) < size_in_bits(rt)) 717 return rt; 718 719 size_t i; 720 for (i = 3; arith_rank[i] != INT; i++) 721 if (arith_rank[i] == lt || arith_rank[i] == rt) 722 break; 723 if ((is_uinteger(lt) || is_uinteger(rt)) && 724 !is_uinteger(arith_rank[i])) 725 i--; 726 return arith_rank[i]; 727 } 728 729 static tnode_t * 730 apply_usual_arithmetic_conversions(op_t op, tnode_t *tn, tspec_t t) 731 { 732 type_t *ntp = expr_dup_type(tn->tn_type); 733 ntp->t_tspec = t; 734 if (tn->tn_op != CON) { 735 /* usual arithmetic conversion for '%s' from '%s' to '%s' */ 736 query_message(4, op_name(op), 737 type_name(tn->tn_type), type_name(ntp)); 738 } 739 return convert(op, 0, ntp, tn); 740 } 741 742 /* 743 * Apply the "usual arithmetic conversions" (C99 6.3.1.8), which gives both 744 * operands the same type. 745 */ 746 static void 747 balance(op_t op, tnode_t **lnp, tnode_t **rnp) 748 { 749 750 tspec_t lt = (*lnp)->tn_type->t_tspec; 751 tspec_t rt = (*rnp)->tn_type->t_tspec; 752 if (!is_arithmetic(lt) || !is_arithmetic(rt)) 753 return; 754 755 tspec_t t = allow_c90 756 ? usual_arithmetic_conversion_c90(lt, rt) 757 : usual_arithmetic_conversion_trad(lt, rt); 758 759 if (t != lt) 760 *lnp = apply_usual_arithmetic_conversions(op, *lnp, t); 761 if (t != rt) 762 *rnp = apply_usual_arithmetic_conversions(op, *rnp, t); 763 } 764 765 /* 766 * Create a tree node for the unary & operator 767 */ 768 static tnode_t * 769 build_address(bool sys, tnode_t *tn, bool noign) 770 { 771 tspec_t t; 772 773 if (!noign && ((t = tn->tn_type->t_tspec) == ARRAY || t == FUNC)) { 774 if (!allow_c90) 775 /* '&' before array or function: ignored */ 776 warning(127); 777 return tn; 778 } 779 780 /* eliminate &* */ 781 if (tn->tn_op == INDIR && 782 tn->tn_left->tn_type->t_tspec == PTR && 783 tn->tn_left->tn_type->t_subt == tn->tn_type) { 784 return tn->tn_left; 785 } 786 787 return build_op(ADDR, sys, expr_derive_type(tn->tn_type, PTR), 788 tn, NULL); 789 } 790 791 /* 792 * XXX 793 * Note: There appear to be a number of bugs in detecting overflow in 794 * this function. An audit and a set of proper regression tests are needed. 795 * --Perry Metzger, Nov. 16, 2001 796 */ 797 /* 798 * Do only as much as necessary to compute constant expressions. 799 * Called only if the operator allows folding and all operands are constants. 800 */ 801 static tnode_t * 802 fold(tnode_t *tn) 803 { 804 805 val_t *v = xcalloc(1, sizeof(*v)); 806 v->v_tspec = tn->tn_type->t_tspec; 807 808 lint_assert(has_operands(tn)); 809 tspec_t t = tn->tn_left->tn_type->t_tspec; 810 bool utyp = !is_integer(t) || is_uinteger(t); 811 int64_t sl = tn->tn_left->tn_val.u.integer, sr = 0; 812 uint64_t ul = sl, ur = 0; 813 if (is_binary(tn)) 814 ur = sr = tn->tn_right->tn_val.u.integer; 815 816 int64_t mask = (int64_t)value_bits(size_in_bits(t)); 817 bool ovfl = false; 818 819 int64_t si; 820 switch (tn->tn_op) { 821 case UPLUS: 822 si = sl; 823 break; 824 case UMINUS: 825 si = sl == INT64_MIN ? sl : -sl; 826 if (sl != 0 && msb(si, t) == msb(sl, t)) 827 ovfl = true; 828 break; 829 case COMPL: 830 si = ~sl; 831 break; 832 case MULT: 833 if (utyp) { 834 si = (int64_t)(ul * ur); 835 if (si != (si & mask)) 836 ovfl = true; 837 else if ((ul != 0) && ((si / ul) != ur)) 838 ovfl = true; 839 } else { 840 si = sl * sr; 841 if (msb(si, t) != (msb(sl, t) ^ msb(sr, t))) 842 ovfl = true; 843 } 844 break; 845 case DIV: 846 if (sr == 0) { 847 /* division by 0 */ 848 error(139); 849 si = utyp ? -1 : INT64_MAX; 850 } else { 851 si = utyp ? (int64_t)(ul / ur) : sl / sr; 852 } 853 break; 854 case MOD: 855 if (sr == 0) { 856 /* modulus by 0 */ 857 error(140); 858 si = 0; 859 } else { 860 si = utyp ? (int64_t)(ul % ur) : sl % sr; 861 } 862 break; 863 case PLUS: 864 si = utyp ? (int64_t)(ul + ur) : sl + sr; 865 if (msb(sl, t) && msb(sr, t) && !msb(si, t)) 866 ovfl = true; 867 if (!utyp && !msb(sl, t) && !msb(sr, t) && msb(si, t)) 868 ovfl = true; 869 break; 870 case MINUS: 871 si = utyp ? (int64_t)(ul - ur) : sl - sr; 872 if (!utyp && msb(sl, t) && !msb(sr, t) && !msb(si, t)) 873 ovfl = true; 874 if (!msb(sl, t) && msb(sr, t) && msb(si, t)) 875 ovfl = true; 876 break; 877 case SHL: 878 /* TODO: warn about out-of-bounds 'sr'. */ 879 /* TODO: warn about overflow in signed '<<'. */ 880 si = utyp ? (int64_t)(ul << (sr & 63)) : sl << (sr & 63); 881 break; 882 case SHR: 883 /* 884 * The sign must be explicitly extended because shifts of 885 * signed values are implementation dependent. 886 */ 887 /* TODO: warn about out-of-bounds 'sr'. */ 888 si = (int64_t)(ul >> (sr & 63)); 889 si = convert_integer(si, t, size_in_bits(t) - (int)sr); 890 break; 891 case LT: 892 si = (utyp ? ul < ur : sl < sr) ? 1 : 0; 893 break; 894 case LE: 895 si = (utyp ? ul <= ur : sl <= sr) ? 1 : 0; 896 break; 897 case GE: 898 si = (utyp ? ul >= ur : sl >= sr) ? 1 : 0; 899 break; 900 case GT: 901 si = (utyp ? ul > ur : sl > sr) ? 1 : 0; 902 break; 903 case EQ: 904 si = (utyp ? ul == ur : sl == sr) ? 1 : 0; 905 break; 906 case NE: 907 si = (utyp ? ul != ur : sl != sr) ? 1 : 0; 908 break; 909 case BITAND: 910 si = utyp ? (int64_t)(ul & ur) : sl & sr; 911 break; 912 case BITXOR: 913 si = utyp ? (int64_t)(ul ^ ur) : sl ^ sr; 914 break; 915 case BITOR: 916 si = utyp ? (int64_t)(ul | ur) : sl | sr; 917 break; 918 default: 919 lint_assert(/*CONSTCOND*/false); 920 } 921 922 /* XXX: The overflow check does not work for 64-bit integers. */ 923 if (ovfl || 924 ((uint64_t)(si | mask) != ~(uint64_t)0 && (si & ~mask) != 0)) { 925 if (hflag) 926 /* operator '%s' produces integer overflow */ 927 warning(141, op_name(tn->tn_op)); 928 } 929 930 v->u.integer = convert_integer(si, t, 0); 931 932 tnode_t *cn = build_constant(tn->tn_type, v); 933 if (tn->tn_left->tn_system_dependent) 934 cn->tn_system_dependent = true; 935 if (is_binary(tn) && tn->tn_right->tn_system_dependent) 936 cn->tn_system_dependent = true; 937 938 return cn; 939 } 940 941 /* 942 * Create a new node for one of the operators POINT and ARROW. 943 */ 944 static tnode_t * 945 build_struct_access(op_t op, bool sys, tnode_t *ln, tnode_t *rn) 946 { 947 948 lint_assert(rn->tn_op == NAME); 949 lint_assert(is_member(rn->tn_sym)); 950 951 bool lvalue = op == ARROW || ln->tn_lvalue; 952 953 if (op == POINT) { 954 ln = build_address(sys, ln, true); 955 } else if (ln->tn_type->t_tspec != PTR) { 956 lint_assert(!allow_c90); 957 lint_assert(is_integer(ln->tn_type->t_tspec)); 958 ln = convert(NOOP, 0, expr_derive_type(gettyp(VOID), PTR), ln); 959 } 960 961 tnode_t *ctn = build_integer_constant(PTRDIFF_TSPEC, 962 rn->tn_sym->u.s_member.sm_offset_in_bits / CHAR_SIZE); 963 964 type_t *ptr_tp = expr_derive_type(rn->tn_type, PTR); 965 tnode_t *ntn = build_op(PLUS, sys, ptr_tp, ln, ctn); 966 if (ln->tn_op == CON) 967 ntn = fold(ntn); 968 969 op_t nop = rn->tn_type->t_bitfield ? FSEL : INDIR; 970 ntn = build_op(nop, sys, ntn->tn_type->t_subt, ntn, NULL); 971 if (!lvalue) 972 ntn->tn_lvalue = false; 973 974 return ntn; 975 } 976 977 /* 978 * Get the size in bytes of type tp->t_subt, as a constant expression of type 979 * ptrdiff_t as seen from the target platform. 980 */ 981 static tnode_t * 982 subt_size_in_bytes(type_t *tp) 983 { 984 985 lint_assert(tp->t_tspec == PTR); 986 tp = tp->t_subt; 987 988 int elem = 1; 989 while (tp->t_tspec == ARRAY) { 990 elem *= tp->t_dim; 991 tp = tp->t_subt; 992 } 993 994 int elsz_in_bits = 0; 995 switch (tp->t_tspec) { 996 case FUNC: 997 /* pointer to function is not allowed here */ 998 error(110); 999 break; 1000 case VOID: 1001 /* cannot do pointer arithmetic on operand of unknown size */ 1002 gnuism(136); 1003 break; 1004 case STRUCT: 1005 case UNION: 1006 if ((elsz_in_bits = (int)tp->t_sou->sou_size_in_bits) == 0) 1007 /* cannot do pointer arithmetic on operand of ... */ 1008 error(136); 1009 break; 1010 case ENUM: 1011 if (is_incomplete(tp)) { 1012 /* cannot do pointer arithmetic on operand of ... */ 1013 warning(136); 1014 } 1015 /* FALLTHROUGH */ 1016 default: 1017 if ((elsz_in_bits = size_in_bits(tp->t_tspec)) == 0) { 1018 /* cannot do pointer arithmetic on operand of ... */ 1019 error(136); 1020 } else { 1021 lint_assert(elsz_in_bits != -1); 1022 } 1023 break; 1024 } 1025 1026 if (elem == 0 && elsz_in_bits != 0) { 1027 /* cannot do pointer arithmetic on operand of unknown size */ 1028 error(136); 1029 } 1030 1031 if (elsz_in_bits == 0) 1032 elsz_in_bits = CHAR_SIZE; 1033 1034 return build_integer_constant(PTRDIFF_TSPEC, 1035 (int64_t)(elem * elsz_in_bits / CHAR_SIZE)); 1036 } 1037 1038 /* 1039 * Create a node for INCAFT, INCBEF, DECAFT and DECBEF. 1040 */ 1041 static tnode_t * 1042 build_prepost_incdec(op_t op, bool sys, tnode_t *ln) 1043 { 1044 1045 lint_assert(ln != NULL); 1046 tnode_t *cn = ln->tn_type->t_tspec == PTR 1047 ? subt_size_in_bytes(ln->tn_type) 1048 : build_integer_constant(INT, 1); 1049 return build_op(op, sys, ln->tn_type, ln, cn); 1050 } 1051 1052 static void 1053 check_enum_array_index(const tnode_t *ln, const tnode_t *rn) 1054 { 1055 1056 if (ln->tn_op != ADDR || ln->tn_left->tn_op != NAME) 1057 return; 1058 1059 const type_t *ltp = ln->tn_left->tn_type; 1060 if (ltp->t_tspec != ARRAY || ltp->t_incomplete_array) 1061 return; 1062 1063 if (rn->tn_op != CVT || !rn->tn_type->t_is_enum) 1064 return; 1065 if (rn->tn_left->tn_op != LOAD) 1066 return; 1067 1068 const type_t *rtp = rn->tn_left->tn_type; 1069 const sym_t *ec = rtp->t_enum->en_first_enumerator; 1070 const sym_t *max_ec = ec; 1071 lint_assert(ec != NULL); 1072 for (ec = ec->s_next; ec != NULL; ec = ec->s_next) 1073 if (ec->u.s_enum_constant > max_ec->u.s_enum_constant) 1074 max_ec = ec; 1075 1076 int64_t max_enum_value = max_ec->u.s_enum_constant; 1077 lint_assert(INT_MIN <= max_enum_value && max_enum_value <= INT_MAX); 1078 1079 int max_array_index = ltp->t_dim - 1; 1080 if (max_enum_value == max_array_index) 1081 return; 1082 1083 /* 1084 * If the name of the largest enum constant contains 'MAX' or 'NUM', 1085 * that constant is typically not part of the allowed enum values but a 1086 * marker for the number of actual enum values. 1087 */ 1088 if (max_enum_value == max_array_index + 1 && 1089 (strstr(max_ec->s_name, "MAX") != NULL || 1090 strstr(max_ec->s_name, "max") != NULL || 1091 strstr(max_ec->s_name, "NUM") != NULL || 1092 strstr(max_ec->s_name, "num") != NULL)) 1093 return; 1094 1095 /* maximum value %d of '%s' does not match maximum array index %d */ 1096 warning(348, (int)max_enum_value, type_name(rtp), max_array_index); 1097 print_previous_declaration(max_ec); 1098 } 1099 1100 /* 1101 * Create a node for operators PLUS and MINUS. 1102 */ 1103 static tnode_t * 1104 build_plus_minus(op_t op, bool sys, tnode_t *ln, tnode_t *rn) 1105 { 1106 1107 /* If pointer and integer, move the pointer to the left. */ 1108 if (rn->tn_type->t_tspec == PTR && is_integer(ln->tn_type->t_tspec)) { 1109 tnode_t *tmp = ln; 1110 ln = rn; 1111 rn = tmp; 1112 /* pointer addition has integer on the left-hand side */ 1113 query_message(5); 1114 } 1115 1116 /* pointer +- integer */ 1117 if (ln->tn_type->t_tspec == PTR && rn->tn_type->t_tspec != PTR) { 1118 lint_assert(is_integer(rn->tn_type->t_tspec)); 1119 1120 check_ctype_macro_invocation(ln, rn); 1121 check_enum_array_index(ln, rn); 1122 1123 tnode_t *elsz = subt_size_in_bytes(ln->tn_type); 1124 if (rn->tn_type->t_tspec != elsz->tn_type->t_tspec) 1125 rn = convert(NOOP, 0, elsz->tn_type, rn); 1126 1127 tnode_t *prod = build_op(MULT, sys, rn->tn_type, rn, elsz); 1128 if (rn->tn_op == CON) 1129 prod = fold(prod); 1130 1131 return build_op(op, sys, ln->tn_type, ln, prod); 1132 } 1133 1134 /* pointer - pointer */ 1135 if (rn->tn_type->t_tspec == PTR) { 1136 lint_assert(ln->tn_type->t_tspec == PTR); 1137 lint_assert(op == MINUS); 1138 1139 type_t *ptrdiff = gettyp(PTRDIFF_TSPEC); 1140 tnode_t *raw_diff = build_op(op, sys, ptrdiff, ln, rn); 1141 if (ln->tn_op == CON && rn->tn_op == CON) 1142 raw_diff = fold(raw_diff); 1143 1144 tnode_t *elsz = subt_size_in_bytes(ln->tn_type); 1145 balance(NOOP, &raw_diff, &elsz); 1146 1147 return build_op(DIV, sys, ptrdiff, raw_diff, elsz); 1148 } 1149 1150 return build_op(op, sys, ln->tn_type, ln, rn); 1151 } 1152 1153 /* 1154 * Create a node for operators SHL and SHR. 1155 */ 1156 static tnode_t * 1157 build_bit_shift(op_t op, bool sys, tnode_t *ln, tnode_t *rn) 1158 { 1159 1160 if (!allow_c90 && rn->tn_type->t_tspec != INT) 1161 // XXX: C1978 7.5 says: "Both [operators] perform the usual 1162 // arithmetic conversions on their operands." 1163 // TODO: Add a test to exercise this part of the code. 1164 rn = convert(NOOP, 0, gettyp(INT), rn); 1165 return build_op(op, sys, ln->tn_type, ln, rn); 1166 } 1167 1168 static bool 1169 is_null_pointer(const tnode_t *tn) 1170 { 1171 tspec_t t = tn->tn_type->t_tspec; 1172 1173 // TODO: Investigate how other pointers are stored, in particular, 1174 // whether a pointer constant can have a non-zero value. 1175 // If not, simplify the code below. 1176 return ((t == PTR && tn->tn_type->t_subt->t_tspec == VOID) 1177 || is_integer(t)) 1178 && (tn->tn_op == CON && tn->tn_val.u.integer == 0); 1179 } 1180 1181 /* Return a type based on tp1, with added qualifiers from tp2. */ 1182 static type_t * 1183 merge_qualifiers(type_t *tp1, const type_t *tp2) 1184 { 1185 1186 lint_assert(tp1->t_tspec == PTR); 1187 lint_assert(tp2->t_tspec == PTR); 1188 1189 bool c1 = tp1->t_subt->t_const; 1190 bool c2 = tp2->t_subt->t_const; 1191 bool v1 = tp1->t_subt->t_volatile; 1192 bool v2 = tp2->t_subt->t_volatile; 1193 1194 if (c1 == (c1 | c2) && v1 == (v1 | v2)) 1195 return tp1; 1196 1197 type_t *nstp = expr_dup_type(tp1->t_subt); 1198 nstp->t_const |= c2; 1199 nstp->t_volatile |= v2; 1200 1201 type_t *ntp = expr_dup_type(tp1); 1202 ntp->t_subt = nstp; 1203 return ntp; 1204 } 1205 1206 /* See C99 6.5.15 "Conditional operator". */ 1207 static tnode_t * 1208 build_colon(bool sys, tnode_t *ln, tnode_t *rn) 1209 { 1210 1211 tspec_t lt = ln->tn_type->t_tspec; 1212 tspec_t rt = rn->tn_type->t_tspec; 1213 1214 type_t *tp; 1215 if (is_arithmetic(lt) && is_arithmetic(rt)) { 1216 /* The operands were already balanced in build_binary. */ 1217 tp = ln->tn_type; 1218 } else if (lt == BOOL && rt == BOOL) { 1219 tp = ln->tn_type; 1220 } else if (lt == VOID || rt == VOID) { 1221 tp = gettyp(VOID); 1222 } else if (is_struct_or_union(lt)) { 1223 /* Both types must be identical. */ 1224 lint_assert(is_struct_or_union(rt)); 1225 lint_assert(ln->tn_type->t_sou == rn->tn_type->t_sou); 1226 if (is_incomplete(ln->tn_type)) { 1227 /* unknown operand size, op '%s' */ 1228 error(138, op_name(COLON)); 1229 return NULL; 1230 } 1231 tp = ln->tn_type; 1232 } else if (lt == PTR && is_integer(rt)) { 1233 if (rt != PTRDIFF_TSPEC) 1234 rn = convert(NOOP, 0, gettyp(PTRDIFF_TSPEC), rn); 1235 tp = ln->tn_type; 1236 } else if (rt == PTR && is_integer(lt)) { 1237 if (lt != PTRDIFF_TSPEC) 1238 ln = convert(NOOP, 0, gettyp(PTRDIFF_TSPEC), ln); 1239 tp = rn->tn_type; 1240 } else if (lt == PTR && is_null_pointer(rn)) { 1241 tp = merge_qualifiers(ln->tn_type, rn->tn_type); 1242 } else if (rt == PTR && is_null_pointer(ln)) { 1243 tp = merge_qualifiers(rn->tn_type, ln->tn_type); 1244 } else if (lt == PTR && ln->tn_type->t_subt->t_tspec == VOID) { 1245 tp = merge_qualifiers(ln->tn_type, rn->tn_type); 1246 } else if (rt == PTR && rn->tn_type->t_subt->t_tspec == VOID) { 1247 tp = merge_qualifiers(rn->tn_type, ln->tn_type); 1248 } else { 1249 /* 1250 * XXX For now we simply take the left type. This is probably 1251 * wrong, if one type contains a function prototype and the 1252 * other one, at the same place, only an old-style declaration. 1253 */ 1254 tp = merge_qualifiers(ln->tn_type, rn->tn_type); 1255 } 1256 1257 return build_op(COLON, sys, tp, ln, rn); 1258 } 1259 1260 /* TODO: check for varargs */ 1261 static bool 1262 is_cast_redundant(const tnode_t *tn) 1263 { 1264 const type_t *ntp = tn->tn_type, *otp = tn_ck_left(tn)->tn_type; 1265 tspec_t nt = ntp->t_tspec, ot = otp->t_tspec; 1266 1267 if (nt == BOOL || ot == BOOL) 1268 return nt == BOOL && ot == BOOL; 1269 1270 if (is_integer(nt) && is_integer(ot)) { 1271 unsigned int nw = width_in_bits(ntp), ow = width_in_bits(otp); 1272 if (is_uinteger(nt) == is_uinteger(ot)) 1273 return nw >= ow; 1274 return is_uinteger(ot) && nw > ow; 1275 } 1276 1277 if (is_complex(nt) || is_complex(ot)) 1278 return is_complex(nt) && is_complex(ot) && 1279 size_in_bits(nt) >= size_in_bits(ot); 1280 1281 if (is_floating(nt) && is_floating(ot)) 1282 return size_in_bits(nt) >= size_in_bits(ot); 1283 1284 if (nt == PTR && ot == PTR) { 1285 if (!ntp->t_subt->t_const && otp->t_subt->t_const) 1286 return false; 1287 if (!ntp->t_subt->t_volatile && otp->t_subt->t_volatile) 1288 return false; 1289 1290 if (ntp->t_subt->t_tspec == VOID || 1291 otp->t_subt->t_tspec == VOID || 1292 types_compatible(ntp->t_subt, otp->t_subt, 1293 false, false, NULL)) 1294 return true; 1295 } 1296 1297 return false; 1298 } 1299 1300 static bool 1301 is_assignment(op_t op) 1302 { 1303 1304 return op == ASSIGN || 1305 op == MULASS || 1306 op == DIVASS || 1307 op == MODASS || 1308 op == ADDASS || 1309 op == SUBASS || 1310 op == SHLASS || 1311 op == SHRASS || 1312 op == ANDASS || 1313 op == XORASS || 1314 op == ORASS || 1315 op == RETURN || 1316 op == INIT; 1317 } 1318 1319 /* Create a node for an assignment operator (both '=' and 'op='). */ 1320 static tnode_t * 1321 build_assignment(op_t op, bool sys, tnode_t *ln, tnode_t *rn) 1322 { 1323 1324 tspec_t lt = ln->tn_type->t_tspec; 1325 tspec_t rt = rn->tn_type->t_tspec; 1326 1327 if (any_query_enabled && is_assignment(rn->tn_op)) { 1328 /* chained assignment with '%s' and '%s' */ 1329 query_message(10, op_name(op), op_name(rn->tn_op)); 1330 } 1331 1332 if ((op == ADDASS || op == SUBASS) && lt == PTR) { 1333 lint_assert(is_integer(rt)); 1334 tnode_t *ctn = subt_size_in_bytes(ln->tn_type); 1335 if (rn->tn_type->t_tspec != ctn->tn_type->t_tspec) 1336 rn = convert(NOOP, 0, ctn->tn_type, rn); 1337 rn = build_op(MULT, sys, rn->tn_type, rn, ctn); 1338 if (rn->tn_left->tn_op == CON) 1339 rn = fold(rn); 1340 } 1341 1342 if ((op == ASSIGN || op == RETURN || op == INIT) && 1343 (lt == STRUCT || rt == STRUCT)) { 1344 lint_assert(lt == rt); 1345 lint_assert(ln->tn_type->t_sou == rn->tn_type->t_sou); 1346 if (is_incomplete(ln->tn_type)) { 1347 if (op == RETURN) { 1348 /* cannot return incomplete type */ 1349 error(212); 1350 } else { 1351 /* unknown operand size, op '%s' */ 1352 error(138, op_name(op)); 1353 } 1354 return NULL; 1355 } 1356 } 1357 1358 if (op == SHLASS && hflag && allow_trad && allow_c90 1359 && portable_rank_cmp(lt, rt) < 0) 1360 /* semantics of '%s' change in C90; ... */ 1361 warning(118, "<<="); 1362 1363 if (op != SHLASS && op != SHRASS 1364 && (op == ASSIGN || lt != PTR) 1365 && (lt != rt || (ln->tn_type->t_bitfield && rn->tn_op == CON))) { 1366 rn = convert(op, 0, ln->tn_type, rn); 1367 rt = lt; 1368 } 1369 1370 if (any_query_enabled && rn->tn_op == CVT && rn->tn_cast && 1371 types_compatible(ln->tn_type, rn->tn_type, false, false, NULL) && 1372 is_cast_redundant(rn)) { 1373 /* redundant cast from '%s' to '%s' before assignment */ 1374 query_message(7, 1375 type_name(rn->tn_left->tn_type), type_name(rn->tn_type)); 1376 } 1377 1378 return build_op(op, sys, ln->tn_type, ln, rn); 1379 } 1380 1381 /* 1382 * Create a node for REAL, IMAG 1383 */ 1384 static tnode_t * 1385 build_real_imag(op_t op, bool sys, tnode_t *ln) 1386 { 1387 1388 lint_assert(ln != NULL); 1389 if (ln->tn_op == NAME) { 1390 /* 1391 * This may be too much, but it avoids wrong warnings. See 1392 * d_c99_complex_split.c. 1393 */ 1394 mark_as_used(ln->tn_sym, false, false); 1395 mark_as_set(ln->tn_sym); 1396 } 1397 1398 tspec_t t; 1399 switch (ln->tn_type->t_tspec) { 1400 case LCOMPLEX: 1401 t = LDOUBLE; 1402 break; 1403 case DCOMPLEX: 1404 t = DOUBLE; 1405 break; 1406 case FCOMPLEX: 1407 t = FLOAT; 1408 break; 1409 default: 1410 /* '__%s__' is illegal for type '%s' */ 1411 error(276, op == REAL ? "real" : "imag", 1412 type_name(ln->tn_type)); 1413 return NULL; 1414 } 1415 1416 tnode_t *ntn = build_op(op, sys, gettyp(t), ln, NULL); 1417 ntn->tn_lvalue = true; 1418 return ntn; 1419 } 1420 1421 static bool 1422 is_confusing_precedence(op_t op, op_t lop, bool lparen, op_t rop, bool rparen) 1423 { 1424 1425 if (op == SHL || op == SHR) { 1426 if (!lparen && (lop == PLUS || lop == MINUS)) 1427 return true; 1428 if (!rparen && (rop == PLUS || rop == MINUS)) 1429 return true; 1430 return false; 1431 } 1432 1433 if (op == LOGOR) { 1434 if (!lparen && lop == LOGAND) 1435 return true; 1436 if (!rparen && rop == LOGAND) 1437 return true; 1438 return false; 1439 } 1440 1441 lint_assert(op == BITAND || op == BITXOR || op == BITOR); 1442 if (!lparen && lop != op) { 1443 if (lop == PLUS || lop == MINUS) 1444 return true; 1445 if (lop == BITAND || lop == BITXOR) 1446 return true; 1447 } 1448 if (!rparen && rop != op) { 1449 if (rop == PLUS || rop == MINUS) 1450 return true; 1451 if (rop == BITAND || rop == BITXOR) 1452 return true; 1453 } 1454 return false; 1455 } 1456 1457 /* 1458 * Print a warning if the given node has operands which should be 1459 * parenthesized. 1460 * 1461 * XXX Does not work if an operand is a constant expression. Constant 1462 * expressions are already folded. 1463 */ 1464 static void 1465 check_precedence_confusion(tnode_t *tn) 1466 { 1467 tnode_t *ln, *rn; 1468 1469 if (!hflag) 1470 return; 1471 1472 debug_node(tn); 1473 1474 lint_assert(is_binary(tn)); 1475 for (ln = tn->tn_left; ln->tn_op == CVT; ln = ln->tn_left) 1476 continue; 1477 for (rn = tn->tn_right; rn->tn_op == CVT; rn = rn->tn_left) 1478 continue; 1479 1480 if (is_confusing_precedence(tn->tn_op, 1481 ln->tn_op, ln->tn_parenthesized, 1482 rn->tn_op, rn->tn_parenthesized)) { 1483 /* precedence confusion possible: parenthesize! */ 1484 warning(169); 1485 } 1486 } 1487 1488 /* 1489 * Fold constant nodes, as much as is needed for comparing the value with 0. 1490 */ 1491 static tnode_t * 1492 fold_bool(tnode_t *tn) 1493 { 1494 1495 val_t *v = xcalloc(1, sizeof(*v)); 1496 v->v_tspec = tn->tn_type->t_tspec; 1497 lint_assert(v->v_tspec == INT || (Tflag && v->v_tspec == BOOL)); 1498 1499 lint_assert(has_operands(tn)); 1500 bool l = constant_is_nonzero(tn->tn_left); 1501 bool r = is_binary(tn) && constant_is_nonzero(tn->tn_right); 1502 1503 switch (tn->tn_op) { 1504 case NOT: 1505 if (hflag && !suppress_constcond) 1506 /* constant operand to '!' */ 1507 warning(239); 1508 v->u.integer = !l ? 1 : 0; 1509 break; 1510 case LOGAND: 1511 v->u.integer = l && r ? 1 : 0; 1512 break; 1513 case LOGOR: 1514 v->u.integer = l || r ? 1 : 0; 1515 break; 1516 default: 1517 lint_assert(/*CONSTCOND*/false); 1518 } 1519 1520 return build_constant(tn->tn_type, v); 1521 } 1522 1523 static long double 1524 floating_error_value(tspec_t t, long double lv) 1525 { 1526 if (t == FLOAT) 1527 return lv < 0 ? -FLT_MAX : FLT_MAX; 1528 if (t == DOUBLE) 1529 return lv < 0 ? -DBL_MAX : DBL_MAX; 1530 /* 1531 * When NetBSD is cross-built in MKLINT=yes mode on x86_64 for sparc64, 1532 * tools/lint checks this code while building usr.bin/xlint. In that 1533 * situation, lint uses the preprocessor for sparc64, in which the type 1534 * 'long double' is IEEE-754-binary128, affecting the macro LDBL_MAX 1535 * below. The type 'long double', as well as the strtold 1536 * implementation, comes from the host platform x86_64 though, where 1537 * 'long double' consumes 128 bits as well but only uses 80 of them. 1538 * The exponent range of the two 'long double' types is the same, but 1539 * the maximum finite value differs due to the extended precision on 1540 * sparc64. 1541 * 1542 * To properly handle the data types of the target platform, lint would 1543 * have to implement the floating-point types in a platform-independent 1544 * way, which is not worth the effort, given how few programs 1545 * practically use 'long double'. 1546 */ 1547 /* LINTED 248: floating-point constant out of range */ 1548 long double max = LDBL_MAX; 1549 return lv < 0 ? -max : max; 1550 } 1551 1552 static bool 1553 is_floating_overflow(tspec_t t, long double val) 1554 { 1555 if (fpe != 0 || isfinite(val) == 0) 1556 return true; 1557 if (t == FLOAT && (val > FLT_MAX || val < -FLT_MAX)) 1558 return true; 1559 if (t == DOUBLE && (val > DBL_MAX || val < -DBL_MAX)) 1560 return true; 1561 return false; 1562 } 1563 1564 /* 1565 * Fold constant nodes having operands with floating point type. 1566 */ 1567 static tnode_t * 1568 fold_float(tnode_t *tn) 1569 { 1570 1571 fpe = 0; 1572 1573 tspec_t t = tn->tn_type->t_tspec; 1574 1575 val_t *v = xcalloc(1, sizeof(*v)); 1576 v->v_tspec = t; 1577 1578 lint_assert(is_floating(t)); 1579 lint_assert(has_operands(tn)); 1580 lint_assert(t == tn->tn_left->tn_type->t_tspec); 1581 lint_assert(!is_binary(tn) || t == tn->tn_right->tn_type->t_tspec); 1582 1583 long double lv = tn->tn_left->tn_val.u.floating; 1584 long double rv = is_binary(tn) ? tn->tn_right->tn_val.u.floating : 0.0; 1585 1586 switch (tn->tn_op) { 1587 case UPLUS: 1588 v->u.floating = lv; 1589 break; 1590 case UMINUS: 1591 v->u.floating = -lv; 1592 break; 1593 case MULT: 1594 v->u.floating = lv * rv; 1595 break; 1596 case DIV: 1597 if (rv == 0.0) { 1598 /* division by 0 */ 1599 error(139); 1600 v->u.floating = floating_error_value(t, lv); 1601 } else { 1602 v->u.floating = lv / rv; 1603 } 1604 break; 1605 case PLUS: 1606 v->u.floating = lv + rv; 1607 break; 1608 case MINUS: 1609 v->u.floating = lv - rv; 1610 break; 1611 case LT: 1612 v->u.integer = lv < rv ? 1 : 0; 1613 break; 1614 case LE: 1615 v->u.integer = lv <= rv ? 1 : 0; 1616 break; 1617 case GE: 1618 v->u.integer = lv >= rv ? 1 : 0; 1619 break; 1620 case GT: 1621 v->u.integer = lv > rv ? 1 : 0; 1622 break; 1623 case EQ: 1624 v->u.integer = lv == rv ? 1 : 0; 1625 break; 1626 case NE: 1627 v->u.integer = lv != rv ? 1 : 0; 1628 break; 1629 default: 1630 lint_assert(/*CONSTCOND*/false); 1631 } 1632 1633 // XXX: Must not access u.floating after setting u.integer. 1634 lint_assert(fpe != 0 || isnan(v->u.floating) == 0); 1635 if (is_complex(v->v_tspec)) { 1636 /* 1637 * Don't warn, as lint doesn't model the imaginary part of 1638 * complex numbers. 1639 */ 1640 fpe = 0; 1641 } else if (is_floating_overflow(t, v->u.floating)) { 1642 /* operator '%s' produces floating point overflow */ 1643 warning(142, op_name(tn->tn_op)); 1644 v->u.floating = floating_error_value(t, v->u.floating); 1645 fpe = 0; 1646 } 1647 1648 return build_constant(tn->tn_type, v); 1649 } 1650 1651 static void 1652 use(const tnode_t *tn) 1653 { 1654 if (tn == NULL) 1655 return; 1656 switch (tn->tn_op) { 1657 case NAME: 1658 mark_as_used(tn->tn_sym, false /* XXX */, false /* XXX */); 1659 break; 1660 case CON: 1661 case STRING: 1662 break; 1663 default: 1664 lint_assert(has_operands(tn)); 1665 use(tn->tn_left); 1666 if (is_binary(tn) || tn->tn_op == PUSH) 1667 use(tn->tn_right); 1668 } 1669 } 1670 1671 /* 1672 * Create a tree node for a binary operator and its two operands. Also called 1673 * for unary operators; in that case rn is NULL. 1674 * 1675 * Function calls, sizeof and casts are handled elsewhere. 1676 */ 1677 tnode_t * 1678 build_binary(tnode_t *ln, op_t op, bool sys, tnode_t *rn) 1679 { 1680 const mod_t *mp = &modtab[op]; 1681 1682 /* If there was an error in one of the operands, return. */ 1683 if (ln == NULL || (mp->m_binary && rn == NULL)) 1684 return NULL; 1685 1686 /* 1687 * Apply class conversions to the left operand, but only if its value 1688 * is needed or compared with zero. 1689 */ 1690 if (mp->m_value_context || mp->m_compares_with_zero) 1691 ln = cconv(ln); 1692 /* 1693 * The right operand is almost always in a test or value context, 1694 * except if it is a struct or union member. 1695 */ 1696 if (mp->m_binary && op != ARROW && op != POINT) 1697 rn = cconv(rn); 1698 1699 /* 1700 * Print some warnings for comparisons of unsigned values with 1701 * constants lower than or equal to null. This must be done before 1702 * promote() because otherwise unsigned char and unsigned short would 1703 * be promoted to int. Types are also tested to be CHAR, which would 1704 * also become int. 1705 */ 1706 if (mp->m_comparison) 1707 check_integer_comparison(op, ln, rn); 1708 1709 if (mp->m_value_context || mp->m_compares_with_zero) 1710 ln = promote(op, false, ln); 1711 if (mp->m_binary && op != ARROW && op != POINT && 1712 op != ASSIGN && op != RETURN && op != INIT) { 1713 rn = promote(op, false, rn); 1714 } 1715 1716 /* 1717 * If the result of the operation is different for signed or unsigned 1718 * operands and one of the operands is signed only in C90, print a 1719 * warning. 1720 */ 1721 if (mp->m_warn_if_left_unsigned_in_c90 && 1722 ln->tn_op == CON && ln->tn_val.v_unsigned_since_c90) { 1723 /* C90 treats constant as unsigned, op '%s' */ 1724 warning(218, op_name(op)); 1725 ln->tn_val.v_unsigned_since_c90 = false; 1726 } 1727 if (mp->m_warn_if_right_unsigned_in_c90 && 1728 rn->tn_op == CON && rn->tn_val.v_unsigned_since_c90) { 1729 /* C90 treats constant as unsigned, op '%s' */ 1730 warning(218, op_name(op)); 1731 rn->tn_val.v_unsigned_since_c90 = false; 1732 } 1733 1734 /* Make sure both operands are of the same type */ 1735 if (mp->m_balance_operands || (!allow_c90 && (op == SHL || op == SHR))) 1736 balance(op, &ln, &rn); 1737 1738 /* 1739 * Check types for compatibility with the operation and mutual 1740 * compatibility. Return if there are serious problems. 1741 */ 1742 if (!typeok(op, 0, ln, rn)) 1743 return NULL; 1744 1745 /* And now create the node. */ 1746 tnode_t *ntn; 1747 switch (op) { 1748 case POINT: 1749 case ARROW: 1750 ntn = build_struct_access(op, sys, ln, rn); 1751 break; 1752 case INCAFT: 1753 case DECAFT: 1754 case INCBEF: 1755 case DECBEF: 1756 ntn = build_prepost_incdec(op, sys, ln); 1757 break; 1758 case ADDR: 1759 ntn = build_address(sys, ln, false); 1760 break; 1761 case INDIR: 1762 ntn = build_op(INDIR, sys, ln->tn_type->t_subt, ln, NULL); 1763 break; 1764 case PLUS: 1765 case MINUS: 1766 ntn = build_plus_minus(op, sys, ln, rn); 1767 break; 1768 case SHL: 1769 case SHR: 1770 ntn = build_bit_shift(op, sys, ln, rn); 1771 break; 1772 case COLON: 1773 ntn = build_colon(sys, ln, rn); 1774 break; 1775 case ASSIGN: 1776 case MULASS: 1777 case DIVASS: 1778 case MODASS: 1779 case ADDASS: 1780 case SUBASS: 1781 case SHLASS: 1782 case SHRASS: 1783 case ANDASS: 1784 case XORASS: 1785 case ORASS: 1786 case RETURN: 1787 case INIT: 1788 ntn = build_assignment(op, sys, ln, rn); 1789 break; 1790 case COMMA: 1791 if (any_query_enabled) { 1792 /* comma operator with types '%s' and '%s' */ 1793 query_message(12, 1794 type_name(ln->tn_type), type_name(rn->tn_type)); 1795 } 1796 /* FALLTHROUGH */ 1797 case QUEST: 1798 ntn = build_op(op, sys, rn->tn_type, ln, rn); 1799 break; 1800 case REAL: 1801 case IMAG: 1802 ntn = build_real_imag(op, sys, ln); 1803 break; 1804 default: 1805 lint_assert(mp->m_binary == (rn != NULL)); 1806 type_t *rettp = mp->m_returns_bool 1807 ? gettyp(Tflag ? BOOL : INT) : ln->tn_type; 1808 ntn = build_op(op, sys, rettp, ln, rn); 1809 break; 1810 } 1811 1812 /* Return if an error occurred. */ 1813 if (ntn == NULL) 1814 return NULL; 1815 1816 /* Print a warning if precedence confusion is possible */ 1817 if (mp->m_possible_precedence_confusion) 1818 check_precedence_confusion(ntn); 1819 1820 /* 1821 * Print a warning if one of the operands is in a context where it is 1822 * compared with zero and if this operand is a constant. 1823 */ 1824 if (hflag && !suppress_constcond && 1825 mp->m_compares_with_zero && 1826 (ln->tn_op == CON || 1827 ((mp->m_binary && op != QUEST) && rn->tn_op == CON)) && 1828 /* XXX: rn->tn_system_dependent should be checked as well */ 1829 !ln->tn_system_dependent) { 1830 /* constant in conditional context */ 1831 warning(161); 1832 } 1833 1834 /* Fold if the operator requires it */ 1835 if (mp->m_fold_constant_operands) { 1836 if (ln->tn_op == CON && (!mp->m_binary || rn->tn_op == CON)) { 1837 if (mp->m_compares_with_zero) { 1838 ntn = fold_bool(ntn); 1839 } else if (is_floating(ntn->tn_type->t_tspec)) { 1840 ntn = fold_float(ntn); 1841 } else { 1842 ntn = fold(ntn); 1843 } 1844 } else if (op == QUEST && ln->tn_op == CON) { 1845 lint_assert(has_operands(rn)); 1846 use(ln->tn_val.u.integer != 0 1847 ? rn->tn_right : rn->tn_left); 1848 ntn = ln->tn_val.u.integer != 0 1849 ? rn->tn_left : rn->tn_right; 1850 } 1851 } 1852 1853 return ntn; 1854 } 1855 1856 tnode_t * 1857 build_unary(op_t op, bool sys, tnode_t *tn) 1858 { 1859 return build_binary(tn, op, sys, NULL); 1860 } 1861 1862 static bool 1863 are_members_compatible(const sym_t *a, const sym_t *b) 1864 { 1865 if (a->u.s_member.sm_offset_in_bits != b->u.s_member.sm_offset_in_bits) 1866 return false; 1867 1868 const type_t *atp = a->s_type; 1869 const type_t *btp = b->s_type; 1870 bool w = false; 1871 if (!types_compatible(atp, btp, false, false, &w) && !w) 1872 return false; 1873 if (a->s_bitfield != b->s_bitfield) 1874 return false; 1875 if (a->s_bitfield) { 1876 if (atp->t_bit_field_width != btp->t_bit_field_width) 1877 return false; 1878 if (atp->t_bit_field_offset != btp->t_bit_field_offset) 1879 return false; 1880 } 1881 return true; 1882 } 1883 1884 /* 1885 * Return whether all struct/union members with the same name have the same 1886 * type and offset. 1887 */ 1888 static bool 1889 all_members_compatible(const sym_t *msym) 1890 { 1891 for (const sym_t *csym = msym; 1892 csym != NULL; csym = csym->s_symtab_next) { 1893 if (!is_member(csym)) 1894 continue; 1895 if (strcmp(msym->s_name, csym->s_name) != 0) 1896 continue; 1897 1898 for (const sym_t *sym = csym->s_symtab_next; 1899 sym != NULL; sym = sym->s_symtab_next) { 1900 if (is_member(sym) 1901 && strcmp(csym->s_name, sym->s_name) == 0 1902 && !are_members_compatible(csym, sym)) 1903 return false; 1904 } 1905 } 1906 return true; 1907 } 1908 1909 sym_t * 1910 find_member(const struct_or_union *sou, const char *name) 1911 { 1912 for (sym_t *mem = sou->sou_first_member; 1913 mem != NULL; mem = mem->s_next) { 1914 lint_assert(is_member(mem)); 1915 lint_assert(mem->u.s_member.sm_containing_type == sou); 1916 if (strcmp(mem->s_name, name) == 0) 1917 return mem; 1918 } 1919 1920 for (sym_t *mem = sou->sou_first_member; 1921 mem != NULL; mem = mem->s_next) { 1922 if (is_struct_or_union(mem->s_type->t_tspec) 1923 && mem->s_name == unnamed) { 1924 sym_t *nested_mem = 1925 find_member(mem->s_type->t_sou, name); 1926 if (nested_mem != NULL) 1927 return nested_mem; 1928 } 1929 } 1930 return NULL; 1931 } 1932 1933 /* 1934 * Remove the member if it was unknown until now, which means 1935 * that no defined struct or union has a member with the same name. 1936 */ 1937 static void 1938 remove_unknown_member(tnode_t *tn, sym_t *msym) 1939 { 1940 /* type '%s' does not have member '%s' */ 1941 error(101, type_name(tn->tn_type), msym->s_name); 1942 rmsym(msym); 1943 msym->s_kind = FMEMBER; 1944 msym->s_scl = STRUCT_MEMBER; 1945 1946 struct_or_union *sou = expr_zero_alloc(sizeof(*sou), 1947 "struct_or_union"); 1948 sou->sou_tag = expr_zero_alloc(sizeof(*sou->sou_tag), "sym"); 1949 sou->sou_tag->s_name = unnamed; 1950 1951 msym->u.s_member.sm_containing_type = sou; 1952 /* 1953 * The member sm_offset_in_bits is not needed here since this symbol 1954 * can only be used for error reporting. 1955 */ 1956 } 1957 1958 /* 1959 * Returns a symbol which has the same name as 'msym' and is a member of the 1960 * struct or union specified by 'tn'. 1961 */ 1962 static sym_t * 1963 struct_or_union_member(tnode_t *tn, op_t op, sym_t *msym) 1964 { 1965 1966 /* Determine the tag type of which msym is expected to be a member. */ 1967 const type_t *tp = NULL; 1968 if (op == POINT && is_struct_or_union(tn->tn_type->t_tspec)) 1969 tp = tn->tn_type; 1970 if (op == ARROW && tn->tn_type->t_tspec == PTR 1971 && is_struct_or_union(tn->tn_type->t_subt->t_tspec)) 1972 tp = tn->tn_type->t_subt; 1973 struct_or_union *sou = tp != NULL ? tp->t_sou : NULL; 1974 1975 if (sou != NULL) { 1976 sym_t *nested_mem = find_member(sou, msym->s_name); 1977 if (nested_mem != NULL) 1978 return nested_mem; 1979 } 1980 1981 if (msym->s_scl == NO_SCL) { 1982 remove_unknown_member(tn, msym); 1983 return msym; 1984 } 1985 1986 bool eq = all_members_compatible(msym); 1987 1988 /* 1989 * Now handle the case in which the left operand refers really to a 1990 * struct/union, but the right operand is not member of it. 1991 */ 1992 if (sou != NULL) { 1993 if (eq && !allow_c90) { 1994 /* illegal use of member '%s' */ 1995 warning(102, msym->s_name); 1996 } else { 1997 /* illegal use of member '%s' */ 1998 error(102, msym->s_name); 1999 } 2000 return msym; 2001 } 2002 2003 /* 2004 * Now the left operand of ARROW does not point to a struct/union or 2005 * the left operand of POINT is no struct/union. 2006 */ 2007 if (eq) { 2008 if (op == POINT) { 2009 if (!allow_c90) { 2010 /* left operand of '.' must be struct ... */ 2011 warning(103, type_name(tn->tn_type)); 2012 } else { 2013 /* left operand of '.' must be struct ... */ 2014 error(103, type_name(tn->tn_type)); 2015 } 2016 } else { 2017 if (!allow_c90 && tn->tn_type->t_tspec == PTR) { 2018 /* left operand of '->' must be pointer ... */ 2019 warning(104, type_name(tn->tn_type)); 2020 } else { 2021 /* left operand of '->' must be pointer ... */ 2022 error(104, type_name(tn->tn_type)); 2023 } 2024 } 2025 } else { 2026 if (!allow_c90) { 2027 /* non-unique member requires struct/union %s */ 2028 error(105, op == POINT ? "object" : "pointer"); 2029 } else { 2030 /* unacceptable operand of '%s' */ 2031 error(111, op_name(op)); 2032 } 2033 } 2034 2035 return msym; 2036 } 2037 2038 tnode_t * 2039 build_member_access(tnode_t *ln, op_t op, bool sys, sbuf_t *member) 2040 { 2041 sym_t *msym; 2042 2043 if (ln == NULL) 2044 return NULL; 2045 2046 if (op == ARROW) { 2047 /* must do this before struct_or_union_member is called */ 2048 ln = cconv(ln); 2049 } 2050 msym = struct_or_union_member(ln, op, getsym(member)); 2051 return build_binary(ln, op, sys, build_name(msym, false)); 2052 } 2053 2054 /* 2055 * Perform class conversions. 2056 * 2057 * Arrays of type T are converted into pointers to type T. 2058 * Functions are converted to pointers to functions. 2059 * Lvalues are converted to rvalues. 2060 * 2061 * C99 6.3 "Conversions" 2062 * C99 6.3.2 "Other operands" 2063 * C99 6.3.2.1 "Lvalues, arrays, and function designators" 2064 */ 2065 tnode_t * 2066 cconv(tnode_t *tn) 2067 { 2068 /* 2069 * Array-lvalue (array of type T) is converted into rvalue (pointer to 2070 * type T) 2071 */ 2072 if (tn->tn_type->t_tspec == ARRAY) { 2073 if (!tn->tn_lvalue) { 2074 /* XXX print correct operator */ 2075 /* %soperand of '%s' must be lvalue */ 2076 gnuism(114, "", op_name(ADDR)); 2077 } 2078 tn = build_op(ADDR, tn->tn_sys, 2079 expr_derive_type(tn->tn_type->t_subt, PTR), tn, NULL); 2080 } 2081 2082 /* 2083 * Expression of type function (function with return value of type T) 2084 * in rvalue-expression (pointer to function with return value of type 2085 * T) 2086 */ 2087 if (tn->tn_type->t_tspec == FUNC) 2088 tn = build_address(tn->tn_sys, tn, true); 2089 2090 /* lvalue to rvalue */ 2091 if (tn->tn_lvalue) { 2092 type_t *tp = expr_dup_type(tn->tn_type); 2093 /* C99 6.3.2.1p2 sentence 2 says to remove the qualifiers. */ 2094 tp->t_const = tp->t_volatile = false; 2095 tn = build_op(LOAD, tn->tn_sys, tp, tn, NULL); 2096 } 2097 2098 return tn; 2099 } 2100 2101 const tnode_t * 2102 before_conversion(const tnode_t *tn) 2103 { 2104 while (tn->tn_op == CVT && !tn->tn_cast) 2105 tn = tn->tn_left; 2106 return tn; 2107 } 2108 2109 /* 2110 * Most errors required by C90 are reported in struct_or_union_member(). 2111 * Here we only check for totally wrong things. 2112 */ 2113 static bool 2114 typeok_point(const tnode_t *ln, const type_t *ltp, tspec_t lt) 2115 { 2116 if (is_struct_or_union(lt)) 2117 return true; 2118 2119 if (lt == FUNC || lt == VOID || ltp->t_bitfield) 2120 goto wrong; 2121 2122 /* 2123 * Some C dialects from before C90 tolerated any lvalue on the 2124 * left-hand side of the '.' operator, allowing things like 'char 2125 * st[100]; st.st_mtime', assuming that the member 'st_mtime' only 2126 * occurred in a single struct; see typeok_arrow. 2127 */ 2128 if (ln->tn_lvalue) 2129 return true; 2130 2131 wrong: 2132 /* With allow_c90 we already got an error */ 2133 if (!allow_c90) 2134 /* unacceptable operand of '%s' */ 2135 error(111, op_name(POINT)); 2136 2137 return false; 2138 } 2139 2140 static bool 2141 typeok_arrow(tspec_t lt) 2142 { 2143 /* 2144 * C1978 Appendix A 14.1 says: <quote>In fact, any lvalue is allowed 2145 * before '.', and that lvalue is then assumed to have the form of the 2146 * structure of which the name of the right is a member. [...] Such 2147 * constructions are non-portable.</quote> 2148 */ 2149 if (lt == PTR || (!allow_c90 && is_integer(lt))) 2150 return true; 2151 2152 /* With allow_c90 we already got an error */ 2153 if (!allow_c90) 2154 /* unacceptable operand of '%s' */ 2155 error(111, op_name(ARROW)); 2156 return false; 2157 } 2158 2159 static bool 2160 typeok_incdec(op_t op, const tnode_t *tn, const type_t *tp) 2161 { 2162 /* operand has scalar type (checked in typeok) */ 2163 if (!tn->tn_lvalue) { 2164 if (tn->tn_op == CVT && tn->tn_cast && 2165 tn->tn_left->tn_op == LOAD) { 2166 /* a cast does not yield an lvalue */ 2167 error(163); 2168 } 2169 /* %soperand of '%s' must be lvalue */ 2170 error(114, "", op_name(op)); 2171 return false; 2172 } 2173 if (tp->t_const && allow_c90) { 2174 /* %soperand of '%s' must be modifiable lvalue */ 2175 warning(115, "", op_name(op)); 2176 } 2177 return true; 2178 } 2179 2180 static bool 2181 typeok_address(op_t op, const tnode_t *tn, const type_t *tp, tspec_t t) 2182 { 2183 if (t == ARRAY || t == FUNC) { 2184 /* ok, a warning comes later (in build_address()) */ 2185 } else if (!tn->tn_lvalue) { 2186 if (tn->tn_op == CVT && tn->tn_cast && 2187 tn->tn_left->tn_op == LOAD) { 2188 /* a cast does not yield an lvalue */ 2189 error(163); 2190 } 2191 /* %soperand of '%s' must be lvalue */ 2192 error(114, "", op_name(op)); 2193 return false; 2194 } else if (is_scalar(t)) { 2195 if (tp->t_bitfield) { 2196 /* cannot take address of bit-field */ 2197 error(112); 2198 return false; 2199 } 2200 } else if (t != STRUCT && t != UNION) { 2201 /* unacceptable operand of '%s' */ 2202 error(111, op_name(op)); 2203 return false; 2204 } 2205 if (tn->tn_op == NAME && tn->tn_sym->s_register) { 2206 /* cannot take address of register '%s' */ 2207 error(113, tn->tn_sym->s_name); 2208 return false; 2209 } 2210 return true; 2211 } 2212 2213 static bool 2214 typeok_indir(const type_t *tp, tspec_t t) 2215 { 2216 2217 if (t != PTR) { 2218 /* cannot dereference non-pointer type '%s' */ 2219 error(96, type_name(tp)); 2220 return false; 2221 } 2222 return true; 2223 } 2224 2225 static void 2226 warn_incompatible_types(op_t op, 2227 const type_t *ltp, tspec_t lt, 2228 const type_t *rtp, tspec_t rt) 2229 { 2230 bool binary = modtab[op].m_binary; 2231 2232 if (lt == VOID || (binary && rt == VOID)) { 2233 /* void type illegal in expression */ 2234 error(109); 2235 } else if (op == ASSIGN) { 2236 /* cannot assign to '%s' from '%s' */ 2237 error(171, type_name(ltp), type_name(rtp)); 2238 } else if (binary) { 2239 /* operands of '%s' have incompatible types '%s' and '%s' */ 2240 error(107, op_name(op), type_name(ltp), type_name(rtp)); 2241 } else { 2242 lint_assert(rt == NO_TSPEC); 2243 /* operand of '%s' has invalid type '%s' */ 2244 error(108, op_name(op), type_name(ltp)); 2245 } 2246 } 2247 2248 static bool 2249 typeok_plus(op_t op, 2250 const type_t *ltp, tspec_t lt, 2251 const type_t *rtp, tspec_t rt) 2252 { 2253 /* operands have scalar types (checked in typeok) */ 2254 if ((lt == PTR && !is_integer(rt)) || (rt == PTR && !is_integer(lt))) { 2255 warn_incompatible_types(op, ltp, lt, rtp, rt); 2256 return false; 2257 } 2258 return true; 2259 } 2260 2261 static bool 2262 typeok_minus(op_t op, 2263 const type_t *ltp, tspec_t lt, 2264 const type_t *rtp, tspec_t rt) 2265 { 2266 /* operands have scalar types (checked in typeok) */ 2267 if ((lt == PTR && rt != PTR && !is_integer(rt)) || 2268 (lt != PTR && rt == PTR)) { 2269 warn_incompatible_types(op, ltp, lt, rtp, rt); 2270 return false; 2271 } 2272 if (lt == PTR && rt == PTR && 2273 !types_compatible(ltp->t_subt, rtp->t_subt, true, false, NULL)) { 2274 /* illegal pointer subtraction */ 2275 error(116); 2276 } 2277 return true; 2278 } 2279 2280 static void 2281 typeok_shr(op_t op, 2282 const tnode_t *ln, tspec_t lt, 2283 const tnode_t *rn, tspec_t rt) 2284 { 2285 tspec_t olt = before_conversion(ln)->tn_type->t_tspec; 2286 tspec_t ort = before_conversion(rn)->tn_type->t_tspec; 2287 2288 /* operands have integer types (checked in typeok) */ 2289 if (pflag && !is_uinteger(olt)) { 2290 integer_constraints lc = ic_expr(ln); 2291 if (!ic_maybe_signed(ln->tn_type, &lc)) 2292 return; 2293 2294 /* 2295 * The left operand is signed. This means that the operation is 2296 * (possibly) nonportable. 2297 */ 2298 if (ln->tn_op != CON) { 2299 /* bitwise '%s' on signed value possibly nonportable */ 2300 warning(117, op_name(op)); 2301 } else if (ln->tn_val.u.integer < 0) { 2302 /* bitwise '%s' on signed value nonportable */ 2303 warning(120, op_name(op)); 2304 } 2305 } else if (allow_trad && allow_c90 && 2306 !is_uinteger(olt) && is_uinteger(ort)) { 2307 /* The left operand would become unsigned in traditional C. */ 2308 if (hflag && (ln->tn_op != CON || ln->tn_val.u.integer < 0)) { 2309 /* semantics of '%s' change in C90; use ... */ 2310 warning(118, op_name(op)); 2311 } 2312 } else if (allow_trad && allow_c90 && 2313 !is_uinteger(olt) && !is_uinteger(ort) && 2314 portable_rank_cmp(lt, rt) < 0) { 2315 /* 2316 * In traditional C, the left operand would be extended 2317 * (possibly sign-extended) and then shifted. 2318 */ 2319 if (hflag && (ln->tn_op != CON || ln->tn_val.u.integer < 0)) { 2320 /* semantics of '%s' change in C90; use ... */ 2321 warning(118, op_name(op)); 2322 } 2323 } 2324 } 2325 2326 static void 2327 typeok_shl(op_t op, tspec_t lt, tspec_t rt) 2328 { 2329 /* 2330 * C90 does not perform balancing for shift operations, but traditional 2331 * C does. If the width of the right operand is greater than the width 2332 * of the left operand, then in traditional C the left operand would be 2333 * extended to the width of the right operand. For SHL this may result 2334 * in different results. 2335 */ 2336 if (portable_rank_cmp(lt, rt) < 0) { 2337 /* 2338 * XXX If both operands are constant, make sure that there is 2339 * really a difference between C90 and traditional C. 2340 */ 2341 if (hflag && allow_trad && allow_c90) 2342 /* semantics of '%s' change in C90; use ... */ 2343 warning(118, op_name(op)); 2344 } 2345 } 2346 2347 static void 2348 typeok_shift(const type_t *ltp, tspec_t lt, const tnode_t *rn, tspec_t rt) 2349 { 2350 if (rn->tn_op != CON) 2351 return; 2352 2353 if (!is_uinteger(rt) && rn->tn_val.u.integer < 0) { 2354 /* negative shift */ 2355 warning(121); 2356 } else if ((uint64_t)rn->tn_val.u.integer == size_in_bits(lt)) { 2357 /* shift amount %u equals bit-size of '%s' */ 2358 warning(267, (unsigned)rn->tn_val.u.integer, type_name(ltp)); 2359 } else if ((uint64_t)rn->tn_val.u.integer > size_in_bits(lt)) { 2360 /* shift amount %llu is greater than bit-size %llu of '%s' */ 2361 warning(122, (unsigned long long)rn->tn_val.u.integer, 2362 (unsigned long long)size_in_bits(lt), 2363 tspec_name(lt)); 2364 } 2365 } 2366 2367 static bool 2368 is_typeok_eq(const tnode_t *ln, tspec_t lt, const tnode_t *rn, tspec_t rt) 2369 { 2370 if (lt == PTR && is_null_pointer(rn)) 2371 return true; 2372 if (rt == PTR && is_null_pointer(ln)) 2373 return true; 2374 return false; 2375 } 2376 2377 /* 2378 * Called if incompatible pointer types are detected. 2379 * Print an appropriate warning. 2380 */ 2381 static void 2382 warn_incompatible_pointers(op_t op, const type_t *ltp, const type_t *rtp) 2383 { 2384 lint_assert(ltp->t_tspec == PTR); 2385 lint_assert(rtp->t_tspec == PTR); 2386 2387 tspec_t lt = ltp->t_subt->t_tspec; 2388 tspec_t rt = rtp->t_subt->t_tspec; 2389 2390 if (is_struct_or_union(lt) && is_struct_or_union(rt)) { 2391 if (op == RETURN) { 2392 /* illegal structure pointer combination */ 2393 warning(244); 2394 } else { 2395 /* incompatible structure pointers: '%s' '%s' '%s' */ 2396 warning(245, type_name(ltp), 2397 op_name(op), type_name(rtp)); 2398 } 2399 } else { 2400 if (op == RETURN) { 2401 /* illegal combination of '%s' and '%s' */ 2402 warning(184, type_name(ltp), type_name(rtp)); 2403 } else { 2404 /* illegal combination of '%s' and '%s', op '%s' */ 2405 warning(124, 2406 type_name(ltp), type_name(rtp), op_name(op)); 2407 } 2408 } 2409 } 2410 2411 static void 2412 check_pointer_comparison(op_t op, const tnode_t *ln, const tnode_t *rn) 2413 { 2414 type_t *ltp = ln->tn_type, *rtp = rn->tn_type; 2415 tspec_t lst = ltp->t_subt->t_tspec, rst = rtp->t_subt->t_tspec; 2416 2417 if (lst == VOID || rst == VOID) { 2418 /* TODO: C99 behaves like C90 here. */ 2419 if ((!allow_trad && !allow_c99) && 2420 (lst == FUNC || rst == FUNC)) { 2421 /* (void *)0 is already handled in typeok() */ 2422 const char *lsts, *rsts; 2423 *(lst == FUNC ? &lsts : &rsts) = "function pointer"; 2424 *(lst == VOID ? &lsts : &rsts) = "'void *'"; 2425 /* C90 or later forbid comparison of %s with %s */ 2426 warning(274, lsts, rsts); 2427 } 2428 return; 2429 } 2430 2431 if (!types_compatible(ltp->t_subt, rtp->t_subt, true, false, NULL)) { 2432 warn_incompatible_pointers(op, ltp, rtp); 2433 return; 2434 } 2435 2436 if (lst == FUNC && rst == FUNC) { 2437 /* TODO: C99 behaves like C90 here, see C99 6.5.8p2. */ 2438 if ((!allow_trad && !allow_c99) && op != EQ && op != NE) 2439 /* pointers to functions can only be compared ... */ 2440 warning(125); 2441 } 2442 } 2443 2444 static bool 2445 typeok_compare(op_t op, 2446 const tnode_t *ln, const type_t *ltp, tspec_t lt, 2447 const tnode_t *rn, const type_t *rtp, tspec_t rt) 2448 { 2449 if (lt == PTR && rt == PTR) { 2450 check_pointer_comparison(op, ln, rn); 2451 return true; 2452 } 2453 2454 if (lt != PTR && rt != PTR) 2455 return true; 2456 2457 if (!is_integer(lt) && !is_integer(rt)) { 2458 warn_incompatible_types(op, ltp, lt, rtp, rt); 2459 return false; 2460 } 2461 2462 const char *lx = lt == PTR ? "pointer" : "integer"; 2463 const char *rx = rt == PTR ? "pointer" : "integer"; 2464 /* illegal combination of %s '%s' and %s '%s', op '%s' */ 2465 warning(123, lx, type_name(ltp), rx, type_name(rtp), op_name(op)); 2466 return true; 2467 } 2468 2469 static bool 2470 typeok_quest(tspec_t lt, const tnode_t *rn) 2471 { 2472 if (!is_scalar(lt)) { 2473 /* first operand of '?' must have scalar type */ 2474 error(170); 2475 return false; 2476 } 2477 lint_assert(before_conversion(rn)->tn_op == COLON); 2478 return true; 2479 } 2480 2481 static void 2482 typeok_colon_pointer(const type_t *ltp, const type_t *rtp) 2483 { 2484 type_t *lstp = ltp->t_subt; 2485 type_t *rstp = rtp->t_subt; 2486 tspec_t lst = lstp->t_tspec; 2487 tspec_t rst = rstp->t_tspec; 2488 2489 if ((lst == VOID && rst == FUNC) || (lst == FUNC && rst == VOID)) { 2490 /* (void *)0 is handled in typeok_colon */ 2491 /* TODO: C99 behaves like C90 here. */ 2492 if (!allow_trad && !allow_c99) 2493 /* conversion of %s to %s requires a cast, op %s */ 2494 warning(305, "function pointer", "'void *'", 2495 op_name(COLON)); 2496 return; 2497 } 2498 2499 if (pointer_types_are_compatible(lstp, rstp, true)) 2500 return; 2501 if (!types_compatible(lstp, rstp, true, false, NULL)) 2502 warn_incompatible_pointers(COLON, ltp, rtp); 2503 } 2504 2505 static bool 2506 typeok_colon(const tnode_t *ln, const type_t *ltp, tspec_t lt, 2507 const tnode_t *rn, const type_t *rtp, tspec_t rt) 2508 { 2509 2510 if (is_arithmetic(lt) && is_arithmetic(rt)) 2511 return true; 2512 if (lt == BOOL && rt == BOOL) 2513 return true; 2514 2515 if (lt == STRUCT && rt == STRUCT && ltp->t_sou == rtp->t_sou) 2516 return true; 2517 if (lt == UNION && rt == UNION && ltp->t_sou == rtp->t_sou) 2518 return true; 2519 2520 if (lt == PTR && is_null_pointer(rn)) 2521 return true; 2522 if (rt == PTR && is_null_pointer(ln)) 2523 return true; 2524 2525 if ((lt == PTR && is_integer(rt)) || (is_integer(lt) && rt == PTR)) { 2526 const char *lx = lt == PTR ? "pointer" : "integer"; 2527 const char *rx = rt == PTR ? "pointer" : "integer"; 2528 /* illegal combination of %s '%s' and %s '%s', op '%s' */ 2529 warning(123, lx, type_name(ltp), 2530 rx, type_name(rtp), op_name(COLON)); 2531 return true; 2532 } 2533 2534 if (lt == VOID || rt == VOID) { 2535 if (lt != VOID || rt != VOID) 2536 /* incompatible types '%s' and '%s' in conditional */ 2537 warning(126, type_name(ltp), type_name(rtp)); 2538 return true; 2539 } 2540 2541 if (lt == PTR && rt == PTR) { 2542 typeok_colon_pointer(ltp, rtp); 2543 return true; 2544 } 2545 2546 /* incompatible types '%s' and '%s' in conditional */ 2547 error(126, type_name(ltp), type_name(rtp)); 2548 return false; 2549 } 2550 2551 /* 2552 * Returns true if the given structure or union has a constant member 2553 * (maybe recursively). 2554 */ 2555 static bool 2556 has_constant_member(const type_t *tp) 2557 { 2558 lint_assert(is_struct_or_union(tp->t_tspec)); 2559 2560 for (sym_t *m = tp->t_sou->sou_first_member; 2561 m != NULL; m = m->s_next) { 2562 const type_t *mtp = m->s_type; 2563 if (mtp->t_const) 2564 return true; 2565 if (is_struct_or_union(mtp->t_tspec) && 2566 has_constant_member(mtp)) 2567 return true; 2568 } 2569 return false; 2570 } 2571 2572 static bool 2573 typeok_assign(op_t op, const tnode_t *ln, const type_t *ltp, tspec_t lt) 2574 { 2575 if (op == RETURN || op == INIT || op == FARG) 2576 return true; 2577 2578 if (!ln->tn_lvalue) { 2579 if (ln->tn_op == CVT && ln->tn_cast && 2580 ln->tn_left->tn_op == LOAD) { 2581 /* a cast does not yield an lvalue */ 2582 error(163); 2583 } 2584 /* %soperand of '%s' must be lvalue */ 2585 error(114, "left ", op_name(op)); 2586 return false; 2587 } else if (ltp->t_const 2588 || (is_struct_or_union(lt) && has_constant_member(ltp))) { 2589 if (allow_c90) 2590 /* %soperand of '%s' must be modifiable lvalue */ 2591 warning(115, "left ", op_name(op)); 2592 } 2593 return true; 2594 } 2595 2596 /* Check the types using the information from modtab[]. */ 2597 static bool 2598 typeok_scalar(op_t op, const mod_t *mp, 2599 const type_t *ltp, tspec_t lt, 2600 const type_t *rtp, tspec_t rt) 2601 { 2602 if (mp->m_takes_bool && lt == BOOL && rt == BOOL) 2603 return true; 2604 if (mp->m_requires_integer) { 2605 if (!is_integer(lt) || (mp->m_binary && !is_integer(rt))) { 2606 warn_incompatible_types(op, ltp, lt, rtp, rt); 2607 return false; 2608 } 2609 } else if (mp->m_requires_integer_or_complex) { 2610 if ((!is_integer(lt) && !is_complex(lt)) || 2611 (mp->m_binary && (!is_integer(rt) && !is_complex(rt)))) { 2612 warn_incompatible_types(op, ltp, lt, rtp, rt); 2613 return false; 2614 } 2615 } else if (mp->m_requires_scalar) { 2616 if (!is_scalar(lt) || (mp->m_binary && !is_scalar(rt))) { 2617 warn_incompatible_types(op, ltp, lt, rtp, rt); 2618 return false; 2619 } 2620 } else if (mp->m_requires_arith) { 2621 if (!is_arithmetic(lt) || 2622 (mp->m_binary && !is_arithmetic(rt))) { 2623 warn_incompatible_types(op, ltp, lt, rtp, rt); 2624 return false; 2625 } 2626 } 2627 return true; 2628 } 2629 2630 static void 2631 check_assign_void_pointer(op_t op, int arg, 2632 tspec_t lt, tspec_t lst, 2633 tspec_t rt, tspec_t rst) 2634 { 2635 2636 if (!(lt == PTR && rt == PTR && (lst == VOID || rst == VOID))) 2637 return; 2638 /* two pointers, at least one pointer to void */ 2639 2640 /* TODO: C99 behaves like C90 here. */ 2641 if (!((!allow_trad && !allow_c99) && (lst == FUNC || rst == FUNC))) 2642 return; 2643 /* comb. of ptr to func and ptr to void */ 2644 2645 const char *lts, *rts; 2646 *(lst == FUNC ? <s : &rts) = "function pointer"; 2647 *(lst == VOID ? <s : &rts) = "'void *'"; 2648 2649 switch (op) { 2650 case INIT: 2651 case RETURN: 2652 /* conversion of %s to %s requires a cast */ 2653 warning(303, rts, lts); 2654 break; 2655 case FARG: 2656 /* conversion of %s to %s requires a cast, arg #%d */ 2657 warning(304, rts, lts, arg); 2658 break; 2659 default: 2660 /* conversion of %s to %s requires a cast, op %s */ 2661 warning(305, rts, lts, op_name(op)); 2662 break; 2663 } 2664 } 2665 2666 static bool 2667 is_direct_function_call(const tnode_t *tn, const char **out_name) 2668 { 2669 2670 if (!(tn->tn_op == CALL && 2671 tn->tn_left->tn_op == ADDR && 2672 tn->tn_left->tn_left->tn_op == NAME)) 2673 return false; 2674 2675 *out_name = tn->tn_left->tn_left->tn_sym->s_name; 2676 return true; 2677 } 2678 2679 static bool 2680 is_unconst_function(const char *name) 2681 { 2682 2683 return strcmp(name, "memchr") == 0 || 2684 strcmp(name, "strchr") == 0 || 2685 strcmp(name, "strpbrk") == 0 || 2686 strcmp(name, "strrchr") == 0 || 2687 strcmp(name, "strstr") == 0; 2688 } 2689 2690 static bool 2691 is_const_char_pointer(const tnode_t *tn) 2692 { 2693 /* 2694 * For traditional reasons, C99 6.4.5p5 defines that string literals 2695 * have type 'char[]'. They are often implicitly converted to 'char 2696 * *', for example when they are passed as function arguments. 2697 * 2698 * C99 6.4.5p6 further defines that modifying a string that is 2699 * constructed from a string literal invokes undefined behavior. 2700 * 2701 * Out of these reasons, string literals are treated as 'effectively 2702 * const' here. 2703 */ 2704 if (tn->tn_op == CVT && 2705 tn->tn_left->tn_op == ADDR && 2706 tn->tn_left->tn_left->tn_op == STRING) 2707 return true; 2708 2709 const type_t *tp = before_conversion(tn)->tn_type; 2710 return tp->t_tspec == PTR && 2711 tp->t_subt->t_tspec == CHAR && 2712 tp->t_subt->t_const; 2713 } 2714 2715 static bool 2716 is_first_arg_const_char_pointer(const tnode_t *tn) 2717 { 2718 lint_assert(has_operands(tn)); 2719 const tnode_t *an = tn->tn_right; 2720 if (an == NULL) 2721 return false; 2722 2723 while (tn_ck_right(an) != NULL) 2724 an = an->tn_right; 2725 return is_const_char_pointer(an->tn_left); 2726 } 2727 2728 static bool 2729 is_const_pointer(const tnode_t *tn) 2730 { 2731 const type_t *tp = before_conversion(tn)->tn_type; 2732 return tp->t_tspec == PTR && tp->t_subt->t_const; 2733 } 2734 2735 static bool 2736 is_second_arg_const_pointer(const tnode_t *tn) 2737 { 2738 const tnode_t *an = tn_ck_right(tn); 2739 if (an == NULL || tn_ck_right(an) == NULL) 2740 return false; 2741 2742 while (tn_ck_right(an->tn_right) != NULL) 2743 an = an->tn_right; 2744 return is_const_pointer(an->tn_left); 2745 } 2746 2747 static void 2748 check_unconst_function(const type_t *lstp, const tnode_t *rn) 2749 { 2750 const char *function_name; 2751 2752 if (lstp->t_tspec == CHAR && !lstp->t_const && 2753 is_direct_function_call(rn, &function_name) && 2754 is_unconst_function(function_name) && 2755 is_first_arg_const_char_pointer(rn)) { 2756 /* call to '%s' effectively discards 'const' from argument */ 2757 warning(346, function_name); 2758 } 2759 2760 if (!lstp->t_const && 2761 is_direct_function_call(rn, &function_name) && 2762 strcmp(function_name, "bsearch") == 0 && 2763 is_second_arg_const_pointer(rn)) { 2764 /* call to '%s' effectively discards 'const' from argument */ 2765 warning(346, function_name); 2766 } 2767 } 2768 2769 static bool 2770 check_assign_void_pointer_compat(op_t op, int arg, 2771 const type_t *const ltp, tspec_t const lt, 2772 const type_t *const lstp, tspec_t const lst, 2773 const tnode_t *const rn, 2774 const type_t *const rtp, tspec_t const rt, 2775 const type_t *const rstp, tspec_t const rst) 2776 { 2777 if (!(lt == PTR && rt == PTR && (lst == VOID || rst == VOID || 2778 types_compatible(lstp, rstp, 2779 true, false, NULL)))) 2780 return false; 2781 2782 /* compatible pointer types (qualifiers ignored) */ 2783 if (allow_c90 && 2784 ((!lstp->t_const && rstp->t_const) || 2785 (!lstp->t_volatile && rstp->t_volatile))) { 2786 /* left side has not all qualifiers of right */ 2787 switch (op) { 2788 case INIT: 2789 case RETURN: 2790 /* incompatible pointer types to '%s' and '%s' */ 2791 warning(182, type_name(lstp), type_name(rstp)); 2792 break; 2793 case FARG: 2794 /* converting '%s' to incompatible '%s' ... */ 2795 warning(153, 2796 type_name(rtp), type_name(ltp), arg); 2797 break; 2798 default: 2799 /* operands of '%s' have incompatible pointer ... */ 2800 warning(128, op_name(op), 2801 type_name(lstp), type_name(rstp)); 2802 break; 2803 } 2804 } 2805 2806 if (allow_c90) 2807 check_unconst_function(lstp, rn); 2808 2809 return true; 2810 } 2811 2812 static bool 2813 check_assign_pointer_integer(op_t op, int arg, 2814 const type_t *const ltp, tspec_t const lt, 2815 const type_t *const rtp, tspec_t const rt) 2816 { 2817 2818 if (!((lt == PTR && is_integer(rt)) || (is_integer(lt) && rt == PTR))) 2819 return false; 2820 2821 const char *lx = lt == PTR ? "pointer" : "integer"; 2822 const char *rx = rt == PTR ? "pointer" : "integer"; 2823 2824 switch (op) { 2825 case INIT: 2826 case RETURN: 2827 /* illegal combination of %s '%s' and %s '%s' */ 2828 warning(183, lx, type_name(ltp), rx, type_name(rtp)); 2829 break; 2830 case FARG: 2831 /* illegal combination of %s '%s' and %s '%s', arg #%d */ 2832 warning(154, 2833 lx, type_name(ltp), rx, type_name(rtp), arg); 2834 break; 2835 default: 2836 /* illegal combination of %s '%s' and %s '%s', op '%s' */ 2837 warning(123, 2838 lx, type_name(ltp), rx, type_name(rtp), op_name(op)); 2839 break; 2840 } 2841 return true; 2842 } 2843 2844 static bool 2845 check_assign_pointer(op_t op, int arg, 2846 const type_t *ltp, tspec_t lt, 2847 const type_t *rtp, tspec_t rt) 2848 { 2849 if (!(lt == PTR && rt == PTR)) 2850 return false; 2851 2852 if (op == FARG) 2853 /* converting '%s' to incompatible '%s' for ... */ 2854 warning(153, type_name(rtp), type_name(ltp), arg); 2855 else 2856 warn_incompatible_pointers(op, ltp, rtp); 2857 return true; 2858 } 2859 2860 static void 2861 warn_assign(op_t op, int arg, 2862 const type_t *ltp, tspec_t lt, 2863 const type_t *rtp, tspec_t rt) 2864 { 2865 switch (op) { 2866 case INIT: 2867 /* cannot initialize '%s' from '%s' */ 2868 error(185, type_name(ltp), type_name(rtp)); 2869 break; 2870 case RETURN: 2871 /* function has return type '%s' but returns '%s' */ 2872 error(211, type_name(ltp), type_name(rtp)); 2873 break; 2874 case FARG: 2875 /* passing '%s' to incompatible '%s', arg #%d */ 2876 warning(155, type_name(rtp), type_name(ltp), arg); 2877 break; 2878 default: 2879 warn_incompatible_types(op, ltp, lt, rtp, rt); 2880 break; 2881 } 2882 } 2883 2884 /* 2885 * Checks type compatibility for ASSIGN, INIT, FARG and RETURN 2886 * and prints warnings/errors if necessary. 2887 * Returns whether the types are (almost) compatible. 2888 */ 2889 static bool 2890 check_assign_types_compatible(op_t op, int arg, 2891 const tnode_t *ln, const tnode_t *rn) 2892 { 2893 tspec_t lt, rt, lst = NO_TSPEC, rst = NO_TSPEC; 2894 type_t *ltp, *rtp, *lstp = NULL, *rstp = NULL; 2895 2896 if ((lt = (ltp = ln->tn_type)->t_tspec) == PTR) 2897 lst = (lstp = ltp->t_subt)->t_tspec; 2898 if ((rt = (rtp = rn->tn_type)->t_tspec) == PTR) 2899 rst = (rstp = rtp->t_subt)->t_tspec; 2900 2901 if (lt == BOOL && is_scalar(rt)) /* C99 6.3.1.2 */ 2902 return true; 2903 2904 if (is_arithmetic(lt) && (is_arithmetic(rt) || rt == BOOL)) 2905 return true; 2906 2907 if (is_struct_or_union(lt) && is_struct_or_union(rt)) 2908 /* both are struct or union */ 2909 return ltp->t_sou == rtp->t_sou; 2910 2911 /* a null pointer may be assigned to any pointer */ 2912 if (lt == PTR && is_null_pointer(rn)) { 2913 if (is_integer(rn->tn_type->t_tspec)) 2914 /* implicit conversion from integer 0 to pointer ... */ 2915 query_message(15, type_name(ltp)); 2916 return true; 2917 } 2918 2919 check_assign_void_pointer(op, arg, lt, lst, rt, rst); 2920 2921 if (check_assign_void_pointer_compat(op, arg, 2922 ltp, lt, lstp, lst, rn, rtp, rt, rstp, rst)) 2923 return true; 2924 2925 if (check_assign_pointer_integer(op, arg, ltp, lt, rtp, rt)) 2926 return true; 2927 2928 if (check_assign_pointer(op, arg, ltp, lt, rtp, rt)) 2929 return true; 2930 2931 warn_assign(op, arg, ltp, lt, rtp, rt); 2932 return false; 2933 } 2934 2935 static bool 2936 has_side_effect(const tnode_t *tn) /* NOLINT(misc-no-recursion) */ 2937 { 2938 op_t op = tn->tn_op; 2939 2940 if (modtab[op].m_has_side_effect) 2941 return true; 2942 2943 if (op == CVT && tn->tn_type->t_tspec == VOID) 2944 return has_side_effect(tn->tn_left); 2945 2946 /* XXX: Why not has_side_effect(tn->tn_left) as well? */ 2947 if (op == LOGAND || op == LOGOR) 2948 return has_side_effect(tn->tn_right); 2949 2950 /* XXX: Why not has_side_effect(tn->tn_left) as well? */ 2951 if (op == QUEST) 2952 return has_side_effect(tn->tn_right); 2953 2954 if (op == COLON || op == COMMA) { 2955 return has_side_effect(tn->tn_left) || 2956 has_side_effect(tn->tn_right); 2957 } 2958 2959 return false; 2960 } 2961 2962 static bool 2963 is_void_cast(const tnode_t *tn) 2964 { 2965 2966 return tn->tn_op == CVT && tn->tn_cast && 2967 tn->tn_type->t_tspec == VOID; 2968 } 2969 2970 static bool 2971 is_local_symbol(const tnode_t *tn) 2972 { 2973 2974 return tn->tn_op == LOAD && 2975 tn->tn_left->tn_op == NAME && 2976 tn->tn_left->tn_sym->s_scl == AUTO; 2977 } 2978 2979 static bool 2980 is_int_constant_zero(const tnode_t *tn) 2981 { 2982 2983 return tn->tn_op == CON && 2984 tn->tn_type->t_tspec == INT && 2985 tn->tn_val.u.integer == 0; 2986 } 2987 2988 static void 2989 check_null_effect(const tnode_t *tn) 2990 { 2991 2992 if (hflag && 2993 !has_side_effect(tn) && 2994 !(is_void_cast(tn) && is_local_symbol(tn->tn_left)) && 2995 !(is_void_cast(tn) && is_int_constant_zero(tn->tn_left))) { 2996 /* expression has null effect */ 2997 warning(129); 2998 } 2999 } 3000 3001 /* 3002 * Check the types for specific operators and type combinations. 3003 * 3004 * At this point, the operands already conform to the type requirements of 3005 * the operator, such as being integer, floating or scalar. 3006 */ 3007 static bool 3008 typeok_op(op_t op, int arg, 3009 const tnode_t *ln, const type_t *ltp, tspec_t lt, 3010 const tnode_t *rn, const type_t *rtp, tspec_t rt) 3011 { 3012 switch (op) { 3013 case ARROW: 3014 return typeok_arrow(lt); 3015 case POINT: 3016 return typeok_point(ln, ltp, lt); 3017 case INCBEF: 3018 case DECBEF: 3019 case INCAFT: 3020 case DECAFT: 3021 return typeok_incdec(op, ln, ltp); 3022 case INDIR: 3023 return typeok_indir(ltp, lt); 3024 case ADDR: 3025 return typeok_address(op, ln, ltp, lt); 3026 case PLUS: 3027 return typeok_plus(op, ltp, lt, rtp, rt); 3028 case MINUS: 3029 return typeok_minus(op, ltp, lt, rtp, rt); 3030 case SHL: 3031 typeok_shl(op, lt, rt); 3032 goto shift; 3033 case SHR: 3034 typeok_shr(op, ln, lt, rn, rt); 3035 shift: 3036 typeok_shift(ltp, lt, rn, rt); 3037 break; 3038 case LT: 3039 case LE: 3040 case GT: 3041 case GE: 3042 compare: 3043 return typeok_compare(op, ln, ltp, lt, rn, rtp, rt); 3044 case EQ: 3045 case NE: 3046 if (is_typeok_eq(ln, lt, rn, rt)) 3047 break; 3048 goto compare; 3049 case QUEST: 3050 return typeok_quest(lt, rn); 3051 case COLON: 3052 return typeok_colon(ln, ltp, lt, rn, rtp, rt); 3053 case ASSIGN: 3054 case INIT: 3055 case FARG: 3056 case RETURN: 3057 if (!check_assign_types_compatible(op, arg, ln, rn)) 3058 return false; 3059 goto assign; 3060 case MULASS: 3061 case DIVASS: 3062 case MODASS: 3063 goto assign; 3064 case ADDASS: 3065 case SUBASS: 3066 if ((lt == PTR && !is_integer(rt)) || rt == PTR) { 3067 warn_incompatible_types(op, ltp, lt, rtp, rt); 3068 return false; 3069 } 3070 goto assign; 3071 case SHLASS: 3072 goto assign; 3073 case SHRASS: 3074 if (pflag && !is_uinteger(lt) && 3075 !(!allow_c90 && is_uinteger(rt))) { 3076 /* bitwise '%s' on signed value possibly nonportable */ 3077 warning(117, op_name(op)); 3078 } 3079 goto assign; 3080 case ANDASS: 3081 case XORASS: 3082 case ORASS: 3083 assign: 3084 return typeok_assign(op, ln, ltp, lt); 3085 case COMMA: 3086 if (!modtab[ln->tn_op].m_has_side_effect) 3087 check_null_effect(ln); 3088 break; 3089 default: 3090 break; 3091 } 3092 return true; 3093 } 3094 3095 /* Prints a warning if a strange operator is used on an enum type. */ 3096 static void 3097 check_bad_enum_operation(op_t op, const tnode_t *ln, const tnode_t *rn) 3098 { 3099 3100 if (!eflag) 3101 return; 3102 3103 /* Allow enum in array indices. */ 3104 if (op == PLUS && 3105 ((ln->tn_type->t_is_enum && rn->tn_type->t_tspec == PTR) || 3106 (rn->tn_type->t_is_enum && ln->tn_type->t_tspec == PTR))) { 3107 return; 3108 } 3109 3110 /* dubious operation '%s' on enum */ 3111 warning(241, op_name(op)); 3112 } 3113 3114 /* Prints a warning if an operator is applied to two different enum types. */ 3115 static void 3116 check_enum_type_mismatch(op_t op, int arg, const tnode_t *ln, const tnode_t *rn) 3117 { 3118 const mod_t *mp = &modtab[op]; 3119 3120 if (ln->tn_type->t_enum != rn->tn_type->t_enum) { 3121 switch (op) { 3122 case INIT: 3123 /* enum type mismatch between '%s' and '%s' in ... */ 3124 warning(210, 3125 type_name(ln->tn_type), type_name(rn->tn_type)); 3126 break; 3127 case FARG: 3128 /* function expects '%s', passing '%s' for arg #%d */ 3129 warning(156, 3130 type_name(ln->tn_type), type_name(rn->tn_type), 3131 arg); 3132 break; 3133 case RETURN: 3134 /* function has return type '%s' but returns '%s' */ 3135 warning(211, 3136 type_name(ln->tn_type), type_name(rn->tn_type)); 3137 break; 3138 default: 3139 /* enum type mismatch: '%s' '%s' '%s' */ 3140 warning(130, type_name(ln->tn_type), op_name(op), 3141 type_name(rn->tn_type)); 3142 break; 3143 } 3144 } else if (Pflag && eflag && mp->m_comparison && op != EQ && op != NE) 3145 /* operator '%s' assumes that '%s' is ordered */ 3146 warning(243, op_name(op), type_name(ln->tn_type)); 3147 } 3148 3149 /* Prints a warning if the operands mix between enum and integer. */ 3150 static void 3151 check_enum_int_mismatch(op_t op, int arg, const tnode_t *ln, const tnode_t *rn) 3152 { 3153 3154 if (!eflag) 3155 return; 3156 3157 switch (op) { 3158 case INIT: 3159 /* 3160 * Initialization with 0 is allowed. Otherwise, all implicit 3161 * initializations would need to be warned upon as well. 3162 */ 3163 if (!rn->tn_type->t_is_enum && rn->tn_op == CON && 3164 is_integer(rn->tn_type->t_tspec) && 3165 rn->tn_val.u.integer == 0) { 3166 return; 3167 } 3168 /* initialization of '%s' with '%s' */ 3169 warning(277, type_name(ln->tn_type), type_name(rn->tn_type)); 3170 break; 3171 case FARG: 3172 /* combination of '%s' and '%s', arg #%d */ 3173 warning(278, 3174 type_name(ln->tn_type), type_name(rn->tn_type), arg); 3175 break; 3176 case RETURN: 3177 /* combination of '%s' and '%s' in return */ 3178 warning(279, type_name(ln->tn_type), type_name(rn->tn_type)); 3179 break; 3180 default: 3181 /* combination of '%s' and '%s', op '%s' */ 3182 warning(242, type_name(ln->tn_type), type_name(rn->tn_type), 3183 op_name(op)); 3184 break; 3185 } 3186 } 3187 3188 static void 3189 typeok_enum(op_t op, const mod_t *mp, int arg, 3190 const tnode_t *ln, const type_t *ltp, 3191 const tnode_t *rn, const type_t *rtp) 3192 { 3193 if (mp->m_bad_on_enum && 3194 (ltp->t_is_enum || (mp->m_binary && rtp->t_is_enum))) { 3195 check_bad_enum_operation(op, ln, rn); 3196 } else if (mp->m_valid_on_enum && 3197 (ltp->t_is_enum && rtp != NULL && rtp->t_is_enum)) { 3198 check_enum_type_mismatch(op, arg, ln, rn); 3199 } else if (mp->m_valid_on_enum && 3200 (ltp->t_is_enum || (rtp != NULL && rtp->t_is_enum))) { 3201 check_enum_int_mismatch(op, arg, ln, rn); 3202 } 3203 } 3204 3205 /* Perform most type checks. Return whether the types are ok. */ 3206 bool 3207 typeok(op_t op, int arg, const tnode_t *ln, const tnode_t *rn) 3208 { 3209 3210 const mod_t *mp = &modtab[op]; 3211 3212 type_t *ltp = ln->tn_type; 3213 tspec_t lt = ltp->t_tspec; 3214 3215 type_t *rtp = mp->m_binary ? rn->tn_type : NULL; 3216 tspec_t rt = mp->m_binary ? rtp->t_tspec : NO_TSPEC; 3217 3218 if (Tflag && !typeok_scalar_strict_bool(op, mp, arg, ln, rn)) 3219 return false; 3220 if (!typeok_scalar(op, mp, ltp, lt, rtp, rt)) 3221 return false; 3222 3223 if (!typeok_op(op, arg, ln, ltp, lt, rn, rtp, rt)) 3224 return false; 3225 3226 typeok_enum(op, mp, arg, ln, ltp, rn, rtp); 3227 return true; 3228 } 3229 3230 /* In traditional C, keep unsigned and promote FLOAT to DOUBLE. */ 3231 static tspec_t 3232 promote_trad(tspec_t t) 3233 { 3234 3235 if (t == UCHAR || t == USHORT) 3236 return UINT; 3237 if (t == CHAR || t == SCHAR || t == SHORT) 3238 return INT; 3239 if (t == FLOAT) 3240 return DOUBLE; 3241 if (t == ENUM) 3242 return INT; 3243 return t; 3244 } 3245 3246 /* 3247 * C99 6.3.1.1p2 requires for types with lower rank than int that "If an int 3248 * can represent all the values of the original type, the value is converted 3249 * to an int; otherwise it is converted to an unsigned int", and that "All 3250 * other types are unchanged by the integer promotions". 3251 */ 3252 static tspec_t 3253 promote_c90(const tnode_t *tn, tspec_t t, bool farg) 3254 { 3255 if (tn->tn_type->t_bitfield) { 3256 unsigned int width = tn->tn_type->t_bit_field_width; 3257 unsigned int int_width = size_in_bits(INT); 3258 // XXX: What about _Bool bit-fields, since C99? 3259 if (width < int_width) 3260 return INT; 3261 if (width == int_width) 3262 return is_uinteger(t) ? UINT : INT; 3263 return t; 3264 } 3265 3266 if (t == CHAR || t == SCHAR) 3267 return INT; 3268 if (t == UCHAR) 3269 return size_in_bits(CHAR) < size_in_bits(INT) ? INT : UINT; 3270 if (t == SHORT) 3271 return INT; 3272 if (t == USHORT) 3273 return size_in_bits(SHORT) < size_in_bits(INT) ? INT : UINT; 3274 if (t == ENUM) 3275 return INT; 3276 if (farg && t == FLOAT) 3277 return DOUBLE; 3278 return t; 3279 } 3280 3281 /* 3282 * Performs the "integer promotions" (C99 6.3.1.1p2), which convert small 3283 * integer types to either int or unsigned int. 3284 * 3285 * If allow_c90 is unset or the operand is a function argument with no type 3286 * information (no prototype or variable # of args), converts float to double. 3287 */ 3288 tnode_t * 3289 promote(op_t op, bool farg, tnode_t *tn) 3290 { 3291 3292 tspec_t ot = tn->tn_type->t_tspec; 3293 if (!is_arithmetic(ot)) 3294 return tn; 3295 3296 tspec_t nt = allow_c90 ? promote_c90(tn, ot, farg) : promote_trad(ot); 3297 if (nt == ot) 3298 return tn; 3299 3300 type_t *ntp = expr_dup_type(tn->tn_type); 3301 ntp->t_tspec = nt; 3302 /* 3303 * Keep t_is_enum even though t_tspec gets converted from ENUM to INT, 3304 * so we are later able to check compatibility of enum types. 3305 */ 3306 return convert(op, 0, ntp, tn); 3307 } 3308 3309 static void 3310 convert_integer_from_floating(op_t op, const type_t *tp, const tnode_t *tn) 3311 { 3312 3313 if (op == CVT) 3314 /* cast from floating point '%s' to integer '%s' */ 3315 query_message(2, type_name(tn->tn_type), type_name(tp)); 3316 else 3317 /* implicit conversion from floating point '%s' to ... */ 3318 query_message(1, type_name(tn->tn_type), type_name(tp)); 3319 } 3320 3321 static bool 3322 should_warn_about_prototype_conversion(tspec_t nt, 3323 tspec_t ot, const tnode_t *ptn) 3324 { 3325 3326 if (nt == ot) 3327 return false; 3328 3329 if (nt == ENUM && ot == INT) 3330 return false; 3331 3332 if (is_floating(nt) != is_floating(ot) || 3333 portable_rank_cmp(nt, ot) != 0) { 3334 /* representation and/or width change */ 3335 if (!is_integer(ot)) 3336 return true; 3337 /* 3338 * XXX: Investigate whether this rule makes sense; see 3339 * tests/usr.bin/xlint/lint1/platform_long.c. 3340 */ 3341 return portable_rank_cmp(ot, INT) > 0; 3342 } 3343 3344 if (!hflag) 3345 return false; 3346 3347 /* 3348 * If the types differ only in sign and the argument has the same 3349 * representation in both types, print no warning. 3350 */ 3351 if (ptn->tn_op == CON && is_integer(nt) && 3352 signed_type(nt) == signed_type(ot) && 3353 !msb(ptn->tn_val.u.integer, ot)) 3354 return false; 3355 3356 return true; 3357 } 3358 3359 /* 3360 * Warn if a prototype causes a type conversion that is different from what 3361 * would happen to the same argument in the absence of a prototype. This 3362 * check is intended for code that needs to stay compatible with pre-C90 C. 3363 * 3364 * Errors/warnings about illegal type combinations are already printed 3365 * in check_assign_types_compatible(). 3366 */ 3367 static void 3368 check_prototype_conversion(int arg, tspec_t nt, tspec_t ot, type_t *tp, 3369 tnode_t *tn) 3370 { 3371 3372 if (!is_arithmetic(nt) || !is_arithmetic(ot)) 3373 return; 3374 3375 /* 3376 * If the type of the formal parameter is char/short, a warning would 3377 * be useless, because functions declared the old style can't expect 3378 * char/short arguments. 3379 */ 3380 if (nt == CHAR || nt == SCHAR || nt == UCHAR || 3381 nt == SHORT || nt == USHORT) 3382 return; 3383 3384 /* apply the default promotion */ 3385 tnode_t *ptn = promote(NOOP, true, tn); 3386 ot = ptn->tn_type->t_tspec; 3387 3388 if (should_warn_about_prototype_conversion(nt, ot, ptn)) { 3389 /* argument %d is converted from '%s' to '%s' ... */ 3390 warning(259, arg, type_name(tn->tn_type), type_name(tp)); 3391 } 3392 } 3393 3394 /* 3395 * When converting a large integer type to a small integer type, in some 3396 * cases the value of the actual expression is further restricted than the 3397 * type bounds, such as in (expr & 0xFF) or (expr % 100) or (expr >> 24). 3398 */ 3399 static bool 3400 can_represent(const type_t *tp, const tnode_t *tn) 3401 { 3402 3403 debug_step("%s: type '%s'", __func__, type_name(tp)); 3404 debug_node(tn); 3405 3406 uint64_t nmask = value_bits(width_in_bits(tp)); 3407 if (!is_uinteger(tp->t_tspec)) 3408 nmask >>= 1; 3409 3410 integer_constraints c = ic_expr(tn); 3411 if ((~c.bclr & ~nmask) == 0) 3412 return true; 3413 3414 integer_constraints tpc = ic_any(tp); 3415 if (is_uinteger(tp->t_tspec) 3416 ? tpc.umin <= c.umin && tpc.umax >= c.umax 3417 : tpc.smin <= c.smin && tpc.smax >= c.smax) 3418 return true; 3419 3420 return false; 3421 } 3422 3423 static bool 3424 should_warn_about_integer_conversion(const type_t *ntp, tspec_t nt, 3425 const tnode_t *otn, tspec_t ot) 3426 { 3427 3428 // XXX: The portable_rank_cmp aims at portable mode, independent of the 3429 // current platform, while can_represent acts on the actual type sizes 3430 // from the current platform. This mix is inconsistent, but anything 3431 // else would make the exact conditions too complicated to grasp. 3432 if (aflag > 0 && portable_rank_cmp(nt, ot) < 0) { 3433 if (ot == LONG || ot == ULONG 3434 || ot == LLONG || ot == ULLONG 3435 #ifdef INT128_SIZE 3436 || ot == INT128 || ot == UINT128 3437 #endif 3438 || aflag > 1) 3439 return !can_represent(ntp, otn); 3440 } 3441 return false; 3442 } 3443 3444 static void 3445 convert_integer_from_integer(op_t op, int arg, tspec_t nt, tspec_t ot, 3446 type_t *tp, tnode_t *tn) 3447 { 3448 3449 if (tn->tn_op == CON) 3450 return; 3451 3452 if (op == CVT) 3453 return; 3454 3455 if (Pflag && pflag && aflag > 0 && 3456 portable_rank_cmp(nt, ot) > 0 && 3457 is_uinteger(nt) != is_uinteger(ot)) { 3458 if (op == FARG) { 3459 /* conversion to '%s' may sign-extend ... */ 3460 warning(297, type_name(tp), arg); 3461 } else { 3462 /* conversion to '%s' may sign-extend ... */ 3463 warning(131, type_name(tp)); 3464 } 3465 } 3466 3467 if (Pflag && portable_rank_cmp(nt, ot) > 0 && 3468 (tn->tn_op == PLUS || tn->tn_op == MINUS || tn->tn_op == MULT || 3469 tn->tn_op == SHL)) { 3470 /* suggest cast from '%s' to '%s' on op '%s' to ... */ 3471 warning(324, type_name(gettyp(ot)), type_name(tp), 3472 op_name(tn->tn_op)); 3473 } 3474 3475 if (should_warn_about_integer_conversion(tp, nt, tn, ot)) { 3476 if (op == FARG) { 3477 /* conversion from '%s' to '%s' may lose ... */ 3478 warning(298, 3479 type_name(tn->tn_type), type_name(tp), arg); 3480 } else { 3481 /* conversion from '%s' to '%s' may lose accuracy */ 3482 warning(132, 3483 type_name(tn->tn_type), type_name(tp)); 3484 } 3485 } 3486 3487 if (any_query_enabled && is_uinteger(nt) != is_uinteger(ot)) 3488 /* implicit conversion changes sign from '%s' to '%s' */ 3489 query_message(3, type_name(tn->tn_type), type_name(tp)); 3490 } 3491 3492 static void 3493 convert_integer_from_pointer(op_t op, tspec_t nt, type_t *tp, tnode_t *tn) 3494 { 3495 3496 if (tn->tn_op == CON) 3497 return; 3498 if (op != CVT) 3499 return; /* We already got an error. */ 3500 if (portable_rank_cmp(nt, PTR) >= 0) 3501 return; 3502 3503 if (pflag && size_in_bits(nt) >= size_in_bits(PTR)) { 3504 /* conversion of pointer to '%s' may lose bits */ 3505 warning(134, type_name(tp)); 3506 } else { 3507 /* conversion of pointer to '%s' loses bits */ 3508 warning(133, type_name(tp)); 3509 } 3510 } 3511 3512 static bool 3513 struct_starts_with(const type_t *struct_tp, const type_t *member_tp) 3514 { 3515 3516 return struct_tp->t_sou->sou_first_member != NULL && 3517 types_compatible(struct_tp->t_sou->sou_first_member->s_type, 3518 member_tp, true, false, NULL); 3519 } 3520 3521 static bool 3522 is_byte_array(const type_t *tp) 3523 { 3524 3525 return tp->t_tspec == ARRAY && 3526 (tp->t_subt->t_tspec == CHAR || tp->t_subt->t_tspec == UCHAR); 3527 } 3528 3529 static bool 3530 union_contains(const type_t *utp, const type_t *mtp) 3531 { 3532 for (const sym_t *mem = utp->t_sou->sou_first_member; 3533 mem != NULL; mem = mem->s_next) { 3534 if (types_compatible(mem->s_type, mtp, true, false, NULL)) 3535 return true; 3536 } 3537 return false; 3538 } 3539 3540 static bool 3541 should_warn_about_pointer_cast(const type_t *nstp, tspec_t nst, 3542 const type_t *ostp, tspec_t ost) 3543 { 3544 3545 while (nst == ARRAY) 3546 nstp = nstp->t_subt, nst = nstp->t_tspec; 3547 while (ost == ARRAY) 3548 ostp = ostp->t_subt, ost = ostp->t_tspec; 3549 3550 if (nst == STRUCT && ost == STRUCT && 3551 (struct_starts_with(nstp, ostp) || 3552 struct_starts_with(ostp, nstp))) 3553 return false; 3554 3555 if (is_incomplete(nstp) || is_incomplete(ostp)) 3556 return false; 3557 3558 if (nst == CHAR || nst == UCHAR) 3559 return false; /* for the sake of traditional C code */ 3560 if (ost == CHAR || ost == UCHAR) 3561 return false; /* for the sake of traditional C code */ 3562 3563 /* Allow cast between pointers to sockaddr variants. */ 3564 if (nst == STRUCT && ost == STRUCT) { 3565 const sym_t *nmem = nstp->t_sou->sou_first_member; 3566 const sym_t *omem = ostp->t_sou->sou_first_member; 3567 while (nmem != NULL && omem != NULL && 3568 types_compatible(nmem->s_type, omem->s_type, 3569 true, false, NULL)) 3570 nmem = nmem->s_next, omem = omem->s_next; 3571 if (nmem != NULL && is_byte_array(nmem->s_type)) 3572 return false; 3573 if (omem != NULL && is_byte_array(omem->s_type)) 3574 return false; 3575 if (nmem == NULL && omem == NULL) 3576 return false; 3577 } 3578 3579 if (nst == UNION || ost == UNION) { 3580 const type_t *union_tp = nst == UNION ? nstp : ostp; 3581 const type_t *other_tp = nst == UNION ? ostp : nstp; 3582 if (union_contains(union_tp, other_tp)) 3583 return false; 3584 } 3585 3586 if (is_struct_or_union(nst) && is_struct_or_union(ost)) 3587 return nstp->t_sou != ostp->t_sou; 3588 3589 enum rank_kind rk1 = type_properties(nst)->tt_rank_kind; 3590 enum rank_kind rk2 = type_properties(ost)->tt_rank_kind; 3591 if (rk1 != rk2 || rk1 == RK_NONE) 3592 return true; 3593 3594 return portable_rank_cmp(nst, ost) != 0; 3595 } 3596 3597 static void 3598 convert_pointer_from_pointer(type_t *ntp, tnode_t *tn) 3599 { 3600 const type_t *nstp = ntp->t_subt; 3601 const type_t *otp = tn->tn_type; 3602 const type_t *ostp = otp->t_subt; 3603 tspec_t nst = nstp->t_tspec; 3604 tspec_t ost = ostp->t_tspec; 3605 3606 if (nst == VOID || ost == VOID) { 3607 /* TODO: C99 behaves like C90 here. */ 3608 if ((!allow_trad && !allow_c99) && (nst == FUNC || ost == FUNC)) { 3609 const char *nts, *ots; 3610 /* null pointers are already handled in convert() */ 3611 *(nst == FUNC ? &nts : &ots) = "function pointer"; 3612 *(nst == VOID ? &nts : &ots) = "'void *'"; 3613 /* conversion of %s to %s requires a cast */ 3614 warning(303, ots, nts); 3615 } 3616 return; 3617 } 3618 if (nst == FUNC && ost == FUNC) 3619 return; 3620 if (nst == FUNC || ost == FUNC) { 3621 /* converting '%s' to '%s' is questionable */ 3622 warning(229, type_name(otp), type_name(ntp)); 3623 return; 3624 } 3625 3626 if (hflag && alignment_in_bits(nstp) > alignment_in_bits(ostp) && 3627 ost != CHAR && ost != UCHAR && 3628 !is_incomplete(ostp) && 3629 !(nst == UNION && union_contains(nstp, ostp))) { 3630 /* converting '%s' to '%s' increases alignment ... */ 3631 warning(135, type_name(otp), type_name(ntp), 3632 alignment_in_bits(ostp) / CHAR_SIZE, 3633 alignment_in_bits(nstp) / CHAR_SIZE); 3634 } 3635 3636 if (cflag && should_warn_about_pointer_cast(nstp, nst, ostp, ost)) { 3637 /* pointer cast from '%s' to '%s' may be troublesome */ 3638 warning(247, type_name(otp), type_name(ntp)); 3639 } 3640 } 3641 3642 /* 3643 * Insert a conversion operator, which converts the type of the node 3644 * to another given type. 3645 * 3646 * Possible values for 'op': 3647 * CVT a cast-expression 3648 * binary integer promotion for one of the operands, or a usual 3649 * arithmetic conversion 3650 * binary plain or compound assignments to bit-fields 3651 * FARG 'arg' is the number of the parameter (used for warnings) 3652 * NOOP several other implicit conversions 3653 * ... 3654 */ 3655 tnode_t * 3656 convert(op_t op, int arg, type_t *tp, tnode_t *tn) 3657 { 3658 tspec_t nt = tp->t_tspec; 3659 tspec_t ot = tn->tn_type->t_tspec; 3660 3661 if (allow_trad && allow_c90 && op == FARG) 3662 check_prototype_conversion(arg, nt, ot, tp, tn); 3663 3664 if (nt == BOOL) { 3665 /* No further checks. */ 3666 3667 } else if (is_integer(nt)) { 3668 if (ot == BOOL) { 3669 /* No further checks. */ 3670 } else if (is_integer(ot)) 3671 convert_integer_from_integer(op, arg, nt, ot, tp, tn); 3672 else if (is_floating(ot)) 3673 convert_integer_from_floating(op, tp, tn); 3674 else if (ot == PTR) 3675 convert_integer_from_pointer(op, nt, tp, tn); 3676 3677 } else if (is_floating(nt)) { 3678 /* No further checks. */ 3679 3680 } else if (nt == PTR) { 3681 if (is_null_pointer(tn)) { 3682 /* a null pointer may be assigned to any pointer. */ 3683 } else if (ot == PTR && op == CVT) 3684 convert_pointer_from_pointer(tp, tn); 3685 } 3686 3687 tnode_t *ntn = expr_alloc_tnode(); 3688 ntn->tn_op = CVT; 3689 ntn->tn_type = tp; 3690 ntn->tn_cast = op == CVT; 3691 ntn->tn_sys |= tn->tn_sys; 3692 ntn->tn_right = NULL; 3693 if (tn->tn_op != CON || nt == VOID) { 3694 ntn->tn_left = tn; 3695 } else { 3696 ntn->tn_op = CON; 3697 convert_constant(op, arg, ntn->tn_type, &ntn->tn_val, 3698 &tn->tn_val); 3699 } 3700 3701 return ntn; 3702 } 3703 3704 static void 3705 convert_constant_floating(op_t op, int arg, tspec_t ot, const type_t *tp, 3706 tspec_t nt, val_t *v, val_t *nv) 3707 { 3708 long double max = 0.0, min = 0.0; 3709 3710 switch (nt) { 3711 case CHAR: 3712 max = TARG_CHAR_MAX; min = TARG_CHAR_MIN; break; 3713 case UCHAR: 3714 max = TARG_UCHAR_MAX; min = 0; break; 3715 case SCHAR: 3716 max = TARG_SCHAR_MAX; min = TARG_SCHAR_MIN; break; 3717 case SHORT: 3718 max = TARG_SHRT_MAX; min = TARG_SHRT_MIN; break; 3719 case USHORT: 3720 max = TARG_USHRT_MAX; min = 0; break; 3721 case ENUM: 3722 case INT: 3723 max = TARG_INT_MAX; min = TARG_INT_MIN; break; 3724 case UINT: 3725 max = TARG_UINT_MAX; min = 0; break; 3726 case LONG: 3727 max = TARG_LONG_MAX; min = TARG_LONG_MIN; break; 3728 case ULONG: 3729 max = TARG_ULONG_MAX; min = 0; break; 3730 case LLONG: 3731 max = LLONG_MAX; min = LLONG_MIN; break; 3732 case ULLONG: 3733 max = ULLONG_MAX; min = 0; break; 3734 case FLOAT: 3735 case FCOMPLEX: 3736 max = FLT_MAX; min = -FLT_MAX; break; 3737 case DOUBLE: 3738 case DCOMPLEX: 3739 max = DBL_MAX; min = -DBL_MAX; break; 3740 case PTR: 3741 /* Already got an error because of float --> ptr */ 3742 case LDOUBLE: 3743 case LCOMPLEX: 3744 /* LINTED 248 */ 3745 max = LDBL_MAX; min = -max; break; 3746 default: 3747 lint_assert(/*CONSTCOND*/false); 3748 } 3749 if (v->u.floating > max || v->u.floating < min) { 3750 lint_assert(nt != LDOUBLE); 3751 if (op == FARG) { 3752 /* conversion of '%s' to '%s' is out of range, ... */ 3753 warning(295, 3754 type_name(gettyp(ot)), type_name(tp), arg); 3755 } else { 3756 /* conversion of '%s' to '%s' is out of range */ 3757 warning(119, type_name(gettyp(ot)), type_name(tp)); 3758 } 3759 v->u.floating = v->u.floating > 0 ? max : min; 3760 } 3761 3762 if (nt == FLOAT || nt == FCOMPLEX) 3763 nv->u.floating = (float)v->u.floating; 3764 else if (nt == DOUBLE || nt == DCOMPLEX) 3765 nv->u.floating = (double)v->u.floating; 3766 else if (nt == LDOUBLE || nt == LCOMPLEX) 3767 nv->u.floating = v->u.floating; 3768 else 3769 nv->u.integer = (int64_t)v->u.floating; 3770 } 3771 3772 static bool 3773 convert_constant_to_floating(tspec_t nt, val_t *nv, 3774 tspec_t ot, const val_t *v) 3775 { 3776 if (nt == FLOAT) { 3777 nv->u.floating = (ot == PTR || is_uinteger(ot)) ? 3778 (float)(uint64_t)v->u.integer : (float)v->u.integer; 3779 } else if (nt == DOUBLE) { 3780 nv->u.floating = (ot == PTR || is_uinteger(ot)) ? 3781 (double)(uint64_t)v->u.integer : (double)v->u.integer; 3782 } else if (nt == LDOUBLE) { 3783 nv->u.floating = (ot == PTR || is_uinteger(ot)) 3784 ? (long double)(uint64_t)v->u.integer 3785 : (long double)v->u.integer; 3786 } else 3787 return false; 3788 return true; 3789 } 3790 3791 /* 3792 * Print a warning if bits which were set are lost due to the conversion. 3793 * This can happen with operator ORASS only. 3794 */ 3795 static void 3796 convert_constant_check_range_bitor(size_t nsz, size_t osz, const val_t *v, 3797 uint64_t xmask, op_t op) 3798 { 3799 if (nsz < osz && (v->u.integer & xmask) != 0) { 3800 /* constant truncated by conversion, op '%s' */ 3801 warning(306, op_name(op)); 3802 } 3803 } 3804 3805 /* 3806 * Print a warning if additional bits are not all 1 3807 * and the most significant bit of the old value is 1, 3808 * or if at least one (but not all) removed bit was 0. 3809 */ 3810 static void 3811 convert_constant_check_range_bitand(size_t nsz, size_t osz, 3812 uint64_t xmask, const val_t *nv, 3813 tspec_t ot, const val_t *v, 3814 const type_t *tp, op_t op) 3815 { 3816 if (nsz > osz && 3817 (nv->u.integer & bit((unsigned int)(osz - 1))) != 0 && 3818 (nv->u.integer & xmask) != xmask) { 3819 /* extra bits set to 0 in conversion of '%s' to '%s', ... */ 3820 warning(309, type_name(gettyp(ot)), 3821 type_name(tp), op_name(op)); 3822 } else if (nsz < osz && 3823 (v->u.integer & xmask) != xmask && 3824 (v->u.integer & xmask) != 0) { 3825 /* constant truncated by conversion, op '%s' */ 3826 warning(306, op_name(op)); 3827 } 3828 } 3829 3830 static void 3831 convert_constant_check_range_signed(op_t op, int arg) 3832 { 3833 if (op == ASSIGN) { 3834 /* assignment of negative constant to unsigned type */ 3835 warning(164); 3836 } else if (op == INIT) { 3837 /* initialization of unsigned with negative constant */ 3838 warning(221); 3839 } else if (op == FARG) { 3840 /* conversion of negative constant to unsigned type, ... */ 3841 warning(296, arg); 3842 } else if (modtab[op].m_comparison) { 3843 /* handled by check_integer_comparison() */ 3844 } else { 3845 /* conversion of negative constant to unsigned type */ 3846 warning(222); 3847 } 3848 } 3849 3850 /* 3851 * Loss of significant bit(s). All truncated bits of unsigned types or all 3852 * truncated bits plus the msb of the target for signed types are considered 3853 * to be significant bits. Loss of significant bits means that at least one 3854 * of the bits was set in an unsigned type or that at least one but not all 3855 * of the bits was set in a signed type. Loss of significant bits means that 3856 * it is not possible, also not with necessary casts, to convert back to the 3857 * original type. An example for a necessary cast is: 3858 * char c; int i; c = 128; 3859 * i = c; ** yields -128 ** 3860 * i = (unsigned char)c; ** yields 128 ** 3861 */ 3862 static void 3863 warn_constant_check_range_truncated(op_t op, int arg, const type_t *tp, 3864 tspec_t ot) 3865 { 3866 if (op == ASSIGN && tp->t_bitfield) 3867 /* precision lost in bit-field assignment */ 3868 warning(166); 3869 else if (op == ASSIGN) 3870 /* constant truncated by assignment */ 3871 warning(165); 3872 else if (op == INIT && tp->t_bitfield) 3873 /* bit-field initializer does not fit */ 3874 warning(180); 3875 else if (op == INIT) 3876 /* initializer does not fit */ 3877 warning(178); 3878 else if (op == CASE) 3879 /* case label affected by conversion */ 3880 warning(196); 3881 else if (op == FARG) 3882 /* conversion of '%s' to '%s' is out of range, arg #%d */ 3883 warning(295, type_name(gettyp(ot)), type_name(tp), arg); 3884 else 3885 /* conversion of '%s' to '%s' is out of range */ 3886 warning(119, type_name(gettyp(ot)), type_name(tp)); 3887 } 3888 3889 static void 3890 warn_constant_check_range_loss(op_t op, int arg, const type_t *tp, 3891 tspec_t ot) 3892 { 3893 if (op == ASSIGN && tp->t_bitfield) 3894 /* precision lost in bit-field assignment */ 3895 warning(166); 3896 else if (op == INIT && tp->t_bitfield) 3897 /* bit-field initializer out of range */ 3898 warning(11); 3899 else if (op == CASE) 3900 /* case label affected by conversion */ 3901 warning(196); 3902 else if (op == FARG) 3903 /* conversion of '%s' to '%s' is out of range, arg #%d */ 3904 warning(295, type_name(gettyp(ot)), type_name(tp), arg); 3905 else 3906 /* conversion of '%s' to '%s' is out of range */ 3907 warning(119, type_name(gettyp(ot)), type_name(tp)); 3908 } 3909 3910 static void 3911 convert_constant_check_range(tspec_t ot, const type_t *tp, tspec_t nt, 3912 op_t op, int arg, const val_t *v, val_t *nv) 3913 { 3914 unsigned int obitsz, nbitsz; 3915 uint64_t xmask, xmsk1; 3916 3917 obitsz = size_in_bits(ot); 3918 nbitsz = tp->t_bitfield ? tp->t_bit_field_width : size_in_bits(nt); 3919 xmask = value_bits(nbitsz) ^ value_bits(obitsz); 3920 xmsk1 = value_bits(nbitsz) ^ value_bits(obitsz - 1); 3921 /* 3922 * For bitwise operations we are not interested in the arithmetic 3923 * value, but in the bits itself. 3924 */ 3925 if (op == ORASS || op == BITOR || op == BITXOR) { 3926 convert_constant_check_range_bitor( 3927 nbitsz, obitsz, v, xmask, op); 3928 } else if (op == ANDASS || op == BITAND) { 3929 convert_constant_check_range_bitand( 3930 nbitsz, obitsz, xmask, nv, ot, v, tp, op); 3931 } else if ((nt != PTR && is_uinteger(nt)) && 3932 (ot != PTR && !is_uinteger(ot)) && 3933 v->u.integer < 0) 3934 convert_constant_check_range_signed(op, arg); 3935 else if (nv->u.integer != v->u.integer && nbitsz <= obitsz && 3936 (v->u.integer & xmask) != 0 && 3937 (is_uinteger(ot) || (v->u.integer & xmsk1) != xmsk1)) 3938 warn_constant_check_range_truncated(op, arg, tp, ot); 3939 else if (nv->u.integer != v->u.integer) 3940 warn_constant_check_range_loss(op, arg, tp, ot); 3941 } 3942 3943 /*- 3944 * Converts a typed constant to a constant of another type. 3945 * 3946 * op operator which requires conversion 3947 * arg if op is FARG, # of parameter 3948 * tp type to which to convert the constant 3949 * nv new constant 3950 * v old constant 3951 */ 3952 void 3953 convert_constant(op_t op, int arg, const type_t *tp, val_t *nv, val_t *v) 3954 { 3955 /* 3956 * TODO: make 'v' const; the name of this function does not suggest 3957 * that it modifies 'v'. 3958 */ 3959 tspec_t ot = v->v_tspec; 3960 tspec_t nt = nv->v_tspec = tp->t_tspec; 3961 bool range_check = false; 3962 3963 if (nt == BOOL) { /* C99 6.3.1.2 */ 3964 nv->v_unsigned_since_c90 = false; 3965 nv->u.integer = is_nonzero_val(v) ? 1 : 0; 3966 return; 3967 } 3968 3969 if (ot == FLOAT || ot == DOUBLE || ot == LDOUBLE) 3970 convert_constant_floating(op, arg, ot, tp, nt, v, nv); 3971 else if (!convert_constant_to_floating(nt, nv, ot, v)) { 3972 range_check = true; /* Check for lost precision. */ 3973 nv->u.integer = v->u.integer; 3974 } 3975 3976 if (allow_trad && allow_c90 && v->v_unsigned_since_c90 && 3977 (is_floating(nt) || ( 3978 (is_integer(nt) && !is_uinteger(nt) && 3979 portable_rank_cmp(nt, ot) > 0)))) { 3980 /* C90 treats constant as unsigned */ 3981 warning(157); 3982 v->v_unsigned_since_c90 = false; 3983 } 3984 3985 if (is_integer(nt)) { 3986 nv->u.integer = convert_integer(nv->u.integer, nt, 3987 tp->t_bitfield ? tp->t_bit_field_width : size_in_bits(nt)); 3988 } 3989 3990 if (range_check && op != CVT) 3991 convert_constant_check_range(ot, tp, nt, op, arg, v, nv); 3992 } 3993 3994 /* 3995 * Create a constant node for sizeof. 3996 */ 3997 tnode_t * 3998 build_sizeof(const type_t *tp) 3999 { 4000 unsigned int size_in_bytes = type_size_in_bits(tp) / CHAR_SIZE; 4001 tnode_t *tn = build_integer_constant(SIZEOF_TSPEC, size_in_bytes); 4002 tn->tn_system_dependent = true; 4003 debug_step("build_sizeof '%s' = %u", type_name(tp), size_in_bytes); 4004 return tn; 4005 } 4006 4007 /* 4008 * Create a constant node for offsetof. 4009 */ 4010 tnode_t * 4011 build_offsetof(const type_t *tp, const sym_t *sym) 4012 { 4013 unsigned int offset_in_bits = 0; 4014 4015 if (!is_struct_or_union(tp->t_tspec)) { 4016 /* unacceptable operand of '%s' */ 4017 error(111, "offsetof"); 4018 goto proceed; 4019 } 4020 sym_t *mem = find_member(tp->t_sou, sym->s_name); 4021 if (mem == NULL) { 4022 /* type '%s' does not have member '%s' */ 4023 error(101, sym->s_name, type_name(tp)); 4024 goto proceed; 4025 } 4026 offset_in_bits = mem->u.s_member.sm_offset_in_bits; 4027 4028 proceed:; 4029 unsigned int offset_in_bytes = offset_in_bits / CHAR_SIZE; 4030 tnode_t *tn = build_integer_constant(SIZEOF_TSPEC, offset_in_bytes); 4031 tn->tn_system_dependent = true; 4032 return tn; 4033 } 4034 4035 unsigned int 4036 type_size_in_bits(const type_t *tp) 4037 { 4038 4039 unsigned int elem = 1; 4040 bool flex = false; 4041 lint_assert(tp != NULL); 4042 while (tp->t_tspec == ARRAY) { 4043 flex = true; /* allow c99 flex arrays [] [0] */ 4044 elem *= tp->t_dim; 4045 tp = tp->t_subt; 4046 } 4047 if (elem == 0 && !flex) { 4048 /* cannot take size/alignment of incomplete type */ 4049 error(143); 4050 elem = 1; 4051 } 4052 4053 unsigned int elsz; 4054 switch (tp->t_tspec) { 4055 case VOID: 4056 /* cannot take size/alignment of void */ 4057 error(146); 4058 elsz = 1; 4059 break; 4060 case FUNC: 4061 /* cannot take size/alignment of function type '%s' */ 4062 error(144, type_name(tp)); 4063 elsz = 1; 4064 break; 4065 case STRUCT: 4066 case UNION: 4067 if (is_incomplete(tp)) { 4068 /* cannot take size/alignment of incomplete type */ 4069 error(143); 4070 elsz = 1; 4071 } else { 4072 elsz = tp->t_sou->sou_size_in_bits; 4073 } 4074 break; 4075 case ENUM: 4076 if (is_incomplete(tp)) { 4077 /* cannot take size/alignment of incomplete type */ 4078 warning(143); 4079 } 4080 /* FALLTHROUGH */ 4081 default: 4082 if (tp->t_bitfield) { 4083 /* cannot take size/alignment of bit-field */ 4084 error(145); 4085 } 4086 elsz = size_in_bits(tp->t_tspec); 4087 lint_assert(elsz > 0); 4088 break; 4089 } 4090 4091 return elem * elsz; 4092 } 4093 4094 /* C11 6.5.3.4, GCC */ 4095 tnode_t * 4096 build_alignof(const type_t *tp) 4097 { 4098 if (tp->t_tspec == FUNC) { 4099 /* cannot take size/alignment of function type '%s' */ 4100 error(144, type_name(tp)); 4101 return NULL; 4102 } 4103 if (tp->t_tspec == VOID) { 4104 /* cannot take size/alignment of void */ 4105 error(146); 4106 return NULL; 4107 } 4108 if (is_incomplete(tp)) { 4109 /* cannot take size/alignment of incomplete type */ 4110 error(143); 4111 return NULL; 4112 } 4113 if (tp->t_bitfield) { 4114 /* cannot take size/alignment of bit-field */ 4115 error(145); 4116 return NULL; 4117 } 4118 return build_integer_constant(SIZEOF_TSPEC, 4119 (int64_t)alignment_in_bits(tp) / CHAR_SIZE); 4120 } 4121 4122 static tnode_t * 4123 cast_to_union(tnode_t *otn, type_t *ntp) 4124 { 4125 4126 if (!allow_gcc) { 4127 /* union cast is a GCC extension */ 4128 error(328); 4129 return NULL; 4130 } 4131 4132 for (const sym_t *m = ntp->t_sou->sou_first_member; 4133 m != NULL; m = m->s_next) { 4134 if (types_compatible(m->s_type, otn->tn_type, 4135 false, false, NULL)) { 4136 tnode_t *ntn = expr_alloc_tnode(); 4137 ntn->tn_op = CVT; 4138 ntn->tn_type = ntp; 4139 ntn->tn_cast = true; 4140 ntn->tn_left = otn; 4141 ntn->tn_right = NULL; 4142 return ntn; 4143 } 4144 } 4145 4146 /* type '%s' is not a member of '%s' */ 4147 error(329, type_name(otn->tn_type), type_name(ntp)); 4148 return NULL; 4149 } 4150 4151 /* 4152 * Type casts. 4153 */ 4154 tnode_t * 4155 cast(tnode_t *tn, type_t *tp) 4156 { 4157 4158 if (tn == NULL) 4159 return NULL; 4160 4161 tn = cconv(tn); 4162 4163 lint_assert(tp != NULL); 4164 tspec_t nt = tp->t_tspec; 4165 tspec_t ot = tn->tn_type->t_tspec; 4166 4167 if (nt == VOID) { 4168 /* 4169 * C90 6.3.4, C99 6.5.4p2 and C11 6.5.4p2 allow any type to be 4170 * cast to void. The only other allowed casts are from a 4171 * scalar type to a scalar type. 4172 */ 4173 } else if (nt == UNION) 4174 return cast_to_union(tn, tp); 4175 else if (nt == STRUCT || nt == ARRAY || nt == FUNC) { 4176 /* Casting to a struct is an undocumented GCC extension. */ 4177 if (!(allow_gcc && nt == STRUCT)) 4178 goto invalid_cast; 4179 } else if (is_struct_or_union(ot)) 4180 goto invalid_cast; 4181 else if (ot == VOID) { 4182 /* improper cast of void expression */ 4183 error(148); 4184 return NULL; 4185 } else if (is_integer(nt) && is_scalar(ot)) { 4186 /* ok */ 4187 } else if (is_floating(nt) && is_arithmetic(ot)) { 4188 /* ok */ 4189 } else if (nt == PTR && is_integer(ot)) { 4190 /* ok */ 4191 } else if (nt == PTR && ot == PTR) { 4192 if (!tp->t_subt->t_const && tn->tn_type->t_subt->t_const) { 4193 if (hflag) 4194 /* cast discards 'const' from type '%s' */ 4195 warning(275, type_name(tn->tn_type)); 4196 } 4197 } else 4198 goto invalid_cast; 4199 4200 if (any_query_enabled && types_compatible(tp, tn->tn_type, 4201 false, false, NULL)) { 4202 /* no-op cast from '%s' to '%s' */ 4203 query_message(6, type_name(tn->tn_type), type_name(tp)); 4204 } 4205 4206 tn = convert(CVT, 0, tp, tn); 4207 tn->tn_cast = true; 4208 4209 return tn; 4210 4211 invalid_cast: 4212 /* invalid cast from '%s' to '%s' */ 4213 error(147, type_name(tn->tn_type), type_name(tp)); 4214 return NULL; 4215 } 4216 4217 /* 4218 * Create the node for a function argument. 4219 * All necessary conversions and type checks are done in 4220 * build_function_call because build_function_argument has no 4221 * information about the expected parameter types. 4222 */ 4223 tnode_t * 4224 build_function_argument(tnode_t *args, tnode_t *arg) 4225 { 4226 /* 4227 * If there was a serious error in the expression for the argument, 4228 * create a dummy argument so the positions of the remaining arguments 4229 * will not change. 4230 */ 4231 if (arg == NULL) 4232 arg = build_integer_constant(INT, 0); 4233 4234 return build_op(PUSH, arg->tn_sys, arg->tn_type, arg, args); 4235 } 4236 4237 /* 4238 * Compare the type of an argument with the corresponding type of a 4239 * prototype parameter. If it is a valid combination, but both types 4240 * are not the same, insert a conversion to convert the argument into 4241 * the type of the parameter. 4242 */ 4243 static tnode_t * 4244 check_prototype_argument( 4245 int n, /* pos of arg */ 4246 type_t *tp, /* expected type (from prototype) */ 4247 tnode_t *tn) /* argument */ 4248 { 4249 tnode_t *ln = xcalloc(1, sizeof(*ln)); 4250 ln->tn_type = expr_unqualified_type(tp); 4251 ln->tn_lvalue = true; 4252 if (typeok(FARG, n, ln, tn)) { 4253 bool dowarn; 4254 if (!types_compatible(tp, tn->tn_type, 4255 true, false, (dowarn = false, &dowarn)) || dowarn) 4256 tn = convert(FARG, n, tp, tn); 4257 } 4258 free(ln); 4259 return tn; 4260 } 4261 4262 /* 4263 * Check types of all function arguments and insert conversions, 4264 * if necessary. 4265 */ 4266 static tnode_t * 4267 check_function_arguments(type_t *ftp, tnode_t *args) 4268 { 4269 /* get # of parameters in the prototype */ 4270 int npar = 0; 4271 for (const sym_t *p = ftp->t_params; p != NULL; p = p->s_next) 4272 npar++; 4273 4274 /* get # of arguments in the function call */ 4275 int narg = 0; 4276 for (const tnode_t *arg = args; arg != NULL; arg = tn_ck_right(arg)) 4277 narg++; 4278 4279 const sym_t *param = ftp->t_params; 4280 if (ftp->t_proto && npar != narg && !(ftp->t_vararg && npar < narg)) { 4281 /* argument mismatch: %d %s passed, %d expected */ 4282 error(150, narg, narg != 1 ? "arguments" : "argument", npar); 4283 param = NULL; 4284 } 4285 4286 for (int n = 1; n <= narg; n++) { 4287 4288 // The rightmost argument starts the argument list. 4289 tnode_t *arg = args; 4290 for (int i = narg; i > n; i--, arg = arg->tn_right) 4291 continue; 4292 4293 /* some things which are always not allowed */ 4294 tspec_t at = arg->tn_left->tn_type->t_tspec; 4295 if (at == VOID) { 4296 /* void expressions may not be arguments, arg #%d */ 4297 error(151, n); 4298 return NULL; 4299 } 4300 if (is_struct_or_union(at) && 4301 is_incomplete(arg->tn_left->tn_type)) { 4302 /* argument cannot have unknown size, arg #%d */ 4303 error(152, n); 4304 return NULL; 4305 } 4306 if (is_integer(at) && 4307 arg->tn_left->tn_type->t_is_enum && 4308 is_incomplete(arg->tn_left->tn_type)) { 4309 /* argument cannot have unknown size, arg #%d */ 4310 warning(152, n); 4311 } 4312 4313 /* class conversions (arg in value context) */ 4314 arg->tn_left = cconv(arg->tn_left); 4315 4316 if (param != NULL) { 4317 arg->tn_left = check_prototype_argument( 4318 n, param->s_type, arg->tn_left); 4319 } else 4320 arg->tn_left = promote(NOOP, true, arg->tn_left); 4321 arg->tn_type = arg->tn_left->tn_type; 4322 4323 if (param != NULL) 4324 param = param->s_next; 4325 } 4326 4327 return args; 4328 } 4329 4330 /* 4331 * Create the node for a function call. Also check types of 4332 * function arguments and insert conversions, if necessary. 4333 */ 4334 tnode_t * 4335 build_function_call(tnode_t *func, bool sys, tnode_t *args) 4336 { 4337 4338 if (func == NULL) 4339 return NULL; 4340 4341 op_t fcop = func->tn_op == NAME && func->tn_type->t_tspec == FUNC 4342 ? CALL : ICALL; 4343 4344 check_ctype_function_call(func, args); 4345 4346 /* Turn the function name into a pointer to the function. */ 4347 func = cconv(func); 4348 4349 if (func->tn_type->t_tspec != PTR || 4350 func->tn_type->t_subt->t_tspec != FUNC) { 4351 /* cannot call '%s', must be a function */ 4352 error(149, type_name(func->tn_type)); 4353 return NULL; 4354 } 4355 4356 args = check_function_arguments(func->tn_type->t_subt, args); 4357 4358 return build_op(fcop, sys, func->tn_type->t_subt->t_subt, func, args); 4359 } 4360 4361 /* 4362 * Return the value of an integral constant expression. 4363 * If the expression is not constant or its type is not an integer 4364 * type, an error message is printed. 4365 */ 4366 val_t * 4367 integer_constant(tnode_t *tn, bool required) 4368 { 4369 4370 if (tn != NULL) 4371 tn = cconv(tn); 4372 if (tn != NULL) 4373 tn = promote(NOOP, false, tn); 4374 4375 val_t *v = xcalloc(1, sizeof(*v)); 4376 4377 if (tn == NULL) { 4378 lint_assert(seen_error); 4379 debug_step("constant node is null; returning 1 instead"); 4380 v->v_tspec = INT; 4381 v->u.integer = 1; 4382 return v; 4383 } 4384 4385 v->v_tspec = tn->tn_type->t_tspec; 4386 4387 if (tn->tn_op == CON) { 4388 lint_assert(tn->tn_type->t_tspec == tn->tn_val.v_tspec); 4389 if (is_integer(tn->tn_val.v_tspec)) { 4390 v->v_unsigned_since_c90 = 4391 tn->tn_val.v_unsigned_since_c90; 4392 v->u.integer = tn->tn_val.u.integer; 4393 return v; 4394 } 4395 v->u.integer = (int64_t)tn->tn_val.u.floating; 4396 } else { 4397 v->u.integer = 1; 4398 } 4399 4400 if (required) 4401 /* integral constant expression expected */ 4402 error(55); 4403 else 4404 /* variable array dimension is a C99/GCC extension */ 4405 c99ism(318); 4406 4407 if (!is_integer(v->v_tspec)) 4408 v->v_tspec = INT; 4409 4410 return v; 4411 } 4412 4413 static bool 4414 is_constcond_false(const tnode_t *tn, tspec_t t) 4415 { 4416 return (t == BOOL || t == INT) && 4417 tn->tn_op == CON && tn->tn_val.u.integer == 0; 4418 } 4419 4420 /* 4421 * Perform some tests on expressions which can't be done in build_binary() 4422 * and functions called by build_binary(). These tests must be done here 4423 * because we need some information about the context in which the operations 4424 * are performed. 4425 * After all tests are performed and dofreeblk is true, expr() frees the 4426 * memory which is used for the expression. 4427 */ 4428 void 4429 expr(tnode_t *tn, bool vctx, bool cond, bool dofreeblk, bool is_do_while) 4430 { 4431 4432 if (tn == NULL) { /* in case of errors */ 4433 expr_free_all(); 4434 return; 4435 } 4436 4437 /* expr() is also called in global initializations */ 4438 if (dcs->d_kind != DLK_EXTERN && !is_do_while) 4439 check_statement_reachable(); 4440 4441 check_expr_misc(tn, vctx, cond, !cond, false, false, false); 4442 if (tn->tn_op == ASSIGN && !tn->tn_parenthesized) { 4443 if (hflag && cond) 4444 /* assignment in conditional context */ 4445 warning(159); 4446 } else if (tn->tn_op == CON) { 4447 if (hflag && cond && !suppress_constcond && 4448 !tn->tn_system_dependent && 4449 !(is_do_while && 4450 is_constcond_false(tn, tn->tn_type->t_tspec))) 4451 /* constant in conditional context */ 4452 warning(161); 4453 } 4454 if (!modtab[tn->tn_op].m_has_side_effect) { 4455 /* 4456 * for left operands of COMMA this warning is already printed 4457 */ 4458 if (tn->tn_op != COMMA && !vctx && !cond) 4459 check_null_effect(tn); 4460 } 4461 debug_node(tn); 4462 4463 /* free the tree memory */ 4464 if (dofreeblk) 4465 expr_free_all(); 4466 } 4467 4468 /* 4469 * Checks the range of array indices, if possible. 4470 * amper is set if only the address of the element is used. This 4471 * means that the index is allowed to refer to the first element 4472 * after the array. 4473 */ 4474 static void 4475 check_array_index(tnode_t *tn, bool amper) 4476 { 4477 lint_assert(has_operands(tn)); 4478 const tnode_t *ln = tn->tn_left; 4479 const tnode_t *rn = tn->tn_right; 4480 4481 /* We can only check constant indices. */ 4482 if (rn->tn_op != CON) 4483 return; 4484 4485 /* Return if the left node does not stem from an array. */ 4486 if (ln->tn_op != ADDR) 4487 return; 4488 if (ln->tn_left->tn_op != STRING && ln->tn_left->tn_op != NAME) 4489 return; 4490 if (ln->tn_left->tn_type->t_tspec != ARRAY) 4491 return; 4492 4493 /* 4494 * For incomplete array types, we can print a warning only if the index 4495 * is negative. 4496 */ 4497 if (is_incomplete(ln->tn_left->tn_type) && rn->tn_val.u.integer >= 0) 4498 return; 4499 4500 /* Get the size of one array element */ 4501 int elsz = length_in_bits(ln->tn_type->t_subt, NULL); 4502 if (elsz == 0) 4503 return; 4504 elsz /= CHAR_SIZE; 4505 4506 /* Change the unit of the index from bytes to element size. */ 4507 int64_t con = is_uinteger(rn->tn_type->t_tspec) 4508 ? (int64_t)((uint64_t)rn->tn_val.u.integer / elsz) 4509 : rn->tn_val.u.integer / elsz; 4510 4511 int dim = ln->tn_left->tn_type->t_dim + (amper ? 1 : 0); 4512 4513 if (!is_uinteger(rn->tn_type->t_tspec) && con < 0) { 4514 /* array subscript cannot be negative: %ld */ 4515 warning(167, (long)con); 4516 } else if (dim > 0 && (uint64_t)con >= (uint64_t)dim) { 4517 /* array subscript cannot be > %d: %ld */ 4518 warning(168, dim - 1, (long)con); 4519 } 4520 } 4521 4522 static void 4523 check_expr_addr(const tnode_t *ln, bool szof, bool fcall) 4524 { 4525 /* XXX: Taking warn_about_unreachable into account here feels wrong. */ 4526 if (ln->tn_op == NAME && (reached || !warn_about_unreachable)) { 4527 if (!szof) 4528 mark_as_set(ln->tn_sym); 4529 mark_as_used(ln->tn_sym, fcall, szof); 4530 } 4531 if (ln->tn_op == INDIR && ln->tn_left->tn_op == PLUS) 4532 /* check the range of array indices */ 4533 check_array_index(ln->tn_left, true); 4534 } 4535 4536 static void 4537 check_expr_load(const tnode_t *ln) 4538 { 4539 if (ln->tn_op == INDIR && ln->tn_left->tn_op == PLUS) 4540 /* check the range of array indices */ 4541 check_array_index(ln->tn_left, false); 4542 } 4543 4544 /* 4545 * If there is an asm statement in one of the compound statements around, 4546 * there may be other side effects, so don't warn. 4547 */ 4548 static bool 4549 is_asm_around(void) 4550 { 4551 for (decl_level *dl = dcs; dl != NULL; dl = dl->d_enclosing) 4552 if (dl->d_asm) 4553 return true; 4554 return false; 4555 } 4556 4557 static void 4558 check_expr_side_effect(const tnode_t *ln, bool szof) 4559 { 4560 4561 /* XXX: Taking warn_about_unreachable into account here feels wrong. */ 4562 if (ln->tn_op == NAME && (reached || !warn_about_unreachable)) { 4563 scl_t sc = ln->tn_sym->s_scl; 4564 if (sc != EXTERN && sc != STATIC && 4565 !ln->tn_sym->s_set && !szof && !is_asm_around()) { 4566 /* '%s' may be used before set */ 4567 warning(158, ln->tn_sym->s_name); 4568 mark_as_set(ln->tn_sym); 4569 } 4570 mark_as_used(ln->tn_sym, false, false); 4571 } 4572 } 4573 4574 static void 4575 check_expr_assign(const tnode_t *ln, bool szof) 4576 { 4577 /* XXX: Taking warn_about_unreachable into account here feels wrong. */ 4578 if (ln->tn_op == NAME && !szof && (reached || !warn_about_unreachable)) { 4579 mark_as_set(ln->tn_sym); 4580 if (ln->tn_sym->s_scl == EXTERN) 4581 outusg(ln->tn_sym); 4582 } 4583 if (ln->tn_op == INDIR && ln->tn_left->tn_op == PLUS) 4584 /* check the range of array indices */ 4585 check_array_index(ln->tn_left, false); 4586 } 4587 4588 static void 4589 check_expr_call(const tnode_t *tn, const tnode_t *ln, 4590 bool szof, bool vctx, bool cond, bool retval_discarded) 4591 { 4592 lint_assert(ln->tn_op == ADDR); 4593 lint_assert(ln->tn_left->tn_op == NAME); 4594 if (!szof && !is_compiler_builtin(ln->tn_left->tn_sym->s_name)) 4595 outcall(tn, vctx || cond, retval_discarded); 4596 } 4597 4598 static void 4599 check_expr_op(const tnode_t *tn, op_t op, const tnode_t *ln, 4600 bool szof, bool fcall, bool vctx, bool cond, 4601 bool retval_discarded, bool eqwarn) 4602 { 4603 switch (op) { 4604 case ADDR: 4605 check_expr_addr(ln, szof, fcall); 4606 break; 4607 case LOAD: 4608 check_expr_load(ln); 4609 /* FALLTHROUGH */ 4610 case PUSH: 4611 case INCBEF: 4612 case DECBEF: 4613 case INCAFT: 4614 case DECAFT: 4615 case ADDASS: 4616 case SUBASS: 4617 case MULASS: 4618 case DIVASS: 4619 case MODASS: 4620 case ANDASS: 4621 case ORASS: 4622 case XORASS: 4623 case SHLASS: 4624 case SHRASS: 4625 case REAL: 4626 case IMAG: 4627 check_expr_side_effect(ln, szof); 4628 break; 4629 case ASSIGN: 4630 check_expr_assign(ln, szof); 4631 break; 4632 case CALL: 4633 check_expr_call(tn, ln, szof, vctx, cond, retval_discarded); 4634 break; 4635 case EQ: 4636 if (hflag && eqwarn) 4637 /* operator '==' found where '=' was expected */ 4638 warning(160); 4639 break; 4640 default: 4641 break; 4642 } 4643 } 4644 4645 /* 4646 * vctx ??? 4647 * cond whether the expression is a condition that 4648 * will be compared with 0 4649 * eqwarn whether the operator '==' might be a 4650 * misspelled '=' 4651 * fcall whether the expression is a function call 4652 * retval_discarded whether the return value of a function call 4653 * is discarded; such calls will be analyzed by 4654 * lint2 in messages 4, 8 and 9 4655 * szof whether the expression is part of a sizeof 4656 * expression, which means that its value is 4657 * discarded since only the type is relevant 4658 */ 4659 void 4660 check_expr_misc(const tnode_t *tn, bool vctx, bool cond, 4661 bool eqwarn, bool fcall, bool retval_discarded, bool szof) 4662 { 4663 4664 if (tn == NULL) 4665 return; 4666 op_t op = tn->tn_op; 4667 if (op == NAME || op == CON || op == STRING) 4668 return; 4669 4670 lint_assert(has_operands(tn)); 4671 tnode_t *ln = tn->tn_left; 4672 tnode_t *rn = tn->tn_right; 4673 check_expr_op(tn, op, ln, 4674 szof, fcall, vctx, cond, retval_discarded, eqwarn); 4675 4676 const mod_t *mp = &modtab[op]; 4677 bool cvctx = mp->m_value_context; 4678 bool ccond = mp->m_compares_with_zero; 4679 bool eq = mp->m_warn_if_operand_eq && 4680 !ln->tn_parenthesized && 4681 rn != NULL && !rn->tn_parenthesized; 4682 4683 /* 4684 * Values of operands of ':' are not used if the type of at least 4685 * one of the operands (for GCC compatibility) is 'void'. 4686 * 4687 * XXX test/value context of QUEST should probably be used as 4688 * context for both operands of COLON. 4689 */ 4690 if (op == COLON && tn->tn_type->t_tspec == VOID) 4691 cvctx = ccond = false; 4692 bool discard = op == CVT && tn->tn_type->t_tspec == VOID; 4693 check_expr_misc(ln, cvctx, ccond, eq, op == CALL, discard, szof); 4694 4695 switch (op) { 4696 case PUSH: 4697 if (rn != NULL) 4698 check_expr_misc(rn, false, false, eq, false, false, 4699 szof); 4700 break; 4701 case LOGAND: 4702 case LOGOR: 4703 check_expr_misc(rn, false, true, eq, false, false, szof); 4704 break; 4705 case COLON: 4706 check_expr_misc(rn, cvctx, ccond, eq, false, false, szof); 4707 break; 4708 case COMMA: 4709 check_expr_misc(rn, vctx, cond, false, false, false, szof); 4710 break; 4711 default: 4712 if (mp->m_binary) 4713 check_expr_misc(rn, true, false, eq, false, false, 4714 szof); 4715 break; 4716 } 4717 } 4718 4719 /* 4720 * Return whether the expression can be used for static initialization. 4721 * 4722 * Constant initialization expressions must be constant or an address 4723 * of a static object with an optional offset. In the first case, 4724 * the result is returned in *offsp. In the second case, the static 4725 * object is returned in *symp and the offset in *offsp. 4726 * 4727 * The expression can consist of PLUS, MINUS, ADDR, NAME, STRING and 4728 * CON. Type conversions are allowed if they do not change binary 4729 * representation (including width). 4730 * 4731 * C99 6.6 "Constant expressions" 4732 * C99 6.7.8p4 restricts initializers for static storage duration 4733 */ 4734 bool 4735 constant_addr(const tnode_t *tn, const sym_t **symp, ptrdiff_t *offsp) 4736 { 4737 const sym_t *sym; 4738 ptrdiff_t offs1, offs2; 4739 tspec_t t, ot; 4740 4741 switch (tn->tn_op) { 4742 case MINUS: 4743 if (tn->tn_right->tn_op == CVT) 4744 return constant_addr(tn->tn_right, symp, offsp); 4745 else if (tn->tn_right->tn_op != CON) 4746 return false; 4747 /* FALLTHROUGH */ 4748 case PLUS: 4749 offs1 = offs2 = 0; 4750 if (tn->tn_left->tn_op == CON) { 4751 offs1 = (ptrdiff_t)tn->tn_left->tn_val.u.integer; 4752 if (!constant_addr(tn->tn_right, &sym, &offs2)) 4753 return false; 4754 } else if (tn->tn_right->tn_op == CON) { 4755 offs2 = (ptrdiff_t)tn->tn_right->tn_val.u.integer; 4756 if (tn->tn_op == MINUS) 4757 offs2 = -offs2; 4758 if (!constant_addr(tn->tn_left, &sym, &offs1)) 4759 return false; 4760 } else { 4761 return false; 4762 } 4763 *symp = sym; 4764 *offsp = offs1 + offs2; 4765 return true; 4766 case ADDR: 4767 if (tn->tn_left->tn_op == NAME) { 4768 *symp = tn->tn_left->tn_sym; 4769 *offsp = 0; 4770 return true; 4771 } else { 4772 /* 4773 * If this were the front end of a compiler, we would 4774 * return a label instead of 0, at least if 4775 * 'tn->tn_left->tn_op == STRING'. 4776 */ 4777 *symp = NULL; 4778 *offsp = 0; 4779 return true; 4780 } 4781 case CVT: 4782 t = tn->tn_type->t_tspec; 4783 ot = tn->tn_left->tn_type->t_tspec; 4784 if ((!is_integer(t) && t != PTR) || 4785 (!is_integer(ot) && ot != PTR)) { 4786 return false; 4787 } 4788 #if 0 4789 /*- 4790 * consider: 4791 * struct foo { 4792 * unsigned char a; 4793 * } f = { 4794 * (unsigned char)(unsigned long) 4795 * (&(((struct foo *)0)->a)) 4796 * }; 4797 * since psize(unsigned long) != psize(unsigned char), 4798 * this fails. 4799 */ 4800 else if (psize(t) != psize(ot)) 4801 return -1; 4802 #endif 4803 return constant_addr(tn->tn_left, symp, offsp); 4804 default: 4805 return false; 4806 } 4807 } 4808 4809 /* Append s2 to s1, then free s2. */ 4810 strg_t * 4811 cat_strings(strg_t *s1, strg_t *s2) 4812 { 4813 4814 if (s1->st_char != s2->st_char) { 4815 /* cannot concatenate wide and regular string literals */ 4816 error(292); 4817 return s1; 4818 } 4819 4820 size_t len1 = s1->st_len; 4821 size_t len2 = s2->st_len; 4822 size_t chsize = s1->st_char ? sizeof(char) : sizeof(wchar_t); 4823 size_t size1 = len1 * chsize; 4824 size_t size2 = (len2 + 1) * chsize; 4825 s1->st_mem = xrealloc(s1->st_mem, size1 + size2); 4826 memcpy((char *)s1->st_mem + size1, s2->st_mem, size2); 4827 free(s2->st_mem); 4828 4829 s1->st_len = len1 + len2; 4830 free(s2); 4831 4832 return s1; 4833 } 4834 4835 4836 typedef struct stmt_expr { 4837 memory_pool se_mem; 4838 sym_t *se_sym; 4839 struct stmt_expr *se_enclosing; 4840 } stmt_expr; 4841 4842 static stmt_expr *stmt_exprs; 4843 4844 void 4845 begin_statement_expr(void) 4846 { 4847 debug_enter(); 4848 4849 stmt_expr *se = xmalloc(sizeof(*se)); 4850 se->se_mem = expr_save_memory(); 4851 se->se_sym = NULL; 4852 se->se_enclosing = stmt_exprs; 4853 stmt_exprs = se; 4854 } 4855 4856 void 4857 do_statement_expr(tnode_t *tn) 4858 { 4859 block_level--; 4860 mem_block_level--; 4861 stmt_exprs->se_sym = tn != NULL 4862 ? mktempsym(block_dup_type(tn->tn_type)) 4863 : NULL; /* after a syntax error */ 4864 mem_block_level++; 4865 block_level++; 4866 /* '({ ... })' is a GCC extension */ 4867 gnuism(320); 4868 } 4869 4870 tnode_t * 4871 end_statement_expr(void) 4872 { 4873 tnode_t *tn; 4874 4875 stmt_expr *se = stmt_exprs; 4876 if (se->se_sym == NULL) { 4877 tn = NULL; /* after a syntax error */ 4878 goto end; 4879 } 4880 4881 tn = build_name(se->se_sym, false); 4882 (void)expr_save_memory(); /* leak */ 4883 expr_restore_memory(se->se_mem); 4884 stmt_exprs = se->se_enclosing; 4885 free(se); 4886 4887 end: 4888 debug_leave(); 4889 return tn; 4890 } 4891 4892 bool 4893 in_statement_expr(void) 4894 { 4895 return stmt_exprs != NULL; 4896 } 4897
Indexes created Mon Sep 22 13:09:51 GMT 2025