tree.c revision 1.548
1 /* $NetBSD: tree.c,v 1.548 2023/07/07 06:03:31 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 1.548 2023/07/07 06:03:31 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 const char * 86 op_name(op_t op) 87 { 88 return modtab[op].m_name; 89 } 90 91 static unsigned 92 width_in_bits(const type_t *tp) 93 { 94 95 lint_assert(is_integer(tp->t_tspec)); 96 return tp->t_bitfield 97 ? tp->t_bit_field_width 98 : portable_size_in_bits(tp->t_tspec); 99 } 100 101 static bool 102 ic_maybe_signed(const type_t *tp, const integer_constraints *ic) 103 { 104 return !is_uinteger(tp->t_tspec) && ic->bclr >> 63 == 0; 105 } 106 107 static integer_constraints 108 ic_any(const type_t *tp) 109 { 110 integer_constraints c; 111 112 uint64_t vbits = value_bits(width_in_bits(tp)); 113 if (is_uinteger(tp->t_tspec)) { 114 c.smin = INT64_MIN; 115 c.smax = INT64_MAX; 116 c.umin = 0; 117 c.umax = vbits; 118 c.bset = 0; 119 c.bclr = ~c.umax; 120 } else { 121 c.smin = (int64_t)-1 - (int64_t)(vbits >> 1); 122 c.smax = (int64_t)(vbits >> 1); 123 c.umin = 0; 124 c.umax = UINT64_MAX; 125 c.bset = 0; 126 c.bclr = 0; 127 } 128 return c; 129 } 130 131 static integer_constraints 132 ic_con(const type_t *tp, const val_t *v) 133 { 134 integer_constraints c; 135 136 lint_assert(is_integer(tp->t_tspec)); 137 int64_t si = v->u.integer; 138 uint64_t ui = (uint64_t)si; 139 c.smin = si; 140 c.smax = si; 141 c.umin = ui; 142 c.umax = ui; 143 c.bset = ui; 144 c.bclr = ~ui; 145 return c; 146 } 147 148 static integer_constraints 149 ic_cvt(const type_t *ntp, const type_t *otp, integer_constraints a) 150 { 151 unsigned nw = width_in_bits(ntp); 152 unsigned ow = width_in_bits(otp); 153 bool nu = is_uinteger(ntp->t_tspec); 154 bool ou = is_uinteger(otp->t_tspec); 155 156 if (nw >= ow && nu == ou) 157 return a; 158 if (nw > ow && ou) 159 return a; 160 return ic_any(ntp); 161 } 162 163 static integer_constraints 164 ic_bitand(integer_constraints a, integer_constraints b) 165 { 166 integer_constraints c; 167 168 c.smin = INT64_MIN; 169 c.smax = INT64_MAX; 170 c.umin = 0; 171 c.umax = UINT64_MAX; 172 c.bset = a.bset & b.bset; 173 c.bclr = a.bclr | b.bclr; 174 return c; 175 } 176 177 static integer_constraints 178 ic_bitor(integer_constraints a, integer_constraints b) 179 { 180 integer_constraints c; 181 182 c.smin = INT64_MIN; 183 c.smax = INT64_MAX; 184 c.umin = 0; 185 c.umax = UINT64_MAX; 186 c.bset = a.bset | b.bset; 187 c.bclr = a.bclr & b.bclr; 188 return c; 189 } 190 191 static integer_constraints 192 ic_mod(const type_t *tp, integer_constraints a, integer_constraints b) 193 { 194 integer_constraints c; 195 196 if (ic_maybe_signed(tp, &a) || ic_maybe_signed(tp, &b)) 197 return ic_any(tp); 198 199 c.smin = INT64_MIN; 200 c.smax = INT64_MAX; 201 c.umin = 0; 202 c.umax = b.umax - 1; 203 c.bset = 0; 204 c.bclr = ~u64_fill_right(c.umax); 205 return c; 206 } 207 208 static integer_constraints 209 ic_shl(const type_t *tp, integer_constraints a, integer_constraints b) 210 { 211 integer_constraints c; 212 unsigned int amount; 213 214 if (ic_maybe_signed(tp, &a)) 215 return ic_any(tp); 216 217 if (b.smin == b.smax && b.smin >= 0 && b.smin < 64) 218 amount = (unsigned int)b.smin; 219 else if (b.umin == b.umax && b.umin < 64) 220 amount = (unsigned int)b.umin; 221 else 222 return ic_any(tp); 223 224 c.smin = INT64_MIN; 225 c.smax = INT64_MAX; 226 c.umin = 0; 227 c.umax = UINT64_MAX; 228 c.bset = a.bset << amount; 229 c.bclr = a.bclr << amount | (((uint64_t)1 << amount) - 1); 230 return c; 231 } 232 233 static integer_constraints 234 ic_shr(const type_t *tp, integer_constraints a, integer_constraints b) 235 { 236 integer_constraints c; 237 unsigned int amount; 238 239 if (ic_maybe_signed(tp, &a)) 240 return ic_any(tp); 241 242 if (b.smin == b.smax && b.smin >= 0 && b.smin < 64) 243 amount = (unsigned int)b.smin; 244 else if (b.umin == b.umax && b.umin < 64) 245 amount = (unsigned int)b.umin; 246 else 247 return ic_any(tp); 248 249 c.smin = INT64_MIN; 250 c.smax = INT64_MAX; 251 c.umin = 0; 252 c.umax = UINT64_MAX; 253 c.bset = a.bset >> amount; 254 c.bclr = a.bclr >> amount | ~(~(uint64_t)0 >> amount); 255 return c; 256 } 257 258 static integer_constraints 259 ic_cond(integer_constraints a, integer_constraints b) 260 { 261 integer_constraints c; 262 263 c.smin = a.smin < b.smin ? a.smin : b.smin; 264 c.smax = a.smax > b.smax ? a.smax : b.smax; 265 c.umin = a.umin < b.umin ? a.umin : b.umin; 266 c.umax = a.umax > b.umax ? a.umax : b.umax; 267 c.bset = a.bset | b.bset; 268 c.bclr = a.bclr & b.bclr; 269 return c; 270 } 271 272 static integer_constraints 273 ic_expr(const tnode_t *tn) 274 { 275 integer_constraints lc, rc; 276 277 lint_assert(is_integer(tn->tn_type->t_tspec)); 278 279 switch (tn->tn_op) { 280 case CON: 281 return ic_con(tn->tn_type, &tn->tn_val); 282 case CVT: 283 if (!is_integer(tn->tn_left->tn_type->t_tspec)) 284 return ic_any(tn->tn_type); 285 lc = ic_expr(tn->tn_left); 286 return ic_cvt(tn->tn_type, tn->tn_left->tn_type, lc); 287 case MOD: 288 lc = ic_expr(before_conversion(tn->tn_left)); 289 rc = ic_expr(before_conversion(tn->tn_right)); 290 return ic_mod(tn->tn_type, lc, rc); 291 case SHL: 292 lc = ic_expr(tn->tn_left); 293 rc = ic_expr(tn->tn_right); 294 return ic_shl(tn->tn_type, lc, rc); 295 case SHR: 296 lc = ic_expr(tn->tn_left); 297 rc = ic_expr(tn->tn_right); 298 return ic_shr(tn->tn_type, lc, rc); 299 case BITAND: 300 lc = ic_expr(tn->tn_left); 301 rc = ic_expr(tn->tn_right); 302 return ic_bitand(lc, rc); 303 case BITOR: 304 lc = ic_expr(tn->tn_left); 305 rc = ic_expr(tn->tn_right); 306 return ic_bitor(lc, rc); 307 case QUEST: 308 lc = ic_expr(tn->tn_right->tn_left); 309 rc = ic_expr(tn->tn_right->tn_right); 310 return ic_cond(lc, rc); 311 default: 312 return ic_any(tn->tn_type); 313 } 314 } 315 316 /* Build 'pointer to tp', 'array of tp' or 'function returning tp'. */ 317 type_t * 318 block_derive_type(type_t *tp, tspec_t t) 319 { 320 type_t *tp2; 321 322 tp2 = block_zero_alloc(sizeof(*tp2)); 323 tp2->t_tspec = t; 324 tp2->t_subt = tp; 325 return tp2; 326 } 327 328 /* 329 * Derive 'pointer to tp' or 'function returning tp'. 330 * The memory is freed at the end of the current expression. 331 */ 332 type_t * 333 expr_derive_type(type_t *tp, tspec_t t) 334 { 335 type_t *tp2; 336 337 tp2 = expr_zero_alloc(sizeof(*tp2)); 338 tp2->t_tspec = t; 339 tp2->t_subt = tp; 340 return tp2; 341 } 342 343 /* 344 * Build and initialize a new node. 345 */ 346 static tnode_t * 347 new_tnode(op_t op, bool sys, type_t *type, tnode_t *ln, tnode_t *rn) 348 { 349 350 tnode_t *ntn = expr_alloc_tnode(); 351 ntn->tn_op = op; 352 ntn->tn_type = type; 353 ntn->tn_sys = sys; 354 ntn->tn_left = ln; 355 ntn->tn_right = rn; 356 357 if (op == INDIR || op == FSEL) { 358 lint_assert(ln->tn_type->t_tspec == PTR); 359 tspec_t t = ln->tn_type->t_subt->t_tspec; 360 if (t != FUNC && t != VOID) 361 ntn->tn_lvalue = true; 362 } 363 364 return ntn; 365 } 366 367 /* 368 * Create a node for a constant. 369 */ 370 tnode_t * 371 build_constant(type_t *tp, val_t *v) 372 { 373 374 tnode_t *n = expr_alloc_tnode(); 375 n->tn_op = CON; 376 n->tn_type = tp; 377 n->tn_val = *v; 378 n->tn_val.v_tspec = tp->t_tspec; 379 free(v); 380 return n; 381 } 382 383 static tnode_t * 384 build_integer_constant(tspec_t t, int64_t si) 385 { 386 387 tnode_t *n = expr_alloc_tnode(); 388 n->tn_op = CON; 389 n->tn_type = gettyp(t); 390 n->tn_val.v_tspec = t; 391 n->tn_val.v_unsigned_since_c90 = false; 392 n->tn_val.v_char_constant = false; 393 n->tn_val.u.integer = si; 394 return n; 395 } 396 397 static void 398 fallback_symbol(sym_t *sym) 399 { 400 401 if (Tflag && fallback_symbol_strict_bool(sym)) 402 return; 403 404 if (block_level > 0 && (strcmp(sym->s_name, "__FUNCTION__") == 0 || 405 strcmp(sym->s_name, "__PRETTY_FUNCTION__") == 0)) { 406 /* __FUNCTION__/__PRETTY_FUNCTION__ is a GCC extension */ 407 gnuism(316); 408 sym->s_type = block_derive_type(gettyp(CHAR), PTR); 409 sym->s_type->t_const = true; 410 return; 411 } 412 413 if (block_level > 0 && strcmp(sym->s_name, "__func__") == 0) { 414 if (!allow_c99) 415 /* __func__ is a C99 feature */ 416 warning(317); 417 /* C11 6.4.2.2 */ 418 sym->s_type = block_derive_type(gettyp(CHAR), ARRAY); 419 sym->s_type->t_const = true; 420 sym->s_type->t_dim = (int)strlen(funcsym->s_name) + 1; 421 return; 422 } 423 424 /* '%s' undefined */ 425 error(99, sym->s_name); 426 } 427 428 /* 429 * Functions that are predeclared by GCC or other compilers can be called 430 * with arbitrary arguments. Since lint usually runs after a successful 431 * compilation, it's the compiler's job to catch any errors. 432 */ 433 bool 434 is_compiler_builtin(const char *name) 435 { 436 /* https://gcc.gnu.org/onlinedocs/gcc/C-Extensions.html */ 437 if (allow_gcc) { 438 if (strncmp(name, "__atomic_", 9) == 0 || 439 strncmp(name, "__builtin_", 10) == 0 || 440 strcmp(name, "alloca") == 0 || 441 /* obsolete but still in use, as of 2021 */ 442 strncmp(name, "__sync_", 7) == 0) 443 return true; 444 } 445 446 /* https://software.intel.com/sites/landingpage/IntrinsicsGuide/ */ 447 if (strncmp(name, "_mm_", 4) == 0) 448 return true; 449 450 return false; 451 } 452 453 /* https://gcc.gnu.org/onlinedocs/gcc/Integer-Overflow-Builtins.html */ 454 static bool 455 is_gcc_bool_builtin(const char *name) 456 { 457 return strncmp(name, "__builtin_", 10) == 0 && 458 (str_ends_with(name, "_overflow") || 459 str_ends_with(name, "_overflow_p")); 460 } 461 462 static void 463 build_name_call(sym_t *sym) 464 { 465 466 if (is_compiler_builtin(sym->s_name)) { 467 /* 468 * Do not warn about these, just assume that 469 * they are regular functions compatible with 470 * non-prototype calling conventions. 471 */ 472 if (allow_gcc && is_gcc_bool_builtin(sym->s_name)) 473 sym->s_type = gettyp(BOOL); 474 } else if (allow_c99) { 475 /* function '%s' implicitly declared to return int */ 476 error(215, sym->s_name); 477 } else if (!allow_trad) { 478 /* function '%s' implicitly declared to return int */ 479 warning(215, sym->s_name); 480 } 481 482 /* XXX if !allow_c90, the symbol should be exported to level 0 */ 483 sym->s_type = block_derive_type(sym->s_type, FUNC); 484 } 485 486 /* Create a node for a name (symbol table entry). */ 487 tnode_t * 488 build_name(sym_t *sym, bool is_funcname) 489 { 490 491 if (sym->s_scl == NOSCL && !in_gcc_attribute) { 492 sym->s_scl = EXTERN; 493 sym->s_def = DECL; 494 if (is_funcname) 495 build_name_call(sym); 496 else 497 fallback_symbol(sym); 498 } 499 500 lint_assert(sym->s_kind == FVFT || sym->s_kind == FMEMBER); 501 502 tnode_t *n = expr_alloc_tnode(); 503 n->tn_type = sym->s_type; 504 if (sym->s_scl == BOOL_CONST) { 505 n->tn_op = CON; 506 n->tn_val.v_tspec = BOOL; 507 n->tn_val.v_unsigned_since_c90 = false; 508 n->tn_val.v_char_constant = false; 509 n->tn_val.u.integer = sym->u.s_bool_constant ? 1 : 0; 510 } else if (sym->s_scl == ENUM_CONST) { 511 n->tn_op = CON; 512 n->tn_val.v_tspec = INT; /* ENUM is in n->tn_type */ 513 n->tn_val.v_unsigned_since_c90 = false; 514 n->tn_val.v_char_constant = false; 515 n->tn_val.u.integer = sym->u.s_enum_constant; 516 } else { 517 n->tn_op = NAME; 518 n->tn_sym = sym; 519 if (sym->s_kind == FVFT && sym->s_type->t_tspec != FUNC) 520 n->tn_lvalue = true; 521 } 522 523 return n; 524 } 525 526 tnode_t * 527 build_string(strg_t *strg) 528 { 529 size_t len = strg->st_len; 530 531 type_t *tp = expr_zero_alloc(sizeof(*tp)); 532 tp->t_tspec = ARRAY; 533 tp->t_subt = gettyp(strg->st_char ? CHAR : WCHAR); 534 tp->t_dim = (int)(len + 1); 535 536 tnode_t *n = expr_alloc_tnode(); 537 n->tn_op = STRING; 538 n->tn_type = tp; 539 n->tn_lvalue = true; 540 541 n->tn_string = expr_zero_alloc(sizeof(*n->tn_string)); 542 n->tn_string->st_char = strg->st_char; 543 n->tn_string->st_len = len; 544 545 size_t chsize = strg->st_char ? sizeof(char) : sizeof(wchar_t); 546 size_t size = (len + 1) * chsize; 547 n->tn_string->st_mem = expr_zero_alloc(size); 548 (void)memcpy(n->tn_string->st_mem, strg->st_mem, size); 549 free(strg->st_mem); 550 free(strg); 551 552 return n; 553 } 554 555 tnode_t * 556 build_generic_selection(const tnode_t *expr, 557 struct generic_association *sel) 558 { 559 tnode_t *default_result = NULL; 560 561 for (; sel != NULL; sel = sel->ga_prev) { 562 if (expr != NULL && 563 types_compatible(sel->ga_arg, expr->tn_type, 564 false, false, NULL)) 565 return sel->ga_result; 566 else if (sel->ga_arg == NULL) 567 default_result = sel->ga_result; 568 } 569 return default_result; 570 } 571 572 static bool 573 is_out_of_char_range(const tnode_t *tn) 574 { 575 return tn->tn_op == CON && 576 !tn->tn_val.v_char_constant && 577 !(0 <= tn->tn_val.u.integer && 578 tn->tn_val.u.integer < 1 << (CHAR_SIZE - 1)); 579 } 580 581 static void 582 check_integer_comparison(op_t op, tnode_t *ln, tnode_t *rn) 583 { 584 585 tspec_t lt = ln->tn_type->t_tspec; 586 tspec_t rt = rn->tn_type->t_tspec; 587 588 if (ln->tn_op != CON && rn->tn_op != CON) 589 return; 590 591 if (!is_integer(lt) || !is_integer(rt)) 592 return; 593 594 if (any_query_enabled && !in_system_header) { 595 if (lt == CHAR && rn->tn_op == CON && 596 !rn->tn_val.v_char_constant) { 597 /* comparison '%s' of 'char' with plain integer %d */ 598 query_message(14, 599 op_name(op), (int)rn->tn_val.u.integer); 600 } 601 if (rt == CHAR && ln->tn_op == CON && 602 !ln->tn_val.v_char_constant) { 603 /* comparison '%s' of 'char' with plain integer %d */ 604 query_message(14, 605 op_name(op), (int)ln->tn_val.u.integer); 606 } 607 } 608 609 if (hflag || pflag) { 610 if (lt == CHAR && is_out_of_char_range(rn)) { 611 char buf[128]; 612 (void)snprintf(buf, sizeof(buf), "%s %d", 613 op_name(op), (int)rn->tn_val.u.integer); 614 /* nonportable character comparison '%s' */ 615 warning(230, buf); 616 return; 617 } 618 if (rt == CHAR && is_out_of_char_range(ln)) { 619 char buf[128]; 620 (void)snprintf(buf, sizeof(buf), "%d %s ?", 621 (int)ln->tn_val.u.integer, op_name(op)); 622 /* nonportable character comparison '%s' */ 623 warning(230, buf); 624 return; 625 } 626 } 627 628 if (is_uinteger(lt) && !is_uinteger(rt) && 629 rn->tn_op == CON && rn->tn_val.u.integer <= 0) { 630 if (rn->tn_val.u.integer < 0) { 631 /* operator '%s' compares '%s' with '%s' */ 632 warning(162, op_name(op), 633 type_name(ln->tn_type), "negative constant"); 634 } else if (op == LT || op == GE) { 635 /* operator '%s' compares '%s' with '%s' */ 636 warning(162, op_name(op), type_name(ln->tn_type), "0"); 637 } 638 return; 639 } 640 if (is_uinteger(rt) && !is_uinteger(lt) && 641 ln->tn_op == CON && ln->tn_val.u.integer <= 0) { 642 if (ln->tn_val.u.integer < 0) { 643 /* operator '%s' compares '%s' with '%s' */ 644 warning(162, op_name(op), 645 "negative constant", type_name(rn->tn_type)); 646 } else if (op == GT || op == LE) { 647 /* operator '%s' compares '%s' with '%s' */ 648 warning(162, op_name(op), "0", type_name(rn->tn_type)); 649 } 650 return; 651 } 652 } 653 654 static const tspec_t arith_rank[] = { 655 LDOUBLE, DOUBLE, FLOAT, 656 #ifdef INT128_SIZE 657 UINT128, INT128, 658 #endif 659 ULLONG, LLONG, 660 ULONG, LONG, 661 UINT, INT, 662 }; 663 664 /* Keep unsigned in traditional C */ 665 static tspec_t 666 usual_arithmetic_conversion_trad(tspec_t lt, tspec_t rt) 667 { 668 669 size_t i; 670 for (i = 0; arith_rank[i] != INT; i++) 671 if (lt == arith_rank[i] || rt == arith_rank[i]) 672 break; 673 674 tspec_t t = arith_rank[i]; 675 if (is_uinteger(lt) || is_uinteger(rt)) 676 if (is_integer(t) && !is_uinteger(t)) 677 return unsigned_type(t); 678 return t; 679 } 680 681 static tspec_t 682 usual_arithmetic_conversion_c90(tspec_t lt, tspec_t rt) 683 { 684 685 if (lt == rt) 686 return lt; 687 688 if (lt == LCOMPLEX || rt == LCOMPLEX) 689 return LCOMPLEX; 690 if (lt == DCOMPLEX || rt == DCOMPLEX) 691 return DCOMPLEX; 692 if (lt == FCOMPLEX || rt == FCOMPLEX) 693 return FCOMPLEX; 694 if (lt == LDOUBLE || rt == LDOUBLE) 695 return LDOUBLE; 696 if (lt == DOUBLE || rt == DOUBLE) 697 return DOUBLE; 698 if (lt == FLOAT || rt == FLOAT) 699 return FLOAT; 700 701 /* 702 * If type A has more bits than type B, it should be able to hold all 703 * possible values of type B. 704 */ 705 if (size_in_bits(lt) > size_in_bits(rt)) 706 return lt; 707 if (size_in_bits(lt) < size_in_bits(rt)) 708 return rt; 709 710 size_t i; 711 for (i = 3; arith_rank[i] != INT; i++) 712 if (arith_rank[i] == lt || arith_rank[i] == rt) 713 break; 714 if ((is_uinteger(lt) || is_uinteger(rt)) && 715 !is_uinteger(arith_rank[i])) 716 i--; 717 return arith_rank[i]; 718 } 719 720 static tnode_t * 721 apply_usual_arithmetic_conversions(op_t op, tnode_t *tn, tspec_t t) 722 { 723 type_t *ntp = expr_dup_type(tn->tn_type); 724 ntp->t_tspec = t; 725 if (tn->tn_op != CON) { 726 /* usual arithmetic conversion for '%s' from '%s' to '%s' */ 727 query_message(4, op_name(op), 728 type_name(tn->tn_type), type_name(ntp)); 729 } 730 return convert(op, 0, ntp, tn); 731 } 732 733 /* 734 * Apply the "usual arithmetic conversions" (C99 6.3.1.8), which gives both 735 * operands the same type. 736 */ 737 static void 738 balance(op_t op, tnode_t **lnp, tnode_t **rnp) 739 { 740 741 tspec_t lt = (*lnp)->tn_type->t_tspec; 742 tspec_t rt = (*rnp)->tn_type->t_tspec; 743 if (!is_arithmetic(lt) || !is_arithmetic(rt)) 744 return; 745 746 tspec_t t = allow_c90 747 ? usual_arithmetic_conversion_c90(lt, rt) 748 : usual_arithmetic_conversion_trad(lt, rt); 749 750 if (t != lt) 751 *lnp = apply_usual_arithmetic_conversions(op, *lnp, t); 752 if (t != rt) 753 *rnp = apply_usual_arithmetic_conversions(op, *rnp, t); 754 } 755 756 /* 757 * Create a tree node for the unary & operator 758 */ 759 static tnode_t * 760 build_address(bool sys, tnode_t *tn, bool noign) 761 { 762 tspec_t t; 763 764 if (!noign && ((t = tn->tn_type->t_tspec) == ARRAY || t == FUNC)) { 765 if (!allow_c90) 766 /* '&' before array or function: ignored */ 767 warning(127); 768 return tn; 769 } 770 771 /* eliminate &* */ 772 if (tn->tn_op == INDIR && 773 tn->tn_left->tn_type->t_tspec == PTR && 774 tn->tn_left->tn_type->t_subt == tn->tn_type) { 775 return tn->tn_left; 776 } 777 778 return new_tnode(ADDR, sys, expr_derive_type(tn->tn_type, PTR), 779 tn, NULL); 780 } 781 782 /* 783 * XXX 784 * Note: There appear to be a number of bugs in detecting overflow in 785 * this function. An audit and a set of proper regression tests are needed. 786 * --Perry Metzger, Nov. 16, 2001 787 */ 788 /* 789 * Do only as much as necessary to compute constant expressions. 790 * Called only if the operator allows folding and all operands are constants. 791 */ 792 static tnode_t * 793 fold(tnode_t *tn) 794 { 795 796 val_t *v = xcalloc(1, sizeof(*v)); 797 v->v_tspec = tn->tn_type->t_tspec; 798 799 tspec_t t = tn->tn_left->tn_type->t_tspec; 800 bool utyp = !is_integer(t) || is_uinteger(t); 801 int64_t sl = tn->tn_left->tn_val.u.integer, sr = 0; 802 uint64_t ul = sl, ur = 0; 803 if (is_binary(tn)) 804 ur = sr = tn->tn_right->tn_val.u.integer; 805 806 int64_t mask = (int64_t)value_bits(size_in_bits(t)); 807 bool ovfl = false; 808 809 int64_t si; 810 switch (tn->tn_op) { 811 case UPLUS: 812 si = sl; 813 break; 814 case UMINUS: 815 si = sl == INT64_MIN ? sl : -sl; 816 if (sl != 0 && msb(si, t) == msb(sl, t)) 817 ovfl = true; 818 break; 819 case COMPL: 820 si = ~sl; 821 break; 822 case MULT: 823 if (utyp) { 824 si = (int64_t)(ul * ur); 825 if (si != (si & mask)) 826 ovfl = true; 827 else if ((ul != 0) && ((si / ul) != ur)) 828 ovfl = true; 829 } else { 830 si = sl * sr; 831 if (msb(si, t) != (msb(sl, t) ^ msb(sr, t))) 832 ovfl = true; 833 } 834 break; 835 case DIV: 836 if (sr == 0) { 837 /* division by 0 */ 838 error(139); 839 si = utyp ? -1 : INT64_MAX; 840 } else { 841 si = utyp ? (int64_t)(ul / ur) : sl / sr; 842 } 843 break; 844 case MOD: 845 if (sr == 0) { 846 /* modulus by 0 */ 847 error(140); 848 si = 0; 849 } else { 850 si = utyp ? (int64_t)(ul % ur) : sl % sr; 851 } 852 break; 853 case PLUS: 854 si = utyp ? (int64_t)(ul + ur) : sl + sr; 855 if (msb(sl, t) && msb(sr, t) && !msb(si, t)) 856 ovfl = true; 857 if (!utyp && !msb(sl, t) && !msb(sr, t) && msb(si, t)) 858 ovfl = true; 859 break; 860 case MINUS: 861 si = utyp ? (int64_t)(ul - ur) : sl - sr; 862 if (!utyp && msb(sl, t) && !msb(sr, t) && !msb(si, t)) 863 ovfl = true; 864 if (!msb(sl, t) && msb(sr, t) && msb(si, t)) 865 ovfl = true; 866 break; 867 case SHL: 868 /* TODO: warn about out-of-bounds 'sr'. */ 869 /* TODO: warn about overflow in signed '<<'. */ 870 si = utyp ? (int64_t)(ul << (sr & 63)) : sl << (sr & 63); 871 break; 872 case SHR: 873 /* 874 * The sign must be explicitly extended because 875 * shifts of signed values are implementation dependent. 876 */ 877 /* TODO: warn about out-of-bounds 'sr'. */ 878 si = (int64_t)(ul >> (sr & 63)); 879 si = convert_integer(si, t, size_in_bits(t) - (int)sr); 880 break; 881 case LT: 882 si = (utyp ? ul < ur : sl < sr) ? 1 : 0; 883 break; 884 case LE: 885 si = (utyp ? ul <= ur : sl <= sr) ? 1 : 0; 886 break; 887 case GE: 888 si = (utyp ? ul >= ur : sl >= sr) ? 1 : 0; 889 break; 890 case GT: 891 si = (utyp ? ul > ur : sl > sr) ? 1 : 0; 892 break; 893 case EQ: 894 si = (utyp ? ul == ur : sl == sr) ? 1 : 0; 895 break; 896 case NE: 897 si = (utyp ? ul != ur : sl != sr) ? 1 : 0; 898 break; 899 case BITAND: 900 si = utyp ? (int64_t)(ul & ur) : sl & sr; 901 break; 902 case BITXOR: 903 si = utyp ? (int64_t)(ul ^ ur) : sl ^ sr; 904 break; 905 case BITOR: 906 si = utyp ? (int64_t)(ul | ur) : sl | sr; 907 break; 908 default: 909 lint_assert(/*CONSTCOND*/false); 910 } 911 912 /* XXX: The overflow check does not work for 64-bit integers. */ 913 if (ovfl || 914 ((uint64_t)(si | mask) != ~(uint64_t)0 && (si & ~mask) != 0)) { 915 if (hflag) 916 /* integer overflow detected, op '%s' */ 917 warning(141, op_name(tn->tn_op)); 918 } 919 920 v->u.integer = convert_integer(si, t, 0); 921 922 tnode_t *cn = build_constant(tn->tn_type, v); 923 if (tn->tn_left->tn_system_dependent) 924 cn->tn_system_dependent = true; 925 if (is_binary(tn) && tn->tn_right->tn_system_dependent) 926 cn->tn_system_dependent = true; 927 928 return cn; 929 } 930 931 /* 932 * Create a new node for one of the operators POINT and ARROW. 933 */ 934 static tnode_t * 935 build_struct_access(op_t op, bool sys, tnode_t *ln, tnode_t *rn) 936 { 937 938 lint_assert(rn->tn_op == NAME); 939 lint_assert(is_member(rn->tn_sym)); 940 941 /* 942 * Remember if the left operand is an lvalue (structure members 943 * are lvalues if and only if the structure itself is an lvalue). 944 */ 945 bool nolval = op == POINT && !ln->tn_lvalue; 946 947 if (op == POINT) { 948 ln = build_address(sys, ln, true); 949 } else if (ln->tn_type->t_tspec != PTR) { 950 lint_assert(!allow_c90); 951 lint_assert(is_integer(ln->tn_type->t_tspec)); 952 ln = convert(NOOP, 0, expr_derive_type(gettyp(VOID), PTR), ln); 953 } 954 955 tnode_t *ctn = build_integer_constant(PTRDIFF_TSPEC, 956 rn->tn_sym->u.s_member.sm_offset_in_bits / CHAR_SIZE); 957 958 type_t *ptr_tp = expr_derive_type(rn->tn_type, PTR); 959 tnode_t *ntn = new_tnode(PLUS, sys, ptr_tp, ln, ctn); 960 if (ln->tn_op == CON) 961 ntn = fold(ntn); 962 963 if (rn->tn_type->t_bitfield) { 964 ntn = new_tnode(FSEL, sys, ntn->tn_type->t_subt, ntn, NULL); 965 } else { 966 ntn = new_tnode(INDIR, sys, ntn->tn_type->t_subt, ntn, NULL); 967 } 968 969 if (nolval) 970 ntn->tn_lvalue = false; 971 972 return ntn; 973 } 974 975 /* 976 * Get the size in bytes of type tp->t_subt, as a constant expression of type 977 * ptrdiff_t as seen from the target platform. 978 */ 979 static tnode_t * 980 subt_size_in_bytes(type_t *tp) 981 { 982 983 lint_assert(tp->t_tspec == PTR); 984 tp = tp->t_subt; 985 986 int elem = 1; 987 while (tp->t_tspec == ARRAY) { 988 elem *= tp->t_dim; 989 tp = tp->t_subt; 990 } 991 992 int elsz_in_bits = 0; 993 switch (tp->t_tspec) { 994 case FUNC: 995 /* pointer to function is not allowed here */ 996 error(110); 997 break; 998 case VOID: 999 /* cannot do pointer arithmetic on operand of unknown size */ 1000 gnuism(136); 1001 break; 1002 case STRUCT: 1003 case UNION: 1004 if ((elsz_in_bits = (int)tp->t_sou->sou_size_in_bits) == 0) 1005 /* cannot do pointer arithmetic on operand of ... */ 1006 error(136); 1007 break; 1008 case ENUM: 1009 if (is_incomplete(tp)) { 1010 /* cannot do pointer arithmetic on operand of ... */ 1011 warning(136); 1012 } 1013 /* FALLTHROUGH */ 1014 default: 1015 if ((elsz_in_bits = size_in_bits(tp->t_tspec)) == 0) { 1016 /* cannot do pointer arithmetic on operand of ... */ 1017 error(136); 1018 } else { 1019 lint_assert(elsz_in_bits != -1); 1020 } 1021 break; 1022 } 1023 1024 if (elem == 0 && elsz_in_bits != 0) { 1025 /* cannot do pointer arithmetic on operand of unknown size */ 1026 error(136); 1027 } 1028 1029 if (elsz_in_bits == 0) 1030 elsz_in_bits = CHAR_SIZE; 1031 1032 return build_integer_constant(PTRDIFF_TSPEC, 1033 (int64_t)(elem * elsz_in_bits / CHAR_SIZE)); 1034 } 1035 1036 /* 1037 * Create a node for INCAFT, INCBEF, DECAFT and DECBEF. 1038 */ 1039 static tnode_t * 1040 build_prepost_incdec(op_t op, bool sys, tnode_t *ln) 1041 { 1042 1043 lint_assert(ln != NULL); 1044 tnode_t *cn = ln->tn_type->t_tspec == PTR 1045 ? subt_size_in_bytes(ln->tn_type) 1046 : build_integer_constant(INT, 1); 1047 return new_tnode(op, sys, ln->tn_type, ln, cn); 1048 } 1049 1050 static void 1051 check_enum_array_index(const tnode_t *ln, const tnode_t *rn) 1052 { 1053 1054 if (ln->tn_op != ADDR || ln->tn_left->tn_op != NAME) 1055 return; 1056 1057 const type_t *ltp = ln->tn_left->tn_type; 1058 if (ltp->t_tspec != ARRAY || ltp->t_incomplete_array) 1059 return; 1060 1061 if (rn->tn_op != CVT || !rn->tn_type->t_is_enum) 1062 return; 1063 if (rn->tn_left->tn_op != LOAD) 1064 return; 1065 1066 const type_t *rtp = rn->tn_left->tn_type; 1067 const sym_t *ec = rtp->t_enum->en_first_enumerator; 1068 const sym_t *max_ec = ec; 1069 lint_assert(ec != NULL); 1070 for (ec = ec->s_next; ec != NULL; ec = ec->s_next) 1071 if (ec->u.s_enum_constant > max_ec->u.s_enum_constant) 1072 max_ec = ec; 1073 1074 int64_t max_enum_value = max_ec->u.s_enum_constant; 1075 lint_assert(INT_MIN <= max_enum_value && max_enum_value <= INT_MAX); 1076 1077 int max_array_index = ltp->t_dim - 1; 1078 if (max_enum_value == max_array_index) 1079 return; 1080 1081 /* 1082 * If the name of the largest enum constant contains 'MAX' or 'NUM', 1083 * that constant is typically not part of the allowed enum values but 1084 * a marker for the number of actual enum values. 1085 */ 1086 if (max_enum_value == max_array_index + 1 && 1087 (strstr(max_ec->s_name, "MAX") != NULL || 1088 strstr(max_ec->s_name, "max") != NULL || 1089 strstr(max_ec->s_name, "NUM") != NULL || 1090 strstr(max_ec->s_name, "num") != NULL)) 1091 return; 1092 1093 /* maximum value %d of '%s' does not match maximum array index %d */ 1094 warning(348, (int)max_enum_value, type_name(rtp), max_array_index); 1095 print_previous_declaration(max_ec); 1096 } 1097 1098 /* 1099 * Create a node for operators PLUS and MINUS. 1100 */ 1101 static tnode_t * 1102 build_plus_minus(op_t op, bool sys, tnode_t *ln, tnode_t *rn) 1103 { 1104 1105 /* If pointer and integer, move the pointer to the left. */ 1106 if (rn->tn_type->t_tspec == PTR && is_integer(ln->tn_type->t_tspec)) { 1107 tnode_t *tmp = ln; 1108 ln = rn; 1109 rn = tmp; 1110 /* pointer addition has integer on the left-hand side */ 1111 query_message(5); 1112 } 1113 1114 /* pointer +- integer */ 1115 if (ln->tn_type->t_tspec == PTR && rn->tn_type->t_tspec != PTR) { 1116 lint_assert(is_integer(rn->tn_type->t_tspec)); 1117 1118 check_ctype_macro_invocation(ln, rn); 1119 check_enum_array_index(ln, rn); 1120 1121 tnode_t *elsz = subt_size_in_bytes(ln->tn_type); 1122 if (rn->tn_type->t_tspec != elsz->tn_type->t_tspec) 1123 rn = convert(NOOP, 0, elsz->tn_type, rn); 1124 1125 tnode_t *prod = new_tnode(MULT, sys, rn->tn_type, rn, elsz); 1126 if (rn->tn_op == CON) 1127 prod = fold(prod); 1128 1129 return new_tnode(op, sys, ln->tn_type, ln, prod); 1130 } 1131 1132 /* pointer - pointer */ 1133 if (rn->tn_type->t_tspec == PTR) { 1134 lint_assert(ln->tn_type->t_tspec == PTR); 1135 lint_assert(op == MINUS); 1136 1137 type_t *ptrdiff = gettyp(PTRDIFF_TSPEC); 1138 tnode_t *raw_diff = new_tnode(op, sys, ptrdiff, ln, rn); 1139 if (ln->tn_op == CON && rn->tn_op == CON) 1140 raw_diff = fold(raw_diff); 1141 1142 tnode_t *elsz = subt_size_in_bytes(ln->tn_type); 1143 balance(NOOP, &raw_diff, &elsz); 1144 1145 return new_tnode(DIV, sys, ptrdiff, raw_diff, elsz); 1146 } 1147 1148 return new_tnode(op, sys, ln->tn_type, ln, rn); 1149 } 1150 1151 /* 1152 * Create a node for operators SHL and SHR. 1153 */ 1154 static tnode_t * 1155 build_bit_shift(op_t op, bool sys, tnode_t *ln, tnode_t *rn) 1156 { 1157 1158 if (!allow_c90 && rn->tn_type->t_tspec != INT) 1159 rn = convert(NOOP, 0, gettyp(INT), rn); 1160 return new_tnode(op, sys, ln->tn_type, ln, rn); 1161 } 1162 1163 static bool 1164 is_null_pointer(const tnode_t *tn) 1165 { 1166 tspec_t t = tn->tn_type->t_tspec; 1167 1168 return ((t == PTR && tn->tn_type->t_subt->t_tspec == VOID) || 1169 is_integer(t)) 1170 && (tn->tn_op == CON && tn->tn_val.u.integer == 0); 1171 } 1172 1173 /* Return a type based on tp1, with added qualifiers from tp2. */ 1174 static type_t * 1175 merge_qualifiers(type_t *tp1, const type_t *tp2) 1176 { 1177 1178 lint_assert(tp1->t_tspec == PTR); 1179 lint_assert(tp2->t_tspec == PTR); 1180 1181 bool c1 = tp1->t_subt->t_const; 1182 bool c2 = tp2->t_subt->t_const; 1183 bool v1 = tp1->t_subt->t_volatile; 1184 bool v2 = tp2->t_subt->t_volatile; 1185 1186 if (c1 == (c1 | c2) && v1 == (v1 | v2)) 1187 return tp1; 1188 1189 type_t *nstp = expr_dup_type(tp1->t_subt); 1190 nstp->t_const |= c2; 1191 nstp->t_volatile |= v2; 1192 1193 type_t *ntp = expr_dup_type(tp1); 1194 ntp->t_subt = nstp; 1195 return ntp; 1196 } 1197 1198 /* See C99 6.5.15 "Conditional operator". */ 1199 static tnode_t * 1200 build_colon(bool sys, tnode_t *ln, tnode_t *rn) 1201 { 1202 1203 tspec_t lt = ln->tn_type->t_tspec; 1204 tspec_t rt = rn->tn_type->t_tspec; 1205 1206 type_t *tp; 1207 if (is_arithmetic(lt) && is_arithmetic(rt)) { 1208 /* The operands were already balanced in build_binary. */ 1209 tp = ln->tn_type; 1210 } else if (lt == BOOL && rt == BOOL) { 1211 tp = ln->tn_type; 1212 } else if (lt == VOID || rt == VOID) { 1213 tp = gettyp(VOID); 1214 } else if (is_struct_or_union(lt)) { 1215 /* Both types must be identical. */ 1216 lint_assert(is_struct_or_union(rt)); 1217 lint_assert(ln->tn_type->t_sou == rn->tn_type->t_sou); 1218 if (is_incomplete(ln->tn_type)) { 1219 /* unknown operand size, op '%s' */ 1220 error(138, op_name(COLON)); 1221 return NULL; 1222 } 1223 tp = ln->tn_type; 1224 } else if (lt == PTR && is_integer(rt)) { 1225 if (rt != PTRDIFF_TSPEC) 1226 rn = convert(NOOP, 0, gettyp(PTRDIFF_TSPEC), rn); 1227 tp = ln->tn_type; 1228 } else if (rt == PTR && is_integer(lt)) { 1229 if (lt != PTRDIFF_TSPEC) 1230 ln = convert(NOOP, 0, gettyp(PTRDIFF_TSPEC), ln); 1231 tp = rn->tn_type; 1232 } else if (lt == PTR && is_null_pointer(rn)) { 1233 tp = merge_qualifiers(ln->tn_type, rn->tn_type); 1234 } else if (rt == PTR && is_null_pointer(ln)) { 1235 tp = merge_qualifiers(rn->tn_type, ln->tn_type); 1236 } else if (lt == PTR && ln->tn_type->t_subt->t_tspec == VOID) { 1237 tp = merge_qualifiers(ln->tn_type, rn->tn_type); 1238 } else if (rt == PTR && rn->tn_type->t_subt->t_tspec == VOID) { 1239 tp = merge_qualifiers(rn->tn_type, ln->tn_type); 1240 } else { 1241 /* 1242 * XXX For now we simply take the left type. This is 1243 * probably wrong, if one type contains a function prototype 1244 * and the other one, at the same place, only an old-style 1245 * declaration. 1246 */ 1247 tp = merge_qualifiers(ln->tn_type, rn->tn_type); 1248 } 1249 1250 return new_tnode(COLON, sys, tp, ln, rn); 1251 } 1252 1253 /* TODO: check for varargs */ 1254 static bool 1255 is_cast_redundant(const tnode_t *tn) 1256 { 1257 const type_t *ntp = tn->tn_type, *otp = tn->tn_left->tn_type; 1258 tspec_t nt = ntp->t_tspec, ot = otp->t_tspec; 1259 1260 if (nt == BOOL || ot == BOOL) 1261 return nt == BOOL && ot == BOOL; 1262 1263 if (is_integer(nt) && is_integer(ot)) { 1264 unsigned int nw = width_in_bits(ntp), ow = width_in_bits(otp); 1265 if (is_uinteger(nt) == is_uinteger(ot)) 1266 return nw >= ow; 1267 return is_uinteger(ot) && nw > ow; 1268 } 1269 1270 if (is_complex(nt) || is_complex(ot)) 1271 return is_complex(nt) && is_complex(ot) && 1272 size_in_bits(nt) >= size_in_bits(ot); 1273 1274 if (is_floating(nt) && is_floating(ot)) 1275 return size_in_bits(nt) >= size_in_bits(ot); 1276 1277 if (nt == PTR && ot == PTR) { 1278 if (!ntp->t_subt->t_const && otp->t_subt->t_const) 1279 return false; 1280 if (!ntp->t_subt->t_volatile && otp->t_subt->t_volatile) 1281 return false; 1282 1283 if (ntp->t_subt->t_tspec == VOID || 1284 otp->t_subt->t_tspec == VOID || 1285 types_compatible(ntp->t_subt, otp->t_subt, 1286 false, false, NULL)) 1287 return true; 1288 } 1289 1290 return false; 1291 } 1292 1293 static bool 1294 is_assignment(op_t op) 1295 { 1296 1297 return op == ASSIGN || 1298 op == MULASS || 1299 op == DIVASS || 1300 op == MODASS || 1301 op == ADDASS || 1302 op == SUBASS || 1303 op == SHLASS || 1304 op == SHRASS || 1305 op == ANDASS || 1306 op == XORASS || 1307 op == ORASS || 1308 op == RETURN || 1309 op == INIT; 1310 } 1311 1312 /* Create a node for an assignment operator (both '=' and 'op='). */ 1313 static tnode_t * 1314 build_assignment(op_t op, bool sys, tnode_t *ln, tnode_t *rn) 1315 { 1316 1317 tspec_t lt = ln->tn_type->t_tspec; 1318 tspec_t rt = rn->tn_type->t_tspec; 1319 1320 if (any_query_enabled && is_assignment(rn->tn_op)) { 1321 /* chained assignment with '%s' and '%s' */ 1322 query_message(10, op_name(op), op_name(rn->tn_op)); 1323 } 1324 1325 if ((op == ADDASS || op == SUBASS) && lt == PTR) { 1326 lint_assert(is_integer(rt)); 1327 tnode_t *ctn = subt_size_in_bytes(ln->tn_type); 1328 if (rn->tn_type->t_tspec != ctn->tn_type->t_tspec) 1329 rn = convert(NOOP, 0, ctn->tn_type, rn); 1330 rn = new_tnode(MULT, sys, rn->tn_type, rn, ctn); 1331 if (rn->tn_left->tn_op == CON) 1332 rn = fold(rn); 1333 } 1334 1335 if ((op == ASSIGN || op == RETURN || op == INIT) && 1336 (lt == STRUCT || rt == STRUCT)) { 1337 lint_assert(lt == rt); 1338 lint_assert(ln->tn_type->t_sou == rn->tn_type->t_sou); 1339 if (is_incomplete(ln->tn_type)) { 1340 if (op == RETURN) { 1341 /* cannot return incomplete type */ 1342 error(212); 1343 } else { 1344 /* unknown operand size, op '%s' */ 1345 error(138, op_name(op)); 1346 } 1347 return NULL; 1348 } 1349 } 1350 1351 if (op == SHLASS) { 1352 if (portable_size_in_bits(lt) < portable_size_in_bits(rt)) { 1353 if (hflag) 1354 /* semantics of '%s' change in ANSI C; ... */ 1355 warning(118, "<<="); 1356 } 1357 } else if (op != SHRASS) { 1358 if (op == ASSIGN || lt != PTR) { 1359 if (lt != rt || 1360 (ln->tn_type->t_bitfield && rn->tn_op == CON)) { 1361 rn = convert(op, 0, ln->tn_type, rn); 1362 rt = lt; 1363 } 1364 } 1365 } 1366 1367 if (any_query_enabled && rn->tn_op == CVT && rn->tn_cast && 1368 types_compatible(ln->tn_type, rn->tn_type, false, false, NULL) && 1369 is_cast_redundant(rn)) { 1370 /* redundant cast from '%s' to '%s' before assignment */ 1371 query_message(7, 1372 type_name(rn->tn_left->tn_type), type_name(rn->tn_type)); 1373 } 1374 1375 return new_tnode(op, sys, ln->tn_type, ln, rn); 1376 } 1377 1378 /* 1379 * Create a node for REAL, IMAG 1380 */ 1381 static tnode_t * 1382 build_real_imag(op_t op, bool sys, tnode_t *ln) 1383 { 1384 1385 lint_assert(ln != NULL); 1386 if (ln->tn_op == NAME) { 1387 /* 1388 * This may be too much, but it avoids wrong warnings. 1389 * See d_c99_complex_split.c. 1390 */ 1391 mark_as_used(ln->tn_sym, false, false); 1392 mark_as_set(ln->tn_sym); 1393 } 1394 1395 tnode_t *cn; 1396 switch (ln->tn_type->t_tspec) { 1397 case LCOMPLEX: 1398 /* XXX: integer and LDOUBLE don't match. */ 1399 cn = build_integer_constant(LDOUBLE, (int64_t)1); 1400 break; 1401 case DCOMPLEX: 1402 /* XXX: integer and DOUBLE don't match. */ 1403 cn = build_integer_constant(DOUBLE, (int64_t)1); 1404 break; 1405 case FCOMPLEX: 1406 /* XXX: integer and FLOAT don't match. */ 1407 cn = build_integer_constant(FLOAT, (int64_t)1); 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 = new_tnode(op, sys, cn->tn_type, ln, cn); 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 bool l = constant_is_nonzero(tn->tn_left); 1500 bool r = is_binary(tn) && constant_is_nonzero(tn->tn_right); 1501 1502 switch (tn->tn_op) { 1503 case NOT: 1504 if (hflag && !constcond_flag) 1505 /* constant argument to '!' */ 1506 warning(239); 1507 v->u.integer = !l ? 1 : 0; 1508 break; 1509 case LOGAND: 1510 v->u.integer = l && r ? 1 : 0; 1511 break; 1512 case LOGOR: 1513 v->u.integer = l || r ? 1 : 0; 1514 break; 1515 default: 1516 lint_assert(/*CONSTCOND*/false); 1517 } 1518 1519 return build_constant(tn->tn_type, v); 1520 } 1521 1522 static long double 1523 floating_error_value(tspec_t t, long double lv) 1524 { 1525 if (t == FLOAT) 1526 return lv < 0 ? -FLT_MAX : FLT_MAX; 1527 if (t == DOUBLE) 1528 return lv < 0 ? -DBL_MAX : DBL_MAX; 1529 /* 1530 * When NetBSD is cross-built in MKLINT=yes mode on x86_64 for 1531 * sparc64, tools/lint checks this code while building usr.bin/xlint. 1532 * In that situation, lint uses the preprocessor for sparc64, in which 1533 * the type 'long double' is IEEE-754-binary128, affecting the macro 1534 * LDBL_MAX below. The type 'long double', as well as the strtold 1535 * implementation, comes from the host platform x86_64 though, where 1536 * 'long double' consumes 128 bits as well but only uses 80 of them. 1537 * The exponent range of the two 'long double' types is the same, but 1538 * the maximum finite value differs due to the extended precision on 1539 * sparc64. 1540 * 1541 * To properly handle the data types of the target platform, lint 1542 * would have to implement the floating-point types in a 1543 * platform-independent way, which is not worth the effort, given how 1544 * few programs practically use 'long double'. 1545 */ 1546 /* LINTED 248: floating-point constant out of range */ 1547 long double max = LDBL_MAX; 1548 return lv < 0 ? -max : max; 1549 } 1550 1551 static bool 1552 is_floating_overflow(tspec_t t, long double val) 1553 { 1554 if (fpe != 0 || isfinite(val) == 0) 1555 return true; 1556 if (t == FLOAT && (val > FLT_MAX || val < -FLT_MAX)) 1557 return true; 1558 if (t == DOUBLE && (val > DBL_MAX || val < -DBL_MAX)) 1559 return true; 1560 return false; 1561 } 1562 1563 /* 1564 * Fold constant nodes having operands with floating point type. 1565 */ 1566 static tnode_t * 1567 fold_float(tnode_t *tn) 1568 { 1569 1570 fpe = 0; 1571 1572 tspec_t t = tn->tn_type->t_tspec; 1573 1574 val_t *v = xcalloc(1, sizeof(*v)); 1575 v->v_tspec = t; 1576 1577 lint_assert(is_floating(t)); 1578 lint_assert(t == tn->tn_left->tn_type->t_tspec); 1579 lint_assert(!is_binary(tn) || t == tn->tn_right->tn_type->t_tspec); 1580 1581 long double lv = tn->tn_left->tn_val.u.floating; 1582 long double rv = is_binary(tn) ? tn->tn_right->tn_val.u.floating : 0.0; 1583 1584 switch (tn->tn_op) { 1585 case UPLUS: 1586 v->u.floating = lv; 1587 break; 1588 case UMINUS: 1589 v->u.floating = -lv; 1590 break; 1591 case MULT: 1592 v->u.floating = lv * rv; 1593 break; 1594 case DIV: 1595 if (rv == 0.0) { 1596 /* division by 0 */ 1597 error(139); 1598 v->u.floating = floating_error_value(t, lv); 1599 } else { 1600 v->u.floating = lv / rv; 1601 } 1602 break; 1603 case PLUS: 1604 v->u.floating = lv + rv; 1605 break; 1606 case MINUS: 1607 v->u.floating = lv - rv; 1608 break; 1609 case LT: 1610 v->u.integer = lv < rv ? 1 : 0; 1611 break; 1612 case LE: 1613 v->u.integer = lv <= rv ? 1 : 0; 1614 break; 1615 case GE: 1616 v->u.integer = lv >= rv ? 1 : 0; 1617 break; 1618 case GT: 1619 v->u.integer = lv > rv ? 1 : 0; 1620 break; 1621 case EQ: 1622 v->u.integer = lv == rv ? 1 : 0; 1623 break; 1624 case NE: 1625 v->u.integer = lv != rv ? 1 : 0; 1626 break; 1627 default: 1628 lint_assert(/*CONSTCOND*/false); 1629 } 1630 1631 lint_assert(fpe != 0 || isnan(v->u.floating) == 0); 1632 if (is_complex(v->v_tspec)) { 1633 /* 1634 * Don't warn, as lint doesn't model the imaginary part of 1635 * complex numbers. 1636 */ 1637 fpe = 0; 1638 } else if (is_floating_overflow(t, v->u.floating)) { 1639 /* floating point overflow on operator '%s' */ 1640 warning(142, op_name(tn->tn_op)); 1641 v->u.floating = floating_error_value(t, v->u.floating); 1642 fpe = 0; 1643 } 1644 1645 return build_constant(tn->tn_type, v); 1646 } 1647 1648 /* 1649 * Create a tree node for a binary operator and its two operands. Also called 1650 * for unary operators; in that case rn is NULL. 1651 * 1652 * Function calls, sizeof and casts are handled elsewhere. 1653 */ 1654 tnode_t * 1655 build_binary(tnode_t *ln, op_t op, bool sys, tnode_t *rn) 1656 { 1657 const mod_t *mp = &modtab[op]; 1658 1659 /* If there was an error in one of the operands, return. */ 1660 if (ln == NULL || (mp->m_binary && rn == NULL)) 1661 return NULL; 1662 1663 /* 1664 * Apply class conversions to the left operand, but only if its 1665 * value is needed or compared with zero. 1666 */ 1667 if (mp->m_value_context || mp->m_compares_with_zero) 1668 ln = cconv(ln); 1669 /* 1670 * The right operand is almost always in a test or value context, 1671 * except if it is a struct or union member. 1672 */ 1673 if (mp->m_binary && op != ARROW && op != POINT) 1674 rn = cconv(rn); 1675 1676 /* 1677 * Print some warnings for comparisons of unsigned values with 1678 * constants lower than or equal to null. This must be done 1679 * before promote() because otherwise unsigned char and unsigned 1680 * short would be promoted to int. Types are also tested to be 1681 * CHAR, which would also become int. 1682 */ 1683 if (mp->m_comparison) 1684 check_integer_comparison(op, ln, rn); 1685 1686 if (mp->m_value_context || mp->m_compares_with_zero) 1687 ln = promote(op, false, ln); 1688 if (mp->m_binary && op != ARROW && op != POINT && 1689 op != ASSIGN && op != RETURN && op != INIT) { 1690 rn = promote(op, false, rn); 1691 } 1692 1693 /* 1694 * If the result of the operation is different for signed or 1695 * unsigned operands and one of the operands is signed only in 1696 * ANSI C, print a warning. 1697 */ 1698 if (mp->m_warn_if_left_unsigned_in_c90 && 1699 ln->tn_op == CON && ln->tn_val.v_unsigned_since_c90) { 1700 /* ANSI C treats constant as unsigned, op '%s' */ 1701 warning(218, mp->m_name); 1702 ln->tn_val.v_unsigned_since_c90 = false; 1703 } 1704 if (mp->m_warn_if_right_unsigned_in_c90 && 1705 rn->tn_op == CON && rn->tn_val.v_unsigned_since_c90) { 1706 /* ANSI C treats constant as unsigned, op '%s' */ 1707 warning(218, mp->m_name); 1708 rn->tn_val.v_unsigned_since_c90 = false; 1709 } 1710 1711 /* Make sure both operands are of the same type */ 1712 if (mp->m_balance_operands || (!allow_c90 && (op == SHL || op == SHR))) 1713 balance(op, &ln, &rn); 1714 1715 /* 1716 * Check types for compatibility with the operation and mutual 1717 * compatibility. Return if there are serious problems. 1718 */ 1719 if (!typeok(op, 0, ln, rn)) 1720 return NULL; 1721 1722 /* And now create the node. */ 1723 tnode_t *ntn; 1724 switch (op) { 1725 case POINT: 1726 case ARROW: 1727 ntn = build_struct_access(op, sys, ln, rn); 1728 break; 1729 case INCAFT: 1730 case DECAFT: 1731 case INCBEF: 1732 case DECBEF: 1733 ntn = build_prepost_incdec(op, sys, ln); 1734 break; 1735 case ADDR: 1736 ntn = build_address(sys, ln, false); 1737 break; 1738 case INDIR: 1739 ntn = new_tnode(INDIR, sys, ln->tn_type->t_subt, ln, NULL); 1740 break; 1741 case PLUS: 1742 case MINUS: 1743 ntn = build_plus_minus(op, sys, ln, rn); 1744 break; 1745 case SHL: 1746 case SHR: 1747 ntn = build_bit_shift(op, sys, ln, rn); 1748 break; 1749 case COLON: 1750 ntn = build_colon(sys, ln, rn); 1751 break; 1752 case ASSIGN: 1753 case MULASS: 1754 case DIVASS: 1755 case MODASS: 1756 case ADDASS: 1757 case SUBASS: 1758 case SHLASS: 1759 case SHRASS: 1760 case ANDASS: 1761 case XORASS: 1762 case ORASS: 1763 case RETURN: 1764 case INIT: 1765 ntn = build_assignment(op, sys, ln, rn); 1766 break; 1767 case COMMA: 1768 if (any_query_enabled) { 1769 /* comma operator with types '%s' and '%s' */ 1770 query_message(12, 1771 type_name(ln->tn_type), type_name(rn->tn_type)); 1772 } 1773 /* FALLTHROUGH */ 1774 case QUEST: 1775 ntn = new_tnode(op, sys, rn->tn_type, ln, rn); 1776 break; 1777 case REAL: 1778 case IMAG: 1779 ntn = build_real_imag(op, sys, ln); 1780 break; 1781 default: 1782 lint_assert(mp->m_binary == (rn != NULL)); 1783 type_t *rettp = mp->m_returns_bool 1784 ? gettyp(Tflag ? BOOL : INT) : ln->tn_type; 1785 ntn = new_tnode(op, sys, rettp, ln, rn); 1786 break; 1787 } 1788 1789 /* Return if an error occurred. */ 1790 if (ntn == NULL) 1791 return NULL; 1792 1793 /* Print a warning if precedence confusion is possible */ 1794 if (mp->m_possible_precedence_confusion) 1795 check_precedence_confusion(ntn); 1796 1797 /* 1798 * Print a warning if one of the operands is in a context where 1799 * it is compared with zero and if this operand is a constant. 1800 */ 1801 if (hflag && !constcond_flag && 1802 mp->m_compares_with_zero && 1803 (ln->tn_op == CON || 1804 ((mp->m_binary && op != QUEST) && rn->tn_op == CON)) && 1805 /* XXX: rn->tn_system_dependent should be checked as well */ 1806 !ln->tn_system_dependent) { 1807 /* constant in conditional context */ 1808 warning(161); 1809 } 1810 1811 /* Fold if the operator requires it */ 1812 if (mp->m_fold_constant_operands) { 1813 if (ln->tn_op == CON && (!mp->m_binary || rn->tn_op == CON)) { 1814 if (mp->m_compares_with_zero) { 1815 ntn = fold_bool(ntn); 1816 } else if (is_floating(ntn->tn_type->t_tspec)) { 1817 ntn = fold_float(ntn); 1818 } else { 1819 ntn = fold(ntn); 1820 } 1821 } else if (op == QUEST && ln->tn_op == CON) { 1822 ntn = ln->tn_val.u.integer != 0 1823 ? rn->tn_left : rn->tn_right; 1824 } 1825 } 1826 1827 return ntn; 1828 } 1829 1830 tnode_t * 1831 build_unary(op_t op, bool sys, tnode_t *tn) 1832 { 1833 return build_binary(tn, op, sys, NULL); 1834 } 1835 1836 static bool 1837 are_members_compatible(const sym_t *a, const sym_t *b) 1838 { 1839 if (a->u.s_member.sm_offset_in_bits != b->u.s_member.sm_offset_in_bits) 1840 return false; 1841 1842 const type_t *atp = a->s_type; 1843 const type_t *btp = b->s_type; 1844 bool w = false; 1845 if (!types_compatible(atp, btp, false, false, &w) && !w) 1846 return false; 1847 if (a->s_bitfield != b->s_bitfield) 1848 return false; 1849 if (a->s_bitfield) { 1850 if (atp->t_bit_field_width != btp->t_bit_field_width) 1851 return false; 1852 if (atp->t_bit_field_offset != btp->t_bit_field_offset) 1853 return false; 1854 } 1855 return true; 1856 } 1857 1858 /* 1859 * Return whether all struct/union members with the same name have the same 1860 * type and offset. 1861 */ 1862 static bool 1863 all_members_compatible(const sym_t *msym) 1864 { 1865 for (const sym_t *csym = msym; 1866 csym != NULL; csym = csym->s_symtab_next) { 1867 if (!is_member(csym)) 1868 continue; 1869 if (strcmp(msym->s_name, csym->s_name) != 0) 1870 continue; 1871 1872 for (const sym_t *sym = csym->s_symtab_next; 1873 sym != NULL; sym = sym->s_symtab_next) { 1874 if (is_member(sym) 1875 && strcmp(csym->s_name, sym->s_name) == 0 1876 && !are_members_compatible(csym, sym)) 1877 return false; 1878 } 1879 } 1880 return true; 1881 } 1882 1883 sym_t * 1884 find_member(const type_t *tp, const char *name) 1885 { 1886 for (sym_t *mem = tp->t_sou->sou_first_member; 1887 mem != NULL; mem = mem->s_next) { 1888 if (strcmp(mem->s_name, name) == 0) 1889 return mem; 1890 } 1891 for (sym_t *mem = tp->t_sou->sou_first_member; 1892 mem != NULL; mem = mem->s_next) { 1893 if (is_struct_or_union(mem->s_type->t_tspec) && 1894 mem->s_name == unnamed) { 1895 sym_t *nested_mem = find_member(mem->s_type, name); 1896 if (nested_mem != NULL) 1897 return nested_mem; 1898 } 1899 } 1900 return NULL; 1901 } 1902 1903 /* 1904 * Returns a symbol which has the same name as the msym argument and is a 1905 * member of the struct or union specified by the tn argument. 1906 */ 1907 static sym_t * 1908 struct_or_union_member(tnode_t *tn, op_t op, sym_t *msym) 1909 { 1910 1911 /* 1912 * Remove the member if it was unknown until now, which means 1913 * that no defined struct or union has a member with the same name. 1914 */ 1915 if (msym->s_scl == NOSCL) { 1916 /* type '%s' does not have member '%s' */ 1917 error(101, type_name(tn->tn_type), msym->s_name); 1918 rmsym(msym); 1919 msym->s_kind = FMEMBER; 1920 msym->s_scl = STRUCT_MEMBER; 1921 1922 struct_or_union *sou = expr_zero_alloc(sizeof(*sou)); 1923 sou->sou_tag = expr_zero_alloc(sizeof(*sou->sou_tag)); 1924 sou->sou_tag->s_name = unnamed; 1925 1926 msym->u.s_member.sm_containing_type = sou; 1927 /* 1928 * The member sm_offset_in_bits is not needed here since this 1929 * symbol can only be used for error reporting. 1930 */ 1931 return msym; 1932 } 1933 1934 /* Determine the tag type of which msym is expected to be a member. */ 1935 const type_t *tp = NULL; 1936 if (op == POINT && is_struct_or_union(tn->tn_type->t_tspec)) 1937 tp = tn->tn_type; 1938 if (op == ARROW && tn->tn_type->t_tspec == PTR 1939 && is_struct_or_union(tn->tn_type->t_subt->t_tspec)) 1940 tp = tn->tn_type->t_subt; 1941 struct_or_union *sou = tp != NULL ? tp->t_sou : NULL; 1942 1943 /* 1944 * If this struct/union has a member with the name of msym, return it. 1945 */ 1946 if (sou != NULL) { 1947 for (sym_t *sym = msym; 1948 sym != NULL; sym = sym->s_symtab_next) { 1949 if (is_member(sym) && 1950 sym->u.s_member.sm_containing_type == sou && 1951 strcmp(sym->s_name, msym->s_name) == 0) 1952 return sym; 1953 } 1954 } 1955 1956 if (tp != NULL) { 1957 sym_t *nested_mem = find_member(tp, msym->s_name); 1958 if (nested_mem != NULL) 1959 return nested_mem; 1960 } 1961 1962 bool eq = all_members_compatible(msym); 1963 1964 /* 1965 * Now handle the case in which the left operand refers really 1966 * to a struct/union, but the right operand is not member of it. 1967 */ 1968 if (sou != NULL) { 1969 if (eq && !allow_c90) { 1970 /* illegal use of member '%s' */ 1971 warning(102, msym->s_name); 1972 } else { 1973 /* illegal use of member '%s' */ 1974 error(102, msym->s_name); 1975 } 1976 return msym; 1977 } 1978 1979 /* 1980 * Now the left operand of ARROW does not point to a struct/union 1981 * or the left operand of POINT is no struct/union. 1982 */ 1983 if (eq) { 1984 if (op == POINT) { 1985 if (!allow_c90) { 1986 /* left operand of '.' must be struct ... */ 1987 warning(103, type_name(tn->tn_type)); 1988 } else { 1989 /* left operand of '.' must be struct ... */ 1990 error(103, type_name(tn->tn_type)); 1991 } 1992 } else { 1993 if (!allow_c90 && tn->tn_type->t_tspec == PTR) { 1994 /* left operand of '->' must be pointer ... */ 1995 warning(104, type_name(tn->tn_type)); 1996 } else { 1997 /* left operand of '->' must be pointer ... */ 1998 error(104, type_name(tn->tn_type)); 1999 } 2000 } 2001 } else { 2002 if (!allow_c90) { 2003 /* non-unique member requires struct/union %s */ 2004 error(105, op == POINT ? "object" : "pointer"); 2005 } else { 2006 /* unacceptable operand of '%s' */ 2007 error(111, op_name(op)); 2008 } 2009 } 2010 2011 return msym; 2012 } 2013 2014 tnode_t * 2015 build_member_access(tnode_t *ln, op_t op, bool sys, sbuf_t *member) 2016 { 2017 sym_t *msym; 2018 2019 if (ln == NULL) 2020 return NULL; 2021 2022 if (op == ARROW) { 2023 /* must do this before struct_or_union_member is called */ 2024 ln = cconv(ln); 2025 } 2026 msym = struct_or_union_member(ln, op, getsym(member)); 2027 return build_binary(ln, op, sys, build_name(msym, false)); 2028 } 2029 2030 /* 2031 * Perform class conversions. 2032 * 2033 * Arrays of type T are converted into pointers to type T. 2034 * Functions are converted to pointers to functions. 2035 * Lvalues are converted to rvalues. 2036 * 2037 * C99 6.3 "Conversions" 2038 * C99 6.3.2 "Other operands" 2039 * C99 6.3.2.1 "Lvalues, arrays, and function designators" 2040 */ 2041 tnode_t * 2042 cconv(tnode_t *tn) 2043 { 2044 /* 2045 * Array-lvalue (array of type T) is converted into rvalue 2046 * (pointer to type T) 2047 */ 2048 if (tn->tn_type->t_tspec == ARRAY) { 2049 if (!tn->tn_lvalue) { 2050 /* XXX print correct operator */ 2051 /* %soperand of '%s' must be lvalue */ 2052 gnuism(114, "", op_name(ADDR)); 2053 } 2054 tn = new_tnode(ADDR, tn->tn_sys, 2055 expr_derive_type(tn->tn_type->t_subt, PTR), tn, NULL); 2056 } 2057 2058 /* 2059 * Expression of type function (function with return value of type T) 2060 * in rvalue-expression (pointer to function with return value 2061 * of type T) 2062 */ 2063 if (tn->tn_type->t_tspec == FUNC) 2064 tn = build_address(tn->tn_sys, tn, true); 2065 2066 /* lvalue to rvalue */ 2067 if (tn->tn_lvalue) { 2068 type_t *tp = expr_dup_type(tn->tn_type); 2069 /* C99 6.3.2.1p2 sentence 2 says to remove the qualifiers. */ 2070 tp->t_const = tp->t_volatile = false; 2071 tn = new_tnode(LOAD, tn->tn_sys, tp, tn, NULL); 2072 } 2073 2074 return tn; 2075 } 2076 2077 const tnode_t * 2078 before_conversion(const tnode_t *tn) 2079 { 2080 while (tn->tn_op == CVT && !tn->tn_cast) 2081 tn = tn->tn_left; 2082 return tn; 2083 } 2084 2085 /* 2086 * Most errors required by ANSI C are reported in struct_or_union_member(). 2087 * Here we only check for totally wrong things. 2088 */ 2089 static bool 2090 typeok_point(const tnode_t *ln, const type_t *ltp, tspec_t lt) 2091 { 2092 if (is_struct_or_union(lt)) 2093 return true; 2094 2095 if (lt == FUNC || lt == VOID || ltp->t_bitfield) 2096 goto wrong; 2097 2098 /* 2099 * Some C dialects from before C90 tolerated any lvalue on the 2100 * left-hand side of the '.' operator, allowing things like 2101 * char st[100]; st.st_mtime, assuming that the member 'st_mtime' 2102 * only occurred in a single struct; see typeok_arrow. 2103 */ 2104 if (ln->tn_lvalue) 2105 return true; 2106 2107 wrong: 2108 /* With allow_c90 we already got an error */ 2109 if (!allow_c90) 2110 /* unacceptable operand of '%s' */ 2111 error(111, op_name(POINT)); 2112 2113 return false; 2114 } 2115 2116 static bool 2117 typeok_arrow(tspec_t lt) 2118 { 2119 /* 2120 * C1978 Appendix A 14.1 says: <quote>In fact, any lvalue is allowed 2121 * before '.', and that lvalue is then assumed to have the form of 2122 * the structure of which the name of the right is a member. [...] 2123 * Such constructions are non-portable.</quote> 2124 */ 2125 if (lt == PTR || (!allow_c90 && is_integer(lt))) 2126 return true; 2127 2128 /* With allow_c90 we already got an error */ 2129 if (!allow_c90) 2130 /* unacceptable operand of '%s' */ 2131 error(111, op_name(ARROW)); 2132 return false; 2133 } 2134 2135 static bool 2136 typeok_incdec(op_t op, const tnode_t *tn, const type_t *tp) 2137 { 2138 /* operand has scalar type (checked in typeok) */ 2139 if (!tn->tn_lvalue) { 2140 if (tn->tn_op == CVT && tn->tn_cast && 2141 tn->tn_left->tn_op == LOAD) { 2142 /* a cast does not yield an lvalue */ 2143 error(163); 2144 } 2145 /* %soperand of '%s' must be lvalue */ 2146 error(114, "", op_name(op)); 2147 return false; 2148 } 2149 if (tp->t_const && allow_c90) { 2150 /* %soperand of '%s' must be modifiable lvalue */ 2151 warning(115, "", op_name(op)); 2152 } 2153 return true; 2154 } 2155 2156 static bool 2157 typeok_address(const mod_t *mp, 2158 const tnode_t *tn, const type_t *tp, tspec_t t) 2159 { 2160 if (t == ARRAY || t == FUNC) { 2161 /* ok, a warning comes later (in build_address()) */ 2162 } else if (!tn->tn_lvalue) { 2163 if (tn->tn_op == CVT && tn->tn_cast && 2164 tn->tn_left->tn_op == LOAD) { 2165 /* a cast does not yield an lvalue */ 2166 error(163); 2167 } 2168 /* %soperand of '%s' must be lvalue */ 2169 error(114, "", mp->m_name); 2170 return false; 2171 } else if (is_scalar(t)) { 2172 if (tp->t_bitfield) { 2173 /* cannot take address of bit-field */ 2174 error(112); 2175 return false; 2176 } 2177 } else if (t != STRUCT && t != UNION) { 2178 /* unacceptable operand of '%s' */ 2179 error(111, mp->m_name); 2180 return false; 2181 } 2182 if (tn->tn_op == NAME && tn->tn_sym->s_register) { 2183 /* cannot take address of register '%s' */ 2184 error(113, tn->tn_sym->s_name); 2185 return false; 2186 } 2187 return true; 2188 } 2189 2190 static bool 2191 typeok_indir(const type_t *tp, tspec_t t) 2192 { 2193 2194 if (t != PTR) { 2195 /* cannot dereference non-pointer type '%s' */ 2196 error(96, type_name(tp)); 2197 return false; 2198 } 2199 return true; 2200 } 2201 2202 static void 2203 warn_incompatible_types(op_t op, 2204 const type_t *ltp, tspec_t lt, 2205 const type_t *rtp, tspec_t rt) 2206 { 2207 const mod_t *mp = &modtab[op]; 2208 2209 if (lt == VOID || (mp->m_binary && rt == VOID)) { 2210 /* void type illegal in expression */ 2211 error(109); 2212 } else if (op == ASSIGN) { 2213 /* cannot assign to '%s' from '%s' */ 2214 error(171, type_name(ltp), type_name(rtp)); 2215 } else if (mp->m_binary) { 2216 /* operands of '%s' have incompatible types '%s' and '%s' */ 2217 error(107, mp->m_name, type_name(ltp), type_name(rtp)); 2218 } else { 2219 lint_assert(rt == NO_TSPEC); 2220 /* operand of '%s' has invalid type '%s' */ 2221 error(108, mp->m_name, type_name(ltp)); 2222 } 2223 } 2224 2225 static bool 2226 typeok_plus(op_t op, 2227 const type_t *ltp, tspec_t lt, 2228 const type_t *rtp, tspec_t rt) 2229 { 2230 /* operands have scalar types (checked in typeok) */ 2231 if ((lt == PTR && !is_integer(rt)) || (rt == PTR && !is_integer(lt))) { 2232 warn_incompatible_types(op, ltp, lt, rtp, rt); 2233 return false; 2234 } 2235 return true; 2236 } 2237 2238 static bool 2239 typeok_minus(op_t op, 2240 const type_t *ltp, tspec_t lt, 2241 const type_t *rtp, tspec_t rt) 2242 { 2243 /* operands have scalar types (checked in typeok) */ 2244 if ((lt == PTR && rt != PTR && !is_integer(rt)) || 2245 (lt != PTR && rt == PTR)) { 2246 warn_incompatible_types(op, ltp, lt, rtp, rt); 2247 return false; 2248 } 2249 if (lt == PTR && rt == PTR && 2250 !types_compatible(ltp->t_subt, rtp->t_subt, true, false, NULL)) { 2251 /* illegal pointer subtraction */ 2252 error(116); 2253 } 2254 return true; 2255 } 2256 2257 static void 2258 typeok_shr(const mod_t *mp, 2259 const tnode_t *ln, tspec_t lt, 2260 const tnode_t *rn, tspec_t rt) 2261 { 2262 tspec_t olt = before_conversion(ln)->tn_type->t_tspec; 2263 tspec_t ort = before_conversion(rn)->tn_type->t_tspec; 2264 2265 /* operands have integer types (checked in typeok) */ 2266 if (pflag && !is_uinteger(olt)) { 2267 integer_constraints lc = ic_expr(ln); 2268 if (!ic_maybe_signed(ln->tn_type, &lc)) 2269 return; 2270 2271 /* 2272 * The left operand is signed. This means that 2273 * the operation is (possibly) nonportable. 2274 */ 2275 if (ln->tn_op != CON) { 2276 /* bitwise '%s' on signed value possibly nonportable */ 2277 warning(117, mp->m_name); 2278 } else if (ln->tn_val.u.integer < 0) { 2279 /* bitwise '%s' on signed value nonportable */ 2280 warning(120, mp->m_name); 2281 } 2282 } else if (allow_trad && allow_c90 && 2283 !is_uinteger(olt) && is_uinteger(ort)) { 2284 /* The left operand would become unsigned in traditional C. */ 2285 if (hflag && (ln->tn_op != CON || ln->tn_val.u.integer < 0)) { 2286 /* semantics of '%s' change in ANSI C; use ... */ 2287 warning(118, mp->m_name); 2288 } 2289 } else if (allow_trad && allow_c90 && 2290 !is_uinteger(olt) && !is_uinteger(ort) && 2291 portable_size_in_bits(lt) < portable_size_in_bits(rt)) { 2292 /* 2293 * In traditional C the left operand would be extended 2294 * (possibly sign-extended) and then shifted. 2295 */ 2296 if (hflag && (ln->tn_op != CON || ln->tn_val.u.integer < 0)) { 2297 /* semantics of '%s' change in ANSI C; use ... */ 2298 warning(118, mp->m_name); 2299 } 2300 } 2301 } 2302 2303 static void 2304 typeok_shl(const mod_t *mp, tspec_t lt, tspec_t rt) 2305 { 2306 /* 2307 * C90 does not perform balancing for shift operations, 2308 * but traditional C does. If the width of the right operand 2309 * is greater than the width of the left operand, then in 2310 * traditional C the left operand would be extended to the 2311 * width of the right operand. For SHL this may result in 2312 * different results. 2313 */ 2314 if (portable_size_in_bits(lt) < portable_size_in_bits(rt)) { 2315 /* 2316 * XXX If both operands are constant, make sure 2317 * that there is really a difference between 2318 * ANSI C and traditional C. 2319 */ 2320 if (hflag && !allow_c99) 2321 /* semantics of '%s' change in ANSI C; use ... */ 2322 warning(118, mp->m_name); 2323 } 2324 } 2325 2326 static void 2327 typeok_shift(const type_t *ltp, tspec_t lt, const tnode_t *rn, tspec_t rt) 2328 { 2329 if (rn->tn_op != CON) 2330 return; 2331 2332 if (!is_uinteger(rt) && rn->tn_val.u.integer < 0) { 2333 /* negative shift */ 2334 warning(121); 2335 } else if ((uint64_t)rn->tn_val.u.integer == size_in_bits(lt)) { 2336 /* shift amount %u equals bit-size of '%s' */ 2337 warning(267, (unsigned)rn->tn_val.u.integer, type_name(ltp)); 2338 } else if ((uint64_t)rn->tn_val.u.integer > size_in_bits(lt)) { 2339 /* shift amount %llu is greater than bit-size %llu of '%s' */ 2340 warning(122, (unsigned long long)rn->tn_val.u.integer, 2341 (unsigned long long)size_in_bits(lt), 2342 tspec_name(lt)); 2343 } 2344 } 2345 2346 static bool 2347 is_typeok_eq(const tnode_t *ln, tspec_t lt, const tnode_t *rn, tspec_t rt) 2348 { 2349 if (lt == PTR && is_null_pointer(rn)) 2350 return true; 2351 if (rt == PTR && is_null_pointer(ln)) 2352 return true; 2353 return false; 2354 } 2355 2356 /* 2357 * Called if incompatible pointer types are detected. 2358 * Print an appropriate warning. 2359 */ 2360 static void 2361 warn_incompatible_pointers(const mod_t *mp, 2362 const type_t *ltp, const type_t *rtp) 2363 { 2364 lint_assert(ltp->t_tspec == PTR); 2365 lint_assert(rtp->t_tspec == PTR); 2366 2367 tspec_t lt = ltp->t_subt->t_tspec; 2368 tspec_t rt = rtp->t_subt->t_tspec; 2369 2370 if (is_struct_or_union(lt) && is_struct_or_union(rt)) { 2371 if (mp == NULL) { 2372 /* illegal structure pointer combination */ 2373 warning(244); 2374 } else { 2375 /* incompatible structure pointers: '%s' '%s' '%s' */ 2376 warning(245, type_name(ltp), mp->m_name, type_name(rtp)); 2377 } 2378 } else { 2379 if (mp == NULL) { 2380 /* illegal combination of '%s' and '%s' */ 2381 warning(184, type_name(ltp), type_name(rtp)); 2382 } else { 2383 /* illegal combination of '%s' and '%s', op '%s' */ 2384 warning(124, 2385 type_name(ltp), type_name(rtp), mp->m_name); 2386 } 2387 } 2388 } 2389 2390 static void 2391 check_pointer_comparison(op_t op, const tnode_t *ln, const tnode_t *rn) 2392 { 2393 type_t *ltp = ln->tn_type, *rtp = rn->tn_type; 2394 tspec_t lst = ltp->t_subt->t_tspec, rst = rtp->t_subt->t_tspec; 2395 2396 if (lst == VOID || rst == VOID) { 2397 /* TODO: C99 behaves like C90 here. */ 2398 if ((!allow_trad && !allow_c99) && 2399 (lst == FUNC || rst == FUNC)) { 2400 /* (void *)0 is already handled in typeok() */ 2401 const char *lsts, *rsts; 2402 *(lst == FUNC ? &lsts : &rsts) = "function pointer"; 2403 *(lst == VOID ? &lsts : &rsts) = "'void *'"; 2404 /* ANSI C forbids comparison of %s with %s */ 2405 warning(274, lsts, rsts); 2406 } 2407 return; 2408 } 2409 2410 if (!types_compatible(ltp->t_subt, rtp->t_subt, true, false, NULL)) { 2411 warn_incompatible_pointers(&modtab[op], ltp, rtp); 2412 return; 2413 } 2414 2415 if (lst == FUNC && rst == FUNC) { 2416 /* TODO: C99 behaves like C90 here, see C99 6.5.8p2. */ 2417 if ((!allow_trad && !allow_c99) && op != EQ && op != NE) 2418 /* ANSI C forbids ordered comparisons of ... */ 2419 warning(125); 2420 } 2421 } 2422 2423 static bool 2424 typeok_compare(op_t op, 2425 const tnode_t *ln, const type_t *ltp, tspec_t lt, 2426 const tnode_t *rn, const type_t *rtp, tspec_t rt) 2427 { 2428 if (lt == PTR && rt == PTR) { 2429 check_pointer_comparison(op, ln, rn); 2430 return true; 2431 } 2432 2433 if (lt != PTR && rt != PTR) 2434 return true; 2435 2436 if (!is_integer(lt) && !is_integer(rt)) { 2437 warn_incompatible_types(op, ltp, lt, rtp, rt); 2438 return false; 2439 } 2440 2441 const char *lx = lt == PTR ? "pointer" : "integer"; 2442 const char *rx = rt == PTR ? "pointer" : "integer"; 2443 /* illegal combination of %s '%s' and %s '%s', op '%s' */ 2444 warning(123, lx, type_name(ltp), rx, type_name(rtp), op_name(op)); 2445 return true; 2446 } 2447 2448 static bool 2449 typeok_quest(tspec_t lt, const tnode_t *rn) 2450 { 2451 if (!is_scalar(lt)) { 2452 /* first operand must have scalar type, op ? : */ 2453 error(170); 2454 return false; 2455 } 2456 lint_assert(before_conversion(rn)->tn_op == COLON); 2457 return true; 2458 } 2459 2460 static void 2461 typeok_colon_pointer(const mod_t *mp, const type_t *ltp, const type_t *rtp) 2462 { 2463 type_t *lstp = ltp->t_subt; 2464 type_t *rstp = rtp->t_subt; 2465 tspec_t lst = lstp->t_tspec; 2466 tspec_t rst = rstp->t_tspec; 2467 2468 if ((lst == VOID && rst == FUNC) || (lst == FUNC && rst == VOID)) { 2469 /* (void *)0 is handled in typeok_colon */ 2470 /* TODO: C99 behaves like C90 here. */ 2471 if (!allow_trad && !allow_c99) 2472 /* ANSI C forbids conversion of %s to %s, op %s */ 2473 warning(305, "function pointer", "'void *'", 2474 mp->m_name); 2475 return; 2476 } 2477 2478 if (pointer_types_are_compatible(lstp, rstp, true)) 2479 return; 2480 if (!types_compatible(lstp, rstp, true, false, NULL)) 2481 warn_incompatible_pointers(mp, ltp, rtp); 2482 } 2483 2484 static bool 2485 typeok_colon(const mod_t *mp, 2486 const tnode_t *ln, const type_t *ltp, tspec_t lt, 2487 const tnode_t *rn, const type_t *rtp, tspec_t rt) 2488 { 2489 2490 if (is_arithmetic(lt) && is_arithmetic(rt)) 2491 return true; 2492 if (lt == BOOL && rt == BOOL) 2493 return true; 2494 2495 if (lt == STRUCT && rt == STRUCT && ltp->t_sou == rtp->t_sou) 2496 return true; 2497 if (lt == UNION && rt == UNION && ltp->t_sou == rtp->t_sou) 2498 return true; 2499 2500 if (lt == PTR && is_null_pointer(rn)) 2501 return true; 2502 if (rt == PTR && is_null_pointer(ln)) 2503 return true; 2504 2505 if ((lt == PTR && is_integer(rt)) || (is_integer(lt) && rt == PTR)) { 2506 const char *lx = lt == PTR ? "pointer" : "integer"; 2507 const char *rx = rt == PTR ? "pointer" : "integer"; 2508 /* illegal combination of %s '%s' and %s '%s', op '%s' */ 2509 warning(123, lx, type_name(ltp), 2510 rx, type_name(rtp), mp->m_name); 2511 return true; 2512 } 2513 2514 if (lt == VOID || rt == VOID) { 2515 if (lt != VOID || rt != VOID) 2516 /* incompatible types '%s' and '%s' in conditional */ 2517 warning(126, type_name(ltp), type_name(rtp)); 2518 return true; 2519 } 2520 2521 if (lt == PTR && rt == PTR) { 2522 typeok_colon_pointer(mp, ltp, rtp); 2523 return true; 2524 } 2525 2526 /* incompatible types '%s' and '%s' in conditional */ 2527 error(126, type_name(ltp), type_name(rtp)); 2528 return false; 2529 } 2530 2531 /* 2532 * Returns true if the given structure or union has a constant member 2533 * (maybe recursively). 2534 */ 2535 static bool 2536 has_constant_member(const type_t *tp) 2537 { 2538 lint_assert(is_struct_or_union(tp->t_tspec)); 2539 2540 for (sym_t *m = tp->t_sou->sou_first_member; 2541 m != NULL; m = m->s_next) { 2542 const type_t *mtp = m->s_type; 2543 if (mtp->t_const) 2544 return true; 2545 if (is_struct_or_union(mtp->t_tspec) && 2546 has_constant_member(mtp)) 2547 return true; 2548 } 2549 return false; 2550 } 2551 2552 static bool 2553 typeok_assign(op_t op, const tnode_t *ln, const type_t *ltp, tspec_t lt) 2554 { 2555 if (op == RETURN || op == INIT || op == FARG) 2556 return true; 2557 2558 if (!ln->tn_lvalue) { 2559 if (ln->tn_op == CVT && ln->tn_cast && 2560 ln->tn_left->tn_op == LOAD) { 2561 /* a cast does not yield an lvalue */ 2562 error(163); 2563 } 2564 /* %soperand of '%s' must be lvalue */ 2565 error(114, "left ", op_name(op)); 2566 return false; 2567 } else if (ltp->t_const 2568 || (is_struct_or_union(lt) && has_constant_member(ltp))) { 2569 if (allow_c90) 2570 /* %soperand of '%s' must be modifiable lvalue */ 2571 warning(115, "left ", op_name(op)); 2572 } 2573 return true; 2574 } 2575 2576 /* Check the types using the information from modtab[]. */ 2577 static bool 2578 typeok_scalar(op_t op, const mod_t *mp, 2579 const type_t *ltp, tspec_t lt, 2580 const type_t *rtp, tspec_t rt) 2581 { 2582 if (mp->m_takes_bool && lt == BOOL && rt == BOOL) 2583 return true; 2584 if (mp->m_requires_integer) { 2585 if (!is_integer(lt) || (mp->m_binary && !is_integer(rt))) { 2586 warn_incompatible_types(op, ltp, lt, rtp, rt); 2587 return false; 2588 } 2589 } else if (mp->m_requires_integer_or_complex) { 2590 if ((!is_integer(lt) && !is_complex(lt)) || 2591 (mp->m_binary && (!is_integer(rt) && !is_complex(rt)))) { 2592 warn_incompatible_types(op, ltp, lt, rtp, rt); 2593 return false; 2594 } 2595 } else if (mp->m_requires_scalar) { 2596 if (!is_scalar(lt) || (mp->m_binary && !is_scalar(rt))) { 2597 warn_incompatible_types(op, ltp, lt, rtp, rt); 2598 return false; 2599 } 2600 } else if (mp->m_requires_arith) { 2601 if (!is_arithmetic(lt) || 2602 (mp->m_binary && !is_arithmetic(rt))) { 2603 warn_incompatible_types(op, ltp, lt, rtp, rt); 2604 return false; 2605 } 2606 } 2607 return true; 2608 } 2609 2610 static void 2611 check_assign_void_pointer(op_t op, int arg, 2612 tspec_t lt, tspec_t lst, 2613 tspec_t rt, tspec_t rst) 2614 { 2615 2616 if (!(lt == PTR && rt == PTR && (lst == VOID || rst == VOID))) 2617 return; 2618 /* two pointers, at least one pointer to void */ 2619 2620 /* TODO: C99 behaves like C90 here. */ 2621 if (!((!allow_trad && !allow_c99) && (lst == FUNC || rst == FUNC))) 2622 return; 2623 /* comb. of ptr to func and ptr to void */ 2624 2625 const char *lts, *rts; 2626 *(lst == FUNC ? <s : &rts) = "function pointer"; 2627 *(lst == VOID ? <s : &rts) = "'void *'"; 2628 2629 switch (op) { 2630 case INIT: 2631 case RETURN: 2632 /* ANSI C forbids conversion of %s to %s */ 2633 warning(303, rts, lts); 2634 break; 2635 case FARG: 2636 /* ANSI C forbids conversion of %s to %s, arg #%d */ 2637 warning(304, rts, lts, arg); 2638 break; 2639 default: 2640 /* ANSI C forbids conversion of %s to %s, op %s */ 2641 warning(305, rts, lts, op_name(op)); 2642 break; 2643 } 2644 } 2645 2646 static bool 2647 is_direct_function_call(const tnode_t *tn, const char **out_name) 2648 { 2649 2650 if (!(tn->tn_op == CALL && 2651 tn->tn_left->tn_op == ADDR && 2652 tn->tn_left->tn_left->tn_op == NAME)) 2653 return false; 2654 2655 *out_name = tn->tn_left->tn_left->tn_sym->s_name; 2656 return true; 2657 } 2658 2659 static bool 2660 is_unconst_function(const char *name) 2661 { 2662 2663 return strcmp(name, "memchr") == 0 || 2664 strcmp(name, "strchr") == 0 || 2665 strcmp(name, "strpbrk") == 0 || 2666 strcmp(name, "strrchr") == 0 || 2667 strcmp(name, "strstr") == 0; 2668 } 2669 2670 static bool 2671 is_const_char_pointer(const tnode_t *tn) 2672 { 2673 /* 2674 * For traditional reasons, C99 6.4.5p5 defines that string literals 2675 * have type 'char[]'. They are often implicitly converted to 2676 * 'char *', for example when they are passed as function arguments. 2677 * 2678 * C99 6.4.5p6 further defines that modifying a string that is 2679 * constructed from a string literal invokes undefined behavior. 2680 * 2681 * Out of these reasons, string literals are treated as 'effectively 2682 * const' here. 2683 */ 2684 if (tn->tn_op == CVT && 2685 tn->tn_left->tn_op == ADDR && 2686 tn->tn_left->tn_left->tn_op == STRING) 2687 return true; 2688 2689 const type_t *tp = before_conversion(tn)->tn_type; 2690 return tp->t_tspec == PTR && 2691 tp->t_subt->t_tspec == CHAR && 2692 tp->t_subt->t_const; 2693 } 2694 2695 static bool 2696 is_first_arg_const_char_pointer(const tnode_t *tn) 2697 { 2698 const tnode_t *an = tn->tn_right; 2699 if (an == NULL) 2700 return false; 2701 2702 while (an->tn_right != NULL) 2703 an = an->tn_right; 2704 return is_const_char_pointer(an->tn_left); 2705 } 2706 2707 static bool 2708 is_const_pointer(const tnode_t *tn) 2709 { 2710 const type_t *tp = before_conversion(tn)->tn_type; 2711 return tp->t_tspec == PTR && tp->t_subt->t_const; 2712 } 2713 2714 static bool 2715 is_second_arg_const_pointer(const tnode_t *tn) 2716 { 2717 const tnode_t *an = tn->tn_right; 2718 if (an == NULL || an->tn_right == NULL) 2719 return false; 2720 2721 while (an->tn_right->tn_right != NULL) 2722 an = an->tn_right; 2723 return is_const_pointer(an->tn_left); 2724 } 2725 2726 static void 2727 check_unconst_function(const type_t *lstp, const tnode_t *rn) 2728 { 2729 const char *function_name; 2730 2731 if (lstp->t_tspec == CHAR && !lstp->t_const && 2732 is_direct_function_call(rn, &function_name) && 2733 is_unconst_function(function_name) && 2734 is_first_arg_const_char_pointer(rn)) { 2735 /* call to '%s' effectively discards 'const' from argument */ 2736 warning(346, function_name); 2737 } 2738 2739 if (!lstp->t_const && 2740 is_direct_function_call(rn, &function_name) && 2741 strcmp(function_name, "bsearch") == 0 && 2742 is_second_arg_const_pointer(rn)) { 2743 /* call to '%s' effectively discards 'const' from argument */ 2744 warning(346, function_name); 2745 } 2746 } 2747 2748 static bool 2749 check_assign_void_pointer_compat(op_t op, int arg, 2750 const type_t *const ltp, tspec_t const lt, 2751 const type_t *const lstp, tspec_t const lst, 2752 const tnode_t *const rn, 2753 const type_t *const rtp, tspec_t const rt, 2754 const type_t *const rstp, tspec_t const rst) 2755 { 2756 if (!(lt == PTR && rt == PTR && (lst == VOID || rst == VOID || 2757 types_compatible(lstp, rstp, 2758 true, false, NULL)))) 2759 return false; 2760 2761 /* compatible pointer types (qualifiers ignored) */ 2762 if (allow_c90 && 2763 ((!lstp->t_const && rstp->t_const) || 2764 (!lstp->t_volatile && rstp->t_volatile))) { 2765 /* left side has not all qualifiers of right */ 2766 switch (op) { 2767 case INIT: 2768 case RETURN: 2769 /* incompatible pointer types to '%s' and '%s' */ 2770 warning(182, type_name(lstp), type_name(rstp)); 2771 break; 2772 case FARG: 2773 /* converting '%s' to incompatible '%s' ... */ 2774 warning(153, 2775 type_name(rtp), type_name(ltp), arg); 2776 break; 2777 default: 2778 /* operands of '%s' have incompatible pointer ... */ 2779 warning(128, op_name(op), 2780 type_name(lstp), type_name(rstp)); 2781 break; 2782 } 2783 } 2784 2785 if (allow_c90) 2786 check_unconst_function(lstp, rn); 2787 2788 return true; 2789 } 2790 2791 static bool 2792 check_assign_pointer_integer(op_t op, int arg, 2793 const type_t *const ltp, tspec_t const lt, 2794 const type_t *const rtp, tspec_t const rt) 2795 { 2796 2797 if (!((lt == PTR && is_integer(rt)) || (is_integer(lt) && rt == PTR))) 2798 return false; 2799 2800 const char *lx = lt == PTR ? "pointer" : "integer"; 2801 const char *rx = rt == PTR ? "pointer" : "integer"; 2802 2803 switch (op) { 2804 case INIT: 2805 case RETURN: 2806 /* illegal combination of %s '%s' and %s '%s' */ 2807 warning(183, lx, type_name(ltp), rx, type_name(rtp)); 2808 break; 2809 case FARG: 2810 /* illegal combination of %s '%s' and %s '%s', arg #%d */ 2811 warning(154, 2812 lx, type_name(ltp), rx, type_name(rtp), arg); 2813 break; 2814 default: 2815 /* illegal combination of %s '%s' and %s '%s', op '%s' */ 2816 warning(123, 2817 lx, type_name(ltp), rx, type_name(rtp), op_name(op)); 2818 break; 2819 } 2820 return true; 2821 } 2822 2823 static bool 2824 check_assign_pointer(op_t op, int arg, 2825 const type_t *ltp, tspec_t lt, 2826 const type_t *rtp, tspec_t rt) 2827 { 2828 if (!(lt == PTR && rt == PTR)) 2829 return false; 2830 2831 switch (op) { 2832 case RETURN: 2833 warn_incompatible_pointers(NULL, ltp, rtp); 2834 break; 2835 case FARG: 2836 /* converting '%s' to incompatible '%s' for ... */ 2837 warning(153, type_name(rtp), type_name(ltp), arg); 2838 break; 2839 default: 2840 warn_incompatible_pointers(&modtab[op], ltp, rtp); 2841 break; 2842 } 2843 return true; 2844 } 2845 2846 static void 2847 warn_assign(op_t op, int arg, 2848 const type_t *ltp, tspec_t lt, 2849 const type_t *rtp, tspec_t rt) 2850 { 2851 switch (op) { 2852 case INIT: 2853 /* cannot initialize '%s' from '%s' */ 2854 error(185, type_name(ltp), type_name(rtp)); 2855 break; 2856 case RETURN: 2857 /* function has return type '%s' but returns '%s' */ 2858 error(211, type_name(ltp), type_name(rtp)); 2859 break; 2860 case FARG: 2861 /* passing '%s' to incompatible '%s', arg #%d */ 2862 warning(155, type_name(rtp), type_name(ltp), arg); 2863 break; 2864 default: 2865 warn_incompatible_types(op, ltp, lt, rtp, rt); 2866 break; 2867 } 2868 } 2869 2870 /* 2871 * Checks type compatibility for ASSIGN, INIT, FARG and RETURN 2872 * and prints warnings/errors if necessary. 2873 * Returns whether the types are (almost) compatible. 2874 */ 2875 static bool 2876 check_assign_types_compatible(op_t op, int arg, 2877 const tnode_t *ln, const tnode_t *rn) 2878 { 2879 tspec_t lt, rt, lst = NO_TSPEC, rst = NO_TSPEC; 2880 type_t *ltp, *rtp, *lstp = NULL, *rstp = NULL; 2881 2882 if ((lt = (ltp = ln->tn_type)->t_tspec) == PTR) 2883 lst = (lstp = ltp->t_subt)->t_tspec; 2884 if ((rt = (rtp = rn->tn_type)->t_tspec) == PTR) 2885 rst = (rstp = rtp->t_subt)->t_tspec; 2886 2887 if (lt == BOOL && is_scalar(rt)) /* C99 6.3.1.2 */ 2888 return true; 2889 2890 if (is_arithmetic(lt) && (is_arithmetic(rt) || rt == BOOL)) 2891 return true; 2892 2893 if (is_struct_or_union(lt) && is_struct_or_union(rt)) 2894 /* both are struct or union */ 2895 return ltp->t_sou == rtp->t_sou; 2896 2897 /* a null pointer may be assigned to any pointer */ 2898 if (lt == PTR && is_null_pointer(rn)) { 2899 if (is_integer(rn->tn_type->t_tspec)) 2900 /* implicit conversion from integer 0 to pointer ... */ 2901 query_message(15, type_name(ltp)); 2902 return true; 2903 } 2904 2905 check_assign_void_pointer(op, arg, lt, lst, rt, rst); 2906 2907 if (check_assign_void_pointer_compat(op, arg, 2908 ltp, lt, lstp, lst, rn, rtp, rt, rstp, rst)) 2909 return true; 2910 2911 if (check_assign_pointer_integer(op, arg, ltp, lt, rtp, rt)) 2912 return true; 2913 2914 if (check_assign_pointer(op, arg, ltp, lt, rtp, rt)) 2915 return true; 2916 2917 warn_assign(op, arg, ltp, lt, rtp, rt); 2918 return false; 2919 } 2920 2921 static bool 2922 has_side_effect(const tnode_t *tn) /* NOLINT(misc-no-recursion) */ 2923 { 2924 op_t op = tn->tn_op; 2925 2926 if (modtab[op].m_has_side_effect) 2927 return true; 2928 2929 if (op == CVT && tn->tn_type->t_tspec == VOID) 2930 return has_side_effect(tn->tn_left); 2931 2932 /* XXX: Why not has_side_effect(tn->tn_left) as well? */ 2933 if (op == LOGAND || op == LOGOR) 2934 return has_side_effect(tn->tn_right); 2935 2936 /* XXX: Why not has_side_effect(tn->tn_left) as well? */ 2937 if (op == QUEST) 2938 return has_side_effect(tn->tn_right); 2939 2940 if (op == COLON || op == COMMA) { 2941 return has_side_effect(tn->tn_left) || 2942 has_side_effect(tn->tn_right); 2943 } 2944 2945 return false; 2946 } 2947 2948 static bool 2949 is_void_cast(const tnode_t *tn) 2950 { 2951 2952 return tn->tn_op == CVT && tn->tn_cast && 2953 tn->tn_type->t_tspec == VOID; 2954 } 2955 2956 static bool 2957 is_local_symbol(const tnode_t *tn) 2958 { 2959 2960 return tn->tn_op == LOAD && 2961 tn->tn_left->tn_op == NAME && 2962 tn->tn_left->tn_sym->s_scl == AUTO; 2963 } 2964 2965 static bool 2966 is_int_constant_zero(const tnode_t *tn) 2967 { 2968 2969 return tn->tn_op == CON && 2970 tn->tn_type->t_tspec == INT && 2971 tn->tn_val.u.integer == 0; 2972 } 2973 2974 static void 2975 check_null_effect(const tnode_t *tn) 2976 { 2977 2978 if (hflag && 2979 !has_side_effect(tn) && 2980 !(is_void_cast(tn) && is_local_symbol(tn->tn_left)) && 2981 !(is_void_cast(tn) && is_int_constant_zero(tn->tn_left))) { 2982 /* expression has null effect */ 2983 warning(129); 2984 } 2985 } 2986 2987 /* 2988 * Check the types for specific operators and type combinations. 2989 * 2990 * At this point, the operands already conform to the type requirements of 2991 * the operator, such as being integer, floating or scalar. 2992 */ 2993 static bool 2994 typeok_op(op_t op, const mod_t *mp, int arg, 2995 const tnode_t *ln, const type_t *ltp, tspec_t lt, 2996 const tnode_t *rn, const type_t *rtp, tspec_t rt) 2997 { 2998 switch (op) { 2999 case ARROW: 3000 return typeok_arrow(lt); 3001 case POINT: 3002 return typeok_point(ln, ltp, lt); 3003 case INCBEF: 3004 case DECBEF: 3005 case INCAFT: 3006 case DECAFT: 3007 return typeok_incdec(op, ln, ltp); 3008 case INDIR: 3009 return typeok_indir(ltp, lt); 3010 case ADDR: 3011 return typeok_address(mp, ln, ltp, lt); 3012 case PLUS: 3013 return typeok_plus(op, ltp, lt, rtp, rt); 3014 case MINUS: 3015 return typeok_minus(op, ltp, lt, rtp, rt); 3016 case SHL: 3017 typeok_shl(mp, lt, rt); 3018 goto shift; 3019 case SHR: 3020 typeok_shr(mp, ln, lt, rn, rt); 3021 shift: 3022 typeok_shift(ltp, lt, rn, rt); 3023 break; 3024 case LT: 3025 case LE: 3026 case GT: 3027 case GE: 3028 compare: 3029 return typeok_compare(op, ln, ltp, lt, rn, rtp, rt); 3030 case EQ: 3031 case NE: 3032 if (is_typeok_eq(ln, lt, rn, rt)) 3033 break; 3034 goto compare; 3035 case QUEST: 3036 return typeok_quest(lt, rn); 3037 case COLON: 3038 return typeok_colon(mp, ln, ltp, lt, rn, rtp, rt); 3039 case ASSIGN: 3040 case INIT: 3041 case FARG: 3042 case RETURN: 3043 if (!check_assign_types_compatible(op, arg, ln, rn)) 3044 return false; 3045 goto assign; 3046 case MULASS: 3047 case DIVASS: 3048 case MODASS: 3049 goto assign; 3050 case ADDASS: 3051 case SUBASS: 3052 if ((lt == PTR && !is_integer(rt)) || rt == PTR) { 3053 warn_incompatible_types(op, ltp, lt, rtp, rt); 3054 return false; 3055 } 3056 goto assign; 3057 case SHLASS: 3058 goto assign; 3059 case SHRASS: 3060 if (pflag && !is_uinteger(lt) && 3061 !(!allow_c90 && is_uinteger(rt))) { 3062 /* bitwise '%s' on signed value possibly nonportable */ 3063 warning(117, mp->m_name); 3064 } 3065 goto assign; 3066 case ANDASS: 3067 case XORASS: 3068 case ORASS: 3069 assign: 3070 return typeok_assign(op, ln, ltp, lt); 3071 case COMMA: 3072 if (!modtab[ln->tn_op].m_has_side_effect) 3073 check_null_effect(ln); 3074 break; 3075 default: 3076 break; 3077 } 3078 return true; 3079 } 3080 3081 /* Prints a warning if a strange operator is used on an enum type. */ 3082 static void 3083 check_bad_enum_operation(op_t op, const tnode_t *ln, const tnode_t *rn) 3084 { 3085 3086 if (!eflag) 3087 return; 3088 3089 /* Allow enum in array indices. */ 3090 if (op == PLUS && 3091 ((ln->tn_type->t_is_enum && rn->tn_type->t_tspec == PTR) || 3092 (rn->tn_type->t_is_enum && ln->tn_type->t_tspec == PTR))) { 3093 return; 3094 } 3095 3096 /* dubious operation on enum, op '%s' */ 3097 warning(241, op_name(op)); 3098 } 3099 3100 /* Prints a warning if an operator is applied to two different enum types. */ 3101 static void 3102 check_enum_type_mismatch(op_t op, int arg, const tnode_t *ln, const tnode_t *rn) 3103 { 3104 const mod_t *mp = &modtab[op]; 3105 3106 if (ln->tn_type->t_enum != rn->tn_type->t_enum) { 3107 switch (op) { 3108 case INIT: 3109 /* enum type mismatch between '%s' and '%s' in ... */ 3110 warning(210, 3111 type_name(ln->tn_type), type_name(rn->tn_type)); 3112 break; 3113 case FARG: 3114 /* function expects '%s', passing '%s' for arg #%d */ 3115 warning(156, 3116 type_name(ln->tn_type), type_name(rn->tn_type), 3117 arg); 3118 break; 3119 case RETURN: 3120 /* function has return type '%s' but returns '%s' */ 3121 warning(211, 3122 type_name(ln->tn_type), type_name(rn->tn_type)); 3123 break; 3124 default: 3125 /* enum type mismatch: '%s' '%s' '%s' */ 3126 warning(130, type_name(ln->tn_type), mp->m_name, 3127 type_name(rn->tn_type)); 3128 break; 3129 } 3130 } else if (Pflag && mp->m_comparison && op != EQ && op != NE) { 3131 if (eflag) 3132 /* dubious comparison of enums, op '%s' */ 3133 warning(243, mp->m_name); 3134 } 3135 } 3136 3137 /* Prints a warning if the operands mix between enum and integer. */ 3138 static void 3139 check_enum_int_mismatch(op_t op, int arg, const tnode_t *ln, const tnode_t *rn) 3140 { 3141 3142 if (!eflag) 3143 return; 3144 3145 switch (op) { 3146 case INIT: 3147 /* 3148 * Initialization with 0 is allowed. Otherwise, all implicit 3149 * initializations would need to be warned upon as well. 3150 */ 3151 if (!rn->tn_type->t_is_enum && rn->tn_op == CON && 3152 is_integer(rn->tn_type->t_tspec) && 3153 rn->tn_val.u.integer == 0) { 3154 return; 3155 } 3156 /* initialization of '%s' with '%s' */ 3157 warning(277, type_name(ln->tn_type), type_name(rn->tn_type)); 3158 break; 3159 case FARG: 3160 /* combination of '%s' and '%s', arg #%d */ 3161 warning(278, 3162 type_name(ln->tn_type), type_name(rn->tn_type), arg); 3163 break; 3164 case RETURN: 3165 /* combination of '%s' and '%s' in return */ 3166 warning(279, type_name(ln->tn_type), type_name(rn->tn_type)); 3167 break; 3168 default: 3169 /* combination of '%s' and '%s', op '%s' */ 3170 warning(242, type_name(ln->tn_type), type_name(rn->tn_type), 3171 op_name(op)); 3172 break; 3173 } 3174 } 3175 3176 static void 3177 typeok_enum(op_t op, const mod_t *mp, int arg, 3178 const tnode_t *ln, const type_t *ltp, 3179 const tnode_t *rn, const type_t *rtp) 3180 { 3181 if (mp->m_bad_on_enum && 3182 (ltp->t_is_enum || (mp->m_binary && rtp->t_is_enum))) { 3183 check_bad_enum_operation(op, ln, rn); 3184 } else if (mp->m_valid_on_enum && 3185 (ltp->t_is_enum && rtp != NULL && rtp->t_is_enum)) { 3186 check_enum_type_mismatch(op, arg, ln, rn); 3187 } else if (mp->m_valid_on_enum && 3188 (ltp->t_is_enum || (rtp != NULL && rtp->t_is_enum))) { 3189 check_enum_int_mismatch(op, arg, ln, rn); 3190 } 3191 } 3192 3193 /* Perform most type checks. Return whether the types are ok. */ 3194 bool 3195 typeok(op_t op, int arg, const tnode_t *ln, const tnode_t *rn) 3196 { 3197 3198 const mod_t *mp = &modtab[op]; 3199 3200 type_t *ltp = ln->tn_type; 3201 tspec_t lt = ltp->t_tspec; 3202 3203 type_t *rtp = mp->m_binary ? rn->tn_type : NULL; 3204 tspec_t rt = mp->m_binary ? rtp->t_tspec : NO_TSPEC; 3205 3206 if (Tflag && !typeok_scalar_strict_bool(op, mp, arg, ln, rn)) 3207 return false; 3208 if (!typeok_scalar(op, mp, ltp, lt, rtp, rt)) 3209 return false; 3210 3211 if (!typeok_op(op, mp, arg, ln, ltp, lt, rn, rtp, rt)) 3212 return false; 3213 3214 typeok_enum(op, mp, arg, ln, ltp, rn, rtp); 3215 return true; 3216 } 3217 3218 /* In traditional C, keep unsigned and promote FLOAT to DOUBLE. */ 3219 static tspec_t 3220 promote_trad(tspec_t t) 3221 { 3222 3223 if (t == UCHAR || t == USHORT) 3224 return UINT; 3225 if (t == CHAR || t == SCHAR || t == SHORT) 3226 return INT; 3227 if (t == FLOAT) 3228 return DOUBLE; 3229 if (t == ENUM) 3230 return INT; 3231 return t; 3232 } 3233 3234 /* 3235 * C99 6.3.1.1p2 requires for types with lower rank than int that "If an int 3236 * can represent all the values of the original type, the value is converted 3237 * to an int; otherwise it is converted to an unsigned int", and that "All 3238 * other types are unchanged by the integer promotions". 3239 */ 3240 static tspec_t 3241 promote_c90(const tnode_t *tn, tspec_t t, bool farg) 3242 { 3243 if (tn->tn_type->t_bitfield) { 3244 unsigned int width = tn->tn_type->t_bit_field_width; 3245 unsigned int int_width = size_in_bits(INT); 3246 // XXX: What about _Bool bit-fields, since C99? 3247 if (width < int_width) 3248 return INT; 3249 if (width == int_width) 3250 return is_uinteger(t) ? UINT : INT; 3251 return t; 3252 } 3253 3254 if (t == CHAR || t == SCHAR) 3255 return INT; 3256 if (t == UCHAR) 3257 return size_in_bits(CHAR) < size_in_bits(INT) ? INT : UINT; 3258 if (t == SHORT) 3259 return INT; 3260 if (t == USHORT) 3261 return size_in_bits(SHORT) < size_in_bits(INT) ? INT : UINT; 3262 if (t == ENUM) 3263 return INT; 3264 if (farg && t == FLOAT) 3265 return DOUBLE; 3266 return t; 3267 } 3268 3269 /* 3270 * Performs the "integer promotions" (C99 6.3.1.1p2), which convert small 3271 * integer types to either int or unsigned int. 3272 * 3273 * If allow_c90 is unset or the operand is a function argument with no type 3274 * information (no prototype or variable # of args), converts float to double. 3275 */ 3276 tnode_t * 3277 promote(op_t op, bool farg, tnode_t *tn) 3278 { 3279 3280 tspec_t ot = tn->tn_type->t_tspec; 3281 if (!is_arithmetic(ot)) 3282 return tn; 3283 3284 tspec_t nt = allow_c90 ? promote_c90(tn, ot, farg) : promote_trad(ot); 3285 if (nt == ot) 3286 return tn; 3287 3288 type_t *ntp = expr_dup_type(tn->tn_type); 3289 ntp->t_tspec = nt; 3290 /* 3291 * Keep t_is_enum even though t_tspec gets converted from 3292 * ENUM to INT, so we are later able to check compatibility 3293 * of enum types. 3294 */ 3295 return convert(op, 0, ntp, tn); 3296 } 3297 3298 static void 3299 convert_integer_from_floating(op_t op, const type_t *tp, const tnode_t *tn) 3300 { 3301 3302 if (op == CVT) 3303 /* cast from floating point '%s' to integer '%s' */ 3304 query_message(2, type_name(tn->tn_type), type_name(tp)); 3305 else 3306 /* implicit conversion from floating point '%s' to ... */ 3307 query_message(1, type_name(tn->tn_type), type_name(tp)); 3308 } 3309 3310 static bool 3311 should_warn_about_prototype_conversion(tspec_t nt, 3312 tspec_t ot, const tnode_t *ptn) 3313 { 3314 3315 if (nt == ot) 3316 return false; 3317 3318 if (nt == ENUM && ot == INT) 3319 return false; 3320 3321 if (is_floating(nt) != is_floating(ot) || 3322 portable_size_in_bits(nt) != portable_size_in_bits(ot)) { 3323 /* representation and/or width change */ 3324 if (!is_integer(ot)) 3325 return true; 3326 /* 3327 * XXX: Investigate whether this rule makes sense; see 3328 * tests/usr.bin/xlint/lint1/platform_long.c. 3329 */ 3330 return portable_size_in_bits(ot) > portable_size_in_bits(INT); 3331 } 3332 3333 if (!hflag) 3334 return false; 3335 3336 /* 3337 * If the types differ only in sign and the argument has the same 3338 * representation in both types, print no warning. 3339 */ 3340 if (ptn->tn_op == CON && is_integer(nt) && 3341 signed_type(nt) == signed_type(ot) && 3342 !msb(ptn->tn_val.u.integer, ot)) 3343 return false; 3344 3345 return true; 3346 } 3347 3348 /* 3349 * Warn if a prototype causes a type conversion that is different from what 3350 * would happen to the same argument in the absence of a prototype. This 3351 * check is intended for code that needs to stay compatible with pre-C90 C. 3352 * 3353 * Errors/warnings about illegal type combinations are already printed 3354 * in check_assign_types_compatible(). 3355 */ 3356 static void 3357 check_prototype_conversion(int arg, tspec_t nt, tspec_t ot, type_t *tp, 3358 tnode_t *tn) 3359 { 3360 3361 if (!is_arithmetic(nt) || !is_arithmetic(ot)) 3362 return; 3363 3364 /* 3365 * If the type of the formal parameter is char/short, a warning 3366 * would be useless, because functions declared the old style 3367 * can't expect char/short arguments. 3368 */ 3369 if (nt == CHAR || nt == SCHAR || nt == UCHAR || 3370 nt == SHORT || nt == USHORT) 3371 return; 3372 3373 /* apply the default promotion */ 3374 tnode_t *ptn = promote(NOOP, true, tn); 3375 ot = ptn->tn_type->t_tspec; 3376 3377 if (should_warn_about_prototype_conversion(nt, ot, ptn)) { 3378 /* argument #%d is converted from '%s' to '%s' ... */ 3379 warning(259, arg, type_name(tn->tn_type), type_name(tp)); 3380 } 3381 } 3382 3383 /* 3384 * When converting a large integer type to a small integer type, in some 3385 * cases the value of the actual expression is further restricted than the 3386 * type bounds, such as in (expr & 0xFF) or (expr % 100) or (expr >> 24). 3387 */ 3388 static bool 3389 can_represent(const type_t *tp, const tnode_t *tn) 3390 { 3391 3392 debug_step("%s: type '%s'", __func__, type_name(tp)); 3393 debug_node(tn); 3394 3395 uint64_t nmask = value_bits(width_in_bits(tp)); 3396 if (!is_uinteger(tp->t_tspec)) 3397 nmask >>= 1; 3398 3399 integer_constraints c = ic_expr(tn); 3400 if ((~c.bclr & ~nmask) == 0) 3401 return true; 3402 3403 integer_constraints tpc = ic_any(tp); 3404 if (is_uinteger(tp->t_tspec) 3405 ? tpc.umin <= c.umin && tpc.umax >= c.umax 3406 : tpc.smin <= c.smin && tpc.smax >= c.smax) 3407 return true; 3408 3409 return false; 3410 } 3411 3412 static void 3413 convert_integer_from_integer(op_t op, int arg, tspec_t nt, tspec_t ot, 3414 type_t *tp, tnode_t *tn) 3415 { 3416 3417 if (tn->tn_op == CON) 3418 return; 3419 3420 if (op == CVT) 3421 return; 3422 3423 if (Pflag && pflag && aflag > 0 && 3424 portable_size_in_bits(nt) > portable_size_in_bits(ot) && 3425 is_uinteger(nt) != is_uinteger(ot)) { 3426 if (op == FARG) { 3427 /* conversion to '%s' may sign-extend ... */ 3428 warning(297, type_name(tp), arg); 3429 } else { 3430 /* conversion to '%s' may sign-extend ... */ 3431 warning(131, type_name(tp)); 3432 } 3433 } 3434 3435 if (Pflag && portable_size_in_bits(nt) > portable_size_in_bits(ot) && 3436 (tn->tn_op == PLUS || tn->tn_op == MINUS || tn->tn_op == MULT || 3437 tn->tn_op == SHL)) { 3438 /* suggest cast from '%s' to '%s' on op '%s' to ... */ 3439 warning(324, type_name(gettyp(ot)), type_name(tp), 3440 op_name(tn->tn_op)); 3441 } 3442 3443 if (aflag > 0 && 3444 portable_size_in_bits(nt) < portable_size_in_bits(ot) && 3445 (ot == LONG || ot == ULONG || ot == LLONG || ot == ULLONG || 3446 aflag > 1) && 3447 !can_represent(tp, tn)) { 3448 if (op == FARG) { 3449 /* conversion from '%s' to '%s' may lose ... */ 3450 warning(298, 3451 type_name(tn->tn_type), type_name(tp), arg); 3452 } else { 3453 /* conversion from '%s' to '%s' may lose accuracy */ 3454 warning(132, 3455 type_name(tn->tn_type), type_name(tp)); 3456 } 3457 } 3458 3459 if (is_uinteger(nt) != is_uinteger(ot)) 3460 /* implicit conversion changes sign from '%s' to '%s' */ 3461 query_message(3, type_name(tn->tn_type), type_name(tp)); 3462 } 3463 3464 static void 3465 convert_integer_from_pointer(op_t op, tspec_t nt, type_t *tp, tnode_t *tn) 3466 { 3467 3468 if (tn->tn_op == CON) 3469 return; 3470 if (op != CVT) 3471 return; /* We already got an error. */ 3472 if (portable_size_in_bits(nt) >= portable_size_in_bits(PTR)) 3473 return; 3474 3475 if (pflag && size_in_bits(nt) >= size_in_bits(PTR)) { 3476 /* conversion of pointer to '%s' may lose bits */ 3477 warning(134, type_name(tp)); 3478 } else { 3479 /* conversion of pointer to '%s' loses bits */ 3480 warning(133, type_name(tp)); 3481 } 3482 } 3483 3484 static bool 3485 struct_starts_with(const type_t *struct_tp, const type_t *member_tp) 3486 { 3487 3488 return struct_tp->t_sou->sou_first_member != NULL && 3489 types_compatible(struct_tp->t_sou->sou_first_member->s_type, 3490 member_tp, true, false, NULL); 3491 } 3492 3493 static bool 3494 is_byte_array(const type_t *tp) 3495 { 3496 3497 return tp->t_tspec == ARRAY && 3498 (tp->t_subt->t_tspec == CHAR || tp->t_subt->t_tspec == UCHAR); 3499 } 3500 3501 static bool 3502 union_contains(const type_t *utp, const type_t *mtp) 3503 { 3504 for (const sym_t *mem = utp->t_sou->sou_first_member; 3505 mem != NULL; mem = mem->s_next) { 3506 if (types_compatible(mem->s_type, mtp, true, false, NULL)) 3507 return true; 3508 } 3509 return false; 3510 } 3511 3512 static bool 3513 should_warn_about_pointer_cast(const type_t *nstp, tspec_t nst, 3514 const type_t *ostp, tspec_t ost) 3515 { 3516 3517 while (nst == ARRAY) 3518 nstp = nstp->t_subt, nst = nstp->t_tspec; 3519 while (ost == ARRAY) 3520 ostp = ostp->t_subt, ost = ostp->t_tspec; 3521 3522 if (nst == STRUCT && ost == STRUCT && 3523 (struct_starts_with(nstp, ostp) || 3524 struct_starts_with(ostp, nstp))) 3525 return false; 3526 3527 if (is_incomplete(nstp) || is_incomplete(ostp)) 3528 return false; 3529 3530 if (nst == CHAR || nst == UCHAR) 3531 return false; /* for the sake of traditional C code */ 3532 if (ost == CHAR || ost == UCHAR) 3533 return false; /* for the sake of traditional C code */ 3534 3535 /* Allow cast between pointers to sockaddr variants. */ 3536 if (nst == STRUCT && ost == STRUCT) { 3537 debug_type(nstp); 3538 debug_type(ostp); 3539 const sym_t *nmem = nstp->t_sou->sou_first_member; 3540 const sym_t *omem = ostp->t_sou->sou_first_member; 3541 while (nmem != NULL && omem != NULL && 3542 types_compatible(nmem->s_type, omem->s_type, 3543 true, false, NULL)) 3544 nmem = nmem->s_next, omem = omem->s_next; 3545 if (nmem != NULL && is_byte_array(nmem->s_type)) 3546 return false; 3547 if (omem != NULL && is_byte_array(omem->s_type)) 3548 return false; 3549 if (nmem == NULL && omem == NULL) 3550 return false; 3551 } 3552 3553 if (nst == UNION || ost == UNION) { 3554 const type_t *union_tp = nst == UNION ? nstp : ostp; 3555 const type_t *other_tp = nst == UNION ? ostp : nstp; 3556 if (union_contains(union_tp, other_tp)) 3557 return false; 3558 } 3559 3560 if (is_struct_or_union(nst) && nstp->t_sou != ostp->t_sou) 3561 return true; 3562 3563 return portable_size_in_bits(nst) != portable_size_in_bits(ost); 3564 } 3565 3566 static void 3567 convert_pointer_from_pointer(type_t *ntp, tnode_t *tn) 3568 { 3569 const type_t *nstp = ntp->t_subt; 3570 const type_t *otp = tn->tn_type; 3571 const type_t *ostp = otp->t_subt; 3572 tspec_t nst = nstp->t_tspec; 3573 tspec_t ost = ostp->t_tspec; 3574 3575 if (nst == VOID || ost == VOID) { 3576 /* TODO: C99 behaves like C90 here. */ 3577 if ((!allow_trad && !allow_c99) && (nst == FUNC || ost == FUNC)) { 3578 const char *nts, *ots; 3579 /* null pointers are already handled in convert() */ 3580 *(nst == FUNC ? &nts : &ots) = "function pointer"; 3581 *(nst == VOID ? &nts : &ots) = "'void *'"; 3582 /* ANSI C forbids conversion of %s to %s */ 3583 warning(303, ots, nts); 3584 } 3585 return; 3586 } 3587 if (nst == FUNC && ost == FUNC) 3588 return; 3589 if (nst == FUNC || ost == FUNC) { 3590 /* converting '%s' to '%s' is questionable */ 3591 warning(229, type_name(otp), type_name(ntp)); 3592 return; 3593 } 3594 3595 if (hflag && alignment_in_bits(nstp) > alignment_in_bits(ostp) && 3596 ost != CHAR && ost != UCHAR && 3597 !is_incomplete(ostp) && 3598 !(nst == UNION && union_contains(nstp, ostp))) { 3599 /* converting '%s' to '%s' increases alignment ... */ 3600 warning(135, type_name(otp), type_name(ntp), 3601 alignment_in_bits(ostp) / CHAR_SIZE, 3602 alignment_in_bits(nstp) / CHAR_SIZE); 3603 } 3604 3605 if (cflag && should_warn_about_pointer_cast(nstp, nst, ostp, ost)) { 3606 /* pointer cast from '%s' to '%s' may be troublesome */ 3607 warning(247, type_name(otp), type_name(ntp)); 3608 } 3609 } 3610 3611 /* 3612 * Insert a conversion operator, which converts the type of the node 3613 * to another given type. 3614 * 3615 * Possible values for 'op': 3616 * CVT a cast-expression 3617 * binary integer promotion for one of the operands, or a usual 3618 * arithmetic conversion 3619 * binary plain or compound assignments to bit-fields 3620 * FARG 'arg' is the number of the argument (used for warnings) 3621 * NOOP several other implicit conversions 3622 * ... 3623 */ 3624 tnode_t * 3625 convert(op_t op, int arg, type_t *tp, tnode_t *tn) 3626 { 3627 tspec_t nt = tp->t_tspec; 3628 tspec_t ot = tn->tn_type->t_tspec; 3629 3630 if (allow_trad && allow_c90 && op == FARG) 3631 check_prototype_conversion(arg, nt, ot, tp, tn); 3632 3633 if (nt == BOOL) { 3634 /* No further checks. */ 3635 3636 } else if (is_integer(nt)) { 3637 if (ot == BOOL) { 3638 /* No further checks. */ 3639 } else if (is_integer(ot)) 3640 convert_integer_from_integer(op, arg, nt, ot, tp, tn); 3641 else if (is_floating(ot)) 3642 convert_integer_from_floating(op, tp, tn); 3643 else if (ot == PTR) 3644 convert_integer_from_pointer(op, nt, tp, tn); 3645 3646 } else if (is_floating(nt)) { 3647 /* No further checks. */ 3648 3649 } else if (nt == PTR) { 3650 if (is_null_pointer(tn)) { 3651 /* a null pointer may be assigned to any pointer. */ 3652 } else if (ot == PTR && op == CVT) 3653 convert_pointer_from_pointer(tp, tn); 3654 } 3655 3656 tnode_t *ntn = expr_alloc_tnode(); 3657 ntn->tn_op = CVT; 3658 ntn->tn_type = tp; 3659 ntn->tn_cast = op == CVT; 3660 ntn->tn_sys |= tn->tn_sys; 3661 ntn->tn_right = NULL; 3662 if (tn->tn_op != CON || nt == VOID) { 3663 ntn->tn_left = tn; 3664 } else { 3665 ntn->tn_op = CON; 3666 convert_constant(op, arg, ntn->tn_type, &ntn->tn_val, 3667 &tn->tn_val); 3668 } 3669 3670 return ntn; 3671 } 3672 3673 static void 3674 convert_constant_floating(op_t op, int arg, tspec_t ot, const type_t *tp, 3675 tspec_t nt, val_t *v, val_t *nv) 3676 { 3677 long double max = 0.0, min = 0.0; 3678 3679 switch (nt) { 3680 case CHAR: 3681 max = TARG_CHAR_MAX; min = TARG_CHAR_MIN; break; 3682 case UCHAR: 3683 max = TARG_UCHAR_MAX; min = 0; break; 3684 case SCHAR: 3685 max = TARG_SCHAR_MAX; min = TARG_SCHAR_MIN; break; 3686 case SHORT: 3687 max = TARG_SHRT_MAX; min = TARG_SHRT_MIN; break; 3688 case USHORT: 3689 max = TARG_USHRT_MAX; min = 0; break; 3690 case ENUM: 3691 case INT: 3692 max = TARG_INT_MAX; min = TARG_INT_MIN; break; 3693 case UINT: 3694 max = TARG_UINT_MAX; min = 0; break; 3695 case LONG: 3696 max = TARG_LONG_MAX; min = TARG_LONG_MIN; break; 3697 case ULONG: 3698 max = TARG_ULONG_MAX; min = 0; break; 3699 case LLONG: 3700 max = LLONG_MAX; min = LLONG_MIN; break; 3701 case ULLONG: 3702 max = ULLONG_MAX; min = 0; break; 3703 case FLOAT: 3704 case FCOMPLEX: 3705 max = FLT_MAX; min = -FLT_MAX; break; 3706 case DOUBLE: 3707 case DCOMPLEX: 3708 max = DBL_MAX; min = -DBL_MAX; break; 3709 case PTR: 3710 /* Already got an error because of float --> ptr */ 3711 case LDOUBLE: 3712 case LCOMPLEX: 3713 /* LINTED 248 */ 3714 max = LDBL_MAX; min = -max; break; 3715 default: 3716 lint_assert(/*CONSTCOND*/false); 3717 } 3718 if (v->u.floating > max || v->u.floating < min) { 3719 lint_assert(nt != LDOUBLE); 3720 if (op == FARG) { 3721 /* conversion of '%s' to '%s' is out of range, ... */ 3722 warning(295, 3723 type_name(gettyp(ot)), type_name(tp), arg); 3724 } else { 3725 /* conversion of '%s' to '%s' is out of range */ 3726 warning(119, type_name(gettyp(ot)), type_name(tp)); 3727 } 3728 v->u.floating = v->u.floating > 0 ? max : min; 3729 } 3730 3731 if (nt == FLOAT || nt == FCOMPLEX) 3732 nv->u.floating = (float)v->u.floating; 3733 else if (nt == DOUBLE || nt == DCOMPLEX) 3734 nv->u.floating = (double)v->u.floating; 3735 else if (nt == LDOUBLE || nt == LCOMPLEX) 3736 nv->u.floating = v->u.floating; 3737 else 3738 nv->u.integer = (int64_t)v->u.floating; 3739 } 3740 3741 static bool 3742 convert_constant_to_floating(tspec_t nt, val_t *nv, 3743 tspec_t ot, const val_t *v) 3744 { 3745 if (nt == FLOAT) { 3746 nv->u.floating = (ot == PTR || is_uinteger(ot)) ? 3747 (float)(uint64_t)v->u.integer : (float)v->u.integer; 3748 } else if (nt == DOUBLE) { 3749 nv->u.floating = (ot == PTR || is_uinteger(ot)) ? 3750 (double)(uint64_t)v->u.integer : (double)v->u.integer; 3751 } else if (nt == LDOUBLE) { 3752 nv->u.floating = (ot == PTR || is_uinteger(ot)) 3753 ? (long double)(uint64_t)v->u.integer 3754 : (long double)v->u.integer; 3755 } else 3756 return false; 3757 return true; 3758 } 3759 3760 /* 3761 * Print a warning if bits which were set are lost due to the conversion. 3762 * This can happen with operator ORASS only. 3763 */ 3764 static void 3765 convert_constant_check_range_bitor(size_t nsz, size_t osz, const val_t *v, 3766 uint64_t xmask, op_t op) 3767 { 3768 if (nsz < osz && (v->u.integer & xmask) != 0) { 3769 /* constant truncated by conversion, op '%s' */ 3770 warning(306, op_name(op)); 3771 } 3772 } 3773 3774 /* 3775 * Print a warning if additional bits are not all 1 3776 * and the most significant bit of the old value is 1, 3777 * or if at least one (but not all) removed bit was 0. 3778 */ 3779 static void 3780 convert_constant_check_range_bitand(size_t nsz, size_t osz, 3781 uint64_t xmask, const val_t *nv, 3782 tspec_t ot, const val_t *v, 3783 const type_t *tp, op_t op) 3784 { 3785 if (nsz > osz && 3786 (nv->u.integer & bit((unsigned int)(osz - 1))) != 0 && 3787 (nv->u.integer & xmask) != xmask) { 3788 /* extra bits set to 0 in conversion of '%s' to '%s', ... */ 3789 warning(309, type_name(gettyp(ot)), 3790 type_name(tp), op_name(op)); 3791 } else if (nsz < osz && 3792 (v->u.integer & xmask) != xmask && 3793 (v->u.integer & xmask) != 0) { 3794 /* constant truncated by conversion, op '%s' */ 3795 warning(306, op_name(op)); 3796 } 3797 } 3798 3799 static void 3800 convert_constant_check_range_signed(op_t op, int arg) 3801 { 3802 if (op == ASSIGN) { 3803 /* assignment of negative constant to unsigned type */ 3804 warning(164); 3805 } else if (op == INIT) { 3806 /* initialization of unsigned with negative constant */ 3807 warning(221); 3808 } else if (op == FARG) { 3809 /* conversion of negative constant to unsigned type, ... */ 3810 warning(296, arg); 3811 } else if (modtab[op].m_comparison) { 3812 /* handled by check_integer_comparison() */ 3813 } else { 3814 /* conversion of negative constant to unsigned type */ 3815 warning(222); 3816 } 3817 } 3818 3819 /* 3820 * Loss of significant bit(s). All truncated bits of unsigned types or all 3821 * truncated bits plus the msb of the target for signed types are considered 3822 * to be significant bits. Loss of significant bits means that at least one 3823 * of the bits was set in an unsigned type or that at least one but not all 3824 * of the bits was set in a signed type. Loss of significant bits means that 3825 * it is not possible, also not with necessary casts, to convert back to the 3826 * original type. An example for a necessary cast is: 3827 * char c; int i; c = 128; 3828 * i = c; ** yields -128 ** 3829 * i = (unsigned char)c; ** yields 128 ** 3830 */ 3831 static void 3832 warn_constant_check_range_truncated(op_t op, int arg, const type_t *tp, 3833 tspec_t ot) 3834 { 3835 if (op == ASSIGN && tp->t_bitfield) 3836 /* precision lost in bit-field assignment */ 3837 warning(166); 3838 else if (op == ASSIGN) 3839 /* constant truncated by assignment */ 3840 warning(165); 3841 else if (op == INIT && tp->t_bitfield) 3842 /* bit-field initializer does not fit */ 3843 warning(180); 3844 else if (op == INIT) 3845 /* initializer does not fit */ 3846 warning(178); 3847 else if (op == CASE) 3848 /* case label affected by conversion */ 3849 warning(196); 3850 else if (op == FARG) 3851 /* conversion of '%s' to '%s' is out of range, arg #%d */ 3852 warning(295, type_name(gettyp(ot)), type_name(tp), arg); 3853 else 3854 /* conversion of '%s' to '%s' is out of range */ 3855 warning(119, type_name(gettyp(ot)), type_name(tp)); 3856 } 3857 3858 static void 3859 warn_constant_check_range_loss(op_t op, int arg, const type_t *tp, 3860 tspec_t ot) 3861 { 3862 if (op == ASSIGN && tp->t_bitfield) 3863 /* precision lost in bit-field assignment */ 3864 warning(166); 3865 else if (op == INIT && tp->t_bitfield) 3866 /* bit-field initializer out of range */ 3867 warning(11); 3868 else if (op == CASE) 3869 /* case label affected by conversion */ 3870 warning(196); 3871 else if (op == FARG) 3872 /* conversion of '%s' to '%s' is out of range, arg #%d */ 3873 warning(295, type_name(gettyp(ot)), type_name(tp), arg); 3874 else 3875 /* conversion of '%s' to '%s' is out of range */ 3876 warning(119, type_name(gettyp(ot)), type_name(tp)); 3877 } 3878 3879 static void 3880 convert_constant_check_range(tspec_t ot, const type_t *tp, tspec_t nt, 3881 op_t op, int arg, const val_t *v, val_t *nv) 3882 { 3883 unsigned int obitsz, nbitsz; 3884 uint64_t xmask, xmsk1; 3885 3886 obitsz = size_in_bits(ot); 3887 nbitsz = tp->t_bitfield ? tp->t_bit_field_width : size_in_bits(nt); 3888 xmask = value_bits(nbitsz) ^ value_bits(obitsz); 3889 xmsk1 = value_bits(nbitsz) ^ value_bits(obitsz - 1); 3890 /* 3891 * For bitwise operations we are not interested in the arithmetic 3892 * value, but in the bits itself. 3893 */ 3894 if (op == ORASS || op == BITOR || op == BITXOR) { 3895 convert_constant_check_range_bitor( 3896 nbitsz, obitsz, v, xmask, op); 3897 } else if (op == ANDASS || op == BITAND) { 3898 convert_constant_check_range_bitand( 3899 nbitsz, obitsz, xmask, nv, ot, v, tp, op); 3900 } else if ((nt != PTR && is_uinteger(nt)) && 3901 (ot != PTR && !is_uinteger(ot)) && 3902 v->u.integer < 0) 3903 convert_constant_check_range_signed(op, arg); 3904 else if (nv->u.integer != v->u.integer && nbitsz <= obitsz && 3905 (v->u.integer & xmask) != 0 && 3906 (is_uinteger(ot) || (v->u.integer & xmsk1) != xmsk1)) 3907 warn_constant_check_range_truncated(op, arg, tp, ot); 3908 else if (nv->u.integer != v->u.integer) 3909 warn_constant_check_range_loss(op, arg, tp, ot); 3910 } 3911 3912 /* 3913 * Converts a typed constant to a constant of another type. 3914 * 3915 * op operator which requires conversion 3916 * arg if op is FARG, # of argument 3917 * tp type to which to convert the constant 3918 * nv new constant 3919 * v old constant 3920 */ 3921 void 3922 convert_constant(op_t op, int arg, const type_t *tp, val_t *nv, val_t *v) 3923 { 3924 /* 3925 * TODO: make 'v' const; the name of this function does not suggest 3926 * that it modifies 'v'. 3927 */ 3928 tspec_t ot = v->v_tspec; 3929 tspec_t nt = nv->v_tspec = tp->t_tspec; 3930 bool range_check = false; 3931 3932 if (nt == BOOL) { /* C99 6.3.1.2 */ 3933 nv->v_unsigned_since_c90 = false; 3934 nv->u.integer = is_nonzero_val(v) ? 1 : 0; 3935 return; 3936 } 3937 3938 if (ot == FLOAT || ot == DOUBLE || ot == LDOUBLE) 3939 convert_constant_floating(op, arg, ot, tp, nt, v, nv); 3940 else if (!convert_constant_to_floating(nt, nv, ot, v)) { 3941 range_check = true; /* Check for lost precision. */ 3942 nv->u.integer = v->u.integer; 3943 } 3944 3945 if (allow_trad && allow_c90 && v->v_unsigned_since_c90 && 3946 (is_floating(nt) || ( 3947 (is_integer(nt) && !is_uinteger(nt) && 3948 portable_size_in_bits(nt) > portable_size_in_bits(ot))))) { 3949 /* ANSI C treats constant as unsigned */ 3950 warning(157); 3951 v->v_unsigned_since_c90 = false; 3952 } 3953 3954 if (is_integer(nt)) { 3955 nv->u.integer = convert_integer(nv->u.integer, nt, 3956 tp->t_bitfield ? tp->t_bit_field_width : size_in_bits(nt)); 3957 } 3958 3959 if (range_check && op != CVT) 3960 convert_constant_check_range(ot, tp, nt, op, arg, v, nv); 3961 } 3962 3963 /* 3964 * Create a constant node for sizeof. 3965 */ 3966 tnode_t * 3967 build_sizeof(const type_t *tp) 3968 { 3969 unsigned int size_in_bytes = type_size_in_bits(tp) / CHAR_SIZE; 3970 tnode_t *tn = build_integer_constant(SIZEOF_TSPEC, size_in_bytes); 3971 tn->tn_system_dependent = true; 3972 debug_step("build_sizeof '%s' = %u", type_name(tp), size_in_bytes); 3973 return tn; 3974 } 3975 3976 /* 3977 * Create a constant node for offsetof. 3978 */ 3979 /* ARGSUSED */ /* FIXME: See implementation comments. */ 3980 tnode_t * 3981 build_offsetof(const type_t *tp, const sym_t *sym) 3982 { 3983 3984 if (!is_struct_or_union(tp->t_tspec)) 3985 /* unacceptable operand of '%s' */ 3986 error(111, "offsetof"); 3987 3988 /* FIXME: Don't wrongly use the size of the whole type, use sym. */ 3989 unsigned int offset_in_bytes = type_size_in_bits(tp) / CHAR_SIZE; 3990 tnode_t *tn = build_integer_constant(SIZEOF_TSPEC, offset_in_bytes); 3991 tn->tn_system_dependent = true; 3992 return tn; 3993 } 3994 3995 unsigned int 3996 type_size_in_bits(const type_t *tp) 3997 { 3998 3999 unsigned int elem = 1; 4000 bool flex = false; 4001 lint_assert(tp != NULL); 4002 while (tp->t_tspec == ARRAY) { 4003 flex = true; /* allow c99 flex arrays [] [0] */ 4004 elem *= tp->t_dim; 4005 tp = tp->t_subt; 4006 } 4007 if (elem == 0 && !flex) { 4008 /* cannot take size/alignment of incomplete type */ 4009 error(143); 4010 elem = 1; 4011 } 4012 4013 unsigned int elsz; 4014 switch (tp->t_tspec) { 4015 case VOID: 4016 /* cannot take size/alignment of void */ 4017 error(146); 4018 elsz = 1; 4019 break; 4020 case FUNC: 4021 /* cannot take size/alignment of function type '%s' */ 4022 error(144, type_name(tp)); 4023 elsz = 1; 4024 break; 4025 case STRUCT: 4026 case UNION: 4027 if (is_incomplete(tp)) { 4028 /* cannot take size/alignment of incomplete type */ 4029 error(143); 4030 elsz = 1; 4031 } else { 4032 elsz = tp->t_sou->sou_size_in_bits; 4033 } 4034 break; 4035 case ENUM: 4036 if (is_incomplete(tp)) { 4037 /* cannot take size/alignment of incomplete type */ 4038 warning(143); 4039 } 4040 /* FALLTHROUGH */ 4041 default: 4042 if (tp->t_bitfield) { 4043 /* cannot take size/alignment of bit-field */ 4044 error(145); 4045 } 4046 elsz = size_in_bits(tp->t_tspec); 4047 lint_assert(elsz > 0); 4048 break; 4049 } 4050 4051 return elem * elsz; 4052 } 4053 4054 /* C11 6.5.3.4, GCC */ 4055 tnode_t * 4056 build_alignof(const type_t *tp) 4057 { 4058 if (tp->t_tspec == FUNC) { 4059 /* cannot take size/alignment of function type '%s' */ 4060 error(144, type_name(tp)); 4061 return NULL; 4062 } 4063 if (tp->t_tspec == VOID) { 4064 /* cannot take size/alignment of void */ 4065 error(146); 4066 return NULL; 4067 } 4068 if (is_incomplete(tp)) { 4069 /* cannot take size/alignment of incomplete type */ 4070 error(143); 4071 return NULL; 4072 } 4073 if (tp->t_bitfield) { 4074 /* cannot take size/alignment of bit-field */ 4075 error(145); 4076 return NULL; 4077 } 4078 return build_integer_constant(SIZEOF_TSPEC, 4079 (int64_t)alignment_in_bits(tp) / CHAR_SIZE); 4080 } 4081 4082 static tnode_t * 4083 cast_to_union(tnode_t *otn, type_t *ntp) 4084 { 4085 4086 if (!allow_gcc) { 4087 /* union cast is a GCC extension */ 4088 error(328); 4089 return NULL; 4090 } 4091 4092 for (const sym_t *m = ntp->t_sou->sou_first_member; 4093 m != NULL; m = m->s_next) { 4094 if (types_compatible(m->s_type, otn->tn_type, 4095 false, false, NULL)) { 4096 tnode_t *ntn = expr_alloc_tnode(); 4097 ntn->tn_op = CVT; 4098 ntn->tn_type = ntp; 4099 ntn->tn_cast = true; 4100 ntn->tn_left = otn; 4101 ntn->tn_right = NULL; 4102 return ntn; 4103 } 4104 } 4105 4106 /* type '%s' is not a member of '%s' */ 4107 error(329, type_name(otn->tn_type), type_name(ntp)); 4108 return NULL; 4109 } 4110 4111 /* 4112 * Type casts. 4113 */ 4114 tnode_t * 4115 cast(tnode_t *tn, type_t *tp) 4116 { 4117 4118 if (tn == NULL) 4119 return NULL; 4120 4121 tn = cconv(tn); 4122 4123 lint_assert(tp != NULL); 4124 tspec_t nt = tp->t_tspec; 4125 tspec_t ot = tn->tn_type->t_tspec; 4126 4127 if (nt == VOID) { 4128 /* 4129 * C90 6.3.4, C99 6.5.4p2 and C11 6.5.4p2 allow any type to 4130 * be cast to void. The only other allowed casts are from a 4131 * scalar type to a scalar type. 4132 */ 4133 } else if (nt == UNION) 4134 return cast_to_union(tn, tp); 4135 else if (nt == STRUCT || nt == ARRAY || nt == FUNC) { 4136 /* Casting to a struct is an undocumented GCC extension. */ 4137 if (!(allow_gcc && nt == STRUCT)) 4138 goto invalid_cast; 4139 } else if (is_struct_or_union(ot)) 4140 goto invalid_cast; 4141 else if (ot == VOID) { 4142 /* improper cast of void expression */ 4143 error(148); 4144 return NULL; 4145 } else if (is_integer(nt) && is_scalar(ot)) { 4146 /* ok */ 4147 } else if (is_floating(nt) && is_arithmetic(ot)) { 4148 /* ok */ 4149 } else if (nt == PTR && is_integer(ot)) { 4150 /* ok */ 4151 } else if (nt == PTR && ot == PTR) { 4152 if (!tp->t_subt->t_const && tn->tn_type->t_subt->t_const) { 4153 if (hflag) 4154 /* cast discards 'const' from type '%s' */ 4155 warning(275, type_name(tn->tn_type)); 4156 } 4157 } else 4158 goto invalid_cast; 4159 4160 if (any_query_enabled && types_compatible(tp, tn->tn_type, 4161 false, false, NULL)) { 4162 /* no-op cast from '%s' to '%s' */ 4163 query_message(6, type_name(tn->tn_type), type_name(tp)); 4164 } 4165 4166 tn = convert(CVT, 0, tp, tn); 4167 tn->tn_cast = true; 4168 4169 return tn; 4170 4171 invalid_cast: 4172 /* invalid cast from '%s' to '%s' */ 4173 error(147, type_name(tn->tn_type), type_name(tp)); 4174 return NULL; 4175 } 4176 4177 /* 4178 * Create the node for a function argument. 4179 * All necessary conversions and type checks are done in 4180 * build_function_call because build_function_argument has no 4181 * information about expected argument types. 4182 */ 4183 tnode_t * 4184 build_function_argument(tnode_t *args, tnode_t *arg) 4185 { 4186 /* 4187 * If there was a serious error in the expression for the argument, 4188 * create a dummy argument so the positions of the remaining arguments 4189 * will not change. 4190 */ 4191 if (arg == NULL) 4192 arg = build_integer_constant(INT, 0); 4193 4194 return new_tnode(PUSH, arg->tn_sys, arg->tn_type, arg, args); 4195 } 4196 4197 /* 4198 * Compare the type of an argument with the corresponding type of a 4199 * prototype parameter. If it is a valid combination, but both types 4200 * are not the same, insert a conversion to convert the argument into 4201 * the type of the parameter. 4202 */ 4203 static tnode_t * 4204 check_prototype_argument( 4205 int n, /* pos of arg */ 4206 type_t *tp, /* expected type (from prototype) */ 4207 tnode_t *tn) /* argument */ 4208 { 4209 tnode_t *ln = xcalloc(1, sizeof(*ln)); 4210 ln->tn_type = expr_unqualified_type(tp); 4211 ln->tn_lvalue = true; 4212 if (typeok(FARG, n, ln, tn)) { 4213 bool dowarn; 4214 if (!types_compatible(tp, tn->tn_type, 4215 true, false, (dowarn = false, &dowarn)) || dowarn) 4216 tn = convert(FARG, n, tp, tn); 4217 } 4218 free(ln); 4219 return tn; 4220 } 4221 4222 /* 4223 * Check types of all function arguments and insert conversions, 4224 * if necessary. 4225 */ 4226 static tnode_t * 4227 check_function_arguments(type_t *ftp, tnode_t *args) 4228 { 4229 /* get # of parameters in the prototype */ 4230 int npar = 0; 4231 for (sym_t *asym = ftp->t_args; asym != NULL; asym = asym->s_next) 4232 npar++; 4233 4234 /* get # of arguments in the function call */ 4235 int narg = 0; 4236 for (tnode_t *arg = args; arg != NULL; arg = arg->tn_right) 4237 narg++; 4238 4239 sym_t *asym = ftp->t_args; 4240 if (ftp->t_proto && npar != narg && !(ftp->t_vararg && npar < narg)) { 4241 /* argument mismatch: %d %s passed, %d expected */ 4242 error(150, narg, narg > 1 ? "arguments" : "argument", npar); 4243 asym = NULL; 4244 } 4245 4246 for (int n = 1; n <= narg; n++) { 4247 4248 /* 4249 * The rightmost argument is at the top of the argument 4250 * subtree. 4251 */ 4252 tnode_t *arg = args; 4253 for (int i = narg; i > n; i--, arg = arg->tn_right) 4254 continue; 4255 4256 /* some things which are always not allowed */ 4257 tspec_t at = arg->tn_left->tn_type->t_tspec; 4258 if (at == VOID) { 4259 /* void expressions may not be arguments, arg #%d */ 4260 error(151, n); 4261 return NULL; 4262 } else if (is_struct_or_union(at) && 4263 is_incomplete(arg->tn_left->tn_type)) { 4264 /* argument cannot have unknown size, arg #%d */ 4265 error(152, n); 4266 return NULL; 4267 } else if (is_integer(at) && 4268 arg->tn_left->tn_type->t_is_enum && 4269 is_incomplete(arg->tn_left->tn_type)) { 4270 /* argument cannot have unknown size, arg #%d */ 4271 warning(152, n); 4272 } 4273 4274 /* class conversions (arg in value context) */ 4275 arg->tn_left = cconv(arg->tn_left); 4276 4277 if (asym != NULL) { 4278 arg->tn_left = check_prototype_argument( 4279 n, asym->s_type, arg->tn_left); 4280 } else 4281 arg->tn_left = promote(NOOP, true, arg->tn_left); 4282 arg->tn_type = arg->tn_left->tn_type; 4283 4284 if (asym != NULL) 4285 asym = asym->s_next; 4286 } 4287 4288 return args; 4289 } 4290 4291 /* 4292 * Create the node for a function call. Also check types of 4293 * function arguments and insert conversions, if necessary. 4294 */ 4295 tnode_t * 4296 build_function_call(tnode_t *func, bool sys, tnode_t *args) 4297 { 4298 4299 if (func == NULL) 4300 return NULL; 4301 4302 op_t fcop = func->tn_op == NAME && func->tn_type->t_tspec == FUNC 4303 ? CALL : ICALL; 4304 4305 check_ctype_function_call(func, args); 4306 4307 /* Turn the function name into a pointer to the function. */ 4308 func = cconv(func); 4309 4310 if (func->tn_type->t_tspec != PTR || 4311 func->tn_type->t_subt->t_tspec != FUNC) { 4312 /* cannot call '%s', must be a function */ 4313 error(149, type_name(func->tn_type)); 4314 return NULL; 4315 } 4316 4317 args = check_function_arguments(func->tn_type->t_subt, args); 4318 4319 return new_tnode(fcop, sys, func->tn_type->t_subt->t_subt, func, args); 4320 } 4321 4322 /* 4323 * Return the value of an integral constant expression. 4324 * If the expression is not constant or its type is not an integer 4325 * type, an error message is printed. 4326 */ 4327 val_t * 4328 integer_constant(tnode_t *tn, bool required) 4329 { 4330 4331 if (tn != NULL) 4332 tn = cconv(tn); 4333 if (tn != NULL) 4334 tn = promote(NOOP, false, tn); 4335 4336 val_t *v = xcalloc(1, sizeof(*v)); 4337 4338 if (tn == NULL) { 4339 lint_assert(seen_error); 4340 debug_step("constant node is null; returning 1 instead"); 4341 v->v_tspec = INT; 4342 v->u.integer = 1; 4343 return v; 4344 } 4345 4346 v->v_tspec = tn->tn_type->t_tspec; 4347 4348 if (tn->tn_op == CON) { 4349 lint_assert(tn->tn_type->t_tspec == tn->tn_val.v_tspec); 4350 if (is_integer(tn->tn_val.v_tspec)) { 4351 v->v_unsigned_since_c90 = 4352 tn->tn_val.v_unsigned_since_c90; 4353 v->u.integer = tn->tn_val.u.integer; 4354 return v; 4355 } 4356 v->u.integer = (int64_t)tn->tn_val.u.floating; 4357 } else { 4358 v->u.integer = 1; 4359 } 4360 4361 if (required) 4362 /* integral constant expression expected */ 4363 error(55); 4364 else 4365 /* variable array dimension is a C99/GCC extension */ 4366 c99ism(318); 4367 4368 if (!is_integer(v->v_tspec)) 4369 v->v_tspec = INT; 4370 4371 return v; 4372 } 4373 4374 static bool 4375 is_constcond_false(const tnode_t *tn, tspec_t t) 4376 { 4377 return (t == BOOL || t == INT) && 4378 tn->tn_op == CON && tn->tn_val.u.integer == 0; 4379 } 4380 4381 /* 4382 * Perform some tests on expressions which can't be done in build_binary() 4383 * and functions called by build_binary(). These tests must be done here 4384 * because we need some information about the context in which the operations 4385 * are performed. 4386 * After all tests are performed and dofreeblk is true, expr() frees the 4387 * memory which is used for the expression. 4388 */ 4389 void 4390 expr(tnode_t *tn, bool vctx, bool cond, bool dofreeblk, bool is_do_while) 4391 { 4392 4393 if (tn == NULL) { /* in case of errors */ 4394 expr_free_all(); 4395 return; 4396 } 4397 4398 /* expr() is also called in global initializations */ 4399 if (dcs->d_kind != DLK_EXTERN && !is_do_while) 4400 check_statement_reachable(); 4401 4402 check_expr_misc(tn, vctx, cond, !cond, false, false, false); 4403 if (tn->tn_op == ASSIGN && !tn->tn_parenthesized) { 4404 if (hflag && cond) 4405 /* assignment in conditional context */ 4406 warning(159); 4407 } else if (tn->tn_op == CON) { 4408 if (hflag && cond && !constcond_flag && 4409 !tn->tn_system_dependent && 4410 !(is_do_while && 4411 is_constcond_false(tn, tn->tn_type->t_tspec))) 4412 /* constant in conditional context */ 4413 warning(161); 4414 } 4415 if (!modtab[tn->tn_op].m_has_side_effect) { 4416 /* 4417 * for left operands of COMMA this warning is already 4418 * printed 4419 */ 4420 if (tn->tn_op != COMMA && !vctx && !cond) 4421 check_null_effect(tn); 4422 } 4423 debug_node(tn); 4424 4425 /* free the tree memory */ 4426 if (dofreeblk) 4427 expr_free_all(); 4428 } 4429 4430 /* 4431 * Checks the range of array indices, if possible. 4432 * amper is set if only the address of the element is used. This 4433 * means that the index is allowed to refer to the first element 4434 * after the array. 4435 */ 4436 static void 4437 check_array_index(tnode_t *tn, bool amper) 4438 { 4439 const tnode_t *ln = tn->tn_left; 4440 const tnode_t *rn = tn->tn_right; 4441 4442 /* We can only check constant indices. */ 4443 if (rn->tn_op != CON) 4444 return; 4445 4446 /* Return if the left node does not stem from an array. */ 4447 if (ln->tn_op != ADDR) 4448 return; 4449 if (ln->tn_left->tn_op != STRING && ln->tn_left->tn_op != NAME) 4450 return; 4451 if (ln->tn_left->tn_type->t_tspec != ARRAY) 4452 return; 4453 4454 /* 4455 * For incomplete array types, we can print a warning only if 4456 * the index is negative. 4457 */ 4458 if (is_incomplete(ln->tn_left->tn_type) && rn->tn_val.u.integer >= 0) 4459 return; 4460 4461 /* Get the size of one array element */ 4462 int elsz = length_in_bits(ln->tn_type->t_subt, NULL); 4463 if (elsz == 0) 4464 return; 4465 elsz /= CHAR_SIZE; 4466 4467 /* Change the unit of the index from bytes to element size. */ 4468 int64_t con = is_uinteger(rn->tn_type->t_tspec) 4469 ? (int64_t)((uint64_t)rn->tn_val.u.integer / elsz) 4470 : rn->tn_val.u.integer / elsz; 4471 4472 int dim = ln->tn_left->tn_type->t_dim + (amper ? 1 : 0); 4473 4474 if (!is_uinteger(rn->tn_type->t_tspec) && con < 0) { 4475 /* array subscript cannot be negative: %ld */ 4476 warning(167, (long)con); 4477 } else if (dim > 0 && (uint64_t)con >= (uint64_t)dim) { 4478 /* array subscript cannot be > %d: %ld */ 4479 warning(168, dim - 1, (long)con); 4480 } 4481 } 4482 4483 static void 4484 check_expr_addr(const tnode_t *ln, bool szof, bool fcall) 4485 { 4486 /* XXX: Taking warn_about_unreachable into account here feels wrong. */ 4487 if (ln->tn_op == NAME && (reached || !warn_about_unreachable)) { 4488 if (!szof) 4489 mark_as_set(ln->tn_sym); 4490 mark_as_used(ln->tn_sym, fcall, szof); 4491 } 4492 if (ln->tn_op == INDIR && ln->tn_left->tn_op == PLUS) 4493 /* check the range of array indices */ 4494 check_array_index(ln->tn_left, true); 4495 } 4496 4497 static void 4498 check_expr_load(const tnode_t *ln) 4499 { 4500 if (ln->tn_op == INDIR && ln->tn_left->tn_op == PLUS) 4501 /* check the range of array indices */ 4502 check_array_index(ln->tn_left, false); 4503 } 4504 4505 /* 4506 * If there is an asm statement in one of the compound statements around, 4507 * there may be other side effects, so don't warn. 4508 */ 4509 static bool 4510 is_asm_around(void) 4511 { 4512 for (decl_level *dl = dcs; dl != NULL; dl = dl->d_enclosing) 4513 if (dl->d_asm) 4514 return true; 4515 return false; 4516 } 4517 4518 static void 4519 check_expr_side_effect(const tnode_t *ln, bool szof) 4520 { 4521 4522 /* XXX: Taking warn_about_unreachable into account here feels wrong. */ 4523 if (ln->tn_op == NAME && (reached || !warn_about_unreachable)) { 4524 scl_t sc = ln->tn_sym->s_scl; 4525 if (sc != EXTERN && sc != STATIC && 4526 !ln->tn_sym->s_set && !szof && !is_asm_around()) { 4527 /* '%s' may be used before set */ 4528 warning(158, ln->tn_sym->s_name); 4529 mark_as_set(ln->tn_sym); 4530 } 4531 mark_as_used(ln->tn_sym, false, false); 4532 } 4533 } 4534 4535 static void 4536 check_expr_assign(const tnode_t *ln, bool szof) 4537 { 4538 /* XXX: Taking warn_about_unreachable into account here feels wrong. */ 4539 if (ln->tn_op == NAME && !szof && (reached || !warn_about_unreachable)) { 4540 mark_as_set(ln->tn_sym); 4541 if (ln->tn_sym->s_scl == EXTERN) 4542 outusg(ln->tn_sym); 4543 } 4544 if (ln->tn_op == INDIR && ln->tn_left->tn_op == PLUS) 4545 /* check the range of array indices */ 4546 check_array_index(ln->tn_left, false); 4547 } 4548 4549 static void 4550 check_expr_call(const tnode_t *tn, const tnode_t *ln, 4551 bool szof, bool vctx, bool cond, bool retval_discarded) 4552 { 4553 lint_assert(ln->tn_op == ADDR); 4554 lint_assert(ln->tn_left->tn_op == NAME); 4555 if (!szof && !is_compiler_builtin(ln->tn_left->tn_sym->s_name)) 4556 outcall(tn, vctx || cond, retval_discarded); 4557 } 4558 4559 static bool 4560 check_expr_op(const tnode_t *tn, op_t op, const tnode_t *ln, 4561 bool szof, bool fcall, bool vctx, bool cond, 4562 bool retval_discarded, bool eqwarn) 4563 { 4564 switch (op) { 4565 case ADDR: 4566 check_expr_addr(ln, szof, fcall); 4567 break; 4568 case LOAD: 4569 check_expr_load(ln); 4570 /* FALLTHROUGH */ 4571 case PUSH: 4572 case INCBEF: 4573 case DECBEF: 4574 case INCAFT: 4575 case DECAFT: 4576 case ADDASS: 4577 case SUBASS: 4578 case MULASS: 4579 case DIVASS: 4580 case MODASS: 4581 case ANDASS: 4582 case ORASS: 4583 case XORASS: 4584 case SHLASS: 4585 case SHRASS: 4586 case REAL: 4587 case IMAG: 4588 check_expr_side_effect(ln, szof); 4589 break; 4590 case ASSIGN: 4591 check_expr_assign(ln, szof); 4592 break; 4593 case CALL: 4594 check_expr_call(tn, ln, szof, vctx, cond, retval_discarded); 4595 break; 4596 case EQ: 4597 if (hflag && eqwarn) 4598 /* operator '==' found where '=' was expected */ 4599 warning(160); 4600 break; 4601 case CON: 4602 case NAME: 4603 case STRING: 4604 return false; 4605 default: 4606 break; 4607 } 4608 return true; 4609 } 4610 4611 /* 4612 * vctx ??? 4613 * cond whether the expression is a condition that 4614 * will be compared with 0 4615 * eqwarn whether the operator '==' might be a 4616 * misspelled '=' 4617 * fcall whether the expression is a function call 4618 * retval_discarded whether the return value of a function call 4619 * is discarded; such calls will be analyzed by 4620 * lint2 in messages 4, 8 and 9 4621 * szof whether the expression is part of a sizeof 4622 * expression, which means that its value is 4623 * discarded since only the type is relevant 4624 */ 4625 void 4626 check_expr_misc(const tnode_t *tn, bool vctx, bool cond, 4627 bool eqwarn, bool fcall, bool retval_discarded, bool szof) 4628 { 4629 4630 if (tn == NULL) 4631 return; 4632 4633 tnode_t *ln = tn->tn_left; 4634 tnode_t *rn = tn->tn_right; 4635 op_t op = tn->tn_op; 4636 const mod_t *mp = &modtab[op]; 4637 4638 if (!check_expr_op(tn, op, ln, 4639 szof, fcall, vctx, cond, retval_discarded, eqwarn)) 4640 return; 4641 4642 bool cvctx = mp->m_value_context; 4643 bool ccond = mp->m_compares_with_zero; 4644 bool eq = mp->m_warn_if_operand_eq && 4645 !ln->tn_parenthesized && 4646 rn != NULL && !rn->tn_parenthesized; 4647 4648 /* 4649 * values of operands of ':' are not used if the type of at least 4650 * one of the operands (for gcc compatibility) is void 4651 * XXX test/value context of QUEST should probably be used as 4652 * context for both operands of COLON 4653 */ 4654 if (op == COLON && tn->tn_type->t_tspec == VOID) 4655 cvctx = ccond = false; 4656 bool discard = op == CVT && tn->tn_type->t_tspec == VOID; 4657 check_expr_misc(ln, cvctx, ccond, eq, op == CALL, discard, szof); 4658 4659 switch (op) { 4660 case PUSH: 4661 if (rn != NULL) 4662 check_expr_misc(rn, false, false, eq, false, false, 4663 szof); 4664 break; 4665 case LOGAND: 4666 case LOGOR: 4667 check_expr_misc(rn, false, true, eq, false, false, szof); 4668 break; 4669 case COLON: 4670 check_expr_misc(rn, cvctx, ccond, eq, false, false, szof); 4671 break; 4672 case COMMA: 4673 check_expr_misc(rn, vctx, cond, false, false, false, szof); 4674 break; 4675 default: 4676 if (mp->m_binary) 4677 check_expr_misc(rn, true, false, eq, false, false, 4678 szof); 4679 break; 4680 } 4681 } 4682 4683 /* 4684 * Return whether the expression can be used for static initialization. 4685 * 4686 * Constant initialization expressions must be constant or an address 4687 * of a static object with an optional offset. In the first case, 4688 * the result is returned in *offsp. In the second case, the static 4689 * object is returned in *symp and the offset in *offsp. 4690 * 4691 * The expression can consist of PLUS, MINUS, ADDR, NAME, STRING and 4692 * CON. Type conversions are allowed if they do not change binary 4693 * representation (including width). 4694 * 4695 * C99 6.6 "Constant expressions" 4696 * C99 6.7.8p4 restricts initializers for static storage duration 4697 */ 4698 bool 4699 constant_addr(const tnode_t *tn, const sym_t **symp, ptrdiff_t *offsp) 4700 { 4701 const sym_t *sym; 4702 ptrdiff_t offs1, offs2; 4703 tspec_t t, ot; 4704 4705 switch (tn->tn_op) { 4706 case MINUS: 4707 if (tn->tn_right->tn_op == CVT) 4708 return constant_addr(tn->tn_right, symp, offsp); 4709 else if (tn->tn_right->tn_op != CON) 4710 return false; 4711 /* FALLTHROUGH */ 4712 case PLUS: 4713 offs1 = offs2 = 0; 4714 if (tn->tn_left->tn_op == CON) { 4715 offs1 = (ptrdiff_t)tn->tn_left->tn_val.u.integer; 4716 if (!constant_addr(tn->tn_right, &sym, &offs2)) 4717 return false; 4718 } else if (tn->tn_right->tn_op == CON) { 4719 offs2 = (ptrdiff_t)tn->tn_right->tn_val.u.integer; 4720 if (tn->tn_op == MINUS) 4721 offs2 = -offs2; 4722 if (!constant_addr(tn->tn_left, &sym, &offs1)) 4723 return false; 4724 } else { 4725 return false; 4726 } 4727 *symp = sym; 4728 *offsp = offs1 + offs2; 4729 return true; 4730 case ADDR: 4731 if (tn->tn_left->tn_op == NAME) { 4732 *symp = tn->tn_left->tn_sym; 4733 *offsp = 0; 4734 return true; 4735 } else { 4736 /* 4737 * If this were the front end of a compiler, we 4738 * would return a label instead of 0, at least if 4739 * 'tn->tn_left->tn_op == STRING'. 4740 */ 4741 *symp = NULL; 4742 *offsp = 0; 4743 return true; 4744 } 4745 case CVT: 4746 t = tn->tn_type->t_tspec; 4747 ot = tn->tn_left->tn_type->t_tspec; 4748 if ((!is_integer(t) && t != PTR) || 4749 (!is_integer(ot) && ot != PTR)) { 4750 return false; 4751 } 4752 #if 0 4753 /* 4754 * consider: 4755 * struct foo { 4756 * unsigned char a; 4757 * } f = { 4758 * (unsigned char)(unsigned long) 4759 * (&(((struct foo *)0)->a)) 4760 * }; 4761 * since psize(unsigned long) != psize(unsigned char), 4762 * this fails. 4763 */ 4764 else if (psize(t) != psize(ot)) 4765 return -1; 4766 #endif 4767 return constant_addr(tn->tn_left, symp, offsp); 4768 default: 4769 return false; 4770 } 4771 } 4772 4773 /* Append s2 to s1, then free s2. */ 4774 strg_t * 4775 cat_strings(strg_t *s1, strg_t *s2) 4776 { 4777 4778 if (s1->st_char != s2->st_char) { 4779 /* cannot concatenate wide and regular string literals */ 4780 error(292); 4781 return s1; 4782 } 4783 4784 size_t len1 = s1->st_len; 4785 size_t len2 = s2->st_len; 4786 size_t chsize = s1->st_char ? sizeof(char) : sizeof(wchar_t); 4787 size_t size1 = len1 * chsize; 4788 size_t size2 = (len2 + 1) * chsize; 4789 s1->st_mem = xrealloc(s1->st_mem, size1 + size2); 4790 memcpy((char *)s1->st_mem + size1, s2->st_mem, size2); 4791 free(s2->st_mem); 4792 4793 s1->st_len = len1 + len2; 4794 free(s2); 4795 4796 return s1; 4797 } 4798 4799 4800 typedef struct stmt_expr { 4801 memory_pool se_mem; 4802 sym_t *se_sym; 4803 struct stmt_expr *se_enclosing; 4804 } stmt_expr; 4805 4806 static stmt_expr *stmt_exprs; 4807 4808 void 4809 begin_statement_expr(void) 4810 { 4811 stmt_expr *se = xmalloc(sizeof(*se)); 4812 se->se_mem = expr_save_memory(); 4813 se->se_sym = NULL; 4814 se->se_enclosing = stmt_exprs; 4815 stmt_exprs = se; 4816 } 4817 4818 void 4819 do_statement_expr(tnode_t *tn) 4820 { 4821 block_level--; 4822 mem_block_level--; 4823 stmt_exprs->se_sym = tn != NULL 4824 ? mktempsym(block_dup_type(tn->tn_type)) 4825 : NULL; /* after a syntax error */ 4826 mem_block_level++; 4827 block_level++; 4828 /* ({ }) is a GCC extension */ 4829 gnuism(320); 4830 } 4831 4832 tnode_t * 4833 end_statement_expr(void) 4834 { 4835 stmt_expr *se = stmt_exprs; 4836 if (se->se_sym == NULL) 4837 return NULL; /* after a syntax error */ 4838 tnode_t *tn = build_name(se->se_sym, false); 4839 (void)expr_save_memory(); /* leak */ 4840 expr_restore_memory(se->se_mem); 4841 stmt_exprs = se->se_enclosing; 4842 free(se); 4843 return tn; 4844 } 4845
Indexes created Tue Sep 23 14:10:03 GMT 2025