tree.c revision 1.549
1 /* $NetBSD: tree.c,v 1.549 2023/07/07 20:19:08 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 1.549 2023/07/07 20:19:08 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 && hflag && allow_trad && allow_c90 1352 && portable_size_in_bits(lt) < portable_size_in_bits(rt)) 1353 /* semantics of '%s' change in ANSI C; ... */ 1354 warning(118, "<<="); 1355 1356 if (op != SHLASS && op != SHRASS 1357 && (op == ASSIGN || lt != PTR) 1358 && (lt != rt || (ln->tn_type->t_bitfield && rn->tn_op == CON))) { 1359 rn = convert(op, 0, ln->tn_type, rn); 1360 rt = lt; 1361 } 1362 1363 if (any_query_enabled && rn->tn_op == CVT && rn->tn_cast && 1364 types_compatible(ln->tn_type, rn->tn_type, false, false, NULL) && 1365 is_cast_redundant(rn)) { 1366 /* redundant cast from '%s' to '%s' before assignment */ 1367 query_message(7, 1368 type_name(rn->tn_left->tn_type), type_name(rn->tn_type)); 1369 } 1370 1371 return new_tnode(op, sys, ln->tn_type, ln, rn); 1372 } 1373 1374 /* 1375 * Create a node for REAL, IMAG 1376 */ 1377 static tnode_t * 1378 build_real_imag(op_t op, bool sys, tnode_t *ln) 1379 { 1380 1381 lint_assert(ln != NULL); 1382 if (ln->tn_op == NAME) { 1383 /* 1384 * This may be too much, but it avoids wrong warnings. 1385 * See d_c99_complex_split.c. 1386 */ 1387 mark_as_used(ln->tn_sym, false, false); 1388 mark_as_set(ln->tn_sym); 1389 } 1390 1391 tnode_t *cn; 1392 switch (ln->tn_type->t_tspec) { 1393 case LCOMPLEX: 1394 /* XXX: integer and LDOUBLE don't match. */ 1395 cn = build_integer_constant(LDOUBLE, (int64_t)1); 1396 break; 1397 case DCOMPLEX: 1398 /* XXX: integer and DOUBLE don't match. */ 1399 cn = build_integer_constant(DOUBLE, (int64_t)1); 1400 break; 1401 case FCOMPLEX: 1402 /* XXX: integer and FLOAT don't match. */ 1403 cn = build_integer_constant(FLOAT, (int64_t)1); 1404 break; 1405 default: 1406 /* '__%s__' is illegal for type '%s' */ 1407 error(276, op == REAL ? "real" : "imag", 1408 type_name(ln->tn_type)); 1409 return NULL; 1410 } 1411 1412 tnode_t *ntn = new_tnode(op, sys, cn->tn_type, ln, cn); 1413 ntn->tn_lvalue = true; 1414 return ntn; 1415 } 1416 1417 static bool 1418 is_confusing_precedence(op_t op, op_t lop, bool lparen, op_t rop, bool rparen) 1419 { 1420 1421 if (op == SHL || op == SHR) { 1422 if (!lparen && (lop == PLUS || lop == MINUS)) 1423 return true; 1424 if (!rparen && (rop == PLUS || rop == MINUS)) 1425 return true; 1426 return false; 1427 } 1428 1429 if (op == LOGOR) { 1430 if (!lparen && lop == LOGAND) 1431 return true; 1432 if (!rparen && rop == LOGAND) 1433 return true; 1434 return false; 1435 } 1436 1437 lint_assert(op == BITAND || op == BITXOR || op == BITOR); 1438 if (!lparen && lop != op) { 1439 if (lop == PLUS || lop == MINUS) 1440 return true; 1441 if (lop == BITAND || lop == BITXOR) 1442 return true; 1443 } 1444 if (!rparen && rop != op) { 1445 if (rop == PLUS || rop == MINUS) 1446 return true; 1447 if (rop == BITAND || rop == BITXOR) 1448 return true; 1449 } 1450 return false; 1451 } 1452 1453 /* 1454 * Print a warning if the given node has operands which should be 1455 * parenthesized. 1456 * 1457 * XXX Does not work if an operand is a constant expression. Constant 1458 * expressions are already folded. 1459 */ 1460 static void 1461 check_precedence_confusion(tnode_t *tn) 1462 { 1463 tnode_t *ln, *rn; 1464 1465 if (!hflag) 1466 return; 1467 1468 debug_node(tn); 1469 1470 lint_assert(is_binary(tn)); 1471 for (ln = tn->tn_left; ln->tn_op == CVT; ln = ln->tn_left) 1472 continue; 1473 for (rn = tn->tn_right; rn->tn_op == CVT; rn = rn->tn_left) 1474 continue; 1475 1476 if (is_confusing_precedence(tn->tn_op, 1477 ln->tn_op, ln->tn_parenthesized, 1478 rn->tn_op, rn->tn_parenthesized)) { 1479 /* precedence confusion possible: parenthesize! */ 1480 warning(169); 1481 } 1482 } 1483 1484 /* 1485 * Fold constant nodes, as much as is needed for comparing the value with 0. 1486 */ 1487 static tnode_t * 1488 fold_bool(tnode_t *tn) 1489 { 1490 1491 val_t *v = xcalloc(1, sizeof(*v)); 1492 v->v_tspec = tn->tn_type->t_tspec; 1493 lint_assert(v->v_tspec == INT || (Tflag && v->v_tspec == BOOL)); 1494 1495 bool l = constant_is_nonzero(tn->tn_left); 1496 bool r = is_binary(tn) && constant_is_nonzero(tn->tn_right); 1497 1498 switch (tn->tn_op) { 1499 case NOT: 1500 if (hflag && !constcond_flag) 1501 /* constant argument to '!' */ 1502 warning(239); 1503 v->u.integer = !l ? 1 : 0; 1504 break; 1505 case LOGAND: 1506 v->u.integer = l && r ? 1 : 0; 1507 break; 1508 case LOGOR: 1509 v->u.integer = l || r ? 1 : 0; 1510 break; 1511 default: 1512 lint_assert(/*CONSTCOND*/false); 1513 } 1514 1515 return build_constant(tn->tn_type, v); 1516 } 1517 1518 static long double 1519 floating_error_value(tspec_t t, long double lv) 1520 { 1521 if (t == FLOAT) 1522 return lv < 0 ? -FLT_MAX : FLT_MAX; 1523 if (t == DOUBLE) 1524 return lv < 0 ? -DBL_MAX : DBL_MAX; 1525 /* 1526 * When NetBSD is cross-built in MKLINT=yes mode on x86_64 for 1527 * sparc64, tools/lint checks this code while building usr.bin/xlint. 1528 * In that situation, lint uses the preprocessor for sparc64, in which 1529 * the type 'long double' is IEEE-754-binary128, affecting the macro 1530 * LDBL_MAX below. The type 'long double', as well as the strtold 1531 * implementation, comes from the host platform x86_64 though, where 1532 * 'long double' consumes 128 bits as well but only uses 80 of them. 1533 * The exponent range of the two 'long double' types is the same, but 1534 * the maximum finite value differs due to the extended precision on 1535 * sparc64. 1536 * 1537 * To properly handle the data types of the target platform, lint 1538 * would have to implement the floating-point types in a 1539 * platform-independent way, which is not worth the effort, given how 1540 * few programs practically use 'long double'. 1541 */ 1542 /* LINTED 248: floating-point constant out of range */ 1543 long double max = LDBL_MAX; 1544 return lv < 0 ? -max : max; 1545 } 1546 1547 static bool 1548 is_floating_overflow(tspec_t t, long double val) 1549 { 1550 if (fpe != 0 || isfinite(val) == 0) 1551 return true; 1552 if (t == FLOAT && (val > FLT_MAX || val < -FLT_MAX)) 1553 return true; 1554 if (t == DOUBLE && (val > DBL_MAX || val < -DBL_MAX)) 1555 return true; 1556 return false; 1557 } 1558 1559 /* 1560 * Fold constant nodes having operands with floating point type. 1561 */ 1562 static tnode_t * 1563 fold_float(tnode_t *tn) 1564 { 1565 1566 fpe = 0; 1567 1568 tspec_t t = tn->tn_type->t_tspec; 1569 1570 val_t *v = xcalloc(1, sizeof(*v)); 1571 v->v_tspec = t; 1572 1573 lint_assert(is_floating(t)); 1574 lint_assert(t == tn->tn_left->tn_type->t_tspec); 1575 lint_assert(!is_binary(tn) || t == tn->tn_right->tn_type->t_tspec); 1576 1577 long double lv = tn->tn_left->tn_val.u.floating; 1578 long double rv = is_binary(tn) ? tn->tn_right->tn_val.u.floating : 0.0; 1579 1580 switch (tn->tn_op) { 1581 case UPLUS: 1582 v->u.floating = lv; 1583 break; 1584 case UMINUS: 1585 v->u.floating = -lv; 1586 break; 1587 case MULT: 1588 v->u.floating = lv * rv; 1589 break; 1590 case DIV: 1591 if (rv == 0.0) { 1592 /* division by 0 */ 1593 error(139); 1594 v->u.floating = floating_error_value(t, lv); 1595 } else { 1596 v->u.floating = lv / rv; 1597 } 1598 break; 1599 case PLUS: 1600 v->u.floating = lv + rv; 1601 break; 1602 case MINUS: 1603 v->u.floating = lv - rv; 1604 break; 1605 case LT: 1606 v->u.integer = lv < rv ? 1 : 0; 1607 break; 1608 case LE: 1609 v->u.integer = lv <= rv ? 1 : 0; 1610 break; 1611 case GE: 1612 v->u.integer = lv >= rv ? 1 : 0; 1613 break; 1614 case GT: 1615 v->u.integer = lv > rv ? 1 : 0; 1616 break; 1617 case EQ: 1618 v->u.integer = lv == rv ? 1 : 0; 1619 break; 1620 case NE: 1621 v->u.integer = lv != rv ? 1 : 0; 1622 break; 1623 default: 1624 lint_assert(/*CONSTCOND*/false); 1625 } 1626 1627 lint_assert(fpe != 0 || isnan(v->u.floating) == 0); 1628 if (is_complex(v->v_tspec)) { 1629 /* 1630 * Don't warn, as lint doesn't model the imaginary part of 1631 * complex numbers. 1632 */ 1633 fpe = 0; 1634 } else if (is_floating_overflow(t, v->u.floating)) { 1635 /* floating point overflow on operator '%s' */ 1636 warning(142, op_name(tn->tn_op)); 1637 v->u.floating = floating_error_value(t, v->u.floating); 1638 fpe = 0; 1639 } 1640 1641 return build_constant(tn->tn_type, v); 1642 } 1643 1644 /* 1645 * Create a tree node for a binary operator and its two operands. Also called 1646 * for unary operators; in that case rn is NULL. 1647 * 1648 * Function calls, sizeof and casts are handled elsewhere. 1649 */ 1650 tnode_t * 1651 build_binary(tnode_t *ln, op_t op, bool sys, tnode_t *rn) 1652 { 1653 const mod_t *mp = &modtab[op]; 1654 1655 /* If there was an error in one of the operands, return. */ 1656 if (ln == NULL || (mp->m_binary && rn == NULL)) 1657 return NULL; 1658 1659 /* 1660 * Apply class conversions to the left operand, but only if its 1661 * value is needed or compared with zero. 1662 */ 1663 if (mp->m_value_context || mp->m_compares_with_zero) 1664 ln = cconv(ln); 1665 /* 1666 * The right operand is almost always in a test or value context, 1667 * except if it is a struct or union member. 1668 */ 1669 if (mp->m_binary && op != ARROW && op != POINT) 1670 rn = cconv(rn); 1671 1672 /* 1673 * Print some warnings for comparisons of unsigned values with 1674 * constants lower than or equal to null. This must be done 1675 * before promote() because otherwise unsigned char and unsigned 1676 * short would be promoted to int. Types are also tested to be 1677 * CHAR, which would also become int. 1678 */ 1679 if (mp->m_comparison) 1680 check_integer_comparison(op, ln, rn); 1681 1682 if (mp->m_value_context || mp->m_compares_with_zero) 1683 ln = promote(op, false, ln); 1684 if (mp->m_binary && op != ARROW && op != POINT && 1685 op != ASSIGN && op != RETURN && op != INIT) { 1686 rn = promote(op, false, rn); 1687 } 1688 1689 /* 1690 * If the result of the operation is different for signed or 1691 * unsigned operands and one of the operands is signed only in 1692 * ANSI C, print a warning. 1693 */ 1694 if (mp->m_warn_if_left_unsigned_in_c90 && 1695 ln->tn_op == CON && ln->tn_val.v_unsigned_since_c90) { 1696 /* ANSI C treats constant as unsigned, op '%s' */ 1697 warning(218, mp->m_name); 1698 ln->tn_val.v_unsigned_since_c90 = false; 1699 } 1700 if (mp->m_warn_if_right_unsigned_in_c90 && 1701 rn->tn_op == CON && rn->tn_val.v_unsigned_since_c90) { 1702 /* ANSI C treats constant as unsigned, op '%s' */ 1703 warning(218, mp->m_name); 1704 rn->tn_val.v_unsigned_since_c90 = false; 1705 } 1706 1707 /* Make sure both operands are of the same type */ 1708 if (mp->m_balance_operands || (!allow_c90 && (op == SHL || op == SHR))) 1709 balance(op, &ln, &rn); 1710 1711 /* 1712 * Check types for compatibility with the operation and mutual 1713 * compatibility. Return if there are serious problems. 1714 */ 1715 if (!typeok(op, 0, ln, rn)) 1716 return NULL; 1717 1718 /* And now create the node. */ 1719 tnode_t *ntn; 1720 switch (op) { 1721 case POINT: 1722 case ARROW: 1723 ntn = build_struct_access(op, sys, ln, rn); 1724 break; 1725 case INCAFT: 1726 case DECAFT: 1727 case INCBEF: 1728 case DECBEF: 1729 ntn = build_prepost_incdec(op, sys, ln); 1730 break; 1731 case ADDR: 1732 ntn = build_address(sys, ln, false); 1733 break; 1734 case INDIR: 1735 ntn = new_tnode(INDIR, sys, ln->tn_type->t_subt, ln, NULL); 1736 break; 1737 case PLUS: 1738 case MINUS: 1739 ntn = build_plus_minus(op, sys, ln, rn); 1740 break; 1741 case SHL: 1742 case SHR: 1743 ntn = build_bit_shift(op, sys, ln, rn); 1744 break; 1745 case COLON: 1746 ntn = build_colon(sys, ln, rn); 1747 break; 1748 case ASSIGN: 1749 case MULASS: 1750 case DIVASS: 1751 case MODASS: 1752 case ADDASS: 1753 case SUBASS: 1754 case SHLASS: 1755 case SHRASS: 1756 case ANDASS: 1757 case XORASS: 1758 case ORASS: 1759 case RETURN: 1760 case INIT: 1761 ntn = build_assignment(op, sys, ln, rn); 1762 break; 1763 case COMMA: 1764 if (any_query_enabled) { 1765 /* comma operator with types '%s' and '%s' */ 1766 query_message(12, 1767 type_name(ln->tn_type), type_name(rn->tn_type)); 1768 } 1769 /* FALLTHROUGH */ 1770 case QUEST: 1771 ntn = new_tnode(op, sys, rn->tn_type, ln, rn); 1772 break; 1773 case REAL: 1774 case IMAG: 1775 ntn = build_real_imag(op, sys, ln); 1776 break; 1777 default: 1778 lint_assert(mp->m_binary == (rn != NULL)); 1779 type_t *rettp = mp->m_returns_bool 1780 ? gettyp(Tflag ? BOOL : INT) : ln->tn_type; 1781 ntn = new_tnode(op, sys, rettp, ln, rn); 1782 break; 1783 } 1784 1785 /* Return if an error occurred. */ 1786 if (ntn == NULL) 1787 return NULL; 1788 1789 /* Print a warning if precedence confusion is possible */ 1790 if (mp->m_possible_precedence_confusion) 1791 check_precedence_confusion(ntn); 1792 1793 /* 1794 * Print a warning if one of the operands is in a context where 1795 * it is compared with zero and if this operand is a constant. 1796 */ 1797 if (hflag && !constcond_flag && 1798 mp->m_compares_with_zero && 1799 (ln->tn_op == CON || 1800 ((mp->m_binary && op != QUEST) && rn->tn_op == CON)) && 1801 /* XXX: rn->tn_system_dependent should be checked as well */ 1802 !ln->tn_system_dependent) { 1803 /* constant in conditional context */ 1804 warning(161); 1805 } 1806 1807 /* Fold if the operator requires it */ 1808 if (mp->m_fold_constant_operands) { 1809 if (ln->tn_op == CON && (!mp->m_binary || rn->tn_op == CON)) { 1810 if (mp->m_compares_with_zero) { 1811 ntn = fold_bool(ntn); 1812 } else if (is_floating(ntn->tn_type->t_tspec)) { 1813 ntn = fold_float(ntn); 1814 } else { 1815 ntn = fold(ntn); 1816 } 1817 } else if (op == QUEST && ln->tn_op == CON) { 1818 ntn = ln->tn_val.u.integer != 0 1819 ? rn->tn_left : rn->tn_right; 1820 } 1821 } 1822 1823 return ntn; 1824 } 1825 1826 tnode_t * 1827 build_unary(op_t op, bool sys, tnode_t *tn) 1828 { 1829 return build_binary(tn, op, sys, NULL); 1830 } 1831 1832 static bool 1833 are_members_compatible(const sym_t *a, const sym_t *b) 1834 { 1835 if (a->u.s_member.sm_offset_in_bits != b->u.s_member.sm_offset_in_bits) 1836 return false; 1837 1838 const type_t *atp = a->s_type; 1839 const type_t *btp = b->s_type; 1840 bool w = false; 1841 if (!types_compatible(atp, btp, false, false, &w) && !w) 1842 return false; 1843 if (a->s_bitfield != b->s_bitfield) 1844 return false; 1845 if (a->s_bitfield) { 1846 if (atp->t_bit_field_width != btp->t_bit_field_width) 1847 return false; 1848 if (atp->t_bit_field_offset != btp->t_bit_field_offset) 1849 return false; 1850 } 1851 return true; 1852 } 1853 1854 /* 1855 * Return whether all struct/union members with the same name have the same 1856 * type and offset. 1857 */ 1858 static bool 1859 all_members_compatible(const sym_t *msym) 1860 { 1861 for (const sym_t *csym = msym; 1862 csym != NULL; csym = csym->s_symtab_next) { 1863 if (!is_member(csym)) 1864 continue; 1865 if (strcmp(msym->s_name, csym->s_name) != 0) 1866 continue; 1867 1868 for (const sym_t *sym = csym->s_symtab_next; 1869 sym != NULL; sym = sym->s_symtab_next) { 1870 if (is_member(sym) 1871 && strcmp(csym->s_name, sym->s_name) == 0 1872 && !are_members_compatible(csym, sym)) 1873 return false; 1874 } 1875 } 1876 return true; 1877 } 1878 1879 sym_t * 1880 find_member(const type_t *tp, const char *name) 1881 { 1882 for (sym_t *mem = tp->t_sou->sou_first_member; 1883 mem != NULL; mem = mem->s_next) { 1884 if (strcmp(mem->s_name, name) == 0) 1885 return mem; 1886 } 1887 for (sym_t *mem = tp->t_sou->sou_first_member; 1888 mem != NULL; mem = mem->s_next) { 1889 if (is_struct_or_union(mem->s_type->t_tspec) && 1890 mem->s_name == unnamed) { 1891 sym_t *nested_mem = find_member(mem->s_type, name); 1892 if (nested_mem != NULL) 1893 return nested_mem; 1894 } 1895 } 1896 return NULL; 1897 } 1898 1899 /* 1900 * Returns a symbol which has the same name as the msym argument and is a 1901 * member of the struct or union specified by the tn argument. 1902 */ 1903 static sym_t * 1904 struct_or_union_member(tnode_t *tn, op_t op, sym_t *msym) 1905 { 1906 1907 /* 1908 * Remove the member if it was unknown until now, which means 1909 * that no defined struct or union has a member with the same name. 1910 */ 1911 if (msym->s_scl == NOSCL) { 1912 /* type '%s' does not have member '%s' */ 1913 error(101, type_name(tn->tn_type), msym->s_name); 1914 rmsym(msym); 1915 msym->s_kind = FMEMBER; 1916 msym->s_scl = STRUCT_MEMBER; 1917 1918 struct_or_union *sou = expr_zero_alloc(sizeof(*sou)); 1919 sou->sou_tag = expr_zero_alloc(sizeof(*sou->sou_tag)); 1920 sou->sou_tag->s_name = unnamed; 1921 1922 msym->u.s_member.sm_containing_type = sou; 1923 /* 1924 * The member sm_offset_in_bits is not needed here since this 1925 * symbol can only be used for error reporting. 1926 */ 1927 return msym; 1928 } 1929 1930 /* Determine the tag type of which msym is expected to be a member. */ 1931 const type_t *tp = NULL; 1932 if (op == POINT && is_struct_or_union(tn->tn_type->t_tspec)) 1933 tp = tn->tn_type; 1934 if (op == ARROW && tn->tn_type->t_tspec == PTR 1935 && is_struct_or_union(tn->tn_type->t_subt->t_tspec)) 1936 tp = tn->tn_type->t_subt; 1937 struct_or_union *sou = tp != NULL ? tp->t_sou : NULL; 1938 1939 /* 1940 * If this struct/union has a member with the name of msym, return it. 1941 */ 1942 if (sou != NULL) { 1943 for (sym_t *sym = msym; 1944 sym != NULL; sym = sym->s_symtab_next) { 1945 if (is_member(sym) && 1946 sym->u.s_member.sm_containing_type == sou && 1947 strcmp(sym->s_name, msym->s_name) == 0) 1948 return sym; 1949 } 1950 } 1951 1952 if (tp != NULL) { 1953 sym_t *nested_mem = find_member(tp, msym->s_name); 1954 if (nested_mem != NULL) 1955 return nested_mem; 1956 } 1957 1958 bool eq = all_members_compatible(msym); 1959 1960 /* 1961 * Now handle the case in which the left operand refers really 1962 * to a struct/union, but the right operand is not member of it. 1963 */ 1964 if (sou != NULL) { 1965 if (eq && !allow_c90) { 1966 /* illegal use of member '%s' */ 1967 warning(102, msym->s_name); 1968 } else { 1969 /* illegal use of member '%s' */ 1970 error(102, msym->s_name); 1971 } 1972 return msym; 1973 } 1974 1975 /* 1976 * Now the left operand of ARROW does not point to a struct/union 1977 * or the left operand of POINT is no struct/union. 1978 */ 1979 if (eq) { 1980 if (op == POINT) { 1981 if (!allow_c90) { 1982 /* left operand of '.' must be struct ... */ 1983 warning(103, type_name(tn->tn_type)); 1984 } else { 1985 /* left operand of '.' must be struct ... */ 1986 error(103, type_name(tn->tn_type)); 1987 } 1988 } else { 1989 if (!allow_c90 && tn->tn_type->t_tspec == PTR) { 1990 /* left operand of '->' must be pointer ... */ 1991 warning(104, type_name(tn->tn_type)); 1992 } else { 1993 /* left operand of '->' must be pointer ... */ 1994 error(104, type_name(tn->tn_type)); 1995 } 1996 } 1997 } else { 1998 if (!allow_c90) { 1999 /* non-unique member requires struct/union %s */ 2000 error(105, op == POINT ? "object" : "pointer"); 2001 } else { 2002 /* unacceptable operand of '%s' */ 2003 error(111, op_name(op)); 2004 } 2005 } 2006 2007 return msym; 2008 } 2009 2010 tnode_t * 2011 build_member_access(tnode_t *ln, op_t op, bool sys, sbuf_t *member) 2012 { 2013 sym_t *msym; 2014 2015 if (ln == NULL) 2016 return NULL; 2017 2018 if (op == ARROW) { 2019 /* must do this before struct_or_union_member is called */ 2020 ln = cconv(ln); 2021 } 2022 msym = struct_or_union_member(ln, op, getsym(member)); 2023 return build_binary(ln, op, sys, build_name(msym, false)); 2024 } 2025 2026 /* 2027 * Perform class conversions. 2028 * 2029 * Arrays of type T are converted into pointers to type T. 2030 * Functions are converted to pointers to functions. 2031 * Lvalues are converted to rvalues. 2032 * 2033 * C99 6.3 "Conversions" 2034 * C99 6.3.2 "Other operands" 2035 * C99 6.3.2.1 "Lvalues, arrays, and function designators" 2036 */ 2037 tnode_t * 2038 cconv(tnode_t *tn) 2039 { 2040 /* 2041 * Array-lvalue (array of type T) is converted into rvalue 2042 * (pointer to type T) 2043 */ 2044 if (tn->tn_type->t_tspec == ARRAY) { 2045 if (!tn->tn_lvalue) { 2046 /* XXX print correct operator */ 2047 /* %soperand of '%s' must be lvalue */ 2048 gnuism(114, "", op_name(ADDR)); 2049 } 2050 tn = new_tnode(ADDR, tn->tn_sys, 2051 expr_derive_type(tn->tn_type->t_subt, PTR), tn, NULL); 2052 } 2053 2054 /* 2055 * Expression of type function (function with return value of type T) 2056 * in rvalue-expression (pointer to function with return value 2057 * of type T) 2058 */ 2059 if (tn->tn_type->t_tspec == FUNC) 2060 tn = build_address(tn->tn_sys, tn, true); 2061 2062 /* lvalue to rvalue */ 2063 if (tn->tn_lvalue) { 2064 type_t *tp = expr_dup_type(tn->tn_type); 2065 /* C99 6.3.2.1p2 sentence 2 says to remove the qualifiers. */ 2066 tp->t_const = tp->t_volatile = false; 2067 tn = new_tnode(LOAD, tn->tn_sys, tp, tn, NULL); 2068 } 2069 2070 return tn; 2071 } 2072 2073 const tnode_t * 2074 before_conversion(const tnode_t *tn) 2075 { 2076 while (tn->tn_op == CVT && !tn->tn_cast) 2077 tn = tn->tn_left; 2078 return tn; 2079 } 2080 2081 /* 2082 * Most errors required by ANSI C are reported in struct_or_union_member(). 2083 * Here we only check for totally wrong things. 2084 */ 2085 static bool 2086 typeok_point(const tnode_t *ln, const type_t *ltp, tspec_t lt) 2087 { 2088 if (is_struct_or_union(lt)) 2089 return true; 2090 2091 if (lt == FUNC || lt == VOID || ltp->t_bitfield) 2092 goto wrong; 2093 2094 /* 2095 * Some C dialects from before C90 tolerated any lvalue on the 2096 * left-hand side of the '.' operator, allowing things like 2097 * char st[100]; st.st_mtime, assuming that the member 'st_mtime' 2098 * only occurred in a single struct; see typeok_arrow. 2099 */ 2100 if (ln->tn_lvalue) 2101 return true; 2102 2103 wrong: 2104 /* With allow_c90 we already got an error */ 2105 if (!allow_c90) 2106 /* unacceptable operand of '%s' */ 2107 error(111, op_name(POINT)); 2108 2109 return false; 2110 } 2111 2112 static bool 2113 typeok_arrow(tspec_t lt) 2114 { 2115 /* 2116 * C1978 Appendix A 14.1 says: <quote>In fact, any lvalue is allowed 2117 * before '.', and that lvalue is then assumed to have the form of 2118 * the structure of which the name of the right is a member. [...] 2119 * Such constructions are non-portable.</quote> 2120 */ 2121 if (lt == PTR || (!allow_c90 && is_integer(lt))) 2122 return true; 2123 2124 /* With allow_c90 we already got an error */ 2125 if (!allow_c90) 2126 /* unacceptable operand of '%s' */ 2127 error(111, op_name(ARROW)); 2128 return false; 2129 } 2130 2131 static bool 2132 typeok_incdec(op_t op, const tnode_t *tn, const type_t *tp) 2133 { 2134 /* operand has scalar type (checked in typeok) */ 2135 if (!tn->tn_lvalue) { 2136 if (tn->tn_op == CVT && tn->tn_cast && 2137 tn->tn_left->tn_op == LOAD) { 2138 /* a cast does not yield an lvalue */ 2139 error(163); 2140 } 2141 /* %soperand of '%s' must be lvalue */ 2142 error(114, "", op_name(op)); 2143 return false; 2144 } 2145 if (tp->t_const && allow_c90) { 2146 /* %soperand of '%s' must be modifiable lvalue */ 2147 warning(115, "", op_name(op)); 2148 } 2149 return true; 2150 } 2151 2152 static bool 2153 typeok_address(const mod_t *mp, 2154 const tnode_t *tn, const type_t *tp, tspec_t t) 2155 { 2156 if (t == ARRAY || t == FUNC) { 2157 /* ok, a warning comes later (in build_address()) */ 2158 } else if (!tn->tn_lvalue) { 2159 if (tn->tn_op == CVT && tn->tn_cast && 2160 tn->tn_left->tn_op == LOAD) { 2161 /* a cast does not yield an lvalue */ 2162 error(163); 2163 } 2164 /* %soperand of '%s' must be lvalue */ 2165 error(114, "", mp->m_name); 2166 return false; 2167 } else if (is_scalar(t)) { 2168 if (tp->t_bitfield) { 2169 /* cannot take address of bit-field */ 2170 error(112); 2171 return false; 2172 } 2173 } else if (t != STRUCT && t != UNION) { 2174 /* unacceptable operand of '%s' */ 2175 error(111, mp->m_name); 2176 return false; 2177 } 2178 if (tn->tn_op == NAME && tn->tn_sym->s_register) { 2179 /* cannot take address of register '%s' */ 2180 error(113, tn->tn_sym->s_name); 2181 return false; 2182 } 2183 return true; 2184 } 2185 2186 static bool 2187 typeok_indir(const type_t *tp, tspec_t t) 2188 { 2189 2190 if (t != PTR) { 2191 /* cannot dereference non-pointer type '%s' */ 2192 error(96, type_name(tp)); 2193 return false; 2194 } 2195 return true; 2196 } 2197 2198 static void 2199 warn_incompatible_types(op_t op, 2200 const type_t *ltp, tspec_t lt, 2201 const type_t *rtp, tspec_t rt) 2202 { 2203 const mod_t *mp = &modtab[op]; 2204 2205 if (lt == VOID || (mp->m_binary && rt == VOID)) { 2206 /* void type illegal in expression */ 2207 error(109); 2208 } else if (op == ASSIGN) { 2209 /* cannot assign to '%s' from '%s' */ 2210 error(171, type_name(ltp), type_name(rtp)); 2211 } else if (mp->m_binary) { 2212 /* operands of '%s' have incompatible types '%s' and '%s' */ 2213 error(107, mp->m_name, type_name(ltp), type_name(rtp)); 2214 } else { 2215 lint_assert(rt == NO_TSPEC); 2216 /* operand of '%s' has invalid type '%s' */ 2217 error(108, mp->m_name, type_name(ltp)); 2218 } 2219 } 2220 2221 static bool 2222 typeok_plus(op_t op, 2223 const type_t *ltp, tspec_t lt, 2224 const type_t *rtp, tspec_t rt) 2225 { 2226 /* operands have scalar types (checked in typeok) */ 2227 if ((lt == PTR && !is_integer(rt)) || (rt == PTR && !is_integer(lt))) { 2228 warn_incompatible_types(op, ltp, lt, rtp, rt); 2229 return false; 2230 } 2231 return true; 2232 } 2233 2234 static bool 2235 typeok_minus(op_t op, 2236 const type_t *ltp, tspec_t lt, 2237 const type_t *rtp, tspec_t rt) 2238 { 2239 /* operands have scalar types (checked in typeok) */ 2240 if ((lt == PTR && rt != PTR && !is_integer(rt)) || 2241 (lt != PTR && rt == PTR)) { 2242 warn_incompatible_types(op, ltp, lt, rtp, rt); 2243 return false; 2244 } 2245 if (lt == PTR && rt == PTR && 2246 !types_compatible(ltp->t_subt, rtp->t_subt, true, false, NULL)) { 2247 /* illegal pointer subtraction */ 2248 error(116); 2249 } 2250 return true; 2251 } 2252 2253 static void 2254 typeok_shr(const mod_t *mp, 2255 const tnode_t *ln, tspec_t lt, 2256 const tnode_t *rn, tspec_t rt) 2257 { 2258 tspec_t olt = before_conversion(ln)->tn_type->t_tspec; 2259 tspec_t ort = before_conversion(rn)->tn_type->t_tspec; 2260 2261 /* operands have integer types (checked in typeok) */ 2262 if (pflag && !is_uinteger(olt)) { 2263 integer_constraints lc = ic_expr(ln); 2264 if (!ic_maybe_signed(ln->tn_type, &lc)) 2265 return; 2266 2267 /* 2268 * The left operand is signed. This means that 2269 * the operation is (possibly) nonportable. 2270 */ 2271 if (ln->tn_op != CON) { 2272 /* bitwise '%s' on signed value possibly nonportable */ 2273 warning(117, mp->m_name); 2274 } else if (ln->tn_val.u.integer < 0) { 2275 /* bitwise '%s' on signed value nonportable */ 2276 warning(120, mp->m_name); 2277 } 2278 } else if (allow_trad && allow_c90 && 2279 !is_uinteger(olt) && is_uinteger(ort)) { 2280 /* The left operand would become unsigned in traditional C. */ 2281 if (hflag && (ln->tn_op != CON || ln->tn_val.u.integer < 0)) { 2282 /* semantics of '%s' change in ANSI C; use ... */ 2283 warning(118, mp->m_name); 2284 } 2285 } else if (allow_trad && allow_c90 && 2286 !is_uinteger(olt) && !is_uinteger(ort) && 2287 portable_size_in_bits(lt) < portable_size_in_bits(rt)) { 2288 /* 2289 * In traditional C the left operand would be extended 2290 * (possibly sign-extended) and then shifted. 2291 */ 2292 if (hflag && (ln->tn_op != CON || ln->tn_val.u.integer < 0)) { 2293 /* semantics of '%s' change in ANSI C; use ... */ 2294 warning(118, mp->m_name); 2295 } 2296 } 2297 } 2298 2299 static void 2300 typeok_shl(const mod_t *mp, tspec_t lt, tspec_t rt) 2301 { 2302 /* 2303 * C90 does not perform balancing for shift operations, 2304 * but traditional C does. If the width of the right operand 2305 * is greater than the width of the left operand, then in 2306 * traditional C the left operand would be extended to the 2307 * width of the right operand. For SHL this may result in 2308 * different results. 2309 */ 2310 if (portable_size_in_bits(lt) < portable_size_in_bits(rt)) { 2311 /* 2312 * XXX If both operands are constant, make sure 2313 * that there is really a difference between 2314 * ANSI C and traditional C. 2315 */ 2316 if (hflag && allow_trad && allow_c90) 2317 /* semantics of '%s' change in ANSI C; use ... */ 2318 warning(118, mp->m_name); 2319 } 2320 } 2321 2322 static void 2323 typeok_shift(const type_t *ltp, tspec_t lt, const tnode_t *rn, tspec_t rt) 2324 { 2325 if (rn->tn_op != CON) 2326 return; 2327 2328 if (!is_uinteger(rt) && rn->tn_val.u.integer < 0) { 2329 /* negative shift */ 2330 warning(121); 2331 } else if ((uint64_t)rn->tn_val.u.integer == size_in_bits(lt)) { 2332 /* shift amount %u equals bit-size of '%s' */ 2333 warning(267, (unsigned)rn->tn_val.u.integer, type_name(ltp)); 2334 } else if ((uint64_t)rn->tn_val.u.integer > size_in_bits(lt)) { 2335 /* shift amount %llu is greater than bit-size %llu of '%s' */ 2336 warning(122, (unsigned long long)rn->tn_val.u.integer, 2337 (unsigned long long)size_in_bits(lt), 2338 tspec_name(lt)); 2339 } 2340 } 2341 2342 static bool 2343 is_typeok_eq(const tnode_t *ln, tspec_t lt, const tnode_t *rn, tspec_t rt) 2344 { 2345 if (lt == PTR && is_null_pointer(rn)) 2346 return true; 2347 if (rt == PTR && is_null_pointer(ln)) 2348 return true; 2349 return false; 2350 } 2351 2352 /* 2353 * Called if incompatible pointer types are detected. 2354 * Print an appropriate warning. 2355 */ 2356 static void 2357 warn_incompatible_pointers(const mod_t *mp, 2358 const type_t *ltp, const type_t *rtp) 2359 { 2360 lint_assert(ltp->t_tspec == PTR); 2361 lint_assert(rtp->t_tspec == PTR); 2362 2363 tspec_t lt = ltp->t_subt->t_tspec; 2364 tspec_t rt = rtp->t_subt->t_tspec; 2365 2366 if (is_struct_or_union(lt) && is_struct_or_union(rt)) { 2367 if (mp == NULL) { 2368 /* illegal structure pointer combination */ 2369 warning(244); 2370 } else { 2371 /* incompatible structure pointers: '%s' '%s' '%s' */ 2372 warning(245, type_name(ltp), mp->m_name, type_name(rtp)); 2373 } 2374 } else { 2375 if (mp == NULL) { 2376 /* illegal combination of '%s' and '%s' */ 2377 warning(184, type_name(ltp), type_name(rtp)); 2378 } else { 2379 /* illegal combination of '%s' and '%s', op '%s' */ 2380 warning(124, 2381 type_name(ltp), type_name(rtp), mp->m_name); 2382 } 2383 } 2384 } 2385 2386 static void 2387 check_pointer_comparison(op_t op, const tnode_t *ln, const tnode_t *rn) 2388 { 2389 type_t *ltp = ln->tn_type, *rtp = rn->tn_type; 2390 tspec_t lst = ltp->t_subt->t_tspec, rst = rtp->t_subt->t_tspec; 2391 2392 if (lst == VOID || rst == VOID) { 2393 /* TODO: C99 behaves like C90 here. */ 2394 if ((!allow_trad && !allow_c99) && 2395 (lst == FUNC || rst == FUNC)) { 2396 /* (void *)0 is already handled in typeok() */ 2397 const char *lsts, *rsts; 2398 *(lst == FUNC ? &lsts : &rsts) = "function pointer"; 2399 *(lst == VOID ? &lsts : &rsts) = "'void *'"; 2400 /* ANSI C forbids comparison of %s with %s */ 2401 warning(274, lsts, rsts); 2402 } 2403 return; 2404 } 2405 2406 if (!types_compatible(ltp->t_subt, rtp->t_subt, true, false, NULL)) { 2407 warn_incompatible_pointers(&modtab[op], ltp, rtp); 2408 return; 2409 } 2410 2411 if (lst == FUNC && rst == FUNC) { 2412 /* TODO: C99 behaves like C90 here, see C99 6.5.8p2. */ 2413 if ((!allow_trad && !allow_c99) && op != EQ && op != NE) 2414 /* ANSI C forbids ordered comparisons of ... */ 2415 warning(125); 2416 } 2417 } 2418 2419 static bool 2420 typeok_compare(op_t op, 2421 const tnode_t *ln, const type_t *ltp, tspec_t lt, 2422 const tnode_t *rn, const type_t *rtp, tspec_t rt) 2423 { 2424 if (lt == PTR && rt == PTR) { 2425 check_pointer_comparison(op, ln, rn); 2426 return true; 2427 } 2428 2429 if (lt != PTR && rt != PTR) 2430 return true; 2431 2432 if (!is_integer(lt) && !is_integer(rt)) { 2433 warn_incompatible_types(op, ltp, lt, rtp, rt); 2434 return false; 2435 } 2436 2437 const char *lx = lt == PTR ? "pointer" : "integer"; 2438 const char *rx = rt == PTR ? "pointer" : "integer"; 2439 /* illegal combination of %s '%s' and %s '%s', op '%s' */ 2440 warning(123, lx, type_name(ltp), rx, type_name(rtp), op_name(op)); 2441 return true; 2442 } 2443 2444 static bool 2445 typeok_quest(tspec_t lt, const tnode_t *rn) 2446 { 2447 if (!is_scalar(lt)) { 2448 /* first operand must have scalar type, op ? : */ 2449 error(170); 2450 return false; 2451 } 2452 lint_assert(before_conversion(rn)->tn_op == COLON); 2453 return true; 2454 } 2455 2456 static void 2457 typeok_colon_pointer(const mod_t *mp, const type_t *ltp, const type_t *rtp) 2458 { 2459 type_t *lstp = ltp->t_subt; 2460 type_t *rstp = rtp->t_subt; 2461 tspec_t lst = lstp->t_tspec; 2462 tspec_t rst = rstp->t_tspec; 2463 2464 if ((lst == VOID && rst == FUNC) || (lst == FUNC && rst == VOID)) { 2465 /* (void *)0 is handled in typeok_colon */ 2466 /* TODO: C99 behaves like C90 here. */ 2467 if (!allow_trad && !allow_c99) 2468 /* ANSI C forbids conversion of %s to %s, op %s */ 2469 warning(305, "function pointer", "'void *'", 2470 mp->m_name); 2471 return; 2472 } 2473 2474 if (pointer_types_are_compatible(lstp, rstp, true)) 2475 return; 2476 if (!types_compatible(lstp, rstp, true, false, NULL)) 2477 warn_incompatible_pointers(mp, ltp, rtp); 2478 } 2479 2480 static bool 2481 typeok_colon(const mod_t *mp, 2482 const tnode_t *ln, const type_t *ltp, tspec_t lt, 2483 const tnode_t *rn, const type_t *rtp, tspec_t rt) 2484 { 2485 2486 if (is_arithmetic(lt) && is_arithmetic(rt)) 2487 return true; 2488 if (lt == BOOL && rt == BOOL) 2489 return true; 2490 2491 if (lt == STRUCT && rt == STRUCT && ltp->t_sou == rtp->t_sou) 2492 return true; 2493 if (lt == UNION && rt == UNION && ltp->t_sou == rtp->t_sou) 2494 return true; 2495 2496 if (lt == PTR && is_null_pointer(rn)) 2497 return true; 2498 if (rt == PTR && is_null_pointer(ln)) 2499 return true; 2500 2501 if ((lt == PTR && is_integer(rt)) || (is_integer(lt) && rt == PTR)) { 2502 const char *lx = lt == PTR ? "pointer" : "integer"; 2503 const char *rx = rt == PTR ? "pointer" : "integer"; 2504 /* illegal combination of %s '%s' and %s '%s', op '%s' */ 2505 warning(123, lx, type_name(ltp), 2506 rx, type_name(rtp), mp->m_name); 2507 return true; 2508 } 2509 2510 if (lt == VOID || rt == VOID) { 2511 if (lt != VOID || rt != VOID) 2512 /* incompatible types '%s' and '%s' in conditional */ 2513 warning(126, type_name(ltp), type_name(rtp)); 2514 return true; 2515 } 2516 2517 if (lt == PTR && rt == PTR) { 2518 typeok_colon_pointer(mp, ltp, rtp); 2519 return true; 2520 } 2521 2522 /* incompatible types '%s' and '%s' in conditional */ 2523 error(126, type_name(ltp), type_name(rtp)); 2524 return false; 2525 } 2526 2527 /* 2528 * Returns true if the given structure or union has a constant member 2529 * (maybe recursively). 2530 */ 2531 static bool 2532 has_constant_member(const type_t *tp) 2533 { 2534 lint_assert(is_struct_or_union(tp->t_tspec)); 2535 2536 for (sym_t *m = tp->t_sou->sou_first_member; 2537 m != NULL; m = m->s_next) { 2538 const type_t *mtp = m->s_type; 2539 if (mtp->t_const) 2540 return true; 2541 if (is_struct_or_union(mtp->t_tspec) && 2542 has_constant_member(mtp)) 2543 return true; 2544 } 2545 return false; 2546 } 2547 2548 static bool 2549 typeok_assign(op_t op, const tnode_t *ln, const type_t *ltp, tspec_t lt) 2550 { 2551 if (op == RETURN || op == INIT || op == FARG) 2552 return true; 2553 2554 if (!ln->tn_lvalue) { 2555 if (ln->tn_op == CVT && ln->tn_cast && 2556 ln->tn_left->tn_op == LOAD) { 2557 /* a cast does not yield an lvalue */ 2558 error(163); 2559 } 2560 /* %soperand of '%s' must be lvalue */ 2561 error(114, "left ", op_name(op)); 2562 return false; 2563 } else if (ltp->t_const 2564 || (is_struct_or_union(lt) && has_constant_member(ltp))) { 2565 if (allow_c90) 2566 /* %soperand of '%s' must be modifiable lvalue */ 2567 warning(115, "left ", op_name(op)); 2568 } 2569 return true; 2570 } 2571 2572 /* Check the types using the information from modtab[]. */ 2573 static bool 2574 typeok_scalar(op_t op, const mod_t *mp, 2575 const type_t *ltp, tspec_t lt, 2576 const type_t *rtp, tspec_t rt) 2577 { 2578 if (mp->m_takes_bool && lt == BOOL && rt == BOOL) 2579 return true; 2580 if (mp->m_requires_integer) { 2581 if (!is_integer(lt) || (mp->m_binary && !is_integer(rt))) { 2582 warn_incompatible_types(op, ltp, lt, rtp, rt); 2583 return false; 2584 } 2585 } else if (mp->m_requires_integer_or_complex) { 2586 if ((!is_integer(lt) && !is_complex(lt)) || 2587 (mp->m_binary && (!is_integer(rt) && !is_complex(rt)))) { 2588 warn_incompatible_types(op, ltp, lt, rtp, rt); 2589 return false; 2590 } 2591 } else if (mp->m_requires_scalar) { 2592 if (!is_scalar(lt) || (mp->m_binary && !is_scalar(rt))) { 2593 warn_incompatible_types(op, ltp, lt, rtp, rt); 2594 return false; 2595 } 2596 } else if (mp->m_requires_arith) { 2597 if (!is_arithmetic(lt) || 2598 (mp->m_binary && !is_arithmetic(rt))) { 2599 warn_incompatible_types(op, ltp, lt, rtp, rt); 2600 return false; 2601 } 2602 } 2603 return true; 2604 } 2605 2606 static void 2607 check_assign_void_pointer(op_t op, int arg, 2608 tspec_t lt, tspec_t lst, 2609 tspec_t rt, tspec_t rst) 2610 { 2611 2612 if (!(lt == PTR && rt == PTR && (lst == VOID || rst == VOID))) 2613 return; 2614 /* two pointers, at least one pointer to void */ 2615 2616 /* TODO: C99 behaves like C90 here. */ 2617 if (!((!allow_trad && !allow_c99) && (lst == FUNC || rst == FUNC))) 2618 return; 2619 /* comb. of ptr to func and ptr to void */ 2620 2621 const char *lts, *rts; 2622 *(lst == FUNC ? <s : &rts) = "function pointer"; 2623 *(lst == VOID ? <s : &rts) = "'void *'"; 2624 2625 switch (op) { 2626 case INIT: 2627 case RETURN: 2628 /* ANSI C forbids conversion of %s to %s */ 2629 warning(303, rts, lts); 2630 break; 2631 case FARG: 2632 /* ANSI C forbids conversion of %s to %s, arg #%d */ 2633 warning(304, rts, lts, arg); 2634 break; 2635 default: 2636 /* ANSI C forbids conversion of %s to %s, op %s */ 2637 warning(305, rts, lts, op_name(op)); 2638 break; 2639 } 2640 } 2641 2642 static bool 2643 is_direct_function_call(const tnode_t *tn, const char **out_name) 2644 { 2645 2646 if (!(tn->tn_op == CALL && 2647 tn->tn_left->tn_op == ADDR && 2648 tn->tn_left->tn_left->tn_op == NAME)) 2649 return false; 2650 2651 *out_name = tn->tn_left->tn_left->tn_sym->s_name; 2652 return true; 2653 } 2654 2655 static bool 2656 is_unconst_function(const char *name) 2657 { 2658 2659 return strcmp(name, "memchr") == 0 || 2660 strcmp(name, "strchr") == 0 || 2661 strcmp(name, "strpbrk") == 0 || 2662 strcmp(name, "strrchr") == 0 || 2663 strcmp(name, "strstr") == 0; 2664 } 2665 2666 static bool 2667 is_const_char_pointer(const tnode_t *tn) 2668 { 2669 /* 2670 * For traditional reasons, C99 6.4.5p5 defines that string literals 2671 * have type 'char[]'. They are often implicitly converted to 2672 * 'char *', for example when they are passed as function arguments. 2673 * 2674 * C99 6.4.5p6 further defines that modifying a string that is 2675 * constructed from a string literal invokes undefined behavior. 2676 * 2677 * Out of these reasons, string literals are treated as 'effectively 2678 * const' here. 2679 */ 2680 if (tn->tn_op == CVT && 2681 tn->tn_left->tn_op == ADDR && 2682 tn->tn_left->tn_left->tn_op == STRING) 2683 return true; 2684 2685 const type_t *tp = before_conversion(tn)->tn_type; 2686 return tp->t_tspec == PTR && 2687 tp->t_subt->t_tspec == CHAR && 2688 tp->t_subt->t_const; 2689 } 2690 2691 static bool 2692 is_first_arg_const_char_pointer(const tnode_t *tn) 2693 { 2694 const tnode_t *an = tn->tn_right; 2695 if (an == NULL) 2696 return false; 2697 2698 while (an->tn_right != NULL) 2699 an = an->tn_right; 2700 return is_const_char_pointer(an->tn_left); 2701 } 2702 2703 static bool 2704 is_const_pointer(const tnode_t *tn) 2705 { 2706 const type_t *tp = before_conversion(tn)->tn_type; 2707 return tp->t_tspec == PTR && tp->t_subt->t_const; 2708 } 2709 2710 static bool 2711 is_second_arg_const_pointer(const tnode_t *tn) 2712 { 2713 const tnode_t *an = tn->tn_right; 2714 if (an == NULL || an->tn_right == NULL) 2715 return false; 2716 2717 while (an->tn_right->tn_right != NULL) 2718 an = an->tn_right; 2719 return is_const_pointer(an->tn_left); 2720 } 2721 2722 static void 2723 check_unconst_function(const type_t *lstp, const tnode_t *rn) 2724 { 2725 const char *function_name; 2726 2727 if (lstp->t_tspec == CHAR && !lstp->t_const && 2728 is_direct_function_call(rn, &function_name) && 2729 is_unconst_function(function_name) && 2730 is_first_arg_const_char_pointer(rn)) { 2731 /* call to '%s' effectively discards 'const' from argument */ 2732 warning(346, function_name); 2733 } 2734 2735 if (!lstp->t_const && 2736 is_direct_function_call(rn, &function_name) && 2737 strcmp(function_name, "bsearch") == 0 && 2738 is_second_arg_const_pointer(rn)) { 2739 /* call to '%s' effectively discards 'const' from argument */ 2740 warning(346, function_name); 2741 } 2742 } 2743 2744 static bool 2745 check_assign_void_pointer_compat(op_t op, int arg, 2746 const type_t *const ltp, tspec_t const lt, 2747 const type_t *const lstp, tspec_t const lst, 2748 const tnode_t *const rn, 2749 const type_t *const rtp, tspec_t const rt, 2750 const type_t *const rstp, tspec_t const rst) 2751 { 2752 if (!(lt == PTR && rt == PTR && (lst == VOID || rst == VOID || 2753 types_compatible(lstp, rstp, 2754 true, false, NULL)))) 2755 return false; 2756 2757 /* compatible pointer types (qualifiers ignored) */ 2758 if (allow_c90 && 2759 ((!lstp->t_const && rstp->t_const) || 2760 (!lstp->t_volatile && rstp->t_volatile))) { 2761 /* left side has not all qualifiers of right */ 2762 switch (op) { 2763 case INIT: 2764 case RETURN: 2765 /* incompatible pointer types to '%s' and '%s' */ 2766 warning(182, type_name(lstp), type_name(rstp)); 2767 break; 2768 case FARG: 2769 /* converting '%s' to incompatible '%s' ... */ 2770 warning(153, 2771 type_name(rtp), type_name(ltp), arg); 2772 break; 2773 default: 2774 /* operands of '%s' have incompatible pointer ... */ 2775 warning(128, op_name(op), 2776 type_name(lstp), type_name(rstp)); 2777 break; 2778 } 2779 } 2780 2781 if (allow_c90) 2782 check_unconst_function(lstp, rn); 2783 2784 return true; 2785 } 2786 2787 static bool 2788 check_assign_pointer_integer(op_t op, int arg, 2789 const type_t *const ltp, tspec_t const lt, 2790 const type_t *const rtp, tspec_t const rt) 2791 { 2792 2793 if (!((lt == PTR && is_integer(rt)) || (is_integer(lt) && rt == PTR))) 2794 return false; 2795 2796 const char *lx = lt == PTR ? "pointer" : "integer"; 2797 const char *rx = rt == PTR ? "pointer" : "integer"; 2798 2799 switch (op) { 2800 case INIT: 2801 case RETURN: 2802 /* illegal combination of %s '%s' and %s '%s' */ 2803 warning(183, lx, type_name(ltp), rx, type_name(rtp)); 2804 break; 2805 case FARG: 2806 /* illegal combination of %s '%s' and %s '%s', arg #%d */ 2807 warning(154, 2808 lx, type_name(ltp), rx, type_name(rtp), arg); 2809 break; 2810 default: 2811 /* illegal combination of %s '%s' and %s '%s', op '%s' */ 2812 warning(123, 2813 lx, type_name(ltp), rx, type_name(rtp), op_name(op)); 2814 break; 2815 } 2816 return true; 2817 } 2818 2819 static bool 2820 check_assign_pointer(op_t op, int arg, 2821 const type_t *ltp, tspec_t lt, 2822 const type_t *rtp, tspec_t rt) 2823 { 2824 if (!(lt == PTR && rt == PTR)) 2825 return false; 2826 2827 switch (op) { 2828 case RETURN: 2829 warn_incompatible_pointers(NULL, ltp, rtp); 2830 break; 2831 case FARG: 2832 /* converting '%s' to incompatible '%s' for ... */ 2833 warning(153, type_name(rtp), type_name(ltp), arg); 2834 break; 2835 default: 2836 warn_incompatible_pointers(&modtab[op], ltp, rtp); 2837 break; 2838 } 2839 return true; 2840 } 2841 2842 static void 2843 warn_assign(op_t op, int arg, 2844 const type_t *ltp, tspec_t lt, 2845 const type_t *rtp, tspec_t rt) 2846 { 2847 switch (op) { 2848 case INIT: 2849 /* cannot initialize '%s' from '%s' */ 2850 error(185, type_name(ltp), type_name(rtp)); 2851 break; 2852 case RETURN: 2853 /* function has return type '%s' but returns '%s' */ 2854 error(211, type_name(ltp), type_name(rtp)); 2855 break; 2856 case FARG: 2857 /* passing '%s' to incompatible '%s', arg #%d */ 2858 warning(155, type_name(rtp), type_name(ltp), arg); 2859 break; 2860 default: 2861 warn_incompatible_types(op, ltp, lt, rtp, rt); 2862 break; 2863 } 2864 } 2865 2866 /* 2867 * Checks type compatibility for ASSIGN, INIT, FARG and RETURN 2868 * and prints warnings/errors if necessary. 2869 * Returns whether the types are (almost) compatible. 2870 */ 2871 static bool 2872 check_assign_types_compatible(op_t op, int arg, 2873 const tnode_t *ln, const tnode_t *rn) 2874 { 2875 tspec_t lt, rt, lst = NO_TSPEC, rst = NO_TSPEC; 2876 type_t *ltp, *rtp, *lstp = NULL, *rstp = NULL; 2877 2878 if ((lt = (ltp = ln->tn_type)->t_tspec) == PTR) 2879 lst = (lstp = ltp->t_subt)->t_tspec; 2880 if ((rt = (rtp = rn->tn_type)->t_tspec) == PTR) 2881 rst = (rstp = rtp->t_subt)->t_tspec; 2882 2883 if (lt == BOOL && is_scalar(rt)) /* C99 6.3.1.2 */ 2884 return true; 2885 2886 if (is_arithmetic(lt) && (is_arithmetic(rt) || rt == BOOL)) 2887 return true; 2888 2889 if (is_struct_or_union(lt) && is_struct_or_union(rt)) 2890 /* both are struct or union */ 2891 return ltp->t_sou == rtp->t_sou; 2892 2893 /* a null pointer may be assigned to any pointer */ 2894 if (lt == PTR && is_null_pointer(rn)) { 2895 if (is_integer(rn->tn_type->t_tspec)) 2896 /* implicit conversion from integer 0 to pointer ... */ 2897 query_message(15, type_name(ltp)); 2898 return true; 2899 } 2900 2901 check_assign_void_pointer(op, arg, lt, lst, rt, rst); 2902 2903 if (check_assign_void_pointer_compat(op, arg, 2904 ltp, lt, lstp, lst, rn, rtp, rt, rstp, rst)) 2905 return true; 2906 2907 if (check_assign_pointer_integer(op, arg, ltp, lt, rtp, rt)) 2908 return true; 2909 2910 if (check_assign_pointer(op, arg, ltp, lt, rtp, rt)) 2911 return true; 2912 2913 warn_assign(op, arg, ltp, lt, rtp, rt); 2914 return false; 2915 } 2916 2917 static bool 2918 has_side_effect(const tnode_t *tn) /* NOLINT(misc-no-recursion) */ 2919 { 2920 op_t op = tn->tn_op; 2921 2922 if (modtab[op].m_has_side_effect) 2923 return true; 2924 2925 if (op == CVT && tn->tn_type->t_tspec == VOID) 2926 return has_side_effect(tn->tn_left); 2927 2928 /* XXX: Why not has_side_effect(tn->tn_left) as well? */ 2929 if (op == LOGAND || op == LOGOR) 2930 return has_side_effect(tn->tn_right); 2931 2932 /* XXX: Why not has_side_effect(tn->tn_left) as well? */ 2933 if (op == QUEST) 2934 return has_side_effect(tn->tn_right); 2935 2936 if (op == COLON || op == COMMA) { 2937 return has_side_effect(tn->tn_left) || 2938 has_side_effect(tn->tn_right); 2939 } 2940 2941 return false; 2942 } 2943 2944 static bool 2945 is_void_cast(const tnode_t *tn) 2946 { 2947 2948 return tn->tn_op == CVT && tn->tn_cast && 2949 tn->tn_type->t_tspec == VOID; 2950 } 2951 2952 static bool 2953 is_local_symbol(const tnode_t *tn) 2954 { 2955 2956 return tn->tn_op == LOAD && 2957 tn->tn_left->tn_op == NAME && 2958 tn->tn_left->tn_sym->s_scl == AUTO; 2959 } 2960 2961 static bool 2962 is_int_constant_zero(const tnode_t *tn) 2963 { 2964 2965 return tn->tn_op == CON && 2966 tn->tn_type->t_tspec == INT && 2967 tn->tn_val.u.integer == 0; 2968 } 2969 2970 static void 2971 check_null_effect(const tnode_t *tn) 2972 { 2973 2974 if (hflag && 2975 !has_side_effect(tn) && 2976 !(is_void_cast(tn) && is_local_symbol(tn->tn_left)) && 2977 !(is_void_cast(tn) && is_int_constant_zero(tn->tn_left))) { 2978 /* expression has null effect */ 2979 warning(129); 2980 } 2981 } 2982 2983 /* 2984 * Check the types for specific operators and type combinations. 2985 * 2986 * At this point, the operands already conform to the type requirements of 2987 * the operator, such as being integer, floating or scalar. 2988 */ 2989 static bool 2990 typeok_op(op_t op, const mod_t *mp, int arg, 2991 const tnode_t *ln, const type_t *ltp, tspec_t lt, 2992 const tnode_t *rn, const type_t *rtp, tspec_t rt) 2993 { 2994 switch (op) { 2995 case ARROW: 2996 return typeok_arrow(lt); 2997 case POINT: 2998 return typeok_point(ln, ltp, lt); 2999 case INCBEF: 3000 case DECBEF: 3001 case INCAFT: 3002 case DECAFT: 3003 return typeok_incdec(op, ln, ltp); 3004 case INDIR: 3005 return typeok_indir(ltp, lt); 3006 case ADDR: 3007 return typeok_address(mp, ln, ltp, lt); 3008 case PLUS: 3009 return typeok_plus(op, ltp, lt, rtp, rt); 3010 case MINUS: 3011 return typeok_minus(op, ltp, lt, rtp, rt); 3012 case SHL: 3013 typeok_shl(mp, lt, rt); 3014 goto shift; 3015 case SHR: 3016 typeok_shr(mp, ln, lt, rn, rt); 3017 shift: 3018 typeok_shift(ltp, lt, rn, rt); 3019 break; 3020 case LT: 3021 case LE: 3022 case GT: 3023 case GE: 3024 compare: 3025 return typeok_compare(op, ln, ltp, lt, rn, rtp, rt); 3026 case EQ: 3027 case NE: 3028 if (is_typeok_eq(ln, lt, rn, rt)) 3029 break; 3030 goto compare; 3031 case QUEST: 3032 return typeok_quest(lt, rn); 3033 case COLON: 3034 return typeok_colon(mp, ln, ltp, lt, rn, rtp, rt); 3035 case ASSIGN: 3036 case INIT: 3037 case FARG: 3038 case RETURN: 3039 if (!check_assign_types_compatible(op, arg, ln, rn)) 3040 return false; 3041 goto assign; 3042 case MULASS: 3043 case DIVASS: 3044 case MODASS: 3045 goto assign; 3046 case ADDASS: 3047 case SUBASS: 3048 if ((lt == PTR && !is_integer(rt)) || rt == PTR) { 3049 warn_incompatible_types(op, ltp, lt, rtp, rt); 3050 return false; 3051 } 3052 goto assign; 3053 case SHLASS: 3054 goto assign; 3055 case SHRASS: 3056 if (pflag && !is_uinteger(lt) && 3057 !(!allow_c90 && is_uinteger(rt))) { 3058 /* bitwise '%s' on signed value possibly nonportable */ 3059 warning(117, mp->m_name); 3060 } 3061 goto assign; 3062 case ANDASS: 3063 case XORASS: 3064 case ORASS: 3065 assign: 3066 return typeok_assign(op, ln, ltp, lt); 3067 case COMMA: 3068 if (!modtab[ln->tn_op].m_has_side_effect) 3069 check_null_effect(ln); 3070 break; 3071 default: 3072 break; 3073 } 3074 return true; 3075 } 3076 3077 /* Prints a warning if a strange operator is used on an enum type. */ 3078 static void 3079 check_bad_enum_operation(op_t op, const tnode_t *ln, const tnode_t *rn) 3080 { 3081 3082 if (!eflag) 3083 return; 3084 3085 /* Allow enum in array indices. */ 3086 if (op == PLUS && 3087 ((ln->tn_type->t_is_enum && rn->tn_type->t_tspec == PTR) || 3088 (rn->tn_type->t_is_enum && ln->tn_type->t_tspec == PTR))) { 3089 return; 3090 } 3091 3092 /* dubious operation on enum, op '%s' */ 3093 warning(241, op_name(op)); 3094 } 3095 3096 /* Prints a warning if an operator is applied to two different enum types. */ 3097 static void 3098 check_enum_type_mismatch(op_t op, int arg, const tnode_t *ln, const tnode_t *rn) 3099 { 3100 const mod_t *mp = &modtab[op]; 3101 3102 if (ln->tn_type->t_enum != rn->tn_type->t_enum) { 3103 switch (op) { 3104 case INIT: 3105 /* enum type mismatch between '%s' and '%s' in ... */ 3106 warning(210, 3107 type_name(ln->tn_type), type_name(rn->tn_type)); 3108 break; 3109 case FARG: 3110 /* function expects '%s', passing '%s' for arg #%d */ 3111 warning(156, 3112 type_name(ln->tn_type), type_name(rn->tn_type), 3113 arg); 3114 break; 3115 case RETURN: 3116 /* function has return type '%s' but returns '%s' */ 3117 warning(211, 3118 type_name(ln->tn_type), type_name(rn->tn_type)); 3119 break; 3120 default: 3121 /* enum type mismatch: '%s' '%s' '%s' */ 3122 warning(130, type_name(ln->tn_type), mp->m_name, 3123 type_name(rn->tn_type)); 3124 break; 3125 } 3126 } else if (Pflag && mp->m_comparison && op != EQ && op != NE) { 3127 if (eflag) 3128 /* dubious comparison of enums, op '%s' */ 3129 warning(243, mp->m_name); 3130 } 3131 } 3132 3133 /* Prints a warning if the operands mix between enum and integer. */ 3134 static void 3135 check_enum_int_mismatch(op_t op, int arg, const tnode_t *ln, const tnode_t *rn) 3136 { 3137 3138 if (!eflag) 3139 return; 3140 3141 switch (op) { 3142 case INIT: 3143 /* 3144 * Initialization with 0 is allowed. Otherwise, all implicit 3145 * initializations would need to be warned upon as well. 3146 */ 3147 if (!rn->tn_type->t_is_enum && rn->tn_op == CON && 3148 is_integer(rn->tn_type->t_tspec) && 3149 rn->tn_val.u.integer == 0) { 3150 return; 3151 } 3152 /* initialization of '%s' with '%s' */ 3153 warning(277, type_name(ln->tn_type), type_name(rn->tn_type)); 3154 break; 3155 case FARG: 3156 /* combination of '%s' and '%s', arg #%d */ 3157 warning(278, 3158 type_name(ln->tn_type), type_name(rn->tn_type), arg); 3159 break; 3160 case RETURN: 3161 /* combination of '%s' and '%s' in return */ 3162 warning(279, type_name(ln->tn_type), type_name(rn->tn_type)); 3163 break; 3164 default: 3165 /* combination of '%s' and '%s', op '%s' */ 3166 warning(242, type_name(ln->tn_type), type_name(rn->tn_type), 3167 op_name(op)); 3168 break; 3169 } 3170 } 3171 3172 static void 3173 typeok_enum(op_t op, const mod_t *mp, int arg, 3174 const tnode_t *ln, const type_t *ltp, 3175 const tnode_t *rn, const type_t *rtp) 3176 { 3177 if (mp->m_bad_on_enum && 3178 (ltp->t_is_enum || (mp->m_binary && rtp->t_is_enum))) { 3179 check_bad_enum_operation(op, ln, rn); 3180 } else if (mp->m_valid_on_enum && 3181 (ltp->t_is_enum && rtp != NULL && rtp->t_is_enum)) { 3182 check_enum_type_mismatch(op, arg, ln, rn); 3183 } else if (mp->m_valid_on_enum && 3184 (ltp->t_is_enum || (rtp != NULL && rtp->t_is_enum))) { 3185 check_enum_int_mismatch(op, arg, ln, rn); 3186 } 3187 } 3188 3189 /* Perform most type checks. Return whether the types are ok. */ 3190 bool 3191 typeok(op_t op, int arg, const tnode_t *ln, const tnode_t *rn) 3192 { 3193 3194 const mod_t *mp = &modtab[op]; 3195 3196 type_t *ltp = ln->tn_type; 3197 tspec_t lt = ltp->t_tspec; 3198 3199 type_t *rtp = mp->m_binary ? rn->tn_type : NULL; 3200 tspec_t rt = mp->m_binary ? rtp->t_tspec : NO_TSPEC; 3201 3202 if (Tflag && !typeok_scalar_strict_bool(op, mp, arg, ln, rn)) 3203 return false; 3204 if (!typeok_scalar(op, mp, ltp, lt, rtp, rt)) 3205 return false; 3206 3207 if (!typeok_op(op, mp, arg, ln, ltp, lt, rn, rtp, rt)) 3208 return false; 3209 3210 typeok_enum(op, mp, arg, ln, ltp, rn, rtp); 3211 return true; 3212 } 3213 3214 /* In traditional C, keep unsigned and promote FLOAT to DOUBLE. */ 3215 static tspec_t 3216 promote_trad(tspec_t t) 3217 { 3218 3219 if (t == UCHAR || t == USHORT) 3220 return UINT; 3221 if (t == CHAR || t == SCHAR || t == SHORT) 3222 return INT; 3223 if (t == FLOAT) 3224 return DOUBLE; 3225 if (t == ENUM) 3226 return INT; 3227 return t; 3228 } 3229 3230 /* 3231 * C99 6.3.1.1p2 requires for types with lower rank than int that "If an int 3232 * can represent all the values of the original type, the value is converted 3233 * to an int; otherwise it is converted to an unsigned int", and that "All 3234 * other types are unchanged by the integer promotions". 3235 */ 3236 static tspec_t 3237 promote_c90(const tnode_t *tn, tspec_t t, bool farg) 3238 { 3239 if (tn->tn_type->t_bitfield) { 3240 unsigned int width = tn->tn_type->t_bit_field_width; 3241 unsigned int int_width = size_in_bits(INT); 3242 // XXX: What about _Bool bit-fields, since C99? 3243 if (width < int_width) 3244 return INT; 3245 if (width == int_width) 3246 return is_uinteger(t) ? UINT : INT; 3247 return t; 3248 } 3249 3250 if (t == CHAR || t == SCHAR) 3251 return INT; 3252 if (t == UCHAR) 3253 return size_in_bits(CHAR) < size_in_bits(INT) ? INT : UINT; 3254 if (t == SHORT) 3255 return INT; 3256 if (t == USHORT) 3257 return size_in_bits(SHORT) < size_in_bits(INT) ? INT : UINT; 3258 if (t == ENUM) 3259 return INT; 3260 if (farg && t == FLOAT) 3261 return DOUBLE; 3262 return t; 3263 } 3264 3265 /* 3266 * Performs the "integer promotions" (C99 6.3.1.1p2), which convert small 3267 * integer types to either int or unsigned int. 3268 * 3269 * If allow_c90 is unset or the operand is a function argument with no type 3270 * information (no prototype or variable # of args), converts float to double. 3271 */ 3272 tnode_t * 3273 promote(op_t op, bool farg, tnode_t *tn) 3274 { 3275 3276 tspec_t ot = tn->tn_type->t_tspec; 3277 if (!is_arithmetic(ot)) 3278 return tn; 3279 3280 tspec_t nt = allow_c90 ? promote_c90(tn, ot, farg) : promote_trad(ot); 3281 if (nt == ot) 3282 return tn; 3283 3284 type_t *ntp = expr_dup_type(tn->tn_type); 3285 ntp->t_tspec = nt; 3286 /* 3287 * Keep t_is_enum even though t_tspec gets converted from 3288 * ENUM to INT, so we are later able to check compatibility 3289 * of enum types. 3290 */ 3291 return convert(op, 0, ntp, tn); 3292 } 3293 3294 static void 3295 convert_integer_from_floating(op_t op, const type_t *tp, const tnode_t *tn) 3296 { 3297 3298 if (op == CVT) 3299 /* cast from floating point '%s' to integer '%s' */ 3300 query_message(2, type_name(tn->tn_type), type_name(tp)); 3301 else 3302 /* implicit conversion from floating point '%s' to ... */ 3303 query_message(1, type_name(tn->tn_type), type_name(tp)); 3304 } 3305 3306 static bool 3307 should_warn_about_prototype_conversion(tspec_t nt, 3308 tspec_t ot, const tnode_t *ptn) 3309 { 3310 3311 if (nt == ot) 3312 return false; 3313 3314 if (nt == ENUM && ot == INT) 3315 return false; 3316 3317 if (is_floating(nt) != is_floating(ot) || 3318 portable_size_in_bits(nt) != portable_size_in_bits(ot)) { 3319 /* representation and/or width change */ 3320 if (!is_integer(ot)) 3321 return true; 3322 /* 3323 * XXX: Investigate whether this rule makes sense; see 3324 * tests/usr.bin/xlint/lint1/platform_long.c. 3325 */ 3326 return portable_size_in_bits(ot) > portable_size_in_bits(INT); 3327 } 3328 3329 if (!hflag) 3330 return false; 3331 3332 /* 3333 * If the types differ only in sign and the argument has the same 3334 * representation in both types, print no warning. 3335 */ 3336 if (ptn->tn_op == CON && is_integer(nt) && 3337 signed_type(nt) == signed_type(ot) && 3338 !msb(ptn->tn_val.u.integer, ot)) 3339 return false; 3340 3341 return true; 3342 } 3343 3344 /* 3345 * Warn if a prototype causes a type conversion that is different from what 3346 * would happen to the same argument in the absence of a prototype. This 3347 * check is intended for code that needs to stay compatible with pre-C90 C. 3348 * 3349 * Errors/warnings about illegal type combinations are already printed 3350 * in check_assign_types_compatible(). 3351 */ 3352 static void 3353 check_prototype_conversion(int arg, tspec_t nt, tspec_t ot, type_t *tp, 3354 tnode_t *tn) 3355 { 3356 3357 if (!is_arithmetic(nt) || !is_arithmetic(ot)) 3358 return; 3359 3360 /* 3361 * If the type of the formal parameter is char/short, a warning 3362 * would be useless, because functions declared the old style 3363 * can't expect char/short arguments. 3364 */ 3365 if (nt == CHAR || nt == SCHAR || nt == UCHAR || 3366 nt == SHORT || nt == USHORT) 3367 return; 3368 3369 /* apply the default promotion */ 3370 tnode_t *ptn = promote(NOOP, true, tn); 3371 ot = ptn->tn_type->t_tspec; 3372 3373 if (should_warn_about_prototype_conversion(nt, ot, ptn)) { 3374 /* argument #%d is converted from '%s' to '%s' ... */ 3375 warning(259, arg, type_name(tn->tn_type), type_name(tp)); 3376 } 3377 } 3378 3379 /* 3380 * When converting a large integer type to a small integer type, in some 3381 * cases the value of the actual expression is further restricted than the 3382 * type bounds, such as in (expr & 0xFF) or (expr % 100) or (expr >> 24). 3383 */ 3384 static bool 3385 can_represent(const type_t *tp, const tnode_t *tn) 3386 { 3387 3388 debug_step("%s: type '%s'", __func__, type_name(tp)); 3389 debug_node(tn); 3390 3391 uint64_t nmask = value_bits(width_in_bits(tp)); 3392 if (!is_uinteger(tp->t_tspec)) 3393 nmask >>= 1; 3394 3395 integer_constraints c = ic_expr(tn); 3396 if ((~c.bclr & ~nmask) == 0) 3397 return true; 3398 3399 integer_constraints tpc = ic_any(tp); 3400 if (is_uinteger(tp->t_tspec) 3401 ? tpc.umin <= c.umin && tpc.umax >= c.umax 3402 : tpc.smin <= c.smin && tpc.smax >= c.smax) 3403 return true; 3404 3405 return false; 3406 } 3407 3408 static void 3409 convert_integer_from_integer(op_t op, int arg, tspec_t nt, tspec_t ot, 3410 type_t *tp, tnode_t *tn) 3411 { 3412 3413 if (tn->tn_op == CON) 3414 return; 3415 3416 if (op == CVT) 3417 return; 3418 3419 if (Pflag && pflag && aflag > 0 && 3420 portable_size_in_bits(nt) > portable_size_in_bits(ot) && 3421 is_uinteger(nt) != is_uinteger(ot)) { 3422 if (op == FARG) { 3423 /* conversion to '%s' may sign-extend ... */ 3424 warning(297, type_name(tp), arg); 3425 } else { 3426 /* conversion to '%s' may sign-extend ... */ 3427 warning(131, type_name(tp)); 3428 } 3429 } 3430 3431 if (Pflag && portable_size_in_bits(nt) > portable_size_in_bits(ot) && 3432 (tn->tn_op == PLUS || tn->tn_op == MINUS || tn->tn_op == MULT || 3433 tn->tn_op == SHL)) { 3434 /* suggest cast from '%s' to '%s' on op '%s' to ... */ 3435 warning(324, type_name(gettyp(ot)), type_name(tp), 3436 op_name(tn->tn_op)); 3437 } 3438 3439 if (aflag > 0 && 3440 portable_size_in_bits(nt) < portable_size_in_bits(ot) && 3441 (ot == LONG || ot == ULONG || ot == LLONG || ot == ULLONG || 3442 aflag > 1) && 3443 !can_represent(tp, tn)) { 3444 if (op == FARG) { 3445 /* conversion from '%s' to '%s' may lose ... */ 3446 warning(298, 3447 type_name(tn->tn_type), type_name(tp), arg); 3448 } else { 3449 /* conversion from '%s' to '%s' may lose accuracy */ 3450 warning(132, 3451 type_name(tn->tn_type), type_name(tp)); 3452 } 3453 } 3454 3455 if (is_uinteger(nt) != is_uinteger(ot)) 3456 /* implicit conversion changes sign from '%s' to '%s' */ 3457 query_message(3, type_name(tn->tn_type), type_name(tp)); 3458 } 3459 3460 static void 3461 convert_integer_from_pointer(op_t op, tspec_t nt, type_t *tp, tnode_t *tn) 3462 { 3463 3464 if (tn->tn_op == CON) 3465 return; 3466 if (op != CVT) 3467 return; /* We already got an error. */ 3468 if (portable_size_in_bits(nt) >= portable_size_in_bits(PTR)) 3469 return; 3470 3471 if (pflag && size_in_bits(nt) >= size_in_bits(PTR)) { 3472 /* conversion of pointer to '%s' may lose bits */ 3473 warning(134, type_name(tp)); 3474 } else { 3475 /* conversion of pointer to '%s' loses bits */ 3476 warning(133, type_name(tp)); 3477 } 3478 } 3479 3480 static bool 3481 struct_starts_with(const type_t *struct_tp, const type_t *member_tp) 3482 { 3483 3484 return struct_tp->t_sou->sou_first_member != NULL && 3485 types_compatible(struct_tp->t_sou->sou_first_member->s_type, 3486 member_tp, true, false, NULL); 3487 } 3488 3489 static bool 3490 is_byte_array(const type_t *tp) 3491 { 3492 3493 return tp->t_tspec == ARRAY && 3494 (tp->t_subt->t_tspec == CHAR || tp->t_subt->t_tspec == UCHAR); 3495 } 3496 3497 static bool 3498 union_contains(const type_t *utp, const type_t *mtp) 3499 { 3500 for (const sym_t *mem = utp->t_sou->sou_first_member; 3501 mem != NULL; mem = mem->s_next) { 3502 if (types_compatible(mem->s_type, mtp, true, false, NULL)) 3503 return true; 3504 } 3505 return false; 3506 } 3507 3508 static bool 3509 should_warn_about_pointer_cast(const type_t *nstp, tspec_t nst, 3510 const type_t *ostp, tspec_t ost) 3511 { 3512 3513 while (nst == ARRAY) 3514 nstp = nstp->t_subt, nst = nstp->t_tspec; 3515 while (ost == ARRAY) 3516 ostp = ostp->t_subt, ost = ostp->t_tspec; 3517 3518 if (nst == STRUCT && ost == STRUCT && 3519 (struct_starts_with(nstp, ostp) || 3520 struct_starts_with(ostp, nstp))) 3521 return false; 3522 3523 if (is_incomplete(nstp) || is_incomplete(ostp)) 3524 return false; 3525 3526 if (nst == CHAR || nst == UCHAR) 3527 return false; /* for the sake of traditional C code */ 3528 if (ost == CHAR || ost == UCHAR) 3529 return false; /* for the sake of traditional C code */ 3530 3531 /* Allow cast between pointers to sockaddr variants. */ 3532 if (nst == STRUCT && ost == STRUCT) { 3533 debug_type(nstp); 3534 debug_type(ostp); 3535 const sym_t *nmem = nstp->t_sou->sou_first_member; 3536 const sym_t *omem = ostp->t_sou->sou_first_member; 3537 while (nmem != NULL && omem != NULL && 3538 types_compatible(nmem->s_type, omem->s_type, 3539 true, false, NULL)) 3540 nmem = nmem->s_next, omem = omem->s_next; 3541 if (nmem != NULL && is_byte_array(nmem->s_type)) 3542 return false; 3543 if (omem != NULL && is_byte_array(omem->s_type)) 3544 return false; 3545 if (nmem == NULL && omem == NULL) 3546 return false; 3547 } 3548 3549 if (nst == UNION || ost == UNION) { 3550 const type_t *union_tp = nst == UNION ? nstp : ostp; 3551 const type_t *other_tp = nst == UNION ? ostp : nstp; 3552 if (union_contains(union_tp, other_tp)) 3553 return false; 3554 } 3555 3556 if (is_struct_or_union(nst) && nstp->t_sou != ostp->t_sou) 3557 return true; 3558 3559 return portable_size_in_bits(nst) != portable_size_in_bits(ost); 3560 } 3561 3562 static void 3563 convert_pointer_from_pointer(type_t *ntp, tnode_t *tn) 3564 { 3565 const type_t *nstp = ntp->t_subt; 3566 const type_t *otp = tn->tn_type; 3567 const type_t *ostp = otp->t_subt; 3568 tspec_t nst = nstp->t_tspec; 3569 tspec_t ost = ostp->t_tspec; 3570 3571 if (nst == VOID || ost == VOID) { 3572 /* TODO: C99 behaves like C90 here. */ 3573 if ((!allow_trad && !allow_c99) && (nst == FUNC || ost == FUNC)) { 3574 const char *nts, *ots; 3575 /* null pointers are already handled in convert() */ 3576 *(nst == FUNC ? &nts : &ots) = "function pointer"; 3577 *(nst == VOID ? &nts : &ots) = "'void *'"; 3578 /* ANSI C forbids conversion of %s to %s */ 3579 warning(303, ots, nts); 3580 } 3581 return; 3582 } 3583 if (nst == FUNC && ost == FUNC) 3584 return; 3585 if (nst == FUNC || ost == FUNC) { 3586 /* converting '%s' to '%s' is questionable */ 3587 warning(229, type_name(otp), type_name(ntp)); 3588 return; 3589 } 3590 3591 if (hflag && alignment_in_bits(nstp) > alignment_in_bits(ostp) && 3592 ost != CHAR && ost != UCHAR && 3593 !is_incomplete(ostp) && 3594 !(nst == UNION && union_contains(nstp, ostp))) { 3595 /* converting '%s' to '%s' increases alignment ... */ 3596 warning(135, type_name(otp), type_name(ntp), 3597 alignment_in_bits(ostp) / CHAR_SIZE, 3598 alignment_in_bits(nstp) / CHAR_SIZE); 3599 } 3600 3601 if (cflag && should_warn_about_pointer_cast(nstp, nst, ostp, ost)) { 3602 /* pointer cast from '%s' to '%s' may be troublesome */ 3603 warning(247, type_name(otp), type_name(ntp)); 3604 } 3605 } 3606 3607 /* 3608 * Insert a conversion operator, which converts the type of the node 3609 * to another given type. 3610 * 3611 * Possible values for 'op': 3612 * CVT a cast-expression 3613 * binary integer promotion for one of the operands, or a usual 3614 * arithmetic conversion 3615 * binary plain or compound assignments to bit-fields 3616 * FARG 'arg' is the number of the argument (used for warnings) 3617 * NOOP several other implicit conversions 3618 * ... 3619 */ 3620 tnode_t * 3621 convert(op_t op, int arg, type_t *tp, tnode_t *tn) 3622 { 3623 tspec_t nt = tp->t_tspec; 3624 tspec_t ot = tn->tn_type->t_tspec; 3625 3626 if (allow_trad && allow_c90 && op == FARG) 3627 check_prototype_conversion(arg, nt, ot, tp, tn); 3628 3629 if (nt == BOOL) { 3630 /* No further checks. */ 3631 3632 } else if (is_integer(nt)) { 3633 if (ot == BOOL) { 3634 /* No further checks. */ 3635 } else if (is_integer(ot)) 3636 convert_integer_from_integer(op, arg, nt, ot, tp, tn); 3637 else if (is_floating(ot)) 3638 convert_integer_from_floating(op, tp, tn); 3639 else if (ot == PTR) 3640 convert_integer_from_pointer(op, nt, tp, tn); 3641 3642 } else if (is_floating(nt)) { 3643 /* No further checks. */ 3644 3645 } else if (nt == PTR) { 3646 if (is_null_pointer(tn)) { 3647 /* a null pointer may be assigned to any pointer. */ 3648 } else if (ot == PTR && op == CVT) 3649 convert_pointer_from_pointer(tp, tn); 3650 } 3651 3652 tnode_t *ntn = expr_alloc_tnode(); 3653 ntn->tn_op = CVT; 3654 ntn->tn_type = tp; 3655 ntn->tn_cast = op == CVT; 3656 ntn->tn_sys |= tn->tn_sys; 3657 ntn->tn_right = NULL; 3658 if (tn->tn_op != CON || nt == VOID) { 3659 ntn->tn_left = tn; 3660 } else { 3661 ntn->tn_op = CON; 3662 convert_constant(op, arg, ntn->tn_type, &ntn->tn_val, 3663 &tn->tn_val); 3664 } 3665 3666 return ntn; 3667 } 3668 3669 static void 3670 convert_constant_floating(op_t op, int arg, tspec_t ot, const type_t *tp, 3671 tspec_t nt, val_t *v, val_t *nv) 3672 { 3673 long double max = 0.0, min = 0.0; 3674 3675 switch (nt) { 3676 case CHAR: 3677 max = TARG_CHAR_MAX; min = TARG_CHAR_MIN; break; 3678 case UCHAR: 3679 max = TARG_UCHAR_MAX; min = 0; break; 3680 case SCHAR: 3681 max = TARG_SCHAR_MAX; min = TARG_SCHAR_MIN; break; 3682 case SHORT: 3683 max = TARG_SHRT_MAX; min = TARG_SHRT_MIN; break; 3684 case USHORT: 3685 max = TARG_USHRT_MAX; min = 0; break; 3686 case ENUM: 3687 case INT: 3688 max = TARG_INT_MAX; min = TARG_INT_MIN; break; 3689 case UINT: 3690 max = TARG_UINT_MAX; min = 0; break; 3691 case LONG: 3692 max = TARG_LONG_MAX; min = TARG_LONG_MIN; break; 3693 case ULONG: 3694 max = TARG_ULONG_MAX; min = 0; break; 3695 case LLONG: 3696 max = LLONG_MAX; min = LLONG_MIN; break; 3697 case ULLONG: 3698 max = ULLONG_MAX; min = 0; break; 3699 case FLOAT: 3700 case FCOMPLEX: 3701 max = FLT_MAX; min = -FLT_MAX; break; 3702 case DOUBLE: 3703 case DCOMPLEX: 3704 max = DBL_MAX; min = -DBL_MAX; break; 3705 case PTR: 3706 /* Already got an error because of float --> ptr */ 3707 case LDOUBLE: 3708 case LCOMPLEX: 3709 /* LINTED 248 */ 3710 max = LDBL_MAX; min = -max; break; 3711 default: 3712 lint_assert(/*CONSTCOND*/false); 3713 } 3714 if (v->u.floating > max || v->u.floating < min) { 3715 lint_assert(nt != LDOUBLE); 3716 if (op == FARG) { 3717 /* conversion of '%s' to '%s' is out of range, ... */ 3718 warning(295, 3719 type_name(gettyp(ot)), type_name(tp), arg); 3720 } else { 3721 /* conversion of '%s' to '%s' is out of range */ 3722 warning(119, type_name(gettyp(ot)), type_name(tp)); 3723 } 3724 v->u.floating = v->u.floating > 0 ? max : min; 3725 } 3726 3727 if (nt == FLOAT || nt == FCOMPLEX) 3728 nv->u.floating = (float)v->u.floating; 3729 else if (nt == DOUBLE || nt == DCOMPLEX) 3730 nv->u.floating = (double)v->u.floating; 3731 else if (nt == LDOUBLE || nt == LCOMPLEX) 3732 nv->u.floating = v->u.floating; 3733 else 3734 nv->u.integer = (int64_t)v->u.floating; 3735 } 3736 3737 static bool 3738 convert_constant_to_floating(tspec_t nt, val_t *nv, 3739 tspec_t ot, const val_t *v) 3740 { 3741 if (nt == FLOAT) { 3742 nv->u.floating = (ot == PTR || is_uinteger(ot)) ? 3743 (float)(uint64_t)v->u.integer : (float)v->u.integer; 3744 } else if (nt == DOUBLE) { 3745 nv->u.floating = (ot == PTR || is_uinteger(ot)) ? 3746 (double)(uint64_t)v->u.integer : (double)v->u.integer; 3747 } else if (nt == LDOUBLE) { 3748 nv->u.floating = (ot == PTR || is_uinteger(ot)) 3749 ? (long double)(uint64_t)v->u.integer 3750 : (long double)v->u.integer; 3751 } else 3752 return false; 3753 return true; 3754 } 3755 3756 /* 3757 * Print a warning if bits which were set are lost due to the conversion. 3758 * This can happen with operator ORASS only. 3759 */ 3760 static void 3761 convert_constant_check_range_bitor(size_t nsz, size_t osz, const val_t *v, 3762 uint64_t xmask, op_t op) 3763 { 3764 if (nsz < osz && (v->u.integer & xmask) != 0) { 3765 /* constant truncated by conversion, op '%s' */ 3766 warning(306, op_name(op)); 3767 } 3768 } 3769 3770 /* 3771 * Print a warning if additional bits are not all 1 3772 * and the most significant bit of the old value is 1, 3773 * or if at least one (but not all) removed bit was 0. 3774 */ 3775 static void 3776 convert_constant_check_range_bitand(size_t nsz, size_t osz, 3777 uint64_t xmask, const val_t *nv, 3778 tspec_t ot, const val_t *v, 3779 const type_t *tp, op_t op) 3780 { 3781 if (nsz > osz && 3782 (nv->u.integer & bit((unsigned int)(osz - 1))) != 0 && 3783 (nv->u.integer & xmask) != xmask) { 3784 /* extra bits set to 0 in conversion of '%s' to '%s', ... */ 3785 warning(309, type_name(gettyp(ot)), 3786 type_name(tp), op_name(op)); 3787 } else if (nsz < osz && 3788 (v->u.integer & xmask) != xmask && 3789 (v->u.integer & xmask) != 0) { 3790 /* constant truncated by conversion, op '%s' */ 3791 warning(306, op_name(op)); 3792 } 3793 } 3794 3795 static void 3796 convert_constant_check_range_signed(op_t op, int arg) 3797 { 3798 if (op == ASSIGN) { 3799 /* assignment of negative constant to unsigned type */ 3800 warning(164); 3801 } else if (op == INIT) { 3802 /* initialization of unsigned with negative constant */ 3803 warning(221); 3804 } else if (op == FARG) { 3805 /* conversion of negative constant to unsigned type, ... */ 3806 warning(296, arg); 3807 } else if (modtab[op].m_comparison) { 3808 /* handled by check_integer_comparison() */ 3809 } else { 3810 /* conversion of negative constant to unsigned type */ 3811 warning(222); 3812 } 3813 } 3814 3815 /* 3816 * Loss of significant bit(s). All truncated bits of unsigned types or all 3817 * truncated bits plus the msb of the target for signed types are considered 3818 * to be significant bits. Loss of significant bits means that at least one 3819 * of the bits was set in an unsigned type or that at least one but not all 3820 * of the bits was set in a signed type. Loss of significant bits means that 3821 * it is not possible, also not with necessary casts, to convert back to the 3822 * original type. An example for a necessary cast is: 3823 * char c; int i; c = 128; 3824 * i = c; ** yields -128 ** 3825 * i = (unsigned char)c; ** yields 128 ** 3826 */ 3827 static void 3828 warn_constant_check_range_truncated(op_t op, int arg, const type_t *tp, 3829 tspec_t ot) 3830 { 3831 if (op == ASSIGN && tp->t_bitfield) 3832 /* precision lost in bit-field assignment */ 3833 warning(166); 3834 else if (op == ASSIGN) 3835 /* constant truncated by assignment */ 3836 warning(165); 3837 else if (op == INIT && tp->t_bitfield) 3838 /* bit-field initializer does not fit */ 3839 warning(180); 3840 else if (op == INIT) 3841 /* initializer does not fit */ 3842 warning(178); 3843 else if (op == CASE) 3844 /* case label affected by conversion */ 3845 warning(196); 3846 else if (op == FARG) 3847 /* conversion of '%s' to '%s' is out of range, arg #%d */ 3848 warning(295, type_name(gettyp(ot)), type_name(tp), arg); 3849 else 3850 /* conversion of '%s' to '%s' is out of range */ 3851 warning(119, type_name(gettyp(ot)), type_name(tp)); 3852 } 3853 3854 static void 3855 warn_constant_check_range_loss(op_t op, int arg, const type_t *tp, 3856 tspec_t ot) 3857 { 3858 if (op == ASSIGN && tp->t_bitfield) 3859 /* precision lost in bit-field assignment */ 3860 warning(166); 3861 else if (op == INIT && tp->t_bitfield) 3862 /* bit-field initializer out of range */ 3863 warning(11); 3864 else if (op == CASE) 3865 /* case label affected by conversion */ 3866 warning(196); 3867 else if (op == FARG) 3868 /* conversion of '%s' to '%s' is out of range, arg #%d */ 3869 warning(295, type_name(gettyp(ot)), type_name(tp), arg); 3870 else 3871 /* conversion of '%s' to '%s' is out of range */ 3872 warning(119, type_name(gettyp(ot)), type_name(tp)); 3873 } 3874 3875 static void 3876 convert_constant_check_range(tspec_t ot, const type_t *tp, tspec_t nt, 3877 op_t op, int arg, const val_t *v, val_t *nv) 3878 { 3879 unsigned int obitsz, nbitsz; 3880 uint64_t xmask, xmsk1; 3881 3882 obitsz = size_in_bits(ot); 3883 nbitsz = tp->t_bitfield ? tp->t_bit_field_width : size_in_bits(nt); 3884 xmask = value_bits(nbitsz) ^ value_bits(obitsz); 3885 xmsk1 = value_bits(nbitsz) ^ value_bits(obitsz - 1); 3886 /* 3887 * For bitwise operations we are not interested in the arithmetic 3888 * value, but in the bits itself. 3889 */ 3890 if (op == ORASS || op == BITOR || op == BITXOR) { 3891 convert_constant_check_range_bitor( 3892 nbitsz, obitsz, v, xmask, op); 3893 } else if (op == ANDASS || op == BITAND) { 3894 convert_constant_check_range_bitand( 3895 nbitsz, obitsz, xmask, nv, ot, v, tp, op); 3896 } else if ((nt != PTR && is_uinteger(nt)) && 3897 (ot != PTR && !is_uinteger(ot)) && 3898 v->u.integer < 0) 3899 convert_constant_check_range_signed(op, arg); 3900 else if (nv->u.integer != v->u.integer && nbitsz <= obitsz && 3901 (v->u.integer & xmask) != 0 && 3902 (is_uinteger(ot) || (v->u.integer & xmsk1) != xmsk1)) 3903 warn_constant_check_range_truncated(op, arg, tp, ot); 3904 else if (nv->u.integer != v->u.integer) 3905 warn_constant_check_range_loss(op, arg, tp, ot); 3906 } 3907 3908 /* 3909 * Converts a typed constant to a constant of another type. 3910 * 3911 * op operator which requires conversion 3912 * arg if op is FARG, # of argument 3913 * tp type to which to convert the constant 3914 * nv new constant 3915 * v old constant 3916 */ 3917 void 3918 convert_constant(op_t op, int arg, const type_t *tp, val_t *nv, val_t *v) 3919 { 3920 /* 3921 * TODO: make 'v' const; the name of this function does not suggest 3922 * that it modifies 'v'. 3923 */ 3924 tspec_t ot = v->v_tspec; 3925 tspec_t nt = nv->v_tspec = tp->t_tspec; 3926 bool range_check = false; 3927 3928 if (nt == BOOL) { /* C99 6.3.1.2 */ 3929 nv->v_unsigned_since_c90 = false; 3930 nv->u.integer = is_nonzero_val(v) ? 1 : 0; 3931 return; 3932 } 3933 3934 if (ot == FLOAT || ot == DOUBLE || ot == LDOUBLE) 3935 convert_constant_floating(op, arg, ot, tp, nt, v, nv); 3936 else if (!convert_constant_to_floating(nt, nv, ot, v)) { 3937 range_check = true; /* Check for lost precision. */ 3938 nv->u.integer = v->u.integer; 3939 } 3940 3941 if (allow_trad && allow_c90 && v->v_unsigned_since_c90 && 3942 (is_floating(nt) || ( 3943 (is_integer(nt) && !is_uinteger(nt) && 3944 portable_size_in_bits(nt) > portable_size_in_bits(ot))))) { 3945 /* ANSI C treats constant as unsigned */ 3946 warning(157); 3947 v->v_unsigned_since_c90 = false; 3948 } 3949 3950 if (is_integer(nt)) { 3951 nv->u.integer = convert_integer(nv->u.integer, nt, 3952 tp->t_bitfield ? tp->t_bit_field_width : size_in_bits(nt)); 3953 } 3954 3955 if (range_check && op != CVT) 3956 convert_constant_check_range(ot, tp, nt, op, arg, v, nv); 3957 } 3958 3959 /* 3960 * Create a constant node for sizeof. 3961 */ 3962 tnode_t * 3963 build_sizeof(const type_t *tp) 3964 { 3965 unsigned int size_in_bytes = type_size_in_bits(tp) / CHAR_SIZE; 3966 tnode_t *tn = build_integer_constant(SIZEOF_TSPEC, size_in_bytes); 3967 tn->tn_system_dependent = true; 3968 debug_step("build_sizeof '%s' = %u", type_name(tp), size_in_bytes); 3969 return tn; 3970 } 3971 3972 /* 3973 * Create a constant node for offsetof. 3974 */ 3975 /* ARGSUSED */ /* FIXME: See implementation comments. */ 3976 tnode_t * 3977 build_offsetof(const type_t *tp, const sym_t *sym) 3978 { 3979 3980 if (!is_struct_or_union(tp->t_tspec)) 3981 /* unacceptable operand of '%s' */ 3982 error(111, "offsetof"); 3983 3984 /* FIXME: Don't wrongly use the size of the whole type, use sym. */ 3985 unsigned int offset_in_bytes = type_size_in_bits(tp) / CHAR_SIZE; 3986 tnode_t *tn = build_integer_constant(SIZEOF_TSPEC, offset_in_bytes); 3987 tn->tn_system_dependent = true; 3988 return tn; 3989 } 3990 3991 unsigned int 3992 type_size_in_bits(const type_t *tp) 3993 { 3994 3995 unsigned int elem = 1; 3996 bool flex = false; 3997 lint_assert(tp != NULL); 3998 while (tp->t_tspec == ARRAY) { 3999 flex = true; /* allow c99 flex arrays [] [0] */ 4000 elem *= tp->t_dim; 4001 tp = tp->t_subt; 4002 } 4003 if (elem == 0 && !flex) { 4004 /* cannot take size/alignment of incomplete type */ 4005 error(143); 4006 elem = 1; 4007 } 4008 4009 unsigned int elsz; 4010 switch (tp->t_tspec) { 4011 case VOID: 4012 /* cannot take size/alignment of void */ 4013 error(146); 4014 elsz = 1; 4015 break; 4016 case FUNC: 4017 /* cannot take size/alignment of function type '%s' */ 4018 error(144, type_name(tp)); 4019 elsz = 1; 4020 break; 4021 case STRUCT: 4022 case UNION: 4023 if (is_incomplete(tp)) { 4024 /* cannot take size/alignment of incomplete type */ 4025 error(143); 4026 elsz = 1; 4027 } else { 4028 elsz = tp->t_sou->sou_size_in_bits; 4029 } 4030 break; 4031 case ENUM: 4032 if (is_incomplete(tp)) { 4033 /* cannot take size/alignment of incomplete type */ 4034 warning(143); 4035 } 4036 /* FALLTHROUGH */ 4037 default: 4038 if (tp->t_bitfield) { 4039 /* cannot take size/alignment of bit-field */ 4040 error(145); 4041 } 4042 elsz = size_in_bits(tp->t_tspec); 4043 lint_assert(elsz > 0); 4044 break; 4045 } 4046 4047 return elem * elsz; 4048 } 4049 4050 /* C11 6.5.3.4, GCC */ 4051 tnode_t * 4052 build_alignof(const type_t *tp) 4053 { 4054 if (tp->t_tspec == FUNC) { 4055 /* cannot take size/alignment of function type '%s' */ 4056 error(144, type_name(tp)); 4057 return NULL; 4058 } 4059 if (tp->t_tspec == VOID) { 4060 /* cannot take size/alignment of void */ 4061 error(146); 4062 return NULL; 4063 } 4064 if (is_incomplete(tp)) { 4065 /* cannot take size/alignment of incomplete type */ 4066 error(143); 4067 return NULL; 4068 } 4069 if (tp->t_bitfield) { 4070 /* cannot take size/alignment of bit-field */ 4071 error(145); 4072 return NULL; 4073 } 4074 return build_integer_constant(SIZEOF_TSPEC, 4075 (int64_t)alignment_in_bits(tp) / CHAR_SIZE); 4076 } 4077 4078 static tnode_t * 4079 cast_to_union(tnode_t *otn, type_t *ntp) 4080 { 4081 4082 if (!allow_gcc) { 4083 /* union cast is a GCC extension */ 4084 error(328); 4085 return NULL; 4086 } 4087 4088 for (const sym_t *m = ntp->t_sou->sou_first_member; 4089 m != NULL; m = m->s_next) { 4090 if (types_compatible(m->s_type, otn->tn_type, 4091 false, false, NULL)) { 4092 tnode_t *ntn = expr_alloc_tnode(); 4093 ntn->tn_op = CVT; 4094 ntn->tn_type = ntp; 4095 ntn->tn_cast = true; 4096 ntn->tn_left = otn; 4097 ntn->tn_right = NULL; 4098 return ntn; 4099 } 4100 } 4101 4102 /* type '%s' is not a member of '%s' */ 4103 error(329, type_name(otn->tn_type), type_name(ntp)); 4104 return NULL; 4105 } 4106 4107 /* 4108 * Type casts. 4109 */ 4110 tnode_t * 4111 cast(tnode_t *tn, type_t *tp) 4112 { 4113 4114 if (tn == NULL) 4115 return NULL; 4116 4117 tn = cconv(tn); 4118 4119 lint_assert(tp != NULL); 4120 tspec_t nt = tp->t_tspec; 4121 tspec_t ot = tn->tn_type->t_tspec; 4122 4123 if (nt == VOID) { 4124 /* 4125 * C90 6.3.4, C99 6.5.4p2 and C11 6.5.4p2 allow any type to 4126 * be cast to void. The only other allowed casts are from a 4127 * scalar type to a scalar type. 4128 */ 4129 } else if (nt == UNION) 4130 return cast_to_union(tn, tp); 4131 else if (nt == STRUCT || nt == ARRAY || nt == FUNC) { 4132 /* Casting to a struct is an undocumented GCC extension. */ 4133 if (!(allow_gcc && nt == STRUCT)) 4134 goto invalid_cast; 4135 } else if (is_struct_or_union(ot)) 4136 goto invalid_cast; 4137 else if (ot == VOID) { 4138 /* improper cast of void expression */ 4139 error(148); 4140 return NULL; 4141 } else if (is_integer(nt) && is_scalar(ot)) { 4142 /* ok */ 4143 } else if (is_floating(nt) && is_arithmetic(ot)) { 4144 /* ok */ 4145 } else if (nt == PTR && is_integer(ot)) { 4146 /* ok */ 4147 } else if (nt == PTR && ot == PTR) { 4148 if (!tp->t_subt->t_const && tn->tn_type->t_subt->t_const) { 4149 if (hflag) 4150 /* cast discards 'const' from type '%s' */ 4151 warning(275, type_name(tn->tn_type)); 4152 } 4153 } else 4154 goto invalid_cast; 4155 4156 if (any_query_enabled && types_compatible(tp, tn->tn_type, 4157 false, false, NULL)) { 4158 /* no-op cast from '%s' to '%s' */ 4159 query_message(6, type_name(tn->tn_type), type_name(tp)); 4160 } 4161 4162 tn = convert(CVT, 0, tp, tn); 4163 tn->tn_cast = true; 4164 4165 return tn; 4166 4167 invalid_cast: 4168 /* invalid cast from '%s' to '%s' */ 4169 error(147, type_name(tn->tn_type), type_name(tp)); 4170 return NULL; 4171 } 4172 4173 /* 4174 * Create the node for a function argument. 4175 * All necessary conversions and type checks are done in 4176 * build_function_call because build_function_argument has no 4177 * information about expected argument types. 4178 */ 4179 tnode_t * 4180 build_function_argument(tnode_t *args, tnode_t *arg) 4181 { 4182 /* 4183 * If there was a serious error in the expression for the argument, 4184 * create a dummy argument so the positions of the remaining arguments 4185 * will not change. 4186 */ 4187 if (arg == NULL) 4188 arg = build_integer_constant(INT, 0); 4189 4190 return new_tnode(PUSH, arg->tn_sys, arg->tn_type, arg, args); 4191 } 4192 4193 /* 4194 * Compare the type of an argument with the corresponding type of a 4195 * prototype parameter. If it is a valid combination, but both types 4196 * are not the same, insert a conversion to convert the argument into 4197 * the type of the parameter. 4198 */ 4199 static tnode_t * 4200 check_prototype_argument( 4201 int n, /* pos of arg */ 4202 type_t *tp, /* expected type (from prototype) */ 4203 tnode_t *tn) /* argument */ 4204 { 4205 tnode_t *ln = xcalloc(1, sizeof(*ln)); 4206 ln->tn_type = expr_unqualified_type(tp); 4207 ln->tn_lvalue = true; 4208 if (typeok(FARG, n, ln, tn)) { 4209 bool dowarn; 4210 if (!types_compatible(tp, tn->tn_type, 4211 true, false, (dowarn = false, &dowarn)) || dowarn) 4212 tn = convert(FARG, n, tp, tn); 4213 } 4214 free(ln); 4215 return tn; 4216 } 4217 4218 /* 4219 * Check types of all function arguments and insert conversions, 4220 * if necessary. 4221 */ 4222 static tnode_t * 4223 check_function_arguments(type_t *ftp, tnode_t *args) 4224 { 4225 /* get # of parameters in the prototype */ 4226 int npar = 0; 4227 for (sym_t *asym = ftp->t_args; asym != NULL; asym = asym->s_next) 4228 npar++; 4229 4230 /* get # of arguments in the function call */ 4231 int narg = 0; 4232 for (tnode_t *arg = args; arg != NULL; arg = arg->tn_right) 4233 narg++; 4234 4235 sym_t *asym = ftp->t_args; 4236 if (ftp->t_proto && npar != narg && !(ftp->t_vararg && npar < narg)) { 4237 /* argument mismatch: %d %s passed, %d expected */ 4238 error(150, narg, narg > 1 ? "arguments" : "argument", npar); 4239 asym = NULL; 4240 } 4241 4242 for (int n = 1; n <= narg; n++) { 4243 4244 /* 4245 * The rightmost argument is at the top of the argument 4246 * subtree. 4247 */ 4248 tnode_t *arg = args; 4249 for (int i = narg; i > n; i--, arg = arg->tn_right) 4250 continue; 4251 4252 /* some things which are always not allowed */ 4253 tspec_t at = arg->tn_left->tn_type->t_tspec; 4254 if (at == VOID) { 4255 /* void expressions may not be arguments, arg #%d */ 4256 error(151, n); 4257 return NULL; 4258 } else if (is_struct_or_union(at) && 4259 is_incomplete(arg->tn_left->tn_type)) { 4260 /* argument cannot have unknown size, arg #%d */ 4261 error(152, n); 4262 return NULL; 4263 } else if (is_integer(at) && 4264 arg->tn_left->tn_type->t_is_enum && 4265 is_incomplete(arg->tn_left->tn_type)) { 4266 /* argument cannot have unknown size, arg #%d */ 4267 warning(152, n); 4268 } 4269 4270 /* class conversions (arg in value context) */ 4271 arg->tn_left = cconv(arg->tn_left); 4272 4273 if (asym != NULL) { 4274 arg->tn_left = check_prototype_argument( 4275 n, asym->s_type, arg->tn_left); 4276 } else 4277 arg->tn_left = promote(NOOP, true, arg->tn_left); 4278 arg->tn_type = arg->tn_left->tn_type; 4279 4280 if (asym != NULL) 4281 asym = asym->s_next; 4282 } 4283 4284 return args; 4285 } 4286 4287 /* 4288 * Create the node for a function call. Also check types of 4289 * function arguments and insert conversions, if necessary. 4290 */ 4291 tnode_t * 4292 build_function_call(tnode_t *func, bool sys, tnode_t *args) 4293 { 4294 4295 if (func == NULL) 4296 return NULL; 4297 4298 op_t fcop = func->tn_op == NAME && func->tn_type->t_tspec == FUNC 4299 ? CALL : ICALL; 4300 4301 check_ctype_function_call(func, args); 4302 4303 /* Turn the function name into a pointer to the function. */ 4304 func = cconv(func); 4305 4306 if (func->tn_type->t_tspec != PTR || 4307 func->tn_type->t_subt->t_tspec != FUNC) { 4308 /* cannot call '%s', must be a function */ 4309 error(149, type_name(func->tn_type)); 4310 return NULL; 4311 } 4312 4313 args = check_function_arguments(func->tn_type->t_subt, args); 4314 4315 return new_tnode(fcop, sys, func->tn_type->t_subt->t_subt, func, args); 4316 } 4317 4318 /* 4319 * Return the value of an integral constant expression. 4320 * If the expression is not constant or its type is not an integer 4321 * type, an error message is printed. 4322 */ 4323 val_t * 4324 integer_constant(tnode_t *tn, bool required) 4325 { 4326 4327 if (tn != NULL) 4328 tn = cconv(tn); 4329 if (tn != NULL) 4330 tn = promote(NOOP, false, tn); 4331 4332 val_t *v = xcalloc(1, sizeof(*v)); 4333 4334 if (tn == NULL) { 4335 lint_assert(seen_error); 4336 debug_step("constant node is null; returning 1 instead"); 4337 v->v_tspec = INT; 4338 v->u.integer = 1; 4339 return v; 4340 } 4341 4342 v->v_tspec = tn->tn_type->t_tspec; 4343 4344 if (tn->tn_op == CON) { 4345 lint_assert(tn->tn_type->t_tspec == tn->tn_val.v_tspec); 4346 if (is_integer(tn->tn_val.v_tspec)) { 4347 v->v_unsigned_since_c90 = 4348 tn->tn_val.v_unsigned_since_c90; 4349 v->u.integer = tn->tn_val.u.integer; 4350 return v; 4351 } 4352 v->u.integer = (int64_t)tn->tn_val.u.floating; 4353 } else { 4354 v->u.integer = 1; 4355 } 4356 4357 if (required) 4358 /* integral constant expression expected */ 4359 error(55); 4360 else 4361 /* variable array dimension is a C99/GCC extension */ 4362 c99ism(318); 4363 4364 if (!is_integer(v->v_tspec)) 4365 v->v_tspec = INT; 4366 4367 return v; 4368 } 4369 4370 static bool 4371 is_constcond_false(const tnode_t *tn, tspec_t t) 4372 { 4373 return (t == BOOL || t == INT) && 4374 tn->tn_op == CON && tn->tn_val.u.integer == 0; 4375 } 4376 4377 /* 4378 * Perform some tests on expressions which can't be done in build_binary() 4379 * and functions called by build_binary(). These tests must be done here 4380 * because we need some information about the context in which the operations 4381 * are performed. 4382 * After all tests are performed and dofreeblk is true, expr() frees the 4383 * memory which is used for the expression. 4384 */ 4385 void 4386 expr(tnode_t *tn, bool vctx, bool cond, bool dofreeblk, bool is_do_while) 4387 { 4388 4389 if (tn == NULL) { /* in case of errors */ 4390 expr_free_all(); 4391 return; 4392 } 4393 4394 /* expr() is also called in global initializations */ 4395 if (dcs->d_kind != DLK_EXTERN && !is_do_while) 4396 check_statement_reachable(); 4397 4398 check_expr_misc(tn, vctx, cond, !cond, false, false, false); 4399 if (tn->tn_op == ASSIGN && !tn->tn_parenthesized) { 4400 if (hflag && cond) 4401 /* assignment in conditional context */ 4402 warning(159); 4403 } else if (tn->tn_op == CON) { 4404 if (hflag && cond && !constcond_flag && 4405 !tn->tn_system_dependent && 4406 !(is_do_while && 4407 is_constcond_false(tn, tn->tn_type->t_tspec))) 4408 /* constant in conditional context */ 4409 warning(161); 4410 } 4411 if (!modtab[tn->tn_op].m_has_side_effect) { 4412 /* 4413 * for left operands of COMMA this warning is already 4414 * printed 4415 */ 4416 if (tn->tn_op != COMMA && !vctx && !cond) 4417 check_null_effect(tn); 4418 } 4419 debug_node(tn); 4420 4421 /* free the tree memory */ 4422 if (dofreeblk) 4423 expr_free_all(); 4424 } 4425 4426 /* 4427 * Checks the range of array indices, if possible. 4428 * amper is set if only the address of the element is used. This 4429 * means that the index is allowed to refer to the first element 4430 * after the array. 4431 */ 4432 static void 4433 check_array_index(tnode_t *tn, bool amper) 4434 { 4435 const tnode_t *ln = tn->tn_left; 4436 const tnode_t *rn = tn->tn_right; 4437 4438 /* We can only check constant indices. */ 4439 if (rn->tn_op != CON) 4440 return; 4441 4442 /* Return if the left node does not stem from an array. */ 4443 if (ln->tn_op != ADDR) 4444 return; 4445 if (ln->tn_left->tn_op != STRING && ln->tn_left->tn_op != NAME) 4446 return; 4447 if (ln->tn_left->tn_type->t_tspec != ARRAY) 4448 return; 4449 4450 /* 4451 * For incomplete array types, we can print a warning only if 4452 * the index is negative. 4453 */ 4454 if (is_incomplete(ln->tn_left->tn_type) && rn->tn_val.u.integer >= 0) 4455 return; 4456 4457 /* Get the size of one array element */ 4458 int elsz = length_in_bits(ln->tn_type->t_subt, NULL); 4459 if (elsz == 0) 4460 return; 4461 elsz /= CHAR_SIZE; 4462 4463 /* Change the unit of the index from bytes to element size. */ 4464 int64_t con = is_uinteger(rn->tn_type->t_tspec) 4465 ? (int64_t)((uint64_t)rn->tn_val.u.integer / elsz) 4466 : rn->tn_val.u.integer / elsz; 4467 4468 int dim = ln->tn_left->tn_type->t_dim + (amper ? 1 : 0); 4469 4470 if (!is_uinteger(rn->tn_type->t_tspec) && con < 0) { 4471 /* array subscript cannot be negative: %ld */ 4472 warning(167, (long)con); 4473 } else if (dim > 0 && (uint64_t)con >= (uint64_t)dim) { 4474 /* array subscript cannot be > %d: %ld */ 4475 warning(168, dim - 1, (long)con); 4476 } 4477 } 4478 4479 static void 4480 check_expr_addr(const tnode_t *ln, bool szof, bool fcall) 4481 { 4482 /* XXX: Taking warn_about_unreachable into account here feels wrong. */ 4483 if (ln->tn_op == NAME && (reached || !warn_about_unreachable)) { 4484 if (!szof) 4485 mark_as_set(ln->tn_sym); 4486 mark_as_used(ln->tn_sym, fcall, szof); 4487 } 4488 if (ln->tn_op == INDIR && ln->tn_left->tn_op == PLUS) 4489 /* check the range of array indices */ 4490 check_array_index(ln->tn_left, true); 4491 } 4492 4493 static void 4494 check_expr_load(const tnode_t *ln) 4495 { 4496 if (ln->tn_op == INDIR && ln->tn_left->tn_op == PLUS) 4497 /* check the range of array indices */ 4498 check_array_index(ln->tn_left, false); 4499 } 4500 4501 /* 4502 * If there is an asm statement in one of the compound statements around, 4503 * there may be other side effects, so don't warn. 4504 */ 4505 static bool 4506 is_asm_around(void) 4507 { 4508 for (decl_level *dl = dcs; dl != NULL; dl = dl->d_enclosing) 4509 if (dl->d_asm) 4510 return true; 4511 return false; 4512 } 4513 4514 static void 4515 check_expr_side_effect(const tnode_t *ln, bool szof) 4516 { 4517 4518 /* XXX: Taking warn_about_unreachable into account here feels wrong. */ 4519 if (ln->tn_op == NAME && (reached || !warn_about_unreachable)) { 4520 scl_t sc = ln->tn_sym->s_scl; 4521 if (sc != EXTERN && sc != STATIC && 4522 !ln->tn_sym->s_set && !szof && !is_asm_around()) { 4523 /* '%s' may be used before set */ 4524 warning(158, ln->tn_sym->s_name); 4525 mark_as_set(ln->tn_sym); 4526 } 4527 mark_as_used(ln->tn_sym, false, false); 4528 } 4529 } 4530 4531 static void 4532 check_expr_assign(const tnode_t *ln, bool szof) 4533 { 4534 /* XXX: Taking warn_about_unreachable into account here feels wrong. */ 4535 if (ln->tn_op == NAME && !szof && (reached || !warn_about_unreachable)) { 4536 mark_as_set(ln->tn_sym); 4537 if (ln->tn_sym->s_scl == EXTERN) 4538 outusg(ln->tn_sym); 4539 } 4540 if (ln->tn_op == INDIR && ln->tn_left->tn_op == PLUS) 4541 /* check the range of array indices */ 4542 check_array_index(ln->tn_left, false); 4543 } 4544 4545 static void 4546 check_expr_call(const tnode_t *tn, const tnode_t *ln, 4547 bool szof, bool vctx, bool cond, bool retval_discarded) 4548 { 4549 lint_assert(ln->tn_op == ADDR); 4550 lint_assert(ln->tn_left->tn_op == NAME); 4551 if (!szof && !is_compiler_builtin(ln->tn_left->tn_sym->s_name)) 4552 outcall(tn, vctx || cond, retval_discarded); 4553 } 4554 4555 static bool 4556 check_expr_op(const tnode_t *tn, op_t op, const tnode_t *ln, 4557 bool szof, bool fcall, bool vctx, bool cond, 4558 bool retval_discarded, bool eqwarn) 4559 { 4560 switch (op) { 4561 case ADDR: 4562 check_expr_addr(ln, szof, fcall); 4563 break; 4564 case LOAD: 4565 check_expr_load(ln); 4566 /* FALLTHROUGH */ 4567 case PUSH: 4568 case INCBEF: 4569 case DECBEF: 4570 case INCAFT: 4571 case DECAFT: 4572 case ADDASS: 4573 case SUBASS: 4574 case MULASS: 4575 case DIVASS: 4576 case MODASS: 4577 case ANDASS: 4578 case ORASS: 4579 case XORASS: 4580 case SHLASS: 4581 case SHRASS: 4582 case REAL: 4583 case IMAG: 4584 check_expr_side_effect(ln, szof); 4585 break; 4586 case ASSIGN: 4587 check_expr_assign(ln, szof); 4588 break; 4589 case CALL: 4590 check_expr_call(tn, ln, szof, vctx, cond, retval_discarded); 4591 break; 4592 case EQ: 4593 if (hflag && eqwarn) 4594 /* operator '==' found where '=' was expected */ 4595 warning(160); 4596 break; 4597 case CON: 4598 case NAME: 4599 case STRING: 4600 return false; 4601 default: 4602 break; 4603 } 4604 return true; 4605 } 4606 4607 /* 4608 * vctx ??? 4609 * cond whether the expression is a condition that 4610 * will be compared with 0 4611 * eqwarn whether the operator '==' might be a 4612 * misspelled '=' 4613 * fcall whether the expression is a function call 4614 * retval_discarded whether the return value of a function call 4615 * is discarded; such calls will be analyzed by 4616 * lint2 in messages 4, 8 and 9 4617 * szof whether the expression is part of a sizeof 4618 * expression, which means that its value is 4619 * discarded since only the type is relevant 4620 */ 4621 void 4622 check_expr_misc(const tnode_t *tn, bool vctx, bool cond, 4623 bool eqwarn, bool fcall, bool retval_discarded, bool szof) 4624 { 4625 4626 if (tn == NULL) 4627 return; 4628 4629 tnode_t *ln = tn->tn_left; 4630 tnode_t *rn = tn->tn_right; 4631 op_t op = tn->tn_op; 4632 const mod_t *mp = &modtab[op]; 4633 4634 if (!check_expr_op(tn, op, ln, 4635 szof, fcall, vctx, cond, retval_discarded, eqwarn)) 4636 return; 4637 4638 bool cvctx = mp->m_value_context; 4639 bool ccond = mp->m_compares_with_zero; 4640 bool eq = mp->m_warn_if_operand_eq && 4641 !ln->tn_parenthesized && 4642 rn != NULL && !rn->tn_parenthesized; 4643 4644 /* 4645 * values of operands of ':' are not used if the type of at least 4646 * one of the operands (for gcc compatibility) is void 4647 * XXX test/value context of QUEST should probably be used as 4648 * context for both operands of COLON 4649 */ 4650 if (op == COLON && tn->tn_type->t_tspec == VOID) 4651 cvctx = ccond = false; 4652 bool discard = op == CVT && tn->tn_type->t_tspec == VOID; 4653 check_expr_misc(ln, cvctx, ccond, eq, op == CALL, discard, szof); 4654 4655 switch (op) { 4656 case PUSH: 4657 if (rn != NULL) 4658 check_expr_misc(rn, false, false, eq, false, false, 4659 szof); 4660 break; 4661 case LOGAND: 4662 case LOGOR: 4663 check_expr_misc(rn, false, true, eq, false, false, szof); 4664 break; 4665 case COLON: 4666 check_expr_misc(rn, cvctx, ccond, eq, false, false, szof); 4667 break; 4668 case COMMA: 4669 check_expr_misc(rn, vctx, cond, false, false, false, szof); 4670 break; 4671 default: 4672 if (mp->m_binary) 4673 check_expr_misc(rn, true, false, eq, false, false, 4674 szof); 4675 break; 4676 } 4677 } 4678 4679 /* 4680 * Return whether the expression can be used for static initialization. 4681 * 4682 * Constant initialization expressions must be constant or an address 4683 * of a static object with an optional offset. In the first case, 4684 * the result is returned in *offsp. In the second case, the static 4685 * object is returned in *symp and the offset in *offsp. 4686 * 4687 * The expression can consist of PLUS, MINUS, ADDR, NAME, STRING and 4688 * CON. Type conversions are allowed if they do not change binary 4689 * representation (including width). 4690 * 4691 * C99 6.6 "Constant expressions" 4692 * C99 6.7.8p4 restricts initializers for static storage duration 4693 */ 4694 bool 4695 constant_addr(const tnode_t *tn, const sym_t **symp, ptrdiff_t *offsp) 4696 { 4697 const sym_t *sym; 4698 ptrdiff_t offs1, offs2; 4699 tspec_t t, ot; 4700 4701 switch (tn->tn_op) { 4702 case MINUS: 4703 if (tn->tn_right->tn_op == CVT) 4704 return constant_addr(tn->tn_right, symp, offsp); 4705 else if (tn->tn_right->tn_op != CON) 4706 return false; 4707 /* FALLTHROUGH */ 4708 case PLUS: 4709 offs1 = offs2 = 0; 4710 if (tn->tn_left->tn_op == CON) { 4711 offs1 = (ptrdiff_t)tn->tn_left->tn_val.u.integer; 4712 if (!constant_addr(tn->tn_right, &sym, &offs2)) 4713 return false; 4714 } else if (tn->tn_right->tn_op == CON) { 4715 offs2 = (ptrdiff_t)tn->tn_right->tn_val.u.integer; 4716 if (tn->tn_op == MINUS) 4717 offs2 = -offs2; 4718 if (!constant_addr(tn->tn_left, &sym, &offs1)) 4719 return false; 4720 } else { 4721 return false; 4722 } 4723 *symp = sym; 4724 *offsp = offs1 + offs2; 4725 return true; 4726 case ADDR: 4727 if (tn->tn_left->tn_op == NAME) { 4728 *symp = tn->tn_left->tn_sym; 4729 *offsp = 0; 4730 return true; 4731 } else { 4732 /* 4733 * If this were the front end of a compiler, we 4734 * would return a label instead of 0, at least if 4735 * 'tn->tn_left->tn_op == STRING'. 4736 */ 4737 *symp = NULL; 4738 *offsp = 0; 4739 return true; 4740 } 4741 case CVT: 4742 t = tn->tn_type->t_tspec; 4743 ot = tn->tn_left->tn_type->t_tspec; 4744 if ((!is_integer(t) && t != PTR) || 4745 (!is_integer(ot) && ot != PTR)) { 4746 return false; 4747 } 4748 #if 0 4749 /* 4750 * consider: 4751 * struct foo { 4752 * unsigned char a; 4753 * } f = { 4754 * (unsigned char)(unsigned long) 4755 * (&(((struct foo *)0)->a)) 4756 * }; 4757 * since psize(unsigned long) != psize(unsigned char), 4758 * this fails. 4759 */ 4760 else if (psize(t) != psize(ot)) 4761 return -1; 4762 #endif 4763 return constant_addr(tn->tn_left, symp, offsp); 4764 default: 4765 return false; 4766 } 4767 } 4768 4769 /* Append s2 to s1, then free s2. */ 4770 strg_t * 4771 cat_strings(strg_t *s1, strg_t *s2) 4772 { 4773 4774 if (s1->st_char != s2->st_char) { 4775 /* cannot concatenate wide and regular string literals */ 4776 error(292); 4777 return s1; 4778 } 4779 4780 size_t len1 = s1->st_len; 4781 size_t len2 = s2->st_len; 4782 size_t chsize = s1->st_char ? sizeof(char) : sizeof(wchar_t); 4783 size_t size1 = len1 * chsize; 4784 size_t size2 = (len2 + 1) * chsize; 4785 s1->st_mem = xrealloc(s1->st_mem, size1 + size2); 4786 memcpy((char *)s1->st_mem + size1, s2->st_mem, size2); 4787 free(s2->st_mem); 4788 4789 s1->st_len = len1 + len2; 4790 free(s2); 4791 4792 return s1; 4793 } 4794 4795 4796 typedef struct stmt_expr { 4797 memory_pool se_mem; 4798 sym_t *se_sym; 4799 struct stmt_expr *se_enclosing; 4800 } stmt_expr; 4801 4802 static stmt_expr *stmt_exprs; 4803 4804 void 4805 begin_statement_expr(void) 4806 { 4807 stmt_expr *se = xmalloc(sizeof(*se)); 4808 se->se_mem = expr_save_memory(); 4809 se->se_sym = NULL; 4810 se->se_enclosing = stmt_exprs; 4811 stmt_exprs = se; 4812 } 4813 4814 void 4815 do_statement_expr(tnode_t *tn) 4816 { 4817 block_level--; 4818 mem_block_level--; 4819 stmt_exprs->se_sym = tn != NULL 4820 ? mktempsym(block_dup_type(tn->tn_type)) 4821 : NULL; /* after a syntax error */ 4822 mem_block_level++; 4823 block_level++; 4824 /* ({ }) is a GCC extension */ 4825 gnuism(320); 4826 } 4827 4828 tnode_t * 4829 end_statement_expr(void) 4830 { 4831 stmt_expr *se = stmt_exprs; 4832 if (se->se_sym == NULL) 4833 return NULL; /* after a syntax error */ 4834 tnode_t *tn = build_name(se->se_sym, false); 4835 (void)expr_save_memory(); /* leak */ 4836 expr_restore_memory(se->se_mem); 4837 stmt_exprs = se->se_enclosing; 4838 free(se); 4839 return tn; 4840 } 4841
Indexes created Tue Sep 23 23:09:58 GMT 2025