tree.c revision 1.567
1 /* $NetBSD: tree.c,v 1.567 2023/07/15 12:24:57 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 1.567 2023/07/15 12:24:57 rillig Exp $"); 41 #endif 42 43 #include <float.h> 44 #include <limits.h> 45 #include <math.h> 46 #include <signal.h> 47 #include <stdlib.h> 48 #include <string.h> 49 50 #include "lint1.h" 51 52 53 typedef struct integer_constraints { 54 int64_t smin; /* signed minimum */ 55 int64_t smax; /* signed maximum */ 56 uint64_t umin; /* unsigned minimum */ 57 uint64_t umax; /* unsigned maximum */ 58 uint64_t bset; /* bits that are definitely set */ 59 uint64_t bclr; /* bits that are definitely clear */ 60 } integer_constraints; 61 62 63 static uint64_t 64 u64_fill_right(uint64_t x) 65 { 66 x |= x >> 1; 67 x |= x >> 2; 68 x |= x >> 4; 69 x |= x >> 8; 70 x |= x >> 16; 71 x |= x >> 32; 72 return x; 73 } 74 75 static bool 76 str_ends_with(const char *haystack, const char *needle) 77 { 78 size_t hlen = strlen(haystack); 79 size_t nlen = strlen(needle); 80 81 return nlen <= hlen && 82 memcmp(haystack + hlen - nlen, needle, nlen) == 0; 83 } 84 85 static unsigned 86 width_in_bits(const type_t *tp) 87 { 88 89 lint_assert(is_integer(tp->t_tspec)); 90 return tp->t_bitfield 91 ? tp->t_bit_field_width 92 : size_in_bits(tp->t_tspec); 93 } 94 95 static int 96 portable_rank_cmp(tspec_t t1, tspec_t t2) { 97 const ttab_t *p1 = type_properties(t1), *p2 = type_properties(t2); 98 lint_assert(p1->tt_rank_kind == p2->tt_rank_kind); 99 lint_assert(p1->tt_rank_value > 0); 100 lint_assert(p2->tt_rank_value > 0); 101 return (int)p1->tt_rank_value - (int)p2->tt_rank_value; 102 } 103 104 static bool 105 ic_maybe_signed(const type_t *tp, const integer_constraints *ic) 106 { 107 return !is_uinteger(tp->t_tspec) && ic->bclr >> 63 == 0; 108 } 109 110 static integer_constraints 111 ic_any(const type_t *tp) 112 { 113 integer_constraints c; 114 115 uint64_t vbits = value_bits(width_in_bits(tp)); 116 if (is_uinteger(tp->t_tspec)) { 117 c.smin = INT64_MIN; 118 c.smax = INT64_MAX; 119 c.umin = 0; 120 c.umax = vbits; 121 c.bset = 0; 122 c.bclr = ~c.umax; 123 } else { 124 c.smin = (int64_t)-1 - (int64_t)(vbits >> 1); 125 c.smax = (int64_t)(vbits >> 1); 126 c.umin = 0; 127 c.umax = UINT64_MAX; 128 c.bset = 0; 129 c.bclr = 0; 130 } 131 return c; 132 } 133 134 static integer_constraints 135 ic_con(const type_t *tp, const val_t *v) 136 { 137 integer_constraints c; 138 139 lint_assert(is_integer(tp->t_tspec)); 140 int64_t si = v->u.integer; 141 uint64_t ui = (uint64_t)si; 142 c.smin = si; 143 c.smax = si; 144 c.umin = ui; 145 c.umax = ui; 146 c.bset = ui; 147 c.bclr = ~ui; 148 return c; 149 } 150 151 static integer_constraints 152 ic_cvt(const type_t *ntp, const type_t *otp, integer_constraints a) 153 { 154 unsigned nw = width_in_bits(ntp); 155 unsigned ow = width_in_bits(otp); 156 bool nu = is_uinteger(ntp->t_tspec); 157 bool ou = is_uinteger(otp->t_tspec); 158 159 if (nw >= ow && nu == ou) 160 return a; 161 if (nw > ow && ou) 162 return a; 163 return ic_any(ntp); 164 } 165 166 static integer_constraints 167 ic_bitand(integer_constraints a, integer_constraints b) 168 { 169 integer_constraints c; 170 171 c.smin = INT64_MIN; 172 c.smax = INT64_MAX; 173 c.umin = 0; 174 c.umax = UINT64_MAX; 175 c.bset = a.bset & b.bset; 176 c.bclr = a.bclr | b.bclr; 177 return c; 178 } 179 180 static integer_constraints 181 ic_bitor(integer_constraints a, integer_constraints b) 182 { 183 integer_constraints c; 184 185 c.smin = INT64_MIN; 186 c.smax = INT64_MAX; 187 c.umin = 0; 188 c.umax = UINT64_MAX; 189 c.bset = a.bset | b.bset; 190 c.bclr = a.bclr & b.bclr; 191 return c; 192 } 193 194 static integer_constraints 195 ic_mod(const type_t *tp, integer_constraints a, integer_constraints b) 196 { 197 integer_constraints c; 198 199 if (ic_maybe_signed(tp, &a) || ic_maybe_signed(tp, &b)) 200 return ic_any(tp); 201 202 c.smin = INT64_MIN; 203 c.smax = INT64_MAX; 204 c.umin = 0; 205 c.umax = b.umax - 1; 206 c.bset = 0; 207 c.bclr = ~u64_fill_right(c.umax); 208 return c; 209 } 210 211 static integer_constraints 212 ic_shl(const type_t *tp, integer_constraints a, integer_constraints b) 213 { 214 integer_constraints c; 215 unsigned int amount; 216 217 if (ic_maybe_signed(tp, &a)) 218 return ic_any(tp); 219 220 if (b.smin == b.smax && b.smin >= 0 && b.smin < 64) 221 amount = (unsigned int)b.smin; 222 else if (b.umin == b.umax && b.umin < 64) 223 amount = (unsigned int)b.umin; 224 else 225 return ic_any(tp); 226 227 c.smin = INT64_MIN; 228 c.smax = INT64_MAX; 229 c.umin = 0; 230 c.umax = UINT64_MAX; 231 c.bset = a.bset << amount; 232 c.bclr = a.bclr << amount | (((uint64_t)1 << amount) - 1); 233 return c; 234 } 235 236 static integer_constraints 237 ic_shr(const type_t *tp, integer_constraints a, integer_constraints b) 238 { 239 integer_constraints c; 240 unsigned int amount; 241 242 if (ic_maybe_signed(tp, &a)) 243 return ic_any(tp); 244 245 if (b.smin == b.smax && b.smin >= 0 && b.smin < 64) 246 amount = (unsigned int)b.smin; 247 else if (b.umin == b.umax && b.umin < 64) 248 amount = (unsigned int)b.umin; 249 else 250 return ic_any(tp); 251 252 c.smin = INT64_MIN; 253 c.smax = INT64_MAX; 254 c.umin = 0; 255 c.umax = UINT64_MAX; 256 c.bset = a.bset >> amount; 257 c.bclr = a.bclr >> amount | ~(~(uint64_t)0 >> amount); 258 return c; 259 } 260 261 static integer_constraints 262 ic_cond(integer_constraints a, integer_constraints b) 263 { 264 integer_constraints c; 265 266 c.smin = a.smin < b.smin ? a.smin : b.smin; 267 c.smax = a.smax > b.smax ? a.smax : b.smax; 268 c.umin = a.umin < b.umin ? a.umin : b.umin; 269 c.umax = a.umax > b.umax ? a.umax : b.umax; 270 c.bset = a.bset | b.bset; 271 c.bclr = a.bclr & b.bclr; 272 return c; 273 } 274 275 static integer_constraints 276 ic_expr(const tnode_t *tn) 277 { 278 integer_constraints lc, rc; 279 280 lint_assert(is_integer(tn->tn_type->t_tspec)); 281 282 switch (tn->tn_op) { 283 case CON: 284 return ic_con(tn->tn_type, &tn->tn_val); 285 case CVT: 286 if (!is_integer(tn->tn_left->tn_type->t_tspec)) 287 return ic_any(tn->tn_type); 288 lc = ic_expr(tn->tn_left); 289 return ic_cvt(tn->tn_type, tn->tn_left->tn_type, lc); 290 case MOD: 291 lc = ic_expr(before_conversion(tn->tn_left)); 292 rc = ic_expr(before_conversion(tn->tn_right)); 293 return ic_mod(tn->tn_type, lc, rc); 294 case SHL: 295 lc = ic_expr(tn->tn_left); 296 rc = ic_expr(tn->tn_right); 297 return ic_shl(tn->tn_type, lc, rc); 298 case SHR: 299 lc = ic_expr(tn->tn_left); 300 rc = ic_expr(tn->tn_right); 301 return ic_shr(tn->tn_type, lc, rc); 302 case BITAND: 303 lc = ic_expr(tn->tn_left); 304 rc = ic_expr(tn->tn_right); 305 return ic_bitand(lc, rc); 306 case BITOR: 307 lc = ic_expr(tn->tn_left); 308 rc = ic_expr(tn->tn_right); 309 return ic_bitor(lc, rc); 310 case QUEST: 311 lc = ic_expr(tn->tn_right->tn_left); 312 rc = ic_expr(tn->tn_right->tn_right); 313 return ic_cond(lc, rc); 314 default: 315 return ic_any(tn->tn_type); 316 } 317 } 318 319 /* Build 'pointer to tp', 'array of tp' or 'function returning tp'. */ 320 type_t * 321 block_derive_type(type_t *tp, tspec_t t) 322 { 323 type_t *tp2; 324 325 tp2 = block_zero_alloc(sizeof(*tp2)); 326 tp2->t_tspec = t; 327 tp2->t_subt = tp; 328 return tp2; 329 } 330 331 /* 332 * Derive 'pointer to tp' or 'function returning tp'. 333 * The memory is freed at the end of the current expression. 334 */ 335 type_t * 336 expr_derive_type(type_t *tp, tspec_t t) 337 { 338 type_t *tp2; 339 340 tp2 = expr_zero_alloc(sizeof(*tp2)); 341 tp2->t_tspec = t; 342 tp2->t_subt = tp; 343 return tp2; 344 } 345 346 /* Create an expression from a unary or binary operator and its operands. */ 347 static tnode_t * 348 build_op(op_t op, bool sys, type_t *type, tnode_t *ln, tnode_t *rn) 349 { 350 351 tnode_t *ntn = expr_alloc_tnode(); 352 ntn->tn_op = op; 353 ntn->tn_type = type; 354 ntn->tn_sys = sys; 355 ntn->tn_left = ln; 356 ntn->tn_right = rn; 357 358 if (op == INDIR || op == FSEL) { 359 lint_assert(ln->tn_type->t_tspec == PTR); 360 tspec_t t = ln->tn_type->t_subt->t_tspec; 361 ntn->tn_lvalue = t != FUNC && t != VOID; 362 } 363 364 return ntn; 365 } 366 367 tnode_t * 368 build_constant(type_t *tp, val_t *v) 369 { 370 371 tnode_t *n = expr_alloc_tnode(); 372 n->tn_op = CON; 373 n->tn_type = tp; 374 n->tn_val = *v; 375 n->tn_val.v_tspec = tp->t_tspec; 376 free(v); 377 return n; 378 } 379 380 static tnode_t * 381 build_integer_constant(tspec_t t, int64_t si) 382 { 383 384 tnode_t *n = expr_alloc_tnode(); 385 n->tn_op = CON; 386 n->tn_type = gettyp(t); 387 n->tn_val.v_tspec = t; 388 n->tn_val.v_unsigned_since_c90 = false; 389 n->tn_val.v_char_constant = false; 390 n->tn_val.u.integer = si; 391 return n; 392 } 393 394 static void 395 fallback_symbol(sym_t *sym) 396 { 397 398 if (Tflag && fallback_symbol_strict_bool(sym)) 399 return; 400 401 if (block_level > 0 && (strcmp(sym->s_name, "__FUNCTION__") == 0 || 402 strcmp(sym->s_name, "__PRETTY_FUNCTION__") == 0)) { 403 /* __FUNCTION__/__PRETTY_FUNCTION__ is a GCC extension */ 404 gnuism(316); 405 // XXX: Should probably be ARRAY instead of PTR. 406 sym->s_type = block_derive_type(gettyp(CHAR), PTR); 407 sym->s_type->t_const = true; 408 return; 409 } 410 411 if (block_level > 0 && strcmp(sym->s_name, "__func__") == 0) { 412 if (!allow_c99) 413 /* __func__ is a C99 feature */ 414 warning(317); 415 /* C11 6.4.2.2 */ 416 sym->s_type = block_derive_type(gettyp(CHAR), ARRAY); 417 sym->s_type->t_const = true; 418 sym->s_type->t_dim = (int)strlen(funcsym->s_name) + 1; 419 return; 420 } 421 422 /* '%s' undefined */ 423 error(99, sym->s_name); 424 } 425 426 /* 427 * Functions that are predeclared by GCC or other compilers can be called 428 * with arbitrary arguments. Since lint usually runs after a successful 429 * compilation, it's the compiler's job to catch any errors. 430 */ 431 bool 432 is_compiler_builtin(const char *name) 433 { 434 /* https://gcc.gnu.org/onlinedocs/gcc/C-Extensions.html */ 435 if (allow_gcc) { 436 if (strncmp(name, "__atomic_", 9) == 0 || 437 strncmp(name, "__builtin_", 10) == 0 || 438 strcmp(name, "alloca") == 0 || 439 /* obsolete but still in use, as of 2021 */ 440 strncmp(name, "__sync_", 7) == 0) 441 return true; 442 } 443 444 /* https://software.intel.com/sites/landingpage/IntrinsicsGuide/ */ 445 if (strncmp(name, "_mm_", 4) == 0) 446 return true; 447 448 return false; 449 } 450 451 /* https://gcc.gnu.org/onlinedocs/gcc/Integer-Overflow-Builtins.html */ 452 static bool 453 is_gcc_bool_builtin(const char *name) 454 { 455 return strncmp(name, "__builtin_", 10) == 0 && 456 (str_ends_with(name, "_overflow") || 457 str_ends_with(name, "_overflow_p")); 458 } 459 460 static void 461 build_name_call(sym_t *sym) 462 { 463 464 if (is_compiler_builtin(sym->s_name)) { 465 /* 466 * Do not warn about these, just assume that 467 * they are regular functions compatible with 468 * non-prototype calling conventions. 469 */ 470 if (allow_gcc && is_gcc_bool_builtin(sym->s_name)) 471 sym->s_type = gettyp(BOOL); 472 } else if (allow_c99) { 473 /* function '%s' implicitly declared to return int */ 474 error(215, sym->s_name); 475 } else if (!allow_trad) { 476 /* function '%s' implicitly declared to return int */ 477 warning(215, sym->s_name); 478 } 479 480 /* XXX if !allow_c90, the symbol should be exported to level 0 */ 481 sym->s_type = block_derive_type(sym->s_type, FUNC); 482 } 483 484 /* Create a node for a name (symbol table entry). */ 485 tnode_t * 486 build_name(sym_t *sym, bool is_funcname) 487 { 488 489 if (sym->s_scl == NOSCL && !in_gcc_attribute) { 490 sym->s_scl = EXTERN; 491 sym->s_def = DECL; 492 if (is_funcname) 493 build_name_call(sym); 494 else 495 fallback_symbol(sym); 496 } 497 498 lint_assert(sym->s_kind == FVFT || sym->s_kind == FMEMBER); 499 500 tnode_t *n = expr_alloc_tnode(); 501 n->tn_type = sym->s_type; 502 if (sym->s_scl == BOOL_CONST) { 503 n->tn_op = CON; 504 n->tn_val.v_tspec = BOOL; 505 n->tn_val.v_unsigned_since_c90 = false; 506 n->tn_val.v_char_constant = false; 507 n->tn_val.u.integer = sym->u.s_bool_constant ? 1 : 0; 508 } else if (sym->s_scl == ENUM_CONST) { 509 n->tn_op = CON; 510 n->tn_val.v_tspec = INT; /* ENUM is in n->tn_type */ 511 n->tn_val.v_unsigned_since_c90 = false; 512 n->tn_val.v_char_constant = false; 513 n->tn_val.u.integer = sym->u.s_enum_constant; 514 } else { 515 n->tn_op = NAME; 516 n->tn_sym = sym; 517 if (sym->s_kind == FVFT && sym->s_type->t_tspec != FUNC) 518 n->tn_lvalue = true; 519 } 520 521 return n; 522 } 523 524 tnode_t * 525 build_string(strg_t *strg) 526 { 527 size_t len = strg->st_len; 528 529 type_t *tp = expr_zero_alloc(sizeof(*tp)); 530 tp->t_tspec = ARRAY; 531 tp->t_subt = gettyp(strg->st_char ? CHAR : WCHAR_TSPEC); 532 tp->t_dim = (int)(len + 1); 533 534 tnode_t *n = expr_alloc_tnode(); 535 n->tn_op = STRING; 536 n->tn_type = tp; 537 n->tn_lvalue = true; 538 539 n->tn_string = expr_zero_alloc(sizeof(*n->tn_string)); 540 n->tn_string->st_char = strg->st_char; 541 n->tn_string->st_len = len; 542 543 size_t chsize = strg->st_char ? sizeof(char) : sizeof(wchar_t); 544 size_t size = (len + 1) * chsize; 545 n->tn_string->st_mem = expr_zero_alloc(size); 546 (void)memcpy(n->tn_string->st_mem, strg->st_mem, size); 547 free(strg->st_mem); 548 free(strg); 549 550 return n; 551 } 552 553 tnode_t * 554 build_generic_selection(const tnode_t *expr, 555 struct generic_association *sel) 556 { 557 tnode_t *default_result = NULL; 558 559 for (; sel != NULL; sel = sel->ga_prev) { 560 if (expr != NULL && 561 types_compatible(sel->ga_arg, expr->tn_type, 562 false, false, NULL)) 563 return sel->ga_result; 564 else if (sel->ga_arg == NULL) 565 default_result = sel->ga_result; 566 } 567 return default_result; 568 } 569 570 static bool 571 is_out_of_char_range(const tnode_t *tn) 572 { 573 return tn->tn_op == CON && 574 !tn->tn_val.v_char_constant && 575 !(0 <= tn->tn_val.u.integer && 576 tn->tn_val.u.integer < 1 << (CHAR_SIZE - 1)); 577 } 578 579 static void 580 check_integer_comparison(op_t op, tnode_t *ln, tnode_t *rn) 581 { 582 583 tspec_t lt = ln->tn_type->t_tspec; 584 tspec_t rt = rn->tn_type->t_tspec; 585 586 if (ln->tn_op != CON && rn->tn_op != CON) 587 return; 588 589 if (!is_integer(lt) || !is_integer(rt)) 590 return; 591 592 if (any_query_enabled && !in_system_header) { 593 if (lt == CHAR && rn->tn_op == CON && 594 !rn->tn_val.v_char_constant) { 595 /* comparison '%s' of 'char' with plain integer %d */ 596 query_message(14, 597 op_name(op), (int)rn->tn_val.u.integer); 598 } 599 if (rt == CHAR && ln->tn_op == CON && 600 !ln->tn_val.v_char_constant) { 601 /* comparison '%s' of 'char' with plain integer %d */ 602 query_message(14, 603 op_name(op), (int)ln->tn_val.u.integer); 604 } 605 } 606 607 if (hflag || pflag) { 608 if (lt == CHAR && is_out_of_char_range(rn)) { 609 char buf[128]; 610 (void)snprintf(buf, sizeof(buf), "%s %d", 611 op_name(op), (int)rn->tn_val.u.integer); 612 /* nonportable character comparison '%s' */ 613 warning(230, buf); 614 return; 615 } 616 if (rt == CHAR && is_out_of_char_range(ln)) { 617 char buf[128]; 618 (void)snprintf(buf, sizeof(buf), "%d %s ?", 619 (int)ln->tn_val.u.integer, op_name(op)); 620 /* nonportable character comparison '%s' */ 621 warning(230, buf); 622 return; 623 } 624 } 625 626 if (is_uinteger(lt) && !is_uinteger(rt) && 627 rn->tn_op == CON && rn->tn_val.u.integer <= 0) { 628 if (rn->tn_val.u.integer < 0) { 629 /* operator '%s' compares '%s' with '%s' */ 630 warning(162, op_name(op), 631 type_name(ln->tn_type), "negative constant"); 632 } else if (op == LT || op == GE) { 633 /* operator '%s' compares '%s' with '%s' */ 634 warning(162, op_name(op), type_name(ln->tn_type), "0"); 635 } 636 return; 637 } 638 if (is_uinteger(rt) && !is_uinteger(lt) && 639 ln->tn_op == CON && ln->tn_val.u.integer <= 0) { 640 if (ln->tn_val.u.integer < 0) { 641 /* operator '%s' compares '%s' with '%s' */ 642 warning(162, op_name(op), 643 "negative constant", type_name(rn->tn_type)); 644 } else if (op == GT || op == LE) { 645 /* operator '%s' compares '%s' with '%s' */ 646 warning(162, op_name(op), "0", type_name(rn->tn_type)); 647 } 648 return; 649 } 650 } 651 652 static const tspec_t arith_rank[] = { 653 LDOUBLE, DOUBLE, FLOAT, 654 #ifdef INT128_SIZE 655 UINT128, INT128, 656 #endif 657 ULLONG, LLONG, 658 ULONG, LONG, 659 UINT, INT, 660 }; 661 662 /* Keep unsigned in traditional C */ 663 static tspec_t 664 usual_arithmetic_conversion_trad(tspec_t lt, tspec_t rt) 665 { 666 667 size_t i; 668 for (i = 0; arith_rank[i] != INT; i++) 669 if (lt == arith_rank[i] || rt == arith_rank[i]) 670 break; 671 672 tspec_t t = arith_rank[i]; 673 if (is_uinteger(lt) || is_uinteger(rt)) 674 if (is_integer(t) && !is_uinteger(t)) 675 return unsigned_type(t); 676 return t; 677 } 678 679 static tspec_t 680 usual_arithmetic_conversion_c90(tspec_t lt, tspec_t rt) 681 { 682 683 if (lt == rt) 684 return lt; 685 686 if (lt == LCOMPLEX || rt == LCOMPLEX) 687 return LCOMPLEX; 688 if (lt == DCOMPLEX || rt == DCOMPLEX) 689 return DCOMPLEX; 690 if (lt == FCOMPLEX || rt == FCOMPLEX) 691 return FCOMPLEX; 692 if (lt == LDOUBLE || rt == LDOUBLE) 693 return LDOUBLE; 694 if (lt == DOUBLE || rt == DOUBLE) 695 return DOUBLE; 696 if (lt == FLOAT || rt == FLOAT) 697 return FLOAT; 698 699 /* 700 * If type A has more bits than type B, it should be able to hold all 701 * possible values of type B. 702 */ 703 if (size_in_bits(lt) > size_in_bits(rt)) 704 return lt; 705 if (size_in_bits(lt) < size_in_bits(rt)) 706 return rt; 707 708 size_t i; 709 for (i = 3; arith_rank[i] != INT; i++) 710 if (arith_rank[i] == lt || arith_rank[i] == rt) 711 break; 712 if ((is_uinteger(lt) || is_uinteger(rt)) && 713 !is_uinteger(arith_rank[i])) 714 i--; 715 return arith_rank[i]; 716 } 717 718 static tnode_t * 719 apply_usual_arithmetic_conversions(op_t op, tnode_t *tn, tspec_t t) 720 { 721 type_t *ntp = expr_dup_type(tn->tn_type); 722 ntp->t_tspec = t; 723 if (tn->tn_op != CON) { 724 /* usual arithmetic conversion for '%s' from '%s' to '%s' */ 725 query_message(4, op_name(op), 726 type_name(tn->tn_type), type_name(ntp)); 727 } 728 return convert(op, 0, ntp, tn); 729 } 730 731 /* 732 * Apply the "usual arithmetic conversions" (C99 6.3.1.8), which gives both 733 * operands the same type. 734 */ 735 static void 736 balance(op_t op, tnode_t **lnp, tnode_t **rnp) 737 { 738 739 tspec_t lt = (*lnp)->tn_type->t_tspec; 740 tspec_t rt = (*rnp)->tn_type->t_tspec; 741 if (!is_arithmetic(lt) || !is_arithmetic(rt)) 742 return; 743 744 tspec_t t = allow_c90 745 ? usual_arithmetic_conversion_c90(lt, rt) 746 : usual_arithmetic_conversion_trad(lt, rt); 747 748 if (t != lt) 749 *lnp = apply_usual_arithmetic_conversions(op, *lnp, t); 750 if (t != rt) 751 *rnp = apply_usual_arithmetic_conversions(op, *rnp, t); 752 } 753 754 /* 755 * Create a tree node for the unary & operator 756 */ 757 static tnode_t * 758 build_address(bool sys, tnode_t *tn, bool noign) 759 { 760 tspec_t t; 761 762 if (!noign && ((t = tn->tn_type->t_tspec) == ARRAY || t == FUNC)) { 763 if (!allow_c90) 764 /* '&' before array or function: ignored */ 765 warning(127); 766 return tn; 767 } 768 769 /* eliminate &* */ 770 if (tn->tn_op == INDIR && 771 tn->tn_left->tn_type->t_tspec == PTR && 772 tn->tn_left->tn_type->t_subt == tn->tn_type) { 773 return tn->tn_left; 774 } 775 776 return build_op(ADDR, sys, expr_derive_type(tn->tn_type, PTR), 777 tn, NULL); 778 } 779 780 /* 781 * XXX 782 * Note: There appear to be a number of bugs in detecting overflow in 783 * this function. An audit and a set of proper regression tests are needed. 784 * --Perry Metzger, Nov. 16, 2001 785 */ 786 /* 787 * Do only as much as necessary to compute constant expressions. 788 * Called only if the operator allows folding and all operands are constants. 789 */ 790 static tnode_t * 791 fold(tnode_t *tn) 792 { 793 794 val_t *v = xcalloc(1, sizeof(*v)); 795 v->v_tspec = tn->tn_type->t_tspec; 796 797 tspec_t t = tn->tn_left->tn_type->t_tspec; 798 bool utyp = !is_integer(t) || is_uinteger(t); 799 int64_t sl = tn->tn_left->tn_val.u.integer, sr = 0; 800 uint64_t ul = sl, ur = 0; 801 if (is_binary(tn)) 802 ur = sr = tn->tn_right->tn_val.u.integer; 803 804 int64_t mask = (int64_t)value_bits(size_in_bits(t)); 805 bool ovfl = false; 806 807 int64_t si; 808 switch (tn->tn_op) { 809 case UPLUS: 810 si = sl; 811 break; 812 case UMINUS: 813 si = sl == INT64_MIN ? sl : -sl; 814 if (sl != 0 && msb(si, t) == msb(sl, t)) 815 ovfl = true; 816 break; 817 case COMPL: 818 si = ~sl; 819 break; 820 case MULT: 821 if (utyp) { 822 si = (int64_t)(ul * ur); 823 if (si != (si & mask)) 824 ovfl = true; 825 else if ((ul != 0) && ((si / ul) != ur)) 826 ovfl = true; 827 } else { 828 si = sl * sr; 829 if (msb(si, t) != (msb(sl, t) ^ msb(sr, t))) 830 ovfl = true; 831 } 832 break; 833 case DIV: 834 if (sr == 0) { 835 /* division by 0 */ 836 error(139); 837 si = utyp ? -1 : INT64_MAX; 838 } else { 839 si = utyp ? (int64_t)(ul / ur) : sl / sr; 840 } 841 break; 842 case MOD: 843 if (sr == 0) { 844 /* modulus by 0 */ 845 error(140); 846 si = 0; 847 } else { 848 si = utyp ? (int64_t)(ul % ur) : sl % sr; 849 } 850 break; 851 case PLUS: 852 si = utyp ? (int64_t)(ul + ur) : sl + sr; 853 if (msb(sl, t) && msb(sr, t) && !msb(si, t)) 854 ovfl = true; 855 if (!utyp && !msb(sl, t) && !msb(sr, t) && msb(si, t)) 856 ovfl = true; 857 break; 858 case MINUS: 859 si = utyp ? (int64_t)(ul - ur) : sl - sr; 860 if (!utyp && msb(sl, t) && !msb(sr, t) && !msb(si, t)) 861 ovfl = true; 862 if (!msb(sl, t) && msb(sr, t) && msb(si, t)) 863 ovfl = true; 864 break; 865 case SHL: 866 /* TODO: warn about out-of-bounds 'sr'. */ 867 /* TODO: warn about overflow in signed '<<'. */ 868 si = utyp ? (int64_t)(ul << (sr & 63)) : sl << (sr & 63); 869 break; 870 case SHR: 871 /* 872 * The sign must be explicitly extended because 873 * shifts of signed values are implementation dependent. 874 */ 875 /* TODO: warn about out-of-bounds 'sr'. */ 876 si = (int64_t)(ul >> (sr & 63)); 877 si = convert_integer(si, t, size_in_bits(t) - (int)sr); 878 break; 879 case LT: 880 si = (utyp ? ul < ur : sl < sr) ? 1 : 0; 881 break; 882 case LE: 883 si = (utyp ? ul <= ur : sl <= sr) ? 1 : 0; 884 break; 885 case GE: 886 si = (utyp ? ul >= ur : sl >= sr) ? 1 : 0; 887 break; 888 case GT: 889 si = (utyp ? ul > ur : sl > sr) ? 1 : 0; 890 break; 891 case EQ: 892 si = (utyp ? ul == ur : sl == sr) ? 1 : 0; 893 break; 894 case NE: 895 si = (utyp ? ul != ur : sl != sr) ? 1 : 0; 896 break; 897 case BITAND: 898 si = utyp ? (int64_t)(ul & ur) : sl & sr; 899 break; 900 case BITXOR: 901 si = utyp ? (int64_t)(ul ^ ur) : sl ^ sr; 902 break; 903 case BITOR: 904 si = utyp ? (int64_t)(ul | ur) : sl | sr; 905 break; 906 default: 907 lint_assert(/*CONSTCOND*/false); 908 } 909 910 /* XXX: The overflow check does not work for 64-bit integers. */ 911 if (ovfl || 912 ((uint64_t)(si | mask) != ~(uint64_t)0 && (si & ~mask) != 0)) { 913 if (hflag) 914 /* operator '%s' produces integer overflow */ 915 warning(141, op_name(tn->tn_op)); 916 } 917 918 v->u.integer = convert_integer(si, t, 0); 919 920 tnode_t *cn = build_constant(tn->tn_type, v); 921 if (tn->tn_left->tn_system_dependent) 922 cn->tn_system_dependent = true; 923 if (is_binary(tn) && tn->tn_right->tn_system_dependent) 924 cn->tn_system_dependent = true; 925 926 return cn; 927 } 928 929 /* 930 * Create a new node for one of the operators POINT and ARROW. 931 */ 932 static tnode_t * 933 build_struct_access(op_t op, bool sys, tnode_t *ln, tnode_t *rn) 934 { 935 936 lint_assert(rn->tn_op == NAME); 937 lint_assert(is_member(rn->tn_sym)); 938 939 bool lvalue = op == ARROW || ln->tn_lvalue; 940 941 if (op == POINT) { 942 ln = build_address(sys, ln, true); 943 } else if (ln->tn_type->t_tspec != PTR) { 944 lint_assert(!allow_c90); 945 lint_assert(is_integer(ln->tn_type->t_tspec)); 946 ln = convert(NOOP, 0, expr_derive_type(gettyp(VOID), PTR), ln); 947 } 948 949 tnode_t *ctn = build_integer_constant(PTRDIFF_TSPEC, 950 rn->tn_sym->u.s_member.sm_offset_in_bits / CHAR_SIZE); 951 952 type_t *ptr_tp = expr_derive_type(rn->tn_type, PTR); 953 tnode_t *ntn = build_op(PLUS, sys, ptr_tp, ln, ctn); 954 if (ln->tn_op == CON) 955 ntn = fold(ntn); 956 957 op_t nop = rn->tn_type->t_bitfield ? FSEL : INDIR; 958 ntn = build_op(nop, sys, ntn->tn_type->t_subt, ntn, NULL); 959 if (!lvalue) 960 ntn->tn_lvalue = false; 961 962 return ntn; 963 } 964 965 /* 966 * Get the size in bytes of type tp->t_subt, as a constant expression of type 967 * ptrdiff_t as seen from the target platform. 968 */ 969 static tnode_t * 970 subt_size_in_bytes(type_t *tp) 971 { 972 973 lint_assert(tp->t_tspec == PTR); 974 tp = tp->t_subt; 975 976 int elem = 1; 977 while (tp->t_tspec == ARRAY) { 978 elem *= tp->t_dim; 979 tp = tp->t_subt; 980 } 981 982 int elsz_in_bits = 0; 983 switch (tp->t_tspec) { 984 case FUNC: 985 /* pointer to function is not allowed here */ 986 error(110); 987 break; 988 case VOID: 989 /* cannot do pointer arithmetic on operand of unknown size */ 990 gnuism(136); 991 break; 992 case STRUCT: 993 case UNION: 994 if ((elsz_in_bits = (int)tp->t_sou->sou_size_in_bits) == 0) 995 /* cannot do pointer arithmetic on operand of ... */ 996 error(136); 997 break; 998 case ENUM: 999 if (is_incomplete(tp)) { 1000 /* cannot do pointer arithmetic on operand of ... */ 1001 warning(136); 1002 } 1003 /* FALLTHROUGH */ 1004 default: 1005 if ((elsz_in_bits = size_in_bits(tp->t_tspec)) == 0) { 1006 /* cannot do pointer arithmetic on operand of ... */ 1007 error(136); 1008 } else { 1009 lint_assert(elsz_in_bits != -1); 1010 } 1011 break; 1012 } 1013 1014 if (elem == 0 && elsz_in_bits != 0) { 1015 /* cannot do pointer arithmetic on operand of unknown size */ 1016 error(136); 1017 } 1018 1019 if (elsz_in_bits == 0) 1020 elsz_in_bits = CHAR_SIZE; 1021 1022 return build_integer_constant(PTRDIFF_TSPEC, 1023 (int64_t)(elem * elsz_in_bits / CHAR_SIZE)); 1024 } 1025 1026 /* 1027 * Create a node for INCAFT, INCBEF, DECAFT and DECBEF. 1028 */ 1029 static tnode_t * 1030 build_prepost_incdec(op_t op, bool sys, tnode_t *ln) 1031 { 1032 1033 lint_assert(ln != NULL); 1034 tnode_t *cn = ln->tn_type->t_tspec == PTR 1035 ? subt_size_in_bytes(ln->tn_type) 1036 : build_integer_constant(INT, 1); 1037 return build_op(op, sys, ln->tn_type, ln, cn); 1038 } 1039 1040 static void 1041 check_enum_array_index(const tnode_t *ln, const tnode_t *rn) 1042 { 1043 1044 if (ln->tn_op != ADDR || ln->tn_left->tn_op != NAME) 1045 return; 1046 1047 const type_t *ltp = ln->tn_left->tn_type; 1048 if (ltp->t_tspec != ARRAY || ltp->t_incomplete_array) 1049 return; 1050 1051 if (rn->tn_op != CVT || !rn->tn_type->t_is_enum) 1052 return; 1053 if (rn->tn_left->tn_op != LOAD) 1054 return; 1055 1056 const type_t *rtp = rn->tn_left->tn_type; 1057 const sym_t *ec = rtp->t_enum->en_first_enumerator; 1058 const sym_t *max_ec = ec; 1059 lint_assert(ec != NULL); 1060 for (ec = ec->s_next; ec != NULL; ec = ec->s_next) 1061 if (ec->u.s_enum_constant > max_ec->u.s_enum_constant) 1062 max_ec = ec; 1063 1064 int64_t max_enum_value = max_ec->u.s_enum_constant; 1065 lint_assert(INT_MIN <= max_enum_value && max_enum_value <= INT_MAX); 1066 1067 int max_array_index = ltp->t_dim - 1; 1068 if (max_enum_value == max_array_index) 1069 return; 1070 1071 /* 1072 * If the name of the largest enum constant contains 'MAX' or 'NUM', 1073 * that constant is typically not part of the allowed enum values but 1074 * a marker for the number of actual enum values. 1075 */ 1076 if (max_enum_value == max_array_index + 1 && 1077 (strstr(max_ec->s_name, "MAX") != NULL || 1078 strstr(max_ec->s_name, "max") != NULL || 1079 strstr(max_ec->s_name, "NUM") != NULL || 1080 strstr(max_ec->s_name, "num") != NULL)) 1081 return; 1082 1083 /* maximum value %d of '%s' does not match maximum array index %d */ 1084 warning(348, (int)max_enum_value, type_name(rtp), max_array_index); 1085 print_previous_declaration(max_ec); 1086 } 1087 1088 /* 1089 * Create a node for operators PLUS and MINUS. 1090 */ 1091 static tnode_t * 1092 build_plus_minus(op_t op, bool sys, tnode_t *ln, tnode_t *rn) 1093 { 1094 1095 /* If pointer and integer, move the pointer to the left. */ 1096 if (rn->tn_type->t_tspec == PTR && is_integer(ln->tn_type->t_tspec)) { 1097 tnode_t *tmp = ln; 1098 ln = rn; 1099 rn = tmp; 1100 /* pointer addition has integer on the left-hand side */ 1101 query_message(5); 1102 } 1103 1104 /* pointer +- integer */ 1105 if (ln->tn_type->t_tspec == PTR && rn->tn_type->t_tspec != PTR) { 1106 lint_assert(is_integer(rn->tn_type->t_tspec)); 1107 1108 check_ctype_macro_invocation(ln, rn); 1109 check_enum_array_index(ln, rn); 1110 1111 tnode_t *elsz = subt_size_in_bytes(ln->tn_type); 1112 if (rn->tn_type->t_tspec != elsz->tn_type->t_tspec) 1113 rn = convert(NOOP, 0, elsz->tn_type, rn); 1114 1115 tnode_t *prod = build_op(MULT, sys, rn->tn_type, rn, elsz); 1116 if (rn->tn_op == CON) 1117 prod = fold(prod); 1118 1119 return build_op(op, sys, ln->tn_type, ln, prod); 1120 } 1121 1122 /* pointer - pointer */ 1123 if (rn->tn_type->t_tspec == PTR) { 1124 lint_assert(ln->tn_type->t_tspec == PTR); 1125 lint_assert(op == MINUS); 1126 1127 type_t *ptrdiff = gettyp(PTRDIFF_TSPEC); 1128 tnode_t *raw_diff = build_op(op, sys, ptrdiff, ln, rn); 1129 if (ln->tn_op == CON && rn->tn_op == CON) 1130 raw_diff = fold(raw_diff); 1131 1132 tnode_t *elsz = subt_size_in_bytes(ln->tn_type); 1133 balance(NOOP, &raw_diff, &elsz); 1134 1135 return build_op(DIV, sys, ptrdiff, raw_diff, elsz); 1136 } 1137 1138 return build_op(op, sys, ln->tn_type, ln, rn); 1139 } 1140 1141 /* 1142 * Create a node for operators SHL and SHR. 1143 */ 1144 static tnode_t * 1145 build_bit_shift(op_t op, bool sys, tnode_t *ln, tnode_t *rn) 1146 { 1147 1148 if (!allow_c90 && rn->tn_type->t_tspec != INT) 1149 // XXX: C1978 7.5 says: "Both [operators] perform the usual 1150 // arithmetic conversions on their operands." 1151 // TODO: Add a test to exercise this part of the code. 1152 rn = convert(NOOP, 0, gettyp(INT), rn); 1153 return build_op(op, sys, ln->tn_type, ln, rn); 1154 } 1155 1156 static bool 1157 is_null_pointer(const tnode_t *tn) 1158 { 1159 tspec_t t = tn->tn_type->t_tspec; 1160 1161 // TODO: Investigate how other pointers are stored, in particular, 1162 // whether a pointer constant can have a non-zero value. 1163 // If not, simplify the code below. 1164 return ((t == PTR && tn->tn_type->t_subt->t_tspec == VOID) || 1165 is_integer(t)) 1166 && (tn->tn_op == CON && tn->tn_val.u.integer == 0); 1167 } 1168 1169 /* Return a type based on tp1, with added qualifiers from tp2. */ 1170 static type_t * 1171 merge_qualifiers(type_t *tp1, const type_t *tp2) 1172 { 1173 1174 lint_assert(tp1->t_tspec == PTR); 1175 lint_assert(tp2->t_tspec == PTR); 1176 1177 bool c1 = tp1->t_subt->t_const; 1178 bool c2 = tp2->t_subt->t_const; 1179 bool v1 = tp1->t_subt->t_volatile; 1180 bool v2 = tp2->t_subt->t_volatile; 1181 1182 if (c1 == (c1 | c2) && v1 == (v1 | v2)) 1183 return tp1; 1184 1185 type_t *nstp = expr_dup_type(tp1->t_subt); 1186 nstp->t_const |= c2; 1187 nstp->t_volatile |= v2; 1188 1189 type_t *ntp = expr_dup_type(tp1); 1190 ntp->t_subt = nstp; 1191 return ntp; 1192 } 1193 1194 /* See C99 6.5.15 "Conditional operator". */ 1195 static tnode_t * 1196 build_colon(bool sys, tnode_t *ln, tnode_t *rn) 1197 { 1198 1199 tspec_t lt = ln->tn_type->t_tspec; 1200 tspec_t rt = rn->tn_type->t_tspec; 1201 1202 type_t *tp; 1203 if (is_arithmetic(lt) && is_arithmetic(rt)) { 1204 /* The operands were already balanced in build_binary. */ 1205 tp = ln->tn_type; 1206 } else if (lt == BOOL && rt == BOOL) { 1207 tp = ln->tn_type; 1208 } else if (lt == VOID || rt == VOID) { 1209 tp = gettyp(VOID); 1210 } else if (is_struct_or_union(lt)) { 1211 /* Both types must be identical. */ 1212 lint_assert(is_struct_or_union(rt)); 1213 lint_assert(ln->tn_type->t_sou == rn->tn_type->t_sou); 1214 if (is_incomplete(ln->tn_type)) { 1215 /* unknown operand size, op '%s' */ 1216 error(138, op_name(COLON)); 1217 return NULL; 1218 } 1219 tp = ln->tn_type; 1220 } else if (lt == PTR && is_integer(rt)) { 1221 if (rt != PTRDIFF_TSPEC) 1222 rn = convert(NOOP, 0, gettyp(PTRDIFF_TSPEC), rn); 1223 tp = ln->tn_type; 1224 } else if (rt == PTR && is_integer(lt)) { 1225 if (lt != PTRDIFF_TSPEC) 1226 ln = convert(NOOP, 0, gettyp(PTRDIFF_TSPEC), ln); 1227 tp = rn->tn_type; 1228 } else if (lt == PTR && is_null_pointer(rn)) { 1229 tp = merge_qualifiers(ln->tn_type, rn->tn_type); 1230 } else if (rt == PTR && is_null_pointer(ln)) { 1231 tp = merge_qualifiers(rn->tn_type, ln->tn_type); 1232 } else if (lt == PTR && ln->tn_type->t_subt->t_tspec == VOID) { 1233 tp = merge_qualifiers(ln->tn_type, rn->tn_type); 1234 } else if (rt == PTR && rn->tn_type->t_subt->t_tspec == VOID) { 1235 tp = merge_qualifiers(rn->tn_type, ln->tn_type); 1236 } else { 1237 /* 1238 * XXX For now we simply take the left type. This is 1239 * probably wrong, if one type contains a function prototype 1240 * and the other one, at the same place, only an old-style 1241 * declaration. 1242 */ 1243 tp = merge_qualifiers(ln->tn_type, rn->tn_type); 1244 } 1245 1246 return build_op(COLON, sys, tp, ln, rn); 1247 } 1248 1249 /* TODO: check for varargs */ 1250 static bool 1251 is_cast_redundant(const tnode_t *tn) 1252 { 1253 const type_t *ntp = tn->tn_type, *otp = tn->tn_left->tn_type; 1254 tspec_t nt = ntp->t_tspec, ot = otp->t_tspec; 1255 1256 if (nt == BOOL || ot == BOOL) 1257 return nt == BOOL && ot == BOOL; 1258 1259 if (is_integer(nt) && is_integer(ot)) { 1260 unsigned int nw = width_in_bits(ntp), ow = width_in_bits(otp); 1261 if (is_uinteger(nt) == is_uinteger(ot)) 1262 return nw >= ow; 1263 return is_uinteger(ot) && nw > ow; 1264 } 1265 1266 if (is_complex(nt) || is_complex(ot)) 1267 return is_complex(nt) && is_complex(ot) && 1268 size_in_bits(nt) >= size_in_bits(ot); 1269 1270 if (is_floating(nt) && is_floating(ot)) 1271 return size_in_bits(nt) >= size_in_bits(ot); 1272 1273 if (nt == PTR && ot == PTR) { 1274 if (!ntp->t_subt->t_const && otp->t_subt->t_const) 1275 return false; 1276 if (!ntp->t_subt->t_volatile && otp->t_subt->t_volatile) 1277 return false; 1278 1279 if (ntp->t_subt->t_tspec == VOID || 1280 otp->t_subt->t_tspec == VOID || 1281 types_compatible(ntp->t_subt, otp->t_subt, 1282 false, false, NULL)) 1283 return true; 1284 } 1285 1286 return false; 1287 } 1288 1289 static bool 1290 is_assignment(op_t op) 1291 { 1292 1293 return op == ASSIGN || 1294 op == MULASS || 1295 op == DIVASS || 1296 op == MODASS || 1297 op == ADDASS || 1298 op == SUBASS || 1299 op == SHLASS || 1300 op == SHRASS || 1301 op == ANDASS || 1302 op == XORASS || 1303 op == ORASS || 1304 op == RETURN || 1305 op == INIT; 1306 } 1307 1308 /* Create a node for an assignment operator (both '=' and 'op='). */ 1309 static tnode_t * 1310 build_assignment(op_t op, bool sys, tnode_t *ln, tnode_t *rn) 1311 { 1312 1313 tspec_t lt = ln->tn_type->t_tspec; 1314 tspec_t rt = rn->tn_type->t_tspec; 1315 1316 if (any_query_enabled && is_assignment(rn->tn_op)) { 1317 /* chained assignment with '%s' and '%s' */ 1318 query_message(10, op_name(op), op_name(rn->tn_op)); 1319 } 1320 1321 if ((op == ADDASS || op == SUBASS) && lt == PTR) { 1322 lint_assert(is_integer(rt)); 1323 tnode_t *ctn = subt_size_in_bytes(ln->tn_type); 1324 if (rn->tn_type->t_tspec != ctn->tn_type->t_tspec) 1325 rn = convert(NOOP, 0, ctn->tn_type, rn); 1326 rn = build_op(MULT, sys, rn->tn_type, rn, ctn); 1327 if (rn->tn_left->tn_op == CON) 1328 rn = fold(rn); 1329 } 1330 1331 if ((op == ASSIGN || op == RETURN || op == INIT) && 1332 (lt == STRUCT || rt == STRUCT)) { 1333 lint_assert(lt == rt); 1334 lint_assert(ln->tn_type->t_sou == rn->tn_type->t_sou); 1335 if (is_incomplete(ln->tn_type)) { 1336 if (op == RETURN) { 1337 /* cannot return incomplete type */ 1338 error(212); 1339 } else { 1340 /* unknown operand size, op '%s' */ 1341 error(138, op_name(op)); 1342 } 1343 return NULL; 1344 } 1345 } 1346 1347 if (op == SHLASS && hflag && allow_trad && allow_c90 1348 && portable_rank_cmp(lt, rt) < 0) 1349 /* semantics of '%s' change in ANSI C; ... */ 1350 warning(118, "<<="); 1351 1352 if (op != SHLASS && op != SHRASS 1353 && (op == ASSIGN || lt != PTR) 1354 && (lt != rt || (ln->tn_type->t_bitfield && rn->tn_op == CON))) { 1355 rn = convert(op, 0, ln->tn_type, rn); 1356 rt = lt; 1357 } 1358 1359 if (any_query_enabled && rn->tn_op == CVT && rn->tn_cast && 1360 types_compatible(ln->tn_type, rn->tn_type, false, false, NULL) && 1361 is_cast_redundant(rn)) { 1362 /* redundant cast from '%s' to '%s' before assignment */ 1363 query_message(7, 1364 type_name(rn->tn_left->tn_type), type_name(rn->tn_type)); 1365 } 1366 1367 return build_op(op, sys, ln->tn_type, ln, rn); 1368 } 1369 1370 /* 1371 * Create a node for REAL, IMAG 1372 */ 1373 static tnode_t * 1374 build_real_imag(op_t op, bool sys, tnode_t *ln) 1375 { 1376 1377 lint_assert(ln != NULL); 1378 if (ln->tn_op == NAME) { 1379 /* 1380 * This may be too much, but it avoids wrong warnings. 1381 * See d_c99_complex_split.c. 1382 */ 1383 mark_as_used(ln->tn_sym, false, false); 1384 mark_as_set(ln->tn_sym); 1385 } 1386 1387 tspec_t t; 1388 switch (ln->tn_type->t_tspec) { 1389 case LCOMPLEX: 1390 t = LDOUBLE; 1391 break; 1392 case DCOMPLEX: 1393 t = DOUBLE; 1394 break; 1395 case FCOMPLEX: 1396 t = FLOAT; 1397 break; 1398 default: 1399 /* '__%s__' is illegal for type '%s' */ 1400 error(276, op == REAL ? "real" : "imag", 1401 type_name(ln->tn_type)); 1402 return NULL; 1403 } 1404 1405 tnode_t *ntn = build_op(op, sys, gettyp(t), ln, NULL); 1406 ntn->tn_lvalue = true; 1407 return ntn; 1408 } 1409 1410 static bool 1411 is_confusing_precedence(op_t op, op_t lop, bool lparen, op_t rop, bool rparen) 1412 { 1413 1414 if (op == SHL || op == SHR) { 1415 if (!lparen && (lop == PLUS || lop == MINUS)) 1416 return true; 1417 if (!rparen && (rop == PLUS || rop == MINUS)) 1418 return true; 1419 return false; 1420 } 1421 1422 if (op == LOGOR) { 1423 if (!lparen && lop == LOGAND) 1424 return true; 1425 if (!rparen && rop == LOGAND) 1426 return true; 1427 return false; 1428 } 1429 1430 lint_assert(op == BITAND || op == BITXOR || op == BITOR); 1431 if (!lparen && lop != op) { 1432 if (lop == PLUS || lop == MINUS) 1433 return true; 1434 if (lop == BITAND || lop == BITXOR) 1435 return true; 1436 } 1437 if (!rparen && rop != op) { 1438 if (rop == PLUS || rop == MINUS) 1439 return true; 1440 if (rop == BITAND || rop == BITXOR) 1441 return true; 1442 } 1443 return false; 1444 } 1445 1446 /* 1447 * Print a warning if the given node has operands which should be 1448 * parenthesized. 1449 * 1450 * XXX Does not work if an operand is a constant expression. Constant 1451 * expressions are already folded. 1452 */ 1453 static void 1454 check_precedence_confusion(tnode_t *tn) 1455 { 1456 tnode_t *ln, *rn; 1457 1458 if (!hflag) 1459 return; 1460 1461 debug_node(tn); 1462 1463 lint_assert(is_binary(tn)); 1464 for (ln = tn->tn_left; ln->tn_op == CVT; ln = ln->tn_left) 1465 continue; 1466 for (rn = tn->tn_right; rn->tn_op == CVT; rn = rn->tn_left) 1467 continue; 1468 1469 if (is_confusing_precedence(tn->tn_op, 1470 ln->tn_op, ln->tn_parenthesized, 1471 rn->tn_op, rn->tn_parenthesized)) { 1472 /* precedence confusion possible: parenthesize! */ 1473 warning(169); 1474 } 1475 } 1476 1477 /* 1478 * Fold constant nodes, as much as is needed for comparing the value with 0. 1479 */ 1480 static tnode_t * 1481 fold_bool(tnode_t *tn) 1482 { 1483 1484 val_t *v = xcalloc(1, sizeof(*v)); 1485 v->v_tspec = tn->tn_type->t_tspec; 1486 lint_assert(v->v_tspec == INT || (Tflag && v->v_tspec == BOOL)); 1487 1488 bool l = constant_is_nonzero(tn->tn_left); 1489 bool r = is_binary(tn) && constant_is_nonzero(tn->tn_right); 1490 1491 switch (tn->tn_op) { 1492 case NOT: 1493 if (hflag && !suppress_constcond) 1494 /* constant argument to '!' */ 1495 warning(239); 1496 v->u.integer = !l ? 1 : 0; 1497 break; 1498 case LOGAND: 1499 v->u.integer = l && r ? 1 : 0; 1500 break; 1501 case LOGOR: 1502 v->u.integer = l || r ? 1 : 0; 1503 break; 1504 default: 1505 lint_assert(/*CONSTCOND*/false); 1506 } 1507 1508 return build_constant(tn->tn_type, v); 1509 } 1510 1511 static long double 1512 floating_error_value(tspec_t t, long double lv) 1513 { 1514 if (t == FLOAT) 1515 return lv < 0 ? -FLT_MAX : FLT_MAX; 1516 if (t == DOUBLE) 1517 return lv < 0 ? -DBL_MAX : DBL_MAX; 1518 /* 1519 * When NetBSD is cross-built in MKLINT=yes mode on x86_64 for 1520 * sparc64, tools/lint checks this code while building usr.bin/xlint. 1521 * In that situation, lint uses the preprocessor for sparc64, in which 1522 * the type 'long double' is IEEE-754-binary128, affecting the macro 1523 * LDBL_MAX below. The type 'long double', as well as the strtold 1524 * implementation, comes from the host platform x86_64 though, where 1525 * 'long double' consumes 128 bits as well but only uses 80 of them. 1526 * The exponent range of the two 'long double' types is the same, but 1527 * the maximum finite value differs due to the extended precision on 1528 * sparc64. 1529 * 1530 * To properly handle the data types of the target platform, lint 1531 * would have to implement the floating-point types in a 1532 * platform-independent way, which is not worth the effort, given how 1533 * few programs practically use 'long double'. 1534 */ 1535 /* LINTED 248: floating-point constant out of range */ 1536 long double max = LDBL_MAX; 1537 return lv < 0 ? -max : max; 1538 } 1539 1540 static bool 1541 is_floating_overflow(tspec_t t, long double val) 1542 { 1543 if (fpe != 0 || isfinite(val) == 0) 1544 return true; 1545 if (t == FLOAT && (val > FLT_MAX || val < -FLT_MAX)) 1546 return true; 1547 if (t == DOUBLE && (val > DBL_MAX || val < -DBL_MAX)) 1548 return true; 1549 return false; 1550 } 1551 1552 /* 1553 * Fold constant nodes having operands with floating point type. 1554 */ 1555 static tnode_t * 1556 fold_float(tnode_t *tn) 1557 { 1558 1559 fpe = 0; 1560 1561 tspec_t t = tn->tn_type->t_tspec; 1562 1563 val_t *v = xcalloc(1, sizeof(*v)); 1564 v->v_tspec = t; 1565 1566 lint_assert(is_floating(t)); 1567 lint_assert(t == tn->tn_left->tn_type->t_tspec); 1568 lint_assert(!is_binary(tn) || t == tn->tn_right->tn_type->t_tspec); 1569 1570 long double lv = tn->tn_left->tn_val.u.floating; 1571 long double rv = is_binary(tn) ? tn->tn_right->tn_val.u.floating : 0.0; 1572 1573 switch (tn->tn_op) { 1574 case UPLUS: 1575 v->u.floating = lv; 1576 break; 1577 case UMINUS: 1578 v->u.floating = -lv; 1579 break; 1580 case MULT: 1581 v->u.floating = lv * rv; 1582 break; 1583 case DIV: 1584 if (rv == 0.0) { 1585 /* division by 0 */ 1586 error(139); 1587 v->u.floating = floating_error_value(t, lv); 1588 } else { 1589 v->u.floating = lv / rv; 1590 } 1591 break; 1592 case PLUS: 1593 v->u.floating = lv + rv; 1594 break; 1595 case MINUS: 1596 v->u.floating = lv - rv; 1597 break; 1598 case LT: 1599 v->u.integer = lv < rv ? 1 : 0; 1600 break; 1601 case LE: 1602 v->u.integer = lv <= rv ? 1 : 0; 1603 break; 1604 case GE: 1605 v->u.integer = lv >= rv ? 1 : 0; 1606 break; 1607 case GT: 1608 v->u.integer = lv > rv ? 1 : 0; 1609 break; 1610 case EQ: 1611 v->u.integer = lv == rv ? 1 : 0; 1612 break; 1613 case NE: 1614 v->u.integer = lv != rv ? 1 : 0; 1615 break; 1616 default: 1617 lint_assert(/*CONSTCOND*/false); 1618 } 1619 1620 // XXX: Must not access u.floating after setting u.integer. 1621 lint_assert(fpe != 0 || isnan(v->u.floating) == 0); 1622 if (is_complex(v->v_tspec)) { 1623 /* 1624 * Don't warn, as lint doesn't model the imaginary part of 1625 * complex numbers. 1626 */ 1627 fpe = 0; 1628 } else if (is_floating_overflow(t, v->u.floating)) { 1629 /* operator '%s' produces floating point overflow */ 1630 warning(142, op_name(tn->tn_op)); 1631 v->u.floating = floating_error_value(t, v->u.floating); 1632 fpe = 0; 1633 } 1634 1635 return build_constant(tn->tn_type, v); 1636 } 1637 1638 /* 1639 * Create a tree node for a binary operator and its two operands. Also called 1640 * for unary operators; in that case rn is NULL. 1641 * 1642 * Function calls, sizeof and casts are handled elsewhere. 1643 */ 1644 tnode_t * 1645 build_binary(tnode_t *ln, op_t op, bool sys, tnode_t *rn) 1646 { 1647 const mod_t *mp = &modtab[op]; 1648 1649 /* If there was an error in one of the operands, return. */ 1650 if (ln == NULL || (mp->m_binary && rn == NULL)) 1651 return NULL; 1652 1653 /* 1654 * Apply class conversions to the left operand, but only if its 1655 * value is needed or compared with zero. 1656 */ 1657 if (mp->m_value_context || mp->m_compares_with_zero) 1658 ln = cconv(ln); 1659 /* 1660 * The right operand is almost always in a test or value context, 1661 * except if it is a struct or union member. 1662 */ 1663 if (mp->m_binary && op != ARROW && op != POINT) 1664 rn = cconv(rn); 1665 1666 /* 1667 * Print some warnings for comparisons of unsigned values with 1668 * constants lower than or equal to null. This must be done 1669 * before promote() because otherwise unsigned char and unsigned 1670 * short would be promoted to int. Types are also tested to be 1671 * CHAR, which would also become int. 1672 */ 1673 if (mp->m_comparison) 1674 check_integer_comparison(op, ln, rn); 1675 1676 if (mp->m_value_context || mp->m_compares_with_zero) 1677 ln = promote(op, false, ln); 1678 if (mp->m_binary && op != ARROW && op != POINT && 1679 op != ASSIGN && op != RETURN && op != INIT) { 1680 rn = promote(op, false, rn); 1681 } 1682 1683 /* 1684 * If the result of the operation is different for signed or 1685 * unsigned operands and one of the operands is signed only in 1686 * ANSI C, print a warning. 1687 */ 1688 if (mp->m_warn_if_left_unsigned_in_c90 && 1689 ln->tn_op == CON && ln->tn_val.v_unsigned_since_c90) { 1690 /* ANSI C treats constant as unsigned, op '%s' */ 1691 warning(218, op_name(op)); 1692 ln->tn_val.v_unsigned_since_c90 = false; 1693 } 1694 if (mp->m_warn_if_right_unsigned_in_c90 && 1695 rn->tn_op == CON && rn->tn_val.v_unsigned_since_c90) { 1696 /* ANSI C treats constant as unsigned, op '%s' */ 1697 warning(218, op_name(op)); 1698 rn->tn_val.v_unsigned_since_c90 = false; 1699 } 1700 1701 /* Make sure both operands are of the same type */ 1702 if (mp->m_balance_operands || (!allow_c90 && (op == SHL || op == SHR))) 1703 balance(op, &ln, &rn); 1704 1705 /* 1706 * Check types for compatibility with the operation and mutual 1707 * compatibility. Return if there are serious problems. 1708 */ 1709 if (!typeok(op, 0, ln, rn)) 1710 return NULL; 1711 1712 /* And now create the node. */ 1713 tnode_t *ntn; 1714 switch (op) { 1715 case POINT: 1716 case ARROW: 1717 ntn = build_struct_access(op, sys, ln, rn); 1718 break; 1719 case INCAFT: 1720 case DECAFT: 1721 case INCBEF: 1722 case DECBEF: 1723 ntn = build_prepost_incdec(op, sys, ln); 1724 break; 1725 case ADDR: 1726 ntn = build_address(sys, ln, false); 1727 break; 1728 case INDIR: 1729 ntn = build_op(INDIR, sys, ln->tn_type->t_subt, ln, NULL); 1730 break; 1731 case PLUS: 1732 case MINUS: 1733 ntn = build_plus_minus(op, sys, ln, rn); 1734 break; 1735 case SHL: 1736 case SHR: 1737 ntn = build_bit_shift(op, sys, ln, rn); 1738 break; 1739 case COLON: 1740 ntn = build_colon(sys, ln, rn); 1741 break; 1742 case ASSIGN: 1743 case MULASS: 1744 case DIVASS: 1745 case MODASS: 1746 case ADDASS: 1747 case SUBASS: 1748 case SHLASS: 1749 case SHRASS: 1750 case ANDASS: 1751 case XORASS: 1752 case ORASS: 1753 case RETURN: 1754 case INIT: 1755 ntn = build_assignment(op, sys, ln, rn); 1756 break; 1757 case COMMA: 1758 if (any_query_enabled) { 1759 /* comma operator with types '%s' and '%s' */ 1760 query_message(12, 1761 type_name(ln->tn_type), type_name(rn->tn_type)); 1762 } 1763 /* FALLTHROUGH */ 1764 case QUEST: 1765 ntn = build_op(op, sys, rn->tn_type, ln, rn); 1766 break; 1767 case REAL: 1768 case IMAG: 1769 ntn = build_real_imag(op, sys, ln); 1770 break; 1771 default: 1772 lint_assert(mp->m_binary == (rn != NULL)); 1773 type_t *rettp = mp->m_returns_bool 1774 ? gettyp(Tflag ? BOOL : INT) : ln->tn_type; 1775 ntn = build_op(op, sys, rettp, ln, rn); 1776 break; 1777 } 1778 1779 /* Return if an error occurred. */ 1780 if (ntn == NULL) 1781 return NULL; 1782 1783 /* Print a warning if precedence confusion is possible */ 1784 if (mp->m_possible_precedence_confusion) 1785 check_precedence_confusion(ntn); 1786 1787 /* 1788 * Print a warning if one of the operands is in a context where 1789 * it is compared with zero and if this operand is a constant. 1790 */ 1791 if (hflag && !suppress_constcond && 1792 mp->m_compares_with_zero && 1793 (ln->tn_op == CON || 1794 ((mp->m_binary && op != QUEST) && rn->tn_op == CON)) && 1795 /* XXX: rn->tn_system_dependent should be checked as well */ 1796 !ln->tn_system_dependent) { 1797 /* constant in conditional context */ 1798 warning(161); 1799 } 1800 1801 /* Fold if the operator requires it */ 1802 if (mp->m_fold_constant_operands) { 1803 if (ln->tn_op == CON && (!mp->m_binary || rn->tn_op == CON)) { 1804 if (mp->m_compares_with_zero) { 1805 ntn = fold_bool(ntn); 1806 } else if (is_floating(ntn->tn_type->t_tspec)) { 1807 ntn = fold_float(ntn); 1808 } else { 1809 ntn = fold(ntn); 1810 } 1811 } else if (op == QUEST && ln->tn_op == CON) { 1812 ntn = ln->tn_val.u.integer != 0 1813 ? rn->tn_left : rn->tn_right; 1814 } 1815 } 1816 1817 return ntn; 1818 } 1819 1820 tnode_t * 1821 build_unary(op_t op, bool sys, tnode_t *tn) 1822 { 1823 return build_binary(tn, op, sys, NULL); 1824 } 1825 1826 static bool 1827 are_members_compatible(const sym_t *a, const sym_t *b) 1828 { 1829 if (a->u.s_member.sm_offset_in_bits != b->u.s_member.sm_offset_in_bits) 1830 return false; 1831 1832 const type_t *atp = a->s_type; 1833 const type_t *btp = b->s_type; 1834 bool w = false; 1835 if (!types_compatible(atp, btp, false, false, &w) && !w) 1836 return false; 1837 if (a->s_bitfield != b->s_bitfield) 1838 return false; 1839 if (a->s_bitfield) { 1840 if (atp->t_bit_field_width != btp->t_bit_field_width) 1841 return false; 1842 if (atp->t_bit_field_offset != btp->t_bit_field_offset) 1843 return false; 1844 } 1845 return true; 1846 } 1847 1848 /* 1849 * Return whether all struct/union members with the same name have the same 1850 * type and offset. 1851 */ 1852 static bool 1853 all_members_compatible(const sym_t *msym) 1854 { 1855 for (const sym_t *csym = msym; 1856 csym != NULL; csym = csym->s_symtab_next) { 1857 if (!is_member(csym)) 1858 continue; 1859 if (strcmp(msym->s_name, csym->s_name) != 0) 1860 continue; 1861 1862 for (const sym_t *sym = csym->s_symtab_next; 1863 sym != NULL; sym = sym->s_symtab_next) { 1864 if (is_member(sym) 1865 && strcmp(csym->s_name, sym->s_name) == 0 1866 && !are_members_compatible(csym, sym)) 1867 return false; 1868 } 1869 } 1870 return true; 1871 } 1872 1873 sym_t * 1874 find_member(const type_t *tp, const char *name) 1875 { 1876 for (sym_t *mem = tp->t_sou->sou_first_member; 1877 mem != NULL; mem = mem->s_next) { 1878 if (strcmp(mem->s_name, name) == 0) 1879 return mem; 1880 } 1881 for (sym_t *mem = tp->t_sou->sou_first_member; 1882 mem != NULL; mem = mem->s_next) { 1883 if (is_struct_or_union(mem->s_type->t_tspec) && 1884 mem->s_name == unnamed) { 1885 sym_t *nested_mem = find_member(mem->s_type, name); 1886 if (nested_mem != NULL) 1887 return nested_mem; 1888 } 1889 } 1890 return NULL; 1891 } 1892 1893 /* 1894 * Returns a symbol which has the same name as the msym argument and is a 1895 * member of the struct or union specified by the tn argument. 1896 */ 1897 static sym_t * 1898 struct_or_union_member(tnode_t *tn, op_t op, sym_t *msym) 1899 { 1900 1901 /* 1902 * Remove the member if it was unknown until now, which means 1903 * that no defined struct or union has a member with the same name. 1904 */ 1905 if (msym->s_scl == NOSCL) { 1906 /* type '%s' does not have member '%s' */ 1907 error(101, type_name(tn->tn_type), msym->s_name); 1908 rmsym(msym); 1909 msym->s_kind = FMEMBER; 1910 msym->s_scl = STRUCT_MEMBER; 1911 1912 struct_or_union *sou = expr_zero_alloc(sizeof(*sou)); 1913 sou->sou_tag = expr_zero_alloc(sizeof(*sou->sou_tag)); 1914 sou->sou_tag->s_name = unnamed; 1915 1916 msym->u.s_member.sm_containing_type = sou; 1917 /* 1918 * The member sm_offset_in_bits is not needed here since this 1919 * symbol can only be used for error reporting. 1920 */ 1921 return msym; 1922 } 1923 1924 /* Determine the tag type of which msym is expected to be a member. */ 1925 const type_t *tp = NULL; 1926 if (op == POINT && is_struct_or_union(tn->tn_type->t_tspec)) 1927 tp = tn->tn_type; 1928 if (op == ARROW && tn->tn_type->t_tspec == PTR 1929 && is_struct_or_union(tn->tn_type->t_subt->t_tspec)) 1930 tp = tn->tn_type->t_subt; 1931 struct_or_union *sou = tp != NULL ? tp->t_sou : NULL; 1932 1933 /* 1934 * If this struct/union has a member with the name of msym, return it. 1935 */ 1936 if (sou != NULL) { 1937 for (sym_t *sym = msym; 1938 sym != NULL; sym = sym->s_symtab_next) { 1939 if (is_member(sym) && 1940 sym->u.s_member.sm_containing_type == sou && 1941 strcmp(sym->s_name, msym->s_name) == 0) 1942 return sym; 1943 } 1944 } 1945 1946 if (tp != NULL) { 1947 sym_t *nested_mem = find_member(tp, msym->s_name); 1948 if (nested_mem != NULL) 1949 return nested_mem; 1950 } 1951 1952 bool eq = all_members_compatible(msym); 1953 1954 /* 1955 * Now handle the case in which the left operand refers really 1956 * to a struct/union, but the right operand is not member of it. 1957 */ 1958 if (sou != NULL) { 1959 if (eq && !allow_c90) { 1960 /* illegal use of member '%s' */ 1961 warning(102, msym->s_name); 1962 } else { 1963 /* illegal use of member '%s' */ 1964 error(102, msym->s_name); 1965 } 1966 return msym; 1967 } 1968 1969 /* 1970 * Now the left operand of ARROW does not point to a struct/union 1971 * or the left operand of POINT is no struct/union. 1972 */ 1973 if (eq) { 1974 if (op == POINT) { 1975 if (!allow_c90) { 1976 /* left operand of '.' must be struct ... */ 1977 warning(103, type_name(tn->tn_type)); 1978 } else { 1979 /* left operand of '.' must be struct ... */ 1980 error(103, type_name(tn->tn_type)); 1981 } 1982 } else { 1983 if (!allow_c90 && tn->tn_type->t_tspec == PTR) { 1984 /* left operand of '->' must be pointer ... */ 1985 warning(104, type_name(tn->tn_type)); 1986 } else { 1987 /* left operand of '->' must be pointer ... */ 1988 error(104, type_name(tn->tn_type)); 1989 } 1990 } 1991 } else { 1992 if (!allow_c90) { 1993 /* non-unique member requires struct/union %s */ 1994 error(105, op == POINT ? "object" : "pointer"); 1995 } else { 1996 /* unacceptable operand of '%s' */ 1997 error(111, op_name(op)); 1998 } 1999 } 2000 2001 return msym; 2002 } 2003 2004 tnode_t * 2005 build_member_access(tnode_t *ln, op_t op, bool sys, sbuf_t *member) 2006 { 2007 sym_t *msym; 2008 2009 if (ln == NULL) 2010 return NULL; 2011 2012 if (op == ARROW) { 2013 /* must do this before struct_or_union_member is called */ 2014 ln = cconv(ln); 2015 } 2016 msym = struct_or_union_member(ln, op, getsym(member)); 2017 return build_binary(ln, op, sys, build_name(msym, false)); 2018 } 2019 2020 /* 2021 * Perform class conversions. 2022 * 2023 * Arrays of type T are converted into pointers to type T. 2024 * Functions are converted to pointers to functions. 2025 * Lvalues are converted to rvalues. 2026 * 2027 * C99 6.3 "Conversions" 2028 * C99 6.3.2 "Other operands" 2029 * C99 6.3.2.1 "Lvalues, arrays, and function designators" 2030 */ 2031 tnode_t * 2032 cconv(tnode_t *tn) 2033 { 2034 /* 2035 * Array-lvalue (array of type T) is converted into rvalue 2036 * (pointer to type T) 2037 */ 2038 if (tn->tn_type->t_tspec == ARRAY) { 2039 if (!tn->tn_lvalue) { 2040 /* XXX print correct operator */ 2041 /* %soperand of '%s' must be lvalue */ 2042 gnuism(114, "", op_name(ADDR)); 2043 } 2044 tn = build_op(ADDR, tn->tn_sys, 2045 expr_derive_type(tn->tn_type->t_subt, PTR), tn, NULL); 2046 } 2047 2048 /* 2049 * Expression of type function (function with return value of type T) 2050 * in rvalue-expression (pointer to function with return value 2051 * of type T) 2052 */ 2053 if (tn->tn_type->t_tspec == FUNC) 2054 tn = build_address(tn->tn_sys, tn, true); 2055 2056 /* lvalue to rvalue */ 2057 if (tn->tn_lvalue) { 2058 type_t *tp = expr_dup_type(tn->tn_type); 2059 /* C99 6.3.2.1p2 sentence 2 says to remove the qualifiers. */ 2060 tp->t_const = tp->t_volatile = false; 2061 tn = build_op(LOAD, tn->tn_sys, tp, tn, NULL); 2062 } 2063 2064 return tn; 2065 } 2066 2067 const tnode_t * 2068 before_conversion(const tnode_t *tn) 2069 { 2070 while (tn->tn_op == CVT && !tn->tn_cast) 2071 tn = tn->tn_left; 2072 return tn; 2073 } 2074 2075 /* 2076 * Most errors required by ANSI C are reported in struct_or_union_member(). 2077 * Here we only check for totally wrong things. 2078 */ 2079 static bool 2080 typeok_point(const tnode_t *ln, const type_t *ltp, tspec_t lt) 2081 { 2082 if (is_struct_or_union(lt)) 2083 return true; 2084 2085 if (lt == FUNC || lt == VOID || ltp->t_bitfield) 2086 goto wrong; 2087 2088 /* 2089 * Some C dialects from before C90 tolerated any lvalue on the 2090 * left-hand side of the '.' operator, allowing things like 2091 * char st[100]; st.st_mtime, assuming that the member 'st_mtime' 2092 * only occurred in a single struct; see typeok_arrow. 2093 */ 2094 if (ln->tn_lvalue) 2095 return true; 2096 2097 wrong: 2098 /* With allow_c90 we already got an error */ 2099 if (!allow_c90) 2100 /* unacceptable operand of '%s' */ 2101 error(111, op_name(POINT)); 2102 2103 return false; 2104 } 2105 2106 static bool 2107 typeok_arrow(tspec_t lt) 2108 { 2109 /* 2110 * C1978 Appendix A 14.1 says: <quote>In fact, any lvalue is allowed 2111 * before '.', and that lvalue is then assumed to have the form of 2112 * the structure of which the name of the right is a member. [...] 2113 * Such constructions are non-portable.</quote> 2114 */ 2115 if (lt == PTR || (!allow_c90 && is_integer(lt))) 2116 return true; 2117 2118 /* With allow_c90 we already got an error */ 2119 if (!allow_c90) 2120 /* unacceptable operand of '%s' */ 2121 error(111, op_name(ARROW)); 2122 return false; 2123 } 2124 2125 static bool 2126 typeok_incdec(op_t op, const tnode_t *tn, const type_t *tp) 2127 { 2128 /* operand has scalar type (checked in typeok) */ 2129 if (!tn->tn_lvalue) { 2130 if (tn->tn_op == CVT && tn->tn_cast && 2131 tn->tn_left->tn_op == LOAD) { 2132 /* a cast does not yield an lvalue */ 2133 error(163); 2134 } 2135 /* %soperand of '%s' must be lvalue */ 2136 error(114, "", op_name(op)); 2137 return false; 2138 } 2139 if (tp->t_const && allow_c90) { 2140 /* %soperand of '%s' must be modifiable lvalue */ 2141 warning(115, "", op_name(op)); 2142 } 2143 return true; 2144 } 2145 2146 static bool 2147 typeok_address(op_t op, const tnode_t *tn, const type_t *tp, tspec_t t) 2148 { 2149 if (t == ARRAY || t == FUNC) { 2150 /* ok, a warning comes later (in build_address()) */ 2151 } else if (!tn->tn_lvalue) { 2152 if (tn->tn_op == CVT && tn->tn_cast && 2153 tn->tn_left->tn_op == LOAD) { 2154 /* a cast does not yield an lvalue */ 2155 error(163); 2156 } 2157 /* %soperand of '%s' must be lvalue */ 2158 error(114, "", op_name(op)); 2159 return false; 2160 } else if (is_scalar(t)) { 2161 if (tp->t_bitfield) { 2162 /* cannot take address of bit-field */ 2163 error(112); 2164 return false; 2165 } 2166 } else if (t != STRUCT && t != UNION) { 2167 /* unacceptable operand of '%s' */ 2168 error(111, op_name(op)); 2169 return false; 2170 } 2171 if (tn->tn_op == NAME && tn->tn_sym->s_register) { 2172 /* cannot take address of register '%s' */ 2173 error(113, tn->tn_sym->s_name); 2174 return false; 2175 } 2176 return true; 2177 } 2178 2179 static bool 2180 typeok_indir(const type_t *tp, tspec_t t) 2181 { 2182 2183 if (t != PTR) { 2184 /* cannot dereference non-pointer type '%s' */ 2185 error(96, type_name(tp)); 2186 return false; 2187 } 2188 return true; 2189 } 2190 2191 static void 2192 warn_incompatible_types(op_t op, 2193 const type_t *ltp, tspec_t lt, 2194 const type_t *rtp, tspec_t rt) 2195 { 2196 bool binary = modtab[op].m_binary; 2197 2198 if (lt == VOID || (binary && rt == VOID)) { 2199 /* void type illegal in expression */ 2200 error(109); 2201 } else if (op == ASSIGN) { 2202 /* cannot assign to '%s' from '%s' */ 2203 error(171, type_name(ltp), type_name(rtp)); 2204 } else if (binary) { 2205 /* operands of '%s' have incompatible types '%s' and '%s' */ 2206 error(107, op_name(op), type_name(ltp), type_name(rtp)); 2207 } else { 2208 lint_assert(rt == NO_TSPEC); 2209 /* operand of '%s' has invalid type '%s' */ 2210 error(108, op_name(op), type_name(ltp)); 2211 } 2212 } 2213 2214 static bool 2215 typeok_plus(op_t op, 2216 const type_t *ltp, tspec_t lt, 2217 const type_t *rtp, tspec_t rt) 2218 { 2219 /* operands have scalar types (checked in typeok) */ 2220 if ((lt == PTR && !is_integer(rt)) || (rt == PTR && !is_integer(lt))) { 2221 warn_incompatible_types(op, ltp, lt, rtp, rt); 2222 return false; 2223 } 2224 return true; 2225 } 2226 2227 static bool 2228 typeok_minus(op_t op, 2229 const type_t *ltp, tspec_t lt, 2230 const type_t *rtp, tspec_t rt) 2231 { 2232 /* operands have scalar types (checked in typeok) */ 2233 if ((lt == PTR && rt != PTR && !is_integer(rt)) || 2234 (lt != PTR && rt == PTR)) { 2235 warn_incompatible_types(op, ltp, lt, rtp, rt); 2236 return false; 2237 } 2238 if (lt == PTR && rt == PTR && 2239 !types_compatible(ltp->t_subt, rtp->t_subt, true, false, NULL)) { 2240 /* illegal pointer subtraction */ 2241 error(116); 2242 } 2243 return true; 2244 } 2245 2246 static void 2247 typeok_shr(op_t op, 2248 const tnode_t *ln, tspec_t lt, 2249 const tnode_t *rn, tspec_t rt) 2250 { 2251 tspec_t olt = before_conversion(ln)->tn_type->t_tspec; 2252 tspec_t ort = before_conversion(rn)->tn_type->t_tspec; 2253 2254 /* operands have integer types (checked in typeok) */ 2255 if (pflag && !is_uinteger(olt)) { 2256 integer_constraints lc = ic_expr(ln); 2257 if (!ic_maybe_signed(ln->tn_type, &lc)) 2258 return; 2259 2260 /* 2261 * The left operand is signed. This means that 2262 * the operation is (possibly) nonportable. 2263 */ 2264 if (ln->tn_op != CON) { 2265 /* bitwise '%s' on signed value possibly nonportable */ 2266 warning(117, op_name(op)); 2267 } else if (ln->tn_val.u.integer < 0) { 2268 /* bitwise '%s' on signed value nonportable */ 2269 warning(120, op_name(op)); 2270 } 2271 } else if (allow_trad && allow_c90 && 2272 !is_uinteger(olt) && is_uinteger(ort)) { 2273 /* The left operand would become unsigned in traditional C. */ 2274 if (hflag && (ln->tn_op != CON || ln->tn_val.u.integer < 0)) { 2275 /* semantics of '%s' change in ANSI C; use ... */ 2276 warning(118, op_name(op)); 2277 } 2278 } else if (allow_trad && allow_c90 && 2279 !is_uinteger(olt) && !is_uinteger(ort) && 2280 portable_rank_cmp(lt, rt) < 0) { 2281 /* 2282 * In traditional C, the left operand would be extended 2283 * (possibly sign-extended) and then shifted. 2284 */ 2285 if (hflag && (ln->tn_op != CON || ln->tn_val.u.integer < 0)) { 2286 /* semantics of '%s' change in ANSI C; use ... */ 2287 warning(118, op_name(op)); 2288 } 2289 } 2290 } 2291 2292 static void 2293 typeok_shl(op_t op, tspec_t lt, tspec_t rt) 2294 { 2295 /* 2296 * C90 does not perform balancing for shift operations, 2297 * but traditional C does. If the width of the right operand 2298 * is greater than the width of the left operand, then in 2299 * traditional C the left operand would be extended to the 2300 * width of the right operand. For SHL this may result in 2301 * different results. 2302 */ 2303 if (portable_rank_cmp(lt, rt) < 0) { 2304 /* 2305 * XXX If both operands are constant, make sure 2306 * that there is really a difference between 2307 * ANSI C and traditional C. 2308 */ 2309 if (hflag && allow_trad && allow_c90) 2310 /* semantics of '%s' change in ANSI C; use ... */ 2311 warning(118, op_name(op)); 2312 } 2313 } 2314 2315 static void 2316 typeok_shift(const type_t *ltp, tspec_t lt, const tnode_t *rn, tspec_t rt) 2317 { 2318 if (rn->tn_op != CON) 2319 return; 2320 2321 if (!is_uinteger(rt) && rn->tn_val.u.integer < 0) { 2322 /* negative shift */ 2323 warning(121); 2324 } else if ((uint64_t)rn->tn_val.u.integer == size_in_bits(lt)) { 2325 /* shift amount %u equals bit-size of '%s' */ 2326 warning(267, (unsigned)rn->tn_val.u.integer, type_name(ltp)); 2327 } else if ((uint64_t)rn->tn_val.u.integer > size_in_bits(lt)) { 2328 /* shift amount %llu is greater than bit-size %llu of '%s' */ 2329 warning(122, (unsigned long long)rn->tn_val.u.integer, 2330 (unsigned long long)size_in_bits(lt), 2331 tspec_name(lt)); 2332 } 2333 } 2334 2335 static bool 2336 is_typeok_eq(const tnode_t *ln, tspec_t lt, const tnode_t *rn, tspec_t rt) 2337 { 2338 if (lt == PTR && is_null_pointer(rn)) 2339 return true; 2340 if (rt == PTR && is_null_pointer(ln)) 2341 return true; 2342 return false; 2343 } 2344 2345 /* 2346 * Called if incompatible pointer types are detected. 2347 * Print an appropriate warning. 2348 */ 2349 static void 2350 warn_incompatible_pointers(op_t op, const type_t *ltp, const type_t *rtp) 2351 { 2352 lint_assert(ltp->t_tspec == PTR); 2353 lint_assert(rtp->t_tspec == PTR); 2354 2355 tspec_t lt = ltp->t_subt->t_tspec; 2356 tspec_t rt = rtp->t_subt->t_tspec; 2357 2358 if (is_struct_or_union(lt) && is_struct_or_union(rt)) { 2359 if (op == RETURN) { 2360 /* illegal structure pointer combination */ 2361 warning(244); 2362 } else { 2363 /* incompatible structure pointers: '%s' '%s' '%s' */ 2364 warning(245, type_name(ltp), 2365 op_name(op), type_name(rtp)); 2366 } 2367 } else { 2368 if (op == RETURN) { 2369 /* illegal combination of '%s' and '%s' */ 2370 warning(184, type_name(ltp), type_name(rtp)); 2371 } else { 2372 /* illegal combination of '%s' and '%s', op '%s' */ 2373 warning(124, 2374 type_name(ltp), type_name(rtp), op_name(op)); 2375 } 2376 } 2377 } 2378 2379 static void 2380 check_pointer_comparison(op_t op, const tnode_t *ln, const tnode_t *rn) 2381 { 2382 type_t *ltp = ln->tn_type, *rtp = rn->tn_type; 2383 tspec_t lst = ltp->t_subt->t_tspec, rst = rtp->t_subt->t_tspec; 2384 2385 if (lst == VOID || rst == VOID) { 2386 /* TODO: C99 behaves like C90 here. */ 2387 if ((!allow_trad && !allow_c99) && 2388 (lst == FUNC || rst == FUNC)) { 2389 /* (void *)0 is already handled in typeok() */ 2390 const char *lsts, *rsts; 2391 *(lst == FUNC ? &lsts : &rsts) = "function pointer"; 2392 *(lst == VOID ? &lsts : &rsts) = "'void *'"; 2393 /* ANSI C forbids comparison of %s with %s */ 2394 warning(274, lsts, rsts); 2395 } 2396 return; 2397 } 2398 2399 if (!types_compatible(ltp->t_subt, rtp->t_subt, true, false, NULL)) { 2400 warn_incompatible_pointers(op, ltp, rtp); 2401 return; 2402 } 2403 2404 if (lst == FUNC && rst == FUNC) { 2405 /* TODO: C99 behaves like C90 here, see C99 6.5.8p2. */ 2406 if ((!allow_trad && !allow_c99) && op != EQ && op != NE) 2407 /* ANSI C forbids ordered comparisons of ... */ 2408 warning(125); 2409 } 2410 } 2411 2412 static bool 2413 typeok_compare(op_t op, 2414 const tnode_t *ln, const type_t *ltp, tspec_t lt, 2415 const tnode_t *rn, const type_t *rtp, tspec_t rt) 2416 { 2417 if (lt == PTR && rt == PTR) { 2418 check_pointer_comparison(op, ln, rn); 2419 return true; 2420 } 2421 2422 if (lt != PTR && rt != PTR) 2423 return true; 2424 2425 if (!is_integer(lt) && !is_integer(rt)) { 2426 warn_incompatible_types(op, ltp, lt, rtp, rt); 2427 return false; 2428 } 2429 2430 const char *lx = lt == PTR ? "pointer" : "integer"; 2431 const char *rx = rt == PTR ? "pointer" : "integer"; 2432 /* illegal combination of %s '%s' and %s '%s', op '%s' */ 2433 warning(123, lx, type_name(ltp), rx, type_name(rtp), op_name(op)); 2434 return true; 2435 } 2436 2437 static bool 2438 typeok_quest(tspec_t lt, const tnode_t *rn) 2439 { 2440 if (!is_scalar(lt)) { 2441 /* first operand of '?' must have scalar type */ 2442 error(170); 2443 return false; 2444 } 2445 lint_assert(before_conversion(rn)->tn_op == COLON); 2446 return true; 2447 } 2448 2449 static void 2450 typeok_colon_pointer(const type_t *ltp, const type_t *rtp) 2451 { 2452 type_t *lstp = ltp->t_subt; 2453 type_t *rstp = rtp->t_subt; 2454 tspec_t lst = lstp->t_tspec; 2455 tspec_t rst = rstp->t_tspec; 2456 2457 if ((lst == VOID && rst == FUNC) || (lst == FUNC && rst == VOID)) { 2458 /* (void *)0 is handled in typeok_colon */ 2459 /* TODO: C99 behaves like C90 here. */ 2460 if (!allow_trad && !allow_c99) 2461 /* ANSI C forbids conversion of %s to %s, op %s */ 2462 warning(305, "function pointer", "'void *'", 2463 op_name(COLON)); 2464 return; 2465 } 2466 2467 if (pointer_types_are_compatible(lstp, rstp, true)) 2468 return; 2469 if (!types_compatible(lstp, rstp, true, false, NULL)) 2470 warn_incompatible_pointers(COLON, ltp, rtp); 2471 } 2472 2473 static bool 2474 typeok_colon(const tnode_t *ln, const type_t *ltp, tspec_t lt, 2475 const tnode_t *rn, const type_t *rtp, tspec_t rt) 2476 { 2477 2478 if (is_arithmetic(lt) && is_arithmetic(rt)) 2479 return true; 2480 if (lt == BOOL && rt == BOOL) 2481 return true; 2482 2483 if (lt == STRUCT && rt == STRUCT && ltp->t_sou == rtp->t_sou) 2484 return true; 2485 if (lt == UNION && rt == UNION && ltp->t_sou == rtp->t_sou) 2486 return true; 2487 2488 if (lt == PTR && is_null_pointer(rn)) 2489 return true; 2490 if (rt == PTR && is_null_pointer(ln)) 2491 return true; 2492 2493 if ((lt == PTR && is_integer(rt)) || (is_integer(lt) && rt == PTR)) { 2494 const char *lx = lt == PTR ? "pointer" : "integer"; 2495 const char *rx = rt == PTR ? "pointer" : "integer"; 2496 /* illegal combination of %s '%s' and %s '%s', op '%s' */ 2497 warning(123, lx, type_name(ltp), 2498 rx, type_name(rtp), op_name(COLON)); 2499 return true; 2500 } 2501 2502 if (lt == VOID || rt == VOID) { 2503 if (lt != VOID || rt != VOID) 2504 /* incompatible types '%s' and '%s' in conditional */ 2505 warning(126, type_name(ltp), type_name(rtp)); 2506 return true; 2507 } 2508 2509 if (lt == PTR && rt == PTR) { 2510 typeok_colon_pointer(ltp, rtp); 2511 return true; 2512 } 2513 2514 /* incompatible types '%s' and '%s' in conditional */ 2515 error(126, type_name(ltp), type_name(rtp)); 2516 return false; 2517 } 2518 2519 /* 2520 * Returns true if the given structure or union has a constant member 2521 * (maybe recursively). 2522 */ 2523 static bool 2524 has_constant_member(const type_t *tp) 2525 { 2526 lint_assert(is_struct_or_union(tp->t_tspec)); 2527 2528 for (sym_t *m = tp->t_sou->sou_first_member; 2529 m != NULL; m = m->s_next) { 2530 const type_t *mtp = m->s_type; 2531 if (mtp->t_const) 2532 return true; 2533 if (is_struct_or_union(mtp->t_tspec) && 2534 has_constant_member(mtp)) 2535 return true; 2536 } 2537 return false; 2538 } 2539 2540 static bool 2541 typeok_assign(op_t op, const tnode_t *ln, const type_t *ltp, tspec_t lt) 2542 { 2543 if (op == RETURN || op == INIT || op == FARG) 2544 return true; 2545 2546 if (!ln->tn_lvalue) { 2547 if (ln->tn_op == CVT && ln->tn_cast && 2548 ln->tn_left->tn_op == LOAD) { 2549 /* a cast does not yield an lvalue */ 2550 error(163); 2551 } 2552 /* %soperand of '%s' must be lvalue */ 2553 error(114, "left ", op_name(op)); 2554 return false; 2555 } else if (ltp->t_const 2556 || (is_struct_or_union(lt) && has_constant_member(ltp))) { 2557 if (allow_c90) 2558 /* %soperand of '%s' must be modifiable lvalue */ 2559 warning(115, "left ", op_name(op)); 2560 } 2561 return true; 2562 } 2563 2564 /* Check the types using the information from modtab[]. */ 2565 static bool 2566 typeok_scalar(op_t op, const mod_t *mp, 2567 const type_t *ltp, tspec_t lt, 2568 const type_t *rtp, tspec_t rt) 2569 { 2570 if (mp->m_takes_bool && lt == BOOL && rt == BOOL) 2571 return true; 2572 if (mp->m_requires_integer) { 2573 if (!is_integer(lt) || (mp->m_binary && !is_integer(rt))) { 2574 warn_incompatible_types(op, ltp, lt, rtp, rt); 2575 return false; 2576 } 2577 } else if (mp->m_requires_integer_or_complex) { 2578 if ((!is_integer(lt) && !is_complex(lt)) || 2579 (mp->m_binary && (!is_integer(rt) && !is_complex(rt)))) { 2580 warn_incompatible_types(op, ltp, lt, rtp, rt); 2581 return false; 2582 } 2583 } else if (mp->m_requires_scalar) { 2584 if (!is_scalar(lt) || (mp->m_binary && !is_scalar(rt))) { 2585 warn_incompatible_types(op, ltp, lt, rtp, rt); 2586 return false; 2587 } 2588 } else if (mp->m_requires_arith) { 2589 if (!is_arithmetic(lt) || 2590 (mp->m_binary && !is_arithmetic(rt))) { 2591 warn_incompatible_types(op, ltp, lt, rtp, rt); 2592 return false; 2593 } 2594 } 2595 return true; 2596 } 2597 2598 static void 2599 check_assign_void_pointer(op_t op, int arg, 2600 tspec_t lt, tspec_t lst, 2601 tspec_t rt, tspec_t rst) 2602 { 2603 2604 if (!(lt == PTR && rt == PTR && (lst == VOID || rst == VOID))) 2605 return; 2606 /* two pointers, at least one pointer to void */ 2607 2608 /* TODO: C99 behaves like C90 here. */ 2609 if (!((!allow_trad && !allow_c99) && (lst == FUNC || rst == FUNC))) 2610 return; 2611 /* comb. of ptr to func and ptr to void */ 2612 2613 const char *lts, *rts; 2614 *(lst == FUNC ? <s : &rts) = "function pointer"; 2615 *(lst == VOID ? <s : &rts) = "'void *'"; 2616 2617 switch (op) { 2618 case INIT: 2619 case RETURN: 2620 /* ANSI C forbids conversion of %s to %s */ 2621 warning(303, rts, lts); 2622 break; 2623 case FARG: 2624 /* ANSI C forbids conversion of %s to %s, arg #%d */ 2625 warning(304, rts, lts, arg); 2626 break; 2627 default: 2628 /* ANSI C forbids conversion of %s to %s, op %s */ 2629 warning(305, rts, lts, op_name(op)); 2630 break; 2631 } 2632 } 2633 2634 static bool 2635 is_direct_function_call(const tnode_t *tn, const char **out_name) 2636 { 2637 2638 if (!(tn->tn_op == CALL && 2639 tn->tn_left->tn_op == ADDR && 2640 tn->tn_left->tn_left->tn_op == NAME)) 2641 return false; 2642 2643 *out_name = tn->tn_left->tn_left->tn_sym->s_name; 2644 return true; 2645 } 2646 2647 static bool 2648 is_unconst_function(const char *name) 2649 { 2650 2651 return strcmp(name, "memchr") == 0 || 2652 strcmp(name, "strchr") == 0 || 2653 strcmp(name, "strpbrk") == 0 || 2654 strcmp(name, "strrchr") == 0 || 2655 strcmp(name, "strstr") == 0; 2656 } 2657 2658 static bool 2659 is_const_char_pointer(const tnode_t *tn) 2660 { 2661 /* 2662 * For traditional reasons, C99 6.4.5p5 defines that string literals 2663 * have type 'char[]'. They are often implicitly converted to 2664 * 'char *', for example when they are passed as function arguments. 2665 * 2666 * C99 6.4.5p6 further defines that modifying a string that is 2667 * constructed from a string literal invokes undefined behavior. 2668 * 2669 * Out of these reasons, string literals are treated as 'effectively 2670 * const' here. 2671 */ 2672 if (tn->tn_op == CVT && 2673 tn->tn_left->tn_op == ADDR && 2674 tn->tn_left->tn_left->tn_op == STRING) 2675 return true; 2676 2677 const type_t *tp = before_conversion(tn)->tn_type; 2678 return tp->t_tspec == PTR && 2679 tp->t_subt->t_tspec == CHAR && 2680 tp->t_subt->t_const; 2681 } 2682 2683 static bool 2684 is_first_arg_const_char_pointer(const tnode_t *tn) 2685 { 2686 const tnode_t *an = tn->tn_right; 2687 if (an == NULL) 2688 return false; 2689 2690 while (an->tn_right != NULL) 2691 an = an->tn_right; 2692 return is_const_char_pointer(an->tn_left); 2693 } 2694 2695 static bool 2696 is_const_pointer(const tnode_t *tn) 2697 { 2698 const type_t *tp = before_conversion(tn)->tn_type; 2699 return tp->t_tspec == PTR && tp->t_subt->t_const; 2700 } 2701 2702 static bool 2703 is_second_arg_const_pointer(const tnode_t *tn) 2704 { 2705 const tnode_t *an = tn->tn_right; 2706 if (an == NULL || an->tn_right == NULL) 2707 return false; 2708 2709 while (an->tn_right->tn_right != NULL) 2710 an = an->tn_right; 2711 return is_const_pointer(an->tn_left); 2712 } 2713 2714 static void 2715 check_unconst_function(const type_t *lstp, const tnode_t *rn) 2716 { 2717 const char *function_name; 2718 2719 if (lstp->t_tspec == CHAR && !lstp->t_const && 2720 is_direct_function_call(rn, &function_name) && 2721 is_unconst_function(function_name) && 2722 is_first_arg_const_char_pointer(rn)) { 2723 /* call to '%s' effectively discards 'const' from argument */ 2724 warning(346, function_name); 2725 } 2726 2727 if (!lstp->t_const && 2728 is_direct_function_call(rn, &function_name) && 2729 strcmp(function_name, "bsearch") == 0 && 2730 is_second_arg_const_pointer(rn)) { 2731 /* call to '%s' effectively discards 'const' from argument */ 2732 warning(346, function_name); 2733 } 2734 } 2735 2736 static bool 2737 check_assign_void_pointer_compat(op_t op, int arg, 2738 const type_t *const ltp, tspec_t const lt, 2739 const type_t *const lstp, tspec_t const lst, 2740 const tnode_t *const rn, 2741 const type_t *const rtp, tspec_t const rt, 2742 const type_t *const rstp, tspec_t const rst) 2743 { 2744 if (!(lt == PTR && rt == PTR && (lst == VOID || rst == VOID || 2745 types_compatible(lstp, rstp, 2746 true, false, NULL)))) 2747 return false; 2748 2749 /* compatible pointer types (qualifiers ignored) */ 2750 if (allow_c90 && 2751 ((!lstp->t_const && rstp->t_const) || 2752 (!lstp->t_volatile && rstp->t_volatile))) { 2753 /* left side has not all qualifiers of right */ 2754 switch (op) { 2755 case INIT: 2756 case RETURN: 2757 /* incompatible pointer types to '%s' and '%s' */ 2758 warning(182, type_name(lstp), type_name(rstp)); 2759 break; 2760 case FARG: 2761 /* converting '%s' to incompatible '%s' ... */ 2762 warning(153, 2763 type_name(rtp), type_name(ltp), arg); 2764 break; 2765 default: 2766 /* operands of '%s' have incompatible pointer ... */ 2767 warning(128, op_name(op), 2768 type_name(lstp), type_name(rstp)); 2769 break; 2770 } 2771 } 2772 2773 if (allow_c90) 2774 check_unconst_function(lstp, rn); 2775 2776 return true; 2777 } 2778 2779 static bool 2780 check_assign_pointer_integer(op_t op, int arg, 2781 const type_t *const ltp, tspec_t const lt, 2782 const type_t *const rtp, tspec_t const rt) 2783 { 2784 2785 if (!((lt == PTR && is_integer(rt)) || (is_integer(lt) && rt == PTR))) 2786 return false; 2787 2788 const char *lx = lt == PTR ? "pointer" : "integer"; 2789 const char *rx = rt == PTR ? "pointer" : "integer"; 2790 2791 switch (op) { 2792 case INIT: 2793 case RETURN: 2794 /* illegal combination of %s '%s' and %s '%s' */ 2795 warning(183, lx, type_name(ltp), rx, type_name(rtp)); 2796 break; 2797 case FARG: 2798 /* illegal combination of %s '%s' and %s '%s', arg #%d */ 2799 warning(154, 2800 lx, type_name(ltp), rx, type_name(rtp), arg); 2801 break; 2802 default: 2803 /* illegal combination of %s '%s' and %s '%s', op '%s' */ 2804 warning(123, 2805 lx, type_name(ltp), rx, type_name(rtp), op_name(op)); 2806 break; 2807 } 2808 return true; 2809 } 2810 2811 static bool 2812 check_assign_pointer(op_t op, int arg, 2813 const type_t *ltp, tspec_t lt, 2814 const type_t *rtp, tspec_t rt) 2815 { 2816 if (!(lt == PTR && rt == PTR)) 2817 return false; 2818 2819 if (op == FARG) 2820 /* converting '%s' to incompatible '%s' for ... */ 2821 warning(153, type_name(rtp), type_name(ltp), arg); 2822 else 2823 warn_incompatible_pointers(op, ltp, rtp); 2824 return true; 2825 } 2826 2827 static void 2828 warn_assign(op_t op, int arg, 2829 const type_t *ltp, tspec_t lt, 2830 const type_t *rtp, tspec_t rt) 2831 { 2832 switch (op) { 2833 case INIT: 2834 /* cannot initialize '%s' from '%s' */ 2835 error(185, type_name(ltp), type_name(rtp)); 2836 break; 2837 case RETURN: 2838 /* function has return type '%s' but returns '%s' */ 2839 error(211, type_name(ltp), type_name(rtp)); 2840 break; 2841 case FARG: 2842 /* passing '%s' to incompatible '%s', arg #%d */ 2843 warning(155, type_name(rtp), type_name(ltp), arg); 2844 break; 2845 default: 2846 warn_incompatible_types(op, ltp, lt, rtp, rt); 2847 break; 2848 } 2849 } 2850 2851 /* 2852 * Checks type compatibility for ASSIGN, INIT, FARG and RETURN 2853 * and prints warnings/errors if necessary. 2854 * Returns whether the types are (almost) compatible. 2855 */ 2856 static bool 2857 check_assign_types_compatible(op_t op, int arg, 2858 const tnode_t *ln, const tnode_t *rn) 2859 { 2860 tspec_t lt, rt, lst = NO_TSPEC, rst = NO_TSPEC; 2861 type_t *ltp, *rtp, *lstp = NULL, *rstp = NULL; 2862 2863 if ((lt = (ltp = ln->tn_type)->t_tspec) == PTR) 2864 lst = (lstp = ltp->t_subt)->t_tspec; 2865 if ((rt = (rtp = rn->tn_type)->t_tspec) == PTR) 2866 rst = (rstp = rtp->t_subt)->t_tspec; 2867 2868 if (lt == BOOL && is_scalar(rt)) /* C99 6.3.1.2 */ 2869 return true; 2870 2871 if (is_arithmetic(lt) && (is_arithmetic(rt) || rt == BOOL)) 2872 return true; 2873 2874 if (is_struct_or_union(lt) && is_struct_or_union(rt)) 2875 /* both are struct or union */ 2876 return ltp->t_sou == rtp->t_sou; 2877 2878 /* a null pointer may be assigned to any pointer */ 2879 if (lt == PTR && is_null_pointer(rn)) { 2880 if (is_integer(rn->tn_type->t_tspec)) 2881 /* implicit conversion from integer 0 to pointer ... */ 2882 query_message(15, type_name(ltp)); 2883 return true; 2884 } 2885 2886 check_assign_void_pointer(op, arg, lt, lst, rt, rst); 2887 2888 if (check_assign_void_pointer_compat(op, arg, 2889 ltp, lt, lstp, lst, rn, rtp, rt, rstp, rst)) 2890 return true; 2891 2892 if (check_assign_pointer_integer(op, arg, ltp, lt, rtp, rt)) 2893 return true; 2894 2895 if (check_assign_pointer(op, arg, ltp, lt, rtp, rt)) 2896 return true; 2897 2898 warn_assign(op, arg, ltp, lt, rtp, rt); 2899 return false; 2900 } 2901 2902 static bool 2903 has_side_effect(const tnode_t *tn) /* NOLINT(misc-no-recursion) */ 2904 { 2905 op_t op = tn->tn_op; 2906 2907 if (modtab[op].m_has_side_effect) 2908 return true; 2909 2910 if (op == CVT && tn->tn_type->t_tspec == VOID) 2911 return has_side_effect(tn->tn_left); 2912 2913 /* XXX: Why not has_side_effect(tn->tn_left) as well? */ 2914 if (op == LOGAND || op == LOGOR) 2915 return has_side_effect(tn->tn_right); 2916 2917 /* XXX: Why not has_side_effect(tn->tn_left) as well? */ 2918 if (op == QUEST) 2919 return has_side_effect(tn->tn_right); 2920 2921 if (op == COLON || op == COMMA) { 2922 return has_side_effect(tn->tn_left) || 2923 has_side_effect(tn->tn_right); 2924 } 2925 2926 return false; 2927 } 2928 2929 static bool 2930 is_void_cast(const tnode_t *tn) 2931 { 2932 2933 return tn->tn_op == CVT && tn->tn_cast && 2934 tn->tn_type->t_tspec == VOID; 2935 } 2936 2937 static bool 2938 is_local_symbol(const tnode_t *tn) 2939 { 2940 2941 return tn->tn_op == LOAD && 2942 tn->tn_left->tn_op == NAME && 2943 tn->tn_left->tn_sym->s_scl == AUTO; 2944 } 2945 2946 static bool 2947 is_int_constant_zero(const tnode_t *tn) 2948 { 2949 2950 return tn->tn_op == CON && 2951 tn->tn_type->t_tspec == INT && 2952 tn->tn_val.u.integer == 0; 2953 } 2954 2955 static void 2956 check_null_effect(const tnode_t *tn) 2957 { 2958 2959 if (hflag && 2960 !has_side_effect(tn) && 2961 !(is_void_cast(tn) && is_local_symbol(tn->tn_left)) && 2962 !(is_void_cast(tn) && is_int_constant_zero(tn->tn_left))) { 2963 /* expression has null effect */ 2964 warning(129); 2965 } 2966 } 2967 2968 /* 2969 * Check the types for specific operators and type combinations. 2970 * 2971 * At this point, the operands already conform to the type requirements of 2972 * the operator, such as being integer, floating or scalar. 2973 */ 2974 static bool 2975 typeok_op(op_t op, int arg, 2976 const tnode_t *ln, const type_t *ltp, tspec_t lt, 2977 const tnode_t *rn, const type_t *rtp, tspec_t rt) 2978 { 2979 switch (op) { 2980 case ARROW: 2981 return typeok_arrow(lt); 2982 case POINT: 2983 return typeok_point(ln, ltp, lt); 2984 case INCBEF: 2985 case DECBEF: 2986 case INCAFT: 2987 case DECAFT: 2988 return typeok_incdec(op, ln, ltp); 2989 case INDIR: 2990 return typeok_indir(ltp, lt); 2991 case ADDR: 2992 return typeok_address(op, ln, ltp, lt); 2993 case PLUS: 2994 return typeok_plus(op, ltp, lt, rtp, rt); 2995 case MINUS: 2996 return typeok_minus(op, ltp, lt, rtp, rt); 2997 case SHL: 2998 typeok_shl(op, lt, rt); 2999 goto shift; 3000 case SHR: 3001 typeok_shr(op, ln, lt, rn, rt); 3002 shift: 3003 typeok_shift(ltp, lt, rn, rt); 3004 break; 3005 case LT: 3006 case LE: 3007 case GT: 3008 case GE: 3009 compare: 3010 return typeok_compare(op, ln, ltp, lt, rn, rtp, rt); 3011 case EQ: 3012 case NE: 3013 if (is_typeok_eq(ln, lt, rn, rt)) 3014 break; 3015 goto compare; 3016 case QUEST: 3017 return typeok_quest(lt, rn); 3018 case COLON: 3019 return typeok_colon(ln, ltp, lt, rn, rtp, rt); 3020 case ASSIGN: 3021 case INIT: 3022 case FARG: 3023 case RETURN: 3024 if (!check_assign_types_compatible(op, arg, ln, rn)) 3025 return false; 3026 goto assign; 3027 case MULASS: 3028 case DIVASS: 3029 case MODASS: 3030 goto assign; 3031 case ADDASS: 3032 case SUBASS: 3033 if ((lt == PTR && !is_integer(rt)) || rt == PTR) { 3034 warn_incompatible_types(op, ltp, lt, rtp, rt); 3035 return false; 3036 } 3037 goto assign; 3038 case SHLASS: 3039 goto assign; 3040 case SHRASS: 3041 if (pflag && !is_uinteger(lt) && 3042 !(!allow_c90 && is_uinteger(rt))) { 3043 /* bitwise '%s' on signed value possibly nonportable */ 3044 warning(117, op_name(op)); 3045 } 3046 goto assign; 3047 case ANDASS: 3048 case XORASS: 3049 case ORASS: 3050 assign: 3051 return typeok_assign(op, ln, ltp, lt); 3052 case COMMA: 3053 if (!modtab[ln->tn_op].m_has_side_effect) 3054 check_null_effect(ln); 3055 break; 3056 default: 3057 break; 3058 } 3059 return true; 3060 } 3061 3062 /* Prints a warning if a strange operator is used on an enum type. */ 3063 static void 3064 check_bad_enum_operation(op_t op, const tnode_t *ln, const tnode_t *rn) 3065 { 3066 3067 if (!eflag) 3068 return; 3069 3070 /* Allow enum in array indices. */ 3071 if (op == PLUS && 3072 ((ln->tn_type->t_is_enum && rn->tn_type->t_tspec == PTR) || 3073 (rn->tn_type->t_is_enum && ln->tn_type->t_tspec == PTR))) { 3074 return; 3075 } 3076 3077 /* dubious operation '%s' on enum */ 3078 warning(241, op_name(op)); 3079 } 3080 3081 /* Prints a warning if an operator is applied to two different enum types. */ 3082 static void 3083 check_enum_type_mismatch(op_t op, int arg, const tnode_t *ln, const tnode_t *rn) 3084 { 3085 const mod_t *mp = &modtab[op]; 3086 3087 if (ln->tn_type->t_enum != rn->tn_type->t_enum) { 3088 switch (op) { 3089 case INIT: 3090 /* enum type mismatch between '%s' and '%s' in ... */ 3091 warning(210, 3092 type_name(ln->tn_type), type_name(rn->tn_type)); 3093 break; 3094 case FARG: 3095 /* function expects '%s', passing '%s' for arg #%d */ 3096 warning(156, 3097 type_name(ln->tn_type), type_name(rn->tn_type), 3098 arg); 3099 break; 3100 case RETURN: 3101 /* function has return type '%s' but returns '%s' */ 3102 warning(211, 3103 type_name(ln->tn_type), type_name(rn->tn_type)); 3104 break; 3105 default: 3106 /* enum type mismatch: '%s' '%s' '%s' */ 3107 warning(130, type_name(ln->tn_type), op_name(op), 3108 type_name(rn->tn_type)); 3109 break; 3110 } 3111 } else if (Pflag && eflag && mp->m_comparison && op != EQ && op != NE) 3112 /* operator '%s' assumes that '%s' is ordered */ 3113 warning(243, op_name(op), type_name(ln->tn_type)); 3114 } 3115 3116 /* Prints a warning if the operands mix between enum and integer. */ 3117 static void 3118 check_enum_int_mismatch(op_t op, int arg, const tnode_t *ln, const tnode_t *rn) 3119 { 3120 3121 if (!eflag) 3122 return; 3123 3124 switch (op) { 3125 case INIT: 3126 /* 3127 * Initialization with 0 is allowed. Otherwise, all implicit 3128 * initializations would need to be warned upon as well. 3129 */ 3130 if (!rn->tn_type->t_is_enum && rn->tn_op == CON && 3131 is_integer(rn->tn_type->t_tspec) && 3132 rn->tn_val.u.integer == 0) { 3133 return; 3134 } 3135 /* initialization of '%s' with '%s' */ 3136 warning(277, type_name(ln->tn_type), type_name(rn->tn_type)); 3137 break; 3138 case FARG: 3139 /* combination of '%s' and '%s', arg #%d */ 3140 warning(278, 3141 type_name(ln->tn_type), type_name(rn->tn_type), arg); 3142 break; 3143 case RETURN: 3144 /* combination of '%s' and '%s' in return */ 3145 warning(279, type_name(ln->tn_type), type_name(rn->tn_type)); 3146 break; 3147 default: 3148 /* combination of '%s' and '%s', op '%s' */ 3149 warning(242, type_name(ln->tn_type), type_name(rn->tn_type), 3150 op_name(op)); 3151 break; 3152 } 3153 } 3154 3155 static void 3156 typeok_enum(op_t op, const mod_t *mp, int arg, 3157 const tnode_t *ln, const type_t *ltp, 3158 const tnode_t *rn, const type_t *rtp) 3159 { 3160 if (mp->m_bad_on_enum && 3161 (ltp->t_is_enum || (mp->m_binary && rtp->t_is_enum))) { 3162 check_bad_enum_operation(op, ln, rn); 3163 } else if (mp->m_valid_on_enum && 3164 (ltp->t_is_enum && rtp != NULL && rtp->t_is_enum)) { 3165 check_enum_type_mismatch(op, arg, ln, rn); 3166 } else if (mp->m_valid_on_enum && 3167 (ltp->t_is_enum || (rtp != NULL && rtp->t_is_enum))) { 3168 check_enum_int_mismatch(op, arg, ln, rn); 3169 } 3170 } 3171 3172 /* Perform most type checks. Return whether the types are ok. */ 3173 bool 3174 typeok(op_t op, int arg, const tnode_t *ln, const tnode_t *rn) 3175 { 3176 3177 const mod_t *mp = &modtab[op]; 3178 3179 type_t *ltp = ln->tn_type; 3180 tspec_t lt = ltp->t_tspec; 3181 3182 type_t *rtp = mp->m_binary ? rn->tn_type : NULL; 3183 tspec_t rt = mp->m_binary ? rtp->t_tspec : NO_TSPEC; 3184 3185 if (Tflag && !typeok_scalar_strict_bool(op, mp, arg, ln, rn)) 3186 return false; 3187 if (!typeok_scalar(op, mp, ltp, lt, rtp, rt)) 3188 return false; 3189 3190 if (!typeok_op(op, arg, ln, ltp, lt, rn, rtp, rt)) 3191 return false; 3192 3193 typeok_enum(op, mp, arg, ln, ltp, rn, rtp); 3194 return true; 3195 } 3196 3197 /* In traditional C, keep unsigned and promote FLOAT to DOUBLE. */ 3198 static tspec_t 3199 promote_trad(tspec_t t) 3200 { 3201 3202 if (t == UCHAR || t == USHORT) 3203 return UINT; 3204 if (t == CHAR || t == SCHAR || t == SHORT) 3205 return INT; 3206 if (t == FLOAT) 3207 return DOUBLE; 3208 if (t == ENUM) 3209 return INT; 3210 return t; 3211 } 3212 3213 /* 3214 * C99 6.3.1.1p2 requires for types with lower rank than int that "If an int 3215 * can represent all the values of the original type, the value is converted 3216 * to an int; otherwise it is converted to an unsigned int", and that "All 3217 * other types are unchanged by the integer promotions". 3218 */ 3219 static tspec_t 3220 promote_c90(const tnode_t *tn, tspec_t t, bool farg) 3221 { 3222 if (tn->tn_type->t_bitfield) { 3223 unsigned int width = tn->tn_type->t_bit_field_width; 3224 unsigned int int_width = size_in_bits(INT); 3225 // XXX: What about _Bool bit-fields, since C99? 3226 if (width < int_width) 3227 return INT; 3228 if (width == int_width) 3229 return is_uinteger(t) ? UINT : INT; 3230 return t; 3231 } 3232 3233 if (t == CHAR || t == SCHAR) 3234 return INT; 3235 if (t == UCHAR) 3236 return size_in_bits(CHAR) < size_in_bits(INT) ? INT : UINT; 3237 if (t == SHORT) 3238 return INT; 3239 if (t == USHORT) 3240 return size_in_bits(SHORT) < size_in_bits(INT) ? INT : UINT; 3241 if (t == ENUM) 3242 return INT; 3243 if (farg && t == FLOAT) 3244 return DOUBLE; 3245 return t; 3246 } 3247 3248 /* 3249 * Performs the "integer promotions" (C99 6.3.1.1p2), which convert small 3250 * integer types to either int or unsigned int. 3251 * 3252 * If allow_c90 is unset or the operand is a function argument with no type 3253 * information (no prototype or variable # of args), converts float to double. 3254 */ 3255 tnode_t * 3256 promote(op_t op, bool farg, tnode_t *tn) 3257 { 3258 3259 tspec_t ot = tn->tn_type->t_tspec; 3260 if (!is_arithmetic(ot)) 3261 return tn; 3262 3263 tspec_t nt = allow_c90 ? promote_c90(tn, ot, farg) : promote_trad(ot); 3264 if (nt == ot) 3265 return tn; 3266 3267 type_t *ntp = expr_dup_type(tn->tn_type); 3268 ntp->t_tspec = nt; 3269 /* 3270 * Keep t_is_enum even though t_tspec gets converted from 3271 * ENUM to INT, so we are later able to check compatibility 3272 * of enum types. 3273 */ 3274 return convert(op, 0, ntp, tn); 3275 } 3276 3277 static void 3278 convert_integer_from_floating(op_t op, const type_t *tp, const tnode_t *tn) 3279 { 3280 3281 if (op == CVT) 3282 /* cast from floating point '%s' to integer '%s' */ 3283 query_message(2, type_name(tn->tn_type), type_name(tp)); 3284 else 3285 /* implicit conversion from floating point '%s' to ... */ 3286 query_message(1, type_name(tn->tn_type), type_name(tp)); 3287 } 3288 3289 static bool 3290 should_warn_about_prototype_conversion(tspec_t nt, 3291 tspec_t ot, const tnode_t *ptn) 3292 { 3293 3294 if (nt == ot) 3295 return false; 3296 3297 if (nt == ENUM && ot == INT) 3298 return false; 3299 3300 if (is_floating(nt) != is_floating(ot) || 3301 portable_rank_cmp(nt, ot) != 0) { 3302 /* representation and/or width change */ 3303 if (!is_integer(ot)) 3304 return true; 3305 /* 3306 * XXX: Investigate whether this rule makes sense; see 3307 * tests/usr.bin/xlint/lint1/platform_long.c. 3308 */ 3309 return portable_rank_cmp(ot, INT) > 0; 3310 } 3311 3312 if (!hflag) 3313 return false; 3314 3315 /* 3316 * If the types differ only in sign and the argument has the same 3317 * representation in both types, print no warning. 3318 */ 3319 if (ptn->tn_op == CON && is_integer(nt) && 3320 signed_type(nt) == signed_type(ot) && 3321 !msb(ptn->tn_val.u.integer, ot)) 3322 return false; 3323 3324 return true; 3325 } 3326 3327 /* 3328 * Warn if a prototype causes a type conversion that is different from what 3329 * would happen to the same argument in the absence of a prototype. This 3330 * check is intended for code that needs to stay compatible with pre-C90 C. 3331 * 3332 * Errors/warnings about illegal type combinations are already printed 3333 * in check_assign_types_compatible(). 3334 */ 3335 static void 3336 check_prototype_conversion(int arg, tspec_t nt, tspec_t ot, type_t *tp, 3337 tnode_t *tn) 3338 { 3339 3340 if (!is_arithmetic(nt) || !is_arithmetic(ot)) 3341 return; 3342 3343 /* 3344 * If the type of the formal parameter is char/short, a warning 3345 * would be useless, because functions declared the old style 3346 * can't expect char/short arguments. 3347 */ 3348 if (nt == CHAR || nt == SCHAR || nt == UCHAR || 3349 nt == SHORT || nt == USHORT) 3350 return; 3351 3352 /* apply the default promotion */ 3353 tnode_t *ptn = promote(NOOP, true, tn); 3354 ot = ptn->tn_type->t_tspec; 3355 3356 if (should_warn_about_prototype_conversion(nt, ot, ptn)) { 3357 /* argument %d is converted from '%s' to '%s' ... */ 3358 warning(259, arg, type_name(tn->tn_type), type_name(tp)); 3359 } 3360 } 3361 3362 /* 3363 * When converting a large integer type to a small integer type, in some 3364 * cases the value of the actual expression is further restricted than the 3365 * type bounds, such as in (expr & 0xFF) or (expr % 100) or (expr >> 24). 3366 */ 3367 static bool 3368 can_represent(const type_t *tp, const tnode_t *tn) 3369 { 3370 3371 debug_step("%s: type '%s'", __func__, type_name(tp)); 3372 debug_node(tn); 3373 3374 uint64_t nmask = value_bits(width_in_bits(tp)); 3375 if (!is_uinteger(tp->t_tspec)) 3376 nmask >>= 1; 3377 3378 integer_constraints c = ic_expr(tn); 3379 if ((~c.bclr & ~nmask) == 0) 3380 return true; 3381 3382 integer_constraints tpc = ic_any(tp); 3383 if (is_uinteger(tp->t_tspec) 3384 ? tpc.umin <= c.umin && tpc.umax >= c.umax 3385 : tpc.smin <= c.smin && tpc.smax >= c.smax) 3386 return true; 3387 3388 return false; 3389 } 3390 3391 static void 3392 convert_integer_from_integer(op_t op, int arg, tspec_t nt, tspec_t ot, 3393 type_t *tp, tnode_t *tn) 3394 { 3395 3396 if (tn->tn_op == CON) 3397 return; 3398 3399 if (op == CVT) 3400 return; 3401 3402 if (Pflag && pflag && aflag > 0 && 3403 portable_rank_cmp(nt, ot) > 0 && 3404 is_uinteger(nt) != is_uinteger(ot)) { 3405 if (op == FARG) { 3406 /* conversion to '%s' may sign-extend ... */ 3407 warning(297, type_name(tp), arg); 3408 } else { 3409 /* conversion to '%s' may sign-extend ... */ 3410 warning(131, type_name(tp)); 3411 } 3412 } 3413 3414 if (Pflag && portable_rank_cmp(nt, ot) > 0 && 3415 (tn->tn_op == PLUS || tn->tn_op == MINUS || tn->tn_op == MULT || 3416 tn->tn_op == SHL)) { 3417 /* suggest cast from '%s' to '%s' on op '%s' to ... */ 3418 warning(324, type_name(gettyp(ot)), type_name(tp), 3419 op_name(tn->tn_op)); 3420 } 3421 3422 if (aflag > 0 && 3423 portable_rank_cmp(nt, ot) < 0 && 3424 (portable_rank_cmp(ot, LONG) >= 0 || aflag > 1) && 3425 // XXX: The portable_rank_cmp above aims at portable mode, 3426 // independent of the current platform, while can_represent acts 3427 // on the actual type sizes from the current platform. This mix 3428 // is inconsistent, but anything else would make the exact 3429 // conditions too complicated to grasp. 3430 !can_represent(tp, tn)) { 3431 if (op == FARG) { 3432 /* conversion from '%s' to '%s' may lose ... */ 3433 warning(298, 3434 type_name(tn->tn_type), type_name(tp), arg); 3435 } else { 3436 /* conversion from '%s' to '%s' may lose accuracy */ 3437 warning(132, 3438 type_name(tn->tn_type), type_name(tp)); 3439 } 3440 } 3441 3442 if (any_query_enabled && is_uinteger(nt) != is_uinteger(ot)) 3443 /* implicit conversion changes sign from '%s' to '%s' */ 3444 query_message(3, type_name(tn->tn_type), type_name(tp)); 3445 } 3446 3447 static void 3448 convert_integer_from_pointer(op_t op, tspec_t nt, type_t *tp, tnode_t *tn) 3449 { 3450 3451 if (tn->tn_op == CON) 3452 return; 3453 if (op != CVT) 3454 return; /* We already got an error. */ 3455 if (portable_rank_cmp(nt, PTR) >= 0) 3456 return; 3457 3458 if (pflag && size_in_bits(nt) >= size_in_bits(PTR)) { 3459 /* conversion of pointer to '%s' may lose bits */ 3460 warning(134, type_name(tp)); 3461 } else { 3462 /* conversion of pointer to '%s' loses bits */ 3463 warning(133, type_name(tp)); 3464 } 3465 } 3466 3467 static bool 3468 struct_starts_with(const type_t *struct_tp, const type_t *member_tp) 3469 { 3470 3471 return struct_tp->t_sou->sou_first_member != NULL && 3472 types_compatible(struct_tp->t_sou->sou_first_member->s_type, 3473 member_tp, true, false, NULL); 3474 } 3475 3476 static bool 3477 is_byte_array(const type_t *tp) 3478 { 3479 3480 return tp->t_tspec == ARRAY && 3481 (tp->t_subt->t_tspec == CHAR || tp->t_subt->t_tspec == UCHAR); 3482 } 3483 3484 static bool 3485 union_contains(const type_t *utp, const type_t *mtp) 3486 { 3487 for (const sym_t *mem = utp->t_sou->sou_first_member; 3488 mem != NULL; mem = mem->s_next) { 3489 if (types_compatible(mem->s_type, mtp, true, false, NULL)) 3490 return true; 3491 } 3492 return false; 3493 } 3494 3495 static bool 3496 should_warn_about_pointer_cast(const type_t *nstp, tspec_t nst, 3497 const type_t *ostp, tspec_t ost) 3498 { 3499 3500 while (nst == ARRAY) 3501 nstp = nstp->t_subt, nst = nstp->t_tspec; 3502 while (ost == ARRAY) 3503 ostp = ostp->t_subt, ost = ostp->t_tspec; 3504 3505 if (nst == STRUCT && ost == STRUCT && 3506 (struct_starts_with(nstp, ostp) || 3507 struct_starts_with(ostp, nstp))) 3508 return false; 3509 3510 if (is_incomplete(nstp) || is_incomplete(ostp)) 3511 return false; 3512 3513 if (nst == CHAR || nst == UCHAR) 3514 return false; /* for the sake of traditional C code */ 3515 if (ost == CHAR || ost == UCHAR) 3516 return false; /* for the sake of traditional C code */ 3517 3518 /* Allow cast between pointers to sockaddr variants. */ 3519 if (nst == STRUCT && ost == STRUCT) { 3520 const sym_t *nmem = nstp->t_sou->sou_first_member; 3521 const sym_t *omem = ostp->t_sou->sou_first_member; 3522 while (nmem != NULL && omem != NULL && 3523 types_compatible(nmem->s_type, omem->s_type, 3524 true, false, NULL)) 3525 nmem = nmem->s_next, omem = omem->s_next; 3526 if (nmem != NULL && is_byte_array(nmem->s_type)) 3527 return false; 3528 if (omem != NULL && is_byte_array(omem->s_type)) 3529 return false; 3530 if (nmem == NULL && omem == NULL) 3531 return false; 3532 } 3533 3534 if (nst == UNION || ost == UNION) { 3535 const type_t *union_tp = nst == UNION ? nstp : ostp; 3536 const type_t *other_tp = nst == UNION ? ostp : nstp; 3537 if (union_contains(union_tp, other_tp)) 3538 return false; 3539 } 3540 3541 if (is_struct_or_union(nst) && is_struct_or_union(ost)) 3542 return nstp->t_sou != ostp->t_sou; 3543 3544 enum rank_kind rk1 = type_properties(nst)->tt_rank_kind; 3545 enum rank_kind rk2 = type_properties(ost)->tt_rank_kind; 3546 if (rk1 != rk2 || rk1 == RK_NONE) 3547 return true; 3548 3549 return portable_rank_cmp(nst, ost) != 0; 3550 } 3551 3552 static void 3553 convert_pointer_from_pointer(type_t *ntp, tnode_t *tn) 3554 { 3555 const type_t *nstp = ntp->t_subt; 3556 const type_t *otp = tn->tn_type; 3557 const type_t *ostp = otp->t_subt; 3558 tspec_t nst = nstp->t_tspec; 3559 tspec_t ost = ostp->t_tspec; 3560 3561 if (nst == VOID || ost == VOID) { 3562 /* TODO: C99 behaves like C90 here. */ 3563 if ((!allow_trad && !allow_c99) && (nst == FUNC || ost == FUNC)) { 3564 const char *nts, *ots; 3565 /* null pointers are already handled in convert() */ 3566 *(nst == FUNC ? &nts : &ots) = "function pointer"; 3567 *(nst == VOID ? &nts : &ots) = "'void *'"; 3568 /* ANSI C forbids conversion of %s to %s */ 3569 warning(303, ots, nts); 3570 } 3571 return; 3572 } 3573 if (nst == FUNC && ost == FUNC) 3574 return; 3575 if (nst == FUNC || ost == FUNC) { 3576 /* converting '%s' to '%s' is questionable */ 3577 warning(229, type_name(otp), type_name(ntp)); 3578 return; 3579 } 3580 3581 if (hflag && alignment_in_bits(nstp) > alignment_in_bits(ostp) && 3582 ost != CHAR && ost != UCHAR && 3583 !is_incomplete(ostp) && 3584 !(nst == UNION && union_contains(nstp, ostp))) { 3585 /* converting '%s' to '%s' increases alignment ... */ 3586 warning(135, type_name(otp), type_name(ntp), 3587 alignment_in_bits(ostp) / CHAR_SIZE, 3588 alignment_in_bits(nstp) / CHAR_SIZE); 3589 } 3590 3591 if (cflag && should_warn_about_pointer_cast(nstp, nst, ostp, ost)) { 3592 /* pointer cast from '%s' to '%s' may be troublesome */ 3593 warning(247, type_name(otp), type_name(ntp)); 3594 } 3595 } 3596 3597 /* 3598 * Insert a conversion operator, which converts the type of the node 3599 * to another given type. 3600 * 3601 * Possible values for 'op': 3602 * CVT a cast-expression 3603 * binary integer promotion for one of the operands, or a usual 3604 * arithmetic conversion 3605 * binary plain or compound assignments to bit-fields 3606 * FARG 'arg' is the number of the argument (used for warnings) 3607 * NOOP several other implicit conversions 3608 * ... 3609 */ 3610 tnode_t * 3611 convert(op_t op, int arg, type_t *tp, tnode_t *tn) 3612 { 3613 tspec_t nt = tp->t_tspec; 3614 tspec_t ot = tn->tn_type->t_tspec; 3615 3616 if (allow_trad && allow_c90 && op == FARG) 3617 check_prototype_conversion(arg, nt, ot, tp, tn); 3618 3619 if (nt == BOOL) { 3620 /* No further checks. */ 3621 3622 } else if (is_integer(nt)) { 3623 if (ot == BOOL) { 3624 /* No further checks. */ 3625 } else if (is_integer(ot)) 3626 convert_integer_from_integer(op, arg, nt, ot, tp, tn); 3627 else if (is_floating(ot)) 3628 convert_integer_from_floating(op, tp, tn); 3629 else if (ot == PTR) 3630 convert_integer_from_pointer(op, nt, tp, tn); 3631 3632 } else if (is_floating(nt)) { 3633 /* No further checks. */ 3634 3635 } else if (nt == PTR) { 3636 if (is_null_pointer(tn)) { 3637 /* a null pointer may be assigned to any pointer. */ 3638 } else if (ot == PTR && op == CVT) 3639 convert_pointer_from_pointer(tp, tn); 3640 } 3641 3642 tnode_t *ntn = expr_alloc_tnode(); 3643 ntn->tn_op = CVT; 3644 ntn->tn_type = tp; 3645 ntn->tn_cast = op == CVT; 3646 ntn->tn_sys |= tn->tn_sys; 3647 ntn->tn_right = NULL; 3648 if (tn->tn_op != CON || nt == VOID) { 3649 ntn->tn_left = tn; 3650 } else { 3651 ntn->tn_op = CON; 3652 convert_constant(op, arg, ntn->tn_type, &ntn->tn_val, 3653 &tn->tn_val); 3654 } 3655 3656 return ntn; 3657 } 3658 3659 static void 3660 convert_constant_floating(op_t op, int arg, tspec_t ot, const type_t *tp, 3661 tspec_t nt, val_t *v, val_t *nv) 3662 { 3663 long double max = 0.0, min = 0.0; 3664 3665 switch (nt) { 3666 case CHAR: 3667 max = TARG_CHAR_MAX; min = TARG_CHAR_MIN; break; 3668 case UCHAR: 3669 max = TARG_UCHAR_MAX; min = 0; break; 3670 case SCHAR: 3671 max = TARG_SCHAR_MAX; min = TARG_SCHAR_MIN; break; 3672 case SHORT: 3673 max = TARG_SHRT_MAX; min = TARG_SHRT_MIN; break; 3674 case USHORT: 3675 max = TARG_USHRT_MAX; min = 0; break; 3676 case ENUM: 3677 case INT: 3678 max = TARG_INT_MAX; min = TARG_INT_MIN; break; 3679 case UINT: 3680 max = TARG_UINT_MAX; min = 0; break; 3681 case LONG: 3682 max = TARG_LONG_MAX; min = TARG_LONG_MIN; break; 3683 case ULONG: 3684 max = TARG_ULONG_MAX; min = 0; break; 3685 case LLONG: 3686 max = LLONG_MAX; min = LLONG_MIN; break; 3687 case ULLONG: 3688 max = ULLONG_MAX; min = 0; break; 3689 case FLOAT: 3690 case FCOMPLEX: 3691 max = FLT_MAX; min = -FLT_MAX; break; 3692 case DOUBLE: 3693 case DCOMPLEX: 3694 max = DBL_MAX; min = -DBL_MAX; break; 3695 case PTR: 3696 /* Already got an error because of float --> ptr */ 3697 case LDOUBLE: 3698 case LCOMPLEX: 3699 /* LINTED 248 */ 3700 max = LDBL_MAX; min = -max; break; 3701 default: 3702 lint_assert(/*CONSTCOND*/false); 3703 } 3704 if (v->u.floating > max || v->u.floating < min) { 3705 lint_assert(nt != LDOUBLE); 3706 if (op == FARG) { 3707 /* conversion of '%s' to '%s' is out of range, ... */ 3708 warning(295, 3709 type_name(gettyp(ot)), type_name(tp), arg); 3710 } else { 3711 /* conversion of '%s' to '%s' is out of range */ 3712 warning(119, type_name(gettyp(ot)), type_name(tp)); 3713 } 3714 v->u.floating = v->u.floating > 0 ? max : min; 3715 } 3716 3717 if (nt == FLOAT || nt == FCOMPLEX) 3718 nv->u.floating = (float)v->u.floating; 3719 else if (nt == DOUBLE || nt == DCOMPLEX) 3720 nv->u.floating = (double)v->u.floating; 3721 else if (nt == LDOUBLE || nt == LCOMPLEX) 3722 nv->u.floating = v->u.floating; 3723 else 3724 nv->u.integer = (int64_t)v->u.floating; 3725 } 3726 3727 static bool 3728 convert_constant_to_floating(tspec_t nt, val_t *nv, 3729 tspec_t ot, const val_t *v) 3730 { 3731 if (nt == FLOAT) { 3732 nv->u.floating = (ot == PTR || is_uinteger(ot)) ? 3733 (float)(uint64_t)v->u.integer : (float)v->u.integer; 3734 } else if (nt == DOUBLE) { 3735 nv->u.floating = (ot == PTR || is_uinteger(ot)) ? 3736 (double)(uint64_t)v->u.integer : (double)v->u.integer; 3737 } else if (nt == LDOUBLE) { 3738 nv->u.floating = (ot == PTR || is_uinteger(ot)) 3739 ? (long double)(uint64_t)v->u.integer 3740 : (long double)v->u.integer; 3741 } else 3742 return false; 3743 return true; 3744 } 3745 3746 /* 3747 * Print a warning if bits which were set are lost due to the conversion. 3748 * This can happen with operator ORASS only. 3749 */ 3750 static void 3751 convert_constant_check_range_bitor(size_t nsz, size_t osz, const val_t *v, 3752 uint64_t xmask, op_t op) 3753 { 3754 if (nsz < osz && (v->u.integer & xmask) != 0) { 3755 /* constant truncated by conversion, op '%s' */ 3756 warning(306, op_name(op)); 3757 } 3758 } 3759 3760 /* 3761 * Print a warning if additional bits are not all 1 3762 * and the most significant bit of the old value is 1, 3763 * or if at least one (but not all) removed bit was 0. 3764 */ 3765 static void 3766 convert_constant_check_range_bitand(size_t nsz, size_t osz, 3767 uint64_t xmask, const val_t *nv, 3768 tspec_t ot, const val_t *v, 3769 const type_t *tp, op_t op) 3770 { 3771 if (nsz > osz && 3772 (nv->u.integer & bit((unsigned int)(osz - 1))) != 0 && 3773 (nv->u.integer & xmask) != xmask) { 3774 /* extra bits set to 0 in conversion of '%s' to '%s', ... */ 3775 warning(309, type_name(gettyp(ot)), 3776 type_name(tp), op_name(op)); 3777 } else if (nsz < osz && 3778 (v->u.integer & xmask) != xmask && 3779 (v->u.integer & xmask) != 0) { 3780 /* constant truncated by conversion, op '%s' */ 3781 warning(306, op_name(op)); 3782 } 3783 } 3784 3785 static void 3786 convert_constant_check_range_signed(op_t op, int arg) 3787 { 3788 if (op == ASSIGN) { 3789 /* assignment of negative constant to unsigned type */ 3790 warning(164); 3791 } else if (op == INIT) { 3792 /* initialization of unsigned with negative constant */ 3793 warning(221); 3794 } else if (op == FARG) { 3795 /* conversion of negative constant to unsigned type, ... */ 3796 warning(296, arg); 3797 } else if (modtab[op].m_comparison) { 3798 /* handled by check_integer_comparison() */ 3799 } else { 3800 /* conversion of negative constant to unsigned type */ 3801 warning(222); 3802 } 3803 } 3804 3805 /* 3806 * Loss of significant bit(s). All truncated bits of unsigned types or all 3807 * truncated bits plus the msb of the target for signed types are considered 3808 * to be significant bits. Loss of significant bits means that at least one 3809 * of the bits was set in an unsigned type or that at least one but not all 3810 * of the bits was set in a signed type. Loss of significant bits means that 3811 * it is not possible, also not with necessary casts, to convert back to the 3812 * original type. An example for a necessary cast is: 3813 * char c; int i; c = 128; 3814 * i = c; ** yields -128 ** 3815 * i = (unsigned char)c; ** yields 128 ** 3816 */ 3817 static void 3818 warn_constant_check_range_truncated(op_t op, int arg, const type_t *tp, 3819 tspec_t ot) 3820 { 3821 if (op == ASSIGN && tp->t_bitfield) 3822 /* precision lost in bit-field assignment */ 3823 warning(166); 3824 else if (op == ASSIGN) 3825 /* constant truncated by assignment */ 3826 warning(165); 3827 else if (op == INIT && tp->t_bitfield) 3828 /* bit-field initializer does not fit */ 3829 warning(180); 3830 else if (op == INIT) 3831 /* initializer does not fit */ 3832 warning(178); 3833 else if (op == CASE) 3834 /* case label affected by conversion */ 3835 warning(196); 3836 else if (op == FARG) 3837 /* conversion of '%s' to '%s' is out of range, arg #%d */ 3838 warning(295, type_name(gettyp(ot)), type_name(tp), arg); 3839 else 3840 /* conversion of '%s' to '%s' is out of range */ 3841 warning(119, type_name(gettyp(ot)), type_name(tp)); 3842 } 3843 3844 static void 3845 warn_constant_check_range_loss(op_t op, int arg, const type_t *tp, 3846 tspec_t ot) 3847 { 3848 if (op == ASSIGN && tp->t_bitfield) 3849 /* precision lost in bit-field assignment */ 3850 warning(166); 3851 else if (op == INIT && tp->t_bitfield) 3852 /* bit-field initializer out of range */ 3853 warning(11); 3854 else if (op == CASE) 3855 /* case label affected by conversion */ 3856 warning(196); 3857 else if (op == FARG) 3858 /* conversion of '%s' to '%s' is out of range, arg #%d */ 3859 warning(295, type_name(gettyp(ot)), type_name(tp), arg); 3860 else 3861 /* conversion of '%s' to '%s' is out of range */ 3862 warning(119, type_name(gettyp(ot)), type_name(tp)); 3863 } 3864 3865 static void 3866 convert_constant_check_range(tspec_t ot, const type_t *tp, tspec_t nt, 3867 op_t op, int arg, const val_t *v, val_t *nv) 3868 { 3869 unsigned int obitsz, nbitsz; 3870 uint64_t xmask, xmsk1; 3871 3872 obitsz = size_in_bits(ot); 3873 nbitsz = tp->t_bitfield ? tp->t_bit_field_width : size_in_bits(nt); 3874 xmask = value_bits(nbitsz) ^ value_bits(obitsz); 3875 xmsk1 = value_bits(nbitsz) ^ value_bits(obitsz - 1); 3876 /* 3877 * For bitwise operations we are not interested in the arithmetic 3878 * value, but in the bits itself. 3879 */ 3880 if (op == ORASS || op == BITOR || op == BITXOR) { 3881 convert_constant_check_range_bitor( 3882 nbitsz, obitsz, v, xmask, op); 3883 } else if (op == ANDASS || op == BITAND) { 3884 convert_constant_check_range_bitand( 3885 nbitsz, obitsz, xmask, nv, ot, v, tp, op); 3886 } else if ((nt != PTR && is_uinteger(nt)) && 3887 (ot != PTR && !is_uinteger(ot)) && 3888 v->u.integer < 0) 3889 convert_constant_check_range_signed(op, arg); 3890 else if (nv->u.integer != v->u.integer && nbitsz <= obitsz && 3891 (v->u.integer & xmask) != 0 && 3892 (is_uinteger(ot) || (v->u.integer & xmsk1) != xmsk1)) 3893 warn_constant_check_range_truncated(op, arg, tp, ot); 3894 else if (nv->u.integer != v->u.integer) 3895 warn_constant_check_range_loss(op, arg, tp, ot); 3896 } 3897 3898 /* 3899 * Converts a typed constant to a constant of another type. 3900 * 3901 * op operator which requires conversion 3902 * arg if op is FARG, # of argument 3903 * tp type to which to convert the constant 3904 * nv new constant 3905 * v old constant 3906 */ 3907 void 3908 convert_constant(op_t op, int arg, const type_t *tp, val_t *nv, val_t *v) 3909 { 3910 /* 3911 * TODO: make 'v' const; the name of this function does not suggest 3912 * that it modifies 'v'. 3913 */ 3914 tspec_t ot = v->v_tspec; 3915 tspec_t nt = nv->v_tspec = tp->t_tspec; 3916 bool range_check = false; 3917 3918 if (nt == BOOL) { /* C99 6.3.1.2 */ 3919 nv->v_unsigned_since_c90 = false; 3920 nv->u.integer = is_nonzero_val(v) ? 1 : 0; 3921 return; 3922 } 3923 3924 if (ot == FLOAT || ot == DOUBLE || ot == LDOUBLE) 3925 convert_constant_floating(op, arg, ot, tp, nt, v, nv); 3926 else if (!convert_constant_to_floating(nt, nv, ot, v)) { 3927 range_check = true; /* Check for lost precision. */ 3928 nv->u.integer = v->u.integer; 3929 } 3930 3931 if (allow_trad && allow_c90 && v->v_unsigned_since_c90 && 3932 (is_floating(nt) || ( 3933 (is_integer(nt) && !is_uinteger(nt) && 3934 portable_rank_cmp(nt, ot) > 0)))) { 3935 /* ANSI C treats constant as unsigned */ 3936 warning(157); 3937 v->v_unsigned_since_c90 = false; 3938 } 3939 3940 if (is_integer(nt)) { 3941 nv->u.integer = convert_integer(nv->u.integer, nt, 3942 tp->t_bitfield ? tp->t_bit_field_width : size_in_bits(nt)); 3943 } 3944 3945 if (range_check && op != CVT) 3946 convert_constant_check_range(ot, tp, nt, op, arg, v, nv); 3947 } 3948 3949 /* 3950 * Create a constant node for sizeof. 3951 */ 3952 tnode_t * 3953 build_sizeof(const type_t *tp) 3954 { 3955 unsigned int size_in_bytes = type_size_in_bits(tp) / CHAR_SIZE; 3956 tnode_t *tn = build_integer_constant(SIZEOF_TSPEC, size_in_bytes); 3957 tn->tn_system_dependent = true; 3958 debug_step("build_sizeof '%s' = %u", type_name(tp), size_in_bytes); 3959 return tn; 3960 } 3961 3962 /* 3963 * Create a constant node for offsetof. 3964 */ 3965 /* ARGSUSED */ /* FIXME: See implementation comments. */ 3966 tnode_t * 3967 build_offsetof(const type_t *tp, const sym_t *sym) 3968 { 3969 3970 if (!is_struct_or_union(tp->t_tspec)) 3971 /* unacceptable operand of '%s' */ 3972 error(111, "offsetof"); 3973 3974 /* FIXME: Don't wrongly use the size of the whole type, use sym. */ 3975 unsigned int offset_in_bytes = type_size_in_bits(tp) / CHAR_SIZE; 3976 tnode_t *tn = build_integer_constant(SIZEOF_TSPEC, offset_in_bytes); 3977 tn->tn_system_dependent = true; 3978 return tn; 3979 } 3980 3981 unsigned int 3982 type_size_in_bits(const type_t *tp) 3983 { 3984 3985 unsigned int elem = 1; 3986 bool flex = false; 3987 lint_assert(tp != NULL); 3988 while (tp->t_tspec == ARRAY) { 3989 flex = true; /* allow c99 flex arrays [] [0] */ 3990 elem *= tp->t_dim; 3991 tp = tp->t_subt; 3992 } 3993 if (elem == 0 && !flex) { 3994 /* cannot take size/alignment of incomplete type */ 3995 error(143); 3996 elem = 1; 3997 } 3998 3999 unsigned int elsz; 4000 switch (tp->t_tspec) { 4001 case VOID: 4002 /* cannot take size/alignment of void */ 4003 error(146); 4004 elsz = 1; 4005 break; 4006 case FUNC: 4007 /* cannot take size/alignment of function type '%s' */ 4008 error(144, type_name(tp)); 4009 elsz = 1; 4010 break; 4011 case STRUCT: 4012 case UNION: 4013 if (is_incomplete(tp)) { 4014 /* cannot take size/alignment of incomplete type */ 4015 error(143); 4016 elsz = 1; 4017 } else { 4018 elsz = tp->t_sou->sou_size_in_bits; 4019 } 4020 break; 4021 case ENUM: 4022 if (is_incomplete(tp)) { 4023 /* cannot take size/alignment of incomplete type */ 4024 warning(143); 4025 } 4026 /* FALLTHROUGH */ 4027 default: 4028 if (tp->t_bitfield) { 4029 /* cannot take size/alignment of bit-field */ 4030 error(145); 4031 } 4032 elsz = size_in_bits(tp->t_tspec); 4033 lint_assert(elsz > 0); 4034 break; 4035 } 4036 4037 return elem * elsz; 4038 } 4039 4040 /* C11 6.5.3.4, GCC */ 4041 tnode_t * 4042 build_alignof(const type_t *tp) 4043 { 4044 if (tp->t_tspec == FUNC) { 4045 /* cannot take size/alignment of function type '%s' */ 4046 error(144, type_name(tp)); 4047 return NULL; 4048 } 4049 if (tp->t_tspec == VOID) { 4050 /* cannot take size/alignment of void */ 4051 error(146); 4052 return NULL; 4053 } 4054 if (is_incomplete(tp)) { 4055 /* cannot take size/alignment of incomplete type */ 4056 error(143); 4057 return NULL; 4058 } 4059 if (tp->t_bitfield) { 4060 /* cannot take size/alignment of bit-field */ 4061 error(145); 4062 return NULL; 4063 } 4064 return build_integer_constant(SIZEOF_TSPEC, 4065 (int64_t)alignment_in_bits(tp) / CHAR_SIZE); 4066 } 4067 4068 static tnode_t * 4069 cast_to_union(tnode_t *otn, type_t *ntp) 4070 { 4071 4072 if (!allow_gcc) { 4073 /* union cast is a GCC extension */ 4074 error(328); 4075 return NULL; 4076 } 4077 4078 for (const sym_t *m = ntp->t_sou->sou_first_member; 4079 m != NULL; m = m->s_next) { 4080 if (types_compatible(m->s_type, otn->tn_type, 4081 false, false, NULL)) { 4082 tnode_t *ntn = expr_alloc_tnode(); 4083 ntn->tn_op = CVT; 4084 ntn->tn_type = ntp; 4085 ntn->tn_cast = true; 4086 ntn->tn_left = otn; 4087 ntn->tn_right = NULL; 4088 return ntn; 4089 } 4090 } 4091 4092 /* type '%s' is not a member of '%s' */ 4093 error(329, type_name(otn->tn_type), type_name(ntp)); 4094 return NULL; 4095 } 4096 4097 /* 4098 * Type casts. 4099 */ 4100 tnode_t * 4101 cast(tnode_t *tn, type_t *tp) 4102 { 4103 4104 if (tn == NULL) 4105 return NULL; 4106 4107 tn = cconv(tn); 4108 4109 lint_assert(tp != NULL); 4110 tspec_t nt = tp->t_tspec; 4111 tspec_t ot = tn->tn_type->t_tspec; 4112 4113 if (nt == VOID) { 4114 /* 4115 * C90 6.3.4, C99 6.5.4p2 and C11 6.5.4p2 allow any type to 4116 * be cast to void. The only other allowed casts are from a 4117 * scalar type to a scalar type. 4118 */ 4119 } else if (nt == UNION) 4120 return cast_to_union(tn, tp); 4121 else if (nt == STRUCT || nt == ARRAY || nt == FUNC) { 4122 /* Casting to a struct is an undocumented GCC extension. */ 4123 if (!(allow_gcc && nt == STRUCT)) 4124 goto invalid_cast; 4125 } else if (is_struct_or_union(ot)) 4126 goto invalid_cast; 4127 else if (ot == VOID) { 4128 /* improper cast of void expression */ 4129 error(148); 4130 return NULL; 4131 } else if (is_integer(nt) && is_scalar(ot)) { 4132 /* ok */ 4133 } else if (is_floating(nt) && is_arithmetic(ot)) { 4134 /* ok */ 4135 } else if (nt == PTR && is_integer(ot)) { 4136 /* ok */ 4137 } else if (nt == PTR && ot == PTR) { 4138 if (!tp->t_subt->t_const && tn->tn_type->t_subt->t_const) { 4139 if (hflag) 4140 /* cast discards 'const' from type '%s' */ 4141 warning(275, type_name(tn->tn_type)); 4142 } 4143 } else 4144 goto invalid_cast; 4145 4146 if (any_query_enabled && types_compatible(tp, tn->tn_type, 4147 false, false, NULL)) { 4148 /* no-op cast from '%s' to '%s' */ 4149 query_message(6, type_name(tn->tn_type), type_name(tp)); 4150 } 4151 4152 tn = convert(CVT, 0, tp, tn); 4153 tn->tn_cast = true; 4154 4155 return tn; 4156 4157 invalid_cast: 4158 /* invalid cast from '%s' to '%s' */ 4159 error(147, type_name(tn->tn_type), type_name(tp)); 4160 return NULL; 4161 } 4162 4163 /* 4164 * Create the node for a function argument. 4165 * All necessary conversions and type checks are done in 4166 * build_function_call because build_function_argument has no 4167 * information about expected argument types. 4168 */ 4169 tnode_t * 4170 build_function_argument(tnode_t *args, tnode_t *arg) 4171 { 4172 /* 4173 * If there was a serious error in the expression for the argument, 4174 * create a dummy argument so the positions of the remaining arguments 4175 * will not change. 4176 */ 4177 if (arg == NULL) 4178 arg = build_integer_constant(INT, 0); 4179 4180 return build_op(PUSH, arg->tn_sys, arg->tn_type, arg, args); 4181 } 4182 4183 /* 4184 * Compare the type of an argument with the corresponding type of a 4185 * prototype parameter. If it is a valid combination, but both types 4186 * are not the same, insert a conversion to convert the argument into 4187 * the type of the parameter. 4188 */ 4189 static tnode_t * 4190 check_prototype_argument( 4191 int n, /* pos of arg */ 4192 type_t *tp, /* expected type (from prototype) */ 4193 tnode_t *tn) /* argument */ 4194 { 4195 tnode_t *ln = xcalloc(1, sizeof(*ln)); 4196 ln->tn_type = expr_unqualified_type(tp); 4197 ln->tn_lvalue = true; 4198 if (typeok(FARG, n, ln, tn)) { 4199 bool dowarn; 4200 if (!types_compatible(tp, tn->tn_type, 4201 true, false, (dowarn = false, &dowarn)) || dowarn) 4202 tn = convert(FARG, n, tp, tn); 4203 } 4204 free(ln); 4205 return tn; 4206 } 4207 4208 /* 4209 * Check types of all function arguments and insert conversions, 4210 * if necessary. 4211 */ 4212 static tnode_t * 4213 check_function_arguments(type_t *ftp, tnode_t *args) 4214 { 4215 /* get # of parameters in the prototype */ 4216 int npar = 0; 4217 for (sym_t *asym = ftp->t_args; asym != NULL; asym = asym->s_next) 4218 npar++; 4219 4220 /* get # of arguments in the function call */ 4221 int narg = 0; 4222 for (tnode_t *arg = args; arg != NULL; arg = arg->tn_right) 4223 narg++; 4224 4225 sym_t *asym = ftp->t_args; 4226 if (ftp->t_proto && npar != narg && !(ftp->t_vararg && npar < narg)) { 4227 /* argument mismatch: %d %s passed, %d expected */ 4228 error(150, narg, narg > 1 ? "arguments" : "argument", npar); 4229 asym = NULL; 4230 } 4231 4232 for (int n = 1; n <= narg; n++) { 4233 4234 /* 4235 * The rightmost argument is at the top of the argument 4236 * subtree. 4237 */ 4238 tnode_t *arg = args; 4239 for (int i = narg; i > n; i--, arg = arg->tn_right) 4240 continue; 4241 4242 /* some things which are always not allowed */ 4243 tspec_t at = arg->tn_left->tn_type->t_tspec; 4244 if (at == VOID) { 4245 /* void expressions may not be arguments, arg #%d */ 4246 error(151, n); 4247 return NULL; 4248 } else if (is_struct_or_union(at) && 4249 is_incomplete(arg->tn_left->tn_type)) { 4250 /* argument cannot have unknown size, arg #%d */ 4251 error(152, n); 4252 return NULL; 4253 } else if (is_integer(at) && 4254 arg->tn_left->tn_type->t_is_enum && 4255 is_incomplete(arg->tn_left->tn_type)) { 4256 /* argument cannot have unknown size, arg #%d */ 4257 warning(152, n); 4258 } 4259 4260 /* class conversions (arg in value context) */ 4261 arg->tn_left = cconv(arg->tn_left); 4262 4263 if (asym != NULL) { 4264 arg->tn_left = check_prototype_argument( 4265 n, asym->s_type, arg->tn_left); 4266 } else 4267 arg->tn_left = promote(NOOP, true, arg->tn_left); 4268 arg->tn_type = arg->tn_left->tn_type; 4269 4270 if (asym != NULL) 4271 asym = asym->s_next; 4272 } 4273 4274 return args; 4275 } 4276 4277 /* 4278 * Create the node for a function call. Also check types of 4279 * function arguments and insert conversions, if necessary. 4280 */ 4281 tnode_t * 4282 build_function_call(tnode_t *func, bool sys, tnode_t *args) 4283 { 4284 4285 if (func == NULL) 4286 return NULL; 4287 4288 op_t fcop = func->tn_op == NAME && func->tn_type->t_tspec == FUNC 4289 ? CALL : ICALL; 4290 4291 check_ctype_function_call(func, args); 4292 4293 /* Turn the function name into a pointer to the function. */ 4294 func = cconv(func); 4295 4296 if (func->tn_type->t_tspec != PTR || 4297 func->tn_type->t_subt->t_tspec != FUNC) { 4298 /* cannot call '%s', must be a function */ 4299 error(149, type_name(func->tn_type)); 4300 return NULL; 4301 } 4302 4303 args = check_function_arguments(func->tn_type->t_subt, args); 4304 4305 return build_op(fcop, sys, func->tn_type->t_subt->t_subt, func, args); 4306 } 4307 4308 /* 4309 * Return the value of an integral constant expression. 4310 * If the expression is not constant or its type is not an integer 4311 * type, an error message is printed. 4312 */ 4313 val_t * 4314 integer_constant(tnode_t *tn, bool required) 4315 { 4316 4317 if (tn != NULL) 4318 tn = cconv(tn); 4319 if (tn != NULL) 4320 tn = promote(NOOP, false, tn); 4321 4322 val_t *v = xcalloc(1, sizeof(*v)); 4323 4324 if (tn == NULL) { 4325 lint_assert(seen_error); 4326 debug_step("constant node is null; returning 1 instead"); 4327 v->v_tspec = INT; 4328 v->u.integer = 1; 4329 return v; 4330 } 4331 4332 v->v_tspec = tn->tn_type->t_tspec; 4333 4334 if (tn->tn_op == CON) { 4335 lint_assert(tn->tn_type->t_tspec == tn->tn_val.v_tspec); 4336 if (is_integer(tn->tn_val.v_tspec)) { 4337 v->v_unsigned_since_c90 = 4338 tn->tn_val.v_unsigned_since_c90; 4339 v->u.integer = tn->tn_val.u.integer; 4340 return v; 4341 } 4342 v->u.integer = (int64_t)tn->tn_val.u.floating; 4343 } else { 4344 v->u.integer = 1; 4345 } 4346 4347 if (required) 4348 /* integral constant expression expected */ 4349 error(55); 4350 else 4351 /* variable array dimension is a C99/GCC extension */ 4352 c99ism(318); 4353 4354 if (!is_integer(v->v_tspec)) 4355 v->v_tspec = INT; 4356 4357 return v; 4358 } 4359 4360 static bool 4361 is_constcond_false(const tnode_t *tn, tspec_t t) 4362 { 4363 return (t == BOOL || t == INT) && 4364 tn->tn_op == CON && tn->tn_val.u.integer == 0; 4365 } 4366 4367 /* 4368 * Perform some tests on expressions which can't be done in build_binary() 4369 * and functions called by build_binary(). These tests must be done here 4370 * because we need some information about the context in which the operations 4371 * are performed. 4372 * After all tests are performed and dofreeblk is true, expr() frees the 4373 * memory which is used for the expression. 4374 */ 4375 void 4376 expr(tnode_t *tn, bool vctx, bool cond, bool dofreeblk, bool is_do_while) 4377 { 4378 4379 if (tn == NULL) { /* in case of errors */ 4380 expr_free_all(); 4381 return; 4382 } 4383 4384 /* expr() is also called in global initializations */ 4385 if (dcs->d_kind != DLK_EXTERN && !is_do_while) 4386 check_statement_reachable(); 4387 4388 check_expr_misc(tn, vctx, cond, !cond, false, false, false); 4389 if (tn->tn_op == ASSIGN && !tn->tn_parenthesized) { 4390 if (hflag && cond) 4391 /* assignment in conditional context */ 4392 warning(159); 4393 } else if (tn->tn_op == CON) { 4394 if (hflag && cond && !suppress_constcond && 4395 !tn->tn_system_dependent && 4396 !(is_do_while && 4397 is_constcond_false(tn, tn->tn_type->t_tspec))) 4398 /* constant in conditional context */ 4399 warning(161); 4400 } 4401 if (!modtab[tn->tn_op].m_has_side_effect) { 4402 /* 4403 * for left operands of COMMA this warning is already 4404 * printed 4405 */ 4406 if (tn->tn_op != COMMA && !vctx && !cond) 4407 check_null_effect(tn); 4408 } 4409 debug_node(tn); 4410 4411 /* free the tree memory */ 4412 if (dofreeblk) 4413 expr_free_all(); 4414 } 4415 4416 /* 4417 * Checks the range of array indices, if possible. 4418 * amper is set if only the address of the element is used. This 4419 * means that the index is allowed to refer to the first element 4420 * after the array. 4421 */ 4422 static void 4423 check_array_index(tnode_t *tn, bool amper) 4424 { 4425 const tnode_t *ln = tn->tn_left; 4426 const tnode_t *rn = tn->tn_right; 4427 4428 /* We can only check constant indices. */ 4429 if (rn->tn_op != CON) 4430 return; 4431 4432 /* Return if the left node does not stem from an array. */ 4433 if (ln->tn_op != ADDR) 4434 return; 4435 if (ln->tn_left->tn_op != STRING && ln->tn_left->tn_op != NAME) 4436 return; 4437 if (ln->tn_left->tn_type->t_tspec != ARRAY) 4438 return; 4439 4440 /* 4441 * For incomplete array types, we can print a warning only if 4442 * the index is negative. 4443 */ 4444 if (is_incomplete(ln->tn_left->tn_type) && rn->tn_val.u.integer >= 0) 4445 return; 4446 4447 /* Get the size of one array element */ 4448 int elsz = length_in_bits(ln->tn_type->t_subt, NULL); 4449 if (elsz == 0) 4450 return; 4451 elsz /= CHAR_SIZE; 4452 4453 /* Change the unit of the index from bytes to element size. */ 4454 int64_t con = is_uinteger(rn->tn_type->t_tspec) 4455 ? (int64_t)((uint64_t)rn->tn_val.u.integer / elsz) 4456 : rn->tn_val.u.integer / elsz; 4457 4458 int dim = ln->tn_left->tn_type->t_dim + (amper ? 1 : 0); 4459 4460 if (!is_uinteger(rn->tn_type->t_tspec) && con < 0) { 4461 /* array subscript cannot be negative: %ld */ 4462 warning(167, (long)con); 4463 } else if (dim > 0 && (uint64_t)con >= (uint64_t)dim) { 4464 /* array subscript cannot be > %d: %ld */ 4465 warning(168, dim - 1, (long)con); 4466 } 4467 } 4468 4469 static void 4470 check_expr_addr(const tnode_t *ln, bool szof, bool fcall) 4471 { 4472 /* XXX: Taking warn_about_unreachable into account here feels wrong. */ 4473 if (ln->tn_op == NAME && (reached || !warn_about_unreachable)) { 4474 if (!szof) 4475 mark_as_set(ln->tn_sym); 4476 mark_as_used(ln->tn_sym, fcall, szof); 4477 } 4478 if (ln->tn_op == INDIR && ln->tn_left->tn_op == PLUS) 4479 /* check the range of array indices */ 4480 check_array_index(ln->tn_left, true); 4481 } 4482 4483 static void 4484 check_expr_load(const tnode_t *ln) 4485 { 4486 if (ln->tn_op == INDIR && ln->tn_left->tn_op == PLUS) 4487 /* check the range of array indices */ 4488 check_array_index(ln->tn_left, false); 4489 } 4490 4491 /* 4492 * If there is an asm statement in one of the compound statements around, 4493 * there may be other side effects, so don't warn. 4494 */ 4495 static bool 4496 is_asm_around(void) 4497 { 4498 for (decl_level *dl = dcs; dl != NULL; dl = dl->d_enclosing) 4499 if (dl->d_asm) 4500 return true; 4501 return false; 4502 } 4503 4504 static void 4505 check_expr_side_effect(const tnode_t *ln, bool szof) 4506 { 4507 4508 /* XXX: Taking warn_about_unreachable into account here feels wrong. */ 4509 if (ln->tn_op == NAME && (reached || !warn_about_unreachable)) { 4510 scl_t sc = ln->tn_sym->s_scl; 4511 if (sc != EXTERN && sc != STATIC && 4512 !ln->tn_sym->s_set && !szof && !is_asm_around()) { 4513 /* '%s' may be used before set */ 4514 warning(158, ln->tn_sym->s_name); 4515 mark_as_set(ln->tn_sym); 4516 } 4517 mark_as_used(ln->tn_sym, false, false); 4518 } 4519 } 4520 4521 static void 4522 check_expr_assign(const tnode_t *ln, bool szof) 4523 { 4524 /* XXX: Taking warn_about_unreachable into account here feels wrong. */ 4525 if (ln->tn_op == NAME && !szof && (reached || !warn_about_unreachable)) { 4526 mark_as_set(ln->tn_sym); 4527 if (ln->tn_sym->s_scl == EXTERN) 4528 outusg(ln->tn_sym); 4529 } 4530 if (ln->tn_op == INDIR && ln->tn_left->tn_op == PLUS) 4531 /* check the range of array indices */ 4532 check_array_index(ln->tn_left, false); 4533 } 4534 4535 static void 4536 check_expr_call(const tnode_t *tn, const tnode_t *ln, 4537 bool szof, bool vctx, bool cond, bool retval_discarded) 4538 { 4539 lint_assert(ln->tn_op == ADDR); 4540 lint_assert(ln->tn_left->tn_op == NAME); 4541 if (!szof && !is_compiler_builtin(ln->tn_left->tn_sym->s_name)) 4542 outcall(tn, vctx || cond, retval_discarded); 4543 } 4544 4545 static bool 4546 check_expr_op(const tnode_t *tn, op_t op, const tnode_t *ln, 4547 bool szof, bool fcall, bool vctx, bool cond, 4548 bool retval_discarded, bool eqwarn) 4549 { 4550 switch (op) { 4551 case ADDR: 4552 check_expr_addr(ln, szof, fcall); 4553 break; 4554 case LOAD: 4555 check_expr_load(ln); 4556 /* FALLTHROUGH */ 4557 case PUSH: 4558 case INCBEF: 4559 case DECBEF: 4560 case INCAFT: 4561 case DECAFT: 4562 case ADDASS: 4563 case SUBASS: 4564 case MULASS: 4565 case DIVASS: 4566 case MODASS: 4567 case ANDASS: 4568 case ORASS: 4569 case XORASS: 4570 case SHLASS: 4571 case SHRASS: 4572 case REAL: 4573 case IMAG: 4574 check_expr_side_effect(ln, szof); 4575 break; 4576 case ASSIGN: 4577 check_expr_assign(ln, szof); 4578 break; 4579 case CALL: 4580 check_expr_call(tn, ln, szof, vctx, cond, retval_discarded); 4581 break; 4582 case EQ: 4583 if (hflag && eqwarn) 4584 /* operator '==' found where '=' was expected */ 4585 warning(160); 4586 break; 4587 case CON: 4588 case NAME: 4589 case STRING: 4590 return false; 4591 default: 4592 break; 4593 } 4594 return true; 4595 } 4596 4597 /* 4598 * vctx ??? 4599 * cond whether the expression is a condition that 4600 * will be compared with 0 4601 * eqwarn whether the operator '==' might be a 4602 * misspelled '=' 4603 * fcall whether the expression is a function call 4604 * retval_discarded whether the return value of a function call 4605 * is discarded; such calls will be analyzed by 4606 * lint2 in messages 4, 8 and 9 4607 * szof whether the expression is part of a sizeof 4608 * expression, which means that its value is 4609 * discarded since only the type is relevant 4610 */ 4611 void 4612 check_expr_misc(const tnode_t *tn, bool vctx, bool cond, 4613 bool eqwarn, bool fcall, bool retval_discarded, bool szof) 4614 { 4615 4616 if (tn == NULL) 4617 return; 4618 4619 tnode_t *ln = tn->tn_left; 4620 tnode_t *rn = tn->tn_right; 4621 op_t op = tn->tn_op; 4622 const mod_t *mp = &modtab[op]; 4623 4624 if (!check_expr_op(tn, op, ln, 4625 szof, fcall, vctx, cond, retval_discarded, eqwarn)) 4626 return; 4627 4628 bool cvctx = mp->m_value_context; 4629 bool ccond = mp->m_compares_with_zero; 4630 bool eq = mp->m_warn_if_operand_eq && 4631 !ln->tn_parenthesized && 4632 rn != NULL && !rn->tn_parenthesized; 4633 4634 /* 4635 * values of operands of ':' are not used if the type of at least 4636 * one of the operands (for gcc compatibility) is void 4637 * XXX test/value context of QUEST should probably be used as 4638 * context for both operands of COLON 4639 */ 4640 if (op == COLON && tn->tn_type->t_tspec == VOID) 4641 cvctx = ccond = false; 4642 bool discard = op == CVT && tn->tn_type->t_tspec == VOID; 4643 check_expr_misc(ln, cvctx, ccond, eq, op == CALL, discard, szof); 4644 4645 switch (op) { 4646 case PUSH: 4647 if (rn != NULL) 4648 check_expr_misc(rn, false, false, eq, false, false, 4649 szof); 4650 break; 4651 case LOGAND: 4652 case LOGOR: 4653 check_expr_misc(rn, false, true, eq, false, false, szof); 4654 break; 4655 case COLON: 4656 check_expr_misc(rn, cvctx, ccond, eq, false, false, szof); 4657 break; 4658 case COMMA: 4659 check_expr_misc(rn, vctx, cond, false, false, false, szof); 4660 break; 4661 default: 4662 if (mp->m_binary) 4663 check_expr_misc(rn, true, false, eq, false, false, 4664 szof); 4665 break; 4666 } 4667 } 4668 4669 /* 4670 * Return whether the expression can be used for static initialization. 4671 * 4672 * Constant initialization expressions must be constant or an address 4673 * of a static object with an optional offset. In the first case, 4674 * the result is returned in *offsp. In the second case, the static 4675 * object is returned in *symp and the offset in *offsp. 4676 * 4677 * The expression can consist of PLUS, MINUS, ADDR, NAME, STRING and 4678 * CON. Type conversions are allowed if they do not change binary 4679 * representation (including width). 4680 * 4681 * C99 6.6 "Constant expressions" 4682 * C99 6.7.8p4 restricts initializers for static storage duration 4683 */ 4684 bool 4685 constant_addr(const tnode_t *tn, const sym_t **symp, ptrdiff_t *offsp) 4686 { 4687 const sym_t *sym; 4688 ptrdiff_t offs1, offs2; 4689 tspec_t t, ot; 4690 4691 switch (tn->tn_op) { 4692 case MINUS: 4693 if (tn->tn_right->tn_op == CVT) 4694 return constant_addr(tn->tn_right, symp, offsp); 4695 else if (tn->tn_right->tn_op != CON) 4696 return false; 4697 /* FALLTHROUGH */ 4698 case PLUS: 4699 offs1 = offs2 = 0; 4700 if (tn->tn_left->tn_op == CON) { 4701 offs1 = (ptrdiff_t)tn->tn_left->tn_val.u.integer; 4702 if (!constant_addr(tn->tn_right, &sym, &offs2)) 4703 return false; 4704 } else if (tn->tn_right->tn_op == CON) { 4705 offs2 = (ptrdiff_t)tn->tn_right->tn_val.u.integer; 4706 if (tn->tn_op == MINUS) 4707 offs2 = -offs2; 4708 if (!constant_addr(tn->tn_left, &sym, &offs1)) 4709 return false; 4710 } else { 4711 return false; 4712 } 4713 *symp = sym; 4714 *offsp = offs1 + offs2; 4715 return true; 4716 case ADDR: 4717 if (tn->tn_left->tn_op == NAME) { 4718 *symp = tn->tn_left->tn_sym; 4719 *offsp = 0; 4720 return true; 4721 } else { 4722 /* 4723 * If this were the front end of a compiler, we 4724 * would return a label instead of 0, at least if 4725 * 'tn->tn_left->tn_op == STRING'. 4726 */ 4727 *symp = NULL; 4728 *offsp = 0; 4729 return true; 4730 } 4731 case CVT: 4732 t = tn->tn_type->t_tspec; 4733 ot = tn->tn_left->tn_type->t_tspec; 4734 if ((!is_integer(t) && t != PTR) || 4735 (!is_integer(ot) && ot != PTR)) { 4736 return false; 4737 } 4738 #if 0 4739 /* 4740 * consider: 4741 * struct foo { 4742 * unsigned char a; 4743 * } f = { 4744 * (unsigned char)(unsigned long) 4745 * (&(((struct foo *)0)->a)) 4746 * }; 4747 * since psize(unsigned long) != psize(unsigned char), 4748 * this fails. 4749 */ 4750 else if (psize(t) != psize(ot)) 4751 return -1; 4752 #endif 4753 return constant_addr(tn->tn_left, symp, offsp); 4754 default: 4755 return false; 4756 } 4757 } 4758 4759 /* Append s2 to s1, then free s2. */ 4760 strg_t * 4761 cat_strings(strg_t *s1, strg_t *s2) 4762 { 4763 4764 if (s1->st_char != s2->st_char) { 4765 /* cannot concatenate wide and regular string literals */ 4766 error(292); 4767 return s1; 4768 } 4769 4770 size_t len1 = s1->st_len; 4771 size_t len2 = s2->st_len; 4772 size_t chsize = s1->st_char ? sizeof(char) : sizeof(wchar_t); 4773 size_t size1 = len1 * chsize; 4774 size_t size2 = (len2 + 1) * chsize; 4775 s1->st_mem = xrealloc(s1->st_mem, size1 + size2); 4776 memcpy((char *)s1->st_mem + size1, s2->st_mem, size2); 4777 free(s2->st_mem); 4778 4779 s1->st_len = len1 + len2; 4780 free(s2); 4781 4782 return s1; 4783 } 4784 4785 4786 typedef struct stmt_expr { 4787 memory_pool se_mem; 4788 sym_t *se_sym; 4789 struct stmt_expr *se_enclosing; 4790 } stmt_expr; 4791 4792 static stmt_expr *stmt_exprs; 4793 4794 void 4795 begin_statement_expr(void) 4796 { 4797 debug_enter(); 4798 4799 stmt_expr *se = xmalloc(sizeof(*se)); 4800 se->se_mem = expr_save_memory(); 4801 se->se_sym = NULL; 4802 se->se_enclosing = stmt_exprs; 4803 stmt_exprs = se; 4804 } 4805 4806 void 4807 do_statement_expr(tnode_t *tn) 4808 { 4809 block_level--; 4810 mem_block_level--; 4811 stmt_exprs->se_sym = tn != NULL 4812 ? mktempsym(block_dup_type(tn->tn_type)) 4813 : NULL; /* after a syntax error */ 4814 mem_block_level++; 4815 block_level++; 4816 /* '({ ... })' is a GCC extension */ 4817 gnuism(320); 4818 } 4819 4820 tnode_t * 4821 end_statement_expr(void) 4822 { 4823 tnode_t *tn; 4824 4825 stmt_expr *se = stmt_exprs; 4826 if (se->se_sym == NULL) { 4827 tn = NULL; /* after a syntax error */ 4828 goto end; 4829 } 4830 4831 tn = build_name(se->se_sym, false); 4832 (void)expr_save_memory(); /* leak */ 4833 expr_restore_memory(se->se_mem); 4834 stmt_exprs = se->se_enclosing; 4835 free(se); 4836 4837 end: 4838 debug_leave(); 4839 return tn; 4840 } 4841
Indexes created Wed Sep 24 05:09:52 GMT 2025