tree.c revision 1.558
1 /* $NetBSD: tree.c,v 1.558 2023/07/09 12:04:08 rillig Exp $ */ 2 3 /* 4 * Copyright (c) 1994, 1995 Jochen Pohl 5 * All Rights Reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. All advertising materials mentioning features or use of this software 16 * must display the following acknowledgement: 17 * This product includes software developed by Jochen Pohl for 18 * The NetBSD Project. 19 * 4. The name of the author may not be used to endorse or promote products 20 * derived from this software without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 23 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 24 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 25 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 26 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 27 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 28 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 29 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 30 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 31 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 32 */ 33 34 #if HAVE_NBTOOL_CONFIG_H 35 #include "nbtool_config.h" 36 #endif 37 38 #include <sys/cdefs.h> 39 #if defined(__RCSID) 40 __RCSID("$NetBSD: tree.c,v 1.558 2023/07/09 12:04:08 rillig Exp $"); 41 #endif 42 43 #include <float.h> 44 #include <limits.h> 45 #include <math.h> 46 #include <signal.h> 47 #include <stdlib.h> 48 #include <string.h> 49 50 #include "lint1.h" 51 52 53 typedef struct integer_constraints { 54 int64_t smin; /* signed minimum */ 55 int64_t smax; /* signed maximum */ 56 uint64_t umin; /* unsigned minimum */ 57 uint64_t umax; /* unsigned maximum */ 58 uint64_t bset; /* bits that are definitely set */ 59 uint64_t bclr; /* bits that are definitely clear */ 60 } integer_constraints; 61 62 63 static uint64_t 64 u64_fill_right(uint64_t x) 65 { 66 x |= x >> 1; 67 x |= x >> 2; 68 x |= x >> 4; 69 x |= x >> 8; 70 x |= x >> 16; 71 x |= x >> 32; 72 return x; 73 } 74 75 static bool 76 str_ends_with(const char *haystack, const char *needle) 77 { 78 size_t hlen = strlen(haystack); 79 size_t nlen = strlen(needle); 80 81 return nlen <= hlen && 82 memcmp(haystack + hlen - nlen, needle, nlen) == 0; 83 } 84 85 static const char * 86 op_name(op_t op) 87 { 88 return modtab[op].m_name; 89 } 90 91 static unsigned 92 width_in_bits(const type_t *tp) 93 { 94 95 lint_assert(is_integer(tp->t_tspec)); 96 return tp->t_bitfield 97 ? tp->t_bit_field_width 98 : size_in_bits(tp->t_tspec); 99 } 100 101 static int 102 portable_rank_cmp(tspec_t t1, tspec_t t2) { 103 const ttab_t *p1 = type_properties(t1), *p2 = type_properties(t2); 104 lint_assert(p1->tt_rank_kind == p2->tt_rank_kind); 105 lint_assert(p1->tt_rank_value > 0); 106 lint_assert(p2->tt_rank_value > 0); 107 return (int)p1->tt_rank_value - (int)p2->tt_rank_value; 108 } 109 110 static bool 111 ic_maybe_signed(const type_t *tp, const integer_constraints *ic) 112 { 113 return !is_uinteger(tp->t_tspec) && ic->bclr >> 63 == 0; 114 } 115 116 static integer_constraints 117 ic_any(const type_t *tp) 118 { 119 integer_constraints c; 120 121 uint64_t vbits = value_bits(width_in_bits(tp)); 122 if (is_uinteger(tp->t_tspec)) { 123 c.smin = INT64_MIN; 124 c.smax = INT64_MAX; 125 c.umin = 0; 126 c.umax = vbits; 127 c.bset = 0; 128 c.bclr = ~c.umax; 129 } else { 130 c.smin = (int64_t)-1 - (int64_t)(vbits >> 1); 131 c.smax = (int64_t)(vbits >> 1); 132 c.umin = 0; 133 c.umax = UINT64_MAX; 134 c.bset = 0; 135 c.bclr = 0; 136 } 137 return c; 138 } 139 140 static integer_constraints 141 ic_con(const type_t *tp, const val_t *v) 142 { 143 integer_constraints c; 144 145 lint_assert(is_integer(tp->t_tspec)); 146 int64_t si = v->u.integer; 147 uint64_t ui = (uint64_t)si; 148 c.smin = si; 149 c.smax = si; 150 c.umin = ui; 151 c.umax = ui; 152 c.bset = ui; 153 c.bclr = ~ui; 154 return c; 155 } 156 157 static integer_constraints 158 ic_cvt(const type_t *ntp, const type_t *otp, integer_constraints a) 159 { 160 unsigned nw = width_in_bits(ntp); 161 unsigned ow = width_in_bits(otp); 162 bool nu = is_uinteger(ntp->t_tspec); 163 bool ou = is_uinteger(otp->t_tspec); 164 165 if (nw >= ow && nu == ou) 166 return a; 167 if (nw > ow && ou) 168 return a; 169 return ic_any(ntp); 170 } 171 172 static integer_constraints 173 ic_bitand(integer_constraints a, integer_constraints b) 174 { 175 integer_constraints c; 176 177 c.smin = INT64_MIN; 178 c.smax = INT64_MAX; 179 c.umin = 0; 180 c.umax = UINT64_MAX; 181 c.bset = a.bset & b.bset; 182 c.bclr = a.bclr | b.bclr; 183 return c; 184 } 185 186 static integer_constraints 187 ic_bitor(integer_constraints a, integer_constraints b) 188 { 189 integer_constraints c; 190 191 c.smin = INT64_MIN; 192 c.smax = INT64_MAX; 193 c.umin = 0; 194 c.umax = UINT64_MAX; 195 c.bset = a.bset | b.bset; 196 c.bclr = a.bclr & b.bclr; 197 return c; 198 } 199 200 static integer_constraints 201 ic_mod(const type_t *tp, integer_constraints a, integer_constraints b) 202 { 203 integer_constraints c; 204 205 if (ic_maybe_signed(tp, &a) || ic_maybe_signed(tp, &b)) 206 return ic_any(tp); 207 208 c.smin = INT64_MIN; 209 c.smax = INT64_MAX; 210 c.umin = 0; 211 c.umax = b.umax - 1; 212 c.bset = 0; 213 c.bclr = ~u64_fill_right(c.umax); 214 return c; 215 } 216 217 static integer_constraints 218 ic_shl(const type_t *tp, integer_constraints a, integer_constraints b) 219 { 220 integer_constraints c; 221 unsigned int amount; 222 223 if (ic_maybe_signed(tp, &a)) 224 return ic_any(tp); 225 226 if (b.smin == b.smax && b.smin >= 0 && b.smin < 64) 227 amount = (unsigned int)b.smin; 228 else if (b.umin == b.umax && b.umin < 64) 229 amount = (unsigned int)b.umin; 230 else 231 return ic_any(tp); 232 233 c.smin = INT64_MIN; 234 c.smax = INT64_MAX; 235 c.umin = 0; 236 c.umax = UINT64_MAX; 237 c.bset = a.bset << amount; 238 c.bclr = a.bclr << amount | (((uint64_t)1 << amount) - 1); 239 return c; 240 } 241 242 static integer_constraints 243 ic_shr(const type_t *tp, integer_constraints a, integer_constraints b) 244 { 245 integer_constraints c; 246 unsigned int amount; 247 248 if (ic_maybe_signed(tp, &a)) 249 return ic_any(tp); 250 251 if (b.smin == b.smax && b.smin >= 0 && b.smin < 64) 252 amount = (unsigned int)b.smin; 253 else if (b.umin == b.umax && b.umin < 64) 254 amount = (unsigned int)b.umin; 255 else 256 return ic_any(tp); 257 258 c.smin = INT64_MIN; 259 c.smax = INT64_MAX; 260 c.umin = 0; 261 c.umax = UINT64_MAX; 262 c.bset = a.bset >> amount; 263 c.bclr = a.bclr >> amount | ~(~(uint64_t)0 >> amount); 264 return c; 265 } 266 267 static integer_constraints 268 ic_cond(integer_constraints a, integer_constraints b) 269 { 270 integer_constraints c; 271 272 c.smin = a.smin < b.smin ? a.smin : b.smin; 273 c.smax = a.smax > b.smax ? a.smax : b.smax; 274 c.umin = a.umin < b.umin ? a.umin : b.umin; 275 c.umax = a.umax > b.umax ? a.umax : b.umax; 276 c.bset = a.bset | b.bset; 277 c.bclr = a.bclr & b.bclr; 278 return c; 279 } 280 281 static integer_constraints 282 ic_expr(const tnode_t *tn) 283 { 284 integer_constraints lc, rc; 285 286 lint_assert(is_integer(tn->tn_type->t_tspec)); 287 288 switch (tn->tn_op) { 289 case CON: 290 return ic_con(tn->tn_type, &tn->tn_val); 291 case CVT: 292 if (!is_integer(tn->tn_left->tn_type->t_tspec)) 293 return ic_any(tn->tn_type); 294 lc = ic_expr(tn->tn_left); 295 return ic_cvt(tn->tn_type, tn->tn_left->tn_type, lc); 296 case MOD: 297 lc = ic_expr(before_conversion(tn->tn_left)); 298 rc = ic_expr(before_conversion(tn->tn_right)); 299 return ic_mod(tn->tn_type, lc, rc); 300 case SHL: 301 lc = ic_expr(tn->tn_left); 302 rc = ic_expr(tn->tn_right); 303 return ic_shl(tn->tn_type, lc, rc); 304 case SHR: 305 lc = ic_expr(tn->tn_left); 306 rc = ic_expr(tn->tn_right); 307 return ic_shr(tn->tn_type, lc, rc); 308 case BITAND: 309 lc = ic_expr(tn->tn_left); 310 rc = ic_expr(tn->tn_right); 311 return ic_bitand(lc, rc); 312 case BITOR: 313 lc = ic_expr(tn->tn_left); 314 rc = ic_expr(tn->tn_right); 315 return ic_bitor(lc, rc); 316 case QUEST: 317 lc = ic_expr(tn->tn_right->tn_left); 318 rc = ic_expr(tn->tn_right->tn_right); 319 return ic_cond(lc, rc); 320 default: 321 return ic_any(tn->tn_type); 322 } 323 } 324 325 /* Build 'pointer to tp', 'array of tp' or 'function returning tp'. */ 326 type_t * 327 block_derive_type(type_t *tp, tspec_t t) 328 { 329 type_t *tp2; 330 331 tp2 = block_zero_alloc(sizeof(*tp2)); 332 tp2->t_tspec = t; 333 tp2->t_subt = tp; 334 return tp2; 335 } 336 337 /* 338 * Derive 'pointer to tp' or 'function returning tp'. 339 * The memory is freed at the end of the current expression. 340 */ 341 type_t * 342 expr_derive_type(type_t *tp, tspec_t t) 343 { 344 type_t *tp2; 345 346 tp2 = expr_zero_alloc(sizeof(*tp2)); 347 tp2->t_tspec = t; 348 tp2->t_subt = tp; 349 return tp2; 350 } 351 352 /* 353 * Build and initialize a new node. 354 */ 355 static tnode_t * 356 new_tnode(op_t op, bool sys, type_t *type, tnode_t *ln, tnode_t *rn) 357 { 358 359 tnode_t *ntn = expr_alloc_tnode(); 360 ntn->tn_op = op; 361 ntn->tn_type = type; 362 ntn->tn_sys = sys; 363 ntn->tn_left = ln; 364 ntn->tn_right = rn; 365 366 if (op == INDIR || op == FSEL) { 367 lint_assert(ln->tn_type->t_tspec == PTR); 368 tspec_t t = ln->tn_type->t_subt->t_tspec; 369 if (t != FUNC && t != VOID) 370 ntn->tn_lvalue = true; 371 } 372 373 return ntn; 374 } 375 376 /* 377 * Create a node for a constant. 378 */ 379 tnode_t * 380 build_constant(type_t *tp, val_t *v) 381 { 382 383 tnode_t *n = expr_alloc_tnode(); 384 n->tn_op = CON; 385 n->tn_type = tp; 386 n->tn_val = *v; 387 n->tn_val.v_tspec = tp->t_tspec; 388 free(v); 389 return n; 390 } 391 392 static tnode_t * 393 build_integer_constant(tspec_t t, int64_t si) 394 { 395 396 tnode_t *n = expr_alloc_tnode(); 397 n->tn_op = CON; 398 n->tn_type = gettyp(t); 399 n->tn_val.v_tspec = t; 400 n->tn_val.v_unsigned_since_c90 = false; 401 n->tn_val.v_char_constant = false; 402 n->tn_val.u.integer = si; 403 return n; 404 } 405 406 static void 407 fallback_symbol(sym_t *sym) 408 { 409 410 if (Tflag && fallback_symbol_strict_bool(sym)) 411 return; 412 413 if (block_level > 0 && (strcmp(sym->s_name, "__FUNCTION__") == 0 || 414 strcmp(sym->s_name, "__PRETTY_FUNCTION__") == 0)) { 415 /* __FUNCTION__/__PRETTY_FUNCTION__ is a GCC extension */ 416 gnuism(316); 417 sym->s_type = block_derive_type(gettyp(CHAR), PTR); 418 sym->s_type->t_const = true; 419 return; 420 } 421 422 if (block_level > 0 && strcmp(sym->s_name, "__func__") == 0) { 423 if (!allow_c99) 424 /* __func__ is a C99 feature */ 425 warning(317); 426 /* C11 6.4.2.2 */ 427 sym->s_type = block_derive_type(gettyp(CHAR), ARRAY); 428 sym->s_type->t_const = true; 429 sym->s_type->t_dim = (int)strlen(funcsym->s_name) + 1; 430 return; 431 } 432 433 /* '%s' undefined */ 434 error(99, sym->s_name); 435 } 436 437 /* 438 * Functions that are predeclared by GCC or other compilers can be called 439 * with arbitrary arguments. Since lint usually runs after a successful 440 * compilation, it's the compiler's job to catch any errors. 441 */ 442 bool 443 is_compiler_builtin(const char *name) 444 { 445 /* https://gcc.gnu.org/onlinedocs/gcc/C-Extensions.html */ 446 if (allow_gcc) { 447 if (strncmp(name, "__atomic_", 9) == 0 || 448 strncmp(name, "__builtin_", 10) == 0 || 449 strcmp(name, "alloca") == 0 || 450 /* obsolete but still in use, as of 2021 */ 451 strncmp(name, "__sync_", 7) == 0) 452 return true; 453 } 454 455 /* https://software.intel.com/sites/landingpage/IntrinsicsGuide/ */ 456 if (strncmp(name, "_mm_", 4) == 0) 457 return true; 458 459 return false; 460 } 461 462 /* https://gcc.gnu.org/onlinedocs/gcc/Integer-Overflow-Builtins.html */ 463 static bool 464 is_gcc_bool_builtin(const char *name) 465 { 466 return strncmp(name, "__builtin_", 10) == 0 && 467 (str_ends_with(name, "_overflow") || 468 str_ends_with(name, "_overflow_p")); 469 } 470 471 static void 472 build_name_call(sym_t *sym) 473 { 474 475 if (is_compiler_builtin(sym->s_name)) { 476 /* 477 * Do not warn about these, just assume that 478 * they are regular functions compatible with 479 * non-prototype calling conventions. 480 */ 481 if (allow_gcc && is_gcc_bool_builtin(sym->s_name)) 482 sym->s_type = gettyp(BOOL); 483 } else if (allow_c99) { 484 /* function '%s' implicitly declared to return int */ 485 error(215, sym->s_name); 486 } else if (!allow_trad) { 487 /* function '%s' implicitly declared to return int */ 488 warning(215, sym->s_name); 489 } 490 491 /* XXX if !allow_c90, the symbol should be exported to level 0 */ 492 sym->s_type = block_derive_type(sym->s_type, FUNC); 493 } 494 495 /* Create a node for a name (symbol table entry). */ 496 tnode_t * 497 build_name(sym_t *sym, bool is_funcname) 498 { 499 500 if (sym->s_scl == NOSCL && !in_gcc_attribute) { 501 sym->s_scl = EXTERN; 502 sym->s_def = DECL; 503 if (is_funcname) 504 build_name_call(sym); 505 else 506 fallback_symbol(sym); 507 } 508 509 lint_assert(sym->s_kind == FVFT || sym->s_kind == FMEMBER); 510 511 tnode_t *n = expr_alloc_tnode(); 512 n->tn_type = sym->s_type; 513 if (sym->s_scl == BOOL_CONST) { 514 n->tn_op = CON; 515 n->tn_val.v_tspec = BOOL; 516 n->tn_val.v_unsigned_since_c90 = false; 517 n->tn_val.v_char_constant = false; 518 n->tn_val.u.integer = sym->u.s_bool_constant ? 1 : 0; 519 } else if (sym->s_scl == ENUM_CONST) { 520 n->tn_op = CON; 521 n->tn_val.v_tspec = INT; /* ENUM is in n->tn_type */ 522 n->tn_val.v_unsigned_since_c90 = false; 523 n->tn_val.v_char_constant = false; 524 n->tn_val.u.integer = sym->u.s_enum_constant; 525 } else { 526 n->tn_op = NAME; 527 n->tn_sym = sym; 528 if (sym->s_kind == FVFT && sym->s_type->t_tspec != FUNC) 529 n->tn_lvalue = true; 530 } 531 532 return n; 533 } 534 535 tnode_t * 536 build_string(strg_t *strg) 537 { 538 size_t len = strg->st_len; 539 540 type_t *tp = expr_zero_alloc(sizeof(*tp)); 541 tp->t_tspec = ARRAY; 542 tp->t_subt = gettyp(strg->st_char ? CHAR : WCHAR); 543 tp->t_dim = (int)(len + 1); 544 545 tnode_t *n = expr_alloc_tnode(); 546 n->tn_op = STRING; 547 n->tn_type = tp; 548 n->tn_lvalue = true; 549 550 n->tn_string = expr_zero_alloc(sizeof(*n->tn_string)); 551 n->tn_string->st_char = strg->st_char; 552 n->tn_string->st_len = len; 553 554 size_t chsize = strg->st_char ? sizeof(char) : sizeof(wchar_t); 555 size_t size = (len + 1) * chsize; 556 n->tn_string->st_mem = expr_zero_alloc(size); 557 (void)memcpy(n->tn_string->st_mem, strg->st_mem, size); 558 free(strg->st_mem); 559 free(strg); 560 561 return n; 562 } 563 564 tnode_t * 565 build_generic_selection(const tnode_t *expr, 566 struct generic_association *sel) 567 { 568 tnode_t *default_result = NULL; 569 570 for (; sel != NULL; sel = sel->ga_prev) { 571 if (expr != NULL && 572 types_compatible(sel->ga_arg, expr->tn_type, 573 false, false, NULL)) 574 return sel->ga_result; 575 else if (sel->ga_arg == NULL) 576 default_result = sel->ga_result; 577 } 578 return default_result; 579 } 580 581 static bool 582 is_out_of_char_range(const tnode_t *tn) 583 { 584 return tn->tn_op == CON && 585 !tn->tn_val.v_char_constant && 586 !(0 <= tn->tn_val.u.integer && 587 tn->tn_val.u.integer < 1 << (CHAR_SIZE - 1)); 588 } 589 590 static void 591 check_integer_comparison(op_t op, tnode_t *ln, tnode_t *rn) 592 { 593 594 tspec_t lt = ln->tn_type->t_tspec; 595 tspec_t rt = rn->tn_type->t_tspec; 596 597 if (ln->tn_op != CON && rn->tn_op != CON) 598 return; 599 600 if (!is_integer(lt) || !is_integer(rt)) 601 return; 602 603 if (any_query_enabled && !in_system_header) { 604 if (lt == CHAR && rn->tn_op == CON && 605 !rn->tn_val.v_char_constant) { 606 /* comparison '%s' of 'char' with plain integer %d */ 607 query_message(14, 608 op_name(op), (int)rn->tn_val.u.integer); 609 } 610 if (rt == CHAR && ln->tn_op == CON && 611 !ln->tn_val.v_char_constant) { 612 /* comparison '%s' of 'char' with plain integer %d */ 613 query_message(14, 614 op_name(op), (int)ln->tn_val.u.integer); 615 } 616 } 617 618 if (hflag || pflag) { 619 if (lt == CHAR && is_out_of_char_range(rn)) { 620 char buf[128]; 621 (void)snprintf(buf, sizeof(buf), "%s %d", 622 op_name(op), (int)rn->tn_val.u.integer); 623 /* nonportable character comparison '%s' */ 624 warning(230, buf); 625 return; 626 } 627 if (rt == CHAR && is_out_of_char_range(ln)) { 628 char buf[128]; 629 (void)snprintf(buf, sizeof(buf), "%d %s ?", 630 (int)ln->tn_val.u.integer, op_name(op)); 631 /* nonportable character comparison '%s' */ 632 warning(230, buf); 633 return; 634 } 635 } 636 637 if (is_uinteger(lt) && !is_uinteger(rt) && 638 rn->tn_op == CON && rn->tn_val.u.integer <= 0) { 639 if (rn->tn_val.u.integer < 0) { 640 /* operator '%s' compares '%s' with '%s' */ 641 warning(162, op_name(op), 642 type_name(ln->tn_type), "negative constant"); 643 } else if (op == LT || op == GE) { 644 /* operator '%s' compares '%s' with '%s' */ 645 warning(162, op_name(op), type_name(ln->tn_type), "0"); 646 } 647 return; 648 } 649 if (is_uinteger(rt) && !is_uinteger(lt) && 650 ln->tn_op == CON && ln->tn_val.u.integer <= 0) { 651 if (ln->tn_val.u.integer < 0) { 652 /* operator '%s' compares '%s' with '%s' */ 653 warning(162, op_name(op), 654 "negative constant", type_name(rn->tn_type)); 655 } else if (op == GT || op == LE) { 656 /* operator '%s' compares '%s' with '%s' */ 657 warning(162, op_name(op), "0", type_name(rn->tn_type)); 658 } 659 return; 660 } 661 } 662 663 static const tspec_t arith_rank[] = { 664 LDOUBLE, DOUBLE, FLOAT, 665 #ifdef INT128_SIZE 666 UINT128, INT128, 667 #endif 668 ULLONG, LLONG, 669 ULONG, LONG, 670 UINT, INT, 671 }; 672 673 /* Keep unsigned in traditional C */ 674 static tspec_t 675 usual_arithmetic_conversion_trad(tspec_t lt, tspec_t rt) 676 { 677 678 size_t i; 679 for (i = 0; arith_rank[i] != INT; i++) 680 if (lt == arith_rank[i] || rt == arith_rank[i]) 681 break; 682 683 tspec_t t = arith_rank[i]; 684 if (is_uinteger(lt) || is_uinteger(rt)) 685 if (is_integer(t) && !is_uinteger(t)) 686 return unsigned_type(t); 687 return t; 688 } 689 690 static tspec_t 691 usual_arithmetic_conversion_c90(tspec_t lt, tspec_t rt) 692 { 693 694 if (lt == rt) 695 return lt; 696 697 if (lt == LCOMPLEX || rt == LCOMPLEX) 698 return LCOMPLEX; 699 if (lt == DCOMPLEX || rt == DCOMPLEX) 700 return DCOMPLEX; 701 if (lt == FCOMPLEX || rt == FCOMPLEX) 702 return FCOMPLEX; 703 if (lt == LDOUBLE || rt == LDOUBLE) 704 return LDOUBLE; 705 if (lt == DOUBLE || rt == DOUBLE) 706 return DOUBLE; 707 if (lt == FLOAT || rt == FLOAT) 708 return FLOAT; 709 710 /* 711 * If type A has more bits than type B, it should be able to hold all 712 * possible values of type B. 713 */ 714 if (size_in_bits(lt) > size_in_bits(rt)) 715 return lt; 716 if (size_in_bits(lt) < size_in_bits(rt)) 717 return rt; 718 719 size_t i; 720 for (i = 3; arith_rank[i] != INT; i++) 721 if (arith_rank[i] == lt || arith_rank[i] == rt) 722 break; 723 if ((is_uinteger(lt) || is_uinteger(rt)) && 724 !is_uinteger(arith_rank[i])) 725 i--; 726 return arith_rank[i]; 727 } 728 729 static tnode_t * 730 apply_usual_arithmetic_conversions(op_t op, tnode_t *tn, tspec_t t) 731 { 732 type_t *ntp = expr_dup_type(tn->tn_type); 733 ntp->t_tspec = t; 734 if (tn->tn_op != CON) { 735 /* usual arithmetic conversion for '%s' from '%s' to '%s' */ 736 query_message(4, op_name(op), 737 type_name(tn->tn_type), type_name(ntp)); 738 } 739 return convert(op, 0, ntp, tn); 740 } 741 742 /* 743 * Apply the "usual arithmetic conversions" (C99 6.3.1.8), which gives both 744 * operands the same type. 745 */ 746 static void 747 balance(op_t op, tnode_t **lnp, tnode_t **rnp) 748 { 749 750 tspec_t lt = (*lnp)->tn_type->t_tspec; 751 tspec_t rt = (*rnp)->tn_type->t_tspec; 752 if (!is_arithmetic(lt) || !is_arithmetic(rt)) 753 return; 754 755 tspec_t t = allow_c90 756 ? usual_arithmetic_conversion_c90(lt, rt) 757 : usual_arithmetic_conversion_trad(lt, rt); 758 759 if (t != lt) 760 *lnp = apply_usual_arithmetic_conversions(op, *lnp, t); 761 if (t != rt) 762 *rnp = apply_usual_arithmetic_conversions(op, *rnp, t); 763 } 764 765 /* 766 * Create a tree node for the unary & operator 767 */ 768 static tnode_t * 769 build_address(bool sys, tnode_t *tn, bool noign) 770 { 771 tspec_t t; 772 773 if (!noign && ((t = tn->tn_type->t_tspec) == ARRAY || t == FUNC)) { 774 if (!allow_c90) 775 /* '&' before array or function: ignored */ 776 warning(127); 777 return tn; 778 } 779 780 /* eliminate &* */ 781 if (tn->tn_op == INDIR && 782 tn->tn_left->tn_type->t_tspec == PTR && 783 tn->tn_left->tn_type->t_subt == tn->tn_type) { 784 return tn->tn_left; 785 } 786 787 return new_tnode(ADDR, sys, expr_derive_type(tn->tn_type, PTR), 788 tn, NULL); 789 } 790 791 /* 792 * XXX 793 * Note: There appear to be a number of bugs in detecting overflow in 794 * this function. An audit and a set of proper regression tests are needed. 795 * --Perry Metzger, Nov. 16, 2001 796 */ 797 /* 798 * Do only as much as necessary to compute constant expressions. 799 * Called only if the operator allows folding and all operands are constants. 800 */ 801 static tnode_t * 802 fold(tnode_t *tn) 803 { 804 805 val_t *v = xcalloc(1, sizeof(*v)); 806 v->v_tspec = tn->tn_type->t_tspec; 807 808 tspec_t t = tn->tn_left->tn_type->t_tspec; 809 bool utyp = !is_integer(t) || is_uinteger(t); 810 int64_t sl = tn->tn_left->tn_val.u.integer, sr = 0; 811 uint64_t ul = sl, ur = 0; 812 if (is_binary(tn)) 813 ur = sr = tn->tn_right->tn_val.u.integer; 814 815 int64_t mask = (int64_t)value_bits(size_in_bits(t)); 816 bool ovfl = false; 817 818 int64_t si; 819 switch (tn->tn_op) { 820 case UPLUS: 821 si = sl; 822 break; 823 case UMINUS: 824 si = sl == INT64_MIN ? sl : -sl; 825 if (sl != 0 && msb(si, t) == msb(sl, t)) 826 ovfl = true; 827 break; 828 case COMPL: 829 si = ~sl; 830 break; 831 case MULT: 832 if (utyp) { 833 si = (int64_t)(ul * ur); 834 if (si != (si & mask)) 835 ovfl = true; 836 else if ((ul != 0) && ((si / ul) != ur)) 837 ovfl = true; 838 } else { 839 si = sl * sr; 840 if (msb(si, t) != (msb(sl, t) ^ msb(sr, t))) 841 ovfl = true; 842 } 843 break; 844 case DIV: 845 if (sr == 0) { 846 /* division by 0 */ 847 error(139); 848 si = utyp ? -1 : INT64_MAX; 849 } else { 850 si = utyp ? (int64_t)(ul / ur) : sl / sr; 851 } 852 break; 853 case MOD: 854 if (sr == 0) { 855 /* modulus by 0 */ 856 error(140); 857 si = 0; 858 } else { 859 si = utyp ? (int64_t)(ul % ur) : sl % sr; 860 } 861 break; 862 case PLUS: 863 si = utyp ? (int64_t)(ul + ur) : sl + sr; 864 if (msb(sl, t) && msb(sr, t) && !msb(si, t)) 865 ovfl = true; 866 if (!utyp && !msb(sl, t) && !msb(sr, t) && msb(si, t)) 867 ovfl = true; 868 break; 869 case MINUS: 870 si = utyp ? (int64_t)(ul - ur) : sl - sr; 871 if (!utyp && msb(sl, t) && !msb(sr, t) && !msb(si, t)) 872 ovfl = true; 873 if (!msb(sl, t) && msb(sr, t) && msb(si, t)) 874 ovfl = true; 875 break; 876 case SHL: 877 /* TODO: warn about out-of-bounds 'sr'. */ 878 /* TODO: warn about overflow in signed '<<'. */ 879 si = utyp ? (int64_t)(ul << (sr & 63)) : sl << (sr & 63); 880 break; 881 case SHR: 882 /* 883 * The sign must be explicitly extended because 884 * shifts of signed values are implementation dependent. 885 */ 886 /* TODO: warn about out-of-bounds 'sr'. */ 887 si = (int64_t)(ul >> (sr & 63)); 888 si = convert_integer(si, t, size_in_bits(t) - (int)sr); 889 break; 890 case LT: 891 si = (utyp ? ul < ur : sl < sr) ? 1 : 0; 892 break; 893 case LE: 894 si = (utyp ? ul <= ur : sl <= sr) ? 1 : 0; 895 break; 896 case GE: 897 si = (utyp ? ul >= ur : sl >= sr) ? 1 : 0; 898 break; 899 case GT: 900 si = (utyp ? ul > ur : sl > sr) ? 1 : 0; 901 break; 902 case EQ: 903 si = (utyp ? ul == ur : sl == sr) ? 1 : 0; 904 break; 905 case NE: 906 si = (utyp ? ul != ur : sl != sr) ? 1 : 0; 907 break; 908 case BITAND: 909 si = utyp ? (int64_t)(ul & ur) : sl & sr; 910 break; 911 case BITXOR: 912 si = utyp ? (int64_t)(ul ^ ur) : sl ^ sr; 913 break; 914 case BITOR: 915 si = utyp ? (int64_t)(ul | ur) : sl | sr; 916 break; 917 default: 918 lint_assert(/*CONSTCOND*/false); 919 } 920 921 /* XXX: The overflow check does not work for 64-bit integers. */ 922 if (ovfl || 923 ((uint64_t)(si | mask) != ~(uint64_t)0 && (si & ~mask) != 0)) { 924 if (hflag) 925 /* operator '%s' produces integer overflow */ 926 warning(141, op_name(tn->tn_op)); 927 } 928 929 v->u.integer = convert_integer(si, t, 0); 930 931 tnode_t *cn = build_constant(tn->tn_type, v); 932 if (tn->tn_left->tn_system_dependent) 933 cn->tn_system_dependent = true; 934 if (is_binary(tn) && tn->tn_right->tn_system_dependent) 935 cn->tn_system_dependent = true; 936 937 return cn; 938 } 939 940 /* 941 * Create a new node for one of the operators POINT and ARROW. 942 */ 943 static tnode_t * 944 build_struct_access(op_t op, bool sys, tnode_t *ln, tnode_t *rn) 945 { 946 947 lint_assert(rn->tn_op == NAME); 948 lint_assert(is_member(rn->tn_sym)); 949 950 /* 951 * Remember if the left operand is an lvalue (structure members 952 * are lvalues if and only if the structure itself is an lvalue). 953 */ 954 bool nolval = op == POINT && !ln->tn_lvalue; 955 956 if (op == POINT) { 957 ln = build_address(sys, ln, true); 958 } else if (ln->tn_type->t_tspec != PTR) { 959 lint_assert(!allow_c90); 960 lint_assert(is_integer(ln->tn_type->t_tspec)); 961 ln = convert(NOOP, 0, expr_derive_type(gettyp(VOID), PTR), ln); 962 } 963 964 tnode_t *ctn = build_integer_constant(PTRDIFF_TSPEC, 965 rn->tn_sym->u.s_member.sm_offset_in_bits / CHAR_SIZE); 966 967 type_t *ptr_tp = expr_derive_type(rn->tn_type, PTR); 968 tnode_t *ntn = new_tnode(PLUS, sys, ptr_tp, ln, ctn); 969 if (ln->tn_op == CON) 970 ntn = fold(ntn); 971 972 if (rn->tn_type->t_bitfield) { 973 ntn = new_tnode(FSEL, sys, ntn->tn_type->t_subt, ntn, NULL); 974 } else { 975 ntn = new_tnode(INDIR, sys, ntn->tn_type->t_subt, ntn, NULL); 976 } 977 978 if (nolval) 979 ntn->tn_lvalue = false; 980 981 return ntn; 982 } 983 984 /* 985 * Get the size in bytes of type tp->t_subt, as a constant expression of type 986 * ptrdiff_t as seen from the target platform. 987 */ 988 static tnode_t * 989 subt_size_in_bytes(type_t *tp) 990 { 991 992 lint_assert(tp->t_tspec == PTR); 993 tp = tp->t_subt; 994 995 int elem = 1; 996 while (tp->t_tspec == ARRAY) { 997 elem *= tp->t_dim; 998 tp = tp->t_subt; 999 } 1000 1001 int elsz_in_bits = 0; 1002 switch (tp->t_tspec) { 1003 case FUNC: 1004 /* pointer to function is not allowed here */ 1005 error(110); 1006 break; 1007 case VOID: 1008 /* cannot do pointer arithmetic on operand of unknown size */ 1009 gnuism(136); 1010 break; 1011 case STRUCT: 1012 case UNION: 1013 if ((elsz_in_bits = (int)tp->t_sou->sou_size_in_bits) == 0) 1014 /* cannot do pointer arithmetic on operand of ... */ 1015 error(136); 1016 break; 1017 case ENUM: 1018 if (is_incomplete(tp)) { 1019 /* cannot do pointer arithmetic on operand of ... */ 1020 warning(136); 1021 } 1022 /* FALLTHROUGH */ 1023 default: 1024 if ((elsz_in_bits = size_in_bits(tp->t_tspec)) == 0) { 1025 /* cannot do pointer arithmetic on operand of ... */ 1026 error(136); 1027 } else { 1028 lint_assert(elsz_in_bits != -1); 1029 } 1030 break; 1031 } 1032 1033 if (elem == 0 && elsz_in_bits != 0) { 1034 /* cannot do pointer arithmetic on operand of unknown size */ 1035 error(136); 1036 } 1037 1038 if (elsz_in_bits == 0) 1039 elsz_in_bits = CHAR_SIZE; 1040 1041 return build_integer_constant(PTRDIFF_TSPEC, 1042 (int64_t)(elem * elsz_in_bits / CHAR_SIZE)); 1043 } 1044 1045 /* 1046 * Create a node for INCAFT, INCBEF, DECAFT and DECBEF. 1047 */ 1048 static tnode_t * 1049 build_prepost_incdec(op_t op, bool sys, tnode_t *ln) 1050 { 1051 1052 lint_assert(ln != NULL); 1053 tnode_t *cn = ln->tn_type->t_tspec == PTR 1054 ? subt_size_in_bytes(ln->tn_type) 1055 : build_integer_constant(INT, 1); 1056 return new_tnode(op, sys, ln->tn_type, ln, cn); 1057 } 1058 1059 static void 1060 check_enum_array_index(const tnode_t *ln, const tnode_t *rn) 1061 { 1062 1063 if (ln->tn_op != ADDR || ln->tn_left->tn_op != NAME) 1064 return; 1065 1066 const type_t *ltp = ln->tn_left->tn_type; 1067 if (ltp->t_tspec != ARRAY || ltp->t_incomplete_array) 1068 return; 1069 1070 if (rn->tn_op != CVT || !rn->tn_type->t_is_enum) 1071 return; 1072 if (rn->tn_left->tn_op != LOAD) 1073 return; 1074 1075 const type_t *rtp = rn->tn_left->tn_type; 1076 const sym_t *ec = rtp->t_enum->en_first_enumerator; 1077 const sym_t *max_ec = ec; 1078 lint_assert(ec != NULL); 1079 for (ec = ec->s_next; ec != NULL; ec = ec->s_next) 1080 if (ec->u.s_enum_constant > max_ec->u.s_enum_constant) 1081 max_ec = ec; 1082 1083 int64_t max_enum_value = max_ec->u.s_enum_constant; 1084 lint_assert(INT_MIN <= max_enum_value && max_enum_value <= INT_MAX); 1085 1086 int max_array_index = ltp->t_dim - 1; 1087 if (max_enum_value == max_array_index) 1088 return; 1089 1090 /* 1091 * If the name of the largest enum constant contains 'MAX' or 'NUM', 1092 * that constant is typically not part of the allowed enum values but 1093 * a marker for the number of actual enum values. 1094 */ 1095 if (max_enum_value == max_array_index + 1 && 1096 (strstr(max_ec->s_name, "MAX") != NULL || 1097 strstr(max_ec->s_name, "max") != NULL || 1098 strstr(max_ec->s_name, "NUM") != NULL || 1099 strstr(max_ec->s_name, "num") != NULL)) 1100 return; 1101 1102 /* maximum value %d of '%s' does not match maximum array index %d */ 1103 warning(348, (int)max_enum_value, type_name(rtp), max_array_index); 1104 print_previous_declaration(max_ec); 1105 } 1106 1107 /* 1108 * Create a node for operators PLUS and MINUS. 1109 */ 1110 static tnode_t * 1111 build_plus_minus(op_t op, bool sys, tnode_t *ln, tnode_t *rn) 1112 { 1113 1114 /* If pointer and integer, move the pointer to the left. */ 1115 if (rn->tn_type->t_tspec == PTR && is_integer(ln->tn_type->t_tspec)) { 1116 tnode_t *tmp = ln; 1117 ln = rn; 1118 rn = tmp; 1119 /* pointer addition has integer on the left-hand side */ 1120 query_message(5); 1121 } 1122 1123 /* pointer +- integer */ 1124 if (ln->tn_type->t_tspec == PTR && rn->tn_type->t_tspec != PTR) { 1125 lint_assert(is_integer(rn->tn_type->t_tspec)); 1126 1127 check_ctype_macro_invocation(ln, rn); 1128 check_enum_array_index(ln, rn); 1129 1130 tnode_t *elsz = subt_size_in_bytes(ln->tn_type); 1131 if (rn->tn_type->t_tspec != elsz->tn_type->t_tspec) 1132 rn = convert(NOOP, 0, elsz->tn_type, rn); 1133 1134 tnode_t *prod = new_tnode(MULT, sys, rn->tn_type, rn, elsz); 1135 if (rn->tn_op == CON) 1136 prod = fold(prod); 1137 1138 return new_tnode(op, sys, ln->tn_type, ln, prod); 1139 } 1140 1141 /* pointer - pointer */ 1142 if (rn->tn_type->t_tspec == PTR) { 1143 lint_assert(ln->tn_type->t_tspec == PTR); 1144 lint_assert(op == MINUS); 1145 1146 type_t *ptrdiff = gettyp(PTRDIFF_TSPEC); 1147 tnode_t *raw_diff = new_tnode(op, sys, ptrdiff, ln, rn); 1148 if (ln->tn_op == CON && rn->tn_op == CON) 1149 raw_diff = fold(raw_diff); 1150 1151 tnode_t *elsz = subt_size_in_bytes(ln->tn_type); 1152 balance(NOOP, &raw_diff, &elsz); 1153 1154 return new_tnode(DIV, sys, ptrdiff, raw_diff, elsz); 1155 } 1156 1157 return new_tnode(op, sys, ln->tn_type, ln, rn); 1158 } 1159 1160 /* 1161 * Create a node for operators SHL and SHR. 1162 */ 1163 static tnode_t * 1164 build_bit_shift(op_t op, bool sys, tnode_t *ln, tnode_t *rn) 1165 { 1166 1167 if (!allow_c90 && rn->tn_type->t_tspec != INT) 1168 rn = convert(NOOP, 0, gettyp(INT), rn); 1169 return new_tnode(op, sys, ln->tn_type, ln, rn); 1170 } 1171 1172 static bool 1173 is_null_pointer(const tnode_t *tn) 1174 { 1175 tspec_t t = tn->tn_type->t_tspec; 1176 1177 return ((t == PTR && tn->tn_type->t_subt->t_tspec == VOID) || 1178 is_integer(t)) 1179 && (tn->tn_op == CON && tn->tn_val.u.integer == 0); 1180 } 1181 1182 /* Return a type based on tp1, with added qualifiers from tp2. */ 1183 static type_t * 1184 merge_qualifiers(type_t *tp1, const type_t *tp2) 1185 { 1186 1187 lint_assert(tp1->t_tspec == PTR); 1188 lint_assert(tp2->t_tspec == PTR); 1189 1190 bool c1 = tp1->t_subt->t_const; 1191 bool c2 = tp2->t_subt->t_const; 1192 bool v1 = tp1->t_subt->t_volatile; 1193 bool v2 = tp2->t_subt->t_volatile; 1194 1195 if (c1 == (c1 | c2) && v1 == (v1 | v2)) 1196 return tp1; 1197 1198 type_t *nstp = expr_dup_type(tp1->t_subt); 1199 nstp->t_const |= c2; 1200 nstp->t_volatile |= v2; 1201 1202 type_t *ntp = expr_dup_type(tp1); 1203 ntp->t_subt = nstp; 1204 return ntp; 1205 } 1206 1207 /* See C99 6.5.15 "Conditional operator". */ 1208 static tnode_t * 1209 build_colon(bool sys, tnode_t *ln, tnode_t *rn) 1210 { 1211 1212 tspec_t lt = ln->tn_type->t_tspec; 1213 tspec_t rt = rn->tn_type->t_tspec; 1214 1215 type_t *tp; 1216 if (is_arithmetic(lt) && is_arithmetic(rt)) { 1217 /* The operands were already balanced in build_binary. */ 1218 tp = ln->tn_type; 1219 } else if (lt == BOOL && rt == BOOL) { 1220 tp = ln->tn_type; 1221 } else if (lt == VOID || rt == VOID) { 1222 tp = gettyp(VOID); 1223 } else if (is_struct_or_union(lt)) { 1224 /* Both types must be identical. */ 1225 lint_assert(is_struct_or_union(rt)); 1226 lint_assert(ln->tn_type->t_sou == rn->tn_type->t_sou); 1227 if (is_incomplete(ln->tn_type)) { 1228 /* unknown operand size, op '%s' */ 1229 error(138, op_name(COLON)); 1230 return NULL; 1231 } 1232 tp = ln->tn_type; 1233 } else if (lt == PTR && is_integer(rt)) { 1234 if (rt != PTRDIFF_TSPEC) 1235 rn = convert(NOOP, 0, gettyp(PTRDIFF_TSPEC), rn); 1236 tp = ln->tn_type; 1237 } else if (rt == PTR && is_integer(lt)) { 1238 if (lt != PTRDIFF_TSPEC) 1239 ln = convert(NOOP, 0, gettyp(PTRDIFF_TSPEC), ln); 1240 tp = rn->tn_type; 1241 } else if (lt == PTR && is_null_pointer(rn)) { 1242 tp = merge_qualifiers(ln->tn_type, rn->tn_type); 1243 } else if (rt == PTR && is_null_pointer(ln)) { 1244 tp = merge_qualifiers(rn->tn_type, ln->tn_type); 1245 } else if (lt == PTR && ln->tn_type->t_subt->t_tspec == VOID) { 1246 tp = merge_qualifiers(ln->tn_type, rn->tn_type); 1247 } else if (rt == PTR && rn->tn_type->t_subt->t_tspec == VOID) { 1248 tp = merge_qualifiers(rn->tn_type, ln->tn_type); 1249 } else { 1250 /* 1251 * XXX For now we simply take the left type. This is 1252 * probably wrong, if one type contains a function prototype 1253 * and the other one, at the same place, only an old-style 1254 * declaration. 1255 */ 1256 tp = merge_qualifiers(ln->tn_type, rn->tn_type); 1257 } 1258 1259 return new_tnode(COLON, sys, tp, ln, rn); 1260 } 1261 1262 /* TODO: check for varargs */ 1263 static bool 1264 is_cast_redundant(const tnode_t *tn) 1265 { 1266 const type_t *ntp = tn->tn_type, *otp = tn->tn_left->tn_type; 1267 tspec_t nt = ntp->t_tspec, ot = otp->t_tspec; 1268 1269 if (nt == BOOL || ot == BOOL) 1270 return nt == BOOL && ot == BOOL; 1271 1272 if (is_integer(nt) && is_integer(ot)) { 1273 unsigned int nw = width_in_bits(ntp), ow = width_in_bits(otp); 1274 if (is_uinteger(nt) == is_uinteger(ot)) 1275 return nw >= ow; 1276 return is_uinteger(ot) && nw > ow; 1277 } 1278 1279 if (is_complex(nt) || is_complex(ot)) 1280 return is_complex(nt) && is_complex(ot) && 1281 size_in_bits(nt) >= size_in_bits(ot); 1282 1283 if (is_floating(nt) && is_floating(ot)) 1284 return size_in_bits(nt) >= size_in_bits(ot); 1285 1286 if (nt == PTR && ot == PTR) { 1287 if (!ntp->t_subt->t_const && otp->t_subt->t_const) 1288 return false; 1289 if (!ntp->t_subt->t_volatile && otp->t_subt->t_volatile) 1290 return false; 1291 1292 if (ntp->t_subt->t_tspec == VOID || 1293 otp->t_subt->t_tspec == VOID || 1294 types_compatible(ntp->t_subt, otp->t_subt, 1295 false, false, NULL)) 1296 return true; 1297 } 1298 1299 return false; 1300 } 1301 1302 static bool 1303 is_assignment(op_t op) 1304 { 1305 1306 return op == ASSIGN || 1307 op == MULASS || 1308 op == DIVASS || 1309 op == MODASS || 1310 op == ADDASS || 1311 op == SUBASS || 1312 op == SHLASS || 1313 op == SHRASS || 1314 op == ANDASS || 1315 op == XORASS || 1316 op == ORASS || 1317 op == RETURN || 1318 op == INIT; 1319 } 1320 1321 /* Create a node for an assignment operator (both '=' and 'op='). */ 1322 static tnode_t * 1323 build_assignment(op_t op, bool sys, tnode_t *ln, tnode_t *rn) 1324 { 1325 1326 tspec_t lt = ln->tn_type->t_tspec; 1327 tspec_t rt = rn->tn_type->t_tspec; 1328 1329 if (any_query_enabled && is_assignment(rn->tn_op)) { 1330 /* chained assignment with '%s' and '%s' */ 1331 query_message(10, op_name(op), op_name(rn->tn_op)); 1332 } 1333 1334 if ((op == ADDASS || op == SUBASS) && lt == PTR) { 1335 lint_assert(is_integer(rt)); 1336 tnode_t *ctn = subt_size_in_bytes(ln->tn_type); 1337 if (rn->tn_type->t_tspec != ctn->tn_type->t_tspec) 1338 rn = convert(NOOP, 0, ctn->tn_type, rn); 1339 rn = new_tnode(MULT, sys, rn->tn_type, rn, ctn); 1340 if (rn->tn_left->tn_op == CON) 1341 rn = fold(rn); 1342 } 1343 1344 if ((op == ASSIGN || op == RETURN || op == INIT) && 1345 (lt == STRUCT || rt == STRUCT)) { 1346 lint_assert(lt == rt); 1347 lint_assert(ln->tn_type->t_sou == rn->tn_type->t_sou); 1348 if (is_incomplete(ln->tn_type)) { 1349 if (op == RETURN) { 1350 /* cannot return incomplete type */ 1351 error(212); 1352 } else { 1353 /* unknown operand size, op '%s' */ 1354 error(138, op_name(op)); 1355 } 1356 return NULL; 1357 } 1358 } 1359 1360 if (op == SHLASS && hflag && allow_trad && allow_c90 1361 && portable_rank_cmp(lt, rt) < 0) 1362 /* semantics of '%s' change in ANSI C; ... */ 1363 warning(118, "<<="); 1364 1365 if (op != SHLASS && op != SHRASS 1366 && (op == ASSIGN || lt != PTR) 1367 && (lt != rt || (ln->tn_type->t_bitfield && rn->tn_op == CON))) { 1368 rn = convert(op, 0, ln->tn_type, rn); 1369 rt = lt; 1370 } 1371 1372 if (any_query_enabled && rn->tn_op == CVT && rn->tn_cast && 1373 types_compatible(ln->tn_type, rn->tn_type, false, false, NULL) && 1374 is_cast_redundant(rn)) { 1375 /* redundant cast from '%s' to '%s' before assignment */ 1376 query_message(7, 1377 type_name(rn->tn_left->tn_type), type_name(rn->tn_type)); 1378 } 1379 1380 return new_tnode(op, sys, ln->tn_type, ln, rn); 1381 } 1382 1383 /* 1384 * Create a node for REAL, IMAG 1385 */ 1386 static tnode_t * 1387 build_real_imag(op_t op, bool sys, tnode_t *ln) 1388 { 1389 1390 lint_assert(ln != NULL); 1391 if (ln->tn_op == NAME) { 1392 /* 1393 * This may be too much, but it avoids wrong warnings. 1394 * See d_c99_complex_split.c. 1395 */ 1396 mark_as_used(ln->tn_sym, false, false); 1397 mark_as_set(ln->tn_sym); 1398 } 1399 1400 tnode_t *cn; 1401 switch (ln->tn_type->t_tspec) { 1402 case LCOMPLEX: 1403 /* XXX: integer and LDOUBLE don't match. */ 1404 cn = build_integer_constant(LDOUBLE, (int64_t)1); 1405 break; 1406 case DCOMPLEX: 1407 /* XXX: integer and DOUBLE don't match. */ 1408 cn = build_integer_constant(DOUBLE, (int64_t)1); 1409 break; 1410 case FCOMPLEX: 1411 /* XXX: integer and FLOAT don't match. */ 1412 cn = build_integer_constant(FLOAT, (int64_t)1); 1413 break; 1414 default: 1415 /* '__%s__' is illegal for type '%s' */ 1416 error(276, op == REAL ? "real" : "imag", 1417 type_name(ln->tn_type)); 1418 return NULL; 1419 } 1420 1421 tnode_t *ntn = new_tnode(op, sys, cn->tn_type, ln, cn); 1422 ntn->tn_lvalue = true; 1423 return ntn; 1424 } 1425 1426 static bool 1427 is_confusing_precedence(op_t op, op_t lop, bool lparen, op_t rop, bool rparen) 1428 { 1429 1430 if (op == SHL || op == SHR) { 1431 if (!lparen && (lop == PLUS || lop == MINUS)) 1432 return true; 1433 if (!rparen && (rop == PLUS || rop == MINUS)) 1434 return true; 1435 return false; 1436 } 1437 1438 if (op == LOGOR) { 1439 if (!lparen && lop == LOGAND) 1440 return true; 1441 if (!rparen && rop == LOGAND) 1442 return true; 1443 return false; 1444 } 1445 1446 lint_assert(op == BITAND || op == BITXOR || op == BITOR); 1447 if (!lparen && lop != op) { 1448 if (lop == PLUS || lop == MINUS) 1449 return true; 1450 if (lop == BITAND || lop == BITXOR) 1451 return true; 1452 } 1453 if (!rparen && rop != op) { 1454 if (rop == PLUS || rop == MINUS) 1455 return true; 1456 if (rop == BITAND || rop == BITXOR) 1457 return true; 1458 } 1459 return false; 1460 } 1461 1462 /* 1463 * Print a warning if the given node has operands which should be 1464 * parenthesized. 1465 * 1466 * XXX Does not work if an operand is a constant expression. Constant 1467 * expressions are already folded. 1468 */ 1469 static void 1470 check_precedence_confusion(tnode_t *tn) 1471 { 1472 tnode_t *ln, *rn; 1473 1474 if (!hflag) 1475 return; 1476 1477 debug_node(tn); 1478 1479 lint_assert(is_binary(tn)); 1480 for (ln = tn->tn_left; ln->tn_op == CVT; ln = ln->tn_left) 1481 continue; 1482 for (rn = tn->tn_right; rn->tn_op == CVT; rn = rn->tn_left) 1483 continue; 1484 1485 if (is_confusing_precedence(tn->tn_op, 1486 ln->tn_op, ln->tn_parenthesized, 1487 rn->tn_op, rn->tn_parenthesized)) { 1488 /* precedence confusion possible: parenthesize! */ 1489 warning(169); 1490 } 1491 } 1492 1493 /* 1494 * Fold constant nodes, as much as is needed for comparing the value with 0. 1495 */ 1496 static tnode_t * 1497 fold_bool(tnode_t *tn) 1498 { 1499 1500 val_t *v = xcalloc(1, sizeof(*v)); 1501 v->v_tspec = tn->tn_type->t_tspec; 1502 lint_assert(v->v_tspec == INT || (Tflag && v->v_tspec == BOOL)); 1503 1504 bool l = constant_is_nonzero(tn->tn_left); 1505 bool r = is_binary(tn) && constant_is_nonzero(tn->tn_right); 1506 1507 switch (tn->tn_op) { 1508 case NOT: 1509 if (hflag && !constcond_flag) 1510 /* constant argument to '!' */ 1511 warning(239); 1512 v->u.integer = !l ? 1 : 0; 1513 break; 1514 case LOGAND: 1515 v->u.integer = l && r ? 1 : 0; 1516 break; 1517 case LOGOR: 1518 v->u.integer = l || r ? 1 : 0; 1519 break; 1520 default: 1521 lint_assert(/*CONSTCOND*/false); 1522 } 1523 1524 return build_constant(tn->tn_type, v); 1525 } 1526 1527 static long double 1528 floating_error_value(tspec_t t, long double lv) 1529 { 1530 if (t == FLOAT) 1531 return lv < 0 ? -FLT_MAX : FLT_MAX; 1532 if (t == DOUBLE) 1533 return lv < 0 ? -DBL_MAX : DBL_MAX; 1534 /* 1535 * When NetBSD is cross-built in MKLINT=yes mode on x86_64 for 1536 * sparc64, tools/lint checks this code while building usr.bin/xlint. 1537 * In that situation, lint uses the preprocessor for sparc64, in which 1538 * the type 'long double' is IEEE-754-binary128, affecting the macro 1539 * LDBL_MAX below. The type 'long double', as well as the strtold 1540 * implementation, comes from the host platform x86_64 though, where 1541 * 'long double' consumes 128 bits as well but only uses 80 of them. 1542 * The exponent range of the two 'long double' types is the same, but 1543 * the maximum finite value differs due to the extended precision on 1544 * sparc64. 1545 * 1546 * To properly handle the data types of the target platform, lint 1547 * would have to implement the floating-point types in a 1548 * platform-independent way, which is not worth the effort, given how 1549 * few programs practically use 'long double'. 1550 */ 1551 /* LINTED 248: floating-point constant out of range */ 1552 long double max = LDBL_MAX; 1553 return lv < 0 ? -max : max; 1554 } 1555 1556 static bool 1557 is_floating_overflow(tspec_t t, long double val) 1558 { 1559 if (fpe != 0 || isfinite(val) == 0) 1560 return true; 1561 if (t == FLOAT && (val > FLT_MAX || val < -FLT_MAX)) 1562 return true; 1563 if (t == DOUBLE && (val > DBL_MAX || val < -DBL_MAX)) 1564 return true; 1565 return false; 1566 } 1567 1568 /* 1569 * Fold constant nodes having operands with floating point type. 1570 */ 1571 static tnode_t * 1572 fold_float(tnode_t *tn) 1573 { 1574 1575 fpe = 0; 1576 1577 tspec_t t = tn->tn_type->t_tspec; 1578 1579 val_t *v = xcalloc(1, sizeof(*v)); 1580 v->v_tspec = t; 1581 1582 lint_assert(is_floating(t)); 1583 lint_assert(t == tn->tn_left->tn_type->t_tspec); 1584 lint_assert(!is_binary(tn) || t == tn->tn_right->tn_type->t_tspec); 1585 1586 long double lv = tn->tn_left->tn_val.u.floating; 1587 long double rv = is_binary(tn) ? tn->tn_right->tn_val.u.floating : 0.0; 1588 1589 switch (tn->tn_op) { 1590 case UPLUS: 1591 v->u.floating = lv; 1592 break; 1593 case UMINUS: 1594 v->u.floating = -lv; 1595 break; 1596 case MULT: 1597 v->u.floating = lv * rv; 1598 break; 1599 case DIV: 1600 if (rv == 0.0) { 1601 /* division by 0 */ 1602 error(139); 1603 v->u.floating = floating_error_value(t, lv); 1604 } else { 1605 v->u.floating = lv / rv; 1606 } 1607 break; 1608 case PLUS: 1609 v->u.floating = lv + rv; 1610 break; 1611 case MINUS: 1612 v->u.floating = lv - rv; 1613 break; 1614 case LT: 1615 v->u.integer = lv < rv ? 1 : 0; 1616 break; 1617 case LE: 1618 v->u.integer = lv <= rv ? 1 : 0; 1619 break; 1620 case GE: 1621 v->u.integer = lv >= rv ? 1 : 0; 1622 break; 1623 case GT: 1624 v->u.integer = lv > rv ? 1 : 0; 1625 break; 1626 case EQ: 1627 v->u.integer = lv == rv ? 1 : 0; 1628 break; 1629 case NE: 1630 v->u.integer = lv != rv ? 1 : 0; 1631 break; 1632 default: 1633 lint_assert(/*CONSTCOND*/false); 1634 } 1635 1636 lint_assert(fpe != 0 || isnan(v->u.floating) == 0); 1637 if (is_complex(v->v_tspec)) { 1638 /* 1639 * Don't warn, as lint doesn't model the imaginary part of 1640 * complex numbers. 1641 */ 1642 fpe = 0; 1643 } else if (is_floating_overflow(t, v->u.floating)) { 1644 /* operator '%s' produces floating point overflow */ 1645 warning(142, op_name(tn->tn_op)); 1646 v->u.floating = floating_error_value(t, v->u.floating); 1647 fpe = 0; 1648 } 1649 1650 return build_constant(tn->tn_type, v); 1651 } 1652 1653 /* 1654 * Create a tree node for a binary operator and its two operands. Also called 1655 * for unary operators; in that case rn is NULL. 1656 * 1657 * Function calls, sizeof and casts are handled elsewhere. 1658 */ 1659 tnode_t * 1660 build_binary(tnode_t *ln, op_t op, bool sys, tnode_t *rn) 1661 { 1662 const mod_t *mp = &modtab[op]; 1663 1664 /* If there was an error in one of the operands, return. */ 1665 if (ln == NULL || (mp->m_binary && rn == NULL)) 1666 return NULL; 1667 1668 /* 1669 * Apply class conversions to the left operand, but only if its 1670 * value is needed or compared with zero. 1671 */ 1672 if (mp->m_value_context || mp->m_compares_with_zero) 1673 ln = cconv(ln); 1674 /* 1675 * The right operand is almost always in a test or value context, 1676 * except if it is a struct or union member. 1677 */ 1678 if (mp->m_binary && op != ARROW && op != POINT) 1679 rn = cconv(rn); 1680 1681 /* 1682 * Print some warnings for comparisons of unsigned values with 1683 * constants lower than or equal to null. This must be done 1684 * before promote() because otherwise unsigned char and unsigned 1685 * short would be promoted to int. Types are also tested to be 1686 * CHAR, which would also become int. 1687 */ 1688 if (mp->m_comparison) 1689 check_integer_comparison(op, ln, rn); 1690 1691 if (mp->m_value_context || mp->m_compares_with_zero) 1692 ln = promote(op, false, ln); 1693 if (mp->m_binary && op != ARROW && op != POINT && 1694 op != ASSIGN && op != RETURN && op != INIT) { 1695 rn = promote(op, false, rn); 1696 } 1697 1698 /* 1699 * If the result of the operation is different for signed or 1700 * unsigned operands and one of the operands is signed only in 1701 * ANSI C, print a warning. 1702 */ 1703 if (mp->m_warn_if_left_unsigned_in_c90 && 1704 ln->tn_op == CON && ln->tn_val.v_unsigned_since_c90) { 1705 /* ANSI C treats constant as unsigned, op '%s' */ 1706 warning(218, mp->m_name); 1707 ln->tn_val.v_unsigned_since_c90 = false; 1708 } 1709 if (mp->m_warn_if_right_unsigned_in_c90 && 1710 rn->tn_op == CON && rn->tn_val.v_unsigned_since_c90) { 1711 /* ANSI C treats constant as unsigned, op '%s' */ 1712 warning(218, mp->m_name); 1713 rn->tn_val.v_unsigned_since_c90 = false; 1714 } 1715 1716 /* Make sure both operands are of the same type */ 1717 if (mp->m_balance_operands || (!allow_c90 && (op == SHL || op == SHR))) 1718 balance(op, &ln, &rn); 1719 1720 /* 1721 * Check types for compatibility with the operation and mutual 1722 * compatibility. Return if there are serious problems. 1723 */ 1724 if (!typeok(op, 0, ln, rn)) 1725 return NULL; 1726 1727 /* And now create the node. */ 1728 tnode_t *ntn; 1729 switch (op) { 1730 case POINT: 1731 case ARROW: 1732 ntn = build_struct_access(op, sys, ln, rn); 1733 break; 1734 case INCAFT: 1735 case DECAFT: 1736 case INCBEF: 1737 case DECBEF: 1738 ntn = build_prepost_incdec(op, sys, ln); 1739 break; 1740 case ADDR: 1741 ntn = build_address(sys, ln, false); 1742 break; 1743 case INDIR: 1744 ntn = new_tnode(INDIR, sys, ln->tn_type->t_subt, ln, NULL); 1745 break; 1746 case PLUS: 1747 case MINUS: 1748 ntn = build_plus_minus(op, sys, ln, rn); 1749 break; 1750 case SHL: 1751 case SHR: 1752 ntn = build_bit_shift(op, sys, ln, rn); 1753 break; 1754 case COLON: 1755 ntn = build_colon(sys, ln, rn); 1756 break; 1757 case ASSIGN: 1758 case MULASS: 1759 case DIVASS: 1760 case MODASS: 1761 case ADDASS: 1762 case SUBASS: 1763 case SHLASS: 1764 case SHRASS: 1765 case ANDASS: 1766 case XORASS: 1767 case ORASS: 1768 case RETURN: 1769 case INIT: 1770 ntn = build_assignment(op, sys, ln, rn); 1771 break; 1772 case COMMA: 1773 if (any_query_enabled) { 1774 /* comma operator with types '%s' and '%s' */ 1775 query_message(12, 1776 type_name(ln->tn_type), type_name(rn->tn_type)); 1777 } 1778 /* FALLTHROUGH */ 1779 case QUEST: 1780 ntn = new_tnode(op, sys, rn->tn_type, ln, rn); 1781 break; 1782 case REAL: 1783 case IMAG: 1784 ntn = build_real_imag(op, sys, ln); 1785 break; 1786 default: 1787 lint_assert(mp->m_binary == (rn != NULL)); 1788 type_t *rettp = mp->m_returns_bool 1789 ? gettyp(Tflag ? BOOL : INT) : ln->tn_type; 1790 ntn = new_tnode(op, sys, rettp, ln, rn); 1791 break; 1792 } 1793 1794 /* Return if an error occurred. */ 1795 if (ntn == NULL) 1796 return NULL; 1797 1798 /* Print a warning if precedence confusion is possible */ 1799 if (mp->m_possible_precedence_confusion) 1800 check_precedence_confusion(ntn); 1801 1802 /* 1803 * Print a warning if one of the operands is in a context where 1804 * it is compared with zero and if this operand is a constant. 1805 */ 1806 if (hflag && !constcond_flag && 1807 mp->m_compares_with_zero && 1808 (ln->tn_op == CON || 1809 ((mp->m_binary && op != QUEST) && rn->tn_op == CON)) && 1810 /* XXX: rn->tn_system_dependent should be checked as well */ 1811 !ln->tn_system_dependent) { 1812 /* constant in conditional context */ 1813 warning(161); 1814 } 1815 1816 /* Fold if the operator requires it */ 1817 if (mp->m_fold_constant_operands) { 1818 if (ln->tn_op == CON && (!mp->m_binary || rn->tn_op == CON)) { 1819 if (mp->m_compares_with_zero) { 1820 ntn = fold_bool(ntn); 1821 } else if (is_floating(ntn->tn_type->t_tspec)) { 1822 ntn = fold_float(ntn); 1823 } else { 1824 ntn = fold(ntn); 1825 } 1826 } else if (op == QUEST && ln->tn_op == CON) { 1827 ntn = ln->tn_val.u.integer != 0 1828 ? rn->tn_left : rn->tn_right; 1829 } 1830 } 1831 1832 return ntn; 1833 } 1834 1835 tnode_t * 1836 build_unary(op_t op, bool sys, tnode_t *tn) 1837 { 1838 return build_binary(tn, op, sys, NULL); 1839 } 1840 1841 static bool 1842 are_members_compatible(const sym_t *a, const sym_t *b) 1843 { 1844 if (a->u.s_member.sm_offset_in_bits != b->u.s_member.sm_offset_in_bits) 1845 return false; 1846 1847 const type_t *atp = a->s_type; 1848 const type_t *btp = b->s_type; 1849 bool w = false; 1850 if (!types_compatible(atp, btp, false, false, &w) && !w) 1851 return false; 1852 if (a->s_bitfield != b->s_bitfield) 1853 return false; 1854 if (a->s_bitfield) { 1855 if (atp->t_bit_field_width != btp->t_bit_field_width) 1856 return false; 1857 if (atp->t_bit_field_offset != btp->t_bit_field_offset) 1858 return false; 1859 } 1860 return true; 1861 } 1862 1863 /* 1864 * Return whether all struct/union members with the same name have the same 1865 * type and offset. 1866 */ 1867 static bool 1868 all_members_compatible(const sym_t *msym) 1869 { 1870 for (const sym_t *csym = msym; 1871 csym != NULL; csym = csym->s_symtab_next) { 1872 if (!is_member(csym)) 1873 continue; 1874 if (strcmp(msym->s_name, csym->s_name) != 0) 1875 continue; 1876 1877 for (const sym_t *sym = csym->s_symtab_next; 1878 sym != NULL; sym = sym->s_symtab_next) { 1879 if (is_member(sym) 1880 && strcmp(csym->s_name, sym->s_name) == 0 1881 && !are_members_compatible(csym, sym)) 1882 return false; 1883 } 1884 } 1885 return true; 1886 } 1887 1888 sym_t * 1889 find_member(const type_t *tp, const char *name) 1890 { 1891 for (sym_t *mem = tp->t_sou->sou_first_member; 1892 mem != NULL; mem = mem->s_next) { 1893 if (strcmp(mem->s_name, name) == 0) 1894 return mem; 1895 } 1896 for (sym_t *mem = tp->t_sou->sou_first_member; 1897 mem != NULL; mem = mem->s_next) { 1898 if (is_struct_or_union(mem->s_type->t_tspec) && 1899 mem->s_name == unnamed) { 1900 sym_t *nested_mem = find_member(mem->s_type, name); 1901 if (nested_mem != NULL) 1902 return nested_mem; 1903 } 1904 } 1905 return NULL; 1906 } 1907 1908 /* 1909 * Returns a symbol which has the same name as the msym argument and is a 1910 * member of the struct or union specified by the tn argument. 1911 */ 1912 static sym_t * 1913 struct_or_union_member(tnode_t *tn, op_t op, sym_t *msym) 1914 { 1915 1916 /* 1917 * Remove the member if it was unknown until now, which means 1918 * that no defined struct or union has a member with the same name. 1919 */ 1920 if (msym->s_scl == NOSCL) { 1921 /* type '%s' does not have member '%s' */ 1922 error(101, type_name(tn->tn_type), msym->s_name); 1923 rmsym(msym); 1924 msym->s_kind = FMEMBER; 1925 msym->s_scl = STRUCT_MEMBER; 1926 1927 struct_or_union *sou = expr_zero_alloc(sizeof(*sou)); 1928 sou->sou_tag = expr_zero_alloc(sizeof(*sou->sou_tag)); 1929 sou->sou_tag->s_name = unnamed; 1930 1931 msym->u.s_member.sm_containing_type = sou; 1932 /* 1933 * The member sm_offset_in_bits is not needed here since this 1934 * symbol can only be used for error reporting. 1935 */ 1936 return msym; 1937 } 1938 1939 /* Determine the tag type of which msym is expected to be a member. */ 1940 const type_t *tp = NULL; 1941 if (op == POINT && is_struct_or_union(tn->tn_type->t_tspec)) 1942 tp = tn->tn_type; 1943 if (op == ARROW && tn->tn_type->t_tspec == PTR 1944 && is_struct_or_union(tn->tn_type->t_subt->t_tspec)) 1945 tp = tn->tn_type->t_subt; 1946 struct_or_union *sou = tp != NULL ? tp->t_sou : NULL; 1947 1948 /* 1949 * If this struct/union has a member with the name of msym, return it. 1950 */ 1951 if (sou != NULL) { 1952 for (sym_t *sym = msym; 1953 sym != NULL; sym = sym->s_symtab_next) { 1954 if (is_member(sym) && 1955 sym->u.s_member.sm_containing_type == sou && 1956 strcmp(sym->s_name, msym->s_name) == 0) 1957 return sym; 1958 } 1959 } 1960 1961 if (tp != NULL) { 1962 sym_t *nested_mem = find_member(tp, msym->s_name); 1963 if (nested_mem != NULL) 1964 return nested_mem; 1965 } 1966 1967 bool eq = all_members_compatible(msym); 1968 1969 /* 1970 * Now handle the case in which the left operand refers really 1971 * to a struct/union, but the right operand is not member of it. 1972 */ 1973 if (sou != NULL) { 1974 if (eq && !allow_c90) { 1975 /* illegal use of member '%s' */ 1976 warning(102, msym->s_name); 1977 } else { 1978 /* illegal use of member '%s' */ 1979 error(102, msym->s_name); 1980 } 1981 return msym; 1982 } 1983 1984 /* 1985 * Now the left operand of ARROW does not point to a struct/union 1986 * or the left operand of POINT is no struct/union. 1987 */ 1988 if (eq) { 1989 if (op == POINT) { 1990 if (!allow_c90) { 1991 /* left operand of '.' must be struct ... */ 1992 warning(103, type_name(tn->tn_type)); 1993 } else { 1994 /* left operand of '.' must be struct ... */ 1995 error(103, type_name(tn->tn_type)); 1996 } 1997 } else { 1998 if (!allow_c90 && tn->tn_type->t_tspec == PTR) { 1999 /* left operand of '->' must be pointer ... */ 2000 warning(104, type_name(tn->tn_type)); 2001 } else { 2002 /* left operand of '->' must be pointer ... */ 2003 error(104, type_name(tn->tn_type)); 2004 } 2005 } 2006 } else { 2007 if (!allow_c90) { 2008 /* non-unique member requires struct/union %s */ 2009 error(105, op == POINT ? "object" : "pointer"); 2010 } else { 2011 /* unacceptable operand of '%s' */ 2012 error(111, op_name(op)); 2013 } 2014 } 2015 2016 return msym; 2017 } 2018 2019 tnode_t * 2020 build_member_access(tnode_t *ln, op_t op, bool sys, sbuf_t *member) 2021 { 2022 sym_t *msym; 2023 2024 if (ln == NULL) 2025 return NULL; 2026 2027 if (op == ARROW) { 2028 /* must do this before struct_or_union_member is called */ 2029 ln = cconv(ln); 2030 } 2031 msym = struct_or_union_member(ln, op, getsym(member)); 2032 return build_binary(ln, op, sys, build_name(msym, false)); 2033 } 2034 2035 /* 2036 * Perform class conversions. 2037 * 2038 * Arrays of type T are converted into pointers to type T. 2039 * Functions are converted to pointers to functions. 2040 * Lvalues are converted to rvalues. 2041 * 2042 * C99 6.3 "Conversions" 2043 * C99 6.3.2 "Other operands" 2044 * C99 6.3.2.1 "Lvalues, arrays, and function designators" 2045 */ 2046 tnode_t * 2047 cconv(tnode_t *tn) 2048 { 2049 /* 2050 * Array-lvalue (array of type T) is converted into rvalue 2051 * (pointer to type T) 2052 */ 2053 if (tn->tn_type->t_tspec == ARRAY) { 2054 if (!tn->tn_lvalue) { 2055 /* XXX print correct operator */ 2056 /* %soperand of '%s' must be lvalue */ 2057 gnuism(114, "", op_name(ADDR)); 2058 } 2059 tn = new_tnode(ADDR, tn->tn_sys, 2060 expr_derive_type(tn->tn_type->t_subt, PTR), tn, NULL); 2061 } 2062 2063 /* 2064 * Expression of type function (function with return value of type T) 2065 * in rvalue-expression (pointer to function with return value 2066 * of type T) 2067 */ 2068 if (tn->tn_type->t_tspec == FUNC) 2069 tn = build_address(tn->tn_sys, tn, true); 2070 2071 /* lvalue to rvalue */ 2072 if (tn->tn_lvalue) { 2073 type_t *tp = expr_dup_type(tn->tn_type); 2074 /* C99 6.3.2.1p2 sentence 2 says to remove the qualifiers. */ 2075 tp->t_const = tp->t_volatile = false; 2076 tn = new_tnode(LOAD, tn->tn_sys, tp, tn, NULL); 2077 } 2078 2079 return tn; 2080 } 2081 2082 const tnode_t * 2083 before_conversion(const tnode_t *tn) 2084 { 2085 while (tn->tn_op == CVT && !tn->tn_cast) 2086 tn = tn->tn_left; 2087 return tn; 2088 } 2089 2090 /* 2091 * Most errors required by ANSI C are reported in struct_or_union_member(). 2092 * Here we only check for totally wrong things. 2093 */ 2094 static bool 2095 typeok_point(const tnode_t *ln, const type_t *ltp, tspec_t lt) 2096 { 2097 if (is_struct_or_union(lt)) 2098 return true; 2099 2100 if (lt == FUNC || lt == VOID || ltp->t_bitfield) 2101 goto wrong; 2102 2103 /* 2104 * Some C dialects from before C90 tolerated any lvalue on the 2105 * left-hand side of the '.' operator, allowing things like 2106 * char st[100]; st.st_mtime, assuming that the member 'st_mtime' 2107 * only occurred in a single struct; see typeok_arrow. 2108 */ 2109 if (ln->tn_lvalue) 2110 return true; 2111 2112 wrong: 2113 /* With allow_c90 we already got an error */ 2114 if (!allow_c90) 2115 /* unacceptable operand of '%s' */ 2116 error(111, op_name(POINT)); 2117 2118 return false; 2119 } 2120 2121 static bool 2122 typeok_arrow(tspec_t lt) 2123 { 2124 /* 2125 * C1978 Appendix A 14.1 says: <quote>In fact, any lvalue is allowed 2126 * before '.', and that lvalue is then assumed to have the form of 2127 * the structure of which the name of the right is a member. [...] 2128 * Such constructions are non-portable.</quote> 2129 */ 2130 if (lt == PTR || (!allow_c90 && is_integer(lt))) 2131 return true; 2132 2133 /* With allow_c90 we already got an error */ 2134 if (!allow_c90) 2135 /* unacceptable operand of '%s' */ 2136 error(111, op_name(ARROW)); 2137 return false; 2138 } 2139 2140 static bool 2141 typeok_incdec(op_t op, const tnode_t *tn, const type_t *tp) 2142 { 2143 /* operand has scalar type (checked in typeok) */ 2144 if (!tn->tn_lvalue) { 2145 if (tn->tn_op == CVT && tn->tn_cast && 2146 tn->tn_left->tn_op == LOAD) { 2147 /* a cast does not yield an lvalue */ 2148 error(163); 2149 } 2150 /* %soperand of '%s' must be lvalue */ 2151 error(114, "", op_name(op)); 2152 return false; 2153 } 2154 if (tp->t_const && allow_c90) { 2155 /* %soperand of '%s' must be modifiable lvalue */ 2156 warning(115, "", op_name(op)); 2157 } 2158 return true; 2159 } 2160 2161 static bool 2162 typeok_address(const mod_t *mp, 2163 const tnode_t *tn, const type_t *tp, tspec_t t) 2164 { 2165 if (t == ARRAY || t == FUNC) { 2166 /* ok, a warning comes later (in build_address()) */ 2167 } else if (!tn->tn_lvalue) { 2168 if (tn->tn_op == CVT && tn->tn_cast && 2169 tn->tn_left->tn_op == LOAD) { 2170 /* a cast does not yield an lvalue */ 2171 error(163); 2172 } 2173 /* %soperand of '%s' must be lvalue */ 2174 error(114, "", mp->m_name); 2175 return false; 2176 } else if (is_scalar(t)) { 2177 if (tp->t_bitfield) { 2178 /* cannot take address of bit-field */ 2179 error(112); 2180 return false; 2181 } 2182 } else if (t != STRUCT && t != UNION) { 2183 /* unacceptable operand of '%s' */ 2184 error(111, mp->m_name); 2185 return false; 2186 } 2187 if (tn->tn_op == NAME && tn->tn_sym->s_register) { 2188 /* cannot take address of register '%s' */ 2189 error(113, tn->tn_sym->s_name); 2190 return false; 2191 } 2192 return true; 2193 } 2194 2195 static bool 2196 typeok_indir(const type_t *tp, tspec_t t) 2197 { 2198 2199 if (t != PTR) { 2200 /* cannot dereference non-pointer type '%s' */ 2201 error(96, type_name(tp)); 2202 return false; 2203 } 2204 return true; 2205 } 2206 2207 static void 2208 warn_incompatible_types(op_t op, 2209 const type_t *ltp, tspec_t lt, 2210 const type_t *rtp, tspec_t rt) 2211 { 2212 const mod_t *mp = &modtab[op]; 2213 2214 if (lt == VOID || (mp->m_binary && rt == VOID)) { 2215 /* void type illegal in expression */ 2216 error(109); 2217 } else if (op == ASSIGN) { 2218 /* cannot assign to '%s' from '%s' */ 2219 error(171, type_name(ltp), type_name(rtp)); 2220 } else if (mp->m_binary) { 2221 /* operands of '%s' have incompatible types '%s' and '%s' */ 2222 error(107, mp->m_name, type_name(ltp), type_name(rtp)); 2223 } else { 2224 lint_assert(rt == NO_TSPEC); 2225 /* operand of '%s' has invalid type '%s' */ 2226 error(108, mp->m_name, type_name(ltp)); 2227 } 2228 } 2229 2230 static bool 2231 typeok_plus(op_t op, 2232 const type_t *ltp, tspec_t lt, 2233 const type_t *rtp, tspec_t rt) 2234 { 2235 /* operands have scalar types (checked in typeok) */ 2236 if ((lt == PTR && !is_integer(rt)) || (rt == PTR && !is_integer(lt))) { 2237 warn_incompatible_types(op, ltp, lt, rtp, rt); 2238 return false; 2239 } 2240 return true; 2241 } 2242 2243 static bool 2244 typeok_minus(op_t op, 2245 const type_t *ltp, tspec_t lt, 2246 const type_t *rtp, tspec_t rt) 2247 { 2248 /* operands have scalar types (checked in typeok) */ 2249 if ((lt == PTR && rt != PTR && !is_integer(rt)) || 2250 (lt != PTR && rt == PTR)) { 2251 warn_incompatible_types(op, ltp, lt, rtp, rt); 2252 return false; 2253 } 2254 if (lt == PTR && rt == PTR && 2255 !types_compatible(ltp->t_subt, rtp->t_subt, true, false, NULL)) { 2256 /* illegal pointer subtraction */ 2257 error(116); 2258 } 2259 return true; 2260 } 2261 2262 static void 2263 typeok_shr(const mod_t *mp, 2264 const tnode_t *ln, tspec_t lt, 2265 const tnode_t *rn, tspec_t rt) 2266 { 2267 tspec_t olt = before_conversion(ln)->tn_type->t_tspec; 2268 tspec_t ort = before_conversion(rn)->tn_type->t_tspec; 2269 2270 /* operands have integer types (checked in typeok) */ 2271 if (pflag && !is_uinteger(olt)) { 2272 integer_constraints lc = ic_expr(ln); 2273 if (!ic_maybe_signed(ln->tn_type, &lc)) 2274 return; 2275 2276 /* 2277 * The left operand is signed. This means that 2278 * the operation is (possibly) nonportable. 2279 */ 2280 if (ln->tn_op != CON) { 2281 /* bitwise '%s' on signed value possibly nonportable */ 2282 warning(117, mp->m_name); 2283 } else if (ln->tn_val.u.integer < 0) { 2284 /* bitwise '%s' on signed value nonportable */ 2285 warning(120, mp->m_name); 2286 } 2287 } else if (allow_trad && allow_c90 && 2288 !is_uinteger(olt) && is_uinteger(ort)) { 2289 /* The left operand would become unsigned in traditional C. */ 2290 if (hflag && (ln->tn_op != CON || ln->tn_val.u.integer < 0)) { 2291 /* semantics of '%s' change in ANSI C; use ... */ 2292 warning(118, mp->m_name); 2293 } 2294 } else if (allow_trad && allow_c90 && 2295 !is_uinteger(olt) && !is_uinteger(ort) && 2296 portable_rank_cmp(lt, rt) < 0) { 2297 /* 2298 * In traditional C the left operand would be extended 2299 * (possibly sign-extended) and then shifted. 2300 */ 2301 if (hflag && (ln->tn_op != CON || ln->tn_val.u.integer < 0)) { 2302 /* semantics of '%s' change in ANSI C; use ... */ 2303 warning(118, mp->m_name); 2304 } 2305 } 2306 } 2307 2308 static void 2309 typeok_shl(const mod_t *mp, tspec_t lt, tspec_t rt) 2310 { 2311 /* 2312 * C90 does not perform balancing for shift operations, 2313 * but traditional C does. If the width of the right operand 2314 * is greater than the width of the left operand, then in 2315 * traditional C the left operand would be extended to the 2316 * width of the right operand. For SHL this may result in 2317 * different results. 2318 */ 2319 if (portable_rank_cmp(lt, rt) < 0) { 2320 /* 2321 * XXX If both operands are constant, make sure 2322 * that there is really a difference between 2323 * ANSI C and traditional C. 2324 */ 2325 if (hflag && allow_trad && allow_c90) 2326 /* semantics of '%s' change in ANSI C; use ... */ 2327 warning(118, mp->m_name); 2328 } 2329 } 2330 2331 static void 2332 typeok_shift(const type_t *ltp, tspec_t lt, const tnode_t *rn, tspec_t rt) 2333 { 2334 if (rn->tn_op != CON) 2335 return; 2336 2337 if (!is_uinteger(rt) && rn->tn_val.u.integer < 0) { 2338 /* negative shift */ 2339 warning(121); 2340 } else if ((uint64_t)rn->tn_val.u.integer == size_in_bits(lt)) { 2341 /* shift amount %u equals bit-size of '%s' */ 2342 warning(267, (unsigned)rn->tn_val.u.integer, type_name(ltp)); 2343 } else if ((uint64_t)rn->tn_val.u.integer > size_in_bits(lt)) { 2344 /* shift amount %llu is greater than bit-size %llu of '%s' */ 2345 warning(122, (unsigned long long)rn->tn_val.u.integer, 2346 (unsigned long long)size_in_bits(lt), 2347 tspec_name(lt)); 2348 } 2349 } 2350 2351 static bool 2352 is_typeok_eq(const tnode_t *ln, tspec_t lt, const tnode_t *rn, tspec_t rt) 2353 { 2354 if (lt == PTR && is_null_pointer(rn)) 2355 return true; 2356 if (rt == PTR && is_null_pointer(ln)) 2357 return true; 2358 return false; 2359 } 2360 2361 /* 2362 * Called if incompatible pointer types are detected. 2363 * Print an appropriate warning. 2364 */ 2365 static void 2366 warn_incompatible_pointers(const mod_t *mp, 2367 const type_t *ltp, const type_t *rtp) 2368 { 2369 lint_assert(ltp->t_tspec == PTR); 2370 lint_assert(rtp->t_tspec == PTR); 2371 2372 tspec_t lt = ltp->t_subt->t_tspec; 2373 tspec_t rt = rtp->t_subt->t_tspec; 2374 2375 if (is_struct_or_union(lt) && is_struct_or_union(rt)) { 2376 if (mp == NULL) { 2377 /* illegal structure pointer combination */ 2378 warning(244); 2379 } else { 2380 /* incompatible structure pointers: '%s' '%s' '%s' */ 2381 warning(245, type_name(ltp), mp->m_name, type_name(rtp)); 2382 } 2383 } else { 2384 if (mp == NULL) { 2385 /* illegal combination of '%s' and '%s' */ 2386 warning(184, type_name(ltp), type_name(rtp)); 2387 } else { 2388 /* illegal combination of '%s' and '%s', op '%s' */ 2389 warning(124, 2390 type_name(ltp), type_name(rtp), mp->m_name); 2391 } 2392 } 2393 } 2394 2395 static void 2396 check_pointer_comparison(op_t op, const tnode_t *ln, const tnode_t *rn) 2397 { 2398 type_t *ltp = ln->tn_type, *rtp = rn->tn_type; 2399 tspec_t lst = ltp->t_subt->t_tspec, rst = rtp->t_subt->t_tspec; 2400 2401 if (lst == VOID || rst == VOID) { 2402 /* TODO: C99 behaves like C90 here. */ 2403 if ((!allow_trad && !allow_c99) && 2404 (lst == FUNC || rst == FUNC)) { 2405 /* (void *)0 is already handled in typeok() */ 2406 const char *lsts, *rsts; 2407 *(lst == FUNC ? &lsts : &rsts) = "function pointer"; 2408 *(lst == VOID ? &lsts : &rsts) = "'void *'"; 2409 /* ANSI C forbids comparison of %s with %s */ 2410 warning(274, lsts, rsts); 2411 } 2412 return; 2413 } 2414 2415 if (!types_compatible(ltp->t_subt, rtp->t_subt, true, false, NULL)) { 2416 warn_incompatible_pointers(&modtab[op], ltp, rtp); 2417 return; 2418 } 2419 2420 if (lst == FUNC && rst == FUNC) { 2421 /* TODO: C99 behaves like C90 here, see C99 6.5.8p2. */ 2422 if ((!allow_trad && !allow_c99) && op != EQ && op != NE) 2423 /* ANSI C forbids ordered comparisons of ... */ 2424 warning(125); 2425 } 2426 } 2427 2428 static bool 2429 typeok_compare(op_t op, 2430 const tnode_t *ln, const type_t *ltp, tspec_t lt, 2431 const tnode_t *rn, const type_t *rtp, tspec_t rt) 2432 { 2433 if (lt == PTR && rt == PTR) { 2434 check_pointer_comparison(op, ln, rn); 2435 return true; 2436 } 2437 2438 if (lt != PTR && rt != PTR) 2439 return true; 2440 2441 if (!is_integer(lt) && !is_integer(rt)) { 2442 warn_incompatible_types(op, ltp, lt, rtp, rt); 2443 return false; 2444 } 2445 2446 const char *lx = lt == PTR ? "pointer" : "integer"; 2447 const char *rx = rt == PTR ? "pointer" : "integer"; 2448 /* illegal combination of %s '%s' and %s '%s', op '%s' */ 2449 warning(123, lx, type_name(ltp), rx, type_name(rtp), op_name(op)); 2450 return true; 2451 } 2452 2453 static bool 2454 typeok_quest(tspec_t lt, const tnode_t *rn) 2455 { 2456 if (!is_scalar(lt)) { 2457 /* first operand of '?' must have scalar type */ 2458 error(170); 2459 return false; 2460 } 2461 lint_assert(before_conversion(rn)->tn_op == COLON); 2462 return true; 2463 } 2464 2465 static void 2466 typeok_colon_pointer(const mod_t *mp, const type_t *ltp, const type_t *rtp) 2467 { 2468 type_t *lstp = ltp->t_subt; 2469 type_t *rstp = rtp->t_subt; 2470 tspec_t lst = lstp->t_tspec; 2471 tspec_t rst = rstp->t_tspec; 2472 2473 if ((lst == VOID && rst == FUNC) || (lst == FUNC && rst == VOID)) { 2474 /* (void *)0 is handled in typeok_colon */ 2475 /* TODO: C99 behaves like C90 here. */ 2476 if (!allow_trad && !allow_c99) 2477 /* ANSI C forbids conversion of %s to %s, op %s */ 2478 warning(305, "function pointer", "'void *'", 2479 mp->m_name); 2480 return; 2481 } 2482 2483 if (pointer_types_are_compatible(lstp, rstp, true)) 2484 return; 2485 if (!types_compatible(lstp, rstp, true, false, NULL)) 2486 warn_incompatible_pointers(mp, ltp, rtp); 2487 } 2488 2489 static bool 2490 typeok_colon(const mod_t *mp, 2491 const tnode_t *ln, const type_t *ltp, tspec_t lt, 2492 const tnode_t *rn, const type_t *rtp, tspec_t rt) 2493 { 2494 2495 if (is_arithmetic(lt) && is_arithmetic(rt)) 2496 return true; 2497 if (lt == BOOL && rt == BOOL) 2498 return true; 2499 2500 if (lt == STRUCT && rt == STRUCT && ltp->t_sou == rtp->t_sou) 2501 return true; 2502 if (lt == UNION && rt == UNION && ltp->t_sou == rtp->t_sou) 2503 return true; 2504 2505 if (lt == PTR && is_null_pointer(rn)) 2506 return true; 2507 if (rt == PTR && is_null_pointer(ln)) 2508 return true; 2509 2510 if ((lt == PTR && is_integer(rt)) || (is_integer(lt) && rt == PTR)) { 2511 const char *lx = lt == PTR ? "pointer" : "integer"; 2512 const char *rx = rt == PTR ? "pointer" : "integer"; 2513 /* illegal combination of %s '%s' and %s '%s', op '%s' */ 2514 warning(123, lx, type_name(ltp), 2515 rx, type_name(rtp), mp->m_name); 2516 return true; 2517 } 2518 2519 if (lt == VOID || rt == VOID) { 2520 if (lt != VOID || rt != VOID) 2521 /* incompatible types '%s' and '%s' in conditional */ 2522 warning(126, type_name(ltp), type_name(rtp)); 2523 return true; 2524 } 2525 2526 if (lt == PTR && rt == PTR) { 2527 typeok_colon_pointer(mp, ltp, rtp); 2528 return true; 2529 } 2530 2531 /* incompatible types '%s' and '%s' in conditional */ 2532 error(126, type_name(ltp), type_name(rtp)); 2533 return false; 2534 } 2535 2536 /* 2537 * Returns true if the given structure or union has a constant member 2538 * (maybe recursively). 2539 */ 2540 static bool 2541 has_constant_member(const type_t *tp) 2542 { 2543 lint_assert(is_struct_or_union(tp->t_tspec)); 2544 2545 for (sym_t *m = tp->t_sou->sou_first_member; 2546 m != NULL; m = m->s_next) { 2547 const type_t *mtp = m->s_type; 2548 if (mtp->t_const) 2549 return true; 2550 if (is_struct_or_union(mtp->t_tspec) && 2551 has_constant_member(mtp)) 2552 return true; 2553 } 2554 return false; 2555 } 2556 2557 static bool 2558 typeok_assign(op_t op, const tnode_t *ln, const type_t *ltp, tspec_t lt) 2559 { 2560 if (op == RETURN || op == INIT || op == FARG) 2561 return true; 2562 2563 if (!ln->tn_lvalue) { 2564 if (ln->tn_op == CVT && ln->tn_cast && 2565 ln->tn_left->tn_op == LOAD) { 2566 /* a cast does not yield an lvalue */ 2567 error(163); 2568 } 2569 /* %soperand of '%s' must be lvalue */ 2570 error(114, "left ", op_name(op)); 2571 return false; 2572 } else if (ltp->t_const 2573 || (is_struct_or_union(lt) && has_constant_member(ltp))) { 2574 if (allow_c90) 2575 /* %soperand of '%s' must be modifiable lvalue */ 2576 warning(115, "left ", op_name(op)); 2577 } 2578 return true; 2579 } 2580 2581 /* Check the types using the information from modtab[]. */ 2582 static bool 2583 typeok_scalar(op_t op, const mod_t *mp, 2584 const type_t *ltp, tspec_t lt, 2585 const type_t *rtp, tspec_t rt) 2586 { 2587 if (mp->m_takes_bool && lt == BOOL && rt == BOOL) 2588 return true; 2589 if (mp->m_requires_integer) { 2590 if (!is_integer(lt) || (mp->m_binary && !is_integer(rt))) { 2591 warn_incompatible_types(op, ltp, lt, rtp, rt); 2592 return false; 2593 } 2594 } else if (mp->m_requires_integer_or_complex) { 2595 if ((!is_integer(lt) && !is_complex(lt)) || 2596 (mp->m_binary && (!is_integer(rt) && !is_complex(rt)))) { 2597 warn_incompatible_types(op, ltp, lt, rtp, rt); 2598 return false; 2599 } 2600 } else if (mp->m_requires_scalar) { 2601 if (!is_scalar(lt) || (mp->m_binary && !is_scalar(rt))) { 2602 warn_incompatible_types(op, ltp, lt, rtp, rt); 2603 return false; 2604 } 2605 } else if (mp->m_requires_arith) { 2606 if (!is_arithmetic(lt) || 2607 (mp->m_binary && !is_arithmetic(rt))) { 2608 warn_incompatible_types(op, ltp, lt, rtp, rt); 2609 return false; 2610 } 2611 } 2612 return true; 2613 } 2614 2615 static void 2616 check_assign_void_pointer(op_t op, int arg, 2617 tspec_t lt, tspec_t lst, 2618 tspec_t rt, tspec_t rst) 2619 { 2620 2621 if (!(lt == PTR && rt == PTR && (lst == VOID || rst == VOID))) 2622 return; 2623 /* two pointers, at least one pointer to void */ 2624 2625 /* TODO: C99 behaves like C90 here. */ 2626 if (!((!allow_trad && !allow_c99) && (lst == FUNC || rst == FUNC))) 2627 return; 2628 /* comb. of ptr to func and ptr to void */ 2629 2630 const char *lts, *rts; 2631 *(lst == FUNC ? <s : &rts) = "function pointer"; 2632 *(lst == VOID ? <s : &rts) = "'void *'"; 2633 2634 switch (op) { 2635 case INIT: 2636 case RETURN: 2637 /* ANSI C forbids conversion of %s to %s */ 2638 warning(303, rts, lts); 2639 break; 2640 case FARG: 2641 /* ANSI C forbids conversion of %s to %s, arg #%d */ 2642 warning(304, rts, lts, arg); 2643 break; 2644 default: 2645 /* ANSI C forbids conversion of %s to %s, op %s */ 2646 warning(305, rts, lts, op_name(op)); 2647 break; 2648 } 2649 } 2650 2651 static bool 2652 is_direct_function_call(const tnode_t *tn, const char **out_name) 2653 { 2654 2655 if (!(tn->tn_op == CALL && 2656 tn->tn_left->tn_op == ADDR && 2657 tn->tn_left->tn_left->tn_op == NAME)) 2658 return false; 2659 2660 *out_name = tn->tn_left->tn_left->tn_sym->s_name; 2661 return true; 2662 } 2663 2664 static bool 2665 is_unconst_function(const char *name) 2666 { 2667 2668 return strcmp(name, "memchr") == 0 || 2669 strcmp(name, "strchr") == 0 || 2670 strcmp(name, "strpbrk") == 0 || 2671 strcmp(name, "strrchr") == 0 || 2672 strcmp(name, "strstr") == 0; 2673 } 2674 2675 static bool 2676 is_const_char_pointer(const tnode_t *tn) 2677 { 2678 /* 2679 * For traditional reasons, C99 6.4.5p5 defines that string literals 2680 * have type 'char[]'. They are often implicitly converted to 2681 * 'char *', for example when they are passed as function arguments. 2682 * 2683 * C99 6.4.5p6 further defines that modifying a string that is 2684 * constructed from a string literal invokes undefined behavior. 2685 * 2686 * Out of these reasons, string literals are treated as 'effectively 2687 * const' here. 2688 */ 2689 if (tn->tn_op == CVT && 2690 tn->tn_left->tn_op == ADDR && 2691 tn->tn_left->tn_left->tn_op == STRING) 2692 return true; 2693 2694 const type_t *tp = before_conversion(tn)->tn_type; 2695 return tp->t_tspec == PTR && 2696 tp->t_subt->t_tspec == CHAR && 2697 tp->t_subt->t_const; 2698 } 2699 2700 static bool 2701 is_first_arg_const_char_pointer(const tnode_t *tn) 2702 { 2703 const tnode_t *an = tn->tn_right; 2704 if (an == NULL) 2705 return false; 2706 2707 while (an->tn_right != NULL) 2708 an = an->tn_right; 2709 return is_const_char_pointer(an->tn_left); 2710 } 2711 2712 static bool 2713 is_const_pointer(const tnode_t *tn) 2714 { 2715 const type_t *tp = before_conversion(tn)->tn_type; 2716 return tp->t_tspec == PTR && tp->t_subt->t_const; 2717 } 2718 2719 static bool 2720 is_second_arg_const_pointer(const tnode_t *tn) 2721 { 2722 const tnode_t *an = tn->tn_right; 2723 if (an == NULL || an->tn_right == NULL) 2724 return false; 2725 2726 while (an->tn_right->tn_right != NULL) 2727 an = an->tn_right; 2728 return is_const_pointer(an->tn_left); 2729 } 2730 2731 static void 2732 check_unconst_function(const type_t *lstp, const tnode_t *rn) 2733 { 2734 const char *function_name; 2735 2736 if (lstp->t_tspec == CHAR && !lstp->t_const && 2737 is_direct_function_call(rn, &function_name) && 2738 is_unconst_function(function_name) && 2739 is_first_arg_const_char_pointer(rn)) { 2740 /* call to '%s' effectively discards 'const' from argument */ 2741 warning(346, function_name); 2742 } 2743 2744 if (!lstp->t_const && 2745 is_direct_function_call(rn, &function_name) && 2746 strcmp(function_name, "bsearch") == 0 && 2747 is_second_arg_const_pointer(rn)) { 2748 /* call to '%s' effectively discards 'const' from argument */ 2749 warning(346, function_name); 2750 } 2751 } 2752 2753 static bool 2754 check_assign_void_pointer_compat(op_t op, int arg, 2755 const type_t *const ltp, tspec_t const lt, 2756 const type_t *const lstp, tspec_t const lst, 2757 const tnode_t *const rn, 2758 const type_t *const rtp, tspec_t const rt, 2759 const type_t *const rstp, tspec_t const rst) 2760 { 2761 if (!(lt == PTR && rt == PTR && (lst == VOID || rst == VOID || 2762 types_compatible(lstp, rstp, 2763 true, false, NULL)))) 2764 return false; 2765 2766 /* compatible pointer types (qualifiers ignored) */ 2767 if (allow_c90 && 2768 ((!lstp->t_const && rstp->t_const) || 2769 (!lstp->t_volatile && rstp->t_volatile))) { 2770 /* left side has not all qualifiers of right */ 2771 switch (op) { 2772 case INIT: 2773 case RETURN: 2774 /* incompatible pointer types to '%s' and '%s' */ 2775 warning(182, type_name(lstp), type_name(rstp)); 2776 break; 2777 case FARG: 2778 /* converting '%s' to incompatible '%s' ... */ 2779 warning(153, 2780 type_name(rtp), type_name(ltp), arg); 2781 break; 2782 default: 2783 /* operands of '%s' have incompatible pointer ... */ 2784 warning(128, op_name(op), 2785 type_name(lstp), type_name(rstp)); 2786 break; 2787 } 2788 } 2789 2790 if (allow_c90) 2791 check_unconst_function(lstp, rn); 2792 2793 return true; 2794 } 2795 2796 static bool 2797 check_assign_pointer_integer(op_t op, int arg, 2798 const type_t *const ltp, tspec_t const lt, 2799 const type_t *const rtp, tspec_t const rt) 2800 { 2801 2802 if (!((lt == PTR && is_integer(rt)) || (is_integer(lt) && rt == PTR))) 2803 return false; 2804 2805 const char *lx = lt == PTR ? "pointer" : "integer"; 2806 const char *rx = rt == PTR ? "pointer" : "integer"; 2807 2808 switch (op) { 2809 case INIT: 2810 case RETURN: 2811 /* illegal combination of %s '%s' and %s '%s' */ 2812 warning(183, lx, type_name(ltp), rx, type_name(rtp)); 2813 break; 2814 case FARG: 2815 /* illegal combination of %s '%s' and %s '%s', arg #%d */ 2816 warning(154, 2817 lx, type_name(ltp), rx, type_name(rtp), arg); 2818 break; 2819 default: 2820 /* illegal combination of %s '%s' and %s '%s', op '%s' */ 2821 warning(123, 2822 lx, type_name(ltp), rx, type_name(rtp), op_name(op)); 2823 break; 2824 } 2825 return true; 2826 } 2827 2828 static bool 2829 check_assign_pointer(op_t op, int arg, 2830 const type_t *ltp, tspec_t lt, 2831 const type_t *rtp, tspec_t rt) 2832 { 2833 if (!(lt == PTR && rt == PTR)) 2834 return false; 2835 2836 switch (op) { 2837 case RETURN: 2838 warn_incompatible_pointers(NULL, ltp, rtp); 2839 break; 2840 case FARG: 2841 /* converting '%s' to incompatible '%s' for ... */ 2842 warning(153, type_name(rtp), type_name(ltp), arg); 2843 break; 2844 default: 2845 warn_incompatible_pointers(&modtab[op], ltp, rtp); 2846 break; 2847 } 2848 return true; 2849 } 2850 2851 static void 2852 warn_assign(op_t op, int arg, 2853 const type_t *ltp, tspec_t lt, 2854 const type_t *rtp, tspec_t rt) 2855 { 2856 switch (op) { 2857 case INIT: 2858 /* cannot initialize '%s' from '%s' */ 2859 error(185, type_name(ltp), type_name(rtp)); 2860 break; 2861 case RETURN: 2862 /* function has return type '%s' but returns '%s' */ 2863 error(211, type_name(ltp), type_name(rtp)); 2864 break; 2865 case FARG: 2866 /* passing '%s' to incompatible '%s', arg #%d */ 2867 warning(155, type_name(rtp), type_name(ltp), arg); 2868 break; 2869 default: 2870 warn_incompatible_types(op, ltp, lt, rtp, rt); 2871 break; 2872 } 2873 } 2874 2875 /* 2876 * Checks type compatibility for ASSIGN, INIT, FARG and RETURN 2877 * and prints warnings/errors if necessary. 2878 * Returns whether the types are (almost) compatible. 2879 */ 2880 static bool 2881 check_assign_types_compatible(op_t op, int arg, 2882 const tnode_t *ln, const tnode_t *rn) 2883 { 2884 tspec_t lt, rt, lst = NO_TSPEC, rst = NO_TSPEC; 2885 type_t *ltp, *rtp, *lstp = NULL, *rstp = NULL; 2886 2887 if ((lt = (ltp = ln->tn_type)->t_tspec) == PTR) 2888 lst = (lstp = ltp->t_subt)->t_tspec; 2889 if ((rt = (rtp = rn->tn_type)->t_tspec) == PTR) 2890 rst = (rstp = rtp->t_subt)->t_tspec; 2891 2892 if (lt == BOOL && is_scalar(rt)) /* C99 6.3.1.2 */ 2893 return true; 2894 2895 if (is_arithmetic(lt) && (is_arithmetic(rt) || rt == BOOL)) 2896 return true; 2897 2898 if (is_struct_or_union(lt) && is_struct_or_union(rt)) 2899 /* both are struct or union */ 2900 return ltp->t_sou == rtp->t_sou; 2901 2902 /* a null pointer may be assigned to any pointer */ 2903 if (lt == PTR && is_null_pointer(rn)) { 2904 if (is_integer(rn->tn_type->t_tspec)) 2905 /* implicit conversion from integer 0 to pointer ... */ 2906 query_message(15, type_name(ltp)); 2907 return true; 2908 } 2909 2910 check_assign_void_pointer(op, arg, lt, lst, rt, rst); 2911 2912 if (check_assign_void_pointer_compat(op, arg, 2913 ltp, lt, lstp, lst, rn, rtp, rt, rstp, rst)) 2914 return true; 2915 2916 if (check_assign_pointer_integer(op, arg, ltp, lt, rtp, rt)) 2917 return true; 2918 2919 if (check_assign_pointer(op, arg, ltp, lt, rtp, rt)) 2920 return true; 2921 2922 warn_assign(op, arg, ltp, lt, rtp, rt); 2923 return false; 2924 } 2925 2926 static bool 2927 has_side_effect(const tnode_t *tn) /* NOLINT(misc-no-recursion) */ 2928 { 2929 op_t op = tn->tn_op; 2930 2931 if (modtab[op].m_has_side_effect) 2932 return true; 2933 2934 if (op == CVT && tn->tn_type->t_tspec == VOID) 2935 return has_side_effect(tn->tn_left); 2936 2937 /* XXX: Why not has_side_effect(tn->tn_left) as well? */ 2938 if (op == LOGAND || op == LOGOR) 2939 return has_side_effect(tn->tn_right); 2940 2941 /* XXX: Why not has_side_effect(tn->tn_left) as well? */ 2942 if (op == QUEST) 2943 return has_side_effect(tn->tn_right); 2944 2945 if (op == COLON || op == COMMA) { 2946 return has_side_effect(tn->tn_left) || 2947 has_side_effect(tn->tn_right); 2948 } 2949 2950 return false; 2951 } 2952 2953 static bool 2954 is_void_cast(const tnode_t *tn) 2955 { 2956 2957 return tn->tn_op == CVT && tn->tn_cast && 2958 tn->tn_type->t_tspec == VOID; 2959 } 2960 2961 static bool 2962 is_local_symbol(const tnode_t *tn) 2963 { 2964 2965 return tn->tn_op == LOAD && 2966 tn->tn_left->tn_op == NAME && 2967 tn->tn_left->tn_sym->s_scl == AUTO; 2968 } 2969 2970 static bool 2971 is_int_constant_zero(const tnode_t *tn) 2972 { 2973 2974 return tn->tn_op == CON && 2975 tn->tn_type->t_tspec == INT && 2976 tn->tn_val.u.integer == 0; 2977 } 2978 2979 static void 2980 check_null_effect(const tnode_t *tn) 2981 { 2982 2983 if (hflag && 2984 !has_side_effect(tn) && 2985 !(is_void_cast(tn) && is_local_symbol(tn->tn_left)) && 2986 !(is_void_cast(tn) && is_int_constant_zero(tn->tn_left))) { 2987 /* expression has null effect */ 2988 warning(129); 2989 } 2990 } 2991 2992 /* 2993 * Check the types for specific operators and type combinations. 2994 * 2995 * At this point, the operands already conform to the type requirements of 2996 * the operator, such as being integer, floating or scalar. 2997 */ 2998 static bool 2999 typeok_op(op_t op, const mod_t *mp, int arg, 3000 const tnode_t *ln, const type_t *ltp, tspec_t lt, 3001 const tnode_t *rn, const type_t *rtp, tspec_t rt) 3002 { 3003 switch (op) { 3004 case ARROW: 3005 return typeok_arrow(lt); 3006 case POINT: 3007 return typeok_point(ln, ltp, lt); 3008 case INCBEF: 3009 case DECBEF: 3010 case INCAFT: 3011 case DECAFT: 3012 return typeok_incdec(op, ln, ltp); 3013 case INDIR: 3014 return typeok_indir(ltp, lt); 3015 case ADDR: 3016 return typeok_address(mp, ln, ltp, lt); 3017 case PLUS: 3018 return typeok_plus(op, ltp, lt, rtp, rt); 3019 case MINUS: 3020 return typeok_minus(op, ltp, lt, rtp, rt); 3021 case SHL: 3022 typeok_shl(mp, lt, rt); 3023 goto shift; 3024 case SHR: 3025 typeok_shr(mp, ln, lt, rn, rt); 3026 shift: 3027 typeok_shift(ltp, lt, rn, rt); 3028 break; 3029 case LT: 3030 case LE: 3031 case GT: 3032 case GE: 3033 compare: 3034 return typeok_compare(op, ln, ltp, lt, rn, rtp, rt); 3035 case EQ: 3036 case NE: 3037 if (is_typeok_eq(ln, lt, rn, rt)) 3038 break; 3039 goto compare; 3040 case QUEST: 3041 return typeok_quest(lt, rn); 3042 case COLON: 3043 return typeok_colon(mp, ln, ltp, lt, rn, rtp, rt); 3044 case ASSIGN: 3045 case INIT: 3046 case FARG: 3047 case RETURN: 3048 if (!check_assign_types_compatible(op, arg, ln, rn)) 3049 return false; 3050 goto assign; 3051 case MULASS: 3052 case DIVASS: 3053 case MODASS: 3054 goto assign; 3055 case ADDASS: 3056 case SUBASS: 3057 if ((lt == PTR && !is_integer(rt)) || rt == PTR) { 3058 warn_incompatible_types(op, ltp, lt, rtp, rt); 3059 return false; 3060 } 3061 goto assign; 3062 case SHLASS: 3063 goto assign; 3064 case SHRASS: 3065 if (pflag && !is_uinteger(lt) && 3066 !(!allow_c90 && is_uinteger(rt))) { 3067 /* bitwise '%s' on signed value possibly nonportable */ 3068 warning(117, mp->m_name); 3069 } 3070 goto assign; 3071 case ANDASS: 3072 case XORASS: 3073 case ORASS: 3074 assign: 3075 return typeok_assign(op, ln, ltp, lt); 3076 case COMMA: 3077 if (!modtab[ln->tn_op].m_has_side_effect) 3078 check_null_effect(ln); 3079 break; 3080 default: 3081 break; 3082 } 3083 return true; 3084 } 3085 3086 /* Prints a warning if a strange operator is used on an enum type. */ 3087 static void 3088 check_bad_enum_operation(op_t op, const tnode_t *ln, const tnode_t *rn) 3089 { 3090 3091 if (!eflag) 3092 return; 3093 3094 /* Allow enum in array indices. */ 3095 if (op == PLUS && 3096 ((ln->tn_type->t_is_enum && rn->tn_type->t_tspec == PTR) || 3097 (rn->tn_type->t_is_enum && ln->tn_type->t_tspec == PTR))) { 3098 return; 3099 } 3100 3101 /* dubious operation '%s' on enum */ 3102 warning(241, op_name(op)); 3103 } 3104 3105 /* Prints a warning if an operator is applied to two different enum types. */ 3106 static void 3107 check_enum_type_mismatch(op_t op, int arg, const tnode_t *ln, const tnode_t *rn) 3108 { 3109 const mod_t *mp = &modtab[op]; 3110 3111 if (ln->tn_type->t_enum != rn->tn_type->t_enum) { 3112 switch (op) { 3113 case INIT: 3114 /* enum type mismatch between '%s' and '%s' in ... */ 3115 warning(210, 3116 type_name(ln->tn_type), type_name(rn->tn_type)); 3117 break; 3118 case FARG: 3119 /* function expects '%s', passing '%s' for arg #%d */ 3120 warning(156, 3121 type_name(ln->tn_type), type_name(rn->tn_type), 3122 arg); 3123 break; 3124 case RETURN: 3125 /* function has return type '%s' but returns '%s' */ 3126 warning(211, 3127 type_name(ln->tn_type), type_name(rn->tn_type)); 3128 break; 3129 default: 3130 /* enum type mismatch: '%s' '%s' '%s' */ 3131 warning(130, type_name(ln->tn_type), mp->m_name, 3132 type_name(rn->tn_type)); 3133 break; 3134 } 3135 } else if (Pflag && eflag && mp->m_comparison && op != EQ && op != NE) 3136 /* operator '%s' assumes that '%s' is ordered */ 3137 warning(243, mp->m_name, type_name(ln->tn_type)); 3138 } 3139 3140 /* Prints a warning if the operands mix between enum and integer. */ 3141 static void 3142 check_enum_int_mismatch(op_t op, int arg, const tnode_t *ln, const tnode_t *rn) 3143 { 3144 3145 if (!eflag) 3146 return; 3147 3148 switch (op) { 3149 case INIT: 3150 /* 3151 * Initialization with 0 is allowed. Otherwise, all implicit 3152 * initializations would need to be warned upon as well. 3153 */ 3154 if (!rn->tn_type->t_is_enum && rn->tn_op == CON && 3155 is_integer(rn->tn_type->t_tspec) && 3156 rn->tn_val.u.integer == 0) { 3157 return; 3158 } 3159 /* initialization of '%s' with '%s' */ 3160 warning(277, type_name(ln->tn_type), type_name(rn->tn_type)); 3161 break; 3162 case FARG: 3163 /* combination of '%s' and '%s', arg #%d */ 3164 warning(278, 3165 type_name(ln->tn_type), type_name(rn->tn_type), arg); 3166 break; 3167 case RETURN: 3168 /* combination of '%s' and '%s' in return */ 3169 warning(279, type_name(ln->tn_type), type_name(rn->tn_type)); 3170 break; 3171 default: 3172 /* combination of '%s' and '%s', op '%s' */ 3173 warning(242, type_name(ln->tn_type), type_name(rn->tn_type), 3174 op_name(op)); 3175 break; 3176 } 3177 } 3178 3179 static void 3180 typeok_enum(op_t op, const mod_t *mp, int arg, 3181 const tnode_t *ln, const type_t *ltp, 3182 const tnode_t *rn, const type_t *rtp) 3183 { 3184 if (mp->m_bad_on_enum && 3185 (ltp->t_is_enum || (mp->m_binary && rtp->t_is_enum))) { 3186 check_bad_enum_operation(op, ln, rn); 3187 } else if (mp->m_valid_on_enum && 3188 (ltp->t_is_enum && rtp != NULL && rtp->t_is_enum)) { 3189 check_enum_type_mismatch(op, arg, ln, rn); 3190 } else if (mp->m_valid_on_enum && 3191 (ltp->t_is_enum || (rtp != NULL && rtp->t_is_enum))) { 3192 check_enum_int_mismatch(op, arg, ln, rn); 3193 } 3194 } 3195 3196 /* Perform most type checks. Return whether the types are ok. */ 3197 bool 3198 typeok(op_t op, int arg, const tnode_t *ln, const tnode_t *rn) 3199 { 3200 3201 const mod_t *mp = &modtab[op]; 3202 3203 type_t *ltp = ln->tn_type; 3204 tspec_t lt = ltp->t_tspec; 3205 3206 type_t *rtp = mp->m_binary ? rn->tn_type : NULL; 3207 tspec_t rt = mp->m_binary ? rtp->t_tspec : NO_TSPEC; 3208 3209 if (Tflag && !typeok_scalar_strict_bool(op, mp, arg, ln, rn)) 3210 return false; 3211 if (!typeok_scalar(op, mp, ltp, lt, rtp, rt)) 3212 return false; 3213 3214 if (!typeok_op(op, mp, arg, ln, ltp, lt, rn, rtp, rt)) 3215 return false; 3216 3217 typeok_enum(op, mp, arg, ln, ltp, rn, rtp); 3218 return true; 3219 } 3220 3221 /* In traditional C, keep unsigned and promote FLOAT to DOUBLE. */ 3222 static tspec_t 3223 promote_trad(tspec_t t) 3224 { 3225 3226 if (t == UCHAR || t == USHORT) 3227 return UINT; 3228 if (t == CHAR || t == SCHAR || t == SHORT) 3229 return INT; 3230 if (t == FLOAT) 3231 return DOUBLE; 3232 if (t == ENUM) 3233 return INT; 3234 return t; 3235 } 3236 3237 /* 3238 * C99 6.3.1.1p2 requires for types with lower rank than int that "If an int 3239 * can represent all the values of the original type, the value is converted 3240 * to an int; otherwise it is converted to an unsigned int", and that "All 3241 * other types are unchanged by the integer promotions". 3242 */ 3243 static tspec_t 3244 promote_c90(const tnode_t *tn, tspec_t t, bool farg) 3245 { 3246 if (tn->tn_type->t_bitfield) { 3247 unsigned int width = tn->tn_type->t_bit_field_width; 3248 unsigned int int_width = size_in_bits(INT); 3249 // XXX: What about _Bool bit-fields, since C99? 3250 if (width < int_width) 3251 return INT; 3252 if (width == int_width) 3253 return is_uinteger(t) ? UINT : INT; 3254 return t; 3255 } 3256 3257 if (t == CHAR || t == SCHAR) 3258 return INT; 3259 if (t == UCHAR) 3260 return size_in_bits(CHAR) < size_in_bits(INT) ? INT : UINT; 3261 if (t == SHORT) 3262 return INT; 3263 if (t == USHORT) 3264 return size_in_bits(SHORT) < size_in_bits(INT) ? INT : UINT; 3265 if (t == ENUM) 3266 return INT; 3267 if (farg && t == FLOAT) 3268 return DOUBLE; 3269 return t; 3270 } 3271 3272 /* 3273 * Performs the "integer promotions" (C99 6.3.1.1p2), which convert small 3274 * integer types to either int or unsigned int. 3275 * 3276 * If allow_c90 is unset or the operand is a function argument with no type 3277 * information (no prototype or variable # of args), converts float to double. 3278 */ 3279 tnode_t * 3280 promote(op_t op, bool farg, tnode_t *tn) 3281 { 3282 3283 tspec_t ot = tn->tn_type->t_tspec; 3284 if (!is_arithmetic(ot)) 3285 return tn; 3286 3287 tspec_t nt = allow_c90 ? promote_c90(tn, ot, farg) : promote_trad(ot); 3288 if (nt == ot) 3289 return tn; 3290 3291 type_t *ntp = expr_dup_type(tn->tn_type); 3292 ntp->t_tspec = nt; 3293 /* 3294 * Keep t_is_enum even though t_tspec gets converted from 3295 * ENUM to INT, so we are later able to check compatibility 3296 * of enum types. 3297 */ 3298 return convert(op, 0, ntp, tn); 3299 } 3300 3301 static void 3302 convert_integer_from_floating(op_t op, const type_t *tp, const tnode_t *tn) 3303 { 3304 3305 if (op == CVT) 3306 /* cast from floating point '%s' to integer '%s' */ 3307 query_message(2, type_name(tn->tn_type), type_name(tp)); 3308 else 3309 /* implicit conversion from floating point '%s' to ... */ 3310 query_message(1, type_name(tn->tn_type), type_name(tp)); 3311 } 3312 3313 static bool 3314 should_warn_about_prototype_conversion(tspec_t nt, 3315 tspec_t ot, const tnode_t *ptn) 3316 { 3317 3318 if (nt == ot) 3319 return false; 3320 3321 if (nt == ENUM && ot == INT) 3322 return false; 3323 3324 if (is_floating(nt) != is_floating(ot) || 3325 portable_rank_cmp(nt, ot) != 0) { 3326 /* representation and/or width change */ 3327 if (!is_integer(ot)) 3328 return true; 3329 /* 3330 * XXX: Investigate whether this rule makes sense; see 3331 * tests/usr.bin/xlint/lint1/platform_long.c. 3332 */ 3333 return portable_rank_cmp(ot, INT) > 0; 3334 } 3335 3336 if (!hflag) 3337 return false; 3338 3339 /* 3340 * If the types differ only in sign and the argument has the same 3341 * representation in both types, print no warning. 3342 */ 3343 if (ptn->tn_op == CON && is_integer(nt) && 3344 signed_type(nt) == signed_type(ot) && 3345 !msb(ptn->tn_val.u.integer, ot)) 3346 return false; 3347 3348 return true; 3349 } 3350 3351 /* 3352 * Warn if a prototype causes a type conversion that is different from what 3353 * would happen to the same argument in the absence of a prototype. This 3354 * check is intended for code that needs to stay compatible with pre-C90 C. 3355 * 3356 * Errors/warnings about illegal type combinations are already printed 3357 * in check_assign_types_compatible(). 3358 */ 3359 static void 3360 check_prototype_conversion(int arg, tspec_t nt, tspec_t ot, type_t *tp, 3361 tnode_t *tn) 3362 { 3363 3364 if (!is_arithmetic(nt) || !is_arithmetic(ot)) 3365 return; 3366 3367 /* 3368 * If the type of the formal parameter is char/short, a warning 3369 * would be useless, because functions declared the old style 3370 * can't expect char/short arguments. 3371 */ 3372 if (nt == CHAR || nt == SCHAR || nt == UCHAR || 3373 nt == SHORT || nt == USHORT) 3374 return; 3375 3376 /* apply the default promotion */ 3377 tnode_t *ptn = promote(NOOP, true, tn); 3378 ot = ptn->tn_type->t_tspec; 3379 3380 if (should_warn_about_prototype_conversion(nt, ot, ptn)) { 3381 /* argument %d is converted from '%s' to '%s' ... */ 3382 warning(259, arg, type_name(tn->tn_type), type_name(tp)); 3383 } 3384 } 3385 3386 /* 3387 * When converting a large integer type to a small integer type, in some 3388 * cases the value of the actual expression is further restricted than the 3389 * type bounds, such as in (expr & 0xFF) or (expr % 100) or (expr >> 24). 3390 */ 3391 static bool 3392 can_represent(const type_t *tp, const tnode_t *tn) 3393 { 3394 3395 debug_step("%s: type '%s'", __func__, type_name(tp)); 3396 debug_node(tn); 3397 3398 uint64_t nmask = value_bits(width_in_bits(tp)); 3399 if (!is_uinteger(tp->t_tspec)) 3400 nmask >>= 1; 3401 3402 integer_constraints c = ic_expr(tn); 3403 if ((~c.bclr & ~nmask) == 0) 3404 return true; 3405 3406 integer_constraints tpc = ic_any(tp); 3407 if (is_uinteger(tp->t_tspec) 3408 ? tpc.umin <= c.umin && tpc.umax >= c.umax 3409 : tpc.smin <= c.smin && tpc.smax >= c.smax) 3410 return true; 3411 3412 return false; 3413 } 3414 3415 static void 3416 convert_integer_from_integer(op_t op, int arg, tspec_t nt, tspec_t ot, 3417 type_t *tp, tnode_t *tn) 3418 { 3419 3420 if (tn->tn_op == CON) 3421 return; 3422 3423 if (op == CVT) 3424 return; 3425 3426 if (Pflag && pflag && aflag > 0 && 3427 portable_rank_cmp(nt, ot) > 0 && 3428 is_uinteger(nt) != is_uinteger(ot)) { 3429 if (op == FARG) { 3430 /* conversion to '%s' may sign-extend ... */ 3431 warning(297, type_name(tp), arg); 3432 } else { 3433 /* conversion to '%s' may sign-extend ... */ 3434 warning(131, type_name(tp)); 3435 } 3436 } 3437 3438 if (Pflag && portable_rank_cmp(nt, ot) > 0 && 3439 (tn->tn_op == PLUS || tn->tn_op == MINUS || tn->tn_op == MULT || 3440 tn->tn_op == SHL)) { 3441 /* suggest cast from '%s' to '%s' on op '%s' to ... */ 3442 warning(324, type_name(gettyp(ot)), type_name(tp), 3443 op_name(tn->tn_op)); 3444 } 3445 3446 if (aflag > 0 && 3447 portable_rank_cmp(nt, ot) < 0 && 3448 (portable_rank_cmp(ot, LONG) >= 0 || aflag > 1) && 3449 // XXX: The portable_rank_cmp above aims at portable mode, 3450 // independent of the current platform, while can_represent acts 3451 // on the actual type sizes from the current platform. This mix 3452 // is inconsistent, but anything else would make the exact 3453 // conditions too complicated to grasp. 3454 !can_represent(tp, tn)) { 3455 if (op == FARG) { 3456 /* conversion from '%s' to '%s' may lose ... */ 3457 warning(298, 3458 type_name(tn->tn_type), type_name(tp), arg); 3459 } else { 3460 /* conversion from '%s' to '%s' may lose accuracy */ 3461 warning(132, 3462 type_name(tn->tn_type), type_name(tp)); 3463 } 3464 } 3465 3466 if (any_query_enabled && is_uinteger(nt) != is_uinteger(ot)) 3467 /* implicit conversion changes sign from '%s' to '%s' */ 3468 query_message(3, type_name(tn->tn_type), type_name(tp)); 3469 } 3470 3471 static void 3472 convert_integer_from_pointer(op_t op, tspec_t nt, type_t *tp, tnode_t *tn) 3473 { 3474 3475 if (tn->tn_op == CON) 3476 return; 3477 if (op != CVT) 3478 return; /* We already got an error. */ 3479 if (portable_rank_cmp(nt, PTR) >= 0) 3480 return; 3481 3482 if (pflag && size_in_bits(nt) >= size_in_bits(PTR)) { 3483 /* conversion of pointer to '%s' may lose bits */ 3484 warning(134, type_name(tp)); 3485 } else { 3486 /* conversion of pointer to '%s' loses bits */ 3487 warning(133, type_name(tp)); 3488 } 3489 } 3490 3491 static bool 3492 struct_starts_with(const type_t *struct_tp, const type_t *member_tp) 3493 { 3494 3495 return struct_tp->t_sou->sou_first_member != NULL && 3496 types_compatible(struct_tp->t_sou->sou_first_member->s_type, 3497 member_tp, true, false, NULL); 3498 } 3499 3500 static bool 3501 is_byte_array(const type_t *tp) 3502 { 3503 3504 return tp->t_tspec == ARRAY && 3505 (tp->t_subt->t_tspec == CHAR || tp->t_subt->t_tspec == UCHAR); 3506 } 3507 3508 static bool 3509 union_contains(const type_t *utp, const type_t *mtp) 3510 { 3511 for (const sym_t *mem = utp->t_sou->sou_first_member; 3512 mem != NULL; mem = mem->s_next) { 3513 if (types_compatible(mem->s_type, mtp, true, false, NULL)) 3514 return true; 3515 } 3516 return false; 3517 } 3518 3519 static bool 3520 should_warn_about_pointer_cast(const type_t *nstp, tspec_t nst, 3521 const type_t *ostp, tspec_t ost) 3522 { 3523 3524 while (nst == ARRAY) 3525 nstp = nstp->t_subt, nst = nstp->t_tspec; 3526 while (ost == ARRAY) 3527 ostp = ostp->t_subt, ost = ostp->t_tspec; 3528 3529 if (nst == STRUCT && ost == STRUCT && 3530 (struct_starts_with(nstp, ostp) || 3531 struct_starts_with(ostp, nstp))) 3532 return false; 3533 3534 if (is_incomplete(nstp) || is_incomplete(ostp)) 3535 return false; 3536 3537 if (nst == CHAR || nst == UCHAR) 3538 return false; /* for the sake of traditional C code */ 3539 if (ost == CHAR || ost == UCHAR) 3540 return false; /* for the sake of traditional C code */ 3541 3542 /* Allow cast between pointers to sockaddr variants. */ 3543 if (nst == STRUCT && ost == STRUCT) { 3544 const sym_t *nmem = nstp->t_sou->sou_first_member; 3545 const sym_t *omem = ostp->t_sou->sou_first_member; 3546 while (nmem != NULL && omem != NULL && 3547 types_compatible(nmem->s_type, omem->s_type, 3548 true, false, NULL)) 3549 nmem = nmem->s_next, omem = omem->s_next; 3550 if (nmem != NULL && is_byte_array(nmem->s_type)) 3551 return false; 3552 if (omem != NULL && is_byte_array(omem->s_type)) 3553 return false; 3554 if (nmem == NULL && omem == NULL) 3555 return false; 3556 } 3557 3558 if (nst == UNION || ost == UNION) { 3559 const type_t *union_tp = nst == UNION ? nstp : ostp; 3560 const type_t *other_tp = nst == UNION ? ostp : nstp; 3561 if (union_contains(union_tp, other_tp)) 3562 return false; 3563 } 3564 3565 if (is_struct_or_union(nst) && is_struct_or_union(ost)) 3566 return nstp->t_sou != ostp->t_sou; 3567 3568 enum rank_kind rk1 = type_properties(nst)->tt_rank_kind; 3569 enum rank_kind rk2 = type_properties(ost)->tt_rank_kind; 3570 if (rk1 != rk2 || rk1 == RK_NONE) 3571 return true; 3572 3573 return portable_rank_cmp(nst, ost) != 0; 3574 } 3575 3576 static void 3577 convert_pointer_from_pointer(type_t *ntp, tnode_t *tn) 3578 { 3579 const type_t *nstp = ntp->t_subt; 3580 const type_t *otp = tn->tn_type; 3581 const type_t *ostp = otp->t_subt; 3582 tspec_t nst = nstp->t_tspec; 3583 tspec_t ost = ostp->t_tspec; 3584 3585 if (nst == VOID || ost == VOID) { 3586 /* TODO: C99 behaves like C90 here. */ 3587 if ((!allow_trad && !allow_c99) && (nst == FUNC || ost == FUNC)) { 3588 const char *nts, *ots; 3589 /* null pointers are already handled in convert() */ 3590 *(nst == FUNC ? &nts : &ots) = "function pointer"; 3591 *(nst == VOID ? &nts : &ots) = "'void *'"; 3592 /* ANSI C forbids conversion of %s to %s */ 3593 warning(303, ots, nts); 3594 } 3595 return; 3596 } 3597 if (nst == FUNC && ost == FUNC) 3598 return; 3599 if (nst == FUNC || ost == FUNC) { 3600 /* converting '%s' to '%s' is questionable */ 3601 warning(229, type_name(otp), type_name(ntp)); 3602 return; 3603 } 3604 3605 if (hflag && alignment_in_bits(nstp) > alignment_in_bits(ostp) && 3606 ost != CHAR && ost != UCHAR && 3607 !is_incomplete(ostp) && 3608 !(nst == UNION && union_contains(nstp, ostp))) { 3609 /* converting '%s' to '%s' increases alignment ... */ 3610 warning(135, type_name(otp), type_name(ntp), 3611 alignment_in_bits(ostp) / CHAR_SIZE, 3612 alignment_in_bits(nstp) / CHAR_SIZE); 3613 } 3614 3615 if (cflag && should_warn_about_pointer_cast(nstp, nst, ostp, ost)) { 3616 /* pointer cast from '%s' to '%s' may be troublesome */ 3617 warning(247, type_name(otp), type_name(ntp)); 3618 } 3619 } 3620 3621 /* 3622 * Insert a conversion operator, which converts the type of the node 3623 * to another given type. 3624 * 3625 * Possible values for 'op': 3626 * CVT a cast-expression 3627 * binary integer promotion for one of the operands, or a usual 3628 * arithmetic conversion 3629 * binary plain or compound assignments to bit-fields 3630 * FARG 'arg' is the number of the argument (used for warnings) 3631 * NOOP several other implicit conversions 3632 * ... 3633 */ 3634 tnode_t * 3635 convert(op_t op, int arg, type_t *tp, tnode_t *tn) 3636 { 3637 tspec_t nt = tp->t_tspec; 3638 tspec_t ot = tn->tn_type->t_tspec; 3639 3640 if (allow_trad && allow_c90 && op == FARG) 3641 check_prototype_conversion(arg, nt, ot, tp, tn); 3642 3643 if (nt == BOOL) { 3644 /* No further checks. */ 3645 3646 } else if (is_integer(nt)) { 3647 if (ot == BOOL) { 3648 /* No further checks. */ 3649 } else if (is_integer(ot)) 3650 convert_integer_from_integer(op, arg, nt, ot, tp, tn); 3651 else if (is_floating(ot)) 3652 convert_integer_from_floating(op, tp, tn); 3653 else if (ot == PTR) 3654 convert_integer_from_pointer(op, nt, tp, tn); 3655 3656 } else if (is_floating(nt)) { 3657 /* No further checks. */ 3658 3659 } else if (nt == PTR) { 3660 if (is_null_pointer(tn)) { 3661 /* a null pointer may be assigned to any pointer. */ 3662 } else if (ot == PTR && op == CVT) 3663 convert_pointer_from_pointer(tp, tn); 3664 } 3665 3666 tnode_t *ntn = expr_alloc_tnode(); 3667 ntn->tn_op = CVT; 3668 ntn->tn_type = tp; 3669 ntn->tn_cast = op == CVT; 3670 ntn->tn_sys |= tn->tn_sys; 3671 ntn->tn_right = NULL; 3672 if (tn->tn_op != CON || nt == VOID) { 3673 ntn->tn_left = tn; 3674 } else { 3675 ntn->tn_op = CON; 3676 convert_constant(op, arg, ntn->tn_type, &ntn->tn_val, 3677 &tn->tn_val); 3678 } 3679 3680 return ntn; 3681 } 3682 3683 static void 3684 convert_constant_floating(op_t op, int arg, tspec_t ot, const type_t *tp, 3685 tspec_t nt, val_t *v, val_t *nv) 3686 { 3687 long double max = 0.0, min = 0.0; 3688 3689 switch (nt) { 3690 case CHAR: 3691 max = TARG_CHAR_MAX; min = TARG_CHAR_MIN; break; 3692 case UCHAR: 3693 max = TARG_UCHAR_MAX; min = 0; break; 3694 case SCHAR: 3695 max = TARG_SCHAR_MAX; min = TARG_SCHAR_MIN; break; 3696 case SHORT: 3697 max = TARG_SHRT_MAX; min = TARG_SHRT_MIN; break; 3698 case USHORT: 3699 max = TARG_USHRT_MAX; min = 0; break; 3700 case ENUM: 3701 case INT: 3702 max = TARG_INT_MAX; min = TARG_INT_MIN; break; 3703 case UINT: 3704 max = TARG_UINT_MAX; min = 0; break; 3705 case LONG: 3706 max = TARG_LONG_MAX; min = TARG_LONG_MIN; break; 3707 case ULONG: 3708 max = TARG_ULONG_MAX; min = 0; break; 3709 case LLONG: 3710 max = LLONG_MAX; min = LLONG_MIN; break; 3711 case ULLONG: 3712 max = ULLONG_MAX; min = 0; break; 3713 case FLOAT: 3714 case FCOMPLEX: 3715 max = FLT_MAX; min = -FLT_MAX; break; 3716 case DOUBLE: 3717 case DCOMPLEX: 3718 max = DBL_MAX; min = -DBL_MAX; break; 3719 case PTR: 3720 /* Already got an error because of float --> ptr */ 3721 case LDOUBLE: 3722 case LCOMPLEX: 3723 /* LINTED 248 */ 3724 max = LDBL_MAX; min = -max; break; 3725 default: 3726 lint_assert(/*CONSTCOND*/false); 3727 } 3728 if (v->u.floating > max || v->u.floating < min) { 3729 lint_assert(nt != LDOUBLE); 3730 if (op == FARG) { 3731 /* conversion of '%s' to '%s' is out of range, ... */ 3732 warning(295, 3733 type_name(gettyp(ot)), type_name(tp), arg); 3734 } else { 3735 /* conversion of '%s' to '%s' is out of range */ 3736 warning(119, type_name(gettyp(ot)), type_name(tp)); 3737 } 3738 v->u.floating = v->u.floating > 0 ? max : min; 3739 } 3740 3741 if (nt == FLOAT || nt == FCOMPLEX) 3742 nv->u.floating = (float)v->u.floating; 3743 else if (nt == DOUBLE || nt == DCOMPLEX) 3744 nv->u.floating = (double)v->u.floating; 3745 else if (nt == LDOUBLE || nt == LCOMPLEX) 3746 nv->u.floating = v->u.floating; 3747 else 3748 nv->u.integer = (int64_t)v->u.floating; 3749 } 3750 3751 static bool 3752 convert_constant_to_floating(tspec_t nt, val_t *nv, 3753 tspec_t ot, const val_t *v) 3754 { 3755 if (nt == FLOAT) { 3756 nv->u.floating = (ot == PTR || is_uinteger(ot)) ? 3757 (float)(uint64_t)v->u.integer : (float)v->u.integer; 3758 } else if (nt == DOUBLE) { 3759 nv->u.floating = (ot == PTR || is_uinteger(ot)) ? 3760 (double)(uint64_t)v->u.integer : (double)v->u.integer; 3761 } else if (nt == LDOUBLE) { 3762 nv->u.floating = (ot == PTR || is_uinteger(ot)) 3763 ? (long double)(uint64_t)v->u.integer 3764 : (long double)v->u.integer; 3765 } else 3766 return false; 3767 return true; 3768 } 3769 3770 /* 3771 * Print a warning if bits which were set are lost due to the conversion. 3772 * This can happen with operator ORASS only. 3773 */ 3774 static void 3775 convert_constant_check_range_bitor(size_t nsz, size_t osz, const val_t *v, 3776 uint64_t xmask, op_t op) 3777 { 3778 if (nsz < osz && (v->u.integer & xmask) != 0) { 3779 /* constant truncated by conversion, op '%s' */ 3780 warning(306, op_name(op)); 3781 } 3782 } 3783 3784 /* 3785 * Print a warning if additional bits are not all 1 3786 * and the most significant bit of the old value is 1, 3787 * or if at least one (but not all) removed bit was 0. 3788 */ 3789 static void 3790 convert_constant_check_range_bitand(size_t nsz, size_t osz, 3791 uint64_t xmask, const val_t *nv, 3792 tspec_t ot, const val_t *v, 3793 const type_t *tp, op_t op) 3794 { 3795 if (nsz > osz && 3796 (nv->u.integer & bit((unsigned int)(osz - 1))) != 0 && 3797 (nv->u.integer & xmask) != xmask) { 3798 /* extra bits set to 0 in conversion of '%s' to '%s', ... */ 3799 warning(309, type_name(gettyp(ot)), 3800 type_name(tp), op_name(op)); 3801 } else if (nsz < osz && 3802 (v->u.integer & xmask) != xmask && 3803 (v->u.integer & xmask) != 0) { 3804 /* constant truncated by conversion, op '%s' */ 3805 warning(306, op_name(op)); 3806 } 3807 } 3808 3809 static void 3810 convert_constant_check_range_signed(op_t op, int arg) 3811 { 3812 if (op == ASSIGN) { 3813 /* assignment of negative constant to unsigned type */ 3814 warning(164); 3815 } else if (op == INIT) { 3816 /* initialization of unsigned with negative constant */ 3817 warning(221); 3818 } else if (op == FARG) { 3819 /* conversion of negative constant to unsigned type, ... */ 3820 warning(296, arg); 3821 } else if (modtab[op].m_comparison) { 3822 /* handled by check_integer_comparison() */ 3823 } else { 3824 /* conversion of negative constant to unsigned type */ 3825 warning(222); 3826 } 3827 } 3828 3829 /* 3830 * Loss of significant bit(s). All truncated bits of unsigned types or all 3831 * truncated bits plus the msb of the target for signed types are considered 3832 * to be significant bits. Loss of significant bits means that at least one 3833 * of the bits was set in an unsigned type or that at least one but not all 3834 * of the bits was set in a signed type. Loss of significant bits means that 3835 * it is not possible, also not with necessary casts, to convert back to the 3836 * original type. An example for a necessary cast is: 3837 * char c; int i; c = 128; 3838 * i = c; ** yields -128 ** 3839 * i = (unsigned char)c; ** yields 128 ** 3840 */ 3841 static void 3842 warn_constant_check_range_truncated(op_t op, int arg, const type_t *tp, 3843 tspec_t ot) 3844 { 3845 if (op == ASSIGN && tp->t_bitfield) 3846 /* precision lost in bit-field assignment */ 3847 warning(166); 3848 else if (op == ASSIGN) 3849 /* constant truncated by assignment */ 3850 warning(165); 3851 else if (op == INIT && tp->t_bitfield) 3852 /* bit-field initializer does not fit */ 3853 warning(180); 3854 else if (op == INIT) 3855 /* initializer does not fit */ 3856 warning(178); 3857 else if (op == CASE) 3858 /* case label affected by conversion */ 3859 warning(196); 3860 else if (op == FARG) 3861 /* conversion of '%s' to '%s' is out of range, arg #%d */ 3862 warning(295, type_name(gettyp(ot)), type_name(tp), arg); 3863 else 3864 /* conversion of '%s' to '%s' is out of range */ 3865 warning(119, type_name(gettyp(ot)), type_name(tp)); 3866 } 3867 3868 static void 3869 warn_constant_check_range_loss(op_t op, int arg, const type_t *tp, 3870 tspec_t ot) 3871 { 3872 if (op == ASSIGN && tp->t_bitfield) 3873 /* precision lost in bit-field assignment */ 3874 warning(166); 3875 else if (op == INIT && tp->t_bitfield) 3876 /* bit-field initializer out of range */ 3877 warning(11); 3878 else if (op == CASE) 3879 /* case label affected by conversion */ 3880 warning(196); 3881 else if (op == FARG) 3882 /* conversion of '%s' to '%s' is out of range, arg #%d */ 3883 warning(295, type_name(gettyp(ot)), type_name(tp), arg); 3884 else 3885 /* conversion of '%s' to '%s' is out of range */ 3886 warning(119, type_name(gettyp(ot)), type_name(tp)); 3887 } 3888 3889 static void 3890 convert_constant_check_range(tspec_t ot, const type_t *tp, tspec_t nt, 3891 op_t op, int arg, const val_t *v, val_t *nv) 3892 { 3893 unsigned int obitsz, nbitsz; 3894 uint64_t xmask, xmsk1; 3895 3896 obitsz = size_in_bits(ot); 3897 nbitsz = tp->t_bitfield ? tp->t_bit_field_width : size_in_bits(nt); 3898 xmask = value_bits(nbitsz) ^ value_bits(obitsz); 3899 xmsk1 = value_bits(nbitsz) ^ value_bits(obitsz - 1); 3900 /* 3901 * For bitwise operations we are not interested in the arithmetic 3902 * value, but in the bits itself. 3903 */ 3904 if (op == ORASS || op == BITOR || op == BITXOR) { 3905 convert_constant_check_range_bitor( 3906 nbitsz, obitsz, v, xmask, op); 3907 } else if (op == ANDASS || op == BITAND) { 3908 convert_constant_check_range_bitand( 3909 nbitsz, obitsz, xmask, nv, ot, v, tp, op); 3910 } else if ((nt != PTR && is_uinteger(nt)) && 3911 (ot != PTR && !is_uinteger(ot)) && 3912 v->u.integer < 0) 3913 convert_constant_check_range_signed(op, arg); 3914 else if (nv->u.integer != v->u.integer && nbitsz <= obitsz && 3915 (v->u.integer & xmask) != 0 && 3916 (is_uinteger(ot) || (v->u.integer & xmsk1) != xmsk1)) 3917 warn_constant_check_range_truncated(op, arg, tp, ot); 3918 else if (nv->u.integer != v->u.integer) 3919 warn_constant_check_range_loss(op, arg, tp, ot); 3920 } 3921 3922 /* 3923 * Converts a typed constant to a constant of another type. 3924 * 3925 * op operator which requires conversion 3926 * arg if op is FARG, # of argument 3927 * tp type to which to convert the constant 3928 * nv new constant 3929 * v old constant 3930 */ 3931 void 3932 convert_constant(op_t op, int arg, const type_t *tp, val_t *nv, val_t *v) 3933 { 3934 /* 3935 * TODO: make 'v' const; the name of this function does not suggest 3936 * that it modifies 'v'. 3937 */ 3938 tspec_t ot = v->v_tspec; 3939 tspec_t nt = nv->v_tspec = tp->t_tspec; 3940 bool range_check = false; 3941 3942 if (nt == BOOL) { /* C99 6.3.1.2 */ 3943 nv->v_unsigned_since_c90 = false; 3944 nv->u.integer = is_nonzero_val(v) ? 1 : 0; 3945 return; 3946 } 3947 3948 if (ot == FLOAT || ot == DOUBLE || ot == LDOUBLE) 3949 convert_constant_floating(op, arg, ot, tp, nt, v, nv); 3950 else if (!convert_constant_to_floating(nt, nv, ot, v)) { 3951 range_check = true; /* Check for lost precision. */ 3952 nv->u.integer = v->u.integer; 3953 } 3954 3955 if (allow_trad && allow_c90 && v->v_unsigned_since_c90 && 3956 (is_floating(nt) || ( 3957 (is_integer(nt) && !is_uinteger(nt) && 3958 portable_rank_cmp(nt, ot) > 0)))) { 3959 /* ANSI C treats constant as unsigned */ 3960 warning(157); 3961 v->v_unsigned_since_c90 = false; 3962 } 3963 3964 if (is_integer(nt)) { 3965 nv->u.integer = convert_integer(nv->u.integer, nt, 3966 tp->t_bitfield ? tp->t_bit_field_width : size_in_bits(nt)); 3967 } 3968 3969 if (range_check && op != CVT) 3970 convert_constant_check_range(ot, tp, nt, op, arg, v, nv); 3971 } 3972 3973 /* 3974 * Create a constant node for sizeof. 3975 */ 3976 tnode_t * 3977 build_sizeof(const type_t *tp) 3978 { 3979 unsigned int size_in_bytes = type_size_in_bits(tp) / CHAR_SIZE; 3980 tnode_t *tn = build_integer_constant(SIZEOF_TSPEC, size_in_bytes); 3981 tn->tn_system_dependent = true; 3982 debug_step("build_sizeof '%s' = %u", type_name(tp), size_in_bytes); 3983 return tn; 3984 } 3985 3986 /* 3987 * Create a constant node for offsetof. 3988 */ 3989 /* ARGSUSED */ /* FIXME: See implementation comments. */ 3990 tnode_t * 3991 build_offsetof(const type_t *tp, const sym_t *sym) 3992 { 3993 3994 if (!is_struct_or_union(tp->t_tspec)) 3995 /* unacceptable operand of '%s' */ 3996 error(111, "offsetof"); 3997 3998 /* FIXME: Don't wrongly use the size of the whole type, use sym. */ 3999 unsigned int offset_in_bytes = type_size_in_bits(tp) / CHAR_SIZE; 4000 tnode_t *tn = build_integer_constant(SIZEOF_TSPEC, offset_in_bytes); 4001 tn->tn_system_dependent = true; 4002 return tn; 4003 } 4004 4005 unsigned int 4006 type_size_in_bits(const type_t *tp) 4007 { 4008 4009 unsigned int elem = 1; 4010 bool flex = false; 4011 lint_assert(tp != NULL); 4012 while (tp->t_tspec == ARRAY) { 4013 flex = true; /* allow c99 flex arrays [] [0] */ 4014 elem *= tp->t_dim; 4015 tp = tp->t_subt; 4016 } 4017 if (elem == 0 && !flex) { 4018 /* cannot take size/alignment of incomplete type */ 4019 error(143); 4020 elem = 1; 4021 } 4022 4023 unsigned int elsz; 4024 switch (tp->t_tspec) { 4025 case VOID: 4026 /* cannot take size/alignment of void */ 4027 error(146); 4028 elsz = 1; 4029 break; 4030 case FUNC: 4031 /* cannot take size/alignment of function type '%s' */ 4032 error(144, type_name(tp)); 4033 elsz = 1; 4034 break; 4035 case STRUCT: 4036 case UNION: 4037 if (is_incomplete(tp)) { 4038 /* cannot take size/alignment of incomplete type */ 4039 error(143); 4040 elsz = 1; 4041 } else { 4042 elsz = tp->t_sou->sou_size_in_bits; 4043 } 4044 break; 4045 case ENUM: 4046 if (is_incomplete(tp)) { 4047 /* cannot take size/alignment of incomplete type */ 4048 warning(143); 4049 } 4050 /* FALLTHROUGH */ 4051 default: 4052 if (tp->t_bitfield) { 4053 /* cannot take size/alignment of bit-field */ 4054 error(145); 4055 } 4056 elsz = size_in_bits(tp->t_tspec); 4057 lint_assert(elsz > 0); 4058 break; 4059 } 4060 4061 return elem * elsz; 4062 } 4063 4064 /* C11 6.5.3.4, GCC */ 4065 tnode_t * 4066 build_alignof(const type_t *tp) 4067 { 4068 if (tp->t_tspec == FUNC) { 4069 /* cannot take size/alignment of function type '%s' */ 4070 error(144, type_name(tp)); 4071 return NULL; 4072 } 4073 if (tp->t_tspec == VOID) { 4074 /* cannot take size/alignment of void */ 4075 error(146); 4076 return NULL; 4077 } 4078 if (is_incomplete(tp)) { 4079 /* cannot take size/alignment of incomplete type */ 4080 error(143); 4081 return NULL; 4082 } 4083 if (tp->t_bitfield) { 4084 /* cannot take size/alignment of bit-field */ 4085 error(145); 4086 return NULL; 4087 } 4088 return build_integer_constant(SIZEOF_TSPEC, 4089 (int64_t)alignment_in_bits(tp) / CHAR_SIZE); 4090 } 4091 4092 static tnode_t * 4093 cast_to_union(tnode_t *otn, type_t *ntp) 4094 { 4095 4096 if (!allow_gcc) { 4097 /* union cast is a GCC extension */ 4098 error(328); 4099 return NULL; 4100 } 4101 4102 for (const sym_t *m = ntp->t_sou->sou_first_member; 4103 m != NULL; m = m->s_next) { 4104 if (types_compatible(m->s_type, otn->tn_type, 4105 false, false, NULL)) { 4106 tnode_t *ntn = expr_alloc_tnode(); 4107 ntn->tn_op = CVT; 4108 ntn->tn_type = ntp; 4109 ntn->tn_cast = true; 4110 ntn->tn_left = otn; 4111 ntn->tn_right = NULL; 4112 return ntn; 4113 } 4114 } 4115 4116 /* type '%s' is not a member of '%s' */ 4117 error(329, type_name(otn->tn_type), type_name(ntp)); 4118 return NULL; 4119 } 4120 4121 /* 4122 * Type casts. 4123 */ 4124 tnode_t * 4125 cast(tnode_t *tn, type_t *tp) 4126 { 4127 4128 if (tn == NULL) 4129 return NULL; 4130 4131 tn = cconv(tn); 4132 4133 lint_assert(tp != NULL); 4134 tspec_t nt = tp->t_tspec; 4135 tspec_t ot = tn->tn_type->t_tspec; 4136 4137 if (nt == VOID) { 4138 /* 4139 * C90 6.3.4, C99 6.5.4p2 and C11 6.5.4p2 allow any type to 4140 * be cast to void. The only other allowed casts are from a 4141 * scalar type to a scalar type. 4142 */ 4143 } else if (nt == UNION) 4144 return cast_to_union(tn, tp); 4145 else if (nt == STRUCT || nt == ARRAY || nt == FUNC) { 4146 /* Casting to a struct is an undocumented GCC extension. */ 4147 if (!(allow_gcc && nt == STRUCT)) 4148 goto invalid_cast; 4149 } else if (is_struct_or_union(ot)) 4150 goto invalid_cast; 4151 else if (ot == VOID) { 4152 /* improper cast of void expression */ 4153 error(148); 4154 return NULL; 4155 } else if (is_integer(nt) && is_scalar(ot)) { 4156 /* ok */ 4157 } else if (is_floating(nt) && is_arithmetic(ot)) { 4158 /* ok */ 4159 } else if (nt == PTR && is_integer(ot)) { 4160 /* ok */ 4161 } else if (nt == PTR && ot == PTR) { 4162 if (!tp->t_subt->t_const && tn->tn_type->t_subt->t_const) { 4163 if (hflag) 4164 /* cast discards 'const' from type '%s' */ 4165 warning(275, type_name(tn->tn_type)); 4166 } 4167 } else 4168 goto invalid_cast; 4169 4170 if (any_query_enabled && types_compatible(tp, tn->tn_type, 4171 false, false, NULL)) { 4172 /* no-op cast from '%s' to '%s' */ 4173 query_message(6, type_name(tn->tn_type), type_name(tp)); 4174 } 4175 4176 tn = convert(CVT, 0, tp, tn); 4177 tn->tn_cast = true; 4178 4179 return tn; 4180 4181 invalid_cast: 4182 /* invalid cast from '%s' to '%s' */ 4183 error(147, type_name(tn->tn_type), type_name(tp)); 4184 return NULL; 4185 } 4186 4187 /* 4188 * Create the node for a function argument. 4189 * All necessary conversions and type checks are done in 4190 * build_function_call because build_function_argument has no 4191 * information about expected argument types. 4192 */ 4193 tnode_t * 4194 build_function_argument(tnode_t *args, tnode_t *arg) 4195 { 4196 /* 4197 * If there was a serious error in the expression for the argument, 4198 * create a dummy argument so the positions of the remaining arguments 4199 * will not change. 4200 */ 4201 if (arg == NULL) 4202 arg = build_integer_constant(INT, 0); 4203 4204 return new_tnode(PUSH, arg->tn_sys, arg->tn_type, arg, args); 4205 } 4206 4207 /* 4208 * Compare the type of an argument with the corresponding type of a 4209 * prototype parameter. If it is a valid combination, but both types 4210 * are not the same, insert a conversion to convert the argument into 4211 * the type of the parameter. 4212 */ 4213 static tnode_t * 4214 check_prototype_argument( 4215 int n, /* pos of arg */ 4216 type_t *tp, /* expected type (from prototype) */ 4217 tnode_t *tn) /* argument */ 4218 { 4219 tnode_t *ln = xcalloc(1, sizeof(*ln)); 4220 ln->tn_type = expr_unqualified_type(tp); 4221 ln->tn_lvalue = true; 4222 if (typeok(FARG, n, ln, tn)) { 4223 bool dowarn; 4224 if (!types_compatible(tp, tn->tn_type, 4225 true, false, (dowarn = false, &dowarn)) || dowarn) 4226 tn = convert(FARG, n, tp, tn); 4227 } 4228 free(ln); 4229 return tn; 4230 } 4231 4232 /* 4233 * Check types of all function arguments and insert conversions, 4234 * if necessary. 4235 */ 4236 static tnode_t * 4237 check_function_arguments(type_t *ftp, tnode_t *args) 4238 { 4239 /* get # of parameters in the prototype */ 4240 int npar = 0; 4241 for (sym_t *asym = ftp->t_args; asym != NULL; asym = asym->s_next) 4242 npar++; 4243 4244 /* get # of arguments in the function call */ 4245 int narg = 0; 4246 for (tnode_t *arg = args; arg != NULL; arg = arg->tn_right) 4247 narg++; 4248 4249 sym_t *asym = ftp->t_args; 4250 if (ftp->t_proto && npar != narg && !(ftp->t_vararg && npar < narg)) { 4251 /* argument mismatch: %d %s passed, %d expected */ 4252 error(150, narg, narg > 1 ? "arguments" : "argument", npar); 4253 asym = NULL; 4254 } 4255 4256 for (int n = 1; n <= narg; n++) { 4257 4258 /* 4259 * The rightmost argument is at the top of the argument 4260 * subtree. 4261 */ 4262 tnode_t *arg = args; 4263 for (int i = narg; i > n; i--, arg = arg->tn_right) 4264 continue; 4265 4266 /* some things which are always not allowed */ 4267 tspec_t at = arg->tn_left->tn_type->t_tspec; 4268 if (at == VOID) { 4269 /* void expressions may not be arguments, arg #%d */ 4270 error(151, n); 4271 return NULL; 4272 } else if (is_struct_or_union(at) && 4273 is_incomplete(arg->tn_left->tn_type)) { 4274 /* argument cannot have unknown size, arg #%d */ 4275 error(152, n); 4276 return NULL; 4277 } else if (is_integer(at) && 4278 arg->tn_left->tn_type->t_is_enum && 4279 is_incomplete(arg->tn_left->tn_type)) { 4280 /* argument cannot have unknown size, arg #%d */ 4281 warning(152, n); 4282 } 4283 4284 /* class conversions (arg in value context) */ 4285 arg->tn_left = cconv(arg->tn_left); 4286 4287 if (asym != NULL) { 4288 arg->tn_left = check_prototype_argument( 4289 n, asym->s_type, arg->tn_left); 4290 } else 4291 arg->tn_left = promote(NOOP, true, arg->tn_left); 4292 arg->tn_type = arg->tn_left->tn_type; 4293 4294 if (asym != NULL) 4295 asym = asym->s_next; 4296 } 4297 4298 return args; 4299 } 4300 4301 /* 4302 * Create the node for a function call. Also check types of 4303 * function arguments and insert conversions, if necessary. 4304 */ 4305 tnode_t * 4306 build_function_call(tnode_t *func, bool sys, tnode_t *args) 4307 { 4308 4309 if (func == NULL) 4310 return NULL; 4311 4312 op_t fcop = func->tn_op == NAME && func->tn_type->t_tspec == FUNC 4313 ? CALL : ICALL; 4314 4315 check_ctype_function_call(func, args); 4316 4317 /* Turn the function name into a pointer to the function. */ 4318 func = cconv(func); 4319 4320 if (func->tn_type->t_tspec != PTR || 4321 func->tn_type->t_subt->t_tspec != FUNC) { 4322 /* cannot call '%s', must be a function */ 4323 error(149, type_name(func->tn_type)); 4324 return NULL; 4325 } 4326 4327 args = check_function_arguments(func->tn_type->t_subt, args); 4328 4329 return new_tnode(fcop, sys, func->tn_type->t_subt->t_subt, func, args); 4330 } 4331 4332 /* 4333 * Return the value of an integral constant expression. 4334 * If the expression is not constant or its type is not an integer 4335 * type, an error message is printed. 4336 */ 4337 val_t * 4338 integer_constant(tnode_t *tn, bool required) 4339 { 4340 4341 if (tn != NULL) 4342 tn = cconv(tn); 4343 if (tn != NULL) 4344 tn = promote(NOOP, false, tn); 4345 4346 val_t *v = xcalloc(1, sizeof(*v)); 4347 4348 if (tn == NULL) { 4349 lint_assert(seen_error); 4350 debug_step("constant node is null; returning 1 instead"); 4351 v->v_tspec = INT; 4352 v->u.integer = 1; 4353 return v; 4354 } 4355 4356 v->v_tspec = tn->tn_type->t_tspec; 4357 4358 if (tn->tn_op == CON) { 4359 lint_assert(tn->tn_type->t_tspec == tn->tn_val.v_tspec); 4360 if (is_integer(tn->tn_val.v_tspec)) { 4361 v->v_unsigned_since_c90 = 4362 tn->tn_val.v_unsigned_since_c90; 4363 v->u.integer = tn->tn_val.u.integer; 4364 return v; 4365 } 4366 v->u.integer = (int64_t)tn->tn_val.u.floating; 4367 } else { 4368 v->u.integer = 1; 4369 } 4370 4371 if (required) 4372 /* integral constant expression expected */ 4373 error(55); 4374 else 4375 /* variable array dimension is a C99/GCC extension */ 4376 c99ism(318); 4377 4378 if (!is_integer(v->v_tspec)) 4379 v->v_tspec = INT; 4380 4381 return v; 4382 } 4383 4384 static bool 4385 is_constcond_false(const tnode_t *tn, tspec_t t) 4386 { 4387 return (t == BOOL || t == INT) && 4388 tn->tn_op == CON && tn->tn_val.u.integer == 0; 4389 } 4390 4391 /* 4392 * Perform some tests on expressions which can't be done in build_binary() 4393 * and functions called by build_binary(). These tests must be done here 4394 * because we need some information about the context in which the operations 4395 * are performed. 4396 * After all tests are performed and dofreeblk is true, expr() frees the 4397 * memory which is used for the expression. 4398 */ 4399 void 4400 expr(tnode_t *tn, bool vctx, bool cond, bool dofreeblk, bool is_do_while) 4401 { 4402 4403 if (tn == NULL) { /* in case of errors */ 4404 expr_free_all(); 4405 return; 4406 } 4407 4408 /* expr() is also called in global initializations */ 4409 if (dcs->d_kind != DLK_EXTERN && !is_do_while) 4410 check_statement_reachable(); 4411 4412 check_expr_misc(tn, vctx, cond, !cond, false, false, false); 4413 if (tn->tn_op == ASSIGN && !tn->tn_parenthesized) { 4414 if (hflag && cond) 4415 /* assignment in conditional context */ 4416 warning(159); 4417 } else if (tn->tn_op == CON) { 4418 if (hflag && cond && !constcond_flag && 4419 !tn->tn_system_dependent && 4420 !(is_do_while && 4421 is_constcond_false(tn, tn->tn_type->t_tspec))) 4422 /* constant in conditional context */ 4423 warning(161); 4424 } 4425 if (!modtab[tn->tn_op].m_has_side_effect) { 4426 /* 4427 * for left operands of COMMA this warning is already 4428 * printed 4429 */ 4430 if (tn->tn_op != COMMA && !vctx && !cond) 4431 check_null_effect(tn); 4432 } 4433 debug_node(tn); 4434 4435 /* free the tree memory */ 4436 if (dofreeblk) 4437 expr_free_all(); 4438 } 4439 4440 /* 4441 * Checks the range of array indices, if possible. 4442 * amper is set if only the address of the element is used. This 4443 * means that the index is allowed to refer to the first element 4444 * after the array. 4445 */ 4446 static void 4447 check_array_index(tnode_t *tn, bool amper) 4448 { 4449 const tnode_t *ln = tn->tn_left; 4450 const tnode_t *rn = tn->tn_right; 4451 4452 /* We can only check constant indices. */ 4453 if (rn->tn_op != CON) 4454 return; 4455 4456 /* Return if the left node does not stem from an array. */ 4457 if (ln->tn_op != ADDR) 4458 return; 4459 if (ln->tn_left->tn_op != STRING && ln->tn_left->tn_op != NAME) 4460 return; 4461 if (ln->tn_left->tn_type->t_tspec != ARRAY) 4462 return; 4463 4464 /* 4465 * For incomplete array types, we can print a warning only if 4466 * the index is negative. 4467 */ 4468 if (is_incomplete(ln->tn_left->tn_type) && rn->tn_val.u.integer >= 0) 4469 return; 4470 4471 /* Get the size of one array element */ 4472 int elsz = length_in_bits(ln->tn_type->t_subt, NULL); 4473 if (elsz == 0) 4474 return; 4475 elsz /= CHAR_SIZE; 4476 4477 /* Change the unit of the index from bytes to element size. */ 4478 int64_t con = is_uinteger(rn->tn_type->t_tspec) 4479 ? (int64_t)((uint64_t)rn->tn_val.u.integer / elsz) 4480 : rn->tn_val.u.integer / elsz; 4481 4482 int dim = ln->tn_left->tn_type->t_dim + (amper ? 1 : 0); 4483 4484 if (!is_uinteger(rn->tn_type->t_tspec) && con < 0) { 4485 /* array subscript cannot be negative: %ld */ 4486 warning(167, (long)con); 4487 } else if (dim > 0 && (uint64_t)con >= (uint64_t)dim) { 4488 /* array subscript cannot be > %d: %ld */ 4489 warning(168, dim - 1, (long)con); 4490 } 4491 } 4492 4493 static void 4494 check_expr_addr(const tnode_t *ln, bool szof, bool fcall) 4495 { 4496 /* XXX: Taking warn_about_unreachable into account here feels wrong. */ 4497 if (ln->tn_op == NAME && (reached || !warn_about_unreachable)) { 4498 if (!szof) 4499 mark_as_set(ln->tn_sym); 4500 mark_as_used(ln->tn_sym, fcall, szof); 4501 } 4502 if (ln->tn_op == INDIR && ln->tn_left->tn_op == PLUS) 4503 /* check the range of array indices */ 4504 check_array_index(ln->tn_left, true); 4505 } 4506 4507 static void 4508 check_expr_load(const tnode_t *ln) 4509 { 4510 if (ln->tn_op == INDIR && ln->tn_left->tn_op == PLUS) 4511 /* check the range of array indices */ 4512 check_array_index(ln->tn_left, false); 4513 } 4514 4515 /* 4516 * If there is an asm statement in one of the compound statements around, 4517 * there may be other side effects, so don't warn. 4518 */ 4519 static bool 4520 is_asm_around(void) 4521 { 4522 for (decl_level *dl = dcs; dl != NULL; dl = dl->d_enclosing) 4523 if (dl->d_asm) 4524 return true; 4525 return false; 4526 } 4527 4528 static void 4529 check_expr_side_effect(const tnode_t *ln, bool szof) 4530 { 4531 4532 /* XXX: Taking warn_about_unreachable into account here feels wrong. */ 4533 if (ln->tn_op == NAME && (reached || !warn_about_unreachable)) { 4534 scl_t sc = ln->tn_sym->s_scl; 4535 if (sc != EXTERN && sc != STATIC && 4536 !ln->tn_sym->s_set && !szof && !is_asm_around()) { 4537 /* '%s' may be used before set */ 4538 warning(158, ln->tn_sym->s_name); 4539 mark_as_set(ln->tn_sym); 4540 } 4541 mark_as_used(ln->tn_sym, false, false); 4542 } 4543 } 4544 4545 static void 4546 check_expr_assign(const tnode_t *ln, bool szof) 4547 { 4548 /* XXX: Taking warn_about_unreachable into account here feels wrong. */ 4549 if (ln->tn_op == NAME && !szof && (reached || !warn_about_unreachable)) { 4550 mark_as_set(ln->tn_sym); 4551 if (ln->tn_sym->s_scl == EXTERN) 4552 outusg(ln->tn_sym); 4553 } 4554 if (ln->tn_op == INDIR && ln->tn_left->tn_op == PLUS) 4555 /* check the range of array indices */ 4556 check_array_index(ln->tn_left, false); 4557 } 4558 4559 static void 4560 check_expr_call(const tnode_t *tn, const tnode_t *ln, 4561 bool szof, bool vctx, bool cond, bool retval_discarded) 4562 { 4563 lint_assert(ln->tn_op == ADDR); 4564 lint_assert(ln->tn_left->tn_op == NAME); 4565 if (!szof && !is_compiler_builtin(ln->tn_left->tn_sym->s_name)) 4566 outcall(tn, vctx || cond, retval_discarded); 4567 } 4568 4569 static bool 4570 check_expr_op(const tnode_t *tn, op_t op, const tnode_t *ln, 4571 bool szof, bool fcall, bool vctx, bool cond, 4572 bool retval_discarded, bool eqwarn) 4573 { 4574 switch (op) { 4575 case ADDR: 4576 check_expr_addr(ln, szof, fcall); 4577 break; 4578 case LOAD: 4579 check_expr_load(ln); 4580 /* FALLTHROUGH */ 4581 case PUSH: 4582 case INCBEF: 4583 case DECBEF: 4584 case INCAFT: 4585 case DECAFT: 4586 case ADDASS: 4587 case SUBASS: 4588 case MULASS: 4589 case DIVASS: 4590 case MODASS: 4591 case ANDASS: 4592 case ORASS: 4593 case XORASS: 4594 case SHLASS: 4595 case SHRASS: 4596 case REAL: 4597 case IMAG: 4598 check_expr_side_effect(ln, szof); 4599 break; 4600 case ASSIGN: 4601 check_expr_assign(ln, szof); 4602 break; 4603 case CALL: 4604 check_expr_call(tn, ln, szof, vctx, cond, retval_discarded); 4605 break; 4606 case EQ: 4607 if (hflag && eqwarn) 4608 /* operator '==' found where '=' was expected */ 4609 warning(160); 4610 break; 4611 case CON: 4612 case NAME: 4613 case STRING: 4614 return false; 4615 default: 4616 break; 4617 } 4618 return true; 4619 } 4620 4621 /* 4622 * vctx ??? 4623 * cond whether the expression is a condition that 4624 * will be compared with 0 4625 * eqwarn whether the operator '==' might be a 4626 * misspelled '=' 4627 * fcall whether the expression is a function call 4628 * retval_discarded whether the return value of a function call 4629 * is discarded; such calls will be analyzed by 4630 * lint2 in messages 4, 8 and 9 4631 * szof whether the expression is part of a sizeof 4632 * expression, which means that its value is 4633 * discarded since only the type is relevant 4634 */ 4635 void 4636 check_expr_misc(const tnode_t *tn, bool vctx, bool cond, 4637 bool eqwarn, bool fcall, bool retval_discarded, bool szof) 4638 { 4639 4640 if (tn == NULL) 4641 return; 4642 4643 tnode_t *ln = tn->tn_left; 4644 tnode_t *rn = tn->tn_right; 4645 op_t op = tn->tn_op; 4646 const mod_t *mp = &modtab[op]; 4647 4648 if (!check_expr_op(tn, op, ln, 4649 szof, fcall, vctx, cond, retval_discarded, eqwarn)) 4650 return; 4651 4652 bool cvctx = mp->m_value_context; 4653 bool ccond = mp->m_compares_with_zero; 4654 bool eq = mp->m_warn_if_operand_eq && 4655 !ln->tn_parenthesized && 4656 rn != NULL && !rn->tn_parenthesized; 4657 4658 /* 4659 * values of operands of ':' are not used if the type of at least 4660 * one of the operands (for gcc compatibility) is void 4661 * XXX test/value context of QUEST should probably be used as 4662 * context for both operands of COLON 4663 */ 4664 if (op == COLON && tn->tn_type->t_tspec == VOID) 4665 cvctx = ccond = false; 4666 bool discard = op == CVT && tn->tn_type->t_tspec == VOID; 4667 check_expr_misc(ln, cvctx, ccond, eq, op == CALL, discard, szof); 4668 4669 switch (op) { 4670 case PUSH: 4671 if (rn != NULL) 4672 check_expr_misc(rn, false, false, eq, false, false, 4673 szof); 4674 break; 4675 case LOGAND: 4676 case LOGOR: 4677 check_expr_misc(rn, false, true, eq, false, false, szof); 4678 break; 4679 case COLON: 4680 check_expr_misc(rn, cvctx, ccond, eq, false, false, szof); 4681 break; 4682 case COMMA: 4683 check_expr_misc(rn, vctx, cond, false, false, false, szof); 4684 break; 4685 default: 4686 if (mp->m_binary) 4687 check_expr_misc(rn, true, false, eq, false, false, 4688 szof); 4689 break; 4690 } 4691 } 4692 4693 /* 4694 * Return whether the expression can be used for static initialization. 4695 * 4696 * Constant initialization expressions must be constant or an address 4697 * of a static object with an optional offset. In the first case, 4698 * the result is returned in *offsp. In the second case, the static 4699 * object is returned in *symp and the offset in *offsp. 4700 * 4701 * The expression can consist of PLUS, MINUS, ADDR, NAME, STRING and 4702 * CON. Type conversions are allowed if they do not change binary 4703 * representation (including width). 4704 * 4705 * C99 6.6 "Constant expressions" 4706 * C99 6.7.8p4 restricts initializers for static storage duration 4707 */ 4708 bool 4709 constant_addr(const tnode_t *tn, const sym_t **symp, ptrdiff_t *offsp) 4710 { 4711 const sym_t *sym; 4712 ptrdiff_t offs1, offs2; 4713 tspec_t t, ot; 4714 4715 switch (tn->tn_op) { 4716 case MINUS: 4717 if (tn->tn_right->tn_op == CVT) 4718 return constant_addr(tn->tn_right, symp, offsp); 4719 else if (tn->tn_right->tn_op != CON) 4720 return false; 4721 /* FALLTHROUGH */ 4722 case PLUS: 4723 offs1 = offs2 = 0; 4724 if (tn->tn_left->tn_op == CON) { 4725 offs1 = (ptrdiff_t)tn->tn_left->tn_val.u.integer; 4726 if (!constant_addr(tn->tn_right, &sym, &offs2)) 4727 return false; 4728 } else if (tn->tn_right->tn_op == CON) { 4729 offs2 = (ptrdiff_t)tn->tn_right->tn_val.u.integer; 4730 if (tn->tn_op == MINUS) 4731 offs2 = -offs2; 4732 if (!constant_addr(tn->tn_left, &sym, &offs1)) 4733 return false; 4734 } else { 4735 return false; 4736 } 4737 *symp = sym; 4738 *offsp = offs1 + offs2; 4739 return true; 4740 case ADDR: 4741 if (tn->tn_left->tn_op == NAME) { 4742 *symp = tn->tn_left->tn_sym; 4743 *offsp = 0; 4744 return true; 4745 } else { 4746 /* 4747 * If this were the front end of a compiler, we 4748 * would return a label instead of 0, at least if 4749 * 'tn->tn_left->tn_op == STRING'. 4750 */ 4751 *symp = NULL; 4752 *offsp = 0; 4753 return true; 4754 } 4755 case CVT: 4756 t = tn->tn_type->t_tspec; 4757 ot = tn->tn_left->tn_type->t_tspec; 4758 if ((!is_integer(t) && t != PTR) || 4759 (!is_integer(ot) && ot != PTR)) { 4760 return false; 4761 } 4762 #if 0 4763 /* 4764 * consider: 4765 * struct foo { 4766 * unsigned char a; 4767 * } f = { 4768 * (unsigned char)(unsigned long) 4769 * (&(((struct foo *)0)->a)) 4770 * }; 4771 * since psize(unsigned long) != psize(unsigned char), 4772 * this fails. 4773 */ 4774 else if (psize(t) != psize(ot)) 4775 return -1; 4776 #endif 4777 return constant_addr(tn->tn_left, symp, offsp); 4778 default: 4779 return false; 4780 } 4781 } 4782 4783 /* Append s2 to s1, then free s2. */ 4784 strg_t * 4785 cat_strings(strg_t *s1, strg_t *s2) 4786 { 4787 4788 if (s1->st_char != s2->st_char) { 4789 /* cannot concatenate wide and regular string literals */ 4790 error(292); 4791 return s1; 4792 } 4793 4794 size_t len1 = s1->st_len; 4795 size_t len2 = s2->st_len; 4796 size_t chsize = s1->st_char ? sizeof(char) : sizeof(wchar_t); 4797 size_t size1 = len1 * chsize; 4798 size_t size2 = (len2 + 1) * chsize; 4799 s1->st_mem = xrealloc(s1->st_mem, size1 + size2); 4800 memcpy((char *)s1->st_mem + size1, s2->st_mem, size2); 4801 free(s2->st_mem); 4802 4803 s1->st_len = len1 + len2; 4804 free(s2); 4805 4806 return s1; 4807 } 4808 4809 4810 typedef struct stmt_expr { 4811 memory_pool se_mem; 4812 sym_t *se_sym; 4813 struct stmt_expr *se_enclosing; 4814 } stmt_expr; 4815 4816 static stmt_expr *stmt_exprs; 4817 4818 void 4819 begin_statement_expr(void) 4820 { 4821 stmt_expr *se = xmalloc(sizeof(*se)); 4822 se->se_mem = expr_save_memory(); 4823 se->se_sym = NULL; 4824 se->se_enclosing = stmt_exprs; 4825 stmt_exprs = se; 4826 } 4827 4828 void 4829 do_statement_expr(tnode_t *tn) 4830 { 4831 block_level--; 4832 mem_block_level--; 4833 stmt_exprs->se_sym = tn != NULL 4834 ? mktempsym(block_dup_type(tn->tn_type)) 4835 : NULL; /* after a syntax error */ 4836 mem_block_level++; 4837 block_level++; 4838 /* '({ ... })' is a GCC extension */ 4839 gnuism(320); 4840 } 4841 4842 tnode_t * 4843 end_statement_expr(void) 4844 { 4845 stmt_expr *se = stmt_exprs; 4846 if (se->se_sym == NULL) 4847 return NULL; /* after a syntax error */ 4848 tnode_t *tn = build_name(se->se_sym, false); 4849 (void)expr_save_memory(); /* leak */ 4850 expr_restore_memory(se->se_mem); 4851 stmt_exprs = se->se_enclosing; 4852 free(se); 4853 return tn; 4854 } 4855
Indexes created Mon Sep 22 13:09:51 GMT 2025