tree.c revision 1.583
1 /* $NetBSD: tree.c,v 1.583 2023/12/02 21:53:15 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 1.583 2023/12/02 21:53:15 rillig Exp $"); 41 #endif 42 43 #include <float.h> 44 #include <limits.h> 45 #include <math.h> 46 #include <signal.h> 47 #include <stdlib.h> 48 #include <string.h> 49 50 #include "lint1.h" 51 52 53 typedef struct integer_constraints { 54 int64_t smin; /* signed minimum */ 55 int64_t smax; /* signed maximum */ 56 uint64_t umin; /* unsigned minimum */ 57 uint64_t umax; /* unsigned maximum */ 58 uint64_t bset; /* bits that are definitely set */ 59 uint64_t bclr; /* bits that are definitely clear */ 60 } integer_constraints; 61 62 63 static uint64_t 64 u64_fill_right(uint64_t x) 65 { 66 x |= x >> 1; 67 x |= x >> 2; 68 x |= x >> 4; 69 x |= x >> 8; 70 x |= x >> 16; 71 x |= x >> 32; 72 return x; 73 } 74 75 static bool 76 str_ends_with(const char *haystack, const char *needle) 77 { 78 size_t hlen = strlen(haystack); 79 size_t nlen = strlen(needle); 80 81 return nlen <= hlen && 82 memcmp(haystack + hlen - nlen, needle, nlen) == 0; 83 } 84 85 static unsigned 86 width_in_bits(const type_t *tp) 87 { 88 89 lint_assert(is_integer(tp->t_tspec)); 90 return tp->t_bitfield 91 ? tp->t_bit_field_width 92 : size_in_bits(tp->t_tspec); 93 } 94 95 static int 96 portable_rank_cmp(tspec_t t1, tspec_t t2) { 97 const ttab_t *p1 = type_properties(t1), *p2 = type_properties(t2); 98 lint_assert(p1->tt_rank_kind == p2->tt_rank_kind); 99 lint_assert(p1->tt_rank_value > 0); 100 lint_assert(p2->tt_rank_value > 0); 101 return (int)p1->tt_rank_value - (int)p2->tt_rank_value; 102 } 103 104 static bool 105 ic_maybe_signed(const type_t *tp, const integer_constraints *ic) 106 { 107 return !is_uinteger(tp->t_tspec) && ic->bclr >> 63 == 0; 108 } 109 110 static integer_constraints 111 ic_any(const type_t *tp) 112 { 113 integer_constraints c; 114 115 uint64_t vbits = value_bits(width_in_bits(tp)); 116 if (is_uinteger(tp->t_tspec)) { 117 c.smin = INT64_MIN; 118 c.smax = INT64_MAX; 119 c.umin = 0; 120 c.umax = vbits; 121 c.bset = 0; 122 c.bclr = ~c.umax; 123 } else { 124 c.smin = (int64_t)-1 - (int64_t)(vbits >> 1); 125 c.smax = (int64_t)(vbits >> 1); 126 c.umin = 0; 127 c.umax = UINT64_MAX; 128 c.bset = 0; 129 c.bclr = 0; 130 } 131 return c; 132 } 133 134 static integer_constraints 135 ic_con(const type_t *tp, const val_t *v) 136 { 137 integer_constraints c; 138 139 lint_assert(is_integer(tp->t_tspec)); 140 int64_t si = v->u.integer; 141 uint64_t ui = (uint64_t)si; 142 c.smin = si; 143 c.smax = si; 144 c.umin = ui; 145 c.umax = ui; 146 c.bset = ui; 147 c.bclr = ~ui; 148 return c; 149 } 150 151 static integer_constraints 152 ic_cvt(const type_t *ntp, const type_t *otp, integer_constraints a) 153 { 154 unsigned nw = width_in_bits(ntp); 155 unsigned ow = width_in_bits(otp); 156 bool nu = is_uinteger(ntp->t_tspec); 157 bool ou = is_uinteger(otp->t_tspec); 158 159 if (nw >= ow && nu == ou) 160 return a; 161 if (nw > ow && ou) 162 return a; 163 return ic_any(ntp); 164 } 165 166 static integer_constraints 167 ic_bitand(integer_constraints a, integer_constraints b) 168 { 169 integer_constraints c; 170 171 c.smin = INT64_MIN; 172 c.smax = INT64_MAX; 173 c.umin = 0; 174 c.umax = UINT64_MAX; 175 c.bset = a.bset & b.bset; 176 c.bclr = a.bclr | b.bclr; 177 return c; 178 } 179 180 static integer_constraints 181 ic_bitor(integer_constraints a, integer_constraints b) 182 { 183 integer_constraints c; 184 185 c.smin = INT64_MIN; 186 c.smax = INT64_MAX; 187 c.umin = 0; 188 c.umax = UINT64_MAX; 189 c.bset = a.bset | b.bset; 190 c.bclr = a.bclr & b.bclr; 191 return c; 192 } 193 194 static integer_constraints 195 ic_mod(const type_t *tp, integer_constraints a, integer_constraints b) 196 { 197 integer_constraints c; 198 199 if (ic_maybe_signed(tp, &a) || ic_maybe_signed(tp, &b)) 200 return ic_any(tp); 201 202 c.smin = INT64_MIN; 203 c.smax = INT64_MAX; 204 c.umin = 0; 205 c.umax = b.umax - 1; 206 c.bset = 0; 207 c.bclr = ~u64_fill_right(c.umax); 208 return c; 209 } 210 211 static integer_constraints 212 ic_shl(const type_t *tp, integer_constraints a, integer_constraints b) 213 { 214 integer_constraints c; 215 unsigned int amount; 216 217 if (ic_maybe_signed(tp, &a)) 218 return ic_any(tp); 219 220 if (b.smin == b.smax && b.smin >= 0 && b.smin < 64) 221 amount = (unsigned int)b.smin; 222 else if (b.umin == b.umax && b.umin < 64) 223 amount = (unsigned int)b.umin; 224 else 225 return ic_any(tp); 226 227 c.smin = INT64_MIN; 228 c.smax = INT64_MAX; 229 c.umin = 0; 230 c.umax = UINT64_MAX; 231 c.bset = a.bset << amount; 232 c.bclr = a.bclr << amount | (((uint64_t)1 << amount) - 1); 233 return c; 234 } 235 236 static integer_constraints 237 ic_shr(const type_t *tp, integer_constraints a, integer_constraints b) 238 { 239 integer_constraints c; 240 unsigned int amount; 241 242 if (ic_maybe_signed(tp, &a)) 243 return ic_any(tp); 244 245 if (b.smin == b.smax && b.smin >= 0 && b.smin < 64) 246 amount = (unsigned int)b.smin; 247 else if (b.umin == b.umax && b.umin < 64) 248 amount = (unsigned int)b.umin; 249 else 250 return ic_any(tp); 251 252 c.smin = INT64_MIN; 253 c.smax = INT64_MAX; 254 c.umin = 0; 255 c.umax = UINT64_MAX; 256 c.bset = a.bset >> amount; 257 c.bclr = a.bclr >> amount | ~(~(uint64_t)0 >> amount); 258 return c; 259 } 260 261 static integer_constraints 262 ic_cond(integer_constraints a, integer_constraints b) 263 { 264 integer_constraints c; 265 266 c.smin = a.smin < b.smin ? a.smin : b.smin; 267 c.smax = a.smax > b.smax ? a.smax : b.smax; 268 c.umin = a.umin < b.umin ? a.umin : b.umin; 269 c.umax = a.umax > b.umax ? a.umax : b.umax; 270 c.bset = a.bset | b.bset; 271 c.bclr = a.bclr & b.bclr; 272 return c; 273 } 274 275 static integer_constraints 276 ic_expr(const tnode_t *tn) 277 { 278 integer_constraints lc, rc; 279 280 lint_assert(is_integer(tn->tn_type->t_tspec)); 281 282 switch (tn->tn_op) { 283 case CON: 284 return ic_con(tn->tn_type, &tn->tn_val); 285 case CVT: 286 if (!is_integer(tn->tn_left->tn_type->t_tspec)) 287 return ic_any(tn->tn_type); 288 lc = ic_expr(tn->tn_left); 289 return ic_cvt(tn->tn_type, tn->tn_left->tn_type, lc); 290 case MOD: 291 lc = ic_expr(before_conversion(tn->tn_left)); 292 rc = ic_expr(before_conversion(tn->tn_right)); 293 return ic_mod(tn->tn_type, lc, rc); 294 case SHL: 295 lc = ic_expr(tn->tn_left); 296 rc = ic_expr(tn->tn_right); 297 return ic_shl(tn->tn_type, lc, rc); 298 case SHR: 299 lc = ic_expr(tn->tn_left); 300 rc = ic_expr(tn->tn_right); 301 return ic_shr(tn->tn_type, lc, rc); 302 case BITAND: 303 lc = ic_expr(tn->tn_left); 304 rc = ic_expr(tn->tn_right); 305 return ic_bitand(lc, rc); 306 case BITOR: 307 lc = ic_expr(tn->tn_left); 308 rc = ic_expr(tn->tn_right); 309 return ic_bitor(lc, rc); 310 case QUEST: 311 lc = ic_expr(tn->tn_right->tn_left); 312 rc = ic_expr(tn->tn_right->tn_right); 313 return ic_cond(lc, rc); 314 default: 315 return ic_any(tn->tn_type); 316 } 317 } 318 319 /* Build 'pointer to tp', 'array of tp' or 'function returning tp'. */ 320 type_t * 321 block_derive_type(type_t *tp, tspec_t t) 322 { 323 type_t *tp2; 324 325 tp2 = block_zero_alloc(sizeof(*tp2), "type"); 326 tp2->t_tspec = t; 327 tp2->t_subt = tp; 328 return tp2; 329 } 330 331 /* 332 * Derive 'pointer to tp' or 'function returning tp'. 333 * The memory is freed at the end of the current expression. 334 */ 335 type_t * 336 expr_derive_type(type_t *tp, tspec_t t) 337 { 338 type_t *tp2; 339 340 tp2 = expr_zero_alloc(sizeof(*tp2), "type"); 341 tp2->t_tspec = t; 342 tp2->t_subt = tp; 343 return tp2; 344 } 345 346 /* Create an expression from a unary or binary operator and its operands. */ 347 static tnode_t * 348 build_op(op_t op, bool sys, type_t *type, tnode_t *ln, tnode_t *rn) 349 { 350 351 tnode_t *ntn = expr_alloc_tnode(); 352 ntn->tn_op = op; 353 ntn->tn_type = type; 354 ntn->tn_sys = sys; 355 ntn->tn_left = ln; 356 ntn->tn_right = rn; 357 358 if (op == INDIR || op == FSEL) { 359 lint_assert(ln->tn_type->t_tspec == PTR); 360 tspec_t t = ln->tn_type->t_subt->t_tspec; 361 ntn->tn_lvalue = t != FUNC && t != VOID; 362 } 363 364 return ntn; 365 } 366 367 tnode_t * 368 build_constant(type_t *tp, val_t *v) 369 { 370 371 tnode_t *n = expr_alloc_tnode(); 372 n->tn_op = CON; 373 n->tn_type = tp; 374 n->tn_val = *v; 375 n->tn_val.v_tspec = tp->t_tspec; 376 free(v); 377 return n; 378 } 379 380 static tnode_t * 381 build_integer_constant(tspec_t t, int64_t si) 382 { 383 384 tnode_t *n = expr_alloc_tnode(); 385 n->tn_op = CON; 386 n->tn_type = gettyp(t); 387 n->tn_val.v_tspec = t; 388 n->tn_val.v_unsigned_since_c90 = false; 389 n->tn_val.v_char_constant = false; 390 n->tn_val.u.integer = si; 391 return n; 392 } 393 394 static void 395 fallback_symbol(sym_t *sym) 396 { 397 398 if (Tflag && fallback_symbol_strict_bool(sym)) 399 return; 400 401 if (block_level > 0 && (strcmp(sym->s_name, "__FUNCTION__") == 0 || 402 strcmp(sym->s_name, "__PRETTY_FUNCTION__") == 0)) { 403 /* __FUNCTION__/__PRETTY_FUNCTION__ is a GCC extension */ 404 gnuism(316); 405 // XXX: Should probably be ARRAY instead of PTR. 406 sym->s_type = block_derive_type(gettyp(CHAR), PTR); 407 sym->s_type->t_const = true; 408 return; 409 } 410 411 if (block_level > 0 && strcmp(sym->s_name, "__func__") == 0) { 412 if (!allow_c99) 413 /* __func__ is a C99 feature */ 414 warning(317); 415 /* C11 6.4.2.2 */ 416 sym->s_type = block_derive_type(gettyp(CHAR), ARRAY); 417 sym->s_type->t_const = true; 418 sym->s_type->t_dim = (int)strlen(funcsym->s_name) + 1; 419 return; 420 } 421 422 /* '%s' undefined */ 423 error(99, sym->s_name); 424 } 425 426 /* 427 * Functions that are predeclared by GCC or other compilers can be called 428 * with arbitrary arguments. Since lint usually runs after a successful 429 * compilation, it's the compiler's job to catch any errors. 430 */ 431 bool 432 is_compiler_builtin(const char *name) 433 { 434 /* https://gcc.gnu.org/onlinedocs/gcc/C-Extensions.html */ 435 if (allow_gcc) { 436 if (strncmp(name, "__atomic_", 9) == 0 || 437 strncmp(name, "__builtin_", 10) == 0 || 438 strcmp(name, "alloca") == 0 || 439 /* obsolete but still in use, as of 2021 */ 440 strncmp(name, "__sync_", 7) == 0) 441 return true; 442 } 443 444 /* https://software.intel.com/sites/landingpage/IntrinsicsGuide/ */ 445 if (strncmp(name, "_mm_", 4) == 0) 446 return true; 447 448 return false; 449 } 450 451 /* https://gcc.gnu.org/onlinedocs/gcc/Integer-Overflow-Builtins.html */ 452 static bool 453 is_gcc_bool_builtin(const char *name) 454 { 455 return strncmp(name, "__builtin_", 10) == 0 && 456 (str_ends_with(name, "_overflow") || 457 str_ends_with(name, "_overflow_p")); 458 } 459 460 static void 461 build_name_call(sym_t *sym) 462 { 463 464 if (is_compiler_builtin(sym->s_name)) { 465 /* 466 * Do not warn about these, just assume that 467 * they are regular functions compatible with 468 * non-prototype calling conventions. 469 */ 470 if (allow_gcc && is_gcc_bool_builtin(sym->s_name)) 471 sym->s_type = gettyp(BOOL); 472 } else if (allow_c99) { 473 /* function '%s' implicitly declared to return int */ 474 error(215, sym->s_name); 475 } else if (!allow_trad) { 476 /* function '%s' implicitly declared to return int */ 477 warning(215, sym->s_name); 478 } 479 480 /* XXX if !allow_c90, the symbol should be exported to level 0 */ 481 sym->s_type = block_derive_type(sym->s_type, FUNC); 482 } 483 484 /* Create a node for a name (symbol table entry). */ 485 tnode_t * 486 build_name(sym_t *sym, bool is_funcname) 487 { 488 489 if (sym->s_scl == NO_SCL && !in_gcc_attribute) { 490 sym->s_scl = EXTERN; 491 sym->s_def = DECL; 492 if (is_funcname) 493 build_name_call(sym); 494 else 495 fallback_symbol(sym); 496 } 497 498 lint_assert(sym->s_kind == FVFT || sym->s_kind == FMEMBER); 499 500 tnode_t *n = expr_alloc_tnode(); 501 n->tn_type = sym->s_type; 502 if (sym->s_scl == BOOL_CONST) { 503 n->tn_op = CON; 504 n->tn_val.v_tspec = BOOL; 505 n->tn_val.v_unsigned_since_c90 = false; 506 n->tn_val.v_char_constant = false; 507 n->tn_val.u.integer = sym->u.s_bool_constant ? 1 : 0; 508 } else if (sym->s_scl == ENUM_CONST) { 509 n->tn_op = CON; 510 n->tn_val.v_tspec = INT; /* ENUM is in n->tn_type */ 511 n->tn_val.v_unsigned_since_c90 = false; 512 n->tn_val.v_char_constant = false; 513 n->tn_val.u.integer = sym->u.s_enum_constant; 514 } else { 515 n->tn_op = NAME; 516 n->tn_sym = sym; 517 if (sym->s_kind == FVFT && sym->s_type->t_tspec != FUNC) 518 n->tn_lvalue = true; 519 } 520 521 return n; 522 } 523 524 tnode_t * 525 build_string(strg_t *strg) 526 { 527 size_t len = strg->st_len; 528 529 type_t *tp = expr_zero_alloc(sizeof(*tp), "type"); 530 tp->t_tspec = ARRAY; 531 tp->t_subt = gettyp(strg->st_char ? CHAR : WCHAR_TSPEC); 532 tp->t_dim = (int)(len + 1); 533 534 tnode_t *n = expr_alloc_tnode(); 535 n->tn_op = STRING; 536 n->tn_type = tp; 537 n->tn_lvalue = true; 538 539 n->tn_string = expr_zero_alloc(sizeof(*n->tn_string), "type.string"); 540 n->tn_string->st_char = strg->st_char; 541 n->tn_string->st_len = len; 542 543 size_t chsize = strg->st_char ? sizeof(char) : sizeof(wchar_t); 544 size_t size = (len + 1) * chsize; 545 n->tn_string->st_mem = expr_zero_alloc(size, "type.string.data"); 546 (void)memcpy(n->tn_string->st_mem, strg->st_mem, size); 547 free(strg->st_mem); 548 free(strg); 549 550 return n; 551 } 552 553 tnode_t * 554 build_generic_selection(const tnode_t *expr, 555 struct generic_association *sel) 556 { 557 tnode_t *default_result = NULL; 558 559 for (; sel != NULL; sel = sel->ga_prev) { 560 if (expr != NULL && 561 types_compatible(sel->ga_arg, expr->tn_type, 562 false, false, NULL)) 563 return sel->ga_result; 564 else if (sel->ga_arg == NULL) 565 default_result = sel->ga_result; 566 } 567 return default_result; 568 } 569 570 static bool 571 is_out_of_char_range(const tnode_t *tn) 572 { 573 return tn->tn_op == CON && 574 !tn->tn_val.v_char_constant && 575 !(0 <= tn->tn_val.u.integer && 576 tn->tn_val.u.integer < 1 << (CHAR_SIZE - 1)); 577 } 578 579 static bool 580 check_nonportable_char_comparison(op_t op, 581 const tnode_t *ln, tspec_t lt, 582 const tnode_t *rn, tspec_t rt) 583 { 584 if (!(hflag || pflag)) 585 return true; 586 587 if (lt == CHAR && is_out_of_char_range(rn)) { 588 char buf[128]; 589 (void)snprintf(buf, sizeof(buf), "%s %d", 590 op_name(op), (int)rn->tn_val.u.integer); 591 /* nonportable character comparison '%s' */ 592 warning(230, buf); 593 return false; 594 } 595 if (rt == CHAR && is_out_of_char_range(ln)) { 596 char buf[128]; 597 (void)snprintf(buf, sizeof(buf), "%d %s ?", 598 (int)ln->tn_val.u.integer, op_name(op)); 599 /* nonportable character comparison '%s' */ 600 warning(230, buf); 601 return false; 602 } 603 return true; 604 } 605 606 static void 607 check_integer_comparison(op_t op, tnode_t *ln, tnode_t *rn) 608 { 609 610 tspec_t lt = ln->tn_type->t_tspec; 611 tspec_t rt = rn->tn_type->t_tspec; 612 613 if (ln->tn_op != CON && rn->tn_op != CON) 614 return; 615 616 if (!is_integer(lt) || !is_integer(rt)) 617 return; 618 619 if (any_query_enabled && !in_system_header) { 620 if (lt == CHAR && rn->tn_op == CON && 621 !rn->tn_val.v_char_constant) { 622 /* comparison '%s' of 'char' with plain integer %d */ 623 query_message(14, 624 op_name(op), (int)rn->tn_val.u.integer); 625 } 626 if (rt == CHAR && ln->tn_op == CON && 627 !ln->tn_val.v_char_constant) { 628 /* comparison '%s' of 'char' with plain integer %d */ 629 query_message(14, 630 op_name(op), (int)ln->tn_val.u.integer); 631 } 632 } 633 634 if (!check_nonportable_char_comparison(op, ln, lt, rn, rt)) 635 return; 636 637 if (is_uinteger(lt) && !is_uinteger(rt) && 638 rn->tn_op == CON && rn->tn_val.u.integer <= 0) { 639 if (rn->tn_val.u.integer < 0) { 640 /* operator '%s' compares '%s' with '%s' */ 641 warning(162, op_name(op), 642 type_name(ln->tn_type), "negative constant"); 643 } else if (op == LT || op == GE) { 644 /* operator '%s' compares '%s' with '%s' */ 645 warning(162, op_name(op), type_name(ln->tn_type), "0"); 646 } 647 return; 648 } 649 if (is_uinteger(rt) && !is_uinteger(lt) && 650 ln->tn_op == CON && ln->tn_val.u.integer <= 0) { 651 if (ln->tn_val.u.integer < 0) { 652 /* operator '%s' compares '%s' with '%s' */ 653 warning(162, op_name(op), 654 "negative constant", type_name(rn->tn_type)); 655 } else if (op == GT || op == LE) { 656 /* operator '%s' compares '%s' with '%s' */ 657 warning(162, op_name(op), "0", type_name(rn->tn_type)); 658 } 659 return; 660 } 661 } 662 663 static const tspec_t arith_rank[] = { 664 LDOUBLE, DOUBLE, FLOAT, 665 #ifdef INT128_SIZE 666 UINT128, INT128, 667 #endif 668 ULLONG, LLONG, 669 ULONG, LONG, 670 UINT, INT, 671 }; 672 673 /* Keep unsigned in traditional C */ 674 static tspec_t 675 usual_arithmetic_conversion_trad(tspec_t lt, tspec_t rt) 676 { 677 678 size_t i; 679 for (i = 0; arith_rank[i] != INT; i++) 680 if (lt == arith_rank[i] || rt == arith_rank[i]) 681 break; 682 683 tspec_t t = arith_rank[i]; 684 if (is_uinteger(lt) || is_uinteger(rt)) 685 if (is_integer(t) && !is_uinteger(t)) 686 return unsigned_type(t); 687 return t; 688 } 689 690 static tspec_t 691 usual_arithmetic_conversion_c90(tspec_t lt, tspec_t rt) 692 { 693 694 if (lt == rt) 695 return lt; 696 697 if (lt == LCOMPLEX || rt == LCOMPLEX) 698 return LCOMPLEX; 699 if (lt == DCOMPLEX || rt == DCOMPLEX) 700 return DCOMPLEX; 701 if (lt == FCOMPLEX || rt == FCOMPLEX) 702 return FCOMPLEX; 703 if (lt == LDOUBLE || rt == LDOUBLE) 704 return LDOUBLE; 705 if (lt == DOUBLE || rt == DOUBLE) 706 return DOUBLE; 707 if (lt == FLOAT || rt == FLOAT) 708 return FLOAT; 709 710 /* 711 * If type A has more bits than type B, it should be able to hold all 712 * possible values of type B. 713 */ 714 if (size_in_bits(lt) > size_in_bits(rt)) 715 return lt; 716 if (size_in_bits(lt) < size_in_bits(rt)) 717 return rt; 718 719 size_t i; 720 for (i = 3; arith_rank[i] != INT; i++) 721 if (arith_rank[i] == lt || arith_rank[i] == rt) 722 break; 723 if ((is_uinteger(lt) || is_uinteger(rt)) && 724 !is_uinteger(arith_rank[i])) 725 i--; 726 return arith_rank[i]; 727 } 728 729 static tnode_t * 730 apply_usual_arithmetic_conversions(op_t op, tnode_t *tn, tspec_t t) 731 { 732 type_t *ntp = expr_dup_type(tn->tn_type); 733 ntp->t_tspec = t; 734 if (tn->tn_op != CON) { 735 /* usual arithmetic conversion for '%s' from '%s' to '%s' */ 736 query_message(4, op_name(op), 737 type_name(tn->tn_type), type_name(ntp)); 738 } 739 return convert(op, 0, ntp, tn); 740 } 741 742 /* 743 * Apply the "usual arithmetic conversions" (C99 6.3.1.8), which gives both 744 * operands the same type. 745 */ 746 static void 747 balance(op_t op, tnode_t **lnp, tnode_t **rnp) 748 { 749 750 tspec_t lt = (*lnp)->tn_type->t_tspec; 751 tspec_t rt = (*rnp)->tn_type->t_tspec; 752 if (!is_arithmetic(lt) || !is_arithmetic(rt)) 753 return; 754 755 tspec_t t = allow_c90 756 ? usual_arithmetic_conversion_c90(lt, rt) 757 : usual_arithmetic_conversion_trad(lt, rt); 758 759 if (t != lt) 760 *lnp = apply_usual_arithmetic_conversions(op, *lnp, t); 761 if (t != rt) 762 *rnp = apply_usual_arithmetic_conversions(op, *rnp, t); 763 } 764 765 /* 766 * Create a tree node for the unary & operator 767 */ 768 static tnode_t * 769 build_address(bool sys, tnode_t *tn, bool noign) 770 { 771 tspec_t t; 772 773 if (!noign && ((t = tn->tn_type->t_tspec) == ARRAY || t == FUNC)) { 774 if (!allow_c90) 775 /* '&' before array or function: ignored */ 776 warning(127); 777 return tn; 778 } 779 780 /* eliminate &* */ 781 if (tn->tn_op == INDIR && 782 tn->tn_left->tn_type->t_tspec == PTR && 783 tn->tn_left->tn_type->t_subt == tn->tn_type) { 784 return tn->tn_left; 785 } 786 787 return build_op(ADDR, sys, expr_derive_type(tn->tn_type, PTR), 788 tn, NULL); 789 } 790 791 /* 792 * XXX 793 * Note: There appear to be a number of bugs in detecting overflow in 794 * this function. An audit and a set of proper regression tests are needed. 795 * --Perry Metzger, Nov. 16, 2001 796 */ 797 /* 798 * Do only as much as necessary to compute constant expressions. 799 * Called only if the operator allows folding and all operands are constants. 800 */ 801 static tnode_t * 802 fold(tnode_t *tn) 803 { 804 805 val_t *v = xcalloc(1, sizeof(*v)); 806 v->v_tspec = tn->tn_type->t_tspec; 807 808 lint_assert(has_operands(tn)); 809 tspec_t t = tn->tn_left->tn_type->t_tspec; 810 bool utyp = !is_integer(t) || is_uinteger(t); 811 int64_t sl = tn->tn_left->tn_val.u.integer, sr = 0; 812 uint64_t ul = sl, ur = 0; 813 if (is_binary(tn)) 814 ur = sr = tn->tn_right->tn_val.u.integer; 815 816 int64_t mask = (int64_t)value_bits(size_in_bits(t)); 817 bool ovfl = false; 818 819 int64_t si; 820 switch (tn->tn_op) { 821 case UPLUS: 822 si = sl; 823 break; 824 case UMINUS: 825 si = sl == INT64_MIN ? sl : -sl; 826 if (sl != 0 && msb(si, t) == msb(sl, t)) 827 ovfl = true; 828 break; 829 case COMPL: 830 si = ~sl; 831 break; 832 case MULT: 833 if (utyp) { 834 si = (int64_t)(ul * ur); 835 if (si != (si & mask)) 836 ovfl = true; 837 else if ((ul != 0) && ((si / ul) != ur)) 838 ovfl = true; 839 } else { 840 si = sl * sr; 841 if (msb(si, t) != (msb(sl, t) ^ msb(sr, t))) 842 ovfl = true; 843 } 844 break; 845 case DIV: 846 if (sr == 0) { 847 /* division by 0 */ 848 error(139); 849 si = utyp ? -1 : INT64_MAX; 850 } else { 851 si = utyp ? (int64_t)(ul / ur) : sl / sr; 852 } 853 break; 854 case MOD: 855 if (sr == 0) { 856 /* modulus by 0 */ 857 error(140); 858 si = 0; 859 } else { 860 si = utyp ? (int64_t)(ul % ur) : sl % sr; 861 } 862 break; 863 case PLUS: 864 si = utyp ? (int64_t)(ul + ur) : sl + sr; 865 if (msb(sl, t) && msb(sr, t) && !msb(si, t)) 866 ovfl = true; 867 if (!utyp && !msb(sl, t) && !msb(sr, t) && msb(si, t)) 868 ovfl = true; 869 break; 870 case MINUS: 871 si = utyp ? (int64_t)(ul - ur) : sl - sr; 872 if (!utyp && msb(sl, t) && !msb(sr, t) && !msb(si, t)) 873 ovfl = true; 874 if (!msb(sl, t) && msb(sr, t) && msb(si, t)) 875 ovfl = true; 876 break; 877 case SHL: 878 /* TODO: warn about out-of-bounds 'sr'. */ 879 /* TODO: warn about overflow in signed '<<'. */ 880 si = utyp ? (int64_t)(ul << (sr & 63)) : sl << (sr & 63); 881 break; 882 case SHR: 883 /* 884 * The sign must be explicitly extended because 885 * shifts of signed values are implementation dependent. 886 */ 887 /* TODO: warn about out-of-bounds 'sr'. */ 888 si = (int64_t)(ul >> (sr & 63)); 889 si = convert_integer(si, t, size_in_bits(t) - (int)sr); 890 break; 891 case LT: 892 si = (utyp ? ul < ur : sl < sr) ? 1 : 0; 893 break; 894 case LE: 895 si = (utyp ? ul <= ur : sl <= sr) ? 1 : 0; 896 break; 897 case GE: 898 si = (utyp ? ul >= ur : sl >= sr) ? 1 : 0; 899 break; 900 case GT: 901 si = (utyp ? ul > ur : sl > sr) ? 1 : 0; 902 break; 903 case EQ: 904 si = (utyp ? ul == ur : sl == sr) ? 1 : 0; 905 break; 906 case NE: 907 si = (utyp ? ul != ur : sl != sr) ? 1 : 0; 908 break; 909 case BITAND: 910 si = utyp ? (int64_t)(ul & ur) : sl & sr; 911 break; 912 case BITXOR: 913 si = utyp ? (int64_t)(ul ^ ur) : sl ^ sr; 914 break; 915 case BITOR: 916 si = utyp ? (int64_t)(ul | ur) : sl | sr; 917 break; 918 default: 919 lint_assert(/*CONSTCOND*/false); 920 } 921 922 /* XXX: The overflow check does not work for 64-bit integers. */ 923 if (ovfl || 924 ((uint64_t)(si | mask) != ~(uint64_t)0 && (si & ~mask) != 0)) { 925 if (hflag) 926 /* operator '%s' produces integer overflow */ 927 warning(141, op_name(tn->tn_op)); 928 } 929 930 v->u.integer = convert_integer(si, t, 0); 931 932 tnode_t *cn = build_constant(tn->tn_type, v); 933 if (tn->tn_left->tn_system_dependent) 934 cn->tn_system_dependent = true; 935 if (is_binary(tn) && tn->tn_right->tn_system_dependent) 936 cn->tn_system_dependent = true; 937 938 return cn; 939 } 940 941 /* 942 * Create a new node for one of the operators POINT and ARROW. 943 */ 944 static tnode_t * 945 build_struct_access(op_t op, bool sys, tnode_t *ln, tnode_t *rn) 946 { 947 948 lint_assert(rn->tn_op == NAME); 949 lint_assert(is_member(rn->tn_sym)); 950 951 bool lvalue = op == ARROW || ln->tn_lvalue; 952 953 if (op == POINT) { 954 ln = build_address(sys, ln, true); 955 } else if (ln->tn_type->t_tspec != PTR) { 956 lint_assert(!allow_c90); 957 lint_assert(is_integer(ln->tn_type->t_tspec)); 958 ln = convert(NOOP, 0, expr_derive_type(gettyp(VOID), PTR), ln); 959 } 960 961 tnode_t *ctn = build_integer_constant(PTRDIFF_TSPEC, 962 rn->tn_sym->u.s_member.sm_offset_in_bits / CHAR_SIZE); 963 964 type_t *ptr_tp = expr_derive_type(rn->tn_type, PTR); 965 tnode_t *ntn = build_op(PLUS, sys, ptr_tp, ln, ctn); 966 if (ln->tn_op == CON) 967 ntn = fold(ntn); 968 969 op_t nop = rn->tn_type->t_bitfield ? FSEL : INDIR; 970 ntn = build_op(nop, sys, ntn->tn_type->t_subt, ntn, NULL); 971 if (!lvalue) 972 ntn->tn_lvalue = false; 973 974 return ntn; 975 } 976 977 /* 978 * Get the size in bytes of type tp->t_subt, as a constant expression of type 979 * ptrdiff_t as seen from the target platform. 980 */ 981 static tnode_t * 982 subt_size_in_bytes(type_t *tp) 983 { 984 985 lint_assert(tp->t_tspec == PTR); 986 tp = tp->t_subt; 987 988 int elem = 1; 989 while (tp->t_tspec == ARRAY) { 990 elem *= tp->t_dim; 991 tp = tp->t_subt; 992 } 993 994 int elsz_in_bits = 0; 995 switch (tp->t_tspec) { 996 case FUNC: 997 /* pointer to function is not allowed here */ 998 error(110); 999 break; 1000 case VOID: 1001 /* cannot do pointer arithmetic on operand of unknown size */ 1002 gnuism(136); 1003 break; 1004 case STRUCT: 1005 case UNION: 1006 if ((elsz_in_bits = (int)tp->t_sou->sou_size_in_bits) == 0) 1007 /* cannot do pointer arithmetic on operand of ... */ 1008 error(136); 1009 break; 1010 case ENUM: 1011 if (is_incomplete(tp)) { 1012 /* cannot do pointer arithmetic on operand of ... */ 1013 warning(136); 1014 } 1015 /* FALLTHROUGH */ 1016 default: 1017 if ((elsz_in_bits = size_in_bits(tp->t_tspec)) == 0) { 1018 /* cannot do pointer arithmetic on operand of ... */ 1019 error(136); 1020 } else { 1021 lint_assert(elsz_in_bits != -1); 1022 } 1023 break; 1024 } 1025 1026 if (elem == 0 && elsz_in_bits != 0) { 1027 /* cannot do pointer arithmetic on operand of unknown size */ 1028 error(136); 1029 } 1030 1031 if (elsz_in_bits == 0) 1032 elsz_in_bits = CHAR_SIZE; 1033 1034 return build_integer_constant(PTRDIFF_TSPEC, 1035 (int64_t)(elem * elsz_in_bits / CHAR_SIZE)); 1036 } 1037 1038 /* 1039 * Create a node for INCAFT, INCBEF, DECAFT and DECBEF. 1040 */ 1041 static tnode_t * 1042 build_prepost_incdec(op_t op, bool sys, tnode_t *ln) 1043 { 1044 1045 lint_assert(ln != NULL); 1046 tnode_t *cn = ln->tn_type->t_tspec == PTR 1047 ? subt_size_in_bytes(ln->tn_type) 1048 : build_integer_constant(INT, 1); 1049 return build_op(op, sys, ln->tn_type, ln, cn); 1050 } 1051 1052 static void 1053 check_enum_array_index(const tnode_t *ln, const tnode_t *rn) 1054 { 1055 1056 if (ln->tn_op != ADDR || ln->tn_left->tn_op != NAME) 1057 return; 1058 1059 const type_t *ltp = ln->tn_left->tn_type; 1060 if (ltp->t_tspec != ARRAY || ltp->t_incomplete_array) 1061 return; 1062 1063 if (rn->tn_op != CVT || !rn->tn_type->t_is_enum) 1064 return; 1065 if (rn->tn_left->tn_op != LOAD) 1066 return; 1067 1068 const type_t *rtp = rn->tn_left->tn_type; 1069 const sym_t *ec = rtp->t_enum->en_first_enumerator; 1070 const sym_t *max_ec = ec; 1071 lint_assert(ec != NULL); 1072 for (ec = ec->s_next; ec != NULL; ec = ec->s_next) 1073 if (ec->u.s_enum_constant > max_ec->u.s_enum_constant) 1074 max_ec = ec; 1075 1076 int64_t max_enum_value = max_ec->u.s_enum_constant; 1077 lint_assert(INT_MIN <= max_enum_value && max_enum_value <= INT_MAX); 1078 1079 int max_array_index = ltp->t_dim - 1; 1080 if (max_enum_value == max_array_index) 1081 return; 1082 1083 /* 1084 * If the name of the largest enum constant contains 'MAX' or 'NUM', 1085 * that constant is typically not part of the allowed enum values but 1086 * a marker for the number of actual enum values. 1087 */ 1088 if (max_enum_value == max_array_index + 1 && 1089 (strstr(max_ec->s_name, "MAX") != NULL || 1090 strstr(max_ec->s_name, "max") != NULL || 1091 strstr(max_ec->s_name, "NUM") != NULL || 1092 strstr(max_ec->s_name, "num") != NULL)) 1093 return; 1094 1095 /* maximum value %d of '%s' does not match maximum array index %d */ 1096 warning(348, (int)max_enum_value, type_name(rtp), max_array_index); 1097 print_previous_declaration(max_ec); 1098 } 1099 1100 /* 1101 * Create a node for operators PLUS and MINUS. 1102 */ 1103 static tnode_t * 1104 build_plus_minus(op_t op, bool sys, tnode_t *ln, tnode_t *rn) 1105 { 1106 1107 /* If pointer and integer, move the pointer to the left. */ 1108 if (rn->tn_type->t_tspec == PTR && is_integer(ln->tn_type->t_tspec)) { 1109 tnode_t *tmp = ln; 1110 ln = rn; 1111 rn = tmp; 1112 /* pointer addition has integer on the left-hand side */ 1113 query_message(5); 1114 } 1115 1116 /* pointer +- integer */ 1117 if (ln->tn_type->t_tspec == PTR && rn->tn_type->t_tspec != PTR) { 1118 lint_assert(is_integer(rn->tn_type->t_tspec)); 1119 1120 check_ctype_macro_invocation(ln, rn); 1121 check_enum_array_index(ln, rn); 1122 1123 tnode_t *elsz = subt_size_in_bytes(ln->tn_type); 1124 if (rn->tn_type->t_tspec != elsz->tn_type->t_tspec) 1125 rn = convert(NOOP, 0, elsz->tn_type, rn); 1126 1127 tnode_t *prod = build_op(MULT, sys, rn->tn_type, rn, elsz); 1128 if (rn->tn_op == CON) 1129 prod = fold(prod); 1130 1131 return build_op(op, sys, ln->tn_type, ln, prod); 1132 } 1133 1134 /* pointer - pointer */ 1135 if (rn->tn_type->t_tspec == PTR) { 1136 lint_assert(ln->tn_type->t_tspec == PTR); 1137 lint_assert(op == MINUS); 1138 1139 type_t *ptrdiff = gettyp(PTRDIFF_TSPEC); 1140 tnode_t *raw_diff = build_op(op, sys, ptrdiff, ln, rn); 1141 if (ln->tn_op == CON && rn->tn_op == CON) 1142 raw_diff = fold(raw_diff); 1143 1144 tnode_t *elsz = subt_size_in_bytes(ln->tn_type); 1145 balance(NOOP, &raw_diff, &elsz); 1146 1147 return build_op(DIV, sys, ptrdiff, raw_diff, elsz); 1148 } 1149 1150 return build_op(op, sys, ln->tn_type, ln, rn); 1151 } 1152 1153 /* 1154 * Create a node for operators SHL and SHR. 1155 */ 1156 static tnode_t * 1157 build_bit_shift(op_t op, bool sys, tnode_t *ln, tnode_t *rn) 1158 { 1159 1160 if (!allow_c90 && rn->tn_type->t_tspec != INT) 1161 // XXX: C1978 7.5 says: "Both [operators] perform the usual 1162 // arithmetic conversions on their operands." 1163 // TODO: Add a test to exercise this part of the code. 1164 rn = convert(NOOP, 0, gettyp(INT), rn); 1165 return build_op(op, sys, ln->tn_type, ln, rn); 1166 } 1167 1168 static bool 1169 is_null_pointer(const tnode_t *tn) 1170 { 1171 tspec_t t = tn->tn_type->t_tspec; 1172 1173 // TODO: Investigate how other pointers are stored, in particular, 1174 // whether a pointer constant can have a non-zero value. 1175 // If not, simplify the code below. 1176 return ((t == PTR && tn->tn_type->t_subt->t_tspec == VOID) || 1177 is_integer(t)) 1178 && (tn->tn_op == CON && tn->tn_val.u.integer == 0); 1179 } 1180 1181 /* Return a type based on tp1, with added qualifiers from tp2. */ 1182 static type_t * 1183 merge_qualifiers(type_t *tp1, const type_t *tp2) 1184 { 1185 1186 lint_assert(tp1->t_tspec == PTR); 1187 lint_assert(tp2->t_tspec == PTR); 1188 1189 bool c1 = tp1->t_subt->t_const; 1190 bool c2 = tp2->t_subt->t_const; 1191 bool v1 = tp1->t_subt->t_volatile; 1192 bool v2 = tp2->t_subt->t_volatile; 1193 1194 if (c1 == (c1 | c2) && v1 == (v1 | v2)) 1195 return tp1; 1196 1197 type_t *nstp = expr_dup_type(tp1->t_subt); 1198 nstp->t_const |= c2; 1199 nstp->t_volatile |= v2; 1200 1201 type_t *ntp = expr_dup_type(tp1); 1202 ntp->t_subt = nstp; 1203 return ntp; 1204 } 1205 1206 /* See C99 6.5.15 "Conditional operator". */ 1207 static tnode_t * 1208 build_colon(bool sys, tnode_t *ln, tnode_t *rn) 1209 { 1210 1211 tspec_t lt = ln->tn_type->t_tspec; 1212 tspec_t rt = rn->tn_type->t_tspec; 1213 1214 type_t *tp; 1215 if (is_arithmetic(lt) && is_arithmetic(rt)) { 1216 /* The operands were already balanced in build_binary. */ 1217 tp = ln->tn_type; 1218 } else if (lt == BOOL && rt == BOOL) { 1219 tp = ln->tn_type; 1220 } else if (lt == VOID || rt == VOID) { 1221 tp = gettyp(VOID); 1222 } else if (is_struct_or_union(lt)) { 1223 /* Both types must be identical. */ 1224 lint_assert(is_struct_or_union(rt)); 1225 lint_assert(ln->tn_type->t_sou == rn->tn_type->t_sou); 1226 if (is_incomplete(ln->tn_type)) { 1227 /* unknown operand size, op '%s' */ 1228 error(138, op_name(COLON)); 1229 return NULL; 1230 } 1231 tp = ln->tn_type; 1232 } else if (lt == PTR && is_integer(rt)) { 1233 if (rt != PTRDIFF_TSPEC) 1234 rn = convert(NOOP, 0, gettyp(PTRDIFF_TSPEC), rn); 1235 tp = ln->tn_type; 1236 } else if (rt == PTR && is_integer(lt)) { 1237 if (lt != PTRDIFF_TSPEC) 1238 ln = convert(NOOP, 0, gettyp(PTRDIFF_TSPEC), ln); 1239 tp = rn->tn_type; 1240 } else if (lt == PTR && is_null_pointer(rn)) { 1241 tp = merge_qualifiers(ln->tn_type, rn->tn_type); 1242 } else if (rt == PTR && is_null_pointer(ln)) { 1243 tp = merge_qualifiers(rn->tn_type, ln->tn_type); 1244 } else if (lt == PTR && ln->tn_type->t_subt->t_tspec == VOID) { 1245 tp = merge_qualifiers(ln->tn_type, rn->tn_type); 1246 } else if (rt == PTR && rn->tn_type->t_subt->t_tspec == VOID) { 1247 tp = merge_qualifiers(rn->tn_type, ln->tn_type); 1248 } else { 1249 /* 1250 * XXX For now we simply take the left type. This is 1251 * probably wrong, if one type contains a function prototype 1252 * and the other one, at the same place, only an old-style 1253 * declaration. 1254 */ 1255 tp = merge_qualifiers(ln->tn_type, rn->tn_type); 1256 } 1257 1258 return build_op(COLON, sys, tp, ln, rn); 1259 } 1260 1261 /* TODO: check for varargs */ 1262 static bool 1263 is_cast_redundant(const tnode_t *tn) 1264 { 1265 const type_t *ntp = tn->tn_type, *otp = tn_ck_left(tn)->tn_type; 1266 tspec_t nt = ntp->t_tspec, ot = otp->t_tspec; 1267 1268 if (nt == BOOL || ot == BOOL) 1269 return nt == BOOL && ot == BOOL; 1270 1271 if (is_integer(nt) && is_integer(ot)) { 1272 unsigned int nw = width_in_bits(ntp), ow = width_in_bits(otp); 1273 if (is_uinteger(nt) == is_uinteger(ot)) 1274 return nw >= ow; 1275 return is_uinteger(ot) && nw > ow; 1276 } 1277 1278 if (is_complex(nt) || is_complex(ot)) 1279 return is_complex(nt) && is_complex(ot) && 1280 size_in_bits(nt) >= size_in_bits(ot); 1281 1282 if (is_floating(nt) && is_floating(ot)) 1283 return size_in_bits(nt) >= size_in_bits(ot); 1284 1285 if (nt == PTR && ot == PTR) { 1286 if (!ntp->t_subt->t_const && otp->t_subt->t_const) 1287 return false; 1288 if (!ntp->t_subt->t_volatile && otp->t_subt->t_volatile) 1289 return false; 1290 1291 if (ntp->t_subt->t_tspec == VOID || 1292 otp->t_subt->t_tspec == VOID || 1293 types_compatible(ntp->t_subt, otp->t_subt, 1294 false, false, NULL)) 1295 return true; 1296 } 1297 1298 return false; 1299 } 1300 1301 static bool 1302 is_assignment(op_t op) 1303 { 1304 1305 return op == ASSIGN || 1306 op == MULASS || 1307 op == DIVASS || 1308 op == MODASS || 1309 op == ADDASS || 1310 op == SUBASS || 1311 op == SHLASS || 1312 op == SHRASS || 1313 op == ANDASS || 1314 op == XORASS || 1315 op == ORASS || 1316 op == RETURN || 1317 op == INIT; 1318 } 1319 1320 /* Create a node for an assignment operator (both '=' and 'op='). */ 1321 static tnode_t * 1322 build_assignment(op_t op, bool sys, tnode_t *ln, tnode_t *rn) 1323 { 1324 1325 tspec_t lt = ln->tn_type->t_tspec; 1326 tspec_t rt = rn->tn_type->t_tspec; 1327 1328 if (any_query_enabled && is_assignment(rn->tn_op)) { 1329 /* chained assignment with '%s' and '%s' */ 1330 query_message(10, op_name(op), op_name(rn->tn_op)); 1331 } 1332 1333 if ((op == ADDASS || op == SUBASS) && lt == PTR) { 1334 lint_assert(is_integer(rt)); 1335 tnode_t *ctn = subt_size_in_bytes(ln->tn_type); 1336 if (rn->tn_type->t_tspec != ctn->tn_type->t_tspec) 1337 rn = convert(NOOP, 0, ctn->tn_type, rn); 1338 rn = build_op(MULT, sys, rn->tn_type, rn, ctn); 1339 if (rn->tn_left->tn_op == CON) 1340 rn = fold(rn); 1341 } 1342 1343 if ((op == ASSIGN || op == RETURN || op == INIT) && 1344 (lt == STRUCT || rt == STRUCT)) { 1345 lint_assert(lt == rt); 1346 lint_assert(ln->tn_type->t_sou == rn->tn_type->t_sou); 1347 if (is_incomplete(ln->tn_type)) { 1348 if (op == RETURN) { 1349 /* cannot return incomplete type */ 1350 error(212); 1351 } else { 1352 /* unknown operand size, op '%s' */ 1353 error(138, op_name(op)); 1354 } 1355 return NULL; 1356 } 1357 } 1358 1359 if (op == SHLASS && hflag && allow_trad && allow_c90 1360 && portable_rank_cmp(lt, rt) < 0) 1361 /* semantics of '%s' change in C90; ... */ 1362 warning(118, "<<="); 1363 1364 if (op != SHLASS && op != SHRASS 1365 && (op == ASSIGN || lt != PTR) 1366 && (lt != rt || (ln->tn_type->t_bitfield && rn->tn_op == CON))) { 1367 rn = convert(op, 0, ln->tn_type, rn); 1368 rt = lt; 1369 } 1370 1371 if (any_query_enabled && rn->tn_op == CVT && rn->tn_cast && 1372 types_compatible(ln->tn_type, rn->tn_type, false, false, NULL) && 1373 is_cast_redundant(rn)) { 1374 /* redundant cast from '%s' to '%s' before assignment */ 1375 query_message(7, 1376 type_name(rn->tn_left->tn_type), type_name(rn->tn_type)); 1377 } 1378 1379 return build_op(op, sys, ln->tn_type, ln, rn); 1380 } 1381 1382 /* 1383 * Create a node for REAL, IMAG 1384 */ 1385 static tnode_t * 1386 build_real_imag(op_t op, bool sys, tnode_t *ln) 1387 { 1388 1389 lint_assert(ln != NULL); 1390 if (ln->tn_op == NAME) { 1391 /* 1392 * This may be too much, but it avoids wrong warnings. 1393 * See d_c99_complex_split.c. 1394 */ 1395 mark_as_used(ln->tn_sym, false, false); 1396 mark_as_set(ln->tn_sym); 1397 } 1398 1399 tspec_t t; 1400 switch (ln->tn_type->t_tspec) { 1401 case LCOMPLEX: 1402 t = LDOUBLE; 1403 break; 1404 case DCOMPLEX: 1405 t = DOUBLE; 1406 break; 1407 case FCOMPLEX: 1408 t = FLOAT; 1409 break; 1410 default: 1411 /* '__%s__' is illegal for type '%s' */ 1412 error(276, op == REAL ? "real" : "imag", 1413 type_name(ln->tn_type)); 1414 return NULL; 1415 } 1416 1417 tnode_t *ntn = build_op(op, sys, gettyp(t), ln, NULL); 1418 ntn->tn_lvalue = true; 1419 return ntn; 1420 } 1421 1422 static bool 1423 is_confusing_precedence(op_t op, op_t lop, bool lparen, op_t rop, bool rparen) 1424 { 1425 1426 if (op == SHL || op == SHR) { 1427 if (!lparen && (lop == PLUS || lop == MINUS)) 1428 return true; 1429 if (!rparen && (rop == PLUS || rop == MINUS)) 1430 return true; 1431 return false; 1432 } 1433 1434 if (op == LOGOR) { 1435 if (!lparen && lop == LOGAND) 1436 return true; 1437 if (!rparen && rop == LOGAND) 1438 return true; 1439 return false; 1440 } 1441 1442 lint_assert(op == BITAND || op == BITXOR || op == BITOR); 1443 if (!lparen && lop != op) { 1444 if (lop == PLUS || lop == MINUS) 1445 return true; 1446 if (lop == BITAND || lop == BITXOR) 1447 return true; 1448 } 1449 if (!rparen && rop != op) { 1450 if (rop == PLUS || rop == MINUS) 1451 return true; 1452 if (rop == BITAND || rop == BITXOR) 1453 return true; 1454 } 1455 return false; 1456 } 1457 1458 /* 1459 * Print a warning if the given node has operands which should be 1460 * parenthesized. 1461 * 1462 * XXX Does not work if an operand is a constant expression. Constant 1463 * expressions are already folded. 1464 */ 1465 static void 1466 check_precedence_confusion(tnode_t *tn) 1467 { 1468 tnode_t *ln, *rn; 1469 1470 if (!hflag) 1471 return; 1472 1473 debug_node(tn); 1474 1475 lint_assert(is_binary(tn)); 1476 for (ln = tn->tn_left; ln->tn_op == CVT; ln = ln->tn_left) 1477 continue; 1478 for (rn = tn->tn_right; rn->tn_op == CVT; rn = rn->tn_left) 1479 continue; 1480 1481 if (is_confusing_precedence(tn->tn_op, 1482 ln->tn_op, ln->tn_parenthesized, 1483 rn->tn_op, rn->tn_parenthesized)) { 1484 /* precedence confusion possible: parenthesize! */ 1485 warning(169); 1486 } 1487 } 1488 1489 /* 1490 * Fold constant nodes, as much as is needed for comparing the value with 0. 1491 */ 1492 static tnode_t * 1493 fold_bool(tnode_t *tn) 1494 { 1495 1496 val_t *v = xcalloc(1, sizeof(*v)); 1497 v->v_tspec = tn->tn_type->t_tspec; 1498 lint_assert(v->v_tspec == INT || (Tflag && v->v_tspec == BOOL)); 1499 1500 lint_assert(has_operands(tn)); 1501 bool l = constant_is_nonzero(tn->tn_left); 1502 bool r = is_binary(tn) && constant_is_nonzero(tn->tn_right); 1503 1504 switch (tn->tn_op) { 1505 case NOT: 1506 if (hflag && !suppress_constcond) 1507 /* constant operand to '!' */ 1508 warning(239); 1509 v->u.integer = !l ? 1 : 0; 1510 break; 1511 case LOGAND: 1512 v->u.integer = l && r ? 1 : 0; 1513 break; 1514 case LOGOR: 1515 v->u.integer = l || r ? 1 : 0; 1516 break; 1517 default: 1518 lint_assert(/*CONSTCOND*/false); 1519 } 1520 1521 return build_constant(tn->tn_type, v); 1522 } 1523 1524 static long double 1525 floating_error_value(tspec_t t, long double lv) 1526 { 1527 if (t == FLOAT) 1528 return lv < 0 ? -FLT_MAX : FLT_MAX; 1529 if (t == DOUBLE) 1530 return lv < 0 ? -DBL_MAX : DBL_MAX; 1531 /* 1532 * When NetBSD is cross-built in MKLINT=yes mode on x86_64 for 1533 * sparc64, tools/lint checks this code while building usr.bin/xlint. 1534 * In that situation, lint uses the preprocessor for sparc64, in which 1535 * the type 'long double' is IEEE-754-binary128, affecting the macro 1536 * LDBL_MAX below. The type 'long double', as well as the strtold 1537 * implementation, comes from the host platform x86_64 though, where 1538 * 'long double' consumes 128 bits as well but only uses 80 of them. 1539 * The exponent range of the two 'long double' types is the same, but 1540 * the maximum finite value differs due to the extended precision on 1541 * sparc64. 1542 * 1543 * To properly handle the data types of the target platform, lint 1544 * would have to implement the floating-point types in a 1545 * platform-independent way, which is not worth the effort, given how 1546 * few programs practically use 'long double'. 1547 */ 1548 /* LINTED 248: floating-point constant out of range */ 1549 long double max = LDBL_MAX; 1550 return lv < 0 ? -max : max; 1551 } 1552 1553 static bool 1554 is_floating_overflow(tspec_t t, long double val) 1555 { 1556 if (fpe != 0 || isfinite(val) == 0) 1557 return true; 1558 if (t == FLOAT && (val > FLT_MAX || val < -FLT_MAX)) 1559 return true; 1560 if (t == DOUBLE && (val > DBL_MAX || val < -DBL_MAX)) 1561 return true; 1562 return false; 1563 } 1564 1565 /* 1566 * Fold constant nodes having operands with floating point type. 1567 */ 1568 static tnode_t * 1569 fold_float(tnode_t *tn) 1570 { 1571 1572 fpe = 0; 1573 1574 tspec_t t = tn->tn_type->t_tspec; 1575 1576 val_t *v = xcalloc(1, sizeof(*v)); 1577 v->v_tspec = t; 1578 1579 lint_assert(is_floating(t)); 1580 lint_assert(has_operands(tn)); 1581 lint_assert(t == tn->tn_left->tn_type->t_tspec); 1582 lint_assert(!is_binary(tn) || t == tn->tn_right->tn_type->t_tspec); 1583 1584 long double lv = tn->tn_left->tn_val.u.floating; 1585 long double rv = is_binary(tn) ? tn->tn_right->tn_val.u.floating : 0.0; 1586 1587 switch (tn->tn_op) { 1588 case UPLUS: 1589 v->u.floating = lv; 1590 break; 1591 case UMINUS: 1592 v->u.floating = -lv; 1593 break; 1594 case MULT: 1595 v->u.floating = lv * rv; 1596 break; 1597 case DIV: 1598 if (rv == 0.0) { 1599 /* division by 0 */ 1600 error(139); 1601 v->u.floating = floating_error_value(t, lv); 1602 } else { 1603 v->u.floating = lv / rv; 1604 } 1605 break; 1606 case PLUS: 1607 v->u.floating = lv + rv; 1608 break; 1609 case MINUS: 1610 v->u.floating = lv - rv; 1611 break; 1612 case LT: 1613 v->u.integer = lv < rv ? 1 : 0; 1614 break; 1615 case LE: 1616 v->u.integer = lv <= rv ? 1 : 0; 1617 break; 1618 case GE: 1619 v->u.integer = lv >= rv ? 1 : 0; 1620 break; 1621 case GT: 1622 v->u.integer = lv > rv ? 1 : 0; 1623 break; 1624 case EQ: 1625 v->u.integer = lv == rv ? 1 : 0; 1626 break; 1627 case NE: 1628 v->u.integer = lv != rv ? 1 : 0; 1629 break; 1630 default: 1631 lint_assert(/*CONSTCOND*/false); 1632 } 1633 1634 // XXX: Must not access u.floating after setting u.integer. 1635 lint_assert(fpe != 0 || isnan(v->u.floating) == 0); 1636 if (is_complex(v->v_tspec)) { 1637 /* 1638 * Don't warn, as lint doesn't model the imaginary part of 1639 * complex numbers. 1640 */ 1641 fpe = 0; 1642 } else if (is_floating_overflow(t, v->u.floating)) { 1643 /* operator '%s' produces floating point overflow */ 1644 warning(142, op_name(tn->tn_op)); 1645 v->u.floating = floating_error_value(t, v->u.floating); 1646 fpe = 0; 1647 } 1648 1649 return build_constant(tn->tn_type, v); 1650 } 1651 1652 static void 1653 use(const tnode_t *tn) 1654 { 1655 if (tn == NULL) 1656 return; 1657 switch (tn->tn_op) { 1658 case NAME: 1659 mark_as_used(tn->tn_sym, false /* XXX */, false /* XXX */); 1660 break; 1661 case CON: 1662 case STRING: 1663 break; 1664 default: 1665 lint_assert(has_operands(tn)); 1666 use(tn->tn_left); 1667 if (is_binary(tn) || tn->tn_op == PUSH) 1668 use(tn->tn_right); 1669 } 1670 } 1671 1672 /* 1673 * Create a tree node for a binary operator and its two operands. Also called 1674 * for unary operators; in that case rn is NULL. 1675 * 1676 * Function calls, sizeof and casts are handled elsewhere. 1677 */ 1678 tnode_t * 1679 build_binary(tnode_t *ln, op_t op, bool sys, tnode_t *rn) 1680 { 1681 const mod_t *mp = &modtab[op]; 1682 1683 /* If there was an error in one of the operands, return. */ 1684 if (ln == NULL || (mp->m_binary && rn == NULL)) 1685 return NULL; 1686 1687 /* 1688 * Apply class conversions to the left operand, but only if its 1689 * value is needed or compared with zero. 1690 */ 1691 if (mp->m_value_context || mp->m_compares_with_zero) 1692 ln = cconv(ln); 1693 /* 1694 * The right operand is almost always in a test or value context, 1695 * except if it is a struct or union member. 1696 */ 1697 if (mp->m_binary && op != ARROW && op != POINT) 1698 rn = cconv(rn); 1699 1700 /* 1701 * Print some warnings for comparisons of unsigned values with 1702 * constants lower than or equal to null. This must be done 1703 * before promote() because otherwise unsigned char and unsigned 1704 * short would be promoted to int. Types are also tested to be 1705 * CHAR, which would also become int. 1706 */ 1707 if (mp->m_comparison) 1708 check_integer_comparison(op, ln, rn); 1709 1710 if (mp->m_value_context || mp->m_compares_with_zero) 1711 ln = promote(op, false, ln); 1712 if (mp->m_binary && op != ARROW && op != POINT && 1713 op != ASSIGN && op != RETURN && op != INIT) { 1714 rn = promote(op, false, rn); 1715 } 1716 1717 /* 1718 * If the result of the operation is different for signed or 1719 * unsigned operands and one of the operands is signed only in 1720 * C90, print a warning. 1721 */ 1722 if (mp->m_warn_if_left_unsigned_in_c90 && 1723 ln->tn_op == CON && ln->tn_val.v_unsigned_since_c90) { 1724 /* C90 treats constant as unsigned, op '%s' */ 1725 warning(218, op_name(op)); 1726 ln->tn_val.v_unsigned_since_c90 = false; 1727 } 1728 if (mp->m_warn_if_right_unsigned_in_c90 && 1729 rn->tn_op == CON && rn->tn_val.v_unsigned_since_c90) { 1730 /* C90 treats constant as unsigned, op '%s' */ 1731 warning(218, op_name(op)); 1732 rn->tn_val.v_unsigned_since_c90 = false; 1733 } 1734 1735 /* Make sure both operands are of the same type */ 1736 if (mp->m_balance_operands || (!allow_c90 && (op == SHL || op == SHR))) 1737 balance(op, &ln, &rn); 1738 1739 /* 1740 * Check types for compatibility with the operation and mutual 1741 * compatibility. Return if there are serious problems. 1742 */ 1743 if (!typeok(op, 0, ln, rn)) 1744 return NULL; 1745 1746 /* And now create the node. */ 1747 tnode_t *ntn; 1748 switch (op) { 1749 case POINT: 1750 case ARROW: 1751 ntn = build_struct_access(op, sys, ln, rn); 1752 break; 1753 case INCAFT: 1754 case DECAFT: 1755 case INCBEF: 1756 case DECBEF: 1757 ntn = build_prepost_incdec(op, sys, ln); 1758 break; 1759 case ADDR: 1760 ntn = build_address(sys, ln, false); 1761 break; 1762 case INDIR: 1763 ntn = build_op(INDIR, sys, ln->tn_type->t_subt, ln, NULL); 1764 break; 1765 case PLUS: 1766 case MINUS: 1767 ntn = build_plus_minus(op, sys, ln, rn); 1768 break; 1769 case SHL: 1770 case SHR: 1771 ntn = build_bit_shift(op, sys, ln, rn); 1772 break; 1773 case COLON: 1774 ntn = build_colon(sys, ln, rn); 1775 break; 1776 case ASSIGN: 1777 case MULASS: 1778 case DIVASS: 1779 case MODASS: 1780 case ADDASS: 1781 case SUBASS: 1782 case SHLASS: 1783 case SHRASS: 1784 case ANDASS: 1785 case XORASS: 1786 case ORASS: 1787 case RETURN: 1788 case INIT: 1789 ntn = build_assignment(op, sys, ln, rn); 1790 break; 1791 case COMMA: 1792 if (any_query_enabled) { 1793 /* comma operator with types '%s' and '%s' */ 1794 query_message(12, 1795 type_name(ln->tn_type), type_name(rn->tn_type)); 1796 } 1797 /* FALLTHROUGH */ 1798 case QUEST: 1799 ntn = build_op(op, sys, rn->tn_type, ln, rn); 1800 break; 1801 case REAL: 1802 case IMAG: 1803 ntn = build_real_imag(op, sys, ln); 1804 break; 1805 default: 1806 lint_assert(mp->m_binary == (rn != NULL)); 1807 type_t *rettp = mp->m_returns_bool 1808 ? gettyp(Tflag ? BOOL : INT) : ln->tn_type; 1809 ntn = build_op(op, sys, rettp, ln, rn); 1810 break; 1811 } 1812 1813 /* Return if an error occurred. */ 1814 if (ntn == NULL) 1815 return NULL; 1816 1817 /* Print a warning if precedence confusion is possible */ 1818 if (mp->m_possible_precedence_confusion) 1819 check_precedence_confusion(ntn); 1820 1821 /* 1822 * Print a warning if one of the operands is in a context where 1823 * it is compared with zero and if this operand is a constant. 1824 */ 1825 if (hflag && !suppress_constcond && 1826 mp->m_compares_with_zero && 1827 (ln->tn_op == CON || 1828 ((mp->m_binary && op != QUEST) && rn->tn_op == CON)) && 1829 /* XXX: rn->tn_system_dependent should be checked as well */ 1830 !ln->tn_system_dependent) { 1831 /* constant in conditional context */ 1832 warning(161); 1833 } 1834 1835 /* Fold if the operator requires it */ 1836 if (mp->m_fold_constant_operands) { 1837 if (ln->tn_op == CON && (!mp->m_binary || rn->tn_op == CON)) { 1838 if (mp->m_compares_with_zero) { 1839 ntn = fold_bool(ntn); 1840 } else if (is_floating(ntn->tn_type->t_tspec)) { 1841 ntn = fold_float(ntn); 1842 } else { 1843 ntn = fold(ntn); 1844 } 1845 } else if (op == QUEST && ln->tn_op == CON) { 1846 lint_assert(has_operands(rn)); 1847 use(ln->tn_val.u.integer != 0 1848 ? rn->tn_right : rn->tn_left); 1849 ntn = ln->tn_val.u.integer != 0 1850 ? rn->tn_left : rn->tn_right; 1851 } 1852 } 1853 1854 return ntn; 1855 } 1856 1857 tnode_t * 1858 build_unary(op_t op, bool sys, tnode_t *tn) 1859 { 1860 return build_binary(tn, op, sys, NULL); 1861 } 1862 1863 static bool 1864 are_members_compatible(const sym_t *a, const sym_t *b) 1865 { 1866 if (a->u.s_member.sm_offset_in_bits != b->u.s_member.sm_offset_in_bits) 1867 return false; 1868 1869 const type_t *atp = a->s_type; 1870 const type_t *btp = b->s_type; 1871 bool w = false; 1872 if (!types_compatible(atp, btp, false, false, &w) && !w) 1873 return false; 1874 if (a->s_bitfield != b->s_bitfield) 1875 return false; 1876 if (a->s_bitfield) { 1877 if (atp->t_bit_field_width != btp->t_bit_field_width) 1878 return false; 1879 if (atp->t_bit_field_offset != btp->t_bit_field_offset) 1880 return false; 1881 } 1882 return true; 1883 } 1884 1885 /* 1886 * Return whether all struct/union members with the same name have the same 1887 * type and offset. 1888 */ 1889 static bool 1890 all_members_compatible(const sym_t *msym) 1891 { 1892 for (const sym_t *csym = msym; 1893 csym != NULL; csym = csym->s_symtab_next) { 1894 if (!is_member(csym)) 1895 continue; 1896 if (strcmp(msym->s_name, csym->s_name) != 0) 1897 continue; 1898 1899 for (const sym_t *sym = csym->s_symtab_next; 1900 sym != NULL; sym = sym->s_symtab_next) { 1901 if (is_member(sym) 1902 && strcmp(csym->s_name, sym->s_name) == 0 1903 && !are_members_compatible(csym, sym)) 1904 return false; 1905 } 1906 } 1907 return true; 1908 } 1909 1910 sym_t * 1911 find_member(const struct_or_union *sou, const char *name) 1912 { 1913 for (sym_t *mem = sou->sou_first_member; 1914 mem != NULL; mem = mem->s_next) { 1915 lint_assert(is_member(mem)); 1916 lint_assert(mem->u.s_member.sm_containing_type == sou); 1917 if (strcmp(mem->s_name, name) == 0) 1918 return mem; 1919 } 1920 1921 for (sym_t *mem = sou->sou_first_member; 1922 mem != NULL; mem = mem->s_next) { 1923 if (is_struct_or_union(mem->s_type->t_tspec) 1924 && mem->s_name == unnamed) { 1925 sym_t *nested_mem = 1926 find_member(mem->s_type->t_sou, name); 1927 if (nested_mem != NULL) 1928 return nested_mem; 1929 } 1930 } 1931 return NULL; 1932 } 1933 1934 /* 1935 * Remove the member if it was unknown until now, which means 1936 * that no defined struct or union has a member with the same name. 1937 */ 1938 static void 1939 remove_unknown_member(tnode_t *tn, sym_t *msym) 1940 { 1941 /* type '%s' does not have member '%s' */ 1942 error(101, type_name(tn->tn_type), msym->s_name); 1943 rmsym(msym); 1944 msym->s_kind = FMEMBER; 1945 msym->s_scl = STRUCT_MEMBER; 1946 1947 struct_or_union *sou = expr_zero_alloc(sizeof(*sou), 1948 "struct_or_union"); 1949 sou->sou_tag = expr_zero_alloc(sizeof(*sou->sou_tag), "sym"); 1950 sou->sou_tag->s_name = unnamed; 1951 1952 msym->u.s_member.sm_containing_type = sou; 1953 /* 1954 * The member sm_offset_in_bits is not needed here since this 1955 * symbol can only be used for error reporting. 1956 */ 1957 } 1958 1959 /* 1960 * Returns a symbol which has the same name as 'msym' and is a member of the 1961 * struct or union specified by 'tn'. 1962 */ 1963 static sym_t * 1964 struct_or_union_member(tnode_t *tn, op_t op, sym_t *msym) 1965 { 1966 1967 /* Determine the tag type of which msym is expected to be a member. */ 1968 const type_t *tp = NULL; 1969 if (op == POINT && is_struct_or_union(tn->tn_type->t_tspec)) 1970 tp = tn->tn_type; 1971 if (op == ARROW && tn->tn_type->t_tspec == PTR 1972 && is_struct_or_union(tn->tn_type->t_subt->t_tspec)) 1973 tp = tn->tn_type->t_subt; 1974 struct_or_union *sou = tp != NULL ? tp->t_sou : NULL; 1975 1976 if (sou != NULL) { 1977 sym_t *nested_mem = find_member(sou, msym->s_name); 1978 if (nested_mem != NULL) 1979 return nested_mem; 1980 } 1981 1982 if (msym->s_scl == NO_SCL) { 1983 remove_unknown_member(tn, msym); 1984 return msym; 1985 } 1986 1987 bool eq = all_members_compatible(msym); 1988 1989 /* 1990 * Now handle the case in which the left operand refers really 1991 * to a struct/union, but the right operand is not member of it. 1992 */ 1993 if (sou != NULL) { 1994 if (eq && !allow_c90) { 1995 /* illegal use of member '%s' */ 1996 warning(102, msym->s_name); 1997 } else { 1998 /* illegal use of member '%s' */ 1999 error(102, msym->s_name); 2000 } 2001 return msym; 2002 } 2003 2004 /* 2005 * Now the left operand of ARROW does not point to a struct/union 2006 * or the left operand of POINT is no struct/union. 2007 */ 2008 if (eq) { 2009 if (op == POINT) { 2010 if (!allow_c90) { 2011 /* left operand of '.' must be struct ... */ 2012 warning(103, type_name(tn->tn_type)); 2013 } else { 2014 /* left operand of '.' must be struct ... */ 2015 error(103, type_name(tn->tn_type)); 2016 } 2017 } else { 2018 if (!allow_c90 && tn->tn_type->t_tspec == PTR) { 2019 /* left operand of '->' must be pointer ... */ 2020 warning(104, type_name(tn->tn_type)); 2021 } else { 2022 /* left operand of '->' must be pointer ... */ 2023 error(104, type_name(tn->tn_type)); 2024 } 2025 } 2026 } else { 2027 if (!allow_c90) { 2028 /* non-unique member requires struct/union %s */ 2029 error(105, op == POINT ? "object" : "pointer"); 2030 } else { 2031 /* unacceptable operand of '%s' */ 2032 error(111, op_name(op)); 2033 } 2034 } 2035 2036 return msym; 2037 } 2038 2039 tnode_t * 2040 build_member_access(tnode_t *ln, op_t op, bool sys, sbuf_t *member) 2041 { 2042 sym_t *msym; 2043 2044 if (ln == NULL) 2045 return NULL; 2046 2047 if (op == ARROW) { 2048 /* must do this before struct_or_union_member is called */ 2049 ln = cconv(ln); 2050 } 2051 msym = struct_or_union_member(ln, op, getsym(member)); 2052 return build_binary(ln, op, sys, build_name(msym, false)); 2053 } 2054 2055 /* 2056 * Perform class conversions. 2057 * 2058 * Arrays of type T are converted into pointers to type T. 2059 * Functions are converted to pointers to functions. 2060 * Lvalues are converted to rvalues. 2061 * 2062 * C99 6.3 "Conversions" 2063 * C99 6.3.2 "Other operands" 2064 * C99 6.3.2.1 "Lvalues, arrays, and function designators" 2065 */ 2066 tnode_t * 2067 cconv(tnode_t *tn) 2068 { 2069 /* 2070 * Array-lvalue (array of type T) is converted into rvalue 2071 * (pointer to type T) 2072 */ 2073 if (tn->tn_type->t_tspec == ARRAY) { 2074 if (!tn->tn_lvalue) { 2075 /* XXX print correct operator */ 2076 /* %soperand of '%s' must be lvalue */ 2077 gnuism(114, "", op_name(ADDR)); 2078 } 2079 tn = build_op(ADDR, tn->tn_sys, 2080 expr_derive_type(tn->tn_type->t_subt, PTR), tn, NULL); 2081 } 2082 2083 /* 2084 * Expression of type function (function with return value of type T) 2085 * in rvalue-expression (pointer to function with return value 2086 * of type T) 2087 */ 2088 if (tn->tn_type->t_tspec == FUNC) 2089 tn = build_address(tn->tn_sys, tn, true); 2090 2091 /* lvalue to rvalue */ 2092 if (tn->tn_lvalue) { 2093 type_t *tp = expr_dup_type(tn->tn_type); 2094 /* C99 6.3.2.1p2 sentence 2 says to remove the qualifiers. */ 2095 tp->t_const = tp->t_volatile = false; 2096 tn = build_op(LOAD, tn->tn_sys, tp, tn, NULL); 2097 } 2098 2099 return tn; 2100 } 2101 2102 const tnode_t * 2103 before_conversion(const tnode_t *tn) 2104 { 2105 while (tn->tn_op == CVT && !tn->tn_cast) 2106 tn = tn->tn_left; 2107 return tn; 2108 } 2109 2110 /* 2111 * Most errors required by C90 are reported in struct_or_union_member(). 2112 * Here we only check for totally wrong things. 2113 */ 2114 static bool 2115 typeok_point(const tnode_t *ln, const type_t *ltp, tspec_t lt) 2116 { 2117 if (is_struct_or_union(lt)) 2118 return true; 2119 2120 if (lt == FUNC || lt == VOID || ltp->t_bitfield) 2121 goto wrong; 2122 2123 /* 2124 * Some C dialects from before C90 tolerated any lvalue on the 2125 * left-hand side of the '.' operator, allowing things like 2126 * char st[100]; st.st_mtime, assuming that the member 'st_mtime' 2127 * only occurred in a single struct; see typeok_arrow. 2128 */ 2129 if (ln->tn_lvalue) 2130 return true; 2131 2132 wrong: 2133 /* With allow_c90 we already got an error */ 2134 if (!allow_c90) 2135 /* unacceptable operand of '%s' */ 2136 error(111, op_name(POINT)); 2137 2138 return false; 2139 } 2140 2141 static bool 2142 typeok_arrow(tspec_t lt) 2143 { 2144 /* 2145 * C1978 Appendix A 14.1 says: <quote>In fact, any lvalue is allowed 2146 * before '.', and that lvalue is then assumed to have the form of 2147 * the structure of which the name of the right is a member. [...] 2148 * Such constructions are non-portable.</quote> 2149 */ 2150 if (lt == PTR || (!allow_c90 && is_integer(lt))) 2151 return true; 2152 2153 /* With allow_c90 we already got an error */ 2154 if (!allow_c90) 2155 /* unacceptable operand of '%s' */ 2156 error(111, op_name(ARROW)); 2157 return false; 2158 } 2159 2160 static bool 2161 typeok_incdec(op_t op, const tnode_t *tn, const type_t *tp) 2162 { 2163 /* operand has scalar type (checked in typeok) */ 2164 if (!tn->tn_lvalue) { 2165 if (tn->tn_op == CVT && tn->tn_cast && 2166 tn->tn_left->tn_op == LOAD) { 2167 /* a cast does not yield an lvalue */ 2168 error(163); 2169 } 2170 /* %soperand of '%s' must be lvalue */ 2171 error(114, "", op_name(op)); 2172 return false; 2173 } 2174 if (tp->t_const && allow_c90) { 2175 /* %soperand of '%s' must be modifiable lvalue */ 2176 warning(115, "", op_name(op)); 2177 } 2178 return true; 2179 } 2180 2181 static bool 2182 typeok_address(op_t op, const tnode_t *tn, const type_t *tp, tspec_t t) 2183 { 2184 if (t == ARRAY || t == FUNC) { 2185 /* ok, a warning comes later (in build_address()) */ 2186 } else if (!tn->tn_lvalue) { 2187 if (tn->tn_op == CVT && tn->tn_cast && 2188 tn->tn_left->tn_op == LOAD) { 2189 /* a cast does not yield an lvalue */ 2190 error(163); 2191 } 2192 /* %soperand of '%s' must be lvalue */ 2193 error(114, "", op_name(op)); 2194 return false; 2195 } else if (is_scalar(t)) { 2196 if (tp->t_bitfield) { 2197 /* cannot take address of bit-field */ 2198 error(112); 2199 return false; 2200 } 2201 } else if (t != STRUCT && t != UNION) { 2202 /* unacceptable operand of '%s' */ 2203 error(111, op_name(op)); 2204 return false; 2205 } 2206 if (tn->tn_op == NAME && tn->tn_sym->s_register) { 2207 /* cannot take address of register '%s' */ 2208 error(113, tn->tn_sym->s_name); 2209 return false; 2210 } 2211 return true; 2212 } 2213 2214 static bool 2215 typeok_indir(const type_t *tp, tspec_t t) 2216 { 2217 2218 if (t != PTR) { 2219 /* cannot dereference non-pointer type '%s' */ 2220 error(96, type_name(tp)); 2221 return false; 2222 } 2223 return true; 2224 } 2225 2226 static void 2227 warn_incompatible_types(op_t op, 2228 const type_t *ltp, tspec_t lt, 2229 const type_t *rtp, tspec_t rt) 2230 { 2231 bool binary = modtab[op].m_binary; 2232 2233 if (lt == VOID || (binary && rt == VOID)) { 2234 /* void type illegal in expression */ 2235 error(109); 2236 } else if (op == ASSIGN) { 2237 /* cannot assign to '%s' from '%s' */ 2238 error(171, type_name(ltp), type_name(rtp)); 2239 } else if (binary) { 2240 /* operands of '%s' have incompatible types '%s' and '%s' */ 2241 error(107, op_name(op), type_name(ltp), type_name(rtp)); 2242 } else { 2243 lint_assert(rt == NO_TSPEC); 2244 /* operand of '%s' has invalid type '%s' */ 2245 error(108, op_name(op), type_name(ltp)); 2246 } 2247 } 2248 2249 static bool 2250 typeok_plus(op_t op, 2251 const type_t *ltp, tspec_t lt, 2252 const type_t *rtp, tspec_t rt) 2253 { 2254 /* operands have scalar types (checked in typeok) */ 2255 if ((lt == PTR && !is_integer(rt)) || (rt == PTR && !is_integer(lt))) { 2256 warn_incompatible_types(op, ltp, lt, rtp, rt); 2257 return false; 2258 } 2259 return true; 2260 } 2261 2262 static bool 2263 typeok_minus(op_t op, 2264 const type_t *ltp, tspec_t lt, 2265 const type_t *rtp, tspec_t rt) 2266 { 2267 /* operands have scalar types (checked in typeok) */ 2268 if ((lt == PTR && rt != PTR && !is_integer(rt)) || 2269 (lt != PTR && rt == PTR)) { 2270 warn_incompatible_types(op, ltp, lt, rtp, rt); 2271 return false; 2272 } 2273 if (lt == PTR && rt == PTR && 2274 !types_compatible(ltp->t_subt, rtp->t_subt, true, false, NULL)) { 2275 /* illegal pointer subtraction */ 2276 error(116); 2277 } 2278 return true; 2279 } 2280 2281 static void 2282 typeok_shr(op_t op, 2283 const tnode_t *ln, tspec_t lt, 2284 const tnode_t *rn, tspec_t rt) 2285 { 2286 tspec_t olt = before_conversion(ln)->tn_type->t_tspec; 2287 tspec_t ort = before_conversion(rn)->tn_type->t_tspec; 2288 2289 /* operands have integer types (checked in typeok) */ 2290 if (pflag && !is_uinteger(olt)) { 2291 integer_constraints lc = ic_expr(ln); 2292 if (!ic_maybe_signed(ln->tn_type, &lc)) 2293 return; 2294 2295 /* 2296 * The left operand is signed. This means that 2297 * the operation is (possibly) nonportable. 2298 */ 2299 if (ln->tn_op != CON) { 2300 /* bitwise '%s' on signed value possibly nonportable */ 2301 warning(117, op_name(op)); 2302 } else if (ln->tn_val.u.integer < 0) { 2303 /* bitwise '%s' on signed value nonportable */ 2304 warning(120, op_name(op)); 2305 } 2306 } else if (allow_trad && allow_c90 && 2307 !is_uinteger(olt) && is_uinteger(ort)) { 2308 /* The left operand would become unsigned in traditional C. */ 2309 if (hflag && (ln->tn_op != CON || ln->tn_val.u.integer < 0)) { 2310 /* semantics of '%s' change in C90; use ... */ 2311 warning(118, op_name(op)); 2312 } 2313 } else if (allow_trad && allow_c90 && 2314 !is_uinteger(olt) && !is_uinteger(ort) && 2315 portable_rank_cmp(lt, rt) < 0) { 2316 /* 2317 * In traditional C, the left operand would be extended 2318 * (possibly sign-extended) and then shifted. 2319 */ 2320 if (hflag && (ln->tn_op != CON || ln->tn_val.u.integer < 0)) { 2321 /* semantics of '%s' change in C90; use ... */ 2322 warning(118, op_name(op)); 2323 } 2324 } 2325 } 2326 2327 static void 2328 typeok_shl(op_t op, tspec_t lt, tspec_t rt) 2329 { 2330 /* 2331 * C90 does not perform balancing for shift operations, 2332 * but traditional C does. If the width of the right operand 2333 * is greater than the width of the left operand, then in 2334 * traditional C the left operand would be extended to the 2335 * width of the right operand. For SHL this may result in 2336 * different results. 2337 */ 2338 if (portable_rank_cmp(lt, rt) < 0) { 2339 /* 2340 * XXX If both operands are constant, make sure 2341 * that there is really a difference between 2342 * C90 and traditional C. 2343 */ 2344 if (hflag && allow_trad && allow_c90) 2345 /* semantics of '%s' change in C90; use ... */ 2346 warning(118, op_name(op)); 2347 } 2348 } 2349 2350 static void 2351 typeok_shift(const type_t *ltp, tspec_t lt, const tnode_t *rn, tspec_t rt) 2352 { 2353 if (rn->tn_op != CON) 2354 return; 2355 2356 if (!is_uinteger(rt) && rn->tn_val.u.integer < 0) { 2357 /* negative shift */ 2358 warning(121); 2359 } else if ((uint64_t)rn->tn_val.u.integer == size_in_bits(lt)) { 2360 /* shift amount %u equals bit-size of '%s' */ 2361 warning(267, (unsigned)rn->tn_val.u.integer, type_name(ltp)); 2362 } else if ((uint64_t)rn->tn_val.u.integer > size_in_bits(lt)) { 2363 /* shift amount %llu is greater than bit-size %llu of '%s' */ 2364 warning(122, (unsigned long long)rn->tn_val.u.integer, 2365 (unsigned long long)size_in_bits(lt), 2366 tspec_name(lt)); 2367 } 2368 } 2369 2370 static bool 2371 is_typeok_eq(const tnode_t *ln, tspec_t lt, const tnode_t *rn, tspec_t rt) 2372 { 2373 if (lt == PTR && is_null_pointer(rn)) 2374 return true; 2375 if (rt == PTR && is_null_pointer(ln)) 2376 return true; 2377 return false; 2378 } 2379 2380 /* 2381 * Called if incompatible pointer types are detected. 2382 * Print an appropriate warning. 2383 */ 2384 static void 2385 warn_incompatible_pointers(op_t op, const type_t *ltp, const type_t *rtp) 2386 { 2387 lint_assert(ltp->t_tspec == PTR); 2388 lint_assert(rtp->t_tspec == PTR); 2389 2390 tspec_t lt = ltp->t_subt->t_tspec; 2391 tspec_t rt = rtp->t_subt->t_tspec; 2392 2393 if (is_struct_or_union(lt) && is_struct_or_union(rt)) { 2394 if (op == RETURN) { 2395 /* illegal structure pointer combination */ 2396 warning(244); 2397 } else { 2398 /* incompatible structure pointers: '%s' '%s' '%s' */ 2399 warning(245, type_name(ltp), 2400 op_name(op), type_name(rtp)); 2401 } 2402 } else { 2403 if (op == RETURN) { 2404 /* illegal combination of '%s' and '%s' */ 2405 warning(184, type_name(ltp), type_name(rtp)); 2406 } else { 2407 /* illegal combination of '%s' and '%s', op '%s' */ 2408 warning(124, 2409 type_name(ltp), type_name(rtp), op_name(op)); 2410 } 2411 } 2412 } 2413 2414 static void 2415 check_pointer_comparison(op_t op, const tnode_t *ln, const tnode_t *rn) 2416 { 2417 type_t *ltp = ln->tn_type, *rtp = rn->tn_type; 2418 tspec_t lst = ltp->t_subt->t_tspec, rst = rtp->t_subt->t_tspec; 2419 2420 if (lst == VOID || rst == VOID) { 2421 /* TODO: C99 behaves like C90 here. */ 2422 if ((!allow_trad && !allow_c99) && 2423 (lst == FUNC || rst == FUNC)) { 2424 /* (void *)0 is already handled in typeok() */ 2425 const char *lsts, *rsts; 2426 *(lst == FUNC ? &lsts : &rsts) = "function pointer"; 2427 *(lst == VOID ? &lsts : &rsts) = "'void *'"; 2428 /* C90 or later forbid comparison of %s with %s */ 2429 warning(274, lsts, rsts); 2430 } 2431 return; 2432 } 2433 2434 if (!types_compatible(ltp->t_subt, rtp->t_subt, true, false, NULL)) { 2435 warn_incompatible_pointers(op, ltp, rtp); 2436 return; 2437 } 2438 2439 if (lst == FUNC && rst == FUNC) { 2440 /* TODO: C99 behaves like C90 here, see C99 6.5.8p2. */ 2441 if ((!allow_trad && !allow_c99) && op != EQ && op != NE) 2442 /* pointers to functions can only be compared ... */ 2443 warning(125); 2444 } 2445 } 2446 2447 static bool 2448 typeok_compare(op_t op, 2449 const tnode_t *ln, const type_t *ltp, tspec_t lt, 2450 const tnode_t *rn, const type_t *rtp, tspec_t rt) 2451 { 2452 if (lt == PTR && rt == PTR) { 2453 check_pointer_comparison(op, ln, rn); 2454 return true; 2455 } 2456 2457 if (lt != PTR && rt != PTR) 2458 return true; 2459 2460 if (!is_integer(lt) && !is_integer(rt)) { 2461 warn_incompatible_types(op, ltp, lt, rtp, rt); 2462 return false; 2463 } 2464 2465 const char *lx = lt == PTR ? "pointer" : "integer"; 2466 const char *rx = rt == PTR ? "pointer" : "integer"; 2467 /* illegal combination of %s '%s' and %s '%s', op '%s' */ 2468 warning(123, lx, type_name(ltp), rx, type_name(rtp), op_name(op)); 2469 return true; 2470 } 2471 2472 static bool 2473 typeok_quest(tspec_t lt, const tnode_t *rn) 2474 { 2475 if (!is_scalar(lt)) { 2476 /* first operand of '?' must have scalar type */ 2477 error(170); 2478 return false; 2479 } 2480 lint_assert(before_conversion(rn)->tn_op == COLON); 2481 return true; 2482 } 2483 2484 static void 2485 typeok_colon_pointer(const type_t *ltp, const type_t *rtp) 2486 { 2487 type_t *lstp = ltp->t_subt; 2488 type_t *rstp = rtp->t_subt; 2489 tspec_t lst = lstp->t_tspec; 2490 tspec_t rst = rstp->t_tspec; 2491 2492 if ((lst == VOID && rst == FUNC) || (lst == FUNC && rst == VOID)) { 2493 /* (void *)0 is handled in typeok_colon */ 2494 /* TODO: C99 behaves like C90 here. */ 2495 if (!allow_trad && !allow_c99) 2496 /* conversion of %s to %s requires a cast, op %s */ 2497 warning(305, "function pointer", "'void *'", 2498 op_name(COLON)); 2499 return; 2500 } 2501 2502 if (pointer_types_are_compatible(lstp, rstp, true)) 2503 return; 2504 if (!types_compatible(lstp, rstp, true, false, NULL)) 2505 warn_incompatible_pointers(COLON, ltp, rtp); 2506 } 2507 2508 static bool 2509 typeok_colon(const tnode_t *ln, const type_t *ltp, tspec_t lt, 2510 const tnode_t *rn, const type_t *rtp, tspec_t rt) 2511 { 2512 2513 if (is_arithmetic(lt) && is_arithmetic(rt)) 2514 return true; 2515 if (lt == BOOL && rt == BOOL) 2516 return true; 2517 2518 if (lt == STRUCT && rt == STRUCT && ltp->t_sou == rtp->t_sou) 2519 return true; 2520 if (lt == UNION && rt == UNION && ltp->t_sou == rtp->t_sou) 2521 return true; 2522 2523 if (lt == PTR && is_null_pointer(rn)) 2524 return true; 2525 if (rt == PTR && is_null_pointer(ln)) 2526 return true; 2527 2528 if ((lt == PTR && is_integer(rt)) || (is_integer(lt) && rt == PTR)) { 2529 const char *lx = lt == PTR ? "pointer" : "integer"; 2530 const char *rx = rt == PTR ? "pointer" : "integer"; 2531 /* illegal combination of %s '%s' and %s '%s', op '%s' */ 2532 warning(123, lx, type_name(ltp), 2533 rx, type_name(rtp), op_name(COLON)); 2534 return true; 2535 } 2536 2537 if (lt == VOID || rt == VOID) { 2538 if (lt != VOID || rt != VOID) 2539 /* incompatible types '%s' and '%s' in conditional */ 2540 warning(126, type_name(ltp), type_name(rtp)); 2541 return true; 2542 } 2543 2544 if (lt == PTR && rt == PTR) { 2545 typeok_colon_pointer(ltp, rtp); 2546 return true; 2547 } 2548 2549 /* incompatible types '%s' and '%s' in conditional */ 2550 error(126, type_name(ltp), type_name(rtp)); 2551 return false; 2552 } 2553 2554 /* 2555 * Returns true if the given structure or union has a constant member 2556 * (maybe recursively). 2557 */ 2558 static bool 2559 has_constant_member(const type_t *tp) 2560 { 2561 lint_assert(is_struct_or_union(tp->t_tspec)); 2562 2563 for (sym_t *m = tp->t_sou->sou_first_member; 2564 m != NULL; m = m->s_next) { 2565 const type_t *mtp = m->s_type; 2566 if (mtp->t_const) 2567 return true; 2568 if (is_struct_or_union(mtp->t_tspec) && 2569 has_constant_member(mtp)) 2570 return true; 2571 } 2572 return false; 2573 } 2574 2575 static bool 2576 typeok_assign(op_t op, const tnode_t *ln, const type_t *ltp, tspec_t lt) 2577 { 2578 if (op == RETURN || op == INIT || op == FARG) 2579 return true; 2580 2581 if (!ln->tn_lvalue) { 2582 if (ln->tn_op == CVT && ln->tn_cast && 2583 ln->tn_left->tn_op == LOAD) { 2584 /* a cast does not yield an lvalue */ 2585 error(163); 2586 } 2587 /* %soperand of '%s' must be lvalue */ 2588 error(114, "left ", op_name(op)); 2589 return false; 2590 } else if (ltp->t_const 2591 || (is_struct_or_union(lt) && has_constant_member(ltp))) { 2592 if (allow_c90) 2593 /* %soperand of '%s' must be modifiable lvalue */ 2594 warning(115, "left ", op_name(op)); 2595 } 2596 return true; 2597 } 2598 2599 /* Check the types using the information from modtab[]. */ 2600 static bool 2601 typeok_scalar(op_t op, const mod_t *mp, 2602 const type_t *ltp, tspec_t lt, 2603 const type_t *rtp, tspec_t rt) 2604 { 2605 if (mp->m_takes_bool && lt == BOOL && rt == BOOL) 2606 return true; 2607 if (mp->m_requires_integer) { 2608 if (!is_integer(lt) || (mp->m_binary && !is_integer(rt))) { 2609 warn_incompatible_types(op, ltp, lt, rtp, rt); 2610 return false; 2611 } 2612 } else if (mp->m_requires_integer_or_complex) { 2613 if ((!is_integer(lt) && !is_complex(lt)) || 2614 (mp->m_binary && (!is_integer(rt) && !is_complex(rt)))) { 2615 warn_incompatible_types(op, ltp, lt, rtp, rt); 2616 return false; 2617 } 2618 } else if (mp->m_requires_scalar) { 2619 if (!is_scalar(lt) || (mp->m_binary && !is_scalar(rt))) { 2620 warn_incompatible_types(op, ltp, lt, rtp, rt); 2621 return false; 2622 } 2623 } else if (mp->m_requires_arith) { 2624 if (!is_arithmetic(lt) || 2625 (mp->m_binary && !is_arithmetic(rt))) { 2626 warn_incompatible_types(op, ltp, lt, rtp, rt); 2627 return false; 2628 } 2629 } 2630 return true; 2631 } 2632 2633 static void 2634 check_assign_void_pointer(op_t op, int arg, 2635 tspec_t lt, tspec_t lst, 2636 tspec_t rt, tspec_t rst) 2637 { 2638 2639 if (!(lt == PTR && rt == PTR && (lst == VOID || rst == VOID))) 2640 return; 2641 /* two pointers, at least one pointer to void */ 2642 2643 /* TODO: C99 behaves like C90 here. */ 2644 if (!((!allow_trad && !allow_c99) && (lst == FUNC || rst == FUNC))) 2645 return; 2646 /* comb. of ptr to func and ptr to void */ 2647 2648 const char *lts, *rts; 2649 *(lst == FUNC ? <s : &rts) = "function pointer"; 2650 *(lst == VOID ? <s : &rts) = "'void *'"; 2651 2652 switch (op) { 2653 case INIT: 2654 case RETURN: 2655 /* conversion of %s to %s requires a cast */ 2656 warning(303, rts, lts); 2657 break; 2658 case FARG: 2659 /* conversion of %s to %s requires a cast, arg #%d */ 2660 warning(304, rts, lts, arg); 2661 break; 2662 default: 2663 /* conversion of %s to %s requires a cast, op %s */ 2664 warning(305, rts, lts, op_name(op)); 2665 break; 2666 } 2667 } 2668 2669 static bool 2670 is_direct_function_call(const tnode_t *tn, const char **out_name) 2671 { 2672 2673 if (!(tn->tn_op == CALL && 2674 tn->tn_left->tn_op == ADDR && 2675 tn->tn_left->tn_left->tn_op == NAME)) 2676 return false; 2677 2678 *out_name = tn->tn_left->tn_left->tn_sym->s_name; 2679 return true; 2680 } 2681 2682 static bool 2683 is_unconst_function(const char *name) 2684 { 2685 2686 return strcmp(name, "memchr") == 0 || 2687 strcmp(name, "strchr") == 0 || 2688 strcmp(name, "strpbrk") == 0 || 2689 strcmp(name, "strrchr") == 0 || 2690 strcmp(name, "strstr") == 0; 2691 } 2692 2693 static bool 2694 is_const_char_pointer(const tnode_t *tn) 2695 { 2696 /* 2697 * For traditional reasons, C99 6.4.5p5 defines that string literals 2698 * have type 'char[]'. They are often implicitly converted to 2699 * 'char *', for example when they are passed as function arguments. 2700 * 2701 * C99 6.4.5p6 further defines that modifying a string that is 2702 * constructed from a string literal invokes undefined behavior. 2703 * 2704 * Out of these reasons, string literals are treated as 'effectively 2705 * const' here. 2706 */ 2707 if (tn->tn_op == CVT && 2708 tn->tn_left->tn_op == ADDR && 2709 tn->tn_left->tn_left->tn_op == STRING) 2710 return true; 2711 2712 const type_t *tp = before_conversion(tn)->tn_type; 2713 return tp->t_tspec == PTR && 2714 tp->t_subt->t_tspec == CHAR && 2715 tp->t_subt->t_const; 2716 } 2717 2718 static bool 2719 is_first_arg_const_char_pointer(const tnode_t *tn) 2720 { 2721 lint_assert(has_operands(tn)); 2722 const tnode_t *an = tn->tn_right; 2723 if (an == NULL) 2724 return false; 2725 2726 while (tn_ck_right(an) != NULL) 2727 an = an->tn_right; 2728 return is_const_char_pointer(an->tn_left); 2729 } 2730 2731 static bool 2732 is_const_pointer(const tnode_t *tn) 2733 { 2734 const type_t *tp = before_conversion(tn)->tn_type; 2735 return tp->t_tspec == PTR && tp->t_subt->t_const; 2736 } 2737 2738 static bool 2739 is_second_arg_const_pointer(const tnode_t *tn) 2740 { 2741 const tnode_t *an = tn_ck_right(tn); 2742 if (an == NULL || tn_ck_right(an) == NULL) 2743 return false; 2744 2745 while (tn_ck_right(an->tn_right) != NULL) 2746 an = an->tn_right; 2747 return is_const_pointer(an->tn_left); 2748 } 2749 2750 static void 2751 check_unconst_function(const type_t *lstp, const tnode_t *rn) 2752 { 2753 const char *function_name; 2754 2755 if (lstp->t_tspec == CHAR && !lstp->t_const && 2756 is_direct_function_call(rn, &function_name) && 2757 is_unconst_function(function_name) && 2758 is_first_arg_const_char_pointer(rn)) { 2759 /* call to '%s' effectively discards 'const' from argument */ 2760 warning(346, function_name); 2761 } 2762 2763 if (!lstp->t_const && 2764 is_direct_function_call(rn, &function_name) && 2765 strcmp(function_name, "bsearch") == 0 && 2766 is_second_arg_const_pointer(rn)) { 2767 /* call to '%s' effectively discards 'const' from argument */ 2768 warning(346, function_name); 2769 } 2770 } 2771 2772 static bool 2773 check_assign_void_pointer_compat(op_t op, int arg, 2774 const type_t *const ltp, tspec_t const lt, 2775 const type_t *const lstp, tspec_t const lst, 2776 const tnode_t *const rn, 2777 const type_t *const rtp, tspec_t const rt, 2778 const type_t *const rstp, tspec_t const rst) 2779 { 2780 if (!(lt == PTR && rt == PTR && (lst == VOID || rst == VOID || 2781 types_compatible(lstp, rstp, 2782 true, false, NULL)))) 2783 return false; 2784 2785 /* compatible pointer types (qualifiers ignored) */ 2786 if (allow_c90 && 2787 ((!lstp->t_const && rstp->t_const) || 2788 (!lstp->t_volatile && rstp->t_volatile))) { 2789 /* left side has not all qualifiers of right */ 2790 switch (op) { 2791 case INIT: 2792 case RETURN: 2793 /* incompatible pointer types to '%s' and '%s' */ 2794 warning(182, type_name(lstp), type_name(rstp)); 2795 break; 2796 case FARG: 2797 /* converting '%s' to incompatible '%s' ... */ 2798 warning(153, 2799 type_name(rtp), type_name(ltp), arg); 2800 break; 2801 default: 2802 /* operands of '%s' have incompatible pointer ... */ 2803 warning(128, op_name(op), 2804 type_name(lstp), type_name(rstp)); 2805 break; 2806 } 2807 } 2808 2809 if (allow_c90) 2810 check_unconst_function(lstp, rn); 2811 2812 return true; 2813 } 2814 2815 static bool 2816 check_assign_pointer_integer(op_t op, int arg, 2817 const type_t *const ltp, tspec_t const lt, 2818 const type_t *const rtp, tspec_t const rt) 2819 { 2820 2821 if (!((lt == PTR && is_integer(rt)) || (is_integer(lt) && rt == PTR))) 2822 return false; 2823 2824 const char *lx = lt == PTR ? "pointer" : "integer"; 2825 const char *rx = rt == PTR ? "pointer" : "integer"; 2826 2827 switch (op) { 2828 case INIT: 2829 case RETURN: 2830 /* illegal combination of %s '%s' and %s '%s' */ 2831 warning(183, lx, type_name(ltp), rx, type_name(rtp)); 2832 break; 2833 case FARG: 2834 /* illegal combination of %s '%s' and %s '%s', arg #%d */ 2835 warning(154, 2836 lx, type_name(ltp), rx, type_name(rtp), arg); 2837 break; 2838 default: 2839 /* illegal combination of %s '%s' and %s '%s', op '%s' */ 2840 warning(123, 2841 lx, type_name(ltp), rx, type_name(rtp), op_name(op)); 2842 break; 2843 } 2844 return true; 2845 } 2846 2847 static bool 2848 check_assign_pointer(op_t op, int arg, 2849 const type_t *ltp, tspec_t lt, 2850 const type_t *rtp, tspec_t rt) 2851 { 2852 if (!(lt == PTR && rt == PTR)) 2853 return false; 2854 2855 if (op == FARG) 2856 /* converting '%s' to incompatible '%s' for ... */ 2857 warning(153, type_name(rtp), type_name(ltp), arg); 2858 else 2859 warn_incompatible_pointers(op, ltp, rtp); 2860 return true; 2861 } 2862 2863 static void 2864 warn_assign(op_t op, int arg, 2865 const type_t *ltp, tspec_t lt, 2866 const type_t *rtp, tspec_t rt) 2867 { 2868 switch (op) { 2869 case INIT: 2870 /* cannot initialize '%s' from '%s' */ 2871 error(185, type_name(ltp), type_name(rtp)); 2872 break; 2873 case RETURN: 2874 /* function has return type '%s' but returns '%s' */ 2875 error(211, type_name(ltp), type_name(rtp)); 2876 break; 2877 case FARG: 2878 /* passing '%s' to incompatible '%s', arg #%d */ 2879 warning(155, type_name(rtp), type_name(ltp), arg); 2880 break; 2881 default: 2882 warn_incompatible_types(op, ltp, lt, rtp, rt); 2883 break; 2884 } 2885 } 2886 2887 /* 2888 * Checks type compatibility for ASSIGN, INIT, FARG and RETURN 2889 * and prints warnings/errors if necessary. 2890 * Returns whether the types are (almost) compatible. 2891 */ 2892 static bool 2893 check_assign_types_compatible(op_t op, int arg, 2894 const tnode_t *ln, const tnode_t *rn) 2895 { 2896 tspec_t lt, rt, lst = NO_TSPEC, rst = NO_TSPEC; 2897 type_t *ltp, *rtp, *lstp = NULL, *rstp = NULL; 2898 2899 if ((lt = (ltp = ln->tn_type)->t_tspec) == PTR) 2900 lst = (lstp = ltp->t_subt)->t_tspec; 2901 if ((rt = (rtp = rn->tn_type)->t_tspec) == PTR) 2902 rst = (rstp = rtp->t_subt)->t_tspec; 2903 2904 if (lt == BOOL && is_scalar(rt)) /* C99 6.3.1.2 */ 2905 return true; 2906 2907 if (is_arithmetic(lt) && (is_arithmetic(rt) || rt == BOOL)) 2908 return true; 2909 2910 if (is_struct_or_union(lt) && is_struct_or_union(rt)) 2911 /* both are struct or union */ 2912 return ltp->t_sou == rtp->t_sou; 2913 2914 /* a null pointer may be assigned to any pointer */ 2915 if (lt == PTR && is_null_pointer(rn)) { 2916 if (is_integer(rn->tn_type->t_tspec)) 2917 /* implicit conversion from integer 0 to pointer ... */ 2918 query_message(15, type_name(ltp)); 2919 return true; 2920 } 2921 2922 check_assign_void_pointer(op, arg, lt, lst, rt, rst); 2923 2924 if (check_assign_void_pointer_compat(op, arg, 2925 ltp, lt, lstp, lst, rn, rtp, rt, rstp, rst)) 2926 return true; 2927 2928 if (check_assign_pointer_integer(op, arg, ltp, lt, rtp, rt)) 2929 return true; 2930 2931 if (check_assign_pointer(op, arg, ltp, lt, rtp, rt)) 2932 return true; 2933 2934 warn_assign(op, arg, ltp, lt, rtp, rt); 2935 return false; 2936 } 2937 2938 static bool 2939 has_side_effect(const tnode_t *tn) /* NOLINT(misc-no-recursion) */ 2940 { 2941 op_t op = tn->tn_op; 2942 2943 if (modtab[op].m_has_side_effect) 2944 return true; 2945 2946 if (op == CVT && tn->tn_type->t_tspec == VOID) 2947 return has_side_effect(tn->tn_left); 2948 2949 /* XXX: Why not has_side_effect(tn->tn_left) as well? */ 2950 if (op == LOGAND || op == LOGOR) 2951 return has_side_effect(tn->tn_right); 2952 2953 /* XXX: Why not has_side_effect(tn->tn_left) as well? */ 2954 if (op == QUEST) 2955 return has_side_effect(tn->tn_right); 2956 2957 if (op == COLON || op == COMMA) { 2958 return has_side_effect(tn->tn_left) || 2959 has_side_effect(tn->tn_right); 2960 } 2961 2962 return false; 2963 } 2964 2965 static bool 2966 is_void_cast(const tnode_t *tn) 2967 { 2968 2969 return tn->tn_op == CVT && tn->tn_cast && 2970 tn->tn_type->t_tspec == VOID; 2971 } 2972 2973 static bool 2974 is_local_symbol(const tnode_t *tn) 2975 { 2976 2977 return tn->tn_op == LOAD && 2978 tn->tn_left->tn_op == NAME && 2979 tn->tn_left->tn_sym->s_scl == AUTO; 2980 } 2981 2982 static bool 2983 is_int_constant_zero(const tnode_t *tn) 2984 { 2985 2986 return tn->tn_op == CON && 2987 tn->tn_type->t_tspec == INT && 2988 tn->tn_val.u.integer == 0; 2989 } 2990 2991 static void 2992 check_null_effect(const tnode_t *tn) 2993 { 2994 2995 if (hflag && 2996 !has_side_effect(tn) && 2997 !(is_void_cast(tn) && is_local_symbol(tn->tn_left)) && 2998 !(is_void_cast(tn) && is_int_constant_zero(tn->tn_left))) { 2999 /* expression has null effect */ 3000 warning(129); 3001 } 3002 } 3003 3004 /* 3005 * Check the types for specific operators and type combinations. 3006 * 3007 * At this point, the operands already conform to the type requirements of 3008 * the operator, such as being integer, floating or scalar. 3009 */ 3010 static bool 3011 typeok_op(op_t op, int arg, 3012 const tnode_t *ln, const type_t *ltp, tspec_t lt, 3013 const tnode_t *rn, const type_t *rtp, tspec_t rt) 3014 { 3015 switch (op) { 3016 case ARROW: 3017 return typeok_arrow(lt); 3018 case POINT: 3019 return typeok_point(ln, ltp, lt); 3020 case INCBEF: 3021 case DECBEF: 3022 case INCAFT: 3023 case DECAFT: 3024 return typeok_incdec(op, ln, ltp); 3025 case INDIR: 3026 return typeok_indir(ltp, lt); 3027 case ADDR: 3028 return typeok_address(op, ln, ltp, lt); 3029 case PLUS: 3030 return typeok_plus(op, ltp, lt, rtp, rt); 3031 case MINUS: 3032 return typeok_minus(op, ltp, lt, rtp, rt); 3033 case SHL: 3034 typeok_shl(op, lt, rt); 3035 goto shift; 3036 case SHR: 3037 typeok_shr(op, ln, lt, rn, rt); 3038 shift: 3039 typeok_shift(ltp, lt, rn, rt); 3040 break; 3041 case LT: 3042 case LE: 3043 case GT: 3044 case GE: 3045 compare: 3046 return typeok_compare(op, ln, ltp, lt, rn, rtp, rt); 3047 case EQ: 3048 case NE: 3049 if (is_typeok_eq(ln, lt, rn, rt)) 3050 break; 3051 goto compare; 3052 case QUEST: 3053 return typeok_quest(lt, rn); 3054 case COLON: 3055 return typeok_colon(ln, ltp, lt, rn, rtp, rt); 3056 case ASSIGN: 3057 case INIT: 3058 case FARG: 3059 case RETURN: 3060 if (!check_assign_types_compatible(op, arg, ln, rn)) 3061 return false; 3062 goto assign; 3063 case MULASS: 3064 case DIVASS: 3065 case MODASS: 3066 goto assign; 3067 case ADDASS: 3068 case SUBASS: 3069 if ((lt == PTR && !is_integer(rt)) || rt == PTR) { 3070 warn_incompatible_types(op, ltp, lt, rtp, rt); 3071 return false; 3072 } 3073 goto assign; 3074 case SHLASS: 3075 goto assign; 3076 case SHRASS: 3077 if (pflag && !is_uinteger(lt) && 3078 !(!allow_c90 && is_uinteger(rt))) { 3079 /* bitwise '%s' on signed value possibly nonportable */ 3080 warning(117, op_name(op)); 3081 } 3082 goto assign; 3083 case ANDASS: 3084 case XORASS: 3085 case ORASS: 3086 assign: 3087 return typeok_assign(op, ln, ltp, lt); 3088 case COMMA: 3089 if (!modtab[ln->tn_op].m_has_side_effect) 3090 check_null_effect(ln); 3091 break; 3092 default: 3093 break; 3094 } 3095 return true; 3096 } 3097 3098 /* Prints a warning if a strange operator is used on an enum type. */ 3099 static void 3100 check_bad_enum_operation(op_t op, const tnode_t *ln, const tnode_t *rn) 3101 { 3102 3103 if (!eflag) 3104 return; 3105 3106 /* Allow enum in array indices. */ 3107 if (op == PLUS && 3108 ((ln->tn_type->t_is_enum && rn->tn_type->t_tspec == PTR) || 3109 (rn->tn_type->t_is_enum && ln->tn_type->t_tspec == PTR))) { 3110 return; 3111 } 3112 3113 /* dubious operation '%s' on enum */ 3114 warning(241, op_name(op)); 3115 } 3116 3117 /* Prints a warning if an operator is applied to two different enum types. */ 3118 static void 3119 check_enum_type_mismatch(op_t op, int arg, const tnode_t *ln, const tnode_t *rn) 3120 { 3121 const mod_t *mp = &modtab[op]; 3122 3123 if (ln->tn_type->t_enum != rn->tn_type->t_enum) { 3124 switch (op) { 3125 case INIT: 3126 /* enum type mismatch between '%s' and '%s' in ... */ 3127 warning(210, 3128 type_name(ln->tn_type), type_name(rn->tn_type)); 3129 break; 3130 case FARG: 3131 /* function expects '%s', passing '%s' for arg #%d */ 3132 warning(156, 3133 type_name(ln->tn_type), type_name(rn->tn_type), 3134 arg); 3135 break; 3136 case RETURN: 3137 /* function has return type '%s' but returns '%s' */ 3138 warning(211, 3139 type_name(ln->tn_type), type_name(rn->tn_type)); 3140 break; 3141 default: 3142 /* enum type mismatch: '%s' '%s' '%s' */ 3143 warning(130, type_name(ln->tn_type), op_name(op), 3144 type_name(rn->tn_type)); 3145 break; 3146 } 3147 } else if (Pflag && eflag && mp->m_comparison && op != EQ && op != NE) 3148 /* operator '%s' assumes that '%s' is ordered */ 3149 warning(243, op_name(op), type_name(ln->tn_type)); 3150 } 3151 3152 /* Prints a warning if the operands mix between enum and integer. */ 3153 static void 3154 check_enum_int_mismatch(op_t op, int arg, const tnode_t *ln, const tnode_t *rn) 3155 { 3156 3157 if (!eflag) 3158 return; 3159 3160 switch (op) { 3161 case INIT: 3162 /* 3163 * Initialization with 0 is allowed. Otherwise, all implicit 3164 * initializations would need to be warned upon as well. 3165 */ 3166 if (!rn->tn_type->t_is_enum && rn->tn_op == CON && 3167 is_integer(rn->tn_type->t_tspec) && 3168 rn->tn_val.u.integer == 0) { 3169 return; 3170 } 3171 /* initialization of '%s' with '%s' */ 3172 warning(277, type_name(ln->tn_type), type_name(rn->tn_type)); 3173 break; 3174 case FARG: 3175 /* combination of '%s' and '%s', arg #%d */ 3176 warning(278, 3177 type_name(ln->tn_type), type_name(rn->tn_type), arg); 3178 break; 3179 case RETURN: 3180 /* combination of '%s' and '%s' in return */ 3181 warning(279, type_name(ln->tn_type), type_name(rn->tn_type)); 3182 break; 3183 default: 3184 /* combination of '%s' and '%s', op '%s' */ 3185 warning(242, type_name(ln->tn_type), type_name(rn->tn_type), 3186 op_name(op)); 3187 break; 3188 } 3189 } 3190 3191 static void 3192 typeok_enum(op_t op, const mod_t *mp, int arg, 3193 const tnode_t *ln, const type_t *ltp, 3194 const tnode_t *rn, const type_t *rtp) 3195 { 3196 if (mp->m_bad_on_enum && 3197 (ltp->t_is_enum || (mp->m_binary && rtp->t_is_enum))) { 3198 check_bad_enum_operation(op, ln, rn); 3199 } else if (mp->m_valid_on_enum && 3200 (ltp->t_is_enum && rtp != NULL && rtp->t_is_enum)) { 3201 check_enum_type_mismatch(op, arg, ln, rn); 3202 } else if (mp->m_valid_on_enum && 3203 (ltp->t_is_enum || (rtp != NULL && rtp->t_is_enum))) { 3204 check_enum_int_mismatch(op, arg, ln, rn); 3205 } 3206 } 3207 3208 /* Perform most type checks. Return whether the types are ok. */ 3209 bool 3210 typeok(op_t op, int arg, const tnode_t *ln, const tnode_t *rn) 3211 { 3212 3213 const mod_t *mp = &modtab[op]; 3214 3215 type_t *ltp = ln->tn_type; 3216 tspec_t lt = ltp->t_tspec; 3217 3218 type_t *rtp = mp->m_binary ? rn->tn_type : NULL; 3219 tspec_t rt = mp->m_binary ? rtp->t_tspec : NO_TSPEC; 3220 3221 if (Tflag && !typeok_scalar_strict_bool(op, mp, arg, ln, rn)) 3222 return false; 3223 if (!typeok_scalar(op, mp, ltp, lt, rtp, rt)) 3224 return false; 3225 3226 if (!typeok_op(op, arg, ln, ltp, lt, rn, rtp, rt)) 3227 return false; 3228 3229 typeok_enum(op, mp, arg, ln, ltp, rn, rtp); 3230 return true; 3231 } 3232 3233 /* In traditional C, keep unsigned and promote FLOAT to DOUBLE. */ 3234 static tspec_t 3235 promote_trad(tspec_t t) 3236 { 3237 3238 if (t == UCHAR || t == USHORT) 3239 return UINT; 3240 if (t == CHAR || t == SCHAR || t == SHORT) 3241 return INT; 3242 if (t == FLOAT) 3243 return DOUBLE; 3244 if (t == ENUM) 3245 return INT; 3246 return t; 3247 } 3248 3249 /* 3250 * C99 6.3.1.1p2 requires for types with lower rank than int that "If an int 3251 * can represent all the values of the original type, the value is converted 3252 * to an int; otherwise it is converted to an unsigned int", and that "All 3253 * other types are unchanged by the integer promotions". 3254 */ 3255 static tspec_t 3256 promote_c90(const tnode_t *tn, tspec_t t, bool farg) 3257 { 3258 if (tn->tn_type->t_bitfield) { 3259 unsigned int width = tn->tn_type->t_bit_field_width; 3260 unsigned int int_width = size_in_bits(INT); 3261 // XXX: What about _Bool bit-fields, since C99? 3262 if (width < int_width) 3263 return INT; 3264 if (width == int_width) 3265 return is_uinteger(t) ? UINT : INT; 3266 return t; 3267 } 3268 3269 if (t == CHAR || t == SCHAR) 3270 return INT; 3271 if (t == UCHAR) 3272 return size_in_bits(CHAR) < size_in_bits(INT) ? INT : UINT; 3273 if (t == SHORT) 3274 return INT; 3275 if (t == USHORT) 3276 return size_in_bits(SHORT) < size_in_bits(INT) ? INT : UINT; 3277 if (t == ENUM) 3278 return INT; 3279 if (farg && t == FLOAT) 3280 return DOUBLE; 3281 return t; 3282 } 3283 3284 /* 3285 * Performs the "integer promotions" (C99 6.3.1.1p2), which convert small 3286 * integer types to either int or unsigned int. 3287 * 3288 * If allow_c90 is unset or the operand is a function argument with no type 3289 * information (no prototype or variable # of args), converts float to double. 3290 */ 3291 tnode_t * 3292 promote(op_t op, bool farg, tnode_t *tn) 3293 { 3294 3295 tspec_t ot = tn->tn_type->t_tspec; 3296 if (!is_arithmetic(ot)) 3297 return tn; 3298 3299 tspec_t nt = allow_c90 ? promote_c90(tn, ot, farg) : promote_trad(ot); 3300 if (nt == ot) 3301 return tn; 3302 3303 type_t *ntp = expr_dup_type(tn->tn_type); 3304 ntp->t_tspec = nt; 3305 /* 3306 * Keep t_is_enum even though t_tspec gets converted from 3307 * ENUM to INT, so we are later able to check compatibility 3308 * of enum types. 3309 */ 3310 return convert(op, 0, ntp, tn); 3311 } 3312 3313 static void 3314 convert_integer_from_floating(op_t op, const type_t *tp, const tnode_t *tn) 3315 { 3316 3317 if (op == CVT) 3318 /* cast from floating point '%s' to integer '%s' */ 3319 query_message(2, type_name(tn->tn_type), type_name(tp)); 3320 else 3321 /* implicit conversion from floating point '%s' to ... */ 3322 query_message(1, type_name(tn->tn_type), type_name(tp)); 3323 } 3324 3325 static bool 3326 should_warn_about_prototype_conversion(tspec_t nt, 3327 tspec_t ot, const tnode_t *ptn) 3328 { 3329 3330 if (nt == ot) 3331 return false; 3332 3333 if (nt == ENUM && ot == INT) 3334 return false; 3335 3336 if (is_floating(nt) != is_floating(ot) || 3337 portable_rank_cmp(nt, ot) != 0) { 3338 /* representation and/or width change */ 3339 if (!is_integer(ot)) 3340 return true; 3341 /* 3342 * XXX: Investigate whether this rule makes sense; see 3343 * tests/usr.bin/xlint/lint1/platform_long.c. 3344 */ 3345 return portable_rank_cmp(ot, INT) > 0; 3346 } 3347 3348 if (!hflag) 3349 return false; 3350 3351 /* 3352 * If the types differ only in sign and the argument has the same 3353 * representation in both types, print no warning. 3354 */ 3355 if (ptn->tn_op == CON && is_integer(nt) && 3356 signed_type(nt) == signed_type(ot) && 3357 !msb(ptn->tn_val.u.integer, ot)) 3358 return false; 3359 3360 return true; 3361 } 3362 3363 /* 3364 * Warn if a prototype causes a type conversion that is different from what 3365 * would happen to the same argument in the absence of a prototype. This 3366 * check is intended for code that needs to stay compatible with pre-C90 C. 3367 * 3368 * Errors/warnings about illegal type combinations are already printed 3369 * in check_assign_types_compatible(). 3370 */ 3371 static void 3372 check_prototype_conversion(int arg, tspec_t nt, tspec_t ot, type_t *tp, 3373 tnode_t *tn) 3374 { 3375 3376 if (!is_arithmetic(nt) || !is_arithmetic(ot)) 3377 return; 3378 3379 /* 3380 * If the type of the formal parameter is char/short, a warning 3381 * would be useless, because functions declared the old style 3382 * can't expect char/short arguments. 3383 */ 3384 if (nt == CHAR || nt == SCHAR || nt == UCHAR || 3385 nt == SHORT || nt == USHORT) 3386 return; 3387 3388 /* apply the default promotion */ 3389 tnode_t *ptn = promote(NOOP, true, tn); 3390 ot = ptn->tn_type->t_tspec; 3391 3392 if (should_warn_about_prototype_conversion(nt, ot, ptn)) { 3393 /* argument %d is converted from '%s' to '%s' ... */ 3394 warning(259, arg, type_name(tn->tn_type), type_name(tp)); 3395 } 3396 } 3397 3398 /* 3399 * When converting a large integer type to a small integer type, in some 3400 * cases the value of the actual expression is further restricted than the 3401 * type bounds, such as in (expr & 0xFF) or (expr % 100) or (expr >> 24). 3402 */ 3403 static bool 3404 can_represent(const type_t *tp, const tnode_t *tn) 3405 { 3406 3407 debug_step("%s: type '%s'", __func__, type_name(tp)); 3408 debug_node(tn); 3409 3410 uint64_t nmask = value_bits(width_in_bits(tp)); 3411 if (!is_uinteger(tp->t_tspec)) 3412 nmask >>= 1; 3413 3414 integer_constraints c = ic_expr(tn); 3415 if ((~c.bclr & ~nmask) == 0) 3416 return true; 3417 3418 integer_constraints tpc = ic_any(tp); 3419 if (is_uinteger(tp->t_tspec) 3420 ? tpc.umin <= c.umin && tpc.umax >= c.umax 3421 : tpc.smin <= c.smin && tpc.smax >= c.smax) 3422 return true; 3423 3424 return false; 3425 } 3426 3427 static bool 3428 should_warn_about_integer_conversion(const type_t *ntp, tspec_t nt, 3429 const tnode_t *otn, tspec_t ot) 3430 { 3431 3432 // XXX: The portable_rank_cmp aims at portable mode, independent of the 3433 // current platform, while can_represent acts on the actual type sizes 3434 // from the current platform. This mix is inconsistent, but anything 3435 // else would make the exact conditions too complicated to grasp. 3436 if (aflag > 0 && portable_rank_cmp(nt, ot) < 0) { 3437 if (ot == LONG || ot == ULONG 3438 || ot == LLONG || ot == ULLONG 3439 #ifdef INT128_SIZE 3440 || ot == INT128 || ot == UINT128 3441 #endif 3442 || aflag > 1) 3443 return !can_represent(ntp, otn); 3444 } 3445 return false; 3446 } 3447 3448 static void 3449 convert_integer_from_integer(op_t op, int arg, tspec_t nt, tspec_t ot, 3450 type_t *tp, tnode_t *tn) 3451 { 3452 3453 if (tn->tn_op == CON) 3454 return; 3455 3456 if (op == CVT) 3457 return; 3458 3459 if (Pflag && pflag && aflag > 0 && 3460 portable_rank_cmp(nt, ot) > 0 && 3461 is_uinteger(nt) != is_uinteger(ot)) { 3462 if (op == FARG) { 3463 /* conversion to '%s' may sign-extend ... */ 3464 warning(297, type_name(tp), arg); 3465 } else { 3466 /* conversion to '%s' may sign-extend ... */ 3467 warning(131, type_name(tp)); 3468 } 3469 } 3470 3471 if (Pflag && portable_rank_cmp(nt, ot) > 0 && 3472 (tn->tn_op == PLUS || tn->tn_op == MINUS || tn->tn_op == MULT || 3473 tn->tn_op == SHL)) { 3474 /* suggest cast from '%s' to '%s' on op '%s' to ... */ 3475 warning(324, type_name(gettyp(ot)), type_name(tp), 3476 op_name(tn->tn_op)); 3477 } 3478 3479 if (should_warn_about_integer_conversion(tp, nt, tn, ot)) { 3480 if (op == FARG) { 3481 /* conversion from '%s' to '%s' may lose ... */ 3482 warning(298, 3483 type_name(tn->tn_type), type_name(tp), arg); 3484 } else { 3485 /* conversion from '%s' to '%s' may lose accuracy */ 3486 warning(132, 3487 type_name(tn->tn_type), type_name(tp)); 3488 } 3489 } 3490 3491 if (any_query_enabled && is_uinteger(nt) != is_uinteger(ot)) 3492 /* implicit conversion changes sign from '%s' to '%s' */ 3493 query_message(3, type_name(tn->tn_type), type_name(tp)); 3494 } 3495 3496 static void 3497 convert_integer_from_pointer(op_t op, tspec_t nt, type_t *tp, tnode_t *tn) 3498 { 3499 3500 if (tn->tn_op == CON) 3501 return; 3502 if (op != CVT) 3503 return; /* We already got an error. */ 3504 if (portable_rank_cmp(nt, PTR) >= 0) 3505 return; 3506 3507 if (pflag && size_in_bits(nt) >= size_in_bits(PTR)) { 3508 /* conversion of pointer to '%s' may lose bits */ 3509 warning(134, type_name(tp)); 3510 } else { 3511 /* conversion of pointer to '%s' loses bits */ 3512 warning(133, type_name(tp)); 3513 } 3514 } 3515 3516 static bool 3517 struct_starts_with(const type_t *struct_tp, const type_t *member_tp) 3518 { 3519 3520 return struct_tp->t_sou->sou_first_member != NULL && 3521 types_compatible(struct_tp->t_sou->sou_first_member->s_type, 3522 member_tp, true, false, NULL); 3523 } 3524 3525 static bool 3526 is_byte_array(const type_t *tp) 3527 { 3528 3529 return tp->t_tspec == ARRAY && 3530 (tp->t_subt->t_tspec == CHAR || tp->t_subt->t_tspec == UCHAR); 3531 } 3532 3533 static bool 3534 union_contains(const type_t *utp, const type_t *mtp) 3535 { 3536 for (const sym_t *mem = utp->t_sou->sou_first_member; 3537 mem != NULL; mem = mem->s_next) { 3538 if (types_compatible(mem->s_type, mtp, true, false, NULL)) 3539 return true; 3540 } 3541 return false; 3542 } 3543 3544 static bool 3545 should_warn_about_pointer_cast(const type_t *nstp, tspec_t nst, 3546 const type_t *ostp, tspec_t ost) 3547 { 3548 3549 while (nst == ARRAY) 3550 nstp = nstp->t_subt, nst = nstp->t_tspec; 3551 while (ost == ARRAY) 3552 ostp = ostp->t_subt, ost = ostp->t_tspec; 3553 3554 if (nst == STRUCT && ost == STRUCT && 3555 (struct_starts_with(nstp, ostp) || 3556 struct_starts_with(ostp, nstp))) 3557 return false; 3558 3559 if (is_incomplete(nstp) || is_incomplete(ostp)) 3560 return false; 3561 3562 if (nst == CHAR || nst == UCHAR) 3563 return false; /* for the sake of traditional C code */ 3564 if (ost == CHAR || ost == UCHAR) 3565 return false; /* for the sake of traditional C code */ 3566 3567 /* Allow cast between pointers to sockaddr variants. */ 3568 if (nst == STRUCT && ost == STRUCT) { 3569 const sym_t *nmem = nstp->t_sou->sou_first_member; 3570 const sym_t *omem = ostp->t_sou->sou_first_member; 3571 while (nmem != NULL && omem != NULL && 3572 types_compatible(nmem->s_type, omem->s_type, 3573 true, false, NULL)) 3574 nmem = nmem->s_next, omem = omem->s_next; 3575 if (nmem != NULL && is_byte_array(nmem->s_type)) 3576 return false; 3577 if (omem != NULL && is_byte_array(omem->s_type)) 3578 return false; 3579 if (nmem == NULL && omem == NULL) 3580 return false; 3581 } 3582 3583 if (nst == UNION || ost == UNION) { 3584 const type_t *union_tp = nst == UNION ? nstp : ostp; 3585 const type_t *other_tp = nst == UNION ? ostp : nstp; 3586 if (union_contains(union_tp, other_tp)) 3587 return false; 3588 } 3589 3590 if (is_struct_or_union(nst) && is_struct_or_union(ost)) 3591 return nstp->t_sou != ostp->t_sou; 3592 3593 enum rank_kind rk1 = type_properties(nst)->tt_rank_kind; 3594 enum rank_kind rk2 = type_properties(ost)->tt_rank_kind; 3595 if (rk1 != rk2 || rk1 == RK_NONE) 3596 return true; 3597 3598 return portable_rank_cmp(nst, ost) != 0; 3599 } 3600 3601 static void 3602 convert_pointer_from_pointer(type_t *ntp, tnode_t *tn) 3603 { 3604 const type_t *nstp = ntp->t_subt; 3605 const type_t *otp = tn->tn_type; 3606 const type_t *ostp = otp->t_subt; 3607 tspec_t nst = nstp->t_tspec; 3608 tspec_t ost = ostp->t_tspec; 3609 3610 if (nst == VOID || ost == VOID) { 3611 /* TODO: C99 behaves like C90 here. */ 3612 if ((!allow_trad && !allow_c99) && (nst == FUNC || ost == FUNC)) { 3613 const char *nts, *ots; 3614 /* null pointers are already handled in convert() */ 3615 *(nst == FUNC ? &nts : &ots) = "function pointer"; 3616 *(nst == VOID ? &nts : &ots) = "'void *'"; 3617 /* conversion of %s to %s requires a cast */ 3618 warning(303, ots, nts); 3619 } 3620 return; 3621 } 3622 if (nst == FUNC && ost == FUNC) 3623 return; 3624 if (nst == FUNC || ost == FUNC) { 3625 /* converting '%s' to '%s' is questionable */ 3626 warning(229, type_name(otp), type_name(ntp)); 3627 return; 3628 } 3629 3630 if (hflag && alignment_in_bits(nstp) > alignment_in_bits(ostp) && 3631 ost != CHAR && ost != UCHAR && 3632 !is_incomplete(ostp) && 3633 !(nst == UNION && union_contains(nstp, ostp))) { 3634 /* converting '%s' to '%s' increases alignment ... */ 3635 warning(135, type_name(otp), type_name(ntp), 3636 alignment_in_bits(ostp) / CHAR_SIZE, 3637 alignment_in_bits(nstp) / CHAR_SIZE); 3638 } 3639 3640 if (cflag && should_warn_about_pointer_cast(nstp, nst, ostp, ost)) { 3641 /* pointer cast from '%s' to '%s' may be troublesome */ 3642 warning(247, type_name(otp), type_name(ntp)); 3643 } 3644 } 3645 3646 /* 3647 * Insert a conversion operator, which converts the type of the node 3648 * to another given type. 3649 * 3650 * Possible values for 'op': 3651 * CVT a cast-expression 3652 * binary integer promotion for one of the operands, or a usual 3653 * arithmetic conversion 3654 * binary plain or compound assignments to bit-fields 3655 * FARG 'arg' is the number of the parameter (used for warnings) 3656 * NOOP several other implicit conversions 3657 * ... 3658 */ 3659 tnode_t * 3660 convert(op_t op, int arg, type_t *tp, tnode_t *tn) 3661 { 3662 tspec_t nt = tp->t_tspec; 3663 tspec_t ot = tn->tn_type->t_tspec; 3664 3665 if (allow_trad && allow_c90 && op == FARG) 3666 check_prototype_conversion(arg, nt, ot, tp, tn); 3667 3668 if (nt == BOOL) { 3669 /* No further checks. */ 3670 3671 } else if (is_integer(nt)) { 3672 if (ot == BOOL) { 3673 /* No further checks. */ 3674 } else if (is_integer(ot)) 3675 convert_integer_from_integer(op, arg, nt, ot, tp, tn); 3676 else if (is_floating(ot)) 3677 convert_integer_from_floating(op, tp, tn); 3678 else if (ot == PTR) 3679 convert_integer_from_pointer(op, nt, tp, tn); 3680 3681 } else if (is_floating(nt)) { 3682 /* No further checks. */ 3683 3684 } else if (nt == PTR) { 3685 if (is_null_pointer(tn)) { 3686 /* a null pointer may be assigned to any pointer. */ 3687 } else if (ot == PTR && op == CVT) 3688 convert_pointer_from_pointer(tp, tn); 3689 } 3690 3691 tnode_t *ntn = expr_alloc_tnode(); 3692 ntn->tn_op = CVT; 3693 ntn->tn_type = tp; 3694 ntn->tn_cast = op == CVT; 3695 ntn->tn_sys |= tn->tn_sys; 3696 ntn->tn_right = NULL; 3697 if (tn->tn_op != CON || nt == VOID) { 3698 ntn->tn_left = tn; 3699 } else { 3700 ntn->tn_op = CON; 3701 convert_constant(op, arg, ntn->tn_type, &ntn->tn_val, 3702 &tn->tn_val); 3703 } 3704 3705 return ntn; 3706 } 3707 3708 static void 3709 convert_constant_floating(op_t op, int arg, tspec_t ot, const type_t *tp, 3710 tspec_t nt, val_t *v, val_t *nv) 3711 { 3712 long double max = 0.0, min = 0.0; 3713 3714 switch (nt) { 3715 case CHAR: 3716 max = TARG_CHAR_MAX; min = TARG_CHAR_MIN; break; 3717 case UCHAR: 3718 max = TARG_UCHAR_MAX; min = 0; break; 3719 case SCHAR: 3720 max = TARG_SCHAR_MAX; min = TARG_SCHAR_MIN; break; 3721 case SHORT: 3722 max = TARG_SHRT_MAX; min = TARG_SHRT_MIN; break; 3723 case USHORT: 3724 max = TARG_USHRT_MAX; min = 0; break; 3725 case ENUM: 3726 case INT: 3727 max = TARG_INT_MAX; min = TARG_INT_MIN; break; 3728 case UINT: 3729 max = TARG_UINT_MAX; min = 0; break; 3730 case LONG: 3731 max = TARG_LONG_MAX; min = TARG_LONG_MIN; break; 3732 case ULONG: 3733 max = TARG_ULONG_MAX; min = 0; break; 3734 case LLONG: 3735 max = LLONG_MAX; min = LLONG_MIN; break; 3736 case ULLONG: 3737 max = ULLONG_MAX; min = 0; break; 3738 case FLOAT: 3739 case FCOMPLEX: 3740 max = FLT_MAX; min = -FLT_MAX; break; 3741 case DOUBLE: 3742 case DCOMPLEX: 3743 max = DBL_MAX; min = -DBL_MAX; break; 3744 case PTR: 3745 /* Already got an error because of float --> ptr */ 3746 case LDOUBLE: 3747 case LCOMPLEX: 3748 /* LINTED 248 */ 3749 max = LDBL_MAX; min = -max; break; 3750 default: 3751 lint_assert(/*CONSTCOND*/false); 3752 } 3753 if (v->u.floating > max || v->u.floating < min) { 3754 lint_assert(nt != LDOUBLE); 3755 if (op == FARG) { 3756 /* conversion of '%s' to '%s' is out of range, ... */ 3757 warning(295, 3758 type_name(gettyp(ot)), type_name(tp), arg); 3759 } else { 3760 /* conversion of '%s' to '%s' is out of range */ 3761 warning(119, type_name(gettyp(ot)), type_name(tp)); 3762 } 3763 v->u.floating = v->u.floating > 0 ? max : min; 3764 } 3765 3766 if (nt == FLOAT || nt == FCOMPLEX) 3767 nv->u.floating = (float)v->u.floating; 3768 else if (nt == DOUBLE || nt == DCOMPLEX) 3769 nv->u.floating = (double)v->u.floating; 3770 else if (nt == LDOUBLE || nt == LCOMPLEX) 3771 nv->u.floating = v->u.floating; 3772 else 3773 nv->u.integer = (int64_t)v->u.floating; 3774 } 3775 3776 static bool 3777 convert_constant_to_floating(tspec_t nt, val_t *nv, 3778 tspec_t ot, const val_t *v) 3779 { 3780 if (nt == FLOAT) { 3781 nv->u.floating = (ot == PTR || is_uinteger(ot)) ? 3782 (float)(uint64_t)v->u.integer : (float)v->u.integer; 3783 } else if (nt == DOUBLE) { 3784 nv->u.floating = (ot == PTR || is_uinteger(ot)) ? 3785 (double)(uint64_t)v->u.integer : (double)v->u.integer; 3786 } else if (nt == LDOUBLE) { 3787 nv->u.floating = (ot == PTR || is_uinteger(ot)) 3788 ? (long double)(uint64_t)v->u.integer 3789 : (long double)v->u.integer; 3790 } else 3791 return false; 3792 return true; 3793 } 3794 3795 /* 3796 * Print a warning if bits which were set are lost due to the conversion. 3797 * This can happen with operator ORASS only. 3798 */ 3799 static void 3800 convert_constant_check_range_bitor(size_t nsz, size_t osz, const val_t *v, 3801 uint64_t xmask, op_t op) 3802 { 3803 if (nsz < osz && (v->u.integer & xmask) != 0) { 3804 /* constant truncated by conversion, op '%s' */ 3805 warning(306, op_name(op)); 3806 } 3807 } 3808 3809 /* 3810 * Print a warning if additional bits are not all 1 3811 * and the most significant bit of the old value is 1, 3812 * or if at least one (but not all) removed bit was 0. 3813 */ 3814 static void 3815 convert_constant_check_range_bitand(size_t nsz, size_t osz, 3816 uint64_t xmask, const val_t *nv, 3817 tspec_t ot, const val_t *v, 3818 const type_t *tp, op_t op) 3819 { 3820 if (nsz > osz && 3821 (nv->u.integer & bit((unsigned int)(osz - 1))) != 0 && 3822 (nv->u.integer & xmask) != xmask) { 3823 /* extra bits set to 0 in conversion of '%s' to '%s', ... */ 3824 warning(309, type_name(gettyp(ot)), 3825 type_name(tp), op_name(op)); 3826 } else if (nsz < osz && 3827 (v->u.integer & xmask) != xmask && 3828 (v->u.integer & xmask) != 0) { 3829 /* constant truncated by conversion, op '%s' */ 3830 warning(306, op_name(op)); 3831 } 3832 } 3833 3834 static void 3835 convert_constant_check_range_signed(op_t op, int arg) 3836 { 3837 if (op == ASSIGN) { 3838 /* assignment of negative constant to unsigned type */ 3839 warning(164); 3840 } else if (op == INIT) { 3841 /* initialization of unsigned with negative constant */ 3842 warning(221); 3843 } else if (op == FARG) { 3844 /* conversion of negative constant to unsigned type, ... */ 3845 warning(296, arg); 3846 } else if (modtab[op].m_comparison) { 3847 /* handled by check_integer_comparison() */ 3848 } else { 3849 /* conversion of negative constant to unsigned type */ 3850 warning(222); 3851 } 3852 } 3853 3854 /* 3855 * Loss of significant bit(s). All truncated bits of unsigned types or all 3856 * truncated bits plus the msb of the target for signed types are considered 3857 * to be significant bits. Loss of significant bits means that at least one 3858 * of the bits was set in an unsigned type or that at least one but not all 3859 * of the bits was set in a signed type. Loss of significant bits means that 3860 * it is not possible, also not with necessary casts, to convert back to the 3861 * original type. An example for a necessary cast is: 3862 * char c; int i; c = 128; 3863 * i = c; ** yields -128 ** 3864 * i = (unsigned char)c; ** yields 128 ** 3865 */ 3866 static void 3867 warn_constant_check_range_truncated(op_t op, int arg, const type_t *tp, 3868 tspec_t ot) 3869 { 3870 if (op == ASSIGN && tp->t_bitfield) 3871 /* precision lost in bit-field assignment */ 3872 warning(166); 3873 else if (op == ASSIGN) 3874 /* constant truncated by assignment */ 3875 warning(165); 3876 else if (op == INIT && tp->t_bitfield) 3877 /* bit-field initializer does not fit */ 3878 warning(180); 3879 else if (op == INIT) 3880 /* initializer does not fit */ 3881 warning(178); 3882 else if (op == CASE) 3883 /* case label affected by conversion */ 3884 warning(196); 3885 else if (op == FARG) 3886 /* conversion of '%s' to '%s' is out of range, arg #%d */ 3887 warning(295, type_name(gettyp(ot)), type_name(tp), arg); 3888 else 3889 /* conversion of '%s' to '%s' is out of range */ 3890 warning(119, type_name(gettyp(ot)), type_name(tp)); 3891 } 3892 3893 static void 3894 warn_constant_check_range_loss(op_t op, int arg, const type_t *tp, 3895 tspec_t ot) 3896 { 3897 if (op == ASSIGN && tp->t_bitfield) 3898 /* precision lost in bit-field assignment */ 3899 warning(166); 3900 else if (op == INIT && tp->t_bitfield) 3901 /* bit-field initializer out of range */ 3902 warning(11); 3903 else if (op == CASE) 3904 /* case label affected by conversion */ 3905 warning(196); 3906 else if (op == FARG) 3907 /* conversion of '%s' to '%s' is out of range, arg #%d */ 3908 warning(295, type_name(gettyp(ot)), type_name(tp), arg); 3909 else 3910 /* conversion of '%s' to '%s' is out of range */ 3911 warning(119, type_name(gettyp(ot)), type_name(tp)); 3912 } 3913 3914 static void 3915 convert_constant_check_range(tspec_t ot, const type_t *tp, tspec_t nt, 3916 op_t op, int arg, const val_t *v, val_t *nv) 3917 { 3918 unsigned int obitsz, nbitsz; 3919 uint64_t xmask, xmsk1; 3920 3921 obitsz = size_in_bits(ot); 3922 nbitsz = tp->t_bitfield ? tp->t_bit_field_width : size_in_bits(nt); 3923 xmask = value_bits(nbitsz) ^ value_bits(obitsz); 3924 xmsk1 = value_bits(nbitsz) ^ value_bits(obitsz - 1); 3925 /* 3926 * For bitwise operations we are not interested in the arithmetic 3927 * value, but in the bits itself. 3928 */ 3929 if (op == ORASS || op == BITOR || op == BITXOR) { 3930 convert_constant_check_range_bitor( 3931 nbitsz, obitsz, v, xmask, op); 3932 } else if (op == ANDASS || op == BITAND) { 3933 convert_constant_check_range_bitand( 3934 nbitsz, obitsz, xmask, nv, ot, v, tp, op); 3935 } else if ((nt != PTR && is_uinteger(nt)) && 3936 (ot != PTR && !is_uinteger(ot)) && 3937 v->u.integer < 0) 3938 convert_constant_check_range_signed(op, arg); 3939 else if (nv->u.integer != v->u.integer && nbitsz <= obitsz && 3940 (v->u.integer & xmask) != 0 && 3941 (is_uinteger(ot) || (v->u.integer & xmsk1) != xmsk1)) 3942 warn_constant_check_range_truncated(op, arg, tp, ot); 3943 else if (nv->u.integer != v->u.integer) 3944 warn_constant_check_range_loss(op, arg, tp, ot); 3945 } 3946 3947 /*- 3948 * Converts a typed constant to a constant of another type. 3949 * 3950 * op operator which requires conversion 3951 * arg if op is FARG, # of parameter 3952 * tp type to which to convert the constant 3953 * nv new constant 3954 * v old constant 3955 */ 3956 void 3957 convert_constant(op_t op, int arg, const type_t *tp, val_t *nv, val_t *v) 3958 { 3959 /* 3960 * TODO: make 'v' const; the name of this function does not suggest 3961 * that it modifies 'v'. 3962 */ 3963 tspec_t ot = v->v_tspec; 3964 tspec_t nt = nv->v_tspec = tp->t_tspec; 3965 bool range_check = false; 3966 3967 if (nt == BOOL) { /* C99 6.3.1.2 */ 3968 nv->v_unsigned_since_c90 = false; 3969 nv->u.integer = is_nonzero_val(v) ? 1 : 0; 3970 return; 3971 } 3972 3973 if (ot == FLOAT || ot == DOUBLE || ot == LDOUBLE) 3974 convert_constant_floating(op, arg, ot, tp, nt, v, nv); 3975 else if (!convert_constant_to_floating(nt, nv, ot, v)) { 3976 range_check = true; /* Check for lost precision. */ 3977 nv->u.integer = v->u.integer; 3978 } 3979 3980 if (allow_trad && allow_c90 && v->v_unsigned_since_c90 && 3981 (is_floating(nt) || ( 3982 (is_integer(nt) && !is_uinteger(nt) && 3983 portable_rank_cmp(nt, ot) > 0)))) { 3984 /* C90 treats constant as unsigned */ 3985 warning(157); 3986 v->v_unsigned_since_c90 = false; 3987 } 3988 3989 if (is_integer(nt)) { 3990 nv->u.integer = convert_integer(nv->u.integer, nt, 3991 tp->t_bitfield ? tp->t_bit_field_width : size_in_bits(nt)); 3992 } 3993 3994 if (range_check && op != CVT) 3995 convert_constant_check_range(ot, tp, nt, op, arg, v, nv); 3996 } 3997 3998 /* 3999 * Create a constant node for sizeof. 4000 */ 4001 tnode_t * 4002 build_sizeof(const type_t *tp) 4003 { 4004 unsigned int size_in_bytes = type_size_in_bits(tp) / CHAR_SIZE; 4005 tnode_t *tn = build_integer_constant(SIZEOF_TSPEC, size_in_bytes); 4006 tn->tn_system_dependent = true; 4007 debug_step("build_sizeof '%s' = %u", type_name(tp), size_in_bytes); 4008 return tn; 4009 } 4010 4011 /* 4012 * Create a constant node for offsetof. 4013 */ 4014 tnode_t * 4015 build_offsetof(const type_t *tp, const sym_t *sym) 4016 { 4017 unsigned int offset_in_bits = 0; 4018 4019 if (!is_struct_or_union(tp->t_tspec)) { 4020 /* unacceptable operand of '%s' */ 4021 error(111, "offsetof"); 4022 goto proceed; 4023 } 4024 sym_t *mem = find_member(tp->t_sou, sym->s_name); 4025 if (mem == NULL) { 4026 /* type '%s' does not have member '%s' */ 4027 error(101, sym->s_name, type_name(tp)); 4028 goto proceed; 4029 } 4030 offset_in_bits = mem->u.s_member.sm_offset_in_bits; 4031 4032 proceed:; 4033 unsigned int offset_in_bytes = offset_in_bits / CHAR_SIZE; 4034 tnode_t *tn = build_integer_constant(SIZEOF_TSPEC, offset_in_bytes); 4035 tn->tn_system_dependent = true; 4036 return tn; 4037 } 4038 4039 unsigned int 4040 type_size_in_bits(const type_t *tp) 4041 { 4042 4043 unsigned int elem = 1; 4044 bool flex = false; 4045 lint_assert(tp != NULL); 4046 while (tp->t_tspec == ARRAY) { 4047 flex = true; /* allow c99 flex arrays [] [0] */ 4048 elem *= tp->t_dim; 4049 tp = tp->t_subt; 4050 } 4051 if (elem == 0 && !flex) { 4052 /* cannot take size/alignment of incomplete type */ 4053 error(143); 4054 elem = 1; 4055 } 4056 4057 unsigned int elsz; 4058 switch (tp->t_tspec) { 4059 case VOID: 4060 /* cannot take size/alignment of void */ 4061 error(146); 4062 elsz = 1; 4063 break; 4064 case FUNC: 4065 /* cannot take size/alignment of function type '%s' */ 4066 error(144, type_name(tp)); 4067 elsz = 1; 4068 break; 4069 case STRUCT: 4070 case UNION: 4071 if (is_incomplete(tp)) { 4072 /* cannot take size/alignment of incomplete type */ 4073 error(143); 4074 elsz = 1; 4075 } else { 4076 elsz = tp->t_sou->sou_size_in_bits; 4077 } 4078 break; 4079 case ENUM: 4080 if (is_incomplete(tp)) { 4081 /* cannot take size/alignment of incomplete type */ 4082 warning(143); 4083 } 4084 /* FALLTHROUGH */ 4085 default: 4086 if (tp->t_bitfield) { 4087 /* cannot take size/alignment of bit-field */ 4088 error(145); 4089 } 4090 elsz = size_in_bits(tp->t_tspec); 4091 lint_assert(elsz > 0); 4092 break; 4093 } 4094 4095 return elem * elsz; 4096 } 4097 4098 /* C11 6.5.3.4, GCC */ 4099 tnode_t * 4100 build_alignof(const type_t *tp) 4101 { 4102 if (tp->t_tspec == FUNC) { 4103 /* cannot take size/alignment of function type '%s' */ 4104 error(144, type_name(tp)); 4105 return NULL; 4106 } 4107 if (tp->t_tspec == VOID) { 4108 /* cannot take size/alignment of void */ 4109 error(146); 4110 return NULL; 4111 } 4112 if (is_incomplete(tp)) { 4113 /* cannot take size/alignment of incomplete type */ 4114 error(143); 4115 return NULL; 4116 } 4117 if (tp->t_bitfield) { 4118 /* cannot take size/alignment of bit-field */ 4119 error(145); 4120 return NULL; 4121 } 4122 return build_integer_constant(SIZEOF_TSPEC, 4123 (int64_t)alignment_in_bits(tp) / CHAR_SIZE); 4124 } 4125 4126 static tnode_t * 4127 cast_to_union(tnode_t *otn, type_t *ntp) 4128 { 4129 4130 if (!allow_gcc) { 4131 /* union cast is a GCC extension */ 4132 error(328); 4133 return NULL; 4134 } 4135 4136 for (const sym_t *m = ntp->t_sou->sou_first_member; 4137 m != NULL; m = m->s_next) { 4138 if (types_compatible(m->s_type, otn->tn_type, 4139 false, false, NULL)) { 4140 tnode_t *ntn = expr_alloc_tnode(); 4141 ntn->tn_op = CVT; 4142 ntn->tn_type = ntp; 4143 ntn->tn_cast = true; 4144 ntn->tn_left = otn; 4145 ntn->tn_right = NULL; 4146 return ntn; 4147 } 4148 } 4149 4150 /* type '%s' is not a member of '%s' */ 4151 error(329, type_name(otn->tn_type), type_name(ntp)); 4152 return NULL; 4153 } 4154 4155 /* 4156 * Type casts. 4157 */ 4158 tnode_t * 4159 cast(tnode_t *tn, type_t *tp) 4160 { 4161 4162 if (tn == NULL) 4163 return NULL; 4164 4165 tn = cconv(tn); 4166 4167 lint_assert(tp != NULL); 4168 tspec_t nt = tp->t_tspec; 4169 tspec_t ot = tn->tn_type->t_tspec; 4170 4171 if (nt == VOID) { 4172 /* 4173 * C90 6.3.4, C99 6.5.4p2 and C11 6.5.4p2 allow any type to 4174 * be cast to void. The only other allowed casts are from a 4175 * scalar type to a scalar type. 4176 */ 4177 } else if (nt == UNION) 4178 return cast_to_union(tn, tp); 4179 else if (nt == STRUCT || nt == ARRAY || nt == FUNC) { 4180 /* Casting to a struct is an undocumented GCC extension. */ 4181 if (!(allow_gcc && nt == STRUCT)) 4182 goto invalid_cast; 4183 } else if (is_struct_or_union(ot)) 4184 goto invalid_cast; 4185 else if (ot == VOID) { 4186 /* improper cast of void expression */ 4187 error(148); 4188 return NULL; 4189 } else if (is_integer(nt) && is_scalar(ot)) { 4190 /* ok */ 4191 } else if (is_floating(nt) && is_arithmetic(ot)) { 4192 /* ok */ 4193 } else if (nt == PTR && is_integer(ot)) { 4194 /* ok */ 4195 } else if (nt == PTR && ot == PTR) { 4196 if (!tp->t_subt->t_const && tn->tn_type->t_subt->t_const) { 4197 if (hflag) 4198 /* cast discards 'const' from type '%s' */ 4199 warning(275, type_name(tn->tn_type)); 4200 } 4201 } else 4202 goto invalid_cast; 4203 4204 if (any_query_enabled && types_compatible(tp, tn->tn_type, 4205 false, false, NULL)) { 4206 /* no-op cast from '%s' to '%s' */ 4207 query_message(6, type_name(tn->tn_type), type_name(tp)); 4208 } 4209 4210 tn = convert(CVT, 0, tp, tn); 4211 tn->tn_cast = true; 4212 4213 return tn; 4214 4215 invalid_cast: 4216 /* invalid cast from '%s' to '%s' */ 4217 error(147, type_name(tn->tn_type), type_name(tp)); 4218 return NULL; 4219 } 4220 4221 /* 4222 * Create the node for a function argument. 4223 * All necessary conversions and type checks are done in 4224 * build_function_call because build_function_argument has no 4225 * information about the expected parameter types. 4226 */ 4227 tnode_t * 4228 build_function_argument(tnode_t *args, tnode_t *arg) 4229 { 4230 /* 4231 * If there was a serious error in the expression for the argument, 4232 * create a dummy argument so the positions of the remaining arguments 4233 * will not change. 4234 */ 4235 if (arg == NULL) 4236 arg = build_integer_constant(INT, 0); 4237 4238 return build_op(PUSH, arg->tn_sys, arg->tn_type, arg, args); 4239 } 4240 4241 /* 4242 * Compare the type of an argument with the corresponding type of a 4243 * prototype parameter. If it is a valid combination, but both types 4244 * are not the same, insert a conversion to convert the argument into 4245 * the type of the parameter. 4246 */ 4247 static tnode_t * 4248 check_prototype_argument( 4249 int n, /* pos of arg */ 4250 type_t *tp, /* expected type (from prototype) */ 4251 tnode_t *tn) /* argument */ 4252 { 4253 tnode_t *ln = xcalloc(1, sizeof(*ln)); 4254 ln->tn_type = expr_unqualified_type(tp); 4255 ln->tn_lvalue = true; 4256 if (typeok(FARG, n, ln, tn)) { 4257 bool dowarn; 4258 if (!types_compatible(tp, tn->tn_type, 4259 true, false, (dowarn = false, &dowarn)) || dowarn) 4260 tn = convert(FARG, n, tp, tn); 4261 } 4262 free(ln); 4263 return tn; 4264 } 4265 4266 /* 4267 * Check types of all function arguments and insert conversions, 4268 * if necessary. 4269 */ 4270 static tnode_t * 4271 check_function_arguments(type_t *ftp, tnode_t *args) 4272 { 4273 /* get # of parameters in the prototype */ 4274 int npar = 0; 4275 for (const sym_t *p = ftp->t_params; p != NULL; p = p->s_next) 4276 npar++; 4277 4278 /* get # of arguments in the function call */ 4279 int narg = 0; 4280 for (const tnode_t *arg = args; arg != NULL; arg = tn_ck_right(arg)) 4281 narg++; 4282 4283 const sym_t *param = ftp->t_params; 4284 if (ftp->t_proto && npar != narg && !(ftp->t_vararg && npar < narg)) { 4285 /* argument mismatch: %d %s passed, %d expected */ 4286 error(150, narg, narg != 1 ? "arguments" : "argument", npar); 4287 param = NULL; 4288 } 4289 4290 for (int n = 1; n <= narg; n++) { 4291 4292 // The rightmost argument starts the argument list. 4293 tnode_t *arg = args; 4294 for (int i = narg; i > n; i--, arg = arg->tn_right) 4295 continue; 4296 4297 /* some things which are always not allowed */ 4298 tspec_t at = arg->tn_left->tn_type->t_tspec; 4299 if (at == VOID) { 4300 /* void expressions may not be arguments, arg #%d */ 4301 error(151, n); 4302 return NULL; 4303 } 4304 if (is_struct_or_union(at) && 4305 is_incomplete(arg->tn_left->tn_type)) { 4306 /* argument cannot have unknown size, arg #%d */ 4307 error(152, n); 4308 return NULL; 4309 } 4310 if (is_integer(at) && 4311 arg->tn_left->tn_type->t_is_enum && 4312 is_incomplete(arg->tn_left->tn_type)) { 4313 /* argument cannot have unknown size, arg #%d */ 4314 warning(152, n); 4315 } 4316 4317 /* class conversions (arg in value context) */ 4318 arg->tn_left = cconv(arg->tn_left); 4319 4320 if (param != NULL) { 4321 arg->tn_left = check_prototype_argument( 4322 n, param->s_type, arg->tn_left); 4323 } else 4324 arg->tn_left = promote(NOOP, true, arg->tn_left); 4325 arg->tn_type = arg->tn_left->tn_type; 4326 4327 if (param != NULL) 4328 param = param->s_next; 4329 } 4330 4331 return args; 4332 } 4333 4334 /* 4335 * Create the node for a function call. Also check types of 4336 * function arguments and insert conversions, if necessary. 4337 */ 4338 tnode_t * 4339 build_function_call(tnode_t *func, bool sys, tnode_t *args) 4340 { 4341 4342 if (func == NULL) 4343 return NULL; 4344 4345 op_t fcop = func->tn_op == NAME && func->tn_type->t_tspec == FUNC 4346 ? CALL : ICALL; 4347 4348 check_ctype_function_call(func, args); 4349 4350 /* Turn the function name into a pointer to the function. */ 4351 func = cconv(func); 4352 4353 if (func->tn_type->t_tspec != PTR || 4354 func->tn_type->t_subt->t_tspec != FUNC) { 4355 /* cannot call '%s', must be a function */ 4356 error(149, type_name(func->tn_type)); 4357 return NULL; 4358 } 4359 4360 args = check_function_arguments(func->tn_type->t_subt, args); 4361 4362 return build_op(fcop, sys, func->tn_type->t_subt->t_subt, func, args); 4363 } 4364 4365 /* 4366 * Return the value of an integral constant expression. 4367 * If the expression is not constant or its type is not an integer 4368 * type, an error message is printed. 4369 */ 4370 val_t * 4371 integer_constant(tnode_t *tn, bool required) 4372 { 4373 4374 if (tn != NULL) 4375 tn = cconv(tn); 4376 if (tn != NULL) 4377 tn = promote(NOOP, false, tn); 4378 4379 val_t *v = xcalloc(1, sizeof(*v)); 4380 4381 if (tn == NULL) { 4382 lint_assert(seen_error); 4383 debug_step("constant node is null; returning 1 instead"); 4384 v->v_tspec = INT; 4385 v->u.integer = 1; 4386 return v; 4387 } 4388 4389 v->v_tspec = tn->tn_type->t_tspec; 4390 4391 if (tn->tn_op == CON) { 4392 lint_assert(tn->tn_type->t_tspec == tn->tn_val.v_tspec); 4393 if (is_integer(tn->tn_val.v_tspec)) { 4394 v->v_unsigned_since_c90 = 4395 tn->tn_val.v_unsigned_since_c90; 4396 v->u.integer = tn->tn_val.u.integer; 4397 return v; 4398 } 4399 v->u.integer = (int64_t)tn->tn_val.u.floating; 4400 } else { 4401 v->u.integer = 1; 4402 } 4403 4404 if (required) 4405 /* integral constant expression expected */ 4406 error(55); 4407 else 4408 /* variable array dimension is a C99/GCC extension */ 4409 c99ism(318); 4410 4411 if (!is_integer(v->v_tspec)) 4412 v->v_tspec = INT; 4413 4414 return v; 4415 } 4416 4417 static bool 4418 is_constcond_false(const tnode_t *tn, tspec_t t) 4419 { 4420 return (t == BOOL || t == INT) && 4421 tn->tn_op == CON && tn->tn_val.u.integer == 0; 4422 } 4423 4424 /* 4425 * Perform some tests on expressions which can't be done in build_binary() 4426 * and functions called by build_binary(). These tests must be done here 4427 * because we need some information about the context in which the operations 4428 * are performed. 4429 * After all tests are performed and dofreeblk is true, expr() frees the 4430 * memory which is used for the expression. 4431 */ 4432 void 4433 expr(tnode_t *tn, bool vctx, bool cond, bool dofreeblk, bool is_do_while) 4434 { 4435 4436 if (tn == NULL) { /* in case of errors */ 4437 expr_free_all(); 4438 return; 4439 } 4440 4441 /* expr() is also called in global initializations */ 4442 if (dcs->d_kind != DLK_EXTERN && !is_do_while) 4443 check_statement_reachable(); 4444 4445 check_expr_misc(tn, vctx, cond, !cond, false, false, false); 4446 if (tn->tn_op == ASSIGN && !tn->tn_parenthesized) { 4447 if (hflag && cond) 4448 /* assignment in conditional context */ 4449 warning(159); 4450 } else if (tn->tn_op == CON) { 4451 if (hflag && cond && !suppress_constcond && 4452 !tn->tn_system_dependent && 4453 !(is_do_while && 4454 is_constcond_false(tn, tn->tn_type->t_tspec))) 4455 /* constant in conditional context */ 4456 warning(161); 4457 } 4458 if (!modtab[tn->tn_op].m_has_side_effect) { 4459 /* 4460 * for left operands of COMMA this warning is already 4461 * printed 4462 */ 4463 if (tn->tn_op != COMMA && !vctx && !cond) 4464 check_null_effect(tn); 4465 } 4466 debug_node(tn); 4467 4468 /* free the tree memory */ 4469 if (dofreeblk) 4470 expr_free_all(); 4471 } 4472 4473 /* 4474 * Checks the range of array indices, if possible. 4475 * amper is set if only the address of the element is used. This 4476 * means that the index is allowed to refer to the first element 4477 * after the array. 4478 */ 4479 static void 4480 check_array_index(tnode_t *tn, bool amper) 4481 { 4482 lint_assert(has_operands(tn)); 4483 const tnode_t *ln = tn->tn_left; 4484 const tnode_t *rn = tn->tn_right; 4485 4486 /* We can only check constant indices. */ 4487 if (rn->tn_op != CON) 4488 return; 4489 4490 /* Return if the left node does not stem from an array. */ 4491 if (ln->tn_op != ADDR) 4492 return; 4493 if (ln->tn_left->tn_op != STRING && ln->tn_left->tn_op != NAME) 4494 return; 4495 if (ln->tn_left->tn_type->t_tspec != ARRAY) 4496 return; 4497 4498 /* 4499 * For incomplete array types, we can print a warning only if 4500 * the index is negative. 4501 */ 4502 if (is_incomplete(ln->tn_left->tn_type) && rn->tn_val.u.integer >= 0) 4503 return; 4504 4505 /* Get the size of one array element */ 4506 int elsz = length_in_bits(ln->tn_type->t_subt, NULL); 4507 if (elsz == 0) 4508 return; 4509 elsz /= CHAR_SIZE; 4510 4511 /* Change the unit of the index from bytes to element size. */ 4512 int64_t con = is_uinteger(rn->tn_type->t_tspec) 4513 ? (int64_t)((uint64_t)rn->tn_val.u.integer / elsz) 4514 : rn->tn_val.u.integer / elsz; 4515 4516 int dim = ln->tn_left->tn_type->t_dim + (amper ? 1 : 0); 4517 4518 if (!is_uinteger(rn->tn_type->t_tspec) && con < 0) { 4519 /* array subscript cannot be negative: %ld */ 4520 warning(167, (long)con); 4521 } else if (dim > 0 && (uint64_t)con >= (uint64_t)dim) { 4522 /* array subscript cannot be > %d: %ld */ 4523 warning(168, dim - 1, (long)con); 4524 } 4525 } 4526 4527 static void 4528 check_expr_addr(const tnode_t *ln, bool szof, bool fcall) 4529 { 4530 /* XXX: Taking warn_about_unreachable into account here feels wrong. */ 4531 if (ln->tn_op == NAME && (reached || !warn_about_unreachable)) { 4532 if (!szof) 4533 mark_as_set(ln->tn_sym); 4534 mark_as_used(ln->tn_sym, fcall, szof); 4535 } 4536 if (ln->tn_op == INDIR && ln->tn_left->tn_op == PLUS) 4537 /* check the range of array indices */ 4538 check_array_index(ln->tn_left, true); 4539 } 4540 4541 static void 4542 check_expr_load(const tnode_t *ln) 4543 { 4544 if (ln->tn_op == INDIR && ln->tn_left->tn_op == PLUS) 4545 /* check the range of array indices */ 4546 check_array_index(ln->tn_left, false); 4547 } 4548 4549 /* 4550 * If there is an asm statement in one of the compound statements around, 4551 * there may be other side effects, so don't warn. 4552 */ 4553 static bool 4554 is_asm_around(void) 4555 { 4556 for (decl_level *dl = dcs; dl != NULL; dl = dl->d_enclosing) 4557 if (dl->d_asm) 4558 return true; 4559 return false; 4560 } 4561 4562 static void 4563 check_expr_side_effect(const tnode_t *ln, bool szof) 4564 { 4565 4566 /* XXX: Taking warn_about_unreachable into account here feels wrong. */ 4567 if (ln->tn_op == NAME && (reached || !warn_about_unreachable)) { 4568 scl_t sc = ln->tn_sym->s_scl; 4569 if (sc != EXTERN && sc != STATIC && 4570 !ln->tn_sym->s_set && !szof && !is_asm_around()) { 4571 /* '%s' may be used before set */ 4572 warning(158, ln->tn_sym->s_name); 4573 mark_as_set(ln->tn_sym); 4574 } 4575 mark_as_used(ln->tn_sym, false, false); 4576 } 4577 } 4578 4579 static void 4580 check_expr_assign(const tnode_t *ln, bool szof) 4581 { 4582 /* XXX: Taking warn_about_unreachable into account here feels wrong. */ 4583 if (ln->tn_op == NAME && !szof && (reached || !warn_about_unreachable)) { 4584 mark_as_set(ln->tn_sym); 4585 if (ln->tn_sym->s_scl == EXTERN) 4586 outusg(ln->tn_sym); 4587 } 4588 if (ln->tn_op == INDIR && ln->tn_left->tn_op == PLUS) 4589 /* check the range of array indices */ 4590 check_array_index(ln->tn_left, false); 4591 } 4592 4593 static void 4594 check_expr_call(const tnode_t *tn, const tnode_t *ln, 4595 bool szof, bool vctx, bool cond, bool retval_discarded) 4596 { 4597 lint_assert(ln->tn_op == ADDR); 4598 lint_assert(ln->tn_left->tn_op == NAME); 4599 if (!szof && !is_compiler_builtin(ln->tn_left->tn_sym->s_name)) 4600 outcall(tn, vctx || cond, retval_discarded); 4601 } 4602 4603 static void 4604 check_expr_op(const tnode_t *tn, op_t op, const tnode_t *ln, 4605 bool szof, bool fcall, bool vctx, bool cond, 4606 bool retval_discarded, bool eqwarn) 4607 { 4608 switch (op) { 4609 case ADDR: 4610 check_expr_addr(ln, szof, fcall); 4611 break; 4612 case LOAD: 4613 check_expr_load(ln); 4614 /* FALLTHROUGH */ 4615 case PUSH: 4616 case INCBEF: 4617 case DECBEF: 4618 case INCAFT: 4619 case DECAFT: 4620 case ADDASS: 4621 case SUBASS: 4622 case MULASS: 4623 case DIVASS: 4624 case MODASS: 4625 case ANDASS: 4626 case ORASS: 4627 case XORASS: 4628 case SHLASS: 4629 case SHRASS: 4630 case REAL: 4631 case IMAG: 4632 check_expr_side_effect(ln, szof); 4633 break; 4634 case ASSIGN: 4635 check_expr_assign(ln, szof); 4636 break; 4637 case CALL: 4638 check_expr_call(tn, ln, szof, vctx, cond, retval_discarded); 4639 break; 4640 case EQ: 4641 if (hflag && eqwarn) 4642 /* operator '==' found where '=' was expected */ 4643 warning(160); 4644 break; 4645 default: 4646 break; 4647 } 4648 } 4649 4650 /* 4651 * vctx ??? 4652 * cond whether the expression is a condition that 4653 * will be compared with 0 4654 * eqwarn whether the operator '==' might be a 4655 * misspelled '=' 4656 * fcall whether the expression is a function call 4657 * retval_discarded whether the return value of a function call 4658 * is discarded; such calls will be analyzed by 4659 * lint2 in messages 4, 8 and 9 4660 * szof whether the expression is part of a sizeof 4661 * expression, which means that its value is 4662 * discarded since only the type is relevant 4663 */ 4664 void 4665 check_expr_misc(const tnode_t *tn, bool vctx, bool cond, 4666 bool eqwarn, bool fcall, bool retval_discarded, bool szof) 4667 { 4668 4669 if (tn == NULL) 4670 return; 4671 op_t op = tn->tn_op; 4672 if (op == NAME || op == CON || op == STRING) 4673 return; 4674 4675 lint_assert(has_operands(tn)); 4676 tnode_t *ln = tn->tn_left; 4677 tnode_t *rn = tn->tn_right; 4678 check_expr_op(tn, op, ln, 4679 szof, fcall, vctx, cond, retval_discarded, eqwarn); 4680 4681 const mod_t *mp = &modtab[op]; 4682 bool cvctx = mp->m_value_context; 4683 bool ccond = mp->m_compares_with_zero; 4684 bool eq = mp->m_warn_if_operand_eq && 4685 !ln->tn_parenthesized && 4686 rn != NULL && !rn->tn_parenthesized; 4687 4688 /* 4689 * values of operands of ':' are not used if the type of at least 4690 * one of the operands (for gcc compatibility) is void 4691 * XXX test/value context of QUEST should probably be used as 4692 * context for both operands of COLON 4693 */ 4694 if (op == COLON && tn->tn_type->t_tspec == VOID) 4695 cvctx = ccond = false; 4696 bool discard = op == CVT && tn->tn_type->t_tspec == VOID; 4697 check_expr_misc(ln, cvctx, ccond, eq, op == CALL, discard, szof); 4698 4699 switch (op) { 4700 case PUSH: 4701 if (rn != NULL) 4702 check_expr_misc(rn, false, false, eq, false, false, 4703 szof); 4704 break; 4705 case LOGAND: 4706 case LOGOR: 4707 check_expr_misc(rn, false, true, eq, false, false, szof); 4708 break; 4709 case COLON: 4710 check_expr_misc(rn, cvctx, ccond, eq, false, false, szof); 4711 break; 4712 case COMMA: 4713 check_expr_misc(rn, vctx, cond, false, false, false, szof); 4714 break; 4715 default: 4716 if (mp->m_binary) 4717 check_expr_misc(rn, true, false, eq, false, false, 4718 szof); 4719 break; 4720 } 4721 } 4722 4723 /* 4724 * Return whether the expression can be used for static initialization. 4725 * 4726 * Constant initialization expressions must be constant or an address 4727 * of a static object with an optional offset. In the first case, 4728 * the result is returned in *offsp. In the second case, the static 4729 * object is returned in *symp and the offset in *offsp. 4730 * 4731 * The expression can consist of PLUS, MINUS, ADDR, NAME, STRING and 4732 * CON. Type conversions are allowed if they do not change binary 4733 * representation (including width). 4734 * 4735 * C99 6.6 "Constant expressions" 4736 * C99 6.7.8p4 restricts initializers for static storage duration 4737 */ 4738 bool 4739 constant_addr(const tnode_t *tn, const sym_t **symp, ptrdiff_t *offsp) 4740 { 4741 const sym_t *sym; 4742 ptrdiff_t offs1, offs2; 4743 tspec_t t, ot; 4744 4745 switch (tn->tn_op) { 4746 case MINUS: 4747 if (tn->tn_right->tn_op == CVT) 4748 return constant_addr(tn->tn_right, symp, offsp); 4749 else if (tn->tn_right->tn_op != CON) 4750 return false; 4751 /* FALLTHROUGH */ 4752 case PLUS: 4753 offs1 = offs2 = 0; 4754 if (tn->tn_left->tn_op == CON) { 4755 offs1 = (ptrdiff_t)tn->tn_left->tn_val.u.integer; 4756 if (!constant_addr(tn->tn_right, &sym, &offs2)) 4757 return false; 4758 } else if (tn->tn_right->tn_op == CON) { 4759 offs2 = (ptrdiff_t)tn->tn_right->tn_val.u.integer; 4760 if (tn->tn_op == MINUS) 4761 offs2 = -offs2; 4762 if (!constant_addr(tn->tn_left, &sym, &offs1)) 4763 return false; 4764 } else { 4765 return false; 4766 } 4767 *symp = sym; 4768 *offsp = offs1 + offs2; 4769 return true; 4770 case ADDR: 4771 if (tn->tn_left->tn_op == NAME) { 4772 *symp = tn->tn_left->tn_sym; 4773 *offsp = 0; 4774 return true; 4775 } else { 4776 /* 4777 * If this were the front end of a compiler, we 4778 * would return a label instead of 0, at least if 4779 * 'tn->tn_left->tn_op == STRING'. 4780 */ 4781 *symp = NULL; 4782 *offsp = 0; 4783 return true; 4784 } 4785 case CVT: 4786 t = tn->tn_type->t_tspec; 4787 ot = tn->tn_left->tn_type->t_tspec; 4788 if ((!is_integer(t) && t != PTR) || 4789 (!is_integer(ot) && ot != PTR)) { 4790 return false; 4791 } 4792 #if 0 4793 /* 4794 * consider: 4795 * struct foo { 4796 * unsigned char a; 4797 * } f = { 4798 * (unsigned char)(unsigned long) 4799 * (&(((struct foo *)0)->a)) 4800 * }; 4801 * since psize(unsigned long) != psize(unsigned char), 4802 * this fails. 4803 */ 4804 else if (psize(t) != psize(ot)) 4805 return -1; 4806 #endif 4807 return constant_addr(tn->tn_left, symp, offsp); 4808 default: 4809 return false; 4810 } 4811 } 4812 4813 /* Append s2 to s1, then free s2. */ 4814 strg_t * 4815 cat_strings(strg_t *s1, strg_t *s2) 4816 { 4817 4818 if (s1->st_char != s2->st_char) { 4819 /* cannot concatenate wide and regular string literals */ 4820 error(292); 4821 return s1; 4822 } 4823 4824 size_t len1 = s1->st_len; 4825 size_t len2 = s2->st_len; 4826 size_t chsize = s1->st_char ? sizeof(char) : sizeof(wchar_t); 4827 size_t size1 = len1 * chsize; 4828 size_t size2 = (len2 + 1) * chsize; 4829 s1->st_mem = xrealloc(s1->st_mem, size1 + size2); 4830 memcpy((char *)s1->st_mem + size1, s2->st_mem, size2); 4831 free(s2->st_mem); 4832 4833 s1->st_len = len1 + len2; 4834 free(s2); 4835 4836 return s1; 4837 } 4838 4839 4840 typedef struct stmt_expr { 4841 memory_pool se_mem; 4842 sym_t *se_sym; 4843 struct stmt_expr *se_enclosing; 4844 } stmt_expr; 4845 4846 static stmt_expr *stmt_exprs; 4847 4848 void 4849 begin_statement_expr(void) 4850 { 4851 debug_enter(); 4852 4853 stmt_expr *se = xmalloc(sizeof(*se)); 4854 se->se_mem = expr_save_memory(); 4855 se->se_sym = NULL; 4856 se->se_enclosing = stmt_exprs; 4857 stmt_exprs = se; 4858 } 4859 4860 void 4861 do_statement_expr(tnode_t *tn) 4862 { 4863 block_level--; 4864 mem_block_level--; 4865 stmt_exprs->se_sym = tn != NULL 4866 ? mktempsym(block_dup_type(tn->tn_type)) 4867 : NULL; /* after a syntax error */ 4868 mem_block_level++; 4869 block_level++; 4870 /* '({ ... })' is a GCC extension */ 4871 gnuism(320); 4872 } 4873 4874 tnode_t * 4875 end_statement_expr(void) 4876 { 4877 tnode_t *tn; 4878 4879 stmt_expr *se = stmt_exprs; 4880 if (se->se_sym == NULL) { 4881 tn = NULL; /* after a syntax error */ 4882 goto end; 4883 } 4884 4885 tn = build_name(se->se_sym, false); 4886 (void)expr_save_memory(); /* leak */ 4887 expr_restore_memory(se->se_mem); 4888 stmt_exprs = se->se_enclosing; 4889 free(se); 4890 4891 end: 4892 debug_leave(); 4893 return tn; 4894 } 4895 4896 bool 4897 in_statement_expr(void) 4898 { 4899 return stmt_exprs != NULL; 4900 } 4901
Indexes created Mon Sep 22 21:09:42 GMT 2025