tree.c revision 1.580
1 /* $NetBSD: tree.c,v 1.580 2023/09/12 22:01:05 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 1.580 2023/09/12 22:01:05 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 == NOSCL && !in_gcc_attribute) { 490 sym->s_scl = EXTERN; 491 sym->s_def = DECL; 492 if (is_funcname) 493 build_name_call(sym); 494 else 495 fallback_symbol(sym); 496 } 497 498 lint_assert(sym->s_kind == FVFT || sym->s_kind == FMEMBER); 499 500 tnode_t *n = expr_alloc_tnode(); 501 n->tn_type = sym->s_type; 502 if (sym->s_scl == BOOL_CONST) { 503 n->tn_op = CON; 504 n->tn_val.v_tspec = BOOL; 505 n->tn_val.v_unsigned_since_c90 = false; 506 n->tn_val.v_char_constant = false; 507 n->tn_val.u.integer = sym->u.s_bool_constant ? 1 : 0; 508 } else if (sym->s_scl == ENUM_CONST) { 509 n->tn_op = CON; 510 n->tn_val.v_tspec = INT; /* ENUM is in n->tn_type */ 511 n->tn_val.v_unsigned_since_c90 = false; 512 n->tn_val.v_char_constant = false; 513 n->tn_val.u.integer = sym->u.s_enum_constant; 514 } else { 515 n->tn_op = NAME; 516 n->tn_sym = sym; 517 if (sym->s_kind == FVFT && sym->s_type->t_tspec != FUNC) 518 n->tn_lvalue = true; 519 } 520 521 return n; 522 } 523 524 tnode_t * 525 build_string(strg_t *strg) 526 { 527 size_t len = strg->st_len; 528 529 type_t *tp = expr_zero_alloc(sizeof(*tp), "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 void 580 check_integer_comparison(op_t op, tnode_t *ln, tnode_t *rn) 581 { 582 583 tspec_t lt = ln->tn_type->t_tspec; 584 tspec_t rt = rn->tn_type->t_tspec; 585 586 if (ln->tn_op != CON && rn->tn_op != CON) 587 return; 588 589 if (!is_integer(lt) || !is_integer(rt)) 590 return; 591 592 if (any_query_enabled && !in_system_header) { 593 if (lt == CHAR && rn->tn_op == CON && 594 !rn->tn_val.v_char_constant) { 595 /* comparison '%s' of 'char' with plain integer %d */ 596 query_message(14, 597 op_name(op), (int)rn->tn_val.u.integer); 598 } 599 if (rt == CHAR && ln->tn_op == CON && 600 !ln->tn_val.v_char_constant) { 601 /* comparison '%s' of 'char' with plain integer %d */ 602 query_message(14, 603 op_name(op), (int)ln->tn_val.u.integer); 604 } 605 } 606 607 if (hflag || pflag) { 608 if (lt == CHAR && is_out_of_char_range(rn)) { 609 char buf[128]; 610 (void)snprintf(buf, sizeof(buf), "%s %d", 611 op_name(op), (int)rn->tn_val.u.integer); 612 /* nonportable character comparison '%s' */ 613 warning(230, buf); 614 return; 615 } 616 if (rt == CHAR && is_out_of_char_range(ln)) { 617 char buf[128]; 618 (void)snprintf(buf, sizeof(buf), "%d %s ?", 619 (int)ln->tn_val.u.integer, op_name(op)); 620 /* nonportable character comparison '%s' */ 621 warning(230, buf); 622 return; 623 } 624 } 625 626 if (is_uinteger(lt) && !is_uinteger(rt) && 627 rn->tn_op == CON && rn->tn_val.u.integer <= 0) { 628 if (rn->tn_val.u.integer < 0) { 629 /* operator '%s' compares '%s' with '%s' */ 630 warning(162, op_name(op), 631 type_name(ln->tn_type), "negative constant"); 632 } else if (op == LT || op == GE) { 633 /* operator '%s' compares '%s' with '%s' */ 634 warning(162, op_name(op), type_name(ln->tn_type), "0"); 635 } 636 return; 637 } 638 if (is_uinteger(rt) && !is_uinteger(lt) && 639 ln->tn_op == CON && ln->tn_val.u.integer <= 0) { 640 if (ln->tn_val.u.integer < 0) { 641 /* operator '%s' compares '%s' with '%s' */ 642 warning(162, op_name(op), 643 "negative constant", type_name(rn->tn_type)); 644 } else if (op == GT || op == LE) { 645 /* operator '%s' compares '%s' with '%s' */ 646 warning(162, op_name(op), "0", type_name(rn->tn_type)); 647 } 648 return; 649 } 650 } 651 652 static const tspec_t arith_rank[] = { 653 LDOUBLE, DOUBLE, FLOAT, 654 #ifdef INT128_SIZE 655 UINT128, INT128, 656 #endif 657 ULLONG, LLONG, 658 ULONG, LONG, 659 UINT, INT, 660 }; 661 662 /* Keep unsigned in traditional C */ 663 static tspec_t 664 usual_arithmetic_conversion_trad(tspec_t lt, tspec_t rt) 665 { 666 667 size_t i; 668 for (i = 0; arith_rank[i] != INT; i++) 669 if (lt == arith_rank[i] || rt == arith_rank[i]) 670 break; 671 672 tspec_t t = arith_rank[i]; 673 if (is_uinteger(lt) || is_uinteger(rt)) 674 if (is_integer(t) && !is_uinteger(t)) 675 return unsigned_type(t); 676 return t; 677 } 678 679 static tspec_t 680 usual_arithmetic_conversion_c90(tspec_t lt, tspec_t rt) 681 { 682 683 if (lt == rt) 684 return lt; 685 686 if (lt == LCOMPLEX || rt == LCOMPLEX) 687 return LCOMPLEX; 688 if (lt == DCOMPLEX || rt == DCOMPLEX) 689 return DCOMPLEX; 690 if (lt == FCOMPLEX || rt == FCOMPLEX) 691 return FCOMPLEX; 692 if (lt == LDOUBLE || rt == LDOUBLE) 693 return LDOUBLE; 694 if (lt == DOUBLE || rt == DOUBLE) 695 return DOUBLE; 696 if (lt == FLOAT || rt == FLOAT) 697 return FLOAT; 698 699 /* 700 * If type A has more bits than type B, it should be able to hold all 701 * possible values of type B. 702 */ 703 if (size_in_bits(lt) > size_in_bits(rt)) 704 return lt; 705 if (size_in_bits(lt) < size_in_bits(rt)) 706 return rt; 707 708 size_t i; 709 for (i = 3; arith_rank[i] != INT; i++) 710 if (arith_rank[i] == lt || arith_rank[i] == rt) 711 break; 712 if ((is_uinteger(lt) || is_uinteger(rt)) && 713 !is_uinteger(arith_rank[i])) 714 i--; 715 return arith_rank[i]; 716 } 717 718 static tnode_t * 719 apply_usual_arithmetic_conversions(op_t op, tnode_t *tn, tspec_t t) 720 { 721 type_t *ntp = expr_dup_type(tn->tn_type); 722 ntp->t_tspec = t; 723 if (tn->tn_op != CON) { 724 /* usual arithmetic conversion for '%s' from '%s' to '%s' */ 725 query_message(4, op_name(op), 726 type_name(tn->tn_type), type_name(ntp)); 727 } 728 return convert(op, 0, ntp, tn); 729 } 730 731 /* 732 * Apply the "usual arithmetic conversions" (C99 6.3.1.8), which gives both 733 * operands the same type. 734 */ 735 static void 736 balance(op_t op, tnode_t **lnp, tnode_t **rnp) 737 { 738 739 tspec_t lt = (*lnp)->tn_type->t_tspec; 740 tspec_t rt = (*rnp)->tn_type->t_tspec; 741 if (!is_arithmetic(lt) || !is_arithmetic(rt)) 742 return; 743 744 tspec_t t = allow_c90 745 ? usual_arithmetic_conversion_c90(lt, rt) 746 : usual_arithmetic_conversion_trad(lt, rt); 747 748 if (t != lt) 749 *lnp = apply_usual_arithmetic_conversions(op, *lnp, t); 750 if (t != rt) 751 *rnp = apply_usual_arithmetic_conversions(op, *rnp, t); 752 } 753 754 /* 755 * Create a tree node for the unary & operator 756 */ 757 static tnode_t * 758 build_address(bool sys, tnode_t *tn, bool noign) 759 { 760 tspec_t t; 761 762 if (!noign && ((t = tn->tn_type->t_tspec) == ARRAY || t == FUNC)) { 763 if (!allow_c90) 764 /* '&' before array or function: ignored */ 765 warning(127); 766 return tn; 767 } 768 769 /* eliminate &* */ 770 if (tn->tn_op == INDIR && 771 tn->tn_left->tn_type->t_tspec == PTR && 772 tn->tn_left->tn_type->t_subt == tn->tn_type) { 773 return tn->tn_left; 774 } 775 776 return build_op(ADDR, sys, expr_derive_type(tn->tn_type, PTR), 777 tn, NULL); 778 } 779 780 /* 781 * XXX 782 * Note: There appear to be a number of bugs in detecting overflow in 783 * this function. An audit and a set of proper regression tests are needed. 784 * --Perry Metzger, Nov. 16, 2001 785 */ 786 /* 787 * Do only as much as necessary to compute constant expressions. 788 * Called only if the operator allows folding and all operands are constants. 789 */ 790 static tnode_t * 791 fold(tnode_t *tn) 792 { 793 794 val_t *v = xcalloc(1, sizeof(*v)); 795 v->v_tspec = tn->tn_type->t_tspec; 796 797 tspec_t t = tn->tn_left->tn_type->t_tspec; 798 bool utyp = !is_integer(t) || is_uinteger(t); 799 int64_t sl = tn->tn_left->tn_val.u.integer, sr = 0; 800 uint64_t ul = sl, ur = 0; 801 if (is_binary(tn)) 802 ur = sr = tn->tn_right->tn_val.u.integer; 803 804 int64_t mask = (int64_t)value_bits(size_in_bits(t)); 805 bool ovfl = false; 806 807 int64_t si; 808 switch (tn->tn_op) { 809 case UPLUS: 810 si = sl; 811 break; 812 case UMINUS: 813 si = sl == INT64_MIN ? sl : -sl; 814 if (sl != 0 && msb(si, t) == msb(sl, t)) 815 ovfl = true; 816 break; 817 case COMPL: 818 si = ~sl; 819 break; 820 case MULT: 821 if (utyp) { 822 si = (int64_t)(ul * ur); 823 if (si != (si & mask)) 824 ovfl = true; 825 else if ((ul != 0) && ((si / ul) != ur)) 826 ovfl = true; 827 } else { 828 si = sl * sr; 829 if (msb(si, t) != (msb(sl, t) ^ msb(sr, t))) 830 ovfl = true; 831 } 832 break; 833 case DIV: 834 if (sr == 0) { 835 /* division by 0 */ 836 error(139); 837 si = utyp ? -1 : INT64_MAX; 838 } else { 839 si = utyp ? (int64_t)(ul / ur) : sl / sr; 840 } 841 break; 842 case MOD: 843 if (sr == 0) { 844 /* modulus by 0 */ 845 error(140); 846 si = 0; 847 } else { 848 si = utyp ? (int64_t)(ul % ur) : sl % sr; 849 } 850 break; 851 case PLUS: 852 si = utyp ? (int64_t)(ul + ur) : sl + sr; 853 if (msb(sl, t) && msb(sr, t) && !msb(si, t)) 854 ovfl = true; 855 if (!utyp && !msb(sl, t) && !msb(sr, t) && msb(si, t)) 856 ovfl = true; 857 break; 858 case MINUS: 859 si = utyp ? (int64_t)(ul - ur) : sl - sr; 860 if (!utyp && msb(sl, t) && !msb(sr, t) && !msb(si, t)) 861 ovfl = true; 862 if (!msb(sl, t) && msb(sr, t) && msb(si, t)) 863 ovfl = true; 864 break; 865 case SHL: 866 /* TODO: warn about out-of-bounds 'sr'. */ 867 /* TODO: warn about overflow in signed '<<'. */ 868 si = utyp ? (int64_t)(ul << (sr & 63)) : sl << (sr & 63); 869 break; 870 case SHR: 871 /* 872 * The sign must be explicitly extended because 873 * shifts of signed values are implementation dependent. 874 */ 875 /* TODO: warn about out-of-bounds 'sr'. */ 876 si = (int64_t)(ul >> (sr & 63)); 877 si = convert_integer(si, t, size_in_bits(t) - (int)sr); 878 break; 879 case LT: 880 si = (utyp ? ul < ur : sl < sr) ? 1 : 0; 881 break; 882 case LE: 883 si = (utyp ? ul <= ur : sl <= sr) ? 1 : 0; 884 break; 885 case GE: 886 si = (utyp ? ul >= ur : sl >= sr) ? 1 : 0; 887 break; 888 case GT: 889 si = (utyp ? ul > ur : sl > sr) ? 1 : 0; 890 break; 891 case EQ: 892 si = (utyp ? ul == ur : sl == sr) ? 1 : 0; 893 break; 894 case NE: 895 si = (utyp ? ul != ur : sl != sr) ? 1 : 0; 896 break; 897 case BITAND: 898 si = utyp ? (int64_t)(ul & ur) : sl & sr; 899 break; 900 case BITXOR: 901 si = utyp ? (int64_t)(ul ^ ur) : sl ^ sr; 902 break; 903 case BITOR: 904 si = utyp ? (int64_t)(ul | ur) : sl | sr; 905 break; 906 default: 907 lint_assert(/*CONSTCOND*/false); 908 } 909 910 /* XXX: The overflow check does not work for 64-bit integers. */ 911 if (ovfl || 912 ((uint64_t)(si | mask) != ~(uint64_t)0 && (si & ~mask) != 0)) { 913 if (hflag) 914 /* operator '%s' produces integer overflow */ 915 warning(141, op_name(tn->tn_op)); 916 } 917 918 v->u.integer = convert_integer(si, t, 0); 919 920 tnode_t *cn = build_constant(tn->tn_type, v); 921 if (tn->tn_left->tn_system_dependent) 922 cn->tn_system_dependent = true; 923 if (is_binary(tn) && tn->tn_right->tn_system_dependent) 924 cn->tn_system_dependent = true; 925 926 return cn; 927 } 928 929 /* 930 * Create a new node for one of the operators POINT and ARROW. 931 */ 932 static tnode_t * 933 build_struct_access(op_t op, bool sys, tnode_t *ln, tnode_t *rn) 934 { 935 936 lint_assert(rn->tn_op == NAME); 937 lint_assert(is_member(rn->tn_sym)); 938 939 bool lvalue = op == ARROW || ln->tn_lvalue; 940 941 if (op == POINT) { 942 ln = build_address(sys, ln, true); 943 } else if (ln->tn_type->t_tspec != PTR) { 944 lint_assert(!allow_c90); 945 lint_assert(is_integer(ln->tn_type->t_tspec)); 946 ln = convert(NOOP, 0, expr_derive_type(gettyp(VOID), PTR), ln); 947 } 948 949 tnode_t *ctn = build_integer_constant(PTRDIFF_TSPEC, 950 rn->tn_sym->u.s_member.sm_offset_in_bits / CHAR_SIZE); 951 952 type_t *ptr_tp = expr_derive_type(rn->tn_type, PTR); 953 tnode_t *ntn = build_op(PLUS, sys, ptr_tp, ln, ctn); 954 if (ln->tn_op == CON) 955 ntn = fold(ntn); 956 957 op_t nop = rn->tn_type->t_bitfield ? FSEL : INDIR; 958 ntn = build_op(nop, sys, ntn->tn_type->t_subt, ntn, NULL); 959 if (!lvalue) 960 ntn->tn_lvalue = false; 961 962 return ntn; 963 } 964 965 /* 966 * Get the size in bytes of type tp->t_subt, as a constant expression of type 967 * ptrdiff_t as seen from the target platform. 968 */ 969 static tnode_t * 970 subt_size_in_bytes(type_t *tp) 971 { 972 973 lint_assert(tp->t_tspec == PTR); 974 tp = tp->t_subt; 975 976 int elem = 1; 977 while (tp->t_tspec == ARRAY) { 978 elem *= tp->t_dim; 979 tp = tp->t_subt; 980 } 981 982 int elsz_in_bits = 0; 983 switch (tp->t_tspec) { 984 case FUNC: 985 /* pointer to function is not allowed here */ 986 error(110); 987 break; 988 case VOID: 989 /* cannot do pointer arithmetic on operand of unknown size */ 990 gnuism(136); 991 break; 992 case STRUCT: 993 case UNION: 994 if ((elsz_in_bits = (int)tp->t_sou->sou_size_in_bits) == 0) 995 /* cannot do pointer arithmetic on operand of ... */ 996 error(136); 997 break; 998 case ENUM: 999 if (is_incomplete(tp)) { 1000 /* cannot do pointer arithmetic on operand of ... */ 1001 warning(136); 1002 } 1003 /* FALLTHROUGH */ 1004 default: 1005 if ((elsz_in_bits = size_in_bits(tp->t_tspec)) == 0) { 1006 /* cannot do pointer arithmetic on operand of ... */ 1007 error(136); 1008 } else { 1009 lint_assert(elsz_in_bits != -1); 1010 } 1011 break; 1012 } 1013 1014 if (elem == 0 && elsz_in_bits != 0) { 1015 /* cannot do pointer arithmetic on operand of unknown size */ 1016 error(136); 1017 } 1018 1019 if (elsz_in_bits == 0) 1020 elsz_in_bits = CHAR_SIZE; 1021 1022 return build_integer_constant(PTRDIFF_TSPEC, 1023 (int64_t)(elem * elsz_in_bits / CHAR_SIZE)); 1024 } 1025 1026 /* 1027 * Create a node for INCAFT, INCBEF, DECAFT and DECBEF. 1028 */ 1029 static tnode_t * 1030 build_prepost_incdec(op_t op, bool sys, tnode_t *ln) 1031 { 1032 1033 lint_assert(ln != NULL); 1034 tnode_t *cn = ln->tn_type->t_tspec == PTR 1035 ? subt_size_in_bytes(ln->tn_type) 1036 : build_integer_constant(INT, 1); 1037 return build_op(op, sys, ln->tn_type, ln, cn); 1038 } 1039 1040 static void 1041 check_enum_array_index(const tnode_t *ln, const tnode_t *rn) 1042 { 1043 1044 if (ln->tn_op != ADDR || ln->tn_left->tn_op != NAME) 1045 return; 1046 1047 const type_t *ltp = ln->tn_left->tn_type; 1048 if (ltp->t_tspec != ARRAY || ltp->t_incomplete_array) 1049 return; 1050 1051 if (rn->tn_op != CVT || !rn->tn_type->t_is_enum) 1052 return; 1053 if (rn->tn_left->tn_op != LOAD) 1054 return; 1055 1056 const type_t *rtp = rn->tn_left->tn_type; 1057 const sym_t *ec = rtp->t_enum->en_first_enumerator; 1058 const sym_t *max_ec = ec; 1059 lint_assert(ec != NULL); 1060 for (ec = ec->s_next; ec != NULL; ec = ec->s_next) 1061 if (ec->u.s_enum_constant > max_ec->u.s_enum_constant) 1062 max_ec = ec; 1063 1064 int64_t max_enum_value = max_ec->u.s_enum_constant; 1065 lint_assert(INT_MIN <= max_enum_value && max_enum_value <= INT_MAX); 1066 1067 int max_array_index = ltp->t_dim - 1; 1068 if (max_enum_value == max_array_index) 1069 return; 1070 1071 /* 1072 * If the name of the largest enum constant contains 'MAX' or 'NUM', 1073 * that constant is typically not part of the allowed enum values but 1074 * a marker for the number of actual enum values. 1075 */ 1076 if (max_enum_value == max_array_index + 1 && 1077 (strstr(max_ec->s_name, "MAX") != NULL || 1078 strstr(max_ec->s_name, "max") != NULL || 1079 strstr(max_ec->s_name, "NUM") != NULL || 1080 strstr(max_ec->s_name, "num") != NULL)) 1081 return; 1082 1083 /* maximum value %d of '%s' does not match maximum array index %d */ 1084 warning(348, (int)max_enum_value, type_name(rtp), max_array_index); 1085 print_previous_declaration(max_ec); 1086 } 1087 1088 /* 1089 * Create a node for operators PLUS and MINUS. 1090 */ 1091 static tnode_t * 1092 build_plus_minus(op_t op, bool sys, tnode_t *ln, tnode_t *rn) 1093 { 1094 1095 /* If pointer and integer, move the pointer to the left. */ 1096 if (rn->tn_type->t_tspec == PTR && is_integer(ln->tn_type->t_tspec)) { 1097 tnode_t *tmp = ln; 1098 ln = rn; 1099 rn = tmp; 1100 /* pointer addition has integer on the left-hand side */ 1101 query_message(5); 1102 } 1103 1104 /* pointer +- integer */ 1105 if (ln->tn_type->t_tspec == PTR && rn->tn_type->t_tspec != PTR) { 1106 lint_assert(is_integer(rn->tn_type->t_tspec)); 1107 1108 check_ctype_macro_invocation(ln, rn); 1109 check_enum_array_index(ln, rn); 1110 1111 tnode_t *elsz = subt_size_in_bytes(ln->tn_type); 1112 if (rn->tn_type->t_tspec != elsz->tn_type->t_tspec) 1113 rn = convert(NOOP, 0, elsz->tn_type, rn); 1114 1115 tnode_t *prod = build_op(MULT, sys, rn->tn_type, rn, elsz); 1116 if (rn->tn_op == CON) 1117 prod = fold(prod); 1118 1119 return build_op(op, sys, ln->tn_type, ln, prod); 1120 } 1121 1122 /* pointer - pointer */ 1123 if (rn->tn_type->t_tspec == PTR) { 1124 lint_assert(ln->tn_type->t_tspec == PTR); 1125 lint_assert(op == MINUS); 1126 1127 type_t *ptrdiff = gettyp(PTRDIFF_TSPEC); 1128 tnode_t *raw_diff = build_op(op, sys, ptrdiff, ln, rn); 1129 if (ln->tn_op == CON && rn->tn_op == CON) 1130 raw_diff = fold(raw_diff); 1131 1132 tnode_t *elsz = subt_size_in_bytes(ln->tn_type); 1133 balance(NOOP, &raw_diff, &elsz); 1134 1135 return build_op(DIV, sys, ptrdiff, raw_diff, elsz); 1136 } 1137 1138 return build_op(op, sys, ln->tn_type, ln, rn); 1139 } 1140 1141 /* 1142 * Create a node for operators SHL and SHR. 1143 */ 1144 static tnode_t * 1145 build_bit_shift(op_t op, bool sys, tnode_t *ln, tnode_t *rn) 1146 { 1147 1148 if (!allow_c90 && rn->tn_type->t_tspec != INT) 1149 // XXX: C1978 7.5 says: "Both [operators] perform the usual 1150 // arithmetic conversions on their operands." 1151 // TODO: Add a test to exercise this part of the code. 1152 rn = convert(NOOP, 0, gettyp(INT), rn); 1153 return build_op(op, sys, ln->tn_type, ln, rn); 1154 } 1155 1156 static bool 1157 is_null_pointer(const tnode_t *tn) 1158 { 1159 tspec_t t = tn->tn_type->t_tspec; 1160 1161 // TODO: Investigate how other pointers are stored, in particular, 1162 // whether a pointer constant can have a non-zero value. 1163 // If not, simplify the code below. 1164 return ((t == PTR && tn->tn_type->t_subt->t_tspec == VOID) || 1165 is_integer(t)) 1166 && (tn->tn_op == CON && tn->tn_val.u.integer == 0); 1167 } 1168 1169 /* Return a type based on tp1, with added qualifiers from tp2. */ 1170 static type_t * 1171 merge_qualifiers(type_t *tp1, const type_t *tp2) 1172 { 1173 1174 lint_assert(tp1->t_tspec == PTR); 1175 lint_assert(tp2->t_tspec == PTR); 1176 1177 bool c1 = tp1->t_subt->t_const; 1178 bool c2 = tp2->t_subt->t_const; 1179 bool v1 = tp1->t_subt->t_volatile; 1180 bool v2 = tp2->t_subt->t_volatile; 1181 1182 if (c1 == (c1 | c2) && v1 == (v1 | v2)) 1183 return tp1; 1184 1185 type_t *nstp = expr_dup_type(tp1->t_subt); 1186 nstp->t_const |= c2; 1187 nstp->t_volatile |= v2; 1188 1189 type_t *ntp = expr_dup_type(tp1); 1190 ntp->t_subt = nstp; 1191 return ntp; 1192 } 1193 1194 /* See C99 6.5.15 "Conditional operator". */ 1195 static tnode_t * 1196 build_colon(bool sys, tnode_t *ln, tnode_t *rn) 1197 { 1198 1199 tspec_t lt = ln->tn_type->t_tspec; 1200 tspec_t rt = rn->tn_type->t_tspec; 1201 1202 type_t *tp; 1203 if (is_arithmetic(lt) && is_arithmetic(rt)) { 1204 /* The operands were already balanced in build_binary. */ 1205 tp = ln->tn_type; 1206 } else if (lt == BOOL && rt == BOOL) { 1207 tp = ln->tn_type; 1208 } else if (lt == VOID || rt == VOID) { 1209 tp = gettyp(VOID); 1210 } else if (is_struct_or_union(lt)) { 1211 /* Both types must be identical. */ 1212 lint_assert(is_struct_or_union(rt)); 1213 lint_assert(ln->tn_type->t_sou == rn->tn_type->t_sou); 1214 if (is_incomplete(ln->tn_type)) { 1215 /* unknown operand size, op '%s' */ 1216 error(138, op_name(COLON)); 1217 return NULL; 1218 } 1219 tp = ln->tn_type; 1220 } else if (lt == PTR && is_integer(rt)) { 1221 if (rt != PTRDIFF_TSPEC) 1222 rn = convert(NOOP, 0, gettyp(PTRDIFF_TSPEC), rn); 1223 tp = ln->tn_type; 1224 } else if (rt == PTR && is_integer(lt)) { 1225 if (lt != PTRDIFF_TSPEC) 1226 ln = convert(NOOP, 0, gettyp(PTRDIFF_TSPEC), ln); 1227 tp = rn->tn_type; 1228 } else if (lt == PTR && is_null_pointer(rn)) { 1229 tp = merge_qualifiers(ln->tn_type, rn->tn_type); 1230 } else if (rt == PTR && is_null_pointer(ln)) { 1231 tp = merge_qualifiers(rn->tn_type, ln->tn_type); 1232 } else if (lt == PTR && ln->tn_type->t_subt->t_tspec == VOID) { 1233 tp = merge_qualifiers(ln->tn_type, rn->tn_type); 1234 } else if (rt == PTR && rn->tn_type->t_subt->t_tspec == VOID) { 1235 tp = merge_qualifiers(rn->tn_type, ln->tn_type); 1236 } else { 1237 /* 1238 * XXX For now we simply take the left type. This is 1239 * probably wrong, if one type contains a function prototype 1240 * and the other one, at the same place, only an old-style 1241 * declaration. 1242 */ 1243 tp = merge_qualifiers(ln->tn_type, rn->tn_type); 1244 } 1245 1246 return build_op(COLON, sys, tp, ln, rn); 1247 } 1248 1249 /* TODO: check for varargs */ 1250 static bool 1251 is_cast_redundant(const tnode_t *tn) 1252 { 1253 const type_t *ntp = tn->tn_type, *otp = tn->tn_left->tn_type; 1254 tspec_t nt = ntp->t_tspec, ot = otp->t_tspec; 1255 1256 if (nt == BOOL || ot == BOOL) 1257 return nt == BOOL && ot == BOOL; 1258 1259 if (is_integer(nt) && is_integer(ot)) { 1260 unsigned int nw = width_in_bits(ntp), ow = width_in_bits(otp); 1261 if (is_uinteger(nt) == is_uinteger(ot)) 1262 return nw >= ow; 1263 return is_uinteger(ot) && nw > ow; 1264 } 1265 1266 if (is_complex(nt) || is_complex(ot)) 1267 return is_complex(nt) && is_complex(ot) && 1268 size_in_bits(nt) >= size_in_bits(ot); 1269 1270 if (is_floating(nt) && is_floating(ot)) 1271 return size_in_bits(nt) >= size_in_bits(ot); 1272 1273 if (nt == PTR && ot == PTR) { 1274 if (!ntp->t_subt->t_const && otp->t_subt->t_const) 1275 return false; 1276 if (!ntp->t_subt->t_volatile && otp->t_subt->t_volatile) 1277 return false; 1278 1279 if (ntp->t_subt->t_tspec == VOID || 1280 otp->t_subt->t_tspec == VOID || 1281 types_compatible(ntp->t_subt, otp->t_subt, 1282 false, false, NULL)) 1283 return true; 1284 } 1285 1286 return false; 1287 } 1288 1289 static bool 1290 is_assignment(op_t op) 1291 { 1292 1293 return op == ASSIGN || 1294 op == MULASS || 1295 op == DIVASS || 1296 op == MODASS || 1297 op == ADDASS || 1298 op == SUBASS || 1299 op == SHLASS || 1300 op == SHRASS || 1301 op == ANDASS || 1302 op == XORASS || 1303 op == ORASS || 1304 op == RETURN || 1305 op == INIT; 1306 } 1307 1308 /* Create a node for an assignment operator (both '=' and 'op='). */ 1309 static tnode_t * 1310 build_assignment(op_t op, bool sys, tnode_t *ln, tnode_t *rn) 1311 { 1312 1313 tspec_t lt = ln->tn_type->t_tspec; 1314 tspec_t rt = rn->tn_type->t_tspec; 1315 1316 if (any_query_enabled && is_assignment(rn->tn_op)) { 1317 /* chained assignment with '%s' and '%s' */ 1318 query_message(10, op_name(op), op_name(rn->tn_op)); 1319 } 1320 1321 if ((op == ADDASS || op == SUBASS) && lt == PTR) { 1322 lint_assert(is_integer(rt)); 1323 tnode_t *ctn = subt_size_in_bytes(ln->tn_type); 1324 if (rn->tn_type->t_tspec != ctn->tn_type->t_tspec) 1325 rn = convert(NOOP, 0, ctn->tn_type, rn); 1326 rn = build_op(MULT, sys, rn->tn_type, rn, ctn); 1327 if (rn->tn_left->tn_op == CON) 1328 rn = fold(rn); 1329 } 1330 1331 if ((op == ASSIGN || op == RETURN || op == INIT) && 1332 (lt == STRUCT || rt == STRUCT)) { 1333 lint_assert(lt == rt); 1334 lint_assert(ln->tn_type->t_sou == rn->tn_type->t_sou); 1335 if (is_incomplete(ln->tn_type)) { 1336 if (op == RETURN) { 1337 /* cannot return incomplete type */ 1338 error(212); 1339 } else { 1340 /* unknown operand size, op '%s' */ 1341 error(138, op_name(op)); 1342 } 1343 return NULL; 1344 } 1345 } 1346 1347 if (op == SHLASS && hflag && allow_trad && allow_c90 1348 && portable_rank_cmp(lt, rt) < 0) 1349 /* semantics of '%s' change in C90; ... */ 1350 warning(118, "<<="); 1351 1352 if (op != SHLASS && op != SHRASS 1353 && (op == ASSIGN || lt != PTR) 1354 && (lt != rt || (ln->tn_type->t_bitfield && rn->tn_op == CON))) { 1355 rn = convert(op, 0, ln->tn_type, rn); 1356 rt = lt; 1357 } 1358 1359 if (any_query_enabled && rn->tn_op == CVT && rn->tn_cast && 1360 types_compatible(ln->tn_type, rn->tn_type, false, false, NULL) && 1361 is_cast_redundant(rn)) { 1362 /* redundant cast from '%s' to '%s' before assignment */ 1363 query_message(7, 1364 type_name(rn->tn_left->tn_type), type_name(rn->tn_type)); 1365 } 1366 1367 return build_op(op, sys, ln->tn_type, ln, rn); 1368 } 1369 1370 /* 1371 * Create a node for REAL, IMAG 1372 */ 1373 static tnode_t * 1374 build_real_imag(op_t op, bool sys, tnode_t *ln) 1375 { 1376 1377 lint_assert(ln != NULL); 1378 if (ln->tn_op == NAME) { 1379 /* 1380 * This may be too much, but it avoids wrong warnings. 1381 * See d_c99_complex_split.c. 1382 */ 1383 mark_as_used(ln->tn_sym, false, false); 1384 mark_as_set(ln->tn_sym); 1385 } 1386 1387 tspec_t t; 1388 switch (ln->tn_type->t_tspec) { 1389 case LCOMPLEX: 1390 t = LDOUBLE; 1391 break; 1392 case DCOMPLEX: 1393 t = DOUBLE; 1394 break; 1395 case FCOMPLEX: 1396 t = FLOAT; 1397 break; 1398 default: 1399 /* '__%s__' is illegal for type '%s' */ 1400 error(276, op == REAL ? "real" : "imag", 1401 type_name(ln->tn_type)); 1402 return NULL; 1403 } 1404 1405 tnode_t *ntn = build_op(op, sys, gettyp(t), ln, NULL); 1406 ntn->tn_lvalue = true; 1407 return ntn; 1408 } 1409 1410 static bool 1411 is_confusing_precedence(op_t op, op_t lop, bool lparen, op_t rop, bool rparen) 1412 { 1413 1414 if (op == SHL || op == SHR) { 1415 if (!lparen && (lop == PLUS || lop == MINUS)) 1416 return true; 1417 if (!rparen && (rop == PLUS || rop == MINUS)) 1418 return true; 1419 return false; 1420 } 1421 1422 if (op == LOGOR) { 1423 if (!lparen && lop == LOGAND) 1424 return true; 1425 if (!rparen && rop == LOGAND) 1426 return true; 1427 return false; 1428 } 1429 1430 lint_assert(op == BITAND || op == BITXOR || op == BITOR); 1431 if (!lparen && lop != op) { 1432 if (lop == PLUS || lop == MINUS) 1433 return true; 1434 if (lop == BITAND || lop == BITXOR) 1435 return true; 1436 } 1437 if (!rparen && rop != op) { 1438 if (rop == PLUS || rop == MINUS) 1439 return true; 1440 if (rop == BITAND || rop == BITXOR) 1441 return true; 1442 } 1443 return false; 1444 } 1445 1446 /* 1447 * Print a warning if the given node has operands which should be 1448 * parenthesized. 1449 * 1450 * XXX Does not work if an operand is a constant expression. Constant 1451 * expressions are already folded. 1452 */ 1453 static void 1454 check_precedence_confusion(tnode_t *tn) 1455 { 1456 tnode_t *ln, *rn; 1457 1458 if (!hflag) 1459 return; 1460 1461 debug_node(tn); 1462 1463 lint_assert(is_binary(tn)); 1464 for (ln = tn->tn_left; ln->tn_op == CVT; ln = ln->tn_left) 1465 continue; 1466 for (rn = tn->tn_right; rn->tn_op == CVT; rn = rn->tn_left) 1467 continue; 1468 1469 if (is_confusing_precedence(tn->tn_op, 1470 ln->tn_op, ln->tn_parenthesized, 1471 rn->tn_op, rn->tn_parenthesized)) { 1472 /* precedence confusion possible: parenthesize! */ 1473 warning(169); 1474 } 1475 } 1476 1477 /* 1478 * Fold constant nodes, as much as is needed for comparing the value with 0. 1479 */ 1480 static tnode_t * 1481 fold_bool(tnode_t *tn) 1482 { 1483 1484 val_t *v = xcalloc(1, sizeof(*v)); 1485 v->v_tspec = tn->tn_type->t_tspec; 1486 lint_assert(v->v_tspec == INT || (Tflag && v->v_tspec == BOOL)); 1487 1488 bool l = constant_is_nonzero(tn->tn_left); 1489 bool r = is_binary(tn) && constant_is_nonzero(tn->tn_right); 1490 1491 switch (tn->tn_op) { 1492 case NOT: 1493 if (hflag && !suppress_constcond) 1494 /* constant operand to '!' */ 1495 warning(239); 1496 v->u.integer = !l ? 1 : 0; 1497 break; 1498 case LOGAND: 1499 v->u.integer = l && r ? 1 : 0; 1500 break; 1501 case LOGOR: 1502 v->u.integer = l || r ? 1 : 0; 1503 break; 1504 default: 1505 lint_assert(/*CONSTCOND*/false); 1506 } 1507 1508 return build_constant(tn->tn_type, v); 1509 } 1510 1511 static long double 1512 floating_error_value(tspec_t t, long double lv) 1513 { 1514 if (t == FLOAT) 1515 return lv < 0 ? -FLT_MAX : FLT_MAX; 1516 if (t == DOUBLE) 1517 return lv < 0 ? -DBL_MAX : DBL_MAX; 1518 /* 1519 * When NetBSD is cross-built in MKLINT=yes mode on x86_64 for 1520 * sparc64, tools/lint checks this code while building usr.bin/xlint. 1521 * In that situation, lint uses the preprocessor for sparc64, in which 1522 * the type 'long double' is IEEE-754-binary128, affecting the macro 1523 * LDBL_MAX below. The type 'long double', as well as the strtold 1524 * implementation, comes from the host platform x86_64 though, where 1525 * 'long double' consumes 128 bits as well but only uses 80 of them. 1526 * The exponent range of the two 'long double' types is the same, but 1527 * the maximum finite value differs due to the extended precision on 1528 * sparc64. 1529 * 1530 * To properly handle the data types of the target platform, lint 1531 * would have to implement the floating-point types in a 1532 * platform-independent way, which is not worth the effort, given how 1533 * few programs practically use 'long double'. 1534 */ 1535 /* LINTED 248: floating-point constant out of range */ 1536 long double max = LDBL_MAX; 1537 return lv < 0 ? -max : max; 1538 } 1539 1540 static bool 1541 is_floating_overflow(tspec_t t, long double val) 1542 { 1543 if (fpe != 0 || isfinite(val) == 0) 1544 return true; 1545 if (t == FLOAT && (val > FLT_MAX || val < -FLT_MAX)) 1546 return true; 1547 if (t == DOUBLE && (val > DBL_MAX || val < -DBL_MAX)) 1548 return true; 1549 return false; 1550 } 1551 1552 /* 1553 * Fold constant nodes having operands with floating point type. 1554 */ 1555 static tnode_t * 1556 fold_float(tnode_t *tn) 1557 { 1558 1559 fpe = 0; 1560 1561 tspec_t t = tn->tn_type->t_tspec; 1562 1563 val_t *v = xcalloc(1, sizeof(*v)); 1564 v->v_tspec = t; 1565 1566 lint_assert(is_floating(t)); 1567 lint_assert(t == tn->tn_left->tn_type->t_tspec); 1568 lint_assert(!is_binary(tn) || t == tn->tn_right->tn_type->t_tspec); 1569 1570 long double lv = tn->tn_left->tn_val.u.floating; 1571 long double rv = is_binary(tn) ? tn->tn_right->tn_val.u.floating : 0.0; 1572 1573 switch (tn->tn_op) { 1574 case UPLUS: 1575 v->u.floating = lv; 1576 break; 1577 case UMINUS: 1578 v->u.floating = -lv; 1579 break; 1580 case MULT: 1581 v->u.floating = lv * rv; 1582 break; 1583 case DIV: 1584 if (rv == 0.0) { 1585 /* division by 0 */ 1586 error(139); 1587 v->u.floating = floating_error_value(t, lv); 1588 } else { 1589 v->u.floating = lv / rv; 1590 } 1591 break; 1592 case PLUS: 1593 v->u.floating = lv + rv; 1594 break; 1595 case MINUS: 1596 v->u.floating = lv - rv; 1597 break; 1598 case LT: 1599 v->u.integer = lv < rv ? 1 : 0; 1600 break; 1601 case LE: 1602 v->u.integer = lv <= rv ? 1 : 0; 1603 break; 1604 case GE: 1605 v->u.integer = lv >= rv ? 1 : 0; 1606 break; 1607 case GT: 1608 v->u.integer = lv > rv ? 1 : 0; 1609 break; 1610 case EQ: 1611 v->u.integer = lv == rv ? 1 : 0; 1612 break; 1613 case NE: 1614 v->u.integer = lv != rv ? 1 : 0; 1615 break; 1616 default: 1617 lint_assert(/*CONSTCOND*/false); 1618 } 1619 1620 // XXX: Must not access u.floating after setting u.integer. 1621 lint_assert(fpe != 0 || isnan(v->u.floating) == 0); 1622 if (is_complex(v->v_tspec)) { 1623 /* 1624 * Don't warn, as lint doesn't model the imaginary part of 1625 * complex numbers. 1626 */ 1627 fpe = 0; 1628 } else if (is_floating_overflow(t, v->u.floating)) { 1629 /* operator '%s' produces floating point overflow */ 1630 warning(142, op_name(tn->tn_op)); 1631 v->u.floating = floating_error_value(t, v->u.floating); 1632 fpe = 0; 1633 } 1634 1635 return build_constant(tn->tn_type, v); 1636 } 1637 1638 static void 1639 use(const tnode_t *tn) 1640 { 1641 if (tn == NULL) 1642 return; 1643 switch (tn->tn_op) { 1644 case NAME: 1645 mark_as_used(tn->tn_sym, false /* XXX */, false /* XXX */); 1646 break; 1647 case CON: 1648 case STRING: 1649 break; 1650 default: 1651 use(tn->tn_left); 1652 if (is_binary(tn) || tn->tn_op == PUSH) 1653 use(tn->tn_right); 1654 } 1655 } 1656 1657 /* 1658 * Create a tree node for a binary operator and its two operands. Also called 1659 * for unary operators; in that case rn is NULL. 1660 * 1661 * Function calls, sizeof and casts are handled elsewhere. 1662 */ 1663 tnode_t * 1664 build_binary(tnode_t *ln, op_t op, bool sys, tnode_t *rn) 1665 { 1666 const mod_t *mp = &modtab[op]; 1667 1668 /* If there was an error in one of the operands, return. */ 1669 if (ln == NULL || (mp->m_binary && rn == NULL)) 1670 return NULL; 1671 1672 /* 1673 * Apply class conversions to the left operand, but only if its 1674 * value is needed or compared with zero. 1675 */ 1676 if (mp->m_value_context || mp->m_compares_with_zero) 1677 ln = cconv(ln); 1678 /* 1679 * The right operand is almost always in a test or value context, 1680 * except if it is a struct or union member. 1681 */ 1682 if (mp->m_binary && op != ARROW && op != POINT) 1683 rn = cconv(rn); 1684 1685 /* 1686 * Print some warnings for comparisons of unsigned values with 1687 * constants lower than or equal to null. This must be done 1688 * before promote() because otherwise unsigned char and unsigned 1689 * short would be promoted to int. Types are also tested to be 1690 * CHAR, which would also become int. 1691 */ 1692 if (mp->m_comparison) 1693 check_integer_comparison(op, ln, rn); 1694 1695 if (mp->m_value_context || mp->m_compares_with_zero) 1696 ln = promote(op, false, ln); 1697 if (mp->m_binary && op != ARROW && op != POINT && 1698 op != ASSIGN && op != RETURN && op != INIT) { 1699 rn = promote(op, false, rn); 1700 } 1701 1702 /* 1703 * If the result of the operation is different for signed or 1704 * unsigned operands and one of the operands is signed only in 1705 * C90, print a warning. 1706 */ 1707 if (mp->m_warn_if_left_unsigned_in_c90 && 1708 ln->tn_op == CON && ln->tn_val.v_unsigned_since_c90) { 1709 /* C90 treats constant as unsigned, op '%s' */ 1710 warning(218, op_name(op)); 1711 ln->tn_val.v_unsigned_since_c90 = false; 1712 } 1713 if (mp->m_warn_if_right_unsigned_in_c90 && 1714 rn->tn_op == CON && rn->tn_val.v_unsigned_since_c90) { 1715 /* C90 treats constant as unsigned, op '%s' */ 1716 warning(218, op_name(op)); 1717 rn->tn_val.v_unsigned_since_c90 = false; 1718 } 1719 1720 /* Make sure both operands are of the same type */ 1721 if (mp->m_balance_operands || (!allow_c90 && (op == SHL || op == SHR))) 1722 balance(op, &ln, &rn); 1723 1724 /* 1725 * Check types for compatibility with the operation and mutual 1726 * compatibility. Return if there are serious problems. 1727 */ 1728 if (!typeok(op, 0, ln, rn)) 1729 return NULL; 1730 1731 /* And now create the node. */ 1732 tnode_t *ntn; 1733 switch (op) { 1734 case POINT: 1735 case ARROW: 1736 ntn = build_struct_access(op, sys, ln, rn); 1737 break; 1738 case INCAFT: 1739 case DECAFT: 1740 case INCBEF: 1741 case DECBEF: 1742 ntn = build_prepost_incdec(op, sys, ln); 1743 break; 1744 case ADDR: 1745 ntn = build_address(sys, ln, false); 1746 break; 1747 case INDIR: 1748 ntn = build_op(INDIR, sys, ln->tn_type->t_subt, ln, NULL); 1749 break; 1750 case PLUS: 1751 case MINUS: 1752 ntn = build_plus_minus(op, sys, ln, rn); 1753 break; 1754 case SHL: 1755 case SHR: 1756 ntn = build_bit_shift(op, sys, ln, rn); 1757 break; 1758 case COLON: 1759 ntn = build_colon(sys, ln, rn); 1760 break; 1761 case ASSIGN: 1762 case MULASS: 1763 case DIVASS: 1764 case MODASS: 1765 case ADDASS: 1766 case SUBASS: 1767 case SHLASS: 1768 case SHRASS: 1769 case ANDASS: 1770 case XORASS: 1771 case ORASS: 1772 case RETURN: 1773 case INIT: 1774 ntn = build_assignment(op, sys, ln, rn); 1775 break; 1776 case COMMA: 1777 if (any_query_enabled) { 1778 /* comma operator with types '%s' and '%s' */ 1779 query_message(12, 1780 type_name(ln->tn_type), type_name(rn->tn_type)); 1781 } 1782 /* FALLTHROUGH */ 1783 case QUEST: 1784 ntn = build_op(op, sys, rn->tn_type, ln, rn); 1785 break; 1786 case REAL: 1787 case IMAG: 1788 ntn = build_real_imag(op, sys, ln); 1789 break; 1790 default: 1791 lint_assert(mp->m_binary == (rn != NULL)); 1792 type_t *rettp = mp->m_returns_bool 1793 ? gettyp(Tflag ? BOOL : INT) : ln->tn_type; 1794 ntn = build_op(op, sys, rettp, ln, rn); 1795 break; 1796 } 1797 1798 /* Return if an error occurred. */ 1799 if (ntn == NULL) 1800 return NULL; 1801 1802 /* Print a warning if precedence confusion is possible */ 1803 if (mp->m_possible_precedence_confusion) 1804 check_precedence_confusion(ntn); 1805 1806 /* 1807 * Print a warning if one of the operands is in a context where 1808 * it is compared with zero and if this operand is a constant. 1809 */ 1810 if (hflag && !suppress_constcond && 1811 mp->m_compares_with_zero && 1812 (ln->tn_op == CON || 1813 ((mp->m_binary && op != QUEST) && rn->tn_op == CON)) && 1814 /* XXX: rn->tn_system_dependent should be checked as well */ 1815 !ln->tn_system_dependent) { 1816 /* constant in conditional context */ 1817 warning(161); 1818 } 1819 1820 /* Fold if the operator requires it */ 1821 if (mp->m_fold_constant_operands) { 1822 if (ln->tn_op == CON && (!mp->m_binary || rn->tn_op == CON)) { 1823 if (mp->m_compares_with_zero) { 1824 ntn = fold_bool(ntn); 1825 } else if (is_floating(ntn->tn_type->t_tspec)) { 1826 ntn = fold_float(ntn); 1827 } else { 1828 ntn = fold(ntn); 1829 } 1830 } else if (op == QUEST && ln->tn_op == CON) { 1831 use(ln->tn_val.u.integer != 0 1832 ? rn->tn_right : rn->tn_left); 1833 ntn = ln->tn_val.u.integer != 0 1834 ? rn->tn_left : rn->tn_right; 1835 } 1836 } 1837 1838 return ntn; 1839 } 1840 1841 tnode_t * 1842 build_unary(op_t op, bool sys, tnode_t *tn) 1843 { 1844 return build_binary(tn, op, sys, NULL); 1845 } 1846 1847 static bool 1848 are_members_compatible(const sym_t *a, const sym_t *b) 1849 { 1850 if (a->u.s_member.sm_offset_in_bits != b->u.s_member.sm_offset_in_bits) 1851 return false; 1852 1853 const type_t *atp = a->s_type; 1854 const type_t *btp = b->s_type; 1855 bool w = false; 1856 if (!types_compatible(atp, btp, false, false, &w) && !w) 1857 return false; 1858 if (a->s_bitfield != b->s_bitfield) 1859 return false; 1860 if (a->s_bitfield) { 1861 if (atp->t_bit_field_width != btp->t_bit_field_width) 1862 return false; 1863 if (atp->t_bit_field_offset != btp->t_bit_field_offset) 1864 return false; 1865 } 1866 return true; 1867 } 1868 1869 /* 1870 * Return whether all struct/union members with the same name have the same 1871 * type and offset. 1872 */ 1873 static bool 1874 all_members_compatible(const sym_t *msym) 1875 { 1876 for (const sym_t *csym = msym; 1877 csym != NULL; csym = csym->s_symtab_next) { 1878 if (!is_member(csym)) 1879 continue; 1880 if (strcmp(msym->s_name, csym->s_name) != 0) 1881 continue; 1882 1883 for (const sym_t *sym = csym->s_symtab_next; 1884 sym != NULL; sym = sym->s_symtab_next) { 1885 if (is_member(sym) 1886 && strcmp(csym->s_name, sym->s_name) == 0 1887 && !are_members_compatible(csym, sym)) 1888 return false; 1889 } 1890 } 1891 return true; 1892 } 1893 1894 sym_t * 1895 find_member(const struct_or_union *sou, const char *name) 1896 { 1897 for (sym_t *mem = sou->sou_first_member; 1898 mem != NULL; mem = mem->s_next) { 1899 lint_assert(is_member(mem)); 1900 lint_assert(mem->u.s_member.sm_containing_type == sou); 1901 if (strcmp(mem->s_name, name) == 0) 1902 return mem; 1903 } 1904 1905 for (sym_t *mem = sou->sou_first_member; 1906 mem != NULL; mem = mem->s_next) { 1907 if (is_struct_or_union(mem->s_type->t_tspec) 1908 && mem->s_name == unnamed) { 1909 sym_t *nested_mem = 1910 find_member(mem->s_type->t_sou, name); 1911 if (nested_mem != NULL) 1912 return nested_mem; 1913 } 1914 } 1915 return NULL; 1916 } 1917 1918 /* 1919 * Remove the member if it was unknown until now, which means 1920 * that no defined struct or union has a member with the same name. 1921 */ 1922 static void 1923 remove_unknown_member(tnode_t *tn, sym_t *msym) 1924 { 1925 /* type '%s' does not have member '%s' */ 1926 error(101, type_name(tn->tn_type), msym->s_name); 1927 rmsym(msym); 1928 msym->s_kind = FMEMBER; 1929 msym->s_scl = STRUCT_MEMBER; 1930 1931 struct_or_union *sou = expr_zero_alloc(sizeof(*sou), 1932 "struct_or_union"); 1933 sou->sou_tag = expr_zero_alloc(sizeof(*sou->sou_tag), "sym"); 1934 sou->sou_tag->s_name = unnamed; 1935 1936 msym->u.s_member.sm_containing_type = sou; 1937 /* 1938 * The member sm_offset_in_bits is not needed here since this 1939 * symbol can only be used for error reporting. 1940 */ 1941 } 1942 1943 /* 1944 * Returns a symbol which has the same name as 'msym' and is a member of the 1945 * struct or union specified by 'tn'. 1946 */ 1947 static sym_t * 1948 struct_or_union_member(tnode_t *tn, op_t op, sym_t *msym) 1949 { 1950 1951 /* Determine the tag type of which msym is expected to be a member. */ 1952 const type_t *tp = NULL; 1953 if (op == POINT && is_struct_or_union(tn->tn_type->t_tspec)) 1954 tp = tn->tn_type; 1955 if (op == ARROW && tn->tn_type->t_tspec == PTR 1956 && is_struct_or_union(tn->tn_type->t_subt->t_tspec)) 1957 tp = tn->tn_type->t_subt; 1958 struct_or_union *sou = tp != NULL ? tp->t_sou : NULL; 1959 1960 if (sou != NULL) { 1961 sym_t *nested_mem = find_member(sou, msym->s_name); 1962 if (nested_mem != NULL) 1963 return nested_mem; 1964 } 1965 1966 if (msym->s_scl == NOSCL) { 1967 remove_unknown_member(tn, msym); 1968 return msym; 1969 } 1970 1971 bool eq = all_members_compatible(msym); 1972 1973 /* 1974 * Now handle the case in which the left operand refers really 1975 * to a struct/union, but the right operand is not member of it. 1976 */ 1977 if (sou != NULL) { 1978 if (eq && !allow_c90) { 1979 /* illegal use of member '%s' */ 1980 warning(102, msym->s_name); 1981 } else { 1982 /* illegal use of member '%s' */ 1983 error(102, msym->s_name); 1984 } 1985 return msym; 1986 } 1987 1988 /* 1989 * Now the left operand of ARROW does not point to a struct/union 1990 * or the left operand of POINT is no struct/union. 1991 */ 1992 if (eq) { 1993 if (op == POINT) { 1994 if (!allow_c90) { 1995 /* left operand of '.' must be struct ... */ 1996 warning(103, type_name(tn->tn_type)); 1997 } else { 1998 /* left operand of '.' must be struct ... */ 1999 error(103, type_name(tn->tn_type)); 2000 } 2001 } else { 2002 if (!allow_c90 && tn->tn_type->t_tspec == PTR) { 2003 /* left operand of '->' must be pointer ... */ 2004 warning(104, type_name(tn->tn_type)); 2005 } else { 2006 /* left operand of '->' must be pointer ... */ 2007 error(104, type_name(tn->tn_type)); 2008 } 2009 } 2010 } else { 2011 if (!allow_c90) { 2012 /* non-unique member requires struct/union %s */ 2013 error(105, op == POINT ? "object" : "pointer"); 2014 } else { 2015 /* unacceptable operand of '%s' */ 2016 error(111, op_name(op)); 2017 } 2018 } 2019 2020 return msym; 2021 } 2022 2023 tnode_t * 2024 build_member_access(tnode_t *ln, op_t op, bool sys, sbuf_t *member) 2025 { 2026 sym_t *msym; 2027 2028 if (ln == NULL) 2029 return NULL; 2030 2031 if (op == ARROW) { 2032 /* must do this before struct_or_union_member is called */ 2033 ln = cconv(ln); 2034 } 2035 msym = struct_or_union_member(ln, op, getsym(member)); 2036 return build_binary(ln, op, sys, build_name(msym, false)); 2037 } 2038 2039 /* 2040 * Perform class conversions. 2041 * 2042 * Arrays of type T are converted into pointers to type T. 2043 * Functions are converted to pointers to functions. 2044 * Lvalues are converted to rvalues. 2045 * 2046 * C99 6.3 "Conversions" 2047 * C99 6.3.2 "Other operands" 2048 * C99 6.3.2.1 "Lvalues, arrays, and function designators" 2049 */ 2050 tnode_t * 2051 cconv(tnode_t *tn) 2052 { 2053 /* 2054 * Array-lvalue (array of type T) is converted into rvalue 2055 * (pointer to type T) 2056 */ 2057 if (tn->tn_type->t_tspec == ARRAY) { 2058 if (!tn->tn_lvalue) { 2059 /* XXX print correct operator */ 2060 /* %soperand of '%s' must be lvalue */ 2061 gnuism(114, "", op_name(ADDR)); 2062 } 2063 tn = build_op(ADDR, tn->tn_sys, 2064 expr_derive_type(tn->tn_type->t_subt, PTR), tn, NULL); 2065 } 2066 2067 /* 2068 * Expression of type function (function with return value of type T) 2069 * in rvalue-expression (pointer to function with return value 2070 * of type T) 2071 */ 2072 if (tn->tn_type->t_tspec == FUNC) 2073 tn = build_address(tn->tn_sys, tn, true); 2074 2075 /* lvalue to rvalue */ 2076 if (tn->tn_lvalue) { 2077 type_t *tp = expr_dup_type(tn->tn_type); 2078 /* C99 6.3.2.1p2 sentence 2 says to remove the qualifiers. */ 2079 tp->t_const = tp->t_volatile = false; 2080 tn = build_op(LOAD, tn->tn_sys, tp, tn, NULL); 2081 } 2082 2083 return tn; 2084 } 2085 2086 const tnode_t * 2087 before_conversion(const tnode_t *tn) 2088 { 2089 while (tn->tn_op == CVT && !tn->tn_cast) 2090 tn = tn->tn_left; 2091 return tn; 2092 } 2093 2094 /* 2095 * Most errors required by C90 are reported in struct_or_union_member(). 2096 * Here we only check for totally wrong things. 2097 */ 2098 static bool 2099 typeok_point(const tnode_t *ln, const type_t *ltp, tspec_t lt) 2100 { 2101 if (is_struct_or_union(lt)) 2102 return true; 2103 2104 if (lt == FUNC || lt == VOID || ltp->t_bitfield) 2105 goto wrong; 2106 2107 /* 2108 * Some C dialects from before C90 tolerated any lvalue on the 2109 * left-hand side of the '.' operator, allowing things like 2110 * char st[100]; st.st_mtime, assuming that the member 'st_mtime' 2111 * only occurred in a single struct; see typeok_arrow. 2112 */ 2113 if (ln->tn_lvalue) 2114 return true; 2115 2116 wrong: 2117 /* With allow_c90 we already got an error */ 2118 if (!allow_c90) 2119 /* unacceptable operand of '%s' */ 2120 error(111, op_name(POINT)); 2121 2122 return false; 2123 } 2124 2125 static bool 2126 typeok_arrow(tspec_t lt) 2127 { 2128 /* 2129 * C1978 Appendix A 14.1 says: <quote>In fact, any lvalue is allowed 2130 * before '.', and that lvalue is then assumed to have the form of 2131 * the structure of which the name of the right is a member. [...] 2132 * Such constructions are non-portable.</quote> 2133 */ 2134 if (lt == PTR || (!allow_c90 && is_integer(lt))) 2135 return true; 2136 2137 /* With allow_c90 we already got an error */ 2138 if (!allow_c90) 2139 /* unacceptable operand of '%s' */ 2140 error(111, op_name(ARROW)); 2141 return false; 2142 } 2143 2144 static bool 2145 typeok_incdec(op_t op, const tnode_t *tn, const type_t *tp) 2146 { 2147 /* operand has scalar type (checked in typeok) */ 2148 if (!tn->tn_lvalue) { 2149 if (tn->tn_op == CVT && tn->tn_cast && 2150 tn->tn_left->tn_op == LOAD) { 2151 /* a cast does not yield an lvalue */ 2152 error(163); 2153 } 2154 /* %soperand of '%s' must be lvalue */ 2155 error(114, "", op_name(op)); 2156 return false; 2157 } 2158 if (tp->t_const && allow_c90) { 2159 /* %soperand of '%s' must be modifiable lvalue */ 2160 warning(115, "", op_name(op)); 2161 } 2162 return true; 2163 } 2164 2165 static bool 2166 typeok_address(op_t op, const tnode_t *tn, const type_t *tp, tspec_t t) 2167 { 2168 if (t == ARRAY || t == FUNC) { 2169 /* ok, a warning comes later (in build_address()) */ 2170 } else if (!tn->tn_lvalue) { 2171 if (tn->tn_op == CVT && tn->tn_cast && 2172 tn->tn_left->tn_op == LOAD) { 2173 /* a cast does not yield an lvalue */ 2174 error(163); 2175 } 2176 /* %soperand of '%s' must be lvalue */ 2177 error(114, "", op_name(op)); 2178 return false; 2179 } else if (is_scalar(t)) { 2180 if (tp->t_bitfield) { 2181 /* cannot take address of bit-field */ 2182 error(112); 2183 return false; 2184 } 2185 } else if (t != STRUCT && t != UNION) { 2186 /* unacceptable operand of '%s' */ 2187 error(111, op_name(op)); 2188 return false; 2189 } 2190 if (tn->tn_op == NAME && tn->tn_sym->s_register) { 2191 /* cannot take address of register '%s' */ 2192 error(113, tn->tn_sym->s_name); 2193 return false; 2194 } 2195 return true; 2196 } 2197 2198 static bool 2199 typeok_indir(const type_t *tp, tspec_t t) 2200 { 2201 2202 if (t != PTR) { 2203 /* cannot dereference non-pointer type '%s' */ 2204 error(96, type_name(tp)); 2205 return false; 2206 } 2207 return true; 2208 } 2209 2210 static void 2211 warn_incompatible_types(op_t op, 2212 const type_t *ltp, tspec_t lt, 2213 const type_t *rtp, tspec_t rt) 2214 { 2215 bool binary = modtab[op].m_binary; 2216 2217 if (lt == VOID || (binary && rt == VOID)) { 2218 /* void type illegal in expression */ 2219 error(109); 2220 } else if (op == ASSIGN) { 2221 /* cannot assign to '%s' from '%s' */ 2222 error(171, type_name(ltp), type_name(rtp)); 2223 } else if (binary) { 2224 /* operands of '%s' have incompatible types '%s' and '%s' */ 2225 error(107, op_name(op), type_name(ltp), type_name(rtp)); 2226 } else { 2227 lint_assert(rt == NO_TSPEC); 2228 /* operand of '%s' has invalid type '%s' */ 2229 error(108, op_name(op), type_name(ltp)); 2230 } 2231 } 2232 2233 static bool 2234 typeok_plus(op_t op, 2235 const type_t *ltp, tspec_t lt, 2236 const type_t *rtp, tspec_t rt) 2237 { 2238 /* operands have scalar types (checked in typeok) */ 2239 if ((lt == PTR && !is_integer(rt)) || (rt == PTR && !is_integer(lt))) { 2240 warn_incompatible_types(op, ltp, lt, rtp, rt); 2241 return false; 2242 } 2243 return true; 2244 } 2245 2246 static bool 2247 typeok_minus(op_t op, 2248 const type_t *ltp, tspec_t lt, 2249 const type_t *rtp, tspec_t rt) 2250 { 2251 /* operands have scalar types (checked in typeok) */ 2252 if ((lt == PTR && rt != PTR && !is_integer(rt)) || 2253 (lt != PTR && rt == PTR)) { 2254 warn_incompatible_types(op, ltp, lt, rtp, rt); 2255 return false; 2256 } 2257 if (lt == PTR && rt == PTR && 2258 !types_compatible(ltp->t_subt, rtp->t_subt, true, false, NULL)) { 2259 /* illegal pointer subtraction */ 2260 error(116); 2261 } 2262 return true; 2263 } 2264 2265 static void 2266 typeok_shr(op_t op, 2267 const tnode_t *ln, tspec_t lt, 2268 const tnode_t *rn, tspec_t rt) 2269 { 2270 tspec_t olt = before_conversion(ln)->tn_type->t_tspec; 2271 tspec_t ort = before_conversion(rn)->tn_type->t_tspec; 2272 2273 /* operands have integer types (checked in typeok) */ 2274 if (pflag && !is_uinteger(olt)) { 2275 integer_constraints lc = ic_expr(ln); 2276 if (!ic_maybe_signed(ln->tn_type, &lc)) 2277 return; 2278 2279 /* 2280 * The left operand is signed. This means that 2281 * the operation is (possibly) nonportable. 2282 */ 2283 if (ln->tn_op != CON) { 2284 /* bitwise '%s' on signed value possibly nonportable */ 2285 warning(117, op_name(op)); 2286 } else if (ln->tn_val.u.integer < 0) { 2287 /* bitwise '%s' on signed value nonportable */ 2288 warning(120, op_name(op)); 2289 } 2290 } else if (allow_trad && allow_c90 && 2291 !is_uinteger(olt) && is_uinteger(ort)) { 2292 /* The left operand would become unsigned in traditional C. */ 2293 if (hflag && (ln->tn_op != CON || ln->tn_val.u.integer < 0)) { 2294 /* semantics of '%s' change in C90; use ... */ 2295 warning(118, op_name(op)); 2296 } 2297 } else if (allow_trad && allow_c90 && 2298 !is_uinteger(olt) && !is_uinteger(ort) && 2299 portable_rank_cmp(lt, rt) < 0) { 2300 /* 2301 * In traditional C, the left operand would be extended 2302 * (possibly sign-extended) and then shifted. 2303 */ 2304 if (hflag && (ln->tn_op != CON || ln->tn_val.u.integer < 0)) { 2305 /* semantics of '%s' change in C90; use ... */ 2306 warning(118, op_name(op)); 2307 } 2308 } 2309 } 2310 2311 static void 2312 typeok_shl(op_t op, tspec_t lt, tspec_t rt) 2313 { 2314 /* 2315 * C90 does not perform balancing for shift operations, 2316 * but traditional C does. If the width of the right operand 2317 * is greater than the width of the left operand, then in 2318 * traditional C the left operand would be extended to the 2319 * width of the right operand. For SHL this may result in 2320 * different results. 2321 */ 2322 if (portable_rank_cmp(lt, rt) < 0) { 2323 /* 2324 * XXX If both operands are constant, make sure 2325 * that there is really a difference between 2326 * C90 and traditional C. 2327 */ 2328 if (hflag && allow_trad && allow_c90) 2329 /* semantics of '%s' change in C90; use ... */ 2330 warning(118, op_name(op)); 2331 } 2332 } 2333 2334 static void 2335 typeok_shift(const type_t *ltp, tspec_t lt, const tnode_t *rn, tspec_t rt) 2336 { 2337 if (rn->tn_op != CON) 2338 return; 2339 2340 if (!is_uinteger(rt) && rn->tn_val.u.integer < 0) { 2341 /* negative shift */ 2342 warning(121); 2343 } else if ((uint64_t)rn->tn_val.u.integer == size_in_bits(lt)) { 2344 /* shift amount %u equals bit-size of '%s' */ 2345 warning(267, (unsigned)rn->tn_val.u.integer, type_name(ltp)); 2346 } else if ((uint64_t)rn->tn_val.u.integer > size_in_bits(lt)) { 2347 /* shift amount %llu is greater than bit-size %llu of '%s' */ 2348 warning(122, (unsigned long long)rn->tn_val.u.integer, 2349 (unsigned long long)size_in_bits(lt), 2350 tspec_name(lt)); 2351 } 2352 } 2353 2354 static bool 2355 is_typeok_eq(const tnode_t *ln, tspec_t lt, const tnode_t *rn, tspec_t rt) 2356 { 2357 if (lt == PTR && is_null_pointer(rn)) 2358 return true; 2359 if (rt == PTR && is_null_pointer(ln)) 2360 return true; 2361 return false; 2362 } 2363 2364 /* 2365 * Called if incompatible pointer types are detected. 2366 * Print an appropriate warning. 2367 */ 2368 static void 2369 warn_incompatible_pointers(op_t op, const type_t *ltp, const type_t *rtp) 2370 { 2371 lint_assert(ltp->t_tspec == PTR); 2372 lint_assert(rtp->t_tspec == PTR); 2373 2374 tspec_t lt = ltp->t_subt->t_tspec; 2375 tspec_t rt = rtp->t_subt->t_tspec; 2376 2377 if (is_struct_or_union(lt) && is_struct_or_union(rt)) { 2378 if (op == RETURN) { 2379 /* illegal structure pointer combination */ 2380 warning(244); 2381 } else { 2382 /* incompatible structure pointers: '%s' '%s' '%s' */ 2383 warning(245, type_name(ltp), 2384 op_name(op), type_name(rtp)); 2385 } 2386 } else { 2387 if (op == RETURN) { 2388 /* illegal combination of '%s' and '%s' */ 2389 warning(184, type_name(ltp), type_name(rtp)); 2390 } else { 2391 /* illegal combination of '%s' and '%s', op '%s' */ 2392 warning(124, 2393 type_name(ltp), type_name(rtp), op_name(op)); 2394 } 2395 } 2396 } 2397 2398 static void 2399 check_pointer_comparison(op_t op, const tnode_t *ln, const tnode_t *rn) 2400 { 2401 type_t *ltp = ln->tn_type, *rtp = rn->tn_type; 2402 tspec_t lst = ltp->t_subt->t_tspec, rst = rtp->t_subt->t_tspec; 2403 2404 if (lst == VOID || rst == VOID) { 2405 /* TODO: C99 behaves like C90 here. */ 2406 if ((!allow_trad && !allow_c99) && 2407 (lst == FUNC || rst == FUNC)) { 2408 /* (void *)0 is already handled in typeok() */ 2409 const char *lsts, *rsts; 2410 *(lst == FUNC ? &lsts : &rsts) = "function pointer"; 2411 *(lst == VOID ? &lsts : &rsts) = "'void *'"; 2412 /* C90 or later forbid comparison of %s with %s */ 2413 warning(274, lsts, rsts); 2414 } 2415 return; 2416 } 2417 2418 if (!types_compatible(ltp->t_subt, rtp->t_subt, true, false, NULL)) { 2419 warn_incompatible_pointers(op, ltp, rtp); 2420 return; 2421 } 2422 2423 if (lst == FUNC && rst == FUNC) { 2424 /* TODO: C99 behaves like C90 here, see C99 6.5.8p2. */ 2425 if ((!allow_trad && !allow_c99) && op != EQ && op != NE) 2426 /* pointers to functions can only be compared ... */ 2427 warning(125); 2428 } 2429 } 2430 2431 static bool 2432 typeok_compare(op_t op, 2433 const tnode_t *ln, const type_t *ltp, tspec_t lt, 2434 const tnode_t *rn, const type_t *rtp, tspec_t rt) 2435 { 2436 if (lt == PTR && rt == PTR) { 2437 check_pointer_comparison(op, ln, rn); 2438 return true; 2439 } 2440 2441 if (lt != PTR && rt != PTR) 2442 return true; 2443 2444 if (!is_integer(lt) && !is_integer(rt)) { 2445 warn_incompatible_types(op, ltp, lt, rtp, rt); 2446 return false; 2447 } 2448 2449 const char *lx = lt == PTR ? "pointer" : "integer"; 2450 const char *rx = rt == PTR ? "pointer" : "integer"; 2451 /* illegal combination of %s '%s' and %s '%s', op '%s' */ 2452 warning(123, lx, type_name(ltp), rx, type_name(rtp), op_name(op)); 2453 return true; 2454 } 2455 2456 static bool 2457 typeok_quest(tspec_t lt, const tnode_t *rn) 2458 { 2459 if (!is_scalar(lt)) { 2460 /* first operand of '?' must have scalar type */ 2461 error(170); 2462 return false; 2463 } 2464 lint_assert(before_conversion(rn)->tn_op == COLON); 2465 return true; 2466 } 2467 2468 static void 2469 typeok_colon_pointer(const type_t *ltp, const type_t *rtp) 2470 { 2471 type_t *lstp = ltp->t_subt; 2472 type_t *rstp = rtp->t_subt; 2473 tspec_t lst = lstp->t_tspec; 2474 tspec_t rst = rstp->t_tspec; 2475 2476 if ((lst == VOID && rst == FUNC) || (lst == FUNC && rst == VOID)) { 2477 /* (void *)0 is handled in typeok_colon */ 2478 /* TODO: C99 behaves like C90 here. */ 2479 if (!allow_trad && !allow_c99) 2480 /* conversion of %s to %s requires a cast, op %s */ 2481 warning(305, "function pointer", "'void *'", 2482 op_name(COLON)); 2483 return; 2484 } 2485 2486 if (pointer_types_are_compatible(lstp, rstp, true)) 2487 return; 2488 if (!types_compatible(lstp, rstp, true, false, NULL)) 2489 warn_incompatible_pointers(COLON, ltp, rtp); 2490 } 2491 2492 static bool 2493 typeok_colon(const tnode_t *ln, const type_t *ltp, tspec_t lt, 2494 const tnode_t *rn, const type_t *rtp, tspec_t rt) 2495 { 2496 2497 if (is_arithmetic(lt) && is_arithmetic(rt)) 2498 return true; 2499 if (lt == BOOL && rt == BOOL) 2500 return true; 2501 2502 if (lt == STRUCT && rt == STRUCT && ltp->t_sou == rtp->t_sou) 2503 return true; 2504 if (lt == UNION && rt == UNION && ltp->t_sou == rtp->t_sou) 2505 return true; 2506 2507 if (lt == PTR && is_null_pointer(rn)) 2508 return true; 2509 if (rt == PTR && is_null_pointer(ln)) 2510 return true; 2511 2512 if ((lt == PTR && is_integer(rt)) || (is_integer(lt) && rt == PTR)) { 2513 const char *lx = lt == PTR ? "pointer" : "integer"; 2514 const char *rx = rt == PTR ? "pointer" : "integer"; 2515 /* illegal combination of %s '%s' and %s '%s', op '%s' */ 2516 warning(123, lx, type_name(ltp), 2517 rx, type_name(rtp), op_name(COLON)); 2518 return true; 2519 } 2520 2521 if (lt == VOID || rt == VOID) { 2522 if (lt != VOID || rt != VOID) 2523 /* incompatible types '%s' and '%s' in conditional */ 2524 warning(126, type_name(ltp), type_name(rtp)); 2525 return true; 2526 } 2527 2528 if (lt == PTR && rt == PTR) { 2529 typeok_colon_pointer(ltp, rtp); 2530 return true; 2531 } 2532 2533 /* incompatible types '%s' and '%s' in conditional */ 2534 error(126, type_name(ltp), type_name(rtp)); 2535 return false; 2536 } 2537 2538 /* 2539 * Returns true if the given structure or union has a constant member 2540 * (maybe recursively). 2541 */ 2542 static bool 2543 has_constant_member(const type_t *tp) 2544 { 2545 lint_assert(is_struct_or_union(tp->t_tspec)); 2546 2547 for (sym_t *m = tp->t_sou->sou_first_member; 2548 m != NULL; m = m->s_next) { 2549 const type_t *mtp = m->s_type; 2550 if (mtp->t_const) 2551 return true; 2552 if (is_struct_or_union(mtp->t_tspec) && 2553 has_constant_member(mtp)) 2554 return true; 2555 } 2556 return false; 2557 } 2558 2559 static bool 2560 typeok_assign(op_t op, const tnode_t *ln, const type_t *ltp, tspec_t lt) 2561 { 2562 if (op == RETURN || op == INIT || op == FARG) 2563 return true; 2564 2565 if (!ln->tn_lvalue) { 2566 if (ln->tn_op == CVT && ln->tn_cast && 2567 ln->tn_left->tn_op == LOAD) { 2568 /* a cast does not yield an lvalue */ 2569 error(163); 2570 } 2571 /* %soperand of '%s' must be lvalue */ 2572 error(114, "left ", op_name(op)); 2573 return false; 2574 } else if (ltp->t_const 2575 || (is_struct_or_union(lt) && has_constant_member(ltp))) { 2576 if (allow_c90) 2577 /* %soperand of '%s' must be modifiable lvalue */ 2578 warning(115, "left ", op_name(op)); 2579 } 2580 return true; 2581 } 2582 2583 /* Check the types using the information from modtab[]. */ 2584 static bool 2585 typeok_scalar(op_t op, const mod_t *mp, 2586 const type_t *ltp, tspec_t lt, 2587 const type_t *rtp, tspec_t rt) 2588 { 2589 if (mp->m_takes_bool && lt == BOOL && rt == BOOL) 2590 return true; 2591 if (mp->m_requires_integer) { 2592 if (!is_integer(lt) || (mp->m_binary && !is_integer(rt))) { 2593 warn_incompatible_types(op, ltp, lt, rtp, rt); 2594 return false; 2595 } 2596 } else if (mp->m_requires_integer_or_complex) { 2597 if ((!is_integer(lt) && !is_complex(lt)) || 2598 (mp->m_binary && (!is_integer(rt) && !is_complex(rt)))) { 2599 warn_incompatible_types(op, ltp, lt, rtp, rt); 2600 return false; 2601 } 2602 } else if (mp->m_requires_scalar) { 2603 if (!is_scalar(lt) || (mp->m_binary && !is_scalar(rt))) { 2604 warn_incompatible_types(op, ltp, lt, rtp, rt); 2605 return false; 2606 } 2607 } else if (mp->m_requires_arith) { 2608 if (!is_arithmetic(lt) || 2609 (mp->m_binary && !is_arithmetic(rt))) { 2610 warn_incompatible_types(op, ltp, lt, rtp, rt); 2611 return false; 2612 } 2613 } 2614 return true; 2615 } 2616 2617 static void 2618 check_assign_void_pointer(op_t op, int arg, 2619 tspec_t lt, tspec_t lst, 2620 tspec_t rt, tspec_t rst) 2621 { 2622 2623 if (!(lt == PTR && rt == PTR && (lst == VOID || rst == VOID))) 2624 return; 2625 /* two pointers, at least one pointer to void */ 2626 2627 /* TODO: C99 behaves like C90 here. */ 2628 if (!((!allow_trad && !allow_c99) && (lst == FUNC || rst == FUNC))) 2629 return; 2630 /* comb. of ptr to func and ptr to void */ 2631 2632 const char *lts, *rts; 2633 *(lst == FUNC ? <s : &rts) = "function pointer"; 2634 *(lst == VOID ? <s : &rts) = "'void *'"; 2635 2636 switch (op) { 2637 case INIT: 2638 case RETURN: 2639 /* conversion of %s to %s requires a cast */ 2640 warning(303, rts, lts); 2641 break; 2642 case FARG: 2643 /* conversion of %s to %s requires a cast, arg #%d */ 2644 warning(304, rts, lts, arg); 2645 break; 2646 default: 2647 /* conversion of %s to %s requires a cast, op %s */ 2648 warning(305, rts, lts, op_name(op)); 2649 break; 2650 } 2651 } 2652 2653 static bool 2654 is_direct_function_call(const tnode_t *tn, const char **out_name) 2655 { 2656 2657 if (!(tn->tn_op == CALL && 2658 tn->tn_left->tn_op == ADDR && 2659 tn->tn_left->tn_left->tn_op == NAME)) 2660 return false; 2661 2662 *out_name = tn->tn_left->tn_left->tn_sym->s_name; 2663 return true; 2664 } 2665 2666 static bool 2667 is_unconst_function(const char *name) 2668 { 2669 2670 return strcmp(name, "memchr") == 0 || 2671 strcmp(name, "strchr") == 0 || 2672 strcmp(name, "strpbrk") == 0 || 2673 strcmp(name, "strrchr") == 0 || 2674 strcmp(name, "strstr") == 0; 2675 } 2676 2677 static bool 2678 is_const_char_pointer(const tnode_t *tn) 2679 { 2680 /* 2681 * For traditional reasons, C99 6.4.5p5 defines that string literals 2682 * have type 'char[]'. They are often implicitly converted to 2683 * 'char *', for example when they are passed as function arguments. 2684 * 2685 * C99 6.4.5p6 further defines that modifying a string that is 2686 * constructed from a string literal invokes undefined behavior. 2687 * 2688 * Out of these reasons, string literals are treated as 'effectively 2689 * const' here. 2690 */ 2691 if (tn->tn_op == CVT && 2692 tn->tn_left->tn_op == ADDR && 2693 tn->tn_left->tn_left->tn_op == STRING) 2694 return true; 2695 2696 const type_t *tp = before_conversion(tn)->tn_type; 2697 return tp->t_tspec == PTR && 2698 tp->t_subt->t_tspec == CHAR && 2699 tp->t_subt->t_const; 2700 } 2701 2702 static bool 2703 is_first_arg_const_char_pointer(const tnode_t *tn) 2704 { 2705 const tnode_t *an = tn->tn_right; 2706 if (an == NULL) 2707 return false; 2708 2709 while (an->tn_right != NULL) 2710 an = an->tn_right; 2711 return is_const_char_pointer(an->tn_left); 2712 } 2713 2714 static bool 2715 is_const_pointer(const tnode_t *tn) 2716 { 2717 const type_t *tp = before_conversion(tn)->tn_type; 2718 return tp->t_tspec == PTR && tp->t_subt->t_const; 2719 } 2720 2721 static bool 2722 is_second_arg_const_pointer(const tnode_t *tn) 2723 { 2724 const tnode_t *an = tn->tn_right; 2725 if (an == NULL || an->tn_right == NULL) 2726 return false; 2727 2728 while (an->tn_right->tn_right != NULL) 2729 an = an->tn_right; 2730 return is_const_pointer(an->tn_left); 2731 } 2732 2733 static void 2734 check_unconst_function(const type_t *lstp, const tnode_t *rn) 2735 { 2736 const char *function_name; 2737 2738 if (lstp->t_tspec == CHAR && !lstp->t_const && 2739 is_direct_function_call(rn, &function_name) && 2740 is_unconst_function(function_name) && 2741 is_first_arg_const_char_pointer(rn)) { 2742 /* call to '%s' effectively discards 'const' from argument */ 2743 warning(346, function_name); 2744 } 2745 2746 if (!lstp->t_const && 2747 is_direct_function_call(rn, &function_name) && 2748 strcmp(function_name, "bsearch") == 0 && 2749 is_second_arg_const_pointer(rn)) { 2750 /* call to '%s' effectively discards 'const' from argument */ 2751 warning(346, function_name); 2752 } 2753 } 2754 2755 static bool 2756 check_assign_void_pointer_compat(op_t op, int arg, 2757 const type_t *const ltp, tspec_t const lt, 2758 const type_t *const lstp, tspec_t const lst, 2759 const tnode_t *const rn, 2760 const type_t *const rtp, tspec_t const rt, 2761 const type_t *const rstp, tspec_t const rst) 2762 { 2763 if (!(lt == PTR && rt == PTR && (lst == VOID || rst == VOID || 2764 types_compatible(lstp, rstp, 2765 true, false, NULL)))) 2766 return false; 2767 2768 /* compatible pointer types (qualifiers ignored) */ 2769 if (allow_c90 && 2770 ((!lstp->t_const && rstp->t_const) || 2771 (!lstp->t_volatile && rstp->t_volatile))) { 2772 /* left side has not all qualifiers of right */ 2773 switch (op) { 2774 case INIT: 2775 case RETURN: 2776 /* incompatible pointer types to '%s' and '%s' */ 2777 warning(182, type_name(lstp), type_name(rstp)); 2778 break; 2779 case FARG: 2780 /* converting '%s' to incompatible '%s' ... */ 2781 warning(153, 2782 type_name(rtp), type_name(ltp), arg); 2783 break; 2784 default: 2785 /* operands of '%s' have incompatible pointer ... */ 2786 warning(128, op_name(op), 2787 type_name(lstp), type_name(rstp)); 2788 break; 2789 } 2790 } 2791 2792 if (allow_c90) 2793 check_unconst_function(lstp, rn); 2794 2795 return true; 2796 } 2797 2798 static bool 2799 check_assign_pointer_integer(op_t op, int arg, 2800 const type_t *const ltp, tspec_t const lt, 2801 const type_t *const rtp, tspec_t const rt) 2802 { 2803 2804 if (!((lt == PTR && is_integer(rt)) || (is_integer(lt) && rt == PTR))) 2805 return false; 2806 2807 const char *lx = lt == PTR ? "pointer" : "integer"; 2808 const char *rx = rt == PTR ? "pointer" : "integer"; 2809 2810 switch (op) { 2811 case INIT: 2812 case RETURN: 2813 /* illegal combination of %s '%s' and %s '%s' */ 2814 warning(183, lx, type_name(ltp), rx, type_name(rtp)); 2815 break; 2816 case FARG: 2817 /* illegal combination of %s '%s' and %s '%s', arg #%d */ 2818 warning(154, 2819 lx, type_name(ltp), rx, type_name(rtp), arg); 2820 break; 2821 default: 2822 /* illegal combination of %s '%s' and %s '%s', op '%s' */ 2823 warning(123, 2824 lx, type_name(ltp), rx, type_name(rtp), op_name(op)); 2825 break; 2826 } 2827 return true; 2828 } 2829 2830 static bool 2831 check_assign_pointer(op_t op, int arg, 2832 const type_t *ltp, tspec_t lt, 2833 const type_t *rtp, tspec_t rt) 2834 { 2835 if (!(lt == PTR && rt == PTR)) 2836 return false; 2837 2838 if (op == FARG) 2839 /* converting '%s' to incompatible '%s' for ... */ 2840 warning(153, type_name(rtp), type_name(ltp), arg); 2841 else 2842 warn_incompatible_pointers(op, ltp, rtp); 2843 return true; 2844 } 2845 2846 static void 2847 warn_assign(op_t op, int arg, 2848 const type_t *ltp, tspec_t lt, 2849 const type_t *rtp, tspec_t rt) 2850 { 2851 switch (op) { 2852 case INIT: 2853 /* cannot initialize '%s' from '%s' */ 2854 error(185, type_name(ltp), type_name(rtp)); 2855 break; 2856 case RETURN: 2857 /* function has return type '%s' but returns '%s' */ 2858 error(211, type_name(ltp), type_name(rtp)); 2859 break; 2860 case FARG: 2861 /* passing '%s' to incompatible '%s', arg #%d */ 2862 warning(155, type_name(rtp), type_name(ltp), arg); 2863 break; 2864 default: 2865 warn_incompatible_types(op, ltp, lt, rtp, rt); 2866 break; 2867 } 2868 } 2869 2870 /* 2871 * Checks type compatibility for ASSIGN, INIT, FARG and RETURN 2872 * and prints warnings/errors if necessary. 2873 * Returns whether the types are (almost) compatible. 2874 */ 2875 static bool 2876 check_assign_types_compatible(op_t op, int arg, 2877 const tnode_t *ln, const tnode_t *rn) 2878 { 2879 tspec_t lt, rt, lst = NO_TSPEC, rst = NO_TSPEC; 2880 type_t *ltp, *rtp, *lstp = NULL, *rstp = NULL; 2881 2882 if ((lt = (ltp = ln->tn_type)->t_tspec) == PTR) 2883 lst = (lstp = ltp->t_subt)->t_tspec; 2884 if ((rt = (rtp = rn->tn_type)->t_tspec) == PTR) 2885 rst = (rstp = rtp->t_subt)->t_tspec; 2886 2887 if (lt == BOOL && is_scalar(rt)) /* C99 6.3.1.2 */ 2888 return true; 2889 2890 if (is_arithmetic(lt) && (is_arithmetic(rt) || rt == BOOL)) 2891 return true; 2892 2893 if (is_struct_or_union(lt) && is_struct_or_union(rt)) 2894 /* both are struct or union */ 2895 return ltp->t_sou == rtp->t_sou; 2896 2897 /* a null pointer may be assigned to any pointer */ 2898 if (lt == PTR && is_null_pointer(rn)) { 2899 if (is_integer(rn->tn_type->t_tspec)) 2900 /* implicit conversion from integer 0 to pointer ... */ 2901 query_message(15, type_name(ltp)); 2902 return true; 2903 } 2904 2905 check_assign_void_pointer(op, arg, lt, lst, rt, rst); 2906 2907 if (check_assign_void_pointer_compat(op, arg, 2908 ltp, lt, lstp, lst, rn, rtp, rt, rstp, rst)) 2909 return true; 2910 2911 if (check_assign_pointer_integer(op, arg, ltp, lt, rtp, rt)) 2912 return true; 2913 2914 if (check_assign_pointer(op, arg, ltp, lt, rtp, rt)) 2915 return true; 2916 2917 warn_assign(op, arg, ltp, lt, rtp, rt); 2918 return false; 2919 } 2920 2921 static bool 2922 has_side_effect(const tnode_t *tn) /* NOLINT(misc-no-recursion) */ 2923 { 2924 op_t op = tn->tn_op; 2925 2926 if (modtab[op].m_has_side_effect) 2927 return true; 2928 2929 if (op == CVT && tn->tn_type->t_tspec == VOID) 2930 return has_side_effect(tn->tn_left); 2931 2932 /* XXX: Why not has_side_effect(tn->tn_left) as well? */ 2933 if (op == LOGAND || op == LOGOR) 2934 return has_side_effect(tn->tn_right); 2935 2936 /* XXX: Why not has_side_effect(tn->tn_left) as well? */ 2937 if (op == QUEST) 2938 return has_side_effect(tn->tn_right); 2939 2940 if (op == COLON || op == COMMA) { 2941 return has_side_effect(tn->tn_left) || 2942 has_side_effect(tn->tn_right); 2943 } 2944 2945 return false; 2946 } 2947 2948 static bool 2949 is_void_cast(const tnode_t *tn) 2950 { 2951 2952 return tn->tn_op == CVT && tn->tn_cast && 2953 tn->tn_type->t_tspec == VOID; 2954 } 2955 2956 static bool 2957 is_local_symbol(const tnode_t *tn) 2958 { 2959 2960 return tn->tn_op == LOAD && 2961 tn->tn_left->tn_op == NAME && 2962 tn->tn_left->tn_sym->s_scl == AUTO; 2963 } 2964 2965 static bool 2966 is_int_constant_zero(const tnode_t *tn) 2967 { 2968 2969 return tn->tn_op == CON && 2970 tn->tn_type->t_tspec == INT && 2971 tn->tn_val.u.integer == 0; 2972 } 2973 2974 static void 2975 check_null_effect(const tnode_t *tn) 2976 { 2977 2978 if (hflag && 2979 !has_side_effect(tn) && 2980 !(is_void_cast(tn) && is_local_symbol(tn->tn_left)) && 2981 !(is_void_cast(tn) && is_int_constant_zero(tn->tn_left))) { 2982 /* expression has null effect */ 2983 warning(129); 2984 } 2985 } 2986 2987 /* 2988 * Check the types for specific operators and type combinations. 2989 * 2990 * At this point, the operands already conform to the type requirements of 2991 * the operator, such as being integer, floating or scalar. 2992 */ 2993 static bool 2994 typeok_op(op_t op, int arg, 2995 const tnode_t *ln, const type_t *ltp, tspec_t lt, 2996 const tnode_t *rn, const type_t *rtp, tspec_t rt) 2997 { 2998 switch (op) { 2999 case ARROW: 3000 return typeok_arrow(lt); 3001 case POINT: 3002 return typeok_point(ln, ltp, lt); 3003 case INCBEF: 3004 case DECBEF: 3005 case INCAFT: 3006 case DECAFT: 3007 return typeok_incdec(op, ln, ltp); 3008 case INDIR: 3009 return typeok_indir(ltp, lt); 3010 case ADDR: 3011 return typeok_address(op, ln, ltp, lt); 3012 case PLUS: 3013 return typeok_plus(op, ltp, lt, rtp, rt); 3014 case MINUS: 3015 return typeok_minus(op, ltp, lt, rtp, rt); 3016 case SHL: 3017 typeok_shl(op, lt, rt); 3018 goto shift; 3019 case SHR: 3020 typeok_shr(op, ln, lt, rn, rt); 3021 shift: 3022 typeok_shift(ltp, lt, rn, rt); 3023 break; 3024 case LT: 3025 case LE: 3026 case GT: 3027 case GE: 3028 compare: 3029 return typeok_compare(op, ln, ltp, lt, rn, rtp, rt); 3030 case EQ: 3031 case NE: 3032 if (is_typeok_eq(ln, lt, rn, rt)) 3033 break; 3034 goto compare; 3035 case QUEST: 3036 return typeok_quest(lt, rn); 3037 case COLON: 3038 return typeok_colon(ln, ltp, lt, rn, rtp, rt); 3039 case ASSIGN: 3040 case INIT: 3041 case FARG: 3042 case RETURN: 3043 if (!check_assign_types_compatible(op, arg, ln, rn)) 3044 return false; 3045 goto assign; 3046 case MULASS: 3047 case DIVASS: 3048 case MODASS: 3049 goto assign; 3050 case ADDASS: 3051 case SUBASS: 3052 if ((lt == PTR && !is_integer(rt)) || rt == PTR) { 3053 warn_incompatible_types(op, ltp, lt, rtp, rt); 3054 return false; 3055 } 3056 goto assign; 3057 case SHLASS: 3058 goto assign; 3059 case SHRASS: 3060 if (pflag && !is_uinteger(lt) && 3061 !(!allow_c90 && is_uinteger(rt))) { 3062 /* bitwise '%s' on signed value possibly nonportable */ 3063 warning(117, op_name(op)); 3064 } 3065 goto assign; 3066 case ANDASS: 3067 case XORASS: 3068 case ORASS: 3069 assign: 3070 return typeok_assign(op, ln, ltp, lt); 3071 case COMMA: 3072 if (!modtab[ln->tn_op].m_has_side_effect) 3073 check_null_effect(ln); 3074 break; 3075 default: 3076 break; 3077 } 3078 return true; 3079 } 3080 3081 /* Prints a warning if a strange operator is used on an enum type. */ 3082 static void 3083 check_bad_enum_operation(op_t op, const tnode_t *ln, const tnode_t *rn) 3084 { 3085 3086 if (!eflag) 3087 return; 3088 3089 /* Allow enum in array indices. */ 3090 if (op == PLUS && 3091 ((ln->tn_type->t_is_enum && rn->tn_type->t_tspec == PTR) || 3092 (rn->tn_type->t_is_enum && ln->tn_type->t_tspec == PTR))) { 3093 return; 3094 } 3095 3096 /* dubious operation '%s' on enum */ 3097 warning(241, op_name(op)); 3098 } 3099 3100 /* Prints a warning if an operator is applied to two different enum types. */ 3101 static void 3102 check_enum_type_mismatch(op_t op, int arg, const tnode_t *ln, const tnode_t *rn) 3103 { 3104 const mod_t *mp = &modtab[op]; 3105 3106 if (ln->tn_type->t_enum != rn->tn_type->t_enum) { 3107 switch (op) { 3108 case INIT: 3109 /* enum type mismatch between '%s' and '%s' in ... */ 3110 warning(210, 3111 type_name(ln->tn_type), type_name(rn->tn_type)); 3112 break; 3113 case FARG: 3114 /* function expects '%s', passing '%s' for arg #%d */ 3115 warning(156, 3116 type_name(ln->tn_type), type_name(rn->tn_type), 3117 arg); 3118 break; 3119 case RETURN: 3120 /* function has return type '%s' but returns '%s' */ 3121 warning(211, 3122 type_name(ln->tn_type), type_name(rn->tn_type)); 3123 break; 3124 default: 3125 /* enum type mismatch: '%s' '%s' '%s' */ 3126 warning(130, type_name(ln->tn_type), op_name(op), 3127 type_name(rn->tn_type)); 3128 break; 3129 } 3130 } else if (Pflag && eflag && mp->m_comparison && op != EQ && op != NE) 3131 /* operator '%s' assumes that '%s' is ordered */ 3132 warning(243, op_name(op), type_name(ln->tn_type)); 3133 } 3134 3135 /* Prints a warning if the operands mix between enum and integer. */ 3136 static void 3137 check_enum_int_mismatch(op_t op, int arg, const tnode_t *ln, const tnode_t *rn) 3138 { 3139 3140 if (!eflag) 3141 return; 3142 3143 switch (op) { 3144 case INIT: 3145 /* 3146 * Initialization with 0 is allowed. Otherwise, all implicit 3147 * initializations would need to be warned upon as well. 3148 */ 3149 if (!rn->tn_type->t_is_enum && rn->tn_op == CON && 3150 is_integer(rn->tn_type->t_tspec) && 3151 rn->tn_val.u.integer == 0) { 3152 return; 3153 } 3154 /* initialization of '%s' with '%s' */ 3155 warning(277, type_name(ln->tn_type), type_name(rn->tn_type)); 3156 break; 3157 case FARG: 3158 /* combination of '%s' and '%s', arg #%d */ 3159 warning(278, 3160 type_name(ln->tn_type), type_name(rn->tn_type), arg); 3161 break; 3162 case RETURN: 3163 /* combination of '%s' and '%s' in return */ 3164 warning(279, type_name(ln->tn_type), type_name(rn->tn_type)); 3165 break; 3166 default: 3167 /* combination of '%s' and '%s', op '%s' */ 3168 warning(242, type_name(ln->tn_type), type_name(rn->tn_type), 3169 op_name(op)); 3170 break; 3171 } 3172 } 3173 3174 static void 3175 typeok_enum(op_t op, const mod_t *mp, int arg, 3176 const tnode_t *ln, const type_t *ltp, 3177 const tnode_t *rn, const type_t *rtp) 3178 { 3179 if (mp->m_bad_on_enum && 3180 (ltp->t_is_enum || (mp->m_binary && rtp->t_is_enum))) { 3181 check_bad_enum_operation(op, ln, rn); 3182 } else if (mp->m_valid_on_enum && 3183 (ltp->t_is_enum && rtp != NULL && rtp->t_is_enum)) { 3184 check_enum_type_mismatch(op, arg, ln, rn); 3185 } else if (mp->m_valid_on_enum && 3186 (ltp->t_is_enum || (rtp != NULL && rtp->t_is_enum))) { 3187 check_enum_int_mismatch(op, arg, ln, rn); 3188 } 3189 } 3190 3191 /* Perform most type checks. Return whether the types are ok. */ 3192 bool 3193 typeok(op_t op, int arg, const tnode_t *ln, const tnode_t *rn) 3194 { 3195 3196 const mod_t *mp = &modtab[op]; 3197 3198 type_t *ltp = ln->tn_type; 3199 tspec_t lt = ltp->t_tspec; 3200 3201 type_t *rtp = mp->m_binary ? rn->tn_type : NULL; 3202 tspec_t rt = mp->m_binary ? rtp->t_tspec : NO_TSPEC; 3203 3204 if (Tflag && !typeok_scalar_strict_bool(op, mp, arg, ln, rn)) 3205 return false; 3206 if (!typeok_scalar(op, mp, ltp, lt, rtp, rt)) 3207 return false; 3208 3209 if (!typeok_op(op, arg, ln, ltp, lt, rn, rtp, rt)) 3210 return false; 3211 3212 typeok_enum(op, mp, arg, ln, ltp, rn, rtp); 3213 return true; 3214 } 3215 3216 /* In traditional C, keep unsigned and promote FLOAT to DOUBLE. */ 3217 static tspec_t 3218 promote_trad(tspec_t t) 3219 { 3220 3221 if (t == UCHAR || t == USHORT) 3222 return UINT; 3223 if (t == CHAR || t == SCHAR || t == SHORT) 3224 return INT; 3225 if (t == FLOAT) 3226 return DOUBLE; 3227 if (t == ENUM) 3228 return INT; 3229 return t; 3230 } 3231 3232 /* 3233 * C99 6.3.1.1p2 requires for types with lower rank than int that "If an int 3234 * can represent all the values of the original type, the value is converted 3235 * to an int; otherwise it is converted to an unsigned int", and that "All 3236 * other types are unchanged by the integer promotions". 3237 */ 3238 static tspec_t 3239 promote_c90(const tnode_t *tn, tspec_t t, bool farg) 3240 { 3241 if (tn->tn_type->t_bitfield) { 3242 unsigned int width = tn->tn_type->t_bit_field_width; 3243 unsigned int int_width = size_in_bits(INT); 3244 // XXX: What about _Bool bit-fields, since C99? 3245 if (width < int_width) 3246 return INT; 3247 if (width == int_width) 3248 return is_uinteger(t) ? UINT : INT; 3249 return t; 3250 } 3251 3252 if (t == CHAR || t == SCHAR) 3253 return INT; 3254 if (t == UCHAR) 3255 return size_in_bits(CHAR) < size_in_bits(INT) ? INT : UINT; 3256 if (t == SHORT) 3257 return INT; 3258 if (t == USHORT) 3259 return size_in_bits(SHORT) < size_in_bits(INT) ? INT : UINT; 3260 if (t == ENUM) 3261 return INT; 3262 if (farg && t == FLOAT) 3263 return DOUBLE; 3264 return t; 3265 } 3266 3267 /* 3268 * Performs the "integer promotions" (C99 6.3.1.1p2), which convert small 3269 * integer types to either int or unsigned int. 3270 * 3271 * If allow_c90 is unset or the operand is a function argument with no type 3272 * information (no prototype or variable # of args), converts float to double. 3273 */ 3274 tnode_t * 3275 promote(op_t op, bool farg, tnode_t *tn) 3276 { 3277 3278 tspec_t ot = tn->tn_type->t_tspec; 3279 if (!is_arithmetic(ot)) 3280 return tn; 3281 3282 tspec_t nt = allow_c90 ? promote_c90(tn, ot, farg) : promote_trad(ot); 3283 if (nt == ot) 3284 return tn; 3285 3286 type_t *ntp = expr_dup_type(tn->tn_type); 3287 ntp->t_tspec = nt; 3288 /* 3289 * Keep t_is_enum even though t_tspec gets converted from 3290 * ENUM to INT, so we are later able to check compatibility 3291 * of enum types. 3292 */ 3293 return convert(op, 0, ntp, tn); 3294 } 3295 3296 static void 3297 convert_integer_from_floating(op_t op, const type_t *tp, const tnode_t *tn) 3298 { 3299 3300 if (op == CVT) 3301 /* cast from floating point '%s' to integer '%s' */ 3302 query_message(2, type_name(tn->tn_type), type_name(tp)); 3303 else 3304 /* implicit conversion from floating point '%s' to ... */ 3305 query_message(1, type_name(tn->tn_type), type_name(tp)); 3306 } 3307 3308 static bool 3309 should_warn_about_prototype_conversion(tspec_t nt, 3310 tspec_t ot, const tnode_t *ptn) 3311 { 3312 3313 if (nt == ot) 3314 return false; 3315 3316 if (nt == ENUM && ot == INT) 3317 return false; 3318 3319 if (is_floating(nt) != is_floating(ot) || 3320 portable_rank_cmp(nt, ot) != 0) { 3321 /* representation and/or width change */ 3322 if (!is_integer(ot)) 3323 return true; 3324 /* 3325 * XXX: Investigate whether this rule makes sense; see 3326 * tests/usr.bin/xlint/lint1/platform_long.c. 3327 */ 3328 return portable_rank_cmp(ot, INT) > 0; 3329 } 3330 3331 if (!hflag) 3332 return false; 3333 3334 /* 3335 * If the types differ only in sign and the argument has the same 3336 * representation in both types, print no warning. 3337 */ 3338 if (ptn->tn_op == CON && is_integer(nt) && 3339 signed_type(nt) == signed_type(ot) && 3340 !msb(ptn->tn_val.u.integer, ot)) 3341 return false; 3342 3343 return true; 3344 } 3345 3346 /* 3347 * Warn if a prototype causes a type conversion that is different from what 3348 * would happen to the same argument in the absence of a prototype. This 3349 * check is intended for code that needs to stay compatible with pre-C90 C. 3350 * 3351 * Errors/warnings about illegal type combinations are already printed 3352 * in check_assign_types_compatible(). 3353 */ 3354 static void 3355 check_prototype_conversion(int arg, tspec_t nt, tspec_t ot, type_t *tp, 3356 tnode_t *tn) 3357 { 3358 3359 if (!is_arithmetic(nt) || !is_arithmetic(ot)) 3360 return; 3361 3362 /* 3363 * If the type of the formal parameter is char/short, a warning 3364 * would be useless, because functions declared the old style 3365 * can't expect char/short arguments. 3366 */ 3367 if (nt == CHAR || nt == SCHAR || nt == UCHAR || 3368 nt == SHORT || nt == USHORT) 3369 return; 3370 3371 /* apply the default promotion */ 3372 tnode_t *ptn = promote(NOOP, true, tn); 3373 ot = ptn->tn_type->t_tspec; 3374 3375 if (should_warn_about_prototype_conversion(nt, ot, ptn)) { 3376 /* argument %d is converted from '%s' to '%s' ... */ 3377 warning(259, arg, type_name(tn->tn_type), type_name(tp)); 3378 } 3379 } 3380 3381 /* 3382 * When converting a large integer type to a small integer type, in some 3383 * cases the value of the actual expression is further restricted than the 3384 * type bounds, such as in (expr & 0xFF) or (expr % 100) or (expr >> 24). 3385 */ 3386 static bool 3387 can_represent(const type_t *tp, const tnode_t *tn) 3388 { 3389 3390 debug_step("%s: type '%s'", __func__, type_name(tp)); 3391 debug_node(tn); 3392 3393 uint64_t nmask = value_bits(width_in_bits(tp)); 3394 if (!is_uinteger(tp->t_tspec)) 3395 nmask >>= 1; 3396 3397 integer_constraints c = ic_expr(tn); 3398 if ((~c.bclr & ~nmask) == 0) 3399 return true; 3400 3401 integer_constraints tpc = ic_any(tp); 3402 if (is_uinteger(tp->t_tspec) 3403 ? tpc.umin <= c.umin && tpc.umax >= c.umax 3404 : tpc.smin <= c.smin && tpc.smax >= c.smax) 3405 return true; 3406 3407 return false; 3408 } 3409 3410 static bool 3411 should_warn_about_integer_conversion(const type_t *ntp, tspec_t nt, 3412 const tnode_t *otn, tspec_t ot) 3413 { 3414 3415 // XXX: The portable_rank_cmp aims at portable mode, independent of the 3416 // current platform, while can_represent acts on the actual type sizes 3417 // from the current platform. This mix is inconsistent, but anything 3418 // else would make the exact conditions too complicated to grasp. 3419 if (aflag > 0 && portable_rank_cmp(nt, ot) < 0) { 3420 if (ot == LONG || ot == ULONG 3421 || ot == LLONG || ot == ULLONG 3422 #ifdef INT128_SIZE 3423 || ot == INT128 || ot == UINT128 3424 #endif 3425 || aflag > 1) 3426 return !can_represent(ntp, otn); 3427 } 3428 return false; 3429 } 3430 3431 static void 3432 convert_integer_from_integer(op_t op, int arg, tspec_t nt, tspec_t ot, 3433 type_t *tp, tnode_t *tn) 3434 { 3435 3436 if (tn->tn_op == CON) 3437 return; 3438 3439 if (op == CVT) 3440 return; 3441 3442 if (Pflag && pflag && aflag > 0 && 3443 portable_rank_cmp(nt, ot) > 0 && 3444 is_uinteger(nt) != is_uinteger(ot)) { 3445 if (op == FARG) { 3446 /* conversion to '%s' may sign-extend ... */ 3447 warning(297, type_name(tp), arg); 3448 } else { 3449 /* conversion to '%s' may sign-extend ... */ 3450 warning(131, type_name(tp)); 3451 } 3452 } 3453 3454 if (Pflag && portable_rank_cmp(nt, ot) > 0 && 3455 (tn->tn_op == PLUS || tn->tn_op == MINUS || tn->tn_op == MULT || 3456 tn->tn_op == SHL)) { 3457 /* suggest cast from '%s' to '%s' on op '%s' to ... */ 3458 warning(324, type_name(gettyp(ot)), type_name(tp), 3459 op_name(tn->tn_op)); 3460 } 3461 3462 if (should_warn_about_integer_conversion(tp, nt, tn, ot)) { 3463 if (op == FARG) { 3464 /* conversion from '%s' to '%s' may lose ... */ 3465 warning(298, 3466 type_name(tn->tn_type), type_name(tp), arg); 3467 } else { 3468 /* conversion from '%s' to '%s' may lose accuracy */ 3469 warning(132, 3470 type_name(tn->tn_type), type_name(tp)); 3471 } 3472 } 3473 3474 if (any_query_enabled && is_uinteger(nt) != is_uinteger(ot)) 3475 /* implicit conversion changes sign from '%s' to '%s' */ 3476 query_message(3, type_name(tn->tn_type), type_name(tp)); 3477 } 3478 3479 static void 3480 convert_integer_from_pointer(op_t op, tspec_t nt, type_t *tp, tnode_t *tn) 3481 { 3482 3483 if (tn->tn_op == CON) 3484 return; 3485 if (op != CVT) 3486 return; /* We already got an error. */ 3487 if (portable_rank_cmp(nt, PTR) >= 0) 3488 return; 3489 3490 if (pflag && size_in_bits(nt) >= size_in_bits(PTR)) { 3491 /* conversion of pointer to '%s' may lose bits */ 3492 warning(134, type_name(tp)); 3493 } else { 3494 /* conversion of pointer to '%s' loses bits */ 3495 warning(133, type_name(tp)); 3496 } 3497 } 3498 3499 static bool 3500 struct_starts_with(const type_t *struct_tp, const type_t *member_tp) 3501 { 3502 3503 return struct_tp->t_sou->sou_first_member != NULL && 3504 types_compatible(struct_tp->t_sou->sou_first_member->s_type, 3505 member_tp, true, false, NULL); 3506 } 3507 3508 static bool 3509 is_byte_array(const type_t *tp) 3510 { 3511 3512 return tp->t_tspec == ARRAY && 3513 (tp->t_subt->t_tspec == CHAR || tp->t_subt->t_tspec == UCHAR); 3514 } 3515 3516 static bool 3517 union_contains(const type_t *utp, const type_t *mtp) 3518 { 3519 for (const sym_t *mem = utp->t_sou->sou_first_member; 3520 mem != NULL; mem = mem->s_next) { 3521 if (types_compatible(mem->s_type, mtp, true, false, NULL)) 3522 return true; 3523 } 3524 return false; 3525 } 3526 3527 static bool 3528 should_warn_about_pointer_cast(const type_t *nstp, tspec_t nst, 3529 const type_t *ostp, tspec_t ost) 3530 { 3531 3532 while (nst == ARRAY) 3533 nstp = nstp->t_subt, nst = nstp->t_tspec; 3534 while (ost == ARRAY) 3535 ostp = ostp->t_subt, ost = ostp->t_tspec; 3536 3537 if (nst == STRUCT && ost == STRUCT && 3538 (struct_starts_with(nstp, ostp) || 3539 struct_starts_with(ostp, nstp))) 3540 return false; 3541 3542 if (is_incomplete(nstp) || is_incomplete(ostp)) 3543 return false; 3544 3545 if (nst == CHAR || nst == UCHAR) 3546 return false; /* for the sake of traditional C code */ 3547 if (ost == CHAR || ost == UCHAR) 3548 return false; /* for the sake of traditional C code */ 3549 3550 /* Allow cast between pointers to sockaddr variants. */ 3551 if (nst == STRUCT && ost == STRUCT) { 3552 const sym_t *nmem = nstp->t_sou->sou_first_member; 3553 const sym_t *omem = ostp->t_sou->sou_first_member; 3554 while (nmem != NULL && omem != NULL && 3555 types_compatible(nmem->s_type, omem->s_type, 3556 true, false, NULL)) 3557 nmem = nmem->s_next, omem = omem->s_next; 3558 if (nmem != NULL && is_byte_array(nmem->s_type)) 3559 return false; 3560 if (omem != NULL && is_byte_array(omem->s_type)) 3561 return false; 3562 if (nmem == NULL && omem == NULL) 3563 return false; 3564 } 3565 3566 if (nst == UNION || ost == UNION) { 3567 const type_t *union_tp = nst == UNION ? nstp : ostp; 3568 const type_t *other_tp = nst == UNION ? ostp : nstp; 3569 if (union_contains(union_tp, other_tp)) 3570 return false; 3571 } 3572 3573 if (is_struct_or_union(nst) && is_struct_or_union(ost)) 3574 return nstp->t_sou != ostp->t_sou; 3575 3576 enum rank_kind rk1 = type_properties(nst)->tt_rank_kind; 3577 enum rank_kind rk2 = type_properties(ost)->tt_rank_kind; 3578 if (rk1 != rk2 || rk1 == RK_NONE) 3579 return true; 3580 3581 return portable_rank_cmp(nst, ost) != 0; 3582 } 3583 3584 static void 3585 convert_pointer_from_pointer(type_t *ntp, tnode_t *tn) 3586 { 3587 const type_t *nstp = ntp->t_subt; 3588 const type_t *otp = tn->tn_type; 3589 const type_t *ostp = otp->t_subt; 3590 tspec_t nst = nstp->t_tspec; 3591 tspec_t ost = ostp->t_tspec; 3592 3593 if (nst == VOID || ost == VOID) { 3594 /* TODO: C99 behaves like C90 here. */ 3595 if ((!allow_trad && !allow_c99) && (nst == FUNC || ost == FUNC)) { 3596 const char *nts, *ots; 3597 /* null pointers are already handled in convert() */ 3598 *(nst == FUNC ? &nts : &ots) = "function pointer"; 3599 *(nst == VOID ? &nts : &ots) = "'void *'"; 3600 /* conversion of %s to %s requires a cast */ 3601 warning(303, ots, nts); 3602 } 3603 return; 3604 } 3605 if (nst == FUNC && ost == FUNC) 3606 return; 3607 if (nst == FUNC || ost == FUNC) { 3608 /* converting '%s' to '%s' is questionable */ 3609 warning(229, type_name(otp), type_name(ntp)); 3610 return; 3611 } 3612 3613 if (hflag && alignment_in_bits(nstp) > alignment_in_bits(ostp) && 3614 ost != CHAR && ost != UCHAR && 3615 !is_incomplete(ostp) && 3616 !(nst == UNION && union_contains(nstp, ostp))) { 3617 /* converting '%s' to '%s' increases alignment ... */ 3618 warning(135, type_name(otp), type_name(ntp), 3619 alignment_in_bits(ostp) / CHAR_SIZE, 3620 alignment_in_bits(nstp) / CHAR_SIZE); 3621 } 3622 3623 if (cflag && should_warn_about_pointer_cast(nstp, nst, ostp, ost)) { 3624 /* pointer cast from '%s' to '%s' may be troublesome */ 3625 warning(247, type_name(otp), type_name(ntp)); 3626 } 3627 } 3628 3629 /* 3630 * Insert a conversion operator, which converts the type of the node 3631 * to another given type. 3632 * 3633 * Possible values for 'op': 3634 * CVT a cast-expression 3635 * binary integer promotion for one of the operands, or a usual 3636 * arithmetic conversion 3637 * binary plain or compound assignments to bit-fields 3638 * FARG 'arg' is the number of the parameter (used for warnings) 3639 * NOOP several other implicit conversions 3640 * ... 3641 */ 3642 tnode_t * 3643 convert(op_t op, int arg, type_t *tp, tnode_t *tn) 3644 { 3645 tspec_t nt = tp->t_tspec; 3646 tspec_t ot = tn->tn_type->t_tspec; 3647 3648 if (allow_trad && allow_c90 && op == FARG) 3649 check_prototype_conversion(arg, nt, ot, tp, tn); 3650 3651 if (nt == BOOL) { 3652 /* No further checks. */ 3653 3654 } else if (is_integer(nt)) { 3655 if (ot == BOOL) { 3656 /* No further checks. */ 3657 } else if (is_integer(ot)) 3658 convert_integer_from_integer(op, arg, nt, ot, tp, tn); 3659 else if (is_floating(ot)) 3660 convert_integer_from_floating(op, tp, tn); 3661 else if (ot == PTR) 3662 convert_integer_from_pointer(op, nt, tp, tn); 3663 3664 } else if (is_floating(nt)) { 3665 /* No further checks. */ 3666 3667 } else if (nt == PTR) { 3668 if (is_null_pointer(tn)) { 3669 /* a null pointer may be assigned to any pointer. */ 3670 } else if (ot == PTR && op == CVT) 3671 convert_pointer_from_pointer(tp, tn); 3672 } 3673 3674 tnode_t *ntn = expr_alloc_tnode(); 3675 ntn->tn_op = CVT; 3676 ntn->tn_type = tp; 3677 ntn->tn_cast = op == CVT; 3678 ntn->tn_sys |= tn->tn_sys; 3679 ntn->tn_right = NULL; 3680 if (tn->tn_op != CON || nt == VOID) { 3681 ntn->tn_left = tn; 3682 } else { 3683 ntn->tn_op = CON; 3684 convert_constant(op, arg, ntn->tn_type, &ntn->tn_val, 3685 &tn->tn_val); 3686 } 3687 3688 return ntn; 3689 } 3690 3691 static void 3692 convert_constant_floating(op_t op, int arg, tspec_t ot, const type_t *tp, 3693 tspec_t nt, val_t *v, val_t *nv) 3694 { 3695 long double max = 0.0, min = 0.0; 3696 3697 switch (nt) { 3698 case CHAR: 3699 max = TARG_CHAR_MAX; min = TARG_CHAR_MIN; break; 3700 case UCHAR: 3701 max = TARG_UCHAR_MAX; min = 0; break; 3702 case SCHAR: 3703 max = TARG_SCHAR_MAX; min = TARG_SCHAR_MIN; break; 3704 case SHORT: 3705 max = TARG_SHRT_MAX; min = TARG_SHRT_MIN; break; 3706 case USHORT: 3707 max = TARG_USHRT_MAX; min = 0; break; 3708 case ENUM: 3709 case INT: 3710 max = TARG_INT_MAX; min = TARG_INT_MIN; break; 3711 case UINT: 3712 max = TARG_UINT_MAX; min = 0; break; 3713 case LONG: 3714 max = TARG_LONG_MAX; min = TARG_LONG_MIN; break; 3715 case ULONG: 3716 max = TARG_ULONG_MAX; min = 0; break; 3717 case LLONG: 3718 max = LLONG_MAX; min = LLONG_MIN; break; 3719 case ULLONG: 3720 max = ULLONG_MAX; min = 0; break; 3721 case FLOAT: 3722 case FCOMPLEX: 3723 max = FLT_MAX; min = -FLT_MAX; break; 3724 case DOUBLE: 3725 case DCOMPLEX: 3726 max = DBL_MAX; min = -DBL_MAX; break; 3727 case PTR: 3728 /* Already got an error because of float --> ptr */ 3729 case LDOUBLE: 3730 case LCOMPLEX: 3731 /* LINTED 248 */ 3732 max = LDBL_MAX; min = -max; break; 3733 default: 3734 lint_assert(/*CONSTCOND*/false); 3735 } 3736 if (v->u.floating > max || v->u.floating < min) { 3737 lint_assert(nt != LDOUBLE); 3738 if (op == FARG) { 3739 /* conversion of '%s' to '%s' is out of range, ... */ 3740 warning(295, 3741 type_name(gettyp(ot)), type_name(tp), arg); 3742 } else { 3743 /* conversion of '%s' to '%s' is out of range */ 3744 warning(119, type_name(gettyp(ot)), type_name(tp)); 3745 } 3746 v->u.floating = v->u.floating > 0 ? max : min; 3747 } 3748 3749 if (nt == FLOAT || nt == FCOMPLEX) 3750 nv->u.floating = (float)v->u.floating; 3751 else if (nt == DOUBLE || nt == DCOMPLEX) 3752 nv->u.floating = (double)v->u.floating; 3753 else if (nt == LDOUBLE || nt == LCOMPLEX) 3754 nv->u.floating = v->u.floating; 3755 else 3756 nv->u.integer = (int64_t)v->u.floating; 3757 } 3758 3759 static bool 3760 convert_constant_to_floating(tspec_t nt, val_t *nv, 3761 tspec_t ot, const val_t *v) 3762 { 3763 if (nt == FLOAT) { 3764 nv->u.floating = (ot == PTR || is_uinteger(ot)) ? 3765 (float)(uint64_t)v->u.integer : (float)v->u.integer; 3766 } else if (nt == DOUBLE) { 3767 nv->u.floating = (ot == PTR || is_uinteger(ot)) ? 3768 (double)(uint64_t)v->u.integer : (double)v->u.integer; 3769 } else if (nt == LDOUBLE) { 3770 nv->u.floating = (ot == PTR || is_uinteger(ot)) 3771 ? (long double)(uint64_t)v->u.integer 3772 : (long double)v->u.integer; 3773 } else 3774 return false; 3775 return true; 3776 } 3777 3778 /* 3779 * Print a warning if bits which were set are lost due to the conversion. 3780 * This can happen with operator ORASS only. 3781 */ 3782 static void 3783 convert_constant_check_range_bitor(size_t nsz, size_t osz, const val_t *v, 3784 uint64_t xmask, op_t op) 3785 { 3786 if (nsz < osz && (v->u.integer & xmask) != 0) { 3787 /* constant truncated by conversion, op '%s' */ 3788 warning(306, op_name(op)); 3789 } 3790 } 3791 3792 /* 3793 * Print a warning if additional bits are not all 1 3794 * and the most significant bit of the old value is 1, 3795 * or if at least one (but not all) removed bit was 0. 3796 */ 3797 static void 3798 convert_constant_check_range_bitand(size_t nsz, size_t osz, 3799 uint64_t xmask, const val_t *nv, 3800 tspec_t ot, const val_t *v, 3801 const type_t *tp, op_t op) 3802 { 3803 if (nsz > osz && 3804 (nv->u.integer & bit((unsigned int)(osz - 1))) != 0 && 3805 (nv->u.integer & xmask) != xmask) { 3806 /* extra bits set to 0 in conversion of '%s' to '%s', ... */ 3807 warning(309, type_name(gettyp(ot)), 3808 type_name(tp), op_name(op)); 3809 } else if (nsz < osz && 3810 (v->u.integer & xmask) != xmask && 3811 (v->u.integer & xmask) != 0) { 3812 /* constant truncated by conversion, op '%s' */ 3813 warning(306, op_name(op)); 3814 } 3815 } 3816 3817 static void 3818 convert_constant_check_range_signed(op_t op, int arg) 3819 { 3820 if (op == ASSIGN) { 3821 /* assignment of negative constant to unsigned type */ 3822 warning(164); 3823 } else if (op == INIT) { 3824 /* initialization of unsigned with negative constant */ 3825 warning(221); 3826 } else if (op == FARG) { 3827 /* conversion of negative constant to unsigned type, ... */ 3828 warning(296, arg); 3829 } else if (modtab[op].m_comparison) { 3830 /* handled by check_integer_comparison() */ 3831 } else { 3832 /* conversion of negative constant to unsigned type */ 3833 warning(222); 3834 } 3835 } 3836 3837 /* 3838 * Loss of significant bit(s). All truncated bits of unsigned types or all 3839 * truncated bits plus the msb of the target for signed types are considered 3840 * to be significant bits. Loss of significant bits means that at least one 3841 * of the bits was set in an unsigned type or that at least one but not all 3842 * of the bits was set in a signed type. Loss of significant bits means that 3843 * it is not possible, also not with necessary casts, to convert back to the 3844 * original type. An example for a necessary cast is: 3845 * char c; int i; c = 128; 3846 * i = c; ** yields -128 ** 3847 * i = (unsigned char)c; ** yields 128 ** 3848 */ 3849 static void 3850 warn_constant_check_range_truncated(op_t op, int arg, const type_t *tp, 3851 tspec_t ot) 3852 { 3853 if (op == ASSIGN && tp->t_bitfield) 3854 /* precision lost in bit-field assignment */ 3855 warning(166); 3856 else if (op == ASSIGN) 3857 /* constant truncated by assignment */ 3858 warning(165); 3859 else if (op == INIT && tp->t_bitfield) 3860 /* bit-field initializer does not fit */ 3861 warning(180); 3862 else if (op == INIT) 3863 /* initializer does not fit */ 3864 warning(178); 3865 else if (op == CASE) 3866 /* case label affected by conversion */ 3867 warning(196); 3868 else if (op == FARG) 3869 /* conversion of '%s' to '%s' is out of range, arg #%d */ 3870 warning(295, type_name(gettyp(ot)), type_name(tp), arg); 3871 else 3872 /* conversion of '%s' to '%s' is out of range */ 3873 warning(119, type_name(gettyp(ot)), type_name(tp)); 3874 } 3875 3876 static void 3877 warn_constant_check_range_loss(op_t op, int arg, const type_t *tp, 3878 tspec_t ot) 3879 { 3880 if (op == ASSIGN && tp->t_bitfield) 3881 /* precision lost in bit-field assignment */ 3882 warning(166); 3883 else if (op == INIT && tp->t_bitfield) 3884 /* bit-field initializer out of range */ 3885 warning(11); 3886 else if (op == CASE) 3887 /* case label affected by conversion */ 3888 warning(196); 3889 else if (op == FARG) 3890 /* conversion of '%s' to '%s' is out of range, arg #%d */ 3891 warning(295, type_name(gettyp(ot)), type_name(tp), arg); 3892 else 3893 /* conversion of '%s' to '%s' is out of range */ 3894 warning(119, type_name(gettyp(ot)), type_name(tp)); 3895 } 3896 3897 static void 3898 convert_constant_check_range(tspec_t ot, const type_t *tp, tspec_t nt, 3899 op_t op, int arg, const val_t *v, val_t *nv) 3900 { 3901 unsigned int obitsz, nbitsz; 3902 uint64_t xmask, xmsk1; 3903 3904 obitsz = size_in_bits(ot); 3905 nbitsz = tp->t_bitfield ? tp->t_bit_field_width : size_in_bits(nt); 3906 xmask = value_bits(nbitsz) ^ value_bits(obitsz); 3907 xmsk1 = value_bits(nbitsz) ^ value_bits(obitsz - 1); 3908 /* 3909 * For bitwise operations we are not interested in the arithmetic 3910 * value, but in the bits itself. 3911 */ 3912 if (op == ORASS || op == BITOR || op == BITXOR) { 3913 convert_constant_check_range_bitor( 3914 nbitsz, obitsz, v, xmask, op); 3915 } else if (op == ANDASS || op == BITAND) { 3916 convert_constant_check_range_bitand( 3917 nbitsz, obitsz, xmask, nv, ot, v, tp, op); 3918 } else if ((nt != PTR && is_uinteger(nt)) && 3919 (ot != PTR && !is_uinteger(ot)) && 3920 v->u.integer < 0) 3921 convert_constant_check_range_signed(op, arg); 3922 else if (nv->u.integer != v->u.integer && nbitsz <= obitsz && 3923 (v->u.integer & xmask) != 0 && 3924 (is_uinteger(ot) || (v->u.integer & xmsk1) != xmsk1)) 3925 warn_constant_check_range_truncated(op, arg, tp, ot); 3926 else if (nv->u.integer != v->u.integer) 3927 warn_constant_check_range_loss(op, arg, tp, ot); 3928 } 3929 3930 /*- 3931 * Converts a typed constant to a constant of another type. 3932 * 3933 * op operator which requires conversion 3934 * arg if op is FARG, # of parameter 3935 * tp type to which to convert the constant 3936 * nv new constant 3937 * v old constant 3938 */ 3939 void 3940 convert_constant(op_t op, int arg, const type_t *tp, val_t *nv, val_t *v) 3941 { 3942 /* 3943 * TODO: make 'v' const; the name of this function does not suggest 3944 * that it modifies 'v'. 3945 */ 3946 tspec_t ot = v->v_tspec; 3947 tspec_t nt = nv->v_tspec = tp->t_tspec; 3948 bool range_check = false; 3949 3950 if (nt == BOOL) { /* C99 6.3.1.2 */ 3951 nv->v_unsigned_since_c90 = false; 3952 nv->u.integer = is_nonzero_val(v) ? 1 : 0; 3953 return; 3954 } 3955 3956 if (ot == FLOAT || ot == DOUBLE || ot == LDOUBLE) 3957 convert_constant_floating(op, arg, ot, tp, nt, v, nv); 3958 else if (!convert_constant_to_floating(nt, nv, ot, v)) { 3959 range_check = true; /* Check for lost precision. */ 3960 nv->u.integer = v->u.integer; 3961 } 3962 3963 if (allow_trad && allow_c90 && v->v_unsigned_since_c90 && 3964 (is_floating(nt) || ( 3965 (is_integer(nt) && !is_uinteger(nt) && 3966 portable_rank_cmp(nt, ot) > 0)))) { 3967 /* C90 treats constant as unsigned */ 3968 warning(157); 3969 v->v_unsigned_since_c90 = false; 3970 } 3971 3972 if (is_integer(nt)) { 3973 nv->u.integer = convert_integer(nv->u.integer, nt, 3974 tp->t_bitfield ? tp->t_bit_field_width : size_in_bits(nt)); 3975 } 3976 3977 if (range_check && op != CVT) 3978 convert_constant_check_range(ot, tp, nt, op, arg, v, nv); 3979 } 3980 3981 /* 3982 * Create a constant node for sizeof. 3983 */ 3984 tnode_t * 3985 build_sizeof(const type_t *tp) 3986 { 3987 unsigned int size_in_bytes = type_size_in_bits(tp) / CHAR_SIZE; 3988 tnode_t *tn = build_integer_constant(SIZEOF_TSPEC, size_in_bytes); 3989 tn->tn_system_dependent = true; 3990 debug_step("build_sizeof '%s' = %u", type_name(tp), size_in_bytes); 3991 return tn; 3992 } 3993 3994 /* 3995 * Create a constant node for offsetof. 3996 */ 3997 tnode_t * 3998 build_offsetof(const type_t *tp, const sym_t *sym) 3999 { 4000 unsigned int offset_in_bits = 0; 4001 4002 if (!is_struct_or_union(tp->t_tspec)) { 4003 /* unacceptable operand of '%s' */ 4004 error(111, "offsetof"); 4005 goto proceed; 4006 } 4007 sym_t *mem = find_member(tp->t_sou, sym->s_name); 4008 if (mem == NULL) { 4009 /* type '%s' does not have member '%s' */ 4010 error(101, sym->s_name, type_name(tp)); 4011 goto proceed; 4012 } 4013 offset_in_bits = mem->u.s_member.sm_offset_in_bits; 4014 4015 proceed:; 4016 unsigned int offset_in_bytes = offset_in_bits / CHAR_SIZE; 4017 tnode_t *tn = build_integer_constant(SIZEOF_TSPEC, offset_in_bytes); 4018 tn->tn_system_dependent = true; 4019 return tn; 4020 } 4021 4022 unsigned int 4023 type_size_in_bits(const type_t *tp) 4024 { 4025 4026 unsigned int elem = 1; 4027 bool flex = false; 4028 lint_assert(tp != NULL); 4029 while (tp->t_tspec == ARRAY) { 4030 flex = true; /* allow c99 flex arrays [] [0] */ 4031 elem *= tp->t_dim; 4032 tp = tp->t_subt; 4033 } 4034 if (elem == 0 && !flex) { 4035 /* cannot take size/alignment of incomplete type */ 4036 error(143); 4037 elem = 1; 4038 } 4039 4040 unsigned int elsz; 4041 switch (tp->t_tspec) { 4042 case VOID: 4043 /* cannot take size/alignment of void */ 4044 error(146); 4045 elsz = 1; 4046 break; 4047 case FUNC: 4048 /* cannot take size/alignment of function type '%s' */ 4049 error(144, type_name(tp)); 4050 elsz = 1; 4051 break; 4052 case STRUCT: 4053 case UNION: 4054 if (is_incomplete(tp)) { 4055 /* cannot take size/alignment of incomplete type */ 4056 error(143); 4057 elsz = 1; 4058 } else { 4059 elsz = tp->t_sou->sou_size_in_bits; 4060 } 4061 break; 4062 case ENUM: 4063 if (is_incomplete(tp)) { 4064 /* cannot take size/alignment of incomplete type */ 4065 warning(143); 4066 } 4067 /* FALLTHROUGH */ 4068 default: 4069 if (tp->t_bitfield) { 4070 /* cannot take size/alignment of bit-field */ 4071 error(145); 4072 } 4073 elsz = size_in_bits(tp->t_tspec); 4074 lint_assert(elsz > 0); 4075 break; 4076 } 4077 4078 return elem * elsz; 4079 } 4080 4081 /* C11 6.5.3.4, GCC */ 4082 tnode_t * 4083 build_alignof(const type_t *tp) 4084 { 4085 if (tp->t_tspec == FUNC) { 4086 /* cannot take size/alignment of function type '%s' */ 4087 error(144, type_name(tp)); 4088 return NULL; 4089 } 4090 if (tp->t_tspec == VOID) { 4091 /* cannot take size/alignment of void */ 4092 error(146); 4093 return NULL; 4094 } 4095 if (is_incomplete(tp)) { 4096 /* cannot take size/alignment of incomplete type */ 4097 error(143); 4098 return NULL; 4099 } 4100 if (tp->t_bitfield) { 4101 /* cannot take size/alignment of bit-field */ 4102 error(145); 4103 return NULL; 4104 } 4105 return build_integer_constant(SIZEOF_TSPEC, 4106 (int64_t)alignment_in_bits(tp) / CHAR_SIZE); 4107 } 4108 4109 static tnode_t * 4110 cast_to_union(tnode_t *otn, type_t *ntp) 4111 { 4112 4113 if (!allow_gcc) { 4114 /* union cast is a GCC extension */ 4115 error(328); 4116 return NULL; 4117 } 4118 4119 for (const sym_t *m = ntp->t_sou->sou_first_member; 4120 m != NULL; m = m->s_next) { 4121 if (types_compatible(m->s_type, otn->tn_type, 4122 false, false, NULL)) { 4123 tnode_t *ntn = expr_alloc_tnode(); 4124 ntn->tn_op = CVT; 4125 ntn->tn_type = ntp; 4126 ntn->tn_cast = true; 4127 ntn->tn_left = otn; 4128 ntn->tn_right = NULL; 4129 return ntn; 4130 } 4131 } 4132 4133 /* type '%s' is not a member of '%s' */ 4134 error(329, type_name(otn->tn_type), type_name(ntp)); 4135 return NULL; 4136 } 4137 4138 /* 4139 * Type casts. 4140 */ 4141 tnode_t * 4142 cast(tnode_t *tn, type_t *tp) 4143 { 4144 4145 if (tn == NULL) 4146 return NULL; 4147 4148 tn = cconv(tn); 4149 4150 lint_assert(tp != NULL); 4151 tspec_t nt = tp->t_tspec; 4152 tspec_t ot = tn->tn_type->t_tspec; 4153 4154 if (nt == VOID) { 4155 /* 4156 * C90 6.3.4, C99 6.5.4p2 and C11 6.5.4p2 allow any type to 4157 * be cast to void. The only other allowed casts are from a 4158 * scalar type to a scalar type. 4159 */ 4160 } else if (nt == UNION) 4161 return cast_to_union(tn, tp); 4162 else if (nt == STRUCT || nt == ARRAY || nt == FUNC) { 4163 /* Casting to a struct is an undocumented GCC extension. */ 4164 if (!(allow_gcc && nt == STRUCT)) 4165 goto invalid_cast; 4166 } else if (is_struct_or_union(ot)) 4167 goto invalid_cast; 4168 else if (ot == VOID) { 4169 /* improper cast of void expression */ 4170 error(148); 4171 return NULL; 4172 } else if (is_integer(nt) && is_scalar(ot)) { 4173 /* ok */ 4174 } else if (is_floating(nt) && is_arithmetic(ot)) { 4175 /* ok */ 4176 } else if (nt == PTR && is_integer(ot)) { 4177 /* ok */ 4178 } else if (nt == PTR && ot == PTR) { 4179 if (!tp->t_subt->t_const && tn->tn_type->t_subt->t_const) { 4180 if (hflag) 4181 /* cast discards 'const' from type '%s' */ 4182 warning(275, type_name(tn->tn_type)); 4183 } 4184 } else 4185 goto invalid_cast; 4186 4187 if (any_query_enabled && types_compatible(tp, tn->tn_type, 4188 false, false, NULL)) { 4189 /* no-op cast from '%s' to '%s' */ 4190 query_message(6, type_name(tn->tn_type), type_name(tp)); 4191 } 4192 4193 tn = convert(CVT, 0, tp, tn); 4194 tn->tn_cast = true; 4195 4196 return tn; 4197 4198 invalid_cast: 4199 /* invalid cast from '%s' to '%s' */ 4200 error(147, type_name(tn->tn_type), type_name(tp)); 4201 return NULL; 4202 } 4203 4204 /* 4205 * Create the node for a function argument. 4206 * All necessary conversions and type checks are done in 4207 * build_function_call because build_function_argument has no 4208 * information about the expected parameter types. 4209 */ 4210 tnode_t * 4211 build_function_argument(tnode_t *args, tnode_t *arg) 4212 { 4213 /* 4214 * If there was a serious error in the expression for the argument, 4215 * create a dummy argument so the positions of the remaining arguments 4216 * will not change. 4217 */ 4218 if (arg == NULL) 4219 arg = build_integer_constant(INT, 0); 4220 4221 return build_op(PUSH, arg->tn_sys, arg->tn_type, arg, args); 4222 } 4223 4224 /* 4225 * Compare the type of an argument with the corresponding type of a 4226 * prototype parameter. If it is a valid combination, but both types 4227 * are not the same, insert a conversion to convert the argument into 4228 * the type of the parameter. 4229 */ 4230 static tnode_t * 4231 check_prototype_argument( 4232 int n, /* pos of arg */ 4233 type_t *tp, /* expected type (from prototype) */ 4234 tnode_t *tn) /* argument */ 4235 { 4236 tnode_t *ln = xcalloc(1, sizeof(*ln)); 4237 ln->tn_type = expr_unqualified_type(tp); 4238 ln->tn_lvalue = true; 4239 if (typeok(FARG, n, ln, tn)) { 4240 bool dowarn; 4241 if (!types_compatible(tp, tn->tn_type, 4242 true, false, (dowarn = false, &dowarn)) || dowarn) 4243 tn = convert(FARG, n, tp, tn); 4244 } 4245 free(ln); 4246 return tn; 4247 } 4248 4249 /* 4250 * Check types of all function arguments and insert conversions, 4251 * if necessary. 4252 */ 4253 static tnode_t * 4254 check_function_arguments(type_t *ftp, tnode_t *args) 4255 { 4256 /* get # of parameters in the prototype */ 4257 int npar = 0; 4258 for (const sym_t *p = ftp->t_params; p != NULL; p = p->s_next) 4259 npar++; 4260 4261 /* get # of arguments in the function call */ 4262 int narg = 0; 4263 for (const tnode_t *arg = args; arg != NULL; arg = arg->tn_right) 4264 narg++; 4265 4266 const sym_t *param = ftp->t_params; 4267 if (ftp->t_proto && npar != narg && !(ftp->t_vararg && npar < narg)) { 4268 /* argument mismatch: %d %s passed, %d expected */ 4269 error(150, narg, narg != 1 ? "arguments" : "argument", npar); 4270 param = NULL; 4271 } 4272 4273 for (int n = 1; n <= narg; n++) { 4274 4275 // The rightmost argument starts the argument list. 4276 tnode_t *arg = args; 4277 for (int i = narg; i > n; i--, arg = arg->tn_right) 4278 continue; 4279 4280 /* some things which are always not allowed */ 4281 tspec_t at = arg->tn_left->tn_type->t_tspec; 4282 if (at == VOID) { 4283 /* void expressions may not be arguments, arg #%d */ 4284 error(151, n); 4285 return NULL; 4286 } 4287 if (is_struct_or_union(at) && 4288 is_incomplete(arg->tn_left->tn_type)) { 4289 /* argument cannot have unknown size, arg #%d */ 4290 error(152, n); 4291 return NULL; 4292 } 4293 if (is_integer(at) && 4294 arg->tn_left->tn_type->t_is_enum && 4295 is_incomplete(arg->tn_left->tn_type)) { 4296 /* argument cannot have unknown size, arg #%d */ 4297 warning(152, n); 4298 } 4299 4300 /* class conversions (arg in value context) */ 4301 arg->tn_left = cconv(arg->tn_left); 4302 4303 if (param != NULL) { 4304 arg->tn_left = check_prototype_argument( 4305 n, param->s_type, arg->tn_left); 4306 } else 4307 arg->tn_left = promote(NOOP, true, arg->tn_left); 4308 arg->tn_type = arg->tn_left->tn_type; 4309 4310 if (param != NULL) 4311 param = param->s_next; 4312 } 4313 4314 return args; 4315 } 4316 4317 /* 4318 * Create the node for a function call. Also check types of 4319 * function arguments and insert conversions, if necessary. 4320 */ 4321 tnode_t * 4322 build_function_call(tnode_t *func, bool sys, tnode_t *args) 4323 { 4324 4325 if (func == NULL) 4326 return NULL; 4327 4328 op_t fcop = func->tn_op == NAME && func->tn_type->t_tspec == FUNC 4329 ? CALL : ICALL; 4330 4331 check_ctype_function_call(func, args); 4332 4333 /* Turn the function name into a pointer to the function. */ 4334 func = cconv(func); 4335 4336 if (func->tn_type->t_tspec != PTR || 4337 func->tn_type->t_subt->t_tspec != FUNC) { 4338 /* cannot call '%s', must be a function */ 4339 error(149, type_name(func->tn_type)); 4340 return NULL; 4341 } 4342 4343 args = check_function_arguments(func->tn_type->t_subt, args); 4344 4345 return build_op(fcop, sys, func->tn_type->t_subt->t_subt, func, args); 4346 } 4347 4348 /* 4349 * Return the value of an integral constant expression. 4350 * If the expression is not constant or its type is not an integer 4351 * type, an error message is printed. 4352 */ 4353 val_t * 4354 integer_constant(tnode_t *tn, bool required) 4355 { 4356 4357 if (tn != NULL) 4358 tn = cconv(tn); 4359 if (tn != NULL) 4360 tn = promote(NOOP, false, tn); 4361 4362 val_t *v = xcalloc(1, sizeof(*v)); 4363 4364 if (tn == NULL) { 4365 lint_assert(seen_error); 4366 debug_step("constant node is null; returning 1 instead"); 4367 v->v_tspec = INT; 4368 v->u.integer = 1; 4369 return v; 4370 } 4371 4372 v->v_tspec = tn->tn_type->t_tspec; 4373 4374 if (tn->tn_op == CON) { 4375 lint_assert(tn->tn_type->t_tspec == tn->tn_val.v_tspec); 4376 if (is_integer(tn->tn_val.v_tspec)) { 4377 v->v_unsigned_since_c90 = 4378 tn->tn_val.v_unsigned_since_c90; 4379 v->u.integer = tn->tn_val.u.integer; 4380 return v; 4381 } 4382 v->u.integer = (int64_t)tn->tn_val.u.floating; 4383 } else { 4384 v->u.integer = 1; 4385 } 4386 4387 if (required) 4388 /* integral constant expression expected */ 4389 error(55); 4390 else 4391 /* variable array dimension is a C99/GCC extension */ 4392 c99ism(318); 4393 4394 if (!is_integer(v->v_tspec)) 4395 v->v_tspec = INT; 4396 4397 return v; 4398 } 4399 4400 static bool 4401 is_constcond_false(const tnode_t *tn, tspec_t t) 4402 { 4403 return (t == BOOL || t == INT) && 4404 tn->tn_op == CON && tn->tn_val.u.integer == 0; 4405 } 4406 4407 /* 4408 * Perform some tests on expressions which can't be done in build_binary() 4409 * and functions called by build_binary(). These tests must be done here 4410 * because we need some information about the context in which the operations 4411 * are performed. 4412 * After all tests are performed and dofreeblk is true, expr() frees the 4413 * memory which is used for the expression. 4414 */ 4415 void 4416 expr(tnode_t *tn, bool vctx, bool cond, bool dofreeblk, bool is_do_while) 4417 { 4418 4419 if (tn == NULL) { /* in case of errors */ 4420 expr_free_all(); 4421 return; 4422 } 4423 4424 /* expr() is also called in global initializations */ 4425 if (dcs->d_kind != DLK_EXTERN && !is_do_while) 4426 check_statement_reachable(); 4427 4428 check_expr_misc(tn, vctx, cond, !cond, false, false, false); 4429 if (tn->tn_op == ASSIGN && !tn->tn_parenthesized) { 4430 if (hflag && cond) 4431 /* assignment in conditional context */ 4432 warning(159); 4433 } else if (tn->tn_op == CON) { 4434 if (hflag && cond && !suppress_constcond && 4435 !tn->tn_system_dependent && 4436 !(is_do_while && 4437 is_constcond_false(tn, tn->tn_type->t_tspec))) 4438 /* constant in conditional context */ 4439 warning(161); 4440 } 4441 if (!modtab[tn->tn_op].m_has_side_effect) { 4442 /* 4443 * for left operands of COMMA this warning is already 4444 * printed 4445 */ 4446 if (tn->tn_op != COMMA && !vctx && !cond) 4447 check_null_effect(tn); 4448 } 4449 debug_node(tn); 4450 4451 /* free the tree memory */ 4452 if (dofreeblk) 4453 expr_free_all(); 4454 } 4455 4456 /* 4457 * Checks the range of array indices, if possible. 4458 * amper is set if only the address of the element is used. This 4459 * means that the index is allowed to refer to the first element 4460 * after the array. 4461 */ 4462 static void 4463 check_array_index(tnode_t *tn, bool amper) 4464 { 4465 const tnode_t *ln = tn->tn_left; 4466 const tnode_t *rn = tn->tn_right; 4467 4468 /* We can only check constant indices. */ 4469 if (rn->tn_op != CON) 4470 return; 4471 4472 /* Return if the left node does not stem from an array. */ 4473 if (ln->tn_op != ADDR) 4474 return; 4475 if (ln->tn_left->tn_op != STRING && ln->tn_left->tn_op != NAME) 4476 return; 4477 if (ln->tn_left->tn_type->t_tspec != ARRAY) 4478 return; 4479 4480 /* 4481 * For incomplete array types, we can print a warning only if 4482 * the index is negative. 4483 */ 4484 if (is_incomplete(ln->tn_left->tn_type) && rn->tn_val.u.integer >= 0) 4485 return; 4486 4487 /* Get the size of one array element */ 4488 int elsz = length_in_bits(ln->tn_type->t_subt, NULL); 4489 if (elsz == 0) 4490 return; 4491 elsz /= CHAR_SIZE; 4492 4493 /* Change the unit of the index from bytes to element size. */ 4494 int64_t con = is_uinteger(rn->tn_type->t_tspec) 4495 ? (int64_t)((uint64_t)rn->tn_val.u.integer / elsz) 4496 : rn->tn_val.u.integer / elsz; 4497 4498 int dim = ln->tn_left->tn_type->t_dim + (amper ? 1 : 0); 4499 4500 if (!is_uinteger(rn->tn_type->t_tspec) && con < 0) { 4501 /* array subscript cannot be negative: %ld */ 4502 warning(167, (long)con); 4503 } else if (dim > 0 && (uint64_t)con >= (uint64_t)dim) { 4504 /* array subscript cannot be > %d: %ld */ 4505 warning(168, dim - 1, (long)con); 4506 } 4507 } 4508 4509 static void 4510 check_expr_addr(const tnode_t *ln, bool szof, bool fcall) 4511 { 4512 /* XXX: Taking warn_about_unreachable into account here feels wrong. */ 4513 if (ln->tn_op == NAME && (reached || !warn_about_unreachable)) { 4514 if (!szof) 4515 mark_as_set(ln->tn_sym); 4516 mark_as_used(ln->tn_sym, fcall, szof); 4517 } 4518 if (ln->tn_op == INDIR && ln->tn_left->tn_op == PLUS) 4519 /* check the range of array indices */ 4520 check_array_index(ln->tn_left, true); 4521 } 4522 4523 static void 4524 check_expr_load(const tnode_t *ln) 4525 { 4526 if (ln->tn_op == INDIR && ln->tn_left->tn_op == PLUS) 4527 /* check the range of array indices */ 4528 check_array_index(ln->tn_left, false); 4529 } 4530 4531 /* 4532 * If there is an asm statement in one of the compound statements around, 4533 * there may be other side effects, so don't warn. 4534 */ 4535 static bool 4536 is_asm_around(void) 4537 { 4538 for (decl_level *dl = dcs; dl != NULL; dl = dl->d_enclosing) 4539 if (dl->d_asm) 4540 return true; 4541 return false; 4542 } 4543 4544 static void 4545 check_expr_side_effect(const tnode_t *ln, bool szof) 4546 { 4547 4548 /* XXX: Taking warn_about_unreachable into account here feels wrong. */ 4549 if (ln->tn_op == NAME && (reached || !warn_about_unreachable)) { 4550 scl_t sc = ln->tn_sym->s_scl; 4551 if (sc != EXTERN && sc != STATIC && 4552 !ln->tn_sym->s_set && !szof && !is_asm_around()) { 4553 /* '%s' may be used before set */ 4554 warning(158, ln->tn_sym->s_name); 4555 mark_as_set(ln->tn_sym); 4556 } 4557 mark_as_used(ln->tn_sym, false, false); 4558 } 4559 } 4560 4561 static void 4562 check_expr_assign(const tnode_t *ln, bool szof) 4563 { 4564 /* XXX: Taking warn_about_unreachable into account here feels wrong. */ 4565 if (ln->tn_op == NAME && !szof && (reached || !warn_about_unreachable)) { 4566 mark_as_set(ln->tn_sym); 4567 if (ln->tn_sym->s_scl == EXTERN) 4568 outusg(ln->tn_sym); 4569 } 4570 if (ln->tn_op == INDIR && ln->tn_left->tn_op == PLUS) 4571 /* check the range of array indices */ 4572 check_array_index(ln->tn_left, false); 4573 } 4574 4575 static void 4576 check_expr_call(const tnode_t *tn, const tnode_t *ln, 4577 bool szof, bool vctx, bool cond, bool retval_discarded) 4578 { 4579 lint_assert(ln->tn_op == ADDR); 4580 lint_assert(ln->tn_left->tn_op == NAME); 4581 if (!szof && !is_compiler_builtin(ln->tn_left->tn_sym->s_name)) 4582 outcall(tn, vctx || cond, retval_discarded); 4583 } 4584 4585 static bool 4586 check_expr_op(const tnode_t *tn, op_t op, const tnode_t *ln, 4587 bool szof, bool fcall, bool vctx, bool cond, 4588 bool retval_discarded, bool eqwarn) 4589 { 4590 switch (op) { 4591 case ADDR: 4592 check_expr_addr(ln, szof, fcall); 4593 break; 4594 case LOAD: 4595 check_expr_load(ln); 4596 /* FALLTHROUGH */ 4597 case PUSH: 4598 case INCBEF: 4599 case DECBEF: 4600 case INCAFT: 4601 case DECAFT: 4602 case ADDASS: 4603 case SUBASS: 4604 case MULASS: 4605 case DIVASS: 4606 case MODASS: 4607 case ANDASS: 4608 case ORASS: 4609 case XORASS: 4610 case SHLASS: 4611 case SHRASS: 4612 case REAL: 4613 case IMAG: 4614 check_expr_side_effect(ln, szof); 4615 break; 4616 case ASSIGN: 4617 check_expr_assign(ln, szof); 4618 break; 4619 case CALL: 4620 check_expr_call(tn, ln, szof, vctx, cond, retval_discarded); 4621 break; 4622 case EQ: 4623 if (hflag && eqwarn) 4624 /* operator '==' found where '=' was expected */ 4625 warning(160); 4626 break; 4627 case CON: 4628 case NAME: 4629 case STRING: 4630 return false; 4631 default: 4632 break; 4633 } 4634 return true; 4635 } 4636 4637 /* 4638 * vctx ??? 4639 * cond whether the expression is a condition that 4640 * will be compared with 0 4641 * eqwarn whether the operator '==' might be a 4642 * misspelled '=' 4643 * fcall whether the expression is a function call 4644 * retval_discarded whether the return value of a function call 4645 * is discarded; such calls will be analyzed by 4646 * lint2 in messages 4, 8 and 9 4647 * szof whether the expression is part of a sizeof 4648 * expression, which means that its value is 4649 * discarded since only the type is relevant 4650 */ 4651 void 4652 check_expr_misc(const tnode_t *tn, bool vctx, bool cond, 4653 bool eqwarn, bool fcall, bool retval_discarded, bool szof) 4654 { 4655 4656 if (tn == NULL) 4657 return; 4658 4659 tnode_t *ln = tn->tn_left; 4660 tnode_t *rn = tn->tn_right; 4661 op_t op = tn->tn_op; 4662 const mod_t *mp = &modtab[op]; 4663 4664 if (!check_expr_op(tn, op, ln, 4665 szof, fcall, vctx, cond, retval_discarded, eqwarn)) 4666 return; 4667 4668 bool cvctx = mp->m_value_context; 4669 bool ccond = mp->m_compares_with_zero; 4670 bool eq = mp->m_warn_if_operand_eq && 4671 !ln->tn_parenthesized && 4672 rn != NULL && !rn->tn_parenthesized; 4673 4674 /* 4675 * values of operands of ':' are not used if the type of at least 4676 * one of the operands (for gcc compatibility) is void 4677 * XXX test/value context of QUEST should probably be used as 4678 * context for both operands of COLON 4679 */ 4680 if (op == COLON && tn->tn_type->t_tspec == VOID) 4681 cvctx = ccond = false; 4682 bool discard = op == CVT && tn->tn_type->t_tspec == VOID; 4683 check_expr_misc(ln, cvctx, ccond, eq, op == CALL, discard, szof); 4684 4685 switch (op) { 4686 case PUSH: 4687 if (rn != NULL) 4688 check_expr_misc(rn, false, false, eq, false, false, 4689 szof); 4690 break; 4691 case LOGAND: 4692 case LOGOR: 4693 check_expr_misc(rn, false, true, eq, false, false, szof); 4694 break; 4695 case COLON: 4696 check_expr_misc(rn, cvctx, ccond, eq, false, false, szof); 4697 break; 4698 case COMMA: 4699 check_expr_misc(rn, vctx, cond, false, false, false, szof); 4700 break; 4701 default: 4702 if (mp->m_binary) 4703 check_expr_misc(rn, true, false, eq, false, false, 4704 szof); 4705 break; 4706 } 4707 } 4708 4709 /* 4710 * Return whether the expression can be used for static initialization. 4711 * 4712 * Constant initialization expressions must be constant or an address 4713 * of a static object with an optional offset. In the first case, 4714 * the result is returned in *offsp. In the second case, the static 4715 * object is returned in *symp and the offset in *offsp. 4716 * 4717 * The expression can consist of PLUS, MINUS, ADDR, NAME, STRING and 4718 * CON. Type conversions are allowed if they do not change binary 4719 * representation (including width). 4720 * 4721 * C99 6.6 "Constant expressions" 4722 * C99 6.7.8p4 restricts initializers for static storage duration 4723 */ 4724 bool 4725 constant_addr(const tnode_t *tn, const sym_t **symp, ptrdiff_t *offsp) 4726 { 4727 const sym_t *sym; 4728 ptrdiff_t offs1, offs2; 4729 tspec_t t, ot; 4730 4731 switch (tn->tn_op) { 4732 case MINUS: 4733 if (tn->tn_right->tn_op == CVT) 4734 return constant_addr(tn->tn_right, symp, offsp); 4735 else if (tn->tn_right->tn_op != CON) 4736 return false; 4737 /* FALLTHROUGH */ 4738 case PLUS: 4739 offs1 = offs2 = 0; 4740 if (tn->tn_left->tn_op == CON) { 4741 offs1 = (ptrdiff_t)tn->tn_left->tn_val.u.integer; 4742 if (!constant_addr(tn->tn_right, &sym, &offs2)) 4743 return false; 4744 } else if (tn->tn_right->tn_op == CON) { 4745 offs2 = (ptrdiff_t)tn->tn_right->tn_val.u.integer; 4746 if (tn->tn_op == MINUS) 4747 offs2 = -offs2; 4748 if (!constant_addr(tn->tn_left, &sym, &offs1)) 4749 return false; 4750 } else { 4751 return false; 4752 } 4753 *symp = sym; 4754 *offsp = offs1 + offs2; 4755 return true; 4756 case ADDR: 4757 if (tn->tn_left->tn_op == NAME) { 4758 *symp = tn->tn_left->tn_sym; 4759 *offsp = 0; 4760 return true; 4761 } else { 4762 /* 4763 * If this were the front end of a compiler, we 4764 * would return a label instead of 0, at least if 4765 * 'tn->tn_left->tn_op == STRING'. 4766 */ 4767 *symp = NULL; 4768 *offsp = 0; 4769 return true; 4770 } 4771 case CVT: 4772 t = tn->tn_type->t_tspec; 4773 ot = tn->tn_left->tn_type->t_tspec; 4774 if ((!is_integer(t) && t != PTR) || 4775 (!is_integer(ot) && ot != PTR)) { 4776 return false; 4777 } 4778 #if 0 4779 /* 4780 * consider: 4781 * struct foo { 4782 * unsigned char a; 4783 * } f = { 4784 * (unsigned char)(unsigned long) 4785 * (&(((struct foo *)0)->a)) 4786 * }; 4787 * since psize(unsigned long) != psize(unsigned char), 4788 * this fails. 4789 */ 4790 else if (psize(t) != psize(ot)) 4791 return -1; 4792 #endif 4793 return constant_addr(tn->tn_left, symp, offsp); 4794 default: 4795 return false; 4796 } 4797 } 4798 4799 /* Append s2 to s1, then free s2. */ 4800 strg_t * 4801 cat_strings(strg_t *s1, strg_t *s2) 4802 { 4803 4804 if (s1->st_char != s2->st_char) { 4805 /* cannot concatenate wide and regular string literals */ 4806 error(292); 4807 return s1; 4808 } 4809 4810 size_t len1 = s1->st_len; 4811 size_t len2 = s2->st_len; 4812 size_t chsize = s1->st_char ? sizeof(char) : sizeof(wchar_t); 4813 size_t size1 = len1 * chsize; 4814 size_t size2 = (len2 + 1) * chsize; 4815 s1->st_mem = xrealloc(s1->st_mem, size1 + size2); 4816 memcpy((char *)s1->st_mem + size1, s2->st_mem, size2); 4817 free(s2->st_mem); 4818 4819 s1->st_len = len1 + len2; 4820 free(s2); 4821 4822 return s1; 4823 } 4824 4825 4826 typedef struct stmt_expr { 4827 memory_pool se_mem; 4828 sym_t *se_sym; 4829 struct stmt_expr *se_enclosing; 4830 } stmt_expr; 4831 4832 static stmt_expr *stmt_exprs; 4833 4834 void 4835 begin_statement_expr(void) 4836 { 4837 debug_enter(); 4838 4839 stmt_expr *se = xmalloc(sizeof(*se)); 4840 se->se_mem = expr_save_memory(); 4841 se->se_sym = NULL; 4842 se->se_enclosing = stmt_exprs; 4843 stmt_exprs = se; 4844 } 4845 4846 void 4847 do_statement_expr(tnode_t *tn) 4848 { 4849 block_level--; 4850 mem_block_level--; 4851 stmt_exprs->se_sym = tn != NULL 4852 ? mktempsym(block_dup_type(tn->tn_type)) 4853 : NULL; /* after a syntax error */ 4854 mem_block_level++; 4855 block_level++; 4856 /* '({ ... })' is a GCC extension */ 4857 gnuism(320); 4858 } 4859 4860 tnode_t * 4861 end_statement_expr(void) 4862 { 4863 tnode_t *tn; 4864 4865 stmt_expr *se = stmt_exprs; 4866 if (se->se_sym == NULL) { 4867 tn = NULL; /* after a syntax error */ 4868 goto end; 4869 } 4870 4871 tn = build_name(se->se_sym, false); 4872 (void)expr_save_memory(); /* leak */ 4873 expr_restore_memory(se->se_mem); 4874 stmt_exprs = se->se_enclosing; 4875 free(se); 4876 4877 end: 4878 debug_leave(); 4879 return tn; 4880 } 4881 4882 bool 4883 in_statement_expr(void) 4884 { 4885 return stmt_exprs != NULL; 4886 } 4887
Indexes created Tue Sep 23 07:09:52 GMT 2025