tree.c revision 1.572
1 /* $NetBSD: tree.c,v 1.572 2023/07/15 15:38:03 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 1.572 2023/07/15 15:38:03 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 ANSI C; ... */ 1350 warning(118, "<<="); 1351 1352 if (op != SHLASS && op != SHRASS 1353 && (op == ASSIGN || lt != PTR) 1354 && (lt != rt || (ln->tn_type->t_bitfield && rn->tn_op == CON))) { 1355 rn = convert(op, 0, ln->tn_type, rn); 1356 rt = lt; 1357 } 1358 1359 if (any_query_enabled && rn->tn_op == CVT && rn->tn_cast && 1360 types_compatible(ln->tn_type, rn->tn_type, false, false, NULL) && 1361 is_cast_redundant(rn)) { 1362 /* redundant cast from '%s' to '%s' before assignment */ 1363 query_message(7, 1364 type_name(rn->tn_left->tn_type), type_name(rn->tn_type)); 1365 } 1366 1367 return build_op(op, sys, ln->tn_type, ln, rn); 1368 } 1369 1370 /* 1371 * Create a node for REAL, IMAG 1372 */ 1373 static tnode_t * 1374 build_real_imag(op_t op, bool sys, tnode_t *ln) 1375 { 1376 1377 lint_assert(ln != NULL); 1378 if (ln->tn_op == NAME) { 1379 /* 1380 * This may be too much, but it avoids wrong warnings. 1381 * See d_c99_complex_split.c. 1382 */ 1383 mark_as_used(ln->tn_sym, false, false); 1384 mark_as_set(ln->tn_sym); 1385 } 1386 1387 tspec_t t; 1388 switch (ln->tn_type->t_tspec) { 1389 case LCOMPLEX: 1390 t = LDOUBLE; 1391 break; 1392 case DCOMPLEX: 1393 t = DOUBLE; 1394 break; 1395 case FCOMPLEX: 1396 t = FLOAT; 1397 break; 1398 default: 1399 /* '__%s__' is illegal for type '%s' */ 1400 error(276, op == REAL ? "real" : "imag", 1401 type_name(ln->tn_type)); 1402 return NULL; 1403 } 1404 1405 tnode_t *ntn = build_op(op, sys, gettyp(t), ln, NULL); 1406 ntn->tn_lvalue = true; 1407 return ntn; 1408 } 1409 1410 static bool 1411 is_confusing_precedence(op_t op, op_t lop, bool lparen, op_t rop, bool rparen) 1412 { 1413 1414 if (op == SHL || op == SHR) { 1415 if (!lparen && (lop == PLUS || lop == MINUS)) 1416 return true; 1417 if (!rparen && (rop == PLUS || rop == MINUS)) 1418 return true; 1419 return false; 1420 } 1421 1422 if (op == LOGOR) { 1423 if (!lparen && lop == LOGAND) 1424 return true; 1425 if (!rparen && rop == LOGAND) 1426 return true; 1427 return false; 1428 } 1429 1430 lint_assert(op == BITAND || op == BITXOR || op == BITOR); 1431 if (!lparen && lop != op) { 1432 if (lop == PLUS || lop == MINUS) 1433 return true; 1434 if (lop == BITAND || lop == BITXOR) 1435 return true; 1436 } 1437 if (!rparen && rop != op) { 1438 if (rop == PLUS || rop == MINUS) 1439 return true; 1440 if (rop == BITAND || rop == BITXOR) 1441 return true; 1442 } 1443 return false; 1444 } 1445 1446 /* 1447 * Print a warning if the given node has operands which should be 1448 * parenthesized. 1449 * 1450 * XXX Does not work if an operand is a constant expression. Constant 1451 * expressions are already folded. 1452 */ 1453 static void 1454 check_precedence_confusion(tnode_t *tn) 1455 { 1456 tnode_t *ln, *rn; 1457 1458 if (!hflag) 1459 return; 1460 1461 debug_node(tn); 1462 1463 lint_assert(is_binary(tn)); 1464 for (ln = tn->tn_left; ln->tn_op == CVT; ln = ln->tn_left) 1465 continue; 1466 for (rn = tn->tn_right; rn->tn_op == CVT; rn = rn->tn_left) 1467 continue; 1468 1469 if (is_confusing_precedence(tn->tn_op, 1470 ln->tn_op, ln->tn_parenthesized, 1471 rn->tn_op, rn->tn_parenthesized)) { 1472 /* precedence confusion possible: parenthesize! */ 1473 warning(169); 1474 } 1475 } 1476 1477 /* 1478 * Fold constant nodes, as much as is needed for comparing the value with 0. 1479 */ 1480 static tnode_t * 1481 fold_bool(tnode_t *tn) 1482 { 1483 1484 val_t *v = xcalloc(1, sizeof(*v)); 1485 v->v_tspec = tn->tn_type->t_tspec; 1486 lint_assert(v->v_tspec == INT || (Tflag && v->v_tspec == BOOL)); 1487 1488 bool l = constant_is_nonzero(tn->tn_left); 1489 bool r = is_binary(tn) && constant_is_nonzero(tn->tn_right); 1490 1491 switch (tn->tn_op) { 1492 case NOT: 1493 if (hflag && !suppress_constcond) 1494 /* constant argument to '!' */ 1495 warning(239); 1496 v->u.integer = !l ? 1 : 0; 1497 break; 1498 case LOGAND: 1499 v->u.integer = l && r ? 1 : 0; 1500 break; 1501 case LOGOR: 1502 v->u.integer = l || r ? 1 : 0; 1503 break; 1504 default: 1505 lint_assert(/*CONSTCOND*/false); 1506 } 1507 1508 return build_constant(tn->tn_type, v); 1509 } 1510 1511 static long double 1512 floating_error_value(tspec_t t, long double lv) 1513 { 1514 if (t == FLOAT) 1515 return lv < 0 ? -FLT_MAX : FLT_MAX; 1516 if (t == DOUBLE) 1517 return lv < 0 ? -DBL_MAX : DBL_MAX; 1518 /* 1519 * When NetBSD is cross-built in MKLINT=yes mode on x86_64 for 1520 * sparc64, tools/lint checks this code while building usr.bin/xlint. 1521 * In that situation, lint uses the preprocessor for sparc64, in which 1522 * the type 'long double' is IEEE-754-binary128, affecting the macro 1523 * LDBL_MAX below. The type 'long double', as well as the strtold 1524 * implementation, comes from the host platform x86_64 though, where 1525 * 'long double' consumes 128 bits as well but only uses 80 of them. 1526 * The exponent range of the two 'long double' types is the same, but 1527 * the maximum finite value differs due to the extended precision on 1528 * sparc64. 1529 * 1530 * To properly handle the data types of the target platform, lint 1531 * would have to implement the floating-point types in a 1532 * platform-independent way, which is not worth the effort, given how 1533 * few programs practically use 'long double'. 1534 */ 1535 /* LINTED 248: floating-point constant out of range */ 1536 long double max = LDBL_MAX; 1537 return lv < 0 ? -max : max; 1538 } 1539 1540 static bool 1541 is_floating_overflow(tspec_t t, long double val) 1542 { 1543 if (fpe != 0 || isfinite(val) == 0) 1544 return true; 1545 if (t == FLOAT && (val > FLT_MAX || val < -FLT_MAX)) 1546 return true; 1547 if (t == DOUBLE && (val > DBL_MAX || val < -DBL_MAX)) 1548 return true; 1549 return false; 1550 } 1551 1552 /* 1553 * Fold constant nodes having operands with floating point type. 1554 */ 1555 static tnode_t * 1556 fold_float(tnode_t *tn) 1557 { 1558 1559 fpe = 0; 1560 1561 tspec_t t = tn->tn_type->t_tspec; 1562 1563 val_t *v = xcalloc(1, sizeof(*v)); 1564 v->v_tspec = t; 1565 1566 lint_assert(is_floating(t)); 1567 lint_assert(t == tn->tn_left->tn_type->t_tspec); 1568 lint_assert(!is_binary(tn) || t == tn->tn_right->tn_type->t_tspec); 1569 1570 long double lv = tn->tn_left->tn_val.u.floating; 1571 long double rv = is_binary(tn) ? tn->tn_right->tn_val.u.floating : 0.0; 1572 1573 switch (tn->tn_op) { 1574 case UPLUS: 1575 v->u.floating = lv; 1576 break; 1577 case UMINUS: 1578 v->u.floating = -lv; 1579 break; 1580 case MULT: 1581 v->u.floating = lv * rv; 1582 break; 1583 case DIV: 1584 if (rv == 0.0) { 1585 /* division by 0 */ 1586 error(139); 1587 v->u.floating = floating_error_value(t, lv); 1588 } else { 1589 v->u.floating = lv / rv; 1590 } 1591 break; 1592 case PLUS: 1593 v->u.floating = lv + rv; 1594 break; 1595 case MINUS: 1596 v->u.floating = lv - rv; 1597 break; 1598 case LT: 1599 v->u.integer = lv < rv ? 1 : 0; 1600 break; 1601 case LE: 1602 v->u.integer = lv <= rv ? 1 : 0; 1603 break; 1604 case GE: 1605 v->u.integer = lv >= rv ? 1 : 0; 1606 break; 1607 case GT: 1608 v->u.integer = lv > rv ? 1 : 0; 1609 break; 1610 case EQ: 1611 v->u.integer = lv == rv ? 1 : 0; 1612 break; 1613 case NE: 1614 v->u.integer = lv != rv ? 1 : 0; 1615 break; 1616 default: 1617 lint_assert(/*CONSTCOND*/false); 1618 } 1619 1620 // XXX: Must not access u.floating after setting u.integer. 1621 lint_assert(fpe != 0 || isnan(v->u.floating) == 0); 1622 if (is_complex(v->v_tspec)) { 1623 /* 1624 * Don't warn, as lint doesn't model the imaginary part of 1625 * complex numbers. 1626 */ 1627 fpe = 0; 1628 } else if (is_floating_overflow(t, v->u.floating)) { 1629 /* operator '%s' produces floating point overflow */ 1630 warning(142, op_name(tn->tn_op)); 1631 v->u.floating = floating_error_value(t, v->u.floating); 1632 fpe = 0; 1633 } 1634 1635 return build_constant(tn->tn_type, v); 1636 } 1637 1638 /* 1639 * Create a tree node for a binary operator and its two operands. Also called 1640 * for unary operators; in that case rn is NULL. 1641 * 1642 * Function calls, sizeof and casts are handled elsewhere. 1643 */ 1644 tnode_t * 1645 build_binary(tnode_t *ln, op_t op, bool sys, tnode_t *rn) 1646 { 1647 const mod_t *mp = &modtab[op]; 1648 1649 /* If there was an error in one of the operands, return. */ 1650 if (ln == NULL || (mp->m_binary && rn == NULL)) 1651 return NULL; 1652 1653 /* 1654 * Apply class conversions to the left operand, but only if its 1655 * value is needed or compared with zero. 1656 */ 1657 if (mp->m_value_context || mp->m_compares_with_zero) 1658 ln = cconv(ln); 1659 /* 1660 * The right operand is almost always in a test or value context, 1661 * except if it is a struct or union member. 1662 */ 1663 if (mp->m_binary && op != ARROW && op != POINT) 1664 rn = cconv(rn); 1665 1666 /* 1667 * Print some warnings for comparisons of unsigned values with 1668 * constants lower than or equal to null. This must be done 1669 * before promote() because otherwise unsigned char and unsigned 1670 * short would be promoted to int. Types are also tested to be 1671 * CHAR, which would also become int. 1672 */ 1673 if (mp->m_comparison) 1674 check_integer_comparison(op, ln, rn); 1675 1676 if (mp->m_value_context || mp->m_compares_with_zero) 1677 ln = promote(op, false, ln); 1678 if (mp->m_binary && op != ARROW && op != POINT && 1679 op != ASSIGN && op != RETURN && op != INIT) { 1680 rn = promote(op, false, rn); 1681 } 1682 1683 /* 1684 * If the result of the operation is different for signed or 1685 * unsigned operands and one of the operands is signed only in 1686 * ANSI C, print a warning. 1687 */ 1688 if (mp->m_warn_if_left_unsigned_in_c90 && 1689 ln->tn_op == CON && ln->tn_val.v_unsigned_since_c90) { 1690 /* ANSI C treats constant as unsigned, op '%s' */ 1691 warning(218, op_name(op)); 1692 ln->tn_val.v_unsigned_since_c90 = false; 1693 } 1694 if (mp->m_warn_if_right_unsigned_in_c90 && 1695 rn->tn_op == CON && rn->tn_val.v_unsigned_since_c90) { 1696 /* ANSI C treats constant as unsigned, op '%s' */ 1697 warning(218, op_name(op)); 1698 rn->tn_val.v_unsigned_since_c90 = false; 1699 } 1700 1701 /* Make sure both operands are of the same type */ 1702 if (mp->m_balance_operands || (!allow_c90 && (op == SHL || op == SHR))) 1703 balance(op, &ln, &rn); 1704 1705 /* 1706 * Check types for compatibility with the operation and mutual 1707 * compatibility. Return if there are serious problems. 1708 */ 1709 if (!typeok(op, 0, ln, rn)) 1710 return NULL; 1711 1712 /* And now create the node. */ 1713 tnode_t *ntn; 1714 switch (op) { 1715 case POINT: 1716 case ARROW: 1717 ntn = build_struct_access(op, sys, ln, rn); 1718 break; 1719 case INCAFT: 1720 case DECAFT: 1721 case INCBEF: 1722 case DECBEF: 1723 ntn = build_prepost_incdec(op, sys, ln); 1724 break; 1725 case ADDR: 1726 ntn = build_address(sys, ln, false); 1727 break; 1728 case INDIR: 1729 ntn = build_op(INDIR, sys, ln->tn_type->t_subt, ln, NULL); 1730 break; 1731 case PLUS: 1732 case MINUS: 1733 ntn = build_plus_minus(op, sys, ln, rn); 1734 break; 1735 case SHL: 1736 case SHR: 1737 ntn = build_bit_shift(op, sys, ln, rn); 1738 break; 1739 case COLON: 1740 ntn = build_colon(sys, ln, rn); 1741 break; 1742 case ASSIGN: 1743 case MULASS: 1744 case DIVASS: 1745 case MODASS: 1746 case ADDASS: 1747 case SUBASS: 1748 case SHLASS: 1749 case SHRASS: 1750 case ANDASS: 1751 case XORASS: 1752 case ORASS: 1753 case RETURN: 1754 case INIT: 1755 ntn = build_assignment(op, sys, ln, rn); 1756 break; 1757 case COMMA: 1758 if (any_query_enabled) { 1759 /* comma operator with types '%s' and '%s' */ 1760 query_message(12, 1761 type_name(ln->tn_type), type_name(rn->tn_type)); 1762 } 1763 /* FALLTHROUGH */ 1764 case QUEST: 1765 ntn = build_op(op, sys, rn->tn_type, ln, rn); 1766 break; 1767 case REAL: 1768 case IMAG: 1769 ntn = build_real_imag(op, sys, ln); 1770 break; 1771 default: 1772 lint_assert(mp->m_binary == (rn != NULL)); 1773 type_t *rettp = mp->m_returns_bool 1774 ? gettyp(Tflag ? BOOL : INT) : ln->tn_type; 1775 ntn = build_op(op, sys, rettp, ln, rn); 1776 break; 1777 } 1778 1779 /* Return if an error occurred. */ 1780 if (ntn == NULL) 1781 return NULL; 1782 1783 /* Print a warning if precedence confusion is possible */ 1784 if (mp->m_possible_precedence_confusion) 1785 check_precedence_confusion(ntn); 1786 1787 /* 1788 * Print a warning if one of the operands is in a context where 1789 * it is compared with zero and if this operand is a constant. 1790 */ 1791 if (hflag && !suppress_constcond && 1792 mp->m_compares_with_zero && 1793 (ln->tn_op == CON || 1794 ((mp->m_binary && op != QUEST) && rn->tn_op == CON)) && 1795 /* XXX: rn->tn_system_dependent should be checked as well */ 1796 !ln->tn_system_dependent) { 1797 /* constant in conditional context */ 1798 warning(161); 1799 } 1800 1801 /* Fold if the operator requires it */ 1802 if (mp->m_fold_constant_operands) { 1803 if (ln->tn_op == CON && (!mp->m_binary || rn->tn_op == CON)) { 1804 if (mp->m_compares_with_zero) { 1805 ntn = fold_bool(ntn); 1806 } else if (is_floating(ntn->tn_type->t_tspec)) { 1807 ntn = fold_float(ntn); 1808 } else { 1809 ntn = fold(ntn); 1810 } 1811 } else if (op == QUEST && ln->tn_op == CON) { 1812 ntn = ln->tn_val.u.integer != 0 1813 ? rn->tn_left : rn->tn_right; 1814 } 1815 } 1816 1817 return ntn; 1818 } 1819 1820 tnode_t * 1821 build_unary(op_t op, bool sys, tnode_t *tn) 1822 { 1823 return build_binary(tn, op, sys, NULL); 1824 } 1825 1826 static bool 1827 are_members_compatible(const sym_t *a, const sym_t *b) 1828 { 1829 if (a->u.s_member.sm_offset_in_bits != b->u.s_member.sm_offset_in_bits) 1830 return false; 1831 1832 const type_t *atp = a->s_type; 1833 const type_t *btp = b->s_type; 1834 bool w = false; 1835 if (!types_compatible(atp, btp, false, false, &w) && !w) 1836 return false; 1837 if (a->s_bitfield != b->s_bitfield) 1838 return false; 1839 if (a->s_bitfield) { 1840 if (atp->t_bit_field_width != btp->t_bit_field_width) 1841 return false; 1842 if (atp->t_bit_field_offset != btp->t_bit_field_offset) 1843 return false; 1844 } 1845 return true; 1846 } 1847 1848 /* 1849 * Return whether all struct/union members with the same name have the same 1850 * type and offset. 1851 */ 1852 static bool 1853 all_members_compatible(const sym_t *msym) 1854 { 1855 for (const sym_t *csym = msym; 1856 csym != NULL; csym = csym->s_symtab_next) { 1857 if (!is_member(csym)) 1858 continue; 1859 if (strcmp(msym->s_name, csym->s_name) != 0) 1860 continue; 1861 1862 for (const sym_t *sym = csym->s_symtab_next; 1863 sym != NULL; sym = sym->s_symtab_next) { 1864 if (is_member(sym) 1865 && strcmp(csym->s_name, sym->s_name) == 0 1866 && !are_members_compatible(csym, sym)) 1867 return false; 1868 } 1869 } 1870 return true; 1871 } 1872 1873 sym_t * 1874 find_member(const type_t *tp, const char *name) 1875 { 1876 for (sym_t *mem = tp->t_sou->sou_first_member; 1877 mem != NULL; mem = mem->s_next) { 1878 lint_assert(is_member(mem)); 1879 lint_assert(mem->u.s_member.sm_containing_type == tp->t_sou); 1880 if (strcmp(mem->s_name, name) == 0) 1881 return mem; 1882 } 1883 for (sym_t *mem = tp->t_sou->sou_first_member; 1884 mem != NULL; mem = mem->s_next) { 1885 if (is_struct_or_union(mem->s_type->t_tspec) && 1886 mem->s_name == unnamed) { 1887 sym_t *nested_mem = find_member(mem->s_type, name); 1888 if (nested_mem != NULL) 1889 return nested_mem; 1890 } 1891 } 1892 return NULL; 1893 } 1894 1895 /* 1896 * Remove the member if it was unknown until now, which means 1897 * that no defined struct or union has a member with the same name. 1898 */ 1899 static void 1900 remove_unknown_member(tnode_t *tn, sym_t *msym) 1901 { 1902 /* type '%s' does not have member '%s' */ 1903 error(101, type_name(tn->tn_type), msym->s_name); 1904 rmsym(msym); 1905 msym->s_kind = FMEMBER; 1906 msym->s_scl = STRUCT_MEMBER; 1907 1908 struct_or_union *sou = expr_zero_alloc(sizeof(*sou), 1909 "struct_or_union"); 1910 sou->sou_tag = expr_zero_alloc(sizeof(*sou->sou_tag), "sym"); 1911 sou->sou_tag->s_name = unnamed; 1912 1913 msym->u.s_member.sm_containing_type = sou; 1914 /* 1915 * The member sm_offset_in_bits is not needed here since this 1916 * symbol can only be used for error reporting. 1917 */ 1918 } 1919 1920 /* 1921 * Returns a symbol which has the same name as the msym argument and is a 1922 * member of the struct or union specified by the tn argument. 1923 */ 1924 static sym_t * 1925 struct_or_union_member(tnode_t *tn, op_t op, sym_t *msym) 1926 { 1927 1928 /* Determine the tag type of which msym is expected to be a member. */ 1929 const type_t *tp = NULL; 1930 if (op == POINT && is_struct_or_union(tn->tn_type->t_tspec)) 1931 tp = tn->tn_type; 1932 if (op == ARROW && tn->tn_type->t_tspec == PTR 1933 && is_struct_or_union(tn->tn_type->t_subt->t_tspec)) 1934 tp = tn->tn_type->t_subt; 1935 struct_or_union *sou = tp != NULL ? tp->t_sou : NULL; 1936 1937 /* 1938 * If this struct/union has a member with the name of msym, return it. 1939 */ 1940 if (sou != NULL) { 1941 for (sym_t *sym = msym; 1942 sym != NULL; sym = sym->s_symtab_next) { 1943 if (is_member(sym) && 1944 sym->u.s_member.sm_containing_type == sou && 1945 strcmp(sym->s_name, msym->s_name) == 0) 1946 return sym; 1947 } 1948 } 1949 1950 if (tp != NULL) { 1951 sym_t *nested_mem = find_member(tp, msym->s_name); 1952 if (nested_mem != NULL) 1953 return nested_mem; 1954 } 1955 1956 if (msym->s_scl == NOSCL) { 1957 remove_unknown_member(tn, msym); 1958 return msym; 1959 } 1960 1961 bool eq = all_members_compatible(msym); 1962 1963 /* 1964 * Now handle the case in which the left operand refers really 1965 * to a struct/union, but the right operand is not member of it. 1966 */ 1967 if (sou != NULL) { 1968 if (eq && !allow_c90) { 1969 /* illegal use of member '%s' */ 1970 warning(102, msym->s_name); 1971 } else { 1972 /* illegal use of member '%s' */ 1973 error(102, msym->s_name); 1974 } 1975 return msym; 1976 } 1977 1978 /* 1979 * Now the left operand of ARROW does not point to a struct/union 1980 * or the left operand of POINT is no struct/union. 1981 */ 1982 if (eq) { 1983 if (op == POINT) { 1984 if (!allow_c90) { 1985 /* left operand of '.' must be struct ... */ 1986 warning(103, type_name(tn->tn_type)); 1987 } else { 1988 /* left operand of '.' must be struct ... */ 1989 error(103, type_name(tn->tn_type)); 1990 } 1991 } else { 1992 if (!allow_c90 && tn->tn_type->t_tspec == PTR) { 1993 /* left operand of '->' must be pointer ... */ 1994 warning(104, type_name(tn->tn_type)); 1995 } else { 1996 /* left operand of '->' must be pointer ... */ 1997 error(104, type_name(tn->tn_type)); 1998 } 1999 } 2000 } else { 2001 if (!allow_c90) { 2002 /* non-unique member requires struct/union %s */ 2003 error(105, op == POINT ? "object" : "pointer"); 2004 } else { 2005 /* unacceptable operand of '%s' */ 2006 error(111, op_name(op)); 2007 } 2008 } 2009 2010 return msym; 2011 } 2012 2013 tnode_t * 2014 build_member_access(tnode_t *ln, op_t op, bool sys, sbuf_t *member) 2015 { 2016 sym_t *msym; 2017 2018 if (ln == NULL) 2019 return NULL; 2020 2021 if (op == ARROW) { 2022 /* must do this before struct_or_union_member is called */ 2023 ln = cconv(ln); 2024 } 2025 msym = struct_or_union_member(ln, op, getsym(member)); 2026 return build_binary(ln, op, sys, build_name(msym, false)); 2027 } 2028 2029 /* 2030 * Perform class conversions. 2031 * 2032 * Arrays of type T are converted into pointers to type T. 2033 * Functions are converted to pointers to functions. 2034 * Lvalues are converted to rvalues. 2035 * 2036 * C99 6.3 "Conversions" 2037 * C99 6.3.2 "Other operands" 2038 * C99 6.3.2.1 "Lvalues, arrays, and function designators" 2039 */ 2040 tnode_t * 2041 cconv(tnode_t *tn) 2042 { 2043 /* 2044 * Array-lvalue (array of type T) is converted into rvalue 2045 * (pointer to type T) 2046 */ 2047 if (tn->tn_type->t_tspec == ARRAY) { 2048 if (!tn->tn_lvalue) { 2049 /* XXX print correct operator */ 2050 /* %soperand of '%s' must be lvalue */ 2051 gnuism(114, "", op_name(ADDR)); 2052 } 2053 tn = build_op(ADDR, tn->tn_sys, 2054 expr_derive_type(tn->tn_type->t_subt, PTR), tn, NULL); 2055 } 2056 2057 /* 2058 * Expression of type function (function with return value of type T) 2059 * in rvalue-expression (pointer to function with return value 2060 * of type T) 2061 */ 2062 if (tn->tn_type->t_tspec == FUNC) 2063 tn = build_address(tn->tn_sys, tn, true); 2064 2065 /* lvalue to rvalue */ 2066 if (tn->tn_lvalue) { 2067 type_t *tp = expr_dup_type(tn->tn_type); 2068 /* C99 6.3.2.1p2 sentence 2 says to remove the qualifiers. */ 2069 tp->t_const = tp->t_volatile = false; 2070 tn = build_op(LOAD, tn->tn_sys, tp, tn, NULL); 2071 } 2072 2073 return tn; 2074 } 2075 2076 const tnode_t * 2077 before_conversion(const tnode_t *tn) 2078 { 2079 while (tn->tn_op == CVT && !tn->tn_cast) 2080 tn = tn->tn_left; 2081 return tn; 2082 } 2083 2084 /* 2085 * Most errors required by ANSI C are reported in struct_or_union_member(). 2086 * Here we only check for totally wrong things. 2087 */ 2088 static bool 2089 typeok_point(const tnode_t *ln, const type_t *ltp, tspec_t lt) 2090 { 2091 if (is_struct_or_union(lt)) 2092 return true; 2093 2094 if (lt == FUNC || lt == VOID || ltp->t_bitfield) 2095 goto wrong; 2096 2097 /* 2098 * Some C dialects from before C90 tolerated any lvalue on the 2099 * left-hand side of the '.' operator, allowing things like 2100 * char st[100]; st.st_mtime, assuming that the member 'st_mtime' 2101 * only occurred in a single struct; see typeok_arrow. 2102 */ 2103 if (ln->tn_lvalue) 2104 return true; 2105 2106 wrong: 2107 /* With allow_c90 we already got an error */ 2108 if (!allow_c90) 2109 /* unacceptable operand of '%s' */ 2110 error(111, op_name(POINT)); 2111 2112 return false; 2113 } 2114 2115 static bool 2116 typeok_arrow(tspec_t lt) 2117 { 2118 /* 2119 * C1978 Appendix A 14.1 says: <quote>In fact, any lvalue is allowed 2120 * before '.', and that lvalue is then assumed to have the form of 2121 * the structure of which the name of the right is a member. [...] 2122 * Such constructions are non-portable.</quote> 2123 */ 2124 if (lt == PTR || (!allow_c90 && is_integer(lt))) 2125 return true; 2126 2127 /* With allow_c90 we already got an error */ 2128 if (!allow_c90) 2129 /* unacceptable operand of '%s' */ 2130 error(111, op_name(ARROW)); 2131 return false; 2132 } 2133 2134 static bool 2135 typeok_incdec(op_t op, const tnode_t *tn, const type_t *tp) 2136 { 2137 /* operand has scalar type (checked in typeok) */ 2138 if (!tn->tn_lvalue) { 2139 if (tn->tn_op == CVT && tn->tn_cast && 2140 tn->tn_left->tn_op == LOAD) { 2141 /* a cast does not yield an lvalue */ 2142 error(163); 2143 } 2144 /* %soperand of '%s' must be lvalue */ 2145 error(114, "", op_name(op)); 2146 return false; 2147 } 2148 if (tp->t_const && allow_c90) { 2149 /* %soperand of '%s' must be modifiable lvalue */ 2150 warning(115, "", op_name(op)); 2151 } 2152 return true; 2153 } 2154 2155 static bool 2156 typeok_address(op_t op, const tnode_t *tn, const type_t *tp, tspec_t t) 2157 { 2158 if (t == ARRAY || t == FUNC) { 2159 /* ok, a warning comes later (in build_address()) */ 2160 } else if (!tn->tn_lvalue) { 2161 if (tn->tn_op == CVT && tn->tn_cast && 2162 tn->tn_left->tn_op == LOAD) { 2163 /* a cast does not yield an lvalue */ 2164 error(163); 2165 } 2166 /* %soperand of '%s' must be lvalue */ 2167 error(114, "", op_name(op)); 2168 return false; 2169 } else if (is_scalar(t)) { 2170 if (tp->t_bitfield) { 2171 /* cannot take address of bit-field */ 2172 error(112); 2173 return false; 2174 } 2175 } else if (t != STRUCT && t != UNION) { 2176 /* unacceptable operand of '%s' */ 2177 error(111, op_name(op)); 2178 return false; 2179 } 2180 if (tn->tn_op == NAME && tn->tn_sym->s_register) { 2181 /* cannot take address of register '%s' */ 2182 error(113, tn->tn_sym->s_name); 2183 return false; 2184 } 2185 return true; 2186 } 2187 2188 static bool 2189 typeok_indir(const type_t *tp, tspec_t t) 2190 { 2191 2192 if (t != PTR) { 2193 /* cannot dereference non-pointer type '%s' */ 2194 error(96, type_name(tp)); 2195 return false; 2196 } 2197 return true; 2198 } 2199 2200 static void 2201 warn_incompatible_types(op_t op, 2202 const type_t *ltp, tspec_t lt, 2203 const type_t *rtp, tspec_t rt) 2204 { 2205 bool binary = modtab[op].m_binary; 2206 2207 if (lt == VOID || (binary && rt == VOID)) { 2208 /* void type illegal in expression */ 2209 error(109); 2210 } else if (op == ASSIGN) { 2211 /* cannot assign to '%s' from '%s' */ 2212 error(171, type_name(ltp), type_name(rtp)); 2213 } else if (binary) { 2214 /* operands of '%s' have incompatible types '%s' and '%s' */ 2215 error(107, op_name(op), type_name(ltp), type_name(rtp)); 2216 } else { 2217 lint_assert(rt == NO_TSPEC); 2218 /* operand of '%s' has invalid type '%s' */ 2219 error(108, op_name(op), type_name(ltp)); 2220 } 2221 } 2222 2223 static bool 2224 typeok_plus(op_t op, 2225 const type_t *ltp, tspec_t lt, 2226 const type_t *rtp, tspec_t rt) 2227 { 2228 /* operands have scalar types (checked in typeok) */ 2229 if ((lt == PTR && !is_integer(rt)) || (rt == PTR && !is_integer(lt))) { 2230 warn_incompatible_types(op, ltp, lt, rtp, rt); 2231 return false; 2232 } 2233 return true; 2234 } 2235 2236 static bool 2237 typeok_minus(op_t op, 2238 const type_t *ltp, tspec_t lt, 2239 const type_t *rtp, tspec_t rt) 2240 { 2241 /* operands have scalar types (checked in typeok) */ 2242 if ((lt == PTR && rt != PTR && !is_integer(rt)) || 2243 (lt != PTR && rt == PTR)) { 2244 warn_incompatible_types(op, ltp, lt, rtp, rt); 2245 return false; 2246 } 2247 if (lt == PTR && rt == PTR && 2248 !types_compatible(ltp->t_subt, rtp->t_subt, true, false, NULL)) { 2249 /* illegal pointer subtraction */ 2250 error(116); 2251 } 2252 return true; 2253 } 2254 2255 static void 2256 typeok_shr(op_t op, 2257 const tnode_t *ln, tspec_t lt, 2258 const tnode_t *rn, tspec_t rt) 2259 { 2260 tspec_t olt = before_conversion(ln)->tn_type->t_tspec; 2261 tspec_t ort = before_conversion(rn)->tn_type->t_tspec; 2262 2263 /* operands have integer types (checked in typeok) */ 2264 if (pflag && !is_uinteger(olt)) { 2265 integer_constraints lc = ic_expr(ln); 2266 if (!ic_maybe_signed(ln->tn_type, &lc)) 2267 return; 2268 2269 /* 2270 * The left operand is signed. This means that 2271 * the operation is (possibly) nonportable. 2272 */ 2273 if (ln->tn_op != CON) { 2274 /* bitwise '%s' on signed value possibly nonportable */ 2275 warning(117, op_name(op)); 2276 } else if (ln->tn_val.u.integer < 0) { 2277 /* bitwise '%s' on signed value nonportable */ 2278 warning(120, op_name(op)); 2279 } 2280 } else if (allow_trad && allow_c90 && 2281 !is_uinteger(olt) && is_uinteger(ort)) { 2282 /* The left operand would become unsigned in traditional C. */ 2283 if (hflag && (ln->tn_op != CON || ln->tn_val.u.integer < 0)) { 2284 /* semantics of '%s' change in ANSI C; use ... */ 2285 warning(118, op_name(op)); 2286 } 2287 } else if (allow_trad && allow_c90 && 2288 !is_uinteger(olt) && !is_uinteger(ort) && 2289 portable_rank_cmp(lt, rt) < 0) { 2290 /* 2291 * In traditional C, the left operand would be extended 2292 * (possibly sign-extended) and then shifted. 2293 */ 2294 if (hflag && (ln->tn_op != CON || ln->tn_val.u.integer < 0)) { 2295 /* semantics of '%s' change in ANSI C; use ... */ 2296 warning(118, op_name(op)); 2297 } 2298 } 2299 } 2300 2301 static void 2302 typeok_shl(op_t op, tspec_t lt, tspec_t rt) 2303 { 2304 /* 2305 * C90 does not perform balancing for shift operations, 2306 * but traditional C does. If the width of the right operand 2307 * is greater than the width of the left operand, then in 2308 * traditional C the left operand would be extended to the 2309 * width of the right operand. For SHL this may result in 2310 * different results. 2311 */ 2312 if (portable_rank_cmp(lt, rt) < 0) { 2313 /* 2314 * XXX If both operands are constant, make sure 2315 * that there is really a difference between 2316 * ANSI C and traditional C. 2317 */ 2318 if (hflag && allow_trad && allow_c90) 2319 /* semantics of '%s' change in ANSI C; use ... */ 2320 warning(118, op_name(op)); 2321 } 2322 } 2323 2324 static void 2325 typeok_shift(const type_t *ltp, tspec_t lt, const tnode_t *rn, tspec_t rt) 2326 { 2327 if (rn->tn_op != CON) 2328 return; 2329 2330 if (!is_uinteger(rt) && rn->tn_val.u.integer < 0) { 2331 /* negative shift */ 2332 warning(121); 2333 } else if ((uint64_t)rn->tn_val.u.integer == size_in_bits(lt)) { 2334 /* shift amount %u equals bit-size of '%s' */ 2335 warning(267, (unsigned)rn->tn_val.u.integer, type_name(ltp)); 2336 } else if ((uint64_t)rn->tn_val.u.integer > size_in_bits(lt)) { 2337 /* shift amount %llu is greater than bit-size %llu of '%s' */ 2338 warning(122, (unsigned long long)rn->tn_val.u.integer, 2339 (unsigned long long)size_in_bits(lt), 2340 tspec_name(lt)); 2341 } 2342 } 2343 2344 static bool 2345 is_typeok_eq(const tnode_t *ln, tspec_t lt, const tnode_t *rn, tspec_t rt) 2346 { 2347 if (lt == PTR && is_null_pointer(rn)) 2348 return true; 2349 if (rt == PTR && is_null_pointer(ln)) 2350 return true; 2351 return false; 2352 } 2353 2354 /* 2355 * Called if incompatible pointer types are detected. 2356 * Print an appropriate warning. 2357 */ 2358 static void 2359 warn_incompatible_pointers(op_t op, const type_t *ltp, const type_t *rtp) 2360 { 2361 lint_assert(ltp->t_tspec == PTR); 2362 lint_assert(rtp->t_tspec == PTR); 2363 2364 tspec_t lt = ltp->t_subt->t_tspec; 2365 tspec_t rt = rtp->t_subt->t_tspec; 2366 2367 if (is_struct_or_union(lt) && is_struct_or_union(rt)) { 2368 if (op == RETURN) { 2369 /* illegal structure pointer combination */ 2370 warning(244); 2371 } else { 2372 /* incompatible structure pointers: '%s' '%s' '%s' */ 2373 warning(245, type_name(ltp), 2374 op_name(op), type_name(rtp)); 2375 } 2376 } else { 2377 if (op == RETURN) { 2378 /* illegal combination of '%s' and '%s' */ 2379 warning(184, type_name(ltp), type_name(rtp)); 2380 } else { 2381 /* illegal combination of '%s' and '%s', op '%s' */ 2382 warning(124, 2383 type_name(ltp), type_name(rtp), op_name(op)); 2384 } 2385 } 2386 } 2387 2388 static void 2389 check_pointer_comparison(op_t op, const tnode_t *ln, const tnode_t *rn) 2390 { 2391 type_t *ltp = ln->tn_type, *rtp = rn->tn_type; 2392 tspec_t lst = ltp->t_subt->t_tspec, rst = rtp->t_subt->t_tspec; 2393 2394 if (lst == VOID || rst == VOID) { 2395 /* TODO: C99 behaves like C90 here. */ 2396 if ((!allow_trad && !allow_c99) && 2397 (lst == FUNC || rst == FUNC)) { 2398 /* (void *)0 is already handled in typeok() */ 2399 const char *lsts, *rsts; 2400 *(lst == FUNC ? &lsts : &rsts) = "function pointer"; 2401 *(lst == VOID ? &lsts : &rsts) = "'void *'"; 2402 /* ANSI C forbids comparison of %s with %s */ 2403 warning(274, lsts, rsts); 2404 } 2405 return; 2406 } 2407 2408 if (!types_compatible(ltp->t_subt, rtp->t_subt, true, false, NULL)) { 2409 warn_incompatible_pointers(op, ltp, rtp); 2410 return; 2411 } 2412 2413 if (lst == FUNC && rst == FUNC) { 2414 /* TODO: C99 behaves like C90 here, see C99 6.5.8p2. */ 2415 if ((!allow_trad && !allow_c99) && op != EQ && op != NE) 2416 /* ANSI C forbids ordered comparisons of ... */ 2417 warning(125); 2418 } 2419 } 2420 2421 static bool 2422 typeok_compare(op_t op, 2423 const tnode_t *ln, const type_t *ltp, tspec_t lt, 2424 const tnode_t *rn, const type_t *rtp, tspec_t rt) 2425 { 2426 if (lt == PTR && rt == PTR) { 2427 check_pointer_comparison(op, ln, rn); 2428 return true; 2429 } 2430 2431 if (lt != PTR && rt != PTR) 2432 return true; 2433 2434 if (!is_integer(lt) && !is_integer(rt)) { 2435 warn_incompatible_types(op, ltp, lt, rtp, rt); 2436 return false; 2437 } 2438 2439 const char *lx = lt == PTR ? "pointer" : "integer"; 2440 const char *rx = rt == PTR ? "pointer" : "integer"; 2441 /* illegal combination of %s '%s' and %s '%s', op '%s' */ 2442 warning(123, lx, type_name(ltp), rx, type_name(rtp), op_name(op)); 2443 return true; 2444 } 2445 2446 static bool 2447 typeok_quest(tspec_t lt, const tnode_t *rn) 2448 { 2449 if (!is_scalar(lt)) { 2450 /* first operand of '?' must have scalar type */ 2451 error(170); 2452 return false; 2453 } 2454 lint_assert(before_conversion(rn)->tn_op == COLON); 2455 return true; 2456 } 2457 2458 static void 2459 typeok_colon_pointer(const type_t *ltp, const type_t *rtp) 2460 { 2461 type_t *lstp = ltp->t_subt; 2462 type_t *rstp = rtp->t_subt; 2463 tspec_t lst = lstp->t_tspec; 2464 tspec_t rst = rstp->t_tspec; 2465 2466 if ((lst == VOID && rst == FUNC) || (lst == FUNC && rst == VOID)) { 2467 /* (void *)0 is handled in typeok_colon */ 2468 /* TODO: C99 behaves like C90 here. */ 2469 if (!allow_trad && !allow_c99) 2470 /* ANSI C forbids conversion of %s to %s, op %s */ 2471 warning(305, "function pointer", "'void *'", 2472 op_name(COLON)); 2473 return; 2474 } 2475 2476 if (pointer_types_are_compatible(lstp, rstp, true)) 2477 return; 2478 if (!types_compatible(lstp, rstp, true, false, NULL)) 2479 warn_incompatible_pointers(COLON, ltp, rtp); 2480 } 2481 2482 static bool 2483 typeok_colon(const tnode_t *ln, const type_t *ltp, tspec_t lt, 2484 const tnode_t *rn, const type_t *rtp, tspec_t rt) 2485 { 2486 2487 if (is_arithmetic(lt) && is_arithmetic(rt)) 2488 return true; 2489 if (lt == BOOL && rt == BOOL) 2490 return true; 2491 2492 if (lt == STRUCT && rt == STRUCT && ltp->t_sou == rtp->t_sou) 2493 return true; 2494 if (lt == UNION && rt == UNION && ltp->t_sou == rtp->t_sou) 2495 return true; 2496 2497 if (lt == PTR && is_null_pointer(rn)) 2498 return true; 2499 if (rt == PTR && is_null_pointer(ln)) 2500 return true; 2501 2502 if ((lt == PTR && is_integer(rt)) || (is_integer(lt) && rt == PTR)) { 2503 const char *lx = lt == PTR ? "pointer" : "integer"; 2504 const char *rx = rt == PTR ? "pointer" : "integer"; 2505 /* illegal combination of %s '%s' and %s '%s', op '%s' */ 2506 warning(123, lx, type_name(ltp), 2507 rx, type_name(rtp), op_name(COLON)); 2508 return true; 2509 } 2510 2511 if (lt == VOID || rt == VOID) { 2512 if (lt != VOID || rt != VOID) 2513 /* incompatible types '%s' and '%s' in conditional */ 2514 warning(126, type_name(ltp), type_name(rtp)); 2515 return true; 2516 } 2517 2518 if (lt == PTR && rt == PTR) { 2519 typeok_colon_pointer(ltp, rtp); 2520 return true; 2521 } 2522 2523 /* incompatible types '%s' and '%s' in conditional */ 2524 error(126, type_name(ltp), type_name(rtp)); 2525 return false; 2526 } 2527 2528 /* 2529 * Returns true if the given structure or union has a constant member 2530 * (maybe recursively). 2531 */ 2532 static bool 2533 has_constant_member(const type_t *tp) 2534 { 2535 lint_assert(is_struct_or_union(tp->t_tspec)); 2536 2537 for (sym_t *m = tp->t_sou->sou_first_member; 2538 m != NULL; m = m->s_next) { 2539 const type_t *mtp = m->s_type; 2540 if (mtp->t_const) 2541 return true; 2542 if (is_struct_or_union(mtp->t_tspec) && 2543 has_constant_member(mtp)) 2544 return true; 2545 } 2546 return false; 2547 } 2548 2549 static bool 2550 typeok_assign(op_t op, const tnode_t *ln, const type_t *ltp, tspec_t lt) 2551 { 2552 if (op == RETURN || op == INIT || op == FARG) 2553 return true; 2554 2555 if (!ln->tn_lvalue) { 2556 if (ln->tn_op == CVT && ln->tn_cast && 2557 ln->tn_left->tn_op == LOAD) { 2558 /* a cast does not yield an lvalue */ 2559 error(163); 2560 } 2561 /* %soperand of '%s' must be lvalue */ 2562 error(114, "left ", op_name(op)); 2563 return false; 2564 } else if (ltp->t_const 2565 || (is_struct_or_union(lt) && has_constant_member(ltp))) { 2566 if (allow_c90) 2567 /* %soperand of '%s' must be modifiable lvalue */ 2568 warning(115, "left ", op_name(op)); 2569 } 2570 return true; 2571 } 2572 2573 /* Check the types using the information from modtab[]. */ 2574 static bool 2575 typeok_scalar(op_t op, const mod_t *mp, 2576 const type_t *ltp, tspec_t lt, 2577 const type_t *rtp, tspec_t rt) 2578 { 2579 if (mp->m_takes_bool && lt == BOOL && rt == BOOL) 2580 return true; 2581 if (mp->m_requires_integer) { 2582 if (!is_integer(lt) || (mp->m_binary && !is_integer(rt))) { 2583 warn_incompatible_types(op, ltp, lt, rtp, rt); 2584 return false; 2585 } 2586 } else if (mp->m_requires_integer_or_complex) { 2587 if ((!is_integer(lt) && !is_complex(lt)) || 2588 (mp->m_binary && (!is_integer(rt) && !is_complex(rt)))) { 2589 warn_incompatible_types(op, ltp, lt, rtp, rt); 2590 return false; 2591 } 2592 } else if (mp->m_requires_scalar) { 2593 if (!is_scalar(lt) || (mp->m_binary && !is_scalar(rt))) { 2594 warn_incompatible_types(op, ltp, lt, rtp, rt); 2595 return false; 2596 } 2597 } else if (mp->m_requires_arith) { 2598 if (!is_arithmetic(lt) || 2599 (mp->m_binary && !is_arithmetic(rt))) { 2600 warn_incompatible_types(op, ltp, lt, rtp, rt); 2601 return false; 2602 } 2603 } 2604 return true; 2605 } 2606 2607 static void 2608 check_assign_void_pointer(op_t op, int arg, 2609 tspec_t lt, tspec_t lst, 2610 tspec_t rt, tspec_t rst) 2611 { 2612 2613 if (!(lt == PTR && rt == PTR && (lst == VOID || rst == VOID))) 2614 return; 2615 /* two pointers, at least one pointer to void */ 2616 2617 /* TODO: C99 behaves like C90 here. */ 2618 if (!((!allow_trad && !allow_c99) && (lst == FUNC || rst == FUNC))) 2619 return; 2620 /* comb. of ptr to func and ptr to void */ 2621 2622 const char *lts, *rts; 2623 *(lst == FUNC ? <s : &rts) = "function pointer"; 2624 *(lst == VOID ? <s : &rts) = "'void *'"; 2625 2626 switch (op) { 2627 case INIT: 2628 case RETURN: 2629 /* ANSI C forbids conversion of %s to %s */ 2630 warning(303, rts, lts); 2631 break; 2632 case FARG: 2633 /* ANSI C forbids conversion of %s to %s, arg #%d */ 2634 warning(304, rts, lts, arg); 2635 break; 2636 default: 2637 /* ANSI C forbids conversion of %s to %s, op %s */ 2638 warning(305, rts, lts, op_name(op)); 2639 break; 2640 } 2641 } 2642 2643 static bool 2644 is_direct_function_call(const tnode_t *tn, const char **out_name) 2645 { 2646 2647 if (!(tn->tn_op == CALL && 2648 tn->tn_left->tn_op == ADDR && 2649 tn->tn_left->tn_left->tn_op == NAME)) 2650 return false; 2651 2652 *out_name = tn->tn_left->tn_left->tn_sym->s_name; 2653 return true; 2654 } 2655 2656 static bool 2657 is_unconst_function(const char *name) 2658 { 2659 2660 return strcmp(name, "memchr") == 0 || 2661 strcmp(name, "strchr") == 0 || 2662 strcmp(name, "strpbrk") == 0 || 2663 strcmp(name, "strrchr") == 0 || 2664 strcmp(name, "strstr") == 0; 2665 } 2666 2667 static bool 2668 is_const_char_pointer(const tnode_t *tn) 2669 { 2670 /* 2671 * For traditional reasons, C99 6.4.5p5 defines that string literals 2672 * have type 'char[]'. They are often implicitly converted to 2673 * 'char *', for example when they are passed as function arguments. 2674 * 2675 * C99 6.4.5p6 further defines that modifying a string that is 2676 * constructed from a string literal invokes undefined behavior. 2677 * 2678 * Out of these reasons, string literals are treated as 'effectively 2679 * const' here. 2680 */ 2681 if (tn->tn_op == CVT && 2682 tn->tn_left->tn_op == ADDR && 2683 tn->tn_left->tn_left->tn_op == STRING) 2684 return true; 2685 2686 const type_t *tp = before_conversion(tn)->tn_type; 2687 return tp->t_tspec == PTR && 2688 tp->t_subt->t_tspec == CHAR && 2689 tp->t_subt->t_const; 2690 } 2691 2692 static bool 2693 is_first_arg_const_char_pointer(const tnode_t *tn) 2694 { 2695 const tnode_t *an = tn->tn_right; 2696 if (an == NULL) 2697 return false; 2698 2699 while (an->tn_right != NULL) 2700 an = an->tn_right; 2701 return is_const_char_pointer(an->tn_left); 2702 } 2703 2704 static bool 2705 is_const_pointer(const tnode_t *tn) 2706 { 2707 const type_t *tp = before_conversion(tn)->tn_type; 2708 return tp->t_tspec == PTR && tp->t_subt->t_const; 2709 } 2710 2711 static bool 2712 is_second_arg_const_pointer(const tnode_t *tn) 2713 { 2714 const tnode_t *an = tn->tn_right; 2715 if (an == NULL || an->tn_right == NULL) 2716 return false; 2717 2718 while (an->tn_right->tn_right != NULL) 2719 an = an->tn_right; 2720 return is_const_pointer(an->tn_left); 2721 } 2722 2723 static void 2724 check_unconst_function(const type_t *lstp, const tnode_t *rn) 2725 { 2726 const char *function_name; 2727 2728 if (lstp->t_tspec == CHAR && !lstp->t_const && 2729 is_direct_function_call(rn, &function_name) && 2730 is_unconst_function(function_name) && 2731 is_first_arg_const_char_pointer(rn)) { 2732 /* call to '%s' effectively discards 'const' from argument */ 2733 warning(346, function_name); 2734 } 2735 2736 if (!lstp->t_const && 2737 is_direct_function_call(rn, &function_name) && 2738 strcmp(function_name, "bsearch") == 0 && 2739 is_second_arg_const_pointer(rn)) { 2740 /* call to '%s' effectively discards 'const' from argument */ 2741 warning(346, function_name); 2742 } 2743 } 2744 2745 static bool 2746 check_assign_void_pointer_compat(op_t op, int arg, 2747 const type_t *const ltp, tspec_t const lt, 2748 const type_t *const lstp, tspec_t const lst, 2749 const tnode_t *const rn, 2750 const type_t *const rtp, tspec_t const rt, 2751 const type_t *const rstp, tspec_t const rst) 2752 { 2753 if (!(lt == PTR && rt == PTR && (lst == VOID || rst == VOID || 2754 types_compatible(lstp, rstp, 2755 true, false, NULL)))) 2756 return false; 2757 2758 /* compatible pointer types (qualifiers ignored) */ 2759 if (allow_c90 && 2760 ((!lstp->t_const && rstp->t_const) || 2761 (!lstp->t_volatile && rstp->t_volatile))) { 2762 /* left side has not all qualifiers of right */ 2763 switch (op) { 2764 case INIT: 2765 case RETURN: 2766 /* incompatible pointer types to '%s' and '%s' */ 2767 warning(182, type_name(lstp), type_name(rstp)); 2768 break; 2769 case FARG: 2770 /* converting '%s' to incompatible '%s' ... */ 2771 warning(153, 2772 type_name(rtp), type_name(ltp), arg); 2773 break; 2774 default: 2775 /* operands of '%s' have incompatible pointer ... */ 2776 warning(128, op_name(op), 2777 type_name(lstp), type_name(rstp)); 2778 break; 2779 } 2780 } 2781 2782 if (allow_c90) 2783 check_unconst_function(lstp, rn); 2784 2785 return true; 2786 } 2787 2788 static bool 2789 check_assign_pointer_integer(op_t op, int arg, 2790 const type_t *const ltp, tspec_t const lt, 2791 const type_t *const rtp, tspec_t const rt) 2792 { 2793 2794 if (!((lt == PTR && is_integer(rt)) || (is_integer(lt) && rt == PTR))) 2795 return false; 2796 2797 const char *lx = lt == PTR ? "pointer" : "integer"; 2798 const char *rx = rt == PTR ? "pointer" : "integer"; 2799 2800 switch (op) { 2801 case INIT: 2802 case RETURN: 2803 /* illegal combination of %s '%s' and %s '%s' */ 2804 warning(183, lx, type_name(ltp), rx, type_name(rtp)); 2805 break; 2806 case FARG: 2807 /* illegal combination of %s '%s' and %s '%s', arg #%d */ 2808 warning(154, 2809 lx, type_name(ltp), rx, type_name(rtp), arg); 2810 break; 2811 default: 2812 /* illegal combination of %s '%s' and %s '%s', op '%s' */ 2813 warning(123, 2814 lx, type_name(ltp), rx, type_name(rtp), op_name(op)); 2815 break; 2816 } 2817 return true; 2818 } 2819 2820 static bool 2821 check_assign_pointer(op_t op, int arg, 2822 const type_t *ltp, tspec_t lt, 2823 const type_t *rtp, tspec_t rt) 2824 { 2825 if (!(lt == PTR && rt == PTR)) 2826 return false; 2827 2828 if (op == FARG) 2829 /* converting '%s' to incompatible '%s' for ... */ 2830 warning(153, type_name(rtp), type_name(ltp), arg); 2831 else 2832 warn_incompatible_pointers(op, ltp, rtp); 2833 return true; 2834 } 2835 2836 static void 2837 warn_assign(op_t op, int arg, 2838 const type_t *ltp, tspec_t lt, 2839 const type_t *rtp, tspec_t rt) 2840 { 2841 switch (op) { 2842 case INIT: 2843 /* cannot initialize '%s' from '%s' */ 2844 error(185, type_name(ltp), type_name(rtp)); 2845 break; 2846 case RETURN: 2847 /* function has return type '%s' but returns '%s' */ 2848 error(211, type_name(ltp), type_name(rtp)); 2849 break; 2850 case FARG: 2851 /* passing '%s' to incompatible '%s', arg #%d */ 2852 warning(155, type_name(rtp), type_name(ltp), arg); 2853 break; 2854 default: 2855 warn_incompatible_types(op, ltp, lt, rtp, rt); 2856 break; 2857 } 2858 } 2859 2860 /* 2861 * Checks type compatibility for ASSIGN, INIT, FARG and RETURN 2862 * and prints warnings/errors if necessary. 2863 * Returns whether the types are (almost) compatible. 2864 */ 2865 static bool 2866 check_assign_types_compatible(op_t op, int arg, 2867 const tnode_t *ln, const tnode_t *rn) 2868 { 2869 tspec_t lt, rt, lst = NO_TSPEC, rst = NO_TSPEC; 2870 type_t *ltp, *rtp, *lstp = NULL, *rstp = NULL; 2871 2872 if ((lt = (ltp = ln->tn_type)->t_tspec) == PTR) 2873 lst = (lstp = ltp->t_subt)->t_tspec; 2874 if ((rt = (rtp = rn->tn_type)->t_tspec) == PTR) 2875 rst = (rstp = rtp->t_subt)->t_tspec; 2876 2877 if (lt == BOOL && is_scalar(rt)) /* C99 6.3.1.2 */ 2878 return true; 2879 2880 if (is_arithmetic(lt) && (is_arithmetic(rt) || rt == BOOL)) 2881 return true; 2882 2883 if (is_struct_or_union(lt) && is_struct_or_union(rt)) 2884 /* both are struct or union */ 2885 return ltp->t_sou == rtp->t_sou; 2886 2887 /* a null pointer may be assigned to any pointer */ 2888 if (lt == PTR && is_null_pointer(rn)) { 2889 if (is_integer(rn->tn_type->t_tspec)) 2890 /* implicit conversion from integer 0 to pointer ... */ 2891 query_message(15, type_name(ltp)); 2892 return true; 2893 } 2894 2895 check_assign_void_pointer(op, arg, lt, lst, rt, rst); 2896 2897 if (check_assign_void_pointer_compat(op, arg, 2898 ltp, lt, lstp, lst, rn, rtp, rt, rstp, rst)) 2899 return true; 2900 2901 if (check_assign_pointer_integer(op, arg, ltp, lt, rtp, rt)) 2902 return true; 2903 2904 if (check_assign_pointer(op, arg, ltp, lt, rtp, rt)) 2905 return true; 2906 2907 warn_assign(op, arg, ltp, lt, rtp, rt); 2908 return false; 2909 } 2910 2911 static bool 2912 has_side_effect(const tnode_t *tn) /* NOLINT(misc-no-recursion) */ 2913 { 2914 op_t op = tn->tn_op; 2915 2916 if (modtab[op].m_has_side_effect) 2917 return true; 2918 2919 if (op == CVT && tn->tn_type->t_tspec == VOID) 2920 return has_side_effect(tn->tn_left); 2921 2922 /* XXX: Why not has_side_effect(tn->tn_left) as well? */ 2923 if (op == LOGAND || op == LOGOR) 2924 return has_side_effect(tn->tn_right); 2925 2926 /* XXX: Why not has_side_effect(tn->tn_left) as well? */ 2927 if (op == QUEST) 2928 return has_side_effect(tn->tn_right); 2929 2930 if (op == COLON || op == COMMA) { 2931 return has_side_effect(tn->tn_left) || 2932 has_side_effect(tn->tn_right); 2933 } 2934 2935 return false; 2936 } 2937 2938 static bool 2939 is_void_cast(const tnode_t *tn) 2940 { 2941 2942 return tn->tn_op == CVT && tn->tn_cast && 2943 tn->tn_type->t_tspec == VOID; 2944 } 2945 2946 static bool 2947 is_local_symbol(const tnode_t *tn) 2948 { 2949 2950 return tn->tn_op == LOAD && 2951 tn->tn_left->tn_op == NAME && 2952 tn->tn_left->tn_sym->s_scl == AUTO; 2953 } 2954 2955 static bool 2956 is_int_constant_zero(const tnode_t *tn) 2957 { 2958 2959 return tn->tn_op == CON && 2960 tn->tn_type->t_tspec == INT && 2961 tn->tn_val.u.integer == 0; 2962 } 2963 2964 static void 2965 check_null_effect(const tnode_t *tn) 2966 { 2967 2968 if (hflag && 2969 !has_side_effect(tn) && 2970 !(is_void_cast(tn) && is_local_symbol(tn->tn_left)) && 2971 !(is_void_cast(tn) && is_int_constant_zero(tn->tn_left))) { 2972 /* expression has null effect */ 2973 warning(129); 2974 } 2975 } 2976 2977 /* 2978 * Check the types for specific operators and type combinations. 2979 * 2980 * At this point, the operands already conform to the type requirements of 2981 * the operator, such as being integer, floating or scalar. 2982 */ 2983 static bool 2984 typeok_op(op_t op, int arg, 2985 const tnode_t *ln, const type_t *ltp, tspec_t lt, 2986 const tnode_t *rn, const type_t *rtp, tspec_t rt) 2987 { 2988 switch (op) { 2989 case ARROW: 2990 return typeok_arrow(lt); 2991 case POINT: 2992 return typeok_point(ln, ltp, lt); 2993 case INCBEF: 2994 case DECBEF: 2995 case INCAFT: 2996 case DECAFT: 2997 return typeok_incdec(op, ln, ltp); 2998 case INDIR: 2999 return typeok_indir(ltp, lt); 3000 case ADDR: 3001 return typeok_address(op, ln, ltp, lt); 3002 case PLUS: 3003 return typeok_plus(op, ltp, lt, rtp, rt); 3004 case MINUS: 3005 return typeok_minus(op, ltp, lt, rtp, rt); 3006 case SHL: 3007 typeok_shl(op, lt, rt); 3008 goto shift; 3009 case SHR: 3010 typeok_shr(op, ln, lt, rn, rt); 3011 shift: 3012 typeok_shift(ltp, lt, rn, rt); 3013 break; 3014 case LT: 3015 case LE: 3016 case GT: 3017 case GE: 3018 compare: 3019 return typeok_compare(op, ln, ltp, lt, rn, rtp, rt); 3020 case EQ: 3021 case NE: 3022 if (is_typeok_eq(ln, lt, rn, rt)) 3023 break; 3024 goto compare; 3025 case QUEST: 3026 return typeok_quest(lt, rn); 3027 case COLON: 3028 return typeok_colon(ln, ltp, lt, rn, rtp, rt); 3029 case ASSIGN: 3030 case INIT: 3031 case FARG: 3032 case RETURN: 3033 if (!check_assign_types_compatible(op, arg, ln, rn)) 3034 return false; 3035 goto assign; 3036 case MULASS: 3037 case DIVASS: 3038 case MODASS: 3039 goto assign; 3040 case ADDASS: 3041 case SUBASS: 3042 if ((lt == PTR && !is_integer(rt)) || rt == PTR) { 3043 warn_incompatible_types(op, ltp, lt, rtp, rt); 3044 return false; 3045 } 3046 goto assign; 3047 case SHLASS: 3048 goto assign; 3049 case SHRASS: 3050 if (pflag && !is_uinteger(lt) && 3051 !(!allow_c90 && is_uinteger(rt))) { 3052 /* bitwise '%s' on signed value possibly nonportable */ 3053 warning(117, op_name(op)); 3054 } 3055 goto assign; 3056 case ANDASS: 3057 case XORASS: 3058 case ORASS: 3059 assign: 3060 return typeok_assign(op, ln, ltp, lt); 3061 case COMMA: 3062 if (!modtab[ln->tn_op].m_has_side_effect) 3063 check_null_effect(ln); 3064 break; 3065 default: 3066 break; 3067 } 3068 return true; 3069 } 3070 3071 /* Prints a warning if a strange operator is used on an enum type. */ 3072 static void 3073 check_bad_enum_operation(op_t op, const tnode_t *ln, const tnode_t *rn) 3074 { 3075 3076 if (!eflag) 3077 return; 3078 3079 /* Allow enum in array indices. */ 3080 if (op == PLUS && 3081 ((ln->tn_type->t_is_enum && rn->tn_type->t_tspec == PTR) || 3082 (rn->tn_type->t_is_enum && ln->tn_type->t_tspec == PTR))) { 3083 return; 3084 } 3085 3086 /* dubious operation '%s' on enum */ 3087 warning(241, op_name(op)); 3088 } 3089 3090 /* Prints a warning if an operator is applied to two different enum types. */ 3091 static void 3092 check_enum_type_mismatch(op_t op, int arg, const tnode_t *ln, const tnode_t *rn) 3093 { 3094 const mod_t *mp = &modtab[op]; 3095 3096 if (ln->tn_type->t_enum != rn->tn_type->t_enum) { 3097 switch (op) { 3098 case INIT: 3099 /* enum type mismatch between '%s' and '%s' in ... */ 3100 warning(210, 3101 type_name(ln->tn_type), type_name(rn->tn_type)); 3102 break; 3103 case FARG: 3104 /* function expects '%s', passing '%s' for arg #%d */ 3105 warning(156, 3106 type_name(ln->tn_type), type_name(rn->tn_type), 3107 arg); 3108 break; 3109 case RETURN: 3110 /* function has return type '%s' but returns '%s' */ 3111 warning(211, 3112 type_name(ln->tn_type), type_name(rn->tn_type)); 3113 break; 3114 default: 3115 /* enum type mismatch: '%s' '%s' '%s' */ 3116 warning(130, type_name(ln->tn_type), op_name(op), 3117 type_name(rn->tn_type)); 3118 break; 3119 } 3120 } else if (Pflag && eflag && mp->m_comparison && op != EQ && op != NE) 3121 /* operator '%s' assumes that '%s' is ordered */ 3122 warning(243, op_name(op), type_name(ln->tn_type)); 3123 } 3124 3125 /* Prints a warning if the operands mix between enum and integer. */ 3126 static void 3127 check_enum_int_mismatch(op_t op, int arg, const tnode_t *ln, const tnode_t *rn) 3128 { 3129 3130 if (!eflag) 3131 return; 3132 3133 switch (op) { 3134 case INIT: 3135 /* 3136 * Initialization with 0 is allowed. Otherwise, all implicit 3137 * initializations would need to be warned upon as well. 3138 */ 3139 if (!rn->tn_type->t_is_enum && rn->tn_op == CON && 3140 is_integer(rn->tn_type->t_tspec) && 3141 rn->tn_val.u.integer == 0) { 3142 return; 3143 } 3144 /* initialization of '%s' with '%s' */ 3145 warning(277, type_name(ln->tn_type), type_name(rn->tn_type)); 3146 break; 3147 case FARG: 3148 /* combination of '%s' and '%s', arg #%d */ 3149 warning(278, 3150 type_name(ln->tn_type), type_name(rn->tn_type), arg); 3151 break; 3152 case RETURN: 3153 /* combination of '%s' and '%s' in return */ 3154 warning(279, type_name(ln->tn_type), type_name(rn->tn_type)); 3155 break; 3156 default: 3157 /* combination of '%s' and '%s', op '%s' */ 3158 warning(242, type_name(ln->tn_type), type_name(rn->tn_type), 3159 op_name(op)); 3160 break; 3161 } 3162 } 3163 3164 static void 3165 typeok_enum(op_t op, const mod_t *mp, int arg, 3166 const tnode_t *ln, const type_t *ltp, 3167 const tnode_t *rn, const type_t *rtp) 3168 { 3169 if (mp->m_bad_on_enum && 3170 (ltp->t_is_enum || (mp->m_binary && rtp->t_is_enum))) { 3171 check_bad_enum_operation(op, ln, rn); 3172 } else if (mp->m_valid_on_enum && 3173 (ltp->t_is_enum && rtp != NULL && rtp->t_is_enum)) { 3174 check_enum_type_mismatch(op, arg, ln, rn); 3175 } else if (mp->m_valid_on_enum && 3176 (ltp->t_is_enum || (rtp != NULL && rtp->t_is_enum))) { 3177 check_enum_int_mismatch(op, arg, ln, rn); 3178 } 3179 } 3180 3181 /* Perform most type checks. Return whether the types are ok. */ 3182 bool 3183 typeok(op_t op, int arg, const tnode_t *ln, const tnode_t *rn) 3184 { 3185 3186 const mod_t *mp = &modtab[op]; 3187 3188 type_t *ltp = ln->tn_type; 3189 tspec_t lt = ltp->t_tspec; 3190 3191 type_t *rtp = mp->m_binary ? rn->tn_type : NULL; 3192 tspec_t rt = mp->m_binary ? rtp->t_tspec : NO_TSPEC; 3193 3194 if (Tflag && !typeok_scalar_strict_bool(op, mp, arg, ln, rn)) 3195 return false; 3196 if (!typeok_scalar(op, mp, ltp, lt, rtp, rt)) 3197 return false; 3198 3199 if (!typeok_op(op, arg, ln, ltp, lt, rn, rtp, rt)) 3200 return false; 3201 3202 typeok_enum(op, mp, arg, ln, ltp, rn, rtp); 3203 return true; 3204 } 3205 3206 /* In traditional C, keep unsigned and promote FLOAT to DOUBLE. */ 3207 static tspec_t 3208 promote_trad(tspec_t t) 3209 { 3210 3211 if (t == UCHAR || t == USHORT) 3212 return UINT; 3213 if (t == CHAR || t == SCHAR || t == SHORT) 3214 return INT; 3215 if (t == FLOAT) 3216 return DOUBLE; 3217 if (t == ENUM) 3218 return INT; 3219 return t; 3220 } 3221 3222 /* 3223 * C99 6.3.1.1p2 requires for types with lower rank than int that "If an int 3224 * can represent all the values of the original type, the value is converted 3225 * to an int; otherwise it is converted to an unsigned int", and that "All 3226 * other types are unchanged by the integer promotions". 3227 */ 3228 static tspec_t 3229 promote_c90(const tnode_t *tn, tspec_t t, bool farg) 3230 { 3231 if (tn->tn_type->t_bitfield) { 3232 unsigned int width = tn->tn_type->t_bit_field_width; 3233 unsigned int int_width = size_in_bits(INT); 3234 // XXX: What about _Bool bit-fields, since C99? 3235 if (width < int_width) 3236 return INT; 3237 if (width == int_width) 3238 return is_uinteger(t) ? UINT : INT; 3239 return t; 3240 } 3241 3242 if (t == CHAR || t == SCHAR) 3243 return INT; 3244 if (t == UCHAR) 3245 return size_in_bits(CHAR) < size_in_bits(INT) ? INT : UINT; 3246 if (t == SHORT) 3247 return INT; 3248 if (t == USHORT) 3249 return size_in_bits(SHORT) < size_in_bits(INT) ? INT : UINT; 3250 if (t == ENUM) 3251 return INT; 3252 if (farg && t == FLOAT) 3253 return DOUBLE; 3254 return t; 3255 } 3256 3257 /* 3258 * Performs the "integer promotions" (C99 6.3.1.1p2), which convert small 3259 * integer types to either int or unsigned int. 3260 * 3261 * If allow_c90 is unset or the operand is a function argument with no type 3262 * information (no prototype or variable # of args), converts float to double. 3263 */ 3264 tnode_t * 3265 promote(op_t op, bool farg, tnode_t *tn) 3266 { 3267 3268 tspec_t ot = tn->tn_type->t_tspec; 3269 if (!is_arithmetic(ot)) 3270 return tn; 3271 3272 tspec_t nt = allow_c90 ? promote_c90(tn, ot, farg) : promote_trad(ot); 3273 if (nt == ot) 3274 return tn; 3275 3276 type_t *ntp = expr_dup_type(tn->tn_type); 3277 ntp->t_tspec = nt; 3278 /* 3279 * Keep t_is_enum even though t_tspec gets converted from 3280 * ENUM to INT, so we are later able to check compatibility 3281 * of enum types. 3282 */ 3283 return convert(op, 0, ntp, tn); 3284 } 3285 3286 static void 3287 convert_integer_from_floating(op_t op, const type_t *tp, const tnode_t *tn) 3288 { 3289 3290 if (op == CVT) 3291 /* cast from floating point '%s' to integer '%s' */ 3292 query_message(2, type_name(tn->tn_type), type_name(tp)); 3293 else 3294 /* implicit conversion from floating point '%s' to ... */ 3295 query_message(1, type_name(tn->tn_type), type_name(tp)); 3296 } 3297 3298 static bool 3299 should_warn_about_prototype_conversion(tspec_t nt, 3300 tspec_t ot, const tnode_t *ptn) 3301 { 3302 3303 if (nt == ot) 3304 return false; 3305 3306 if (nt == ENUM && ot == INT) 3307 return false; 3308 3309 if (is_floating(nt) != is_floating(ot) || 3310 portable_rank_cmp(nt, ot) != 0) { 3311 /* representation and/or width change */ 3312 if (!is_integer(ot)) 3313 return true; 3314 /* 3315 * XXX: Investigate whether this rule makes sense; see 3316 * tests/usr.bin/xlint/lint1/platform_long.c. 3317 */ 3318 return portable_rank_cmp(ot, INT) > 0; 3319 } 3320 3321 if (!hflag) 3322 return false; 3323 3324 /* 3325 * If the types differ only in sign and the argument has the same 3326 * representation in both types, print no warning. 3327 */ 3328 if (ptn->tn_op == CON && is_integer(nt) && 3329 signed_type(nt) == signed_type(ot) && 3330 !msb(ptn->tn_val.u.integer, ot)) 3331 return false; 3332 3333 return true; 3334 } 3335 3336 /* 3337 * Warn if a prototype causes a type conversion that is different from what 3338 * would happen to the same argument in the absence of a prototype. This 3339 * check is intended for code that needs to stay compatible with pre-C90 C. 3340 * 3341 * Errors/warnings about illegal type combinations are already printed 3342 * in check_assign_types_compatible(). 3343 */ 3344 static void 3345 check_prototype_conversion(int arg, tspec_t nt, tspec_t ot, type_t *tp, 3346 tnode_t *tn) 3347 { 3348 3349 if (!is_arithmetic(nt) || !is_arithmetic(ot)) 3350 return; 3351 3352 /* 3353 * If the type of the formal parameter is char/short, a warning 3354 * would be useless, because functions declared the old style 3355 * can't expect char/short arguments. 3356 */ 3357 if (nt == CHAR || nt == SCHAR || nt == UCHAR || 3358 nt == SHORT || nt == USHORT) 3359 return; 3360 3361 /* apply the default promotion */ 3362 tnode_t *ptn = promote(NOOP, true, tn); 3363 ot = ptn->tn_type->t_tspec; 3364 3365 if (should_warn_about_prototype_conversion(nt, ot, ptn)) { 3366 /* argument %d is converted from '%s' to '%s' ... */ 3367 warning(259, arg, type_name(tn->tn_type), type_name(tp)); 3368 } 3369 } 3370 3371 /* 3372 * When converting a large integer type to a small integer type, in some 3373 * cases the value of the actual expression is further restricted than the 3374 * type bounds, such as in (expr & 0xFF) or (expr % 100) or (expr >> 24). 3375 */ 3376 static bool 3377 can_represent(const type_t *tp, const tnode_t *tn) 3378 { 3379 3380 debug_step("%s: type '%s'", __func__, type_name(tp)); 3381 debug_node(tn); 3382 3383 uint64_t nmask = value_bits(width_in_bits(tp)); 3384 if (!is_uinteger(tp->t_tspec)) 3385 nmask >>= 1; 3386 3387 integer_constraints c = ic_expr(tn); 3388 if ((~c.bclr & ~nmask) == 0) 3389 return true; 3390 3391 integer_constraints tpc = ic_any(tp); 3392 if (is_uinteger(tp->t_tspec) 3393 ? tpc.umin <= c.umin && tpc.umax >= c.umax 3394 : tpc.smin <= c.smin && tpc.smax >= c.smax) 3395 return true; 3396 3397 return false; 3398 } 3399 3400 static void 3401 convert_integer_from_integer(op_t op, int arg, tspec_t nt, tspec_t ot, 3402 type_t *tp, tnode_t *tn) 3403 { 3404 3405 if (tn->tn_op == CON) 3406 return; 3407 3408 if (op == CVT) 3409 return; 3410 3411 if (Pflag && pflag && aflag > 0 && 3412 portable_rank_cmp(nt, ot) > 0 && 3413 is_uinteger(nt) != is_uinteger(ot)) { 3414 if (op == FARG) { 3415 /* conversion to '%s' may sign-extend ... */ 3416 warning(297, type_name(tp), arg); 3417 } else { 3418 /* conversion to '%s' may sign-extend ... */ 3419 warning(131, type_name(tp)); 3420 } 3421 } 3422 3423 if (Pflag && portable_rank_cmp(nt, ot) > 0 && 3424 (tn->tn_op == PLUS || tn->tn_op == MINUS || tn->tn_op == MULT || 3425 tn->tn_op == SHL)) { 3426 /* suggest cast from '%s' to '%s' on op '%s' to ... */ 3427 warning(324, type_name(gettyp(ot)), type_name(tp), 3428 op_name(tn->tn_op)); 3429 } 3430 3431 if (aflag > 0 && 3432 portable_rank_cmp(nt, ot) < 0 && 3433 (portable_rank_cmp(ot, LONG) >= 0 || aflag > 1) && 3434 // XXX: The portable_rank_cmp above aims at portable mode, 3435 // independent of the current platform, while can_represent acts 3436 // on the actual type sizes from the current platform. This mix 3437 // is inconsistent, but anything else would make the exact 3438 // conditions too complicated to grasp. 3439 !can_represent(tp, tn)) { 3440 if (op == FARG) { 3441 /* conversion from '%s' to '%s' may lose ... */ 3442 warning(298, 3443 type_name(tn->tn_type), type_name(tp), arg); 3444 } else { 3445 /* conversion from '%s' to '%s' may lose accuracy */ 3446 warning(132, 3447 type_name(tn->tn_type), type_name(tp)); 3448 } 3449 } 3450 3451 if (any_query_enabled && is_uinteger(nt) != is_uinteger(ot)) 3452 /* implicit conversion changes sign from '%s' to '%s' */ 3453 query_message(3, type_name(tn->tn_type), type_name(tp)); 3454 } 3455 3456 static void 3457 convert_integer_from_pointer(op_t op, tspec_t nt, type_t *tp, tnode_t *tn) 3458 { 3459 3460 if (tn->tn_op == CON) 3461 return; 3462 if (op != CVT) 3463 return; /* We already got an error. */ 3464 if (portable_rank_cmp(nt, PTR) >= 0) 3465 return; 3466 3467 if (pflag && size_in_bits(nt) >= size_in_bits(PTR)) { 3468 /* conversion of pointer to '%s' may lose bits */ 3469 warning(134, type_name(tp)); 3470 } else { 3471 /* conversion of pointer to '%s' loses bits */ 3472 warning(133, type_name(tp)); 3473 } 3474 } 3475 3476 static bool 3477 struct_starts_with(const type_t *struct_tp, const type_t *member_tp) 3478 { 3479 3480 return struct_tp->t_sou->sou_first_member != NULL && 3481 types_compatible(struct_tp->t_sou->sou_first_member->s_type, 3482 member_tp, true, false, NULL); 3483 } 3484 3485 static bool 3486 is_byte_array(const type_t *tp) 3487 { 3488 3489 return tp->t_tspec == ARRAY && 3490 (tp->t_subt->t_tspec == CHAR || tp->t_subt->t_tspec == UCHAR); 3491 } 3492 3493 static bool 3494 union_contains(const type_t *utp, const type_t *mtp) 3495 { 3496 for (const sym_t *mem = utp->t_sou->sou_first_member; 3497 mem != NULL; mem = mem->s_next) { 3498 if (types_compatible(mem->s_type, mtp, true, false, NULL)) 3499 return true; 3500 } 3501 return false; 3502 } 3503 3504 static bool 3505 should_warn_about_pointer_cast(const type_t *nstp, tspec_t nst, 3506 const type_t *ostp, tspec_t ost) 3507 { 3508 3509 while (nst == ARRAY) 3510 nstp = nstp->t_subt, nst = nstp->t_tspec; 3511 while (ost == ARRAY) 3512 ostp = ostp->t_subt, ost = ostp->t_tspec; 3513 3514 if (nst == STRUCT && ost == STRUCT && 3515 (struct_starts_with(nstp, ostp) || 3516 struct_starts_with(ostp, nstp))) 3517 return false; 3518 3519 if (is_incomplete(nstp) || is_incomplete(ostp)) 3520 return false; 3521 3522 if (nst == CHAR || nst == UCHAR) 3523 return false; /* for the sake of traditional C code */ 3524 if (ost == CHAR || ost == UCHAR) 3525 return false; /* for the sake of traditional C code */ 3526 3527 /* Allow cast between pointers to sockaddr variants. */ 3528 if (nst == STRUCT && ost == STRUCT) { 3529 const sym_t *nmem = nstp->t_sou->sou_first_member; 3530 const sym_t *omem = ostp->t_sou->sou_first_member; 3531 while (nmem != NULL && omem != NULL && 3532 types_compatible(nmem->s_type, omem->s_type, 3533 true, false, NULL)) 3534 nmem = nmem->s_next, omem = omem->s_next; 3535 if (nmem != NULL && is_byte_array(nmem->s_type)) 3536 return false; 3537 if (omem != NULL && is_byte_array(omem->s_type)) 3538 return false; 3539 if (nmem == NULL && omem == NULL) 3540 return false; 3541 } 3542 3543 if (nst == UNION || ost == UNION) { 3544 const type_t *union_tp = nst == UNION ? nstp : ostp; 3545 const type_t *other_tp = nst == UNION ? ostp : nstp; 3546 if (union_contains(union_tp, other_tp)) 3547 return false; 3548 } 3549 3550 if (is_struct_or_union(nst) && is_struct_or_union(ost)) 3551 return nstp->t_sou != ostp->t_sou; 3552 3553 enum rank_kind rk1 = type_properties(nst)->tt_rank_kind; 3554 enum rank_kind rk2 = type_properties(ost)->tt_rank_kind; 3555 if (rk1 != rk2 || rk1 == RK_NONE) 3556 return true; 3557 3558 return portable_rank_cmp(nst, ost) != 0; 3559 } 3560 3561 static void 3562 convert_pointer_from_pointer(type_t *ntp, tnode_t *tn) 3563 { 3564 const type_t *nstp = ntp->t_subt; 3565 const type_t *otp = tn->tn_type; 3566 const type_t *ostp = otp->t_subt; 3567 tspec_t nst = nstp->t_tspec; 3568 tspec_t ost = ostp->t_tspec; 3569 3570 if (nst == VOID || ost == VOID) { 3571 /* TODO: C99 behaves like C90 here. */ 3572 if ((!allow_trad && !allow_c99) && (nst == FUNC || ost == FUNC)) { 3573 const char *nts, *ots; 3574 /* null pointers are already handled in convert() */ 3575 *(nst == FUNC ? &nts : &ots) = "function pointer"; 3576 *(nst == VOID ? &nts : &ots) = "'void *'"; 3577 /* ANSI C forbids conversion of %s to %s */ 3578 warning(303, ots, nts); 3579 } 3580 return; 3581 } 3582 if (nst == FUNC && ost == FUNC) 3583 return; 3584 if (nst == FUNC || ost == FUNC) { 3585 /* converting '%s' to '%s' is questionable */ 3586 warning(229, type_name(otp), type_name(ntp)); 3587 return; 3588 } 3589 3590 if (hflag && alignment_in_bits(nstp) > alignment_in_bits(ostp) && 3591 ost != CHAR && ost != UCHAR && 3592 !is_incomplete(ostp) && 3593 !(nst == UNION && union_contains(nstp, ostp))) { 3594 /* converting '%s' to '%s' increases alignment ... */ 3595 warning(135, type_name(otp), type_name(ntp), 3596 alignment_in_bits(ostp) / CHAR_SIZE, 3597 alignment_in_bits(nstp) / CHAR_SIZE); 3598 } 3599 3600 if (cflag && should_warn_about_pointer_cast(nstp, nst, ostp, ost)) { 3601 /* pointer cast from '%s' to '%s' may be troublesome */ 3602 warning(247, type_name(otp), type_name(ntp)); 3603 } 3604 } 3605 3606 /* 3607 * Insert a conversion operator, which converts the type of the node 3608 * to another given type. 3609 * 3610 * Possible values for 'op': 3611 * CVT a cast-expression 3612 * binary integer promotion for one of the operands, or a usual 3613 * arithmetic conversion 3614 * binary plain or compound assignments to bit-fields 3615 * FARG 'arg' is the number of the argument (used for warnings) 3616 * NOOP several other implicit conversions 3617 * ... 3618 */ 3619 tnode_t * 3620 convert(op_t op, int arg, type_t *tp, tnode_t *tn) 3621 { 3622 tspec_t nt = tp->t_tspec; 3623 tspec_t ot = tn->tn_type->t_tspec; 3624 3625 if (allow_trad && allow_c90 && op == FARG) 3626 check_prototype_conversion(arg, nt, ot, tp, tn); 3627 3628 if (nt == BOOL) { 3629 /* No further checks. */ 3630 3631 } else if (is_integer(nt)) { 3632 if (ot == BOOL) { 3633 /* No further checks. */ 3634 } else if (is_integer(ot)) 3635 convert_integer_from_integer(op, arg, nt, ot, tp, tn); 3636 else if (is_floating(ot)) 3637 convert_integer_from_floating(op, tp, tn); 3638 else if (ot == PTR) 3639 convert_integer_from_pointer(op, nt, tp, tn); 3640 3641 } else if (is_floating(nt)) { 3642 /* No further checks. */ 3643 3644 } else if (nt == PTR) { 3645 if (is_null_pointer(tn)) { 3646 /* a null pointer may be assigned to any pointer. */ 3647 } else if (ot == PTR && op == CVT) 3648 convert_pointer_from_pointer(tp, tn); 3649 } 3650 3651 tnode_t *ntn = expr_alloc_tnode(); 3652 ntn->tn_op = CVT; 3653 ntn->tn_type = tp; 3654 ntn->tn_cast = op == CVT; 3655 ntn->tn_sys |= tn->tn_sys; 3656 ntn->tn_right = NULL; 3657 if (tn->tn_op != CON || nt == VOID) { 3658 ntn->tn_left = tn; 3659 } else { 3660 ntn->tn_op = CON; 3661 convert_constant(op, arg, ntn->tn_type, &ntn->tn_val, 3662 &tn->tn_val); 3663 } 3664 3665 return ntn; 3666 } 3667 3668 static void 3669 convert_constant_floating(op_t op, int arg, tspec_t ot, const type_t *tp, 3670 tspec_t nt, val_t *v, val_t *nv) 3671 { 3672 long double max = 0.0, min = 0.0; 3673 3674 switch (nt) { 3675 case CHAR: 3676 max = TARG_CHAR_MAX; min = TARG_CHAR_MIN; break; 3677 case UCHAR: 3678 max = TARG_UCHAR_MAX; min = 0; break; 3679 case SCHAR: 3680 max = TARG_SCHAR_MAX; min = TARG_SCHAR_MIN; break; 3681 case SHORT: 3682 max = TARG_SHRT_MAX; min = TARG_SHRT_MIN; break; 3683 case USHORT: 3684 max = TARG_USHRT_MAX; min = 0; break; 3685 case ENUM: 3686 case INT: 3687 max = TARG_INT_MAX; min = TARG_INT_MIN; break; 3688 case UINT: 3689 max = TARG_UINT_MAX; min = 0; break; 3690 case LONG: 3691 max = TARG_LONG_MAX; min = TARG_LONG_MIN; break; 3692 case ULONG: 3693 max = TARG_ULONG_MAX; min = 0; break; 3694 case LLONG: 3695 max = LLONG_MAX; min = LLONG_MIN; break; 3696 case ULLONG: 3697 max = ULLONG_MAX; min = 0; break; 3698 case FLOAT: 3699 case FCOMPLEX: 3700 max = FLT_MAX; min = -FLT_MAX; break; 3701 case DOUBLE: 3702 case DCOMPLEX: 3703 max = DBL_MAX; min = -DBL_MAX; break; 3704 case PTR: 3705 /* Already got an error because of float --> ptr */ 3706 case LDOUBLE: 3707 case LCOMPLEX: 3708 /* LINTED 248 */ 3709 max = LDBL_MAX; min = -max; break; 3710 default: 3711 lint_assert(/*CONSTCOND*/false); 3712 } 3713 if (v->u.floating > max || v->u.floating < min) { 3714 lint_assert(nt != LDOUBLE); 3715 if (op == FARG) { 3716 /* conversion of '%s' to '%s' is out of range, ... */ 3717 warning(295, 3718 type_name(gettyp(ot)), type_name(tp), arg); 3719 } else { 3720 /* conversion of '%s' to '%s' is out of range */ 3721 warning(119, type_name(gettyp(ot)), type_name(tp)); 3722 } 3723 v->u.floating = v->u.floating > 0 ? max : min; 3724 } 3725 3726 if (nt == FLOAT || nt == FCOMPLEX) 3727 nv->u.floating = (float)v->u.floating; 3728 else if (nt == DOUBLE || nt == DCOMPLEX) 3729 nv->u.floating = (double)v->u.floating; 3730 else if (nt == LDOUBLE || nt == LCOMPLEX) 3731 nv->u.floating = v->u.floating; 3732 else 3733 nv->u.integer = (int64_t)v->u.floating; 3734 } 3735 3736 static bool 3737 convert_constant_to_floating(tspec_t nt, val_t *nv, 3738 tspec_t ot, const val_t *v) 3739 { 3740 if (nt == FLOAT) { 3741 nv->u.floating = (ot == PTR || is_uinteger(ot)) ? 3742 (float)(uint64_t)v->u.integer : (float)v->u.integer; 3743 } else if (nt == DOUBLE) { 3744 nv->u.floating = (ot == PTR || is_uinteger(ot)) ? 3745 (double)(uint64_t)v->u.integer : (double)v->u.integer; 3746 } else if (nt == LDOUBLE) { 3747 nv->u.floating = (ot == PTR || is_uinteger(ot)) 3748 ? (long double)(uint64_t)v->u.integer 3749 : (long double)v->u.integer; 3750 } else 3751 return false; 3752 return true; 3753 } 3754 3755 /* 3756 * Print a warning if bits which were set are lost due to the conversion. 3757 * This can happen with operator ORASS only. 3758 */ 3759 static void 3760 convert_constant_check_range_bitor(size_t nsz, size_t osz, const val_t *v, 3761 uint64_t xmask, op_t op) 3762 { 3763 if (nsz < osz && (v->u.integer & xmask) != 0) { 3764 /* constant truncated by conversion, op '%s' */ 3765 warning(306, op_name(op)); 3766 } 3767 } 3768 3769 /* 3770 * Print a warning if additional bits are not all 1 3771 * and the most significant bit of the old value is 1, 3772 * or if at least one (but not all) removed bit was 0. 3773 */ 3774 static void 3775 convert_constant_check_range_bitand(size_t nsz, size_t osz, 3776 uint64_t xmask, const val_t *nv, 3777 tspec_t ot, const val_t *v, 3778 const type_t *tp, op_t op) 3779 { 3780 if (nsz > osz && 3781 (nv->u.integer & bit((unsigned int)(osz - 1))) != 0 && 3782 (nv->u.integer & xmask) != xmask) { 3783 /* extra bits set to 0 in conversion of '%s' to '%s', ... */ 3784 warning(309, type_name(gettyp(ot)), 3785 type_name(tp), op_name(op)); 3786 } else if (nsz < osz && 3787 (v->u.integer & xmask) != xmask && 3788 (v->u.integer & xmask) != 0) { 3789 /* constant truncated by conversion, op '%s' */ 3790 warning(306, op_name(op)); 3791 } 3792 } 3793 3794 static void 3795 convert_constant_check_range_signed(op_t op, int arg) 3796 { 3797 if (op == ASSIGN) { 3798 /* assignment of negative constant to unsigned type */ 3799 warning(164); 3800 } else if (op == INIT) { 3801 /* initialization of unsigned with negative constant */ 3802 warning(221); 3803 } else if (op == FARG) { 3804 /* conversion of negative constant to unsigned type, ... */ 3805 warning(296, arg); 3806 } else if (modtab[op].m_comparison) { 3807 /* handled by check_integer_comparison() */ 3808 } else { 3809 /* conversion of negative constant to unsigned type */ 3810 warning(222); 3811 } 3812 } 3813 3814 /* 3815 * Loss of significant bit(s). All truncated bits of unsigned types or all 3816 * truncated bits plus the msb of the target for signed types are considered 3817 * to be significant bits. Loss of significant bits means that at least one 3818 * of the bits was set in an unsigned type or that at least one but not all 3819 * of the bits was set in a signed type. Loss of significant bits means that 3820 * it is not possible, also not with necessary casts, to convert back to the 3821 * original type. An example for a necessary cast is: 3822 * char c; int i; c = 128; 3823 * i = c; ** yields -128 ** 3824 * i = (unsigned char)c; ** yields 128 ** 3825 */ 3826 static void 3827 warn_constant_check_range_truncated(op_t op, int arg, const type_t *tp, 3828 tspec_t ot) 3829 { 3830 if (op == ASSIGN && tp->t_bitfield) 3831 /* precision lost in bit-field assignment */ 3832 warning(166); 3833 else if (op == ASSIGN) 3834 /* constant truncated by assignment */ 3835 warning(165); 3836 else if (op == INIT && tp->t_bitfield) 3837 /* bit-field initializer does not fit */ 3838 warning(180); 3839 else if (op == INIT) 3840 /* initializer does not fit */ 3841 warning(178); 3842 else if (op == CASE) 3843 /* case label affected by conversion */ 3844 warning(196); 3845 else if (op == FARG) 3846 /* conversion of '%s' to '%s' is out of range, arg #%d */ 3847 warning(295, type_name(gettyp(ot)), type_name(tp), arg); 3848 else 3849 /* conversion of '%s' to '%s' is out of range */ 3850 warning(119, type_name(gettyp(ot)), type_name(tp)); 3851 } 3852 3853 static void 3854 warn_constant_check_range_loss(op_t op, int arg, const type_t *tp, 3855 tspec_t ot) 3856 { 3857 if (op == ASSIGN && tp->t_bitfield) 3858 /* precision lost in bit-field assignment */ 3859 warning(166); 3860 else if (op == INIT && tp->t_bitfield) 3861 /* bit-field initializer out of range */ 3862 warning(11); 3863 else if (op == CASE) 3864 /* case label affected by conversion */ 3865 warning(196); 3866 else if (op == FARG) 3867 /* conversion of '%s' to '%s' is out of range, arg #%d */ 3868 warning(295, type_name(gettyp(ot)), type_name(tp), arg); 3869 else 3870 /* conversion of '%s' to '%s' is out of range */ 3871 warning(119, type_name(gettyp(ot)), type_name(tp)); 3872 } 3873 3874 static void 3875 convert_constant_check_range(tspec_t ot, const type_t *tp, tspec_t nt, 3876 op_t op, int arg, const val_t *v, val_t *nv) 3877 { 3878 unsigned int obitsz, nbitsz; 3879 uint64_t xmask, xmsk1; 3880 3881 obitsz = size_in_bits(ot); 3882 nbitsz = tp->t_bitfield ? tp->t_bit_field_width : size_in_bits(nt); 3883 xmask = value_bits(nbitsz) ^ value_bits(obitsz); 3884 xmsk1 = value_bits(nbitsz) ^ value_bits(obitsz - 1); 3885 /* 3886 * For bitwise operations we are not interested in the arithmetic 3887 * value, but in the bits itself. 3888 */ 3889 if (op == ORASS || op == BITOR || op == BITXOR) { 3890 convert_constant_check_range_bitor( 3891 nbitsz, obitsz, v, xmask, op); 3892 } else if (op == ANDASS || op == BITAND) { 3893 convert_constant_check_range_bitand( 3894 nbitsz, obitsz, xmask, nv, ot, v, tp, op); 3895 } else if ((nt != PTR && is_uinteger(nt)) && 3896 (ot != PTR && !is_uinteger(ot)) && 3897 v->u.integer < 0) 3898 convert_constant_check_range_signed(op, arg); 3899 else if (nv->u.integer != v->u.integer && nbitsz <= obitsz && 3900 (v->u.integer & xmask) != 0 && 3901 (is_uinteger(ot) || (v->u.integer & xmsk1) != xmsk1)) 3902 warn_constant_check_range_truncated(op, arg, tp, ot); 3903 else if (nv->u.integer != v->u.integer) 3904 warn_constant_check_range_loss(op, arg, tp, ot); 3905 } 3906 3907 /* 3908 * Converts a typed constant to a constant of another type. 3909 * 3910 * op operator which requires conversion 3911 * arg if op is FARG, # of argument 3912 * tp type to which to convert the constant 3913 * nv new constant 3914 * v old constant 3915 */ 3916 void 3917 convert_constant(op_t op, int arg, const type_t *tp, val_t *nv, val_t *v) 3918 { 3919 /* 3920 * TODO: make 'v' const; the name of this function does not suggest 3921 * that it modifies 'v'. 3922 */ 3923 tspec_t ot = v->v_tspec; 3924 tspec_t nt = nv->v_tspec = tp->t_tspec; 3925 bool range_check = false; 3926 3927 if (nt == BOOL) { /* C99 6.3.1.2 */ 3928 nv->v_unsigned_since_c90 = false; 3929 nv->u.integer = is_nonzero_val(v) ? 1 : 0; 3930 return; 3931 } 3932 3933 if (ot == FLOAT || ot == DOUBLE || ot == LDOUBLE) 3934 convert_constant_floating(op, arg, ot, tp, nt, v, nv); 3935 else if (!convert_constant_to_floating(nt, nv, ot, v)) { 3936 range_check = true; /* Check for lost precision. */ 3937 nv->u.integer = v->u.integer; 3938 } 3939 3940 if (allow_trad && allow_c90 && v->v_unsigned_since_c90 && 3941 (is_floating(nt) || ( 3942 (is_integer(nt) && !is_uinteger(nt) && 3943 portable_rank_cmp(nt, ot) > 0)))) { 3944 /* ANSI C treats constant as unsigned */ 3945 warning(157); 3946 v->v_unsigned_since_c90 = false; 3947 } 3948 3949 if (is_integer(nt)) { 3950 nv->u.integer = convert_integer(nv->u.integer, nt, 3951 tp->t_bitfield ? tp->t_bit_field_width : size_in_bits(nt)); 3952 } 3953 3954 if (range_check && op != CVT) 3955 convert_constant_check_range(ot, tp, nt, op, arg, v, nv); 3956 } 3957 3958 /* 3959 * Create a constant node for sizeof. 3960 */ 3961 tnode_t * 3962 build_sizeof(const type_t *tp) 3963 { 3964 unsigned int size_in_bytes = type_size_in_bits(tp) / CHAR_SIZE; 3965 tnode_t *tn = build_integer_constant(SIZEOF_TSPEC, size_in_bytes); 3966 tn->tn_system_dependent = true; 3967 debug_step("build_sizeof '%s' = %u", type_name(tp), size_in_bytes); 3968 return tn; 3969 } 3970 3971 /* 3972 * Create a constant node for offsetof. 3973 */ 3974 /* ARGSUSED */ /* FIXME: See implementation comments. */ 3975 tnode_t * 3976 build_offsetof(const type_t *tp, const sym_t *sym) 3977 { 3978 3979 if (!is_struct_or_union(tp->t_tspec)) 3980 /* unacceptable operand of '%s' */ 3981 error(111, "offsetof"); 3982 3983 /* FIXME: Don't wrongly use the size of the whole type, use sym. */ 3984 unsigned int offset_in_bytes = type_size_in_bits(tp) / CHAR_SIZE; 3985 tnode_t *tn = build_integer_constant(SIZEOF_TSPEC, offset_in_bytes); 3986 tn->tn_system_dependent = true; 3987 return tn; 3988 } 3989 3990 unsigned int 3991 type_size_in_bits(const type_t *tp) 3992 { 3993 3994 unsigned int elem = 1; 3995 bool flex = false; 3996 lint_assert(tp != NULL); 3997 while (tp->t_tspec == ARRAY) { 3998 flex = true; /* allow c99 flex arrays [] [0] */ 3999 elem *= tp->t_dim; 4000 tp = tp->t_subt; 4001 } 4002 if (elem == 0 && !flex) { 4003 /* cannot take size/alignment of incomplete type */ 4004 error(143); 4005 elem = 1; 4006 } 4007 4008 unsigned int elsz; 4009 switch (tp->t_tspec) { 4010 case VOID: 4011 /* cannot take size/alignment of void */ 4012 error(146); 4013 elsz = 1; 4014 break; 4015 case FUNC: 4016 /* cannot take size/alignment of function type '%s' */ 4017 error(144, type_name(tp)); 4018 elsz = 1; 4019 break; 4020 case STRUCT: 4021 case UNION: 4022 if (is_incomplete(tp)) { 4023 /* cannot take size/alignment of incomplete type */ 4024 error(143); 4025 elsz = 1; 4026 } else { 4027 elsz = tp->t_sou->sou_size_in_bits; 4028 } 4029 break; 4030 case ENUM: 4031 if (is_incomplete(tp)) { 4032 /* cannot take size/alignment of incomplete type */ 4033 warning(143); 4034 } 4035 /* FALLTHROUGH */ 4036 default: 4037 if (tp->t_bitfield) { 4038 /* cannot take size/alignment of bit-field */ 4039 error(145); 4040 } 4041 elsz = size_in_bits(tp->t_tspec); 4042 lint_assert(elsz > 0); 4043 break; 4044 } 4045 4046 return elem * elsz; 4047 } 4048 4049 /* C11 6.5.3.4, GCC */ 4050 tnode_t * 4051 build_alignof(const type_t *tp) 4052 { 4053 if (tp->t_tspec == FUNC) { 4054 /* cannot take size/alignment of function type '%s' */ 4055 error(144, type_name(tp)); 4056 return NULL; 4057 } 4058 if (tp->t_tspec == VOID) { 4059 /* cannot take size/alignment of void */ 4060 error(146); 4061 return NULL; 4062 } 4063 if (is_incomplete(tp)) { 4064 /* cannot take size/alignment of incomplete type */ 4065 error(143); 4066 return NULL; 4067 } 4068 if (tp->t_bitfield) { 4069 /* cannot take size/alignment of bit-field */ 4070 error(145); 4071 return NULL; 4072 } 4073 return build_integer_constant(SIZEOF_TSPEC, 4074 (int64_t)alignment_in_bits(tp) / CHAR_SIZE); 4075 } 4076 4077 static tnode_t * 4078 cast_to_union(tnode_t *otn, type_t *ntp) 4079 { 4080 4081 if (!allow_gcc) { 4082 /* union cast is a GCC extension */ 4083 error(328); 4084 return NULL; 4085 } 4086 4087 for (const sym_t *m = ntp->t_sou->sou_first_member; 4088 m != NULL; m = m->s_next) { 4089 if (types_compatible(m->s_type, otn->tn_type, 4090 false, false, NULL)) { 4091 tnode_t *ntn = expr_alloc_tnode(); 4092 ntn->tn_op = CVT; 4093 ntn->tn_type = ntp; 4094 ntn->tn_cast = true; 4095 ntn->tn_left = otn; 4096 ntn->tn_right = NULL; 4097 return ntn; 4098 } 4099 } 4100 4101 /* type '%s' is not a member of '%s' */ 4102 error(329, type_name(otn->tn_type), type_name(ntp)); 4103 return NULL; 4104 } 4105 4106 /* 4107 * Type casts. 4108 */ 4109 tnode_t * 4110 cast(tnode_t *tn, type_t *tp) 4111 { 4112 4113 if (tn == NULL) 4114 return NULL; 4115 4116 tn = cconv(tn); 4117 4118 lint_assert(tp != NULL); 4119 tspec_t nt = tp->t_tspec; 4120 tspec_t ot = tn->tn_type->t_tspec; 4121 4122 if (nt == VOID) { 4123 /* 4124 * C90 6.3.4, C99 6.5.4p2 and C11 6.5.4p2 allow any type to 4125 * be cast to void. The only other allowed casts are from a 4126 * scalar type to a scalar type. 4127 */ 4128 } else if (nt == UNION) 4129 return cast_to_union(tn, tp); 4130 else if (nt == STRUCT || nt == ARRAY || nt == FUNC) { 4131 /* Casting to a struct is an undocumented GCC extension. */ 4132 if (!(allow_gcc && nt == STRUCT)) 4133 goto invalid_cast; 4134 } else if (is_struct_or_union(ot)) 4135 goto invalid_cast; 4136 else if (ot == VOID) { 4137 /* improper cast of void expression */ 4138 error(148); 4139 return NULL; 4140 } else if (is_integer(nt) && is_scalar(ot)) { 4141 /* ok */ 4142 } else if (is_floating(nt) && is_arithmetic(ot)) { 4143 /* ok */ 4144 } else if (nt == PTR && is_integer(ot)) { 4145 /* ok */ 4146 } else if (nt == PTR && ot == PTR) { 4147 if (!tp->t_subt->t_const && tn->tn_type->t_subt->t_const) { 4148 if (hflag) 4149 /* cast discards 'const' from type '%s' */ 4150 warning(275, type_name(tn->tn_type)); 4151 } 4152 } else 4153 goto invalid_cast; 4154 4155 if (any_query_enabled && types_compatible(tp, tn->tn_type, 4156 false, false, NULL)) { 4157 /* no-op cast from '%s' to '%s' */ 4158 query_message(6, type_name(tn->tn_type), type_name(tp)); 4159 } 4160 4161 tn = convert(CVT, 0, tp, tn); 4162 tn->tn_cast = true; 4163 4164 return tn; 4165 4166 invalid_cast: 4167 /* invalid cast from '%s' to '%s' */ 4168 error(147, type_name(tn->tn_type), type_name(tp)); 4169 return NULL; 4170 } 4171 4172 /* 4173 * Create the node for a function argument. 4174 * All necessary conversions and type checks are done in 4175 * build_function_call because build_function_argument has no 4176 * information about expected argument types. 4177 */ 4178 tnode_t * 4179 build_function_argument(tnode_t *args, tnode_t *arg) 4180 { 4181 /* 4182 * If there was a serious error in the expression for the argument, 4183 * create a dummy argument so the positions of the remaining arguments 4184 * will not change. 4185 */ 4186 if (arg == NULL) 4187 arg = build_integer_constant(INT, 0); 4188 4189 return build_op(PUSH, arg->tn_sys, arg->tn_type, arg, args); 4190 } 4191 4192 /* 4193 * Compare the type of an argument with the corresponding type of a 4194 * prototype parameter. If it is a valid combination, but both types 4195 * are not the same, insert a conversion to convert the argument into 4196 * the type of the parameter. 4197 */ 4198 static tnode_t * 4199 check_prototype_argument( 4200 int n, /* pos of arg */ 4201 type_t *tp, /* expected type (from prototype) */ 4202 tnode_t *tn) /* argument */ 4203 { 4204 tnode_t *ln = xcalloc(1, sizeof(*ln)); 4205 ln->tn_type = expr_unqualified_type(tp); 4206 ln->tn_lvalue = true; 4207 if (typeok(FARG, n, ln, tn)) { 4208 bool dowarn; 4209 if (!types_compatible(tp, tn->tn_type, 4210 true, false, (dowarn = false, &dowarn)) || dowarn) 4211 tn = convert(FARG, n, tp, tn); 4212 } 4213 free(ln); 4214 return tn; 4215 } 4216 4217 /* 4218 * Check types of all function arguments and insert conversions, 4219 * if necessary. 4220 */ 4221 static tnode_t * 4222 check_function_arguments(type_t *ftp, tnode_t *args) 4223 { 4224 /* get # of parameters in the prototype */ 4225 int npar = 0; 4226 for (sym_t *asym = ftp->t_args; asym != NULL; asym = asym->s_next) 4227 npar++; 4228 4229 /* get # of arguments in the function call */ 4230 int narg = 0; 4231 for (tnode_t *arg = args; arg != NULL; arg = arg->tn_right) 4232 narg++; 4233 4234 sym_t *asym = ftp->t_args; 4235 if (ftp->t_proto && npar != narg && !(ftp->t_vararg && npar < narg)) { 4236 /* argument mismatch: %d %s passed, %d expected */ 4237 error(150, narg, narg > 1 ? "arguments" : "argument", npar); 4238 asym = NULL; 4239 } 4240 4241 for (int n = 1; n <= narg; n++) { 4242 4243 /* 4244 * The rightmost argument is at the top of the argument 4245 * subtree. 4246 */ 4247 tnode_t *arg = args; 4248 for (int i = narg; i > n; i--, arg = arg->tn_right) 4249 continue; 4250 4251 /* some things which are always not allowed */ 4252 tspec_t at = arg->tn_left->tn_type->t_tspec; 4253 if (at == VOID) { 4254 /* void expressions may not be arguments, arg #%d */ 4255 error(151, n); 4256 return NULL; 4257 } else if (is_struct_or_union(at) && 4258 is_incomplete(arg->tn_left->tn_type)) { 4259 /* argument cannot have unknown size, arg #%d */ 4260 error(152, n); 4261 return NULL; 4262 } else if (is_integer(at) && 4263 arg->tn_left->tn_type->t_is_enum && 4264 is_incomplete(arg->tn_left->tn_type)) { 4265 /* argument cannot have unknown size, arg #%d */ 4266 warning(152, n); 4267 } 4268 4269 /* class conversions (arg in value context) */ 4270 arg->tn_left = cconv(arg->tn_left); 4271 4272 if (asym != NULL) { 4273 arg->tn_left = check_prototype_argument( 4274 n, asym->s_type, arg->tn_left); 4275 } else 4276 arg->tn_left = promote(NOOP, true, arg->tn_left); 4277 arg->tn_type = arg->tn_left->tn_type; 4278 4279 if (asym != NULL) 4280 asym = asym->s_next; 4281 } 4282 4283 return args; 4284 } 4285 4286 /* 4287 * Create the node for a function call. Also check types of 4288 * function arguments and insert conversions, if necessary. 4289 */ 4290 tnode_t * 4291 build_function_call(tnode_t *func, bool sys, tnode_t *args) 4292 { 4293 4294 if (func == NULL) 4295 return NULL; 4296 4297 op_t fcop = func->tn_op == NAME && func->tn_type->t_tspec == FUNC 4298 ? CALL : ICALL; 4299 4300 check_ctype_function_call(func, args); 4301 4302 /* Turn the function name into a pointer to the function. */ 4303 func = cconv(func); 4304 4305 if (func->tn_type->t_tspec != PTR || 4306 func->tn_type->t_subt->t_tspec != FUNC) { 4307 /* cannot call '%s', must be a function */ 4308 error(149, type_name(func->tn_type)); 4309 return NULL; 4310 } 4311 4312 args = check_function_arguments(func->tn_type->t_subt, args); 4313 4314 return build_op(fcop, sys, func->tn_type->t_subt->t_subt, func, args); 4315 } 4316 4317 /* 4318 * Return the value of an integral constant expression. 4319 * If the expression is not constant or its type is not an integer 4320 * type, an error message is printed. 4321 */ 4322 val_t * 4323 integer_constant(tnode_t *tn, bool required) 4324 { 4325 4326 if (tn != NULL) 4327 tn = cconv(tn); 4328 if (tn != NULL) 4329 tn = promote(NOOP, false, tn); 4330 4331 val_t *v = xcalloc(1, sizeof(*v)); 4332 4333 if (tn == NULL) { 4334 lint_assert(seen_error); 4335 debug_step("constant node is null; returning 1 instead"); 4336 v->v_tspec = INT; 4337 v->u.integer = 1; 4338 return v; 4339 } 4340 4341 v->v_tspec = tn->tn_type->t_tspec; 4342 4343 if (tn->tn_op == CON) { 4344 lint_assert(tn->tn_type->t_tspec == tn->tn_val.v_tspec); 4345 if (is_integer(tn->tn_val.v_tspec)) { 4346 v->v_unsigned_since_c90 = 4347 tn->tn_val.v_unsigned_since_c90; 4348 v->u.integer = tn->tn_val.u.integer; 4349 return v; 4350 } 4351 v->u.integer = (int64_t)tn->tn_val.u.floating; 4352 } else { 4353 v->u.integer = 1; 4354 } 4355 4356 if (required) 4357 /* integral constant expression expected */ 4358 error(55); 4359 else 4360 /* variable array dimension is a C99/GCC extension */ 4361 c99ism(318); 4362 4363 if (!is_integer(v->v_tspec)) 4364 v->v_tspec = INT; 4365 4366 return v; 4367 } 4368 4369 static bool 4370 is_constcond_false(const tnode_t *tn, tspec_t t) 4371 { 4372 return (t == BOOL || t == INT) && 4373 tn->tn_op == CON && tn->tn_val.u.integer == 0; 4374 } 4375 4376 /* 4377 * Perform some tests on expressions which can't be done in build_binary() 4378 * and functions called by build_binary(). These tests must be done here 4379 * because we need some information about the context in which the operations 4380 * are performed. 4381 * After all tests are performed and dofreeblk is true, expr() frees the 4382 * memory which is used for the expression. 4383 */ 4384 void 4385 expr(tnode_t *tn, bool vctx, bool cond, bool dofreeblk, bool is_do_while) 4386 { 4387 4388 if (tn == NULL) { /* in case of errors */ 4389 expr_free_all(); 4390 return; 4391 } 4392 4393 /* expr() is also called in global initializations */ 4394 if (dcs->d_kind != DLK_EXTERN && !is_do_while) 4395 check_statement_reachable(); 4396 4397 check_expr_misc(tn, vctx, cond, !cond, false, false, false); 4398 if (tn->tn_op == ASSIGN && !tn->tn_parenthesized) { 4399 if (hflag && cond) 4400 /* assignment in conditional context */ 4401 warning(159); 4402 } else if (tn->tn_op == CON) { 4403 if (hflag && cond && !suppress_constcond && 4404 !tn->tn_system_dependent && 4405 !(is_do_while && 4406 is_constcond_false(tn, tn->tn_type->t_tspec))) 4407 /* constant in conditional context */ 4408 warning(161); 4409 } 4410 if (!modtab[tn->tn_op].m_has_side_effect) { 4411 /* 4412 * for left operands of COMMA this warning is already 4413 * printed 4414 */ 4415 if (tn->tn_op != COMMA && !vctx && !cond) 4416 check_null_effect(tn); 4417 } 4418 debug_node(tn); 4419 4420 /* free the tree memory */ 4421 if (dofreeblk) 4422 expr_free_all(); 4423 } 4424 4425 /* 4426 * Checks the range of array indices, if possible. 4427 * amper is set if only the address of the element is used. This 4428 * means that the index is allowed to refer to the first element 4429 * after the array. 4430 */ 4431 static void 4432 check_array_index(tnode_t *tn, bool amper) 4433 { 4434 const tnode_t *ln = tn->tn_left; 4435 const tnode_t *rn = tn->tn_right; 4436 4437 /* We can only check constant indices. */ 4438 if (rn->tn_op != CON) 4439 return; 4440 4441 /* Return if the left node does not stem from an array. */ 4442 if (ln->tn_op != ADDR) 4443 return; 4444 if (ln->tn_left->tn_op != STRING && ln->tn_left->tn_op != NAME) 4445 return; 4446 if (ln->tn_left->tn_type->t_tspec != ARRAY) 4447 return; 4448 4449 /* 4450 * For incomplete array types, we can print a warning only if 4451 * the index is negative. 4452 */ 4453 if (is_incomplete(ln->tn_left->tn_type) && rn->tn_val.u.integer >= 0) 4454 return; 4455 4456 /* Get the size of one array element */ 4457 int elsz = length_in_bits(ln->tn_type->t_subt, NULL); 4458 if (elsz == 0) 4459 return; 4460 elsz /= CHAR_SIZE; 4461 4462 /* Change the unit of the index from bytes to element size. */ 4463 int64_t con = is_uinteger(rn->tn_type->t_tspec) 4464 ? (int64_t)((uint64_t)rn->tn_val.u.integer / elsz) 4465 : rn->tn_val.u.integer / elsz; 4466 4467 int dim = ln->tn_left->tn_type->t_dim + (amper ? 1 : 0); 4468 4469 if (!is_uinteger(rn->tn_type->t_tspec) && con < 0) { 4470 /* array subscript cannot be negative: %ld */ 4471 warning(167, (long)con); 4472 } else if (dim > 0 && (uint64_t)con >= (uint64_t)dim) { 4473 /* array subscript cannot be > %d: %ld */ 4474 warning(168, dim - 1, (long)con); 4475 } 4476 } 4477 4478 static void 4479 check_expr_addr(const tnode_t *ln, bool szof, bool fcall) 4480 { 4481 /* XXX: Taking warn_about_unreachable into account here feels wrong. */ 4482 if (ln->tn_op == NAME && (reached || !warn_about_unreachable)) { 4483 if (!szof) 4484 mark_as_set(ln->tn_sym); 4485 mark_as_used(ln->tn_sym, fcall, szof); 4486 } 4487 if (ln->tn_op == INDIR && ln->tn_left->tn_op == PLUS) 4488 /* check the range of array indices */ 4489 check_array_index(ln->tn_left, true); 4490 } 4491 4492 static void 4493 check_expr_load(const tnode_t *ln) 4494 { 4495 if (ln->tn_op == INDIR && ln->tn_left->tn_op == PLUS) 4496 /* check the range of array indices */ 4497 check_array_index(ln->tn_left, false); 4498 } 4499 4500 /* 4501 * If there is an asm statement in one of the compound statements around, 4502 * there may be other side effects, so don't warn. 4503 */ 4504 static bool 4505 is_asm_around(void) 4506 { 4507 for (decl_level *dl = dcs; dl != NULL; dl = dl->d_enclosing) 4508 if (dl->d_asm) 4509 return true; 4510 return false; 4511 } 4512 4513 static void 4514 check_expr_side_effect(const tnode_t *ln, bool szof) 4515 { 4516 4517 /* XXX: Taking warn_about_unreachable into account here feels wrong. */ 4518 if (ln->tn_op == NAME && (reached || !warn_about_unreachable)) { 4519 scl_t sc = ln->tn_sym->s_scl; 4520 if (sc != EXTERN && sc != STATIC && 4521 !ln->tn_sym->s_set && !szof && !is_asm_around()) { 4522 /* '%s' may be used before set */ 4523 warning(158, ln->tn_sym->s_name); 4524 mark_as_set(ln->tn_sym); 4525 } 4526 mark_as_used(ln->tn_sym, false, false); 4527 } 4528 } 4529 4530 static void 4531 check_expr_assign(const tnode_t *ln, bool szof) 4532 { 4533 /* XXX: Taking warn_about_unreachable into account here feels wrong. */ 4534 if (ln->tn_op == NAME && !szof && (reached || !warn_about_unreachable)) { 4535 mark_as_set(ln->tn_sym); 4536 if (ln->tn_sym->s_scl == EXTERN) 4537 outusg(ln->tn_sym); 4538 } 4539 if (ln->tn_op == INDIR && ln->tn_left->tn_op == PLUS) 4540 /* check the range of array indices */ 4541 check_array_index(ln->tn_left, false); 4542 } 4543 4544 static void 4545 check_expr_call(const tnode_t *tn, const tnode_t *ln, 4546 bool szof, bool vctx, bool cond, bool retval_discarded) 4547 { 4548 lint_assert(ln->tn_op == ADDR); 4549 lint_assert(ln->tn_left->tn_op == NAME); 4550 if (!szof && !is_compiler_builtin(ln->tn_left->tn_sym->s_name)) 4551 outcall(tn, vctx || cond, retval_discarded); 4552 } 4553 4554 static bool 4555 check_expr_op(const tnode_t *tn, op_t op, const tnode_t *ln, 4556 bool szof, bool fcall, bool vctx, bool cond, 4557 bool retval_discarded, bool eqwarn) 4558 { 4559 switch (op) { 4560 case ADDR: 4561 check_expr_addr(ln, szof, fcall); 4562 break; 4563 case LOAD: 4564 check_expr_load(ln); 4565 /* FALLTHROUGH */ 4566 case PUSH: 4567 case INCBEF: 4568 case DECBEF: 4569 case INCAFT: 4570 case DECAFT: 4571 case ADDASS: 4572 case SUBASS: 4573 case MULASS: 4574 case DIVASS: 4575 case MODASS: 4576 case ANDASS: 4577 case ORASS: 4578 case XORASS: 4579 case SHLASS: 4580 case SHRASS: 4581 case REAL: 4582 case IMAG: 4583 check_expr_side_effect(ln, szof); 4584 break; 4585 case ASSIGN: 4586 check_expr_assign(ln, szof); 4587 break; 4588 case CALL: 4589 check_expr_call(tn, ln, szof, vctx, cond, retval_discarded); 4590 break; 4591 case EQ: 4592 if (hflag && eqwarn) 4593 /* operator '==' found where '=' was expected */ 4594 warning(160); 4595 break; 4596 case CON: 4597 case NAME: 4598 case STRING: 4599 return false; 4600 default: 4601 break; 4602 } 4603 return true; 4604 } 4605 4606 /* 4607 * vctx ??? 4608 * cond whether the expression is a condition that 4609 * will be compared with 0 4610 * eqwarn whether the operator '==' might be a 4611 * misspelled '=' 4612 * fcall whether the expression is a function call 4613 * retval_discarded whether the return value of a function call 4614 * is discarded; such calls will be analyzed by 4615 * lint2 in messages 4, 8 and 9 4616 * szof whether the expression is part of a sizeof 4617 * expression, which means that its value is 4618 * discarded since only the type is relevant 4619 */ 4620 void 4621 check_expr_misc(const tnode_t *tn, bool vctx, bool cond, 4622 bool eqwarn, bool fcall, bool retval_discarded, bool szof) 4623 { 4624 4625 if (tn == NULL) 4626 return; 4627 4628 tnode_t *ln = tn->tn_left; 4629 tnode_t *rn = tn->tn_right; 4630 op_t op = tn->tn_op; 4631 const mod_t *mp = &modtab[op]; 4632 4633 if (!check_expr_op(tn, op, ln, 4634 szof, fcall, vctx, cond, retval_discarded, eqwarn)) 4635 return; 4636 4637 bool cvctx = mp->m_value_context; 4638 bool ccond = mp->m_compares_with_zero; 4639 bool eq = mp->m_warn_if_operand_eq && 4640 !ln->tn_parenthesized && 4641 rn != NULL && !rn->tn_parenthesized; 4642 4643 /* 4644 * values of operands of ':' are not used if the type of at least 4645 * one of the operands (for gcc compatibility) is void 4646 * XXX test/value context of QUEST should probably be used as 4647 * context for both operands of COLON 4648 */ 4649 if (op == COLON && tn->tn_type->t_tspec == VOID) 4650 cvctx = ccond = false; 4651 bool discard = op == CVT && tn->tn_type->t_tspec == VOID; 4652 check_expr_misc(ln, cvctx, ccond, eq, op == CALL, discard, szof); 4653 4654 switch (op) { 4655 case PUSH: 4656 if (rn != NULL) 4657 check_expr_misc(rn, false, false, eq, false, false, 4658 szof); 4659 break; 4660 case LOGAND: 4661 case LOGOR: 4662 check_expr_misc(rn, false, true, eq, false, false, szof); 4663 break; 4664 case COLON: 4665 check_expr_misc(rn, cvctx, ccond, eq, false, false, szof); 4666 break; 4667 case COMMA: 4668 check_expr_misc(rn, vctx, cond, false, false, false, szof); 4669 break; 4670 default: 4671 if (mp->m_binary) 4672 check_expr_misc(rn, true, false, eq, false, false, 4673 szof); 4674 break; 4675 } 4676 } 4677 4678 /* 4679 * Return whether the expression can be used for static initialization. 4680 * 4681 * Constant initialization expressions must be constant or an address 4682 * of a static object with an optional offset. In the first case, 4683 * the result is returned in *offsp. In the second case, the static 4684 * object is returned in *symp and the offset in *offsp. 4685 * 4686 * The expression can consist of PLUS, MINUS, ADDR, NAME, STRING and 4687 * CON. Type conversions are allowed if they do not change binary 4688 * representation (including width). 4689 * 4690 * C99 6.6 "Constant expressions" 4691 * C99 6.7.8p4 restricts initializers for static storage duration 4692 */ 4693 bool 4694 constant_addr(const tnode_t *tn, const sym_t **symp, ptrdiff_t *offsp) 4695 { 4696 const sym_t *sym; 4697 ptrdiff_t offs1, offs2; 4698 tspec_t t, ot; 4699 4700 switch (tn->tn_op) { 4701 case MINUS: 4702 if (tn->tn_right->tn_op == CVT) 4703 return constant_addr(tn->tn_right, symp, offsp); 4704 else if (tn->tn_right->tn_op != CON) 4705 return false; 4706 /* FALLTHROUGH */ 4707 case PLUS: 4708 offs1 = offs2 = 0; 4709 if (tn->tn_left->tn_op == CON) { 4710 offs1 = (ptrdiff_t)tn->tn_left->tn_val.u.integer; 4711 if (!constant_addr(tn->tn_right, &sym, &offs2)) 4712 return false; 4713 } else if (tn->tn_right->tn_op == CON) { 4714 offs2 = (ptrdiff_t)tn->tn_right->tn_val.u.integer; 4715 if (tn->tn_op == MINUS) 4716 offs2 = -offs2; 4717 if (!constant_addr(tn->tn_left, &sym, &offs1)) 4718 return false; 4719 } else { 4720 return false; 4721 } 4722 *symp = sym; 4723 *offsp = offs1 + offs2; 4724 return true; 4725 case ADDR: 4726 if (tn->tn_left->tn_op == NAME) { 4727 *symp = tn->tn_left->tn_sym; 4728 *offsp = 0; 4729 return true; 4730 } else { 4731 /* 4732 * If this were the front end of a compiler, we 4733 * would return a label instead of 0, at least if 4734 * 'tn->tn_left->tn_op == STRING'. 4735 */ 4736 *symp = NULL; 4737 *offsp = 0; 4738 return true; 4739 } 4740 case CVT: 4741 t = tn->tn_type->t_tspec; 4742 ot = tn->tn_left->tn_type->t_tspec; 4743 if ((!is_integer(t) && t != PTR) || 4744 (!is_integer(ot) && ot != PTR)) { 4745 return false; 4746 } 4747 #if 0 4748 /* 4749 * consider: 4750 * struct foo { 4751 * unsigned char a; 4752 * } f = { 4753 * (unsigned char)(unsigned long) 4754 * (&(((struct foo *)0)->a)) 4755 * }; 4756 * since psize(unsigned long) != psize(unsigned char), 4757 * this fails. 4758 */ 4759 else if (psize(t) != psize(ot)) 4760 return -1; 4761 #endif 4762 return constant_addr(tn->tn_left, symp, offsp); 4763 default: 4764 return false; 4765 } 4766 } 4767 4768 /* Append s2 to s1, then free s2. */ 4769 strg_t * 4770 cat_strings(strg_t *s1, strg_t *s2) 4771 { 4772 4773 if (s1->st_char != s2->st_char) { 4774 /* cannot concatenate wide and regular string literals */ 4775 error(292); 4776 return s1; 4777 } 4778 4779 size_t len1 = s1->st_len; 4780 size_t len2 = s2->st_len; 4781 size_t chsize = s1->st_char ? sizeof(char) : sizeof(wchar_t); 4782 size_t size1 = len1 * chsize; 4783 size_t size2 = (len2 + 1) * chsize; 4784 s1->st_mem = xrealloc(s1->st_mem, size1 + size2); 4785 memcpy((char *)s1->st_mem + size1, s2->st_mem, size2); 4786 free(s2->st_mem); 4787 4788 s1->st_len = len1 + len2; 4789 free(s2); 4790 4791 return s1; 4792 } 4793 4794 4795 typedef struct stmt_expr { 4796 memory_pool se_mem; 4797 sym_t *se_sym; 4798 struct stmt_expr *se_enclosing; 4799 } stmt_expr; 4800 4801 static stmt_expr *stmt_exprs; 4802 4803 void 4804 begin_statement_expr(void) 4805 { 4806 debug_enter(); 4807 4808 stmt_expr *se = xmalloc(sizeof(*se)); 4809 se->se_mem = expr_save_memory(); 4810 se->se_sym = NULL; 4811 se->se_enclosing = stmt_exprs; 4812 stmt_exprs = se; 4813 } 4814 4815 void 4816 do_statement_expr(tnode_t *tn) 4817 { 4818 block_level--; 4819 mem_block_level--; 4820 stmt_exprs->se_sym = tn != NULL 4821 ? mktempsym(block_dup_type(tn->tn_type)) 4822 : NULL; /* after a syntax error */ 4823 mem_block_level++; 4824 block_level++; 4825 /* '({ ... })' is a GCC extension */ 4826 gnuism(320); 4827 } 4828 4829 tnode_t * 4830 end_statement_expr(void) 4831 { 4832 tnode_t *tn; 4833 4834 stmt_expr *se = stmt_exprs; 4835 if (se->se_sym == NULL) { 4836 tn = NULL; /* after a syntax error */ 4837 goto end; 4838 } 4839 4840 tn = build_name(se->se_sym, false); 4841 (void)expr_save_memory(); /* leak */ 4842 expr_restore_memory(se->se_mem); 4843 stmt_exprs = se->se_enclosing; 4844 free(se); 4845 4846 end: 4847 debug_leave(); 4848 return tn; 4849 } 4850 4851 bool 4852 in_statement_expr(void) 4853 { 4854 return stmt_exprs != NULL; 4855 } 4856
Indexes created Tue Sep 23 01:09:51 GMT 2025