tree.c revision 1.570
1 /* $NetBSD: tree.c,v 1.570 2023/07/15 14:50:47 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 1.570 2023/07/15 14:50:47 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 if (strcmp(mem->s_name, name) == 0) 1879 return mem; 1880 } 1881 for (sym_t *mem = tp->t_sou->sou_first_member; 1882 mem != NULL; mem = mem->s_next) { 1883 if (is_struct_or_union(mem->s_type->t_tspec) && 1884 mem->s_name == unnamed) { 1885 sym_t *nested_mem = find_member(mem->s_type, name); 1886 if (nested_mem != NULL) 1887 return nested_mem; 1888 } 1889 } 1890 return NULL; 1891 } 1892 1893 /* 1894 * Remove the member if it was unknown until now, which means 1895 * that no defined struct or union has a member with the same name. 1896 */ 1897 static void 1898 remove_unknown_member(tnode_t *tn, sym_t *msym) 1899 { 1900 /* type '%s' does not have member '%s' */ 1901 error(101, type_name(tn->tn_type), msym->s_name); 1902 rmsym(msym); 1903 msym->s_kind = FMEMBER; 1904 msym->s_scl = STRUCT_MEMBER; 1905 1906 struct_or_union *sou = expr_zero_alloc(sizeof(*sou), 1907 "struct_or_union"); 1908 sou->sou_tag = expr_zero_alloc(sizeof(*sou->sou_tag), "sym"); 1909 sou->sou_tag->s_name = unnamed; 1910 1911 msym->u.s_member.sm_containing_type = sou; 1912 /* 1913 * The member sm_offset_in_bits is not needed here since this 1914 * symbol can only be used for error reporting. 1915 */ 1916 } 1917 1918 /* 1919 * Returns a symbol which has the same name as the msym argument and is a 1920 * member of the struct or union specified by the tn argument. 1921 */ 1922 static sym_t * 1923 struct_or_union_member(tnode_t *tn, op_t op, sym_t *msym) 1924 { 1925 1926 if (msym->s_scl == NOSCL) { 1927 remove_unknown_member(tn, msym); 1928 return msym; 1929 } 1930 1931 /* Determine the tag type of which msym is expected to be a member. */ 1932 const type_t *tp = NULL; 1933 if (op == POINT && is_struct_or_union(tn->tn_type->t_tspec)) 1934 tp = tn->tn_type; 1935 if (op == ARROW && tn->tn_type->t_tspec == PTR 1936 && is_struct_or_union(tn->tn_type->t_subt->t_tspec)) 1937 tp = tn->tn_type->t_subt; 1938 struct_or_union *sou = tp != NULL ? tp->t_sou : NULL; 1939 1940 /* 1941 * If this struct/union has a member with the name of msym, return it. 1942 */ 1943 if (sou != NULL) { 1944 for (sym_t *sym = msym; 1945 sym != NULL; sym = sym->s_symtab_next) { 1946 if (is_member(sym) && 1947 sym->u.s_member.sm_containing_type == sou && 1948 strcmp(sym->s_name, msym->s_name) == 0) 1949 return sym; 1950 } 1951 } 1952 1953 if (tp != NULL) { 1954 sym_t *nested_mem = find_member(tp, msym->s_name); 1955 if (nested_mem != NULL) 1956 return nested_mem; 1957 } 1958 1959 bool eq = all_members_compatible(msym); 1960 1961 /* 1962 * Now handle the case in which the left operand refers really 1963 * to a struct/union, but the right operand is not member of it. 1964 */ 1965 if (sou != NULL) { 1966 if (eq && !allow_c90) { 1967 /* illegal use of member '%s' */ 1968 warning(102, msym->s_name); 1969 } else { 1970 /* illegal use of member '%s' */ 1971 error(102, msym->s_name); 1972 } 1973 return msym; 1974 } 1975 1976 /* 1977 * Now the left operand of ARROW does not point to a struct/union 1978 * or the left operand of POINT is no struct/union. 1979 */ 1980 if (eq) { 1981 if (op == POINT) { 1982 if (!allow_c90) { 1983 /* left operand of '.' must be struct ... */ 1984 warning(103, type_name(tn->tn_type)); 1985 } else { 1986 /* left operand of '.' must be struct ... */ 1987 error(103, type_name(tn->tn_type)); 1988 } 1989 } else { 1990 if (!allow_c90 && tn->tn_type->t_tspec == PTR) { 1991 /* left operand of '->' must be pointer ... */ 1992 warning(104, type_name(tn->tn_type)); 1993 } else { 1994 /* left operand of '->' must be pointer ... */ 1995 error(104, type_name(tn->tn_type)); 1996 } 1997 } 1998 } else { 1999 if (!allow_c90) { 2000 /* non-unique member requires struct/union %s */ 2001 error(105, op == POINT ? "object" : "pointer"); 2002 } else { 2003 /* unacceptable operand of '%s' */ 2004 error(111, op_name(op)); 2005 } 2006 } 2007 2008 return msym; 2009 } 2010 2011 tnode_t * 2012 build_member_access(tnode_t *ln, op_t op, bool sys, sbuf_t *member) 2013 { 2014 sym_t *msym; 2015 2016 if (ln == NULL) 2017 return NULL; 2018 2019 if (op == ARROW) { 2020 /* must do this before struct_or_union_member is called */ 2021 ln = cconv(ln); 2022 } 2023 msym = struct_or_union_member(ln, op, getsym(member)); 2024 return build_binary(ln, op, sys, build_name(msym, false)); 2025 } 2026 2027 /* 2028 * Perform class conversions. 2029 * 2030 * Arrays of type T are converted into pointers to type T. 2031 * Functions are converted to pointers to functions. 2032 * Lvalues are converted to rvalues. 2033 * 2034 * C99 6.3 "Conversions" 2035 * C99 6.3.2 "Other operands" 2036 * C99 6.3.2.1 "Lvalues, arrays, and function designators" 2037 */ 2038 tnode_t * 2039 cconv(tnode_t *tn) 2040 { 2041 /* 2042 * Array-lvalue (array of type T) is converted into rvalue 2043 * (pointer to type T) 2044 */ 2045 if (tn->tn_type->t_tspec == ARRAY) { 2046 if (!tn->tn_lvalue) { 2047 /* XXX print correct operator */ 2048 /* %soperand of '%s' must be lvalue */ 2049 gnuism(114, "", op_name(ADDR)); 2050 } 2051 tn = build_op(ADDR, tn->tn_sys, 2052 expr_derive_type(tn->tn_type->t_subt, PTR), tn, NULL); 2053 } 2054 2055 /* 2056 * Expression of type function (function with return value of type T) 2057 * in rvalue-expression (pointer to function with return value 2058 * of type T) 2059 */ 2060 if (tn->tn_type->t_tspec == FUNC) 2061 tn = build_address(tn->tn_sys, tn, true); 2062 2063 /* lvalue to rvalue */ 2064 if (tn->tn_lvalue) { 2065 type_t *tp = expr_dup_type(tn->tn_type); 2066 /* C99 6.3.2.1p2 sentence 2 says to remove the qualifiers. */ 2067 tp->t_const = tp->t_volatile = false; 2068 tn = build_op(LOAD, tn->tn_sys, tp, tn, NULL); 2069 } 2070 2071 return tn; 2072 } 2073 2074 const tnode_t * 2075 before_conversion(const tnode_t *tn) 2076 { 2077 while (tn->tn_op == CVT && !tn->tn_cast) 2078 tn = tn->tn_left; 2079 return tn; 2080 } 2081 2082 /* 2083 * Most errors required by ANSI C are reported in struct_or_union_member(). 2084 * Here we only check for totally wrong things. 2085 */ 2086 static bool 2087 typeok_point(const tnode_t *ln, const type_t *ltp, tspec_t lt) 2088 { 2089 if (is_struct_or_union(lt)) 2090 return true; 2091 2092 if (lt == FUNC || lt == VOID || ltp->t_bitfield) 2093 goto wrong; 2094 2095 /* 2096 * Some C dialects from before C90 tolerated any lvalue on the 2097 * left-hand side of the '.' operator, allowing things like 2098 * char st[100]; st.st_mtime, assuming that the member 'st_mtime' 2099 * only occurred in a single struct; see typeok_arrow. 2100 */ 2101 if (ln->tn_lvalue) 2102 return true; 2103 2104 wrong: 2105 /* With allow_c90 we already got an error */ 2106 if (!allow_c90) 2107 /* unacceptable operand of '%s' */ 2108 error(111, op_name(POINT)); 2109 2110 return false; 2111 } 2112 2113 static bool 2114 typeok_arrow(tspec_t lt) 2115 { 2116 /* 2117 * C1978 Appendix A 14.1 says: <quote>In fact, any lvalue is allowed 2118 * before '.', and that lvalue is then assumed to have the form of 2119 * the structure of which the name of the right is a member. [...] 2120 * Such constructions are non-portable.</quote> 2121 */ 2122 if (lt == PTR || (!allow_c90 && is_integer(lt))) 2123 return true; 2124 2125 /* With allow_c90 we already got an error */ 2126 if (!allow_c90) 2127 /* unacceptable operand of '%s' */ 2128 error(111, op_name(ARROW)); 2129 return false; 2130 } 2131 2132 static bool 2133 typeok_incdec(op_t op, const tnode_t *tn, const type_t *tp) 2134 { 2135 /* operand has scalar type (checked in typeok) */ 2136 if (!tn->tn_lvalue) { 2137 if (tn->tn_op == CVT && tn->tn_cast && 2138 tn->tn_left->tn_op == LOAD) { 2139 /* a cast does not yield an lvalue */ 2140 error(163); 2141 } 2142 /* %soperand of '%s' must be lvalue */ 2143 error(114, "", op_name(op)); 2144 return false; 2145 } 2146 if (tp->t_const && allow_c90) { 2147 /* %soperand of '%s' must be modifiable lvalue */ 2148 warning(115, "", op_name(op)); 2149 } 2150 return true; 2151 } 2152 2153 static bool 2154 typeok_address(op_t op, const tnode_t *tn, const type_t *tp, tspec_t t) 2155 { 2156 if (t == ARRAY || t == FUNC) { 2157 /* ok, a warning comes later (in build_address()) */ 2158 } else if (!tn->tn_lvalue) { 2159 if (tn->tn_op == CVT && tn->tn_cast && 2160 tn->tn_left->tn_op == LOAD) { 2161 /* a cast does not yield an lvalue */ 2162 error(163); 2163 } 2164 /* %soperand of '%s' must be lvalue */ 2165 error(114, "", op_name(op)); 2166 return false; 2167 } else if (is_scalar(t)) { 2168 if (tp->t_bitfield) { 2169 /* cannot take address of bit-field */ 2170 error(112); 2171 return false; 2172 } 2173 } else if (t != STRUCT && t != UNION) { 2174 /* unacceptable operand of '%s' */ 2175 error(111, op_name(op)); 2176 return false; 2177 } 2178 if (tn->tn_op == NAME && tn->tn_sym->s_register) { 2179 /* cannot take address of register '%s' */ 2180 error(113, tn->tn_sym->s_name); 2181 return false; 2182 } 2183 return true; 2184 } 2185 2186 static bool 2187 typeok_indir(const type_t *tp, tspec_t t) 2188 { 2189 2190 if (t != PTR) { 2191 /* cannot dereference non-pointer type '%s' */ 2192 error(96, type_name(tp)); 2193 return false; 2194 } 2195 return true; 2196 } 2197 2198 static void 2199 warn_incompatible_types(op_t op, 2200 const type_t *ltp, tspec_t lt, 2201 const type_t *rtp, tspec_t rt) 2202 { 2203 bool binary = modtab[op].m_binary; 2204 2205 if (lt == VOID || (binary && rt == VOID)) { 2206 /* void type illegal in expression */ 2207 error(109); 2208 } else if (op == ASSIGN) { 2209 /* cannot assign to '%s' from '%s' */ 2210 error(171, type_name(ltp), type_name(rtp)); 2211 } else if (binary) { 2212 /* operands of '%s' have incompatible types '%s' and '%s' */ 2213 error(107, op_name(op), type_name(ltp), type_name(rtp)); 2214 } else { 2215 lint_assert(rt == NO_TSPEC); 2216 /* operand of '%s' has invalid type '%s' */ 2217 error(108, op_name(op), type_name(ltp)); 2218 } 2219 } 2220 2221 static bool 2222 typeok_plus(op_t op, 2223 const type_t *ltp, tspec_t lt, 2224 const type_t *rtp, tspec_t rt) 2225 { 2226 /* operands have scalar types (checked in typeok) */ 2227 if ((lt == PTR && !is_integer(rt)) || (rt == PTR && !is_integer(lt))) { 2228 warn_incompatible_types(op, ltp, lt, rtp, rt); 2229 return false; 2230 } 2231 return true; 2232 } 2233 2234 static bool 2235 typeok_minus(op_t op, 2236 const type_t *ltp, tspec_t lt, 2237 const type_t *rtp, tspec_t rt) 2238 { 2239 /* operands have scalar types (checked in typeok) */ 2240 if ((lt == PTR && rt != PTR && !is_integer(rt)) || 2241 (lt != PTR && rt == PTR)) { 2242 warn_incompatible_types(op, ltp, lt, rtp, rt); 2243 return false; 2244 } 2245 if (lt == PTR && rt == PTR && 2246 !types_compatible(ltp->t_subt, rtp->t_subt, true, false, NULL)) { 2247 /* illegal pointer subtraction */ 2248 error(116); 2249 } 2250 return true; 2251 } 2252 2253 static void 2254 typeok_shr(op_t op, 2255 const tnode_t *ln, tspec_t lt, 2256 const tnode_t *rn, tspec_t rt) 2257 { 2258 tspec_t olt = before_conversion(ln)->tn_type->t_tspec; 2259 tspec_t ort = before_conversion(rn)->tn_type->t_tspec; 2260 2261 /* operands have integer types (checked in typeok) */ 2262 if (pflag && !is_uinteger(olt)) { 2263 integer_constraints lc = ic_expr(ln); 2264 if (!ic_maybe_signed(ln->tn_type, &lc)) 2265 return; 2266 2267 /* 2268 * The left operand is signed. This means that 2269 * the operation is (possibly) nonportable. 2270 */ 2271 if (ln->tn_op != CON) { 2272 /* bitwise '%s' on signed value possibly nonportable */ 2273 warning(117, op_name(op)); 2274 } else if (ln->tn_val.u.integer < 0) { 2275 /* bitwise '%s' on signed value nonportable */ 2276 warning(120, op_name(op)); 2277 } 2278 } else if (allow_trad && allow_c90 && 2279 !is_uinteger(olt) && is_uinteger(ort)) { 2280 /* The left operand would become unsigned in traditional C. */ 2281 if (hflag && (ln->tn_op != CON || ln->tn_val.u.integer < 0)) { 2282 /* semantics of '%s' change in ANSI C; use ... */ 2283 warning(118, op_name(op)); 2284 } 2285 } else if (allow_trad && allow_c90 && 2286 !is_uinteger(olt) && !is_uinteger(ort) && 2287 portable_rank_cmp(lt, rt) < 0) { 2288 /* 2289 * In traditional C, the left operand would be extended 2290 * (possibly sign-extended) and then shifted. 2291 */ 2292 if (hflag && (ln->tn_op != CON || ln->tn_val.u.integer < 0)) { 2293 /* semantics of '%s' change in ANSI C; use ... */ 2294 warning(118, op_name(op)); 2295 } 2296 } 2297 } 2298 2299 static void 2300 typeok_shl(op_t op, tspec_t lt, tspec_t rt) 2301 { 2302 /* 2303 * C90 does not perform balancing for shift operations, 2304 * but traditional C does. If the width of the right operand 2305 * is greater than the width of the left operand, then in 2306 * traditional C the left operand would be extended to the 2307 * width of the right operand. For SHL this may result in 2308 * different results. 2309 */ 2310 if (portable_rank_cmp(lt, rt) < 0) { 2311 /* 2312 * XXX If both operands are constant, make sure 2313 * that there is really a difference between 2314 * ANSI C and traditional C. 2315 */ 2316 if (hflag && allow_trad && allow_c90) 2317 /* semantics of '%s' change in ANSI C; use ... */ 2318 warning(118, op_name(op)); 2319 } 2320 } 2321 2322 static void 2323 typeok_shift(const type_t *ltp, tspec_t lt, const tnode_t *rn, tspec_t rt) 2324 { 2325 if (rn->tn_op != CON) 2326 return; 2327 2328 if (!is_uinteger(rt) && rn->tn_val.u.integer < 0) { 2329 /* negative shift */ 2330 warning(121); 2331 } else if ((uint64_t)rn->tn_val.u.integer == size_in_bits(lt)) { 2332 /* shift amount %u equals bit-size of '%s' */ 2333 warning(267, (unsigned)rn->tn_val.u.integer, type_name(ltp)); 2334 } else if ((uint64_t)rn->tn_val.u.integer > size_in_bits(lt)) { 2335 /* shift amount %llu is greater than bit-size %llu of '%s' */ 2336 warning(122, (unsigned long long)rn->tn_val.u.integer, 2337 (unsigned long long)size_in_bits(lt), 2338 tspec_name(lt)); 2339 } 2340 } 2341 2342 static bool 2343 is_typeok_eq(const tnode_t *ln, tspec_t lt, const tnode_t *rn, tspec_t rt) 2344 { 2345 if (lt == PTR && is_null_pointer(rn)) 2346 return true; 2347 if (rt == PTR && is_null_pointer(ln)) 2348 return true; 2349 return false; 2350 } 2351 2352 /* 2353 * Called if incompatible pointer types are detected. 2354 * Print an appropriate warning. 2355 */ 2356 static void 2357 warn_incompatible_pointers(op_t op, const type_t *ltp, const type_t *rtp) 2358 { 2359 lint_assert(ltp->t_tspec == PTR); 2360 lint_assert(rtp->t_tspec == PTR); 2361 2362 tspec_t lt = ltp->t_subt->t_tspec; 2363 tspec_t rt = rtp->t_subt->t_tspec; 2364 2365 if (is_struct_or_union(lt) && is_struct_or_union(rt)) { 2366 if (op == RETURN) { 2367 /* illegal structure pointer combination */ 2368 warning(244); 2369 } else { 2370 /* incompatible structure pointers: '%s' '%s' '%s' */ 2371 warning(245, type_name(ltp), 2372 op_name(op), type_name(rtp)); 2373 } 2374 } else { 2375 if (op == RETURN) { 2376 /* illegal combination of '%s' and '%s' */ 2377 warning(184, type_name(ltp), type_name(rtp)); 2378 } else { 2379 /* illegal combination of '%s' and '%s', op '%s' */ 2380 warning(124, 2381 type_name(ltp), type_name(rtp), op_name(op)); 2382 } 2383 } 2384 } 2385 2386 static void 2387 check_pointer_comparison(op_t op, const tnode_t *ln, const tnode_t *rn) 2388 { 2389 type_t *ltp = ln->tn_type, *rtp = rn->tn_type; 2390 tspec_t lst = ltp->t_subt->t_tspec, rst = rtp->t_subt->t_tspec; 2391 2392 if (lst == VOID || rst == VOID) { 2393 /* TODO: C99 behaves like C90 here. */ 2394 if ((!allow_trad && !allow_c99) && 2395 (lst == FUNC || rst == FUNC)) { 2396 /* (void *)0 is already handled in typeok() */ 2397 const char *lsts, *rsts; 2398 *(lst == FUNC ? &lsts : &rsts) = "function pointer"; 2399 *(lst == VOID ? &lsts : &rsts) = "'void *'"; 2400 /* ANSI C forbids comparison of %s with %s */ 2401 warning(274, lsts, rsts); 2402 } 2403 return; 2404 } 2405 2406 if (!types_compatible(ltp->t_subt, rtp->t_subt, true, false, NULL)) { 2407 warn_incompatible_pointers(op, ltp, rtp); 2408 return; 2409 } 2410 2411 if (lst == FUNC && rst == FUNC) { 2412 /* TODO: C99 behaves like C90 here, see C99 6.5.8p2. */ 2413 if ((!allow_trad && !allow_c99) && op != EQ && op != NE) 2414 /* ANSI C forbids ordered comparisons of ... */ 2415 warning(125); 2416 } 2417 } 2418 2419 static bool 2420 typeok_compare(op_t op, 2421 const tnode_t *ln, const type_t *ltp, tspec_t lt, 2422 const tnode_t *rn, const type_t *rtp, tspec_t rt) 2423 { 2424 if (lt == PTR && rt == PTR) { 2425 check_pointer_comparison(op, ln, rn); 2426 return true; 2427 } 2428 2429 if (lt != PTR && rt != PTR) 2430 return true; 2431 2432 if (!is_integer(lt) && !is_integer(rt)) { 2433 warn_incompatible_types(op, ltp, lt, rtp, rt); 2434 return false; 2435 } 2436 2437 const char *lx = lt == PTR ? "pointer" : "integer"; 2438 const char *rx = rt == PTR ? "pointer" : "integer"; 2439 /* illegal combination of %s '%s' and %s '%s', op '%s' */ 2440 warning(123, lx, type_name(ltp), rx, type_name(rtp), op_name(op)); 2441 return true; 2442 } 2443 2444 static bool 2445 typeok_quest(tspec_t lt, const tnode_t *rn) 2446 { 2447 if (!is_scalar(lt)) { 2448 /* first operand of '?' must have scalar type */ 2449 error(170); 2450 return false; 2451 } 2452 lint_assert(before_conversion(rn)->tn_op == COLON); 2453 return true; 2454 } 2455 2456 static void 2457 typeok_colon_pointer(const type_t *ltp, const type_t *rtp) 2458 { 2459 type_t *lstp = ltp->t_subt; 2460 type_t *rstp = rtp->t_subt; 2461 tspec_t lst = lstp->t_tspec; 2462 tspec_t rst = rstp->t_tspec; 2463 2464 if ((lst == VOID && rst == FUNC) || (lst == FUNC && rst == VOID)) { 2465 /* (void *)0 is handled in typeok_colon */ 2466 /* TODO: C99 behaves like C90 here. */ 2467 if (!allow_trad && !allow_c99) 2468 /* ANSI C forbids conversion of %s to %s, op %s */ 2469 warning(305, "function pointer", "'void *'", 2470 op_name(COLON)); 2471 return; 2472 } 2473 2474 if (pointer_types_are_compatible(lstp, rstp, true)) 2475 return; 2476 if (!types_compatible(lstp, rstp, true, false, NULL)) 2477 warn_incompatible_pointers(COLON, ltp, rtp); 2478 } 2479 2480 static bool 2481 typeok_colon(const tnode_t *ln, const type_t *ltp, tspec_t lt, 2482 const tnode_t *rn, const type_t *rtp, tspec_t rt) 2483 { 2484 2485 if (is_arithmetic(lt) && is_arithmetic(rt)) 2486 return true; 2487 if (lt == BOOL && rt == BOOL) 2488 return true; 2489 2490 if (lt == STRUCT && rt == STRUCT && ltp->t_sou == rtp->t_sou) 2491 return true; 2492 if (lt == UNION && rt == UNION && ltp->t_sou == rtp->t_sou) 2493 return true; 2494 2495 if (lt == PTR && is_null_pointer(rn)) 2496 return true; 2497 if (rt == PTR && is_null_pointer(ln)) 2498 return true; 2499 2500 if ((lt == PTR && is_integer(rt)) || (is_integer(lt) && rt == PTR)) { 2501 const char *lx = lt == PTR ? "pointer" : "integer"; 2502 const char *rx = rt == PTR ? "pointer" : "integer"; 2503 /* illegal combination of %s '%s' and %s '%s', op '%s' */ 2504 warning(123, lx, type_name(ltp), 2505 rx, type_name(rtp), op_name(COLON)); 2506 return true; 2507 } 2508 2509 if (lt == VOID || rt == VOID) { 2510 if (lt != VOID || rt != VOID) 2511 /* incompatible types '%s' and '%s' in conditional */ 2512 warning(126, type_name(ltp), type_name(rtp)); 2513 return true; 2514 } 2515 2516 if (lt == PTR && rt == PTR) { 2517 typeok_colon_pointer(ltp, rtp); 2518 return true; 2519 } 2520 2521 /* incompatible types '%s' and '%s' in conditional */ 2522 error(126, type_name(ltp), type_name(rtp)); 2523 return false; 2524 } 2525 2526 /* 2527 * Returns true if the given structure or union has a constant member 2528 * (maybe recursively). 2529 */ 2530 static bool 2531 has_constant_member(const type_t *tp) 2532 { 2533 lint_assert(is_struct_or_union(tp->t_tspec)); 2534 2535 for (sym_t *m = tp->t_sou->sou_first_member; 2536 m != NULL; m = m->s_next) { 2537 const type_t *mtp = m->s_type; 2538 if (mtp->t_const) 2539 return true; 2540 if (is_struct_or_union(mtp->t_tspec) && 2541 has_constant_member(mtp)) 2542 return true; 2543 } 2544 return false; 2545 } 2546 2547 static bool 2548 typeok_assign(op_t op, const tnode_t *ln, const type_t *ltp, tspec_t lt) 2549 { 2550 if (op == RETURN || op == INIT || op == FARG) 2551 return true; 2552 2553 if (!ln->tn_lvalue) { 2554 if (ln->tn_op == CVT && ln->tn_cast && 2555 ln->tn_left->tn_op == LOAD) { 2556 /* a cast does not yield an lvalue */ 2557 error(163); 2558 } 2559 /* %soperand of '%s' must be lvalue */ 2560 error(114, "left ", op_name(op)); 2561 return false; 2562 } else if (ltp->t_const 2563 || (is_struct_or_union(lt) && has_constant_member(ltp))) { 2564 if (allow_c90) 2565 /* %soperand of '%s' must be modifiable lvalue */ 2566 warning(115, "left ", op_name(op)); 2567 } 2568 return true; 2569 } 2570 2571 /* Check the types using the information from modtab[]. */ 2572 static bool 2573 typeok_scalar(op_t op, const mod_t *mp, 2574 const type_t *ltp, tspec_t lt, 2575 const type_t *rtp, tspec_t rt) 2576 { 2577 if (mp->m_takes_bool && lt == BOOL && rt == BOOL) 2578 return true; 2579 if (mp->m_requires_integer) { 2580 if (!is_integer(lt) || (mp->m_binary && !is_integer(rt))) { 2581 warn_incompatible_types(op, ltp, lt, rtp, rt); 2582 return false; 2583 } 2584 } else if (mp->m_requires_integer_or_complex) { 2585 if ((!is_integer(lt) && !is_complex(lt)) || 2586 (mp->m_binary && (!is_integer(rt) && !is_complex(rt)))) { 2587 warn_incompatible_types(op, ltp, lt, rtp, rt); 2588 return false; 2589 } 2590 } else if (mp->m_requires_scalar) { 2591 if (!is_scalar(lt) || (mp->m_binary && !is_scalar(rt))) { 2592 warn_incompatible_types(op, ltp, lt, rtp, rt); 2593 return false; 2594 } 2595 } else if (mp->m_requires_arith) { 2596 if (!is_arithmetic(lt) || 2597 (mp->m_binary && !is_arithmetic(rt))) { 2598 warn_incompatible_types(op, ltp, lt, rtp, rt); 2599 return false; 2600 } 2601 } 2602 return true; 2603 } 2604 2605 static void 2606 check_assign_void_pointer(op_t op, int arg, 2607 tspec_t lt, tspec_t lst, 2608 tspec_t rt, tspec_t rst) 2609 { 2610 2611 if (!(lt == PTR && rt == PTR && (lst == VOID || rst == VOID))) 2612 return; 2613 /* two pointers, at least one pointer to void */ 2614 2615 /* TODO: C99 behaves like C90 here. */ 2616 if (!((!allow_trad && !allow_c99) && (lst == FUNC || rst == FUNC))) 2617 return; 2618 /* comb. of ptr to func and ptr to void */ 2619 2620 const char *lts, *rts; 2621 *(lst == FUNC ? <s : &rts) = "function pointer"; 2622 *(lst == VOID ? <s : &rts) = "'void *'"; 2623 2624 switch (op) { 2625 case INIT: 2626 case RETURN: 2627 /* ANSI C forbids conversion of %s to %s */ 2628 warning(303, rts, lts); 2629 break; 2630 case FARG: 2631 /* ANSI C forbids conversion of %s to %s, arg #%d */ 2632 warning(304, rts, lts, arg); 2633 break; 2634 default: 2635 /* ANSI C forbids conversion of %s to %s, op %s */ 2636 warning(305, rts, lts, op_name(op)); 2637 break; 2638 } 2639 } 2640 2641 static bool 2642 is_direct_function_call(const tnode_t *tn, const char **out_name) 2643 { 2644 2645 if (!(tn->tn_op == CALL && 2646 tn->tn_left->tn_op == ADDR && 2647 tn->tn_left->tn_left->tn_op == NAME)) 2648 return false; 2649 2650 *out_name = tn->tn_left->tn_left->tn_sym->s_name; 2651 return true; 2652 } 2653 2654 static bool 2655 is_unconst_function(const char *name) 2656 { 2657 2658 return strcmp(name, "memchr") == 0 || 2659 strcmp(name, "strchr") == 0 || 2660 strcmp(name, "strpbrk") == 0 || 2661 strcmp(name, "strrchr") == 0 || 2662 strcmp(name, "strstr") == 0; 2663 } 2664 2665 static bool 2666 is_const_char_pointer(const tnode_t *tn) 2667 { 2668 /* 2669 * For traditional reasons, C99 6.4.5p5 defines that string literals 2670 * have type 'char[]'. They are often implicitly converted to 2671 * 'char *', for example when they are passed as function arguments. 2672 * 2673 * C99 6.4.5p6 further defines that modifying a string that is 2674 * constructed from a string literal invokes undefined behavior. 2675 * 2676 * Out of these reasons, string literals are treated as 'effectively 2677 * const' here. 2678 */ 2679 if (tn->tn_op == CVT && 2680 tn->tn_left->tn_op == ADDR && 2681 tn->tn_left->tn_left->tn_op == STRING) 2682 return true; 2683 2684 const type_t *tp = before_conversion(tn)->tn_type; 2685 return tp->t_tspec == PTR && 2686 tp->t_subt->t_tspec == CHAR && 2687 tp->t_subt->t_const; 2688 } 2689 2690 static bool 2691 is_first_arg_const_char_pointer(const tnode_t *tn) 2692 { 2693 const tnode_t *an = tn->tn_right; 2694 if (an == NULL) 2695 return false; 2696 2697 while (an->tn_right != NULL) 2698 an = an->tn_right; 2699 return is_const_char_pointer(an->tn_left); 2700 } 2701 2702 static bool 2703 is_const_pointer(const tnode_t *tn) 2704 { 2705 const type_t *tp = before_conversion(tn)->tn_type; 2706 return tp->t_tspec == PTR && tp->t_subt->t_const; 2707 } 2708 2709 static bool 2710 is_second_arg_const_pointer(const tnode_t *tn) 2711 { 2712 const tnode_t *an = tn->tn_right; 2713 if (an == NULL || an->tn_right == NULL) 2714 return false; 2715 2716 while (an->tn_right->tn_right != NULL) 2717 an = an->tn_right; 2718 return is_const_pointer(an->tn_left); 2719 } 2720 2721 static void 2722 check_unconst_function(const type_t *lstp, const tnode_t *rn) 2723 { 2724 const char *function_name; 2725 2726 if (lstp->t_tspec == CHAR && !lstp->t_const && 2727 is_direct_function_call(rn, &function_name) && 2728 is_unconst_function(function_name) && 2729 is_first_arg_const_char_pointer(rn)) { 2730 /* call to '%s' effectively discards 'const' from argument */ 2731 warning(346, function_name); 2732 } 2733 2734 if (!lstp->t_const && 2735 is_direct_function_call(rn, &function_name) && 2736 strcmp(function_name, "bsearch") == 0 && 2737 is_second_arg_const_pointer(rn)) { 2738 /* call to '%s' effectively discards 'const' from argument */ 2739 warning(346, function_name); 2740 } 2741 } 2742 2743 static bool 2744 check_assign_void_pointer_compat(op_t op, int arg, 2745 const type_t *const ltp, tspec_t const lt, 2746 const type_t *const lstp, tspec_t const lst, 2747 const tnode_t *const rn, 2748 const type_t *const rtp, tspec_t const rt, 2749 const type_t *const rstp, tspec_t const rst) 2750 { 2751 if (!(lt == PTR && rt == PTR && (lst == VOID || rst == VOID || 2752 types_compatible(lstp, rstp, 2753 true, false, NULL)))) 2754 return false; 2755 2756 /* compatible pointer types (qualifiers ignored) */ 2757 if (allow_c90 && 2758 ((!lstp->t_const && rstp->t_const) || 2759 (!lstp->t_volatile && rstp->t_volatile))) { 2760 /* left side has not all qualifiers of right */ 2761 switch (op) { 2762 case INIT: 2763 case RETURN: 2764 /* incompatible pointer types to '%s' and '%s' */ 2765 warning(182, type_name(lstp), type_name(rstp)); 2766 break; 2767 case FARG: 2768 /* converting '%s' to incompatible '%s' ... */ 2769 warning(153, 2770 type_name(rtp), type_name(ltp), arg); 2771 break; 2772 default: 2773 /* operands of '%s' have incompatible pointer ... */ 2774 warning(128, op_name(op), 2775 type_name(lstp), type_name(rstp)); 2776 break; 2777 } 2778 } 2779 2780 if (allow_c90) 2781 check_unconst_function(lstp, rn); 2782 2783 return true; 2784 } 2785 2786 static bool 2787 check_assign_pointer_integer(op_t op, int arg, 2788 const type_t *const ltp, tspec_t const lt, 2789 const type_t *const rtp, tspec_t const rt) 2790 { 2791 2792 if (!((lt == PTR && is_integer(rt)) || (is_integer(lt) && rt == PTR))) 2793 return false; 2794 2795 const char *lx = lt == PTR ? "pointer" : "integer"; 2796 const char *rx = rt == PTR ? "pointer" : "integer"; 2797 2798 switch (op) { 2799 case INIT: 2800 case RETURN: 2801 /* illegal combination of %s '%s' and %s '%s' */ 2802 warning(183, lx, type_name(ltp), rx, type_name(rtp)); 2803 break; 2804 case FARG: 2805 /* illegal combination of %s '%s' and %s '%s', arg #%d */ 2806 warning(154, 2807 lx, type_name(ltp), rx, type_name(rtp), arg); 2808 break; 2809 default: 2810 /* illegal combination of %s '%s' and %s '%s', op '%s' */ 2811 warning(123, 2812 lx, type_name(ltp), rx, type_name(rtp), op_name(op)); 2813 break; 2814 } 2815 return true; 2816 } 2817 2818 static bool 2819 check_assign_pointer(op_t op, int arg, 2820 const type_t *ltp, tspec_t lt, 2821 const type_t *rtp, tspec_t rt) 2822 { 2823 if (!(lt == PTR && rt == PTR)) 2824 return false; 2825 2826 if (op == FARG) 2827 /* converting '%s' to incompatible '%s' for ... */ 2828 warning(153, type_name(rtp), type_name(ltp), arg); 2829 else 2830 warn_incompatible_pointers(op, ltp, rtp); 2831 return true; 2832 } 2833 2834 static void 2835 warn_assign(op_t op, int arg, 2836 const type_t *ltp, tspec_t lt, 2837 const type_t *rtp, tspec_t rt) 2838 { 2839 switch (op) { 2840 case INIT: 2841 /* cannot initialize '%s' from '%s' */ 2842 error(185, type_name(ltp), type_name(rtp)); 2843 break; 2844 case RETURN: 2845 /* function has return type '%s' but returns '%s' */ 2846 error(211, type_name(ltp), type_name(rtp)); 2847 break; 2848 case FARG: 2849 /* passing '%s' to incompatible '%s', arg #%d */ 2850 warning(155, type_name(rtp), type_name(ltp), arg); 2851 break; 2852 default: 2853 warn_incompatible_types(op, ltp, lt, rtp, rt); 2854 break; 2855 } 2856 } 2857 2858 /* 2859 * Checks type compatibility for ASSIGN, INIT, FARG and RETURN 2860 * and prints warnings/errors if necessary. 2861 * Returns whether the types are (almost) compatible. 2862 */ 2863 static bool 2864 check_assign_types_compatible(op_t op, int arg, 2865 const tnode_t *ln, const tnode_t *rn) 2866 { 2867 tspec_t lt, rt, lst = NO_TSPEC, rst = NO_TSPEC; 2868 type_t *ltp, *rtp, *lstp = NULL, *rstp = NULL; 2869 2870 if ((lt = (ltp = ln->tn_type)->t_tspec) == PTR) 2871 lst = (lstp = ltp->t_subt)->t_tspec; 2872 if ((rt = (rtp = rn->tn_type)->t_tspec) == PTR) 2873 rst = (rstp = rtp->t_subt)->t_tspec; 2874 2875 if (lt == BOOL && is_scalar(rt)) /* C99 6.3.1.2 */ 2876 return true; 2877 2878 if (is_arithmetic(lt) && (is_arithmetic(rt) || rt == BOOL)) 2879 return true; 2880 2881 if (is_struct_or_union(lt) && is_struct_or_union(rt)) 2882 /* both are struct or union */ 2883 return ltp->t_sou == rtp->t_sou; 2884 2885 /* a null pointer may be assigned to any pointer */ 2886 if (lt == PTR && is_null_pointer(rn)) { 2887 if (is_integer(rn->tn_type->t_tspec)) 2888 /* implicit conversion from integer 0 to pointer ... */ 2889 query_message(15, type_name(ltp)); 2890 return true; 2891 } 2892 2893 check_assign_void_pointer(op, arg, lt, lst, rt, rst); 2894 2895 if (check_assign_void_pointer_compat(op, arg, 2896 ltp, lt, lstp, lst, rn, rtp, rt, rstp, rst)) 2897 return true; 2898 2899 if (check_assign_pointer_integer(op, arg, ltp, lt, rtp, rt)) 2900 return true; 2901 2902 if (check_assign_pointer(op, arg, ltp, lt, rtp, rt)) 2903 return true; 2904 2905 warn_assign(op, arg, ltp, lt, rtp, rt); 2906 return false; 2907 } 2908 2909 static bool 2910 has_side_effect(const tnode_t *tn) /* NOLINT(misc-no-recursion) */ 2911 { 2912 op_t op = tn->tn_op; 2913 2914 if (modtab[op].m_has_side_effect) 2915 return true; 2916 2917 if (op == CVT && tn->tn_type->t_tspec == VOID) 2918 return has_side_effect(tn->tn_left); 2919 2920 /* XXX: Why not has_side_effect(tn->tn_left) as well? */ 2921 if (op == LOGAND || op == LOGOR) 2922 return has_side_effect(tn->tn_right); 2923 2924 /* XXX: Why not has_side_effect(tn->tn_left) as well? */ 2925 if (op == QUEST) 2926 return has_side_effect(tn->tn_right); 2927 2928 if (op == COLON || op == COMMA) { 2929 return has_side_effect(tn->tn_left) || 2930 has_side_effect(tn->tn_right); 2931 } 2932 2933 return false; 2934 } 2935 2936 static bool 2937 is_void_cast(const tnode_t *tn) 2938 { 2939 2940 return tn->tn_op == CVT && tn->tn_cast && 2941 tn->tn_type->t_tspec == VOID; 2942 } 2943 2944 static bool 2945 is_local_symbol(const tnode_t *tn) 2946 { 2947 2948 return tn->tn_op == LOAD && 2949 tn->tn_left->tn_op == NAME && 2950 tn->tn_left->tn_sym->s_scl == AUTO; 2951 } 2952 2953 static bool 2954 is_int_constant_zero(const tnode_t *tn) 2955 { 2956 2957 return tn->tn_op == CON && 2958 tn->tn_type->t_tspec == INT && 2959 tn->tn_val.u.integer == 0; 2960 } 2961 2962 static void 2963 check_null_effect(const tnode_t *tn) 2964 { 2965 2966 if (hflag && 2967 !has_side_effect(tn) && 2968 !(is_void_cast(tn) && is_local_symbol(tn->tn_left)) && 2969 !(is_void_cast(tn) && is_int_constant_zero(tn->tn_left))) { 2970 /* expression has null effect */ 2971 warning(129); 2972 } 2973 } 2974 2975 /* 2976 * Check the types for specific operators and type combinations. 2977 * 2978 * At this point, the operands already conform to the type requirements of 2979 * the operator, such as being integer, floating or scalar. 2980 */ 2981 static bool 2982 typeok_op(op_t op, int arg, 2983 const tnode_t *ln, const type_t *ltp, tspec_t lt, 2984 const tnode_t *rn, const type_t *rtp, tspec_t rt) 2985 { 2986 switch (op) { 2987 case ARROW: 2988 return typeok_arrow(lt); 2989 case POINT: 2990 return typeok_point(ln, ltp, lt); 2991 case INCBEF: 2992 case DECBEF: 2993 case INCAFT: 2994 case DECAFT: 2995 return typeok_incdec(op, ln, ltp); 2996 case INDIR: 2997 return typeok_indir(ltp, lt); 2998 case ADDR: 2999 return typeok_address(op, ln, ltp, lt); 3000 case PLUS: 3001 return typeok_plus(op, ltp, lt, rtp, rt); 3002 case MINUS: 3003 return typeok_minus(op, ltp, lt, rtp, rt); 3004 case SHL: 3005 typeok_shl(op, lt, rt); 3006 goto shift; 3007 case SHR: 3008 typeok_shr(op, ln, lt, rn, rt); 3009 shift: 3010 typeok_shift(ltp, lt, rn, rt); 3011 break; 3012 case LT: 3013 case LE: 3014 case GT: 3015 case GE: 3016 compare: 3017 return typeok_compare(op, ln, ltp, lt, rn, rtp, rt); 3018 case EQ: 3019 case NE: 3020 if (is_typeok_eq(ln, lt, rn, rt)) 3021 break; 3022 goto compare; 3023 case QUEST: 3024 return typeok_quest(lt, rn); 3025 case COLON: 3026 return typeok_colon(ln, ltp, lt, rn, rtp, rt); 3027 case ASSIGN: 3028 case INIT: 3029 case FARG: 3030 case RETURN: 3031 if (!check_assign_types_compatible(op, arg, ln, rn)) 3032 return false; 3033 goto assign; 3034 case MULASS: 3035 case DIVASS: 3036 case MODASS: 3037 goto assign; 3038 case ADDASS: 3039 case SUBASS: 3040 if ((lt == PTR && !is_integer(rt)) || rt == PTR) { 3041 warn_incompatible_types(op, ltp, lt, rtp, rt); 3042 return false; 3043 } 3044 goto assign; 3045 case SHLASS: 3046 goto assign; 3047 case SHRASS: 3048 if (pflag && !is_uinteger(lt) && 3049 !(!allow_c90 && is_uinteger(rt))) { 3050 /* bitwise '%s' on signed value possibly nonportable */ 3051 warning(117, op_name(op)); 3052 } 3053 goto assign; 3054 case ANDASS: 3055 case XORASS: 3056 case ORASS: 3057 assign: 3058 return typeok_assign(op, ln, ltp, lt); 3059 case COMMA: 3060 if (!modtab[ln->tn_op].m_has_side_effect) 3061 check_null_effect(ln); 3062 break; 3063 default: 3064 break; 3065 } 3066 return true; 3067 } 3068 3069 /* Prints a warning if a strange operator is used on an enum type. */ 3070 static void 3071 check_bad_enum_operation(op_t op, const tnode_t *ln, const tnode_t *rn) 3072 { 3073 3074 if (!eflag) 3075 return; 3076 3077 /* Allow enum in array indices. */ 3078 if (op == PLUS && 3079 ((ln->tn_type->t_is_enum && rn->tn_type->t_tspec == PTR) || 3080 (rn->tn_type->t_is_enum && ln->tn_type->t_tspec == PTR))) { 3081 return; 3082 } 3083 3084 /* dubious operation '%s' on enum */ 3085 warning(241, op_name(op)); 3086 } 3087 3088 /* Prints a warning if an operator is applied to two different enum types. */ 3089 static void 3090 check_enum_type_mismatch(op_t op, int arg, const tnode_t *ln, const tnode_t *rn) 3091 { 3092 const mod_t *mp = &modtab[op]; 3093 3094 if (ln->tn_type->t_enum != rn->tn_type->t_enum) { 3095 switch (op) { 3096 case INIT: 3097 /* enum type mismatch between '%s' and '%s' in ... */ 3098 warning(210, 3099 type_name(ln->tn_type), type_name(rn->tn_type)); 3100 break; 3101 case FARG: 3102 /* function expects '%s', passing '%s' for arg #%d */ 3103 warning(156, 3104 type_name(ln->tn_type), type_name(rn->tn_type), 3105 arg); 3106 break; 3107 case RETURN: 3108 /* function has return type '%s' but returns '%s' */ 3109 warning(211, 3110 type_name(ln->tn_type), type_name(rn->tn_type)); 3111 break; 3112 default: 3113 /* enum type mismatch: '%s' '%s' '%s' */ 3114 warning(130, type_name(ln->tn_type), op_name(op), 3115 type_name(rn->tn_type)); 3116 break; 3117 } 3118 } else if (Pflag && eflag && mp->m_comparison && op != EQ && op != NE) 3119 /* operator '%s' assumes that '%s' is ordered */ 3120 warning(243, op_name(op), type_name(ln->tn_type)); 3121 } 3122 3123 /* Prints a warning if the operands mix between enum and integer. */ 3124 static void 3125 check_enum_int_mismatch(op_t op, int arg, const tnode_t *ln, const tnode_t *rn) 3126 { 3127 3128 if (!eflag) 3129 return; 3130 3131 switch (op) { 3132 case INIT: 3133 /* 3134 * Initialization with 0 is allowed. Otherwise, all implicit 3135 * initializations would need to be warned upon as well. 3136 */ 3137 if (!rn->tn_type->t_is_enum && rn->tn_op == CON && 3138 is_integer(rn->tn_type->t_tspec) && 3139 rn->tn_val.u.integer == 0) { 3140 return; 3141 } 3142 /* initialization of '%s' with '%s' */ 3143 warning(277, type_name(ln->tn_type), type_name(rn->tn_type)); 3144 break; 3145 case FARG: 3146 /* combination of '%s' and '%s', arg #%d */ 3147 warning(278, 3148 type_name(ln->tn_type), type_name(rn->tn_type), arg); 3149 break; 3150 case RETURN: 3151 /* combination of '%s' and '%s' in return */ 3152 warning(279, type_name(ln->tn_type), type_name(rn->tn_type)); 3153 break; 3154 default: 3155 /* combination of '%s' and '%s', op '%s' */ 3156 warning(242, type_name(ln->tn_type), type_name(rn->tn_type), 3157 op_name(op)); 3158 break; 3159 } 3160 } 3161 3162 static void 3163 typeok_enum(op_t op, const mod_t *mp, int arg, 3164 const tnode_t *ln, const type_t *ltp, 3165 const tnode_t *rn, const type_t *rtp) 3166 { 3167 if (mp->m_bad_on_enum && 3168 (ltp->t_is_enum || (mp->m_binary && rtp->t_is_enum))) { 3169 check_bad_enum_operation(op, ln, rn); 3170 } else if (mp->m_valid_on_enum && 3171 (ltp->t_is_enum && rtp != NULL && rtp->t_is_enum)) { 3172 check_enum_type_mismatch(op, arg, ln, rn); 3173 } else if (mp->m_valid_on_enum && 3174 (ltp->t_is_enum || (rtp != NULL && rtp->t_is_enum))) { 3175 check_enum_int_mismatch(op, arg, ln, rn); 3176 } 3177 } 3178 3179 /* Perform most type checks. Return whether the types are ok. */ 3180 bool 3181 typeok(op_t op, int arg, const tnode_t *ln, const tnode_t *rn) 3182 { 3183 3184 const mod_t *mp = &modtab[op]; 3185 3186 type_t *ltp = ln->tn_type; 3187 tspec_t lt = ltp->t_tspec; 3188 3189 type_t *rtp = mp->m_binary ? rn->tn_type : NULL; 3190 tspec_t rt = mp->m_binary ? rtp->t_tspec : NO_TSPEC; 3191 3192 if (Tflag && !typeok_scalar_strict_bool(op, mp, arg, ln, rn)) 3193 return false; 3194 if (!typeok_scalar(op, mp, ltp, lt, rtp, rt)) 3195 return false; 3196 3197 if (!typeok_op(op, arg, ln, ltp, lt, rn, rtp, rt)) 3198 return false; 3199 3200 typeok_enum(op, mp, arg, ln, ltp, rn, rtp); 3201 return true; 3202 } 3203 3204 /* In traditional C, keep unsigned and promote FLOAT to DOUBLE. */ 3205 static tspec_t 3206 promote_trad(tspec_t t) 3207 { 3208 3209 if (t == UCHAR || t == USHORT) 3210 return UINT; 3211 if (t == CHAR || t == SCHAR || t == SHORT) 3212 return INT; 3213 if (t == FLOAT) 3214 return DOUBLE; 3215 if (t == ENUM) 3216 return INT; 3217 return t; 3218 } 3219 3220 /* 3221 * C99 6.3.1.1p2 requires for types with lower rank than int that "If an int 3222 * can represent all the values of the original type, the value is converted 3223 * to an int; otherwise it is converted to an unsigned int", and that "All 3224 * other types are unchanged by the integer promotions". 3225 */ 3226 static tspec_t 3227 promote_c90(const tnode_t *tn, tspec_t t, bool farg) 3228 { 3229 if (tn->tn_type->t_bitfield) { 3230 unsigned int width = tn->tn_type->t_bit_field_width; 3231 unsigned int int_width = size_in_bits(INT); 3232 // XXX: What about _Bool bit-fields, since C99? 3233 if (width < int_width) 3234 return INT; 3235 if (width == int_width) 3236 return is_uinteger(t) ? UINT : INT; 3237 return t; 3238 } 3239 3240 if (t == CHAR || t == SCHAR) 3241 return INT; 3242 if (t == UCHAR) 3243 return size_in_bits(CHAR) < size_in_bits(INT) ? INT : UINT; 3244 if (t == SHORT) 3245 return INT; 3246 if (t == USHORT) 3247 return size_in_bits(SHORT) < size_in_bits(INT) ? INT : UINT; 3248 if (t == ENUM) 3249 return INT; 3250 if (farg && t == FLOAT) 3251 return DOUBLE; 3252 return t; 3253 } 3254 3255 /* 3256 * Performs the "integer promotions" (C99 6.3.1.1p2), which convert small 3257 * integer types to either int or unsigned int. 3258 * 3259 * If allow_c90 is unset or the operand is a function argument with no type 3260 * information (no prototype or variable # of args), converts float to double. 3261 */ 3262 tnode_t * 3263 promote(op_t op, bool farg, tnode_t *tn) 3264 { 3265 3266 tspec_t ot = tn->tn_type->t_tspec; 3267 if (!is_arithmetic(ot)) 3268 return tn; 3269 3270 tspec_t nt = allow_c90 ? promote_c90(tn, ot, farg) : promote_trad(ot); 3271 if (nt == ot) 3272 return tn; 3273 3274 type_t *ntp = expr_dup_type(tn->tn_type); 3275 ntp->t_tspec = nt; 3276 /* 3277 * Keep t_is_enum even though t_tspec gets converted from 3278 * ENUM to INT, so we are later able to check compatibility 3279 * of enum types. 3280 */ 3281 return convert(op, 0, ntp, tn); 3282 } 3283 3284 static void 3285 convert_integer_from_floating(op_t op, const type_t *tp, const tnode_t *tn) 3286 { 3287 3288 if (op == CVT) 3289 /* cast from floating point '%s' to integer '%s' */ 3290 query_message(2, type_name(tn->tn_type), type_name(tp)); 3291 else 3292 /* implicit conversion from floating point '%s' to ... */ 3293 query_message(1, type_name(tn->tn_type), type_name(tp)); 3294 } 3295 3296 static bool 3297 should_warn_about_prototype_conversion(tspec_t nt, 3298 tspec_t ot, const tnode_t *ptn) 3299 { 3300 3301 if (nt == ot) 3302 return false; 3303 3304 if (nt == ENUM && ot == INT) 3305 return false; 3306 3307 if (is_floating(nt) != is_floating(ot) || 3308 portable_rank_cmp(nt, ot) != 0) { 3309 /* representation and/or width change */ 3310 if (!is_integer(ot)) 3311 return true; 3312 /* 3313 * XXX: Investigate whether this rule makes sense; see 3314 * tests/usr.bin/xlint/lint1/platform_long.c. 3315 */ 3316 return portable_rank_cmp(ot, INT) > 0; 3317 } 3318 3319 if (!hflag) 3320 return false; 3321 3322 /* 3323 * If the types differ only in sign and the argument has the same 3324 * representation in both types, print no warning. 3325 */ 3326 if (ptn->tn_op == CON && is_integer(nt) && 3327 signed_type(nt) == signed_type(ot) && 3328 !msb(ptn->tn_val.u.integer, ot)) 3329 return false; 3330 3331 return true; 3332 } 3333 3334 /* 3335 * Warn if a prototype causes a type conversion that is different from what 3336 * would happen to the same argument in the absence of a prototype. This 3337 * check is intended for code that needs to stay compatible with pre-C90 C. 3338 * 3339 * Errors/warnings about illegal type combinations are already printed 3340 * in check_assign_types_compatible(). 3341 */ 3342 static void 3343 check_prototype_conversion(int arg, tspec_t nt, tspec_t ot, type_t *tp, 3344 tnode_t *tn) 3345 { 3346 3347 if (!is_arithmetic(nt) || !is_arithmetic(ot)) 3348 return; 3349 3350 /* 3351 * If the type of the formal parameter is char/short, a warning 3352 * would be useless, because functions declared the old style 3353 * can't expect char/short arguments. 3354 */ 3355 if (nt == CHAR || nt == SCHAR || nt == UCHAR || 3356 nt == SHORT || nt == USHORT) 3357 return; 3358 3359 /* apply the default promotion */ 3360 tnode_t *ptn = promote(NOOP, true, tn); 3361 ot = ptn->tn_type->t_tspec; 3362 3363 if (should_warn_about_prototype_conversion(nt, ot, ptn)) { 3364 /* argument %d is converted from '%s' to '%s' ... */ 3365 warning(259, arg, type_name(tn->tn_type), type_name(tp)); 3366 } 3367 } 3368 3369 /* 3370 * When converting a large integer type to a small integer type, in some 3371 * cases the value of the actual expression is further restricted than the 3372 * type bounds, such as in (expr & 0xFF) or (expr % 100) or (expr >> 24). 3373 */ 3374 static bool 3375 can_represent(const type_t *tp, const tnode_t *tn) 3376 { 3377 3378 debug_step("%s: type '%s'", __func__, type_name(tp)); 3379 debug_node(tn); 3380 3381 uint64_t nmask = value_bits(width_in_bits(tp)); 3382 if (!is_uinteger(tp->t_tspec)) 3383 nmask >>= 1; 3384 3385 integer_constraints c = ic_expr(tn); 3386 if ((~c.bclr & ~nmask) == 0) 3387 return true; 3388 3389 integer_constraints tpc = ic_any(tp); 3390 if (is_uinteger(tp->t_tspec) 3391 ? tpc.umin <= c.umin && tpc.umax >= c.umax 3392 : tpc.smin <= c.smin && tpc.smax >= c.smax) 3393 return true; 3394 3395 return false; 3396 } 3397 3398 static void 3399 convert_integer_from_integer(op_t op, int arg, tspec_t nt, tspec_t ot, 3400 type_t *tp, tnode_t *tn) 3401 { 3402 3403 if (tn->tn_op == CON) 3404 return; 3405 3406 if (op == CVT) 3407 return; 3408 3409 if (Pflag && pflag && aflag > 0 && 3410 portable_rank_cmp(nt, ot) > 0 && 3411 is_uinteger(nt) != is_uinteger(ot)) { 3412 if (op == FARG) { 3413 /* conversion to '%s' may sign-extend ... */ 3414 warning(297, type_name(tp), arg); 3415 } else { 3416 /* conversion to '%s' may sign-extend ... */ 3417 warning(131, type_name(tp)); 3418 } 3419 } 3420 3421 if (Pflag && portable_rank_cmp(nt, ot) > 0 && 3422 (tn->tn_op == PLUS || tn->tn_op == MINUS || tn->tn_op == MULT || 3423 tn->tn_op == SHL)) { 3424 /* suggest cast from '%s' to '%s' on op '%s' to ... */ 3425 warning(324, type_name(gettyp(ot)), type_name(tp), 3426 op_name(tn->tn_op)); 3427 } 3428 3429 if (aflag > 0 && 3430 portable_rank_cmp(nt, ot) < 0 && 3431 (portable_rank_cmp(ot, LONG) >= 0 || aflag > 1) && 3432 // XXX: The portable_rank_cmp above aims at portable mode, 3433 // independent of the current platform, while can_represent acts 3434 // on the actual type sizes from the current platform. This mix 3435 // is inconsistent, but anything else would make the exact 3436 // conditions too complicated to grasp. 3437 !can_represent(tp, tn)) { 3438 if (op == FARG) { 3439 /* conversion from '%s' to '%s' may lose ... */ 3440 warning(298, 3441 type_name(tn->tn_type), type_name(tp), arg); 3442 } else { 3443 /* conversion from '%s' to '%s' may lose accuracy */ 3444 warning(132, 3445 type_name(tn->tn_type), type_name(tp)); 3446 } 3447 } 3448 3449 if (any_query_enabled && is_uinteger(nt) != is_uinteger(ot)) 3450 /* implicit conversion changes sign from '%s' to '%s' */ 3451 query_message(3, type_name(tn->tn_type), type_name(tp)); 3452 } 3453 3454 static void 3455 convert_integer_from_pointer(op_t op, tspec_t nt, type_t *tp, tnode_t *tn) 3456 { 3457 3458 if (tn->tn_op == CON) 3459 return; 3460 if (op != CVT) 3461 return; /* We already got an error. */ 3462 if (portable_rank_cmp(nt, PTR) >= 0) 3463 return; 3464 3465 if (pflag && size_in_bits(nt) >= size_in_bits(PTR)) { 3466 /* conversion of pointer to '%s' may lose bits */ 3467 warning(134, type_name(tp)); 3468 } else { 3469 /* conversion of pointer to '%s' loses bits */ 3470 warning(133, type_name(tp)); 3471 } 3472 } 3473 3474 static bool 3475 struct_starts_with(const type_t *struct_tp, const type_t *member_tp) 3476 { 3477 3478 return struct_tp->t_sou->sou_first_member != NULL && 3479 types_compatible(struct_tp->t_sou->sou_first_member->s_type, 3480 member_tp, true, false, NULL); 3481 } 3482 3483 static bool 3484 is_byte_array(const type_t *tp) 3485 { 3486 3487 return tp->t_tspec == ARRAY && 3488 (tp->t_subt->t_tspec == CHAR || tp->t_subt->t_tspec == UCHAR); 3489 } 3490 3491 static bool 3492 union_contains(const type_t *utp, const type_t *mtp) 3493 { 3494 for (const sym_t *mem = utp->t_sou->sou_first_member; 3495 mem != NULL; mem = mem->s_next) { 3496 if (types_compatible(mem->s_type, mtp, true, false, NULL)) 3497 return true; 3498 } 3499 return false; 3500 } 3501 3502 static bool 3503 should_warn_about_pointer_cast(const type_t *nstp, tspec_t nst, 3504 const type_t *ostp, tspec_t ost) 3505 { 3506 3507 while (nst == ARRAY) 3508 nstp = nstp->t_subt, nst = nstp->t_tspec; 3509 while (ost == ARRAY) 3510 ostp = ostp->t_subt, ost = ostp->t_tspec; 3511 3512 if (nst == STRUCT && ost == STRUCT && 3513 (struct_starts_with(nstp, ostp) || 3514 struct_starts_with(ostp, nstp))) 3515 return false; 3516 3517 if (is_incomplete(nstp) || is_incomplete(ostp)) 3518 return false; 3519 3520 if (nst == CHAR || nst == UCHAR) 3521 return false; /* for the sake of traditional C code */ 3522 if (ost == CHAR || ost == UCHAR) 3523 return false; /* for the sake of traditional C code */ 3524 3525 /* Allow cast between pointers to sockaddr variants. */ 3526 if (nst == STRUCT && ost == STRUCT) { 3527 const sym_t *nmem = nstp->t_sou->sou_first_member; 3528 const sym_t *omem = ostp->t_sou->sou_first_member; 3529 while (nmem != NULL && omem != NULL && 3530 types_compatible(nmem->s_type, omem->s_type, 3531 true, false, NULL)) 3532 nmem = nmem->s_next, omem = omem->s_next; 3533 if (nmem != NULL && is_byte_array(nmem->s_type)) 3534 return false; 3535 if (omem != NULL && is_byte_array(omem->s_type)) 3536 return false; 3537 if (nmem == NULL && omem == NULL) 3538 return false; 3539 } 3540 3541 if (nst == UNION || ost == UNION) { 3542 const type_t *union_tp = nst == UNION ? nstp : ostp; 3543 const type_t *other_tp = nst == UNION ? ostp : nstp; 3544 if (union_contains(union_tp, other_tp)) 3545 return false; 3546 } 3547 3548 if (is_struct_or_union(nst) && is_struct_or_union(ost)) 3549 return nstp->t_sou != ostp->t_sou; 3550 3551 enum rank_kind rk1 = type_properties(nst)->tt_rank_kind; 3552 enum rank_kind rk2 = type_properties(ost)->tt_rank_kind; 3553 if (rk1 != rk2 || rk1 == RK_NONE) 3554 return true; 3555 3556 return portable_rank_cmp(nst, ost) != 0; 3557 } 3558 3559 static void 3560 convert_pointer_from_pointer(type_t *ntp, tnode_t *tn) 3561 { 3562 const type_t *nstp = ntp->t_subt; 3563 const type_t *otp = tn->tn_type; 3564 const type_t *ostp = otp->t_subt; 3565 tspec_t nst = nstp->t_tspec; 3566 tspec_t ost = ostp->t_tspec; 3567 3568 if (nst == VOID || ost == VOID) { 3569 /* TODO: C99 behaves like C90 here. */ 3570 if ((!allow_trad && !allow_c99) && (nst == FUNC || ost == FUNC)) { 3571 const char *nts, *ots; 3572 /* null pointers are already handled in convert() */ 3573 *(nst == FUNC ? &nts : &ots) = "function pointer"; 3574 *(nst == VOID ? &nts : &ots) = "'void *'"; 3575 /* ANSI C forbids conversion of %s to %s */ 3576 warning(303, ots, nts); 3577 } 3578 return; 3579 } 3580 if (nst == FUNC && ost == FUNC) 3581 return; 3582 if (nst == FUNC || ost == FUNC) { 3583 /* converting '%s' to '%s' is questionable */ 3584 warning(229, type_name(otp), type_name(ntp)); 3585 return; 3586 } 3587 3588 if (hflag && alignment_in_bits(nstp) > alignment_in_bits(ostp) && 3589 ost != CHAR && ost != UCHAR && 3590 !is_incomplete(ostp) && 3591 !(nst == UNION && union_contains(nstp, ostp))) { 3592 /* converting '%s' to '%s' increases alignment ... */ 3593 warning(135, type_name(otp), type_name(ntp), 3594 alignment_in_bits(ostp) / CHAR_SIZE, 3595 alignment_in_bits(nstp) / CHAR_SIZE); 3596 } 3597 3598 if (cflag && should_warn_about_pointer_cast(nstp, nst, ostp, ost)) { 3599 /* pointer cast from '%s' to '%s' may be troublesome */ 3600 warning(247, type_name(otp), type_name(ntp)); 3601 } 3602 } 3603 3604 /* 3605 * Insert a conversion operator, which converts the type of the node 3606 * to another given type. 3607 * 3608 * Possible values for 'op': 3609 * CVT a cast-expression 3610 * binary integer promotion for one of the operands, or a usual 3611 * arithmetic conversion 3612 * binary plain or compound assignments to bit-fields 3613 * FARG 'arg' is the number of the argument (used for warnings) 3614 * NOOP several other implicit conversions 3615 * ... 3616 */ 3617 tnode_t * 3618 convert(op_t op, int arg, type_t *tp, tnode_t *tn) 3619 { 3620 tspec_t nt = tp->t_tspec; 3621 tspec_t ot = tn->tn_type->t_tspec; 3622 3623 if (allow_trad && allow_c90 && op == FARG) 3624 check_prototype_conversion(arg, nt, ot, tp, tn); 3625 3626 if (nt == BOOL) { 3627 /* No further checks. */ 3628 3629 } else if (is_integer(nt)) { 3630 if (ot == BOOL) { 3631 /* No further checks. */ 3632 } else if (is_integer(ot)) 3633 convert_integer_from_integer(op, arg, nt, ot, tp, tn); 3634 else if (is_floating(ot)) 3635 convert_integer_from_floating(op, tp, tn); 3636 else if (ot == PTR) 3637 convert_integer_from_pointer(op, nt, tp, tn); 3638 3639 } else if (is_floating(nt)) { 3640 /* No further checks. */ 3641 3642 } else if (nt == PTR) { 3643 if (is_null_pointer(tn)) { 3644 /* a null pointer may be assigned to any pointer. */ 3645 } else if (ot == PTR && op == CVT) 3646 convert_pointer_from_pointer(tp, tn); 3647 } 3648 3649 tnode_t *ntn = expr_alloc_tnode(); 3650 ntn->tn_op = CVT; 3651 ntn->tn_type = tp; 3652 ntn->tn_cast = op == CVT; 3653 ntn->tn_sys |= tn->tn_sys; 3654 ntn->tn_right = NULL; 3655 if (tn->tn_op != CON || nt == VOID) { 3656 ntn->tn_left = tn; 3657 } else { 3658 ntn->tn_op = CON; 3659 convert_constant(op, arg, ntn->tn_type, &ntn->tn_val, 3660 &tn->tn_val); 3661 } 3662 3663 return ntn; 3664 } 3665 3666 static void 3667 convert_constant_floating(op_t op, int arg, tspec_t ot, const type_t *tp, 3668 tspec_t nt, val_t *v, val_t *nv) 3669 { 3670 long double max = 0.0, min = 0.0; 3671 3672 switch (nt) { 3673 case CHAR: 3674 max = TARG_CHAR_MAX; min = TARG_CHAR_MIN; break; 3675 case UCHAR: 3676 max = TARG_UCHAR_MAX; min = 0; break; 3677 case SCHAR: 3678 max = TARG_SCHAR_MAX; min = TARG_SCHAR_MIN; break; 3679 case SHORT: 3680 max = TARG_SHRT_MAX; min = TARG_SHRT_MIN; break; 3681 case USHORT: 3682 max = TARG_USHRT_MAX; min = 0; break; 3683 case ENUM: 3684 case INT: 3685 max = TARG_INT_MAX; min = TARG_INT_MIN; break; 3686 case UINT: 3687 max = TARG_UINT_MAX; min = 0; break; 3688 case LONG: 3689 max = TARG_LONG_MAX; min = TARG_LONG_MIN; break; 3690 case ULONG: 3691 max = TARG_ULONG_MAX; min = 0; break; 3692 case LLONG: 3693 max = LLONG_MAX; min = LLONG_MIN; break; 3694 case ULLONG: 3695 max = ULLONG_MAX; min = 0; break; 3696 case FLOAT: 3697 case FCOMPLEX: 3698 max = FLT_MAX; min = -FLT_MAX; break; 3699 case DOUBLE: 3700 case DCOMPLEX: 3701 max = DBL_MAX; min = -DBL_MAX; break; 3702 case PTR: 3703 /* Already got an error because of float --> ptr */ 3704 case LDOUBLE: 3705 case LCOMPLEX: 3706 /* LINTED 248 */ 3707 max = LDBL_MAX; min = -max; break; 3708 default: 3709 lint_assert(/*CONSTCOND*/false); 3710 } 3711 if (v->u.floating > max || v->u.floating < min) { 3712 lint_assert(nt != LDOUBLE); 3713 if (op == FARG) { 3714 /* conversion of '%s' to '%s' is out of range, ... */ 3715 warning(295, 3716 type_name(gettyp(ot)), type_name(tp), arg); 3717 } else { 3718 /* conversion of '%s' to '%s' is out of range */ 3719 warning(119, type_name(gettyp(ot)), type_name(tp)); 3720 } 3721 v->u.floating = v->u.floating > 0 ? max : min; 3722 } 3723 3724 if (nt == FLOAT || nt == FCOMPLEX) 3725 nv->u.floating = (float)v->u.floating; 3726 else if (nt == DOUBLE || nt == DCOMPLEX) 3727 nv->u.floating = (double)v->u.floating; 3728 else if (nt == LDOUBLE || nt == LCOMPLEX) 3729 nv->u.floating = v->u.floating; 3730 else 3731 nv->u.integer = (int64_t)v->u.floating; 3732 } 3733 3734 static bool 3735 convert_constant_to_floating(tspec_t nt, val_t *nv, 3736 tspec_t ot, const val_t *v) 3737 { 3738 if (nt == FLOAT) { 3739 nv->u.floating = (ot == PTR || is_uinteger(ot)) ? 3740 (float)(uint64_t)v->u.integer : (float)v->u.integer; 3741 } else if (nt == DOUBLE) { 3742 nv->u.floating = (ot == PTR || is_uinteger(ot)) ? 3743 (double)(uint64_t)v->u.integer : (double)v->u.integer; 3744 } else if (nt == LDOUBLE) { 3745 nv->u.floating = (ot == PTR || is_uinteger(ot)) 3746 ? (long double)(uint64_t)v->u.integer 3747 : (long double)v->u.integer; 3748 } else 3749 return false; 3750 return true; 3751 } 3752 3753 /* 3754 * Print a warning if bits which were set are lost due to the conversion. 3755 * This can happen with operator ORASS only. 3756 */ 3757 static void 3758 convert_constant_check_range_bitor(size_t nsz, size_t osz, const val_t *v, 3759 uint64_t xmask, op_t op) 3760 { 3761 if (nsz < osz && (v->u.integer & xmask) != 0) { 3762 /* constant truncated by conversion, op '%s' */ 3763 warning(306, op_name(op)); 3764 } 3765 } 3766 3767 /* 3768 * Print a warning if additional bits are not all 1 3769 * and the most significant bit of the old value is 1, 3770 * or if at least one (but not all) removed bit was 0. 3771 */ 3772 static void 3773 convert_constant_check_range_bitand(size_t nsz, size_t osz, 3774 uint64_t xmask, const val_t *nv, 3775 tspec_t ot, const val_t *v, 3776 const type_t *tp, op_t op) 3777 { 3778 if (nsz > osz && 3779 (nv->u.integer & bit((unsigned int)(osz - 1))) != 0 && 3780 (nv->u.integer & xmask) != xmask) { 3781 /* extra bits set to 0 in conversion of '%s' to '%s', ... */ 3782 warning(309, type_name(gettyp(ot)), 3783 type_name(tp), op_name(op)); 3784 } else if (nsz < osz && 3785 (v->u.integer & xmask) != xmask && 3786 (v->u.integer & xmask) != 0) { 3787 /* constant truncated by conversion, op '%s' */ 3788 warning(306, op_name(op)); 3789 } 3790 } 3791 3792 static void 3793 convert_constant_check_range_signed(op_t op, int arg) 3794 { 3795 if (op == ASSIGN) { 3796 /* assignment of negative constant to unsigned type */ 3797 warning(164); 3798 } else if (op == INIT) { 3799 /* initialization of unsigned with negative constant */ 3800 warning(221); 3801 } else if (op == FARG) { 3802 /* conversion of negative constant to unsigned type, ... */ 3803 warning(296, arg); 3804 } else if (modtab[op].m_comparison) { 3805 /* handled by check_integer_comparison() */ 3806 } else { 3807 /* conversion of negative constant to unsigned type */ 3808 warning(222); 3809 } 3810 } 3811 3812 /* 3813 * Loss of significant bit(s). All truncated bits of unsigned types or all 3814 * truncated bits plus the msb of the target for signed types are considered 3815 * to be significant bits. Loss of significant bits means that at least one 3816 * of the bits was set in an unsigned type or that at least one but not all 3817 * of the bits was set in a signed type. Loss of significant bits means that 3818 * it is not possible, also not with necessary casts, to convert back to the 3819 * original type. An example for a necessary cast is: 3820 * char c; int i; c = 128; 3821 * i = c; ** yields -128 ** 3822 * i = (unsigned char)c; ** yields 128 ** 3823 */ 3824 static void 3825 warn_constant_check_range_truncated(op_t op, int arg, const type_t *tp, 3826 tspec_t ot) 3827 { 3828 if (op == ASSIGN && tp->t_bitfield) 3829 /* precision lost in bit-field assignment */ 3830 warning(166); 3831 else if (op == ASSIGN) 3832 /* constant truncated by assignment */ 3833 warning(165); 3834 else if (op == INIT && tp->t_bitfield) 3835 /* bit-field initializer does not fit */ 3836 warning(180); 3837 else if (op == INIT) 3838 /* initializer does not fit */ 3839 warning(178); 3840 else if (op == CASE) 3841 /* case label affected by conversion */ 3842 warning(196); 3843 else if (op == FARG) 3844 /* conversion of '%s' to '%s' is out of range, arg #%d */ 3845 warning(295, type_name(gettyp(ot)), type_name(tp), arg); 3846 else 3847 /* conversion of '%s' to '%s' is out of range */ 3848 warning(119, type_name(gettyp(ot)), type_name(tp)); 3849 } 3850 3851 static void 3852 warn_constant_check_range_loss(op_t op, int arg, const type_t *tp, 3853 tspec_t ot) 3854 { 3855 if (op == ASSIGN && tp->t_bitfield) 3856 /* precision lost in bit-field assignment */ 3857 warning(166); 3858 else if (op == INIT && tp->t_bitfield) 3859 /* bit-field initializer out of range */ 3860 warning(11); 3861 else if (op == CASE) 3862 /* case label affected by conversion */ 3863 warning(196); 3864 else if (op == FARG) 3865 /* conversion of '%s' to '%s' is out of range, arg #%d */ 3866 warning(295, type_name(gettyp(ot)), type_name(tp), arg); 3867 else 3868 /* conversion of '%s' to '%s' is out of range */ 3869 warning(119, type_name(gettyp(ot)), type_name(tp)); 3870 } 3871 3872 static void 3873 convert_constant_check_range(tspec_t ot, const type_t *tp, tspec_t nt, 3874 op_t op, int arg, const val_t *v, val_t *nv) 3875 { 3876 unsigned int obitsz, nbitsz; 3877 uint64_t xmask, xmsk1; 3878 3879 obitsz = size_in_bits(ot); 3880 nbitsz = tp->t_bitfield ? tp->t_bit_field_width : size_in_bits(nt); 3881 xmask = value_bits(nbitsz) ^ value_bits(obitsz); 3882 xmsk1 = value_bits(nbitsz) ^ value_bits(obitsz - 1); 3883 /* 3884 * For bitwise operations we are not interested in the arithmetic 3885 * value, but in the bits itself. 3886 */ 3887 if (op == ORASS || op == BITOR || op == BITXOR) { 3888 convert_constant_check_range_bitor( 3889 nbitsz, obitsz, v, xmask, op); 3890 } else if (op == ANDASS || op == BITAND) { 3891 convert_constant_check_range_bitand( 3892 nbitsz, obitsz, xmask, nv, ot, v, tp, op); 3893 } else if ((nt != PTR && is_uinteger(nt)) && 3894 (ot != PTR && !is_uinteger(ot)) && 3895 v->u.integer < 0) 3896 convert_constant_check_range_signed(op, arg); 3897 else if (nv->u.integer != v->u.integer && nbitsz <= obitsz && 3898 (v->u.integer & xmask) != 0 && 3899 (is_uinteger(ot) || (v->u.integer & xmsk1) != xmsk1)) 3900 warn_constant_check_range_truncated(op, arg, tp, ot); 3901 else if (nv->u.integer != v->u.integer) 3902 warn_constant_check_range_loss(op, arg, tp, ot); 3903 } 3904 3905 /* 3906 * Converts a typed constant to a constant of another type. 3907 * 3908 * op operator which requires conversion 3909 * arg if op is FARG, # of argument 3910 * tp type to which to convert the constant 3911 * nv new constant 3912 * v old constant 3913 */ 3914 void 3915 convert_constant(op_t op, int arg, const type_t *tp, val_t *nv, val_t *v) 3916 { 3917 /* 3918 * TODO: make 'v' const; the name of this function does not suggest 3919 * that it modifies 'v'. 3920 */ 3921 tspec_t ot = v->v_tspec; 3922 tspec_t nt = nv->v_tspec = tp->t_tspec; 3923 bool range_check = false; 3924 3925 if (nt == BOOL) { /* C99 6.3.1.2 */ 3926 nv->v_unsigned_since_c90 = false; 3927 nv->u.integer = is_nonzero_val(v) ? 1 : 0; 3928 return; 3929 } 3930 3931 if (ot == FLOAT || ot == DOUBLE || ot == LDOUBLE) 3932 convert_constant_floating(op, arg, ot, tp, nt, v, nv); 3933 else if (!convert_constant_to_floating(nt, nv, ot, v)) { 3934 range_check = true; /* Check for lost precision. */ 3935 nv->u.integer = v->u.integer; 3936 } 3937 3938 if (allow_trad && allow_c90 && v->v_unsigned_since_c90 && 3939 (is_floating(nt) || ( 3940 (is_integer(nt) && !is_uinteger(nt) && 3941 portable_rank_cmp(nt, ot) > 0)))) { 3942 /* ANSI C treats constant as unsigned */ 3943 warning(157); 3944 v->v_unsigned_since_c90 = false; 3945 } 3946 3947 if (is_integer(nt)) { 3948 nv->u.integer = convert_integer(nv->u.integer, nt, 3949 tp->t_bitfield ? tp->t_bit_field_width : size_in_bits(nt)); 3950 } 3951 3952 if (range_check && op != CVT) 3953 convert_constant_check_range(ot, tp, nt, op, arg, v, nv); 3954 } 3955 3956 /* 3957 * Create a constant node for sizeof. 3958 */ 3959 tnode_t * 3960 build_sizeof(const type_t *tp) 3961 { 3962 unsigned int size_in_bytes = type_size_in_bits(tp) / CHAR_SIZE; 3963 tnode_t *tn = build_integer_constant(SIZEOF_TSPEC, size_in_bytes); 3964 tn->tn_system_dependent = true; 3965 debug_step("build_sizeof '%s' = %u", type_name(tp), size_in_bytes); 3966 return tn; 3967 } 3968 3969 /* 3970 * Create a constant node for offsetof. 3971 */ 3972 /* ARGSUSED */ /* FIXME: See implementation comments. */ 3973 tnode_t * 3974 build_offsetof(const type_t *tp, const sym_t *sym) 3975 { 3976 3977 if (!is_struct_or_union(tp->t_tspec)) 3978 /* unacceptable operand of '%s' */ 3979 error(111, "offsetof"); 3980 3981 /* FIXME: Don't wrongly use the size of the whole type, use sym. */ 3982 unsigned int offset_in_bytes = type_size_in_bits(tp) / CHAR_SIZE; 3983 tnode_t *tn = build_integer_constant(SIZEOF_TSPEC, offset_in_bytes); 3984 tn->tn_system_dependent = true; 3985 return tn; 3986 } 3987 3988 unsigned int 3989 type_size_in_bits(const type_t *tp) 3990 { 3991 3992 unsigned int elem = 1; 3993 bool flex = false; 3994 lint_assert(tp != NULL); 3995 while (tp->t_tspec == ARRAY) { 3996 flex = true; /* allow c99 flex arrays [] [0] */ 3997 elem *= tp->t_dim; 3998 tp = tp->t_subt; 3999 } 4000 if (elem == 0 && !flex) { 4001 /* cannot take size/alignment of incomplete type */ 4002 error(143); 4003 elem = 1; 4004 } 4005 4006 unsigned int elsz; 4007 switch (tp->t_tspec) { 4008 case VOID: 4009 /* cannot take size/alignment of void */ 4010 error(146); 4011 elsz = 1; 4012 break; 4013 case FUNC: 4014 /* cannot take size/alignment of function type '%s' */ 4015 error(144, type_name(tp)); 4016 elsz = 1; 4017 break; 4018 case STRUCT: 4019 case UNION: 4020 if (is_incomplete(tp)) { 4021 /* cannot take size/alignment of incomplete type */ 4022 error(143); 4023 elsz = 1; 4024 } else { 4025 elsz = tp->t_sou->sou_size_in_bits; 4026 } 4027 break; 4028 case ENUM: 4029 if (is_incomplete(tp)) { 4030 /* cannot take size/alignment of incomplete type */ 4031 warning(143); 4032 } 4033 /* FALLTHROUGH */ 4034 default: 4035 if (tp->t_bitfield) { 4036 /* cannot take size/alignment of bit-field */ 4037 error(145); 4038 } 4039 elsz = size_in_bits(tp->t_tspec); 4040 lint_assert(elsz > 0); 4041 break; 4042 } 4043 4044 return elem * elsz; 4045 } 4046 4047 /* C11 6.5.3.4, GCC */ 4048 tnode_t * 4049 build_alignof(const type_t *tp) 4050 { 4051 if (tp->t_tspec == FUNC) { 4052 /* cannot take size/alignment of function type '%s' */ 4053 error(144, type_name(tp)); 4054 return NULL; 4055 } 4056 if (tp->t_tspec == VOID) { 4057 /* cannot take size/alignment of void */ 4058 error(146); 4059 return NULL; 4060 } 4061 if (is_incomplete(tp)) { 4062 /* cannot take size/alignment of incomplete type */ 4063 error(143); 4064 return NULL; 4065 } 4066 if (tp->t_bitfield) { 4067 /* cannot take size/alignment of bit-field */ 4068 error(145); 4069 return NULL; 4070 } 4071 return build_integer_constant(SIZEOF_TSPEC, 4072 (int64_t)alignment_in_bits(tp) / CHAR_SIZE); 4073 } 4074 4075 static tnode_t * 4076 cast_to_union(tnode_t *otn, type_t *ntp) 4077 { 4078 4079 if (!allow_gcc) { 4080 /* union cast is a GCC extension */ 4081 error(328); 4082 return NULL; 4083 } 4084 4085 for (const sym_t *m = ntp->t_sou->sou_first_member; 4086 m != NULL; m = m->s_next) { 4087 if (types_compatible(m->s_type, otn->tn_type, 4088 false, false, NULL)) { 4089 tnode_t *ntn = expr_alloc_tnode(); 4090 ntn->tn_op = CVT; 4091 ntn->tn_type = ntp; 4092 ntn->tn_cast = true; 4093 ntn->tn_left = otn; 4094 ntn->tn_right = NULL; 4095 return ntn; 4096 } 4097 } 4098 4099 /* type '%s' is not a member of '%s' */ 4100 error(329, type_name(otn->tn_type), type_name(ntp)); 4101 return NULL; 4102 } 4103 4104 /* 4105 * Type casts. 4106 */ 4107 tnode_t * 4108 cast(tnode_t *tn, type_t *tp) 4109 { 4110 4111 if (tn == NULL) 4112 return NULL; 4113 4114 tn = cconv(tn); 4115 4116 lint_assert(tp != NULL); 4117 tspec_t nt = tp->t_tspec; 4118 tspec_t ot = tn->tn_type->t_tspec; 4119 4120 if (nt == VOID) { 4121 /* 4122 * C90 6.3.4, C99 6.5.4p2 and C11 6.5.4p2 allow any type to 4123 * be cast to void. The only other allowed casts are from a 4124 * scalar type to a scalar type. 4125 */ 4126 } else if (nt == UNION) 4127 return cast_to_union(tn, tp); 4128 else if (nt == STRUCT || nt == ARRAY || nt == FUNC) { 4129 /* Casting to a struct is an undocumented GCC extension. */ 4130 if (!(allow_gcc && nt == STRUCT)) 4131 goto invalid_cast; 4132 } else if (is_struct_or_union(ot)) 4133 goto invalid_cast; 4134 else if (ot == VOID) { 4135 /* improper cast of void expression */ 4136 error(148); 4137 return NULL; 4138 } else if (is_integer(nt) && is_scalar(ot)) { 4139 /* ok */ 4140 } else if (is_floating(nt) && is_arithmetic(ot)) { 4141 /* ok */ 4142 } else if (nt == PTR && is_integer(ot)) { 4143 /* ok */ 4144 } else if (nt == PTR && ot == PTR) { 4145 if (!tp->t_subt->t_const && tn->tn_type->t_subt->t_const) { 4146 if (hflag) 4147 /* cast discards 'const' from type '%s' */ 4148 warning(275, type_name(tn->tn_type)); 4149 } 4150 } else 4151 goto invalid_cast; 4152 4153 if (any_query_enabled && types_compatible(tp, tn->tn_type, 4154 false, false, NULL)) { 4155 /* no-op cast from '%s' to '%s' */ 4156 query_message(6, type_name(tn->tn_type), type_name(tp)); 4157 } 4158 4159 tn = convert(CVT, 0, tp, tn); 4160 tn->tn_cast = true; 4161 4162 return tn; 4163 4164 invalid_cast: 4165 /* invalid cast from '%s' to '%s' */ 4166 error(147, type_name(tn->tn_type), type_name(tp)); 4167 return NULL; 4168 } 4169 4170 /* 4171 * Create the node for a function argument. 4172 * All necessary conversions and type checks are done in 4173 * build_function_call because build_function_argument has no 4174 * information about expected argument types. 4175 */ 4176 tnode_t * 4177 build_function_argument(tnode_t *args, tnode_t *arg) 4178 { 4179 /* 4180 * If there was a serious error in the expression for the argument, 4181 * create a dummy argument so the positions of the remaining arguments 4182 * will not change. 4183 */ 4184 if (arg == NULL) 4185 arg = build_integer_constant(INT, 0); 4186 4187 return build_op(PUSH, arg->tn_sys, arg->tn_type, arg, args); 4188 } 4189 4190 /* 4191 * Compare the type of an argument with the corresponding type of a 4192 * prototype parameter. If it is a valid combination, but both types 4193 * are not the same, insert a conversion to convert the argument into 4194 * the type of the parameter. 4195 */ 4196 static tnode_t * 4197 check_prototype_argument( 4198 int n, /* pos of arg */ 4199 type_t *tp, /* expected type (from prototype) */ 4200 tnode_t *tn) /* argument */ 4201 { 4202 tnode_t *ln = xcalloc(1, sizeof(*ln)); 4203 ln->tn_type = expr_unqualified_type(tp); 4204 ln->tn_lvalue = true; 4205 if (typeok(FARG, n, ln, tn)) { 4206 bool dowarn; 4207 if (!types_compatible(tp, tn->tn_type, 4208 true, false, (dowarn = false, &dowarn)) || dowarn) 4209 tn = convert(FARG, n, tp, tn); 4210 } 4211 free(ln); 4212 return tn; 4213 } 4214 4215 /* 4216 * Check types of all function arguments and insert conversions, 4217 * if necessary. 4218 */ 4219 static tnode_t * 4220 check_function_arguments(type_t *ftp, tnode_t *args) 4221 { 4222 /* get # of parameters in the prototype */ 4223 int npar = 0; 4224 for (sym_t *asym = ftp->t_args; asym != NULL; asym = asym->s_next) 4225 npar++; 4226 4227 /* get # of arguments in the function call */ 4228 int narg = 0; 4229 for (tnode_t *arg = args; arg != NULL; arg = arg->tn_right) 4230 narg++; 4231 4232 sym_t *asym = ftp->t_args; 4233 if (ftp->t_proto && npar != narg && !(ftp->t_vararg && npar < narg)) { 4234 /* argument mismatch: %d %s passed, %d expected */ 4235 error(150, narg, narg > 1 ? "arguments" : "argument", npar); 4236 asym = NULL; 4237 } 4238 4239 for (int n = 1; n <= narg; n++) { 4240 4241 /* 4242 * The rightmost argument is at the top of the argument 4243 * subtree. 4244 */ 4245 tnode_t *arg = args; 4246 for (int i = narg; i > n; i--, arg = arg->tn_right) 4247 continue; 4248 4249 /* some things which are always not allowed */ 4250 tspec_t at = arg->tn_left->tn_type->t_tspec; 4251 if (at == VOID) { 4252 /* void expressions may not be arguments, arg #%d */ 4253 error(151, n); 4254 return NULL; 4255 } else if (is_struct_or_union(at) && 4256 is_incomplete(arg->tn_left->tn_type)) { 4257 /* argument cannot have unknown size, arg #%d */ 4258 error(152, n); 4259 return NULL; 4260 } else if (is_integer(at) && 4261 arg->tn_left->tn_type->t_is_enum && 4262 is_incomplete(arg->tn_left->tn_type)) { 4263 /* argument cannot have unknown size, arg #%d */ 4264 warning(152, n); 4265 } 4266 4267 /* class conversions (arg in value context) */ 4268 arg->tn_left = cconv(arg->tn_left); 4269 4270 if (asym != NULL) { 4271 arg->tn_left = check_prototype_argument( 4272 n, asym->s_type, arg->tn_left); 4273 } else 4274 arg->tn_left = promote(NOOP, true, arg->tn_left); 4275 arg->tn_type = arg->tn_left->tn_type; 4276 4277 if (asym != NULL) 4278 asym = asym->s_next; 4279 } 4280 4281 return args; 4282 } 4283 4284 /* 4285 * Create the node for a function call. Also check types of 4286 * function arguments and insert conversions, if necessary. 4287 */ 4288 tnode_t * 4289 build_function_call(tnode_t *func, bool sys, tnode_t *args) 4290 { 4291 4292 if (func == NULL) 4293 return NULL; 4294 4295 op_t fcop = func->tn_op == NAME && func->tn_type->t_tspec == FUNC 4296 ? CALL : ICALL; 4297 4298 check_ctype_function_call(func, args); 4299 4300 /* Turn the function name into a pointer to the function. */ 4301 func = cconv(func); 4302 4303 if (func->tn_type->t_tspec != PTR || 4304 func->tn_type->t_subt->t_tspec != FUNC) { 4305 /* cannot call '%s', must be a function */ 4306 error(149, type_name(func->tn_type)); 4307 return NULL; 4308 } 4309 4310 args = check_function_arguments(func->tn_type->t_subt, args); 4311 4312 return build_op(fcop, sys, func->tn_type->t_subt->t_subt, func, args); 4313 } 4314 4315 /* 4316 * Return the value of an integral constant expression. 4317 * If the expression is not constant or its type is not an integer 4318 * type, an error message is printed. 4319 */ 4320 val_t * 4321 integer_constant(tnode_t *tn, bool required) 4322 { 4323 4324 if (tn != NULL) 4325 tn = cconv(tn); 4326 if (tn != NULL) 4327 tn = promote(NOOP, false, tn); 4328 4329 val_t *v = xcalloc(1, sizeof(*v)); 4330 4331 if (tn == NULL) { 4332 lint_assert(seen_error); 4333 debug_step("constant node is null; returning 1 instead"); 4334 v->v_tspec = INT; 4335 v->u.integer = 1; 4336 return v; 4337 } 4338 4339 v->v_tspec = tn->tn_type->t_tspec; 4340 4341 if (tn->tn_op == CON) { 4342 lint_assert(tn->tn_type->t_tspec == tn->tn_val.v_tspec); 4343 if (is_integer(tn->tn_val.v_tspec)) { 4344 v->v_unsigned_since_c90 = 4345 tn->tn_val.v_unsigned_since_c90; 4346 v->u.integer = tn->tn_val.u.integer; 4347 return v; 4348 } 4349 v->u.integer = (int64_t)tn->tn_val.u.floating; 4350 } else { 4351 v->u.integer = 1; 4352 } 4353 4354 if (required) 4355 /* integral constant expression expected */ 4356 error(55); 4357 else 4358 /* variable array dimension is a C99/GCC extension */ 4359 c99ism(318); 4360 4361 if (!is_integer(v->v_tspec)) 4362 v->v_tspec = INT; 4363 4364 return v; 4365 } 4366 4367 static bool 4368 is_constcond_false(const tnode_t *tn, tspec_t t) 4369 { 4370 return (t == BOOL || t == INT) && 4371 tn->tn_op == CON && tn->tn_val.u.integer == 0; 4372 } 4373 4374 /* 4375 * Perform some tests on expressions which can't be done in build_binary() 4376 * and functions called by build_binary(). These tests must be done here 4377 * because we need some information about the context in which the operations 4378 * are performed. 4379 * After all tests are performed and dofreeblk is true, expr() frees the 4380 * memory which is used for the expression. 4381 */ 4382 void 4383 expr(tnode_t *tn, bool vctx, bool cond, bool dofreeblk, bool is_do_while) 4384 { 4385 4386 if (tn == NULL) { /* in case of errors */ 4387 expr_free_all(); 4388 return; 4389 } 4390 4391 /* expr() is also called in global initializations */ 4392 if (dcs->d_kind != DLK_EXTERN && !is_do_while) 4393 check_statement_reachable(); 4394 4395 check_expr_misc(tn, vctx, cond, !cond, false, false, false); 4396 if (tn->tn_op == ASSIGN && !tn->tn_parenthesized) { 4397 if (hflag && cond) 4398 /* assignment in conditional context */ 4399 warning(159); 4400 } else if (tn->tn_op == CON) { 4401 if (hflag && cond && !suppress_constcond && 4402 !tn->tn_system_dependent && 4403 !(is_do_while && 4404 is_constcond_false(tn, tn->tn_type->t_tspec))) 4405 /* constant in conditional context */ 4406 warning(161); 4407 } 4408 if (!modtab[tn->tn_op].m_has_side_effect) { 4409 /* 4410 * for left operands of COMMA this warning is already 4411 * printed 4412 */ 4413 if (tn->tn_op != COMMA && !vctx && !cond) 4414 check_null_effect(tn); 4415 } 4416 debug_node(tn); 4417 4418 /* free the tree memory */ 4419 if (dofreeblk) 4420 expr_free_all(); 4421 } 4422 4423 /* 4424 * Checks the range of array indices, if possible. 4425 * amper is set if only the address of the element is used. This 4426 * means that the index is allowed to refer to the first element 4427 * after the array. 4428 */ 4429 static void 4430 check_array_index(tnode_t *tn, bool amper) 4431 { 4432 const tnode_t *ln = tn->tn_left; 4433 const tnode_t *rn = tn->tn_right; 4434 4435 /* We can only check constant indices. */ 4436 if (rn->tn_op != CON) 4437 return; 4438 4439 /* Return if the left node does not stem from an array. */ 4440 if (ln->tn_op != ADDR) 4441 return; 4442 if (ln->tn_left->tn_op != STRING && ln->tn_left->tn_op != NAME) 4443 return; 4444 if (ln->tn_left->tn_type->t_tspec != ARRAY) 4445 return; 4446 4447 /* 4448 * For incomplete array types, we can print a warning only if 4449 * the index is negative. 4450 */ 4451 if (is_incomplete(ln->tn_left->tn_type) && rn->tn_val.u.integer >= 0) 4452 return; 4453 4454 /* Get the size of one array element */ 4455 int elsz = length_in_bits(ln->tn_type->t_subt, NULL); 4456 if (elsz == 0) 4457 return; 4458 elsz /= CHAR_SIZE; 4459 4460 /* Change the unit of the index from bytes to element size. */ 4461 int64_t con = is_uinteger(rn->tn_type->t_tspec) 4462 ? (int64_t)((uint64_t)rn->tn_val.u.integer / elsz) 4463 : rn->tn_val.u.integer / elsz; 4464 4465 int dim = ln->tn_left->tn_type->t_dim + (amper ? 1 : 0); 4466 4467 if (!is_uinteger(rn->tn_type->t_tspec) && con < 0) { 4468 /* array subscript cannot be negative: %ld */ 4469 warning(167, (long)con); 4470 } else if (dim > 0 && (uint64_t)con >= (uint64_t)dim) { 4471 /* array subscript cannot be > %d: %ld */ 4472 warning(168, dim - 1, (long)con); 4473 } 4474 } 4475 4476 static void 4477 check_expr_addr(const tnode_t *ln, bool szof, bool fcall) 4478 { 4479 /* XXX: Taking warn_about_unreachable into account here feels wrong. */ 4480 if (ln->tn_op == NAME && (reached || !warn_about_unreachable)) { 4481 if (!szof) 4482 mark_as_set(ln->tn_sym); 4483 mark_as_used(ln->tn_sym, fcall, szof); 4484 } 4485 if (ln->tn_op == INDIR && ln->tn_left->tn_op == PLUS) 4486 /* check the range of array indices */ 4487 check_array_index(ln->tn_left, true); 4488 } 4489 4490 static void 4491 check_expr_load(const tnode_t *ln) 4492 { 4493 if (ln->tn_op == INDIR && ln->tn_left->tn_op == PLUS) 4494 /* check the range of array indices */ 4495 check_array_index(ln->tn_left, false); 4496 } 4497 4498 /* 4499 * If there is an asm statement in one of the compound statements around, 4500 * there may be other side effects, so don't warn. 4501 */ 4502 static bool 4503 is_asm_around(void) 4504 { 4505 for (decl_level *dl = dcs; dl != NULL; dl = dl->d_enclosing) 4506 if (dl->d_asm) 4507 return true; 4508 return false; 4509 } 4510 4511 static void 4512 check_expr_side_effect(const tnode_t *ln, bool szof) 4513 { 4514 4515 /* XXX: Taking warn_about_unreachable into account here feels wrong. */ 4516 if (ln->tn_op == NAME && (reached || !warn_about_unreachable)) { 4517 scl_t sc = ln->tn_sym->s_scl; 4518 if (sc != EXTERN && sc != STATIC && 4519 !ln->tn_sym->s_set && !szof && !is_asm_around()) { 4520 /* '%s' may be used before set */ 4521 warning(158, ln->tn_sym->s_name); 4522 mark_as_set(ln->tn_sym); 4523 } 4524 mark_as_used(ln->tn_sym, false, false); 4525 } 4526 } 4527 4528 static void 4529 check_expr_assign(const tnode_t *ln, bool szof) 4530 { 4531 /* XXX: Taking warn_about_unreachable into account here feels wrong. */ 4532 if (ln->tn_op == NAME && !szof && (reached || !warn_about_unreachable)) { 4533 mark_as_set(ln->tn_sym); 4534 if (ln->tn_sym->s_scl == EXTERN) 4535 outusg(ln->tn_sym); 4536 } 4537 if (ln->tn_op == INDIR && ln->tn_left->tn_op == PLUS) 4538 /* check the range of array indices */ 4539 check_array_index(ln->tn_left, false); 4540 } 4541 4542 static void 4543 check_expr_call(const tnode_t *tn, const tnode_t *ln, 4544 bool szof, bool vctx, bool cond, bool retval_discarded) 4545 { 4546 lint_assert(ln->tn_op == ADDR); 4547 lint_assert(ln->tn_left->tn_op == NAME); 4548 if (!szof && !is_compiler_builtin(ln->tn_left->tn_sym->s_name)) 4549 outcall(tn, vctx || cond, retval_discarded); 4550 } 4551 4552 static bool 4553 check_expr_op(const tnode_t *tn, op_t op, const tnode_t *ln, 4554 bool szof, bool fcall, bool vctx, bool cond, 4555 bool retval_discarded, bool eqwarn) 4556 { 4557 switch (op) { 4558 case ADDR: 4559 check_expr_addr(ln, szof, fcall); 4560 break; 4561 case LOAD: 4562 check_expr_load(ln); 4563 /* FALLTHROUGH */ 4564 case PUSH: 4565 case INCBEF: 4566 case DECBEF: 4567 case INCAFT: 4568 case DECAFT: 4569 case ADDASS: 4570 case SUBASS: 4571 case MULASS: 4572 case DIVASS: 4573 case MODASS: 4574 case ANDASS: 4575 case ORASS: 4576 case XORASS: 4577 case SHLASS: 4578 case SHRASS: 4579 case REAL: 4580 case IMAG: 4581 check_expr_side_effect(ln, szof); 4582 break; 4583 case ASSIGN: 4584 check_expr_assign(ln, szof); 4585 break; 4586 case CALL: 4587 check_expr_call(tn, ln, szof, vctx, cond, retval_discarded); 4588 break; 4589 case EQ: 4590 if (hflag && eqwarn) 4591 /* operator '==' found where '=' was expected */ 4592 warning(160); 4593 break; 4594 case CON: 4595 case NAME: 4596 case STRING: 4597 return false; 4598 default: 4599 break; 4600 } 4601 return true; 4602 } 4603 4604 /* 4605 * vctx ??? 4606 * cond whether the expression is a condition that 4607 * will be compared with 0 4608 * eqwarn whether the operator '==' might be a 4609 * misspelled '=' 4610 * fcall whether the expression is a function call 4611 * retval_discarded whether the return value of a function call 4612 * is discarded; such calls will be analyzed by 4613 * lint2 in messages 4, 8 and 9 4614 * szof whether the expression is part of a sizeof 4615 * expression, which means that its value is 4616 * discarded since only the type is relevant 4617 */ 4618 void 4619 check_expr_misc(const tnode_t *tn, bool vctx, bool cond, 4620 bool eqwarn, bool fcall, bool retval_discarded, bool szof) 4621 { 4622 4623 if (tn == NULL) 4624 return; 4625 4626 tnode_t *ln = tn->tn_left; 4627 tnode_t *rn = tn->tn_right; 4628 op_t op = tn->tn_op; 4629 const mod_t *mp = &modtab[op]; 4630 4631 if (!check_expr_op(tn, op, ln, 4632 szof, fcall, vctx, cond, retval_discarded, eqwarn)) 4633 return; 4634 4635 bool cvctx = mp->m_value_context; 4636 bool ccond = mp->m_compares_with_zero; 4637 bool eq = mp->m_warn_if_operand_eq && 4638 !ln->tn_parenthesized && 4639 rn != NULL && !rn->tn_parenthesized; 4640 4641 /* 4642 * values of operands of ':' are not used if the type of at least 4643 * one of the operands (for gcc compatibility) is void 4644 * XXX test/value context of QUEST should probably be used as 4645 * context for both operands of COLON 4646 */ 4647 if (op == COLON && tn->tn_type->t_tspec == VOID) 4648 cvctx = ccond = false; 4649 bool discard = op == CVT && tn->tn_type->t_tspec == VOID; 4650 check_expr_misc(ln, cvctx, ccond, eq, op == CALL, discard, szof); 4651 4652 switch (op) { 4653 case PUSH: 4654 if (rn != NULL) 4655 check_expr_misc(rn, false, false, eq, false, false, 4656 szof); 4657 break; 4658 case LOGAND: 4659 case LOGOR: 4660 check_expr_misc(rn, false, true, eq, false, false, szof); 4661 break; 4662 case COLON: 4663 check_expr_misc(rn, cvctx, ccond, eq, false, false, szof); 4664 break; 4665 case COMMA: 4666 check_expr_misc(rn, vctx, cond, false, false, false, szof); 4667 break; 4668 default: 4669 if (mp->m_binary) 4670 check_expr_misc(rn, true, false, eq, false, false, 4671 szof); 4672 break; 4673 } 4674 } 4675 4676 /* 4677 * Return whether the expression can be used for static initialization. 4678 * 4679 * Constant initialization expressions must be constant or an address 4680 * of a static object with an optional offset. In the first case, 4681 * the result is returned in *offsp. In the second case, the static 4682 * object is returned in *symp and the offset in *offsp. 4683 * 4684 * The expression can consist of PLUS, MINUS, ADDR, NAME, STRING and 4685 * CON. Type conversions are allowed if they do not change binary 4686 * representation (including width). 4687 * 4688 * C99 6.6 "Constant expressions" 4689 * C99 6.7.8p4 restricts initializers for static storage duration 4690 */ 4691 bool 4692 constant_addr(const tnode_t *tn, const sym_t **symp, ptrdiff_t *offsp) 4693 { 4694 const sym_t *sym; 4695 ptrdiff_t offs1, offs2; 4696 tspec_t t, ot; 4697 4698 switch (tn->tn_op) { 4699 case MINUS: 4700 if (tn->tn_right->tn_op == CVT) 4701 return constant_addr(tn->tn_right, symp, offsp); 4702 else if (tn->tn_right->tn_op != CON) 4703 return false; 4704 /* FALLTHROUGH */ 4705 case PLUS: 4706 offs1 = offs2 = 0; 4707 if (tn->tn_left->tn_op == CON) { 4708 offs1 = (ptrdiff_t)tn->tn_left->tn_val.u.integer; 4709 if (!constant_addr(tn->tn_right, &sym, &offs2)) 4710 return false; 4711 } else if (tn->tn_right->tn_op == CON) { 4712 offs2 = (ptrdiff_t)tn->tn_right->tn_val.u.integer; 4713 if (tn->tn_op == MINUS) 4714 offs2 = -offs2; 4715 if (!constant_addr(tn->tn_left, &sym, &offs1)) 4716 return false; 4717 } else { 4718 return false; 4719 } 4720 *symp = sym; 4721 *offsp = offs1 + offs2; 4722 return true; 4723 case ADDR: 4724 if (tn->tn_left->tn_op == NAME) { 4725 *symp = tn->tn_left->tn_sym; 4726 *offsp = 0; 4727 return true; 4728 } else { 4729 /* 4730 * If this were the front end of a compiler, we 4731 * would return a label instead of 0, at least if 4732 * 'tn->tn_left->tn_op == STRING'. 4733 */ 4734 *symp = NULL; 4735 *offsp = 0; 4736 return true; 4737 } 4738 case CVT: 4739 t = tn->tn_type->t_tspec; 4740 ot = tn->tn_left->tn_type->t_tspec; 4741 if ((!is_integer(t) && t != PTR) || 4742 (!is_integer(ot) && ot != PTR)) { 4743 return false; 4744 } 4745 #if 0 4746 /* 4747 * consider: 4748 * struct foo { 4749 * unsigned char a; 4750 * } f = { 4751 * (unsigned char)(unsigned long) 4752 * (&(((struct foo *)0)->a)) 4753 * }; 4754 * since psize(unsigned long) != psize(unsigned char), 4755 * this fails. 4756 */ 4757 else if (psize(t) != psize(ot)) 4758 return -1; 4759 #endif 4760 return constant_addr(tn->tn_left, symp, offsp); 4761 default: 4762 return false; 4763 } 4764 } 4765 4766 /* Append s2 to s1, then free s2. */ 4767 strg_t * 4768 cat_strings(strg_t *s1, strg_t *s2) 4769 { 4770 4771 if (s1->st_char != s2->st_char) { 4772 /* cannot concatenate wide and regular string literals */ 4773 error(292); 4774 return s1; 4775 } 4776 4777 size_t len1 = s1->st_len; 4778 size_t len2 = s2->st_len; 4779 size_t chsize = s1->st_char ? sizeof(char) : sizeof(wchar_t); 4780 size_t size1 = len1 * chsize; 4781 size_t size2 = (len2 + 1) * chsize; 4782 s1->st_mem = xrealloc(s1->st_mem, size1 + size2); 4783 memcpy((char *)s1->st_mem + size1, s2->st_mem, size2); 4784 free(s2->st_mem); 4785 4786 s1->st_len = len1 + len2; 4787 free(s2); 4788 4789 return s1; 4790 } 4791 4792 4793 typedef struct stmt_expr { 4794 memory_pool se_mem; 4795 sym_t *se_sym; 4796 struct stmt_expr *se_enclosing; 4797 } stmt_expr; 4798 4799 static stmt_expr *stmt_exprs; 4800 4801 void 4802 begin_statement_expr(void) 4803 { 4804 debug_enter(); 4805 4806 stmt_expr *se = xmalloc(sizeof(*se)); 4807 se->se_mem = expr_save_memory(); 4808 se->se_sym = NULL; 4809 se->se_enclosing = stmt_exprs; 4810 stmt_exprs = se; 4811 } 4812 4813 void 4814 do_statement_expr(tnode_t *tn) 4815 { 4816 block_level--; 4817 mem_block_level--; 4818 stmt_exprs->se_sym = tn != NULL 4819 ? mktempsym(block_dup_type(tn->tn_type)) 4820 : NULL; /* after a syntax error */ 4821 mem_block_level++; 4822 block_level++; 4823 /* '({ ... })' is a GCC extension */ 4824 gnuism(320); 4825 } 4826 4827 tnode_t * 4828 end_statement_expr(void) 4829 { 4830 tnode_t *tn; 4831 4832 stmt_expr *se = stmt_exprs; 4833 if (se->se_sym == NULL) { 4834 tn = NULL; /* after a syntax error */ 4835 goto end; 4836 } 4837 4838 tn = build_name(se->se_sym, false); 4839 (void)expr_save_memory(); /* leak */ 4840 expr_restore_memory(se->se_mem); 4841 stmt_exprs = se->se_enclosing; 4842 free(se); 4843 4844 end: 4845 debug_leave(); 4846 return tn; 4847 } 4848 4849 bool 4850 in_statement_expr(void) 4851 { 4852 return stmt_exprs != NULL; 4853 } 4854
Indexes created Tue Sep 23 07:09:52 GMT 2025