tree.c revision 1.650
1 /* $NetBSD: tree.c,v 1.650 2024/08/18 15:21:09 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 1.650 2024/08/18 15:21:09 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 { 98 const ttab_t *p1 = type_properties(t1), *p2 = type_properties(t2); 99 lint_assert(p1->tt_rank_kind == p2->tt_rank_kind); 100 lint_assert(p1->tt_rank_value > 0); 101 lint_assert(p2->tt_rank_value > 0); 102 return (int)p1->tt_rank_value - (int)p2->tt_rank_value; 103 } 104 105 static bool 106 ic_maybe_signed(const type_t *tp, const integer_constraints *ic) 107 { 108 return !is_uinteger(tp->t_tspec) && ic->bclr >> 63 == 0; 109 } 110 111 static integer_constraints 112 ic_any(const type_t *tp) 113 { 114 integer_constraints c; 115 116 uint64_t vbits = value_bits(width_in_bits(tp)); 117 if (is_uinteger(tp->t_tspec)) { 118 c.smin = INT64_MIN; 119 c.smax = INT64_MAX; 120 c.umin = 0; 121 c.umax = vbits; 122 c.bset = 0; 123 c.bclr = ~c.umax; 124 } else { 125 c.smin = (int64_t)-1 - (int64_t)(vbits >> 1); 126 c.smax = (int64_t)(vbits >> 1); 127 c.umin = 0; 128 c.umax = UINT64_MAX; 129 c.bset = 0; 130 c.bclr = 0; 131 } 132 return c; 133 } 134 135 static integer_constraints 136 ic_con(const type_t *tp, const val_t *v) 137 { 138 integer_constraints c; 139 140 lint_assert(is_integer(tp->t_tspec)); 141 int64_t si = v->u.integer; 142 uint64_t ui = (uint64_t)si; 143 c.smin = si; 144 c.smax = si; 145 c.umin = ui; 146 c.umax = ui; 147 c.bset = ui; 148 c.bclr = ~ui; 149 return c; 150 } 151 152 static integer_constraints 153 ic_cvt(const type_t *ntp, const type_t *otp, integer_constraints a) 154 { 155 unsigned nw = width_in_bits(ntp); 156 unsigned ow = width_in_bits(otp); 157 bool nu = is_uinteger(ntp->t_tspec); 158 bool ou = is_uinteger(otp->t_tspec); 159 160 if (nw >= ow && nu == ou) 161 return a; 162 if (nw > ow && ou) 163 return a; 164 return ic_any(ntp); 165 } 166 167 static integer_constraints 168 ic_bitand(integer_constraints a, integer_constraints b) 169 { 170 integer_constraints c; 171 172 c.smin = INT64_MIN; 173 c.smax = INT64_MAX; 174 c.umin = 0; 175 c.umax = ~(a.bclr | b.bclr); 176 c.bset = a.bset & b.bset; 177 c.bclr = a.bclr | b.bclr; 178 return c; 179 } 180 181 static integer_constraints 182 ic_bitor(integer_constraints a, integer_constraints b) 183 { 184 integer_constraints c; 185 186 c.smin = INT64_MIN; 187 c.smax = INT64_MAX; 188 c.umin = 0; 189 c.umax = ~(a.bclr & b.bclr); 190 c.bset = a.bset | b.bset; 191 c.bclr = a.bclr & b.bclr; 192 return c; 193 } 194 195 static integer_constraints 196 ic_mod(const type_t *tp, integer_constraints a, integer_constraints b) 197 { 198 integer_constraints c; 199 200 if (ic_maybe_signed(tp, &a) || ic_maybe_signed(tp, &b)) 201 return ic_any(tp); 202 203 c.smin = INT64_MIN; 204 c.smax = INT64_MAX; 205 c.umin = 0; 206 c.umax = b.umax - 1; 207 c.bset = 0; 208 c.bclr = ~u64_fill_right(c.umax); 209 return c; 210 } 211 212 static integer_constraints 213 ic_div(const type_t *tp, integer_constraints a, integer_constraints b) 214 { 215 integer_constraints c; 216 217 if (ic_maybe_signed(tp, &a) || ic_maybe_signed(tp, &b) || b.umin == 0) 218 return ic_any(tp); 219 220 c.smin = INT64_MIN; 221 c.smax = INT64_MAX; 222 c.umin = a.umin / b.umax; 223 c.umax = a.umax / b.umin; 224 c.bset = 0; 225 c.bclr = ~u64_fill_right(c.umax); 226 return c; 227 } 228 229 static integer_constraints 230 ic_shl(const type_t *tp, integer_constraints a, integer_constraints b) 231 { 232 integer_constraints c; 233 unsigned int amount; 234 235 if (ic_maybe_signed(tp, &a)) 236 return ic_any(tp); 237 238 if (b.smin == b.smax && b.smin >= 0 && b.smin < 64) 239 amount = (unsigned int)b.smin; 240 else if (b.umin == b.umax && b.umin < 64) 241 amount = (unsigned int)b.umin; 242 else 243 return ic_any(tp); 244 245 c.smin = INT64_MIN; 246 c.smax = INT64_MAX; 247 c.umin = 0; 248 c.umax = UINT64_MAX; 249 c.bset = a.bset << amount; 250 c.bclr = a.bclr << amount | (((uint64_t)1 << amount) - 1); 251 return c; 252 } 253 254 static integer_constraints 255 ic_shr(const type_t *tp, integer_constraints a, integer_constraints b) 256 { 257 integer_constraints c; 258 unsigned int amount; 259 260 if (ic_maybe_signed(tp, &a)) 261 return ic_any(tp); 262 263 if (b.smin == b.smax && b.smin >= 0 && b.smin < 64) 264 amount = (unsigned int)b.smin; 265 else if (b.umin == b.umax && b.umin < 64) 266 amount = (unsigned int)b.umin; 267 else 268 return ic_any(tp); 269 270 c.smin = INT64_MIN; 271 c.smax = INT64_MAX; 272 c.umin = 0; 273 c.umax = UINT64_MAX; 274 c.bset = a.bset >> amount; 275 c.bclr = a.bclr >> amount | ~(~(uint64_t)0 >> amount); 276 return c; 277 } 278 279 static integer_constraints 280 ic_cond(integer_constraints a, integer_constraints b) 281 { 282 integer_constraints c; 283 284 c.smin = a.smin < b.smin ? a.smin : b.smin; 285 c.smax = a.smax > b.smax ? a.smax : b.smax; 286 c.umin = a.umin < b.umin ? a.umin : b.umin; 287 c.umax = a.umax > b.umax ? a.umax : b.umax; 288 c.bset = a.bset | b.bset; 289 c.bclr = a.bclr & b.bclr; 290 return c; 291 } 292 293 static integer_constraints 294 ic_expr(const tnode_t *tn) 295 { 296 integer_constraints lc, rc; 297 298 lint_assert(is_integer(tn->tn_type->t_tspec)); 299 300 switch (tn->tn_op) { 301 case CON: 302 return ic_con(tn->tn_type, &tn->u.value); 303 case CVT: 304 if (!is_integer(tn->u.ops.left->tn_type->t_tspec)) 305 return ic_any(tn->tn_type); 306 lc = ic_expr(tn->u.ops.left); 307 return ic_cvt(tn->tn_type, tn->u.ops.left->tn_type, lc); 308 case DIV: 309 lc = ic_expr(before_conversion(tn->u.ops.left)); 310 rc = ic_expr(before_conversion(tn->u.ops.right)); 311 return ic_div(tn->tn_type, lc, rc); 312 case MOD: 313 lc = ic_expr(before_conversion(tn->u.ops.left)); 314 rc = ic_expr(before_conversion(tn->u.ops.right)); 315 return ic_mod(tn->tn_type, lc, rc); 316 case SHL: 317 lc = ic_expr(tn->u.ops.left); 318 rc = ic_expr(tn->u.ops.right); 319 return ic_shl(tn->tn_type, lc, rc); 320 case SHR: 321 lc = ic_expr(tn->u.ops.left); 322 rc = ic_expr(tn->u.ops.right); 323 return ic_shr(tn->tn_type, lc, rc); 324 case BITAND: 325 lc = ic_expr(tn->u.ops.left); 326 rc = ic_expr(tn->u.ops.right); 327 return ic_bitand(lc, rc); 328 case BITOR: 329 lc = ic_expr(tn->u.ops.left); 330 rc = ic_expr(tn->u.ops.right); 331 return ic_bitor(lc, rc); 332 case QUEST: 333 lc = ic_expr(tn->u.ops.right->u.ops.left); 334 rc = ic_expr(tn->u.ops.right->u.ops.right); 335 return ic_cond(lc, rc); 336 default: 337 return ic_any(tn->tn_type); 338 } 339 } 340 341 uint64_t 342 possible_bits(const tnode_t *tn) 343 { 344 return ~ic_expr(tn).bclr; 345 } 346 347 bool 348 attributes_contain(const attribute_list *attrs, const char *str) 349 { 350 for (size_t i = 0, n = attrs->len; i < n; i++) { 351 const attribute *attr = attrs->attrs + i; 352 if (attr->prefix == NULL && strcmp(attr->name, str) == 0) 353 return true; 354 } 355 return false; 356 } 357 358 /* Build 'pointer to tp', 'array of tp' or 'function returning tp'. */ 359 type_t * 360 block_derive_type(type_t *tp, tspec_t t) 361 { 362 363 type_t *tp2 = block_zero_alloc(sizeof(*tp2), "type"); 364 tp2->t_tspec = t; 365 tp2->t_subt = tp; 366 return tp2; 367 } 368 369 /* 370 * Derive 'pointer to tp' or 'function returning tp'. 371 * The memory is freed at the end of the current expression. 372 */ 373 type_t * 374 expr_derive_type(type_t *tp, tspec_t t) 375 { 376 377 type_t *tp2 = expr_zero_alloc(sizeof(*tp2), "type"); 378 tp2->t_tspec = t; 379 tp2->t_subt = tp; 380 return tp2; 381 } 382 383 /* Create an expression from a unary or binary operator and its operands. */ 384 static tnode_t * 385 build_op(op_t op, bool sys, type_t *type, tnode_t *ln, tnode_t *rn) 386 { 387 388 tnode_t *ntn = expr_alloc_tnode(); 389 ntn->tn_op = op; 390 ntn->tn_type = type; 391 ntn->tn_sys = sys; 392 ntn->u.ops.left = ln; 393 ntn->u.ops.right = rn; 394 395 if (op == INDIR || op == FSEL) { 396 lint_assert(ln->tn_type->t_tspec == PTR); 397 tspec_t t = ln->tn_type->t_subt->t_tspec; 398 ntn->tn_lvalue = t != FUNC && t != VOID; 399 } 400 401 return ntn; 402 } 403 404 tnode_t * 405 build_constant(type_t *tp, val_t *v) 406 { 407 408 tnode_t *n = expr_alloc_tnode(); 409 n->tn_op = CON; 410 n->tn_type = tp; 411 n->u.value = *v; 412 n->u.value.v_tspec = tp->t_tspec; 413 free(v); 414 return n; 415 } 416 417 static tnode_t * 418 build_integer_constant(tspec_t t, int64_t si) 419 { 420 421 tnode_t *n = expr_alloc_tnode(); 422 n->tn_op = CON; 423 n->tn_type = gettyp(t); 424 n->u.value.v_tspec = t; 425 n->u.value.v_unsigned_since_c90 = false; 426 n->u.value.v_char_constant = false; 427 n->u.value.u.integer = si; 428 return n; 429 } 430 431 static void 432 fallback_symbol(sym_t *sym) 433 { 434 435 if (Tflag && fallback_symbol_strict_bool(sym)) 436 return; 437 438 if (funcsym != NULL && (strcmp(sym->s_name, "__FUNCTION__") == 0 || 439 strcmp(sym->s_name, "__PRETTY_FUNCTION__") == 0)) { 440 /* __FUNCTION__/__PRETTY_FUNCTION__ is a GCC extension */ 441 gnuism(316); 442 goto return_function_name; 443 } 444 445 if (funcsym != NULL && strcmp(sym->s_name, "__func__") == 0) { 446 if (!allow_c99) 447 /* __func__ is a C99 feature */ 448 warning(317); 449 /* C11 6.4.2.2 */ 450 return_function_name: 451 sym->s_type = block_derive_type(gettyp(CHAR), ARRAY); 452 sym->s_type->t_const = true; 453 sym->s_type->u.dimension = (int)strlen(funcsym->s_name) + 1; 454 return; 455 } 456 457 /* '%s' undefined */ 458 error(99, sym->s_name); 459 } 460 461 /* 462 * Functions that are predeclared by GCC or other compilers can be called 463 * with arbitrary arguments. Since lint usually runs after a successful 464 * compilation, it's the compiler's job to catch any errors. 465 */ 466 bool 467 is_compiler_builtin(const char *name) 468 { 469 /* https://gcc.gnu.org/onlinedocs/gcc/C-Extensions.html */ 470 if (allow_gcc) { 471 if (strncmp(name, "__atomic_", 9) == 0 || 472 strncmp(name, "__builtin_", 10) == 0 || 473 strcmp(name, "alloca") == 0 || 474 /* obsolete but still in use, as of 2021 */ 475 strncmp(name, "__sync_", 7) == 0) 476 return true; 477 } 478 479 /* https://software.intel.com/sites/landingpage/IntrinsicsGuide/ */ 480 if (strncmp(name, "_mm_", 4) == 0) 481 return true; 482 483 return false; 484 } 485 486 /* https://gcc.gnu.org/onlinedocs/gcc/Integer-Overflow-Builtins.html */ 487 static bool 488 is_gcc_bool_builtin(const char *name) 489 { 490 return strncmp(name, "__builtin_", 10) == 0 && 491 (str_ends_with(name, "_overflow") || 492 str_ends_with(name, "_overflow_p")); 493 } 494 495 static void 496 build_name_call(sym_t *sym) 497 { 498 499 if (is_compiler_builtin(sym->s_name)) { 500 /* 501 * Do not warn about these, just assume that they are regular 502 * functions compatible with non-prototype calling conventions. 503 */ 504 if (allow_gcc && is_gcc_bool_builtin(sym->s_name)) 505 sym->s_type = gettyp(BOOL); 506 } else if (allow_c99) 507 /* function '%s' implicitly declared to return int */ 508 error(215, sym->s_name); 509 else if (!allow_trad) 510 /* function '%s' implicitly declared to return int */ 511 warning(215, sym->s_name); 512 513 /* XXX if !allow_c90, the symbol should be exported to level 0 */ 514 sym->s_type = block_derive_type(sym->s_type, FUNC); 515 } 516 517 /* Create a node for a name (symbol table entry). */ 518 tnode_t * 519 build_name(sym_t *sym, bool is_funcname) 520 { 521 522 if (sym->s_scl == NO_SCL && !in_gcc_attribute) { 523 sym->s_scl = EXTERN; 524 sym->s_def = DECL; 525 if (is_funcname) 526 build_name_call(sym); 527 else 528 fallback_symbol(sym); 529 } 530 531 lint_assert(sym->s_kind == SK_VCFT || sym->s_kind == SK_MEMBER); 532 533 tnode_t *n = expr_alloc_tnode(); 534 n->tn_type = sym->s_type; 535 if (sym->s_scl == BOOL_CONST) { 536 n->tn_op = CON; 537 n->u.value.v_tspec = BOOL; 538 n->u.value.v_unsigned_since_c90 = false; 539 n->u.value.v_char_constant = false; 540 n->u.value.u.integer = sym->u.s_bool_constant ? 1 : 0; 541 } else if (sym->s_scl == ENUM_CONST) { 542 n->tn_op = CON; 543 n->u.value.v_tspec = INT; /* ENUM is in n->tn_type */ 544 n->u.value.v_unsigned_since_c90 = false; 545 n->u.value.v_char_constant = false; 546 n->u.value.u.integer = sym->u.s_enum_constant; 547 } else { 548 n->tn_op = NAME; 549 n->u.sym = sym; 550 if (sym->s_kind == SK_VCFT && sym->s_type->t_tspec != FUNC) 551 n->tn_lvalue = true; 552 } 553 554 return n; 555 } 556 557 tnode_t * 558 build_string(buffer *lit) 559 { 560 size_t value_len = lit->len; 561 if (lit->data != NULL) { 562 quoted_iterator it = { .end = 0 }; 563 for (value_len = 0; quoted_next(lit, &it); value_len++) 564 continue; 565 } 566 567 type_t *tp = expr_zero_alloc(sizeof(*tp), "type"); 568 tp->t_tspec = ARRAY; 569 tp->t_subt = gettyp(lit->data != NULL ? CHAR : WCHAR_TSPEC); 570 tp->u.dimension = (int)(value_len + 1); 571 572 tnode_t *n = expr_alloc_tnode(); 573 n->tn_op = STRING; 574 n->tn_type = tp; 575 n->tn_lvalue = true; 576 577 n->u.str_literals = expr_zero_alloc(sizeof(*n->u.str_literals), "tnode.string"); 578 n->u.str_literals->len = lit->len; 579 580 if (lit->data != NULL) { 581 n->u.str_literals->data = expr_zero_alloc(lit->len + 1, 582 "tnode.string.data"); 583 (void)memcpy(n->u.str_literals->data, lit->data, lit->len + 1); 584 free(lit->data); 585 } 586 free(lit); 587 588 return n; 589 } 590 591 tnode_t * 592 build_generic_selection(const tnode_t *expr, 593 struct generic_association *sel) 594 { 595 tnode_t *default_result = NULL; 596 597 for (; sel != NULL; sel = sel->ga_prev) { 598 if (expr != NULL && 599 types_compatible(sel->ga_arg, expr->tn_type, 600 false, false, NULL)) 601 return sel->ga_result; 602 else if (sel->ga_arg == NULL) 603 default_result = sel->ga_result; 604 } 605 return default_result; 606 } 607 608 static bool 609 is_out_of_char_range(const tnode_t *tn) 610 { 611 return tn->tn_op == CON && 612 !tn->u.value.v_char_constant && 613 !(0 <= tn->u.value.u.integer && 614 tn->u.value.u.integer < 1 << (CHAR_SIZE - 1)); 615 } 616 617 static bool 618 check_nonportable_char_comparison(op_t op, 619 const tnode_t *ln, tspec_t lt, 620 const tnode_t *rn, tspec_t rt) 621 { 622 if (!(hflag || pflag)) 623 return true; 624 625 if (lt == CHAR && is_out_of_char_range(rn)) { 626 char buf[128]; 627 (void)snprintf(buf, sizeof(buf), "%s %d", 628 op_name(op), (int)rn->u.value.u.integer); 629 /* nonportable character comparison '%s' */ 630 warning(230, buf); 631 return false; 632 } 633 if (rt == CHAR && is_out_of_char_range(ln)) { 634 char buf[128]; 635 (void)snprintf(buf, sizeof(buf), "%d %s ?", 636 (int)ln->u.value.u.integer, op_name(op)); 637 /* nonportable character comparison '%s' */ 638 warning(230, buf); 639 return false; 640 } 641 return true; 642 } 643 644 static void 645 check_integer_comparison(op_t op, tnode_t *ln, tnode_t *rn) 646 { 647 648 tspec_t lt = ln->tn_type->t_tspec; 649 tspec_t rt = rn->tn_type->t_tspec; 650 651 if (ln->tn_op != CON && rn->tn_op != CON) 652 return; 653 654 if (!is_integer(lt) || !is_integer(rt)) 655 return; 656 657 if (any_query_enabled && !in_system_header) { 658 if (lt == CHAR && rn->tn_op == CON && 659 !rn->u.value.v_char_constant) { 660 /* comparison '%s' of 'char' with plain integer %d */ 661 query_message(14, 662 op_name(op), (int)rn->u.value.u.integer); 663 } 664 if (rt == CHAR && ln->tn_op == CON && 665 !ln->u.value.v_char_constant) { 666 /* comparison '%s' of 'char' with plain integer %d */ 667 query_message(14, 668 op_name(op), (int)ln->u.value.u.integer); 669 } 670 } 671 672 if (!check_nonportable_char_comparison(op, ln, lt, rn, rt)) 673 return; 674 675 if (is_uinteger(lt) && !is_uinteger(rt) && 676 rn->tn_op == CON && rn->u.value.u.integer <= 0) { 677 if (rn->u.value.u.integer < 0) { 678 /* operator '%s' compares '%s' with '%s' */ 679 warning(162, op_name(op), 680 type_name(ln->tn_type), "negative constant"); 681 } else if (op == LT || op == GE) 682 /* operator '%s' compares '%s' with '%s' */ 683 warning(162, op_name(op), type_name(ln->tn_type), "0"); 684 return; 685 } 686 if (is_uinteger(rt) && !is_uinteger(lt) && 687 ln->tn_op == CON && ln->u.value.u.integer <= 0) { 688 if (ln->u.value.u.integer < 0) { 689 /* operator '%s' compares '%s' with '%s' */ 690 warning(162, op_name(op), 691 "negative constant", type_name(rn->tn_type)); 692 } else if (op == GT || op == LE) 693 /* operator '%s' compares '%s' with '%s' */ 694 warning(162, op_name(op), "0", type_name(rn->tn_type)); 695 return; 696 } 697 } 698 699 static const tspec_t arith_rank[] = { 700 LDOUBLE, DOUBLE, FLOAT, 701 #ifdef INT128_SIZE 702 UINT128, INT128, 703 #endif 704 ULLONG, LLONG, 705 ULONG, LONG, 706 UINT, INT, 707 }; 708 709 /* Keep unsigned in traditional C */ 710 static tspec_t 711 usual_arithmetic_conversion_trad(tspec_t lt, tspec_t rt) 712 { 713 714 size_t i; 715 for (i = 0; arith_rank[i] != INT; i++) 716 if (lt == arith_rank[i] || rt == arith_rank[i]) 717 break; 718 719 tspec_t t = arith_rank[i]; 720 if (is_uinteger(lt) || is_uinteger(rt)) 721 if (is_integer(t) && !is_uinteger(t)) 722 return unsigned_type(t); 723 return t; 724 } 725 726 static tspec_t 727 usual_arithmetic_conversion_c90(tspec_t lt, tspec_t rt) 728 { 729 730 if (lt == rt) 731 return lt; 732 733 if (lt == LCOMPLEX || rt == LCOMPLEX) 734 return LCOMPLEX; 735 if (lt == DCOMPLEX || rt == DCOMPLEX) 736 return DCOMPLEX; 737 if (lt == FCOMPLEX || rt == FCOMPLEX) 738 return FCOMPLEX; 739 if (lt == LDOUBLE || rt == LDOUBLE) 740 return LDOUBLE; 741 if (lt == DOUBLE || rt == DOUBLE) 742 return DOUBLE; 743 if (lt == FLOAT || rt == FLOAT) 744 return FLOAT; 745 746 if (size_in_bits(lt) > size_in_bits(rt)) 747 return lt; 748 if (size_in_bits(lt) < size_in_bits(rt)) 749 return rt; 750 751 size_t i; 752 for (i = 3; arith_rank[i] != INT; i++) 753 if (arith_rank[i] == lt || arith_rank[i] == rt) 754 break; 755 if ((is_uinteger(lt) || is_uinteger(rt)) && 756 !is_uinteger(arith_rank[i])) 757 i--; 758 return arith_rank[i]; 759 } 760 761 static tnode_t * 762 apply_usual_arithmetic_conversions(op_t op, tnode_t *tn, tspec_t t) 763 { 764 type_t *ntp = expr_dup_type(tn->tn_type); 765 ntp->t_tspec = t; 766 if (tn->tn_op != CON) { 767 /* usual arithmetic conversion for '%s' from '%s' to '%s' */ 768 query_message(4, op_name(op), 769 type_name(tn->tn_type), type_name(ntp)); 770 } 771 return convert(op, 0, ntp, tn); 772 } 773 774 /* 775 * Apply the "usual arithmetic conversions" (C99 6.3.1.8), which gives both 776 * operands the same type. 777 */ 778 static void 779 balance(op_t op, tnode_t **lnp, tnode_t **rnp) 780 { 781 782 tspec_t lt = (*lnp)->tn_type->t_tspec; 783 tspec_t rt = (*rnp)->tn_type->t_tspec; 784 if (!is_arithmetic(lt) || !is_arithmetic(rt)) 785 return; 786 787 tspec_t t = allow_c90 788 ? usual_arithmetic_conversion_c90(lt, rt) 789 : usual_arithmetic_conversion_trad(lt, rt); 790 791 if (modtab[op].m_comparison 792 && is_integer(lt) && (*lnp)->tn_op != CON 793 && is_floating(t) && (*rnp)->tn_op == CON) 794 /* comparing integer '%s' to floating point constant %Lg */ 795 warning(379, type_name((*lnp)->tn_type), 796 (*rnp)->u.value.u.floating); 797 798 if (t != lt) 799 *lnp = apply_usual_arithmetic_conversions(op, *lnp, t); 800 if (t != rt) 801 *rnp = apply_usual_arithmetic_conversions(op, *rnp, t); 802 803 if (is_integer(t)) { 804 unsigned lw = width_in_bits((*lnp)->tn_type); 805 unsigned rw = width_in_bits((*rnp)->tn_type); 806 if (lw < rw) 807 *lnp = convert(NOOP, 0, (*rnp)->tn_type, *lnp); 808 if (rw < lw) 809 *rnp = convert(NOOP, 0, (*lnp)->tn_type, *rnp); 810 } 811 } 812 813 static tnode_t * 814 build_address(bool sys, tnode_t *tn, bool force) 815 { 816 tspec_t t; 817 818 if (!force && ((t = tn->tn_type->t_tspec) == ARRAY || t == FUNC)) { 819 if (!allow_c90) 820 /* '&' before array or function: ignored */ 821 warning(127); 822 return tn; 823 } 824 825 /* eliminate '&*' */ 826 if (tn->tn_op == INDIR && 827 tn->u.ops.left->tn_type->t_tspec == PTR && 828 tn->u.ops.left->tn_type->t_subt == tn->tn_type) { 829 return tn->u.ops.left; 830 } 831 832 return build_op(ADDR, sys, expr_derive_type(tn->tn_type, PTR), 833 tn, NULL); 834 } 835 836 static uint64_t 837 fold_unsigned_integer(op_t op, uint64_t l, uint64_t r, 838 uint64_t max_value, bool *overflow) 839 { 840 switch (op) { 841 case COMPL: 842 return ~l & max_value; 843 case UPLUS: 844 return +l; 845 case UMINUS: 846 return -l & max_value; 847 case MULT: 848 *overflow = r > 0 && l > max_value / r; 849 return l * r; 850 case DIV: 851 if (r == 0) { 852 /* division by 0 */ 853 error(139); 854 return max_value; 855 } 856 return l / r; 857 case MOD: 858 if (r == 0) { 859 /* modulus by 0 */ 860 error(140); 861 return 0; 862 } 863 return l % r; 864 case PLUS: 865 *overflow = l > max_value - r; 866 return l + r; 867 case MINUS: 868 *overflow = l < r; 869 return l - r; 870 case SHL: 871 /* TODO: warn about out-of-bounds 'r'. */ 872 /* TODO: warn about overflow. */ 873 return l << (r & 63); 874 case SHR: 875 /* TODO: warn about out-of-bounds 'r'. */ 876 return l >> (r & 63); 877 case LT: 878 return l < r ? 1 : 0; 879 case LE: 880 return l <= r ? 1 : 0; 881 case GT: 882 return l > r ? 1 : 0; 883 case GE: 884 return l >= r ? 1 : 0; 885 case EQ: 886 return l == r ? 1 : 0; 887 case NE: 888 return l != r ? 1 : 0; 889 case BITAND: 890 return l & r; 891 case BITXOR: 892 return l ^ r; 893 case BITOR: 894 return l | r; 895 default: 896 lint_assert(/*CONSTCOND*/false); 897 /* NOTREACHED */ 898 } 899 } 900 901 static int64_t 902 fold_signed_integer(op_t op, int64_t l, int64_t r, 903 int64_t min_value, int64_t max_value, bool *overflow) 904 { 905 switch (op) { 906 case COMPL: 907 return ~l; 908 case UPLUS: 909 return +l; 910 case UMINUS: 911 *overflow = l == min_value; 912 return *overflow ? l : -l; 913 case MULT:; 914 uint64_t al = l >= 0 ? (uint64_t)l : -(uint64_t)l; 915 uint64_t ar = r >= 0 ? (uint64_t)r : -(uint64_t)r; 916 bool neg = (l >= 0) != (r >= 0); 917 uint64_t max_prod = (uint64_t)max_value + (neg ? 1 : 0); 918 if (al > 0 && ar > max_prod / al) { 919 *overflow = true; 920 return neg ? min_value : max_value; 921 } 922 return l * r; 923 case DIV: 924 if (r == 0) { 925 /* division by 0 */ 926 error(139); 927 return max_value; 928 } 929 if (l == min_value && r == -1) { 930 *overflow = true; 931 return l; 932 } 933 return l / r; 934 case MOD: 935 if (r == 0) { 936 /* modulus by 0 */ 937 error(140); 938 return 0; 939 } 940 if (l == min_value && r == -1) { 941 *overflow = true; 942 return 0; 943 } 944 return l % r; 945 case PLUS: 946 if (r > 0 && l > max_value - r) { 947 *overflow = true; 948 return max_value; 949 } 950 if (r < 0 && l < min_value - r) { 951 *overflow = true; 952 return min_value; 953 } 954 return l + r; 955 case MINUS: 956 if (r > 0 && l < min_value + r) { 957 *overflow = true; 958 return min_value; 959 } 960 if (r < 0 && l > max_value + r) { 961 *overflow = true; 962 return max_value; 963 } 964 return l - r; 965 case SHL: 966 /* TODO: warn about out-of-bounds 'r'. */ 967 /* TODO: warn about overflow. */ 968 return l << (r & 63); 969 case SHR: 970 /* TODO: warn about out-of-bounds 'r'. */ 971 if (l < 0) 972 return (int64_t)~(~(uint64_t)l >> (r & 63)); 973 return (int64_t)((uint64_t)l >> (r & 63)); 974 case LT: 975 return l < r ? 1 : 0; 976 case LE: 977 return l <= r ? 1 : 0; 978 case GT: 979 return l > r ? 1 : 0; 980 case GE: 981 return l >= r ? 1 : 0; 982 case EQ: 983 return l == r ? 1 : 0; 984 case NE: 985 return l != r ? 1 : 0; 986 case BITAND: 987 return l & r; 988 case BITXOR: 989 return l ^ r; 990 case BITOR: 991 return l | r; 992 default: 993 lint_assert(/*CONSTCOND*/false); 994 /* NOTREACHED */ 995 } 996 } 997 998 static tnode_t * 999 fold_constant_integer(tnode_t *tn) 1000 { 1001 1002 lint_assert(has_operands(tn)); 1003 tspec_t t = tn->u.ops.left->tn_type->t_tspec; 1004 int64_t l = tn->u.ops.left->u.value.u.integer; 1005 int64_t r = is_binary(tn) ? tn->u.ops.right->u.value.u.integer : 0; 1006 uint64_t mask = value_bits(size_in_bits(t)); 1007 1008 int64_t res; 1009 bool overflow = false; 1010 if (!is_integer(t) || is_uinteger(t)) { 1011 uint64_t u_res = fold_unsigned_integer(tn->tn_op, 1012 (uint64_t)l, (uint64_t)r, mask, &overflow); 1013 if (u_res > mask) 1014 overflow = true; 1015 res = (int64_t)u_res; 1016 if (overflow && hflag) { 1017 char buf[128]; 1018 if (is_binary(tn)) { 1019 snprintf(buf, sizeof(buf), "%ju %s %ju", 1020 (uintmax_t)l, op_name(tn->tn_op), 1021 (uintmax_t)r); 1022 } else { 1023 snprintf(buf, sizeof(buf), "%s%ju", 1024 op_name(tn->tn_op), (uintmax_t)l); 1025 } 1026 /* '%s' overflows '%s' */ 1027 warning(141, buf, type_name(tn->tn_type)); 1028 } 1029 } else { 1030 int64_t max_value = (int64_t)(mask >> 1); 1031 int64_t min_value = -max_value - 1; 1032 res = fold_signed_integer(tn->tn_op, 1033 l, r, min_value, max_value, &overflow); 1034 if (res < min_value || res > max_value) 1035 overflow = true; 1036 if (overflow && hflag) { 1037 char buf[128]; 1038 if (is_binary(tn)) { 1039 snprintf(buf, sizeof(buf), "%jd %s %jd", 1040 (intmax_t)l, op_name(tn->tn_op), 1041 (intmax_t)r); 1042 } else if (tn->tn_op == UMINUS && l < 0) { 1043 snprintf(buf, sizeof(buf), "-(%jd)", 1044 (intmax_t)l); 1045 } else { 1046 snprintf(buf, sizeof(buf), "%s%jd", 1047 op_name(tn->tn_op), (intmax_t)l); 1048 } 1049 /* '%s' overflows '%s' */ 1050 warning(141, buf, type_name(tn->tn_type)); 1051 } 1052 } 1053 1054 val_t *v = xcalloc(1, sizeof(*v)); 1055 v->v_tspec = tn->tn_type->t_tspec; 1056 v->u.integer = convert_integer(res, t, size_in_bits(t)); 1057 1058 tnode_t *cn = build_constant(tn->tn_type, v); 1059 if (tn->u.ops.left->tn_system_dependent) 1060 cn->tn_system_dependent = true; 1061 if (is_binary(tn) && tn->u.ops.right->tn_system_dependent) 1062 cn->tn_system_dependent = true; 1063 1064 return cn; 1065 } 1066 1067 static tnode_t * 1068 build_struct_access(op_t op, bool sys, tnode_t *ln, tnode_t *rn) 1069 { 1070 1071 lint_assert(rn->tn_op == NAME); 1072 lint_assert(is_member(rn->u.sym)); 1073 1074 bool lvalue = op == ARROW || ln->tn_lvalue; 1075 1076 if (op == POINT) 1077 ln = build_address(sys, ln, true); 1078 else if (ln->tn_type->t_tspec != PTR) { 1079 lint_assert(!allow_c90); 1080 lint_assert(is_integer(ln->tn_type->t_tspec)); 1081 ln = convert(NOOP, 0, expr_derive_type(gettyp(VOID), PTR), ln); 1082 } 1083 1084 tnode_t *ctn = build_integer_constant(PTRDIFF_TSPEC, 1085 rn->u.sym->u.s_member.sm_offset_in_bits / CHAR_SIZE); 1086 1087 type_t *ptr_tp = expr_derive_type(rn->tn_type, PTR); 1088 tnode_t *ntn = build_op(PLUS, sys, ptr_tp, ln, ctn); 1089 if (ln->tn_op == CON) 1090 ntn = fold_constant_integer(ntn); 1091 1092 op_t nop = rn->tn_type->t_bitfield ? FSEL : INDIR; 1093 ntn = build_op(nop, sys, ntn->tn_type->t_subt, ntn, NULL); 1094 if (!lvalue) 1095 ntn->tn_lvalue = false; 1096 1097 return ntn; 1098 } 1099 1100 /* 1101 * Get the size in bytes of type tp->t_subt, as a constant expression of type 1102 * ptrdiff_t as seen from the target platform. 1103 */ 1104 static tnode_t * 1105 subt_size_in_bytes(type_t *tp) 1106 { 1107 1108 lint_assert(tp->t_tspec == PTR); 1109 tp = tp->t_subt; 1110 1111 int elem = 1; 1112 while (tp->t_tspec == ARRAY) { 1113 elem *= tp->u.dimension; 1114 tp = tp->t_subt; 1115 } 1116 1117 int elsz_in_bits = 0; 1118 switch (tp->t_tspec) { 1119 case FUNC: 1120 /* pointer to function is not allowed here */ 1121 error(110); 1122 break; 1123 case VOID: 1124 /* cannot do pointer arithmetic on operand of unknown size */ 1125 gnuism(136); 1126 break; 1127 case STRUCT: 1128 case UNION: 1129 if ((elsz_in_bits = (int)tp->u.sou->sou_size_in_bits) == 0) 1130 /* cannot do pointer arithmetic on operand of ... */ 1131 error(136); 1132 break; 1133 case ENUM: 1134 if (is_incomplete(tp)) 1135 /* cannot do pointer arithmetic on operand of ... */ 1136 warning(136); 1137 /* FALLTHROUGH */ 1138 default: 1139 if ((elsz_in_bits = size_in_bits(tp->t_tspec)) == 0) 1140 /* cannot do pointer arithmetic on operand of ... */ 1141 error(136); 1142 else 1143 lint_assert(elsz_in_bits != -1); 1144 break; 1145 } 1146 1147 if (elem == 0 && elsz_in_bits != 0) 1148 /* cannot do pointer arithmetic on operand of unknown size */ 1149 error(136); 1150 1151 if (elsz_in_bits == 0) 1152 elsz_in_bits = CHAR_SIZE; 1153 1154 return build_integer_constant(PTRDIFF_TSPEC, 1155 (int64_t)(elem * elsz_in_bits / CHAR_SIZE)); 1156 } 1157 1158 static tnode_t * 1159 build_prepost_incdec(op_t op, bool sys, tnode_t *ln) 1160 { 1161 1162 lint_assert(ln != NULL); 1163 tnode_t *cn = ln->tn_type->t_tspec == PTR 1164 ? subt_size_in_bytes(ln->tn_type) 1165 : build_integer_constant(INT, 1); 1166 return build_op(op, sys, ln->tn_type, ln, cn); 1167 } 1168 1169 static void 1170 check_enum_array_index(const tnode_t *ln, const tnode_t *rn) 1171 { 1172 1173 if (ln->tn_op != ADDR || ln->u.ops.left->tn_op != NAME) 1174 return; 1175 1176 const type_t *ltp = ln->u.ops.left->tn_type; 1177 if (ltp->t_tspec != ARRAY || ltp->t_incomplete_array) 1178 return; 1179 1180 if (rn->tn_op != CVT || !rn->tn_type->t_is_enum) 1181 return; 1182 if (rn->u.ops.left->tn_op != LOAD) 1183 return; 1184 1185 const type_t *rtp = rn->u.ops.left->tn_type; 1186 const sym_t *ec = rtp->u.enumer->en_first_enumerator; 1187 const sym_t *max_ec = ec; 1188 lint_assert(ec != NULL); 1189 for (ec = ec->s_next; ec != NULL; ec = ec->s_next) 1190 if (ec->u.s_enum_constant > max_ec->u.s_enum_constant) 1191 max_ec = ec; 1192 1193 int64_t max_enum_value = max_ec->u.s_enum_constant; 1194 lint_assert(INT_MIN <= max_enum_value && max_enum_value <= INT_MAX); 1195 1196 int max_array_index = ltp->u.dimension - 1; 1197 if (max_enum_value == max_array_index) 1198 return; 1199 1200 if (max_enum_value == max_array_index + 1 && 1201 (strstr(max_ec->s_name, "MAX") != NULL || 1202 strstr(max_ec->s_name, "max") != NULL || 1203 strstr(max_ec->s_name, "NUM") != NULL || 1204 strstr(max_ec->s_name, "num") != NULL)) 1205 return; 1206 1207 /* maximum value %d of '%s' does not match maximum array index %d */ 1208 warning(348, (int)max_enum_value, type_name(rtp), max_array_index); 1209 print_previous_declaration(max_ec); 1210 } 1211 1212 static tnode_t * 1213 build_plus_minus(op_t op, bool sys, tnode_t *ln, tnode_t *rn) 1214 { 1215 1216 if (rn->tn_type->t_tspec == PTR && is_integer(ln->tn_type->t_tspec)) { 1217 tnode_t *tmp = ln; 1218 ln = rn; 1219 rn = tmp; 1220 /* pointer addition has integer on the left-hand side */ 1221 query_message(5); 1222 } 1223 1224 /* pointer +- integer */ 1225 tspec_t lt = ln->tn_type->t_tspec; 1226 tspec_t rt = rn->tn_type->t_tspec; 1227 if (lt == PTR && rt != PTR) { 1228 lint_assert(is_integer(rt)); 1229 1230 check_ctype_macro_invocation(ln, rn); 1231 check_enum_array_index(ln, rn); 1232 1233 tnode_t *elsz = subt_size_in_bytes(ln->tn_type); 1234 tspec_t szt = elsz->tn_type->t_tspec; 1235 if (rt != szt && rt != unsigned_type(szt)) 1236 rn = convert(NOOP, 0, elsz->tn_type, rn); 1237 1238 tnode_t *prod = build_op(MULT, sys, rn->tn_type, rn, elsz); 1239 if (rn->tn_op == CON) 1240 prod = fold_constant_integer(prod); 1241 1242 return build_op(op, sys, ln->tn_type, ln, prod); 1243 } 1244 1245 /* pointer - pointer */ 1246 if (rt == PTR) { 1247 lint_assert(lt == PTR); 1248 lint_assert(op == MINUS); 1249 1250 type_t *ptrdiff = gettyp(PTRDIFF_TSPEC); 1251 tnode_t *raw_diff = build_op(op, sys, ptrdiff, ln, rn); 1252 if (ln->tn_op == CON && rn->tn_op == CON) 1253 raw_diff = fold_constant_integer(raw_diff); 1254 1255 tnode_t *elsz = subt_size_in_bytes(ln->tn_type); 1256 balance(NOOP, &raw_diff, &elsz); 1257 1258 return build_op(DIV, sys, ptrdiff, raw_diff, elsz); 1259 } 1260 1261 return build_op(op, sys, ln->tn_type, ln, rn); 1262 } 1263 1264 static tnode_t * 1265 build_bit_shift(op_t op, bool sys, tnode_t *ln, tnode_t *rn) 1266 { 1267 1268 if (!allow_c90 && rn->tn_type->t_tspec != INT) 1269 // XXX: C1978 7.5 says: "Both [operators] perform the usual 1270 // arithmetic conversions on their operands." 1271 // TODO: Add a test to exercise this part of the code. 1272 rn = convert(NOOP, 0, gettyp(INT), rn); 1273 return build_op(op, sys, ln->tn_type, ln, rn); 1274 } 1275 1276 static bool 1277 is_null_pointer(const tnode_t *tn) 1278 { 1279 tspec_t t = tn->tn_type->t_tspec; 1280 1281 // TODO: Investigate how other pointers are stored, in particular, 1282 // whether a pointer constant can have a non-zero value. 1283 // If not, simplify the code below. 1284 return ((t == PTR && tn->tn_type->t_subt->t_tspec == VOID) 1285 || is_integer(t)) 1286 && (tn->tn_op == CON && tn->u.value.u.integer == 0); 1287 } 1288 1289 /* Return a type based on tp1, with added qualifiers from tp2. */ 1290 static type_t * 1291 merge_qualifiers(type_t *tp1, const type_t *tp2) 1292 { 1293 1294 lint_assert(tp1->t_tspec == PTR); 1295 lint_assert(tp2->t_tspec == PTR); 1296 1297 bool c1 = tp1->t_subt->t_const; 1298 bool c2 = tp2->t_subt->t_const; 1299 bool v1 = tp1->t_subt->t_volatile; 1300 bool v2 = tp2->t_subt->t_volatile; 1301 1302 if (c1 == (c1 | c2) && v1 == (v1 | v2)) 1303 return tp1; 1304 1305 type_t *nstp = expr_dup_type(tp1->t_subt); 1306 nstp->t_const |= c2; 1307 nstp->t_volatile |= v2; 1308 1309 type_t *ntp = expr_dup_type(tp1); 1310 ntp->t_subt = nstp; 1311 return ntp; 1312 } 1313 1314 /* See C99 6.5.15 "Conditional operator". */ 1315 static tnode_t * 1316 build_colon(bool sys, tnode_t *ln, tnode_t *rn) 1317 { 1318 tspec_t lt = ln->tn_type->t_tspec; 1319 tspec_t rt = rn->tn_type->t_tspec; 1320 1321 type_t *tp; 1322 if (is_arithmetic(lt) && is_arithmetic(rt)) 1323 /* The operands were already balanced in build_binary. */ 1324 tp = ln->tn_type; 1325 else if (lt == BOOL && rt == BOOL) 1326 tp = ln->tn_type; 1327 else if (lt == VOID || rt == VOID) 1328 tp = gettyp(VOID); 1329 else if (is_struct_or_union(lt)) { 1330 lint_assert(is_struct_or_union(rt)); 1331 lint_assert(ln->tn_type->u.sou == rn->tn_type->u.sou); 1332 if (is_incomplete(ln->tn_type)) { 1333 /* unknown operand size, op '%s' */ 1334 error(138, op_name(COLON)); 1335 return NULL; 1336 } 1337 tp = ln->tn_type; 1338 } else if (lt == PTR && is_integer(rt)) { 1339 if (rt != PTRDIFF_TSPEC) 1340 rn = convert(NOOP, 0, gettyp(PTRDIFF_TSPEC), rn); 1341 tp = ln->tn_type; 1342 } else if (rt == PTR && is_integer(lt)) { 1343 if (lt != PTRDIFF_TSPEC) 1344 ln = convert(NOOP, 0, gettyp(PTRDIFF_TSPEC), ln); 1345 tp = rn->tn_type; 1346 } else if (lt == PTR && is_null_pointer(rn)) 1347 tp = merge_qualifiers(ln->tn_type, rn->tn_type); 1348 else if (rt == PTR && is_null_pointer(ln)) 1349 tp = merge_qualifiers(rn->tn_type, ln->tn_type); 1350 else if (lt == PTR && ln->tn_type->t_subt->t_tspec == VOID) 1351 tp = merge_qualifiers(ln->tn_type, rn->tn_type); 1352 else if (rt == PTR && rn->tn_type->t_subt->t_tspec == VOID) 1353 tp = merge_qualifiers(rn->tn_type, ln->tn_type); 1354 else { 1355 /* 1356 * XXX For now we simply take the left type. This is probably 1357 * wrong, if one type contains a function prototype and the 1358 * other one, at the same place, only an old-style declaration. 1359 */ 1360 tp = merge_qualifiers(ln->tn_type, rn->tn_type); 1361 } 1362 1363 return build_op(COLON, sys, tp, ln, rn); 1364 } 1365 1366 /* TODO: check for varargs */ 1367 static bool 1368 is_cast_redundant(const tnode_t *tn) 1369 { 1370 const type_t *ntp = tn->tn_type, *otp = tn->u.ops.left->tn_type; 1371 tspec_t nt = ntp->t_tspec, ot = otp->t_tspec; 1372 1373 if (nt == BOOL || ot == BOOL) 1374 return nt == BOOL && ot == BOOL; 1375 1376 if (is_integer(nt) && is_integer(ot)) { 1377 unsigned int nw = width_in_bits(ntp), ow = width_in_bits(otp); 1378 if (is_uinteger(nt) == is_uinteger(ot)) 1379 return nw >= ow; 1380 return is_uinteger(ot) && nw > ow; 1381 } 1382 1383 if (is_complex(nt) || is_complex(ot)) 1384 return is_complex(nt) && is_complex(ot) && 1385 size_in_bits(nt) >= size_in_bits(ot); 1386 1387 if (is_floating(nt) && is_floating(ot)) 1388 return size_in_bits(nt) >= size_in_bits(ot); 1389 1390 if (nt == PTR && ot == PTR) { 1391 if (!ntp->t_subt->t_const && otp->t_subt->t_const) 1392 return false; 1393 if (!ntp->t_subt->t_volatile && otp->t_subt->t_volatile) 1394 return false; 1395 1396 if (ntp->t_subt->t_tspec == VOID || 1397 otp->t_subt->t_tspec == VOID || 1398 types_compatible(ntp->t_subt, otp->t_subt, 1399 false, false, NULL)) 1400 return true; 1401 } 1402 1403 return false; 1404 } 1405 1406 static bool 1407 is_assignment(op_t op) 1408 { 1409 1410 return op == ASSIGN || 1411 op == MULASS || 1412 op == DIVASS || 1413 op == MODASS || 1414 op == ADDASS || 1415 op == SUBASS || 1416 op == SHLASS || 1417 op == SHRASS || 1418 op == ANDASS || 1419 op == XORASS || 1420 op == ORASS || 1421 op == RETURN || 1422 op == INIT; 1423 } 1424 1425 static tnode_t * 1426 build_assignment(op_t op, bool sys, tnode_t *ln, tnode_t *rn) 1427 { 1428 1429 tspec_t lt = ln->tn_type->t_tspec; 1430 tspec_t rt = rn->tn_type->t_tspec; 1431 1432 if (any_query_enabled && is_assignment(rn->tn_op)) { 1433 /* chained assignment with '%s' and '%s' */ 1434 query_message(10, op_name(op), op_name(rn->tn_op)); 1435 } 1436 1437 if ((op == ADDASS || op == SUBASS) && lt == PTR) { 1438 lint_assert(is_integer(rt)); 1439 tnode_t *ctn = subt_size_in_bytes(ln->tn_type); 1440 if (rn->tn_type->t_tspec != ctn->tn_type->t_tspec) 1441 rn = convert(NOOP, 0, ctn->tn_type, rn); 1442 rn = build_op(MULT, sys, rn->tn_type, rn, ctn); 1443 if (rn->u.ops.left->tn_op == CON) 1444 rn = fold_constant_integer(rn); 1445 } 1446 1447 if ((op == ASSIGN || op == RETURN || op == INIT) && 1448 (lt == STRUCT || rt == STRUCT)) { 1449 lint_assert(lt == rt); 1450 lint_assert(ln->tn_type->u.sou == rn->tn_type->u.sou); 1451 if (is_incomplete(ln->tn_type)) { 1452 if (op == RETURN) 1453 /* cannot return incomplete type */ 1454 error(212); 1455 else 1456 /* unknown operand size, op '%s' */ 1457 error(138, op_name(op)); 1458 return NULL; 1459 } 1460 } 1461 1462 if (op == SHLASS && hflag && allow_trad && allow_c90 1463 && portable_rank_cmp(lt, rt) < 0) 1464 /* semantics of '%s' change in C90; ... */ 1465 warning(118, "<<="); 1466 1467 if (op != SHLASS && op != SHRASS 1468 && (op == ASSIGN || lt != PTR) 1469 && (lt != rt || (ln->tn_type->t_bitfield && rn->tn_op == CON))) { 1470 rn = convert(op, 0, ln->tn_type, rn); 1471 rt = lt; 1472 } 1473 1474 if (is_query_enabled[20] 1475 && lt == PTR && ln->tn_type->t_subt->t_tspec != VOID 1476 && rt == PTR && rn->tn_type->t_subt->t_tspec == VOID 1477 && !is_null_pointer(rn)) 1478 /* implicit narrowing conversion from void ... */ 1479 query_message(20, type_name(ln->tn_type)); 1480 1481 if (any_query_enabled && rn->tn_op == CVT && rn->tn_cast && 1482 types_compatible(ln->tn_type, rn->tn_type, false, false, NULL) && 1483 is_cast_redundant(rn)) { 1484 /* redundant cast from '%s' to '%s' before assignment */ 1485 query_message(7, type_name(rn->u.ops.left->tn_type), 1486 type_name(rn->tn_type)); 1487 } 1488 1489 return build_op(op, sys, ln->tn_type, ln, rn); 1490 } 1491 1492 static tnode_t * 1493 build_real_imag(op_t op, bool sys, tnode_t *ln) 1494 { 1495 1496 lint_assert(ln != NULL); 1497 if (ln->tn_op == NAME) { 1498 /* 1499 * This may be too much, but it avoids wrong warnings. See 1500 * d_c99_complex_split.c. 1501 */ 1502 mark_as_used(ln->u.sym, false, false); 1503 mark_as_set(ln->u.sym); 1504 } 1505 1506 tspec_t t; 1507 switch (ln->tn_type->t_tspec) { 1508 case LCOMPLEX: 1509 t = LDOUBLE; 1510 break; 1511 case DCOMPLEX: 1512 t = DOUBLE; 1513 break; 1514 case FCOMPLEX: 1515 t = FLOAT; 1516 break; 1517 default: 1518 /* '__%s__' is illegal for type '%s' */ 1519 error(276, op == REAL ? "real" : "imag", 1520 type_name(ln->tn_type)); 1521 return NULL; 1522 } 1523 1524 tnode_t *ntn = build_op(op, sys, gettyp(t), ln, NULL); 1525 ntn->tn_lvalue = true; 1526 return ntn; 1527 } 1528 1529 static bool 1530 is_confusing_precedence(op_t op, op_t lop, bool lparen, op_t rop, bool rparen) 1531 { 1532 1533 if (op == SHL || op == SHR) { 1534 if (!lparen && (lop == PLUS || lop == MINUS)) 1535 return true; 1536 if (!rparen && (rop == PLUS || rop == MINUS)) 1537 return true; 1538 return false; 1539 } 1540 1541 if (op == LOGOR) { 1542 if (!lparen && lop == LOGAND) 1543 return true; 1544 if (!rparen && rop == LOGAND) 1545 return true; 1546 return false; 1547 } 1548 1549 lint_assert(op == BITAND || op == BITXOR || op == BITOR); 1550 if (!lparen && lop != op) { 1551 if (lop == PLUS || lop == MINUS) 1552 return true; 1553 if (lop == BITAND || lop == BITXOR) 1554 return true; 1555 } 1556 if (!rparen && rop != op) { 1557 if (rop == PLUS || rop == MINUS) 1558 return true; 1559 if (rop == BITAND || rop == BITXOR) 1560 return true; 1561 } 1562 return false; 1563 } 1564 1565 /* 1566 * Print a warning if the given node has operands which should be 1567 * parenthesized. 1568 * 1569 * XXX Does not work if an operand is a constant expression. Constant 1570 * expressions are already folded. 1571 */ 1572 static void 1573 check_precedence_confusion(tnode_t *tn) 1574 { 1575 tnode_t *ln, *rn; 1576 1577 if (!hflag) 1578 return; 1579 1580 debug_node(tn); 1581 1582 lint_assert(is_binary(tn)); 1583 for (ln = tn->u.ops.left; ln->tn_op == CVT; ln = ln->u.ops.left) 1584 continue; 1585 for (rn = tn->u.ops.right; rn->tn_op == CVT; rn = rn->u.ops.left) 1586 continue; 1587 1588 if (is_confusing_precedence(tn->tn_op, 1589 ln->tn_op, ln->tn_parenthesized, 1590 rn->tn_op, rn->tn_parenthesized)) { 1591 /* precedence confusion possible: parenthesize! */ 1592 warning(169); 1593 } 1594 } 1595 1596 static tnode_t * 1597 fold_constant_compare_zero(tnode_t *tn) 1598 { 1599 1600 val_t *v = xcalloc(1, sizeof(*v)); 1601 v->v_tspec = tn->tn_type->t_tspec; 1602 lint_assert(v->v_tspec == INT || (Tflag && v->v_tspec == BOOL)); 1603 1604 lint_assert(has_operands(tn)); 1605 bool l = constant_is_nonzero(tn->u.ops.left); 1606 bool r = is_binary(tn) && constant_is_nonzero(tn->u.ops.right); 1607 1608 switch (tn->tn_op) { 1609 case NOT: 1610 if (hflag && !suppress_constcond) 1611 /* constant operand to '!' */ 1612 warning(239); 1613 v->u.integer = !l ? 1 : 0; 1614 break; 1615 case LOGAND: 1616 v->u.integer = l && r ? 1 : 0; 1617 break; 1618 case LOGOR: 1619 v->u.integer = l || r ? 1 : 0; 1620 break; 1621 default: 1622 lint_assert(/*CONSTCOND*/false); 1623 } 1624 1625 return build_constant(tn->tn_type, v); 1626 } 1627 1628 static long double 1629 floating_error_value(tspec_t t, long double lv) 1630 { 1631 if (t == FLOAT) 1632 return lv < 0 ? -FLT_MAX : FLT_MAX; 1633 if (t == DOUBLE) 1634 return lv < 0 ? -DBL_MAX : DBL_MAX; 1635 /* 1636 * When NetBSD is cross-built in MKLINT=yes mode on x86_64 for sparc64, 1637 * tools/lint checks this code while building usr.bin/xlint. In that 1638 * situation, lint uses the preprocessor for sparc64, in which the type 1639 * 'long double' is IEEE-754-binary128, affecting the macro LDBL_MAX 1640 * below. The type 'long double', as well as the strtold 1641 * implementation, comes from the host platform x86_64 though, where 1642 * 'long double' consumes 128 bits as well but only uses 80 of them. 1643 * The exponent range of the two 'long double' types is the same, but 1644 * the maximum finite value differs due to the extended precision on 1645 * sparc64. 1646 * 1647 * To properly handle the data types of the target platform, lint would 1648 * have to implement the floating-point types in a platform-independent 1649 * way, which is not worth the effort, given how few programs 1650 * practically use 'long double'. 1651 */ 1652 /* LINTED 248: floating-point constant out of range */ 1653 long double max = LDBL_MAX; 1654 return lv < 0 ? -max : max; 1655 } 1656 1657 static bool 1658 is_floating_overflow(tspec_t t, long double val) 1659 { 1660 if (fpe != 0 || isfinite(val) == 0) 1661 return true; 1662 if (t == FLOAT && (val > FLT_MAX || val < -FLT_MAX)) 1663 return true; 1664 if (t == DOUBLE && (val > DBL_MAX || val < -DBL_MAX)) 1665 return true; 1666 return false; 1667 } 1668 1669 static tnode_t * 1670 fold_constant_floating(tnode_t *tn) 1671 { 1672 1673 fpe = 0; 1674 1675 tspec_t t = tn->tn_type->t_tspec; 1676 1677 val_t *v = xcalloc(1, sizeof(*v)); 1678 v->v_tspec = t; 1679 1680 lint_assert(is_floating(t)); 1681 lint_assert(has_operands(tn)); 1682 lint_assert(t == tn->u.ops.left->tn_type->t_tspec); 1683 lint_assert(!is_binary(tn) || t == tn->u.ops.right->tn_type->t_tspec); 1684 1685 long double lv = tn->u.ops.left->u.value.u.floating; 1686 long double rv = is_binary(tn) ? tn->u.ops.right->u.value.u.floating 1687 : 0.0; 1688 1689 switch (tn->tn_op) { 1690 case UPLUS: 1691 v->u.floating = lv; 1692 break; 1693 case UMINUS: 1694 v->u.floating = -lv; 1695 break; 1696 case MULT: 1697 v->u.floating = lv * rv; 1698 break; 1699 case DIV: 1700 if (rv == 0.0) { 1701 /* division by 0 */ 1702 error(139); 1703 v->u.floating = floating_error_value(t, lv); 1704 } else { 1705 v->u.floating = lv / rv; 1706 } 1707 break; 1708 case PLUS: 1709 v->u.floating = lv + rv; 1710 break; 1711 case MINUS: 1712 v->u.floating = lv - rv; 1713 break; 1714 case LT: 1715 v->u.integer = lv < rv ? 1 : 0; 1716 break; 1717 case LE: 1718 v->u.integer = lv <= rv ? 1 : 0; 1719 break; 1720 case GE: 1721 v->u.integer = lv >= rv ? 1 : 0; 1722 break; 1723 case GT: 1724 v->u.integer = lv > rv ? 1 : 0; 1725 break; 1726 case EQ: 1727 v->u.integer = lv == rv ? 1 : 0; 1728 break; 1729 case NE: 1730 v->u.integer = lv != rv ? 1 : 0; 1731 break; 1732 default: 1733 lint_assert(/*CONSTCOND*/false); 1734 } 1735 1736 // XXX: Must not access u.floating after setting u.integer. 1737 lint_assert(fpe != 0 || isnan(v->u.floating) == 0); 1738 if (is_complex(v->v_tspec)) { 1739 /* 1740 * Don't warn, as lint doesn't model the imaginary part of 1741 * complex numbers. 1742 */ 1743 fpe = 0; 1744 } else if (is_floating_overflow(t, v->u.floating)) { 1745 /* operator '%s' produces floating point overflow */ 1746 warning(142, op_name(tn->tn_op)); 1747 v->u.floating = floating_error_value(t, v->u.floating); 1748 fpe = 0; 1749 } 1750 1751 return build_constant(tn->tn_type, v); 1752 } 1753 1754 static void 1755 use(const tnode_t *tn) 1756 { 1757 if (tn == NULL) 1758 return; 1759 switch (tn->tn_op) { 1760 case NAME: 1761 mark_as_used(tn->u.sym, false /* XXX */, false /* XXX */); 1762 break; 1763 case CON: 1764 case STRING: 1765 break; 1766 case CALL:; 1767 const function_call *call = tn->u.call; 1768 for (size_t i = 0, n = call->args_len; i < n; i++) 1769 use(call->args[i]); 1770 break; 1771 default: 1772 lint_assert(has_operands(tn)); 1773 use(tn->u.ops.left); 1774 if (is_binary(tn)) 1775 use(tn->u.ops.right); 1776 } 1777 } 1778 1779 /* 1780 * Create a tree node for a binary operator and its two operands. Also called 1781 * for unary operators; in that case rn is NULL. 1782 * 1783 * Function calls, sizeof and casts are handled elsewhere. 1784 */ 1785 tnode_t * 1786 build_binary(tnode_t *ln, op_t op, bool sys, tnode_t *rn) 1787 { 1788 const mod_t *mp = &modtab[op]; 1789 1790 /* If there was an error in one of the operands, return. */ 1791 if (ln == NULL || (mp->m_binary && rn == NULL)) 1792 return NULL; 1793 1794 if (mp->m_value_context || mp->m_compares_with_zero) 1795 ln = cconv(ln); 1796 if (mp->m_binary && op != ARROW && op != POINT) 1797 rn = cconv(rn); 1798 1799 if (mp->m_comparison) 1800 check_integer_comparison(op, ln, rn); 1801 1802 if (mp->m_value_context || mp->m_compares_with_zero) 1803 ln = promote(op, false, ln); 1804 if (mp->m_binary && op != ARROW && op != POINT && 1805 op != ASSIGN && op != RETURN && op != INIT) 1806 rn = promote(op, false, rn); 1807 1808 if (mp->m_warn_if_left_unsigned_in_c90 && 1809 ln->tn_op == CON && ln->u.value.v_unsigned_since_c90) { 1810 /* C90 treats constant as unsigned, op '%s' */ 1811 warning(218, op_name(op)); 1812 ln->u.value.v_unsigned_since_c90 = false; 1813 } 1814 if (mp->m_warn_if_right_unsigned_in_c90 && 1815 rn->tn_op == CON && rn->u.value.v_unsigned_since_c90) { 1816 /* C90 treats constant as unsigned, op '%s' */ 1817 warning(218, op_name(op)); 1818 rn->u.value.v_unsigned_since_c90 = false; 1819 } 1820 1821 if (mp->m_balance_operands || (!allow_c90 && (op == SHL || op == SHR))) 1822 balance(op, &ln, &rn); 1823 1824 if (!typeok(op, 0, ln, rn)) 1825 return NULL; 1826 1827 tnode_t *ntn; 1828 switch (op) { 1829 case POINT: 1830 case ARROW: 1831 ntn = build_struct_access(op, sys, ln, rn); 1832 break; 1833 case NOT: 1834 if (ln->tn_op == ASSIGN && ln->u.ops.right->tn_op == CON) { 1835 /* constant assignment of type '%s' in operand ... */ 1836 warning(382, type_name(ln->tn_type), 1837 is_nonzero_val(&ln->u.ops.right->u.value) 1838 ? "true" : "false"); 1839 } 1840 ntn = build_op(op, sys, gettyp(Tflag ? BOOL : INT), ln, NULL); 1841 break; 1842 case INCAFT: 1843 case DECAFT: 1844 case INCBEF: 1845 case DECBEF: 1846 ntn = build_prepost_incdec(op, sys, ln); 1847 break; 1848 case ADDR: 1849 ntn = build_address(sys, ln, false); 1850 break; 1851 case INDIR: 1852 ntn = build_op(INDIR, sys, ln->tn_type->t_subt, ln, NULL); 1853 break; 1854 case PLUS: 1855 case MINUS: 1856 ntn = build_plus_minus(op, sys, ln, rn); 1857 break; 1858 case SHL: 1859 case SHR: 1860 ntn = build_bit_shift(op, sys, ln, rn); 1861 break; 1862 case COLON: 1863 ntn = build_colon(sys, ln, rn); 1864 break; 1865 case ASSIGN: 1866 case MULASS: 1867 case DIVASS: 1868 case MODASS: 1869 case ADDASS: 1870 case SUBASS: 1871 case SHLASS: 1872 case SHRASS: 1873 case ANDASS: 1874 case XORASS: 1875 case ORASS: 1876 case RETURN: 1877 case INIT: 1878 ntn = build_assignment(op, sys, ln, rn); 1879 break; 1880 case COMMA: 1881 if (any_query_enabled) { 1882 /* comma operator with types '%s' and '%s' */ 1883 query_message(12, 1884 type_name(ln->tn_type), type_name(rn->tn_type)); 1885 } 1886 /* FALLTHROUGH */ 1887 case QUEST: 1888 ntn = build_op(op, sys, rn->tn_type, ln, rn); 1889 break; 1890 case REAL: 1891 case IMAG: 1892 ntn = build_real_imag(op, sys, ln); 1893 break; 1894 default: 1895 lint_assert(mp->m_binary == (rn != NULL)); 1896 type_t *rettp = mp->m_returns_bool 1897 ? gettyp(Tflag ? BOOL : INT) : ln->tn_type; 1898 ntn = build_op(op, sys, rettp, ln, rn); 1899 break; 1900 } 1901 1902 if (ntn == NULL) 1903 return NULL; 1904 1905 if (mp->m_possible_precedence_confusion) 1906 check_precedence_confusion(ntn); 1907 1908 if (hflag && !suppress_constcond && 1909 mp->m_compares_with_zero && 1910 (ln->tn_op == CON || 1911 (mp->m_binary && op != QUEST && rn->tn_op == CON)) && 1912 /* XXX: rn->tn_system_dependent should be checked as well */ 1913 !ln->tn_system_dependent) 1914 /* constant in conditional context */ 1915 warning(161); 1916 1917 if (mp->m_fold_constant_operands && ln->tn_op == CON) { 1918 if (!mp->m_binary || rn->tn_op == CON) { 1919 if (mp->m_compares_with_zero) 1920 ntn = fold_constant_compare_zero(ntn); 1921 else if (is_floating(ntn->tn_type->t_tspec)) 1922 ntn = fold_constant_floating(ntn); 1923 else 1924 ntn = fold_constant_integer(ntn); 1925 } else if (op == QUEST) { 1926 lint_assert(has_operands(rn)); 1927 use(ln->u.value.u.integer != 0 1928 ? rn->u.ops.right : rn->u.ops.left); 1929 ntn = ln->u.value.u.integer != 0 1930 ? rn->u.ops.left : rn->u.ops.right; 1931 } 1932 } 1933 1934 return ntn; 1935 } 1936 1937 tnode_t * 1938 build_unary(op_t op, bool sys, tnode_t *tn) 1939 { 1940 return build_binary(tn, op, sys, NULL); 1941 } 1942 1943 static bool 1944 are_members_compatible(const sym_t *a, const sym_t *b) 1945 { 1946 if (a->u.s_member.sm_offset_in_bits != b->u.s_member.sm_offset_in_bits) 1947 return false; 1948 1949 const type_t *atp = a->s_type; 1950 const type_t *btp = b->s_type; 1951 bool w = false; 1952 if (!types_compatible(atp, btp, false, false, &w) && !w) 1953 return false; 1954 if (a->s_bitfield != b->s_bitfield) 1955 return false; 1956 if (a->s_bitfield) { 1957 if (atp->t_bit_field_width != btp->t_bit_field_width) 1958 return false; 1959 if (atp->t_bit_field_offset != btp->t_bit_field_offset) 1960 return false; 1961 } 1962 return true; 1963 } 1964 1965 /* 1966 * Return whether all struct/union members with the same name have the same 1967 * type and offset. 1968 */ 1969 static bool 1970 all_members_compatible(const sym_t *msym) 1971 { 1972 for (const sym_t *csym = msym; 1973 csym != NULL; csym = csym->s_symtab_next) { 1974 if (!is_member(csym)) 1975 continue; 1976 if (strcmp(msym->s_name, csym->s_name) != 0) 1977 continue; 1978 1979 for (const sym_t *sym = csym->s_symtab_next; 1980 sym != NULL; sym = sym->s_symtab_next) { 1981 if (is_member(sym) 1982 && strcmp(csym->s_name, sym->s_name) == 0 1983 && !are_members_compatible(csym, sym)) 1984 return false; 1985 } 1986 } 1987 return true; 1988 } 1989 1990 sym_t * 1991 find_member(const struct_or_union *sou, const char *name) 1992 { 1993 for (sym_t *mem = sou->sou_first_member; 1994 mem != NULL; mem = mem->s_next) { 1995 lint_assert(is_member(mem)); 1996 lint_assert(mem->u.s_member.sm_containing_type == sou); 1997 if (strcmp(mem->s_name, name) == 0) 1998 return mem; 1999 } 2000 2001 for (sym_t *mem = sou->sou_first_member; 2002 mem != NULL; mem = mem->s_next) { 2003 if (is_struct_or_union(mem->s_type->t_tspec) 2004 && mem->s_name == unnamed) { 2005 sym_t *nested_mem = 2006 find_member(mem->s_type->u.sou, name); 2007 if (nested_mem != NULL) 2008 return nested_mem; 2009 } 2010 } 2011 return NULL; 2012 } 2013 2014 /* 2015 * Remove the member if it was unknown until now, which means 2016 * that no defined struct or union has a member with the same name. 2017 */ 2018 static void 2019 remove_unknown_member(tnode_t *tn, sym_t *msym) 2020 { 2021 /* type '%s' does not have member '%s' */ 2022 error(101, type_name(tn->tn_type), msym->s_name); 2023 symtab_remove_forever(msym); 2024 msym->s_kind = SK_MEMBER; 2025 msym->s_scl = STRUCT_MEMBER; 2026 2027 struct_or_union *sou = expr_zero_alloc(sizeof(*sou), 2028 "struct_or_union"); 2029 sou->sou_tag = expr_zero_alloc(sizeof(*sou->sou_tag), "sym"); 2030 sou->sou_tag->s_name = unnamed; 2031 2032 msym->u.s_member.sm_containing_type = sou; 2033 /* 2034 * The member sm_offset_in_bits is not needed here since this symbol 2035 * can only be used for error reporting. 2036 */ 2037 } 2038 2039 /* 2040 * Returns a symbol which has the same name as 'msym' and is a member of the 2041 * struct or union specified by 'tn'. 2042 */ 2043 static sym_t * 2044 struct_or_union_member(tnode_t *tn, op_t op, sym_t *msym) 2045 { 2046 2047 /* Determine the tag type of which msym is expected to be a member. */ 2048 const type_t *tp = NULL; 2049 if (op == POINT && is_struct_or_union(tn->tn_type->t_tspec)) 2050 tp = tn->tn_type; 2051 if (op == ARROW && tn->tn_type->t_tspec == PTR 2052 && is_struct_or_union(tn->tn_type->t_subt->t_tspec)) 2053 tp = tn->tn_type->t_subt; 2054 struct_or_union *sou = tp != NULL ? tp->u.sou : NULL; 2055 2056 if (sou != NULL) { 2057 sym_t *nested_mem = find_member(sou, msym->s_name); 2058 if (nested_mem != NULL) 2059 return nested_mem; 2060 } 2061 2062 if (msym->s_scl == NO_SCL) { 2063 remove_unknown_member(tn, msym); 2064 return msym; 2065 } 2066 2067 bool eq = all_members_compatible(msym); 2068 2069 /* 2070 * Now handle the case in which the left operand refers really to a 2071 * struct/union, but the right operand is not member of it. 2072 */ 2073 if (sou != NULL) { 2074 if (eq && !allow_c90) 2075 /* illegal use of member '%s' */ 2076 warning(102, msym->s_name); 2077 else 2078 /* illegal use of member '%s' */ 2079 error(102, msym->s_name); 2080 return msym; 2081 } 2082 2083 if (eq) { 2084 if (op == POINT) { 2085 if (!allow_c90) 2086 /* left operand of '.' must be struct ... */ 2087 warning(103, type_name(tn->tn_type)); 2088 else 2089 /* left operand of '.' must be struct ... */ 2090 error(103, type_name(tn->tn_type)); 2091 } else { 2092 if (!allow_c90 && tn->tn_type->t_tspec == PTR) 2093 /* left operand of '->' must be pointer ... */ 2094 warning(104, type_name(tn->tn_type)); 2095 else 2096 /* left operand of '->' must be pointer ... */ 2097 error(104, type_name(tn->tn_type)); 2098 } 2099 } else { 2100 if (!allow_c90) 2101 /* non-unique member requires struct/union %s */ 2102 error(105, op == POINT ? "object" : "pointer"); 2103 else 2104 /* unacceptable operand of '%s' */ 2105 error(111, op_name(op)); 2106 } 2107 2108 return msym; 2109 } 2110 2111 tnode_t * 2112 build_member_access(tnode_t *ln, op_t op, bool sys, sbuf_t *member) 2113 { 2114 sym_t *msym; 2115 2116 if (ln == NULL) 2117 return NULL; 2118 2119 if (op == ARROW) 2120 /* must do this before struct_or_union_member is called */ 2121 ln = cconv(ln); 2122 msym = struct_or_union_member(ln, op, getsym(member)); 2123 return build_binary(ln, op, sys, build_name(msym, false)); 2124 } 2125 2126 /* 2127 * Perform class conversions. 2128 * 2129 * Arrays of type T are converted into pointers to type T. 2130 * Functions are converted to pointers to functions. 2131 * Lvalues are converted to rvalues. 2132 * 2133 * C99 6.3 "Conversions" 2134 * C99 6.3.2 "Other operands" 2135 * C99 6.3.2.1 "Lvalues, arrays, and function designators" 2136 */ 2137 tnode_t * 2138 cconv(tnode_t *tn) 2139 { 2140 if (tn->tn_type->t_tspec == ARRAY) { 2141 if (!tn->tn_lvalue) { 2142 /* XXX print correct operator */ 2143 /* %soperand of '%s' must be lvalue */ 2144 gnuism(114, "", op_name(ADDR)); 2145 } 2146 tn = build_op(ADDR, tn->tn_sys, 2147 expr_derive_type(tn->tn_type->t_subt, PTR), tn, NULL); 2148 } 2149 2150 if (tn->tn_type->t_tspec == FUNC) 2151 tn = build_address(tn->tn_sys, tn, true); 2152 2153 if (tn->tn_lvalue) { 2154 type_t *tp = expr_dup_type(tn->tn_type); 2155 /* C99 6.3.2.1p2 sentence 2 says to remove the qualifiers. */ 2156 tp->t_const = tp->t_volatile = false; 2157 tn = build_op(LOAD, tn->tn_sys, tp, tn, NULL); 2158 } 2159 2160 return tn; 2161 } 2162 2163 const tnode_t * 2164 before_conversion(const tnode_t *tn) 2165 { 2166 while (tn->tn_op == CVT && !tn->tn_cast) 2167 tn = tn->u.ops.left; 2168 return tn; 2169 } 2170 2171 /* 2172 * Most errors required by C90 are reported in struct_or_union_member(). 2173 * Here we only check for totally wrong things. 2174 */ 2175 static bool 2176 typeok_point(const tnode_t *ln, const type_t *ltp, tspec_t lt) 2177 { 2178 if (is_struct_or_union(lt)) 2179 return true; 2180 2181 if (lt == FUNC || lt == VOID || ltp->t_bitfield) 2182 goto wrong; 2183 2184 /* 2185 * Some C dialects from before C90 tolerated any lvalue on the 2186 * left-hand side of the '.' operator, allowing things like 'char 2187 * st[100]; st.st_mtime', assuming that the member 'st_mtime' only 2188 * occurred in a single struct; see typeok_arrow. 2189 */ 2190 if (ln->tn_lvalue) 2191 return true; 2192 2193 wrong: 2194 /* With allow_c90 we already got an error */ 2195 if (!allow_c90) 2196 /* unacceptable operand of '%s' */ 2197 error(111, op_name(POINT)); 2198 2199 return false; 2200 } 2201 2202 static bool 2203 typeok_arrow(tspec_t lt) 2204 { 2205 /* 2206 * C1978 Appendix A 14.1 says: <quote>In fact, any lvalue is allowed 2207 * before '.', and that lvalue is then assumed to have the form of the 2208 * structure of which the name of the right is a member. [...] Such 2209 * constructions are non-portable.</quote> 2210 */ 2211 if (lt == PTR || (!allow_c90 && is_integer(lt))) 2212 return true; 2213 2214 /* With allow_c90 we already got an error */ 2215 if (!allow_c90) 2216 /* unacceptable operand of '%s' */ 2217 error(111, op_name(ARROW)); 2218 return false; 2219 } 2220 2221 static bool 2222 typeok_incdec(op_t op, const tnode_t *tn, const type_t *tp) 2223 { 2224 /* operand has scalar type (checked in typeok) */ 2225 if (!tn->tn_lvalue) { 2226 if (tn->tn_op == CVT && tn->tn_cast && 2227 tn->u.ops.left->tn_op == LOAD) 2228 /* a cast does not yield an lvalue */ 2229 error(163); 2230 /* %soperand of '%s' must be lvalue */ 2231 error(114, "", op_name(op)); 2232 return false; 2233 } 2234 if (tp->t_const && allow_c90) 2235 /* %soperand of '%s' must be modifiable lvalue */ 2236 warning(115, "", op_name(op)); 2237 return true; 2238 } 2239 2240 static bool 2241 typeok_address(op_t op, const tnode_t *tn, const type_t *tp, tspec_t t) 2242 { 2243 if (t == ARRAY || t == FUNC) { 2244 /* ok, a warning comes later (in build_address()) */ 2245 } else if (!tn->tn_lvalue) { 2246 if (tn->tn_op == CVT && tn->tn_cast && 2247 tn->u.ops.left->tn_op == LOAD) 2248 /* a cast does not yield an lvalue */ 2249 error(163); 2250 /* %soperand of '%s' must be lvalue */ 2251 error(114, "", op_name(op)); 2252 return false; 2253 } else if (is_scalar(t)) { 2254 if (tp->t_bitfield) { 2255 /* cannot take address of bit-field */ 2256 error(112); 2257 return false; 2258 } 2259 } else if (t != STRUCT && t != UNION) { 2260 /* unacceptable operand of '%s' */ 2261 error(111, op_name(op)); 2262 return false; 2263 } 2264 if (tn->tn_op == NAME && tn->u.sym->s_register) { 2265 /* cannot take address of register '%s' */ 2266 error(113, tn->u.sym->s_name); 2267 return false; 2268 } 2269 return true; 2270 } 2271 2272 static bool 2273 typeok_indir(const type_t *tp, tspec_t t) 2274 { 2275 2276 if (t != PTR) { 2277 /* cannot dereference non-pointer type '%s' */ 2278 error(96, type_name(tp)); 2279 return false; 2280 } 2281 return true; 2282 } 2283 2284 static void 2285 warn_incompatible_types(op_t op, 2286 const type_t *ltp, tspec_t lt, 2287 const type_t *rtp, tspec_t rt) 2288 { 2289 bool binary = modtab[op].m_binary; 2290 2291 if (lt == VOID || (binary && rt == VOID)) { 2292 /* void type illegal in expression */ 2293 error(109); 2294 } else if (op == ASSIGN) 2295 /* cannot assign to '%s' from '%s' */ 2296 error(171, type_name(ltp), type_name(rtp)); 2297 else if (binary) 2298 /* operands of '%s' have incompatible types '%s' and '%s' */ 2299 error(107, op_name(op), type_name(ltp), type_name(rtp)); 2300 else { 2301 lint_assert(rt == NO_TSPEC); 2302 /* operand of '%s' has invalid type '%s' */ 2303 error(108, op_name(op), type_name(ltp)); 2304 } 2305 } 2306 2307 static bool 2308 typeok_plus(op_t op, 2309 const type_t *ltp, tspec_t lt, 2310 const type_t *rtp, tspec_t rt) 2311 { 2312 /* operands have scalar types (checked in typeok) */ 2313 if ((lt == PTR && !is_integer(rt)) || (rt == PTR && !is_integer(lt))) { 2314 warn_incompatible_types(op, ltp, lt, rtp, rt); 2315 return false; 2316 } 2317 return true; 2318 } 2319 2320 static bool 2321 typeok_minus(op_t op, 2322 const type_t *ltp, tspec_t lt, 2323 const type_t *rtp, tspec_t rt) 2324 { 2325 /* operands have scalar types (checked in typeok) */ 2326 if ((lt == PTR && rt != PTR && !is_integer(rt)) || 2327 (lt != PTR && rt == PTR)) { 2328 warn_incompatible_types(op, ltp, lt, rtp, rt); 2329 return false; 2330 } 2331 if (lt == PTR && rt == PTR && 2332 !types_compatible(ltp->t_subt, rtp->t_subt, true, false, NULL)) { 2333 /* illegal pointer subtraction */ 2334 error(116); 2335 } 2336 return true; 2337 } 2338 2339 static void 2340 typeok_shr(op_t op, 2341 const tnode_t *ln, tspec_t lt, 2342 const tnode_t *rn, tspec_t rt) 2343 { 2344 tspec_t olt = before_conversion(ln)->tn_type->t_tspec; 2345 tspec_t ort = before_conversion(rn)->tn_type->t_tspec; 2346 2347 /* operands have integer types (checked in typeok) */ 2348 if (pflag && !is_uinteger(olt)) { 2349 integer_constraints lc = ic_expr(ln); 2350 if (!ic_maybe_signed(ln->tn_type, &lc)) 2351 return; 2352 2353 if (ln->tn_op != CON) 2354 /* bitwise '%s' on signed value possibly nonportable */ 2355 warning(117, op_name(op)); 2356 else if (ln->u.value.u.integer < 0) 2357 /* bitwise '%s' on signed value nonportable */ 2358 warning(120, op_name(op)); 2359 } else if (allow_trad && allow_c90 && 2360 !is_uinteger(olt) && is_uinteger(ort)) { 2361 /* The left operand would become unsigned in traditional C. */ 2362 if (hflag && (ln->tn_op != CON || ln->u.value.u.integer < 0)) { 2363 /* semantics of '%s' change in C90; use ... */ 2364 warning(118, op_name(op)); 2365 } 2366 } else if (allow_trad && allow_c90 && 2367 !is_uinteger(olt) && !is_uinteger(ort) && 2368 portable_rank_cmp(lt, rt) < 0) { 2369 /* 2370 * In traditional C, the left operand would be extended 2371 * (possibly sign-extended) and then shifted. 2372 */ 2373 if (hflag && (ln->tn_op != CON || ln->u.value.u.integer < 0)) { 2374 /* semantics of '%s' change in C90; use ... */ 2375 warning(118, op_name(op)); 2376 } 2377 } 2378 } 2379 2380 static void 2381 typeok_shl(op_t op, tspec_t lt, tspec_t rt) 2382 { 2383 /* 2384 * C90 does not perform balancing for shift operations, but traditional 2385 * C does. If the width of the right operand is greater than the width 2386 * of the left operand, then in traditional C the left operand would be 2387 * extended to the width of the right operand. For SHL this may result 2388 * in different results. 2389 */ 2390 if (portable_rank_cmp(lt, rt) < 0) { 2391 /* 2392 * XXX If both operands are constant, make sure that there is 2393 * really a difference between C90 and traditional C. 2394 */ 2395 if (hflag && allow_trad && allow_c90) 2396 /* semantics of '%s' change in C90; use ... */ 2397 warning(118, op_name(op)); 2398 } 2399 } 2400 2401 static void 2402 typeok_shift(const type_t *ltp, tspec_t lt, const tnode_t *rn, tspec_t rt) 2403 { 2404 if (rn->tn_op != CON) 2405 return; 2406 2407 if (!is_uinteger(rt) && rn->u.value.u.integer < 0) 2408 /* negative shift */ 2409 warning(121); 2410 else if ((uint64_t)rn->u.value.u.integer == size_in_bits(lt)) 2411 /* shift amount %u equals bit-size of '%s' */ 2412 warning(267, (unsigned)rn->u.value.u.integer, type_name(ltp)); 2413 else if ((uint64_t)rn->u.value.u.integer > size_in_bits(lt)) { 2414 /* shift amount %llu is greater than bit-size %llu of '%s' */ 2415 warning(122, (unsigned long long)rn->u.value.u.integer, 2416 (unsigned long long)size_in_bits(lt), 2417 tspec_name(lt)); 2418 } 2419 } 2420 2421 static bool 2422 is_typeok_eq(const tnode_t *ln, tspec_t lt, const tnode_t *rn, tspec_t rt) 2423 { 2424 if (lt == PTR && is_null_pointer(rn)) 2425 return true; 2426 if (rt == PTR && is_null_pointer(ln)) 2427 return true; 2428 return false; 2429 } 2430 2431 static void 2432 warn_incompatible_pointers(op_t op, const type_t *ltp, const type_t *rtp) 2433 { 2434 lint_assert(ltp->t_tspec == PTR); 2435 lint_assert(rtp->t_tspec == PTR); 2436 2437 tspec_t lt = ltp->t_subt->t_tspec; 2438 tspec_t rt = rtp->t_subt->t_tspec; 2439 2440 if (is_struct_or_union(lt) && is_struct_or_union(rt)) { 2441 if (op == RETURN) 2442 /* illegal structure pointer combination */ 2443 warning(244); 2444 else { 2445 /* incompatible structure pointers: '%s' '%s' '%s' */ 2446 warning(245, type_name(ltp), 2447 op_name(op), type_name(rtp)); 2448 } 2449 } else { 2450 if (op == RETURN) 2451 /* illegal combination of '%s' and '%s' */ 2452 warning(184, type_name(ltp), type_name(rtp)); 2453 else { 2454 /* illegal combination of '%s' and '%s', op '%s' */ 2455 warning(124, 2456 type_name(ltp), type_name(rtp), op_name(op)); 2457 } 2458 } 2459 } 2460 2461 static void 2462 check_pointer_comparison(op_t op, const tnode_t *ln, const tnode_t *rn) 2463 { 2464 type_t *ltp = ln->tn_type, *rtp = rn->tn_type; 2465 tspec_t lst = ltp->t_subt->t_tspec, rst = rtp->t_subt->t_tspec; 2466 2467 if (lst == VOID || rst == VOID) { 2468 /* TODO: C99 behaves like C90 here. */ 2469 if (!allow_trad && !allow_c99 && 2470 (lst == FUNC || rst == FUNC)) { 2471 /* (void *)0 is already handled in typeok() */ 2472 const char *lsts, *rsts; 2473 *(lst == FUNC ? &lsts : &rsts) = "function pointer"; 2474 *(lst == VOID ? &lsts : &rsts) = "'void *'"; 2475 /* C90 or later forbid comparison of %s with %s */ 2476 warning(274, lsts, rsts); 2477 } 2478 return; 2479 } 2480 2481 if (!types_compatible(ltp->t_subt, rtp->t_subt, true, false, NULL)) { 2482 warn_incompatible_pointers(op, ltp, rtp); 2483 return; 2484 } 2485 2486 if (lst == FUNC && rst == FUNC) { 2487 /* TODO: C99 behaves like C90 here, see C99 6.5.8p2. */ 2488 if (!allow_trad && !allow_c99 && op != EQ && op != NE) 2489 /* pointers to functions can only be compared ... */ 2490 warning(125); 2491 } 2492 } 2493 2494 static bool 2495 typeok_compare(op_t op, 2496 const tnode_t *ln, const type_t *ltp, tspec_t lt, 2497 const tnode_t *rn, const type_t *rtp, tspec_t rt) 2498 { 2499 if (lt == PTR && rt == PTR) { 2500 check_pointer_comparison(op, ln, rn); 2501 return true; 2502 } 2503 2504 if (lt != PTR && rt != PTR) 2505 return true; 2506 2507 if (!is_integer(lt) && !is_integer(rt)) { 2508 warn_incompatible_types(op, ltp, lt, rtp, rt); 2509 return false; 2510 } 2511 2512 const char *lx = lt == PTR ? "pointer" : "integer"; 2513 const char *rx = rt == PTR ? "pointer" : "integer"; 2514 /* illegal combination of %s '%s' and %s '%s', op '%s' */ 2515 warning(123, lx, type_name(ltp), rx, type_name(rtp), op_name(op)); 2516 return true; 2517 } 2518 2519 static bool 2520 typeok_quest(tspec_t lt, const tnode_t *rn) 2521 { 2522 if (!is_scalar(lt)) { 2523 /* first operand of '?' must have scalar type */ 2524 error(170); 2525 return false; 2526 } 2527 lint_assert(before_conversion(rn)->tn_op == COLON); 2528 return true; 2529 } 2530 2531 static void 2532 typeok_colon_pointer(const type_t *ltp, const type_t *rtp) 2533 { 2534 type_t *lstp = ltp->t_subt; 2535 type_t *rstp = rtp->t_subt; 2536 tspec_t lst = lstp->t_tspec; 2537 tspec_t rst = rstp->t_tspec; 2538 2539 if ((lst == VOID && rst == FUNC) || (lst == FUNC && rst == VOID)) { 2540 /* (void *)0 is handled in typeok_colon */ 2541 /* TODO: C99 behaves like C90 here. */ 2542 if (!allow_trad && !allow_c99) 2543 /* conversion of %s to %s requires a cast, op %s */ 2544 warning(305, "function pointer", "'void *'", 2545 op_name(COLON)); 2546 return; 2547 } 2548 2549 if (pointer_types_are_compatible(lstp, rstp, true)) 2550 return; 2551 if (!types_compatible(lstp, rstp, true, false, NULL)) 2552 warn_incompatible_pointers(COLON, ltp, rtp); 2553 } 2554 2555 static bool 2556 typeok_colon(const tnode_t *ln, const type_t *ltp, tspec_t lt, 2557 const tnode_t *rn, const type_t *rtp, tspec_t rt) 2558 { 2559 2560 if (is_arithmetic(lt) && is_arithmetic(rt)) 2561 return true; 2562 if (lt == BOOL && rt == BOOL) 2563 return true; 2564 2565 if (lt == STRUCT && rt == STRUCT && ltp->u.sou == rtp->u.sou) 2566 return true; 2567 if (lt == UNION && rt == UNION && ltp->u.sou == rtp->u.sou) 2568 return true; 2569 2570 if (lt == PTR && is_null_pointer(rn)) 2571 return true; 2572 if (rt == PTR && is_null_pointer(ln)) 2573 return true; 2574 2575 if ((lt == PTR && is_integer(rt)) || (is_integer(lt) && rt == PTR)) { 2576 const char *lx = lt == PTR ? "pointer" : "integer"; 2577 const char *rx = rt == PTR ? "pointer" : "integer"; 2578 /* illegal combination of %s '%s' and %s '%s', op '%s' */ 2579 warning(123, lx, type_name(ltp), 2580 rx, type_name(rtp), op_name(COLON)); 2581 return true; 2582 } 2583 2584 if (lt == VOID || rt == VOID) { 2585 if (lt != VOID || rt != VOID) 2586 /* incompatible types '%s' and '%s' in conditional */ 2587 warning(126, type_name(ltp), type_name(rtp)); 2588 return true; 2589 } 2590 2591 if (lt == PTR && rt == PTR) { 2592 typeok_colon_pointer(ltp, rtp); 2593 return true; 2594 } 2595 2596 /* incompatible types '%s' and '%s' in conditional */ 2597 error(126, type_name(ltp), type_name(rtp)); 2598 return false; 2599 } 2600 2601 static bool 2602 has_constant_member(const type_t *tp) 2603 { 2604 lint_assert(is_struct_or_union(tp->t_tspec)); 2605 2606 for (sym_t *m = tp->u.sou->sou_first_member; 2607 m != NULL; m = m->s_next) { 2608 const type_t *mtp = m->s_type; 2609 if (mtp->t_const) 2610 return true; 2611 if (is_struct_or_union(mtp->t_tspec) && 2612 has_constant_member(mtp)) 2613 return true; 2614 } 2615 return false; 2616 } 2617 2618 static bool 2619 typeok_assign(op_t op, const tnode_t *ln, const type_t *ltp, tspec_t lt) 2620 { 2621 if (op == RETURN || op == INIT || op == FARG) 2622 return true; 2623 2624 if (!ln->tn_lvalue) { 2625 if (ln->tn_op == CVT && ln->tn_cast && 2626 ln->u.ops.left->tn_op == LOAD) 2627 /* a cast does not yield an lvalue */ 2628 error(163); 2629 /* %soperand of '%s' must be lvalue */ 2630 error(114, "left ", op_name(op)); 2631 return false; 2632 } else if (ltp->t_const 2633 || (is_struct_or_union(lt) && has_constant_member(ltp))) { 2634 if (allow_c90) 2635 /* %soperand of '%s' must be modifiable lvalue */ 2636 warning(115, "left ", op_name(op)); 2637 } 2638 return true; 2639 } 2640 2641 static bool 2642 typeok_scalar(op_t op, const mod_t *mp, 2643 const type_t *ltp, tspec_t lt, 2644 const type_t *rtp, tspec_t rt) 2645 { 2646 if (mp->m_takes_bool && lt == BOOL && rt == BOOL) 2647 return true; 2648 if (mp->m_requires_integer) { 2649 if (!is_integer(lt) || (mp->m_binary && !is_integer(rt))) { 2650 warn_incompatible_types(op, ltp, lt, rtp, rt); 2651 return false; 2652 } 2653 } else if (mp->m_requires_integer_or_complex) { 2654 if ((!is_integer(lt) && !is_complex(lt)) || 2655 (mp->m_binary && (!is_integer(rt) && !is_complex(rt)))) { 2656 warn_incompatible_types(op, ltp, lt, rtp, rt); 2657 return false; 2658 } 2659 } else if (mp->m_requires_scalar) { 2660 if (!is_scalar(lt) || (mp->m_binary && !is_scalar(rt))) { 2661 warn_incompatible_types(op, ltp, lt, rtp, rt); 2662 return false; 2663 } 2664 } else if (mp->m_requires_arith) { 2665 if (!is_arithmetic(lt) || 2666 (mp->m_binary && !is_arithmetic(rt))) { 2667 warn_incompatible_types(op, ltp, lt, rtp, rt); 2668 return false; 2669 } 2670 } 2671 return true; 2672 } 2673 2674 static void 2675 check_assign_void_pointer(op_t op, int arg, 2676 tspec_t lt, tspec_t lst, 2677 tspec_t rt, tspec_t rst) 2678 { 2679 2680 if (!(lt == PTR && rt == PTR && (lst == VOID || rst == VOID))) 2681 return; 2682 /* two pointers, at least one pointer to void */ 2683 2684 /* TODO: C99 behaves like C90 here. */ 2685 if (!(!allow_trad && !allow_c99 && (lst == FUNC || rst == FUNC))) 2686 return; 2687 /* comb. of ptr to func and ptr to void */ 2688 2689 const char *lts, *rts; 2690 *(lst == FUNC ? <s : &rts) = "function pointer"; 2691 *(lst == VOID ? <s : &rts) = "'void *'"; 2692 2693 switch (op) { 2694 case INIT: 2695 case RETURN: 2696 /* conversion of %s to %s requires a cast */ 2697 warning(303, rts, lts); 2698 break; 2699 case FARG: 2700 /* conversion of %s to %s requires a cast, arg #%d */ 2701 warning(304, rts, lts, arg); 2702 break; 2703 default: 2704 /* conversion of %s to %s requires a cast, op %s */ 2705 warning(305, rts, lts, op_name(op)); 2706 break; 2707 } 2708 } 2709 2710 static bool 2711 is_direct_function_call(const tnode_t *tn, const char **out_name) 2712 { 2713 2714 if (tn->tn_op == CALL 2715 && tn->u.call->func->tn_op == ADDR 2716 && tn->u.call->func->u.ops.left->tn_op == NAME) { 2717 *out_name = tn->u.call->func->u.ops.left->u.sym->s_name; 2718 return true; 2719 } 2720 return false; 2721 } 2722 2723 static bool 2724 is_unconst_function(const char *name) 2725 { 2726 2727 return strcmp(name, "memchr") == 0 || 2728 strcmp(name, "strchr") == 0 || 2729 strcmp(name, "strpbrk") == 0 || 2730 strcmp(name, "strrchr") == 0 || 2731 strcmp(name, "strstr") == 0; 2732 } 2733 2734 static bool 2735 is_const_char_pointer(const tnode_t *tn) 2736 { 2737 /* 2738 * For traditional reasons, C99 6.4.5p5 defines that string literals 2739 * have type 'char[]'. They are often implicitly converted to 'char 2740 * *', for example when they are passed as function arguments. 2741 * 2742 * C99 6.4.5p6 further defines that modifying a string that is 2743 * constructed from a string literal invokes undefined behavior. 2744 * 2745 * Out of these reasons, string literals are treated as 'effectively 2746 * const' here. 2747 */ 2748 if (tn->tn_op == CVT && 2749 tn->u.ops.left->tn_op == ADDR && 2750 tn->u.ops.left->u.ops.left->tn_op == STRING) 2751 return true; 2752 2753 const type_t *tp = before_conversion(tn)->tn_type; 2754 return tp->t_tspec == PTR && 2755 tp->t_subt->t_tspec == CHAR && 2756 tp->t_subt->t_const; 2757 } 2758 2759 static bool 2760 is_const_pointer(const tnode_t *tn) 2761 { 2762 const type_t *tp = before_conversion(tn)->tn_type; 2763 return tp->t_tspec == PTR && tp->t_subt->t_const; 2764 } 2765 2766 static void 2767 check_unconst_function(const type_t *lstp, const tnode_t *rn) 2768 { 2769 const char *function_name; 2770 2771 if (lstp->t_tspec == CHAR && !lstp->t_const && 2772 is_direct_function_call(rn, &function_name) && 2773 is_unconst_function(function_name) && 2774 rn->u.call->args_len >= 1 && 2775 is_const_char_pointer(rn->u.call->args[0])) { 2776 /* call to '%s' effectively discards 'const' from argument */ 2777 warning(346, function_name); 2778 } 2779 2780 if (!lstp->t_const && 2781 is_direct_function_call(rn, &function_name) && 2782 strcmp(function_name, "bsearch") == 0 && 2783 rn->u.call->args_len >= 2 && 2784 is_const_pointer(rn->u.call->args[1])) { 2785 /* call to '%s' effectively discards 'const' from argument */ 2786 warning(346, function_name); 2787 } 2788 } 2789 2790 static bool 2791 check_assign_void_pointer_compat(op_t op, int arg, 2792 const type_t *ltp, tspec_t lt, 2793 const type_t *lstp, tspec_t lst, 2794 const tnode_t *rn, 2795 const type_t *rtp, tspec_t rt, 2796 const type_t *rstp, tspec_t rst) 2797 { 2798 if (!(lt == PTR && rt == PTR && (lst == VOID || rst == VOID || 2799 types_compatible(lstp, rstp, 2800 true, false, NULL)))) 2801 return false; 2802 2803 /* compatible pointer types (qualifiers ignored) */ 2804 if (allow_c90 && 2805 ((!lstp->t_const && rstp->t_const) || 2806 (!lstp->t_volatile && rstp->t_volatile))) { 2807 /* left side has not all qualifiers of right */ 2808 switch (op) { 2809 case INIT: 2810 case RETURN: 2811 /* incompatible pointer types to '%s' and '%s' */ 2812 warning(182, type_name(lstp), type_name(rstp)); 2813 break; 2814 case FARG: 2815 /* converting '%s' to incompatible '%s' ... */ 2816 warning(153, 2817 type_name(rtp), type_name(ltp), arg); 2818 break; 2819 default: 2820 /* operands of '%s' have incompatible pointer ... */ 2821 warning(128, op_name(op), 2822 type_name(lstp), type_name(rstp)); 2823 break; 2824 } 2825 } 2826 2827 if (allow_c90) 2828 check_unconst_function(lstp, rn); 2829 2830 return true; 2831 } 2832 2833 static bool 2834 check_assign_pointer_integer(op_t op, int arg, 2835 const type_t *ltp, tspec_t lt, 2836 const type_t *rtp, tspec_t rt) 2837 { 2838 2839 if (!((lt == PTR && is_integer(rt)) || (is_integer(lt) && rt == PTR))) 2840 return false; 2841 2842 const char *lx = lt == PTR ? "pointer" : "integer"; 2843 const char *rx = rt == PTR ? "pointer" : "integer"; 2844 2845 switch (op) { 2846 case INIT: 2847 case RETURN: 2848 /* illegal combination of %s '%s' and %s '%s' */ 2849 warning(183, lx, type_name(ltp), rx, type_name(rtp)); 2850 break; 2851 case FARG: 2852 /* illegal combination of %s '%s' and %s '%s', arg #%d */ 2853 warning(154, 2854 lx, type_name(ltp), rx, type_name(rtp), arg); 2855 break; 2856 default: 2857 /* illegal combination of %s '%s' and %s '%s', op '%s' */ 2858 warning(123, 2859 lx, type_name(ltp), rx, type_name(rtp), op_name(op)); 2860 break; 2861 } 2862 return true; 2863 } 2864 2865 static bool 2866 check_assign_pointer(op_t op, int arg, 2867 const type_t *ltp, tspec_t lt, 2868 const type_t *rtp, tspec_t rt) 2869 { 2870 if (!(lt == PTR && rt == PTR)) 2871 return false; 2872 2873 if (op == FARG) 2874 /* converting '%s' to incompatible '%s' for ... */ 2875 warning(153, type_name(rtp), type_name(ltp), arg); 2876 else 2877 warn_incompatible_pointers(op, ltp, rtp); 2878 return true; 2879 } 2880 2881 static void 2882 warn_assign(op_t op, int arg, 2883 const type_t *ltp, tspec_t lt, 2884 const type_t *rtp, tspec_t rt) 2885 { 2886 switch (op) { 2887 case INIT: 2888 /* cannot initialize '%s' from '%s' */ 2889 error(185, type_name(ltp), type_name(rtp)); 2890 break; 2891 case RETURN: 2892 /* function has return type '%s' but returns '%s' */ 2893 error(211, type_name(ltp), type_name(rtp)); 2894 break; 2895 case FARG: 2896 /* passing '%s' to incompatible '%s', arg #%d */ 2897 warning(155, type_name(rtp), type_name(ltp), arg); 2898 break; 2899 default: 2900 warn_incompatible_types(op, ltp, lt, rtp, rt); 2901 break; 2902 } 2903 } 2904 2905 /* 2906 * Checks type compatibility for ASSIGN, INIT, FARG and RETURN 2907 * and prints warnings/errors if necessary. 2908 * Returns whether the types are (almost) compatible. 2909 */ 2910 static bool 2911 check_assign_types_compatible(op_t op, int arg, 2912 const tnode_t *ln, const tnode_t *rn) 2913 { 2914 tspec_t lt, rt, lst = NO_TSPEC, rst = NO_TSPEC; 2915 type_t *ltp, *rtp, *lstp = NULL, *rstp = NULL; 2916 2917 if ((lt = (ltp = ln->tn_type)->t_tspec) == PTR) 2918 lst = (lstp = ltp->t_subt)->t_tspec; 2919 if ((rt = (rtp = rn->tn_type)->t_tspec) == PTR) 2920 rst = (rstp = rtp->t_subt)->t_tspec; 2921 2922 if (lt == BOOL && is_scalar(rt)) /* C99 6.3.1.2 */ 2923 return true; 2924 2925 if (is_arithmetic(lt) && (is_arithmetic(rt) || rt == BOOL)) 2926 return true; 2927 2928 if (is_struct_or_union(lt) && is_struct_or_union(rt)) 2929 return ltp->u.sou == rtp->u.sou; 2930 2931 if (lt == PTR && is_null_pointer(rn)) { 2932 if (is_integer(rn->tn_type->t_tspec)) 2933 /* implicit conversion from integer 0 to pointer ... */ 2934 query_message(15, type_name(ltp)); 2935 return true; 2936 } 2937 2938 check_assign_void_pointer(op, arg, lt, lst, rt, rst); 2939 2940 if (check_assign_void_pointer_compat(op, arg, 2941 ltp, lt, lstp, lst, rn, rtp, rt, rstp, rst)) 2942 return true; 2943 2944 if (check_assign_pointer_integer(op, arg, ltp, lt, rtp, rt)) 2945 return true; 2946 2947 if (check_assign_pointer(op, arg, ltp, lt, rtp, rt)) 2948 return true; 2949 2950 warn_assign(op, arg, ltp, lt, rtp, rt); 2951 return false; 2952 } 2953 2954 static bool 2955 has_side_effect(const tnode_t *tn) /* NOLINT(misc-no-recursion) */ 2956 { 2957 op_t op = tn->tn_op; 2958 2959 if (modtab[op].m_has_side_effect) 2960 return true; 2961 2962 if (op == CVT && tn->tn_type->t_tspec == VOID) 2963 return has_side_effect(tn->u.ops.left); 2964 2965 /* XXX: Why not has_side_effect(tn->u.ops.left) as well? */ 2966 if (op == LOGAND || op == LOGOR) 2967 return has_side_effect(tn->u.ops.right); 2968 2969 /* XXX: Why not has_side_effect(tn->u.ops.left) as well? */ 2970 if (op == QUEST) 2971 return has_side_effect(tn->u.ops.right); 2972 2973 if (op == COLON || op == COMMA) { 2974 return has_side_effect(tn->u.ops.left) || 2975 has_side_effect(tn->u.ops.right); 2976 } 2977 2978 return false; 2979 } 2980 2981 static bool 2982 is_void_cast(const tnode_t *tn) 2983 { 2984 2985 return tn->tn_op == CVT && tn->tn_cast && 2986 tn->tn_type->t_tspec == VOID; 2987 } 2988 2989 static bool 2990 is_local_symbol(const tnode_t *tn) 2991 { 2992 2993 return tn->tn_op == LOAD && 2994 tn->u.ops.left->tn_op == NAME && 2995 tn->u.ops.left->u.sym->s_scl == AUTO; 2996 } 2997 2998 static bool 2999 is_int_constant_zero(const tnode_t *tn) 3000 { 3001 3002 return tn->tn_op == CON && 3003 tn->tn_type->t_tspec == INT && 3004 tn->u.value.u.integer == 0; 3005 } 3006 3007 static void 3008 check_null_effect(const tnode_t *tn) 3009 { 3010 3011 if (hflag && 3012 !has_side_effect(tn) && 3013 !(is_void_cast(tn) && is_local_symbol(tn->u.ops.left)) && 3014 !(is_void_cast(tn) && is_int_constant_zero(tn->u.ops.left))) { 3015 /* expression has null effect */ 3016 warning(129); 3017 } 3018 } 3019 3020 /* 3021 * Check the types for specific operators and type combinations. 3022 * 3023 * At this point, the operands already conform to the type requirements of 3024 * the operator, such as being integer, floating or scalar. 3025 */ 3026 static bool 3027 typeok_op(op_t op, int arg, 3028 const tnode_t *ln, const type_t *ltp, tspec_t lt, 3029 const tnode_t *rn, const type_t *rtp, tspec_t rt) 3030 { 3031 switch (op) { 3032 case ARROW: 3033 return typeok_arrow(lt); 3034 case POINT: 3035 return typeok_point(ln, ltp, lt); 3036 case INCBEF: 3037 case DECBEF: 3038 case INCAFT: 3039 case DECAFT: 3040 return typeok_incdec(op, ln, ltp); 3041 case INDIR: 3042 return typeok_indir(ltp, lt); 3043 case ADDR: 3044 return typeok_address(op, ln, ltp, lt); 3045 case PLUS: 3046 return typeok_plus(op, ltp, lt, rtp, rt); 3047 case MINUS: 3048 return typeok_minus(op, ltp, lt, rtp, rt); 3049 case SHL: 3050 typeok_shl(op, lt, rt); 3051 goto shift; 3052 case SHR: 3053 typeok_shr(op, ln, lt, rn, rt); 3054 shift: 3055 typeok_shift(ltp, lt, rn, rt); 3056 break; 3057 case LT: 3058 case LE: 3059 case GT: 3060 case GE: 3061 compare: 3062 return typeok_compare(op, ln, ltp, lt, rn, rtp, rt); 3063 case EQ: 3064 case NE: 3065 if (is_typeok_eq(ln, lt, rn, rt)) 3066 break; 3067 goto compare; 3068 case QUEST: 3069 return typeok_quest(lt, rn); 3070 case COLON: 3071 return typeok_colon(ln, ltp, lt, rn, rtp, rt); 3072 case ASSIGN: 3073 case INIT: 3074 case FARG: 3075 case RETURN: 3076 if (!check_assign_types_compatible(op, arg, ln, rn)) 3077 return false; 3078 goto assign; 3079 case MULASS: 3080 case DIVASS: 3081 case MODASS: 3082 goto assign; 3083 case ADDASS: 3084 case SUBASS: 3085 if ((lt == PTR && !is_integer(rt)) || rt == PTR) { 3086 warn_incompatible_types(op, ltp, lt, rtp, rt); 3087 return false; 3088 } 3089 goto assign; 3090 case SHLASS: 3091 goto assign; 3092 case SHRASS: 3093 if (pflag && !is_uinteger(lt) && 3094 !(!allow_c90 && is_uinteger(rt))) { 3095 /* bitwise '%s' on signed value possibly nonportable */ 3096 warning(117, op_name(op)); 3097 } 3098 goto assign; 3099 case ANDASS: 3100 case XORASS: 3101 case ORASS: 3102 assign: 3103 return typeok_assign(op, ln, ltp, lt); 3104 case COMMA: 3105 if (!modtab[ln->tn_op].m_has_side_effect) 3106 check_null_effect(ln); 3107 break; 3108 default: 3109 break; 3110 } 3111 return true; 3112 } 3113 3114 static void 3115 check_bad_enum_operation(op_t op, const tnode_t *ln, const tnode_t *rn) 3116 { 3117 3118 if (!eflag) 3119 return; 3120 3121 /* Allow enum in array indices. */ 3122 if (op == PLUS && 3123 ((ln->tn_type->t_is_enum && rn->tn_type->t_tspec == PTR) || 3124 (rn->tn_type->t_is_enum && ln->tn_type->t_tspec == PTR))) { 3125 return; 3126 } 3127 3128 /* dubious operation '%s' on enum */ 3129 warning(241, op_name(op)); 3130 } 3131 3132 static void 3133 check_enum_type_mismatch(op_t op, int arg, const tnode_t *ln, const tnode_t *rn) 3134 { 3135 const mod_t *mp = &modtab[op]; 3136 3137 if (ln->tn_type->u.enumer != rn->tn_type->u.enumer) { 3138 switch (op) { 3139 case INIT: 3140 /* enum type mismatch between '%s' and '%s' in ... */ 3141 warning(210, 3142 type_name(ln->tn_type), type_name(rn->tn_type)); 3143 break; 3144 case FARG: 3145 /* function expects '%s', passing '%s' for arg #%d */ 3146 warning(156, 3147 type_name(ln->tn_type), type_name(rn->tn_type), 3148 arg); 3149 break; 3150 case RETURN: 3151 /* function has return type '%s' but returns '%s' */ 3152 warning(211, 3153 type_name(ln->tn_type), type_name(rn->tn_type)); 3154 break; 3155 default: 3156 /* enum type mismatch: '%s' '%s' '%s' */ 3157 warning(130, type_name(ln->tn_type), op_name(op), 3158 type_name(rn->tn_type)); 3159 break; 3160 } 3161 } else if (Pflag && eflag && mp->m_comparison && op != EQ && op != NE) 3162 /* operator '%s' assumes that '%s' is ordered */ 3163 warning(243, op_name(op), type_name(ln->tn_type)); 3164 } 3165 3166 static void 3167 check_enum_int_mismatch(op_t op, int arg, const tnode_t *ln, const tnode_t *rn) 3168 { 3169 3170 if (!eflag) 3171 return; 3172 3173 switch (op) { 3174 case INIT: 3175 /* 3176 * Initialization with 0 is allowed. Otherwise, all implicit 3177 * initializations would need to be warned upon as well. 3178 */ 3179 if (!rn->tn_type->t_is_enum && rn->tn_op == CON && 3180 is_integer(rn->tn_type->t_tspec) && 3181 rn->u.value.u.integer == 0) { 3182 return; 3183 } 3184 /* initialization of '%s' with '%s' */ 3185 warning(277, type_name(ln->tn_type), type_name(rn->tn_type)); 3186 break; 3187 case FARG: 3188 /* combination of '%s' and '%s', arg #%d */ 3189 warning(278, 3190 type_name(ln->tn_type), type_name(rn->tn_type), arg); 3191 break; 3192 case RETURN: 3193 /* combination of '%s' and '%s' in return */ 3194 warning(279, type_name(ln->tn_type), type_name(rn->tn_type)); 3195 break; 3196 default: 3197 /* combination of '%s' and '%s', op '%s' */ 3198 warning(242, type_name(ln->tn_type), type_name(rn->tn_type), 3199 op_name(op)); 3200 break; 3201 } 3202 } 3203 3204 static void 3205 typeok_enum(op_t op, const mod_t *mp, int arg, 3206 const tnode_t *ln, const type_t *ltp, 3207 const tnode_t *rn, const type_t *rtp) 3208 { 3209 if (mp->m_bad_on_enum && 3210 (ltp->t_is_enum || (mp->m_binary && rtp->t_is_enum))) { 3211 check_bad_enum_operation(op, ln, rn); 3212 } else if (mp->m_valid_on_enum && 3213 (ltp->t_is_enum && rtp != NULL && rtp->t_is_enum)) { 3214 check_enum_type_mismatch(op, arg, ln, rn); 3215 } else if (mp->m_valid_on_enum && 3216 (ltp->t_is_enum || (rtp != NULL && rtp->t_is_enum))) { 3217 check_enum_int_mismatch(op, arg, ln, rn); 3218 } 3219 } 3220 3221 /* Perform most type checks. Return whether the types are ok. */ 3222 bool 3223 typeok(op_t op, int arg, const tnode_t *ln, const tnode_t *rn) 3224 { 3225 3226 const mod_t *mp = &modtab[op]; 3227 3228 type_t *ltp = ln->tn_type; 3229 tspec_t lt = ltp->t_tspec; 3230 3231 type_t *rtp = mp->m_binary ? rn->tn_type : NULL; 3232 tspec_t rt = mp->m_binary ? rtp->t_tspec : NO_TSPEC; 3233 3234 if (Tflag && !typeok_scalar_strict_bool(op, mp, arg, ln, rn)) 3235 return false; 3236 if (!typeok_scalar(op, mp, ltp, lt, rtp, rt)) 3237 return false; 3238 3239 if (!typeok_op(op, arg, ln, ltp, lt, rn, rtp, rt)) 3240 return false; 3241 3242 typeok_enum(op, mp, arg, ln, ltp, rn, rtp); 3243 return true; 3244 } 3245 3246 /* In traditional C, keep unsigned and promote FLOAT to DOUBLE. */ 3247 static tspec_t 3248 promote_trad(tspec_t t) 3249 { 3250 3251 if (t == UCHAR || t == USHORT) 3252 return UINT; 3253 if (t == CHAR || t == SCHAR || t == SHORT) 3254 return INT; 3255 if (t == FLOAT) 3256 return DOUBLE; 3257 if (t == ENUM) 3258 return INT; 3259 return t; 3260 } 3261 3262 /* 3263 * C99 6.3.1.1p2 requires for types with lower rank than int that "If an int 3264 * can represent all the values of the original type, the value is converted 3265 * to an int; otherwise it is converted to an unsigned int", and that "All 3266 * other types are unchanged by the integer promotions". 3267 */ 3268 static tspec_t 3269 promote_c90(const tnode_t *tn, tspec_t t, bool farg) 3270 { 3271 if (tn->tn_type->t_bitfield) { 3272 unsigned int width = tn->tn_type->t_bit_field_width; 3273 unsigned int int_width = size_in_bits(INT); 3274 // XXX: What about _Bool bit-fields, since C99? 3275 if (width < int_width) 3276 return INT; 3277 if (width == int_width) 3278 return is_uinteger(t) ? UINT : INT; 3279 return t; 3280 } 3281 3282 if (t == CHAR || t == SCHAR) 3283 return INT; 3284 if (t == UCHAR) 3285 return size_in_bits(CHAR) < size_in_bits(INT) ? INT : UINT; 3286 if (t == SHORT) 3287 return INT; 3288 if (t == USHORT) 3289 return size_in_bits(SHORT) < size_in_bits(INT) ? INT : UINT; 3290 if (t == ENUM) 3291 return INT; 3292 if (farg && t == FLOAT) 3293 return DOUBLE; 3294 return t; 3295 } 3296 3297 /* 3298 * Performs the "integer promotions" (C99 6.3.1.1p2), which convert small 3299 * integer types to either int or unsigned int. 3300 * 3301 * If allow_c90 is unset or the operand is a function argument with no type 3302 * information (no prototype or variable # of args), converts float to double. 3303 */ 3304 tnode_t * 3305 promote(op_t op, bool farg, tnode_t *tn) 3306 { 3307 3308 const type_t *otp = tn->tn_type; 3309 tspec_t ot = otp->t_tspec; 3310 if (!is_arithmetic(ot)) 3311 return tn; 3312 3313 tspec_t nt = allow_c90 ? promote_c90(tn, ot, farg) : promote_trad(ot); 3314 if (nt == ot) 3315 return tn; 3316 3317 type_t *ntp = expr_dup_type(gettyp(nt)); 3318 ntp->t_tspec = nt; 3319 ntp->t_is_enum = otp->t_is_enum; 3320 if (ntp->t_is_enum) 3321 ntp->u.enumer = otp->u.enumer; 3322 ntp->t_bitfield = otp->t_bitfield; 3323 if (ntp->t_bitfield) { 3324 ntp->t_bit_field_width = otp->t_bit_field_width; 3325 ntp->t_bit_field_offset = otp->t_bit_field_offset; 3326 } 3327 if (ntp->t_bitfield && is_uinteger(ot) && !is_uinteger(nt)) 3328 ntp->t_bit_field_width++; 3329 return convert(op, 0, ntp, tn); 3330 } 3331 3332 static void 3333 check_lossy_floating_to_integer_conversion( 3334 op_t op, int arg, const type_t *tp, const tnode_t *tn) 3335 { 3336 long double x = tn->u.value.u.floating; 3337 integer_constraints ic = ic_any(tp); 3338 if (is_uinteger(tp->t_tspec) 3339 ? x >= ic.umin && x <= ic.umax && x == (uint64_t)x 3340 : x >= ic.smin && x <= ic.smax && x == (int64_t)x) 3341 return; 3342 if (op == FARG) 3343 /* lossy conversion of %Lg to '%s', arg #%d */ 3344 warning(380, x, type_name(tp), arg); 3345 else 3346 /* lossy conversion of %Lg to '%s' */ 3347 warning(381, x, type_name(tp)); 3348 } 3349 3350 static void 3351 convert_integer_from_floating( 3352 op_t op, int arg, const type_t *tp, const tnode_t *tn) 3353 { 3354 3355 if (op == CVT) 3356 /* cast from floating point '%s' to integer '%s' */ 3357 query_message(2, type_name(tn->tn_type), type_name(tp)); 3358 else 3359 /* implicit conversion from floating point '%s' to ... */ 3360 query_message(1, type_name(tn->tn_type), type_name(tp)); 3361 if (tn->tn_op == CON) 3362 check_lossy_floating_to_integer_conversion(op, arg, tp, tn); 3363 } 3364 3365 static bool 3366 should_warn_about_prototype_conversion(tspec_t nt, 3367 tspec_t ot, const tnode_t *ptn) 3368 { 3369 3370 if (nt == ot) 3371 return false; 3372 3373 if (nt == ENUM && ot == INT) 3374 return false; 3375 3376 if (is_floating(nt) != is_floating(ot) || 3377 portable_rank_cmp(nt, ot) != 0) { 3378 /* representation and/or width change */ 3379 if (!is_integer(ot)) 3380 return true; 3381 /* 3382 * XXX: Investigate whether this rule makes sense; see 3383 * tests/usr.bin/xlint/lint1/platform_long.c. 3384 */ 3385 return portable_rank_cmp(ot, INT) > 0; 3386 } 3387 3388 if (!hflag) 3389 return false; 3390 3391 /* 3392 * If the types differ only in sign and the argument has the same 3393 * representation in both types, print no warning. 3394 */ 3395 if (ptn->tn_op == CON && is_integer(nt) && 3396 signed_type(nt) == signed_type(ot) && 3397 !msb(ptn->u.value.u.integer, ot)) 3398 return false; 3399 3400 return true; 3401 } 3402 3403 /* 3404 * Warn if a prototype causes a type conversion that is different from what 3405 * would happen to the same argument in the absence of a prototype. This 3406 * check is intended for code that needs to stay compatible with pre-C90 C. 3407 * 3408 * Errors/warnings about illegal type combinations are already printed 3409 * in check_assign_types_compatible(). 3410 */ 3411 static void 3412 check_prototype_conversion(int arg, tspec_t nt, tspec_t ot, type_t *tp, 3413 tnode_t *tn) 3414 { 3415 3416 if (!is_arithmetic(nt) || !is_arithmetic(ot)) 3417 return; 3418 3419 /* 3420 * If the type of the formal parameter is char/short, a warning would 3421 * be useless, because functions declared the old style can't expect 3422 * char/short arguments. 3423 */ 3424 if (nt == CHAR || nt == SCHAR || nt == UCHAR || 3425 nt == SHORT || nt == USHORT) 3426 return; 3427 3428 tnode_t *ptn = promote(NOOP, true, tn); 3429 ot = ptn->tn_type->t_tspec; 3430 3431 if (should_warn_about_prototype_conversion(nt, ot, ptn)) { 3432 /* argument %d is converted from '%s' to '%s' ... */ 3433 warning(259, arg, type_name(tn->tn_type), type_name(tp)); 3434 } 3435 } 3436 3437 /* 3438 * When converting a large integer type to a small integer type, in some 3439 * cases the value of the actual expression is further restricted than the 3440 * type bounds, such as in (expr & 0xFF) or (expr % 100) or (expr >> 24). 3441 */ 3442 static bool 3443 can_represent(const type_t *tp, const tnode_t *tn) 3444 { 3445 3446 debug_step("%s: type '%s'", __func__, type_name(tp)); 3447 debug_node(tn); 3448 3449 uint64_t nmask = value_bits(width_in_bits(tp)); 3450 if (!is_uinteger(tp->t_tspec)) 3451 nmask >>= 1; 3452 3453 integer_constraints c = ic_expr(tn); 3454 if ((~c.bclr & ~nmask) == 0) 3455 return true; 3456 3457 integer_constraints tpc = ic_any(tp); 3458 if (is_uinteger(tp->t_tspec) 3459 ? tpc.umin <= c.umin && tpc.umax >= c.umax 3460 : tpc.smin <= c.smin && tpc.smax >= c.smax) 3461 return true; 3462 3463 return false; 3464 } 3465 3466 static bool 3467 should_warn_about_integer_conversion(const type_t *ntp, tspec_t nt, 3468 const tnode_t *otn, tspec_t ot) 3469 { 3470 3471 // XXX: The portable_rank_cmp aims at portable mode, independent of the 3472 // current platform, while can_represent acts on the actual type sizes 3473 // from the current platform. This mix is inconsistent, but anything 3474 // else would make the exact conditions too complicated to grasp. 3475 if (aflag > 0 && portable_rank_cmp(nt, ot) < 0) { 3476 if (ot == LONG || ot == ULONG 3477 || ot == LLONG || ot == ULLONG 3478 #ifdef INT128_SIZE 3479 || ot == INT128 || ot == UINT128 3480 #endif 3481 || aflag > 1) 3482 return !can_represent(ntp, otn); 3483 } 3484 return false; 3485 } 3486 3487 static void 3488 convert_integer_from_integer(op_t op, int arg, tspec_t nt, tspec_t ot, 3489 type_t *tp, tnode_t *tn) 3490 { 3491 3492 if (tn->tn_op == CON) 3493 return; 3494 3495 if (op == CVT) 3496 return; 3497 3498 if (Pflag && pflag && aflag > 0 && 3499 portable_rank_cmp(nt, ot) > 0 && 3500 is_uinteger(nt) != is_uinteger(ot)) { 3501 if (op == FARG) 3502 /* conversion to '%s' may sign-extend ... */ 3503 warning(297, type_name(tp), arg); 3504 else 3505 /* conversion to '%s' may sign-extend ... */ 3506 warning(131, type_name(tp)); 3507 } 3508 3509 if (Pflag && portable_rank_cmp(nt, ot) > 0 && 3510 (tn->tn_op == PLUS || tn->tn_op == MINUS || tn->tn_op == MULT || 3511 tn->tn_op == SHL)) { 3512 /* suggest cast from '%s' to '%s' on op '%s' to ... */ 3513 warning(324, type_name(gettyp(ot)), type_name(tp), 3514 op_name(tn->tn_op)); 3515 } 3516 3517 if (should_warn_about_integer_conversion(tp, nt, tn, ot)) { 3518 if (op == FARG) { 3519 /* conversion from '%s' to '%s' may lose ... */ 3520 warning(298, 3521 type_name(tn->tn_type), type_name(tp), arg); 3522 } else { 3523 /* conversion from '%s' to '%s' may lose accuracy */ 3524 warning(132, 3525 type_name(tn->tn_type), type_name(tp)); 3526 } 3527 } 3528 3529 if (any_query_enabled && is_uinteger(nt) != is_uinteger(ot)) 3530 /* implicit conversion changes sign from '%s' to '%s' */ 3531 query_message(3, type_name(tn->tn_type), type_name(tp)); 3532 } 3533 3534 static void 3535 convert_integer_from_pointer(op_t op, tspec_t nt, type_t *tp, tnode_t *tn) 3536 { 3537 3538 if (tn->tn_op == CON) 3539 return; 3540 if (op != CVT) 3541 return; /* We already got an error. */ 3542 if (portable_rank_cmp(nt, PTR) >= 0) 3543 return; 3544 3545 if (pflag && size_in_bits(nt) >= size_in_bits(PTR)) { 3546 /* conversion of pointer to '%s' may lose bits */ 3547 warning(134, type_name(tp)); 3548 } else { 3549 /* conversion of pointer to '%s' loses bits */ 3550 warning(133, type_name(tp)); 3551 } 3552 } 3553 3554 static bool 3555 struct_starts_with(const type_t *struct_tp, const type_t *member_tp) 3556 { 3557 3558 return struct_tp->u.sou->sou_first_member != NULL && 3559 types_compatible(struct_tp->u.sou->sou_first_member->s_type, 3560 member_tp, true, false, NULL); 3561 } 3562 3563 static bool 3564 is_byte_array(const type_t *tp) 3565 { 3566 3567 return tp->t_tspec == ARRAY && 3568 (tp->t_subt->t_tspec == CHAR || tp->t_subt->t_tspec == UCHAR); 3569 } 3570 3571 static bool 3572 union_contains(const type_t *utp, const type_t *mtp) 3573 { 3574 for (const sym_t *mem = utp->u.sou->sou_first_member; 3575 mem != NULL; mem = mem->s_next) { 3576 if (types_compatible(mem->s_type, mtp, true, false, NULL)) 3577 return true; 3578 } 3579 return false; 3580 } 3581 3582 static bool 3583 should_warn_about_pointer_cast(const type_t *nstp, tspec_t nst, 3584 const type_t *ostp, tspec_t ost) 3585 { 3586 3587 while (nst == ARRAY) 3588 nstp = nstp->t_subt, nst = nstp->t_tspec; 3589 while (ost == ARRAY) 3590 ostp = ostp->t_subt, ost = ostp->t_tspec; 3591 3592 if (nst == STRUCT && ost == STRUCT && 3593 (struct_starts_with(nstp, ostp) || 3594 struct_starts_with(ostp, nstp))) 3595 return false; 3596 3597 if (is_incomplete(nstp) || is_incomplete(ostp)) 3598 return false; 3599 3600 if (nst == CHAR || nst == UCHAR) 3601 return false; /* for the sake of traditional C code */ 3602 if (ost == CHAR || ost == UCHAR) 3603 return false; /* for the sake of traditional C code */ 3604 3605 /* Allow cast between pointers to sockaddr variants. */ 3606 if (nst == STRUCT && ost == STRUCT) { 3607 const sym_t *nmem = nstp->u.sou->sou_first_member; 3608 const sym_t *omem = ostp->u.sou->sou_first_member; 3609 while (nmem != NULL && omem != NULL && 3610 types_compatible(nmem->s_type, omem->s_type, 3611 true, false, NULL)) 3612 nmem = nmem->s_next, omem = omem->s_next; 3613 if (nmem != NULL && is_byte_array(nmem->s_type)) 3614 return false; 3615 if (omem != NULL && is_byte_array(omem->s_type)) 3616 return false; 3617 if (nmem == NULL && omem == NULL) 3618 return false; 3619 } 3620 3621 if (nst == UNION || ost == UNION) { 3622 const type_t *union_tp = nst == UNION ? nstp : ostp; 3623 const type_t *other_tp = nst == UNION ? ostp : nstp; 3624 if (union_contains(union_tp, other_tp)) 3625 return false; 3626 } 3627 3628 if (is_struct_or_union(nst) && is_struct_or_union(ost)) 3629 return nstp->u.sou != ostp->u.sou; 3630 3631 enum rank_kind rk1 = type_properties(nst)->tt_rank_kind; 3632 enum rank_kind rk2 = type_properties(ost)->tt_rank_kind; 3633 if (rk1 != rk2 || rk1 == RK_NONE) 3634 return true; 3635 3636 return portable_rank_cmp(nst, ost) != 0; 3637 } 3638 3639 static void 3640 convert_pointer_from_pointer(type_t *ntp, tnode_t *tn) 3641 { 3642 const type_t *nstp = ntp->t_subt; 3643 const type_t *otp = tn->tn_type; 3644 const type_t *ostp = otp->t_subt; 3645 tspec_t nst = nstp->t_tspec; 3646 tspec_t ost = ostp->t_tspec; 3647 3648 if (nst == VOID || ost == VOID) { 3649 /* TODO: C99 behaves like C90 here. */ 3650 if (!allow_trad && !allow_c99 && (nst == FUNC || ost == FUNC)) { 3651 const char *nts, *ots; 3652 /* null pointers are already handled in convert() */ 3653 *(nst == FUNC ? &nts : &ots) = "function pointer"; 3654 *(nst == VOID ? &nts : &ots) = "'void *'"; 3655 /* conversion of %s to %s requires a cast */ 3656 warning(303, ots, nts); 3657 } 3658 return; 3659 } 3660 if (nst == FUNC && ost == FUNC) 3661 return; 3662 if (nst == FUNC || ost == FUNC) { 3663 /* converting '%s' to '%s' is questionable */ 3664 warning(229, type_name(otp), type_name(ntp)); 3665 return; 3666 } 3667 3668 if (hflag && alignment(nstp) > alignment(ostp) && 3669 ost != CHAR && ost != UCHAR && 3670 !is_incomplete(ostp) && 3671 !(nst == UNION && union_contains(nstp, ostp))) { 3672 /* converting '%s' to '%s' increases alignment ... */ 3673 warning(135, type_name(otp), type_name(ntp), 3674 alignment(ostp), alignment(nstp)); 3675 } 3676 3677 if (cflag && should_warn_about_pointer_cast(nstp, nst, ostp, ost)) { 3678 /* pointer cast from '%s' to '%s' may be troublesome */ 3679 warning(247, type_name(otp), type_name(ntp)); 3680 } 3681 } 3682 3683 /* 3684 * Insert a conversion operator, which converts the type of the node 3685 * to another given type. 3686 * 3687 * Possible values for 'op': 3688 * CVT a cast-expression 3689 * binary integer promotion for one of the operands, or a usual 3690 * arithmetic conversion 3691 * binary plain or compound assignments to bit-fields 3692 * FARG 'arg' is the number of the parameter (used for warnings) 3693 * NOOP several other implicit conversions 3694 * ... 3695 */ 3696 tnode_t * 3697 convert(op_t op, int arg, type_t *tp, tnode_t *tn) 3698 { 3699 tspec_t nt = tp->t_tspec; 3700 tspec_t ot = tn->tn_type->t_tspec; 3701 3702 if (allow_trad && allow_c90 && op == FARG) 3703 check_prototype_conversion(arg, nt, ot, tp, tn); 3704 3705 if (nt == BOOL) { 3706 /* No further checks. */ 3707 3708 } else if (is_integer(nt)) { 3709 if (ot == BOOL) { 3710 /* No further checks. */ 3711 } else if (is_integer(ot)) 3712 convert_integer_from_integer(op, arg, nt, ot, tp, tn); 3713 else if (is_floating(ot)) 3714 convert_integer_from_floating(op, arg, tp, tn); 3715 else if (ot == PTR) 3716 convert_integer_from_pointer(op, nt, tp, tn); 3717 3718 } else if (is_floating(nt)) { 3719 if (is_integer(ot) && op != CVT) { 3720 /* implicit conversion from integer '%s' to ... */ 3721 query_message(19, 3722 type_name(tn->tn_type), type_name(tp)); 3723 } 3724 3725 } else if (nt == PTR) { 3726 if (is_null_pointer(tn)) { 3727 /* a null pointer may be assigned to any pointer. */ 3728 } else if (ot == PTR && op == CVT) 3729 convert_pointer_from_pointer(tp, tn); 3730 } 3731 3732 tnode_t *ntn = expr_alloc_tnode(); 3733 ntn->tn_op = CVT; 3734 ntn->tn_type = tp; 3735 ntn->tn_cast = op == CVT; 3736 ntn->tn_sys |= tn->tn_sys; 3737 ntn->u.ops.right = NULL; 3738 if (tn->tn_op != CON || nt == VOID) { 3739 ntn->u.ops.left = tn; 3740 } else { 3741 ntn->tn_op = CON; 3742 convert_constant(op, arg, ntn->tn_type, &ntn->u.value, 3743 &tn->u.value); 3744 } 3745 3746 return ntn; 3747 } 3748 3749 static void 3750 convert_constant_from_floating(op_t op, int arg, const type_t *ntp, 3751 tspec_t nt, val_t *nv, val_t *ov) 3752 { 3753 long double max = 0.0, min = 0.0; 3754 3755 switch (nt) { 3756 case CHAR: 3757 max = TARG_CHAR_MAX; min = TARG_CHAR_MIN; break; 3758 case UCHAR: 3759 max = TARG_UCHAR_MAX; min = 0; break; 3760 case SCHAR: 3761 max = TARG_SCHAR_MAX; min = TARG_SCHAR_MIN; break; 3762 case SHORT: 3763 max = TARG_SHRT_MAX; min = TARG_SHRT_MIN; break; 3764 case USHORT: 3765 max = TARG_USHRT_MAX; min = 0; break; 3766 case ENUM: 3767 case INT: 3768 max = TARG_INT_MAX; min = TARG_INT_MIN; break; 3769 case UINT: 3770 max = TARG_UINT_MAX; min = 0; break; 3771 case LONG: 3772 max = TARG_LONG_MAX; min = TARG_LONG_MIN; break; 3773 case ULONG: 3774 max = TARG_ULONG_MAX; min = 0; break; 3775 case LLONG: 3776 max = LLONG_MAX; min = LLONG_MIN; break; 3777 case ULLONG: 3778 max = ULLONG_MAX; min = 0; break; 3779 case FLOAT: 3780 case FCOMPLEX: 3781 max = FLT_MAX; min = -FLT_MAX; break; 3782 case DOUBLE: 3783 case DCOMPLEX: 3784 max = DBL_MAX; min = -DBL_MAX; break; 3785 case LDOUBLE: 3786 case LCOMPLEX: 3787 /* LINTED 248; see floating_error_value. */ 3788 max = LDBL_MAX; min = -max; break; 3789 default: 3790 lint_assert(/*CONSTCOND*/false); 3791 } 3792 if (ov->u.floating > max || ov->u.floating < min) { 3793 lint_assert(nt != LDOUBLE); 3794 const char *ot_name = type_name(gettyp(ov->v_tspec)); 3795 const char *nt_name = type_name(ntp); 3796 if (is_integer(nt)) 3797 goto after_warning; 3798 if (op == FARG) 3799 /* conversion of '%s' to '%s' is out of range, ... */ 3800 warning(295, ot_name, nt_name, arg); 3801 else 3802 /* conversion of '%s' to '%s' is out of range */ 3803 warning(119, ot_name, nt_name); 3804 after_warning: 3805 ov->u.floating = ov->u.floating > 0 ? max : min; 3806 } 3807 3808 if (nt == FLOAT || nt == FCOMPLEX) 3809 nv->u.floating = (float)ov->u.floating; 3810 else if (nt == DOUBLE || nt == DCOMPLEX) 3811 nv->u.floating = (double)ov->u.floating; 3812 else if (nt == LDOUBLE || nt == LCOMPLEX) 3813 nv->u.floating = ov->u.floating; 3814 else 3815 nv->u.integer = (int64_t)ov->u.floating; 3816 } 3817 3818 static bool 3819 convert_constant_to_floating(tspec_t nt, val_t *nv, 3820 tspec_t ot, const val_t *v) 3821 { 3822 if (nt == FLOAT) { 3823 nv->u.floating = (ot == PTR || is_uinteger(ot)) ? 3824 (float)(uint64_t)v->u.integer : (float)v->u.integer; 3825 } else if (nt == DOUBLE) { 3826 nv->u.floating = (ot == PTR || is_uinteger(ot)) ? 3827 (double)(uint64_t)v->u.integer : (double)v->u.integer; 3828 } else if (nt == LDOUBLE) { 3829 nv->u.floating = (ot == PTR || is_uinteger(ot)) 3830 ? (long double)(uint64_t)v->u.integer 3831 : (long double)v->u.integer; 3832 } else 3833 return false; 3834 return true; 3835 } 3836 3837 /* 3838 * Print a warning if bits which were set are lost due to the conversion. 3839 * This can happen with operator ORASS only. 3840 */ 3841 static void 3842 convert_constant_check_range_bitor(size_t nsz, size_t osz, const val_t *v, 3843 uint64_t xmask, op_t op) 3844 { 3845 if (nsz < osz && (v->u.integer & xmask) != 0) 3846 /* constant truncated by conversion, op '%s' */ 3847 warning(306, op_name(op)); 3848 } 3849 3850 static void 3851 convert_constant_check_range_bitand(size_t nsz, size_t osz, 3852 uint64_t xmask, const val_t *nv, 3853 tspec_t ot, const val_t *v, 3854 const type_t *tp, op_t op) 3855 { 3856 if (nsz > osz && 3857 (nv->u.integer & bit((unsigned int)(osz - 1))) != 0 && 3858 (nv->u.integer & xmask) != xmask) { 3859 /* extra bits set to 0 in conversion of '%s' to '%s', ... */ 3860 warning(309, type_name(gettyp(ot)), 3861 type_name(tp), op_name(op)); 3862 } else if (nsz < osz && 3863 (v->u.integer & xmask) != xmask && 3864 (v->u.integer & xmask) != 0) 3865 /* constant truncated by conversion, op '%s' */ 3866 warning(306, op_name(op)); 3867 } 3868 3869 static void 3870 convert_constant_check_range_signed(op_t op, int arg, 3871 const type_t *ntp, int64_t ov) 3872 { 3873 if (op == ASSIGN) 3874 /* assignment of negative constant %lld to unsigned ... */ 3875 warning(164, (long long)ov, type_name(ntp)); 3876 else if (op == INIT) 3877 /* initialization of unsigned type '%s' with negative ... */ 3878 warning(221, type_name(ntp), (long long)ov); 3879 else if (op == FARG) 3880 /* conversion of negative constant %lld to unsigned ... */ 3881 warning(296, (long long)ov, type_name(ntp), arg); 3882 else if (modtab[op].m_comparison) { 3883 /* handled by check_integer_comparison() */ 3884 } else 3885 /* conversion of negative constant %lld to unsigned ... */ 3886 warning(222, (long long)ov, type_name(ntp)); 3887 } 3888 3889 /* 3890 * Loss of significant bit(s). All truncated bits of unsigned types or all 3891 * truncated bits plus the msb of the target for signed types are considered 3892 * to be significant bits. Loss of significant bits means that at least one 3893 * of the bits was set in an unsigned type or that at least one but not all 3894 * of the bits was set in a signed type. Loss of significant bits means that 3895 * it is not possible, also not with necessary casts, to convert back to the 3896 * original type. An example for a necessary cast is: 3897 * char c; int i; c = 128; 3898 * i = c; ** yields -128 ** 3899 * i = (unsigned char)c; ** yields 128 ** 3900 */ 3901 static void 3902 warn_constant_check_range_truncated(op_t op, int arg, const type_t *tp, 3903 tspec_t ot) 3904 { 3905 if (op == ASSIGN && tp->t_bitfield) 3906 /* precision lost in bit-field assignment */ 3907 warning(166); 3908 else if (op == ASSIGN) 3909 /* constant truncated by assignment */ 3910 warning(165); 3911 else if (op == INIT && tp->t_bitfield) 3912 /* bit-field initializer does not fit */ 3913 warning(180); 3914 else if (op == INIT) 3915 /* initializer does not fit */ 3916 warning(178); 3917 else if (op == CASE) 3918 /* case label affected by conversion */ 3919 warning(196); 3920 else if (op == FARG) 3921 /* conversion of '%s' to '%s' is out of range, arg #%d */ 3922 warning(295, type_name(gettyp(ot)), type_name(tp), arg); 3923 else 3924 /* conversion of '%s' to '%s' is out of range */ 3925 warning(119, type_name(gettyp(ot)), type_name(tp)); 3926 } 3927 3928 static void 3929 warn_constant_check_range_loss(op_t op, int arg, const type_t *tp, 3930 tspec_t ot) 3931 { 3932 if (op == ASSIGN && tp->t_bitfield) 3933 /* precision lost in bit-field assignment */ 3934 warning(166); 3935 else if (op == INIT && tp->t_bitfield) 3936 /* bit-field initializer out of range */ 3937 warning(11); 3938 else if (op == CASE) 3939 /* case label affected by conversion */ 3940 warning(196); 3941 else if (op == FARG) 3942 /* conversion of '%s' to '%s' is out of range, arg #%d */ 3943 warning(295, type_name(gettyp(ot)), type_name(tp), arg); 3944 else 3945 /* conversion of '%s' to '%s' is out of range */ 3946 warning(119, type_name(gettyp(ot)), type_name(tp)); 3947 } 3948 3949 static void 3950 convert_constant_check_range(tspec_t ot, const type_t *tp, tspec_t nt, 3951 op_t op, int arg, const val_t *v, val_t *nv) 3952 { 3953 unsigned int obitsz, nbitsz; 3954 uint64_t xmask, xmsk1; 3955 3956 obitsz = size_in_bits(ot); 3957 nbitsz = tp->t_bitfield ? tp->t_bit_field_width : size_in_bits(nt); 3958 xmask = value_bits(nbitsz) ^ value_bits(obitsz); 3959 xmsk1 = value_bits(nbitsz) ^ value_bits(obitsz - 1); 3960 if (op == ORASS || op == BITOR || op == BITXOR) { 3961 convert_constant_check_range_bitor( 3962 nbitsz, obitsz, v, xmask, op); 3963 } else if (op == ANDASS || op == BITAND) { 3964 convert_constant_check_range_bitand( 3965 nbitsz, obitsz, xmask, nv, ot, v, tp, op); 3966 } else if (nt != PTR && is_uinteger(nt) && 3967 ot != PTR && !is_uinteger(ot) && 3968 v->u.integer < 0) 3969 convert_constant_check_range_signed(op, arg, 3970 tp, v->u.integer); 3971 else if (nv->u.integer != v->u.integer && nbitsz <= obitsz && 3972 (v->u.integer & xmask) != 0 && 3973 (is_uinteger(ot) || (v->u.integer & xmsk1) != xmsk1)) 3974 warn_constant_check_range_truncated(op, arg, tp, ot); 3975 else if (nv->u.integer != v->u.integer) 3976 warn_constant_check_range_loss(op, arg, tp, ot); 3977 } 3978 3979 /* Converts a typed constant to a constant of another type. */ 3980 void 3981 convert_constant(op_t op, int arg, const type_t *ntp, val_t *nv, val_t *ov) 3982 { 3983 /* 3984 * TODO: make 'ov' const; the name of this function does not suggest 3985 * that it modifies 'ov'. 3986 */ 3987 tspec_t ot = ov->v_tspec; 3988 tspec_t nt = nv->v_tspec = ntp->t_tspec; 3989 bool range_check = false; 3990 3991 if (nt == BOOL) { /* C99 6.3.1.2 */ 3992 nv->v_unsigned_since_c90 = false; 3993 nv->u.integer = is_nonzero_val(ov) ? 1 : 0; 3994 return; 3995 } 3996 3997 if (ot == FLOAT || ot == DOUBLE || ot == LDOUBLE) 3998 convert_constant_from_floating(op, arg, ntp, nt, nv, ov); 3999 else if (!convert_constant_to_floating(nt, nv, ot, ov)) { 4000 range_check = true; /* Check for lost precision. */ 4001 nv->u.integer = ov->u.integer; 4002 } 4003 4004 if (allow_trad && allow_c90 && ov->v_unsigned_since_c90 && 4005 (is_floating(nt) || ( 4006 (is_integer(nt) && !is_uinteger(nt) && 4007 portable_rank_cmp(nt, ot) > 0)))) { 4008 /* C90 treats constant as unsigned */ 4009 warning(157); 4010 ov->v_unsigned_since_c90 = false; 4011 } 4012 4013 if (is_integer(nt)) { 4014 unsigned int size = ntp->t_bitfield 4015 ? ntp->t_bit_field_width : size_in_bits(nt); 4016 nv->u.integer = convert_integer(nv->u.integer, nt, size); 4017 } 4018 4019 if (range_check && op != CVT) 4020 convert_constant_check_range(ot, ntp, nt, op, arg, ov, nv); 4021 } 4022 4023 tnode_t * 4024 build_sizeof(const type_t *tp) 4025 { 4026 unsigned int size_in_bytes = type_size_in_bits(tp) / CHAR_SIZE; 4027 tnode_t *tn = build_integer_constant(SIZEOF_TSPEC, size_in_bytes); 4028 tn->tn_system_dependent = true; 4029 debug_step("build_sizeof '%s' = %u", type_name(tp), size_in_bytes); 4030 return tn; 4031 } 4032 4033 tnode_t * 4034 build_offsetof(const type_t *tp, designation dn) 4035 { 4036 unsigned int offset_in_bits = 0; 4037 4038 if (!is_struct_or_union(tp->t_tspec)) { 4039 /* unacceptable operand of '%s' */ 4040 error(111, "offsetof"); 4041 goto proceed; 4042 } 4043 for (size_t i = 0; i < dn.dn_len; i++) { 4044 const designator *dr = dn.dn_items + i; 4045 if (dr->dr_kind == DK_SUBSCRIPT) { 4046 if (tp->t_tspec != ARRAY) 4047 goto proceed; /* silent error */ 4048 tp = tp->t_subt; 4049 offset_in_bits += (unsigned) dr->dr_subscript 4050 * type_size_in_bits(tp); 4051 } else { 4052 if (!is_struct_or_union(tp->t_tspec)) 4053 goto proceed; /* silent error */ 4054 const char *name = dr->dr_member->s_name; 4055 sym_t *mem = find_member(tp->u.sou, name); 4056 if (mem == NULL) { 4057 /* type '%s' does not have member '%s' */ 4058 error(101, name, type_name(tp)); 4059 goto proceed; 4060 } 4061 tp = mem->s_type; 4062 offset_in_bits += mem->u.s_member.sm_offset_in_bits; 4063 } 4064 } 4065 free(dn.dn_items); 4066 4067 proceed:; 4068 unsigned int offset_in_bytes = offset_in_bits / CHAR_SIZE; 4069 tnode_t *tn = build_integer_constant(SIZEOF_TSPEC, offset_in_bytes); 4070 tn->tn_system_dependent = true; 4071 return tn; 4072 } 4073 4074 unsigned int 4075 type_size_in_bits(const type_t *tp) 4076 { 4077 4078 unsigned int elem = 1; 4079 bool flex = false; 4080 lint_assert(tp != NULL); 4081 while (tp->t_tspec == ARRAY) { 4082 flex = true; /* allow c99 flex arrays [] [0] */ 4083 elem *= tp->u.dimension; 4084 tp = tp->t_subt; 4085 } 4086 if (elem == 0 && !flex) { 4087 /* cannot take size/alignment of incomplete type */ 4088 error(143); 4089 elem = 1; 4090 } 4091 4092 unsigned int elsz; 4093 switch (tp->t_tspec) { 4094 case VOID: 4095 /* cannot take size/alignment of void */ 4096 error(146); 4097 elsz = 1; 4098 break; 4099 case FUNC: 4100 /* cannot take size/alignment of function type '%s' */ 4101 error(144, type_name(tp)); 4102 elsz = 1; 4103 break; 4104 case STRUCT: 4105 case UNION: 4106 if (is_incomplete(tp)) { 4107 /* cannot take size/alignment of incomplete type */ 4108 error(143); 4109 elsz = 1; 4110 } else 4111 elsz = tp->u.sou->sou_size_in_bits; 4112 break; 4113 case ENUM: 4114 if (is_incomplete(tp)) { 4115 /* cannot take size/alignment of incomplete type */ 4116 warning(143); 4117 } 4118 /* FALLTHROUGH */ 4119 default: 4120 if (tp->t_bitfield) 4121 /* cannot take size/alignment of bit-field */ 4122 error(145); 4123 elsz = size_in_bits(tp->t_tspec); 4124 lint_assert(elsz > 0); 4125 break; 4126 } 4127 4128 return elem * elsz; 4129 } 4130 4131 /* C11 6.5.3.4, GCC */ 4132 tnode_t * 4133 build_alignof(const type_t *tp) 4134 { 4135 if (tp->t_tspec == FUNC) { 4136 /* cannot take size/alignment of function type '%s' */ 4137 error(144, type_name(tp)); 4138 return NULL; 4139 } 4140 if (tp->t_tspec == VOID) { 4141 /* cannot take size/alignment of void */ 4142 error(146); 4143 return NULL; 4144 } 4145 if (is_incomplete(tp)) { 4146 /* cannot take size/alignment of incomplete type */ 4147 error(143); 4148 return NULL; 4149 } 4150 if (tp->t_bitfield) { 4151 /* cannot take size/alignment of bit-field */ 4152 error(145); 4153 return NULL; 4154 } 4155 return build_integer_constant(SIZEOF_TSPEC, (int64_t)alignment(tp)); 4156 } 4157 4158 static tnode_t * 4159 cast_to_union(tnode_t *otn, bool sys, type_t *ntp) 4160 { 4161 4162 if (!allow_gcc) { 4163 /* union cast is a GCC extension */ 4164 error(328); 4165 return NULL; 4166 } 4167 4168 for (const sym_t *m = ntp->u.sou->sou_first_member; 4169 m != NULL; m = m->s_next) { 4170 if (types_compatible(m->s_type, otn->tn_type, 4171 false, false, NULL)) { 4172 tnode_t *ntn = build_op(CVT, sys, ntp, otn, NULL); 4173 ntn->tn_cast = true; 4174 return ntn; 4175 } 4176 } 4177 4178 /* type '%s' is not a member of '%s' */ 4179 error(329, type_name(otn->tn_type), type_name(ntp)); 4180 return NULL; 4181 } 4182 4183 // In GCC mode, allow 'nullptr + offset' as a constant expression. 4184 static tnode_t * 4185 null_pointer_offset(tnode_t *tn) 4186 { 4187 uint64_t off = 0; 4188 const tnode_t *n = tn; 4189 while ((n->tn_op == PLUS || n->tn_op == MINUS) 4190 && is_integer(n->u.ops.right->tn_type->t_tspec)) { 4191 off += (uint64_t)n->u.ops.right->u.value.u.integer; 4192 n = n->u.ops.left; 4193 } 4194 if (n->tn_type->t_tspec == PTR 4195 && n->tn_op == ADDR 4196 && n->u.ops.left->tn_op == INDIR 4197 && n->u.ops.left->u.ops.left->tn_op == CON 4198 && n->u.ops.left->u.ops.left->tn_type->t_tspec == PTR) { 4199 off += (uint64_t)n->u.ops.left->u.ops.left->u.value.u.integer; 4200 return build_integer_constant(SIZEOF_TSPEC, (int64_t)off); 4201 } 4202 return tn; 4203 } 4204 4205 tnode_t * 4206 cast(tnode_t *tn, bool sys, type_t *tp) 4207 { 4208 4209 if (tn == NULL) 4210 return NULL; 4211 4212 tn = cconv(tn); 4213 4214 lint_assert(tp != NULL); 4215 tspec_t nt = tp->t_tspec; 4216 tspec_t ot = tn->tn_type->t_tspec; 4217 4218 if (nt == VOID) { 4219 /* 4220 * C90 6.3.4, C99 6.5.4p2 and C11 6.5.4p2 allow any type to be 4221 * cast to void. The only other allowed casts are from a 4222 * scalar type to a scalar type. 4223 */ 4224 } else if (nt == UNION) 4225 return cast_to_union(tn, sys, tp); 4226 else if (nt == STRUCT || nt == ARRAY || nt == FUNC) { 4227 /* Casting to a struct is an undocumented GCC extension. */ 4228 if (!(allow_gcc && nt == STRUCT)) 4229 goto invalid_cast; 4230 } else if (is_struct_or_union(ot)) 4231 goto invalid_cast; 4232 else if (ot == VOID) { 4233 /* improper cast of void expression */ 4234 error(148); 4235 return NULL; 4236 } else if (is_integer(nt) && is_scalar(ot)) { 4237 tn = null_pointer_offset(tn); 4238 } else if (is_floating(nt) && is_arithmetic(ot)) { 4239 /* ok */ 4240 } else if (nt == PTR && is_integer(ot)) { 4241 /* ok */ 4242 } else if (nt == PTR && ot == PTR) { 4243 if (!tp->t_subt->t_const && tn->tn_type->t_subt->t_const) { 4244 if (hflag) 4245 /* cast discards 'const' from type '%s' */ 4246 warning(275, type_name(tn->tn_type)); 4247 } 4248 } else 4249 goto invalid_cast; 4250 4251 if (any_query_enabled 4252 && types_compatible(tp, tn->tn_type, false, false, NULL)) 4253 /* no-op cast from '%s' to '%s' */ 4254 query_message(6, type_name(tn->tn_type), type_name(tp)); 4255 4256 tn = convert(CVT, 0, tp, tn); 4257 tn->tn_cast = true; 4258 tn->tn_sys = sys; 4259 4260 return tn; 4261 4262 invalid_cast: 4263 /* invalid cast from '%s' to '%s' */ 4264 error(147, type_name(tn->tn_type), type_name(tp)); 4265 return NULL; 4266 } 4267 4268 void 4269 add_function_argument(function_call *call, tnode_t *arg) 4270 { 4271 /* 4272 * If there was a serious error in the expression for the argument, 4273 * create a dummy argument so the positions of the remaining arguments 4274 * will not change. 4275 */ 4276 if (arg == NULL) 4277 arg = build_integer_constant(INT, 0); 4278 4279 if (call->args_len >= call->args_cap) { 4280 call->args_cap += 8; 4281 tnode_t **new_args = expr_zero_alloc( 4282 call->args_cap * sizeof(*call->args), "tnode*[]"); 4283 if (call->args_len > 0) 4284 memcpy(new_args, call->args, 4285 call->args_len * sizeof(*call->args)); 4286 call->args = new_args; 4287 } 4288 call->args[call->args_len++] = arg; 4289 } 4290 4291 /* 4292 * Compare the type of an argument with the corresponding type of a 4293 * prototype parameter. If it is a valid combination, but both types 4294 * are not the same, insert a conversion to convert the argument into 4295 * the type of the parameter. 4296 */ 4297 static tnode_t * 4298 check_prototype_argument( 4299 int n, /* pos of arg */ 4300 type_t *tp, /* expected type (from prototype) */ 4301 tnode_t *tn) /* argument */ 4302 { 4303 tnode_t *ln = xcalloc(1, sizeof(*ln)); 4304 ln->tn_type = expr_unqualified_type(tp); 4305 ln->tn_lvalue = true; 4306 if (typeok(FARG, n, ln, tn)) { 4307 bool dowarn; 4308 if (!types_compatible(tp, tn->tn_type, 4309 true, false, (dowarn = false, &dowarn)) || dowarn) 4310 tn = convert(FARG, n, tp, tn); 4311 } 4312 free(ln); 4313 return tn; 4314 } 4315 4316 /* 4317 * Check types of all function arguments and insert conversions, 4318 * if necessary. 4319 */ 4320 static void 4321 check_function_arguments(const function_call *call) 4322 { 4323 type_t *ftp = call->func->tn_type->t_subt; 4324 4325 /* get # of parameters in the prototype */ 4326 int npar = 0; 4327 for (const sym_t *p = ftp->u.params; p != NULL; p = p->s_next) 4328 npar++; 4329 4330 int narg = (int)call->args_len; 4331 4332 const sym_t *param = ftp->u.params; 4333 if (ftp->t_proto && npar != narg && !(ftp->t_vararg && npar < narg)) { 4334 /* argument mismatch: %d %s passed, %d expected */ 4335 error(150, narg, narg != 1 ? "arguments" : "argument", npar); 4336 param = NULL; 4337 } 4338 4339 for (int i = 0; i < narg; i++) { 4340 tnode_t *arg = call->args[i]; 4341 4342 /* some things which are always not allowed */ 4343 tspec_t at = arg->tn_type->t_tspec; 4344 if (at == VOID) { 4345 /* void expressions may not be arguments, arg #%d */ 4346 error(151, i + 1); 4347 return; 4348 } 4349 if (is_struct_or_union(at) && is_incomplete(arg->tn_type)) { 4350 /* argument cannot have unknown size, arg #%d */ 4351 error(152, i + 1); 4352 return; 4353 } 4354 if (is_integer(at) && 4355 arg->tn_type->t_is_enum && 4356 is_incomplete(arg->tn_type)) { 4357 /* argument cannot have unknown size, arg #%d */ 4358 warning(152, i + 1); 4359 } 4360 4361 arg = cconv(arg); 4362 call->args[i] = arg; 4363 4364 arg = param != NULL 4365 ? check_prototype_argument(i + 1, param->s_type, arg) 4366 : promote(NOOP, true, arg); 4367 call->args[i] = arg; 4368 4369 if (param != NULL) 4370 param = param->s_next; 4371 } 4372 } 4373 4374 tnode_t * 4375 build_function_call(tnode_t *func, bool sys, function_call *call) 4376 { 4377 4378 if (func == NULL) 4379 return NULL; 4380 4381 call->func = func; 4382 check_ctype_function_call(call); 4383 4384 func = cconv(func); 4385 call->func = func; 4386 4387 if (func->tn_type->t_tspec != PTR || 4388 func->tn_type->t_subt->t_tspec != FUNC) { 4389 /* cannot call '%s', must be a function */ 4390 error(149, type_name(func->tn_type)); 4391 return NULL; 4392 } 4393 4394 check_function_arguments(call); 4395 4396 tnode_t *ntn = expr_alloc_tnode(); 4397 ntn->tn_op = CALL; 4398 ntn->tn_type = func->tn_type->t_subt->t_subt; 4399 ntn->tn_sys = sys; 4400 ntn->u.call = call; 4401 return ntn; 4402 } 4403 4404 /* 4405 * Return the value of an integral constant expression. 4406 * If the expression is not constant or its type is not an integer 4407 * type, an error message is printed. 4408 */ 4409 val_t * 4410 integer_constant(tnode_t *tn, bool required) 4411 { 4412 4413 if (tn != NULL) 4414 tn = cconv(tn); 4415 if (tn != NULL) 4416 tn = promote(NOOP, false, tn); 4417 4418 val_t *v = xcalloc(1, sizeof(*v)); 4419 4420 if (tn == NULL) { 4421 lint_assert(seen_error); 4422 debug_step("constant node is null; returning 1 instead"); 4423 v->v_tspec = INT; 4424 v->u.integer = 1; 4425 return v; 4426 } 4427 4428 v->v_tspec = tn->tn_type->t_tspec; 4429 4430 if (tn->tn_op == CON) { 4431 lint_assert(tn->tn_type->t_tspec == tn->u.value.v_tspec); 4432 if (is_integer(tn->u.value.v_tspec)) { 4433 v->v_unsigned_since_c90 = 4434 tn->u.value.v_unsigned_since_c90; 4435 v->u.integer = tn->u.value.u.integer; 4436 return v; 4437 } 4438 v->u.integer = (int64_t)tn->u.value.u.floating; 4439 } else 4440 v->u.integer = 1; 4441 4442 if (required) 4443 /* integral constant expression expected */ 4444 error(55); 4445 else 4446 /* variable array dimension is a C99/GCC extension */ 4447 c99ism(318); 4448 4449 if (!is_integer(v->v_tspec)) 4450 v->v_tspec = INT; 4451 4452 return v; 4453 } 4454 4455 static bool 4456 is_constcond_false(const tnode_t *tn, tspec_t t) 4457 { 4458 return (t == BOOL || t == INT) && 4459 tn->tn_op == CON && tn->u.value.u.integer == 0; 4460 } 4461 4462 /* 4463 * Perform some tests on expressions which can't be done in build_binary() 4464 * and functions called by build_binary(). These tests must be done here 4465 * because we need some information about the context in which the operations 4466 * are performed. 4467 * After all tests are performed and dofreeblk is true, expr() frees the 4468 * memory which is used for the expression. 4469 */ 4470 void 4471 expr(tnode_t *tn, bool vctx, bool cond, bool dofreeblk, bool is_do_while) 4472 { 4473 4474 if (tn == NULL) { /* in case of errors */ 4475 expr_free_all(); 4476 return; 4477 } 4478 4479 /* expr() is also called in global initializations */ 4480 if (dcs->d_kind != DLK_EXTERN && !is_do_while) 4481 check_statement_reachable(); 4482 4483 check_expr_misc(tn, vctx, cond, !cond, false, false, false); 4484 if (tn->tn_op == ASSIGN && !tn->tn_parenthesized) { 4485 if (hflag && cond) 4486 /* assignment in conditional context */ 4487 warning(159); 4488 } else if (tn->tn_op == CON) { 4489 if (hflag && cond && !suppress_constcond && 4490 !tn->tn_system_dependent && 4491 !(is_do_while && 4492 is_constcond_false(tn, tn->tn_type->t_tspec))) 4493 /* constant in conditional context */ 4494 warning(161); 4495 } 4496 if (!modtab[tn->tn_op].m_has_side_effect) { 4497 /* 4498 * for left operands of COMMA this warning is already printed 4499 */ 4500 if (tn->tn_op != COMMA && !vctx && !cond) 4501 check_null_effect(tn); 4502 } 4503 debug_node(tn); 4504 4505 if (dofreeblk) 4506 expr_free_all(); 4507 } 4508 4509 /* If the expression has the form '*(arr + idx)', check the array index. */ 4510 static void 4511 check_array_index(const tnode_t *indir, bool taking_address) 4512 { 4513 const tnode_t *plus, *arr, *idx; 4514 4515 if (indir->tn_op == INDIR 4516 && (plus = indir->u.ops.left, plus->tn_op == PLUS) 4517 && plus->u.ops.left->tn_op == ADDR 4518 && (arr = plus->u.ops.left->u.ops.left, true) 4519 && (arr->tn_op == STRING || arr->tn_op == NAME) 4520 && arr->tn_type->t_tspec == ARRAY 4521 && (idx = plus->u.ops.right, idx->tn_op == CON) 4522 && (!is_incomplete(arr->tn_type) || idx->u.value.u.integer < 0)) 4523 goto proceed; 4524 return; 4525 4526 proceed:; 4527 int elsz = length_in_bits(arr->tn_type->t_subt, NULL); 4528 if (elsz == 0) 4529 return; 4530 elsz /= CHAR_SIZE; 4531 4532 /* Change the unit of the index from bytes to element size. */ 4533 int64_t con = is_uinteger(idx->tn_type->t_tspec) 4534 ? (int64_t)((uint64_t)idx->u.value.u.integer / elsz) 4535 : idx->u.value.u.integer / elsz; 4536 4537 int dim = arr->tn_type->u.dimension + (taking_address ? 1 : 0); 4538 4539 if (!is_uinteger(idx->tn_type->t_tspec) && con < 0) 4540 /* array subscript %jd cannot be negative */ 4541 warning(167, (intmax_t)con); 4542 else if (dim > 0 && (uint64_t)con >= (uint64_t)dim) 4543 /* array subscript %ju cannot be > %d */ 4544 warning(168, (uintmax_t)con, dim - 1); 4545 } 4546 4547 static void 4548 check_expr_addr(const tnode_t *ln, bool szof, bool fcall) 4549 { 4550 /* XXX: Taking warn_about_unreachable into account here feels wrong. */ 4551 if (ln->tn_op == NAME && (reached || !warn_about_unreachable)) { 4552 if (!szof) 4553 mark_as_set(ln->u.sym); 4554 mark_as_used(ln->u.sym, fcall, szof); 4555 } 4556 check_array_index(ln, true); 4557 } 4558 4559 /* 4560 * If there is an asm statement in one of the compound statements around, 4561 * there may be other side effects, so don't warn. 4562 */ 4563 static bool 4564 is_asm_around(void) 4565 { 4566 for (decl_level *dl = dcs; dl != NULL; dl = dl->d_enclosing) 4567 if (dl->d_asm) 4568 return true; 4569 return false; 4570 } 4571 4572 static void 4573 check_expr_side_effect(const tnode_t *ln, bool szof) 4574 { 4575 4576 /* XXX: Taking warn_about_unreachable into account here feels wrong. */ 4577 if (ln->tn_op == NAME && (reached || !warn_about_unreachable)) { 4578 scl_t sc = ln->u.sym->s_scl; 4579 if (sc != EXTERN && sc != STATIC && 4580 !ln->u.sym->s_set && !szof && !is_asm_around()) { 4581 /* '%s' may be used before set */ 4582 warning(158, ln->u.sym->s_name); 4583 mark_as_set(ln->u.sym); 4584 } 4585 mark_as_used(ln->u.sym, false, false); 4586 } 4587 } 4588 4589 static void 4590 check_expr_assign(const tnode_t *ln, bool szof) 4591 { 4592 /* XXX: Taking warn_about_unreachable into account here feels wrong. */ 4593 if (ln->tn_op == NAME && !szof && (reached || !warn_about_unreachable)) { 4594 mark_as_set(ln->u.sym); 4595 if (ln->u.sym->s_scl == EXTERN) 4596 outusg(ln->u.sym); 4597 } 4598 check_array_index(ln, false); 4599 } 4600 4601 static void 4602 check_expr_call(const tnode_t *tn, const tnode_t *ln, 4603 bool szof, bool vctx, bool cond, bool retval_discarded) 4604 { 4605 lint_assert(ln->tn_op == ADDR); 4606 lint_assert(ln->u.ops.left->tn_op == NAME); 4607 if (!szof && !is_compiler_builtin(ln->u.ops.left->u.sym->s_name)) 4608 outcall(tn, vctx || cond, retval_discarded); 4609 4610 const function_call *call = tn->u.call; 4611 if (call->args_len == 4 || call->args_len == 5) 4612 check_snprintb(call); 4613 } 4614 4615 static void 4616 check_expr_op(op_t op, const tnode_t *ln, bool szof, bool fcall, bool eqwarn) 4617 { 4618 switch (op) { 4619 case ADDR: 4620 check_expr_addr(ln, szof, fcall); 4621 break; 4622 case LOAD: 4623 check_array_index(ln, false); 4624 /* FALLTHROUGH */ 4625 case INCBEF: 4626 case DECBEF: 4627 case INCAFT: 4628 case DECAFT: 4629 case ADDASS: 4630 case SUBASS: 4631 case MULASS: 4632 case DIVASS: 4633 case MODASS: 4634 case ANDASS: 4635 case ORASS: 4636 case XORASS: 4637 case SHLASS: 4638 case SHRASS: 4639 case REAL: 4640 case IMAG: 4641 check_expr_side_effect(ln, szof); 4642 break; 4643 case ASSIGN: 4644 check_expr_assign(ln, szof); 4645 break; 4646 case EQ: 4647 if (hflag && eqwarn) 4648 /* operator '==' found where '=' was expected */ 4649 warning(160); 4650 break; 4651 default: 4652 break; 4653 } 4654 } 4655 4656 /* 4657 * vctx ??? 4658 * cond whether the expression is a condition that 4659 * will be compared with 0 4660 * eqwarn whether the operator '==' might be a 4661 * misspelled '=' 4662 * fcall whether the expression is a function call 4663 * retval_discarded whether the return value of a function call 4664 * is discarded; such calls will be analyzed by 4665 * lint2 in messages 4, 8 and 9 4666 * szof whether the expression is part of a sizeof 4667 * expression, which means that its value is 4668 * discarded since only the type is relevant 4669 */ 4670 void 4671 check_expr_misc(const tnode_t *tn, bool vctx, bool cond, 4672 bool eqwarn, bool fcall, bool retval_discarded, bool szof) 4673 { 4674 4675 if (tn == NULL) 4676 return; 4677 op_t op = tn->tn_op; 4678 if (op == NAME || op == CON || op == STRING) 4679 return; 4680 bool is_direct = op == CALL 4681 && tn->u.call->func->tn_op == ADDR 4682 && tn->u.call->func->u.ops.left->tn_op == NAME; 4683 if (op == CALL) { 4684 const function_call *call = tn->u.call; 4685 if (is_direct) 4686 check_expr_call(tn, call->func, 4687 szof, vctx, cond, retval_discarded); 4688 bool discard = op == CVT && tn->tn_type->t_tspec == VOID; 4689 check_expr_misc(call->func, false, false, false, is_direct, 4690 discard, szof); 4691 for (size_t i = 0, n = call->args_len; i < n; i++) 4692 check_expr_misc(call->args[i], 4693 true, false, false, false, false, szof); 4694 return; 4695 } 4696 4697 lint_assert(has_operands(tn)); 4698 tnode_t *ln = tn->u.ops.left; 4699 tnode_t *rn = tn->u.ops.right; 4700 check_expr_op(op, ln, szof, fcall, eqwarn); 4701 4702 const mod_t *mp = &modtab[op]; 4703 bool cvctx = mp->m_value_context; 4704 bool ccond = mp->m_compares_with_zero; 4705 bool eq = mp->m_warn_if_operand_eq && 4706 !ln->tn_parenthesized && 4707 rn != NULL && !rn->tn_parenthesized; 4708 4709 /* 4710 * Values of operands of ':' are not used if the type of at least 4711 * one of the operands (for GCC compatibility) is 'void'. 4712 * 4713 * XXX test/value context of QUEST should probably be used as 4714 * context for both operands of COLON. 4715 */ 4716 if (op == COLON && tn->tn_type->t_tspec == VOID) 4717 cvctx = ccond = false; 4718 bool discard = op == CVT && tn->tn_type->t_tspec == VOID; 4719 check_expr_misc(ln, cvctx, ccond, eq, is_direct, discard, szof); 4720 4721 switch (op) { 4722 case LOGAND: 4723 case LOGOR: 4724 check_expr_misc(rn, false, true, eq, false, false, szof); 4725 break; 4726 case COLON: 4727 check_expr_misc(rn, cvctx, ccond, eq, false, false, szof); 4728 break; 4729 case COMMA: 4730 check_expr_misc(rn, vctx, cond, false, false, false, szof); 4731 break; 4732 default: 4733 if (mp->m_binary) 4734 check_expr_misc(rn, true, false, eq, false, false, 4735 szof); 4736 break; 4737 } 4738 } 4739 4740 /* 4741 * Return whether the expression can be used for static initialization. 4742 * 4743 * Constant initialization expressions must be constant or an address 4744 * of a static object with an optional offset. In the first case, 4745 * the result is returned in *offsp. In the second case, the static 4746 * object is returned in *symp and the offset in *offsp. 4747 * 4748 * The expression can consist of PLUS, MINUS, ADDR, NAME, STRING and 4749 * CON. Type conversions are allowed if they do not change binary 4750 * representation (including width). 4751 * 4752 * C99 6.6 "Constant expressions" 4753 * C99 6.7.8p4 restricts initializers for static storage duration 4754 */ 4755 bool 4756 constant_addr(const tnode_t *tn, const sym_t **symp, ptrdiff_t *offsp) 4757 { 4758 const sym_t *sym; 4759 ptrdiff_t offs1, offs2; 4760 tspec_t t, ot; 4761 4762 switch (tn->tn_op) { 4763 case MINUS: 4764 if (tn->u.ops.right->tn_op == CVT) 4765 return constant_addr(tn->u.ops.right, symp, offsp); 4766 else if (tn->u.ops.right->tn_op != CON) 4767 return false; 4768 /* FALLTHROUGH */ 4769 case PLUS: 4770 offs1 = offs2 = 0; 4771 if (tn->u.ops.left->tn_op == CON) { 4772 offs1 = (ptrdiff_t)tn->u.ops.left->u.value.u.integer; 4773 if (!constant_addr(tn->u.ops.right, &sym, &offs2)) 4774 return false; 4775 } else if (tn->u.ops.right->tn_op == CON) { 4776 offs2 = (ptrdiff_t)tn->u.ops.right->u.value.u.integer; 4777 if (tn->tn_op == MINUS) 4778 offs2 = -offs2; 4779 if (!constant_addr(tn->u.ops.left, &sym, &offs1)) 4780 return false; 4781 } else { 4782 return false; 4783 } 4784 *symp = sym; 4785 *offsp = offs1 + offs2; 4786 return true; 4787 case ADDR: 4788 if (tn->u.ops.left->tn_op == NAME) { 4789 *symp = tn->u.ops.left->u.sym; 4790 *offsp = 0; 4791 return true; 4792 } else { 4793 /* 4794 * If this were the front end of a compiler, we would 4795 * return a label instead of 0, at least if 4796 * 'tn->u.ops.left->tn_op == STRING'. 4797 */ 4798 *symp = NULL; 4799 *offsp = 0; 4800 return true; 4801 } 4802 case CVT: 4803 t = tn->tn_type->t_tspec; 4804 ot = tn->u.ops.left->tn_type->t_tspec; 4805 if ((!is_integer(t) && t != PTR) || 4806 (!is_integer(ot) && ot != PTR)) { 4807 return false; 4808 } 4809 #if 0 4810 /*- 4811 * consider: 4812 * struct foo { 4813 * unsigned char a; 4814 * } f = { 4815 * (unsigned char)(unsigned long) 4816 * (&(((struct foo *)0)->a)) 4817 * }; 4818 * since psize(unsigned long) != psize(unsigned char), 4819 * this fails. 4820 */ 4821 else if (psize(t) != psize(ot)) 4822 return -1; 4823 #endif 4824 return constant_addr(tn->u.ops.left, symp, offsp); 4825 default: 4826 return false; 4827 } 4828 } 4829 4830 /* Append s2 to s1, then free s2. */ 4831 buffer * 4832 cat_strings(buffer *s1, buffer *s2) 4833 { 4834 4835 if ((s1->data != NULL) != (s2->data != NULL)) { 4836 /* cannot concatenate wide and regular string literals */ 4837 error(292); 4838 return s1; 4839 } 4840 4841 if (s1->data != NULL) { 4842 while (s1->len + s2->len + 1 > s1->cap) 4843 s1->cap *= 2; 4844 s1->data = xrealloc(s1->data, s1->cap); 4845 memcpy(s1->data + s1->len, s2->data, s2->len + 1); 4846 free(s2->data); 4847 } 4848 s1->len += s2->len; 4849 free(s2); 4850 4851 return s1; 4852 } 4853 4854 4855 typedef struct stmt_expr { 4856 memory_pool se_mem; 4857 sym_t *se_sym; 4858 struct stmt_expr *se_enclosing; 4859 } stmt_expr; 4860 4861 static stmt_expr *stmt_exprs; 4862 4863 void 4864 begin_statement_expr(void) 4865 { 4866 debug_enter(); 4867 4868 stmt_expr *se = xmalloc(sizeof(*se)); 4869 se->se_mem = expr_save_memory(); 4870 se->se_sym = NULL; 4871 se->se_enclosing = stmt_exprs; 4872 stmt_exprs = se; 4873 } 4874 4875 void 4876 do_statement_expr(tnode_t *tn) 4877 { 4878 block_level--; 4879 mem_block_level--; 4880 stmt_exprs->se_sym = tn != NULL 4881 ? mktempsym(block_dup_type(tn->tn_type)) 4882 : NULL; /* after a syntax error */ 4883 mem_block_level++; 4884 block_level++; 4885 /* '({ ... })' is a GCC extension */ 4886 gnuism(320); 4887 } 4888 4889 tnode_t * 4890 end_statement_expr(void) 4891 { 4892 tnode_t *tn; 4893 4894 stmt_expr *se = stmt_exprs; 4895 if (se->se_sym == NULL) { 4896 tn = NULL; /* after a syntax error */ 4897 goto end; 4898 } 4899 4900 tn = build_name(se->se_sym, false); 4901 (void)expr_save_memory(); /* leak */ 4902 expr_restore_memory(se->se_mem); 4903 stmt_exprs = se->se_enclosing; 4904 free(se); 4905 4906 end: 4907 debug_leave(); 4908 return tn; 4909 } 4910 4911 bool 4912 in_statement_expr(void) 4913 { 4914 return stmt_exprs != NULL; 4915 } 4916
Indexes created Fri Oct 03 17:10:05 GMT 2025