tree.c revision 1.654
1 /* $NetBSD: tree.c,v 1.654 2024/10/10 05:01:03 rillig Exp $ */ 2 3 /* 4 * Copyright (c) 1994, 1995 Jochen Pohl 5 * All Rights Reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. All advertising materials mentioning features or use of this software 16 * must display the following acknowledgement: 17 * This product includes software developed by Jochen Pohl for 18 * The NetBSD Project. 19 * 4. The name of the author may not be used to endorse or promote products 20 * derived from this software without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 23 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 24 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 25 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 26 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 27 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 28 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 29 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 30 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 31 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 32 */ 33 34 #if HAVE_NBTOOL_CONFIG_H 35 #include "nbtool_config.h" 36 #endif 37 38 #include <sys/cdefs.h> 39 #if defined(__RCSID) 40 __RCSID("$NetBSD: tree.c,v 1.654 2024/10/10 05:01:03 rillig Exp $"); 41 #endif 42 43 #include <float.h> 44 #include <limits.h> 45 #include <math.h> 46 #include <signal.h> 47 #include <stdlib.h> 48 #include <string.h> 49 50 #include "lint1.h" 51 52 53 typedef struct integer_constraints { 54 int64_t smin; /* signed minimum */ 55 int64_t smax; /* signed maximum */ 56 uint64_t umin; /* unsigned minimum */ 57 uint64_t umax; /* unsigned maximum */ 58 uint64_t bclr; /* bits that are definitely clear */ 59 } integer_constraints; 60 61 62 static uint64_t 63 u64_fill_right(uint64_t x) 64 { 65 x |= x >> 1; 66 x |= x >> 2; 67 x |= x >> 4; 68 x |= x >> 8; 69 x |= x >> 16; 70 x |= x >> 32; 71 return x; 72 } 73 74 static bool 75 str_ends_with(const char *haystack, const char *needle) 76 { 77 size_t hlen = strlen(haystack); 78 size_t nlen = strlen(needle); 79 80 return nlen <= hlen && 81 memcmp(haystack + hlen - nlen, needle, nlen) == 0; 82 } 83 84 static unsigned 85 width_in_bits(const type_t *tp) 86 { 87 88 lint_assert(is_integer(tp->t_tspec)); 89 return tp->t_bitfield 90 ? tp->t_bit_field_width 91 : size_in_bits(tp->t_tspec); 92 } 93 94 static int 95 portable_rank_cmp(tspec_t t1, tspec_t t2) 96 { 97 const ttab_t *p1 = type_properties(t1), *p2 = type_properties(t2); 98 lint_assert(p1->tt_rank_kind == p2->tt_rank_kind); 99 lint_assert(p1->tt_rank_value > 0); 100 lint_assert(p2->tt_rank_value > 0); 101 return (int)p1->tt_rank_value - (int)p2->tt_rank_value; 102 } 103 104 static bool 105 ic_maybe_signed(const type_t *tp, const integer_constraints *ic) 106 { 107 return !is_uinteger(tp->t_tspec) && ic->bclr >> 63 == 0; 108 } 109 110 static integer_constraints 111 ic_any(const type_t *tp) 112 { 113 integer_constraints c; 114 115 uint64_t vbits = value_bits(width_in_bits(tp)); 116 if (is_uinteger(tp->t_tspec)) { 117 c.smin = INT64_MIN; 118 c.smax = INT64_MAX; 119 c.umin = 0; 120 c.umax = vbits; 121 c.bclr = ~c.umax; 122 } else { 123 c.smin = (int64_t)-1 - (int64_t)(vbits >> 1); 124 c.smax = (int64_t)(vbits >> 1); 125 c.umin = 0; 126 c.umax = UINT64_MAX; 127 c.bclr = 0; 128 } 129 return c; 130 } 131 132 static integer_constraints 133 ic_con(const type_t *tp, const val_t *v) 134 { 135 integer_constraints c; 136 137 lint_assert(is_integer(tp->t_tspec)); 138 int64_t si = v->u.integer; 139 uint64_t ui = (uint64_t)si; 140 c.smin = si; 141 c.smax = si; 142 c.umin = ui; 143 c.umax = ui; 144 c.bclr = ~ui; 145 return c; 146 } 147 148 static integer_constraints 149 ic_cvt(const type_t *ntp, const type_t *otp, integer_constraints a) 150 { 151 unsigned nw = width_in_bits(ntp); 152 unsigned ow = width_in_bits(otp); 153 bool nu = is_uinteger(ntp->t_tspec); 154 bool ou = is_uinteger(otp->t_tspec); 155 156 if (nw >= ow && nu == ou) 157 return a; 158 if (nw > ow && ou) 159 return a; 160 return ic_any(ntp); 161 } 162 163 static integer_constraints 164 ic_mult(const type_t *tp, integer_constraints a, integer_constraints b) 165 { 166 integer_constraints c; 167 168 if (ic_maybe_signed(tp, &a) || ic_maybe_signed(tp, &b) 169 || (a.umax > 0 && b.umax > ic_any(tp).umax / a.umax)) 170 return ic_any(tp); 171 172 c.smin = INT64_MIN; 173 c.smax = INT64_MAX; 174 c.umin = a.umin * b.umin; 175 c.umax = a.umax * b.umax; 176 c.bclr = ~u64_fill_right(c.umax); 177 return c; 178 } 179 180 static integer_constraints 181 ic_bitand(integer_constraints a, integer_constraints b) 182 { 183 integer_constraints c; 184 185 c.smin = INT64_MIN; 186 c.smax = INT64_MAX; 187 c.umin = 0; 188 c.umax = ~(a.bclr | b.bclr); 189 c.bclr = a.bclr | b.bclr; 190 return c; 191 } 192 193 static integer_constraints 194 ic_bitor(integer_constraints a, integer_constraints b) 195 { 196 integer_constraints c; 197 198 c.smin = INT64_MIN; 199 c.smax = INT64_MAX; 200 c.umin = 0; 201 c.umax = ~(a.bclr & b.bclr); 202 c.bclr = a.bclr & b.bclr; 203 return c; 204 } 205 206 static integer_constraints 207 ic_mod(const type_t *tp, integer_constraints a, integer_constraints b) 208 { 209 integer_constraints c; 210 211 if (ic_maybe_signed(tp, &a) || ic_maybe_signed(tp, &b)) 212 return ic_any(tp); 213 214 c.smin = INT64_MIN; 215 c.smax = INT64_MAX; 216 c.umin = 0; 217 c.umax = b.umax - 1; 218 c.bclr = ~u64_fill_right(c.umax); 219 return c; 220 } 221 222 static integer_constraints 223 ic_div(const type_t *tp, integer_constraints a, integer_constraints b) 224 { 225 integer_constraints c; 226 227 if (ic_maybe_signed(tp, &a) || ic_maybe_signed(tp, &b) || b.umin == 0) 228 return ic_any(tp); 229 230 c.smin = INT64_MIN; 231 c.smax = INT64_MAX; 232 c.umin = a.umin / b.umax; 233 c.umax = a.umax / b.umin; 234 c.bclr = ~u64_fill_right(c.umax); 235 return c; 236 } 237 238 static integer_constraints 239 ic_shl(const type_t *tp, integer_constraints a, integer_constraints b) 240 { 241 integer_constraints c; 242 unsigned int amount; 243 244 if (ic_maybe_signed(tp, &a)) 245 return ic_any(tp); 246 247 if (b.smin == b.smax && b.smin >= 0 && b.smin < 64) 248 amount = (unsigned int)b.smin; 249 else if (b.umin == b.umax && b.umin < 64) 250 amount = (unsigned int)b.umin; 251 else 252 return ic_any(tp); 253 254 c.smin = INT64_MIN; 255 c.smax = INT64_MAX; 256 c.umin = 0; 257 c.umax = UINT64_MAX; 258 c.bclr = a.bclr << amount | (((uint64_t)1 << amount) - 1); 259 return c; 260 } 261 262 static integer_constraints 263 ic_shr(const type_t *tp, integer_constraints a, integer_constraints b) 264 { 265 integer_constraints c; 266 unsigned int amount; 267 268 if (ic_maybe_signed(tp, &a)) 269 return ic_any(tp); 270 271 if (b.smin == b.smax && b.smin >= 0 && b.smin < 64) 272 amount = (unsigned int)b.smin; 273 else if (b.umin == b.umax && b.umin < 64) 274 amount = (unsigned int)b.umin; 275 else 276 return ic_any(tp); 277 278 c.smin = INT64_MIN; 279 c.smax = INT64_MAX; 280 c.umin = 0; 281 c.umax = UINT64_MAX; 282 c.bclr = a.bclr >> amount | ~(~(uint64_t)0 >> amount); 283 return c; 284 } 285 286 static integer_constraints 287 ic_cond(integer_constraints a, integer_constraints b) 288 { 289 integer_constraints c; 290 291 c.smin = a.smin < b.smin ? a.smin : b.smin; 292 c.smax = a.smax > b.smax ? a.smax : b.smax; 293 c.umin = a.umin < b.umin ? a.umin : b.umin; 294 c.umax = a.umax > b.umax ? a.umax : b.umax; 295 c.bclr = a.bclr & b.bclr; 296 return c; 297 } 298 299 static integer_constraints 300 ic_expr(const tnode_t *tn) 301 { 302 integer_constraints lc, rc; 303 304 lint_assert(is_integer(tn->tn_type->t_tspec)); 305 306 switch (tn->tn_op) { 307 case CON: 308 return ic_con(tn->tn_type, &tn->u.value); 309 case CVT: 310 if (!is_integer(tn->u.ops.left->tn_type->t_tspec)) 311 return ic_any(tn->tn_type); 312 lc = ic_expr(tn->u.ops.left); 313 return ic_cvt(tn->tn_type, tn->u.ops.left->tn_type, lc); 314 case MULT: 315 lc = ic_expr(before_conversion(tn->u.ops.left)); 316 rc = ic_expr(before_conversion(tn->u.ops.right)); 317 return ic_mult(tn->tn_type, lc, rc); 318 case DIV: 319 lc = ic_expr(before_conversion(tn->u.ops.left)); 320 rc = ic_expr(before_conversion(tn->u.ops.right)); 321 return ic_div(tn->tn_type, lc, rc); 322 case MOD: 323 lc = ic_expr(before_conversion(tn->u.ops.left)); 324 rc = ic_expr(before_conversion(tn->u.ops.right)); 325 return ic_mod(tn->tn_type, lc, rc); 326 case SHL: 327 lc = ic_expr(tn->u.ops.left); 328 rc = ic_expr(tn->u.ops.right); 329 return ic_shl(tn->tn_type, lc, rc); 330 case SHR: 331 lc = ic_expr(tn->u.ops.left); 332 rc = ic_expr(tn->u.ops.right); 333 return ic_shr(tn->tn_type, lc, rc); 334 case BITAND: 335 lc = ic_expr(tn->u.ops.left); 336 rc = ic_expr(tn->u.ops.right); 337 return ic_bitand(lc, rc); 338 case BITOR: 339 lc = ic_expr(tn->u.ops.left); 340 rc = ic_expr(tn->u.ops.right); 341 return ic_bitor(lc, rc); 342 case QUEST: 343 lc = ic_expr(tn->u.ops.right->u.ops.left); 344 rc = ic_expr(tn->u.ops.right->u.ops.right); 345 return ic_cond(lc, rc); 346 default: 347 return ic_any(tn->tn_type); 348 } 349 } 350 351 uint64_t 352 possible_bits(const tnode_t *tn) 353 { 354 return ~ic_expr(tn).bclr; 355 } 356 357 bool 358 attributes_contain(const attribute_list *attrs, const char *str) 359 { 360 for (size_t i = 0, n = attrs->len; i < n; i++) { 361 const attribute *attr = attrs->attrs + i; 362 if (attr->prefix == NULL && strcmp(attr->name, str) == 0) 363 return true; 364 } 365 return false; 366 } 367 368 /* Build 'pointer to tp', 'array of tp' or 'function returning tp'. */ 369 type_t * 370 block_derive_type(type_t *tp, tspec_t t) 371 { 372 373 type_t *tp2 = block_zero_alloc(sizeof(*tp2), "type"); 374 tp2->t_tspec = t; 375 tp2->t_subt = tp; 376 return tp2; 377 } 378 379 /* 380 * Derive 'pointer to tp' or 'function returning tp'. 381 * The memory is freed at the end of the current expression. 382 */ 383 type_t * 384 expr_derive_type(type_t *tp, tspec_t t) 385 { 386 387 type_t *tp2 = expr_zero_alloc(sizeof(*tp2), "type"); 388 tp2->t_tspec = t; 389 tp2->t_subt = tp; 390 return tp2; 391 } 392 393 /* Create an expression from a unary or binary operator and its operands. */ 394 static tnode_t * 395 build_op(op_t op, bool sys, type_t *type, tnode_t *ln, tnode_t *rn) 396 { 397 398 tnode_t *ntn = expr_alloc_tnode(); 399 ntn->tn_op = op; 400 ntn->tn_type = type; 401 ntn->tn_sys = sys; 402 ntn->u.ops.left = ln; 403 ntn->u.ops.right = rn; 404 405 if (op == INDIR || op == FSEL) { 406 lint_assert(ln->tn_type->t_tspec == PTR); 407 tspec_t t = ln->tn_type->t_subt->t_tspec; 408 ntn->tn_lvalue = t != FUNC && t != VOID; 409 } 410 411 return ntn; 412 } 413 414 tnode_t * 415 build_constant(type_t *tp, val_t *v) 416 { 417 418 tnode_t *n = expr_alloc_tnode(); 419 n->tn_op = CON; 420 n->tn_type = tp; 421 n->u.value = *v; 422 n->u.value.v_tspec = tp->t_tspec; 423 free(v); 424 return n; 425 } 426 427 static tnode_t * 428 build_integer_constant(tspec_t t, int64_t si) 429 { 430 431 tnode_t *n = expr_alloc_tnode(); 432 n->tn_op = CON; 433 n->tn_type = gettyp(t); 434 n->u.value.v_tspec = t; 435 n->u.value.v_unsigned_since_c90 = false; 436 n->u.value.v_char_constant = false; 437 n->u.value.u.integer = si; 438 return n; 439 } 440 441 static void 442 fallback_symbol(sym_t *sym) 443 { 444 445 if (Tflag && fallback_symbol_strict_bool(sym)) 446 return; 447 448 if (funcsym != NULL && (strcmp(sym->s_name, "__FUNCTION__") == 0 || 449 strcmp(sym->s_name, "__PRETTY_FUNCTION__") == 0)) { 450 /* __FUNCTION__/__PRETTY_FUNCTION__ is a GCC extension */ 451 gnuism(316); 452 goto return_function_name; 453 } 454 455 if (funcsym != NULL && strcmp(sym->s_name, "__func__") == 0) { 456 if (!allow_c99) 457 /* __func__ is a C99 feature */ 458 warning(317); 459 /* C11 6.4.2.2 */ 460 return_function_name: 461 sym->s_type = block_derive_type(gettyp(CHAR), ARRAY); 462 sym->s_type->t_const = true; 463 sym->s_type->u.dimension = (int)strlen(funcsym->s_name) + 1; 464 return; 465 } 466 467 /* '%s' undefined */ 468 error(99, sym->s_name); 469 } 470 471 /* 472 * Functions that are predeclared by GCC or other compilers can be called 473 * with arbitrary arguments. Since lint usually runs after a successful 474 * compilation, it's the compiler's job to catch any errors. 475 */ 476 bool 477 is_compiler_builtin(const char *name) 478 { 479 /* https://gcc.gnu.org/onlinedocs/gcc/C-Extensions.html */ 480 if (allow_gcc) { 481 if (strncmp(name, "__atomic_", 9) == 0 || 482 strncmp(name, "__builtin_", 10) == 0 || 483 strcmp(name, "alloca") == 0 || 484 /* obsolete but still in use, as of 2021 */ 485 strncmp(name, "__sync_", 7) == 0) 486 return true; 487 } 488 489 /* https://software.intel.com/sites/landingpage/IntrinsicsGuide/ */ 490 if (strncmp(name, "_mm_", 4) == 0) 491 return true; 492 493 return false; 494 } 495 496 /* https://gcc.gnu.org/onlinedocs/gcc/Integer-Overflow-Builtins.html */ 497 static bool 498 is_gcc_bool_builtin(const char *name) 499 { 500 return strncmp(name, "__builtin_", 10) == 0 && 501 (str_ends_with(name, "_overflow") || 502 str_ends_with(name, "_overflow_p")); 503 } 504 505 static void 506 build_name_call(sym_t *sym) 507 { 508 509 if (is_compiler_builtin(sym->s_name)) { 510 /* 511 * Do not warn about these, just assume that they are regular 512 * functions compatible with non-prototype calling conventions. 513 */ 514 if (allow_gcc && is_gcc_bool_builtin(sym->s_name)) 515 sym->s_type = gettyp(BOOL); 516 } else if (allow_c99) 517 /* function '%s' implicitly declared to return int */ 518 error(215, sym->s_name); 519 else if (!allow_trad) 520 /* function '%s' implicitly declared to return int */ 521 warning(215, sym->s_name); 522 523 /* XXX if !allow_c90, the symbol should be exported to level 0 */ 524 sym->s_type = block_derive_type(sym->s_type, FUNC); 525 } 526 527 /* Create a node for a name (symbol table entry). */ 528 tnode_t * 529 build_name(sym_t *sym, bool is_funcname) 530 { 531 532 if (sym->s_scl == NO_SCL && !in_gcc_attribute) { 533 sym->s_scl = EXTERN; 534 sym->s_def = DECL; 535 if (is_funcname) 536 build_name_call(sym); 537 else 538 fallback_symbol(sym); 539 } 540 541 lint_assert(sym->s_kind == SK_VCFT || sym->s_kind == SK_MEMBER); 542 543 tnode_t *n = expr_alloc_tnode(); 544 n->tn_type = sym->s_type; 545 if (sym->s_scl == BOOL_CONST) { 546 n->tn_op = CON; 547 n->u.value.v_tspec = BOOL; 548 n->u.value.v_unsigned_since_c90 = false; 549 n->u.value.v_char_constant = false; 550 n->u.value.u.integer = sym->u.s_bool_constant ? 1 : 0; 551 } else if (sym->s_scl == ENUM_CONST) { 552 n->tn_op = CON; 553 n->u.value.v_tspec = INT; /* ENUM is in n->tn_type */ 554 n->u.value.v_unsigned_since_c90 = false; 555 n->u.value.v_char_constant = false; 556 n->u.value.u.integer = sym->u.s_enum_constant; 557 } else { 558 n->tn_op = NAME; 559 n->u.sym = sym; 560 if (sym->s_kind == SK_VCFT && sym->s_type->t_tspec != FUNC) 561 n->tn_lvalue = true; 562 } 563 564 return n; 565 } 566 567 tnode_t * 568 build_string(buffer *lit) 569 { 570 size_t value_len = lit->len; 571 if (lit->data != NULL) { 572 quoted_iterator it = { .end = 0 }; 573 for (value_len = 0; quoted_next(lit, &it); value_len++) 574 continue; 575 } 576 577 type_t *tp = expr_zero_alloc(sizeof(*tp), "type"); 578 tp->t_tspec = ARRAY; 579 tp->t_subt = gettyp(lit->data != NULL ? CHAR : WCHAR_TSPEC); 580 tp->u.dimension = (int)(value_len + 1); 581 582 tnode_t *n = expr_alloc_tnode(); 583 n->tn_op = STRING; 584 n->tn_type = tp; 585 n->tn_lvalue = true; 586 587 n->u.str_literals = expr_zero_alloc(sizeof(*n->u.str_literals), "tnode.string"); 588 n->u.str_literals->len = lit->len; 589 590 if (lit->data != NULL) { 591 n->u.str_literals->data = expr_zero_alloc(lit->len + 1, 592 "tnode.string.data"); 593 (void)memcpy(n->u.str_literals->data, lit->data, lit->len + 1); 594 free(lit->data); 595 } 596 free(lit); 597 598 return n; 599 } 600 601 tnode_t * 602 build_generic_selection(const tnode_t *expr, 603 struct generic_association *sel) 604 { 605 tnode_t *default_result = NULL; 606 607 for (; sel != NULL; sel = sel->ga_prev) { 608 if (expr != NULL && 609 types_compatible(sel->ga_arg, expr->tn_type, 610 false, false, NULL)) 611 return sel->ga_result; 612 else if (sel->ga_arg == NULL) 613 default_result = sel->ga_result; 614 } 615 return default_result; 616 } 617 618 static bool 619 is_out_of_char_range(const tnode_t *tn) 620 { 621 return tn->tn_op == CON && 622 !tn->u.value.v_char_constant && 623 !(0 <= tn->u.value.u.integer && 624 tn->u.value.u.integer < 1 << (CHAR_SIZE - 1)); 625 } 626 627 static bool 628 check_nonportable_char_comparison(op_t op, 629 const tnode_t *ln, tspec_t lt, 630 const tnode_t *rn, tspec_t rt) 631 { 632 if (!(hflag || pflag)) 633 return true; 634 635 if (lt == CHAR && is_out_of_char_range(rn)) { 636 char buf[128]; 637 (void)snprintf(buf, sizeof(buf), "%s %d", 638 op_name(op), (int)rn->u.value.u.integer); 639 /* nonportable character comparison '%s' */ 640 warning(230, buf); 641 return false; 642 } 643 if (rt == CHAR && is_out_of_char_range(ln)) { 644 char buf[128]; 645 (void)snprintf(buf, sizeof(buf), "%d %s ?", 646 (int)ln->u.value.u.integer, op_name(op)); 647 /* nonportable character comparison '%s' */ 648 warning(230, buf); 649 return false; 650 } 651 return true; 652 } 653 654 static void 655 check_integer_comparison(op_t op, tnode_t *ln, tnode_t *rn) 656 { 657 658 tspec_t lt = ln->tn_type->t_tspec; 659 tspec_t rt = rn->tn_type->t_tspec; 660 661 if (ln->tn_op != CON && rn->tn_op != CON) 662 return; 663 664 if (!is_integer(lt) || !is_integer(rt)) 665 return; 666 667 if (any_query_enabled && !in_system_header) { 668 if (lt == CHAR && rn->tn_op == CON && 669 !rn->u.value.v_char_constant) { 670 /* comparison '%s' of 'char' with plain integer %d */ 671 query_message(14, 672 op_name(op), (int)rn->u.value.u.integer); 673 } 674 if (rt == CHAR && ln->tn_op == CON && 675 !ln->u.value.v_char_constant) { 676 /* comparison '%s' of 'char' with plain integer %d */ 677 query_message(14, 678 op_name(op), (int)ln->u.value.u.integer); 679 } 680 } 681 682 if (!check_nonportable_char_comparison(op, ln, lt, rn, rt)) 683 return; 684 685 if (is_uinteger(lt) && !is_uinteger(rt) && 686 rn->tn_op == CON && rn->u.value.u.integer <= 0) { 687 if (rn->u.value.u.integer < 0) { 688 /* operator '%s' compares '%s' with '%s' */ 689 warning(162, op_name(op), 690 type_name(ln->tn_type), "negative constant"); 691 } else if (op == LT || op == GE) 692 /* operator '%s' compares '%s' with '%s' */ 693 warning(162, op_name(op), type_name(ln->tn_type), "0"); 694 return; 695 } 696 if (is_uinteger(rt) && !is_uinteger(lt) && 697 ln->tn_op == CON && ln->u.value.u.integer <= 0) { 698 if (ln->u.value.u.integer < 0) { 699 /* operator '%s' compares '%s' with '%s' */ 700 warning(162, op_name(op), 701 "negative constant", type_name(rn->tn_type)); 702 } else if (op == GT || op == LE) 703 /* operator '%s' compares '%s' with '%s' */ 704 warning(162, op_name(op), "0", type_name(rn->tn_type)); 705 return; 706 } 707 } 708 709 static const tspec_t arith_rank[] = { 710 LDOUBLE, DOUBLE, FLOAT, 711 #ifdef INT128_SIZE 712 UINT128, INT128, 713 #endif 714 ULLONG, LLONG, 715 ULONG, LONG, 716 UINT, INT, 717 }; 718 719 /* Keep unsigned in traditional C */ 720 static tspec_t 721 usual_arithmetic_conversion_trad(tspec_t lt, tspec_t rt) 722 { 723 724 size_t i; 725 for (i = 0; arith_rank[i] != INT; i++) 726 if (lt == arith_rank[i] || rt == arith_rank[i]) 727 break; 728 729 tspec_t t = arith_rank[i]; 730 if (is_uinteger(lt) || is_uinteger(rt)) 731 if (is_integer(t) && !is_uinteger(t)) 732 return unsigned_type(t); 733 return t; 734 } 735 736 static tspec_t 737 usual_arithmetic_conversion_c90(tspec_t lt, tspec_t rt) 738 { 739 740 if (lt == rt) 741 return lt; 742 743 if (lt == LCOMPLEX || rt == LCOMPLEX) 744 return LCOMPLEX; 745 if (lt == DCOMPLEX || rt == DCOMPLEX) 746 return DCOMPLEX; 747 if (lt == FCOMPLEX || rt == FCOMPLEX) 748 return FCOMPLEX; 749 if (lt == LDOUBLE || rt == LDOUBLE) 750 return LDOUBLE; 751 if (lt == DOUBLE || rt == DOUBLE) 752 return DOUBLE; 753 if (lt == FLOAT || rt == FLOAT) 754 return FLOAT; 755 756 if (size_in_bits(lt) > size_in_bits(rt)) 757 return lt; 758 if (size_in_bits(lt) < size_in_bits(rt)) 759 return rt; 760 761 size_t i; 762 for (i = 3; arith_rank[i] != INT; i++) 763 if (arith_rank[i] == lt || arith_rank[i] == rt) 764 break; 765 if ((is_uinteger(lt) || is_uinteger(rt)) && 766 !is_uinteger(arith_rank[i])) 767 i--; 768 return arith_rank[i]; 769 } 770 771 static tnode_t * 772 apply_usual_arithmetic_conversions(op_t op, tnode_t *tn, tspec_t t) 773 { 774 type_t *ntp = expr_dup_type(tn->tn_type); 775 ntp->t_tspec = t; 776 if (tn->tn_op != CON) { 777 /* usual arithmetic conversion for '%s' from '%s' to '%s' */ 778 query_message(4, op_name(op), 779 type_name(tn->tn_type), type_name(ntp)); 780 } 781 return convert(op, 0, ntp, tn); 782 } 783 784 /* 785 * Apply the "usual arithmetic conversions" (C99 6.3.1.8), which gives both 786 * operands the same type. 787 */ 788 static void 789 balance(op_t op, tnode_t **lnp, tnode_t **rnp) 790 { 791 792 tspec_t lt = (*lnp)->tn_type->t_tspec; 793 tspec_t rt = (*rnp)->tn_type->t_tspec; 794 if (!is_arithmetic(lt) || !is_arithmetic(rt)) 795 return; 796 797 tspec_t t = allow_c90 798 ? usual_arithmetic_conversion_c90(lt, rt) 799 : usual_arithmetic_conversion_trad(lt, rt); 800 801 if (modtab[op].m_comparison 802 && is_integer(lt) && (*lnp)->tn_op != CON 803 && is_floating(t) && (*rnp)->tn_op == CON) 804 /* comparing integer '%s' to floating point constant %Lg */ 805 warning(379, type_name((*lnp)->tn_type), 806 (*rnp)->u.value.u.floating); 807 808 if (t != lt) 809 *lnp = apply_usual_arithmetic_conversions(op, *lnp, t); 810 if (t != rt) 811 *rnp = apply_usual_arithmetic_conversions(op, *rnp, t); 812 813 if (is_integer(t)) { 814 unsigned lw = width_in_bits((*lnp)->tn_type); 815 unsigned rw = width_in_bits((*rnp)->tn_type); 816 if (lw < rw) 817 *lnp = convert(NOOP, 0, (*rnp)->tn_type, *lnp); 818 if (rw < lw) 819 *rnp = convert(NOOP, 0, (*lnp)->tn_type, *rnp); 820 } 821 } 822 823 static tnode_t * 824 build_address(bool sys, tnode_t *tn, bool force) 825 { 826 tspec_t t; 827 828 if (!force && ((t = tn->tn_type->t_tspec) == ARRAY || t == FUNC)) { 829 if (!allow_c90) 830 /* '&' before array or function: ignored */ 831 warning(127); 832 return tn; 833 } 834 835 /* eliminate '&*' */ 836 if (tn->tn_op == INDIR && 837 tn->u.ops.left->tn_type->t_tspec == PTR && 838 tn->u.ops.left->tn_type->t_subt == tn->tn_type) { 839 return tn->u.ops.left; 840 } 841 842 return build_op(ADDR, sys, expr_derive_type(tn->tn_type, PTR), 843 tn, NULL); 844 } 845 846 static uint64_t 847 fold_unsigned_integer(op_t op, uint64_t l, uint64_t r, 848 uint64_t max_value, bool *overflow) 849 { 850 switch (op) { 851 case COMPL: 852 return ~l & max_value; 853 case UPLUS: 854 return +l; 855 case UMINUS: 856 return -l & max_value; 857 case MULT: 858 *overflow = r > 0 && l > max_value / r; 859 return l * r; 860 case DIV: 861 if (r == 0) { 862 /* division by 0 */ 863 error(139); 864 return max_value; 865 } 866 return l / r; 867 case MOD: 868 if (r == 0) { 869 /* modulus by 0 */ 870 error(140); 871 return 0; 872 } 873 return l % r; 874 case PLUS: 875 *overflow = l > max_value - r; 876 return l + r; 877 case MINUS: 878 *overflow = l < r; 879 return l - r; 880 case SHL: 881 /* TODO: warn about out-of-bounds 'r'. */ 882 /* TODO: warn about overflow. */ 883 return l << (r & 63); 884 case SHR: 885 /* TODO: warn about out-of-bounds 'r'. */ 886 return l >> (r & 63); 887 case LT: 888 return l < r ? 1 : 0; 889 case LE: 890 return l <= r ? 1 : 0; 891 case GT: 892 return l > r ? 1 : 0; 893 case GE: 894 return l >= r ? 1 : 0; 895 case EQ: 896 return l == r ? 1 : 0; 897 case NE: 898 return l != r ? 1 : 0; 899 case BITAND: 900 return l & r; 901 case BITXOR: 902 return l ^ r; 903 case BITOR: 904 return l | r; 905 default: 906 lint_assert(/*CONSTCOND*/false); 907 /* NOTREACHED */ 908 } 909 } 910 911 static int64_t 912 fold_signed_integer(op_t op, int64_t l, int64_t r, 913 int64_t min_value, int64_t max_value, bool *overflow) 914 { 915 switch (op) { 916 case COMPL: 917 return ~l; 918 case UPLUS: 919 return +l; 920 case UMINUS: 921 *overflow = l == min_value; 922 return *overflow ? l : -l; 923 case MULT:; 924 uint64_t al = l >= 0 ? (uint64_t)l : -(uint64_t)l; 925 uint64_t ar = r >= 0 ? (uint64_t)r : -(uint64_t)r; 926 bool neg = (l >= 0) != (r >= 0); 927 uint64_t max_prod = (uint64_t)max_value + (neg ? 1 : 0); 928 if (al > 0 && ar > max_prod / al) { 929 *overflow = true; 930 return neg ? min_value : max_value; 931 } 932 return l * r; 933 case DIV: 934 if (r == 0) { 935 /* division by 0 */ 936 error(139); 937 return max_value; 938 } 939 if (l == min_value && r == -1) { 940 *overflow = true; 941 return l; 942 } 943 return l / r; 944 case MOD: 945 if (r == 0) { 946 /* modulus by 0 */ 947 error(140); 948 return 0; 949 } 950 if (l == min_value && r == -1) { 951 *overflow = true; 952 return 0; 953 } 954 return l % r; 955 case PLUS: 956 if (r > 0 && l > max_value - r) { 957 *overflow = true; 958 return max_value; 959 } 960 if (r < 0 && l < min_value - r) { 961 *overflow = true; 962 return min_value; 963 } 964 return l + r; 965 case MINUS: 966 if (r > 0 && l < min_value + r) { 967 *overflow = true; 968 return min_value; 969 } 970 if (r < 0 && l > max_value + r) { 971 *overflow = true; 972 return max_value; 973 } 974 return l - r; 975 case SHL: 976 /* TODO: warn about out-of-bounds 'r'. */ 977 /* TODO: warn about overflow. */ 978 return l << (r & 63); 979 case SHR: 980 /* TODO: warn about out-of-bounds 'r'. */ 981 if (l < 0) 982 return (int64_t)~(~(uint64_t)l >> (r & 63)); 983 return (int64_t)((uint64_t)l >> (r & 63)); 984 case LT: 985 return l < r ? 1 : 0; 986 case LE: 987 return l <= r ? 1 : 0; 988 case GT: 989 return l > r ? 1 : 0; 990 case GE: 991 return l >= r ? 1 : 0; 992 case EQ: 993 return l == r ? 1 : 0; 994 case NE: 995 return l != r ? 1 : 0; 996 case BITAND: 997 return l & r; 998 case BITXOR: 999 return l ^ r; 1000 case BITOR: 1001 return l | r; 1002 default: 1003 lint_assert(/*CONSTCOND*/false); 1004 /* NOTREACHED */ 1005 } 1006 } 1007 1008 static tnode_t * 1009 fold_constant_integer(tnode_t *tn) 1010 { 1011 1012 lint_assert(has_operands(tn)); 1013 tspec_t t = tn->u.ops.left->tn_type->t_tspec; 1014 int64_t l = tn->u.ops.left->u.value.u.integer; 1015 int64_t r = is_binary(tn) ? tn->u.ops.right->u.value.u.integer : 0; 1016 uint64_t mask = value_bits(size_in_bits(t)); 1017 1018 int64_t res; 1019 bool overflow = false; 1020 if (!is_integer(t) || is_uinteger(t)) { 1021 uint64_t u_res = fold_unsigned_integer(tn->tn_op, 1022 (uint64_t)l, (uint64_t)r, mask, &overflow); 1023 if (u_res > mask) 1024 overflow = true; 1025 res = (int64_t)u_res; 1026 if (overflow && hflag) { 1027 char buf[128]; 1028 if (is_binary(tn)) { 1029 snprintf(buf, sizeof(buf), "%ju %s %ju", 1030 (uintmax_t)l, op_name(tn->tn_op), 1031 (uintmax_t)r); 1032 } else { 1033 snprintf(buf, sizeof(buf), "%s%ju", 1034 op_name(tn->tn_op), (uintmax_t)l); 1035 } 1036 /* '%s' overflows '%s' */ 1037 warning(141, buf, type_name(tn->tn_type)); 1038 } 1039 } else { 1040 int64_t max_value = (int64_t)(mask >> 1); 1041 int64_t min_value = -max_value - 1; 1042 res = fold_signed_integer(tn->tn_op, 1043 l, r, min_value, max_value, &overflow); 1044 if (res < min_value || res > max_value) 1045 overflow = true; 1046 if (overflow && hflag) { 1047 char buf[128]; 1048 if (is_binary(tn)) { 1049 snprintf(buf, sizeof(buf), "%jd %s %jd", 1050 (intmax_t)l, op_name(tn->tn_op), 1051 (intmax_t)r); 1052 } else if (tn->tn_op == UMINUS && l < 0) { 1053 snprintf(buf, sizeof(buf), "-(%jd)", 1054 (intmax_t)l); 1055 } else { 1056 snprintf(buf, sizeof(buf), "%s%jd", 1057 op_name(tn->tn_op), (intmax_t)l); 1058 } 1059 /* '%s' overflows '%s' */ 1060 warning(141, buf, type_name(tn->tn_type)); 1061 } 1062 } 1063 1064 val_t *v = xcalloc(1, sizeof(*v)); 1065 v->v_tspec = tn->tn_type->t_tspec; 1066 v->u.integer = convert_integer(res, t, size_in_bits(t)); 1067 1068 tnode_t *cn = build_constant(tn->tn_type, v); 1069 if (tn->u.ops.left->tn_system_dependent) 1070 cn->tn_system_dependent = true; 1071 if (is_binary(tn) && tn->u.ops.right->tn_system_dependent) 1072 cn->tn_system_dependent = true; 1073 1074 return cn; 1075 } 1076 1077 static tnode_t * 1078 build_struct_access(op_t op, bool sys, tnode_t *ln, tnode_t *rn) 1079 { 1080 1081 lint_assert(rn->tn_op == NAME); 1082 lint_assert(is_member(rn->u.sym)); 1083 1084 bool lvalue = op == ARROW || ln->tn_lvalue; 1085 1086 if (op == POINT) 1087 ln = build_address(sys, ln, true); 1088 else if (ln->tn_type->t_tspec != PTR) { 1089 lint_assert(!allow_c90); 1090 lint_assert(is_integer(ln->tn_type->t_tspec)); 1091 ln = convert(NOOP, 0, expr_derive_type(gettyp(VOID), PTR), ln); 1092 } 1093 1094 tnode_t *ctn = build_integer_constant(PTRDIFF_TSPEC, 1095 rn->u.sym->u.s_member.sm_offset_in_bits / CHAR_SIZE); 1096 1097 type_t *ptr_tp = expr_derive_type(rn->tn_type, PTR); 1098 tnode_t *ntn = build_op(PLUS, sys, ptr_tp, ln, ctn); 1099 if (ln->tn_op == CON) 1100 ntn = fold_constant_integer(ntn); 1101 1102 op_t nop = rn->tn_type->t_bitfield ? FSEL : INDIR; 1103 ntn = build_op(nop, sys, ntn->tn_type->t_subt, ntn, NULL); 1104 if (!lvalue) 1105 ntn->tn_lvalue = false; 1106 1107 return ntn; 1108 } 1109 1110 /* 1111 * Get the size in bytes of type tp->t_subt, as a constant expression of type 1112 * ptrdiff_t as seen from the target platform. 1113 */ 1114 static tnode_t * 1115 subt_size_in_bytes(type_t *tp) 1116 { 1117 1118 lint_assert(tp->t_tspec == PTR); 1119 tp = tp->t_subt; 1120 1121 int elem = 1; 1122 while (tp->t_tspec == ARRAY) { 1123 elem *= tp->u.dimension; 1124 tp = tp->t_subt; 1125 } 1126 1127 int elsz_in_bits = 0; 1128 switch (tp->t_tspec) { 1129 case FUNC: 1130 /* pointer to function is not allowed here */ 1131 error(110); 1132 break; 1133 case VOID: 1134 /* cannot do pointer arithmetic on operand of unknown size */ 1135 gnuism(136); 1136 break; 1137 case STRUCT: 1138 case UNION: 1139 if ((elsz_in_bits = (int)tp->u.sou->sou_size_in_bits) == 0) 1140 /* cannot do pointer arithmetic on operand of ... */ 1141 error(136); 1142 break; 1143 case ENUM: 1144 if (is_incomplete(tp)) 1145 /* cannot do pointer arithmetic on operand of ... */ 1146 warning(136); 1147 /* FALLTHROUGH */ 1148 default: 1149 if ((elsz_in_bits = size_in_bits(tp->t_tspec)) == 0) 1150 /* cannot do pointer arithmetic on operand of ... */ 1151 error(136); 1152 else 1153 lint_assert(elsz_in_bits != -1); 1154 break; 1155 } 1156 1157 if (elem == 0 && elsz_in_bits != 0) 1158 /* cannot do pointer arithmetic on operand of unknown size */ 1159 error(136); 1160 1161 if (elsz_in_bits == 0) 1162 elsz_in_bits = CHAR_SIZE; 1163 1164 return build_integer_constant(PTRDIFF_TSPEC, 1165 (int64_t)(elem * elsz_in_bits / CHAR_SIZE)); 1166 } 1167 1168 static tnode_t * 1169 build_prepost_incdec(op_t op, bool sys, tnode_t *ln) 1170 { 1171 1172 lint_assert(ln != NULL); 1173 tnode_t *cn = ln->tn_type->t_tspec == PTR 1174 ? subt_size_in_bytes(ln->tn_type) 1175 : build_integer_constant(INT, 1); 1176 return build_op(op, sys, ln->tn_type, ln, cn); 1177 } 1178 1179 static void 1180 check_enum_array_index(const tnode_t *ln, const tnode_t *rn) 1181 { 1182 1183 if (ln->tn_op != ADDR || ln->u.ops.left->tn_op != NAME) 1184 return; 1185 1186 const type_t *ltp = ln->u.ops.left->tn_type; 1187 if (ltp->t_tspec != ARRAY || ltp->t_incomplete_array) 1188 return; 1189 1190 if (rn->tn_op != CVT || !rn->tn_type->t_is_enum) 1191 return; 1192 if (rn->u.ops.left->tn_op != LOAD) 1193 return; 1194 1195 const type_t *rtp = rn->u.ops.left->tn_type; 1196 const sym_t *ec = rtp->u.enumer->en_first_enumerator; 1197 const sym_t *max_ec = ec; 1198 lint_assert(ec != NULL); 1199 for (ec = ec->s_next; ec != NULL; ec = ec->s_next) 1200 if (ec->u.s_enum_constant > max_ec->u.s_enum_constant) 1201 max_ec = ec; 1202 1203 int64_t max_enum_value = max_ec->u.s_enum_constant; 1204 lint_assert(INT_MIN <= max_enum_value && max_enum_value <= INT_MAX); 1205 1206 int max_array_index = ltp->u.dimension - 1; 1207 if (max_enum_value == max_array_index) 1208 return; 1209 1210 if (max_enum_value == max_array_index + 1 && 1211 (strstr(max_ec->s_name, "MAX") != NULL || 1212 strstr(max_ec->s_name, "max") != NULL || 1213 strstr(max_ec->s_name, "NUM") != NULL || 1214 strstr(max_ec->s_name, "num") != NULL)) 1215 return; 1216 1217 /* maximum value %d of '%s' does not match maximum array index %d */ 1218 warning(348, (int)max_enum_value, type_name(rtp), max_array_index); 1219 print_previous_declaration(max_ec); 1220 } 1221 1222 static tnode_t * 1223 build_plus_minus(op_t op, bool sys, tnode_t *ln, tnode_t *rn) 1224 { 1225 1226 if (rn->tn_type->t_tspec == PTR && is_integer(ln->tn_type->t_tspec)) { 1227 tnode_t *tmp = ln; 1228 ln = rn; 1229 rn = tmp; 1230 /* pointer addition has integer on the left-hand side */ 1231 query_message(5); 1232 } 1233 1234 /* pointer +- integer */ 1235 tspec_t lt = ln->tn_type->t_tspec; 1236 tspec_t rt = rn->tn_type->t_tspec; 1237 if (lt == PTR && rt != PTR) { 1238 lint_assert(is_integer(rt)); 1239 1240 check_ctype_macro_invocation(ln, rn); 1241 check_enum_array_index(ln, rn); 1242 1243 tnode_t *elsz = subt_size_in_bytes(ln->tn_type); 1244 tspec_t szt = elsz->tn_type->t_tspec; 1245 if (rt != szt && rt != unsigned_type(szt)) 1246 rn = convert(NOOP, 0, elsz->tn_type, rn); 1247 1248 tnode_t *prod = build_op(MULT, sys, rn->tn_type, rn, elsz); 1249 if (rn->tn_op == CON) 1250 prod = fold_constant_integer(prod); 1251 1252 return build_op(op, sys, ln->tn_type, ln, prod); 1253 } 1254 1255 /* pointer - pointer */ 1256 if (rt == PTR) { 1257 lint_assert(lt == PTR); 1258 lint_assert(op == MINUS); 1259 1260 type_t *ptrdiff = gettyp(PTRDIFF_TSPEC); 1261 tnode_t *raw_diff = build_op(op, sys, ptrdiff, ln, rn); 1262 if (ln->tn_op == CON && rn->tn_op == CON) 1263 raw_diff = fold_constant_integer(raw_diff); 1264 1265 tnode_t *elsz = subt_size_in_bytes(ln->tn_type); 1266 balance(NOOP, &raw_diff, &elsz); 1267 1268 return build_op(DIV, sys, ptrdiff, raw_diff, elsz); 1269 } 1270 1271 return build_op(op, sys, ln->tn_type, ln, rn); 1272 } 1273 1274 static tnode_t * 1275 build_bit_shift(op_t op, bool sys, tnode_t *ln, tnode_t *rn) 1276 { 1277 1278 if (!allow_c90 && rn->tn_type->t_tspec != INT) 1279 // XXX: C1978 7.5 says: "Both [operators] perform the usual 1280 // arithmetic conversions on their operands." 1281 // TODO: Add a test to exercise this part of the code. 1282 rn = convert(NOOP, 0, gettyp(INT), rn); 1283 return build_op(op, sys, ln->tn_type, ln, rn); 1284 } 1285 1286 static bool 1287 is_null_pointer(const tnode_t *tn) 1288 { 1289 tspec_t t = tn->tn_type->t_tspec; 1290 1291 // TODO: Investigate how other pointers are stored, in particular, 1292 // whether a pointer constant can have a non-zero value. 1293 // If not, simplify the code below. 1294 return ((t == PTR && tn->tn_type->t_subt->t_tspec == VOID) 1295 || is_integer(t)) 1296 && (tn->tn_op == CON && tn->u.value.u.integer == 0); 1297 } 1298 1299 /* Return a type based on tp1, with added qualifiers from tp2. */ 1300 static type_t * 1301 merge_qualifiers(type_t *tp1, const type_t *tp2) 1302 { 1303 1304 lint_assert(tp1->t_tspec == PTR); 1305 lint_assert(tp2->t_tspec == PTR); 1306 1307 bool c1 = tp1->t_subt->t_const; 1308 bool c2 = tp2->t_subt->t_const; 1309 bool v1 = tp1->t_subt->t_volatile; 1310 bool v2 = tp2->t_subt->t_volatile; 1311 1312 if (c1 == (c1 | c2) && v1 == (v1 | v2)) 1313 return tp1; 1314 1315 type_t *nstp = expr_dup_type(tp1->t_subt); 1316 nstp->t_const |= c2; 1317 nstp->t_volatile |= v2; 1318 1319 type_t *ntp = expr_dup_type(tp1); 1320 ntp->t_subt = nstp; 1321 return ntp; 1322 } 1323 1324 /* See C99 6.5.15 "Conditional operator". */ 1325 static tnode_t * 1326 build_colon(bool sys, tnode_t *ln, tnode_t *rn) 1327 { 1328 tspec_t lt = ln->tn_type->t_tspec; 1329 tspec_t rt = rn->tn_type->t_tspec; 1330 1331 type_t *tp; 1332 if (is_arithmetic(lt) && is_arithmetic(rt)) 1333 /* The operands were already balanced in build_binary. */ 1334 tp = ln->tn_type; 1335 else if (lt == BOOL && rt == BOOL) 1336 tp = ln->tn_type; 1337 else if (lt == VOID || rt == VOID) 1338 tp = gettyp(VOID); 1339 else if (is_struct_or_union(lt)) { 1340 lint_assert(is_struct_or_union(rt)); 1341 lint_assert(ln->tn_type->u.sou == rn->tn_type->u.sou); 1342 if (is_incomplete(ln->tn_type)) { 1343 /* unknown operand size, op '%s' */ 1344 error(138, op_name(COLON)); 1345 return NULL; 1346 } 1347 tp = ln->tn_type; 1348 } else if (lt == PTR && is_integer(rt)) { 1349 if (rt != PTRDIFF_TSPEC) 1350 rn = convert(NOOP, 0, gettyp(PTRDIFF_TSPEC), rn); 1351 tp = ln->tn_type; 1352 } else if (rt == PTR && is_integer(lt)) { 1353 if (lt != PTRDIFF_TSPEC) 1354 ln = convert(NOOP, 0, gettyp(PTRDIFF_TSPEC), ln); 1355 tp = rn->tn_type; 1356 } else if (lt == PTR && is_null_pointer(rn)) 1357 tp = merge_qualifiers(ln->tn_type, rn->tn_type); 1358 else if (rt == PTR && is_null_pointer(ln)) 1359 tp = merge_qualifiers(rn->tn_type, ln->tn_type); 1360 else if (lt == PTR && ln->tn_type->t_subt->t_tspec == VOID) 1361 tp = merge_qualifiers(ln->tn_type, rn->tn_type); 1362 else if (rt == PTR && rn->tn_type->t_subt->t_tspec == VOID) 1363 tp = merge_qualifiers(rn->tn_type, ln->tn_type); 1364 else { 1365 /* 1366 * XXX For now we simply take the left type. This is probably 1367 * wrong, if one type contains a function prototype and the 1368 * other one, at the same place, only an old-style declaration. 1369 */ 1370 tp = merge_qualifiers(ln->tn_type, rn->tn_type); 1371 } 1372 1373 return build_op(COLON, sys, tp, ln, rn); 1374 } 1375 1376 /* TODO: check for varargs */ 1377 static bool 1378 is_cast_redundant(const tnode_t *tn) 1379 { 1380 const type_t *ntp = tn->tn_type, *otp = tn->u.ops.left->tn_type; 1381 tspec_t nt = ntp->t_tspec, ot = otp->t_tspec; 1382 1383 if (nt == BOOL || ot == BOOL) 1384 return nt == BOOL && ot == BOOL; 1385 1386 if (is_integer(nt) && is_integer(ot)) { 1387 unsigned int nw = width_in_bits(ntp), ow = width_in_bits(otp); 1388 if (is_uinteger(nt) == is_uinteger(ot)) 1389 return nw >= ow; 1390 return is_uinteger(ot) && nw > ow; 1391 } 1392 1393 if (is_complex(nt) || is_complex(ot)) 1394 return is_complex(nt) && is_complex(ot) && 1395 size_in_bits(nt) >= size_in_bits(ot); 1396 1397 if (is_floating(nt) && is_floating(ot)) 1398 return size_in_bits(nt) >= size_in_bits(ot); 1399 1400 if (nt == PTR && ot == PTR) { 1401 if (!ntp->t_subt->t_const && otp->t_subt->t_const) 1402 return false; 1403 if (!ntp->t_subt->t_volatile && otp->t_subt->t_volatile) 1404 return false; 1405 1406 if (ntp->t_subt->t_tspec == VOID || 1407 otp->t_subt->t_tspec == VOID || 1408 types_compatible(ntp->t_subt, otp->t_subt, 1409 false, false, NULL)) 1410 return true; 1411 } 1412 1413 return false; 1414 } 1415 1416 static bool 1417 is_assignment(op_t op) 1418 { 1419 1420 return op == ASSIGN || 1421 op == MULASS || 1422 op == DIVASS || 1423 op == MODASS || 1424 op == ADDASS || 1425 op == SUBASS || 1426 op == SHLASS || 1427 op == SHRASS || 1428 op == ANDASS || 1429 op == XORASS || 1430 op == ORASS || 1431 op == RETURN || 1432 op == INIT; 1433 } 1434 1435 static tnode_t * 1436 build_assignment(op_t op, bool sys, tnode_t *ln, tnode_t *rn) 1437 { 1438 1439 tspec_t lt = ln->tn_type->t_tspec; 1440 tspec_t rt = rn->tn_type->t_tspec; 1441 1442 if (any_query_enabled && is_assignment(rn->tn_op)) { 1443 /* chained assignment with '%s' and '%s' */ 1444 query_message(10, op_name(op), op_name(rn->tn_op)); 1445 } 1446 1447 if ((op == ADDASS || op == SUBASS) && lt == PTR) { 1448 lint_assert(is_integer(rt)); 1449 tnode_t *ctn = subt_size_in_bytes(ln->tn_type); 1450 if (rn->tn_type->t_tspec != ctn->tn_type->t_tspec) 1451 rn = convert(NOOP, 0, ctn->tn_type, rn); 1452 rn = build_op(MULT, sys, rn->tn_type, rn, ctn); 1453 if (rn->u.ops.left->tn_op == CON) 1454 rn = fold_constant_integer(rn); 1455 } 1456 1457 if ((op == ASSIGN || op == RETURN || op == INIT) && 1458 (lt == STRUCT || rt == STRUCT)) { 1459 lint_assert(lt == rt); 1460 lint_assert(ln->tn_type->u.sou == rn->tn_type->u.sou); 1461 if (is_incomplete(ln->tn_type)) { 1462 if (op == RETURN) 1463 /* cannot return incomplete type */ 1464 error(212); 1465 else 1466 /* unknown operand size, op '%s' */ 1467 error(138, op_name(op)); 1468 return NULL; 1469 } 1470 } 1471 1472 if (op == SHLASS && hflag && allow_trad && allow_c90 1473 && portable_rank_cmp(lt, rt) < 0) 1474 /* semantics of '%s' change in C90; ... */ 1475 warning(118, "<<="); 1476 1477 if (op != SHLASS && op != SHRASS 1478 && (op == ASSIGN || lt != PTR) 1479 && (lt != rt || (ln->tn_type->t_bitfield && rn->tn_op == CON))) { 1480 rn = convert(op, 0, ln->tn_type, rn); 1481 rt = lt; 1482 } 1483 1484 if (is_query_enabled[20] 1485 && lt == PTR && ln->tn_type->t_subt->t_tspec != VOID 1486 && rt == PTR && rn->tn_type->t_subt->t_tspec == VOID 1487 && !is_null_pointer(rn)) 1488 /* implicit narrowing conversion from void ... */ 1489 query_message(20, type_name(ln->tn_type)); 1490 1491 if (any_query_enabled && rn->tn_op == CVT && rn->tn_cast && 1492 types_compatible(ln->tn_type, rn->tn_type, false, false, NULL) && 1493 is_cast_redundant(rn)) { 1494 /* redundant cast from '%s' to '%s' before assignment */ 1495 query_message(7, type_name(rn->u.ops.left->tn_type), 1496 type_name(rn->tn_type)); 1497 } 1498 1499 return build_op(op, sys, ln->tn_type, ln, rn); 1500 } 1501 1502 static tnode_t * 1503 build_real_imag(op_t op, bool sys, tnode_t *ln) 1504 { 1505 1506 lint_assert(ln != NULL); 1507 if (ln->tn_op == NAME) { 1508 /* 1509 * This may be too much, but it avoids wrong warnings. See 1510 * d_c99_complex_split.c. 1511 */ 1512 mark_as_used(ln->u.sym, false, false); 1513 mark_as_set(ln->u.sym); 1514 } 1515 1516 tspec_t t; 1517 switch (ln->tn_type->t_tspec) { 1518 case LCOMPLEX: 1519 t = LDOUBLE; 1520 break; 1521 case DCOMPLEX: 1522 t = DOUBLE; 1523 break; 1524 case FCOMPLEX: 1525 t = FLOAT; 1526 break; 1527 default: 1528 /* '__%s__' is illegal for type '%s' */ 1529 error(276, op == REAL ? "real" : "imag", 1530 type_name(ln->tn_type)); 1531 return NULL; 1532 } 1533 1534 tnode_t *ntn = build_op(op, sys, gettyp(t), ln, NULL); 1535 ntn->tn_lvalue = true; 1536 return ntn; 1537 } 1538 1539 static bool 1540 is_confusing_precedence(op_t op, op_t lop, bool lparen, op_t rop, bool rparen) 1541 { 1542 1543 if (op == SHL || op == SHR) { 1544 if (!lparen && (lop == PLUS || lop == MINUS)) 1545 return true; 1546 if (!rparen && (rop == PLUS || rop == MINUS)) 1547 return true; 1548 return false; 1549 } 1550 1551 if (op == LOGOR) { 1552 if (!lparen && lop == LOGAND) 1553 return true; 1554 if (!rparen && rop == LOGAND) 1555 return true; 1556 return false; 1557 } 1558 1559 lint_assert(op == BITAND || op == BITXOR || op == BITOR); 1560 if (!lparen && lop != op) { 1561 if (lop == PLUS || lop == MINUS) 1562 return true; 1563 if (lop == BITAND || lop == BITXOR) 1564 return true; 1565 } 1566 if (!rparen && rop != op) { 1567 if (rop == PLUS || rop == MINUS) 1568 return true; 1569 if (rop == BITAND || rop == BITXOR) 1570 return true; 1571 } 1572 return false; 1573 } 1574 1575 /* 1576 * Print a warning if the given node has operands which should be 1577 * parenthesized. 1578 * 1579 * XXX Does not work if an operand is a constant expression. Constant 1580 * expressions are already folded. 1581 */ 1582 static void 1583 check_precedence_confusion(tnode_t *tn) 1584 { 1585 tnode_t *ln, *rn; 1586 1587 if (!hflag) 1588 return; 1589 1590 debug_node(tn); 1591 1592 lint_assert(is_binary(tn)); 1593 for (ln = tn->u.ops.left; ln->tn_op == CVT; ln = ln->u.ops.left) 1594 continue; 1595 for (rn = tn->u.ops.right; rn->tn_op == CVT; rn = rn->u.ops.left) 1596 continue; 1597 1598 if (is_confusing_precedence(tn->tn_op, 1599 ln->tn_op, ln->tn_parenthesized, 1600 rn->tn_op, rn->tn_parenthesized)) { 1601 /* precedence confusion possible: parenthesize! */ 1602 warning(169); 1603 } 1604 } 1605 1606 static tnode_t * 1607 fold_constant_compare_zero(tnode_t *tn) 1608 { 1609 1610 val_t *v = xcalloc(1, sizeof(*v)); 1611 v->v_tspec = tn->tn_type->t_tspec; 1612 lint_assert(v->v_tspec == INT || (Tflag && v->v_tspec == BOOL)); 1613 1614 lint_assert(has_operands(tn)); 1615 bool l = constant_is_nonzero(tn->u.ops.left); 1616 bool r = is_binary(tn) && constant_is_nonzero(tn->u.ops.right); 1617 1618 switch (tn->tn_op) { 1619 case NOT: 1620 if (hflag && !suppress_constcond) 1621 /* constant operand to '!' */ 1622 warning(239); 1623 v->u.integer = !l ? 1 : 0; 1624 break; 1625 case LOGAND: 1626 v->u.integer = l && r ? 1 : 0; 1627 break; 1628 case LOGOR: 1629 v->u.integer = l || r ? 1 : 0; 1630 break; 1631 default: 1632 lint_assert(/*CONSTCOND*/false); 1633 } 1634 1635 return build_constant(tn->tn_type, v); 1636 } 1637 1638 static long double 1639 floating_error_value(tspec_t t, long double lv) 1640 { 1641 if (t == FLOAT) 1642 return lv < 0 ? -FLT_MAX : FLT_MAX; 1643 if (t == DOUBLE) 1644 return lv < 0 ? -DBL_MAX : DBL_MAX; 1645 /* 1646 * When NetBSD is cross-built in MKLINT=yes mode on x86_64 for sparc64, 1647 * tools/lint checks this code while building usr.bin/xlint. In that 1648 * situation, lint uses the preprocessor for sparc64, in which the type 1649 * 'long double' is IEEE-754-binary128, affecting the macro LDBL_MAX 1650 * below. The type 'long double', as well as the strtold 1651 * implementation, comes from the host platform x86_64 though, where 1652 * 'long double' consumes 128 bits as well but only uses 80 of them. 1653 * The exponent range of the two 'long double' types is the same, but 1654 * the maximum finite value differs due to the extended precision on 1655 * sparc64. 1656 * 1657 * To properly handle the data types of the target platform, lint would 1658 * have to implement the floating-point types in a platform-independent 1659 * way, which is not worth the effort, given how few programs 1660 * practically use 'long double'. 1661 */ 1662 /* LINTED 248: floating-point constant out of range */ 1663 long double max = LDBL_MAX; 1664 return lv < 0 ? -max : max; 1665 } 1666 1667 static bool 1668 is_floating_overflow(tspec_t t, long double val) 1669 { 1670 if (fpe != 0 || isfinite(val) == 0) 1671 return true; 1672 if (t == FLOAT && (val > FLT_MAX || val < -FLT_MAX)) 1673 return true; 1674 if (t == DOUBLE && (val > DBL_MAX || val < -DBL_MAX)) 1675 return true; 1676 return false; 1677 } 1678 1679 static tnode_t * 1680 fold_constant_floating(tnode_t *tn) 1681 { 1682 1683 fpe = 0; 1684 1685 tspec_t t = tn->tn_type->t_tspec; 1686 1687 val_t *v = xcalloc(1, sizeof(*v)); 1688 v->v_tspec = t; 1689 1690 lint_assert(is_floating(t)); 1691 lint_assert(has_operands(tn)); 1692 lint_assert(t == tn->u.ops.left->tn_type->t_tspec); 1693 lint_assert(!is_binary(tn) || t == tn->u.ops.right->tn_type->t_tspec); 1694 1695 long double lv = tn->u.ops.left->u.value.u.floating; 1696 long double rv = is_binary(tn) ? tn->u.ops.right->u.value.u.floating 1697 : 0.0; 1698 1699 switch (tn->tn_op) { 1700 case UPLUS: 1701 v->u.floating = lv; 1702 break; 1703 case UMINUS: 1704 v->u.floating = -lv; 1705 break; 1706 case MULT: 1707 v->u.floating = lv * rv; 1708 break; 1709 case DIV: 1710 if (rv == 0.0) { 1711 /* division by 0 */ 1712 error(139); 1713 v->u.floating = floating_error_value(t, lv); 1714 } else { 1715 v->u.floating = lv / rv; 1716 } 1717 break; 1718 case PLUS: 1719 v->u.floating = lv + rv; 1720 break; 1721 case MINUS: 1722 v->u.floating = lv - rv; 1723 break; 1724 case LT: 1725 v->u.integer = lv < rv ? 1 : 0; 1726 break; 1727 case LE: 1728 v->u.integer = lv <= rv ? 1 : 0; 1729 break; 1730 case GE: 1731 v->u.integer = lv >= rv ? 1 : 0; 1732 break; 1733 case GT: 1734 v->u.integer = lv > rv ? 1 : 0; 1735 break; 1736 case EQ: 1737 v->u.integer = lv == rv ? 1 : 0; 1738 break; 1739 case NE: 1740 v->u.integer = lv != rv ? 1 : 0; 1741 break; 1742 default: 1743 lint_assert(/*CONSTCOND*/false); 1744 } 1745 1746 // XXX: Must not access u.floating after setting u.integer. 1747 lint_assert(fpe != 0 || isnan(v->u.floating) == 0); 1748 if (is_complex(v->v_tspec)) { 1749 /* 1750 * Don't warn, as lint doesn't model the imaginary part of 1751 * complex numbers. 1752 */ 1753 fpe = 0; 1754 } else if (is_floating_overflow(t, v->u.floating)) { 1755 /* operator '%s' produces floating point overflow */ 1756 warning(142, op_name(tn->tn_op)); 1757 v->u.floating = floating_error_value(t, v->u.floating); 1758 fpe = 0; 1759 } 1760 1761 return build_constant(tn->tn_type, v); 1762 } 1763 1764 static void 1765 use(const tnode_t *tn) 1766 { 1767 if (tn == NULL) 1768 return; 1769 switch (tn->tn_op) { 1770 case NAME: 1771 mark_as_used(tn->u.sym, false /* XXX */, false /* XXX */); 1772 break; 1773 case CON: 1774 case STRING: 1775 break; 1776 case CALL:; 1777 const function_call *call = tn->u.call; 1778 for (size_t i = 0, n = call->args_len; i < n; i++) 1779 use(call->args[i]); 1780 break; 1781 default: 1782 lint_assert(has_operands(tn)); 1783 use(tn->u.ops.left); 1784 if (is_binary(tn)) 1785 use(tn->u.ops.right); 1786 } 1787 } 1788 1789 /* 1790 * Create a tree node for a binary operator and its two operands. Also called 1791 * for unary operators; in that case rn is NULL. 1792 * 1793 * Function calls, sizeof and casts are handled elsewhere. 1794 */ 1795 tnode_t * 1796 build_binary(tnode_t *ln, op_t op, bool sys, tnode_t *rn) 1797 { 1798 const mod_t *mp = &modtab[op]; 1799 1800 /* If there was an error in one of the operands, return. */ 1801 if (ln == NULL || (mp->m_binary && rn == NULL)) 1802 return NULL; 1803 1804 if (mp->m_value_context || mp->m_compares_with_zero) 1805 ln = cconv(ln); 1806 if (mp->m_binary && op != ARROW && op != POINT) 1807 rn = cconv(rn); 1808 1809 if (mp->m_comparison) 1810 check_integer_comparison(op, ln, rn); 1811 1812 if (mp->m_value_context || mp->m_compares_with_zero) 1813 ln = promote(op, false, ln); 1814 if (mp->m_binary && op != ARROW && op != POINT && 1815 op != ASSIGN && op != RETURN && op != INIT) 1816 rn = promote(op, false, rn); 1817 1818 if (mp->m_warn_if_left_unsigned_in_c90 && 1819 ln->tn_op == CON && ln->u.value.v_unsigned_since_c90) { 1820 /* C90 treats constant as unsigned, op '%s' */ 1821 warning(218, op_name(op)); 1822 ln->u.value.v_unsigned_since_c90 = false; 1823 } 1824 if (mp->m_warn_if_right_unsigned_in_c90 && 1825 rn->tn_op == CON && rn->u.value.v_unsigned_since_c90) { 1826 /* C90 treats constant as unsigned, op '%s' */ 1827 warning(218, op_name(op)); 1828 rn->u.value.v_unsigned_since_c90 = false; 1829 } 1830 1831 if (mp->m_balance_operands || (!allow_c90 && (op == SHL || op == SHR))) 1832 balance(op, &ln, &rn); 1833 1834 if (!typeok(op, 0, ln, rn)) 1835 return NULL; 1836 1837 tnode_t *ntn; 1838 switch (op) { 1839 case POINT: 1840 case ARROW: 1841 ntn = build_struct_access(op, sys, ln, rn); 1842 break; 1843 case NOT: 1844 if (ln->tn_op == ASSIGN && ln->u.ops.right->tn_op == CON) { 1845 /* constant assignment of type '%s' in operand ... */ 1846 warning(382, type_name(ln->tn_type), 1847 is_nonzero_val(&ln->u.ops.right->u.value) 1848 ? "true" : "false"); 1849 } 1850 ntn = build_op(op, sys, gettyp(Tflag ? BOOL : INT), ln, NULL); 1851 break; 1852 case INCAFT: 1853 case DECAFT: 1854 case INCBEF: 1855 case DECBEF: 1856 ntn = build_prepost_incdec(op, sys, ln); 1857 break; 1858 case ADDR: 1859 ntn = build_address(sys, ln, false); 1860 break; 1861 case INDIR: 1862 ntn = build_op(INDIR, sys, ln->tn_type->t_subt, ln, NULL); 1863 break; 1864 case PLUS: 1865 case MINUS: 1866 ntn = build_plus_minus(op, sys, ln, rn); 1867 break; 1868 case SHL: 1869 case SHR: 1870 ntn = build_bit_shift(op, sys, ln, rn); 1871 break; 1872 case COLON: 1873 ntn = build_colon(sys, ln, rn); 1874 break; 1875 case ASSIGN: 1876 case MULASS: 1877 case DIVASS: 1878 case MODASS: 1879 case ADDASS: 1880 case SUBASS: 1881 case SHLASS: 1882 case SHRASS: 1883 case ANDASS: 1884 case XORASS: 1885 case ORASS: 1886 case RETURN: 1887 case INIT: 1888 ntn = build_assignment(op, sys, ln, rn); 1889 break; 1890 case COMMA: 1891 if (any_query_enabled) { 1892 /* comma operator with types '%s' and '%s' */ 1893 query_message(12, 1894 type_name(ln->tn_type), type_name(rn->tn_type)); 1895 } 1896 /* FALLTHROUGH */ 1897 case QUEST: 1898 ntn = build_op(op, sys, rn->tn_type, ln, rn); 1899 break; 1900 case REAL: 1901 case IMAG: 1902 ntn = build_real_imag(op, sys, ln); 1903 break; 1904 default: 1905 lint_assert(mp->m_binary == (rn != NULL)); 1906 type_t *rettp = mp->m_returns_bool 1907 ? gettyp(Tflag ? BOOL : INT) : ln->tn_type; 1908 ntn = build_op(op, sys, rettp, ln, rn); 1909 break; 1910 } 1911 1912 if (ntn == NULL) 1913 return NULL; 1914 1915 if (mp->m_possible_precedence_confusion) 1916 check_precedence_confusion(ntn); 1917 1918 if (hflag && !suppress_constcond && 1919 mp->m_compares_with_zero && 1920 (ln->tn_op == CON || 1921 (mp->m_binary && op != QUEST && rn->tn_op == CON)) && 1922 /* XXX: rn->tn_system_dependent should be checked as well */ 1923 !ln->tn_system_dependent) 1924 /* constant in conditional context */ 1925 warning(161); 1926 1927 if (mp->m_fold_constant_operands && ln->tn_op == CON) { 1928 if (!mp->m_binary || rn->tn_op == CON) { 1929 if (mp->m_compares_with_zero) 1930 ntn = fold_constant_compare_zero(ntn); 1931 else if (is_floating(ntn->tn_type->t_tspec)) 1932 ntn = fold_constant_floating(ntn); 1933 else 1934 ntn = fold_constant_integer(ntn); 1935 } else if (op == QUEST) { 1936 lint_assert(has_operands(rn)); 1937 use(ln->u.value.u.integer != 0 1938 ? rn->u.ops.right : rn->u.ops.left); 1939 ntn = ln->u.value.u.integer != 0 1940 ? rn->u.ops.left : rn->u.ops.right; 1941 } 1942 } 1943 1944 return ntn; 1945 } 1946 1947 tnode_t * 1948 build_unary(op_t op, bool sys, tnode_t *tn) 1949 { 1950 return build_binary(tn, op, sys, NULL); 1951 } 1952 1953 static bool 1954 are_members_compatible(const sym_t *a, const sym_t *b) 1955 { 1956 if (a->u.s_member.sm_offset_in_bits != b->u.s_member.sm_offset_in_bits) 1957 return false; 1958 1959 const type_t *atp = a->s_type; 1960 const type_t *btp = b->s_type; 1961 bool w = false; 1962 if (!types_compatible(atp, btp, false, false, &w) && !w) 1963 return false; 1964 if (a->s_bitfield != b->s_bitfield) 1965 return false; 1966 if (a->s_bitfield) { 1967 if (atp->t_bit_field_width != btp->t_bit_field_width) 1968 return false; 1969 if (atp->t_bit_field_offset != btp->t_bit_field_offset) 1970 return false; 1971 } 1972 return true; 1973 } 1974 1975 /* 1976 * Return whether all struct/union members with the same name have the same 1977 * type and offset. 1978 */ 1979 static bool 1980 all_members_compatible(const sym_t *msym) 1981 { 1982 for (const sym_t *csym = msym; 1983 csym != NULL; csym = csym->s_symtab_next) { 1984 if (!is_member(csym)) 1985 continue; 1986 if (strcmp(msym->s_name, csym->s_name) != 0) 1987 continue; 1988 1989 for (const sym_t *sym = csym->s_symtab_next; 1990 sym != NULL; sym = sym->s_symtab_next) { 1991 if (is_member(sym) 1992 && strcmp(csym->s_name, sym->s_name) == 0 1993 && !are_members_compatible(csym, sym)) 1994 return false; 1995 } 1996 } 1997 return true; 1998 } 1999 2000 sym_t * 2001 find_member(const struct_or_union *sou, const char *name) 2002 { 2003 for (sym_t *mem = sou->sou_first_member; 2004 mem != NULL; mem = mem->s_next) { 2005 lint_assert(is_member(mem)); 2006 lint_assert(mem->u.s_member.sm_containing_type == sou); 2007 if (strcmp(mem->s_name, name) == 0) 2008 return mem; 2009 } 2010 2011 for (sym_t *mem = sou->sou_first_member; 2012 mem != NULL; mem = mem->s_next) { 2013 if (is_struct_or_union(mem->s_type->t_tspec) 2014 && mem->s_name == unnamed) { 2015 sym_t *nested_mem = 2016 find_member(mem->s_type->u.sou, name); 2017 if (nested_mem != NULL) 2018 return nested_mem; 2019 } 2020 } 2021 return NULL; 2022 } 2023 2024 /* 2025 * Remove the member if it was unknown until now, which means 2026 * that no defined struct or union has a member with the same name. 2027 */ 2028 static void 2029 remove_unknown_member(tnode_t *tn, sym_t *msym) 2030 { 2031 /* type '%s' does not have member '%s' */ 2032 error(101, type_name(tn->tn_type), msym->s_name); 2033 symtab_remove_forever(msym); 2034 msym->s_kind = SK_MEMBER; 2035 msym->s_scl = STRUCT_MEMBER; 2036 2037 struct_or_union *sou = expr_zero_alloc(sizeof(*sou), 2038 "struct_or_union"); 2039 sou->sou_tag = expr_zero_alloc(sizeof(*sou->sou_tag), "sym"); 2040 sou->sou_tag->s_name = unnamed; 2041 2042 msym->u.s_member.sm_containing_type = sou; 2043 /* 2044 * The member sm_offset_in_bits is not needed here since this symbol 2045 * can only be used for error reporting. 2046 */ 2047 } 2048 2049 /* 2050 * Returns a symbol which has the same name as 'msym' and is a member of the 2051 * struct or union specified by 'tn'. 2052 */ 2053 static sym_t * 2054 struct_or_union_member(tnode_t *tn, op_t op, sym_t *msym) 2055 { 2056 2057 /* Determine the tag type of which msym is expected to be a member. */ 2058 const type_t *tp = NULL; 2059 if (op == POINT && is_struct_or_union(tn->tn_type->t_tspec)) 2060 tp = tn->tn_type; 2061 if (op == ARROW && tn->tn_type->t_tspec == PTR 2062 && is_struct_or_union(tn->tn_type->t_subt->t_tspec)) 2063 tp = tn->tn_type->t_subt; 2064 struct_or_union *sou = tp != NULL ? tp->u.sou : NULL; 2065 2066 if (sou != NULL) { 2067 sym_t *nested_mem = find_member(sou, msym->s_name); 2068 if (nested_mem != NULL) 2069 return nested_mem; 2070 } 2071 2072 if (msym->s_scl == NO_SCL) { 2073 remove_unknown_member(tn, msym); 2074 return msym; 2075 } 2076 2077 bool eq = all_members_compatible(msym); 2078 2079 /* 2080 * Now handle the case in which the left operand refers really to a 2081 * struct/union, but the right operand is not member of it. 2082 */ 2083 if (sou != NULL) { 2084 if (eq && !allow_c90) 2085 /* illegal use of member '%s' */ 2086 warning(102, msym->s_name); 2087 else 2088 /* illegal use of member '%s' */ 2089 error(102, msym->s_name); 2090 return msym; 2091 } 2092 2093 if (eq) { 2094 if (op == POINT) { 2095 if (!allow_c90) 2096 /* left operand of '.' must be struct ... */ 2097 warning(103, type_name(tn->tn_type)); 2098 else 2099 /* left operand of '.' must be struct ... */ 2100 error(103, type_name(tn->tn_type)); 2101 } else { 2102 if (!allow_c90 && tn->tn_type->t_tspec == PTR) 2103 /* left operand of '->' must be pointer ... */ 2104 warning(104, type_name(tn->tn_type)); 2105 else 2106 /* left operand of '->' must be pointer ... */ 2107 error(104, type_name(tn->tn_type)); 2108 } 2109 } else { 2110 if (!allow_c90) 2111 /* non-unique member requires struct/union %s */ 2112 error(105, op == POINT ? "object" : "pointer"); 2113 else 2114 /* unacceptable operand of '%s' */ 2115 error(111, op_name(op)); 2116 } 2117 2118 return msym; 2119 } 2120 2121 tnode_t * 2122 build_member_access(tnode_t *ln, op_t op, bool sys, sbuf_t *member) 2123 { 2124 sym_t *msym; 2125 2126 if (ln == NULL) 2127 return NULL; 2128 2129 if (op == ARROW) 2130 /* must do this before struct_or_union_member is called */ 2131 ln = cconv(ln); 2132 msym = struct_or_union_member(ln, op, getsym(member)); 2133 return build_binary(ln, op, sys, build_name(msym, false)); 2134 } 2135 2136 /* 2137 * Perform class conversions. 2138 * 2139 * Arrays of type T are converted into pointers to type T. 2140 * Functions are converted to pointers to functions. 2141 * Lvalues are converted to rvalues. 2142 * 2143 * C99 6.3 "Conversions" 2144 * C99 6.3.2 "Other operands" 2145 * C99 6.3.2.1 "Lvalues, arrays, and function designators" 2146 */ 2147 tnode_t * 2148 cconv(tnode_t *tn) 2149 { 2150 if (tn->tn_type->t_tspec == ARRAY) { 2151 if (!tn->tn_lvalue) { 2152 /* XXX print correct operator */ 2153 /* %soperand of '%s' must be lvalue */ 2154 gnuism(114, "", op_name(ADDR)); 2155 } 2156 tn = build_op(ADDR, tn->tn_sys, 2157 expr_derive_type(tn->tn_type->t_subt, PTR), tn, NULL); 2158 } 2159 2160 if (tn->tn_type->t_tspec == FUNC) 2161 tn = build_address(tn->tn_sys, tn, true); 2162 2163 if (tn->tn_lvalue) { 2164 type_t *tp = expr_dup_type(tn->tn_type); 2165 /* C99 6.3.2.1p2 sentence 2 says to remove the qualifiers. */ 2166 tp->t_const = tp->t_volatile = false; 2167 tn = build_op(LOAD, tn->tn_sys, tp, tn, NULL); 2168 } 2169 2170 return tn; 2171 } 2172 2173 const tnode_t * 2174 before_conversion(const tnode_t *tn) 2175 { 2176 while (tn->tn_op == CVT && !tn->tn_cast) 2177 tn = tn->u.ops.left; 2178 return tn; 2179 } 2180 2181 /* 2182 * Most errors required by C90 are reported in struct_or_union_member(). 2183 * Here we only check for totally wrong things. 2184 */ 2185 static bool 2186 typeok_point(const tnode_t *ln, const type_t *ltp, tspec_t lt) 2187 { 2188 if (is_struct_or_union(lt)) 2189 return true; 2190 2191 if (lt == FUNC || lt == VOID || ltp->t_bitfield) 2192 goto wrong; 2193 2194 /* 2195 * Some C dialects from before C90 tolerated any lvalue on the 2196 * left-hand side of the '.' operator, allowing things like 'char 2197 * st[100]; st.st_mtime', assuming that the member 'st_mtime' only 2198 * occurred in a single struct; see typeok_arrow. 2199 */ 2200 if (ln->tn_lvalue) 2201 return true; 2202 2203 wrong: 2204 /* With allow_c90 we already got an error */ 2205 if (!allow_c90) 2206 /* unacceptable operand of '%s' */ 2207 error(111, op_name(POINT)); 2208 2209 return false; 2210 } 2211 2212 static bool 2213 typeok_arrow(tspec_t lt) 2214 { 2215 /* 2216 * C1978 Appendix A 14.1 says: <quote>In fact, any lvalue is allowed 2217 * before '.', and that lvalue is then assumed to have the form of the 2218 * structure of which the name of the right is a member. [...] Such 2219 * constructions are non-portable.</quote> 2220 */ 2221 if (lt == PTR || (!allow_c90 && is_integer(lt))) 2222 return true; 2223 2224 /* With allow_c90 we already got an error */ 2225 if (!allow_c90) 2226 /* unacceptable operand of '%s' */ 2227 error(111, op_name(ARROW)); 2228 return false; 2229 } 2230 2231 static bool 2232 typeok_incdec(op_t op, const tnode_t *tn, const type_t *tp) 2233 { 2234 /* operand has scalar type (checked in typeok) */ 2235 if (!tn->tn_lvalue) { 2236 if (tn->tn_op == CVT && tn->tn_cast && 2237 tn->u.ops.left->tn_op == LOAD) 2238 /* a cast does not yield an lvalue */ 2239 error(163); 2240 /* %soperand of '%s' must be lvalue */ 2241 error(114, "", op_name(op)); 2242 return false; 2243 } 2244 if (tp->t_const && allow_c90) 2245 /* %soperand of '%s' must be modifiable lvalue */ 2246 warning(115, "", op_name(op)); 2247 return true; 2248 } 2249 2250 static bool 2251 typeok_address(op_t op, const tnode_t *tn, const type_t *tp, tspec_t t) 2252 { 2253 if (t == ARRAY || t == FUNC) { 2254 /* ok, a warning comes later (in build_address()) */ 2255 } else if (!tn->tn_lvalue) { 2256 if (tn->tn_op == CVT && tn->tn_cast && 2257 tn->u.ops.left->tn_op == LOAD) 2258 /* a cast does not yield an lvalue */ 2259 error(163); 2260 /* %soperand of '%s' must be lvalue */ 2261 error(114, "", op_name(op)); 2262 return false; 2263 } else if (is_scalar(t)) { 2264 if (tp->t_bitfield) { 2265 /* cannot take address of bit-field */ 2266 error(112); 2267 return false; 2268 } 2269 } else if (t != STRUCT && t != UNION) { 2270 /* unacceptable operand of '%s' */ 2271 error(111, op_name(op)); 2272 return false; 2273 } 2274 if (tn->tn_op == NAME && tn->u.sym->s_register) { 2275 /* cannot take address of register '%s' */ 2276 error(113, tn->u.sym->s_name); 2277 return false; 2278 } 2279 return true; 2280 } 2281 2282 static bool 2283 typeok_indir(const type_t *tp, tspec_t t) 2284 { 2285 2286 if (t != PTR) { 2287 /* cannot dereference non-pointer type '%s' */ 2288 error(96, type_name(tp)); 2289 return false; 2290 } 2291 return true; 2292 } 2293 2294 static void 2295 warn_incompatible_types(op_t op, 2296 const type_t *ltp, tspec_t lt, 2297 const type_t *rtp, tspec_t rt) 2298 { 2299 bool binary = modtab[op].m_binary; 2300 2301 if (lt == VOID || (binary && rt == VOID)) { 2302 /* void type illegal in expression */ 2303 error(109); 2304 } else if (op == ASSIGN) 2305 /* cannot assign to '%s' from '%s' */ 2306 error(171, type_name(ltp), type_name(rtp)); 2307 else if (binary) 2308 /* operands of '%s' have incompatible types '%s' and '%s' */ 2309 error(107, op_name(op), type_name(ltp), type_name(rtp)); 2310 else { 2311 lint_assert(rt == NO_TSPEC); 2312 /* operand of '%s' has invalid type '%s' */ 2313 error(108, op_name(op), type_name(ltp)); 2314 } 2315 } 2316 2317 static bool 2318 typeok_plus(op_t op, 2319 const type_t *ltp, tspec_t lt, 2320 const type_t *rtp, tspec_t rt) 2321 { 2322 /* operands have scalar types (checked in typeok) */ 2323 if ((lt == PTR && !is_integer(rt)) || (rt == PTR && !is_integer(lt))) { 2324 warn_incompatible_types(op, ltp, lt, rtp, rt); 2325 return false; 2326 } 2327 return true; 2328 } 2329 2330 static bool 2331 typeok_minus(op_t op, 2332 const type_t *ltp, tspec_t lt, 2333 const type_t *rtp, tspec_t rt) 2334 { 2335 /* operands have scalar types (checked in typeok) */ 2336 if ((lt == PTR && rt != PTR && !is_integer(rt)) || 2337 (lt != PTR && rt == PTR)) { 2338 warn_incompatible_types(op, ltp, lt, rtp, rt); 2339 return false; 2340 } 2341 if (lt == PTR && rt == PTR && 2342 !types_compatible(ltp->t_subt, rtp->t_subt, true, false, NULL)) { 2343 /* illegal pointer subtraction */ 2344 error(116); 2345 } 2346 return true; 2347 } 2348 2349 static void 2350 typeok_shr(op_t op, 2351 const tnode_t *ln, tspec_t lt, 2352 const tnode_t *rn, tspec_t rt) 2353 { 2354 tspec_t olt = before_conversion(ln)->tn_type->t_tspec; 2355 tspec_t ort = before_conversion(rn)->tn_type->t_tspec; 2356 2357 /* operands have integer types (checked in typeok) */ 2358 if (pflag && !is_uinteger(olt)) { 2359 integer_constraints lc = ic_expr(ln); 2360 if (!ic_maybe_signed(ln->tn_type, &lc)) 2361 return; 2362 2363 if (ln->tn_op != CON) 2364 /* bitwise '%s' on signed value possibly nonportable */ 2365 warning(117, op_name(op)); 2366 else if (ln->u.value.u.integer < 0) 2367 /* bitwise '%s' on signed value nonportable */ 2368 warning(120, op_name(op)); 2369 } else if (allow_trad && allow_c90 && 2370 !is_uinteger(olt) && is_uinteger(ort)) { 2371 /* The left operand would become unsigned in traditional C. */ 2372 if (hflag && (ln->tn_op != CON || ln->u.value.u.integer < 0)) { 2373 /* semantics of '%s' change in C90; use ... */ 2374 warning(118, op_name(op)); 2375 } 2376 } else if (allow_trad && allow_c90 && 2377 !is_uinteger(olt) && !is_uinteger(ort) && 2378 portable_rank_cmp(lt, rt) < 0) { 2379 /* 2380 * In traditional C, the left operand would be extended 2381 * (possibly sign-extended) and then shifted. 2382 */ 2383 if (hflag && (ln->tn_op != CON || ln->u.value.u.integer < 0)) { 2384 /* semantics of '%s' change in C90; use ... */ 2385 warning(118, op_name(op)); 2386 } 2387 } 2388 } 2389 2390 static void 2391 typeok_shl(op_t op, tspec_t lt, tspec_t rt) 2392 { 2393 /* 2394 * C90 does not perform balancing for shift operations, but traditional 2395 * C does. If the width of the right operand is greater than the width 2396 * of the left operand, then in traditional C the left operand would be 2397 * extended to the width of the right operand. For SHL this may result 2398 * in different results. 2399 */ 2400 if (portable_rank_cmp(lt, rt) < 0) { 2401 /* 2402 * XXX If both operands are constant, make sure that there is 2403 * really a difference between C90 and traditional C. 2404 */ 2405 if (hflag && allow_trad && allow_c90) 2406 /* semantics of '%s' change in C90; use ... */ 2407 warning(118, op_name(op)); 2408 } 2409 } 2410 2411 static void 2412 typeok_shift(const type_t *ltp, tspec_t lt, const tnode_t *rn, tspec_t rt) 2413 { 2414 if (rn->tn_op != CON) 2415 return; 2416 2417 if (!is_uinteger(rt) && rn->u.value.u.integer < 0) 2418 /* negative shift */ 2419 warning(121); 2420 else if ((uint64_t)rn->u.value.u.integer == size_in_bits(lt)) 2421 /* shift amount %u equals bit-size of '%s' */ 2422 warning(267, (unsigned)rn->u.value.u.integer, type_name(ltp)); 2423 else if ((uint64_t)rn->u.value.u.integer > size_in_bits(lt)) { 2424 /* shift amount %llu is greater than bit-size %llu of '%s' */ 2425 warning(122, (unsigned long long)rn->u.value.u.integer, 2426 (unsigned long long)size_in_bits(lt), 2427 tspec_name(lt)); 2428 } 2429 } 2430 2431 static bool 2432 is_typeok_eq(const tnode_t *ln, tspec_t lt, const tnode_t *rn, tspec_t rt) 2433 { 2434 if (lt == PTR && is_null_pointer(rn)) 2435 return true; 2436 if (rt == PTR && is_null_pointer(ln)) 2437 return true; 2438 return false; 2439 } 2440 2441 static void 2442 warn_incompatible_pointers(op_t op, const type_t *ltp, const type_t *rtp) 2443 { 2444 lint_assert(ltp->t_tspec == PTR); 2445 lint_assert(rtp->t_tspec == PTR); 2446 2447 tspec_t lt = ltp->t_subt->t_tspec; 2448 tspec_t rt = rtp->t_subt->t_tspec; 2449 2450 if (is_struct_or_union(lt) && is_struct_or_union(rt)) { 2451 if (op == RETURN) 2452 /* illegal structure pointer combination */ 2453 warning(244); 2454 else { 2455 /* incompatible structure pointers: '%s' '%s' '%s' */ 2456 warning(245, type_name(ltp), 2457 op_name(op), type_name(rtp)); 2458 } 2459 } else { 2460 if (op == RETURN) 2461 /* illegal combination of '%s' and '%s' */ 2462 warning(184, type_name(ltp), type_name(rtp)); 2463 else { 2464 /* illegal combination of '%s' and '%s', op '%s' */ 2465 warning(124, 2466 type_name(ltp), type_name(rtp), op_name(op)); 2467 } 2468 } 2469 } 2470 2471 static void 2472 check_pointer_comparison(op_t op, const tnode_t *ln, const tnode_t *rn) 2473 { 2474 type_t *ltp = ln->tn_type, *rtp = rn->tn_type; 2475 tspec_t lst = ltp->t_subt->t_tspec, rst = rtp->t_subt->t_tspec; 2476 2477 if (lst == VOID || rst == VOID) { 2478 /* TODO: C99 behaves like C90 here. */ 2479 if (!allow_trad && !allow_c99 && 2480 (lst == FUNC || rst == FUNC)) { 2481 /* (void *)0 is already handled in typeok() */ 2482 const char *lsts, *rsts; 2483 *(lst == FUNC ? &lsts : &rsts) = "function pointer"; 2484 *(lst == VOID ? &lsts : &rsts) = "'void *'"; 2485 /* C90 or later forbid comparison of %s with %s */ 2486 warning(274, lsts, rsts); 2487 } 2488 return; 2489 } 2490 2491 if (!types_compatible(ltp->t_subt, rtp->t_subt, true, false, NULL)) { 2492 warn_incompatible_pointers(op, ltp, rtp); 2493 return; 2494 } 2495 2496 if (lst == FUNC && rst == FUNC) { 2497 /* TODO: C99 behaves like C90 here, see C99 6.5.8p2. */ 2498 if (!allow_trad && !allow_c99 && op != EQ && op != NE) 2499 /* pointers to functions can only be compared ... */ 2500 warning(125); 2501 } 2502 } 2503 2504 static bool 2505 typeok_compare(op_t op, 2506 const tnode_t *ln, const type_t *ltp, tspec_t lt, 2507 const tnode_t *rn, const type_t *rtp, tspec_t rt) 2508 { 2509 if (lt == PTR && rt == PTR) { 2510 check_pointer_comparison(op, ln, rn); 2511 return true; 2512 } 2513 2514 if (lt != PTR && rt != PTR) 2515 return true; 2516 2517 if (!is_integer(lt) && !is_integer(rt)) { 2518 warn_incompatible_types(op, ltp, lt, rtp, rt); 2519 return false; 2520 } 2521 2522 const char *lx = lt == PTR ? "pointer" : "integer"; 2523 const char *rx = rt == PTR ? "pointer" : "integer"; 2524 /* illegal combination of %s '%s' and %s '%s', op '%s' */ 2525 warning(123, lx, type_name(ltp), rx, type_name(rtp), op_name(op)); 2526 return true; 2527 } 2528 2529 static bool 2530 typeok_quest(tspec_t lt, const tnode_t *rn) 2531 { 2532 if (!is_scalar(lt)) { 2533 /* first operand of '?' must have scalar type */ 2534 error(170); 2535 return false; 2536 } 2537 lint_assert(before_conversion(rn)->tn_op == COLON); 2538 return true; 2539 } 2540 2541 static void 2542 typeok_colon_pointer(const type_t *ltp, const type_t *rtp) 2543 { 2544 type_t *lstp = ltp->t_subt; 2545 type_t *rstp = rtp->t_subt; 2546 tspec_t lst = lstp->t_tspec; 2547 tspec_t rst = rstp->t_tspec; 2548 2549 if ((lst == VOID && rst == FUNC) || (lst == FUNC && rst == VOID)) { 2550 /* (void *)0 is handled in typeok_colon */ 2551 /* TODO: C99 behaves like C90 here. */ 2552 if (!allow_trad && !allow_c99) 2553 /* conversion of %s to %s requires a cast, op %s */ 2554 warning(305, "function pointer", "'void *'", 2555 op_name(COLON)); 2556 return; 2557 } 2558 2559 if (pointer_types_are_compatible(lstp, rstp, true)) 2560 return; 2561 if (!types_compatible(lstp, rstp, true, false, NULL)) 2562 warn_incompatible_pointers(COLON, ltp, rtp); 2563 } 2564 2565 static bool 2566 typeok_colon(const tnode_t *ln, const type_t *ltp, tspec_t lt, 2567 const tnode_t *rn, const type_t *rtp, tspec_t rt) 2568 { 2569 2570 if (is_arithmetic(lt) && is_arithmetic(rt)) 2571 return true; 2572 if (lt == BOOL && rt == BOOL) 2573 return true; 2574 2575 if (lt == STRUCT && rt == STRUCT && ltp->u.sou == rtp->u.sou) 2576 return true; 2577 if (lt == UNION && rt == UNION && ltp->u.sou == rtp->u.sou) 2578 return true; 2579 2580 if (lt == PTR && is_null_pointer(rn)) 2581 return true; 2582 if (rt == PTR && is_null_pointer(ln)) 2583 return true; 2584 2585 if ((lt == PTR && is_integer(rt)) || (is_integer(lt) && rt == PTR)) { 2586 const char *lx = lt == PTR ? "pointer" : "integer"; 2587 const char *rx = rt == PTR ? "pointer" : "integer"; 2588 /* illegal combination of %s '%s' and %s '%s', op '%s' */ 2589 warning(123, lx, type_name(ltp), 2590 rx, type_name(rtp), op_name(COLON)); 2591 return true; 2592 } 2593 2594 if (lt == VOID || rt == VOID) { 2595 if (lt != VOID || rt != VOID) 2596 /* incompatible types '%s' and '%s' in conditional */ 2597 warning(126, type_name(ltp), type_name(rtp)); 2598 return true; 2599 } 2600 2601 if (lt == PTR && rt == PTR) { 2602 typeok_colon_pointer(ltp, rtp); 2603 return true; 2604 } 2605 2606 /* incompatible types '%s' and '%s' in conditional */ 2607 error(126, type_name(ltp), type_name(rtp)); 2608 return false; 2609 } 2610 2611 static bool 2612 has_constant_member(const type_t *tp) 2613 { 2614 lint_assert(is_struct_or_union(tp->t_tspec)); 2615 2616 for (sym_t *m = tp->u.sou->sou_first_member; 2617 m != NULL; m = m->s_next) { 2618 const type_t *mtp = m->s_type; 2619 if (mtp->t_const) 2620 return true; 2621 if (is_struct_or_union(mtp->t_tspec) && 2622 has_constant_member(mtp)) 2623 return true; 2624 } 2625 return false; 2626 } 2627 2628 static bool 2629 typeok_assign(op_t op, const tnode_t *ln, const type_t *ltp, tspec_t lt) 2630 { 2631 if (op == RETURN || op == INIT || op == FARG) 2632 return true; 2633 2634 if (!ln->tn_lvalue) { 2635 if (ln->tn_op == CVT && ln->tn_cast && 2636 ln->u.ops.left->tn_op == LOAD) 2637 /* a cast does not yield an lvalue */ 2638 error(163); 2639 /* %soperand of '%s' must be lvalue */ 2640 error(114, "left ", op_name(op)); 2641 return false; 2642 } else if (ltp->t_const 2643 || (is_struct_or_union(lt) && has_constant_member(ltp))) { 2644 if (allow_c90) 2645 /* %soperand of '%s' must be modifiable lvalue */ 2646 warning(115, "left ", op_name(op)); 2647 } 2648 return true; 2649 } 2650 2651 static bool 2652 typeok_scalar(op_t op, const mod_t *mp, 2653 const type_t *ltp, tspec_t lt, 2654 const type_t *rtp, tspec_t rt) 2655 { 2656 if (mp->m_takes_bool && lt == BOOL && rt == BOOL) 2657 return true; 2658 if (mp->m_requires_integer) { 2659 if (!is_integer(lt) || (mp->m_binary && !is_integer(rt))) { 2660 warn_incompatible_types(op, ltp, lt, rtp, rt); 2661 return false; 2662 } 2663 } else if (mp->m_requires_integer_or_complex) { 2664 if ((!is_integer(lt) && !is_complex(lt)) || 2665 (mp->m_binary && (!is_integer(rt) && !is_complex(rt)))) { 2666 warn_incompatible_types(op, ltp, lt, rtp, rt); 2667 return false; 2668 } 2669 } else if (mp->m_requires_scalar) { 2670 if (!is_scalar(lt) || (mp->m_binary && !is_scalar(rt))) { 2671 warn_incompatible_types(op, ltp, lt, rtp, rt); 2672 return false; 2673 } 2674 } else if (mp->m_requires_arith) { 2675 if (!is_arithmetic(lt) || 2676 (mp->m_binary && !is_arithmetic(rt))) { 2677 warn_incompatible_types(op, ltp, lt, rtp, rt); 2678 return false; 2679 } 2680 } 2681 return true; 2682 } 2683 2684 static void 2685 check_assign_void_pointer(op_t op, int arg, 2686 tspec_t lt, tspec_t lst, 2687 tspec_t rt, tspec_t rst) 2688 { 2689 2690 if (!(lt == PTR && rt == PTR && (lst == VOID || rst == VOID))) 2691 return; 2692 /* two pointers, at least one pointer to void */ 2693 2694 /* TODO: C99 behaves like C90 here. */ 2695 if (!(!allow_trad && !allow_c99 && (lst == FUNC || rst == FUNC))) 2696 return; 2697 /* comb. of ptr to func and ptr to void */ 2698 2699 const char *lts, *rts; 2700 *(lst == FUNC ? <s : &rts) = "function pointer"; 2701 *(lst == VOID ? <s : &rts) = "'void *'"; 2702 2703 switch (op) { 2704 case INIT: 2705 case RETURN: 2706 /* conversion of %s to %s requires a cast */ 2707 warning(303, rts, lts); 2708 break; 2709 case FARG: 2710 /* conversion of %s to %s requires a cast, arg #%d */ 2711 warning(304, rts, lts, arg); 2712 break; 2713 default: 2714 /* conversion of %s to %s requires a cast, op %s */ 2715 warning(305, rts, lts, op_name(op)); 2716 break; 2717 } 2718 } 2719 2720 static bool 2721 is_direct_function_call(const tnode_t *tn, const char **out_name) 2722 { 2723 2724 if (tn->tn_op == CALL 2725 && tn->u.call->func->tn_op == ADDR 2726 && tn->u.call->func->u.ops.left->tn_op == NAME) { 2727 *out_name = tn->u.call->func->u.ops.left->u.sym->s_name; 2728 return true; 2729 } 2730 return false; 2731 } 2732 2733 static bool 2734 is_unconst_function(const char *name) 2735 { 2736 2737 return strcmp(name, "memchr") == 0 || 2738 strcmp(name, "strchr") == 0 || 2739 strcmp(name, "strpbrk") == 0 || 2740 strcmp(name, "strrchr") == 0 || 2741 strcmp(name, "strstr") == 0; 2742 } 2743 2744 static bool 2745 is_const_char_pointer(const tnode_t *tn) 2746 { 2747 /* 2748 * For traditional reasons, C99 6.4.5p5 defines that string literals 2749 * have type 'char[]'. They are often implicitly converted to 'char 2750 * *', for example when they are passed as function arguments. 2751 * 2752 * C99 6.4.5p6 further defines that modifying a string that is 2753 * constructed from a string literal invokes undefined behavior. 2754 * 2755 * Out of these reasons, string literals are treated as 'effectively 2756 * const' here. 2757 */ 2758 if (tn->tn_op == CVT && 2759 tn->u.ops.left->tn_op == ADDR && 2760 tn->u.ops.left->u.ops.left->tn_op == STRING) 2761 return true; 2762 2763 const type_t *tp = before_conversion(tn)->tn_type; 2764 return tp->t_tspec == PTR && 2765 tp->t_subt->t_tspec == CHAR && 2766 tp->t_subt->t_const; 2767 } 2768 2769 static bool 2770 is_const_pointer(const tnode_t *tn) 2771 { 2772 const type_t *tp = before_conversion(tn)->tn_type; 2773 return tp->t_tspec == PTR && tp->t_subt->t_const; 2774 } 2775 2776 static void 2777 check_unconst_function(const type_t *lstp, const tnode_t *rn) 2778 { 2779 const char *function_name; 2780 2781 if (lstp->t_tspec == CHAR && !lstp->t_const && 2782 is_direct_function_call(rn, &function_name) && 2783 is_unconst_function(function_name) && 2784 rn->u.call->args_len >= 1 && 2785 is_const_char_pointer(rn->u.call->args[0])) { 2786 /* call to '%s' effectively discards 'const' from argument */ 2787 warning(346, function_name); 2788 } 2789 2790 if (!lstp->t_const && 2791 is_direct_function_call(rn, &function_name) && 2792 strcmp(function_name, "bsearch") == 0 && 2793 rn->u.call->args_len >= 2 && 2794 is_const_pointer(rn->u.call->args[1])) { 2795 /* call to '%s' effectively discards 'const' from argument */ 2796 warning(346, function_name); 2797 } 2798 } 2799 2800 static bool 2801 check_assign_void_pointer_compat(op_t op, int arg, 2802 const type_t *ltp, tspec_t lt, 2803 const type_t *lstp, tspec_t lst, 2804 const tnode_t *rn, 2805 const type_t *rtp, tspec_t rt, 2806 const type_t *rstp, tspec_t rst) 2807 { 2808 if (!(lt == PTR && rt == PTR && (lst == VOID || rst == VOID || 2809 types_compatible(lstp, rstp, 2810 true, false, NULL)))) 2811 return false; 2812 2813 /* compatible pointer types (qualifiers ignored) */ 2814 if (allow_c90 && 2815 ((!lstp->t_const && rstp->t_const) || 2816 (!lstp->t_volatile && rstp->t_volatile))) { 2817 /* left side has not all qualifiers of right */ 2818 switch (op) { 2819 case INIT: 2820 case RETURN: 2821 /* incompatible pointer types to '%s' and '%s' */ 2822 warning(182, type_name(lstp), type_name(rstp)); 2823 break; 2824 case FARG: 2825 /* converting '%s' to incompatible '%s' ... */ 2826 warning(153, 2827 type_name(rtp), type_name(ltp), arg); 2828 break; 2829 default: 2830 /* operands of '%s' have incompatible pointer ... */ 2831 warning(128, op_name(op), 2832 type_name(lstp), type_name(rstp)); 2833 break; 2834 } 2835 } 2836 2837 if (allow_c90) 2838 check_unconst_function(lstp, rn); 2839 2840 return true; 2841 } 2842 2843 static bool 2844 check_assign_pointer_integer(op_t op, int arg, 2845 const type_t *ltp, tspec_t lt, 2846 const type_t *rtp, tspec_t rt) 2847 { 2848 2849 if (!((lt == PTR && is_integer(rt)) || (is_integer(lt) && rt == PTR))) 2850 return false; 2851 2852 const char *lx = lt == PTR ? "pointer" : "integer"; 2853 const char *rx = rt == PTR ? "pointer" : "integer"; 2854 2855 switch (op) { 2856 case INIT: 2857 case RETURN: 2858 /* illegal combination of %s '%s' and %s '%s' */ 2859 warning(183, lx, type_name(ltp), rx, type_name(rtp)); 2860 break; 2861 case FARG: 2862 /* illegal combination of %s '%s' and %s '%s', arg #%d */ 2863 warning(154, 2864 lx, type_name(ltp), rx, type_name(rtp), arg); 2865 break; 2866 default: 2867 /* illegal combination of %s '%s' and %s '%s', op '%s' */ 2868 warning(123, 2869 lx, type_name(ltp), rx, type_name(rtp), op_name(op)); 2870 break; 2871 } 2872 return true; 2873 } 2874 2875 static bool 2876 check_assign_pointer(op_t op, int arg, 2877 const type_t *ltp, tspec_t lt, 2878 const type_t *rtp, tspec_t rt) 2879 { 2880 if (!(lt == PTR && rt == PTR)) 2881 return false; 2882 2883 if (op == FARG) 2884 /* converting '%s' to incompatible '%s' for ... */ 2885 warning(153, type_name(rtp), type_name(ltp), arg); 2886 else 2887 warn_incompatible_pointers(op, ltp, rtp); 2888 return true; 2889 } 2890 2891 static void 2892 warn_assign(op_t op, int arg, 2893 const type_t *ltp, tspec_t lt, 2894 const type_t *rtp, tspec_t rt) 2895 { 2896 switch (op) { 2897 case INIT: 2898 /* cannot initialize '%s' from '%s' */ 2899 error(185, type_name(ltp), type_name(rtp)); 2900 break; 2901 case RETURN: 2902 /* function has return type '%s' but returns '%s' */ 2903 error(211, type_name(ltp), type_name(rtp)); 2904 break; 2905 case FARG: 2906 /* passing '%s' to incompatible '%s', arg #%d */ 2907 warning(155, type_name(rtp), type_name(ltp), arg); 2908 break; 2909 default: 2910 warn_incompatible_types(op, ltp, lt, rtp, rt); 2911 break; 2912 } 2913 } 2914 2915 /* 2916 * Checks type compatibility for ASSIGN, INIT, FARG and RETURN 2917 * and prints warnings/errors if necessary. 2918 * Returns whether the types are (almost) compatible. 2919 */ 2920 static bool 2921 check_assign_types_compatible(op_t op, int arg, 2922 const tnode_t *ln, const tnode_t *rn) 2923 { 2924 tspec_t lt, rt, lst = NO_TSPEC, rst = NO_TSPEC; 2925 type_t *ltp, *rtp, *lstp = NULL, *rstp = NULL; 2926 2927 if ((lt = (ltp = ln->tn_type)->t_tspec) == PTR) 2928 lst = (lstp = ltp->t_subt)->t_tspec; 2929 if ((rt = (rtp = rn->tn_type)->t_tspec) == PTR) 2930 rst = (rstp = rtp->t_subt)->t_tspec; 2931 2932 if (lt == BOOL && is_scalar(rt)) /* C99 6.3.1.2 */ 2933 return true; 2934 2935 if (is_arithmetic(lt) && (is_arithmetic(rt) || rt == BOOL)) 2936 return true; 2937 2938 if (is_struct_or_union(lt) && is_struct_or_union(rt)) 2939 return ltp->u.sou == rtp->u.sou; 2940 2941 if (lt == PTR && is_null_pointer(rn)) { 2942 if (is_integer(rn->tn_type->t_tspec)) 2943 /* implicit conversion from integer 0 to pointer ... */ 2944 query_message(15, type_name(ltp)); 2945 return true; 2946 } 2947 2948 check_assign_void_pointer(op, arg, lt, lst, rt, rst); 2949 2950 if (check_assign_void_pointer_compat(op, arg, 2951 ltp, lt, lstp, lst, rn, rtp, rt, rstp, rst)) 2952 return true; 2953 2954 if (check_assign_pointer_integer(op, arg, ltp, lt, rtp, rt)) 2955 return true; 2956 2957 if (check_assign_pointer(op, arg, ltp, lt, rtp, rt)) 2958 return true; 2959 2960 warn_assign(op, arg, ltp, lt, rtp, rt); 2961 return false; 2962 } 2963 2964 static bool 2965 has_side_effect(const tnode_t *tn) /* NOLINT(misc-no-recursion) */ 2966 { 2967 op_t op = tn->tn_op; 2968 2969 if (modtab[op].m_has_side_effect) 2970 return true; 2971 2972 if (op == CVT && tn->tn_type->t_tspec == VOID) 2973 return has_side_effect(tn->u.ops.left); 2974 2975 /* XXX: Why not has_side_effect(tn->u.ops.left) as well? */ 2976 if (op == LOGAND || op == LOGOR) 2977 return has_side_effect(tn->u.ops.right); 2978 2979 /* XXX: Why not has_side_effect(tn->u.ops.left) as well? */ 2980 if (op == QUEST) 2981 return has_side_effect(tn->u.ops.right); 2982 2983 if (op == COLON || op == COMMA) { 2984 return has_side_effect(tn->u.ops.left) || 2985 has_side_effect(tn->u.ops.right); 2986 } 2987 2988 return false; 2989 } 2990 2991 static bool 2992 is_void_cast(const tnode_t *tn) 2993 { 2994 2995 return tn->tn_op == CVT && tn->tn_cast && 2996 tn->tn_type->t_tspec == VOID; 2997 } 2998 2999 static bool 3000 is_local_symbol(const tnode_t *tn) 3001 { 3002 3003 return tn->tn_op == LOAD && 3004 tn->u.ops.left->tn_op == NAME && 3005 tn->u.ops.left->u.sym->s_scl == AUTO; 3006 } 3007 3008 static bool 3009 is_int_constant_zero(const tnode_t *tn) 3010 { 3011 3012 return tn->tn_op == CON && 3013 tn->tn_type->t_tspec == INT && 3014 tn->u.value.u.integer == 0; 3015 } 3016 3017 static void 3018 check_null_effect(const tnode_t *tn) 3019 { 3020 3021 if (hflag && 3022 !has_side_effect(tn) && 3023 !(is_void_cast(tn) && is_local_symbol(tn->u.ops.left)) && 3024 !(is_void_cast(tn) && is_int_constant_zero(tn->u.ops.left))) { 3025 /* expression has null effect */ 3026 warning(129); 3027 } 3028 } 3029 3030 /* 3031 * Check the types for specific operators and type combinations. 3032 * 3033 * At this point, the operands already conform to the type requirements of 3034 * the operator, such as being integer, floating or scalar. 3035 */ 3036 static bool 3037 typeok_op(op_t op, int arg, 3038 const tnode_t *ln, const type_t *ltp, tspec_t lt, 3039 const tnode_t *rn, const type_t *rtp, tspec_t rt) 3040 { 3041 switch (op) { 3042 case ARROW: 3043 return typeok_arrow(lt); 3044 case POINT: 3045 return typeok_point(ln, ltp, lt); 3046 case INCBEF: 3047 case DECBEF: 3048 case INCAFT: 3049 case DECAFT: 3050 return typeok_incdec(op, ln, ltp); 3051 case INDIR: 3052 return typeok_indir(ltp, lt); 3053 case ADDR: 3054 return typeok_address(op, ln, ltp, lt); 3055 case PLUS: 3056 return typeok_plus(op, ltp, lt, rtp, rt); 3057 case MINUS: 3058 return typeok_minus(op, ltp, lt, rtp, rt); 3059 case SHL: 3060 typeok_shl(op, lt, rt); 3061 goto shift; 3062 case SHR: 3063 typeok_shr(op, ln, lt, rn, rt); 3064 shift: 3065 typeok_shift(ltp, lt, rn, rt); 3066 break; 3067 case LT: 3068 case LE: 3069 case GT: 3070 case GE: 3071 compare: 3072 return typeok_compare(op, ln, ltp, lt, rn, rtp, rt); 3073 case EQ: 3074 case NE: 3075 if (is_typeok_eq(ln, lt, rn, rt)) 3076 break; 3077 goto compare; 3078 case QUEST: 3079 return typeok_quest(lt, rn); 3080 case COLON: 3081 return typeok_colon(ln, ltp, lt, rn, rtp, rt); 3082 case ASSIGN: 3083 case INIT: 3084 case FARG: 3085 case RETURN: 3086 if (!check_assign_types_compatible(op, arg, ln, rn)) 3087 return false; 3088 goto assign; 3089 case MULASS: 3090 case DIVASS: 3091 case MODASS: 3092 goto assign; 3093 case ADDASS: 3094 case SUBASS: 3095 if ((lt == PTR && !is_integer(rt)) || rt == PTR) { 3096 warn_incompatible_types(op, ltp, lt, rtp, rt); 3097 return false; 3098 } 3099 goto assign; 3100 case SHLASS: 3101 goto assign; 3102 case SHRASS: 3103 if (pflag && !is_uinteger(lt) && 3104 !(!allow_c90 && is_uinteger(rt))) { 3105 /* bitwise '%s' on signed value possibly nonportable */ 3106 warning(117, op_name(op)); 3107 } 3108 goto assign; 3109 case ANDASS: 3110 case XORASS: 3111 case ORASS: 3112 assign: 3113 return typeok_assign(op, ln, ltp, lt); 3114 case COMMA: 3115 if (!modtab[ln->tn_op].m_has_side_effect) 3116 check_null_effect(ln); 3117 break; 3118 default: 3119 break; 3120 } 3121 return true; 3122 } 3123 3124 static void 3125 check_bad_enum_operation(op_t op, const tnode_t *ln, const tnode_t *rn) 3126 { 3127 3128 if (!eflag) 3129 return; 3130 3131 /* Allow enum in array indices. */ 3132 if (op == PLUS && 3133 ((ln->tn_type->t_is_enum && rn->tn_type->t_tspec == PTR) || 3134 (rn->tn_type->t_is_enum && ln->tn_type->t_tspec == PTR))) { 3135 return; 3136 } 3137 3138 /* dubious operation '%s' on enum */ 3139 warning(241, op_name(op)); 3140 } 3141 3142 static void 3143 check_enum_type_mismatch(op_t op, int arg, const tnode_t *ln, const tnode_t *rn) 3144 { 3145 const mod_t *mp = &modtab[op]; 3146 3147 if (ln->tn_type->u.enumer != rn->tn_type->u.enumer) { 3148 switch (op) { 3149 case INIT: 3150 /* enum type mismatch between '%s' and '%s' in ... */ 3151 warning(210, 3152 type_name(ln->tn_type), type_name(rn->tn_type)); 3153 break; 3154 case FARG: 3155 /* function expects '%s', passing '%s' for arg #%d */ 3156 warning(156, 3157 type_name(ln->tn_type), type_name(rn->tn_type), 3158 arg); 3159 break; 3160 case RETURN: 3161 /* function has return type '%s' but returns '%s' */ 3162 warning(211, 3163 type_name(ln->tn_type), type_name(rn->tn_type)); 3164 break; 3165 default: 3166 /* enum type mismatch: '%s' '%s' '%s' */ 3167 warning(130, type_name(ln->tn_type), op_name(op), 3168 type_name(rn->tn_type)); 3169 break; 3170 } 3171 } else if (Pflag && eflag && mp->m_comparison && op != EQ && op != NE) 3172 /* operator '%s' assumes that '%s' is ordered */ 3173 warning(243, op_name(op), type_name(ln->tn_type)); 3174 } 3175 3176 static void 3177 check_enum_int_mismatch(op_t op, int arg, const tnode_t *ln, const tnode_t *rn) 3178 { 3179 3180 if (!eflag) 3181 return; 3182 3183 switch (op) { 3184 case INIT: 3185 /* 3186 * Initialization with 0 is allowed. Otherwise, all implicit 3187 * initializations would need to be warned upon as well. 3188 */ 3189 if (!rn->tn_type->t_is_enum && rn->tn_op == CON && 3190 is_integer(rn->tn_type->t_tspec) && 3191 rn->u.value.u.integer == 0) { 3192 return; 3193 } 3194 /* initialization of '%s' with '%s' */ 3195 warning(277, type_name(ln->tn_type), type_name(rn->tn_type)); 3196 break; 3197 case FARG: 3198 /* combination of '%s' and '%s', arg #%d */ 3199 warning(278, 3200 type_name(ln->tn_type), type_name(rn->tn_type), arg); 3201 break; 3202 case RETURN: 3203 /* combination of '%s' and '%s' in return */ 3204 warning(279, type_name(ln->tn_type), type_name(rn->tn_type)); 3205 break; 3206 default: 3207 /* combination of '%s' and '%s', op '%s' */ 3208 warning(242, type_name(ln->tn_type), type_name(rn->tn_type), 3209 op_name(op)); 3210 break; 3211 } 3212 } 3213 3214 static void 3215 typeok_enum(op_t op, const mod_t *mp, int arg, 3216 const tnode_t *ln, const type_t *ltp, 3217 const tnode_t *rn, const type_t *rtp) 3218 { 3219 if (mp->m_bad_on_enum && 3220 (ltp->t_is_enum || (mp->m_binary && rtp->t_is_enum))) { 3221 check_bad_enum_operation(op, ln, rn); 3222 } else if (mp->m_valid_on_enum && 3223 (ltp->t_is_enum && rtp != NULL && rtp->t_is_enum)) { 3224 check_enum_type_mismatch(op, arg, ln, rn); 3225 } else if (mp->m_valid_on_enum && 3226 (ltp->t_is_enum || (rtp != NULL && rtp->t_is_enum))) { 3227 check_enum_int_mismatch(op, arg, ln, rn); 3228 } 3229 } 3230 3231 /* Perform most type checks. Return whether the types are ok. */ 3232 bool 3233 typeok(op_t op, int arg, const tnode_t *ln, const tnode_t *rn) 3234 { 3235 3236 const mod_t *mp = &modtab[op]; 3237 3238 type_t *ltp = ln->tn_type; 3239 tspec_t lt = ltp->t_tspec; 3240 3241 type_t *rtp = mp->m_binary ? rn->tn_type : NULL; 3242 tspec_t rt = mp->m_binary ? rtp->t_tspec : NO_TSPEC; 3243 3244 if (Tflag && !typeok_scalar_strict_bool(op, mp, arg, ln, rn)) 3245 return false; 3246 if (!typeok_scalar(op, mp, ltp, lt, rtp, rt)) 3247 return false; 3248 3249 if (!typeok_op(op, arg, ln, ltp, lt, rn, rtp, rt)) 3250 return false; 3251 3252 typeok_enum(op, mp, arg, ln, ltp, rn, rtp); 3253 return true; 3254 } 3255 3256 /* In traditional C, keep unsigned and promote FLOAT to DOUBLE. */ 3257 static tspec_t 3258 promote_trad(tspec_t t) 3259 { 3260 3261 if (t == UCHAR || t == USHORT) 3262 return UINT; 3263 if (t == CHAR || t == SCHAR || t == SHORT) 3264 return INT; 3265 if (t == FLOAT) 3266 return DOUBLE; 3267 if (t == ENUM) 3268 return INT; 3269 return t; 3270 } 3271 3272 /* 3273 * C99 6.3.1.1p2 requires for types with lower rank than int that "If an int 3274 * can represent all the values of the original type, the value is converted 3275 * to an int; otherwise it is converted to an unsigned int", and that "All 3276 * other types are unchanged by the integer promotions". 3277 */ 3278 static tspec_t 3279 promote_c90(const tnode_t *tn, tspec_t t, bool farg) 3280 { 3281 if (tn->tn_type->t_bitfield) { 3282 unsigned int width = tn->tn_type->t_bit_field_width; 3283 unsigned int int_width = size_in_bits(INT); 3284 // XXX: What about _Bool bit-fields, since C99? 3285 if (width < int_width) 3286 return INT; 3287 if (width == int_width) 3288 return is_uinteger(t) ? UINT : INT; 3289 return t; 3290 } 3291 3292 if (t == CHAR || t == SCHAR) 3293 return INT; 3294 if (t == UCHAR) 3295 return size_in_bits(CHAR) < size_in_bits(INT) ? INT : UINT; 3296 if (t == SHORT) 3297 return INT; 3298 if (t == USHORT) 3299 return size_in_bits(SHORT) < size_in_bits(INT) ? INT : UINT; 3300 if (t == ENUM) 3301 return INT; 3302 if (farg && t == FLOAT) 3303 return DOUBLE; 3304 return t; 3305 } 3306 3307 /* 3308 * Performs the "integer promotions" (C99 6.3.1.1p2), which convert small 3309 * integer types to either int or unsigned int. 3310 * 3311 * If allow_c90 is unset or the operand is a function argument with no type 3312 * information (no prototype or variable # of args), converts float to double. 3313 */ 3314 tnode_t * 3315 promote(op_t op, bool farg, tnode_t *tn) 3316 { 3317 3318 const type_t *otp = tn->tn_type; 3319 tspec_t ot = otp->t_tspec; 3320 if (!is_arithmetic(ot)) 3321 return tn; 3322 3323 tspec_t nt = allow_c90 ? promote_c90(tn, ot, farg) : promote_trad(ot); 3324 if (nt == ot) 3325 return tn; 3326 3327 type_t *ntp = expr_dup_type(gettyp(nt)); 3328 ntp->t_tspec = nt; 3329 ntp->t_is_enum = otp->t_is_enum; 3330 if (ntp->t_is_enum) 3331 ntp->u.enumer = otp->u.enumer; 3332 ntp->t_bitfield = otp->t_bitfield; 3333 if (ntp->t_bitfield) { 3334 ntp->t_bit_field_width = otp->t_bit_field_width; 3335 ntp->t_bit_field_offset = otp->t_bit_field_offset; 3336 } 3337 if (ntp->t_bitfield && is_uinteger(ot) && !is_uinteger(nt)) 3338 ntp->t_bit_field_width++; 3339 return convert(op, 0, ntp, tn); 3340 } 3341 3342 static void 3343 check_lossy_floating_to_integer_conversion( 3344 op_t op, int arg, const type_t *tp, const tnode_t *tn) 3345 { 3346 long double x = tn->u.value.u.floating; 3347 integer_constraints ic = ic_any(tp); 3348 if (is_uinteger(tp->t_tspec) 3349 ? x >= ic.umin && x <= ic.umax && x == (uint64_t)x 3350 : x >= ic.smin && x <= ic.smax && x == (int64_t)x) 3351 return; 3352 if (op == FARG) 3353 /* lossy conversion of %Lg to '%s', arg #%d */ 3354 warning(380, x, type_name(tp), arg); 3355 else 3356 /* lossy conversion of %Lg to '%s' */ 3357 warning(381, x, type_name(tp)); 3358 } 3359 3360 static void 3361 convert_integer_from_floating( 3362 op_t op, int arg, const type_t *tp, const tnode_t *tn) 3363 { 3364 3365 if (op == CVT) 3366 /* cast from floating point '%s' to integer '%s' */ 3367 query_message(2, type_name(tn->tn_type), type_name(tp)); 3368 else 3369 /* implicit conversion from floating point '%s' to ... */ 3370 query_message(1, type_name(tn->tn_type), type_name(tp)); 3371 if (tn->tn_op == CON) 3372 check_lossy_floating_to_integer_conversion(op, arg, tp, tn); 3373 } 3374 3375 static bool 3376 should_warn_about_prototype_conversion(tspec_t nt, 3377 tspec_t ot, const tnode_t *ptn) 3378 { 3379 3380 if (nt == ot) 3381 return false; 3382 3383 if (nt == ENUM && ot == INT) 3384 return false; 3385 3386 if (is_floating(nt) != is_floating(ot) || 3387 portable_rank_cmp(nt, ot) != 0) { 3388 /* representation and/or width change */ 3389 if (!is_integer(ot)) 3390 return true; 3391 /* 3392 * XXX: Investigate whether this rule makes sense; see 3393 * tests/usr.bin/xlint/lint1/platform_long.c. 3394 */ 3395 return portable_rank_cmp(ot, INT) > 0; 3396 } 3397 3398 if (!hflag) 3399 return false; 3400 3401 /* 3402 * If the types differ only in sign and the argument has the same 3403 * representation in both types, print no warning. 3404 */ 3405 if (ptn->tn_op == CON && is_integer(nt) && 3406 signed_type(nt) == signed_type(ot) && 3407 !msb(ptn->u.value.u.integer, ot)) 3408 return false; 3409 3410 return true; 3411 } 3412 3413 /* 3414 * Warn if a prototype causes a type conversion that is different from what 3415 * would happen to the same argument in the absence of a prototype. This 3416 * check is intended for code that needs to stay compatible with pre-C90 C. 3417 * 3418 * Errors/warnings about illegal type combinations are already printed 3419 * in check_assign_types_compatible(). 3420 */ 3421 static void 3422 check_prototype_conversion(int arg, tspec_t nt, tspec_t ot, type_t *tp, 3423 tnode_t *tn) 3424 { 3425 3426 if (!is_arithmetic(nt) || !is_arithmetic(ot)) 3427 return; 3428 3429 /* 3430 * If the type of the formal parameter is char/short, a warning would 3431 * be useless, because functions declared the old style can't expect 3432 * char/short arguments. 3433 */ 3434 if (nt == CHAR || nt == SCHAR || nt == UCHAR || 3435 nt == SHORT || nt == USHORT) 3436 return; 3437 3438 tnode_t *ptn = promote(NOOP, true, tn); 3439 ot = ptn->tn_type->t_tspec; 3440 3441 if (should_warn_about_prototype_conversion(nt, ot, ptn)) { 3442 /* argument %d is converted from '%s' to '%s' ... */ 3443 warning(259, arg, type_name(tn->tn_type), type_name(tp)); 3444 } 3445 } 3446 3447 /* 3448 * When converting a large integer type to a small integer type, in some 3449 * cases the value of the actual expression is further restricted than the 3450 * type bounds, such as in (expr & 0xFF) or (expr % 100) or (expr >> 24). 3451 */ 3452 static bool 3453 can_represent(const type_t *tp, const tnode_t *tn) 3454 { 3455 uint64_t nmask = value_bits(width_in_bits(tp)); 3456 if (!is_uinteger(tp->t_tspec)) 3457 nmask >>= 1; 3458 3459 integer_constraints c = ic_expr(tn); 3460 if ((~c.bclr & ~nmask) == 0) 3461 return true; 3462 3463 integer_constraints tpc = ic_any(tp); 3464 if (is_uinteger(tp->t_tspec) 3465 ? tpc.umin <= c.umin && tpc.umax >= c.umax 3466 : tpc.smin <= c.smin && tpc.smax >= c.smax) 3467 return true; 3468 3469 debug_enter(); 3470 debug_step("type '%s' cannot represent:", type_name(tp)); 3471 debug_node(tn); 3472 debug_leave(); 3473 return false; 3474 } 3475 3476 static bool 3477 should_warn_about_integer_conversion(const type_t *ntp, tspec_t nt, 3478 const tnode_t *otn, tspec_t ot) 3479 { 3480 3481 // XXX: The portable_rank_cmp aims at portable mode, independent of the 3482 // current platform, while can_represent acts on the actual type sizes 3483 // from the current platform. This mix is inconsistent, but anything 3484 // else would make the exact conditions too complicated to grasp. 3485 if (aflag > 0 && portable_rank_cmp(nt, ot) < 0) { 3486 if (ot == LONG || ot == ULONG 3487 || ot == LLONG || ot == ULLONG 3488 #ifdef INT128_SIZE 3489 || ot == INT128 || ot == UINT128 3490 #endif 3491 || aflag > 1) 3492 return !can_represent(ntp, otn); 3493 } 3494 return false; 3495 } 3496 3497 static void 3498 convert_integer_from_integer(op_t op, int arg, tspec_t nt, tspec_t ot, 3499 type_t *tp, tnode_t *tn) 3500 { 3501 3502 if (tn->tn_op == CON) 3503 return; 3504 3505 if (op == CVT) 3506 return; 3507 3508 if (Pflag && pflag && aflag > 0 && 3509 portable_rank_cmp(nt, ot) > 0 && 3510 is_uinteger(nt) != is_uinteger(ot)) { 3511 if (op == FARG) 3512 /* conversion to '%s' may sign-extend ... */ 3513 warning(297, type_name(tp), arg); 3514 else 3515 /* conversion to '%s' may sign-extend ... */ 3516 warning(131, type_name(tp)); 3517 } 3518 3519 if (Pflag && portable_rank_cmp(nt, ot) > 0 && 3520 (tn->tn_op == PLUS || tn->tn_op == MINUS || tn->tn_op == MULT || 3521 tn->tn_op == SHL)) { 3522 /* suggest cast from '%s' to '%s' on op '%s' to ... */ 3523 warning(324, type_name(gettyp(ot)), type_name(tp), 3524 op_name(tn->tn_op)); 3525 } 3526 3527 if (should_warn_about_integer_conversion(tp, nt, tn, ot)) { 3528 if (op == FARG) { 3529 /* conversion from '%s' to '%s' may lose ... */ 3530 warning(298, 3531 type_name(tn->tn_type), type_name(tp), arg); 3532 } else { 3533 /* conversion from '%s' to '%s' may lose accuracy */ 3534 warning(132, 3535 type_name(tn->tn_type), type_name(tp)); 3536 } 3537 } 3538 3539 if (any_query_enabled && is_uinteger(nt) != is_uinteger(ot)) 3540 /* implicit conversion changes sign from '%s' to '%s' */ 3541 query_message(3, type_name(tn->tn_type), type_name(tp)); 3542 } 3543 3544 static void 3545 convert_integer_from_pointer(op_t op, tspec_t nt, type_t *tp, tnode_t *tn) 3546 { 3547 3548 if (tn->tn_op == CON) 3549 return; 3550 if (op != CVT) 3551 return; /* We already got an error. */ 3552 if (portable_rank_cmp(nt, PTR) >= 0) 3553 return; 3554 3555 if (pflag && size_in_bits(nt) >= size_in_bits(PTR)) { 3556 /* conversion of pointer to '%s' may lose bits */ 3557 warning(134, type_name(tp)); 3558 } else { 3559 /* conversion of pointer to '%s' loses bits */ 3560 warning(133, type_name(tp)); 3561 } 3562 } 3563 3564 static bool 3565 struct_starts_with(const type_t *struct_tp, const type_t *member_tp) 3566 { 3567 3568 return struct_tp->u.sou->sou_first_member != NULL && 3569 types_compatible(struct_tp->u.sou->sou_first_member->s_type, 3570 member_tp, true, false, NULL); 3571 } 3572 3573 static bool 3574 is_byte_array(const type_t *tp) 3575 { 3576 3577 return tp->t_tspec == ARRAY && 3578 (tp->t_subt->t_tspec == CHAR || tp->t_subt->t_tspec == UCHAR); 3579 } 3580 3581 static bool 3582 union_contains(const type_t *utp, const type_t *mtp) 3583 { 3584 for (const sym_t *mem = utp->u.sou->sou_first_member; 3585 mem != NULL; mem = mem->s_next) { 3586 if (types_compatible(mem->s_type, mtp, true, false, NULL)) 3587 return true; 3588 } 3589 return false; 3590 } 3591 3592 static bool 3593 should_warn_about_pointer_cast(const type_t *nstp, tspec_t nst, 3594 const type_t *ostp, tspec_t ost) 3595 { 3596 3597 while (nst == ARRAY) 3598 nstp = nstp->t_subt, nst = nstp->t_tspec; 3599 while (ost == ARRAY) 3600 ostp = ostp->t_subt, ost = ostp->t_tspec; 3601 3602 if (nst == STRUCT && ost == STRUCT && 3603 (struct_starts_with(nstp, ostp) || 3604 struct_starts_with(ostp, nstp))) 3605 return false; 3606 3607 if (is_incomplete(nstp) || is_incomplete(ostp)) 3608 return false; 3609 3610 if (nst == CHAR || nst == UCHAR) 3611 return false; /* for the sake of traditional C code */ 3612 if (ost == CHAR || ost == UCHAR) 3613 return false; /* for the sake of traditional C code */ 3614 3615 /* Allow cast between pointers to sockaddr variants. */ 3616 if (nst == STRUCT && ost == STRUCT) { 3617 const sym_t *nmem = nstp->u.sou->sou_first_member; 3618 const sym_t *omem = ostp->u.sou->sou_first_member; 3619 while (nmem != NULL && omem != NULL && 3620 types_compatible(nmem->s_type, omem->s_type, 3621 true, false, NULL)) 3622 nmem = nmem->s_next, omem = omem->s_next; 3623 if (nmem != NULL && is_byte_array(nmem->s_type)) 3624 return false; 3625 if (omem != NULL && is_byte_array(omem->s_type)) 3626 return false; 3627 if (nmem == NULL && omem == NULL) 3628 return false; 3629 } 3630 3631 if (nst == UNION || ost == UNION) { 3632 const type_t *union_tp = nst == UNION ? nstp : ostp; 3633 const type_t *other_tp = nst == UNION ? ostp : nstp; 3634 if (union_contains(union_tp, other_tp)) 3635 return false; 3636 } 3637 3638 if (is_struct_or_union(nst) && is_struct_or_union(ost)) 3639 return nstp->u.sou != ostp->u.sou; 3640 3641 enum rank_kind rk1 = type_properties(nst)->tt_rank_kind; 3642 enum rank_kind rk2 = type_properties(ost)->tt_rank_kind; 3643 if (rk1 != rk2 || rk1 == RK_NONE) 3644 return true; 3645 3646 return portable_rank_cmp(nst, ost) != 0; 3647 } 3648 3649 static void 3650 convert_pointer_from_pointer(type_t *ntp, tnode_t *tn) 3651 { 3652 const type_t *nstp = ntp->t_subt; 3653 const type_t *otp = tn->tn_type; 3654 const type_t *ostp = otp->t_subt; 3655 tspec_t nst = nstp->t_tspec; 3656 tspec_t ost = ostp->t_tspec; 3657 3658 if (nst == VOID || ost == VOID) { 3659 /* TODO: C99 behaves like C90 here. */ 3660 if (!allow_trad && !allow_c99 && (nst == FUNC || ost == FUNC)) { 3661 const char *nts, *ots; 3662 /* null pointers are already handled in convert() */ 3663 *(nst == FUNC ? &nts : &ots) = "function pointer"; 3664 *(nst == VOID ? &nts : &ots) = "'void *'"; 3665 /* conversion of %s to %s requires a cast */ 3666 warning(303, ots, nts); 3667 } 3668 return; 3669 } 3670 if (nst == FUNC && ost == FUNC) 3671 return; 3672 if (nst == FUNC || ost == FUNC) { 3673 /* converting '%s' to '%s' is questionable */ 3674 warning(229, type_name(otp), type_name(ntp)); 3675 return; 3676 } 3677 3678 if (hflag && alignment(nstp) > alignment(ostp) && 3679 ost != CHAR && ost != UCHAR && 3680 !is_incomplete(ostp) && 3681 !(nst == UNION && union_contains(nstp, ostp))) { 3682 /* converting '%s' to '%s' increases alignment ... */ 3683 warning(135, type_name(otp), type_name(ntp), 3684 alignment(ostp), alignment(nstp)); 3685 } 3686 3687 if (cflag && should_warn_about_pointer_cast(nstp, nst, ostp, ost)) { 3688 /* pointer cast from '%s' to unrelated '%s' */ 3689 warning(247, type_name(ostp), type_name(nstp)); 3690 } 3691 } 3692 3693 /* 3694 * Insert a conversion operator, which converts the type of the node 3695 * to another given type. 3696 * 3697 * Possible values for 'op': 3698 * CVT a cast-expression 3699 * binary integer promotion for one of the operands, or a usual 3700 * arithmetic conversion 3701 * binary plain or compound assignments to bit-fields 3702 * FARG 'arg' is the number of the parameter (used for warnings) 3703 * NOOP several other implicit conversions 3704 * ... 3705 */ 3706 tnode_t * 3707 convert(op_t op, int arg, type_t *tp, tnode_t *tn) 3708 { 3709 tspec_t nt = tp->t_tspec; 3710 tspec_t ot = tn->tn_type->t_tspec; 3711 3712 if (allow_trad && allow_c90 && op == FARG) 3713 check_prototype_conversion(arg, nt, ot, tp, tn); 3714 3715 if (nt == BOOL) { 3716 /* No further checks. */ 3717 3718 } else if (is_integer(nt)) { 3719 if (ot == BOOL) { 3720 /* No further checks. */ 3721 } else if (is_integer(ot)) 3722 convert_integer_from_integer(op, arg, nt, ot, tp, tn); 3723 else if (is_floating(ot)) 3724 convert_integer_from_floating(op, arg, tp, tn); 3725 else if (ot == PTR) 3726 convert_integer_from_pointer(op, nt, tp, tn); 3727 3728 } else if (is_floating(nt)) { 3729 if (is_integer(ot) && op != CVT) { 3730 /* implicit conversion from integer '%s' to ... */ 3731 query_message(19, 3732 type_name(tn->tn_type), type_name(tp)); 3733 } 3734 3735 } else if (nt == PTR) { 3736 if (is_null_pointer(tn)) { 3737 /* a null pointer may be assigned to any pointer. */ 3738 } else if (ot == PTR && op == CVT) 3739 convert_pointer_from_pointer(tp, tn); 3740 } 3741 3742 tnode_t *ntn = expr_alloc_tnode(); 3743 ntn->tn_op = CVT; 3744 ntn->tn_type = tp; 3745 ntn->tn_cast = op == CVT; 3746 ntn->tn_sys |= tn->tn_sys; 3747 ntn->u.ops.right = NULL; 3748 if (tn->tn_op != CON || nt == VOID) { 3749 ntn->u.ops.left = tn; 3750 } else { 3751 ntn->tn_op = CON; 3752 convert_constant(op, arg, ntn->tn_type, &ntn->u.value, 3753 &tn->u.value); 3754 } 3755 3756 return ntn; 3757 } 3758 3759 static void 3760 convert_constant_from_floating(op_t op, int arg, const type_t *ntp, 3761 tspec_t nt, val_t *nv, val_t *ov) 3762 { 3763 long double max = 0.0, min = 0.0; 3764 3765 switch (nt) { 3766 case CHAR: 3767 max = TARG_CHAR_MAX; min = TARG_CHAR_MIN; break; 3768 case UCHAR: 3769 max = TARG_UCHAR_MAX; min = 0; break; 3770 case SCHAR: 3771 max = TARG_SCHAR_MAX; min = TARG_SCHAR_MIN; break; 3772 case SHORT: 3773 max = TARG_SHRT_MAX; min = TARG_SHRT_MIN; break; 3774 case USHORT: 3775 max = TARG_USHRT_MAX; min = 0; break; 3776 case ENUM: 3777 case INT: 3778 max = TARG_INT_MAX; min = TARG_INT_MIN; break; 3779 case UINT: 3780 max = TARG_UINT_MAX; min = 0; break; 3781 case LONG: 3782 max = TARG_LONG_MAX; min = TARG_LONG_MIN; break; 3783 case ULONG: 3784 max = TARG_ULONG_MAX; min = 0; break; 3785 case LLONG: 3786 max = LLONG_MAX; min = LLONG_MIN; break; 3787 case ULLONG: 3788 max = ULLONG_MAX; min = 0; break; 3789 case FLOAT: 3790 case FCOMPLEX: 3791 max = FLT_MAX; min = -FLT_MAX; break; 3792 case DOUBLE: 3793 case DCOMPLEX: 3794 max = DBL_MAX; min = -DBL_MAX; break; 3795 case LDOUBLE: 3796 case LCOMPLEX: 3797 /* LINTED 248; see floating_error_value. */ 3798 max = LDBL_MAX; min = -max; break; 3799 default: 3800 lint_assert(/*CONSTCOND*/false); 3801 } 3802 if (ov->u.floating > max || ov->u.floating < min) { 3803 lint_assert(nt != LDOUBLE); 3804 const char *ot_name = type_name(gettyp(ov->v_tspec)); 3805 const char *nt_name = type_name(ntp); 3806 if (is_integer(nt)) 3807 goto after_warning; 3808 if (op == FARG) 3809 /* conversion of '%s' to '%s' is out of range, ... */ 3810 warning(295, ot_name, nt_name, arg); 3811 else 3812 /* conversion of '%s' to '%s' is out of range */ 3813 warning(119, ot_name, nt_name); 3814 after_warning: 3815 ov->u.floating = ov->u.floating > 0 ? max : min; 3816 } 3817 3818 if (nt == FLOAT || nt == FCOMPLEX) 3819 nv->u.floating = (float)ov->u.floating; 3820 else if (nt == DOUBLE || nt == DCOMPLEX) 3821 nv->u.floating = (double)ov->u.floating; 3822 else if (nt == LDOUBLE || nt == LCOMPLEX) 3823 nv->u.floating = ov->u.floating; 3824 else 3825 nv->u.integer = (int64_t)ov->u.floating; 3826 } 3827 3828 static bool 3829 convert_constant_to_floating(tspec_t nt, val_t *nv, 3830 tspec_t ot, const val_t *v) 3831 { 3832 if (nt == FLOAT) { 3833 nv->u.floating = (ot == PTR || is_uinteger(ot)) ? 3834 (float)(uint64_t)v->u.integer : (float)v->u.integer; 3835 } else if (nt == DOUBLE) { 3836 nv->u.floating = (ot == PTR || is_uinteger(ot)) ? 3837 (double)(uint64_t)v->u.integer : (double)v->u.integer; 3838 } else if (nt == LDOUBLE) { 3839 nv->u.floating = (ot == PTR || is_uinteger(ot)) 3840 ? (long double)(uint64_t)v->u.integer 3841 : (long double)v->u.integer; 3842 } else 3843 return false; 3844 return true; 3845 } 3846 3847 /* 3848 * Print a warning if bits which were set are lost due to the conversion. 3849 * This can happen with operator ORASS only. 3850 */ 3851 static void 3852 convert_constant_check_range_bitor(size_t nsz, size_t osz, const val_t *v, 3853 uint64_t xmask, op_t op) 3854 { 3855 if (nsz < osz && (v->u.integer & xmask) != 0) 3856 /* constant truncated by conversion, op '%s' */ 3857 warning(306, op_name(op)); 3858 } 3859 3860 static void 3861 convert_constant_check_range_bitand(size_t nsz, size_t osz, 3862 uint64_t xmask, const val_t *nv, 3863 tspec_t ot, const val_t *v, 3864 const type_t *tp, op_t op) 3865 { 3866 if (nsz > osz && 3867 (nv->u.integer & bit((unsigned int)(osz - 1))) != 0 && 3868 (nv->u.integer & xmask) != xmask) { 3869 /* extra bits set to 0 in conversion of '%s' to '%s', ... */ 3870 warning(309, type_name(gettyp(ot)), 3871 type_name(tp), op_name(op)); 3872 } else if (nsz < osz && 3873 (v->u.integer & xmask) != xmask && 3874 (v->u.integer & xmask) != 0) 3875 /* constant truncated by conversion, op '%s' */ 3876 warning(306, op_name(op)); 3877 } 3878 3879 static void 3880 convert_constant_check_range_signed(op_t op, int arg, 3881 const type_t *ntp, int64_t ov) 3882 { 3883 if (op == ASSIGN) 3884 /* assignment of negative constant %lld to unsigned ... */ 3885 warning(164, (long long)ov, type_name(ntp)); 3886 else if (op == INIT) 3887 /* initialization of unsigned type '%s' with negative ... */ 3888 warning(221, type_name(ntp), (long long)ov); 3889 else if (op == FARG) 3890 /* conversion of negative constant %lld to unsigned ... */ 3891 warning(296, (long long)ov, type_name(ntp), arg); 3892 else if (modtab[op].m_comparison) { 3893 /* handled by check_integer_comparison() */ 3894 } else 3895 /* conversion of negative constant %lld to unsigned ... */ 3896 warning(222, (long long)ov, type_name(ntp)); 3897 } 3898 3899 /* 3900 * Loss of significant bit(s). All truncated bits of unsigned types or all 3901 * truncated bits plus the msb of the target for signed types are considered 3902 * to be significant bits. Loss of significant bits means that at least one 3903 * of the bits was set in an unsigned type or that at least one but not all 3904 * of the bits was set in a signed type. Loss of significant bits means that 3905 * it is not possible, also not with necessary casts, to convert back to the 3906 * original type. An example for a necessary cast is: 3907 * char c; int i; c = 128; 3908 * i = c; ** yields -128 ** 3909 * i = (unsigned char)c; ** yields 128 ** 3910 */ 3911 static void 3912 warn_constant_check_range_truncated(op_t op, int arg, const type_t *tp, 3913 tspec_t ot) 3914 { 3915 if (op == ASSIGN && tp->t_bitfield) 3916 /* precision lost in bit-field assignment */ 3917 warning(166); 3918 else if (op == ASSIGN) 3919 /* constant truncated by assignment */ 3920 warning(165); 3921 else if (op == INIT && tp->t_bitfield) 3922 /* bit-field initializer does not fit */ 3923 warning(180); 3924 else if (op == INIT) 3925 /* initializer does not fit */ 3926 warning(178); 3927 else if (op == CASE) 3928 /* case label affected by conversion */ 3929 warning(196); 3930 else if (op == FARG) 3931 /* conversion of '%s' to '%s' is out of range, arg #%d */ 3932 warning(295, type_name(gettyp(ot)), type_name(tp), arg); 3933 else 3934 /* conversion of '%s' to '%s' is out of range */ 3935 warning(119, type_name(gettyp(ot)), type_name(tp)); 3936 } 3937 3938 static void 3939 warn_constant_check_range_loss(op_t op, int arg, const type_t *tp, 3940 tspec_t ot) 3941 { 3942 if (op == ASSIGN && tp->t_bitfield) 3943 /* precision lost in bit-field assignment */ 3944 warning(166); 3945 else if (op == INIT && tp->t_bitfield) 3946 /* bit-field initializer out of range */ 3947 warning(11); 3948 else if (op == CASE) 3949 /* case label affected by conversion */ 3950 warning(196); 3951 else if (op == FARG) 3952 /* conversion of '%s' to '%s' is out of range, arg #%d */ 3953 warning(295, type_name(gettyp(ot)), type_name(tp), arg); 3954 else 3955 /* conversion of '%s' to '%s' is out of range */ 3956 warning(119, type_name(gettyp(ot)), type_name(tp)); 3957 } 3958 3959 static void 3960 convert_constant_check_range(tspec_t ot, const type_t *tp, tspec_t nt, 3961 op_t op, int arg, const val_t *v, val_t *nv) 3962 { 3963 unsigned int obitsz, nbitsz; 3964 uint64_t xmask, xmsk1; 3965 3966 obitsz = size_in_bits(ot); 3967 nbitsz = tp->t_bitfield ? tp->t_bit_field_width : size_in_bits(nt); 3968 xmask = value_bits(nbitsz) ^ value_bits(obitsz); 3969 xmsk1 = value_bits(nbitsz) ^ value_bits(obitsz - 1); 3970 if (op == ORASS || op == BITOR || op == BITXOR) { 3971 convert_constant_check_range_bitor( 3972 nbitsz, obitsz, v, xmask, op); 3973 } else if (op == ANDASS || op == BITAND) { 3974 convert_constant_check_range_bitand( 3975 nbitsz, obitsz, xmask, nv, ot, v, tp, op); 3976 } else if (nt != PTR && is_uinteger(nt) && 3977 ot != PTR && !is_uinteger(ot) && 3978 v->u.integer < 0) 3979 convert_constant_check_range_signed(op, arg, 3980 tp, v->u.integer); 3981 else if (nv->u.integer != v->u.integer && nbitsz <= obitsz && 3982 (v->u.integer & xmask) != 0 && 3983 (is_uinteger(ot) || (v->u.integer & xmsk1) != xmsk1)) 3984 warn_constant_check_range_truncated(op, arg, tp, ot); 3985 else if (nv->u.integer != v->u.integer) 3986 warn_constant_check_range_loss(op, arg, tp, ot); 3987 } 3988 3989 /* Converts a typed constant to a constant of another type. */ 3990 void 3991 convert_constant(op_t op, int arg, const type_t *ntp, val_t *nv, val_t *ov) 3992 { 3993 /* 3994 * TODO: make 'ov' const; the name of this function does not suggest 3995 * that it modifies 'ov'. 3996 */ 3997 tspec_t ot = ov->v_tspec; 3998 tspec_t nt = nv->v_tspec = ntp->t_tspec; 3999 bool range_check = false; 4000 4001 if (nt == BOOL) { /* C99 6.3.1.2 */ 4002 nv->v_unsigned_since_c90 = false; 4003 nv->u.integer = is_nonzero_val(ov) ? 1 : 0; 4004 return; 4005 } 4006 4007 if (ot == FLOAT || ot == DOUBLE || ot == LDOUBLE) 4008 convert_constant_from_floating(op, arg, ntp, nt, nv, ov); 4009 else if (!convert_constant_to_floating(nt, nv, ot, ov)) { 4010 range_check = true; /* Check for lost precision. */ 4011 nv->u.integer = ov->u.integer; 4012 } 4013 4014 if (allow_trad && allow_c90 && ov->v_unsigned_since_c90 && 4015 (is_floating(nt) || ( 4016 (is_integer(nt) && !is_uinteger(nt) && 4017 portable_rank_cmp(nt, ot) > 0)))) { 4018 /* C90 treats constant as unsigned */ 4019 warning(157); 4020 ov->v_unsigned_since_c90 = false; 4021 } 4022 4023 if (is_integer(nt)) { 4024 unsigned int size = ntp->t_bitfield 4025 ? ntp->t_bit_field_width : size_in_bits(nt); 4026 nv->u.integer = convert_integer(nv->u.integer, nt, size); 4027 } 4028 4029 if (range_check && op != CVT) 4030 convert_constant_check_range(ot, ntp, nt, op, arg, ov, nv); 4031 } 4032 4033 tnode_t * 4034 build_sizeof(const type_t *tp) 4035 { 4036 unsigned int size_in_bytes = type_size_in_bits(tp) / CHAR_SIZE; 4037 tnode_t *tn = build_integer_constant(SIZEOF_TSPEC, size_in_bytes); 4038 tn->tn_system_dependent = true; 4039 debug_step("build_sizeof '%s' = %u", type_name(tp), size_in_bytes); 4040 return tn; 4041 } 4042 4043 tnode_t * 4044 build_offsetof(const type_t *tp, designation dn) 4045 { 4046 unsigned int offset_in_bits = 0; 4047 4048 if (!is_struct_or_union(tp->t_tspec)) { 4049 /* unacceptable operand of '%s' */ 4050 error(111, "offsetof"); 4051 goto proceed; 4052 } 4053 for (size_t i = 0; i < dn.dn_len; i++) { 4054 const designator *dr = dn.dn_items + i; 4055 if (dr->dr_kind == DK_SUBSCRIPT) { 4056 if (tp->t_tspec != ARRAY) 4057 goto proceed; /* silent error */ 4058 tp = tp->t_subt; 4059 offset_in_bits += (unsigned) dr->dr_subscript 4060 * type_size_in_bits(tp); 4061 } else { 4062 if (!is_struct_or_union(tp->t_tspec)) 4063 goto proceed; /* silent error */ 4064 const char *name = dr->dr_member->s_name; 4065 sym_t *mem = find_member(tp->u.sou, name); 4066 if (mem == NULL) { 4067 /* type '%s' does not have member '%s' */ 4068 error(101, name, type_name(tp)); 4069 goto proceed; 4070 } 4071 tp = mem->s_type; 4072 offset_in_bits += mem->u.s_member.sm_offset_in_bits; 4073 } 4074 } 4075 free(dn.dn_items); 4076 4077 proceed:; 4078 unsigned int offset_in_bytes = offset_in_bits / CHAR_SIZE; 4079 tnode_t *tn = build_integer_constant(SIZEOF_TSPEC, offset_in_bytes); 4080 tn->tn_system_dependent = true; 4081 return tn; 4082 } 4083 4084 unsigned int 4085 type_size_in_bits(const type_t *tp) 4086 { 4087 4088 unsigned int elem = 1; 4089 bool flex = false; 4090 lint_assert(tp != NULL); 4091 while (tp->t_tspec == ARRAY) { 4092 flex = true; /* allow c99 flex arrays [] [0] */ 4093 elem *= tp->u.dimension; 4094 tp = tp->t_subt; 4095 } 4096 if (elem == 0 && !flex) { 4097 /* cannot take size/alignment of incomplete type */ 4098 error(143); 4099 elem = 1; 4100 } 4101 4102 unsigned int elsz; 4103 switch (tp->t_tspec) { 4104 case VOID: 4105 /* cannot take size/alignment of void */ 4106 error(146); 4107 elsz = 1; 4108 break; 4109 case FUNC: 4110 /* cannot take size/alignment of function type '%s' */ 4111 error(144, type_name(tp)); 4112 elsz = 1; 4113 break; 4114 case STRUCT: 4115 case UNION: 4116 if (is_incomplete(tp)) { 4117 /* cannot take size/alignment of incomplete type */ 4118 error(143); 4119 elsz = 1; 4120 } else 4121 elsz = tp->u.sou->sou_size_in_bits; 4122 break; 4123 case ENUM: 4124 if (is_incomplete(tp)) { 4125 /* cannot take size/alignment of incomplete type */ 4126 warning(143); 4127 } 4128 /* FALLTHROUGH */ 4129 default: 4130 if (tp->t_bitfield) 4131 /* cannot take size/alignment of bit-field */ 4132 error(145); 4133 elsz = size_in_bits(tp->t_tspec); 4134 lint_assert(elsz > 0); 4135 break; 4136 } 4137 4138 return elem * elsz; 4139 } 4140 4141 /* C11 6.5.3.4, GCC */ 4142 tnode_t * 4143 build_alignof(const type_t *tp) 4144 { 4145 if (tp->t_tspec == FUNC) { 4146 /* cannot take size/alignment of function type '%s' */ 4147 error(144, type_name(tp)); 4148 return NULL; 4149 } 4150 if (tp->t_tspec == VOID) { 4151 /* cannot take size/alignment of void */ 4152 error(146); 4153 return NULL; 4154 } 4155 if (is_incomplete(tp)) { 4156 /* cannot take size/alignment of incomplete type */ 4157 error(143); 4158 return NULL; 4159 } 4160 if (tp->t_bitfield) { 4161 /* cannot take size/alignment of bit-field */ 4162 error(145); 4163 return NULL; 4164 } 4165 return build_integer_constant(SIZEOF_TSPEC, (int64_t)alignment(tp)); 4166 } 4167 4168 static tnode_t * 4169 cast_to_union(tnode_t *otn, bool sys, type_t *ntp) 4170 { 4171 4172 if (!allow_gcc) { 4173 /* union cast is a GCC extension */ 4174 error(328); 4175 return NULL; 4176 } 4177 4178 for (const sym_t *m = ntp->u.sou->sou_first_member; 4179 m != NULL; m = m->s_next) { 4180 if (types_compatible(m->s_type, otn->tn_type, 4181 false, false, NULL)) { 4182 tnode_t *ntn = build_op(CVT, sys, ntp, otn, NULL); 4183 ntn->tn_cast = true; 4184 return ntn; 4185 } 4186 } 4187 4188 /* type '%s' is not a member of '%s' */ 4189 error(329, type_name(otn->tn_type), type_name(ntp)); 4190 return NULL; 4191 } 4192 4193 // In GCC mode, allow 'nullptr + offset' as a constant expression. 4194 static tnode_t * 4195 null_pointer_offset(tnode_t *tn) 4196 { 4197 uint64_t off = 0; 4198 const tnode_t *n = tn; 4199 while ((n->tn_op == PLUS || n->tn_op == MINUS) 4200 && is_integer(n->u.ops.right->tn_type->t_tspec)) { 4201 off += (uint64_t)n->u.ops.right->u.value.u.integer; 4202 n = n->u.ops.left; 4203 } 4204 if (n->tn_type->t_tspec == PTR 4205 && n->tn_op == ADDR 4206 && n->u.ops.left->tn_op == INDIR 4207 && n->u.ops.left->u.ops.left->tn_op == CON 4208 && n->u.ops.left->u.ops.left->tn_type->t_tspec == PTR) { 4209 off += (uint64_t)n->u.ops.left->u.ops.left->u.value.u.integer; 4210 return build_integer_constant(SIZEOF_TSPEC, (int64_t)off); 4211 } 4212 return tn; 4213 } 4214 4215 tnode_t * 4216 cast(tnode_t *tn, bool sys, type_t *tp) 4217 { 4218 4219 if (tn == NULL) 4220 return NULL; 4221 4222 tn = cconv(tn); 4223 4224 lint_assert(tp != NULL); 4225 tspec_t nt = tp->t_tspec; 4226 tspec_t ot = tn->tn_type->t_tspec; 4227 4228 if (nt == VOID) { 4229 /* 4230 * C90 6.3.4, C99 6.5.4p2 and C11 6.5.4p2 allow any type to be 4231 * cast to void. The only other allowed casts are from a 4232 * scalar type to a scalar type. 4233 */ 4234 } else if (nt == UNION) 4235 return cast_to_union(tn, sys, tp); 4236 else if (nt == STRUCT || nt == ARRAY || nt == FUNC) { 4237 /* Casting to a struct is an undocumented GCC extension. */ 4238 if (!(allow_gcc && nt == STRUCT)) 4239 goto invalid_cast; 4240 } else if (is_struct_or_union(ot)) 4241 goto invalid_cast; 4242 else if (ot == VOID) { 4243 /* improper cast of void expression */ 4244 error(148); 4245 return NULL; 4246 } else if (is_integer(nt) && is_scalar(ot)) { 4247 tn = null_pointer_offset(tn); 4248 } else if (is_floating(nt) && is_arithmetic(ot)) { 4249 /* ok */ 4250 } else if (nt == PTR && is_integer(ot)) { 4251 /* ok */ 4252 } else if (nt == PTR && ot == PTR) { 4253 if (!tp->t_subt->t_const && tn->tn_type->t_subt->t_const) { 4254 if (hflag) 4255 /* cast discards 'const' from type '%s' */ 4256 warning(275, type_name(tn->tn_type)); 4257 } 4258 } else 4259 goto invalid_cast; 4260 4261 if (any_query_enabled 4262 && types_compatible(tp, tn->tn_type, false, false, NULL)) 4263 /* no-op cast from '%s' to '%s' */ 4264 query_message(6, type_name(tn->tn_type), type_name(tp)); 4265 4266 tn = convert(CVT, 0, tp, tn); 4267 tn->tn_cast = true; 4268 tn->tn_sys = sys; 4269 4270 return tn; 4271 4272 invalid_cast: 4273 /* invalid cast from '%s' to '%s' */ 4274 error(147, type_name(tn->tn_type), type_name(tp)); 4275 return NULL; 4276 } 4277 4278 void 4279 add_function_argument(function_call *call, tnode_t *arg) 4280 { 4281 /* 4282 * If there was a serious error in the expression for the argument, 4283 * create a dummy argument so the positions of the remaining arguments 4284 * will not change. 4285 */ 4286 if (arg == NULL) 4287 arg = build_integer_constant(INT, 0); 4288 4289 if (call->args_len >= call->args_cap) { 4290 call->args_cap += 8; 4291 tnode_t **new_args = expr_zero_alloc( 4292 call->args_cap * sizeof(*call->args), "tnode*[]"); 4293 if (call->args_len > 0) 4294 memcpy(new_args, call->args, 4295 call->args_len * sizeof(*call->args)); 4296 call->args = new_args; 4297 } 4298 call->args[call->args_len++] = arg; 4299 } 4300 4301 /* 4302 * Compare the type of an argument with the corresponding type of a 4303 * prototype parameter. If it is a valid combination, but both types 4304 * are not the same, insert a conversion to convert the argument into 4305 * the type of the parameter. 4306 */ 4307 static tnode_t * 4308 check_prototype_argument( 4309 int n, /* pos of arg */ 4310 type_t *tp, /* expected type (from prototype) */ 4311 tnode_t *tn) /* argument */ 4312 { 4313 tnode_t *ln = xcalloc(1, sizeof(*ln)); 4314 ln->tn_type = expr_unqualified_type(tp); 4315 ln->tn_lvalue = true; 4316 if (typeok(FARG, n, ln, tn)) { 4317 bool dowarn; 4318 if (!types_compatible(tp, tn->tn_type, 4319 true, false, (dowarn = false, &dowarn)) || dowarn) 4320 tn = convert(FARG, n, tp, tn); 4321 } 4322 free(ln); 4323 return tn; 4324 } 4325 4326 /* 4327 * Check types of all function arguments and insert conversions, 4328 * if necessary. 4329 */ 4330 static void 4331 check_function_arguments(const function_call *call) 4332 { 4333 type_t *ftp = call->func->tn_type->t_subt; 4334 4335 /* get # of parameters in the prototype */ 4336 int npar = 0; 4337 for (const sym_t *p = ftp->u.params; p != NULL; p = p->s_next) 4338 npar++; 4339 4340 int narg = (int)call->args_len; 4341 4342 const sym_t *param = ftp->u.params; 4343 if (ftp->t_proto && npar != narg && !(ftp->t_vararg && npar < narg)) { 4344 /* argument mismatch: %d %s passed, %d expected */ 4345 error(150, narg, narg != 1 ? "arguments" : "argument", npar); 4346 param = NULL; 4347 } 4348 4349 for (int i = 0; i < narg; i++) { 4350 tnode_t *arg = call->args[i]; 4351 4352 /* some things which are always not allowed */ 4353 tspec_t at = arg->tn_type->t_tspec; 4354 if (at == VOID) { 4355 /* void expressions may not be arguments, arg #%d */ 4356 error(151, i + 1); 4357 return; 4358 } 4359 if (is_struct_or_union(at) && is_incomplete(arg->tn_type)) { 4360 /* argument cannot have unknown size, arg #%d */ 4361 error(152, i + 1); 4362 return; 4363 } 4364 if (is_integer(at) && 4365 arg->tn_type->t_is_enum && 4366 is_incomplete(arg->tn_type)) { 4367 /* argument cannot have unknown size, arg #%d */ 4368 warning(152, i + 1); 4369 } 4370 4371 arg = cconv(arg); 4372 call->args[i] = arg; 4373 4374 arg = param != NULL 4375 ? check_prototype_argument(i + 1, param->s_type, arg) 4376 : promote(NOOP, true, arg); 4377 call->args[i] = arg; 4378 4379 if (param != NULL) 4380 param = param->s_next; 4381 } 4382 } 4383 4384 tnode_t * 4385 build_function_call(tnode_t *func, bool sys, function_call *call) 4386 { 4387 4388 if (func == NULL) 4389 return NULL; 4390 4391 call->func = func; 4392 check_ctype_function_call(call); 4393 4394 func = cconv(func); 4395 call->func = func; 4396 4397 if (func->tn_type->t_tspec != PTR || 4398 func->tn_type->t_subt->t_tspec != FUNC) { 4399 /* cannot call '%s', must be a function */ 4400 error(149, type_name(func->tn_type)); 4401 return NULL; 4402 } 4403 4404 check_function_arguments(call); 4405 4406 tnode_t *ntn = expr_alloc_tnode(); 4407 ntn->tn_op = CALL; 4408 ntn->tn_type = func->tn_type->t_subt->t_subt; 4409 ntn->tn_sys = sys; 4410 ntn->u.call = call; 4411 return ntn; 4412 } 4413 4414 /* 4415 * Return the value of an integral constant expression. 4416 * If the expression is not constant or its type is not an integer 4417 * type, an error message is printed. 4418 */ 4419 val_t * 4420 integer_constant(tnode_t *tn, bool required) 4421 { 4422 4423 if (tn != NULL) 4424 tn = cconv(tn); 4425 if (tn != NULL) 4426 tn = promote(NOOP, false, tn); 4427 4428 val_t *v = xcalloc(1, sizeof(*v)); 4429 4430 if (tn == NULL) { 4431 lint_assert(seen_error); 4432 debug_step("constant node is null; returning 1 instead"); 4433 v->v_tspec = INT; 4434 v->u.integer = 1; 4435 return v; 4436 } 4437 4438 v->v_tspec = tn->tn_type->t_tspec; 4439 4440 if (tn->tn_op == CON) { 4441 lint_assert(tn->tn_type->t_tspec == tn->u.value.v_tspec); 4442 if (is_integer(tn->u.value.v_tspec)) { 4443 v->v_unsigned_since_c90 = 4444 tn->u.value.v_unsigned_since_c90; 4445 v->u.integer = tn->u.value.u.integer; 4446 return v; 4447 } 4448 v->u.integer = (int64_t)tn->u.value.u.floating; 4449 } else 4450 v->u.integer = 1; 4451 4452 if (required) 4453 /* integral constant expression expected */ 4454 error(55); 4455 else 4456 /* variable array dimension is a C99/GCC extension */ 4457 c99ism(318); 4458 4459 if (!is_integer(v->v_tspec)) 4460 v->v_tspec = INT; 4461 4462 return v; 4463 } 4464 4465 static bool 4466 is_constcond_false(const tnode_t *tn, tspec_t t) 4467 { 4468 return (t == BOOL || t == INT) && 4469 tn->tn_op == CON && tn->u.value.u.integer == 0; 4470 } 4471 4472 /* 4473 * Perform some tests on expressions which can't be done in build_binary() 4474 * and functions called by build_binary(). These tests must be done here 4475 * because we need some information about the context in which the operations 4476 * are performed. 4477 * After all tests are performed and dofreeblk is true, expr() frees the 4478 * memory which is used for the expression. 4479 */ 4480 void 4481 expr(tnode_t *tn, bool vctx, bool cond, bool dofreeblk, bool is_do_while) 4482 { 4483 4484 if (tn == NULL) { /* in case of errors */ 4485 expr_free_all(); 4486 return; 4487 } 4488 4489 /* expr() is also called in global initializations */ 4490 if (dcs->d_kind != DLK_EXTERN && !is_do_while) 4491 check_statement_reachable(); 4492 4493 check_expr_misc(tn, vctx, cond, !cond, false, false, false); 4494 if (tn->tn_op == ASSIGN && !tn->tn_parenthesized) { 4495 if (hflag && cond) 4496 /* assignment in conditional context */ 4497 warning(159); 4498 } else if (tn->tn_op == CON) { 4499 if (hflag && cond && !suppress_constcond && 4500 !tn->tn_system_dependent && 4501 !(is_do_while && 4502 is_constcond_false(tn, tn->tn_type->t_tspec))) 4503 /* constant in conditional context */ 4504 warning(161); 4505 } 4506 if (!modtab[tn->tn_op].m_has_side_effect) { 4507 /* 4508 * for left operands of COMMA this warning is already printed 4509 */ 4510 if (tn->tn_op != COMMA && !vctx && !cond) 4511 check_null_effect(tn); 4512 } 4513 debug_node(tn); 4514 4515 if (dofreeblk) 4516 expr_free_all(); 4517 } 4518 4519 /* If the expression has the form '*(arr + idx)', check the array index. */ 4520 static void 4521 check_array_index(const tnode_t *indir, bool taking_address) 4522 { 4523 const tnode_t *plus, *arr, *idx; 4524 4525 if (indir->tn_op == INDIR 4526 && (plus = indir->u.ops.left, plus->tn_op == PLUS) 4527 && plus->u.ops.left->tn_op == ADDR 4528 && (arr = plus->u.ops.left->u.ops.left, true) 4529 && (arr->tn_op == STRING || arr->tn_op == NAME) 4530 && arr->tn_type->t_tspec == ARRAY 4531 && (idx = plus->u.ops.right, idx->tn_op == CON) 4532 && (!is_incomplete(arr->tn_type) || idx->u.value.u.integer < 0)) 4533 goto proceed; 4534 return; 4535 4536 proceed:; 4537 int elsz = length_in_bits(arr->tn_type->t_subt, NULL); 4538 if (elsz == 0) 4539 return; 4540 elsz /= CHAR_SIZE; 4541 4542 /* Change the unit of the index from bytes to element size. */ 4543 int64_t con = is_uinteger(idx->tn_type->t_tspec) 4544 ? (int64_t)((uint64_t)idx->u.value.u.integer / elsz) 4545 : idx->u.value.u.integer / elsz; 4546 4547 int dim = arr->tn_type->u.dimension + (taking_address ? 1 : 0); 4548 4549 if (!is_uinteger(idx->tn_type->t_tspec) && con < 0) 4550 /* array subscript %jd cannot be negative */ 4551 warning(167, (intmax_t)con); 4552 else if (dim > 0 && (uint64_t)con >= (uint64_t)dim) 4553 /* array subscript %ju cannot be > %d */ 4554 warning(168, (uintmax_t)con, dim - 1); 4555 } 4556 4557 static void 4558 check_expr_addr(const tnode_t *ln, bool szof, bool fcall) 4559 { 4560 /* XXX: Taking warn_about_unreachable into account here feels wrong. */ 4561 if (ln->tn_op == NAME && (reached || !warn_about_unreachable)) { 4562 if (!szof) 4563 mark_as_set(ln->u.sym); 4564 mark_as_used(ln->u.sym, fcall, szof); 4565 } 4566 check_array_index(ln, true); 4567 } 4568 4569 /* 4570 * If there is an asm statement in one of the compound statements around, 4571 * there may be other side effects, so don't warn. 4572 */ 4573 static bool 4574 is_asm_around(void) 4575 { 4576 for (decl_level *dl = dcs; dl != NULL; dl = dl->d_enclosing) 4577 if (dl->d_asm) 4578 return true; 4579 return false; 4580 } 4581 4582 static void 4583 check_expr_side_effect(const tnode_t *ln, bool szof) 4584 { 4585 4586 /* XXX: Taking warn_about_unreachable into account here feels wrong. */ 4587 if (ln->tn_op == NAME && (reached || !warn_about_unreachable)) { 4588 scl_t sc = ln->u.sym->s_scl; 4589 if (sc != EXTERN && sc != STATIC && 4590 !ln->u.sym->s_set && !szof && !is_asm_around()) { 4591 /* '%s' may be used before set */ 4592 warning(158, ln->u.sym->s_name); 4593 mark_as_set(ln->u.sym); 4594 } 4595 mark_as_used(ln->u.sym, false, false); 4596 } 4597 } 4598 4599 static void 4600 check_expr_assign(const tnode_t *ln, bool szof) 4601 { 4602 /* XXX: Taking warn_about_unreachable into account here feels wrong. */ 4603 if (ln->tn_op == NAME && !szof && (reached || !warn_about_unreachable)) { 4604 mark_as_set(ln->u.sym); 4605 if (ln->u.sym->s_scl == EXTERN) 4606 outusg(ln->u.sym); 4607 } 4608 check_array_index(ln, false); 4609 } 4610 4611 static void 4612 check_expr_call(const tnode_t *tn, const tnode_t *ln, 4613 bool szof, bool vctx, bool cond, bool retval_discarded) 4614 { 4615 lint_assert(ln->tn_op == ADDR); 4616 lint_assert(ln->u.ops.left->tn_op == NAME); 4617 if (!szof && !is_compiler_builtin(ln->u.ops.left->u.sym->s_name)) 4618 outcall(tn, vctx || cond, retval_discarded); 4619 4620 const function_call *call = tn->u.call; 4621 if (call->args_len == 4 || call->args_len == 5) 4622 check_snprintb(call); 4623 } 4624 4625 static void 4626 check_expr_op(op_t op, const tnode_t *ln, bool szof, bool fcall, bool eqwarn) 4627 { 4628 switch (op) { 4629 case ADDR: 4630 check_expr_addr(ln, szof, fcall); 4631 break; 4632 case LOAD: 4633 check_array_index(ln, false); 4634 /* FALLTHROUGH */ 4635 case INCBEF: 4636 case DECBEF: 4637 case INCAFT: 4638 case DECAFT: 4639 case ADDASS: 4640 case SUBASS: 4641 case MULASS: 4642 case DIVASS: 4643 case MODASS: 4644 case ANDASS: 4645 case ORASS: 4646 case XORASS: 4647 case SHLASS: 4648 case SHRASS: 4649 case REAL: 4650 case IMAG: 4651 check_expr_side_effect(ln, szof); 4652 break; 4653 case ASSIGN: 4654 check_expr_assign(ln, szof); 4655 break; 4656 case EQ: 4657 if (hflag && eqwarn) 4658 /* operator '==' found where '=' was expected */ 4659 warning(160); 4660 break; 4661 default: 4662 break; 4663 } 4664 } 4665 4666 /* 4667 * vctx ??? 4668 * cond whether the expression is a condition that 4669 * will be compared with 0 4670 * eqwarn whether the operator '==' might be a 4671 * misspelled '=' 4672 * fcall whether the expression is a function call 4673 * retval_discarded whether the return value of a function call 4674 * is discarded; such calls will be analyzed by 4675 * lint2 in messages 4, 8 and 9 4676 * szof whether the expression is part of a sizeof 4677 * expression, which means that its value is 4678 * discarded since only the type is relevant 4679 */ 4680 void 4681 check_expr_misc(const tnode_t *tn, bool vctx, bool cond, 4682 bool eqwarn, bool fcall, bool retval_discarded, bool szof) 4683 { 4684 4685 if (tn == NULL) 4686 return; 4687 op_t op = tn->tn_op; 4688 if (op == NAME || op == CON || op == STRING) 4689 return; 4690 bool is_direct = op == CALL 4691 && tn->u.call->func->tn_op == ADDR 4692 && tn->u.call->func->u.ops.left->tn_op == NAME; 4693 if (op == CALL) { 4694 const function_call *call = tn->u.call; 4695 if (is_direct) 4696 check_expr_call(tn, call->func, 4697 szof, vctx, cond, retval_discarded); 4698 bool discard = op == CVT && tn->tn_type->t_tspec == VOID; 4699 check_expr_misc(call->func, false, false, false, is_direct, 4700 discard, szof); 4701 for (size_t i = 0, n = call->args_len; i < n; i++) 4702 check_expr_misc(call->args[i], 4703 true, false, false, false, false, szof); 4704 return; 4705 } 4706 4707 lint_assert(has_operands(tn)); 4708 tnode_t *ln = tn->u.ops.left; 4709 tnode_t *rn = tn->u.ops.right; 4710 check_expr_op(op, ln, szof, fcall, eqwarn); 4711 4712 const mod_t *mp = &modtab[op]; 4713 bool cvctx = mp->m_value_context; 4714 bool ccond = mp->m_compares_with_zero; 4715 bool eq = mp->m_warn_if_operand_eq && 4716 !ln->tn_parenthesized && 4717 rn != NULL && !rn->tn_parenthesized; 4718 4719 /* 4720 * Values of operands of ':' are not used if the type of at least 4721 * one of the operands (for GCC compatibility) is 'void'. 4722 * 4723 * XXX test/value context of QUEST should probably be used as 4724 * context for both operands of COLON. 4725 */ 4726 if (op == COLON && tn->tn_type->t_tspec == VOID) 4727 cvctx = ccond = false; 4728 bool discard = op == CVT && tn->tn_type->t_tspec == VOID; 4729 check_expr_misc(ln, cvctx, ccond, eq, is_direct, discard, szof); 4730 4731 switch (op) { 4732 case LOGAND: 4733 case LOGOR: 4734 check_expr_misc(rn, false, true, eq, false, false, szof); 4735 break; 4736 case COLON: 4737 check_expr_misc(rn, cvctx, ccond, eq, false, false, szof); 4738 break; 4739 case COMMA: 4740 check_expr_misc(rn, vctx, cond, false, false, false, szof); 4741 break; 4742 default: 4743 if (mp->m_binary) 4744 check_expr_misc(rn, true, false, eq, false, false, 4745 szof); 4746 break; 4747 } 4748 } 4749 4750 /* 4751 * Return whether the expression can be used for static initialization. 4752 * 4753 * Constant initialization expressions must be constant or an address 4754 * of a static object with an optional offset. In the first case, 4755 * the result is returned in *offsp. In the second case, the static 4756 * object is returned in *symp and the offset in *offsp. 4757 * 4758 * The expression can consist of PLUS, MINUS, ADDR, NAME, STRING and 4759 * CON. Type conversions are allowed if they do not change binary 4760 * representation (including width). 4761 * 4762 * C99 6.6 "Constant expressions" 4763 * C99 6.7.8p4 restricts initializers for static storage duration 4764 */ 4765 bool 4766 constant_addr(const tnode_t *tn, const sym_t **symp, ptrdiff_t *offsp) 4767 { 4768 const sym_t *sym; 4769 ptrdiff_t offs1, offs2; 4770 tspec_t t, ot; 4771 4772 switch (tn->tn_op) { 4773 case MINUS: 4774 if (tn->u.ops.right->tn_op == CVT) 4775 return constant_addr(tn->u.ops.right, symp, offsp); 4776 else if (tn->u.ops.right->tn_op != CON) 4777 return false; 4778 /* FALLTHROUGH */ 4779 case PLUS: 4780 offs1 = offs2 = 0; 4781 if (tn->u.ops.left->tn_op == CON) { 4782 offs1 = (ptrdiff_t)tn->u.ops.left->u.value.u.integer; 4783 if (!constant_addr(tn->u.ops.right, &sym, &offs2)) 4784 return false; 4785 } else if (tn->u.ops.right->tn_op == CON) { 4786 offs2 = (ptrdiff_t)tn->u.ops.right->u.value.u.integer; 4787 if (tn->tn_op == MINUS) 4788 offs2 = -offs2; 4789 if (!constant_addr(tn->u.ops.left, &sym, &offs1)) 4790 return false; 4791 } else { 4792 return false; 4793 } 4794 *symp = sym; 4795 *offsp = offs1 + offs2; 4796 return true; 4797 case ADDR: 4798 if (tn->u.ops.left->tn_op == NAME) { 4799 *symp = tn->u.ops.left->u.sym; 4800 *offsp = 0; 4801 return true; 4802 } else { 4803 /* 4804 * If this were the front end of a compiler, we would 4805 * return a label instead of 0, at least if 4806 * 'tn->u.ops.left->tn_op == STRING'. 4807 */ 4808 *symp = NULL; 4809 *offsp = 0; 4810 return true; 4811 } 4812 case CVT: 4813 t = tn->tn_type->t_tspec; 4814 ot = tn->u.ops.left->tn_type->t_tspec; 4815 if ((!is_integer(t) && t != PTR) || 4816 (!is_integer(ot) && ot != PTR)) { 4817 return false; 4818 } 4819 #if 0 4820 /*- 4821 * consider: 4822 * struct foo { 4823 * unsigned char a; 4824 * } f = { 4825 * (unsigned char)(unsigned long) 4826 * (&(((struct foo *)0)->a)) 4827 * }; 4828 * since psize(unsigned long) != psize(unsigned char), 4829 * this fails. 4830 */ 4831 else if (psize(t) != psize(ot)) 4832 return -1; 4833 #endif 4834 return constant_addr(tn->u.ops.left, symp, offsp); 4835 default: 4836 return false; 4837 } 4838 } 4839 4840 /* Append s2 to s1, then free s2. */ 4841 buffer * 4842 cat_strings(buffer *s1, buffer *s2) 4843 { 4844 4845 if ((s1->data != NULL) != (s2->data != NULL)) { 4846 /* cannot concatenate wide and regular string literals */ 4847 error(292); 4848 return s1; 4849 } 4850 4851 if (s1->data != NULL) { 4852 while (s1->len + s2->len + 1 > s1->cap) 4853 s1->cap *= 2; 4854 s1->data = xrealloc(s1->data, s1->cap); 4855 memcpy(s1->data + s1->len, s2->data, s2->len + 1); 4856 free(s2->data); 4857 } 4858 s1->len += s2->len; 4859 free(s2); 4860 4861 return s1; 4862 } 4863 4864 4865 typedef struct stmt_expr { 4866 memory_pool se_mem; 4867 sym_t *se_sym; 4868 struct stmt_expr *se_enclosing; 4869 } stmt_expr; 4870 4871 static stmt_expr *stmt_exprs; 4872 4873 void 4874 begin_statement_expr(void) 4875 { 4876 debug_enter(); 4877 4878 stmt_expr *se = xmalloc(sizeof(*se)); 4879 se->se_mem = expr_save_memory(); 4880 se->se_sym = NULL; 4881 se->se_enclosing = stmt_exprs; 4882 stmt_exprs = se; 4883 } 4884 4885 void 4886 do_statement_expr(tnode_t *tn) 4887 { 4888 block_level--; 4889 mem_block_level--; 4890 stmt_exprs->se_sym = tn != NULL 4891 ? mktempsym(block_dup_type(tn->tn_type)) 4892 : NULL; /* after a syntax error */ 4893 mem_block_level++; 4894 block_level++; 4895 /* '({ ... })' is a GCC extension */ 4896 gnuism(320); 4897 } 4898 4899 tnode_t * 4900 end_statement_expr(void) 4901 { 4902 tnode_t *tn; 4903 4904 stmt_expr *se = stmt_exprs; 4905 if (se->se_sym == NULL) { 4906 tn = NULL; /* after a syntax error */ 4907 goto end; 4908 } 4909 4910 tn = build_name(se->se_sym, false); 4911 (void)expr_save_memory(); /* leak */ 4912 expr_restore_memory(se->se_mem); 4913 stmt_exprs = se->se_enclosing; 4914 free(se); 4915 4916 end: 4917 debug_leave(); 4918 return tn; 4919 } 4920 4921 bool 4922 in_statement_expr(void) 4923 { 4924 return stmt_exprs != NULL; 4925 } 4926
Indexes created Tue Sep 23 02:09:52 GMT 2025