tree.c revision 1.665
1 /* $NetBSD: tree.c,v 1.665 2025/01/01 14:09:28 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 1.665 2025/01/01 14:09:28 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 int64_t 63 s64_min(int64_t a, int64_t b) 64 { 65 return a < b ? a : b; 66 } 67 68 static int64_t 69 s64_max(int64_t a, int64_t b) 70 { 71 return a > b ? a : b; 72 } 73 74 static uint64_t 75 s64_abs(int64_t x) 76 { 77 return x >= 0 ? (uint64_t)x : -(uint64_t)x; 78 } 79 80 static uint64_t 81 u64_max(uint64_t a, uint64_t b) 82 { 83 return a > b ? a : b; 84 } 85 86 static int64_t 87 si_min_value(const type_t *tp) 88 { 89 uint64_t mask = value_bits(size_in_bits(tp->t_tspec)); 90 return -(int64_t)(mask >> 1) - 1; 91 } 92 93 static int64_t 94 si_max_value(const type_t *tp) 95 { 96 uint64_t mask = value_bits(size_in_bits(tp->t_tspec)); 97 return (int64_t)(mask >> 1); 98 } 99 100 static uint64_t 101 ui_max_value(const type_t *tp) 102 { 103 return value_bits(size_in_bits(tp->t_tspec)); 104 } 105 106 static int64_t 107 si_plus_sat(const type_t *tp, int64_t a, int64_t b) 108 { 109 if (a >= 0) { 110 int64_t max = si_max_value(tp); 111 return b <= max - a ? a + b : max; 112 } else { 113 int64_t min = si_min_value(tp); 114 return b >= min - a ? a + b : min; 115 } 116 } 117 118 static uint64_t 119 ui_plus_sat(const type_t *tp, uint64_t a, uint64_t b) 120 { 121 uint64_t max = ui_max_value(tp); 122 return b <= max - a ? a + b : max; 123 } 124 125 static uint64_t 126 u64_fill_right(uint64_t x) 127 { 128 x |= x >> 1; 129 x |= x >> 2; 130 x |= x >> 4; 131 x |= x >> 8; 132 x |= x >> 16; 133 x |= x >> 32; 134 return x; 135 } 136 137 static bool 138 str_ends_with(const char *haystack, const char *needle) 139 { 140 size_t hlen = strlen(haystack); 141 size_t nlen = strlen(needle); 142 143 return nlen <= hlen && 144 memcmp(haystack + hlen - nlen, needle, nlen) == 0; 145 } 146 147 static unsigned 148 width_in_bits(const type_t *tp) 149 { 150 151 lint_assert(is_integer(tp->t_tspec)); 152 return tp->t_bitfield 153 ? tp->t_bit_field_width 154 : size_in_bits(tp->t_tspec); 155 } 156 157 static int 158 portable_rank_cmp(tspec_t t1, tspec_t t2) 159 { 160 const ttab_t *p1 = type_properties(t1), *p2 = type_properties(t2); 161 lint_assert(p1->tt_rank_kind == p2->tt_rank_kind); 162 lint_assert(p1->tt_rank_value > 0); 163 lint_assert(p2->tt_rank_value > 0); 164 return (int)p1->tt_rank_value - (int)p2->tt_rank_value; 165 } 166 167 static bool 168 ic_maybe_signed(const type_t *tp, const integer_constraints *ic) 169 { 170 return !is_uinteger(tp->t_tspec) && ic->bclr >> 63 == 0; 171 } 172 173 static integer_constraints 174 ic_any(const type_t *tp) 175 { 176 integer_constraints c; 177 178 uint64_t vbits = value_bits(width_in_bits(tp)); 179 if (is_uinteger(tp->t_tspec)) { 180 c.smin = INT64_MIN; 181 c.smax = INT64_MAX; 182 c.umin = 0; 183 c.umax = vbits; 184 c.bclr = ~c.umax; 185 } else { 186 c.smin = (int64_t)-1 - (int64_t)(vbits >> 1); 187 c.smax = (int64_t)(vbits >> 1); 188 c.umin = 0; 189 c.umax = UINT64_MAX; 190 c.bclr = 0; 191 } 192 return c; 193 } 194 195 static integer_constraints 196 ic_mult(const type_t *tp, integer_constraints a, integer_constraints b) 197 { 198 integer_constraints c; 199 200 if (ic_maybe_signed(tp, &a) || ic_maybe_signed(tp, &b) 201 || (a.umax > 0 && b.umax > ic_any(tp).umax / a.umax)) 202 return ic_any(tp); 203 204 c.smin = INT64_MIN; 205 c.smax = INT64_MAX; 206 c.umin = a.umin * b.umin; 207 c.umax = a.umax * b.umax; 208 c.bclr = ~u64_fill_right(c.umax); 209 return c; 210 } 211 212 static integer_constraints 213 ic_div(const type_t *tp, integer_constraints a, integer_constraints b) 214 { 215 integer_constraints c; 216 217 if (ic_maybe_signed(tp, &a) || ic_maybe_signed(tp, &b) || b.umin == 0) 218 return ic_any(tp); 219 220 c.smin = INT64_MIN; 221 c.smax = INT64_MAX; 222 c.umin = a.umin / b.umax; 223 c.umax = a.umax / b.umin; 224 c.bclr = ~u64_fill_right(c.umax); 225 return c; 226 } 227 228 static integer_constraints 229 ic_mod_signed(integer_constraints a, integer_constraints b) 230 { 231 integer_constraints c; 232 233 uint64_t max_abs_b = u64_max(s64_abs(b.smin), s64_abs(b.smax)); 234 if (max_abs_b >> 63 != 0 || max_abs_b == 0) 235 return a; 236 c.smin = s64_max(a.smin, -(int64_t)(max_abs_b - 1)); 237 c.smax = s64_min(a.smax, (int64_t)(max_abs_b - 1)); 238 c.umin = 0; 239 c.umax = UINT64_MAX; 240 c.bclr = 0; 241 return c; 242 } 243 244 static integer_constraints 245 ic_mod(const type_t *tp, integer_constraints a, integer_constraints b) 246 { 247 integer_constraints c; 248 249 if (ic_maybe_signed(tp, &a) || ic_maybe_signed(tp, &b)) 250 return ic_mod_signed(a, b); 251 252 c.smin = INT64_MIN; 253 c.smax = INT64_MAX; 254 c.umin = 0; 255 c.umax = b.umax - 1; 256 c.bclr = ~u64_fill_right(c.umax); 257 return c; 258 } 259 260 static integer_constraints 261 ic_plus(const type_t *tp, integer_constraints a, integer_constraints b) 262 { 263 bool maybe_signed = ic_maybe_signed(tp, &a) || ic_maybe_signed(tp, &b); 264 265 integer_constraints c; 266 c.smin = maybe_signed ? si_plus_sat(tp, a.smin, b.smin) : INT64_MIN; 267 c.smax = maybe_signed ? si_plus_sat(tp, a.smax, b.smax) : INT64_MAX; 268 c.umin = maybe_signed ? 0 : ui_plus_sat(tp, a.umin, b.umin); 269 c.umax = maybe_signed ? UINT64_MAX : ui_plus_sat(tp, a.umax, b.umax); 270 c.bclr = ~u64_fill_right(c.umax); 271 return c; 272 } 273 274 static integer_constraints 275 ic_shl(const type_t *tp, integer_constraints a, integer_constraints b) 276 { 277 integer_constraints c; 278 unsigned int amount; 279 280 if (ic_maybe_signed(tp, &a)) 281 return ic_any(tp); 282 283 if (b.smin == b.smax && b.smin >= 0 && b.smin < 64) 284 amount = (unsigned int)b.smin; 285 else if (b.umin == b.umax && b.umin < 64) 286 amount = (unsigned int)b.umin; 287 else 288 return ic_any(tp); 289 290 c.smin = INT64_MIN; 291 c.smax = INT64_MAX; 292 c.umin = 0; 293 c.umax = UINT64_MAX; 294 c.bclr = a.bclr << amount | (((uint64_t)1 << amount) - 1); 295 return c; 296 } 297 298 static integer_constraints 299 ic_shr(const type_t *tp, integer_constraints a, integer_constraints b) 300 { 301 integer_constraints c; 302 unsigned int amount; 303 304 if (ic_maybe_signed(tp, &a)) 305 return ic_any(tp); 306 307 if (b.smin == b.smax && b.smin >= 0 && b.smin < 64) 308 amount = (unsigned int)b.smin; 309 else if (b.umin == b.umax && b.umin < 64) 310 amount = (unsigned int)b.umin; 311 else 312 return ic_any(tp); 313 314 c.smin = INT64_MIN; 315 c.smax = INT64_MAX; 316 c.umin = 0; 317 c.umax = UINT64_MAX; 318 c.bclr = a.bclr >> amount | ~(~(uint64_t)0 >> amount); 319 return c; 320 } 321 322 static integer_constraints 323 ic_bitand(integer_constraints a, integer_constraints b) 324 { 325 integer_constraints c; 326 327 c.smin = INT64_MIN; 328 c.smax = INT64_MAX; 329 c.umin = 0; 330 c.umax = ~(a.bclr | b.bclr); 331 if (c.umax >> 63 == 0) { 332 c.smin = 0; 333 c.smax = (int64_t)c.umax; 334 } 335 c.bclr = a.bclr | b.bclr; 336 return c; 337 } 338 339 static integer_constraints 340 ic_bitor(integer_constraints a, integer_constraints b) 341 { 342 integer_constraints c; 343 344 c.smin = INT64_MIN; 345 c.smax = INT64_MAX; 346 c.umin = 0; 347 c.umax = ~(a.bclr & b.bclr); 348 c.bclr = a.bclr & b.bclr; 349 return c; 350 } 351 352 static integer_constraints 353 ic_quest_colon(integer_constraints a, integer_constraints b) 354 { 355 integer_constraints c; 356 357 c.smin = a.smin < b.smin ? a.smin : b.smin; 358 c.smax = a.smax > b.smax ? a.smax : b.smax; 359 c.umin = a.umin < b.umin ? a.umin : b.umin; 360 c.umax = a.umax > b.umax ? a.umax : b.umax; 361 c.bclr = a.bclr & b.bclr; 362 return c; 363 } 364 365 static integer_constraints 366 ic_con(const type_t *tp, const val_t *v) 367 { 368 integer_constraints c; 369 370 lint_assert(is_integer(tp->t_tspec)); 371 int64_t si = v->u.integer; 372 uint64_t ui = (uint64_t)si; 373 c.smin = si; 374 c.smax = si; 375 c.umin = ui; 376 c.umax = ui; 377 c.bclr = ~ui; 378 return c; 379 } 380 381 static integer_constraints 382 ic_cvt(const type_t *ntp, const type_t *otp, integer_constraints a) 383 { 384 unsigned nw = width_in_bits(ntp); 385 unsigned ow = width_in_bits(otp); 386 bool nu = is_uinteger(ntp->t_tspec); 387 bool ou = is_uinteger(otp->t_tspec); 388 389 if (nw >= ow && nu == ou) 390 return a; 391 if (nw > ow && ou) 392 return a; 393 return ic_any(ntp); 394 } 395 396 static integer_constraints 397 ic_expr(const tnode_t *tn) 398 { 399 integer_constraints lc, rc; 400 401 lint_assert(is_integer(tn->tn_type->t_tspec)); 402 403 switch (tn->tn_op) { 404 case MULT: 405 lc = ic_expr(before_conversion(tn->u.ops.left)); 406 rc = ic_expr(before_conversion(tn->u.ops.right)); 407 return ic_mult(tn->tn_type, lc, rc); 408 case DIV: 409 lc = ic_expr(before_conversion(tn->u.ops.left)); 410 rc = ic_expr(before_conversion(tn->u.ops.right)); 411 return ic_div(tn->tn_type, lc, rc); 412 case MOD: 413 lc = ic_expr(before_conversion(tn->u.ops.left)); 414 rc = ic_expr(before_conversion(tn->u.ops.right)); 415 return ic_mod(tn->tn_type, lc, rc); 416 case PLUS: 417 lc = ic_expr(before_conversion(tn->u.ops.left)); 418 rc = ic_expr(before_conversion(tn->u.ops.right)); 419 return ic_plus(tn->tn_type, lc, rc); 420 case SHL: 421 lc = ic_expr(tn->u.ops.left); 422 rc = ic_expr(tn->u.ops.right); 423 return ic_shl(tn->tn_type, lc, rc); 424 case SHR: 425 lc = ic_expr(tn->u.ops.left); 426 rc = ic_expr(tn->u.ops.right); 427 return ic_shr(tn->tn_type, lc, rc); 428 case BITAND: 429 lc = ic_expr(tn->u.ops.left); 430 rc = ic_expr(tn->u.ops.right); 431 return ic_bitand(lc, rc); 432 case BITOR: 433 lc = ic_expr(tn->u.ops.left); 434 rc = ic_expr(tn->u.ops.right); 435 return ic_bitor(lc, rc); 436 case QUEST: 437 lc = ic_expr(tn->u.ops.right->u.ops.left); 438 rc = ic_expr(tn->u.ops.right->u.ops.right); 439 return ic_quest_colon(lc, rc); 440 case CON: 441 return ic_con(tn->tn_type, &tn->u.value); 442 case CVT: 443 if (!is_integer(tn->u.ops.left->tn_type->t_tspec)) 444 return ic_any(tn->tn_type); 445 lc = ic_expr(tn->u.ops.left); 446 return ic_cvt(tn->tn_type, tn->u.ops.left->tn_type, lc); 447 default: 448 return ic_any(tn->tn_type); 449 } 450 } 451 452 uint64_t 453 possible_bits(const tnode_t *tn) 454 { 455 return ~ic_expr(tn).bclr; 456 } 457 458 bool 459 attributes_contain(const attribute_list *attrs, const char *str) 460 { 461 for (size_t i = 0, n = attrs->len; i < n; i++) { 462 const attribute *attr = attrs->attrs + i; 463 if (attr->prefix == NULL && strcmp(attr->name, str) == 0) 464 return true; 465 } 466 return false; 467 } 468 469 /* Build 'pointer to tp', 'array of tp' or 'function returning tp'. */ 470 type_t * 471 block_derive_type(type_t *tp, tspec_t t) 472 { 473 474 type_t *tp2 = block_zero_alloc(sizeof(*tp2), "type"); 475 tp2->t_tspec = t; 476 tp2->t_subt = tp; 477 return tp2; 478 } 479 480 /* 481 * Derive 'pointer to tp' or 'function returning tp'. 482 * The memory is freed at the end of the current expression. 483 */ 484 type_t * 485 expr_derive_type(type_t *tp, tspec_t t) 486 { 487 488 type_t *tp2 = expr_zero_alloc(sizeof(*tp2), "type"); 489 tp2->t_tspec = t; 490 tp2->t_subt = tp; 491 return tp2; 492 } 493 494 /* Create an expression from a unary or binary operator and its operands. */ 495 static tnode_t * 496 build_op(op_t op, bool sys, type_t *type, tnode_t *ln, tnode_t *rn) 497 { 498 499 tnode_t *ntn = expr_alloc_tnode(); 500 ntn->tn_op = op; 501 ntn->tn_type = type; 502 ntn->tn_sys = sys; 503 ntn->u.ops.left = ln; 504 ntn->u.ops.right = rn; 505 506 if (op == INDIR || op == FSEL) { 507 lint_assert(ln->tn_type->t_tspec == PTR); 508 tspec_t t = ln->tn_type->t_subt->t_tspec; 509 ntn->tn_lvalue = t != FUNC && t != VOID; 510 } 511 512 return ntn; 513 } 514 515 tnode_t * 516 build_constant(type_t *tp, val_t *v) 517 { 518 519 tnode_t *n = expr_alloc_tnode(); 520 n->tn_op = CON; 521 n->tn_type = tp; 522 n->u.value = *v; 523 n->u.value.v_tspec = tp->t_tspec; 524 free(v); 525 return n; 526 } 527 528 static tnode_t * 529 build_integer_constant(tspec_t t, int64_t si) 530 { 531 532 tnode_t *n = expr_alloc_tnode(); 533 n->tn_op = CON; 534 n->tn_type = gettyp(t); 535 n->u.value.v_tspec = t; 536 n->u.value.v_unsigned_since_c90 = false; 537 n->u.value.v_char_constant = false; 538 n->u.value.u.integer = si; 539 return n; 540 } 541 542 static void 543 fallback_symbol(sym_t *sym) 544 { 545 546 if (Tflag && fallback_symbol_strict_bool(sym)) 547 return; 548 549 if (funcsym != NULL && (strcmp(sym->s_name, "__FUNCTION__") == 0 || 550 strcmp(sym->s_name, "__PRETTY_FUNCTION__") == 0)) { 551 /* __FUNCTION__/__PRETTY_FUNCTION__ is a GCC extension */ 552 gnuism(316); 553 goto return_function_name; 554 } 555 556 if (funcsym != NULL && strcmp(sym->s_name, "__func__") == 0) { 557 if (!allow_c99) 558 /* __func__ is a C99 feature */ 559 warning(317); 560 /* C11 6.4.2.2 */ 561 return_function_name: 562 sym->s_type = block_derive_type(gettyp(CHAR), ARRAY); 563 sym->s_type->t_const = true; 564 sym->s_type->u.dimension = (int)strlen(funcsym->s_name) + 1; 565 return; 566 } 567 568 /* '%s' undefined */ 569 error(99, sym->s_name); 570 } 571 572 /* 573 * Functions that are predeclared by GCC or other compilers can be called 574 * with arbitrary arguments. Since lint usually runs after a successful 575 * compilation, it's the compiler's job to catch any errors. 576 */ 577 bool 578 is_compiler_builtin(const char *name) 579 { 580 /* https://gcc.gnu.org/onlinedocs/gcc/C-Extensions.html */ 581 if (allow_gcc) { 582 if (strncmp(name, "__atomic_", 9) == 0 || 583 strncmp(name, "__builtin_", 10) == 0 || 584 strcmp(name, "alloca") == 0 || 585 /* obsolete but still in use, as of 2021 */ 586 strncmp(name, "__sync_", 7) == 0) 587 return true; 588 } 589 590 /* https://software.intel.com/sites/landingpage/IntrinsicsGuide/ */ 591 if (strncmp(name, "_mm_", 4) == 0) 592 return true; 593 594 return false; 595 } 596 597 /* https://gcc.gnu.org/onlinedocs/gcc/Integer-Overflow-Builtins.html */ 598 static bool 599 is_gcc_bool_builtin(const char *name) 600 { 601 return strncmp(name, "__builtin_", 10) == 0 && 602 (str_ends_with(name, "_overflow") || 603 str_ends_with(name, "_overflow_p")); 604 } 605 606 static void 607 build_name_call(sym_t *sym) 608 { 609 610 if (is_compiler_builtin(sym->s_name)) { 611 /* 612 * Do not warn about these, just assume that they are regular 613 * functions compatible with non-prototype calling conventions. 614 */ 615 if (allow_gcc && is_gcc_bool_builtin(sym->s_name)) 616 sym->s_type = gettyp(BOOL); 617 } else if (allow_c99) 618 /* function '%s' implicitly declared to return int */ 619 error(215, sym->s_name); 620 else if (!allow_trad) 621 /* function '%s' implicitly declared to return int */ 622 warning(215, sym->s_name); 623 624 /* XXX if !allow_c90, the symbol should be exported to level 0 */ 625 sym->s_type = block_derive_type(sym->s_type, FUNC); 626 } 627 628 /* Create a node for a name (symbol table entry). */ 629 tnode_t * 630 build_name(sym_t *sym, bool is_funcname) 631 { 632 633 if (sym->s_scl == NO_SCL && !in_gcc_attribute) { 634 sym->s_scl = EXTERN; 635 sym->s_def = DECL; 636 if (is_funcname) 637 build_name_call(sym); 638 else 639 fallback_symbol(sym); 640 } 641 642 lint_assert(sym->s_kind == SK_VCFT || sym->s_kind == SK_MEMBER); 643 644 tnode_t *n = expr_alloc_tnode(); 645 n->tn_type = sym->s_type; 646 if (sym->s_scl == BOOL_CONST) { 647 n->tn_op = CON; 648 n->u.value.v_tspec = BOOL; 649 n->u.value.v_unsigned_since_c90 = false; 650 n->u.value.v_char_constant = false; 651 n->u.value.u.integer = sym->u.s_bool_constant ? 1 : 0; 652 } else if (sym->s_scl == ENUM_CONST) { 653 n->tn_op = CON; 654 n->u.value.v_tspec = INT; /* ENUM is in n->tn_type */ 655 n->u.value.v_unsigned_since_c90 = false; 656 n->u.value.v_char_constant = false; 657 n->u.value.u.integer = sym->u.s_enum_constant; 658 } else { 659 n->tn_op = NAME; 660 n->u.sym = sym; 661 if (sym->s_kind == SK_VCFT && sym->s_type->t_tspec != FUNC) 662 n->tn_lvalue = true; 663 } 664 665 return n; 666 } 667 668 tnode_t * 669 build_string(buffer *lit) 670 { 671 size_t value_len = lit->len; 672 if (lit->data != NULL) { 673 quoted_iterator it = { .end = 0 }; 674 for (value_len = 0; quoted_next(lit, &it); value_len++) 675 continue; 676 } 677 678 type_t *tp = expr_zero_alloc(sizeof(*tp), "type"); 679 tp->t_tspec = ARRAY; 680 tp->t_subt = gettyp(lit->data != NULL ? CHAR : WCHAR_TSPEC); 681 tp->u.dimension = (int)(value_len + 1); 682 683 tnode_t *n = expr_alloc_tnode(); 684 n->tn_op = STRING; 685 n->tn_type = tp; 686 n->tn_lvalue = true; 687 688 n->u.str_literals = expr_zero_alloc(sizeof(*n->u.str_literals), "tnode.string"); 689 n->u.str_literals->len = lit->len; 690 691 if (lit->data != NULL) { 692 n->u.str_literals->data = expr_zero_alloc(lit->len + 1, 693 "tnode.string.data"); 694 (void)memcpy(n->u.str_literals->data, lit->data, lit->len + 1); 695 free(lit->data); 696 } 697 free(lit); 698 699 return n; 700 } 701 702 tnode_t * 703 build_generic_selection(const tnode_t *expr, 704 struct generic_association *sel) 705 { 706 tnode_t *default_result = NULL; 707 708 for (; sel != NULL; sel = sel->ga_prev) { 709 if (expr != NULL && 710 types_compatible(sel->ga_arg, expr->tn_type, 711 false, false, NULL)) 712 return sel->ga_result; 713 else if (sel->ga_arg == NULL) 714 default_result = sel->ga_result; 715 } 716 return default_result; 717 } 718 719 static bool 720 is_out_of_char_range(const tnode_t *tn) 721 { 722 return tn->tn_op == CON && 723 !tn->u.value.v_char_constant && 724 !(0 <= tn->u.value.u.integer && 725 tn->u.value.u.integer < 1 << (CHAR_SIZE - 1)); 726 } 727 728 static bool 729 check_nonportable_char_comparison(op_t op, 730 const tnode_t *ln, tspec_t lt, 731 const tnode_t *rn, tspec_t rt) 732 { 733 if (!(hflag || pflag)) 734 return true; 735 736 if (lt == CHAR && is_out_of_char_range(rn)) { 737 char buf[128]; 738 (void)snprintf(buf, sizeof(buf), "%s %d", 739 op_name(op), (int)rn->u.value.u.integer); 740 /* nonportable character comparison '%s' */ 741 warning(230, buf); 742 return false; 743 } 744 if (rt == CHAR && is_out_of_char_range(ln)) { 745 char buf[128]; 746 (void)snprintf(buf, sizeof(buf), "%d %s ?", 747 (int)ln->u.value.u.integer, op_name(op)); 748 /* nonportable character comparison '%s' */ 749 warning(230, buf); 750 return false; 751 } 752 return true; 753 } 754 755 static void 756 check_integer_comparison(op_t op, tnode_t *ln, tnode_t *rn) 757 { 758 759 tspec_t lt = ln->tn_type->t_tspec; 760 tspec_t rt = rn->tn_type->t_tspec; 761 762 if (ln->tn_op != CON && rn->tn_op != CON) 763 return; 764 765 if (!is_integer(lt) || !is_integer(rt)) 766 return; 767 768 if (any_query_enabled && !in_system_header) { 769 if (lt == CHAR && rn->tn_op == CON && 770 !rn->u.value.v_char_constant) { 771 /* comparison '%s' of 'char' with plain integer %d */ 772 query_message(14, 773 op_name(op), (int)rn->u.value.u.integer); 774 } 775 if (rt == CHAR && ln->tn_op == CON && 776 !ln->u.value.v_char_constant) { 777 /* comparison '%s' of 'char' with plain integer %d */ 778 query_message(14, 779 op_name(op), (int)ln->u.value.u.integer); 780 } 781 } 782 783 if (!check_nonportable_char_comparison(op, ln, lt, rn, rt)) 784 return; 785 786 if (is_uinteger(lt) && !is_uinteger(rt) && 787 rn->tn_op == CON && rn->u.value.u.integer <= 0) { 788 if (rn->u.value.u.integer < 0) { 789 /* operator '%s' compares '%s' with '%s' */ 790 warning(162, op_name(op), 791 type_name(ln->tn_type), "negative constant"); 792 } else if (op == LT || op == GE) 793 /* operator '%s' compares '%s' with '%s' */ 794 warning(162, op_name(op), type_name(ln->tn_type), "0"); 795 return; 796 } 797 if (is_uinteger(rt) && !is_uinteger(lt) && 798 ln->tn_op == CON && ln->u.value.u.integer <= 0) { 799 if (ln->u.value.u.integer < 0) { 800 /* operator '%s' compares '%s' with '%s' */ 801 warning(162, op_name(op), 802 "negative constant", type_name(rn->tn_type)); 803 } else if (op == GT || op == LE) 804 /* operator '%s' compares '%s' with '%s' */ 805 warning(162, op_name(op), "0", type_name(rn->tn_type)); 806 return; 807 } 808 } 809 810 static const tspec_t arith_rank[] = { 811 LDOUBLE, DOUBLE, FLOAT, 812 #ifdef INT128_SIZE 813 UINT128, INT128, 814 #endif 815 ULLONG, LLONG, 816 ULONG, LONG, 817 UINT, INT, 818 }; 819 820 /* Keep unsigned in traditional C */ 821 static tspec_t 822 usual_arithmetic_conversion_trad(tspec_t lt, tspec_t rt) 823 { 824 825 size_t i; 826 for (i = 0; arith_rank[i] != INT; i++) 827 if (lt == arith_rank[i] || rt == arith_rank[i]) 828 break; 829 830 tspec_t t = arith_rank[i]; 831 if (is_uinteger(lt) || is_uinteger(rt)) 832 if (is_integer(t) && !is_uinteger(t)) 833 return unsigned_type(t); 834 return t; 835 } 836 837 static tspec_t 838 usual_arithmetic_conversion_c90(tspec_t lt, tspec_t rt) 839 { 840 841 if (lt == rt) 842 return lt; 843 844 if (lt == LCOMPLEX || rt == LCOMPLEX) 845 return LCOMPLEX; 846 if (lt == DCOMPLEX || rt == DCOMPLEX) 847 return DCOMPLEX; 848 if (lt == FCOMPLEX || rt == FCOMPLEX) 849 return FCOMPLEX; 850 if (lt == LDOUBLE || rt == LDOUBLE) 851 return LDOUBLE; 852 if (lt == DOUBLE || rt == DOUBLE) 853 return DOUBLE; 854 if (lt == FLOAT || rt == FLOAT) 855 return FLOAT; 856 857 if (size_in_bits(lt) > size_in_bits(rt)) 858 return lt; 859 if (size_in_bits(lt) < size_in_bits(rt)) 860 return rt; 861 862 size_t i; 863 for (i = 3; arith_rank[i] != INT; i++) 864 if (arith_rank[i] == lt || arith_rank[i] == rt) 865 break; 866 if ((is_uinteger(lt) || is_uinteger(rt)) && 867 !is_uinteger(arith_rank[i])) 868 i--; 869 return arith_rank[i]; 870 } 871 872 static tnode_t * 873 apply_usual_arithmetic_conversions(op_t op, tnode_t *tn, tspec_t t) 874 { 875 type_t *ntp = expr_dup_type(tn->tn_type); 876 ntp->t_tspec = t; 877 if (tn->tn_op != CON) { 878 /* usual arithmetic conversion for '%s' from '%s' to '%s' */ 879 query_message(4, op_name(op), 880 type_name(tn->tn_type), type_name(ntp)); 881 } 882 return convert(op, 0, ntp, tn); 883 } 884 885 /* 886 * Apply the "usual arithmetic conversions" (C99 6.3.1.8), which gives both 887 * operands the same type. 888 */ 889 static void 890 balance(op_t op, tnode_t **lnp, tnode_t **rnp) 891 { 892 893 tspec_t lt = (*lnp)->tn_type->t_tspec; 894 tspec_t rt = (*rnp)->tn_type->t_tspec; 895 if (!is_arithmetic(lt) || !is_arithmetic(rt)) 896 return; 897 898 tspec_t t = allow_c90 899 ? usual_arithmetic_conversion_c90(lt, rt) 900 : usual_arithmetic_conversion_trad(lt, rt); 901 902 if (modtab[op].m_comparison 903 && is_integer(lt) && (*lnp)->tn_op != CON 904 && is_floating(t) && (*rnp)->tn_op == CON) 905 /* comparing integer '%s' to floating point constant %Lg */ 906 warning(379, type_name((*lnp)->tn_type), 907 (*rnp)->u.value.u.floating); 908 909 if (t != lt) 910 *lnp = apply_usual_arithmetic_conversions(op, *lnp, t); 911 if (t != rt) 912 *rnp = apply_usual_arithmetic_conversions(op, *rnp, t); 913 914 if (is_integer(t)) { 915 unsigned lw = width_in_bits((*lnp)->tn_type); 916 unsigned rw = width_in_bits((*rnp)->tn_type); 917 if (lw < rw) 918 *lnp = convert(NOOP, 0, (*rnp)->tn_type, *lnp); 919 if (rw < lw) 920 *rnp = convert(NOOP, 0, (*lnp)->tn_type, *rnp); 921 } 922 } 923 924 static tnode_t * 925 build_address(bool sys, tnode_t *tn, bool force) 926 { 927 tspec_t t; 928 929 if (!force && ((t = tn->tn_type->t_tspec) == ARRAY || t == FUNC)) { 930 if (!allow_c90) 931 /* '&' before array or function: ignored */ 932 warning(127); 933 return tn; 934 } 935 936 /* eliminate '&*' */ 937 if (tn->tn_op == INDIR && 938 tn->u.ops.left->tn_type->t_tspec == PTR && 939 tn->u.ops.left->tn_type->t_subt == tn->tn_type) { 940 return tn->u.ops.left; 941 } 942 943 return build_op(ADDR, sys, expr_derive_type(tn->tn_type, PTR), 944 tn, NULL); 945 } 946 947 static uint64_t 948 fold_unsigned_integer(op_t op, uint64_t l, uint64_t r, 949 uint64_t max_value, bool *overflow) 950 { 951 switch (op) { 952 case COMPL: 953 return ~l & max_value; 954 case UPLUS: 955 return +l; 956 case UMINUS: 957 return -l & max_value; 958 case MULT: 959 *overflow = r > 0 && l > max_value / r; 960 return l * r; 961 case DIV: 962 if (r == 0) { 963 /* division by 0 */ 964 error(139); 965 return max_value; 966 } 967 return l / r; 968 case MOD: 969 if (r == 0) { 970 /* modulus by 0 */ 971 error(140); 972 return 0; 973 } 974 return l % r; 975 case PLUS: 976 *overflow = l > max_value - r; 977 return l + r; 978 case MINUS: 979 *overflow = l < r; 980 return l - r; 981 case SHL: 982 /* TODO: warn about out-of-bounds 'r'. */ 983 /* TODO: warn about overflow. */ 984 return l << (r & 63); 985 case SHR: 986 /* TODO: warn about out-of-bounds 'r'. */ 987 return l >> (r & 63); 988 case LT: 989 return l < r ? 1 : 0; 990 case LE: 991 return l <= r ? 1 : 0; 992 case GT: 993 return l > r ? 1 : 0; 994 case GE: 995 return l >= r ? 1 : 0; 996 case EQ: 997 return l == r ? 1 : 0; 998 case NE: 999 return l != r ? 1 : 0; 1000 case BITAND: 1001 return l & r; 1002 case BITXOR: 1003 return l ^ r; 1004 case BITOR: 1005 return l | r; 1006 default: 1007 lint_assert(/*CONSTCOND*/false); 1008 /* NOTREACHED */ 1009 } 1010 } 1011 1012 static int64_t 1013 fold_signed_integer(op_t op, int64_t l, int64_t r, 1014 int64_t min_value, int64_t max_value, bool *overflow) 1015 { 1016 switch (op) { 1017 case COMPL: 1018 return ~l; 1019 case UPLUS: 1020 return +l; 1021 case UMINUS: 1022 *overflow = l == min_value; 1023 return *overflow ? l : -l; 1024 case MULT:; 1025 uint64_t al = l >= 0 ? (uint64_t)l : -(uint64_t)l; 1026 uint64_t ar = r >= 0 ? (uint64_t)r : -(uint64_t)r; 1027 bool neg = (l >= 0) != (r >= 0); 1028 uint64_t max_prod = (uint64_t)max_value + (neg ? 1 : 0); 1029 if (al > 0 && ar > max_prod / al) { 1030 *overflow = true; 1031 return neg ? min_value : max_value; 1032 } 1033 return l * r; 1034 case DIV: 1035 if (r == 0) { 1036 /* division by 0 */ 1037 error(139); 1038 return max_value; 1039 } 1040 if (l == min_value && r == -1) { 1041 *overflow = true; 1042 return l; 1043 } 1044 return l / r; 1045 case MOD: 1046 if (r == 0) { 1047 /* modulus by 0 */ 1048 error(140); 1049 return 0; 1050 } 1051 if (l == min_value && r == -1) { 1052 *overflow = true; 1053 return 0; 1054 } 1055 return l % r; 1056 case PLUS: 1057 if (r > 0 && l > max_value - r) { 1058 *overflow = true; 1059 return max_value; 1060 } 1061 if (r < 0 && l < min_value - r) { 1062 *overflow = true; 1063 return min_value; 1064 } 1065 return l + r; 1066 case MINUS: 1067 if (r > 0 && l < min_value + r) { 1068 *overflow = true; 1069 return min_value; 1070 } 1071 if (r < 0 && l > max_value + r) { 1072 *overflow = true; 1073 return max_value; 1074 } 1075 return l - r; 1076 case SHL: 1077 /* TODO: warn about out-of-bounds 'r'. */ 1078 /* TODO: warn about overflow. */ 1079 return l << (r & 63); 1080 case SHR: 1081 /* TODO: warn about out-of-bounds 'r'. */ 1082 if (l < 0) 1083 return (int64_t)~(~(uint64_t)l >> (r & 63)); 1084 return (int64_t)((uint64_t)l >> (r & 63)); 1085 case LT: 1086 return l < r ? 1 : 0; 1087 case LE: 1088 return l <= r ? 1 : 0; 1089 case GT: 1090 return l > r ? 1 : 0; 1091 case GE: 1092 return l >= r ? 1 : 0; 1093 case EQ: 1094 return l == r ? 1 : 0; 1095 case NE: 1096 return l != r ? 1 : 0; 1097 case BITAND: 1098 return l & r; 1099 case BITXOR: 1100 return l ^ r; 1101 case BITOR: 1102 return l | r; 1103 default: 1104 lint_assert(/*CONSTCOND*/false); 1105 /* NOTREACHED */ 1106 } 1107 } 1108 1109 static tnode_t * 1110 fold_constant_integer(tnode_t *tn) 1111 { 1112 1113 lint_assert(has_operands(tn)); 1114 tspec_t t = tn->u.ops.left->tn_type->t_tspec; 1115 int64_t l = tn->u.ops.left->u.value.u.integer; 1116 int64_t r = is_binary(tn) ? tn->u.ops.right->u.value.u.integer : 0; 1117 uint64_t mask = value_bits(size_in_bits(t)); 1118 1119 int64_t res; 1120 bool overflow = false; 1121 if (!is_integer(t) || is_uinteger(t)) { 1122 uint64_t u_res = fold_unsigned_integer(tn->tn_op, 1123 (uint64_t)l, (uint64_t)r, mask, &overflow); 1124 if (u_res > mask) 1125 overflow = true; 1126 res = (int64_t)u_res; 1127 if (overflow && hflag) { 1128 char buf[128]; 1129 if (is_binary(tn)) { 1130 snprintf(buf, sizeof(buf), "%ju %s %ju", 1131 (uintmax_t)l, op_name(tn->tn_op), 1132 (uintmax_t)r); 1133 } else { 1134 snprintf(buf, sizeof(buf), "%s%ju", 1135 op_name(tn->tn_op), (uintmax_t)l); 1136 } 1137 /* '%s' overflows '%s' */ 1138 warning(141, buf, type_name(tn->tn_type)); 1139 } 1140 } else { 1141 int64_t max_value = (int64_t)(mask >> 1); 1142 int64_t min_value = -max_value - 1; 1143 res = fold_signed_integer(tn->tn_op, 1144 l, r, min_value, max_value, &overflow); 1145 if (res < min_value || res > max_value) 1146 overflow = true; 1147 if (overflow && hflag) { 1148 char buf[128]; 1149 if (is_binary(tn)) { 1150 snprintf(buf, sizeof(buf), "%jd %s %jd", 1151 (intmax_t)l, op_name(tn->tn_op), 1152 (intmax_t)r); 1153 } else if (tn->tn_op == UMINUS && l < 0) { 1154 snprintf(buf, sizeof(buf), "-(%jd)", 1155 (intmax_t)l); 1156 } else { 1157 snprintf(buf, sizeof(buf), "%s%jd", 1158 op_name(tn->tn_op), (intmax_t)l); 1159 } 1160 /* '%s' overflows '%s' */ 1161 warning(141, buf, type_name(tn->tn_type)); 1162 } 1163 } 1164 1165 val_t *v = xcalloc(1, sizeof(*v)); 1166 v->v_tspec = tn->tn_type->t_tspec; 1167 v->u.integer = convert_integer(res, t, size_in_bits(t)); 1168 1169 tnode_t *cn = build_constant(tn->tn_type, v); 1170 if (tn->u.ops.left->tn_system_dependent) 1171 cn->tn_system_dependent = true; 1172 if (is_binary(tn) && tn->u.ops.right->tn_system_dependent) 1173 cn->tn_system_dependent = true; 1174 1175 return cn; 1176 } 1177 1178 static tnode_t * 1179 build_struct_access(op_t op, bool sys, tnode_t *ln, tnode_t *rn) 1180 { 1181 1182 lint_assert(rn->tn_op == NAME); 1183 lint_assert(is_member(rn->u.sym)); 1184 1185 bool lvalue = op == ARROW || ln->tn_lvalue; 1186 1187 if (op == POINT) 1188 ln = build_address(sys, ln, true); 1189 else if (ln->tn_type->t_tspec != PTR) { 1190 lint_assert(!allow_c90); 1191 lint_assert(is_integer(ln->tn_type->t_tspec)); 1192 ln = convert(NOOP, 0, expr_derive_type(gettyp(VOID), PTR), ln); 1193 } 1194 1195 tnode_t *ctn = build_integer_constant(PTRDIFF_TSPEC, 1196 rn->u.sym->u.s_member.sm_offset_in_bits / CHAR_SIZE); 1197 1198 type_t *ptr_tp = expr_derive_type(rn->tn_type, PTR); 1199 tnode_t *ntn = build_op(PLUS, sys, ptr_tp, ln, ctn); 1200 if (ln->tn_op == CON) 1201 ntn = fold_constant_integer(ntn); 1202 1203 op_t nop = rn->tn_type->t_bitfield ? FSEL : INDIR; 1204 ntn = build_op(nop, sys, ntn->tn_type->t_subt, ntn, NULL); 1205 if (!lvalue) 1206 ntn->tn_lvalue = false; 1207 1208 return ntn; 1209 } 1210 1211 /* 1212 * Get the size in bytes of type tp->t_subt, as a constant expression of type 1213 * ptrdiff_t as seen from the target platform. 1214 */ 1215 static tnode_t * 1216 subt_size_in_bytes(type_t *tp) 1217 { 1218 1219 lint_assert(tp->t_tspec == PTR); 1220 tp = tp->t_subt; 1221 1222 int elem = 1; 1223 while (tp->t_tspec == ARRAY) { 1224 elem *= tp->u.dimension; 1225 tp = tp->t_subt; 1226 } 1227 1228 int elsz_in_bits = 0; 1229 switch (tp->t_tspec) { 1230 case FUNC: 1231 /* pointer to function is not allowed here */ 1232 error(110); 1233 break; 1234 case VOID: 1235 /* cannot do pointer arithmetic on operand of unknown size */ 1236 gnuism(136); 1237 break; 1238 case STRUCT: 1239 case UNION: 1240 if ((elsz_in_bits = (int)tp->u.sou->sou_size_in_bits) == 0) 1241 /* cannot do pointer arithmetic on operand of ... */ 1242 error(136); 1243 break; 1244 case ENUM: 1245 if (is_incomplete(tp)) 1246 /* cannot do pointer arithmetic on operand of ... */ 1247 warning(136); 1248 /* FALLTHROUGH */ 1249 default: 1250 if ((elsz_in_bits = size_in_bits(tp->t_tspec)) == 0) 1251 /* cannot do pointer arithmetic on operand of ... */ 1252 error(136); 1253 else 1254 lint_assert(elsz_in_bits != -1); 1255 break; 1256 } 1257 1258 if (elem == 0 && elsz_in_bits != 0) 1259 /* cannot do pointer arithmetic on operand of unknown size */ 1260 error(136); 1261 1262 if (elsz_in_bits == 0) 1263 elsz_in_bits = CHAR_SIZE; 1264 1265 return build_integer_constant(PTRDIFF_TSPEC, 1266 (int64_t)(elem * elsz_in_bits / CHAR_SIZE)); 1267 } 1268 1269 static tnode_t * 1270 build_prepost_incdec(op_t op, bool sys, tnode_t *ln) 1271 { 1272 1273 lint_assert(ln != NULL); 1274 tnode_t *cn = ln->tn_type->t_tspec == PTR 1275 ? subt_size_in_bytes(ln->tn_type) 1276 : build_integer_constant(INT, 1); 1277 return build_op(op, sys, ln->tn_type, ln, cn); 1278 } 1279 1280 static void 1281 check_enum_array_index(const tnode_t *ln, const tnode_t *rn) 1282 { 1283 1284 if (ln->tn_op != ADDR || ln->u.ops.left->tn_op != NAME) 1285 return; 1286 1287 const type_t *ltp = ln->u.ops.left->tn_type; 1288 if (ltp->t_tspec != ARRAY || ltp->t_incomplete_array) 1289 return; 1290 1291 if (rn->tn_op != CVT || !rn->tn_type->t_is_enum) 1292 return; 1293 if (rn->u.ops.left->tn_op != LOAD) 1294 return; 1295 1296 const type_t *rtp = rn->u.ops.left->tn_type; 1297 const sym_t *ec = rtp->u.enumer->en_first_enumerator; 1298 const sym_t *max_ec = ec; 1299 lint_assert(ec != NULL); 1300 for (ec = ec->s_next; ec != NULL; ec = ec->s_next) 1301 if (ec->u.s_enum_constant > max_ec->u.s_enum_constant) 1302 max_ec = ec; 1303 1304 int64_t max_enum_value = max_ec->u.s_enum_constant; 1305 lint_assert(INT_MIN <= max_enum_value && max_enum_value <= INT_MAX); 1306 1307 int max_array_index = ltp->u.dimension - 1; 1308 if (max_enum_value == max_array_index) 1309 return; 1310 1311 if (max_enum_value == max_array_index + 1 && 1312 (strstr(max_ec->s_name, "MAX") != NULL || 1313 strstr(max_ec->s_name, "max") != NULL || 1314 strstr(max_ec->s_name, "NUM") != NULL || 1315 strstr(max_ec->s_name, "num") != NULL || 1316 strncmp(max_ec->s_name, "N_", 2) == 0)) 1317 return; 1318 1319 /* maximum value %d for '%s' of type '%s' does not match maximum array index %d */ 1320 warning(348, (int)max_enum_value, max_ec->s_name, type_name(rtp), 1321 max_array_index); 1322 print_previous_declaration(max_ec); 1323 } 1324 1325 static tnode_t * 1326 build_plus_minus(op_t op, bool sys, tnode_t *ln, tnode_t *rn) 1327 { 1328 1329 if (rn->tn_type->t_tspec == PTR && is_integer(ln->tn_type->t_tspec)) { 1330 tnode_t *tmp = ln; 1331 ln = rn; 1332 rn = tmp; 1333 /* pointer addition has integer on the left-hand side */ 1334 query_message(5); 1335 } 1336 1337 /* pointer +- integer */ 1338 tspec_t lt = ln->tn_type->t_tspec; 1339 tspec_t rt = rn->tn_type->t_tspec; 1340 if (lt == PTR && rt != PTR) { 1341 lint_assert(is_integer(rt)); 1342 1343 check_ctype_macro_invocation(ln, rn); 1344 check_enum_array_index(ln, rn); 1345 1346 tnode_t *elsz = subt_size_in_bytes(ln->tn_type); 1347 tspec_t szt = elsz->tn_type->t_tspec; 1348 if (rt != szt && rt != unsigned_type(szt)) 1349 rn = convert(NOOP, 0, elsz->tn_type, rn); 1350 1351 tnode_t *prod = build_op(MULT, sys, rn->tn_type, rn, elsz); 1352 if (rn->tn_op == CON) 1353 prod = fold_constant_integer(prod); 1354 1355 return build_op(op, sys, ln->tn_type, ln, prod); 1356 } 1357 1358 /* pointer - pointer */ 1359 if (rt == PTR) { 1360 lint_assert(lt == PTR); 1361 lint_assert(op == MINUS); 1362 1363 type_t *ptrdiff = gettyp(PTRDIFF_TSPEC); 1364 tnode_t *raw_diff = build_op(op, sys, ptrdiff, ln, rn); 1365 if (ln->tn_op == CON && rn->tn_op == CON) 1366 raw_diff = fold_constant_integer(raw_diff); 1367 1368 tnode_t *elsz = subt_size_in_bytes(ln->tn_type); 1369 balance(NOOP, &raw_diff, &elsz); 1370 1371 return build_op(DIV, sys, ptrdiff, raw_diff, elsz); 1372 } 1373 1374 return build_op(op, sys, ln->tn_type, ln, rn); 1375 } 1376 1377 static tnode_t * 1378 build_bit_shift(op_t op, bool sys, tnode_t *ln, tnode_t *rn) 1379 { 1380 1381 if (!allow_c90 && rn->tn_type->t_tspec != INT) 1382 // XXX: C1978 7.5 says: "Both [operators] perform the usual 1383 // arithmetic conversions on their operands." 1384 // TODO: Add a test to exercise this part of the code. 1385 rn = convert(NOOP, 0, gettyp(INT), rn); 1386 return build_op(op, sys, ln->tn_type, ln, rn); 1387 } 1388 1389 static bool 1390 is_null_pointer(const tnode_t *tn) 1391 { 1392 tspec_t t = tn->tn_type->t_tspec; 1393 1394 // TODO: Investigate how other pointers are stored, in particular, 1395 // whether a pointer constant can have a non-zero value. 1396 // If not, simplify the code below. 1397 return ((t == PTR && tn->tn_type->t_subt->t_tspec == VOID) 1398 || is_integer(t)) 1399 && (tn->tn_op == CON && tn->u.value.u.integer == 0); 1400 } 1401 1402 /* Return a type based on tp1, with added qualifiers from tp2. */ 1403 static type_t * 1404 merge_qualifiers(type_t *tp1, const type_t *tp2) 1405 { 1406 1407 lint_assert(tp1->t_tspec == PTR); 1408 lint_assert(tp2->t_tspec == PTR); 1409 1410 bool c1 = tp1->t_subt->t_const; 1411 bool c2 = tp2->t_subt->t_const; 1412 bool v1 = tp1->t_subt->t_volatile; 1413 bool v2 = tp2->t_subt->t_volatile; 1414 1415 if (c1 == (c1 | c2) && v1 == (v1 | v2)) 1416 return tp1; 1417 1418 type_t *nstp = expr_dup_type(tp1->t_subt); 1419 nstp->t_const |= c2; 1420 nstp->t_volatile |= v2; 1421 1422 type_t *ntp = expr_dup_type(tp1); 1423 ntp->t_subt = nstp; 1424 return ntp; 1425 } 1426 1427 /* See C99 6.5.15 "Conditional operator". */ 1428 static tnode_t * 1429 build_colon(bool sys, tnode_t *ln, tnode_t *rn) 1430 { 1431 tspec_t lt = ln->tn_type->t_tspec; 1432 tspec_t rt = rn->tn_type->t_tspec; 1433 1434 type_t *tp; 1435 if (is_arithmetic(lt) && is_arithmetic(rt)) 1436 /* The operands were already balanced in build_binary. */ 1437 tp = ln->tn_type; 1438 else if (lt == BOOL && rt == BOOL) 1439 tp = ln->tn_type; 1440 else if (lt == VOID || rt == VOID) 1441 tp = gettyp(VOID); 1442 else if (is_struct_or_union(lt)) { 1443 lint_assert(is_struct_or_union(rt)); 1444 lint_assert(ln->tn_type->u.sou == rn->tn_type->u.sou); 1445 if (is_incomplete(ln->tn_type)) { 1446 /* unknown operand size, op '%s' */ 1447 error(138, op_name(COLON)); 1448 return NULL; 1449 } 1450 tp = ln->tn_type; 1451 } else if (lt == PTR && is_integer(rt)) { 1452 if (rt != PTRDIFF_TSPEC) 1453 rn = convert(NOOP, 0, gettyp(PTRDIFF_TSPEC), rn); 1454 tp = ln->tn_type; 1455 } else if (rt == PTR && is_integer(lt)) { 1456 if (lt != PTRDIFF_TSPEC) 1457 ln = convert(NOOP, 0, gettyp(PTRDIFF_TSPEC), ln); 1458 tp = rn->tn_type; 1459 } else if (lt == PTR && is_null_pointer(rn)) 1460 tp = merge_qualifiers(ln->tn_type, rn->tn_type); 1461 else if (rt == PTR && is_null_pointer(ln)) 1462 tp = merge_qualifiers(rn->tn_type, ln->tn_type); 1463 else if (lt == PTR && ln->tn_type->t_subt->t_tspec == VOID) 1464 tp = merge_qualifiers(ln->tn_type, rn->tn_type); 1465 else if (rt == PTR && rn->tn_type->t_subt->t_tspec == VOID) 1466 tp = merge_qualifiers(rn->tn_type, ln->tn_type); 1467 else { 1468 /* 1469 * XXX For now we simply take the left type. This is probably 1470 * wrong, if one type contains a function prototype and the 1471 * other one, at the same place, only an old-style declaration. 1472 */ 1473 tp = merge_qualifiers(ln->tn_type, rn->tn_type); 1474 } 1475 1476 return build_op(COLON, sys, tp, ln, rn); 1477 } 1478 1479 /* TODO: check for varargs */ 1480 static bool 1481 is_cast_redundant(const tnode_t *tn) 1482 { 1483 const type_t *ntp = tn->tn_type, *otp = tn->u.ops.left->tn_type; 1484 tspec_t nt = ntp->t_tspec, ot = otp->t_tspec; 1485 1486 if (nt == BOOL || ot == BOOL) 1487 return nt == BOOL && ot == BOOL; 1488 1489 if (is_integer(nt) && is_integer(ot)) { 1490 unsigned int nw = width_in_bits(ntp), ow = width_in_bits(otp); 1491 if (is_uinteger(nt) == is_uinteger(ot)) 1492 return nw >= ow; 1493 return is_uinteger(ot) && nw > ow; 1494 } 1495 1496 if (is_complex(nt) || is_complex(ot)) 1497 return is_complex(nt) && is_complex(ot) && 1498 size_in_bits(nt) >= size_in_bits(ot); 1499 1500 if (is_floating(nt) && is_floating(ot)) 1501 return size_in_bits(nt) >= size_in_bits(ot); 1502 1503 if (nt == PTR && ot == PTR) { 1504 if (!ntp->t_subt->t_const && otp->t_subt->t_const) 1505 return false; 1506 if (!ntp->t_subt->t_volatile && otp->t_subt->t_volatile) 1507 return false; 1508 1509 if (ntp->t_subt->t_tspec == VOID || 1510 otp->t_subt->t_tspec == VOID || 1511 types_compatible(ntp->t_subt, otp->t_subt, 1512 false, false, NULL)) 1513 return true; 1514 } 1515 1516 return false; 1517 } 1518 1519 static bool 1520 is_assignment(op_t op) 1521 { 1522 1523 return op == ASSIGN || 1524 op == MULASS || 1525 op == DIVASS || 1526 op == MODASS || 1527 op == ADDASS || 1528 op == SUBASS || 1529 op == SHLASS || 1530 op == SHRASS || 1531 op == ANDASS || 1532 op == XORASS || 1533 op == ORASS || 1534 op == RETURN || 1535 op == INIT; 1536 } 1537 1538 static tnode_t * 1539 build_assignment(op_t op, bool sys, tnode_t *ln, tnode_t *rn) 1540 { 1541 1542 tspec_t lt = ln->tn_type->t_tspec; 1543 tspec_t rt = rn->tn_type->t_tspec; 1544 1545 if (is_assignment(rn->tn_op)) 1546 /* chained assignment with '%s' and '%s' */ 1547 query_message(10, op_name(op), op_name(rn->tn_op)); 1548 1549 if ((op == ADDASS || op == SUBASS) && lt == PTR) { 1550 lint_assert(is_integer(rt)); 1551 tnode_t *ctn = subt_size_in_bytes(ln->tn_type); 1552 if (rn->tn_type->t_tspec != ctn->tn_type->t_tspec) 1553 rn = convert(NOOP, 0, ctn->tn_type, rn); 1554 rn = build_op(MULT, sys, rn->tn_type, rn, ctn); 1555 if (rn->u.ops.left->tn_op == CON) 1556 rn = fold_constant_integer(rn); 1557 } 1558 1559 if ((op == ASSIGN || op == RETURN || op == INIT) && 1560 (lt == STRUCT || rt == STRUCT)) { 1561 lint_assert(lt == rt); 1562 lint_assert(ln->tn_type->u.sou == rn->tn_type->u.sou); 1563 if (is_incomplete(ln->tn_type)) { 1564 if (op == RETURN) 1565 /* cannot return incomplete type */ 1566 error(212); 1567 else 1568 /* unknown operand size, op '%s' */ 1569 error(138, op_name(op)); 1570 return NULL; 1571 } 1572 } 1573 1574 if (op == SHLASS && hflag && allow_trad && allow_c90 1575 && portable_rank_cmp(lt, rt) < 0) 1576 /* semantics of '%s' change in C90; ... */ 1577 warning(118, "<<="); 1578 1579 if (op != SHLASS && op != SHRASS 1580 && (op == ASSIGN || lt != PTR) 1581 && (lt != rt || (ln->tn_type->t_bitfield && rn->tn_op == CON))) { 1582 rn = convert(op, 0, ln->tn_type, rn); 1583 rt = lt; 1584 } 1585 1586 if (lt == PTR && ln->tn_type->t_subt->t_tspec != VOID 1587 && rt == PTR && rn->tn_type->t_subt->t_tspec == VOID 1588 && !is_null_pointer(rn)) 1589 /* implicit narrowing conversion from void ... */ 1590 query_message(20, type_name(ln->tn_type)); 1591 1592 if (any_query_enabled && rn->tn_op == CVT && rn->tn_cast && 1593 types_compatible(ln->tn_type, rn->tn_type, false, false, NULL) && 1594 is_cast_redundant(rn)) { 1595 /* redundant cast from '%s' to '%s' before assignment */ 1596 query_message(7, type_name(rn->u.ops.left->tn_type), 1597 type_name(rn->tn_type)); 1598 } 1599 1600 return build_op(op, sys, ln->tn_type, ln, rn); 1601 } 1602 1603 static tnode_t * 1604 build_real_imag(op_t op, bool sys, tnode_t *ln) 1605 { 1606 1607 lint_assert(ln != NULL); 1608 if (ln->tn_op == NAME) { 1609 /* 1610 * This may be too much, but it avoids wrong warnings. See 1611 * d_c99_complex_split.c. 1612 */ 1613 mark_as_used(ln->u.sym, false, false); 1614 mark_as_set(ln->u.sym); 1615 } 1616 1617 tspec_t t; 1618 switch (ln->tn_type->t_tspec) { 1619 case LCOMPLEX: 1620 t = LDOUBLE; 1621 break; 1622 case DCOMPLEX: 1623 t = DOUBLE; 1624 break; 1625 case FCOMPLEX: 1626 t = FLOAT; 1627 break; 1628 default: 1629 /* '__%s__' is illegal for type '%s' */ 1630 error(276, op == REAL ? "real" : "imag", 1631 type_name(ln->tn_type)); 1632 return NULL; 1633 } 1634 1635 tnode_t *ntn = build_op(op, sys, gettyp(t), ln, NULL); 1636 ntn->tn_lvalue = true; 1637 return ntn; 1638 } 1639 1640 static bool 1641 is_confusing_precedence(op_t op, const tnode_t *operand, op_t *cop) 1642 { 1643 if (operand->tn_parenthesized) 1644 return false; 1645 op_t oop = operand->tn_op; 1646 1647 if (op == SHL || op == SHR) { 1648 if (oop == PLUS || oop == MINUS) 1649 return *cop = oop, true; 1650 return false; 1651 } 1652 1653 if (op == LOGOR) { 1654 if (oop == LOGAND) 1655 return *cop = oop, true; 1656 return false; 1657 } 1658 1659 lint_assert(op == BITAND || op == BITXOR || op == BITOR); 1660 if (oop != op 1661 && (oop == PLUS || oop == MINUS || oop == BITAND || oop == BITXOR)) 1662 return *cop = oop, true; 1663 return false; 1664 } 1665 1666 /* 1667 * Print a warning if the given node has operands which should be 1668 * parenthesized. 1669 * 1670 * XXX Does not work if an operand is a constant expression. Constant 1671 * expressions are already folded. 1672 */ 1673 static void 1674 check_precedence_confusion(tnode_t *tn) 1675 { 1676 tnode_t *ln, *rn; 1677 1678 if (!hflag) 1679 return; 1680 1681 debug_node(tn); 1682 1683 lint_assert(is_binary(tn)); 1684 for (ln = tn->u.ops.left; ln->tn_op == CVT; ln = ln->u.ops.left) 1685 continue; 1686 for (rn = tn->u.ops.right; rn->tn_op == CVT; rn = rn->u.ops.left) 1687 continue; 1688 1689 op_t cop; 1690 if (is_confusing_precedence(tn->tn_op, ln, &cop) || 1691 is_confusing_precedence(tn->tn_op, rn, &cop)) { 1692 /* possible precedence confusion between '%s' and '%s' */ 1693 warning(169, op_name(tn->tn_op), op_name(cop)); 1694 } 1695 } 1696 1697 static tnode_t * 1698 fold_constant_compare_zero(tnode_t *tn) 1699 { 1700 1701 val_t *v = xcalloc(1, sizeof(*v)); 1702 v->v_tspec = tn->tn_type->t_tspec; 1703 lint_assert(v->v_tspec == INT || (Tflag && v->v_tspec == BOOL)); 1704 1705 lint_assert(has_operands(tn)); 1706 bool l = constant_is_nonzero(tn->u.ops.left); 1707 bool r = is_binary(tn) && constant_is_nonzero(tn->u.ops.right); 1708 1709 switch (tn->tn_op) { 1710 case NOT: 1711 if (hflag && !suppress_constcond) 1712 /* constant operand to '!' */ 1713 warning(239); 1714 v->u.integer = !l ? 1 : 0; 1715 break; 1716 case LOGAND: 1717 v->u.integer = l && r ? 1 : 0; 1718 break; 1719 case LOGOR: 1720 v->u.integer = l || r ? 1 : 0; 1721 break; 1722 default: 1723 lint_assert(/*CONSTCOND*/false); 1724 } 1725 1726 return build_constant(tn->tn_type, v); 1727 } 1728 1729 static long double 1730 floating_error_value(tspec_t t, long double lv) 1731 { 1732 if (t == FLOAT) 1733 return lv < 0 ? -FLT_MAX : FLT_MAX; 1734 if (t == DOUBLE) 1735 return lv < 0 ? -DBL_MAX : DBL_MAX; 1736 /* 1737 * When NetBSD is cross-built in MKLINT=yes mode on x86_64 for sparc64, 1738 * tools/lint checks this code while building usr.bin/xlint. In that 1739 * situation, lint uses the preprocessor for sparc64, in which the type 1740 * 'long double' is IEEE-754-binary128, affecting the macro LDBL_MAX 1741 * below. The type 'long double', as well as the strtold 1742 * implementation, comes from the host platform x86_64 though, where 1743 * 'long double' consumes 128 bits as well but only uses 80 of them. 1744 * The exponent range of the two 'long double' types is the same, but 1745 * the maximum finite value differs due to the extended precision on 1746 * sparc64. 1747 * 1748 * To properly handle the data types of the target platform, lint would 1749 * have to implement the floating-point types in a platform-independent 1750 * way, which is not worth the effort, given how few programs 1751 * practically use 'long double'. 1752 */ 1753 /* LINTED 248: floating-point constant out of range */ 1754 long double max = LDBL_MAX; 1755 return lv < 0 ? -max : max; 1756 } 1757 1758 static bool 1759 is_floating_overflow(tspec_t t, long double val) 1760 { 1761 if (fpe != 0 || isfinite(val) == 0) 1762 return true; 1763 if (t == FLOAT && (val > FLT_MAX || val < -FLT_MAX)) 1764 return true; 1765 if (t == DOUBLE && (val > DBL_MAX || val < -DBL_MAX)) 1766 return true; 1767 return false; 1768 } 1769 1770 static tnode_t * 1771 fold_constant_floating(tnode_t *tn) 1772 { 1773 1774 fpe = 0; 1775 1776 tspec_t t = tn->tn_type->t_tspec; 1777 1778 val_t *v = xcalloc(1, sizeof(*v)); 1779 v->v_tspec = t; 1780 1781 lint_assert(is_floating(t)); 1782 lint_assert(has_operands(tn)); 1783 lint_assert(t == tn->u.ops.left->tn_type->t_tspec); 1784 lint_assert(!is_binary(tn) || t == tn->u.ops.right->tn_type->t_tspec); 1785 1786 long double lv = tn->u.ops.left->u.value.u.floating; 1787 long double rv = is_binary(tn) ? tn->u.ops.right->u.value.u.floating 1788 : 0.0; 1789 1790 switch (tn->tn_op) { 1791 case UPLUS: 1792 v->u.floating = lv; 1793 break; 1794 case UMINUS: 1795 v->u.floating = -lv; 1796 break; 1797 case MULT: 1798 v->u.floating = lv * rv; 1799 break; 1800 case DIV: 1801 if (rv == 0.0) { 1802 /* division by 0 */ 1803 error(139); 1804 v->u.floating = floating_error_value(t, lv); 1805 } else { 1806 v->u.floating = lv / rv; 1807 } 1808 break; 1809 case PLUS: 1810 v->u.floating = lv + rv; 1811 break; 1812 case MINUS: 1813 v->u.floating = lv - rv; 1814 break; 1815 case LT: 1816 v->u.integer = lv < rv ? 1 : 0; 1817 break; 1818 case LE: 1819 v->u.integer = lv <= rv ? 1 : 0; 1820 break; 1821 case GE: 1822 v->u.integer = lv >= rv ? 1 : 0; 1823 break; 1824 case GT: 1825 v->u.integer = lv > rv ? 1 : 0; 1826 break; 1827 case EQ: 1828 v->u.integer = lv == rv ? 1 : 0; 1829 break; 1830 case NE: 1831 v->u.integer = lv != rv ? 1 : 0; 1832 break; 1833 default: 1834 lint_assert(/*CONSTCOND*/false); 1835 } 1836 1837 // XXX: Must not access u.floating after setting u.integer. 1838 lint_assert(fpe != 0 || isnan(v->u.floating) == 0); 1839 if (is_complex(v->v_tspec)) { 1840 /* 1841 * Don't warn, as lint doesn't model the imaginary part of 1842 * complex numbers. 1843 */ 1844 fpe = 0; 1845 } else if (is_floating_overflow(t, v->u.floating)) { 1846 /* operator '%s' produces floating point overflow */ 1847 warning(142, op_name(tn->tn_op)); 1848 v->u.floating = floating_error_value(t, v->u.floating); 1849 fpe = 0; 1850 } 1851 1852 return build_constant(tn->tn_type, v); 1853 } 1854 1855 static void 1856 use(const tnode_t *tn) 1857 { 1858 if (tn == NULL) 1859 return; 1860 switch (tn->tn_op) { 1861 case NAME: 1862 mark_as_used(tn->u.sym, false /* XXX */, false /* XXX */); 1863 break; 1864 case CON: 1865 case STRING: 1866 break; 1867 case CALL:; 1868 const function_call *call = tn->u.call; 1869 for (size_t i = 0, n = call->args_len; i < n; i++) 1870 use(call->args[i]); 1871 break; 1872 default: 1873 lint_assert(has_operands(tn)); 1874 use(tn->u.ops.left); 1875 if (is_binary(tn)) 1876 use(tn->u.ops.right); 1877 } 1878 } 1879 1880 /* 1881 * Create a tree node for a binary operator and its two operands. Also called 1882 * for unary operators; in that case rn is NULL. 1883 * 1884 * Function calls, sizeof and casts are handled elsewhere. 1885 */ 1886 tnode_t * 1887 build_binary(tnode_t *ln, op_t op, bool sys, tnode_t *rn) 1888 { 1889 const mod_t *mp = &modtab[op]; 1890 1891 /* If there was an error in one of the operands, return. */ 1892 if (ln == NULL || (mp->m_binary && rn == NULL)) 1893 return NULL; 1894 1895 if (mp->m_value_context || mp->m_compares_with_zero) 1896 ln = cconv(ln); 1897 if (mp->m_binary && op != ARROW && op != POINT) 1898 rn = cconv(rn); 1899 1900 if (mp->m_comparison) 1901 check_integer_comparison(op, ln, rn); 1902 1903 if (mp->m_value_context || mp->m_compares_with_zero) 1904 ln = promote(op, false, ln); 1905 if (mp->m_binary && op != ARROW && op != POINT && 1906 op != ASSIGN && op != RETURN && op != INIT) 1907 rn = promote(op, false, rn); 1908 1909 if (mp->m_warn_if_left_unsigned_in_c90 && 1910 ln->tn_op == CON && ln->u.value.v_unsigned_since_c90) { 1911 /* C90 treats constant as unsigned, op '%s' */ 1912 warning(218, op_name(op)); 1913 ln->u.value.v_unsigned_since_c90 = false; 1914 } 1915 if (mp->m_warn_if_right_unsigned_in_c90 && 1916 rn->tn_op == CON && rn->u.value.v_unsigned_since_c90) { 1917 /* C90 treats constant as unsigned, op '%s' */ 1918 warning(218, op_name(op)); 1919 rn->u.value.v_unsigned_since_c90 = false; 1920 } 1921 1922 if (mp->m_balance_operands || (!allow_c90 && (op == SHL || op == SHR))) 1923 balance(op, &ln, &rn); 1924 1925 if (!typeok(op, 0, ln, rn)) 1926 return NULL; 1927 1928 tnode_t *ntn; 1929 switch (op) { 1930 case POINT: 1931 case ARROW: 1932 ntn = build_struct_access(op, sys, ln, rn); 1933 break; 1934 case NOT: 1935 if (ln->tn_op == ASSIGN && ln->u.ops.right->tn_op == CON) { 1936 /* constant assignment of type '%s' in operand ... */ 1937 warning(382, type_name(ln->tn_type), 1938 is_nonzero_val(&ln->u.ops.right->u.value) 1939 ? "true" : "false"); 1940 } 1941 ntn = build_op(op, sys, gettyp(Tflag ? BOOL : INT), ln, NULL); 1942 break; 1943 case INCAFT: 1944 case DECAFT: 1945 case INCBEF: 1946 case DECBEF: 1947 ntn = build_prepost_incdec(op, sys, ln); 1948 break; 1949 case ADDR: 1950 ntn = build_address(sys, ln, false); 1951 break; 1952 case INDIR: 1953 ntn = build_op(INDIR, sys, ln->tn_type->t_subt, ln, NULL); 1954 break; 1955 case PLUS: 1956 case MINUS: 1957 ntn = build_plus_minus(op, sys, ln, rn); 1958 break; 1959 case SHL: 1960 case SHR: 1961 ntn = build_bit_shift(op, sys, ln, rn); 1962 break; 1963 case COLON: 1964 ntn = build_colon(sys, ln, rn); 1965 break; 1966 case ASSIGN: 1967 case MULASS: 1968 case DIVASS: 1969 case MODASS: 1970 case ADDASS: 1971 case SUBASS: 1972 case SHLASS: 1973 case SHRASS: 1974 case ANDASS: 1975 case XORASS: 1976 case ORASS: 1977 case RETURN: 1978 case INIT: 1979 ntn = build_assignment(op, sys, ln, rn); 1980 break; 1981 case COMMA: 1982 /* comma operator with types '%s' and '%s' */ 1983 query_message(12, 1984 type_name(ln->tn_type), type_name(rn->tn_type)); 1985 /* FALLTHROUGH */ 1986 case QUEST: 1987 ntn = build_op(op, sys, rn->tn_type, ln, rn); 1988 break; 1989 case REAL: 1990 case IMAG: 1991 ntn = build_real_imag(op, sys, ln); 1992 break; 1993 default: 1994 lint_assert(mp->m_binary == (rn != NULL)); 1995 type_t *rettp = mp->m_returns_bool 1996 ? gettyp(Tflag ? BOOL : INT) : ln->tn_type; 1997 ntn = build_op(op, sys, rettp, ln, rn); 1998 break; 1999 } 2000 2001 if (ntn == NULL) 2002 return NULL; 2003 2004 if (mp->m_possible_precedence_confusion) 2005 check_precedence_confusion(ntn); 2006 2007 if (hflag && !suppress_constcond && 2008 mp->m_compares_with_zero && 2009 (ln->tn_op == CON || 2010 (mp->m_binary && op != QUEST && rn->tn_op == CON)) && 2011 /* XXX: rn->tn_system_dependent should be checked as well */ 2012 !ln->tn_system_dependent) 2013 /* constant in conditional context */ 2014 warning(161); 2015 2016 if (mp->m_fold_constant_operands && ln->tn_op == CON) { 2017 if (!mp->m_binary || rn->tn_op == CON) { 2018 if (mp->m_compares_with_zero) 2019 ntn = fold_constant_compare_zero(ntn); 2020 else if (is_floating(ntn->tn_type->t_tspec)) 2021 ntn = fold_constant_floating(ntn); 2022 else 2023 ntn = fold_constant_integer(ntn); 2024 } else if (op == QUEST) { 2025 lint_assert(has_operands(rn)); 2026 use(ln->u.value.u.integer != 0 2027 ? rn->u.ops.right : rn->u.ops.left); 2028 ntn = ln->u.value.u.integer != 0 2029 ? rn->u.ops.left : rn->u.ops.right; 2030 } 2031 } 2032 2033 return ntn; 2034 } 2035 2036 tnode_t * 2037 build_unary(op_t op, bool sys, tnode_t *tn) 2038 { 2039 return build_binary(tn, op, sys, NULL); 2040 } 2041 2042 static bool 2043 are_members_compatible(const sym_t *a, const sym_t *b) 2044 { 2045 if (a->u.s_member.sm_offset_in_bits != b->u.s_member.sm_offset_in_bits) 2046 return false; 2047 2048 const type_t *atp = a->s_type; 2049 const type_t *btp = b->s_type; 2050 bool w = false; 2051 if (!types_compatible(atp, btp, false, false, &w) && !w) 2052 return false; 2053 if (a->s_bitfield != b->s_bitfield) 2054 return false; 2055 if (a->s_bitfield) { 2056 if (atp->t_bit_field_width != btp->t_bit_field_width) 2057 return false; 2058 if (atp->t_bit_field_offset != btp->t_bit_field_offset) 2059 return false; 2060 } 2061 return true; 2062 } 2063 2064 /* 2065 * Return whether all struct/union members with the same name have the same 2066 * type and offset. 2067 */ 2068 static bool 2069 all_members_compatible(const sym_t *msym) 2070 { 2071 for (const sym_t *csym = msym; 2072 csym != NULL; csym = csym->s_symtab_next) { 2073 if (!is_member(csym)) 2074 continue; 2075 if (strcmp(msym->s_name, csym->s_name) != 0) 2076 continue; 2077 2078 for (const sym_t *sym = csym->s_symtab_next; 2079 sym != NULL; sym = sym->s_symtab_next) { 2080 if (is_member(sym) 2081 && strcmp(csym->s_name, sym->s_name) == 0 2082 && !are_members_compatible(csym, sym)) 2083 return false; 2084 } 2085 } 2086 return true; 2087 } 2088 2089 sym_t * 2090 find_member(const struct_or_union *sou, const char *name) 2091 { 2092 for (sym_t *mem = sou->sou_first_member; 2093 mem != NULL; mem = mem->s_next) { 2094 lint_assert(is_member(mem)); 2095 lint_assert(mem->u.s_member.sm_containing_type == sou); 2096 if (strcmp(mem->s_name, name) == 0) 2097 return mem; 2098 } 2099 2100 for (sym_t *mem = sou->sou_first_member; 2101 mem != NULL; mem = mem->s_next) { 2102 if (is_struct_or_union(mem->s_type->t_tspec) 2103 && mem->s_name == unnamed) { 2104 sym_t *nested_mem = 2105 find_member(mem->s_type->u.sou, name); 2106 if (nested_mem != NULL) 2107 return nested_mem; 2108 } 2109 } 2110 return NULL; 2111 } 2112 2113 /* 2114 * Remove the member if it was unknown until now, which means 2115 * that no defined struct or union has a member with the same name. 2116 */ 2117 static void 2118 remove_unknown_member(tnode_t *tn, sym_t *msym) 2119 { 2120 /* type '%s' does not have member '%s' */ 2121 error(101, type_name(tn->tn_type), msym->s_name); 2122 symtab_remove_forever(msym); 2123 msym->s_kind = SK_MEMBER; 2124 msym->s_scl = STRUCT_MEMBER; 2125 2126 struct_or_union *sou = expr_zero_alloc(sizeof(*sou), 2127 "struct_or_union"); 2128 sou->sou_tag = expr_zero_alloc(sizeof(*sou->sou_tag), "sym"); 2129 sou->sou_tag->s_name = unnamed; 2130 2131 msym->u.s_member.sm_containing_type = sou; 2132 /* 2133 * The member sm_offset_in_bits is not needed here since this symbol 2134 * can only be used for error reporting. 2135 */ 2136 } 2137 2138 /* 2139 * Returns a symbol which has the same name as 'msym' and is a member of the 2140 * struct or union specified by 'tn'. 2141 */ 2142 static sym_t * 2143 struct_or_union_member(tnode_t *tn, op_t op, sym_t *msym) 2144 { 2145 2146 /* Determine the tag type of which msym is expected to be a member. */ 2147 const type_t *tp = NULL; 2148 if (op == POINT && is_struct_or_union(tn->tn_type->t_tspec)) 2149 tp = tn->tn_type; 2150 if (op == ARROW && tn->tn_type->t_tspec == PTR 2151 && is_struct_or_union(tn->tn_type->t_subt->t_tspec)) 2152 tp = tn->tn_type->t_subt; 2153 struct_or_union *sou = tp != NULL ? tp->u.sou : NULL; 2154 2155 if (sou != NULL) { 2156 sym_t *nested_mem = find_member(sou, msym->s_name); 2157 if (nested_mem != NULL) 2158 return nested_mem; 2159 } 2160 2161 if (msym->s_scl == NO_SCL) { 2162 remove_unknown_member(tn, msym); 2163 return msym; 2164 } 2165 2166 bool eq = all_members_compatible(msym); 2167 2168 /* 2169 * Now handle the case in which the left operand refers really to a 2170 * struct/union, but the right operand is not member of it. 2171 */ 2172 if (sou != NULL) { 2173 if (eq && !allow_c90) 2174 /* illegal use of member '%s' */ 2175 warning(102, msym->s_name); 2176 else 2177 /* illegal use of member '%s' */ 2178 error(102, msym->s_name); 2179 return msym; 2180 } 2181 2182 if (eq) { 2183 if (op == POINT) { 2184 if (!allow_c90) 2185 /* left operand of '.' must be struct ... */ 2186 warning(103, type_name(tn->tn_type)); 2187 else 2188 /* left operand of '.' must be struct ... */ 2189 error(103, type_name(tn->tn_type)); 2190 } else { 2191 if (!allow_c90 && tn->tn_type->t_tspec == PTR) 2192 /* left operand of '->' must be pointer ... */ 2193 warning(104, type_name(tn->tn_type)); 2194 else 2195 /* left operand of '->' must be pointer ... */ 2196 error(104, type_name(tn->tn_type)); 2197 } 2198 } else { 2199 if (!allow_c90) 2200 /* non-unique member requires struct/union %s */ 2201 error(105, op == POINT ? "object" : "pointer"); 2202 else 2203 /* unacceptable operand of '%s' */ 2204 error(111, op_name(op)); 2205 } 2206 2207 return msym; 2208 } 2209 2210 tnode_t * 2211 build_member_access(tnode_t *ln, op_t op, bool sys, sbuf_t *member) 2212 { 2213 sym_t *msym; 2214 2215 if (ln == NULL) 2216 return NULL; 2217 2218 if (op == ARROW) 2219 /* must do this before struct_or_union_member is called */ 2220 ln = cconv(ln); 2221 msym = struct_or_union_member(ln, op, getsym(member)); 2222 return build_binary(ln, op, sys, build_name(msym, false)); 2223 } 2224 2225 /* 2226 * Perform class conversions. 2227 * 2228 * Arrays of type T are converted into pointers to type T. 2229 * Functions are converted to pointers to functions. 2230 * Lvalues are converted to rvalues. 2231 * 2232 * C99 6.3 "Conversions" 2233 * C99 6.3.2 "Other operands" 2234 * C99 6.3.2.1 "Lvalues, arrays, and function designators" 2235 */ 2236 tnode_t * 2237 cconv(tnode_t *tn) 2238 { 2239 if (tn->tn_type->t_tspec == ARRAY) { 2240 if (!tn->tn_lvalue) { 2241 /* XXX print correct operator */ 2242 /* %soperand of '%s' must be lvalue */ 2243 gnuism(114, "", op_name(ADDR)); 2244 } 2245 tn = build_op(ADDR, tn->tn_sys, 2246 expr_derive_type(tn->tn_type->t_subt, PTR), tn, NULL); 2247 } 2248 2249 if (tn->tn_type->t_tspec == FUNC) 2250 tn = build_address(tn->tn_sys, tn, true); 2251 2252 if (tn->tn_lvalue) { 2253 type_t *tp = expr_dup_type(tn->tn_type); 2254 /* C99 6.3.2.1p2 sentence 2 says to remove the qualifiers. */ 2255 tp->t_const = tp->t_volatile = false; 2256 tn = build_op(LOAD, tn->tn_sys, tp, tn, NULL); 2257 } 2258 2259 return tn; 2260 } 2261 2262 const tnode_t * 2263 before_conversion(const tnode_t *tn) 2264 { 2265 while (tn->tn_op == CVT && !tn->tn_cast) 2266 tn = tn->u.ops.left; 2267 return tn; 2268 } 2269 2270 /* 2271 * Most errors required by C90 are reported in struct_or_union_member(). 2272 * Here we only check for totally wrong things. 2273 */ 2274 static bool 2275 typeok_point(const tnode_t *ln, const type_t *ltp, tspec_t lt) 2276 { 2277 if (is_struct_or_union(lt)) 2278 return true; 2279 2280 if (lt == FUNC || lt == VOID || ltp->t_bitfield) 2281 goto wrong; 2282 2283 /* 2284 * Some C dialects from before C90 tolerated any lvalue on the 2285 * left-hand side of the '.' operator, allowing things like 'char 2286 * st[100]; st.st_mtime', assuming that the member 'st_mtime' only 2287 * occurred in a single struct; see typeok_arrow. 2288 */ 2289 if (ln->tn_lvalue) 2290 return true; 2291 2292 wrong: 2293 /* With allow_c90 we already got an error */ 2294 if (!allow_c90) 2295 /* unacceptable operand of '%s' */ 2296 error(111, op_name(POINT)); 2297 2298 return false; 2299 } 2300 2301 static bool 2302 typeok_arrow(tspec_t lt) 2303 { 2304 /* 2305 * C1978 Appendix A 14.1 says: <quote>In fact, any lvalue is allowed 2306 * before '.', and that lvalue is then assumed to have the form of the 2307 * structure of which the name of the right is a member. [...] Such 2308 * constructions are non-portable.</quote> 2309 */ 2310 if (lt == PTR || (!allow_c90 && is_integer(lt))) 2311 return true; 2312 2313 /* With allow_c90 we already got an error */ 2314 if (!allow_c90) 2315 /* unacceptable operand of '%s' */ 2316 error(111, op_name(ARROW)); 2317 return false; 2318 } 2319 2320 static bool 2321 typeok_incdec(op_t op, const tnode_t *tn, const type_t *tp) 2322 { 2323 /* operand has scalar type (checked in typeok) */ 2324 if (!tn->tn_lvalue) { 2325 if (tn->tn_op == CVT && tn->tn_cast && 2326 tn->u.ops.left->tn_op == LOAD) 2327 /* a cast does not yield an lvalue */ 2328 error(163); 2329 /* %soperand of '%s' must be lvalue */ 2330 error(114, "", op_name(op)); 2331 return false; 2332 } 2333 if (tp->t_const && allow_c90) 2334 /* %soperand of '%s' must be modifiable lvalue */ 2335 warning(115, "", op_name(op)); 2336 return true; 2337 } 2338 2339 static bool 2340 typeok_address(op_t op, const tnode_t *tn, const type_t *tp, tspec_t t) 2341 { 2342 if (t == ARRAY || t == FUNC) { 2343 /* ok, a warning comes later (in build_address()) */ 2344 } else if (!tn->tn_lvalue) { 2345 if (tn->tn_op == CVT && tn->tn_cast && 2346 tn->u.ops.left->tn_op == LOAD) 2347 /* a cast does not yield an lvalue */ 2348 error(163); 2349 /* %soperand of '%s' must be lvalue */ 2350 error(114, "", op_name(op)); 2351 return false; 2352 } else if (is_scalar(t)) { 2353 if (tp->t_bitfield) { 2354 /* cannot take address of bit-field */ 2355 error(112); 2356 return false; 2357 } 2358 } else if (t != STRUCT && t != UNION) { 2359 /* unacceptable operand of '%s' */ 2360 error(111, op_name(op)); 2361 return false; 2362 } 2363 if (tn->tn_op == NAME && tn->u.sym->s_register) { 2364 /* cannot take address of register '%s' */ 2365 error(113, tn->u.sym->s_name); 2366 return false; 2367 } 2368 return true; 2369 } 2370 2371 static bool 2372 typeok_indir(const type_t *tp, tspec_t t) 2373 { 2374 2375 if (t != PTR) { 2376 /* cannot dereference non-pointer type '%s' */ 2377 error(96, type_name(tp)); 2378 return false; 2379 } 2380 return true; 2381 } 2382 2383 static void 2384 warn_incompatible_types(op_t op, 2385 const type_t *ltp, tspec_t lt, 2386 const type_t *rtp, tspec_t rt) 2387 { 2388 bool binary = modtab[op].m_binary; 2389 2390 if (lt == VOID || (binary && rt == VOID)) { 2391 /* void type illegal in expression */ 2392 error(109); 2393 } else if (op == ASSIGN) 2394 /* cannot assign to '%s' from '%s' */ 2395 error(171, type_name(ltp), type_name(rtp)); 2396 else if (binary) 2397 /* operands of '%s' have incompatible types '%s' and '%s' */ 2398 error(107, op_name(op), type_name(ltp), type_name(rtp)); 2399 else { 2400 lint_assert(rt == NO_TSPEC); 2401 /* operand of '%s' has invalid type '%s' */ 2402 error(108, op_name(op), type_name(ltp)); 2403 } 2404 } 2405 2406 static bool 2407 typeok_plus(op_t op, 2408 const type_t *ltp, tspec_t lt, 2409 const type_t *rtp, tspec_t rt) 2410 { 2411 /* operands have scalar types (checked in typeok) */ 2412 if ((lt == PTR && !is_integer(rt)) || (rt == PTR && !is_integer(lt))) { 2413 warn_incompatible_types(op, ltp, lt, rtp, rt); 2414 return false; 2415 } 2416 return true; 2417 } 2418 2419 static bool 2420 typeok_minus(op_t op, 2421 const type_t *ltp, tspec_t lt, 2422 const type_t *rtp, tspec_t rt) 2423 { 2424 /* operands have scalar types (checked in typeok) */ 2425 if ((lt == PTR && rt != PTR && !is_integer(rt)) || 2426 (lt != PTR && rt == PTR)) { 2427 warn_incompatible_types(op, ltp, lt, rtp, rt); 2428 return false; 2429 } 2430 if (lt == PTR && rt == PTR && 2431 !types_compatible(ltp->t_subt, rtp->t_subt, true, false, NULL)) { 2432 /* illegal pointer subtraction */ 2433 error(116); 2434 } 2435 return true; 2436 } 2437 2438 static void 2439 typeok_shr(op_t op, 2440 const tnode_t *ln, tspec_t lt, 2441 const tnode_t *rn, tspec_t rt) 2442 { 2443 tspec_t olt = before_conversion(ln)->tn_type->t_tspec; 2444 tspec_t ort = before_conversion(rn)->tn_type->t_tspec; 2445 2446 /* operands have integer types (checked in typeok) */ 2447 if (pflag && !is_uinteger(olt)) { 2448 integer_constraints lc = ic_expr(ln); 2449 if (!ic_maybe_signed(ln->tn_type, &lc)) 2450 return; 2451 2452 if (ln->tn_op != CON) 2453 /* bitwise '%s' on signed value possibly nonportable */ 2454 warning(117, op_name(op)); 2455 else if (ln->u.value.u.integer < 0) 2456 /* bitwise '%s' on signed value nonportable */ 2457 warning(120, op_name(op)); 2458 } else if (allow_trad && allow_c90 && 2459 !is_uinteger(olt) && is_uinteger(ort)) { 2460 /* The left operand would become unsigned in traditional C. */ 2461 if (hflag && (ln->tn_op != CON || ln->u.value.u.integer < 0)) { 2462 /* semantics of '%s' change in C90; use ... */ 2463 warning(118, op_name(op)); 2464 } 2465 } else if (allow_trad && allow_c90 && 2466 !is_uinteger(olt) && !is_uinteger(ort) && 2467 portable_rank_cmp(lt, rt) < 0) { 2468 /* 2469 * In traditional C, the left operand would be extended 2470 * (possibly sign-extended) and then shifted. 2471 */ 2472 if (hflag && (ln->tn_op != CON || ln->u.value.u.integer < 0)) { 2473 /* semantics of '%s' change in C90; use ... */ 2474 warning(118, op_name(op)); 2475 } 2476 } 2477 } 2478 2479 static void 2480 typeok_shl(op_t op, tspec_t lt, tspec_t rt) 2481 { 2482 /* 2483 * C90 does not perform balancing for shift operations, but traditional 2484 * C does. If the width of the right operand is greater than the width 2485 * of the left operand, then in traditional C the left operand would be 2486 * extended to the width of the right operand. For SHL this may result 2487 * in different results. 2488 */ 2489 if (portable_rank_cmp(lt, rt) < 0) { 2490 /* 2491 * XXX If both operands are constant, make sure that there is 2492 * really a difference between C90 and traditional C. 2493 */ 2494 if (hflag && allow_trad && allow_c90) 2495 /* semantics of '%s' change in C90; use ... */ 2496 warning(118, op_name(op)); 2497 } 2498 } 2499 2500 static void 2501 typeok_shift(const type_t *ltp, tspec_t lt, const tnode_t *rn, tspec_t rt) 2502 { 2503 if (rn->tn_op != CON) 2504 return; 2505 2506 if (!is_uinteger(rt) && rn->u.value.u.integer < 0) 2507 /* negative shift */ 2508 warning(121); 2509 else if ((uint64_t)rn->u.value.u.integer == size_in_bits(lt)) 2510 /* shift amount %u equals bit-size of '%s' */ 2511 warning(267, (unsigned)rn->u.value.u.integer, type_name(ltp)); 2512 else if ((uint64_t)rn->u.value.u.integer > size_in_bits(lt)) { 2513 /* shift amount %llu is greater than bit-size %llu of '%s' */ 2514 warning(122, (unsigned long long)rn->u.value.u.integer, 2515 (unsigned long long)size_in_bits(lt), 2516 tspec_name(lt)); 2517 } 2518 } 2519 2520 static bool 2521 is_typeok_eq(const tnode_t *ln, tspec_t lt, const tnode_t *rn, tspec_t rt) 2522 { 2523 if (lt == PTR && is_null_pointer(rn)) 2524 return true; 2525 if (rt == PTR && is_null_pointer(ln)) 2526 return true; 2527 return false; 2528 } 2529 2530 static void 2531 warn_incompatible_pointers(op_t op, const type_t *ltp, const type_t *rtp) 2532 { 2533 lint_assert(ltp->t_tspec == PTR); 2534 lint_assert(rtp->t_tspec == PTR); 2535 2536 tspec_t lt = ltp->t_subt->t_tspec; 2537 tspec_t rt = rtp->t_subt->t_tspec; 2538 2539 if (is_struct_or_union(lt) && is_struct_or_union(rt)) { 2540 if (op == RETURN) 2541 /* illegal structure pointer combination */ 2542 warning(244); 2543 else { 2544 /* incompatible structure pointers: '%s' '%s' '%s' */ 2545 warning(245, type_name(ltp), 2546 op_name(op), type_name(rtp)); 2547 } 2548 } else { 2549 if (op == RETURN) 2550 /* illegal combination of '%s' and '%s' */ 2551 warning(184, type_name(ltp), type_name(rtp)); 2552 else { 2553 /* illegal combination of '%s' and '%s', op '%s' */ 2554 warning(124, 2555 type_name(ltp), type_name(rtp), op_name(op)); 2556 } 2557 } 2558 } 2559 2560 static void 2561 check_pointer_comparison(op_t op, const tnode_t *ln, const tnode_t *rn) 2562 { 2563 type_t *ltp = ln->tn_type, *rtp = rn->tn_type; 2564 tspec_t lst = ltp->t_subt->t_tspec, rst = rtp->t_subt->t_tspec; 2565 2566 if (lst == VOID || rst == VOID) { 2567 /* TODO: C99 behaves like C90 here. */ 2568 if (!allow_trad && !allow_c99 && 2569 (lst == FUNC || rst == FUNC)) { 2570 /* (void *)0 is already handled in typeok() */ 2571 const char *lsts, *rsts; 2572 *(lst == FUNC ? &lsts : &rsts) = "function pointer"; 2573 *(lst == VOID ? &lsts : &rsts) = "'void *'"; 2574 /* C90 or later forbid comparison of %s with %s */ 2575 warning(274, lsts, rsts); 2576 } 2577 return; 2578 } 2579 2580 if (!types_compatible(ltp->t_subt, rtp->t_subt, true, false, NULL)) { 2581 warn_incompatible_pointers(op, ltp, rtp); 2582 return; 2583 } 2584 2585 if (lst == FUNC && rst == FUNC) { 2586 /* TODO: C99 behaves like C90 here, see C99 6.5.8p2. */ 2587 if (!allow_trad && !allow_c99 && op != EQ && op != NE) 2588 /* pointers to functions can only be compared ... */ 2589 warning(125); 2590 } 2591 } 2592 2593 static bool 2594 typeok_compare(op_t op, 2595 const tnode_t *ln, const type_t *ltp, tspec_t lt, 2596 const tnode_t *rn, const type_t *rtp, tspec_t rt) 2597 { 2598 if (lt == PTR && rt == PTR) { 2599 check_pointer_comparison(op, ln, rn); 2600 return true; 2601 } 2602 2603 if (lt != PTR && rt != PTR) 2604 return true; 2605 2606 if (!is_integer(lt) && !is_integer(rt)) { 2607 warn_incompatible_types(op, ltp, lt, rtp, rt); 2608 return false; 2609 } 2610 2611 const char *lx = lt == PTR ? "pointer" : "integer"; 2612 const char *rx = rt == PTR ? "pointer" : "integer"; 2613 /* illegal combination of %s '%s' and %s '%s', op '%s' */ 2614 warning(123, lx, type_name(ltp), rx, type_name(rtp), op_name(op)); 2615 return true; 2616 } 2617 2618 static bool 2619 typeok_quest(tspec_t lt, const tnode_t *rn) 2620 { 2621 if (!is_scalar(lt)) { 2622 /* first operand of '?' must have scalar type */ 2623 error(170); 2624 return false; 2625 } 2626 lint_assert(before_conversion(rn)->tn_op == COLON); 2627 return true; 2628 } 2629 2630 static void 2631 typeok_colon_pointer(const type_t *ltp, const type_t *rtp) 2632 { 2633 type_t *lstp = ltp->t_subt; 2634 type_t *rstp = rtp->t_subt; 2635 tspec_t lst = lstp->t_tspec; 2636 tspec_t rst = rstp->t_tspec; 2637 2638 if ((lst == VOID && rst == FUNC) || (lst == FUNC && rst == VOID)) { 2639 /* (void *)0 is handled in typeok_colon */ 2640 /* TODO: C99 behaves like C90 here. */ 2641 if (!allow_trad && !allow_c99) 2642 /* conversion of %s to %s requires a cast, op %s */ 2643 warning(305, "function pointer", "'void *'", 2644 op_name(COLON)); 2645 return; 2646 } 2647 2648 if (pointer_types_are_compatible(lstp, rstp, true)) 2649 return; 2650 if (!types_compatible(lstp, rstp, true, false, NULL)) 2651 warn_incompatible_pointers(COLON, ltp, rtp); 2652 } 2653 2654 static bool 2655 typeok_colon(const tnode_t *ln, const type_t *ltp, tspec_t lt, 2656 const tnode_t *rn, const type_t *rtp, tspec_t rt) 2657 { 2658 2659 if (is_arithmetic(lt) && is_arithmetic(rt)) 2660 return true; 2661 if (lt == BOOL && rt == BOOL) 2662 return true; 2663 2664 if (lt == STRUCT && rt == STRUCT && ltp->u.sou == rtp->u.sou) 2665 return true; 2666 if (lt == UNION && rt == UNION && ltp->u.sou == rtp->u.sou) 2667 return true; 2668 2669 if (lt == PTR && is_null_pointer(rn)) 2670 return true; 2671 if (rt == PTR && is_null_pointer(ln)) 2672 return true; 2673 2674 if ((lt == PTR && is_integer(rt)) || (is_integer(lt) && rt == PTR)) { 2675 const char *lx = lt == PTR ? "pointer" : "integer"; 2676 const char *rx = rt == PTR ? "pointer" : "integer"; 2677 /* illegal combination of %s '%s' and %s '%s', op '%s' */ 2678 warning(123, lx, type_name(ltp), 2679 rx, type_name(rtp), op_name(COLON)); 2680 return true; 2681 } 2682 2683 if (lt == VOID || rt == VOID) { 2684 if (lt != VOID || rt != VOID) 2685 /* incompatible types '%s' and '%s' in conditional */ 2686 warning(126, type_name(ltp), type_name(rtp)); 2687 return true; 2688 } 2689 2690 if (lt == PTR && rt == PTR) { 2691 typeok_colon_pointer(ltp, rtp); 2692 return true; 2693 } 2694 2695 /* incompatible types '%s' and '%s' in conditional */ 2696 error(126, type_name(ltp), type_name(rtp)); 2697 return false; 2698 } 2699 2700 static bool 2701 has_constant_member(const type_t *tp) 2702 { 2703 lint_assert(is_struct_or_union(tp->t_tspec)); 2704 2705 for (sym_t *m = tp->u.sou->sou_first_member; 2706 m != NULL; m = m->s_next) { 2707 const type_t *mtp = m->s_type; 2708 if (mtp->t_const) 2709 return true; 2710 if (is_struct_or_union(mtp->t_tspec) && 2711 has_constant_member(mtp)) 2712 return true; 2713 } 2714 return false; 2715 } 2716 2717 static bool 2718 typeok_assign(op_t op, const tnode_t *ln, const type_t *ltp, tspec_t lt) 2719 { 2720 if (op == RETURN || op == INIT || op == FARG) 2721 return true; 2722 2723 if (!ln->tn_lvalue) { 2724 if (ln->tn_op == CVT && ln->tn_cast && 2725 ln->u.ops.left->tn_op == LOAD) 2726 /* a cast does not yield an lvalue */ 2727 error(163); 2728 /* %soperand of '%s' must be lvalue */ 2729 error(114, "left ", op_name(op)); 2730 return false; 2731 } else if (ltp->t_const 2732 || (is_struct_or_union(lt) && has_constant_member(ltp))) { 2733 if (allow_c90) 2734 /* %soperand of '%s' must be modifiable lvalue */ 2735 warning(115, "left ", op_name(op)); 2736 } 2737 return true; 2738 } 2739 2740 static bool 2741 typeok_scalar(op_t op, const mod_t *mp, 2742 const type_t *ltp, tspec_t lt, 2743 const type_t *rtp, tspec_t rt) 2744 { 2745 if (mp->m_takes_bool && lt == BOOL && rt == BOOL) 2746 return true; 2747 if (mp->m_requires_integer) { 2748 if (!is_integer(lt) || (mp->m_binary && !is_integer(rt))) { 2749 warn_incompatible_types(op, ltp, lt, rtp, rt); 2750 return false; 2751 } 2752 } else if (mp->m_requires_integer_or_complex) { 2753 if ((!is_integer(lt) && !is_complex(lt)) || 2754 (mp->m_binary && (!is_integer(rt) && !is_complex(rt)))) { 2755 warn_incompatible_types(op, ltp, lt, rtp, rt); 2756 return false; 2757 } 2758 } else if (mp->m_requires_scalar) { 2759 if (!is_scalar(lt) || (mp->m_binary && !is_scalar(rt))) { 2760 warn_incompatible_types(op, ltp, lt, rtp, rt); 2761 return false; 2762 } 2763 } else if (mp->m_requires_arith) { 2764 if (!is_arithmetic(lt) || 2765 (mp->m_binary && !is_arithmetic(rt))) { 2766 warn_incompatible_types(op, ltp, lt, rtp, rt); 2767 return false; 2768 } 2769 } 2770 return true; 2771 } 2772 2773 static void 2774 check_assign_void_pointer(op_t op, int arg, 2775 tspec_t lt, tspec_t lst, 2776 tspec_t rt, tspec_t rst) 2777 { 2778 2779 if (!(lt == PTR && rt == PTR && (lst == VOID || rst == VOID))) 2780 return; 2781 /* two pointers, at least one pointer to void */ 2782 2783 /* TODO: C99 behaves like C90 here. */ 2784 if (!(!allow_trad && !allow_c99 && (lst == FUNC || rst == FUNC))) 2785 return; 2786 /* comb. of ptr to func and ptr to void */ 2787 2788 const char *lts, *rts; 2789 *(lst == FUNC ? <s : &rts) = "function pointer"; 2790 *(lst == VOID ? <s : &rts) = "'void *'"; 2791 2792 switch (op) { 2793 case INIT: 2794 case RETURN: 2795 /* conversion of %s to %s requires a cast */ 2796 warning(303, rts, lts); 2797 break; 2798 case FARG: 2799 /* conversion of %s to %s requires a cast, arg #%d */ 2800 warning(304, rts, lts, arg); 2801 break; 2802 default: 2803 /* conversion of %s to %s requires a cast, op %s */ 2804 warning(305, rts, lts, op_name(op)); 2805 break; 2806 } 2807 } 2808 2809 static bool 2810 is_direct_function_call(const tnode_t *tn, const char **out_name) 2811 { 2812 2813 if (tn->tn_op == CALL 2814 && tn->u.call->func->tn_op == ADDR 2815 && tn->u.call->func->u.ops.left->tn_op == NAME) { 2816 *out_name = tn->u.call->func->u.ops.left->u.sym->s_name; 2817 return true; 2818 } 2819 return false; 2820 } 2821 2822 static bool 2823 is_unconst_function(const char *name) 2824 { 2825 2826 return strcmp(name, "memchr") == 0 || 2827 strcmp(name, "strchr") == 0 || 2828 strcmp(name, "strpbrk") == 0 || 2829 strcmp(name, "strrchr") == 0 || 2830 strcmp(name, "strstr") == 0; 2831 } 2832 2833 static bool 2834 is_const_char_pointer(const tnode_t *tn) 2835 { 2836 /* 2837 * For traditional reasons, C99 6.4.5p5 defines that string literals 2838 * have type 'char[]'. They are often implicitly converted to 'char 2839 * *', for example when they are passed as function arguments. 2840 * 2841 * C99 6.4.5p6 further defines that modifying a string that is 2842 * constructed from a string literal invokes undefined behavior. 2843 * 2844 * Out of these reasons, string literals are treated as 'effectively 2845 * const' here. 2846 */ 2847 if (tn->tn_op == CVT && 2848 tn->u.ops.left->tn_op == ADDR && 2849 tn->u.ops.left->u.ops.left->tn_op == STRING) 2850 return true; 2851 2852 const type_t *tp = before_conversion(tn)->tn_type; 2853 return tp->t_tspec == PTR && 2854 tp->t_subt->t_tspec == CHAR && 2855 tp->t_subt->t_const; 2856 } 2857 2858 static bool 2859 is_const_pointer(const tnode_t *tn) 2860 { 2861 const type_t *tp = before_conversion(tn)->tn_type; 2862 return tp->t_tspec == PTR && tp->t_subt->t_const; 2863 } 2864 2865 static void 2866 check_unconst_function(const type_t *lstp, const tnode_t *rn) 2867 { 2868 const char *function_name; 2869 2870 if (lstp->t_tspec == CHAR && !lstp->t_const && 2871 is_direct_function_call(rn, &function_name) && 2872 is_unconst_function(function_name) && 2873 rn->u.call->args_len >= 1 && 2874 is_const_char_pointer(rn->u.call->args[0])) { 2875 /* call to '%s' effectively discards 'const' from argument */ 2876 warning(346, function_name); 2877 } 2878 2879 if (!lstp->t_const && 2880 is_direct_function_call(rn, &function_name) && 2881 strcmp(function_name, "bsearch") == 0 && 2882 rn->u.call->args_len >= 2 && 2883 is_const_pointer(rn->u.call->args[1])) { 2884 /* call to '%s' effectively discards 'const' from argument */ 2885 warning(346, function_name); 2886 } 2887 } 2888 2889 static bool 2890 check_assign_void_pointer_compat(op_t op, int arg, 2891 tspec_t lt, 2892 const type_t *lstp, tspec_t lst, 2893 const tnode_t *rn, 2894 const type_t *rtp, tspec_t rt, 2895 const type_t *rstp, tspec_t rst) 2896 { 2897 if (!(lt == PTR && rt == PTR && (lst == VOID || rst == VOID || 2898 types_compatible(lstp, rstp, 2899 true, false, NULL)))) 2900 return false; 2901 2902 /* compatible pointer types (qualifiers ignored) */ 2903 char qualifiers[32]; 2904 snprintf(qualifiers, sizeof(qualifiers), "%s%s", 2905 !lstp->t_const && rstp->t_const ? " const" : "", 2906 !lstp->t_volatile && rstp->t_volatile ? " volatile" : ""); 2907 if (allow_c90 && qualifiers[0] != '\0') { 2908 switch (op) { 2909 case INIT: 2910 case RETURN: 2911 /* '%s' discards '%s' from '%s' */ 2912 warning(182, op_name(op), 2913 qualifiers + 1, type_name(rtp)); 2914 break; 2915 case FARG: 2916 /* passing '%s' to argument %d discards '%s' */ 2917 warning(383, type_name(rtp), arg, qualifiers + 1); 2918 break; 2919 default: 2920 /* operator '%s' discards '%s' from '%s' */ 2921 warning(128, op_name(op), 2922 qualifiers + 1, type_name(rtp)); 2923 break; 2924 } 2925 } 2926 2927 if (allow_c90) 2928 check_unconst_function(lstp, rn); 2929 2930 return true; 2931 } 2932 2933 static bool 2934 check_assign_pointer_integer(op_t op, int arg, 2935 const type_t *ltp, tspec_t lt, 2936 const type_t *rtp, tspec_t rt) 2937 { 2938 2939 if (!((lt == PTR && is_integer(rt)) || (is_integer(lt) && rt == PTR))) 2940 return false; 2941 2942 const char *lx = lt == PTR ? "pointer" : "integer"; 2943 const char *rx = rt == PTR ? "pointer" : "integer"; 2944 2945 switch (op) { 2946 case INIT: 2947 case RETURN: 2948 /* illegal combination of %s '%s' and %s '%s' */ 2949 warning(183, lx, type_name(ltp), rx, type_name(rtp)); 2950 break; 2951 case FARG: 2952 /* illegal combination of %s '%s' and %s '%s', arg #%d */ 2953 warning(154, 2954 lx, type_name(ltp), rx, type_name(rtp), arg); 2955 break; 2956 default: 2957 /* illegal combination of %s '%s' and %s '%s', op '%s' */ 2958 warning(123, 2959 lx, type_name(ltp), rx, type_name(rtp), op_name(op)); 2960 break; 2961 } 2962 return true; 2963 } 2964 2965 static bool 2966 check_assign_pointer(op_t op, int arg, 2967 const type_t *ltp, tspec_t lt, 2968 const type_t *rtp, tspec_t rt) 2969 { 2970 if (!(lt == PTR && rt == PTR)) 2971 return false; 2972 2973 if (op == FARG) 2974 /* converting '%s' to incompatible '%s' for ... */ 2975 warning(153, type_name(rtp), type_name(ltp), arg); 2976 else 2977 warn_incompatible_pointers(op, ltp, rtp); 2978 return true; 2979 } 2980 2981 static void 2982 warn_assign(op_t op, int arg, 2983 const type_t *ltp, tspec_t lt, 2984 const type_t *rtp, tspec_t rt) 2985 { 2986 switch (op) { 2987 case INIT: 2988 /* cannot initialize '%s' from '%s' */ 2989 error(185, type_name(ltp), type_name(rtp)); 2990 break; 2991 case RETURN: 2992 /* function has return type '%s' but returns '%s' */ 2993 error(211, type_name(ltp), type_name(rtp)); 2994 break; 2995 case FARG: 2996 /* passing '%s' to incompatible '%s', arg #%d */ 2997 warning(155, type_name(rtp), type_name(ltp), arg); 2998 break; 2999 default: 3000 warn_incompatible_types(op, ltp, lt, rtp, rt); 3001 break; 3002 } 3003 } 3004 3005 /* 3006 * Checks type compatibility for ASSIGN, INIT, FARG and RETURN 3007 * and prints warnings/errors if necessary. 3008 * Returns whether the types are (almost) compatible. 3009 */ 3010 static bool 3011 check_assign_types_compatible(op_t op, int arg, 3012 const tnode_t *ln, const tnode_t *rn) 3013 { 3014 tspec_t lt, rt, lst = NO_TSPEC, rst = NO_TSPEC; 3015 type_t *ltp, *rtp, *lstp = NULL, *rstp = NULL; 3016 3017 if ((lt = (ltp = ln->tn_type)->t_tspec) == PTR) 3018 lst = (lstp = ltp->t_subt)->t_tspec; 3019 if ((rt = (rtp = rn->tn_type)->t_tspec) == PTR) 3020 rst = (rstp = rtp->t_subt)->t_tspec; 3021 3022 if (lt == BOOL && is_scalar(rt)) /* C99 6.3.1.2 */ 3023 return true; 3024 3025 if (is_arithmetic(lt) && (is_arithmetic(rt) || rt == BOOL)) 3026 return true; 3027 3028 if (is_struct_or_union(lt) && is_struct_or_union(rt)) 3029 return ltp->u.sou == rtp->u.sou; 3030 3031 if (lt == PTR && is_null_pointer(rn)) { 3032 if (is_integer(rn->tn_type->t_tspec)) 3033 /* implicit conversion from integer 0 to pointer ... */ 3034 query_message(15, type_name(ltp)); 3035 return true; 3036 } 3037 3038 check_assign_void_pointer(op, arg, lt, lst, rt, rst); 3039 3040 if (check_assign_void_pointer_compat(op, arg, 3041 lt, lstp, lst, rn, rtp, rt, rstp, rst)) 3042 return true; 3043 3044 if (check_assign_pointer_integer(op, arg, ltp, lt, rtp, rt)) 3045 return true; 3046 3047 if (check_assign_pointer(op, arg, ltp, lt, rtp, rt)) 3048 return true; 3049 3050 warn_assign(op, arg, ltp, lt, rtp, rt); 3051 return false; 3052 } 3053 3054 static bool 3055 has_side_effect(const tnode_t *tn) /* NOLINT(misc-no-recursion) */ 3056 { 3057 op_t op = tn->tn_op; 3058 3059 if (modtab[op].m_has_side_effect) 3060 return true; 3061 3062 if (op == CVT && tn->tn_type->t_tspec == VOID) 3063 return has_side_effect(tn->u.ops.left); 3064 3065 /* XXX: Why not has_side_effect(tn->u.ops.left) as well? */ 3066 if (op == LOGAND || op == LOGOR) 3067 return has_side_effect(tn->u.ops.right); 3068 3069 /* XXX: Why not has_side_effect(tn->u.ops.left) as well? */ 3070 if (op == QUEST) 3071 return has_side_effect(tn->u.ops.right); 3072 3073 if (op == COLON || op == COMMA) { 3074 return has_side_effect(tn->u.ops.left) || 3075 has_side_effect(tn->u.ops.right); 3076 } 3077 3078 return false; 3079 } 3080 3081 static bool 3082 is_void_cast(const tnode_t *tn) 3083 { 3084 3085 return tn->tn_op == CVT && tn->tn_cast && 3086 tn->tn_type->t_tspec == VOID; 3087 } 3088 3089 static bool 3090 is_local_symbol(const tnode_t *tn) 3091 { 3092 3093 return tn->tn_op == LOAD && 3094 tn->u.ops.left->tn_op == NAME && 3095 tn->u.ops.left->u.sym->s_scl == AUTO; 3096 } 3097 3098 static bool 3099 is_int_constant_zero(const tnode_t *tn) 3100 { 3101 3102 return tn->tn_op == CON && 3103 tn->tn_type->t_tspec == INT && 3104 tn->u.value.u.integer == 0; 3105 } 3106 3107 static void 3108 check_null_effect(const tnode_t *tn) 3109 { 3110 3111 if (hflag && 3112 !has_side_effect(tn) && 3113 !(is_void_cast(tn) && is_local_symbol(tn->u.ops.left)) && 3114 !(is_void_cast(tn) && is_int_constant_zero(tn->u.ops.left))) { 3115 /* expression has null effect */ 3116 warning(129); 3117 } 3118 } 3119 3120 /* 3121 * Check the types for specific operators and type combinations. 3122 * 3123 * At this point, the operands already conform to the type requirements of 3124 * the operator, such as being integer, floating or scalar. 3125 */ 3126 static bool 3127 typeok_op(op_t op, int arg, 3128 const tnode_t *ln, const type_t *ltp, tspec_t lt, 3129 const tnode_t *rn, const type_t *rtp, tspec_t rt) 3130 { 3131 switch (op) { 3132 case ARROW: 3133 return typeok_arrow(lt); 3134 case POINT: 3135 return typeok_point(ln, ltp, lt); 3136 case INCBEF: 3137 case DECBEF: 3138 case INCAFT: 3139 case DECAFT: 3140 return typeok_incdec(op, ln, ltp); 3141 case INDIR: 3142 return typeok_indir(ltp, lt); 3143 case ADDR: 3144 return typeok_address(op, ln, ltp, lt); 3145 case PLUS: 3146 return typeok_plus(op, ltp, lt, rtp, rt); 3147 case MINUS: 3148 return typeok_minus(op, ltp, lt, rtp, rt); 3149 case SHL: 3150 typeok_shl(op, lt, rt); 3151 goto shift; 3152 case SHR: 3153 typeok_shr(op, ln, lt, rn, rt); 3154 shift: 3155 typeok_shift(ltp, lt, rn, rt); 3156 break; 3157 case LT: 3158 case LE: 3159 case GT: 3160 case GE: 3161 compare: 3162 return typeok_compare(op, ln, ltp, lt, rn, rtp, rt); 3163 case EQ: 3164 case NE: 3165 if (is_typeok_eq(ln, lt, rn, rt)) 3166 break; 3167 goto compare; 3168 case QUEST: 3169 return typeok_quest(lt, rn); 3170 case COLON: 3171 return typeok_colon(ln, ltp, lt, rn, rtp, rt); 3172 case ASSIGN: 3173 case INIT: 3174 case FARG: 3175 case RETURN: 3176 if (!check_assign_types_compatible(op, arg, ln, rn)) 3177 return false; 3178 goto assign; 3179 case MULASS: 3180 case DIVASS: 3181 case MODASS: 3182 goto assign; 3183 case ADDASS: 3184 case SUBASS: 3185 if ((lt == PTR && !is_integer(rt)) || rt == PTR) { 3186 warn_incompatible_types(op, ltp, lt, rtp, rt); 3187 return false; 3188 } 3189 goto assign; 3190 case SHLASS: 3191 goto assign; 3192 case SHRASS: 3193 if (pflag && !is_uinteger(lt) && 3194 !(!allow_c90 && is_uinteger(rt))) { 3195 /* bitwise '%s' on signed value possibly nonportable */ 3196 warning(117, op_name(op)); 3197 } 3198 goto assign; 3199 case ANDASS: 3200 case XORASS: 3201 case ORASS: 3202 assign: 3203 return typeok_assign(op, ln, ltp, lt); 3204 case COMMA: 3205 if (!modtab[ln->tn_op].m_has_side_effect) 3206 check_null_effect(ln); 3207 break; 3208 default: 3209 break; 3210 } 3211 return true; 3212 } 3213 3214 static void 3215 check_bad_enum_operation(op_t op, const tnode_t *ln, const tnode_t *rn) 3216 { 3217 3218 if (!eflag) 3219 return; 3220 3221 /* Allow enum in array indices. */ 3222 if (op == PLUS && 3223 ((ln->tn_type->t_is_enum && rn->tn_type->t_tspec == PTR) || 3224 (rn->tn_type->t_is_enum && ln->tn_type->t_tspec == PTR))) { 3225 return; 3226 } 3227 3228 /* dubious operation '%s' on enum */ 3229 warning(241, op_name(op)); 3230 } 3231 3232 static void 3233 check_enum_type_mismatch(op_t op, int arg, const tnode_t *ln, const tnode_t *rn) 3234 { 3235 const mod_t *mp = &modtab[op]; 3236 3237 if (ln->tn_type->u.enumer != rn->tn_type->u.enumer) { 3238 switch (op) { 3239 case INIT: 3240 /* enum type mismatch between '%s' and '%s' in ... */ 3241 warning(210, 3242 type_name(ln->tn_type), type_name(rn->tn_type)); 3243 break; 3244 case FARG: 3245 /* function expects '%s', passing '%s' for arg #%d */ 3246 warning(156, 3247 type_name(ln->tn_type), type_name(rn->tn_type), 3248 arg); 3249 break; 3250 case RETURN: 3251 /* function has return type '%s' but returns '%s' */ 3252 warning(211, 3253 type_name(ln->tn_type), type_name(rn->tn_type)); 3254 break; 3255 default: 3256 /* enum type mismatch: '%s' '%s' '%s' */ 3257 warning(130, type_name(ln->tn_type), op_name(op), 3258 type_name(rn->tn_type)); 3259 break; 3260 } 3261 } else if (Pflag && eflag && mp->m_comparison && op != EQ && op != NE) 3262 /* operator '%s' assumes that '%s' is ordered */ 3263 warning(243, op_name(op), type_name(ln->tn_type)); 3264 } 3265 3266 static void 3267 check_enum_int_mismatch(op_t op, int arg, const tnode_t *ln, const tnode_t *rn) 3268 { 3269 3270 if (!eflag) 3271 return; 3272 3273 switch (op) { 3274 case INIT: 3275 /* 3276 * Initialization with 0 is allowed. Otherwise, all implicit 3277 * initializations would need to be warned upon as well. 3278 */ 3279 if (!rn->tn_type->t_is_enum && rn->tn_op == CON && 3280 is_integer(rn->tn_type->t_tspec) && 3281 rn->u.value.u.integer == 0) { 3282 return; 3283 } 3284 /* initialization of '%s' with '%s' */ 3285 warning(277, type_name(ln->tn_type), type_name(rn->tn_type)); 3286 break; 3287 case FARG: 3288 /* combination of '%s' and '%s', arg #%d */ 3289 warning(278, 3290 type_name(ln->tn_type), type_name(rn->tn_type), arg); 3291 break; 3292 case RETURN: 3293 /* combination of '%s' and '%s' in return */ 3294 warning(279, type_name(ln->tn_type), type_name(rn->tn_type)); 3295 break; 3296 default: 3297 /* combination of '%s' and '%s', op '%s' */ 3298 warning(242, type_name(ln->tn_type), type_name(rn->tn_type), 3299 op_name(op)); 3300 break; 3301 } 3302 } 3303 3304 static void 3305 typeok_enum(op_t op, const mod_t *mp, int arg, 3306 const tnode_t *ln, const type_t *ltp, 3307 const tnode_t *rn, const type_t *rtp) 3308 { 3309 if (mp->m_bad_on_enum && 3310 (ltp->t_is_enum || (mp->m_binary && rtp->t_is_enum))) { 3311 check_bad_enum_operation(op, ln, rn); 3312 } else if (mp->m_valid_on_enum && 3313 (ltp->t_is_enum && rtp != NULL && rtp->t_is_enum)) { 3314 check_enum_type_mismatch(op, arg, ln, rn); 3315 } else if (mp->m_valid_on_enum && 3316 (ltp->t_is_enum || (rtp != NULL && rtp->t_is_enum))) { 3317 check_enum_int_mismatch(op, arg, ln, rn); 3318 } 3319 } 3320 3321 /* Perform most type checks. Return whether the types are ok. */ 3322 bool 3323 typeok(op_t op, int arg, const tnode_t *ln, const tnode_t *rn) 3324 { 3325 3326 const mod_t *mp = &modtab[op]; 3327 3328 type_t *ltp = ln->tn_type; 3329 tspec_t lt = ltp->t_tspec; 3330 3331 type_t *rtp = mp->m_binary ? rn->tn_type : NULL; 3332 tspec_t rt = mp->m_binary ? rtp->t_tspec : NO_TSPEC; 3333 3334 if (Tflag && !typeok_scalar_strict_bool(op, mp, arg, ln, rn)) 3335 return false; 3336 if (!typeok_scalar(op, mp, ltp, lt, rtp, rt)) 3337 return false; 3338 3339 if (!typeok_op(op, arg, ln, ltp, lt, rn, rtp, rt)) 3340 return false; 3341 3342 typeok_enum(op, mp, arg, ln, ltp, rn, rtp); 3343 return true; 3344 } 3345 3346 /* In traditional C, keep unsigned and promote FLOAT to DOUBLE. */ 3347 static tspec_t 3348 promote_trad(tspec_t t) 3349 { 3350 3351 if (t == UCHAR || t == USHORT) 3352 return UINT; 3353 if (t == CHAR || t == SCHAR || t == SHORT) 3354 return INT; 3355 if (t == FLOAT) 3356 return DOUBLE; 3357 if (t == ENUM) 3358 return INT; 3359 return t; 3360 } 3361 3362 /* 3363 * C99 6.3.1.1p2 requires for types with lower rank than int that "If an int 3364 * can represent all the values of the original type, the value is converted 3365 * to an int; otherwise it is converted to an unsigned int", and that "All 3366 * other types are unchanged by the integer promotions". 3367 */ 3368 static tspec_t 3369 promote_c90(const tnode_t *tn, tspec_t t, bool farg) 3370 { 3371 if (tn->tn_type->t_bitfield) { 3372 unsigned int width = tn->tn_type->t_bit_field_width; 3373 unsigned int int_width = size_in_bits(INT); 3374 // XXX: What about _Bool bit-fields, since C99? 3375 if (width < int_width) 3376 return INT; 3377 if (width == int_width) 3378 return is_uinteger(t) ? UINT : INT; 3379 return t; 3380 } 3381 3382 if (t == CHAR || t == SCHAR) 3383 return INT; 3384 if (t == UCHAR) 3385 return size_in_bits(CHAR) < size_in_bits(INT) ? INT : UINT; 3386 if (t == SHORT) 3387 return INT; 3388 if (t == USHORT) 3389 return size_in_bits(SHORT) < size_in_bits(INT) ? INT : UINT; 3390 if (t == ENUM) 3391 return INT; 3392 if (farg && t == FLOAT) 3393 return DOUBLE; 3394 return t; 3395 } 3396 3397 /* 3398 * Performs the "integer promotions" (C99 6.3.1.1p2), which convert small 3399 * integer types to either int or unsigned int. 3400 * 3401 * If allow_c90 is unset or the operand is a function argument with no type 3402 * information (no prototype or variable # of args), converts float to double. 3403 */ 3404 tnode_t * 3405 promote(op_t op, bool farg, tnode_t *tn) 3406 { 3407 3408 const type_t *otp = tn->tn_type; 3409 tspec_t ot = otp->t_tspec; 3410 if (!is_arithmetic(ot)) 3411 return tn; 3412 3413 tspec_t nt = allow_c90 ? promote_c90(tn, ot, farg) : promote_trad(ot); 3414 if (nt == ot) 3415 return tn; 3416 3417 type_t *ntp = expr_dup_type(gettyp(nt)); 3418 ntp->t_tspec = nt; 3419 ntp->t_is_enum = otp->t_is_enum; 3420 if (ntp->t_is_enum) 3421 ntp->u.enumer = otp->u.enumer; 3422 ntp->t_bitfield = otp->t_bitfield; 3423 if (ntp->t_bitfield) { 3424 ntp->t_bit_field_width = otp->t_bit_field_width; 3425 ntp->t_bit_field_offset = otp->t_bit_field_offset; 3426 } 3427 if (ntp->t_bitfield && is_uinteger(ot) && !is_uinteger(nt)) 3428 ntp->t_bit_field_width++; 3429 return convert(op, 0, ntp, tn); 3430 } 3431 3432 static void 3433 check_lossy_floating_to_integer_conversion( 3434 op_t op, int arg, const type_t *tp, const tnode_t *tn) 3435 { 3436 long double x = tn->u.value.u.floating; 3437 integer_constraints ic = ic_any(tp); 3438 if (is_uinteger(tp->t_tspec) 3439 ? x >= ic.umin && x <= ic.umax && x == (uint64_t)x 3440 : x >= ic.smin && x <= ic.smax && x == (int64_t)x) 3441 return; 3442 if (op == FARG) 3443 /* lossy conversion of %Lg to '%s', arg #%d */ 3444 warning(380, x, type_name(tp), arg); 3445 else 3446 /* lossy conversion of %Lg to '%s' */ 3447 warning(381, x, type_name(tp)); 3448 } 3449 3450 static void 3451 convert_integer_from_floating( 3452 op_t op, int arg, const type_t *tp, const tnode_t *tn) 3453 { 3454 3455 if (op == CVT) 3456 /* cast from floating point '%s' to integer '%s' */ 3457 query_message(2, type_name(tn->tn_type), type_name(tp)); 3458 else 3459 /* implicit conversion from floating point '%s' to ... */ 3460 query_message(1, type_name(tn->tn_type), type_name(tp)); 3461 if (tn->tn_op == CON) 3462 check_lossy_floating_to_integer_conversion(op, arg, tp, tn); 3463 } 3464 3465 static bool 3466 should_warn_about_prototype_conversion(tspec_t nt, 3467 tspec_t ot, const tnode_t *ptn) 3468 { 3469 3470 if (nt == ot) 3471 return false; 3472 3473 if (nt == ENUM && ot == INT) 3474 return false; 3475 3476 if (is_floating(nt) != is_floating(ot) || 3477 portable_rank_cmp(nt, ot) != 0) { 3478 /* representation and/or width change */ 3479 if (!is_integer(ot)) 3480 return true; 3481 /* 3482 * XXX: Investigate whether this rule makes sense; see 3483 * tests/usr.bin/xlint/lint1/platform_long.c. 3484 */ 3485 return portable_rank_cmp(ot, INT) > 0; 3486 } 3487 3488 if (!hflag) 3489 return false; 3490 3491 /* 3492 * If the types differ only in sign and the argument has the same 3493 * representation in both types, print no warning. 3494 */ 3495 if (ptn->tn_op == CON && is_integer(nt) && 3496 signed_type(nt) == signed_type(ot) && 3497 !msb(ptn->u.value.u.integer, ot)) 3498 return false; 3499 3500 return true; 3501 } 3502 3503 /* 3504 * Warn if a prototype causes a type conversion that is different from what 3505 * would happen to the same argument in the absence of a prototype. This 3506 * check is intended for code that needs to stay compatible with pre-C90 C. 3507 * 3508 * Errors/warnings about illegal type combinations are already printed 3509 * in check_assign_types_compatible(). 3510 */ 3511 static void 3512 check_prototype_conversion(int arg, tspec_t nt, tspec_t ot, type_t *tp, 3513 tnode_t *tn) 3514 { 3515 3516 if (!is_arithmetic(nt) || !is_arithmetic(ot)) 3517 return; 3518 3519 /* 3520 * If the type of the formal parameter is char/short, a warning would 3521 * be useless, because functions declared the old style can't expect 3522 * char/short arguments. 3523 */ 3524 if (nt == CHAR || nt == SCHAR || nt == UCHAR || 3525 nt == SHORT || nt == USHORT) 3526 return; 3527 3528 tnode_t *ptn = promote(NOOP, true, tn); 3529 ot = ptn->tn_type->t_tspec; 3530 3531 if (should_warn_about_prototype_conversion(nt, ot, ptn)) { 3532 /* argument %d is converted from '%s' to '%s' ... */ 3533 warning(259, arg, type_name(tn->tn_type), type_name(tp)); 3534 } 3535 } 3536 3537 /* 3538 * When converting a large integer type to a small integer type, in some 3539 * cases the value of the actual expression is further restricted than the 3540 * type bounds, such as in (expr & 0xFF) or (expr % 100) or (expr >> 24). 3541 */ 3542 static bool 3543 can_represent(const type_t *tp, const tnode_t *tn) 3544 { 3545 uint64_t nmask = value_bits(width_in_bits(tp)); 3546 if (!is_uinteger(tp->t_tspec)) 3547 nmask >>= 1; 3548 3549 integer_constraints c = ic_expr(tn); 3550 if ((~c.bclr & ~nmask) == 0) 3551 return true; 3552 3553 integer_constraints tpc = ic_any(tp); 3554 if (is_uinteger(tp->t_tspec) 3555 ? tpc.umin <= c.umin && tpc.umax >= c.umax 3556 : tpc.smin <= c.smin && tpc.smax >= c.smax) 3557 return true; 3558 3559 debug_enter(); 3560 debug_step("type '%s' cannot represent:", type_name(tp)); 3561 debug_node(tn); 3562 debug_leave(); 3563 return false; 3564 } 3565 3566 static bool 3567 should_warn_about_integer_conversion(const type_t *ntp, tspec_t nt, 3568 const tnode_t *otn, tspec_t ot) 3569 { 3570 3571 // XXX: The portable_rank_cmp aims at portable mode, independent of the 3572 // current platform, while can_represent acts on the actual type sizes 3573 // from the current platform. This mix is inconsistent, but anything 3574 // else would make the exact conditions too complicated to grasp. 3575 if (aflag > 0 && portable_rank_cmp(nt, ot) < 0) { 3576 if (ot == LONG || ot == ULONG 3577 || ot == LLONG || ot == ULLONG 3578 #ifdef INT128_SIZE 3579 || ot == INT128 || ot == UINT128 3580 #endif 3581 || aflag > 1) 3582 return !can_represent(ntp, otn); 3583 } 3584 return false; 3585 } 3586 3587 static void 3588 convert_integer_from_integer(op_t op, int arg, tspec_t nt, tspec_t ot, 3589 type_t *tp, tnode_t *tn) 3590 { 3591 3592 if (tn->tn_op == CON) 3593 return; 3594 3595 if (op == CVT) 3596 return; 3597 3598 if (Pflag && pflag && aflag > 0 && 3599 portable_rank_cmp(nt, ot) > 0 && 3600 is_uinteger(nt) != is_uinteger(ot)) { 3601 if (op == FARG) 3602 /* conversion to '%s' may sign-extend ... */ 3603 warning(297, type_name(tp), arg); 3604 else 3605 /* conversion to '%s' may sign-extend ... */ 3606 warning(131, type_name(tp)); 3607 } 3608 3609 if (Pflag && portable_rank_cmp(nt, ot) > 0 && 3610 (tn->tn_op == PLUS || tn->tn_op == MINUS || tn->tn_op == MULT || 3611 tn->tn_op == SHL)) { 3612 /* suggest cast from '%s' to '%s' on op '%s' to ... */ 3613 warning(324, type_name(gettyp(ot)), type_name(tp), 3614 op_name(tn->tn_op)); 3615 } 3616 3617 if (should_warn_about_integer_conversion(tp, nt, tn, ot)) { 3618 if (op == FARG) { 3619 /* conversion from '%s' to '%s' may lose ... */ 3620 warning(298, 3621 type_name(tn->tn_type), type_name(tp), arg); 3622 } else { 3623 /* conversion from '%s' to '%s' may lose accuracy */ 3624 warning(132, 3625 type_name(tn->tn_type), type_name(tp)); 3626 } 3627 } 3628 3629 if (is_uinteger(nt) != is_uinteger(ot)) 3630 /* implicit conversion changes sign from '%s' to '%s' */ 3631 query_message(3, type_name(tn->tn_type), type_name(tp)); 3632 } 3633 3634 static void 3635 convert_integer_from_pointer(op_t op, tspec_t nt, type_t *tp, tnode_t *tn) 3636 { 3637 3638 if (tn->tn_op == CON) 3639 return; 3640 if (op != CVT) 3641 return; /* We already got an error. */ 3642 if (portable_rank_cmp(nt, PTR) >= 0) 3643 return; 3644 3645 if (pflag && size_in_bits(nt) >= size_in_bits(PTR)) { 3646 /* conversion of pointer to '%s' may lose bits */ 3647 warning(134, type_name(tp)); 3648 } else { 3649 /* conversion of pointer to '%s' loses bits */ 3650 warning(133, type_name(tp)); 3651 } 3652 } 3653 3654 static bool 3655 struct_starts_with(const type_t *struct_tp, const type_t *member_tp) 3656 { 3657 3658 return struct_tp->u.sou->sou_first_member != NULL && 3659 types_compatible(struct_tp->u.sou->sou_first_member->s_type, 3660 member_tp, true, false, NULL); 3661 } 3662 3663 static bool 3664 is_byte_array(const type_t *tp) 3665 { 3666 3667 return tp->t_tspec == ARRAY && 3668 (tp->t_subt->t_tspec == CHAR || tp->t_subt->t_tspec == UCHAR); 3669 } 3670 3671 static bool 3672 union_contains(const type_t *utp, const type_t *mtp) 3673 { 3674 for (const sym_t *mem = utp->u.sou->sou_first_member; 3675 mem != NULL; mem = mem->s_next) { 3676 if (types_compatible(mem->s_type, mtp, true, false, NULL)) 3677 return true; 3678 } 3679 return false; 3680 } 3681 3682 static bool 3683 should_warn_about_pointer_cast(const type_t *nstp, tspec_t nst, 3684 const type_t *ostp, tspec_t ost) 3685 { 3686 3687 while (nst == ARRAY) 3688 nstp = nstp->t_subt, nst = nstp->t_tspec; 3689 while (ost == ARRAY) 3690 ostp = ostp->t_subt, ost = ostp->t_tspec; 3691 3692 if (nst == STRUCT && ost == STRUCT && 3693 (struct_starts_with(nstp, ostp) || 3694 struct_starts_with(ostp, nstp))) 3695 return false; 3696 3697 if (is_incomplete(nstp) || is_incomplete(ostp)) 3698 return false; 3699 3700 if (nst == CHAR || nst == UCHAR) 3701 return false; /* for the sake of traditional C code */ 3702 if (ost == CHAR || ost == UCHAR) 3703 return false; /* for the sake of traditional C code */ 3704 3705 /* Allow cast between pointers to sockaddr variants. */ 3706 if (nst == STRUCT && ost == STRUCT) { 3707 const sym_t *nmem = nstp->u.sou->sou_first_member; 3708 const sym_t *omem = ostp->u.sou->sou_first_member; 3709 while (nmem != NULL && omem != NULL && 3710 types_compatible(nmem->s_type, omem->s_type, 3711 true, false, NULL)) 3712 nmem = nmem->s_next, omem = omem->s_next; 3713 if (nmem != NULL && is_byte_array(nmem->s_type)) 3714 return false; 3715 if (omem != NULL && is_byte_array(omem->s_type)) 3716 return false; 3717 if (nmem == NULL && omem == NULL) 3718 return false; 3719 } 3720 3721 if (nst == UNION || ost == UNION) { 3722 const type_t *union_tp = nst == UNION ? nstp : ostp; 3723 const type_t *other_tp = nst == UNION ? ostp : nstp; 3724 if (union_contains(union_tp, other_tp)) 3725 return false; 3726 } 3727 3728 if (is_struct_or_union(nst) && is_struct_or_union(ost)) 3729 return nstp->u.sou != ostp->u.sou; 3730 3731 enum rank_kind rk1 = type_properties(nst)->tt_rank_kind; 3732 enum rank_kind rk2 = type_properties(ost)->tt_rank_kind; 3733 if (rk1 != rk2 || rk1 == RK_NONE) 3734 return true; 3735 3736 return portable_rank_cmp(nst, ost) != 0; 3737 } 3738 3739 static void 3740 convert_pointer_from_pointer(type_t *ntp, tnode_t *tn) 3741 { 3742 const type_t *nstp = ntp->t_subt; 3743 const type_t *otp = tn->tn_type; 3744 const type_t *ostp = otp->t_subt; 3745 tspec_t nst = nstp->t_tspec; 3746 tspec_t ost = ostp->t_tspec; 3747 3748 if (nst == VOID || ost == VOID) { 3749 /* TODO: C99 behaves like C90 here. */ 3750 if (!allow_trad && !allow_c99 && (nst == FUNC || ost == FUNC)) { 3751 const char *nts, *ots; 3752 /* null pointers are already handled in convert() */ 3753 *(nst == FUNC ? &nts : &ots) = "function pointer"; 3754 *(nst == VOID ? &nts : &ots) = "'void *'"; 3755 /* conversion of %s to %s requires a cast */ 3756 warning(303, ots, nts); 3757 } 3758 return; 3759 } 3760 if (nst == FUNC && ost == FUNC) 3761 return; 3762 if (nst == FUNC || ost == FUNC) { 3763 /* converting '%s' to '%s' is questionable */ 3764 warning(229, type_name(otp), type_name(ntp)); 3765 return; 3766 } 3767 3768 if (hflag && alignment(nstp) > alignment(ostp) && 3769 ost != CHAR && ost != UCHAR && 3770 !is_incomplete(ostp) && 3771 !(nst == UNION && union_contains(nstp, ostp))) { 3772 /* converting '%s' to '%s' increases alignment ... */ 3773 warning(135, type_name(otp), type_name(ntp), 3774 alignment(ostp), alignment(nstp)); 3775 } 3776 3777 if (cflag && should_warn_about_pointer_cast(nstp, nst, ostp, ost)) { 3778 /* pointer cast from '%s' to unrelated '%s' */ 3779 warning(247, type_name(ostp), type_name(nstp)); 3780 } 3781 } 3782 3783 /* 3784 * Insert a conversion operator, which converts the type of the node 3785 * to another given type. 3786 * 3787 * Possible values for 'op': 3788 * CVT a cast-expression 3789 * binary integer promotion for one of the operands, or a usual 3790 * arithmetic conversion 3791 * binary plain or compound assignments to bit-fields 3792 * FARG 'arg' is the number of the parameter (used for warnings) 3793 * NOOP several other implicit conversions 3794 * ... 3795 */ 3796 tnode_t * 3797 convert(op_t op, int arg, type_t *tp, tnode_t *tn) 3798 { 3799 tspec_t nt = tp->t_tspec; 3800 tspec_t ot = tn->tn_type->t_tspec; 3801 3802 if (allow_trad && allow_c90 && op == FARG) 3803 check_prototype_conversion(arg, nt, ot, tp, tn); 3804 3805 if (nt == BOOL) { 3806 /* No further checks. */ 3807 3808 } else if (is_integer(nt)) { 3809 if (ot == BOOL) { 3810 /* No further checks. */ 3811 } else if (is_integer(ot)) 3812 convert_integer_from_integer(op, arg, nt, ot, tp, tn); 3813 else if (is_floating(ot)) 3814 convert_integer_from_floating(op, arg, tp, tn); 3815 else if (ot == PTR) 3816 convert_integer_from_pointer(op, nt, tp, tn); 3817 3818 } else if (is_floating(nt)) { 3819 if (is_integer(ot) && op != CVT) { 3820 /* implicit conversion from integer '%s' to ... */ 3821 query_message(19, 3822 type_name(tn->tn_type), type_name(tp)); 3823 } 3824 3825 } else if (nt == PTR) { 3826 if (is_null_pointer(tn)) { 3827 /* a null pointer may be assigned to any pointer. */ 3828 } else if (ot == PTR && op == CVT) 3829 convert_pointer_from_pointer(tp, tn); 3830 } 3831 3832 tnode_t *ntn = expr_alloc_tnode(); 3833 ntn->tn_op = CVT; 3834 ntn->tn_type = tp; 3835 ntn->tn_cast = op == CVT; 3836 ntn->tn_sys |= tn->tn_sys; 3837 ntn->u.ops.right = NULL; 3838 if (tn->tn_op != CON || nt == VOID) { 3839 ntn->u.ops.left = tn; 3840 } else { 3841 ntn->tn_op = CON; 3842 convert_constant(op, arg, ntn->tn_type, &ntn->u.value, 3843 &tn->u.value); 3844 } 3845 3846 return ntn; 3847 } 3848 3849 static void 3850 convert_constant_from_floating(op_t op, int arg, const type_t *ntp, 3851 tspec_t nt, val_t *nv, val_t *ov) 3852 { 3853 long double max = 0.0, min = 0.0; 3854 3855 switch (nt) { 3856 case CHAR: 3857 max = TARG_CHAR_MAX; min = TARG_CHAR_MIN; break; 3858 case UCHAR: 3859 max = TARG_UCHAR_MAX; min = 0; break; 3860 case SCHAR: 3861 max = TARG_SCHAR_MAX; min = TARG_SCHAR_MIN; break; 3862 case SHORT: 3863 max = TARG_SHRT_MAX; min = TARG_SHRT_MIN; break; 3864 case USHORT: 3865 max = TARG_USHRT_MAX; min = 0; break; 3866 case ENUM: 3867 case INT: 3868 max = TARG_INT_MAX; min = TARG_INT_MIN; break; 3869 case UINT: 3870 max = TARG_UINT_MAX; min = 0; break; 3871 case LONG: 3872 max = TARG_LONG_MAX; min = TARG_LONG_MIN; break; 3873 case ULONG: 3874 max = TARG_ULONG_MAX; min = 0; break; 3875 case LLONG: 3876 max = LLONG_MAX; min = LLONG_MIN; break; 3877 case ULLONG: 3878 max = ULLONG_MAX; min = 0; break; 3879 case FLOAT: 3880 case FCOMPLEX: 3881 max = FLT_MAX; min = -FLT_MAX; break; 3882 case DOUBLE: 3883 case DCOMPLEX: 3884 max = DBL_MAX; min = -DBL_MAX; break; 3885 case LDOUBLE: 3886 case LCOMPLEX: 3887 /* LINTED 248; see floating_error_value. */ 3888 max = LDBL_MAX; min = -max; break; 3889 default: 3890 lint_assert(/*CONSTCOND*/false); 3891 } 3892 if (ov->u.floating > max || ov->u.floating < min) { 3893 lint_assert(nt != LDOUBLE); 3894 const char *ot_name = type_name(gettyp(ov->v_tspec)); 3895 const char *nt_name = type_name(ntp); 3896 if (is_integer(nt)) 3897 goto after_warning; 3898 if (op == FARG) 3899 /* conversion of '%s' to '%s' is out of range, ... */ 3900 warning(295, ot_name, nt_name, arg); 3901 else 3902 /* conversion of '%s' to '%s' is out of range */ 3903 warning(119, ot_name, nt_name); 3904 after_warning: 3905 ov->u.floating = ov->u.floating > 0 ? max : min; 3906 } 3907 3908 if (nt == FLOAT || nt == FCOMPLEX) 3909 nv->u.floating = (float)ov->u.floating; 3910 else if (nt == DOUBLE || nt == DCOMPLEX) 3911 nv->u.floating = (double)ov->u.floating; 3912 else if (nt == LDOUBLE || nt == LCOMPLEX) 3913 nv->u.floating = ov->u.floating; 3914 else 3915 nv->u.integer = (int64_t)ov->u.floating; 3916 } 3917 3918 static bool 3919 convert_constant_to_floating(tspec_t nt, val_t *nv, 3920 tspec_t ot, const val_t *v) 3921 { 3922 if (nt == FLOAT) { 3923 nv->u.floating = (ot == PTR || is_uinteger(ot)) ? 3924 (float)(uint64_t)v->u.integer : (float)v->u.integer; 3925 } else if (nt == DOUBLE) { 3926 nv->u.floating = (ot == PTR || is_uinteger(ot)) ? 3927 (double)(uint64_t)v->u.integer : (double)v->u.integer; 3928 } else if (nt == LDOUBLE) { 3929 nv->u.floating = (ot == PTR || is_uinteger(ot)) 3930 ? (long double)(uint64_t)v->u.integer 3931 : (long double)v->u.integer; 3932 } else 3933 return false; 3934 return true; 3935 } 3936 3937 /* 3938 * Print a warning if bits which were set are lost due to the conversion. 3939 * This can happen with operator ORASS only. 3940 */ 3941 static void 3942 convert_constant_check_range_bitor(size_t nsz, size_t osz, const val_t *v, 3943 uint64_t xmask, op_t op) 3944 { 3945 if (nsz < osz && (v->u.integer & xmask) != 0) 3946 /* constant truncated by conversion, op '%s' */ 3947 warning(306, op_name(op)); 3948 } 3949 3950 static void 3951 convert_constant_check_range_bitand(size_t nsz, size_t osz, 3952 uint64_t xmask, const val_t *nv, 3953 tspec_t ot, const val_t *v, 3954 const type_t *tp, op_t op) 3955 { 3956 if (nsz > osz && 3957 (nv->u.integer & bit((unsigned int)(osz - 1))) != 0 && 3958 (nv->u.integer & xmask) != xmask) { 3959 /* extra bits set to 0 in conversion of '%s' to '%s', ... */ 3960 warning(309, type_name(gettyp(ot)), 3961 type_name(tp), op_name(op)); 3962 } else if (nsz < osz && 3963 (v->u.integer & xmask) != xmask && 3964 (v->u.integer & xmask) != 0) 3965 /* constant truncated by conversion, op '%s' */ 3966 warning(306, op_name(op)); 3967 } 3968 3969 static void 3970 convert_constant_check_range_signed(op_t op, int arg, 3971 const type_t *ntp, int64_t ov) 3972 { 3973 if (op == ASSIGN) 3974 /* assignment of negative constant %lld to unsigned ... */ 3975 warning(164, (long long)ov, type_name(ntp)); 3976 else if (op == INIT) 3977 /* initialization of unsigned type '%s' with negative ... */ 3978 warning(221, type_name(ntp), (long long)ov); 3979 else if (op == FARG) 3980 /* conversion of negative constant %lld to unsigned ... */ 3981 warning(296, (long long)ov, type_name(ntp), arg); 3982 else if (modtab[op].m_comparison) { 3983 /* handled by check_integer_comparison() */ 3984 } else 3985 /* conversion of negative constant %lld to unsigned ... */ 3986 warning(222, (long long)ov, type_name(ntp)); 3987 } 3988 3989 /* 3990 * Loss of significant bit(s). All truncated bits of unsigned types or all 3991 * truncated bits plus the msb of the target for signed types are considered 3992 * to be significant bits. Loss of significant bits means that at least one 3993 * of the bits was set in an unsigned type or that at least one but not all 3994 * of the bits was set in a signed type. Loss of significant bits means that 3995 * it is not possible, also not with necessary casts, to convert back to the 3996 * original type. An example for a necessary cast is: 3997 * char c; int i; c = 128; 3998 * i = c; ** yields -128 ** 3999 * i = (unsigned char)c; ** yields 128 ** 4000 */ 4001 static void 4002 warn_constant_check_range_truncated(op_t op, int arg, const type_t *tp, 4003 tspec_t ot) 4004 { 4005 if (op == ASSIGN && tp->t_bitfield) 4006 /* precision lost in bit-field assignment */ 4007 warning(166); 4008 else if (op == ASSIGN) 4009 /* constant truncated by assignment */ 4010 warning(165); 4011 else if (op == INIT && tp->t_bitfield) 4012 /* bit-field initializer does not fit */ 4013 warning(180); 4014 else if (op == INIT) 4015 /* initializer does not fit */ 4016 warning(178); 4017 else if (op == CASE) 4018 /* case label affected by conversion */ 4019 warning(196); 4020 else if (op == FARG) 4021 /* conversion of '%s' to '%s' is out of range, arg #%d */ 4022 warning(295, type_name(gettyp(ot)), type_name(tp), arg); 4023 else 4024 /* conversion of '%s' to '%s' is out of range */ 4025 warning(119, type_name(gettyp(ot)), type_name(tp)); 4026 } 4027 4028 static void 4029 warn_constant_check_range_loss(op_t op, int arg, const type_t *tp, 4030 tspec_t ot) 4031 { 4032 if (op == ASSIGN && tp->t_bitfield) 4033 /* precision lost in bit-field assignment */ 4034 warning(166); 4035 else if (op == INIT && tp->t_bitfield) 4036 /* bit-field initializer out of range */ 4037 warning(11); 4038 else if (op == CASE) 4039 /* case label affected by conversion */ 4040 warning(196); 4041 else if (op == FARG) 4042 /* conversion of '%s' to '%s' is out of range, arg #%d */ 4043 warning(295, type_name(gettyp(ot)), type_name(tp), arg); 4044 else 4045 /* conversion of '%s' to '%s' is out of range */ 4046 warning(119, type_name(gettyp(ot)), type_name(tp)); 4047 } 4048 4049 static void 4050 convert_constant_check_range(tspec_t ot, const type_t *tp, tspec_t nt, 4051 op_t op, int arg, const val_t *v, val_t *nv) 4052 { 4053 unsigned int obitsz, nbitsz; 4054 uint64_t xmask, xmsk1; 4055 4056 obitsz = size_in_bits(ot); 4057 nbitsz = tp->t_bitfield ? tp->t_bit_field_width : size_in_bits(nt); 4058 xmask = value_bits(nbitsz) ^ value_bits(obitsz); 4059 xmsk1 = value_bits(nbitsz) ^ value_bits(obitsz - 1); 4060 if (op == ORASS || op == BITOR || op == BITXOR) { 4061 convert_constant_check_range_bitor( 4062 nbitsz, obitsz, v, xmask, op); 4063 } else if (op == ANDASS || op == BITAND) { 4064 convert_constant_check_range_bitand( 4065 nbitsz, obitsz, xmask, nv, ot, v, tp, op); 4066 } else if (nt != PTR && is_uinteger(nt) && 4067 ot != PTR && !is_uinteger(ot) && 4068 v->u.integer < 0) 4069 convert_constant_check_range_signed(op, arg, 4070 tp, v->u.integer); 4071 else if (nv->u.integer != v->u.integer && nbitsz <= obitsz && 4072 (v->u.integer & xmask) != 0 && 4073 (is_uinteger(ot) || (v->u.integer & xmsk1) != xmsk1)) 4074 warn_constant_check_range_truncated(op, arg, tp, ot); 4075 else if (nv->u.integer != v->u.integer) 4076 warn_constant_check_range_loss(op, arg, tp, ot); 4077 } 4078 4079 /* Converts a typed constant to a constant of another type. */ 4080 void 4081 convert_constant(op_t op, int arg, const type_t *ntp, val_t *nv, val_t *ov) 4082 { 4083 /* 4084 * TODO: make 'ov' const; the name of this function does not suggest 4085 * that it modifies 'ov'. 4086 */ 4087 tspec_t ot = ov->v_tspec; 4088 tspec_t nt = nv->v_tspec = ntp->t_tspec; 4089 bool range_check = false; 4090 4091 if (nt == BOOL) { /* C99 6.3.1.2 */ 4092 nv->v_unsigned_since_c90 = false; 4093 nv->u.integer = is_nonzero_val(ov) ? 1 : 0; 4094 return; 4095 } 4096 4097 if (ot == FLOAT || ot == DOUBLE || ot == LDOUBLE) 4098 convert_constant_from_floating(op, arg, ntp, nt, nv, ov); 4099 else if (!convert_constant_to_floating(nt, nv, ot, ov)) { 4100 range_check = true; /* Check for lost precision. */ 4101 nv->u.integer = ov->u.integer; 4102 } 4103 4104 if (allow_trad && allow_c90 && ov->v_unsigned_since_c90 && 4105 (is_floating(nt) || ( 4106 (is_integer(nt) && !is_uinteger(nt) && 4107 portable_rank_cmp(nt, ot) > 0)))) { 4108 /* C90 treats constant as unsigned */ 4109 warning(157); 4110 ov->v_unsigned_since_c90 = false; 4111 } 4112 4113 if (is_integer(nt)) { 4114 unsigned int size = ntp->t_bitfield 4115 ? ntp->t_bit_field_width : size_in_bits(nt); 4116 nv->u.integer = convert_integer(nv->u.integer, nt, size); 4117 } 4118 4119 if (range_check && op != CVT) 4120 convert_constant_check_range(ot, ntp, nt, op, arg, ov, nv); 4121 } 4122 4123 tnode_t * 4124 build_sizeof(const type_t *tp) 4125 { 4126 unsigned int size_in_bytes = type_size_in_bits(tp) / CHAR_SIZE; 4127 tnode_t *tn = build_integer_constant(SIZEOF_TSPEC, size_in_bytes); 4128 tn->tn_system_dependent = true; 4129 debug_step("build_sizeof '%s' = %u", type_name(tp), size_in_bytes); 4130 return tn; 4131 } 4132 4133 tnode_t * 4134 build_offsetof(const type_t *tp, designation dn) 4135 { 4136 unsigned int offset_in_bits = 0; 4137 4138 if (!is_struct_or_union(tp->t_tspec)) { 4139 /* unacceptable operand of '%s' */ 4140 error(111, "offsetof"); 4141 goto proceed; 4142 } 4143 for (size_t i = 0; i < dn.dn_len; i++) { 4144 const designator *dr = dn.dn_items + i; 4145 if (dr->dr_kind == DK_SUBSCRIPT) { 4146 if (tp->t_tspec != ARRAY) 4147 goto proceed; /* silent error */ 4148 tp = tp->t_subt; 4149 offset_in_bits += (unsigned) dr->dr_subscript 4150 * type_size_in_bits(tp); 4151 } else { 4152 if (!is_struct_or_union(tp->t_tspec)) 4153 goto proceed; /* silent error */ 4154 const char *name = dr->dr_member->s_name; 4155 sym_t *mem = find_member(tp->u.sou, name); 4156 if (mem == NULL) { 4157 /* type '%s' does not have member '%s' */ 4158 error(101, name, type_name(tp)); 4159 goto proceed; 4160 } 4161 tp = mem->s_type; 4162 offset_in_bits += mem->u.s_member.sm_offset_in_bits; 4163 } 4164 } 4165 free(dn.dn_items); 4166 4167 proceed:; 4168 unsigned int offset_in_bytes = offset_in_bits / CHAR_SIZE; 4169 tnode_t *tn = build_integer_constant(SIZEOF_TSPEC, offset_in_bytes); 4170 tn->tn_system_dependent = true; 4171 return tn; 4172 } 4173 4174 unsigned int 4175 type_size_in_bits(const type_t *tp) 4176 { 4177 4178 unsigned int elem = 1; 4179 bool flex = false; 4180 lint_assert(tp != NULL); 4181 while (tp->t_tspec == ARRAY) { 4182 flex = true; /* allow c99 flex arrays [] [0] */ 4183 elem *= tp->u.dimension; 4184 tp = tp->t_subt; 4185 } 4186 if (elem == 0 && !flex) { 4187 /* cannot take size/alignment of incomplete type */ 4188 error(143); 4189 elem = 1; 4190 } 4191 4192 unsigned int elsz; 4193 switch (tp->t_tspec) { 4194 case VOID: 4195 /* cannot take size/alignment of void */ 4196 error(146); 4197 elsz = 1; 4198 break; 4199 case FUNC: 4200 /* cannot take size/alignment of function type '%s' */ 4201 error(144, type_name(tp)); 4202 elsz = 1; 4203 break; 4204 case STRUCT: 4205 case UNION: 4206 if (is_incomplete(tp)) { 4207 /* cannot take size/alignment of incomplete type */ 4208 error(143); 4209 elsz = 1; 4210 } else 4211 elsz = tp->u.sou->sou_size_in_bits; 4212 break; 4213 case ENUM: 4214 if (is_incomplete(tp)) { 4215 /* cannot take size/alignment of incomplete type */ 4216 warning(143); 4217 } 4218 /* FALLTHROUGH */ 4219 default: 4220 if (tp->t_bitfield) 4221 /* cannot take size/alignment of bit-field */ 4222 error(145); 4223 elsz = size_in_bits(tp->t_tspec); 4224 lint_assert(elsz > 0); 4225 break; 4226 } 4227 4228 return elem * elsz; 4229 } 4230 4231 /* C11 6.5.3.4, GCC */ 4232 tnode_t * 4233 build_alignof(const type_t *tp) 4234 { 4235 if (tp->t_tspec == FUNC) { 4236 /* cannot take size/alignment of function type '%s' */ 4237 error(144, type_name(tp)); 4238 return NULL; 4239 } 4240 if (tp->t_tspec == VOID) { 4241 /* cannot take size/alignment of void */ 4242 error(146); 4243 return NULL; 4244 } 4245 if (is_incomplete(tp)) { 4246 /* cannot take size/alignment of incomplete type */ 4247 error(143); 4248 return NULL; 4249 } 4250 if (tp->t_bitfield) { 4251 /* cannot take size/alignment of bit-field */ 4252 error(145); 4253 return NULL; 4254 } 4255 return build_integer_constant(SIZEOF_TSPEC, (int64_t)alignment(tp)); 4256 } 4257 4258 static tnode_t * 4259 cast_to_union(tnode_t *otn, bool sys, type_t *ntp) 4260 { 4261 4262 if (!allow_gcc) { 4263 /* union cast is a GCC extension */ 4264 error(328); 4265 return NULL; 4266 } 4267 4268 for (const sym_t *m = ntp->u.sou->sou_first_member; 4269 m != NULL; m = m->s_next) { 4270 if (types_compatible(m->s_type, otn->tn_type, 4271 false, false, NULL)) { 4272 tnode_t *ntn = build_op(CVT, sys, ntp, otn, NULL); 4273 ntn->tn_cast = true; 4274 return ntn; 4275 } 4276 } 4277 4278 /* type '%s' is not a member of '%s' */ 4279 error(329, type_name(otn->tn_type), type_name(ntp)); 4280 return NULL; 4281 } 4282 4283 // In GCC mode, allow 'nullptr + offset' as a constant expression. 4284 static tnode_t * 4285 null_pointer_offset(tnode_t *tn) 4286 { 4287 uint64_t off = 0; 4288 const tnode_t *n = tn; 4289 while ((n->tn_op == PLUS || n->tn_op == MINUS) 4290 && is_integer(n->u.ops.right->tn_type->t_tspec)) { 4291 off += (uint64_t)n->u.ops.right->u.value.u.integer; 4292 n = n->u.ops.left; 4293 } 4294 if (n->tn_type->t_tspec == PTR 4295 && n->tn_op == ADDR 4296 && n->u.ops.left->tn_op == INDIR 4297 && n->u.ops.left->u.ops.left->tn_op == CON 4298 && n->u.ops.left->u.ops.left->tn_type->t_tspec == PTR) { 4299 off += (uint64_t)n->u.ops.left->u.ops.left->u.value.u.integer; 4300 return build_integer_constant(SIZEOF_TSPEC, (int64_t)off); 4301 } 4302 return tn; 4303 } 4304 4305 tnode_t * 4306 cast(tnode_t *tn, bool sys, type_t *tp) 4307 { 4308 4309 if (tn == NULL) 4310 return NULL; 4311 4312 tn = cconv(tn); 4313 4314 lint_assert(tp != NULL); 4315 tspec_t nt = tp->t_tspec; 4316 tspec_t ot = tn->tn_type->t_tspec; 4317 4318 if (nt == VOID) { 4319 /* 4320 * C90 6.3.4, C99 6.5.4p2 and C11 6.5.4p2 allow any type to be 4321 * cast to void. The only other allowed casts are from a 4322 * scalar type to a scalar type. 4323 */ 4324 } else if (nt == UNION) 4325 return cast_to_union(tn, sys, tp); 4326 else if (nt == STRUCT || nt == ARRAY || nt == FUNC) { 4327 /* Casting to a struct is an undocumented GCC extension. */ 4328 if (!(allow_gcc && nt == STRUCT)) 4329 goto invalid_cast; 4330 } else if (is_struct_or_union(ot)) 4331 goto invalid_cast; 4332 else if (ot == VOID) { 4333 /* improper cast of void expression */ 4334 error(148); 4335 return NULL; 4336 } else if (is_integer(nt) && is_scalar(ot)) { 4337 tn = null_pointer_offset(tn); 4338 } else if (is_floating(nt) && is_arithmetic(ot)) { 4339 /* ok */ 4340 } else if (nt == PTR && is_integer(ot)) { 4341 /* ok */ 4342 } else if (nt == PTR && ot == PTR) { 4343 if (!tp->t_subt->t_const && tn->tn_type->t_subt->t_const) { 4344 if (hflag) 4345 /* cast discards 'const' from type '%s' */ 4346 warning(275, type_name(tn->tn_type)); 4347 } 4348 } else 4349 goto invalid_cast; 4350 4351 if (any_query_enabled 4352 && types_compatible(tp, tn->tn_type, false, false, NULL)) 4353 /* no-op cast from '%s' to '%s' */ 4354 query_message(6, type_name(tn->tn_type), type_name(tp)); 4355 4356 tn = convert(CVT, 0, tp, tn); 4357 tn->tn_cast = true; 4358 tn->tn_sys = sys; 4359 4360 return tn; 4361 4362 invalid_cast: 4363 /* invalid cast from '%s' to '%s' */ 4364 error(147, type_name(tn->tn_type), type_name(tp)); 4365 return NULL; 4366 } 4367 4368 void 4369 add_function_argument(function_call *call, tnode_t *arg) 4370 { 4371 /* 4372 * If there was a serious error in the expression for the argument, 4373 * create a dummy argument so the positions of the remaining arguments 4374 * will not change. 4375 */ 4376 if (arg == NULL) 4377 arg = build_integer_constant(INT, 0); 4378 4379 if (call->args_len >= call->args_cap) { 4380 call->args_cap += 8; 4381 tnode_t **new_args = expr_zero_alloc( 4382 call->args_cap * sizeof(*call->args), "tnode*[]"); 4383 if (call->args_len > 0) 4384 memcpy(new_args, call->args, 4385 call->args_len * sizeof(*call->args)); 4386 call->args = new_args; 4387 } 4388 call->args[call->args_len++] = arg; 4389 } 4390 4391 /* 4392 * Compare the type of an argument with the corresponding type of a 4393 * prototype parameter. If it is a valid combination, but both types 4394 * are not the same, insert a conversion to convert the argument into 4395 * the type of the parameter. 4396 */ 4397 static tnode_t * 4398 check_prototype_argument( 4399 int n, /* pos of arg */ 4400 type_t *tp, /* expected type (from prototype) */ 4401 tnode_t *tn) /* argument */ 4402 { 4403 tnode_t *ln = xcalloc(1, sizeof(*ln)); 4404 ln->tn_type = expr_unqualified_type(tp); 4405 ln->tn_lvalue = true; 4406 if (typeok(FARG, n, ln, tn)) { 4407 bool dowarn; 4408 if (!types_compatible(tp, tn->tn_type, 4409 true, false, (dowarn = false, &dowarn)) || dowarn) 4410 tn = convert(FARG, n, tp, tn); 4411 } 4412 free(ln); 4413 return tn; 4414 } 4415 4416 /* 4417 * Check types of all function arguments and insert conversions, 4418 * if necessary. 4419 */ 4420 static void 4421 check_function_arguments(const function_call *call) 4422 { 4423 type_t *ftp = call->func->tn_type->t_subt; 4424 4425 /* get # of parameters in the prototype */ 4426 int npar = 0; 4427 for (const sym_t *p = ftp->u.params; p != NULL; p = p->s_next) 4428 npar++; 4429 4430 int narg = (int)call->args_len; 4431 4432 const sym_t *param = ftp->u.params; 4433 if (ftp->t_proto && npar != narg && !(ftp->t_vararg && npar < narg)) { 4434 /* argument mismatch: %d %s passed, %d expected */ 4435 error(150, narg, narg != 1 ? "arguments" : "argument", npar); 4436 param = NULL; 4437 } 4438 4439 for (int i = 0; i < narg; i++) { 4440 tnode_t *arg = call->args[i]; 4441 4442 /* some things which are always not allowed */ 4443 tspec_t at = arg->tn_type->t_tspec; 4444 if (at == VOID) { 4445 /* void expressions may not be arguments, arg #%d */ 4446 error(151, i + 1); 4447 return; 4448 } 4449 if (is_struct_or_union(at) && is_incomplete(arg->tn_type)) { 4450 /* argument cannot have unknown size, arg #%d */ 4451 error(152, i + 1); 4452 return; 4453 } 4454 if (is_integer(at) && 4455 arg->tn_type->t_is_enum && 4456 is_incomplete(arg->tn_type)) { 4457 /* argument cannot have unknown size, arg #%d */ 4458 warning(152, i + 1); 4459 } 4460 4461 arg = cconv(arg); 4462 call->args[i] = arg; 4463 4464 arg = param != NULL 4465 ? check_prototype_argument(i + 1, param->s_type, arg) 4466 : promote(NOOP, true, arg); 4467 call->args[i] = arg; 4468 4469 if (param != NULL) 4470 param = param->s_next; 4471 } 4472 } 4473 4474 tnode_t * 4475 build_function_call(tnode_t *func, bool sys, function_call *call) 4476 { 4477 4478 if (func == NULL) 4479 return NULL; 4480 4481 call->func = func; 4482 check_ctype_function_call(call); 4483 4484 func = cconv(func); 4485 call->func = func; 4486 4487 if (func->tn_type->t_tspec != PTR || 4488 func->tn_type->t_subt->t_tspec != FUNC) { 4489 /* cannot call '%s', must be a function */ 4490 error(149, type_name(func->tn_type)); 4491 return NULL; 4492 } 4493 4494 check_function_arguments(call); 4495 4496 tnode_t *ntn = expr_alloc_tnode(); 4497 ntn->tn_op = CALL; 4498 ntn->tn_type = func->tn_type->t_subt->t_subt; 4499 ntn->tn_sys = sys; 4500 ntn->u.call = call; 4501 return ntn; 4502 } 4503 4504 /* 4505 * Return the value of an integral constant expression. 4506 * If the expression is not constant or its type is not an integer 4507 * type, an error message is printed. 4508 */ 4509 val_t * 4510 integer_constant(tnode_t *tn, bool required) 4511 { 4512 4513 if (tn != NULL) 4514 tn = cconv(tn); 4515 if (tn != NULL) 4516 tn = promote(NOOP, false, tn); 4517 4518 val_t *v = xcalloc(1, sizeof(*v)); 4519 4520 if (tn == NULL) { 4521 lint_assert(seen_error); 4522 debug_step("constant node is null; returning 1 instead"); 4523 v->v_tspec = INT; 4524 v->u.integer = 1; 4525 return v; 4526 } 4527 4528 v->v_tspec = tn->tn_type->t_tspec; 4529 4530 if (tn->tn_op == CON) { 4531 lint_assert(tn->tn_type->t_tspec == tn->u.value.v_tspec); 4532 if (is_integer(tn->u.value.v_tspec)) { 4533 v->v_unsigned_since_c90 = 4534 tn->u.value.v_unsigned_since_c90; 4535 v->u.integer = tn->u.value.u.integer; 4536 return v; 4537 } 4538 v->u.integer = (int64_t)tn->u.value.u.floating; 4539 } else 4540 v->u.integer = 1; 4541 4542 if (required) 4543 /* integral constant expression expected */ 4544 error(55); 4545 else 4546 /* variable array dimension is a C99/GCC extension */ 4547 c99ism(318); 4548 4549 if (!is_integer(v->v_tspec)) 4550 v->v_tspec = INT; 4551 4552 return v; 4553 } 4554 4555 static bool 4556 is_constcond_false(const tnode_t *tn, tspec_t t) 4557 { 4558 return (t == BOOL || t == INT) && 4559 tn->tn_op == CON && tn->u.value.u.integer == 0; 4560 } 4561 4562 /* 4563 * Perform some tests on expressions which can't be done in build_binary() 4564 * and functions called by build_binary(). These tests must be done here 4565 * because we need some information about the context in which the operations 4566 * are performed. 4567 * After all tests are performed and dofreeblk is true, expr() frees the 4568 * memory which is used for the expression. 4569 */ 4570 void 4571 expr(tnode_t *tn, bool vctx, bool cond, bool dofreeblk, bool is_do_while, 4572 const char *stmt_kind) 4573 { 4574 4575 if (tn == NULL) { /* in case of errors */ 4576 expr_free_all(); 4577 return; 4578 } 4579 4580 /* expr() is also called in global initializations */ 4581 if (dcs->d_kind != DLK_EXTERN && !is_do_while) 4582 check_statement_reachable(stmt_kind); 4583 4584 check_expr_misc(tn, vctx, cond, !cond, false, false, false); 4585 if (tn->tn_op == ASSIGN && !tn->tn_parenthesized) { 4586 if (hflag && cond) 4587 /* assignment in conditional context */ 4588 warning(159); 4589 } else if (tn->tn_op == CON) { 4590 if (hflag && cond && !suppress_constcond && 4591 !tn->tn_system_dependent && 4592 !(is_do_while && 4593 is_constcond_false(tn, tn->tn_type->t_tspec))) 4594 /* constant in conditional context */ 4595 warning(161); 4596 } 4597 if (!modtab[tn->tn_op].m_has_side_effect) { 4598 /* 4599 * for left operands of COMMA this warning is already printed 4600 */ 4601 if (tn->tn_op != COMMA && !vctx && !cond) 4602 check_null_effect(tn); 4603 } 4604 debug_node(tn); 4605 4606 if (dofreeblk) 4607 expr_free_all(); 4608 } 4609 4610 /* If the expression has the form '*(arr + idx)', check the array index. */ 4611 static void 4612 check_array_index(const tnode_t *indir, bool taking_address) 4613 { 4614 const tnode_t *plus, *arr, *idx; 4615 4616 if (indir->tn_op == INDIR 4617 && (plus = indir->u.ops.left, plus->tn_op == PLUS) 4618 && plus->u.ops.left->tn_op == ADDR 4619 && (arr = plus->u.ops.left->u.ops.left, true) 4620 && (arr->tn_op == STRING || arr->tn_op == NAME) 4621 && arr->tn_type->t_tspec == ARRAY 4622 && (idx = plus->u.ops.right, idx->tn_op == CON) 4623 && (!is_incomplete(arr->tn_type) || idx->u.value.u.integer < 0)) 4624 goto proceed; 4625 return; 4626 4627 proceed:; 4628 int elsz = length_in_bits(arr->tn_type->t_subt, NULL); 4629 if (elsz == 0) 4630 return; 4631 elsz /= CHAR_SIZE; 4632 4633 /* Change the unit of the index from bytes to element size. */ 4634 int64_t con = is_uinteger(idx->tn_type->t_tspec) 4635 ? (int64_t)((uint64_t)idx->u.value.u.integer / elsz) 4636 : idx->u.value.u.integer / elsz; 4637 4638 int dim = arr->tn_type->u.dimension + (taking_address ? 1 : 0); 4639 4640 if (!is_uinteger(idx->tn_type->t_tspec) && con < 0) 4641 /* array subscript %jd cannot be negative */ 4642 warning(167, (intmax_t)con); 4643 else if (dim > 0 && (uint64_t)con >= (uint64_t)dim) 4644 /* array subscript %ju cannot be > %d */ 4645 warning(168, (uintmax_t)con, dim - 1); 4646 } 4647 4648 static void 4649 check_expr_addr(const tnode_t *ln, bool szof, bool fcall) 4650 { 4651 /* XXX: Taking warn_about_unreachable into account here feels wrong. */ 4652 if (ln->tn_op == NAME && (reached || !warn_about_unreachable)) { 4653 if (!szof) 4654 mark_as_set(ln->u.sym); 4655 mark_as_used(ln->u.sym, fcall, szof); 4656 } 4657 check_array_index(ln, true); 4658 } 4659 4660 /* 4661 * If there is an asm statement in one of the compound statements around, 4662 * there may be other side effects, so don't warn. 4663 */ 4664 static bool 4665 is_asm_around(void) 4666 { 4667 for (decl_level *dl = dcs; dl != NULL; dl = dl->d_enclosing) 4668 if (dl->d_asm) 4669 return true; 4670 return false; 4671 } 4672 4673 static void 4674 check_expr_side_effect(const tnode_t *ln, bool szof) 4675 { 4676 4677 /* XXX: Taking warn_about_unreachable into account here feels wrong. */ 4678 if (ln->tn_op == NAME && (reached || !warn_about_unreachable)) { 4679 scl_t sc = ln->u.sym->s_scl; 4680 if (sc != EXTERN && sc != STATIC && 4681 !ln->u.sym->s_set && !szof && !is_asm_around()) { 4682 /* '%s' may be used before set */ 4683 warning(158, ln->u.sym->s_name); 4684 mark_as_set(ln->u.sym); 4685 } 4686 mark_as_used(ln->u.sym, false, false); 4687 } 4688 } 4689 4690 static void 4691 check_expr_assign(const tnode_t *ln, bool szof) 4692 { 4693 /* XXX: Taking warn_about_unreachable into account here feels wrong. */ 4694 if (ln->tn_op == NAME && !szof && (reached || !warn_about_unreachable)) { 4695 mark_as_set(ln->u.sym); 4696 if (ln->u.sym->s_scl == EXTERN) 4697 outusg(ln->u.sym); 4698 } 4699 check_array_index(ln, false); 4700 } 4701 4702 static void 4703 check_expr_call(const tnode_t *tn, const tnode_t *ln, 4704 bool szof, bool vctx, bool cond, bool retval_discarded) 4705 { 4706 lint_assert(ln->tn_op == ADDR); 4707 lint_assert(ln->u.ops.left->tn_op == NAME); 4708 if (!szof && !is_compiler_builtin(ln->u.ops.left->u.sym->s_name)) 4709 outcall(tn, vctx || cond, retval_discarded); 4710 4711 const function_call *call = tn->u.call; 4712 if (call->args_len == 4 || call->args_len == 5) 4713 check_snprintb(call); 4714 } 4715 4716 static void 4717 check_expr_op(op_t op, const tnode_t *ln, bool szof, bool fcall, bool eqwarn) 4718 { 4719 switch (op) { 4720 case ADDR: 4721 check_expr_addr(ln, szof, fcall); 4722 break; 4723 case LOAD: 4724 check_array_index(ln, false); 4725 /* FALLTHROUGH */ 4726 case INCBEF: 4727 case DECBEF: 4728 case INCAFT: 4729 case DECAFT: 4730 case ADDASS: 4731 case SUBASS: 4732 case MULASS: 4733 case DIVASS: 4734 case MODASS: 4735 case ANDASS: 4736 case ORASS: 4737 case XORASS: 4738 case SHLASS: 4739 case SHRASS: 4740 case REAL: 4741 case IMAG: 4742 check_expr_side_effect(ln, szof); 4743 break; 4744 case ASSIGN: 4745 check_expr_assign(ln, szof); 4746 break; 4747 case EQ: 4748 if (hflag && eqwarn) 4749 /* operator '==' found where '=' was expected */ 4750 warning(160); 4751 break; 4752 default: 4753 break; 4754 } 4755 } 4756 4757 /* 4758 * vctx ??? 4759 * cond whether the expression is a condition that 4760 * will be compared with 0 4761 * eqwarn whether the operator '==' might be a 4762 * misspelled '=' 4763 * fcall whether the expression is a function call 4764 * retval_discarded whether the return value of a function call 4765 * is discarded; such calls will be analyzed by 4766 * lint2 in messages 4, 8 and 9 4767 * szof whether the expression is part of a sizeof 4768 * expression, which means that its value is 4769 * discarded since only the type is relevant 4770 */ 4771 void 4772 check_expr_misc(const tnode_t *tn, bool vctx, bool cond, 4773 bool eqwarn, bool fcall, bool retval_discarded, bool szof) 4774 { 4775 4776 if (tn == NULL) 4777 return; 4778 op_t op = tn->tn_op; 4779 if (op == NAME || op == CON || op == STRING) 4780 return; 4781 bool is_direct = op == CALL 4782 && tn->u.call->func->tn_op == ADDR 4783 && tn->u.call->func->u.ops.left->tn_op == NAME; 4784 if (op == CALL) { 4785 const function_call *call = tn->u.call; 4786 if (is_direct) 4787 check_expr_call(tn, call->func, 4788 szof, vctx, cond, retval_discarded); 4789 bool discard = op == CVT && tn->tn_type->t_tspec == VOID; 4790 check_expr_misc(call->func, false, false, false, is_direct, 4791 discard, szof); 4792 for (size_t i = 0, n = call->args_len; i < n; i++) 4793 check_expr_misc(call->args[i], 4794 true, false, false, false, false, szof); 4795 return; 4796 } 4797 4798 lint_assert(has_operands(tn)); 4799 tnode_t *ln = tn->u.ops.left; 4800 tnode_t *rn = tn->u.ops.right; 4801 check_expr_op(op, ln, szof, fcall, eqwarn); 4802 4803 const mod_t *mp = &modtab[op]; 4804 bool cvctx = mp->m_value_context; 4805 bool ccond = mp->m_compares_with_zero; 4806 bool eq = mp->m_warn_if_operand_eq && 4807 !ln->tn_parenthesized && 4808 rn != NULL && !rn->tn_parenthesized; 4809 4810 /* 4811 * Values of operands of ':' are not used if the type of at least 4812 * one of the operands (for GCC compatibility) is 'void'. 4813 * 4814 * XXX test/value context of QUEST should probably be used as 4815 * context for both operands of COLON. 4816 */ 4817 if (op == COLON && tn->tn_type->t_tspec == VOID) 4818 cvctx = ccond = false; 4819 bool discard = op == CVT && tn->tn_type->t_tspec == VOID; 4820 check_expr_misc(ln, cvctx, ccond, eq, is_direct, discard, szof); 4821 4822 switch (op) { 4823 case LOGAND: 4824 case LOGOR: 4825 check_expr_misc(rn, false, true, eq, false, false, szof); 4826 break; 4827 case COLON: 4828 check_expr_misc(rn, cvctx, ccond, eq, false, false, szof); 4829 break; 4830 case COMMA: 4831 check_expr_misc(rn, vctx, cond, false, false, false, szof); 4832 break; 4833 default: 4834 if (mp->m_binary) 4835 check_expr_misc(rn, true, false, eq, false, false, 4836 szof); 4837 break; 4838 } 4839 } 4840 4841 /* 4842 * Return whether the expression can be used for static initialization. 4843 * 4844 * Constant initialization expressions must be constant or an address 4845 * of a static object with an optional offset. In the first case, 4846 * the result is returned in *offsp. In the second case, the static 4847 * object is returned in *symp and the offset in *offsp. 4848 * 4849 * The expression can consist of PLUS, MINUS, ADDR, NAME, STRING and 4850 * CON. Type conversions are allowed if they do not change binary 4851 * representation (including width). 4852 * 4853 * C99 6.6 "Constant expressions" 4854 * C99 6.7.8p4 restricts initializers for static storage duration 4855 */ 4856 bool 4857 constant_addr(const tnode_t *tn, const sym_t **symp, ptrdiff_t *offsp) 4858 { 4859 const sym_t *sym; 4860 ptrdiff_t offs1, offs2; 4861 tspec_t t, ot; 4862 4863 switch (tn->tn_op) { 4864 case MINUS: 4865 if (tn->u.ops.right->tn_op == CVT) 4866 return constant_addr(tn->u.ops.right, symp, offsp); 4867 else if (tn->u.ops.right->tn_op != CON) 4868 return false; 4869 /* FALLTHROUGH */ 4870 case PLUS: 4871 offs1 = offs2 = 0; 4872 if (tn->u.ops.left->tn_op == CON) { 4873 offs1 = (ptrdiff_t)tn->u.ops.left->u.value.u.integer; 4874 if (!constant_addr(tn->u.ops.right, &sym, &offs2)) 4875 return false; 4876 } else if (tn->u.ops.right->tn_op == CON) { 4877 offs2 = (ptrdiff_t)tn->u.ops.right->u.value.u.integer; 4878 if (tn->tn_op == MINUS) 4879 offs2 = -offs2; 4880 if (!constant_addr(tn->u.ops.left, &sym, &offs1)) 4881 return false; 4882 } else { 4883 return false; 4884 } 4885 *symp = sym; 4886 *offsp = offs1 + offs2; 4887 return true; 4888 case ADDR: 4889 if (tn->u.ops.left->tn_op == NAME) { 4890 *symp = tn->u.ops.left->u.sym; 4891 *offsp = 0; 4892 return true; 4893 } else { 4894 /* 4895 * If this were the front end of a compiler, we would 4896 * return a label instead of 0, at least if 4897 * 'tn->u.ops.left->tn_op == STRING'. 4898 */ 4899 *symp = NULL; 4900 *offsp = 0; 4901 return true; 4902 } 4903 case CVT: 4904 t = tn->tn_type->t_tspec; 4905 ot = tn->u.ops.left->tn_type->t_tspec; 4906 if ((!is_integer(t) && t != PTR) || 4907 (!is_integer(ot) && ot != PTR)) { 4908 return false; 4909 } 4910 #if 0 4911 /*- 4912 * consider: 4913 * struct foo { 4914 * unsigned char a; 4915 * } f = { 4916 * (unsigned char)(unsigned long) 4917 * (&(((struct foo *)0)->a)) 4918 * }; 4919 * since psize(unsigned long) != psize(unsigned char), 4920 * this fails. 4921 */ 4922 else if (psize(t) != psize(ot)) 4923 return -1; 4924 #endif 4925 return constant_addr(tn->u.ops.left, symp, offsp); 4926 default: 4927 return false; 4928 } 4929 } 4930 4931 /* Append s2 to s1, then free s2. */ 4932 buffer * 4933 cat_strings(buffer *s1, buffer *s2) 4934 { 4935 4936 if ((s1->data != NULL) != (s2->data != NULL)) { 4937 /* cannot concatenate wide and regular string literals */ 4938 error(292); 4939 return s1; 4940 } 4941 4942 if (s1->data != NULL) { 4943 while (s1->len + s2->len + 1 > s1->cap) 4944 s1->cap *= 2; 4945 s1->data = xrealloc(s1->data, s1->cap); 4946 memcpy(s1->data + s1->len, s2->data, s2->len + 1); 4947 free(s2->data); 4948 } 4949 s1->len += s2->len; 4950 free(s2); 4951 4952 return s1; 4953 } 4954 4955 4956 typedef struct stmt_expr { 4957 memory_pool se_mem; 4958 sym_t *se_sym; 4959 struct stmt_expr *se_enclosing; 4960 } stmt_expr; 4961 4962 static stmt_expr *stmt_exprs; 4963 4964 void 4965 begin_statement_expr(void) 4966 { 4967 debug_enter(); 4968 4969 stmt_expr *se = xmalloc(sizeof(*se)); 4970 se->se_mem = expr_save_memory(); 4971 se->se_sym = NULL; 4972 se->se_enclosing = stmt_exprs; 4973 stmt_exprs = se; 4974 } 4975 4976 void 4977 do_statement_expr(tnode_t *tn) 4978 { 4979 block_level--; 4980 mem_block_level--; 4981 stmt_exprs->se_sym = tn != NULL 4982 ? mktempsym(block_dup_type(tn->tn_type)) 4983 : NULL; /* after a syntax error */ 4984 mem_block_level++; 4985 block_level++; 4986 /* '({ ... })' is a GCC extension */ 4987 gnuism(320); 4988 } 4989 4990 tnode_t * 4991 end_statement_expr(void) 4992 { 4993 tnode_t *tn; 4994 4995 stmt_expr *se = stmt_exprs; 4996 if (se->se_sym == NULL) { 4997 tn = NULL; /* after a syntax error */ 4998 goto end; 4999 } 5000 5001 tn = build_name(se->se_sym, false); 5002 (void)expr_save_memory(); /* leak */ 5003 expr_restore_memory(se->se_mem); 5004 stmt_exprs = se->se_enclosing; 5005 free(se); 5006 5007 end: 5008 debug_leave(); 5009 return tn; 5010 } 5011 5012 bool 5013 in_statement_expr(void) 5014 { 5015 return stmt_exprs != NULL; 5016 } 5017
Indexes created Fri Sep 26 08:10:20 GMT 2025