tree.c revision 1.465
1 /* $NetBSD: tree.c,v 1.465 2022/07/01 19:52:41 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 1.465 2022/07/01 19:52:41 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 typedef struct integer_constraints { 53 int64_t smin; /* signed minimum */ 54 int64_t smax; /* signed maximum */ 55 uint64_t umin; /* unsigned minimum */ 56 uint64_t umax; /* unsigned maximum */ 57 uint64_t bset; /* bits that are definitely set */ 58 uint64_t bclr; /* bits that are definitely clear */ 59 } integer_constraints; 60 61 static tnode_t *build_integer_constant(tspec_t, int64_t); 62 static void check_pointer_comparison(op_t, 63 const tnode_t *, const tnode_t *); 64 static bool check_assign_types_compatible(op_t, int, 65 const tnode_t *, const tnode_t *); 66 static void check_bad_enum_operation(op_t, 67 const tnode_t *, const tnode_t *); 68 static void check_enum_type_mismatch(op_t, int, 69 const tnode_t *, const tnode_t *); 70 static void check_enum_int_mismatch(op_t, int, 71 const tnode_t *, const tnode_t *); 72 static tnode_t *new_tnode(op_t, bool, type_t *, tnode_t *, tnode_t *); 73 static void balance(op_t, tnode_t **, tnode_t **); 74 static void warn_incompatible_types(op_t, const type_t *, tspec_t, 75 const type_t *, tspec_t); 76 static void warn_incompatible_pointers(const mod_t *, 77 const type_t *, const type_t *); 78 static bool has_constant_member(const type_t *); 79 static void check_prototype_conversion(int, tspec_t, tspec_t, type_t *, 80 tnode_t *); 81 static void convert_integer_from_integer(op_t, int, tspec_t, tspec_t, 82 type_t *, tnode_t *); 83 static void convert_integer_from_pointer(op_t, tspec_t, type_t *, 84 tnode_t *); 85 static void convert_pointer_from_pointer(type_t *, tnode_t *); 86 static tnode_t *build_struct_access(op_t, bool, tnode_t *, tnode_t *); 87 static tnode_t *build_prepost_incdec(op_t, bool, tnode_t *); 88 static tnode_t *build_real_imag(op_t, bool, tnode_t *); 89 static tnode_t *build_address(bool, tnode_t *, bool); 90 static tnode_t *build_plus_minus(op_t, bool, tnode_t *, tnode_t *); 91 static tnode_t *build_bit_shift(op_t, bool, tnode_t *, tnode_t *); 92 static tnode_t *build_colon(bool, tnode_t *, tnode_t *); 93 static tnode_t *build_assignment(op_t, bool, tnode_t *, tnode_t *); 94 static tnode_t *subt_size_in_bytes(type_t *); 95 static tnode_t *fold(tnode_t *); 96 static tnode_t *fold_bool(tnode_t *); 97 static tnode_t *fold_float(tnode_t *); 98 static tnode_t *check_function_arguments(type_t *, tnode_t *); 99 static tnode_t *check_prototype_argument(int, type_t *, tnode_t *); 100 static void check_null_effect(const tnode_t *); 101 static void check_array_index(tnode_t *, bool); 102 static void check_integer_comparison(op_t, tnode_t *, tnode_t *); 103 static void check_precedence_confusion(tnode_t *); 104 105 extern sig_atomic_t fpe; 106 107 static bool 108 ic_maybe_signed(const type_t *tp, const integer_constraints *ic) 109 { 110 111 return !is_uinteger(tp->t_tspec) && 112 (ic->bclr & ((uint64_t)1 << 63)) == 0; 113 } 114 115 static unsigned 116 ic_length_in_bits(const type_t *tp) 117 { 118 119 lint_assert(is_integer(tp->t_tspec)); 120 return tp->t_bitfield ? tp->t_flen : size_in_bits(tp->t_tspec); 121 } 122 123 static integer_constraints 124 ic_any(const type_t *tp) 125 { 126 integer_constraints c; 127 128 uint64_t vbits = value_bits(ic_length_in_bits(tp)); 129 if (is_uinteger(tp->t_tspec)) { 130 c.smin = INT64_MIN; 131 c.smax = INT64_MAX; 132 c.umin = 0; 133 c.umax = vbits; 134 c.bset = 0; 135 c.bclr = ~c.umax; 136 } else { 137 c.smin = (int64_t)-1 - (int64_t)(vbits >> 1); 138 c.smax = (int64_t)(vbits >> 1); 139 c.umin = 0; 140 c.umax = UINT64_MAX; 141 c.bset = 0; 142 c.bclr = 0; 143 } 144 return c; 145 } 146 147 static integer_constraints 148 ic_con(const type_t *tp, const val_t *v) 149 { 150 integer_constraints c; 151 152 lint_assert(is_integer(tp->t_tspec)); 153 int64_t s = v->v_quad; 154 uint64_t u = (uint64_t)s; 155 c.smin = s; 156 c.smax = s; 157 c.umin = u; 158 c.umax = u; 159 c.bset = u; 160 c.bclr = ~u; 161 return c; 162 } 163 164 static integer_constraints 165 ic_cvt(const type_t *ntp, const type_t *otp, integer_constraints a) 166 { 167 168 if (ic_length_in_bits(ntp) > ic_length_in_bits(otp) && 169 is_uinteger(otp->t_tspec)) 170 return a; 171 return ic_any(ntp); 172 } 173 174 static integer_constraints 175 ic_bitand(integer_constraints a, integer_constraints b) 176 { 177 integer_constraints c; 178 179 c.smin = INT64_MIN; 180 c.smax = INT64_MAX; 181 c.umin = 0; 182 c.umax = UINT64_MAX; 183 c.bset = a.bset & b.bset; 184 c.bclr = a.bclr | b.bclr; 185 return c; 186 } 187 188 static integer_constraints 189 ic_bitor(integer_constraints a, integer_constraints b) 190 { 191 integer_constraints c; 192 193 c.smin = INT64_MIN; 194 c.smax = INT64_MAX; 195 c.umin = 0; 196 c.umax = UINT64_MAX; 197 c.bset = a.bset | b.bset; 198 c.bclr = a.bclr & b.bclr; 199 return c; 200 } 201 202 static integer_constraints 203 ic_shl(const type_t *tp, integer_constraints a, integer_constraints b) 204 { 205 integer_constraints c; 206 unsigned int amount; 207 208 if (ic_maybe_signed(tp, &a)) 209 return ic_any(tp); 210 211 if (b.smin == b.smax && b.smin >= 0 && b.smin < 64) 212 amount = (unsigned int)b.smin; 213 else if (b.umin == b.umax && b.umin < 64) 214 amount = (unsigned int)b.umin; 215 else 216 return ic_any(tp); 217 218 c.smin = INT64_MIN; 219 c.smax = INT64_MAX; 220 c.umin = 0; 221 c.umax = UINT64_MAX; 222 c.bset = a.bset << amount; 223 c.bclr = a.bclr << amount | (((uint64_t)1 << amount) - 1); 224 return c; 225 } 226 227 static integer_constraints 228 ic_shr(const type_t *tp, integer_constraints a, integer_constraints b) 229 { 230 integer_constraints c; 231 unsigned int amount; 232 233 if (ic_maybe_signed(tp, &a)) 234 return ic_any(tp); 235 236 if (b.smin == b.smax && b.smin >= 0 && b.smin < 64) 237 amount = (unsigned int)b.smin; 238 else if (b.umin == b.umax && b.umin < 64) 239 amount = (unsigned int)b.umin; 240 else 241 return ic_any(tp); 242 243 c.smin = INT64_MIN; 244 c.smax = INT64_MAX; 245 c.umin = 0; 246 c.umax = UINT64_MAX; 247 c.bset = a.bset >> amount; 248 c.bclr = a.bclr >> amount | ~(~(uint64_t)0 >> amount); 249 return c; 250 } 251 252 static integer_constraints 253 ic_expr(const tnode_t *tn) 254 { 255 integer_constraints lc, rc; 256 257 lint_assert(is_integer(tn->tn_type->t_tspec)); 258 259 switch (tn->tn_op) { 260 case CON: 261 return ic_con(tn->tn_type, tn->tn_val); 262 case CVT: 263 if (!is_integer(tn->tn_left->tn_type->t_tspec)) 264 return ic_any(tn->tn_type); 265 lc = ic_expr(tn->tn_left); 266 return ic_cvt(tn->tn_type, tn->tn_left->tn_type, lc); 267 case SHL: 268 lc = ic_expr(tn->tn_left); 269 rc = ic_expr(tn->tn_right); 270 return ic_shl(tn->tn_type, lc, rc); 271 case SHR: 272 lc = ic_expr(tn->tn_left); 273 rc = ic_expr(tn->tn_right); 274 return ic_shr(tn->tn_type, lc, rc); 275 case BITAND: 276 lc = ic_expr(tn->tn_left); 277 rc = ic_expr(tn->tn_right); 278 return ic_bitand(lc, rc); 279 case BITOR: 280 lc = ic_expr(tn->tn_left); 281 rc = ic_expr(tn->tn_right); 282 return ic_bitor(lc, rc); 283 default: 284 return ic_any(tn->tn_type); 285 } 286 } 287 288 static const char * 289 op_name(op_t op) 290 { 291 return modtab[op].m_name; 292 } 293 294 /* Build 'pointer to tp', 'array of tp' or 'function returning tp'. */ 295 type_t * 296 block_derive_type(type_t *tp, tspec_t t) 297 { 298 type_t *tp2; 299 300 tp2 = block_zero_alloc(sizeof(*tp2)); 301 tp2->t_tspec = t; 302 tp2->t_subt = tp; 303 return tp2; 304 } 305 306 /* 307 * Derive 'pointer to tp' or 'function returning tp'. 308 * The memory is freed at the end of the current expression. 309 */ 310 type_t * 311 expr_derive_type(type_t *tp, tspec_t t) 312 { 313 type_t *tp2; 314 315 tp2 = expr_zero_alloc(sizeof(*tp2)); 316 tp2->t_tspec = t; 317 tp2->t_subt = tp; 318 return tp2; 319 } 320 321 /* 322 * Create a node for a constant. 323 */ 324 tnode_t * 325 build_constant(type_t *tp, val_t *v) 326 { 327 tnode_t *n; 328 329 n = expr_alloc_tnode(); 330 n->tn_op = CON; 331 n->tn_type = tp; 332 n->tn_val = expr_zero_alloc(sizeof(*n->tn_val)); 333 n->tn_val->v_tspec = tp->t_tspec; 334 n->tn_val->v_unsigned_since_c90 = v->v_unsigned_since_c90; 335 n->tn_val->v_u = v->v_u; 336 free(v); 337 return n; 338 } 339 340 static tnode_t * 341 build_integer_constant(tspec_t t, int64_t q) 342 { 343 tnode_t *n; 344 345 n = expr_alloc_tnode(); 346 n->tn_op = CON; 347 n->tn_type = gettyp(t); 348 n->tn_val = expr_zero_alloc(sizeof(*n->tn_val)); 349 n->tn_val->v_tspec = t; 350 n->tn_val->v_quad = q; 351 return n; 352 } 353 354 static void 355 fallback_symbol(sym_t *sym) 356 { 357 358 if (fallback_symbol_strict_bool(sym)) 359 return; 360 361 if (block_level > 0 && (strcmp(sym->s_name, "__FUNCTION__") == 0 || 362 strcmp(sym->s_name, "__PRETTY_FUNCTION__") == 0)) { 363 /* __FUNCTION__/__PRETTY_FUNCTION__ is a GCC extension */ 364 gnuism(316); 365 sym->s_type = block_derive_type(gettyp(CHAR), PTR); 366 sym->s_type->t_const = true; 367 return; 368 } 369 370 if (block_level > 0 && strcmp(sym->s_name, "__func__") == 0) { 371 if (!allow_c99) 372 /* __func__ is a C99 feature */ 373 warning(317); 374 sym->s_type = block_derive_type(gettyp(CHAR), PTR); 375 sym->s_type->t_const = true; 376 return; 377 } 378 379 /* '%s' undefined */ 380 error(99, sym->s_name); 381 } 382 383 /* 384 * Functions that are predeclared by GCC or other compilers can be called 385 * with arbitrary arguments. Since lint usually runs after a successful 386 * compilation, it's the compiler's job to catch any errors. 387 */ 388 bool 389 is_compiler_builtin(const char *name) 390 { 391 /* https://gcc.gnu.org/onlinedocs/gcc/C-Extensions.html */ 392 if (allow_gcc) { 393 if (strncmp(name, "__atomic_", 9) == 0 || 394 strncmp(name, "__builtin_", 10) == 0 || 395 strcmp(name, "alloca") == 0 || 396 /* obsolete but still in use, as of 2021 */ 397 strncmp(name, "__sync_", 7) == 0) 398 return true; 399 } 400 401 /* https://software.intel.com/sites/landingpage/IntrinsicsGuide/ */ 402 if (strncmp(name, "_mm_", 4) == 0) 403 return true; 404 405 return false; 406 } 407 408 static bool 409 str_endswith(const char *haystack, const char *needle) 410 { 411 size_t hlen = strlen(haystack); 412 size_t nlen = strlen(needle); 413 414 return nlen <= hlen && 415 memcmp(haystack + hlen - nlen, needle, nlen) == 0; 416 } 417 418 /* https://gcc.gnu.org/onlinedocs/gcc/Integer-Overflow-Builtins.html */ 419 static bool 420 is_gcc_bool_builtin(const char *name) 421 { 422 return strncmp(name, "__builtin_", 10) == 0 && 423 (str_endswith(name, "_overflow") || 424 str_endswith(name, "_overflow_p")); 425 } 426 427 static void 428 build_name_call(sym_t *sym) 429 { 430 431 if (is_compiler_builtin(sym->s_name)) { 432 /* 433 * Do not warn about these, just assume that 434 * they are regular functions compatible with 435 * non-prototype calling conventions. 436 */ 437 if (allow_gcc && is_gcc_bool_builtin(sym->s_name)) 438 sym->s_type = gettyp(BOOL); 439 440 } else if (allow_c99) { 441 /* function '%s' implicitly declared to return int */ 442 error(215, sym->s_name); 443 } else if (!allow_trad) { 444 /* function '%s' implicitly declared to return int */ 445 warning(215, sym->s_name); 446 } 447 448 /* XXX if !allow_c90, the symbol should be exported to level 0 */ 449 sym->s_type = block_derive_type(sym->s_type, FUNC); 450 } 451 452 /* Create a node for a name (symbol table entry). */ 453 tnode_t * 454 build_name(sym_t *sym, bool is_funcname) 455 { 456 tnode_t *n; 457 458 if (sym->s_scl == NOSCL) { 459 sym->s_scl = EXTERN; 460 sym->s_def = DECL; 461 if (is_funcname) 462 build_name_call(sym); 463 else 464 fallback_symbol(sym); 465 } 466 467 lint_assert(sym->s_kind == FVFT || sym->s_kind == FMEMBER); 468 469 n = expr_alloc_tnode(); 470 n->tn_type = sym->s_type; 471 if (sym->s_scl == BOOL_CONST) { 472 n->tn_op = CON; 473 n->tn_val = expr_zero_alloc(sizeof(*n->tn_val)); 474 n->tn_val->v_tspec = BOOL; 475 n->tn_val->v_quad = sym->u.s_bool_constant ? 1 : 0; 476 } else if (sym->s_scl == ENUM_CONST) { 477 n->tn_op = CON; 478 n->tn_val = expr_zero_alloc(sizeof(*n->tn_val)); 479 n->tn_val->v_tspec = INT; /* ENUM is in n->tn_type */ 480 n->tn_val->v_quad = sym->u.s_enum_constant; 481 } else { 482 n->tn_op = NAME; 483 n->tn_sym = sym; 484 if (sym->s_kind == FVFT && sym->s_type->t_tspec != FUNC) 485 n->tn_lvalue = true; 486 } 487 488 return n; 489 } 490 491 tnode_t * 492 build_string(strg_t *strg) 493 { 494 size_t len; 495 tnode_t *n; 496 type_t *tp; 497 498 len = strg->st_len; 499 500 n = expr_alloc_tnode(); 501 502 tp = expr_zero_alloc(sizeof(*tp)); 503 tp->t_tspec = ARRAY; 504 tp->t_subt = gettyp(strg->st_char ? CHAR : WCHAR); 505 tp->t_dim = (int)(len + 1); 506 507 n->tn_op = STRING; 508 n->tn_type = tp; 509 n->tn_lvalue = true; 510 511 n->tn_string = expr_zero_alloc(sizeof(*n->tn_string)); 512 n->tn_string->st_char = strg->st_char; 513 n->tn_string->st_len = len; 514 515 size_t chsize = strg->st_char ? sizeof(char) : sizeof(wchar_t); 516 size_t size = (len + 1) * chsize; 517 n->tn_string->st_mem = expr_zero_alloc(size); 518 (void)memcpy(n->tn_string->st_mem, strg->st_mem, size); 519 free(strg->st_mem); 520 free(strg); 521 522 return n; 523 } 524 525 /* 526 * Returns a symbol which has the same name as the msym argument and is a 527 * member of the struct or union specified by the tn argument. 528 */ 529 static sym_t * 530 struct_or_union_member(tnode_t *tn, op_t op, sym_t *msym) 531 { 532 struct_or_union *str; 533 type_t *tp; 534 sym_t *sym, *csym; 535 bool eq; 536 tspec_t t; 537 538 /* 539 * Remove the member if it was unknown until now, which means 540 * that no defined struct or union has a member with the same name. 541 */ 542 if (msym->s_scl == NOSCL) { 543 /* type '%s' does not have member '%s' */ 544 error(101, type_name(tn->tn_type), msym->s_name); 545 rmsym(msym); 546 msym->s_kind = FMEMBER; 547 msym->s_scl = MOS; 548 549 struct_or_union *sou = expr_zero_alloc(sizeof(*sou)); 550 sou->sou_tag = expr_zero_alloc(sizeof(*sou->sou_tag)); 551 sou->sou_tag->s_name = unnamed; 552 553 msym->u.s_member.sm_sou_type = sou; 554 /* 555 * The member sm_offset_in_bits is not needed here since this 556 * symbol can only be used for error reporting. 557 */ 558 return msym; 559 } 560 561 /* Set str to the tag of which msym is expected to be a member. */ 562 str = NULL; 563 t = (tp = tn->tn_type)->t_tspec; 564 if (op == POINT) { 565 if (is_struct_or_union(t)) 566 str = tp->t_str; 567 } else if (op == ARROW && t == PTR) { 568 t = (tp = tp->t_subt)->t_tspec; 569 if (is_struct_or_union(t)) 570 str = tp->t_str; 571 } 572 573 /* 574 * If this struct/union has a member with the name of msym, return it. 575 */ 576 if (str != NULL) { 577 for (sym = msym; sym != NULL; sym = sym->s_symtab_next) { 578 if (!is_member(sym)) 579 continue; 580 if (sym->u.s_member.sm_sou_type != str) 581 continue; 582 if (strcmp(sym->s_name, msym->s_name) != 0) 583 continue; 584 return sym; 585 } 586 } 587 588 /* 589 * Set eq to false if there are struct/union members with the same 590 * name and different types and/or offsets. 591 */ 592 eq = true; 593 for (csym = msym; csym != NULL; csym = csym->s_symtab_next) { 594 if (csym->s_scl != MOS && csym->s_scl != MOU) 595 continue; 596 if (strcmp(msym->s_name, csym->s_name) != 0) 597 continue; 598 for (sym = csym->s_symtab_next; sym != NULL; 599 sym = sym->s_symtab_next) { 600 bool w; 601 602 if (sym->s_scl != MOS && sym->s_scl != MOU) 603 continue; 604 if (strcmp(csym->s_name, sym->s_name) != 0) 605 continue; 606 if (csym->u.s_member.sm_offset_in_bits != 607 sym->u.s_member.sm_offset_in_bits) { 608 eq = false; 609 break; 610 } 611 w = false; 612 eq = eqtype(csym->s_type, sym->s_type, 613 false, false, &w) && !w; 614 if (!eq) 615 break; 616 if (csym->s_bitfield != sym->s_bitfield) { 617 eq = false; 618 break; 619 } 620 if (csym->s_bitfield) { 621 type_t *tp1, *tp2; 622 623 tp1 = csym->s_type; 624 tp2 = sym->s_type; 625 if (tp1->t_flen != tp2->t_flen) { 626 eq = false; 627 break; 628 } 629 if (tp1->t_foffs != tp2->t_foffs) { 630 eq = false; 631 break; 632 } 633 } 634 } 635 if (!eq) 636 break; 637 } 638 639 /* 640 * Now handle the case in which the left operand refers really 641 * to a struct/union, but the right operand is not member of it. 642 */ 643 if (str != NULL) { 644 if (eq && !allow_c90) { 645 /* illegal use of member '%s' */ 646 warning(102, msym->s_name); 647 } else { 648 /* illegal use of member '%s' */ 649 error(102, msym->s_name); 650 } 651 return msym; 652 } 653 654 /* 655 * Now the left operand of ARROW does not point to a struct/union 656 * or the left operand of POINT is no struct/union. 657 */ 658 if (eq) { 659 if (op == POINT) { 660 if (!allow_c90) { 661 /* left operand of '.' must be struct ... */ 662 warning(103, type_name(tn->tn_type)); 663 } else { 664 /* left operand of '.' must be struct ... */ 665 error(103, type_name(tn->tn_type)); 666 } 667 } else { 668 if (!allow_c90 && tn->tn_type->t_tspec == PTR) { 669 /* left operand of '->' must be pointer ... */ 670 warning(104, type_name(tn->tn_type)); 671 } else { 672 /* left operand of '->' must be pointer ... */ 673 error(104, type_name(tn->tn_type)); 674 } 675 } 676 } else { 677 if (!allow_c90) { 678 /* non-unique member requires struct/union %s */ 679 error(105, op == POINT ? "object" : "pointer"); 680 } else { 681 /* unacceptable operand of '%s' */ 682 error(111, op_name(op)); 683 } 684 } 685 686 return msym; 687 } 688 689 tnode_t * 690 build_generic_selection(const tnode_t *expr, 691 struct generic_association *sel) 692 { 693 tnode_t *default_result = NULL; 694 695 for (; sel != NULL; sel = sel->ga_prev) { 696 if (expr != NULL && 697 eqtype(sel->ga_arg, expr->tn_type, false, false, NULL)) 698 return sel->ga_result; 699 else if (sel->ga_arg == NULL) 700 default_result = sel->ga_result; 701 } 702 return default_result; 703 } 704 705 /* 706 * Create a tree node for a binary operator and its two operands. Also called 707 * for unary operators; in that case rn is NULL. 708 * 709 * Function calls, sizeof and casts are handled elsewhere. 710 */ 711 tnode_t * 712 build_binary(tnode_t *ln, op_t op, bool sys, tnode_t *rn) 713 { 714 const mod_t *mp; 715 tnode_t *ntn; 716 type_t *rettp; 717 718 mp = &modtab[op]; 719 720 /* If there was an error in one of the operands, return. */ 721 if (ln == NULL || (mp->m_binary && rn == NULL)) 722 return NULL; 723 724 /* 725 * Apply class conversions to the left operand, but only if its 726 * value is needed or it is compared with zero. 727 */ 728 if (mp->m_value_context || mp->m_compares_with_zero) 729 ln = cconv(ln); 730 /* 731 * The right operand is almost always in a test or value context, 732 * except if it is a struct or union member. 733 */ 734 if (mp->m_binary && op != ARROW && op != POINT) 735 rn = cconv(rn); 736 737 /* 738 * Print some warnings for comparisons of unsigned values with 739 * constants lower than or equal to null. This must be done 740 * before promote() because otherwise unsigned char and unsigned 741 * short would be promoted to int. Types are also tested to be 742 * CHAR, which would also become int. 743 */ 744 if (mp->m_comparison) 745 check_integer_comparison(op, ln, rn); 746 747 if (mp->m_value_context || mp->m_compares_with_zero) 748 ln = promote(op, false, ln); 749 if (mp->m_binary && op != ARROW && op != POINT && 750 op != ASSIGN && op != RETURN && op != INIT) { 751 rn = promote(op, false, rn); 752 } 753 754 /* 755 * If the result of the operation is different for signed or 756 * unsigned operands and one of the operands is signed only in 757 * ANSI C, print a warning. 758 */ 759 if (mp->m_warn_if_left_unsigned_in_c90 && 760 ln->tn_op == CON && ln->tn_val->v_unsigned_since_c90) { 761 /* ANSI C treats constant as unsigned, op '%s' */ 762 warning(218, mp->m_name); 763 ln->tn_val->v_unsigned_since_c90 = false; 764 } 765 if (mp->m_warn_if_right_unsigned_in_c90 && 766 rn->tn_op == CON && rn->tn_val->v_unsigned_since_c90) { 767 /* ANSI C treats constant as unsigned, op '%s' */ 768 warning(218, mp->m_name); 769 rn->tn_val->v_unsigned_since_c90 = false; 770 } 771 772 /* Make sure both operands are of the same type */ 773 if (mp->m_balance_operands || (!allow_c90 && (op == SHL || op == SHR))) 774 balance(op, &ln, &rn); 775 776 /* 777 * Check types for compatibility with the operation and mutual 778 * compatibility. Return if there are serious problems. 779 */ 780 if (!typeok(op, 0, ln, rn)) 781 return NULL; 782 783 /* And now create the node. */ 784 switch (op) { 785 case POINT: 786 case ARROW: 787 ntn = build_struct_access(op, sys, ln, rn); 788 break; 789 case INCAFT: 790 case DECAFT: 791 case INCBEF: 792 case DECBEF: 793 ntn = build_prepost_incdec(op, sys, ln); 794 break; 795 case ADDR: 796 ntn = build_address(sys, ln, false); 797 break; 798 case INDIR: 799 ntn = new_tnode(INDIR, sys, ln->tn_type->t_subt, ln, NULL); 800 break; 801 case PLUS: 802 case MINUS: 803 ntn = build_plus_minus(op, sys, ln, rn); 804 break; 805 case SHL: 806 case SHR: 807 ntn = build_bit_shift(op, sys, ln, rn); 808 break; 809 case COLON: 810 ntn = build_colon(sys, ln, rn); 811 break; 812 case ASSIGN: 813 case MULASS: 814 case DIVASS: 815 case MODASS: 816 case ADDASS: 817 case SUBASS: 818 case SHLASS: 819 case SHRASS: 820 case ANDASS: 821 case XORASS: 822 case ORASS: 823 case RETURN: 824 case INIT: 825 ntn = build_assignment(op, sys, ln, rn); 826 break; 827 case COMMA: 828 case QUEST: 829 ntn = new_tnode(op, sys, rn->tn_type, ln, rn); 830 break; 831 case REAL: 832 case IMAG: 833 ntn = build_real_imag(op, sys, ln); 834 break; 835 default: 836 rettp = mp->m_returns_bool 837 ? gettyp(Tflag ? BOOL : INT) : ln->tn_type; 838 lint_assert(mp->m_binary == (rn != NULL)); 839 ntn = new_tnode(op, sys, rettp, ln, rn); 840 break; 841 } 842 843 /* Return if an error occurred. */ 844 if (ntn == NULL) 845 return NULL; 846 847 /* Print a warning if precedence confusion is possible */ 848 if (mp->m_possible_precedence_confusion) 849 check_precedence_confusion(ntn); 850 851 /* 852 * Print a warning if one of the operands is in a context where 853 * it is compared with zero and if this operand is a constant. 854 */ 855 if (hflag && !constcond_flag && 856 mp->m_compares_with_zero && 857 (ln->tn_op == CON || 858 ((mp->m_binary && op != QUEST) && rn->tn_op == CON)) && 859 /* XXX: rn->tn_system_dependent should be checked as well */ 860 !ln->tn_system_dependent) { 861 /* constant in conditional context */ 862 warning(161); 863 } 864 865 /* Fold if the operator requires it */ 866 if (mp->m_fold_constant_operands) { 867 if (ln->tn_op == CON && (!mp->m_binary || rn->tn_op == CON)) { 868 if (mp->m_compares_with_zero) { 869 ntn = fold_bool(ntn); 870 } else if (is_floating(ntn->tn_type->t_tspec)) { 871 ntn = fold_float(ntn); 872 } else { 873 ntn = fold(ntn); 874 } 875 } else if (op == QUEST && ln->tn_op == CON) { 876 ntn = ln->tn_val->v_quad != 0 877 ? rn->tn_left : rn->tn_right; 878 } 879 } 880 881 return ntn; 882 } 883 884 tnode_t * 885 build_unary(op_t op, bool sys, tnode_t *tn) 886 { 887 return build_binary(tn, op, sys, NULL); 888 } 889 890 tnode_t * 891 build_member_access(tnode_t *ln, op_t op, bool sys, sbuf_t *member) 892 { 893 sym_t *msym; 894 895 if (ln == NULL) 896 return NULL; 897 898 if (op == ARROW) { 899 /* must do this before struct_or_union_member is called */ 900 ln = cconv(ln); 901 } 902 msym = struct_or_union_member(ln, op, getsym(member)); 903 return build_binary(ln, op, sys, build_name(msym, false)); 904 } 905 906 /* 907 * Perform class conversions. 908 * 909 * Arrays of type T are converted into pointers to type T. 910 * Functions are converted to pointers to functions. 911 * Lvalues are converted to rvalues. 912 * 913 * C99 6.3 "Conversions" 914 * C99 6.3.2 "Other operands" 915 * C99 6.3.2.1 "Lvalues, arrays, and function designators" 916 */ 917 tnode_t * 918 cconv(tnode_t *tn) 919 { 920 type_t *tp; 921 922 /* 923 * Array-lvalue (array of type T) is converted into rvalue 924 * (pointer to type T) 925 */ 926 if (tn->tn_type->t_tspec == ARRAY) { 927 if (!tn->tn_lvalue) { 928 /* XXX print correct operator */ 929 /* %soperand of '%s' must be lvalue */ 930 gnuism(114, "", op_name(ADDR)); 931 } 932 tn = new_tnode(ADDR, tn->tn_sys, 933 expr_derive_type(tn->tn_type->t_subt, PTR), tn, NULL); 934 } 935 936 /* 937 * Expression of type function (function with return value of type T) 938 * in rvalue-expression (pointer to function with return value 939 * of type T) 940 */ 941 if (tn->tn_type->t_tspec == FUNC) 942 tn = build_address(tn->tn_sys, tn, true); 943 944 /* lvalue to rvalue */ 945 if (tn->tn_lvalue) { 946 tp = expr_dup_type(tn->tn_type); 947 /* C99 6.3.2.1p2 sentence 2 says to remove the qualifiers. */ 948 tp->t_const = tp->t_volatile = false; 949 tn = new_tnode(LOAD, tn->tn_sys, tp, tn, NULL); 950 } 951 952 return tn; 953 } 954 955 const tnode_t * 956 before_conversion(const tnode_t *tn) 957 { 958 while (tn->tn_op == CVT && !tn->tn_cast) 959 tn = tn->tn_left; 960 return tn; 961 } 962 963 static bool 964 is_null_pointer(const tnode_t *tn) 965 { 966 tspec_t t = tn->tn_type->t_tspec; 967 968 return ((t == PTR && tn->tn_type->t_subt->t_tspec == VOID) || 969 is_integer(t)) 970 && (tn->tn_op == CON && tn->tn_val->v_quad == 0); 971 } 972 973 /* 974 * Most errors required by ANSI C are reported in struct_or_union_member(). 975 * Here we only check for totally wrong things. 976 */ 977 static bool 978 typeok_point(const tnode_t *ln, const type_t *ltp, tspec_t lt) 979 { 980 if (is_struct_or_union(lt)) 981 return true; 982 983 if (lt == FUNC || lt == VOID || ltp->t_bitfield) 984 goto wrong; 985 986 /* 987 * Some C dialects from before C90 tolerated any lvalue on the 988 * left-hand side of the '.' operator, allowing things like 989 * char st[100]; st.st_mtime, assuming that the member 'st_mtime' 990 * only occurred in a single struct; see typeok_arrow. 991 */ 992 if (ln->tn_lvalue) 993 return true; 994 995 wrong: 996 /* With allow_c90 we already got an error */ 997 if (!allow_c90) 998 /* unacceptable operand of '%s' */ 999 error(111, op_name(POINT)); 1000 1001 return false; 1002 } 1003 1004 static bool 1005 typeok_arrow(tspec_t lt) 1006 { 1007 /* 1008 * C1978 Appendix A 14.1 says: <quote>In fact, any lvalue is allowed 1009 * before '.', and that lvalue is then assumed to have the form of 1010 * the structure of which the name of the right is a member. [...] 1011 * Such constructions are non-portable.</quote> 1012 */ 1013 if (lt == PTR || (!allow_c90 && is_integer(lt))) 1014 return true; 1015 1016 /* With allow_c90 we already got an error */ 1017 if (!allow_c90) 1018 /* unacceptable operand of '%s' */ 1019 error(111, op_name(ARROW)); 1020 return false; 1021 } 1022 1023 static bool 1024 typeok_incdec(op_t op, const tnode_t *tn, const type_t *tp) 1025 { 1026 /* operand has scalar type (checked in typeok) */ 1027 if (!tn->tn_lvalue) { 1028 if (tn->tn_op == CVT && tn->tn_cast && 1029 tn->tn_left->tn_op == LOAD) { 1030 /* a cast does not yield an lvalue */ 1031 error(163); 1032 } 1033 /* %soperand of '%s' must be lvalue */ 1034 error(114, "", op_name(op)); 1035 return false; 1036 } else if (tp->t_const) { 1037 if (allow_c90) 1038 /* %soperand of '%s' must be modifiable lvalue */ 1039 warning(115, "", op_name(op)); 1040 } 1041 return true; 1042 } 1043 1044 static bool 1045 typeok_address(const mod_t *mp, 1046 const tnode_t *tn, const type_t *tp, tspec_t t) 1047 { 1048 if (t == ARRAY || t == FUNC) { 1049 /* ok, a warning comes later (in build_address()) */ 1050 } else if (!tn->tn_lvalue) { 1051 if (tn->tn_op == CVT && tn->tn_cast && 1052 tn->tn_left->tn_op == LOAD) { 1053 /* a cast does not yield an lvalue */ 1054 error(163); 1055 } 1056 /* %soperand of '%s' must be lvalue */ 1057 error(114, "", mp->m_name); 1058 return false; 1059 } else if (is_scalar(t)) { 1060 if (tp->t_bitfield) { 1061 /* cannot take address of bit-field */ 1062 error(112); 1063 return false; 1064 } 1065 } else if (t != STRUCT && t != UNION) { 1066 /* unacceptable operand of '%s' */ 1067 error(111, mp->m_name); 1068 return false; 1069 } 1070 if (tn->tn_op == NAME && tn->tn_sym->s_register) { 1071 /* cannot take address of register '%s' */ 1072 error(113, tn->tn_sym->s_name); 1073 return false; 1074 } 1075 return true; 1076 } 1077 1078 static bool 1079 typeok_indir(const type_t *tp, tspec_t t) 1080 { 1081 1082 if (t != PTR) { 1083 /* cannot dereference non-pointer type '%s' */ 1084 error(96, type_name(tp)); 1085 return false; 1086 } 1087 return true; 1088 } 1089 1090 static bool 1091 typeok_plus(op_t op, 1092 const type_t *ltp, tspec_t lt, 1093 const type_t *rtp, tspec_t rt) 1094 { 1095 /* operands have scalar types (checked in typeok) */ 1096 if ((lt == PTR && !is_integer(rt)) || (rt == PTR && !is_integer(lt))) { 1097 warn_incompatible_types(op, ltp, lt, rtp, rt); 1098 return false; 1099 } 1100 return true; 1101 } 1102 1103 static bool 1104 typeok_minus(op_t op, 1105 const type_t *ltp, tspec_t lt, 1106 const type_t *rtp, tspec_t rt) 1107 { 1108 /* operands have scalar types (checked in typeok) */ 1109 if ((lt == PTR && rt != PTR && !is_integer(rt)) || 1110 (lt != PTR && rt == PTR)) { 1111 warn_incompatible_types(op, ltp, lt, rtp, rt); 1112 return false; 1113 } 1114 if (lt == PTR && rt == PTR) { 1115 if (!eqtype(ltp->t_subt, rtp->t_subt, true, false, NULL)) { 1116 /* illegal pointer subtraction */ 1117 error(116); 1118 } 1119 } 1120 return true; 1121 } 1122 1123 static void 1124 typeok_shr(const mod_t *mp, 1125 const tnode_t *ln, tspec_t lt, 1126 const tnode_t *rn, tspec_t rt) 1127 { 1128 tspec_t olt, ort; 1129 1130 olt = before_conversion(ln)->tn_type->t_tspec; 1131 ort = before_conversion(rn)->tn_type->t_tspec; 1132 1133 /* operands have integer types (checked in typeok) */ 1134 if (pflag && !is_uinteger(olt)) { 1135 /* 1136 * The left operand is signed. This means that 1137 * the operation is (possibly) nonportable. 1138 */ 1139 if (ln->tn_op != CON) { 1140 /* bitwise '%s' on signed value possibly nonportable */ 1141 warning(117, mp->m_name); 1142 } else if (ln->tn_val->v_quad < 0) { 1143 /* bitwise '%s' on signed value nonportable */ 1144 warning(120, mp->m_name); 1145 } 1146 } else if (allow_trad && allow_c90 && 1147 !is_uinteger(olt) && is_uinteger(ort)) { 1148 /* 1149 * The left operand would become unsigned in 1150 * traditional C. 1151 */ 1152 if (hflag && (ln->tn_op != CON || ln->tn_val->v_quad < 0)) { 1153 /* semantics of '%s' change in ANSI C; use ... */ 1154 warning(118, mp->m_name); 1155 } 1156 } else if (allow_trad && allow_c90 && 1157 !is_uinteger(olt) && !is_uinteger(ort) && 1158 portable_size_in_bits(lt) < portable_size_in_bits(rt)) { 1159 /* 1160 * In traditional C the left operand would be extended 1161 * (possibly sign-extended) and then shifted. 1162 */ 1163 if (hflag && (ln->tn_op != CON || ln->tn_val->v_quad < 0)) { 1164 /* semantics of '%s' change in ANSI C; use ... */ 1165 warning(118, mp->m_name); 1166 } 1167 } 1168 } 1169 1170 static void 1171 typeok_shl(const mod_t *mp, tspec_t lt, tspec_t rt) 1172 { 1173 /* 1174 * C90 does not perform balancing for shift operations, 1175 * but traditional C does. If the width of the right operand 1176 * is greater than the width of the left operand, then in 1177 * traditional C the left operand would be extended to the 1178 * width of the right operand. For SHL this may result in 1179 * different results. 1180 */ 1181 if (portable_size_in_bits(lt) < portable_size_in_bits(rt)) { 1182 /* 1183 * XXX If both operands are constant, make sure 1184 * that there is really a difference between 1185 * ANSI C and traditional C. 1186 */ 1187 if (hflag && !allow_c99) 1188 /* semantics of '%s' change in ANSI C; use ... */ 1189 warning(118, mp->m_name); 1190 } 1191 } 1192 1193 static void 1194 typeok_shift(tspec_t lt, const tnode_t *rn, tspec_t rt) 1195 { 1196 if (rn->tn_op != CON) 1197 return; 1198 1199 if (!is_uinteger(rt) && rn->tn_val->v_quad < 0) { 1200 /* negative shift */ 1201 warning(121); 1202 } else if ((uint64_t)rn->tn_val->v_quad == 1203 (uint64_t)size_in_bits(lt)) { 1204 /* shift equal to size of object */ 1205 warning(267); 1206 } else if ((uint64_t)rn->tn_val->v_quad > (uint64_t)size_in_bits(lt)) { 1207 /* shift amount %llu is greater than bit-size %llu of '%s' */ 1208 warning(122, (unsigned long long)rn->tn_val->v_quad, 1209 (unsigned long long)size_in_bits(lt), 1210 tspec_name(lt)); 1211 } 1212 } 1213 1214 static bool 1215 is_typeok_eq(const tnode_t *ln, tspec_t lt, const tnode_t *rn, tspec_t rt) 1216 { 1217 if (lt == PTR && is_null_pointer(rn)) 1218 return true; 1219 if (rt == PTR && is_null_pointer(ln)) 1220 return true; 1221 return false; 1222 } 1223 1224 static bool 1225 typeok_compare(op_t op, 1226 const tnode_t *ln, const type_t *ltp, tspec_t lt, 1227 const tnode_t *rn, const type_t *rtp, tspec_t rt) 1228 { 1229 const char *lx, *rx; 1230 1231 if (lt == PTR && rt == PTR) { 1232 check_pointer_comparison(op, ln, rn); 1233 return true; 1234 } 1235 1236 if (lt != PTR && rt != PTR) 1237 return true; 1238 1239 if (!is_integer(lt) && !is_integer(rt)) { 1240 warn_incompatible_types(op, ltp, lt, rtp, rt); 1241 return false; 1242 } 1243 1244 lx = lt == PTR ? "pointer" : "integer"; 1245 rx = rt == PTR ? "pointer" : "integer"; 1246 /* illegal combination of %s '%s' and %s '%s', op '%s' */ 1247 warning(123, lx, type_name(ltp), rx, type_name(rtp), op_name(op)); 1248 return true; 1249 } 1250 1251 static bool 1252 typeok_quest(tspec_t lt, const tnode_t *rn) 1253 { 1254 if (!is_scalar(lt)) { 1255 /* first operand must have scalar type, op ? : */ 1256 error(170); 1257 return false; 1258 } 1259 lint_assert(before_conversion(rn)->tn_op == COLON); 1260 return true; 1261 } 1262 1263 static void 1264 typeok_colon_pointer(const mod_t *mp, const type_t *ltp, const type_t *rtp) 1265 { 1266 type_t *lstp = ltp->t_subt; 1267 type_t *rstp = rtp->t_subt; 1268 tspec_t lst = lstp->t_tspec; 1269 tspec_t rst = rstp->t_tspec; 1270 1271 if ((lst == VOID && rst == FUNC) || (lst == FUNC && rst == VOID)) { 1272 /* (void *)0 is handled in typeok_colon */ 1273 /* TODO: C99 behaves like C90 here. */ 1274 if (!allow_trad && !allow_c99) 1275 /* ANSI C forbids conversion of %s to %s, op %s */ 1276 warning(305, "function pointer", "'void *'", 1277 mp->m_name); 1278 return; 1279 } 1280 1281 if (eqptrtype(lstp, rstp, true)) 1282 return; 1283 if (!eqtype(lstp, rstp, true, false, NULL)) 1284 warn_incompatible_pointers(mp, ltp, rtp); 1285 } 1286 1287 static bool 1288 typeok_colon(const mod_t *mp, 1289 const tnode_t *ln, const type_t *ltp, tspec_t lt, 1290 const tnode_t *rn, const type_t *rtp, tspec_t rt) 1291 { 1292 1293 if (is_arithmetic(lt) && is_arithmetic(rt)) 1294 return true; 1295 if (lt == BOOL && rt == BOOL) 1296 return true; 1297 1298 if (lt == STRUCT && rt == STRUCT && ltp->t_str == rtp->t_str) 1299 return true; 1300 if (lt == UNION && rt == UNION && ltp->t_str == rtp->t_str) 1301 return true; 1302 1303 if (lt == PTR && is_null_pointer(rn)) 1304 return true; 1305 if (rt == PTR && is_null_pointer(ln)) 1306 return true; 1307 1308 if ((lt == PTR && is_integer(rt)) || (is_integer(lt) && rt == PTR)) { 1309 const char *lx = lt == PTR ? "pointer" : "integer"; 1310 const char *rx = rt == PTR ? "pointer" : "integer"; 1311 /* illegal combination of %s '%s' and %s '%s', op '%s' */ 1312 warning(123, lx, type_name(ltp), 1313 rx, type_name(rtp), mp->m_name); 1314 return true; 1315 } 1316 1317 if (lt == VOID || rt == VOID) { 1318 if (lt != VOID || rt != VOID) 1319 /* incompatible types '%s' and '%s' in conditional */ 1320 warning(126, type_name(ltp), type_name(rtp)); 1321 return true; 1322 } 1323 1324 if (lt == PTR && rt == PTR) { 1325 typeok_colon_pointer(mp, ltp, rtp); 1326 return true; 1327 } 1328 1329 /* incompatible types '%s' and '%s' in conditional */ 1330 error(126, type_name(ltp), type_name(rtp)); 1331 return false; 1332 } 1333 1334 static bool 1335 typeok_assign(op_t op, const tnode_t *ln, const type_t *ltp, tspec_t lt) 1336 { 1337 if (op == RETURN || op == INIT || op == FARG) 1338 return true; 1339 1340 if (!ln->tn_lvalue) { 1341 if (ln->tn_op == CVT && ln->tn_cast && 1342 ln->tn_left->tn_op == LOAD) { 1343 /* a cast does not yield an lvalue */ 1344 error(163); 1345 } 1346 /* %soperand of '%s' must be lvalue */ 1347 error(114, "left ", op_name(op)); 1348 return false; 1349 } else if (ltp->t_const || (is_struct_or_union(lt) && 1350 has_constant_member(ltp))) { 1351 if (allow_c90) 1352 /* %soperand of '%s' must be modifiable lvalue */ 1353 warning(115, "left ", op_name(op)); 1354 } 1355 return true; 1356 } 1357 1358 /* Check the types using the information from modtab[]. */ 1359 static bool 1360 typeok_scalar(op_t op, const mod_t *mp, 1361 const type_t *ltp, tspec_t lt, 1362 const type_t *rtp, tspec_t rt) 1363 { 1364 if (mp->m_takes_bool && lt == BOOL && rt == BOOL) 1365 return true; 1366 if (mp->m_requires_integer) { 1367 if (!is_integer(lt) || (mp->m_binary && !is_integer(rt))) { 1368 warn_incompatible_types(op, ltp, lt, rtp, rt); 1369 return false; 1370 } 1371 } else if (mp->m_requires_integer_or_complex) { 1372 if ((!is_integer(lt) && !is_complex(lt)) || 1373 (mp->m_binary && (!is_integer(rt) && !is_complex(rt)))) { 1374 warn_incompatible_types(op, ltp, lt, rtp, rt); 1375 return false; 1376 } 1377 } else if (mp->m_requires_scalar) { 1378 if (!is_scalar(lt) || (mp->m_binary && !is_scalar(rt))) { 1379 warn_incompatible_types(op, ltp, lt, rtp, rt); 1380 return false; 1381 } 1382 } else if (mp->m_requires_arith) { 1383 if (!is_arithmetic(lt) || 1384 (mp->m_binary && !is_arithmetic(rt))) { 1385 warn_incompatible_types(op, ltp, lt, rtp, rt); 1386 return false; 1387 } 1388 } 1389 return true; 1390 } 1391 1392 /* 1393 * Check the types for specific operators and type combinations. 1394 * 1395 * At this point, the operands already conform to the type requirements of 1396 * the operator, such as being integer, floating or scalar. 1397 */ 1398 static bool 1399 typeok_op(op_t op, const mod_t *mp, int arg, 1400 const tnode_t *ln, const type_t *ltp, tspec_t lt, 1401 const tnode_t *rn, const type_t *rtp, tspec_t rt) 1402 { 1403 switch (op) { 1404 case ARROW: 1405 return typeok_arrow(lt); 1406 case POINT: 1407 return typeok_point(ln, ltp, lt); 1408 case INCBEF: 1409 case DECBEF: 1410 case INCAFT: 1411 case DECAFT: 1412 return typeok_incdec(op, ln, ltp); 1413 case INDIR: 1414 return typeok_indir(ltp, lt); 1415 case ADDR: 1416 return typeok_address(mp, ln, ltp, lt); 1417 case PLUS: 1418 return typeok_plus(op, ltp, lt, rtp, rt); 1419 case MINUS: 1420 return typeok_minus(op, ltp, lt, rtp, rt); 1421 case SHL: 1422 typeok_shl(mp, lt, rt); 1423 goto shift; 1424 case SHR: 1425 typeok_shr(mp, ln, lt, rn, rt); 1426 shift: 1427 typeok_shift(lt, rn, rt); 1428 break; 1429 case LT: 1430 case LE: 1431 case GT: 1432 case GE: 1433 compare: 1434 return typeok_compare(op, ln, ltp, lt, rn, rtp, rt); 1435 case EQ: 1436 case NE: 1437 if (is_typeok_eq(ln, lt, rn, rt)) 1438 break; 1439 goto compare; 1440 case QUEST: 1441 return typeok_quest(lt, rn); 1442 case COLON: 1443 return typeok_colon(mp, ln, ltp, lt, rn, rtp, rt); 1444 case ASSIGN: 1445 case INIT: 1446 case FARG: 1447 case RETURN: 1448 if (!check_assign_types_compatible(op, arg, ln, rn)) 1449 return false; 1450 goto assign; 1451 case MULASS: 1452 case DIVASS: 1453 case MODASS: 1454 goto assign; 1455 case ADDASS: 1456 case SUBASS: 1457 if ((lt == PTR && !is_integer(rt)) || rt == PTR) { 1458 warn_incompatible_types(op, ltp, lt, rtp, rt); 1459 return false; 1460 } 1461 goto assign; 1462 case SHLASS: 1463 goto assign; 1464 case SHRASS: 1465 if (pflag && !is_uinteger(lt) && 1466 !(!allow_c90 && is_uinteger(rt))) { 1467 /* bitwise '%s' on signed value possibly nonportable */ 1468 warning(117, mp->m_name); 1469 } 1470 goto assign; 1471 case ANDASS: 1472 case XORASS: 1473 case ORASS: 1474 assign: 1475 return typeok_assign(op, ln, ltp, lt); 1476 case COMMA: 1477 if (!modtab[ln->tn_op].m_has_side_effect) 1478 check_null_effect(ln); 1479 break; 1480 default: 1481 break; 1482 } 1483 return true; 1484 } 1485 1486 static void 1487 typeok_enum(op_t op, const mod_t *mp, int arg, 1488 const tnode_t *ln, const type_t *ltp, 1489 const tnode_t *rn, const type_t *rtp) 1490 { 1491 if (mp->m_bad_on_enum && 1492 (ltp->t_is_enum || (mp->m_binary && rtp->t_is_enum))) { 1493 check_bad_enum_operation(op, ln, rn); 1494 } else if (mp->m_valid_on_enum && 1495 (ltp->t_is_enum && rtp != NULL && rtp->t_is_enum)) { 1496 check_enum_type_mismatch(op, arg, ln, rn); 1497 } else if (mp->m_valid_on_enum && 1498 (ltp->t_is_enum || (rtp != NULL && rtp->t_is_enum))) { 1499 check_enum_int_mismatch(op, arg, ln, rn); 1500 } 1501 } 1502 1503 /* Perform most type checks. Return whether the types are ok. */ 1504 bool 1505 typeok(op_t op, int arg, const tnode_t *ln, const tnode_t *rn) 1506 { 1507 const mod_t *mp; 1508 tspec_t lt, rt; 1509 type_t *ltp, *rtp; 1510 1511 mp = &modtab[op]; 1512 1513 lint_assert((ltp = ln->tn_type) != NULL); 1514 lt = ltp->t_tspec; 1515 1516 if (mp->m_binary) { 1517 lint_assert((rtp = rn->tn_type) != NULL); 1518 rt = rtp->t_tspec; 1519 } else { 1520 rtp = NULL; 1521 rt = NOTSPEC; 1522 } 1523 1524 if (Tflag && !typeok_scalar_strict_bool(op, mp, arg, ln, rn)) 1525 return false; 1526 if (!typeok_scalar(op, mp, ltp, lt, rtp, rt)) 1527 return false; 1528 1529 if (!typeok_op(op, mp, arg, ln, ltp, lt, rn, rtp, rt)) 1530 return false; 1531 1532 typeok_enum(op, mp, arg, ln, ltp, rn, rtp); 1533 return true; 1534 } 1535 1536 static void 1537 check_pointer_comparison(op_t op, const tnode_t *ln, const tnode_t *rn) 1538 { 1539 type_t *ltp, *rtp; 1540 tspec_t lst, rst; 1541 const char *lsts, *rsts; 1542 1543 lst = (ltp = ln->tn_type)->t_subt->t_tspec; 1544 rst = (rtp = rn->tn_type)->t_subt->t_tspec; 1545 1546 if (lst == VOID || rst == VOID) { 1547 /* TODO: C99 behaves like C90 here. */ 1548 if ((!allow_trad && !allow_c99) && 1549 (lst == FUNC || rst == FUNC)) { 1550 /* (void *)0 already handled in typeok() */ 1551 *(lst == FUNC ? &lsts : &rsts) = "function pointer"; 1552 *(lst == VOID ? &lsts : &rsts) = "'void *'"; 1553 /* ANSI C forbids comparison of %s with %s */ 1554 warning(274, lsts, rsts); 1555 } 1556 return; 1557 } 1558 1559 if (!eqtype(ltp->t_subt, rtp->t_subt, true, false, NULL)) { 1560 warn_incompatible_pointers(&modtab[op], ltp, rtp); 1561 return; 1562 } 1563 1564 if (lst == FUNC && rst == FUNC) { 1565 /* TODO: C99 behaves like C90 here, see C99 6.5.8p2. */ 1566 if ((!allow_trad && !allow_c99) && op != EQ && op != NE) 1567 /* ANSI C forbids ordered comparisons of ... */ 1568 warning(125); 1569 } 1570 } 1571 1572 static bool 1573 is_direct_function_call(const tnode_t *tn, const char **out_name) 1574 { 1575 1576 if (!(tn->tn_op == CALL && 1577 tn->tn_left->tn_op == ADDR && 1578 tn->tn_left->tn_left->tn_op == NAME)) 1579 return false; 1580 1581 *out_name = tn->tn_left->tn_left->tn_sym->s_name; 1582 return true; 1583 } 1584 1585 static bool 1586 is_unconst_function(const char *name) 1587 { 1588 1589 return strcmp(name, "memchr") == 0 || 1590 strcmp(name, "strchr") == 0 || 1591 strcmp(name, "strpbrk") == 0 || 1592 strcmp(name, "strrchr") == 0 || 1593 strcmp(name, "strstr") == 0; 1594 } 1595 1596 static bool 1597 is_const_char_pointer(const tnode_t *tn) 1598 { 1599 const type_t *tp; 1600 1601 /* 1602 * For traditional reasons, C99 6.4.5p5 defines that string literals 1603 * have type 'char[]'. They are often implicitly converted to 1604 * 'char *', for example when they are passed as function arguments. 1605 * 1606 * C99 6.4.5p6 further defines that modifying a string that is 1607 * constructed from a string literal invokes undefined behavior. 1608 * 1609 * Out of these reasons, string literals are treated as 'effectively 1610 * const' here. 1611 */ 1612 if (tn->tn_op == CVT && 1613 tn->tn_left->tn_op == ADDR && 1614 tn->tn_left->tn_left->tn_op == STRING) 1615 return true; 1616 1617 tp = before_conversion(tn)->tn_type; 1618 return tp->t_tspec == PTR && 1619 tp->t_subt->t_tspec == CHAR && 1620 tp->t_subt->t_const; 1621 } 1622 1623 static bool 1624 is_const_pointer(const tnode_t *tn) 1625 { 1626 const type_t *tp; 1627 1628 tp = before_conversion(tn)->tn_type; 1629 return tp->t_tspec == PTR && tp->t_subt->t_const; 1630 } 1631 1632 static bool 1633 is_first_arg_const_char_pointer(const tnode_t *tn) 1634 { 1635 const tnode_t *an; 1636 1637 an = tn->tn_right; 1638 if (an == NULL) 1639 return false; 1640 1641 while (an->tn_right != NULL) 1642 an = an->tn_right; 1643 return is_const_char_pointer(an->tn_left); 1644 } 1645 1646 static bool 1647 is_second_arg_const_pointer(const tnode_t *tn) 1648 { 1649 const tnode_t *an; 1650 1651 an = tn->tn_right; 1652 if (an == NULL || an->tn_right == NULL) 1653 return false; 1654 1655 while (an->tn_right->tn_right != NULL) 1656 an = an->tn_right; 1657 return is_const_pointer(an->tn_left); 1658 } 1659 1660 static void 1661 check_unconst_function(const type_t *lstp, const tnode_t *rn) 1662 { 1663 const char *function_name; 1664 1665 if (lstp->t_tspec == CHAR && !lstp->t_const && 1666 is_direct_function_call(rn, &function_name) && 1667 is_unconst_function(function_name) && 1668 is_first_arg_const_char_pointer(rn)) { 1669 /* call to '%s' effectively discards 'const' from argument */ 1670 warning(346, function_name); 1671 } 1672 1673 if (!lstp->t_const && 1674 is_direct_function_call(rn, &function_name) && 1675 strcmp(function_name, "bsearch") == 0 && 1676 is_second_arg_const_pointer(rn)) { 1677 /* call to '%s' effectively discards 'const' from argument */ 1678 warning(346, function_name); 1679 } 1680 } 1681 1682 static void 1683 check_assign_void_pointer(op_t op, int arg, 1684 tspec_t lt, tspec_t lst, 1685 tspec_t rt, tspec_t rst) 1686 { 1687 const char *lts, *rts; 1688 1689 if (!(lt == PTR && rt == PTR && (lst == VOID || rst == VOID))) 1690 return; 1691 /* two pointers, at least one pointer to void */ 1692 1693 /* TODO: C99 behaves like C90 here. */ 1694 if (!((!allow_trad && !allow_c99) && (lst == FUNC || rst == FUNC))) 1695 return; 1696 /* comb. of ptr to func and ptr to void */ 1697 1698 *(lst == FUNC ? <s : &rts) = "function pointer"; 1699 *(lst == VOID ? <s : &rts) = "'void *'"; 1700 1701 switch (op) { 1702 case INIT: 1703 case RETURN: 1704 /* ANSI C forbids conversion of %s to %s */ 1705 warning(303, rts, lts); 1706 break; 1707 case FARG: 1708 /* ANSI C forbids conversion of %s to %s, arg #%d */ 1709 warning(304, rts, lts, arg); 1710 break; 1711 default: 1712 /* ANSI C forbids conversion of %s to %s, op %s */ 1713 warning(305, rts, lts, op_name(op)); 1714 break; 1715 } 1716 } 1717 1718 static bool 1719 check_assign_void_pointer_compat(op_t op, int arg, 1720 const type_t *const ltp, tspec_t const lt, 1721 const type_t *const lstp, tspec_t const lst, 1722 const tnode_t *const rn, 1723 const type_t *const rtp, tspec_t const rt, 1724 const type_t *const rstp, tspec_t const rst) 1725 { 1726 if (!(lt == PTR && rt == PTR && (lst == VOID || rst == VOID || 1727 eqtype(lstp, rstp, true, false, NULL)))) 1728 return false; 1729 1730 /* compatible pointer types (qualifiers ignored) */ 1731 if (allow_c90 && 1732 ((!lstp->t_const && rstp->t_const) || 1733 (!lstp->t_volatile && rstp->t_volatile))) { 1734 /* left side has not all qualifiers of right */ 1735 switch (op) { 1736 case INIT: 1737 case RETURN: 1738 /* incompatible pointer types to '%s' and '%s' */ 1739 warning(182, type_name(lstp), type_name(rstp)); 1740 break; 1741 case FARG: 1742 /* converting '%s' to incompatible '%s' ... */ 1743 warning(153, 1744 type_name(rtp), type_name(ltp), arg); 1745 break; 1746 default: 1747 /* operands of '%s' have incompatible pointer ... */ 1748 warning(128, op_name(op), 1749 type_name(lstp), type_name(rstp)); 1750 break; 1751 } 1752 } 1753 1754 if (allow_c90) 1755 check_unconst_function(lstp, rn); 1756 1757 return true; 1758 } 1759 1760 static bool 1761 check_assign_pointer_integer(op_t op, int arg, 1762 const type_t *const ltp, tspec_t const lt, 1763 const type_t *const rtp, tspec_t const rt) 1764 { 1765 const char *lx, *rx; 1766 1767 if (!((lt == PTR && is_integer(rt)) || (is_integer(lt) && rt == PTR))) 1768 return false; 1769 1770 lx = lt == PTR ? "pointer" : "integer"; 1771 rx = rt == PTR ? "pointer" : "integer"; 1772 1773 switch (op) { 1774 case INIT: 1775 case RETURN: 1776 /* illegal combination of %s '%s' and %s '%s' */ 1777 warning(183, lx, type_name(ltp), rx, type_name(rtp)); 1778 break; 1779 case FARG: 1780 /* illegal combination of %s '%s' and %s '%s', arg #%d */ 1781 warning(154, 1782 lx, type_name(ltp), rx, type_name(rtp), arg); 1783 break; 1784 default: 1785 /* illegal combination of %s '%s' and %s '%s', op '%s' */ 1786 warning(123, 1787 lx, type_name(ltp), rx, type_name(rtp), op_name(op)); 1788 break; 1789 } 1790 return true; 1791 } 1792 1793 static bool 1794 check_assign_pointer(op_t op, int arg, 1795 const type_t *ltp, tspec_t lt, 1796 const type_t *rtp, tspec_t rt) 1797 { 1798 if (!(lt == PTR && rt == PTR)) 1799 return false; 1800 1801 switch (op) { 1802 case RETURN: 1803 warn_incompatible_pointers(NULL, ltp, rtp); 1804 break; 1805 case FARG: 1806 /* converting '%s' to incompatible '%s' for ... */ 1807 warning(153, type_name(rtp), type_name(ltp), arg); 1808 break; 1809 default: 1810 warn_incompatible_pointers(&modtab[op], ltp, rtp); 1811 break; 1812 } 1813 return true; 1814 } 1815 1816 static void 1817 warn_assign(op_t op, int arg, 1818 const type_t *ltp, tspec_t lt, 1819 const type_t *rtp, tspec_t rt) 1820 { 1821 switch (op) { 1822 case INIT: 1823 /* cannot initialize '%s' from '%s' */ 1824 error(185, type_name(ltp), type_name(rtp)); 1825 break; 1826 case RETURN: 1827 /* function has return type '%s' but returns '%s' */ 1828 error(211, type_name(ltp), type_name(rtp)); 1829 break; 1830 case FARG: 1831 /* passing '%s' to incompatible '%s', arg #%d */ 1832 warning(155, type_name(rtp), type_name(ltp), arg); 1833 break; 1834 default: 1835 warn_incompatible_types(op, ltp, lt, rtp, rt); 1836 break; 1837 } 1838 } 1839 1840 /* 1841 * Checks type compatibility for ASSIGN, INIT, FARG and RETURN 1842 * and prints warnings/errors if necessary. 1843 * Returns whether the types are (almost) compatible. 1844 */ 1845 static bool 1846 check_assign_types_compatible(op_t op, int arg, 1847 const tnode_t *ln, const tnode_t *rn) 1848 { 1849 tspec_t lt, rt, lst = NOTSPEC, rst = NOTSPEC; 1850 type_t *ltp, *rtp, *lstp = NULL, *rstp = NULL; 1851 1852 if ((lt = (ltp = ln->tn_type)->t_tspec) == PTR) 1853 lst = (lstp = ltp->t_subt)->t_tspec; 1854 if ((rt = (rtp = rn->tn_type)->t_tspec) == PTR) 1855 rst = (rstp = rtp->t_subt)->t_tspec; 1856 1857 if (lt == BOOL && is_scalar(rt)) /* C99 6.3.1.2 */ 1858 return true; 1859 1860 if (is_arithmetic(lt) && (is_arithmetic(rt) || rt == BOOL)) 1861 return true; 1862 1863 if (is_struct_or_union(lt) && is_struct_or_union(rt)) 1864 /* both are struct or union */ 1865 return ltp->t_str == rtp->t_str; 1866 1867 /* a null pointer may be assigned to any pointer */ 1868 if (lt == PTR && is_null_pointer(rn)) 1869 return true; 1870 1871 check_assign_void_pointer(op, arg, lt, lst, rt, rst); 1872 1873 if (check_assign_void_pointer_compat(op, arg, 1874 ltp, lt, lstp, lst, rn, rtp, rt, rstp, rst)) 1875 return true; 1876 1877 if (check_assign_pointer_integer(op, arg, ltp, lt, rtp, rt)) 1878 return true; 1879 1880 if (check_assign_pointer(op, arg, ltp, lt, rtp, rt)) 1881 return true; 1882 1883 warn_assign(op, arg, ltp, lt, rtp, rt); 1884 return false; 1885 } 1886 1887 /* Prints a warning if a strange operator is used on an enum type. */ 1888 static void 1889 check_bad_enum_operation(op_t op, const tnode_t *ln, const tnode_t *rn) 1890 { 1891 1892 if (!eflag) 1893 return; 1894 1895 /* 1896 * Enum as offset to a pointer is an exception (otherwise enums 1897 * could not be used as array indices). 1898 */ 1899 if (op == PLUS && 1900 ((ln->tn_type->t_is_enum && rn->tn_type->t_tspec == PTR) || 1901 (rn->tn_type->t_is_enum && ln->tn_type->t_tspec == PTR))) { 1902 return; 1903 } 1904 1905 /* dubious operation on enum, op '%s' */ 1906 warning(241, op_name(op)); 1907 } 1908 1909 /* 1910 * Prints a warning if an operator is applied to two different enum types. 1911 */ 1912 static void 1913 check_enum_type_mismatch(op_t op, int arg, const tnode_t *ln, const tnode_t *rn) 1914 { 1915 const mod_t *mp; 1916 1917 mp = &modtab[op]; 1918 1919 if (ln->tn_type->t_enum != rn->tn_type->t_enum) { 1920 switch (op) { 1921 case INIT: 1922 /* enum type mismatch between '%s' and '%s' in ... */ 1923 warning(210, 1924 type_name(ln->tn_type), type_name(rn->tn_type)); 1925 break; 1926 case FARG: 1927 /* function expects '%s', passing '%s' for arg #%d */ 1928 warning(156, 1929 type_name(ln->tn_type), type_name(rn->tn_type), 1930 arg); 1931 break; 1932 case RETURN: 1933 /* function has return type '%s' but returns '%s' */ 1934 warning(211, 1935 type_name(ln->tn_type), type_name(rn->tn_type)); 1936 break; 1937 default: 1938 /* enum type mismatch: '%s' '%s' '%s' */ 1939 warning(130, type_name(ln->tn_type), mp->m_name, 1940 type_name(rn->tn_type)); 1941 break; 1942 } 1943 } else if (Pflag && mp->m_comparison && op != EQ && op != NE) { 1944 if (eflag) 1945 /* dubious comparison of enums, op '%s' */ 1946 warning(243, mp->m_name); 1947 } 1948 } 1949 1950 /* Prints a warning if the operands mix between enum and integer. */ 1951 static void 1952 check_enum_int_mismatch(op_t op, int arg, const tnode_t *ln, const tnode_t *rn) 1953 { 1954 1955 if (!eflag) 1956 return; 1957 1958 switch (op) { 1959 case INIT: 1960 /* 1961 * Initialization with 0 is allowed. Otherwise, all implicit 1962 * initializations would need to be warned upon as well. 1963 */ 1964 if (!rn->tn_type->t_is_enum && rn->tn_op == CON && 1965 is_integer(rn->tn_type->t_tspec) && 1966 rn->tn_val->v_quad == 0) { 1967 return; 1968 } 1969 /* initialization of '%s' with '%s' */ 1970 warning(277, type_name(ln->tn_type), type_name(rn->tn_type)); 1971 break; 1972 case FARG: 1973 /* combination of '%s' and '%s', arg #%d */ 1974 warning(278, 1975 type_name(ln->tn_type), type_name(rn->tn_type), arg); 1976 break; 1977 case RETURN: 1978 /* combination of '%s' and '%s' in return */ 1979 warning(279, type_name(ln->tn_type), type_name(rn->tn_type)); 1980 break; 1981 default: 1982 /* combination of '%s' and '%s', op '%s' */ 1983 warning(242, type_name(ln->tn_type), type_name(rn->tn_type), 1984 op_name(op)); 1985 break; 1986 } 1987 } 1988 1989 static void 1990 check_enum_array_index(const tnode_t *ln, const tnode_t *rn) 1991 { 1992 int max_array_index; 1993 int64_t max_enum_value; 1994 const struct sym *ec, *max_ec; 1995 const type_t *lt, *rt; 1996 1997 if (ln->tn_op != ADDR || ln->tn_left->tn_op != NAME) 1998 return; 1999 2000 lt = ln->tn_left->tn_type; 2001 if (lt->t_tspec != ARRAY || lt->t_incomplete_array) 2002 return; 2003 2004 if (rn->tn_op != CVT || !rn->tn_type->t_is_enum) 2005 return; 2006 if (rn->tn_left->tn_op != LOAD) 2007 return; 2008 2009 rt = rn->tn_left->tn_type; 2010 ec = rt->t_enum->en_first_enumerator; 2011 max_ec = ec; 2012 lint_assert(ec != NULL); 2013 for (ec = ec->s_next; ec != NULL; ec = ec->s_next) 2014 if (ec->u.s_enum_constant > max_ec->u.s_enum_constant) 2015 max_ec = ec; 2016 2017 max_enum_value = max_ec->u.s_enum_constant; 2018 lint_assert(INT_MIN <= max_enum_value && max_enum_value <= INT_MAX); 2019 2020 max_array_index = lt->t_dim - 1; 2021 if (max_enum_value == max_array_index) 2022 return; 2023 2024 /* 2025 * If the largest enum constant is named '*_NUM_*', it is typically 2026 * not part of the allowed enum values but a marker for the number 2027 * of actual enum values. 2028 */ 2029 if (max_enum_value == max_array_index + 1 && 2030 (strstr(max_ec->s_name, "NUM") != NULL || 2031 strstr(max_ec->s_name, "num") != NULL)) 2032 return; 2033 2034 /* maximum value %d of '%s' does not match maximum array index %d */ 2035 warning(348, (int)max_enum_value, type_name(rt), max_array_index); 2036 print_previous_declaration(-1, max_ec); 2037 } 2038 2039 /* 2040 * Build and initialize a new node. 2041 */ 2042 static tnode_t * 2043 new_tnode(op_t op, bool sys, type_t *type, tnode_t *ln, tnode_t *rn) 2044 { 2045 tnode_t *ntn; 2046 tspec_t t; 2047 #if 0 /* not yet */ 2048 size_t l; 2049 uint64_t rnum; 2050 #endif 2051 2052 ntn = expr_alloc_tnode(); 2053 2054 ntn->tn_op = op; 2055 ntn->tn_type = type; 2056 ntn->tn_sys = sys; 2057 ntn->tn_left = ln; 2058 ntn->tn_right = rn; 2059 2060 switch (op) { 2061 #if 0 /* not yet */ 2062 case SHR: 2063 if (rn->tn_op != CON) 2064 break; 2065 rnum = rn->tn_val->v_quad; 2066 l = type_size_in_bits(ln->tn_type) / CHAR_SIZE; 2067 t = ln->tn_type->t_tspec; 2068 switch (l) { 2069 case 8: 2070 if (rnum >= 56) 2071 t = UCHAR; 2072 else if (rnum >= 48) 2073 t = USHORT; 2074 else if (rnum >= 32) 2075 t = UINT; 2076 break; 2077 case 4: 2078 if (rnum >= 24) 2079 t = UCHAR; 2080 else if (rnum >= 16) 2081 t = USHORT; 2082 break; 2083 case 2: 2084 if (rnum >= 8) 2085 t = UCHAR; 2086 break; 2087 default: 2088 break; 2089 } 2090 if (t != ln->tn_type->t_tspec) 2091 ntn->tn_type->t_tspec = t; 2092 break; 2093 #endif 2094 case INDIR: 2095 case FSEL: 2096 lint_assert(ln->tn_type->t_tspec == PTR); 2097 t = ln->tn_type->t_subt->t_tspec; 2098 if (t != FUNC && t != VOID) 2099 ntn->tn_lvalue = true; 2100 break; 2101 default: 2102 break; 2103 } 2104 2105 return ntn; 2106 } 2107 2108 /* 2109 * Performs the "integer promotions" (C99 6.3.1.1p2), which convert small 2110 * integer types to either int or unsigned int. 2111 * 2112 * If allow_c90 is unset or the operand is a function argument with no type 2113 * information (no prototype or variable # of args), converts float to double. 2114 */ 2115 tnode_t * 2116 promote(op_t op, bool farg, tnode_t *tn) 2117 { 2118 tspec_t t; 2119 type_t *ntp; 2120 unsigned int len; 2121 2122 t = tn->tn_type->t_tspec; 2123 2124 if (!is_arithmetic(t)) 2125 return tn; 2126 2127 if (allow_c90) { 2128 /* 2129 * C99 6.3.1.1p2 requires for types with lower rank than int 2130 * that "If an int can represent all the values of the 2131 * original type, the value is converted to an int; otherwise 2132 * it is converted to an unsigned int", and that "All other 2133 * types are unchanged by the integer promotions". 2134 */ 2135 if (tn->tn_type->t_bitfield) { 2136 len = tn->tn_type->t_flen; 2137 if (len < size_in_bits(INT)) { 2138 t = INT; 2139 } else if (len == size_in_bits(INT)) { 2140 t = is_uinteger(t) ? UINT : INT; 2141 } 2142 } else if (t == CHAR || t == UCHAR || t == SCHAR) { 2143 t = (size_in_bits(CHAR) < size_in_bits(INT) 2144 || t != UCHAR) ? INT : UINT; 2145 } else if (t == SHORT || t == USHORT) { 2146 t = (size_in_bits(SHORT) < size_in_bits(INT) 2147 || t == SHORT) ? INT : UINT; 2148 } else if (t == ENUM) { 2149 t = INT; 2150 } else if (farg && t == FLOAT) { 2151 t = DOUBLE; 2152 } 2153 } else { 2154 /* 2155 * In traditional C, keep unsigned and promote FLOAT 2156 * to DOUBLE. 2157 */ 2158 if (t == UCHAR || t == USHORT) { 2159 t = UINT; 2160 } else if (t == CHAR || t == SCHAR || t == SHORT) { 2161 t = INT; 2162 } else if (t == FLOAT) { 2163 t = DOUBLE; 2164 } else if (t == ENUM) { 2165 t = INT; 2166 } 2167 } 2168 2169 if (t != tn->tn_type->t_tspec) { 2170 ntp = expr_dup_type(tn->tn_type); 2171 ntp->t_tspec = t; 2172 /* 2173 * Keep t_is_enum even though t_tspec gets converted from 2174 * ENUM to INT, so we are later able to check compatibility 2175 * of enum types. 2176 */ 2177 tn = convert(op, 0, ntp, tn); 2178 } 2179 2180 return tn; 2181 } 2182 2183 /* 2184 * Apply the "usual arithmetic conversions" (C99 6.3.1.8). 2185 * 2186 * This gives both operands the same type. 2187 * This is done in different ways for traditional C and C90. 2188 */ 2189 static void 2190 balance(op_t op, tnode_t **lnp, tnode_t **rnp) 2191 { 2192 tspec_t lt, rt, t; 2193 int i; 2194 bool u; 2195 type_t *ntp; 2196 static const tspec_t tl[] = { 2197 LDOUBLE, DOUBLE, FLOAT, 2198 #ifdef INT128_SIZE 2199 UINT128, INT128, 2200 #endif 2201 UQUAD, QUAD, 2202 ULONG, LONG, 2203 UINT, INT, 2204 }; 2205 2206 lt = (*lnp)->tn_type->t_tspec; 2207 rt = (*rnp)->tn_type->t_tspec; 2208 2209 if (!is_arithmetic(lt) || !is_arithmetic(rt)) 2210 return; 2211 2212 if (allow_c90) { 2213 if (lt == rt) { 2214 t = lt; 2215 } else if (lt == LCOMPLEX || rt == LCOMPLEX) { 2216 t = LCOMPLEX; 2217 } else if (lt == DCOMPLEX || rt == DCOMPLEX) { 2218 t = DCOMPLEX; 2219 } else if (lt == FCOMPLEX || rt == FCOMPLEX) { 2220 t = FCOMPLEX; 2221 } else if (lt == LDOUBLE || rt == LDOUBLE) { 2222 t = LDOUBLE; 2223 } else if (lt == DOUBLE || rt == DOUBLE) { 2224 t = DOUBLE; 2225 } else if (lt == FLOAT || rt == FLOAT) { 2226 t = FLOAT; 2227 } else { 2228 /* 2229 * If type A has more bits than type B it should 2230 * be able to hold all possible values of type B. 2231 */ 2232 if (size_in_bits(lt) > size_in_bits(rt)) { 2233 t = lt; 2234 } else if (size_in_bits(lt) < size_in_bits(rt)) { 2235 t = rt; 2236 } else { 2237 for (i = 3; tl[i] != INT; i++) { 2238 if (tl[i] == lt || tl[i] == rt) 2239 break; 2240 } 2241 if ((is_uinteger(lt) || is_uinteger(rt)) && 2242 !is_uinteger(tl[i])) { 2243 i--; 2244 } 2245 t = tl[i]; 2246 } 2247 } 2248 } else { 2249 /* Keep unsigned in traditional C */ 2250 u = is_uinteger(lt) || is_uinteger(rt); 2251 for (i = 0; tl[i] != INT; i++) { 2252 if (lt == tl[i] || rt == tl[i]) 2253 break; 2254 } 2255 t = tl[i]; 2256 if (u && is_integer(t) && !is_uinteger(t)) 2257 t = unsigned_type(t); 2258 } 2259 2260 if (t != lt) { 2261 ntp = expr_dup_type((*lnp)->tn_type); 2262 ntp->t_tspec = t; 2263 *lnp = convert(op, 0, ntp, *lnp); 2264 } 2265 if (t != rt) { 2266 ntp = expr_dup_type((*rnp)->tn_type); 2267 ntp->t_tspec = t; 2268 *rnp = convert(op, 0, ntp, *rnp); 2269 } 2270 } 2271 2272 /* 2273 * Insert a conversion operator, which converts the type of the node 2274 * to another given type. 2275 * If op is FARG, arg is the number of the argument (used for warnings). 2276 */ 2277 tnode_t * 2278 convert(op_t op, int arg, type_t *tp, tnode_t *tn) 2279 { 2280 tnode_t *ntn; 2281 tspec_t nt, ot; 2282 2283 nt = tp->t_tspec; 2284 ot = tn->tn_type->t_tspec; 2285 2286 if (allow_trad && allow_c90 && op == FARG) 2287 check_prototype_conversion(arg, nt, ot, tp, tn); 2288 2289 if (nt == BOOL) { 2290 /* No further checks. */ 2291 2292 } else if (is_integer(nt)) { 2293 if (ot == BOOL) { 2294 /* No further checks. */ 2295 } else if (is_integer(ot)) { 2296 convert_integer_from_integer(op, arg, nt, ot, tp, tn); 2297 } else if (is_floating(ot)) { 2298 /* No further checks. */ 2299 } else if (ot == PTR) { 2300 convert_integer_from_pointer(op, nt, tp, tn); 2301 } 2302 2303 } else if (is_floating(nt)) { 2304 /* No further checks. */ 2305 2306 } else if (nt == PTR) { 2307 if (is_null_pointer(tn)) { 2308 /* a null pointer may be assigned to any pointer. */ 2309 } else if (ot == PTR && op == CVT) { 2310 convert_pointer_from_pointer(tp, tn); 2311 } 2312 } 2313 2314 ntn = expr_alloc_tnode(); 2315 ntn->tn_op = CVT; 2316 ntn->tn_type = tp; 2317 ntn->tn_cast = op == CVT; 2318 ntn->tn_sys |= tn->tn_sys; 2319 ntn->tn_right = NULL; 2320 if (tn->tn_op != CON || nt == VOID) { 2321 ntn->tn_left = tn; 2322 } else { 2323 ntn->tn_op = CON; 2324 ntn->tn_val = expr_zero_alloc(sizeof(*ntn->tn_val)); 2325 convert_constant(op, arg, ntn->tn_type, ntn->tn_val, 2326 tn->tn_val); 2327 } 2328 2329 return ntn; 2330 } 2331 2332 static bool 2333 should_warn_about_prototype_conversion(tspec_t nt, 2334 tspec_t ot, const tnode_t *ptn) 2335 { 2336 2337 if (nt == ot) 2338 return false; 2339 2340 if (nt == ENUM && ot == INT) 2341 return false; 2342 2343 if (is_floating(nt) != is_floating(ot) || 2344 portable_size_in_bits(nt) != portable_size_in_bits(ot)) { 2345 /* representation and/or width change */ 2346 if (!is_integer(ot)) 2347 return true; 2348 /* 2349 * XXX: Investigate whether this rule makes sense; see 2350 * tests/usr.bin/xlint/lint1/platform_long.c. 2351 */ 2352 return portable_size_in_bits(ot) > portable_size_in_bits(INT); 2353 } 2354 2355 if (!hflag) 2356 return false; 2357 2358 /* 2359 * If the types differ only in sign and the argument has the same 2360 * representation in both types, print no warning. 2361 */ 2362 if (ptn->tn_op == CON && is_integer(nt) && 2363 signed_type(nt) == signed_type(ot) && 2364 !msb(ptn->tn_val->v_quad, ot)) 2365 return false; 2366 2367 return true; 2368 } 2369 2370 /* 2371 * Warn if a prototype causes a type conversion that is different from what 2372 * would happen to the same argument in the absence of a prototype. This 2373 * check is intended for code that needs to stay compatible with pre-C90 C. 2374 * 2375 * Errors/warnings about illegal type combinations are already printed 2376 * in check_assign_types_compatible(). 2377 */ 2378 static void 2379 check_prototype_conversion(int arg, tspec_t nt, tspec_t ot, type_t *tp, 2380 tnode_t *tn) 2381 { 2382 tnode_t *ptn; 2383 2384 if (!is_arithmetic(nt) || !is_arithmetic(ot)) 2385 return; 2386 2387 /* 2388 * If the type of the formal parameter is char/short, a warning 2389 * would be useless, because functions declared the old style 2390 * can't expect char/short arguments. 2391 */ 2392 if (nt == CHAR || nt == SCHAR || nt == UCHAR || 2393 nt == SHORT || nt == USHORT) 2394 return; 2395 2396 /* apply the default promotion */ 2397 ptn = promote(NOOP, true, tn); 2398 ot = ptn->tn_type->t_tspec; 2399 2400 if (should_warn_about_prototype_conversion(nt, ot, ptn)) { 2401 /* argument #%d is converted from '%s' to '%s' ... */ 2402 warning(259, arg, type_name(tn->tn_type), type_name(tp)); 2403 } 2404 } 2405 2406 /* 2407 * When converting a large integer type to a small integer type, in some 2408 * cases the value of the actual expression is further restricted than the 2409 * type bounds, such as in (expr & 0xFF) or (expr % 100) or (expr >> 24). 2410 * 2411 * See new_tnode, the '#if 0' code for SHR. 2412 */ 2413 static bool 2414 can_represent(const type_t *tp, const tnode_t *tn) 2415 { 2416 2417 debug_step("%s: type '%s'", __func__, type_name(tp)); 2418 debug_node(tn); 2419 2420 uint64_t nmask = value_bits(ic_length_in_bits(tp)); 2421 if (!is_uinteger(tp->t_tspec)) 2422 nmask >>= 1; 2423 2424 integer_constraints c = ic_expr(tn); 2425 if ((~c.bclr & ~nmask) == 0) 2426 return true; 2427 2428 return false; 2429 } 2430 2431 static void 2432 convert_integer_from_integer(op_t op, int arg, tspec_t nt, tspec_t ot, 2433 type_t *tp, tnode_t *tn) 2434 { 2435 2436 if (tn->tn_op == CON) 2437 return; 2438 2439 if (op == CVT) 2440 return; 2441 2442 if (Pflag && pflag && aflag > 0 && 2443 portable_size_in_bits(nt) > portable_size_in_bits(ot) && 2444 is_uinteger(nt) != is_uinteger(ot)) { 2445 if (op == FARG) { 2446 /* conversion to '%s' may sign-extend ... */ 2447 warning(297, type_name(tp), arg); 2448 } else { 2449 /* conversion to '%s' may sign-extend ... */ 2450 warning(131, type_name(tp)); 2451 } 2452 } 2453 2454 if (Pflag && portable_size_in_bits(nt) > portable_size_in_bits(ot) && 2455 (tn->tn_op == PLUS || tn->tn_op == MINUS || tn->tn_op == MULT || 2456 tn->tn_op == SHL)) { 2457 /* suggest cast from '%s' to '%s' on op '%s' to ... */ 2458 warning(324, type_name(gettyp(ot)), type_name(tp), 2459 op_name(tn->tn_op)); 2460 } 2461 2462 if (aflag > 0 && 2463 portable_size_in_bits(nt) < portable_size_in_bits(ot) && 2464 (ot == LONG || ot == ULONG || ot == QUAD || ot == UQUAD || 2465 aflag > 1) && 2466 !can_represent(tp, tn)) { 2467 if (op == FARG) { 2468 /* conversion from '%s' to '%s' may lose ... */ 2469 warning(298, 2470 type_name(tn->tn_type), type_name(tp), arg); 2471 } else { 2472 /* conversion from '%s' to '%s' may lose accuracy */ 2473 warning(132, 2474 type_name(tn->tn_type), type_name(tp)); 2475 } 2476 } 2477 } 2478 2479 static void 2480 convert_integer_from_pointer(op_t op, tspec_t nt, type_t *tp, tnode_t *tn) 2481 { 2482 2483 if (tn->tn_op == CON) 2484 return; 2485 if (op != CVT) 2486 return; /* We got already an error. */ 2487 if (portable_size_in_bits(nt) >= portable_size_in_bits(PTR)) 2488 return; 2489 2490 if (pflag && size_in_bits(nt) >= size_in_bits(PTR)) { 2491 /* conversion of pointer to '%s' may lose bits */ 2492 warning(134, type_name(tp)); 2493 } else { 2494 /* conversion of pointer to '%s' loses bits */ 2495 warning(133, type_name(tp)); 2496 } 2497 } 2498 2499 static bool 2500 struct_starts_with(const type_t *struct_tp, const type_t *member_tp) 2501 { 2502 2503 return struct_tp->t_str->sou_first_member != NULL && 2504 eqtype(struct_tp->t_str->sou_first_member->s_type, member_tp, 2505 true, false, NULL); 2506 } 2507 2508 static bool 2509 is_byte_array(const type_t *tp) 2510 { 2511 2512 return tp->t_tspec == ARRAY && 2513 (tp->t_subt->t_tspec == CHAR || tp->t_subt->t_tspec == UCHAR); 2514 } 2515 2516 static bool 2517 should_warn_about_pointer_cast(const type_t *nstp, tspec_t nst, 2518 const type_t *ostp, tspec_t ost) 2519 { 2520 2521 while (nst == ARRAY) 2522 nstp = nstp->t_subt, nst = nstp->t_tspec; 2523 while (ost == ARRAY) 2524 ostp = ostp->t_subt, ost = ostp->t_tspec; 2525 2526 if (nst == STRUCT && ost == STRUCT && 2527 (struct_starts_with(nstp, ostp) || 2528 struct_starts_with(ostp, nstp))) 2529 return false; 2530 2531 if (is_incomplete(nstp) || is_incomplete(ostp)) 2532 return false; 2533 2534 if (nst == CHAR || nst == UCHAR) 2535 return false; /* for the sake of traditional C code */ 2536 if (ost == CHAR || ost == UCHAR) 2537 return false; /* for the sake of traditional C code */ 2538 2539 /* Allow cast between pointers to sockaddr variants. */ 2540 if (nst == STRUCT && ost == STRUCT) { 2541 const sym_t *nmem = nstp->t_str->sou_first_member; 2542 const sym_t *omem = ostp->t_str->sou_first_member; 2543 while (nmem != NULL && omem != NULL && 2544 eqtype(nmem->s_type, omem->s_type, true, false, NULL)) 2545 nmem = nmem->s_next, omem = omem->s_next; 2546 if (nmem != NULL && is_byte_array(nmem->s_type)) 2547 return false; 2548 if (omem != NULL && is_byte_array(omem->s_type)) 2549 return false; 2550 if (nmem == NULL && omem == NULL) 2551 return false; 2552 } 2553 2554 if (is_struct_or_union(nst) && nstp->t_str != ostp->t_str) 2555 return true; 2556 2557 return portable_size_in_bits(nst) != portable_size_in_bits(ost); 2558 } 2559 2560 static void 2561 convert_pointer_from_pointer(type_t *ntp, tnode_t *tn) 2562 { 2563 const type_t *nstp, *otp, *ostp; 2564 tspec_t nst, ost; 2565 const char *nts, *ots; 2566 2567 nstp = ntp->t_subt; 2568 otp = tn->tn_type; 2569 ostp = otp->t_subt; 2570 nst = nstp->t_tspec; 2571 ost = ostp->t_tspec; 2572 2573 if (nst == VOID || ost == VOID) { 2574 /* TODO: C99 behaves like C90 here. */ 2575 if ((!allow_trad && !allow_c99) && (nst == FUNC || ost == FUNC)) { 2576 /* null pointers are already handled in convert() */ 2577 *(nst == FUNC ? &nts : &ots) = "function pointer"; 2578 *(nst == VOID ? &nts : &ots) = "'void *'"; 2579 /* ANSI C forbids conversion of %s to %s */ 2580 warning(303, ots, nts); 2581 } 2582 return; 2583 } else if (nst == FUNC && ost == FUNC) { 2584 return; 2585 } else if (nst == FUNC || ost == FUNC) { 2586 /* converting '%s' to '%s' is questionable */ 2587 warning(229, type_name(otp), type_name(ntp)); 2588 return; 2589 } 2590 2591 if (hflag && alignment_in_bits(nstp) > alignment_in_bits(ostp) && 2592 ost != CHAR && ost != UCHAR && 2593 !is_incomplete(ostp)) { 2594 /* converting '%s' to '%s' may cause alignment problem */ 2595 warning(135, type_name(otp), type_name(ntp)); 2596 } 2597 2598 if (cflag && should_warn_about_pointer_cast(nstp, nst, ostp, ost)) { 2599 /* pointer cast from '%s' to '%s' may be troublesome */ 2600 warning(247, type_name(otp), type_name(ntp)); 2601 } 2602 } 2603 2604 static void 2605 convert_constant_floating(op_t op, int arg, tspec_t ot, const type_t *tp, 2606 tspec_t nt, val_t *v, val_t *nv) 2607 { 2608 ldbl_t max = 0.0, min = 0.0; 2609 2610 switch (nt) { 2611 case CHAR: 2612 max = TARG_CHAR_MAX; min = TARG_CHAR_MIN; break; 2613 case UCHAR: 2614 max = TARG_UCHAR_MAX; min = 0; break; 2615 case SCHAR: 2616 max = TARG_SCHAR_MAX; min = TARG_SCHAR_MIN; break; 2617 case SHORT: 2618 max = TARG_SHRT_MAX; min = TARG_SHRT_MIN; break; 2619 case USHORT: 2620 max = TARG_USHRT_MAX; min = 0; break; 2621 case ENUM: 2622 case INT: 2623 max = TARG_INT_MAX; min = TARG_INT_MIN; break; 2624 case UINT: 2625 max = TARG_UINT_MAX; min = 0; break; 2626 case LONG: 2627 max = TARG_LONG_MAX; min = TARG_LONG_MIN; break; 2628 case ULONG: 2629 max = TARG_ULONG_MAX; min = 0; break; 2630 case QUAD: 2631 max = QUAD_MAX; min = QUAD_MIN; break; 2632 case UQUAD: 2633 max = UQUAD_MAX; min = 0; break; 2634 case FLOAT: 2635 case FCOMPLEX: 2636 max = FLT_MAX; min = -FLT_MAX; break; 2637 case DOUBLE: 2638 case DCOMPLEX: 2639 max = DBL_MAX; min = -DBL_MAX; break; 2640 case PTR: 2641 /* Got already an error because of float --> ptr */ 2642 case LDOUBLE: 2643 case LCOMPLEX: 2644 /* LINTED 248 */ 2645 max = LDBL_MAX; min = -max; break; 2646 default: 2647 lint_assert(/*CONSTCOND*/false); 2648 } 2649 if (v->v_ldbl > max || v->v_ldbl < min) { 2650 lint_assert(nt != LDOUBLE); 2651 if (op == FARG) { 2652 /* conversion of '%s' to '%s' is out of range, ... */ 2653 warning(295, 2654 type_name(gettyp(ot)), type_name(tp), arg); 2655 } else { 2656 /* conversion of '%s' to '%s' is out of range */ 2657 warning(119, 2658 type_name(gettyp(ot)), type_name(tp)); 2659 } 2660 v->v_ldbl = v->v_ldbl > 0 ? max : min; 2661 } 2662 2663 if (nt == FLOAT) { 2664 nv->v_ldbl = (float)v->v_ldbl; 2665 } else if (nt == DOUBLE) { 2666 nv->v_ldbl = (double)v->v_ldbl; 2667 } else if (nt == LDOUBLE) { 2668 nv->v_ldbl = v->v_ldbl; 2669 } else { 2670 nv->v_quad = (int64_t)v->v_ldbl; 2671 } 2672 } 2673 2674 static bool 2675 convert_constant_to_floating(tspec_t nt, val_t *nv, 2676 tspec_t ot, const val_t *v) 2677 { 2678 if (nt == FLOAT) { 2679 nv->v_ldbl = (ot == PTR || is_uinteger(ot)) ? 2680 (float)(uint64_t)v->v_quad : (float)v->v_quad; 2681 } else if (nt == DOUBLE) { 2682 nv->v_ldbl = (ot == PTR || is_uinteger(ot)) ? 2683 (double)(uint64_t)v->v_quad : (double)v->v_quad; 2684 } else if (nt == LDOUBLE) { 2685 nv->v_ldbl = (ot == PTR || is_uinteger(ot)) ? 2686 (ldbl_t)(uint64_t)v->v_quad : (ldbl_t)v->v_quad; 2687 } else 2688 return false; 2689 return true; 2690 } 2691 2692 /* 2693 * Print a warning if bits which were set are lost due to the conversion. 2694 * This can happen with operator ORASS only. 2695 */ 2696 static void 2697 convert_constant_check_range_bitor(size_t nsz, size_t osz, const val_t *v, 2698 uint64_t xmask, op_t op) 2699 { 2700 if (nsz < osz && (v->v_quad & xmask) != 0) { 2701 /* constant truncated by conversion, op '%s' */ 2702 warning(306, op_name(op)); 2703 } 2704 } 2705 2706 /* 2707 * Print a warning if additional bits are not all 1 2708 * and the most significant bit of the old value is 1, 2709 * or if at least one (but not all) removed bit was 0. 2710 */ 2711 static void 2712 convert_constant_check_range_bitand(size_t nsz, size_t osz, 2713 uint64_t xmask, const val_t *nv, 2714 tspec_t ot, const val_t *v, 2715 const type_t *tp, op_t op) 2716 { 2717 if (nsz > osz && 2718 (nv->v_quad & bit((unsigned int)(osz - 1))) != 0 && 2719 (nv->v_quad & xmask) != xmask) { 2720 /* extra bits set to 0 in conversion of '%s' to '%s', ... */ 2721 warning(309, type_name(gettyp(ot)), 2722 type_name(tp), op_name(op)); 2723 } else if (nsz < osz && 2724 (v->v_quad & xmask) != xmask && 2725 (v->v_quad & xmask) != 0) { 2726 /* constant truncated by conversion, op '%s' */ 2727 warning(306, op_name(op)); 2728 } 2729 } 2730 2731 static void 2732 convert_constant_check_range_signed(op_t op, int arg) 2733 { 2734 if (op == ASSIGN) { 2735 /* assignment of negative constant to unsigned type */ 2736 warning(164); 2737 } else if (op == INIT) { 2738 /* initialization of unsigned with negative constant */ 2739 warning(221); 2740 } else if (op == FARG) { 2741 /* conversion of negative constant to unsigned type, ... */ 2742 warning(296, arg); 2743 } else if (modtab[op].m_comparison) { 2744 /* handled by check_integer_comparison() */ 2745 } else { 2746 /* conversion of negative constant to unsigned type */ 2747 warning(222); 2748 } 2749 } 2750 2751 /* 2752 * Loss of significant bit(s). All truncated bits 2753 * of unsigned types or all truncated bits plus the 2754 * msb of the target for signed types are considered 2755 * to be significant bits. Loss of significant bits 2756 * means that at least one of the bits was set in an 2757 * unsigned type or that at least one but not all of 2758 * the bits was set in a signed type. 2759 * Loss of significant bits means that it is not 2760 * possible, also not with necessary casts, to convert 2761 * back to the original type. A example for a 2762 * necessary cast is: 2763 * char c; int i; c = 128; 2764 * i = c; ** yields -128 ** 2765 * i = (unsigned char)c; ** yields 128 ** 2766 */ 2767 static void 2768 convert_constant_check_range_truncated(op_t op, int arg, const type_t *tp, 2769 tspec_t ot) 2770 { 2771 if (op == ASSIGN && tp->t_bitfield) { 2772 /* precision lost in bit-field assignment */ 2773 warning(166); 2774 } else if (op == ASSIGN) { 2775 /* constant truncated by assignment */ 2776 warning(165); 2777 } else if (op == INIT && tp->t_bitfield) { 2778 /* bit-field initializer does not fit */ 2779 warning(180); 2780 } else if (op == INIT) { 2781 /* initializer does not fit */ 2782 warning(178); 2783 } else if (op == CASE) { 2784 /* case label affected by conversion */ 2785 warning(196); 2786 } else if (op == FARG) { 2787 /* conversion of '%s' to '%s' is out of range, arg #%d */ 2788 warning(295, 2789 type_name(gettyp(ot)), type_name(tp), arg); 2790 } else { 2791 /* conversion of '%s' to '%s' is out of range */ 2792 warning(119, 2793 type_name(gettyp(ot)), type_name(tp)); 2794 } 2795 } 2796 2797 static void 2798 convert_constant_check_range_loss(op_t op, int arg, const type_t *tp, 2799 tspec_t ot) 2800 { 2801 if (op == ASSIGN && tp->t_bitfield) { 2802 /* precision lost in bit-field assignment */ 2803 warning(166); 2804 } else if (op == INIT && tp->t_bitfield) { 2805 /* bit-field initializer out of range */ 2806 warning(11); 2807 } else if (op == CASE) { 2808 /* case label affected by conversion */ 2809 warning(196); 2810 } else if (op == FARG) { 2811 /* conversion of '%s' to '%s' is out of range, arg #%d */ 2812 warning(295, 2813 type_name(gettyp(ot)), type_name(tp), arg); 2814 } else { 2815 /* conversion of '%s' to '%s' is out of range */ 2816 warning(119, 2817 type_name(gettyp(ot)), type_name(tp)); 2818 } 2819 } 2820 2821 static void 2822 convert_constant_check_range(tspec_t ot, const type_t *tp, tspec_t nt, 2823 op_t op, int arg, const val_t *v, val_t *nv) 2824 { 2825 unsigned int osz, nsz; 2826 uint64_t xmask, xmsk1; 2827 2828 osz = size_in_bits(ot); 2829 nsz = tp->t_bitfield ? tp->t_flen : size_in_bits(nt); 2830 xmask = value_bits(nsz) ^ value_bits(osz); 2831 xmsk1 = value_bits(nsz) ^ value_bits(osz - 1); 2832 /* 2833 * For bitwise operations we are not interested in the 2834 * value, but in the bits itself. 2835 */ 2836 if (op == ORASS || op == BITOR || op == BITXOR) { 2837 convert_constant_check_range_bitor(nsz, osz, v, xmask, op); 2838 } else if (op == ANDASS || op == BITAND) { 2839 convert_constant_check_range_bitand(nsz, osz, xmask, nv, ot, 2840 v, tp, op); 2841 } else if ((nt != PTR && is_uinteger(nt)) && 2842 (ot != PTR && !is_uinteger(ot)) && 2843 v->v_quad < 0) { 2844 convert_constant_check_range_signed(op, arg); 2845 } else if (nv->v_quad != v->v_quad && nsz <= osz && 2846 (v->v_quad & xmask) != 0 && 2847 (is_uinteger(ot) || (v->v_quad & xmsk1) != xmsk1)) { 2848 convert_constant_check_range_truncated(op, arg, tp, ot); 2849 } else if (nv->v_quad != v->v_quad) { 2850 convert_constant_check_range_loss(op, arg, tp, ot); 2851 } 2852 } 2853 2854 /* 2855 * Converts a typed constant to a constant of another type. 2856 * 2857 * op operator which requires conversion 2858 * arg if op is FARG, # of argument 2859 * tp type in which to convert the constant 2860 * nv new constant 2861 * v old constant 2862 */ 2863 void 2864 convert_constant(op_t op, int arg, const type_t *tp, val_t *nv, val_t *v) 2865 { 2866 tspec_t ot, nt; 2867 unsigned int sz; 2868 bool range_check; 2869 2870 /* 2871 * TODO: make 'v' const; the name of this function does not suggest 2872 * that it modifies 'v'. 2873 */ 2874 ot = v->v_tspec; 2875 nt = nv->v_tspec = tp->t_tspec; 2876 range_check = false; 2877 2878 if (nt == BOOL) { /* C99 6.3.1.2 */ 2879 nv->v_unsigned_since_c90 = false; 2880 nv->v_quad = is_nonzero_val(v) ? 1 : 0; 2881 return; 2882 } 2883 2884 if (ot == FLOAT || ot == DOUBLE || ot == LDOUBLE) { 2885 convert_constant_floating(op, arg, ot, tp, nt, v, nv); 2886 } else if (!convert_constant_to_floating(nt, nv, ot, v)) { 2887 range_check = true; /* Check for lost precision. */ 2888 nv->v_quad = v->v_quad; 2889 } 2890 2891 if (allow_trad && allow_c90 && v->v_unsigned_since_c90 && 2892 (is_floating(nt) || ( 2893 (is_integer(nt) && !is_uinteger(nt) && 2894 portable_size_in_bits(nt) > portable_size_in_bits(ot))))) { 2895 /* ANSI C treats constant as unsigned */ 2896 warning(157); 2897 v->v_unsigned_since_c90 = false; 2898 } 2899 2900 if (is_integer(nt)) { 2901 sz = tp->t_bitfield ? tp->t_flen : size_in_bits(nt); 2902 nv->v_quad = convert_integer(nv->v_quad, nt, sz); 2903 } 2904 2905 if (range_check && op != CVT) 2906 convert_constant_check_range(ot, tp, nt, op, arg, v, nv); 2907 } 2908 2909 /* 2910 * Called if incompatible types were detected. 2911 * Prints a appropriate warning. 2912 */ 2913 static void 2914 warn_incompatible_types(op_t op, 2915 const type_t *ltp, tspec_t lt, 2916 const type_t *rtp, tspec_t rt) 2917 { 2918 const mod_t *mp; 2919 2920 mp = &modtab[op]; 2921 2922 if (lt == VOID || (mp->m_binary && rt == VOID)) { 2923 /* void type illegal in expression */ 2924 error(109); 2925 } else if (op == ASSIGN) { 2926 if (is_struct_or_union(lt) && is_struct_or_union(rt)) { 2927 /* assignment of different structures (%s != %s) */ 2928 error(240, tspec_name(lt), tspec_name(rt)); 2929 } else { 2930 /* cannot assign to '%s' from '%s' */ 2931 error(171, type_name(ltp), type_name(rtp)); 2932 } 2933 } else if (mp->m_binary) { 2934 /* operands of '%s' have incompatible types '%s' and '%s' */ 2935 error(107, mp->m_name, tspec_name(lt), tspec_name(rt)); 2936 } else { 2937 lint_assert(rt == NOTSPEC); 2938 /* operand of '%s' has invalid type '%s' */ 2939 error(108, mp->m_name, type_name(ltp)); 2940 } 2941 } 2942 2943 /* 2944 * Called if incompatible pointer types are detected. 2945 * Print an appropriate warning. 2946 */ 2947 static void 2948 warn_incompatible_pointers(const mod_t *mp, 2949 const type_t *ltp, const type_t *rtp) 2950 { 2951 tspec_t lt, rt; 2952 2953 lint_assert(ltp->t_tspec == PTR); 2954 lint_assert(rtp->t_tspec == PTR); 2955 2956 lt = ltp->t_subt->t_tspec; 2957 rt = rtp->t_subt->t_tspec; 2958 2959 if (is_struct_or_union(lt) && is_struct_or_union(rt)) { 2960 if (mp == NULL) { 2961 /* illegal structure pointer combination */ 2962 warning(244); 2963 } else { 2964 /* incompatible structure pointers: '%s' '%s' '%s' */ 2965 warning(245, type_name(ltp), mp->m_name, type_name(rtp)); 2966 } 2967 } else { 2968 if (mp == NULL) { 2969 /* illegal combination of '%s' and '%s' */ 2970 warning(184, type_name(ltp), type_name(rtp)); 2971 } else { 2972 /* illegal combination of '%s' and '%s', op '%s' */ 2973 warning(124, 2974 type_name(ltp), type_name(rtp), mp->m_name); 2975 } 2976 } 2977 } 2978 2979 /* Return a type based on tp1, with added qualifiers from tp2. */ 2980 static type_t * 2981 merge_qualifiers(type_t *tp1, const type_t *tp2) 2982 { 2983 type_t *ntp, *nstp; 2984 bool c1, c2, v1, v2; 2985 2986 lint_assert(tp1->t_tspec == PTR); 2987 lint_assert(tp2->t_tspec == PTR); 2988 2989 c1 = tp1->t_subt->t_const; 2990 c2 = tp2->t_subt->t_const; 2991 v1 = tp1->t_subt->t_volatile; 2992 v2 = tp2->t_subt->t_volatile; 2993 2994 if (c1 == (c1 | c2) && v1 == (v1 | v2)) 2995 return tp1; 2996 2997 nstp = expr_dup_type(tp1->t_subt); 2998 nstp->t_const |= c2; 2999 nstp->t_volatile |= v2; 3000 3001 ntp = expr_dup_type(tp1); 3002 ntp->t_subt = nstp; 3003 return ntp; 3004 } 3005 3006 /* 3007 * Returns true if the given structure or union has a constant member 3008 * (maybe recursively). 3009 */ 3010 static bool 3011 has_constant_member(const type_t *tp) 3012 { 3013 sym_t *m; 3014 3015 lint_assert(is_struct_or_union(tp->t_tspec)); 3016 3017 for (m = tp->t_str->sou_first_member; m != NULL; m = m->s_next) { 3018 const type_t *mtp = m->s_type; 3019 if (mtp->t_const) 3020 return true; 3021 if (is_struct_or_union(mtp->t_tspec) && 3022 has_constant_member(mtp)) 3023 return true; 3024 } 3025 return false; 3026 } 3027 3028 /* 3029 * Create a new node for one of the operators POINT and ARROW. 3030 */ 3031 static tnode_t * 3032 build_struct_access(op_t op, bool sys, tnode_t *ln, tnode_t *rn) 3033 { 3034 tnode_t *ntn, *ctn; 3035 bool nolval; 3036 3037 lint_assert(rn->tn_op == NAME); 3038 lint_assert(is_member(rn->tn_sym)); 3039 3040 /* 3041 * Remember if the left operand is an lvalue (structure members 3042 * are lvalues if and only if the structure itself is an lvalue). 3043 */ 3044 nolval = op == POINT && !ln->tn_lvalue; 3045 3046 if (op == POINT) { 3047 ln = build_address(sys, ln, true); 3048 } else if (ln->tn_type->t_tspec != PTR) { 3049 lint_assert(!allow_c90); 3050 lint_assert(is_integer(ln->tn_type->t_tspec)); 3051 ln = convert(NOOP, 0, expr_derive_type(gettyp(VOID), PTR), ln); 3052 } 3053 3054 ctn = build_integer_constant(PTRDIFF_TSPEC, 3055 rn->tn_sym->u.s_member.sm_offset_in_bits / CHAR_SIZE); 3056 3057 ntn = new_tnode(PLUS, sys, expr_derive_type(rn->tn_type, PTR), 3058 ln, ctn); 3059 if (ln->tn_op == CON) 3060 ntn = fold(ntn); 3061 3062 if (rn->tn_type->t_bitfield) { 3063 ntn = new_tnode(FSEL, sys, ntn->tn_type->t_subt, ntn, NULL); 3064 } else { 3065 ntn = new_tnode(INDIR, sys, ntn->tn_type->t_subt, ntn, NULL); 3066 } 3067 3068 if (nolval) 3069 ntn->tn_lvalue = false; 3070 3071 return ntn; 3072 } 3073 3074 /* 3075 * Create a node for INCAFT, INCBEF, DECAFT and DECBEF. 3076 */ 3077 static tnode_t * 3078 build_prepost_incdec(op_t op, bool sys, tnode_t *ln) 3079 { 3080 tnode_t *cn, *ntn; 3081 3082 lint_assert(ln != NULL); 3083 3084 if (ln->tn_type->t_tspec == PTR) { 3085 cn = subt_size_in_bytes(ln->tn_type); 3086 } else { 3087 cn = build_integer_constant(INT, (int64_t)1); 3088 } 3089 ntn = new_tnode(op, sys, ln->tn_type, ln, cn); 3090 3091 return ntn; 3092 } 3093 3094 /* 3095 * Create a node for REAL, IMAG 3096 */ 3097 static tnode_t * 3098 build_real_imag(op_t op, bool sys, tnode_t *ln) 3099 { 3100 tnode_t *cn, *ntn; 3101 3102 lint_assert(ln != NULL); 3103 3104 if (ln->tn_op == NAME) { 3105 /* 3106 * This may be too much, but it avoids wrong warnings. 3107 * See d_c99_complex_split.c. 3108 */ 3109 mark_as_used(ln->tn_sym, false, false); 3110 mark_as_set(ln->tn_sym); 3111 } 3112 3113 switch (ln->tn_type->t_tspec) { 3114 case LCOMPLEX: 3115 /* XXX: integer and LDOUBLE don't match. */ 3116 cn = build_integer_constant(LDOUBLE, (int64_t)1); 3117 break; 3118 case DCOMPLEX: 3119 /* XXX: integer and DOUBLE don't match. */ 3120 cn = build_integer_constant(DOUBLE, (int64_t)1); 3121 break; 3122 case FCOMPLEX: 3123 /* XXX: integer and FLOAT don't match. */ 3124 cn = build_integer_constant(FLOAT, (int64_t)1); 3125 break; 3126 default: 3127 /* '__%s__' is illegal for type '%s' */ 3128 error(276, op == REAL ? "real" : "imag", 3129 type_name(ln->tn_type)); 3130 return NULL; 3131 } 3132 ntn = new_tnode(op, sys, cn->tn_type, ln, cn); 3133 ntn->tn_lvalue = true; 3134 3135 return ntn; 3136 } 3137 3138 /* 3139 * Create a tree node for the unary & operator 3140 */ 3141 static tnode_t * 3142 build_address(bool sys, tnode_t *tn, bool noign) 3143 { 3144 tspec_t t; 3145 3146 if (!noign && ((t = tn->tn_type->t_tspec) == ARRAY || t == FUNC)) { 3147 if (!allow_c90) 3148 /* '&' before array or function: ignored */ 3149 warning(127); 3150 return tn; 3151 } 3152 3153 /* eliminate &* */ 3154 if (tn->tn_op == INDIR && 3155 tn->tn_left->tn_type->t_tspec == PTR && 3156 tn->tn_left->tn_type->t_subt == tn->tn_type) { 3157 return tn->tn_left; 3158 } 3159 3160 return new_tnode(ADDR, sys, expr_derive_type(tn->tn_type, PTR), 3161 tn, NULL); 3162 } 3163 3164 /* 3165 * Create a node for operators PLUS and MINUS. 3166 */ 3167 static tnode_t * 3168 build_plus_minus(op_t op, bool sys, tnode_t *ln, tnode_t *rn) 3169 { 3170 3171 /* If pointer and integer, then pointer to the lhs. */ 3172 if (rn->tn_type->t_tspec == PTR && is_integer(ln->tn_type->t_tspec)) { 3173 tnode_t *tmp = ln; 3174 ln = rn; 3175 rn = tmp; 3176 } 3177 3178 /* pointer +- integer */ 3179 if (ln->tn_type->t_tspec == PTR && rn->tn_type->t_tspec != PTR) { 3180 lint_assert(is_integer(rn->tn_type->t_tspec)); 3181 3182 check_ctype_macro_invocation(ln, rn); 3183 check_enum_array_index(ln, rn); 3184 3185 tnode_t *elsz = subt_size_in_bytes(ln->tn_type); 3186 if (rn->tn_type->t_tspec != elsz->tn_type->t_tspec) 3187 rn = convert(NOOP, 0, elsz->tn_type, rn); 3188 3189 tnode_t *prod = new_tnode(MULT, sys, rn->tn_type, rn, elsz); 3190 if (rn->tn_op == CON) 3191 prod = fold(prod); 3192 3193 return new_tnode(op, sys, ln->tn_type, ln, prod); 3194 } 3195 3196 /* pointer - pointer */ 3197 if (rn->tn_type->t_tspec == PTR) { 3198 lint_assert(ln->tn_type->t_tspec == PTR); 3199 lint_assert(op == MINUS); 3200 3201 type_t *ptrdiff = gettyp(PTRDIFF_TSPEC); 3202 tnode_t *raw_diff = new_tnode(op, sys, ptrdiff, ln, rn); 3203 if (ln->tn_op == CON && rn->tn_op == CON) 3204 raw_diff = fold(raw_diff); 3205 3206 tnode_t *elsz = subt_size_in_bytes(ln->tn_type); 3207 balance(NOOP, &raw_diff, &elsz); 3208 3209 return new_tnode(DIV, sys, ptrdiff, raw_diff, elsz); 3210 } 3211 3212 return new_tnode(op, sys, ln->tn_type, ln, rn); 3213 } 3214 3215 /* 3216 * Create a node for operators SHL and SHR. 3217 */ 3218 static tnode_t * 3219 build_bit_shift(op_t op, bool sys, tnode_t *ln, tnode_t *rn) 3220 { 3221 tspec_t t; 3222 tnode_t *ntn; 3223 3224 if ((t = rn->tn_type->t_tspec) != INT && t != UINT) 3225 rn = convert(CVT, 0, gettyp(INT), rn); 3226 ntn = new_tnode(op, sys, ln->tn_type, ln, rn); 3227 return ntn; 3228 } 3229 3230 /* 3231 * Create a node for COLON. 3232 */ 3233 static tnode_t * 3234 build_colon(bool sys, tnode_t *ln, tnode_t *rn) 3235 { 3236 tspec_t lt, rt, pdt; 3237 type_t *tp; 3238 tnode_t *ntn; 3239 3240 lt = ln->tn_type->t_tspec; 3241 rt = rn->tn_type->t_tspec; 3242 pdt = PTRDIFF_TSPEC; 3243 3244 /* 3245 * Arithmetic types are balanced, all other type combinations 3246 * still need to be handled. 3247 */ 3248 if (is_arithmetic(lt) && is_arithmetic(rt)) { 3249 tp = ln->tn_type; 3250 } else if (lt == BOOL && rt == BOOL) { 3251 tp = ln->tn_type; 3252 } else if (lt == VOID || rt == VOID) { 3253 tp = gettyp(VOID); 3254 } else if (is_struct_or_union(lt)) { 3255 /* Both types must be identical. */ 3256 lint_assert(is_struct_or_union(rt)); 3257 lint_assert(ln->tn_type->t_str == rn->tn_type->t_str); 3258 if (is_incomplete(ln->tn_type)) { 3259 /* unknown operand size, op %s */ 3260 error(138, op_name(COLON)); 3261 return NULL; 3262 } 3263 tp = ln->tn_type; 3264 } else if (lt == PTR && is_integer(rt)) { 3265 if (rt != pdt) { 3266 rn = convert(NOOP, 0, gettyp(pdt), rn); 3267 rt = pdt; 3268 } 3269 tp = ln->tn_type; 3270 } else if (rt == PTR && is_integer(lt)) { 3271 if (lt != pdt) { 3272 ln = convert(NOOP, 0, gettyp(pdt), ln); 3273 lt = pdt; 3274 } 3275 tp = rn->tn_type; 3276 } else if (lt == PTR && ln->tn_type->t_subt->t_tspec == VOID) { 3277 tp = merge_qualifiers(rn->tn_type, ln->tn_type); 3278 } else if (rt == PTR && rn->tn_type->t_subt->t_tspec == VOID) { 3279 tp = merge_qualifiers(ln->tn_type, rn->tn_type); 3280 } else { 3281 /* 3282 * XXX For now we simply take the left type. This is 3283 * probably wrong, if one type contains a function prototype 3284 * and the other one, at the same place, only an old style 3285 * declaration. 3286 */ 3287 tp = merge_qualifiers(ln->tn_type, rn->tn_type); 3288 } 3289 3290 ntn = new_tnode(COLON, sys, tp, ln, rn); 3291 3292 return ntn; 3293 } 3294 3295 /* 3296 * Create a node for an assignment operator (both = and op= ). 3297 */ 3298 static tnode_t * 3299 build_assignment(op_t op, bool sys, tnode_t *ln, tnode_t *rn) 3300 { 3301 tspec_t lt, rt; 3302 tnode_t *ntn, *ctn; 3303 3304 lint_assert(ln != NULL); 3305 lint_assert(rn != NULL); 3306 3307 lt = ln->tn_type->t_tspec; 3308 rt = rn->tn_type->t_tspec; 3309 3310 if ((op == ADDASS || op == SUBASS) && lt == PTR) { 3311 lint_assert(is_integer(rt)); 3312 ctn = subt_size_in_bytes(ln->tn_type); 3313 if (rn->tn_type->t_tspec != ctn->tn_type->t_tspec) 3314 rn = convert(NOOP, 0, ctn->tn_type, rn); 3315 rn = new_tnode(MULT, sys, rn->tn_type, rn, ctn); 3316 if (rn->tn_left->tn_op == CON) 3317 rn = fold(rn); 3318 } 3319 3320 if ((op == ASSIGN || op == RETURN || op == INIT) && 3321 (lt == STRUCT || rt == STRUCT)) { 3322 lint_assert(lt == rt); 3323 lint_assert(ln->tn_type->t_str == rn->tn_type->t_str); 3324 if (is_incomplete(ln->tn_type)) { 3325 if (op == RETURN) { 3326 /* cannot return incomplete type */ 3327 error(212); 3328 } else { 3329 /* unknown operand size, op %s */ 3330 error(138, op_name(op)); 3331 } 3332 return NULL; 3333 } 3334 } 3335 3336 if (op == SHLASS) { 3337 if (portable_size_in_bits(lt) < portable_size_in_bits(rt)) { 3338 if (hflag) 3339 /* semantics of '%s' change in ANSI C; ... */ 3340 warning(118, "<<="); 3341 } 3342 } else if (op != SHRASS) { 3343 if (op == ASSIGN || lt != PTR) { 3344 if (lt != rt || 3345 (ln->tn_type->t_bitfield && rn->tn_op == CON)) { 3346 rn = convert(op, 0, ln->tn_type, rn); 3347 rt = lt; 3348 } 3349 } 3350 } 3351 3352 ntn = new_tnode(op, sys, ln->tn_type, ln, rn); 3353 3354 return ntn; 3355 } 3356 3357 /* 3358 * Get the size in bytes of type tp->t_subt, as a constant expression of type 3359 * ptrdiff_t as seen from the target platform. 3360 */ 3361 static tnode_t * 3362 subt_size_in_bytes(type_t *tp) 3363 { 3364 int elem, elsz_in_bits; 3365 3366 lint_assert(tp->t_tspec == PTR); 3367 tp = tp->t_subt; 3368 3369 elem = 1; 3370 elsz_in_bits = 0; 3371 3372 while (tp->t_tspec == ARRAY) { 3373 elem *= tp->t_dim; 3374 tp = tp->t_subt; 3375 } 3376 3377 switch (tp->t_tspec) { 3378 case FUNC: 3379 /* pointer to function is not allowed here */ 3380 error(110); 3381 break; 3382 case VOID: 3383 /* cannot do pointer arithmetic on operand of unknown size */ 3384 gnuism(136); 3385 break; 3386 case STRUCT: 3387 case UNION: 3388 if ((elsz_in_bits = tp->t_str->sou_size_in_bits) == 0) 3389 /* cannot do pointer arithmetic on operand of ... */ 3390 error(136); 3391 break; 3392 case ENUM: 3393 if (is_incomplete(tp)) { 3394 /* cannot do pointer arithmetic on operand of ... */ 3395 warning(136); 3396 } 3397 /* FALLTHROUGH */ 3398 default: 3399 if ((elsz_in_bits = size_in_bits(tp->t_tspec)) == 0) { 3400 /* cannot do pointer arithmetic on operand of ... */ 3401 error(136); 3402 } else { 3403 lint_assert(elsz_in_bits != -1); 3404 } 3405 break; 3406 } 3407 3408 if (elem == 0 && elsz_in_bits != 0) { 3409 /* cannot do pointer arithmetic on operand of unknown size */ 3410 error(136); 3411 } 3412 3413 if (elsz_in_bits == 0) 3414 elsz_in_bits = CHAR_SIZE; 3415 3416 return build_integer_constant(PTRDIFF_TSPEC, 3417 (int64_t)(elem * elsz_in_bits / CHAR_SIZE)); 3418 } 3419 3420 /* 3421 * XXX 3422 * Note: There appear to be a number of bugs in detecting overflow in 3423 * this function. An audit and a set of proper regression tests are needed. 3424 * --Perry Metzger, Nov. 16, 2001 3425 */ 3426 /* 3427 * Do only as much as necessary to compute constant expressions. 3428 * Called only if the operator allows folding and all operands are constants. 3429 */ 3430 static tnode_t * 3431 fold(tnode_t *tn) 3432 { 3433 val_t *v; 3434 tspec_t t; 3435 bool utyp, ovfl; 3436 int64_t sl, sr = 0, q = 0, mask; 3437 uint64_t ul, ur = 0; 3438 tnode_t *cn; 3439 3440 v = xcalloc(1, sizeof(*v)); 3441 v->v_tspec = tn->tn_type->t_tspec; 3442 3443 t = tn->tn_left->tn_type->t_tspec; 3444 utyp = !is_integer(t) || is_uinteger(t); 3445 ul = sl = tn->tn_left->tn_val->v_quad; 3446 if (is_binary(tn)) 3447 ur = sr = tn->tn_right->tn_val->v_quad; 3448 3449 mask = value_bits(size_in_bits(t)); 3450 ovfl = false; 3451 3452 switch (tn->tn_op) { 3453 case UPLUS: 3454 q = sl; 3455 break; 3456 case UMINUS: 3457 q = sl == INT64_MIN ? sl : -sl; 3458 if (sl != 0 && msb(q, t) == msb(sl, t)) 3459 ovfl = true; 3460 break; 3461 case COMPL: 3462 q = ~sl; 3463 break; 3464 case MULT: 3465 if (utyp) { 3466 q = ul * ur; 3467 if (q != (q & mask)) 3468 ovfl = true; 3469 else if ((ul != 0) && ((q / ul) != ur)) 3470 ovfl = true; 3471 } else { 3472 q = sl * sr; 3473 if (msb(q, t) != (msb(sl, t) ^ msb(sr, t))) 3474 ovfl = true; 3475 } 3476 break; 3477 case DIV: 3478 if (sr == 0) { 3479 /* division by 0 */ 3480 error(139); 3481 q = utyp ? -1 : INT64_MAX; 3482 } else { 3483 q = utyp ? (int64_t)(ul / ur) : sl / sr; 3484 } 3485 break; 3486 case MOD: 3487 if (sr == 0) { 3488 /* modulus by 0 */ 3489 error(140); 3490 q = 0; 3491 } else { 3492 q = utyp ? (int64_t)(ul % ur) : sl % sr; 3493 } 3494 break; 3495 case PLUS: 3496 q = utyp ? (int64_t)(ul + ur) : sl + sr; 3497 if (msb(sl, t) && msb(sr, t) && !msb(q, t)) 3498 ovfl = true; 3499 if (!utyp && !msb(sl, t) && !msb(sr, t) && msb(q, t)) 3500 ovfl = true; 3501 break; 3502 case MINUS: 3503 q = utyp ? (int64_t)(ul - ur) : sl - sr; 3504 if (!utyp && msb(sl, t) && !msb(sr, t) && !msb(q, t)) 3505 ovfl = true; 3506 if (!msb(sl, t) && msb(sr, t) && msb(q, t)) 3507 ovfl = true; 3508 break; 3509 case SHL: 3510 q = utyp ? (int64_t)(ul << sr) : sl << sr; 3511 break; 3512 case SHR: 3513 /* 3514 * The sign must be explicitly extended because 3515 * shifts of signed values are implementation dependent. 3516 */ 3517 q = ul >> sr; 3518 q = convert_integer(q, t, size_in_bits(t) - (int)sr); 3519 break; 3520 case LT: 3521 q = (utyp ? ul < ur : sl < sr) ? 1 : 0; 3522 break; 3523 case LE: 3524 q = (utyp ? ul <= ur : sl <= sr) ? 1 : 0; 3525 break; 3526 case GE: 3527 q = (utyp ? ul >= ur : sl >= sr) ? 1 : 0; 3528 break; 3529 case GT: 3530 q = (utyp ? ul > ur : sl > sr) ? 1 : 0; 3531 break; 3532 case EQ: 3533 q = (utyp ? ul == ur : sl == sr) ? 1 : 0; 3534 break; 3535 case NE: 3536 q = (utyp ? ul != ur : sl != sr) ? 1 : 0; 3537 break; 3538 case BITAND: 3539 q = utyp ? (int64_t)(ul & ur) : sl & sr; 3540 break; 3541 case BITXOR: 3542 q = utyp ? (int64_t)(ul ^ ur) : sl ^ sr; 3543 break; 3544 case BITOR: 3545 q = utyp ? (int64_t)(ul | ur) : sl | sr; 3546 break; 3547 default: 3548 lint_assert(/*CONSTCOND*/false); 3549 } 3550 3551 /* XXX does not work for quads. */ 3552 if (ovfl || 3553 ((uint64_t)(q | mask) != ~(uint64_t)0 && (q & ~mask) != 0)) { 3554 if (hflag) 3555 /* integer overflow detected, op '%s' */ 3556 warning(141, op_name(tn->tn_op)); 3557 } 3558 3559 v->v_quad = convert_integer(q, t, 0); 3560 3561 cn = build_constant(tn->tn_type, v); 3562 if (tn->tn_left->tn_system_dependent) 3563 cn->tn_system_dependent = true; 3564 if (is_binary(tn) && tn->tn_right->tn_system_dependent) 3565 cn->tn_system_dependent = true; 3566 3567 return cn; 3568 } 3569 3570 /* 3571 * Fold constant nodes, as much as is needed for comparing the value with 0. 3572 */ 3573 static tnode_t * 3574 fold_bool(tnode_t *tn) 3575 { 3576 bool l, r; 3577 val_t *v; 3578 3579 v = xcalloc(1, sizeof(*v)); 3580 v->v_tspec = tn->tn_type->t_tspec; 3581 lint_assert(v->v_tspec == INT || (Tflag && v->v_tspec == BOOL)); 3582 3583 l = constant_is_nonzero(tn->tn_left); 3584 r = is_binary(tn) && constant_is_nonzero(tn->tn_right); 3585 3586 switch (tn->tn_op) { 3587 case NOT: 3588 if (hflag && !constcond_flag) 3589 /* constant argument to '!' */ 3590 warning(239); 3591 v->v_quad = !l ? 1 : 0; 3592 break; 3593 case LOGAND: 3594 v->v_quad = l && r ? 1 : 0; 3595 break; 3596 case LOGOR: 3597 v->v_quad = l || r ? 1 : 0; 3598 break; 3599 default: 3600 lint_assert(/*CONSTCOND*/false); 3601 } 3602 3603 return build_constant(tn->tn_type, v); 3604 } 3605 3606 static ldbl_t 3607 floating_error_value(tspec_t t, ldbl_t lv) 3608 { 3609 if (t == FLOAT) { 3610 return lv < 0 ? -FLT_MAX : FLT_MAX; 3611 } else if (t == DOUBLE) { 3612 return lv < 0 ? -DBL_MAX : DBL_MAX; 3613 } else { 3614 /* LINTED 248: floating-point constant out of range */ 3615 ldbl_t max = LDBL_MAX; 3616 return lv < 0 ? -max : max; 3617 } 3618 } 3619 3620 /* 3621 * Fold constant nodes having operands with floating point type. 3622 */ 3623 static tnode_t * 3624 fold_float(tnode_t *tn) 3625 { 3626 val_t *v; 3627 tspec_t t; 3628 ldbl_t lv, rv = 0; 3629 3630 fpe = 0; 3631 v = xcalloc(1, sizeof(*v)); 3632 v->v_tspec = t = tn->tn_type->t_tspec; 3633 3634 lint_assert(is_floating(t)); 3635 lint_assert(t == tn->tn_left->tn_type->t_tspec); 3636 lint_assert(!is_binary(tn) || t == tn->tn_right->tn_type->t_tspec); 3637 3638 lv = tn->tn_left->tn_val->v_ldbl; 3639 if (is_binary(tn)) 3640 rv = tn->tn_right->tn_val->v_ldbl; 3641 3642 switch (tn->tn_op) { 3643 case UPLUS: 3644 v->v_ldbl = lv; 3645 break; 3646 case UMINUS: 3647 v->v_ldbl = -lv; 3648 break; 3649 case MULT: 3650 v->v_ldbl = lv * rv; 3651 break; 3652 case DIV: 3653 if (rv == 0.0) { 3654 /* division by 0 */ 3655 error(139); 3656 v->v_ldbl = floating_error_value(t, lv); 3657 } else { 3658 v->v_ldbl = lv / rv; 3659 } 3660 break; 3661 case PLUS: 3662 v->v_ldbl = lv + rv; 3663 break; 3664 case MINUS: 3665 v->v_ldbl = lv - rv; 3666 break; 3667 case LT: 3668 v->v_quad = lv < rv ? 1 : 0; 3669 break; 3670 case LE: 3671 v->v_quad = lv <= rv ? 1 : 0; 3672 break; 3673 case GE: 3674 v->v_quad = lv >= rv ? 1 : 0; 3675 break; 3676 case GT: 3677 v->v_quad = lv > rv ? 1 : 0; 3678 break; 3679 case EQ: 3680 v->v_quad = lv == rv ? 1 : 0; 3681 break; 3682 case NE: 3683 v->v_quad = lv != rv ? 1 : 0; 3684 break; 3685 default: 3686 lint_assert(/*CONSTCOND*/false); 3687 } 3688 3689 lint_assert(fpe != 0 || isnan((double)v->v_ldbl) == 0); 3690 if (fpe != 0 || isfinite((double)v->v_ldbl) == 0 || 3691 (t == FLOAT && 3692 (v->v_ldbl > FLT_MAX || v->v_ldbl < -FLT_MAX)) || 3693 (t == DOUBLE && 3694 (v->v_ldbl > DBL_MAX || v->v_ldbl < -DBL_MAX))) { 3695 /* floating point overflow on operator '%s' */ 3696 warning(142, op_name(tn->tn_op)); 3697 v->v_ldbl = floating_error_value(t, v->v_ldbl); 3698 fpe = 0; 3699 } 3700 3701 return build_constant(tn->tn_type, v); 3702 } 3703 3704 3705 /* 3706 * Create a constant node for sizeof. 3707 */ 3708 tnode_t * 3709 build_sizeof(const type_t *tp) 3710 { 3711 unsigned int size_in_bytes = type_size_in_bits(tp) / CHAR_SIZE; 3712 tnode_t *tn = build_integer_constant(SIZEOF_TSPEC, size_in_bytes); 3713 tn->tn_system_dependent = true; 3714 debug_step("build_sizeof '%s' = %u", type_name(tp), size_in_bytes); 3715 return tn; 3716 } 3717 3718 /* 3719 * Create a constant node for offsetof. 3720 */ 3721 /* ARGSUSED */ /* See implementation comments. */ 3722 tnode_t * 3723 build_offsetof(const type_t *tp, const sym_t *sym) 3724 { 3725 unsigned int offset_in_bytes; 3726 tnode_t *tn; 3727 3728 if (!is_struct_or_union(tp->t_tspec)) 3729 /* unacceptable operand of '%s' */ 3730 error(111, "offsetof"); 3731 3732 /* XXX: wrong size, no checking for sym fixme */ 3733 offset_in_bytes = type_size_in_bits(tp) / CHAR_SIZE; 3734 tn = build_integer_constant(SIZEOF_TSPEC, offset_in_bytes); 3735 tn->tn_system_dependent = true; 3736 return tn; 3737 } 3738 3739 unsigned int 3740 type_size_in_bits(const type_t *tp) 3741 { 3742 unsigned int elem, elsz; 3743 bool flex; 3744 3745 elem = 1; 3746 flex = false; 3747 lint_assert(tp != NULL); 3748 while (tp->t_tspec == ARRAY) { 3749 flex = true; /* allow c99 flex arrays [] [0] */ 3750 elem *= tp->t_dim; 3751 tp = tp->t_subt; 3752 } 3753 if (elem == 0) { 3754 if (!flex) { 3755 /* cannot take size/alignment of incomplete type */ 3756 error(143); 3757 elem = 1; 3758 } 3759 } 3760 switch (tp->t_tspec) { 3761 case FUNC: 3762 /* cannot take size/alignment of function type '%s' */ 3763 error(144, type_name(tp)); 3764 elsz = 1; 3765 break; 3766 case STRUCT: 3767 case UNION: 3768 if (is_incomplete(tp)) { 3769 /* cannot take size/alignment of incomplete type */ 3770 error(143); 3771 elsz = 1; 3772 } else { 3773 elsz = tp->t_str->sou_size_in_bits; 3774 } 3775 break; 3776 case ENUM: 3777 if (is_incomplete(tp)) { 3778 /* cannot take size/alignment of incomplete type */ 3779 warning(143); 3780 } 3781 /* FALLTHROUGH */ 3782 default: 3783 if (tp->t_bitfield) { 3784 /* cannot take size/alignment of bit-field */ 3785 error(145); 3786 } 3787 if (tp->t_tspec == VOID) { 3788 /* cannot take size/alignment of void */ 3789 error(146); 3790 elsz = 1; 3791 } else { 3792 elsz = size_in_bits(tp->t_tspec); 3793 lint_assert(elsz > 0); 3794 } 3795 break; 3796 } 3797 3798 return elem * elsz; 3799 } 3800 3801 tnode_t * 3802 build_alignof(const type_t *tp) 3803 { 3804 switch (tp->t_tspec) { 3805 case ARRAY: 3806 break; 3807 3808 case FUNC: 3809 /* cannot take size/alignment of function type '%s' */ 3810 error(144, type_name(tp)); 3811 return 0; 3812 3813 case STRUCT: 3814 case UNION: 3815 if (is_incomplete(tp)) { 3816 /* cannot take size/alignment of incomplete type */ 3817 error(143); 3818 return 0; 3819 } 3820 break; 3821 case ENUM: 3822 break; 3823 default: 3824 if (tp->t_bitfield) { 3825 /* cannot take size/alignment of bit-field */ 3826 error(145); 3827 return 0; 3828 } 3829 if (tp->t_tspec == VOID) { 3830 /* cannot take size/alignment of void */ 3831 error(146); 3832 return 0; 3833 } 3834 break; 3835 } 3836 3837 return build_integer_constant(SIZEOF_TSPEC, 3838 (int64_t)alignment_in_bits(tp) / CHAR_SIZE); 3839 } 3840 3841 /* 3842 * Type casts. 3843 */ 3844 tnode_t * 3845 cast(tnode_t *tn, type_t *tp) 3846 { 3847 tspec_t nt, ot; 3848 3849 if (tn == NULL) 3850 return NULL; 3851 3852 tn = cconv(tn); 3853 3854 lint_assert(tp != NULL); 3855 nt = tp->t_tspec; 3856 ot = tn->tn_type->t_tspec; 3857 3858 if (nt == VOID) { 3859 /* 3860 * C90 6.3.4, C99 6.5.4p2 and C11 6.5.4p2 allow any type to 3861 * be cast to void. The only other allowed casts are from a 3862 * scalar type to a scalar type. 3863 */ 3864 } else if (nt == UNION) { 3865 sym_t *m; 3866 struct_or_union *str = tp->t_str; 3867 if (!allow_gcc) { 3868 /* union cast is a GCC extension */ 3869 error(328); 3870 return NULL; 3871 } 3872 for (m = str->sou_first_member; m != NULL; m = m->s_next) { 3873 if (eqtype(m->s_type, tn->tn_type, 3874 false, false, NULL)) { 3875 tn = expr_alloc_tnode(); 3876 tn->tn_op = CVT; 3877 tn->tn_type = tp; 3878 tn->tn_cast = true; 3879 tn->tn_right = NULL; 3880 return tn; 3881 } 3882 } 3883 /* type '%s' is not a member of '%s' */ 3884 error(329, type_name(tn->tn_type), type_name(tp)); 3885 return NULL; 3886 } else if (nt == STRUCT || nt == ARRAY || nt == FUNC) { 3887 /* Casting to a struct is an undocumented GCC extension. */ 3888 if (!(allow_gcc && nt == STRUCT)) 3889 goto invalid_cast; 3890 } else if (is_struct_or_union(ot)) { 3891 goto invalid_cast; 3892 } else if (ot == VOID) { 3893 /* improper cast of void expression */ 3894 error(148); 3895 return NULL; 3896 } else if (is_integer(nt) && is_scalar(ot)) { 3897 /* ok */ 3898 } else if (is_floating(nt) && is_arithmetic(ot)) { 3899 /* ok */ 3900 } else if (nt == PTR && is_integer(ot)) { 3901 /* ok */ 3902 } else if (nt == PTR && ot == PTR) { 3903 if (!tp->t_subt->t_const && tn->tn_type->t_subt->t_const) { 3904 if (hflag) 3905 /* cast discards 'const' from type '%s' */ 3906 warning(275, type_name(tn->tn_type)); 3907 } 3908 } else 3909 goto invalid_cast; 3910 3911 tn = convert(CVT, 0, tp, tn); 3912 tn->tn_cast = true; 3913 3914 return tn; 3915 3916 invalid_cast: 3917 /* invalid cast from '%s' to '%s' */ 3918 error(147, type_name(tn->tn_type), type_name(tp)); 3919 return NULL; 3920 } 3921 3922 /* 3923 * Create the node for a function argument. 3924 * All necessary conversions and type checks are done in 3925 * build_function_call because build_function_argument has no 3926 * information about expected argument types. 3927 */ 3928 tnode_t * 3929 build_function_argument(tnode_t *args, tnode_t *arg) 3930 { 3931 tnode_t *ntn; 3932 3933 /* 3934 * If there was a serious error in the expression for the argument, 3935 * create a dummy argument so the positions of the remaining arguments 3936 * will not change. 3937 */ 3938 if (arg == NULL) 3939 arg = build_integer_constant(INT, 0); 3940 3941 ntn = new_tnode(PUSH, arg->tn_sys, arg->tn_type, arg, args); 3942 3943 return ntn; 3944 } 3945 3946 /* 3947 * Create the node for a function call. Also check types of 3948 * function arguments and insert conversions, if necessary. 3949 */ 3950 tnode_t * 3951 build_function_call(tnode_t *func, bool sys, tnode_t *args) 3952 { 3953 tnode_t *ntn; 3954 op_t fcop; 3955 3956 if (func == NULL) 3957 return NULL; 3958 3959 if (func->tn_op == NAME && func->tn_type->t_tspec == FUNC) { 3960 fcop = CALL; 3961 } else { 3962 fcop = ICALL; 3963 } 3964 3965 check_ctype_function_call(func, args); 3966 3967 /* 3968 * after cconv() func will always be a pointer to a function 3969 * if it is a valid function designator. 3970 */ 3971 func = cconv(func); 3972 3973 if (func->tn_type->t_tspec != PTR || 3974 func->tn_type->t_subt->t_tspec != FUNC) { 3975 /* cannot call '%s', must be a function */ 3976 error(149, type_name(func->tn_type)); 3977 return NULL; 3978 } 3979 3980 args = check_function_arguments(func->tn_type->t_subt, args); 3981 3982 ntn = new_tnode(fcop, sys, func->tn_type->t_subt->t_subt, func, args); 3983 3984 return ntn; 3985 } 3986 3987 /* 3988 * Check types of all function arguments and insert conversions, 3989 * if necessary. 3990 */ 3991 static tnode_t * 3992 check_function_arguments(type_t *ftp, tnode_t *args) 3993 { 3994 tnode_t *arg; 3995 sym_t *asym; 3996 tspec_t at; 3997 int narg, npar, n, i; 3998 3999 /* get # of args in the prototype */ 4000 npar = 0; 4001 for (asym = ftp->t_args; asym != NULL; asym = asym->s_next) 4002 npar++; 4003 4004 /* get # of args in function call */ 4005 narg = 0; 4006 for (arg = args; arg != NULL; arg = arg->tn_right) 4007 narg++; 4008 4009 asym = ftp->t_args; 4010 if (ftp->t_proto && npar != narg && !(ftp->t_vararg && npar < narg)) { 4011 /* argument mismatch: %d %s passed, %d expected */ 4012 error(150, narg, narg > 1 ? "arguments" : "argument", npar); 4013 asym = NULL; 4014 } 4015 4016 for (n = 1; n <= narg; n++) { 4017 4018 /* 4019 * The rightmost argument is at the top of the argument 4020 * subtree. 4021 */ 4022 for (i = narg, arg = args; i > n; i--, arg = arg->tn_right) 4023 continue; 4024 4025 /* some things which are always not allowed */ 4026 if ((at = arg->tn_left->tn_type->t_tspec) == VOID) { 4027 /* void expressions may not be arguments, arg #%d */ 4028 error(151, n); 4029 return NULL; 4030 } else if (is_struct_or_union(at) && 4031 is_incomplete(arg->tn_left->tn_type)) { 4032 /* argument cannot have unknown size, arg #%d */ 4033 error(152, n); 4034 return NULL; 4035 } else if (is_integer(at) && 4036 arg->tn_left->tn_type->t_is_enum && 4037 is_incomplete(arg->tn_left->tn_type)) { 4038 /* argument cannot have unknown size, arg #%d */ 4039 warning(152, n); 4040 } 4041 4042 /* class conversions (arg in value context) */ 4043 arg->tn_left = cconv(arg->tn_left); 4044 4045 if (asym != NULL) { 4046 arg->tn_left = check_prototype_argument( 4047 n, asym->s_type, arg->tn_left); 4048 } else { 4049 arg->tn_left = promote(NOOP, true, arg->tn_left); 4050 } 4051 arg->tn_type = arg->tn_left->tn_type; 4052 4053 if (asym != NULL) 4054 asym = asym->s_next; 4055 } 4056 4057 return args; 4058 } 4059 4060 /* 4061 * Compare the type of an argument with the corresponding type of a 4062 * prototype parameter. If it is a valid combination, but both types 4063 * are not the same, insert a conversion to convert the argument into 4064 * the type of the parameter. 4065 */ 4066 static tnode_t * 4067 check_prototype_argument( 4068 int n, /* pos of arg */ 4069 type_t *tp, /* expected type (from prototype) */ 4070 tnode_t *tn) /* argument */ 4071 { 4072 tnode_t *ln; 4073 bool dowarn; 4074 4075 ln = xcalloc(1, sizeof(*ln)); 4076 ln->tn_type = expr_unqualified_type(tp); 4077 ln->tn_lvalue = true; 4078 if (typeok(FARG, n, ln, tn)) { 4079 if (!eqtype(tp, tn->tn_type, 4080 true, false, (dowarn = false, &dowarn)) || dowarn) 4081 tn = convert(FARG, n, tp, tn); 4082 } 4083 free(ln); 4084 return tn; 4085 } 4086 4087 /* 4088 * Return the value of an integral constant expression. 4089 * If the expression is not constant or its type is not an integer 4090 * type, an error message is printed. 4091 */ 4092 val_t * 4093 constant(tnode_t *tn, bool required) 4094 { 4095 val_t *v; 4096 4097 if (tn != NULL) 4098 tn = cconv(tn); 4099 if (tn != NULL) 4100 tn = promote(NOOP, false, tn); 4101 4102 v = xcalloc(1, sizeof(*v)); 4103 4104 if (tn == NULL) { 4105 lint_assert(nerr != 0); 4106 debug_step("constant node is null; returning 1 instead"); 4107 v->v_tspec = INT; 4108 v->v_quad = 1; 4109 return v; 4110 } 4111 4112 v->v_tspec = tn->tn_type->t_tspec; 4113 4114 if (tn->tn_op == CON) { 4115 lint_assert(tn->tn_type->t_tspec == tn->tn_val->v_tspec); 4116 if (is_integer(tn->tn_val->v_tspec)) { 4117 v->v_unsigned_since_c90 = 4118 tn->tn_val->v_unsigned_since_c90; 4119 v->v_quad = tn->tn_val->v_quad; 4120 return v; 4121 } 4122 v->v_quad = tn->tn_val->v_ldbl; 4123 } else { 4124 v->v_quad = 1; 4125 } 4126 4127 if (required) 4128 /* integral constant expression expected */ 4129 error(55); 4130 else 4131 /* variable array dimension is a C99/GCC extension */ 4132 c99ism(318); 4133 4134 if (!is_integer(v->v_tspec)) 4135 v->v_tspec = INT; 4136 4137 return v; 4138 } 4139 4140 static bool 4141 is_constcond_false(const tnode_t *tn, tspec_t t) 4142 { 4143 return (t == BOOL || t == INT) && 4144 tn->tn_op == CON && tn->tn_val->v_quad == 0; 4145 } 4146 4147 /* 4148 * Perform some tests on expressions which can't be done in build_binary() 4149 * and functions called by build_binary(). These tests must be done here 4150 * because we need some information about the context in which the operations 4151 * are performed. 4152 * After all tests are performed and dofreeblk is true, expr() frees the 4153 * memory which is used for the expression. 4154 */ 4155 void 4156 expr(tnode_t *tn, bool vctx, bool cond, bool dofreeblk, bool is_do_while) 4157 { 4158 4159 if (tn == NULL) { /* in case of errors */ 4160 expr_free_all(); 4161 return; 4162 } 4163 4164 /* expr() is also called in global initializations */ 4165 if (dcs->d_kind != DK_EXTERN && !is_do_while) 4166 check_statement_reachable(); 4167 4168 check_expr_misc(tn, vctx, cond, !cond, false, false, false); 4169 if (tn->tn_op == ASSIGN) { 4170 if (hflag && cond) 4171 /* assignment in conditional context */ 4172 warning(159); 4173 } else if (tn->tn_op == CON) { 4174 if (hflag && cond && !constcond_flag && 4175 !tn->tn_system_dependent && 4176 !(is_do_while && 4177 is_constcond_false(tn, tn->tn_type->t_tspec))) 4178 /* constant in conditional context */ 4179 warning(161); 4180 } 4181 if (!modtab[tn->tn_op].m_has_side_effect) { 4182 /* 4183 * for left operands of COMMA this warning is already 4184 * printed 4185 */ 4186 if (tn->tn_op != COMMA && !vctx && !cond) 4187 check_null_effect(tn); 4188 } 4189 debug_node(tn); 4190 4191 /* free the tree memory */ 4192 if (dofreeblk) 4193 expr_free_all(); 4194 } 4195 4196 static bool 4197 has_side_effect(const tnode_t *tn) /* NOLINT(misc-no-recursion) */ 4198 { 4199 op_t op = tn->tn_op; 4200 4201 if (modtab[op].m_has_side_effect) 4202 return true; 4203 4204 if (op == CVT && tn->tn_type->t_tspec == VOID) 4205 return has_side_effect(tn->tn_left); 4206 4207 /* XXX: Why not has_side_effect(tn->tn_left) as well? */ 4208 if (op == LOGAND || op == LOGOR) 4209 return has_side_effect(tn->tn_right); 4210 4211 /* XXX: Why not has_side_effect(tn->tn_left) as well? */ 4212 if (op == QUEST) 4213 return has_side_effect(tn->tn_right); 4214 4215 if (op == COLON || op == COMMA) { 4216 return has_side_effect(tn->tn_left) || 4217 has_side_effect(tn->tn_right); 4218 } 4219 4220 return false; 4221 } 4222 4223 static bool 4224 is_void_cast(const tnode_t *tn) 4225 { 4226 4227 return tn->tn_op == CVT && tn->tn_cast && 4228 tn->tn_type->t_tspec == VOID; 4229 } 4230 4231 static bool 4232 is_local_symbol(const tnode_t *tn) 4233 { 4234 4235 return tn->tn_op == LOAD && 4236 tn->tn_left->tn_op == NAME && 4237 tn->tn_left->tn_sym->s_scl == AUTO; 4238 } 4239 4240 static bool 4241 is_int_constant_zero(const tnode_t *tn) 4242 { 4243 4244 return tn->tn_op == CON && 4245 tn->tn_type->t_tspec == INT && 4246 tn->tn_val->v_quad == 0; 4247 } 4248 4249 static void 4250 check_null_effect(const tnode_t *tn) 4251 { 4252 4253 if (!hflag) 4254 return; 4255 if (has_side_effect(tn)) 4256 return; 4257 if (is_void_cast(tn) && is_local_symbol(tn->tn_left)) 4258 return; 4259 if (is_void_cast(tn) && is_int_constant_zero(tn->tn_left)) 4260 return; 4261 4262 /* expression has null effect */ 4263 warning(129); 4264 } 4265 4266 static void 4267 check_expr_addr(const tnode_t *ln, bool szof, bool fcall) 4268 { 4269 /* XXX: Taking warn_about_unreachable into account here feels wrong. */ 4270 if (ln->tn_op == NAME && (reached || !warn_about_unreachable)) { 4271 if (!szof) 4272 mark_as_set(ln->tn_sym); 4273 mark_as_used(ln->tn_sym, fcall, szof); 4274 } 4275 if (ln->tn_op == INDIR && ln->tn_left->tn_op == PLUS) 4276 /* check the range of array indices */ 4277 check_array_index(ln->tn_left, true); 4278 } 4279 4280 static void 4281 check_expr_load(const tnode_t *ln) 4282 { 4283 if (ln->tn_op == INDIR && ln->tn_left->tn_op == PLUS) 4284 /* check the range of array indices */ 4285 check_array_index(ln->tn_left, false); 4286 } 4287 4288 static void 4289 check_expr_side_effect(const tnode_t *ln, bool szof) 4290 { 4291 scl_t sc; 4292 dinfo_t *di; 4293 4294 /* XXX: Taking warn_about_unreachable into account here feels wrong. */ 4295 if (ln->tn_op == NAME && (reached || !warn_about_unreachable)) { 4296 sc = ln->tn_sym->s_scl; 4297 /* 4298 * Look if there was a asm statement in one of the 4299 * compound statements we are in. If not, we don't 4300 * print a warning. 4301 */ 4302 for (di = dcs; di != NULL; di = di->d_enclosing) { 4303 if (di->d_asm) 4304 break; 4305 } 4306 if (sc != EXTERN && sc != STATIC && 4307 !ln->tn_sym->s_set && !szof && di == NULL) { 4308 /* '%s' may be used before set */ 4309 warning(158, ln->tn_sym->s_name); 4310 mark_as_set(ln->tn_sym); 4311 } 4312 mark_as_used(ln->tn_sym, false, false); 4313 } 4314 } 4315 4316 static void 4317 check_expr_assign(const tnode_t *ln, bool szof) 4318 { 4319 /* XXX: Taking warn_about_unreachable into account here feels wrong. */ 4320 if (ln->tn_op == NAME && !szof && (reached || !warn_about_unreachable)) { 4321 mark_as_set(ln->tn_sym); 4322 if (ln->tn_sym->s_scl == EXTERN) 4323 outusg(ln->tn_sym); 4324 } 4325 if (ln->tn_op == INDIR && ln->tn_left->tn_op == PLUS) 4326 /* check the range of array indices */ 4327 check_array_index(ln->tn_left, false); 4328 } 4329 4330 static void 4331 check_expr_call(const tnode_t *tn, const tnode_t *ln, 4332 bool szof, bool vctx, bool cond, bool retval_discarded) 4333 { 4334 lint_assert(ln->tn_op == ADDR); 4335 lint_assert(ln->tn_left->tn_op == NAME); 4336 if (!szof && 4337 !is_compiler_builtin(ln->tn_left->tn_sym->s_name)) 4338 outcall(tn, vctx || cond, retval_discarded); 4339 } 4340 4341 static bool 4342 check_expr_op(const tnode_t *tn, op_t op, const tnode_t *ln, 4343 bool szof, bool fcall, bool vctx, bool cond, 4344 bool retval_discarded, bool eqwarn) 4345 { 4346 switch (op) { 4347 case ADDR: 4348 check_expr_addr(ln, szof, fcall); 4349 break; 4350 case LOAD: 4351 check_expr_load(ln); 4352 /* FALLTHROUGH */ 4353 case PUSH: 4354 case INCBEF: 4355 case DECBEF: 4356 case INCAFT: 4357 case DECAFT: 4358 case ADDASS: 4359 case SUBASS: 4360 case MULASS: 4361 case DIVASS: 4362 case MODASS: 4363 case ANDASS: 4364 case ORASS: 4365 case XORASS: 4366 case SHLASS: 4367 case SHRASS: 4368 case REAL: 4369 case IMAG: 4370 check_expr_side_effect(ln, szof); 4371 break; 4372 case ASSIGN: 4373 check_expr_assign(ln, szof); 4374 break; 4375 case CALL: 4376 check_expr_call(tn, ln, szof, vctx, cond, retval_discarded); 4377 break; 4378 case EQ: 4379 if (hflag && eqwarn) 4380 /* operator '==' found where '=' was expected */ 4381 warning(160); 4382 break; 4383 case CON: 4384 case NAME: 4385 case STRING: 4386 return false; 4387 default: 4388 break; 4389 } 4390 return true; 4391 } 4392 4393 /* 4394 * vctx ??? 4395 * cond whether the expression is a condition that 4396 * will be compared with 0 4397 * eqwarn whether the operator '==' might be a 4398 * misspelled '=' 4399 * fcall whether the expression is a function call 4400 * retval_discarded whether the return value of a function call 4401 * is discarded; such calls will be analyzed by 4402 * lint2 in messages 4, 8 and 9 4403 * szof whether the expression is part of a sizeof 4404 * expression, which means that its value is 4405 * discarded since only the type is relevant 4406 */ 4407 void 4408 check_expr_misc(const tnode_t *tn, bool vctx, bool cond, 4409 bool eqwarn, bool fcall, bool retval_discarded, bool szof) 4410 { 4411 tnode_t *ln, *rn; 4412 const mod_t *mp; 4413 op_t op; 4414 bool cvctx, ccond, eq, discard; 4415 4416 if (tn == NULL) 4417 return; 4418 4419 ln = tn->tn_left; 4420 rn = tn->tn_right; 4421 mp = &modtab[op = tn->tn_op]; 4422 4423 if (!check_expr_op(tn, op, ln, 4424 szof, fcall, vctx, cond, retval_discarded, eqwarn)) 4425 return; 4426 4427 cvctx = mp->m_value_context; 4428 ccond = mp->m_compares_with_zero; 4429 eq = mp->m_warn_if_operand_eq && 4430 !ln->tn_parenthesized && 4431 rn != NULL && !rn->tn_parenthesized; 4432 4433 /* 4434 * values of operands of ':' are not used if the type of at least 4435 * one of the operands (for gcc compatibility) is void 4436 * XXX test/value context of QUEST should probably be used as 4437 * context for both operands of COLON 4438 */ 4439 if (op == COLON && tn->tn_type->t_tspec == VOID) 4440 cvctx = ccond = false; 4441 discard = op == CVT && tn->tn_type->t_tspec == VOID; 4442 check_expr_misc(ln, cvctx, ccond, eq, op == CALL, discard, szof); 4443 4444 switch (op) { 4445 case PUSH: 4446 if (rn != NULL) 4447 check_expr_misc(rn, false, false, eq, false, false, 4448 szof); 4449 break; 4450 case LOGAND: 4451 case LOGOR: 4452 check_expr_misc(rn, false, true, eq, false, false, szof); 4453 break; 4454 case COLON: 4455 check_expr_misc(rn, cvctx, ccond, eq, false, false, szof); 4456 break; 4457 case COMMA: 4458 check_expr_misc(rn, vctx, cond, false, false, false, szof); 4459 break; 4460 default: 4461 if (mp->m_binary) 4462 check_expr_misc(rn, true, false, eq, false, false, 4463 szof); 4464 break; 4465 } 4466 } 4467 4468 /* 4469 * Checks the range of array indices, if possible. 4470 * amper is set if only the address of the element is used. This 4471 * means that the index is allowed to refer to the first element 4472 * after the array. 4473 */ 4474 static void 4475 check_array_index(tnode_t *tn, bool amper) 4476 { 4477 int dim; 4478 tnode_t *ln, *rn; 4479 int elsz; 4480 int64_t con; 4481 4482 ln = tn->tn_left; 4483 rn = tn->tn_right; 4484 4485 /* We can only check constant indices. */ 4486 if (rn->tn_op != CON) 4487 return; 4488 4489 /* Return if the left node does not stem from an array. */ 4490 if (ln->tn_op != ADDR) 4491 return; 4492 if (ln->tn_left->tn_op != STRING && ln->tn_left->tn_op != NAME) 4493 return; 4494 if (ln->tn_left->tn_type->t_tspec != ARRAY) 4495 return; 4496 4497 /* 4498 * For incomplete array types, we can print a warning only if 4499 * the index is negative. 4500 */ 4501 if (is_incomplete(ln->tn_left->tn_type) && rn->tn_val->v_quad >= 0) 4502 return; 4503 4504 /* Get the size of one array element */ 4505 if ((elsz = length_in_bits(ln->tn_type->t_subt, NULL)) == 0) 4506 return; 4507 elsz /= CHAR_SIZE; 4508 4509 /* Change the unit of the index from bytes to element size. */ 4510 if (is_uinteger(rn->tn_type->t_tspec)) { 4511 con = (uint64_t)rn->tn_val->v_quad / elsz; 4512 } else { 4513 con = rn->tn_val->v_quad / elsz; 4514 } 4515 4516 dim = ln->tn_left->tn_type->t_dim + (amper ? 1 : 0); 4517 4518 if (!is_uinteger(rn->tn_type->t_tspec) && con < 0) { 4519 /* array subscript cannot be negative: %ld */ 4520 warning(167, (long)con); 4521 } else if (dim > 0 && (uint64_t)con >= (uint64_t)dim) { 4522 /* array subscript cannot be > %d: %ld */ 4523 warning(168, dim - 1, (long)con); 4524 } 4525 } 4526 4527 static bool 4528 is_out_of_char_range(const tnode_t *tn) 4529 { 4530 return tn->tn_op == CON && 4531 !(0 <= tn->tn_val->v_quad && 4532 tn->tn_val->v_quad < 1 << (CHAR_SIZE - 1)); 4533 } 4534 4535 /* 4536 * Check for ordered comparisons of unsigned values with 0. 4537 */ 4538 static void 4539 check_integer_comparison(op_t op, tnode_t *ln, tnode_t *rn) 4540 { 4541 tspec_t lt, rt; 4542 4543 lt = ln->tn_type->t_tspec; 4544 rt = rn->tn_type->t_tspec; 4545 4546 if (ln->tn_op != CON && rn->tn_op != CON) 4547 return; 4548 4549 if (!is_integer(lt) || !is_integer(rt)) 4550 return; 4551 4552 if (hflag || pflag) { 4553 if (lt == CHAR && is_out_of_char_range(rn)) { 4554 /* nonportable character comparison '%s %d' */ 4555 warning(230, op_name(op), (int)rn->tn_val->v_quad); 4556 return; 4557 } 4558 if (rt == CHAR && is_out_of_char_range(ln)) { 4559 /* nonportable character comparison '%s %d' */ 4560 warning(230, op_name(op), (int)ln->tn_val->v_quad); 4561 return; 4562 } 4563 } 4564 4565 if (is_uinteger(lt) && !is_uinteger(rt) && 4566 rn->tn_op == CON && rn->tn_val->v_quad <= 0) { 4567 if (rn->tn_val->v_quad < 0) { 4568 /* operator '%s' compares '%s' with '%s' */ 4569 warning(162, op_name(op), 4570 type_name(ln->tn_type), "negative constant"); 4571 } else if (op == LT || op == GE) { 4572 /* operator '%s' compares '%s' with '%s' */ 4573 warning(162, op_name(op), type_name(ln->tn_type), "0"); 4574 } 4575 return; 4576 } 4577 if (is_uinteger(rt) && !is_uinteger(lt) && 4578 ln->tn_op == CON && ln->tn_val->v_quad <= 0) { 4579 if (ln->tn_val->v_quad < 0) { 4580 /* operator '%s' compares '%s' with '%s' */ 4581 warning(162, op_name(op), 4582 "negative constant", type_name(rn->tn_type)); 4583 } else if (op == GT || op == LE) { 4584 /* operator '%s' compares '%s' with '%s' */ 4585 warning(162, op_name(op), "0", type_name(rn->tn_type)); 4586 } 4587 return; 4588 } 4589 } 4590 4591 /* 4592 * Return whether the expression can be used for static initialization. 4593 * 4594 * Constant initialization expressions must be constant or an address 4595 * of a static object with an optional offset. In the first case, 4596 * the result is returned in *offsp. In the second case, the static 4597 * object is returned in *symp and the offset in *offsp. 4598 * 4599 * The expression can consist of PLUS, MINUS, ADDR, NAME, STRING and 4600 * CON. Type conversions are allowed if they do not change binary 4601 * representation (including width). 4602 * 4603 * C99 6.6 "Constant expressions" 4604 * C99 6.7.8p4 restricts initializers for static storage duration 4605 */ 4606 bool 4607 constant_addr(const tnode_t *tn, const sym_t **symp, ptrdiff_t *offsp) 4608 { 4609 const sym_t *sym; 4610 ptrdiff_t offs1, offs2; 4611 tspec_t t, ot; 4612 4613 switch (tn->tn_op) { 4614 case MINUS: 4615 if (tn->tn_right->tn_op == CVT) 4616 return constant_addr(tn->tn_right, symp, offsp); 4617 else if (tn->tn_right->tn_op != CON) 4618 return false; 4619 /* FALLTHROUGH */ 4620 case PLUS: 4621 offs1 = offs2 = 0; 4622 if (tn->tn_left->tn_op == CON) { 4623 offs1 = (ptrdiff_t)tn->tn_left->tn_val->v_quad; 4624 if (!constant_addr(tn->tn_right, &sym, &offs2)) 4625 return false; 4626 } else if (tn->tn_right->tn_op == CON) { 4627 offs2 = (ptrdiff_t)tn->tn_right->tn_val->v_quad; 4628 if (tn->tn_op == MINUS) 4629 offs2 = -offs2; 4630 if (!constant_addr(tn->tn_left, &sym, &offs1)) 4631 return false; 4632 } else { 4633 return false; 4634 } 4635 *symp = sym; 4636 *offsp = offs1 + offs2; 4637 return true; 4638 case ADDR: 4639 if (tn->tn_left->tn_op == NAME) { 4640 *symp = tn->tn_left->tn_sym; 4641 *offsp = 0; 4642 return true; 4643 } else { 4644 /* 4645 * If this would be the front end of a compiler we 4646 * would return a label instead of 0, at least if 4647 * 'tn->tn_left->tn_op == STRING'. 4648 */ 4649 *symp = NULL; 4650 *offsp = 0; 4651 return true; 4652 } 4653 case CVT: 4654 t = tn->tn_type->t_tspec; 4655 ot = tn->tn_left->tn_type->t_tspec; 4656 if ((!is_integer(t) && t != PTR) || 4657 (!is_integer(ot) && ot != PTR)) { 4658 return false; 4659 } 4660 #if 0 4661 /* 4662 * consider: 4663 * struct foo { 4664 * unsigned char a; 4665 * } f = { 4666 * (unsigned char)(unsigned long) 4667 * (&(((struct foo *)0)->a)) 4668 * }; 4669 * since psize(unsigned long) != psize(unsigned char), 4670 * this fails. 4671 */ 4672 else if (psize(t) != psize(ot)) 4673 return -1; 4674 #endif 4675 return constant_addr(tn->tn_left, symp, offsp); 4676 default: 4677 return false; 4678 } 4679 } 4680 4681 /* Append s2 to s1, then free s2. */ 4682 strg_t * 4683 cat_strings(strg_t *s1, strg_t *s2) 4684 { 4685 4686 if (s1->st_char != s2->st_char) { 4687 /* cannot concatenate wide and regular string literals */ 4688 error(292); 4689 return s1; 4690 } 4691 4692 size_t len1 = s1->st_len; 4693 size_t len2 = s2->st_len; 4694 size_t chsize = s1->st_char ? sizeof(char) : sizeof(wchar_t); 4695 size_t size1 = len1 * chsize; 4696 size_t size2 = (len2 + 1) * chsize; 4697 s1->st_mem = xrealloc(s1->st_mem, size1 + size2); 4698 memcpy((char *)s1->st_mem + size1, s2->st_mem, size2); 4699 free(s2->st_mem); 4700 4701 s1->st_len = len1 + len2; 4702 free(s2); 4703 4704 return s1; 4705 } 4706 4707 static bool 4708 is_confusing_precedence(op_t op, op_t lop, bool lparen, op_t rop, bool rparen) 4709 { 4710 4711 if (op == SHL || op == SHR) { 4712 if (!lparen && (lop == PLUS || lop == MINUS)) 4713 return true; 4714 if (!rparen && (rop == PLUS || rop == MINUS)) 4715 return true; 4716 return false; 4717 } 4718 4719 if (op == LOGOR) { 4720 if (!lparen && lop == LOGAND) 4721 return true; 4722 if (!rparen && rop == LOGAND) 4723 return true; 4724 return false; 4725 } 4726 4727 lint_assert(op == BITAND || op == BITXOR || op == BITOR); 4728 if (!lparen && lop != op) { 4729 if (lop == PLUS || lop == MINUS) 4730 return true; 4731 if (lop == BITAND || lop == BITXOR) 4732 return true; 4733 } 4734 if (!rparen && rop != op) { 4735 if (rop == PLUS || rop == MINUS) 4736 return true; 4737 if (rop == BITAND || rop == BITXOR) 4738 return true; 4739 } 4740 return false; 4741 } 4742 4743 /* 4744 * Print a warning if the given node has operands which should be 4745 * parenthesized. 4746 * 4747 * XXX Does not work if an operand is a constant expression. Constant 4748 * expressions are already folded. 4749 */ 4750 static void 4751 check_precedence_confusion(tnode_t *tn) 4752 { 4753 tnode_t *ln, *rn; 4754 4755 if (!hflag) 4756 return; 4757 4758 debug_node(tn); 4759 4760 lint_assert(is_binary(tn)); 4761 for (ln = tn->tn_left; ln->tn_op == CVT; ln = ln->tn_left) 4762 continue; 4763 for (rn = tn->tn_right; rn->tn_op == CVT; rn = rn->tn_left) 4764 continue; 4765 4766 if (is_confusing_precedence(tn->tn_op, 4767 ln->tn_op, ln->tn_parenthesized, 4768 rn->tn_op, rn->tn_parenthesized)) { 4769 /* precedence confusion possible: parenthesize! */ 4770 warning(169); 4771 } 4772 } 4773 4774 typedef struct stmt_expr { 4775 struct memory_block *se_mem; 4776 sym_t *se_sym; 4777 struct stmt_expr *se_enclosing; 4778 } stmt_expr; 4779 4780 static stmt_expr *stmt_exprs; 4781 4782 void 4783 begin_statement_expr(void) 4784 { 4785 stmt_expr *se = xmalloc(sizeof(*se)); 4786 se->se_mem = expr_save_memory(); 4787 se->se_sym = NULL; 4788 se->se_enclosing = stmt_exprs; 4789 stmt_exprs = se; 4790 } 4791 4792 void 4793 do_statement_expr(tnode_t *tn) 4794 { 4795 block_level--; 4796 mem_block_level--; 4797 stmt_exprs->se_sym = tn != NULL 4798 ? mktempsym(block_dup_type(tn->tn_type)) 4799 : NULL; /* after a syntax error */ 4800 mem_block_level++; 4801 block_level++; 4802 /* ({ }) is a GCC extension */ 4803 gnuism(320); 4804 } 4805 4806 tnode_t * 4807 end_statement_expr(void) 4808 { 4809 stmt_expr *se = stmt_exprs; 4810 if (se->se_sym == NULL) 4811 return NULL; /* after a syntax error */ 4812 tnode_t *tn = build_name(se->se_sym, false); 4813 (void)expr_save_memory(); /* leak */ 4814 expr_restore_memory(se->se_mem); 4815 stmt_exprs = se->se_enclosing; 4816 free(se); 4817 return tn; 4818 } 4819
Indexes created Tue Sep 23 02:09:52 GMT 2025