tree.c revision 1.487
1 /* $NetBSD: tree.c,v 1.487 2023/01/08 15:22:33 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 1.487 2023/01/08 15:22:33 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 uint64_t 108 u64_fill_right(uint64_t x) 109 { 110 x |= x >> 1; 111 x |= x >> 2; 112 x |= x >> 4; 113 x |= x >> 8; 114 x |= x >> 16; 115 x |= x >> 32; 116 return x; 117 } 118 119 static unsigned 120 width_in_bits(const type_t *tp) 121 { 122 123 lint_assert(is_integer(tp->t_tspec)); 124 return tp->t_bitfield ? tp->t_flen : size_in_bits(tp->t_tspec); 125 } 126 127 static bool 128 ic_maybe_signed(const type_t *tp, const integer_constraints *ic) 129 { 130 131 return !is_uinteger(tp->t_tspec) && 132 (ic->bclr & ((uint64_t)1 << 63)) == 0; 133 } 134 135 static integer_constraints 136 ic_any(const type_t *tp) 137 { 138 integer_constraints c; 139 140 uint64_t vbits = value_bits(width_in_bits(tp)); 141 if (is_uinteger(tp->t_tspec)) { 142 c.smin = INT64_MIN; 143 c.smax = INT64_MAX; 144 c.umin = 0; 145 c.umax = vbits; 146 c.bset = 0; 147 c.bclr = ~c.umax; 148 } else { 149 c.smin = (int64_t)-1 - (int64_t)(vbits >> 1); 150 c.smax = (int64_t)(vbits >> 1); 151 c.umin = 0; 152 c.umax = UINT64_MAX; 153 c.bset = 0; 154 c.bclr = 0; 155 } 156 return c; 157 } 158 159 static integer_constraints 160 ic_con(const type_t *tp, const val_t *v) 161 { 162 integer_constraints c; 163 164 lint_assert(is_integer(tp->t_tspec)); 165 int64_t s = v->v_quad; 166 uint64_t u = (uint64_t)s; 167 c.smin = s; 168 c.smax = s; 169 c.umin = u; 170 c.umax = u; 171 c.bset = u; 172 c.bclr = ~u; 173 return c; 174 } 175 176 static integer_constraints 177 ic_cvt(const type_t *ntp, const type_t *otp, integer_constraints a) 178 { 179 180 if (width_in_bits(ntp) > width_in_bits(otp) && 181 is_uinteger(otp->t_tspec)) 182 return a; 183 return ic_any(ntp); 184 } 185 186 static integer_constraints 187 ic_bitand(integer_constraints a, integer_constraints b) 188 { 189 integer_constraints c; 190 191 c.smin = INT64_MIN; 192 c.smax = INT64_MAX; 193 c.umin = 0; 194 c.umax = UINT64_MAX; 195 c.bset = a.bset & b.bset; 196 c.bclr = a.bclr | b.bclr; 197 return c; 198 } 199 200 static integer_constraints 201 ic_bitor(integer_constraints a, integer_constraints b) 202 { 203 integer_constraints c; 204 205 c.smin = INT64_MIN; 206 c.smax = INT64_MAX; 207 c.umin = 0; 208 c.umax = UINT64_MAX; 209 c.bset = a.bset | b.bset; 210 c.bclr = a.bclr & b.bclr; 211 return c; 212 } 213 214 static integer_constraints 215 ic_mod(const type_t *tp, integer_constraints a, integer_constraints b) 216 { 217 integer_constraints c; 218 219 if (ic_maybe_signed(tp, &a) || ic_maybe_signed(tp, &b)) 220 return ic_any(tp); 221 222 c.smin = INT64_MIN; 223 c.smax = INT64_MAX; 224 c.umin = 0; 225 c.umax = b.umax - 1; 226 c.bset = 0; 227 c.bclr = ~u64_fill_right(c.umax); 228 return c; 229 } 230 231 static integer_constraints 232 ic_shl(const type_t *tp, integer_constraints a, integer_constraints b) 233 { 234 integer_constraints c; 235 unsigned int amount; 236 237 if (ic_maybe_signed(tp, &a)) 238 return ic_any(tp); 239 240 if (b.smin == b.smax && b.smin >= 0 && b.smin < 64) 241 amount = (unsigned int)b.smin; 242 else if (b.umin == b.umax && b.umin < 64) 243 amount = (unsigned int)b.umin; 244 else 245 return ic_any(tp); 246 247 c.smin = INT64_MIN; 248 c.smax = INT64_MAX; 249 c.umin = 0; 250 c.umax = UINT64_MAX; 251 c.bset = a.bset << amount; 252 c.bclr = a.bclr << amount | (((uint64_t)1 << amount) - 1); 253 return c; 254 } 255 256 static integer_constraints 257 ic_shr(const type_t *tp, integer_constraints a, integer_constraints b) 258 { 259 integer_constraints c; 260 unsigned int amount; 261 262 if (ic_maybe_signed(tp, &a)) 263 return ic_any(tp); 264 265 if (b.smin == b.smax && b.smin >= 0 && b.smin < 64) 266 amount = (unsigned int)b.smin; 267 else if (b.umin == b.umax && b.umin < 64) 268 amount = (unsigned int)b.umin; 269 else 270 return ic_any(tp); 271 272 c.smin = INT64_MIN; 273 c.smax = INT64_MAX; 274 c.umin = 0; 275 c.umax = UINT64_MAX; 276 c.bset = a.bset >> amount; 277 c.bclr = a.bclr >> amount | ~(~(uint64_t)0 >> amount); 278 return c; 279 } 280 281 static integer_constraints 282 ic_expr(const tnode_t *tn) 283 { 284 integer_constraints lc, rc; 285 286 lint_assert(is_integer(tn->tn_type->t_tspec)); 287 288 switch (tn->tn_op) { 289 case CON: 290 return ic_con(tn->tn_type, tn->tn_val); 291 case CVT: 292 if (!is_integer(tn->tn_left->tn_type->t_tspec)) 293 return ic_any(tn->tn_type); 294 lc = ic_expr(tn->tn_left); 295 return ic_cvt(tn->tn_type, tn->tn_left->tn_type, lc); 296 case MOD: 297 lc = ic_expr(before_conversion(tn->tn_left)); 298 rc = ic_expr(before_conversion(tn->tn_right)); 299 return ic_mod(tn->tn_type, lc, rc); 300 case SHL: 301 lc = ic_expr(tn->tn_left); 302 rc = ic_expr(tn->tn_right); 303 return ic_shl(tn->tn_type, lc, rc); 304 case SHR: 305 lc = ic_expr(tn->tn_left); 306 rc = ic_expr(tn->tn_right); 307 return ic_shr(tn->tn_type, lc, rc); 308 case BITAND: 309 lc = ic_expr(tn->tn_left); 310 rc = ic_expr(tn->tn_right); 311 return ic_bitand(lc, rc); 312 case BITOR: 313 lc = ic_expr(tn->tn_left); 314 rc = ic_expr(tn->tn_right); 315 return ic_bitor(lc, rc); 316 default: 317 return ic_any(tn->tn_type); 318 } 319 } 320 321 static const char * 322 op_name(op_t op) 323 { 324 return modtab[op].m_name; 325 } 326 327 /* Build 'pointer to tp', 'array of tp' or 'function returning tp'. */ 328 type_t * 329 block_derive_type(type_t *tp, tspec_t t) 330 { 331 type_t *tp2; 332 333 tp2 = block_zero_alloc(sizeof(*tp2)); 334 tp2->t_tspec = t; 335 tp2->t_subt = tp; 336 return tp2; 337 } 338 339 /* 340 * Derive 'pointer to tp' or 'function returning tp'. 341 * The memory is freed at the end of the current expression. 342 */ 343 type_t * 344 expr_derive_type(type_t *tp, tspec_t t) 345 { 346 type_t *tp2; 347 348 tp2 = expr_zero_alloc(sizeof(*tp2)); 349 tp2->t_tspec = t; 350 tp2->t_subt = tp; 351 return tp2; 352 } 353 354 /* 355 * Create a node for a constant. 356 */ 357 tnode_t * 358 build_constant(type_t *tp, val_t *v) 359 { 360 tnode_t *n; 361 362 n = expr_alloc_tnode(); 363 n->tn_op = CON; 364 n->tn_type = tp; 365 n->tn_val = expr_zero_alloc(sizeof(*n->tn_val)); 366 n->tn_val->v_tspec = tp->t_tspec; 367 n->tn_val->v_unsigned_since_c90 = v->v_unsigned_since_c90; 368 n->tn_val->v_u = v->v_u; 369 free(v); 370 return n; 371 } 372 373 static tnode_t * 374 build_integer_constant(tspec_t t, int64_t q) 375 { 376 tnode_t *n; 377 378 n = expr_alloc_tnode(); 379 n->tn_op = CON; 380 n->tn_type = gettyp(t); 381 n->tn_val = expr_zero_alloc(sizeof(*n->tn_val)); 382 n->tn_val->v_tspec = t; 383 n->tn_val->v_quad = q; 384 return n; 385 } 386 387 static void 388 fallback_symbol(sym_t *sym) 389 { 390 391 if (fallback_symbol_strict_bool(sym)) 392 return; 393 394 if (block_level > 0 && (strcmp(sym->s_name, "__FUNCTION__") == 0 || 395 strcmp(sym->s_name, "__PRETTY_FUNCTION__") == 0)) { 396 /* __FUNCTION__/__PRETTY_FUNCTION__ is a GCC extension */ 397 gnuism(316); 398 sym->s_type = block_derive_type(gettyp(CHAR), PTR); 399 sym->s_type->t_const = true; 400 return; 401 } 402 403 if (block_level > 0 && strcmp(sym->s_name, "__func__") == 0) { 404 if (!allow_c99) 405 /* __func__ is a C99 feature */ 406 warning(317); 407 sym->s_type = block_derive_type(gettyp(CHAR), PTR); 408 sym->s_type->t_const = true; 409 return; 410 } 411 412 /* '%s' undefined */ 413 error(99, sym->s_name); 414 } 415 416 /* 417 * Functions that are predeclared by GCC or other compilers can be called 418 * with arbitrary arguments. Since lint usually runs after a successful 419 * compilation, it's the compiler's job to catch any errors. 420 */ 421 bool 422 is_compiler_builtin(const char *name) 423 { 424 /* https://gcc.gnu.org/onlinedocs/gcc/C-Extensions.html */ 425 if (allow_gcc) { 426 if (strncmp(name, "__atomic_", 9) == 0 || 427 strncmp(name, "__builtin_", 10) == 0 || 428 strcmp(name, "alloca") == 0 || 429 /* obsolete but still in use, as of 2021 */ 430 strncmp(name, "__sync_", 7) == 0) 431 return true; 432 } 433 434 /* https://software.intel.com/sites/landingpage/IntrinsicsGuide/ */ 435 if (strncmp(name, "_mm_", 4) == 0) 436 return true; 437 438 return false; 439 } 440 441 static bool 442 str_endswith(const char *haystack, const char *needle) 443 { 444 size_t hlen = strlen(haystack); 445 size_t nlen = strlen(needle); 446 447 return nlen <= hlen && 448 memcmp(haystack + hlen - nlen, needle, nlen) == 0; 449 } 450 451 /* https://gcc.gnu.org/onlinedocs/gcc/Integer-Overflow-Builtins.html */ 452 static bool 453 is_gcc_bool_builtin(const char *name) 454 { 455 return strncmp(name, "__builtin_", 10) == 0 && 456 (str_endswith(name, "_overflow") || 457 str_endswith(name, "_overflow_p")); 458 } 459 460 static void 461 build_name_call(sym_t *sym) 462 { 463 464 if (is_compiler_builtin(sym->s_name)) { 465 /* 466 * Do not warn about these, just assume that 467 * they are regular functions compatible with 468 * non-prototype calling conventions. 469 */ 470 if (allow_gcc && is_gcc_bool_builtin(sym->s_name)) 471 sym->s_type = gettyp(BOOL); 472 473 } else if (allow_c99) { 474 /* function '%s' implicitly declared to return int */ 475 error(215, sym->s_name); 476 } else if (!allow_trad) { 477 /* function '%s' implicitly declared to return int */ 478 warning(215, sym->s_name); 479 } 480 481 /* XXX if !allow_c90, the symbol should be exported to level 0 */ 482 sym->s_type = block_derive_type(sym->s_type, FUNC); 483 } 484 485 /* Create a node for a name (symbol table entry). */ 486 tnode_t * 487 build_name(sym_t *sym, bool is_funcname) 488 { 489 tnode_t *n; 490 491 if (sym->s_scl == NOSCL && !in_gcc_attribute) { 492 sym->s_scl = EXTERN; 493 sym->s_def = DECL; 494 if (is_funcname) 495 build_name_call(sym); 496 else 497 fallback_symbol(sym); 498 } 499 500 lint_assert(sym->s_kind == FVFT || sym->s_kind == FMEMBER); 501 502 n = expr_alloc_tnode(); 503 n->tn_type = sym->s_type; 504 if (sym->s_scl == BOOL_CONST) { 505 n->tn_op = CON; 506 n->tn_val = expr_zero_alloc(sizeof(*n->tn_val)); 507 n->tn_val->v_tspec = BOOL; 508 n->tn_val->v_quad = sym->u.s_bool_constant ? 1 : 0; 509 } else if (sym->s_scl == ENUM_CONST) { 510 n->tn_op = CON; 511 n->tn_val = expr_zero_alloc(sizeof(*n->tn_val)); 512 n->tn_val->v_tspec = INT; /* ENUM is in n->tn_type */ 513 n->tn_val->v_quad = sym->u.s_enum_constant; 514 } else { 515 n->tn_op = NAME; 516 n->tn_sym = sym; 517 if (sym->s_kind == FVFT && sym->s_type->t_tspec != FUNC) 518 n->tn_lvalue = true; 519 } 520 521 return n; 522 } 523 524 tnode_t * 525 build_string(strg_t *strg) 526 { 527 size_t len; 528 tnode_t *n; 529 type_t *tp; 530 531 len = strg->st_len; 532 533 n = expr_alloc_tnode(); 534 535 tp = expr_zero_alloc(sizeof(*tp)); 536 tp->t_tspec = ARRAY; 537 tp->t_subt = gettyp(strg->st_char ? CHAR : WCHAR); 538 tp->t_dim = (int)(len + 1); 539 540 n->tn_op = STRING; 541 n->tn_type = tp; 542 n->tn_lvalue = true; 543 544 n->tn_string = expr_zero_alloc(sizeof(*n->tn_string)); 545 n->tn_string->st_char = strg->st_char; 546 n->tn_string->st_len = len; 547 548 size_t chsize = strg->st_char ? sizeof(char) : sizeof(wchar_t); 549 size_t size = (len + 1) * chsize; 550 n->tn_string->st_mem = expr_zero_alloc(size); 551 (void)memcpy(n->tn_string->st_mem, strg->st_mem, size); 552 free(strg->st_mem); 553 free(strg); 554 555 return n; 556 } 557 558 /* 559 * Returns a symbol which has the same name as the msym argument and is a 560 * member of the struct or union specified by the tn argument. 561 */ 562 static sym_t * 563 struct_or_union_member(tnode_t *tn, op_t op, sym_t *msym) 564 { 565 struct_or_union *str; 566 type_t *tp; 567 sym_t *sym, *csym; 568 bool eq; 569 tspec_t t; 570 571 /* 572 * Remove the member if it was unknown until now, which means 573 * that no defined struct or union has a member with the same name. 574 */ 575 if (msym->s_scl == NOSCL) { 576 /* type '%s' does not have member '%s' */ 577 error(101, type_name(tn->tn_type), msym->s_name); 578 rmsym(msym); 579 msym->s_kind = FMEMBER; 580 msym->s_scl = MOS; 581 582 struct_or_union *sou = expr_zero_alloc(sizeof(*sou)); 583 sou->sou_tag = expr_zero_alloc(sizeof(*sou->sou_tag)); 584 sou->sou_tag->s_name = unnamed; 585 586 msym->u.s_member.sm_sou_type = sou; 587 /* 588 * The member sm_offset_in_bits is not needed here since this 589 * symbol can only be used for error reporting. 590 */ 591 return msym; 592 } 593 594 /* Set str to the tag of which msym is expected to be a member. */ 595 str = NULL; 596 t = (tp = tn->tn_type)->t_tspec; 597 if (op == POINT) { 598 if (is_struct_or_union(t)) 599 str = tp->t_str; 600 } else if (op == ARROW && t == PTR) { 601 t = (tp = tp->t_subt)->t_tspec; 602 if (is_struct_or_union(t)) 603 str = tp->t_str; 604 } 605 606 /* 607 * If this struct/union has a member with the name of msym, return it. 608 */ 609 if (str != NULL) { 610 for (sym = msym; sym != NULL; sym = sym->s_symtab_next) { 611 if (!is_member(sym)) 612 continue; 613 if (sym->u.s_member.sm_sou_type != str) 614 continue; 615 if (strcmp(sym->s_name, msym->s_name) != 0) 616 continue; 617 return sym; 618 } 619 } 620 621 /* 622 * Set eq to false if there are struct/union members with the same 623 * name and different types and/or offsets. 624 */ 625 eq = true; 626 for (csym = msym; csym != NULL; csym = csym->s_symtab_next) { 627 if (csym->s_scl != MOS && csym->s_scl != MOU) 628 continue; 629 if (strcmp(msym->s_name, csym->s_name) != 0) 630 continue; 631 for (sym = csym->s_symtab_next; sym != NULL; 632 sym = sym->s_symtab_next) { 633 bool w; 634 635 if (sym->s_scl != MOS && sym->s_scl != MOU) 636 continue; 637 if (strcmp(csym->s_name, sym->s_name) != 0) 638 continue; 639 if (csym->u.s_member.sm_offset_in_bits != 640 sym->u.s_member.sm_offset_in_bits) { 641 eq = false; 642 break; 643 } 644 w = false; 645 eq = types_compatible(csym->s_type, sym->s_type, 646 false, false, &w) && !w; 647 if (!eq) 648 break; 649 if (csym->s_bitfield != sym->s_bitfield) { 650 eq = false; 651 break; 652 } 653 if (csym->s_bitfield) { 654 type_t *tp1, *tp2; 655 656 tp1 = csym->s_type; 657 tp2 = sym->s_type; 658 if (tp1->t_flen != tp2->t_flen) { 659 eq = false; 660 break; 661 } 662 if (tp1->t_foffs != tp2->t_foffs) { 663 eq = false; 664 break; 665 } 666 } 667 } 668 if (!eq) 669 break; 670 } 671 672 /* 673 * Now handle the case in which the left operand refers really 674 * to a struct/union, but the right operand is not member of it. 675 */ 676 if (str != NULL) { 677 if (eq && !allow_c90) { 678 /* illegal use of member '%s' */ 679 warning(102, msym->s_name); 680 } else { 681 /* illegal use of member '%s' */ 682 error(102, msym->s_name); 683 } 684 return msym; 685 } 686 687 /* 688 * Now the left operand of ARROW does not point to a struct/union 689 * or the left operand of POINT is no struct/union. 690 */ 691 if (eq) { 692 if (op == POINT) { 693 if (!allow_c90) { 694 /* left operand of '.' must be struct ... */ 695 warning(103, type_name(tn->tn_type)); 696 } else { 697 /* left operand of '.' must be struct ... */ 698 error(103, type_name(tn->tn_type)); 699 } 700 } else { 701 if (!allow_c90 && tn->tn_type->t_tspec == PTR) { 702 /* left operand of '->' must be pointer ... */ 703 warning(104, type_name(tn->tn_type)); 704 } else { 705 /* left operand of '->' must be pointer ... */ 706 error(104, type_name(tn->tn_type)); 707 } 708 } 709 } else { 710 if (!allow_c90) { 711 /* non-unique member requires struct/union %s */ 712 error(105, op == POINT ? "object" : "pointer"); 713 } else { 714 /* unacceptable operand of '%s' */ 715 error(111, op_name(op)); 716 } 717 } 718 719 return msym; 720 } 721 722 tnode_t * 723 build_generic_selection(const tnode_t *expr, 724 struct generic_association *sel) 725 { 726 tnode_t *default_result = NULL; 727 728 for (; sel != NULL; sel = sel->ga_prev) { 729 if (expr != NULL && 730 types_compatible(sel->ga_arg, expr->tn_type, 731 false, false, NULL)) 732 return sel->ga_result; 733 else if (sel->ga_arg == NULL) 734 default_result = sel->ga_result; 735 } 736 return default_result; 737 } 738 739 /* 740 * Create a tree node for a binary operator and its two operands. Also called 741 * for unary operators; in that case rn is NULL. 742 * 743 * Function calls, sizeof and casts are handled elsewhere. 744 */ 745 tnode_t * 746 build_binary(tnode_t *ln, op_t op, bool sys, tnode_t *rn) 747 { 748 const mod_t *mp; 749 tnode_t *ntn; 750 type_t *rettp; 751 752 mp = &modtab[op]; 753 754 /* If there was an error in one of the operands, return. */ 755 if (ln == NULL || (mp->m_binary && rn == NULL)) 756 return NULL; 757 758 /* 759 * Apply class conversions to the left operand, but only if its 760 * value is needed or it is compared with zero. 761 */ 762 if (mp->m_value_context || mp->m_compares_with_zero) 763 ln = cconv(ln); 764 /* 765 * The right operand is almost always in a test or value context, 766 * except if it is a struct or union member. 767 */ 768 if (mp->m_binary && op != ARROW && op != POINT) 769 rn = cconv(rn); 770 771 /* 772 * Print some warnings for comparisons of unsigned values with 773 * constants lower than or equal to null. This must be done 774 * before promote() because otherwise unsigned char and unsigned 775 * short would be promoted to int. Types are also tested to be 776 * CHAR, which would also become int. 777 */ 778 if (mp->m_comparison) 779 check_integer_comparison(op, ln, rn); 780 781 if (mp->m_value_context || mp->m_compares_with_zero) 782 ln = promote(op, false, ln); 783 if (mp->m_binary && op != ARROW && op != POINT && 784 op != ASSIGN && op != RETURN && op != INIT) { 785 rn = promote(op, false, rn); 786 } 787 788 /* 789 * If the result of the operation is different for signed or 790 * unsigned operands and one of the operands is signed only in 791 * ANSI C, print a warning. 792 */ 793 if (mp->m_warn_if_left_unsigned_in_c90 && 794 ln->tn_op == CON && ln->tn_val->v_unsigned_since_c90) { 795 /* ANSI C treats constant as unsigned, op '%s' */ 796 warning(218, mp->m_name); 797 ln->tn_val->v_unsigned_since_c90 = false; 798 } 799 if (mp->m_warn_if_right_unsigned_in_c90 && 800 rn->tn_op == CON && rn->tn_val->v_unsigned_since_c90) { 801 /* ANSI C treats constant as unsigned, op '%s' */ 802 warning(218, mp->m_name); 803 rn->tn_val->v_unsigned_since_c90 = false; 804 } 805 806 /* Make sure both operands are of the same type */ 807 if (mp->m_balance_operands || (!allow_c90 && (op == SHL || op == SHR))) 808 balance(op, &ln, &rn); 809 810 /* 811 * Check types for compatibility with the operation and mutual 812 * compatibility. Return if there are serious problems. 813 */ 814 if (!typeok(op, 0, ln, rn)) 815 return NULL; 816 817 /* And now create the node. */ 818 switch (op) { 819 case POINT: 820 case ARROW: 821 ntn = build_struct_access(op, sys, ln, rn); 822 break; 823 case INCAFT: 824 case DECAFT: 825 case INCBEF: 826 case DECBEF: 827 ntn = build_prepost_incdec(op, sys, ln); 828 break; 829 case ADDR: 830 ntn = build_address(sys, ln, false); 831 break; 832 case INDIR: 833 ntn = new_tnode(INDIR, sys, ln->tn_type->t_subt, ln, NULL); 834 break; 835 case PLUS: 836 case MINUS: 837 ntn = build_plus_minus(op, sys, ln, rn); 838 break; 839 case SHL: 840 case SHR: 841 ntn = build_bit_shift(op, sys, ln, rn); 842 break; 843 case COLON: 844 ntn = build_colon(sys, ln, rn); 845 break; 846 case ASSIGN: 847 case MULASS: 848 case DIVASS: 849 case MODASS: 850 case ADDASS: 851 case SUBASS: 852 case SHLASS: 853 case SHRASS: 854 case ANDASS: 855 case XORASS: 856 case ORASS: 857 case RETURN: 858 case INIT: 859 ntn = build_assignment(op, sys, ln, rn); 860 break; 861 case COMMA: 862 case QUEST: 863 ntn = new_tnode(op, sys, rn->tn_type, ln, rn); 864 break; 865 case REAL: 866 case IMAG: 867 ntn = build_real_imag(op, sys, ln); 868 break; 869 default: 870 rettp = mp->m_returns_bool 871 ? gettyp(Tflag ? BOOL : INT) : ln->tn_type; 872 lint_assert(mp->m_binary == (rn != NULL)); 873 ntn = new_tnode(op, sys, rettp, ln, rn); 874 break; 875 } 876 877 /* Return if an error occurred. */ 878 if (ntn == NULL) 879 return NULL; 880 881 /* Print a warning if precedence confusion is possible */ 882 if (mp->m_possible_precedence_confusion) 883 check_precedence_confusion(ntn); 884 885 /* 886 * Print a warning if one of the operands is in a context where 887 * it is compared with zero and if this operand is a constant. 888 */ 889 if (hflag && !constcond_flag && 890 mp->m_compares_with_zero && 891 (ln->tn_op == CON || 892 ((mp->m_binary && op != QUEST) && rn->tn_op == CON)) && 893 /* XXX: rn->tn_system_dependent should be checked as well */ 894 !ln->tn_system_dependent) { 895 /* constant in conditional context */ 896 warning(161); 897 } 898 899 /* Fold if the operator requires it */ 900 if (mp->m_fold_constant_operands) { 901 if (ln->tn_op == CON && (!mp->m_binary || rn->tn_op == CON)) { 902 if (mp->m_compares_with_zero) { 903 ntn = fold_bool(ntn); 904 } else if (is_floating(ntn->tn_type->t_tspec)) { 905 ntn = fold_float(ntn); 906 } else { 907 ntn = fold(ntn); 908 } 909 } else if (op == QUEST && ln->tn_op == CON) { 910 ntn = ln->tn_val->v_quad != 0 911 ? rn->tn_left : rn->tn_right; 912 } 913 } 914 915 return ntn; 916 } 917 918 tnode_t * 919 build_unary(op_t op, bool sys, tnode_t *tn) 920 { 921 return build_binary(tn, op, sys, NULL); 922 } 923 924 tnode_t * 925 build_member_access(tnode_t *ln, op_t op, bool sys, sbuf_t *member) 926 { 927 sym_t *msym; 928 929 if (ln == NULL) 930 return NULL; 931 932 if (op == ARROW) { 933 /* must do this before struct_or_union_member is called */ 934 ln = cconv(ln); 935 } 936 msym = struct_or_union_member(ln, op, getsym(member)); 937 return build_binary(ln, op, sys, build_name(msym, false)); 938 } 939 940 /* 941 * Perform class conversions. 942 * 943 * Arrays of type T are converted into pointers to type T. 944 * Functions are converted to pointers to functions. 945 * Lvalues are converted to rvalues. 946 * 947 * C99 6.3 "Conversions" 948 * C99 6.3.2 "Other operands" 949 * C99 6.3.2.1 "Lvalues, arrays, and function designators" 950 */ 951 tnode_t * 952 cconv(tnode_t *tn) 953 { 954 type_t *tp; 955 956 /* 957 * Array-lvalue (array of type T) is converted into rvalue 958 * (pointer to type T) 959 */ 960 if (tn->tn_type->t_tspec == ARRAY) { 961 if (!tn->tn_lvalue) { 962 /* XXX print correct operator */ 963 /* %soperand of '%s' must be lvalue */ 964 gnuism(114, "", op_name(ADDR)); 965 } 966 tn = new_tnode(ADDR, tn->tn_sys, 967 expr_derive_type(tn->tn_type->t_subt, PTR), tn, NULL); 968 } 969 970 /* 971 * Expression of type function (function with return value of type T) 972 * in rvalue-expression (pointer to function with return value 973 * of type T) 974 */ 975 if (tn->tn_type->t_tspec == FUNC) 976 tn = build_address(tn->tn_sys, tn, true); 977 978 /* lvalue to rvalue */ 979 if (tn->tn_lvalue) { 980 tp = expr_dup_type(tn->tn_type); 981 /* C99 6.3.2.1p2 sentence 2 says to remove the qualifiers. */ 982 tp->t_const = tp->t_volatile = false; 983 tn = new_tnode(LOAD, tn->tn_sys, tp, tn, NULL); 984 } 985 986 return tn; 987 } 988 989 const tnode_t * 990 before_conversion(const tnode_t *tn) 991 { 992 while (tn->tn_op == CVT && !tn->tn_cast) 993 tn = tn->tn_left; 994 return tn; 995 } 996 997 static bool 998 is_null_pointer(const tnode_t *tn) 999 { 1000 tspec_t t = tn->tn_type->t_tspec; 1001 1002 return ((t == PTR && tn->tn_type->t_subt->t_tspec == VOID) || 1003 is_integer(t)) 1004 && (tn->tn_op == CON && tn->tn_val->v_quad == 0); 1005 } 1006 1007 /* 1008 * Most errors required by ANSI C are reported in struct_or_union_member(). 1009 * Here we only check for totally wrong things. 1010 */ 1011 static bool 1012 typeok_point(const tnode_t *ln, const type_t *ltp, tspec_t lt) 1013 { 1014 if (is_struct_or_union(lt)) 1015 return true; 1016 1017 if (lt == FUNC || lt == VOID || ltp->t_bitfield) 1018 goto wrong; 1019 1020 /* 1021 * Some C dialects from before C90 tolerated any lvalue on the 1022 * left-hand side of the '.' operator, allowing things like 1023 * char st[100]; st.st_mtime, assuming that the member 'st_mtime' 1024 * only occurred in a single struct; see typeok_arrow. 1025 */ 1026 if (ln->tn_lvalue) 1027 return true; 1028 1029 wrong: 1030 /* With allow_c90 we already got an error */ 1031 if (!allow_c90) 1032 /* unacceptable operand of '%s' */ 1033 error(111, op_name(POINT)); 1034 1035 return false; 1036 } 1037 1038 static bool 1039 typeok_arrow(tspec_t lt) 1040 { 1041 /* 1042 * C1978 Appendix A 14.1 says: <quote>In fact, any lvalue is allowed 1043 * before '.', and that lvalue is then assumed to have the form of 1044 * the structure of which the name of the right is a member. [...] 1045 * Such constructions are non-portable.</quote> 1046 */ 1047 if (lt == PTR || (!allow_c90 && is_integer(lt))) 1048 return true; 1049 1050 /* With allow_c90 we already got an error */ 1051 if (!allow_c90) 1052 /* unacceptable operand of '%s' */ 1053 error(111, op_name(ARROW)); 1054 return false; 1055 } 1056 1057 static bool 1058 typeok_incdec(op_t op, const tnode_t *tn, const type_t *tp) 1059 { 1060 /* operand has scalar type (checked in typeok) */ 1061 if (!tn->tn_lvalue) { 1062 if (tn->tn_op == CVT && tn->tn_cast && 1063 tn->tn_left->tn_op == LOAD) { 1064 /* a cast does not yield an lvalue */ 1065 error(163); 1066 } 1067 /* %soperand of '%s' must be lvalue */ 1068 error(114, "", op_name(op)); 1069 return false; 1070 } else if (tp->t_const) { 1071 if (allow_c90) 1072 /* %soperand of '%s' must be modifiable lvalue */ 1073 warning(115, "", op_name(op)); 1074 } 1075 return true; 1076 } 1077 1078 static bool 1079 typeok_address(const mod_t *mp, 1080 const tnode_t *tn, const type_t *tp, tspec_t t) 1081 { 1082 if (t == ARRAY || t == FUNC) { 1083 /* ok, a warning comes later (in build_address()) */ 1084 } else if (!tn->tn_lvalue) { 1085 if (tn->tn_op == CVT && tn->tn_cast && 1086 tn->tn_left->tn_op == LOAD) { 1087 /* a cast does not yield an lvalue */ 1088 error(163); 1089 } 1090 /* %soperand of '%s' must be lvalue */ 1091 error(114, "", mp->m_name); 1092 return false; 1093 } else if (is_scalar(t)) { 1094 if (tp->t_bitfield) { 1095 /* cannot take address of bit-field */ 1096 error(112); 1097 return false; 1098 } 1099 } else if (t != STRUCT && t != UNION) { 1100 /* unacceptable operand of '%s' */ 1101 error(111, mp->m_name); 1102 return false; 1103 } 1104 if (tn->tn_op == NAME && tn->tn_sym->s_register) { 1105 /* cannot take address of register '%s' */ 1106 error(113, tn->tn_sym->s_name); 1107 return false; 1108 } 1109 return true; 1110 } 1111 1112 static bool 1113 typeok_indir(const type_t *tp, tspec_t t) 1114 { 1115 1116 if (t != PTR) { 1117 /* cannot dereference non-pointer type '%s' */ 1118 error(96, type_name(tp)); 1119 return false; 1120 } 1121 return true; 1122 } 1123 1124 static bool 1125 typeok_plus(op_t op, 1126 const type_t *ltp, tspec_t lt, 1127 const type_t *rtp, tspec_t rt) 1128 { 1129 /* operands have scalar types (checked in typeok) */ 1130 if ((lt == PTR && !is_integer(rt)) || (rt == PTR && !is_integer(lt))) { 1131 warn_incompatible_types(op, ltp, lt, rtp, rt); 1132 return false; 1133 } 1134 return true; 1135 } 1136 1137 static bool 1138 typeok_minus(op_t op, 1139 const type_t *ltp, tspec_t lt, 1140 const type_t *rtp, tspec_t rt) 1141 { 1142 /* operands have scalar types (checked in typeok) */ 1143 if ((lt == PTR && rt != PTR && !is_integer(rt)) || 1144 (lt != PTR && rt == PTR)) { 1145 warn_incompatible_types(op, ltp, lt, rtp, rt); 1146 return false; 1147 } 1148 if (lt == PTR && rt == PTR) { 1149 if (!types_compatible(ltp->t_subt, rtp->t_subt, 1150 true, false, NULL)) { 1151 /* illegal pointer subtraction */ 1152 error(116); 1153 } 1154 } 1155 return true; 1156 } 1157 1158 static void 1159 typeok_shr(const mod_t *mp, 1160 const tnode_t *ln, tspec_t lt, 1161 const tnode_t *rn, tspec_t rt) 1162 { 1163 tspec_t olt, ort; 1164 1165 olt = before_conversion(ln)->tn_type->t_tspec; 1166 ort = before_conversion(rn)->tn_type->t_tspec; 1167 1168 /* operands have integer types (checked in typeok) */ 1169 if (pflag && !is_uinteger(olt)) { 1170 /* 1171 * The left operand is signed. This means that 1172 * the operation is (possibly) nonportable. 1173 */ 1174 if (ln->tn_op != CON) { 1175 /* bitwise '%s' on signed value possibly nonportable */ 1176 warning(117, mp->m_name); 1177 } else if (ln->tn_val->v_quad < 0) { 1178 /* bitwise '%s' on signed value nonportable */ 1179 warning(120, mp->m_name); 1180 } 1181 } else if (allow_trad && allow_c90 && 1182 !is_uinteger(olt) && is_uinteger(ort)) { 1183 /* 1184 * The left operand would become unsigned in 1185 * traditional C. 1186 */ 1187 if (hflag && (ln->tn_op != CON || ln->tn_val->v_quad < 0)) { 1188 /* semantics of '%s' change in ANSI C; use ... */ 1189 warning(118, mp->m_name); 1190 } 1191 } else if (allow_trad && allow_c90 && 1192 !is_uinteger(olt) && !is_uinteger(ort) && 1193 portable_size_in_bits(lt) < portable_size_in_bits(rt)) { 1194 /* 1195 * In traditional C the left operand would be extended 1196 * (possibly sign-extended) and then shifted. 1197 */ 1198 if (hflag && (ln->tn_op != CON || ln->tn_val->v_quad < 0)) { 1199 /* semantics of '%s' change in ANSI C; use ... */ 1200 warning(118, mp->m_name); 1201 } 1202 } 1203 } 1204 1205 static void 1206 typeok_shl(const mod_t *mp, tspec_t lt, tspec_t rt) 1207 { 1208 /* 1209 * C90 does not perform balancing for shift operations, 1210 * but traditional C does. If the width of the right operand 1211 * is greater than the width of the left operand, then in 1212 * traditional C the left operand would be extended to the 1213 * width of the right operand. For SHL this may result in 1214 * different results. 1215 */ 1216 if (portable_size_in_bits(lt) < portable_size_in_bits(rt)) { 1217 /* 1218 * XXX If both operands are constant, make sure 1219 * that there is really a difference between 1220 * ANSI C and traditional C. 1221 */ 1222 if (hflag && !allow_c99) 1223 /* semantics of '%s' change in ANSI C; use ... */ 1224 warning(118, mp->m_name); 1225 } 1226 } 1227 1228 static void 1229 typeok_shift(const type_t *ltp, tspec_t lt, const tnode_t *rn, tspec_t rt) 1230 { 1231 if (rn->tn_op != CON) 1232 return; 1233 1234 if (!is_uinteger(rt) && rn->tn_val->v_quad < 0) { 1235 /* negative shift */ 1236 warning(121); 1237 } else if ((uint64_t)rn->tn_val->v_quad == 1238 (uint64_t)size_in_bits(lt)) { 1239 /* shift amount %u equals bit-size of '%s' */ 1240 warning(267, (unsigned)rn->tn_val->v_quad, type_name(ltp)); 1241 } else if ((uint64_t)rn->tn_val->v_quad > (uint64_t)size_in_bits(lt)) { 1242 /* shift amount %llu is greater than bit-size %llu of '%s' */ 1243 warning(122, (unsigned long long)rn->tn_val->v_quad, 1244 (unsigned long long)size_in_bits(lt), 1245 tspec_name(lt)); 1246 } 1247 } 1248 1249 static bool 1250 is_typeok_eq(const tnode_t *ln, tspec_t lt, const tnode_t *rn, tspec_t rt) 1251 { 1252 if (lt == PTR && is_null_pointer(rn)) 1253 return true; 1254 if (rt == PTR && is_null_pointer(ln)) 1255 return true; 1256 return false; 1257 } 1258 1259 static bool 1260 typeok_compare(op_t op, 1261 const tnode_t *ln, const type_t *ltp, tspec_t lt, 1262 const tnode_t *rn, const type_t *rtp, tspec_t rt) 1263 { 1264 const char *lx, *rx; 1265 1266 if (lt == PTR && rt == PTR) { 1267 check_pointer_comparison(op, ln, rn); 1268 return true; 1269 } 1270 1271 if (lt != PTR && rt != PTR) 1272 return true; 1273 1274 if (!is_integer(lt) && !is_integer(rt)) { 1275 warn_incompatible_types(op, ltp, lt, rtp, rt); 1276 return false; 1277 } 1278 1279 lx = lt == PTR ? "pointer" : "integer"; 1280 rx = rt == PTR ? "pointer" : "integer"; 1281 /* illegal combination of %s '%s' and %s '%s', op '%s' */ 1282 warning(123, lx, type_name(ltp), rx, type_name(rtp), op_name(op)); 1283 return true; 1284 } 1285 1286 static bool 1287 typeok_quest(tspec_t lt, const tnode_t *rn) 1288 { 1289 if (!is_scalar(lt)) { 1290 /* first operand must have scalar type, op ? : */ 1291 error(170); 1292 return false; 1293 } 1294 lint_assert(before_conversion(rn)->tn_op == COLON); 1295 return true; 1296 } 1297 1298 static void 1299 typeok_colon_pointer(const mod_t *mp, const type_t *ltp, const type_t *rtp) 1300 { 1301 type_t *lstp = ltp->t_subt; 1302 type_t *rstp = rtp->t_subt; 1303 tspec_t lst = lstp->t_tspec; 1304 tspec_t rst = rstp->t_tspec; 1305 1306 if ((lst == VOID && rst == FUNC) || (lst == FUNC && rst == VOID)) { 1307 /* (void *)0 is handled in typeok_colon */ 1308 /* TODO: C99 behaves like C90 here. */ 1309 if (!allow_trad && !allow_c99) 1310 /* ANSI C forbids conversion of %s to %s, op %s */ 1311 warning(305, "function pointer", "'void *'", 1312 mp->m_name); 1313 return; 1314 } 1315 1316 if (pointer_types_are_compatible(lstp, rstp, true)) 1317 return; 1318 if (!types_compatible(lstp, rstp, true, false, NULL)) 1319 warn_incompatible_pointers(mp, ltp, rtp); 1320 } 1321 1322 static bool 1323 typeok_colon(const mod_t *mp, 1324 const tnode_t *ln, const type_t *ltp, tspec_t lt, 1325 const tnode_t *rn, const type_t *rtp, tspec_t rt) 1326 { 1327 1328 if (is_arithmetic(lt) && is_arithmetic(rt)) 1329 return true; 1330 if (lt == BOOL && rt == BOOL) 1331 return true; 1332 1333 if (lt == STRUCT && rt == STRUCT && ltp->t_str == rtp->t_str) 1334 return true; 1335 if (lt == UNION && rt == UNION && ltp->t_str == rtp->t_str) 1336 return true; 1337 1338 if (lt == PTR && is_null_pointer(rn)) 1339 return true; 1340 if (rt == PTR && is_null_pointer(ln)) 1341 return true; 1342 1343 if ((lt == PTR && is_integer(rt)) || (is_integer(lt) && rt == PTR)) { 1344 const char *lx = lt == PTR ? "pointer" : "integer"; 1345 const char *rx = rt == PTR ? "pointer" : "integer"; 1346 /* illegal combination of %s '%s' and %s '%s', op '%s' */ 1347 warning(123, lx, type_name(ltp), 1348 rx, type_name(rtp), mp->m_name); 1349 return true; 1350 } 1351 1352 if (lt == VOID || rt == VOID) { 1353 if (lt != VOID || rt != VOID) 1354 /* incompatible types '%s' and '%s' in conditional */ 1355 warning(126, type_name(ltp), type_name(rtp)); 1356 return true; 1357 } 1358 1359 if (lt == PTR && rt == PTR) { 1360 typeok_colon_pointer(mp, ltp, rtp); 1361 return true; 1362 } 1363 1364 /* incompatible types '%s' and '%s' in conditional */ 1365 error(126, type_name(ltp), type_name(rtp)); 1366 return false; 1367 } 1368 1369 static bool 1370 typeok_assign(op_t op, const tnode_t *ln, const type_t *ltp, tspec_t lt) 1371 { 1372 if (op == RETURN || op == INIT || op == FARG) 1373 return true; 1374 1375 if (!ln->tn_lvalue) { 1376 if (ln->tn_op == CVT && ln->tn_cast && 1377 ln->tn_left->tn_op == LOAD) { 1378 /* a cast does not yield an lvalue */ 1379 error(163); 1380 } 1381 /* %soperand of '%s' must be lvalue */ 1382 error(114, "left ", op_name(op)); 1383 return false; 1384 } else if (ltp->t_const || (is_struct_or_union(lt) && 1385 has_constant_member(ltp))) { 1386 if (allow_c90) 1387 /* %soperand of '%s' must be modifiable lvalue */ 1388 warning(115, "left ", op_name(op)); 1389 } 1390 return true; 1391 } 1392 1393 /* Check the types using the information from modtab[]. */ 1394 static bool 1395 typeok_scalar(op_t op, const mod_t *mp, 1396 const type_t *ltp, tspec_t lt, 1397 const type_t *rtp, tspec_t rt) 1398 { 1399 if (mp->m_takes_bool && lt == BOOL && rt == BOOL) 1400 return true; 1401 if (mp->m_requires_integer) { 1402 if (!is_integer(lt) || (mp->m_binary && !is_integer(rt))) { 1403 warn_incompatible_types(op, ltp, lt, rtp, rt); 1404 return false; 1405 } 1406 } else if (mp->m_requires_integer_or_complex) { 1407 if ((!is_integer(lt) && !is_complex(lt)) || 1408 (mp->m_binary && (!is_integer(rt) && !is_complex(rt)))) { 1409 warn_incompatible_types(op, ltp, lt, rtp, rt); 1410 return false; 1411 } 1412 } else if (mp->m_requires_scalar) { 1413 if (!is_scalar(lt) || (mp->m_binary && !is_scalar(rt))) { 1414 warn_incompatible_types(op, ltp, lt, rtp, rt); 1415 return false; 1416 } 1417 } else if (mp->m_requires_arith) { 1418 if (!is_arithmetic(lt) || 1419 (mp->m_binary && !is_arithmetic(rt))) { 1420 warn_incompatible_types(op, ltp, lt, rtp, rt); 1421 return false; 1422 } 1423 } 1424 return true; 1425 } 1426 1427 /* 1428 * Check the types for specific operators and type combinations. 1429 * 1430 * At this point, the operands already conform to the type requirements of 1431 * the operator, such as being integer, floating or scalar. 1432 */ 1433 static bool 1434 typeok_op(op_t op, const mod_t *mp, int arg, 1435 const tnode_t *ln, const type_t *ltp, tspec_t lt, 1436 const tnode_t *rn, const type_t *rtp, tspec_t rt) 1437 { 1438 switch (op) { 1439 case ARROW: 1440 return typeok_arrow(lt); 1441 case POINT: 1442 return typeok_point(ln, ltp, lt); 1443 case INCBEF: 1444 case DECBEF: 1445 case INCAFT: 1446 case DECAFT: 1447 return typeok_incdec(op, ln, ltp); 1448 case INDIR: 1449 return typeok_indir(ltp, lt); 1450 case ADDR: 1451 return typeok_address(mp, ln, ltp, lt); 1452 case PLUS: 1453 return typeok_plus(op, ltp, lt, rtp, rt); 1454 case MINUS: 1455 return typeok_minus(op, ltp, lt, rtp, rt); 1456 case SHL: 1457 typeok_shl(mp, lt, rt); 1458 goto shift; 1459 case SHR: 1460 typeok_shr(mp, ln, lt, rn, rt); 1461 shift: 1462 typeok_shift(ltp, lt, rn, rt); 1463 break; 1464 case LT: 1465 case LE: 1466 case GT: 1467 case GE: 1468 compare: 1469 return typeok_compare(op, ln, ltp, lt, rn, rtp, rt); 1470 case EQ: 1471 case NE: 1472 if (is_typeok_eq(ln, lt, rn, rt)) 1473 break; 1474 goto compare; 1475 case QUEST: 1476 return typeok_quest(lt, rn); 1477 case COLON: 1478 return typeok_colon(mp, ln, ltp, lt, rn, rtp, rt); 1479 case ASSIGN: 1480 case INIT: 1481 case FARG: 1482 case RETURN: 1483 if (!check_assign_types_compatible(op, arg, ln, rn)) 1484 return false; 1485 goto assign; 1486 case MULASS: 1487 case DIVASS: 1488 case MODASS: 1489 goto assign; 1490 case ADDASS: 1491 case SUBASS: 1492 if ((lt == PTR && !is_integer(rt)) || rt == PTR) { 1493 warn_incompatible_types(op, ltp, lt, rtp, rt); 1494 return false; 1495 } 1496 goto assign; 1497 case SHLASS: 1498 goto assign; 1499 case SHRASS: 1500 if (pflag && !is_uinteger(lt) && 1501 !(!allow_c90 && is_uinteger(rt))) { 1502 /* bitwise '%s' on signed value possibly nonportable */ 1503 warning(117, mp->m_name); 1504 } 1505 goto assign; 1506 case ANDASS: 1507 case XORASS: 1508 case ORASS: 1509 assign: 1510 return typeok_assign(op, ln, ltp, lt); 1511 case COMMA: 1512 if (!modtab[ln->tn_op].m_has_side_effect) 1513 check_null_effect(ln); 1514 break; 1515 default: 1516 break; 1517 } 1518 return true; 1519 } 1520 1521 static void 1522 typeok_enum(op_t op, const mod_t *mp, int arg, 1523 const tnode_t *ln, const type_t *ltp, 1524 const tnode_t *rn, const type_t *rtp) 1525 { 1526 if (mp->m_bad_on_enum && 1527 (ltp->t_is_enum || (mp->m_binary && rtp->t_is_enum))) { 1528 check_bad_enum_operation(op, ln, rn); 1529 } else if (mp->m_valid_on_enum && 1530 (ltp->t_is_enum && rtp != NULL && rtp->t_is_enum)) { 1531 check_enum_type_mismatch(op, arg, ln, rn); 1532 } else if (mp->m_valid_on_enum && 1533 (ltp->t_is_enum || (rtp != NULL && rtp->t_is_enum))) { 1534 check_enum_int_mismatch(op, arg, ln, rn); 1535 } 1536 } 1537 1538 /* Perform most type checks. Return whether the types are ok. */ 1539 bool 1540 typeok(op_t op, int arg, const tnode_t *ln, const tnode_t *rn) 1541 { 1542 const mod_t *mp; 1543 tspec_t lt, rt; 1544 type_t *ltp, *rtp; 1545 1546 mp = &modtab[op]; 1547 1548 lint_assert((ltp = ln->tn_type) != NULL); 1549 lt = ltp->t_tspec; 1550 1551 if (mp->m_binary) { 1552 lint_assert((rtp = rn->tn_type) != NULL); 1553 rt = rtp->t_tspec; 1554 } else { 1555 rtp = NULL; 1556 rt = NOTSPEC; 1557 } 1558 1559 if (Tflag && !typeok_scalar_strict_bool(op, mp, arg, ln, rn)) 1560 return false; 1561 if (!typeok_scalar(op, mp, ltp, lt, rtp, rt)) 1562 return false; 1563 1564 if (!typeok_op(op, mp, arg, ln, ltp, lt, rn, rtp, rt)) 1565 return false; 1566 1567 typeok_enum(op, mp, arg, ln, ltp, rn, rtp); 1568 return true; 1569 } 1570 1571 static void 1572 check_pointer_comparison(op_t op, const tnode_t *ln, const tnode_t *rn) 1573 { 1574 type_t *ltp, *rtp; 1575 tspec_t lst, rst; 1576 const char *lsts, *rsts; 1577 1578 lst = (ltp = ln->tn_type)->t_subt->t_tspec; 1579 rst = (rtp = rn->tn_type)->t_subt->t_tspec; 1580 1581 if (lst == VOID || rst == VOID) { 1582 /* TODO: C99 behaves like C90 here. */ 1583 if ((!allow_trad && !allow_c99) && 1584 (lst == FUNC || rst == FUNC)) { 1585 /* (void *)0 already handled in typeok() */ 1586 *(lst == FUNC ? &lsts : &rsts) = "function pointer"; 1587 *(lst == VOID ? &lsts : &rsts) = "'void *'"; 1588 /* ANSI C forbids comparison of %s with %s */ 1589 warning(274, lsts, rsts); 1590 } 1591 return; 1592 } 1593 1594 if (!types_compatible(ltp->t_subt, rtp->t_subt, true, false, NULL)) { 1595 warn_incompatible_pointers(&modtab[op], ltp, rtp); 1596 return; 1597 } 1598 1599 if (lst == FUNC && rst == FUNC) { 1600 /* TODO: C99 behaves like C90 here, see C99 6.5.8p2. */ 1601 if ((!allow_trad && !allow_c99) && op != EQ && op != NE) 1602 /* ANSI C forbids ordered comparisons of ... */ 1603 warning(125); 1604 } 1605 } 1606 1607 static bool 1608 is_direct_function_call(const tnode_t *tn, const char **out_name) 1609 { 1610 1611 if (!(tn->tn_op == CALL && 1612 tn->tn_left->tn_op == ADDR && 1613 tn->tn_left->tn_left->tn_op == NAME)) 1614 return false; 1615 1616 *out_name = tn->tn_left->tn_left->tn_sym->s_name; 1617 return true; 1618 } 1619 1620 static bool 1621 is_unconst_function(const char *name) 1622 { 1623 1624 return strcmp(name, "memchr") == 0 || 1625 strcmp(name, "strchr") == 0 || 1626 strcmp(name, "strpbrk") == 0 || 1627 strcmp(name, "strrchr") == 0 || 1628 strcmp(name, "strstr") == 0; 1629 } 1630 1631 static bool 1632 is_const_char_pointer(const tnode_t *tn) 1633 { 1634 const type_t *tp; 1635 1636 /* 1637 * For traditional reasons, C99 6.4.5p5 defines that string literals 1638 * have type 'char[]'. They are often implicitly converted to 1639 * 'char *', for example when they are passed as function arguments. 1640 * 1641 * C99 6.4.5p6 further defines that modifying a string that is 1642 * constructed from a string literal invokes undefined behavior. 1643 * 1644 * Out of these reasons, string literals are treated as 'effectively 1645 * const' here. 1646 */ 1647 if (tn->tn_op == CVT && 1648 tn->tn_left->tn_op == ADDR && 1649 tn->tn_left->tn_left->tn_op == STRING) 1650 return true; 1651 1652 tp = before_conversion(tn)->tn_type; 1653 return tp->t_tspec == PTR && 1654 tp->t_subt->t_tspec == CHAR && 1655 tp->t_subt->t_const; 1656 } 1657 1658 static bool 1659 is_const_pointer(const tnode_t *tn) 1660 { 1661 const type_t *tp; 1662 1663 tp = before_conversion(tn)->tn_type; 1664 return tp->t_tspec == PTR && tp->t_subt->t_const; 1665 } 1666 1667 static bool 1668 is_first_arg_const_char_pointer(const tnode_t *tn) 1669 { 1670 const tnode_t *an; 1671 1672 an = tn->tn_right; 1673 if (an == NULL) 1674 return false; 1675 1676 while (an->tn_right != NULL) 1677 an = an->tn_right; 1678 return is_const_char_pointer(an->tn_left); 1679 } 1680 1681 static bool 1682 is_second_arg_const_pointer(const tnode_t *tn) 1683 { 1684 const tnode_t *an; 1685 1686 an = tn->tn_right; 1687 if (an == NULL || an->tn_right == NULL) 1688 return false; 1689 1690 while (an->tn_right->tn_right != NULL) 1691 an = an->tn_right; 1692 return is_const_pointer(an->tn_left); 1693 } 1694 1695 static void 1696 check_unconst_function(const type_t *lstp, const tnode_t *rn) 1697 { 1698 const char *function_name; 1699 1700 if (lstp->t_tspec == CHAR && !lstp->t_const && 1701 is_direct_function_call(rn, &function_name) && 1702 is_unconst_function(function_name) && 1703 is_first_arg_const_char_pointer(rn)) { 1704 /* call to '%s' effectively discards 'const' from argument */ 1705 warning(346, function_name); 1706 } 1707 1708 if (!lstp->t_const && 1709 is_direct_function_call(rn, &function_name) && 1710 strcmp(function_name, "bsearch") == 0 && 1711 is_second_arg_const_pointer(rn)) { 1712 /* call to '%s' effectively discards 'const' from argument */ 1713 warning(346, function_name); 1714 } 1715 } 1716 1717 static void 1718 check_assign_void_pointer(op_t op, int arg, 1719 tspec_t lt, tspec_t lst, 1720 tspec_t rt, tspec_t rst) 1721 { 1722 const char *lts, *rts; 1723 1724 if (!(lt == PTR && rt == PTR && (lst == VOID || rst == VOID))) 1725 return; 1726 /* two pointers, at least one pointer to void */ 1727 1728 /* TODO: C99 behaves like C90 here. */ 1729 if (!((!allow_trad && !allow_c99) && (lst == FUNC || rst == FUNC))) 1730 return; 1731 /* comb. of ptr to func and ptr to void */ 1732 1733 *(lst == FUNC ? <s : &rts) = "function pointer"; 1734 *(lst == VOID ? <s : &rts) = "'void *'"; 1735 1736 switch (op) { 1737 case INIT: 1738 case RETURN: 1739 /* ANSI C forbids conversion of %s to %s */ 1740 warning(303, rts, lts); 1741 break; 1742 case FARG: 1743 /* ANSI C forbids conversion of %s to %s, arg #%d */ 1744 warning(304, rts, lts, arg); 1745 break; 1746 default: 1747 /* ANSI C forbids conversion of %s to %s, op %s */ 1748 warning(305, rts, lts, op_name(op)); 1749 break; 1750 } 1751 } 1752 1753 static bool 1754 check_assign_void_pointer_compat(op_t op, int arg, 1755 const type_t *const ltp, tspec_t const lt, 1756 const type_t *const lstp, tspec_t const lst, 1757 const tnode_t *const rn, 1758 const type_t *const rtp, tspec_t const rt, 1759 const type_t *const rstp, tspec_t const rst) 1760 { 1761 if (!(lt == PTR && rt == PTR && (lst == VOID || rst == VOID || 1762 types_compatible(lstp, rstp, 1763 true, false, NULL)))) 1764 return false; 1765 1766 /* compatible pointer types (qualifiers ignored) */ 1767 if (allow_c90 && 1768 ((!lstp->t_const && rstp->t_const) || 1769 (!lstp->t_volatile && rstp->t_volatile))) { 1770 /* left side has not all qualifiers of right */ 1771 switch (op) { 1772 case INIT: 1773 case RETURN: 1774 /* incompatible pointer types to '%s' and '%s' */ 1775 warning(182, type_name(lstp), type_name(rstp)); 1776 break; 1777 case FARG: 1778 /* converting '%s' to incompatible '%s' ... */ 1779 warning(153, 1780 type_name(rtp), type_name(ltp), arg); 1781 break; 1782 default: 1783 /* operands of '%s' have incompatible pointer ... */ 1784 warning(128, op_name(op), 1785 type_name(lstp), type_name(rstp)); 1786 break; 1787 } 1788 } 1789 1790 if (allow_c90) 1791 check_unconst_function(lstp, rn); 1792 1793 return true; 1794 } 1795 1796 static bool 1797 check_assign_pointer_integer(op_t op, int arg, 1798 const type_t *const ltp, tspec_t const lt, 1799 const type_t *const rtp, tspec_t const rt) 1800 { 1801 const char *lx, *rx; 1802 1803 if (!((lt == PTR && is_integer(rt)) || (is_integer(lt) && rt == PTR))) 1804 return false; 1805 1806 lx = lt == PTR ? "pointer" : "integer"; 1807 rx = rt == PTR ? "pointer" : "integer"; 1808 1809 switch (op) { 1810 case INIT: 1811 case RETURN: 1812 /* illegal combination of %s '%s' and %s '%s' */ 1813 warning(183, lx, type_name(ltp), rx, type_name(rtp)); 1814 break; 1815 case FARG: 1816 /* illegal combination of %s '%s' and %s '%s', arg #%d */ 1817 warning(154, 1818 lx, type_name(ltp), rx, type_name(rtp), arg); 1819 break; 1820 default: 1821 /* illegal combination of %s '%s' and %s '%s', op '%s' */ 1822 warning(123, 1823 lx, type_name(ltp), rx, type_name(rtp), op_name(op)); 1824 break; 1825 } 1826 return true; 1827 } 1828 1829 static bool 1830 check_assign_pointer(op_t op, int arg, 1831 const type_t *ltp, tspec_t lt, 1832 const type_t *rtp, tspec_t rt) 1833 { 1834 if (!(lt == PTR && rt == PTR)) 1835 return false; 1836 1837 switch (op) { 1838 case RETURN: 1839 warn_incompatible_pointers(NULL, ltp, rtp); 1840 break; 1841 case FARG: 1842 /* converting '%s' to incompatible '%s' for ... */ 1843 warning(153, type_name(rtp), type_name(ltp), arg); 1844 break; 1845 default: 1846 warn_incompatible_pointers(&modtab[op], ltp, rtp); 1847 break; 1848 } 1849 return true; 1850 } 1851 1852 static void 1853 warn_assign(op_t op, int arg, 1854 const type_t *ltp, tspec_t lt, 1855 const type_t *rtp, tspec_t rt) 1856 { 1857 switch (op) { 1858 case INIT: 1859 /* cannot initialize '%s' from '%s' */ 1860 error(185, type_name(ltp), type_name(rtp)); 1861 break; 1862 case RETURN: 1863 /* function has return type '%s' but returns '%s' */ 1864 error(211, type_name(ltp), type_name(rtp)); 1865 break; 1866 case FARG: 1867 /* passing '%s' to incompatible '%s', arg #%d */ 1868 warning(155, type_name(rtp), type_name(ltp), arg); 1869 break; 1870 default: 1871 warn_incompatible_types(op, ltp, lt, rtp, rt); 1872 break; 1873 } 1874 } 1875 1876 /* 1877 * Checks type compatibility for ASSIGN, INIT, FARG and RETURN 1878 * and prints warnings/errors if necessary. 1879 * Returns whether the types are (almost) compatible. 1880 */ 1881 static bool 1882 check_assign_types_compatible(op_t op, int arg, 1883 const tnode_t *ln, const tnode_t *rn) 1884 { 1885 tspec_t lt, rt, lst = NOTSPEC, rst = NOTSPEC; 1886 type_t *ltp, *rtp, *lstp = NULL, *rstp = NULL; 1887 1888 if ((lt = (ltp = ln->tn_type)->t_tspec) == PTR) 1889 lst = (lstp = ltp->t_subt)->t_tspec; 1890 if ((rt = (rtp = rn->tn_type)->t_tspec) == PTR) 1891 rst = (rstp = rtp->t_subt)->t_tspec; 1892 1893 if (lt == BOOL && is_scalar(rt)) /* C99 6.3.1.2 */ 1894 return true; 1895 1896 if (is_arithmetic(lt) && (is_arithmetic(rt) || rt == BOOL)) 1897 return true; 1898 1899 if (is_struct_or_union(lt) && is_struct_or_union(rt)) 1900 /* both are struct or union */ 1901 return ltp->t_str == rtp->t_str; 1902 1903 /* a null pointer may be assigned to any pointer */ 1904 if (lt == PTR && is_null_pointer(rn)) 1905 return true; 1906 1907 check_assign_void_pointer(op, arg, lt, lst, rt, rst); 1908 1909 if (check_assign_void_pointer_compat(op, arg, 1910 ltp, lt, lstp, lst, rn, rtp, rt, rstp, rst)) 1911 return true; 1912 1913 if (check_assign_pointer_integer(op, arg, ltp, lt, rtp, rt)) 1914 return true; 1915 1916 if (check_assign_pointer(op, arg, ltp, lt, rtp, rt)) 1917 return true; 1918 1919 warn_assign(op, arg, ltp, lt, rtp, rt); 1920 return false; 1921 } 1922 1923 /* Prints a warning if a strange operator is used on an enum type. */ 1924 static void 1925 check_bad_enum_operation(op_t op, const tnode_t *ln, const tnode_t *rn) 1926 { 1927 1928 if (!eflag) 1929 return; 1930 1931 /* 1932 * Enum as offset to a pointer is an exception (otherwise enums 1933 * could not be used as array indices). 1934 */ 1935 if (op == PLUS && 1936 ((ln->tn_type->t_is_enum && rn->tn_type->t_tspec == PTR) || 1937 (rn->tn_type->t_is_enum && ln->tn_type->t_tspec == PTR))) { 1938 return; 1939 } 1940 1941 /* dubious operation on enum, op '%s' */ 1942 warning(241, op_name(op)); 1943 } 1944 1945 /* 1946 * Prints a warning if an operator is applied to two different enum types. 1947 */ 1948 static void 1949 check_enum_type_mismatch(op_t op, int arg, const tnode_t *ln, const tnode_t *rn) 1950 { 1951 const mod_t *mp; 1952 1953 mp = &modtab[op]; 1954 1955 if (ln->tn_type->t_enum != rn->tn_type->t_enum) { 1956 switch (op) { 1957 case INIT: 1958 /* enum type mismatch between '%s' and '%s' in ... */ 1959 warning(210, 1960 type_name(ln->tn_type), type_name(rn->tn_type)); 1961 break; 1962 case FARG: 1963 /* function expects '%s', passing '%s' for arg #%d */ 1964 warning(156, 1965 type_name(ln->tn_type), type_name(rn->tn_type), 1966 arg); 1967 break; 1968 case RETURN: 1969 /* function has return type '%s' but returns '%s' */ 1970 warning(211, 1971 type_name(ln->tn_type), type_name(rn->tn_type)); 1972 break; 1973 default: 1974 /* enum type mismatch: '%s' '%s' '%s' */ 1975 warning(130, type_name(ln->tn_type), mp->m_name, 1976 type_name(rn->tn_type)); 1977 break; 1978 } 1979 } else if (Pflag && mp->m_comparison && op != EQ && op != NE) { 1980 if (eflag) 1981 /* dubious comparison of enums, op '%s' */ 1982 warning(243, mp->m_name); 1983 } 1984 } 1985 1986 /* Prints a warning if the operands mix between enum and integer. */ 1987 static void 1988 check_enum_int_mismatch(op_t op, int arg, const tnode_t *ln, const tnode_t *rn) 1989 { 1990 1991 if (!eflag) 1992 return; 1993 1994 switch (op) { 1995 case INIT: 1996 /* 1997 * Initialization with 0 is allowed. Otherwise, all implicit 1998 * initializations would need to be warned upon as well. 1999 */ 2000 if (!rn->tn_type->t_is_enum && rn->tn_op == CON && 2001 is_integer(rn->tn_type->t_tspec) && 2002 rn->tn_val->v_quad == 0) { 2003 return; 2004 } 2005 /* initialization of '%s' with '%s' */ 2006 warning(277, type_name(ln->tn_type), type_name(rn->tn_type)); 2007 break; 2008 case FARG: 2009 /* combination of '%s' and '%s', arg #%d */ 2010 warning(278, 2011 type_name(ln->tn_type), type_name(rn->tn_type), arg); 2012 break; 2013 case RETURN: 2014 /* combination of '%s' and '%s' in return */ 2015 warning(279, type_name(ln->tn_type), type_name(rn->tn_type)); 2016 break; 2017 default: 2018 /* combination of '%s' and '%s', op '%s' */ 2019 warning(242, type_name(ln->tn_type), type_name(rn->tn_type), 2020 op_name(op)); 2021 break; 2022 } 2023 } 2024 2025 static void 2026 check_enum_array_index(const tnode_t *ln, const tnode_t *rn) 2027 { 2028 int max_array_index; 2029 int64_t max_enum_value; 2030 const struct sym *ec, *max_ec; 2031 const type_t *lt, *rt; 2032 2033 if (ln->tn_op != ADDR || ln->tn_left->tn_op != NAME) 2034 return; 2035 2036 lt = ln->tn_left->tn_type; 2037 if (lt->t_tspec != ARRAY || lt->t_incomplete_array) 2038 return; 2039 2040 if (rn->tn_op != CVT || !rn->tn_type->t_is_enum) 2041 return; 2042 if (rn->tn_left->tn_op != LOAD) 2043 return; 2044 2045 rt = rn->tn_left->tn_type; 2046 ec = rt->t_enum->en_first_enumerator; 2047 max_ec = ec; 2048 lint_assert(ec != NULL); 2049 for (ec = ec->s_next; ec != NULL; ec = ec->s_next) 2050 if (ec->u.s_enum_constant > max_ec->u.s_enum_constant) 2051 max_ec = ec; 2052 2053 max_enum_value = max_ec->u.s_enum_constant; 2054 lint_assert(INT_MIN <= max_enum_value && max_enum_value <= INT_MAX); 2055 2056 max_array_index = lt->t_dim - 1; 2057 if (max_enum_value == max_array_index) 2058 return; 2059 2060 /* 2061 * If the name of the largest enum constant contains 'MAX' or 'NUM', 2062 * that constant is typically not part of the allowed enum values but 2063 * a marker for the number of actual enum values. 2064 */ 2065 if (max_enum_value == max_array_index + 1 && 2066 (strstr(max_ec->s_name, "MAX") != NULL || 2067 strstr(max_ec->s_name, "max") != NULL || 2068 strstr(max_ec->s_name, "NUM") != NULL || 2069 strstr(max_ec->s_name, "num") != NULL)) 2070 return; 2071 2072 /* maximum value %d of '%s' does not match maximum array index %d */ 2073 warning(348, (int)max_enum_value, type_name(rt), max_array_index); 2074 print_previous_declaration(max_ec); 2075 } 2076 2077 /* 2078 * Build and initialize a new node. 2079 */ 2080 static tnode_t * 2081 new_tnode(op_t op, bool sys, type_t *type, tnode_t *ln, tnode_t *rn) 2082 { 2083 tnode_t *ntn; 2084 tspec_t t; 2085 #if 0 /* not yet */ 2086 size_t l; 2087 uint64_t rnum; 2088 #endif 2089 2090 ntn = expr_alloc_tnode(); 2091 2092 ntn->tn_op = op; 2093 ntn->tn_type = type; 2094 ntn->tn_sys = sys; 2095 ntn->tn_left = ln; 2096 ntn->tn_right = rn; 2097 2098 switch (op) { 2099 #if 0 /* not yet */ 2100 case SHR: 2101 if (rn->tn_op != CON) 2102 break; 2103 rnum = rn->tn_val->v_quad; 2104 l = type_size_in_bits(ln->tn_type) / CHAR_SIZE; 2105 t = ln->tn_type->t_tspec; 2106 switch (l) { 2107 case 8: 2108 if (rnum >= 56) 2109 t = UCHAR; 2110 else if (rnum >= 48) 2111 t = USHORT; 2112 else if (rnum >= 32) 2113 t = UINT; 2114 break; 2115 case 4: 2116 if (rnum >= 24) 2117 t = UCHAR; 2118 else if (rnum >= 16) 2119 t = USHORT; 2120 break; 2121 case 2: 2122 if (rnum >= 8) 2123 t = UCHAR; 2124 break; 2125 default: 2126 break; 2127 } 2128 if (t != ln->tn_type->t_tspec) 2129 ntn->tn_type->t_tspec = t; 2130 break; 2131 #endif 2132 case INDIR: 2133 case FSEL: 2134 lint_assert(ln->tn_type->t_tspec == PTR); 2135 t = ln->tn_type->t_subt->t_tspec; 2136 if (t != FUNC && t != VOID) 2137 ntn->tn_lvalue = true; 2138 break; 2139 default: 2140 break; 2141 } 2142 2143 return ntn; 2144 } 2145 2146 /* 2147 * Performs the "integer promotions" (C99 6.3.1.1p2), which convert small 2148 * integer types to either int or unsigned int. 2149 * 2150 * If allow_c90 is unset or the operand is a function argument with no type 2151 * information (no prototype or variable # of args), converts float to double. 2152 */ 2153 tnode_t * 2154 promote(op_t op, bool farg, tnode_t *tn) 2155 { 2156 tspec_t t; 2157 type_t *ntp; 2158 unsigned int len; 2159 2160 t = tn->tn_type->t_tspec; 2161 2162 if (!is_arithmetic(t)) 2163 return tn; 2164 2165 if (allow_c90) { 2166 /* 2167 * C99 6.3.1.1p2 requires for types with lower rank than int 2168 * that "If an int can represent all the values of the 2169 * original type, the value is converted to an int; otherwise 2170 * it is converted to an unsigned int", and that "All other 2171 * types are unchanged by the integer promotions". 2172 */ 2173 if (tn->tn_type->t_bitfield) { 2174 len = tn->tn_type->t_flen; 2175 if (len < size_in_bits(INT)) { 2176 t = INT; 2177 } else if (len == size_in_bits(INT)) { 2178 t = is_uinteger(t) ? UINT : INT; 2179 } 2180 } else if (t == CHAR || t == UCHAR || t == SCHAR) { 2181 t = (size_in_bits(CHAR) < size_in_bits(INT) 2182 || t != UCHAR) ? INT : UINT; 2183 } else if (t == SHORT || t == USHORT) { 2184 t = (size_in_bits(SHORT) < size_in_bits(INT) 2185 || t == SHORT) ? INT : UINT; 2186 } else if (t == ENUM) { 2187 t = INT; 2188 } else if (farg && t == FLOAT) { 2189 t = DOUBLE; 2190 } 2191 } else { 2192 /* 2193 * In traditional C, keep unsigned and promote FLOAT 2194 * to DOUBLE. 2195 */ 2196 if (t == UCHAR || t == USHORT) { 2197 t = UINT; 2198 } else if (t == CHAR || t == SCHAR || t == SHORT) { 2199 t = INT; 2200 } else if (t == FLOAT) { 2201 t = DOUBLE; 2202 } else if (t == ENUM) { 2203 t = INT; 2204 } 2205 } 2206 2207 if (t != tn->tn_type->t_tspec) { 2208 ntp = expr_dup_type(tn->tn_type); 2209 ntp->t_tspec = t; 2210 /* 2211 * Keep t_is_enum even though t_tspec gets converted from 2212 * ENUM to INT, so we are later able to check compatibility 2213 * of enum types. 2214 */ 2215 tn = convert(op, 0, ntp, tn); 2216 } 2217 2218 return tn; 2219 } 2220 2221 /* 2222 * Apply the "usual arithmetic conversions" (C99 6.3.1.8). 2223 * 2224 * This gives both operands the same type. 2225 * This is done in different ways for traditional C and C90. 2226 */ 2227 static void 2228 balance(op_t op, tnode_t **lnp, tnode_t **rnp) 2229 { 2230 tspec_t lt, rt, t; 2231 int i; 2232 bool u; 2233 type_t *ntp; 2234 static const tspec_t tl[] = { 2235 LDOUBLE, DOUBLE, FLOAT, 2236 #ifdef INT128_SIZE 2237 UINT128, INT128, 2238 #endif 2239 UQUAD, QUAD, 2240 ULONG, LONG, 2241 UINT, INT, 2242 }; 2243 2244 lt = (*lnp)->tn_type->t_tspec; 2245 rt = (*rnp)->tn_type->t_tspec; 2246 2247 if (!is_arithmetic(lt) || !is_arithmetic(rt)) 2248 return; 2249 2250 if (allow_c90) { 2251 if (lt == rt) { 2252 t = lt; 2253 } else if (lt == LCOMPLEX || rt == LCOMPLEX) { 2254 t = LCOMPLEX; 2255 } else if (lt == DCOMPLEX || rt == DCOMPLEX) { 2256 t = DCOMPLEX; 2257 } else if (lt == FCOMPLEX || rt == FCOMPLEX) { 2258 t = FCOMPLEX; 2259 } else if (lt == LDOUBLE || rt == LDOUBLE) { 2260 t = LDOUBLE; 2261 } else if (lt == DOUBLE || rt == DOUBLE) { 2262 t = DOUBLE; 2263 } else if (lt == FLOAT || rt == FLOAT) { 2264 t = FLOAT; 2265 } else { 2266 /* 2267 * If type A has more bits than type B it should 2268 * be able to hold all possible values of type B. 2269 */ 2270 if (size_in_bits(lt) > size_in_bits(rt)) { 2271 t = lt; 2272 } else if (size_in_bits(lt) < size_in_bits(rt)) { 2273 t = rt; 2274 } else { 2275 for (i = 3; tl[i] != INT; i++) { 2276 if (tl[i] == lt || tl[i] == rt) 2277 break; 2278 } 2279 if ((is_uinteger(lt) || is_uinteger(rt)) && 2280 !is_uinteger(tl[i])) { 2281 i--; 2282 } 2283 t = tl[i]; 2284 } 2285 } 2286 } else { 2287 /* Keep unsigned in traditional C */ 2288 u = is_uinteger(lt) || is_uinteger(rt); 2289 for (i = 0; tl[i] != INT; i++) { 2290 if (lt == tl[i] || rt == tl[i]) 2291 break; 2292 } 2293 t = tl[i]; 2294 if (u && is_integer(t) && !is_uinteger(t)) 2295 t = unsigned_type(t); 2296 } 2297 2298 if (t != lt) { 2299 ntp = expr_dup_type((*lnp)->tn_type); 2300 ntp->t_tspec = t; 2301 /* usual arithmetic conversion for '%s' from '%s' to '%s' */ 2302 query_message(4, op_name(op), 2303 type_name((*lnp)->tn_type), type_name(ntp)); 2304 *lnp = convert(op, 0, ntp, *lnp); 2305 } 2306 if (t != rt) { 2307 ntp = expr_dup_type((*rnp)->tn_type); 2308 ntp->t_tspec = t; 2309 /* usual arithmetic conversion for '%s' from '%s' to '%s' */ 2310 query_message(4, op_name(op), 2311 type_name((*rnp)->tn_type), type_name(ntp)); 2312 *rnp = convert(op, 0, ntp, *rnp); 2313 } 2314 } 2315 2316 static void 2317 convert_integer_from_floating(op_t op, const type_t *tp, const tnode_t *tn) 2318 { 2319 2320 if (op == CVT) 2321 /* cast from floating point '%s' to integer '%s' */ 2322 query_message(2, type_name(tn->tn_type), type_name(tp)); 2323 else 2324 /* implicit conversion from floating point '%s' to ... */ 2325 query_message(1, type_name(tn->tn_type), type_name(tp)); 2326 } 2327 2328 /* 2329 * Insert a conversion operator, which converts the type of the node 2330 * to another given type. 2331 * 2332 * Possible values for 'op': 2333 * CVT a cast-expression 2334 * binary integer promotion for one of the operands, or a usual 2335 * arithmetic conversion 2336 * binary plain or compound assignments to bit-fields 2337 * FARG 'arg' is the number of the argument (used for warnings) 2338 * NOOP several other implicit conversions 2339 * ... 2340 */ 2341 tnode_t * 2342 convert(op_t op, int arg, type_t *tp, tnode_t *tn) 2343 { 2344 tnode_t *ntn; 2345 tspec_t nt, ot; 2346 2347 nt = tp->t_tspec; 2348 ot = tn->tn_type->t_tspec; 2349 2350 if (allow_trad && allow_c90 && op == FARG) 2351 check_prototype_conversion(arg, nt, ot, tp, tn); 2352 2353 if (nt == BOOL) { 2354 /* No further checks. */ 2355 2356 } else if (is_integer(nt)) { 2357 if (ot == BOOL) { 2358 /* No further checks. */ 2359 } else if (is_integer(ot)) { 2360 convert_integer_from_integer(op, arg, nt, ot, tp, tn); 2361 } else if (is_floating(ot)) { 2362 convert_integer_from_floating(op, tp, tn); 2363 } else if (ot == PTR) { 2364 convert_integer_from_pointer(op, nt, tp, tn); 2365 } 2366 2367 } else if (is_floating(nt)) { 2368 /* No further checks. */ 2369 2370 } else if (nt == PTR) { 2371 if (is_null_pointer(tn)) { 2372 /* a null pointer may be assigned to any pointer. */ 2373 } else if (ot == PTR && op == CVT) { 2374 convert_pointer_from_pointer(tp, tn); 2375 } 2376 } 2377 2378 ntn = expr_alloc_tnode(); 2379 ntn->tn_op = CVT; 2380 ntn->tn_type = tp; 2381 ntn->tn_cast = op == CVT; 2382 ntn->tn_sys |= tn->tn_sys; 2383 ntn->tn_right = NULL; 2384 if (tn->tn_op != CON || nt == VOID) { 2385 ntn->tn_left = tn; 2386 } else { 2387 ntn->tn_op = CON; 2388 ntn->tn_val = expr_zero_alloc(sizeof(*ntn->tn_val)); 2389 convert_constant(op, arg, ntn->tn_type, ntn->tn_val, 2390 tn->tn_val); 2391 } 2392 2393 return ntn; 2394 } 2395 2396 static bool 2397 should_warn_about_prototype_conversion(tspec_t nt, 2398 tspec_t ot, const tnode_t *ptn) 2399 { 2400 2401 if (nt == ot) 2402 return false; 2403 2404 if (nt == ENUM && ot == INT) 2405 return false; 2406 2407 if (is_floating(nt) != is_floating(ot) || 2408 portable_size_in_bits(nt) != portable_size_in_bits(ot)) { 2409 /* representation and/or width change */ 2410 if (!is_integer(ot)) 2411 return true; 2412 /* 2413 * XXX: Investigate whether this rule makes sense; see 2414 * tests/usr.bin/xlint/lint1/platform_long.c. 2415 */ 2416 return portable_size_in_bits(ot) > portable_size_in_bits(INT); 2417 } 2418 2419 if (!hflag) 2420 return false; 2421 2422 /* 2423 * If the types differ only in sign and the argument has the same 2424 * representation in both types, print no warning. 2425 */ 2426 if (ptn->tn_op == CON && is_integer(nt) && 2427 signed_type(nt) == signed_type(ot) && 2428 !msb(ptn->tn_val->v_quad, ot)) 2429 return false; 2430 2431 return true; 2432 } 2433 2434 /* 2435 * Warn if a prototype causes a type conversion that is different from what 2436 * would happen to the same argument in the absence of a prototype. This 2437 * check is intended for code that needs to stay compatible with pre-C90 C. 2438 * 2439 * Errors/warnings about illegal type combinations are already printed 2440 * in check_assign_types_compatible(). 2441 */ 2442 static void 2443 check_prototype_conversion(int arg, tspec_t nt, tspec_t ot, type_t *tp, 2444 tnode_t *tn) 2445 { 2446 tnode_t *ptn; 2447 2448 if (!is_arithmetic(nt) || !is_arithmetic(ot)) 2449 return; 2450 2451 /* 2452 * If the type of the formal parameter is char/short, a warning 2453 * would be useless, because functions declared the old style 2454 * can't expect char/short arguments. 2455 */ 2456 if (nt == CHAR || nt == SCHAR || nt == UCHAR || 2457 nt == SHORT || nt == USHORT) 2458 return; 2459 2460 /* apply the default promotion */ 2461 ptn = promote(NOOP, true, tn); 2462 ot = ptn->tn_type->t_tspec; 2463 2464 if (should_warn_about_prototype_conversion(nt, ot, ptn)) { 2465 /* argument #%d is converted from '%s' to '%s' ... */ 2466 warning(259, arg, type_name(tn->tn_type), type_name(tp)); 2467 } 2468 } 2469 2470 /* 2471 * When converting a large integer type to a small integer type, in some 2472 * cases the value of the actual expression is further restricted than the 2473 * type bounds, such as in (expr & 0xFF) or (expr % 100) or (expr >> 24). 2474 * 2475 * See new_tnode, the '#if 0' code for SHR. 2476 */ 2477 static bool 2478 can_represent(const type_t *tp, const tnode_t *tn) 2479 { 2480 2481 debug_step("%s: type '%s'", __func__, type_name(tp)); 2482 debug_node(tn); 2483 2484 uint64_t nmask = value_bits(width_in_bits(tp)); 2485 if (!is_uinteger(tp->t_tspec)) 2486 nmask >>= 1; 2487 2488 integer_constraints c = ic_expr(tn); 2489 if ((~c.bclr & ~nmask) == 0) 2490 return true; 2491 2492 return false; 2493 } 2494 2495 static void 2496 convert_integer_from_integer(op_t op, int arg, tspec_t nt, tspec_t ot, 2497 type_t *tp, tnode_t *tn) 2498 { 2499 2500 if (tn->tn_op == CON) 2501 return; 2502 2503 if (op == CVT) 2504 return; 2505 2506 if (Pflag && pflag && aflag > 0 && 2507 portable_size_in_bits(nt) > portable_size_in_bits(ot) && 2508 is_uinteger(nt) != is_uinteger(ot)) { 2509 if (op == FARG) { 2510 /* conversion to '%s' may sign-extend ... */ 2511 warning(297, type_name(tp), arg); 2512 } else { 2513 /* conversion to '%s' may sign-extend ... */ 2514 warning(131, type_name(tp)); 2515 } 2516 } 2517 2518 if (Pflag && portable_size_in_bits(nt) > portable_size_in_bits(ot) && 2519 (tn->tn_op == PLUS || tn->tn_op == MINUS || tn->tn_op == MULT || 2520 tn->tn_op == SHL)) { 2521 /* suggest cast from '%s' to '%s' on op '%s' to ... */ 2522 warning(324, type_name(gettyp(ot)), type_name(tp), 2523 op_name(tn->tn_op)); 2524 } 2525 2526 if (aflag > 0 && 2527 portable_size_in_bits(nt) < portable_size_in_bits(ot) && 2528 (ot == LONG || ot == ULONG || ot == QUAD || ot == UQUAD || 2529 aflag > 1) && 2530 !can_represent(tp, tn)) { 2531 if (op == FARG) { 2532 /* conversion from '%s' to '%s' may lose ... */ 2533 warning(298, 2534 type_name(tn->tn_type), type_name(tp), arg); 2535 } else { 2536 /* conversion from '%s' to '%s' may lose accuracy */ 2537 warning(132, 2538 type_name(tn->tn_type), type_name(tp)); 2539 } 2540 } 2541 2542 if (is_uinteger(nt) != is_uinteger(ot)) 2543 /* implicit conversion changes sign from '%s' to '%s' */ 2544 query_message(3, type_name(tn->tn_type), type_name(tp)); 2545 } 2546 2547 static void 2548 convert_integer_from_pointer(op_t op, tspec_t nt, type_t *tp, tnode_t *tn) 2549 { 2550 2551 if (tn->tn_op == CON) 2552 return; 2553 if (op != CVT) 2554 return; /* We got already an error. */ 2555 if (portable_size_in_bits(nt) >= portable_size_in_bits(PTR)) 2556 return; 2557 2558 if (pflag && size_in_bits(nt) >= size_in_bits(PTR)) { 2559 /* conversion of pointer to '%s' may lose bits */ 2560 warning(134, type_name(tp)); 2561 } else { 2562 /* conversion of pointer to '%s' loses bits */ 2563 warning(133, type_name(tp)); 2564 } 2565 } 2566 2567 static bool 2568 struct_starts_with(const type_t *struct_tp, const type_t *member_tp) 2569 { 2570 2571 return struct_tp->t_str->sou_first_member != NULL && 2572 types_compatible(struct_tp->t_str->sou_first_member->s_type, 2573 member_tp, true, false, NULL); 2574 } 2575 2576 static bool 2577 is_byte_array(const type_t *tp) 2578 { 2579 2580 return tp->t_tspec == ARRAY && 2581 (tp->t_subt->t_tspec == CHAR || tp->t_subt->t_tspec == UCHAR); 2582 } 2583 2584 static bool 2585 should_warn_about_pointer_cast(const type_t *nstp, tspec_t nst, 2586 const type_t *ostp, tspec_t ost) 2587 { 2588 2589 while (nst == ARRAY) 2590 nstp = nstp->t_subt, nst = nstp->t_tspec; 2591 while (ost == ARRAY) 2592 ostp = ostp->t_subt, ost = ostp->t_tspec; 2593 2594 if (nst == STRUCT && ost == STRUCT && 2595 (struct_starts_with(nstp, ostp) || 2596 struct_starts_with(ostp, nstp))) 2597 return false; 2598 2599 if (is_incomplete(nstp) || is_incomplete(ostp)) 2600 return false; 2601 2602 if (nst == CHAR || nst == UCHAR) 2603 return false; /* for the sake of traditional C code */ 2604 if (ost == CHAR || ost == UCHAR) 2605 return false; /* for the sake of traditional C code */ 2606 2607 /* Allow cast between pointers to sockaddr variants. */ 2608 if (nst == STRUCT && ost == STRUCT) { 2609 debug_type(nstp); 2610 debug_type(ostp); 2611 const sym_t *nmem = nstp->t_str->sou_first_member; 2612 const sym_t *omem = ostp->t_str->sou_first_member; 2613 while (nmem != NULL && omem != NULL && 2614 types_compatible(nmem->s_type, omem->s_type, 2615 true, false, NULL)) 2616 nmem = nmem->s_next, omem = omem->s_next; 2617 if (nmem != NULL && is_byte_array(nmem->s_type)) 2618 return false; 2619 if (omem != NULL && is_byte_array(omem->s_type)) 2620 return false; 2621 if (nmem == NULL && omem == NULL) 2622 return false; 2623 } 2624 2625 if (is_struct_or_union(nst) && nstp->t_str != ostp->t_str) 2626 return true; 2627 2628 return portable_size_in_bits(nst) != portable_size_in_bits(ost); 2629 } 2630 2631 static void 2632 convert_pointer_from_pointer(type_t *ntp, tnode_t *tn) 2633 { 2634 const type_t *nstp, *otp, *ostp; 2635 tspec_t nst, ost; 2636 const char *nts, *ots; 2637 2638 nstp = ntp->t_subt; 2639 otp = tn->tn_type; 2640 ostp = otp->t_subt; 2641 nst = nstp->t_tspec; 2642 ost = ostp->t_tspec; 2643 2644 if (nst == VOID || ost == VOID) { 2645 /* TODO: C99 behaves like C90 here. */ 2646 if ((!allow_trad && !allow_c99) && (nst == FUNC || ost == FUNC)) { 2647 /* null pointers are already handled in convert() */ 2648 *(nst == FUNC ? &nts : &ots) = "function pointer"; 2649 *(nst == VOID ? &nts : &ots) = "'void *'"; 2650 /* ANSI C forbids conversion of %s to %s */ 2651 warning(303, ots, nts); 2652 } 2653 return; 2654 } else if (nst == FUNC && ost == FUNC) { 2655 return; 2656 } else if (nst == FUNC || ost == FUNC) { 2657 /* converting '%s' to '%s' is questionable */ 2658 warning(229, type_name(otp), type_name(ntp)); 2659 return; 2660 } 2661 2662 if (hflag && alignment_in_bits(nstp) > alignment_in_bits(ostp) && 2663 ost != CHAR && ost != UCHAR && 2664 !is_incomplete(ostp)) { 2665 /* converting '%s' to '%s' increases alignment ... */ 2666 warning(135, type_name(otp), type_name(ntp), 2667 alignment_in_bits(ostp) / CHAR_SIZE, 2668 alignment_in_bits(nstp) / CHAR_SIZE); 2669 } 2670 2671 if (cflag && should_warn_about_pointer_cast(nstp, nst, ostp, ost)) { 2672 /* pointer cast from '%s' to '%s' may be troublesome */ 2673 warning(247, type_name(otp), type_name(ntp)); 2674 } 2675 } 2676 2677 static void 2678 convert_constant_floating(op_t op, int arg, tspec_t ot, const type_t *tp, 2679 tspec_t nt, val_t *v, val_t *nv) 2680 { 2681 ldbl_t max = 0.0, min = 0.0; 2682 2683 switch (nt) { 2684 case CHAR: 2685 max = TARG_CHAR_MAX; min = TARG_CHAR_MIN; break; 2686 case UCHAR: 2687 max = TARG_UCHAR_MAX; min = 0; break; 2688 case SCHAR: 2689 max = TARG_SCHAR_MAX; min = TARG_SCHAR_MIN; break; 2690 case SHORT: 2691 max = TARG_SHRT_MAX; min = TARG_SHRT_MIN; break; 2692 case USHORT: 2693 max = TARG_USHRT_MAX; min = 0; break; 2694 case ENUM: 2695 case INT: 2696 max = TARG_INT_MAX; min = TARG_INT_MIN; break; 2697 case UINT: 2698 max = TARG_UINT_MAX; min = 0; break; 2699 case LONG: 2700 max = TARG_LONG_MAX; min = TARG_LONG_MIN; break; 2701 case ULONG: 2702 max = TARG_ULONG_MAX; min = 0; break; 2703 case QUAD: 2704 max = QUAD_MAX; min = QUAD_MIN; break; 2705 case UQUAD: 2706 max = UQUAD_MAX; min = 0; break; 2707 case FLOAT: 2708 case FCOMPLEX: 2709 max = FLT_MAX; min = -FLT_MAX; break; 2710 case DOUBLE: 2711 case DCOMPLEX: 2712 max = DBL_MAX; min = -DBL_MAX; break; 2713 case PTR: 2714 /* Got already an error because of float --> ptr */ 2715 case LDOUBLE: 2716 case LCOMPLEX: 2717 /* LINTED 248 */ 2718 max = LDBL_MAX; min = -max; break; 2719 default: 2720 lint_assert(/*CONSTCOND*/false); 2721 } 2722 if (v->v_ldbl > max || v->v_ldbl < min) { 2723 lint_assert(nt != LDOUBLE); 2724 if (op == FARG) { 2725 /* conversion of '%s' to '%s' is out of range, ... */ 2726 warning(295, 2727 type_name(gettyp(ot)), type_name(tp), arg); 2728 } else { 2729 /* conversion of '%s' to '%s' is out of range */ 2730 warning(119, 2731 type_name(gettyp(ot)), type_name(tp)); 2732 } 2733 v->v_ldbl = v->v_ldbl > 0 ? max : min; 2734 } 2735 2736 if (nt == FLOAT) { 2737 nv->v_ldbl = (float)v->v_ldbl; 2738 } else if (nt == DOUBLE) { 2739 nv->v_ldbl = (double)v->v_ldbl; 2740 } else if (nt == LDOUBLE) { 2741 nv->v_ldbl = v->v_ldbl; 2742 } else { 2743 nv->v_quad = (int64_t)v->v_ldbl; 2744 } 2745 } 2746 2747 static bool 2748 convert_constant_to_floating(tspec_t nt, val_t *nv, 2749 tspec_t ot, const val_t *v) 2750 { 2751 if (nt == FLOAT) { 2752 nv->v_ldbl = (ot == PTR || is_uinteger(ot)) ? 2753 (float)(uint64_t)v->v_quad : (float)v->v_quad; 2754 } else if (nt == DOUBLE) { 2755 nv->v_ldbl = (ot == PTR || is_uinteger(ot)) ? 2756 (double)(uint64_t)v->v_quad : (double)v->v_quad; 2757 } else if (nt == LDOUBLE) { 2758 nv->v_ldbl = (ot == PTR || is_uinteger(ot)) ? 2759 (ldbl_t)(uint64_t)v->v_quad : (ldbl_t)v->v_quad; 2760 } else 2761 return false; 2762 return true; 2763 } 2764 2765 /* 2766 * Print a warning if bits which were set are lost due to the conversion. 2767 * This can happen with operator ORASS only. 2768 */ 2769 static void 2770 convert_constant_check_range_bitor(size_t nsz, size_t osz, const val_t *v, 2771 uint64_t xmask, op_t op) 2772 { 2773 if (nsz < osz && (v->v_quad & xmask) != 0) { 2774 /* constant truncated by conversion, op '%s' */ 2775 warning(306, op_name(op)); 2776 } 2777 } 2778 2779 /* 2780 * Print a warning if additional bits are not all 1 2781 * and the most significant bit of the old value is 1, 2782 * or if at least one (but not all) removed bit was 0. 2783 */ 2784 static void 2785 convert_constant_check_range_bitand(size_t nsz, size_t osz, 2786 uint64_t xmask, const val_t *nv, 2787 tspec_t ot, const val_t *v, 2788 const type_t *tp, op_t op) 2789 { 2790 if (nsz > osz && 2791 (nv->v_quad & bit((unsigned int)(osz - 1))) != 0 && 2792 (nv->v_quad & xmask) != xmask) { 2793 /* extra bits set to 0 in conversion of '%s' to '%s', ... */ 2794 warning(309, type_name(gettyp(ot)), 2795 type_name(tp), op_name(op)); 2796 } else if (nsz < osz && 2797 (v->v_quad & xmask) != xmask && 2798 (v->v_quad & xmask) != 0) { 2799 /* constant truncated by conversion, op '%s' */ 2800 warning(306, op_name(op)); 2801 } 2802 } 2803 2804 static void 2805 convert_constant_check_range_signed(op_t op, int arg) 2806 { 2807 if (op == ASSIGN) { 2808 /* assignment of negative constant to unsigned type */ 2809 warning(164); 2810 } else if (op == INIT) { 2811 /* initialization of unsigned with negative constant */ 2812 warning(221); 2813 } else if (op == FARG) { 2814 /* conversion of negative constant to unsigned type, ... */ 2815 warning(296, arg); 2816 } else if (modtab[op].m_comparison) { 2817 /* handled by check_integer_comparison() */ 2818 } else { 2819 /* conversion of negative constant to unsigned type */ 2820 warning(222); 2821 } 2822 } 2823 2824 /* 2825 * Loss of significant bit(s). All truncated bits 2826 * of unsigned types or all truncated bits plus the 2827 * msb of the target for signed types are considered 2828 * to be significant bits. Loss of significant bits 2829 * means that at least one of the bits was set in an 2830 * unsigned type or that at least one but not all of 2831 * the bits was set in a signed type. 2832 * Loss of significant bits means that it is not 2833 * possible, also not with necessary casts, to convert 2834 * back to the original type. A example for a 2835 * necessary cast is: 2836 * char c; int i; c = 128; 2837 * i = c; ** yields -128 ** 2838 * i = (unsigned char)c; ** yields 128 ** 2839 */ 2840 static void 2841 convert_constant_check_range_truncated(op_t op, int arg, const type_t *tp, 2842 tspec_t ot) 2843 { 2844 if (op == ASSIGN && tp->t_bitfield) { 2845 /* precision lost in bit-field assignment */ 2846 warning(166); 2847 } else if (op == ASSIGN) { 2848 /* constant truncated by assignment */ 2849 warning(165); 2850 } else if (op == INIT && tp->t_bitfield) { 2851 /* bit-field initializer does not fit */ 2852 warning(180); 2853 } else if (op == INIT) { 2854 /* initializer does not fit */ 2855 warning(178); 2856 } else if (op == CASE) { 2857 /* case label affected by conversion */ 2858 warning(196); 2859 } else if (op == FARG) { 2860 /* conversion of '%s' to '%s' is out of range, arg #%d */ 2861 warning(295, 2862 type_name(gettyp(ot)), type_name(tp), arg); 2863 } else { 2864 /* conversion of '%s' to '%s' is out of range */ 2865 warning(119, 2866 type_name(gettyp(ot)), type_name(tp)); 2867 } 2868 } 2869 2870 static void 2871 convert_constant_check_range_loss(op_t op, int arg, const type_t *tp, 2872 tspec_t ot) 2873 { 2874 if (op == ASSIGN && tp->t_bitfield) { 2875 /* precision lost in bit-field assignment */ 2876 warning(166); 2877 } else if (op == INIT && tp->t_bitfield) { 2878 /* bit-field initializer out of range */ 2879 warning(11); 2880 } else if (op == CASE) { 2881 /* case label affected by conversion */ 2882 warning(196); 2883 } else if (op == FARG) { 2884 /* conversion of '%s' to '%s' is out of range, arg #%d */ 2885 warning(295, 2886 type_name(gettyp(ot)), type_name(tp), arg); 2887 } else { 2888 /* conversion of '%s' to '%s' is out of range */ 2889 warning(119, 2890 type_name(gettyp(ot)), type_name(tp)); 2891 } 2892 } 2893 2894 static void 2895 convert_constant_check_range(tspec_t ot, const type_t *tp, tspec_t nt, 2896 op_t op, int arg, const val_t *v, val_t *nv) 2897 { 2898 unsigned int obitsz, nbitsz; 2899 uint64_t xmask, xmsk1; 2900 2901 obitsz = size_in_bits(ot); 2902 nbitsz = tp->t_bitfield ? tp->t_flen : size_in_bits(nt); 2903 xmask = value_bits(nbitsz) ^ value_bits(obitsz); 2904 xmsk1 = value_bits(nbitsz) ^ value_bits(obitsz - 1); 2905 /* 2906 * For bitwise operations we are not interested in the arithmetic 2907 * value, but in the bits itself. 2908 */ 2909 if (op == ORASS || op == BITOR || op == BITXOR) { 2910 convert_constant_check_range_bitor( 2911 nbitsz, obitsz, v, xmask, op); 2912 } else if (op == ANDASS || op == BITAND) { 2913 convert_constant_check_range_bitand( 2914 nbitsz, obitsz, xmask, nv, ot, v, tp, op); 2915 } else if ((nt != PTR && is_uinteger(nt)) && 2916 (ot != PTR && !is_uinteger(ot)) && 2917 v->v_quad < 0) { 2918 convert_constant_check_range_signed(op, arg); 2919 } else if (nv->v_quad != v->v_quad && nbitsz <= obitsz && 2920 (v->v_quad & xmask) != 0 && 2921 (is_uinteger(ot) || (v->v_quad & xmsk1) != xmsk1)) { 2922 convert_constant_check_range_truncated(op, arg, tp, ot); 2923 } else if (nv->v_quad != v->v_quad) { 2924 convert_constant_check_range_loss(op, arg, tp, ot); 2925 } 2926 } 2927 2928 /* 2929 * Converts a typed constant to a constant of another type. 2930 * 2931 * op operator which requires conversion 2932 * arg if op is FARG, # of argument 2933 * tp type in which to convert the constant 2934 * nv new constant 2935 * v old constant 2936 */ 2937 void 2938 convert_constant(op_t op, int arg, const type_t *tp, val_t *nv, val_t *v) 2939 { 2940 tspec_t ot, nt; 2941 unsigned int sz; 2942 bool range_check; 2943 2944 /* 2945 * TODO: make 'v' const; the name of this function does not suggest 2946 * that it modifies 'v'. 2947 */ 2948 ot = v->v_tspec; 2949 nt = nv->v_tspec = tp->t_tspec; 2950 range_check = false; 2951 2952 if (nt == BOOL) { /* C99 6.3.1.2 */ 2953 nv->v_unsigned_since_c90 = false; 2954 nv->v_quad = is_nonzero_val(v) ? 1 : 0; 2955 return; 2956 } 2957 2958 if (ot == FLOAT || ot == DOUBLE || ot == LDOUBLE) { 2959 convert_constant_floating(op, arg, ot, tp, nt, v, nv); 2960 } else if (!convert_constant_to_floating(nt, nv, ot, v)) { 2961 range_check = true; /* Check for lost precision. */ 2962 nv->v_quad = v->v_quad; 2963 } 2964 2965 if (allow_trad && allow_c90 && v->v_unsigned_since_c90 && 2966 (is_floating(nt) || ( 2967 (is_integer(nt) && !is_uinteger(nt) && 2968 portable_size_in_bits(nt) > portable_size_in_bits(ot))))) { 2969 /* ANSI C treats constant as unsigned */ 2970 warning(157); 2971 v->v_unsigned_since_c90 = false; 2972 } 2973 2974 if (is_integer(nt)) { 2975 sz = tp->t_bitfield ? tp->t_flen : size_in_bits(nt); 2976 nv->v_quad = convert_integer(nv->v_quad, nt, sz); 2977 } 2978 2979 if (range_check && op != CVT) 2980 convert_constant_check_range(ot, tp, nt, op, arg, v, nv); 2981 } 2982 2983 /* 2984 * Called if incompatible types were detected. 2985 * Prints a appropriate warning. 2986 */ 2987 static void 2988 warn_incompatible_types(op_t op, 2989 const type_t *ltp, tspec_t lt, 2990 const type_t *rtp, tspec_t rt) 2991 { 2992 const mod_t *mp; 2993 2994 mp = &modtab[op]; 2995 2996 if (lt == VOID || (mp->m_binary && rt == VOID)) { 2997 /* void type illegal in expression */ 2998 error(109); 2999 } else if (op == ASSIGN) { 3000 /* cannot assign to '%s' from '%s' */ 3001 error(171, type_name(ltp), type_name(rtp)); 3002 } else if (mp->m_binary) { 3003 /* operands of '%s' have incompatible types '%s' and '%s' */ 3004 error(107, mp->m_name, tspec_name(lt), tspec_name(rt)); 3005 } else { 3006 lint_assert(rt == NOTSPEC); 3007 /* operand of '%s' has invalid type '%s' */ 3008 error(108, mp->m_name, type_name(ltp)); 3009 } 3010 } 3011 3012 /* 3013 * Called if incompatible pointer types are detected. 3014 * Print an appropriate warning. 3015 */ 3016 static void 3017 warn_incompatible_pointers(const mod_t *mp, 3018 const type_t *ltp, const type_t *rtp) 3019 { 3020 tspec_t lt, rt; 3021 3022 lint_assert(ltp->t_tspec == PTR); 3023 lint_assert(rtp->t_tspec == PTR); 3024 3025 lt = ltp->t_subt->t_tspec; 3026 rt = rtp->t_subt->t_tspec; 3027 3028 if (is_struct_or_union(lt) && is_struct_or_union(rt)) { 3029 if (mp == NULL) { 3030 /* illegal structure pointer combination */ 3031 warning(244); 3032 } else { 3033 /* incompatible structure pointers: '%s' '%s' '%s' */ 3034 warning(245, type_name(ltp), mp->m_name, type_name(rtp)); 3035 } 3036 } else { 3037 if (mp == NULL) { 3038 /* illegal combination of '%s' and '%s' */ 3039 warning(184, type_name(ltp), type_name(rtp)); 3040 } else { 3041 /* illegal combination of '%s' and '%s', op '%s' */ 3042 warning(124, 3043 type_name(ltp), type_name(rtp), mp->m_name); 3044 } 3045 } 3046 } 3047 3048 /* Return a type based on tp1, with added qualifiers from tp2. */ 3049 static type_t * 3050 merge_qualifiers(type_t *tp1, const type_t *tp2) 3051 { 3052 type_t *ntp, *nstp; 3053 bool c1, c2, v1, v2; 3054 3055 lint_assert(tp1->t_tspec == PTR); 3056 lint_assert(tp2->t_tspec == PTR); 3057 3058 c1 = tp1->t_subt->t_const; 3059 c2 = tp2->t_subt->t_const; 3060 v1 = tp1->t_subt->t_volatile; 3061 v2 = tp2->t_subt->t_volatile; 3062 3063 if (c1 == (c1 | c2) && v1 == (v1 | v2)) 3064 return tp1; 3065 3066 nstp = expr_dup_type(tp1->t_subt); 3067 nstp->t_const |= c2; 3068 nstp->t_volatile |= v2; 3069 3070 ntp = expr_dup_type(tp1); 3071 ntp->t_subt = nstp; 3072 return ntp; 3073 } 3074 3075 /* 3076 * Returns true if the given structure or union has a constant member 3077 * (maybe recursively). 3078 */ 3079 static bool 3080 has_constant_member(const type_t *tp) 3081 { 3082 sym_t *m; 3083 3084 lint_assert(is_struct_or_union(tp->t_tspec)); 3085 3086 for (m = tp->t_str->sou_first_member; m != NULL; m = m->s_next) { 3087 const type_t *mtp = m->s_type; 3088 if (mtp->t_const) 3089 return true; 3090 if (is_struct_or_union(mtp->t_tspec) && 3091 has_constant_member(mtp)) 3092 return true; 3093 } 3094 return false; 3095 } 3096 3097 /* 3098 * Create a new node for one of the operators POINT and ARROW. 3099 */ 3100 static tnode_t * 3101 build_struct_access(op_t op, bool sys, tnode_t *ln, tnode_t *rn) 3102 { 3103 tnode_t *ntn, *ctn; 3104 bool nolval; 3105 3106 lint_assert(rn->tn_op == NAME); 3107 lint_assert(is_member(rn->tn_sym)); 3108 3109 /* 3110 * Remember if the left operand is an lvalue (structure members 3111 * are lvalues if and only if the structure itself is an lvalue). 3112 */ 3113 nolval = op == POINT && !ln->tn_lvalue; 3114 3115 if (op == POINT) { 3116 ln = build_address(sys, ln, true); 3117 } else if (ln->tn_type->t_tspec != PTR) { 3118 lint_assert(!allow_c90); 3119 lint_assert(is_integer(ln->tn_type->t_tspec)); 3120 ln = convert(NOOP, 0, expr_derive_type(gettyp(VOID), PTR), ln); 3121 } 3122 3123 ctn = build_integer_constant(PTRDIFF_TSPEC, 3124 rn->tn_sym->u.s_member.sm_offset_in_bits / CHAR_SIZE); 3125 3126 ntn = new_tnode(PLUS, sys, expr_derive_type(rn->tn_type, PTR), 3127 ln, ctn); 3128 if (ln->tn_op == CON) 3129 ntn = fold(ntn); 3130 3131 if (rn->tn_type->t_bitfield) { 3132 ntn = new_tnode(FSEL, sys, ntn->tn_type->t_subt, ntn, NULL); 3133 } else { 3134 ntn = new_tnode(INDIR, sys, ntn->tn_type->t_subt, ntn, NULL); 3135 } 3136 3137 if (nolval) 3138 ntn->tn_lvalue = false; 3139 3140 return ntn; 3141 } 3142 3143 /* 3144 * Create a node for INCAFT, INCBEF, DECAFT and DECBEF. 3145 */ 3146 static tnode_t * 3147 build_prepost_incdec(op_t op, bool sys, tnode_t *ln) 3148 { 3149 tnode_t *cn, *ntn; 3150 3151 lint_assert(ln != NULL); 3152 3153 if (ln->tn_type->t_tspec == PTR) { 3154 cn = subt_size_in_bytes(ln->tn_type); 3155 } else { 3156 cn = build_integer_constant(INT, (int64_t)1); 3157 } 3158 ntn = new_tnode(op, sys, ln->tn_type, ln, cn); 3159 3160 return ntn; 3161 } 3162 3163 /* 3164 * Create a node for REAL, IMAG 3165 */ 3166 static tnode_t * 3167 build_real_imag(op_t op, bool sys, tnode_t *ln) 3168 { 3169 tnode_t *cn, *ntn; 3170 3171 lint_assert(ln != NULL); 3172 3173 if (ln->tn_op == NAME) { 3174 /* 3175 * This may be too much, but it avoids wrong warnings. 3176 * See d_c99_complex_split.c. 3177 */ 3178 mark_as_used(ln->tn_sym, false, false); 3179 mark_as_set(ln->tn_sym); 3180 } 3181 3182 switch (ln->tn_type->t_tspec) { 3183 case LCOMPLEX: 3184 /* XXX: integer and LDOUBLE don't match. */ 3185 cn = build_integer_constant(LDOUBLE, (int64_t)1); 3186 break; 3187 case DCOMPLEX: 3188 /* XXX: integer and DOUBLE don't match. */ 3189 cn = build_integer_constant(DOUBLE, (int64_t)1); 3190 break; 3191 case FCOMPLEX: 3192 /* XXX: integer and FLOAT don't match. */ 3193 cn = build_integer_constant(FLOAT, (int64_t)1); 3194 break; 3195 default: 3196 /* '__%s__' is illegal for type '%s' */ 3197 error(276, op == REAL ? "real" : "imag", 3198 type_name(ln->tn_type)); 3199 return NULL; 3200 } 3201 ntn = new_tnode(op, sys, cn->tn_type, ln, cn); 3202 ntn->tn_lvalue = true; 3203 3204 return ntn; 3205 } 3206 3207 /* 3208 * Create a tree node for the unary & operator 3209 */ 3210 static tnode_t * 3211 build_address(bool sys, tnode_t *tn, bool noign) 3212 { 3213 tspec_t t; 3214 3215 if (!noign && ((t = tn->tn_type->t_tspec) == ARRAY || t == FUNC)) { 3216 if (!allow_c90) 3217 /* '&' before array or function: ignored */ 3218 warning(127); 3219 return tn; 3220 } 3221 3222 /* eliminate &* */ 3223 if (tn->tn_op == INDIR && 3224 tn->tn_left->tn_type->t_tspec == PTR && 3225 tn->tn_left->tn_type->t_subt == tn->tn_type) { 3226 return tn->tn_left; 3227 } 3228 3229 return new_tnode(ADDR, sys, expr_derive_type(tn->tn_type, PTR), 3230 tn, NULL); 3231 } 3232 3233 /* 3234 * Create a node for operators PLUS and MINUS. 3235 */ 3236 static tnode_t * 3237 build_plus_minus(op_t op, bool sys, tnode_t *ln, tnode_t *rn) 3238 { 3239 3240 /* If pointer and integer, then pointer to the lhs. */ 3241 if (rn->tn_type->t_tspec == PTR && is_integer(ln->tn_type->t_tspec)) { 3242 tnode_t *tmp = ln; 3243 ln = rn; 3244 rn = tmp; 3245 /* pointer addition has integer on the left-hand side */ 3246 query_message(5); 3247 } 3248 3249 /* pointer +- integer */ 3250 if (ln->tn_type->t_tspec == PTR && rn->tn_type->t_tspec != PTR) { 3251 lint_assert(is_integer(rn->tn_type->t_tspec)); 3252 3253 check_ctype_macro_invocation(ln, rn); 3254 check_enum_array_index(ln, rn); 3255 3256 tnode_t *elsz = subt_size_in_bytes(ln->tn_type); 3257 if (rn->tn_type->t_tspec != elsz->tn_type->t_tspec) 3258 rn = convert(NOOP, 0, elsz->tn_type, rn); 3259 3260 tnode_t *prod = new_tnode(MULT, sys, rn->tn_type, rn, elsz); 3261 if (rn->tn_op == CON) 3262 prod = fold(prod); 3263 3264 return new_tnode(op, sys, ln->tn_type, ln, prod); 3265 } 3266 3267 /* pointer - pointer */ 3268 if (rn->tn_type->t_tspec == PTR) { 3269 lint_assert(ln->tn_type->t_tspec == PTR); 3270 lint_assert(op == MINUS); 3271 3272 type_t *ptrdiff = gettyp(PTRDIFF_TSPEC); 3273 tnode_t *raw_diff = new_tnode(op, sys, ptrdiff, ln, rn); 3274 if (ln->tn_op == CON && rn->tn_op == CON) 3275 raw_diff = fold(raw_diff); 3276 3277 tnode_t *elsz = subt_size_in_bytes(ln->tn_type); 3278 balance(NOOP, &raw_diff, &elsz); 3279 3280 return new_tnode(DIV, sys, ptrdiff, raw_diff, elsz); 3281 } 3282 3283 return new_tnode(op, sys, ln->tn_type, ln, rn); 3284 } 3285 3286 /* 3287 * Create a node for operators SHL and SHR. 3288 */ 3289 static tnode_t * 3290 build_bit_shift(op_t op, bool sys, tnode_t *ln, tnode_t *rn) 3291 { 3292 3293 if (!allow_c90 && rn->tn_type->t_tspec != INT) 3294 rn = convert(NOOP, 0, gettyp(INT), rn); 3295 return new_tnode(op, sys, ln->tn_type, ln, rn); 3296 } 3297 3298 /* See C99 6.5.15 "Conditional operator". */ 3299 static tnode_t * 3300 build_colon(bool sys, tnode_t *ln, tnode_t *rn) 3301 { 3302 tspec_t lt, rt; 3303 type_t *tp; 3304 3305 lt = ln->tn_type->t_tspec; 3306 rt = rn->tn_type->t_tspec; 3307 3308 if (is_arithmetic(lt) && is_arithmetic(rt)) { 3309 /* The operands were already balanced in build_binary. */ 3310 tp = ln->tn_type; 3311 } else if (lt == BOOL && rt == BOOL) { 3312 tp = ln->tn_type; 3313 } else if (lt == VOID || rt == VOID) { 3314 tp = gettyp(VOID); 3315 } else if (is_struct_or_union(lt)) { 3316 /* Both types must be identical. */ 3317 lint_assert(is_struct_or_union(rt)); 3318 lint_assert(ln->tn_type->t_str == rn->tn_type->t_str); 3319 if (is_incomplete(ln->tn_type)) { 3320 /* unknown operand size, op '%s' */ 3321 error(138, op_name(COLON)); 3322 return NULL; 3323 } 3324 tp = ln->tn_type; 3325 } else if (lt == PTR && is_integer(rt)) { 3326 if (rt != PTRDIFF_TSPEC) 3327 rn = convert(NOOP, 0, gettyp(PTRDIFF_TSPEC), rn); 3328 tp = ln->tn_type; 3329 } else if (rt == PTR && is_integer(lt)) { 3330 if (lt != PTRDIFF_TSPEC) 3331 ln = convert(NOOP, 0, gettyp(PTRDIFF_TSPEC), ln); 3332 tp = rn->tn_type; 3333 } else if (lt == PTR && is_null_pointer(rn)) { 3334 tp = merge_qualifiers(ln->tn_type, rn->tn_type); 3335 } else if (rt == PTR && is_null_pointer(ln)) { 3336 tp = merge_qualifiers(rn->tn_type, ln->tn_type); 3337 } else if (lt == PTR && ln->tn_type->t_subt->t_tspec == VOID) { 3338 tp = merge_qualifiers(ln->tn_type, rn->tn_type); 3339 } else if (rt == PTR && rn->tn_type->t_subt->t_tspec == VOID) { 3340 tp = merge_qualifiers(rn->tn_type, ln->tn_type); 3341 } else { 3342 /* 3343 * XXX For now we simply take the left type. This is 3344 * probably wrong, if one type contains a function prototype 3345 * and the other one, at the same place, only an old-style 3346 * declaration. 3347 */ 3348 tp = merge_qualifiers(ln->tn_type, rn->tn_type); 3349 } 3350 3351 return new_tnode(COLON, sys, tp, ln, rn); 3352 } 3353 3354 /* TODO: check for varargs */ 3355 static bool 3356 is_cast_redundant(const tnode_t *tn) 3357 { 3358 const type_t *ntp = tn->tn_type, *otp = tn->tn_left->tn_type; 3359 tspec_t nt = ntp->t_tspec, ot = otp->t_tspec; 3360 3361 if (nt == BOOL || ot == BOOL) 3362 return nt == BOOL && ot == BOOL; 3363 3364 if (is_integer(nt) && is_integer(ot)) { 3365 unsigned int nw = width_in_bits(ntp), ow = width_in_bits(otp); 3366 if (is_uinteger(nt) == is_uinteger(ot)) 3367 return nw >= ow; 3368 return is_uinteger(ot) && nw > ow; 3369 } 3370 3371 if (is_complex(nt) || is_complex(ot)) 3372 return is_complex(nt) && is_complex(ot) && 3373 size_in_bits(nt) >= size_in_bits(ot); 3374 3375 if (is_floating(nt) && is_floating(ot)) 3376 return size_in_bits(nt) >= size_in_bits(ot); 3377 3378 if (nt == PTR && ot == PTR) { 3379 if (!ntp->t_subt->t_const && otp->t_subt->t_const) 3380 return false; 3381 if (!ntp->t_subt->t_volatile && otp->t_subt->t_volatile) 3382 return false; 3383 3384 if (ntp->t_subt->t_tspec == VOID || 3385 otp->t_subt->t_tspec == VOID || 3386 types_compatible(ntp->t_subt, otp->t_subt, 3387 false, false, NULL)) 3388 return true; 3389 } 3390 3391 return false; 3392 } 3393 3394 /* 3395 * Create a node for an assignment operator (both = and op= ). 3396 */ 3397 static tnode_t * 3398 build_assignment(op_t op, bool sys, tnode_t *ln, tnode_t *rn) 3399 { 3400 tspec_t lt, rt; 3401 tnode_t *ntn, *ctn; 3402 3403 lint_assert(ln != NULL); 3404 lint_assert(rn != NULL); 3405 3406 lt = ln->tn_type->t_tspec; 3407 rt = rn->tn_type->t_tspec; 3408 3409 if ((op == ADDASS || op == SUBASS) && lt == PTR) { 3410 lint_assert(is_integer(rt)); 3411 ctn = subt_size_in_bytes(ln->tn_type); 3412 if (rn->tn_type->t_tspec != ctn->tn_type->t_tspec) 3413 rn = convert(NOOP, 0, ctn->tn_type, rn); 3414 rn = new_tnode(MULT, sys, rn->tn_type, rn, ctn); 3415 if (rn->tn_left->tn_op == CON) 3416 rn = fold(rn); 3417 } 3418 3419 if ((op == ASSIGN || op == RETURN || op == INIT) && 3420 (lt == STRUCT || rt == STRUCT)) { 3421 lint_assert(lt == rt); 3422 lint_assert(ln->tn_type->t_str == rn->tn_type->t_str); 3423 if (is_incomplete(ln->tn_type)) { 3424 if (op == RETURN) { 3425 /* cannot return incomplete type */ 3426 error(212); 3427 } else { 3428 /* unknown operand size, op '%s' */ 3429 error(138, op_name(op)); 3430 } 3431 return NULL; 3432 } 3433 } 3434 3435 if (op == SHLASS) { 3436 if (portable_size_in_bits(lt) < portable_size_in_bits(rt)) { 3437 if (hflag) 3438 /* semantics of '%s' change in ANSI C; ... */ 3439 warning(118, "<<="); 3440 } 3441 } else if (op != SHRASS) { 3442 if (op == ASSIGN || lt != PTR) { 3443 if (lt != rt || 3444 (ln->tn_type->t_bitfield && rn->tn_op == CON)) { 3445 rn = convert(op, 0, ln->tn_type, rn); 3446 rt = lt; 3447 } 3448 } 3449 } 3450 3451 if (any_query_enabled && rn->tn_op == CVT && rn->tn_cast && 3452 types_compatible(ln->tn_type, rn->tn_type, false, false, NULL) && 3453 is_cast_redundant(rn)) { 3454 /* redundant cast from '%s' to '%s' before assignment */ 3455 query_message(7, 3456 type_name(rn->tn_left->tn_type), type_name(rn->tn_type)); 3457 } 3458 3459 ntn = new_tnode(op, sys, ln->tn_type, ln, rn); 3460 3461 return ntn; 3462 } 3463 3464 /* 3465 * Get the size in bytes of type tp->t_subt, as a constant expression of type 3466 * ptrdiff_t as seen from the target platform. 3467 */ 3468 static tnode_t * 3469 subt_size_in_bytes(type_t *tp) 3470 { 3471 int elem, elsz_in_bits; 3472 3473 lint_assert(tp->t_tspec == PTR); 3474 tp = tp->t_subt; 3475 3476 elem = 1; 3477 elsz_in_bits = 0; 3478 3479 while (tp->t_tspec == ARRAY) { 3480 elem *= tp->t_dim; 3481 tp = tp->t_subt; 3482 } 3483 3484 switch (tp->t_tspec) { 3485 case FUNC: 3486 /* pointer to function is not allowed here */ 3487 error(110); 3488 break; 3489 case VOID: 3490 /* cannot do pointer arithmetic on operand of unknown size */ 3491 gnuism(136); 3492 break; 3493 case STRUCT: 3494 case UNION: 3495 if ((elsz_in_bits = tp->t_str->sou_size_in_bits) == 0) 3496 /* cannot do pointer arithmetic on operand of ... */ 3497 error(136); 3498 break; 3499 case ENUM: 3500 if (is_incomplete(tp)) { 3501 /* cannot do pointer arithmetic on operand of ... */ 3502 warning(136); 3503 } 3504 /* FALLTHROUGH */ 3505 default: 3506 if ((elsz_in_bits = size_in_bits(tp->t_tspec)) == 0) { 3507 /* cannot do pointer arithmetic on operand of ... */ 3508 error(136); 3509 } else { 3510 lint_assert(elsz_in_bits != -1); 3511 } 3512 break; 3513 } 3514 3515 if (elem == 0 && elsz_in_bits != 0) { 3516 /* cannot do pointer arithmetic on operand of unknown size */ 3517 error(136); 3518 } 3519 3520 if (elsz_in_bits == 0) 3521 elsz_in_bits = CHAR_SIZE; 3522 3523 return build_integer_constant(PTRDIFF_TSPEC, 3524 (int64_t)(elem * elsz_in_bits / CHAR_SIZE)); 3525 } 3526 3527 /* 3528 * XXX 3529 * Note: There appear to be a number of bugs in detecting overflow in 3530 * this function. An audit and a set of proper regression tests are needed. 3531 * --Perry Metzger, Nov. 16, 2001 3532 */ 3533 /* 3534 * Do only as much as necessary to compute constant expressions. 3535 * Called only if the operator allows folding and all operands are constants. 3536 */ 3537 static tnode_t * 3538 fold(tnode_t *tn) 3539 { 3540 val_t *v; 3541 tspec_t t; 3542 bool utyp, ovfl; 3543 int64_t sl, sr = 0, q = 0, mask; 3544 uint64_t ul, ur = 0; 3545 tnode_t *cn; 3546 3547 v = xcalloc(1, sizeof(*v)); 3548 v->v_tspec = tn->tn_type->t_tspec; 3549 3550 t = tn->tn_left->tn_type->t_tspec; 3551 utyp = !is_integer(t) || is_uinteger(t); 3552 ul = sl = tn->tn_left->tn_val->v_quad; 3553 if (is_binary(tn)) 3554 ur = sr = tn->tn_right->tn_val->v_quad; 3555 3556 mask = value_bits(size_in_bits(t)); 3557 ovfl = false; 3558 3559 switch (tn->tn_op) { 3560 case UPLUS: 3561 q = sl; 3562 break; 3563 case UMINUS: 3564 q = sl == INT64_MIN ? sl : -sl; 3565 if (sl != 0 && msb(q, t) == msb(sl, t)) 3566 ovfl = true; 3567 break; 3568 case COMPL: 3569 q = ~sl; 3570 break; 3571 case MULT: 3572 if (utyp) { 3573 q = ul * ur; 3574 if (q != (q & mask)) 3575 ovfl = true; 3576 else if ((ul != 0) && ((q / ul) != ur)) 3577 ovfl = true; 3578 } else { 3579 q = sl * sr; 3580 if (msb(q, t) != (msb(sl, t) ^ msb(sr, t))) 3581 ovfl = true; 3582 } 3583 break; 3584 case DIV: 3585 if (sr == 0) { 3586 /* division by 0 */ 3587 error(139); 3588 q = utyp ? -1 : INT64_MAX; 3589 } else { 3590 q = utyp ? (int64_t)(ul / ur) : sl / sr; 3591 } 3592 break; 3593 case MOD: 3594 if (sr == 0) { 3595 /* modulus by 0 */ 3596 error(140); 3597 q = 0; 3598 } else { 3599 q = utyp ? (int64_t)(ul % ur) : sl % sr; 3600 } 3601 break; 3602 case PLUS: 3603 q = utyp ? (int64_t)(ul + ur) : sl + sr; 3604 if (msb(sl, t) && msb(sr, t) && !msb(q, t)) 3605 ovfl = true; 3606 if (!utyp && !msb(sl, t) && !msb(sr, t) && msb(q, t)) 3607 ovfl = true; 3608 break; 3609 case MINUS: 3610 q = utyp ? (int64_t)(ul - ur) : sl - sr; 3611 if (!utyp && msb(sl, t) && !msb(sr, t) && !msb(q, t)) 3612 ovfl = true; 3613 if (!msb(sl, t) && msb(sr, t) && msb(q, t)) 3614 ovfl = true; 3615 break; 3616 case SHL: 3617 /* TODO: warn about out-of-bounds 'sr'. */ 3618 q = utyp ? (int64_t)(ul << (sr & 63)) : sl << (sr & 63); 3619 break; 3620 case SHR: 3621 /* 3622 * The sign must be explicitly extended because 3623 * shifts of signed values are implementation dependent. 3624 */ 3625 /* TODO: warn about out-of-bounds 'sr'. */ 3626 q = ul >> (sr & 63); 3627 q = convert_integer(q, t, size_in_bits(t) - (int)sr); 3628 break; 3629 case LT: 3630 q = (utyp ? ul < ur : sl < sr) ? 1 : 0; 3631 break; 3632 case LE: 3633 q = (utyp ? ul <= ur : sl <= sr) ? 1 : 0; 3634 break; 3635 case GE: 3636 q = (utyp ? ul >= ur : sl >= sr) ? 1 : 0; 3637 break; 3638 case GT: 3639 q = (utyp ? ul > ur : sl > sr) ? 1 : 0; 3640 break; 3641 case EQ: 3642 q = (utyp ? ul == ur : sl == sr) ? 1 : 0; 3643 break; 3644 case NE: 3645 q = (utyp ? ul != ur : sl != sr) ? 1 : 0; 3646 break; 3647 case BITAND: 3648 q = utyp ? (int64_t)(ul & ur) : sl & sr; 3649 break; 3650 case BITXOR: 3651 q = utyp ? (int64_t)(ul ^ ur) : sl ^ sr; 3652 break; 3653 case BITOR: 3654 q = utyp ? (int64_t)(ul | ur) : sl | sr; 3655 break; 3656 default: 3657 lint_assert(/*CONSTCOND*/false); 3658 } 3659 3660 /* XXX does not work for quads. */ 3661 if (ovfl || 3662 ((uint64_t)(q | mask) != ~(uint64_t)0 && (q & ~mask) != 0)) { 3663 if (hflag) 3664 /* integer overflow detected, op '%s' */ 3665 warning(141, op_name(tn->tn_op)); 3666 } 3667 3668 v->v_quad = convert_integer(q, t, 0); 3669 3670 cn = build_constant(tn->tn_type, v); 3671 if (tn->tn_left->tn_system_dependent) 3672 cn->tn_system_dependent = true; 3673 if (is_binary(tn) && tn->tn_right->tn_system_dependent) 3674 cn->tn_system_dependent = true; 3675 3676 return cn; 3677 } 3678 3679 /* 3680 * Fold constant nodes, as much as is needed for comparing the value with 0. 3681 */ 3682 static tnode_t * 3683 fold_bool(tnode_t *tn) 3684 { 3685 bool l, r; 3686 val_t *v; 3687 3688 v = xcalloc(1, sizeof(*v)); 3689 v->v_tspec = tn->tn_type->t_tspec; 3690 lint_assert(v->v_tspec == INT || (Tflag && v->v_tspec == BOOL)); 3691 3692 l = constant_is_nonzero(tn->tn_left); 3693 r = is_binary(tn) && constant_is_nonzero(tn->tn_right); 3694 3695 switch (tn->tn_op) { 3696 case NOT: 3697 if (hflag && !constcond_flag) 3698 /* constant argument to '!' */ 3699 warning(239); 3700 v->v_quad = !l ? 1 : 0; 3701 break; 3702 case LOGAND: 3703 v->v_quad = l && r ? 1 : 0; 3704 break; 3705 case LOGOR: 3706 v->v_quad = l || r ? 1 : 0; 3707 break; 3708 default: 3709 lint_assert(/*CONSTCOND*/false); 3710 } 3711 3712 return build_constant(tn->tn_type, v); 3713 } 3714 3715 static ldbl_t 3716 floating_error_value(tspec_t t, ldbl_t lv) 3717 { 3718 if (t == FLOAT) { 3719 return lv < 0 ? -FLT_MAX : FLT_MAX; 3720 } else if (t == DOUBLE) { 3721 return lv < 0 ? -DBL_MAX : DBL_MAX; 3722 } else { 3723 /* LINTED 248: floating-point constant out of range */ 3724 ldbl_t max = LDBL_MAX; 3725 return lv < 0 ? -max : max; 3726 } 3727 } 3728 3729 /* 3730 * Fold constant nodes having operands with floating point type. 3731 */ 3732 static tnode_t * 3733 fold_float(tnode_t *tn) 3734 { 3735 val_t *v; 3736 tspec_t t; 3737 ldbl_t lv, rv = 0; 3738 3739 fpe = 0; 3740 v = xcalloc(1, sizeof(*v)); 3741 v->v_tspec = t = tn->tn_type->t_tspec; 3742 3743 lint_assert(is_floating(t)); 3744 lint_assert(t == tn->tn_left->tn_type->t_tspec); 3745 lint_assert(!is_binary(tn) || t == tn->tn_right->tn_type->t_tspec); 3746 3747 lv = tn->tn_left->tn_val->v_ldbl; 3748 if (is_binary(tn)) 3749 rv = tn->tn_right->tn_val->v_ldbl; 3750 3751 switch (tn->tn_op) { 3752 case UPLUS: 3753 v->v_ldbl = lv; 3754 break; 3755 case UMINUS: 3756 v->v_ldbl = -lv; 3757 break; 3758 case MULT: 3759 v->v_ldbl = lv * rv; 3760 break; 3761 case DIV: 3762 if (rv == 0.0) { 3763 /* division by 0 */ 3764 error(139); 3765 v->v_ldbl = floating_error_value(t, lv); 3766 } else { 3767 v->v_ldbl = lv / rv; 3768 } 3769 break; 3770 case PLUS: 3771 v->v_ldbl = lv + rv; 3772 break; 3773 case MINUS: 3774 v->v_ldbl = lv - rv; 3775 break; 3776 case LT: 3777 v->v_quad = lv < rv ? 1 : 0; 3778 break; 3779 case LE: 3780 v->v_quad = lv <= rv ? 1 : 0; 3781 break; 3782 case GE: 3783 v->v_quad = lv >= rv ? 1 : 0; 3784 break; 3785 case GT: 3786 v->v_quad = lv > rv ? 1 : 0; 3787 break; 3788 case EQ: 3789 v->v_quad = lv == rv ? 1 : 0; 3790 break; 3791 case NE: 3792 v->v_quad = lv != rv ? 1 : 0; 3793 break; 3794 default: 3795 lint_assert(/*CONSTCOND*/false); 3796 } 3797 3798 lint_assert(fpe != 0 || isnan((double)v->v_ldbl) == 0); 3799 if (fpe != 0 || isfinite((double)v->v_ldbl) == 0 || 3800 (t == FLOAT && 3801 (v->v_ldbl > FLT_MAX || v->v_ldbl < -FLT_MAX)) || 3802 (t == DOUBLE && 3803 (v->v_ldbl > DBL_MAX || v->v_ldbl < -DBL_MAX))) { 3804 /* floating point overflow on operator '%s' */ 3805 warning(142, op_name(tn->tn_op)); 3806 v->v_ldbl = floating_error_value(t, v->v_ldbl); 3807 fpe = 0; 3808 } 3809 3810 return build_constant(tn->tn_type, v); 3811 } 3812 3813 3814 /* 3815 * Create a constant node for sizeof. 3816 */ 3817 tnode_t * 3818 build_sizeof(const type_t *tp) 3819 { 3820 unsigned int size_in_bytes = type_size_in_bits(tp) / CHAR_SIZE; 3821 tnode_t *tn = build_integer_constant(SIZEOF_TSPEC, size_in_bytes); 3822 tn->tn_system_dependent = true; 3823 debug_step("build_sizeof '%s' = %u", type_name(tp), size_in_bytes); 3824 return tn; 3825 } 3826 3827 /* 3828 * Create a constant node for offsetof. 3829 */ 3830 /* ARGSUSED */ /* See implementation comments. */ 3831 tnode_t * 3832 build_offsetof(const type_t *tp, const sym_t *sym) 3833 { 3834 unsigned int offset_in_bytes; 3835 tnode_t *tn; 3836 3837 if (!is_struct_or_union(tp->t_tspec)) 3838 /* unacceptable operand of '%s' */ 3839 error(111, "offsetof"); 3840 3841 /* XXX: wrong size, no checking for sym fixme */ 3842 offset_in_bytes = type_size_in_bits(tp) / CHAR_SIZE; 3843 tn = build_integer_constant(SIZEOF_TSPEC, offset_in_bytes); 3844 tn->tn_system_dependent = true; 3845 return tn; 3846 } 3847 3848 unsigned int 3849 type_size_in_bits(const type_t *tp) 3850 { 3851 unsigned int elem, elsz; 3852 bool flex; 3853 3854 elem = 1; 3855 flex = false; 3856 lint_assert(tp != NULL); 3857 while (tp->t_tspec == ARRAY) { 3858 flex = true; /* allow c99 flex arrays [] [0] */ 3859 elem *= tp->t_dim; 3860 tp = tp->t_subt; 3861 } 3862 if (elem == 0) { 3863 if (!flex) { 3864 /* cannot take size/alignment of incomplete type */ 3865 error(143); 3866 elem = 1; 3867 } 3868 } 3869 switch (tp->t_tspec) { 3870 case FUNC: 3871 /* cannot take size/alignment of function type '%s' */ 3872 error(144, type_name(tp)); 3873 elsz = 1; 3874 break; 3875 case STRUCT: 3876 case UNION: 3877 if (is_incomplete(tp)) { 3878 /* cannot take size/alignment of incomplete type */ 3879 error(143); 3880 elsz = 1; 3881 } else { 3882 elsz = tp->t_str->sou_size_in_bits; 3883 } 3884 break; 3885 case ENUM: 3886 if (is_incomplete(tp)) { 3887 /* cannot take size/alignment of incomplete type */ 3888 warning(143); 3889 } 3890 /* FALLTHROUGH */ 3891 default: 3892 if (tp->t_bitfield) { 3893 /* cannot take size/alignment of bit-field */ 3894 error(145); 3895 } 3896 if (tp->t_tspec == VOID) { 3897 /* cannot take size/alignment of void */ 3898 error(146); 3899 elsz = 1; 3900 } else { 3901 elsz = size_in_bits(tp->t_tspec); 3902 lint_assert(elsz > 0); 3903 } 3904 break; 3905 } 3906 3907 return elem * elsz; 3908 } 3909 3910 tnode_t * 3911 build_alignof(const type_t *tp) 3912 { 3913 switch (tp->t_tspec) { 3914 case ARRAY: 3915 break; 3916 3917 case FUNC: 3918 /* cannot take size/alignment of function type '%s' */ 3919 error(144, type_name(tp)); 3920 return 0; 3921 3922 case STRUCT: 3923 case UNION: 3924 if (is_incomplete(tp)) { 3925 /* cannot take size/alignment of incomplete type */ 3926 error(143); 3927 return 0; 3928 } 3929 break; 3930 case ENUM: 3931 break; 3932 default: 3933 if (tp->t_bitfield) { 3934 /* cannot take size/alignment of bit-field */ 3935 error(145); 3936 return 0; 3937 } 3938 if (tp->t_tspec == VOID) { 3939 /* cannot take size/alignment of void */ 3940 error(146); 3941 return 0; 3942 } 3943 break; 3944 } 3945 3946 return build_integer_constant(SIZEOF_TSPEC, 3947 (int64_t)alignment_in_bits(tp) / CHAR_SIZE); 3948 } 3949 3950 /* 3951 * Type casts. 3952 */ 3953 tnode_t * 3954 cast(tnode_t *tn, type_t *tp) 3955 { 3956 tspec_t nt, ot; 3957 3958 if (tn == NULL) 3959 return NULL; 3960 3961 tn = cconv(tn); 3962 3963 lint_assert(tp != NULL); 3964 nt = tp->t_tspec; 3965 ot = tn->tn_type->t_tspec; 3966 3967 if (nt == VOID) { 3968 /* 3969 * C90 6.3.4, C99 6.5.4p2 and C11 6.5.4p2 allow any type to 3970 * be cast to void. The only other allowed casts are from a 3971 * scalar type to a scalar type. 3972 */ 3973 } else if (nt == UNION) { 3974 sym_t *m; 3975 struct_or_union *str = tp->t_str; 3976 if (!allow_gcc) { 3977 /* union cast is a GCC extension */ 3978 error(328); 3979 return NULL; 3980 } 3981 for (m = str->sou_first_member; m != NULL; m = m->s_next) { 3982 if (types_compatible(m->s_type, tn->tn_type, 3983 false, false, NULL)) { 3984 tn = expr_alloc_tnode(); 3985 tn->tn_op = CVT; 3986 tn->tn_type = tp; 3987 tn->tn_cast = true; 3988 tn->tn_right = NULL; 3989 return tn; 3990 } 3991 } 3992 /* type '%s' is not a member of '%s' */ 3993 error(329, type_name(tn->tn_type), type_name(tp)); 3994 return NULL; 3995 } else if (nt == STRUCT || nt == ARRAY || nt == FUNC) { 3996 /* Casting to a struct is an undocumented GCC extension. */ 3997 if (!(allow_gcc && nt == STRUCT)) 3998 goto invalid_cast; 3999 } else if (is_struct_or_union(ot)) { 4000 goto invalid_cast; 4001 } else if (ot == VOID) { 4002 /* improper cast of void expression */ 4003 error(148); 4004 return NULL; 4005 } else if (is_integer(nt) && is_scalar(ot)) { 4006 /* ok */ 4007 } else if (is_floating(nt) && is_arithmetic(ot)) { 4008 /* ok */ 4009 } else if (nt == PTR && is_integer(ot)) { 4010 /* ok */ 4011 } else if (nt == PTR && ot == PTR) { 4012 if (!tp->t_subt->t_const && tn->tn_type->t_subt->t_const) { 4013 if (hflag) 4014 /* cast discards 'const' from type '%s' */ 4015 warning(275, type_name(tn->tn_type)); 4016 } 4017 } else 4018 goto invalid_cast; 4019 4020 if (any_query_enabled && types_compatible(tp, tn->tn_type, 4021 false, false, NULL)) { 4022 /* no-op cast from '%s' to '%s' */ 4023 query_message(6, type_name(tn->tn_type), type_name(tp)); 4024 } 4025 4026 tn = convert(CVT, 0, tp, tn); 4027 tn->tn_cast = true; 4028 4029 return tn; 4030 4031 invalid_cast: 4032 /* invalid cast from '%s' to '%s' */ 4033 error(147, type_name(tn->tn_type), type_name(tp)); 4034 return NULL; 4035 } 4036 4037 /* 4038 * Create the node for a function argument. 4039 * All necessary conversions and type checks are done in 4040 * build_function_call because build_function_argument has no 4041 * information about expected argument types. 4042 */ 4043 tnode_t * 4044 build_function_argument(tnode_t *args, tnode_t *arg) 4045 { 4046 /* 4047 * If there was a serious error in the expression for the argument, 4048 * create a dummy argument so the positions of the remaining arguments 4049 * will not change. 4050 */ 4051 if (arg == NULL) 4052 arg = build_integer_constant(INT, 0); 4053 4054 return new_tnode(PUSH, arg->tn_sys, arg->tn_type, arg, args); 4055 } 4056 4057 /* 4058 * Create the node for a function call. Also check types of 4059 * function arguments and insert conversions, if necessary. 4060 */ 4061 tnode_t * 4062 build_function_call(tnode_t *func, bool sys, tnode_t *args) 4063 { 4064 tnode_t *ntn; 4065 op_t fcop; 4066 4067 if (func == NULL) 4068 return NULL; 4069 4070 if (func->tn_op == NAME && func->tn_type->t_tspec == FUNC) { 4071 fcop = CALL; 4072 } else { 4073 fcop = ICALL; 4074 } 4075 4076 check_ctype_function_call(func, args); 4077 4078 /* 4079 * after cconv() func will always be a pointer to a function 4080 * if it is a valid function designator. 4081 */ 4082 func = cconv(func); 4083 4084 if (func->tn_type->t_tspec != PTR || 4085 func->tn_type->t_subt->t_tspec != FUNC) { 4086 /* cannot call '%s', must be a function */ 4087 error(149, type_name(func->tn_type)); 4088 return NULL; 4089 } 4090 4091 args = check_function_arguments(func->tn_type->t_subt, args); 4092 4093 ntn = new_tnode(fcop, sys, func->tn_type->t_subt->t_subt, func, args); 4094 4095 return ntn; 4096 } 4097 4098 /* 4099 * Check types of all function arguments and insert conversions, 4100 * if necessary. 4101 */ 4102 static tnode_t * 4103 check_function_arguments(type_t *ftp, tnode_t *args) 4104 { 4105 tnode_t *arg; 4106 sym_t *asym; 4107 tspec_t at; 4108 int narg, npar, n, i; 4109 4110 /* get # of args in the prototype */ 4111 npar = 0; 4112 for (asym = ftp->t_args; asym != NULL; asym = asym->s_next) 4113 npar++; 4114 4115 /* get # of args in function call */ 4116 narg = 0; 4117 for (arg = args; arg != NULL; arg = arg->tn_right) 4118 narg++; 4119 4120 asym = ftp->t_args; 4121 if (ftp->t_proto && npar != narg && !(ftp->t_vararg && npar < narg)) { 4122 /* argument mismatch: %d %s passed, %d expected */ 4123 error(150, narg, narg > 1 ? "arguments" : "argument", npar); 4124 asym = NULL; 4125 } 4126 4127 for (n = 1; n <= narg; n++) { 4128 4129 /* 4130 * The rightmost argument is at the top of the argument 4131 * subtree. 4132 */ 4133 for (i = narg, arg = args; i > n; i--, arg = arg->tn_right) 4134 continue; 4135 4136 /* some things which are always not allowed */ 4137 if ((at = arg->tn_left->tn_type->t_tspec) == VOID) { 4138 /* void expressions may not be arguments, arg #%d */ 4139 error(151, n); 4140 return NULL; 4141 } else if (is_struct_or_union(at) && 4142 is_incomplete(arg->tn_left->tn_type)) { 4143 /* argument cannot have unknown size, arg #%d */ 4144 error(152, n); 4145 return NULL; 4146 } else if (is_integer(at) && 4147 arg->tn_left->tn_type->t_is_enum && 4148 is_incomplete(arg->tn_left->tn_type)) { 4149 /* argument cannot have unknown size, arg #%d */ 4150 warning(152, n); 4151 } 4152 4153 /* class conversions (arg in value context) */ 4154 arg->tn_left = cconv(arg->tn_left); 4155 4156 if (asym != NULL) { 4157 arg->tn_left = check_prototype_argument( 4158 n, asym->s_type, arg->tn_left); 4159 } else { 4160 arg->tn_left = promote(NOOP, true, arg->tn_left); 4161 } 4162 arg->tn_type = arg->tn_left->tn_type; 4163 4164 if (asym != NULL) 4165 asym = asym->s_next; 4166 } 4167 4168 return args; 4169 } 4170 4171 /* 4172 * Compare the type of an argument with the corresponding type of a 4173 * prototype parameter. If it is a valid combination, but both types 4174 * are not the same, insert a conversion to convert the argument into 4175 * the type of the parameter. 4176 */ 4177 static tnode_t * 4178 check_prototype_argument( 4179 int n, /* pos of arg */ 4180 type_t *tp, /* expected type (from prototype) */ 4181 tnode_t *tn) /* argument */ 4182 { 4183 tnode_t *ln; 4184 bool dowarn; 4185 4186 ln = xcalloc(1, sizeof(*ln)); 4187 ln->tn_type = expr_unqualified_type(tp); 4188 ln->tn_lvalue = true; 4189 if (typeok(FARG, n, ln, tn)) { 4190 if (!types_compatible(tp, tn->tn_type, 4191 true, false, (dowarn = false, &dowarn)) || dowarn) 4192 tn = convert(FARG, n, tp, tn); 4193 } 4194 free(ln); 4195 return tn; 4196 } 4197 4198 /* 4199 * Return the value of an integral constant expression. 4200 * If the expression is not constant or its type is not an integer 4201 * type, an error message is printed. 4202 */ 4203 val_t * 4204 constant(tnode_t *tn, bool required) 4205 { 4206 val_t *v; 4207 4208 if (tn != NULL) 4209 tn = cconv(tn); 4210 if (tn != NULL) 4211 tn = promote(NOOP, false, tn); 4212 4213 v = xcalloc(1, sizeof(*v)); 4214 4215 if (tn == NULL) { 4216 lint_assert(nerr != 0); 4217 debug_step("constant node is null; returning 1 instead"); 4218 v->v_tspec = INT; 4219 v->v_quad = 1; 4220 return v; 4221 } 4222 4223 v->v_tspec = tn->tn_type->t_tspec; 4224 4225 if (tn->tn_op == CON) { 4226 lint_assert(tn->tn_type->t_tspec == tn->tn_val->v_tspec); 4227 if (is_integer(tn->tn_val->v_tspec)) { 4228 v->v_unsigned_since_c90 = 4229 tn->tn_val->v_unsigned_since_c90; 4230 v->v_quad = tn->tn_val->v_quad; 4231 return v; 4232 } 4233 v->v_quad = tn->tn_val->v_ldbl; 4234 } else { 4235 v->v_quad = 1; 4236 } 4237 4238 if (required) 4239 /* integral constant expression expected */ 4240 error(55); 4241 else 4242 /* variable array dimension is a C99/GCC extension */ 4243 c99ism(318); 4244 4245 if (!is_integer(v->v_tspec)) 4246 v->v_tspec = INT; 4247 4248 return v; 4249 } 4250 4251 static bool 4252 is_constcond_false(const tnode_t *tn, tspec_t t) 4253 { 4254 return (t == BOOL || t == INT) && 4255 tn->tn_op == CON && tn->tn_val->v_quad == 0; 4256 } 4257 4258 /* 4259 * Perform some tests on expressions which can't be done in build_binary() 4260 * and functions called by build_binary(). These tests must be done here 4261 * because we need some information about the context in which the operations 4262 * are performed. 4263 * After all tests are performed and dofreeblk is true, expr() frees the 4264 * memory which is used for the expression. 4265 */ 4266 void 4267 expr(tnode_t *tn, bool vctx, bool cond, bool dofreeblk, bool is_do_while) 4268 { 4269 4270 if (tn == NULL) { /* in case of errors */ 4271 expr_free_all(); 4272 return; 4273 } 4274 4275 /* expr() is also called in global initializations */ 4276 if (dcs->d_kind != DK_EXTERN && !is_do_while) 4277 check_statement_reachable(); 4278 4279 check_expr_misc(tn, vctx, cond, !cond, false, false, false); 4280 if (tn->tn_op == ASSIGN) { 4281 if (hflag && cond) 4282 /* assignment in conditional context */ 4283 warning(159); 4284 } else if (tn->tn_op == CON) { 4285 if (hflag && cond && !constcond_flag && 4286 !tn->tn_system_dependent && 4287 !(is_do_while && 4288 is_constcond_false(tn, tn->tn_type->t_tspec))) 4289 /* constant in conditional context */ 4290 warning(161); 4291 } 4292 if (!modtab[tn->tn_op].m_has_side_effect) { 4293 /* 4294 * for left operands of COMMA this warning is already 4295 * printed 4296 */ 4297 if (tn->tn_op != COMMA && !vctx && !cond) 4298 check_null_effect(tn); 4299 } 4300 debug_node(tn); 4301 4302 /* free the tree memory */ 4303 if (dofreeblk) 4304 expr_free_all(); 4305 } 4306 4307 static bool 4308 has_side_effect(const tnode_t *tn) /* NOLINT(misc-no-recursion) */ 4309 { 4310 op_t op = tn->tn_op; 4311 4312 if (modtab[op].m_has_side_effect) 4313 return true; 4314 4315 if (op == CVT && tn->tn_type->t_tspec == VOID) 4316 return has_side_effect(tn->tn_left); 4317 4318 /* XXX: Why not has_side_effect(tn->tn_left) as well? */ 4319 if (op == LOGAND || op == LOGOR) 4320 return has_side_effect(tn->tn_right); 4321 4322 /* XXX: Why not has_side_effect(tn->tn_left) as well? */ 4323 if (op == QUEST) 4324 return has_side_effect(tn->tn_right); 4325 4326 if (op == COLON || op == COMMA) { 4327 return has_side_effect(tn->tn_left) || 4328 has_side_effect(tn->tn_right); 4329 } 4330 4331 return false; 4332 } 4333 4334 static bool 4335 is_void_cast(const tnode_t *tn) 4336 { 4337 4338 return tn->tn_op == CVT && tn->tn_cast && 4339 tn->tn_type->t_tspec == VOID; 4340 } 4341 4342 static bool 4343 is_local_symbol(const tnode_t *tn) 4344 { 4345 4346 return tn->tn_op == LOAD && 4347 tn->tn_left->tn_op == NAME && 4348 tn->tn_left->tn_sym->s_scl == AUTO; 4349 } 4350 4351 static bool 4352 is_int_constant_zero(const tnode_t *tn) 4353 { 4354 4355 return tn->tn_op == CON && 4356 tn->tn_type->t_tspec == INT && 4357 tn->tn_val->v_quad == 0; 4358 } 4359 4360 static void 4361 check_null_effect(const tnode_t *tn) 4362 { 4363 4364 if (!hflag) 4365 return; 4366 if (has_side_effect(tn)) 4367 return; 4368 if (is_void_cast(tn) && is_local_symbol(tn->tn_left)) 4369 return; 4370 if (is_void_cast(tn) && is_int_constant_zero(tn->tn_left)) 4371 return; 4372 4373 /* expression has null effect */ 4374 warning(129); 4375 } 4376 4377 static void 4378 check_expr_addr(const tnode_t *ln, bool szof, bool fcall) 4379 { 4380 /* XXX: Taking warn_about_unreachable into account here feels wrong. */ 4381 if (ln->tn_op == NAME && (reached || !warn_about_unreachable)) { 4382 if (!szof) 4383 mark_as_set(ln->tn_sym); 4384 mark_as_used(ln->tn_sym, fcall, szof); 4385 } 4386 if (ln->tn_op == INDIR && ln->tn_left->tn_op == PLUS) 4387 /* check the range of array indices */ 4388 check_array_index(ln->tn_left, true); 4389 } 4390 4391 static void 4392 check_expr_load(const tnode_t *ln) 4393 { 4394 if (ln->tn_op == INDIR && ln->tn_left->tn_op == PLUS) 4395 /* check the range of array indices */ 4396 check_array_index(ln->tn_left, false); 4397 } 4398 4399 static void 4400 check_expr_side_effect(const tnode_t *ln, bool szof) 4401 { 4402 scl_t sc; 4403 dinfo_t *di; 4404 4405 /* XXX: Taking warn_about_unreachable into account here feels wrong. */ 4406 if (ln->tn_op == NAME && (reached || !warn_about_unreachable)) { 4407 sc = ln->tn_sym->s_scl; 4408 /* 4409 * Look if there was a asm statement in one of the 4410 * compound statements we are in. If not, we don't 4411 * print a warning. 4412 */ 4413 for (di = dcs; di != NULL; di = di->d_enclosing) { 4414 if (di->d_asm) 4415 break; 4416 } 4417 if (sc != EXTERN && sc != STATIC && 4418 !ln->tn_sym->s_set && !szof && di == NULL) { 4419 /* '%s' may be used before set */ 4420 warning(158, ln->tn_sym->s_name); 4421 mark_as_set(ln->tn_sym); 4422 } 4423 mark_as_used(ln->tn_sym, false, false); 4424 } 4425 } 4426 4427 static void 4428 check_expr_assign(const tnode_t *ln, bool szof) 4429 { 4430 /* XXX: Taking warn_about_unreachable into account here feels wrong. */ 4431 if (ln->tn_op == NAME && !szof && (reached || !warn_about_unreachable)) { 4432 mark_as_set(ln->tn_sym); 4433 if (ln->tn_sym->s_scl == EXTERN) 4434 outusg(ln->tn_sym); 4435 } 4436 if (ln->tn_op == INDIR && ln->tn_left->tn_op == PLUS) 4437 /* check the range of array indices */ 4438 check_array_index(ln->tn_left, false); 4439 } 4440 4441 static void 4442 check_expr_call(const tnode_t *tn, const tnode_t *ln, 4443 bool szof, bool vctx, bool cond, bool retval_discarded) 4444 { 4445 lint_assert(ln->tn_op == ADDR); 4446 lint_assert(ln->tn_left->tn_op == NAME); 4447 if (!szof && 4448 !is_compiler_builtin(ln->tn_left->tn_sym->s_name)) 4449 outcall(tn, vctx || cond, retval_discarded); 4450 } 4451 4452 static bool 4453 check_expr_op(const tnode_t *tn, op_t op, const tnode_t *ln, 4454 bool szof, bool fcall, bool vctx, bool cond, 4455 bool retval_discarded, bool eqwarn) 4456 { 4457 switch (op) { 4458 case ADDR: 4459 check_expr_addr(ln, szof, fcall); 4460 break; 4461 case LOAD: 4462 check_expr_load(ln); 4463 /* FALLTHROUGH */ 4464 case PUSH: 4465 case INCBEF: 4466 case DECBEF: 4467 case INCAFT: 4468 case DECAFT: 4469 case ADDASS: 4470 case SUBASS: 4471 case MULASS: 4472 case DIVASS: 4473 case MODASS: 4474 case ANDASS: 4475 case ORASS: 4476 case XORASS: 4477 case SHLASS: 4478 case SHRASS: 4479 case REAL: 4480 case IMAG: 4481 check_expr_side_effect(ln, szof); 4482 break; 4483 case ASSIGN: 4484 check_expr_assign(ln, szof); 4485 break; 4486 case CALL: 4487 check_expr_call(tn, ln, szof, vctx, cond, retval_discarded); 4488 break; 4489 case EQ: 4490 if (hflag && eqwarn) 4491 /* operator '==' found where '=' was expected */ 4492 warning(160); 4493 break; 4494 case CON: 4495 case NAME: 4496 case STRING: 4497 return false; 4498 default: 4499 break; 4500 } 4501 return true; 4502 } 4503 4504 /* 4505 * vctx ??? 4506 * cond whether the expression is a condition that 4507 * will be compared with 0 4508 * eqwarn whether the operator '==' might be a 4509 * misspelled '=' 4510 * fcall whether the expression is a function call 4511 * retval_discarded whether the return value of a function call 4512 * is discarded; such calls will be analyzed by 4513 * lint2 in messages 4, 8 and 9 4514 * szof whether the expression is part of a sizeof 4515 * expression, which means that its value is 4516 * discarded since only the type is relevant 4517 */ 4518 void 4519 check_expr_misc(const tnode_t *tn, bool vctx, bool cond, 4520 bool eqwarn, bool fcall, bool retval_discarded, bool szof) 4521 { 4522 tnode_t *ln, *rn; 4523 const mod_t *mp; 4524 op_t op; 4525 bool cvctx, ccond, eq, discard; 4526 4527 if (tn == NULL) 4528 return; 4529 4530 ln = tn->tn_left; 4531 rn = tn->tn_right; 4532 mp = &modtab[op = tn->tn_op]; 4533 4534 if (!check_expr_op(tn, op, ln, 4535 szof, fcall, vctx, cond, retval_discarded, eqwarn)) 4536 return; 4537 4538 cvctx = mp->m_value_context; 4539 ccond = mp->m_compares_with_zero; 4540 eq = mp->m_warn_if_operand_eq && 4541 !ln->tn_parenthesized && 4542 rn != NULL && !rn->tn_parenthesized; 4543 4544 /* 4545 * values of operands of ':' are not used if the type of at least 4546 * one of the operands (for gcc compatibility) is void 4547 * XXX test/value context of QUEST should probably be used as 4548 * context for both operands of COLON 4549 */ 4550 if (op == COLON && tn->tn_type->t_tspec == VOID) 4551 cvctx = ccond = false; 4552 discard = op == CVT && tn->tn_type->t_tspec == VOID; 4553 check_expr_misc(ln, cvctx, ccond, eq, op == CALL, discard, szof); 4554 4555 switch (op) { 4556 case PUSH: 4557 if (rn != NULL) 4558 check_expr_misc(rn, false, false, eq, false, false, 4559 szof); 4560 break; 4561 case LOGAND: 4562 case LOGOR: 4563 check_expr_misc(rn, false, true, eq, false, false, szof); 4564 break; 4565 case COLON: 4566 check_expr_misc(rn, cvctx, ccond, eq, false, false, szof); 4567 break; 4568 case COMMA: 4569 check_expr_misc(rn, vctx, cond, false, false, false, szof); 4570 break; 4571 default: 4572 if (mp->m_binary) 4573 check_expr_misc(rn, true, false, eq, false, false, 4574 szof); 4575 break; 4576 } 4577 } 4578 4579 /* 4580 * Checks the range of array indices, if possible. 4581 * amper is set if only the address of the element is used. This 4582 * means that the index is allowed to refer to the first element 4583 * after the array. 4584 */ 4585 static void 4586 check_array_index(tnode_t *tn, bool amper) 4587 { 4588 int dim; 4589 tnode_t *ln, *rn; 4590 int elsz; 4591 int64_t con; 4592 4593 ln = tn->tn_left; 4594 rn = tn->tn_right; 4595 4596 /* We can only check constant indices. */ 4597 if (rn->tn_op != CON) 4598 return; 4599 4600 /* Return if the left node does not stem from an array. */ 4601 if (ln->tn_op != ADDR) 4602 return; 4603 if (ln->tn_left->tn_op != STRING && ln->tn_left->tn_op != NAME) 4604 return; 4605 if (ln->tn_left->tn_type->t_tspec != ARRAY) 4606 return; 4607 4608 /* 4609 * For incomplete array types, we can print a warning only if 4610 * the index is negative. 4611 */ 4612 if (is_incomplete(ln->tn_left->tn_type) && rn->tn_val->v_quad >= 0) 4613 return; 4614 4615 /* Get the size of one array element */ 4616 if ((elsz = length_in_bits(ln->tn_type->t_subt, NULL)) == 0) 4617 return; 4618 elsz /= CHAR_SIZE; 4619 4620 /* Change the unit of the index from bytes to element size. */ 4621 if (is_uinteger(rn->tn_type->t_tspec)) { 4622 con = (uint64_t)rn->tn_val->v_quad / elsz; 4623 } else { 4624 con = rn->tn_val->v_quad / elsz; 4625 } 4626 4627 dim = ln->tn_left->tn_type->t_dim + (amper ? 1 : 0); 4628 4629 if (!is_uinteger(rn->tn_type->t_tspec) && con < 0) { 4630 /* array subscript cannot be negative: %ld */ 4631 warning(167, (long)con); 4632 } else if (dim > 0 && (uint64_t)con >= (uint64_t)dim) { 4633 /* array subscript cannot be > %d: %ld */ 4634 warning(168, dim - 1, (long)con); 4635 } 4636 } 4637 4638 static bool 4639 is_out_of_char_range(const tnode_t *tn) 4640 { 4641 return tn->tn_op == CON && 4642 !(0 <= tn->tn_val->v_quad && 4643 tn->tn_val->v_quad < 1 << (CHAR_SIZE - 1)); 4644 } 4645 4646 /* 4647 * Check for ordered comparisons of unsigned values with 0. 4648 */ 4649 static void 4650 check_integer_comparison(op_t op, tnode_t *ln, tnode_t *rn) 4651 { 4652 tspec_t lt, rt; 4653 4654 lt = ln->tn_type->t_tspec; 4655 rt = rn->tn_type->t_tspec; 4656 4657 if (ln->tn_op != CON && rn->tn_op != CON) 4658 return; 4659 4660 if (!is_integer(lt) || !is_integer(rt)) 4661 return; 4662 4663 if (hflag || pflag) { 4664 if (lt == CHAR && is_out_of_char_range(rn)) { 4665 /* nonportable character comparison '%s %d' */ 4666 warning(230, op_name(op), (int)rn->tn_val->v_quad); 4667 return; 4668 } 4669 if (rt == CHAR && is_out_of_char_range(ln)) { 4670 /* nonportable character comparison '%s %d' */ 4671 warning(230, op_name(op), (int)ln->tn_val->v_quad); 4672 return; 4673 } 4674 } 4675 4676 if (is_uinteger(lt) && !is_uinteger(rt) && 4677 rn->tn_op == CON && rn->tn_val->v_quad <= 0) { 4678 if (rn->tn_val->v_quad < 0) { 4679 /* operator '%s' compares '%s' with '%s' */ 4680 warning(162, op_name(op), 4681 type_name(ln->tn_type), "negative constant"); 4682 } else if (op == LT || op == GE) { 4683 /* operator '%s' compares '%s' with '%s' */ 4684 warning(162, op_name(op), type_name(ln->tn_type), "0"); 4685 } 4686 return; 4687 } 4688 if (is_uinteger(rt) && !is_uinteger(lt) && 4689 ln->tn_op == CON && ln->tn_val->v_quad <= 0) { 4690 if (ln->tn_val->v_quad < 0) { 4691 /* operator '%s' compares '%s' with '%s' */ 4692 warning(162, op_name(op), 4693 "negative constant", type_name(rn->tn_type)); 4694 } else if (op == GT || op == LE) { 4695 /* operator '%s' compares '%s' with '%s' */ 4696 warning(162, op_name(op), "0", type_name(rn->tn_type)); 4697 } 4698 return; 4699 } 4700 } 4701 4702 /* 4703 * Return whether the expression can be used for static initialization. 4704 * 4705 * Constant initialization expressions must be constant or an address 4706 * of a static object with an optional offset. In the first case, 4707 * the result is returned in *offsp. In the second case, the static 4708 * object is returned in *symp and the offset in *offsp. 4709 * 4710 * The expression can consist of PLUS, MINUS, ADDR, NAME, STRING and 4711 * CON. Type conversions are allowed if they do not change binary 4712 * representation (including width). 4713 * 4714 * C99 6.6 "Constant expressions" 4715 * C99 6.7.8p4 restricts initializers for static storage duration 4716 */ 4717 bool 4718 constant_addr(const tnode_t *tn, const sym_t **symp, ptrdiff_t *offsp) 4719 { 4720 const sym_t *sym; 4721 ptrdiff_t offs1, offs2; 4722 tspec_t t, ot; 4723 4724 switch (tn->tn_op) { 4725 case MINUS: 4726 if (tn->tn_right->tn_op == CVT) 4727 return constant_addr(tn->tn_right, symp, offsp); 4728 else if (tn->tn_right->tn_op != CON) 4729 return false; 4730 /* FALLTHROUGH */ 4731 case PLUS: 4732 offs1 = offs2 = 0; 4733 if (tn->tn_left->tn_op == CON) { 4734 offs1 = (ptrdiff_t)tn->tn_left->tn_val->v_quad; 4735 if (!constant_addr(tn->tn_right, &sym, &offs2)) 4736 return false; 4737 } else if (tn->tn_right->tn_op == CON) { 4738 offs2 = (ptrdiff_t)tn->tn_right->tn_val->v_quad; 4739 if (tn->tn_op == MINUS) 4740 offs2 = -offs2; 4741 if (!constant_addr(tn->tn_left, &sym, &offs1)) 4742 return false; 4743 } else { 4744 return false; 4745 } 4746 *symp = sym; 4747 *offsp = offs1 + offs2; 4748 return true; 4749 case ADDR: 4750 if (tn->tn_left->tn_op == NAME) { 4751 *symp = tn->tn_left->tn_sym; 4752 *offsp = 0; 4753 return true; 4754 } else { 4755 /* 4756 * If this would be the front end of a compiler we 4757 * would return a label instead of 0, at least if 4758 * 'tn->tn_left->tn_op == STRING'. 4759 */ 4760 *symp = NULL; 4761 *offsp = 0; 4762 return true; 4763 } 4764 case CVT: 4765 t = tn->tn_type->t_tspec; 4766 ot = tn->tn_left->tn_type->t_tspec; 4767 if ((!is_integer(t) && t != PTR) || 4768 (!is_integer(ot) && ot != PTR)) { 4769 return false; 4770 } 4771 #if 0 4772 /* 4773 * consider: 4774 * struct foo { 4775 * unsigned char a; 4776 * } f = { 4777 * (unsigned char)(unsigned long) 4778 * (&(((struct foo *)0)->a)) 4779 * }; 4780 * since psize(unsigned long) != psize(unsigned char), 4781 * this fails. 4782 */ 4783 else if (psize(t) != psize(ot)) 4784 return -1; 4785 #endif 4786 return constant_addr(tn->tn_left, symp, offsp); 4787 default: 4788 return false; 4789 } 4790 } 4791 4792 /* Append s2 to s1, then free s2. */ 4793 strg_t * 4794 cat_strings(strg_t *s1, strg_t *s2) 4795 { 4796 4797 if (s1->st_char != s2->st_char) { 4798 /* cannot concatenate wide and regular string literals */ 4799 error(292); 4800 return s1; 4801 } 4802 4803 size_t len1 = s1->st_len; 4804 size_t len2 = s2->st_len; 4805 size_t chsize = s1->st_char ? sizeof(char) : sizeof(wchar_t); 4806 size_t size1 = len1 * chsize; 4807 size_t size2 = (len2 + 1) * chsize; 4808 s1->st_mem = xrealloc(s1->st_mem, size1 + size2); 4809 memcpy((char *)s1->st_mem + size1, s2->st_mem, size2); 4810 free(s2->st_mem); 4811 4812 s1->st_len = len1 + len2; 4813 free(s2); 4814 4815 return s1; 4816 } 4817 4818 static bool 4819 is_confusing_precedence(op_t op, op_t lop, bool lparen, op_t rop, bool rparen) 4820 { 4821 4822 if (op == SHL || op == SHR) { 4823 if (!lparen && (lop == PLUS || lop == MINUS)) 4824 return true; 4825 if (!rparen && (rop == PLUS || rop == MINUS)) 4826 return true; 4827 return false; 4828 } 4829 4830 if (op == LOGOR) { 4831 if (!lparen && lop == LOGAND) 4832 return true; 4833 if (!rparen && rop == LOGAND) 4834 return true; 4835 return false; 4836 } 4837 4838 lint_assert(op == BITAND || op == BITXOR || op == BITOR); 4839 if (!lparen && lop != op) { 4840 if (lop == PLUS || lop == MINUS) 4841 return true; 4842 if (lop == BITAND || lop == BITXOR) 4843 return true; 4844 } 4845 if (!rparen && rop != op) { 4846 if (rop == PLUS || rop == MINUS) 4847 return true; 4848 if (rop == BITAND || rop == BITXOR) 4849 return true; 4850 } 4851 return false; 4852 } 4853 4854 /* 4855 * Print a warning if the given node has operands which should be 4856 * parenthesized. 4857 * 4858 * XXX Does not work if an operand is a constant expression. Constant 4859 * expressions are already folded. 4860 */ 4861 static void 4862 check_precedence_confusion(tnode_t *tn) 4863 { 4864 tnode_t *ln, *rn; 4865 4866 if (!hflag) 4867 return; 4868 4869 debug_node(tn); 4870 4871 lint_assert(is_binary(tn)); 4872 for (ln = tn->tn_left; ln->tn_op == CVT; ln = ln->tn_left) 4873 continue; 4874 for (rn = tn->tn_right; rn->tn_op == CVT; rn = rn->tn_left) 4875 continue; 4876 4877 if (is_confusing_precedence(tn->tn_op, 4878 ln->tn_op, ln->tn_parenthesized, 4879 rn->tn_op, rn->tn_parenthesized)) { 4880 /* precedence confusion possible: parenthesize! */ 4881 warning(169); 4882 } 4883 } 4884 4885 typedef struct stmt_expr { 4886 struct memory_block *se_mem; 4887 sym_t *se_sym; 4888 struct stmt_expr *se_enclosing; 4889 } stmt_expr; 4890 4891 static stmt_expr *stmt_exprs; 4892 4893 void 4894 begin_statement_expr(void) 4895 { 4896 stmt_expr *se = xmalloc(sizeof(*se)); 4897 se->se_mem = expr_save_memory(); 4898 se->se_sym = NULL; 4899 se->se_enclosing = stmt_exprs; 4900 stmt_exprs = se; 4901 } 4902 4903 void 4904 do_statement_expr(tnode_t *tn) 4905 { 4906 block_level--; 4907 mem_block_level--; 4908 stmt_exprs->se_sym = tn != NULL 4909 ? mktempsym(block_dup_type(tn->tn_type)) 4910 : NULL; /* after a syntax error */ 4911 mem_block_level++; 4912 block_level++; 4913 /* ({ }) is a GCC extension */ 4914 gnuism(320); 4915 } 4916 4917 tnode_t * 4918 end_statement_expr(void) 4919 { 4920 stmt_expr *se = stmt_exprs; 4921 if (se->se_sym == NULL) 4922 return NULL; /* after a syntax error */ 4923 tnode_t *tn = build_name(se->se_sym, false); 4924 (void)expr_save_memory(); /* leak */ 4925 expr_restore_memory(se->se_mem); 4926 stmt_exprs = se->se_enclosing; 4927 free(se); 4928 return tn; 4929 } 4930
Indexes created Wed Sep 24 05:09:52 GMT 2025