search.c revision 1.10
1/* Breadth-first and depth-first routines for 2 searching multiple-inheritance lattice for GNU C++. 3 Copyright (C) 1987-2019 Free Software Foundation, Inc. 4 Contributed by Michael Tiemann (tiemann@cygnus.com) 5 6This file is part of GCC. 7 8GCC is free software; you can redistribute it and/or modify 9it under the terms of the GNU General Public License as published by 10the Free Software Foundation; either version 3, or (at your option) 11any later version. 12 13GCC is distributed in the hope that it will be useful, 14but WITHOUT ANY WARRANTY; without even the implied warranty of 15MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 16GNU General Public License for more details. 17 18You should have received a copy of the GNU General Public License 19along with GCC; see the file COPYING3. If not see 20<http://www.gnu.org/licenses/>. */ 21 22/* High-level class interface. */ 23 24#include "config.h" 25#include "system.h" 26#include "coretypes.h" 27#include "cp-tree.h" 28#include "intl.h" 29#include "toplev.h" 30#include "spellcheck-tree.h" 31#include "stringpool.h" 32#include "attribs.h" 33 34static int is_subobject_of_p (tree, tree); 35static tree dfs_lookup_base (tree, void *); 36static tree dfs_dcast_hint_pre (tree, void *); 37static tree dfs_dcast_hint_post (tree, void *); 38static tree dfs_debug_mark (tree, void *); 39static int check_hidden_convs (tree, int, int, tree, tree, tree); 40static tree split_conversions (tree, tree, tree, tree); 41static int lookup_conversions_r (tree, int, int, tree, tree, tree *); 42static int look_for_overrides_r (tree, tree); 43static tree lookup_field_r (tree, void *); 44static tree dfs_accessible_post (tree, void *); 45static tree dfs_walk_once_accessible (tree, bool, 46 tree (*pre_fn) (tree, void *), 47 tree (*post_fn) (tree, void *), 48 void *data); 49static tree dfs_access_in_type (tree, void *); 50static access_kind access_in_type (tree, tree); 51static tree dfs_get_pure_virtuals (tree, void *); 52 53 54/* Data for lookup_base and its workers. */ 55 56struct lookup_base_data_s 57{ 58 tree t; /* type being searched. */ 59 tree base; /* The base type we're looking for. */ 60 tree binfo; /* Found binfo. */ 61 bool via_virtual; /* Found via a virtual path. */ 62 bool ambiguous; /* Found multiply ambiguous */ 63 bool repeated_base; /* Whether there are repeated bases in the 64 hierarchy. */ 65 bool want_any; /* Whether we want any matching binfo. */ 66}; 67 68/* Worker function for lookup_base. See if we've found the desired 69 base and update DATA_ (a pointer to LOOKUP_BASE_DATA_S). */ 70 71static tree 72dfs_lookup_base (tree binfo, void *data_) 73{ 74 struct lookup_base_data_s *data = (struct lookup_base_data_s *) data_; 75 76 if (SAME_BINFO_TYPE_P (BINFO_TYPE (binfo), data->base)) 77 { 78 if (!data->binfo) 79 { 80 data->binfo = binfo; 81 data->via_virtual 82 = binfo_via_virtual (data->binfo, data->t) != NULL_TREE; 83 84 if (!data->repeated_base) 85 /* If there are no repeated bases, we can stop now. */ 86 return binfo; 87 88 if (data->want_any && !data->via_virtual) 89 /* If this is a non-virtual base, then we can't do 90 better. */ 91 return binfo; 92 93 return dfs_skip_bases; 94 } 95 else 96 { 97 gcc_assert (binfo != data->binfo); 98 99 /* We've found more than one matching binfo. */ 100 if (!data->want_any) 101 { 102 /* This is immediately ambiguous. */ 103 data->binfo = NULL_TREE; 104 data->ambiguous = true; 105 return error_mark_node; 106 } 107 108 /* Prefer one via a non-virtual path. */ 109 if (!binfo_via_virtual (binfo, data->t)) 110 { 111 data->binfo = binfo; 112 data->via_virtual = false; 113 return binfo; 114 } 115 116 /* There must be repeated bases, otherwise we'd have stopped 117 on the first base we found. */ 118 return dfs_skip_bases; 119 } 120 } 121 122 return NULL_TREE; 123} 124 125/* Returns true if type BASE is accessible in T. (BASE is known to be 126 a (possibly non-proper) base class of T.) If CONSIDER_LOCAL_P is 127 true, consider any special access of the current scope, or access 128 bestowed by friendship. */ 129 130bool 131accessible_base_p (tree t, tree base, bool consider_local_p) 132{ 133 tree decl; 134 135 /* [class.access.base] 136 137 A base class is said to be accessible if an invented public 138 member of the base class is accessible. 139 140 If BASE is a non-proper base, this condition is trivially 141 true. */ 142 if (same_type_p (t, base)) 143 return true; 144 /* Rather than inventing a public member, we use the implicit 145 public typedef created in the scope of every class. */ 146 decl = TYPE_FIELDS (base); 147 while (!DECL_SELF_REFERENCE_P (decl)) 148 decl = DECL_CHAIN (decl); 149 while (ANON_AGGR_TYPE_P (t)) 150 t = TYPE_CONTEXT (t); 151 return accessible_p (t, decl, consider_local_p); 152} 153 154/* Lookup BASE in the hierarchy dominated by T. Do access checking as 155 ACCESS specifies. Return the binfo we discover. If KIND_PTR is 156 non-NULL, fill with information about what kind of base we 157 discovered. 158 159 If the base is inaccessible, or ambiguous, then error_mark_node is 160 returned. If the tf_error bit of COMPLAIN is not set, no error 161 is issued. */ 162 163tree 164lookup_base (tree t, tree base, base_access access, 165 base_kind *kind_ptr, tsubst_flags_t complain) 166{ 167 tree binfo; 168 tree t_binfo; 169 base_kind bk; 170 171 /* "Nothing" is definitely not derived from Base. */ 172 if (t == NULL_TREE) 173 { 174 if (kind_ptr) 175 *kind_ptr = bk_not_base; 176 return NULL_TREE; 177 } 178 179 if (t == error_mark_node || base == error_mark_node) 180 { 181 if (kind_ptr) 182 *kind_ptr = bk_not_base; 183 return error_mark_node; 184 } 185 gcc_assert (TYPE_P (base)); 186 187 if (!TYPE_P (t)) 188 { 189 t_binfo = t; 190 t = BINFO_TYPE (t); 191 } 192 else 193 { 194 t = complete_type (TYPE_MAIN_VARIANT (t)); 195 if (dependent_type_p (t)) 196 if (tree open = currently_open_class (t)) 197 t = open; 198 t_binfo = TYPE_BINFO (t); 199 } 200 201 base = TYPE_MAIN_VARIANT (base); 202 203 /* If BASE is incomplete, it can't be a base of T--and instantiating it 204 might cause an error. */ 205 if (t_binfo && CLASS_TYPE_P (base) && COMPLETE_OR_OPEN_TYPE_P (base)) 206 { 207 struct lookup_base_data_s data; 208 209 data.t = t; 210 data.base = base; 211 data.binfo = NULL_TREE; 212 data.ambiguous = data.via_virtual = false; 213 data.repeated_base = CLASSTYPE_REPEATED_BASE_P (t); 214 data.want_any = access == ba_any; 215 216 dfs_walk_once (t_binfo, dfs_lookup_base, NULL, &data); 217 binfo = data.binfo; 218 219 if (!binfo) 220 bk = data.ambiguous ? bk_ambig : bk_not_base; 221 else if (binfo == t_binfo) 222 bk = bk_same_type; 223 else if (data.via_virtual) 224 bk = bk_via_virtual; 225 else 226 bk = bk_proper_base; 227 } 228 else 229 { 230 binfo = NULL_TREE; 231 bk = bk_not_base; 232 } 233 234 /* Check that the base is unambiguous and accessible. */ 235 if (access != ba_any) 236 switch (bk) 237 { 238 case bk_not_base: 239 break; 240 241 case bk_ambig: 242 if (complain & tf_error) 243 error ("%qT is an ambiguous base of %qT", base, t); 244 binfo = error_mark_node; 245 break; 246 247 default: 248 if ((access & ba_check_bit) 249 /* If BASE is incomplete, then BASE and TYPE are probably 250 the same, in which case BASE is accessible. If they 251 are not the same, then TYPE is invalid. In that case, 252 there's no need to issue another error here, and 253 there's no implicit typedef to use in the code that 254 follows, so we skip the check. */ 255 && COMPLETE_TYPE_P (base) 256 && !accessible_base_p (t, base, !(access & ba_ignore_scope))) 257 { 258 if (complain & tf_error) 259 error ("%qT is an inaccessible base of %qT", base, t); 260 binfo = error_mark_node; 261 bk = bk_inaccessible; 262 } 263 break; 264 } 265 266 if (kind_ptr) 267 *kind_ptr = bk; 268 269 return binfo; 270} 271 272/* Data for dcast_base_hint walker. */ 273 274struct dcast_data_s 275{ 276 tree subtype; /* The base type we're looking for. */ 277 int virt_depth; /* Number of virtual bases encountered from most 278 derived. */ 279 tree offset; /* Best hint offset discovered so far. */ 280 bool repeated_base; /* Whether there are repeated bases in the 281 hierarchy. */ 282}; 283 284/* Worker for dcast_base_hint. Search for the base type being cast 285 from. */ 286 287static tree 288dfs_dcast_hint_pre (tree binfo, void *data_) 289{ 290 struct dcast_data_s *data = (struct dcast_data_s *) data_; 291 292 if (BINFO_VIRTUAL_P (binfo)) 293 data->virt_depth++; 294 295 if (SAME_BINFO_TYPE_P (BINFO_TYPE (binfo), data->subtype)) 296 { 297 if (data->virt_depth) 298 { 299 data->offset = ssize_int (-1); 300 return data->offset; 301 } 302 if (data->offset) 303 data->offset = ssize_int (-3); 304 else 305 data->offset = BINFO_OFFSET (binfo); 306 307 return data->repeated_base ? dfs_skip_bases : data->offset; 308 } 309 310 return NULL_TREE; 311} 312 313/* Worker for dcast_base_hint. Track the virtual depth. */ 314 315static tree 316dfs_dcast_hint_post (tree binfo, void *data_) 317{ 318 struct dcast_data_s *data = (struct dcast_data_s *) data_; 319 320 if (BINFO_VIRTUAL_P (binfo)) 321 data->virt_depth--; 322 323 return NULL_TREE; 324} 325 326/* The dynamic cast runtime needs a hint about how the static SUBTYPE type 327 started from is related to the required TARGET type, in order to optimize 328 the inheritance graph search. This information is independent of the 329 current context, and ignores private paths, hence get_base_distance is 330 inappropriate. Return a TREE specifying the base offset, BOFF. 331 BOFF >= 0, there is only one public non-virtual SUBTYPE base at offset BOFF, 332 and there are no public virtual SUBTYPE bases. 333 BOFF == -1, SUBTYPE occurs as multiple public virtual or non-virtual bases. 334 BOFF == -2, SUBTYPE is not a public base. 335 BOFF == -3, SUBTYPE occurs as multiple public non-virtual bases. */ 336 337tree 338dcast_base_hint (tree subtype, tree target) 339{ 340 struct dcast_data_s data; 341 342 data.subtype = subtype; 343 data.virt_depth = 0; 344 data.offset = NULL_TREE; 345 data.repeated_base = CLASSTYPE_REPEATED_BASE_P (target); 346 347 dfs_walk_once_accessible (TYPE_BINFO (target), /*friends=*/false, 348 dfs_dcast_hint_pre, dfs_dcast_hint_post, &data); 349 return data.offset ? data.offset : ssize_int (-2); 350} 351 352/* Search for a member with name NAME in a multiple inheritance 353 lattice specified by TYPE. If it does not exist, return NULL_TREE. 354 If the member is ambiguously referenced, return `error_mark_node'. 355 Otherwise, return a DECL with the indicated name. If WANT_TYPE is 356 true, type declarations are preferred. */ 357 358/* Return the FUNCTION_DECL, RECORD_TYPE, UNION_TYPE, or 359 NAMESPACE_DECL corresponding to the innermost non-block scope. */ 360 361tree 362current_scope (void) 363{ 364 /* There are a number of cases we need to be aware of here: 365 current_class_type current_function_decl 366 global NULL NULL 367 fn-local NULL SET 368 class-local SET NULL 369 class->fn SET SET 370 fn->class SET SET 371 372 Those last two make life interesting. If we're in a function which is 373 itself inside a class, we need decls to go into the fn's decls (our 374 second case below). But if we're in a class and the class itself is 375 inside a function, we need decls to go into the decls for the class. To 376 achieve this last goal, we must see if, when both current_class_ptr and 377 current_function_decl are set, the class was declared inside that 378 function. If so, we know to put the decls into the class's scope. */ 379 if (current_function_decl && current_class_type 380 && ((DECL_FUNCTION_MEMBER_P (current_function_decl) 381 && same_type_p (DECL_CONTEXT (current_function_decl), 382 current_class_type)) 383 || (DECL_FRIEND_CONTEXT (current_function_decl) 384 && same_type_p (DECL_FRIEND_CONTEXT (current_function_decl), 385 current_class_type)))) 386 return current_function_decl; 387 388 if (current_class_type) 389 return current_class_type; 390 391 if (current_function_decl) 392 return current_function_decl; 393 394 return current_namespace; 395} 396 397/* Returns nonzero if we are currently in a function scope. Note 398 that this function returns zero if we are within a local class, but 399 not within a member function body of the local class. */ 400 401int 402at_function_scope_p (void) 403{ 404 tree cs = current_scope (); 405 /* Also check cfun to make sure that we're really compiling 406 this function (as opposed to having set current_function_decl 407 for access checking or some such). */ 408 return (cs && TREE_CODE (cs) == FUNCTION_DECL 409 && cfun && cfun->decl == current_function_decl); 410} 411 412/* Returns true if the innermost active scope is a class scope. */ 413 414bool 415at_class_scope_p (void) 416{ 417 tree cs = current_scope (); 418 return cs && TYPE_P (cs); 419} 420 421/* Returns true if the innermost active scope is a namespace scope. */ 422 423bool 424at_namespace_scope_p (void) 425{ 426 tree cs = current_scope (); 427 return cs && TREE_CODE (cs) == NAMESPACE_DECL; 428} 429 430/* Return the scope of DECL, as appropriate when doing name-lookup. */ 431 432tree 433context_for_name_lookup (tree decl) 434{ 435 /* [class.union] 436 437 For the purposes of name lookup, after the anonymous union 438 definition, the members of the anonymous union are considered to 439 have been defined in the scope in which the anonymous union is 440 declared. */ 441 tree context = DECL_CONTEXT (decl); 442 443 while (context && TYPE_P (context) 444 && (ANON_AGGR_TYPE_P (context) || UNSCOPED_ENUM_P (context))) 445 context = TYPE_CONTEXT (context); 446 if (!context) 447 context = global_namespace; 448 449 return context; 450} 451 452/* Returns true iff DECL is declared in TYPE. */ 453 454static bool 455member_declared_in_type (tree decl, tree type) 456{ 457 /* A normal declaration obviously counts. */ 458 if (context_for_name_lookup (decl) == type) 459 return true; 460 /* So does a using or access declaration. */ 461 if (DECL_LANG_SPECIFIC (decl) && !DECL_DISCRIMINATOR_P (decl) 462 && purpose_member (type, DECL_ACCESS (decl))) 463 return true; 464 return false; 465} 466 467/* The accessibility routines use BINFO_ACCESS for scratch space 468 during the computation of the accessibility of some declaration. */ 469 470/* Avoid walking up past a declaration of the member. */ 471 472static tree 473dfs_access_in_type_pre (tree binfo, void *data) 474{ 475 tree decl = (tree) data; 476 tree type = BINFO_TYPE (binfo); 477 if (member_declared_in_type (decl, type)) 478 return dfs_skip_bases; 479 return NULL_TREE; 480} 481 482#define BINFO_ACCESS(NODE) \ 483 ((access_kind) ((TREE_PUBLIC (NODE) << 1) | TREE_PRIVATE (NODE))) 484 485/* Set the access associated with NODE to ACCESS. */ 486 487#define SET_BINFO_ACCESS(NODE, ACCESS) \ 488 ((TREE_PUBLIC (NODE) = ((ACCESS) & 2) != 0), \ 489 (TREE_PRIVATE (NODE) = ((ACCESS) & 1) != 0)) 490 491/* Called from access_in_type via dfs_walk. Calculate the access to 492 DATA (which is really a DECL) in BINFO. */ 493 494static tree 495dfs_access_in_type (tree binfo, void *data) 496{ 497 tree decl = (tree) data; 498 tree type = BINFO_TYPE (binfo); 499 access_kind access = ak_none; 500 501 if (context_for_name_lookup (decl) == type) 502 { 503 /* If we have descended to the scope of DECL, just note the 504 appropriate access. */ 505 if (TREE_PRIVATE (decl)) 506 access = ak_private; 507 else if (TREE_PROTECTED (decl)) 508 access = ak_protected; 509 else 510 access = ak_public; 511 } 512 else 513 { 514 /* First, check for an access-declaration that gives us more 515 access to the DECL. */ 516 if (DECL_LANG_SPECIFIC (decl) && !DECL_DISCRIMINATOR_P (decl)) 517 { 518 tree decl_access = purpose_member (type, DECL_ACCESS (decl)); 519 520 if (decl_access) 521 { 522 decl_access = TREE_VALUE (decl_access); 523 524 if (decl_access == access_public_node) 525 access = ak_public; 526 else if (decl_access == access_protected_node) 527 access = ak_protected; 528 else if (decl_access == access_private_node) 529 access = ak_private; 530 else 531 gcc_unreachable (); 532 } 533 } 534 535 if (!access) 536 { 537 int i; 538 tree base_binfo; 539 vec<tree, va_gc> *accesses; 540 541 /* Otherwise, scan our baseclasses, and pick the most favorable 542 access. */ 543 accesses = BINFO_BASE_ACCESSES (binfo); 544 for (i = 0; BINFO_BASE_ITERATE (binfo, i, base_binfo); i++) 545 { 546 tree base_access = (*accesses)[i]; 547 access_kind base_access_now = BINFO_ACCESS (base_binfo); 548 549 if (base_access_now == ak_none || base_access_now == ak_private) 550 /* If it was not accessible in the base, or only 551 accessible as a private member, we can't access it 552 all. */ 553 base_access_now = ak_none; 554 else if (base_access == access_protected_node) 555 /* Public and protected members in the base become 556 protected here. */ 557 base_access_now = ak_protected; 558 else if (base_access == access_private_node) 559 /* Public and protected members in the base become 560 private here. */ 561 base_access_now = ak_private; 562 563 /* See if the new access, via this base, gives more 564 access than our previous best access. */ 565 if (base_access_now != ak_none 566 && (access == ak_none || base_access_now < access)) 567 { 568 access = base_access_now; 569 570 /* If the new access is public, we can't do better. */ 571 if (access == ak_public) 572 break; 573 } 574 } 575 } 576 } 577 578 /* Note the access to DECL in TYPE. */ 579 SET_BINFO_ACCESS (binfo, access); 580 581 return NULL_TREE; 582} 583 584/* Return the access to DECL in TYPE. */ 585 586static access_kind 587access_in_type (tree type, tree decl) 588{ 589 tree binfo = TYPE_BINFO (type); 590 591 /* We must take into account 592 593 [class.paths] 594 595 If a name can be reached by several paths through a multiple 596 inheritance graph, the access is that of the path that gives 597 most access. 598 599 The algorithm we use is to make a post-order depth-first traversal 600 of the base-class hierarchy. As we come up the tree, we annotate 601 each node with the most lenient access. */ 602 dfs_walk_once (binfo, dfs_access_in_type_pre, dfs_access_in_type, decl); 603 604 return BINFO_ACCESS (binfo); 605} 606 607/* Returns nonzero if it is OK to access DECL named in TYPE through an object 608 of OTYPE in the context of DERIVED. */ 609 610static int 611protected_accessible_p (tree decl, tree derived, tree type, tree otype) 612{ 613 /* We're checking this clause from [class.access.base] 614 615 m as a member of N is protected, and the reference occurs in a 616 member or friend of class N, or in a member or friend of a 617 class P derived from N, where m as a member of P is public, private 618 or protected. 619 620 Here DERIVED is a possible P, DECL is m and TYPE is N. */ 621 622 /* If DERIVED isn't derived from N, then it can't be a P. */ 623 if (!DERIVED_FROM_P (type, derived)) 624 return 0; 625 626 /* DECL_NONSTATIC_MEMBER_P won't work for USING_DECLs. */ 627 decl = strip_using_decl (decl); 628 /* We don't expect or support dependent decls. */ 629 gcc_assert (TREE_CODE (decl) != USING_DECL); 630 631 /* [class.protected] 632 633 When a friend or a member function of a derived class references 634 a protected nonstatic member of a base class, an access check 635 applies in addition to those described earlier in clause 636 _class.access_) Except when forming a pointer to member 637 (_expr.unary.op_), the access must be through a pointer to, 638 reference to, or object of the derived class itself (or any class 639 derived from that class) (_expr.ref_). If the access is to form 640 a pointer to member, the nested-name-specifier shall name the 641 derived class (or any class derived from that class). */ 642 if (DECL_NONSTATIC_MEMBER_P (decl) 643 && !DERIVED_FROM_P (derived, otype)) 644 return 0; 645 646 return 1; 647} 648 649/* Returns nonzero if SCOPE is a type or a friend of a type which would be able 650 to access DECL through TYPE. OTYPE is the type of the object. */ 651 652static int 653friend_accessible_p (tree scope, tree decl, tree type, tree otype) 654{ 655 /* We're checking this clause from [class.access.base] 656 657 m as a member of N is protected, and the reference occurs in a 658 member or friend of class N, or in a member or friend of a 659 class P derived from N, where m as a member of P is public, private 660 or protected. 661 662 Here DECL is m and TYPE is N. SCOPE is the current context, 663 and we check all its possible Ps. */ 664 tree befriending_classes; 665 tree t; 666 667 if (!scope) 668 return 0; 669 670 if (is_global_friend (scope)) 671 return 1; 672 673 /* Is SCOPE itself a suitable P? */ 674 if (TYPE_P (scope) && protected_accessible_p (decl, scope, type, otype)) 675 return 1; 676 677 if (DECL_DECLARES_FUNCTION_P (scope)) 678 befriending_classes = DECL_BEFRIENDING_CLASSES (scope); 679 else if (TYPE_P (scope)) 680 befriending_classes = CLASSTYPE_BEFRIENDING_CLASSES (scope); 681 else 682 return 0; 683 684 for (t = befriending_classes; t; t = TREE_CHAIN (t)) 685 if (protected_accessible_p (decl, TREE_VALUE (t), type, otype)) 686 return 1; 687 688 /* Nested classes have the same access as their enclosing types, as 689 per DR 45 (this is a change from C++98). */ 690 if (TYPE_P (scope)) 691 if (friend_accessible_p (TYPE_CONTEXT (scope), decl, type, otype)) 692 return 1; 693 694 if (DECL_DECLARES_FUNCTION_P (scope)) 695 { 696 /* Perhaps this SCOPE is a member of a class which is a 697 friend. */ 698 if (DECL_CLASS_SCOPE_P (scope) 699 && friend_accessible_p (DECL_CONTEXT (scope), decl, type, otype)) 700 return 1; 701 } 702 703 /* Maybe scope's template is a friend. */ 704 if (tree tinfo = get_template_info (scope)) 705 { 706 tree tmpl = TI_TEMPLATE (tinfo); 707 if (DECL_CLASS_TEMPLATE_P (tmpl)) 708 tmpl = TREE_TYPE (tmpl); 709 else 710 tmpl = DECL_TEMPLATE_RESULT (tmpl); 711 if (tmpl != scope) 712 { 713 /* Increment processing_template_decl to make sure that 714 dependent_type_p works correctly. */ 715 ++processing_template_decl; 716 int ret = friend_accessible_p (tmpl, decl, type, otype); 717 --processing_template_decl; 718 if (ret) 719 return 1; 720 } 721 } 722 723 /* If is_friend is true, we should have found a befriending class. */ 724 gcc_checking_assert (!is_friend (type, scope)); 725 726 return 0; 727} 728 729struct dfs_accessible_data 730{ 731 tree decl; 732 tree object_type; 733}; 734 735/* Avoid walking up past a declaration of the member. */ 736 737static tree 738dfs_accessible_pre (tree binfo, void *data) 739{ 740 dfs_accessible_data *d = (dfs_accessible_data *)data; 741 tree type = BINFO_TYPE (binfo); 742 if (member_declared_in_type (d->decl, type)) 743 return dfs_skip_bases; 744 return NULL_TREE; 745} 746 747/* Called via dfs_walk_once_accessible from accessible_p */ 748 749static tree 750dfs_accessible_post (tree binfo, void *data) 751{ 752 /* access_in_type already set BINFO_ACCESS for us. */ 753 access_kind access = BINFO_ACCESS (binfo); 754 tree N = BINFO_TYPE (binfo); 755 dfs_accessible_data *d = (dfs_accessible_data *)data; 756 tree decl = d->decl; 757 tree scope = current_nonlambda_scope (); 758 759 /* A member m is accessible at the point R when named in class N if */ 760 switch (access) 761 { 762 case ak_none: 763 return NULL_TREE; 764 765 case ak_public: 766 /* m as a member of N is public, or */ 767 return binfo; 768 769 case ak_private: 770 { 771 /* m as a member of N is private, and R occurs in a member or friend of 772 class N, or */ 773 if (scope && TREE_CODE (scope) != NAMESPACE_DECL 774 && is_friend (N, scope)) 775 return binfo; 776 return NULL_TREE; 777 } 778 779 case ak_protected: 780 { 781 /* m as a member of N is protected, and R occurs in a member or friend 782 of class N, or in a member or friend of a class P derived from N, 783 where m as a member of P is public, private, or protected */ 784 if (friend_accessible_p (scope, decl, N, d->object_type)) 785 return binfo; 786 return NULL_TREE; 787 } 788 789 default: 790 gcc_unreachable (); 791 } 792} 793 794/* Like accessible_p below, but within a template returns true iff DECL is 795 accessible in TYPE to all possible instantiations of the template. */ 796 797int 798accessible_in_template_p (tree type, tree decl) 799{ 800 int save_ptd = processing_template_decl; 801 processing_template_decl = 0; 802 int val = accessible_p (type, decl, false); 803 processing_template_decl = save_ptd; 804 return val; 805} 806 807/* DECL is a declaration from a base class of TYPE, which was the 808 class used to name DECL. Return nonzero if, in the current 809 context, DECL is accessible. If TYPE is actually a BINFO node, 810 then we can tell in what context the access is occurring by looking 811 at the most derived class along the path indicated by BINFO. If 812 CONSIDER_LOCAL is true, do consider special access the current 813 scope or friendship thereof we might have. */ 814 815int 816accessible_p (tree type, tree decl, bool consider_local_p) 817{ 818 tree binfo; 819 access_kind access; 820 821 /* If this declaration is in a block or namespace scope, there's no 822 access control. */ 823 if (!TYPE_P (context_for_name_lookup (decl))) 824 return 1; 825 826 /* There is no need to perform access checks inside a thunk. */ 827 if (current_function_decl && DECL_THUNK_P (current_function_decl)) 828 return 1; 829 830 /* In a template declaration, we cannot be sure whether the 831 particular specialization that is instantiated will be a friend 832 or not. Therefore, all access checks are deferred until 833 instantiation. However, PROCESSING_TEMPLATE_DECL is set in the 834 parameter list for a template (because we may see dependent types 835 in default arguments for template parameters), and access 836 checking should be performed in the outermost parameter list. */ 837 if (processing_template_decl 838 && !expanding_concept () 839 && (!processing_template_parmlist || processing_template_decl > 1)) 840 return 1; 841 842 tree otype = NULL_TREE; 843 if (!TYPE_P (type)) 844 { 845 /* When accessing a non-static member, the most derived type in the 846 binfo chain is the type of the object; remember that type for 847 protected_accessible_p. */ 848 for (tree b = type; b; b = BINFO_INHERITANCE_CHAIN (b)) 849 otype = BINFO_TYPE (b); 850 type = BINFO_TYPE (type); 851 } 852 else 853 otype = type; 854 855 /* [class.access.base] 856 857 A member m is accessible when named in class N if 858 859 --m as a member of N is public, or 860 861 --m as a member of N is private, and the reference occurs in a 862 member or friend of class N, or 863 864 --m as a member of N is protected, and the reference occurs in a 865 member or friend of class N, or in a member or friend of a 866 class P derived from N, where m as a member of P is public, private or 867 protected, or 868 869 --there exists a base class B of N that is accessible at the point 870 of reference, and m is accessible when named in class B. 871 872 We walk the base class hierarchy, checking these conditions. */ 873 874 /* We walk using TYPE_BINFO (type) because access_in_type will set 875 BINFO_ACCESS on it and its bases. */ 876 binfo = TYPE_BINFO (type); 877 878 /* Compute the accessibility of DECL in the class hierarchy 879 dominated by type. */ 880 access = access_in_type (type, decl); 881 if (access == ak_public) 882 return 1; 883 884 /* If we aren't considering the point of reference, only the first bullet 885 applies. */ 886 if (!consider_local_p) 887 return 0; 888 889 dfs_accessible_data d = { decl, otype }; 890 891 /* Walk the hierarchy again, looking for a base class that allows 892 access. */ 893 return dfs_walk_once_accessible (binfo, /*friends=*/true, 894 dfs_accessible_pre, 895 dfs_accessible_post, &d) 896 != NULL_TREE; 897} 898 899struct lookup_field_info { 900 /* The type in which we're looking. */ 901 tree type; 902 /* The name of the field for which we're looking. */ 903 tree name; 904 /* If non-NULL, the current result of the lookup. */ 905 tree rval; 906 /* The path to RVAL. */ 907 tree rval_binfo; 908 /* If non-NULL, the lookup was ambiguous, and this is a list of the 909 candidates. */ 910 tree ambiguous; 911 /* If nonzero, we are looking for types, not data members. */ 912 int want_type; 913 /* If something went wrong, a message indicating what. */ 914 const char *errstr; 915}; 916 917/* Nonzero for a class member means that it is shared between all objects 918 of that class. 919 920 [class.member.lookup]:If the resulting set of declarations are not all 921 from sub-objects of the same type, or the set has a nonstatic member 922 and includes members from distinct sub-objects, there is an ambiguity 923 and the program is ill-formed. 924 925 This function checks that T contains no nonstatic members. */ 926 927int 928shared_member_p (tree t) 929{ 930 if (VAR_P (t) || TREE_CODE (t) == TYPE_DECL \ 931 || TREE_CODE (t) == CONST_DECL) 932 return 1; 933 if (is_overloaded_fn (t)) 934 { 935 for (ovl_iterator iter (get_fns (t)); iter; ++iter) 936 { 937 tree decl = strip_using_decl (*iter); 938 /* We don't expect or support dependent decls. */ 939 gcc_assert (TREE_CODE (decl) != USING_DECL); 940 if (DECL_NONSTATIC_MEMBER_FUNCTION_P (decl)) 941 return 0; 942 } 943 return 1; 944 } 945 return 0; 946} 947 948/* Routine to see if the sub-object denoted by the binfo PARENT can be 949 found as a base class and sub-object of the object denoted by 950 BINFO. */ 951 952static int 953is_subobject_of_p (tree parent, tree binfo) 954{ 955 tree probe; 956 957 for (probe = parent; probe; probe = BINFO_INHERITANCE_CHAIN (probe)) 958 { 959 if (probe == binfo) 960 return 1; 961 if (BINFO_VIRTUAL_P (probe)) 962 return (binfo_for_vbase (BINFO_TYPE (probe), BINFO_TYPE (binfo)) 963 != NULL_TREE); 964 } 965 return 0; 966} 967 968/* DATA is really a struct lookup_field_info. Look for a field with 969 the name indicated there in BINFO. If this function returns a 970 non-NULL value it is the result of the lookup. Called from 971 lookup_field via breadth_first_search. */ 972 973static tree 974lookup_field_r (tree binfo, void *data) 975{ 976 struct lookup_field_info *lfi = (struct lookup_field_info *) data; 977 tree type = BINFO_TYPE (binfo); 978 tree nval = NULL_TREE; 979 980 /* If this is a dependent base, don't look in it. */ 981 if (BINFO_DEPENDENT_BASE_P (binfo)) 982 return NULL_TREE; 983 984 /* If this base class is hidden by the best-known value so far, we 985 don't need to look. */ 986 if (lfi->rval_binfo && BINFO_INHERITANCE_CHAIN (binfo) == lfi->rval_binfo 987 && !BINFO_VIRTUAL_P (binfo)) 988 return dfs_skip_bases; 989 990 nval = get_class_binding (type, lfi->name, lfi->want_type); 991 992 /* If we're looking up a type (as with an elaborated type specifier) 993 we ignore all non-types we find. */ 994 if (lfi->want_type && nval && !DECL_DECLARES_TYPE_P (nval)) 995 { 996 nval = NULL_TREE; 997 if (CLASSTYPE_NESTED_UTDS (type)) 998 if (binding_entry e = binding_table_find (CLASSTYPE_NESTED_UTDS (type), 999 lfi->name)) 1000 nval = TYPE_MAIN_DECL (e->type); 1001 } 1002 1003 /* If there is no declaration with the indicated name in this type, 1004 then there's nothing to do. */ 1005 if (!nval) 1006 goto done; 1007 1008 /* If the lookup already found a match, and the new value doesn't 1009 hide the old one, we might have an ambiguity. */ 1010 if (lfi->rval_binfo 1011 && !is_subobject_of_p (lfi->rval_binfo, binfo)) 1012 1013 { 1014 if (nval == lfi->rval && shared_member_p (nval)) 1015 /* The two things are really the same. */ 1016 ; 1017 else if (is_subobject_of_p (binfo, lfi->rval_binfo)) 1018 /* The previous value hides the new one. */ 1019 ; 1020 else 1021 { 1022 /* We have a real ambiguity. We keep a chain of all the 1023 candidates. */ 1024 if (!lfi->ambiguous && lfi->rval) 1025 { 1026 /* This is the first time we noticed an ambiguity. Add 1027 what we previously thought was a reasonable candidate 1028 to the list. */ 1029 lfi->ambiguous = tree_cons (NULL_TREE, lfi->rval, NULL_TREE); 1030 TREE_TYPE (lfi->ambiguous) = error_mark_node; 1031 } 1032 1033 /* Add the new value. */ 1034 lfi->ambiguous = tree_cons (NULL_TREE, nval, lfi->ambiguous); 1035 TREE_TYPE (lfi->ambiguous) = error_mark_node; 1036 lfi->errstr = G_("request for member %qD is ambiguous"); 1037 } 1038 } 1039 else 1040 { 1041 lfi->rval = nval; 1042 lfi->rval_binfo = binfo; 1043 } 1044 1045 done: 1046 /* Don't look for constructors or destructors in base classes. */ 1047 if (IDENTIFIER_CDTOR_P (lfi->name)) 1048 return dfs_skip_bases; 1049 return NULL_TREE; 1050} 1051 1052/* Return a "baselink" with BASELINK_BINFO, BASELINK_ACCESS_BINFO, 1053 BASELINK_FUNCTIONS, and BASELINK_OPTYPE set to BINFO, ACCESS_BINFO, 1054 FUNCTIONS, and OPTYPE respectively. */ 1055 1056tree 1057build_baselink (tree binfo, tree access_binfo, tree functions, tree optype) 1058{ 1059 tree baselink; 1060 1061 gcc_assert (TREE_CODE (functions) == FUNCTION_DECL 1062 || TREE_CODE (functions) == TEMPLATE_DECL 1063 || TREE_CODE (functions) == TEMPLATE_ID_EXPR 1064 || TREE_CODE (functions) == OVERLOAD); 1065 gcc_assert (!optype || TYPE_P (optype)); 1066 gcc_assert (TREE_TYPE (functions)); 1067 1068 baselink = make_node (BASELINK); 1069 TREE_TYPE (baselink) = TREE_TYPE (functions); 1070 BASELINK_BINFO (baselink) = binfo; 1071 BASELINK_ACCESS_BINFO (baselink) = access_binfo; 1072 BASELINK_FUNCTIONS (baselink) = functions; 1073 BASELINK_OPTYPE (baselink) = optype; 1074 1075 return baselink; 1076} 1077 1078/* Look for a member named NAME in an inheritance lattice dominated by 1079 XBASETYPE. If PROTECT is 0 or two, we do not check access. If it 1080 is 1, we enforce accessibility. If PROTECT is zero, then, for an 1081 ambiguous lookup, we return NULL. If PROTECT is 1, we issue error 1082 messages about inaccessible or ambiguous lookup. If PROTECT is 2, 1083 we return a TREE_LIST whose TREE_TYPE is error_mark_node and whose 1084 TREE_VALUEs are the list of ambiguous candidates. 1085 1086 WANT_TYPE is 1 when we should only return TYPE_DECLs. 1087 1088 If nothing can be found return NULL_TREE and do not issue an error. 1089 1090 If non-NULL, failure information is written back to AFI. */ 1091 1092tree 1093lookup_member (tree xbasetype, tree name, int protect, bool want_type, 1094 tsubst_flags_t complain, access_failure_info *afi) 1095{ 1096 tree rval, rval_binfo = NULL_TREE; 1097 tree type = NULL_TREE, basetype_path = NULL_TREE; 1098 struct lookup_field_info lfi; 1099 1100 /* rval_binfo is the binfo associated with the found member, note, 1101 this can be set with useful information, even when rval is not 1102 set, because it must deal with ALL members, not just non-function 1103 members. It is used for ambiguity checking and the hidden 1104 checks. Whereas rval is only set if a proper (not hidden) 1105 non-function member is found. */ 1106 1107 const char *errstr = 0; 1108 1109 if (name == error_mark_node 1110 || xbasetype == NULL_TREE 1111 || xbasetype == error_mark_node) 1112 return NULL_TREE; 1113 1114 gcc_assert (identifier_p (name)); 1115 1116 if (TREE_CODE (xbasetype) == TREE_BINFO) 1117 { 1118 type = BINFO_TYPE (xbasetype); 1119 basetype_path = xbasetype; 1120 } 1121 else 1122 { 1123 if (!RECORD_OR_UNION_CODE_P (TREE_CODE (xbasetype))) 1124 return NULL_TREE; 1125 type = xbasetype; 1126 xbasetype = NULL_TREE; 1127 } 1128 1129 type = complete_type (type); 1130 1131 /* Make sure we're looking for a member of the current instantiation in the 1132 right partial specialization. */ 1133 if (dependent_type_p (type)) 1134 if (tree t = currently_open_class (type)) 1135 type = t; 1136 1137 if (!basetype_path) 1138 basetype_path = TYPE_BINFO (type); 1139 1140 if (!basetype_path) 1141 return NULL_TREE; 1142 1143 memset (&lfi, 0, sizeof (lfi)); 1144 lfi.type = type; 1145 lfi.name = name; 1146 lfi.want_type = want_type; 1147 dfs_walk_all (basetype_path, &lookup_field_r, NULL, &lfi); 1148 rval = lfi.rval; 1149 rval_binfo = lfi.rval_binfo; 1150 if (rval_binfo) 1151 type = BINFO_TYPE (rval_binfo); 1152 errstr = lfi.errstr; 1153 1154 /* If we are not interested in ambiguities, don't report them; 1155 just return NULL_TREE. */ 1156 if (!protect && lfi.ambiguous) 1157 return NULL_TREE; 1158 1159 if (protect == 2) 1160 { 1161 if (lfi.ambiguous) 1162 return lfi.ambiguous; 1163 else 1164 protect = 0; 1165 } 1166 1167 /* [class.access] 1168 1169 In the case of overloaded function names, access control is 1170 applied to the function selected by overloaded resolution. 1171 1172 We cannot check here, even if RVAL is only a single non-static 1173 member function, since we do not know what the "this" pointer 1174 will be. For: 1175 1176 class A { protected: void f(); }; 1177 class B : public A { 1178 void g(A *p) { 1179 f(); // OK 1180 p->f(); // Not OK. 1181 } 1182 }; 1183 1184 only the first call to "f" is valid. However, if the function is 1185 static, we can check. */ 1186 if (rval && protect 1187 && !really_overloaded_fn (rval)) 1188 { 1189 tree decl = is_overloaded_fn (rval) ? get_first_fn (rval) : rval; 1190 decl = strip_using_decl (decl); 1191 /* A dependent USING_DECL will be checked after tsubsting. */ 1192 if (TREE_CODE (decl) != USING_DECL 1193 && !DECL_NONSTATIC_MEMBER_FUNCTION_P (decl) 1194 && !perform_or_defer_access_check (basetype_path, decl, decl, 1195 complain, afi)) 1196 rval = error_mark_node; 1197 } 1198 1199 if (errstr && protect) 1200 { 1201 if (complain & tf_error) 1202 { 1203 error (errstr, name, type); 1204 if (lfi.ambiguous) 1205 print_candidates (lfi.ambiguous); 1206 } 1207 rval = error_mark_node; 1208 } 1209 1210 if (rval && is_overloaded_fn (rval)) 1211 rval = build_baselink (rval_binfo, basetype_path, rval, 1212 (IDENTIFIER_CONV_OP_P (name) 1213 ? TREE_TYPE (name): NULL_TREE)); 1214 return rval; 1215} 1216 1217/* Helper class for lookup_member_fuzzy. */ 1218 1219class lookup_field_fuzzy_info 1220{ 1221 public: 1222 lookup_field_fuzzy_info (bool want_type_p) : 1223 m_want_type_p (want_type_p), m_candidates () {} 1224 1225 void fuzzy_lookup_field (tree type); 1226 1227 /* If true, we are looking for types, not data members. */ 1228 bool m_want_type_p; 1229 /* The result: a vec of identifiers. */ 1230 auto_vec<tree> m_candidates; 1231}; 1232 1233/* Locate all fields within TYPE, append them to m_candidates. */ 1234 1235void 1236lookup_field_fuzzy_info::fuzzy_lookup_field (tree type) 1237{ 1238 if (!CLASS_TYPE_P (type)) 1239 return; 1240 1241 for (tree field = TYPE_FIELDS (type); field; field = DECL_CHAIN (field)) 1242 { 1243 if (m_want_type_p && !DECL_DECLARES_TYPE_P (field)) 1244 continue; 1245 1246 if (!DECL_NAME (field)) 1247 continue; 1248 1249 if (is_lambda_ignored_entity (field)) 1250 continue; 1251 1252 m_candidates.safe_push (DECL_NAME (field)); 1253 } 1254} 1255 1256 1257/* Helper function for lookup_member_fuzzy, called via dfs_walk_all 1258 DATA is really a lookup_field_fuzzy_info. Look for a field with 1259 the name indicated there in BINFO. Gathers pertinent identifiers into 1260 m_candidates. */ 1261 1262static tree 1263lookup_field_fuzzy_r (tree binfo, void *data) 1264{ 1265 lookup_field_fuzzy_info *lffi = (lookup_field_fuzzy_info *) data; 1266 tree type = BINFO_TYPE (binfo); 1267 1268 lffi->fuzzy_lookup_field (type); 1269 1270 return NULL_TREE; 1271} 1272 1273/* Like lookup_member, but try to find the closest match for NAME, 1274 rather than an exact match, and return an identifier (or NULL_TREE). 1275 Do not complain. */ 1276 1277tree 1278lookup_member_fuzzy (tree xbasetype, tree name, bool want_type_p) 1279{ 1280 tree type = NULL_TREE, basetype_path = NULL_TREE; 1281 struct lookup_field_fuzzy_info lffi (want_type_p); 1282 1283 /* rval_binfo is the binfo associated with the found member, note, 1284 this can be set with useful information, even when rval is not 1285 set, because it must deal with ALL members, not just non-function 1286 members. It is used for ambiguity checking and the hidden 1287 checks. Whereas rval is only set if a proper (not hidden) 1288 non-function member is found. */ 1289 1290 if (name == error_mark_node 1291 || xbasetype == NULL_TREE 1292 || xbasetype == error_mark_node) 1293 return NULL_TREE; 1294 1295 gcc_assert (identifier_p (name)); 1296 1297 if (TREE_CODE (xbasetype) == TREE_BINFO) 1298 { 1299 type = BINFO_TYPE (xbasetype); 1300 basetype_path = xbasetype; 1301 } 1302 else 1303 { 1304 if (!RECORD_OR_UNION_CODE_P (TREE_CODE (xbasetype))) 1305 return NULL_TREE; 1306 type = xbasetype; 1307 xbasetype = NULL_TREE; 1308 } 1309 1310 type = complete_type (type); 1311 1312 /* Make sure we're looking for a member of the current instantiation in the 1313 right partial specialization. */ 1314 if (flag_concepts && dependent_type_p (type)) 1315 type = currently_open_class (type); 1316 1317 if (!basetype_path) 1318 basetype_path = TYPE_BINFO (type); 1319 1320 if (!basetype_path) 1321 return NULL_TREE; 1322 1323 /* Populate lffi.m_candidates. */ 1324 dfs_walk_all (basetype_path, &lookup_field_fuzzy_r, NULL, &lffi); 1325 1326 return find_closest_identifier (name, &lffi.m_candidates); 1327} 1328 1329/* Like lookup_member, except that if we find a function member we 1330 return NULL_TREE. */ 1331 1332tree 1333lookup_field (tree xbasetype, tree name, int protect, bool want_type) 1334{ 1335 tree rval = lookup_member (xbasetype, name, protect, want_type, 1336 tf_warning_or_error); 1337 1338 /* Ignore functions, but propagate the ambiguity list. */ 1339 if (!error_operand_p (rval) 1340 && (rval && BASELINK_P (rval))) 1341 return NULL_TREE; 1342 1343 return rval; 1344} 1345 1346/* Like lookup_member, except that if we find a non-function member we 1347 return NULL_TREE. */ 1348 1349tree 1350lookup_fnfields (tree xbasetype, tree name, int protect) 1351{ 1352 tree rval = lookup_member (xbasetype, name, protect, /*want_type=*/false, 1353 tf_warning_or_error); 1354 1355 /* Ignore non-functions, but propagate the ambiguity list. */ 1356 if (!error_operand_p (rval) 1357 && (rval && !BASELINK_P (rval))) 1358 return NULL_TREE; 1359 1360 return rval; 1361} 1362 1363/* DECL is the result of a qualified name lookup. QUALIFYING_SCOPE is 1364 the class or namespace used to qualify the name. CONTEXT_CLASS is 1365 the class corresponding to the object in which DECL will be used. 1366 Return a possibly modified version of DECL that takes into account 1367 the CONTEXT_CLASS. 1368 1369 In particular, consider an expression like `B::m' in the context of 1370 a derived class `D'. If `B::m' has been resolved to a BASELINK, 1371 then the most derived class indicated by the BASELINK_BINFO will be 1372 `B', not `D'. This function makes that adjustment. */ 1373 1374tree 1375adjust_result_of_qualified_name_lookup (tree decl, 1376 tree qualifying_scope, 1377 tree context_class) 1378{ 1379 if (context_class && context_class != error_mark_node 1380 && CLASS_TYPE_P (context_class) 1381 && CLASS_TYPE_P (qualifying_scope) 1382 && DERIVED_FROM_P (qualifying_scope, context_class) 1383 && BASELINK_P (decl)) 1384 { 1385 tree base; 1386 1387 /* Look for the QUALIFYING_SCOPE as a base of the CONTEXT_CLASS. 1388 Because we do not yet know which function will be chosen by 1389 overload resolution, we cannot yet check either accessibility 1390 or ambiguity -- in either case, the choice of a static member 1391 function might make the usage valid. */ 1392 base = lookup_base (context_class, qualifying_scope, 1393 ba_unique, NULL, tf_none); 1394 if (base && base != error_mark_node) 1395 { 1396 BASELINK_ACCESS_BINFO (decl) = base; 1397 tree decl_binfo 1398 = lookup_base (base, BINFO_TYPE (BASELINK_BINFO (decl)), 1399 ba_unique, NULL, tf_none); 1400 if (decl_binfo && decl_binfo != error_mark_node) 1401 BASELINK_BINFO (decl) = decl_binfo; 1402 } 1403 } 1404 1405 if (BASELINK_P (decl)) 1406 BASELINK_QUALIFIED_P (decl) = true; 1407 1408 return decl; 1409} 1410 1411 1412/* Walk the class hierarchy within BINFO, in a depth-first traversal. 1413 PRE_FN is called in preorder, while POST_FN is called in postorder. 1414 If PRE_FN returns DFS_SKIP_BASES, child binfos will not be 1415 walked. If PRE_FN or POST_FN returns a different non-NULL value, 1416 that value is immediately returned and the walk is terminated. One 1417 of PRE_FN and POST_FN can be NULL. At each node, PRE_FN and 1418 POST_FN are passed the binfo to examine and the caller's DATA 1419 value. All paths are walked, thus virtual and morally virtual 1420 binfos can be multiply walked. */ 1421 1422tree 1423dfs_walk_all (tree binfo, tree (*pre_fn) (tree, void *), 1424 tree (*post_fn) (tree, void *), void *data) 1425{ 1426 tree rval; 1427 unsigned ix; 1428 tree base_binfo; 1429 1430 /* Call the pre-order walking function. */ 1431 if (pre_fn) 1432 { 1433 rval = pre_fn (binfo, data); 1434 if (rval) 1435 { 1436 if (rval == dfs_skip_bases) 1437 goto skip_bases; 1438 return rval; 1439 } 1440 } 1441 1442 /* Find the next child binfo to walk. */ 1443 for (ix = 0; BINFO_BASE_ITERATE (binfo, ix, base_binfo); ix++) 1444 { 1445 rval = dfs_walk_all (base_binfo, pre_fn, post_fn, data); 1446 if (rval) 1447 return rval; 1448 } 1449 1450 skip_bases: 1451 /* Call the post-order walking function. */ 1452 if (post_fn) 1453 { 1454 rval = post_fn (binfo, data); 1455 gcc_assert (rval != dfs_skip_bases); 1456 return rval; 1457 } 1458 1459 return NULL_TREE; 1460} 1461 1462/* Worker for dfs_walk_once. This behaves as dfs_walk_all, except 1463 that binfos are walked at most once. */ 1464 1465static tree 1466dfs_walk_once_r (tree binfo, tree (*pre_fn) (tree, void *), 1467 tree (*post_fn) (tree, void *), hash_set<tree> *pset, 1468 void *data) 1469{ 1470 tree rval; 1471 unsigned ix; 1472 tree base_binfo; 1473 1474 /* Call the pre-order walking function. */ 1475 if (pre_fn) 1476 { 1477 rval = pre_fn (binfo, data); 1478 if (rval) 1479 { 1480 if (rval == dfs_skip_bases) 1481 goto skip_bases; 1482 1483 return rval; 1484 } 1485 } 1486 1487 /* Find the next child binfo to walk. */ 1488 for (ix = 0; BINFO_BASE_ITERATE (binfo, ix, base_binfo); ix++) 1489 { 1490 if (BINFO_VIRTUAL_P (base_binfo)) 1491 if (pset->add (base_binfo)) 1492 continue; 1493 1494 rval = dfs_walk_once_r (base_binfo, pre_fn, post_fn, pset, data); 1495 if (rval) 1496 return rval; 1497 } 1498 1499 skip_bases: 1500 /* Call the post-order walking function. */ 1501 if (post_fn) 1502 { 1503 rval = post_fn (binfo, data); 1504 gcc_assert (rval != dfs_skip_bases); 1505 return rval; 1506 } 1507 1508 return NULL_TREE; 1509} 1510 1511/* Like dfs_walk_all, except that binfos are not multiply walked. For 1512 non-diamond shaped hierarchies this is the same as dfs_walk_all. 1513 For diamond shaped hierarchies we must mark the virtual bases, to 1514 avoid multiple walks. */ 1515 1516tree 1517dfs_walk_once (tree binfo, tree (*pre_fn) (tree, void *), 1518 tree (*post_fn) (tree, void *), void *data) 1519{ 1520 static int active = 0; /* We must not be called recursively. */ 1521 tree rval; 1522 1523 gcc_assert (pre_fn || post_fn); 1524 gcc_assert (!active); 1525 active++; 1526 1527 if (!CLASSTYPE_DIAMOND_SHAPED_P (BINFO_TYPE (binfo))) 1528 /* We are not diamond shaped, and therefore cannot encounter the 1529 same binfo twice. */ 1530 rval = dfs_walk_all (binfo, pre_fn, post_fn, data); 1531 else 1532 { 1533 hash_set<tree> pset; 1534 rval = dfs_walk_once_r (binfo, pre_fn, post_fn, &pset, data); 1535 } 1536 1537 active--; 1538 1539 return rval; 1540} 1541 1542/* Worker function for dfs_walk_once_accessible. Behaves like 1543 dfs_walk_once_r, except (a) FRIENDS_P is true if special 1544 access given by the current context should be considered, (b) ONCE 1545 indicates whether bases should be marked during traversal. */ 1546 1547static tree 1548dfs_walk_once_accessible_r (tree binfo, bool friends_p, hash_set<tree> *pset, 1549 tree (*pre_fn) (tree, void *), 1550 tree (*post_fn) (tree, void *), void *data) 1551{ 1552 tree rval = NULL_TREE; 1553 unsigned ix; 1554 tree base_binfo; 1555 1556 /* Call the pre-order walking function. */ 1557 if (pre_fn) 1558 { 1559 rval = pre_fn (binfo, data); 1560 if (rval) 1561 { 1562 if (rval == dfs_skip_bases) 1563 goto skip_bases; 1564 1565 return rval; 1566 } 1567 } 1568 1569 /* Find the next child binfo to walk. */ 1570 for (ix = 0; BINFO_BASE_ITERATE (binfo, ix, base_binfo); ix++) 1571 { 1572 bool mark = pset && BINFO_VIRTUAL_P (base_binfo); 1573 1574 if (mark && pset->contains (base_binfo)) 1575 continue; 1576 1577 /* If the base is inherited via private or protected 1578 inheritance, then we can't see it, unless we are a friend of 1579 the current binfo. */ 1580 if (BINFO_BASE_ACCESS (binfo, ix) != access_public_node) 1581 { 1582 tree scope; 1583 if (!friends_p) 1584 continue; 1585 scope = current_scope (); 1586 if (!scope 1587 || TREE_CODE (scope) == NAMESPACE_DECL 1588 || !is_friend (BINFO_TYPE (binfo), scope)) 1589 continue; 1590 } 1591 1592 if (mark) 1593 pset->add (base_binfo); 1594 1595 rval = dfs_walk_once_accessible_r (base_binfo, friends_p, pset, 1596 pre_fn, post_fn, data); 1597 if (rval) 1598 return rval; 1599 } 1600 1601 skip_bases: 1602 /* Call the post-order walking function. */ 1603 if (post_fn) 1604 { 1605 rval = post_fn (binfo, data); 1606 gcc_assert (rval != dfs_skip_bases); 1607 return rval; 1608 } 1609 1610 return NULL_TREE; 1611} 1612 1613/* Like dfs_walk_once except that only accessible bases are walked. 1614 FRIENDS_P indicates whether friendship of the local context 1615 should be considered when determining accessibility. */ 1616 1617static tree 1618dfs_walk_once_accessible (tree binfo, bool friends_p, 1619 tree (*pre_fn) (tree, void *), 1620 tree (*post_fn) (tree, void *), void *data) 1621{ 1622 hash_set<tree> *pset = NULL; 1623 if (CLASSTYPE_DIAMOND_SHAPED_P (BINFO_TYPE (binfo))) 1624 pset = new hash_set<tree>; 1625 tree rval = dfs_walk_once_accessible_r (binfo, friends_p, pset, 1626 pre_fn, post_fn, data); 1627 1628 if (pset) 1629 delete pset; 1630 return rval; 1631} 1632 1633/* Return true iff the code of T is CODE, and it has compatible 1634 type with TYPE. */ 1635 1636static bool 1637matches_code_and_type_p (tree t, enum tree_code code, tree type) 1638{ 1639 if (TREE_CODE (t) != code) 1640 return false; 1641 if (!cxx_types_compatible_p (TREE_TYPE (t), type)) 1642 return false; 1643 return true; 1644} 1645 1646/* Subroutine of direct_accessor_p and reference_accessor_p. 1647 Determine if COMPONENT_REF is a simple field lookup of this->FIELD_DECL. 1648 We expect a tree of the form: 1649 <component_ref: 1650 <indirect_ref:S> 1651 <nop_expr:P* 1652 <parm_decl (this)> 1653 <field_decl (FIELD_DECL)>>>. */ 1654 1655static bool 1656field_access_p (tree component_ref, tree field_decl, tree field_type) 1657{ 1658 if (!matches_code_and_type_p (component_ref, COMPONENT_REF, field_type)) 1659 return false; 1660 1661 tree indirect_ref = TREE_OPERAND (component_ref, 0); 1662 if (!INDIRECT_REF_P (indirect_ref)) 1663 return false; 1664 1665 tree ptr = STRIP_NOPS (TREE_OPERAND (indirect_ref, 0)); 1666 if (!is_this_parameter (ptr)) 1667 return false; 1668 1669 /* Must access the correct field. */ 1670 if (TREE_OPERAND (component_ref, 1) != field_decl) 1671 return false; 1672 return true; 1673} 1674 1675/* Subroutine of field_accessor_p. 1676 1677 Assuming that INIT_EXPR has already had its code and type checked, 1678 determine if it is a simple accessor for FIELD_DECL 1679 (of type FIELD_TYPE). 1680 1681 Specifically, a simple accessor within struct S of the form: 1682 T get_field () { return m_field; } 1683 should have a constexpr_fn_retval (saved_tree) of the form: 1684 <init_expr:T 1685 <result_decl:T 1686 <nop_expr:T 1687 <component_ref: 1688 <indirect_ref:S> 1689 <nop_expr:P* 1690 <parm_decl (this)> 1691 <field_decl (FIELD_DECL)>>>>>. */ 1692 1693static bool 1694direct_accessor_p (tree init_expr, tree field_decl, tree field_type) 1695{ 1696 tree result_decl = TREE_OPERAND (init_expr, 0); 1697 if (!matches_code_and_type_p (result_decl, RESULT_DECL, field_type)) 1698 return false; 1699 1700 tree component_ref = STRIP_NOPS (TREE_OPERAND (init_expr, 1)); 1701 if (!field_access_p (component_ref, field_decl, field_type)) 1702 return false; 1703 1704 return true; 1705} 1706 1707/* Subroutine of field_accessor_p. 1708 1709 Assuming that INIT_EXPR has already had its code and type checked, 1710 determine if it is a "reference" accessor for FIELD_DECL 1711 (of type FIELD_REFERENCE_TYPE). 1712 1713 Specifically, a simple accessor within struct S of the form: 1714 T& get_field () { return m_field; } 1715 should have a constexpr_fn_retval (saved_tree) of the form: 1716 <init_expr:T& 1717 <result_decl:T& 1718 <nop_expr: T& 1719 <addr_expr: T* 1720 <component_ref:T 1721 <indirect_ref:S 1722 <nop_expr 1723 <parm_decl (this)>> 1724 <field (FIELD_DECL)>>>>>>. */ 1725static bool 1726reference_accessor_p (tree init_expr, tree field_decl, tree field_type, 1727 tree field_reference_type) 1728{ 1729 tree result_decl = TREE_OPERAND (init_expr, 0); 1730 if (!matches_code_and_type_p (result_decl, RESULT_DECL, field_reference_type)) 1731 return false; 1732 1733 tree field_pointer_type = build_pointer_type (field_type); 1734 tree addr_expr = STRIP_NOPS (TREE_OPERAND (init_expr, 1)); 1735 if (!matches_code_and_type_p (addr_expr, ADDR_EXPR, field_pointer_type)) 1736 return false; 1737 1738 tree component_ref = STRIP_NOPS (TREE_OPERAND (addr_expr, 0)); 1739 1740 if (!field_access_p (component_ref, field_decl, field_type)) 1741 return false; 1742 1743 return true; 1744} 1745 1746/* Return true if FN is an accessor method for FIELD_DECL. 1747 i.e. a method of the form { return FIELD; }, with no 1748 conversions. 1749 1750 If CONST_P, then additionally require that FN be a const 1751 method. */ 1752 1753static bool 1754field_accessor_p (tree fn, tree field_decl, bool const_p) 1755{ 1756 if (TREE_CODE (fn) != FUNCTION_DECL) 1757 return false; 1758 1759 /* We don't yet support looking up static data, just fields. */ 1760 if (TREE_CODE (field_decl) != FIELD_DECL) 1761 return false; 1762 1763 tree fntype = TREE_TYPE (fn); 1764 if (TREE_CODE (fntype) != METHOD_TYPE) 1765 return false; 1766 1767 /* If the field is accessed via a const "this" argument, verify 1768 that the "this" parameter is const. */ 1769 if (const_p) 1770 { 1771 tree this_class = class_of_this_parm (fntype); 1772 if (!TYPE_READONLY (this_class)) 1773 return false; 1774 } 1775 1776 tree saved_tree = DECL_SAVED_TREE (fn); 1777 1778 if (saved_tree == NULL_TREE) 1779 return false; 1780 1781 /* Attempt to extract a single return value from the function, 1782 if it has one. */ 1783 tree retval = constexpr_fn_retval (saved_tree); 1784 if (retval == NULL_TREE || retval == error_mark_node) 1785 return false; 1786 /* Require an INIT_EXPR. */ 1787 if (TREE_CODE (retval) != INIT_EXPR) 1788 return false; 1789 tree init_expr = retval; 1790 1791 /* Determine if this is a simple accessor within struct S of the form: 1792 T get_field () { return m_field; }. */ 1793 tree field_type = TREE_TYPE (field_decl); 1794 if (cxx_types_compatible_p (TREE_TYPE (init_expr), field_type)) 1795 return direct_accessor_p (init_expr, field_decl, field_type); 1796 1797 /* Failing that, determine if it is an accessor of the form: 1798 T& get_field () { return m_field; }. */ 1799 tree field_reference_type = cp_build_reference_type (field_type, false); 1800 if (cxx_types_compatible_p (TREE_TYPE (init_expr), field_reference_type)) 1801 return reference_accessor_p (init_expr, field_decl, field_type, 1802 field_reference_type); 1803 1804 return false; 1805} 1806 1807/* Callback data for dfs_locate_field_accessor_pre. */ 1808 1809struct locate_field_data 1810{ 1811 locate_field_data (tree field_decl_, bool const_p_) 1812 : field_decl (field_decl_), const_p (const_p_) {} 1813 1814 tree field_decl; 1815 bool const_p; 1816}; 1817 1818/* Return a FUNCTION_DECL that is an "accessor" method for DATA, a FIELD_DECL, 1819 callable via binfo, if one exists, otherwise return NULL_TREE. 1820 1821 Callback for dfs_walk_once_accessible for use within 1822 locate_field_accessor. */ 1823 1824static tree 1825dfs_locate_field_accessor_pre (tree binfo, void *data) 1826{ 1827 locate_field_data *lfd = (locate_field_data *)data; 1828 tree type = BINFO_TYPE (binfo); 1829 1830 vec<tree, va_gc> *member_vec; 1831 tree fn; 1832 size_t i; 1833 1834 if (!CLASS_TYPE_P (type)) 1835 return NULL_TREE; 1836 1837 member_vec = CLASSTYPE_MEMBER_VEC (type); 1838 if (!member_vec) 1839 return NULL_TREE; 1840 1841 for (i = 0; vec_safe_iterate (member_vec, i, &fn); ++i) 1842 if (fn) 1843 if (field_accessor_p (fn, lfd->field_decl, lfd->const_p)) 1844 return fn; 1845 1846 return NULL_TREE; 1847} 1848 1849/* Return a FUNCTION_DECL that is an "accessor" method for FIELD_DECL, 1850 callable via BASETYPE_PATH, if one exists, otherwise return NULL_TREE. */ 1851 1852tree 1853locate_field_accessor (tree basetype_path, tree field_decl, bool const_p) 1854{ 1855 if (TREE_CODE (basetype_path) != TREE_BINFO) 1856 return NULL_TREE; 1857 1858 /* Walk the hierarchy, looking for a method of some base class that allows 1859 access to the field. */ 1860 locate_field_data lfd (field_decl, const_p); 1861 return dfs_walk_once_accessible (basetype_path, /*friends=*/true, 1862 dfs_locate_field_accessor_pre, 1863 NULL, &lfd); 1864} 1865 1866/* Check that virtual overrider OVERRIDER is acceptable for base function 1867 BASEFN. Issue diagnostic, and return zero, if unacceptable. */ 1868 1869static int 1870check_final_overrider (tree overrider, tree basefn) 1871{ 1872 tree over_type = TREE_TYPE (overrider); 1873 tree base_type = TREE_TYPE (basefn); 1874 tree over_return = fndecl_declared_return_type (overrider); 1875 tree base_return = fndecl_declared_return_type (basefn); 1876 tree over_throw, base_throw; 1877 1878 int fail = 0; 1879 1880 if (DECL_INVALID_OVERRIDER_P (overrider)) 1881 return 0; 1882 1883 if (same_type_p (base_return, over_return)) 1884 /* OK */; 1885 else if ((CLASS_TYPE_P (over_return) && CLASS_TYPE_P (base_return)) 1886 || (TREE_CODE (base_return) == TREE_CODE (over_return) 1887 && INDIRECT_TYPE_P (base_return))) 1888 { 1889 /* Potentially covariant. */ 1890 unsigned base_quals, over_quals; 1891 1892 fail = !INDIRECT_TYPE_P (base_return); 1893 if (!fail) 1894 { 1895 fail = cp_type_quals (base_return) != cp_type_quals (over_return); 1896 1897 base_return = TREE_TYPE (base_return); 1898 over_return = TREE_TYPE (over_return); 1899 } 1900 base_quals = cp_type_quals (base_return); 1901 over_quals = cp_type_quals (over_return); 1902 1903 if ((base_quals & over_quals) != over_quals) 1904 fail = 1; 1905 1906 if (CLASS_TYPE_P (base_return) && CLASS_TYPE_P (over_return)) 1907 { 1908 /* Strictly speaking, the standard requires the return type to be 1909 complete even if it only differs in cv-quals, but that seems 1910 like a bug in the wording. */ 1911 if (!same_type_ignoring_top_level_qualifiers_p (base_return, 1912 over_return)) 1913 { 1914 tree binfo = lookup_base (over_return, base_return, 1915 ba_check, NULL, tf_none); 1916 1917 if (!binfo || binfo == error_mark_node) 1918 fail = 1; 1919 } 1920 } 1921 else if (can_convert_standard (TREE_TYPE (base_type), 1922 TREE_TYPE (over_type), 1923 tf_warning_or_error)) 1924 /* GNU extension, allow trivial pointer conversions such as 1925 converting to void *, or qualification conversion. */ 1926 { 1927 auto_diagnostic_group d; 1928 if (pedwarn (DECL_SOURCE_LOCATION (overrider), 0, 1929 "invalid covariant return type for %q#D", overrider)) 1930 inform (DECL_SOURCE_LOCATION (basefn), 1931 "overridden function is %q#D", basefn); 1932 } 1933 else 1934 fail = 2; 1935 } 1936 else 1937 fail = 2; 1938 if (!fail) 1939 /* OK */; 1940 else 1941 { 1942 if (fail == 1) 1943 { 1944 auto_diagnostic_group d; 1945 error ("invalid covariant return type for %q+#D", overrider); 1946 inform (DECL_SOURCE_LOCATION (basefn), 1947 "overridden function is %q#D", basefn); 1948 } 1949 else 1950 { 1951 auto_diagnostic_group d; 1952 error ("conflicting return type specified for %q+#D", overrider); 1953 inform (DECL_SOURCE_LOCATION (basefn), 1954 "overridden function is %q#D", basefn); 1955 } 1956 DECL_INVALID_OVERRIDER_P (overrider) = 1; 1957 return 0; 1958 } 1959 1960 /* Check throw specifier is at least as strict. */ 1961 maybe_instantiate_noexcept (basefn); 1962 maybe_instantiate_noexcept (overrider); 1963 base_throw = TYPE_RAISES_EXCEPTIONS (TREE_TYPE (basefn)); 1964 over_throw = TYPE_RAISES_EXCEPTIONS (TREE_TYPE (overrider)); 1965 1966 if (!comp_except_specs (base_throw, over_throw, ce_derived)) 1967 { 1968 auto_diagnostic_group d; 1969 error ("looser throw specifier for %q+#F", overrider); 1970 inform (DECL_SOURCE_LOCATION (basefn), 1971 "overridden function is %q#F", basefn); 1972 DECL_INVALID_OVERRIDER_P (overrider) = 1; 1973 return 0; 1974 } 1975 1976 /* Check for conflicting type attributes. But leave transaction_safe for 1977 set_one_vmethod_tm_attributes. */ 1978 if (!comp_type_attributes (over_type, base_type) 1979 && !tx_safe_fn_type_p (base_type) 1980 && !tx_safe_fn_type_p (over_type)) 1981 { 1982 auto_diagnostic_group d; 1983 error ("conflicting type attributes specified for %q+#D", overrider); 1984 inform (DECL_SOURCE_LOCATION (basefn), 1985 "overridden function is %q#D", basefn); 1986 DECL_INVALID_OVERRIDER_P (overrider) = 1; 1987 return 0; 1988 } 1989 1990 /* A function declared transaction_safe_dynamic that overrides a function 1991 declared transaction_safe (but not transaction_safe_dynamic) is 1992 ill-formed. */ 1993 if (tx_safe_fn_type_p (base_type) 1994 && lookup_attribute ("transaction_safe_dynamic", 1995 DECL_ATTRIBUTES (overrider)) 1996 && !lookup_attribute ("transaction_safe_dynamic", 1997 DECL_ATTRIBUTES (basefn))) 1998 { 1999 auto_diagnostic_group d; 2000 error_at (DECL_SOURCE_LOCATION (overrider), 2001 "%qD declared %<transaction_safe_dynamic%>", overrider); 2002 inform (DECL_SOURCE_LOCATION (basefn), 2003 "overriding %qD declared %<transaction_safe%>", basefn); 2004 } 2005 2006 if (DECL_DELETED_FN (basefn) != DECL_DELETED_FN (overrider)) 2007 { 2008 if (DECL_DELETED_FN (overrider)) 2009 { 2010 auto_diagnostic_group d; 2011 error ("deleted function %q+D overriding non-deleted function", 2012 overrider); 2013 inform (DECL_SOURCE_LOCATION (basefn), 2014 "overridden function is %qD", basefn); 2015 maybe_explain_implicit_delete (overrider); 2016 } 2017 else 2018 { 2019 auto_diagnostic_group d; 2020 error ("non-deleted function %q+D overriding deleted function", 2021 overrider); 2022 inform (DECL_SOURCE_LOCATION (basefn), 2023 "overridden function is %qD", basefn); 2024 } 2025 return 0; 2026 } 2027 if (DECL_FINAL_P (basefn)) 2028 { 2029 auto_diagnostic_group d; 2030 error ("virtual function %q+D overriding final function", overrider); 2031 inform (DECL_SOURCE_LOCATION (basefn), 2032 "overridden function is %qD", basefn); 2033 return 0; 2034 } 2035 return 1; 2036} 2037 2038/* Given a class TYPE, and a function decl FNDECL, look for 2039 virtual functions in TYPE's hierarchy which FNDECL overrides. 2040 We do not look in TYPE itself, only its bases. 2041 2042 Returns nonzero, if we find any. Set FNDECL's DECL_VIRTUAL_P, if we 2043 find that it overrides anything. 2044 2045 We check that every function which is overridden, is correctly 2046 overridden. */ 2047 2048int 2049look_for_overrides (tree type, tree fndecl) 2050{ 2051 tree binfo = TYPE_BINFO (type); 2052 tree base_binfo; 2053 int ix; 2054 int found = 0; 2055 2056 /* A constructor for a class T does not override a function T 2057 in a base class. */ 2058 if (DECL_CONSTRUCTOR_P (fndecl)) 2059 return 0; 2060 2061 for (ix = 0; BINFO_BASE_ITERATE (binfo, ix, base_binfo); ix++) 2062 { 2063 tree basetype = BINFO_TYPE (base_binfo); 2064 2065 if (TYPE_POLYMORPHIC_P (basetype)) 2066 found += look_for_overrides_r (basetype, fndecl); 2067 } 2068 return found; 2069} 2070 2071/* Look in TYPE for virtual functions with the same signature as 2072 FNDECL. */ 2073 2074tree 2075look_for_overrides_here (tree type, tree fndecl) 2076{ 2077 tree ovl = get_class_binding (type, DECL_NAME (fndecl)); 2078 2079 for (ovl_iterator iter (ovl); iter; ++iter) 2080 { 2081 tree fn = *iter; 2082 2083 if (!DECL_VIRTUAL_P (fn)) 2084 /* Not a virtual. */; 2085 else if (DECL_CONTEXT (fn) != type) 2086 /* Introduced with a using declaration. */; 2087 else if (DECL_STATIC_FUNCTION_P (fndecl)) 2088 { 2089 tree btypes = TYPE_ARG_TYPES (TREE_TYPE (fn)); 2090 tree dtypes = TYPE_ARG_TYPES (TREE_TYPE (fndecl)); 2091 if (compparms (TREE_CHAIN (btypes), dtypes)) 2092 return fn; 2093 } 2094 else if (same_signature_p (fndecl, fn)) 2095 return fn; 2096 } 2097 2098 return NULL_TREE; 2099} 2100 2101/* Look in TYPE for virtual functions overridden by FNDECL. Check both 2102 TYPE itself and its bases. */ 2103 2104static int 2105look_for_overrides_r (tree type, tree fndecl) 2106{ 2107 tree fn = look_for_overrides_here (type, fndecl); 2108 if (fn) 2109 { 2110 if (DECL_STATIC_FUNCTION_P (fndecl)) 2111 { 2112 /* A static member function cannot match an inherited 2113 virtual member function. */ 2114 auto_diagnostic_group d; 2115 error ("%q+#D cannot be declared", fndecl); 2116 error (" since %q+#D declared in base class", fn); 2117 } 2118 else 2119 { 2120 /* It's definitely virtual, even if not explicitly set. */ 2121 DECL_VIRTUAL_P (fndecl) = 1; 2122 check_final_overrider (fndecl, fn); 2123 } 2124 return 1; 2125 } 2126 2127 /* We failed to find one declared in this class. Look in its bases. */ 2128 return look_for_overrides (type, fndecl); 2129} 2130 2131/* Called via dfs_walk from dfs_get_pure_virtuals. */ 2132 2133static tree 2134dfs_get_pure_virtuals (tree binfo, void *data) 2135{ 2136 tree type = (tree) data; 2137 2138 /* We're not interested in primary base classes; the derived class 2139 of which they are a primary base will contain the information we 2140 need. */ 2141 if (!BINFO_PRIMARY_P (binfo)) 2142 { 2143 tree virtuals; 2144 2145 for (virtuals = BINFO_VIRTUALS (binfo); 2146 virtuals; 2147 virtuals = TREE_CHAIN (virtuals)) 2148 if (DECL_PURE_VIRTUAL_P (BV_FN (virtuals))) 2149 vec_safe_push (CLASSTYPE_PURE_VIRTUALS (type), BV_FN (virtuals)); 2150 } 2151 2152 return NULL_TREE; 2153} 2154 2155/* Set CLASSTYPE_PURE_VIRTUALS for TYPE. */ 2156 2157void 2158get_pure_virtuals (tree type) 2159{ 2160 /* Clear the CLASSTYPE_PURE_VIRTUALS list; whatever is already there 2161 is going to be overridden. */ 2162 CLASSTYPE_PURE_VIRTUALS (type) = NULL; 2163 /* Now, run through all the bases which are not primary bases, and 2164 collect the pure virtual functions. We look at the vtable in 2165 each class to determine what pure virtual functions are present. 2166 (A primary base is not interesting because the derived class of 2167 which it is a primary base will contain vtable entries for the 2168 pure virtuals in the base class. */ 2169 dfs_walk_once (TYPE_BINFO (type), NULL, dfs_get_pure_virtuals, type); 2170} 2171 2172/* Debug info for C++ classes can get very large; try to avoid 2173 emitting it everywhere. 2174 2175 Note that this optimization wins even when the target supports 2176 BINCL (if only slightly), and reduces the amount of work for the 2177 linker. */ 2178 2179void 2180maybe_suppress_debug_info (tree t) 2181{ 2182 if (write_symbols == NO_DEBUG) 2183 return; 2184 2185 /* We might have set this earlier in cp_finish_decl. */ 2186 TYPE_DECL_SUPPRESS_DEBUG (TYPE_MAIN_DECL (t)) = 0; 2187 2188 /* Always emit the information for each class every time. */ 2189 if (flag_emit_class_debug_always) 2190 return; 2191 2192 /* If we already know how we're handling this class, handle debug info 2193 the same way. */ 2194 if (CLASSTYPE_INTERFACE_KNOWN (t)) 2195 { 2196 if (CLASSTYPE_INTERFACE_ONLY (t)) 2197 TYPE_DECL_SUPPRESS_DEBUG (TYPE_MAIN_DECL (t)) = 1; 2198 /* else don't set it. */ 2199 } 2200 /* If the class has a vtable, write out the debug info along with 2201 the vtable. */ 2202 else if (TYPE_CONTAINS_VPTR_P (t)) 2203 TYPE_DECL_SUPPRESS_DEBUG (TYPE_MAIN_DECL (t)) = 1; 2204 2205 /* Otherwise, just emit the debug info normally. */ 2206} 2207 2208/* Note that we want debugging information for a base class of a class 2209 whose vtable is being emitted. Normally, this would happen because 2210 calling the constructor for a derived class implies calling the 2211 constructors for all bases, which involve initializing the 2212 appropriate vptr with the vtable for the base class; but in the 2213 presence of optimization, this initialization may be optimized 2214 away, so we tell finish_vtable_vardecl that we want the debugging 2215 information anyway. */ 2216 2217static tree 2218dfs_debug_mark (tree binfo, void * /*data*/) 2219{ 2220 tree t = BINFO_TYPE (binfo); 2221 2222 if (CLASSTYPE_DEBUG_REQUESTED (t)) 2223 return dfs_skip_bases; 2224 2225 CLASSTYPE_DEBUG_REQUESTED (t) = 1; 2226 2227 return NULL_TREE; 2228} 2229 2230/* Write out the debugging information for TYPE, whose vtable is being 2231 emitted. Also walk through our bases and note that we want to 2232 write out information for them. This avoids the problem of not 2233 writing any debug info for intermediate basetypes whose 2234 constructors, and thus the references to their vtables, and thus 2235 the vtables themselves, were optimized away. */ 2236 2237void 2238note_debug_info_needed (tree type) 2239{ 2240 if (TYPE_DECL_SUPPRESS_DEBUG (TYPE_NAME (type))) 2241 { 2242 TYPE_DECL_SUPPRESS_DEBUG (TYPE_NAME (type)) = 0; 2243 rest_of_type_compilation (type, namespace_bindings_p ()); 2244 } 2245 2246 dfs_walk_all (TYPE_BINFO (type), dfs_debug_mark, NULL, 0); 2247} 2248 2249/* Helper for lookup_conversions_r. TO_TYPE is the type converted to 2250 by a conversion op in base BINFO. VIRTUAL_DEPTH is nonzero if 2251 BINFO is morally virtual, and VIRTUALNESS is nonzero if virtual 2252 bases have been encountered already in the tree walk. PARENT_CONVS 2253 is the list of lists of conversion functions that could hide CONV 2254 and OTHER_CONVS is the list of lists of conversion functions that 2255 could hide or be hidden by CONV, should virtualness be involved in 2256 the hierarchy. Merely checking the conversion op's name is not 2257 enough because two conversion operators to the same type can have 2258 different names. Return nonzero if we are visible. */ 2259 2260static int 2261check_hidden_convs (tree binfo, int virtual_depth, int virtualness, 2262 tree to_type, tree parent_convs, tree other_convs) 2263{ 2264 tree level, probe; 2265 2266 /* See if we are hidden by a parent conversion. */ 2267 for (level = parent_convs; level; level = TREE_CHAIN (level)) 2268 for (probe = TREE_VALUE (level); probe; probe = TREE_CHAIN (probe)) 2269 if (same_type_p (to_type, TREE_TYPE (probe))) 2270 return 0; 2271 2272 if (virtual_depth || virtualness) 2273 { 2274 /* In a virtual hierarchy, we could be hidden, or could hide a 2275 conversion function on the other_convs list. */ 2276 for (level = other_convs; level; level = TREE_CHAIN (level)) 2277 { 2278 int we_hide_them; 2279 int they_hide_us; 2280 tree *prev, other; 2281 2282 if (!(virtual_depth || TREE_STATIC (level))) 2283 /* Neither is morally virtual, so cannot hide each other. */ 2284 continue; 2285 2286 if (!TREE_VALUE (level)) 2287 /* They evaporated away already. */ 2288 continue; 2289 2290 they_hide_us = (virtual_depth 2291 && original_binfo (binfo, TREE_PURPOSE (level))); 2292 we_hide_them = (!they_hide_us && TREE_STATIC (level) 2293 && original_binfo (TREE_PURPOSE (level), binfo)); 2294 2295 if (!(we_hide_them || they_hide_us)) 2296 /* Neither is within the other, so no hiding can occur. */ 2297 continue; 2298 2299 for (prev = &TREE_VALUE (level), other = *prev; other;) 2300 { 2301 if (same_type_p (to_type, TREE_TYPE (other))) 2302 { 2303 if (they_hide_us) 2304 /* We are hidden. */ 2305 return 0; 2306 2307 if (we_hide_them) 2308 { 2309 /* We hide the other one. */ 2310 other = TREE_CHAIN (other); 2311 *prev = other; 2312 continue; 2313 } 2314 } 2315 prev = &TREE_CHAIN (other); 2316 other = *prev; 2317 } 2318 } 2319 } 2320 return 1; 2321} 2322 2323/* Helper for lookup_conversions_r. PARENT_CONVS is a list of lists 2324 of conversion functions, the first slot will be for the current 2325 binfo, if MY_CONVS is non-NULL. CHILD_CONVS is the list of lists 2326 of conversion functions from children of the current binfo, 2327 concatenated with conversions from elsewhere in the hierarchy -- 2328 that list begins with OTHER_CONVS. Return a single list of lists 2329 containing only conversions from the current binfo and its 2330 children. */ 2331 2332static tree 2333split_conversions (tree my_convs, tree parent_convs, 2334 tree child_convs, tree other_convs) 2335{ 2336 tree t; 2337 tree prev; 2338 2339 /* Remove the original other_convs portion from child_convs. */ 2340 for (prev = NULL, t = child_convs; 2341 t != other_convs; prev = t, t = TREE_CHAIN (t)) 2342 continue; 2343 2344 if (prev) 2345 TREE_CHAIN (prev) = NULL_TREE; 2346 else 2347 child_convs = NULL_TREE; 2348 2349 /* Attach the child convs to any we had at this level. */ 2350 if (my_convs) 2351 { 2352 my_convs = parent_convs; 2353 TREE_CHAIN (my_convs) = child_convs; 2354 } 2355 else 2356 my_convs = child_convs; 2357 2358 return my_convs; 2359} 2360 2361/* Worker for lookup_conversions. Lookup conversion functions in 2362 BINFO and its children. VIRTUAL_DEPTH is nonzero, if BINFO is in a 2363 morally virtual base, and VIRTUALNESS is nonzero, if we've 2364 encountered virtual bases already in the tree walk. PARENT_CONVS 2365 is a list of conversions within parent binfos. OTHER_CONVS are 2366 conversions found elsewhere in the tree. Return the conversions 2367 found within this portion of the graph in CONVS. Return nonzero if 2368 we encountered virtualness. We keep template and non-template 2369 conversions separate, to avoid unnecessary type comparisons. 2370 2371 The located conversion functions are held in lists of lists. The 2372 TREE_VALUE of the outer list is the list of conversion functions 2373 found in a particular binfo. The TREE_PURPOSE of both the outer 2374 and inner lists is the binfo at which those conversions were 2375 found. TREE_STATIC is set for those lists within of morally 2376 virtual binfos. The TREE_VALUE of the inner list is the conversion 2377 function or overload itself. The TREE_TYPE of each inner list node 2378 is the converted-to type. */ 2379 2380static int 2381lookup_conversions_r (tree binfo, int virtual_depth, int virtualness, 2382 tree parent_convs, tree other_convs, tree *convs) 2383{ 2384 int my_virtualness = 0; 2385 tree my_convs = NULL_TREE; 2386 tree child_convs = NULL_TREE; 2387 2388 /* If we have no conversion operators, then don't look. */ 2389 if (!TYPE_HAS_CONVERSION (BINFO_TYPE (binfo))) 2390 { 2391 *convs = NULL_TREE; 2392 2393 return 0; 2394 } 2395 2396 if (BINFO_VIRTUAL_P (binfo)) 2397 virtual_depth++; 2398 2399 /* First, locate the unhidden ones at this level. */ 2400 if (tree conv = get_class_binding (BINFO_TYPE (binfo), conv_op_identifier)) 2401 for (ovl_iterator iter (conv); iter; ++iter) 2402 { 2403 tree fn = *iter; 2404 tree type = DECL_CONV_FN_TYPE (fn); 2405 2406 if (TREE_CODE (fn) != TEMPLATE_DECL && type_uses_auto (type)) 2407 { 2408 mark_used (fn); 2409 type = DECL_CONV_FN_TYPE (fn); 2410 } 2411 2412 if (check_hidden_convs (binfo, virtual_depth, virtualness, 2413 type, parent_convs, other_convs)) 2414 { 2415 my_convs = tree_cons (binfo, fn, my_convs); 2416 TREE_TYPE (my_convs) = type; 2417 if (virtual_depth) 2418 { 2419 TREE_STATIC (my_convs) = 1; 2420 my_virtualness = 1; 2421 } 2422 } 2423 } 2424 2425 if (my_convs) 2426 { 2427 parent_convs = tree_cons (binfo, my_convs, parent_convs); 2428 if (virtual_depth) 2429 TREE_STATIC (parent_convs) = 1; 2430 } 2431 2432 child_convs = other_convs; 2433 2434 /* Now iterate over each base, looking for more conversions. */ 2435 unsigned i; 2436 tree base_binfo; 2437 for (i = 0; BINFO_BASE_ITERATE (binfo, i, base_binfo); i++) 2438 { 2439 tree base_convs; 2440 unsigned base_virtualness; 2441 2442 base_virtualness = lookup_conversions_r (base_binfo, 2443 virtual_depth, virtualness, 2444 parent_convs, child_convs, 2445 &base_convs); 2446 if (base_virtualness) 2447 my_virtualness = virtualness = 1; 2448 child_convs = chainon (base_convs, child_convs); 2449 } 2450 2451 *convs = split_conversions (my_convs, parent_convs, 2452 child_convs, other_convs); 2453 2454 return my_virtualness; 2455} 2456 2457/* Return a TREE_LIST containing all the non-hidden user-defined 2458 conversion functions for TYPE (and its base-classes). The 2459 TREE_VALUE of each node is the FUNCTION_DECL of the conversion 2460 function. The TREE_PURPOSE is the BINFO from which the conversion 2461 functions in this node were selected. This function is effectively 2462 performing a set of member lookups as lookup_fnfield does, but 2463 using the type being converted to as the unique key, rather than the 2464 field name. */ 2465 2466tree 2467lookup_conversions (tree type) 2468{ 2469 tree convs; 2470 2471 complete_type (type); 2472 if (!CLASS_TYPE_P (type) || !TYPE_BINFO (type)) 2473 return NULL_TREE; 2474 2475 lookup_conversions_r (TYPE_BINFO (type), 0, 0, NULL_TREE, NULL_TREE, &convs); 2476 2477 tree list = NULL_TREE; 2478 2479 /* Flatten the list-of-lists */ 2480 for (; convs; convs = TREE_CHAIN (convs)) 2481 { 2482 tree probe, next; 2483 2484 for (probe = TREE_VALUE (convs); probe; probe = next) 2485 { 2486 next = TREE_CHAIN (probe); 2487 2488 TREE_CHAIN (probe) = list; 2489 list = probe; 2490 } 2491 } 2492 2493 return list; 2494} 2495 2496/* Returns the binfo of the first direct or indirect virtual base derived 2497 from BINFO, or NULL if binfo is not via virtual. */ 2498 2499tree 2500binfo_from_vbase (tree binfo) 2501{ 2502 for (; binfo; binfo = BINFO_INHERITANCE_CHAIN (binfo)) 2503 { 2504 if (BINFO_VIRTUAL_P (binfo)) 2505 return binfo; 2506 } 2507 return NULL_TREE; 2508} 2509 2510/* Returns the binfo of the first direct or indirect virtual base derived 2511 from BINFO up to the TREE_TYPE, LIMIT, or NULL if binfo is not 2512 via virtual. */ 2513 2514tree 2515binfo_via_virtual (tree binfo, tree limit) 2516{ 2517 if (limit && !CLASSTYPE_VBASECLASSES (limit)) 2518 /* LIMIT has no virtual bases, so BINFO cannot be via one. */ 2519 return NULL_TREE; 2520 2521 for (; binfo && !SAME_BINFO_TYPE_P (BINFO_TYPE (binfo), limit); 2522 binfo = BINFO_INHERITANCE_CHAIN (binfo)) 2523 { 2524 if (BINFO_VIRTUAL_P (binfo)) 2525 return binfo; 2526 } 2527 return NULL_TREE; 2528} 2529 2530/* BINFO is for a base class in some hierarchy. Return true iff it is a 2531 direct base. */ 2532 2533bool 2534binfo_direct_p (tree binfo) 2535{ 2536 tree d_binfo = BINFO_INHERITANCE_CHAIN (binfo); 2537 if (BINFO_INHERITANCE_CHAIN (d_binfo)) 2538 /* A second inheritance chain means indirect. */ 2539 return false; 2540 if (!BINFO_VIRTUAL_P (binfo)) 2541 /* Non-virtual, so only one inheritance chain means direct. */ 2542 return true; 2543 /* A virtual base looks like a direct base, so we need to look through the 2544 direct bases to see if it's there. */ 2545 tree b_binfo; 2546 for (int i = 0; BINFO_BASE_ITERATE (d_binfo, i, b_binfo); ++i) 2547 if (b_binfo == binfo) 2548 return true; 2549 return false; 2550} 2551 2552/* BINFO is a base binfo in the complete type BINFO_TYPE (HERE). 2553 Find the equivalent binfo within whatever graph HERE is located. 2554 This is the inverse of original_binfo. */ 2555 2556tree 2557copied_binfo (tree binfo, tree here) 2558{ 2559 tree result = NULL_TREE; 2560 2561 if (BINFO_VIRTUAL_P (binfo)) 2562 { 2563 tree t; 2564 2565 for (t = here; BINFO_INHERITANCE_CHAIN (t); 2566 t = BINFO_INHERITANCE_CHAIN (t)) 2567 continue; 2568 2569 result = binfo_for_vbase (BINFO_TYPE (binfo), BINFO_TYPE (t)); 2570 } 2571 else if (BINFO_INHERITANCE_CHAIN (binfo)) 2572 { 2573 tree cbinfo; 2574 tree base_binfo; 2575 int ix; 2576 2577 cbinfo = copied_binfo (BINFO_INHERITANCE_CHAIN (binfo), here); 2578 for (ix = 0; BINFO_BASE_ITERATE (cbinfo, ix, base_binfo); ix++) 2579 if (SAME_BINFO_TYPE_P (BINFO_TYPE (base_binfo), BINFO_TYPE (binfo))) 2580 { 2581 result = base_binfo; 2582 break; 2583 } 2584 } 2585 else 2586 { 2587 gcc_assert (SAME_BINFO_TYPE_P (BINFO_TYPE (here), BINFO_TYPE (binfo))); 2588 result = here; 2589 } 2590 2591 gcc_assert (result); 2592 return result; 2593} 2594 2595tree 2596binfo_for_vbase (tree base, tree t) 2597{ 2598 unsigned ix; 2599 tree binfo; 2600 vec<tree, va_gc> *vbases; 2601 2602 for (vbases = CLASSTYPE_VBASECLASSES (t), ix = 0; 2603 vec_safe_iterate (vbases, ix, &binfo); ix++) 2604 if (SAME_BINFO_TYPE_P (BINFO_TYPE (binfo), base)) 2605 return binfo; 2606 return NULL; 2607} 2608 2609/* BINFO is some base binfo of HERE, within some other 2610 hierarchy. Return the equivalent binfo, but in the hierarchy 2611 dominated by HERE. This is the inverse of copied_binfo. If BINFO 2612 is not a base binfo of HERE, returns NULL_TREE. */ 2613 2614tree 2615original_binfo (tree binfo, tree here) 2616{ 2617 tree result = NULL; 2618 2619 if (SAME_BINFO_TYPE_P (BINFO_TYPE (binfo), BINFO_TYPE (here))) 2620 result = here; 2621 else if (BINFO_VIRTUAL_P (binfo)) 2622 result = (CLASSTYPE_VBASECLASSES (BINFO_TYPE (here)) 2623 ? binfo_for_vbase (BINFO_TYPE (binfo), BINFO_TYPE (here)) 2624 : NULL_TREE); 2625 else if (BINFO_INHERITANCE_CHAIN (binfo)) 2626 { 2627 tree base_binfos; 2628 2629 base_binfos = original_binfo (BINFO_INHERITANCE_CHAIN (binfo), here); 2630 if (base_binfos) 2631 { 2632 int ix; 2633 tree base_binfo; 2634 2635 for (ix = 0; (base_binfo = BINFO_BASE_BINFO (base_binfos, ix)); ix++) 2636 if (SAME_BINFO_TYPE_P (BINFO_TYPE (base_binfo), 2637 BINFO_TYPE (binfo))) 2638 { 2639 result = base_binfo; 2640 break; 2641 } 2642 } 2643 } 2644 2645 return result; 2646} 2647 2648/* True iff TYPE has any dependent bases (and therefore we can't say 2649 definitively that another class is not a base of an instantiation of 2650 TYPE). */ 2651 2652bool 2653any_dependent_bases_p (tree type) 2654{ 2655 if (!type || !CLASS_TYPE_P (type) || !uses_template_parms (type)) 2656 return false; 2657 2658 /* If we haven't set TYPE_BINFO yet, we don't know anything about the bases. 2659 Return false because in this situation we aren't actually looking up names 2660 in the scope of the class, so it doesn't matter whether it has dependent 2661 bases. */ 2662 if (!TYPE_BINFO (type)) 2663 return false; 2664 2665 unsigned i; 2666 tree base_binfo; 2667 FOR_EACH_VEC_SAFE_ELT (BINFO_BASE_BINFOS (TYPE_BINFO (type)), i, base_binfo) 2668 if (BINFO_DEPENDENT_BASE_P (base_binfo)) 2669 return true; 2670 2671 return false; 2672} 2673