1 /* Breadth-first and depth-first routines for
2 searching multiple-inheritance lattice for GNU C++.
3 Copyright (C) 1987, 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
4 1999, 2000, 2002, 2003 Free Software Foundation, Inc.
5 Contributed by Michael Tiemann (tiemann@cygnus.com)
7 This file is part of GCC.
9 GCC is free software; you can redistribute it and/or modify
10 it under the terms of the GNU General Public License as published by
11 the Free Software Foundation; either version 2, or (at your option)
14 GCC is distributed in the hope that it will be useful,
15 but WITHOUT ANY WARRANTY; without even the implied warranty of
16 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 GNU General Public License for more details.
19 You should have received a copy of the GNU General Public License
20 along with GCC; see the file COPYING. If not, write to
21 the Free Software Foundation, 59 Temple Place - Suite 330,
22 Boston, MA 02111-1307, USA. */
24 /* High-level class interface. */
28 #include "coretypes.h"
39 /* Obstack used for remembering decision points of breadth-first. */
41 static struct obstack search_obstack;
43 /* Methods for pushing and popping objects to and from obstacks. */
46 push_stack_level (obstack, tp, size)
47 struct obstack *obstack;
48 char *tp; /* Sony NewsOS 5.0 compiler doesn't like void * here. */
51 struct stack_level *stack;
52 obstack_grow (obstack, tp, size);
53 stack = (struct stack_level *) ((char*)obstack_next_free (obstack) - size);
54 obstack_finish (obstack);
55 stack->obstack = obstack;
56 stack->first = (tree *) obstack_base (obstack);
57 stack->limit = obstack_room (obstack) / sizeof (tree *);
62 pop_stack_level (stack)
63 struct stack_level *stack;
65 struct stack_level *tem = stack;
66 struct obstack *obstack = tem->obstack;
68 obstack_free (obstack, tem);
72 #define search_level stack_level
73 static struct search_level *search_stack;
77 /* The class dominating the hierarchy. */
79 /* A pointer to a complete object of the indicated TYPE. */
84 static tree dfs_check_overlap (tree, void *);
85 static tree dfs_no_overlap_yet (tree, int, void *);
86 static base_kind lookup_base_r (tree, tree, base_access,
87 bool, bool, bool, tree *);
88 static int dynamic_cast_base_recurse (tree, tree, bool, tree *);
89 static tree marked_pushdecls_p (tree, int, void *);
90 static tree unmarked_pushdecls_p (tree, int, void *);
91 static tree dfs_debug_unmarkedp (tree, int, void *);
92 static tree dfs_debug_mark (tree, void *);
93 static tree dfs_push_type_decls (tree, void *);
94 static tree dfs_push_decls (tree, void *);
95 static tree dfs_unuse_fields (tree, void *);
96 static tree add_conversions (tree, void *);
97 static int look_for_overrides_r (tree, tree);
98 static struct search_level *push_search_level (struct stack_level *,
100 static struct search_level *pop_search_level (struct stack_level *);
101 static tree bfs_walk (tree, tree (*) (tree, void *),
102 tree (*) (tree, int, void *), void *);
103 static tree lookup_field_queue_p (tree, int, void *);
104 static int shared_member_p (tree);
105 static tree lookup_field_r (tree, void *);
106 static tree dfs_accessible_queue_p (tree, int, void *);
107 static tree dfs_accessible_p (tree, void *);
108 static tree dfs_access_in_type (tree, void *);
109 static access_kind access_in_type (tree, tree);
110 static int protected_accessible_p (tree, tree, tree);
111 static int friend_accessible_p (tree, tree, tree);
112 static void setup_class_bindings (tree, int);
113 static int template_self_reference_p (tree, tree);
114 static tree dfs_get_pure_virtuals (tree, void *);
116 /* Allocate a level of searching. */
118 static struct search_level *
119 push_search_level (struct stack_level *stack, struct obstack *obstack)
121 struct search_level tem;
124 return push_stack_level (obstack, (char *)&tem, sizeof (tem));
127 /* Discard a level of search allocation. */
129 static struct search_level *
130 pop_search_level (struct stack_level *obstack)
132 register struct search_level *stack = pop_stack_level (obstack);
137 /* Variables for gathering statistics. */
138 #ifdef GATHER_STATISTICS
139 static int n_fields_searched;
140 static int n_calls_lookup_field, n_calls_lookup_field_1;
141 static int n_calls_lookup_fnfields, n_calls_lookup_fnfields_1;
142 static int n_calls_get_base_type;
143 static int n_outer_fields_searched;
144 static int n_contexts_saved;
145 #endif /* GATHER_STATISTICS */
148 /* Worker for lookup_base. BINFO is the binfo we are searching at,
149 BASE is the RECORD_TYPE we are searching for. ACCESS is the
150 required access checks. WITHIN_CURRENT_SCOPE, IS_NON_PUBLIC and
151 IS_VIRTUAL indicate how BINFO was reached from the start of the
152 search. WITHIN_CURRENT_SCOPE is true if we met the current scope,
153 or friend thereof (this allows us to determine whether a protected
154 base is accessible or not). IS_NON_PUBLIC indicates whether BINFO
155 is accessible and IS_VIRTUAL indicates if it is morally virtual.
157 If BINFO is of the required type, then *BINFO_PTR is examined to
158 compare with any other instance of BASE we might have already
159 discovered. *BINFO_PTR is initialized and a base_kind return value
160 indicates what kind of base was located.
162 Otherwise BINFO's bases are searched. */
165 lookup_base_r (tree binfo, tree base, base_access access,
166 bool within_current_scope,
167 bool is_non_public, /* inside a non-public part */
168 bool is_virtual, /* inside a virtual part */
172 tree bases, accesses;
173 base_kind found = bk_not_base;
175 if (access == ba_check
176 && !within_current_scope
177 && is_friend (BINFO_TYPE (binfo), current_scope ()))
179 /* Do not clear is_non_public here. If A is a private base of B, A
180 is not allowed to convert a B* to an A*. */
181 within_current_scope = 1;
184 if (same_type_p (BINFO_TYPE (binfo), base))
186 /* We have found a base. Check against what we have found
188 found = bk_same_type;
190 found = bk_via_virtual;
192 found = bk_inaccessible;
196 else if (binfo != *binfo_ptr)
198 if (access != ba_any)
200 else if (!is_virtual)
201 /* Prefer a non-virtual base. */
209 bases = BINFO_BASETYPES (binfo);
210 accesses = BINFO_BASEACCESSES (binfo);
214 for (i = TREE_VEC_LENGTH (bases); i--;)
216 tree base_binfo = TREE_VEC_ELT (bases, i);
217 tree base_access = TREE_VEC_ELT (accesses, i);
219 int this_non_public = is_non_public;
220 int this_virtual = is_virtual;
223 if (access <= ba_ignore)
225 else if (base_access == access_public_node)
227 else if (access == ba_not_special)
229 else if (base_access == access_protected_node && within_current_scope)
231 else if (is_friend (BINFO_TYPE (binfo), current_scope ()))
236 if (TREE_VIA_VIRTUAL (base_binfo))
239 bk = lookup_base_r (base_binfo, base,
240 access, within_current_scope,
241 this_non_public, this_virtual,
247 if (access != ba_any)
252 case bk_inaccessible:
253 if (found == bk_not_base)
255 my_friendly_assert (found == bk_via_virtual
256 || found == bk_inaccessible, 20010723);
264 my_friendly_assert (found == bk_not_base, 20010723);
269 if (found != bk_ambig)
280 /* Lookup BASE in the hierarchy dominated by T. Do access checking as
281 ACCESS specifies. Return the binfo we discover. If KIND_PTR is
282 non-NULL, fill with information about what kind of base we
285 If the base is inaccessible, or ambiguous, and the ba_quiet bit is
286 not set in ACCESS, then an error is issued and error_mark_node is
287 returned. If the ba_quiet bit is set, then no error is issued and
288 NULL_TREE is returned. */
291 lookup_base (tree t, tree base, base_access access, base_kind *kind_ptr)
293 tree binfo = NULL; /* The binfo we've found so far. */
297 if (t == error_mark_node || base == error_mark_node)
300 *kind_ptr = bk_not_base;
301 return error_mark_node;
303 my_friendly_assert (TYPE_P (base), 20011127);
311 t_binfo = TYPE_BINFO (t);
313 /* Ensure that the types are instantiated. */
314 t = complete_type (TYPE_MAIN_VARIANT (t));
315 base = complete_type (TYPE_MAIN_VARIANT (base));
317 bk = lookup_base_r (t_binfo, base, access & ~ba_quiet,
322 case bk_inaccessible:
324 if (!(access & ba_quiet))
326 error ("`%T' is an inaccessible base of `%T'", base, t);
327 binfo = error_mark_node;
331 if (access != ba_any)
334 if (!(access & ba_quiet))
336 error ("`%T' is an ambiguous base of `%T'", base, t);
337 binfo = error_mark_node;
350 /* Worker function for get_dynamic_cast_base_type. */
353 dynamic_cast_base_recurse (tree subtype, tree binfo, bool is_via_virtual,
356 tree binfos, accesses;
360 if (BINFO_TYPE (binfo) == subtype)
366 *offset_ptr = BINFO_OFFSET (binfo);
371 binfos = BINFO_BASETYPES (binfo);
372 accesses = BINFO_BASEACCESSES (binfo);
373 n_baselinks = binfos ? TREE_VEC_LENGTH (binfos) : 0;
374 for (i = 0; i < n_baselinks; i++)
376 tree base_binfo = TREE_VEC_ELT (binfos, i);
377 tree base_access = TREE_VEC_ELT (accesses, i);
380 if (base_access != access_public_node)
382 rval = dynamic_cast_base_recurse
383 (subtype, base_binfo,
384 is_via_virtual || TREE_VIA_VIRTUAL (base_binfo), offset_ptr);
388 worst = worst >= 0 ? -3 : worst;
391 else if (rval == -3 && worst != -1)
397 /* The dynamic cast runtime needs a hint about how the static SUBTYPE type
398 started from is related to the required TARGET type, in order to optimize
399 the inheritance graph search. This information is independent of the
400 current context, and ignores private paths, hence get_base_distance is
401 inappropriate. Return a TREE specifying the base offset, BOFF.
402 BOFF >= 0, there is only one public non-virtual SUBTYPE base at offset BOFF,
403 and there are no public virtual SUBTYPE bases.
404 BOFF == -1, SUBTYPE occurs as multiple public virtual or non-virtual bases.
405 BOFF == -2, SUBTYPE is not a public base.
406 BOFF == -3, SUBTYPE occurs as multiple public non-virtual bases. */
409 get_dynamic_cast_base_type (tree subtype, tree target)
411 tree offset = NULL_TREE;
412 int boff = dynamic_cast_base_recurse (subtype, TYPE_BINFO (target),
417 offset = build_int_2 (boff, -1);
418 TREE_TYPE (offset) = ssizetype;
422 /* Search for a member with name NAME in a multiple inheritance
423 lattice specified by TYPE. If it does not exist, return NULL_TREE.
424 If the member is ambiguously referenced, return `error_mark_node'.
425 Otherwise, return a DECL with the indicated name. If WANT_TYPE is
426 true, type declarations are preferred. */
428 /* Do a 1-level search for NAME as a member of TYPE. The caller must
429 figure out whether it can access this field. (Since it is only one
430 level, this is reasonable.) */
433 lookup_field_1 (tree type, tree name, bool want_type)
437 if (TREE_CODE (type) == TEMPLATE_TYPE_PARM
438 || TREE_CODE (type) == BOUND_TEMPLATE_TEMPLATE_PARM
439 || TREE_CODE (type) == TYPENAME_TYPE)
440 /* The TYPE_FIELDS of a TEMPLATE_TYPE_PARM and
441 BOUND_TEMPLATE_TEMPLATE_PARM are not fields at all;
442 instead TYPE_FIELDS is the TEMPLATE_PARM_INDEX. (Miraculously,
443 the code often worked even when we treated the index as a list
445 The TYPE_FIELDS of TYPENAME_TYPE is its TYPENAME_TYPE_FULLNAME. */
449 && DECL_LANG_SPECIFIC (TYPE_NAME (type))
450 && DECL_SORTED_FIELDS (TYPE_NAME (type)))
452 tree *fields = &TREE_VEC_ELT (DECL_SORTED_FIELDS (TYPE_NAME (type)), 0);
453 int lo = 0, hi = TREE_VEC_LENGTH (DECL_SORTED_FIELDS (TYPE_NAME (type)));
460 #ifdef GATHER_STATISTICS
462 #endif /* GATHER_STATISTICS */
464 if (DECL_NAME (fields[i]) > name)
466 else if (DECL_NAME (fields[i]) < name)
472 /* We might have a nested class and a field with the
473 same name; we sorted them appropriately via
474 field_decl_cmp, so just look for the first or last
475 field with this name. */
480 while (i >= lo && DECL_NAME (fields[i]) == name);
481 if (TREE_CODE (field) != TYPE_DECL
482 && !DECL_CLASS_TEMPLATE_P (field))
489 while (i < hi && DECL_NAME (fields[i]) == name);
497 field = TYPE_FIELDS (type);
499 #ifdef GATHER_STATISTICS
500 n_calls_lookup_field_1++;
501 #endif /* GATHER_STATISTICS */
502 for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
504 #ifdef GATHER_STATISTICS
506 #endif /* GATHER_STATISTICS */
507 my_friendly_assert (DECL_P (field), 0);
508 if (DECL_NAME (field) == NULL_TREE
509 && ANON_AGGR_TYPE_P (TREE_TYPE (field)))
511 tree temp = lookup_field_1 (TREE_TYPE (field), name, want_type);
515 if (TREE_CODE (field) == USING_DECL)
516 /* For now, we're just treating member using declarations as
517 old ARM-style access declarations. Thus, there's no reason
518 to return a USING_DECL, and the rest of the compiler can't
519 handle it. Once the class is defined, these are purged
520 from TYPE_FIELDS anyhow; see handle_using_decl. */
523 if (DECL_NAME (field) == name
525 || TREE_CODE (field) == TYPE_DECL
526 || DECL_CLASS_TEMPLATE_P (field)))
530 if (name == vptr_identifier)
532 /* Give the user what s/he thinks s/he wants. */
533 if (TYPE_POLYMORPHIC_P (type))
534 return TYPE_VFIELD (type);
539 /* There are a number of cases we need to be aware of here:
540 current_class_type current_function_decl
547 Those last two make life interesting. If we're in a function which is
548 itself inside a class, we need decls to go into the fn's decls (our
549 second case below). But if we're in a class and the class itself is
550 inside a function, we need decls to go into the decls for the class. To
551 achieve this last goal, we must see if, when both current_class_ptr and
552 current_function_decl are set, the class was declared inside that
553 function. If so, we know to put the decls into the class's scope. */
558 if (current_function_decl == NULL_TREE)
559 return current_class_type;
560 if (current_class_type == NULL_TREE)
561 return current_function_decl;
562 if ((DECL_FUNCTION_MEMBER_P (current_function_decl)
563 && same_type_p (DECL_CONTEXT (current_function_decl),
565 || (DECL_FRIEND_CONTEXT (current_function_decl)
566 && same_type_p (DECL_FRIEND_CONTEXT (current_function_decl),
567 current_class_type)))
568 return current_function_decl;
570 return current_class_type;
573 /* Returns nonzero if we are currently in a function scope. Note
574 that this function returns zero if we are within a local class, but
575 not within a member function body of the local class. */
578 at_function_scope_p ()
580 tree cs = current_scope ();
581 return cs && TREE_CODE (cs) == FUNCTION_DECL;
584 /* Returns true if the innermost active scope is a class scope. */
589 tree cs = current_scope ();
590 return cs && TYPE_P (cs);
593 /* Return the scope of DECL, as appropriate when doing name-lookup. */
596 context_for_name_lookup (tree decl)
600 For the purposes of name lookup, after the anonymous union
601 definition, the members of the anonymous union are considered to
602 have been defined in the scope in which the anonymous union is
604 tree context = DECL_CONTEXT (decl);
606 while (context && TYPE_P (context) && ANON_AGGR_TYPE_P (context))
607 context = TYPE_CONTEXT (context);
609 context = global_namespace;
614 /* The accessibility routines use BINFO_ACCESS for scratch space
615 during the computation of the accssibility of some declaration. */
617 #define BINFO_ACCESS(NODE) \
618 ((access_kind) ((TREE_PUBLIC (NODE) << 1) | TREE_PRIVATE (NODE)))
620 /* Set the access associated with NODE to ACCESS. */
622 #define SET_BINFO_ACCESS(NODE, ACCESS) \
623 ((TREE_PUBLIC (NODE) = ((ACCESS) & 2) != 0), \
624 (TREE_PRIVATE (NODE) = ((ACCESS) & 1) != 0))
626 /* Called from access_in_type via dfs_walk. Calculate the access to
627 DATA (which is really a DECL) in BINFO. */
630 dfs_access_in_type (tree binfo, void *data)
632 tree decl = (tree) data;
633 tree type = BINFO_TYPE (binfo);
634 access_kind access = ak_none;
636 if (context_for_name_lookup (decl) == type)
638 /* If we have desceneded to the scope of DECL, just note the
639 appropriate access. */
640 if (TREE_PRIVATE (decl))
642 else if (TREE_PROTECTED (decl))
643 access = ak_protected;
649 /* First, check for an access-declaration that gives us more
650 access to the DECL. The CONST_DECL for an enumeration
651 constant will not have DECL_LANG_SPECIFIC, and thus no
653 if (DECL_LANG_SPECIFIC (decl) && !DECL_DISCRIMINATOR_P (decl))
655 tree decl_access = purpose_member (type, DECL_ACCESS (decl));
659 decl_access = TREE_VALUE (decl_access);
661 if (decl_access == access_public_node)
663 else if (decl_access == access_protected_node)
664 access = ak_protected;
665 else if (decl_access == access_private_node)
668 my_friendly_assert (false, 20030217);
676 tree binfos, accesses;
678 /* Otherwise, scan our baseclasses, and pick the most favorable
680 binfos = BINFO_BASETYPES (binfo);
681 accesses = BINFO_BASEACCESSES (binfo);
682 n_baselinks = binfos ? TREE_VEC_LENGTH (binfos) : 0;
683 for (i = 0; i < n_baselinks; ++i)
685 tree base_binfo = TREE_VEC_ELT (binfos, i);
686 tree base_access = TREE_VEC_ELT (accesses, i);
687 access_kind base_access_now = BINFO_ACCESS (base_binfo);
689 if (base_access_now == ak_none || base_access_now == ak_private)
690 /* If it was not accessible in the base, or only
691 accessible as a private member, we can't access it
693 base_access_now = ak_none;
694 else if (base_access == access_protected_node)
695 /* Public and protected members in the base become
697 base_access_now = ak_protected;
698 else if (base_access == access_private_node)
699 /* Public and protected members in the base become
701 base_access_now = ak_private;
703 /* See if the new access, via this base, gives more
704 access than our previous best access. */
705 if (base_access_now != ak_none
706 && (access == ak_none || base_access_now < access))
708 access = base_access_now;
710 /* If the new access is public, we can't do better. */
711 if (access == ak_public)
718 /* Note the access to DECL in TYPE. */
719 SET_BINFO_ACCESS (binfo, access);
721 /* Mark TYPE as visited so that if we reach it again we do not
722 duplicate our efforts here. */
723 BINFO_MARKED (binfo) = 1;
728 /* Return the access to DECL in TYPE. */
731 access_in_type (tree type, tree decl)
733 tree binfo = TYPE_BINFO (type);
735 /* We must take into account
739 If a name can be reached by several paths through a multiple
740 inheritance graph, the access is that of the path that gives
743 The algorithm we use is to make a post-order depth-first traversal
744 of the base-class hierarchy. As we come up the tree, we annotate
745 each node with the most lenient access. */
746 dfs_walk_real (binfo, 0, dfs_access_in_type, unmarkedp, decl);
747 dfs_walk (binfo, dfs_unmark, markedp, 0);
749 return BINFO_ACCESS (binfo);
752 /* Called from dfs_accessible_p via dfs_walk. */
755 dfs_accessible_queue_p (tree derived, int ix, void *data ATTRIBUTE_UNUSED)
757 tree binfo = BINFO_BASETYPE (derived, ix);
759 if (BINFO_MARKED (binfo))
762 /* If this class is inherited via private or protected inheritance,
763 then we can't see it, unless we are a friend of the derived class. */
764 if (BINFO_BASEACCESS (derived, ix) != access_public_node
765 && !is_friend (BINFO_TYPE (derived), current_scope ()))
771 /* Called from dfs_accessible_p via dfs_walk. */
774 dfs_accessible_p (tree binfo, void *data)
776 int protected_ok = data != 0;
779 BINFO_MARKED (binfo) = 1;
780 access = BINFO_ACCESS (binfo);
781 if (access == ak_public || (access == ak_protected && protected_ok))
783 else if (access != ak_none
784 && is_friend (BINFO_TYPE (binfo), current_scope ()))
790 /* Returns nonzero if it is OK to access DECL through an object
791 indiated by BINFO in the context of DERIVED. */
794 protected_accessible_p (tree decl, tree derived, tree binfo)
798 /* We're checking this clause from [class.access.base]
800 m as a member of N is protected, and the reference occurs in a
801 member or friend of class N, or in a member or friend of a
802 class P derived from N, where m as a member of P is private or
805 Here DERIVED is a possible P and DECL is m. accessible_p will
806 iterate over various values of N, but the access to m in DERIVED
809 Note that I believe that the passage above is wrong, and should read
810 "...is private or protected or public"; otherwise you get bizarre results
811 whereby a public using-decl can prevent you from accessing a protected
812 member of a base. (jason 2000/02/28) */
814 /* If DERIVED isn't derived from m's class, then it can't be a P. */
815 if (!DERIVED_FROM_P (context_for_name_lookup (decl), derived))
818 access = access_in_type (derived, decl);
820 /* If m is inaccessible in DERIVED, then it's not a P. */
821 if (access == ak_none)
826 When a friend or a member function of a derived class references
827 a protected nonstatic member of a base class, an access check
828 applies in addition to those described earlier in clause
829 _class.access_) Except when forming a pointer to member
830 (_expr.unary.op_), the access must be through a pointer to,
831 reference to, or object of the derived class itself (or any class
832 derived from that class) (_expr.ref_). If the access is to form
833 a pointer to member, the nested-name-specifier shall name the
834 derived class (or any class derived from that class). */
835 if (DECL_NONSTATIC_MEMBER_P (decl))
837 /* We can tell through what the reference is occurring by
838 chasing BINFO up to the root. */
840 while (BINFO_INHERITANCE_CHAIN (t))
841 t = BINFO_INHERITANCE_CHAIN (t);
843 if (!DERIVED_FROM_P (derived, BINFO_TYPE (t)))
850 /* Returns nonzero if SCOPE is a friend of a type which would be able
851 to access DECL through the object indicated by BINFO. */
854 friend_accessible_p (tree scope, tree decl, tree binfo)
856 tree befriending_classes;
862 if (TREE_CODE (scope) == FUNCTION_DECL
863 || DECL_FUNCTION_TEMPLATE_P (scope))
864 befriending_classes = DECL_BEFRIENDING_CLASSES (scope);
865 else if (TYPE_P (scope))
866 befriending_classes = CLASSTYPE_BEFRIENDING_CLASSES (scope);
870 for (t = befriending_classes; t; t = TREE_CHAIN (t))
871 if (protected_accessible_p (decl, TREE_VALUE (t), binfo))
874 /* Nested classes are implicitly friends of their enclosing types, as
875 per core issue 45 (this is a change from the standard). */
877 for (t = TYPE_CONTEXT (scope); t && TYPE_P (t); t = TYPE_CONTEXT (t))
878 if (protected_accessible_p (decl, t, binfo))
881 if (TREE_CODE (scope) == FUNCTION_DECL
882 || DECL_FUNCTION_TEMPLATE_P (scope))
884 /* Perhaps this SCOPE is a member of a class which is a
886 if (DECL_CLASS_SCOPE_P (decl)
887 && friend_accessible_p (DECL_CONTEXT (scope), decl, binfo))
890 /* Or an instantiation of something which is a friend. */
891 if (DECL_TEMPLATE_INFO (scope))
892 return friend_accessible_p (DECL_TI_TEMPLATE (scope), decl, binfo);
894 else if (CLASSTYPE_TEMPLATE_INFO (scope))
895 return friend_accessible_p (CLASSTYPE_TI_TEMPLATE (scope), decl, binfo);
900 /* DECL is a declaration from a base class of TYPE, which was the
901 class used to name DECL. Return nonzero if, in the current
902 context, DECL is accessible. If TYPE is actually a BINFO node,
903 then we can tell in what context the access is occurring by looking
904 at the most derived class along the path indicated by BINFO. */
907 accessible_p (tree type, tree decl)
912 /* Nonzero if it's OK to access DECL if it has protected
913 accessibility in TYPE. */
914 int protected_ok = 0;
916 /* If this declaration is in a block or namespace scope, there's no
918 if (!TYPE_P (context_for_name_lookup (decl)))
924 type = BINFO_TYPE (type);
927 binfo = TYPE_BINFO (type);
929 /* [class.access.base]
931 A member m is accessible when named in class N if
933 --m as a member of N is public, or
935 --m as a member of N is private, and the reference occurs in a
936 member or friend of class N, or
938 --m as a member of N is protected, and the reference occurs in a
939 member or friend of class N, or in a member or friend of a
940 class P derived from N, where m as a member of P is private or
943 --there exists a base class B of N that is accessible at the point
944 of reference, and m is accessible when named in class B.
946 We walk the base class hierarchy, checking these conditions. */
948 /* Figure out where the reference is occurring. Check to see if
949 DECL is private or protected in this scope, since that will
950 determine whether protected access is allowed. */
951 if (current_class_type)
952 protected_ok = protected_accessible_p (decl, current_class_type, binfo);
954 /* Now, loop through the classes of which we are a friend. */
956 protected_ok = friend_accessible_p (current_scope (), decl, binfo);
958 /* Standardize the binfo that access_in_type will use. We don't
959 need to know what path was chosen from this point onwards. */
960 binfo = TYPE_BINFO (type);
962 /* Compute the accessibility of DECL in the class hierarchy
963 dominated by type. */
964 access_in_type (type, decl);
965 /* Walk the hierarchy again, looking for a base class that allows
967 t = dfs_walk (binfo, dfs_accessible_p,
968 dfs_accessible_queue_p,
969 protected_ok ? &protected_ok : 0);
970 /* Clear any mark bits. Note that we have to walk the whole tree
971 here, since we have aborted the previous walk from some point
973 dfs_walk (binfo, dfs_unmark, 0, 0);
975 return t != NULL_TREE;
978 struct lookup_field_info {
979 /* The type in which we're looking. */
981 /* The name of the field for which we're looking. */
983 /* If non-NULL, the current result of the lookup. */
985 /* The path to RVAL. */
987 /* If non-NULL, the lookup was ambiguous, and this is a list of the
990 /* If nonzero, we are looking for types, not data members. */
992 /* If something went wrong, a message indicating what. */
996 /* Returns nonzero if BINFO is not hidden by the value found by the
997 lookup so far. If BINFO is hidden, then there's no need to look in
998 it. DATA is really a struct lookup_field_info. Called from
999 lookup_field via breadth_first_search. */
1002 lookup_field_queue_p (tree derived, int ix, void *data)
1004 tree binfo = BINFO_BASETYPE (derived, ix);
1005 struct lookup_field_info *lfi = (struct lookup_field_info *) data;
1007 /* Don't look for constructors or destructors in base classes. */
1008 if (IDENTIFIER_CTOR_OR_DTOR_P (lfi->name))
1011 /* If this base class is hidden by the best-known value so far, we
1012 don't need to look. */
1013 if (lfi->rval_binfo && original_binfo (binfo, lfi->rval_binfo))
1016 /* If this is a dependent base, don't look in it. */
1017 if (BINFO_DEPENDENT_BASE_P (binfo))
1023 /* Within the scope of a template class, you can refer to the to the
1024 current specialization with the name of the template itself. For
1027 template <typename T> struct S { S* sp; }
1029 Returns nonzero if DECL is such a declaration in a class TYPE. */
1032 template_self_reference_p (tree type, tree decl)
1034 return (CLASSTYPE_USE_TEMPLATE (type)
1035 && PRIMARY_TEMPLATE_P (CLASSTYPE_TI_TEMPLATE (type))
1036 && TREE_CODE (decl) == TYPE_DECL
1037 && DECL_ARTIFICIAL (decl)
1038 && DECL_NAME (decl) == constructor_name (type));
1042 /* Nonzero for a class member means that it is shared between all objects
1045 [class.member.lookup]:If the resulting set of declarations are not all
1046 from sub-objects of the same type, or the set has a nonstatic member
1047 and includes members from distinct sub-objects, there is an ambiguity
1048 and the program is ill-formed.
1050 This function checks that T contains no nonstatic members. */
1053 shared_member_p (tree t)
1055 if (TREE_CODE (t) == VAR_DECL || TREE_CODE (t) == TYPE_DECL \
1056 || TREE_CODE (t) == CONST_DECL)
1058 if (is_overloaded_fn (t))
1060 for (; t; t = OVL_NEXT (t))
1062 tree fn = OVL_CURRENT (t);
1063 if (DECL_NONSTATIC_MEMBER_FUNCTION_P (fn))
1071 /* DATA is really a struct lookup_field_info. Look for a field with
1072 the name indicated there in BINFO. If this function returns a
1073 non-NULL value it is the result of the lookup. Called from
1074 lookup_field via breadth_first_search. */
1077 lookup_field_r (tree binfo, void *data)
1079 struct lookup_field_info *lfi = (struct lookup_field_info *) data;
1080 tree type = BINFO_TYPE (binfo);
1081 tree nval = NULL_TREE;
1083 /* First, look for a function. There can't be a function and a data
1084 member with the same name, and if there's a function and a type
1085 with the same name, the type is hidden by the function. */
1086 if (!lfi->want_type)
1088 int idx = lookup_fnfields_1 (type, lfi->name);
1090 nval = TREE_VEC_ELT (CLASSTYPE_METHOD_VEC (type), idx);
1094 /* Look for a data member or type. */
1095 nval = lookup_field_1 (type, lfi->name, lfi->want_type);
1097 /* If there is no declaration with the indicated name in this type,
1098 then there's nothing to do. */
1102 /* If we're looking up a type (as with an elaborated type specifier)
1103 we ignore all non-types we find. */
1104 if (lfi->want_type && TREE_CODE (nval) != TYPE_DECL
1105 && !DECL_CLASS_TEMPLATE_P (nval))
1107 if (lfi->name == TYPE_IDENTIFIER (type))
1109 /* If the aggregate has no user defined constructors, we allow
1110 it to have fields with the same name as the enclosing type.
1111 If we are looking for that name, find the corresponding
1113 for (nval = TREE_CHAIN (nval); nval; nval = TREE_CHAIN (nval))
1114 if (DECL_NAME (nval) == lfi->name
1115 && TREE_CODE (nval) == TYPE_DECL)
1120 if (!nval && CLASSTYPE_NESTED_UTDS (type) != NULL)
1122 binding_entry e = binding_table_find (CLASSTYPE_NESTED_UTDS (type),
1125 nval = TYPE_MAIN_DECL (e->type);
1131 /* You must name a template base class with a template-id. */
1132 if (!same_type_p (type, lfi->type)
1133 && template_self_reference_p (type, nval))
1136 /* If the lookup already found a match, and the new value doesn't
1137 hide the old one, we might have an ambiguity. */
1138 if (lfi->rval_binfo && !original_binfo (lfi->rval_binfo, binfo))
1140 if (nval == lfi->rval && shared_member_p (nval))
1141 /* The two things are really the same. */
1143 else if (original_binfo (binfo, lfi->rval_binfo))
1144 /* The previous value hides the new one. */
1148 /* We have a real ambiguity. We keep a chain of all the
1150 if (!lfi->ambiguous && lfi->rval)
1152 /* This is the first time we noticed an ambiguity. Add
1153 what we previously thought was a reasonable candidate
1155 lfi->ambiguous = tree_cons (NULL_TREE, lfi->rval, NULL_TREE);
1156 TREE_TYPE (lfi->ambiguous) = error_mark_node;
1159 /* Add the new value. */
1160 lfi->ambiguous = tree_cons (NULL_TREE, nval, lfi->ambiguous);
1161 TREE_TYPE (lfi->ambiguous) = error_mark_node;
1162 lfi->errstr = "request for member `%D' is ambiguous";
1168 lfi->rval_binfo = binfo;
1174 /* Return a "baselink" which BASELINK_BINFO, BASELINK_ACCESS_BINFO,
1175 BASELINK_FUNCTIONS, and BASELINK_OPTYPE set to BINFO, ACCESS_BINFO,
1176 FUNCTIONS, and OPTYPE respectively. */
1179 build_baselink (tree binfo, tree access_binfo, tree functions, tree optype)
1183 my_friendly_assert (TREE_CODE (functions) == FUNCTION_DECL
1184 || TREE_CODE (functions) == TEMPLATE_DECL
1185 || TREE_CODE (functions) == TEMPLATE_ID_EXPR
1186 || TREE_CODE (functions) == OVERLOAD,
1188 my_friendly_assert (!optype || TYPE_P (optype), 20020730);
1189 my_friendly_assert (TREE_TYPE (functions), 20020805);
1191 baselink = make_node (BASELINK);
1192 TREE_TYPE (baselink) = TREE_TYPE (functions);
1193 BASELINK_BINFO (baselink) = binfo;
1194 BASELINK_ACCESS_BINFO (baselink) = access_binfo;
1195 BASELINK_FUNCTIONS (baselink) = functions;
1196 BASELINK_OPTYPE (baselink) = optype;
1201 /* Look for a member named NAME in an inheritance lattice dominated by
1202 XBASETYPE. If PROTECT is 0 or two, we do not check access. If it
1203 is 1, we enforce accessibility. If PROTECT is zero, then, for an
1204 ambiguous lookup, we return NULL. If PROTECT is 1, we issue error
1205 messages about inaccessible or ambiguous lookup. If PROTECT is 2,
1206 we return a TREE_LIST whose TREE_TYPE is error_mark_node and whose
1207 TREE_VALUEs are the list of ambiguous candidates.
1209 WANT_TYPE is 1 when we should only return TYPE_DECLs.
1211 If nothing can be found return NULL_TREE and do not issue an error. */
1214 lookup_member (tree xbasetype, tree name, int protect, bool want_type)
1216 tree rval, rval_binfo = NULL_TREE;
1217 tree type = NULL_TREE, basetype_path = NULL_TREE;
1218 struct lookup_field_info lfi;
1220 /* rval_binfo is the binfo associated with the found member, note,
1221 this can be set with useful information, even when rval is not
1222 set, because it must deal with ALL members, not just non-function
1223 members. It is used for ambiguity checking and the hidden
1224 checks. Whereas rval is only set if a proper (not hidden)
1225 non-function member is found. */
1227 const char *errstr = 0;
1230 if (TREE_CODE (name) != IDENTIFIER_NODE)
1233 if (xbasetype == current_class_type && TYPE_BEING_DEFINED (xbasetype)
1234 && IDENTIFIER_CLASS_VALUE (name))
1236 tree field = IDENTIFIER_CLASS_VALUE (name);
1237 if (! is_overloaded_fn (field)
1238 && ! (want_type && TREE_CODE (field) != TYPE_DECL))
1239 /* We're in the scope of this class, and the value has already
1240 been looked up. Just return the cached value. */
1244 if (TREE_CODE (xbasetype) == TREE_VEC)
1246 type = BINFO_TYPE (xbasetype);
1247 basetype_path = xbasetype;
1249 else if (IS_AGGR_TYPE_CODE (TREE_CODE (xbasetype)))
1252 basetype_path = TYPE_BINFO (type);
1253 my_friendly_assert (BINFO_INHERITANCE_CHAIN (basetype_path) == NULL_TREE,
1259 complete_type (type);
1261 #ifdef GATHER_STATISTICS
1262 n_calls_lookup_field++;
1263 #endif /* GATHER_STATISTICS */
1265 memset ((PTR) &lfi, 0, sizeof (lfi));
1268 lfi.want_type = want_type;
1269 bfs_walk (basetype_path, &lookup_field_r, &lookup_field_queue_p, &lfi);
1271 rval_binfo = lfi.rval_binfo;
1273 type = BINFO_TYPE (rval_binfo);
1274 errstr = lfi.errstr;
1276 /* If we are not interested in ambiguities, don't report them;
1277 just return NULL_TREE. */
1278 if (!protect && lfi.ambiguous)
1284 return lfi.ambiguous;
1291 In the case of overloaded function names, access control is
1292 applied to the function selected by overloaded resolution. */
1293 if (rval && protect && !is_overloaded_fn (rval))
1294 perform_or_defer_access_check (xbasetype, rval);
1296 if (errstr && protect)
1298 error (errstr, name, type);
1300 print_candidates (lfi.ambiguous);
1301 rval = error_mark_node;
1304 if (rval && is_overloaded_fn (rval))
1305 rval = build_baselink (rval_binfo, basetype_path, rval,
1306 (IDENTIFIER_TYPENAME_P (name)
1307 ? TREE_TYPE (name): NULL_TREE));
1311 /* Like lookup_member, except that if we find a function member we
1312 return NULL_TREE. */
1315 lookup_field (tree xbasetype, tree name, int protect, bool want_type)
1317 tree rval = lookup_member (xbasetype, name, protect, want_type);
1319 /* Ignore functions. */
1320 if (rval && BASELINK_P (rval))
1326 /* Like lookup_member, except that if we find a non-function member we
1327 return NULL_TREE. */
1330 lookup_fnfields (tree xbasetype, tree name, int protect)
1332 tree rval = lookup_member (xbasetype, name, protect, /*want_type=*/false);
1334 /* Ignore non-functions. */
1335 if (rval && !BASELINK_P (rval))
1341 /* TYPE is a class type. Return the index of the fields within
1342 the method vector with name NAME, or -1 is no such field exists. */
1345 lookup_fnfields_1 (tree type, tree name)
1347 tree method_vec = (CLASS_TYPE_P (type)
1348 ? CLASSTYPE_METHOD_VEC (type)
1351 if (method_vec != 0)
1354 register tree *methods = &TREE_VEC_ELT (method_vec, 0);
1355 int len = TREE_VEC_LENGTH (method_vec);
1358 #ifdef GATHER_STATISTICS
1359 n_calls_lookup_fnfields_1++;
1360 #endif /* GATHER_STATISTICS */
1362 /* Constructors are first... */
1363 if (name == ctor_identifier)
1364 return (methods[CLASSTYPE_CONSTRUCTOR_SLOT]
1365 ? CLASSTYPE_CONSTRUCTOR_SLOT : -1);
1366 /* and destructors are second. */
1367 if (name == dtor_identifier)
1368 return (methods[CLASSTYPE_DESTRUCTOR_SLOT]
1369 ? CLASSTYPE_DESTRUCTOR_SLOT : -1);
1371 for (i = CLASSTYPE_FIRST_CONVERSION_SLOT;
1372 i < len && methods[i];
1375 #ifdef GATHER_STATISTICS
1376 n_outer_fields_searched++;
1377 #endif /* GATHER_STATISTICS */
1379 tmp = OVL_CURRENT (methods[i]);
1380 if (DECL_NAME (tmp) == name)
1383 /* If the type is complete and we're past the conversion ops,
1384 switch to binary search. */
1385 if (! DECL_CONV_FN_P (tmp)
1386 && COMPLETE_TYPE_P (type))
1388 int lo = i + 1, hi = len;
1394 #ifdef GATHER_STATISTICS
1395 n_outer_fields_searched++;
1396 #endif /* GATHER_STATISTICS */
1399 /* This slot may be empty; we allocate more slots
1400 than we need. In that case, the entry we're
1401 looking for is closer to the beginning of the
1404 tmp = DECL_NAME (OVL_CURRENT (tmp));
1405 if (!tmp || tmp > name)
1407 else if (tmp < name)
1416 /* If we didn't find it, it might have been a template
1417 conversion operator to a templated type. If there are any,
1418 such template conversion operators will all be overloaded on
1419 the first conversion slot. (Note that we don't look for this
1420 case above so that we will always find specializations
1422 if (IDENTIFIER_TYPENAME_P (name))
1424 i = CLASSTYPE_FIRST_CONVERSION_SLOT;
1425 if (i < len && methods[i])
1427 tmp = OVL_CURRENT (methods[i]);
1428 if (TREE_CODE (tmp) == TEMPLATE_DECL
1429 && DECL_TEMPLATE_CONV_FN_P (tmp))
1438 /* DECL is the result of a qualified name lookup. QUALIFYING_SCOPE is
1439 the class or namespace used to qualify the name. CONTEXT_CLASS is
1440 the class corresponding to the object in which DECL will be used.
1441 Return a possibly modified version of DECL that takes into account
1444 In particular, consider an expression like `B::m' in the context of
1445 a derived class `D'. If `B::m' has been resolved to a BASELINK,
1446 then the most derived class indicated by the BASELINK_BINFO will be
1447 `B', not `D'. This function makes that adjustment. */
1450 adjust_result_of_qualified_name_lookup (tree decl,
1451 tree qualifying_scope,
1454 if (context_class && CLASS_TYPE_P (qualifying_scope)
1455 && DERIVED_FROM_P (qualifying_scope, context_class)
1456 && BASELINK_P (decl))
1460 my_friendly_assert (CLASS_TYPE_P (context_class), 20020808);
1462 /* Look for the QUALIFYING_SCOPE as a base of the
1463 CONTEXT_CLASS. If QUALIFYING_SCOPE is ambiguous, we cannot
1464 be sure yet than an error has occurred; perhaps the function
1465 chosen by overload resolution will be static. */
1466 base = lookup_base (context_class, qualifying_scope,
1467 ba_ignore | ba_quiet, NULL);
1470 BASELINK_ACCESS_BINFO (decl) = base;
1471 BASELINK_BINFO (decl)
1472 = lookup_base (base, BINFO_TYPE (BASELINK_BINFO (decl)),
1473 ba_ignore | ba_quiet,
1482 /* Walk the class hierarchy dominated by TYPE. FN is called for each
1483 type in the hierarchy, in a breadth-first preorder traversal.
1484 If it ever returns a non-NULL value, that value is immediately
1485 returned and the walk is terminated. At each node, FN is passed a
1486 BINFO indicating the path from the curently visited base-class to
1487 TYPE. Before each base-class is walked QFN is called. If the
1488 value returned is nonzero, the base-class is walked; otherwise it
1489 is not. If QFN is NULL, it is treated as a function which always
1490 returns 1. Both FN and QFN are passed the DATA whenever they are
1493 Implementation notes: Uses a circular queue, which starts off on
1494 the stack but gets moved to the malloc arena if it needs to be
1495 enlarged. The underflow and overflow conditions are
1496 indistinguishable except by context: if head == tail and we just
1497 moved the head pointer, the queue is empty, but if we just moved
1498 the tail pointer, the queue is full.
1499 Start with enough room for ten concurrent base classes. That
1500 will be enough for most hierarchies. */
1501 #define BFS_WALK_INITIAL_QUEUE_SIZE 10
1504 bfs_walk (tree binfo,
1505 tree (*fn) (tree, void *),
1506 tree (*qfn) (tree, int, void *),
1509 tree rval = NULL_TREE;
1511 tree bases_initial[BFS_WALK_INITIAL_QUEUE_SIZE];
1512 /* A circular queue of the base classes of BINFO. These will be
1513 built up in breadth-first order, except where QFN prunes the
1516 size_t base_buffer_size = BFS_WALK_INITIAL_QUEUE_SIZE;
1517 tree *base_buffer = bases_initial;
1520 base_buffer[tail++] = binfo;
1522 while (head != tail)
1525 tree binfo = base_buffer[head++];
1526 if (head == base_buffer_size)
1529 /* Is this the one we're looking for? If so, we're done. */
1530 rval = fn (binfo, data);
1534 n_bases = BINFO_N_BASETYPES (binfo);
1535 for (ix = 0; ix != n_bases; ix++)
1540 base_binfo = (*qfn) (binfo, ix, data);
1542 base_binfo = BINFO_BASETYPE (binfo, ix);
1546 base_buffer[tail++] = base_binfo;
1547 if (tail == base_buffer_size)
1551 tree *new_buffer = xmalloc (2 * base_buffer_size
1553 memcpy (&new_buffer[0], &base_buffer[0],
1554 tail * sizeof (tree));
1555 memcpy (&new_buffer[head + base_buffer_size],
1557 (base_buffer_size - head) * sizeof (tree));
1558 if (base_buffer_size != BFS_WALK_INITIAL_QUEUE_SIZE)
1560 base_buffer = new_buffer;
1561 head += base_buffer_size;
1562 base_buffer_size *= 2;
1569 if (base_buffer_size != BFS_WALK_INITIAL_QUEUE_SIZE)
1574 /* Exactly like bfs_walk, except that a depth-first traversal is
1575 performed, and PREFN is called in preorder, while POSTFN is called
1579 dfs_walk_real (tree binfo,
1580 tree (*prefn) (tree, void *),
1581 tree (*postfn) (tree, void *),
1582 tree (*qfn) (tree, int, void *),
1585 tree rval = NULL_TREE;
1587 /* Call the pre-order walking function. */
1590 rval = (*prefn) (binfo, data);
1595 /* Process the basetypes. */
1596 if (BINFO_BASETYPES (binfo))
1598 int i, n = TREE_VEC_LENGTH (BINFO_BASETYPES (binfo));
1599 for (i = 0; i != n; i++)
1604 base_binfo = (*qfn) (binfo, i, data);
1606 base_binfo = BINFO_BASETYPE (binfo, i);
1610 rval = dfs_walk_real (base_binfo, prefn, postfn, qfn, data);
1617 /* Call the post-order walking function. */
1619 rval = (*postfn) (binfo, data);
1624 /* Exactly like bfs_walk, except that a depth-first post-order traversal is
1628 dfs_walk (tree binfo,
1629 tree (*fn) (tree, void *),
1630 tree (*qfn) (tree, int, void *),
1633 return dfs_walk_real (binfo, 0, fn, qfn, data);
1636 /* Check that virtual overrider OVERRIDER is acceptable for base function
1637 BASEFN. Issue diagnostic, and return zero, if unacceptable. */
1640 check_final_overrider (tree overrider, tree basefn)
1642 tree over_type = TREE_TYPE (overrider);
1643 tree base_type = TREE_TYPE (basefn);
1644 tree over_return = TREE_TYPE (over_type);
1645 tree base_return = TREE_TYPE (base_type);
1646 tree over_throw = TYPE_RAISES_EXCEPTIONS (over_type);
1647 tree base_throw = TYPE_RAISES_EXCEPTIONS (base_type);
1650 if (same_type_p (base_return, over_return))
1652 else if ((CLASS_TYPE_P (over_return) && CLASS_TYPE_P (base_return))
1653 || (TREE_CODE (base_return) == TREE_CODE (over_return)
1654 && POINTER_TYPE_P (base_return)))
1656 /* Potentially covariant. */
1657 unsigned base_quals, over_quals;
1659 fail = !POINTER_TYPE_P (base_return);
1662 fail = cp_type_quals (base_return) != cp_type_quals (over_return);
1664 base_return = TREE_TYPE (base_return);
1665 over_return = TREE_TYPE (over_return);
1667 base_quals = cp_type_quals (base_return);
1668 over_quals = cp_type_quals (over_return);
1670 if ((base_quals & over_quals) != over_quals)
1673 if (CLASS_TYPE_P (base_return) && CLASS_TYPE_P (over_return))
1675 tree binfo = lookup_base (over_return, base_return,
1676 ba_check | ba_quiet, NULL);
1682 && can_convert (TREE_TYPE (base_type), TREE_TYPE (over_type)))
1683 /* GNU extension, allow trivial pointer conversions such as
1684 converting to void *, or qualification conversion. */
1686 /* can_convert will permit user defined conversion from a
1687 (reference to) class type. We must reject them. */
1688 over_return = TREE_TYPE (over_type);
1689 if (TREE_CODE (over_return) == REFERENCE_TYPE)
1690 over_return = TREE_TYPE (over_return);
1691 if (CLASS_TYPE_P (over_return))
1701 else if (IDENTIFIER_ERROR_LOCUS (DECL_ASSEMBLER_NAME (overrider)))
1707 cp_error_at ("invalid covariant return type for `%#D'", overrider);
1708 cp_error_at (" overriding `%#D'", basefn);
1712 cp_error_at ("conflicting return type specified for `%#D'",
1714 cp_error_at (" overriding `%#D'", basefn);
1716 SET_IDENTIFIER_ERROR_LOCUS (DECL_ASSEMBLER_NAME (overrider),
1717 DECL_CONTEXT (overrider));
1721 /* Check throw specifier is at least as strict. */
1722 if (!comp_except_specs (base_throw, over_throw, 0))
1724 if (!IDENTIFIER_ERROR_LOCUS (DECL_ASSEMBLER_NAME (overrider)))
1726 cp_error_at ("looser throw specifier for `%#F'", overrider);
1727 cp_error_at (" overriding `%#F'", basefn);
1728 SET_IDENTIFIER_ERROR_LOCUS (DECL_ASSEMBLER_NAME (overrider),
1729 DECL_CONTEXT (overrider));
1737 /* Given a class TYPE, and a function decl FNDECL, look for
1738 virtual functions in TYPE's hierarchy which FNDECL overrides.
1739 We do not look in TYPE itself, only its bases.
1741 Returns nonzero, if we find any. Set FNDECL's DECL_VIRTUAL_P, if we
1742 find that it overrides anything.
1744 We check that every function which is overridden, is correctly
1748 look_for_overrides (tree type, tree fndecl)
1750 tree binfo = TYPE_BINFO (type);
1751 tree basebinfos = BINFO_BASETYPES (binfo);
1752 int nbasebinfos = basebinfos ? TREE_VEC_LENGTH (basebinfos) : 0;
1756 for (ix = 0; ix != nbasebinfos; ix++)
1758 tree basetype = BINFO_TYPE (TREE_VEC_ELT (basebinfos, ix));
1760 if (TYPE_POLYMORPHIC_P (basetype))
1761 found += look_for_overrides_r (basetype, fndecl);
1766 /* Look in TYPE for virtual functions with the same signature as
1770 look_for_overrides_here (tree type, tree fndecl)
1774 if (DECL_MAYBE_IN_CHARGE_DESTRUCTOR_P (fndecl))
1775 ix = CLASSTYPE_DESTRUCTOR_SLOT;
1777 ix = lookup_fnfields_1 (type, DECL_NAME (fndecl));
1780 tree fns = TREE_VEC_ELT (CLASSTYPE_METHOD_VEC (type), ix);
1782 for (; fns; fns = OVL_NEXT (fns))
1784 tree fn = OVL_CURRENT (fns);
1786 if (!DECL_VIRTUAL_P (fn))
1787 /* Not a virtual. */;
1788 else if (DECL_CONTEXT (fn) != type)
1789 /* Introduced with a using declaration. */;
1790 else if (DECL_STATIC_FUNCTION_P (fndecl))
1792 tree btypes = TYPE_ARG_TYPES (TREE_TYPE (fn));
1793 tree dtypes = TYPE_ARG_TYPES (TREE_TYPE (fndecl));
1794 if (compparms (TREE_CHAIN (btypes), dtypes))
1797 else if (same_signature_p (fndecl, fn))
1804 /* Look in TYPE for virtual functions overridden by FNDECL. Check both
1805 TYPE itself and its bases. */
1808 look_for_overrides_r (tree type, tree fndecl)
1810 tree fn = look_for_overrides_here (type, fndecl);
1813 if (DECL_STATIC_FUNCTION_P (fndecl))
1815 /* A static member function cannot match an inherited
1816 virtual member function. */
1817 cp_error_at ("`%#D' cannot be declared", fndecl);
1818 cp_error_at (" since `%#D' declared in base class", fn);
1822 /* It's definitely virtual, even if not explicitly set. */
1823 DECL_VIRTUAL_P (fndecl) = 1;
1824 check_final_overrider (fndecl, fn);
1829 /* We failed to find one declared in this class. Look in its bases. */
1830 return look_for_overrides (type, fndecl);
1833 /* Called via dfs_walk from dfs_get_pure_virtuals. */
1836 dfs_get_pure_virtuals (tree binfo, void *data)
1838 tree type = (tree) data;
1840 /* We're not interested in primary base classes; the derived class
1841 of which they are a primary base will contain the information we
1843 if (!BINFO_PRIMARY_P (binfo))
1847 for (virtuals = BINFO_VIRTUALS (binfo);
1849 virtuals = TREE_CHAIN (virtuals))
1850 if (DECL_PURE_VIRTUAL_P (BV_FN (virtuals)))
1851 CLASSTYPE_PURE_VIRTUALS (type)
1852 = tree_cons (NULL_TREE, BV_FN (virtuals),
1853 CLASSTYPE_PURE_VIRTUALS (type));
1856 BINFO_MARKED (binfo) = 1;
1861 /* Set CLASSTYPE_PURE_VIRTUALS for TYPE. */
1864 get_pure_virtuals (tree type)
1868 /* Clear the CLASSTYPE_PURE_VIRTUALS list; whatever is already there
1869 is going to be overridden. */
1870 CLASSTYPE_PURE_VIRTUALS (type) = NULL_TREE;
1871 /* Now, run through all the bases which are not primary bases, and
1872 collect the pure virtual functions. We look at the vtable in
1873 each class to determine what pure virtual functions are present.
1874 (A primary base is not interesting because the derived class of
1875 which it is a primary base will contain vtable entries for the
1876 pure virtuals in the base class. */
1877 dfs_walk (TYPE_BINFO (type), dfs_get_pure_virtuals, unmarkedp, type);
1878 dfs_walk (TYPE_BINFO (type), dfs_unmark, markedp, type);
1880 /* Put the pure virtuals in dfs order. */
1881 CLASSTYPE_PURE_VIRTUALS (type) = nreverse (CLASSTYPE_PURE_VIRTUALS (type));
1883 for (vbases = CLASSTYPE_VBASECLASSES (type);
1885 vbases = TREE_CHAIN (vbases))
1889 for (virtuals = BINFO_VIRTUALS (TREE_VALUE (vbases));
1891 virtuals = TREE_CHAIN (virtuals))
1893 tree base_fndecl = BV_FN (virtuals);
1894 if (DECL_NEEDS_FINAL_OVERRIDER_P (base_fndecl))
1895 error ("`%#D' needs a final overrider", base_fndecl);
1900 /* DEPTH-FIRST SEARCH ROUTINES. */
1903 markedp (tree derived, int ix, void *data ATTRIBUTE_UNUSED)
1905 tree binfo = BINFO_BASETYPE (derived, ix);
1907 return BINFO_MARKED (binfo) ? binfo : NULL_TREE;
1911 unmarkedp (tree derived, int ix, void *data ATTRIBUTE_UNUSED)
1913 tree binfo = BINFO_BASETYPE (derived, ix);
1915 return !BINFO_MARKED (binfo) ? binfo : NULL_TREE;
1919 marked_pushdecls_p (tree derived, int ix, void *data ATTRIBUTE_UNUSED)
1921 tree binfo = BINFO_BASETYPE (derived, ix);
1923 return (!BINFO_DEPENDENT_BASE_P (binfo)
1924 && BINFO_PUSHDECLS_MARKED (binfo)) ? binfo : NULL_TREE;
1928 unmarked_pushdecls_p (tree derived, int ix, void *data ATTRIBUTE_UNUSED)
1930 tree binfo = BINFO_BASETYPE (derived, ix);
1932 return (!BINFO_DEPENDENT_BASE_P (binfo)
1933 && !BINFO_PUSHDECLS_MARKED (binfo)) ? binfo : NULL_TREE;
1936 /* The worker functions for `dfs_walk'. These do not need to
1937 test anything (vis a vis marking) if they are paired with
1938 a predicate function (above). */
1941 dfs_unmark (tree binfo, void *data ATTRIBUTE_UNUSED)
1943 BINFO_MARKED (binfo) = 0;
1948 /* Debug info for C++ classes can get very large; try to avoid
1949 emitting it everywhere.
1951 Note that this optimization wins even when the target supports
1952 BINCL (if only slightly), and reduces the amount of work for the
1956 maybe_suppress_debug_info (tree t)
1958 /* We can't do the usual TYPE_DECL_SUPPRESS_DEBUG thing with DWARF, which
1959 does not support name references between translation units. It supports
1960 symbolic references between translation units, but only within a single
1961 executable or shared library.
1963 For DWARF 2, we handle TYPE_DECL_SUPPRESS_DEBUG by pretending
1964 that the type was never defined, so we only get the members we
1966 if (write_symbols == DWARF_DEBUG || write_symbols == NO_DEBUG)
1969 /* We might have set this earlier in cp_finish_decl. */
1970 TYPE_DECL_SUPPRESS_DEBUG (TYPE_MAIN_DECL (t)) = 0;
1972 /* If we already know how we're handling this class, handle debug info
1974 if (CLASSTYPE_INTERFACE_KNOWN (t))
1976 if (CLASSTYPE_INTERFACE_ONLY (t))
1977 TYPE_DECL_SUPPRESS_DEBUG (TYPE_MAIN_DECL (t)) = 1;
1978 /* else don't set it. */
1980 /* If the class has a vtable, write out the debug info along with
1982 else if (TYPE_CONTAINS_VPTR_P (t))
1983 TYPE_DECL_SUPPRESS_DEBUG (TYPE_MAIN_DECL (t)) = 1;
1985 /* Otherwise, just emit the debug info normally. */
1988 /* Note that we want debugging information for a base class of a class
1989 whose vtable is being emitted. Normally, this would happen because
1990 calling the constructor for a derived class implies calling the
1991 constructors for all bases, which involve initializing the
1992 appropriate vptr with the vtable for the base class; but in the
1993 presence of optimization, this initialization may be optimized
1994 away, so we tell finish_vtable_vardecl that we want the debugging
1995 information anyway. */
1998 dfs_debug_mark (tree binfo, void *data ATTRIBUTE_UNUSED)
2000 tree t = BINFO_TYPE (binfo);
2002 CLASSTYPE_DEBUG_REQUESTED (t) = 1;
2007 /* Returns BINFO if we haven't already noted that we want debugging
2008 info for this base class. */
2011 dfs_debug_unmarkedp (tree derived, int ix, void *data ATTRIBUTE_UNUSED)
2013 tree binfo = BINFO_BASETYPE (derived, ix);
2015 return (!CLASSTYPE_DEBUG_REQUESTED (BINFO_TYPE (binfo))
2016 ? binfo : NULL_TREE);
2019 /* Write out the debugging information for TYPE, whose vtable is being
2020 emitted. Also walk through our bases and note that we want to
2021 write out information for them. This avoids the problem of not
2022 writing any debug info for intermediate basetypes whose
2023 constructors, and thus the references to their vtables, and thus
2024 the vtables themselves, were optimized away. */
2027 note_debug_info_needed (tree type)
2029 if (TYPE_DECL_SUPPRESS_DEBUG (TYPE_NAME (type)))
2031 TYPE_DECL_SUPPRESS_DEBUG (TYPE_NAME (type)) = 0;
2032 rest_of_type_compilation (type, toplevel_bindings_p ());
2035 dfs_walk (TYPE_BINFO (type), dfs_debug_mark, dfs_debug_unmarkedp, 0);
2038 /* Subroutines of push_class_decls (). */
2041 setup_class_bindings (tree name, int type_binding_p)
2043 tree type_binding = NULL_TREE;
2046 /* If we've already done the lookup for this declaration, we're
2048 if (IDENTIFIER_CLASS_VALUE (name))
2051 /* First, deal with the type binding. */
2054 type_binding = lookup_member (current_class_type, name,
2055 /*protect=*/2, /*want_type=*/true);
2056 if (TREE_CODE (type_binding) == TREE_LIST
2057 && TREE_TYPE (type_binding) == error_mark_node)
2058 /* NAME is ambiguous. */
2059 push_class_level_binding (name, type_binding);
2061 pushdecl_class_level (type_binding);
2064 /* Now, do the value binding. */
2065 value_binding = lookup_member (current_class_type, name,
2066 /*protect=*/2, /*want_type=*/false);
2069 && (TREE_CODE (value_binding) == TYPE_DECL
2070 || DECL_CLASS_TEMPLATE_P (value_binding)
2071 || (TREE_CODE (value_binding) == TREE_LIST
2072 && TREE_TYPE (value_binding) == error_mark_node
2073 && (TREE_CODE (TREE_VALUE (value_binding))
2075 /* We found a type-binding, even when looking for a non-type
2076 binding. This means that we already processed this binding
2078 else if (value_binding)
2080 if (TREE_CODE (value_binding) == TREE_LIST
2081 && TREE_TYPE (value_binding) == error_mark_node)
2082 /* NAME is ambiguous. */
2083 push_class_level_binding (name, value_binding);
2086 if (BASELINK_P (value_binding))
2087 /* NAME is some overloaded functions. */
2088 value_binding = BASELINK_FUNCTIONS (value_binding);
2089 pushdecl_class_level (value_binding);
2094 /* Push class-level declarations for any names appearing in BINFO that
2098 dfs_push_type_decls (tree binfo, void *data ATTRIBUTE_UNUSED)
2103 type = BINFO_TYPE (binfo);
2104 for (fields = TYPE_FIELDS (type); fields; fields = TREE_CHAIN (fields))
2105 if (DECL_NAME (fields) && TREE_CODE (fields) == TYPE_DECL
2106 && !(!same_type_p (type, current_class_type)
2107 && template_self_reference_p (type, fields)))
2108 setup_class_bindings (DECL_NAME (fields), /*type_binding_p=*/1);
2110 /* We can't just use BINFO_MARKED because envelope_add_decl uses
2111 DERIVED_FROM_P, which calls get_base_distance. */
2112 BINFO_PUSHDECLS_MARKED (binfo) = 1;
2117 /* Push class-level declarations for any names appearing in BINFO that
2118 are not TYPE_DECLS. */
2121 dfs_push_decls (tree binfo, void *data)
2123 tree type = BINFO_TYPE (binfo);
2127 for (fields = TYPE_FIELDS (type); fields; fields = TREE_CHAIN (fields))
2128 if (DECL_NAME (fields)
2129 && TREE_CODE (fields) != TYPE_DECL
2130 && TREE_CODE (fields) != USING_DECL
2131 && !DECL_ARTIFICIAL (fields))
2132 setup_class_bindings (DECL_NAME (fields), /*type_binding_p=*/0);
2133 else if (TREE_CODE (fields) == FIELD_DECL
2134 && ANON_AGGR_TYPE_P (TREE_TYPE (fields)))
2135 dfs_push_decls (TYPE_BINFO (TREE_TYPE (fields)), data);
2137 method_vec = (CLASS_TYPE_P (type)
2138 ? CLASSTYPE_METHOD_VEC (type) : NULL_TREE);
2140 if (method_vec && TREE_VEC_LENGTH (method_vec) >= 3)
2145 /* Farm out constructors and destructors. */
2146 end = TREE_VEC_END (method_vec);
2148 for (methods = &TREE_VEC_ELT (method_vec, 2);
2149 methods < end && *methods;
2151 setup_class_bindings (DECL_NAME (OVL_CURRENT (*methods)),
2152 /*type_binding_p=*/0);
2155 BINFO_PUSHDECLS_MARKED (binfo) = 0;
2160 /* When entering the scope of a class, we cache all of the
2161 fields that that class provides within its inheritance
2162 lattice. Where ambiguities result, we mark them
2163 with `error_mark_node' so that if they are encountered
2164 without explicit qualification, we can emit an error
2168 push_class_decls (tree type)
2170 search_stack = push_search_level (search_stack, &search_obstack);
2172 /* Enter type declarations and mark. */
2173 dfs_walk (TYPE_BINFO (type), dfs_push_type_decls, unmarked_pushdecls_p, 0);
2175 /* Enter non-type declarations and unmark. */
2176 dfs_walk (TYPE_BINFO (type), dfs_push_decls, marked_pushdecls_p, 0);
2179 /* Here's a subroutine we need because C lacks lambdas. */
2182 dfs_unuse_fields (tree binfo, void *data ATTRIBUTE_UNUSED)
2184 tree type = TREE_TYPE (binfo);
2187 for (fields = TYPE_FIELDS (type); fields; fields = TREE_CHAIN (fields))
2189 if (TREE_CODE (fields) != FIELD_DECL || DECL_ARTIFICIAL (fields))
2192 TREE_USED (fields) = 0;
2193 if (DECL_NAME (fields) == NULL_TREE
2194 && ANON_AGGR_TYPE_P (TREE_TYPE (fields)))
2195 unuse_fields (TREE_TYPE (fields));
2202 unuse_fields (tree type)
2204 dfs_walk (TYPE_BINFO (type), dfs_unuse_fields, unmarkedp, 0);
2210 /* We haven't pushed a search level when dealing with cached classes,
2211 so we'd better not try to pop it. */
2213 search_stack = pop_search_level (search_stack);
2217 print_search_statistics ()
2219 #ifdef GATHER_STATISTICS
2220 fprintf (stderr, "%d fields searched in %d[%d] calls to lookup_field[_1]\n",
2221 n_fields_searched, n_calls_lookup_field, n_calls_lookup_field_1);
2222 fprintf (stderr, "%d fnfields searched in %d calls to lookup_fnfields\n",
2223 n_outer_fields_searched, n_calls_lookup_fnfields);
2224 fprintf (stderr, "%d calls to get_base_type\n", n_calls_get_base_type);
2225 #else /* GATHER_STATISTICS */
2226 fprintf (stderr, "no search statistics\n");
2227 #endif /* GATHER_STATISTICS */
2231 init_search_processing ()
2233 gcc_obstack_init (&search_obstack);
2237 reinit_search_statistics ()
2239 #ifdef GATHER_STATISTICS
2240 n_fields_searched = 0;
2241 n_calls_lookup_field = 0, n_calls_lookup_field_1 = 0;
2242 n_calls_lookup_fnfields = 0, n_calls_lookup_fnfields_1 = 0;
2243 n_calls_get_base_type = 0;
2244 n_outer_fields_searched = 0;
2245 n_contexts_saved = 0;
2246 #endif /* GATHER_STATISTICS */
2250 add_conversions (tree binfo, void *data)
2253 tree method_vec = CLASSTYPE_METHOD_VEC (BINFO_TYPE (binfo));
2254 tree *conversions = (tree *) data;
2256 /* Some builtin types have no method vector, not even an empty one. */
2260 for (i = 2; i < TREE_VEC_LENGTH (method_vec); ++i)
2262 tree tmp = TREE_VEC_ELT (method_vec, i);
2265 if (!tmp || ! DECL_CONV_FN_P (OVL_CURRENT (tmp)))
2268 name = DECL_NAME (OVL_CURRENT (tmp));
2270 /* Make sure we don't already have this conversion. */
2271 if (! IDENTIFIER_MARKED (name))
2273 *conversions = tree_cons (binfo, tmp, *conversions);
2274 IDENTIFIER_MARKED (name) = 1;
2280 /* Return a TREE_LIST containing all the non-hidden user-defined
2281 conversion functions for TYPE (and its base-classes). The
2282 TREE_VALUE of each node is a FUNCTION_DECL or an OVERLOAD
2283 containing the conversion functions. The TREE_PURPOSE is the BINFO
2284 from which the conversion functions in this node were selected. */
2287 lookup_conversions (tree type)
2290 tree conversions = NULL_TREE;
2292 complete_type (type);
2293 bfs_walk (TYPE_BINFO (type), add_conversions, 0, &conversions);
2295 for (t = conversions; t; t = TREE_CHAIN (t))
2296 IDENTIFIER_MARKED (DECL_NAME (OVL_CURRENT (TREE_VALUE (t)))) = 0;
2307 /* Check whether the empty class indicated by EMPTY_BINFO is also present
2308 at offset 0 in COMPARE_TYPE, and set found_overlap if so. */
2311 dfs_check_overlap (tree empty_binfo, void *data)
2313 struct overlap_info *oi = (struct overlap_info *) data;
2315 for (binfo = TYPE_BINFO (oi->compare_type);
2317 binfo = BINFO_BASETYPE (binfo, 0))
2319 if (BINFO_TYPE (binfo) == BINFO_TYPE (empty_binfo))
2321 oi->found_overlap = 1;
2324 else if (BINFO_BASETYPES (binfo) == NULL_TREE)
2331 /* Trivial function to stop base traversal when we find something. */
2334 dfs_no_overlap_yet (tree derived, int ix, void *data)
2336 tree binfo = BINFO_BASETYPE (derived, ix);
2337 struct overlap_info *oi = (struct overlap_info *) data;
2339 return !oi->found_overlap ? binfo : NULL_TREE;
2342 /* Returns nonzero if EMPTY_TYPE or any of its bases can also be found at
2343 offset 0 in NEXT_TYPE. Used in laying out empty base class subobjects. */
2346 types_overlap_p (tree empty_type, tree next_type)
2348 struct overlap_info oi;
2350 if (! IS_AGGR_TYPE (next_type))
2352 oi.compare_type = next_type;
2353 oi.found_overlap = 0;
2354 dfs_walk (TYPE_BINFO (empty_type), dfs_check_overlap,
2355 dfs_no_overlap_yet, &oi);
2356 return oi.found_overlap;
2359 /* Given a vtable VAR, determine which of the inherited classes the vtable
2360 inherits (in a loose sense) functions from.
2362 FIXME: This does not work with the new ABI. */
2365 binfo_for_vtable (tree var)
2367 tree main_binfo = TYPE_BINFO (DECL_CONTEXT (var));
2368 tree binfos = TYPE_BINFO_BASETYPES (BINFO_TYPE (main_binfo));
2369 int n_baseclasses = CLASSTYPE_N_BASECLASSES (BINFO_TYPE (main_binfo));
2372 for (i = 0; i < n_baseclasses; i++)
2374 tree base_binfo = TREE_VEC_ELT (binfos, i);
2375 if (base_binfo != NULL_TREE && BINFO_VTABLE (base_binfo) == var)
2379 /* If no secondary base classes matched, return the primary base, if
2381 if (CLASSTYPE_HAS_PRIMARY_BASE_P (BINFO_TYPE (main_binfo)))
2382 return get_primary_binfo (main_binfo);
2387 /* Returns the binfo of the first direct or indirect virtual base derived
2388 from BINFO, or NULL if binfo is not via virtual. */
2391 binfo_from_vbase (tree binfo)
2393 for (; binfo; binfo = BINFO_INHERITANCE_CHAIN (binfo))
2395 if (TREE_VIA_VIRTUAL (binfo))
2401 /* Returns the binfo of the first direct or indirect virtual base derived
2402 from BINFO up to the TREE_TYPE, LIMIT, or NULL if binfo is not
2406 binfo_via_virtual (tree binfo, tree limit)
2408 for (; binfo && (!limit || !same_type_p (BINFO_TYPE (binfo), limit));
2409 binfo = BINFO_INHERITANCE_CHAIN (binfo))
2411 if (TREE_VIA_VIRTUAL (binfo))
2417 /* BINFO is a base binfo in the complete type BINFO_TYPE (HERE).
2418 Find the equivalent binfo within whatever graph HERE is located.
2419 This is the inverse of original_binfo. */
2422 copied_binfo (tree binfo, tree here)
2424 tree result = NULL_TREE;
2426 if (TREE_VIA_VIRTUAL (binfo))
2430 for (t = here; BINFO_INHERITANCE_CHAIN (t);
2431 t = BINFO_INHERITANCE_CHAIN (t))
2434 result = purpose_member (BINFO_TYPE (binfo),
2435 CLASSTYPE_VBASECLASSES (BINFO_TYPE (t)));
2436 result = TREE_VALUE (result);
2438 else if (BINFO_INHERITANCE_CHAIN (binfo))
2443 base_binfos = copied_binfo (BINFO_INHERITANCE_CHAIN (binfo), here);
2444 base_binfos = BINFO_BASETYPES (base_binfos);
2445 n = TREE_VEC_LENGTH (base_binfos);
2446 for (ix = 0; ix != n; ix++)
2448 tree base = TREE_VEC_ELT (base_binfos, ix);
2450 if (BINFO_TYPE (base) == BINFO_TYPE (binfo))
2459 my_friendly_assert (BINFO_TYPE (here) == BINFO_TYPE (binfo), 20030202);
2463 my_friendly_assert (result, 20030202);
2467 /* BINFO is some base binfo of HERE, within some other
2468 hierachy. Return the equivalent binfo, but in the hierarchy
2469 dominated by HERE. This is the inverse of copied_binfo. If BINFO
2470 is not a base binfo of HERE, returns NULL_TREE. */
2473 original_binfo (tree binfo, tree here)
2477 if (BINFO_TYPE (binfo) == BINFO_TYPE (here))
2479 else if (TREE_VIA_VIRTUAL (binfo))
2481 result = purpose_member (BINFO_TYPE (binfo),
2482 CLASSTYPE_VBASECLASSES (BINFO_TYPE (here)));
2484 result = TREE_VALUE (result);
2486 else if (BINFO_INHERITANCE_CHAIN (binfo))
2490 base_binfos = original_binfo (BINFO_INHERITANCE_CHAIN (binfo), here);
2495 base_binfos = BINFO_BASETYPES (base_binfos);
2496 n = TREE_VEC_LENGTH (base_binfos);
2497 for (ix = 0; ix != n; ix++)
2499 tree base = TREE_VEC_ELT (base_binfos, ix);
2501 if (BINFO_TYPE (base) == BINFO_TYPE (binfo))