/* Breadth-first and depth-first routines for searching multiple-inheritance lattice for GNU C++. Copyright (C) 1987-2024 Free Software Foundation, Inc. Contributed by Michael Tiemann (tiemann@cygnus.com) This file is part of GCC. GCC is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 3, or (at your option) any later version. GCC is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with GCC; see the file COPYING3. If not see . */ /* High-level class interface. */ #include "config.h" #include "system.h" #include "coretypes.h" #include "cp-tree.h" #include "intl.h" #include "toplev.h" #include "spellcheck-tree.h" #include "stringpool.h" #include "attribs.h" #include "tree-inline.h" static int is_subobject_of_p (tree, tree); static tree dfs_lookup_base (tree, void *); static tree dfs_dcast_hint_pre (tree, void *); static tree dfs_dcast_hint_post (tree, void *); static tree dfs_debug_mark (tree, void *); static int check_hidden_convs (tree, int, int, tree, tree, tree); static tree split_conversions (tree, tree, tree, tree); static int lookup_conversions_r (tree, int, int, tree, tree, tree *); static int look_for_overrides_r (tree, tree); static tree lookup_field_r (tree, void *); static tree dfs_accessible_post (tree, void *); static tree dfs_walk_once_accessible (tree, bool, tree (*pre_fn) (tree, void *), tree (*post_fn) (tree, void *), void *data); static tree dfs_access_in_type (tree, void *); static access_kind access_in_type (tree, tree); static tree dfs_get_pure_virtuals (tree, void *); /* Data for lookup_base and its workers. */ struct lookup_base_data_s { HOST_WIDE_INT offset; /* Offset we want, or -1 if any. */ tree t; /* type being searched. */ tree base; /* The base type we're looking for. */ tree binfo; /* Found binfo. */ bool via_virtual; /* Found via a virtual path. */ bool ambiguous; /* Found multiply ambiguous */ bool repeated_base; /* Whether there are repeated bases in the hierarchy. */ bool want_any; /* Whether we want any matching binfo. */ }; /* Worker function for lookup_base. See if we've found the desired base and update DATA_ (a pointer to LOOKUP_BASE_DATA_S). */ static tree dfs_lookup_base (tree binfo, void *data_) { struct lookup_base_data_s *data = (struct lookup_base_data_s *) data_; if (data->offset != -1) { /* We're looking for the type at a particular offset. */ int comp = compare_tree_int (BINFO_OFFSET (binfo), data->offset); if (comp > 0) /* Don't bother looking into bases laid out later; even if they do virtually inherit from the base we want, we can get there by another path. */ return dfs_skip_bases; else if (comp != 0 && SAME_BINFO_TYPE_P (BINFO_TYPE (binfo), data->base)) /* Right type, wrong offset. */ return dfs_skip_bases; /* Fall through. */ } if (SAME_BINFO_TYPE_P (BINFO_TYPE (binfo), data->base)) { if (!data->binfo) { data->binfo = binfo; data->via_virtual = binfo_via_virtual (data->binfo, data->t) != NULL_TREE; if (!data->repeated_base) /* If there are no repeated bases, we can stop now. */ return binfo; if (data->want_any && !data->via_virtual) /* If this is a non-virtual base, then we can't do better. */ return binfo; return dfs_skip_bases; } else { gcc_assert (binfo != data->binfo); /* We've found more than one matching binfo. */ if (!data->want_any) { /* This is immediately ambiguous. */ data->binfo = NULL_TREE; data->ambiguous = true; return error_mark_node; } /* Prefer one via a non-virtual path. */ if (!binfo_via_virtual (binfo, data->t)) { data->binfo = binfo; data->via_virtual = false; return binfo; } /* There must be repeated bases, otherwise we'd have stopped on the first base we found. */ return dfs_skip_bases; } } return NULL_TREE; } /* This deals with bug PR17314. DECL is a declaration and BINFO represents a class that has attempted (but failed) to access DECL. Examine the parent binfos of BINFO and determine whether any of them had private access to DECL. If they did, return the parent binfo. This helps in figuring out the correct error message to show (if the parents had access, it's their fault for not giving sufficient access to BINFO). If no parents had access, return NULL_TREE. */ tree get_parent_with_private_access (tree decl, tree binfo) { /* Only BINFOs should come through here. */ gcc_assert (TREE_CODE (binfo) == TREE_BINFO); tree base_binfo = NULL_TREE; /* Iterate through immediate parent classes. */ for (int i = 0; BINFO_BASE_ITERATE (binfo, i, base_binfo); i++) { /* This parent had private access. Therefore that's why BINFO can't access DECL. */ if (access_in_type (BINFO_TYPE (base_binfo), decl) == ak_private) return base_binfo; } /* None of the parents had access. Note: it's impossible for one of the parents to have had public or protected access to DECL, since then BINFO would have been able to access DECL too. */ return NULL_TREE; } /* Returns true if type BASE is accessible in T. (BASE is known to be a (possibly non-proper) base class of T.) If CONSIDER_LOCAL_P is true, consider any special access of the current scope, or access bestowed by friendship. */ bool accessible_base_p (tree t, tree base, bool consider_local_p) { tree decl; /* [class.access.base] A base class is said to be accessible if an invented public member of the base class is accessible. If BASE is a non-proper base, this condition is trivially true. */ if (same_type_p (t, base)) return true; /* Rather than inventing a public member, we use the implicit public typedef created in the scope of every class. */ decl = TYPE_FIELDS (base); while (!DECL_SELF_REFERENCE_P (decl)) decl = DECL_CHAIN (decl); while (ANON_AGGR_TYPE_P (t)) t = TYPE_CONTEXT (t); return accessible_p (t, decl, consider_local_p); } /* Lookup BASE in the hierarchy dominated by T. Do access checking as ACCESS specifies. Return the binfo we discover. If KIND_PTR is non-NULL, fill with information about what kind of base we discovered. If OFFSET is other than -1, only match at that offset. If the base is inaccessible, or ambiguous, then error_mark_node is returned. If the tf_error bit of COMPLAIN is not set, no error is issued. */ tree lookup_base (tree t, tree base, base_access access, base_kind *kind_ptr, tsubst_flags_t complain, HOST_WIDE_INT offset /* = -1 */) { tree binfo; tree t_binfo; base_kind bk; /* "Nothing" is definitely not derived from Base. */ if (t == NULL_TREE) { if (kind_ptr) *kind_ptr = bk_not_base; return NULL_TREE; } if (t == error_mark_node || base == error_mark_node) { if (kind_ptr) *kind_ptr = bk_not_base; return error_mark_node; } gcc_assert (TYPE_P (base)); if (!TYPE_P (t)) { t_binfo = t; t = BINFO_TYPE (t); } else { t = complete_type (TYPE_MAIN_VARIANT (t)); if (dependent_type_p (t)) if (tree open = currently_open_class (t)) t = open; t_binfo = TYPE_BINFO (t); } base = TYPE_MAIN_VARIANT (base); /* If BASE is incomplete, it can't be a base of T--and instantiating it might cause an error. */ if (t_binfo && CLASS_TYPE_P (base) && COMPLETE_OR_OPEN_TYPE_P (base)) { struct lookup_base_data_s data; data.t = t; data.base = base; data.binfo = NULL_TREE; data.ambiguous = data.via_virtual = false; data.repeated_base = (offset == -1) && CLASSTYPE_REPEATED_BASE_P (t); data.want_any = access == ba_any; data.offset = offset; dfs_walk_once (t_binfo, dfs_lookup_base, NULL, &data); binfo = data.binfo; if (!binfo) bk = data.ambiguous ? bk_ambig : bk_not_base; else if (binfo == t_binfo) bk = bk_same_type; else if (data.via_virtual) bk = bk_via_virtual; else bk = bk_proper_base; } else { binfo = NULL_TREE; bk = bk_not_base; } /* Check that the base is unambiguous and accessible. */ if (access != ba_any) switch (bk) { case bk_not_base: break; case bk_ambig: if (complain & tf_error) error ("%qT is an ambiguous base of %qT", base, t); binfo = error_mark_node; break; default: if ((access & ba_check_bit) /* If BASE is incomplete, then BASE and TYPE are probably the same, in which case BASE is accessible. If they are not the same, then TYPE is invalid. In that case, there's no need to issue another error here, and there's no implicit typedef to use in the code that follows, so we skip the check. */ && COMPLETE_TYPE_P (base) && !accessible_base_p (t, base, !(access & ba_ignore_scope))) { if (complain & tf_error) error ("%qT is an inaccessible base of %qT", base, t); binfo = error_mark_node; bk = bk_inaccessible; } break; } if (kind_ptr) *kind_ptr = bk; return binfo; } /* Data for dcast_base_hint walker. */ struct dcast_data_s { tree subtype; /* The base type we're looking for. */ int virt_depth; /* Number of virtual bases encountered from most derived. */ tree offset; /* Best hint offset discovered so far. */ bool repeated_base; /* Whether there are repeated bases in the hierarchy. */ }; /* Worker for dcast_base_hint. Search for the base type being cast from. */ static tree dfs_dcast_hint_pre (tree binfo, void *data_) { struct dcast_data_s *data = (struct dcast_data_s *) data_; if (BINFO_VIRTUAL_P (binfo)) data->virt_depth++; if (SAME_BINFO_TYPE_P (BINFO_TYPE (binfo), data->subtype)) { if (data->virt_depth) { data->offset = ssize_int (-1); return data->offset; } if (data->offset) data->offset = ssize_int (-3); else data->offset = BINFO_OFFSET (binfo); return data->repeated_base ? dfs_skip_bases : data->offset; } return NULL_TREE; } /* Worker for dcast_base_hint. Track the virtual depth. */ static tree dfs_dcast_hint_post (tree binfo, void *data_) { struct dcast_data_s *data = (struct dcast_data_s *) data_; if (BINFO_VIRTUAL_P (binfo)) data->virt_depth--; return NULL_TREE; } /* The dynamic cast runtime needs a hint about how the static SUBTYPE type started from is related to the required TARGET type, in order to optimize the inheritance graph search. This information is independent of the current context, and ignores private paths, hence get_base_distance is inappropriate. Return a TREE specifying the base offset, BOFF. BOFF >= 0, there is only one public non-virtual SUBTYPE base at offset BOFF, and there are no public virtual SUBTYPE bases. BOFF == -1, SUBTYPE occurs as multiple public virtual or non-virtual bases. BOFF == -2, SUBTYPE is not a public base. BOFF == -3, SUBTYPE occurs as multiple public non-virtual bases. */ tree dcast_base_hint (tree subtype, tree target) { struct dcast_data_s data; data.subtype = subtype; data.virt_depth = 0; data.offset = NULL_TREE; data.repeated_base = CLASSTYPE_REPEATED_BASE_P (target); dfs_walk_once_accessible (TYPE_BINFO (target), /*friends=*/false, dfs_dcast_hint_pre, dfs_dcast_hint_post, &data); return data.offset ? data.offset : ssize_int (-2); } /* Search for a member with name NAME in a multiple inheritance lattice specified by TYPE. If it does not exist, return NULL_TREE. If the member is ambiguously referenced, return `error_mark_node'. Otherwise, return a DECL with the indicated name. If WANT_TYPE is true, type declarations are preferred. */ /* Return the FUNCTION_DECL, RECORD_TYPE, UNION_TYPE, or NAMESPACE_DECL corresponding to the innermost non-block scope. */ tree current_scope (void) { /* There are a number of cases we need to be aware of here: current_class_type current_function_decl global NULL NULL fn-local NULL SET class-local SET NULL class->fn SET SET fn->class SET SET Those last two make life interesting. If we're in a function which is itself inside a class, we need decls to go into the fn's decls (our second case below). But if we're in a class and the class itself is inside a function, we need decls to go into the decls for the class. To achieve this last goal, we must see if, when both current_class_ptr and current_function_decl are set, the class was declared inside that function. If so, we know to put the decls into the class's scope. */ if (current_function_decl && current_class_type && ((DECL_FUNCTION_MEMBER_P (current_function_decl) && same_type_p (DECL_CONTEXT (current_function_decl), current_class_type)) || (DECL_FRIEND_CONTEXT (current_function_decl) && same_type_p (DECL_FRIEND_CONTEXT (current_function_decl), current_class_type)))) return current_function_decl; if (current_class_type) return current_class_type; if (current_function_decl) return current_function_decl; return current_namespace; } /* Returns nonzero if we are currently in a function scope. Note that this function returns zero if we are within a local class, but not within a member function body of the local class. */ int at_function_scope_p (void) { tree cs = current_scope (); /* Also check cfun to make sure that we're really compiling this function (as opposed to having set current_function_decl for access checking or some such). */ return (cs && TREE_CODE (cs) == FUNCTION_DECL && cfun && cfun->decl == current_function_decl); } /* Returns true if the innermost active scope is a class scope. */ bool at_class_scope_p (void) { tree cs = current_scope (); return cs && TYPE_P (cs); } /* Returns true if the innermost active scope is a namespace scope. */ bool at_namespace_scope_p (void) { tree cs = current_scope (); return cs && TREE_CODE (cs) == NAMESPACE_DECL; } /* Return the scope of DECL, as appropriate when doing name-lookup. */ tree context_for_name_lookup (tree decl) { /* [class.union] For the purposes of name lookup, after the anonymous union definition, the members of the anonymous union are considered to have been defined in the scope in which the anonymous union is declared. */ tree context = DECL_CONTEXT (decl); while (context && TYPE_P (context) && (ANON_AGGR_TYPE_P (context) || UNSCOPED_ENUM_P (context))) context = TYPE_CONTEXT (context); if (!context) context = global_namespace; return context; } /* Like the above, but always return a type, because it's simpler for member handling to refer to the anonymous aggr rather than a function. */ tree type_context_for_name_lookup (tree decl) { tree context = DECL_P (decl) ? DECL_CONTEXT (decl) : decl; gcc_checking_assert (CLASS_TYPE_P (context)); while (context && TYPE_P (context) && ANON_AGGR_TYPE_P (context)) { tree next = TYPE_CONTEXT (context); if (!TYPE_P (next)) break; context = next; } return context; } /* Returns true iff DECL is declared in TYPE. */ static bool member_declared_in_type (tree decl, tree type) { /* A normal declaration obviously counts. */ if (context_for_name_lookup (decl) == type) return true; /* So does a using or access declaration. */ if (DECL_LANG_SPECIFIC (decl) && !DECL_DISCRIMINATOR_P (decl) && purpose_member (type, DECL_ACCESS (decl))) return true; return false; } /* The accessibility routines use BINFO_ACCESS for scratch space during the computation of the accessibility of some declaration. */ /* Avoid walking up past a declaration of the member. */ static tree dfs_access_in_type_pre (tree binfo, void *data) { tree decl = (tree) data; tree type = BINFO_TYPE (binfo); if (member_declared_in_type (decl, type)) return dfs_skip_bases; return NULL_TREE; } #define BINFO_ACCESS(NODE) \ ((access_kind) ((TREE_PUBLIC (NODE) << 1) | TREE_PRIVATE (NODE))) /* Set the access associated with NODE to ACCESS. */ #define SET_BINFO_ACCESS(NODE, ACCESS) \ ((TREE_PUBLIC (NODE) = ((ACCESS) & 2) != 0), \ (TREE_PRIVATE (NODE) = ((ACCESS) & 1) != 0)) /* Called from access_in_type via dfs_walk. Calculate the access to DATA (which is really a DECL) in BINFO. */ static tree dfs_access_in_type (tree binfo, void *data) { tree decl = (tree) data; tree type = BINFO_TYPE (binfo); access_kind access = ak_none; if (context_for_name_lookup (decl) == type) { /* If we have descended to the scope of DECL, just note the appropriate access. */ if (TREE_PRIVATE (decl)) access = ak_private; else if (TREE_PROTECTED (decl)) access = ak_protected; else access = ak_public; } else { /* First, check for an access-declaration that gives us more access to the DECL. */ if (DECL_LANG_SPECIFIC (decl) && !DECL_DISCRIMINATOR_P (decl)) { tree decl_access = purpose_member (type, DECL_ACCESS (decl)); if (decl_access) { decl_access = TREE_VALUE (decl_access); if (decl_access == access_public_node) access = ak_public; else if (decl_access == access_protected_node) access = ak_protected; else if (decl_access == access_private_node) access = ak_private; else gcc_unreachable (); } } if (!access) { int i; tree base_binfo; vec *accesses; /* Otherwise, scan our baseclasses, and pick the most favorable access. */ accesses = BINFO_BASE_ACCESSES (binfo); for (i = 0; BINFO_BASE_ITERATE (binfo, i, base_binfo); i++) { tree base_access = (*accesses)[i]; access_kind base_access_now = BINFO_ACCESS (base_binfo); if (base_access_now == ak_none || base_access_now == ak_private) /* If it was not accessible in the base, or only accessible as a private member, we can't access it all. */ base_access_now = ak_none; else if (base_access == access_protected_node) /* Public and protected members in the base become protected here. */ base_access_now = ak_protected; else if (base_access == access_private_node) /* Public and protected members in the base become private here. */ base_access_now = ak_private; /* See if the new access, via this base, gives more access than our previous best access. */ if (base_access_now != ak_none && (access == ak_none || base_access_now < access)) { access = base_access_now; /* If the new access is public, we can't do better. */ if (access == ak_public) break; } } } } /* Note the access to DECL in TYPE. */ SET_BINFO_ACCESS (binfo, access); return NULL_TREE; } /* Return the access to DECL in TYPE. */ static access_kind access_in_type (tree type, tree decl) { tree binfo = TYPE_BINFO (type); /* We must take into account [class.paths] If a name can be reached by several paths through a multiple inheritance graph, the access is that of the path that gives most access. The algorithm we use is to make a post-order depth-first traversal of the base-class hierarchy. As we come up the tree, we annotate each node with the most lenient access. */ dfs_walk_once (binfo, dfs_access_in_type_pre, dfs_access_in_type, decl); return BINFO_ACCESS (binfo); } /* Returns nonzero if it is OK to access DECL named in TYPE through an object of OTYPE in the context of DERIVED. */ static int protected_accessible_p (tree decl, tree derived, tree type, tree otype) { /* We're checking this clause from [class.access.base] m as a member of N is protected, and the reference occurs in a member or friend of class N, or in a member or friend of a class P derived from N, where m as a member of P is public, private or protected. Here DERIVED is a possible P, DECL is m and TYPE is N. */ /* If DERIVED isn't derived from N, then it can't be a P. */ if (!DERIVED_FROM_P (type, derived)) return 0; /* DECL_NONSTATIC_MEMBER_P won't work for USING_DECLs. */ decl = strip_using_decl (decl); /* We don't expect or support dependent decls. */ gcc_assert (TREE_CODE (decl) != USING_DECL); /* [class.protected] When a friend or a member function of a derived class references a protected non-static member of a base class, an access check applies in addition to those described earlier in clause _class.access_) Except when forming a pointer to member (_expr.unary.op_), the access must be through a pointer to, reference to, or object of the derived class itself (or any class derived from that class) (_expr.ref_). If the access is to form a pointer to member, the nested-name-specifier shall name the derived class (or any class derived from that class). */ if (DECL_NONSTATIC_MEMBER_P (decl) && !DERIVED_FROM_P (derived, otype)) return 0; return 1; } /* Returns nonzero if SCOPE is a type or a friend of a type which would be able to access DECL through TYPE. OTYPE is the type of the object. */ static int friend_accessible_p (tree scope, tree decl, tree type, tree otype) { /* We're checking this clause from [class.access.base] m as a member of N is protected, and the reference occurs in a member or friend of class N, or in a member or friend of a class P derived from N, where m as a member of P is public, private or protected. Here DECL is m and TYPE is N. SCOPE is the current context, and we check all its possible Ps. */ tree befriending_classes; tree t; if (!scope) return 0; if (is_global_friend (scope)) return 1; /* Is SCOPE itself a suitable P? */ if (TYPE_P (scope) && protected_accessible_p (decl, scope, type, otype)) return 1; if (DECL_DECLARES_FUNCTION_P (scope)) befriending_classes = DECL_BEFRIENDING_CLASSES (scope); else if (TYPE_P (scope)) befriending_classes = CLASSTYPE_BEFRIENDING_CLASSES (scope); else return 0; for (t = befriending_classes; t; t = TREE_CHAIN (t)) if (protected_accessible_p (decl, TREE_VALUE (t), type, otype)) return 1; /* Nested classes have the same access as their enclosing types, as per DR 45 (this is a change from C++98). */ if (TYPE_P (scope)) if (friend_accessible_p (TYPE_CONTEXT (scope), decl, type, otype)) return 1; if (DECL_DECLARES_FUNCTION_P (scope)) { /* Perhaps this SCOPE is a member of a class which is a friend. */ if (DECL_CLASS_SCOPE_P (scope) && friend_accessible_p (DECL_CONTEXT (scope), decl, type, otype)) return 1; /* Perhaps SCOPE is a friend function defined inside a class from which DECL is accessible. */ if (tree fctx = DECL_FRIEND_CONTEXT (scope)) if (friend_accessible_p (fctx, decl, type, otype)) return 1; } /* Maybe scope's template is a friend. */ if (tree tinfo = get_template_info (scope)) { tree tmpl = TI_TEMPLATE (tinfo); if (DECL_CLASS_TEMPLATE_P (tmpl)) tmpl = TREE_TYPE (tmpl); else tmpl = DECL_TEMPLATE_RESULT (tmpl); if (tmpl != scope) { /* Increment processing_template_decl to make sure that dependent_type_p works correctly. */ ++processing_template_decl; int ret = friend_accessible_p (tmpl, decl, type, otype); --processing_template_decl; if (ret) return 1; } } /* If is_friend is true, we should have found a befriending class. */ gcc_checking_assert (!is_friend (type, scope)); return 0; } struct dfs_accessible_data { tree decl; tree object_type; }; /* Avoid walking up past a declaration of the member. */ static tree dfs_accessible_pre (tree binfo, void *data) { dfs_accessible_data *d = (dfs_accessible_data *)data; tree type = BINFO_TYPE (binfo); if (member_declared_in_type (d->decl, type)) return dfs_skip_bases; return NULL_TREE; } /* Called via dfs_walk_once_accessible from accessible_p */ static tree dfs_accessible_post (tree binfo, void *data) { /* access_in_type already set BINFO_ACCESS for us. */ access_kind access = BINFO_ACCESS (binfo); tree N = BINFO_TYPE (binfo); dfs_accessible_data *d = (dfs_accessible_data *)data; tree decl = d->decl; tree scope = current_nonlambda_scope (); /* A member m is accessible at the point R when named in class N if */ switch (access) { case ak_none: return NULL_TREE; case ak_public: /* m as a member of N is public, or */ return binfo; case ak_private: { /* m as a member of N is private, and R occurs in a member or friend of class N, or */ if (scope && TREE_CODE (scope) != NAMESPACE_DECL && is_friend (N, scope)) return binfo; return NULL_TREE; } case ak_protected: { /* m as a member of N is protected, and R occurs in a member or friend of class N, or in a member or friend of a class P derived from N, where m as a member of P is public, private, or protected */ if (friend_accessible_p (scope, decl, N, d->object_type)) return binfo; return NULL_TREE; } default: gcc_unreachable (); } } /* Like accessible_p below, but within a template returns true iff DECL is accessible in TYPE to all possible instantiations of the template. */ int accessible_in_template_p (tree type, tree decl) { int save_ptd = processing_template_decl; processing_template_decl = 0; int val = accessible_p (type, decl, false); processing_template_decl = save_ptd; return val; } /* DECL is a declaration from a base class of TYPE, which was the class used to name DECL. Return nonzero if, in the current context, DECL is accessible. If TYPE is actually a BINFO node, then we can tell in what context the access is occurring by looking at the most derived class along the path indicated by BINFO. If CONSIDER_LOCAL is true, do consider special access the current scope or friendship thereof we might have. */ int accessible_p (tree type, tree decl, bool consider_local_p) { tree binfo; access_kind access; /* If this declaration is in a block or namespace scope, there's no access control. */ if (!TYPE_P (context_for_name_lookup (decl))) return 1; /* There is no need to perform access checks inside a thunk. */ if (current_function_decl && DECL_THUNK_P (current_function_decl)) return 1; tree otype = NULL_TREE; if (!TYPE_P (type)) { /* When accessing a non-static member, the most derived type in the binfo chain is the type of the object; remember that type for protected_accessible_p. */ for (tree b = type; b; b = BINFO_INHERITANCE_CHAIN (b)) otype = BINFO_TYPE (b); type = BINFO_TYPE (type); } else otype = type; /* Anonymous unions don't have their own access. */ if (ANON_AGGR_TYPE_P (type)) type = type_context_for_name_lookup (type); /* [class.access.base] A member m is accessible when named in class N if --m as a member of N is public, or --m as a member of N is private, and the reference occurs in a member or friend of class N, or --m as a member of N is protected, and the reference occurs in a member or friend of class N, or in a member or friend of a class P derived from N, where m as a member of P is public, private or protected, or --there exists a base class B of N that is accessible at the point of reference, and m is accessible when named in class B. We walk the base class hierarchy, checking these conditions. */ /* We walk using TYPE_BINFO (type) because access_in_type will set BINFO_ACCESS on it and its bases. */ binfo = TYPE_BINFO (type); /* Compute the accessibility of DECL in the class hierarchy dominated by type. */ access = access_in_type (type, decl); if (access == ak_public) return 1; /* If we aren't considering the point of reference, only the first bullet applies. */ if (!consider_local_p) return 0; dfs_accessible_data d = { decl, otype }; /* Walk the hierarchy again, looking for a base class that allows access. */ return dfs_walk_once_accessible (binfo, /*friends=*/true, dfs_accessible_pre, dfs_accessible_post, &d) != NULL_TREE; } struct lookup_field_info { /* The type in which we're looking. */ tree type; /* The name of the field for which we're looking. */ tree name; /* If non-NULL, the current result of the lookup. */ tree rval; /* The path to RVAL. */ tree rval_binfo; /* If non-NULL, the lookup was ambiguous, and this is a list of the candidates. */ tree ambiguous; /* If nonzero, we are looking for types, not data members. */ int want_type; }; /* True for a class member means that it is shared between all objects of that class. [class.member.lookup]:If the resulting set of declarations are not all from sub-objects of the same type, or the set has a non-static member and includes members from distinct sub-objects, there is an ambiguity and the program is ill-formed. This function checks that T contains no non-static members. */ bool shared_member_p (tree t) { if (VAR_P (t) || TREE_CODE (t) == TYPE_DECL || TREE_CODE (t) == CONST_DECL) return true; if (is_overloaded_fn (t)) { for (ovl_iterator iter (get_fns (t)); iter; ++iter) { tree decl = strip_using_decl (*iter); if (TREE_CODE (decl) == USING_DECL) /* Conservatively assume a dependent using-declaration might resolve to a non-static member. */ return false; if (DECL_OBJECT_MEMBER_FUNCTION_P (decl)) return false; } return true; } return false; } /* Routine to see if the sub-object denoted by the binfo PARENT can be found as a base class and sub-object of the object denoted by BINFO. */ static int is_subobject_of_p (tree parent, tree binfo) { tree probe; for (probe = parent; probe; probe = BINFO_INHERITANCE_CHAIN (probe)) { if (probe == binfo) return 1; if (BINFO_VIRTUAL_P (probe)) return (binfo_for_vbase (BINFO_TYPE (probe), BINFO_TYPE (binfo)) != NULL_TREE); } return 0; } /* DATA is really a struct lookup_field_info. Look for a field with the name indicated there in BINFO. If this function returns a non-NULL value it is the result of the lookup. Called from lookup_field via breadth_first_search. */ static tree lookup_field_r (tree binfo, void *data) { struct lookup_field_info *lfi = (struct lookup_field_info *) data; tree type = BINFO_TYPE (binfo); tree nval = NULL_TREE; /* If this is a dependent base, don't look in it. */ if (BINFO_DEPENDENT_BASE_P (binfo)) return NULL_TREE; /* If this base class is hidden by the best-known value so far, we don't need to look. */ if (lfi->rval_binfo && BINFO_INHERITANCE_CHAIN (binfo) == lfi->rval_binfo && !BINFO_VIRTUAL_P (binfo)) return dfs_skip_bases; nval = get_class_binding (type, lfi->name, lfi->want_type); /* If there is no declaration with the indicated name in this type, then there's nothing to do. */ if (!nval) goto done; /* If the lookup already found a match, and the new value doesn't hide the old one, we might have an ambiguity. */ if (lfi->rval_binfo && !is_subobject_of_p (lfi->rval_binfo, binfo)) { if (nval == lfi->rval && shared_member_p (nval)) /* The two things are really the same. */ ; else if (is_subobject_of_p (binfo, lfi->rval_binfo)) /* The previous value hides the new one. */ ; else { /* We have a real ambiguity. We keep a chain of all the candidates. */ if (!lfi->ambiguous && lfi->rval) { /* This is the first time we noticed an ambiguity. Add what we previously thought was a reasonable candidate to the list. */ lfi->ambiguous = tree_cons (NULL_TREE, lfi->rval, NULL_TREE); TREE_TYPE (lfi->ambiguous) = error_mark_node; } /* Add the new value. */ if (TREE_CODE (nval) == TREE_LIST) lfi->ambiguous = chainon (nval, lfi->ambiguous); else { lfi->ambiguous = tree_cons (NULL_TREE, nval, lfi->ambiguous); TREE_TYPE (lfi->ambiguous) = error_mark_node; } } } else { if (TREE_CODE (nval) == TREE_LIST) { lfi->ambiguous = chainon (nval, lfi->ambiguous); lfi->rval = TREE_VALUE (nval); } else lfi->rval = nval; lfi->rval_binfo = binfo; } done: /* Don't look for constructors or destructors in base classes. */ if (IDENTIFIER_CDTOR_P (lfi->name)) return dfs_skip_bases; return NULL_TREE; } /* Return a "baselink" with BASELINK_BINFO, BASELINK_ACCESS_BINFO, BASELINK_FUNCTIONS, and BASELINK_OPTYPE set to BINFO, ACCESS_BINFO, FUNCTIONS, and OPTYPE respectively. */ tree build_baselink (tree binfo, tree access_binfo, tree functions, tree optype) { tree baselink; gcc_assert (OVL_P (functions) || TREE_CODE (functions) == TEMPLATE_ID_EXPR); gcc_assert (!optype || TYPE_P (optype)); gcc_assert (TREE_TYPE (functions)); baselink = make_node (BASELINK); TREE_TYPE (baselink) = TREE_TYPE (functions); BASELINK_BINFO (baselink) = binfo; BASELINK_ACCESS_BINFO (baselink) = access_binfo; BASELINK_FUNCTIONS (baselink) = functions; BASELINK_OPTYPE (baselink) = optype; if (binfo == access_binfo && TYPE_BEING_DEFINED (BINFO_TYPE (access_binfo))) BASELINK_FUNCTIONS_MAYBE_INCOMPLETE_P (baselink) = true; return baselink; } /* Look for a member named NAME in an inheritance lattice dominated by XBASETYPE. If PROTECT is 0 or two, we do not check access. If it is 1, we enforce accessibility. If PROTECT is zero, then, for an ambiguous lookup, we return NULL. If PROTECT is 1, we issue error messages about inaccessible or ambiguous lookup. If PROTECT is 2, we return a TREE_LIST whose TREE_TYPE is error_mark_node and whose TREE_VALUEs are the list of ambiguous candidates. WANT_TYPE is 1 when we should only return TYPE_DECLs. If nothing can be found return NULL_TREE and do not issue an error. If non-NULL, failure information is written back to AFI. */ tree lookup_member (tree xbasetype, tree name, int protect, bool want_type, tsubst_flags_t complain, access_failure_info *afi /* = NULL */) { tree rval, rval_binfo = NULL_TREE; tree type = NULL_TREE, basetype_path = NULL_TREE; struct lookup_field_info lfi; /* rval_binfo is the binfo associated with the found member, note, this can be set with useful information, even when rval is not set, because it must deal with ALL members, not just non-function members. It is used for ambiguity checking and the hidden checks. Whereas rval is only set if a proper (not hidden) non-function member is found. */ if (name == error_mark_node || xbasetype == NULL_TREE || xbasetype == error_mark_node) return NULL_TREE; gcc_assert (identifier_p (name)); if (TREE_CODE (xbasetype) == TREE_BINFO) { type = BINFO_TYPE (xbasetype); basetype_path = xbasetype; } else { if (!RECORD_OR_UNION_CODE_P (TREE_CODE (xbasetype))) return NULL_TREE; type = xbasetype; xbasetype = NULL_TREE; } type = complete_type (type); /* Make sure we're looking for a member of the current instantiation in the right partial specialization. */ if (dependent_type_p (type)) if (tree t = currently_open_class (type)) type = t; if (!basetype_path) basetype_path = TYPE_BINFO (type); if (!basetype_path) return NULL_TREE; memset (&lfi, 0, sizeof (lfi)); lfi.type = type; lfi.name = name; lfi.want_type = want_type; dfs_walk_all (basetype_path, &lookup_field_r, NULL, &lfi); rval = lfi.rval; rval_binfo = lfi.rval_binfo; if (rval_binfo) type = BINFO_TYPE (rval_binfo); if (lfi.ambiguous) { if (protect == 0) return NULL_TREE; else if (protect == 1) { if (complain & tf_error) { error ("request for member %qD is ambiguous", name); print_candidates (lfi.ambiguous); } return error_mark_node; } else if (protect == 2) return lfi.ambiguous; } if (!rval) return NULL_TREE; /* [class.access] In the case of overloaded function names, access control is applied to the function selected by overloaded resolution. We cannot check here, even if RVAL is only a single non-static member function, since we do not know what the "this" pointer will be. For: class A { protected: void f(); }; class B : public A { void g(A *p) { f(); // OK p->f(); // Not OK. } }; only the first call to "f" is valid. However, if the function is static, we can check. */ if (protect == 1 && !really_overloaded_fn (rval)) { tree decl = is_overloaded_fn (rval) ? get_first_fn (rval) : rval; decl = strip_using_decl (decl); /* A dependent USING_DECL will be checked after tsubsting. */ if (TREE_CODE (decl) != USING_DECL && !DECL_IOBJ_MEMBER_FUNCTION_P (decl) && !perform_or_defer_access_check (basetype_path, decl, decl, complain, afi)) return error_mark_node; } if (is_overloaded_fn (rval) /* Don't use a BASELINK for class-scope deduction guides since they're not actually member functions. */ && !dguide_name_p (name)) rval = build_baselink (rval_binfo, basetype_path, rval, (IDENTIFIER_CONV_OP_P (name) ? TREE_TYPE (name): NULL_TREE)); return rval; } /* Helper class for lookup_member_fuzzy. */ class lookup_field_fuzzy_info { public: lookup_field_fuzzy_info (bool want_type_p) : m_want_type_p (want_type_p), m_candidates () {} void fuzzy_lookup_field (tree type); /* If true, we are looking for types, not data members. */ bool m_want_type_p; /* The result: a vec of identifiers. */ auto_vec m_candidates; }; /* Locate all fields within TYPE, append them to m_candidates. */ void lookup_field_fuzzy_info::fuzzy_lookup_field (tree type) { if (!CLASS_TYPE_P (type)) return; for (tree field = TYPE_FIELDS (type); field; field = DECL_CHAIN (field)) { if (m_want_type_p && !DECL_DECLARES_TYPE_P (field)) continue; if (!DECL_NAME (field)) continue; if (is_lambda_ignored_entity (field)) continue; /* Ignore special identifiers with space at the end like cdtor or conversion op identifiers. */ if (TREE_CODE (DECL_NAME (field)) == IDENTIFIER_NODE) if (unsigned int len = IDENTIFIER_LENGTH (DECL_NAME (field))) if (IDENTIFIER_POINTER (DECL_NAME (field))[len - 1] == ' ') continue; m_candidates.safe_push (DECL_NAME (field)); } } /* Helper function for lookup_member_fuzzy, called via dfs_walk_all DATA is really a lookup_field_fuzzy_info. Look for a field with the name indicated there in BINFO. Gathers pertinent identifiers into m_candidates. */ static tree lookup_field_fuzzy_r (tree binfo, void *data) { lookup_field_fuzzy_info *lffi = (lookup_field_fuzzy_info *) data; tree type = BINFO_TYPE (binfo); lffi->fuzzy_lookup_field (type); return NULL_TREE; } /* Like lookup_member, but try to find the closest match for NAME, rather than an exact match, and return an identifier (or NULL_TREE). Do not complain. */ tree lookup_member_fuzzy (tree xbasetype, tree name, bool want_type_p) { tree type = NULL_TREE, basetype_path = NULL_TREE; class lookup_field_fuzzy_info lffi (want_type_p); /* rval_binfo is the binfo associated with the found member, note, this can be set with useful information, even when rval is not set, because it must deal with ALL members, not just non-function members. It is used for ambiguity checking and the hidden checks. Whereas rval is only set if a proper (not hidden) non-function member is found. */ if (name == error_mark_node || xbasetype == NULL_TREE || xbasetype == error_mark_node) return NULL_TREE; gcc_assert (identifier_p (name)); if (TREE_CODE (xbasetype) == TREE_BINFO) { type = BINFO_TYPE (xbasetype); basetype_path = xbasetype; } else { if (!RECORD_OR_UNION_CODE_P (TREE_CODE (xbasetype))) return NULL_TREE; type = xbasetype; xbasetype = NULL_TREE; } type = complete_type (type); /* Make sure we're looking for a member of the current instantiation in the right partial specialization. */ if (flag_concepts && dependent_type_p (type)) type = currently_open_class (type); if (!basetype_path) basetype_path = TYPE_BINFO (type); if (!basetype_path) return NULL_TREE; /* Populate lffi.m_candidates. */ dfs_walk_all (basetype_path, &lookup_field_fuzzy_r, NULL, &lffi); return find_closest_identifier (name, &lffi.m_candidates); } /* Like lookup_member, except that if we find a function member we return NULL_TREE. */ tree lookup_field (tree xbasetype, tree name, int protect, bool want_type) { tree rval = lookup_member (xbasetype, name, protect, want_type, tf_warning_or_error); /* Ignore functions, but propagate the ambiguity list. */ if (!error_operand_p (rval) && (rval && BASELINK_P (rval))) return NULL_TREE; return rval; } /* Like lookup_member, except that if we find a non-function member we return NULL_TREE. */ tree lookup_fnfields (tree xbasetype, tree name, int protect, tsubst_flags_t complain) { tree rval = lookup_member (xbasetype, name, protect, /*want_type=*/false, complain); /* Ignore non-functions, but propagate the ambiguity list. */ if (!error_operand_p (rval) && (rval && !BASELINK_P (rval))) return NULL_TREE; return rval; } /* DECL is the result of a qualified name lookup. QUALIFYING_SCOPE is the class or namespace used to qualify the name. CONTEXT_CLASS is the class corresponding to the object in which DECL will be used. Return a possibly modified version of DECL that takes into account the CONTEXT_CLASS. In particular, consider an expression like `B::m' in the context of a derived class `D'. If `B::m' has been resolved to a BASELINK, then the most derived class indicated by the BASELINK_BINFO will be `B', not `D'. This function makes that adjustment. */ tree adjust_result_of_qualified_name_lookup (tree decl, tree qualifying_scope, tree context_class) { if (context_class && context_class != error_mark_node && CLASS_TYPE_P (context_class) && CLASS_TYPE_P (qualifying_scope) && DERIVED_FROM_P (qualifying_scope, context_class) && BASELINK_P (decl)) { tree base; /* Look for the QUALIFYING_SCOPE as a base of the CONTEXT_CLASS. Because we do not yet know which function will be chosen by overload resolution, we cannot yet check either accessibility or ambiguity -- in either case, the choice of a static member function might make the usage valid. */ base = lookup_base (context_class, qualifying_scope, ba_unique, NULL, tf_none); if (base && base != error_mark_node) { BASELINK_ACCESS_BINFO (decl) = base; tree decl_binfo = lookup_base (base, BINFO_TYPE (BASELINK_BINFO (decl)), ba_unique, NULL, tf_none); if (decl_binfo && decl_binfo != error_mark_node) BASELINK_BINFO (decl) = decl_binfo; } } if (BASELINK_P (decl)) BASELINK_QUALIFIED_P (decl) = true; return decl; } /* Walk the class hierarchy within BINFO, in a depth-first traversal. PRE_FN is called in preorder, while POST_FN is called in postorder. If PRE_FN returns DFS_SKIP_BASES, child binfos will not be walked. If PRE_FN or POST_FN returns a different non-NULL value, that value is immediately returned and the walk is terminated. One of PRE_FN and POST_FN can be NULL. At each node, PRE_FN and POST_FN are passed the binfo to examine and the caller's DATA value. All paths are walked, thus virtual and morally virtual binfos can be multiply walked. */ tree dfs_walk_all (tree binfo, tree (*pre_fn) (tree, void *), tree (*post_fn) (tree, void *), void *data) { tree rval; unsigned ix; tree base_binfo; /* Call the pre-order walking function. */ if (pre_fn) { rval = pre_fn (binfo, data); if (rval) { if (rval == dfs_skip_bases) goto skip_bases; return rval; } } /* Find the next child binfo to walk. */ for (ix = 0; BINFO_BASE_ITERATE (binfo, ix, base_binfo); ix++) { rval = dfs_walk_all (base_binfo, pre_fn, post_fn, data); if (rval) return rval; } skip_bases: /* Call the post-order walking function. */ if (post_fn) { rval = post_fn (binfo, data); gcc_assert (rval != dfs_skip_bases); return rval; } return NULL_TREE; } /* Worker for dfs_walk_once. This behaves as dfs_walk_all, except that binfos are walked at most once. */ static tree dfs_walk_once_r (tree binfo, tree (*pre_fn) (tree, void *), tree (*post_fn) (tree, void *), hash_set *pset, void *data) { tree rval; unsigned ix; tree base_binfo; /* Call the pre-order walking function. */ if (pre_fn) { rval = pre_fn (binfo, data); if (rval) { if (rval == dfs_skip_bases) goto skip_bases; return rval; } } /* Find the next child binfo to walk. */ for (ix = 0; BINFO_BASE_ITERATE (binfo, ix, base_binfo); ix++) { if (BINFO_VIRTUAL_P (base_binfo)) if (pset->add (base_binfo)) continue; rval = dfs_walk_once_r (base_binfo, pre_fn, post_fn, pset, data); if (rval) return rval; } skip_bases: /* Call the post-order walking function. */ if (post_fn) { rval = post_fn (binfo, data); gcc_assert (rval != dfs_skip_bases); return rval; } return NULL_TREE; } /* Like dfs_walk_all, except that binfos are not multiply walked. For non-diamond shaped hierarchies this is the same as dfs_walk_all. For diamond shaped hierarchies we must mark the virtual bases, to avoid multiple walks. */ tree dfs_walk_once (tree binfo, tree (*pre_fn) (tree, void *), tree (*post_fn) (tree, void *), void *data) { static int active = 0; /* We must not be called recursively. */ tree rval; gcc_assert (pre_fn || post_fn); gcc_assert (!active); active++; if (!CLASSTYPE_DIAMOND_SHAPED_P (BINFO_TYPE (binfo))) /* We are not diamond shaped, and therefore cannot encounter the same binfo twice. */ rval = dfs_walk_all (binfo, pre_fn, post_fn, data); else { hash_set pset; rval = dfs_walk_once_r (binfo, pre_fn, post_fn, &pset, data); } active--; return rval; } /* Worker function for dfs_walk_once_accessible. Behaves like dfs_walk_once_r, except (a) FRIENDS_P is true if special access given by the current context should be considered, (b) ONCE indicates whether bases should be marked during traversal. */ static tree dfs_walk_once_accessible_r (tree binfo, bool friends_p, hash_set *pset, tree (*pre_fn) (tree, void *), tree (*post_fn) (tree, void *), void *data) { tree rval = NULL_TREE; unsigned ix; tree base_binfo; /* Call the pre-order walking function. */ if (pre_fn) { rval = pre_fn (binfo, data); if (rval) { if (rval == dfs_skip_bases) goto skip_bases; return rval; } } /* Find the next child binfo to walk. */ for (ix = 0; BINFO_BASE_ITERATE (binfo, ix, base_binfo); ix++) { bool mark = pset && BINFO_VIRTUAL_P (base_binfo); if (mark && pset->contains (base_binfo)) continue; /* If the base is inherited via private or protected inheritance, then we can't see it, unless we are a friend of the current binfo. */ if (BINFO_BASE_ACCESS (binfo, ix) != access_public_node) { tree scope; if (!friends_p) continue; scope = current_scope (); if (!scope || TREE_CODE (scope) == NAMESPACE_DECL || !is_friend (BINFO_TYPE (binfo), scope)) continue; } if (mark) pset->add (base_binfo); rval = dfs_walk_once_accessible_r (base_binfo, friends_p, pset, pre_fn, post_fn, data); if (rval) return rval; } skip_bases: /* Call the post-order walking function. */ if (post_fn) { rval = post_fn (binfo, data); gcc_assert (rval != dfs_skip_bases); return rval; } return NULL_TREE; } /* Like dfs_walk_once except that only accessible bases are walked. FRIENDS_P indicates whether friendship of the local context should be considered when determining accessibility. */ static tree dfs_walk_once_accessible (tree binfo, bool friends_p, tree (*pre_fn) (tree, void *), tree (*post_fn) (tree, void *), void *data) { hash_set *pset = NULL; if (CLASSTYPE_DIAMOND_SHAPED_P (BINFO_TYPE (binfo))) pset = new hash_set; tree rval = dfs_walk_once_accessible_r (binfo, friends_p, pset, pre_fn, post_fn, data); if (pset) delete pset; return rval; } /* Return true iff the code of T is CODE, and it has compatible type with TYPE. */ static bool matches_code_and_type_p (tree t, enum tree_code code, tree type) { if (TREE_CODE (t) != code) return false; if (!cxx_types_compatible_p (TREE_TYPE (t), type)) return false; return true; } /* Subroutine of direct_accessor_p and reference_accessor_p. Determine if COMPONENT_REF is a simple field lookup of this->FIELD_DECL. We expect a tree of the form: >>. */ static bool field_access_p (tree component_ref, tree field_decl, tree field_type) { if (!matches_code_and_type_p (component_ref, COMPONENT_REF, field_type)) return false; tree indirect_ref = TREE_OPERAND (component_ref, 0); if (!INDIRECT_REF_P (indirect_ref)) return false; tree ptr = STRIP_NOPS (TREE_OPERAND (indirect_ref, 0)); if (!is_object_parameter (ptr)) return false; /* Must access the correct field. */ if (TREE_OPERAND (component_ref, 1) != field_decl) return false; return true; } /* Subroutine of field_accessor_p. Assuming that INIT_EXPR has already had its code and type checked, determine if it is a simple accessor for FIELD_DECL (of type FIELD_TYPE). Specifically, a simple accessor within struct S of the form: T get_field () { return m_field; } should have a constexpr_fn_retval (saved_tree) of the form: >>>>. */ static bool direct_accessor_p (tree init_expr, tree field_decl, tree field_type) { tree result_decl = TREE_OPERAND (init_expr, 0); if (!matches_code_and_type_p (result_decl, RESULT_DECL, field_type)) return false; tree component_ref = STRIP_NOPS (TREE_OPERAND (init_expr, 1)); if (!field_access_p (component_ref, field_decl, field_type)) return false; return true; } /* Subroutine of field_accessor_p. Assuming that INIT_EXPR has already had its code and type checked, determine if it is a "reference" accessor for FIELD_DECL (of type FIELD_REFERENCE_TYPE). Specifically, a simple accessor within struct S of the form: T& get_field () { return m_field; } should have a constexpr_fn_retval (saved_tree) of the form: > >>>>>. */ static bool reference_accessor_p (tree init_expr, tree field_decl, tree field_type, tree field_reference_type) { tree result_decl = TREE_OPERAND (init_expr, 0); if (!matches_code_and_type_p (result_decl, RESULT_DECL, field_reference_type)) return false; tree field_pointer_type = build_pointer_type (field_type); tree addr_expr = STRIP_NOPS (TREE_OPERAND (init_expr, 1)); if (!matches_code_and_type_p (addr_expr, ADDR_EXPR, field_pointer_type)) return false; tree component_ref = STRIP_NOPS (TREE_OPERAND (addr_expr, 0)); if (!field_access_p (component_ref, field_decl, field_type)) return false; return true; } /* Return the class of the `this' or explicit object parameter of FN. */ static tree class_of_object_parm (const_tree fn) { tree fntype = TREE_TYPE (fn); if (DECL_XOBJ_MEMBER_FUNCTION_P (fn)) return non_reference (TREE_VALUE (TYPE_ARG_TYPES (fntype))); return class_of_this_parm (fntype); } /* Return true if FN is an accessor method for FIELD_DECL. i.e. a method of the form { return FIELD; }, with no conversions. If CONST_P, then additionally require that FN be a const method. */ static bool field_accessor_p (tree fn, tree field_decl, bool const_p) { if (TREE_CODE (fn) != FUNCTION_DECL) return false; /* We don't yet support looking up static data, just fields. */ if (TREE_CODE (field_decl) != FIELD_DECL) return false; if (!DECL_OBJECT_MEMBER_FUNCTION_P (fn)) return false; /* If the field is accessed via a const "this" argument, verify that the "this" parameter is const. */ if (const_p) { tree this_class = class_of_object_parm (fn); if (!TYPE_READONLY (this_class)) return false; } tree saved_tree = DECL_SAVED_TREE (fn); if (saved_tree == NULL_TREE) return false; /* Attempt to extract a single return value from the function, if it has one. */ tree retval = constexpr_fn_retval (saved_tree); if (retval == NULL_TREE || retval == error_mark_node) return false; /* Require an INIT_EXPR. */ if (TREE_CODE (retval) != INIT_EXPR) return false; tree init_expr = retval; /* Determine if this is a simple accessor within struct S of the form: T get_field () { return m_field; }. */ tree field_type = TREE_TYPE (field_decl); if (cxx_types_compatible_p (TREE_TYPE (init_expr), field_type)) return direct_accessor_p (init_expr, field_decl, field_type); /* Failing that, determine if it is an accessor of the form: T& get_field () { return m_field; }. */ tree field_reference_type = cp_build_reference_type (field_type, false); if (cxx_types_compatible_p (TREE_TYPE (init_expr), field_reference_type)) return reference_accessor_p (init_expr, field_decl, field_type, field_reference_type); return false; } /* Callback data for dfs_locate_field_accessor_pre. */ class locate_field_data { public: locate_field_data (tree field_decl_, bool const_p_) : field_decl (field_decl_), const_p (const_p_) {} tree field_decl; bool const_p; }; /* Return a FUNCTION_DECL that is an "accessor" method for DATA, a FIELD_DECL, callable via binfo, if one exists, otherwise return NULL_TREE. Callback for dfs_walk_once_accessible for use within locate_field_accessor. */ static tree dfs_locate_field_accessor_pre (tree binfo, void *data) { locate_field_data *lfd = (locate_field_data *)data; tree type = BINFO_TYPE (binfo); vec *member_vec; tree fn; size_t i; if (!CLASS_TYPE_P (type)) return NULL_TREE; member_vec = CLASSTYPE_MEMBER_VEC (type); if (!member_vec) return NULL_TREE; for (i = 0; vec_safe_iterate (member_vec, i, &fn); ++i) if (fn) if (field_accessor_p (fn, lfd->field_decl, lfd->const_p)) return fn; return NULL_TREE; } /* Return a FUNCTION_DECL that is an "accessor" method for FIELD_DECL, callable via BASETYPE_PATH, if one exists, otherwise return NULL_TREE. */ tree locate_field_accessor (tree basetype_path, tree field_decl, bool const_p) { if (TREE_CODE (basetype_path) != TREE_BINFO) return NULL_TREE; /* Walk the hierarchy, looking for a method of some base class that allows access to the field. */ locate_field_data lfd (field_decl, const_p); return dfs_walk_once_accessible (basetype_path, /*friends=*/true, dfs_locate_field_accessor_pre, NULL, &lfd); } /* Check throw specifier of OVERRIDER is at least as strict as the one of BASEFN. This is due to [except.spec]: "If a virtual function has a non-throwing exception specification, all declarations, including the definition, of any function that overrides that virtual function in any derived class shall have a non-throwing exception specification, unless the overriding function is defined as deleted." */ bool maybe_check_overriding_exception_spec (tree overrider, tree basefn) { maybe_instantiate_noexcept (basefn); maybe_instantiate_noexcept (overrider); tree base_throw = TYPE_RAISES_EXCEPTIONS (TREE_TYPE (basefn)); tree over_throw = TYPE_RAISES_EXCEPTIONS (TREE_TYPE (overrider)); if (DECL_INVALID_OVERRIDER_P (overrider) /* CWG 1351 added the "unless the overriding function is defined as deleted" wording. */ || DECL_DELETED_FN (overrider)) return true; /* Can't check this yet. Pretend this is fine and let noexcept_override_late_checks check this later. */ if (UNPARSED_NOEXCEPT_SPEC_P (base_throw) || UNPARSED_NOEXCEPT_SPEC_P (over_throw)) return true; /* We also have to defer checking when we're in a template and couldn't instantiate & evaluate the noexcept to true/false. */ if (processing_template_decl) if ((base_throw && base_throw != noexcept_true_spec && base_throw != noexcept_false_spec) || (over_throw && over_throw != noexcept_true_spec && over_throw != noexcept_false_spec)) return true; if (!comp_except_specs (base_throw, over_throw, ce_derived)) { auto_diagnostic_group d; error ("looser exception specification on overriding virtual function " "%q+#F", overrider); inform (DECL_SOURCE_LOCATION (basefn), "overridden function is %q#F", basefn); DECL_INVALID_OVERRIDER_P (overrider) = 1; return false; } return true; } /* Check that virtual overrider OVERRIDER is acceptable for base function BASEFN. Issue diagnostic, and return zero, if unacceptable. */ static int check_final_overrider (tree overrider, tree basefn) { tree over_type = TREE_TYPE (overrider); tree base_type = TREE_TYPE (basefn); tree over_return = fndecl_declared_return_type (overrider); tree base_return = fndecl_declared_return_type (basefn); int fail = 0; if (DECL_INVALID_OVERRIDER_P (overrider)) return 0; if (same_type_p (base_return, over_return)) /* OK */; else if ((CLASS_TYPE_P (over_return) && CLASS_TYPE_P (base_return)) || (TREE_CODE (base_return) == TREE_CODE (over_return) && INDIRECT_TYPE_P (base_return))) { /* Potentially covariant. */ unsigned base_quals, over_quals; fail = !INDIRECT_TYPE_P (base_return); if (!fail) { if (cp_type_quals (base_return) != cp_type_quals (over_return)) fail = 1; if (TYPE_REF_P (base_return) && (TYPE_REF_IS_RVALUE (base_return) != TYPE_REF_IS_RVALUE (over_return))) fail = 1; base_return = TREE_TYPE (base_return); over_return = TREE_TYPE (over_return); } base_quals = cp_type_quals (base_return); over_quals = cp_type_quals (over_return); if ((base_quals & over_quals) != over_quals) fail = 1; if (CLASS_TYPE_P (base_return) && CLASS_TYPE_P (over_return)) { /* Strictly speaking, the standard requires the return type to be complete even if it only differs in cv-quals, but that seems like a bug in the wording. */ if (!same_type_ignoring_top_level_qualifiers_p (base_return, over_return)) { tree binfo = lookup_base (over_return, base_return, ba_check, NULL, tf_none); if (!binfo || binfo == error_mark_node) fail = 1; } } else if (can_convert_standard (TREE_TYPE (base_type), TREE_TYPE (over_type), tf_warning_or_error)) /* GNU extension, allow trivial pointer conversions such as converting to void *, or qualification conversion. */ { auto_diagnostic_group d; if (pedwarn (DECL_SOURCE_LOCATION (overrider), 0, "invalid covariant return type for %q#D", overrider)) inform (DECL_SOURCE_LOCATION (basefn), "overridden function is %q#D", basefn); } else fail = 2; } else fail = 2; if (!fail) /* OK */; else { auto_diagnostic_group d; if (fail == 1) error ("invalid covariant return type for %q+#D", overrider); else error ("conflicting return type specified for %q+#D", overrider); inform (DECL_SOURCE_LOCATION (basefn), "overridden function is %q#D", basefn); DECL_INVALID_OVERRIDER_P (overrider) = 1; return 0; } if (!maybe_check_overriding_exception_spec (overrider, basefn)) return 0; /* Check for conflicting type attributes. But leave transaction_safe for set_one_vmethod_tm_attributes. */ if (!comp_type_attributes (over_type, base_type) && !tx_safe_fn_type_p (base_type) && !tx_safe_fn_type_p (over_type)) { auto_diagnostic_group d; error ("conflicting type attributes specified for %q+#D", overrider); inform (DECL_SOURCE_LOCATION (basefn), "overridden function is %q#D", basefn); DECL_INVALID_OVERRIDER_P (overrider) = 1; return 0; } /* A consteval virtual function shall not override a virtual function that is not consteval. A consteval virtual function shall not be overridden by a virtual function that is not consteval. */ if (DECL_IMMEDIATE_FUNCTION_P (overrider) != DECL_IMMEDIATE_FUNCTION_P (basefn)) { auto_diagnostic_group d; if (DECL_IMMEDIATE_FUNCTION_P (overrider)) error ("% function %q+D overriding non-% " "function", overrider); else error ("non-% function %q+D overriding % " "function", overrider); inform (DECL_SOURCE_LOCATION (basefn), "overridden function is %qD", basefn); DECL_INVALID_OVERRIDER_P (overrider) = 1; return 0; } /* A function declared transaction_safe_dynamic that overrides a function declared transaction_safe (but not transaction_safe_dynamic) is ill-formed. */ if (tx_safe_fn_type_p (base_type) && lookup_attribute ("transaction_safe_dynamic", DECL_ATTRIBUTES (overrider)) && !lookup_attribute ("transaction_safe_dynamic", DECL_ATTRIBUTES (basefn))) { auto_diagnostic_group d; error_at (DECL_SOURCE_LOCATION (overrider), "%qD declared %", overrider); inform (DECL_SOURCE_LOCATION (basefn), "overriding %qD declared %", basefn); } if (DECL_DELETED_FN (basefn) != DECL_DELETED_FN (overrider)) { if (DECL_DELETED_FN (overrider)) { auto_diagnostic_group d; error ("deleted function %q+D overriding non-deleted function", overrider); inform (DECL_SOURCE_LOCATION (basefn), "overridden function is %qD", basefn); maybe_explain_implicit_delete (overrider); } else { auto_diagnostic_group d; error ("non-deleted function %q+D overriding deleted function", overrider); inform (DECL_SOURCE_LOCATION (basefn), "overridden function is %qD", basefn); } return 0; } if (!DECL_HAS_CONTRACTS_P (basefn) && DECL_HAS_CONTRACTS_P (overrider)) { auto_diagnostic_group d; error ("function with contracts %q+D overriding contractless function", overrider); inform (DECL_SOURCE_LOCATION (basefn), "overridden function is %qD", basefn); return 0; } else if (DECL_HAS_CONTRACTS_P (basefn) && !DECL_HAS_CONTRACTS_P (overrider)) { /* We're inheriting basefn's contracts; create a copy of them but replace references to their parms to our parms. */ inherit_base_contracts (overrider, basefn); } else if (DECL_HAS_CONTRACTS_P (basefn) && DECL_HAS_CONTRACTS_P (overrider)) { /* We're in the process of completing the overrider's class, which means our conditions definitely are not parsed so simply chain on the basefn for later checking. Note that OVERRIDER's contracts will have been fully parsed at the point the deferred match is run. */ defer_guarded_contract_match (overrider, basefn, DECL_CONTRACTS (basefn)); } if (DECL_FINAL_P (basefn)) { auto_diagnostic_group d; error ("virtual function %q+D overriding final function", overrider); inform (DECL_SOURCE_LOCATION (basefn), "overridden function is %qD", basefn); return 0; } return 1; } /* Given a class TYPE, and a function decl FNDECL, look for virtual functions in TYPE's hierarchy which FNDECL overrides. We do not look in TYPE itself, only its bases. Returns nonzero, if we find any. Set FNDECL's DECL_VIRTUAL_P, if we find that it overrides anything. We check that every function which is overridden, is correctly overridden. */ int look_for_overrides (tree type, tree fndecl) { tree binfo = TYPE_BINFO (type); tree base_binfo; int ix; int found = 0; /* A constructor for a class T does not override a function T in a base class. */ if (DECL_CONSTRUCTOR_P (fndecl)) return 0; for (ix = 0; BINFO_BASE_ITERATE (binfo, ix, base_binfo); ix++) { tree basetype = BINFO_TYPE (base_binfo); if (TYPE_POLYMORPHIC_P (basetype)) found += look_for_overrides_r (basetype, fndecl); } return found; } /* Look in TYPE for virtual functions with the same signature as FNDECL. */ tree look_for_overrides_here (tree type, tree fndecl) { tree ovl = get_class_binding (type, DECL_NAME (fndecl)); for (ovl_iterator iter (ovl); iter; ++iter) { tree fn = *iter; if (!DECL_VIRTUAL_P (fn)) /* Not a virtual. */; else if (DECL_CONTEXT (fn) != type) /* Introduced with a using declaration. */; else if (DECL_STATIC_FUNCTION_P (fndecl) || DECL_XOBJ_MEMBER_FUNCTION_P (fndecl)) { tree btypes = TYPE_ARG_TYPES (TREE_TYPE (fn)); tree dtypes = TYPE_ARG_TYPES (TREE_TYPE (fndecl)); dtypes = DECL_XOBJ_MEMBER_FUNCTION_P (fndecl) ? TREE_CHAIN (dtypes) : dtypes; if (compparms (TREE_CHAIN (btypes), dtypes)) return fn; } else if (same_signature_p (fndecl, fn)) return fn; } return NULL_TREE; } /* Look in TYPE for virtual functions overridden by FNDECL. Check both TYPE itself and its bases. */ static int look_for_overrides_r (tree type, tree fndecl) { tree fn = look_for_overrides_here (type, fndecl); if (fn) { if (DECL_STATIC_FUNCTION_P (fndecl)) { /* A static member function cannot match an inherited virtual member function. */ auto_diagnostic_group d; error ("%q+#D cannot be declared", fndecl); error (" since %q+#D declared in base class", fn); } else if (DECL_XOBJ_MEMBER_FUNCTION_P (fndecl)) { auto_diagnostic_group d; error_at (DECL_SOURCE_LOCATION (fndecl), "explicit object member function " "overrides virtual function"); inform (DECL_SOURCE_LOCATION (fn), "virtual function declared here"); } else { /* It's definitely virtual, even if not explicitly set. */ DECL_VIRTUAL_P (fndecl) = 1; check_final_overrider (fndecl, fn); } return 1; } /* We failed to find one declared in this class. Look in its bases. */ return look_for_overrides (type, fndecl); } /* Called via dfs_walk from dfs_get_pure_virtuals. */ static tree dfs_get_pure_virtuals (tree binfo, void *data) { tree type = (tree) data; /* We're not interested in primary base classes; the derived class of which they are a primary base will contain the information we need. */ if (!BINFO_PRIMARY_P (binfo)) { tree virtuals; for (virtuals = BINFO_VIRTUALS (binfo); virtuals; virtuals = TREE_CHAIN (virtuals)) if (DECL_PURE_VIRTUAL_P (BV_FN (virtuals))) vec_safe_push (CLASSTYPE_PURE_VIRTUALS (type), BV_FN (virtuals)); } return NULL_TREE; } /* Set CLASSTYPE_PURE_VIRTUALS for TYPE. */ void get_pure_virtuals (tree type) { /* Clear the CLASSTYPE_PURE_VIRTUALS list; whatever is already there is going to be overridden. */ CLASSTYPE_PURE_VIRTUALS (type) = NULL; /* Now, run through all the bases which are not primary bases, and collect the pure virtual functions. We look at the vtable in each class to determine what pure virtual functions are present. (A primary base is not interesting because the derived class of which it is a primary base will contain vtable entries for the pure virtuals in the base class. */ dfs_walk_once (TYPE_BINFO (type), NULL, dfs_get_pure_virtuals, type); } /* Debug info for C++ classes can get very large; try to avoid emitting it everywhere. Note that this optimization wins even when the target supports BINCL (if only slightly), and reduces the amount of work for the linker. */ void maybe_suppress_debug_info (tree t) { if (write_symbols == NO_DEBUG) return; /* We might have set this earlier in cp_finish_decl. */ TYPE_DECL_SUPPRESS_DEBUG (TYPE_MAIN_DECL (t)) = 0; /* Always emit the information for each class every time. */ if (flag_emit_class_debug_always) return; /* If we already know how we're handling this class, handle debug info the same way. */ if (CLASSTYPE_INTERFACE_KNOWN (t)) { if (CLASSTYPE_INTERFACE_ONLY (t)) TYPE_DECL_SUPPRESS_DEBUG (TYPE_MAIN_DECL (t)) = 1; /* else don't set it. */ } /* If the class has a vtable, write out the debug info along with the vtable. */ else if (TYPE_CONTAINS_VPTR_P (t)) TYPE_DECL_SUPPRESS_DEBUG (TYPE_MAIN_DECL (t)) = 1; /* Otherwise, just emit the debug info normally. */ } /* Note that we want debugging information for a base class of a class whose vtable is being emitted. Normally, this would happen because calling the constructor for a derived class implies calling the constructors for all bases, which involve initializing the appropriate vptr with the vtable for the base class; but in the presence of optimization, this initialization may be optimized away, so we tell finish_vtable_vardecl that we want the debugging information anyway. */ static tree dfs_debug_mark (tree binfo, void * /*data*/) { tree t = BINFO_TYPE (binfo); if (CLASSTYPE_DEBUG_REQUESTED (t)) return dfs_skip_bases; CLASSTYPE_DEBUG_REQUESTED (t) = 1; return NULL_TREE; } /* Write out the debugging information for TYPE, whose vtable is being emitted. Also walk through our bases and note that we want to write out information for them. This avoids the problem of not writing any debug info for intermediate basetypes whose constructors, and thus the references to their vtables, and thus the vtables themselves, were optimized away. */ void note_debug_info_needed (tree type) { if (TYPE_DECL_SUPPRESS_DEBUG (TYPE_NAME (type))) { TYPE_DECL_SUPPRESS_DEBUG (TYPE_NAME (type)) = 0; rest_of_type_compilation (type, namespace_bindings_p ()); } dfs_walk_all (TYPE_BINFO (type), dfs_debug_mark, NULL, 0); } /* Helper for lookup_conversions_r. TO_TYPE is the type converted to by a conversion op in base BINFO. VIRTUAL_DEPTH is nonzero if BINFO is morally virtual, and VIRTUALNESS is nonzero if virtual bases have been encountered already in the tree walk. PARENT_CONVS is the list of lists of conversion functions that could hide CONV and OTHER_CONVS is the list of lists of conversion functions that could hide or be hidden by CONV, should virtualness be involved in the hierarchy. Merely checking the conversion op's name is not enough because two conversion operators to the same type can have different names. Return nonzero if we are visible. */ static int check_hidden_convs (tree binfo, int virtual_depth, int virtualness, tree to_type, tree parent_convs, tree other_convs) { tree level, probe; /* See if we are hidden by a parent conversion. */ for (level = parent_convs; level; level = TREE_CHAIN (level)) for (probe = TREE_VALUE (level); probe; probe = TREE_CHAIN (probe)) if (same_type_p (to_type, TREE_TYPE (probe))) return 0; if (virtual_depth || virtualness) { /* In a virtual hierarchy, we could be hidden, or could hide a conversion function on the other_convs list. */ for (level = other_convs; level; level = TREE_CHAIN (level)) { int we_hide_them; int they_hide_us; tree *prev, other; if (!(virtual_depth || TREE_STATIC (level))) /* Neither is morally virtual, so cannot hide each other. */ continue; if (!TREE_VALUE (level)) /* They evaporated away already. */ continue; they_hide_us = (virtual_depth && original_binfo (binfo, TREE_PURPOSE (level))); we_hide_them = (!they_hide_us && TREE_STATIC (level) && original_binfo (TREE_PURPOSE (level), binfo)); if (!(we_hide_them || they_hide_us)) /* Neither is within the other, so no hiding can occur. */ continue; for (prev = &TREE_VALUE (level), other = *prev; other;) { if (same_type_p (to_type, TREE_TYPE (other))) { if (they_hide_us) /* We are hidden. */ return 0; if (we_hide_them) { /* We hide the other one. */ other = TREE_CHAIN (other); *prev = other; continue; } } prev = &TREE_CHAIN (other); other = *prev; } } } return 1; } /* Helper for lookup_conversions_r. PARENT_CONVS is a list of lists of conversion functions, the first slot will be for the current binfo, if MY_CONVS is non-NULL. CHILD_CONVS is the list of lists of conversion functions from children of the current binfo, concatenated with conversions from elsewhere in the hierarchy -- that list begins with OTHER_CONVS. Return a single list of lists containing only conversions from the current binfo and its children. */ static tree split_conversions (tree my_convs, tree parent_convs, tree child_convs, tree other_convs) { tree t; tree prev; /* Remove the original other_convs portion from child_convs. */ for (prev = NULL, t = child_convs; t != other_convs; prev = t, t = TREE_CHAIN (t)) continue; if (prev) TREE_CHAIN (prev) = NULL_TREE; else child_convs = NULL_TREE; /* Attach the child convs to any we had at this level. */ if (my_convs) { my_convs = parent_convs; TREE_CHAIN (my_convs) = child_convs; } else my_convs = child_convs; return my_convs; } /* Worker for lookup_conversions. Lookup conversion functions in BINFO and its children. VIRTUAL_DEPTH is nonzero, if BINFO is in a morally virtual base, and VIRTUALNESS is nonzero, if we've encountered virtual bases already in the tree walk. PARENT_CONVS is a list of conversions within parent binfos. OTHER_CONVS are conversions found elsewhere in the tree. Return the conversions found within this portion of the graph in CONVS. Return nonzero if we encountered virtualness. We keep template and non-template conversions separate, to avoid unnecessary type comparisons. The located conversion functions are held in lists of lists. The TREE_VALUE of the outer list is the list of conversion functions found in a particular binfo. The TREE_PURPOSE of both the outer and inner lists is the binfo at which those conversions were found. TREE_STATIC is set for those lists within of morally virtual binfos. The TREE_VALUE of the inner list is the conversion function or overload itself. The TREE_TYPE of each inner list node is the converted-to type. */ static int lookup_conversions_r (tree binfo, int virtual_depth, int virtualness, tree parent_convs, tree other_convs, tree *convs) { int my_virtualness = 0; tree my_convs = NULL_TREE; tree child_convs = NULL_TREE; /* If we have no conversion operators, then don't look. */ if (!TYPE_HAS_CONVERSION (BINFO_TYPE (binfo))) { *convs = NULL_TREE; return 0; } if (BINFO_VIRTUAL_P (binfo)) virtual_depth++; /* First, locate the unhidden ones at this level. */ if (tree conv = get_class_binding (BINFO_TYPE (binfo), conv_op_identifier)) for (ovl_iterator iter (conv); iter; ++iter) { tree fn = *iter; tree type = DECL_CONV_FN_TYPE (fn); if (TREE_CODE (fn) != TEMPLATE_DECL && type_uses_auto (type)) { mark_used (fn); type = DECL_CONV_FN_TYPE (fn); } if (check_hidden_convs (binfo, virtual_depth, virtualness, type, parent_convs, other_convs)) { my_convs = tree_cons (binfo, fn, my_convs); TREE_TYPE (my_convs) = type; if (virtual_depth) { TREE_STATIC (my_convs) = 1; my_virtualness = 1; } } } if (my_convs) { parent_convs = tree_cons (binfo, my_convs, parent_convs); if (virtual_depth) TREE_STATIC (parent_convs) = 1; } child_convs = other_convs; /* Now iterate over each base, looking for more conversions. */ unsigned i; tree base_binfo; for (i = 0; BINFO_BASE_ITERATE (binfo, i, base_binfo); i++) { tree base_convs; unsigned base_virtualness; base_virtualness = lookup_conversions_r (base_binfo, virtual_depth, virtualness, parent_convs, child_convs, &base_convs); if (base_virtualness) my_virtualness = virtualness = 1; child_convs = chainon (base_convs, child_convs); } *convs = split_conversions (my_convs, parent_convs, child_convs, other_convs); return my_virtualness; } /* Return a TREE_LIST containing all the non-hidden user-defined conversion functions for TYPE (and its base-classes). The TREE_VALUE of each node is the FUNCTION_DECL of the conversion function. The TREE_PURPOSE is the BINFO from which the conversion functions in this node were selected. This function is effectively performing a set of member lookups as lookup_fnfield does, but using the type being converted to as the unique key, rather than the field name. */ tree lookup_conversions (tree type) { tree convs; complete_type (type); if (!CLASS_TYPE_P (type) || !TYPE_BINFO (type)) return NULL_TREE; lookup_conversions_r (TYPE_BINFO (type), 0, 0, NULL_TREE, NULL_TREE, &convs); tree list = NULL_TREE; /* Flatten the list-of-lists */ for (; convs; convs = TREE_CHAIN (convs)) { tree probe, next; for (probe = TREE_VALUE (convs); probe; probe = next) { next = TREE_CHAIN (probe); TREE_CHAIN (probe) = list; list = probe; } } return list; } /* Returns the binfo of the first direct or indirect virtual base derived from BINFO, or NULL if binfo is not via virtual. */ tree binfo_from_vbase (tree binfo) { for (; binfo; binfo = BINFO_INHERITANCE_CHAIN (binfo)) { if (BINFO_VIRTUAL_P (binfo)) return binfo; } return NULL_TREE; } /* Returns the binfo of the first direct or indirect virtual base derived from BINFO up to the TREE_TYPE, LIMIT, or NULL if binfo is not via virtual. */ tree binfo_via_virtual (tree binfo, tree limit) { if (limit && !CLASSTYPE_VBASECLASSES (limit)) /* LIMIT has no virtual bases, so BINFO cannot be via one. */ return NULL_TREE; for (; binfo && !SAME_BINFO_TYPE_P (BINFO_TYPE (binfo), limit); binfo = BINFO_INHERITANCE_CHAIN (binfo)) { if (BINFO_VIRTUAL_P (binfo)) return binfo; } return NULL_TREE; } /* BINFO is for a base class in some hierarchy. Return true iff it is a direct base. */ bool binfo_direct_p (tree binfo) { tree d_binfo = BINFO_INHERITANCE_CHAIN (binfo); if (BINFO_INHERITANCE_CHAIN (d_binfo)) /* A second inheritance chain means indirect. */ return false; if (!BINFO_VIRTUAL_P (binfo)) /* Non-virtual, so only one inheritance chain means direct. */ return true; /* A virtual base looks like a direct base, so we need to look through the direct bases to see if it's there. */ tree b_binfo; for (int i = 0; BINFO_BASE_ITERATE (d_binfo, i, b_binfo); ++i) if (b_binfo == binfo) return true; return false; } /* BINFO is a base binfo in the complete type BINFO_TYPE (HERE). Find the equivalent binfo within whatever graph HERE is located. This is the inverse of original_binfo. */ tree copied_binfo (tree binfo, tree here) { tree result = NULL_TREE; if (BINFO_VIRTUAL_P (binfo)) { tree t; for (t = here; BINFO_INHERITANCE_CHAIN (t); t = BINFO_INHERITANCE_CHAIN (t)) continue; result = binfo_for_vbase (BINFO_TYPE (binfo), BINFO_TYPE (t)); } else if (BINFO_INHERITANCE_CHAIN (binfo)) { tree cbinfo; tree base_binfo; int ix; cbinfo = copied_binfo (BINFO_INHERITANCE_CHAIN (binfo), here); for (ix = 0; BINFO_BASE_ITERATE (cbinfo, ix, base_binfo); ix++) if (SAME_BINFO_TYPE_P (BINFO_TYPE (base_binfo), BINFO_TYPE (binfo))) { result = base_binfo; break; } } else { gcc_assert (SAME_BINFO_TYPE_P (BINFO_TYPE (here), BINFO_TYPE (binfo))); result = here; } gcc_assert (result); return result; } tree binfo_for_vbase (tree base, tree t) { unsigned ix; tree binfo; vec *vbases; for (vbases = CLASSTYPE_VBASECLASSES (t), ix = 0; vec_safe_iterate (vbases, ix, &binfo); ix++) if (SAME_BINFO_TYPE_P (BINFO_TYPE (binfo), base)) return binfo; return NULL; } /* BINFO is some base binfo of HERE, within some other hierarchy. Return the equivalent binfo, but in the hierarchy dominated by HERE. This is the inverse of copied_binfo. If BINFO is not a base binfo of HERE, returns NULL_TREE. */ tree original_binfo (tree binfo, tree here) { tree result = NULL; if (SAME_BINFO_TYPE_P (BINFO_TYPE (binfo), BINFO_TYPE (here))) result = here; else if (BINFO_VIRTUAL_P (binfo)) result = (CLASSTYPE_VBASECLASSES (BINFO_TYPE (here)) ? binfo_for_vbase (BINFO_TYPE (binfo), BINFO_TYPE (here)) : NULL_TREE); else if (BINFO_INHERITANCE_CHAIN (binfo)) { tree base_binfos; base_binfos = original_binfo (BINFO_INHERITANCE_CHAIN (binfo), here); if (base_binfos) { int ix; tree base_binfo; for (ix = 0; (base_binfo = BINFO_BASE_BINFO (base_binfos, ix)); ix++) if (SAME_BINFO_TYPE_P (BINFO_TYPE (base_binfo), BINFO_TYPE (binfo))) { result = base_binfo; break; } } } return result; } /* True iff TYPE has any dependent bases (and therefore we can't say definitively that another class is not a base of an instantiation of TYPE). */ bool any_dependent_bases_p (tree type) { if (!type || !CLASS_TYPE_P (type) || !uses_template_parms (type)) return false; /* If we haven't set TYPE_BINFO yet, we don't know anything about the bases. Return false because in this situation we aren't actually looking up names in the scope of the class, so it doesn't matter whether it has dependent bases. */ if (!TYPE_BINFO (type)) return false; unsigned i; tree base_binfo; FOR_EACH_VEC_SAFE_ELT (BINFO_BASE_BINFOS (TYPE_BINFO (type)), i, base_binfo) if (BINFO_DEPENDENT_BASE_P (base_binfo)) return true; return false; }