/* Breadth-first and depth-first routines for searching multiple-inheritance lattice for GNU C++. Copyright (C) 1987, 89, 92-97, 1998, 1999 Free Software Foundation, Inc. Contributed by Michael Tiemann (tiemann@cygnus.com) This file is part of GNU CC. GNU CC 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 2, or (at your option) any later version. GNU CC 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 GNU CC; see the file COPYING. If not, write to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ /* High-level class interface. */ #include "config.h" #include "system.h" #include "tree.h" #include "cp-tree.h" #include "obstack.h" #include "flags.h" #include "rtl.h" #include "output.h" #include "toplev.h" #define obstack_chunk_alloc xmalloc #define obstack_chunk_free free extern struct obstack *current_obstack; #include "stack.h" /* Obstack used for remembering decision points of breadth-first. */ static struct obstack search_obstack; /* Methods for pushing and popping objects to and from obstacks. */ struct stack_level * push_stack_level (obstack, tp, size) struct obstack *obstack; char *tp; /* Sony NewsOS 5.0 compiler doesn't like void * here. */ int size; { struct stack_level *stack; obstack_grow (obstack, tp, size); stack = (struct stack_level *) ((char*)obstack_next_free (obstack) - size); obstack_finish (obstack); stack->obstack = obstack; stack->first = (tree *) obstack_base (obstack); stack->limit = obstack_room (obstack) / sizeof (tree *); return stack; } struct stack_level * pop_stack_level (stack) struct stack_level *stack; { struct stack_level *tem = stack; struct obstack *obstack = tem->obstack; stack = tem->prev; obstack_free (obstack, tem); return stack; } #define search_level stack_level static struct search_level *search_stack; static tree get_abstract_virtuals_1 PROTO((tree, int, tree)); static tree next_baselink PROTO((tree)); static tree get_vbase_1 PROTO((tree, tree, unsigned int *)); static tree convert_pointer_to_vbase PROTO((tree, tree)); static tree lookup_field_1 PROTO((tree, tree)); static tree convert_pointer_to_single_level PROTO((tree, tree)); static int lookup_fnfields_here PROTO((tree, tree)); static int is_subobject_of_p PROTO((tree, tree)); static int hides PROTO((tree, tree)); static tree virtual_context PROTO((tree, tree, tree)); static tree dfs_check_overlap PROTO((tree, void *)); static tree dfs_no_overlap_yet PROTO((tree, void *)); static int get_base_distance_recursive PROTO((tree, int, int, int, int *, tree *, tree, int, int *, int, int)); static int dynamic_cast_base_recurse PROTO((tree, tree, int, tree *)); static void expand_upcast_fixups PROTO((tree, tree, tree, tree, tree, tree, tree *)); static void fixup_virtual_upcast_offsets PROTO((tree, tree, int, int, tree, tree, tree, tree, tree *)); static tree unmarkedp PROTO((tree, void *)); static tree marked_vtable_pathp PROTO((tree, void *)); static tree unmarked_vtable_pathp PROTO((tree, void *)); static tree marked_new_vtablep PROTO((tree, void *)); static tree unmarked_new_vtablep PROTO((tree, void *)); static tree marked_pushdecls_p PROTO((tree, void *)); static tree unmarked_pushdecls_p PROTO((tree, void *)); #if 0 static tree dfs_debug_unmarkedp PROTO((tree, void *)); static tree dfs_debug_mark PROTO((tree, void *)); #endif static tree dfs_find_vbases PROTO((tree, void *)); static tree dfs_clear_vbase_slots PROTO((tree, void *)); static tree dfs_init_vbase_pointers PROTO((tree, void *)); static tree dfs_get_vbase_types PROTO((tree, void *)); static tree dfs_push_type_decls PROTO((tree, void *)); static tree dfs_push_decls PROTO((tree, void *)); static tree dfs_unuse_fields PROTO((tree, void *)); static tree add_conversions PROTO((tree, void *)); static tree get_virtuals_named_this PROTO((tree, tree)); static tree get_virtual_destructor PROTO((tree, void *)); static tree tree_has_any_destructor_p PROTO((tree, void *)); static int covariant_return_p PROTO((tree, tree)); static int check_final_overrider PROTO((tree, tree)); static struct search_level *push_search_level PROTO((struct stack_level *, struct obstack *)); static struct search_level *pop_search_level PROTO((struct stack_level *)); static tree bfs_walk PROTO((tree, tree (*) (tree, void *), tree (*) (tree, void *), void *)); static tree lookup_field_queue_p PROTO((tree, void *)); static tree lookup_field_r PROTO((tree, void *)); static tree dfs_walk_real PROTO ((tree, tree (*) (tree, void *), tree (*) (tree, void *), tree (*) (tree, void *), void *)); static tree get_virtuals_named_this_r PROTO ((tree, void *)); static tree context_for_name_lookup PROTO ((tree)); static tree canonical_binfo PROTO ((tree)); static tree shared_marked_p PROTO ((tree, void *)); static tree shared_unmarked_p PROTO ((tree, void *)); static int dependent_base_p PROTO ((tree)); static tree dfs_accessible_queue_p PROTO ((tree, void *)); static tree dfs_accessible_p PROTO ((tree, void *)); static tree dfs_access_in_type PROTO ((tree, void *)); static tree access_in_type PROTO ((tree, tree)); static tree dfs_canonical_queue PROTO ((tree, void *)); static tree dfs_assert_unmarked_p PROTO ((tree, void *)); static void assert_canonical_unmarked PROTO ((tree)); static int protected_accessible_p PROTO ((tree, tree, tree, tree)); static int friend_accessible_p PROTO ((tree, tree, tree, tree)); static void setup_class_bindings PROTO ((tree, int)); static int template_self_reference_p PROTO ((tree, tree)); static void fixup_all_virtual_upcast_offsets PROTO ((tree, tree)); /* Allocate a level of searching. */ static struct search_level * push_search_level (stack, obstack) struct stack_level *stack; struct obstack *obstack; { struct search_level tem; tem.prev = stack; return push_stack_level (obstack, (char *)&tem, sizeof (tem)); } /* Discard a level of search allocation. */ static struct search_level * pop_search_level (obstack) struct stack_level *obstack; { register struct search_level *stack = pop_stack_level (obstack); return stack; } /* Variables for gathering statistics. */ #ifdef GATHER_STATISTICS static int n_fields_searched; static int n_calls_lookup_field, n_calls_lookup_field_1; static int n_calls_lookup_fnfields, n_calls_lookup_fnfields_1; static int n_calls_get_base_type; static int n_outer_fields_searched; static int n_contexts_saved; #endif /* GATHER_STATISTICS */ /* Get a virtual binfo that is found inside BINFO's hierarchy that is the same type as the type given in PARENT. To be optimal, we want the first one that is found by going through the least number of virtual bases. This uses a clever algorithm that updates *depth when we find the vbase, and cuts off other paths of search when they reach that depth. */ static tree get_vbase_1 (parent, binfo, depth) tree parent, binfo; unsigned int *depth; { tree binfos; int i, n_baselinks; tree rval = NULL_TREE; if (BINFO_TYPE (binfo) == parent && TREE_VIA_VIRTUAL (binfo)) { *depth = 0; return binfo; } *depth = *depth - 1; binfos = BINFO_BASETYPES (binfo); n_baselinks = binfos ? TREE_VEC_LENGTH (binfos) : 0; /* Process base types. */ for (i = 0; i < n_baselinks; i++) { tree base_binfo = TREE_VEC_ELT (binfos, i); tree nrval; if (*depth == 0) break; nrval = get_vbase_1 (parent, base_binfo, depth); if (nrval) rval = nrval; } *depth = *depth+1; return rval; } /* Return the shortest path to vbase PARENT within BINFO, ignoring access and ambiguity. */ tree get_vbase (parent, binfo) tree parent; tree binfo; { unsigned int d = (unsigned int)-1; return get_vbase_1 (parent, binfo, &d); } /* Convert EXPR to a virtual base class of type TYPE. We know that EXPR is a non-null POINTER_TYPE to RECORD_TYPE. We also know that the type of what expr points to has a virtual base of type TYPE. */ static tree convert_pointer_to_vbase (type, expr) tree type; tree expr; { tree vb = get_vbase (type, TYPE_BINFO (TREE_TYPE (TREE_TYPE (expr)))); return convert_pointer_to_real (vb, expr); } /* Check whether the type given in BINFO is derived from PARENT. If it isn't, return 0. If it is, but the derivation is MI-ambiguous AND protect != 0, emit an error message and return error_mark_node. Otherwise, if TYPE is derived from PARENT, return the actual base information, unless a one of the protection violations below occurs, in which case emit an error message and return error_mark_node. If PROTECT is 1, then check if access to a public field of PARENT would be private. Also check for ambiguity. */ tree get_binfo (parent, binfo, protect) register tree parent, binfo; int protect; { tree type = NULL_TREE; int dist; tree rval = NULL_TREE; if (TREE_CODE (parent) == TREE_VEC) parent = BINFO_TYPE (parent); else if (! IS_AGGR_TYPE_CODE (TREE_CODE (parent))) my_friendly_abort (89); if (TREE_CODE (binfo) == TREE_VEC) type = BINFO_TYPE (binfo); else if (IS_AGGR_TYPE_CODE (TREE_CODE (binfo))) type = binfo; else my_friendly_abort (90); dist = get_base_distance (parent, binfo, protect, &rval); if (dist == -3) { cp_error ("fields of `%T' are inaccessible in `%T' due to private inheritance", parent, type); return error_mark_node; } else if (dist == -2 && protect) { cp_error ("type `%T' is ambiguous base class for type `%T'", parent, type); return error_mark_node; } return rval; } /* This is the newer depth first get_base_distance routine. */ static int get_base_distance_recursive (binfo, depth, is_private, rval, rval_private_ptr, new_binfo_ptr, parent, protect, via_virtual_ptr, via_virtual, current_scope_in_chain) tree binfo; int depth, is_private, rval; int *rval_private_ptr; tree *new_binfo_ptr, parent; int protect, *via_virtual_ptr, via_virtual; int current_scope_in_chain; { tree binfos; int i, n_baselinks; if (protect && !current_scope_in_chain && is_friend (BINFO_TYPE (binfo), current_scope ())) current_scope_in_chain = 1; if (BINFO_TYPE (binfo) == parent || binfo == parent) { int better = 0; if (rval == -1) /* This is the first time we've found parent. */ better = 1; else if (tree_int_cst_equal (BINFO_OFFSET (*new_binfo_ptr), BINFO_OFFSET (binfo)) && *via_virtual_ptr && via_virtual) { /* A new path to the same vbase. If this one has better access or is shorter, take it. */ if (protect) better = *rval_private_ptr - is_private; if (better == 0) better = rval - depth; } else { /* Ambiguous base class. */ rval = depth = -2; /* If we get an ambiguity between virtual and non-virtual base class, return the non-virtual in case we are ignoring ambiguity. */ better = *via_virtual_ptr - via_virtual; } if (better > 0) { rval = depth; *rval_private_ptr = is_private; *new_binfo_ptr = binfo; *via_virtual_ptr = via_virtual; } return rval; } binfos = BINFO_BASETYPES (binfo); n_baselinks = binfos ? TREE_VEC_LENGTH (binfos) : 0; depth += 1; /* Process base types. */ for (i = 0; i < n_baselinks; i++) { tree base_binfo = TREE_VEC_ELT (binfos, i); int via_private = (protect && (is_private || (!TREE_VIA_PUBLIC (base_binfo) && !(TREE_VIA_PROTECTED (base_binfo) && current_scope_in_chain) && !is_friend (BINFO_TYPE (binfo), current_scope ())))); int this_virtual = via_virtual || TREE_VIA_VIRTUAL (base_binfo); rval = get_base_distance_recursive (base_binfo, depth, via_private, rval, rval_private_ptr, new_binfo_ptr, parent, protect, via_virtual_ptr, this_virtual, current_scope_in_chain); /* If we've found a non-virtual, ambiguous base class, we don't need to keep searching. */ if (rval == -2 && *via_virtual_ptr == 0) return rval; } return rval; } /* Return the number of levels between type PARENT and the type given in BINFO, following the leftmost path to PARENT not found along a virtual path, if there are no real PARENTs (all come from virtual base classes), then follow the shortest public path to PARENT. Return -1 if TYPE is not derived from PARENT. Return -2 if PARENT is an ambiguous base class of TYPE, and PROTECT is non-negative. Return -3 if PARENT is private to TYPE, and PROTECT is non-zero. If PATH_PTR is non-NULL, then also build the list of types from PARENT to TYPE, with TREE_VIA_VIRTUAL and TREE_VIA_PUBLIC set. PARENT can also be a binfo, in which case that exact parent is found and no other. convert_pointer_to_real uses this functionality. If BINFO is a binfo, its BINFO_INHERITANCE_CHAIN will be left alone. */ int get_base_distance (parent, binfo, protect, path_ptr) register tree parent, binfo; int protect; tree *path_ptr; { int rval; int rval_private = 0; tree type = NULL_TREE; tree new_binfo = NULL_TREE; int via_virtual; int watch_access = protect; /* Should we be completing types here? */ if (TREE_CODE (parent) != TREE_VEC) parent = complete_type (TYPE_MAIN_VARIANT (parent)); else complete_type (TREE_TYPE (parent)); if (TREE_CODE (binfo) == TREE_VEC) type = BINFO_TYPE (binfo); else if (IS_AGGR_TYPE_CODE (TREE_CODE (binfo))) { type = complete_type (binfo); binfo = TYPE_BINFO (type); if (path_ptr) my_friendly_assert (BINFO_INHERITANCE_CHAIN (binfo) == NULL_TREE, 980827); } else my_friendly_abort (92); if (parent == type || parent == binfo) { /* If the distance is 0, then we don't really need a path pointer, but we shouldn't let garbage go back. */ if (path_ptr) *path_ptr = binfo; return 0; } if (path_ptr) watch_access = 1; rval = get_base_distance_recursive (binfo, 0, 0, -1, &rval_private, &new_binfo, parent, watch_access, &via_virtual, 0, 0); /* Access restrictions don't count if we found an ambiguous basetype. */ if (rval == -2 && protect >= 0) rval_private = 0; if (rval && protect && rval_private) return -3; /* If they gave us the real vbase binfo, which isn't in the main binfo tree, deal with it. This happens when we are called from expand_upcast_fixups. */ if (rval == -1 && TREE_CODE (parent) == TREE_VEC && parent == binfo_member (BINFO_TYPE (parent), CLASSTYPE_VBASECLASSES (type))) { my_friendly_assert (BINFO_INHERITANCE_CHAIN (parent) == binfo, 980827); new_binfo = parent; rval = 1; } if (path_ptr) *path_ptr = new_binfo; return rval; } /* Worker function for get_dynamic_cast_base_type. */ static int dynamic_cast_base_recurse (subtype, binfo, via_virtual, offset_ptr) tree subtype; tree binfo; int via_virtual; tree *offset_ptr; { tree binfos; int i, n_baselinks; int worst = -3; if (BINFO_TYPE (binfo) == subtype) { if (via_virtual) return -2; else { *offset_ptr = BINFO_OFFSET (binfo); return 0; } } binfos = BINFO_BASETYPES (binfo); n_baselinks = binfos ? TREE_VEC_LENGTH (binfos) : 0; for (i = 0; i < n_baselinks; i++) { tree base_binfo = TREE_VEC_ELT (binfos, i); int rval; if (!TREE_VIA_PUBLIC (base_binfo)) continue; rval = dynamic_cast_base_recurse (subtype, base_binfo, via_virtual || TREE_VIA_VIRTUAL (base_binfo), offset_ptr); if (worst == -3) worst = rval; else if (rval >= 0) worst = worst >= 0 ? -1 : worst; else if (rval > -3) worst = worst < rval ? worst : rval; } return worst; } /* 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 independant 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 non-virtual bases. BOFF == -2, SUBTYPE occurs as multiple public virtual or non-virtual bases. BOFF == -3, SUBTYPE is not a public base. */ tree get_dynamic_cast_base_type (subtype, target) tree subtype; tree target; { tree offset = NULL_TREE; int boff = dynamic_cast_base_recurse (subtype, TYPE_BINFO (target), 0, &offset); if (!boff) return offset; return build_int_2 (boff, -1); } /* 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 the FIELD_DECL. */ /* Do a 1-level search for NAME as a member of TYPE. The caller must figure out whether it can access this field. (Since it is only one level, this is reasonable.) */ static tree lookup_field_1 (type, name) tree type, name; { register tree field; if (TREE_CODE (type) == TEMPLATE_TYPE_PARM || TREE_CODE (type) == TEMPLATE_TEMPLATE_PARM) /* The TYPE_FIELDS of a TEMPLATE_TYPE_PARM are not fields at all; instead TYPE_FIELDS is the TEMPLATE_PARM_INDEX. (Miraculously, the code often worked even when we treated the index as a list of fields!) */ return NULL_TREE; if (TYPE_NAME (type) && DECL_LANG_SPECIFIC (TYPE_NAME (type)) && DECL_SORTED_FIELDS (TYPE_NAME (type))) { tree *fields = &TREE_VEC_ELT (DECL_SORTED_FIELDS (TYPE_NAME (type)), 0); int lo = 0, hi = TREE_VEC_LENGTH (DECL_SORTED_FIELDS (TYPE_NAME (type))); int i; while (lo < hi) { i = (lo + hi) / 2; #ifdef GATHER_STATISTICS n_fields_searched++; #endif /* GATHER_STATISTICS */ if (DECL_NAME (fields[i]) > name) hi = i; else if (DECL_NAME (fields[i]) < name) lo = i + 1; else return fields[i]; } return NULL_TREE; } field = TYPE_FIELDS (type); #ifdef GATHER_STATISTICS n_calls_lookup_field_1++; #endif /* GATHER_STATISTICS */ while (field) { #ifdef GATHER_STATISTICS n_fields_searched++; #endif /* GATHER_STATISTICS */ my_friendly_assert (TREE_CODE_CLASS (TREE_CODE (field)) == 'd', 0); if (DECL_NAME (field) == NULL_TREE && ANON_AGGR_TYPE_P (TREE_TYPE (field))) { tree temp = lookup_field_1 (TREE_TYPE (field), name); if (temp) return temp; } if (TREE_CODE (field) == USING_DECL) /* For now, we're just treating member using declarations as old ARM-style access declarations. Thus, there's no reason to return a USING_DECL, and the rest of the compiler can't handle it. Once the class is defined, these are purged from TYPE_FIELDS anyhow; see handle_using_decl. */ ; else if (DECL_NAME (field) == name) { if ((TREE_CODE(field) == VAR_DECL || TREE_CODE(field) == CONST_DECL) && DECL_ASSEMBLER_NAME (field) != NULL) GNU_xref_ref(current_function_decl, IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (field))); return field; } field = TREE_CHAIN (field); } /* Not found. */ if (name == vptr_identifier) { /* Give the user what s/he thinks s/he wants. */ if (TYPE_POLYMORPHIC_P (type)) return TYPE_VFIELD (type); } return NULL_TREE; } /* 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. */ tree current_scope () { if (current_function_decl == NULL_TREE) return current_class_type; if (current_class_type == NULL_TREE) return current_function_decl; if (DECL_CLASS_CONTEXT (current_function_decl) == current_class_type) return current_function_decl; return current_class_type; } /* Returns non-zero 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 () { tree cs = current_scope (); return cs && TREE_CODE (cs) == FUNCTION_DECL; } /* Return the scope of DECL, as appropriate when doing name-lookup. */ static tree context_for_name_lookup (decl) 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 teh anonymous union is declared. */ tree context = DECL_REAL_CONTEXT (decl); while (TYPE_P (context) && ANON_AGGR_TYPE_P (context)) context = TYPE_CONTEXT (context); if (!context) context = global_namespace; return context; } /* Return a canonical BINFO if BINFO is a virtual base, or just BINFO otherwise. */ static tree canonical_binfo (binfo) tree binfo; { return (TREE_VIA_VIRTUAL (binfo) ? TYPE_BINFO (BINFO_TYPE (binfo)) : binfo); } /* A queue function that simply ensures that we walk into the canonical versions of virtual bases. */ static tree dfs_canonical_queue (binfo, data) tree binfo; void *data ATTRIBUTE_UNUSED; { return canonical_binfo (binfo); } /* Called via dfs_walk from assert_canonical_unmarked. */ static tree dfs_assert_unmarked_p (binfo, data) tree binfo; void *data ATTRIBUTE_UNUSED; { my_friendly_assert (!BINFO_MARKED (binfo), 0); return NULL_TREE; } /* Asserts that all the nodes below BINFO (using the canonical versions of virtual bases) are unmarked. */ static void assert_canonical_unmarked (binfo) tree binfo; { dfs_walk (binfo, dfs_assert_unmarked_p, dfs_canonical_queue, 0); } /* If BINFO is marked, return a canonical version of BINFO. Otherwise, return NULL_TREE. */ static tree shared_marked_p (binfo, data) tree binfo; void *data; { binfo = canonical_binfo (binfo); return markedp (binfo, data) ? binfo : NULL_TREE; } /* If BINFO is not marked, return a canonical version of BINFO. Otherwise, return NULL_TREE. */ static tree shared_unmarked_p (binfo, data) tree binfo; void *data; { binfo = canonical_binfo (binfo); return unmarkedp (binfo, data) ? binfo : NULL_TREE; } /* 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 (binfo, data) tree binfo; void *data; { tree decl = (tree) data; tree type = BINFO_TYPE (binfo); tree access = NULL_TREE; if (context_for_name_lookup (decl) == type) { /* If we have desceneded to the scope of DECL, just note the appropriate access. */ if (TREE_PRIVATE (decl)) access = access_private_node; else if (TREE_PROTECTED (decl)) access = access_protected_node; else access = access_public_node; } else { /* First, check for an access-declaration that gives us more access to the DECL. The CONST_DECL for an enumeration constant will not have DECL_LANG_SPECIFIC, and thus no DECL_ACCESS. */ if (DECL_LANG_SPECIFIC (decl)) { access = purpose_member (type, DECL_ACCESS (decl)); if (access) access = TREE_VALUE (access); } if (!access) { int i; int n_baselinks; tree binfos; /* Otherwise, scan our baseclasses, and pick the most favorable access. */ binfos = BINFO_BASETYPES (binfo); n_baselinks = binfos ? TREE_VEC_LENGTH (binfos) : 0; for (i = 0; i < n_baselinks; ++i) { tree base_binfo = TREE_VEC_ELT (binfos, i); tree base_access = TREE_CHAIN (canonical_binfo (base_binfo)); if (!base_access || base_access == access_private_node) /* If it was not accessible in the base, or only accessible as a private member, we can't access it all. */ base_access = NULL_TREE; else if (TREE_VIA_PROTECTED (base_binfo)) /* Public and protected members in the base are protected here. */ base_access = access_protected_node; else if (!TREE_VIA_PUBLIC (base_binfo)) /* Public and protected members in the base are private here. */ base_access = access_private_node; /* See if the new access, via this base, gives more access than our previous best access. */ if (base_access && (base_access == access_public_node || (base_access == access_protected_node && access != access_public_node) || (base_access == access_private_node && !access))) { access = base_access; /* If the new access is public, we can't do better. */ if (access == access_public_node) break; } } } } /* Note the access to DECL in TYPE. */ TREE_CHAIN (binfo) = access; /* Mark TYPE as visited so that if we reach it again we do not duplicate our efforts here. */ SET_BINFO_MARKED (binfo); return NULL_TREE; } /* Return the access to DECL in TYPE. */ static tree access_in_type (type, decl) 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_real (binfo, 0, dfs_access_in_type, shared_unmarked_p, decl); dfs_walk (binfo, dfs_unmark, shared_marked_p, 0); assert_canonical_unmarked (binfo); return TREE_CHAIN (binfo); } /* Called from dfs_accessible_p via dfs_walk. */ static tree dfs_accessible_queue_p (binfo, data) tree binfo; void *data ATTRIBUTE_UNUSED; { if (BINFO_MARKED (binfo)) return NULL_TREE; /* If this class is inherited via private or protected inheritance, then we can't see it, unless we are a friend of the subclass. */ if (!TREE_VIA_PUBLIC (binfo) && !is_friend (BINFO_TYPE (BINFO_INHERITANCE_CHAIN (binfo)), current_scope ())) return NULL_TREE; return canonical_binfo (binfo); } /* Called from dfs_accessible_p via dfs_walk. */ static tree dfs_accessible_p (binfo, data) tree binfo; void *data; { int protected_ok = data != 0; tree access; /* We marked the binfos while computing the access in each type. So, we unmark as we go now. */ SET_BINFO_MARKED (binfo); access = TREE_CHAIN (binfo); if (access == access_public_node || (access == access_protected_node && protected_ok)) return binfo; else if (access && is_friend (BINFO_TYPE (binfo), current_scope ())) return binfo; return NULL_TREE; } /* Returns non-zero if it is OK to access DECL when named in TYPE through an object indiated by BINFO in the context of DERIVED. */ static int protected_accessible_p (type, decl, derived, binfo) tree type; tree decl; tree derived; tree binfo; { tree access; /* 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 private or protected. If DERIVED isn't derived from TYPE, then it certainly does not apply. */ if (!DERIVED_FROM_P (type, derived)) return 0; access = access_in_type (derived, decl); if (same_type_p (derived, type)) { if (access != access_private_node) return 0; } else if (access != access_private_node && access != access_protected_node) return 0; /* [class.protected] When a friend or a member function of a derived class references a protected nonstatic member of a base class, an access check applies in addition to those described earlier in clause _class.access_.4) 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)) { /* We can tell through what the reference is occurring by chasing BINFO up to the root. */ tree t = binfo; while (BINFO_INHERITANCE_CHAIN (t)) t = BINFO_INHERITANCE_CHAIN (t); if (!DERIVED_FROM_P (derived, BINFO_TYPE (t))) return 0; } return 1; } /* Returns non-zero if SCOPE is a friend of a type which would be able to acces DECL, named in TYPE, through the object indicated by BINFO. */ static int friend_accessible_p (scope, type, decl, binfo) tree scope; tree type; tree decl; tree binfo; { tree befriending_classes; tree t; if (!scope) return 0; if (TREE_CODE (scope) == FUNCTION_DECL || DECL_FUNCTION_TEMPLATE_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 (type, decl, TREE_VALUE (t), binfo)) return 1; if (TREE_CODE (scope) == FUNCTION_DECL || DECL_FUNCTION_TEMPLATE_P (scope)) { /* Perhaps this SCOPE is a member of a class which is a friend. */ if (friend_accessible_p (DECL_CLASS_CONTEXT (scope), type, decl, binfo)) return 1; /* Or an instantiation of something which is a friend. */ if (DECL_TEMPLATE_INFO (scope)) return friend_accessible_p (DECL_TI_TEMPLATE (scope), type, decl, binfo); } else if (CLASSTYPE_TEMPLATE_INFO (scope)) return friend_accessible_p (CLASSTYPE_TI_TEMPLATE (scope), type, decl, binfo); return 0; } /* DECL is a declaration from a base class of TYPE, which was the classs used to name DECL. Return non-zero 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. */ int accessible_p (type, decl) tree type; tree decl; { tree binfo; tree t; /* Non-zero if it's OK to access DECL if it has protected accessibility in TYPE. */ int protected_ok = 0; /* If we're not checking access, everything is accessible. */ if (!flag_access_control) return 1; /* 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; /* We don't do access control for types yet. */ if (TREE_CODE (decl) == TYPE_DECL) return 1; if (!TYPE_P (type)) { binfo = type; type = BINFO_TYPE (type); } else binfo = TYPE_BINFO (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 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. */ /* Figure out where the reference is occurring. Check to see if DECL is private or protected in this scope, since that will determine whether protected access in TYPE allowed. */ if (current_class_type) protected_ok = protected_accessible_p (type, decl, current_class_type, binfo); /* Now, loop through the classes of which we are a friend. */ if (!protected_ok) protected_ok = friend_accessible_p (current_scope (), type, decl, binfo); /* Standardize on the same that will access_in_type will use. We don't need to know what path was chosen from this point onwards. */ binfo = TYPE_BINFO (type); /* Compute the accessibility of DECL in the class hierarchy dominated by type. */ access_in_type (type, decl); /* Walk the hierarchy again, looking for a base class that allows access. */ t = dfs_walk (binfo, dfs_accessible_p, dfs_accessible_queue_p, protected_ok ? &protected_ok : 0); /* Clear any mark bits. Note that we have to walk the whole tree here, since we have aborted the previous walk from some point deep in the tree. */ dfs_walk (binfo, dfs_unmark, dfs_canonical_queue, 0); assert_canonical_unmarked (binfo); return t != NULL_TREE; } /* 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. This routine relies upon binfos not being shared, except for binfos for virtual bases. */ static int is_subobject_of_p (parent, binfo) tree parent, binfo; { tree binfos; int i, n_baselinks; /* We want to canonicalize for comparison purposes. But, when we iterate through basetypes later, we want the binfos from the original hierarchy. That's why we have to calculate BINFOS first, and then canonicalize. */ binfos = BINFO_BASETYPES (binfo); parent = canonical_binfo (parent); binfo = canonical_binfo (binfo); if (parent == binfo) return 1; n_baselinks = binfos ? TREE_VEC_LENGTH (binfos) : 0; /* Process and/or queue base types. */ for (i = 0; i < n_baselinks; i++) { tree base_binfo = TREE_VEC_ELT (binfos, i); if (!CLASS_TYPE_P (TREE_TYPE (base_binfo))) /* If we see a TEMPLATE_TYPE_PARM, or some such, as a base class there's no way to descend into it. */ continue; if (is_subobject_of_p (parent, base_binfo)) return 1; } return 0; } /* See if a one FIELD_DECL hides another. This routine is meant to correspond to ANSI working paper Sept 17, 1992 10p4. The two binfos given are the binfos corresponding to the particular places the FIELD_DECLs are found. This routine relies upon binfos not being shared, except for virtual bases. */ static int hides (hider_binfo, hidee_binfo) tree hider_binfo, hidee_binfo; { /* hider hides hidee, if hider has hidee as a base class and the instance of hidee is a sub-object of hider. The first part is always true is the second part is true. When hider and hidee are the same (two ways to get to the exact same member) we consider either one as hiding the other. */ return is_subobject_of_p (hidee_binfo, hider_binfo); } /* Very similar to lookup_fnfields_1 but it ensures that at least one function was declared inside the class given by TYPE. It really should only return functions that match the given TYPE. */ static int lookup_fnfields_here (type, name) tree type, name; { int idx = lookup_fnfields_1 (type, name); tree fndecls; /* ctors and dtors are always only in the right class. */ if (idx <= 1) return idx; fndecls = TREE_VEC_ELT (CLASSTYPE_METHOD_VEC (type), idx); while (fndecls) { if (TYPE_MAIN_VARIANT (DECL_CLASS_CONTEXT (OVL_CURRENT (fndecls))) == TYPE_MAIN_VARIANT (type)) return idx; fndecls = OVL_CHAIN (fndecls); } return -1; } 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 non-zero, we are looking for types, not data members. */ int want_type; /* If non-zero, RVAL was found by looking through a dependent base. */ int from_dep_base_p; /* If something went wrong, a message indicating what. */ const char *errstr; }; /* Returns non-zero if BINFO is not hidden by the value found by the lookup so far. If BINFO is hidden, then there's no need to look in it. DATA is really a struct lookup_field_info. Called from lookup_field via breadth_first_search. */ static tree lookup_field_queue_p (binfo, data) tree binfo; void *data; { struct lookup_field_info *lfi = (struct lookup_field_info *) data; /* Don't look for constructors or destructors in base classes. */ if (lfi->name == ctor_identifier || lfi->name == dtor_identifier) return NULL_TREE; /* If this base class is hidden by the best-known value so far, we don't need to look. */ if (!lfi->from_dep_base_p && lfi->rval_binfo && hides (lfi->rval_binfo, binfo)) return NULL_TREE; if (TREE_VIA_VIRTUAL (binfo)) return binfo_member (BINFO_TYPE (binfo), CLASSTYPE_VBASECLASSES (lfi->type)); else return binfo; } /* Within the scope of a template class, you can refer to the to the current specialization with the name of the template itself. For example: template struct S { S* sp; } Returns non-zero if DECL is such a declaration in a class TYPE. */ static int template_self_reference_p (type, decl) tree type; tree decl; { return (CLASSTYPE_USE_TEMPLATE (type) && PRIMARY_TEMPLATE_P (CLASSTYPE_TI_TEMPLATE (type)) && TREE_CODE (decl) == TYPE_DECL && DECL_ARTIFICIAL (decl) && DECL_NAME (decl) == constructor_name (type)); } /* 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 (binfo, data) tree binfo; void *data; { struct lookup_field_info *lfi = (struct lookup_field_info *) data; tree type = BINFO_TYPE (binfo); tree nval = NULL_TREE; int from_dep_base_p; /* First, look for a function. There can't be a function and a data member with the same name, and if there's a function and a type with the same name, the type is hidden by the function. */ if (!lfi->want_type) { int idx = lookup_fnfields_here (type, lfi->name); if (idx >= 0) nval = TREE_VEC_ELT (CLASSTYPE_METHOD_VEC (type), idx); } if (!nval) /* Look for a data member or type. */ nval = lookup_field_1 (type, lfi->name); /* If there is no declaration with the indicated name in this type, then there's nothing to do. */ if (!nval) return NULL_TREE; /* If we're looking up a type (as with an elaborated type specifier) we ignore all non-types we find. */ if (lfi->want_type && TREE_CODE (nval) != TYPE_DECL) { nval = purpose_member (lfi->name, CLASSTYPE_TAGS (type)); if (nval) nval = TYPE_MAIN_DECL (TREE_VALUE (nval)); else return NULL_TREE; } /* You must name a template base class with a template-id. */ if (!same_type_p (type, lfi->type) && template_self_reference_p (type, nval)) return NULL_TREE; from_dep_base_p = dependent_base_p (binfo); if (lfi->from_dep_base_p && !from_dep_base_p) { /* If the new declaration is not found via a dependent base, and the old one was, then we must prefer the new one. We weren't really supposed to be able to find the old one, so we don't want to be affected by a specialization. Consider: struct B { typedef int I; }; template struct D1 : virtual public B {}; template struct D : public D1, virtual pubic B { I i; }; The `I' in `D' is unambigousuly `B::I', regardless of how D1 is specialized. */ lfi->from_dep_base_p = 0; lfi->rval = NULL_TREE; lfi->rval_binfo = NULL_TREE; lfi->ambiguous = NULL_TREE; lfi->errstr = 0; } else if (lfi->rval_binfo && !lfi->from_dep_base_p && from_dep_base_p) /* Similarly, if the old declaration was not found via a dependent base, and the new one is, ignore the new one. */ return NULL_TREE; /* 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 && !hides (binfo, lfi->rval_binfo)) { if (nval == lfi->rval && SHARED_MEMBER_P (nval)) /* The two things are really the same. */ ; else if (hides (lfi->rval_binfo, 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. */ lfi->ambiguous = tree_cons (NULL_TREE, nval, lfi->ambiguous); TREE_TYPE (lfi->ambiguous) = error_mark_node; lfi->errstr = "request for member `%D' is ambiguous"; } } else { /* If the thing we're looking for is a virtual base class, then we know we've got what we want at this point; there's no way to get an ambiguity. */ if (VBASE_NAME_P (lfi->name)) { lfi->rval = nval; return nval; } if (from_dep_base_p && TREE_CODE (nval) != TYPE_DECL /* We need to return a member template class so we can define partial specializations. Is there a better way? */ && !DECL_CLASS_TEMPLATE_P (nval)) /* The thing we're looking for isn't a type, so the implicit typename extension doesn't apply, so we just pretend we didn't find anything. */ return NULL_TREE; lfi->rval = nval; lfi->from_dep_base_p = from_dep_base_p; lfi->rval_binfo = binfo; } return NULL_TREE; } /* Look for a memer named NAME in an inheritance lattice dominated by XBASETYPE. 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 an error message. If PROTECT is 2, we return a TREE_LIST whose TREEE_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 no TYPE_DECL can be found return NULL_TREE. */ tree lookup_member (xbasetype, name, protect, want_type) register tree xbasetype, name; int protect, want_type; { 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. */ const char *errstr = 0; if (xbasetype == current_class_type && TYPE_BEING_DEFINED (xbasetype) && IDENTIFIER_CLASS_VALUE (name)) { tree field = IDENTIFIER_CLASS_VALUE (name); if (TREE_CODE (field) != FUNCTION_DECL && ! (want_type && TREE_CODE (field) != TYPE_DECL)) /* We're in the scope of this class, and the value has already been looked up. Just return the cached value. */ return field; } if (TREE_CODE (xbasetype) == TREE_VEC) { type = BINFO_TYPE (xbasetype); basetype_path = xbasetype; } else if (IS_AGGR_TYPE_CODE (TREE_CODE (xbasetype))) { type = xbasetype; basetype_path = TYPE_BINFO (type); my_friendly_assert (BINFO_INHERITANCE_CHAIN (basetype_path) == NULL_TREE, 980827); } else my_friendly_abort (97); complete_type (type); #ifdef GATHER_STATISTICS n_calls_lookup_field++; #endif /* GATHER_STATISTICS */ bzero ((PTR) &lfi, sizeof (lfi)); lfi.type = type; lfi.name = name; lfi.want_type = want_type; bfs_walk (basetype_path, &lookup_field_r, &lookup_field_queue_p, &lfi); rval = lfi.rval; rval_binfo = lfi.rval_binfo; if (rval_binfo) type = BINFO_TYPE (rval_binfo); errstr = lfi.errstr; /* If we are not interested in ambiguities, don't report them; just return NULL_TREE. */ if (!protect && lfi.ambiguous) return NULL_TREE; if (protect == 2) { if (lfi.ambiguous) return lfi.ambiguous; else protect = 0; } /* [class.access] In the case of overloaded function names, access control is applied to the function selected by overloaded resolution. */ if (rval && protect && !is_overloaded_fn (rval) && !enforce_access (xbasetype, rval)) return error_mark_node; if (errstr && protect) { cp_error (errstr, name, type); if (lfi.ambiguous) print_candidates (lfi.ambiguous); rval = error_mark_node; } /* If the thing we found was found via the implicit typename extension, build the typename type. */ if (rval && lfi.from_dep_base_p && !DECL_CLASS_TEMPLATE_P (rval)) rval = TYPE_STUB_DECL (build_typename_type (BINFO_TYPE (basetype_path), name, name, TREE_TYPE (rval))); if (rval && is_overloaded_fn (rval)) { rval = tree_cons (basetype_path, rval, NULL_TREE); SET_BASELINK_P (rval); } return rval; } /* Like lookup_member, except that if we find a function member we return NULL_TREE. */ tree lookup_field (xbasetype, name, protect, want_type) register tree xbasetype, name; int protect, want_type; { tree rval = lookup_member (xbasetype, name, protect, want_type); /* Ignore functions. */ if (rval && TREE_CODE (rval) == TREE_LIST) return NULL_TREE; return rval; } /* Like lookup_member, except that if we find a non-function member we return NULL_TREE. */ tree lookup_fnfields (xbasetype, name, protect) register tree xbasetype, name; int protect; { tree rval = lookup_member (xbasetype, name, protect, /*want_type=*/0); /* Ignore non-functions. */ if (rval && TREE_CODE (rval) != TREE_LIST) return NULL_TREE; return rval; } /* TYPE is a class type. Return the index of the fields within the method vector with name NAME, or -1 is no such field exists. */ int lookup_fnfields_1 (type, name) tree type, name; { tree method_vec = CLASS_TYPE_P (type) ? CLASSTYPE_METHOD_VEC (type) : NULL_TREE; if (method_vec != 0) { register int i; register tree *methods = &TREE_VEC_ELT (method_vec, 0); int len = TREE_VEC_LENGTH (method_vec); tree tmp; #ifdef GATHER_STATISTICS n_calls_lookup_fnfields_1++; #endif /* GATHER_STATISTICS */ /* Constructors are first... */ if (name == ctor_identifier) return methods[0] ? 0 : -1; /* and destructors are second. */ if (name == dtor_identifier) return methods[1] ? 1 : -1; for (i = 2; i < len && methods[i]; ++i) { #ifdef GATHER_STATISTICS n_outer_fields_searched++; #endif /* GATHER_STATISTICS */ tmp = OVL_CURRENT (methods[i]); if (DECL_NAME (tmp) == name) return i; /* If the type is complete and we're past the conversion ops, switch to binary search. */ if (! DECL_CONV_FN_P (tmp) && TYPE_SIZE (type)) { int lo = i + 1, hi = len; while (lo < hi) { i = (lo + hi) / 2; #ifdef GATHER_STATISTICS n_outer_fields_searched++; #endif /* GATHER_STATISTICS */ tmp = DECL_NAME (OVL_CURRENT (methods[i])); if (tmp > name) hi = i; else if (tmp < name) lo = i + 1; else return i; } break; } } /* If we didn't find it, it might have been a template conversion operator. (Note that we don't look for this case above so that we will always find specializations first.) */ if (IDENTIFIER_TYPENAME_P (name)) { for (i = 2; i < len && methods[i]; ++i) { tmp = OVL_CURRENT (methods[i]); if (! DECL_CONV_FN_P (tmp)) { /* Since all conversion operators come first, we know there is no such operator. */ break; } else if (TREE_CODE (tmp) == TEMPLATE_DECL) return i; } } } return -1; } /* Walk the class hierarchy dominated by TYPE. FN is called for each type in the hierarchy, in a breadth-first preorder traversal. . If it ever returns a non-NULL value, that value is immediately returned and the walk is terminated. At each node FN, is passed a BINFO indicating the path from the curently visited base-class to TYPE. The TREE_CHAINs of the BINFOs may be used for scratch space; they are otherwise unused. Before each base-class is walked QFN is called. If the value returned is non-zero, the base-class is walked; otherwise it is not. If QFN is NULL, it is treated as a function which always returns 1. Both FN and QFN are passed the DATA whenever they are called. */ static tree bfs_walk (binfo, fn, qfn, data) tree binfo; tree (*fn) PROTO((tree, void *)); tree (*qfn) PROTO((tree, void *)); void *data; { size_t head; size_t tail; tree rval = NULL_TREE; /* An array of the base classes of BINFO. These will be built up in breadth-first order, except where QFN prunes the search. */ varray_type bfs_bases; /* Start with enough room for ten base classes. That will be enough for most hierarchies. */ VARRAY_TREE_INIT (bfs_bases, 10, "search_stack"); /* Put the first type into the stack. */ VARRAY_TREE (bfs_bases, 0) = binfo; tail = 1; for (head = 0; head < tail; ++head) { int i; int n_baselinks; tree binfos; /* Pull the next type out of the queue. */ binfo = VARRAY_TREE (bfs_bases, head); /* If this is the one we're looking for, we're done. */ rval = (*fn) (binfo, data); if (rval) break; /* Queue up the base types. */ binfos = BINFO_BASETYPES (binfo); n_baselinks = binfos ? TREE_VEC_LENGTH (binfos): 0; for (i = 0; i < n_baselinks; i++) { tree base_binfo = TREE_VEC_ELT (binfos, i); if (qfn) base_binfo = (*qfn) (base_binfo, data); if (base_binfo) { if (tail == VARRAY_SIZE (bfs_bases)) VARRAY_GROW (bfs_bases, 2 * VARRAY_SIZE (bfs_bases)); VARRAY_TREE (bfs_bases, tail) = base_binfo; ++tail; } } } /* Clean up. */ VARRAY_FREE (bfs_bases); return rval; } /* Exactly like bfs_walk, except that a depth-first traversal is performed, and PREFN is called in preorder, while POSTFN is called in postorder. */ static tree dfs_walk_real (binfo, prefn, postfn, qfn, data) tree binfo; tree (*prefn) PROTO((tree, void *)); tree (*postfn) PROTO((tree, void *)); tree (*qfn) PROTO((tree, void *)); void *data; { int i; int n_baselinks; tree binfos; tree rval = NULL_TREE; /* Call the pre-order walking function. */ if (prefn) { rval = (*prefn) (binfo, data); if (rval) return rval; } /* Process the basetypes. */ binfos = BINFO_BASETYPES (binfo); n_baselinks = binfos ? TREE_VEC_LENGTH (binfos): 0; for (i = 0; i < n_baselinks; i++) { tree base_binfo = TREE_VEC_ELT (binfos, i); if (qfn) base_binfo = (*qfn) (base_binfo, data); if (base_binfo) { rval = dfs_walk_real (base_binfo, prefn, postfn, qfn, data); if (rval) return rval; } } /* Call the post-order walking function. */ if (postfn) rval = (*postfn) (binfo, data); return rval; } /* Exactly like bfs_walk, except that a depth-first post-order traversal is performed. */ tree dfs_walk (binfo, fn, qfn, data) tree binfo; tree (*fn) PROTO((tree, void *)); tree (*qfn) PROTO((tree, void *)); void *data; { return dfs_walk_real (binfo, 0, fn, qfn, data); } struct gvnt_info { /* The name of the function we are looking for. */ tree name; /* The overloaded functions we have found. */ tree fields; }; /* Called from get_virtuals_named_this via bfs_walk. */ static tree get_virtuals_named_this_r (binfo, data) tree binfo; void *data; { struct gvnt_info *gvnti = (struct gvnt_info *) data; tree type = BINFO_TYPE (binfo); int idx; idx = lookup_fnfields_here (BINFO_TYPE (binfo), gvnti->name); if (idx >= 0) gvnti->fields = tree_cons (binfo, TREE_VEC_ELT (CLASSTYPE_METHOD_VEC (type), idx), gvnti->fields); return NULL_TREE; } /* Return the virtual functions with the indicated NAME in the type indicated by BINFO. The result is a TREE_LIST whose TREE_PURPOSE indicates the base class from which the TREE_VALUE (an OVERLOAD or just a FUNCTION_DECL) originated. */ static tree get_virtuals_named_this (binfo, name) tree binfo; tree name; { struct gvnt_info gvnti; tree fields; gvnti.name = name; gvnti.fields = NULL_TREE; bfs_walk (binfo, get_virtuals_named_this_r, 0, &gvnti); /* Get to the function decls, and return the first virtual function with this name, if there is one. */ for (fields = gvnti.fields; fields; fields = next_baselink (fields)) { tree fndecl; for (fndecl = TREE_VALUE (fields); fndecl; fndecl = OVL_NEXT (fndecl)) if (DECL_VINDEX (OVL_CURRENT (fndecl))) return fields; } return NULL_TREE; } static tree get_virtual_destructor (binfo, data) tree binfo; void *data ATTRIBUTE_UNUSED; { tree type = BINFO_TYPE (binfo); if (TYPE_HAS_DESTRUCTOR (type) && DECL_VINDEX (TREE_VEC_ELT (CLASSTYPE_METHOD_VEC (type), 1))) return TREE_VEC_ELT (CLASSTYPE_METHOD_VEC (type), 1); return 0; } static tree tree_has_any_destructor_p (binfo, data) tree binfo; void *data ATTRIBUTE_UNUSED; { tree type = BINFO_TYPE (binfo); return TYPE_NEEDS_DESTRUCTOR (type) ? binfo : NULL_TREE; } /* Returns > 0 if a function with type DRETTYPE overriding a function with type BRETTYPE is covariant, as defined in [class.virtual]. Returns 1 if trivial covariance, 2 if non-trivial (requiring runtime adjustment), or -1 if pedantically invalid covariance. */ static int covariant_return_p (brettype, drettype) tree brettype, drettype; { tree binfo; if (TREE_CODE (brettype) == FUNCTION_DECL || TREE_CODE (brettype) == THUNK_DECL) { brettype = TREE_TYPE (TREE_TYPE (brettype)); drettype = TREE_TYPE (TREE_TYPE (drettype)); } else if (TREE_CODE (brettype) == METHOD_TYPE) { brettype = TREE_TYPE (brettype); drettype = TREE_TYPE (drettype); } if (same_type_p (brettype, drettype)) return 0; if (! (TREE_CODE (brettype) == TREE_CODE (drettype) && (TREE_CODE (brettype) == POINTER_TYPE || TREE_CODE (brettype) == REFERENCE_TYPE) && TYPE_QUALS (brettype) == TYPE_QUALS (drettype))) return 0; if (! can_convert (brettype, drettype)) return 0; brettype = TREE_TYPE (brettype); drettype = TREE_TYPE (drettype); /* If not pedantic, allow any standard pointer conversion. */ if (! IS_AGGR_TYPE (drettype) || ! IS_AGGR_TYPE (brettype)) return -1; binfo = get_binfo (brettype, drettype, 1); /* If we get an error_mark_node from get_binfo, it already complained, so let's just succeed. */ if (binfo == error_mark_node) return 1; if (! BINFO_OFFSET_ZEROP (binfo) || TREE_VIA_VIRTUAL (binfo)) return 2; return 1; } /* Check that virtual overrider OVERRIDER is acceptable for base function BASEFN. Issue diagnostic, and return zero, if unacceptable. */ static int check_final_overrider (overrider, basefn) tree overrider, basefn; { tree over_type = TREE_TYPE (overrider); tree base_type = TREE_TYPE (basefn); tree over_return = TREE_TYPE (over_type); tree base_return = TREE_TYPE (base_type); tree over_throw = TYPE_RAISES_EXCEPTIONS (over_type); tree base_throw = TYPE_RAISES_EXCEPTIONS (base_type); int i; if (same_type_p (base_return, over_return)) /* OK */; else if ((i = covariant_return_p (base_return, over_return))) { if (i == 2) sorry ("adjusting pointers for covariant returns"); if (pedantic && i == -1) { cp_pedwarn_at ("invalid covariant return type for `virtual %#D'", overrider); cp_pedwarn_at (" overriding `virtual %#D' (must be pointer or reference to class)", basefn); } } else if (IS_AGGR_TYPE_2 (base_return, over_return) && same_or_base_type_p (base_return, over_return)) { cp_error_at ("invalid covariant return type for `virtual %#D'", overrider); cp_error_at (" overriding `virtual %#D' (must use pointer or reference)", basefn); return 0; } else if (IDENTIFIER_ERROR_LOCUS (DECL_ASSEMBLER_NAME (overrider)) == NULL_TREE) { cp_error_at ("conflicting return type specified for `virtual %#D'", overrider); cp_error_at (" overriding `virtual %#D'", basefn); SET_IDENTIFIER_ERROR_LOCUS (DECL_ASSEMBLER_NAME (overrider), DECL_CLASS_CONTEXT (overrider)); return 0; } /* Check throw specifier is subset. */ /* XXX At the moment, punt on an overriding artificial function. We don't generate its exception specifier, so can't check it properly. */ if (! DECL_ARTIFICIAL (overrider) && !comp_except_specs (base_throw, over_throw, 0)) { cp_error_at ("looser throw specifier for `virtual %#F'", overrider); cp_error_at (" overriding `virtual %#F'", basefn); return 0; } return 1; } /* Given a class type TYPE, and a function decl FNDECL, look for a virtual function in TYPE's hierarchy which FNDECL could match as a virtual function. It doesn't matter which one we find. DTORP is nonzero if we are looking for a destructor. Destructors need special treatment because they do not match by name. */ tree get_matching_virtual (binfo, fndecl, dtorp) tree binfo, fndecl; int dtorp; { tree tmp = NULL_TREE; if (TREE_CODE (fndecl) == TEMPLATE_DECL) /* In [temp.mem] we have: A specialization of a member function template does not override a virtual function from a base class. */ return NULL_TREE; /* Breadth first search routines start searching basetypes of TYPE, so we must perform first ply of search here. */ if (dtorp) return bfs_walk (binfo, get_virtual_destructor, tree_has_any_destructor_p, 0); else { tree drettype, dtypes, btypes, instptr_type; tree baselink, best = NULL_TREE; tree declarator = DECL_NAME (fndecl); if (IDENTIFIER_VIRTUAL_P (declarator) == 0) return NULL_TREE; baselink = get_virtuals_named_this (binfo, declarator); if (baselink == NULL_TREE) return NULL_TREE; drettype = TREE_TYPE (TREE_TYPE (fndecl)); dtypes = TYPE_ARG_TYPES (TREE_TYPE (fndecl)); if (DECL_STATIC_FUNCTION_P (fndecl)) instptr_type = NULL_TREE; else instptr_type = TREE_TYPE (TREE_VALUE (dtypes)); for (; baselink; baselink = next_baselink (baselink)) { tree tmps; for (tmps = TREE_VALUE (baselink); tmps; tmps = OVL_NEXT (tmps)) { tmp = OVL_CURRENT (tmps); if (! DECL_VINDEX (tmp)) continue; btypes = TYPE_ARG_TYPES (TREE_TYPE (tmp)); if (instptr_type == NULL_TREE) { if (compparms (TREE_CHAIN (btypes), dtypes)) /* Caller knows to give error in this case. */ return tmp; return NULL_TREE; } if (/* The first parameter is the `this' parameter, which has POINTER_TYPE, and we can therefore safely use TYPE_QUALS, rather than CP_TYPE_QUALS. */ (TYPE_QUALS (TREE_TYPE (TREE_VALUE (btypes))) == TYPE_QUALS (instptr_type)) && compparms (TREE_CHAIN (btypes), TREE_CHAIN (dtypes))) { check_final_overrider (fndecl, tmp); /* FNDECL overrides this function. We continue to check all the other functions in order to catch errors; it might be that in some other baseclass a virtual function was declared with the same parameter types, but a different return type. */ best = tmp; } } } return best; } } /* Return the list of virtual functions which are abstract in type TYPE that come from non virtual base classes. See expand_direct_vtbls_init for the style of search we do. */ static tree get_abstract_virtuals_1 (binfo, do_self, abstract_virtuals) tree binfo; int do_self; tree abstract_virtuals; { tree binfos = BINFO_BASETYPES (binfo); int i, n_baselinks = binfos ? TREE_VEC_LENGTH (binfos) : 0; for (i = 0; i < n_baselinks; i++) { tree base_binfo = TREE_VEC_ELT (binfos, i); int is_not_base_vtable = i != CLASSTYPE_VFIELD_PARENT (BINFO_TYPE (binfo)); if (! TREE_VIA_VIRTUAL (base_binfo)) abstract_virtuals = get_abstract_virtuals_1 (base_binfo, is_not_base_vtable, abstract_virtuals); } /* Should we use something besides CLASSTYPE_VFIELDS? */ if (do_self && CLASSTYPE_VFIELDS (BINFO_TYPE (binfo))) { tree virtuals = BINFO_VIRTUALS (binfo); skip_rtti_stuff (&virtuals, BINFO_TYPE (binfo)); while (virtuals) { tree base_fndecl = TREE_VALUE (virtuals); if (DECL_ABSTRACT_VIRTUAL_P (base_fndecl)) abstract_virtuals = tree_cons (NULL_TREE, base_fndecl, abstract_virtuals); virtuals = TREE_CHAIN (virtuals); } } return abstract_virtuals; } /* Return the list of virtual functions which are abstract in type TYPE. This information is cached, and so must be built on a non-temporary obstack. */ tree get_abstract_virtuals (type) tree type; { tree vbases; tree abstract_virtuals = NULL; /* First get all from non-virtual bases. */ abstract_virtuals = get_abstract_virtuals_1 (TYPE_BINFO (type), 1, abstract_virtuals); for (vbases = CLASSTYPE_VBASECLASSES (type); vbases; vbases = TREE_CHAIN (vbases)) { tree virtuals = BINFO_VIRTUALS (vbases); skip_rtti_stuff (&virtuals, BINFO_TYPE (vbases)); while (virtuals) { tree base_fndecl = TREE_VALUE (virtuals); if (DECL_NEEDS_FINAL_OVERRIDER_P (base_fndecl)) cp_error ("`%#D' needs a final overrider", base_fndecl); else if (DECL_ABSTRACT_VIRTUAL_P (base_fndecl)) abstract_virtuals = tree_cons (NULL_TREE, base_fndecl, abstract_virtuals); virtuals = TREE_CHAIN (virtuals); } } return nreverse (abstract_virtuals); } static tree next_baselink (baselink) tree baselink; { tree tmp = TREE_TYPE (baselink); baselink = TREE_CHAIN (baselink); while (tmp) { /* @@ does not yet add previous base types. */ baselink = tree_cons (TREE_PURPOSE (tmp), TREE_VALUE (tmp), baselink); TREE_TYPE (baselink) = TREE_TYPE (tmp); tmp = TREE_CHAIN (tmp); } return baselink; } /* DEPTH-FIRST SEARCH ROUTINES. */ /* This routine converts a pointer to be a pointer of an immediate base class. The normal convert_pointer_to routine would diagnose the conversion as ambiguous, under MI code that has the base class as an ambiguous base class. */ static tree convert_pointer_to_single_level (to_type, expr) tree to_type, expr; { tree derived; tree binfo_of_derived; int i; derived = TREE_TYPE (TREE_TYPE (expr)); binfo_of_derived = TYPE_BINFO (derived); my_friendly_assert (BINFO_INHERITANCE_CHAIN (binfo_of_derived) == NULL_TREE, 980827); for (i = CLASSTYPE_N_BASECLASSES (derived) - 1; i >= 0; --i) { tree binfo = BINFO_BASETYPE (binfo_of_derived, i); my_friendly_assert (BINFO_INHERITANCE_CHAIN (binfo) == binfo_of_derived, 980827); if (same_type_p (BINFO_TYPE (binfo), to_type)) return build_vbase_path (PLUS_EXPR, build_pointer_type (to_type), expr, binfo, 1); } my_friendly_abort (19990607); /* NOTREACHED */ return NULL_TREE; } tree markedp (binfo, data) tree binfo; void *data ATTRIBUTE_UNUSED; { return BINFO_MARKED (binfo) ? binfo : NULL_TREE; } static tree unmarkedp (binfo, data) tree binfo; void *data ATTRIBUTE_UNUSED; { return !BINFO_MARKED (binfo) ? binfo : NULL_TREE; } static tree marked_vtable_pathp (binfo, data) tree binfo; void *data ATTRIBUTE_UNUSED; { return BINFO_VTABLE_PATH_MARKED (binfo) ? binfo : NULL_TREE; } static tree unmarked_vtable_pathp (binfo, data) tree binfo; void *data ATTRIBUTE_UNUSED; { return !BINFO_VTABLE_PATH_MARKED (binfo) ? binfo : NULL_TREE; } static tree marked_new_vtablep (binfo, data) tree binfo; void *data ATTRIBUTE_UNUSED; { return BINFO_NEW_VTABLE_MARKED (binfo) ? binfo : NULL_TREE; } static tree unmarked_new_vtablep (binfo, data) tree binfo; void *data ATTRIBUTE_UNUSED; { return !BINFO_NEW_VTABLE_MARKED (binfo) ? binfo : NULL_TREE; } static tree marked_pushdecls_p (binfo, data) tree binfo; void *data ATTRIBUTE_UNUSED; { return (CLASS_TYPE_P (BINFO_TYPE (binfo)) && BINFO_PUSHDECLS_MARKED (binfo)) ? binfo : NULL_TREE; } static tree unmarked_pushdecls_p (binfo, data) tree binfo; void *data ATTRIBUTE_UNUSED; { return (CLASS_TYPE_P (BINFO_TYPE (binfo)) && !BINFO_PUSHDECLS_MARKED (binfo)) ? binfo : NULL_TREE; } #if 0 static int dfs_search_slot_nonempty_p (binfo) tree binfo; { return CLASSTYPE_SEARCH_SLOT (BINFO_TYPE (binfo)) != 0; } static tree dfs_debug_unmarkedp (binfo, data) tree binfo; void *data ATTRIBUTE_UNUSED; { return (!CLASSTYPE_DEBUG_REQUESTED (BINFO_TYPE (binfo)) ? binfo : NULL_TREE); } #endif /* The worker functions for `dfs_walk'. These do not need to test anything (vis a vis marking) if they are paired with a predicate function (above). */ #if 0 static void dfs_mark (binfo) tree binfo; { SET_BINFO_MARKED (binfo); } #endif tree dfs_unmark (binfo, data) tree binfo; void *data ATTRIBUTE_UNUSED; { CLEAR_BINFO_MARKED (binfo); return NULL_TREE; } #if 0 static void dfs_mark_vtable_path (binfo) tree binfo; { SET_BINFO_VTABLE_PATH_MARKED (binfo); } static void dfs_unmark_vtable_path (binfo) tree binfo; { CLEAR_BINFO_VTABLE_PATH_MARKED (binfo); } static void dfs_mark_new_vtable (binfo) tree binfo; { SET_BINFO_NEW_VTABLE_MARKED (binfo); } static void dfs_unmark_new_vtable (binfo) tree binfo; { CLEAR_BINFO_NEW_VTABLE_MARKED (binfo); } static void dfs_clear_search_slot (binfo) tree binfo; { CLASSTYPE_SEARCH_SLOT (BINFO_TYPE (binfo)) = 0; } /* Keep this code around in case we later want to control debug info based on whether a type is "used". Currently, we only suppress debug info if we can emit it with the vtable. jason 1999-11-11) */ static tree dfs_debug_mark (binfo, data) tree binfo; void *data ATTRIBUTE_UNUSED; { tree t = BINFO_TYPE (binfo); CLASSTYPE_DEBUG_REQUESTED (t) = 1; /* If interface info is known, either we've already emitted the debug info or we don't need to. */ if (CLASSTYPE_INTERFACE_KNOWN (t)) return NULL_TREE; /* If the class has virtual functions, we'll emit the debug info with the vtable. */ if (TYPE_POLYMORPHIC_P (t)) return NULL_TREE; /* We cannot rely on some alien method to solve our problems, so we must write out the debug info ourselves. */ TYPE_DECL_SUPPRESS_DEBUG (TYPE_NAME (t)) = 0; rest_of_type_compilation (t, toplevel_bindings_p ()); return NULL_TREE; } #endif struct vbase_info { tree decl_ptr; tree inits; tree vbase_types; }; /* Attach to the type of the virtual base class, the pointer to the virtual base class. */ static tree dfs_find_vbases (binfo, data) tree binfo; void *data; { struct vbase_info *vi = (struct vbase_info *) data; tree binfos = BINFO_BASETYPES (binfo); int i, n_baselinks = binfos ? TREE_VEC_LENGTH (binfos) : 0; for (i = n_baselinks-1; i >= 0; i--) { tree base_binfo = TREE_VEC_ELT (binfos, i); if (TREE_VIA_VIRTUAL (base_binfo) && CLASSTYPE_SEARCH_SLOT (BINFO_TYPE (base_binfo)) == 0) { tree vbase = BINFO_TYPE (base_binfo); tree binfo = binfo_member (vbase, vi->vbase_types); CLASSTYPE_SEARCH_SLOT (vbase) = build (PLUS_EXPR, build_pointer_type (vbase), vi->decl_ptr, BINFO_OFFSET (binfo)); } } SET_BINFO_VTABLE_PATH_MARKED (binfo); SET_BINFO_NEW_VTABLE_MARKED (binfo); return NULL_TREE; } static tree dfs_init_vbase_pointers (binfo, data) tree binfo; void *data; { struct vbase_info *vi = (struct vbase_info *) data; tree type = BINFO_TYPE (binfo); tree fields; tree this_vbase_ptr; CLEAR_BINFO_VTABLE_PATH_MARKED (binfo); if (BINFO_INHERITANCE_CHAIN (binfo)) { this_vbase_ptr = TREE_CHAIN (BINFO_INHERITANCE_CHAIN (binfo)); if (TREE_VIA_VIRTUAL (binfo)) this_vbase_ptr = CLASSTYPE_SEARCH_SLOT (type); else this_vbase_ptr = convert_pointer_to_single_level (type, this_vbase_ptr); TREE_CHAIN (binfo) = this_vbase_ptr; } else this_vbase_ptr = TREE_CHAIN (binfo); /* We're going to iterate through all the pointers to virtual base-classes. They come at the beginning of the class. */ fields = TYPE_FIELDS (type); if (fields == TYPE_VFIELD (type)) /* If the first field is the vtbl pointer (as happens in the new ABI), skip it. */ fields = TREE_CHAIN (fields); if (fields == NULL_TREE || DECL_NAME (fields) == NULL_TREE || ! VBASE_NAME_P (DECL_NAME (fields))) return NULL_TREE; if (build_pointer_type (type) != TYPE_MAIN_VARIANT (TREE_TYPE (this_vbase_ptr))) my_friendly_abort (125); while (fields && DECL_NAME (fields) && VBASE_NAME_P (DECL_NAME (fields))) { tree ref = build (COMPONENT_REF, TREE_TYPE (fields), build_indirect_ref (this_vbase_ptr, NULL_PTR), fields); tree init = CLASSTYPE_SEARCH_SLOT (TREE_TYPE (TREE_TYPE (fields))); vi->inits = tree_cons (binfo_member (TREE_TYPE (TREE_TYPE (fields)), vi->vbase_types), build_modify_expr (ref, NOP_EXPR, init), vi->inits); fields = TREE_CHAIN (fields); } return NULL_TREE; } /* Sometimes this needs to clear both VTABLE_PATH and NEW_VTABLE. Other times, just NEW_VTABLE, but optimizer should make both with equal efficiency (though it does not currently). */ static tree dfs_clear_vbase_slots (binfo, data) tree binfo; void *data ATTRIBUTE_UNUSED; { tree type = BINFO_TYPE (binfo); CLASSTYPE_SEARCH_SLOT (type) = 0; CLEAR_BINFO_VTABLE_PATH_MARKED (binfo); CLEAR_BINFO_NEW_VTABLE_MARKED (binfo); return NULL_TREE; } tree init_vbase_pointers (type, decl_ptr) tree type; tree decl_ptr; { if (TYPE_USES_VIRTUAL_BASECLASSES (type)) { struct vbase_info vi; int old_flag = flag_this_is_variable; tree binfo = TYPE_BINFO (type); flag_this_is_variable = -2; /* Find all the virtual base classes, marking them for later initialization. */ vi.decl_ptr = decl_ptr; vi.vbase_types = CLASSTYPE_VBASECLASSES (type); vi.inits = NULL_TREE; dfs_walk (binfo, dfs_find_vbases, unmarked_vtable_pathp, &vi); /* Build up a list of the initializers. */ TREE_CHAIN (binfo) = decl_ptr; dfs_walk_real (binfo, dfs_init_vbase_pointers, 0, marked_vtable_pathp, &vi); dfs_walk (binfo, dfs_clear_vbase_slots, marked_new_vtablep, 0); flag_this_is_variable = old_flag; return vi.inits; } return 0; } /* get the virtual context (the vbase that directly contains the DECL_CLASS_CONTEXT of the FNDECL) that the given FNDECL is declared in, or NULL_TREE if there is none. FNDECL must come from a virtual table from a virtual base to ensure that there is only one possible DECL_CLASS_CONTEXT. We know that if there is more than one place (binfo) the fndecl that the declared, they all refer to the same binfo. See get_class_offset_1 for the check that ensures this. */ static tree virtual_context (fndecl, t, vbase) tree fndecl, t, vbase; { tree path; if (get_base_distance (DECL_CLASS_CONTEXT (fndecl), t, 0, &path) < 0) { /* DECL_CLASS_CONTEXT can be ambiguous in t. */ if (get_base_distance (DECL_CLASS_CONTEXT (fndecl), vbase, 0, &path) >= 0) { while (path) { /* Not sure if checking path == vbase is necessary here, but just in case it is. */ if (TREE_VIA_VIRTUAL (path) || path == vbase) return binfo_member (BINFO_TYPE (path), CLASSTYPE_VBASECLASSES (t)); path = BINFO_INHERITANCE_CHAIN (path); } } /* This shouldn't happen, I don't want errors! */ warning ("recoverable compiler error, fixups for virtual function"); return vbase; } while (path) { if (TREE_VIA_VIRTUAL (path)) return binfo_member (BINFO_TYPE (path), CLASSTYPE_VBASECLASSES (t)); path = BINFO_INHERITANCE_CHAIN (path); } return 0; } /* Fixups upcast offsets for one vtable. Entries may stay within the VBASE given, or they may upcast into a direct base, or they may upcast into a different vbase. We only need to do fixups in case 2 and 3. In case 2, we add in the virtual base offset to effect an upcast, in case 3, we add in the virtual base offset to effect an upcast, then subtract out the offset for the other virtual base, to effect a downcast into it. This routine mirrors fixup_vtable_deltas in functionality, though this one is runtime based, and the other is compile time based. Conceivably that routine could be removed entirely, and all fixups done at runtime. VBASE_OFFSETS is an association list of virtual bases that contains offset information for the virtual bases, so the offsets are only calculated once. The offsets are computed by where we think the vbase should be (as noted by the CLASSTYPE_SEARCH_SLOT) minus where the vbase really is. */ static void expand_upcast_fixups (binfo, addr, orig_addr, vbase, vbase_addr, t, vbase_offsets) tree binfo, addr, orig_addr, vbase, vbase_addr, t, *vbase_offsets; { tree virtuals = BINFO_VIRTUALS (binfo); tree vc; tree delta; unsigned HOST_WIDE_INT n; delta = purpose_member (vbase, *vbase_offsets); if (! delta) { delta = CLASSTYPE_SEARCH_SLOT (BINFO_TYPE (vbase)); delta = build (MINUS_EXPR, ptrdiff_type_node, delta, vbase_addr); delta = save_expr (delta); delta = tree_cons (vbase, delta, *vbase_offsets); *vbase_offsets = delta; } n = skip_rtti_stuff (&virtuals, BINFO_TYPE (binfo)); while (virtuals) { tree current_fndecl = TREE_VALUE (virtuals); if (current_fndecl && current_fndecl != abort_fndecl && (vc=virtual_context (current_fndecl, t, vbase)) != vbase) { /* This may in fact need a runtime fixup. */ tree idx = build_int_2 (n, 0); tree vtbl = BINFO_VTABLE (binfo); tree nvtbl = lookup_name (DECL_NAME (vtbl), 0); tree aref, ref, naref; tree old_delta, new_delta; tree init; if (nvtbl == NULL_TREE || nvtbl == IDENTIFIER_GLOBAL_VALUE (DECL_NAME (vtbl))) { /* Dup it if it isn't in local scope yet. */ nvtbl = build_decl (VAR_DECL, DECL_NAME (vtbl), TYPE_MAIN_VARIANT (TREE_TYPE (vtbl))); DECL_ALIGN (nvtbl) = MAX (TYPE_ALIGN (double_type_node), DECL_ALIGN (nvtbl)); TREE_READONLY (nvtbl) = 0; DECL_ARTIFICIAL (nvtbl) = 1; nvtbl = pushdecl (nvtbl); init = NULL_TREE; cp_finish_decl (nvtbl, init, NULL_TREE, LOOKUP_ONLYCONVERTING); /* We don't set DECL_VIRTUAL_P and DECL_CONTEXT on nvtbl because they wouldn't be useful; everything that wants to look at the vtable will look at the decl for the normal vtable. Setting DECL_CONTEXT also screws up decl_function_context. */ init = build (MODIFY_EXPR, TREE_TYPE (nvtbl), nvtbl, vtbl); finish_expr_stmt (init); /* Update the vtable pointers as necessary. */ ref = build_vfield_ref (build_indirect_ref (addr, NULL_PTR), DECL_CONTEXT (TYPE_VFIELD (BINFO_TYPE (binfo)))); finish_expr_stmt (build_modify_expr (ref, NOP_EXPR, nvtbl)); } assemble_external (vtbl); aref = build_array_ref (vtbl, idx); naref = build_array_ref (nvtbl, idx); old_delta = build_component_ref (aref, delta_identifier, NULL_TREE, 0); new_delta = build_component_ref (naref, delta_identifier, NULL_TREE, 0); /* This is a upcast, so we have to add the offset for the virtual base. */ old_delta = build_binary_op (PLUS_EXPR, old_delta, TREE_VALUE (delta)); if (vc) { /* If this is set, we need to subtract out the delta adjustments for the other virtual base that we downcast into. */ tree vc_delta = purpose_member (vc, *vbase_offsets); if (! vc_delta) { tree vc_addr = convert_pointer_to_real (vc, orig_addr); vc_delta = CLASSTYPE_SEARCH_SLOT (BINFO_TYPE (vc)); vc_delta = build (MINUS_EXPR, ptrdiff_type_node, vc_delta, vc_addr); vc_delta = save_expr (vc_delta); *vbase_offsets = tree_cons (vc, vc_delta, *vbase_offsets); } else vc_delta = TREE_VALUE (vc_delta); /* This is a downcast, so we have to subtract the offset for the virtual base. */ old_delta = build_binary_op (MINUS_EXPR, old_delta, vc_delta); } TREE_READONLY (new_delta) = 0; TREE_TYPE (new_delta) = cp_build_qualified_type (TREE_TYPE (new_delta), CP_TYPE_QUALS (TREE_TYPE (new_delta)) & ~TYPE_QUAL_CONST); finish_expr_stmt (build_modify_expr (new_delta, NOP_EXPR, old_delta)); } ++n; virtuals = TREE_CHAIN (virtuals); } } /* Fixup upcast offsets for all direct vtables. Patterned after expand_direct_vtbls_init. */ static void fixup_virtual_upcast_offsets (real_binfo, binfo, init_self, can_elide, addr, orig_addr, type, vbase, vbase_offsets) tree real_binfo, binfo; int init_self, can_elide; tree addr, orig_addr, type, vbase, *vbase_offsets; { tree real_binfos = BINFO_BASETYPES (real_binfo); tree binfos = BINFO_BASETYPES (binfo); int i, n_baselinks = real_binfos ? TREE_VEC_LENGTH (real_binfos) : 0; for (i = 0; i < n_baselinks; i++) { tree real_base_binfo = TREE_VEC_ELT (real_binfos, i); tree base_binfo = TREE_VEC_ELT (binfos, i); int is_not_base_vtable = i != CLASSTYPE_VFIELD_PARENT (BINFO_TYPE (real_binfo)); if (! TREE_VIA_VIRTUAL (real_base_binfo)) fixup_virtual_upcast_offsets (real_base_binfo, base_binfo, is_not_base_vtable, can_elide, addr, orig_addr, type, vbase, vbase_offsets); } #if 0 /* Before turning this on, make sure it is correct. */ if (can_elide && ! BINFO_MODIFIED (binfo)) return; #endif /* Should we use something besides CLASSTYPE_VFIELDS? */ if (init_self && CLASSTYPE_VFIELDS (BINFO_TYPE (real_binfo))) { tree new_addr = convert_pointer_to_real (binfo, addr); expand_upcast_fixups (real_binfo, new_addr, orig_addr, vbase, addr, type, vbase_offsets); } } /* Fixup all the virtual upcast offsets for TYPE. DECL_PTR is the address of the sub-object being initialized. */ static void fixup_all_virtual_upcast_offsets (type, decl_ptr) tree type; tree decl_ptr; { tree if_stmt; tree in_charge_node; tree vbases; /* Only tweak the vtables if we're in charge. */ in_charge_node = current_in_charge_parm; if (!in_charge_node) /* There's no need for any fixups in this case. */ return; in_charge_node = build_binary_op (EQ_EXPR, in_charge_node, integer_zero_node); if_stmt = begin_if_stmt (); finish_if_stmt_cond (in_charge_node, if_stmt); /* Iterate through the virtual bases, fixing up the upcast offset for each one. */ for (vbases = CLASSTYPE_VBASECLASSES (type); vbases; vbases = TREE_CHAIN (vbases)) { if (flag_vtable_thunks) /* We don't have dynamic thunks yet! So for now, just fail silently. */ ; else { tree vbase_offsets; tree addr; vbase_offsets = NULL_TREE; addr = convert_pointer_to_vbase (TREE_TYPE (vbases), decl_ptr); fixup_virtual_upcast_offsets (vbases, TYPE_BINFO (BINFO_TYPE (vbases)), 1, 0, addr, decl_ptr, type, vbases, &vbase_offsets); } } /* Close out the if-statement. */ finish_then_clause (if_stmt); finish_if_stmt (); } /* Generate the code needed to initialize all the virtual function table slots of all the virtual baseclasses. BINFO is the binfo which determines the virtual baseclasses to use. TRUE_EXP is the true object we are initializing, and DECL_PTR is the pointer to the sub-object we are initializing. */ void expand_indirect_vtbls_init (binfo, true_exp, decl_ptr) tree binfo; tree true_exp, decl_ptr; { tree type = BINFO_TYPE (binfo); /* This function executes during the finish_function() segment, AFTER the auto variables and temporary stack space has been marked unused...If space is needed for the virtual function tables, some of them might fit within what the compiler now thinks are available stack slots... These values are actually initialized at the beginnning of the function, so when the automatics use their space, they will overwrite the values that are placed here. Marking all temporary space as unavailable prevents this from happening. */ mark_all_temps_used(); if (TYPE_USES_VIRTUAL_BASECLASSES (type)) { tree vbases = CLASSTYPE_VBASECLASSES (type); struct vbase_info vi; vi.decl_ptr = (true_exp ? build_unary_op (ADDR_EXPR, true_exp, 0) : decl_ptr); vi.vbase_types = vbases; dfs_walk (binfo, dfs_find_vbases, unmarked_new_vtablep, &vi); /* Initialized with vtables of type TYPE. */ for (; vbases; vbases = TREE_CHAIN (vbases)) { tree addr; addr = convert_pointer_to_vbase (TREE_TYPE (vbases), vi.decl_ptr); /* Do all vtables from this virtual base. */ /* This assumes that virtual bases can never serve as parent binfos. (in the CLASSTYPE_VFIELD_PARENT sense) */ expand_direct_vtbls_init (vbases, TYPE_BINFO (BINFO_TYPE (vbases)), 1, 0, addr); } fixup_all_virtual_upcast_offsets (type, vi.decl_ptr); dfs_walk (binfo, dfs_clear_vbase_slots, marked_new_vtablep, 0); } } /* get virtual base class types. This adds type to the vbase_types list in reverse dfs order. Ordering is very important, so don't change it. */ static tree dfs_get_vbase_types (binfo, data) tree binfo; void *data; { tree *vbase_types = (tree *) data; if (TREE_VIA_VIRTUAL (binfo) && ! BINFO_VBASE_MARKED (binfo)) { tree new_vbase = make_binfo (integer_zero_node, binfo, BINFO_VTABLE (binfo), BINFO_VIRTUALS (binfo)); TREE_CHAIN (new_vbase) = *vbase_types; TREE_VIA_VIRTUAL (new_vbase) = 1; *vbase_types = new_vbase; SET_BINFO_VBASE_MARKED (binfo); } SET_BINFO_MARKED (binfo); return NULL_TREE; } /* Return a list of binfos for the virtual base classes for TYPE, in depth-first search order. The list is freshly allocated, so no modification is made to the current binfo hierarchy. */ tree get_vbase_types (type) tree type; { tree vbase_types; tree vbases; tree binfo; binfo = TYPE_BINFO (type); vbase_types = NULL_TREE; dfs_walk (binfo, dfs_get_vbase_types, unmarkedp, &vbase_types); dfs_walk (binfo, dfs_unmark, markedp, 0); /* Rely upon the reverse dfs ordering from dfs_get_vbase_types, and now reverse it so that we get normal dfs ordering. */ vbase_types = nreverse (vbase_types); /* unmark marked vbases */ for (vbases = vbase_types; vbases; vbases = TREE_CHAIN (vbases)) CLEAR_BINFO_VBASE_MARKED (vbases); return vbase_types; } /* 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 (t) tree t; { /* We can't do the usual TYPE_DECL_SUPPRESS_DEBUG thing with DWARF, which does not support name references between translation units. It supports symbolic references between translation units, but only within a single executable or shared library. For DWARF 2, we handle TYPE_DECL_SUPPRESS_DEBUG by pretending that the type was never defined, so we only get the members we actually define. */ if (write_symbols == DWARF_DEBUG || write_symbols == NO_DEBUG) return; /* We might have set this earlier in cp_finish_decl. */ TYPE_DECL_SUPPRESS_DEBUG (TYPE_MAIN_DECL (t)) = 0; /* If we already know how we're handling this class, handle debug info the same way. */ if (CLASSTYPE_INTERFACE_ONLY (t)) TYPE_DECL_SUPPRESS_DEBUG (TYPE_MAIN_DECL (t)) = 1; else if (CLASSTYPE_INTERFACE_KNOWN (t)) /* Don't set it. */; /* If the class has virtual functions, write out the debug info along with the vtable. */ else if (TYPE_POLYMORPHIC_P (t)) TYPE_DECL_SUPPRESS_DEBUG (TYPE_MAIN_DECL (t)) = 1; /* Otherwise, just emit the debug info normally. */ } #if 0 /* Keep this code around in case we later want to control debug info based on whether a type is "used". Currently, we only suppress debug info if we can emit it with the vtable. jason 1999-11-11) */ /* If we want debug info for a type TYPE, make sure all its base types are also marked as being potentially interesting. This avoids the problem of not writing any debug info for intermediate basetypes that have abstract virtual functions. Also mark member types. */ void note_debug_info_needed (type) tree type; { tree field; if (current_template_parms) return; if (TYPE_BEING_DEFINED (type)) /* We can't go looking for the base types and fields just yet. */ return; /* See the comment in maybe_suppress_debug_info. */ if (write_symbols == DWARF_DEBUG || write_symbols == NO_DEBUG) return; dfs_walk (TYPE_BINFO (type), dfs_debug_mark, dfs_debug_unmarkedp, 0); for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field)) { tree ttype; if (TREE_CODE (field) == FIELD_DECL && IS_AGGR_TYPE (ttype = target_type (TREE_TYPE (field))) && dfs_debug_unmarkedp (TYPE_BINFO (ttype), 0)) note_debug_info_needed (ttype); } } #endif /* Subroutines of push_class_decls (). */ /* Returns 1 iff BINFO is a base we shouldn't really be able to see into, because it (or one of the intermediate bases) depends on template parms. */ static int dependent_base_p (binfo) tree binfo; { for (; binfo; binfo = BINFO_INHERITANCE_CHAIN (binfo)) { if (currently_open_class (TREE_TYPE (binfo))) break; if (uses_template_parms (TREE_TYPE (binfo))) return 1; } return 0; } static void setup_class_bindings (name, type_binding_p) tree name; int type_binding_p; { tree type_binding = NULL_TREE; tree value_binding; /* If we've already done the lookup for this declaration, we're done. */ if (IDENTIFIER_CLASS_VALUE (name)) return; /* First, deal with the type binding. */ if (type_binding_p) { type_binding = lookup_member (current_class_type, name, /*protect=*/2, /*want_type=*/1); if (TREE_CODE (type_binding) == TREE_LIST && TREE_TYPE (type_binding) == error_mark_node) /* NAME is ambiguous. */ push_class_level_binding (name, type_binding); else pushdecl_class_level (type_binding); } /* Now, do the value binding. */ value_binding = lookup_member (current_class_type, name, /*protect=*/2, /*want_type=*/0); if (type_binding_p && (TREE_CODE (value_binding) == TYPE_DECL || (TREE_CODE (value_binding) == TREE_LIST && TREE_TYPE (value_binding) == error_mark_node && (TREE_CODE (TREE_VALUE (value_binding)) == TYPE_DECL)))) /* We found a type-binding, even when looking for a non-type binding. This means that we already processed this binding above. */ my_friendly_assert (type_binding_p, 19990401); else if (value_binding) { if (TREE_CODE (value_binding) == TREE_LIST && TREE_TYPE (value_binding) == error_mark_node) /* NAME is ambiguous. */ push_class_level_binding (name, value_binding); else { if (BASELINK_P (value_binding)) /* NAME is some overloaded functions. */ value_binding = TREE_VALUE (value_binding); pushdecl_class_level (value_binding); } } } /* Push class-level declarations for any names appearing in BINFO that are TYPE_DECLS. */ static tree dfs_push_type_decls (binfo, data) tree binfo; void *data ATTRIBUTE_UNUSED; { tree type; tree fields; type = BINFO_TYPE (binfo); for (fields = TYPE_FIELDS (type); fields; fields = TREE_CHAIN (fields)) if (DECL_NAME (fields) && TREE_CODE (fields) == TYPE_DECL && !(!same_type_p (type, current_class_type) && template_self_reference_p (type, fields))) setup_class_bindings (DECL_NAME (fields), /*type_binding_p=*/1); /* We can't just use BINFO_MARKED because envelope_add_decl uses DERIVED_FROM_P, which calls get_base_distance. */ SET_BINFO_PUSHDECLS_MARKED (binfo); return NULL_TREE; } /* Push class-level declarations for any names appearing in BINFO that are not TYPE_DECLS. */ static tree dfs_push_decls (binfo, data) tree binfo; void *data; { tree type; tree method_vec; int dep_base_p; type = BINFO_TYPE (binfo); dep_base_p = (processing_template_decl && type != current_class_type && dependent_base_p (binfo)); if (!dep_base_p) { tree fields; for (fields = TYPE_FIELDS (type); fields; fields = TREE_CHAIN (fields)) if (DECL_NAME (fields) && TREE_CODE (fields) != TYPE_DECL && TREE_CODE (fields) != USING_DECL) setup_class_bindings (DECL_NAME (fields), /*type_binding_p=*/0); else if (TREE_CODE (fields) == FIELD_DECL && ANON_AGGR_TYPE_P (TREE_TYPE (fields))) dfs_push_decls (TYPE_BINFO (TREE_TYPE (fields)), data); method_vec = (CLASS_TYPE_P (type) ? CLASSTYPE_METHOD_VEC (type) : NULL_TREE); if (method_vec) { tree *methods; tree *end; /* Farm out constructors and destructors. */ end = TREE_VEC_END (method_vec); for (methods = &TREE_VEC_ELT (method_vec, 2); *methods && methods != end; methods++) setup_class_bindings (DECL_NAME (OVL_CURRENT (*methods)), /*type_binding_p=*/0); } } CLEAR_BINFO_PUSHDECLS_MARKED (binfo); return NULL_TREE; } /* When entering the scope of a class, we cache all of the fields that that class provides within its inheritance lattice. Where ambiguities result, we mark them with `error_mark_node' so that if they are encountered without explicit qualification, we can emit an error message. */ void push_class_decls (type) tree type; { search_stack = push_search_level (search_stack, &search_obstack); /* Enter type declarations and mark. */ dfs_walk (TYPE_BINFO (type), dfs_push_type_decls, unmarked_pushdecls_p, 0); /* Enter non-type declarations and unmark. */ dfs_walk (TYPE_BINFO (type), dfs_push_decls, marked_pushdecls_p, 0); } /* Here's a subroutine we need because C lacks lambdas. */ static tree dfs_unuse_fields (binfo, data) tree binfo; void *data ATTRIBUTE_UNUSED; { tree type = TREE_TYPE (binfo); tree fields; for (fields = TYPE_FIELDS (type); fields; fields = TREE_CHAIN (fields)) { if (TREE_CODE (fields) != FIELD_DECL) continue; TREE_USED (fields) = 0; if (DECL_NAME (fields) == NULL_TREE && ANON_AGGR_TYPE_P (TREE_TYPE (fields))) unuse_fields (TREE_TYPE (fields)); } return NULL_TREE; } void unuse_fields (type) tree type; { dfs_walk (TYPE_BINFO (type), dfs_unuse_fields, unmarkedp, 0); } void pop_class_decls () { /* We haven't pushed a search level when dealing with cached classes, so we'd better not try to pop it. */ if (search_stack) search_stack = pop_search_level (search_stack); } void print_search_statistics () { #ifdef GATHER_STATISTICS fprintf (stderr, "%d fields searched in %d[%d] calls to lookup_field[_1]\n", n_fields_searched, n_calls_lookup_field, n_calls_lookup_field_1); fprintf (stderr, "%d fnfields searched in %d calls to lookup_fnfields\n", n_outer_fields_searched, n_calls_lookup_fnfields); fprintf (stderr, "%d calls to get_base_type\n", n_calls_get_base_type); #else /* GATHER_STATISTICS */ fprintf (stderr, "no search statistics\n"); #endif /* GATHER_STATISTICS */ } void init_search_processing () { gcc_obstack_init (&search_obstack); vptr_identifier = get_identifier ("_vptr"); } void reinit_search_statistics () { #ifdef GATHER_STATISTICS n_fields_searched = 0; n_calls_lookup_field = 0, n_calls_lookup_field_1 = 0; n_calls_lookup_fnfields = 0, n_calls_lookup_fnfields_1 = 0; n_calls_get_base_type = 0; n_outer_fields_searched = 0; n_contexts_saved = 0; #endif /* GATHER_STATISTICS */ } static tree add_conversions (binfo, data) tree binfo; void *data; { int i; tree method_vec = CLASSTYPE_METHOD_VEC (BINFO_TYPE (binfo)); tree *conversions = (tree *) data; /* Some builtin types have no method vector, not even an empty one. */ if (!method_vec) return NULL_TREE; for (i = 2; i < TREE_VEC_LENGTH (method_vec); ++i) { tree tmp = TREE_VEC_ELT (method_vec, i); tree name; if (!tmp || ! DECL_CONV_FN_P (OVL_CURRENT (tmp))) break; name = DECL_NAME (OVL_CURRENT (tmp)); /* Make sure we don't already have this conversion. */ if (! IDENTIFIER_MARKED (name)) { *conversions = tree_cons (binfo, tmp, *conversions); IDENTIFIER_MARKED (name) = 1; } } return NULL_TREE; } /* 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 a FUNCTION_DECL or an OVERLOAD containing the conversion functions. The TREE_PURPOSE is the BINFO from which the conversion functions in this node were selected. */ tree lookup_conversions (type) tree type; { tree t; tree conversions = NULL_TREE; if (TYPE_SIZE (type)) bfs_walk (TYPE_BINFO (type), add_conversions, 0, &conversions); for (t = conversions; t; t = TREE_CHAIN (t)) IDENTIFIER_MARKED (DECL_NAME (OVL_CURRENT (TREE_VALUE (t)))) = 0; return conversions; } struct overlap_info { tree compare_type; int found_overlap; }; /* Check whether the empty class indicated by EMPTY_BINFO is also present at offset 0 in COMPARE_TYPE, and set found_overlap if so. */ static tree dfs_check_overlap (empty_binfo, data) tree empty_binfo; void *data; { struct overlap_info *oi = (struct overlap_info *) data; tree binfo; for (binfo = TYPE_BINFO (oi->compare_type); ; binfo = BINFO_BASETYPE (binfo, 0)) { if (BINFO_TYPE (binfo) == BINFO_TYPE (empty_binfo)) { oi->found_overlap = 1; break; } else if (BINFO_BASETYPES (binfo) == NULL_TREE) break; } return NULL_TREE; } /* Trivial function to stop base traversal when we find something. */ static tree dfs_no_overlap_yet (binfo, data) tree binfo; void *data; { struct overlap_info *oi = (struct overlap_info *) data; return !oi->found_overlap ? binfo : NULL_TREE; } /* Returns nonzero if EMPTY_TYPE or any of its bases can also be found at offset 0 in NEXT_TYPE. Used in laying out empty base class subobjects. */ int types_overlap_p (empty_type, next_type) tree empty_type, next_type; { struct overlap_info oi; if (! IS_AGGR_TYPE (next_type)) return 0; oi.compare_type = next_type; oi.found_overlap = 0; dfs_walk (TYPE_BINFO (empty_type), dfs_check_overlap, dfs_no_overlap_yet, &oi); return oi.found_overlap; } /* Given a vtable VAR, determine which binfo it comes from. FIXME What about secondary vtables? */ tree binfo_for_vtable (var) tree var; { tree binfo = TYPE_BINFO (DECL_CONTEXT (var)); tree binfos; int i; while (1) { binfos = BINFO_BASETYPES (binfo); if (binfos == NULL_TREE) break; i = CLASSTYPE_VFIELD_PARENT (BINFO_TYPE (binfo)); if (i == -1) break; binfo = TREE_VEC_ELT (binfos, i); } return binfo; } /* Returns 1 iff BINFO is from a direct or indirect virtual base. */ int binfo_from_vbase (binfo) tree binfo; { for (; binfo; binfo = BINFO_INHERITANCE_CHAIN (binfo)) { if (TREE_VIA_VIRTUAL (binfo)) return 1; } return 0; }