1 /* Breadth-first and depth-first routines for
2 searching multiple-inheritance lattice for GNU C++.
3 Copyright (C) 1987, 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
4 1999, 2000, 2002, 2003, 2004 Free Software Foundation, Inc.
5 Contributed by Michael Tiemann (tiemann@cygnus.com)
7 This file is part of GCC.
9 GCC is free software; you can redistribute it and/or modify
10 it under the terms of the GNU General Public License as published by
11 the Free Software Foundation; either version 2, or (at your option)
14 GCC is distributed in the hope that it will be useful,
15 but WITHOUT ANY WARRANTY; without even the implied warranty of
16 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 GNU General Public License for more details.
19 You should have received a copy of the GNU General Public License
20 along with GCC; see the file COPYING. If not, write to
21 the Free Software Foundation, 59 Temple Place - Suite 330,
22 Boston, MA 02111-1307, USA. */
24 /* High-level class interface. */
28 #include "coretypes.h"
41 /* The class dominating the hierarchy. */
43 /* A pointer to a complete object of the indicated TYPE. */
48 static tree
dfs_check_overlap (tree
, void *);
49 static tree
dfs_no_overlap_yet (tree
, int, void *);
50 static base_kind
lookup_base_r (tree
, tree
, base_access
, bool, tree
*);
51 static int dynamic_cast_base_recurse (tree
, tree
, bool, tree
*);
52 static tree
dfs_debug_unmarkedp (tree
, int, void *);
53 static tree
dfs_debug_mark (tree
, void *);
54 static tree
add_conversions (tree
, void *);
55 static int look_for_overrides_r (tree
, tree
);
56 static tree
bfs_walk (tree
, tree (*) (tree
, void *),
57 tree (*) (tree
, int, void *), void *);
58 static tree
lookup_field_queue_p (tree
, int, void *);
59 static int shared_member_p (tree
);
60 static tree
lookup_field_r (tree
, void *);
61 static tree
dfs_accessible_queue_p (tree
, int, void *);
62 static tree
dfs_accessible_p (tree
, void *);
63 static tree
dfs_access_in_type (tree
, void *);
64 static access_kind
access_in_type (tree
, tree
);
65 static int protected_accessible_p (tree
, tree
, tree
);
66 static int friend_accessible_p (tree
, tree
, tree
);
67 static int template_self_reference_p (tree
, tree
);
68 static tree
dfs_get_pure_virtuals (tree
, void *);
71 /* Variables for gathering statistics. */
72 #ifdef GATHER_STATISTICS
73 static int n_fields_searched
;
74 static int n_calls_lookup_field
, n_calls_lookup_field_1
;
75 static int n_calls_lookup_fnfields
, n_calls_lookup_fnfields_1
;
76 static int n_calls_get_base_type
;
77 static int n_outer_fields_searched
;
78 static int n_contexts_saved
;
79 #endif /* GATHER_STATISTICS */
82 /* Worker for lookup_base. BINFO is the binfo we are searching at,
83 BASE is the RECORD_TYPE we are searching for. ACCESS is the
84 required access checks. IS_VIRTUAL indicates if BINFO is morally
87 If BINFO is of the required type, then *BINFO_PTR is examined to
88 compare with any other instance of BASE we might have already
89 discovered. *BINFO_PTR is initialized and a base_kind return value
90 indicates what kind of base was located.
92 Otherwise BINFO's bases are searched. */
95 lookup_base_r (tree binfo
, tree base
, base_access access
,
96 bool is_virtual
, /* inside a virtual part */
101 base_kind found
= bk_not_base
;
103 if (same_type_p (BINFO_TYPE (binfo
), base
))
105 /* We have found a base. Check against what we have found
107 found
= bk_same_type
;
109 found
= bk_via_virtual
;
113 else if (binfo
!= *binfo_ptr
)
115 if (access
!= ba_any
)
117 else if (!is_virtual
)
118 /* Prefer a non-virtual base. */
126 for (i
= 0; BINFO_BASE_ITERATE (binfo
, i
, base_binfo
); i
++)
130 bk
= lookup_base_r (base_binfo
, base
,
132 is_virtual
|| BINFO_VIRTUAL_P (base_binfo
),
138 if (access
!= ba_any
)
147 my_friendly_assert (found
== bk_not_base
, 20010723);
152 if (found
!= bk_ambig
)
166 /* Returns true if type BASE is accessible in T. (BASE is known to be
167 a (possibly non-proper) base class of T.) */
170 accessible_base_p (tree t
, tree base
)
174 /* [class.access.base]
176 A base class is said to be accessible if an invented public
177 member of the base class is accessible.
179 If BASE is a non-proper base, this condition is trivially
181 if (same_type_p (t
, base
))
183 /* Rather than inventing a public member, we use the implicit
184 public typedef created in the scope of every class. */
185 decl
= TYPE_FIELDS (base
);
186 while (!DECL_SELF_REFERENCE_P (decl
))
187 decl
= TREE_CHAIN (decl
);
188 while (ANON_AGGR_TYPE_P (t
))
189 t
= TYPE_CONTEXT (t
);
190 return accessible_p (t
, decl
);
193 /* Lookup BASE in the hierarchy dominated by T. Do access checking as
194 ACCESS specifies. Return the binfo we discover. If KIND_PTR is
195 non-NULL, fill with information about what kind of base we
198 If the base is inaccessible, or ambiguous, and the ba_quiet bit is
199 not set in ACCESS, then an error is issued and error_mark_node is
200 returned. If the ba_quiet bit is set, then no error is issued and
201 NULL_TREE is returned. */
204 lookup_base (tree t
, tree base
, base_access access
, base_kind
*kind_ptr
)
206 tree binfo
= NULL_TREE
; /* The binfo we've found so far. */
207 tree t_binfo
= NULL_TREE
;
210 if (t
== error_mark_node
|| base
== error_mark_node
)
213 *kind_ptr
= bk_not_base
;
214 return error_mark_node
;
216 my_friendly_assert (TYPE_P (base
), 20011127);
225 t
= complete_type (TYPE_MAIN_VARIANT (t
));
226 t_binfo
= TYPE_BINFO (t
);
229 base
= complete_type (TYPE_MAIN_VARIANT (base
));
232 bk
= lookup_base_r (t_binfo
, base
, access
, 0, &binfo
);
236 /* Check that the base is unambiguous and accessible. */
237 if (access
!= ba_any
)
245 if (!(access
& ba_quiet
))
247 error ("`%T' is an ambiguous base of `%T'", base
, t
);
248 binfo
= error_mark_node
;
253 if ((access
& ~ba_quiet
) != ba_ignore
254 /* If BASE is incomplete, then BASE and TYPE are probably
255 the same, in which case BASE is accessible. If they
256 are not the same, then TYPE is invalid. In that case,
257 there's no need to issue another error here, and
258 there's no implicit typedef to use in the code that
259 follows, so we skip the check. */
260 && COMPLETE_TYPE_P (base
)
261 && !accessible_base_p (t
, base
))
263 if (!(access
& ba_quiet
))
265 error ("`%T' is an inaccessible base of `%T'", base
, t
);
266 binfo
= error_mark_node
;
270 bk
= bk_inaccessible
;
281 /* Worker function for get_dynamic_cast_base_type. */
284 dynamic_cast_base_recurse (tree subtype
, tree binfo
, bool is_via_virtual
,
292 if (BINFO_TYPE (binfo
) == subtype
)
298 *offset_ptr
= BINFO_OFFSET (binfo
);
303 accesses
= BINFO_BASE_ACCESSES (binfo
);
304 for (i
= 0; BINFO_BASE_ITERATE (binfo
, i
, base_binfo
); i
++)
306 tree base_access
= TREE_VEC_ELT (accesses
, i
);
309 if (base_access
!= access_public_node
)
311 rval
= dynamic_cast_base_recurse
312 (subtype
, base_binfo
,
313 is_via_virtual
|| BINFO_VIRTUAL_P (base_binfo
), offset_ptr
);
317 worst
= worst
>= 0 ? -3 : worst
;
320 else if (rval
== -3 && worst
!= -1)
326 /* The dynamic cast runtime needs a hint about how the static SUBTYPE type
327 started from is related to the required TARGET type, in order to optimize
328 the inheritance graph search. This information is independent of the
329 current context, and ignores private paths, hence get_base_distance is
330 inappropriate. Return a TREE specifying the base offset, BOFF.
331 BOFF >= 0, there is only one public non-virtual SUBTYPE base at offset BOFF,
332 and there are no public virtual SUBTYPE bases.
333 BOFF == -1, SUBTYPE occurs as multiple public virtual or non-virtual bases.
334 BOFF == -2, SUBTYPE is not a public base.
335 BOFF == -3, SUBTYPE occurs as multiple public non-virtual bases. */
338 get_dynamic_cast_base_type (tree subtype
, tree target
)
340 tree offset
= NULL_TREE
;
341 int boff
= dynamic_cast_base_recurse (subtype
, TYPE_BINFO (target
),
346 offset
= build_int_2 (boff
, -1);
347 TREE_TYPE (offset
) = ssizetype
;
351 /* Search for a member with name NAME in a multiple inheritance
352 lattice specified by TYPE. If it does not exist, return NULL_TREE.
353 If the member is ambiguously referenced, return `error_mark_node'.
354 Otherwise, return a DECL with the indicated name. If WANT_TYPE is
355 true, type declarations are preferred. */
357 /* Do a 1-level search for NAME as a member of TYPE. The caller must
358 figure out whether it can access this field. (Since it is only one
359 level, this is reasonable.) */
362 lookup_field_1 (tree type
, tree name
, bool want_type
)
366 if (TREE_CODE (type
) == TEMPLATE_TYPE_PARM
367 || TREE_CODE (type
) == BOUND_TEMPLATE_TEMPLATE_PARM
368 || TREE_CODE (type
) == TYPENAME_TYPE
)
369 /* The TYPE_FIELDS of a TEMPLATE_TYPE_PARM and
370 BOUND_TEMPLATE_TEMPLATE_PARM are not fields at all;
371 instead TYPE_FIELDS is the TEMPLATE_PARM_INDEX. (Miraculously,
372 the code often worked even when we treated the index as a list
374 The TYPE_FIELDS of TYPENAME_TYPE is its TYPENAME_TYPE_FULLNAME. */
378 && DECL_LANG_SPECIFIC (TYPE_NAME (type
))
379 && DECL_SORTED_FIELDS (TYPE_NAME (type
)))
381 tree
*fields
= &DECL_SORTED_FIELDS (TYPE_NAME (type
))->elts
[0];
382 int lo
= 0, hi
= DECL_SORTED_FIELDS (TYPE_NAME (type
))->len
;
389 #ifdef GATHER_STATISTICS
391 #endif /* GATHER_STATISTICS */
393 if (DECL_NAME (fields
[i
]) > name
)
395 else if (DECL_NAME (fields
[i
]) < name
)
401 /* We might have a nested class and a field with the
402 same name; we sorted them appropriately via
403 field_decl_cmp, so just look for the first or last
404 field with this name. */
409 while (i
>= lo
&& DECL_NAME (fields
[i
]) == name
);
410 if (TREE_CODE (field
) != TYPE_DECL
411 && !DECL_CLASS_TEMPLATE_P (field
))
418 while (i
< hi
&& DECL_NAME (fields
[i
]) == name
);
426 field
= TYPE_FIELDS (type
);
428 #ifdef GATHER_STATISTICS
429 n_calls_lookup_field_1
++;
430 #endif /* GATHER_STATISTICS */
431 for (field
= TYPE_FIELDS (type
); field
; field
= TREE_CHAIN (field
))
433 #ifdef GATHER_STATISTICS
435 #endif /* GATHER_STATISTICS */
436 my_friendly_assert (DECL_P (field
), 0);
437 if (DECL_NAME (field
) == NULL_TREE
438 && ANON_AGGR_TYPE_P (TREE_TYPE (field
)))
440 tree temp
= lookup_field_1 (TREE_TYPE (field
), name
, want_type
);
444 if (TREE_CODE (field
) == USING_DECL
)
446 /* We generally treat class-scope using-declarations as
447 ARM-style access specifications, because support for the
448 ISO semantics has not been implemented. So, in general,
449 there's no reason to return a USING_DECL, and the rest of
450 the compiler cannot handle that. Once the class is
451 defined, USING_DECLs are purged from TYPE_FIELDS; see
452 handle_using_decl. However, we make special efforts to
453 make using-declarations in template classes work
455 if (CLASSTYPE_TEMPLATE_INFO (type
)
456 && !CLASSTYPE_USE_TEMPLATE (type
)
457 && !TREE_TYPE (field
))
463 if (DECL_NAME (field
) == name
465 || TREE_CODE (field
) == TYPE_DECL
466 || DECL_CLASS_TEMPLATE_P (field
)))
470 if (name
== vptr_identifier
)
472 /* Give the user what s/he thinks s/he wants. */
473 if (TYPE_POLYMORPHIC_P (type
))
474 return TYPE_VFIELD (type
);
479 /* There are a number of cases we need to be aware of here:
480 current_class_type current_function_decl
487 Those last two make life interesting. If we're in a function which is
488 itself inside a class, we need decls to go into the fn's decls (our
489 second case below). But if we're in a class and the class itself is
490 inside a function, we need decls to go into the decls for the class. To
491 achieve this last goal, we must see if, when both current_class_ptr and
492 current_function_decl are set, the class was declared inside that
493 function. If so, we know to put the decls into the class's scope. */
498 if (current_function_decl
== NULL_TREE
)
499 return current_class_type
;
500 if (current_class_type
== NULL_TREE
)
501 return current_function_decl
;
502 if ((DECL_FUNCTION_MEMBER_P (current_function_decl
)
503 && same_type_p (DECL_CONTEXT (current_function_decl
),
505 || (DECL_FRIEND_CONTEXT (current_function_decl
)
506 && same_type_p (DECL_FRIEND_CONTEXT (current_function_decl
),
507 current_class_type
)))
508 return current_function_decl
;
510 return current_class_type
;
513 /* Returns nonzero if we are currently in a function scope. Note
514 that this function returns zero if we are within a local class, but
515 not within a member function body of the local class. */
518 at_function_scope_p (void)
520 tree cs
= current_scope ();
521 return cs
&& TREE_CODE (cs
) == FUNCTION_DECL
;
524 /* Returns true if the innermost active scope is a class scope. */
527 at_class_scope_p (void)
529 tree cs
= current_scope ();
530 return cs
&& TYPE_P (cs
);
533 /* Returns true if the innermost active scope is a namespace scope. */
536 at_namespace_scope_p (void)
538 /* We are in a namespace scope if we are not it a class scope or a
540 return !current_scope();
543 /* Return the scope of DECL, as appropriate when doing name-lookup. */
546 context_for_name_lookup (tree decl
)
550 For the purposes of name lookup, after the anonymous union
551 definition, the members of the anonymous union are considered to
552 have been defined in the scope in which the anonymous union is
554 tree context
= DECL_CONTEXT (decl
);
556 while (context
&& TYPE_P (context
) && ANON_AGGR_TYPE_P (context
))
557 context
= TYPE_CONTEXT (context
);
559 context
= global_namespace
;
564 /* The accessibility routines use BINFO_ACCESS for scratch space
565 during the computation of the accessibility of some declaration. */
567 #define BINFO_ACCESS(NODE) \
568 ((access_kind) ((TREE_PUBLIC (NODE) << 1) | TREE_PRIVATE (NODE)))
570 /* Set the access associated with NODE to ACCESS. */
572 #define SET_BINFO_ACCESS(NODE, ACCESS) \
573 ((TREE_PUBLIC (NODE) = ((ACCESS) & 2) != 0), \
574 (TREE_PRIVATE (NODE) = ((ACCESS) & 1) != 0))
576 /* Called from access_in_type via dfs_walk. Calculate the access to
577 DATA (which is really a DECL) in BINFO. */
580 dfs_access_in_type (tree binfo
, void *data
)
582 tree decl
= (tree
) data
;
583 tree type
= BINFO_TYPE (binfo
);
584 access_kind access
= ak_none
;
586 if (context_for_name_lookup (decl
) == type
)
588 /* If we have descended to the scope of DECL, just note the
589 appropriate access. */
590 if (TREE_PRIVATE (decl
))
592 else if (TREE_PROTECTED (decl
))
593 access
= ak_protected
;
599 /* First, check for an access-declaration that gives us more
600 access to the DECL. The CONST_DECL for an enumeration
601 constant will not have DECL_LANG_SPECIFIC, and thus no
603 if (DECL_LANG_SPECIFIC (decl
) && !DECL_DISCRIMINATOR_P (decl
))
605 tree decl_access
= purpose_member (type
, DECL_ACCESS (decl
));
609 decl_access
= TREE_VALUE (decl_access
);
611 if (decl_access
== access_public_node
)
613 else if (decl_access
== access_protected_node
)
614 access
= ak_protected
;
615 else if (decl_access
== access_private_node
)
618 my_friendly_assert (false, 20030217);
625 tree base_binfo
, accesses
;
627 /* Otherwise, scan our baseclasses, and pick the most favorable
629 accesses
= BINFO_BASE_ACCESSES (binfo
);
630 for (i
= 0; BINFO_BASE_ITERATE (binfo
, i
, base_binfo
); i
++)
632 tree base_access
= TREE_VEC_ELT (accesses
, i
);
633 access_kind base_access_now
= BINFO_ACCESS (base_binfo
);
635 if (base_access_now
== ak_none
|| base_access_now
== ak_private
)
636 /* If it was not accessible in the base, or only
637 accessible as a private member, we can't access it
639 base_access_now
= ak_none
;
640 else if (base_access
== access_protected_node
)
641 /* Public and protected members in the base become
643 base_access_now
= ak_protected
;
644 else if (base_access
== access_private_node
)
645 /* Public and protected members in the base become
647 base_access_now
= ak_private
;
649 /* See if the new access, via this base, gives more
650 access than our previous best access. */
651 if (base_access_now
!= ak_none
652 && (access
== ak_none
|| base_access_now
< access
))
654 access
= base_access_now
;
656 /* If the new access is public, we can't do better. */
657 if (access
== ak_public
)
664 /* Note the access to DECL in TYPE. */
665 SET_BINFO_ACCESS (binfo
, access
);
667 /* Mark TYPE as visited so that if we reach it again we do not
668 duplicate our efforts here. */
669 BINFO_MARKED (binfo
) = 1;
674 /* Return the access to DECL in TYPE. */
677 access_in_type (tree type
, tree decl
)
679 tree binfo
= TYPE_BINFO (type
);
681 /* We must take into account
685 If a name can be reached by several paths through a multiple
686 inheritance graph, the access is that of the path that gives
689 The algorithm we use is to make a post-order depth-first traversal
690 of the base-class hierarchy. As we come up the tree, we annotate
691 each node with the most lenient access. */
692 dfs_walk_real (binfo
, 0, dfs_access_in_type
, unmarkedp
, decl
);
693 dfs_walk (binfo
, dfs_unmark
, markedp
, 0);
695 return BINFO_ACCESS (binfo
);
698 /* Called from accessible_p via dfs_walk. */
701 dfs_accessible_queue_p (tree derived
, int ix
, void *data ATTRIBUTE_UNUSED
)
703 tree binfo
= BINFO_BASE_BINFO (derived
, ix
);
705 if (BINFO_MARKED (binfo
))
708 /* If this class is inherited via private or protected inheritance,
709 then we can't see it, unless we are a friend of the derived class. */
710 if (BINFO_BASE_ACCESS (derived
, ix
) != access_public_node
711 && !is_friend (BINFO_TYPE (derived
), current_scope ()))
717 /* Called from accessible_p via dfs_walk. */
720 dfs_accessible_p (tree binfo
, void *data ATTRIBUTE_UNUSED
)
724 BINFO_MARKED (binfo
) = 1;
725 access
= BINFO_ACCESS (binfo
);
726 if (access
!= ak_none
727 && is_friend (BINFO_TYPE (binfo
), current_scope ()))
733 /* Returns nonzero if it is OK to access DECL through an object
734 indicated by BINFO in the context of DERIVED. */
737 protected_accessible_p (tree decl
, tree derived
, tree binfo
)
741 /* We're checking this clause from [class.access.base]
743 m as a member of N is protected, and the reference occurs in a
744 member or friend of class N, or in a member or friend of a
745 class P derived from N, where m as a member of P is private or
748 Here DERIVED is a possible P and DECL is m. accessible_p will
749 iterate over various values of N, but the access to m in DERIVED
752 Note that I believe that the passage above is wrong, and should read
753 "...is private or protected or public"; otherwise you get bizarre results
754 whereby a public using-decl can prevent you from accessing a protected
755 member of a base. (jason 2000/02/28) */
757 /* If DERIVED isn't derived from m's class, then it can't be a P. */
758 if (!DERIVED_FROM_P (context_for_name_lookup (decl
), derived
))
761 access
= access_in_type (derived
, decl
);
763 /* If m is inaccessible in DERIVED, then it's not a P. */
764 if (access
== ak_none
)
769 When a friend or a member function of a derived class references
770 a protected nonstatic member of a base class, an access check
771 applies in addition to those described earlier in clause
772 _class.access_) Except when forming a pointer to member
773 (_expr.unary.op_), the access must be through a pointer to,
774 reference to, or object of the derived class itself (or any class
775 derived from that class) (_expr.ref_). If the access is to form
776 a pointer to member, the nested-name-specifier shall name the
777 derived class (or any class derived from that class). */
778 if (DECL_NONSTATIC_MEMBER_P (decl
))
780 /* We can tell through what the reference is occurring by
781 chasing BINFO up to the root. */
783 while (BINFO_INHERITANCE_CHAIN (t
))
784 t
= BINFO_INHERITANCE_CHAIN (t
);
786 if (!DERIVED_FROM_P (derived
, BINFO_TYPE (t
)))
793 /* Returns nonzero if SCOPE is a friend of a type which would be able
794 to access DECL through the object indicated by BINFO. */
797 friend_accessible_p (tree scope
, tree decl
, tree binfo
)
799 tree befriending_classes
;
805 if (TREE_CODE (scope
) == FUNCTION_DECL
806 || DECL_FUNCTION_TEMPLATE_P (scope
))
807 befriending_classes
= DECL_BEFRIENDING_CLASSES (scope
);
808 else if (TYPE_P (scope
))
809 befriending_classes
= CLASSTYPE_BEFRIENDING_CLASSES (scope
);
813 for (t
= befriending_classes
; t
; t
= TREE_CHAIN (t
))
814 if (protected_accessible_p (decl
, TREE_VALUE (t
), binfo
))
817 /* Nested classes are implicitly friends of their enclosing types, as
818 per core issue 45 (this is a change from the standard). */
820 for (t
= TYPE_CONTEXT (scope
); t
&& TYPE_P (t
); t
= TYPE_CONTEXT (t
))
821 if (protected_accessible_p (decl
, t
, binfo
))
824 if (TREE_CODE (scope
) == FUNCTION_DECL
825 || DECL_FUNCTION_TEMPLATE_P (scope
))
827 /* Perhaps this SCOPE is a member of a class which is a
829 if (DECL_CLASS_SCOPE_P (decl
)
830 && friend_accessible_p (DECL_CONTEXT (scope
), decl
, binfo
))
833 /* Or an instantiation of something which is a friend. */
834 if (DECL_TEMPLATE_INFO (scope
))
835 return friend_accessible_p (DECL_TI_TEMPLATE (scope
), decl
, binfo
);
837 else if (CLASSTYPE_TEMPLATE_INFO (scope
))
838 return friend_accessible_p (CLASSTYPE_TI_TEMPLATE (scope
), decl
, binfo
);
843 /* DECL is a declaration from a base class of TYPE, which was the
844 class used to name DECL. Return nonzero if, in the current
845 context, DECL is accessible. If TYPE is actually a BINFO node,
846 then we can tell in what context the access is occurring by looking
847 at the most derived class along the path indicated by BINFO. */
850 accessible_p (tree type
, tree decl
)
857 /* Nonzero if it's OK to access DECL if it has protected
858 accessibility in TYPE. */
859 int protected_ok
= 0;
861 /* If this declaration is in a block or namespace scope, there's no
863 if (!TYPE_P (context_for_name_lookup (decl
)))
866 /* There is no need to perform access checks inside a thunk. */
867 scope
= current_scope ();
868 if (scope
&& DECL_THUNK_P (scope
))
871 /* In a template declaration, we cannot be sure whether the
872 particular specialization that is instantiated will be a friend
873 or not. Therefore, all access checks are deferred until
875 if (processing_template_decl
)
881 type
= BINFO_TYPE (type
);
884 binfo
= TYPE_BINFO (type
);
886 /* [class.access.base]
888 A member m is accessible when named in class N if
890 --m as a member of N is public, or
892 --m as a member of N is private, and the reference occurs in a
893 member or friend of class N, or
895 --m as a member of N is protected, and the reference occurs in a
896 member or friend of class N, or in a member or friend of a
897 class P derived from N, where m as a member of P is private or
900 --there exists a base class B of N that is accessible at the point
901 of reference, and m is accessible when named in class B.
903 We walk the base class hierarchy, checking these conditions. */
905 /* Figure out where the reference is occurring. Check to see if
906 DECL is private or protected in this scope, since that will
907 determine whether protected access is allowed. */
908 if (current_class_type
)
909 protected_ok
= protected_accessible_p (decl
, current_class_type
, binfo
);
911 /* Now, loop through the classes of which we are a friend. */
913 protected_ok
= friend_accessible_p (scope
, decl
, binfo
);
915 /* Standardize the binfo that access_in_type will use. We don't
916 need to know what path was chosen from this point onwards. */
917 binfo
= TYPE_BINFO (type
);
919 /* Compute the accessibility of DECL in the class hierarchy
920 dominated by type. */
921 access
= access_in_type (type
, decl
);
922 if (access
== ak_public
923 || (access
== ak_protected
&& protected_ok
))
927 /* Walk the hierarchy again, looking for a base class that allows
929 t
= dfs_walk (binfo
, dfs_accessible_p
, dfs_accessible_queue_p
, 0);
930 /* Clear any mark bits. Note that we have to walk the whole tree
931 here, since we have aborted the previous walk from some point
933 dfs_walk (binfo
, dfs_unmark
, 0, 0);
935 return t
!= NULL_TREE
;
939 struct lookup_field_info
{
940 /* The type in which we're looking. */
942 /* The name of the field for which we're looking. */
944 /* If non-NULL, the current result of the lookup. */
946 /* The path to RVAL. */
948 /* If non-NULL, the lookup was ambiguous, and this is a list of the
951 /* If nonzero, we are looking for types, not data members. */
953 /* If something went wrong, a message indicating what. */
957 /* Returns nonzero if BINFO is not hidden by the value found by the
958 lookup so far. If BINFO is hidden, then there's no need to look in
959 it. DATA is really a struct lookup_field_info. Called from
960 lookup_field via breadth_first_search. */
963 lookup_field_queue_p (tree derived
, int ix
, void *data
)
965 tree binfo
= BINFO_BASE_BINFO (derived
, ix
);
966 struct lookup_field_info
*lfi
= (struct lookup_field_info
*) data
;
968 /* Don't look for constructors or destructors in base classes. */
969 if (IDENTIFIER_CTOR_OR_DTOR_P (lfi
->name
))
972 /* If this base class is hidden by the best-known value so far, we
973 don't need to look. */
974 if (lfi
->rval_binfo
&& original_binfo (binfo
, lfi
->rval_binfo
))
977 /* If this is a dependent base, don't look in it. */
978 if (BINFO_DEPENDENT_BASE_P (binfo
))
984 /* Within the scope of a template class, you can refer to the to the
985 current specialization with the name of the template itself. For
988 template <typename T> struct S { S* sp; }
990 Returns nonzero if DECL is such a declaration in a class TYPE. */
993 template_self_reference_p (tree type
, tree decl
)
995 return (CLASSTYPE_USE_TEMPLATE (type
)
996 && PRIMARY_TEMPLATE_P (CLASSTYPE_TI_TEMPLATE (type
))
997 && TREE_CODE (decl
) == TYPE_DECL
998 && DECL_ARTIFICIAL (decl
)
999 && DECL_NAME (decl
) == constructor_name (type
));
1003 /* Nonzero for a class member means that it is shared between all objects
1006 [class.member.lookup]:If the resulting set of declarations are not all
1007 from sub-objects of the same type, or the set has a nonstatic member
1008 and includes members from distinct sub-objects, there is an ambiguity
1009 and the program is ill-formed.
1011 This function checks that T contains no nonstatic members. */
1014 shared_member_p (tree t
)
1016 if (TREE_CODE (t
) == VAR_DECL
|| TREE_CODE (t
) == TYPE_DECL \
1017 || TREE_CODE (t
) == CONST_DECL
)
1019 if (is_overloaded_fn (t
))
1021 for (; t
; t
= OVL_NEXT (t
))
1023 tree fn
= OVL_CURRENT (t
);
1024 if (DECL_NONSTATIC_MEMBER_FUNCTION_P (fn
))
1032 /* DATA is really a struct lookup_field_info. Look for a field with
1033 the name indicated there in BINFO. If this function returns a
1034 non-NULL value it is the result of the lookup. Called from
1035 lookup_field via breadth_first_search. */
1038 lookup_field_r (tree binfo
, void *data
)
1040 struct lookup_field_info
*lfi
= (struct lookup_field_info
*) data
;
1041 tree type
= BINFO_TYPE (binfo
);
1042 tree nval
= NULL_TREE
;
1044 /* First, look for a function. There can't be a function and a data
1045 member with the same name, and if there's a function and a type
1046 with the same name, the type is hidden by the function. */
1047 if (!lfi
->want_type
)
1049 int idx
= lookup_fnfields_1 (type
, lfi
->name
);
1051 nval
= VEC_index (tree
, CLASSTYPE_METHOD_VEC (type
), idx
);
1055 /* Look for a data member or type. */
1056 nval
= lookup_field_1 (type
, lfi
->name
, lfi
->want_type
);
1058 /* If there is no declaration with the indicated name in this type,
1059 then there's nothing to do. */
1063 /* If we're looking up a type (as with an elaborated type specifier)
1064 we ignore all non-types we find. */
1065 if (lfi
->want_type
&& TREE_CODE (nval
) != TYPE_DECL
1066 && !DECL_CLASS_TEMPLATE_P (nval
))
1068 if (lfi
->name
== TYPE_IDENTIFIER (type
))
1070 /* If the aggregate has no user defined constructors, we allow
1071 it to have fields with the same name as the enclosing type.
1072 If we are looking for that name, find the corresponding
1074 for (nval
= TREE_CHAIN (nval
); nval
; nval
= TREE_CHAIN (nval
))
1075 if (DECL_NAME (nval
) == lfi
->name
1076 && TREE_CODE (nval
) == TYPE_DECL
)
1081 if (!nval
&& CLASSTYPE_NESTED_UTDS (type
) != NULL
)
1083 binding_entry e
= binding_table_find (CLASSTYPE_NESTED_UTDS (type
),
1086 nval
= TYPE_MAIN_DECL (e
->type
);
1092 /* You must name a template base class with a template-id. */
1093 if (!same_type_p (type
, lfi
->type
)
1094 && template_self_reference_p (type
, nval
))
1097 /* If the lookup already found a match, and the new value doesn't
1098 hide the old one, we might have an ambiguity. */
1099 if (lfi
->rval_binfo
&& !original_binfo (lfi
->rval_binfo
, binfo
))
1101 if (nval
== lfi
->rval
&& shared_member_p (nval
))
1102 /* The two things are really the same. */
1104 else if (original_binfo (binfo
, lfi
->rval_binfo
))
1105 /* The previous value hides the new one. */
1109 /* We have a real ambiguity. We keep a chain of all the
1111 if (!lfi
->ambiguous
&& lfi
->rval
)
1113 /* This is the first time we noticed an ambiguity. Add
1114 what we previously thought was a reasonable candidate
1116 lfi
->ambiguous
= tree_cons (NULL_TREE
, lfi
->rval
, NULL_TREE
);
1117 TREE_TYPE (lfi
->ambiguous
) = error_mark_node
;
1120 /* Add the new value. */
1121 lfi
->ambiguous
= tree_cons (NULL_TREE
, nval
, lfi
->ambiguous
);
1122 TREE_TYPE (lfi
->ambiguous
) = error_mark_node
;
1123 lfi
->errstr
= "request for member `%D' is ambiguous";
1129 lfi
->rval_binfo
= binfo
;
1135 /* Return a "baselink" which BASELINK_BINFO, BASELINK_ACCESS_BINFO,
1136 BASELINK_FUNCTIONS, and BASELINK_OPTYPE set to BINFO, ACCESS_BINFO,
1137 FUNCTIONS, and OPTYPE respectively. */
1140 build_baselink (tree binfo
, tree access_binfo
, tree functions
, tree optype
)
1144 my_friendly_assert (TREE_CODE (functions
) == FUNCTION_DECL
1145 || TREE_CODE (functions
) == TEMPLATE_DECL
1146 || TREE_CODE (functions
) == TEMPLATE_ID_EXPR
1147 || TREE_CODE (functions
) == OVERLOAD
,
1149 my_friendly_assert (!optype
|| TYPE_P (optype
), 20020730);
1150 my_friendly_assert (TREE_TYPE (functions
), 20020805);
1152 baselink
= make_node (BASELINK
);
1153 TREE_TYPE (baselink
) = TREE_TYPE (functions
);
1154 BASELINK_BINFO (baselink
) = binfo
;
1155 BASELINK_ACCESS_BINFO (baselink
) = access_binfo
;
1156 BASELINK_FUNCTIONS (baselink
) = functions
;
1157 BASELINK_OPTYPE (baselink
) = optype
;
1162 /* Look for a member named NAME in an inheritance lattice dominated by
1163 XBASETYPE. If PROTECT is 0 or two, we do not check access. If it
1164 is 1, we enforce accessibility. If PROTECT is zero, then, for an
1165 ambiguous lookup, we return NULL. If PROTECT is 1, we issue error
1166 messages about inaccessible or ambiguous lookup. If PROTECT is 2,
1167 we return a TREE_LIST whose TREE_TYPE is error_mark_node and whose
1168 TREE_VALUEs are the list of ambiguous candidates.
1170 WANT_TYPE is 1 when we should only return TYPE_DECLs.
1172 If nothing can be found return NULL_TREE and do not issue an error. */
1175 lookup_member (tree xbasetype
, tree name
, int protect
, bool want_type
)
1177 tree rval
, rval_binfo
= NULL_TREE
;
1178 tree type
= NULL_TREE
, basetype_path
= NULL_TREE
;
1179 struct lookup_field_info lfi
;
1181 /* rval_binfo is the binfo associated with the found member, note,
1182 this can be set with useful information, even when rval is not
1183 set, because it must deal with ALL members, not just non-function
1184 members. It is used for ambiguity checking and the hidden
1185 checks. Whereas rval is only set if a proper (not hidden)
1186 non-function member is found. */
1188 const char *errstr
= 0;
1190 my_friendly_assert (TREE_CODE (name
) == IDENTIFIER_NODE
, 20030624);
1192 if (TREE_CODE (xbasetype
) == TREE_BINFO
)
1194 type
= BINFO_TYPE (xbasetype
);
1195 basetype_path
= xbasetype
;
1199 my_friendly_assert (IS_AGGR_TYPE_CODE (TREE_CODE (xbasetype
)), 20030624);
1201 xbasetype
= NULL_TREE
;
1204 type
= complete_type (type
);
1206 basetype_path
= TYPE_BINFO (type
);
1211 #ifdef GATHER_STATISTICS
1212 n_calls_lookup_field
++;
1213 #endif /* GATHER_STATISTICS */
1215 memset (&lfi
, 0, sizeof (lfi
));
1218 lfi
.want_type
= want_type
;
1219 bfs_walk (basetype_path
, &lookup_field_r
, &lookup_field_queue_p
, &lfi
);
1221 rval_binfo
= lfi
.rval_binfo
;
1223 type
= BINFO_TYPE (rval_binfo
);
1224 errstr
= lfi
.errstr
;
1226 /* If we are not interested in ambiguities, don't report them;
1227 just return NULL_TREE. */
1228 if (!protect
&& lfi
.ambiguous
)
1234 return lfi
.ambiguous
;
1241 In the case of overloaded function names, access control is
1242 applied to the function selected by overloaded resolution. */
1243 if (rval
&& protect
&& !is_overloaded_fn (rval
))
1244 perform_or_defer_access_check (basetype_path
, rval
);
1246 if (errstr
&& protect
)
1248 error (errstr
, name
, type
);
1250 print_candidates (lfi
.ambiguous
);
1251 rval
= error_mark_node
;
1254 if (rval
&& is_overloaded_fn (rval
))
1255 rval
= build_baselink (rval_binfo
, basetype_path
, rval
,
1256 (IDENTIFIER_TYPENAME_P (name
)
1257 ? TREE_TYPE (name
): NULL_TREE
));
1261 /* Like lookup_member, except that if we find a function member we
1262 return NULL_TREE. */
1265 lookup_field (tree xbasetype
, tree name
, int protect
, bool want_type
)
1267 tree rval
= lookup_member (xbasetype
, name
, protect
, want_type
);
1269 /* Ignore functions, but propagate the ambiguity list. */
1270 if (!error_operand_p (rval
)
1271 && (rval
&& BASELINK_P (rval
)))
1277 /* Like lookup_member, except that if we find a non-function member we
1278 return NULL_TREE. */
1281 lookup_fnfields (tree xbasetype
, tree name
, int protect
)
1283 tree rval
= lookup_member (xbasetype
, name
, protect
, /*want_type=*/false);
1285 /* Ignore non-functions, but propagate the ambiguity list. */
1286 if (!error_operand_p (rval
)
1287 && (rval
&& !BASELINK_P (rval
)))
1293 /* Return the index in the CLASSTYPE_METHOD_VEC for CLASS_TYPE
1294 corresponding to "operator TYPE ()", or -1 if there is no such
1295 operator. Only CLASS_TYPE itself is searched; this routine does
1296 not scan the base classes of CLASS_TYPE. */
1299 lookup_conversion_operator (tree class_type
, tree type
)
1306 methods
= CLASSTYPE_METHOD_VEC (class_type
);
1308 for (pass
= 0; pass
< 2; ++pass
)
1309 for (i
= CLASSTYPE_FIRST_CONVERSION_SLOT
;
1310 VEC_iterate (tree
, methods
, i
, fn
); ++i
)
1312 /* All the conversion operators come near the beginning of the
1313 class. Therefore, if FN is not a conversion operator, there
1314 is no matching conversion operator in CLASS_TYPE. */
1315 fn
= OVL_CURRENT (fn
);
1316 if (!DECL_CONV_FN_P (fn
))
1321 /* On the first pass we only consider exact matches. If
1322 the types match, this slot is the one where the right
1323 conversion operators can be found. */
1324 if (TREE_CODE (fn
) != TEMPLATE_DECL
1325 && same_type_p (DECL_CONV_FN_TYPE (fn
), type
))
1330 /* On the second pass we look for template conversion
1331 operators. It may be possible to instantiate the
1332 template to get the type desired. All of the template
1333 conversion operators share a slot. By looking for
1334 templates second we ensure that specializations are
1335 preferred over templates. */
1336 if (TREE_CODE (fn
) == TEMPLATE_DECL
)
1344 /* TYPE is a class type. Return the index of the fields within
1345 the method vector with name NAME, or -1 is no such field exists. */
1348 lookup_fnfields_1 (tree type
, tree name
)
1350 VEC(tree
) *method_vec
;
1355 if (!CLASS_TYPE_P (type
))
1358 if (COMPLETE_TYPE_P (type
))
1360 if ((name
== ctor_identifier
1361 || name
== base_ctor_identifier
1362 || name
== complete_ctor_identifier
))
1364 if (CLASSTYPE_LAZY_DEFAULT_CTOR (type
))
1365 lazily_declare_fn (sfk_constructor
, type
);
1366 if (CLASSTYPE_LAZY_COPY_CTOR (type
))
1367 lazily_declare_fn (sfk_copy_constructor
, type
);
1369 else if (name
== ansi_assopname(NOP_EXPR
)
1370 && CLASSTYPE_LAZY_ASSIGNMENT_OP (type
))
1371 lazily_declare_fn (sfk_assignment_operator
, type
);
1374 method_vec
= CLASSTYPE_METHOD_VEC (type
);
1378 #ifdef GATHER_STATISTICS
1379 n_calls_lookup_fnfields_1
++;
1380 #endif /* GATHER_STATISTICS */
1382 /* Constructors are first... */
1383 if (name
== ctor_identifier
)
1385 fn
= CLASSTYPE_CONSTRUCTORS (type
);
1386 return fn
? CLASSTYPE_CONSTRUCTOR_SLOT
: -1;
1388 /* and destructors are second. */
1389 if (name
== dtor_identifier
)
1391 fn
= CLASSTYPE_DESTRUCTORS (type
);
1392 return fn
? CLASSTYPE_DESTRUCTOR_SLOT
: -1;
1394 if (IDENTIFIER_TYPENAME_P (name
))
1395 return lookup_conversion_operator (type
, TREE_TYPE (name
));
1397 /* Skip the conversion operators. */
1398 for (i
= CLASSTYPE_FIRST_CONVERSION_SLOT
;
1399 VEC_iterate (tree
, method_vec
, i
, fn
);
1401 if (!DECL_CONV_FN_P (OVL_CURRENT (fn
)))
1404 /* If the type is complete, use binary search. */
1405 if (COMPLETE_TYPE_P (type
))
1411 hi
= VEC_length (tree
, method_vec
);
1416 #ifdef GATHER_STATISTICS
1417 n_outer_fields_searched
++;
1418 #endif /* GATHER_STATISTICS */
1420 tmp
= VEC_index (tree
, method_vec
, i
);
1421 tmp
= DECL_NAME (OVL_CURRENT (tmp
));
1424 else if (tmp
< name
)
1431 for (; VEC_iterate (tree
, method_vec
, i
, fn
); ++i
)
1433 #ifdef GATHER_STATISTICS
1434 n_outer_fields_searched
++;
1435 #endif /* GATHER_STATISTICS */
1436 if (DECL_NAME (OVL_CURRENT (fn
)) == name
)
1443 /* DECL is the result of a qualified name lookup. QUALIFYING_SCOPE is
1444 the class or namespace used to qualify the name. CONTEXT_CLASS is
1445 the class corresponding to the object in which DECL will be used.
1446 Return a possibly modified version of DECL that takes into account
1449 In particular, consider an expression like `B::m' in the context of
1450 a derived class `D'. If `B::m' has been resolved to a BASELINK,
1451 then the most derived class indicated by the BASELINK_BINFO will be
1452 `B', not `D'. This function makes that adjustment. */
1455 adjust_result_of_qualified_name_lookup (tree decl
,
1456 tree qualifying_scope
,
1459 if (context_class
&& CLASS_TYPE_P (qualifying_scope
)
1460 && DERIVED_FROM_P (qualifying_scope
, context_class
)
1461 && BASELINK_P (decl
))
1465 my_friendly_assert (CLASS_TYPE_P (context_class
), 20020808);
1467 /* Look for the QUALIFYING_SCOPE as a base of the CONTEXT_CLASS.
1468 Because we do not yet know which function will be chosen by
1469 overload resolution, we cannot yet check either accessibility
1470 or ambiguity -- in either case, the choice of a static member
1471 function might make the usage valid. */
1472 base
= lookup_base (context_class
, qualifying_scope
,
1473 ba_ignore
| ba_quiet
, NULL
);
1476 BASELINK_ACCESS_BINFO (decl
) = base
;
1477 BASELINK_BINFO (decl
)
1478 = lookup_base (base
, BINFO_TYPE (BASELINK_BINFO (decl
)),
1479 ba_ignore
| ba_quiet
,
1488 /* Walk the class hierarchy dominated by TYPE. FN is called for each
1489 type in the hierarchy, in a breadth-first preorder traversal.
1490 If it ever returns a non-NULL value, that value is immediately
1491 returned and the walk is terminated. At each node, FN is passed a
1492 BINFO indicating the path from the currently visited base-class to
1493 TYPE. Before each base-class is walked QFN is called. If the
1494 value returned is nonzero, the base-class is walked; otherwise it
1495 is not. If QFN is NULL, it is treated as a function which always
1496 returns 1. Both FN and QFN are passed the DATA whenever they are
1499 Implementation notes: Uses a circular queue, which starts off on
1500 the stack but gets moved to the malloc arena if it needs to be
1501 enlarged. The underflow and overflow conditions are
1502 indistinguishable except by context: if head == tail and we just
1503 moved the head pointer, the queue is empty, but if we just moved
1504 the tail pointer, the queue is full.
1505 Start with enough room for ten concurrent base classes. That
1506 will be enough for most hierarchies. */
1507 #define BFS_WALK_INITIAL_QUEUE_SIZE 10
1510 bfs_walk (tree binfo
,
1511 tree (*fn
) (tree
, void *),
1512 tree (*qfn
) (tree
, int, void *),
1515 tree rval
= NULL_TREE
;
1517 tree bases_initial
[BFS_WALK_INITIAL_QUEUE_SIZE
];
1518 /* A circular queue of the base classes of BINFO. These will be
1519 built up in breadth-first order, except where QFN prunes the
1522 size_t base_buffer_size
= BFS_WALK_INITIAL_QUEUE_SIZE
;
1523 tree
*base_buffer
= bases_initial
;
1526 base_buffer
[tail
++] = binfo
;
1528 while (head
!= tail
)
1531 tree binfo
= base_buffer
[head
++];
1532 if (head
== base_buffer_size
)
1535 /* Is this the one we're looking for? If so, we're done. */
1536 rval
= fn (binfo
, data
);
1540 n_bases
= BINFO_N_BASE_BINFOS (binfo
);
1541 for (ix
= 0; ix
!= n_bases
; ix
++)
1546 base_binfo
= (*qfn
) (binfo
, ix
, data
);
1548 base_binfo
= BINFO_BASE_BINFO (binfo
, ix
);
1552 base_buffer
[tail
++] = base_binfo
;
1553 if (tail
== base_buffer_size
)
1557 tree
*new_buffer
= xmalloc (2 * base_buffer_size
1559 memcpy (&new_buffer
[0], &base_buffer
[0],
1560 tail
* sizeof (tree
));
1561 memcpy (&new_buffer
[head
+ base_buffer_size
],
1563 (base_buffer_size
- head
) * sizeof (tree
));
1564 if (base_buffer_size
!= BFS_WALK_INITIAL_QUEUE_SIZE
)
1566 base_buffer
= new_buffer
;
1567 head
+= base_buffer_size
;
1568 base_buffer_size
*= 2;
1575 if (base_buffer_size
!= BFS_WALK_INITIAL_QUEUE_SIZE
)
1580 /* Exactly like bfs_walk, except that a depth-first traversal is
1581 performed, and PREFN is called in preorder, while POSTFN is called
1585 dfs_walk_real (tree binfo
,
1586 tree (*prefn
) (tree
, void *),
1587 tree (*postfn
) (tree
, void *),
1588 tree (*qfn
) (tree
, int, void *),
1593 tree rval
= NULL_TREE
;
1595 /* Call the pre-order walking function. */
1598 rval
= (*prefn
) (binfo
, data
);
1603 /* Process the basetypes. */
1604 for (i
= 0; BINFO_BASE_ITERATE (binfo
, i
, base_binfo
); i
++)
1608 base_binfo
= (*qfn
) (binfo
, i
, data
);
1612 rval
= dfs_walk_real (base_binfo
, prefn
, postfn
, qfn
, data
);
1617 /* Call the post-order walking function. */
1619 rval
= (*postfn
) (binfo
, data
);
1624 /* Exactly like bfs_walk, except that a depth-first post-order traversal is
1628 dfs_walk (tree binfo
,
1629 tree (*fn
) (tree
, void *),
1630 tree (*qfn
) (tree
, int, void *),
1633 return dfs_walk_real (binfo
, 0, fn
, qfn
, data
);
1636 /* Check that virtual overrider OVERRIDER is acceptable for base function
1637 BASEFN. Issue diagnostic, and return zero, if unacceptable. */
1640 check_final_overrider (tree overrider
, tree basefn
)
1642 tree over_type
= TREE_TYPE (overrider
);
1643 tree base_type
= TREE_TYPE (basefn
);
1644 tree over_return
= TREE_TYPE (over_type
);
1645 tree base_return
= TREE_TYPE (base_type
);
1646 tree over_throw
= TYPE_RAISES_EXCEPTIONS (over_type
);
1647 tree base_throw
= TYPE_RAISES_EXCEPTIONS (base_type
);
1650 if (DECL_INVALID_OVERRIDER_P (overrider
))
1653 if (same_type_p (base_return
, over_return
))
1655 else if ((CLASS_TYPE_P (over_return
) && CLASS_TYPE_P (base_return
))
1656 || (TREE_CODE (base_return
) == TREE_CODE (over_return
)
1657 && POINTER_TYPE_P (base_return
)))
1659 /* Potentially covariant. */
1660 unsigned base_quals
, over_quals
;
1662 fail
= !POINTER_TYPE_P (base_return
);
1665 fail
= cp_type_quals (base_return
) != cp_type_quals (over_return
);
1667 base_return
= TREE_TYPE (base_return
);
1668 over_return
= TREE_TYPE (over_return
);
1670 base_quals
= cp_type_quals (base_return
);
1671 over_quals
= cp_type_quals (over_return
);
1673 if ((base_quals
& over_quals
) != over_quals
)
1676 if (CLASS_TYPE_P (base_return
) && CLASS_TYPE_P (over_return
))
1678 tree binfo
= lookup_base (over_return
, base_return
,
1679 ba_check
| ba_quiet
, NULL
);
1685 && can_convert (TREE_TYPE (base_type
), TREE_TYPE (over_type
)))
1686 /* GNU extension, allow trivial pointer conversions such as
1687 converting to void *, or qualification conversion. */
1689 /* can_convert will permit user defined conversion from a
1690 (reference to) class type. We must reject them. */
1691 over_return
= non_reference (TREE_TYPE (over_type
));
1692 if (CLASS_TYPE_P (over_return
))
1706 cp_error_at ("invalid covariant return type for `%#D'", overrider
);
1707 cp_error_at (" overriding `%#D'", basefn
);
1711 cp_error_at ("conflicting return type specified for `%#D'",
1713 cp_error_at (" overriding `%#D'", basefn
);
1715 DECL_INVALID_OVERRIDER_P (overrider
) = 1;
1719 /* Check throw specifier is at least as strict. */
1720 if (!comp_except_specs (base_throw
, over_throw
, 0))
1722 cp_error_at ("looser throw specifier for `%#F'", overrider
);
1723 cp_error_at (" overriding `%#F'", basefn
);
1724 DECL_INVALID_OVERRIDER_P (overrider
) = 1;
1731 /* Given a class TYPE, and a function decl FNDECL, look for
1732 virtual functions in TYPE's hierarchy which FNDECL overrides.
1733 We do not look in TYPE itself, only its bases.
1735 Returns nonzero, if we find any. Set FNDECL's DECL_VIRTUAL_P, if we
1736 find that it overrides anything.
1738 We check that every function which is overridden, is correctly
1742 look_for_overrides (tree type
, tree fndecl
)
1744 tree binfo
= TYPE_BINFO (type
);
1749 for (ix
= 0; BINFO_BASE_ITERATE (binfo
, ix
, base_binfo
); ix
++)
1751 tree basetype
= BINFO_TYPE (base_binfo
);
1753 if (TYPE_POLYMORPHIC_P (basetype
))
1754 found
+= look_for_overrides_r (basetype
, fndecl
);
1759 /* Look in TYPE for virtual functions with the same signature as
1763 look_for_overrides_here (tree type
, tree fndecl
)
1767 /* If there are no methods in TYPE (meaning that only implicitly
1768 declared methods will ever be provided for TYPE), then there are
1769 no virtual functions. */
1770 if (!CLASSTYPE_METHOD_VEC (type
))
1773 if (DECL_MAYBE_IN_CHARGE_DESTRUCTOR_P (fndecl
))
1774 ix
= CLASSTYPE_DESTRUCTOR_SLOT
;
1776 ix
= lookup_fnfields_1 (type
, DECL_NAME (fndecl
));
1779 tree fns
= VEC_index (tree
, CLASSTYPE_METHOD_VEC (type
), ix
);
1781 for (; fns
; fns
= OVL_NEXT (fns
))
1783 tree fn
= OVL_CURRENT (fns
);
1785 if (!DECL_VIRTUAL_P (fn
))
1786 /* Not a virtual. */;
1787 else if (DECL_CONTEXT (fn
) != type
)
1788 /* Introduced with a using declaration. */;
1789 else if (DECL_STATIC_FUNCTION_P (fndecl
))
1791 tree btypes
= TYPE_ARG_TYPES (TREE_TYPE (fn
));
1792 tree dtypes
= TYPE_ARG_TYPES (TREE_TYPE (fndecl
));
1793 if (compparms (TREE_CHAIN (btypes
), dtypes
))
1796 else if (same_signature_p (fndecl
, fn
))
1803 /* Look in TYPE for virtual functions overridden by FNDECL. Check both
1804 TYPE itself and its bases. */
1807 look_for_overrides_r (tree type
, tree fndecl
)
1809 tree fn
= look_for_overrides_here (type
, fndecl
);
1812 if (DECL_STATIC_FUNCTION_P (fndecl
))
1814 /* A static member function cannot match an inherited
1815 virtual member function. */
1816 cp_error_at ("`%#D' cannot be declared", fndecl
);
1817 cp_error_at (" since `%#D' declared in base class", fn
);
1821 /* It's definitely virtual, even if not explicitly set. */
1822 DECL_VIRTUAL_P (fndecl
) = 1;
1823 check_final_overrider (fndecl
, fn
);
1828 /* We failed to find one declared in this class. Look in its bases. */
1829 return look_for_overrides (type
, fndecl
);
1832 /* Called via dfs_walk from dfs_get_pure_virtuals. */
1835 dfs_get_pure_virtuals (tree binfo
, void *data
)
1837 tree type
= (tree
) data
;
1839 /* We're not interested in primary base classes; the derived class
1840 of which they are a primary base will contain the information we
1842 if (!BINFO_PRIMARY_P (binfo
))
1846 for (virtuals
= BINFO_VIRTUALS (binfo
);
1848 virtuals
= TREE_CHAIN (virtuals
))
1849 if (DECL_PURE_VIRTUAL_P (BV_FN (virtuals
)))
1850 CLASSTYPE_PURE_VIRTUALS (type
)
1851 = tree_cons (NULL_TREE
, BV_FN (virtuals
),
1852 CLASSTYPE_PURE_VIRTUALS (type
));
1855 BINFO_MARKED (binfo
) = 1;
1860 /* Set CLASSTYPE_PURE_VIRTUALS for TYPE. */
1863 get_pure_virtuals (tree type
)
1869 /* Clear the CLASSTYPE_PURE_VIRTUALS list; whatever is already there
1870 is going to be overridden. */
1871 CLASSTYPE_PURE_VIRTUALS (type
) = NULL_TREE
;
1872 /* Now, run through all the bases which are not primary bases, and
1873 collect the pure virtual functions. We look at the vtable in
1874 each class to determine what pure virtual functions are present.
1875 (A primary base is not interesting because the derived class of
1876 which it is a primary base will contain vtable entries for the
1877 pure virtuals in the base class. */
1878 dfs_walk (TYPE_BINFO (type
), dfs_get_pure_virtuals
, unmarkedp
, type
);
1879 dfs_walk (TYPE_BINFO (type
), dfs_unmark
, markedp
, type
);
1881 /* Put the pure virtuals in dfs order. */
1882 CLASSTYPE_PURE_VIRTUALS (type
) = nreverse (CLASSTYPE_PURE_VIRTUALS (type
));
1884 for (vbases
= CLASSTYPE_VBASECLASSES (type
), ix
= 0;
1885 VEC_iterate (tree
, vbases
, ix
, binfo
); ix
++)
1889 for (virtuals
= BINFO_VIRTUALS (binfo
); virtuals
;
1890 virtuals
= TREE_CHAIN (virtuals
))
1892 tree base_fndecl
= BV_FN (virtuals
);
1893 if (DECL_NEEDS_FINAL_OVERRIDER_P (base_fndecl
))
1894 error ("`%#D' needs a final overrider", base_fndecl
);
1899 /* DEPTH-FIRST SEARCH ROUTINES. */
1902 markedp (tree derived
, int ix
, void *data ATTRIBUTE_UNUSED
)
1904 tree binfo
= BINFO_BASE_BINFO (derived
, ix
);
1906 return BINFO_MARKED (binfo
) ? binfo
: NULL_TREE
;
1910 unmarkedp (tree derived
, int ix
, void *data ATTRIBUTE_UNUSED
)
1912 tree binfo
= BINFO_BASE_BINFO (derived
, ix
);
1914 return !BINFO_MARKED (binfo
) ? binfo
: NULL_TREE
;
1917 /* The worker functions for `dfs_walk'. These do not need to
1918 test anything (vis a vis marking) if they are paired with
1919 a predicate function (above). */
1922 dfs_unmark (tree binfo
, void *data ATTRIBUTE_UNUSED
)
1924 BINFO_MARKED (binfo
) = 0;
1929 /* Debug info for C++ classes can get very large; try to avoid
1930 emitting it everywhere.
1932 Note that this optimization wins even when the target supports
1933 BINCL (if only slightly), and reduces the amount of work for the
1937 maybe_suppress_debug_info (tree t
)
1939 /* We can't do the usual TYPE_DECL_SUPPRESS_DEBUG thing with DWARF, which
1940 does not support name references between translation units. It supports
1941 symbolic references between translation units, but only within a single
1942 executable or shared library.
1944 For DWARF 2, we handle TYPE_DECL_SUPPRESS_DEBUG by pretending
1945 that the type was never defined, so we only get the members we
1947 if (write_symbols
== DWARF_DEBUG
|| write_symbols
== NO_DEBUG
)
1950 /* We might have set this earlier in cp_finish_decl. */
1951 TYPE_DECL_SUPPRESS_DEBUG (TYPE_MAIN_DECL (t
)) = 0;
1953 /* If we already know how we're handling this class, handle debug info
1955 if (CLASSTYPE_INTERFACE_KNOWN (t
))
1957 if (CLASSTYPE_INTERFACE_ONLY (t
))
1958 TYPE_DECL_SUPPRESS_DEBUG (TYPE_MAIN_DECL (t
)) = 1;
1959 /* else don't set it. */
1961 /* If the class has a vtable, write out the debug info along with
1963 else if (TYPE_CONTAINS_VPTR_P (t
))
1964 TYPE_DECL_SUPPRESS_DEBUG (TYPE_MAIN_DECL (t
)) = 1;
1966 /* Otherwise, just emit the debug info normally. */
1969 /* Note that we want debugging information for a base class of a class
1970 whose vtable is being emitted. Normally, this would happen because
1971 calling the constructor for a derived class implies calling the
1972 constructors for all bases, which involve initializing the
1973 appropriate vptr with the vtable for the base class; but in the
1974 presence of optimization, this initialization may be optimized
1975 away, so we tell finish_vtable_vardecl that we want the debugging
1976 information anyway. */
1979 dfs_debug_mark (tree binfo
, void *data ATTRIBUTE_UNUSED
)
1981 tree t
= BINFO_TYPE (binfo
);
1983 CLASSTYPE_DEBUG_REQUESTED (t
) = 1;
1988 /* Returns BINFO if we haven't already noted that we want debugging
1989 info for this base class. */
1992 dfs_debug_unmarkedp (tree derived
, int ix
, void *data ATTRIBUTE_UNUSED
)
1994 tree binfo
= BINFO_BASE_BINFO (derived
, ix
);
1996 return (!CLASSTYPE_DEBUG_REQUESTED (BINFO_TYPE (binfo
))
1997 ? binfo
: NULL_TREE
);
2000 /* Write out the debugging information for TYPE, whose vtable is being
2001 emitted. Also walk through our bases and note that we want to
2002 write out information for them. This avoids the problem of not
2003 writing any debug info for intermediate basetypes whose
2004 constructors, and thus the references to their vtables, and thus
2005 the vtables themselves, were optimized away. */
2008 note_debug_info_needed (tree type
)
2010 if (TYPE_DECL_SUPPRESS_DEBUG (TYPE_NAME (type
)))
2012 TYPE_DECL_SUPPRESS_DEBUG (TYPE_NAME (type
)) = 0;
2013 rest_of_type_compilation (type
, toplevel_bindings_p ());
2016 dfs_walk (TYPE_BINFO (type
), dfs_debug_mark
, dfs_debug_unmarkedp
, 0);
2020 print_search_statistics (void)
2022 #ifdef GATHER_STATISTICS
2023 fprintf (stderr
, "%d fields searched in %d[%d] calls to lookup_field[_1]\n",
2024 n_fields_searched
, n_calls_lookup_field
, n_calls_lookup_field_1
);
2025 fprintf (stderr
, "%d fnfields searched in %d calls to lookup_fnfields\n",
2026 n_outer_fields_searched
, n_calls_lookup_fnfields
);
2027 fprintf (stderr
, "%d calls to get_base_type\n", n_calls_get_base_type
);
2028 #else /* GATHER_STATISTICS */
2029 fprintf (stderr
, "no search statistics\n");
2030 #endif /* GATHER_STATISTICS */
2034 reinit_search_statistics (void)
2036 #ifdef GATHER_STATISTICS
2037 n_fields_searched
= 0;
2038 n_calls_lookup_field
= 0, n_calls_lookup_field_1
= 0;
2039 n_calls_lookup_fnfields
= 0, n_calls_lookup_fnfields_1
= 0;
2040 n_calls_get_base_type
= 0;
2041 n_outer_fields_searched
= 0;
2042 n_contexts_saved
= 0;
2043 #endif /* GATHER_STATISTICS */
2047 add_conversions (tree binfo
, void *data
)
2050 VEC(tree
) *method_vec
= CLASSTYPE_METHOD_VEC (BINFO_TYPE (binfo
));
2051 tree
*conversions
= (tree
*) data
;
2054 /* Some builtin types have no method vector, not even an empty one. */
2058 for (i
= CLASSTYPE_FIRST_CONVERSION_SLOT
;
2059 VEC_iterate (tree
, method_vec
, i
, tmp
);
2064 if (!DECL_CONV_FN_P (OVL_CURRENT (tmp
)))
2067 name
= DECL_NAME (OVL_CURRENT (tmp
));
2069 /* Make sure we don't already have this conversion. */
2070 if (! IDENTIFIER_MARKED (name
))
2074 /* Make sure that we do not already have a conversion
2075 operator for this type. Merely checking the NAME is not
2076 enough because two conversion operators to the same type
2077 may not have the same NAME. */
2078 for (t
= *conversions
; t
; t
= TREE_CHAIN (t
))
2081 for (fn
= TREE_VALUE (t
); fn
; fn
= OVL_NEXT (fn
))
2082 if (same_type_p (TREE_TYPE (name
),
2083 DECL_CONV_FN_TYPE (OVL_CURRENT (fn
))))
2090 *conversions
= tree_cons (binfo
, tmp
, *conversions
);
2091 IDENTIFIER_MARKED (name
) = 1;
2098 /* Return a TREE_LIST containing all the non-hidden user-defined
2099 conversion functions for TYPE (and its base-classes). The
2100 TREE_VALUE of each node is a FUNCTION_DECL or an OVERLOAD
2101 containing the conversion functions. The TREE_PURPOSE is the BINFO
2102 from which the conversion functions in this node were selected. */
2105 lookup_conversions (tree type
)
2108 tree conversions
= NULL_TREE
;
2110 complete_type (type
);
2111 if (TYPE_BINFO (type
))
2112 bfs_walk (TYPE_BINFO (type
), add_conversions
, 0, &conversions
);
2114 for (t
= conversions
; t
; t
= TREE_CHAIN (t
))
2115 IDENTIFIER_MARKED (DECL_NAME (OVL_CURRENT (TREE_VALUE (t
)))) = 0;
2126 /* Check whether the empty class indicated by EMPTY_BINFO is also present
2127 at offset 0 in COMPARE_TYPE, and set found_overlap if so. */
2130 dfs_check_overlap (tree empty_binfo
, void *data
)
2132 struct overlap_info
*oi
= (struct overlap_info
*) data
;
2135 for (binfo
= TYPE_BINFO (oi
->compare_type
);
2137 binfo
= BINFO_BASE_BINFO (binfo
, 0))
2139 if (BINFO_TYPE (binfo
) == BINFO_TYPE (empty_binfo
))
2141 oi
->found_overlap
= 1;
2144 else if (!BINFO_N_BASE_BINFOS (binfo
))
2151 /* Trivial function to stop base traversal when we find something. */
2154 dfs_no_overlap_yet (tree derived
, int ix
, void *data
)
2156 tree binfo
= BINFO_BASE_BINFO (derived
, ix
);
2157 struct overlap_info
*oi
= (struct overlap_info
*) data
;
2159 return !oi
->found_overlap
? binfo
: NULL_TREE
;
2162 /* Returns nonzero if EMPTY_TYPE or any of its bases can also be found at
2163 offset 0 in NEXT_TYPE. Used in laying out empty base class subobjects. */
2166 types_overlap_p (tree empty_type
, tree next_type
)
2168 struct overlap_info oi
;
2170 if (! IS_AGGR_TYPE (next_type
))
2172 oi
.compare_type
= next_type
;
2173 oi
.found_overlap
= 0;
2174 dfs_walk (TYPE_BINFO (empty_type
), dfs_check_overlap
,
2175 dfs_no_overlap_yet
, &oi
);
2176 return oi
.found_overlap
;
2179 /* Returns the binfo of the first direct or indirect virtual base derived
2180 from BINFO, or NULL if binfo is not via virtual. */
2183 binfo_from_vbase (tree binfo
)
2185 for (; binfo
; binfo
= BINFO_INHERITANCE_CHAIN (binfo
))
2187 if (BINFO_VIRTUAL_P (binfo
))
2193 /* Returns the binfo of the first direct or indirect virtual base derived
2194 from BINFO up to the TREE_TYPE, LIMIT, or NULL if binfo is not
2198 binfo_via_virtual (tree binfo
, tree limit
)
2200 for (; binfo
&& (!limit
|| !same_type_p (BINFO_TYPE (binfo
), limit
));
2201 binfo
= BINFO_INHERITANCE_CHAIN (binfo
))
2203 if (BINFO_VIRTUAL_P (binfo
))
2209 /* BINFO is a base binfo in the complete type BINFO_TYPE (HERE).
2210 Find the equivalent binfo within whatever graph HERE is located.
2211 This is the inverse of original_binfo. */
2214 copied_binfo (tree binfo
, tree here
)
2216 tree result
= NULL_TREE
;
2218 if (BINFO_VIRTUAL_P (binfo
))
2222 for (t
= here
; BINFO_INHERITANCE_CHAIN (t
);
2223 t
= BINFO_INHERITANCE_CHAIN (t
))
2226 result
= binfo_for_vbase (BINFO_TYPE (binfo
), BINFO_TYPE (t
));
2228 else if (BINFO_INHERITANCE_CHAIN (binfo
))
2234 cbinfo
= copied_binfo (BINFO_INHERITANCE_CHAIN (binfo
), here
);
2235 for (ix
= 0; BINFO_BASE_ITERATE (cbinfo
, ix
, base_binfo
); ix
++)
2236 if (BINFO_TYPE (base_binfo
) == BINFO_TYPE (binfo
))
2238 result
= base_binfo
;
2244 my_friendly_assert (BINFO_TYPE (here
) == BINFO_TYPE (binfo
), 20030202);
2248 my_friendly_assert (result
, 20030202);
2253 binfo_for_vbase (tree base
, tree t
)
2259 for (vbases
= CLASSTYPE_VBASECLASSES (t
), ix
= 0;
2260 VEC_iterate (tree
, vbases
, ix
, binfo
); ix
++)
2261 if (BINFO_TYPE (binfo
) == base
)
2266 /* BINFO is some base binfo of HERE, within some other
2267 hierarchy. Return the equivalent binfo, but in the hierarchy
2268 dominated by HERE. This is the inverse of copied_binfo. If BINFO
2269 is not a base binfo of HERE, returns NULL_TREE. */
2272 original_binfo (tree binfo
, tree here
)
2276 if (BINFO_TYPE (binfo
) == BINFO_TYPE (here
))
2278 else if (BINFO_VIRTUAL_P (binfo
))
2279 result
= (CLASSTYPE_VBASECLASSES (BINFO_TYPE (here
))
2280 ? binfo_for_vbase (BINFO_TYPE (binfo
), BINFO_TYPE (here
))
2282 else if (BINFO_INHERITANCE_CHAIN (binfo
))
2286 base_binfos
= original_binfo (BINFO_INHERITANCE_CHAIN (binfo
), here
);
2292 for (ix
= 0; (base_binfo
= BINFO_BASE_BINFO (base_binfos
, ix
)); ix
++)
2293 if (BINFO_TYPE (base_binfo
) == BINFO_TYPE (binfo
))
2295 result
= base_binfo
;