1 /* Help friends in C++.
2 Copyright (C) 1997, 1998, 1999, 2000 Free Software Foundation, Inc.
4 This file is part of GNU CC.
6 GNU CC is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 2, or (at your option)
11 GNU CC is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with GNU CC; see the file COPYING. If not, write to
18 the Free Software Foundation, 59 Temple Place - Suite 330,
19 Boston, MA 02111-1307, USA. */
30 /* Friend data structures are described in cp-tree.h. */
32 /* Returns non-zero if SUPPLICANT is a friend of TYPE. */
35 is_friend (type, supplicant)
36 tree type, supplicant;
42 if (supplicant == NULL_TREE || type == NULL_TREE)
45 declp = (TREE_CODE_CLASS (TREE_CODE (supplicant)) == 'd');
48 /* It's a function decl. */
50 tree list = DECL_FRIENDLIST (TYPE_MAIN_DECL (type));
51 tree name = DECL_NAME (supplicant);
54 if (DECL_FUNCTION_MEMBER_P (supplicant))
55 ctype = DECL_CLASS_CONTEXT (supplicant);
59 for (; list ; list = TREE_CHAIN (list))
61 if (name == FRIEND_NAME (list))
63 tree friends = FRIEND_DECLS (list);
64 for (; friends ; friends = TREE_CHAIN (friends))
66 if (same_type_p (ctype, TREE_PURPOSE (friends)))
69 if (TREE_VALUE (friends) == NULL_TREE)
72 if (supplicant == TREE_VALUE (friends))
75 /* With -fguiding-decls we are more lenient about
76 friendship. This is bogus in general since two
77 specializations of a template with non-type
78 template parameters may have the same type, but
81 Temporarily, we are also more lenient to deal
82 with nested friend functions, for which there can
83 be more than one FUNCTION_DECL, despite being the
84 same function. When that's fixed, the
85 FUNCTION_MEMBER_P bit can go. */
86 if ((flag_guiding_decls
87 || DECL_FUNCTION_MEMBER_P (supplicant))
88 && same_type_p (TREE_TYPE (supplicant),
89 TREE_TYPE (TREE_VALUE (friends))))
92 if (TREE_CODE (TREE_VALUE (friends)) == TEMPLATE_DECL
93 && is_specialization_of (supplicant,
94 TREE_VALUE (friends)))
104 /* The type and its nested classes are implicitly friends, as
105 per core issue 45 (this is a change from the standard). */
106 for (context = supplicant;
107 context && TYPE_P (context);
108 context = TYPE_CONTEXT (context))
112 list = CLASSTYPE_FRIEND_CLASSES (TREE_TYPE (TYPE_MAIN_DECL (type)));
113 for (; list ; list = TREE_CHAIN (list))
115 tree t = TREE_VALUE (list);
117 if (TREE_CODE (t) == TEMPLATE_DECL ?
118 is_specialization_of (TYPE_MAIN_DECL (supplicant), t) :
119 same_type_p (supplicant, t))
124 if (declp && DECL_FUNCTION_MEMBER_P (supplicant))
125 context = DECL_CLASS_CONTEXT (supplicant);
127 /* Local classes have the same access as the enclosing function. */
128 context = hack_decl_function_context (TYPE_MAIN_DECL (supplicant));
132 /* A namespace is not friend to anybody. */
133 if (context && TREE_CODE (context) == NAMESPACE_DECL)
137 return is_friend (type, context);
142 /* Add a new friend to the friends of the aggregate type TYPE.
143 DECL is the FUNCTION_DECL of the friend being added. */
146 add_friend (type, decl)
153 if (decl == error_mark_node)
156 typedecl = TYPE_MAIN_DECL (type);
157 list = DECL_FRIENDLIST (typedecl);
158 name = DECL_NAME (decl);
159 type = TREE_TYPE (typedecl);
163 if (name == FRIEND_NAME (list))
165 tree friends = FRIEND_DECLS (list);
166 for (; friends ; friends = TREE_CHAIN (friends))
168 if (decl == TREE_VALUE (friends))
170 cp_warning ("`%D' is already a friend of class `%T'",
172 cp_warning_at ("previous friend declaration of `%D'",
173 TREE_VALUE (friends));
177 TREE_VALUE (list) = tree_cons (error_mark_node, decl,
181 list = TREE_CHAIN (list);
184 DECL_FRIENDLIST (typedecl)
185 = tree_cons (DECL_NAME (decl), build_tree_list (error_mark_node, decl),
186 DECL_FRIENDLIST (typedecl));
187 if (!uses_template_parms (type))
188 DECL_BEFRIENDING_CLASSES (decl)
189 = tree_cons (NULL_TREE, type,
190 DECL_BEFRIENDING_CLASSES (decl));
193 /* Declare that every member function NAME in FRIEND_TYPE
194 (which may be NULL_TREE) is a friend of type TYPE. */
197 add_friends (type, name, friend_type)
198 tree type, name, friend_type;
200 tree typedecl = TYPE_MAIN_DECL (type);
201 tree list = DECL_FRIENDLIST (typedecl);
205 if (name == FRIEND_NAME (list))
207 tree friends = FRIEND_DECLS (list);
208 while (friends && TREE_PURPOSE (friends) != friend_type)
209 friends = TREE_CHAIN (friends);
213 warning ("method `%s::%s' is already a friend of class",
214 TYPE_NAME_STRING (friend_type),
215 IDENTIFIER_POINTER (name));
217 warning ("function `%s' is already a friend of class `%s'",
218 IDENTIFIER_POINTER (name),
219 IDENTIFIER_POINTER (DECL_NAME (typedecl)));
222 TREE_VALUE (list) = tree_cons (friend_type, NULL_TREE,
226 list = TREE_CHAIN (list);
228 DECL_FRIENDLIST (typedecl)
230 build_tree_list (friend_type, NULL_TREE),
231 DECL_FRIENDLIST (typedecl));
234 /* Make FRIEND_TYPE a friend class to TYPE. If FRIEND_TYPE has already
235 been defined, we make all of its member functions friends of
236 TYPE. If not, we make it a pending friend, which can later be added
237 when its definition is seen. If a type is defined, then its TYPE_DECL's
238 DECL_UNDEFINED_FRIENDS contains a (possibly empty) list of friend
239 classes that are not defined. If a type has not yet been defined,
240 then the DECL_WAITING_FRIENDS contains a list of types
241 waiting to make it their friend. Note that these two can both
242 be in use at the same time! */
245 make_friend_class (type, friend_type)
246 tree type, friend_type;
249 int is_template_friend;
251 if (! IS_AGGR_TYPE (friend_type))
253 cp_error ("invalid type `%T' declared `friend'", friend_type);
257 if (CLASS_TYPE_P (friend_type)
258 && CLASSTYPE_TEMPLATE_SPECIALIZATION (friend_type)
259 && uses_template_parms (friend_type))
263 Friend declarations shall not declare partial
265 cp_error ("partial specialization `%T' declared `friend'",
270 if (processing_template_decl > template_class_depth (type))
271 /* If the TYPE is a template then it makes sense for it to be
272 friends with itself; this means that each instantiation is
273 friends with all other instantiations. */
274 is_template_friend = 1;
275 else if (same_type_p (type, friend_type))
277 pedwarn ("class `%s' is implicitly friends with itself",
278 TYPE_NAME_STRING (type));
282 is_template_friend = 0;
284 if (is_template_friend
285 && (TREE_CODE (friend_type) == TYPENAME_TYPE
286 || TREE_CODE (friend_type) == TEMPLATE_TYPE_PARM))
290 A friend of a class or class template can be a function or
291 class template, a specialization of a function template or
292 class template, or an ordinary (nontemplate) function or
295 But, we're looking at something like:
297 template <class T> friend typename S<T>::X;
301 template <class T> friend class T;
303 which isn't any of these. */
304 if (TREE_CODE (friend_type) == TYPENAME_TYPE)
305 cp_error ("typename type `%T' declared `friend'",
308 cp_error ("template parameter type `%T' declared `friend'",
313 GNU_xref_hier (type, friend_type, 0, 0, 1);
315 if (is_template_friend)
316 friend_type = CLASSTYPE_TI_TEMPLATE (friend_type);
318 classes = CLASSTYPE_FRIEND_CLASSES (type);
320 /* Stop if we find the same type on the list. */
321 && !(TREE_CODE (TREE_VALUE (classes)) == TEMPLATE_DECL ?
322 friend_type == TREE_VALUE (classes) :
323 same_type_p (TREE_VALUE (classes), friend_type)))
324 classes = TREE_CHAIN (classes);
326 cp_warning ("`%T' is already a friend of `%T'",
327 TREE_VALUE (classes), type);
330 CLASSTYPE_FRIEND_CLASSES (type)
331 = tree_cons (NULL_TREE, friend_type, CLASSTYPE_FRIEND_CLASSES (type));
332 if (is_template_friend)
333 friend_type = TREE_TYPE (friend_type);
334 if (!uses_template_parms (type))
335 CLASSTYPE_BEFRIENDING_CLASSES (friend_type)
336 = tree_cons (NULL_TREE, type,
337 CLASSTYPE_BEFRIENDING_CLASSES (friend_type));
341 /* Main friend processor. This is large, and for modularity purposes,
342 has been removed from grokdeclarator. It returns `void_type_node'
343 to indicate that something happened, though a FIELD_DECL is
346 CTYPE is the class this friend belongs to.
348 DECLARATOR is the name of the friend.
350 DECL is the FUNCTION_DECL that the friend is.
352 In case we are parsing a friend which is part of an inline
353 definition, we will need to store PARM_DECL chain that comes
354 with it into the DECL_ARGUMENTS slot of the FUNCTION_DECL.
356 FLAGS is just used for `grokclassfn'.
358 QUALS say what special qualifies should apply to the object
359 pointed to by `this'. */
362 do_friend (ctype, declarator, decl, parmdecls, attrlist,
363 flags, quals, funcdef_flag)
364 tree ctype, declarator, decl, parmdecls, attrlist;
365 enum overload_flags flags;
369 int is_friend_template = 0;
370 tree prefix_attributes, attributes;
372 /* Every decl that gets here is a friend of something. */
373 DECL_FRIEND_P (decl) = 1;
375 if (TREE_CODE (declarator) == TEMPLATE_ID_EXPR)
377 declarator = TREE_OPERAND (declarator, 0);
378 if (TREE_CODE (declarator) == LOOKUP_EXPR)
379 declarator = TREE_OPERAND (declarator, 0);
380 if (is_overloaded_fn (declarator))
381 declarator = DECL_NAME (get_first_fn (declarator));
384 if (TREE_CODE (decl) != FUNCTION_DECL)
385 my_friendly_abort (990513);
387 is_friend_template = PROCESSING_REAL_TEMPLATE_DECL_P ();
391 tree cname = TYPE_NAME (ctype);
392 if (TREE_CODE (cname) == TYPE_DECL)
393 cname = DECL_NAME (cname);
395 /* A method friend. */
396 if (flags == NO_SPECIAL && ctype && declarator == cname)
397 DECL_CONSTRUCTOR_P (decl) = 1;
399 /* This will set up DECL_ARGUMENTS for us. */
400 grokclassfn (ctype, decl, flags, quals);
402 if (is_friend_template)
403 decl = DECL_TI_TEMPLATE (push_template_decl (decl));
404 else if (template_class_depth (current_class_type))
405 decl = push_template_decl_real (decl, /*is_friend=*/1);
407 /* We can't do lookup in a type that involves template
408 parameters. Instead, we rely on tsubst_friend_function
409 to check the validity of the declaration later. */
410 if (processing_template_decl)
411 add_friend (current_class_type, decl);
412 /* A nested class may declare a member of an enclosing class
413 to be a friend, so we do lookup here even if CTYPE is in
414 the process of being defined. */
415 else if (TYPE_SIZE (ctype) != 0 || TYPE_BEING_DEFINED (ctype))
417 decl = check_classfn (ctype, decl);
420 add_friend (current_class_type, decl);
423 cp_error ("member `%D' declared as friend before type `%T' defined",
427 @@ or possibly a friend from a base class ?!? */
428 else if (TREE_CODE (decl) == FUNCTION_DECL)
430 /* Friends must all go through the overload machinery,
431 even though they may not technically be overloaded.
433 Note that because classes all wind up being top-level
434 in their scope, their friend wind up in top-level scope as well. */
435 DECL_ARGUMENTS (decl) = parmdecls;
437 DECL_CLASS_CONTEXT (decl) = current_class_type;
439 if (! DECL_USE_TEMPLATE (decl))
441 /* We can call pushdecl here, because the TREE_CHAIN of this
442 FUNCTION_DECL is not needed for other purposes. Don't do
443 this for a template instantiation. However, we don't
444 call pushdecl() for a friend function of a template
445 class, since in general, such a declaration depends on
446 template parameters. Instead, we call pushdecl when the
447 class is instantiated. */
448 if (!is_friend_template
449 && template_class_depth (current_class_type) == 0)
450 decl = pushdecl (decl);
452 decl = push_template_decl_real (decl, /*is_friend=*/1);
454 if (warn_nontemplate_friend
455 && ! funcdef_flag && ! flag_guiding_decls && ! is_friend_template
456 && current_template_parms && uses_template_parms (decl))
458 static int explained;
459 cp_warning ("friend declaration `%#D'", decl);
460 warning (" declares a non-template function");
463 warning (" (if this is not what you intended, make sure");
464 warning (" the function template has already been declared,");
465 warning (" and add <> after the function name here)");
466 warning (" -Wno-non-template-friend disables this warning.");
472 make_decl_rtl (decl, NULL_PTR, 1);
473 add_friend (current_class_type,
474 is_friend_template ? DECL_TI_TEMPLATE (decl) : decl);
475 DECL_FRIEND_P (decl) = 1;
478 /* Unfortunately, we have to handle attributes here. Normally we would
479 handle them in start_decl_1, but since this is a friend decl start_decl_1
480 never gets to see it. */
484 attributes = TREE_PURPOSE (attrlist);
485 prefix_attributes = TREE_VALUE (attrlist);
489 attributes = NULL_TREE;
490 prefix_attributes = NULL_TREE;
493 #ifdef SET_DEFAULT_DECL_ATTRIBUTES
494 SET_DEFAULT_DECL_ATTRIBUTES (decl, attributes);
497 /* Set attributes here so if duplicate decl, will have proper attributes. */
498 cplus_decl_attributes (decl, attributes, prefix_attributes);