1 /* Help friends in C++.
2 Copyright (C) 1997, 1998, 1999 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 if (type == supplicant)
107 list = CLASSTYPE_FRIEND_CLASSES (TREE_TYPE (TYPE_MAIN_DECL (type)));
108 for (; list ; list = TREE_CHAIN (list))
110 tree t = TREE_VALUE (list);
112 if (TREE_CODE (t) == TEMPLATE_DECL ?
113 is_specialization_of (TYPE_MAIN_DECL (supplicant), t) :
114 same_type_p (supplicant, t))
119 if (declp && DECL_FUNCTION_MEMBER_P (supplicant))
120 context = DECL_CLASS_CONTEXT (supplicant);
122 /* Local classes have the same access as the enclosing function. */
123 context = hack_decl_function_context (TYPE_MAIN_DECL (supplicant));
127 /* A namespace is not friend to anybody. */
128 if (context && TREE_CODE (context) == NAMESPACE_DECL)
132 return is_friend (type, context);
137 /* Add a new friend to the friends of the aggregate type TYPE.
138 DECL is the FUNCTION_DECL of the friend being added. */
141 add_friend (type, decl)
148 if (decl == error_mark_node)
151 typedecl = TYPE_MAIN_DECL (type);
152 list = DECL_FRIENDLIST (typedecl);
153 name = DECL_NAME (decl);
154 type = TREE_TYPE (typedecl);
158 if (name == FRIEND_NAME (list))
160 tree friends = FRIEND_DECLS (list);
161 for (; friends ; friends = TREE_CHAIN (friends))
163 if (decl == TREE_VALUE (friends))
165 cp_warning ("`%D' is already a friend of class `%T'",
167 cp_warning_at ("previous friend declaration of `%D'",
168 TREE_VALUE (friends));
172 TREE_VALUE (list) = tree_cons (error_mark_node, decl,
176 list = TREE_CHAIN (list);
179 DECL_FRIENDLIST (typedecl)
180 = tree_cons (DECL_NAME (decl), build_tree_list (error_mark_node, decl),
181 DECL_FRIENDLIST (typedecl));
182 if (!uses_template_parms (type))
183 DECL_BEFRIENDING_CLASSES (decl)
184 = tree_cons (NULL_TREE, type,
185 DECL_BEFRIENDING_CLASSES (decl));
188 /* Declare that every member function NAME in FRIEND_TYPE
189 (which may be NULL_TREE) is a friend of type TYPE. */
192 add_friends (type, name, friend_type)
193 tree type, name, friend_type;
195 tree typedecl = TYPE_MAIN_DECL (type);
196 tree list = DECL_FRIENDLIST (typedecl);
200 if (name == FRIEND_NAME (list))
202 tree friends = FRIEND_DECLS (list);
203 while (friends && TREE_PURPOSE (friends) != friend_type)
204 friends = TREE_CHAIN (friends);
208 warning ("method `%s::%s' is already a friend of class",
209 TYPE_NAME_STRING (friend_type),
210 IDENTIFIER_POINTER (name));
212 warning ("function `%s' is already a friend of class `%s'",
213 IDENTIFIER_POINTER (name),
214 IDENTIFIER_POINTER (DECL_NAME (typedecl)));
217 TREE_VALUE (list) = tree_cons (friend_type, NULL_TREE,
221 list = TREE_CHAIN (list);
223 DECL_FRIENDLIST (typedecl)
225 build_tree_list (friend_type, NULL_TREE),
226 DECL_FRIENDLIST (typedecl));
229 /* Make FRIEND_TYPE a friend class to TYPE. If FRIEND_TYPE has already
230 been defined, we make all of its member functions friends of
231 TYPE. If not, we make it a pending friend, which can later be added
232 when its definition is seen. If a type is defined, then its TYPE_DECL's
233 DECL_UNDEFINED_FRIENDS contains a (possibly empty) list of friend
234 classes that are not defined. If a type has not yet been defined,
235 then the DECL_WAITING_FRIENDS contains a list of types
236 waiting to make it their friend. Note that these two can both
237 be in use at the same time! */
240 make_friend_class (type, friend_type)
241 tree type, friend_type;
244 int is_template_friend;
246 if (IS_SIGNATURE (type))
248 error ("`friend' declaration in signature definition");
251 if (IS_SIGNATURE (friend_type) || ! 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)
289 A friend of a class or class template can be a function or
290 class template, a specialization of a function template or
291 class template, or an ordinary (nontemplate) function or
294 But, we're looking at something like:
296 template <class T> friend typename S<T>::X;
298 which isn't any of these. */
299 cp_error ("typename type `%T' declare `friend'",
304 GNU_xref_hier (type, friend_type, 0, 0, 1);
306 if (is_template_friend)
307 friend_type = CLASSTYPE_TI_TEMPLATE (friend_type);
309 classes = CLASSTYPE_FRIEND_CLASSES (type);
311 /* Stop if we find the same type on the list. */
312 && !(TREE_CODE (TREE_VALUE (classes)) == TEMPLATE_DECL ?
313 friend_type == TREE_VALUE (classes) :
314 same_type_p (TREE_VALUE (classes), friend_type)))
315 classes = TREE_CHAIN (classes);
317 cp_warning ("`%T' is already a friend of `%T'",
318 TREE_VALUE (classes), type);
321 CLASSTYPE_FRIEND_CLASSES (type)
322 = tree_cons (NULL_TREE, friend_type, CLASSTYPE_FRIEND_CLASSES (type));
323 if (is_template_friend)
324 friend_type = TREE_TYPE (friend_type);
325 if (!uses_template_parms (type))
326 CLASSTYPE_BEFRIENDING_CLASSES (friend_type)
327 = tree_cons (NULL_TREE, type,
328 CLASSTYPE_BEFRIENDING_CLASSES (friend_type));
332 /* Main friend processor. This is large, and for modularity purposes,
333 has been removed from grokdeclarator. It returns `void_type_node'
334 to indicate that something happened, though a FIELD_DECL is
337 CTYPE is the class this friend belongs to.
339 DECLARATOR is the name of the friend.
341 DECL is the FUNCTION_DECL that the friend is.
343 In case we are parsing a friend which is part of an inline
344 definition, we will need to store PARM_DECL chain that comes
345 with it into the DECL_ARGUMENTS slot of the FUNCTION_DECL.
347 FLAGS is just used for `grokclassfn'.
349 QUALS say what special qualifies should apply to the object
350 pointed to by `this'. */
353 do_friend (ctype, declarator, decl, parmdecls, attrlist,
354 flags, quals, funcdef_flag)
355 tree ctype, declarator, decl, parmdecls, attrlist;
356 enum overload_flags flags;
360 int is_friend_template = 0;
361 tree prefix_attributes, attributes;
363 /* Every decl that gets here is a friend of something. */
364 DECL_FRIEND_P (decl) = 1;
366 if (TREE_CODE (declarator) == TEMPLATE_ID_EXPR)
368 declarator = TREE_OPERAND (declarator, 0);
369 if (TREE_CODE (declarator) == LOOKUP_EXPR)
370 declarator = TREE_OPERAND (declarator, 0);
371 if (is_overloaded_fn (declarator))
372 declarator = DECL_NAME (get_first_fn (declarator));
375 if (TREE_CODE (decl) != FUNCTION_DECL)
376 my_friendly_abort (990513);
378 is_friend_template = PROCESSING_REAL_TEMPLATE_DECL_P ();
382 tree cname = TYPE_NAME (ctype);
383 if (TREE_CODE (cname) == TYPE_DECL)
384 cname = DECL_NAME (cname);
386 /* A method friend. */
387 if (flags == NO_SPECIAL && ctype && declarator == cname)
388 DECL_CONSTRUCTOR_P (decl) = 1;
390 /* This will set up DECL_ARGUMENTS for us. */
391 grokclassfn (ctype, decl, flags, quals);
393 if (is_friend_template)
394 decl = DECL_TI_TEMPLATE (push_template_decl (decl));
395 else if (template_class_depth (current_class_type))
396 decl = push_template_decl_real (decl, /*is_friend=*/1);
398 /* We can't do lookup in a type that involves template
399 parameters. Instead, we rely on tsubst_friend_function
400 to check the validity of the declaration later. */
401 if (uses_template_parms (ctype))
402 add_friend (current_class_type, decl);
403 /* A nested class may declare a member of an enclosing class
404 to be a friend, so we do lookup here even if CTYPE is in
405 the process of being defined. */
406 else if (TYPE_SIZE (ctype) != 0 || TYPE_BEING_DEFINED (ctype))
408 decl = check_classfn (ctype, decl);
411 add_friend (current_class_type, decl);
414 cp_error ("member `%D' declared as friend before type `%T' defined",
418 @@ or possibly a friend from a base class ?!? */
419 else if (TREE_CODE (decl) == FUNCTION_DECL)
421 /* Friends must all go through the overload machinery,
422 even though they may not technically be overloaded.
424 Note that because classes all wind up being top-level
425 in their scope, their friend wind up in top-level scope as well. */
426 DECL_ARGUMENTS (decl) = parmdecls;
428 DECL_CLASS_CONTEXT (decl) = current_class_type;
430 if (! DECL_USE_TEMPLATE (decl))
432 /* We can call pushdecl here, because the TREE_CHAIN of this
433 FUNCTION_DECL is not needed for other purposes. Don't do
434 this for a template instantiation. However, we don't
435 call pushdecl() for a friend function of a template
436 class, since in general, such a declaration depends on
437 template parameters. Instead, we call pushdecl when the
438 class is instantiated. */
439 if (!is_friend_template
440 && template_class_depth (current_class_type) == 0)
441 decl = pushdecl (decl);
443 decl = push_template_decl_real (decl, /*is_friend=*/1);
445 if (warn_nontemplate_friend
446 && ! funcdef_flag && ! flag_guiding_decls && ! is_friend_template
447 && current_template_parms && uses_template_parms (decl))
449 static int explained;
450 cp_warning ("friend declaration `%#D'", decl);
451 warning (" declares a non-template function");
454 warning (" (if this is not what you intended, make sure");
455 warning (" the function template has already been declared,");
456 warning (" and add <> after the function name here)");
457 warning (" -Wno-non-template-friend disables this warning.");
463 make_decl_rtl (decl, NULL_PTR, 1);
464 add_friend (current_class_type,
465 is_friend_template ? DECL_TI_TEMPLATE (decl) : decl);
466 DECL_FRIEND_P (decl) = 1;
469 /* Unfortunately, we have to handle attributes here. Normally we would
470 handle them in start_decl_1, but since this is a friend decl start_decl_1
471 never gets to see it. */
475 attributes = TREE_PURPOSE (attrlist);
476 prefix_attributes = TREE_VALUE (attrlist);
480 attributes = NULL_TREE;
481 prefix_attributes = NULL_TREE;
484 #ifdef SET_DEFAULT_DECL_ATTRIBUTES
485 SET_DEFAULT_DECL_ATTRIBUTES (decl, attributes);
488 /* Set attributes here so if duplicate decl, will have proper attributes. */
489 cplus_decl_attributes (decl, attributes, prefix_attributes);