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_AGGR_TYPE (friend_type))
248 cp_error ("invalid type `%T' declared `friend'", friend_type);
252 if (CLASS_TYPE_P (friend_type)
253 && CLASSTYPE_TEMPLATE_SPECIALIZATION (friend_type)
254 && uses_template_parms (friend_type))
258 Friend declarations shall not declare partial
260 cp_error ("partial specialization `%T' declared `friend'",
265 if (processing_template_decl > template_class_depth (type))
266 /* If the TYPE is a template then it makes sense for it to be
267 friends with itself; this means that each instantiation is
268 friends with all other instantiations. */
269 is_template_friend = 1;
270 else if (same_type_p (type, friend_type))
272 pedwarn ("class `%s' is implicitly friends with itself",
273 TYPE_NAME_STRING (type));
277 is_template_friend = 0;
279 if (is_template_friend
280 && (TREE_CODE (friend_type) == TYPENAME_TYPE
281 || TREE_CODE (friend_type) == TEMPLATE_TYPE_PARM))
285 A friend of a class or class template can be a function or
286 class template, a specialization of a function template or
287 class template, or an ordinary (nontemplate) function or
290 But, we're looking at something like:
292 template <class T> friend typename S<T>::X;
296 template <class T> friend class T;
298 which isn't any of these. */
299 if (TREE_CODE (friend_type) == TYPENAME_TYPE)
300 cp_error ("typename type `%T' declared `friend'",
303 cp_error ("template parameter type `%T' declared `friend'",
308 GNU_xref_hier (type, friend_type, 0, 0, 1);
310 if (is_template_friend)
311 friend_type = CLASSTYPE_TI_TEMPLATE (friend_type);
313 classes = CLASSTYPE_FRIEND_CLASSES (type);
315 /* Stop if we find the same type on the list. */
316 && !(TREE_CODE (TREE_VALUE (classes)) == TEMPLATE_DECL ?
317 friend_type == TREE_VALUE (classes) :
318 same_type_p (TREE_VALUE (classes), friend_type)))
319 classes = TREE_CHAIN (classes);
321 cp_warning ("`%T' is already a friend of `%T'",
322 TREE_VALUE (classes), type);
325 CLASSTYPE_FRIEND_CLASSES (type)
326 = tree_cons (NULL_TREE, friend_type, CLASSTYPE_FRIEND_CLASSES (type));
327 if (is_template_friend)
328 friend_type = TREE_TYPE (friend_type);
329 if (!uses_template_parms (type))
330 CLASSTYPE_BEFRIENDING_CLASSES (friend_type)
331 = tree_cons (NULL_TREE, type,
332 CLASSTYPE_BEFRIENDING_CLASSES (friend_type));
336 /* Main friend processor. This is large, and for modularity purposes,
337 has been removed from grokdeclarator. It returns `void_type_node'
338 to indicate that something happened, though a FIELD_DECL is
341 CTYPE is the class this friend belongs to.
343 DECLARATOR is the name of the friend.
345 DECL is the FUNCTION_DECL that the friend is.
347 In case we are parsing a friend which is part of an inline
348 definition, we will need to store PARM_DECL chain that comes
349 with it into the DECL_ARGUMENTS slot of the FUNCTION_DECL.
351 FLAGS is just used for `grokclassfn'.
353 QUALS say what special qualifies should apply to the object
354 pointed to by `this'. */
357 do_friend (ctype, declarator, decl, parmdecls, attrlist,
358 flags, quals, funcdef_flag)
359 tree ctype, declarator, decl, parmdecls, attrlist;
360 enum overload_flags flags;
364 int is_friend_template = 0;
365 tree prefix_attributes, attributes;
367 /* Every decl that gets here is a friend of something. */
368 DECL_FRIEND_P (decl) = 1;
370 if (TREE_CODE (declarator) == TEMPLATE_ID_EXPR)
372 declarator = TREE_OPERAND (declarator, 0);
373 if (TREE_CODE (declarator) == LOOKUP_EXPR)
374 declarator = TREE_OPERAND (declarator, 0);
375 if (is_overloaded_fn (declarator))
376 declarator = DECL_NAME (get_first_fn (declarator));
379 if (TREE_CODE (decl) != FUNCTION_DECL)
380 my_friendly_abort (990513);
382 is_friend_template = PROCESSING_REAL_TEMPLATE_DECL_P ();
386 tree cname = TYPE_NAME (ctype);
387 if (TREE_CODE (cname) == TYPE_DECL)
388 cname = DECL_NAME (cname);
390 /* A method friend. */
391 if (flags == NO_SPECIAL && ctype && declarator == cname)
392 DECL_CONSTRUCTOR_P (decl) = 1;
394 /* This will set up DECL_ARGUMENTS for us. */
395 grokclassfn (ctype, decl, flags, quals);
397 if (is_friend_template)
398 decl = DECL_TI_TEMPLATE (push_template_decl (decl));
399 else if (template_class_depth (current_class_type))
400 decl = push_template_decl_real (decl, /*is_friend=*/1);
402 /* We can't do lookup in a type that involves template
403 parameters. Instead, we rely on tsubst_friend_function
404 to check the validity of the declaration later. */
405 if (uses_template_parms (ctype))
406 add_friend (current_class_type, decl);
407 /* A nested class may declare a member of an enclosing class
408 to be a friend, so we do lookup here even if CTYPE is in
409 the process of being defined. */
410 else if (TYPE_SIZE (ctype) != 0 || TYPE_BEING_DEFINED (ctype))
412 decl = check_classfn (ctype, decl);
415 add_friend (current_class_type, decl);
418 cp_error ("member `%D' declared as friend before type `%T' defined",
422 @@ or possibly a friend from a base class ?!? */
423 else if (TREE_CODE (decl) == FUNCTION_DECL)
425 /* Friends must all go through the overload machinery,
426 even though they may not technically be overloaded.
428 Note that because classes all wind up being top-level
429 in their scope, their friend wind up in top-level scope as well. */
430 DECL_ARGUMENTS (decl) = parmdecls;
432 DECL_CLASS_CONTEXT (decl) = current_class_type;
434 if (! DECL_USE_TEMPLATE (decl))
436 /* We can call pushdecl here, because the TREE_CHAIN of this
437 FUNCTION_DECL is not needed for other purposes. Don't do
438 this for a template instantiation. However, we don't
439 call pushdecl() for a friend function of a template
440 class, since in general, such a declaration depends on
441 template parameters. Instead, we call pushdecl when the
442 class is instantiated. */
443 if (!is_friend_template
444 && template_class_depth (current_class_type) == 0)
445 decl = pushdecl (decl);
447 decl = push_template_decl_real (decl, /*is_friend=*/1);
449 if (warn_nontemplate_friend
450 && ! funcdef_flag && ! flag_guiding_decls && ! is_friend_template
451 && current_template_parms && uses_template_parms (decl))
453 static int explained;
454 cp_warning ("friend declaration `%#D'", decl);
455 warning (" declares a non-template function");
458 warning (" (if this is not what you intended, make sure");
459 warning (" the function template has already been declared,");
460 warning (" and add <> after the function name here)");
461 warning (" -Wno-non-template-friend disables this warning.");
467 make_decl_rtl (decl, NULL_PTR, 1);
468 add_friend (current_class_type,
469 is_friend_template ? DECL_TI_TEMPLATE (decl) : decl);
470 DECL_FRIEND_P (decl) = 1;
473 /* Unfortunately, we have to handle attributes here. Normally we would
474 handle them in start_decl_1, but since this is a friend decl start_decl_1
475 never gets to see it. */
479 attributes = TREE_PURPOSE (attrlist);
480 prefix_attributes = TREE_VALUE (attrlist);
484 attributes = NULL_TREE;
485 prefix_attributes = NULL_TREE;
488 #ifdef SET_DEFAULT_DECL_ATTRIBUTES
489 SET_DEFAULT_DECL_ATTRIBUTES (decl, attributes);
492 /* Set attributes here so if duplicate decl, will have proper attributes. */
493 cplus_decl_attributes (decl, attributes, prefix_attributes);