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)
144 tree typedecl = TYPE_MAIN_DECL (type);
145 tree list = DECL_FRIENDLIST (typedecl);
146 tree name = DECL_NAME (decl);
148 type = TREE_TYPE (typedecl);
152 if (name == FRIEND_NAME (list))
154 tree friends = FRIEND_DECLS (list);
155 for (; friends ; friends = TREE_CHAIN (friends))
157 if (decl == TREE_VALUE (friends))
159 cp_warning ("`%D' is already a friend of class `%T'",
161 cp_warning_at ("previous friend declaration of `%D'",
162 TREE_VALUE (friends));
166 TREE_VALUE (list) = tree_cons (error_mark_node, decl,
170 list = TREE_CHAIN (list);
173 DECL_FRIENDLIST (typedecl)
174 = tree_cons (DECL_NAME (decl), build_tree_list (error_mark_node, decl),
175 DECL_FRIENDLIST (typedecl));
176 if (!uses_template_parms (type))
177 DECL_BEFRIENDING_CLASSES (decl)
178 = tree_cons (NULL_TREE, type,
179 DECL_BEFRIENDING_CLASSES (decl));
182 /* Declare that every member function NAME in FRIEND_TYPE
183 (which may be NULL_TREE) is a friend of type TYPE. */
186 add_friends (type, name, friend_type)
187 tree type, name, friend_type;
189 tree typedecl = TYPE_MAIN_DECL (type);
190 tree list = DECL_FRIENDLIST (typedecl);
194 if (name == FRIEND_NAME (list))
196 tree friends = FRIEND_DECLS (list);
197 while (friends && TREE_PURPOSE (friends) != friend_type)
198 friends = TREE_CHAIN (friends);
202 warning ("method `%s::%s' is already a friend of class",
203 TYPE_NAME_STRING (friend_type),
204 IDENTIFIER_POINTER (name));
206 warning ("function `%s' is already a friend of class `%s'",
207 IDENTIFIER_POINTER (name),
208 IDENTIFIER_POINTER (DECL_NAME (typedecl)));
211 TREE_VALUE (list) = tree_cons (friend_type, NULL_TREE,
215 list = TREE_CHAIN (list);
217 DECL_FRIENDLIST (typedecl)
219 build_tree_list (friend_type, NULL_TREE),
220 DECL_FRIENDLIST (typedecl));
223 /* Make FRIEND_TYPE a friend class to TYPE. If FRIEND_TYPE has already
224 been defined, we make all of its member functions friends of
225 TYPE. If not, we make it a pending friend, which can later be added
226 when its definition is seen. If a type is defined, then its TYPE_DECL's
227 DECL_UNDEFINED_FRIENDS contains a (possibly empty) list of friend
228 classes that are not defined. If a type has not yet been defined,
229 then the DECL_WAITING_FRIENDS contains a list of types
230 waiting to make it their friend. Note that these two can both
231 be in use at the same time! */
234 make_friend_class (type, friend_type)
235 tree type, friend_type;
238 int is_template_friend;
240 if (IS_SIGNATURE (type))
242 error ("`friend' declaration in signature definition");
245 if (IS_SIGNATURE (friend_type) || ! IS_AGGR_TYPE (friend_type))
247 cp_error ("invalid type `%T' declared `friend'", friend_type);
251 if (CLASS_TYPE_P (friend_type)
252 && CLASSTYPE_TEMPLATE_SPECIALIZATION (friend_type)
253 && uses_template_parms (friend_type))
257 Friend declarations shall not declare partial
259 cp_error ("partial specialization `%T' declared `friend'",
264 if (processing_template_decl > template_class_depth (type))
265 /* If the TYPE is a template then it makes sense for it to be
266 friends with itself; this means that each instantiation is
267 friends with all other instantiations. */
268 is_template_friend = 1;
269 else if (same_type_p (type, friend_type))
271 pedwarn ("class `%s' is implicitly friends with itself",
272 TYPE_NAME_STRING (type));
276 is_template_friend = 0;
278 GNU_xref_hier (type, friend_type, 0, 0, 1);
280 if (is_template_friend)
281 friend_type = CLASSTYPE_TI_TEMPLATE (friend_type);
283 classes = CLASSTYPE_FRIEND_CLASSES (type);
285 /* Stop if we find the same type on the list. */
286 && !(TREE_CODE (TREE_VALUE (classes)) == TEMPLATE_DECL ?
287 friend_type == TREE_VALUE (classes) :
288 same_type_p (TREE_VALUE (classes), friend_type)))
289 classes = TREE_CHAIN (classes);
291 cp_warning ("`%T' is already a friend of `%T'",
292 TREE_VALUE (classes), type);
295 CLASSTYPE_FRIEND_CLASSES (type)
296 = tree_cons (NULL_TREE, friend_type, CLASSTYPE_FRIEND_CLASSES (type));
297 if (is_template_friend)
298 friend_type = TREE_TYPE (friend_type);
299 if (!uses_template_parms (type))
300 CLASSTYPE_BEFRIENDING_CLASSES (friend_type)
301 = tree_cons (NULL_TREE, type,
302 CLASSTYPE_BEFRIENDING_CLASSES (friend_type));
306 /* Main friend processor. This is large, and for modularity purposes,
307 has been removed from grokdeclarator. It returns `void_type_node'
308 to indicate that something happened, though a FIELD_DECL is
311 CTYPE is the class this friend belongs to.
313 DECLARATOR is the name of the friend.
315 DECL is the FUNCTION_DECL that the friend is.
317 In case we are parsing a friend which is part of an inline
318 definition, we will need to store PARM_DECL chain that comes
319 with it into the DECL_ARGUMENTS slot of the FUNCTION_DECL.
321 FLAGS is just used for `grokclassfn'.
323 QUALS say what special qualifies should apply to the object
324 pointed to by `this'. */
327 do_friend (ctype, declarator, decl, parmdecls, flags, quals, funcdef_flag)
328 tree ctype, declarator, decl, parmdecls;
329 enum overload_flags flags;
333 int is_friend_template = 0;
335 /* Every decl that gets here is a friend of something. */
336 DECL_FRIEND_P (decl) = 1;
338 if (TREE_CODE (declarator) == TEMPLATE_ID_EXPR)
340 declarator = TREE_OPERAND (declarator, 0);
341 if (TREE_CODE (declarator) == LOOKUP_EXPR)
342 declarator = TREE_OPERAND (declarator, 0);
343 if (is_overloaded_fn (declarator))
344 declarator = DECL_NAME (get_first_fn (declarator));
347 if (TREE_CODE (decl) == FUNCTION_DECL)
348 is_friend_template = PROCESSING_REAL_TEMPLATE_DECL_P ();
352 tree cname = TYPE_NAME (ctype);
353 if (TREE_CODE (cname) == TYPE_DECL)
354 cname = DECL_NAME (cname);
356 /* A method friend. */
357 if (TREE_CODE (decl) == FUNCTION_DECL)
359 if (flags == NO_SPECIAL && ctype && declarator == cname)
360 DECL_CONSTRUCTOR_P (decl) = 1;
362 /* This will set up DECL_ARGUMENTS for us. */
363 grokclassfn (ctype, decl, flags, quals);
365 if (is_friend_template)
366 decl = DECL_TI_TEMPLATE (push_template_decl (decl));
367 else if (template_class_depth (current_class_type))
368 decl = push_template_decl_real (decl, /*is_friend=*/1);
370 /* We can't do lookup in a type that involves template
371 parameters. Instead, we rely on tsubst_friend_function
372 to check the validity of the declaration later. */
373 if (uses_template_parms (ctype))
374 add_friend (current_class_type, decl);
375 /* A nested class may declare a member of an enclosing class
376 to be a friend, so we do lookup here even if CTYPE is in
377 the process of being defined. */
378 else if (TYPE_SIZE (ctype) != 0 || TYPE_BEING_DEFINED (ctype))
380 decl = check_classfn (ctype, decl);
383 add_friend (current_class_type, decl);
386 cp_error ("member `%D' declared as friend before type `%T' defined",
391 /* Possibly a bunch of method friends. */
393 /* Get the class they belong to. */
394 tree ctype = IDENTIFIER_TYPE_VALUE (cname);
395 tree fields = lookup_fnfields (TYPE_BINFO (ctype), declarator, 0);
398 add_friends (current_class_type, declarator, ctype);
400 cp_error ("method `%D' is not a member of class `%T'",
402 decl = void_type_node;
406 @@ or possibly a friend from a base class ?!? */
407 else if (TREE_CODE (decl) == FUNCTION_DECL)
409 /* Friends must all go through the overload machinery,
410 even though they may not technically be overloaded.
412 Note that because classes all wind up being top-level
413 in their scope, their friend wind up in top-level scope as well. */
414 DECL_ARGUMENTS (decl) = parmdecls;
416 DECL_CLASS_CONTEXT (decl) = current_class_type;
418 if (! DECL_USE_TEMPLATE (decl))
420 /* We can call pushdecl here, because the TREE_CHAIN of this
421 FUNCTION_DECL is not needed for other purposes. Don't do
422 this for a template instantiation. However, we don't
423 call pushdecl() for a friend function of a template
424 class, since in general, such a declaration depends on
425 template parameters. Instead, we call pushdecl when the
426 class is instantiated. */
427 if (!is_friend_template
428 && template_class_depth (current_class_type) == 0)
429 decl = pushdecl (decl);
431 decl = push_template_decl_real (decl, /*is_friend=*/1);
433 if (warn_nontemplate_friend
434 && ! funcdef_flag && ! flag_guiding_decls && ! is_friend_template
435 && current_template_parms && uses_template_parms (decl))
437 static int explained;
438 cp_warning ("friend declaration `%#D'", decl);
439 warning (" declares a non-template function");
442 warning (" (if this is not what you intended, make sure");
443 warning (" the function template has already been declared,");
444 warning (" and add <> after the function name here)");
445 warning (" -Wno-non-template-friend disables this warning.");
451 make_decl_rtl (decl, NULL_PTR, 1);
452 add_friend (current_class_type,
453 is_friend_template ? DECL_TI_TEMPLATE (decl) : decl);
454 DECL_FRIEND_P (decl) = 1;
458 /* @@ Should be able to ingest later definitions of this function
460 tree decl = lookup_name_nonclass (declarator);
461 if (decl == NULL_TREE)
463 cp_warning ("implicitly declaring `%T' as struct", declarator);
464 decl = xref_tag (record_type_node, declarator, 1);
465 decl = TYPE_MAIN_DECL (decl);
468 /* Allow abbreviated declarations of overloaded functions,
469 but not if those functions are really class names. */
470 if (TREE_CODE (decl) == TREE_LIST && TREE_TYPE (TREE_PURPOSE (decl)))
472 cp_warning ("`friend %T' archaic, use `friend class %T' instead",
473 declarator, declarator);
474 decl = TREE_TYPE (TREE_PURPOSE (decl));
477 if (TREE_CODE (decl) == TREE_LIST)
478 add_friends (current_class_type, TREE_PURPOSE (decl), NULL_TREE);
480 make_friend_class (current_class_type, TREE_TYPE (decl));
481 decl = void_type_node;