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 GNU_xref_hier (type, friend_type, 0, 0, 1);
286 if (is_template_friend)
287 friend_type = CLASSTYPE_TI_TEMPLATE (friend_type);
289 classes = CLASSTYPE_FRIEND_CLASSES (type);
291 /* Stop if we find the same type on the list. */
292 && !(TREE_CODE (TREE_VALUE (classes)) == TEMPLATE_DECL ?
293 friend_type == TREE_VALUE (classes) :
294 same_type_p (TREE_VALUE (classes), friend_type)))
295 classes = TREE_CHAIN (classes);
297 cp_warning ("`%T' is already a friend of `%T'",
298 TREE_VALUE (classes), type);
301 CLASSTYPE_FRIEND_CLASSES (type)
302 = tree_cons (NULL_TREE, friend_type, CLASSTYPE_FRIEND_CLASSES (type));
303 if (is_template_friend)
304 friend_type = TREE_TYPE (friend_type);
305 if (!uses_template_parms (type))
306 CLASSTYPE_BEFRIENDING_CLASSES (friend_type)
307 = tree_cons (NULL_TREE, type,
308 CLASSTYPE_BEFRIENDING_CLASSES (friend_type));
312 /* Main friend processor. This is large, and for modularity purposes,
313 has been removed from grokdeclarator. It returns `void_type_node'
314 to indicate that something happened, though a FIELD_DECL is
317 CTYPE is the class this friend belongs to.
319 DECLARATOR is the name of the friend.
321 DECL is the FUNCTION_DECL that the friend is.
323 In case we are parsing a friend which is part of an inline
324 definition, we will need to store PARM_DECL chain that comes
325 with it into the DECL_ARGUMENTS slot of the FUNCTION_DECL.
327 FLAGS is just used for `grokclassfn'.
329 QUALS say what special qualifies should apply to the object
330 pointed to by `this'. */
333 do_friend (ctype, declarator, decl, parmdecls, flags, quals, funcdef_flag)
334 tree ctype, declarator, decl, parmdecls;
335 enum overload_flags flags;
339 int is_friend_template = 0;
341 /* Every decl that gets here is a friend of something. */
342 DECL_FRIEND_P (decl) = 1;
344 if (TREE_CODE (declarator) == TEMPLATE_ID_EXPR)
346 declarator = TREE_OPERAND (declarator, 0);
347 if (TREE_CODE (declarator) == LOOKUP_EXPR)
348 declarator = TREE_OPERAND (declarator, 0);
349 if (is_overloaded_fn (declarator))
350 declarator = DECL_NAME (get_first_fn (declarator));
353 if (TREE_CODE (decl) == FUNCTION_DECL)
354 is_friend_template = PROCESSING_REAL_TEMPLATE_DECL_P ();
358 tree cname = TYPE_NAME (ctype);
359 if (TREE_CODE (cname) == TYPE_DECL)
360 cname = DECL_NAME (cname);
362 /* A method friend. */
363 if (TREE_CODE (decl) == FUNCTION_DECL)
365 if (flags == NO_SPECIAL && ctype && declarator == cname)
366 DECL_CONSTRUCTOR_P (decl) = 1;
368 /* This will set up DECL_ARGUMENTS for us. */
369 grokclassfn (ctype, decl, flags, quals);
371 if (is_friend_template)
372 decl = DECL_TI_TEMPLATE (push_template_decl (decl));
373 else if (template_class_depth (current_class_type))
374 decl = push_template_decl_real (decl, /*is_friend=*/1);
376 /* We can't do lookup in a type that involves template
377 parameters. Instead, we rely on tsubst_friend_function
378 to check the validity of the declaration later. */
379 if (uses_template_parms (ctype))
380 add_friend (current_class_type, decl);
381 /* A nested class may declare a member of an enclosing class
382 to be a friend, so we do lookup here even if CTYPE is in
383 the process of being defined. */
384 else if (TYPE_SIZE (ctype) != 0 || TYPE_BEING_DEFINED (ctype))
386 decl = check_classfn (ctype, decl);
389 add_friend (current_class_type, decl);
392 cp_error ("member `%D' declared as friend before type `%T' defined",
397 /* Possibly a bunch of method friends. */
399 /* Get the class they belong to. */
400 tree ctype = IDENTIFIER_TYPE_VALUE (cname);
401 tree fields = lookup_fnfields (TYPE_BINFO (ctype), declarator, 0);
404 add_friends (current_class_type, declarator, ctype);
406 cp_error ("method `%D' is not a member of class `%T'",
408 decl = void_type_node;
412 @@ or possibly a friend from a base class ?!? */
413 else if (TREE_CODE (decl) == FUNCTION_DECL)
415 /* Friends must all go through the overload machinery,
416 even though they may not technically be overloaded.
418 Note that because classes all wind up being top-level
419 in their scope, their friend wind up in top-level scope as well. */
420 DECL_ARGUMENTS (decl) = parmdecls;
422 DECL_CLASS_CONTEXT (decl) = current_class_type;
424 if (! DECL_USE_TEMPLATE (decl))
426 /* We can call pushdecl here, because the TREE_CHAIN of this
427 FUNCTION_DECL is not needed for other purposes. Don't do
428 this for a template instantiation. However, we don't
429 call pushdecl() for a friend function of a template
430 class, since in general, such a declaration depends on
431 template parameters. Instead, we call pushdecl when the
432 class is instantiated. */
433 if (!is_friend_template
434 && template_class_depth (current_class_type) == 0)
435 decl = pushdecl (decl);
437 decl = push_template_decl_real (decl, /*is_friend=*/1);
439 if (warn_nontemplate_friend
440 && ! funcdef_flag && ! flag_guiding_decls && ! is_friend_template
441 && current_template_parms && uses_template_parms (decl))
443 static int explained;
444 cp_warning ("friend declaration `%#D'", decl);
445 warning (" declares a non-template function");
448 warning (" (if this is not what you intended, make sure");
449 warning (" the function template has already been declared,");
450 warning (" and add <> after the function name here)");
451 warning (" -Wno-non-template-friend disables this warning.");
457 make_decl_rtl (decl, NULL_PTR, 1);
458 add_friend (current_class_type,
459 is_friend_template ? DECL_TI_TEMPLATE (decl) : decl);
460 DECL_FRIEND_P (decl) = 1;
464 /* @@ Should be able to ingest later definitions of this function
466 tree decl = lookup_name_nonclass (declarator);
467 if (decl == NULL_TREE)
469 cp_warning ("implicitly declaring `%T' as struct", declarator);
470 decl = xref_tag (record_type_node, declarator, 1);
471 decl = TYPE_MAIN_DECL (decl);
474 /* Allow abbreviated declarations of overloaded functions,
475 but not if those functions are really class names. */
476 if (TREE_CODE (decl) == TREE_LIST && TREE_TYPE (TREE_PURPOSE (decl)))
478 cp_warning ("`friend %T' archaic, use `friend class %T' instead",
479 declarator, declarator);
480 decl = TREE_TYPE (TREE_PURPOSE (decl));
483 if (TREE_CODE (decl) == TREE_LIST)
484 add_friends (current_class_type, TREE_PURPOSE (decl), NULL_TREE);
486 make_friend_class (current_class_type, TREE_TYPE (decl));
487 decl = void_type_node;