1 /* Help friends in C++.
2 Copyright (C) 1997, 1998 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 static void add_friend PROTO((tree, tree));
31 static void add_friends PROTO((tree, tree, tree));
33 /* Friend data structures are described in cp-tree.h. */
36 is_friend (type, supplicant)
37 tree type, supplicant;
43 if (supplicant == NULL_TREE || type == NULL_TREE)
46 declp = (TREE_CODE_CLASS (TREE_CODE (supplicant)) == 'd');
49 /* It's a function decl. */
51 tree list = DECL_FRIENDLIST (TYPE_MAIN_DECL (type));
52 tree name = DECL_NAME (supplicant);
55 if (DECL_FUNCTION_MEMBER_P (supplicant))
56 ctype = DECL_CLASS_CONTEXT (supplicant);
60 for (; list ; list = TREE_CHAIN (list))
62 if (name == TREE_PURPOSE (list))
64 tree friends = TREE_VALUE (list);
65 for (; friends ; friends = TREE_CHAIN (friends))
67 if (same_type_p (ctype, TREE_PURPOSE (friends)))
70 if (TREE_VALUE (friends) == NULL_TREE)
73 if (supplicant == TREE_VALUE (friends))
76 /* With -fguiding-decls we are more lenient about
77 friendship. This is bogus in general since two
78 specializations of a template with non-type
79 template parameters may have the same type, but
82 Temporarily, we are also more lenient to deal
83 with nested friend functions, for which there can
84 be more than one FUNCTION_DECL, despite being the
85 same function. When that's fixed, the
86 FUNCTION_MEMBER_P bit can go. */
87 if ((flag_guiding_decls
88 || DECL_FUNCTION_MEMBER_P (supplicant))
89 && same_type_p (TREE_TYPE (supplicant),
90 TREE_TYPE (TREE_VALUE (friends))))
93 if (TREE_CODE (TREE_VALUE (friends)) == TEMPLATE_DECL
94 && is_specialization_of (supplicant,
95 TREE_VALUE (friends)))
105 if (type == supplicant)
108 list = CLASSTYPE_FRIEND_CLASSES (TREE_TYPE (TYPE_MAIN_DECL (type)));
109 for (; list ; list = TREE_CHAIN (list))
111 tree t = TREE_VALUE (list);
113 if (TREE_CODE (t) == TEMPLATE_DECL ?
114 is_specialization_of (TYPE_MAIN_DECL (supplicant), t) :
115 same_type_p (supplicant, t))
120 if (declp && DECL_FUNCTION_MEMBER_P (supplicant))
121 context = DECL_CLASS_CONTEXT (supplicant);
123 /* Local classes have the same access as the enclosing function. */
124 context = hack_decl_function_context (TYPE_MAIN_DECL (supplicant));
128 /* A namespace is not friend to anybody. */
129 if (context && TREE_CODE (context) == NAMESPACE_DECL)
133 return is_friend (type, context);
138 /* Add a new friend to the friends of the aggregate type TYPE.
139 DECL is the FUNCTION_DECL of the friend being added. */
142 add_friend (type, decl)
145 tree typedecl = TYPE_MAIN_DECL (type);
146 tree list = DECL_FRIENDLIST (typedecl);
147 tree name = DECL_NAME (decl);
151 if (name == TREE_PURPOSE (list))
153 tree friends = TREE_VALUE (list);
154 for (; friends ; friends = TREE_CHAIN (friends))
156 if (decl == TREE_VALUE (friends))
158 cp_warning ("`%D' is already a friend of class `%T'",
160 cp_warning_at ("previous friend declaration of `%D'",
161 TREE_VALUE (friends));
165 TREE_VALUE (list) = tree_cons (error_mark_node, decl,
169 list = TREE_CHAIN (list);
171 DECL_FRIENDLIST (typedecl)
172 = tree_cons (DECL_NAME (decl), build_tree_list (error_mark_node, decl),
173 DECL_FRIENDLIST (typedecl));
174 if (DECL_NAME (decl) == ansi_opname[(int) MODIFY_EXPR])
176 tree parmtypes = TYPE_ARG_TYPES (TREE_TYPE (decl));
177 TYPE_HAS_ASSIGNMENT (TREE_TYPE (typedecl)) = 1;
178 if (parmtypes && TREE_CHAIN (parmtypes))
180 tree parmtype = TREE_VALUE (TREE_CHAIN (parmtypes));
181 if (TREE_CODE (parmtype) == REFERENCE_TYPE
182 && TREE_TYPE (parmtypes) == TREE_TYPE (typedecl))
183 TYPE_HAS_ASSIGN_REF (TREE_TYPE (typedecl)) = 1;
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 == TREE_PURPOSE (list))
202 tree friends = TREE_VALUE (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));
227 if (! strncmp (IDENTIFIER_POINTER (name),
228 IDENTIFIER_POINTER (ansi_opname[(int) MODIFY_EXPR]),
229 strlen (IDENTIFIER_POINTER (ansi_opname[(int) MODIFY_EXPR]))))
231 TYPE_HAS_ASSIGNMENT (TREE_TYPE (typedecl)) = 1;
232 sorry ("declaring \"friend operator =\" will not find \"operator = (X&)\" if it exists");
236 /* Make FRIEND_TYPE a friend class to TYPE. If FRIEND_TYPE has already
237 been defined, we make all of its member functions friends of
238 TYPE. If not, we make it a pending friend, which can later be added
239 when its definition is seen. If a type is defined, then its TYPE_DECL's
240 DECL_UNDEFINED_FRIENDS contains a (possibly empty) list of friend
241 classes that are not defined. If a type has not yet been defined,
242 then the DECL_WAITING_FRIENDS contains a list of types
243 waiting to make it their friend. Note that these two can both
244 be in use at the same time! */
247 make_friend_class (type, friend_type)
248 tree type, friend_type;
251 int is_template_friend;
253 if (IS_SIGNATURE (type))
255 error ("`friend' declaration in signature definition");
258 if (IS_SIGNATURE (friend_type) || ! IS_AGGR_TYPE (friend_type))
260 cp_error ("invalid type `%T' declared `friend'", friend_type);
264 if (CLASSTYPE_TEMPLATE_SPECIALIZATION (friend_type)
265 && uses_template_parms (friend_type))
269 Friend declarations shall not declare partial
271 cp_error ("partial specialization `%T' declared `friend'",
276 if (processing_template_decl > template_class_depth (type))
277 /* If the TYPE is a template then it makes sense for it to be
278 friends with itself; this means that each instantiation is
279 friends with all other instantiations. */
280 is_template_friend = 1;
281 else if (same_type_p (type, friend_type))
283 pedwarn ("class `%s' is implicitly friends with itself",
284 TYPE_NAME_STRING (type));
288 is_template_friend = 0;
290 GNU_xref_hier (type, friend_type, 0, 0, 1);
292 if (is_template_friend)
293 friend_type = CLASSTYPE_TI_TEMPLATE (friend_type);
295 classes = CLASSTYPE_FRIEND_CLASSES (type);
297 /* Stop if we find the same type on the list. */
298 && !(TREE_CODE (TREE_VALUE (classes)) == TEMPLATE_DECL ?
299 friend_type == TREE_VALUE (classes) :
300 same_type_p (TREE_VALUE (classes), friend_type)))
301 classes = TREE_CHAIN (classes);
303 cp_warning ("`%T' is already a friend of `%T'",
304 TREE_VALUE (classes), type);
307 CLASSTYPE_FRIEND_CLASSES (type)
308 = tree_cons (NULL_TREE, friend_type, CLASSTYPE_FRIEND_CLASSES (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));
374 /* A nested class may declare a member of an enclosing class
375 to be a friend, so we do lookup here even if CTYPE is in
376 the process of being defined. */
377 if (TYPE_SIZE (ctype) != 0 || TYPE_BEING_DEFINED (ctype))
379 /* But, we defer looup in template specializations until
380 they are fully specialized. */
381 if (template_class_depth (ctype) == 0)
382 decl = check_classfn (ctype, decl);
385 add_friend (current_class_type, decl);
388 cp_error ("member `%D' declared as friend before type `%T' defined",
393 /* Possibly a bunch of method friends. */
395 /* Get the class they belong to. */
396 tree ctype = IDENTIFIER_TYPE_VALUE (cname);
397 tree fields = lookup_fnfields (TYPE_BINFO (ctype), declarator, 0);
400 add_friends (current_class_type, declarator, ctype);
402 cp_error ("method `%D' is not a member of class `%T'",
404 decl = void_type_node;
408 @@ or possibly a friend from a base class ?!? */
409 else if (TREE_CODE (decl) == FUNCTION_DECL)
411 /* Friends must all go through the overload machinery,
412 even though they may not technically be overloaded.
414 Note that because classes all wind up being top-level
415 in their scope, their friend wind up in top-level scope as well. */
416 DECL_ARGUMENTS (decl) = parmdecls;
418 DECL_CLASS_CONTEXT (decl) = current_class_type;
420 if (! DECL_USE_TEMPLATE (decl))
422 /* We can call pushdecl here, because the TREE_CHAIN of this
423 FUNCTION_DECL is not needed for other purposes. Don't do
424 this for a template instantiation. However, we don't
425 call pushdecl() for a friend function of a template
426 class, since in general, such a declaration depends on
427 template parameters. Instead, we call pushdecl when the
428 class is instantiated. */
429 if (!is_friend_template
430 && template_class_depth (current_class_type) == 0)
431 decl = pushdecl (decl);
433 decl = push_template_decl_real (decl, /*is_friend=*/1);
435 if (warn_nontemplate_friend
436 && ! funcdef_flag && ! flag_guiding_decls && ! is_friend_template
437 && current_template_parms && uses_template_parms (decl))
439 static int explained;
440 cp_warning ("friend declaration `%#D'", decl);
441 warning (" declares a non-template function");
444 warning (" (if this is not what you intended, make sure");
445 warning (" the function template has already been declared,");
446 warning (" and add <> after the function name here)");
447 warning (" -Wno-non-template-friend disables this warning.");
453 make_decl_rtl (decl, NULL_PTR, 1);
454 add_friend (current_class_type,
455 is_friend_template ? DECL_TI_TEMPLATE (decl) : decl);
456 DECL_FRIEND_P (decl) = 1;
460 /* @@ Should be able to ingest later definitions of this function
462 tree decl = lookup_name_nonclass (declarator);
463 if (decl == NULL_TREE)
465 cp_warning ("implicitly declaring `%T' as struct", declarator);
466 decl = xref_tag (record_type_node, declarator, 1);
467 decl = TYPE_MAIN_DECL (decl);
470 /* Allow abbreviated declarations of overloaded functions,
471 but not if those functions are really class names. */
472 if (TREE_CODE (decl) == TREE_LIST && TREE_TYPE (TREE_PURPOSE (decl)))
474 cp_warning ("`friend %T' archaic, use `friend class %T' instead",
475 declarator, declarator);
476 decl = TREE_TYPE (TREE_PURPOSE (decl));
479 if (TREE_CODE (decl) == TREE_LIST)
480 add_friends (current_class_type, TREE_PURPOSE (decl), NULL_TREE);
482 make_friend_class (current_class_type, TREE_TYPE (decl));
483 decl = void_type_node;