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1 /* Handle parameterized types (templates) for GNU C++.
2 Copyright (C) 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000,
3 2001, 2002, 2003, 2004, 2005, 2007, 2008, 2009
4 Free Software Foundation, Inc.
5 Written by Ken Raeburn (raeburn@cygnus.com) while at Watchmaker Computing.
6 Rewritten by Jason Merrill (jason@cygnus.com).
8 This file is part of GCC.
10 GCC is free software; you can redistribute it and/or modify
11 it under the terms of the GNU General Public License as published by
12 the Free Software Foundation; either version 3, or (at your option)
13 any later version.
15 GCC is distributed in the hope that it will be useful,
16 but WITHOUT ANY WARRANTY; without even the implied warranty of
17 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18 GNU General Public License for more details.
20 You should have received a copy of the GNU General Public License
21 along with GCC; see the file COPYING3. If not see
22 <http://www.gnu.org/licenses/>. */
24 /* Known bugs or deficiencies include:
26 all methods must be provided in header files; can't use a source
27 file that contains only the method templates and "just win". */
50 /* The type of functions taking a tree, and some additional data, and
51 returning an int. */
54 /* The PENDING_TEMPLATES is a TREE_LIST of templates whose
55 instantiations have been deferred, either because their definitions
56 were not yet available, or because we were putting off doing the work. */
60 };
75 /* Live only within one (recursive) call to tsubst_expr. We use
76 this to pass the statement expression node from the STMT_EXPR
77 to the EXPR_STMT that is its result. */
80 /* A map from local variable declarations in the body of the template
81 presently being instantiated to the corresponding instantiated
82 local variables. */
85 /* Contains canonical template parameter types. The vector is indexed by
86 the TEMPLATE_TYPE_IDX of the template parameter. Each element is a
87 TREE_LIST, whose TREE_VALUEs contain the canonical template
88 parameters of various types and levels. */
91 #define UNIFY_ALLOW_NONE 0
92 #define UNIFY_ALLOW_MORE_CV_QUAL 1
93 #define UNIFY_ALLOW_LESS_CV_QUAL 2
94 #define UNIFY_ALLOW_DERIVED 4
95 #define UNIFY_ALLOW_INTEGER 8
96 #define UNIFY_ALLOW_OUTER_LEVEL 16
97 #define UNIFY_ALLOW_OUTER_MORE_CV_QUAL 32
98 #define UNIFY_ALLOW_OUTER_LESS_CV_QUAL 64
120 tree);
178 /* Make the current scope suitable for access checking when we are
179 processing T. T can be FUNCTION_DECL for instantiated function
180 template, or VAR_DECL for static member variable (need by
181 instantiate_decl). */
183 static void
185 {
193 else
197 {
198 saved_access_scope = tree_cons
201 }
202 }
204 /* Restore the scope set up by push_access_scope. T is the node we
205 are processing. */
207 static void
209 {
211 {
214 }
218 else
220 }
222 /* Do any processing required when DECL (a member template
223 declaration) is finished. Returns the TEMPLATE_DECL corresponding
224 to DECL, unless it is a specialization, in which case the DECL
225 itself is returned. */
227 tree
229 {
236 {
237 tree type;
245 {
249 }
251 }
255 {
257 {
260 }
261 else
263 }
264 else
268 }
270 /* Return the template info node corresponding to T, whatever T is. */
272 tree
274 {
287 }
289 /* Returns the template nesting level of the indicated class TYPE.
291 For example, in:
292 template <class T>
293 struct A
294 {
295 template <class U>
296 struct B {};
297 };
299 A<T>::B<U> has depth two, while A<T> has depth one.
300 Both A<T>::B<int> and A<int>::B<U> have depth one, if
301 they are instantiations, not specializations.
303 This function is guaranteed to return 0 if passed NULL_TREE so
304 that, for example, `template_class_depth (current_class_type)' is
305 always safe. */
307 int
309 {
316 {
322 }
325 }
327 /* Subroutine of maybe_begin_member_template_processing.
328 Returns true if processing DECL needs us to push template parms. */
330 static bool
332 {
338 }
340 /* Subroutine of maybe_begin_member_template_processing.
341 Push the template parms in PARMS, starting from LEVELS steps into the
342 chain, and ending at the beginning, since template parms are listed
343 innermost first. */
345 static void
347 {
355 current_template_parms
361 NULL);
363 {
372 {
379 {
380 /* Make a CONST_DECL as is done in process_template_parm.
381 It is ugly that we recreate this here; the original
382 version built in process_template_parm is no longer
383 available. */
392 }
397 }
398 }
399 }
401 /* Restore the template parameter context for a member template or
402 a friend template defined in a class definition. */
404 void
406 {
407 tree parms;
411 {
416 {
419 }
422 }
424 /* Remember how many levels of template parameters we pushed so that
425 we can pop them later. */
427 }
429 /* Undo the effects of maybe_begin_member_template_processing. */
431 void
433 {
442 {
446 }
447 }
449 /* Return a new template argument vector which contains all of ARGS,
450 but has as its innermost set of arguments the EXTRA_ARGS. */
452 static tree
454 {
455 tree new_args;
470 }
472 /* Like add_to_template_args, but only the outermost ARGS are added to
473 the EXTRA_ARGS. In particular, all but TMPL_ARGS_DEPTH
474 (EXTRA_ARGS) levels are added. This function is used to combine
475 the template arguments from a partial instantiation with the
476 template arguments used to attain the full instantiation from the
477 partial instantiation. */
479 static tree
481 {
482 tree new_args;
484 /* If there are more levels of EXTRA_ARGS than there are ARGS,
485 something very fishy is going on. */
488 /* If *all* the new arguments will be the EXTRA_ARGS, just return
489 them. */
493 /* For the moment, we make ARGS look like it contains fewer levels. */
498 /* Now, we restore ARGS to its full dimensions. */
502 }
504 /* Return the N levels of innermost template arguments from the ARGS. */
506 tree
508 {
509 tree new_args;
515 /* If N is 1, just return the innermost set of template arguments. */
519 /* If we're not removing anything, just return the arguments we were
520 given. */
526 /* Make a new set of arguments, not containing the outer arguments. */
533 }
535 /* The inverse of get_innermost_template_args: Return all but the innermost
536 EXTRA_LEVELS levels of template arguments from the ARGS. */
538 static tree
540 {
541 tree new_args;
547 /* If N is 1, just return the outermost set of template arguments. */
551 /* If we're not removing anything, just return the arguments we were
552 given. */
557 /* Make a new set of arguments, not containing the inner arguments. */
564 }
566 /* We've got a template header coming up; push to a new level for storing
567 the parms. */
569 void
571 {
572 /* We use a non-tag-transparent scope here, which causes pushtag to
573 put tags in this scope, rather than in the enclosing class or
574 namespace scope. This is the right thing, since we want
575 TEMPLATE_DECLS, and not TYPE_DECLS for template classes. For a
576 global template class, push_template_decl handles putting the
577 TEMPLATE_DECL into top-level scope. For a nested template class,
578 e.g.:
580 template <class T> struct S1 {
581 template <class T> struct S2 {};
582 };
584 pushtag contains special code to call pushdecl_with_scope on the
585 TEMPLATE_DECL for S2. */
590 }
592 /* This routine is called when a specialization is declared. If it is
593 invalid to declare a specialization here, an error is reported and
594 false is returned, otherwise this routine will return true. */
596 static bool
598 {
601 /* [temp.expl.spec]
603 An explicit specialization shall be declared in the namespace of
604 which the template is a member, or, for member templates, in the
605 namespace of which the enclosing class or enclosing class
606 template is a member. An explicit specialization of a member
607 function, member class or static data member of a class template
608 shall be declared in the namespace of which the class template
609 is a member. */
611 {
614 }
616 /* [temp.expl.spec]
618 In an explicit specialization declaration for a member of a class
619 template or a member template that appears in namespace scope,
620 the member template and some of its enclosing class templates may
621 remain unspecialized, except that the declaration shall not
622 explicitly specialize a class member template if its enclosing
623 class templates are not explicitly specialized as well. */
625 {
628 }
631 }
633 /* We've just seen template <>. */
635 bool
637 {
641 }
643 /* Called at then end of processing a declaration preceded by
644 template<>. */
646 void
648 {
651 }
653 /* Any template <>'s that we have seen thus far are not referring to a
654 function specialization. */
656 void
658 {
661 }
663 /* We've just seen a template header. If SPECIALIZATION is nonzero,
664 it was of the form template <>. */
666 static void
668 {
670 template_header_count++;
671 }
673 /* We're beginning an explicit instantiation. */
675 void
677 {
680 }
683 void
685 {
688 }
690 /* An explicit specialization or partial specialization TMPL is being
691 declared. Check that the namespace in which the specialization is
692 occurring is permissible. Returns false iff it is invalid to
693 specialize TMPL in the current namespace. */
695 static bool
697 {
700 /* [tmpl.expl.spec]
702 An explicit specialization shall be declared in the namespace of
703 which the template is a member, or, for member templates, in the
704 namespace of which the enclosing class or enclosing class
705 template is a member. An explicit specialization of a member
706 function, member class or static data member of a class template
707 shall be declared in the namespace of which the class template is
708 a member. */
710 /* Same or super-using namespace. */
712 else
713 {
717 }
718 }
720 /* SPEC is an explicit instantiation. Check that it is valid to
721 perform this explicit instantiation in the current namespace. */
723 static void
725 {
726 tree ns;
728 /* DR 275: An explicit instantiation shall appear in an enclosing
729 namespace of its template. */
735 }
737 /* The TYPE is being declared. If it is a template type, that means it
738 is a partial specialization. Do appropriate error-checking. */
740 tree
742 {
743 tree context;
749 {
753 }
758 {
759 /* This is for ordinary explicit specialization and partial
760 specialization of a template class such as:
762 template <> class C<int>;
764 or:
766 template <class T> class C<T*>;
768 Make sure that `C<int>' and `C<T*>' are implicit instantiations. */
772 {
776 {
780 }
781 }
784 }
790 {
791 /* This is for an explicit specialization of member class
792 template according to [temp.expl.spec/18]:
794 template <> template <class U> class C<int>::D;
796 The context `C<int>' must be an implicit instantiation.
797 Otherwise this is just a member class template declared
798 earlier like:
800 template <> class C<int> { template <class U> class D; };
801 template <> template <class U> class C<int>::D;
803 In the first case, `C<int>::D' is a specialization of `C<T>::D'
804 while in the second case, `C<int>::D' is a primary template
805 and `C<T>::D' may not exist. */
809 {
810 tree t;
814 {
818 }
820 /* Check for invalid specialization after instantiation:
822 template <> template <> class C<int>::D<int>;
823 template <> template <class U> class C<int>::D; */
833 /* Mark TYPE as a specialization. And as a result, we only
834 have one level of template argument for the innermost
835 class template. */
839 }
840 }
842 {
845 }
848 }
850 /* Returns nonzero if we can optimize the retrieval of specializations
851 for TMPL, a TEMPLATE_DECL. In particular, for such a template, we
852 do not use DECL_TEMPLATE_SPECIALIZATIONS at all. */
856 {
859 /* DECL_CLASS_SCOPE_P holds of T::f even if T is a template
860 parameter. */
862 /* The optimized lookup depends on the fact that the
863 template arguments for the member function template apply
864 purely to the containing class, which is not true if the
865 containing class is an explicit or partial
866 specialization. */
870 /* It is possible to have a template that is not a member
871 template and is not a member of a template class:
873 template <typename T>
874 struct S { friend A::f(); };
876 Here, the friend function is a template, but the context does
877 not have template information. The optimized lookup relies
878 on having ARGS be the template arguments for both the class
879 and the function template. */
881 }
883 /* Retrieve the specialization (in the sense of [temp.spec] - a
884 specialization is either an instantiation or an explicit
885 specialization) of TMPL for the given template ARGS. If there is
886 no such specialization, return NULL_TREE. The ARGS are a vector of
887 arguments, or a vector of vectors of arguments, in the case of
888 templates with more than one level of parameters.
890 If TMPL is a type template and CLASS_SPECIALIZATIONS_P is true,
891 then we search for a partial specialization matching ARGS. This
892 parameter is ignored if TMPL is not a class template. */
894 static tree
897 {
903 /* There should be as many levels of arguments as there are
904 levels of parameters. */
909 {
910 tree class_template;
911 tree class_specialization;
913 tree fns;
916 /* The template arguments actually apply to the containing
917 class. Find the class specialization with those
918 arguments. */
920 class_specialization
925 /* Now, find the appropriate entry in the CLASSTYPE_METHOD_VEC
926 for the specialization. */
930 /* Iterate through the methods with the indicated name, looking
931 for the one that has an instance of TMPL. */
934 {
938 }
940 }
941 else
942 {
946 /* Class templates store their instantiations on the
947 DECL_TEMPLATE_INSTANTIATIONS list; other templates use the
948 DECL_TEMPLATE_SPECIALIZATIONS list. */
953 else
956 /* Iterate through the list until we find a matching template. */
958 {
962 {
963 /* Use the move-to-front heuristic to speed up future
964 searches. */
966 {
970 }
972 }
974 }
975 }
978 }
980 /* Like retrieve_specialization, but for local declarations. */
982 static tree
984 {
985 tree spec;
993 }
995 /* Returns nonzero iff DECL is a specialization of TMPL. */
997 int
999 {
1000 tree t;
1003 {
1009 }
1010 else
1011 {
1020 }
1023 }
1025 /* Returns nonzero iff DECL is a specialization of friend declaration
1026 FRIEND_DECL according to [temp.friend]. */
1028 bool
1030 {
1037 /* For [temp.friend/6] when FRIEND_DECL is an ordinary member function
1038 of a template class, we want to check if DECL is a specialization
1039 if this. */
1043 {
1044 /* We want a TEMPLATE_DECL for `is_specialization_of'. */
1047 }
1052 /* There is nothing to do if this is not a template friend. */
1059 /* [temp.friend/6]
1060 A member of a class template may be declared to be a friend of a
1061 non-template class. In this case, the corresponding member of
1062 every specialization of the class template is a friend of the
1063 class granting friendship.
1065 For example, given a template friend declaration
1067 template <class T> friend void A<T>::f();
1069 the member function below is considered a friend
1071 template <> struct A<int> {
1072 void f();
1073 };
1075 For this type of template friend, TEMPLATE_DEPTH below will be
1076 nonzero. To determine if DECL is a friend of FRIEND, we first
1077 check if the enclosing class is a specialization of another. */
1084 {
1085 /* Next, we check the members themselves. In order to handle
1086 a few tricky cases, such as when FRIEND_DECL's are
1088 template <class T> friend void A<T>::g(T t);
1089 template <class T> template <T t> friend void A<T>::h();
1091 and DECL's are
1093 void A<int>::g(int);
1094 template <int> void A<int>::h();
1096 we need to figure out ARGS, the template arguments from
1097 the context of DECL. This is required for template substitution
1098 of `T' in the function parameter of `g' and template parameter
1099 of `h' in the above examples. Here ARGS corresponds to `int'. */
1106 {
1108 {
1111 else
1113 current_depth++;
1114 }
1116 }
1119 {
1121 tree friend_type;
1122 tree decl_type;
1123 tree friend_args_type;
1124 tree decl_args_type;
1126 /* Make sure that both DECL and FRIEND_DECL are templates or
1127 non-templates. */
1133 {
1134 /* If both are templates, check template parameter list. */
1135 tree friend_parms
1140 friend_parms))
1144 }
1145 else
1153 /* Check if return types match. */
1157 /* Check if function parameter types match, ignoring the
1158 `this' parameter. */
1167 }
1168 else
1169 {
1170 /* DECL is a TYPE_DECL */
1174 /* Make sure that both DECL and FRIEND_DECL are templates or
1175 non-templates. */
1176 is_template
1183 {
1184 tree friend_parms;
1185 /* If both are templates, check the name of the two
1186 TEMPLATE_DECL's first because is_friend didn't. */
1191 /* Now check template parameter list. */
1192 friend_parms
1195 return comp_template_parms
1197 friend_parms);
1198 }
1199 else
1202 }
1203 }
1205 }
1207 /* Register the specialization SPEC as a specialization of TMPL with
1208 the indicated ARGS. IS_FRIEND indicates whether the specialization
1209 is actually just a friend declaration. Returns SPEC, or an
1210 equivalent prior declaration, if available. */
1212 static tree
1214 {
1215 tree fn;
1221 /* This is the FUNCTION_DECL for a partial instantiation. Don't
1222 register it; we want the corresponding TEMPLATE_DECL instead.
1223 We use `uses_template_parms (DECL_TI_ARGS (spec))' rather than
1224 the more obvious `uses_template_parms (spec)' to avoid problems
1225 with default function arguments. In particular, given
1226 something like this:
1228 template <class T> void f(T t1, T t = T())
1230 the default argument expression is not substituted for in an
1231 instantiation unless and until it is actually needed. */
1236 /* We can sometimes try to re-register a specialization that we've
1237 already got. In particular, regenerate_decl_from_template calls
1238 duplicate_decls which will update the specialization list. But,
1239 we'll still get called again here anyhow. It's more convenient
1240 to simply allow this than to try to prevent it. */
1244 {
1246 {
1249 {
1251 fn);
1253 }
1254 else
1255 {
1256 tree clone;
1257 /* This situation should occur only if the first
1258 specialization is an implicit instantiation, the
1259 second is an explicit specialization, and the
1260 implicit instantiation has not yet been used. That
1261 situation can occur if we have implicitly
1262 instantiated a member function and then specialized
1263 it later.
1265 We can also wind up here if a friend declaration that
1266 looked like an instantiation turns out to be a
1267 specialization:
1269 template <class T> void foo(T);
1270 class S { friend void foo<>(int) };
1271 template <> void foo(int);
1273 We transform the existing DECL in place so that any
1274 pointers to it become pointers to the updated
1275 declaration.
1277 If there was a definition for the template, but not
1278 for the specialization, we want this to look as if
1279 there were no definition, and vice versa. */
1282 /* The call to duplicate_decls will have applied
1283 [temp.expl.spec]:
1285 An explicit specialization of a function template
1286 is inline only if it is explicitly declared to be,
1287 and independently of whether its function template
1288 is.
1290 to the primary function; now copy the inline bits to
1291 the various clones. */
1298 }
1299 }
1301 {
1303 /* Dup decl failed, but this is a new definition. Set the
1304 line number so any errors match this new
1305 definition. */
1309 }
1310 }
1312 /* A specialization must be declared in the same namespace as the
1313 template it is specializing. */
1323 }
1325 /* Unregister the specialization SPEC as a specialization of TMPL.
1326 Replace it with NEW_SPEC, if NEW_SPEC is non-NULL. Returns true
1327 if the SPEC was listed as a specialization of TMPL. */
1329 bool
1331 {
1338 {
1341 else
1344 }
1347 }
1349 /* Compare an entry in the local specializations hash table P1 (which
1350 is really a pointer to a TREE_LIST) with P2 (which is really a
1351 DECL). */
1353 static int
1355 {
1357 }
1359 /* Hash P1, an entry in the local specializations table. */
1361 static hashval_t
1363 {
1365 }
1367 /* Like register_specialization, but for local declarations. We are
1368 registering SPEC, an instantiation of TMPL. */
1370 static void
1372 {
1378 }
1380 /* TYPE is a class type. Returns true if TYPE is an explicitly
1381 specialized class. */
1383 bool
1385 {
1389 }
1391 /* Print the list of candidate FNS in an error message. */
1393 void
1395 {
1396 tree fn;
1401 {
1402 tree f;
1407 }
1408 }
1410 /* Returns the template (one of the functions given by TEMPLATE_ID)
1411 which can be specialized to match the indicated DECL with the
1412 explicit template args given in TEMPLATE_ID. The DECL may be
1413 NULL_TREE if none is available. In that case, the functions in
1414 TEMPLATE_ID are non-members.
1416 If NEED_MEMBER_TEMPLATE is nonzero the function is known to be a
1417 specialization of a member template.
1419 The TEMPLATE_COUNT is the number of references to qualifying
1420 template classes that appeared in the name of the function. See
1421 check_explicit_specialization for a more accurate description.
1423 TSK indicates what kind of template declaration (if any) is being
1424 declared. TSK_TEMPLATE indicates that the declaration given by
1425 DECL, though a FUNCTION_DECL, has template parameters, and is
1426 therefore a template function.
1428 The template args (those explicitly specified and those deduced)
1429 are output in a newly created vector *TARGS_OUT.
1431 If it is impossible to determine the result, an error message is
1432 issued. The error_mark_node is returned to indicate failure. */
1434 static tree
1436 tree decl,
1440 tmpl_spec_kind tsk)
1441 {
1442 tree fns;
1443 tree targs;
1444 tree explicit_targs;
1446 /* A TREE_LIST of templates of which DECL may be a specialization.
1447 The TREE_VALUE of each node is a TEMPLATE_DECL. The
1448 corresponding TREE_PURPOSE is the set of template arguments that,
1449 when used to instantiate the template, would produce a function
1450 with the signature of DECL. */
1466 /* Check for baselinks. */
1471 {
1474 }
1476 /* Count the number of template headers specified for this
1477 specialization. */
1485 {
1489 {
1490 tree decl_arg_types;
1491 tree fn_arg_types;
1493 /* In case of explicit specialization, we need to check if
1494 the number of template headers appearing in the specialization
1495 is correct. This is usually done in check_explicit_specialization,
1496 but the check done there cannot be exhaustive when specializing
1497 member functions. Consider the following code:
1499 template <> void A<int>::f(int);
1500 template <> template <> void A<int>::f(int);
1502 Assuming that A<int> is not itself an explicit specialization
1503 already, the first line specializes "f" which is a non-template
1504 member function, whilst the second line specializes "f" which
1505 is a template member function. So both lines are syntactically
1506 correct, and check_explicit_specialization does not reject
1507 them.
1509 Here, we can do better, as we are matching the specialization
1510 against the declarations. We count the number of template
1511 headers, and we check if they match TEMPLATE_COUNT + 1
1512 (TEMPLATE_COUNT is the number of qualifying template classes,
1513 plus there must be another header for the member template
1514 itself).
1516 Notice that if header_count is zero, this is not a
1517 specialization but rather a template instantiation, so there
1518 is no check we can perform here. */
1522 /* Check that the number of template arguments at the
1523 innermost level for DECL is the same as for FN. */
1531 /* DECL might be a specialization of FN. */
1535 /* For a non-static member function, we need to make sure
1536 that the const qualification is the same. Since
1537 get_bindings does not try to merge the "this" parameter,
1538 we must do the comparison explicitly. */
1544 /* Skip the "this" parameter and, for constructors of
1545 classes with virtual bases, the VTT parameter. A
1546 full specialization of a constructor will have a VTT
1547 parameter, but a template never will. */
1548 decl_arg_types
1550 fn_arg_types
1553 /* Check that the number of function parameters matches.
1554 For example,
1555 template <class T> void f(int i = 0);
1556 template <> void f<int>();
1557 The specialization f<int> is invalid but is not caught
1558 by get_bindings below. */
1562 /* Function templates cannot be specializations; there are
1563 no partial specializations of functions. Therefore, if
1564 the type of DECL does not match FN, there is no
1565 match. */
1567 {
1571 }
1573 /* See whether this function might be a specialization of this
1574 template. */
1578 /* We cannot deduce template arguments that when used to
1579 specialize TMPL will produce DECL. */
1582 /* Save this template, and the arguments deduced. */
1584 }
1586 /* FN is an ordinary member function, and we need a
1587 specialization of a member template. */
1588 ;
1590 /* We can get IDENTIFIER_NODEs here in certain erroneous
1591 cases. */
1592 ;
1594 /* This is just an ordinary non-member function. Nothing can
1595 be a specialization of that. */
1596 ;
1598 /* Cannot specialize functions that are created implicitly. */
1599 ;
1600 else
1601 {
1602 tree decl_arg_types;
1604 /* This is an ordinary member function. However, since
1605 we're here, we can assume it's enclosing class is a
1606 template class. For example,
1608 template <typename T> struct S { void f(); };
1609 template <> void S<int>::f() {}
1611 Here, S<int>::f is a non-template, but S<int> is a
1612 template class. If FN has the same type as DECL, we
1613 might be in business. */
1616 /* Its enclosing class is an explicit specialization
1617 of a template class. This is not a candidate. */
1622 /* The return types differ. */
1625 /* Adjust the type of DECL in case FN is a static member. */
1632 decl_arg_types))
1633 /* They match! */
1635 }
1636 }
1639 {
1640 /* We have:
1642 [temp.expl.spec]
1644 It is possible for a specialization with a given function
1645 signature to be instantiated from more than one function
1646 template. In such cases, explicit specification of the
1647 template arguments must be used to uniquely identify the
1648 function template specialization being specialized.
1650 Note that here, there's no suggestion that we're supposed to
1651 determine which of the candidate templates is most
1652 specialized. However, we, also have:
1654 [temp.func.order]
1656 Partial ordering of overloaded function template
1657 declarations is used in the following contexts to select
1658 the function template to which a function template
1659 specialization refers:
1661 -- when an explicit specialization refers to a function
1662 template.
1664 So, we do use the partial ordering rules, at least for now.
1665 This extension can only serve to make invalid programs valid,
1666 so it's safe. And, there is strong anecdotal evidence that
1667 the committee intended the partial ordering rules to apply;
1668 the EDG front end has that behavior, and John Spicer claims
1669 that the committee simply forgot to delete the wording in
1670 [temp.expl.spec]. */
1673 {
1676 }
1677 }
1680 {
1684 }
1688 {
1694 }
1696 /* We have one, and exactly one, match. */
1698 {
1700 /* DECL is a re-declaration of a template function. */
1703 /* It was a specialization of an ordinary member function in a
1704 template class. */
1707 }
1709 /* It was a specialization of a template. */
1712 {
1717 }
1718 else
1721 }
1723 /* Returns a chain of parameter types, exactly like the SPEC_TYPES,
1724 but with the default argument values filled in from those in the
1725 TMPL_TYPES. */
1727 static tree
1729 tree tmpl_types)
1730 {
1731 tree new_spec_types;
1739 /* Substitute into the rest of the list. */
1740 new_spec_types =
1744 /* Add the default argument for this parameter. */
1747 new_spec_types);
1748 }
1750 /* DECL is an explicit specialization. Replicate default arguments
1751 from the template it specializes. (That way, code like:
1753 template <class T> void f(T = 3);
1754 template <> void f(double);
1755 void g () { f (); }
1757 works, as required.) An alternative approach would be to look up
1758 the correct default arguments at the call-site, but this approach
1759 is consistent with how implicit instantiations are handled. */
1761 static void
1763 {
1764 tree tmpl;
1765 tree spec_types;
1766 tree tmpl_types;
1767 tree new_spec_types;
1768 tree old_type;
1769 tree new_type;
1770 tree t;
1775 /* See if there's anything we need to do. */
1788 {
1789 /* Remove the this pointer, but remember the object's type for
1790 CV quals. */
1796 {
1797 /* DECL may contain more parameters than TMPL due to the extra
1798 in-charge parameter in constructors and destructors. */
1801 }
1803 {
1806 }
1807 }
1809 /* Compute the merged default arguments. */
1810 new_spec_types =
1813 /* Compute the new FUNCTION_TYPE. */
1815 {
1819 new_spec_types);
1822 /* Put the in-charge parameter back. */
1825 new_spec_types);
1829 new_spec_types);
1830 }
1831 else
1833 new_spec_types);
1839 }
1841 /* Check to see if the function just declared, as indicated in
1842 DECLARATOR, and in DECL, is a specialization of a function
1843 template. We may also discover that the declaration is an explicit
1844 instantiation at this point.
1846 Returns DECL, or an equivalent declaration that should be used
1847 instead if all goes well. Issues an error message if something is
1848 amiss. Returns error_mark_node if the error is not easily
1849 recoverable.
1851 FLAGS is a bitmask consisting of the following flags:
1853 2: The function has a definition.
1854 4: The function is a friend.
1856 The TEMPLATE_COUNT is the number of references to qualifying
1857 template classes that appeared in the name of the function. For
1858 example, in
1860 template <class T> struct S { void f(); };
1861 void S<int>::f();
1863 the TEMPLATE_COUNT would be 1. However, explicitly specialized
1864 classes are not counted in the TEMPLATE_COUNT, so that in
1866 template <class T> struct S {};
1867 template <> struct S<int> { void f(); }
1868 template <> void S<int>::f();
1870 the TEMPLATE_COUNT would be 0. (Note that this declaration is
1871 invalid; there should be no template <>.)
1873 If the function is a specialization, it is marked as such via
1874 DECL_TEMPLATE_SPECIALIZATION. Furthermore, its DECL_TEMPLATE_INFO
1875 is set up correctly, and it is added to the list of specializations
1876 for that template. */
1878 tree
1880 tree decl,
1883 {
1891 tmpl_spec_kind tsk;
1894 {
1897 else
1899 }
1900 else
1904 {
1907 {
1910 }
1912 {
1914 /* This could be something like:
1916 template <class T> void f(T);
1917 class S { friend void f<>(int); } */
1919 else
1920 {
1921 /* This case handles bogus declarations like template <>
1922 template <class T> void f<int>(); */
1925 declarator);
1927 }
1928 }
1932 /* The error has already been reported in
1933 check_specialization_scope. */
1939 /* Fall through. */
1952 decl);
1955 else
1959 /* Fall through. */
1964 else
1970 {
1971 /* This case handles bogus declarations like template <>
1972 template <class T> void f<int>(); */
1977 else
1979 declarator);
1981 }
1984 /* This is a specialization of a member template, without
1985 specialization the containing class. Something like:
1987 template <class T> struct S {
1988 template <class U> void f (U);
1989 };
1990 template <> template <class U> void S<int>::f(U) {}
1992 That's a specialization -- but of the entire template. */
1998 }
2001 {
2005 {
2009 }
2010 }
2013 {
2017 /* Make sure that the declarator is a TEMPLATE_ID_EXPR. */
2019 {
2020 tree fns;
2025 else
2026 {
2027 /* If there is no class context, the explicit instantiation
2028 must be at namespace scope. */
2031 /* Find the namespace binding, using the declaration
2032 context. */
2036 {
2039 }
2040 else
2041 {
2047 }
2048 }
2051 }
2057 {
2059 /* A specialization in class scope. This is invalid,
2060 but the error will already have been flagged by
2061 check_specialization_scope. */
2063 else
2064 {
2065 /* It's not valid to write an explicit instantiation in
2066 class scope, e.g.:
2068 class C { template void f(); }
2070 This case is caught by the parser. However, on
2071 something like:
2073 template class C { void f(); };
2075 (which is invalid) we can get here. The error will be
2076 issued later. */
2077 ;
2078 }
2081 }
2084 IDENTIFIER_NODE))
2085 {
2086 /* Find the list of functions in ctype that have the same
2087 name as the declared function. */
2093 {
2098 {
2099 /* From [temp.expl.spec]:
2101 If such an explicit specialization for the member
2102 of a class template names an implicitly-declared
2103 special member function (clause _special_), the
2104 program is ill-formed.
2106 Similar language is found in [temp.explicit]. */
2109 }
2112 }
2115 {
2119 }
2120 else
2121 {
2123 tree ovl;
2125 /* For a type-conversion operator, we cannot do a
2126 name-based lookup. We might be looking for `operator
2127 int' which will be a specialization of `operator T'.
2128 So, we find *all* the conversion operators, and then
2129 select from them. */
2137 {
2139 /* There are no more conversion functions. */
2142 /* Glue all these conversion functions together
2143 with those we already have. */
2146 }
2147 }
2150 {
2153 }
2154 else
2156 }
2158 /* Figure out what exactly is being specialized at this point.
2159 Note that for an explicit instantiation, even one for a
2160 member function, we cannot tell apriori whether the
2161 instantiation is for a member template, or just a member
2162 function of a template class. Even if a member template is
2163 being instantiated, the member template arguments may be
2164 elided if they can be deduced from the rest of the
2165 declaration. */
2168 member_specialization,
2169 template_count,
2170 tsk);
2173 /* We couldn't figure out what this declaration was
2174 specializing. */
2176 else
2177 {
2181 {
2182 /* We don't set DECL_EXPLICIT_INSTANTIATION here; that
2183 is done by do_decl_instantiation later. */
2189 {
2190 /* If TMPL is not the most general template (for
2191 example, if TMPL is a friend template that is
2192 injected into namespace scope), then there will
2193 be too many levels of TARGS. Remove some of them
2194 here. */
2196 tree new_targs;
2203 }
2206 }
2208 /* If we thought that the DECL was a member function, but it
2209 turns out to be specializing a static member function,
2210 make DECL a static member function as well. */
2215 /* If this is a specialization of a member template of a
2216 template class, we want to return the TEMPLATE_DECL, not
2217 the specialization of it. */
2219 {
2223 {
2227 /* We want to use the argument list specified in the
2228 definition, not in the original declaration. */
2231 }
2233 }
2235 /* Set up the DECL_TEMPLATE_INFO for DECL. */
2238 /* Inherit default function arguments from the template
2239 DECL is specializing. */
2242 /* This specialization has the same protection as the
2243 template it specializes. */
2247 /* 7.1.1-1 [dcl.stc]
2249 A storage-class-specifier shall not be specified in an
2250 explicit specialization...
2252 The parser rejects these, so unless action is taken here,
2253 explicit function specializations will always appear with
2254 global linkage.
2256 The action recommended by the C++ CWG in response to C++
2257 defect report 605 is to make the storage class and linkage
2258 of the explicit specialization match the templated function:
2260 http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#605
2261 */
2263 {
2267 /* This specialization has the same linkage and visibility as
2268 the function template it specializes. */
2271 {
2274 }
2277 {
2280 }
2281 }
2283 /* If DECL is a friend declaration, declared using an
2284 unqualified name, the namespace associated with DECL may
2285 have been set incorrectly. For example, in:
2287 template <typename T> void f(T);
2288 namespace N {
2289 struct S { friend void f<int>(int); }
2290 }
2292 we will have set the DECL_CONTEXT for the friend
2293 declaration to N, rather than to the global namespace. */
2298 /* This is not really a declaration of a specialization.
2299 It's just the name of an instantiation. But, it's not
2300 a request for an instantiation, either. */
2303 /* This is indeed a specialization. In case of constructors
2304 and destructors, we need in-charge and not-in-charge
2305 versions in V3 ABI. */
2308 /* Register this specialization so that we can find it
2309 again. */
2311 }
2312 }
2315 }
2317 /* Returns 1 iff PARMS1 and PARMS2 are identical sets of template
2318 parameters. These are represented in the same format used for
2319 DECL_TEMPLATE_PARMS. */
2321 int
2323 {
2324 const_tree p1;
2325 const_tree p2;
2333 {
2345 {
2349 /* If either of the template parameters are invalid, assume
2350 they match for the sake of error recovery. */
2363 }
2364 }
2367 /* One set of parameters has more parameters lists than the
2368 other. */
2372 }
2374 /* Determine whether PARM is a parameter pack. */
2375 bool
2377 {
2378 /* Determine if we have a non-type template parameter pack. */
2383 /* If this is a list of template parameters, we could get a
2384 TYPE_DECL or a TEMPLATE_DECL. */
2391 }
2393 /* Determine whether ARGS describes a variadic template args list,
2394 i.e., one that is terminated by a template argument pack. */
2395 static bool
2397 {
2399 tree last_parm;
2413 }
2415 /* Generate a new name for the parameter pack name NAME (an
2416 IDENTIFIER_NODE) that incorporates its */
2417 static tree
2419 {
2420 /* Munge the name to include the parameter index. */
2428 }
2430 /* Structure used to track the progress of find_parameter_packs_r. */
2431 struct find_parameter_pack_data
2432 {
2433 /* TREE_LIST that will contain all of the parameter packs found by
2434 the traversal. */
2437 /* Set of AST nodes that have been visited by the traversal. */
2439 };
2441 /* Identifies all of the argument packs that occur in a template
2442 argument and appends them to the TREE_LIST inside DATA, which is a
2443 find_parameter_pack_data structure. This is a subroutine of
2444 make_pack_expansion and uses_parameter_packs. */
2445 static tree
2447 {
2453 /* Identify whether this is a parameter pack or not. */
2455 {
2469 {
2470 /* We don't want to walk into the type of a PARM_DECL,
2471 because we don't want to see the type parameter pack. */
2474 }
2478 /* Not a parameter pack. */
2480 }
2483 {
2484 /* Add this parameter pack to the list. */
2486 }
2492 /* This switch statement will return immediately if we don't find a
2493 parameter pack. */
2495 {
2500 /* Check the template itself. */
2503 /* Check the template arguments. */
2519 /* Fall through. */
2560 }
2563 }
2565 /* Determines if the expression or type T uses any parameter packs. */
2566 bool
2568 {
2576 }
2578 /* Turn ARG, which may be an expression, type, or a TREE_LIST
2579 representation a base-class initializer into a parameter pack
2580 expansion. If all goes well, the resulting node will be an
2581 EXPR_PACK_EXPANSION, TYPE_PACK_EXPANSION, or TREE_LIST,
2582 respectively. */
2583 tree
2585 {
2586 tree result;
2595 {
2596 /* The only time we will see a TREE_LIST here is for a base
2597 class initializer. In this case, the TREE_PURPOSE will be a
2598 _TYPE node (representing the base class expansion we're
2599 initializing) and the TREE_VALUE will be a TREE_LIST
2600 containing the initialization arguments.
2602 The resulting expansion looks somewhat different from most
2603 expansions. Rather than returning just one _EXPANSION, we
2604 return a TREE_LIST whose TREE_PURPOSE is a
2605 TYPE_PACK_EXPANSION containing the bases that will be
2606 initialized. The TREE_VALUE will be identical to the
2607 original TREE_VALUE, which is a list of arguments that will
2608 be passed to each base. We do not introduce any new pack
2609 expansion nodes into the TREE_VALUE (although it is possible
2610 that some already exist), because the TREE_PURPOSE and
2611 TREE_VALUE all need to be expanded together with the same
2612 _EXPANSION node. Note that the TYPE_PACK_EXPANSION in the
2613 resulting TREE_PURPOSE will mention the parameter packs in
2614 both the bases and the arguments to the bases. */
2615 tree purpose;
2616 tree value;
2619 /* Determine which parameter packs will be used by the base
2620 class expansion. */
2627 {
2631 }
2634 {
2635 /* Collect the sets of parameter packs used in each of the
2636 initialization arguments. */
2638 {
2639 /* Determine which parameter packs will be expanded in this
2640 argument. */
2643 }
2644 }
2648 /* Create the pack expansion type for the base type. */
2653 /* Just use structural equality for these TYPE_PACK_EXPANSIONS;
2654 they will rarely be compared to anything. */
2658 }
2663 /* Build the PACK_EXPANSION_* node. */
2667 {
2668 /* Propagate type and const-expression information. */
2671 }
2672 else
2673 /* Just use structural equality for these TYPE_PACK_EXPANSIONS;
2674 they will rarely be compared to anything. */
2677 /* Determine which parameter packs will be expanded. */
2683 /* Make sure we found some parameter packs. */
2685 {
2688 else
2691 }
2695 }
2697 /* Checks T for any "bare" parameter packs, which have not yet been
2698 expanded, and issues an error if any are found. This operation can
2699 only be done on full expressions or types (e.g., an expression
2700 statement, "if" condition, etc.), because we could have expressions like:
2702 foo(f(g(h(args)))...)
2704 where "args" is a parameter pack. check_for_bare_parameter_packs
2705 should not be called for the subexpressions args, h(args),
2706 g(h(args)), or f(g(h(args))), because we would produce erroneous
2707 error messages.
2709 Returns TRUE and emits an error if there were bare parameter packs,
2710 returns FALSE otherwise. */
2711 bool
2713 {
2729 {
2732 {
2741 else
2746 else
2750 }
2753 }
2756 }
2758 /* Expand any parameter packs that occur in the template arguments in
2759 ARGS. */
2760 tree
2762 {
2767 /* First, determine if we need to expand anything, and the number of
2768 slots we'll need. */
2770 {
2773 {
2777 else
2779 }
2780 else
2781 {
2783 num_result_args++;
2784 }
2785 }
2787 /* If no expansion is necessary, we're done. */
2791 /* Expand arguments. */
2794 {
2797 {
2802 }
2803 else
2804 {
2807 }
2808 }
2811 }
2813 /* Checks if DECL shadows a template parameter.
2815 [temp.local]: A template-parameter shall not be redeclared within its
2816 scope (including nested scopes).
2818 Emits an error and returns TRUE if the DECL shadows a parameter,
2819 returns FALSE otherwise. */
2821 bool
2823 {
2824 tree olddecl;
2826 /* If we're not in a template, we can't possibly shadow a template
2827 parameter. */
2831 /* Figure out what we're shadowing. */
2836 /* If there's no previous binding for this name, we're not shadowing
2837 anything, let alone a template parameter. */
2841 /* If we're not shadowing a template parameter, we're done. Note
2842 that OLDDECL might be an OVERLOAD (or perhaps even an
2843 ERROR_MARK), so we can't just blithely assume it to be a _DECL
2844 node. */
2848 /* We check for decl != olddecl to avoid bogus errors for using a
2849 name inside a class. We check TPFI to avoid duplicate errors for
2850 inline member templates. */
2858 }
2860 /* Return a new TEMPLATE_PARM_INDEX with the indicated INDEX, LEVEL,
2861 ORIG_LEVEL, DECL, and TYPE. */
2863 static tree
2867 tree decl,
2868 tree type)
2869 {
2880 }
2882 /* Find the canonical type parameter for the given template type
2883 parameter. Returns the canonical type parameter, which may be TYPE
2884 if no such parameter existed. */
2885 static tree
2887 {
2888 tree list;
2902 else
2903 {
2908 }
2909 }
2911 /* Return a TEMPLATE_PARM_INDEX, similar to INDEX, but whose
2912 TEMPLATE_PARM_LEVEL has been decreased by LEVELS. If such a
2913 TEMPLATE_PARM_INDEX already exists, it is returned; otherwise, a
2914 new one is created. */
2916 static tree
2918 tsubst_flags_t complain)
2919 {
2923 {
2941 /* Template template parameters need this. */
2946 }
2949 }
2951 /* Process information from new template parameter PARM and append it to the
2952 LIST being built. This new parameter is a non-type parameter iff
2953 IS_NON_TYPE is true. This new parameter is a parameter
2954 pack iff IS_PARAMETER_PACK is true. */
2956 tree
2959 {
2961 tree defval;
2962 tree err_parm_list;
2969 {
2973 {
2977 else
2979 }
2982 }
2983 else
2987 {
2993 {
2997 }
2998 else
2999 {
3000 /* [temp.param]
3002 The top-level cv-qualifiers on the template-parameter are
3003 ignored when determining its type. */
3006 {
3010 }
3013 {
3014 /* This template parameter is not a parameter pack, but it
3015 should be. Complain about "bare" parameter packs. */
3018 /* Recover by calling this a parameter pack. */
3020 }
3021 }
3023 /* A template parameter is not modifiable. */
3031 processing_template_decl,
3036 }
3037 else
3038 {
3039 tree t;
3043 {
3045 /* This is for distinguishing between real templates and template
3046 template parameters */
3050 }
3051 else
3052 {
3054 /* parm is either IDENTIFIER_NODE or NULL_TREE. */
3056 }
3063 processing_template_decl,
3067 }
3073 }
3075 /* The end of a template parameter list has been reached. Process the
3076 tree list into a parameter vector, converting each parameter into a more
3077 useful form. Type parameters are saved as IDENTIFIER_NODEs, and others
3078 as PARM_DECLs. */
3080 tree
3082 {
3087 current_template_parms
3092 {
3096 }
3101 }
3103 /* end_template_decl is called after a template declaration is seen. */
3105 void
3107 {
3113 /* This matches the pushlevel in begin_template_parm_list. */
3118 }
3120 /* Within the declaration of a template, return all levels of template
3121 parameters that apply. The template parameters are represented as
3122 a TREE_VEC, in the form documented in cp-tree.h for template
3123 arguments. */
3125 static tree
3127 {
3128 tree header;
3133 /* If there is only one level of template parameters, we do not
3134 create a TREE_VEC of TREE_VECs. Instead, we return a single
3135 TREE_VEC containing the arguments. */
3140 {
3146 {
3149 /* T will be a list if we are called from within a
3150 begin/end_template_parm_list pair, but a vector directly
3151 if within a begin/end_member_template_processing pair. */
3153 {
3157 {
3160 {
3164 {
3165 /* Turn this argument into a TYPE_ARGUMENT_PACK
3166 with a single element, which expands T. */
3172 }
3173 }
3174 else
3175 {
3179 {
3180 /* Turn this argument into a NONTYPE_ARGUMENT_PACK
3181 with a single element, which expands T. */
3189 }
3190 }
3192 }
3193 }
3194 }
3198 else
3200 }
3203 }
3205 /* Return a TEMPLATE_DECL corresponding to DECL, using the indicated
3206 template PARMS. If MEMBER_TEMPLATE_P is true, the new template is
3207 a member template. Used by push_template_decl below. */
3209 static tree
3211 {
3217 {
3226 }
3229 }
3231 struct template_parm_data
3232 {
3233 /* The level of the template parameters we are currently
3234 processing. */
3237 /* The index of the specialization argument we are currently
3238 processing. */
3241 /* An array whose size is the number of template parameters. The
3242 elements are nonzero if the parameter has been used in any one
3243 of the arguments processed so far. */
3246 /* An array whose size is the number of template arguments. The
3247 elements are nonzero if the argument makes use of template
3248 parameters of this level. */
3250 };
3252 /* Subroutine of push_template_decl used to see if each template
3253 parameter in a partial specialization is used in the explicit
3254 argument list. If T is of the LEVEL given in DATA (which is
3255 treated as a template_parm_data*), then DATA->PARMS is marked
3256 appropriately. */
3258 static int
3260 {
3266 {
3269 }
3270 else
3271 {
3274 }
3277 {
3280 }
3282 /* Return zero so that for_each_template_parm will continue the
3283 traversal of the tree; we want to mark *every* template parm. */
3285 }
3287 /* Process the partial specialization DECL. */
3289 static tree
3291 {
3297 tree inner_parms;
3310 /* We check that each of the template parameters given in the
3311 partial specialization is used in the argument list to the
3312 specialization. For example:
3314 template <class T> struct S;
3315 template <class T> struct S<T*>;
3317 The second declaration is OK because `T*' uses the template
3318 parameter T, whereas
3320 template <class T> struct S<int>;
3322 is no good. Even trickier is:
3324 template <class T>
3325 struct S1
3326 {
3327 template <class U>
3328 struct S2;
3329 template <class U>
3330 struct S2<T>;
3331 };
3333 The S2<T> declaration is actually invalid; it is a
3334 full-specialization. Of course,
3336 template <class U>
3337 struct S2<T (*)(U)>;
3339 or some such would have been OK. */
3347 {
3352 NULL,
3354 }
3357 {
3358 /* One of the template parms was not used in the
3359 specialization. */
3361 {
3364 }
3367 }
3369 /* [temp.class.spec]
3371 The argument list of the specialization shall not be identical to
3372 the implicit argument list of the primary template. */
3379 /* [temp.class.spec]
3381 A partially specialized non-type argument expression shall not
3382 involve template parameters of the partial specialization except
3383 when the argument expression is a simple identifier.
3385 The type of a template parameter corresponding to a specialized
3386 non-type argument shall not be dependent on a parameter of the
3387 specialization.
3389 Also, we verify that pack expansions only occur at the
3390 end of the argument list. */
3394 {
3401 {
3402 /* Extract the arguments from the argument pack. We'll be
3403 iterating over these in the following loop. */
3406 }
3409 {
3411 /* Get the Jth argument in the parameter pack. */
3415 {
3416 /* Pack expansions must come at the end of the
3417 argument list. */
3420 {
3423 else
3428 }
3429 }
3432 /* We only care about the pattern. */
3438 /* This next line is the `argument expression is not just a
3439 simple identifier' condition and also the `specialized
3440 non-type argument' bit. */
3442 {
3446 arg);
3447 else
3448 {
3449 /* Look at the corresponding template parameter,
3450 marking which template parameters its type depends
3451 upon. */
3455 {
3456 /* We haven't yet initialized TPD2. Do so now. */
3457 tpd2.arg_uses_template_parms
3459 /* The number of parameters here is the number in the
3460 main template, which, as checked in the assertion
3461 above, is NARGS. */
3465 }
3467 /* Mark the template parameters. But this time, we're
3468 looking for the template parameters of the main
3469 template, not in the specialization. */
3476 NULL,
3480 {
3481 /* The type depended on some template parameters.
3482 If they are fully specialized in the
3483 specialization, that's OK. */
3488 {
3491 type,
3492 arg);
3494 }
3495 }
3496 }
3497 }
3498 }
3499 }
3503 /* We've already got this specialization. */
3511 }
3513 /* Check that a template declaration's use of default arguments and
3514 parameter packs is not invalid. Here, PARMS are the template
3515 parameters. IS_PRIMARY is nonzero if DECL is the thing declared by
3516 a primary template. IS_PARTIAL is nonzero if DECL is a partial
3517 specialization.
3520 IS_FRIEND_DECL is nonzero if DECL is a friend function template
3521 declaration (but not a definition); 1 indicates a declaration, 2
3522 indicates a redeclaration. When IS_FRIEND_DECL=2, no errors are
3523 emitted for extraneous default arguments.
3525 Returns TRUE if there were no errors found, FALSE otherwise. */
3527 bool
3530 {
3533 tree parm_level;
3536 /* [temp.param]
3538 A default template-argument shall not be specified in a
3539 function template declaration or a function template definition, nor
3540 in the template-parameter-list of the definition of a member of a
3541 class template. */
3544 /* You can't have a function template declaration in a local
3545 scope, nor you can you define a member of a class template in a
3546 local scope. */
3552 /* If this is either a friend defined in the scope of the class
3553 or a member function. */
3559 /* And, if it was a member function, it really was defined in
3560 the scope of the class. */
3563 /* We already checked these parameters when the template was
3564 declared, so there's no need to do it again now. This function
3565 was defined in class scope, but we're processing it's body now
3566 that the class is complete. */
3569 /* Core issue 226 (C++0x only): the following only applies to class
3570 templates. */
3572 {
3573 /* [temp.param]
3575 If a template-parameter has a default template-argument, all
3576 subsequent template-parameters shall have a default
3577 template-argument supplied. */
3579 {
3586 {
3596 {
3598 /* For better subsequent error-recovery, we indicate that
3599 there should have been a default argument. */
3602 }
3604 && !is_partial
3605 && !is_friend_decl
3606 /* Don't complain about an enclosing partial
3607 specialization. */
3612 {
3613 /* A primary class template can only have one
3614 parameter pack, at the end of the template
3615 parameter list. */
3620 else
3628 }
3629 }
3630 }
3631 }
3634 || is_partial
3635 || !is_primary
3637 /* For an ordinary class template, default template arguments are
3638 allowed at the innermost level, e.g.:
3639 template <class T = int>
3640 struct S {};
3641 but, in a partial specialization, they're not allowed even
3642 there, as we have in [temp.class.spec]:
3644 The template parameter list of a specialization shall not
3645 contain default template argument values.
3647 So, for a partial specialization, or for a function template
3648 (in C++98/C++03), we look at all of them. */
3649 ;
3650 else
3651 /* But, for a primary class template that is not a partial
3652 specialization we look at all template parameters except the
3653 innermost ones. */
3656 /* Figure out what error message to issue. */
3665 else
3669 /* If we're inside a class definition, there's no need to
3670 examine the parameters to the class itself. On the one
3671 hand, they will be checked when the class is defined, and,
3672 on the other, default arguments are valid in things like:
3673 template <class T = double>
3674 struct S { template <class U> void f(U); };
3675 Here the default argument for `S' has no bearing on the
3676 declaration of `f'. */
3678 else
3679 /* Check everything. */
3685 {
3692 {
3697 {
3699 {
3706 }
3708 /* Clear out the default argument so that we are not
3709 confused later. */
3711 }
3712 }
3714 /* At this point, if we're still interested in issuing messages,
3715 they must apply to classes surrounding the object declared. */
3718 }
3721 }
3723 /* Worker for push_template_decl_real, called via
3724 for_each_template_parm. DATA is really an int, indicating the
3725 level of the parameters we are interested in. If T is a template
3726 parameter of that level, return nonzero. */
3728 static int
3730 {
3736 else
3739 }
3741 /* Creates a TEMPLATE_DECL for the indicated DECL using the template
3742 parameters given by current_template_args, or reuses a
3743 previously existing one, if appropriate. Returns the DECL, or an
3744 equivalent one, if it is replaced via a call to duplicate_decls.
3746 If IS_FRIEND is true, DECL is a friend declaration. */
3748 tree
3750 {
3751 tree tmpl;
3752 tree args;
3753 tree info;
3754 tree ctx;
3758 /* True if the template is a member template, in the sense of
3759 [temp.mem]. */
3765 /* See if this is a partial specialization. */
3774 /* For a friend, we want the context of the friend function, not
3775 the type of which it is a friend. */
3779 /* In the case of a virtual function, we want the class in which
3780 it is defined. */
3782 else
3783 /* Otherwise, if we're currently defining some class, the DECL
3784 is assumed to be a member of the class. */
3793 /* See if this is a primary template. */
3795 /* A friend template that specifies a class context, i.e.
3796 template <typename T> friend void A<T>::f();
3797 is not primary. */
3799 else
3803 {
3808 {
3811 }
3813 {
3815 {
3816 /* [temp.mem]
3818 A destructor shall not be a member template. */
3821 }
3828 {
3829 /* [basic.stc.dynamic.allocation]
3831 An allocation function can be a function
3832 template. ... Template allocation functions shall
3833 have two or more parameters. */
3836 }
3837 }
3841 else
3842 {
3845 }
3846 }
3848 /* Check to see that the rules regarding the use of default
3849 arguments are not being violated. */
3853 /* Ensure that there are no parameter packs in the type of this
3854 declaration that have not been expanded. */
3856 {
3857 /* Check each of the arguments individually to see if there are
3858 any bare parameter packs. */
3864 {
3867 {
3868 /* This is a PARM_DECL that contains unexpanded parameter
3869 packs. We have already complained about this in the
3870 check_for_bare_parameter_packs call, so just replace
3871 these types with ERROR_MARK_NODE. */
3874 }
3878 }
3880 /* Check for bare parameter packs in the return type and the
3881 exception specifiers. */
3883 /* Errors were already issued, set return type to int
3884 as the frontend doesn't expect error_mark_node as
3885 the return type. */
3889 }
3891 {
3894 }
3905 {
3910 /* If DECL is a TYPE_DECL for a class-template, then there won't
3911 be DECL_LANG_SPECIFIC. The information equivalent to
3912 DECL_TEMPLATE_INFO is found in TYPE_TEMPLATE_INFO instead. */
3916 {
3917 /* Since a template declaration already existed for this
3918 class-type, we must be redeclaring it here. Make sure
3919 that the redeclaration is valid. */
3921 current_template_parms);
3922 /* We don't need to create a new TEMPLATE_DECL; just use the
3923 one we already had. */
3925 }
3926 else
3927 {
3929 member_template_p);
3934 {
3935 /* A specialization of a member template of a template
3936 class. */
3940 }
3941 }
3942 }
3943 else
3944 {
3950 {
3953 }
3961 {
3962 tree new_tmpl;
3964 /* The declaration is a specialization of a member
3965 template, declared outside the class. Therefore, the
3966 innermost template arguments will be NULL, so we
3967 replace them with the arguments determined by the
3968 earlier call to check_explicit_specialization. */
3971 new_tmpl
3973 member_template_p);
3983 args,
3984 is_friend);
3986 }
3988 /* Make sure the template headers we got make sense. */
3993 {
3996 }
3997 else
3999 {
4004 {
4008 else
4013 }
4017 else
4021 }
4023 /* Check that the parms are used in the appropriate qualifying scopes
4024 in the declarator. */
4028 {
4034 /* Avoid crash in import_export_decl. */
4037 }
4038 }
4043 /* Push template declarations for global functions and types. Note
4044 that we do not try to push a global template friend declared in a
4045 template class; such a thing may well depend on the template
4046 parameters of the class. */
4049 {
4054 /* Hide template friend classes that haven't been declared yet. */
4056 {
4059 }
4060 }
4063 {
4069 {
4072 /* It is a conversion operator. See if the type converted to
4073 depends on innermost template operands. */
4076 depth))
4078 }
4080 /* Give template template parms a DECL_CONTEXT of the template
4081 for which they are a parameter. */
4084 {
4088 }
4089 }
4091 /* The DECL_TI_ARGS of DECL contains full set of arguments referring
4092 back to its most general template. If TMPL is a specialization,
4093 ARGS may only have the innermost set of arguments. Add the missing
4094 argument levels if necessary. */
4106 }
4108 tree
4110 {
4112 }
4114 /* Called when a class template TYPE is redeclared with the indicated
4115 template PARMS, e.g.:
4117 template <class T> struct S;
4118 template <class T> struct S {}; */
4120 bool
4122 {
4123 tree tmpl;
4124 tree tmpl_parms;
4128 {
4131 }
4135 /* The type is nested in some template class. Nothing to worry
4136 about here; there are no new template parameters for the nested
4137 type. */
4141 {
4143 tmpl);
4145 }
4151 {
4157 }
4160 {
4161 tree tmpl_parm;
4162 tree parm;
4163 tree tmpl_default;
4164 tree parm_default;
4175 /* TMPL_PARM and PARM can be either TYPE_DECL, PARM_DECL, or
4176 TEMPLATE_DECL. */
4187 {
4191 }
4194 {
4195 /* We have in [temp.param]:
4197 A template-parameter may not be given default arguments
4198 by two different declarations in the same scope. */
4202 }
4205 /* Update the previous template parameters (which are the ones
4206 that will really count) with the new default value. */
4209 /* Update the new parameters, too; they'll be used as the
4210 parameters for any members. */
4212 }
4215 }
4217 /* Simplify EXPR if it is a non-dependent expression. Returns the
4218 (possibly simplified) expression. */
4220 tree
4222 {
4226 /* If we're in a template, but EXPR isn't value dependent, simplify
4227 it. We're supposed to treat:
4229 template <typename T> void f(T[1 + 1]);
4230 template <typename T> void f(T[2]);
4232 as two declarations of the same function, for example. */
4236 {
4237 HOST_WIDE_INT saved_processing_template_decl;
4243 tf_error,
4248 }
4250 }
4252 /* EXPR is an expression which is used in a constant-expression context.
4253 For instance, it could be a VAR_DECL with a constant initializer.
4254 Extract the innermost constant expression.
4256 This is basically a more powerful version of
4257 integral_constant_value, which can be used also in templates where
4258 initializers can maintain a syntactic rather than semantic form
4259 (even if they are non-dependent, for access-checking purposes). */
4261 static tree
4263 {
4265 do
4266 {
4269 }
4273 }
4275 /* Subroutine of convert_nontype_argument. Converts EXPR to TYPE, which
4276 must be a function or a pointer-to-function type, as specified
4277 in [temp.arg.nontype]: disambiguate EXPR if it is an overload set,
4278 and check that the resulting function has external linkage. */
4280 static tree
4282 {
4296 /* [temp.arg.nontype]/1
4298 A template-argument for a non-type, non-template template-parameter
4299 shall be one of:
4300 [...]
4301 -- the address of an object or function with external linkage. */
4303 {
4308 }
4311 }
4313 /* Attempt to convert the non-type template parameter EXPR to the
4314 indicated TYPE. If the conversion is successful, return the
4315 converted value. If the conversion is unsuccessful, return
4316 NULL_TREE if we issued an error message, or error_mark_node if we
4317 did not. We issue error messages for out-and-out bad template
4318 parameters, but not simply because the conversion failed, since we
4319 might be just trying to do argument deduction. Both TYPE and EXPR
4320 must be non-dependent.
4322 The conversion follows the special rules described in
4323 [temp.arg.nontype], and it is much more strict than an implicit
4324 conversion.
4326 This function is called twice for each template argument (see
4327 lookup_template_class for a more accurate description of this
4328 problem). This means that we need to handle expressions which
4329 are not valid in a C++ source, but can be created from the
4330 first call (for instance, casts to perform conversions). These
4331 hacks can go away after we fix the double coercion problem. */
4333 static tree
4335 {
4336 tree expr_type;
4338 /* Detect immediately string literals as invalid non-type argument.
4339 This special-case is not needed for correctness (we would easily
4340 catch this later), but only to provide better diagnostic for this
4341 common user mistake. As suggested by DR 100, we do not mention
4342 linkage issues in the diagnostic as this is not the point. */
4344 {
4349 }
4351 /* If we are in a template, EXPR may be non-dependent, but still
4352 have a syntactic, rather than semantic, form. For example, EXPR
4353 might be a SCOPE_REF, rather than the VAR_DECL to which the
4354 SCOPE_REF refers. Preserving the qualifying scope is necessary
4355 so that access checking can be performed when the template is
4356 instantiated -- but here we need the resolved form so that we can
4357 convert the argument. */
4363 /* HACK: Due to double coercion, we can get a
4364 NOP_EXPR<REFERENCE_TYPE>(ADDR_EXPR<POINTER_TYPE> (arg)) here,
4365 which is the tree that we built on the first call (see
4366 below when coercing to reference to object or to reference to
4367 function). We just strip everything and get to the arg.
4368 See g++.old-deja/g++.oliva/template4.C and g++.dg/template/nontype9.C
4369 for examples. */
4371 {
4373 {
4374 /* ??? Maybe we could use convert_from_reference here, but we
4375 would need to relax its constraints because the NOP_EXPR
4376 could actually change the type to something more cv-qualified,
4377 and this is not folded by convert_from_reference. */
4388 }
4390 /* We could also generate a NOP_EXPR(ADDR_EXPR()) when the
4391 parameter is a pointer to object, through decay and
4392 qualification conversion. Let's strip everything. */
4394 {
4398 /* Skip the ADDR_EXPR only if it is part of the decay for
4399 an array. Otherwise, it is part of the original argument
4400 in the source code. */
4404 }
4405 }
4407 /* [temp.arg.nontype]/5, bullet 1
4409 For a non-type template-parameter of integral or enumeration type,
4410 integral promotions (_conv.prom_) and integral conversions
4411 (_conv.integral_) are applied. */
4413 {
4418 /* Notice that there are constant expressions like '4 % 0' which
4419 do not fold into integer constants. */
4421 {
4425 }
4427 /* At this point, an implicit conversion does what we want,
4428 because we already know that the expression is of integral
4429 type. */
4434 /* Conversion was allowed: fold it to a bare integer constant. */
4436 }
4437 /* [temp.arg.nontype]/5, bullet 2
4439 For a non-type template-parameter of type pointer to object,
4440 qualification conversions (_conv.qual_) and the array-to-pointer
4441 conversion (_conv.array_) are applied. */
4443 {
4444 /* [temp.arg.nontype]/1 (TC1 version, DR 49):
4446 A template-argument for a non-type, non-template template-parameter
4447 shall be one of: [...]
4449 -- the name of a non-type template-parameter;
4450 -- the address of an object or function with external linkage, [...]
4451 expressed as "& id-expression" where the & is optional if the name
4452 refers to a function or array, or if the corresponding
4453 template-parameter is a reference.
4455 Here, we do not care about functions, as they are invalid anyway
4456 for a parameter of type pointer-to-object. */
4459 /* Non-type template parameters are OK. */
4460 ;
4463 {
4465 {
4467 "because %qD is a variable, not the address of "
4471 }
4472 /* Other values, like integer constants, might be valid
4473 non-type arguments of some other type. */
4475 }
4476 else
4477 {
4478 tree decl;
4483 {
4488 }
4490 {
4495 }
4496 }
4505 }
4506 /* [temp.arg.nontype]/5, bullet 3
4508 For a non-type template-parameter of type reference to object, no
4509 conversions apply. The type referred to by the reference may be more
4510 cv-qualified than the (otherwise identical) type of the
4511 template-argument. The template-parameter is bound directly to the
4512 template-argument, which must be an lvalue. */
4514 {
4516 expr_type))
4520 {
4524 }
4527 {
4531 }
4533 /* [temp.arg.nontype]/1
4535 A template-argument for a non-type, non-template template-parameter
4536 shall be one of: [...]
4538 -- the address of an object or function with external linkage. */
4540 {
4545 }
4548 }
4549 /* [temp.arg.nontype]/5, bullet 4
4551 For a non-type template-parameter of type pointer to function, only
4552 the function-to-pointer conversion (_conv.func_) is applied. If the
4553 template-argument represents a set of overloaded functions (or a
4554 pointer to such), the matching function is selected from the set
4555 (_over.over_). */
4557 {
4558 /* If the argument is a template-id, we might not have enough
4559 context information to decay the pointer. */
4561 {
4565 }
4572 {
4576 }
4577 }
4578 /* [temp.arg.nontype]/5, bullet 5
4580 For a non-type template-parameter of type reference to function, no
4581 conversions apply. If the template-argument represents a set of
4582 overloaded functions, the matching function is selected from the set
4583 (_over.over_). */
4585 {
4587 {
4592 }
4599 }
4600 /* [temp.arg.nontype]/5, bullet 6
4602 For a non-type template-parameter of type pointer to member function,
4603 no conversions apply. If the template-argument represents a set of
4604 overloaded member functions, the matching member function is selected
4605 from the set (_over.over_). */
4607 {
4612 /* There is no way to disable standard conversions in
4613 resolve_address_of_overloaded_function (called by
4614 instantiate_type). It is possible that the call succeeded by
4615 converting &B::I to &D::I (where B is a base of D), so we need
4616 to reject this conversion here.
4618 Actually, even if there was a way to disable standard conversions,
4619 it would still be better to reject them here so that we can
4620 provide a superior diagnostic. */
4622 {
4623 /* Make sure we are just one standard conversion off. */
4630 }
4631 }
4632 /* [temp.arg.nontype]/5, bullet 7
4634 For a non-type template-parameter of type pointer to data member,
4635 qualification conversions (_conv.qual_) are applied. */
4637 {
4641 }
4642 /* A template non-type parameter must be one of the above. */
4643 else
4646 /* Sanity check: did we actually convert the argument to the
4647 right type? */
4650 }
4652 /* Subroutine of coerce_template_template_parms, which returns 1 if
4653 PARM_PARM and ARG_PARM match using the rule for the template
4654 parameters of template template parameters. Both PARM and ARG are
4655 template parameters; the rest of the arguments are the same as for
4656 coerce_template_template_parms.
4657 */
4658 static int
4660 tree arg,
4661 tsubst_flags_t complain,
4662 tree in_decl,
4663 tree outer_args)
4664 {
4673 {
4675 /* We encounter instantiations of templates like
4676 template <template <template <class> class> class TT>
4677 class C; */
4678 {
4685 }
4686 /* Fall through. */
4691 /* Argument is a parameter pack but parameter is not. */
4696 /* The tsubst call is used to handle cases such as
4698 template <int> class C {};
4699 template <class T, template <T> class TT> class D {};
4700 D<int, C> d;
4702 i.e. the parameter list of TT depends on earlier parameters. */
4704 && !same_type_p
4711 /* Argument is a parameter pack but parameter is not. */
4718 }
4721 }
4724 /* Return 1 if PARM_PARMS and ARG_PARMS matches using rule for
4725 template template parameters. Both PARM_PARMS and ARG_PARMS are
4726 vectors of TREE_LIST nodes containing TYPE_DECL, TEMPLATE_DECL
4727 or PARM_DECL.
4729 Consider the example:
4730 template <class T> class A;
4731 template<template <class U> class TT> class B;
4733 For B<A>, PARM_PARMS are the parameters to TT, while ARG_PARMS are
4734 the parameters to A, and OUTER_ARGS contains A. */
4736 static int
4738 tree arg_parms,
4739 tsubst_flags_t complain,
4740 tree in_decl,
4741 tree outer_args)
4742 {
4753 /* Determine whether we have a parameter pack at the end of the
4754 template template parameter's template parameter list. */
4756 {
4763 {
4777 }
4778 }
4784 /* Check all of the template parameters except the parameter pack at
4785 the end (if any). */
4787 {
4796 outer_args))
4799 }
4802 {
4803 /* Check each of the template parameters in the template
4804 argument against the template parameter pack at the end of
4805 the template template parameter. */
4812 {
4819 outer_args))
4821 }
4822 }
4825 }
4827 /* Verifies that the deduced template arguments (in TARGS) for the
4828 template template parameters (in TPARMS) represent valid bindings,
4829 by comparing the template parameter list of each template argument
4830 to the template parameter list of its corresponding template
4831 template parameter, in accordance with DR150. This
4832 routine can only be called after all template arguments have been
4833 deduced. It will return TRUE if all of the template template
4834 parameter bindings are okay, FALSE otherwise. */
4835 bool
4837 {
4841 /* We're dealing with template parms in this process. */
4847 {
4852 {
4857 {
4858 /* Look inside the argument pack. */
4861 }
4864 {
4868 /* Extract the next argument from the argument
4869 pack. */
4873 /* Look at the pattern of the pack expansion. */
4876 /* Extract the template parameters from the template
4877 argument. */
4883 /* Verify that we can coerce the template template
4884 parameters from the template argument to the template
4885 parameter. This requires an exact match. */
4887 && !coerce_template_template_parms
4889 targ_parms,
4890 tf_none,
4891 tparm,
4892 targs))
4893 {
4896 }
4897 }
4898 }
4899 }
4901 out:
4905 }
4907 /* Convert the indicated template ARG as necessary to match the
4908 indicated template PARM. Returns the converted ARG, or
4909 error_mark_node if the conversion was unsuccessful. Error and
4910 warning messages are issued under control of COMPLAIN. This
4911 conversion is for the Ith parameter in the parameter list. ARGS is
4912 the full set of template arguments deduced so far. */
4914 static tree
4916 tree arg,
4917 tree args,
4918 tsubst_flags_t complain,
4920 tree in_decl)
4921 {
4922 tree orig_arg;
4923 tree val;
4928 {
4929 /* The template argument was the name of some
4930 member function. That's usually
4931 invalid, but static members are OK. In any
4932 case, grab the underlying fields/functions
4933 and issue an error later if required. */
4936 }
4944 /* When determining whether an argument pack expansion is a template,
4945 look at the pattern. */
4949 is_tmpl_type =
4964 {
4970 typename_type,
4974 }
4976 {
4978 {
4980 {
4990 else
4992 }
4993 }
4995 }
4997 {
4999 {
5005 else
5007 }
5009 }
5012 {
5014 {
5016 /* The number of argument required is not known yet.
5017 Just accept it for now. */
5019 else
5020 {
5022 tree argparm;
5028 args))
5029 {
5032 /* TEMPLATE_TEMPLATE_PARM node is preferred over
5033 TEMPLATE_DECL. */
5035 {
5040 {
5043 }
5044 }
5045 }
5046 else
5047 {
5049 {
5055 }
5058 }
5059 }
5060 }
5061 else
5063 /* We only form one instance of each template specialization.
5064 Therefore, if we use a non-canonical variant (i.e., a
5065 typedef), any future messages referring to the type will use
5066 the typedef, which is confusing if those future uses do not
5067 themselves also use the typedef. */
5070 }
5071 else
5072 {
5079 {
5082 else
5083 {
5084 /* Not sure if this is reachable, but it doesn't hurt
5085 to be robust. */
5088 }
5089 }
5091 /* We used to call digest_init here. However, digest_init
5092 will report errors, which we don't want when complain
5093 is zero. More importantly, digest_init will try too
5094 hard to convert things: for example, `0' should not be
5095 converted to pointer type at this point according to
5096 the standard. Accepting this is not merely an
5097 extension, since deciding whether or not these
5098 conversions can occur is part of determining which
5099 function template to call, or whether a given explicit
5100 argument specification is valid. */
5102 else
5109 }
5112 }
5114 /* Coerces the remaining template arguments in INNER_ARGS (from
5115 ARG_IDX to the end) into the parameter pack at PARM_IDX in PARMS.
5116 Returns the coerced argument pack. PARM_IDX is the position of this
5117 parameter in the template parameter list. ARGS is the original
5118 template argument list. */
5119 static tree
5122 tree args,
5123 tree inner_args,
5125 tree new_args,
5127 tree in_decl,
5128 tsubst_flags_t complain)
5129 {
5132 tree packed_args;
5133 tree argument_pack;
5143 {
5144 /* When the template parameter is a non-type template
5145 parameter pack whose type uses parameter packs, we need
5146 to look at each of the template arguments
5147 separately. Build a vector of the types for these
5148 non-type template parameters in PACKED_TYPES. */
5149 tree expansion
5157 /* Check that we have the right number of arguments. */
5161 {
5162 int needed_parms
5167 }
5169 /* If we aren't able to check the actual arguments now
5170 (because they haven't been expanded yet), we can at least
5171 verify that all of the types used for the non-type
5172 template parameter pack are, in fact, valid for non-type
5173 template parameters. */
5176 {
5179 {
5183 }
5184 }
5185 }
5187 /* Convert the remaining arguments, which will be a part of the
5188 parameter pack "parm". */
5190 {
5195 {
5196 /* When we have a vector of types (corresponding to the
5197 non-type template parameter pack that uses parameter
5198 packs in its type, as mention above), and the
5199 argument is not an expansion (which expands to a
5200 currently unknown number of arguments), clone the
5201 parm and give it the next type in PACKED_TYPES. */
5205 }
5210 in_decl);
5214 }
5219 else
5220 {
5225 }
5229 }
5231 /* Convert all template arguments to their appropriate types, and
5232 return a vector containing the innermost resulting template
5233 arguments. If any error occurs, return error_mark_node. Error and
5234 warning messages are issued under control of COMPLAIN.
5236 If REQUIRE_ALL_ARGS is false, argument deduction will be performed
5237 for arguments not specified in ARGS. Otherwise, if
5238 USE_DEFAULT_ARGS is true, default arguments will be used to fill in
5239 unspecified arguments. If REQUIRE_ALL_ARGS is true, but
5240 USE_DEFAULT_ARGS is false, then all arguments must be specified in
5241 ARGS. */
5243 static tree
5245 tree args,
5246 tree in_decl,
5247 tsubst_flags_t complain,
5250 {
5252 tree inner_args;
5253 tree new_args;
5254 tree new_inner_args;
5257 /* When used as a boolean value, indicates whether this is a
5258 variadic template parameter list. Since it's an int, we can also
5259 subtract it from nparms to get the number of non-variadic
5260 parameters. */
5265 /* Determine if there are any parameter packs. */
5267 {
5271 }
5274 /* If there are 0 or 1 parameter packs, we need to expand any argument
5275 packs so that we can deduce a parameter pack from some non-packed args
5276 followed by an argument pack, as in variadic85.C. If there are more
5277 than that, we need to leave argument packs intact so the arguments are
5278 assigned to the right parameter packs. This should only happen when
5279 dealing with a nested class inside a partial specialization of a class
5280 template, as in variadic92.C. */
5287 && require_all_args
5288 && (!use_default_args
5291 {
5293 {
5296 {
5299 }
5306 }
5309 }
5311 /* We need to evaluate the template arguments, even though this
5312 template-id may be nested within a "sizeof". */
5318 {
5319 tree arg;
5320 tree parm;
5322 /* Get the Ith template parameter. */
5326 {
5329 }
5331 /* Calculate the next argument. */
5334 else
5339 {
5340 /* All remaining arguments will be placed in the
5341 template parameter pack PARM. */
5347 /* Store this argument. */
5349 lost++;
5352 /* We are done with all of the arguments. */
5356 }
5358 {
5360 {
5362 {
5363 /* FIXME this restriction was removed by N2555; see
5364 bug 35722. */
5365 /* If ARG is a pack expansion, but PARM is not a
5366 template parameter pack (if it were, we would have
5367 handled it above), we're trying to expand into a
5368 fixed-length argument list. */
5372 else
5375 }
5377 }
5378 }
5380 /* There must be a default arg in this case. */
5383 else
5387 {
5390 }
5392 /* This only occurs if there was an error in the template
5393 parameter list itself (which we would already have
5394 reported) that we are trying to recover from, e.g., a class
5395 template with a parameter list such as
5396 template<typename..., typename>. */
5398 else
5404 lost++;
5406 }
5413 }
5415 /* Returns 1 if template args OT and NT are equivalent. */
5417 static int
5419 {
5424 /* For member templates */
5431 {
5448 }
5453 else
5455 }
5457 /* Returns 1 iff the OLDARGS and NEWARGS are in fact identical sets
5458 of template arguments. Returns 0 otherwise. */
5460 int
5462 {
5469 {
5475 }
5477 }
5479 static void
5481 {
5491 /* We are called both from instantiate_decl, where we've already had a
5492 tinst_level pushed, and instantiate_template, where we haven't.
5493 Compensate. */
5504 else
5513 }
5516 /* Return a TEMPLATE_ID_EXPR corresponding to the indicated FNS and
5517 ARGLIST. Valid choices for FNS are given in the cp-tree.def
5518 documentation for TEMPLATE_ID_EXPR. */
5520 tree
5522 {
5523 tree type;
5533 {
5535 unknown_type_node,
5537 arglist);
5539 }
5546 }
5548 /* Within the scope of a template class S<T>, the name S gets bound
5549 (in build_self_reference) to a TYPE_DECL for the class, not a
5550 TEMPLATE_DECL. If DECL is a TYPE_DECL for current_class_type,
5551 or one of its enclosing classes, and that type is a template,
5552 return the associated TEMPLATE_DECL. Otherwise, the original
5553 DECL is returned. */
5555 tree
5557 {
5564 }
5566 /* Given an IDENTIFIER_NODE (type TEMPLATE_DECL) and a chain of
5567 parameters, find the desired type.
5569 D1 is the PTYPENAME terminal, and ARGLIST is the list of arguments.
5571 IN_DECL, if non-NULL, is the template declaration we are trying to
5572 instantiate.
5574 If ENTERING_SCOPE is nonzero, we are about to enter the scope of
5575 the class we are looking up.
5577 Issue error and warning messages under control of COMPLAIN.
5579 If the template class is really a local class in a template
5580 function, then the FUNCTION_CONTEXT is the function in which it is
5581 being instantiated.
5583 ??? Note that this function is currently called *twice* for each
5584 template-id: the first time from the parser, while creating the
5585 incomplete type (finish_template_type), and the second type during the
5586 real instantiation (instantiate_template_class). This is surely something
5587 that we want to avoid. It also causes some problems with argument
5588 coercion (see convert_nontype_argument for more information on this). */
5590 tree
5592 tree arglist,
5593 tree in_decl,
5594 tree context,
5596 tsubst_flags_t complain)
5597 {
5599 tree t;
5604 {
5608 else
5609 {
5616 }
5619 }
5621 {
5624 /* If we are declaring a constructor, say A<T>::A<T>, we will get
5625 an implicit typename for the second A. Deal with it. */
5630 {
5633 }
5634 }
5637 {
5640 }
5644 {
5648 }
5650 /* Issue an error message if we didn't find a template. */
5652 {
5656 }
5659 /* Make sure it's a user visible template, if it was named by
5660 the user. */
5663 {
5665 {
5669 }
5671 }
5676 {
5677 /* Create a new TEMPLATE_DECL and TEMPLATE_TEMPLATE_PARM node to store
5678 template arguments */
5680 tree parm;
5681 tree arglist2;
5682 tree outer;
5686 /* Consider an example where a template template parameter declared as
5688 template <class T, class U = std::allocator<T> > class TT
5690 The template parameter level of T and U are one level larger than
5691 of TT. To proper process the default argument of U, say when an
5692 instantiation `TT<int>' is seen, we need to build the full
5693 arguments containing {int} as the innermost level. Outer levels,
5694 available when not appearing as default template argument, can be
5695 obtained from the arguments of the enclosing template.
5697 Suppose that TT is later substituted with std::vector. The above
5698 instantiation is `TT<int, std::allocator<T> >' with TT at
5699 level 1, and T at level 2, while the template arguments at level 1
5700 becomes {std::vector} and the inner level 2 is {int}. */
5706 /* This is an argument of the current template, so we haven't set
5707 DECL_CONTEXT yet. */
5714 complain,
5724 }
5725 else
5726 {
5728 tree gen_tmpl;
5729 tree type_decl;
5741 {
5742 /* We've been given an incomplete set of template arguments.
5743 For example, given:
5745 template <class T> struct S1 {
5746 template <class U> struct S2 {};
5747 template <class U> struct S2<U*> {};
5748 };
5750 we will be called with an ARGLIST of `U*', but the
5751 TEMPLATE will be `template <class T> template
5752 <class U> struct S1<T>::S2'. We must fill in the missing
5753 arguments. */
5754 arglist
5756 arglist);
5758 }
5760 /* Now we should have enough arguments. */
5763 /* From here on, we're only interested in the most general
5764 template. */
5767 /* Calculate the BOUND_ARGS. These will be the args that are
5768 actually tsubst'd into the definition to create the
5769 instantiation. */
5771 {
5772 /* We have multiple levels of arguments to coerce, at once. */
5782 {
5785 complain,
5789 /* Don't process further if one of the levels fails. */
5791 {
5792 /* Restore the ARGLIST to its full size. */
5795 }
5799 /* We temporarily reduce the length of the ARGLIST so
5800 that coerce_template_parms will see only the arguments
5801 corresponding to the template parameters it is
5802 examining. */
5804 }
5806 /* Restore the ARGLIST to its full size. */
5810 }
5811 else
5812 arglist
5815 templ,
5816 complain,
5821 /* We were unable to bind the arguments. */
5824 /* In the scope of a template class, explicit references to the
5825 template class refer to the type of the template, not any
5826 instantiation of it. For example, in:
5828 template <class T> class C { void f(C<T>); }
5830 the `C<T>' is just the same as `C'. Outside of the
5831 class, however, such a reference is an instantiation. */
5833 arglist))
5834 {
5838 {
5839 tree ctx;
5849 /* We're not in the scope of the class, so the
5850 TEMPLATE_TYPE is not the type we want after all. */
5852 found_ctx:;
5853 }
5854 }
5858 /* If we already have this specialization, return it. */
5864 /* This type is a "partial instantiation" if any of the template
5865 arguments still involve template parameters. Note that we set
5866 IS_PARTIAL_INSTANTIATION for partial specializations as
5867 well. */
5870 /* If the deduced arguments are invalid, then the binding
5871 failed. */
5875 complain))
5881 {
5886 }
5893 /* Create the type. */
5895 {
5897 {
5903 }
5904 else
5905 {
5906 /* We don't want to call start_enum for this type, since
5907 the values for the enumeration constants may involve
5908 template parameters. And, no one should be interested
5909 in the enumeration constants for such a type. */
5912 }
5913 }
5914 else
5915 {
5922 /* A local class. Make sure the decl gets registered properly. */
5927 /* This instantiation is another name for the primary
5928 template type. Set the TYPE_CANONICAL field
5929 appropriately. */
5932 /* Some of the template arguments require structural
5933 equality testing, so this template class requires
5934 structural equality testing. */
5936 }
5938 /* If we called start_enum or pushtag above, this information
5939 will already be set up. */
5941 {
5949 }
5950 else
5958 {
5961 }
5963 /* Set up the template information. We have to figure out which
5964 template is the immediate parent if this is a full
5965 instantiation. */
5968 /* This case is easy; there are no member templates involved. */
5970 else
5971 {
5972 /* This is a full instantiation of a member template. Look
5973 for a partial instantiation of which this is an instance. */
5977 {
5981 /* We only want partial instantiations, here, not
5982 specializations or full instantiations. */
5987 /* Temporarily reduce by one the number of levels in the
5988 ARGLIST and in FOUND so as to avoid comparing the
5989 last set of arguments. */
5993 /* See if the arguments match. If they do, then TMPL is
5994 the partial instantiation we want. */
5997 /* Restore the argument vectors to their full size. */
6002 {
6005 }
6006 }
6009 {
6010 /* There was no partial instantiation. This happens
6011 where C<T> is a member template of A<T> and it's used
6012 in something like
6014 template <typename T> struct B { A<T>::C<int> m; };
6015 B<float>;
6017 Create the partial instantiation.
6018 */
6022 }
6023 }
6032 /* Now that the type has been registered on the instantiations
6033 list, we set up the enumerators. Because the enumeration
6034 constants may involve the enumeration type itself, we make
6035 sure to register the type first, and then create the
6036 constants. That way, doing tsubst_expr for the enumeration
6037 constants won't result in recursive calls here; we'll find
6038 the instantiation and exit above. */
6042 /* If the type makes use of template parameters, the
6043 code that generates debugging information will crash. */
6046 /* Possibly limit visibility based on template args. */
6051 }
6053 }
6054 \f
6055 struct pair_fn_data
6056 {
6057 tree_fn_t fn;
6059 /* True when we should also visit template parameters that occur in
6060 non-deduced contexts. */
6063 };
6065 /* Called from for_each_template_parm via walk_tree. */
6067 static tree
6069 {
6082 {
6086 /* Fall through. */
6109 /* Since we're not going to walk subtrees, we have to do this
6110 explicitly here. */
6114 /* Fall through. */
6117 /* Check the return type. */
6122 /* Check the parameter types. Since default arguments are not
6123 instantiated until they are needed, the TYPE_ARG_TYPES may
6124 contain expressions that involve template parameters. But,
6125 no-one should be looking at them yet. And, once they're
6126 instantiated, they don't contain template parameters, so
6127 there's no point in looking at them then, either. */
6128 {
6129 tree parm;
6136 /* Since we've already handled the TYPE_ARG_TYPES, we don't
6137 want walk_tree walking into them itself. */
6139 }
6156 /* Fall through. */
6172 /* Record template parameters such as `T' inside `TT<T>'. */
6176 /* Fall through. */
6188 /* A template template parameter is encountered. */
6194 /* Already substituted template template parameter */
6217 /* If there's no type, then this thing must be some expression
6218 involving template parameters. */
6239 }
6241 /* We didn't find any template parameters we liked. */
6243 }
6245 /* For each TEMPLATE_TYPE_PARM, TEMPLATE_TEMPLATE_PARM,
6246 BOUND_TEMPLATE_TEMPLATE_PARM or TEMPLATE_PARM_INDEX in T,
6247 call FN with the parameter and the DATA.
6248 If FN returns nonzero, the iteration is terminated, and
6249 for_each_template_parm returns 1. Otherwise, the iteration
6250 continues. If FN never returns a nonzero value, the value
6251 returned by for_each_template_parm is 0. If FN is NULL, it is
6252 considered to be the function which always returns 1.
6254 If INCLUDE_NONDEDUCED_P, then this routine will also visit template
6255 parameters that occur in non-deduced contexts. When false, only
6256 visits those template parameters that can be deduced. */
6258 static int
6262 {
6266 /* Set up. */
6271 /* Walk the tree. (Conceptually, we would like to walk without
6272 duplicates, but for_each_template_parm_r recursively calls
6273 for_each_template_parm, so we would need to reorganize a fair
6274 bit to use walk_tree_without_duplicates, so we keep our own
6275 visited list.) */
6278 else
6281 for_each_template_parm_r,
6285 /* Clean up. */
6287 {
6290 }
6293 }
6295 /* Returns true if T depends on any template parameter. */
6297 int
6299 {
6325 else
6326 {
6329 }
6334 }
6336 /* Returns true if T depends on any template parameter with level LEVEL. */
6338 int
6340 {
6343 }
6347 #ifdef GATHER_STATISTICS
6349 #endif
6353 /* We're starting to instantiate D; record the template instantiation context
6354 for diagnostics and to restore it later. */
6356 static int
6358 {
6362 {
6363 /* If the instantiation in question still has unbound template parms,
6364 we don't really care if we can't instantiate it, so just return.
6365 This happens with base instantiation for implicit `typename'. */
6377 }
6387 #ifdef GATHER_STATISTICS
6390 #endif
6394 }
6396 /* We're done instantiating this template; return to the instantiation
6397 context. */
6399 static void
6401 {
6402 /* Restore the filename and line number stashed away when we started
6403 this instantiation. */
6408 }
6410 /* We're instantiating a deferred template; restore the template
6411 instantiation context in which the instantiation was requested, which
6412 is one step out from LEVEL. Return the corresponding DECL or TYPE. */
6414 static tree
6416 {
6426 }
6428 /* Returns the TINST_LEVEL which gives the original instantiation
6429 context. */
6433 {
6439 }
6441 /* Returns TRUE if PARM is a parameter of the template TEMPL. */
6443 bool
6445 {
6446 tree parms;
6463 }
6465 /* DECL is a friend FUNCTION_DECL or TEMPLATE_DECL. ARGS is the
6466 vector of template arguments, as for tsubst.
6468 Returns an appropriate tsubst'd friend declaration. */
6470 static tree
6472 {
6473 tree new_friend;
6478 /* This was a friend declared with an explicit template
6479 argument list, e.g.:
6481 friend void f<>(T);
6483 to indicate that f was a template instantiation, not a new
6484 function declaration. Now, we have to figure out what
6485 instantiation of what template. */
6486 {
6488 tree new_args;
6489 tree tmpl;
6492 /* Friend functions are looked up in the containing namespace scope.
6493 We must enter that scope, to avoid finding member functions of the
6494 current class with same name. */
6509 tsk_none);
6511 }
6515 /* The NEW_FRIEND will look like an instantiation, to the
6516 compiler, but is not an instantiation from the point of view of
6517 the language. For example, we might have had:
6519 template <class T> struct S {
6520 template <class U> friend void f(T, U);
6521 };
6523 Then, in S<int>, template <class U> void f(int, U) is not an
6524 instantiation of anything. */
6530 {
6534 }
6536 /* The mangled name for the NEW_FRIEND is incorrect. The function
6537 is not a template instantiation and should not be mangled like
6538 one. Therefore, we forget the mangling here; we'll recompute it
6539 later if we need it. */
6541 {
6544 }
6547 {
6548 tree old_decl;
6549 tree new_friend_template_info;
6550 tree new_friend_result_template_info;
6551 tree ns;
6554 /* We must save some information from NEW_FRIEND before calling
6555 duplicate decls since that function will free NEW_FRIEND if
6556 possible. */
6558 new_friend_is_defn =
6563 {
6564 /* This declaration is a `primary' template. */
6567 new_friend_result_template_info
6569 }
6570 else
6573 /* Make the init_value nonzero so pushdecl knows this is a defn. */
6577 /* Inside pushdecl_namespace_level, we will push into the
6578 current namespace. However, the friend function should go
6579 into the namespace of the template. */
6589 {
6590 /* This new friend declaration matched an existing
6591 declaration. For example, given:
6593 template <class T> void f(T);
6594 template <class U> class C {
6595 template <class T> friend void f(T) {}
6596 };
6598 the friend declaration actually provides the definition
6599 of `f', once C has been instantiated for some type. So,
6600 old_decl will be the out-of-class template declaration,
6601 while new_friend is the in-class definition.
6603 But, if `f' was called before this point, the
6604 instantiation of `f' will have DECL_TI_ARGS corresponding
6605 to `T' but not to `U', references to which might appear
6606 in the definition of `f'. Previously, the most general
6607 template for an instantiation of `f' was the out-of-class
6608 version; now it is the in-class version. Therefore, we
6609 run through all specialization of `f', adding to their
6610 DECL_TI_ARGS appropriately. In particular, they need a
6611 new set of outer arguments, corresponding to the
6612 arguments for this class instantiation.
6614 The same situation can arise with something like this:
6616 friend void f(int);
6617 template <class T> class C {
6618 friend void f(T) {}
6619 };
6621 when `C<int>' is instantiated. Now, `f(int)' is defined
6622 in the class. */
6625 /* On the other hand, if the in-class declaration does
6626 *not* provide a definition, then we don't want to alter
6627 existing definitions. We can just leave everything
6628 alone. */
6629 ;
6630 else
6631 {
6632 /* Overwrite whatever template info was there before, if
6633 any, with the new template information pertaining to
6634 the declaration. */
6640 old_decl);
6641 else
6642 {
6643 tree t;
6644 tree new_friend_args;
6653 {
6659 }
6661 /* Now, since specializations are always supposed to
6662 hang off of the most general template, we must move
6663 them. */
6666 {
6671 }
6672 }
6673 }
6675 /* The information from NEW_FRIEND has been merged into OLD_DECL
6676 by duplicate_decls. */
6678 }
6679 }
6680 else
6681 {
6685 /* In the code
6686 template <class T> class C {
6687 template <class U> friend void C1<U>::f (); // case 1
6688 friend void C2<T>::f (); // case 2
6689 };
6690 we only need to make sure CONTEXT is a complete type for
6691 case 2. To distinguish between the two cases, we note that
6692 CONTEXT of case 1 remains dependent type after tsubst while
6693 this isn't true for case 2. */
6703 {
6704 /* Check to see that the declaration is really present, and,
6705 possibly obtain an improved declaration. */
6711 }
6712 }
6715 }
6717 /* FRIEND_TMPL is a friend TEMPLATE_DECL. ARGS is the vector of
6718 template arguments, as for tsubst.
6720 Returns an appropriate tsubst'd friend type or error_mark_node on
6721 failure. */
6723 static tree
6725 {
6726 tree friend_type;
6727 tree tmpl;
6728 tree context;
6733 {
6736 else
6738 }
6740 /* Look for a class template declaration. We look for hidden names
6741 because two friend declarations of the same template are the
6742 same. For example, in:
6744 struct A {
6745 template <typename> friend class F;
6746 };
6747 template <typename> struct B {
6748 template <typename> friend class F;
6749 };
6751 both F templates are the same. */
6756 /* But, if we don't find one, it might be because we're in a
6757 situation like this:
6759 template <class T>
6760 struct S {
6761 template <class U>
6762 friend struct S;
6763 };
6765 Here, in the scope of (say) S<int>, `S' is bound to a TYPE_DECL
6766 for `S<int>', not the TEMPLATE_DECL. */
6768 {
6771 }
6774 {
6775 /* The friend template has already been declared. Just
6776 check to see that the declarations match, and install any new
6777 default parameters. We must tsubst the default parameters,
6778 of course. We only need the innermost template parameters
6779 because that is all that redeclare_class_template will look
6780 at. */
6783 {
6784 tree parms;
6785 location_t saved_input_location;
6794 }
6797 }
6798 else
6799 {
6800 /* The friend template has not already been declared. In this
6801 case, the instantiation of the template class will cause the
6802 injection of this template into the global scope. */
6807 /* The new TMPL is not an instantiation of anything, so we
6808 forget its origins. We don't reset CLASSTYPE_TI_TEMPLATE for
6809 the new type because that is supposed to be the corresponding
6810 template decl, i.e., TMPL. */
6817 /* Inject this template into the global scope. */
6819 }
6822 {
6825 else
6827 }
6830 }
6832 /* Returns zero if TYPE cannot be completed later due to circularity.
6833 Otherwise returns one. */
6835 static int
6837 {
6847 else
6849 }
6851 /* Apply any attributes which had to be deferred until instantiation
6852 time. DECL_P, ATTRIBUTES and ATTR_FLAGS are as cplus_decl_attributes;
6853 ARGS, COMPLAIN, IN_DECL are as tsubst. */
6855 static void
6858 {
6860 tree t;
6865 {
6869 }
6872 {
6876 }
6877 else
6881 {
6886 {
6889 {
6892 /* If the first attribute argument is an identifier, don't
6893 pass it through tsubst. Attributes like mode, format,
6894 cleanup and several target specific attributes expect it
6895 unmodified. */
6901 {
6902 tree chain
6904 in_decl,
6909 chain);
6910 }
6911 else
6917 }
6918 else
6920 }
6923 }
6924 }
6926 tree
6928 {
6930 tree typedecl;
6931 tree pbinfo;
6932 tree base_list;
6942 /* Figure out which template is being instantiated. */
6946 /* Determine what specialization of the original template to
6947 instantiate. */
6950 {
6953 }
6955 {
6956 /* This TYPE is actually an instantiation of a partial
6957 specialization. We replace the innermost set of ARGS with
6958 the arguments appropriate for substitution. For example,
6959 given:
6961 template <class T> struct S {};
6962 template <class T> struct S<T*> {};
6964 and supposing that we are instantiating S<int*>, ARGS will
6965 presently be {int*} -- but we need {int}. */
6968 }
6969 else
6970 {
6973 }
6975 /* If the template we're instantiating is incomplete, then clearly
6976 there's nothing we can do. */
6980 /* If we've recursively instantiated too many templates, stop. */
6984 /* Now we're really doing the instantiation. Mark the type as in
6985 the process of being defined. */
6988 /* We may be in the middle of deferred access check. Disable
6989 it now. */
6996 /* Set the input location to the template definition. This is needed
6997 if tsubsting causes an error. */
7018 {
7021 }
7025 /* We should never instantiate a nested class before its enclosing
7026 class; we need to look up the nested class by name before we can
7027 instantiate it, and that lookup should instantiate the enclosing
7028 class. */
7035 {
7036 tree pbase_binfo;
7038 tree pushed_scope;
7041 /* We must enter the scope containing the type, as that is where
7042 the accessibility of types named in dependent bases are
7043 looked up from. */
7046 /* Substitute into each of the bases to determine the actual
7047 basetypes. */
7049 {
7050 tree base;
7056 {
7057 expanded_bases =
7064 }
7067 {
7069 /* Extract the already-expanded base class. */
7071 else
7072 /* Substitute to figure out the base class. */
7074 NULL_TREE);
7082 }
7083 }
7085 /* The list is now in reverse order; correct that. */
7090 }
7091 /* Now call xref_basetypes to set up all the base-class
7092 information. */
7099 /* Now that our base classes are set up, enter the scope of the
7100 class, so that name lookups into base classes, etc. will work
7101 correctly. This is precisely analogous to what we do in
7102 begin_class_definition when defining an ordinary non-template
7103 class, except we also need to push the enclosing classes. */
7106 /* Now members are processed in the order of declaration. */
7109 {
7113 {
7115 {
7116 /* Build new CLASSTYPE_NESTED_UTDS. */
7118 tree newtag;
7124 /* If the member is a class template, then -- even after
7125 substitution -- there may be dependent types in the
7126 template argument list for the class. We increment
7127 PROCESSING_TEMPLATE_DECL so that dependent_type_p, as
7128 that function will assume that no types are dependent
7129 when outside of a template. */
7139 {
7143 /* Unfortunately, lookup_template_class sets
7144 CLASSTYPE_IMPLICIT_INSTANTIATION for a partial
7145 instantiation (i.e., for the type of a member
7146 template class nested within a template class.)
7147 This behavior is required for
7148 maybe_process_partial_specialization to work
7149 correctly, but is not accurate in this case;
7150 the TAG is not an instantiation of anything.
7151 (The corresponding TEMPLATE_DECL is an
7152 instantiation, but the TYPE is not.) */
7155 /* Now, we call pushtag to put this NEWTAG into the scope of
7156 TYPE. We first set up the IDENTIFIER_TYPE_VALUE to avoid
7157 pushtag calling push_template_decl. We don't have to do
7158 this for enums because it will already have been done in
7159 tsubst_enum. */
7163 }
7164 }
7167 {
7168 /* Build new TYPE_METHODS. */
7169 tree r;
7178 }
7179 else
7180 {
7181 /* Build new TYPE_FIELDS. */
7183 {
7184 tree condition =
7192 }
7194 {
7195 tree r;
7197 /* The file and line for this declaration, to
7198 assist in error message reporting. Since we
7199 called push_tinst_level above, we don't need to
7200 restore these. */
7209 {
7210 /* In [temp.inst]:
7212 [t]he initialization (and any associated
7213 side-effects) of a static data member does
7214 not occur unless the static data member is
7215 itself used in a way that requires the
7216 definition of the static data member to
7217 exist.
7219 Therefore, we do not substitute into the
7220 initialized for the static data member here. */
7221 finish_static_data_member_decl
7229 }
7231 {
7232 /* Determine whether R has a valid type and can be
7233 completed later. If R is invalid, then it is
7234 replaced by error_mark_node so that it will not be
7235 added to TYPE_FIELDS. */
7241 {
7244 }
7245 }
7247 /* If it is a TYPE_DECL for a class-scoped ENUMERAL_TYPE,
7248 such a thing will already have been added to the field
7249 list by tsubst_enum in finish_member_declaration in the
7250 CLASSTYPE_NESTED_UTDS case above. */
7254 {
7257 }
7258 }
7259 }
7260 }
7261 else
7262 {
7264 {
7265 /* Build new CLASSTYPE_FRIEND_CLASSES. */
7271 {
7272 /* template <class T> friend class C; */
7275 }
7277 {
7278 /* template <class T> friend class C::D; */
7284 }
7286 {
7287 /* This could be either
7289 friend class T::C;
7291 when dependent_type_p is false or
7293 template <class U> friend class T::C;
7295 otherwise. */
7298 /* Bump processing_template_decl for correct
7299 dependent_type_p calculation. */
7304 }
7307 {
7308 /* friend class C;
7310 where C hasn't been declared yet. Let's lookup name
7311 from namespace scope directly, bypassing any name that
7312 come from dependent base class. */
7315 /* The call to xref_tag_from_type does injection for friend
7316 classes. */
7318 friend_type =
7322 }
7324 /* friend class C<T>; */
7327 /* Otherwise it's
7329 friend class C;
7331 where C is already declared or
7333 friend class C<int>;
7335 We don't have to do anything in these cases. */
7338 /* Trick make_friend_class into realizing that the friend
7339 we're adding is a template, not an ordinary class. It's
7340 important that we use make_friend_class since it will
7341 perform some error-checking and output cross-reference
7342 information. */
7350 }
7351 else
7352 {
7353 /* Build new DECL_FRIENDLIST. */
7354 tree r;
7356 /* The file and line for this declaration, to
7357 assist in error message reporting. Since we
7358 called push_tinst_level above, we don't need to
7359 restore these. */
7363 {
7366 }
7371 {
7374 }
7375 }
7376 }
7377 }
7379 /* Set the file and line number information to whatever is given for
7380 the class itself. This puts error messages involving generated
7381 implicit functions at a predictable point, and the same point
7382 that would be used for non-template classes. */
7389 /* Now that the class is complete, instantiate default arguments for
7390 any member functions. We don't do this earlier because the
7391 default arguments may reference members of the class. */
7395 /* Implicitly generated member functions will not have template
7396 information; they are not instantiations, but instead are
7397 created "fresh" for each instantiation. */
7406 /* The vtable for a template class can be emitted in any translation
7407 unit in which the class is instantiated. When there is no key
7408 method, however, finish_struct_1 will already have added TYPE to
7409 the keyed_classes list. */
7414 }
7416 static tree
7418 {
7419 tree r;
7425 else
7426 {
7430 }
7432 }
7434 /* Substitute ARGS into T, which is an pack expansion
7435 (i.e. TYPE_PACK_EXPANSION or EXPR_PACK_EXPANSION). Returns a
7436 TREE_VEC with the substituted arguments, a PACK_EXPANSION_* node
7437 (if only a partial substitution could be performed) or
7438 ERROR_MARK_NODE if there was an error. */
7439 tree
7441 tree in_decl)
7442 {
7443 tree pattern;
7446 tree result;
7452 /* Determine the argument packs that will instantiate the parameter
7453 packs used in the expansion expression. While we're at it,
7454 compute the number of arguments to be expanded and make sure it
7455 is consistent. */
7458 {
7465 else
7466 {
7473 }
7480 /* This can only happen if we forget to expand an argument
7481 pack somewhere else. Just return an error, silently. */
7482 {
7486 }
7491 {
7496 /* The argument pack that the parameter maps to is just an
7497 expansion of the parameter itself, such as one would
7498 find in the implicit typedef of a class inside the
7499 class itself. Consider this parameter "unsubstituted",
7500 so that we will maintain the outer pack expansion. */
7502 }
7505 {
7509 /* It's all-or-nothing with incomplete argument packs. */
7517 {
7520 }
7522 {
7526 pattern);
7527 else
7530 pattern);
7532 }
7534 /* Keep track of the parameter packs and their corresponding
7535 argument packs. */
7538 }
7539 else
7540 /* We can't substitute for this parameter pack. */
7543 unsubstituted_packs);
7544 }
7546 /* We cannot expand this expansion expression, because we don't have
7547 all of the argument packs we need. Substitute into the pattern
7548 and return a PACK_EXPANSION_*. The caller will need to deal with
7549 that. */
7552 in_decl));
7554 /* We could not find any argument packs that work. */
7558 /* For each argument in each argument pack, substitute into the
7559 pattern. */
7562 {
7563 /* For parameter pack, change the substitution of the parameter
7564 pack to the ith argument in its argument pack, then expand
7565 the pattern. */
7567 {
7571 {
7572 /* Select the Ith argument from the pack. */
7578 }
7579 else
7580 {
7586 {
7587 /* Select the Ith argument from the pack. */
7591 }
7593 /* Update the corresponding argument. */
7595 }
7596 }
7598 /* Substitute into the PATTERN with the altered arguments. */
7603 else
7607 /* When we have incomplete argument packs, the last "expanded"
7608 result is itself a pack expansion, which allows us
7609 to deduce more arguments. */
7614 {
7617 }
7618 }
7620 /* Update ARGS to restore the substitution from parameter packs to
7621 their argument packs. */
7623 {
7628 else
7629 {
7633 /* Update the corresponding argument. */
7637 else
7639 }
7640 }
7643 }
7645 /* Substitute ARGS into the vector or list of template arguments T. */
7647 static tree
7649 {
7656 {
7658 tree new_arg;
7663 {
7664 /* Substitute into an expansion expression. */
7668 /* Add to the expanded length adjustment the number of
7669 expanded arguments. We subtract one from this
7670 measurement, because the argument pack expression
7671 itself is already counted as 1 in
7672 LEN. EXPANDED_LEN_ADJUST can actually be negative, if
7673 the argument pack is empty. */
7675 }
7677 {
7678 /* Substitute into each of the arguments. */
7682 new_arg,
7696 }
7697 }
7698 else
7707 }
7712 /* Make space for the expanded arguments coming from template
7713 argument packs. */
7716 {
7720 {
7723 /* Now expand the template argument pack "in place". */
7726 }
7727 else
7728 {
7730 out++;
7731 }
7732 }
7735 }
7737 /* Return the result of substituting ARGS into the template parameters
7738 given by PARMS. If there are m levels of ARGS and m + n levels of
7739 PARMS, then the result will contain n levels of PARMS. For
7740 example, if PARMS is `template <class T> template <class U>
7741 template <T*, U, class V>' and ARGS is {{int}, {double}} then the
7742 result will be `template <int*, double, class V>'. */
7744 static tree
7746 {
7750 /* When substituting into a template, we must set
7751 PROCESSING_TEMPLATE_DECL as the template parameters may be
7752 dependent if they are based on one-another, and the dependency
7753 predicates are short-circuit outside of templates. */
7760 {
7761 tree new_vec =
7766 {
7767 tree tuple;
7768 tree default_value;
7769 tree parm_decl;
7791 }
7797 }
7802 }
7804 /* Substitute the ARGS into the indicated aggregate (or enumeration)
7805 type T. If T is not an aggregate or enumeration type, it is
7806 handled as if by tsubst. IN_DECL is as for tsubst. If
7807 ENTERING_SCOPE is nonzero, T is the context for a template which
7808 we are presently tsubst'ing. Return the substituted value. */
7810 static tree
7812 tree args,
7813 tsubst_flags_t complain,
7814 tree in_decl,
7816 {
7821 {
7826 /* Else fall through. */
7830 {
7831 tree argvec;
7832 tree context;
7833 tree r;
7836 /* In "sizeof(X<I>)" we need to evaluate "I". */
7840 /* First, determine the context for the type we are looking
7841 up. */
7844 {
7847 /* If context is a nested class inside a class template,
7848 it may still need to be instantiated (c++/33959). */
7851 }
7853 /* Then, figure out what arguments are appropriate for the
7854 type we are trying to find. For example, given:
7856 template <class T> struct S;
7857 template <class T, class U> void f(T, U) { S<U> su; }
7859 and supposing that we are instantiating f<int, double>,
7860 then our ARGS will be {int, double}, but, when looking up
7861 S we only want {double}. */
7866 else
7867 {
7871 }
7876 }
7877 else
7878 /* This is not a template type, so there's nothing to do. */
7883 }
7884 }
7886 /* Substitute into the default argument ARG (a default argument for
7887 FN), which has the indicated TYPE. */
7889 tree
7891 {
7895 /* This default argument came from a template. Instantiate the
7896 default argument here, not in tsubst. In the case of
7897 something like:
7899 template <class T>
7900 struct S {
7901 static T t();
7902 void f(T = t());
7903 };
7905 we must be careful to do name lookup in the scope of S<T>,
7906 rather than in the current class. */
7908 /* The "this" pointer is not valid in a default argument. */
7910 {
7915 }
7918 /* The default argument expression may cause implicitly defined
7919 member functions to be synthesized, which will result in garbage
7920 collection. We must treat this situation as if we were within
7921 the body of function so as to avoid collecting live data on the
7922 stack. */
7930 /* Restore the "this" pointer. */
7932 {
7935 }
7939 /* Make sure the default argument is reasonable. */
7943 }
7945 /* Substitute into all the default arguments for FN. */
7947 static void
7949 {
7950 tree arg;
7951 tree tmpl_args;
7955 /* If this function is not yet instantiated, we certainly don't need
7956 its default arguments. */
7961 arg;
7967 }
7969 /* Substitute the ARGS into the T, which is a _DECL. Return the
7970 result of the substitution. Issue error and warning messages under
7971 control of COMPLAIN. */
7973 static tree
7975 {
7976 location_t saved_loc;
7980 /* Set the filename and linenumber to improve error-reporting. */
7985 {
7987 {
7988 /* We can get here when processing a member function template,
7989 member class template, and template template parameter of
7990 a template class. */
7992 tree spec;
7993 tree tmpl_args;
7994 tree full_args;
7997 {
7998 /* Template template parameter is treated here. */
8010 complain);
8013 }
8015 /* We might already have an instance of this template.
8016 The ARGS are for the surrounding class type, so the
8017 full args contain the tsubst'd args for the context,
8018 plus the innermost args from the template decl. */
8022 /* Because this is a template, the arguments will still be
8023 dependent, even after substitution. If
8024 PROCESSING_TEMPLATE_DECL is not set, the dependency
8025 predicates will short-circuit. */
8033 /* tsubst_template_args doesn't copy the vector if
8034 nothing changed. But, *something* should have
8035 changed. */
8041 {
8044 }
8046 /* Make a new template decl. It will be similar to the
8047 original, but will record the current template arguments.
8048 We also create a new function declaration, which is just
8049 like the old one, but points to this new template, rather
8050 than the old one. */
8058 {
8059 tree new_type;
8071 }
8072 else
8073 {
8074 tree new_decl;
8086 }
8092 /* The template parameters for this new template are all the
8093 template parameters for the old template, except the
8094 outermost level of parameters. */
8097 complain);
8103 /* Record this non-type partial instantiation. */
8107 }
8111 {
8112 tree ctx;
8115 tree gen_tmpl;
8116 tree type;
8121 /* Nobody should be tsubst'ing into non-template functions. */
8125 {
8126 tree spec;
8129 /* If T is not dependent, just return it. We have to
8130 increment PROCESSING_TEMPLATE_DECL because
8131 value_dependent_expression_p assumes that nothing is
8132 dependent when PROCESSING_TEMPLATE_DECL is zero. */
8139 /* Calculate the most general template of which R is a
8140 specialization, and the complete set of arguments used to
8141 specialize R. */
8147 /* Check to see if we already have this specialization. */
8152 {
8155 }
8157 /* We can see more levels of arguments than parameters if
8158 there was a specialization of a member template, like
8159 this:
8161 template <class T> struct S { template <class U> void f(); }
8162 template <> template <class U> void S<int>::f(U);
8164 Here, we'll be substituting into the specialization,
8165 because that's where we can find the code we actually
8166 want to generate, but we'll have enough arguments for
8167 the most general template.
8169 We also deal with the peculiar case:
8171 template <class T> struct S {
8172 template <class U> friend void f();
8173 };
8174 template <class U> void f() {}
8175 template S<int>;
8176 template void f<double>();
8178 Here, the ARGS for the instantiation of will be {int,
8179 double}. But, we only need as many ARGS as there are
8180 levels of template parameters in CODE_PATTERN. We are
8181 careful not to get fooled into reducing the ARGS in
8182 situations like:
8184 template <class T> struct S { template <class U> void f(U); }
8185 template <class T> template <> void S<T>::f(int) {}
8187 which we can spot because the pattern will be a
8188 specialization in this case. */
8190 parms_depth =
8195 }
8196 else
8197 {
8198 /* This special case arises when we have something like this:
8200 template <class T> struct S {
8201 friend void f<int>(int, double);
8202 };
8204 Here, the DECL_TI_TEMPLATE for the friend declaration
8205 will be an IDENTIFIER_NODE. We are being called from
8206 tsubst_friend_function, and we want only to create a
8207 new decl (R) with appropriate types so that we can call
8208 determine_specialization. */
8210 }
8213 {
8216 else
8220 }
8221 else
8222 {
8225 }
8230 /* We do NOT check for matching decls pushed separately at this
8231 point, as they may not represent instantiations of this
8232 template, and in any case are considered separate under the
8233 discrete model. */
8237 /* Clear out the mangled name and RTL for the instantiation. */
8240 /* Leave DECL_INITIAL set on deleted instantiations. */
8246 /* Type-conversion operator. Reconstruct the name, in
8247 case it's the name of one of the template's parameters. */
8257 /* If this is an instantiation of a function with internal
8258 linkage, we already know what object file linkage will be
8259 assigned to the instantiation. */
8269 {
8274 }
8276 /* Set up the DECL_TEMPLATE_INFO for R. There's no need to do
8277 this in the special friend case mentioned above where
8278 GEN_TMPL is NULL. */
8280 {
8286 /* We're not supposed to instantiate default arguments
8287 until they are called, for a template. But, for a
8288 declaration like:
8290 template <class T> void f ()
8291 { extern void g(int i = T()); }
8293 we should do the substitution when the template is
8294 instantiated. We handle the member function case in
8295 instantiate_class_template since the default arguments
8296 might refer to other members of the class. */
8301 }
8302 else
8305 /* Copy the list of befriending classes. */
8309 {
8313 in_decl);
8314 }
8317 {
8321 /* If this is an instantiation of a member template, clone it.
8322 If it isn't, that'll be handled by
8323 clone_constructors_and_destructors. */
8326 }
8336 /* Possibly limit visibility based on template args. */
8339 {
8343 }
8348 }
8352 {
8360 {
8361 /* If there is a local specialization that isn't a
8362 parameter pack, it means that we're doing a "simple"
8363 substitution from inside tsubst_pack_expansion. Just
8364 return the local specialization (which will be a single
8365 parm). */
8372 /* Expand the TYPE_PACK_EXPANSION that provides the types for
8373 the parameters in this function parameter pack. */
8377 {
8380 /* Zero-length parameter packs are boring. Just substitute
8381 into the chain. */
8385 }
8386 else
8387 {
8388 /* All we did was update the type. Make a note of that. */
8391 }
8392 }
8394 /* Loop through all of the parameter's we'll build. When T is
8395 a function parameter pack, LEN is the number of expanded
8396 types in EXPANDED_TYPES; otherwise, LEN is 1. */
8399 {
8406 /* We're on the Ith parameter of the function parameter
8407 pack. */
8408 {
8409 /* Get the Ith type. */
8413 /* Rename the parameter to include the index. */
8416 }
8418 /* We're dealing with a normal parameter. */
8426 {
8429 else
8432 }
8442 /* Keep track of the first new parameter we
8443 generate. That's what will be returned to the
8444 caller. */
8448 /* Build a proper chain of parameters when substituting
8449 into a function parameter pack. */
8452 }
8458 /* FIRST_R contains the start of the chain we've built. */
8460 }
8464 {
8465 tree type;
8474 /* DECL_INITIAL gives the number of bits in a bit-field. */
8479 /* We don't have to set DECL_CONTEXT here; it is set by
8480 finish_member_declaration. */
8487 }
8491 /* We reach here only for member using decls. */
8493 {
8494 r = do_class_using_decl
8499 else
8500 {
8503 }
8504 }
8505 else
8506 {
8509 }
8514 {
8517 tree spec;
8519 tree ctx;
8525 {
8526 /* If this is the canonical decl, we don't have to
8527 mess with instantiations, and often we can't (for
8528 typename, template type parms and such). Note that
8529 TYPE_NAME is not correct for the above test if
8530 we've copied the type for a typedef. */
8536 }
8538 /* Check to see if we already have the specialization we
8539 need. */
8542 {
8543 /* T is a static data member or namespace-scope entity.
8544 We have to substitute into namespace-scope variables
8545 (even though such entities are never templates) because
8546 of cases like:
8548 template <class T> void f() { extern T t; }
8550 where the entity referenced is not known until
8551 instantiation time. */
8555 {
8557 complain,
8559 /* If CTX is unchanged, then T is in fact the
8560 specialization we want. That situation occurs when
8561 referencing a static data member within in its own
8562 class. We can use pointer equality, rather than
8563 same_type_p, because DECL_CONTEXT is always
8564 canonical. */
8567 }
8570 {
8574 spec = (retrieve_specialization
8577 }
8578 }
8579 else
8580 {
8581 /* A local variable. */
8583 /* Subsequent calls to pushdecl will fill this in. */
8586 }
8587 /* If we already have the specialization we need, there is
8588 nothing more to do. */
8590 {
8593 }
8595 /* Create a new node for the specialization we need. */
8600 {
8601 /* Even if the original location is out of scope, the
8602 newly substituted one is not. */
8609 {
8610 /* It may seem that this case cannot occur, since:
8612 typedef void f();
8613 void g() { f x; }
8615 declares a function, not a variable. However:
8617 typedef void f();
8618 template <typename T> void g() { T t; }
8619 template void g<f>();
8621 is an attempt to declare a variable with function
8622 type. */
8624 /* R is not yet sufficiently initialized, so we
8625 just use its name. */
8628 }
8635 {
8640 }
8641 }
8647 /* Clear out the mangled name and RTL for the instantiation. */
8651 /* The initializer must not be expanded until it is required;
8652 see [temp.inst]. */
8658 {
8659 /* Possibly limit visibility based on template args. */
8662 {
8666 }
8668 }
8669 /* Preserve a typedef that names a type. */
8673 {
8678 }
8681 {
8682 /* A static data member declaration is always marked
8683 external when it is declared in-class, even if an
8684 initializer is present. We mimic the non-template
8685 processing here. */
8691 }
8692 else
8701 }
8706 }
8708 /* Restore the file and line information. */
8712 }
8714 /* Substitute into the ARG_TYPES of a function type. */
8716 static tree
8718 tree args,
8719 tsubst_flags_t complain,
8720 tree in_decl)
8721 {
8722 tree remaining_arg_types;
8726 tree default_arg;
8737 {
8738 /* For a pack expansion, perform substitution on the
8739 entire expression. Later on, we'll handle the arguments
8740 one-by-one. */
8745 /* So that we'll spin through the parameters, one by one. */
8747 else
8748 {
8749 /* We only partially substituted into the parameter
8750 pack. Our type is TYPE_PACK_EXPANSION. */
8753 }
8754 }
8767 {
8769 {
8773 }
8775 }
8777 /* Do array-to-pointer, function-to-pointer conversion, and ignore
8778 top-level qualifiers as required. */
8781 /* We do not substitute into default arguments here. The standard
8782 mandates that they be instantiated only when needed, which is
8783 done in build_over_call. */
8787 {
8788 /* We've instantiated a template before its default arguments
8789 have been parsed. This can happen for a nested template
8790 class, and is not an error unless we require the default
8791 argument in a call of this function. */
8792 remaining_arg_types =
8795 remaining_arg_types);
8796 }
8797 else
8798 remaining_arg_types =
8800 }
8803 }
8805 /* Substitute into a FUNCTION_TYPE or METHOD_TYPE. This routine does
8806 *not* handle the exception-specification for FNTYPE, because the
8807 initial substitution of explicitly provided template parameters
8808 during argument deduction forbids substitution into the
8809 exception-specification:
8811 [temp.deduct]
8813 All references in the function type of the function template to the
8814 corresponding template parameters are replaced by the specified tem-
8815 plate argument values. If a substitution in a template parameter or
8816 in the function type of the function template results in an invalid
8817 type, type deduction fails. [Note: The equivalent substitution in
8818 exception specifications is done only when the function is instanti-
8819 ated, at which point a program is ill-formed if the substitution
8820 results in an invalid type.] */
8822 static tree
8824 tree args,
8825 tsubst_flags_t complain,
8826 tree in_decl)
8827 {
8828 tree return_type;
8829 tree arg_types;
8830 tree fntype;
8832 /* The TYPE_CONTEXT is not used for function/method types. */
8835 /* Substitute the return type. */
8839 /* The standard does not presently indicate that creation of a
8840 function type with an invalid return type is a deduction failure.
8841 However, that is clearly analogous to creating an array of "void"
8842 or a reference to a reference. This is core issue #486. */
8845 {
8847 {
8850 else
8852 }
8854 }
8856 /* Substitute the argument types. */
8862 /* Construct a new type node and return it. */
8865 else
8866 {
8869 {
8870 /* [temp.deduct]
8872 Type deduction may fail for any of the following
8873 reasons:
8875 -- Attempting to create "pointer to member of T" when T
8876 is not a class type. */
8879 r);
8881 }
8885 }
8890 }
8892 /* FNTYPE is a FUNCTION_TYPE or METHOD_TYPE. Substitute the template
8893 ARGS into that specification, and return the substituted
8894 specification. If there is no specification, return NULL_TREE. */
8896 static tree
8898 tree args,
8899 tsubst_flags_t complain,
8900 tree in_decl)
8901 {
8902 tree specs;
8903 tree new_specs;
8908 {
8911 else
8913 {
8914 tree spec;
8919 {
8920 /* Expand the pack expansion type. */
8923 in_decl);
8929 else
8930 {
8931 /* We're substituting into a member template, so
8932 we got a TYPE_PACK_EXPANSION back. Add that
8933 expansion and move on. */
8937 expanded_specs,
8938 complain);
8941 }
8942 }
8945 {
8948 else
8953 complain);
8954 }
8957 }
8958 }
8960 }
8962 /* Take the tree structure T and replace template parameters used
8963 therein with the argument vector ARGS. IN_DECL is an associated
8964 decl for diagnostics. If an error occurs, returns ERROR_MARK_NODE.
8965 Issue error and warning messages under control of COMPLAIN. Note
8966 that we must be relatively non-tolerant of extensions here, in
8967 order to preserve conformance; if we allow substitutions that
8968 should not be allowed, we may allow argument deductions that should
8969 not succeed, and therefore report ambiguous overload situations
8970 where there are none. In theory, we could allow the substitution,
8971 but indicate that it should have failed, and allow our caller to
8972 make sure that the right thing happens, but we don't try to do this
8973 yet.
8975 This function is used for dealing with types, decls and the like;
8976 for expressions, use tsubst_expr or tsubst_copy. */
8978 static tree
8980 {
8999 else
9004 /* Reuse typedefs. We need to do this to handle dependent attributes,
9005 such as attribute aligned. */
9009 {
9015 {
9019 }
9024 else
9025 /* The typedef is from a non-template context. */
9029 {
9031 r = cp_build_qualified_type_real
9035 }
9036 /* Else we must be instantiating the typedef, so fall through. */
9037 }
9049 {
9076 {
9086 {
9090 }
9092 /* [temp.deduct]
9094 Type deduction may fail for any of the following
9095 reasons:
9097 Attempting to create an array with a size that is
9098 zero or negative. */
9100 /* We must fail if performing argument deduction (as
9101 indicated by the state of complain), so that
9102 another substitution can be found. */
9106 {
9111 }
9114 }
9120 {
9133 {
9137 /* See through ARGUMENT_PACK_SELECT arguments. */
9139 }
9144 {
9146 /* If ARG is an argument pack, we don't actually want to
9147 perform a substitution here, because substitutions
9148 for argument packs are only done
9149 element-by-element. We can get to this point when
9150 substituting the type of a non-type template
9151 parameter pack, when that type actually contains
9152 template parameter packs from an outer template, e.g.,
9154 template<typename... Types> struct A {
9155 template<Types... Values> struct B { };
9156 }; */
9160 {
9164 /* cv-quals from the template are discarded when
9165 substituting in a function or reference type. */
9170 else
9173 return cp_build_qualified_type_real
9175 }
9177 {
9178 /* We are processing a type constructed from a
9179 template template parameter. */
9185 /* We can get a TEMPLATE_TEMPLATE_PARM here when we
9186 are resolving nested-types in the signature of a
9187 member function templates. Otherwise ARG is a
9188 TEMPLATE_DECL and is the real template to be
9189 instantiated. */
9197 complain);
9198 return cp_build_qualified_type_real
9200 }
9201 else
9202 /* TEMPLATE_TEMPLATE_PARM or TEMPLATE_PARM_INDEX. */
9204 }
9207 /* This can happen during the attempted tsubst'ing in
9208 unify. This means that we don't yet have any information
9209 about the template parameter in question. */
9212 /* If we get here, we must have been looking at a parm for a
9213 more deeply nested template. Make a new version of this
9214 template parameter, but with a lower level. */
9216 {
9221 {
9223 r = cp_build_qualified_type_real
9227 }
9228 else
9229 {
9240 /* We have reduced the level of the template
9241 template parameter, but not the levels of its
9242 template parameters, so canonical_type_parameter
9243 will not be able to find the canonical template
9244 template parameter for this level. Thus, we
9245 require structural equality checking to compare
9246 TEMPLATE_TEMPLATE_PARMs. */
9250 else
9254 {
9262 }
9263 }
9272 }
9275 }
9278 {
9286 {
9290 }
9293 {
9297 }
9300 {
9304 }
9310 }
9313 /* We should never be tsubsting a binfo. */
9317 /* A vector of template arguments. */
9323 {
9332 /* [temp.deduct]
9334 Type deduction may fail for any of the following
9335 reasons:
9337 -- Attempting to create a pointer to reference type.
9338 -- Attempting to create a reference to a reference type or
9339 a reference to void.
9341 Core issue 106 says that creating a reference to a reference
9342 during instantiation is no longer a cause for failure. We
9343 only enforce this check in strict C++98 mode. */
9347 {
9350 /* We keep track of the last time we issued this error
9351 message to avoid spewing a ton of messages during a
9352 single bad template instantiation. */
9355 {
9358 else
9361 type);
9363 }
9366 }
9368 {
9372 }
9374 /* In C++0x, during template argument substitution, when there is an
9375 attempt to create a reference to a reference type, reference
9376 collapsing is applied as described in [14.3.1/4 temp.arg.type]:
9378 "If a template-argument for a template-parameter T names a type
9379 that is a reference to a type A, an attempt to create the type
9380 'lvalue reference to cv T' creates the type 'lvalue reference to
9381 A,' while an attempt to create the type type rvalue reference to
9382 cv T' creates the type T"
9383 */
9384 r = cp_build_reference_type
9387 else
9392 /* Will this ever be needed for TYPE_..._TO values? */
9396 }
9398 {
9401 {
9402 /* [temp.deduct]
9404 Type deduction may fail for any of the following
9405 reasons:
9407 -- Attempting to create "pointer to member of T" when T
9408 is not a class type. */
9412 }
9414 {
9418 }
9420 {
9424 }
9427 {
9428 /* The type of the implicit object parameter gets its
9429 cv-qualifiers from the FUNCTION_TYPE. */
9430 tree method_type;
9433 tree memptr;
9439 complain);
9440 }
9441 else
9444 complain);
9445 }
9448 {
9449 tree fntype;
9450 tree specs;
9455 /* Substitute the exception specification. */
9457 in_decl);
9463 }
9465 {
9470 /* As an optimization, we avoid regenerating the array type if
9471 it will obviously be the same as T. */
9475 /* These checks should match the ones in grokdeclarator.
9477 [temp.deduct]
9479 The deduction may fail for any of the following reasons:
9481 -- Attempting to create an array with an element type that
9482 is void, a function type, or a reference type, or [DR337]
9483 an abstract class type. */
9487 {
9491 }
9493 {
9496 type);
9498 }
9503 {
9506 }
9509 }
9513 {
9521 }
9525 {
9531 }
9534 {
9544 {
9548 }
9550 {
9551 /* Normally, make_typename_type does not require that the CTX
9552 have complete type in order to allow things like:
9554 template <class T> struct S { typename S<T>::X Y; };
9556 But, such constructs have already been resolved by this
9557 point, so here CTX really should have complete type, unless
9558 it's a partial instantiation. */
9561 {
9565 }
9566 }
9573 {
9576 }
9579 {
9586 }
9588 return cp_build_qualified_type_real
9590 }
9593 {
9605 }
9613 {
9621 }
9624 {
9632 }
9635 {
9636 tree type;
9645 complain);
9646 }
9649 {
9650 tree type;
9660 type =
9666 complain);
9667 }
9671 {
9673 tree packed_out =
9675 args,
9676 complain,
9677 in_decl);
9680 /* For template nontype argument packs, also substitute into
9681 the type. */
9686 }
9693 }
9694 }
9696 /* Like tsubst_expr for a BASELINK. OBJECT_TYPE, if non-NULL, is the
9697 type of the expression on the left-hand side of the "." or "->"
9698 operator. */
9700 static tree
9703 {
9704 tree name;
9705 tree qualifying_scope;
9706 tree fns;
9707 tree optype;
9711 /* A baselink indicates a function from a base class. Both the
9712 BASELINK_ACCESS_BINFO and the base class referenced may
9713 indicate bases of the template class, rather than the
9714 instantiated class. In addition, lookups that were not
9715 ambiguous before may be ambiguous now. Therefore, we perform
9716 the lookup again. */
9723 {
9730 }
9734 /* If lookup found a single function, mark it as used at this
9735 point. (If it lookup found multiple functions the one selected
9736 later by overload resolution will be marked as used at that
9737 point.) */
9743 /* Add back the template arguments, if present. */
9748 template_args);
9749 /* Update the conversion operator type. */
9756 qualifying_scope,
9757 object_type);
9758 }
9760 /* Like tsubst_expr for a SCOPE_REF, given by QUALIFIED_ID. DONE is
9761 true if the qualified-id will be a postfix-expression in-and-of
9762 itself; false if more of the postfix-expression follows the
9763 QUALIFIED_ID. ADDRESS_P is true if the qualified-id is the operand
9764 of "&". */
9766 static tree
9770 {
9771 tree expr;
9772 tree scope;
9773 tree name;
9775 tree template_args;
9779 /* Figure out what name to look up. */
9782 {
9789 }
9790 else
9791 {
9794 }
9796 /* Substitute into the qualifying scope. When there are no ARGS, we
9797 are just trying to simplify a non-dependent expression. In that
9798 case the qualifying scope may be dependent, and, in any case,
9799 substituting will not help. */
9802 {
9805 }
9806 else
9815 {
9817 /* If this were actually a destructor call, it would have been
9818 parsed as such by the parser. */
9820 else
9824 {
9826 {
9830 }
9832 }
9833 }
9836 {
9838 scope);
9839 /* Remember that there was a reference to this entity. */
9841 }
9844 {
9850 }
9859 {
9860 expr = (adjust_result_of_qualified_name_lookup
9862 expr = (finish_qualified_id_expr
9866 }
9868 /* Expressions do not generally have reference type. */
9870 /* However, if we're about to form a pointer-to-member, we just
9871 want the referenced member referenced. */
9876 }
9878 /* Like tsubst, but deals with expressions. This function just replaces
9879 template parms; to finish processing the resultant expression, use
9880 tsubst_expr. */
9882 static tree
9884 {
9886 tree r;
9894 {
9899 {
9900 /* This can happen for a parameter name used later in a function
9901 declaration (such as in a late-specified return type).
9902 Replace it with an arbitrary expression with the same type
9903 (*(T*)0). This should only occur in an unevaluated context
9904 (i.e. decltype). */
9911 }
9919 {
9920 tree enum_type;
9921 tree v;
9925 /* There is no need to substitute into namespace-scope
9926 enumerators. */
9929 /* If ARGS is NULL, then T is known to be non-dependent. */
9933 /* Unfortunately, we cannot just call lookup_name here.
9934 Consider:
9936 template <int I> int f() {
9937 enum E { a = I };
9938 struct S { void g() { E e = a; } };
9939 };
9941 When we instantiate f<7>::S::g(), say, lookup_name is not
9942 clever enough to find f<7>::a. */
9943 enum_type
9953 /* We didn't find the name. That should never happen; if
9954 name-lookup found it during preliminary parsing, we
9955 should find it again here during instantiation. */
9957 }
9962 {
9963 tree ctx;
9968 {
9971 {
9975 }
9977 }
9978 }
10001 {
10002 /* Template template argument like the following example need
10003 special treatment:
10005 template <template <class> class TT> struct C {};
10006 template <class T> struct D {
10007 template <class U> struct E {};
10008 C<E> c; // #1
10009 };
10010 D<int> d; // #2
10012 We are processing the template argument `E' in #1 for
10013 the template instantiation #2. Originally, `E' is a
10014 TEMPLATE_DECL with `D<T>' as its DECL_CONTEXT. Now we
10015 have to substitute this with one having context `D<int>'. */
10019 }
10020 else
10021 /* Ordinary template template argument. */
10030 return build1
10036 {
10037 /* We only want to compute the number of arguments. */
10051 {
10058 else
10061 }
10062 else
10064 }
10065 /* Fall through */
10079 return build1
10084 {
10085 tree object;
10086 tree name;
10091 {
10095 }
10098 {
10108 }
10113 in_decl);
10114 else
10117 }
10155 return build_nt
10168 return build_nt
10175 {
10183 }
10188 {
10189 r = build_nt
10195 }
10198 {
10199 r = build_nt
10205 }
10208 {
10209 r = build_nt
10215 }
10218 {
10219 /* Substituted template arguments */
10228 }
10231 {
10251 }
10276 {
10279 }
10280 else
10284 /* This is handled by tsubst_copy_and_build. */
10289 in_decl),
10293 /* We shouldn't have built any of these during initial template
10294 generation. Instead, they should be built during instantiation
10295 in response to the saved STMT_IS_FULL_EXPR_P setting. */
10312 }
10313 }
10315 /* Like tsubst_copy, but specifically for OpenMP clauses. */
10317 static tree
10319 tree in_decl)
10320 {
10324 {
10330 {
10333 {
10339 }
10340 /* FALLTHRU */
10362 }
10363 }
10366 }
10368 /* Like tsubst_copy_and_build, but unshare TREE_LIST nodes. */
10370 static tree
10372 tree in_decl)
10373 {
10374 #define RECUR(t) tsubst_copy_asm_operands (t, args, complain, in_decl)
10399 #undef RECUR
10400 }
10402 /* Substitute one OMP_FOR iterator. */
10404 static void
10409 {
10410 #define RECUR(NODE) \
10411 tsubst_expr ((NODE), args, complain, in_decl, \
10412 integral_constant_expression_p)
10421 {
10428 }
10432 {
10438 complain);
10439 else
10446 }
10449 {
10450 tree c;
10452 {
10463 }
10465 {
10470 {
10473 }
10474 }
10475 }
10481 else
10485 {
10496 {
10503 }
10504 else
10510 {
10516 }
10520 {
10527 }
10528 else
10534 }
10540 #undef RECUR
10541 }
10543 /* Like tsubst_copy for expressions, etc. but also does semantic
10544 processing. */
10546 static tree
10549 {
10550 #define RECUR(NODE) \
10551 tsubst_expr ((NODE), args, complain, in_decl, \
10552 integral_constant_expression_p)
10565 {
10567 {
10568 tree_stmt_iterator i;
10572 }
10587 else
10596 {
10597 tree decl;
10598 tree init;
10604 {
10607 tree decl;
10615 else
10617 }
10618 else
10619 {
10623 {
10624 /* By marking the declaration as instantiated, we avoid
10625 trying to instantiate it. Since instantiate_decl can't
10626 handle local variables, and since we've already done
10627 all that needs to be done, that's the right thing to
10628 do. */
10633 /* Anonymous aggregates are a special case. */
10635 else
10636 {
10640 {
10641 /* For __PRETTY_FUNCTION__ we have to adjust the
10642 initializer. */
10646 }
10647 else
10648 {
10652 /* If we had an initializer but it
10653 instantiated to nothing,
10654 value-initialize the object. This will
10655 only occur when the initializer was a
10656 pack expansion where the parameter packs
10657 used in that expansion were of length
10658 zero. */
10660 else
10662 }
10665 }
10666 }
10667 }
10669 /* A DECL_EXPR can also be used as an expression, in the condition
10670 clause of an if/for/while construct. */
10672 }
10710 {
10714 }
10722 else
10730 else
10762 /* Computed goto's must be tsubst'd into. On the other hand,
10763 non-computed gotos must not be; the identifier in question
10764 will have no binding. */
10766 else
10772 tmp = finish_asm_stmt
10778 {
10783 }
10788 {
10793 }
10794 else
10795 {
10800 else
10807 else
10813 else
10815 }
10819 {
10823 {
10825 /* Prevent instantiate_decl from trying to instantiate
10826 this variable. We've already done all that needs to be
10827 done. */
10830 }
10835 }
10843 {
10844 tree condition =
10846 args,
10853 }
10874 {
10889 integral_constant_expression_p);
10898 {
10902 }
10903 else
10904 {
10912 }
10926 }
10957 {
10962 }
10978 integral_constant_expression_p);
10979 }
10982 #undef RECUR
10983 }
10985 /* T is a postfix-expression that is not being used in a function
10986 call. Return the substituted version of T. */
10988 static tree
10990 tsubst_flags_t complain,
10991 tree in_decl)
10992 {
10996 else
11002 }
11004 /* Like tsubst but deals with expressions and performs semantic
11005 analysis. FUNCTION_P is true if T is the "F" in "F (ARGS)". */
11007 tree
11009 tree args,
11010 tsubst_flags_t complain,
11011 tree in_decl,
11014 {
11015 #define RECUR(NODE) \
11016 tsubst_copy_and_build (NODE, args, complain, in_decl, \
11018 integral_constant_expression_p)
11020 tree op1;
11026 {
11029 /* Fall through. */
11031 {
11032 tree decl;
11033 cp_id_kind idk;
11038 {
11041 }
11043 /* Look up the name. */
11046 /* By convention, expressions use ERROR_MARK_NODE to indicate
11047 failure, not NULL_TREE. */
11053 integral_constant_expression_p,
11061 input_location);
11067 }
11070 {
11071 tree object;
11079 {
11082 }
11083 else
11090 else
11092 }
11095 {
11099 {
11100 /* A type conversion to reference type will be enclosed in
11101 such an indirect ref, but the substitution of the cast
11102 will have also added such an indirect ref. */
11105 }
11106 else
11109 }
11112 return build_nop
11121 {
11122 tree type;
11123 tree op;
11128 {
11133 }
11138 {
11151 }
11152 }
11170 complain);
11177 else
11179 in_decl);
11216 return build_x_binary_op
11220 ? ERROR_MARK
11224 ? ERROR_MARK
11227 complain);
11240 /* Fall through */
11245 {
11246 /* When there are no ARGS, we are trying to evaluate a
11247 non-dependent expression from the parser. Trying to do
11248 the substitutions may not work. */
11251 }
11252 else
11253 {
11259 }
11263 else
11268 {
11269 tree r = build_x_modify_expr
11273 complain);
11274 /* TREE_NO_WARNING must be set if either the expression was
11275 parenthesized or it uses an operator such as >>= rather
11276 than plain assignment. In the former case, it was already
11277 set and must be copied. In the latter case,
11278 build_x_modify_expr sets it and it must not be reset
11279 here. */
11283 }
11288 /* Remember that there was a reference to this entity. */
11294 {
11298 /* If there was an initializer in the original tree, but
11299 it instantiated to an empty list, then we should pass on
11300 VOID_ZERO_NODE to tell build_new that it was an empty
11301 initializer () rather than no initializer. This can only
11302 happen when the initializer is a pack expansion whose
11303 parameter packs are of length zero. */
11306 return build_new
11310 init,
11312 complain);
11313 }
11316 return delete_sanity
11325 complain);
11328 {
11329 tree function;
11330 tree call_args;
11335 /* When we parsed the expression, we determined whether or
11336 not Koenig lookup should be performed. */
11339 {
11344 }
11345 else
11346 {
11348 {
11354 }
11355 else
11359 in_decl,
11361 integral_constant_expression_p);
11365 }
11367 /* FIXME: Rewrite this so as not to construct an arglist. */
11370 /* We do not perform argument-dependent lookup if normal
11371 lookup finds a non-function, in accordance with the
11372 expected resolution of DR 218. */
11375 /* If lookup found a member function, the Koenig lookup is
11376 not appropriate, even if an unqualified-name was used
11377 to denote the function. */
11383 {
11386 }
11388 /* Remember that there was a reference to this entity. */
11395 {
11400 complain);
11401 else
11408 complain));
11409 }
11410 /* Pass -1 for koenig_p so that build_new_function_call will
11411 allow hidden friends found by arg-dependent lookup at template
11412 parsing time. */
11416 complain);
11417 }
11420 return build_x_conditional_expr
11424 complain);
11427 return finish_pseudo_destructor_expr
11433 {
11441 {
11442 /* We have pack expansions, so expand those and
11443 create a new list out of it. */
11446 tree chain;
11449 /* Expand the argument expressions. */
11457 /* Build the rest of the list. */
11462 /* Determine the number of arguments. */
11464 {
11467 }
11470 else
11471 {
11472 /* Since we only performed a partial substitution into
11473 the argument pack, we only return a single list
11474 node. */
11481 }
11483 /* Convert the argument vectors into a TREE_LIST */
11486 {
11487 /* Grab the Ith values. */
11488 i--;
11491 value
11495 /* Build the list (backwards). */
11497 }
11500 }
11516 }
11519 {
11520 tree object;
11521 tree object_type;
11522 tree member;
11526 /* Remember that there was a reference to this entity. */
11536 else
11542 {
11544 {
11549 {
11552 }
11554 {
11558 }
11559 }
11560 }
11563 {
11564 tree tmpl;
11565 tree args;
11567 /* Lookup the template functions now that we know what the
11568 scope is. */
11575 {
11578 args);
11579 member = (adjust_result_of_qualified_name_lookup
11581 object_type));
11582 }
11583 else
11584 {
11586 input_location);
11588 }
11589 }
11593 {
11595 {
11599 else
11602 }
11604 }
11610 complain);
11611 }
11614 return build_throw
11618 {
11626 tree r;
11631 /* digest_init will do the wrong thing if we let it. */
11635 /* We do not want to process the index of aggregate
11636 initializers as they are identifier nodes which will be
11637 looked up by digest_init. */
11643 {
11648 {
11649 /* Substitute into the pack expansion. */
11651 in_decl);
11654 ;
11656 /* Just move the argument into place. */
11658 else
11659 {
11660 /* Update the length of the final CONSTRUCTOR
11661 arguments vector, and note that we will need to
11662 copy.*/
11665 }
11666 }
11667 else
11669 }
11672 {
11677 idx++)
11678 {
11680 {
11685 }
11686 else
11688 }
11689 }
11698 }
11701 {
11706 }
11711 /* Fall through */
11714 {
11718 /* If the original type was a reference, we'll be wrapped in
11719 the appropriate INDIRECT_REF. */
11722 }
11727 in_decl));
11733 {
11742 }
11745 {
11751 integral_constant_expression_p);
11756 }
11760 /* As in finish_id_expression, we resolve enumeration constants
11761 to their underlying values. */
11763 {
11766 }
11770 /* Handle Objective-C++ constructs, if appropriate. */
11771 {
11772 tree subst
11777 }
11779 }
11781 #undef RECUR
11782 }
11784 /* Verify that the instantiated ARGS are valid. For type arguments,
11785 make sure that the type's linkage is ok. For non-type arguments,
11786 make sure they are constants if they are integral or enumerations.
11787 Emit an error under control of COMPLAIN, and return TRUE on error. */
11789 static bool
11791 {
11793 {
11803 }
11805 {
11806 /* [basic.link]: A name with no linkage (notably, the name
11807 of a class or enumeration declared in a local scope)
11808 shall not be used to declare an entity with linkage.
11809 This implies that names with no linkage cannot be used as
11810 template arguments. */
11814 {
11815 /* DR 488 makes use of a type with no linkage cause
11816 type deduction to fail. */
11818 {
11821 else
11824 }
11826 }
11827 /* In order to avoid all sorts of complications, we do not
11828 allow variably-modified types as template arguments. */
11830 {
11834 }
11835 }
11836 /* A non-type argument of integral or enumerated type must be a
11837 constant. */
11841 {
11845 }
11847 }
11849 static bool
11851 {
11856 {
11859 }
11863 }
11865 /* Instantiate the indicated variable or function template TMPL with
11866 the template arguments in TARG_PTR. */
11868 tree
11870 {
11871 tree fndecl;
11872 tree gen_tmpl;
11873 tree spec;
11874 HOST_WIDE_INT saved_processing_template_decl;
11881 /* If this function is a clone, handle it specially. */
11883 {
11884 tree spec;
11885 tree clone;
11888 complain);
11892 /* Look for the clone. */
11896 /* We should always have found the clone by now. */
11899 }
11901 /* Check to see if we already have this specialization. */
11909 {
11910 /* The TMPL is a partial instantiation. To get a full set of
11911 arguments we must add the arguments used to perform the
11912 partial instantiation. */
11914 targ_ptr);
11916 /* Check to see if we already have this specialization. */
11921 }
11924 complain))
11927 /* We are building a FUNCTION_DECL, during which the access of its
11928 parameters and return types have to be checked. However this
11929 FUNCTION_DECL which is the desired context for access checking
11930 is not built yet. We solve this chicken-and-egg problem by
11931 deferring all checks until we have the FUNCTION_DECL. */
11934 /* Although PROCESSING_TEMPLATE_DECL may be true at this point
11935 (because, for example, we have encountered a non-dependent
11936 function call in the body of a template function and must now
11937 determine which of several overloaded functions will be called),
11938 within the instantiation itself we are not processing a
11939 template. */
11942 /* Substitute template parameters to obtain the specialization. */
11949 /* Now we know the specialization, compute access previously
11950 deferred. */
11956 /* The DECL_TI_TEMPLATE should always be the immediate parent
11957 template, not the most general template. */
11960 /* If we've just instantiated the main entry point for a function,
11961 instantiate all the alternate entry points as well. We do this
11962 by cloning the instantiation of the main entry point, not by
11963 instantiating the template clones. */
11968 }
11970 /* The FN is a TEMPLATE_DECL for a function. The ARGS are the
11971 arguments that are being used when calling it. TARGS is a vector
11972 into which the deduced template arguments are placed.
11974 Return zero for success, 2 for an incomplete match that doesn't resolve
11975 all the types, and 1 for complete failure. An error message will be
11976 printed only for an incomplete match.
11978 If FN is a conversion operator, or we are trying to produce a specific
11979 specialization, RETURN_TYPE is the return type desired.
11981 The EXPLICIT_TARGS are explicit template arguments provided via a
11982 template-id.
11984 The parameter STRICT is one of:
11986 DEDUCE_CALL:
11987 We are deducing arguments for a function call, as in
11988 [temp.deduct.call].
11990 DEDUCE_CONV:
11991 We are deducing arguments for a conversion function, as in
11992 [temp.deduct.conv].
11994 DEDUCE_EXACT:
11995 We are deducing arguments when doing an explicit instantiation
11996 as in [temp.explicit], when determining an explicit specialization
11997 as in [temp.expl.spec], or when taking the address of a function
11998 template, as in [temp.deduct.funcaddr]. */
12000 int
12002 tree explicit_targs,
12003 tree targs,
12004 tree args,
12005 tree return_type,
12006 unification_kind_t strict,
12008 {
12009 tree parms;
12010 tree fntype;
12018 {
12019 /* [temp.deduct]
12021 The specified template arguments must match the template
12022 parameters in kind (i.e., type, nontype, template), and there
12023 must not be more arguments than there are parameters;
12024 otherwise type deduction fails.
12026 Nontype arguments must match the types of the corresponding
12027 nontype template parameters, or must be convertible to the
12028 types of the corresponding nontype parameters as specified in
12029 _temp.arg.nontype_, otherwise type deduction fails.
12031 All references in the function type of the function template
12032 to the corresponding template parameters are replaced by the
12033 specified template argument values. If a substitution in a
12034 template parameter or in the function type of the function
12035 template results in an invalid type, type deduction fails. */
12038 tree converted_args;
12044 converted_args
12051 /* Substitute the explicit args into the function type. This is
12052 necessary so that, for instance, explicitly declared function
12053 arguments can match null pointed constants. If we were given
12054 an incomplete set of explicit args, we must not do semantic
12055 processing during substitution as we could create partial
12056 instantiations. */
12058 {
12062 /* Dig out the actual parm. */
12065 {
12068 }
12070 {
12073 }
12076 {
12078 tree targ;
12081 /* Mark the argument pack as "incomplete". We could
12082 still deduce more arguments during unification. */
12085 {
12089 }
12091 /* We have some incomplete argument packs. */
12093 }
12094 }
12097 /* Any substitution is guaranteed to be incomplete if there
12098 are incomplete argument packs, because we can still deduce
12099 more arguments. */
12101 else
12111 /* Place the explicitly specified arguments in TARGS. */
12114 }
12116 /* Never do unification on the 'this' parameter. */
12120 {
12123 }
12125 /* We allow incomplete unification without an error message here
12126 because the standard doesn't seem to explicitly prohibit it. Our
12127 callers must be ready to deal with unification failures in any
12128 event. */
12134 {
12137 /* Clear the "incomplete" flags on all argument packs. */
12139 {
12142 {
12145 }
12146 }
12147 }
12149 /* Now that we have bindings for all of the template arguments,
12150 ensure that the arguments deduced for the template template
12151 parameters have compatible template parameter lists. We cannot
12152 check this property before we have deduced all template
12153 arguments, because the template parameter types of a template
12154 template parameter might depend on prior template parameters
12155 deduced after the template template parameter. The following
12156 ill-formed example illustrates this issue:
12158 template<typename T, template<T> class C> void f(C<5>, T);
12160 template<int N> struct X {};
12162 void g() {
12163 f(X<5>(), 5l); // error: template argument deduction fails
12164 }
12166 The template parameter list of 'C' depends on the template type
12167 parameter 'T', but 'C' is deduced to 'X' before 'T' is deduced to
12168 'long'. Thus, we can't check that 'C' cannot bind to 'X' at the
12169 time that we deduce 'C'. */
12171 && !template_template_parm_bindings_ok_p
12176 /* All is well so far. Now, check:
12178 [temp.deduct]
12180 When all template arguments have been deduced, all uses of
12181 template parameters in nondeduced contexts are replaced with
12182 the corresponding deduced argument values. If the
12183 substitution results in an invalid type, as described above,
12184 type deduction fails. */
12190 }
12192 /* Adjust types before performing type deduction, as described in
12193 [temp.deduct.call] and [temp.deduct.conv]. The rules in these two
12194 sections are symmetric. PARM is the type of a function parameter
12195 or the return type of the conversion function. ARG is the type of
12196 the argument passed to the call, or the type of the value
12197 initialized with the result of the conversion function.
12198 ARG_EXPR is the original argument expression, which may be null. */
12200 static int
12204 tree arg_expr)
12205 {
12209 {
12214 {
12215 /* Swap PARM and ARG throughout the remainder of this
12216 function; the handling is precisely symmetric since PARM
12217 will initialize ARG rather than vice versa. */
12222 }
12225 /* There is nothing to do in this case. */
12230 }
12233 {
12234 /* [temp.deduct.call]
12236 If P is not a reference type:
12238 --If A is an array type, the pointer type produced by the
12239 array-to-pointer standard conversion (_conv.array_) is
12240 used in place of A for type deduction; otherwise,
12242 --If A is a function type, the pointer type produced by
12243 the function-to-pointer standard conversion
12244 (_conv.func_) is used in place of A for type deduction;
12245 otherwise,
12247 --If A is a cv-qualified type, the top level
12248 cv-qualifiers of A's type are ignored for type
12249 deduction. */
12254 else
12256 }
12258 /* From C++0x [14.8.2.1/3 temp.deduct.call] (after DR606), "If P is
12259 of the form T&&, where T is a template parameter, and the argument
12260 is an lvalue, T is deduced as A& */
12268 /* [temp.deduct.call]
12270 If P is a cv-qualified type, the top level cv-qualifiers
12271 of P's type are ignored for type deduction. If P is a
12272 reference type, the type referred to by P is used for
12273 type deduction. */
12276 {
12279 }
12281 /* DR 322. For conversion deduction, remove a reference type on parm
12282 too (which has been swapped into ARG). */
12287 }
12289 /* Most parms like fn_type_unification.
12291 If SUBR is 1, we're being called recursively (to unify the
12292 arguments of a function or method parameter of a function
12293 template). */
12295 static int
12297 tree targs,
12298 tree xparms,
12299 tree xargs,
12301 unification_kind_t strict,
12303 {
12317 {
12333 }
12335 again:
12341 {
12354 /* We can't deduce anything from this, but we might get all the
12355 template args from other function args. */
12358 /* Conversions will be performed on a function argument that
12359 corresponds with a function parameter that contains only
12360 non-deducible template parameters and explicitly specified
12361 template parameters. */
12363 {
12364 tree type;
12368 else
12375 flags))
12379 }
12382 {
12385 {
12386 /* [temp.deduct.type]
12388 A template-argument can be deduced from a pointer to
12389 function or pointer to member function argument if
12390 the set of overloaded functions does not contain
12391 function templates and at most one of a set of
12392 overloaded functions provides a unique match. */
12398 }
12403 }
12405 {
12410 arg_expr);
12416 }
12417 }
12423 {
12424 /* Unify the remaining arguments with the pack expansion type. */
12425 tree argvec;
12428 tree t;
12430 /* Count the number of arguments that remain. */
12432 len++;
12434 /* Allocate a TREE_VEC and copy in all of the arguments */
12437 {
12440 }
12442 /* Copy the parameter into parmvec. */
12448 /* Advance to the end of the list of parameters. */
12450 }
12452 /* Fail if we've reached the end of the parm list, and more args
12453 are present, and the parm list isn't variadic. */
12456 /* Fail if parms are left and they don't have default values. */
12464 {
12465 tree tparm;
12472 /* If this is an undeduced nontype parameter that depends on
12473 a type parameter, try another pass; its type may have been
12474 deduced from a later argument than the one from which
12475 this parameter can be deduced. */
12481 /* Core issue #226 (C++0x) [temp.deduct]:
12483 If a template argument has not been deduced, its
12484 default template argument, if any, is used.
12486 When we are in C++98 mode, TREE_PURPOSE will either
12487 be NULL_TREE or ERROR_MARK_NODE, so we do not need
12488 to explicitly check cxx_dialect here. */
12490 {
12495 else
12496 {
12499 }
12500 }
12502 /* If the type parameter is a parameter pack, then it will
12503 be deduced to an empty parameter pack. */
12505 {
12506 tree arg;
12509 {
12513 }
12514 else
12521 }
12524 }
12527 }
12529 /* Subroutine of type_unification_real. Args are like the variables
12530 at the call site. ARG is an overloaded function (or template-id);
12531 we try deducing template args from each of the overloads, and if
12532 only one succeeds, we go with that. Modifies TARGS and returns
12533 true on success. */
12535 static bool
12537 tree targs,
12538 tree parm,
12539 tree arg,
12540 unification_kind_t strict,
12542 {
12548 {
12551 }
12552 else
12556 /* Handle `&x' where `x' is some static or non-static member
12557 function name. */
12563 /* Strip baselink information. */
12568 {
12569 /* If we got some explicit template args, we need to plug them into
12570 the affected templates before we try to unify, in case the
12571 explicit args will completely resolve the templates in question. */
12577 {
12588 {
12592 }
12594 }
12595 }
12598 /* If ARG is, for example, "(0, &f)" then its type will be unknown
12599 -- but the deduction does not succeed because the expression is
12600 not just the function on its own. */
12602 else
12608 /* [temp.deduct.type] A template-argument can be deduced from a pointer
12609 to function or pointer to member function argument if the set of
12610 overloaded functions does not contain function templates and at most
12611 one of a set of overloaded functions provides a unique match.
12613 So if we found multiple possibilities, we return success but don't
12614 deduce anything. */
12617 {
12622 }
12627 }
12629 /* Subroutine of resolve_overloaded_unification; does deduction for a single
12630 overload. Fills TARGS with any deduced arguments, or error_mark_node if
12631 different overloads deduce different arguments for a given parm.
12632 ADDR_P is true if the expression for which deduction is being
12633 performed was of the form "& fn" rather than simply "fn".
12635 Returns 1 on success. */
12637 static int
12639 tree orig_targs,
12640 tree targs,
12641 tree parm,
12642 tree arg,
12643 unification_kind_t strict,
12646 {
12648 tree tempargs;
12651 /* [temp.deduct.type] A template-argument can be deduced from a pointer
12652 to function or pointer to member function argument if the set of
12653 overloaded functions does not contain function templates and at most
12654 one of a set of overloaded functions provides a unique match.
12656 So if this is a template, just return success. */
12668 /* We don't copy orig_targs for this because if we have already deduced
12669 some template args from previous args, unify would complain when we
12670 try to deduce a template parameter for the same argument, even though
12671 there isn't really a conflict. */
12678 /* First make sure we didn't deduce anything that conflicts with
12679 explicitly specified args. */
12681 {
12688 /* Since we're unifying against ourselves, we will fill in
12689 template args used in the function parm list with our own
12690 template parms. Discard them. */
12694 }
12697 {
12702 }
12705 }
12707 /* PARM is a template class (perhaps with unbound template
12708 parameters). ARG is a fully instantiated type. If ARG can be
12709 bound to PARM, return ARG, otherwise return NULL_TREE. TPARMS and
12710 TARGS are as for unify. */
12712 static tree
12714 {
12715 tree copy_of_targs;
12722 /* We need to make a new template argument vector for the call to
12723 unify. If we used TARGS, we'd clutter it up with the result of
12724 the attempted unification, even if this class didn't work out.
12725 We also don't want to commit ourselves to all the unifications
12726 we've already done, since unification is supposed to be done on
12727 an argument-by-argument basis. In other words, consider the
12728 following pathological case:
12730 template <int I, int J, int K>
12731 struct S {};
12733 template <int I, int J>
12734 struct S<I, J, 2> : public S<I, I, I>, S<J, J, J> {};
12736 template <int I, int J, int K>
12737 void f(S<I, J, K>, S<I, I, I>);
12739 void g() {
12740 S<0, 0, 0> s0;
12741 S<0, 1, 2> s2;
12743 f(s0, s2);
12744 }
12746 Now, by the time we consider the unification involving `s2', we
12747 already know that we must have `f<0, 0, 0>'. But, even though
12748 `S<0, 1, 2>' is derived from `S<0, 0, 0>', the code is invalid
12749 because there are two ways to unify base classes of S<0, 1, 2>
12750 with S<I, I, I>. If we kept the already deduced knowledge, we
12751 would reject the possibility I=1. */
12754 /* If unification failed, we're done. */
12760 }
12762 /* Given a template type PARM and a class type ARG, find the unique
12763 base type in ARG that is an instance of PARM. We do not examine
12764 ARG itself; only its base-classes. If there is not exactly one
12765 appropriate base class, return NULL_TREE. PARM may be the type of
12766 a partial specialization, as well as a plain template type. Used
12767 by unify. */
12769 static tree
12771 {
12773 tree binfo;
12779 /* The type could not be completed. */
12782 /* Walk in inheritance graph order. The search order is not
12783 important, and this avoids multiple walks of virtual bases. */
12785 {
12789 {
12790 /* If there is more than one satisfactory baseclass, then:
12792 [temp.deduct.call]
12794 If they yield more than one possible deduced A, the type
12795 deduction fails.
12797 applies. */
12802 }
12803 }
12806 }
12808 /* Returns the level of DECL, which declares a template parameter. */
12810 static int
12812 {
12814 {
12824 }
12826 }
12828 /* Decide whether ARG can be unified with PARM, considering only the
12829 cv-qualifiers of each type, given STRICT as documented for unify.
12830 Returns nonzero iff the unification is OK on that basis. */
12832 static int
12834 {
12840 {
12841 /* Although a CVR qualifier is ignored when being applied to a
12842 substituted template parameter ([8.3.2]/1 for example), that
12843 does not apply during deduction [14.8.2.4]/1, (even though
12844 that is not explicitly mentioned, [14.8.2.4]/9 indicates
12845 this). Except when we're allowing additional CV qualifiers
12846 at the outer level [14.8.2.1]/3,1st bullet. */
12856 }
12867 }
12869 /* Determines the LEVEL and INDEX for the template parameter PARM. */
12870 void
12872 {
12876 {
12879 }
12880 else
12881 {
12884 }
12885 }
12887 /* Unifies the remaining arguments in PACKED_ARGS with the pack
12888 expansion at the end of PACKED_PARMS. Returns 0 if the type
12889 deduction succeeds, 1 otherwise. STRICT is the same as in
12890 unify. CALL_ARGS_P is true iff PACKED_ARGS is actually a function
12891 call argument list. We'll need to adjust the arguments to make them
12892 types. SUBR tells us if this is from a recursive call to
12893 type_unification_real. */
12894 int
12898 {
12899 tree parm
12906 /* Determine the parameter packs we will be deducing from the
12907 pattern, and record their current deductions. */
12910 {
12914 /* Determine the index and level of this parameter pack. */
12917 /* Keep track of the parameter packs and their corresponding
12918 argument packs. */
12921 }
12923 /* Loop through all of the arguments that have not yet been
12924 unified and unify each with the pattern. */
12926 {
12929 /* For each parameter pack, clear out the deduced value so that
12930 we can deduce it again. */
12932 {
12937 }
12939 /* Unify the pattern with the current argument. */
12940 {
12947 {
12950 /* This mirrors what we do in type_unification_real. */
12952 {
12954 sub_strict = (UNIFY_ALLOW_OUTER_LEVEL
12955 | UNIFY_ALLOW_MORE_CV_QUAL
12969 }
12972 {
12975 {
12976 /* [temp.deduct.type] A template-argument can be
12977 deduced from a pointer to function or pointer
12978 to member function argument if the set of
12979 overloaded functions does not contain function
12980 templates and at most one of a set of
12981 overloaded functions provides a unique
12982 match. */
12989 }
12992 {
12997 }
12998 }
13003 arg_strict |=
13005 arg_expr);
13006 }
13009 {
13012 }
13013 }
13015 /* For each parameter pack, collect the deduced value. */
13017 {
13023 }
13024 }
13026 /* Verify that the results of unification with the parameter packs
13027 produce results consistent with what we've seen before, and make
13028 the deduced argument packs available. */
13030 {
13036 /* If NEW_ARGS contains any NULL_TREE entries, we didn't
13037 actually deduce anything. */
13045 {
13046 /* Prepend the explicit arguments onto NEW_ARGS. */
13052 /* Copy the explicit arguments. */
13057 /* Copy the deduced arguments. */
13061 }
13064 {
13065 tree result;
13070 /* Build the deduced *_ARGUMENT_PACK. */
13072 {
13077 }
13078 else
13083 /* Note the deduced argument packs for this parameter
13084 pack. */
13086 }
13090 {
13091 /* We only had the explicitly-provided arguments before, but
13092 now we have a complete set of arguments. */
13097 /* Keep the original deduced argument pack. */
13103 }
13105 new_args))
13106 /* Inconsistent unification of this parameter pack. */
13108 else
13109 {
13114 /* Keep the original deduced argument pack. */
13116 }
13117 }
13120 }
13122 /* Deduce the value of template parameters. TPARMS is the (innermost)
13123 set of template parameters to a template. TARGS is the bindings
13124 for those template parameters, as determined thus far; TARGS may
13125 include template arguments for outer levels of template parameters
13126 as well. PARM is a parameter to a template function, or a
13127 subcomponent of that parameter; ARG is the corresponding argument.
13128 This function attempts to match PARM with ARG in a manner
13129 consistent with the existing assignments in TARGS. If more values
13130 are deduced, then TARGS is updated.
13132 Returns 0 if the type deduction succeeds, 1 otherwise. The
13133 parameter STRICT is a bitwise or of the following flags:
13135 UNIFY_ALLOW_NONE:
13136 Require an exact match between PARM and ARG.
13137 UNIFY_ALLOW_MORE_CV_QUAL:
13138 Allow the deduced ARG to be more cv-qualified (by qualification
13139 conversion) than ARG.
13140 UNIFY_ALLOW_LESS_CV_QUAL:
13141 Allow the deduced ARG to be less cv-qualified than ARG.
13142 UNIFY_ALLOW_DERIVED:
13143 Allow the deduced ARG to be a template base class of ARG,
13144 or a pointer to a template base class of the type pointed to by
13145 ARG.
13146 UNIFY_ALLOW_INTEGER:
13147 Allow any integral type to be deduced. See the TEMPLATE_PARM_INDEX
13148 case for more information.
13149 UNIFY_ALLOW_OUTER_LEVEL:
13150 This is the outermost level of a deduction. Used to determine validity
13151 of qualification conversions. A valid qualification conversion must
13152 have const qualified pointers leading up to the inner type which
13153 requires additional CV quals, except at the outer level, where const
13154 is not required [conv.qual]. It would be normal to set this flag in
13155 addition to setting UNIFY_ALLOW_MORE_CV_QUAL.
13156 UNIFY_ALLOW_OUTER_MORE_CV_QUAL:
13157 This is the outermost level of a deduction, and PARM can be more CV
13158 qualified at this point.
13159 UNIFY_ALLOW_OUTER_LESS_CV_QUAL:
13160 This is the outermost level of a deduction, and PARM can be less CV
13161 qualified at this point. */
13163 static int
13165 {
13167 tree targ;
13168 tree tparm;
13171 /* I don't think this will do the right thing with respect to types.
13172 But the only case I've seen it in so far has been array bounds, where
13173 signedness is the only information lost, and I think that will be
13174 okay. */
13182 /* We can't deduce anything from this, but we might get all the
13183 template args from other function args. */
13186 /* If PARM uses template parameters, then we can't bail out here,
13187 even if ARG == PARM, since we won't record unifications for the
13188 template parameters. We might need them if we're trying to
13189 figure out which of two things is more specialized. */
13193 /* Handle init lists early, so the rest of the function can assume
13194 we're dealing with a type. */
13196 {
13201 /* We can only deduce from an initializer list argument if the
13202 parameter is std::initializer_list; otherwise this is a
13203 non-deduced context. */
13209 {
13212 {
13214 /* It should only be possible to get here for a call. */
13216 elt_strict |= maybe_adjust_types_for_deduction
13219 }
13223 }
13225 }
13227 /* Immediately reject some pairs that won't unify because of
13228 cv-qualification mismatches. */
13231 /* It is the elements of the array which hold the cv quals of an array
13232 type, and the elements might be template type parms. We'll check
13233 when we recurse. */
13235 /* We check the cv-qualifiers when unifying with template type
13236 parameters below. We want to allow ARG `const T' to unify with
13237 PARM `T' for example, when computing which of two templates
13238 is more specialized, for example. */
13252 {
13256 /* In a type which contains a nested-name-specifier, template
13257 argument values cannot be deduced for template parameters used
13258 within the nested-name-specifier. */
13270 /* The PARM is not one we're trying to unify. Just check
13271 to see if it matches ARG. */
13278 /* Check for mixed types and values. */
13286 {
13287 /* ARG must be constructed from a template class or a template
13288 template parameter. */
13293 {
13296 tree parm_parms
13297 = DECL_INNERMOST_TEMPLATE_PARMS
13302 /* The resolution to DR150 makes clear that default
13303 arguments for an N-argument may not be used to bind T
13304 to a template template parameter with fewer than N
13305 parameters. It is not safe to permit the binding of
13306 default arguments as an extension, as that may change
13307 the meaning of a conforming program. Consider:
13309 struct Dense { static const unsigned int dim = 1; };
13311 template <template <typename> class View,
13312 typename Block>
13313 void operator+(float, View<Block> const&);
13315 template <typename Block,
13316 unsigned int Dim = Block::dim>
13317 struct Lvalue_proxy { operator float() const; };
13319 void
13320 test_1d (void) {
13321 Lvalue_proxy<Dense> p;
13322 float b;
13323 b + p;
13324 }
13326 Here, if Lvalue_proxy is permitted to bind to View, then
13327 the global operator+ will be used; if they are not, the
13328 Lvalue_proxy will be converted to float. */
13330 argvec,
13332 tf_none,
13338 /* Deduce arguments T, i from TT<T> or TT<i>.
13339 We check each element of PARMVEC and ARGVEC individually
13340 rather than the whole TREE_VEC since they can have
13341 different number of elements. */
13348 /* Check if the parameters end in a pack, making them
13349 variadic. */
13358 {
13362 UNIFY_ALLOW_NONE))
13364 }
13369 UNIFY_ALLOW_NONE,
13373 }
13376 /* Fall through to deduce template name. */
13377 }
13381 {
13382 /* Deduce template name TT from TT, TT<>, TT<T> and TT<i>. */
13384 /* Simple cases: Value already set, does match or doesn't. */
13389 }
13390 else
13391 {
13392 /* If PARM is `const T' and ARG is only `int', we don't have
13393 a match unless we are allowing additional qualification.
13394 If ARG is `const int' and PARM is just `T' that's OK;
13395 that binds `const int' to `T'. */
13400 /* Consider the case where ARG is `const volatile int' and
13401 PARM is `const T'. Then, T should be `volatile int'. */
13402 arg = cp_build_qualified_type_real
13407 /* Simple cases: Value already set, does match or doesn't. */
13413 /* Make sure that ARG is not a variable-sized array. (Note
13414 that were talking about variable-sized arrays (like
13415 `int[n]'), rather than arrays of unknown size (like
13416 `int[]').) We'll get very confused by such a type since
13417 the bound of the array will not be computable in an
13418 instantiation. Besides, such types are not allowed in
13419 ISO C++, so we can do as we please here. */
13422 }
13424 /* If ARG is a parameter pack or an expansion, we cannot unify
13425 against it unless PARM is also a parameter pack. */
13440 /* The PARM is not one we're trying to unify. Just check
13441 to see if it matches ARG. */
13451 /* [temp.deduct.type] If, in the declaration of a function template
13452 with a non-type template-parameter, the non-type
13453 template-parameter is used in an expression in the function
13454 parameter-list and, if the corresponding template-argument is
13455 deduced, the template-argument type shall match the type of the
13456 template-parameter exactly, except that a template-argument
13457 deduced from an array bound may be of any integral type.
13458 The non-type parameter might use already deduced type parameters. */
13461 /* Template-parameter dependent expression. Just accept it for now.
13462 It will later be processed in convert_template_argument. */
13463 ;
13469 /* Convert the ARG to the type of PARM; the deduced non-type
13470 template argument must exactly match the types of the
13471 corresponding parameter. */
13474 /* We haven't deduced the type of this parameter yet. Try again
13475 later. */
13477 else
13480 /* If ARG is a parameter pack or an expansion, we cannot unify
13481 against it unless PARM is also a parameter pack. */
13490 {
13491 /* A pointer-to-member constant can be unified only with
13492 another constant. */
13496 /* Just unify the class member. It would be useless (and possibly
13497 wrong, depending on the strict flags) to unify also
13498 PTRMEM_CST_CLASS, because we want to be sure that both parm and
13499 arg refer to the same variable, even if through different
13500 classes. For instance:
13502 struct A { int x; };
13503 struct B : A { };
13505 Unification of &A::x and &B::x must succeed. */
13508 }
13511 {
13515 /* [temp.deduct.call]
13517 A can be another pointer or pointer to member type that can
13518 be converted to the deduced A via a qualification
13519 conversion (_conv.qual_).
13521 We pass down STRICT here rather than UNIFY_ALLOW_NONE.
13522 This will allow for additional cv-qualification of the
13523 pointed-to types if appropriate. */
13526 /* The derived-to-base conversion only persists through one
13527 level of pointers. */
13532 }
13547 {
13548 tree parm_max;
13549 tree arg_max;
13553 /* Our representation of array types uses "N - 1" as the
13554 TYPE_MAX_VALUE for an array with "N" elements, if "N" is
13555 not an integer constant. We cannot unify arbitrarily
13556 complex expressions, so we eliminate the MINUS_EXPRs
13557 here. */
13561 {
13564 }
13568 {
13569 /* The ARG_MAX may not be a simple MINUS_EXPR, if we are
13570 trying to unify the type of a variable with the type
13571 of a template parameter. For example:
13573 template <unsigned int N>
13574 void f (char (&) [N]);
13575 int g();
13576 void h(int i) {
13577 char a[g(i)];
13578 f(a);
13579 }
13581 Here, the type of the ARG will be "int [g(i)]", and
13582 may be a SAVE_EXPR, etc. */
13586 }
13588 /* If only one of the bounds used a MINUS_EXPR, compensate
13589 by adding one to the other bound. */
13592 integer_type_node,
13593 parm_max,
13594 integer_one_node);
13597 integer_type_node,
13598 arg_max,
13599 integer_one_node);
13603 }
13617 /* We have already checked cv-qualification at the top of the
13618 function. */
13622 /* As far as unification is concerned, this wins. Later checks
13623 will invalidate it if necessary. */
13626 /* Types INTEGER_CST and MINUS_EXPR can come from array bounds. */
13627 /* Type INTEGER_CST can come from ordinary constant template args. */
13637 {
13646 UNIFY_ALLOW_NONE))
13649 }
13657 {
13664 strict);
13665 }
13668 {
13672 {
13673 /* First, we try to unify the PARM and ARG directly. */
13678 {
13679 /* Fallback to the special case allowed in
13680 [temp.deduct.call]:
13682 If P is a class, and P has the form
13683 template-id, then A can be a derived class of
13684 the deduced A. Likewise, if P is a pointer to
13685 a class of the form template-id, A can be a
13686 pointer to a derived class pointed to by the
13687 deduced A. */
13692 }
13693 }
13697 /* Perhaps PARM is something like S<U> and ARG is S<int>.
13698 Then, we should unify `int' and `U'. */
13700 else
13701 /* There's no chance of unification succeeding. */
13706 }
13716 /* CV qualifications for methods can never be deduced, they must
13717 match exactly. We need to check them explicitly here,
13718 because type_unification_real treats them as any other
13719 cv-qualified parameter. */
13721 && (!check_cv_quals_for_unify
13732 LOOKUP_NORMAL);
13735 /* Unify a pointer to member with a pointer to member function, which
13736 deduces the type of the member as a function type. */
13738 {
13739 tree method_type;
13740 tree fntype;
13741 cp_cv_quals cv_quals;
13743 /* Check top-level cv qualifiers */
13751 /* Determine the type of the function we are unifying against. */
13753 fntype =
13757 /* Extract the cv-qualifiers of the member function from the
13758 implicit object parameter and place them on the function
13759 type to be restored later. */
13760 cv_quals =
13764 }
13772 strict);
13783 /* Matched cases are handled by the ARG == PARM test above. */
13788 {
13796 {
13798 {
13800 /* We can unify against something with a trailing
13801 parameter pack. */
13803 else
13804 /* Since there is something following the pack
13805 expansion, we cannot unify this template argument
13806 list. */
13808 }
13809 }
13812 /* If we don't have enough arguments to satisfy the parameters
13813 (not counting the pack expression at the end), or we have
13814 too many arguments for a parameter list that doesn't end in
13815 a pack expression, we can't unify. */
13820 /* Unify all of the parameters that precede the (optional)
13821 pack expression. */
13823 {
13827 }
13835 }
13841 /* Cannot deduce anything from TYPEOF_TYPE or DECLTYPE_TYPE
13842 nodes. */
13846 /* Unification fails if we hit an error node. */
13852 /* We must be looking at an expression. This can happen with
13853 something like:
13855 template <int I>
13856 void foo(S<I>, S<I + 2>);
13858 This is a "nondeduced context":
13860 [deduct.type]
13862 The nondeduced contexts are:
13864 --A type that is a template-id in which one or more of
13865 the template-arguments is an expression that references
13866 a template-parameter.
13868 In these cases, we assume deduction succeeded, but don't
13869 actually infer any unifications. */
13874 else
13876 }
13877 }
13878 \f
13879 /* Note that DECL can be defined in this translation unit, if
13880 required. */
13882 static void
13884 {
13885 tree clone;
13889 }
13891 /* Called if RESULT is explicitly instantiated, or is a member of an
13892 explicitly instantiated class. */
13894 void
13896 {
13899 /* If this entity has already been written out, it's too late to
13900 make any modifications. */
13905 /* The TREE_PUBLIC flag for function declarations will have been
13906 set correctly by tsubst. */
13909 /* This might have been set by an earlier implicit instantiation. */
13914 else
13915 {
13917 /* Always make artificials weak. */
13920 /* For WIN32 we also want to put explicit instantiations in
13921 linkonce sections. */
13924 }
13926 /* If EXTERN_P, then this function will not be emitted -- unless
13927 followed by an explicit instantiation, at which point its linkage
13928 will be adjusted. If !EXTERN_P, then this function will be
13929 emitted here. In neither circumstance do we want
13930 import_export_decl to adjust the linkage. */
13932 }
13934 /* Given two function templates PAT1 and PAT2, return:
13936 1 if PAT1 is more specialized than PAT2 as described in [temp.func.order].
13937 -1 if PAT2 is more specialized than PAT1.
13938 0 if neither is more specialized.
13940 LEN indicates the number of parameters we should consider
13941 (defaulted parameters should not be considered).
13943 The 1998 std underspecified function template partial ordering, and
13944 DR214 addresses the issue. We take pairs of arguments, one from
13945 each of the templates, and deduce them against each other. One of
13946 the templates will be more specialized if all the *other*
13947 template's arguments deduce against its arguments and at least one
13948 of its arguments *does* *not* deduce against the other template's
13949 corresponding argument. Deduction is done as for class templates.
13950 The arguments used in deduction have reference and top level cv
13951 qualifiers removed. Iff both arguments were originally reference
13952 types *and* deduction succeeds in both directions, the template
13953 with the more cv-qualified argument wins for that pairing (if
13954 neither is more cv-qualified, they both are equal). Unlike regular
13955 deduction, after all the arguments have been deduced in this way,
13956 we do *not* verify the deduced template argument values can be
13957 substituted into non-deduced contexts, nor do we have to verify
13958 that all template arguments have been deduced. */
13960 int
13962 {
13974 /* Remove the this parameter from non-static member functions. If
13975 one is a non-static member function and the other is not a static
13976 member function, remove the first parameter from that function
13977 also. This situation occurs for operator functions where we
13978 locate both a member function (with this pointer) and non-member
13979 operator (with explicit first operand). */
13981 {
13986 }
13988 {
13991 {
13992 len--;
13994 }
13995 }
13997 /* If only one is a conversion operator, they are unordered. */
14001 /* Consider the return type for a conversion function */
14003 {
14006 len++;
14007 }
14009 processing_template_decl++;
14012 /* Stop when an ellipsis is seen. */
14014 {
14023 {
14024 /* When both arguments are pack expansions, we need only
14025 unify the patterns themselves. */
14029 /* This is the last comparison we need to do. */
14031 }
14034 {
14037 }
14040 {
14043 }
14046 {
14047 /* Only of the args is a reference, see if we should apply
14048 array/function pointer decay to it. This is not part of
14049 DR214, but is, IMHO, consistent with the deduction rules
14050 for the function call itself, and with our earlier
14051 implementation of the underspecified partial ordering
14052 rules. (nathan). */
14054 {
14056 {
14059 /* FALLTHROUGH. */
14066 }
14067 }
14068 else
14069 {
14071 {
14074 /* FALLTHROUGH. */
14081 }
14082 }
14083 }
14089 {
14095 /* Setup the parameter vector, which contains only ARG1. */
14098 /* Setup the argument vector, which contains the remaining
14099 arguments. */
14108 /* We cannot deduce in the other direction, because ARG1 is
14109 a pack expansion but ARG2 is not. */
14111 }
14113 {
14119 /* Setup the parameter vector, which contains only ARG1. */
14122 /* Setup the argument vector, which contains the remaining
14123 arguments. */
14132 /* We cannot deduce in the other direction, because ARG2 is
14133 a pack expansion but ARG1 is not.*/
14135 }
14137 else
14138 {
14139 /* The normal case, where neither argument is a pack
14140 expansion. */
14143 }
14150 /* We've failed to deduce something in either direction.
14151 These must be unordered. */
14155 {
14156 /* Deduces in both directions, see if quals can
14157 disambiguate. Pretend the worse one failed to deduce. */
14162 }
14170 /* We have already processed all of the arguments in our
14171 handing of the pack expansion type. */
14176 }
14178 processing_template_decl--;
14180 /* All things being equal, if the next argument is a pack expansion
14181 for one function but not for the other, prefer the
14182 non-variadic function. */
14186 {
14191 }
14194 }
14196 /* Determine which of two partial specializations is more specialized.
14198 PAT1 is a TREE_LIST whose TREE_TYPE is the _TYPE node corresponding
14199 to the first partial specialization. The TREE_VALUE is the
14200 innermost set of template parameters for the partial
14201 specialization. PAT2 is similar, but for the second template.
14203 Return 1 if the first partial specialization is more specialized;
14204 -1 if the second is more specialized; 0 if neither is more
14205 specialized.
14207 See [temp.class.order] for information about determining which of
14208 two templates is more specialized. */
14210 static int
14212 {
14213 tree targs;
14221 /* Just like what happens for functions, if we are ordering between
14222 different class template specializations, we may encounter dependent
14223 types in the arguments, and we need our dependency check functions
14224 to behave correctly. */
14230 {
14233 }
14239 {
14242 }
14245 /* In the case of a tie where at least one of the class templates
14246 has a parameter pack at the end, the template with the most
14247 non-packed parameters wins. */
14249 && any_deductions
14252 {
14258 /* We don't count the pack expansion at the end. */
14268 }
14271 }
14273 /* Return the template arguments that will produce the function signature
14274 DECL from the function template FN, with the explicit template
14275 arguments EXPLICIT_ARGS. If CHECK_RETTYPE is true, the return type must
14276 also match. Return NULL_TREE if no satisfactory arguments could be
14277 found. */
14279 static tree
14281 {
14284 tree decl_type;
14285 tree decl_arg_types;
14287 /* Substitute the explicit template arguments into the type of DECL.
14288 The call to fn_type_unification will handle substitution into the
14289 FN. */
14292 {
14293 tree tmpl;
14294 tree converted_args;
14298 else
14299 /* We can get here for some invalid specializations. */
14302 converted_args
14305 tf_none,
14314 }
14316 /* Never do unification on the 'this' parameter. */
14321 decl_arg_types,
14328 }
14330 /* Return the innermost template arguments that, when applied to a
14331 template specialization whose innermost template parameters are
14332 TPARMS, and whose specialization arguments are PARMS, yield the
14333 ARGS.
14335 For example, suppose we have:
14337 template <class T, class U> struct S {};
14338 template <class T> struct S<T*, int> {};
14340 Then, suppose we want to get `S<double*, int>'. The TPARMS will be
14341 {T}, the SPEC_ARGS will be {T*, int} and the ARGS will be {double*,
14342 int}. The resulting vector will be {double}, indicating that `T'
14343 is bound to `double'. */
14345 static tree
14347 {
14349 tree deduced_args;
14350 tree innermost_deduced_args;
14354 {
14358 innermost_deduced_args);
14359 }
14360 else
14366 UNIFY_ALLOW_NONE))
14373 /* Verify that nondeduced template arguments agree with the type
14374 obtained from argument deduction.
14376 For example:
14378 struct A { typedef int X; };
14379 template <class T, class U> struct C {};
14380 template <class T> struct C<T, typename T::X> {};
14382 Then with the instantiation `C<A, int>', we can deduce that
14383 `T' is `A' but unify () does not check whether `typename T::X'
14384 is `int'. */
14387 /* We only need to check the innermost arguments; the other
14388 arguments will always agree. */
14393 /* Now that we have bindings for all of the template arguments,
14394 ensure that the arguments deduced for the template template
14395 parameters have compatible template parameter lists. See the use
14396 of template_template_parm_bindings_ok_p in fn_type_unification
14397 for more information. */
14402 }
14404 /* TEMPLATES is a TREE_LIST. Each TREE_VALUE is a TEMPLATE_DECL.
14405 Return the TREE_LIST node with the most specialized template, if
14406 any. If there is no most specialized template, the error_mark_node
14407 is returned.
14409 Note that this function does not look at, or modify, the
14410 TREE_PURPOSE or TREE_TYPE of any of the nodes. Since the node
14411 returned is one of the elements of INSTANTIATIONS, callers may
14412 store information in the TREE_PURPOSE or TREE_TYPE of the nodes,
14413 and retrieve it from the value returned. */
14415 tree
14417 {
14424 {
14430 fate--;
14435 fate++;
14440 {
14441 /* Equally specialized, move to next function. If there
14442 is no next function, nothing's most specialized. */
14447 }
14448 }
14451 /* Now verify that champ is better than everything earlier in the
14452 instantiation list. */
14460 {
14463 }
14465 processing_template_decl--;
14471 }
14473 /* If DECL is a specialization of some template, return the most
14474 general such template. Otherwise, returns NULL_TREE.
14476 For example, given:
14478 template <class T> struct S { template <class U> void f(U); };
14480 if TMPL is `template <class U> void S<int>::f(U)' this will return
14481 the full template. This function will not trace past partial
14482 specializations, however. For example, given in addition:
14484 template <class T> struct S<T*> { template <class U> void f(U); };
14486 if TMPL is `template <class U> void S<int*>::f(U)' this will return
14487 `template <class T> template <class U> S<T*>::f(U)'. */
14489 tree
14491 {
14492 /* If DECL is a FUNCTION_DECL, find the TEMPLATE_DECL of which it is
14493 an immediate specialization. */
14495 {
14499 /* The DECL_TI_TEMPLATE can be an IDENTIFIER_NODE for a
14500 template friend. */
14505 }
14507 /* Look for more and more general templates. */
14509 {
14510 /* The DECL_TI_TEMPLATE can be an IDENTIFIER_NODE in some cases.
14511 (See cp-tree.h for details.) */
14519 /* Stop if we run into an explicitly specialized class template. */
14526 }
14529 }
14531 /* Return the most specialized of the class template partial
14532 specializations of TMPL which can produce TYPE, a specialization of
14533 TMPL. The value returned is actually a TREE_LIST; the TREE_TYPE is
14534 a _TYPE node corresponding to the partial specialization, while the
14535 TREE_PURPOSE is the set of template arguments that must be
14536 substituted into the TREE_TYPE in order to generate TYPE.
14538 If the choice of partial specialization is ambiguous, a diagnostic
14539 is issued, and the error_mark_node is returned. If there are no
14540 partial specializations of TMPL matching TYPE, then NULL_TREE is
14541 returned. */
14543 static tree
14545 {
14547 tree t;
14548 tree champ;
14551 tree args;
14557 /* For determining which partial specialization to use, only the
14558 innermost args are interesting. */
14560 {
14563 }
14566 {
14567 tree partial_spec_args;
14568 tree spec_args;
14573 {
14578 /* Discard the outer levels of args, and then substitute in the
14579 template args from the enclosing class. */
14581 partial_spec_args = tsubst_template_args
14584 /* PARMS already refers to just the innermost parms, but the
14585 template parms in partial_spec_args had their levels lowered
14586 by tsubst, so we need to do the same for the parm list. We
14587 can't just tsubst the TREE_VEC itself, as tsubst wants to
14588 treat a TREE_VEC as an argument vector. */
14595 }
14597 partial_spec_args,
14598 args);
14600 {
14605 }
14606 }
14616 {
14619 ;
14620 else
14621 {
14623 {
14626 {
14629 }
14630 }
14632 }
14633 }
14637 {
14640 {
14643 }
14644 }
14647 {
14651 {
14654 }
14656 }
14659 }
14661 /* Explicitly instantiate DECL. */
14663 void
14665 {
14670 /* An error occurred, for which grokdeclarator has already issued
14671 an appropriate message. */
14674 {
14677 }
14679 {
14680 /* There is an asymmetry here in the way VAR_DECLs and
14681 FUNCTION_DECLs are handled by grokdeclarator. In the case of
14682 the latter, the DECL we get back will be marked as a
14683 template instantiation, and the appropriate
14684 DECL_TEMPLATE_INFO will be set up. This does not happen for
14685 VAR_DECLs so we do the lookup here. Probably, grokdeclarator
14686 should handle VAR_DECLs as it currently handles
14687 FUNCTION_DECLs. */
14689 {
14692 }
14695 {
14698 }
14700 {
14705 }
14706 }
14708 {
14711 }
14712 else
14715 /* Check for various error cases. Note that if the explicit
14716 instantiation is valid the RESULT will currently be marked as an
14717 *implicit* instantiation; DECL_EXPLICIT_INSTANTIATION is not set
14718 until we get here. */
14721 {
14722 /* DR 259 [temp.spec].
14724 Both an explicit instantiation and a declaration of an explicit
14725 specialization shall not appear in a program unless the explicit
14726 instantiation follows a declaration of the explicit specialization.
14728 For a given set of template parameters, if an explicit
14729 instantiation of a template appears after a declaration of an
14730 explicit specialization for that template, the explicit
14731 instantiation has no effect. */
14733 }
14735 {
14736 /* [temp.spec]
14738 No program shall explicitly instantiate any template more
14739 than once.
14741 We check DECL_NOT_REALLY_EXTERN so as not to complain when
14742 the first instantiation was `extern' and the second is not,
14743 and EXTERN_P for the opposite case. */
14746 /* If an "extern" explicit instantiation follows an ordinary
14747 explicit instantiation, the template is instantiated. */
14750 }
14752 {
14755 }
14757 {
14760 }
14763 ;
14765 {
14768 "ISO C++ 1998 forbids the use of %<extern%> on explicit "
14771 }
14772 else
14780 }
14782 static void
14784 {
14790 {
14793 }
14794 }
14796 /* Called from do_type_instantiation through binding_table_foreach to
14797 do recursive instantiation for the type bound in ENTRY. */
14798 static void
14800 {
14806 }
14808 /* Called from do_type_instantiation to instantiate a member
14809 (a member function or a static member variable) of an
14810 explicitly instantiated class template. */
14811 static void
14813 {
14818 }
14820 /* Perform an explicit instantiation of template class T. STORAGE, if
14821 non-null, is the RID for extern, inline or static. COMPLAIN is
14822 nonzero if this is called from the parser, zero if called recursively,
14823 since the standard is unclear (as detailed below). */
14825 void
14827 {
14837 {
14840 }
14845 {
14848 t);
14850 }
14853 {
14855 {
14857 {
14860 "ISO C++ 1998 forbids the use of %<extern%> on "
14862 }
14863 else
14865 "ISO C++ forbids the use of %qE"
14867 }
14875 else
14876 {
14878 storage);
14880 }
14881 }
14884 {
14885 /* DR 259 [temp.spec].
14887 Both an explicit instantiation and a declaration of an explicit
14888 specialization shall not appear in a program unless the explicit
14889 instantiation follows a declaration of the explicit specialization.
14891 For a given set of template parameters, if an explicit
14892 instantiation of a template appears after a declaration of an
14893 explicit specialization for that template, the explicit
14894 instantiation has no effect. */
14896 }
14898 {
14899 /* [temp.spec]
14901 No program shall explicitly instantiate any template more
14902 than once.
14904 If PREVIOUS_INSTANTIATION_EXTERN_P, then the first explicit
14905 instantiation was `extern'. If EXTERN_P then the second is.
14906 These cases are OK. */
14913 /* If we've already instantiated the template, just return now. */
14916 }
14924 {
14925 tree tmp;
14927 /* In contrast to implicit instantiation, where only the
14928 declarations, and not the definitions, of members are
14929 instantiated, we have here:
14931 [temp.explicit]
14933 The explicit instantiation of a class template specialization
14934 implies the instantiation of all of its members not
14935 previously explicitly specialized in the translation unit
14936 containing the explicit instantiation.
14938 Of course, we can't instantiate member template classes, since
14939 we don't have any arguments for them. Note that the standard
14940 is unclear on whether the instantiation of the members are
14941 *explicit* instantiations or not. However, the most natural
14942 interpretation is that it should be an explicit instantiation. */
14957 }
14958 }
14960 /* Given a function DECL, which is a specialization of TMPL, modify
14961 DECL to be a re-instantiation of TMPL with the same template
14962 arguments. TMPL should be the template into which tsubst'ing
14963 should occur for DECL, not the most general template.
14965 One reason for doing this is a scenario like this:
14967 template <class T>
14968 void f(const T&, int i);
14970 void g() { f(3, 7); }
14972 template <class T>
14973 void f(const T& t, const int i) { }
14975 Note that when the template is first instantiated, with
14976 instantiate_template, the resulting DECL will have no name for the
14977 first parameter, and the wrong type for the second. So, when we go
14978 to instantiate the DECL, we regenerate it. */
14980 static void
14982 {
14983 /* The arguments used to instantiate DECL, from the most general
14984 template. */
14985 tree args;
14986 tree code_pattern;
14991 /* Make sure that we can see identifiers, and compute access
14992 correctly. */
14996 {
14997 tree decl_parm;
14998 tree pattern_parm;
14999 tree specs;
15012 specs);
15014 /* Merge parameter declarations. */
15017 pattern_parm
15021 {
15022 tree parm_type;
15023 tree attributes;
15028 NULL_TREE);
15034 {
15037 }
15040 }
15041 /* Merge any parameters that match with the function parameter
15042 pack. */
15044 {
15046 tree expanded_types;
15047 /* Expand the TYPE_PACK_EXPANSION that provides the types for
15048 the parameters in this function parameter pack. */
15053 {
15054 tree parm_type;
15055 tree attributes;
15058 /* Rename the parameter to include the index. */
15067 {
15070 }
15072 }
15073 }
15074 /* Merge additional specifiers from the CODE_PATTERN. */
15078 }
15084 else
15088 }
15090 /* Return the TEMPLATE_DECL into which DECL_TI_ARGS(DECL) should be
15091 substituted to get DECL. */
15093 tree
15095 {
15098 /* Set TMPL to the template whose DECL_TEMPLATE_RESULT is the pattern
15099 for the instantiation. This is not always the most general
15100 template. Consider, for example:
15102 template <class T>
15103 struct S { template <class U> void f();
15104 template <> void f<int>(); };
15106 and an instantiation of S<double>::f<int>. We want TD to be the
15107 specialization S<T>::f<int>, not the more general S<T>::f<U>. */
15109 more general template. */
15111 /* We must also deal with friend templates. Given:
15113 template <class T> struct S {
15114 template <class U> friend void f() {};
15115 };
15117 S<int>::f<U> say, is not an instantiation of S<T>::f<U>,
15118 so far as the language is concerned, but that's still
15119 where we get the pattern for the instantiation from. On
15120 other hand, if the definition comes outside the class, say:
15122 template <class T> struct S {
15123 template <class U> friend void f();
15124 };
15125 template <class U> friend void f() {}
15127 we don't need to look any further. That's what the check for
15128 DECL_INITIAL is for. */
15132 {
15133 /* The present template, TD, should not be a definition. If it
15134 were a definition, we should be using it! Note that we
15135 cannot restructure the loop to just keep going until we find
15136 a template with a definition, since that might go too far if
15137 a specialization was declared, but not defined. */
15141 /* Fetch the more general template. */
15143 }
15146 }
15148 /* Produce the definition of D, a _DECL generated from a template. If
15149 DEFER_OK is nonzero, then we don't have to actually do the
15150 instantiation now; we just have to do it sometime. Normally it is
15151 an error if this is an explicit instantiation but D is undefined.
15152 EXPL_INST_CLASS_MEM_P is true iff D is a member of an
15153 explicitly instantiated class template. */
15155 tree
15158 {
15160 tree gen_args;
15161 tree args;
15162 tree td;
15163 tree code_pattern;
15164 tree spec;
15165 tree gen_tmpl;
15171 /* This function should only be used to instantiate templates for
15172 functions and static member variables. */
15176 /* Variables are never deferred; if instantiation is required, they
15177 are instantiated right away. That allows for better code in the
15178 case that an expression refers to the value of the variable --
15179 if the variable has a constant value the referring expression can
15180 take advantage of that fact. */
15184 /* Don't instantiate cloned functions. Instead, instantiate the
15185 functions they cloned. */
15190 /* D has already been instantiated. It might seem reasonable to
15191 check whether or not D is an explicit instantiation, and, if so,
15192 stop here. But when an explicit instantiation is deferred
15193 until the end of the compilation, DECL_EXPLICIT_INSTANTIATION
15194 is set, even though we still need to do the instantiation. */
15197 /* If we already have a specialization of this declaration, then
15198 there's no reason to instantiate it. Note that
15199 retrieve_specialization gives us both instantiations and
15200 specializations, so we must explicitly check
15201 DECL_TEMPLATE_SPECIALIZATION. */
15209 /* This needs to happen before any tsubsting. */
15215 /* Set TD to the template whose DECL_TEMPLATE_RESULT is the pattern
15216 for the instantiation. */
15220 /* We should never be trying to instantiate a member of a class
15221 template or partial specialization. */
15226 /* In the case of a friend template whose definition is provided
15227 outside the class, we may have too many arguments. Drop the
15228 ones we don't need. The same is true for specializations. */
15229 args = get_innermost_template_args
15231 else
15236 else
15239 /* We may be in the middle of deferred access check. Disable it now. */
15242 /* Unless an explicit instantiation directive has already determined
15243 the linkage of D, remember that a definition is available for
15244 this entity. */
15252 /* If D is a member of an explicitly instantiated class template,
15253 and no definition is available, treat it like an implicit
15254 instantiation. */
15257 {
15261 }
15264 {
15265 /* Recheck the substitutions to obtain any warning messages
15266 about ignoring cv qualifiers. */
15270 /* Make sure that we can see identifiers, and compute access
15271 correctly. D is already the target FUNCTION_DECL with the
15272 right context. */
15276 {
15279 d);
15280 /* Don't simply tsubst the function type, as that will give
15281 duplicate warnings about poor parameter qualifications.
15282 The function arguments are the same as the decl_arguments
15283 without the top level cv qualifiers. */
15285 }
15289 }
15291 /* Check to see whether we know that this template will be
15292 instantiated in some other file, as with "extern template"
15293 extension. */
15295 /* In general, we do not instantiate such templates... */
15297 /* ... but we instantiate inline functions so that we can inline
15298 them. An explicit instantiation declaration prohibits implicit
15299 instantiation of non-inline functions. With high levels of
15300 optimization, we would normally inline non-inline functions
15301 -- but we're not allowed to do that for "extern template" functions.
15302 Therefore, we check DECL_DECLARED_INLINE_P, rather than
15303 possibly_inlined_p. And ... */
15306 /* ... we instantiate static data members whose values are
15307 needed in integral constant expressions. */
15311 /* Defer all other templates, unless we have been explicitly
15312 forbidden from doing so. */
15314 template. */
15315 ! pattern_defined
15316 /* If it's OK to postpone instantiation, do so. */
15317 || defer_ok
15318 /* If this is a static data member that will be defined
15319 elsewhere, we don't want to instantiate the entire data
15320 member, but we do want to instantiate the initializer so that
15321 we can substitute that elsewhere. */
15323 {
15324 /* The definition of the static data member is now required so
15325 we must substitute the initializer. */
15329 {
15330 tree ns;
15331 tree init;
15337 args,
15342 LOOKUP_ONLYCONVERTING);
15345 }
15347 /* We restore the source position here because it's used by
15348 add_pending_template. */
15354 /* [temp.explicit]
15356 The definition of a non-exported function template, a
15357 non-exported member function template, or a non-exported
15358 member function or static data member of a class template
15359 shall be present in every translation unit in which it is
15360 explicitly instantiated. */
15364 /* ??? Historically, we have instantiated inline functions, even
15365 when marked as "extern template". */
15369 }
15370 /* Tell the repository that D is available in this translation unit
15371 -- and see if it is supposed to be instantiated here. */
15373 {
15374 /* In a PCH file, despite the fact that the repository hasn't
15375 requested instantiation in the PCH it is still possible that
15376 an instantiation will be required in a file that includes the
15377 PCH. */
15380 /* Instantiate inline functions so that the inliner can do its
15381 job, even though we'll not be emitting a copy of this
15382 function. */
15385 }
15391 /* Mark D as instantiated so that recursive calls to
15392 instantiate_decl do not try to instantiate it again. */
15395 /* Regenerate the declaration in case the template has been modified
15396 by a subsequent redeclaration. */
15399 /* We already set the file and line above. Reset them now in case
15400 they changed as a result of calling regenerate_decl_from_template. */
15404 {
15405 tree init;
15407 /* Clear out DECL_RTL; whatever was there before may not be right
15408 since we've reset the type of the declaration. */
15412 /* The initializer is placed in DECL_INITIAL by
15413 regenerate_decl_from_template. Pull it out so that
15414 finish_decl can process it. */
15419 /* Clear DECL_EXTERNAL so that cp_finish_decl will process the
15420 initializer. That function will defer actual emission until
15421 we have a chance to determine linkage. */
15424 /* Enter the scope of D so that access-checking works correctly. */
15428 }
15430 {
15431 htab_t saved_local_specializations;
15432 tree subst_decl;
15433 tree tmpl_parm;
15434 tree spec_parm;
15436 /* Save away the current list, in case we are instantiating one
15437 template from within the body of another. */
15440 /* Set up the list of local specializations. */
15442 hash_local_specialization,
15443 eq_local_specializations,
15444 NULL);
15446 /* Set up context. */
15449 /* Create substitution entries for the parameters. */
15454 {
15458 }
15460 {
15464 }
15466 {
15467 /* Collect all of the extra "packed" parameters into an
15468 argument pack. */
15469 tree parmvec;
15470 tree parmtypevec;
15474 tree t;
15476 /* Count how many parameters remain. */
15478 len++;
15480 /* Fill in PARMVEC and PARMTYPEVEC with all of the parameters. */
15484 {
15487 }
15489 /* Build the argument packs. */
15494 /* Register the (value) argument pack as a specialization of
15495 TMPL_PARM, then move on. */
15498 }
15501 /* Substitute into the body of the function. */
15506 /* Set the current input_location to the end of the function
15507 so that finish_function knows where we are. */
15510 /* We don't need the local specializations any more. */
15514 /* Finish the function. */
15517 }
15519 /* We're not deferring instantiation any more. */
15525 out:
15533 }
15535 /* Run through the list of templates that we wish we could
15536 instantiate, and instantiate any we can. RETRIES is the
15537 number of times we retry pending template instantiation. */
15539 void
15541 {
15545 /* Instantiating templates may trigger vtable generation. This in turn
15546 may require further template instantiations. We place a limit here
15547 to avoid infinite loop. */
15549 {
15553 " instantiating %q+D, possibly from virtual table generation"
15557 /* Pretend that we defined it. */
15560 }
15562 do
15563 {
15568 {
15573 {
15574 tree fn;
15577 {
15581 fn;
15589 }
15592 }
15593 else
15594 {
15597 {
15598 instantiation
15604 }
15608 }
15611 /* If INSTANTIATION has been instantiated, then we don't
15612 need to consider it again in the future. */
15614 else
15615 {
15618 }
15621 }
15623 }
15627 }
15629 /* Substitute ARGVEC into T, which is a list of initializers for
15630 either base class or a non-static data member. The TREE_PURPOSEs
15631 are DECLs, and the TREE_VALUEs are the initializer values. Used by
15632 instantiate_decl. */
15634 static tree
15636 {
15640 {
15641 tree decl;
15642 tree init;
15648 {
15649 tree expr;
15650 tree arg;
15652 /* Expand the base class expansion type into separate base
15653 classes. */
15655 tf_warning_or_error,
15656 NULL_TREE);
15660 /* We'll be building separate TREE_LISTs of arguments for
15661 each base. */
15667 /* Build a dummy EXPR_PACK_EXPANSION that will be used to
15668 expand each argument in the TREE_VALUE of t. */
15674 /* VOID_TYPE_NODE is used to indicate
15675 value-initialization. */
15676 {
15679 }
15680 else
15681 {
15682 /* Substitute parameter packs into each argument in the
15683 TREE_LIST. */
15686 {
15687 tree expanded_exprs;
15689 /* Expand the argument. */
15691 expanded_exprs
15693 tf_warning_or_error,
15694 NULL_TREE);
15698 /* Prepend each of the expanded expressions to the
15699 corresponding TREE_LIST in EXPANDED_ARGUMENTS. */
15701 {
15706 }
15707 }
15710 /* Reverse all of the TREE_LISTs in EXPANDED_ARGUMENTS,
15711 since we built them backwards. */
15713 {
15716 }
15717 }
15718 }
15721 {
15723 {
15727 }
15728 else
15729 {
15741 }
15744 {
15748 }
15749 }
15750 }
15752 }
15754 /* Set CURRENT_ACCESS_SPECIFIER based on the protection of DECL. */
15756 static void
15758 {
15763 else
15765 }
15767 /* Instantiate an enumerated type. TAG is the template type, NEWTAG
15768 is the instantiation (which should have been created with
15769 start_enum) and ARGS are the template arguments to use. */
15771 static void
15773 {
15774 tree e;
15777 {
15778 tree value;
15779 tree decl;
15782 /* Note that in a template enum, the TREE_VALUE is the
15783 CONST_DECL, not the corresponding INTEGER_CST. */
15788 /* Give this enumeration constant the correct access. */
15791 /* Actually build the enumerator itself. */
15793 }
15798 }
15800 /* DECL is a FUNCTION_DECL that is a template specialization. Return
15801 its type -- but without substituting the innermost set of template
15802 arguments. So, innermost set of template parameters will appear in
15803 the type. */
15805 tree
15807 {
15808 tree fn_type;
15809 tree tmpl;
15810 tree targs;
15811 tree tparms;
15819 /* There should be as many levels of arguments as there are levels
15820 of parameters. */
15826 /* No substitution is necessary. */
15827 ;
15828 else
15829 {
15831 tree partial_args;
15833 /* Replace the innermost level of the TARGS with NULL_TREEs to
15834 let tsubst know not to substitute for those parameters. */
15843 /* Disable access control as this function is used only during
15844 name-mangling. */
15849 /* Now, do the (partial) substitution to figure out the
15850 appropriate function type. */
15854 /* Substitute into the template parameters to obtain the real
15855 innermost set of parameters. This step is important if the
15856 innermost set of template parameters contains value
15857 parameters whose types depend on outer template parameters. */
15862 }
15865 }
15867 /* Return truthvalue if we're processing a template different from
15868 the last one involved in diagnostics. */
15869 int
15871 {
15873 }
15875 /* Remember current template involved in diagnostics. */
15876 void
15878 {
15880 }
15884 {
15886 }
15888 /* [temp.param] Check that template non-type parm TYPE is of an allowable
15889 type. Return zero for ok, nonzero for disallowed. Issue error and
15890 warning messages under control of COMPLAIN. */
15892 static int
15894 {
15909 }
15911 /* Returns TRUE if TYPE is dependent, in the sense of [temp.dep.type].
15912 Assumes that TYPE really is a type, and not the ERROR_MARK_NODE.*/
15914 static bool
15916 {
15917 tree scope;
15919 /* [temp.dep.type]
15921 A type is dependent if it is:
15923 -- a template parameter. Template template parameters are types
15924 for us (since TYPE_P holds true for them) so we handle
15925 them here. */
15929 /* -- a qualified-id with a nested-name-specifier which contains a
15930 class-name that names a dependent type or whose unqualified-id
15931 names a dependent type. */
15934 /* -- a cv-qualified type where the cv-unqualified type is
15935 dependent. */
15937 /* -- a compound type constructed from any dependent type. */
15947 {
15948 tree arg_type;
15953 arg_type;
15958 }
15959 /* -- an array type constructed from any dependent type or whose
15960 size is specified by a constant expression that is
15961 value-dependent. */
15963 {
15968 }
15971 {
15972 /* If this is the TYPE_DOMAIN of an array type, consider it
15973 dependent. */
15976 }
15978 /* -- a template-id in which either the template name is a template
15979 parameter ... */
15982 /* ... or any of the template arguments is a dependent type or
15983 an expression that is type-dependent or value-dependent. */
15985 && (any_dependent_template_arguments_p
15989 /* All TYPEOF_TYPEs and DECLTYPE_TYPEs are dependent; if the
15990 argument of the `typeof' expression is not type-dependent, then
15991 it should already been have resolved. */
15996 /* A template argument pack is dependent if any of its packed
15997 arguments are. */
15999 {
16005 }
16007 /* All TYPE_PACK_EXPANSIONs are dependent, because parameter packs must
16008 be template parameters. */
16012 /* The standard does not specifically mention types that are local
16013 to template functions or local classes, but they should be
16014 considered dependent too. For example:
16016 template <int I> void f() {
16017 enum E { a = I };
16018 S<sizeof (E)> s;
16019 }
16021 The size of `E' cannot be known until the value of `I' has been
16022 determined. Therefore, `E' must be considered dependent. */
16029 /* Other types are non-dependent. */
16031 }
16033 /* Returns TRUE if TYPE is dependent, in the sense of
16034 [temp.dep.type]. */
16036 bool
16038 {
16039 /* If there are no template parameters in scope, then there can't be
16040 any dependent types. */
16042 {
16043 /* If we are not processing a template, then nobody should be
16044 providing us with a dependent type. */
16048 }
16050 /* If the type is NULL, we have not computed a type for the entity
16051 in question; in that case, the type is dependent. */
16055 /* Erroneous types can be considered non-dependent. */
16059 /* If we have not already computed the appropriate value for TYPE,
16060 do so now. */
16062 {
16065 }
16068 }
16070 /* Returns TRUE if EXPRESSION is dependent, according to CRITERION. */
16072 static bool
16074 {
16075 tree scope;
16076 tree name;
16086 /* [temp.dep.expr]
16088 An id-expression is type-dependent if it contains a
16089 nested-name-specifier that contains a class-name that names a
16090 dependent type. */
16091 /* The suggested resolution to Core Issue 2 implies that if the
16092 qualifying type is the current class, then we must peek
16093 inside it. */
16102 }
16104 /* Returns TRUE if the EXPRESSION is value-dependent, in the sense of
16105 [temp.dep.constexpr]. EXPRESSION is already known to be a constant
16106 expression. */
16108 bool
16110 {
16114 /* A name declared with a dependent type. */
16119 {
16121 /* A name that has not been looked up -- must be dependent. */
16125 /* A non-type template parm. */
16129 /* A non-type template parm. */
16135 /* A constant with integral or enumeration type and is initialized
16136 with an expression that is value-dependent. */
16148 /* These expressions are value-dependent if the type to which
16149 the cast occurs is dependent or the expression being casted
16150 is value-dependent. */
16151 {
16157 /* A functional cast has a list of operands. */
16160 {
16161 /* If there are no operands, it must be an expression such
16162 as "int()". This should not happen for aggregate types
16163 because it would form non-constant expressions. */
16167 }
16173 }
16177 /* A `sizeof' expression is value-dependent if the operand is
16178 type-dependent or is a pack expansion. */
16194 /* A CALL_EXPR may appear in a constant expression if it is a
16195 call to a builtin function, e.g., __builtin_constant_p. All
16196 such calls are value-dependent. */
16200 /* A NONTYPE_ARGUMENT_PACK is value-dependent if any packed argument
16201 is value-dependent. */
16202 {
16211 }
16214 {
16218 }
16225 /* A constant expression is value-dependent if any subexpression is
16226 value-dependent. */
16228 {
16238 || (value_dependent_expression_p
16243 {
16246 /* In some cases, some of the operands may be missing.
16247 (For example, in the case of PREDECREMENT_EXPR, the
16248 amount to increment by may be missing.) That doesn't
16249 make the expression dependent. */
16251 && (value_dependent_expression_p
16255 }
16259 }
16260 }
16262 /* The expression is not value-dependent. */
16264 }
16266 /* Returns TRUE if the EXPRESSION is type-dependent, in the sense of
16267 [temp.dep.expr]. */
16269 bool
16271 {
16278 /* An unresolved name is always dependent. */
16283 /* Some expression forms are never type-dependent. */
16294 /* The types of these expressions depends only on the type to which
16295 the cast occurs. */
16303 /* The types of these expressions depends only on the type created
16304 by the expression. */
16307 {
16308 /* For NEW_EXPR tree nodes created inside a template, either
16309 the object type itself or a TREE_LIST may appear as the
16310 operand 1. */
16313 /* This is an array type. We need to check array dimensions
16314 as well. */
16316 || value_dependent_expression_p
16318 else
16320 }
16324 type_dependent_expression_p))
16330 && (any_dependent_template_arguments_p
16342 {
16343 tree elt;
16347 {
16350 }
16352 }
16355 {
16360 {
16366 }
16367 /* SCOPE_REF with non-null TREE_TYPE is always non-dependent. */
16375 {
16380 }
16385 {
16389 }
16391 }
16396 }
16398 /* Returns TRUE if ARGS (a TREE_LIST of arguments to a function call)
16399 contains a type-dependent expression. */
16401 bool
16403 {
16405 {
16411 }
16413 }
16415 /* Returns TRUE if LIST (a TREE_LIST whose TREE_VALUEs are
16416 expressions) contains any value-dependent expressions. */
16418 bool
16420 {
16426 }
16428 /* Returns TRUE if the ARG (a template argument) is dependent. */
16430 bool
16432 {
16440 {
16444 {
16447 }
16450 }
16453 else
16456 }
16458 /* Returns true if ARGS (a collection of template arguments) contains
16459 any types that require structural equality testing. */
16461 bool
16463 {
16473 {
16476 {
16482 {
16483 /* Look inside the argument pack. */
16486 }
16489 {
16503 }
16504 }
16505 }
16508 }
16510 /* Returns true if ARGS (a collection of template arguments) contains
16511 any dependent arguments. */
16513 bool
16515 {
16525 {
16530 }
16533 }
16535 /* Returns TRUE if the template TMPL is dependent. */
16537 bool
16539 {
16541 {
16543 {
16547 }
16549 }
16551 /* Template template parameters are dependent. */
16555 /* So are names that have not been looked up. */
16559 /* So are member templates of dependent classes. */
16563 }
16565 /* Returns TRUE if the specialization TMPL<ARGS> is dependent. */
16567 bool
16569 {
16572 }
16574 /* Returns TRUE if OMP_FOR with DECLV, INITV, CONDV and INCRV vectors
16575 is dependent. */
16577 bool
16579 {
16586 {
16607 {
16611 }
16615 {
16619 {
16624 }
16625 }
16626 }
16629 }
16631 /* TYPE is a TYPENAME_TYPE. Returns the ordinary TYPE to which the
16632 TYPENAME_TYPE corresponds. Returns the original TYPENAME_TYPE if
16633 no such TYPE can be found. Note that this function peers inside
16634 uninstantiated templates and therefore should be used only in
16635 extremely limited situations. ONLY_CURRENT_P restricts this
16636 peering to the currently open classes hierarchy (which is required
16637 when comparing types). */
16639 tree
16641 {
16642 tree scope;
16643 tree name;
16644 tree decl;
16646 tree pushed_scope;
16647 tree result;
16654 /* If the SCOPE is itself a TYPENAME_TYPE, then we need to resolve
16655 it first before we can figure out what NAME refers to. */
16658 /* If we don't know what SCOPE refers to, then we cannot resolve the
16659 TYPENAME_TYPE. */
16662 /* If the SCOPE is a template type parameter, we have no way of
16663 resolving the name. */
16666 /* If the SCOPE is not the current instantiation, there's no reason
16667 to look inside it. */
16670 /* If SCOPE isn't the template itself, it will not have a valid
16671 TYPE_FIELDS list. */
16673 /* scope is either the template itself or a compatible instantiation
16674 like X<T>, so look up the name in the original template. */
16676 else
16677 /* scope is a partial instantiation, so we can't do the lookup or we
16678 will lose the template arguments. */
16680 /* Enter the SCOPE so that name lookup will be resolved as if we
16681 were in the class definition. In particular, SCOPE will no
16682 longer be considered a dependent type. */
16684 /* Look up the declaration. */
16689 /* For a TYPENAME_TYPE like "typename X::template Y<T>", we want to
16690 find a TEMPLATE_DECL. Otherwise, we want to find a TYPE_DECL. */
16695 {
16699 }
16702 {
16703 tree tmpl;
16704 tree args;
16705 /* Obtain the template and the arguments. */
16708 /* Instantiate the template. */
16714 }
16716 /* Leave the SCOPE. */
16720 /* If we failed to resolve it, return the original typename. */
16724 /* If lookup found a typename type, resolve that too. */
16726 {
16727 /* Ill-formed programs can cause infinite recursion here, so we
16728 must catch that. */
16732 }
16734 /* Qualify the resulting type. */
16740 }
16742 /* EXPR is an expression which is not type-dependent. Return a proxy
16743 for EXPR that can be used to compute the types of larger
16744 expressions containing EXPR. */
16746 tree
16748 {
16749 tree inner_expr;
16751 /* Preserve null pointer constants so that the type of things like
16752 "p == 0" where "p" is a pointer can be determined. */
16755 /* Preserve OVERLOADs; the functions must be available to resolve
16756 types. */
16767 /* There is no need to return a proxy for a variable. */
16770 /* Preserve string constants; conversions from string constants to
16771 "char *" are allowed, even though normally a "const char *"
16772 cannot be used to initialize a "char *". */
16775 /* Preserve arithmetic constants, as an optimization -- there is no
16776 reason to create a new node. */
16779 /* Preserve THROW_EXPRs -- all throw-expressions have type "void".
16780 There is at least one place where we want to know that a
16781 particular expression is a throw-expression: when checking a ?:
16782 expression, there are special rules if the second or third
16783 argument is a throw-expression. */
16802 /* If the type is unknown, it can't really be non-dependent */
16805 /* Otherwise, build a NON_DEPENDENT_EXPR.
16807 REFERENCE_TYPEs are not stripped for expressions in templates
16808 because doing so would play havoc with mangling. Consider, for
16809 example:
16811 template <typename T> void f<T& g>() { g(); }
16813 In the body of "f", the expression for "g" will have
16814 REFERENCE_TYPE, even though the standard says that it should
16815 not. The reason is that we must preserve the syntactic form of
16816 the expression so that mangling (say) "f<g>" inside the body of
16817 "f" works out correctly. Therefore, the REFERENCE_TYPE is
16818 stripped here. */
16820 }
16822 /* ARGS is a TREE_LIST of expressions as arguments to a function call.
16823 Return a new TREE_LIST with the various arguments replaced with
16824 equivalent non-dependent expressions. */
16826 tree
16828 {
16829 tree a;
16830 tree new_args;
16836 new_args);
16838 }
16840 /* Returns a type which represents 'auto'. We use a TEMPLATE_TYPE_PARM
16841 with a level one deeper than the actual template parms. */
16843 tree
16845 {
16846 tree au;
16848 /* ??? Is it worth caching this for multiple autos at the same level? */
16860 }
16862 /* Replace auto in TYPE with std::initializer_list<auto>. */
16864 static tree
16866 {
16867 tree std_init_list = namespace_binding
16869 tree argvec;
16870 tree init_auto;
16872 {
16876 }
16886 }
16888 /* Replace occurrences of 'auto' in TYPE with the appropriate type deduced
16889 from INIT. AUTO_NODE is the TEMPLATE_TYPE_PARM used for 'auto' in TYPE. */
16891 tree
16893 {
16897 /* [dcl.spec.auto]: Obtain P from T by replacing the occurrences of auto
16898 with either a new invented type template parameter U or, if the
16899 initializer is a braced-init-list (8.5.4), with
16900 std::initializer_list<U>. */
16913 {
16916 }
16921 }
16923 /* Substitutes LATE_RETURN_TYPE for 'auto' in TYPE and returns the
16924 result. */
16926 tree
16928 {
16929 tree argvec;
16938 }
16940 /* Returns true iff TYPE is a TEMPLATE_TYPE_PARM representing 'auto'. */
16942 bool
16944 {
16948 else
16950 }
16952 /* Returns true iff TYPE contains a use of 'auto'. Since auto can only
16953 appear as a type-specifier for the declaration in question, we don't
16954 have to look through the whole type. */
16956 tree
16958 {
16975 }